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CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is based on Japanese Patent Application No. 2001-168047 filed in Japan on Jun. 4, 2001, the entire content of which is hereby incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an extracting method, an extracting apparatus, a separating method and a separating apparatus. The invention relates to a technique for selectively extracting an object contained in a liquid. [0004] 2. Description of the Related Art [0005] In recent years, dioxin or the like generated from garbage incinerators and the like is recognized as serious environmental problem, and it is an important problem to measure and manage a discharge density of the dioxin. Currently, a method of measuring a density of the dioxin or the like is defined by Japanese Industrial Standards (JIS). [0006] In the case where the dioxin or the like is measured, in order to extract the dioxin contained in water, similarly to a conventional solvent extracting method, water and an organic solvent are put into a separating funnel or the like and are shaken to be mixed, the dioxin in the water is incorporated into the organic solvent and only the organic solvent is extracted so as to be separated from the water. [0007] However, this method requires a lot of solvent, long time and a lot of costs. [0008] Recently, an attention is paid to μ-TAS (μ-Total Analysis System) which refines chemical analysis and synthesizing apparatuses and chemical analysis and synthesizing methods using a micromachine technique. The μ-TAS, which is refined more finely as compared with conventional apparatuses, has the merits such that an amount of samples is small, reacting time is short and an amount of refuse is small. In the case where the μ-TAS is adapted to the environment measuring field or the like, it has the merits that usage of reagent and organic solvent is small and reacting time (measuring time) is short, and further since an apparatus is small, the measurement can be made on the ground, so that the immediacy of an inspection is expected to be improved. [0009] However, conventionally a technique for extracting a solvent using a micro fluid system to which the micromachine technique is applied has not been found. [0010] For example, in a very narrow channel having a width of several dozen to several hundred μm, the viscosity of a liquid is dominant, and it is difficult to stir and mix liquids. For this reason, in order to incorporate the dioxin contained in the water into the organic solvent, it is inefficient to stir water and organic solvent in a channel. [0011] In addition, it is desirable that only an organic solvent is extracted from a small amount of mixed water and organic solvent in a microarea and to separate it from the water. SUMMARY OF THE INVENTION [0012] Therefore, a first technical problem to be solved by the invention is to provide an extracting method, an extracting apparatus and a chip for the extracting apparatus which incorporate a substance contained in a first liquid into a second liquid efficiently in a microarea. [0013] In addition, a second technical problem to be solved by the present invention suggests a separating method, a separating apparatus and a chip for the separating apparatus which separate a second liquid from mixed first liquid and second liquid in a microarea. [0014] In order to solve the first technical problem, the present invention provides an extracting method which is basically characterized in that a layered first liquid and a layered second liquid come in contact with each other, and a substance in a first laminar flow of the first liquid is moved into a second laminar flow of the second liquid. More concretely, the following extracting method is provided. [0015] The extracting method is to incorporate the substance contained in the first liquid into the second liquid so as to extract the substance. This extracting method has the first step and the second step. In the first step, the first liquid and the second liquid are transferred into a channel so as to alternately come in contact with each other respectively in not less than one or two laminar state, and the substance in the first laminar flow of the first liquid is moved to the second laminar flow of the second liquid. In the second step, the second liquid is separated from the first liquid in a lower stream side of the channel. [0016] In the first step, the first fluid and the second fluid are allowed to flow into the channel with a very small width so as to be in the laminar state. When two or more first laminar flows and the second laminar flows exist, the first laminar flows and the second laminar flows are arranged alternately so as to come in contact with each other. [0017] Generally the substance in the liquid diffuses voluntarily. Namely, molecules of a medium (liquid) continually collide with small matters (particles of the substance) in the medium, and the small matters move irregularly in the medium. Due to this Brownian movement, the small matters diffuse in the medium. A relative interfacial area of the liquid becomes large in the microarea (namely, a surface area becomes wider as compared with a volume), and the diffusion speed becomes abruptly high. For this reason, the particles of the substance in the first laminar flow move to the second laminar flow quickly. Namely, the particles are incorporated into the second liquid. In this case, it is preferable that the particles of the substance difficultly return from the second laminar flow to the first laminar flow, and for example, it is preferable that the substance is easily incorporated into the second liquid easier than into the first liquid. When the substance is dioxin or the like, the first fluid can be water and the second fluid can be an organic solvent. Moreover, in order to diffuse it efficiently, it is preferable that a flow velocity of the first laminar flow is equal with a flow velocity of the second laminar flow and the flow velocities do not relatively differ. [0018] According to the above method, the flow of the laminar flow and the particle diffusion phenomenon in the channel are used, so that the substance contained in the first liquid can be incorporated into the second liquid efficiently in the microarea. [0019] In the first step, even if the liquids are sequentially transferred, the liquids may be stopped in the middle of the channel. [0020] In the second step, only the second liquid is collected, so that the substance contained in the first liquid can be extracted. [0021] Preferably at the first step, a width of one laminar flow is not more than 50 μm. When the width is not more than 50 μm, a Reynolds number becomes small, and the liquid is easily transferred in the channel in the laminar state. [0022] The second step can collect only the second liquid in the following various forms. [0023] Preferably, the second step includes a channel branching step. In the channel branching step, in the lower stream side of the channel, the first laminar flow is allowed to flow into a first branch channel, and the second laminar flow is allowed to flow in a second branch channel. In this case, the channels is branched for each liquid in the laminar state, so that the second liquid can be separated from the first liquid easily. [0024] Preferably, the second step includes a charging step. In the charging step, a vicinity of an inlet of the first branch channel or the second branch channel is charged. Polarity is provided to the first liquid or the second liquid and the other liquid has no polarity by the charging step, one liquid having a polarity is activated so as to enter the charged first branch channel or second branch channel, and thus the liquids can be separated more efficiently. For example, nonpolar molecules such as petroleum ether, carbon tetrachloride, benzene, xylene, nitrobenzene and iodine can be separated from water having polarity. As for a mixed liquid composed of three or more liquids, in the case where only one liquid has polarity or where only one liquid is nonpolar, the one liquid can be separated from the other liquids. [0025] In addition, the present invention provides the following separating method in order to solve the second technical problem. [0026] The separating method separates a second liquid from mixed first liquid and second liquid. The separating method has the first step and the second step. In the first step, the mixed first liquid and second liquid are allowed to flow into the channel. The channel is composed of a first space and a second space. The first space is provided with a microstructure, and one of the first liquid and the second liquid easily flows relatively. The second space extends along the first space and is connected with the first space. In the second step, the second liquid is collected in a lower stream side of the first space or the second space in which the second liquid flows. [0027] According to the above method, when the mixed first and second liquids are allowed to flow in the channel, one of the first and second liquids which easily flow relatively into the first space flows in the first space, and the other liquid flows in the second space. For example, the structures undergo a hydrophilic treatment and are provided with a suitable functional group, so that one of the first and second liquids can easily flow relatively in the first space. Since the first liquid and the second liquid separate from each other and the second liquid flows in the first space or the second space, the second liquid can be collected in the lower stream. [0028] Therefore, the second liquid can be separated from the mixed first and second liquids in the microarea. [0029] In the above method, the microstructure is constituted suitably, so that one of the first and second liquids can be allowed to easily flow relatively in the first space of the separated channel. For example, the microstructure contains a lot of elements, and a distance (gap) between the adjacent elements is not more than 10 μm. The microstructure may be made of a porous substance in which microholes are opened on all sides, or a fiber block. [0030] Preferably, the structure is a column-shaped structure which extends from the first space side to the second space side. [0031] A fluid which difficultly flows relatively in the first space of the first liquid and the second liquid can move easily along the extending direction of the microstructure towards the second space. Therefore, a separating efficiency of the liquid can be heightened. [0032] More preferably, one of the first liquid and second liquid contains water. The above structure undergoes a water-repellent treatment. In this case, the first or second liquid containing water repels the microstructure which underwent the water-repellent treatment so as to move to the second space, so that the liquid separating efficiency can be heightened. In the case where only one liquid of a mixed liquid composed of three or more liquids has water and affinity, the one liquid can be separated from the other liquids. [0033] Further, in order to solve the above first technical problem, the present invention provides an extracting apparatus which is basically characterized in that a first liquid space in which a first liquid is to flow in a layered state and a second liquid space in which a second liquid is to flow in a layered state are arranged so as to come in contact with each other in the layer direction. More concretely, the extracting apparatus is constituted in the following manner. [0034] The extracting apparatus incorporates a substance contained in the first liquid into the second liquid and extract the substance. The extracting apparatus has a channel and a separating section. The first liquid and the second liquid flow in the channel with them contacting alternately in not less than one or two laminar state, and the substance in the first laminar flow of the first liquid moves to the second laminar flow of the second liquid. The separating section is connected to a lower stream side of the channel and separates the second liquid from the first liquid. [0035] According to the above constitution, the first fluid and the second fluid are allowed to flow in a very small width of the channel so as to be capable of being in a laminar state. In the case of two or more first and second laminar flows, the first laminar flows and the second laminar flows are arranged alternately so as to come in contact with each other. [0036] Generally, the substance in the liquid diffuses voluntarily. Namely, molecules of a medium (liquid) continually collide with small matters (particles of the substance), and the small matters move in the medium irregularly. Due to this Brownian movement, the small matters diffuse in the medium. In the microarea, the relative interfacial area of the liquid becomes large (namely, a surface area becomes larger as compared with a volume), and the diffusion speed becomes abruptly high. For this reason, the particles of the substance in the first laminar flow move to the second laminar flow quickly. Namely, the particles are incorporated into the second liquid. In this case, it is preferable that the particles of the substance difficultly return from the second laminar flow to the first laminar flow, and for example, it is preferable that the substance is incorporated into the second liquid more easily than into the first liquid. When the substance is dioxin or the like, the first fluid can be water and the second fluid can be an organic solvent. Moreover, in order to diffuse the substance efficiently, it is preferable that the flow velocity of the first laminar flow is equal with the flow velocity of the second laminar flow and the flow velocities do not vary relatively. [0037] According to the above constitution, the flow of the laminar flow and the diffusion phenomenon of the particles in the channel are used, so that the substance contained in the first liquid can be incorporated into the second liquid efficiently in the microarea. [0038] In the separating section, only the second liquid is collected, so that the substance contained in the first liquid can be extracted. [0039] Preferably, in the channel, a width of one laminar flow is not more than 50 μm. When the width is not more than 50 μm, a Reynolds number becomes small, and the liquid can be easily transferred in the laminar state in the channel. [0040] The separating section can collect only the second liquid in the following various forms. [0041] Preferably the separating section includes a first branch channel in which the first laminar flow flows, and a second branch channel in which the second laminar flow flows. In this case, the channel is branched for each liquid in the laminar state, so that the second liquid can be separated from the first liquid easily. More preferably, a charging section, which charges a vicinity of an inlet of the first branch channel or the second branch channel is provided. [0042] According to the above constitution, in the case where the first liquid or the second liquid has polarity and the other one is nonpolar, one liquid having polarity is activated so as to enter the charged first branch channel or second branch channel, so that the liquid can be separated more efficiently. For example, nonpolar molecules such as petroleum ether, carbon tetrachloride, benzene, xylene, nitrobenzene and iodine can be separated from water having polarity. As for a mixed liquid composed of three or more liquids, in the case where only one liquid has polarity or where only one liquid is nonpolar, the one liquid can be separated from the other liquids. [0043] Further, in order to solve the above second technical problem, the present invention provides a separating apparatus having the following constitution. [0044] The separating apparatus separates the second liquid from the mixed first liquid and second liquid. The separating apparatus has a first space, a second space and a discharge port. The first space is provided with a microstructure, and one of the first liquid and the second liquid easily flows relatively. The second space extends along the first space and is connected to the first space. The discharge port is connected to a lower stream side of the first space or the second space where the second liquid flows, and the second liquid flows therein. [0045] According to the above constitution, when the mixed first and second liquids are allowed to flow in the first space and the second space, one of the first liquid and the second liquid which easily flows relatively in the first space flows in the first space, and the other liquid flows in the second space, so that the first liquid and the second liquid are separated from each other. For example, the structures undergo a hydrophilic treatment or a suitable functional group is provided, so that one of the first liquid and the second liquid can be allowed to easily flow in the first space relatively. Since the second liquid flows one of the first space or the second space, the second liquid can be collected from the discharge port. Therefore, the second liquid can be separated from the mixed first liquid and the second liquid in the microarea. [0046] In the above constitution, the microstructure is suitably constituted, so that one of the first liquid and the second liquid can be allowed to easily flow in the first space of the separated channel relatively. For example, the microstructure includes a lot of elements, and a distance (gap) between the adjacent elements is not more than 10 μm. The microstructure may be composed of a porous substance in which microholes are opened on all sides, or a fiber block. [0047] Preferably, the structure is a column-shaped structure which extends from the first space side to the second space side. [0048] A fluid which difficultly flows relatively in the first space of the first liquid and the second liquid can move easily along the extending direction of the microstructure towards the second space. Therefore, a separating efficiency of the liquid can be heightened. [0049] More preferably, one of the first liquid and second liquid contains water. The above structure undergoes a water-repellent treatment. [0050] According to the above constitution, the first or second liquid containing water repels the microstructure which has undergone the water-repellent treatment so as to move to the second space, so that the liquid separating efficiency can be heightened. In the case where only one liquid of a mixed liquid composed of three or more liquids has water and affinity, the one liquid can be separated from the other liquids. [0051] Further, in order to solve the above first technical problem, the present invention provides a chip for the extracting apparatus having the following constitution. [0052] The chip to be used for the extracting apparatus is used for the extracting apparatus which incorporates the substance contained in the first liquid into the second liquid so as to extracts the substance. The chip has a channel. The first liquid and the second liquid are transferred in the channel so as to come in contact with each other alternately in not less than one or two laminar state, and the substance in the first laminar flow of the first liquid can be moved into the second laminar flow of the second liquid. [0053] In the above constitution, the first fluid and the second fluid are allowed to flow in a very small width of the channel so as to be capable of being in the laminar state. In the case of two or more first laminar flows and second laminar flows, the first laminar flows and the second laminar flows are arranged alternately so as to be capable of being in contact with each other. [0054] Generally, the substance in the liquid diffuses voluntarily. Namely, molecules of a medium (liquid) continually collide with small matters (particles of the substance) in the medium, and the small matters move in the medium irregularly. Due to this Brownian movement, the small matters diffuse in the medium. In the microarea, the relative interfacial area of the liquid becomes large (namely, a surface area becomes larger as compared with a volume), and the diffusion speed becomes abruptly high. For this reason, the particles of the substance in the first laminar flow move to the second laminar flow quickly. Namely, the particles are incorporated into the second liquid. In this case, it is preferable that the particles of the substance difficultly returns from the second laminar flow to the first laminar flow, and for example, it is preferable that the substance is incorporated into the second liquid more easily than into the first liquid. When the substance is dioxin or the like, the first fluid can be water and the second fluid can be an organic solvent. Moreover, in order to diffuse the substance efficiently, it is preferable that the flow velocity of the first laminar flow is equal with the flow velocity of the second laminar flow and the flow velocities do not vary relatively. [0055] According to the above constitution, the flow of the laminar flows and the diffusion phenomenon of the particles in the channel are used, so that the substance contained in the first liquid can be incorporated into the second liquid efficiently in the microarea. [0056] Only the second liquid is collected, so that the substance contained in the first liquid can be extracted. [0057] Preferably, in the channel, a width of one laminar flow is not more than 50 μm. When the width is not more than 50 μm, a Reynolds number becomes small, and the liquid can be easily transferred in the laminar state in the channel. [0058] Preferably, a first branch channel and a second branch channel are provided. The first branch channel is connected to a lower stream side of the channel, and the first laminar flow flows therein. The second branch channel is connected to a lower stream side of the channel, and the second laminar flow flows therein. According to the above constitution, the channel is branched for each liquid in the laminar state, so that the second liquid can be separated from the first liquid easily. More preferably, a charging section, which charges a vicinity of an inlet of the first branch channel or the second branch channel is provided. [0059] According to the above constitution, in the case where the first liquid or the second liquid has polarity and the other one is nonpolar, one liquid having polarity is activated so as to enter the charged first branch channel or second branch channel, so that the liquid can be separated more efficiently. For example, nonpolar particles such as petroleum ether, carbon tetrachloride, benzene, xylene, nitrobenzene and iodine can be separated from water having polarity. As for a mixed liquid composed of three or more liquids, in the case where only one liquid has polarity or where only one liquid is nonpolar, the one liquid can be separated from the other liquids. [0060] Further, in order to solve the second technical problem, the present invention provides a chip for the separating apparatus having the following constitution. [0061] The chip for the separating apparatus is used for the separating apparatus which separates a second liquid from mixed first liquid and second liquid. The chip has a first space, a second space and a discharge port. The first space is provided with a microstructure, and one of the first liquid and the second liquid easily flows relatively. The second space extends along the first space and is connected to the first space. The discharge port is connected to a lower stream side of the first space or the second space where the second liquid flows, and the second liquid flows therein. [0062] According to the above constitution, when the mixed first and second liquids are allowed to flow in the channel, one of the first liquid and the second liquid which easily flows relatively in the first space flows in the first space, and the other liquid flows in the second space. For example, the structure undergoes a hydrophilic treatment or a suitable functional group is provided, so that one of the first liquid and the second liquid can be allowed to easily flow in the first space relatively. Since the first liquid and the second liquid are separated from each other and the second liquid flows in one of the first space and the second space, the second liquid can be collected on the lower stream side. [0063] Therefore, the second liquid can be separated from the mixed first liquid and the second liquid in the microarea. [0064] The microstructure is suitably constituted, so that one of the first liquid and the second liquid can be allowed to easily flow in the first space relatively. For example, the microstructure includes a lot of elements, and a distance (gap) between the adjacent elements is not more than 10 μm. The microstructure may be composed of a porous substance in which microholes are opened on all sides, or a fiber block. [0065] Preferably, the structure is a column-shaped structure which extends from the first space side to the second space side. [0066] According to the above constitution, a fluid which difficultly flows relatively in the first space of the first liquid and the second liquid can move easily along the extending direction of the microstructure towards the second space. Therefore, a separating efficiency of the liquids can be heightened. [0067] More preferably, one of the first liquid and second liquid contains water. The above structure undergoes a water-repellent treatment. [0068] According to the above constitution, the first or second liquid containing water repels the microstructure which has undergone the water-repellent treatment so as to move to the second space, so that the liquid separating efficiency can be heightened. In the case where only one liquid of a mixed liquid composed of three or more liquids has water and affinity, the one liquid can be separated from the other liquids. BRIEF DESCRIPTION OF THE DRAWINGS [0069] These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings in which: [0070] [0070]FIG. 1 is a schematic diagram showing a flow of a microarea; [0071] [0071]FIG. 2 is a schematic diagram showing movement of particles in the microarea; [0072] [0072]FIG. 3 is a graph showing a relationship among a channel width, a relative interfacial area and a diffusion speed; [0073] [0073]FIG. 4 is a main section perspective view of a pretreatment assembly according to a first embodiment of the present invention; [0074] [0074]FIG. 5 is an exploded perspective view of the pretreatment assembly; [0075] [0075]FIG. 6 is a top view of the pretreatment assembly; [0076] [0076]FIG. 7 is a main section exploded perspective view of the pretreatment assembly according to a second embodiment of the present invention; [0077] [0077]FIG. 8 is a main section enlarged perspective diagram of the pretreatment assembly; [0078] [0078]FIG. 9 is a structural diagram of divided channels according to a modified example; and [0079] [0079]FIG. 10 is a flowchart of the pretreatment step in a dioxin measurement. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0080] There will be explained below embodiments of the present invention with reference to FIGS. 1 to 10 . [0081] Firs of all, a first embodiment of the present invention will be explained with reference to FIGS. 1 to 6 and FIG. 10. [0082] [0082]FIG. 1 typically shows a flow of water and solvent in a microarea. Divided channels 10 a and 10 b , which are divided respectively into plural channels 13 a to 13 g and 15 a to 15 g by partition walls 12 and 14 , are formed on both ends of one center channel 10 without a partition so as to be opposed to each other. The solvent and the water flow alternately in one divided channel 10 a . For example, the solvent flows in the channels 13 a , 13 c , 13 e and 13 g and the water flows in the channels 13 b , 13 d and 13 f . A width of the respective channels 13 a to 13 g is, for example, 20 μm, and since a Reynolds number becomes small in such a microarea, the water and the solvent outflow from the divided channel 10 a become laminar flows 11 a and 11 b respectively in the center channel 10 , and if they are adjacent to each other, they flow without mixing, and interfaces 11 c are formed respectively between the water and the solvents. The laminar flows 11 a and 11 b flow into the channels 15 a to 15 g of the other divided channel 10 b . Namely, the solvent flows into the channels 15 a , 15 c , 15 e and 15 g , and the water flows into the channels 15 b , 15 d and 15 f. [0083] [0083]FIG. 2 typically shows movement of particles 16 a and 16 b of dioxin or the like in the liquid. In the divided channel 10 a , the particles 16 a are contained only in the water which flows in the channels 13 b , 13 d and 13 f but are not contained in the solvent which flows in the channels 13 a , 13 c , 13 e and 13 g . Just after outflowing to the center channel 10 , the particles 16 a are contained in water layers 11 a . The particles 16 a voluntarily diffuse in the liquid due to Brownian movement. At this time, as shown by arrows 17 , the particles 16 b which exceed interfaces 11 c and moves from the water layers 10 d to solvent layers 10 b hardly returns to the water layers 10 d due to a difference of solubility. Since a relative interfacial area of the liquid becomes large in the microarea and a diffusion speed abruptly becomes high, the particles 16 a in the water layers 11 a move to the solvent layers 11 b quickly. Therefore, if only the solvent layers 11 b are collected by using the divided channel 11 b , the particles 16 b can be extracted. [0084] [0084]FIG. 3 is one example of a graph of the channel width, the relative interfacial area S/V and the diffusion speed t. When the channel width becomes smaller than 50 μm, the diffusion time S abruptly becomes short and the diffusion speed becomes high. Therefore, when the channel width is not more than 50 μm, preferably not more than 20 μm, the mixing and extracting time can be shortened greatly. For example, this embodiment can be used in a blood clotting test which requires that a reagent should be mixed fast (within 1 second). [0085] FIGS. 4 to 6 show an embodiment in which the present invention is applied to a pretreatment assembly 50 for measuring dioxin. [0086] As shown in FIG. 4( a ), in order to allow a condensed dioxin solution and an organic solvent to flow into a layer form, channels 20 and 30 which cross three dimensionally are formed. [0087] The organic solvent flows in the channel 20 arranged in an upper section to a direction shown by an arrow 28 . As for the channel 20 , one main channel 21 branches into three branch channels 22 on a lower stream side, and drum-shaped down channels 24 are formed to face downward respectively from bottom faces of end sections 23 of the branch channels 22 . [0088] The condensed dioxin solution flows in an upper stream channel 31 of the channel 30 arranged in a lower section to a direction shown by an arrow 38 . Divided channels 32 are formed in the middle way of the channel 30 , and the organic solvent and the dioxin solution respectively flow in channels 34 and 35 which are formed alternately. Namely, plural pairs of partition walls 33 a are arranged with an interval. The respective paired partition walls 33 a extend to the channel direction and have a thickness of a several μm. Upper stream sides of the paired partition walls 33 a are combined by connecting walls 33 b . The organic solvent flows from the down channels 24 to the channels 34 between the paired partition walls 33 a , and the condensed dioxin solution flows from the upper stream channel 31 to the channels 35 between the paired adjacent partition walls 33 a. [0089] One laminar flow mixing channel 36 is formed on the lower stream side of the divided channels 32 , and the dioxin solution and the organic solvent flow in the laminar state in the laminar flow mixing channel 36 so that the dioxin dissolves in and is incorporated into the organic solvent layer. A width of the laminar flow mixing channel 36 is about 200 μm, and its height (up-and-down direction in the diagram) is about 100 μm. [0090] Meanwhile, as shown in FIG. 4( b ), divided channels 40 are formed on the lower stream side of the laminar flow mixing channel 36 so as to be opposite to the divided channels 32 , and the water and the organic solvent respectively flow in channels 44 and 45 formed alternately. [0091] Namely, plural pairs of partition walls 41 a are arranged with an interval. The respective paired partition walls 41 a extend to the channel direction, and their lower stream sides are combined by connecting walls 41 b . The organic solvent containing dioxin flows into the channels 44 between the paired partition walls 41 a , and the water from which the dioxin is removed flows in the channels 45 between the paired adjacent partition walls 41 a. [0092] Discharge channels 42 are formed on the lower stream side of the paired partition walls 41 a , and as shown by arrows 43 , the organic solvent containing the dioxin is sucked downward and treated at the next step. [0093] Meanwhile, after the water from which the dioxin is removed passes through the divided channel 40 , it flows in a channel 46 and, as shown by an arrow 48 , is sucked upward from an end section 47 of the channel. [0094] The channels 20 and 30 are formed in the pretreatment assembly 50 in a manner that a plurality of chips 51 to 60 , shown in FIG. 5, are laminated. In this specification, the pretreatment assembly 50 may be mentioned as a chip. [0095] The respective chips 51 to 60 can be created accurately, for example, by dry-etching silicon or glass using ICP (Inductively Coupled Plasma). Direct coupling is used for silicon-to-silicon coupling, and anode coupling is used for silicon-to-glass coupling, but the bonding may be carried out by epoxy adhesive. Moreover, a mold of the chip is formed by galvanoplasty using silicon or nickel, and a resin such as PMMA (polymethyl methacrylate) or PDMS (polydimethyl siloxane) is molded so that a lot of chips can be created at a low rate. In this case, it is necessary to coat the resin so that the resin does not react with the organic solvent. Moreover, not only the dry etching but also wet etching may be used as the etching of silicon and glass. [0096] The first layer chip 51 is formed with an inlet 51 a for supplying an exhaust gas sample containing dioxin or the like, an inlet 51 b for supplying the water, an inlet 51 c and a channel 20 for supplying the organic solvent, a through hole 51 f , a discharge port 51 d for discharging unnecessary water and a discharge port 51 e for discharging refined dioxin. [0097] The second layer chip 52 is formed with channels 52 s and 52 t in which the exhaust gas sample and the water supplied from the inlet 51 a and 51 b flow and interflow, a porous glass 52 f for collecting and condensing dioxin, and the channel 30 in which the collected and condensed dioxin solution flows. [0098] The third layer to tenth layer chips 53 to 60 are provided with a suitable reagent based on, for instance, Japanese Industrial Standards (JIS) in order to refine the dioxin using multi-layer silica chromatography. Namely, pursuant to the JIS, 53 g of sodium sulfate is contained in the third layer chip 53 , 54 g of 10 weight % silver nitrate is contained in the fourth layer chip 54 , 55 g of silica gel is contained in the fifth layer chip 55 , 56 g of 22 weight % silica gel sulfate is contained in the sixth layer chip 56 , 57 g of 44% by weight silica gel sulfate is contained in the seventh layer chip 57 , 58 g of silica gel is contained in the eighth layer chip 58 , 59 g of 2% by weight silica gel potassium hydroxide is contained in the ninth layer chip 59 , and 60 g of silica gel is contained in the tenth layer chip 60 . Of course, the reagents may be altered in accordance with the other standards. [0099] As shown in FIGS. 6 and 10, the exhaust gas sample and the water which have passed cylindrical filter paper are supplied to the inlets 51 a and 51 b of the pretreatment assembly 50 and pass through the channels 52 s and 52 t so as to be mixed (#1). The cylindrical filter paper is broken and the dioxin may be collected (#8) by soxhlet extraction using a solvent instead of water. [0100] The mixed solution of the dioxin and water passes through the porous glass 52 f , so that the dioxin is collected and condensed (#2). Namely, water vapor, carbon dioxide and nitrogen dioxide pass from the porous glass 52 f through the through hole 51 f of the chip 51 so as to be discharged. [0101] The water which contains the condensed dioxin or the like flows in the channel 30 . The organic solvent is supplied from the inlet 51 c so as to flow in the channel 20 . The organic solvent contains hexane, toluene, acetone, dichloromethane and HCL in at the suitable rate. The water containing the dioxin or the like and the organic solvent pass through the divided channel 32 so as to meet in the laminar flow mixing section 36 , and as mentioned above, the dioxin or the like is incorporated into the organic solvent (#3 in FIG. 10), so that the water and the organic solvent are separated in the divided channel 40 (#4 in FIG. 10). [0102] The unnecessary water is discharged from the upper discharge port 51 d. [0103] The organic solvent flows in the lower section and passes sequentially through the chips 53 to 60 provided with 53 g to 60 g of reagents and slightly mixed water is removed so that the dioxin is refined (#5 in FIG. 10). The refined dioxin is discharged from the upper outlet 51 e and is measured by GC/MS (gas chromatography/mass spectrograph). [0104] A second embodiment of the present invention will be explained below with reference to FIGS. 7, 8 and 10 . [0105] In the second embodiment, as shown by a reference numeral 90 in FIG. 10, instead that after the water and the organic solvent are mixed by the laminar flow, they are separated (#3 and #4), as shown by a reference numeral 92 , turbulence occurs so that the water and the organic solvent are mixed and thereafter separated (#6 and #7). [0106] The pretreatment assembly 70 to which the present invention is applied uses chips 71 , 72 and 73 shown in FIG. 7 instead of the chips 51 and 52 shown in FIG. 5. The chips 71 , 72 and 73 can be processed by the similar method to the chips 51 and 52 . [0107] Similarly to the chip 51 of the first embodiment, the first layer chip 71 is formed with an inlet 71 a for supplying an exhaust gas sample, an inlet 71 b for supplying water, an inlet 71 c for supplying an organic solvent, a through hole 71 f and a discharge port 71 d for discharging unnecessary water. [0108] Similarly to the chip 52 of the first embodiment, the third layer chip 73 is provided with channels 73 s and 73 t in which the exhaust gas sample and the water flow and interflow, and a porous glass 73 f for collecting and condensing the dioxin. [0109] Differently from the first embodiment, mixing spaces 74 for mixing the water containing the dioxin or the like and the organic solvent using turbulence are formed respectively between the first to third layer chips 71 to 73 . Moreover, a PZT layer 71 e is formed in an area opposed to the mixing spaces 74 on the upper surface of the first layer chip 71 . The PZT layer 71 e is divided into four sections, for example, and a voltage of suitable waveform is applied to the respective sections in a suitable order so that an ultrasonic is generated. As a result, eddy is generated in the mixing spaces 74 , so that the water containing the dioxin or the like and the organic solvent can be agitated and mixed. [0110] The mixed water and organic solvent passes from the mixing spaces 74 through a channel 75 formed on the third layer chip 73 , so that the water and the organic solvent are separated. [0111] As shown in FIG. 8, microstructure 76 is formed in the lower section of the channel 75 (namely, a first space). The microstructure 76 has a plurality of columns having a diameter of several μm to several dozen μm, and they extend from a bottom section 75 a of the channel 75 to the middle of the height direction of the channel 75 , and there is no obstruction in the upper section of the channel 75 (namely, a second space). A distance (gap) between the columns is, for example, not more than 10 μm. The microstructure 76 are not limited to in the form of the columns, and may be, for example, prisms or cones. Furthermore, the microstructure 76 may be made of a porous substance or a fiber block. [0112] The surfaces of the microstructures 76 undergo a water-repellent treatment. In the case where the microstructures 76 are formed by an ICP apparatus, since the working process uses C 4 F 8 gas, their surfaces undergo water-repellent process without special additional treatment. The surfaces may undergo the water-repellent treatment by adhering fluorine macromolecules to the surfaces by eutectoid plating or the like. [0113] The water of the mixed solution which has entered the microstructures 76 moves to the upper section of the channel 75 due to the water-repellent treatment of the microstructures 76 . Meanwhile, the organic solvent just flows in the lower section of the channel 75 . Moreover, the water and the organic solvent are separated to the upper section and the lower section of the channel 75 with the assistance of a difference in specific gravity. The microstructures 76 may be formed in the upper section of the channel 75 according to a difference in specific gravity. [0114] Thereafter, unnecessary water is sucked from a lower stream end section 75 b of the channel 75 to the upper section as shown by an arrow 77 . Meanwhile, the organic solvent is sucked from a discharge port 75 c formed on the bottom face of the lower stream end section 75 b to the lower section as shown by an arrow 78 so as to flow into a refining section, not shown, (for example, it is composed similarly to the chips 53 to 60 ). [0115] As explained above, the flow of the laminar flow and the diffusion phenomenon of particles in the microarea are used, so that the dioxin can be extracted efficiently using a very small amount of a sample. Moreover, a second liquid can be separated from mixed first liquid and second liquid in the microarea. [0116] Therefore, since the treatment can be carried out in the microchips having a size of several cm×several cm, portableness is excellent, and the treatment can be executed immediately anywhere, so that the immediacy of the check is improved. Moreover, the reacting time is fast and the treatment time is shortened, so that the cost can be reduced greatly. Further, since an amount of the organic solvent to be used for the extraction is greatly smaller than conventional methods, the method of the present invention is environmental friendly. Since the chip can be mass produced by utilizing a semiconductor process or the like, the unit price is very low. Since the unit price of the chip is low, the chip can be disposable. When the chip is disposable, unlike in the case where the chip is used plural times, the problem of pollution due to waste water does not arise and troublesome cleaning is not required. [0117] The present invention is not limited to the above embodiments, and the invention can be carried out in another various forms. [0118] For example as shown in FIG. 9, a partition wall 80 of the divided channel 10 b is charged positively or negatively, so that the water and the organic solvent can be separated. As for the partition wall 80 , main body sections 82 are formed by an insulating substance, and electrodes 83 a and 83 b are provided on side faces of the main body sections 82 opposed to the channels 15 a to 15 g , so that outermost layers 84 are covered with the insulating substance. For example, SiO 2 or the like is deposited as an insulating film on the surfaces of the electrodes 83 a and 83 b . The electrodes 83 a and 83 b are connected with a power source 85 so as to be charged positively or negatively. At this time, as shown in the diagram, the electrodes 83 a and 83 b which are countered to each other via the channels 15 a to 15 g have the same potential, so that the channels 15 a to 15 g are charged positively or negatively in an alternate manner. [0119] Since water is polar molecule and is always charged positively, it does not enter an area charged positively. In order that the water is easily influenced by electric charge, the width of the channels 15 a to 15 g is not more than 50 μm. Not more than 10 μm is preferable. [0120] Further, the present invention can be applied not only to the pretreatment for the measurement of dioxin but also to a wide range. If the present invention is applied, in the case where an organic substance which dissolves or flows in water is extracted, a slight amount of a sample solution and an extracting solvent are mixed and the extracting solvent containing the organic substance can be selectively extracted. [0121] Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein.

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sprocket assembly used for the transmission of power, such as conveyors, and, more particularly, to an assembly in which both the sprocket and the hub have a split design to allow easier installation and removal thereof. 2. Background Art Power transmitting sprocket and hub assemblies have been use in the art for years. An example is U.S. Pat. No. 2,714,820, issued to Chamberlain in 1955, which discloses a hub and a replaceable sprocket attached to the hub. The Chamberlain patent discloses two different systems for attaching the replaceable sprockets to the hub: (1) a sprocket having a threaded bore that complementarily engages the threaded outer diameter of the hub and (2) a sprocket having a bore that slidably engages the outer diameter of the hub and that is securably attached to the flange of the hub by a plurality of bolts. A problem with this design is that if the sprocket or hub is blocked from freely sliding off the supporting shaft, then removal of the components is difficult. That is, changing a sprocket or a hub on shafts with several other sprockets or support bearings is time consuming and expensive. A frequent problem is that bearings which have supported the shaft for several years are easily damaged during this process. An improvement in the art is disclosed in U.S. Pat. No. 4,964,842, issued to Howard in 1990, which teaches a split sprocket. The Howard patent, however, does not address the hub assembly. Thus, a need exists in the art for an assembly in which both the sprocket and the hub are easily removable from a shaft. Such an improvement would facilitate the removal of either or both components, which is sometimes required in use. An example is "turning" (reversing on the shaft) the sprocket and hub wherein a new wearing surface of the sprocket's teeth is brought into contact with the chain or other component through which power transmission occurs. Another need in the art is a means to precisely align the hub and sprocket with each other. That is, if a hub and sprocket are used which can be assembled around a shaft without requiring dismantling the shaft or adjacent sprockets, then the components need to be joined together to ensure proper alignment and prevent separation. SUMMARY OF THE INVENTION The above disadvantages of the prior art are satisfied by the present invention, which comprises a split sprocket, a split hub, and a means for coupling the split sprocket to the split hub. A pair of sprocket segments form the split sprocket and a pair of hub segments form the split hub. The split sprocket defines a sprocket bore which is axially tapered so that the diameter of the sprocket bore adjacent one side of the split sprocket is larger than the diameter of the sprocket bore adjacent its other side. The split hub has an external surface and defines a hub bore. The hub bore is of a size to be disposed around a shaft so that the split hub maintains a constant radial position relative to the shaft. In addition, at least a portion of the external surface of the split hub can be complementarily received within the tapered sprocket bore. The coupling means couples the split sprocket to the split hub so that the tapered sprocket bore matingly engages the tapered portion of external surface of the hub. When coupled together, the sprocket segments and hub segments are self-aligning to ensure a secure fit without lineup problems. The split hub preferably also has a flange having a plurality of passages extending through it. The split sprocket similarly defines a plurality of openings, in which each opening is in registry with a respective passage. The coupling means comprises a plurality of fasteners extending through the passages in the flange and a means for engagably mating each fastener to the respective opening in the split sprocket. The fasteners couple the flange of the split hub to the split sprocket. The fasteners preferably are a reusable, locking type that will not work loose. The present invention can also use a key to maintain the radial position between the shaft hub assembly and the shaft. A portion of the key is disposed both in a groove in the hub bore and in a channel in the shaft, or shaft keyway. The key is captive, or completely surrounded by the split hub assembly and the shaft, and cannot escape unless the split hub is disassembled. As one skilled in the art will appreciate, a key cannot be "captive" in a prior art, non-split hub. A captive key has practical advantages over the prior art, such as preventing the key from working loose and sliding out the end of the hub bore. Losing a key would likely disable the sprocket and, if not discovered quickly, cause substantial wear between the sprocket bore and the mating surface of the shaft. Power would be lost to the chain being driven by the prior art sprocket without a key. Another potential problem is that a different conveyor is often located underneath the shaft so that an errant key could damage other machinery. Another advantage of the present invention is that a key of an appropriate length captive in the hub assures that the sprocket cannot "walk" or migrate along the length of the shaft. Set screws are not needed with the present invention. Accordingly, there is no danger of set screws working loose and falling onto other conveyors with the resulting problematic consequences. The present invention provides many other advantages over the prior art. Installation and removal of the split hub assembly are drastically easier. For example, reversing conventional sprockets on shafts with several sprockets and several bearings is time consuming and expensive. A frequent problem is that the bearings are damaged and must be replaced when they are being stripped from a shaft that has been in service for several years. The present invention allows installation and removal of the split hub and split sprocket without contacting or removing the bearings by demounting the shaft. The split hub assembly of the present invention is desirable because split sprockets can easily be "turned." The "turned" sprockets orient a new wearing surface of the teeth onto contact with the chain approximately doubling the sprocket life. Turning the split sprocket of the present invention is much easier than using the prior art sprockets. Also, the split hub does not wear and can be used repeatedly so that only the split sprocket requires periodic replacement. Components of the present invention can be smaller and lighter than prior art sprockets. The present invention is also easier to handle, which is helpful in constricted or awkward locations, such as under log decks, on elevator head shafts, and the like. BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS FIG. 1 is a perspective view of the preferred embodiment of the present invention assembled and disposed on a shaft. FIG. 2 is an exploded perspective view of FIG. 1 showing the unassembled components of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to one skilled in the art. As used in the specification and in the claims, "a" can mean one or more, depending upon the context in which it is used. Referring to FIGS. 1 and 2, the present invention is a split hub assembly 10 comprising a split sprocket 20, a split hub 40, and a means for coupling the split sprocket 20 to the split hub 40. A plurality of sprocket segments 22 forms the split sprocket 20, which is rotatable about its radial axis R. The split sprocket 20 has a first side 26, an opposed second side 28, and an engaging surface 30, which engages a chain (not shown) or similar component. The split sprocket 20 defines a sprocket bore 32 (FIG. 2) having a longitudinal axis that is coaxial with the radial axis R of the split sprocket 20. The sprocket bore 32 extends from the first side 26 to the second side 28 of the split sprocket 20 and is axially tapered so that the diameter of the sprocket bore 32 adjacent the first side 26 is larger than the diameter of the sprocket bore 32 adjacent its second side 28. Although more sprocket segments 22 can be used, it is preferred to use two segments to form the split sprocket 20 for manufacturing and installation considerations. The present invention also comprises a means for connecting the sprocket segments 22 to each other to form the split sprocket 20. Preferably, each sprocket segment 22 has two edges 24, in which each edge 24 is in opposed relationship to the edge 24 of another sprocket segment 22 when the split sprocket 20 is formed. The preferred connecting means comprises a first connecting segment 60 that is disposed adjacent one edge 24 of each sprocket segment 22, a second connecting segment 62 that is disposed adjacent the other edge 24 of each sprocket segment 22 and in registry with one first connecting segment 60, and a means for detachably securing the first connecting segment 60 to the second connecting segment 62. The first connecting segment 60 preferably matingly engages the second sprocket segment 22, as shown in FIG. 2. As one skilled in the art will appreciate, other connecting means can be used, such as bands (not shown), connecting plates (not shown), and the like which secure the sprocket segments 22 to each other. The first and second connecting segments 60, 62 of the preferred connecting means are constructed from round bar. The mating ends of the segments 60, 62 have a male taper 64 on one segment and a female taper 66 on the other segment. During construction, the segments 60, 62 are temporarily secured to each other and the assembly is positioned so that the first and second connecting segments 60, 62 are each disposed adjacent the edge 24 of a respective sprocket segment 22. The first and second segments 60, 62 are then welded in this position to the sprocket segments 22 in a jig (not shown). When the sprocket segments 22 are separated, the welded connecting segments 60, 62 can later be aligned in the field so that the split sprocket 20 and its bore 32 are perfectly formed. The detachably securing means used to connect the first and second segments preferably comprises a bolt 70 and a nut 76. The bolt 70 has a top end 72 and an opposed bottom end 74 and is disposed through both the first and second connecting segments 60, 62. The nut 76 complementarily engages a portion of the bolt 70 adjacent its bottom end 74 so that the first and second connecting segments 60, 62 are disposed intermediate the top end 72 of the bolt 70 and the nut 76. Thus, the nut 76 and the bolt 70 maintain the first and second connecting segments 60, 62 in an engaged relationship with each other. The present invention also comprises a plurality of hub segments 42 that form the split hub 40. The split hub 40 is rotatable about a radial axis, preferably the same as the split sprocket's 20 radial axis R. As with the sprocket segments 22, preferably two hub segments 42 are used, although using more segments is an option. The split hub 40 has an external surface 44 and defines a hub bore 50 extending therethrough. The hub bore 50 has a longitudinal axis which is coaxial with the radial axis R of the split hub 40 and is of a size to be disposed around a shaft 80 so that the split hub 40 maintains a constant radial position relative to the shaft 80. At least a portion of the external surface 44 of the split hub 40 is tapered to be complementarily received within the tapered sprocket bore 32. The tapered external surface 44, accordingly, has a wide end 46 and an opposite narrow end 48. The coupling means positions the hub segments 42 to each other to form the split hub 40. The coupling means also couples the split sprocket 20 to the split hub 40 so that the tapered sprocket bore 32 matingly engages the tapered portion of the hub, whereby the split sprocket 20 is securely connected to the split hub 40. When coupled together, the first side 26 of the split sprocket 20 is disposed adjacent the wide end 46 of the external surface 44 of the split hub 40. Preferably, the split hub 40 also has a flange 54 extending therefrom which is located adjacent the wide end 46 of the external surface 44 of the split hub 40. The flange 54 defines a plurality of passages 56 therethrough. In conjunction, the split sprocket 20 defines a plurality of openings 34, in which each opening 34 is in registry with a respective passage 56. In the preferred embodiment, the coupling means comprises a plurality of fasteners 58 and a means for engagably mating each fastener 58 to a respective opening 34 in the split sprocket 20. Each fastener 58 extends through a passage 56 in the flange 54 and into a respective opening 34 in the split sprocket 20 so that the fastener 58 couples the flange 54 to the split sprocket 20. As shown in FIG. 2, the preferred embodiment uses either six (6) or eight (8) threaded fasteners 58 that are disposed through the hub flange 54 and into drilled and tapped openings 34 in the split sprocket 20. As one skilled in the art will appreciate, the fasteners 58 can alternately extend through the openings 34 in the split sprocket 20 and engagably mate with a nut (not shown) or other similar component, instead of mating with complementarily threaded openings 34 in the split sprocket 20. The fasteners 58 preferably are cap screws, specifically a "WIZ-LOC"® manufactured by McClain-Fogg, Inc., or a similar type that is plated to prevent rusting and seizing. The preferred cap screws also have a serrated washer (not shown) that is forged as an integral part of its head. This type fastener 58 does not require a separate, removable washer, which is a convenience in field assembly. More importantly, when properly tightened, the fasteners 58 and integral washer combinations will not work loose, which is important in bulk handling facilities, such as paper mills. As one skilled in the art will appreciate, lost fasteners 58 or washers can reach the mill and result in detrimental and expensive consequences. To install the present invention, the hub segments 42 are placed around the shaft 80 to form the split hub 40 and the tapered sprocket bore 32 of the split sprocket 20 is disposed over the tapered portion of the external surface 44 of the split hub 40. The fasteners 58 are fitted through the passages 56 in the flange 54 and screwed into the openings 34 in the assembled split sprocket 20. The fasteners 58 are then equally tightened to draw the split sprocket 20 evenly onto the tapered portion of the split hub 40. The machinist applies sufficient torque to each fastener 58 to ensure that the split sprocket 20 tightly fits on the split hub 40 so that the split sprocket 20 is locked in position and will not slip on the split hub 40 under a load. The tapered bore of the split sprocket 20 and the tapered portion of the external surface 44 of the hub should fit together within exacting tolerances. The alignment between the split sprocket 20 and the hub segments 42 of the split hub 40 is important to ensure optimal performance. The split sprocket 20, which is disposed over a portion of the exterior surface of the split hub 40, maintains the hub segments 42 in the correct alignment. The "force-fit" design using the complementarily tapered shapes provides an extremely tight fit on the shaft 80, eliminating the possibility of the sprocket "walking" along the length of the shaft 80 or undesirable radial movement relative to the shaft 80. For removal, the fasteners 58 can be "broken loose" by the application of sufficient force and they can be used again. Proper installation of the split sprocket 20 on the split hub 40 creates sufficient friction between the split hub 40 and the shaft 80 that little likelihood of relative movement exists. Nevertheless, a key 90 is used in the preferred embodiment to ensure the alignment is maintained. The hub bore 50 preferably defines an axially-extending groove 52 therein and the shaft 80 defines a channel 82, wherein the key 90 is disposed therebetween. The key 90 ensures that the split hub 40 is radially fixed relative to the shaft 80. Preferably, the manufacturer can mill the groove 52 and channel 82, or keyway, long enough to carry the torque load between the split hub 40 and the shaft 80, but the keyway does not have to extend to the wide end 46 or narrow end 48 of the hub bore 50. The keyway thus is closed at both ends so the key 90 is captured, or completely surrounded. The key 90 is placed in its position before assembly of the split hub 40 and is trapped there. The key 90 cannot work loose and fall out. In contrast, loss of the key from a prior art device will usually result in the sprocket freely turning on the shaft 80. The lost key may also result in equipment damage. Due to the high friction between the shaft 80 and split hub 40, set screws (not shown) are not required. Therefore, there are no set screws to work loose and fall into chip conveyors or other material streams where they might cause damage to machinery. An optional feature of the present invention is that the split sprocket 20 is engagable with slotted bolt holes in the hub (not shown). On multi-strand lugged transfer decks, this allows accurate alignment and is also helpful for other precision timing functions. Another advantage of the present invention is that since both the hub 40 and the sprocket 20 are split, they can easily be installed or removed. The split sprocket 20 of the present invention, moreover, can be installed in place on the shaft without the time-consuming and expensive process of demounting the shaft and stripping sprockets and bearings required with the prior art devices. That is, replacement of a prior art sprocket on a long shaft with several other sprockets and bearings requires the worn or damages sprocket to be slid, if space permits, along the shaft out of operative position. The split hub assembly of the present invention can then be installed in its place. If space is not available to slide the existing prior art sprocket out of the way, the sprocket can be cut off of the shaft and then the present invention can be installed. The present invention avoids the damage that can occur when bearings are stripped from the shaft. Because most sprockets in the field run primarily in one direction, some mills and other users of these components have found that timely reversal of sprockets on the shaft brings the unworn side of the sprocket teeth into contact with the chain. The life of a sprocket can be extended up to 100% by "turning" in this manner. Another aspect of the present invention is that, within a given shaft diameter range, split sprockets 20 of different sizes can be constructed to be interchangeable with a single split hub 40. Also, different split sprockets can engage different sizes of chain and use a different number of teeth. The interchangeable split sprockets allow mills to have a replacement supply of sprockets for when changes are required. Thus, a relatively small investment in assorted split hubs that fit different shaft sizes and assorted split sprockets provides "on hand" protection against downtime that can result from unexpected sprocket failure. Preferably, all components of the present invention are constructed of steel and all fasteners are heat-treated. The hub segments, sprocket segments, and other components are not required to be hardened, but flame hardening or carburizing may be desired, depending on the environment in which the components are used. Other options include constructing the components of special alloys, using either a double/single sprocket design on each split hub, and using a hunting tooth design on the split sprockets. The present invention has been discussed in terms of operating with a chain. However, as one skilled in the art will appreciate, the present invention can be applied to other devices, such as V-sheaves, pulleys, gears, brake components, and other rotating devices. Although the present invention has been described with reference to specific details of certain embodiments thereof, it is not intended that such details should be regarded as limitations upon the scope of the invention except as and to the extent that they are included in the accompanying claims.

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CROSS REFERENCE TO RELATED APPLICATION The present application is a divisional of U.S. patent application Ser. No. 09/901,425, filed Jul. 9. 2001, now U.S. Pat. No. 7,056,533 which itself claims the benefit of provisional U.S. patent application filed 15 Aug. 2000 and assigned Ser. No. 60/225,465, the entire disclosure of each of which is incorporated herein by reference. GOVERNMENT FUNDING The United States government may have certain rights in this invention by virtue of NIH Grant No. 1 R43 AR 44758-01. TECHNICAL FIELD In one aspect, the present invention relates to the delivery of medicaments, such as drugs, from within or upon the surface of implantable medical devices. In another aspect, the invention relates to hydrogel matrices containing these and other medicaments. BACKGROUND OF THE INVENTION Hydrogels are typically described as hydrophilic polymer networks that are capable of absorbing large amounts of water, yet are themselves insoluble because of the presence of physical or chemical crosslinks, entanglements or crystalline regions. Hydrogels have found extensive use in biomedical applications, including as coatings and drug delivery systems. Hydrogels are often sensitive to the conditions of their surrounding environment, such that the swelling ratio of the materials can be affected by temperature, pH, ionic strength and/or the presence of a swelling agent. Several parameters can be used to define or characterize hydrogels, including the swelling ratio under changing conditions, the permeability coefficient of certain solutes, and the mechanical behavior of the hydrogel under conditions of its intended use. When used as drug delivery systems these changes in the environment can often be controlled or predicted in order to regulate drug release. (See Bell and Peppas, cited below). A particular type of hydrogel that has been described in recent years involves the combination of poly(methacrylic acid) (“PMAA”) backbones and polyethylene glycol (“PEG”) grafts. For instance, Mathur, et al., J. Controlled Release 54(2):177-184 (1998) describe “responsive” hydrogel networks of this type. The hydrogels exhibit swelling transitions, in various solvent systems, and in response to external stimuli. These transitions, in turn, can lead to the formation or disruption of hydrogen-bonded complexes between the backbone and graft portions. The article describes the role of hydrophobic interactions in stabilizing the complexes. A variety of references further describe the preparation and use of hydrogels for the delivery of medicaments, including those hydrogels based on the combination of polyalkylene glycols and poly(meth)acrylates. See, for instance, U.S. Pat. Nos. 5,884,039 and 5,739,210, which describe polymers having reversible hydrophobic functionalities, e.g., polymers having Lewis acid and Lewis base segments. The segments are hydrophilic and will either swell or dissolve in water. When incorporated into a polymer, the segments form water-insoluble or hydrophobic complexes. Upon changes in pH, temperature or solvent type, the complexes can dissociate, giving large transitions in viscosity, emulsification ability and mechanical strength. The polymers are said to be useful as reversible emulsifiers, super-absorbing resins, or as coatings for pharmaceutical agents. See also, Scott, et al., Biomaterials 20(15):1371-1380 (1999), which describes the preparation of ionizable polymer networks prepared from oligo(ethylene glycol) multiacrylates and acrylic acid using bulk photopolymerization techniques. The networks are described for use in the preparation of controlled release devices for solutes. Finally, C. L. Bell, and N. A. Peppas, J. Biomater. Sci. Polymer Edn. 7(8):671-683 (1996) and C. L. Bell and N. A. Peppas, Biomaterials 17:1203-1218 (1996) each describe the synthesis and properties of grafted P(MAA-g-EG) copolymers. The copolymers permit the reversible formation of complexes under appropriate conditions due to hydrogen bonding between the carboxylic acid groups of the PMAA and the oxygen atoms of the PEG chains, resulting in pH-sensitive swelling behavior. Complexation occurs at low pH, resulting in increased hydrophobicity in the polymer network. At higher pH values, the acid groups become ionized and the hydrogen bonding breaks down. The papers studied this pH sensitive swelling behavior in relation to the use of such materials in controlled release drug delivery and bioseparations. The Bell and Peppas papers exemplified the swelling behavior of P(MAA-g-EG) samples containing 40:60, 50:50 and 60:40 ratios (weight percent) of PMAA:PEG, using PEG grafts having molecular weights of 200, 400 and 1000. The resultant hydrogels were evaluated by several means, including mechanical testing to determine shear modulus. The authors found that as the molecular weight of the PEG graft was increased, the modulus of the networks decreased in both the complexed and uncomplexed state. When used for drug delivery, the materials prepared by Bell and Peppas were typically used as free standing hydrogel membranes, with no mention of their use upon a surface, let alone the surface of an implanted medical device. Nor, in turn, do these references provide any suggestion of the manner in which such matricies might be applied to any such surface. Those references that do describe the delivery of medicaments from implanted devices tend to rely on approaches quite different from implanted hydrogels. The continuing development and use of implantable medical devices has led to the corresponding development of a variety of ways to deliver antibiotics and/or antiseptics to the implant site, in order to prevent potential infections associated with such devices. For instance, a significant percent of fracture fixation devices (pins, nails, screws, etc.) and orthopedic joint implants become infected. Cure of infected orthopedic implants, such as joint prostheses, usually requires both removal of the prosthesis and administration of a long course of antibiotics. In most cases, this is followed by re-implantation of a new joint prosthesis weeks or months later, after making sure that the infection has been eradicated. As described in the patents to Darouiche, cited below, considerable amount of attention and study has therefore been directed toward preventing colonization of bacterial and fungal organisms on the surfaces of orthopedic implants by the use of antimicrobial agents, such as antibiotics, bound to the surface of the materials employed in such devices. The objective of such attempts has been to produce a sufficient bacteriostatic or bactericidal action to prevent colonization. Various methods have previously been employed to coat the surfaces of medical devices with an antibiotic. For example, one method involves applying or absorbing to the surface of the medical device a layer of surfactant, such as tridodecylmethyl ammonium chloride (“TDMAC”) followed by an antibiotic coating layer. A further method known to coat the surface of medical devices with antibiotics involves first coating the selected surfaces with benzalkonium chloride followed by ionic bonding of the antibiotic composition. See, e.g., Solomon, D. D. and Sheretz, R. J., J. Controlled Release, 6:343-352 (1987) and U.S. Pat. No. 4,442,133. Yet other methods of coating surfaces of medical devices with antibiotics are taught in U.S. Pat. No. 4,895,566 (a medical device substrate carrying a negatively charged group having a pK of less than 6 and a cationic antibiotic bound to the negatively charged group); U.S. Pat. No. 4,917,686 (antibiotics are dissolved in a swelling agent which is absorbed into the matrix of the surface material of the medical device); U.S. Pat. No. 4,107,121 (constructing the medical device with ionogenic hydrogels, which thereafter absorb or ionically bind antibiotics); U.S. Pat. No. 5,013,306 (laminating an antibiotic to a polymeric surface layer of a medical device); and U.S. Pat. No. 4,952,419 (applying a film of silicone oil to the surface of an implant and then contacting the silicone film bearing surface with antibiotic powders). See also Ding et al., (U.S. Pat. No. 6,042,875), which describes a coating that permits timed or prolonged pharmacological activity on the surface of medical devices through a reservoir concept. Specifically, the coating comprises at least two layers: an outer layer containing at least one drug-ionic surfactant complex overlying a reservoir layer or tie layer containing a polymer and the drug which is substantially free of an ionic surfactant. Upon exposure to body tissue of a medical device covered with such coating, the ionically complexed drug in the outer layer is released into body fluid or tissue. Following release of such complexed drug, the ionic surfactant complex sites in the outer layer are left vacant. After insertion of a medical device such as an orthopedic implant, the antibiotics and/or antiseptics quickly leach from the surface of the device into the surrounding environment. Over a relatively short period of time, the amount of antibiotics and/or antiseptics present on the surface decreases to a point where the protection against bacterial and fungal organisms is no longer effective. Furthermore, during implantation of orthopedic fracture fixation devices, such as intramedullary nails and external fixation pins, much of the antimicrobial coating sloughs off due to grating of the coated implant against the bone during insertion of the implant. Hence, for some implants, and particularly those that both remain in the body for extended periods of time and that undergo tortuous processing in the course of their implantation or use, medicament coatings continue to be sought to provide improved durability. U.S. Pat. No. 5,853,745 (Darouiche), describes a durable antimicrobial coated orthopedic device or other medical implant having a durable material layer that decreases the rate of leaching of antimicrobial agents into the surrounding environment. The patent provides an antimicrobial coated medical implant or orthopedic device having mechanical resiliency to minimize or avoid sloughing of the antimicrobial layer from the device during insertion. The medical implant has one or more of its surfaces coated with a composition comprising an antimicrobial coating layer comprising an antimicrobial agent in an effective concentration to inhibit the growth of bacterial and fungal organisms, and a protective coating layer formed over said antimicrobial coating layer. When used as drug release coatings on devices, however, the various systems described above suffer from several drawbacks, e.g., in terms of the thickness of the coatings necessary to provide suitable amounts of drug, the kinetics (e.g., overall period of release), and the durability or tenacity of the coating itself. In spite of the various attempts and progress made to date, it remains clear that the need for a coating composition that provides an optimal combination of such properties as coating thickness, drug release profile, durability, swellability, generic applicability, and surface independence remains unmet. Improved coatings for use on implanted devices, in order to provide medicament release in situ, are clearly needed. SUMMARY OF THE INVENTION The present invention provides a crosslinkable coating composition, in both its uncrosslinked and crosslinked forms, for use in delivering a medicament from the surface of a medical device positioned in vivo. Once crosslinked, the coating composition provides a gel matrix adapted to contain the medicament in a form that permits the medicament to be released from the matrix in a prolonged, controlled, predictable and effective manner in vivo. The combination of gel matrix and medicament can be provided in any suitable manner and at any suitable time, e.g., the medicament can be included in one or more components of the uncrosslinked composition and/or it can be incorporated into the formed or forming matrix, e.g., at the time of use, and before, during, or after crosslinking the composition or implanting the thus-coated device into a tissue site. When applied as a coating to the surface of a medical device, a gel matrix can be formed thereon by a process that includes a complexation reaction between carboxylic acid groups and ether groups. The complexation reaction serves to both improve the durability and tenacity of the coating and prolong the delivery of the medicaments incorporated into the matrix. In a preferred embodiment, the coating composition preferably comprises a polymeric reagent formed by the polymerization of the following monomers: a) about 1 to about 20 mole % of a polyether monomer, b) about 5 to about 75 mole % of a carboxylic acid-containing monomer, such that the effective ratio of ether groups to carboxylic acid groups in the resultant copolymer is between about 1 to 1 and about 10 to 1, c) optionally, about 0.1 to about 10 mole % of a photoderivatized monomer, and d) an amount of a hydrophilic monomer suitable to bring the composition to 100% (e.g., about 0 to about 93.9 mole % of a hydrophilic monomer). When the polymeric reagent is applied as a coating to the surface of a medical device, noncovalent interactions occur between carboxylic acid groups and ether groups, thus contributing to the formation of a gel matrix. The application of UV light provides photochemical attachment to the substrate as well as the formation of covalent crosslinks within the matrix. The matrix, thus formed, provides both improved durability and tenacity of the coating in a manner that prolongs the delivery of the medicaments incorporated into the matrix. In a particularly preferred embodiment, for instance, the uncrosslinked composition comprises a polymeric reagent formed by the polymerization of the following monomers: a) methoxy poly(ethylene glycolmethacrylate) (“methoxyPEGMA”), as the polyether monomer, in an amount of between about 5 and about 15 mole %, b) (meth)acrylic acid, as the carboxylic acid-containing monomer component, present in an amount of between about 30 and about 50 mole %, c) photoderivatized monomer, present in an amount of between about 1 to about 7 mole %, and d) acrylamide monomer, as a hydrophilic monomer, present in an amount of between about 30 and about 70 mole %. Without intending to be bound by theory, it is believed that upon application of a solution of the uncrosslinked composition to the surface of a medical device, and UV illumination to activate the photogroups, that a covalently bound matrix is thus formed on the surface of the device. This matrix contains both carboxylic acid groups and ether groups which, under the appropriate conditions, form complexes. These complexes, in turn, increase the hydrophobicity of the matrix and appear to improve the durability and tenacity of the matrix, and prolong the release of the medicaments incorporated into the matrix. A matrix of this invention provides an optimal and improved combination of such properties as medicament release profile, durability, tenacity, solubility, swellability, and coating thickness. Such a matrix can be used with a wide range of surface materials and configurations, and in turn, is widely applicable and useful with a variety of implanted devices. DETAILED DESCRIPTION The composition of this invention preferably includes between about 1 and about 20 mole % of a polyether monomer and preferably from about 5 to about 15 mole %. Most preferably, the polyether monomer is used at a final concentration of about 8 to about 12 mole %. The term “mole %” as used herein will be determined by the molecular weight of the monomer components. The polyether monomer is preferably of the group of molecules referred to as alkoxy (poly)alkyleneglycol (meth)acrylates. The alkoxy substituents of this group may be selected from the group consisting of methoxy, ethoxy, propoxy, and butoxy. The (poly)alkylene glycol component of the molecule may be selected from the group consisting of (poly)propylene glycol and (poly)ethylene glycol. The (poly)alkylene glycol component preferably has a nominal weight average molecular weight ranging from about 200 g/mole to about 2000 g/mole, and ideally from about 800 g/mole to about 1200 g/mole. Examples of preferred polyether monomers include methoxy PEG methacrylates, PEG methacrylates, and (poly)propylene glycol methacrylates. Such polyether monomers are commercially available, for instance, from Polysciences, Inc., (Warrington, Pa.). A composition of this invention preferably includes between about 5 to about 75 mole % of a carboxylic acid-containing monomer, such that the effective ratio of ether groups to carboxylic acid groups in the resultant copolymer is between about 1 to 1 and about 10 to 1. Preferred concentrations of the carboxylic acid-containing monomer are between about 30 to about 50 mole %. Most preferably, the carboxylic acid-containing monomer is used at a concentration between about 30 to about 40 mole %. These monomers can be obtained commercially, for instance, from Sigma-Aldrich, Inc. (St. Louis, Mo.). Preferred carboxylic acid-containing monomers are selected from carboxyl substituted ethylene compounds, also known as alkenoic acids. Examples of particularly preferred carboxylic acid-containing monomers include acrylic, methacrylic, maleic, crotonic, itaconic, and citraconic acid. Most preferred examples of carboxylic acid-containing monomers include acrylic acid and methacrylic acid. A composition of the present invention preferably includes between about 0.1 and about 10 mole % of a photoderivatized monomer, more preferably between about 1 and about 7 mole %, and most preferably between about 3 and about 5 mole %. Examples of suitable photoderivatized monomers are ethylenically substituted photoactivatable moieties which include N-[3-(4-benzoylbenzoamido)propyl]methacrylamide (“BBA-APMA”), 4(2-acryloxyethoxy)-2-hydroxybenzophenone, 4-methacryloxy-2-hydroxybenzophenone, 4-methacryloxy-2-hydroxybenzophenone, 9-vinyl anthracene, and 9-anthracenylmethyl methacrylate. An example of a preferred photoderivatized monomer is BBA-APMA. Photoreactive species are defined herein, and preferred species are sufficiently stable to be stored under conditions in which they retain such properties. See, e.g., U.S. Pat. No. 5,002,582, the disclosure of which is incorporated herein by reference. Latent reactive groups can be chosen that are responsive to various portions of the electromagnetic spectrum, with those responsive to ultraviolet and visible portions of the spectrum (referred to herein as “photoreactive”) being particularly preferred. Photoreactive species respond to specific applied external stimuli to undergo active specie generation with resultant covalent bonding to an adjacent chemical structure, e.g., as provided by the same or a different molecule. Photoreactive species are those groups of atoms in a molecule whose covalent bonds remain unchanged under conditions of storage but upon activation by an external energy source, form covalent bonds with other molecules. The photoreactive species generate active species such as free radicals and particularly nitrenes, carbenes, and excited states of ketones upon absorption of electromagnetic energy. Photoreactive species can be chosen to be responsive to various portions of the electromagnetic spectrum, and photoreactive species that are responsive to, e.g., ultraviolet and visible portions of the spectrum, are preferred and can be referred to herein occasionally as “photochemical group” or “photogroup.” The photoreactive species in photoreactive aryl ketones are preferred, such as acetophenone, benzophenone, anthraquinone, anthrone, and anthrone-like heterocycles, i.e., heterocyclic analogs of anthrone such as those having N, O, or S in the 10-position, or their substituted, e.g., ring substituted, derivatives. Examples of preferred aryl ketones include heterocyclic derivatives of anthrone, including acridone, xanthone, and thioxanthone, and their ring substituted derivatives. Particularly preferred are thioxanthone, and its derivatives, having excitation energies greater than about 360 nm. The functional groups of such ketones are preferred since they are readily capable of undergoing the activation/inactivation/reactivation cycle described herein. Benzophenone is a particularly preferred photoreactive moiety, since it is capable of photochemical excitation with the initial formation of an excited singlet state that undergoes intersystem crossing to the triplet state. The excited triplet state can insert into carbon-hydrogen bonds by abstraction of a hydrogen atom (from a support surface, for example), thus creating a radical pair. Subsequent collapse of the radical pair leads to formation of a new carbon-carbon bond. If a reactive bond (e.g., carbon-hydrogen) is not available for bonding, the ultraviolet light-induced excitation of the benzophenone group is reversible and the molecule returns to ground state energy level upon removal of the energy source. Photoactivatible aryl ketones such as benzophenone and acetophenone are of particular importance inasmuch as these groups are subject to multiple reactivation in water and hence provide increased coating efficiency. The azides constitute a preferred class of photoreactive species and include derivatives based on arylazides (C 6 R 5 N 3 ) such as phenyl azide and particularly 4-fluoro-3-nitrophenyl azide, acyl azides (—CO—N 3 ) such as benzoyl azide and p-methylbenzoyl azide, azido formates (—O—CO—N 3 ) such as ethyl azidoformate, phenyl azidoformate, sulfonyl azides (—SO 2 —N 3 ) such as benzenesulfonyl azide, and phosphoryl azides (RO) 2 PON 3 such as diphenyl phosphoryl azide and diethyl phosphoryl azide. Diazo compounds constitute another class of photoreactive species and include derivatives of diazoalkanes (—CHN 2 ) such as diazomethane and diphenyldiazomethane, diazoketones (—CO—CHN 2 ) such as diazoacetophenone and 1-trifluoromethyl-1-diazo-2-pentanone, diazoacetates (—O—CO—CHN 2 ) such as t-butyl diazoacetate and phenyl diazoacetate, and beta-keto-alpha-diazoacetates (—CO—CN 2 —CO—O—) such as t-butyl alpha diazoacetoacetate. Other photoreactive species include the diazirines (—CHN 2 ) such as 3-trifluoromethyl-3-phenyldiazirine, and ketenes (—CH═C═O) such as ketene and diphenylketene. Upon activation of the photoreactive species, the coating agents are covalently bound to each other and/or to the material surface by covalent bonds through residues of the photoreactive species. Exemplary photoreactive species, and their residues upon activation, are shown as follows. Photoreactive Group Residue Functionality aryl azides amine R—NH—R′ acyl azides amide R—CO—NH—R′ azidoformates carbamate R—O—CO—NH—R′ sulfonyl azides sulfonamide R—SO 2 —NH—R′ phosphoryl azides phosphoramide (RO) 2 PO—NH—R′ diazoalkanes new C—C bond diazoketones new C—C bond and ketone diazoacetates new C—C bond and ester beta-keto-alpha- new C—C bond diazoacetates and beta-ketoester aliphatic azo new C—C bond diazirines new C—C bond ketenes new C—C bond photoactivated new C—C bond and ketones alcohol The coating agents of the present invention can be applied to any surface having carbon-hydrogen bonds, with which the photoreactive species can react to immobilize the coating agents to surfaces. Examples of suitable surfaces are described in more detail below. A composition of the present invention includes about 0 to about 93.9 mole %, preferably from about 30 to about 70 mole %, and most preferably from about 40 to about 60 mole % of a suitable hydrophilic monomer component. Suitable hydrophilic monomers provide an optimal combination of such properties as water solubility, biocompatability, and wettability. Most preferably, the hydrophilic monomer improves or provides the resultant polymeric complex with improved water solubility, though noting that the carboxylic acid-containing monomer may be hydrophilic as well, and can contribute to this effect. Hydrophilic monomers are preferably taken from the group consisting of alkenyl substituted amides. Examples of preferred hydrophilic monomers include acrylamide, N-vinylpyrrolidone, methacrylamide, acrylamido propanesulfonic acid (AMPS). Acrylamide is an example of a particularly preferred hydrophilic monomer. Such monomers are available commercially from a variety of sources, e.g., Sigma-Aldrich, Inc. (St. Louis, Mo.) and Polysciences, Inc. (Warrington, Pa.). The word “medicament”, as used herein, will refer to a wide range of biologically active materials or drugs that can be incorporated into a coating composition of the present invention. The substances to be incorporated preferably do not chemically interact with the composition during fabrication, or during the release process. Additives such as inorganic salts, BSA (bovine serum albumin), and inert organic compounds can be used to alter the profile of substance release, as known to those skilled in the art. The term “medicament”, in turn, will refer to a peptide, protein, carbohydrate, nucleic acid, lipid, polysaccharide or combinations thereof, or synthetic inorganic or organic molecule, that causes a biological effect when administered in vivo to an animal, including but not limited to birds and mammals, including humans. Nonlimiting examples are antigens, enzymes, hormones, receptors, peptides, and gene therapy agents. Examples of suitable gene therapy agents include a) therapeutic nucleic acids, including antisense DNA and antisense RNA, and b) nucleic acids encoding therapeutic gene products, including plasmid DNA and viral fragments, along with associated promoters and excipients. Examples of other molecules that can be incorporated include nucleosides, nucleotides, antisense, vitamins, minerals, and steroids. Coating compositions prepared according to this process can be used to deliver drugs such as nonsteroidal anti-inflammatory compounds, anesthetics, chemotherapeutic agents, immunotoxins, immunosuppressive agents, steroids, antibiotics, antivirals, antifungals, and steroidal antiinflammatories, anticoagulants. For example, hydrophobic drugs such as lidocaine or tetracaine can be included in the coating and are released over several hours. Classes of medicaments which can be incorporated into coatings of this invention include, but are not limited to, anti-AIDS substances, anti-cancer substances, antibiotics, anti-viral substances, enzyme inhibitors, neurotoxins, opioids, hypnotics, antihistamines, immunosuppresents (e.g., cyclosporin), tranquilizers, anti-convulsants, muscle relaxants and anti-Parkinson substances, anti-spasmodics and muscle contractants, miotics and anti-cholinergics, immunosuppressants (e.g. cyclosporine) anti-glaucoma solutes, anti-parasite and/or anti-protozoal solutes, anti-hypertensives, analgesics, anti-pyretics and anti-inflammatory agents (such as NSAID's), local anesthetics, ophthalmics, prostaglandins, anti-depressants, anti-psychotic substances, anti-emetics, imaging agents, specific targeting agents, neurotransmitters, proteins and cell response modifiers. A more complete listing of classes of medicaments may be found in the Pharmazeutische Wirkstoffe, ed. A. Von Kleemann and J. Engel, Georg Thieme Verlag, Stuttgart/New York, 1987, incorporated herein by reference. Antibiotics are art recognized and are substances which inhibit the growth of or kill microorganisms. Antibiotics can be produced synthetically or by microorganisms. Examples of antibiotics include penicillin, tetracycline, chloramphenicol, minocycline, doxycycline, vancomycin, bacitracin, kanamycin, neomycin, gentamycin, erythromycin and cephalosporins. Examples of cephalosporins include cephalothin, cephapirin, cefazolin, cephalexin, cephradine, cefadroxil, cefamandole, cefoxitin, cefaclor, cefuroxime, cefonicid, ceforanide, cefotaxime, moxalactam, ceftizoxime, ceftriaxone, and cefoperazone. Antiseptics are recognized as substances that prevent or arrest the growth or action of microorganisms, generally in a nonspecific fashion, e.g., either by inhibiting their activity or destroying them. Examples of antiseptics include silver sulfadiazine, chlorhexidine, glutaraldehyde, peracetic acid, sodium hypochlorite, phenols, phenolic compounds, iodophor compounds, quaternary ammonium compounds, and chlorine compounds. Anti-viral agents are substances capable of destroying or suppressing the replication of viruses. Examples of anti-viral agents include α-methyl-P-adamantane methylamine), hydroxyethoxymethylguanine, adamantanamine, 5-iodo-2′-deoxyuridine, trifluorothymidine, interferon, and adenine arabinoside. Enzyme inhibitors are substances which inhibit an enzymatic reaction. Examples of enzyme inhibitors include edrophonium chloride, N-methylphysostigmine, neostigmine bromide, physostigmine sulfate, tacrine HCL, tacrine, 1-hydroxy maleate, iodotubercidin, p-bromotetramisole, 10-(a-diethylaminopropionyl)-phenothiazine hydrochloride, calmidazolium chloride, hemicholinium-3,3,5-dinitrocatechol, diacylglycerol kinase inhibitor I, diacylglycerol kinase inhibitor II, 3-phenylpropargylaminie, N-monomethyl-L-arginine acetate, carbidopa, 3-hydroxybenzylhydrazine HCl, hydralazine HCl, clorgyline HCl, deprenyl HCl, L(−), deprenyl HCl, D(+), hydroxylamine HCl, iproniazid phosphate, 6-MeO-tetrahydro-9H-pyrido-indole, nialamide, pargyline HCl, quinacrine HCl, semicarbazide HCl, tranylcypromine HCl, N,N-diethylaminoethyl-2,2-diphenylvalerate hydrochloride, 3-isobutyl-1-methylxanthne, papaverine HCl, indomethacind, 2-cyclooctyl-2-hydroxyethylamine hydrochloride, 2,3-dichloro-a-methylbenzylamine (DCMB), 8,9-dichloro-2,3,4,5-tetrahydro-1H-2-benzazepine hydrochloride, p-aminoglutethimide, p-aminoglutethimide tartrate, R(+), p-aminoglutethimide tartrate, S(−), 3-iodotyrosine, alpha-methyltyrosine, L(−), alpha-methyltyrosine, D L(−), cetazolamide, dichlorphenamide, 6-hydroxy-2-benzothiazolesulfonamide, and allopurinol. Anti-pyretics are substances capable of relieving or reducing fever. Anti-inflammatory agents are substances capable of counteracting or suppressing inflammation. Examples of such agents include aspirin (salicylic acid), indomethacin, sodium indomethacin trihydrate, salicylamide, naproxen, colchicine, fenoprofen, sulindac, diflunisal, diclofenac, indoprofen and sodium salicylamide. Local anesthetics are substances which have an anesthetic effect in a localized region. Examples of such anesthetics include procaine, lidocaine, tetracaine and dibucaine. Imaging agents are agents capable of imaging a desired site, e.g., tumor, in vivo. Examples of imaging agents include substances having a label which is detectable in vivo, e.g., antibodies attached to fluorescent labels. The term antibody includes whole antibodies or fragments thereof. Cell response modifiers are chemotactic factors such as platelet-derived growth factor (pDGF). Other chemotactic factors include neutrophil-activating protein, monocyte chemoattractant protein, macrophage-inflammatory protein, SIS (small inducible secreted), platelet factor, platelet basic protein, melanoma growth stimulating activity, epidermal growth factor, transforming growth factor (alpha), fibroblast growth factor, platelet-derived endothelial cell growth factor, insulin-like growth factor, nerve growth factor and bone growth/cartilage-inducing factor (alpha and beta). Other cell response modifiers are the interleukins, interleukin inhibitors or interleukin receptors, including interleukin 1 through interleukin 10; interferons, including alpha, beta and gamma; hematopoietic factors, including erythropoietin, granulocyte colony stimulating factor, macrophage colony stimulating factor and granulocyte-macrophage colony stimulating factor; tumor necrosis factors, including alpha and beta; transforming growth factors (beta), including beta-1, beta-2, beta-3, inhibin, activin, and DNA that encodes for the production of any of these proteins. The coating composition of the present invention can be used in combination with a variety of devices, including those used on a temporary, transient or permanent basis upon and/or within the body. Examples of medical devices suitable for the present invention include, but are not limited to catheters, implantable vascular access ports, blood storage bags, vascular stents, blood tubing, central venous catheters, arterial catheters, vascular grafts, intraaortic balloon pumps, heart valves, cardiovascular sutures, total artificial hearts and ventricular assist pumps, extracorporeal devices such as blood oxygenators, blood filters, hemodialysis units, hemoperfusion units, plasmapheresis units, hybrid artificial organs such as pancreas or liver and artificial lungs, as well as filters adapted for deployment in a blood vessel in order to trap emboli (also known as “distal protection devices”). Devices which are particularly suitable include vascular stents such as self-expanding stents and balloon expandable stents. Examples of self-expanding stents useful in the present invention are illustrated in U.S. Pat. Nos. 4,655,771 and 4,954,126 issued to Wallsten and 5,061,275 issued to Wallsten et al. Examples of appropriate balloon-expandable stents are shown in U.S. Pat. No. 4,733,665 issued to Palmaz, U.S. Pat. No. 4,800,882 issued to Gianturco and U.S. Pat. No. 4,886,062 issued to Wiktor. Similarly, urinary implants such as drainage catheters are also particularly appropriate for the invention. The surfaces of the medical devices may be formed from polymeric, metallic and/or ceramic materials. Suitable polymeric materials include, without limitation, polyurethane and its copolymers, silicone and its copolymers, ethylene vinyl-acetate, thermoplastic elastomers, polyvinyl chloride, polyolefins, cellulosics, polyamides, polyesters, polysulfones, polytetrafluorethylenes, polycarbonates, acrylonitrile butadiene styrene copolymers, acrylics, polylactic acid, polyglycolic acid, polycaprolactone, polylactic acid-polyethylene oxide copolymers, cellulose, collagens, and chitins. Metallic materials include metals and alloys based on titanium (such as nitinol, nickel titanium alloys, thermo-memory alloy materials), stainless steel, tantalum, nickel-chrome, or cobalt-chromium (such those available under the tradenames Elgiloy™ and Phynox™). Metallic materials also include clad composite filaments, such as those disclosed in WO 94/16646. Examples of ceramic materials include ceramics of alumina and glass-ceramics such as those available under the tradename Macor™. The substrates that can be coated with a composition of the present invention include materials that are substantially insoluble in body fluids and that are generally designed and constructed to be placed in or onto the body or to contact fluid of the body. The substrates preferably have the physical properties such as strength, elasticity, permeability and flexibility required to function for the intended purpose; can be purified, fabricated and sterilized easily; will substantially maintain their physical properties and function during the time that they remain implanted in or in contact with the body. Examples of such substrates include: metals such as titanium/titanium alloys, TiNi (shape memory/super elastic), aluminum oxide, platinum/platinum alloys, stainless steels, MP35N, elgiloy, haynes 25, stellite, pyrolytic carbon, silver or glassy carbon; polymers such as polyurethanes, polycarbonates, silicone elastomers, polyolefins including polyethylenes or polypropylenes, polyvinyl chlorides, polyethers, polyesters, nylons, polyvinyl pyrrolidones, polyacrylates and polymethacrylates such as polymethylmethacrylate (“PMMA”), n-Butyl cyanoacrylate, polyvinyl alcohols, polyisoprenes, rubber, cellulosics, polyvinylidene fluoride (“PVDF”), polytetrafluoroethylene, ethylene tetrafluoroethylene copolymer (“ETFE”), acrylonitrile butadiene ethylene, polyamide, polyimide, styrene acrylonitrile, and the like; minerals or ceramics such as hydroxyapatite; human or animal protein or tissue such as bone, skin, teeth, collagen, laminin, elastin or fibrin; organic materials such as wood, cellulose, or compressed carbon; and other materials such as glass, or the like. Substrates made using these materials can be coated or remain uncoated, and derivatized or remain underivatized. Medical devices upon or into which the composition can be coated include, but are not limited to, surgical implants, prostheses, and any artificial part or device which replaces or augments a part of a living body or comes into contact with bodily fluids, particularly blood. The substrates can be in any shape or form including tubular, sheet, rod and articles of proper shape. Various medical devices and equipment usable in accordance with the invention are known in the art. Examples of devices include catheters, suture material, tubing, and fiber membranes. Examples of catheters include central venous catheters, thoracic drain catheters, angioplasty balloon catheters. Examples of tubing include tubing used in extracorporeal circuitry, such as whole blood oxygenators. Examples of membranes include polycarbonate membranes, haemodialysis membranes, membranes used in diagnostic or biosensor devices. Also included are devices used in diagnosis, as well as polyester yarn suture material such as polyethylene ribbon, and polypropylene hollow fiber membranes. Further illustrations of medical devices include the following: autotransfusion devices, blood filters, blood pumps, blood temperature monitors, bone growth stimulators, breathing circuit connectors, bulldog clamps, cannulae, grafts, implantible pumps, impotence and incontinence implants, intra-ocular lenses, leads, lead adapters, lead connectors, nasal buttons, orbital implants, cardiac insulation pads, cardiac jackets, clips, covers, dialators, dialyzers, disposable temperature probes, domes, drainage products, drapes, ear wicks, electrodes, embolic devices, esophageal stethoscopes, fracture fixation devices, gloves, guide wires, hemofiltration devices, hubs, intra-arterial blood gas sensors, intracardiac suction devices, intrauterine pressure devices, nasal spetal splints, nasal tampons, needles, ophthalmic devices, PAP brushes, periodontal fiber adhesives, pessary, retention cuffs, sheeting, staples, stomach ports, surgical instruments, transducer protectors, ureteral stents, vaginal contraceptives, valves, vessel loops, water and saline bubbles, acetabular cups, annuloplasty ring, aortic/coronary locators, artificial pancreas, batteries, bone cement, breast implants, cardiac materials, such as fabrics, felts, mesh, patches, cement spacers, cochlear implant, defibrillators, generators, orthopedic implants, pacemakers, patellar buttons, penile implant, pledgets, plugs, ports, prosthetic heart valves, sheeting, shunts, umbilical tape, valved conduits, and vascular access devices. Generally, a solution of the copolymer is prepared at a concentration of about 1% to a concentration of about 10% in water or an aqueous buffer solution. Depending on the surface being coated, an organic solvent such as isopropyl alcohol (“IPA”) can be included in the solution at concentrations varying from about 1 to about 40%. The medical device or surface to be coated can be dipped into the copolymer solution, or, alternatively, the copolymer solution can be applied to the surface of the device by spraying or the like. At this point, the device can be air-dried to evaporate the solvent or can proceed to the illumination step without drying. The devices can be rotated and illuminated with UV light for 5-10 minutes to insure an even coat of the coating. This process can be repeated multiple times to attain the desired coating thickness. Coating thicknesses can be evaluated using scanning electron microscopy (SEM) in both the dry and hydrated forms. The difference in thickness between the dry and the hydrated condition is not generally significant. The thickness of the coating ranges from about 0.5 microns to about 20 microns and preferably from about 2 microns to about 10 microns. If a significant amount of surface area is to be coated, it may be preferable to place the device in a rotating fixture to facilitate the coverage of the device's surface. For example, to coat the entire surface of a vascular stent, the ends of the device are fastened to a rotating fixture by resilient retainers, such as alligator clips. The stent is rotated in a substantially horizontal plane around its axis. The spray nozzle of the airbrush is typically placed 2-4 inches from the device. The thickness of the coating can be adjusted by the speed of rotation and the flow rate of the spray nozzle. Medicament is typically incorporated into the matrix after the matrix itself has been coated onto a medical device. Generally a solution of medicament or medicaments is prepared and the matrix-coated device is soaked in the solution. Medicament is absorbed into the matrix from the solution. Various solvents can be used to form the medicament solution as the amount of medicament absorbed by the matrix can be controlled by the solvent solution. Likewise, the pH and/or the ionic strength of the medicament solution can be adjusted to control the degree of medicament absorption by the matrix. After soaking in medicament solution for a period of time, the medical device is removed and air dried. A coating of the present invention is preferably sufficiently durable and tenacious to permit the coating to remain on the device surface, in vivo, for a period of time sufficient for its intended use, including the delivery of medicaments. The durability and/or tenacity of various coatings, on various surfaces, can be assessed using conventional techniques. Applicants, for instance, have constructed a device that includes the use of an adjustable O-ring connected to a high-end torque screw-driver. Using this device it is possible to place a constant and replicable force on a coated medical device, e.g., a catheter. The coated medical device to be tested is inserted into the O-ring and the torque applied to a desired level. The coated device is pulled through the device a predetermined number of times. The coated device is then removed from the O-ring and the device evaluated to determine the amount of matrix remaining on the surface. The matrix remaining on the surface can be detected either directly, e.g., by staining, and/or indirectly, e.g., using a drug loading and release assay. After 5 cycles through the device described above, a medical device coated with a formulation of the present invention, preferably retains the ability to absorb and release at least 75% of its initial capacity. Other suitable biomaterials include those substances that do not possess abstractable hydrogens to which the photogroups can form covalent bonds. Such biomaterials can be used in a variety of ways. For instance, biomaterials can be made suitable for coating via photochemistry by applying a suitable primer coating which bonds to the biomaterial surface and provides a suitable substrate for binding by the photogroups. For instance, metals and ceramics having oxide groups on their surfaces can be made suitable for coupling via photochemistry by adding a primer coating that binds to the oxide groups and provides abstractable hydrogens. Such metals include, but are not limited to, titanium, stainless steel, and cobalt chromium, while such ceramics can include, but are not limited to, silicon nitride, silicon carbide, zirconia, and alumina, as well as glass, silica, and sapphire. One suitable class of primers for metals and ceramics are organosilane reagents, which bond to the oxide surface and provide hydrocarbon groups (Brzoska, J. B., et. al., Langmuir 10:4367-4373, 1994). This reference teaches that —SiH groups are suitable alternatives for bonding of photogroups. Similarly, various tie layers can be applied to various metals, glass, and ceramics, which can in turn serve as sources of abstractable hydrogens for photochemical coupling to the surface. Various polymeric materials such as Nylon, polystyrene, polyurethane, polyethylene terepthalate, and various monomeric analogs used to prepare such polymers could be used for such tie layers. See, for instance, U.S. Pat. Nos. 5,443,455; 5,749,837; 5,769,796; 5,997,517. The present invention further includes the optional use of additional, e.g., “clad”, layers covering and/or between layers of the composition in either a continuous or discontinuous fashion. For instance, one or more outer layers of one or more other materials, e.g., a hydrophilic or protective outer coating, can be photoimmobilized or otherwise bound, absorbed or attached on or to a coating prepared as described herein. If desired, for instance, such an additional coating can be applied on top of a medicament absorbing layer, either before and/or after medicament has been absorbed into the matrix. It is preferable to add the additional layer before medicament has been absorbed. For instance, a solution of the same or of a different copolymer can be prepared and the coated device dipped, sprayed or otherwise contacted with the solution and illuminated as described previously. The coated device can then be contacted with, e.g., soaked in, the medicament solution as described previously. Medicament will pass through the top coat and be absorbed by the underlying matrix. When placed in the body, the medicament will be released as described herein. Using such a method, a coating with enhanced lubricity, hemocompatibility, or other desired property can be incorporated into the medical device surface, thus forming a device coating that provides multiple desired properties. The invention will be further described with reference to the following non-limiting examples. EXAMPLES Example 1 Preparation of 4-Benzoylbenzoyl Chloride (BBA-Cl) (Compound I) 4-Benzoylbenzoic acid (BBA), 1.0 kg (4.42 moles), was added to a dry 5 liter Morton flask equipped with reflux condenser and overhead stirrer, followed by the addition of 645 ml (8.84 moles) of thionyl chloride and 725 ml of toluene. Dimethylformamide, 3.5 ml, was then added and the mixture was heated at reflux for 4 hours. After cooling, the solvents were removed under reduced pressure and the residual thionyl chloride was removed by three evaporations using 3×500 ml of toluene. The product was recrystallized from 1:4 toluene:hexane to give 988 g (91% yield) after drying in a vacuum oven. Product melting point was 92-94° C. Nuclear magnetic resonance (“NMR”) analysis at 80 MHz ( 1 H NMR (CDCl 3 )) was consistent with the desired product: aromatic protons 7.20-8.25 (m, 9H). All chemical shift values are in ppm downfield from a tetramethylsilane internal standard. The final compound (Compound I shown below) was stored for use in the preparation of a monomer used in the synthesis of photoactivatable polymers as described, for instance, in Example 3. Example 2 Preparation of N-(3-Aminopropyl)methacrylamide Hydrochloride (APMA) (Compound II) A solution of 1,3-diaminopropane, 1910 g (25.77 moles), in 1000 ml of CH 2 Cl 2 was added to a 12 liter Morton flask and cooled on an ice bath. A solution of t-butyl phenyl carbonate, 1000 g (5.15 moles), in 250 ml of CH 2 Cl 2 was then added dropwise at a rate which kept the reaction temperature below 15° C. Following the addition, the mixture was warmed to room temperature and stirred 2 hours. The reaction mixture was diluted with 900 ml of CH 2 Cl 2 and 500 g of ice, followed by the slow addition of 2500 ml of 2.2 N NaOH. After testing to insure the solution was basic, the product was transferred to a separatory funnel and the organic layer was removed and set aside as extract #1. The aqueous was then extracted with 3×1250 ml of CH 2 Cl 2 , keeping each extraction as a separate fraction. The four organic extracts were then washed successively with a single 1250 ml portion of 0.6 N NaOH beginning with fraction #1 and proceeding through fraction #4. This wash procedure was repeated a second time with a fresh 1250 ml portion of 0.6 N NaOH. The organic extracts were then combined and dried over Na 2 SO 4 . Filtration and evaporation of solvent to a constant weight gave 825 g of N-mono-t-BOC-1,3-diaminopropane which was used without further purification. A solution of methacrylic anhydride, 806 g (5.23 moles), in 1020 ml of CHCl 3 was placed in a 12 liter Morton flask equipped with overhead stirrer and cooled on an ice bath. Phenothiazine, 60 mg, was added as an inhibitor, followed by the dropwise addition of N-mono-t-BOC-1,3-diaminopropane, 825 g (4.73 moles), in 825 ml of CHCl 3 . The rate of addition was controlled to keep the reaction temperature below 10° C. at all times. After the addition was complete, the ice bath was removed and the mixture was left to stir overnight. The product was diluted with 2400 ml of water and transferred to a separatory funnel. After thorough mixing, the aqueous layer was removed and the organic layer was washed with 2400 ml of 2 N NaOH, insuring that the aqueous layer was basic. The organic layer was then dried over Na 2 SO 4 and filtered to remove drying agent. A portion of the CHCl 3 solvent was removed under reduced pressure until the combined weight of the product and solvent was approximately 3000 g. The desired product was then precipitated by slow addition of 11.0 liters of hexane to the stirred CHCl 3 solution, followed by overnight storage at 4° C. The product was isolated by filtration and the solid was rinsed twice with a solvent combination of 900 ml of hexane and 150 ml of CHCl 3 . Thorough drying of the solid gave 900 g of N-[N′-(t-butyloxycarbonyl)-3-aminopropyl]-methacrylamide, m.p. 85.8° C. by differential scanning calorimetry (“DSC”). Analysis on an NMR spectrometer was consistent with the desired product: 1 H NMR (CDCl 3 ) amide NH's 6.30-6.80, 4.55-5.10 (m, 2H), vinyl protons 5.65, 5.20 (m, 2H), methylenes adjacent to N 2.90-3.45 (m, 4H), methyl 1.95 (m, 3H), remaining methylene 1.50-1.90 (m, 2H), and t-butyl 1.40 (s, 9H). A 3-neck, 2 liter round bottom flask was equipped with an overhead stirrer and gas sparge tube. Methanol, 700 ml, was added to the flask and cooled on an ice bath. While stirring, HCl gas was bubbled into the solvent at a rate of approximately 5 liters/minute for a total of 40 minutes. The molarity of the final HCl/MeOH solution was determined to be 8.5 M by titration with 1 N NaOH using phenolphthalein as an indicator. The N-[N′-(t-butyloxycarbonyl)-3-aminopropyl]methacrylamide, 900 g (3.71 moles), was added to a 5 liter Morton flask equipped with an overhead stirrer and gas outlet adapter, followed by the addition of 1150 ml of methanol solvent. Some solids remained in the flask with this solvent volume. Phenothiazine, 30 mg, was added as an inhibitor, followed by the addition of 655 ml (5.57 moles) of the 8.5 M HCl/MeOH solution. The solids slowly dissolved with the evolution of gas but the reaction was not exothermic. The mixture was stirred overnight at room temperature to insure complete reaction. Any solids were then removed by filtration and an additional 30 mg of phenothiazine were added. The solvent was then stripped under reduced pressure and the resulting solid residue was azeotroped with 3×1000 ml of isopropanol with evaporation under reduced pressure. Finally, the product was dissolved in 2000 ml of refluxing isopropanol and 4000 ml of ethyl acetate were added slowly with stirring. The mixture was allowed to cool slowly and was stored at 4° C. overnight. Compound II was isolated by filtration and was dried to constant weight, giving a yield of 630 g with a melting point of 124.7° C. by DSC. Analysis on an NMR spectrometer was consistent with the desired product: 1 H NMR (D 2 O) vinyl protons 5.60, 5.30 (m, 2H), methylene adjacent to amide N 3.30 (t, 2H), methylene adjacent to amine N 2.95 (t, 2H), methyl 1.90 (m, 3H), and remaining methylene 1.65-2.10 (m, 2H). The final compound (Compound II shown below) was stored for use in the preparation of a monomer used in the synthesis of photoactivatable polymers as described, for instance, in Example 3. Example 3 Preparation of N-[3-(4-Benzoylbenzamido)propyl]methacrylamide (BBA-APMA) (Compound III) Compound II 120 g (0.672 moles), prepared according to the general method described in Example 2, was added to a dry 2 liter, three-neck round bottom flask equipped with an overhead stirrer. Phenothiazine, 23-25 mg, was added as an inhibitor, followed by 800 ml of chloroform. The suspension was cooled below 10° C. on an ice bath and 172.5 g (0.705 moles) of Compound I, prepared according to the general method described in Example 1, were added as a solid. Triethylamine, 207 ml (1.485 moles), in 50 ml of chloroform was then added dropwise over a 1-1.5 hour time period. The ice bath was removed and stirring at ambient temperature was continued for 2.5 hours. The product was then washed with 600 ml of 0.3 N HCl and 2×300 ml of 0.07 N HCl. After drying over sodium sulfate, the chloroform was removed under reduced pressure and the product was recrystallized twice from 4:1 toluene:chloroform using 23-25 mg of phenothiazine in each recrystallization to prevent polymerization. Typical yields of Compound III were 90% with a melting point of 147-151° C. Analysis on an NMR spectrometer was consistent with the desired product: 1 H NMR (CDCl 3 ) aromatic protons 7.20-7.95 (m, 9H), amide NH 6.55 (broad t, 1H), vinyl protons 5.65, 5.25 (m, 2H), methylenes adjacent to amide N's 3.20-3.60 (m, 4H), methyl 1.95 (s, 3H), and remaining methylene 1.50-2.00 (m, 2H). The final compound (Compound III shown below) was stored for use in the synthesis of photoactivatable polymers as described in Examples 4 and 5. Example 4 Preparation of Polyacrylamide(36%)co-Methacrylic acid(MA)-(10%)co-Methoxy PEG1000MA-(4%)co-BBA-APMA (Compound IV) Acrylamide, 39.3 g (0.55 mole), and BBA-APMA (Compound III), 15.5 g (0.04 mole), were dissolved in dimethylsulfoxide (“DMSO”), followed by methoxypolyethyleneglycol 1000 monomethacrylate (methoxy PEG 1000 MA), 110.8 g (0.11 mole), methacrylic acid, 33.8 ml (0.4 mole), 2,2′-azobisisobutyronitrile (“AIBN”), 2.3 g (0.01 mole), and N,N,N′,N′,-tetramethylethylenediamine (“TEMED”), 2.2 ml (0.02 mole). The solution was deoxygenated with a helium sparge for 60 minutes at 60° C., then sealed under argon and heated overnight at 60° C. The resulting product was dialyzed against deionized water using 12,000-14,000 molecular weight cutoff tubing for 66 to 96 hours, then filtered through Whatman #1 filter paper before being lyophilized to give 190 g of polymer. The resultant polymer was identified as methacrylic acid-co-methoxy PEG1000-MA-co-BBA-APMA having the following general structure (Compound IV). Example 5 Preparation of Various Analogs of Compound (IV) A series of polymers of the general formula of Compound IV were synthesized as generally described in Example 4. The mole percent of acrylamide and methoxy PEG1000 monomethacrylate were varied while the mole percent of the BBA-APMA (Compound III) was constant at four mole percent. The ratios of the other groups to carbonyl groups in the various polymers were calculated assuming each mole of the methoxy PEG1000 monomethacrylate contained 23 ether groups. A list of the various polymers prepared and the composition of the various polymers are listed below. The following compounds were synthesized in a manner analogous to that described above with respect to Compound IV. 2. 4% BBA-APMA, 10% methoxy PEG1000 monomethacrylate, 86% Methacrylic acid (Polymer #8 in table below) 3. 4% BBA-APMA, 2% methoxy PEG1000 monomethacrylate, 66% Acrylamide, 28% Methacrylic acid (Polymer #1 in table below) 4. 4% BBA-APMA, 2% methoxy PEG1000 monomethacrylate, 42% Acrylamide, 52% Methacrylic acid (Polymer #2 in table below) 5. 4% BBA-APMA, 26% methoxy PEG1000 monomethacrylate, 42% Acrylamide, 28% Methacrylic acid (Polymer #3 in table below) 6. 4% BBA-APMA, 2% methoxy PEG1000 monomethacrylate, 54% Acrylamide, 40% Methacrylic acid (Polymer #4 in table below) 7. 4% BBA-APMA, 14% methoxy PEG1000 monomethacrylate, 54% Acrylamide, 28% Methacrylic acid (Polymer #5 in table below) 8. 4% BBA-APMA, 14% methoxy PEG1000 monomethacrylate, 42% Acrylamide, 40% Methacrylic acid (Polymer #6 in table below) 9. 4% BBA-APMA, 2% methoxy PEG1000 monomethacrylate, 42% Acrylamide, 52% Methacrylic acid 10. 4% BBA-APMA, 60% Acrylamide, 36% Methacrylic acid 11. 4% BBA-APMA, 50% Acrylamide, 46% Methacrylic acid 12. 4% BBA-APMA, 40% Acrylamide, 56% Methacrylic acid The mole % BBA-APMA was constant at 4 mole %. The ratios of ether groups to carboxyl groups in the various polymers were calculated assuming each mole of methoxy PEG1000 monomethacrylate contained 100/44=23 ether groups. The composition of the various polymers were: Mole % Mole % Mole % Methacrylic Ratio Polymer # Acrylamide MeO-PEG Acid O/COOH 1 66 2 28 1.64 2 42 2 52 0.88 3 42 26 28 21.4** 4 54 2 40 1.15 5 54 14 28 11.5** 6 42 14 40 8.05** 7 50 10 36 6.39 (Compound IV) 8 86 10 0 Undefined **Polymers #3, #5, and #6 were poorly soluble in water and difficult to coat. Example 6 Release of Chlorhexidine Diacetate and Hexachlorophene on Stainless Steel Rods Tested against Staphylococcus epidermidis Stainless steel (SS, 304) rods (0.75 in., 2 cm) were initially pretreated with Parylene C as follows: First, the rods were cleaned with Enprep 160SE detergent (Ethone-OMI Inc., Bridgeview, Ill.) followed by silylation with γ-methacryoxypropyltrimethoxysilane (Sigma Chemical Co., St. Louis, Mo.). Five grams of Parylene C (Specialty Coating Systems, Indianapolis, Ind.) was loaded into the vaporizer of a Labcoter 1, Parylene Deposition Unit, Model PDS 2010 (Specialty Coating Systems, Indianapolis, Ind.) and the parylene was deposited onto the rods in order to achieve a uniform and durable coating of the desired thickness. After precoating, the rods were wiped clean with a cloth soaked in isopropyl alcohol (IPA). A solution of Compound IV was prepared at a concentration of 50 mg/ml in 20% IPA. The rods were dipped at 1.0 cm (0.4 in.)/sec into and 0.5 cm (0.2 in.)/sec out of solution (with no dwell period for the first application and a 30 sec dwell period for the second application). After air-drying for approximately 20 minutes, the coated rods were suspended midway between opposed ELC 4000 lamps (40 cm (15.7 in) apart) containing 400 watt mercury vapor bulbs which put out 1.5 mW/sq. cm from 330-340 nm at the point of illumination. The rods were rotated and illuminated for five minutes to insure an even coat of the coating. Two coats were applied. Two separate solutions of chlorhexidine and hexachlorophene were prepared. Chlorhexidine diacetate (“CDA”) (100 mg/ml) was dissolved in 70% ethanol (EtOH) and hexachlorophene (“HCP”) was also dissolved in 70% EtOH by heating. The SS rods coated with Compound IV were incubated with either the CHA or HCP solution for 30 minutes at room temperature. The parts were air-dried overnight. The longevity of the antiseptic release was evaluated by transferring the rods from one agar surface to a fresh agar surface for zone of inhibition analysis. Basically, the 2 cm (0.8 in.) SS rods were laid parallel on to a Mueller-Hinton agar surface that was incubated with approximately a 1×10 6 CFU/ml of Staphylococcus epidermidis (ATCC 35984). The agar plates containing the parts were incubated overnight at 37° C. The zones of inhibition or areas of no bacterial growth were measured across the diameter of the part. Samples were transferred daily to new agar plates with fresh lawns of S. epidermidis until no zones of inhibition were present. The CDA containing rods produced zones starting at approximately 34 mm and leveling off to 15-18 mm by day 4 and continued at that size through day 14 while the HCP containing parts produced zones starting at approximately 33 mm and leveling off to 30 mm by day 3 and continued at that size through day 14 (end of experiment). Example 7 Release of Chlorhexidine Digluconate (“CHG”) on Stainless Steel Rods Tested against Staphylococcus epidermidis, Staphylococcus aureus, Escherichia coli, and Candida albicans Stainless steel (SS, 304) rods (0.75 in., 2 cm) were pretreated and a solution of compound IV was prepared as described in Example 6. A portion of the rods (0.6 in., 1.6 cm) was dip-coated into the coating solution by dipping into the solution at 0.5 cm (0.2 in.)/sec, swelling for 30 seconds and withdrawing at a rate of 0.2 cm (0.08 in.)/sec for the first 1.2 cm (0.5 in.) of the rod, the reduced to 0.05 cm (0.02 in.) for the last 0.4 cm (0.16 in.) of the rod. The rods were air-dried for 15 minutes and UV illuminated for 5 minutes with rotation as described in Example 6. Two coats were applied. Chlorhexidine digluconate (CHG) (100 mg/ml) was diluted further in deionized (DI) water. Compound IV-coated parylene treated and uncoated rods were sterilized for 20 minutes in 70% IPA and air-dried. All of the rods were soaked for one hour at room temperature in the CHG solution. The parts were then air-dried overnight. The CHG-incorporated parts as well as uncoated and Compound-IV coated without CHG were tested in the zone of inhibition assay agent S. epidermidis (ATCC 35984), S. aureus (ATCC 25923) E. coli (ATCC 25922) and C. albicans (ATCC 10231) as described in Example 6. The following results were obtained. S. epidermidis: The controls for both the uncoated and Compound IV-coated did not produce zones. The uncoated parts with CHG produced zones starting at 22 mm on day 1 and dropped off to no zones by day 4. The parylene-only coated samples with drug gave zones starting at 25 mm and dropped off to zero zones by day 5. The Compound IV-coated samples with CHG incorporated had zones starting at 25 mm, which leveled off to 15-20 mm by day 2 through day 14, and decreasing to 5 mm by day 21. E. coli: The controls with no drug for both uncoated and Compound IV-coated did not produce zones. The uncoated parts with CHG produced zones starting at 15 mm and dropped off with no zones by 4 days. The parylene-only sample with drug gave zones starting at 22 mm and dropped off to no zones by 5 days. The Compound IV-coated samples with drug had zones starting at 20 mm and gradually decreased to no zones by day 21. C. albicans: The controls with no drug for both uncoated and Compound IV-coated produced no zones. The uncoated parts with CHG produced zones starting at 17 mm for day one only. The parylene-only samples with drug gave zones starting at 19 mm and lasted only 2 days. The Compound IV-coated samples with drug gave zones that started at 28 mm and gradually decreased to zero zones by day 18. S. aureus: The controls with no drug for both uncoated and Compound IV-coated did not produce zones. The uncoated parts with CHG produced zones starting at 23 and dropped off to no zones by day 4. The parylene-only samples with drug gave zones starting at 25 mm and dropped off to no zones by day 3. The Compound IV-coated samples with drug had zones starting at 23 mm and gradually decreased to 13 mm through day 12. On day 13 the study was discontinued due to contamination. Example 8 Release of Chlorhexidine Digluconate (CHG) on Titanium Rods Tested against S. epidermidis, S. aureus, E. coli, and C. albicans Titanium (90 Ti/6 Al/4V) rods (0.75 in., 2 cm) were pretreated with parylene and a Compound IV solution was prepared as described in Example 6. The rods were dip coated as described in Example 7, except that the entire rod was coated. The rods were air-dried and UV cured as described in Example 6. Two coats were applied. The uncoated, parylene treated, and Compound IV-coated rods were sterilized in 70% IPA for 20 minutes and air-dried. The samples were then incorporated with CHG at 100 mg/ml in DI water for one hour at room temperature with agitation. The rods were rinsed by dipping three times into tubes containing DI water and air-dried overnight. The quantity of CHG eluted from the rods was also determined. The individual rods were placed into test tubes containing 2 ml of Phosphate Buffer Saline (“PBS”) and were incubated at 37° C. overnight with agitation. The rods were transferred to fresh PBS daily, and the eluates were diluted into the High Pressure Liquid Chromatography (HPLC) mobile phase to solubilize the CHG. The amount of CHG eluted was measured by HPLC and was determined to be 12.3 μg/rod for uncoated, 10.1 μg/rod for parylene-only, and 275 μg/rod for Compound IV-coated. Also the CHG incorporated parts, as well as uncoated and Compound IV-coated without CHG were tested in the zone of inhibition assay against S. epidermidis (ATCC 35984), S. aureus (ATCC 25923) E. coli (ATCC 25922) and C. albicans (ATCC 10231) as described in Example 6. The results were as follows: S. epidermidis: The uncoated and parylene-only gave zone of 15-18 mm on day 1 and died off by day 3. The Compound IV-coated rods with drug gave zones starting at 24 mm, leveling at 15-19 mm from day 2-21 and then gradually decreasing to no zone on day 27. S. aureus: The uncoated and parylene-only gave zone of 14-16 mm on day 1 and dropped off to no zones by day 3. The Compound IV samples with drug gave zones starting at 20 mm and gradually decreasing to 12 mm on day 16. They were discontinued on day 20 due to contamination. E. coli: Uncoated and parylene-only gave zones of 13-14 mm on day 1 and dropped off to no zones by day 3. The Compound IV sample with drug gave zones starting at 20 mm and gradually decreased to no zones on day 20. C. albicans: Uncoated and parylene-only gave zone of 7-10 mm on day 1 and dropped off to no zone by day 2. The Compound IV samples with drug had zones starting at 19 mm and gradually decreased to no zones on day 21. Example 9 Release of Benzalkonuim Chloride (“BAK”) and CHG from Pebax™ Rods Tested against S. epidermidis and E. coli Pebax™ rods (0.75 in., 2 cm) were wiped clean with an IPA soaked cloth and a Compound IV solution was prepared as described in Example 6. The rods were dipped at 3.0 cm (1.2 in.)/sec into, 30 sec dwell, and a 3.0 cm (1.2 in.)/sec out of solution. The rods were air-dried for approximately ten minutes and UV illuminated for 3 minutes with rotation as described in Example 6. Two coats were applied and a portion of the Pebax™ rods were cut into 1 cm (0.4 in.) pieces for the zone of inhibition testing. BAK and CHG were prepared at 100 mg/ml in DI water and the samples were incorporated for one hour at room temperature with agitation. The rods were rinsed three times in DI water and air-dried overnight. The samples were tested in the zone of inhibition assay against S. epidermidis (ATCC 35984) and E. coli (ATCC 25922) as described in Example 6 except the rods were placed perpendicular into the agar. S. epidermidis results: The Compound IV coatings containing BAK gave zones starting at 26 mm and gradually decreasing to no zones by day 16. The CHG coated rods gave zones that started at 22 mm and gradually decreased to 12 mm on day 16 when the study was discontinued. E. coli: The BAK coated rods gave zones that started at 11 mm but lasted only 2 days. The CHG coated rods gave zones that started at 15 mm and gradually decreased to 9 mm on day 16 when the study was discontinued. Example 10 Release of CHG form Polyurethane (Pellethane) Catheter Material Tested against S. epidermidis The polyurethane (PU) catheter material was wiped clean with IPA and a solution of Compound IV for coating was prepared as described in Example 6. The rods were dip coated in the coating solution by dipping into the solution at 1.0 cm (0.4 in.)/sec, dwelling for 30 seconds, and withdrawing at a rate of 0.5 cm (0.2 in.)/sec. The rods were air-dried for 15 minutes and UV illuminated for three minutes with rotation as described in Example 6. Two coats of the Compound IV coating were applied. The Compound IV coated rods were wiped with 70% IPA and dried for one hour. The rods were cut into 2 cm lengths and the CHG was incorporated by dipping the rods into a 200 mg/ml solution of CHG for one hour at room temperature and then rinsed three times in DI water. The samples were air-dried overnight and tested in the zone of inhibition assay against S. epidermidis (ATCC25984) as described in Example 6. All of the uncoated samples and coated samples containing no drug produced no zones of inhibition. The Compound IV-coated zones with drug started at 28 mm at day zero and gradually decreased to no zones on day 23. Example 11 Release of Alexidine Dihydrochloride (“ADC”) from Polyurethane Rods Tested against S. epidermidis Polyurethane rods (6 in., 15 cm) were wiped clean as described in Example 9 and a Compound IV solution was prepared as in Example 6. The rods were dip-coated by dipping into the solution at a rate of 2.0 cm (0.8 in.)/sec, dwelling for 30 seconds and withdrawing at 3.0 (1.2 in.)/sec. The samples were air-dried for 10 minutes and UV illuminated for two minutes with rotation as described in Example 6. Two coats were applied. A solution of alexidine dihydrochloride (ADC) (100 mg/ml) in 50% methanol was prepared with heat. The PU rods were cut into 1 cm lengths and incorporated with the alexidine in the ADC solution in a warm water bath. The rods were incorporated for one hour, rinsed three times in DI water, and air-dried over night. The samples were tested in the zone of inhibition against S. epidermidis (ATCC 35984) as described in Example 6. All of the uncoated samples and coated samples containing no drug produced no zones of inhibition. The Compound IV-coated zones with alexidine started at 12 mm and leveled off at 6-9 mm form day 2 through the duration of the test period of 21 days. Example 12 Release of Vancomycin (“VA”) on Coated PU Rods Tested against S. epidermidis Polyurethane rods (6 in., 15 cm) were wiped clean as described in Example 9 and a Compound IV solution was prepared as in Example 6. The rods were dip coated in the coating solution by dipping into the solution at 2.0 cm (0.8 in.)/sec, dwelling for 30 seconds, and withdrawing at 2.0 (0.8 in.)/sec. The rods were air-dried for 15 minutes and UV illuminated for four minutes with rotation as described in Example 6. Two coats were applied. A solution of vancomycin (VA) was prepared at 50 mg/ml in DI water. The rods were incorporated with VA in the VA solution for one hour at room temperature, rinsed three times in DI water, air-dried, and cut into 1 cm pieces. The samples were tested against S. epidermidis (ATCC35984) as described in Example 6. All of the uncoated samples and coated samples containing no drug produced no zones of inhibition. The Compound IV coated zones with VA started at 20 mm and dropped off to no zones by day 6.

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CROSS REFERENCE TO RELATED APPLICATION This application is a division of application Ser. No. 226,598, filed Nov. 28, 1988, now U.S. Pat. No. 4,855,375, application which is a continuation-in-part of our copending application, serial number 87,921, filed Aug. 21, 1987, now abandoned all of which is incorporated by reference. BACKGROUND OF THE INVENTION The subject matter of this application is directed toward resins used in the manufacture of reinforced plastics. More particularly, the resins (binders) are used in the preparation of composites formed from fibers embedded in a polymer resin matrix. Even more specifically this application is directed toward the use of such resins in the preparation of circuit board laminates where the reinforcing material is glass or quartz fiber. To overcome some mechanical and structural limitations of plastics it has become relatively commonplace to reinforce them with other components. Composites formed of various fibers embedded in a polymer resin matrix are especially useful and susceptible to enormous variation depending upon the nature of the fiber used, how the fiber is utilized, and the matrix or binder for the fibers. Materials which have been used as fibers include glass, quartz, oriented polymers such as the aramids (Kevlar™), graphite and boron. Whatever their composition such fibers can be used as chopped or continuous filaments, and when used as continuous filaments they can all be unidirectional or woven into a fabric. The matrix can be, for example, a polyester, epoxy, polyimide, polyetherketone or polyetherimide resin as either a thermoset or thermoplastic material. The uses for such composites range from airframes to tennis rackets and from boat hulls to rocket motor casings. A particular area of composite application is that of printed circuit boards, especially multilayer circuit boards, for mounting electronic components. The use of glass fabric as the reinforcing material has become more-or-less standard and epoxy resins are most often used as the matrix. For the fiber to exert a reinforcing action it is necessary that the fibers be completely coated with resin, and to achieve this the glass fiber often is surface treated to provide sites for chemical bonding to the resin or to its precursor or for otherwise improved adhesion to the matrix material. Multilayer circuit boards are laminates with alternating layers of composite and etched copper sheet. A brief discussion of their manufacture will aid in appreciating the properties requisite for such boards. A woven glass fabric is first impregnated with resin by dipping the cloth in a resin solution, often referred to as the varnish solution, in what is called the A-stage. Solvent is then removed to afford a glass cloth reinforced resin, or prepreg, in what is called the B-stage. In some cases the resin in the prepreg may be partially cured, in other cases uncured, but in all cases the prepreg is a non-tacky, readily handled rigid sheet of glass cloth embedded in and coated with a resin. The finished circuit board is prepared by laminting alternating layers of prepreg and etched copper foil under conditions of temperature and pressure where resin is cured, i.e., further polymerized and cross-linked to a final infusible, insoluble stage (C-stage). From the above brief description some necessary and desirable characteristics of the resin may be readily discerned. The circuit board will be subjected to soldering temperatures and may be operated at an elevated temperature, or experience cyclic locally elevated temperatures because of local power generation, and thus the thermal coefficient of expansion of the resin should approximate that of glass to ensure continued dimensional stability and resistance to heat distortion. The resin should have a high solubility in the varnish solution to ensure high resin loading. The varnish solution should have a sufficiently low viscosity for even coating but not too low a viscosity as to run off the fibers. It is necessary that the prepreg not be tacky so that it can be readily handled and stored. The resin is desirably noncrystalline for enhanced solubility in the varnish solution and for good film forming properties in the prepreg. The resin should have adequate flow at the C-stage so as to make void-free laminated bonds, with the curing temperature somewhat higher than the glass transition temperature (T g ) of the resin to afford a wider processing "window." The resin also should be chemically resistant to a corrosive environment and to water vapor. To ensure that the discrete electrical components on a circuit board interact only via the etched path on the copper foil, it is desirable that the matrix have a low dielectric constant and high resistance. The invention to be described is an amorphous, thermosetting resin which affords a varnish solution of high solids content with a viscosity leading to even coating without runoff, which affords a non-tacky prepreg, has a glass transition temperature sufficiently below the curing temperature to afford an adequate window of processing, and which shows excellent flow properties at the C-stage. The final cured resin exhibits a low dielectric constant and dissipation factor, a low coefficient of thermal expansion, and a high glass transition temperature. In short, we believe our cured resin has properties superior to those currently recognized as industry standards in the lamination of circuit boards, and thus presents outstanding benefits. U.S. Pat. No. 4,116,936 describes thermosetting resins which are vinylbenzyl ethers of monomeric phenols, of simple phenol-formaldehyde condensation products commonly known as novolac resins, and of oligomers resulting from the reaction of a dihydric phenol, such as bisphenol A, and a glycidyl ether. However much these resins may represent an advance over prior art resins, presumably because the fully cured product shows, among other desirable properties, greater hydrolytic stability and corrosion resistance, we have discovered resins whose properties are decidedly superior in several operational aspects. In particular, whereas the resins of our invention show desirable flow at prepreg temperatures, they exhibit higher flow viscosity in solution at ambient temperature, thereby minimizing runoff and leading to improved coating uniformity. Additionally, the fully cured products of our resins show an improved coefficient of thermal expansion, a particularly important property in laminate production. Thermal expansion is a poorly understood function of the nature of the polymer backbone as well as the nature of the end capping group. The coefficient of thermal expansion can not be predicted, and obtaining thermosetting resins whose thermoset product has a coefficient of thermal expansion similar to that of, e.g., woven glass fabric remains a hit-or-miss affair. For our purposes an ideal fully cured product will have a coefficient of thermal expansion of about 30 ppm. The materials of our invention approach the goal closely. The thermosetting resins of this invention do not appear to have a close analogue in the prior art, with the most relevant art of Wang et al., U.S. Pat. No. 4,707,558, only distantly related. The formulae of the patentees encompass a very large universe of permutations, and in the case where in their formula II m'=0 and m=1 one has a structure which is arguably, and only weakly arguably, pertinent to the materials of this invention. But even within such restrictions one requires a judicious choice of other of the patentees' variables, especially A and X, to arrive at materials even then only remotely related to our invention. It needs to be emphasized that although this application will stress the utilization of the resins of our invention in the production of multilayer circuit boards, the resins may be useful in fabricating composites generally. Consequently, it needs to be explicitly recognized that the resins of our invention are intended for composite manufacture without any limitations other than those imposed by the product specifications themselves. SUMMARY OF THE INVENTION The purpose of our invention is to provide themosetting resins whose properties make them desirable in the preparation of composites, especially in laminated multilayer boards of a glass fiber in a polymer matrix. An embodiment comprises the vinylbenzyl ethers of the oligomeric condensation product of certain dihydric phenols and formaldehyde. In a more specific embodiment the dihydric phenol is what is commonly known as bisphenol-A. In a more specific embodiment the vinylbenzyl ether is a mixture of meta-and para-substituted vinylbenzyl ether. In a still more specific embodiment the aromatic rings are substituted with a methyl group. In still another embodiment from about 50 to 100% of the ether moieties are vinylbenzyl ether moieties, with the remainder being primary alkyl moieties containing from 1 to about 4 carbon atoms. Other embodiments will become apparent from the following description. DESCRIPTION OF THE INVENTION Our invention is a class of thermosetting resins of vinylbenzyl ethers of the oligomeric condensation products of a dihydric phenol and formaldehyde where from 50 to 100% of the ether groups are vinylbenzyl moieties and the remainder, if any, are alkyl moieties containing 1 to 10 carbon atoms or the benzyl moiety. Especially where all the ether moieties are the vinylbenzyl group, the extensively cross-linked polymers resulting from curing the thermosetting resins of this invention have improved properties with regard to their use in printed circuit boards. In particular, they have a dielectric constant which is better than conventional materials, a coefficient of thermal expansion which is better than conventional materials, show excellent solvent resistance (low water pickup), exhibit an improved glass transition temperature, and have a higher flow viscosity in solution at room temperature relative to conventional materials. Our thermosetting resins may be depicted by the formula, ##STR1## The resins of this invention result from the etherification of oligomers which are the condensation product of a dihydric phenol and formaldehyde. Therefore the product will be a mixture of materials with varying molecular weight, that is, the resulting resins are mixtures having discrete components of differing degrees of oligomerization. What needs to be emphasized is that the resins are a mixture of oligomers, and the number, n, of recurring units Q generally will vary from 0 to 10. That is, n is 0 or an integer from 1 to 10, where in the preferred practice of our invention it is 0 or an integer from 1 to 6. As previously mentioned, a spectrum of oligomers typically result from the condensation reaction, and in a desirable branch of our invention the number average of n is about 3, i.e., from 0 to about 5. The recurring unit Q itself has the structure, ##STR2## Note that the condensation may occur either on the same ring, as in the right hand structure, or in different rings, as in the left hand structure. The aromatic rings in the recurring unit Q are either joined directly or are separated by an intervening atom furnished by the moiety X. Therefore, s is 0 or 1. Each of the moieties X may be either a methylene [CH 2 ], isopropylidene [C(CH 3 ) 2 ], hexafluoroisopropylidene [C(CF 3 ) 2 ], an oxygen, sulfur, sulfonyl [S(O) 2 ], carbonyl [C(O)], or a dioxyphenylene group [OC 6 H 4 O], where the oxygens of the latter generally are para or meta to each other. In a favored embodiment X is isopropylidene. Each of the aromatic rings may bear substituents or may be completely unsubstituted. Thus, R 1 and R 2 are independently selected from moieties such as hydrogen, alkyl moieties containing from 1 to 10 carbon atoms, the phenyl moiety, alkoxy moieties containing from 1 to 10 carbon atoms, and phenoxy, C 6 H 5 O. Examples of suitable alkyl moieties include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl moieties. The methyl and tert-butyl groups are preferred alkyl moieties in the practice of our invention, although the variant where R 1 =R 2 =H is quite desirable. The basic resins also can be readily modified to be flame retardant by incorporating halogen atoms into the aromatic rings. Thus, Z may be a halogen atom, especially bromine, and where the aromatic ring is halogenated a and b is an integer from 1 to 4. Polyhalogenated materials are desired as flame retardants, which means that a and b are recommended to be 2, 3, or 4. Where the aromatic rings are not halogen substituted then both a and b are 0. The oligomeric condensation products have a multiplicity of phenolic hydroxyl groups substantially all of which are end-capped as ether groups in our thermosetting resins. The best case results where the ether portion, E, is a vinylbenzyl moiety, that is, of the structure. ##STR3## which may be either the meta-or para-isomer, and which usually is a mixture of the meta-and para-isomers. However desirable it may be to have all the phenolic hydroxyls end-capped with vinylbenzyl moieties, there is a decided cost advantage when fewer than all of the ether groups are vinylbenzyl, usually at the expense of a somewhat lower dielectric constant. In our invention it is required that at least 50% of the E moieties be a vinylbenzyl moiety, but a product with better performance characteristics results when from 70 to 100% of the ether groups are vinylbenzyl, and the best product results when 95 to 100% of such groups are vinylbenzyl. In those cases where less than all of the ether groups are vinylbenzyl, then we are partial to resins where E is an alkyl group containing from 1 to 10 carbons or a benzyl group. Where E is an alkyl group, the primary alkyl groups are given priority, especially the primary lower alkyl groups containing from 1 to 4 carbon atoms. Thus, the most desirable alkyl groups consist of methyl, ethyl, 1-propyl, 1-butyl, and 2-methyl-1-propyl. Other alkyl groups are represented by 1-pentyl, 1-hexyl, 1-heptyl, 1-octyl, 1-nonyl, 1-decyl, 2-methyl-1-butyl, 3-methyl-1-butyl, 2,3-dimethyl-1-butyl, 3,3-dimethyl-1-butyl, 2-methyl-1-pentyl, and so forth. However, it is to be emphasized that a benzyl group also operates quite satisfactorily in the practice of our invention. The resins of our invention may be prepared by acid catalyzed condensation of dihydric phenols with formaldehyde followed by end-capping substantially all the phenolic hydroxyls by converting them to ethers. Acid catalyzed condensation is preferred to avoid the formation of terminal hydroxy methylene groups, --CH 2 OH. End-capping by ether formation can be effected by any suitable means, such as by reacting the phenolic condensation product with an alkyl or benzyl halide in a basic medium. The resulting thermosetting resins are readily polymerized with attendance cross-linking by a variety of curing means. In a preferred mode, curing is effected by thermal means, generally autoinitated by heating the resin in the air at a temperature between about 100° and 250° C., and more particularly between about 120° and 200° C. In practice multilayer boards may be laminated at a temperature between about 150° and about 200° C. for 0.5-5 hours with postcuring at about 180°-250° C. for about 0.5-24 hours. Curing also may be brought about by chemical means using a free radical initiator such as azo-bis-isobutyronitrile, benzoyl peroxide, di-t-butyl peroxide, etc. Curing may be effected as well by irradiation, especially by visible and ultraviolet light in the presence of a suitable photoinitiator. Whether thermal, chemical, or photochemical curing is performed, the resin becomes extensively cross-linked and sets to an infusible, insoluble glassy solid. The materials of our invention also can be blended with other types of vinylbenzyl ethers of functionality greater than or equal to 2 to provide A-stage varnish solutions with tailorable viscosity and variable properties in the cured product such as glass transition temperature, heat distortion temperature, fracture toughness, etc. For example, our resins could be blended with various styrenated bisphenols to raise cross-link density and improve processability of the bis-styryl compound. The materials of our invention are polymers of moderate functionality (i.e., number of vinylbenzyl groups per molecule) and viscosity and they can be incorporated to reduce crystallinity of various styrenated bisphenols where the bisphenols are exemplified by the formula ##STR4## with W being --O--, --C(CH 3 ) 2 --, --SO 2 --, --CO--, and so forth to raise the resin solids content in the A-stage varnish solution, to raise the resin content in the B-stage, and to reduce the amount of resin flow in the C-stage. High-to-moderate molecular weight poly(vinylbenzyl ethers) also may be useful for improving the shelf life of other styrenated oligomers, and may raise the ductility of the otherwise brittle laminate, such as in the case of styrenated bisphenol A. The following examples are merely illustrative of our invention and are not limiting in any way. EXAMPLE 1 Preparation of Styrene Terminated Bisphenol-A-Formaldehyde (STBPA-F). Bisphenol-A-formaldehyde resin was prepared as follows. 150.0 g (0.658 moles) of bisphenol-A was dissolved in 500 ml of ethanol in a 1 liter round bottom flask equipped with condenser and magnetic stirrer. To this reaction mixture was added 0.5 ml of concentrated sulfuric acid. The solution was heated to reflux and then 14.5 g (0.151 moles) of paraformaldehyde was added gradually to the reaction. The reaction was heated at reflux with stirring for 48 hours and then allowed to cool to room temperature. The reaction was neutralized with aqueous sodium hydroxide solution and then concentrated under vacuum, yielding 130.3 g of viscous syrup, with a M w =362. 50.0 g (0.1062 moles) of bisphenol-A formaldehyde resin and 71.35 g (0.4675 moles) of vinylbenzyl chloride (60/40 meta/para isomer ratio) were dissolved in 110 ml of acetone in a three neck-round bottom flask equipped with condenser, addition funnel, thermometer, mechanical stirrer and nitrogen purge. The reaction mixture was heated at reflux (65°-70° C. temperature) for a period of one hour, following which a solution of 41.83 g (0.746 moles) of potassium hydroxide in 93 ml of methanol was added to the warm reaction mixture over an interval of one hour. The reaction was stirred thereafter at ambient temperature for a period of 24 hours. The reaction mixture was recovered, dried over magnesium sulfate, filtered, and concentrated under vacuum. The resulting oil was dried in a vacuum oven at ambient temperature overnight and yielded 24.5 g of resin. EXAMPLE 2 Preparation of Cured STBPA-F. 3.3 g of STBPA-F of Example 1 was placed in a flat casting dish and cured by heating in an oven at a temperature of 120° C. for a period of 2 hours, followed by a 16 hour cure at 160° C. and a 2 hour cure at 200° C. Following this, the sample was then post-cured for a period of 2 hours at 225° C. and recovered. The cured polymer was found to have a glass transition temperature (Tg) of greater than 300° C., a minor softening point (Tsp) (measured via Thermal Mechanical Analysis (TMA)) at 165±5° C., a coefficient of thermal expansion from 25° to 165° C. of 40±2 ppm/°C. and from 25° to 260° C. of 65±3 ppm/°C. The dielectric constant at 1 MHz and dissipation factor at 0% and 50% relative humidity are summarized in the following table. TABLE 1______________________________________Relative Dielectric DissipationHumidity Constant Factor______________________________________ 0% 2.94 ± 0.27 0.004 ± 0.00150% 3.25 ± 0.17 0.013 ± 0.001______________________________________ EXAMPLE 3 Preparation of Cured STBPA-F from Chloroform Solution. 2.0 g of STBPA-F resin of Example 1 was dissolved in about 10 milliliters of chloroform. The resulting solution was transferred to a flat casting dish and heated on a hot plate to remove a major portion of the chloroform solvent. The sample was then cured in an oven at 120° C. for 2 hours, followed by 16 hours at 160° C. and 2 hours at 200° C. The sample was post cured at 225° C. for 1 hour. The cured polymer was found to have the following properties: glass transition temperature (Tg)>300° C., coefficient of thermal expansion from 25 to 260° C. (α 260 ) of 59±4 ppm/°C. and a dielectric constant and dissipation factor (1 MHz) at 0% relative humidity of 2.63±0.17 and 0.007±0.001, respectively. EXAMPLE 4 Preparation of Styrene Terminated Polybrominated Bisphenol-A Formaldehyde (STBBPA-F). 40.57 (0.086 moles) of bisphenol-A formaldehyde resin, 40 milliliters of carbon tetrachloride, 84 milliliters of methanol and 1.99 g of potassium bromide were charged into 500 ml three neck-round bottom flask equipped with condenser, addition funnel, nitrogen purge and magnetic stirring bar. The reaction vessel was placed in a water bath and heated to a temperature of about 50° C. To this 2-phase reaction mixture was added 41.25 milliliters (0.800 moles) of bromine dropwise over a 4 hour period. At the end of this time 80 milliliters of water was added to the reaction mixture and a distillation head attached to the reaction vessel, and the volatile products were distilled off at atmospheric pressure. The remaining residue was taken up in 160 milliliters of dichloromethane and the organic phase was washed three times with 80 milliliters of water and then twice with 80 milliliters of 10% aqueous sodium bisulfite to remove any residual bromine which may be present. The organic phase was washed with 80 milliliters of water and dried over sodium sulfate. The methylene chloride was removed under vacuum and then azeotropic drying with ethanol gave 80.70 grams of product. 40.0 g (0.425 moles) of the above polybrominated bisphenol-A formaldehyde resin and 28.54 g (0.187 moles) of vinylbenzyl chloride (60/40 meta/para isomer ratio) were dissolved in 90 ml of acetone in a three neck-round bottom flask equipped with condenser, addition funnel, thermometers, mechanical stirrer and nitrogen purge. The reaction mixture was heated to reflux (65°-70° C. temperature) for a period of one hour, following which a solution of 12.54 g (0.224 moles) of potassium hydroxide in 28 milliliters of methanol was added to the warm reaction mixture over a period of one hour. Thereafter the reaction was stirred at ambient temperature for a period of 24 hours. The reaction mixture was recovered, dried over magnesium sulfate, filtered and concentrated under vacuum. The resulting oil was dried in a vacuum oven at ambient temperature overnight and yielded 30.8 g of resin. EXAMPLE 5 Preparation of Cured STBBPA-F. 5.0 g of STBBPA-F resin of Example 4 was placed in a flat casting dish and cured by heating in an oven at a temperature of 120° C. for 2 hours, followed by a 16 hour cure at 160° C. and a 2 hour cure at 200° C. The sample was post-cured for a period of 2 hours at 225° C. and recovered. The cured polymer was found to have the followed properties: glass transition temperature (Tg)>250° C., and dielectric constant (1 MHz) and dissipation factor at 0 and 50% relative humidity as tabulated in Table 2. TABLE 2______________________________________Relative Dielectric DissipationHumidity Constant Factor______________________________________ 0% 3.01 ± 0.16 0.002 ± 0.00150% 2.98 ± 0.02 0.009 ± 0.001______________________________________ EXAMPLE 6 Preparation of Cured STBBPA-F from Chloroform Solution. 2.0 g of STBBPA-F resin of Example 4 was dissolved in 10 milliliters of chloroform. The resulting solution was transferred to a flat casting dish and heated on a hot plate to remove the majority of the solvent, the sample was then cured in an oven at 120° C. for 2 hours, followed by 16 hours at 160° C. and 2 hours at 200° C. The sample was post-cured at 225° C. for 1 hour. The cured polymer was found to have the following properties: glass transition temperature (Tg)>250° C., and dielectric constant and dissipation factor at 0% and 50% relative humidity as tabulated in Table 3. TABLE 3______________________________________Relative Dielectric DissipationHumidity Constant Factor______________________________________ 0 2.82 ± 0.16 0.004 ± 0.00250 2.77 ± 0.008 0.012 ± 0.001______________________________________ EXAMPLE 7 Preparation of Cured STBPA; Comparison of Selected Properties. Styrene terminated bisphenol-A was prepared according to the method of Steiner (U.S. Pat. No. 4,116,936) by reacting vinylbenzyl chloride with bisphenol-A. This resin was cured by taking 2.0 g of STBPA and was dissolved in about 10 milliliters of chloroform in a flat casting dish and heated on a hot plate to remove the majority of the solvent. The sample was then cured in an oven at 120° C. for 2 hours, followed by 16 hours at 160° C. and 2 hours at 200° C. The sample was postcured for 1.5 hours at 225° C. The cured polymer had the following properties: glass transition temperature (Tg)>250° C., minor softening point (Tsp) (measured via TMA) at 168±11° C., a coefficient of thermal expansion from 25° to 168° C. of 57±8 ppm/°C. and from 25° to 260° C. of 71±23 ppm/° C. The dielectric constant at 1 MHz and dissipation factor at 0% and 50% relative humidity are summarized in the following table. TABLE 4______________________________________Relative Dielectric DissipationHumidity Constant Factor______________________________________ 0 2.93 ± 0.11 0.003 ± 0.00250 3.15 ± 0.14 0.013 ± 0.001______________________________________

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a scanning tunneling microscope which can be used to observe the surface of a sample in the unit of atom size. 2. Description of the Related Art Recently, a scanning tunneling microscope (STM) which can be used to observe the surface of a sample in the unit of atom size has been developed. It is generally well known in the art that when a metal probe having a sharp tip end is set as close as approx. 1 nm to the surface of an electrically conductive sample and a preset voltage is applied between the probe and the sample, a tunnel current flows between the probe and the sample. The tunnel current is largely dependent on a distance between the probe and the sample. The STM utilizes the property of the tunnel current to observe the surface of the sample. That is, when the probe is mounted on the actuator which can be moved in a 3-dimensional direction and it is scanned while the tunnel current is kept constant, the probe will move along the irregularity of the surface of the sample with a preset distance kept therebetween. Thus, variation of the surface state of the sample can be observed in the unit of atom size as an image by outputting the position of the probe as a 3-dimensional image. In general, a servo circuit is used to adjust the distance between the probe and the sample in the STM. The servo circuit detects a tunnel current flowing between the probe and the sample and controls the driving operation of the actuator to keep the distance between the probe and the sample at a constant value based on the detected tunnel current. In the conventional STM, adjustment of the distance between the probe and the sample is controlled only by use of the above servo circuit. Therefore, when the surface condition of the probe is bad, desired control cannot be effected. That is, when the sample has a slanted surface, undulated surface or a surface having holes formed therein and if the servo output is displayed on a CRT as an output indicating the surface condition of the sample based on the detected tunnel current, the CRT image plane cannot be effectively used and the STM image cannot be displayed within the image plane. In this case, the distance between the probe and the sample cannot be controlled by the servo system so that the STM image obtained can be displayed only with a low resolution in a vertical direction and the dynamic range thereof may be deviated from the central position. Further, as described before, the STM is a microscope having a super high resolution and can be used to observe the surface configuration and surface properties of the sample in the unit of atom size. Therefore, in a case where a desired portion of the sample is observed, it is necessary to first observe a wide range (several μm) previously set to include the desired portion and then observe the desired portion. Further, when an STM image (3-dimensional image) of the wide scanning range is observed, it is sometimes required to enlarge part of the image for more specific observation. In order to meet the above requirements, in the prior art, an image obtained by wide range scanning with a preset resolution is displayed, then the scanning range is changed to a narrow scanning range and the probe is upwardly moved away from the sample surface by such a distance that the tunnel current cannot flow. Then, the scanning center is set on the position at which a portion to be enlarged lies by an X-Y rough moving mechanism using a pulse motor and the like and the lifted probe is set closer to the sample surface so as to be set within a tunnel current region, and then the scanning operation is effected again to display an image. However, in the above method, the precision of the rough moving mechanism for moving the sample influences the reliability of the STM image. Actually, the precision of the rough moving mechanism is extremely lower than the resolution of the STM. According to the method in which the probe is separated from the sample after the wide range scanning operation is effected, and then moved by use of the rough moving mechanism and set closer to the sample again to display an STM image, the desired position cannot always be correctly set because of the low resolution and precision of the rough moving mechanism. Therefore, an enlarged image at exactly the desired position cannot always be obtained. SUMMARY OF THE INVENTION Accordingly, a first object of this invention is to provide a scanning type tunnel microscope in which a servo system for controlling the distance between the probe and the sample can always be set in a proper condition irrespective of the surface condition of the sample. A second object of this invention is to provide a scanning type tunnel microscope capable of setting the starting position of the scanning operation for a desired scanning range to a desired position after the wide range scanning operation is effected without using a rough moving mechanism necessary for movement of the probe in a vertical direction so as to always correctly set the desired position and maintain the reliability of an enlarged image. In order to attain the first object, a scanning tunneling microscope of this invention comprises: a piezoelectric driver capable of expanding and contracting to adjust a distance between a probe and a sample according to a voltage applied thereto, the distance including a distance at which a tunnel current can flow between the probe and the sample; a servo circuit for outputting a servo voltage for controlling expansion and contraction of the piezoelectric driver to keep the tunnel current at a constant value; correction voltage generating means for generating a given correction voltage to correct a voltage to be supplied to the piezoelectric driver; adding means for adding the servo voltage output from the servo circuit and the correction voltage supplied from the correction voltage generating means to each other to supply an added output to the piezoelectric driver; and control means for controlling the correction voltage supplied from the correction voltage generating means based on the servo voltage output from the servo circuit so as to keep the added output from the adding means at a given reference voltage. In order to attain the second object, the scanning tunneling microscope of this invention further includes a scanning circuit for scanning the probe along the sample, and the scanning circuit includes means for causing the probe to scan at least a first scanning range corresponding to a portion of the sample to be observed and a second scanning range including the first scanning range and setting the size of said first scanning range; and adding means for adding output data from the setting means and data relating to a reference position of the first scanning range, corresponding to a reference position of the second scanning range, to each other in a digital manner. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate presently preferred embodiments of the invention, and together with the general description given above and the detailed description of the preferred embodiments given below, serve to explain the principles of the invention. FIG. 1 is a block diagram schematically showing the circuit construction of an STM; FIG. 2 is a block diagram of a distance adjusting circuit showing a first embodiment of this invention; FIG. 3A to 3E are diagrams for illustrating the automatic approaching method in the first embodiment of this invention; FIG. 4 is a block diagram of a distance adjusting circuit showing a second embodiment of this invention; FIG. 5 is a circuit diagram of an amplification switching circuit; FIGS. 6 and 7 are diagrams showing a method of amplifying and displaying real time cross-section images in the second embodiment; FIGS. 8, 9A, 9B, 9C, and 10 are diagrams for illustrating a method of re-scanning part of a sample having a slanted surface in the second embodiment; FIG. 11 is a block diagram of a distance adjusting circuit showing a third embodiment of this invention; FIGS. 12 and 13 are diagrams for illustrating the operation of the third embodiment; FIG. 14 is a block diagram schematically showing the circuit construction of an STM according to a fourth embodiment of this invention; and FIG. 15 is a block diagram showing the detail construction of a scanning circuit shown in FIG. 14; and FIG. 16 is a diagram for illustrating the operation of the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS There will now be described embodiments of this invention with reference to the accompanying drawings. FIG. 1 shows the construction of an STM (scanning tunneling microscope) according to this invention. In FIG. 1, 1 denotes a 8-bit CPU (central processing unit) controller for controlling the whole portion of the STM. The 8-bit CPU controller 1 is connected to an interface controller 2 and to a host computer 100 via an interface (GPIB). The 8-bit CPU controller 1 is connected to a Y-stage moving pulse motor driver (P.M.D) 3, an X-stage moving P.M.D 4, an STM scanning circuit 5, a Z-stage moving P.M.D 6, a 12-bit A/D converter 7 for subjecting a detection signal of tunnel current or Z electrode voltage signal to the A/D (analog/digital) conversion, a 10-bit D/A converter 8 for bias voltage application, and a 16-bit D/A converter 31 for Z voltage addition via respective 8-bit data buses. The 16-bit D/A converter 31 converts binary data supplied from the 8-bit CPU controller 1 via the 8-bit data bus into an analog signal (ZD/A output). The Y-stage moving P.M.D 3 drives a Y-stage moving P.M. 9 according to a driving signal (pulse data) from the 8-bit CPU controller 1 and moves the Y stage 10 in a Y direction (a direction perpendicular to the paper in the drawing). The X-stage moving P.M.D 4 drives an X-stage moving P.M. 11 according to a driving signal from the 8-bit CPU controller 1 and moves the X stage 12 in an X direction (a horizontal direction in the drawing). The Z-stage moving P.M.D 6 drives a Z-stage moving P.M. 13 according to a driving signal from the 8-bit CPU controller 1 and moves the Z stage 14 in a Z direction (a vertical direction in the drawing). A tube scanner (piezoelectric driver) 15 constituting an actuator which can be moved in a 3-dimensional direction is mounted on the bottom surface of the Z stage 14, and a tunnel probe 16 used as a metal probe having a sharp tip end is supported on the bottom surface of the tube scanner 15. The tunnel probe 16 is mounted to be supplied with a bias voltage (V) by means of the 10-bit D/A converter 8. On the other hand, a sample 17 is disposed on the top surface of the X stage 12 which faces the Z stage 14. A tunnel current (I) flows in the sample 17 when a preset bias voltage is applied thereto with the tunnel probe 16 set as close as approx. 1 nm to the surface of the sample. The tunnel current flowing in the sample 17 is supplied to a servo circuit 19, 12-bit A/D converter 7 and approach detection/instantaneous contraction circuit 32 via a tunnel current amplifying pre-amplifier 18. The servo circuit 19 creates such a Z electrode voltage signal (Z servo voltage) for keeping the distance between the tunnel probe 16 and the sample 17 constant based on a detection signal of the tunnel current supplied via the pre-amplifier 18, and outputs the same to the 12-bit A/D converter 7 or Z voltage adder (addition circuit) 33. The servo circuit 19 is constituted by a PI control circuit for creating a Z servo voltage (for example, -10 V to +10 V) and an analog switching circuit for selecting the destination to which the Z servo voltage is supplied. The adder 33 adds a ZD/A output from the 16-bit D/A converter 31 and a Z servo voltage output from the servo circuit 19 together and outputs the addition result to the approach detection/instantaneous contraction circuit 32. The approach detection/instantaneous contraction circuit 32 selects one of an addition output from the adder 33 and a maximum contraction voltage which is previously determined to cause the tube scanner 15 to be in a maximum contracted state and outputs the selected signal to a Z electrode applying high voltage amplifier (H.V.Z) 20. The approach detection/instantaneous contraction circuit 32 is constituted by an analog switching circuit 132 (FIG. 2) for selecting one signal and a flip-flop circuit 133 (FIG. 2) for instantaneously setting the analog switching circuit to the maximum contraction voltage position when it is detected that a tunnel current is produced from the pre-amplifier 18 when the tunnel probe 16 has approached the surface of the sample 17. The H.V.Z 20 amplifies an output of the approach detection/instantaneous contraction circuit 32 by ten times, for example, and applies the amplified output to the tube scanner 15. As a result, the tube scanner 15 is expanded or contracted to change the distance between the tunnel probe 16 and the sample 17. In this case, the length of the tube scanner 15 is set as a reference length when a signal (Vz) applied to the Z electrode is 0 V, and the tube scanner 15 is contracted by 1 μm by application of -100 V and expanded by 1 μm by application of +100 V. As shown in FIG. 2, the 12-bit A/S converter 7 includes an A/D converter 7a for converting an input signal to digital (binary) data and outputting the converted data to the CPU controller 1 and a real time line memory circuit 7b for storing the digital data converted by the A/D converter, and the digital data is displayed on a monitor TV 34 as a real time cross-section image. The STM scanning circuit 5 effects the count up/down operation according to a scanning starting signal supplied from the 8-bit CPU controller 1 via the 8-bit data bus to create a scanning signal in the X direction and a scanning signal in the Y direction. An X scanning 16-bit D/A converter 21 to which the scanning signal in the X direction is supplied creates an analog voltage signal (X application voltage) corresponding to an input and outputs the same to a -X electrode application high voltage amplifier (H.V.-X) 24 via a +X electrode application high voltage amplifier (H.V.+X) 22 and an inverter circuit 23. When the +X application voltage and -X application voltage are applied to the tube scanner 15 via the H.V.+X 22 and H.V.-X 24, respectively, the tube scanner 15 is deformed so as to cause the tip end of the tunnel probe 16 to scan the surface of the sample 17 in the X direction. A Y scanning 16-bit D/A converter 25 to which the scanning signal in the Y direction is supplied creates an analog voltage signal (Y application voltage) corresponding to an input and outputs the same to a -Y electrode application high voltage amplifier (H.V.-Y) 28 via a +Y electrode application high voltage amplifier (H.V. +Y) 26 and an inverter circuit 27. When the +Y application voltage and -Y application voltage are applied to the tube scanner 15 via the H.V.+Y 26 and H.V.-Y 28, respectively, the tube scanner 15 is deformed so as to cause the tip end of the tunnel probe 16 to scan the surface of the sample 17 in the Y direction. FIG. 2 shows a scanning system in the Z direction which is taken out as a distance adjusting circuit in the first embodiment of this invention. In FIG. 2, 1a denotes a CPU serving as a control circuit constituting the 8-bit CPU controller 1. 7a denotes an A/D converter, 7b denotes a real time line memory circuit, and the A/D converter 7a and real time line memory circuit 7b are combined to constitute the 12-bit A/D converter 7. Next, the automatic approaching method by use of the above construction is explained. First, a ZD/A output of the 16-bit D/A converter 31 is set to 0 V by the control operation of the CPU 1a. The analog switching circuit of the servo circuit 19 is turned off to prevent a Z servo voltage from being output to the adder 33. Further the approach detection/instantaneous contraction circuit 32 is set to select an addition output from the adder 33. As a result, a voltage (Vz) applied to the tube scanner 15 via the H.V.Z 20 is set to 0 V. Thus, as shown in FIG. 3A, the tube scanner 15 is set to the reference length. If the Z stage moving P.M.D 6 is controlled by the CPU 1a in this condition, the P.M. 13 is driven to move the Z stage in the downward direction. Then, the tube scanner 13 is lowered by the movement of the Z stage 14, thus setting the tunnel probe 16 close to the sample 17. In this case, as shown in FIG. 3B, the tunnel probe 16 is gradually moved according to the resolution (for example, 0.1 μm) of the P.M. 13. Assume that a tunnel current caused by application of a bias voltage is detected at the approaching time. Then, the downward movement of the Z stage 14 by the P.M. 13 is stopped and the analog switching circuit in the approach detection/instantaneous contraction circuit 32 is switched to a position of maximum contraction voltage (-10 V). Therefore, a voltage (Vz=-100 V) which is amplified by 10 times by means of the H.V.Z 20 is applied to the tube scanner 15. As a result, as shown in FIG. 3C, the tube scanner 15 is instantaneously contracted. However, only the Z stage 14 is stopped in position where it is lowered by Δ because of the resolution of the P.M. 13. Further, at this time, the analog switching circuit of the Z servo circuit 19 is turned on to permit a Z servo voltage to be applied to the adder 33. Then, a ZD/A output of the 16-bit D/A converter 31 is set to -10 V by control of the CPU 1a. Therefore, the tube scanner 15 is applied with a voltage Vz (-10 V) which is obtained by amplifying an addition output of a ZD/A output (-10 V) of the 16-bit D/A converter 31 and a Z servo voltage (+9 V) from the servo circuit 19 by 10 times by means of the H.V.Z 20. As a result, as shown in FIG. 3D, the tube scanner 15 is expanded nearly to the reference length and thus set into the tunnel region. However, the length of the tube scanner 15 is shorter than the reference length by 0 to 0.1 μm because of the resolution of the P.M. 13. After this, the ZD/A output of the 16-bit D/A converter 31 is controlled by the CPU 1a while the servo voltage from the servo circuit 19 is being read by the CPU 1a via the A/D converter 7. Then, when the servo voltage is set to 0 (reference voltage), the ZD/A output of the 16-bit D/A converter 31 is fixed. As a result, as shown in FIG. 3E, a state in which a voltage Vz (-10 V) obtained by amplifying an addition output of the ZD/A output (-1 V) from the 16-bit D/A converter 31 and the Z servo voltage (0 V) from the servo circuit 19 by 10 times by means of the H.V.Z 20 is applied is maintained. When the Z servo voltage is 0 V, irregularity data with 0 set as its center can be derived by scanning if the input dynamic range of the A/D converter 7a is set from -10 V to +10 V. In this case, an image with the central horizontal line set as a reference is displayed as a real time cross-section image on the monitor TV 34. As described above, in this invention, the tunnel probe 16 is set closer to the sample 17 by using a rough moving mechanism such as the P.M. 13 which effects the stepwise movement and the tube scanner 15 is instantaneously contracted immediately after it is set into the tunnel region and the rough movement is interrupted. At this time, application of the Z servo voltage is started to expand the tube scanner 15 to substantially the reference length, thus setting up the servo state. Next, deviation of the application voltage Vz from the reference voltage due to the resolution of the rough movement in the above state can be corrected (subjected to the Z servo voltage adjustment) by adjusting the ZD/A output. Further, according to this method, the STM operation can be started at a high speed in comparison with a case wherein the approaching operation is effected by repeatedly effecting the rough and fine movements. FIG. 4 shows a scanning system in the Z direction taken as distance adjusting means in a second embodiment of this invention. In FIG. 4, 7a denotes an A/D converter, 7b denotes a real time line memory circuit and 7c denotes an amplification switching circuit acting as a variable amplifier, and the A/D converter 7a, real time line memory circuit 7b and amplification switching circuit 7c are combined to constitute a 12-bit A/D converter 7. As shown in FIG. 5, for example, the amplification switching circuit 7c is constructed mainly by an analog multiplexer 71 for selecting various resistors and an inverting type amplifier 72 and amplifies a Z servo voltage supplied from the servo circuit 15 by 2 n (n=0 to 4). Selection by the analog multiplexer 71 is effected according to a selection signal from the CPU 1a. Next, a method of amplifying and displaying a real time cross-section image in the above construction is explained. In a case where an irregular portion to be observed is previously determined, the tunnel probe 16 is first approached to the portion by the above method and then scanned by one line in the X and Y directions. A real time cross-section image obtained at this time is displayed on the monitor TV 34 and therefore whether the target irregular portion can be correctly approached or not can be determined by observing the real time cross-section image. When the real time cross-section image displayed on the monitor TV 34 shows that variation in the irregularity is small as shown in FIG. 6, the amplification factor of the amplification switching circuit 7c is changed by the CPU 1a. After this, a one-line scanning operation is effected again. As a result, as shown in FIG. 7, a real time cross-section image in which the target irregular portion is enlarged in the Z direction according to the amplification factor of the amplification switching circuit 7c is displayed on the monitor TV 34. That is, when the irregularity is small, for example, when variation in the Z servo voltage is small, the servo voltage is amplified with ±0 V set as the center of the variation and then supplied to the A/D converter 7a . Thus, it is possible to easily determine whether the target irregular portion is correctly approached or not. In a case where the amplification factor of the amplification switching circuit 7c is set to x16, irregularity data having substantially the sam resolution as data which is derived by an A/D converter having a resolution of 16 bits can be obtained. In this way, data of high resolution can be obtained from the sample even if the irregularity thereof is small by correcting the offset component to set the Z servo voltage to 0 V according to the ZD/A output without amplifying the offset component to cause a saturated state. Next, with the above construction, there is explained a case where the scanning range for a slanted sample 17 is narrowed and the scanning operation is effected again after the scanning center position is moved. For example, assume that, as shown in FIG. 8, the tunnel probe 16 which is set under the servo condition is moved in the right direction in the drawing by 3.75 μm from the central position of of an area of 10 μmo on the slanted sample 17 and then the operation of scanning an area of 2.5 μmu is effected again with the above set position used as a scanning center position. In this case, the scanning counter circuit 5 is controlled by the 8-bit CPU controller 1 so as to output scanning signals in the X and Y directions which respectively correspond to a deviation amount (3.75 μm) from the center of the area of 10 μm□ and the range (2.5 μm) of rescanning. Then the tube scanner 15 is deformed by application of the voltages corresponding to the scanning signals so that the tunnel probe 16 can be moved while it is kept under the servo condition. At this time, since the sample 17 is slanted, the tube scanner 15 is contracted by ΔZ as shown in FIGS. 9A and 9B. That is, a state in which the ZD/A output of the 16-bit D/A converter 31 is set at -1 V and the servo voltage of the servo circuit 19 is set at 0 V and as a result the voltage Vz (-10 V) amplified by 10 times by the H.V.Z 20 is applied to the tube scanner 15 (refer to FIG. 9A) is changed into a state in which the Z servo voltage is set at -4 V and as a result the voltage Vz applied to the tube scanner 15 is set to -50 V (refer to FIG. 9B). In this state, as described in the automatic approaching method, the ZD/A output of the 16-bit D/A converter 31 is changed in a negative direction to change the Z servo voltage towards 0 V. Then, when the Z servo voltage is set at 0 , the ZD/A output of the 16-bit D/A converter 31 is fixed. That is, as shown in FIG. 9C, the Z servo voltage is changed from -4 V to 0 V and the ZD/A output is changed from -1 V to -5 V, but the same voltage Vz -50 V is applied to the tube scanner 15. As a result, even if the irregularity is small as shown by a in FIG. 10, data can be taken by the A/D converter 7a after the servo voltage is amplified with ±0 V set as the center of the variation. Thus, as shown by b in FIG. 10, data (real time cross-section image) of high resolution can be obtained for the range of 2.5 μm□. FIG. 11 shows a scanning system in the Z direction as a distance adjusting circuit in a third embodiment of this invention. In this embodiment, the STM is used as an STS for measuring the physical property of the surface (electron state density of the sample surface) of the sample 17 by modulating the distance between the tunnel probe 16 and the sample 17 and deriving a tunnel current. That is, in the case of this distance adjusting circuit, the 8-bit CPU controller 1 includes a Z modulation pattern data generator lb as a modulation pattern generating circuit in addition to the CPU la used as a control circuit. Further, the 12-bit A/D converter 7 includes an A/D converter 7a , real time line memory circuit 7b, amplification switching circuit 7c and signal selection circuit 7d. The Z modulation pattern data generator 1b includes an up/down counter circuit having a counting range of, for example, "0000 H " to "000F H ", "001F H " and "003F H " and changes the up/down counting range according to the modulation range of the tunnel probe 16. Output binary data of the counter circuit is supplied to the 16-bit D/A converter 31 to finely modulate the ZD/A output of the 16-bit D/A converter 31. The start and interruption of the operation and change of the counting range in the Z modulation pattern data generator 1b can be controlled by signals from the CPU 1a. The signal selection circuit 7d selects one of the Z servo signal (irregularity data) and a detection signal (converted into voltage) of tunnel current according to a signal from the CPU 1a and outputs the same to the amplification switching circuit 7c. Further, a switching circuit only for PI control/I control and an I control gain switching circuit are additionally provided in the servo circuit 19. Next, a method for measuring the electron state density of the sample surface with the above construction is explained First, the servo circuit 19 is switched to the I control circuit under the control of the CPU 1a and the (integration control) gain of the I control circuit is set to sufficiently follow the irregularity of the surface of the sample 17. Then, the Z modulation pattern data generator 1b is controlled to be operated at a frequency relatively higher than roughness at which the image varies, that is, the space frequency to be followed by the I control, thus making it possible to modulate the ZD/A output of the 16-bit D/A converter 31 at a relatively high speed in comparison with the time constant of the servo circuit 19. After this, the Z servo voltage from the servo circuit 19 and the ZD/A output from the 16-bit D/A converter 31 are added together by an adder 33. Then, the added output of the adder 33 is amplified by the H.V.Z 20 and applied to the tube scanner 15. In this state, the X-Y scanning operation is effected. Then, the tip end of the tunnel probe 16 is moved on the surface of the sample 17 along a locus shown in FIG. 12. At this time, a signal to be taken by the A/D converter 7a is switched from the Z servo voltage to the detection signal of tunnel current by controlling the signal selection circuit 7d. The electron state density of the sample surface can be measured by sampling signal data at points indicated in FIG. 13. The tip end modulation sequence is well known in the art as a method for measuring the electron state density of the sample surface and its operation can be adjusted programmably by use of the distance adjusting circuit of this invention. Thus, it can be used as an STS by deriving a detection signal of tunnel current in accordance with modulation of the ZD/A output of the 16-bit D/A converter 31. As described above, a servo control suitable for the surface condition of the sample can be effected by operating the distance adjusting circuit in accordance with the surface condition obtained by the tunnel current. That is, deviation of an application voltage from the reference voltage in the Z direction caused by the resolution of the rough moving mechanism when the tunnel probe is approached to the surface of the sample can be corrected by applying a voltage which causes the servo voltage to be set to 0 V. As a result, the operation for the approach of the tunnel probe can be simplified and the distance between the tunnel probe and the sample can be servo-controlled in accordance with the surface condition of the sample. Therefore, since irregularity data with 0 V set as its center can be derived in the scanning operation, reduction in the resolution of the real time cross-section image and deviation of the dynamic range from its center can be prevented. Further, since irregularity data with 0 V set as its center can be derived, variation in the small irregularity of the sample surface can be enlarged and displayed by amplifying the irregularity data. In addition, since the distance between the tunnel probe and the sample can be servo-controlled in accordance with the surface condition of the sample, it can be used as an STS for measuring the electron state density of the sample surface by modulating the distance between the tunnel probe and the sample In the above embodiment, the probe is mounted so as to be supported by the piezoelectric driver, but this is not limitative and it is possible to support the sample. Next, a fourth embodiment of this invention which is improved over the STM scanning circuit 5 is explained with reference to FIG. 14. In FIG. 14, portions which are the same as those of FIG. 1 are denoted by the same reference numerals. Therefore, the explanation therefor is omitted, but in this embodiment, a Z electrode voltage signal (Z servo voltage) from a servo circuit 19 is directly supplied to a 12-bit A/D converter 7 and a Z electrode applying high voltage amplifier (H.V.Z.) 20. The Z servo voltage is applied to the tube scanner 15 via the H.V.Z. 20 to expand and contract the tube scanner 15 so as to keep the distance between the probe 16 and the surface of a sample 17 constant. In this embodiment, the STM scanning circuit 5 is constituted mainly by a bit shift circuit and a digital adder. That is, the STM scanning circuit 5 includes a scanning counter circuit (scanning 16-bit output counter) 51 for effecting the counting up/down operation in response to a scanning signal supplied from an 8-bit CPU controller 1 via a CPU data bus, a bit shift circuit (scanning range switching bit shifter) 52 for shifting an output of the scanning counter circuit 51 to the LSB (Least Significant Bit) side by a desired bit number according to a shift number signal (range setting data) supplied from the 8-bit CPU controller 1, latch circuits (scanning offset 16-bit data latch circuits) 53 and 54 for latching scanning offset values (reference position data) supplied from the 8-bit CPU controller 1, a digital adder 55 for creating a scanning signal in the X direction, for example, by adding an output of the latch circuit 53 and an output of the bit shift circuit 52 together, and a digital adder 56 for creating a scanning signal in the Y direction, for example, by adding an output of the latch circuit 54 and an output of the bit shift circuit 52 together. An output of the digital adder 55 is supplied to an X-scanning 16-bit D/A converter 21. The X-scanning 16-bit D/A converter 21 creates an analog voltage output (X application voltage) corresponding to an input and outputs the same to a -X electrode applying high voltage amplifier (H.V.-X) 24 via a +X electrode applying high voltage amplifier (H.V.+X) 22 and an inverter circuit 23. When the +X application voltage and -X application voltage are applied to the tube scanner 15 via the H.V.+X 22 and H.V.-X 24, respectively, the tube scanner 15 is deformed by application of the voltages so that the tip end of the probe 16 can scan a desired scanning area on the surface of the sample 17 in the X direction according to the scanning starting position corresponding to the reference position data An output of the digital adder 56 is supplied to a Y-scanning 16-bit D/A converter 25. The Y-scanning 16-bit D/A converter 25 creates an analog voltage output (Y application voltage) corresponding to an input and outputs the same to a -Y electrode applying high voltage amplifier (H.V.-Y) 28 via a +Y electrode applying high voltage amplifier (H.V.+Y) 26 and an inverter circuit 27. When the +Y application voltage and -Y application voltage are applied to the tube scanner 15 via the H.V.+Y 26 and H.V.-Y 28, respectively, the tube scanner 15 is deformed by application of the voltages so that the tip end of the probe 16 can scan a desired scanning area on the surface of the sample 17 in the Y direction according to the scanning starting position corresponding to the reference position data In this way, in this invention, the scanning range and the scanning starting position thereof can be changed without separating the probe 16 from the sample 17 or using a digital addition output of a rough moving mechanism by using an output of the bit shifter to which range setting data is input and the reference position data as a scanning signal. FIG. 15 shows the construction of the STM scanning circuit 5 in more detail. For convenience, only a scanning system in the X direction is shown and explained in this example. An X scanning counter circuit 51a repeatedly effects the count up/down operation between "0000 H " and "FFFF H " according to the scanning starting signal from the 8-bit CPU controller 1 by a number of times equal to the number of scanning lines and stops the counting operation when "0000 H " is reached. An X scanning count bit shift circuit 52a shifts a 16-bit count value supplied from the X scanning counter circuit 51a to the LSB side by a bit number corresponding to a shift number signal from the 8-bit CPU controller 1 and outputs data (output count value) having "0" set into a vacant bit or bits of the MSB side to the X count value digital adder 55. That is, in the X scanning count bit shift circuit 52a, in a case where a count value from the X scanning counter circuit 51a is "FFFF H ", for example, "7FFF H " is output as an output count value when a 1-bit shift is set and "3FFF H " is output as an output count value when a 2-bit shift is set. Thus, the output count value from the X scanning count bit shift circuit 52a is set to 1/2, 1/4, 1/8, --of a count value supplied from the X scanning counter circuit 51a by changing the setting of the bit shift number. Therefore, when the 1-bit shift is set, the X scanning count value becomes equal to a value obtained by repeatedly effecting the counting operation between "7FFF H " and "0FFF H " by a number of times corresponding to a scanning line number in the output of the digital adder 55. The X count value digital adder 55 is constituted by an upper digit side digital adder 55a and a lower digit side digital adder 55b, and divides an X scanning offset value set into a scanning offset 16-bit data latch circuit 53 by the 8-bit CPU controller 1 and an output count value supplied from the X scanning count bit shift circuit 52a into the upper digit portion and lower digit portion and add them together in respective digit sides. That is, in the upper digit side digital adder 55a, the upper 8 bits of the offset value supplied from an upper digit side latch circuit 53a of the latch circuit 53 and the upper 8 bits of an output count value supplied from the X scanning count bit shift circuit 52a are added together. Likewise, in the lower digit side digital adder 55b, the lower 8 bits of the offset value supplied from a lower digit side latch circuit 53b of the latch circuit 53 and the lower 8 bits of an output count value supplied from the X scanning count bit shift circuit 52a are added together. Therefore, in a case where the bit shift number of the X scanning count bit shift circuit 52a is set at "1", an X scanning count which is an output of the digital adder 55 becomes equal to a value obtained by repeatedly effecting the counting operation between "4000 H " and "BFFF H " by a number of times corresponding to a scanning line number when "4000 H " is latched in the latch circuit 53 as an offset value, for example. The X scanning 16-bit D/A converter 21 to which an output of the digital adder 55 is supplied outputs an X application voltage of "0" V when it is supplied with "0000 H " as an input, for example, and outputs an X application voltage of "10" V when it is supplied with "FFFF H ". The construction described above is for a system for moving the probe 16 in the X direction, but a scanning system in the Y direction for moving the probe in the Y direction has substantially the same construction. However, in the case of the Y-direction scanning system, a Y scanning counter circuit effects the counting up/down operation between "0000 H " and "FFFF H " only once according to the scanning starting signal from the 8-bit CPU controller 1. That is, a Y scanning clock at the counting-up time has a frequency obtained by dividing the frequency of an X scanning clock (scanning line number ×2) and is changed to have the same frequency as the X scanning clock when all the lines are scanned in the X direction. Then, a counting-down operation is started and stopped when "0000 H " is reached. The scanning count bit shift circuit converts an output count value to 1/2 n times by shifting a 16-bit count value supplied from the Y scanning counter circuit by n bits. In this case, since the scanning range is square, the value of n (bit shift number) is set to the same value for the X and Y scanning. Next, the operation with the above construction is explained. In this case, an STM having the maximum scanning range of 10 μm ×10 μm is used. First, a wide scanning operation for an area of 10 μm□ is effected and a scanning operation for a scanning area of 2.5 μm□ with a desired point set as its reference after an STM image thereof is observed. For example, assume now that a scanning starting signal indicating the wide range scanning for an area of 10 μm□ is supplied from the 8-bit CPU controller 1 to the STM scanning circuit 5 via the CPU data bus while the probe 16 is servo-controlled on the scanning starting position (reference position) on the sample 17. In this case, suppose that "0" is previously set in the bit shift circuit 52 as a bit shift number according to a shift number signal from the 8-bit CPU controller 1, and "0000 H " is set in the latch circuits 53 and 54 as X- and Y-scanning offset values, respectively. Then, an X scanning count value obtained by repeatedly effecting the counting up/down operation between "0000 H " and "FFFF H " by a number of times corresponding to a scanning line number, for example, 512 time, according to the scanning starting signal is output from the STM scanning circuit 5 to the X-scanning 16-bit D/A converter 21 and a Y scanning count value obtained by effecting the counting up/down operation between "0000 H " and "FFFF H " by one time is output to the Y-scanning 16-bit D/A converter 25. Therefore, an X application voltage (0 to 10 V) corresponding to an X scanning count value supplied from the STM scanning circuit 5 is output from the X-scanning 16-bit D/A converter 21 and is applied to the tube scanner 15 as an X-direction scanning signal. Likewise, a Y application voltage (0 to 10 V) corresponding to a Y scanning count value supplied from the STM scanning circuit 5 is output from the Y-scanning 16-bit D/A converter 25 and is applied to the tube scanner 15 as a Y-direction scanning signal. As a result, the tube scanner 15 is deformed to move the tip end thereof in a range of 0 to 10 μm in the X direction and is moved in the Y direction in a range of 0 to 10 μm in each movement in the X direction. Then, as shown in FIG. 16, the probe 16 scans an area A of 10 μm□ on the sample 17. Data obtained in the scanning operation is sampled at 512 points which is the same in number as the scanning lines, for example, and an STM image thus obtained is displayed on the top-view display by means of a host computer 100, thus making it possible to observe the contour or surface state of the sample 17 in the wide scanning area of 10 μm□. In this case, the STM image is displayed in a 2-dimensional (X, Y) manner and the Z direction is displayed by variation in brightness (luminance). Assume that, when the STM image is observed, it is desired to enlarge and observe an image in an area of 2.5 μm□ having a position (desired point) which is set as a reference point and is separated from the reference position of a wide scanning area of 10 μm□ by 4000 H (2.5 μm) in the X direction and by 8000 H (5 μm) in the Y direction. In this case, a scanning starting signal defining that the scanning range is 2.5 μm×2.5 μm is output from the 8-bit CPU controller 1 to the STM scanning circuit 5. That is, the bit shift number of the bit shift circuit 52 is set to "2" by a shift number signal from the 8-bit CPU controller 1. At this time, "4000 H " is set into the latch circuit 53 as the X-scanning offset value and "8000 H " is set into the latch circuit 54 as the Y-scanning offset value. Then, in the STM circuit 5, the counting up/down operation between "0000 H " and "FFFF H " is repeatedly effected by a number of times corresponding to the scanning line number, for example, 512 times by the scanning counter circuit 51 (more precisely, the X scanning counter circuit 51a) according to the scanning starting signal and the counting result or X scanning count value is output to the bit shift circuit 52 (more precisely, X scanning count bit shift circuit 52a ). The X scanning count value is bit-shifted by the bit shift circuit 52 according to the bit shift number "2" set by the shift number signal and then output to the digital adder 55. An output from the bit shift circuit 52 or an output count value in the X direction is added together with X-scanning offset value "4000 H " set in the latch circuit 53 and then output to the X scanning 16-bit D/A converter 21. On the other hand, a Y scanning count value obtained by effecting a count up/down operation between "0000 H " to "FFFF H " by one time according to the above scanning starting signal is output from the scanning counter circuit 51 (more precisely, a Y scanning counter circuit not shown in the drawing) to the bit shift circuit 52 (more precisely, a Y scanning count bit shift circuit shot shown in the drawing). Then, in the bit shift circuit 52, the Y scanning count value is bit-shifted and is output to the digital adder 56. An output count value in the Y direction is added together with Y direction offset value "8000 H " set in the latch circuit 54 by the digital adder 56 and then output to the Y-direction 16-bit D/A converter 25. Therefore, an X application voltage (2.5 to 5.0 V) corresponding to an X scanning count value supplied from the digital adder 55 is output from the X-scanning 16-bit D/A converter 21 and is applied to the tube scanner 15 as an X-direction scanning signal. Likewise, a Y application voltage (5.0 to 7.5 V) corresponding to a Y scanning count value supplied from the digital adder 56 is output from the Y-scanning 16-bit D/A converter 25 and is applied to the tube scanner 15 as a Y-direction scanning signal. As a result, the tube scanner 15 is deformed to move the tip end thereof in a range of 2.5 μm to 5.0 μm in the X direction and is moved in a range of 5.0 μm to 7.5 μm in the Y direction for each movement in the X-direction. Thus, as shown in FIG. 16, the range (hatched portion) B of 2.5 μmo of the sample 17 is scanned by the probe 16. In this case, an STM image of partly high resolution can be obtained by sampling the scanning data at points of the same number as the scanning line number or 512 points, for example, that is, at 512 points which is the same sampling number as that used in the case of scanning the wide range of 10 μm□. As described above, the probe can be moved without being separated from the sample and part of the STM image obtained in the wide range scanning operation can be enlarged and displayed by re-scanning an area corresponding to the part of the STM image. That is, a shift number signal for setting the size of a desired scanning range after the wide range scanning operation is completed is input to the bit shifter and an addition output obtained by adding an output of the bit shifter and offset values of the X and Y directions of the desired scanning range with respect to the reference position of the wide scanning range in a digital manner is used as a scanning signal so that the scanning range and the scanning starting position can be changed without separating the probe from the sample and using a rough moving mechanism. Therefore, part of the STM image obtained in the wide range scanning operation can be enlarged and displayed by re-scanning an area corresponding to the part of the STM image without causing scars on the sample by the probe at the approaching time and receiving an influence of an error caused by the precision of the rough moving mechanism. As a result, an STM image obtained may have a higher resolution in comparison with an image which is enlarged and displayed by the image processing, making it possible to precisely reproduce variation in the actual shape and reduce the load and time for effecting the re-scanning operation. Some embodiments of this invention are explained above, but this invention is not limited to these embodiments and can be variously modified without changing the technical scope of this invention. As described above, according to this invention, a scanning type tunnel microscope can be provided in which, since the distance adjusting means is operated according to the surface condition obtained by the tunnel current, a servo system for controlling the distance between the probe and the sample can always be properly operated irrespective of the surface condition of the sample. Further, according to this invention, a scanning type tunnel microscope can be provided in which, since a digital addition output of an output of the bit shifter and reference position data is used as a scanning signal, a scanning starting position for a desired scanning range in a desired position set after the wide range scanning operation is completed can be set without using a rough moving mechanism, thereby always correctly setting the position and maintaining the reliability of an enlarged image. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, and representative devices shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

4y

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This application relates to locking mechanisms for doors, particularly doors used to separate an aircraft cockpit compartment from an aircraft passenger compartment. [0003] 2. Description of the Related Art [0004] In a commercial airliner, a door is typically provided between the cockpit and the passenger area. This is desirable for a number of reasons. The door can be locked with a lock typically being controlled by the crew in the cockpit, such as an electrically operated lock. The door gives the crew in the cockpit a measure of security from disturbances in the passenger area. Also, it isolates the crew from the noise in the passenger area, which is desirable to prevent fatigue and to facilitate concentration. Also, with the cockpit sealed, the air conditioning in the cockpit can be handled in a manner different from the passenger area. This is advantageous for crew performance. [0005] At the same time, it is necessary that the pressure differential between the cockpit and the passenger area not exceed a certain level in that a decompression condition in either area can cause serious structural damage to the airplane. Currently, this goal is accomplished by having a door locking mechanism give way when the door is subjected to a certain force, such as about 160 pounds. Unfortunately, a hijacker can fairly readily manually produce sufficient force to open the door in that fashion. Consequently, a need exists for a system that will provide the necessary privacy, prevent decompression damage, and at the same time provide the necessary security to prevent a hijacker from entering the cockpit. It is, of course, necessary that the system be practical and reliable. SUMMARY OF THE INVENTION [0006] In accordance with the invention, an aircraft door is provided with a strong locking mechanism that cannot be broken simply by manual force. The lock is controlled either by a crew member within the cockpit or a pressure sensor. The pressure sensor prevents damage to the aircraft if a decompression situation should occur in the cockpit. Decompression in the passenger area is not a concern since the amount of in-rushing air from the cockpit is small in comparison with passenger area volume. [0007] A spring loaded catch cooperates with the door bolt or latch to hold the door closed. In the event a hijacker attempts to enter the cockpit compartment by applying a load on the door and locking mechanism, a pin supports the load on the door catch and prevents the hijacker from breaking connection between the door latch and the catch. [0008] While the pin is able to withstand a force well over that which hijackers could apply, the pin can be quickly retracted from its supporting position to allow the door to overcome the spring force and swing open when a decompression event occurs in the cabin of the plane. The pin is retracted when the pressure sensor sends a signal to an actuator such as solenoid linked to the pin. [0009] The attached drawings illustrate a concept for such a mechanism. BRIEF DESCRIPTION OF THE DRAWINGS [0010] [0010]FIG. 1 shows a front view of the preferred embodiment of the locking mechanism of the invention. [0011] [0011]FIG. 2 shows a back view of the mechanism. [0012] [0012]FIG. 3 shows a right side view of the mechanism. [0013] [0013]FIG. 4 shows a left side view of the mechanism. [0014] [0014]FIG. 5 shows a perspective view of the mechanism linked to a schematically illustrated pressure sensor and control circuit. [0015] [0015]FIG. 6 shows an enlargement of the view in FIG. 5 without the support housing. [0016] [0016]FIG. 7 schematically shows a locking pin of the mechanism in an extended position. [0017] [0017]FIG. 8 shows the locking pin in a retracted position. [0018] [0018]FIG. 9 is an end view of the locking mechanism with the main support removed and with the catch engaging a latch on a door. [0019] [0019]FIG. 10 is the same as FIG. 9 with a portion of the catch broken away to see the roller carried by the catch. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0020] Referring to FIGS. 5 and 6, the latch mechanism of the invention includes a strike or catch 10 , a pin 12 , a pair of rollers 14 and 16 mounted on pins 18 , and an actuator such as a solenoid 20 , all supported on a housing or support 22 . The solenoid is controlled by a schematically illustrated pressure sensor 24 and a control circuit 25 . The latch mechanism is normally positioned vertically on a door frame aligned to allow a door bolt or latch to engage the catch 10 when a door is swung into a closed position. [0021] As seen in FIGS. 5 and 6, the catch 10 is pivotally mounted on a pin 30 mounted on the support 22 and held in a normally door closed position by the urging of a biasing element such as a spring 32 . The catch 10 is shown in FIG. 9 engaging a door latch or bolt 40 to hold a door 42 in a closed position. If, however, a force is applied against the door that exceeds the spring force, the catch 10 is rotated about the pin 30 to an unlatched position allowing the door to swing open. A door knob may be provided on the pilot compartment side to retract the latch 40 to open the door in conventional fashion. [0022] Referring to FIGS. 6 - 10 , the latch mechanism is reinforced with the pin 12 , which is connected to the solenoid 20 to prevent unintended individuals, who exert a load on the door, from entering the cockpit. If such an individual tries to force the door open by overcoming the biasing spring 32 , the catch 10 is maintained in the normal position by the pin 12 which is restrained by the roller 14 which is supported by the housing 22 . Unlike the spring 32 , the pin 12 backed by the support 22 can withstand a load greater than that which an intruder could manually produce. [0023] As important as it is in preventing individuals from compromising the security of the occupants in the cockpit, the pin 12 would prevent the door from swinging open during a decompression event. Thus, the pin 12 must be quickly removed during such a catastrophic event. This is achieved by the cooperation of the pin 12 , the solenoid 20 , and the pressure sensor 24 , and control circuit 25 . The pressure sensor detects a significant change or rate of change in air pressure in the cockpit. When a dramatic change in air pressure occurs, the sensor deactivates the solenoid 20 which retracts the pin 12 away from its extended position, as shown in FIG. 7, to a retracted position shown in FIG. 8. When the pin 12 is fully retracted, the only force holding the door in the closed position is the biasing spring 32 . However, because the pressure sensor will only send a signal to the solenoid 20 when the change in the cockpit air pressure is significant, the large load on the door will overcome the spring force and swing the door away from its closed position to equalize the air pressure between the cockpit and passenger cabin. [0024] To aid with the retraction of the pin 12 , the solenoid 20 , which is commercially available, has two opposing springs for quick response. One spring urges the solenoid rod into its normal position in which the solenoid coil is not energized and the other spring provides force to assist the electrical force on the rod when the solenoid is energized. One suitable solenoid of this type is available from Moog, Inc., in Salt Lake City, Utah. In addition, the hole 44 for the pin in the support 22 is oversized so that friction is reduced or eliminated between the pin 12 and the hole when the pin extends into and retracts from the support. Preferably, the hole is sized so that the pin 12 does not come in contact with the support. Rather, the pin 12 floats through the hole 44 in the support 22 and is guided only by the rollers 14 and 16 . The pin 18 for the roller 14 is mounted in the support 22 while the pin for the other roller 16 is mounted to the catch 10 . [0025] While the rollers 14 and 16 help maintain the proper position of the pin 12 even when a load, roughly perpendicular to the pin 12 , is applied, they also provide the added advantage of reducing drag on the pin 12 when it rapidly retracts from its extended position. When the pin 12 is caused to retract, the rollers 14 and 16 , by riding along the tapered tip of the pin 12 , work to push the pin 12 away. In addition, when the tip of the pin passes the centerline 13 of the rollers, the roller 16 will push the pin away from the swing path of the catch 10 . [0026] The angle a of the slope on the tip of the pin 12 is preferably between 4 to 6 degrees for the purpose of assisting with the decompression event. However, one of ordinary skill in the art can appreciate that the angle a can be modified. The angle α is dependent on the size of the rollers 14 and 16 and their respective pivot pins 18 , as well as the friction coefficient and holding force of the solenoid 20 . [0027] Based on decompression testing using the preferred embodiment, having a pin 12 design with sloped sides of 4 to 6 degrees, the door should be fully free to move within 4 to 12 milliseconds. The response time is dependent on the type of door and bolt. TABLE 1 Decompression Test Configurations PSI Mylar Pattern Door Test Differential (Opening) Configuration Bolt Material 1 2 Circular First Nylon 2 3 Circular First Nylon 3 3 Square First Nylon 4 3 Circular Second 17-4 55 5 3 Circular Second 17-4 SS [0028] Five separate tests were conducted on the preferred embodiment. As shown in Table 1, each test varied based on the amount of pressure applied, the mylar pattern employed, and the type of door and bolt used. To obtain a decompression event, mylar was burned enough to create a “full aperture.” At that moment, the solenoid was caused to move triggering the pin to retract from supporting the catch. Table 2 provides the test results from the experiment. The results track the amount of time, in milliseconds, it took for: (1) the mylar to burn enough to create a “full aperture” (T FA ); (2) the solenoid to begin moving after full aperture (T SS ); (3) the pin to begin moving after the solenoid began moving (T LSM ); (4) the solenoid to reach full travel after the pin began to move (T FT ); and (5) the door to be free of the pin after the solenoid reached full travel (T DF ). TABLE 2 Results from a Decompression Test showing Elapsed Time in Milliseconds Test T FA T SS T LSM T FT T DF 1 5.0 1.0 3.0 1.0 4.0 2 5.0 1.0 2.0 1.0 2.0 3 6.0 0.0 4.0 1.0 7.0 4 5.0 0.0 0.0 2.0 3.0 5 6.0 0.0 1.0 2.0 2.0 Average 5.4 0.4 2.0 1.4 3.6 [0029] Based on the results of the testing, the average time it took after a decompression event for the solenoid to begin moving and triggering the pin was approximately 0.4 milliseconds. From that point, it took approximately 2.0 milliseconds for the pin to begin moving and 3.4 milliseconds for the solenoid to reach full travel. The average time it took for the door to be free of the strike after decompression was approximately 7.4 milliseconds. [0030] As one of ordinary skill in the art can appreciate, the preferred embodiment is designed in such a way to respond with sufficient speed to deal with a decompression event. In addition, it is designed to provide the necessary support to maintain a cockpit door in a closed position even when an attempt is made to force the door open by an uninvited individual. [0031] Although the foregoing invention has been described in terms of a preferred embodiment, other embodiments will become apparent to those of ordinary skill in the art, in view of the disclosure herein. Accordingly, the present invention is not intended to be limited by the recitation of the preferred embodiment, but is instead intended to be defined by reference to the appended claims.

4y

CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of U.S. patent application Ser. No. 11/147,508, filed Jun. 8, 2005, entitled “Shadowmask Deposition Of Materials Using Reconfigurable Shadowmasks”. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an electronic circuit element and, more particularly, to an electronic circuit element formed from layers of different segments deposited on a substrate by way of a shadow mask deposition process. [0004] 2. Description of Related Art [0005] Electronic circuits with repetitive patterns, such as memories and imaging or display devices are, widely used in LED industry. Presently, such circuits are formed by photolithographic processes. [0006] A shadow mask deposition process is well-known and has been used for years in micro-electronics manufacturing. The shadow mask process is a significantly less costly and less complex manufacturing process compared to the photolithography process. Accordingly, it would be desirable to utilize the shadow mask deposition process to form electronic circuits. [0007] One problem with the current shadow mask deposition process is the need to engineer, manufacture and inventory a large number of shadow masks, each of which typically has one or more apertures of a unique size and/or location in the shadow mask. Thus, for example, if a plurality of shadow mask deposition events is required to produce the electronic elements of an electronic circuit having a repetitive pattern, a plurality of different shadow masks is typically required, since each deposition event will typically entail the deposition of material of a unique size and/or a unique location on the substrate. [0008] It would, therefore, be desirable, to overcome the above problem and others by providing shadow masks that have configurable opening sizes whereupon the need to engineer, manufacture and inventory a unique shadow mask for each deposition event is avoided. SUMMARY OF THE INVENTION [0009] The present invention is an electronic circuit with repetitive patterns formed by shadow mask vapor deposition. The electronic circuit includes a repetitive pattern of electronic circuit elements formed on a substrate. Each electronic circuit element includes a substrate; a first semiconductor segment deposited on a portion of the substrate; a second semiconductor segment deposited on a different portion of the substrate; a first metal segment deposited on the substrate over a portion of the first semiconductor segment; a second metal segment deposited on the substrate over a different portion of the first semiconductor segment spaced from the first metal segment; a third metal segment deposited on the substrate over a portion of the second semiconductor segment; a fourth metal segment deposited on the substrate over a different portion of the second semiconductor segment spaced from the third metal segment; a fifth metal segment deposited on the substrate over at least a portion of the fourth metal segment; a sixth metal segment deposited on the substrate over at least a portion of the first metal segment; a first insulator segment deposited on the substrate over the first semiconductor segment, at least a portion of the first metal segment and at least a portion of the second metal segment; a second insulator segment deposited on the substrate over at least a portion of the fifth metal segment; a third insulator segment deposited on the substrate over the second semiconductor segment and at least portions of the third metal segment, the fourth metal segment and the fifth metal segment; a seventh metal segment deposited on the substrate over at least a portion of the first insulator segment; an eighth metal segment deposited on the substrate over at least portions of the first insulator segment, the second insulator segment and the seventh metal segment; a ninth metal segment deposited on the substrate over at least portions the second metal segment and the third insulator segment; and a tenth metal segment deposited on the substrate over at least portions the third insulator segment and the ninth metal segment. [0010] All of the above segments may be deposited via a shadow mask deposition process. One or more of the first and second semiconductor segments, the first, second, third, fifth, sixth, seventh and eighth metal segments and the first insulator segment may have an elongated shape, and one or more of the fourth, ninth and tenth metal segments and the second and third insulator segments may have a rectangular shape. One or more of the first and second semiconductor segments may be formed from a semiconductor material that is suitable for forming a thin-film transistor by vacuum evaporation such as, but not limited to, cadmium selenide (CdSe), cadmium sulfide (CdS) or tellurium (Te). One or more of the metal segments may be formed of any suitable electrically conductive material, such as, but not limited to, molybdenum (Mo), copper (Cu), nickel (Ni), chromium (Cr), aluminum (Al), gold (Au) or indium-tin oxide (ITO). One or more of the insulator segments may be formed of any suitable electrically nonconductive material, such as, but not limited to, aluminum oxide (Al 2 O 3 ) or silicon dioxide (SiO 2 ). The substrate may be formed of an electrically insulative material. [0011] The combination of the second semiconductor segment, the third, fourth and tenth metal segments and the third insulator segment may form a first transistor. The combination of the first semiconductor segment, the first, second, seventh, and eighth metal segments and the first insulator segment may also form a second transistor. The electronic circuit element may be an element of an array of like electronic circuit elements. [0012] The present invention is also an electronic circuit element of an electronic circuit comprising a first stack of materials, a second stack of materials operatively connected to the first stack and a third stack of materials operatively connected to the first stack and the second stack. The first stack of materials includes a first semiconductor material layer, a first conductive material layer overlaying a first part of the semiconductor material layer, a second conductive material layer overlaying a second part of the semiconductor material layer spaced from the first part thereof, an insulator material layer overlaying the first semiconductor material layer and the first and second conductive material layers, and a third conductive material layer overlaying at least a portion of the insulator material layer. The second stack of materials includes a first conductive material layer, an insulator material layer overlaying at least a portion of the first conductive material layer, and a second conductive material layer overlaying at least a portion of the insulator material layer and in contact with the third conductive material layer of the first stack of materials. The third stack of materials includes a second semiconductor material layer, a first conductive material layer overlaying a first part of the second semiconductor material layer, a second conductive material layer overlaying a second part of the second semiconductor material layer spaced from the first part thereof, an insulator material layer overlaying the second semiconductor material layer and the first and second conductive material layers in alignment with the second semiconductor material layer, a third conductive material layer overlaying the insulator material layer, and a fourth conductive material layer overlaying a portion of the third conductive material layer and a portion of the second conductive material of the first stack of materials. [0013] Lastly, the present invention is a method of manufacturing an electronic circuit element, comprising providing a substrate; depositing a first semiconductor segment on a portion of the substrate; depositing a second semiconductor segment on a different portion of the substrate; depositing a first metal segment on the substrate in contact with a portion of the first semiconductor segment; depositing a second metal segment on the substrate in contact with another portion of the first semiconductor segment spaced from the first metal segment; depositing a third metal segment on the substrate in contact with a portion of the second semiconductor segment; depositing a fourth metal segment on the substrate in contact with another portion of the second semiconductor segment spaced from the third metal segment; depositing a fifth metal segment on the substrate in contact with a portion of the fourth metal segment; depositing a sixth metal segment on the substrate in contact with a portion of the first metal segment; depositing a first insulator segment on the substrate over the first semiconductor segment, and portions of the first metal segment and the second metal segment in contact with the first semiconductor segment; depositing a second insulator on the substrate over a portion of the fifth metal segment spaced from the fourth metal segment; depositing a third insulator segment on the substrate over the second semiconductor segment and at least portions of the third metal segment, the fourth metal segment and the fifth metal segment; depositing a seventh metal segment on the substrate over at least a portion of at least one of the first insulator segment and the second insulator segment; depositing an eighth metal segment on the substrate over at least a portion of at least one of the first insulator segment and the second insulator segment and in contact with at least a portion of the seventh metal segment; depositing a ninth metal segment on the substrate over at least portions of the second metal segment and the third insulator segment; and depositing a tenth metal segment on the substrate over the third insulator segment and in contact with at least a portion of the ninth metal segment. [0014] An insulating material may be deposited over the substrate such that only a portion of the third metal segment is exposed through an opening in said insulating material. An eleventh metal segment may be deposited over the insulating material and in contact with the third metal segment. A light emitting material may be deposited in contact with the eleventh metal segment. [0015] Each segment may be deposited via a shadow mask deposition process. One or more of the semiconductor segments may be formed from cadmium selenide (CdSe), cadmium sulfide (CdS) or tellurium (Te). One or more of the metal segments may be formed from molybdenum (Mo), copper (Cu), nickel (Ni), chromium (Cr), aluminum (Al), gold (Au) or indium-tin oxide (ITO). One or more of the third insulator segments may be formed of one of aluminum oxide (Al 2 O 3 ) and silicon dioxide (SiO 2 ). The combination of the second semiconductor segment, the third, fourth and tenth metal segments and the third insulator segment may form a transistor. The combination of the first semiconductor segment, the first, second, seventh, and eighth metal segments and the first insulator segment may form another transistor. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1A is a diagrammatic illustration of a shadow mask deposition system for forming pixel structures of a high resolution active matrix backplane; [0017] FIG. 1B is an enlarged view of a single deposition vacuum vessel of the shadow mask deposition system of FIG. 1A ; [0018] FIG. 2 is a circuit schematic of a 3×3 array of sub-pixels of an active matrix backplane wherein a 2×2 array of said 3×3 array define a pixel of said active matrix backplane; [0019] FIG. 3 is an enlarged view of an exemplary physical layout of one of the sub-pixels of FIG. 2 ; [0020] FIG. 4 is a view of an exemplary physical layout of the sub-pixel structures that form the sub-pixels of FIG. 2 ; [0021] FIG. 5A is a view of a portion of a compound shadow mask utilized in the shadow mask deposition system of FIG. 1A atop a substrate upon which is deposited a plurality of segments of the sub-pixel structures shown in FIG. 4 through openings in the compound shadow mask; [0022] FIG. 5B is an exploded sectional view taken along lines VB-VB in FIG. 5A ; [0023] FIG. 5C is an exploded sectional view taken along lines VC-VC in FIG. 5A ; and [0024] FIGS. 6-19 are views of a sequence of openings in compound shadow masks of the shadow mask deposition system of FIG. 1A through which a plurality of materials is deposited to form the sub-pixel element shown adjacent each opening. DETAILED DESCRIPTION OF THE INVENTION [0025] The present invention will be described with reference to the accompanying figures where like reference numbers correspond to like elements. [0026] With reference to FIGS. 1A and 1B , a shadow mask deposition system 2 for forming an electronic device, such as, without limitation, a high resolution active matrix light emitting diode (LED) display, includes a plurality of serially arranged deposition vacuum vessels 4 (e.g., deposition vacuum vessels 4 a - 4 x ). The number and arrangement of deposition vacuum vessels 4 is dependent on the number of deposition events required for any given product to be formed therewith. [0027] In use of shadow mask deposition system 2 , a flexible substrate 6 translates through the serially arranged deposition vacuum vessels 4 by means of a reel-to-reel mechanism that includes a dispensing reel 8 and a take-up reel 10 . [0028] Each deposition vacuum vessel includes a deposition source 12 , a substrate support 14 , a mask alignment system 15 and a compound shadow mask 16 . For example, deposition vacuum vessel 4 a includes deposition source 12 a , substrate support 14 a , mask alignment system 15 a and compound shadow mask 16 a ; deposition vacuum vessel 4 b includes deposition source 12 b , substrate support 14 b , mask alignment system 15 b and compound shadow mask 16 b ; and so forth for any number of deposition vacuum vessels 4 . [0029] Each deposition source 12 is charged with a desired material to be deposited onto substrate 6 through one or more openings in the corresponding compound shadow mask 16 which is held in intimate contact with the portion of substrate 6 in the corresponding deposition vacuum vessel 4 during a deposition event. [0030] Each compound shadow mask 16 of shadow mask deposition system 2 includes one or more openings. The opening(s) in each compound shadow mask 16 corresponds to a desired pattern of material to be deposited on substrate 6 from a corresponding deposition source 12 in a corresponding deposition vacuum vessel 4 as substrate 6 translates through shadow mask deposition system 2 . [0031] Each compound shadow mask 16 is formed of, for example, nickel, chromium, steel, copper, Kovar® or Invar®, and has a thickness desirably between 20 and 200 microns, and more desirably between 20 and 50 microns. Kovar® and Invar® can be obtained from, for example, ESPICorp Inc. of Ashland, Oreg. In the United States, Kovar® is a registered trademark, Registration No. 337,962, currently owned by CRS Holdings, Inc. of Wilmington, Del., and Invar® is a registered trademark, Registration No. 63,970, currently owned by Imphy S.A. Corporation of France. [0032] Those skilled in the art will appreciate that shadow mask deposition system 2 may include additional stages (not shown), such as an anneal stage, a test stage, one or more cleaning stages, a cut and mount stage, and the like, as are well-known. In addition, the number, purpose and arrangement of deposition vacuum vessels 4 can be modified by one of ordinary skill in the art as needed for depositing one or more materials required for a particular application. An exemplary shadow mask deposition system and method of use thereof is disclosed in U.S. patent application Ser. No. 10/255,972, filed Sep. 26, 2002, and entitled “Active Matrix Backplane For Controlling Controlled Elements And Method Of Manufacture Thereof”, which is incorporated herein by reference. [0033] Deposition vacuum vessels 4 can be utilized for depositing materials on substrate 6 to form one or more electronic elements of the electronic device on substrate 6 . Each electronic element may be, for example, a thin film transistor (TFT), a memory element, a capacitor etc., or, a combination of one or more of said elements to form a higher level electronic element, such as, without limitation, a sub-pixel or a pixel of the electronic device. In accordance with the present invention, a multi-layer circuit can be formed solely by successive depositions of materials on substrate 6 via successive deposition events in deposition vacuum vessels 4 . [0034] Each deposition vacuum vessel 4 is connected to a source of vacuum (not shown) which is operative for establishing a suitable vacuum therein in order to enable a charge of the material disposed in the corresponding deposition source 12 to be deposited on substrate 6 in a manner known in the art, e.g., sputtering or vapor phase deposition, through the one or more openings in the corresponding compound shadow mask 16 . [0035] Herein, substrate 6 is described as a continuous flexible sheet which is dispensed from dispensing reel 8 , which is disposed in a pre-load vacuum vessel, into the deposition vacuum vessels 4 . However, this is not to be construed as limiting the invention since shadow mask deposition system 2 can be configured to continuously process a plurality of standalone or individual substrates. Each deposition vacuum vessel 4 can include supports or guides that avoid the sagging of substrate 6 as it advances therethrough. [0036] In operation of shadow mask deposition system 2 , the material disposed in each deposition source 12 is deposited on the portion of substrate 6 in the corresponding deposition vacuum vessel 4 through one or more openings in the corresponding compound shadow mask 16 in the presence of a suitable vacuum as said portion of substrate 6 is advanced through the deposition vacuum vessel 4 , whereupon plural, progressive patterns is formed on substrate 6 . More specifically, substrate 6 has plural portions, each of which is positioned for a predetermined time interval in each deposition vacuum vessel 4 . During this predetermined time interval, material is deposited from the corresponding deposition source 12 onto the portion of substrate 6 that is positioned in the corresponding deposition vacuum vessel 4 . After this predetermined time interval, substrate 6 is step advanced so that the portion of substrate 6 is advanced to the next vacuum vessel in series for additional processing, as applicable. This step advancement continues until each portion of substrate 6 has passed through all deposition vacuum vessels 4 . Thereafter, each portion of substrate 6 exiting the final deposition vacuum vessel 4 in the series is received on take-up reel 10 , which is positioned in a storage vacuum vessel (not shown). Alternatively, each portion of substrate 6 exiting shadow mask deposition system 2 is separated from the remainder of substrate 6 by a cutter (not shown). [0037] With reference to FIG. 2 , an exemplary LED pixel 20 a that can be formed via shadow mask deposition system 2 comprises a 2×2 arrangement of sub-pixels 22 , e.g., sub-pixels 22 a - 22 d . Sub-pixels 22 a , 22 b , 22 c and 22 d can be a red sub-pixel, a first green sub-pixel, a second green sub-pixel and a blue sub-pixel, respectively. Alternatively, sub-pixels 22 a , 22 b , 22 c and 22 d can be a red sub-pixel, a first blue sub-pixel, a second blue sub-pixel and a green sub-pixel, respectively. Since LED pixel 20 a is representative of one of several of identical pixels arranged in any user defined array configuration for forming a complete active matrix LED device, the description of LED pixel 20 a , including the color of each sub-pixel 22 , is not to be construed as limiting the invention. In FIG. 2 , the sub-pixels of adjacent pixels 20 b , 20 c and 20 d are shown for illustration purposes. [0038] Sub-pixels 22 a and 22 b are addressed via a pulse signal applied on a Row A bus and via voltage levels applied on a Column A bus and a Column B bus, respectively. Sub-pixels 22 c and 22 d are addressed via a pulse signal applied on a Row B bus and via voltage levels applied on the Column A and the Column B bus, respectively. In the illustrated embodiment, each sub-pixel 22 includes cascade connected transistors 24 and 26 , such as, without limitation, thin film transistors (TFTs); an LED element 28 formed of light emitting material 30 sandwiched between two electrodes; and a capacitor 32 which serves as a voltage storage element. In an exemplary, non-limiting embodiment, transistors 24 and 26 , LED element 28 and capacitor 32 of each sub-pixel 22 are interconnected to each other in a manner illustrated in FIG. 2 . In addition, for each sub-pixel 22 , a control or gate terminal of transistor 24 is electrically connected to a suitable row bus, a node 34 formed by the connection of the drain terminal of transistor 26 to one terminal of capacitor 32 is connected to a power bus (Vcc), and the source terminal of transistor 24 is connected to a suitable column bus. [0039] To activate each LED element 28 when a suitable voltage is applied to the corresponding power bus Vcc, the voltage applied to the corresponding column bus connected to the source terminal of transistor 24 is changed from a first voltage 40 to a second voltage 42 . During application of second voltage 42 , a pulse signal 44 is applied to the row bus connected to the gate terminal of transistor 24 . Pulse signal 44 causes transistors 24 and 26 to conduct, whereupon, subject to the voltage drop across transistor 26 , the voltage of power bus Vcc is applied to one terminal of LED element 28 . Since the other terminal of LED element 28 is connected to a different potential, e.g., ground potential, the application of the voltage applied to power bus Vcc to LED element 28 causes LED element 28 to illuminate. During application of pulse signal 44 , capacitor 32 charges to the difference between second voltage 42 and the voltage on power bus Vcc, minus any voltage drop across transistor 24 . [0040] Upon termination of pulse signal 44 , capacitor 32 retains the voltage stored thereon and impresses this voltage on the gate terminal of transistor 26 , whereupon LED element 28 is held in an active, illuminating state in the absence of pulse signal 44 . [0041] LED element 28 is turned off when pulse signal 44 is applied in the presence of first voltage 40 on the corresponding column bus. More specifically, applying pulse signal 44 to the gate terminal of transistor 24 when first voltage 40 is applied to the source terminal of transistor 24 causes transistor 24 to turn on, whereupon capacitor 32 discharges through transistor 24 thereby turning off transistor 26 and deactivating LED element 28 . Upon termination of pulse signal 44 , capacitor 34 is charged to approximately voltage 40 , whereupon transistor 26 is held in its off state and LED element 28 is held in its inactive state even after pulse signal 44 is terminated. [0042] In a like manner, each LED element 28 of each sub-pixel 22 of each pixel 20 can be turned on and off in response to the application of a pulse signal 44 on an appropriate row bus when second voltage 42 and first voltage 40 , respectively, are applied to the appropriate column bus in the presence of a suitable voltage applied via the appropriate power bus Vcc. [0043] With reference to FIG. 3 and with continuing reference to FIG. 2 , a sub-pixel structure 50 representative of the physical structure that forms each sub-pixel 22 of each pixel 20 includes, in desired order of deposition, elongated semiconductor segment 52 , elongated semiconductor segment 54 , elongated metal segment(s) 56 , elongated metal segment 58 , elongated metal segment 60 , rectangular metal segment 62 , elongated metal segment(s) 64 , elongated metal segment 66 , elongated insulator segment 68 , rectangular insulator segment 70 , rectangular insulator segment 72 , elongated metal segment(s) 74 , elongated metal segment 76 , rectangular metal segment 78 and rectangular metal segment 80 . [0044] Each metal segment 56 - 66 and 74 - 80 can be formed of any suitable electrically conductive material that is depositable via a shadow mask deposition process, such as, without limitation, molybdenum (Mo), copper (Cu), nickel (Ni), chromium (Cr), aluminum (Al), gold (Au) or indium-tin oxide (ITO). Insulator segments 68 - 72 can be formed of any suitable electrically nonconductive material that is depositable via a shadow mask deposition process, such as, without limitation, aluminum oxide (Al 2 O 3 ) or silicon dioxide (SiO 2 ). Each semiconductor segment 52 and 54 can be formed of a semiconductor material that is depositable via a shadow mask deposition process and which is suitable for forming a thin-film transistor (TFT) by vacuum evaporation, such as, without limitation, cadmium selenide (CdSe), cadmium sulfide (CdS) or tellurium (Te). [0045] In sub-pixel structure 50 , the stack comprised of metal segment 62 , insulator 72 and metal segment 80 forms capacitor 32 ; the combination of the segments forming capacitor 32 along with semiconductor segment 54 and metal segment 60 form transistor 26 (with metal segments 80 , 60 and 62 being the respective gate, source and drain of transistor 26 ); and the combination of semiconductor segment 52 , metal segments 56 and 58 , insulator segment 68 and metal segments 74 and 76 forming transistor 24 (with metal segments 56 and 58 being the source and drain of transistor 24 , and with metal segments 74 and 76 forming the gate of transistor 24 ). [0046] Desirably, each sub-pixel 22 in FIG. 2 is realized by the same sub-pixel structure, such as sub-pixel structure 50 . However, this is not to be construed as limiting the invention since each sub-pixel 22 can be realized by any suitable sub-pixel structure. For purpose of describing the present invention, however, it will be assumed hereinafter that each sub-pixel 22 is realized by sub-pixel structure 50 . [0047] In one exemplary, non-limiting, embodiment, substrate 6 is formed of an electrically insulative material, such as an insulative coated metal sheet; metal segments 60 , 62 and 80 are formed from Mo, Cu, Ni, Cr, Au or Al; insulator segments 68 - 72 are formed from Al 2 0 3 or SiO 2 ; metal segments 56 , 58 , 64 , 66 and 74 - 78 are formed from Mo, Cu, Ni, Cr, Au or Al and semiconductor segments 52 and 54 are formed from CdSe, CdS, Te or any other suitable semiconducting material that can be deposited via a shadow mask deposition process. [0048] To complete formation of each functioning sub-pixel 22 , a suitable insulating material (not shown) is deposited atop of the sub-pixel structure 50 shown in FIG. 3 with an opening exposing all or a portion of metal segment 60 . Another metal segment 36 can then be deposited atop the thus deposited insulating material in contact with metal segment 60 via the opening in the insulating material. Thereafter, light emitting material 30 can be deposited atop the sub-pixel structure 50 in contact with metal segment 36 and a transparent metal segment 38 can be deposited atop light emitting material 30 , whereupon light emitting material 30 is sandwiched between metal segment 36 and transparent metal segment 38 . Desirably, each deposit of metal segment 36 , light emitting material 30 and transparent metal segment 38 is deposited atop of their corresponding sub-pixel 22 in isolation from adjacent deposits of metal segment 36 , light emitting material 30 and transparent metal segment 38 atop their corresponding sub-pixels 22 . Lastly, a layer or sheet of transparent metal (not shown) can be deposited atop of all of the metal layers 38 and the insulating material therebetween as a common electrode for all of the sub-pixels. [0049] With reference to FIG. 4 and with continuing reference to FIGS. 1-3 , a physical implementation of an LED pixel structure corresponding to the circuit schematic of FIG. 2 is shown upon substrate 6 . In one exemplary embodiment, the overall dimensions of each pixel 20 are 126×126 microns and the overall dimensions of each sub-pixel 22 are 63×63 microns. The foregoing dimensions of each pixel 20 and each sub-pixel 22 a , however, are exemplary only and are not to be construed as limiting the invention. [0050] An exemplary, non-limiting sequence of depositions through openings in compound shadow masks 16 of shadow mask deposition system 2 to form the sub-pixel structure 50 comprising each sub-pixel 22 will now be described. [0051] With reference to FIGS. 5A-5C and with continuing reference to all previous figures, each compound shadow mask 16 includes a first shadow mask 90 having a plurality of first apertures 92 therethrough and a second shadow mask 94 having a plurality of second apertures 96 therethrough. The description of first and second shadow masks 90 and 94 having a plurality of first apertures 92 and a plurality of second apertures 96 therethrough, respectively, is not to be construed as limiting the invention since first shadow mask 90 may only include a single first aperture 92 and second shadow mask 94 may only include a single second aperture 96 therethrough if desired. For purpose of describing the present invention, it will be assumed that first shadow mask 90 has a plurality of first apertures 92 therethrough and second shadow mask 94 has a plurality of second apertures 96 therethrough. [0052] Each deposition vacuum vessel 4 desirably includes an instance of the same compound shadow mask 16 . Thus, the compound shadow mask 16 b in deposition vacuum vessel 4 b is desirably the same as the compound shadow mask 16 a in deposition vacuum vessel 4 a ; the compound shadow mask 16 c in deposition vacuum vessel 4 c is desirably the same as the compound shadow mask 16 in deposition vacuum vessel 4 b ; and so forth. More specifically, the first shadow masks 90 forming compound shadow masks 16 are desirably identical, the second shadow masks 94 forming compound shadow masks 16 are desirably identical, and each shadow mask 90 is desirably identical to each shadow mask 94 . Thus, identical shadow masks 90 a and 94 a are desirably utilized to form compound shadow mask 16 a ; identical shadow masks 90 b and 94 b are desirably utilized to form compound shadow mask 16 b , and so forth. [0053] In order to accomplish the desired deposition of materials to form the various segments of each sub-pixel structure 50 , the positions of first and second shadow masks 90 and 94 forming each compound shadow mask 16 are adjusted with respect to each other such that the respective first and second apertures 92 and 96 are positioned at least partially in alignment to define openings 98 of suitable dimensions or sizes and locations in compound shadow mask 16 for the deposition of material therethrough. Each compound shadow mask 16 can also be positioned within the corresponding deposition vacuum vessel 4 in a manner to position openings 98 to facilitate the deposition of the corresponding material at desired locations upon substrate 6 . [0054] It has been observed that in order to deposit each segment 52 - 80 of each sub-pixel structure 50 utilizing identical compound shadow masks 16 formed from identical shadow masks 90 and 94 , that the height and width of each aperture 92 and 96 need be only slightly greater than one-half of the height and width of sub-pixel structure 50 . Thus, for example, if the overall dimensions of sub-pixel structure 50 are 63×63 microns, it is only necessary that the overall dimensions of each aperture 92 and 96 be slightly greater than one-half of the dimensions of sub-pixel structure 50 , e.g., 34×34 microns as shown in FIG. 5A . [0055] Limiting the length and width of each aperture 92 and 96 to slightly more than one-half of the respective length and width of each sub-pixel structure 50 enables the shadow masks 90 and 94 comprising the compound shadow masks 16 of shadow mask deposition system 2 to deposit each segment 52 - 80 of each sub-pixel structure 50 while avoiding undesirable alignment of one or more instances of a single first apertures 92 with two or more second apertures 96 , or vice versa. More specifically, the actual length and width of each aperture 92 and 96 is selected as a compromise between avoiding undesirable overlap of one or more instances of a single first apertures 92 with two or more second apertures 96 , or vice versa, while, as shown best in FIG. 3 , enabling desirable overlapping of deposited segments, e.g., segment 66 overlapping segment(s) 56 ; segment 76 overlapping segment(s) 74 ; segment(s) 64 overlapping segment 66 , and so forth. In other words, limiting the length and width of each aperture 92 and 96 to slightly more than one-half of the length and width of the corresponding sub-pixel structure 50 enables the formation of a densely packed array of sub-pixel structures 50 by way of identical compound shadow masks 16 , each of which is formed from identical shadow masks 90 and 94 . An obvious benefit of utilizing identical shadow masks 90 and 94 to form each compound shadow mask 16 of shadow mask deposition system 2 is the avoidance of the time and cost associated with designing, fabricating and inventorying a unique shadow mask for each deposition vacuum vessel 4 . Another benefit is the interchangeability of shadow masks 90 and 94 to form each compound shadow mask 16 . This is especially beneficial when a new or clean shadow mask 90 or 94 is utilized to replace a worn-out or dirty (material encrusted) shadow mask. [0056] FIGS. 5A-5C illustrate deposits of semiconductor segments 52 on a portion of substrate 6 via openings 98 a formed by the partial alignments of first apertures 92 a and second apertures 96 a of shadow masks 90 a and 94 a , respectively, forming compound shadow mask 16 a which is disposed in deposition vacuum vessel 4 a having deposition source 12 a for depositing the material forming semiconductor segments 52 on substrate 6 . In FIGS. 5B and 5C , substrate 6 , second shadow mask 94 a and first shadow mask 90 a are shown spaced from each other for illustration purposes. However, in practice, shadow mask 90 a is positioned in intimate contact with shadow mask 94 a which is positioned in intimate contact with substrate 6 during deposition of semiconductor segments 52 . Moreover, in FIGS. 5B and 5C , the height of deposition of semiconductor segments 52 is exaggerated for illustration purposes. [0057] The positioning of the first and second shadow masks 90 and 94 of each compound shadow mask 16 of shadow mask deposition system 2 for depositing material segments 54 - 80 will now be further described with reference to the alignment of a single first aperture 92 and a single second aperture 96 of first and second shadow masks 90 and 94 , respectively, forming the corresponding compound shadow mask 16 . In FIGS. 6-19 , the alignment of the single first aperture 92 and the single second aperture 96 to form the opening 98 in the corresponding compound shadow mask 16 is shown adjacent an exemplary sub-pixel structure 50 for illustration purposes. [0058] With reference to FIG. 6 and with continuing reference to all previous figures, following the deposition of each semiconductor segment 52 on the portion of substrate 6 in deposition vacuum vessel 4 a , said portion of substrate 6 is advanced into deposition vacuum vessel 4 b which includes compound shadow mask 16 b . The first and second shadow masks 90 b and 94 b of compound shadow mask 16 b are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 b and a single second aperture 96 b are aligned to form an opening 98 b of compound shadow mask 16 b for the deposition of semiconductor segment 54 with material from deposition source 12 b. [0059] With reference to FIG. 7 and with continuing reference to all previous figures, following the deposition of each semiconductor segment 54 on the portion of substrate 6 in deposition vacuum vessel 4 b , said portion of substrate 6 is advanced into deposition vacuum vessel 4 c which includes compound shadow mask 16 c . The first and second shadow masks 90 c and 94 c of compound shadow mask 16 c are arranged such that, for each sub-pixel structure 50 , a single first aperture 92 c and a single second aperture 96 c are aligned to form an opening 98 c of compound shadow mask 16 c for the deposition of metal segment 56 with material from deposition source 12 c. [0060] With reference to FIG. 8 and with reference to all previous figures, following the deposition of each metal segment 56 on the portion of substrate 6 in deposition vacuum vessel 4 c , said portion of substrate 6 is advanced into deposition vacuum vessel 4 d which includes compound shadow mask 16 d . The first and second shadow masks 90 d and 94 d of compound shadow mask 16 d are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 d and a single second aperture 96 d are aligned to form an opening 98 d of compound shadow mask 16 d for the deposition of metal segment 58 with material from deposition source 12 d. [0061] With reference to FIG. 9 and with continuing reference to all previous figures, following the deposition of each metal segment 58 on the portion of substrate 6 in deposition vacuum vessel 4 d , said portion of substrate 6 is advanced into deposition vacuum vessel 4 e which includes compound shadow mask 16 e . The first and second shadow masks 90 e and 94 e of compound shadow mask 16 e are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 e and a single second aperture 96 e are aligned to form an opening 98 e of compound shadow mask 16 c for the deposition of metal segment 60 with material from deposition source 12 e. [0062] With reference to FIG. 10 and with continuing reference to all previous figures, following the deposition of each metal segment 60 on the portion of substrate 6 in deposition vacuum vessel 4 e , said portion of substrate 6 is advanced into deposition vacuum vessel 4 f which includes compound shadow mask 16 f . The first and second shadow masks 90 f and 94 f of compound shadow mask 16 f are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 f and a single second aperture 96 f are aligned to form an opening 98 f of compound shadow mask 16 f for the deposition of metal segment 62 with material from deposition source 12 f. [0063] With reference to FIG. 11 and continuing reference to all previous figures, following the deposition of each metal segment 62 on the portion of substrate 6 in deposition vacuum vessel 4 f , said portion of substrate 6 is advanced into deposition vacuum vessel 4 g which includes compound shadow mask 16 g . The first and second shadow masks 90 g and 94 g of compound shadow mask 16 g are positioned such that a single first aperture 92 g and a single second aperture 96 g are aligned to form an opening 98 g of compound shadow mask 16 g for the deposition of each metal segment 64 with material from deposition source 12 g. [0064] With reference to FIG. 12 and with continuing reference to all previous figures, following the deposition of each metal segment 64 on the portion of substrate 6 in deposition vacuum vessel 4 g , said portion of substrate 6 is advanced into deposition vacuum vessel 4 h which includes compound shadow mask 16 h . The first and second shadow masks 90 h and 94 h of compound shadow mask 16 h are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 h and a single second aperture 96 h are aligned to form an opening 98 h of compound shadow mask 16 h for the deposition of metal segment 66 with material from deposition source 12 h. [0065] With reference to FIG. 13 and with continuing reference to all previous figures, following the deposition of each metal segment 66 on the portion of substrate 6 in deposition vacuum vessel 4 h , said portion of substrate 6 is advanced into deposition vacuum vessel 4 i which includes compound shadow mask 16 i . The first and second shadow masks 90 i and 94 i of compound shadow mask 16 i are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 i and a single second aperture 96 i are aligned to form an opening 981 of compound shadow mask 16 i for the deposition of insulator segment 68 with material from deposition source 12 i. [0066] With reference to FIG. 14 and with continuing reference to all previous figures, following the deposition of each insulator segment 68 on the portion of substrate 6 in deposition vacuum vessel 4 i , said portion of substrate 6 is advanced into deposition vacuum vessel 4 j which includes compound shadow mask 16 j . The first and second shadow masks 90 j and 94 j of compound shadow mask 16 j are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 j and a single second aperture 96 j are aligned to form an opening 98 j of compound shadow mask 16 j for the deposition of insulator segment 70 with material from deposition source 12 j. [0067] With reference to FIG. 15 and with continuing reference to all previous figures, following the deposition of each insulator segment 70 on the portion of substrate 6 in deposition vacuum vessel 4 j , said portion of substrate 6 is advanced into deposition vacuum vessel 4 k which includes compound shadow mask 16 k . The first and second shadow masks 90 k and 94 k of compound shadow mask 16 k are positioned such that, for each sub-pixel 50 , a single first aperture 92 k and a single second aperture 96 k are aligned to form an opening 98 k of compound shadow mask 16 k for the deposition of insulator segment 72 with material from deposition source 12 k. [0068] With reference to FIG. 16 and with continuing reference to all previous figures, following the deposition of each insulator segment 72 on the portion of substrate 6 in deposition vacuum vessel 4 k , said portion of substrate 6 is advanced into deposition vacuum vessel 4 l which includes compound shadow mask 16 l . The first and second shadow masks 90 l and 94 l of compound shadow mask 16 l are positioned such that a single first aperture 92 l and a single second aperture 96 l are aligned to form an opening 98 l of compound shadow mask 16 l for the deposition of each metal segment 74 with material from deposition source 12 l. [0069] With reference to FIG. 17 and with continuing reference to all previous figures, following the deposition of each metal segment 74 on the portion of substrate 6 in deposition vacuum vessel 4 l , said portion of substrate 6 is advanced into deposition vacuum vessel 4 m which includes compound shadow mask 16 m . The first and second shadow masks 90 m and 94 m of compound shadow masks 16 m are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 m and a single second aperture 96 m are aligned to form an opening 98 m of compound shadow mask 16 m for the deposition of metal segment 76 with material from deposition source 12 m. [0070] With reference to FIG. 18 and with continuing reference to all previous figures, following the deposition of each metal segment 76 on the portion of substrate 6 in deposition vacuum vessel 4 m , said portion of substrate 6 is advanced into deposition vacuum vessel 4 n which includes compound shadow mask 16 n . The first and second shadow masks 90 n and 94 n of compound shadow mask 16 n are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 n and a single second aperture 96 n are aligned to form an opening 98 n of compound shadow mask 16 n for the deposition of metal segment 78 with material from deposition source 12 n. [0071] Lastly, with reference to FIG. 19 and with continuing reference to all previous figures, following the deposition of each metal segment 78 on the portion of substrate 6 in deposition vacuum vessel 4 n , said portion of substrate 6 is advanced into deposition vacuum vessel 4 o which includes compound shadow mask 16 o . The first and second shadow masks 90 o and 94 o of compound shadow mask 16 o are positioned such that, for each sub-pixel structure 50 , a single first aperture 92 o and a single second aperture 96 o are aligned to form an opening 98 o of compound shadow mask 16 o for the deposition of metal segment 80 with material from deposition source 12 o. [0072] The deposition of metal segment 80 on substrate 6 completes the formation of the electronic element defined by sub-pixel structure 50 . Desirably, all of the sub-pixel structures 50 are formed at the same time in the manner discussed above. Thereafter, if desired, additional segments or layers, described above, can be applied to substrate 6 in furtherance of the fabrication of an electronic device, such as an active matrix LED. [0073] In the foregoing description, all of the shadow masks 90 are the same and all of the shadow masks 94 are the same. In addition, each shadow mask 90 is the same as each shadow mask 94 . Limiting the size of each aperture 92 and 96 to a length and width slightly greater than about one-half of the length and width, respectively, of the sub-pixel structure to be formed thereby enables alignment combinations of apertures 92 and 96 to be utilized to form tightly packed structures, such as an array of sub-pixel structures 50 , on substrate 6 while avoiding overlap of a single first aperture 92 with two or more second apertures 96 , or vice versa, during a deposition event. The use of a plurality of identical shadow masks 90 and 94 to form the compound shadow masks 16 of shadow mask deposition system 2 avoids the need to engineer, manufacture and inventory a large number of different shadow masks having openings of different dimensions (or sizes) and/or locations for use in shadow mask deposition system 2 . [0074] Desirably, the mask alignment system 15 of each deposition vacuum vessel 4 is configured to enable the selective x and/or y alignment of one or both of each individual shadow mask 90 and 94 forming the corresponding compound shadow mask 16 from an exterior of the deposition vacuum vessel 4 whereupon the x and/or y dimension(s) of each opening 98 of the compound shadow mask 16 can be adjusted without breaking the vacuum of the deposition vacuum vessel 4 . Thus, if it is determined that one or more dimensions of material deposited through each opening 98 of a compound shadow mask 16 is out of tolerance, mask alignment system 15 can be utilized to adjust said one or more dimensions without breaking the vacuum of the deposition vacuum vessel 4 to bring subsequent depositions of material into tolerance. The capacity provided by each mask alignment system 15 to adjust one or more dimensions of each opening 98 of a compound shadow mask 16 is particularly useful in a continuous in-line shadow mask deposition system to compensate for the buildup of deposited material on or around each opening 98 during a continuous production process thereby avoiding the need to break the vacuum of the deposition vacuum vessel 4 to adjust the dimensions of each opening 98 in response to such buildup. Each mask alignment system 15 is also useful for establishing the dimensions of each opening 98 and the position thereof in the corresponding deposition vacuum vessel 4 prior to the production deposition of material as well as for correcting for any changes in the dimensions of each opening 98 bought about by means other than the buildup of deposited material, e.g., vibration. [0075] In one non-limiting embodiment, mask alignment system 15 comprises micrometers for adjustment of the x and/or y position of each individual shadow mask 90 and 94 forming the corresponding compound shadow mask 16 . However, this is not to be construed as limiting the invention. [0076] The invention has been described with reference to the preferred embodiment. Obvious modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.

4y

FIELD OF THE INVENTION The present invention relates generally to automating data analysis tasks and, more particularly, to analysis tasks that require navigation between dynamic data that has dissimilar structures. BACKGROUND OF THE INVENTION The present invention provides for systems and methods for automatically navigating between dynamic data that has dissimilar structures. The term “dynamic” as used herein refers to frequent change with respect to data, a characteristic that affects the efficiency of navigation techniques. The term “dissimilar structure” as used herein refers to a data structure containing information that is not present in another data structure. Thus, it is said that the first data structure is dissimilar with respect to the second data structure. A problem in the management of distributed systems is described below to illustrate the prior art background. However, it is to be appreciated that the invention has broader applications. Rapid improvements in both hardware and software have dramatically changed the cost structure of information systems. Today, hardware and software account for a small fraction of these costs, typically less than 20 percent (and declining). The remaining costs relate to the management of information systems, such as software distribution, providing help desk support, and managing quality of service (QoS). Decision support is critical to the management of information systems. For example, in software distribution, we need to know: (i) which machines require software upgrades; (ii) what are the constraints on scheduling upgrades; and (iii) the progress of upgrades once installation has begun. In QoS management, decision support detects QoS degradations, identifies resource bottlenecks, and plans hardware and software acquisitions to meet future QoS requirements. Accomplishing these tasks requires a variety of information, such as, for example, QoS measurements, resource measurements (e.g., network utilizations), inventory information, and topology specifications. Collectively, we refer to these information sources as data. Much of this data is dynamic. Indeed, measurement data changes with each collection interval. Further, in large networks, topology and inventory information change frequently due to device failures and changes made by network administrators. We use the term “dataset” to describe a collection of data within the same structure. For example, a dataset might be organized as a relational table that is structured so that each row has the same columns. Here the data is structured into rows such that each row has a value for every column. A dataset contains multiple “data elements” (hereinafter, just elements), which are instances of data structured in the manner prescribed by the dataset (e.g., a row in a relational table). A group of elements within the dataset is called an “element collection.” An element collection is specified by a “collection descriptor” (e.g., SQL where-clause for a relational table or line numbers for a sequential file). A collection descriptor consists of zero or more “constraints” that describe an element collection. A constraint consists of an “attribute” (e.g., a column name in a relational table or a field in a variable-length record), a relational operator (e.g., =, <, >), and a value. Due to the diversity of software tools, administrative requirements, and other factors, data is typically grouped into multiple datasets. Thus, decision support often requires navigating from an element collection in one dataset to one or more element collections in other datasets. We refer to these as the “source element collection,” “source dataset,” “target element collections” and “target datasets,” respectively. With this background, we state one of the problems addressed by the present invention. We are given a source element collection and multiple target datasets. The objective is to find the target element collection that “best matches” the source element collection. By best matches, it is meant that the structure and content of the source element collection is the most similar to that of the target element collection. To illustrate the problem addressed, we describe a scenario in QoS management. Considered is a situation in which end-users experience poor quality of service as quantified by long response times. The objective is to characterize the cause of long response times by: (i) when they occur; (ii) who is affected; (iii) which configuration elements are involved; and (iv) what components of the configuration element account for most of the delays. The analyst starts with a dataset containing end-to-end response times. The dataset is structured into the following columns: shift, hour, subnet, host, user's division, user's department, user name, transaction issued, and response time. The analyst proceeds as follows: Step 1. The analyst isolates the performance problem. This may be done in any conventional manner, such as, for example, is described in R. F. Berry and J. L. Hellerstein, “A Flexible and Scalable Approach to Navigating Measurement Data in Performance Management Applications,” Second IEEE Conference on Systems Management, Toronto, Canada, June, 1996. In the example, isolation determines that poor response times are localized to the element collection described by the constraints: shift=1, hour=8, subnet=9.2.15, division=25, department=MVXD, user=ABC, and transaction=_XX. At this point, the analyst has characterized when the problem occurs, who is affected, and which configuration elements are involved. Step 2. To determine what components of the configuration element account for most of the delays, the analyst must examine one or more other datasets. After some deliberation and investigation by the analyst, the analyst selects a dataset of operating system (OS) measurements that are structured as follows: hour, minute, shift, subnet, division, department, efficiency, waiting time, CPU waits, I/O waits, page waits, and CPU execution times. Step 3. The analyst selects the subset of the OS data that best corresponds to the response time data. Doing so requires dealing with two issues: (i) the source and target datasets are structured somewhat differently in that the first has transaction information (which the second does not), and the second reports time in minutes (which the first does not); and (ii) the second dataset does not have records for user ABC, the user for which a problem was isolated. To resolve the first problem, the analyst decides to use only the information common to both datasets. So, transaction information and minutes are ignored when navigating from the response time data to the OS data. The second problem is resolved by assuming that users within the same department are doing similar kinds of work. Thus, the target element collection is described by the constraints: shift=1, hour=8, subnet=9.2.15, department=MVXD, and user=ABC. Step 4. The analyst uses the OS data to characterize the host component that contributes the most to response time problems. This characterization reveals that paging delays account for a large fraction of end-to-end response times. Steps 1 and 4 employ similar problem isolation logic. Indeed, automation exists for these steps. Unfortunately, in the prior art, steps 2 and 3 are performed manually. As such, these steps impede the automation, accuracy and comprehensiveness of problem isolation. This, in turn, significantly increases management costs. The challenges raised by steps 2 and 3 above are modest if there are a small number of measurement sources. Unfortunately, the number of measurement sources is large and growing. Disimilarities in the structure of datasets typically arise because measurements are specific to the measured entity. Hence, heterogeneous equipment means heterogeneous measurement sources. Heterogeneity includes the different types of devices (e.g., routers versus file servers), different vendors, and different versions of the same product from the same vendor. With rapid changes in information technology, acquisition cycles are now much longer than technology cycles. For example, depreciation times for personal computers are typically 3 to 5 years, but the technology changes every 9 to 12 months. Further, customers typically upgrade hardware and software in an incremental fashion. The combination of these factors means that customers have an increasingly diverse collection of hardware and software. As such, the diversity of measurement sources is rapidly increasing. One proposed way to attempt to avoid the problem of heterogeneous measurement sources is to build a data warehouse that integrates data with dissimilar structure, as described in R. Kimbell, “The Data Warehouse Toolkit,” John Wiley and Sons, 1996. This is accomplished by employing tools that translate data formats and semantics into a common structure. Such an approach works well for fairly static data that is analyzed frequently in that the cost of building and maintaining the data warehouse is amortized over a long time window and a large number of data accesses. However, in systems management applications, the data is dynamic, such as QoS measurements that change every minute. Also, the detailed data used for solving QoS problems is only needed when a problem arises. Thus, the cost of building and maintaining the data warehouse far outweighs the benefits provided. Existing art for navigating between datasets is specific to the manner in which the data is organized, that is, the conceptual model employed. We consider three such conceptual models: relational data (with variations), multidimensional databases (MDDB), and text documents. While other organizations may exist (e.g., graphical structures, such as hyper linked documents), similar issues arise in these organizations as well. Considered first is data organized as relational tables. Here, a dataset is a table, an element is a row in a table, and a collection descriptor is an SQL where-clause. Navigation between datasets is accomplished through SQL queries that use the join operation. A join requires specifying the table to navigate to (e.g., in the from clause of SQL queries) and the join attributes used in the where clause. However, often times situations exist in which neither the table to navigate to nor the choice of join attributes are known. Thus, while it may be useful to employ join operations in an attempt to achieve automated navigation, the join operation itself does not solve the existing problems. Considered next is data organized as MDDB, as described in R. F. Berry and J. L. Hellerstein, “A Flexible and Scalable Approach to Navigating Measurement Data in Performance Management Applications,” Second IEEE Conference on Systems Management, Toronto, Canada, June, 1996. Conceptually, such an organization can be viewed as a layer on top of the relational model. The MDDB structures attributes into dimensions. Within a dimension, attributes may be further structured into a directed acyclic graph (DAG). Here, a dataset is a cube (a MDDB schema along with its base data), an element is a cell within a cube, and a collection descriptor is a where clause that abides by the hierarchical structure imposed by the MDDB. In the example above, there might be dimensions for Time, Configuration Element, Workload and Metric. In the source dataset, the Workload dimension may contain the attributes division, department, user, and transaction, ordered in this manner. Thus, the coordinate for this dimension would be division=25, department=MVXD, user=ABC, and transaction=_XX. Navigation within a multidimensional database is accomplished by drill-down and drill-up operations. Drill-down adds constraints in one or more dimensions such that the attribute of the constraint is at the next lower level in the dimension's DAG. Drill-up is the inverse operation. It removes constraints in one or more dimensions. The attributes of the constraints removed are at the next higher level in the dimension hierarchies. For example, consider the constraints for the Workload dimension: division=25, department=MVXD, user=ABC, and transaction=_XX. Drill-up yields the constraints division=25, department=MVXD, and user=ABC. Navigation between cubes can be accomplished in many ways. One approach is to use SQL queries, as described in R. Kimbell, “The Data Warehouse Toolkit,” John Wiley and Sons, 1996. However, this suffers from the same drawbacks as described above. Another approach to automated navigation between cubes is to employ a drill-through operation. With drill-through, a source cell is associated with one or more target cells. This is either done by specifying an explicit association or by specifying a program that computes the association dynamically. The former is poorly suited to dynamic environments in which new cubes are added and others are deleted or their structure is modified. The latter provides a mechanism for dealing with these dynamics, but in and of itself, providing programmatic control does not solve the problems associated with determining which target data to navigate to. A third way of organizing data is as text documents. Here, the navigation is from keywords (e.g., as specified in an Internet search engine) or whole documents to other documents. This is accomplished by preprocessing the documents to extract keywords (and keyword sequences) to provide an index. Such an approach works well for fairly static data since the index structures are computed infrequently. However, it works poorly for dynamic data. Further, it is known that data structured as comma-separated-values (or other separators) can readily be treated as relationally structured data. This is accomplished by: (a) describing each column in terms of the distribution of its element values, and (b) using a similarity metric to find comparable columns in other datasets. Still further, existing art on federated and multidatabase systems, as described in M. T. Ozsu and P. Valduriez, “Principles of Distributed Database Systems,” Prentice Hall, 1991, as well as schema integration, as described in J. A. Larson, S. B. Navathe, R. Elmasri, “A Theory of Attribute Equivalence in Databases with Application to Schema Integration,” IEEE Transactions on Software Engineering, vol. 15, no. 4, April 1989, teaches how to address problems with heterogeneous names and semantics of columns in relational databases. These approaches allow for performing SQL queries in which the tables referenced in the from clause may have different relational schema. However, these approaches do not teach how to automate the selection of relational tables to use in the from clause, nor do they address how to determine the target element collection that is closest to the source element collection. SUMMARY OF THE INVENTION The present invention provides systems and methods that aid in decision support applications by automatically selecting data relevant to an analysis. This is accomplished by using the structure of the source dataset in combination with the content of the source element collection to identify the closest element collections within one or more target datasets. Particularly, the invention is implemented in a form which includes certain functional components. These components, as will be explained, may be implemented as one or more software modules on one or more computer systems. A first component is referred to as an inter-dataset navigation engine (IDNE). The IDNE is invoked by analysis applications to automate the selection of related data. The IDNE makes use of another component referred to as dataset access services. The dataset access services component knows the accessible datasets and their structures, creates and manipulates collection descriptors, and provides access to elements within a dataset that are specified by a collection descriptor. In one embodiment, automated navigation according to the invention may be accomplished in the following manner. First, the IDNE iterates across all target datasets to do the following: (a) use the structure of the source and target datasets to transform the source collection descriptor into a preliminary collection descriptor for the subset of the target dataset that is closest to the source element collection; (b) construct the final collection descriptor by transforming the preliminary collection descriptor until it specifies a non-null subset of the target dataset; and (c) compute a distance metric representing how close the source element collection (or collection descriptor) is to the target element collection (or collection descriptor). The IDNE then returns a list of triples including a name of the target dataset, a target collection descriptor, and a value of the distance metric for each target dataset. The list may be presented to an end-user who then selects the preferred target dataset. Alternatively, the list may be provided to a program that does additional processing. The list may be sorted by descending value of the distance metric so as to provide a ranking of the target datasets and their target element collections. It is to be appreciated that the systems and methodology of the present invention advantageously eliminate the drawbacks (e.g., accuracy, comprehensiveness, etc.) that exist in the manual navigation approach and other prior art approaches described above. To illustrate the operation of this methodology, we apply it in the context of the previously presented exemplary scenario. Recall that the collection descriptor of the elements in the source dataset is: shift=1, hour=8, subnet=9.2.15, division=25, department=MVXD, user=ABC, and transaction=_XX. We also use the operating system (OS) data previously introduced. This data is structured into the following columns: shift, hour, minute, subnet, division, department, efficiency, waiting time, CPU waits, I/O waits, page waits, and CPU execution times. The invention performs steps (a) through (c) above as follows. A preliminary collection descriptor is constructed for the OS data by transforming the source collection descriptor (step (a)). In particular, the constraints such as transaction=_XX that have an attribute that is not present in the target dataset are addressed. One approach to resolving this is to remove such constraints. Doing so yields: shift=1, hour=8, subnet=9.2.15, division=25, department=MVXD, and user=ABC. Next, the final collection descriptor in the target dataset is constructed (step (b)). This can be achieved by doing the following. First, the element collection specified by the preliminary collection descriptor is retrieved. If this collection is empty, one or more constraints from the collection descriptor are removed. This is repeated until a non-null element collection is obtained. In the exemplary scenario, there is no data for user ABC. So, the constraint user=ABC is removed. Thus, the final target collection descriptor is shift=1, hour=8, subnet=9.2.15, division=25, and department=MVXD. Lastly, the metric for the distance between the source and target element collections is computed (step (c)). Note that in the above construction, the target collection descriptor always has a subset of the constraints in the source collection descriptor. Thus, a convenient distance metric is the difference between the number of constraints in the source and target collection descriptors. In the exemplary scenario, this value is two. Accordingly, the present invention provides automation for selecting datasets relevant to analysis tasks. Such automation is crucial to improving the productivity of decision support in systems management applications. The automation enabled by the invention provides value in many ways. For example, the invention makes the novice analyst more expert by providing a list of target datasets and collection descriptors that are closest to an element collection at hand (i.e., the source element collection). As a result, the novice focuses on the datasets that are most likely to be of interest in the analysis task. By way of further example, the invention makes expert analysis more productive. This is achieved by providing the target collection descriptor for each target dataset thereby enabling the construction of a system in which analysts need only click on a target dataset (or collection descriptor) in order to navigate to its associated element collection. The techniques employed today for dataset selection (e.g., drill-through in MDDBs) embed fixed associations between datasets or require special purpose programs that must be maintained if datasets and/or attributes are added or deleted. In contrast, the invention uses the structure of the data itself to select relevant data. Such an approach adapts automatically to changes in the structure and content of the data being analyzed. In another embodiment of the invention, the set of attributes considered when transforming the source collection descriptor into the target collection descriptor may be constrained. Indeed, the exemplary scenario does not consider the attributes response time, efficiency, waiting time, CPU waits, I/O waits, page waits, and CPU execution time. In yet another embodiment of the invention, different levels of importance may be assigned to attributes. For example, a match on the attribute subnet may be considered more important than a match on the attribute division. This may be implemented by changing the manner in which the distance metric is computed so that it includes weights assigned. In this way, differences in the values of more important attributes result in larger distances than do differences in less important attributes. Automated navigation according to the invention can be applied in many domains. For example, in analysis of manufacturing lines, measurement datasets exist for machines in the manufacturing line as well as for the interconnection of these machines. Automated navigation according to the invention can aid with decision support for scheduling and planning based on this data. By way of a further example, in transportation systems, datasets exist for measurements taken by road sensors and traffic reports. Automated navigation according to the invention can aid in planning highway capacity over the entire network of roadways. It is to be understood that the above applications are merely exemplary in nature and not intended to limit the applicability of the invention. Furthermore, it is to be appreciated that automated navigation according to the invention can be accomplished centrally at a server or in a distributed manner amongst several smaller server machines. These and other objects, features and advantages of the present invention will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a block diagram illustrating a system for implementing an automated navigation system according to an exemplary embodiment of the invention; FIG. 1B is a block diagram illustrating a hardware implementation for both an end-user computer system and an analysis server computer system according to the invention; FIG. 2 is a flow diagram illustrating an automated navigation method according to an exemplary embodiment of the invention; FIG. 3 is a flow diagram illustrating a technique for computing a target collection descriptor that best matches a source collection descriptor according to an exemplary embodiment of the invention; FIG. 4 is a flow diagram illustrating a technique for computing a distance metric according to an exemplary embodiment of the invention; and FIG. 5 is a diagram illustrating a graphical user interface for presenting exemplary results associated with automatic navigation according to an exemplary embodiment of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS It is to be appreciated that the term “processor” as used herein is intended to include any processing device, such as, for example, one that includes a CPU (central processing unit). The term “memory” as used herein is intended to include memory associated with a processor or CPU, such as, for example, RAM, ROM, a fixed memory device (e.g., hard drive), a removable memory device (e.g., diskette), etc. In addition, the term “input/output devices” or “I/O devices” as used herein is intended to include, for example, one or more input devices, e.g., keyboard, for inputting data to the processing unit, and/or one or more output devices, e.g., CRT display and/or printer, for providing results associated with the processing unit. It is also to be understood that various elements associated with a processor may be shared by other processors. Accordingly, software components including instructions or code for performing the methodologies of the invention, as described herein, may be stored in one or more of the associated memory devices (e.g., ROM, fixed or removable memory) and, when ready to be utilized, loaded in part or in whole (e.g., into RAM) and executed by a CPU. Referring to FIG. 1A, a block diagram is shown of a system for implementing an automated navigation system according to an exemplary embodiment of the invention. As shown, an end-user computer system 102 is coupled to one or more analysis server computer systems 104 - 1 through 104 -K. Each analysis server includes one or more analysis applications 110 - 1 through 110 -N with which the end-user computer system interfaces. The analysis applications are analysis programs relating to various applications for which analysis of datasets is required, e.g., manufacturing lines, transportation systems, etc. The analysis applications use a service interface component 120 to access datasets associated with a dataset access service component 130 . The analysis applications also use the service interface component 120 to access the services of an inter-dataset navigation engine (IDNE) 140 . It is to be appreciated that the services interface component 120 is employed as an interface between the analysis applications and the dataset access service component 130 and the IDNE 140 since the various analysis applications may have different communication formats. In this manner, the dataset access service component and the IDNE do not have to handle a large variety of communication formats when communicating with the analysis applications, but rather, they communicate with the services interface 120 which preferably converts the various formats to a single format understood by the dataset access service and IDNE. The services interface component 120 may also serve as a buffer for the dataset access service and the IDNE. The particular implementation of the services interface component is not critical to the invention since, given the design choices for the communication formats of the analysis applications, the dataset access engine and the IDNE, implementation of the interface is a matter of programming choice within the skill level of the ordinary artisan. The IDNE 140 , as will be explained in detail below, provides automation for selecting target element collections that are close to a source element collection. To accomplish this, the IDNE has access to an externally specified description of attribute weights 145 that provides a means to associate a positive value with each attribute of every dataset accessed through a dataset access engine 150 . The IDNE makes use of the dataset access service 130 . Within the dataset access service 130 is the dataset access engine 150 and one or more datasets 160 - 1 through 160 -M. It is to be appreciated that the dataset access engine 150 may be implemented in many ways. For data that is organized as relational tables, engine 150 is implemented as a relational database engine. For data that is organized as a multidimensional database, engine 150 is implemented as a MDDB engine. Further, the dataset access engine 150 may be a combination of several conventionally available data access engines. The engine and its datasets may be local to a single computer or may be distributed across a plurality of computers, e.g., using a client-server protocol. Referring now to FIG. 1B, a block diagram is shown of a hardware implementation for both an end-user computer system 102 and an analysis server computer system (e.g., 104 - 1 through 104 -K) for implementing the invention. Each computer system includes a processor 170 coupled to a memory 180 and I/O device(s) 190 . In the case of an analysis server, the processor 170 performs the functions associated with the various components running therein. The memory 180 is used by the processor for performing such functions and for storing the datasets and results of the processes. The I/O devices may include one or more data input devices (e.g., keyboard, etc.) for inputting data, if needed, and/or one or more data output devices (e.g., display) for presenting a user with results associated with the functions performed in accordance with the various components. For example, a display may present a user with a graphical user interface for viewing such results. As indicated, both the end-user computer system and analysis computer system may have such a hardware architecture. Also, it is to be appreciated that each analysis server may be in communication with the end-user and each other analysis server via conventional communication links, e.g., local area network, wide area network, etc. Further, as mentioned, more than one computer system may be employed to implement the components illustrated in any one analysis server. Referring to FIG. 2, a flow diagram is shown of an automated navigation method according to an exemplary embodiment of the invention. It assumed that a user (e.g.,. analyst) at the end-user computer system 102 calls upon at least one of the analysis application programs ( 110 - 1 through 110 -N) running on at least one of the analysis servers ( 104 - 1 through 104 -K) to assist in a particular analysis task, e.g., the long response time example detailed above. In such, case, the analysis application communicates with the IDNE 140 and dataset access services 130 such that these components can provide the user with automated navigation between datasets containing dynamic data and having dissimilar structures in order to complete the particular analysis task. Accordingly, in step 200 , the IDNE is provided with a source collection descriptor (SCD) from an analysis application. The source collection descriptor may have been identified by the user at the end-user system or generated by the analysis application. Similarly, in step 210 , the IDNE is provided with a list of target datasets (LTDS) from an analysis application. Again, these may also be specified by the user or the analysis application. The IDNE then obtains the listed target datasets from the dataset access engine 150 . It is to be understood that the dataset access engine 150 retrieves these datasets from the appropriate memory locations where such datasets are stored. Then, in step 220 , the IDNE considers each target dataset within this list in turn. TDS denotes a target dataset in the LTDS. In step 230 , a collection descriptor in TDS is obtained such that the collection descriptor is closest to (best matches) the SCD input to the IDNE in step 200 . In step 240 , the IDNE computes the distance (DIST) between the source and target element collections. Then, in step 250 , the name of the target dataset, the target collection descriptor, and the computed distance are saved in an OUTPUTLIST. The method then returns to step 220 where it is determined whether all the target datasets have been processed. If they have not, then steps 230 , 240 and 250 are repeated for each TDS in turn. If all TDSs have been processed, the IDNE proceeds to step 260 . In step 260 , OUTPUTLIST which contains the triplet set of information for each TDS processed is sorted by DIST. That is, each target collection descriptor generated may be ranked in a list with the target collection descriptor resulting in the smallest distance metric with respect to the source collection descriptor appearing at the top of the list and target collection descriptors resulting in increasingly larger distance metrics with respect to the source collection descriptor appearing correspondingly lower in the list. The OUTPUTLIST is then returned by the IDNE to the analysis application, which then provides the list to the end-user 102 for display to the user. Referring now to FIG. 3, an exemplary technique is shown for computing a target collection descriptor that best matches a source collection descriptor, e.g., step 230 of FIG. 2 . In step 310 , a preliminary target collection descriptor (PTCD) is constructed for the current target dataset being considered by appropriately transforming the source collection descriptor. For datasets organized as relational tables, this can be accomplished in the manner specified by the following pseudo-code: pTCD = Default collection descriptor for TDS Do for each constraint in SCD (which is the SQL where clause used in the SCD)  If the attribute of the constraint is in the schema of TDS   add the constraint to pTCD End For datasets organized as multidimensional databases, step 310 may be accomplished in the manner specified by the following pseudo-code: Do for each dimension sd in the source dataset  td = dimension in TDS that's closest to sd  (e.g., most attributes in common)  scv = vector of SCD constraints for dimension sd  tcv = vector of constraints in scv for which the  attributes are in TDS  Set dimension td of pTCD to tcv End In step 320 , the final target collection descriptor is computed. For relationally organized data, this can be accomplished in the manner specified by the following pseudo-code: TCD = pTCD Do until the element collection specified by TCD is empty  For each constraint in TCD   TCD′ = TCD − {constraint}   If the element collection of TCD′ is not empty    TCD = TCD′    Leave the do-loop   Endif  End  Choose a constraint in TCD and delete it End This code removes constraints from the preliminary collection descriptor until a non-empty element collection is obtained. To perform step 320 for data organized into a multidimensional database, the following pseudo-code may be employed: TCD = pTCD Do until the element collection specified by TCD is not empty  For each dimension td in TCD   TCD′ = drill-up of TCD   If the element collection of TCD′ is not empty    TCD = TCD′    Leave the do-loop   Endif  End  TCD = drill-up on all dimensions of TCD End Here, constraints are removed in a manner that preserves the multidimensional structure of the data by performing drill-ups on dimensions until a non-null element collection is obtained. Referring now to FIG. 4, an exemplary technique is shown for computing a distance metric between a source element collection and a target element collection, e.g., step 240 of FIG. 2 . In step 410 , the set of constraints in the source collection descriptor (Count_S) is determined, and the weights of associated attributes (as specified in 145 of FIG. 1A) are added. Similarly, in step 420 , the set of constraints in the target collection descriptor 20 (Count_D) is determined, and the weights of associated attributes (as specified in 145 of FIG. 1A) are added. Then, in step 430 , the difference between the two numbers is computed as the distance metric DIST. Also, it is to be appreciated that the distance metric may alternatively represent a difference in the respective number of constraints in the source collection descriptor and the target collection descriptor. Thus, as mentioned above, constraints may be assigned weights such that a particular constraint is considered more important than another constraint. For instance, if it is determined that constraint A is more important than constraint B, then constraint A is assigned a larger weighting value than constraint B. Then, during respective computations of distance metrics between a source collection descriptor containing constraints A and B and a first target collection descriptor differing only by the absence of constraint A and a second target collection descriptor differing only by the absence of constraint B, the distance metric for the first target collection descriptor will be larger than the distance metric for the second target collection descriptor. This is due to the heavier weighting, that is, greater importance, of constraint A. Therefore, a target collection descriptor that contains constraint A but not constraint B is considered a better match with the source collection descriptor containing constraints A and B than a target collection descriptor that contains constraint B but not constraint A. Referring to FIG. 5, an example is shown of a graphical user interface 500 that displays the results produced by the invention. It is to be appreciated that this is preferably presented to the user (e.g., analyst) on a display associated with the end-user system 102 . The information presented includes the dataset name (e.g., MVS Monitor 3 , UNIX Accounting, Financials, etc.), the target collection descriptor formed for each target dataset considered, and the value of the distance metric computed for each target collection descriptor. Note that the list is sorted in descending order by value of the distance metric. Doing so helps the user to select the target collection descriptor and dataset that are most appropriate for the analysis at hand. Although illustrative embodiments of the present invention have been described herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various other changes and modifications may be affected therein by one skilled in the art without departing from the scope or spirit of the invention.

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BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a process for the separation of plastic particles of a plastic mixture of plastics of a chemically different type which partly have an overlapping and partly a different density range, e.g. polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC). 2. The Prior Art Such different types of plastic occur as waste, for example when different one-way bottles are mixed. For example, still waters are predominantly filled in 1.5-liter PVC-bottles, whereas other beverages are sold in so-called PET-bottles. In Western Europe alone, 1.4 billion PET-bottles are manufactured annually. The bottles have, as a rule, a polyethylene screw cap, whereby the PET-bottles may have a bottom part made of polyethylene as well. Direct recycling of the mixed bottle plastics is not possible because PET melts only at 260° C., whereas PVC decomposes with separation of HCl already above the softening temperature of 160° C. There are, therefore, no appreciable recycling possibilities, so that the waste plastics have not been collected heretofore but eliminated via the household refuse, i.e., they are finally incinerated or deposited. Furthermore, it is not possible, as a rule, to achieve any profits for mixed PVC-containing plastics. The fact is rather that the reuser frequently demands a credit that is oriented on the dumping costs saved. As opposed to the above, there is a market for purely sorted recycling plastics since long, whereby the prices are oriented on the prices for new material. Up to 60% of the new material is achieved for recycling material depending on the quality. Thus there is much interest in processes for the separation of mixed plastics. The processes known from the state of the art for the separation of plastic particles of plastics of a chemically different type operate with plants separating according to the density, for example hydrocyclones. Said process, however, fails in connection with plastics that are in the same density range such as, for example, PET (density about 1.37 to 1.38 g/cm 3 ) and PVC (density about 1.38 g/cm 3 ). However, the separation of polyethylene (PE) from the other two plastic types PET and PVC is possible because of the different density of 0.95 g/cm 3 . The separation of plastics that are in the same density range can be carried out, for example electrostatically. It is known from DE-PS 30 35 649 to separate plastics electrostatically in a free-fall separator. However, it has been found that in the separation of a plastic mixture with three or four different types of plastics, thus for example PE, PET, PS and PVC with one of said processes, a large quantity of medium material is collected, or that the deposits on the respective electrode have only an insufficient degree of purity. Furthermore, the medium material has a high component of at least one of the plastics used. SUMMARY OF THE INVENTION The invention, therefore, has the object of creating a process of the type specified at the beginning in which several components of a plastic mixture even of similar or the same densities can be safely separated from one another. This object is achieved in that the separation takes place in at least two steps, whereby in a first step, the plastic particles having a different density range are separated from each other, and whereby in a second step, the plastic particles with the same density range are separated. In this connection, the plastic particles are advantageously separated in the first step according to the principle of density separation, whereby the density of the separation liquid is selected in such a way that it falls in the field of the greatest density difference between the individual plastic types of the plastic mixture; advantageously, the density of the separation liquid is adjusted in this connection between 1.0 and 1.3 g/cm 3 . The density separation can take place in this connection by means of a hydrocyclone as well. If necessary, the separation according to the density takes place not only in one step but in several ones if several types of plastic with a different density are to be separated. Furthermore, it has been found that it is possible to achieve through a surface treatment of the plastic particles of the plastic mixture an improved triboelectric charging in the sense of a higher charge density. According to an advantageous feature of the invention, the chemical treatment of the surface of the plastic particles of the plastic mixture takes place in that the separation liquid is selected in such a way that it is in the basic range (pH about 10 to 12) or in the acid range (pH of 2 to 4). Particularly advantageous results are obtained if the separation liquid is a salt solution of which NaCl is the main component. In addition to the NaCl in the salt solution, K-, Mg- and SO 4 -ions may be present in the salt solution as well, i.e., because of the desired composition of the salt solution it is possible to use a salt solution as formed as a waste product in the production of potash in potash mining. An enhanced triboelectric charging is particularly achieved also if, after the density separation, the separation liquid is washed out of the plastic mixture by water. In the course of density separation or of the subsequent cleaning of the plastic mixture with water, the plastic particles having a size of under 10 and preferably about under 6 mm can be cleaned from paper residues or beverage residues. However, such cleaning is possible also in a washing process carried out prior to the density separation, for example in a washing mill or in a turbo-washer. After the washing, a drying of the plastic mixture takes place, whereby prior to the actual drying, the water content of the plastic mixture is reduced by a dehydration aggregate, e.g. a centrifuge, to a residual water proportion of under 2%. In the following, the plastic mixture is subjected to a thermal treatment at 30° to 100° C. over a time period of at least 5 minutes; this measure, too, serves for achieving a higher charge density of the individual plastic particles. This is seemingly explainable in that due to the thermal treatment in the aforementioned temperature range, a change occurs in the surface of the plastic particles. The surface treatment can be achieved both chemically and through heat, or through both types of treatment. According to another advantageous feature of the invention, an organic substance, in particular fatty acid is added to the plastic mixture in an amount of about 10 to 50 mg/kg plastic mixture. The addition of fatty acid serves for the conditioning of the plastic particles, also with the objective of obtaining in the subsequent triboelectric charging a higher charge density of the individual particles. This treatment, too, can take place alone or in combination with the chemical or thermal treatment of the plastic particles. It has been found that with plastic particles pretreated in said way, only field intensities of 2 to 3 KV/cm have to be maintained in the free-fall separator itself. As opposed to the above, the free-fall separator operates in connection with the known process with a field intensity of 3 to 4 KV/cm, which posed the danger of spray discharges. Spray discharges may cause an ignition of the plastic mixture in the free-fall separator. The triboelectric charging itself takes place, for example in a fluidized-bed dryer, or in a spiral worm of adequate length, or also by pneumatically conveying the plastic mixture over a certain distance. As marginal conditions it is necessary to maintain in the triboelectric charging temperatures of about 15° to 50° C., preferably 20° to 35° C., and a relative humidity of the ambient air of 10 to 40%, preferably 15 to 20%. The triboelectric charging of the plastic particles themselves takes place in the known way by intimately contacting of the particles with one another. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a flow diagram relating to Example 1; FIG. 2 shows a flow diagram relating to Example 2; and FIG. 3 shows a flow diagram relating to Example 3. The process according to the invention is explained on the basis of the following examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1: Separation of a mixture of beverage bottles is shown in FIG. 1 The mixture of beverage bottles used had the following composition: 76.9% PET 19.8% PVC 2.1% PE 1.2% paper/dirt. The bottle mixture was fed into a wet-operating cutting mill and, under addition of water, crushed to a particle size of under 6 mm. The dirt solution, which also contained paper, was drawn off. Subsequently, the material was vigorously stirred in a washer, which cleaned the surfaces and prepared the latter for the later electrostatic separation. For separating the polyolefins (PE), the substances was admitted into a hydrocyclone. The resulting PVC-PET--mixture was separated from the liquid on a vibration screen, centrifuged, and dried for 6 minutes in a fluidized-bed dryer at 70° to 100° C. In the fluidized bed, any last paper residues that might still be present can be discharged with the exhaust air and separated from the exhaust air by means of a cyclone. The predried material was subsequently contacted in another fluidized-bed dryer for another 3 minutes at 30° C. and at the same time charged. The material draining from the fluidized bed was continuously admitted to a separating plant consisting of two separators. A PET-concentrate with 99.4% PET is obtained already in the preliminary separation; the PVC-concentrate with a PVC-content of 82.3% was conveyed to the after-separation separator by means of a spiral worm, whereby the selective charging of the plastic particles developed. In the after-separation separator, the preconcentrate so charged was separated into a high-percent PVC-concentrate, a medium-material fraction, and a deconcentration fraction containing about 53% PET. The latter together with the medium material of the preseparation was recycled into the fluidized bed for new charging. All in all, it was possible to separate the plastic mixture into a PVC-fraction with a degree of purity of 99.3% PVC, a PET-fraction with a degree of purity of 99.4% PET, and a PE-fraction with a degree of purity of 97.6 PE; the yield (absolute quantity)--based on the bottle mixture used--consisted of: 94.6% PET 96.2% PVC 89.7% PE. EXAMPLE 2: Separation of a PE/PP/PS/PVC plastic mixture is shown in FIG. 2 The used mixture of used plastic articles contained four of the most commonly used mass plastics in the following composition: 45.7% PE 20.1% PP 17.5% PVC 14.9% PS 1.8% residual substances. 100 kg of said mixture was first completely crushed on a cutting mill to a grain size of under 6 mm. The shred mixture was fed into a washer and stirred with fresh water. The washed material was transferred into a flotation basin filled with water, whereas the dirt solution was discarded. The light fraction containing the polyolefins was skimmed off, whereas the heavy fraction containing the PVC and PS was sucked off at the bottom of the basin. Both fractions were predehydrated by means of centrifuging. The PP/PE-fraction was fed into a fluidized-bed dryer and dried for 6 minutes at 80° C. A fatty acid mixture C8-C12 was sprayed onto the draining material in an amount of 50 g/t, and fluidizing was carried out in another fluidized-bed dryer for 3 minutes at 30° C. The mixture flowing from the fluidized bed was continuously fed into a free-fall separator. The medium material of said separation was continuously recycled into the second fluidized-bed dryer. The electrostatic separation of the light fraction supplied the following result: ______________________________________ Analysis Yield Quantity (degree of purity (in % of the kg in %) charge)______________________________________PE-fraction 44.1 96.6 92.2PP-fraction 20.6 88.5 90.7______________________________________ The heavy fraction was transferred into a fluidized-bed dryer with a connected cooler, dried in the heating zone for about 6 minutes at 80° C., and fluidized in the cooling zone for about 3 minutes at 30° C. The electrostatic separation, with recycling of the medium material in this case too, supplied the following result: ______________________________________ Analysis Yield Quantity (degree of purity (in % of the kg in %) charge)______________________________________PVC-fraction 17.3 97.1 95.9PS-fraction 14.8 94.3 93.7______________________________________ EXAMPLE 3: Separation of a PE/PS/PET/PVC-mixture into the individual components is shown in FIG. 3 The used mixture of used plastics had the following composition: 46.8% PE 29.8% PS 12.2% PVC 10.1% PET 1.1% dirt. 100 kg of said mixture was first completely crushed in a cutting mill to a grain size of under 6 mm. The shred mixture was fed into a washer and stirred with fresh water. The washed material was filled in a flotation basin filled with potash waste liquor with a density of 1.2 g/cm 3 . The light fraction containing PE and PS was skimmed off, whereas the heavy fraction containing PVC and PET was sucked off at the bottom of the basin. Both fractions were predehydrated on a swing screen, washed with fresh water, and subsequently predehydrated on centrifuges to an adhering moisture of 2%. The salt-containing waste waters collected in the density separation and predehydration can be recycled into the potash dissolving operation for treatment. Both fractions were fed into separate fluidized-bed dryers equipped in each case with a heating and a cooling zone. In the hot zone, the materials were heated to 80° C., whereby the dwelling time came to about 6 minutes, whereas the cooling zone connected downstream was operated with unheated air. The materials flowing from the fluidized beds were fed into electrostatic free-fall separators, whereby the collected medium materials were recycled into the fluidized beds. The electrostatic separation of the light fraction supplied the following result: ______________________________________ Analysis Yield Quantity (degree of purity (in % of the kg in %) charge)______________________________________PE-fraction 43.8 95.6 93.5PS-fraction 27.7 92.4 92.9______________________________________ The following result was obtained in the electrostatic separation of the heavy fraction: ______________________________________ Analysis Yield Quantity (degree of purity (in % of the kg in %) charge)______________________________________PVC-fraction 12.6 93.9 96.6PET-fraction 9.2 97.1 88.0______________________________________

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RELATED APPLICATION The present application claims benefit of priority from U.S. Provisional Patent Application No. 61/037,125, filed Mar. 17, 2008, and from U.S. Provisional Patent Application No. 61/037,132, filed Mar. 17, 2008, each of which is expressly incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to the field of thermal interface materials (TIMs) for use in electronic devices or other thermal management applications that require rapid dissipation of heat. Examples of devices needing TIMs include computers, telecommunications, space, military, and medical apparatus. 2. Related Art Power dissipation in electronic devices is projected to increase significantly over the next ten years to the range of 100-150 Watts per cm 2 for high performance applications 1 . This increase in power represents a major challenge to systems integration since the maximum device temperature needs to be around 100° C. An additional concern is that leakage currents may also significantly increase as the interconnect size continues to decrease into the nanometer realm. Leakage currents will increase the power dissipation levels well beyond the 150 W/cm 2 range. Thermal management is a major hurdle in the development of faster processors. In a typical chip heat sink assembly, the highest resistance to heat flow comes from the thermal interface material. Typically, the thermal conductivity of a thermal interface material ranges from 1-4 W/mK. One of the ways to increase thermal performance is to improve the thermal conductivity of the thermal interface material. Many concepts have emerged for increasing the thermal conductivity of thermal adhesives and pastes. A widely used approach is to add micron size, highly conductive filler particles in the matrix of the thermal interface material. Another alternative is to use carbon nanotubes. Nanotubes have unique properties as discussed by Iijima 20 and Berber et al. 3 have reported nanotubes have measured high electrical and thermal conductivities (around 6600 W/mK at room temperature) for carbon nanotubes. These can be placed in the thermal interface material to provide a low heat resistance path through the thermal interface material, significantly improving the thermal conductivity of the TIM. See, Doctoral Dissertation of Anand Hasmukh Desai “Thermal Management Of Small Scale Electronic Systems”, Binghamton University, State University of New York, 2006, the entirety of which is expressly incorporated herein by reference. Typical thermal interface materials used in production today include thermal greases and adhesives, thermal gels, phase change materials, and low melt point solders such as Indium 2 . The thermal conductivity for these materials ranges from about 3 (grease and adhesives) to 30 (solders) W/mK. The minimum required thickness of the thermal interface directly impacts the resistance, and varies considerably between these materials. For example, solder TIM solutions need to be considerably thicker than thermal grease due to thermo-mechanical issues. Carbon nanotubes (CNTs) are promising new materials exhibiting extraordinary thermal properties, when grown on a device requiring a thermal interface. Theoretical calculations predict an unusually high value of phonon-dominated thermal conductivity at ca. 6600 W/mK 3,4 , while experimental measurements on individual CNTs confirms a range of 3000-8000 W/(mK) at the room temperature 5,6 . While the exact values and their validation are still under debate, there is little doubt that the extremely high thermal conductivity of CNTs offers the possibility of using CNTs as TIM in electronics packaging to satisfy the increasing power dissipation challenge. SUMMARY AND OBJECTS OF THE INVENTION Challenges in designing a thermal interface material arise due to interfacial resistances, which are a function of surface conditions (devices and heat-sinks or heat spreaders), material properties of the TIM, and the assembly processes used to deposit the TIM and get it to the design point thickness. The interfaces are particularly problematic since they represent a transition between different materials and may contain air voids and other defects. Interfaces typically result in significant thermal resistances. A holistic system level optimization of the heat flow path between the device and the heat sink or heat spreader is desirable. The system level design should account for the thermal, mechanical and chemical properties of the TIM material, the mating surfaces and the effects of the assembly processes. Prior concepts of using CNTs involve growing CNTs directly on a device to be cooled. This method tends to be cost-prohibitive. Thermal interface materials are particularly vulnerable to damage under some application conditions because they may interface between materials with significantly different thermo mechanical properties such as coefficient of thermal expansion and modulus of elasticity. These differences in properties mean that during thermal cycles such as those that arise when a machine is turned on and off, the TIM is subjected to a mechanical load. In many applications, such cycles occur for thousands of times during the life of the product. The thermal interface material must be able to withstand such cycling without sustaining any significant damage. Another issue to be addressed is the impact of the thermal interface material on overall system cost. While the cost of the interface material may be small, if it requires special assembly or handling processes that may slow down the overall assembly process then that may significantly impact the overall system cost. Recent studies on both randomly filled CNT composites 7-9 and vertically aligned CNT (VACNT) arrays 10-12 have shown less than ideal characteristics. Typically, at most a few folds increase in thermal conductivity from that of the base materials has been observed. A problem has been the low conductance at filler/matrix and TIM/solids interfaces. Additional issues in the use of CNTs as TIM's include: Aligning the CNTs or other nano-scale fibers in the direction of transport. In the case of a microprocessor, for example, alignment is preferably perpendicular or near perpendicular to the microprocessor surface, so that the CNT's transport heat to the next level, namely a heat spreader or a heat sink; Attachment between two surfaces to achieve heat transport between those surfaces, such that interfacial resistances between the CNT and the surfaces are acceptably small; Attachment between the two surfaces, so as to allow relative movement between those surfaces—in order to absorb thermo mechanical displacements arising from either CTE differences or temperature differences; or any other mechanical movement that may arise in the application conditions; Location of the active (thermally) CNT at hot spots on the device; Low cost and high volume production, e.g. making the TIM independently manufacturable from the device and the heat spreader; Capable of being readily assembled by a reasonably standard assembly process; Robust and durable components that are not easily damaged during shipping, handling and assembly: This particularly applies to any thermal interface material that contains unprotected delicate structures such as nano- or micro-structures that are subject to damage; and Assembly processes that are reasonably manufacturable at an acceptable cost. It would be desirable to create a new TIM that addresses some or all of the problems listed above. It is especially desirable to manufacture a material in accordance with a method that includes stabilizing nano-scale fibers—prior to applying them to a device requiring a TIM—with a stabilizing material to create a stabilized fiber assembly. The stabilizing material may be a filler disposed amongst the nano-scale fibers. The stabilizing material may be a capping layer added to the fibers. There may be both stabilizing material and at least one capping layer. There may be two capping layers, creating a sandwich-like composite system. Each capping layer may be made of two (or more) sub-layers. Advantageously, the capping material may be a nano- or micro-particle paste that achieves the goals above of attaching the TIM, aligning the nano-scale fibers, and improving thermal conduction. The particles, in turn may be isotropic or anisotropic, and in the case of anisotropic particles, may be anisotropically aligned. Advantageously, the paste may be located adjacent to thermal hotspots in the material to be cooled, while voids in the paste, to improve processing, may be selectively located adjacent spots not expected to get so hot. Thus, for example, voids in the TIM may be statistically difficult to avoid, but may be selectively disposed in areas where they are tolerated. In some cases, a void may be desired, for example to help maintain a spatially uniform device temperature in spite of regionally varying heat dissipation. The material thus manufactured is also advantageous—along with various embodiments and methods of manufacture. Other materials that might be used, analogously to CNTs, include silver or copper nanowires, carbon columns, and any fiber of a highly thermally conductive metal alloy. It is also desirable for devices to be manufactured by adding the TIM after it is first assembled separately from the device requiring the thermal interface. It is an object of the invention to provide a method of manufacturing a thermal interface material, comprising providing a sheet comprising nano-scale fibers, the sheet having at least one exposed surface; and stabilizing the fibers with a stabilizing material disposed in at least a portion of a void space between the fibers in the sheet. The detached sheet having stabilized fibers may be disposed between two layers of an assembly and is adapted to serve as a thermal interface material. The detached sheet having stabilized fibers may be compressed between the two layers of the assembly and heated. The fibers may be anisotropically aligned. The fibers may have axes which are selectively aligned in the direction of required thermal transport. The fibers may have axes which are substantially aligned normal to a plane of the sheet. The method may further comprise depositing a film on a surface of the sheet and/or removing a surface portion of the stabilizing material to expose an end portion of the fibers. For example, the method may comprise applying first and second nano- or micro-particle containing films on respective opposite surfaces of the sheet so that the stabilized fibers are sandwiched between the first and second films and/or applying a first and second nano- or micro-particle containing sub-film on a respective surface of the sheet. A sub-film adjacent to the fibers may comprise palladium. The method may further comprise etching the stabilizing material on at least one surface to create at least one etched portion; and applying at least one respective metallic nano- or micro-particle film to at least one etched portion. The nano- or micro-particle film may comprise sinterable metallic particles coated with at least one sacrificial organic material as a shell; the method further comprising heating the film to disrupt the shell, and sintering the particles to form a substantially contiguous matrix. A pattern of the particle film may be selectively established, in which a first portion of the etched sheet is covered with the particle film and a second portion of the sheet is not covered with the particle film, the pattern being adapted to fill at least one expected gap between the thermal interface material and at least one solid surface. The sheet may be selectively stabilized by differentially providing stabilizing material in different spatial portions of the sheet, and wherein a portion of the sheet with reduced stabilizing material is permeable to gasses. The process for stabilizing may comprise infiltrating the fibers with polymerizable matrix material mixed with nano- or micro-particles; and polymerizing the polymerizable matrix material. The stabilizing process may also comprise compressing the nano-scale fibers along at least one axis to selectively provide an oriented state in which the fibers are selectively oriented along at least one elongation axis; and adding at least one capping layer to retain the fibers in the oriented state. The stabilizing material may be provided with a pattern of regularly distributed voids. The stabilizing material may be selectively disposed on the sheet by a process comprising inkjet printing of polymerizable material and/or deposition of an aerosol of polymerizable material droplets. The stabilizing material may comprise micro or nanoparticles. The stabilizing process may comprise subjecting the sheet to a vacuum; infiltrating the sheet with a polymerizable material; and releasing the vacuum, to thereby push shrink at least a portion of residual void spaces in the polymerizable material. It is a further object to provide a method of manufacturing a device, comprising a) providing a thermal interface material comprising: i) a plurality of aligned nano-scale fibers grown separately from the device forming a sheet; and ii) at least one stabilizing material for stabilizing the fibers in a substantially aligned orientation parallel to a desired direction of heat transfer; and b) forming a thermally conductive interface between the thermal interface material and the device. The thermal interface material may comprise at least one capping layer at a surface of the sheet, and the forming comprises causing the capping layer to conform to a shape of the device. The capping layer may comprise palladium. The fibers may comprise carbon nanotubes. Prior to forming, the ends of the substantially aligned nano-fibers on a surface of the sheet may be selectively exposed. The exposing may comprise selectively removing a portion of the stabilizing material on a surface of the sheet without degrading the ends of fibers within the removed portion of the stabilizing material. The stabilizing material may be removed by an ablation process. The capping layer may also be a solder, e.g., a metallic or metalloid material that melts at a temperature below 450 C, and which, when melted, wets another metal surface to form a bond when cooled. Solders are typically metal alloys, often containing tin, copper, zinc, silver, bismuth, indium, antimony and lead as components. The solder may be provided as a plating, sinterable powder, or dip, and the solder may be provided on the surface to be soldered to the TIM. In some cases, a solder composition may be provided on each side of the TIM, and the solder composition may be the same or different on each, based, for example, on the respective melting points, and materials to be joined. In the case of an excess of solder, the TIM may be formed to provide flow channels to permit, under compression and heat, the excess solder to be removed from the interface. Preferably, these flow channels are disposed in areas with reduced need for heat transfer. The compression during heating permits the fibers extending from a surface of the TIM to pierce the solder, and make direct contact with the surface to be thermally interfaced. The solder, in turn, forms a bond with the TIM, holding it in position and conforming to the mating surface, and provides at least a modest degree of thermal transfer. It is another object to provide a thermal interface material sheet, comprising a layer comprising anisotropically oriented thermally conductive nano-scale fibers, the sheet having at least one exposed surface; a stabilizing material disposed in at least a portion of a void space between the fibers in the layer; and a capping layer in direct contact with an end portion of the fibers proximate to an exposed surface of the sheet, the fibers extending beyond the stabilizing material and into the capping layer. The fibers may comprise carbon nanotubes, the stabilizing material may comprise an organic polymer, and the capping layer may comprise palladium. Another object provides a thermal interface material comprising a plurality of nano-scale fibers having an anisotropic orientation, forming a self-supporting sheet; and a stabilizing material for retaining the fibers in their anisotropic orientation within the self-supporting sheet. The fibers may comprise carbon nanotubes, carbon columns, silver nanowires, copper nanowires, and/or a high thermal conductivity metal alloy. The sheet may have first and second surfaces, each nano-scale fiber having respective first and second ends, the fibers being oriented such that a substantial fraction of the fibers have their respective first ends at the first surface and their second ends at the second surface, so that the fibers directly conduct heat between the first and second surfaces. At least one capping layer may be provided having a direct thermal interface with at least one of the first ends and the second ends of the fibers. The stabilizing material may comprise a filler between the fibers. The stabilizing material may comprise a polymer, formed from a polymerizable material, such as a monomer, prepolymer, resin, or the like. The stabilizing material may comprise a polymerizable material and a concentration of nanoparticles of 20-60% by volume. The stabilizing material may comprise metallic micro- or nano-particles. The stabilizing material may comprise nano- or micro-particles having a thermal conductivity greater than a bulk material of the stabilizing material. The material may further comprise at least one capping layer disposed on a surface of the sheet, at least a portion of the fibers terminating within the capping layer. The capping layer may comprise metallic microparticles which are at least 1 micron in size The thermal interface material may be adapted to reduce mechanical stresses that arise between devices coupled by the thermal interface material as compared to a direct bonding of surfaces of the devices. The thermal interface material may also be adapted to reduce a stress between devices cause by at least one of differences in coefficient of thermal expansion, or differences in temperature. The material as provided may comprise areas having low modulus of elasticity, whereby stresses in an assembly composed of a device, a heat sink, and the thermal interface material disposed between respective surfaces of the device and the heat sink, are reduced. The material may be provided in conjunction with a device or between a pair of devices, each having a surface, wherein the material is selectively bonded to one or both surfaces to provide bonded portions and unbounded portions. The material may be provided such that the stabilization material has a lower modulus of elasticity than the fibers; and at least one of fibers and stabilization material are configured to be selectively disposed at defined hot spots on a device to be cooled, with at least some gaps elsewhere, whereby stresses are reduced. It is another object to provide a method of forming a thermal interface material comprising a plurality of nano-scale fibers having an anisotropic orientation, forming a self-supporting sheet, and a stabilizing material for retaining the fibers in their anisotropic orientation within the self-supporting sheet, comprising the steps of providing a mat of nano-scale fibers; applying a stabilizing material precursor to the mat; subjecting the mat and stabilizing material to temperature and pressure conditions sufficient to produce the stabilizing material and the sheet; removing a portion of the stabilizing material on at least one surface of the sheet while preserving protruding free ends of the nano-scale fibers; and capping the free ends of the nano-scale fibers to provide a direct thermal interface therewith. The sheet is preferably placed between two surfaces, to thereby conduct heat therebetween. Further objects, advantages, and embodiments will be apparent in the following. BRIEF DESCRIPTION OF THE FIGURES The invention will now be described with reference to the following figures, which constitute non-limiting examples: FIG. 1A is a schematic of a TIM in accordance with the invention; FIG. 1B is a side view of the TIM of FIG. 1A ; FIG. 1C is a top view of the TIM of FIG. 1A ; FIG. 1D shows an alternative embodiment to FIG. 1A , with four capping layers; FIG. 1E is an alternative embodiment of FIG. 1B ; FIG. 2 shows assembly of a device in accordance with the invention; FIG. 3 shows VACNT fibers; FIG. 4 shows a TIM in accordance with the invention sintered between two device surfaces; FIG. 5A shows CNT's aligned along a neutral axis responsive to shear from compression; FIG. 5B shows cutting CNT's perpendicular to the neutral axis; and FIG. 6 shows a device incorporating a TIM in accordance with the invention. FIG. 7 shows a schematic diagram of a periodic element used in models of the TIM. FIG. 8 shows an SEM image (Inverted side view) of vertically aligned carbon nanotubes (CNT) at 1,800× magnification, wherein the average height of the tubes is around 25 microns. FIG. 9 shows an SEM image of vertically aligned carbon nanotubes at 40,500× magnification, wherein the diameter of the tube that is measured here is 100 nm. FIG. 10 shows a plot of nanotube elements modeled with random normal distribution length variation and with infinite thermal resistance in the interface (K gap =0.001 W/mK), showing the distribution thermal conductivity convergence. FIG. 11 shows a graph of the ratio of effective thermal conductivity to the bulk conductivity plotted against the percentage of area occupied by the nanotubes on the silicon surface for the normal distribution case with finite resistance case. FIG. 12 shows a graph of the ratio of effective thermal conductivity to the bulk conductivity plotted against the percentage of area occupied by the nanotubes on the silicon surface for the normal distribution infinite resistance case. FIG. 13 shows a graph of the ratio of effective thermal conductivity to the bulk conductivity plotted against the percentage of area occupied by the nanotubes on the silicon surface for the uniform distribution finite case. FIG. 14 shows a graph of the ratio of effective thermal conductivity to the bulk conductivity plotted against the percentage of area occupied by the nanotubes on the silicon surface for the uniform distribution infinite case. FIG. 15 shows a plot of the average value of the ratio of effective thermal conductivity to the bulk conductivity against the percentage of area occupied by the nanotubes on the silicon surface for all the four statistical models. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS For the purposes of this application the terms “nanometer realm” or “nano-scale” are understood to mean approximately 1-100 nm, and preferably 1-10 nm. “Nano-particles” will be in this same size range. Micro range will be understood to mean 0.1 to about 10 microns. FIG. 1A is a schematic diagram of a TIM system in accordance with the invention. FIG. 1A illustrates nano-scale fibers 101 , such as CNT's stabilized in a matrix 102 and sandwiched between two capping layers 103 , such as silver nanoparticle paste. The fibers 101 may be vertically aligned or randomly oriented. There will be some expense associated with getting the fibers to be aligned, but aligned fibers are expected to demonstrate superior performance, and are therefore preferred. On the other hand, even in an unaligned state, a portion of the fibers 101 will be oriented normal to the interface plane. The matrix 102 may include organic or organic/inorganic hybrid material stabilizing the arrays or networks of nano-scale fibers 101 . The fibers 101 function as heat-passages for heat flux. Other materials that might be used as fibers 101 , analogously to CNTs, include silver or copper nanowires, carbon columns, and any other highly thermally conductive fiber, for example formed of metal alloys or organic or mineral materials. To achieve high bulk thermal conductivity, the fibers 101 preferably physically connect the two opposing solid surfaces 401 (shown in FIG. 4 ). Any low conducting interfaces could be detrimental to overall performance. This preference for physical connection holds true no matter whether the fillers in use contain nanoparticles (NPs) or microparticles, or whether the fibers are nanowires (NWs), or nanotubes. Examples of thermal properties of nanowires are discussed in several papers 13,14 . However, at the interfaces between the TIM and solids (such as a die or a heat sink), direct contacts between the nano-scale fibers and solids direct connection is desirable but generally impossible to realize, except perhaps if the fibers are grown between the surfaces, in which case the density of fibers may be too low. Therefore, an approximation of physical contact, which achieves thermal performance approaching that of true physical contact, is preferred. A deformable buffer layer 103 with good interfacial adhesion with both fibers 101 and the solid surface 401 (shown in FIG. 4 ) is therefore provided. Fibers 101 are embedded between capping layers 103 . The capping layers 103 wet the solid surfaces, potentially eliminating voids due to surface roughness. The capping layers 103 also may serve to improve mechanical strength of the TIM, making it more suitable for automatic processing, including being punched out and/or being picked up, carried, or placed, during device assembly. The capping layers 103 may also further serve a lateral heat dissipation function, perpendicular to the direction of heat transport provided by the fibers 101 . The matrix 102 may be, for example, a polymer with included nano- or micro-particles. The assembly shown in FIG. 1A will generally have a thickness in the range of 2 to 1000 microns, preferably in the 100 to 150 micron range. FIGS. 1B and 1E are schematics of a side view. In the embodiment of FIG. 1B , the capping layers 104 are patterned. In the embodiment of FIG. 1E , both the matrix 102 and the capping layers 103 are patterned. By judiciously placing voids 104 in the capping layers 103 , or a different matrix material occupying these zones, both the mechanical characteristics and the processability could be improved. In general, the nanoparticle paste which preferably forms the capping layers 103 is expected to improve thermal conductivity. Therefore paste should be in contact with anticipated hot spots in the circuitry, while voids 104 should be placed where the circuitry needs less cooling. FIG. 1C shows a top view of the TIM of FIGS. 1 a and 1 b , also showing capping layer 103 patterning and voids 104 . FIGS. 1A , 1 B and 1 C illustrate a sandwich-like TIM with nano-scale fibers 101 between two capping layers 103 formed of paste. More layers of paste might be used. For instance, the first thin layer 105 would be applied to the fibers to promote the adhesion of the second layer 106 to the opposing surfaces as illustrated in FIG. 1D . This figure shows the fibers 101 , the polymer matrix 102 , a first capping layer 105 and a second capping layer 106 . Preferably the first, thinner capping layer 105 is formed of palladium deposited from spattering or wax processing of nanoparticles or microparticles or other items in a paste that will go away during processing. There may be a modifier to make the palladium soluble in an appropriate solution. Several different methods of synthesizing nano-scale fibers exist. In particular, with reference to CNTs, there are bulk randomly oriented CNTs, random CNTs in a thin mat, and vertically aligned CNTs (VACNT) on substrates. Those cover a broad TIM performance range while retaining high performance/cost ratios. Because processes such as chemical purification and mechanical mixing break CNTs and introduce defects, preferably the skilled artisan will chose as high a quality CNTs as are currently available and practicable in terms of cost and meet the functional requirements. A number of papers describe methods for synthesizing aligned CNT 15,16 . Randomly oriented clean and long CNTs may be synthesized in large quantities using chemical vapor deposition (CVD). The density of as-synthesized CNT powders can be as low as 30 mg/cm 3 , which can be tuned to optimize the eventual density in composites and the convenient incorporation of matrix materials. Random CNT mats may be obtained through known methods 17 . In addition to the quality of CNTs, density and thickness are characteristics of CNT mats. Synthesis conditions generally control the density CNT mat and thickness, which is generally achievable in the range of tens of microns. High density VACNTs of controlled thickness at the vicinity of 10 microns may also be synthesized. Stabilization: Fibers, such as CNT networks or arrays, can be stabilized by infiltrating the fibers with a filler, such as monomers or mixture of monomers and nanoparticles (NPs) or microparticles followed by polymerization. Preferably, the fibers are placed in an evacuated chamber to allow entry of the monomers, which otherwise do not easily wet the fibers. The chamber is then ventilated to push the monomers further into the fibers. Voids around fibers are then filled with polymer. This polymer then leaves fiber configuration intact, whether it is an entangled network or aligned tubes. Alternatively, monomers may be pushed in by filtration. In the latter case, NPs loaded in monomers are retained in fibers and accumulated to high concentrations. High concentration means 20-60% by volume. High volume fraction of metallic nano- or micro-particles in the matrix allows for formation of interconnected thermal passages upon NP fusing. The monomers are then polymerized. Hence, the thermal conductivity of the matrix is enhanced greatly. The better thermal conductivity is due to the network passages which form upon the fusion of high concentration nano- or micro-particles. Polymerization of monomers provides mechanical integrity of the structures. Fracture surface morphology of a VACNT composite in accordance with the present process is shown in FIG. 3 , showing that the process does not destroy the ordering. Embedded CNTs remain well-aligned. Thus stabilizing the fibers, separate from the device requiring a thermal interface, rather than growing the fibers on the device, allows for more flexibility and lower cost of manufacturing. For example, the fiber mats may be grown under uniform, optimized and tightly controlled conditions, which may be unavailable when seeking to grow the fibers on the device itself. Orientation of CNTs in polymer composites may also be introduced to initially randomly-oriented CNT/polymer composite 9,10,18,19 . In this approach, composites using bulk CNT powders are compressed biaxially followed by curing and polymerization. Biaxial confinement deforms CNT networks, orienting CNTs along the third, or the neutral axis. With deformed CNTs fixed by NP fusion and monomer polymerization, composite films obtained by cutting perpendicular to the neutral axis contain aligned CNTs, resembling the morphology of a composite film prepared using VACNTs. FIG. 5A shows CNTs aligned along a neutral axis responsive to shear from compression. FIG. 5B shows cutting CNT's perpendicular to the neutral axis. Preferably such compression and cutting will be performed prior to application of the capping layer or layers. The CNT may be cut or patterned, for example with a die, laser, water jet, chemical process, optical process, ablative electrical current, or other known cutting tool or mechanism. Indeed, the matrix 102 may be selectively processed after polymerization, to weaken it, and thus permitting a separation. If CNT mats are used, it is possible to fabricate TIMs with the patterned matrix and leave regularly arranged voids in composite films. Inkjet printing or aerosol deposition may be used to deliver monomers (with or without NPs or microparticles) to targeted locations. A known machine for aerosol deposition is the Optomec M3D printer. Patterning per FIG. 1B is particularly desirable to address the issue of local hot spots, where rapid dissipation in directions both perpendicular and parallel to die surface is required. Patterning is a matter of design optimization, a balance of performance vs. cost. Patterning could reduce the cost while still get work done, i.e. dissipating heat from a hot spot. For example, use of precious metals used in the capping layers are may be minimized. Likewise, by reducing the contact area and providing intentional voids, more even contact between the opposed surfaces at the TIM locations may be assured after compressing the TIM between them. Analogous stabilization can be provided for other nano-scale fibers. Capping Layer Deposition: After stabilization with the filler, composite films may be etched using plasma or reactive ions in order to expose the ends of CNTs or other nano-scale fibers at both surfaces of the film. Therefore, it is preferred that the exposing step does not substantially degrade the fibers. NP (such as Ag) films of a few microns thick are coated to both surfaces of the fiber composite film. Individual NPs are coated with wax-like organic shells, hence NP films are readily deformable under pressure. Seamless joints form between the TIM buffer layers and the solid surfaces after they are pressed between two solid surfaces at 100° C. A heat treatment at about 100° C. drives away the waxy organic molecules in the NP shell, triggering the fusion of NPs to form a contiguous metallic layer. This NP layer may therefore be sintered. This layer may also conform to the roughness features of the solid surfaces, connecting CNTs or other nano-scale fibers from one solid surface to the other with high thermal conductivity passages, especially when formed in situ between the opposed surfaces to be connected by the TIM. A substantial fraction of the fibers are preferably oriented so that their ends are at the surfaces to achieve thermal conductivity. Preferably substantially all of the fibers are so oriented, though as discussed above, the alignment requirement varies in dependence on the application and design criteria. Alternatively, microparticles may be used. While using both filler and capping layers is expected to enhance mechanical strength and thermal properties—using one or more capping layers alone, without filler between the fibers, may provide an adequate TIM. Also, the fibers stabilized with filler, and without capping layers, may also provide an adequate TIM. It is further noted that the process may be asymmetric, with the process according to embodiments of the invention provided for only one face of the TIM, with other processes used to interface the other face of the TIM with a respective surface. Using printing (electrostatic, electrophoretic, ink jet, impact) or lithography techniques, capping layers with carefully designed patterns (such as lines, grids, or pads) may be deposited. A design criterion is to deliver just the right amount of materials to fill the gap between TIM and solid surfaces and create seamless contact. FIG. 2 shows a portion of the assembly process of a TIM in accordance with an aspect of the invention. In this figure, a conveyor 201 carries fiber composites 202 past an ink jet printer 203 , which deposits the nano-particle paste on the fiber composites to form patterns such as shown in FIGS. 1B and 1C . There are several advantages of fabricating patterned TIM films. The voids in the matrix layer serve as breathing channels that release the trapped air during assembly, and organic molecules during curing NPs capping layers; the voids accommodate thermal expansion cycles and therefore improve mechanical performance and longevity; and the voids also make films more compressible, facilitate the flow of the NP paste to form better contacts, and reduce the packaging pressure. Once the TIM is completed, it will preferably be added to a device. Adding the TIM to a device will involve temperature and pressure sufficient to remove excessive (and unintended) voids in the material. FIG. 4 shows how sintered metal paste 402 helps the TIM bond with device surfaces 401 . Sandwiched between the capping layers 405 are the nano-scale fibers 403 . Each fiber has a first and second end. Substantially all of the fibers 403 are preferably oriented so that their first end is at a first device surface and their second end is at a second device surface. The fibers 403 are stabilized with a filler 404 , while the sintered metal paste 402 serves as the capping layers. The paste has voids 406 which give flexibility and improved stress reduction. The paste 402 is preferably located at anticipated hot spots on at least one of the device surfaces 401 . FIG. 6 shows a device incorporating a TIM in accordance with the invention. At the top is an air-cooled heat sink 601 . Below that is a layer 609 of TIM (TIM 2 ) in accordance with the invention. Below that is a lid 602 , which functions as a heat spreader. Below that is another layer 610 of TIM in accordance with the invention (TIM 1 ). Below that is the chip 608 . Below that is a layer of first level interconnect C4 bumps 603 , also known as flip chip solder bumps, where C4 is the acronym for Controlled Collapse Chip Connection. The bumps 603 are interspersed with underfill 607 . The bumps 603 and the underfill 607 rest on a substrate 604 . The substrate is connected to the Printed Circuit Board (PCB) 606 via a second level interconnect 605 , similar to elements 603 and 607 . A TIM in accordance with the invention is a hybrid materials system. Preferably this system will include various forms of nanomaterials. This TIM will preferably realize one or more of the following goals: Low temperature application of the TIM, i.e. below 200° C., comparable to the temperature of operation of the device and/or it electrical assembly, to reduce thermal stress during operation; Minimizing thermal resistance between two solid surfaces, Usefulness for any applications requiring very high thermal dissipation by joining two solid surfaces, High bulk thermal conductivity close to theoretical limit of a composite containing CNTs, Readily deformable surfaces to form intimate contacts with solid surfaces of varying topological and roughness features, Variable thickness that can be minimized to a few microns, Mechanical robustness for easy processing and application of TIM as well as long term stability for thermal cycling, and chemical stability therefore environmental and manufacturing friendliness. Individual features could be adjusted to optimize the overall performance of the TIM system. In addition to heat transport, a TIM should reduce or minimize stresses that arise between the devices coupled by the TIM. These stresses may be thermo-mechanical in the sense that they are caused by differences in coefficients of thermal expansion between device areas. Stresses may also be caused by differences in temperatures in different regions of the devices to be coupled. Polymers used in this TIM are preferably chosen to have a low modulus of elasticity. Also, when the TIM is applied, some areas may be unattached to the devices to be coupled to reduce stresses. Similarly there may be voids in the fibers, filler, or capping materials to reduce stresses. During application to a device, a TIM in accordance with the invention may be further processed to expose the ends of the nano-particles immediately prior to application to a device requiring a thermal interface. Such further processing might include mechanical means, chemical means, or laser ablation. From reading the present disclosure, other modifications will be apparent to persons skilled in the art. Such modifications may involve other features which are already known in the design, manufacture and use of thermal insulating materials and nano-scale fibers and which may be used instead of or in addition to features already described herein. Although claims have been formulated in this application to particular combinations of features, it should be understood that the scope of the disclosure of the present application also includes any novel feature or novel combination of features disclosed herein either explicitly or implicitly or any generalization thereof, whether or not it mitigates any or all of the same technical problems as does the present invention. The applicants hereby give notice that new claims may be formulated to such features during the prosecution of the present application or any further application derived therefrom. STATISTICAL MODEL Nomenclature r,z Cylindrical Coordinates, m T Temperature, K k i Thermal conductivity of the material i=1, 2, 3, W/mK h Convective heat transfer coefficient, W/m 2 K q 0 heat generated per unit volume, W/m 3 q 1 heat flux applied per unit area, W/m 2 q=q 0 L 1 +q 1 , Effective heat flux, W/m 2 a radius of the lower cylinder, m b radius of the middle cylinder, m c radius of the upper cylinder, m L 1 height of the lower cylinder, m L 2 height of the middle cylinder, m L 3 height of the upper cylinder, m Q heat flow, W h c thermal contact conductance, W/K ΔT temperature drop across the interface, K k gap thermal conductivity of the gap, W/mK A gap area occupied by the gap, m 2 L gap length of the gap, m R gap resistance due to the gap, K/W P Percentage of area occupied by the nanotubes on silicon A Area of the thermal interface material layer, m 2 L Thickness of the thermal interface layer, m R eff Effective thermal resistance of the thermal interface layer, K/W K eff Effective thermal conductivity of the thermal interface layer, W/mK K bulk Thermal conductivity of the nanotubes, W/mK Subscripts ∞ ambient i 1, 2, 3 . . . An analysis was conducted of the TIM system for configurations in which the thickness of the heat source is also taken into account. Both specified heat generation and specified uniform heat flux can be applied to the system. The details of the analytical solution are given in Desai et al. 21 , expressly incorporated herein by reference. In Desai et al. 22 , expressly incorporated herein by references, numerical and analytical models are built for a periodic element (or a unit cell element) of the system of vertically aligned nanotubes between silicon and aluminum surfaces. The size of the periodic element is determined by the size of the nanotubes, and the percentage of area they occupy on the silicon surface (assuming they are uniformly distributed on the silicon surface). The size of the silicon surface is 1 cm×1 cm. The periodic element is assumed to be cylindrical. FIG. 7 represents one such periodic element. As can be seen from the micrographs shown in FIGS. 8 and 9 , the vertically aligned nanotubes grown on a silicon substrate do not have the same height. To take into account the size variation and to analyze the effect of this variation on the effective thermal conductivity of the system, a statistical approach is applied. An analytical solution presented in Desai et al. 21 is used along with a random number generator to represent variations in heights of nanotubes over the chip area. A statistical analysis may then be carried out on the different heights of the tubes and a corresponding temperature drop calculated for that system (combination of many unit cells). The results obtained indicate that considering a small system is sufficient to accurately model the effect of variation of height over the chip area. In practice, the nanotubes are grown off a surface (silicon) and the height to which the nanotubes grow cannot be controlled with great precision. Hence, there will be a small gap between some of the nanotubes and the aluminum interface. The analytical solution from Desai et al. 21 may be used for modeling a unit cell as shown in FIG. 7 . The variation in height is accounted for by taking the resultant temperature drop in the gap between the end of the nanotube and the aluminum surface in short tubes and applying the same as an interface temperature drop, as given by relation (1) below. R gap = L gap k gap ⁢ A gap ( 1 ) Then, Δ T gap =QR gap ,  (2) where k gap is the thermal conductivity of the gap, A gap is the area occupied by the gap, and L gap is the length of the gap. Q is the heat flowing through the nanotube. This model is then coupled with a random number generator, which assigns a height to the tubes randomly, and results obtained for a series of interations. The thermal resistance of each of the nanotubes is stored. The effective resistance of the thermal interface layer is calculated by combining the individual resistances in parallel. The effective resistance is then used to evaluate the one-dimensional effective thermal conductivity of the TIM layer using the relation, k eff = L R eff ⁢ A . ( 3 ) The result is a model of many vertical nanotubes to form a miniature version of the TIM system. Two different random distributions are considered. First is a normal random distribution with mean as the mean height of the nanotubes and standard deviation σ=1 micron. The second distribution is a uniform random distribution, which generates random numbers whose elements are uniformly distributed in the range of the mean, +/−3 micron. The results are compared for these two random distributions. Two different analyses are considered for modeling the effects of height variation across the thermal interface material. In the first analysis it is assumed that the nanotubes which are smaller than the mean height do not contribute to the effective thermal conductivity (i.e., the resistance of the matrix is very high so there is essentially no heat flowing through these tubes, K gap =0.001 W/mK). The second analysis uses equation (1) to determine the resistance of the short tube (K gap =4 W/mK), and then uses the resistance of the matrix material and the spreading resistance of the tube with the matrix material added. In the second case the short tubes also contribute to the effective conductivity calculation. This results in four different cases: 1) Normal finite—Normal random distribution with finite resistance for the short tube. In this case, short tubes contribute to the effective thermal conductivity of the TIM. 2) Normal infinite—Normal random distribution with infinite resistance for the short tube. So that short tubes do not contribute to the effective thermal conductivity of the TIM. 3) Uniform finite—Uniform random distribution with finite resistance for the short tube. In this case, short tubes also contribute to the effective thermal conductivity of the TIM. 4) Uniform infinite—Uniform random distribution with infinite resistance for the short tube, so that short tubes do not contribute to the effective thermal conductivity of the TIM. FIG. 10 , shows a plot of number of runs (same as the number of unit cells used in the model) versus the effective thermal conductivity of the matrix for a normal distribution with infinite resistance of the shorter nanotubes. 300 Iterations were required to obtain the required convergence for case 2. In the other cases similar convergence analyses were performed. For case 1, 300 iterations gave a converged solution. For case 3, 200 iterations and, for case 4, 100 iterations gave a converged solution. TABLE 1 Normal distribution effective conductivity values as a function of percentage of area occupied for finite resistance case. K bulk W/mK 2500 1000 500 P K eff /K bulk K eff /K bulk K eff /K bulk 10 0.063 0.071 0.079 30 0.169 0.185 0.201 50 0.272 0.286 0.317 Table 1 and FIG. 11 are the results obtained for the normal distribution with finite effective thermal conductivity analyses. The effective thermal conductivity is scaled with the bulk thermal conductivity of the nanotubes and is plotted against the percentage of area occupied by the nanotubes. The results indicate that taking the average of more than six runs (three lines shown in the plot) would result in the three lines shown here collapsing into a single line. The results for normal distribution with infinite resistance are presented in Table 2 and FIG. 12 . Plotting the dimensionless thermal conductivity against the percentage of area occupied by the nanotubes results in three lines that lie nearly on top of each other, converging all the data into a single line. TABLE 2 Normal distribution infinite effective conductivity values as a function of percentage of area occupied. K bulk W/mK 2500 1000 500 P K eff /K bulk K eff /K bulk K eff /K bulk 10 0.05 0.048 0.049 30 0.148 0.149 0.149 50 0.251 0.248 0.25 Table 3 and FIG. 13 show the results obtained for the uniform distribution with finite effective thermal conductivity analyses. The effective thermal conductivity is scaled with the bulk thermal conductivity of the nanotubes and plotted against the percentage of area occupied by the nanotubes. The results indicate that taking average of more than six runs (three lines shown in the plot) would result in the three lines shown here collapsing into a single line. TABLE 3 Uniform distribution finite effective conductivity values as a function of percentage of area occupied. K bulk W/mK 2500 1000 500 P K eff /K bulk K eff /K bulk K eff /K bulk 10 0.06 0.0637 0.0713 30 0.15 0.172 0.183 50 0.26 0.272 0.288 The results for uniform distribution with infinite resistance are presented in Table 4 and FIG. 14 . In FIG. 15 , the collapsed single line (linear fit line through all the lines in case of infinite resistance case and the centre line in case of the finite resistance case) in each case is plotted against the percentage of area occupied by nanotubes. The two lower lines lying on top of each other in FIG. 15 are the lines for infinite resistance case with normal and uniform distributions. They lie nearly on top of each other, as in both cases there are 50% of the tubes that are longer or of equal height as the gap and they contribute to the effective thermal conductivity and the other 50% do not contribute at all. In the uniform distribution with finite resistance the tubes shorter than the gap height contribute to the effective conductivity and hence this gives a higher effective thermal conductivity then the infinite resistance case. In the normal distribution with finite resistance case the tubes shorter than the gap height contribute to the effective conductivity with a tighter distribution of the height of the nanotubes towards the mean (normal distribution with σ=1) and hence this gives a higher effective thermal conductivity then the uniform distribution with finite resistance case. TABLE 4 Uniform distribution infinite resistance case effective conductivity values as a function of percentage of area occupied. K bulk W/mK 2500 1000 500 P K eff /K bulk K eff /K bulk K eff /K bulk 10 0.048 0.048 0.05 30 0.15 0.15 0.151 50 0.25 0.25 0.244 The results indicate that the normal distribution with finite resistance of short nanotubes case give the highest thermal conductivity of all the four cases. Also, a parametric analysis is carried out by varying the thermal conductivity of the nanotubes and the percentage of area they occupy on the silicon surface. By scaling the thermal conductivity with the bulk conductivity and plotting this against the percentage of area occupied, all the lines converge into a single line. The results indicate that, despite the effects of height variation, a thermal interface material with vertically aligned carbon nanotubes has the potential to be a high thermal conductivity thermal interface material. The word “comprising”, “comprise”, or “comprises” as used herein should not be viewed as excluding additional elements. The singular article “a” or “an” as used herein should not be viewed as excluding a plurality of elements. The word “or” should be construed as an inclusive or, in other words as “and/or”. REFERENCES [1] National Electronics Manufacturing Initiative (NEMI) Roadmap, 2005. [2] Interface Material Selection and a Thermal Management Technique in Second-Generation Platforms Built on Intel® Centrino™ Mobile Technology, Intel Technology Journal , E. C. Samson et al., Vol. 9, Issue 1, pp. 75-86, February 2005. [3] S. Berber, Y. K. Kwon, and D. Tomanek, “Unusually high thermal conductivity of carbon nanotubes,” Phys. Rev. Lett ., vol. 84, pp. 4613-4617, 2000. [4] S. Maruyama, “A molecular dynamics simulation of heat conduction of a finite length single-walled carbon nanotube,” Microsc. Thermophys. Eng ., vol. 7, pp. 41-50, 2003. [5] J. W. Che, T. Cagin, and W. A. Goddard, “Thermal conductivity of carbon nanotubes,” Nanotechnology , vol. 11, pp. 65-69, 2000. [6] P. Kim, L. Shi, A. Majumdar, and P. L. McEuen, “Thermal transport measurements of individual multiwalled nanotubes,” Phys. Rev. Lett ., vol. 87, no. 21, pp. 215502-1-215502-4, November 2001. [7] S. U. S. Choi, Z. G. Zhang, W. Yu, F. E. Lockwood, and E. A. Grulke, “Anomalous thermal conductivity enhancement in nanotube suspensions,” Appl. Phys. Lett ., vol. 79, pp. 2252-2254, 2001. [8] M. J. Biercuk, M. C. Llaguno, M. Radosavljevic, J. K. Hyun, A. T. Johnsond, and J. E. Fischer, “Carbon nanotube composites for thermal management,” Appl. Phys. Lett ., vol. 80, pp. 2667-2769, 2002. [9] M. Moniruzzaman, K. I. Winey, “Polymer nanocomposites containing carbon nanotubes”, Macromolecules, 39 (16): 5194-5205, 2006. [10] Q. Ngo, B. A. Gurden, A. M. Cassell, G. Sims, M. Meyyappan, J. Li, and C. Y. Yang, “Thermal interface properties of cu-filled vertically aligned carbon nanofiber arrays,” Nano Lett ., vol. 4, pp. 2403-2407, 2004. [11] J. Xu and T. S. Fisher, “Enhancement of thermal interface materials with carbon nanotube arrays,” Int. J. Heat Mass Transf , vol. 49, pp. 1658-1666, 2006, ibid, “Enhancement of thermal contact conductance using carbon nanotube arrays,” IEEE Trans. Comp. Packg. Tech . vol. 29, pp. 261-267, 2006. [12] H. Huang, C. Liu, Y. Wu, S. Fan, “Aligned carbon nanotube composite films for thermal management”, Adv. Mater, 17, pp. 1652-1656, 2005, ibid, “Effects of surface metal layer on the thermal contact resistance of carbon nanotube arrays”, APPL. PHYS. LETT. 87, 213108, 2005. [13] Tian, Weixue; Yang, Ronggui, “Effect of interface scattering on phonon thermal conductivity percolation in random nanowire composites,” 90 Applied Physics Letters 26: Art. No. 263105 Jun. 25, 2007. [14] Yang R G, Chen G, Dresselhaus M S, “Thermal conductivity of simple and tubular nanowire composites in the longitudinal direction”, 72 Physical Review B 12: Art. No. 125418 September 2005. [15] Z. F. Ren, Z. P. Huang, J. W. Xu, J. H. Wang, P. Bush, M. P. Siegal and P. N. Provincio, “Synthesis of large arrays of well-aligned carbon nanotubes on glass” 282 Science 1105 (1998). [16] Z. W. Pan, S. S. Xie, B. H. Chang, C. Y. Wang, L. Lu, W. Liu, W. Y. Zhou, W. Z. Li, and L. X. Qian, “Very long carbon nanotubes” 394 Nature 631 (1998). [17] Coquay, P., De Grave, E., Peigney, A., Vandenberghe, R. E. & Laurent, “C. Carbon nanotubes by a CVD method. Part I: Synthesis and characterization of the (Mg, Fe)O catalysts,” 106 Journal Of Physical Chemistry B 13186-13198 (2002)., ibid, “Carbon nanotubes by a CVD method. Part II: Formation of nanotubes from (Mg, Fe)O catalysts,” 106 Journal Of Physical Chemistry B 13199-13210 (2002). [18] Fischer J E, Zhou W, Vavro J, et al. “Magnetically aligned single wall carbon nanotube films: Preferred orientation and anisotropic transport properties,” JOURNAL OF APPLIED PHYSICS 93 (4): 2157-2163 Feb. 15 2003. [19] Garcia E J, Hart A J, Wardle B L, Slocum A H, “Fabrication and nanocompression testing of aligned carbon-nanotube-polymer nanocomposites,” 19(16) Advanced Materials 2151-+Aug. 17 2007. [20] Iijima S, “Helical microtubules of graphitic carbon”, Nature, Volume 354, Pages 56-58, 1991. [21] Anand Desai, James Geer, and Bahgat Sammakia, “Models of Steady State Heat Conduction in Multiple Cylindrical Domains”, Journal of Electronic Packaging, Volume 128, Number 1, Pages 10-17. [22] Anand Desai, James Geer, and Bahgat Sammakia, “An Analytical Study of Transport in a Thermal Interface Material enhanced with Carbon nanotubes”, Journal of Electronic Packaging, Volume 128, Number 1, Pages 92-97.

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CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 10 2010 004 424.5 filed Jan. 13, 2010, the entire contents of which are incorporated herein by reference. FIELD OF THE INVENTION [0002] The present invention pertains to a device for pressure equalization and for the controlled reduction of a volume flow of an electromechanically driven medical gas delivery means to a medical device for respirating (also known as ventilating) a patient, especially a respirator or an anesthesia apparatus. BACKGROUND OF THE INVENTION [0003] Valves for pressure reduction are known as pressure reducers from the state of the art and are used for monitoring. [0004] A respiration drive is designed in GB 2324122 B2 in the form of a radial flow compressor rotating at a high rpm. The respiration drive acts as a pressure source, which makes available a pressure rising with increasing rpm. Thus, the variation of the rpm is a manipulated variable for adapting the respiration pressure to the respiration situation, which means that the rpm must be cyclically increased and decreased again synchronously with the breathing cycle by varying the respiration pressure in such a way that the variation is resolved for individual breaths. [0005] U.S. Pat. No. 6,877,511 BB describes a variation of the respiration pressure for the inspiration and expiration phases of a compressor, which variation is brought about by acceleration and deceleration of a rotary compressor. [0006] In a medical gas delivery means driven electromechanically with variable air delivery capacity according to the state of the art, the particular pressure being currently delivered is brought about by varying the rpm as a function of an external actuating signal, for example, the signal of a respirator. [0007] A medical gas delivery means driven electromechanically with variable air delivery capacity comprises in the sense of the present invention a gas delivery means, gas delivery device or gas delivery unit in an embodiment with an electromechanical blower drive, radial flow compressor, rotary compressor, or side channel compressor. [0008] These variations of the rpm lead to accelerations and deceleration operations. The accelerations and decelerations of radial flow compressors and/or rotary compressors, which occur in a cumulative manner during the life of the product, impose very high requirements on temperature and media resistance, reliability and low wear for the components present in the device, such as shafts, bearings and seals, based on the intended use for supplying patients with clean breathing air. These requirements cannot be guaranteed in each application over the entire life of the product, so that some components must undergo maintenance or be replaced at certain time intervals. [0009] If the electromechanically driven medical gas delivery means is not operated variably but without being affected by an external actuating signal, the electromechanically driven medical gas delivery means must be operated permanently at the maximum necessary pressure level, even in the case in which the medical device being supplied does not continuously call for this pressure level for respirating a patient or the outlet of the electromechanically driven medical gas delivery means is blocked from time to time by closed valves in the respirator. [0010] Reliable self-cooling by the air stream being delivered is thus no longer available. The self-cooling by the air stream is essential especially if the radial flow compressor or rotary compressor is encapsulated in a housing part to achieve reduced noise generation. The temperature rise resulting herefrom leads to a thermal load for the components such as shafts, bearings and seals. Operation of the electromechanically driven medical gas delivery means without self-cooling is therefore disadvantageous with respect to the service life both for operation with and without variation of the rpm. An essential percentage of the wear is due to thermal load and to dynamic accelerations and deceleration operations brought about by the respiration control. SUMMARY OF THE INVENTION [0011] It is therefore advantageous to avoid dynamic accelerations and deceleration operations as much as possible. Increases in the respiration pressure to be applied can, of course, be brought about only by increasing the rpm of a radial flow compressor, but the respiration pressure can also be reduced by pneumatically relieving the pressure into the environment. However, the pressure relief must not counteract an increase in the respiration pressure intended by the user and is imposed on the medical device for respirating a patient and should take place independently from an actuation by an external actuating signal and without actively actuated components as parts of the electromechanically driven medical gas delivery means. [0012] The object of the present invention is to provide an overload protection for pressure equalization between an electromechanically driven medical gas delivery means and a medical device for respirating a patient. [0013] According to the invention, a device is provided for pressure equalization for an electromechanically driven medical gas delivery means in a medical device for respirating a patient. The device has a pressure relief unit comprising a first gas port and a second gas port comprising a relief valve with a valve disk and a valve crater. The device has a pressure relief outlet, an equalization space and a nonreturn valve. The valve disk of the relief valve is in pneumatic connection with the electromechanically driven medical gas delivery means via a front-side area and via a rear-surface area. The front-side area is made larger than the rear-side area. A front-side force acts on the valve disk via the front-side area and a rear-side force acts via the rear-side area at an operating pressure and a pressure level in the equalization space. A distance between the valve disk and the valve crater is determined by the operating pressure and the pressure in the equalization space and by the ratio of the front-side surface having the area to the rear-side surface having the area and by the ratio of the front-side force to the rear-side force, so that a partial volume flow of a volume flow, which is adapted to the operating state of the medical device for respirating a patient and to the operating state of the electromechanically driven medical gas delivery means, flows off into the environment via a bypass stream branch, via the relief valve and the pressure relief outlet. [0014] The device according to the present invention is arranged as a pressure relief unit in parallel arrangement in a bypass stream branch of a main stream branch carrying an air flow. The air flow is carried to a pressure sink through the main stream branch by an electromechanically driven medical gas delivery means, designed as a rotary compressor, side channel compressor or radial flow compressor. The pressure sink is a medical device for respirating a patient, especially a respirator or anesthesia apparatus. The medical device for respirating a patient takes a pressure from the electromechanically driven medical gas delivery means, which pressure varies cyclically with the respiration control, and this variation may also result in complete blockage of the main stream branch, besides in an unhindered, free flow from the medical device to the patient without an appreciable flow resistance or pressure drop up to the patient. The pressure relief unit comprises a relief valve, with a valve sealing element designed as a valve disk, with a flexible bellows and with a valve crater, a first gas port, a second gas port, a pressure relief outlet, an equalization space, as well as a nonreturn valve with a nonreturn valve sealing element and with a nonreturn valve crater (valve seat). [0015] The valve disk is connected with the flexible bellows in such a way that the valve disk is arranged such that it is movable in the direction of the first gas port towards the valve seat. The compressed air pressure relief unit seals, with the relief valve, the amount of removed air into the bypass stream branch on the inlet side against the amount of air being delivered by the electromechanically driven medical gas delivery means in the main stream branch if the pressure sink calls for an amount of air from the electromechanically driven medical gas delivery means. The electromechanically driven medical gas delivery means, designed as a rotary compressor, side channel compressor or radial flow compressor, is cooled in this case by the flowing air stream, and the amount of heat generated in the interior of the housing of the gas delivery means is effectively removed by this self-cooling to the outside. The relief valve closes the pressure relief outlet in this case based on the prestress of the flexible bellows with the front side of the valve disk against the valve seat, so that no amount of air can escape into the environment via the pressure relief outlet. The front side of the valve disk seals off the amount of air in the first gas port via a front-side surface A 1 . The bellows arranged on the rear side of the valve disk is in pneumatic connection on the rear side with the amount of air in the second gas port of the pressure relief unit via a rear-side surface A 2 . The rear-side surface A 2 opposing the amount of air present on the rear side is made smaller than the front-side surface A 1 opposing the amount of air located on the front side. [0016] The nonreturn valve with the nonreturn valve sealing element and with the nonreturn valve seat is arranged between the rear-side surface A 2 of the valve disk with the bellows and the second gas port of the pressure relief unit. The nonreturn valve seat is arranged towards the second gas port of the pressure relief unit, so that the nonreturn valve element seals against this nonreturn valve seat in such a manner that no air flow is possible from the first gas port into the buffer volume in the direction of the second gas port of the pressure relief unit, but an amount of air and pressure levels corresponding to this amount of air can reach the buffer volume and hence the rear-side surface A 2 of the valve disk from the second gas port. [0017] If the pressure sink does not receive any volume flow from the electromechanically driven medical gas delivery means, i.e., the main stream branch is fully blocked on the outlet side, for example, by a closed dispensing valve in the medical device for respirating a patient, the relief valve is opened, so that air can reach the pressure relief outlet from the first gas port and can flow off into the environment. Without a gas flow through the pressure relief outlet, the amount of heat generated in the interior of the housing would not be able to be removed to the outside. Gas-delivering states are thus obtained for the electromechanically driven medical gas delivery means, in which the amount of air being delivered cools the electromechanically driven medical gas delivery means, both when the main stream branch is blocked by the dispensing valve of the medical device for respirating a patient via the pressure relief outlet and when the main stream branch is unblocked through the main stream branch itself. [0018] The mode of operation of the pressure relief unit and of the individual components will be explained in more detail below based on this state as a first working point of an outlet-side blockage of the main stream branch with the main stream branch blocked and on a first operating pressure p w,1 in the main stream branch. [0019] A first front-side pressure p F,1 corresponding to the first working operating pressure p w,1 acts on the front-side surface A 1 of the valve disk from the side of the first gas port. [0020] A first rear-side pressure p B,1 corresponding to the first operating pressure p w,1 acts on the system comprising the valve disk and the bellows from the side of the second gas port on the rear-side surface A 2 . [0021] A couple of forces acting in the opposite direction with F F,1 on the front side of the valve disk and F B,1 on the rear side of the valve disk is obtained via the surfaces A 1 and A 2 of the valve disk from the front-side pressure p F,1 and the rear-side pressure p B,1 . Since the surface A 1 of the valve disk acting on the front side is larger than surface A 2 of the valve disk acting on the rear side, the valve disk is moved away from the sealing crater in the direction of the second gas port. The relief valve is thus open. [0022] This means that when the main stream branch is closed, an amount of air corresponding to the amount of air being delivered from the pressurized gas source enters the environment via the pressure relief outlet through the bypass stream branch and the sealing crater (seat) from the electromechanically driven medical gas delivery means. The nonreturn valve is closed in this first working point, so that air can flow from the main stream branch via the second gas port into the buffer volume between the bellows and the valve disk and the nonreturn valve on the rear side of the valve disk, so that the first operating pressure p w,1 is present in the buffer volume. [0023] The conditions for triggering an opening operation of the relief valve can be summarily described in the general form as follows. [0024] Starting from any desired operating pressure p w,x , the amount of air removed by the pressure sink, i.e., a volume flow flowing through the main stream branch must drop to such an extent, or stop, that the operating pressure rises to a pressure p w,y in such a way that a force F F,y , which is greater than the force F B,x acting on the rear side of the pressure disk and being due to a prevailing (stored) pressure value p V,x and the surface A 2 acting on the rear side, is obtained via the surface A 1 of the front side of the valve disk, which said surface acts on the front side, so that the relief valve partially or fully opens. [0025] If an amount of air is taken from the medical device for respirating a patient, preferably a respirator or anesthesia apparatus, at a second working point, with the main stream branch not blocked, a second operating pressure p w,2 , which is a lower operating pressure than the first operating pressure p w,1 , becomes established in the main stream branch. A rear-side force F F,2 acting on the valve disk of the relief valve results from the operating pressure p w,2 and the surface A 1 of the valve disk of the relief valve, which said surface acts on the front side. The pressure drop resulting in the main stream branch from the elimination of the blockage of the main stream branch causes a pressure difference at the nonreturn valve, so that the nonreturn valve sealing element of the nonreturn valve, which said element is preferably designed as a diaphragm, is pressed against the nonreturn valve seat and no pressure equalization to the main stream branch can take place via the second gas port of the pressure relief unit. The first operating pressure p w,1 is thus maintained in the equalization space and it is stored in the equalization space as a pressure value p V,1 almost without a time delay. [0026] This stored (prevailing) pressure value p V,1 continues to act unchanged on the rear side on the valve disk of the relief valve with the surface A 2 of the relief valve such that there is a force F B,1 on the valve disk acting on the rear side. The force ratios at the valve disk of the relief valve change due to the pressure change p w,2 . [0027] The force F B,1 acting on the rear side of the valve disk of the relief valve is now greater than the front-side force F F,2 , which results from the operating pressure p w,2 . This brings about closure of the relief valve. [0028] After completion of the closing operation of the relief valve, the pressure p V,1 in the equalization space is released by the relative motion of the bellows, which motion is coupled with the motion of the valve disk, to a pressure value p V,1 , which is slightly lower than the pressure level p V,1 that was previously present. [0029] The conditions for triggering a closing operation of the pressure relief valve can be summarily described in the general form as follows. [0030] Starting from any desired operating pressure p w,x , the amount of air removed by the pressure sink, i.e., a volume flow flowing through the main stream branch, must be so large that the operating pressure will drop to a pressure which results over the effective surface A 1 of the front side of the valve disk in a force F F,z that is weaker than the force F B,x resulting from a prevailing (stored) pressure value p V,x and the surface A 2 acting on the rear side on the rear side of the valve disk, so that the relief valve partly or completely closes. [0031] The opening and closing characteristic of the relief valve is set by dimensioning surface A 1 of the valve disk, which surface acts on the front side and surface A 2 of the valve disk, which latter surface acts on the rear side and by the area ratio QA=A 1 /A 2 resulting therefrom. Ratio QA is preferably selected in a range of 1.1 to 2.0 and especially preferably in a range of about 1.5 to 1.6. The front-side surface A 1 preferably has a front-side surface A 1 with an effective surface area of 60 mm 2 to 80 mm 2 , and the front-side surface A 1 is especially preferably designed with an effective surface area of 70 mm 2 . The rear-side surface A 2 preferably has an effective surface area of 35 mm 2 to 55 mm 2 , and the rear-side surface A 2 is especially preferably designed with an effective surface area of 45 mm 2 . The opening and closing characteristic is adapted to the working pressure ratios arising from the combination of an electromechanically driven medical gas delivery means preferably designed as a radial flow compressor or rotary compressor and a pressure sink preferably designed as a medical device for respirating a patient and especially preferably as a respirator or anesthesia apparatus. A typical operating pressure for an electromechanically driven medical gas delivery means designed as a radial flow compressor for operating a respirator is in a range of 30 mbar to 60 mbar. A typical value at which the relief valve releases the pressure relief outlet and air streams from the main stream branch via the bypass stream branch into the environment is in the range of 70 mbar to 100 mbar. [0032] The advantage of the relief valve according to the present invention over a solution with a pressure relief valve in which the pressure relief valve is opened beginning from a defined pressure (pressure limit) is the variability of the operating pressure. The relief valve functions at any desired working point of the electromechanically driven medical gas delivery means as long as the difference between the pressure levels p w,1 and p w,2 is great enough. [0033] In a special embodiment, a dispensing element is present in the equalization space. This dispensing element guarantees that during changes in the operating pressure p w,1 , the corresponding prevailing (stored) pressure value p V,1 in the equalization space can adapt itself to these changes. The adaptation takes place due to a pressure equalization towards the environment. The nonreturn valve would remain closed without a dispensing element in case of a decreasing operating pressure at a prevailing (stored) pressure value p V,1 in the equalization space, which pressure value is higher than the operating pressure p w,1 . The force F B,1 acting on the rear side of the valve disk of the relief valve would now be lastingly stronger than the front-side force F F,2 that results from the operating pressure p w,2 , so that the relief valve would no longer open. [0034] A dispensing element is necessary especially if the electromechanically driven medical gas delivery means shall not be operated statically at a working point with an operating pressure but at different working points with an operating pressure set continuously or in a stepwise variable manner. [0035] The dispensing element is designed such that the pressure equalization time via the dispensing element is in the range of about 5 minutes in the case of the application in which the pressure sink is a medical device for respirating a patient, preferably a respirator, especially an intensive respirator. The dispensing element represents a pneumatic resistance R (resistance). [0036] The following possibilities of technical solutions, for example, a dispensing diaphragm, an air-permeable membrane filter, a sintered filter or even combinations of sintered elements, membranes and diaphragm elements, may be considered for a practice-oriented implementation of the dispensing element. These possible solutions make it possible to generate a pneumatic resistance. A dispensing diaphragm is preferably used, and a dispensing diaphragm with round dispensing opening is especially preferred. The dispensing opening may be preferably prepared by machining by milling or by means of laser machining. Holes with a diameter in the range of a few μm can thus be prepared in a reproducible manner. [0037] The duration is set by selecting a predetermined width of opening of the dispensing element combined with the volume contained in the equalization space. [0038] The volume or its special pneumatic property, the compliance C, cooperates with the pneumatic resistance R as a pneumatic time constant τ. [0000] τ=R·C [0000] The compliance is determined here both by the volume contained in a space element or container and by the properties of the outer wall of a dispensing element predetermined in the space element or container. The compliance values needed for the application can be embodied by correspondingly selecting the material, for example, by using either an essentially flexible elastic material or a predominantly solid nonelastic material for the outer wall of the container in conjunction with the material thickness of the outer wall of the container. For the application of the pressure relief unit in a medical device for respirating a patient, the equalization process over time between the equalization space and the environment via the dispensing element shall have concluded completely with a duration of about 3 minutes to 5 minutes. Under the physically generally valid precondition that an equalization process is concluded at a rate of 95% with five times the duration of a time constant τ, a value of one minute is obtained for τ from an equalization time of 5 minutes. [0039] With a pneumatic compliance C of [0000] C = 0.22  mL m   bar [0000] which is predetermined by the dimensions and the material selected for the equalization space, a necessary pneumatic resistance R is obtained as [0000] R = 4545  m   bar · min L [0000] as the basis for dimensioning the dispensing element. [0040] For an embodiment with a dispensing diaphragm, the width of opening of the opening in the dispensing diaphragm is preferably selected in the range of 0.002 μm 2 to 0.008 μm 2 for an equalization space of 0.2 L to 0.3 L resulting from the compliance indicated, which corresponds to a diameter of about 50 μm to 100 μm and results in a duration of about 5 minutes in case of a round dispensing opening. [0041] In another embodiment, the dispensing element is not connected pneumatically with the environment, but the dispensing element is in connection via an equalization line with an air stream branch guiding the air flow from the gas delivery means to the medical device for respirating a patient. In an arrangement of the pressure relief unit in the bypass stream branch, the dispensing element is preferably in connection with the main stream branch or with the bypass stream branch via an equalization line. It is also preferable to connect the equalization line from the dispensing element pneumatically with the bypass stream branch in the direction of the medical device for respirating a patient, and it is also preferable to connect it with the second gas port of the pressure relief unit. Due to the pressure in the main stream branch and in the bypass stream branch being increased by approximately 30 mbar to 60 mbar relative to the environment and to a pressure level in a range of 70 mbar to 100 mbar being present in the equalization space before opening the relief valve and discharge via the pressure relief outlet, the pressure gradient between the equalization space and the pressure in the main stream branch or bypass stream branch is made lower by about 40% to 70% than the pressure difference between the pressure level in the equalization space and the environment. The consequence of this lower pressure gradient is that the equalization process takes place substantially more slowly in the main stream branch or bypass stream branch than a pressure equalization against the environment with equal dimensioning of the equalization space and dispensing element. In an inversion of the argument, the volume of the equalization space can thus be reduced at equal predetermined duration of the equalization process equaling 3 minutes to 6 minutes. The volume of the equalization space can thus be selected in a range below 0.1 L when dimensioning the time constant τ. [0042] In another embodiment, the elastic bellows is designed such that it is free from prestress. Thus, the bellows does not act complement or counteract the forces F F , F B acting on the front side and on the rear side, which forces result from the pressure values p w,1 , p w,2 and the area ratio QA. [0043] In a special embodiment, the elastic bellows is provided with a prestress. Thus, the bellows acts with or against the forces F F , F B acting on the front side and on the rear side, which forces result from the pressure values p w,1 , p w,2 and the area ratio QA. It is possible as a result to adapt the areas A 1 , A 2 to the design needs; in particular, it is thus possible to reduce the rear-side area A 2 , because a part of the force F B acting on the rear side is applied by a prestress of the bellows, which is designed, for example, as a spring. [0044] However, the prestress can also be set in a preferred embodiment by selecting the elasticity of the material and/or the thickness of the material of the bellows. In another preferred embodiment, it is possible to apply a nonlinear force component to the valve disk by means of the prestress of the bellows, besides the area ratio QA, which linearly applies a continuous force to the valve disk independently from the path of the bellows and the state, the force applied to the valve disk increasing with increasing path of the bellows, i.e., being designed as a force acting progressively. [0045] The present invention will be explained in more detail with reference to the drawings attached, where identical reference numbers designate identical features. The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. BRIEF DESCRIPTION OF THE DRAWINGS [0046] In the drawings: [0047] FIG. 1 is a schematic view showing the basic structure of a pressure relief unit according to the invention; [0048] FIG. 2 a is a schematic view showing the pressure relief unit according to FIG. 1 in a first view with an electromechanically driven medical gas delivery means with a respirator. [0049] FIG. 2 b is a schematic view showing the pressure relief unit according to FIG. 1 in the first view with the electromechanically driven medical gas delivery means with the respirator; [0050] FIG. 3 a is a schematic view showing the pressure relief unit according to FIG. 1 in a second view of the electromechanically driven medical gas delivery means and with the respirator; [0051] FIG. 3 b is a schematic view showing the pressure relief unit according to FIG. 1 in the second view of the electromechanically driven medical gas delivery means and with the respirator; [0052] FIG. 4 is a schematic view showing a variant of the pressure relief unit according to FIG. 1 with an electromechanically driven medical gas delivery means and with a respirator; and [0053] FIG. 5 is a perspective exploded view and aa cross sectional exploded view showing another view of the pressure relief unit according to FIG. 1 . DESCRIPTION OF THE PREFERRED EMBODIMENTS [0054] Referring to the drawings in particular, FIG. 1 shows a pressure relief unit 1 according to the present invention with a first gas port 2 , with a second gas port 3 , with a relief valve 4 , comprising a valve disk 5 , a flexible bellows 6 and a valve seat 7 , with a pressure relief outlet 8 to an environment 33 , with an equalization space 9 , with a dispensing element 10 , with a nonreturn valve 11 , comprising a nonreturn valve sealing element 12 and a nonreturn valve seat 13 . The pressure relief unit 1 is designed as follows. [0055] Valve disk 5 is connected with the flexible bellows 6 in such a way that the valve disk 5 is arranged movably and is prestressed preferably in the direction of the valve seat 7 , so that the valve disk 5 lies or almost lies on the valve seat 7 in a pressureless and flow-free state and the pressure relief outlet 8 is largely closed in the direction of the environment 33 in the pressureless and flow-free state. Valve disk 5 is in connection with the front-side surface 51 of valve disk 5 , which said surface 51 has an area A 1 , via the first gas port 2 . Valve disk 5 is in connection with the internal diameter of bellows 6 via the equalization space 9 and the nonreturn valve 11 is in connection with the rear-surface surface 52 of valve disk 5 , which said surface 52 has an area A 2 . Pressure equalization continuously takes place between the equalization space 9 and the environment 33 via the dispensing element 10 . The ratio of the front-side area A 1 51 of valve disk 5 to the rear-side area A 2 52 of the valve disk 5 is designed for a value in the range of 1.1 to 2.0. The front-side surface 51 with the area A 1 of the valve disk 5 preferably has an effective surface of 60 mm 2 to 80 mm 2 , and the rear-side surface 52 with the area A 2 of the valve disk 5 preferably has an effective surface of 35 mm 2 to 55 mm 2 . [0056] In FIGS. 2 a and 3 b , the pressure relief unit 1 according to FIG. 1 is arranged in parallel in a bypass stream branch 30 of a main stream branch 20 carrying an air flow 40 in a combination with a medical device for respirating a patient with pneumatic connection with a patient. The medical device for respirating a patient is shown in these FIGS. 2 a and 2 b in a schematic view as an example as a respirator 60 . FIG. 2 a shows the design features in a schematic view and shows the pressure relief unit 1 according to FIG. 1 in a first operating state. FIG. 2 b additionally shows pressure ratios and force ratios, wherein the design features are identical to the features shown in FIG. 2 a . Not all the design features shown in FIG. 2 b are provided with reference numbers. The air flow 40 enters the pressure relief unit 1 to the relief valve 4 via the first gas port 2 . Equalization space 9 is connected with the main stream branch 20 via the second gas port 3 and the nonreturn valve 11 . A pressure equalization continuously takes place via the dispensing valve 10 between the equalization space 9 and the environment 33 ( FIG. 1 ). [0057] Identical elements in FIGS. 2 a and 2 b are designated by the same reference numbers as in FIG. 1 . [0058] A volume flow 40 is carried by the main stream branch 20 from an electromechanically driven medical gas delivery means 50 to a respirator 60 . The respirator 60 removes a volume flow 40 from the electromechanically driven medical gas delivery means 50 and represents a pressure sink. Respirator 60 removes a volume flow 40 varying cyclically with the respiration of a patient 70 and/or the control of the respirator 60 from the electromechanically driven medical gas delivery means 50 . The air is carried from the respirator to the patient 70 via feed lines 67 . As a result, the pressure level p w in the main stream branch 20 and the bypass stream branch 30 varies cyclically with the respiration of the patient 70 and/or the control of the respirator 60 . A typical operating pressure in the main stream branch 20 is in the range of 50 mbar to 80 mbar. [0059] In this arrangement according to FIGS. 2 a and 2 b , the respirator 60 is in the first operating state, in which the respirator 60 does not take over any volume flow 40 from the electromechanically driven medical gas delivery means 50 , during one time interval of the respiration cycle. The respirator 60 blocks the main stream branch 20 by closing means 66 present in the respirator 60 . The operating pressure in the main stream branch 20 then rises to a value p w,1 21 of 70 mbar to 100 mbar. [0060] Nonreturn valve 11 is open towards the second gas port 3 during this time interval of the respiration cycle, and a pressure equilibrium is obtained in this first operating state on the front side and the rear side of the valve disk 5 . The current operating pressure p w,1 21 is present on the front side as a front-side pressure p F,1 25 , and the current operating pressure p w,1 21 is present on the rear side of the valve disk 5 as a rear-side pressure p B,1 26 , so that the pressure ratios in the relief valve 4 are equalized and the current operating pressure p w,1 is also present as an identical pressure level p V,1 22 in the equalization space 9 . The pressure level in the equalization space 9 becomes equalized with the pressure in the environment 33 with a time delay over several respiration cycles via the dispensing element 10 ( FIG. 1 ). [0061] The duration of this equalization process is selected in a range of about five minutes in an intensive respirator. This duration is set as a time constant τ via a predetermined pneumatic resistance R, for example, by a predetermined width of opening of dispensing element 10 and by the pneumatic compliance C of equalization space 9 . [0062] The pressure level p V,1 in the equalization space 9 , identical to the current operating pressure p w,1 21 , is present as a rear-side pressure p B,1 on the rear side at the valve disk 5 . [0063] A force F F,1 43 is obtained at the relief valve 4 via the surfaces 51 , 52 of valve disk 5 with the areas A 1 , A 2 and via the front-side pressure p F,1 at the valve disk 5 on the front side of the valve disk 5 , and a force F B,1 44 is obtained on the rear side of the valve disk with the rear-side pressure p B,1 . The front-side force F F,1 43 is greater than the rear-side force F B,1 44 at the pressure equilibrium existing in the first operating state between the front-side and rear-side pressures p w,1 21 , p B,1 26 due to the fact that the front-side surface 51 of the valve disk 5 , which said surface has the area A 1 , is larger than the rear-side surface 52 of valve disk 5 , which said surface 52 has the area A 2 . When adding the forces F F,1 43 and F B,1 44 acting in opposite directions, a front-side force acting on the valve disk 5 is obtained in this constellation of forces as a resulting force, so that the valve disk 5 is moved away from the valve seat 7 and the pressure relief outlet 8 is released. A volume flow component 41 of the volume flow 40 thus flows via the opened relief valve 4 from the main stream branch 20 into the environment 33 via the bypass stream branch 30 through the pressure relief outlet 8 . [0064] In FIGS. 3 a and 3 b , the pressure relief unit 1 according to FIG. 1 is arranged in parallel in a bypass stream branch 30 of a main stream branch 20 carrying an air flow 40 in a combination with a medical device for respirating a patient with pneumatic connection with a patient. The medical device for respirating a patient is shown in these FIGS. 3 a and 3 b as an example as a respirator 60 in a schematic view. FIG. 3 a shows in a schematic view the design features and shows the pressure relief unit 1 according to FIG. 1 in a second operating state. FIG. 3 b additionally shows pressure ratios and force ratios, wherein the design features are identical to the features shown in FIG. 3 a . Not all the design features shown in FIG. 3 b are provided with reference numbers. The air flow 40 enters via the first gas port 2 and the pressure relief unit 1 to the relief valve 5 . The equalization space 9 is connected with the main stream branch 20 via the second gas port 3 and the nonreturn valve 11 . Pressure equalization continuously takes place between equalization space 9 and the environment 33 via the dispensing element 10 . [0065] Identical elements in FIGS. 3 a and 3 b are provided with the same reference numbers as in FIG. 1 . [0066] A volume flow 40 is sent through the main stream branch 20 from an electromechanically driven medical gas delivery means 50 to a respirator 60 . The respirator 60 removes a volume flow 40 from the electromechanically driven medical gas delivery means 50 and represents a pressure sink. The respirator 60 removes a volume flow 40 varying cyclically with the respiration of a patient 70 and/or the control of the respirator 60 from the electromechanically driven medical gas delivery means 50 . The air is sent from the respirator to the patient 70 via feed lines 67 . As a result, the pressure level p w in the main stream branch 20 and the bypass stream branch 30 varies cyclically with the respiration of the patient 70 and/or the control of the respirator 60 . [0067] In this arrangement according to FIGS. 3 a and 3 b , the respirator 60 is in the second operating state during a time interval of the respiration cycle, in which operating state the respirator 60 removes a volume flow 40 from the electromechanically driven medical gas delivery means 50 . [0068] Respirator 60 sends the volume flow 40 from the main stream branch 20 via feed lines 67 to the patient 70 . Closing means 66 present in the respirator 60 does not bring about any blockages of the main stream branch 20 during the current time interval of the respiration cycle. A typical operating pressure p w in the main stream branch 20 is in the range of 50 mbar to 80 mbar. [0069] Due to the fact that the equalization space 9 has been placed under the pressure level p V,1 via the second gas port 3 in a state such as the state described in connection with FIGS. 2 a and 2 b , due to the respiration cycle, recurring in time immediately before this current time interval, the pressure level p V,1 21 still continues to be present in the equalization space 9 even during this current time interval of the respiration cycle and acts as a rear-side pressure p B,2 28 . This pressure level p V,1 21 or the rear-side pressure p B,2 28 is higher than the current operating pressure p w,2 23 currently present now in the main stream branch 20 and the bypass stream branch 30 . The nonreturn valve 11 thus closes with the nonreturn valve sealing element 12 against the nonreturn valve seat 13 and the connection between the equalization space 9 and the second gas port 3 is interrupted and the pressure level p V,1 , continues to prevail (be stored) in the equalization space 9 . [0070] The pressure level p V,1 that has hitherto been present in the equalization space 9 becomes equalized with the pressure in the environment 33 ( FIG. 1 ) with a time delay over several breathing cycles via the dispensing element 10 until a pressure level p V,2 24 is reached in the equalization space 9 . [0071] The duration of this equalization process is selected in a range of about 5 minutes in an intensive respirator. This duration is set via a predetermined resistance R, for example, by a predetermined width of opening of the dispensing valve 10 and by the pneumatic compliance C of the equalization space 9 . [0072] The operating pressure p w,2 23 currently present now acts as a front-side pressure p F,2 27 on the front side on the valve disk 5 . Due to the fact that the pressure level p V,1 21 prevailing (being stored) as a rear-side pressure P B,2 28 is higher than the current operating pressure p w,2 23 currently present in the main stream branch 20 and the bypass stream branch 30 , different force ratios are obtained at the relief valve 4 . A force F F,2 45 acts on the front side of the valve disk 5 and the rear-side force F B,2 46 acts on the rear side of the valve disk via the surfaces 51 , 52 with the areas A 1 , A 2 and the pressure ratio from the pressure level p V,1 21 in the equalization space 9 as the rear-side pressure p B,2 28 and the current operating pressure p w,2 23 . The rear-side force F B,2 acting now is unchanged in this second operating state compared to the rear-side force F B,1 44 acting in the first operating state, because the pressure level p V,1 21 has been stored due to the closing of the nonreturn valve 11 in the equalization space 9 and continues to be present as a rear-side pressure p B,2 28 on the rear side of the valve disk 5 . The front-side force F F,2 45 is lower in this second operating state than the rear-side force F B,2 46 acting in the first operating state due to the reduction of the operating pressure from p w,1 21 to a pressure level p w,2 23 with the front-side pressure p F,2 27 resulting therefrom. When adding the opposite forces F F,2 45 and F B,2 46 , a front-side force acting on the valve disk 5 is obtained in the constellation of forces as a resulting force, so that the valve disk 5 is moved with the elastic bellows 6 in the direction of the valve seat 7 . [0073] This results in closing of the relief valve 4 , and the pressure relief outlet 8 is largely closed against the environment 33 , so that the volume flow 40 flows nearly completely from the electromechanically driven medical gas delivery means 50 through the main stream branch 20 to the respirator 60 and no volume flow component 41 ( FIGS. 2 a and 2 b ) of the volume flow 40 is sent into the environment 33 . [0074] A special variant of the pressure relief unit 1 according to FIG. 1 is shown in FIG. 4 arranged in parallel in a bypass stream branch 30 of a main stream branch 20 carrying an air flow 40 in a combination with a medical device for respirating a patient with pneumatic connection with a patient. [0075] In a schematic view, FIG. 4 shows the design features and the designation of the pressure relief unit 1 according to FIG. 1 in the first operating state, wherein the medical device for respirating a patient is shown in a schematic view as an example as a respirator 60 . [0076] Identical elements in FIG. 4 are designated by the same reference numbers as in FIG. 1 . [0077] The air flow 40 enters the pressure relief unit 1 and reaches the relief valve 4 via the first gas port 2 . The equalization space 9 is connected with the main stream branch 20 via the second gas port 3 and the nonreturn valve 11 . [0078] A volume flow 40 is sent through the main stream branch 20 from an electromechanically driven medical gas delivery means 50 to a respirator 60 . The respirator 60 removes a volume flow 40 from the electromechanically driven medical gas delivery means 50 and represents a pressure sink. The respirator 60 removes a volume flow 40 varying cyclically with the respiration of a patient 70 and/or the control of the respirator 60 from the electromechanically driven medical gas delivery means 50 . The air is sent via feed lines 67 to the patient 70 from the respirator. [0079] Pressure equalization continuously takes place between the equalization space 9 and the second gas port 3 via the dispensing element 10 by means of an equalization line 100 . [0080] In this arrangement according to FIG. 4 , the respirator 60 is in an identical operating state as in the arrangement according to FIGS. 2 a and 2 b . The pressure relief unit 1 is shown in a first operating state in a time interval of the respiration cycle, in which the respirator 60 does not take over any volume flow 40 from the electromechanically driven medical gas delivery means 40 . The respirator 60 blocks the main stream branch 20 by closing means 66 located in the respirator 60 . [0081] The nonreturn valve 11 is opened towards the second gas port 3 during this time interval of the respiration cycle, and a pressure equilibrium is obtained in this first operating state on the front side and the rear side of the valve disk 5 , so that the pressure ratios are equalized in this relief valve 4 and the current operating pressure is also present as an identical pressure level in the equalization space 9 . The equalization space 9 is in pneumatic connection with the rear side of the nonreturn valve 12 via the equalization line 100 and thus with the second gas port 3 . An equalization volume flow 110 thus flows from the equalization space 9 in the direction of the second gas port 3 as soon as the pressure level in the equalization space 9 is higher than the pressure level in the second gas port 3 . The pneumatic connection with the second gas port 3 by means of the equalization line 100 of the dispensing element 10 makes it possible for the volume of the equalization space 9 to be able to be selected to be smaller than in the solutions according to FIGS. 1 , 2 a , 2 b , 3 a , 3 b , in which the dispensing element 10 is in pneumatic connection with the environment 33 ( FIG. 1 ). [0082] FIG. 5 shows a pressure relief unit 1 according to the present invention according to FIG. 1 in a combination of a three-dimensional view and a longitudinal section. [0083] Identical elements in FIG. 5 are designated by the same reference numbers as in FIG. 1 . [0084] The pressure relief unit 1 comprises a first gas port 2 , a second gas port 3 to an environment 33 , a relief valve 4 , a pressure relief outlet 8 , an equalization space 9 , a dispensing element 10 , and a nonreturn valve 11 . The relief valve 4 comprises a valve disk 5 with a valve seat 7 . The valve disk 5 is connected with a space 9 via a flexible bellows 6 in a gas-tight manner. An equalization space 9 is used as a pressure storage means and is closed on the side of the second gas outlet 3 by the nonreturn valve 11 . Space 0 . 9 has an opening into the environment 33 via a dispensing element 10 . The valve disk 5 is pressed by a horizontal motion against the sealing crater 7 in case of a correspondingly great difference between the operating pressure p w and the pressure p V in space 9 and thus closes the pressure relief outlet 8 between the first gas port and the environment 33 . [0085] While specific embodiments of the invention have been described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

4y

BACKGROUND OF THE INVENTION In U.S. Pat. Nos. 3,813,320 and 3,834,988 (of which the applicant herein is a co-inventor), there are shown various media and various microorganisms which produce glucose isomerase. U.S. Pat. No. 3,813,320 involves the use of Aerobacter levanicum in a two-stage fermentation procedure using unpurified hardwood sulfite liquor as part of the medium in the second stage where the glucose isomerizing enzyme is produced. U.S. Pat. No. 3,834,988 shows the production of glucose isomerizing enzymes from an organism of the Actinoplanes genus in a medium whose principal constituent is corn steep liquor which has had the sludge removed. In the patent and scientific literature there are disclosures of other microorganisms which produce glucose isomerizing enzymes. Some of these enzymes convert D-glucose to D-fructose through one or more chemical intermediates (e.g., D-glucose-6-phosphate) but these enzymes do not appear to be practical for industrial use at the present time. More promising are enzymes known as glucose isomerase that convert D-glucose to D-fructose directly. A number of these enzymes have been prepared from microorganisms of the genera lactobacillus, Pseudomonas, Pasteurella, Leuconostoc, Streptomyces and Aerobacter (see review by Yamanaka in Biochem. Biophys, Acta 151, 670-680). In order that a significant quantity of glucose isomerase be formed by any of the foregoing microorganisms, xylose or xylan must be present in the growth medium to induce the enzyme. Pure xylose is relatively expensive, and when xylan is used in the growth medium, the microorganism must also produce enzymes capable of hydrolyzing the xylan. In order to overcome the expense of growing the microorganism in a xylose or xylan-containing medium, efforts have been expended to obtain a bacterium that will produce the enzyme constitutively. Lee, Hayes and Long (U.S. Pat. No. 3,645,848) have disclosed that certain strains of microorganisms belonging to the genus Arthrobacter are capable of producing enzymes that directly convert glucose or xylose to the corresponding ketose when grown in a medium from which xylose or xylan is absent. Relatively small amounts of isomerase are produced and the growth medium requires relatively expensive nitrogen sources, such as yeast extract and meat protein. SUMMARY OF THE INVENTION Accordingly, one of the principal objects of the present invention is to provide a method of growing microorganisms possessing enzymes for converting aldoses to ketoses using a medium which is relatively inexpensive and which results in good yields of enzyme. This invention comprises a method of producing glucose isomerizing enzyme in a medium comprising molasses, corn steep liquor (preferably filtered to remove the sludge) and an inorganic nitrogen salt. DETAILED DESCRIPTION I have discovered that microorganisms which produce glucose isomerase are capable of being grown in large numbers on a medium of which the principal ingredients are beet molasses, corn steep liquor, and an inorganic nitrogen salt. The preferred microorganism is of the genus Actinoplanes, but other glucose isomerizing organisms of the genera Lactobacillus, Pseudomonas, Pasteurella, Leuconostoc, Streptomyces, Aerobacter, Arthrobacter, Bacillus, Nocardia, Micromonospora, Microbiospora, Microellobospora, Thermoactinomyces, Thermopolyspora, Thermomonospora and Pseudonocardia can be grown on this medium. GROWTH OF SEED INOCULUM A seed inoculum of Actinoplanes missouriensis NRRL B-3342 is grown up by shaking at 28° C. for 24 hours in a 1-liter Erlenmeyer flask containing 400 ml. of inoculum media which consists of 0.25% glucose, 0.25% dipotassium phosphate, 0.8% Tryptone (Difco), 0.2% Soytone (Difco) and 1% casein hydrolyzate (Amber). The seed inoculum also can be grown according to the procedure set forth in U.S. Pat. No. 3,834,988. The seed inoculum is added to a growth medium which contains molasses, corn steep liquor from which the sludge has been removed, an inorganic nitrogen salt, other salts, water, and an anti-foaming agent. The medium is at a pH of about 7. The molasses can be cane molasses, beet molasses, or mixtures of cane and beet molasses, but beet molasses is preferred. MEDIUM COMPOSITION The medium can contain 2% to 8% beet molasses, about 0.6% to 4% corn steep liquor, and 0.1% to 0.6% sodium nitrate. The remainder of the medium is water. A specific preferred medium composition is composed of 3% beet molasses, 1% corn steep liquor, 0.2% NaNO 3 , 0.025% MgSO 4 .sup.. 7 H 2 O, 0.1% K 2 HPO 4 , 0.025% KCl, 0.001% FeSO 4 .sup.. 7 H 2 O, and 0.06% Dow Corning Antifoam A (10% solid). The sludge of corn steep liquor is first removed by filtration or centrifugation after mixing with molasses and adjusting the pH to 7.1 with NaOH. The corn steep liquor can be filtered alone. Other solids are added to compensate for variations in the compositions of the products which are the main constituents of the medium. The fermenter is sterilized for 60 minutes at 121° C. Growth is started by adding 4% inoculum to the medium in the fermentation. Aeration and agitation are set at 8 liters per minute or 0.8 vvm and 200-300 rpm, respectively. Temperature is set at 28° C. DETERMINATION OF GLUCOSE ISOMERASE ACTIVITY The cells are collected by centrifuging 30 ml. of the culture at 10,000 x g for 10 minutes. The cells are washed once with tap water, and sonified at 4° C. for 4 minutes in a Branson Sonifier J-17A after suspending in 14 ml. of 0.12 M phosphate buffer (pH 7.0). The cell-free extract is obtained by centrifugation at 27,000 x g for 15 minutes and used as a source of glucose isomerizing enzyme. The activity of glucose isomerase is determined as follows: to 3.0 ml. of assay solutions composed of 2.0 M glucose, 0.004 M MgSO 4 and 0.0004 M CoSO 4 is added a crude enzyme solution in 0.12 M phosphate buffer of pH 7.0 to a final volume of 4.0 ml. The reaction is carried out at 75° C. Aliquots are taken at 10, 15, 20 and 25 minutes and diluted in 0.02 M HCl. The fructose content of the samples is assayed in an automatic analyzer by adapting the skatole-HCl method described by Pogell. The color development is carried out at 52° C. as opposed to 37° C. Activity of glucose isomerizing enzyme is calculated from the slope and expressed in units (u). A unit of activity is defined as that quantity of enzyme which will produce 1 micromole of fructose from the glucose in 1 minute at 75° C. Following in Table I is a comparison of the production of glucose isomerase cells from this medium which contains beet molasses and corn steep liquor with a medium containing only corn steep liquor. From Table I, it is apparent that BM-CSL medium is superior to CSL medium with respect to the production of glucose isomerase by the said organism. TABLE I______________________________________Comparison of Glucose Isomerase Production Between CellsGrowing in Corn Steep Liquor Medium (CSL) and Cells Growingin Beet Molasses-Corn Steep Liquor Medium (BM-CSL).______________________________________ Production of Enzyme (μ/ml. culture)*Growth Cells Grown in Cells Grown inPeriods (hr.) CSL Medium** BM-CSL Medium______________________________________24 2.5 9.636 -- 23.248 8.7 39.060 16.7 50.572 20.9 51.0______________________________________ *pH of cultures was not controlled **CSL medium contained 4% corn steep liquor supplemented with 0.1 mM Co++ and 0.05 mM Cu+ Table II which follows shows that removal of sludges from corn steep liquor is essential to the production of glucose isomerase from Actinoplanes missouriensis. It also shows that a molasses medium will support growth of the organism to produce glucose isomerase, but that the combination of molasses and corn steep liquor greatly increases the production of isomerase. TABLE II______________________________________Effect Of Corn Steep Liquor Sludge On The Production OfGlucose Isomerase From Actinoplanes Missouriensis (ShakerGrown Cells)______________________________________ Production of EnzymeMedia (μ/ml.) culture______________________________________Molasses medium (nocorn steep liquor) 17.9Molasses and corn steepliquor* (sludges havenot been removed) 0 (no growth)Molasses and corn steepliquor* (sludges have beenremoved) 32.0______________________________________ *Molasses: 3.2%; Corn steep liquor: 1.0%. Grown for 4 days. As mentioned, the optimal concentration of beet molasses for production of glucose isomerase is between about 2% to about 8%. The preferred concentration is about 3%. The production of enzyme decreases sharply in the presence of more than 10% molasses. Table III which follows demonstrates these data. The media contained 1.5% corn steep liquor except for Run 5. The amounts of beet molasses varied as indicated. The rest of the media were as set forth hereinbefore under `Medium Composition`. TABLE III__________________________________________________________________________Effect of Beet Molasses Concentrations on the Production of GlucoseIsomeraseGrowth PeriodsEnzymeProduction % Beet Molasses In Each Fermentation Run.sup.1 and Run-1 Run-2 Run-3 Run-4 Run-5 Run-6 Run-7 Run-8 Run-9 Run-10hrs. Growth 0 1.0 2.0 3.0 3.0 4.0 5.0 6.0 8.0 10.0__________________________________________________________________________24 Activity.sup.2 ND.sup.4 ND ND 11.0 7.1 15.4 12.2 7.8 16.9 ND Growth.sup.3 ND ND ND 1.3 0.6 1.6 1.5 1.0 1.2 ND36 Activity ND ND 9.8 33.3 15.1 -- 24.4 23.0 21.1 6.2 Growth ND ND 1.1 3.1 1.4 -- 2.6 2.1 2.3 0.848 Activity ND ND 26.7 47.3 24.1 35.7 35.9 27.4 32.2 9.2 Growth ND ND 2.9 3.5 1.8 3.0 3.2 2.5 3.1 1.360 Activity ND ND 48.4 59.2 28.6 57.3 50.3 41.3 44.1 12.3 Growth ND ND 3.6 3.7 2.3 3.8 4.2 3.6 3.6 1.672 Activity 15.1 19.6 56.7 63.8 25.8 66.5 68.2 45.8 50.9 14.0 Growth 0.8 1.2 3.3 3.5 2.3 4.3 4.9 4.0 3.9 1.784 Activity -- -- 62.0 -- 32.4 78.8 63.0 60.2 61.1 10.8 Growth -- -- 3.0 -- 2.5 4.4 5.10 4.20 4.2 1.796 Activity 16.3 33.4 69.2 -- 31.4 74.1 59.0 62.2 62.9 13.9 Growth 0.7 1.8 3.2 -- 2.7 4.3 4.9 5.3 4.4 1.6__________________________________________________________________________ .sup.1 All fermentation runs contained 1.5% corn steep liquor except Run- in which CSL was omitted. .sup.2 μ/ml culture .sup.3 mg extractable protein/ml culture .sup.4 not determined due to poor growth Table III shows that in the absence of beet molasses, the production of enzyme in the 72 hour old culture is only 24% of that obtained from the medium containing 3% molasses but the specific activity of enzyme from both media are almost the same (see Run-1 and Run-4 in Table III). In the absence of corn steep liquor, the production of enzyme from the medium containing 3% molasses is only 41% of that containing 1.5% corn steep liquor in addition to 3% molasses, but the specific activity of the former enzyme preparation is only 62% of the latter (see Run-5 in Table II). This result indicates that the corn steep liquor promotes the production of enzyme, whereas molasses stimulates the growth of the organism. Combinations of both molasses and corn steep liquor therefore increase the yields of the enzyme. The amount of corn steep liquor that can be used is from about 0.6% to about 4.0%. Above 4% the growth may be poor depending on the quality of corn steep liquor. It preferably is about 1.5% as shown in Table IV which follows: TABLE IV______________________________________Effect Of Corn Steep Liquor (CSL) Concentration On TheProduction Of Glucose Isomerase In The Beet Molasses Medium*(Fermentor Grown Cells 60 Hours Old)Concentration of CSL Production of Enzyme (μ/ml. culture)______________________________________0 28.60.6 29.01.0 44.01.5 59.5______________________________________ *The composition of this medium has been described hereinbefore under `Medium Composition`. Cane molasses, beet molasses and mixtures of cane and beet molasses can be used to produce glucose isomerase. This is illustrated as follows: Actinoplanes missouriensis is cultured in 100 ml. of medium of 3% cane molasses, 1.5% desludged corn steep liquor mixture at a pH of 7.1 supplemented with minerals as hereinbefore described. The culture is grown in 250 ml. Erlenmeyer flasks on a rotary shaker at 28° C. for 4 days. The enzyme yields are then determined. The results are set forth in Table V. TABLE V______________________________________Molasses % Enzyme Yields (μ/ml. culture)______________________________________Cane 3% 29.7Beet 3% 39.2Cane andbeet 1.5% each 34.6______________________________________ From the foregoing Table V, it is apparent that cane molasses can also be used to produce glucose isomerase. Inorganic nitrogen salts, as well as urea, also are effective in increasing enzyme production by a factor of 48% to 128%. In preparing the following Table VI, Actinoplanes missouriensis is grown in 100 ml. of filtrate of 3% beet molasses, 1.5% corn steep liquor mixture (pH 7.1), supplemented with minerals as previously described. The filtrate is placed in 250 ml. Erlenmeyer flasks and sufficient amounts of inorganic nitrogen salts such as NaNO 3 , NH 4 NO 3 , (NH 4 ) 2 SO 4 , NH 4 H 2 PO 4 , NaNO 2 , and urea are added to the medium to give a final concentration of 5.9 mM of nitrogen atom. After sterilization, the medium is inoculated, the flasks are placed on a rotary shaker, and the organism is grown in the flasks for 4 days at 28° C. If NaNO 3 is the nitrogen salt, from about 0.1% to about 0.6% is used. Other nitrate salts can be used which give equivalent amounts of nitrate. The other nitrogen salts are used in amounts effective to give nitrogen equivalent to that in from 0.1% to 0.6% NaNO 3 . TABLE VI______________________________________EffectOf Inorganic Nitrogen Salts And Urea On The ProductionOf Glucose Isomerase Of Actinoplanes missouriensisInorganic Nitrogen Salts Enzyme Production μ/ml. culture______________________________________None 19.4NaNO.sub.3 32.5NaNO.sub.2 28.6(NH.sub.4).sub.2 SO.sub.4 44.0NH.sub.4 NO.sub.3 37.8NH.sub.4 H.sub.2 PO.sub.4 34.7Urea 33.3______________________________________

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This application is a continuation, of application Ser. No. 07/958,713 filed Oct. 9, 1992, now abandoned. The invention relates to artificial standard and control reagents for use in immunochemical detection methods and to processes for the preparation of these reagents. BACKGROUND OF THE INVENTION Customary immunological methods for diagnosing diseases associated with production of specific antibodies against any pathogen such as viruses, bacteria, allergens, autoantigens or certain pharmaceuticals are based on the ability of these antibodies to form complexes with antigenic structures on the causative agent. In some of these methods, a sample whose content of specific antibodies is to be tested is contacted with the antigenic structures of the pathogen, these antigenic structures being attached to suitable carrier materials. Specific antibodies which are present in the sample are bound and detected as immune complex with the antigenic structures of the pathogen which are immobilized on the carrier material. It is possible to use for this antibodies or other receptors, for example protein A, which are able to form complexes with the specific antibody in the sample. As a rule, the detection reagent carries a label which makes it possible to establish the amount of the bound specific antibody by measurement techniques. Commonly used labels are: radioactive isotopes, enzymes, fluorescent, phosphorescent or luminescent substances, substances with stable, unpaired electrons, erythrocytes, latex particles, metal sols. Control and standard sera which contain a defined quantity of the antibodies to be detected are required for these immunochemical methods. A positive control serum of this type makes it possible to test the utilizability of the reagents used in the assay. Standardization and thus comparability of assay results which have been obtained on different days or in different laboratories additionally become possible. Quantitative determinations are possible with the aid of standard sera. A technique which is frequently practized for the preparation of positive control or standard sera comprises taking blood from patients whose disease is caused by defined causative agents, obtaining the serum, and adjusting the control or standard serum to a particular content of specific antibodies directed against the pathogen by mixing sera from different patients. The disadvantages of this method are that a sufficient number of people whose blood contains these antibodies must be available. Furthermore, there are often medical reasons for not taking blood from such people, for example in the case of children, or there is a risk that the blood of the patient is infectious and no suitable methods for killing this pathogen are known. DESCRIPTION OF THE RELATED ART DE-A-31 12 334 describes artificial standard and control sera and processes for the preparation thereof and the use thereof, which do not have the abovementioned disadvantages. The standard and control reagent used is a chemically linked conjugate of two components A and B, where component A in the conjugate confers the ability to form complexes with the antigenic structures in the pathogen, and component B represents a human immunoglobulin or immunoglobulin fragment of that class which is to be measured in the immunochemical detection method. Thus, in order to prepare a conjugate as claimed in DE-A-31 12 334, it is necessary to isolate component B, i.e. human immunoglobulin of class G, M, A, D or E, in large quantity and in extremely high purity from human serum. An identical procedure for preparing artificial standard and control reagents is described in 1988 in DE-A-38 00 048. The disadvantages of these processes are that an elaborate purification process is necessary to obtain the immunoglobulins, and this purification procedure leads to loss of or alteration in antigenic structures of the immunoglobulins. Thus, for example, human immunoglobulin M is prone to aggregate formation in all known purification processes, which impairs its utility for the preparation of conjugates of the type described above. In the case of other immunoglobulins, for example of the IgE class, the concentrations normally occurring in human sera are below 100 μg/l. To purify human IgE it is therefore necessary to have recourse to blood donated by myeloma IgE patients, of whom only a few are known worldwide, and whose blood samples are correspondingly rare and costly. SUMMARY OF THE INVENTION Control sera within the meaning of this invention also include standard sera. The object therefore was to find artificial standard and control sera which do not have the disadvantages of the conjugates described above. Surprisingly, it has been found that a suitable artificial standard and control serum can be obtained by preparing a conjugate of a component A which represents a binding factor for structural features of the pathogen, such as, for example, an antibody directed against this structural feature, and of a component B which is able to bind to specific structural features of the binding factor to be detected, which is directed against the pathogen, without restricting the immunochemical reactivity thereof. This conjugate is added in a suitable concentration to blood, blood components or sample fluid from healthy individuals. The resulting product is then employed for standard or control purposes. It has emerged that conjugates of the components A and B just described can be prepared reproducibly, and a reagent with excellent suitability for checking function or for standardization can be obtained in conjunction with the natural content of immunoglobulins in the blood, in blood components or other sample fluids from non-patients. The invention thus relates to standard and control sera for use in immunochemical detection methods for antibodies of particular antibody classes in body fluids from mammals, these antibodies being specifically directed against particular pathogens, characterized in that these standards and control sera contain conjugates of an analyte-specific and of an antibody-specific binding portion in the presence of the specific antibody class which is to be detected in the mammal, where the conjugate as such is not recognized as immunochemical equivalent to the antibody to be detected. FIG. 1A depicts the prior art and FIGS. 1B and 1C depict embodiments of the claimed invention. The figures are illustrative and are not intended to limit the present invention. BRIEF DESCRIPTION OF THE DRAWING FIG. 1. Comparison of prior art positive control with an artificial positive control. FIG. 1A shows a prior art immunoassay to detect antibodies that are specific for a particular pathogen and are of a specific immunoglobulin (Ig) class. Pathogen-specific antibodies of a particular Ig-class (the analyte), if present, bind to pathogen that is bound to a solid phase. The bound pathogen-specific antibodies are detected using a labeled antibody that is specific for the immunoglobulin class of the analyte. In the illustrated embodiment, the label is an enzyme (Enz) conjugated to the antibody. The positive control is a pathogen-specific antibody of the immunoglobulin class that is to be measured. FIG. 1B shows an artificial positive control. A bifunctional conjugate binds specifically to the pathogen, and also binds to immunoglobulins of the class to be assayed. The immunoglobulins that bind to the bifunctional conjugate need not be specific for the pathogen. The artificial positive control bound to the solid phase is detected by a labelled antibody specific against the immunoglobulin class that is bound to the bifunctional conjugate. FIG. 1C is similar to FIG. 1B, but shows that the bifunctional conjugate comprises two components. The component which binds to the pathogen (component A) is an antibody that is specific for the pathogen. Component A is linked to a second component (component B) which is an antibody directed against immunoglobulins of the immunoglobulin class be detected in the assay. The "artificial positive control" comprises the bifunctional conjugate and bound immunoglobulins of the class to be detected. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred standard or control sera in this connection are those in which the antibodies to be detected are of human origin. Further preferred standard or control sera are those in which the analyte-specific and antibody class-specific binding portions are monoclonal antibodies or antibody fragments. Structural features of the pathogen are antigens, for example proteins, glycoproteins. It is possible and preferred for component A of the conjugate to be formed by polyclonal or monoclonal antibodies or fragments thereof, which can be prepared against structural features of the pathogen by processes known to the person skilled in the art, as well as lectins or other receptors. Component A is preferably of non-human origin. Non-human within the meaning of this invention means that the molecule identified as such is not recognized as such by specific binding partners which are employed for detecting the analyte antibodies. Monoclonal antibodies are particularly preferred. Component B is preferably likewise composed of polyclonal or monoclonal antibodies, or fragments thereof, which are directed against the antibody to be detected, or of binding factors, for example lectins or protein A, which are able to react specifically with structural features of the antibody to be detected. Antibodies are particularly preferred, and monoclonal antibodies are very particularly preferred. Component B is preferably also of non-human origin. A conjugate within the meaning of the invention means any construct in which components A and B are linked while retaining their immunochemical function. Methods familiar to the person skilled in the art for preparing such conjugates are, for example, linkage by chemical reagents or by bioaffinity interaction. It is, however, also possible to produce hybrid molecules by chemical synthesis, the hybridoma technique or genetic engineering methods. Antibodies within the meaning of this invention also include the antibody fragments which are relevant in each case and are known per se to the person skilled in the art. A typical process for preparing the sera according to the invention appears is as follows: Monoclonal antibodies against an analyte antigen are prepared by processes known to the person skilled in the art. The analyte-specific antibodies are linked by the process described in Example 1 to monoclonal antibodies which are specifically directed against the antibody class to be detected. The conjugate is purified, for example, by gel chromatography. It is advantageous for the conjugate subsequently to be concentrated, for example by dialysis, preferably to 1 to 10 mg/ml, and to be stabilized by methods known to the person skilled in the art. Defined amounts of this conjugate are added to a particular volume, for example of a normal human serum free of analyte antibodies. This standard or control serum obtained in this way can be stabilized and rendered storable in a way known to the person skilled in the art. The serum is employed for use in the way known to the person skilled in the art. The process according to the invention is characterized by its universal applicability. No restrictions which would impair application of the processes used in the examples to other conjugates are known. The process according to the invention can also be applied to non-human control sera, it being essential that the conjugate which is employed is not recognized as such by the molecule employed as labeling receptor in the relevant assay method but is recognized only after binding to a molecule specific for the particular animal species and antibody class. The standard and control sera according to the invention can be used in a large number of human and veterinary diagnostic methods. Examples to be mentioned are detection of antibodies of various immunoglobulin classes against structural features of viruses, for example viruses of hepatitis A, B, C, various HIV types, of rubella, cytomegaly, measles, mumps, varicella, herpes simplex and Epstein-Barr virus, of bacterial and parasitic pathogens, such as syphilis, borreliosis, toxoplasmosis, and of allergic disorders, for example the detection of allergy-specific IgE antibodies, of autoimmune diseases, and the detection of humoral defense reactions in patients who have possibly received administration of immunogenic agents for diagnostic or therapeutic purposes. Examples thereof are monoclonal antibodies against tumor-associated structures, and recombinant proteins with cytokine-like or coagulant properties. The invention is illustrated by the following examples: EXAMPLE 1 Preparation of a Positive Control Serum for Anti-HBcAg IgM 1 ml of 0.2M Li BO 3 /20% dioxane is added to 4 mg of monoclonal anti-HBcAg antibody (in 1 ml of PBS pH 7.2), and a 15-fold molar excess of N-γ-maleimidobutyryloxysuccinimide (GMBS) is added, and the mixture is incubated at room temperature for 1 h. The unreacted heterobifunctional reagent is removed by gel chromatography (SEPHADEX G-25, a treated gel prepared by cross-linking dextran with epichlorohydrin under alkaline conditions) with 0.1 molar sodium phosphate buffer+5 mM nitrilotriacetic acid (NTA) pH 6.0. 2 mg of monoclonal anti-human IgM antibodies (in 2 ml of 10 mM sodium phosphate, 100 mM NaCl, pH 7.4) are incubated with a 24-fold molar excess of N-succinimidyl 3-(2-pyridyldithio)propionate (SPDP) at room temperature for 30 minutes and then reduced with a 100-fold molar excess (compared with SPDP) of dithiothreitol (DTT) at RT for 15 minutes. After the reduction has taken place, the excess of reagents is removed by gel chromatography (SEPHADEX G-25) with 0.1M sodium phosphate/5 mM NTA pH 6.0. The SH-activated anti-human IgM is incubated with the activated anti-HBcAg at RT for 2 hours and subsequently stopped with 1/10 the volume of 0.1M N-ethylmaleimide. The conjugate is purified by gel chromatography (ACA 34, LKB) with 50 mM Tris/HCl pH 7.4, and subsequently concentrated to 3 ml and stabilized with HSA. 50 μl, 25 μl, 12.5 μl and 6.25 μl of this conjugate (concentration=2 mg/ml) are pipetted into 1 ml of normal human serum (anti-HBc IgM negative), filtered through 0.2 μm Sartorius membrane filters and stored at +2° to +8° C. EXAMPLE 2 Use of the Conjugates in an Enzyme Immunoassay In an enzyme immunoassay to detect IgM antibodies against HBcAg ENZYGNOST, an ELISA-type immunoassay (enzyme-linked immunosorbent assay) anti-HBcAg/IgM assay kit of Behringwerke AG, Marburg, FRG), 10 μl of a serum which has previously been diluted 1:100, or of the artifical positive control prepared as in Example 1, and 90 μl of sample buffer are incubated in microtiter plates coated with anti-human IgM at 37° C. for one hour, washed in accordance with the package insert, incubated with 100 μl of HBcAg-POD conjugate at 37° C. for one hour, washed again, incubated with 100 μl of tetramethylbenzidine (TMB) substrate solution in accordance with the package insert at room temperature for 30 min, stopped with 100 μl of 0.5M H 2 SO 4 solution, and measured in a photometer at 450 nm. The peroxidase marker enzyme catalyzes the conversion of the chromogan TMB into the dye; the color produced after 30 minutes is proportional to the content of antibodies directed against HBcAg in the sample. The extinctions obtained for the artificial positive control in the serial dilutions described in Example 1 are compared with the extinction for the negative control in Table 1: TABLE 1 TABLE 1______________________________________Dilution of the Extinctions of theartificial pos. Extinctions neg. controlcontrol at 450 nm at 450 nm______________________________________1:20 >3.0001:40 2.583 0.0561:80 1.385 1:160 0.638______________________________________ EXAMPLE 3 Preparation of a Conjugate of Anti-human IgM and of an Anti-Herpes Simplex Virus (HSV) F(ab') Fragment 10 mg of monoclonal antibodies against HSV (in 2 ml of 50 mM sodium acetate buffer pH 4.3) are incubated with 1 mg of pepsin at 37° C. for 24 h, and the reaction mixture is adjusted to pH 7.2 with about 0.2 ml of 2N NaOH. The F(ab') 2 fragment is purified by gel chromatography (ACA-44 supplied by LKB) with 50 mM Tris/HCl pH 7.4, and subsequently concentrated to 1 ml (about 5 mg of F(ab') 2 fragment) and reduced to F(ab') with 0.1 ml of 0.1M cysteamine HCl solution at RT for 60 minutes and subsequently chromatographed on SEPHADEX G-25 (column 1 cm vol. 10 ml). The reduced anti-HSV F(ab') fragment is reacted with 5 mg of activated anti-human IgM-maleimide (see above) at 37° C. for 1 hour. Unreacted antibody F(ab') fragment is separated from the actual conjugate by gel chromatography (ACA-34 LKB) with 50 mM Tris/HCl pH 7.4, subsequently concentrated to 5 ml and stabilized with HSA. EXAMPLE 4 Anti-GM-CSF IgM Positive Control Sera An F(ab') fragment of a rabbit anti-GM-CSF antibody was conjugated to a mouse anti-human IgM antibody in analogy to Example 3.

4y

TECHNICAL FIELD The present invention relates to a materials handling device and above all to a materials handling device such that it consists of one or two parallel guides forming a transport track, along which an organ for gripping, taking hold of and/or stacking the material is so arranged as to be capable of being moved. The present invention has been produced principally as a means of providing a materials handling facility in conjunction with a silk screen printing machine in which the material handled is in the form of cards which have or which are intended for an application in the area of printed circuits. A more generalized embodiment of the invention is intended to provide a means of transporting a material from one position to one of two or more other positions or from one of two or more positions to yet another position. The present invention is designed principally to enable the intended material to be transported before being printed in a silk screen printing machine from one or more feeder stacks to a register position and/or a printing position in the machine. The invention is also intended to enable the printed material to be transported from a silk screen printing machine to one or more stacks of finished print. DESCRIPTION OF THE PRIOR ART Various materials handling devices have already been disclosed which are designed to enable the intended material to be transported before being printed in a silk screen printing machine from one or more feeder stacks to a register position or a printing position in a silk screen printing machine. Also previously disclosed is a materials handling device for printed material in a silk screen printing machine which enables the printed material to be transported from the silk screen printing machine to one or more stacks of finished print. The materials handling device for the feeder stack is usually designed in a special manner which will enable it to transport the material as required, whereas the materials handling device for the stack of finished print is usually designed in a special manner which will enable it to transport the material as required at that point. Also previously disclosed is a materials handling device of such a nature that it may be used for both the feeder stacks and the stacks of finished print in a silk screen printing machine. Finally, various types of materials handling devices for other applications have also been disclosed, said devices generally being of a design which corresponds directly to the shape of the material or to the function which is expected of the materials handling device. Reference is made to English Patent Specification 1 341 978 for the purpose of illustrating a previously disclosed materials handling device in which two limit switches are used. DESCRIPTION OF THE PRESENT INVENTION TECHNICAL PROBLEM A major technical problem has existed for some time now in connection with producing a materials handling device which is of such a nature that it is capable of providing efficient transport of the material without the need for it to be specially adapted to suit the surrounding equipment. It has been found to be particularly desirable, above all in the case of silk screen printing machines, to be able to provide an identical design of materials handling device both at the feeder stack of the silk screen printing machine and at the stack of finished print of the silk screen printing machine. It is particularly desirable in a complete silk screen printing plant consisting of feeder stacks, a silk screen printing machine, a conveyor belt, a drier and a further conveyor belt, to be able in a simple manner to provide a single materials handling device which is capable of transferring material from one conveyor to another conveyor running parallel to it, or to another conveyor running at right-angles to it and/or to and from the silk screen printing machine. It is possible for faults to occur in certain areas of a large silk screen printing plant, and in order that the entire plant need not be stopped it is particularly desirable to provide a materials handling device of such a kind that it is not only capable of transporting the material in the manner required by the entire plant, but is also capable of satisfying a desire and of solving a problem, i.e. by providing a materials handling device of such a nature that, in the event of a fault occurring in any part of the entire plant, the said materials handling device will be capable of transporting the material to a buffer store until the fault has been corrected. The materials handling device shall then be capable of removing the material from the buffer store and of placing said material on the production line of the entire silk screen printing plant. Where several, for instance six, silk screen printing plants are being run simultaneously, it has proved difficult to position the various feeder stacks effectively in such a manner that as one feeder stack becomes empty a new one may be introduced rapidly in its place. It represents a major technical problem to position two feeder stacks adjacent to each other and to arrange for an organ which will take hold of and stack the material either to take a sheet of material first from one feeder stack and then from a second feeder stack, or for the organ to take material from the first feeder stack until that stack becomes empty and then to proceed to take material from a second feeder stack. It has also been found to be the case in certain specific applications that provision must be made for the track upon which the material is conveyed to adopt an inclined attitude so that the material may be transported to different levels in the machine. A problem has also been encountered in arranging for the track upon which the material is conveyed to take hold of material in a vertical or almost vertical attitude and then to transport and stack the material in a horizontal attitude. SOLUTION The aim of the present invention is to provide details of a materials handling device of such a nature that it is able to solve the aforementioned complex technical problems, and where the materials handling device in accordance with the present invention is based on the principle of arranging an organ for taking hold of and stacking a sheet of material in such a way as to be capable of being moved along a transport track, preferably in the form of a system of parallel guides. The invention is based on the assumption that three or more limit switches will be arranged along the transport track, for instance alongside the system of guides, for the purpose of defining three or more stop positions for the organ. At least two of the limit switches may be moved along the transport track so as to enable at least two of the stop positions to be changed independently of each other. The movement of the organ together with instructions for the operation to be performed at the stop position and any subsequent movement and subsequent instructions for the operation to be performed at the following stop position shall be capable of being entered as desired into a programming arrangement. The present invention includes details of a programming arrangement of simple design incorporating a number of manually adjustable knobs. Each knob has settings corresponding to the number of stop positions, and the number of knobs is greater by one than the number of stop positions. By means of the aforementioned programming arrangement the setting of each knob is able to indicate both the stop position and the operation to be performed, and the programming arrangement is so arranged that it will sense the setting of each knob in turn and will activate control signals corresponding to the setting. By allocating a consecutive sequence to the knobs, it is possible to use knobs to which uneven numbers have been allocated for operations concerned with taking hold of the material, whereas knobs to which even numbers have been allocated may be used for operations concerned with the stacking of the material, or vice versa, which means that the position of the knob is of significance to the operation which the organ is to perform. The present invention also includes details of the possibility of eliminating the limit switches, i.e. the outer movable organs, as a means of defining the stop positions of the organ. The control of the distance over which the organ is moved or of the distance which must be covered in order to move the material from one position to a second position is determined by an organ which senses the movement or the length of the movement. This sensing organ is connected to a central control device (incorporating a counting device). The equipment is designed in such a way that, at a pre-determined setting corresponding to or essentially corresponding to the distance covered by the organ between the first position and the second position, it will generate an activating signal, said activating signal causing the organ to stop, preferably by means of the driving device, once the material has reached the second position. The central control device may be programmed in such a way that the organ will stop at any desired position, where it will then perform one of the operations "grip the material" or "stack the material", whereupon it will cause the organ to move to a new pre-programmed position. ADVANTAGES The advantages exhibited by a materials handling device in accordance with the present invention are mainly associated with the fact that it has succeeded in solving the technical problems indicated above. The materials handling device in accordance with the present invention has also proved capable of being manufactured as a unit which is light in weight and which may be placed in any desired position on the production line, either for the purpose of feeding material from the feeder stack to the silk screen printing machine or for the purpose of feeding printed material from the silk screen printing machine to the stacks of finished print, or for the purpose of transferring material from one conveyor to a second conveyor running parallel to and adjacent to the first conveyor, or for the purpose of transferring material from one conveyor to another conveyor running at right-angles to it. The materials handling device may also be placed in any desired position on the production line so that it will fill a buffer store in the event of a temporary fault and will then take material from the buffer store once the fault has been corrected and will place said material on the production line. DESCRIPTION OF THE DRAWINGS A proposed embodiment of a materials handling device in accordance with the present invention will now be described with reference to the attached drawings, in which FIG. 1 shows a perspective view of the materials handling device described as being in accordance with the present invention, in use in conjunction with a silk screen printing machine and with a feeder stack or with a stack of finished print; FIG. 2 shows the materials handling device in position in a production line for the purpose of transferring material to a buffer store in the event of temporary faults occurring; FIG. 3 shows a perspective view of an organ for taking hold of and stacking material; FIG. 4 shows an instrument panel which may be used in a materials handling device for the purpose of controlling a programming arrangement; FIG. 5 shows a wiring diagram for the programming arrangement; FIG. 6 shows the principle of an organ for determining the length of the movement working in conjunction with a central control device; and finally FIG. 7 shows one other embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention relates to a materials handling device which incorporates a transport track consisting of a system of parallel guides, with an organ for taking hold of and stacking the material being arranged so as to be capable of being moved along said system of guides. The materials handling device may be used in a variety of different applications, and FIG. 1 shows how the materials handling device may be used in conjunction with a silk screen printing machine, not all of which appears in the Figure. FIG. 1 shows the manner in which the materials handling device is to be used for transporting material 1 from an initial feeder stack 2 to a register position 3 in a silk screen printing machine 4. The materials handling device 5 shall also be capable of transporting material 6 from a second feeder stack 7 to the register position 3 of the silk screen printing machine 4. The direction in which the material 1 and 6 passes along the production line is shown by the arrow "Pa". However, the materials handling device 5 may also be used for transporting material in the direction "Pb", when it will serve as a material conveyor from the output side of a silk screen printing machine 4 to one of several finished print stacks 2 and 7, in which material 1 and 6 which has been printed is stacked. The materials handling device 5 consists of a system of parallel guides 10, 11, along which an organ 12 for taking hold of and for stacking the material is so arranged as to be capable of being moved. The organ 12 is moved along the system of guides 10, 11 by means of a motor 13, and a beam 20 is guided by grooves in the parts 10 and 11 of the system of guides. Three or more limit switches identified as "A", "B" and "C" are arranged on the system of guides 10, 11, more specifically on the part 11. These limit switches are intended to define three or more stop positions for the organ 12. At least two of the limit switches may be easily moved along the system of guides 11, thus enabling at least two of the stop positions to be easily changed independently of each other. The limit switches may be moved easily in grooves formed in the part 11 of the system of guides. The limit switch may incorporate a Reed switch which is activated by a permanent magnet (not shown here) attached to the organ 12. The movement of the organ 12 which is produced by the motor 13, together with instructions for the operation which is to be performed at the respective stop positions as well as any subsequent movement and any subsequent instructions or operation which is to be performed at the following stop position may be entered as desired into a programming arrangement. This facility for infinite adjustment offered by the programming arrangement thus enables the materials handling device to be completely flexible and not dependent upon the manner in which the materials handling device has been installed in the product line or upon the direction in which the material is conveyed along the production line. FIG. 2 shows a conveyor 14 of which the direction of transport is indicated by the arrow "Pa" and where the production line is so designed that the material will be transported either in the direction of the arrow "Pc" or in the direction of the arrow "Pd". By arranging a materials handling device 5 in accordance with the present invention, the organ 12 is able to cause a sheet of material 1' to be transported by the conveyor in the direction "Pc", or else the organ 12 may take the sheet of material 1' and transfer it to the conveyor which will cause the material 1' to move in the direction of the arrow "Pd". In the event of a temporary interruption to the direction of movement identified as "Pc" or "Pd" the materials handling device 5 may take the material 1' intended to be moved in the direction "Pc" or "Pd" and may place said material in a buffer store 15. As soon as the fault has been corrected the materials handling device may then take the material from the buffer store 15 and place said material on the conveyor so that it will be transported in the direction "Pc" or "Pd". FIG. 3 shows, on a rather larger scale than in FIG. 1, the organ which takes hold of and stacks the material. This organ is held by a beam 20 which operates in conjunction with the guides 10 and 11. The beam 20 supports two other beams 21 and 22 which lie at right-angles to it, each of the said beams 21 and 22 supporting two pneumatically operated holding devices, of which only one is shown in FIG. 3 and is identified with the reference 23. By means of a rod 24 which may be moved both upwards and downwards, to the free end of which is fitted a suction disc 25, the rod may be extended downwards and the disc 25 will attach itself by suction to a sheet of material 1' and will then lift the material from the conveyor, whereupon it will transfer the material to a new stop position. By releasing the suction disc in the new stop position the material 1' may be stacked in that position. The organ 12 may be fitted with a device for indicating the presence of a sheet of material which will generate an output signal and activate the programming arrangement. FIG. 4 shows the front panel of a programming arrangement. Of the knobs on the front panel, the knobs "a", "b", "c" and "d" are of special interest, said knobs being manually adjustable. Each knob has settings corresponding to the number of stop positions, and in view of the three limit switches A, B and C shown in FIG. 1 each of these knobs has three different settings. The number of knobs shall be greater by one than the number of stop positions. The setting of each knob indicates the stop position and the operation which is to be performed, and the programming arrangement is so arranged that it will sense the setting of each knob in turn from "a" to "d" and will activate the control signals corresponding to the setting. The knobs have been allocated a consecutive sequence, and knobs which have been allocated uneven numbers are intended for operations concerned with taking hold of the material, whereas knobs which have been allocated even numbers are intended for operations concerned with the stacking of the material, or vice versa. The principle of the programming arrangement may be described in greater detail with reference to FIG. 1. On the assumption that the organ 12 will take material from the first feeder stack 2, the knob "a" is turned to the setting "B". This means that the organ 12 will stop above the feeder stack 2 and will pick up and hold the material 1. The programming arrangement will then index to the setting for the knob "b", where it will find the setting "C", which means that the organ 12 will move against the limit switch "C" and will release or stack the material 1 in position 3. The programming arrangement will then scan the setting of the knob "c", which means that the organ 12 will move to the limit switch "B" and will take the next sheet of material from the feeder stack 2. Finally, the programming arrangement will scan the setting of the knob "d" and will find that the organ 12 is to be moved to the limit switch "C" and is to stack the material in position 3 in the silk screen printing machine. The programming arrangement will then recommence the cycle, starting at the setting of the knob "a". The material in the feeder stack 2 will run out, however, and by indicating this fact (by means of a device which is not shown here) and feeding that signal into the programming arrangement by means of a knob "e" it is possible to re-programme the knobs "a" and "c" automatically so that these knobs will return to the position "A", thereby causing the organ 12 to take material 6 from the second feeder stack 7. The knob "e" is used to indicate automatic change-over of feeder stack. FIG. 5 shows a wiring diagram for the programming arrangement, from which only the principal control circuitry of the programming arrangement is evident. The programming arrangement 30 incorporates a control unit 31 to which a start signal is connected via a lead 32. When the start signal appears in the lead 32 the control unit 31 will scan the setting of the knob "a" and will generate an output signal in the lead 33 which will cause the motor 13 to move the organ 12 to position "B". When the signal appears in the lead 34 from the limit switch "B" the signal in the lead 33 will cease and the organ 12 will stop. The control unit is pre-programmed in such a way that the scanning of the knob "a" will generate an output signal in the lead 35, after the signal in the lead 34, which will cause the holding organ 23 to take hold of a sheet of material. The control unit 31 will now index forward and will scan the knob "b" and will generate an output signal in the lead 33 in order to move the organ 12 to position "C". When a signal appears in the lead 36 from the limit switch "C" the signal in the lead 33 will cease and the organ 12 will stop. The control unit is pre-programmed in such a way that the scanning of the knob "b" will generate an output signal in the lead 37, after the signal in the lead 36, which will cause the holding organ 23 to stack the material. The automatic re-programming of one or more knobs will take place when a signal appears in the lead 38, which is illustrated in this embodiment by the fact that the setting "B" for the knobs "a" and "c" will be changed to the setting "A". The materials handling device shown here may also be used for transporting the material in an inclined attitude. There is nothing to prevent the beam 20 from being attached to its holding devices in the parts 10 and 11 of the guides in such a way that it is free to turn. Thus the guides may be set in an inclined attitude but the organ 12 will adopt a horizontal attitude. If the pivoting attachment of the beam 20 to the holding devices 20a is controlled by means of a pneumatic cylinder with its associated ram, then the organ 12 may be rotated so that it will take hold of vertically (or essentially vertcally) oriented material and will place the material on a horizontal conveyor. Finally, a compression device for the material may be arranged on the organ 12, which means that when the suction discs 25 take hold of the material the ends of said material will bend upwards and separate from the remaining material in the stack. Once the material has separated, the effect of the compression device will cease and the material will assume a flat condition once more. The motor 13 is in the form of a d.c. motor and can be controlled so as to cause the organ 12 to move at different speeds between the stop positions. FIG. 6 shows an embodiment in which the distance to be covered by the organ is determined by a distance-sensing organ which operates in conjunction with a central control unit. The use of this embodiment enables the outermost limit switch or unit for determining the stop position to be eliminated. Where there is a requirement to determine the distance to be covered by the material within close tolerances, from the first position to the second position, the present invention indicates that the movement of the organ 12 relative to the guides shall be measured by a movement-sensing organ 40. Said organ 40 shall operate in conjunction with the guides and shall be attached to the organ 12. Said movement-sensing organ 40 is in the form of an "optical shaft encoder", i.e. a device which will generate a coded output signal by means of an optical system. The device may be of the type OM25 marketed by Data Technology Inc., Mass. USA, which is designed to produce 2500 pulsations per revolution. The device in accordance with the present invention indicates that the shaft 41 has attached to it a wheel 42, with a toothed or grooved periphery 42a, and with the diameter of said wheel 42 being selected in such a way that one pulse will be generated in the lead 43 from the organ 40 for each small longtitudinal division. In the case of the preferred embodiment the diameter of the wheel has been selected in such a way that each pulse corresponds to a distance of travel of 0.1 mm by the organ 12. The lead 43 is connected to a counting device 44 of the type "Electronic Digital Preset Counter" as manufactured by NLS, Non Linear System Corp., Calif., USA, under the model designation PR-S. The wheel 42 makes contact with the guide 10 and is thus able to measure the distance covered by the organ 12 and the material from the first position to the second position. The lead 43 is thus connected to the electronic counter 44 which measures each small longtitudinal division. This counter may be set at a pre-determined value, said value then corresponding to the distance covered by the organ 12 from the first position to the second position, and when the counter reaches the pre-set value an activating signal will be generated via a lead 45. This activating signal is able to cause the driving device 46 in the form of a d.c. motor 13 to stop the driving motor and the organ 12 when the material has reached the second position. FIG. 7 shows one other embodiment. This device incorporates a position-sensing organ 50 which is equivalent to the counter 44. The position-sensing device 50 is controlled via the lead 43 and will indicate the position of the organ 12 along the guide 10 at any given point in time. Each small movement of the organ 12 will produce a corresponding change in the device 50. The embodiment of the invention shown in FIG. 7 incorporates a device 51 for selecting the sequence and the operation to be performed. The sequence and any desired operation may be programmed by means of this device in accordance with the setting of the device 50. Signals corresponding to the position of the device 50 are transmitted to the selector 51 via the lead 50a. The following are typical examples of programming of this kind: (a) move the organ 12 to a position in which the position-sensing organ indicates a setting of 1 000; (b) take a sheet of paper; (c) move the organ 12 to a position in which the position-sensing organ indicates a setting of 2 400; (d) stack the sheet of paper. When the sequence selector has given instructions via the lead 51a for the organ 12 to be moved to the position 1 000 the driving motor 46 (13) of the organ 12 will cause the organ 12 and the position-sensing organ 50 to move to the position 1 000, when the organ 12 will stop. This is achieved by the use of a reference circuit in the device 51, in which the pre-set value 1 000 is stored and into which the value produced by the organ 50 at any given point in time is fed. Where the values agree or essentially agree, a signal will be generated which will stop the organ 12 in the position 1 000. The sequence selector will now instruct the operation selector to generate a signal via the lead 51b which will cause a sheet of paper to be taken. The sequence selector will instruct the organ 12 to be moved to position 2 400 as indicated above and will finally instruct the sequence selector to stack the sheet of paper. The control device used in this embodiment may be in the form of the programme-controlled control unit known as the "SAIA PC" as manufactured by SODECO-SAIA AG of Murten, Switzerland. The invention is not, of course, restricted to the typical embodiment described above, but may undergo modifications within the scope of the idea of invention.

4y

This invention applies to an apparatus and method for metal turning in which the continuously formed chip is broken as it is formed. BACKGROUND OF THE INVENTION Metal turning basically involves rotating a metal workpiece while simultaneously moving a tool holder axially along the workpiece. The tool holder incorporates a cutter that is advanced radially relative to the surface of the workpiece so that a metal chip is continuously formed, which curls away from the workpiece, generally in a tight spiral. The cutter is advanced radially to the greatest degree possible, and the tool holder moved with the greatest axial feed possible, without creating excessive cutting forces. For any given radial advance and axial feed, the chip produced will have a predetermined and relatively constant radial width and axial thickness, both of which are relatively small. The length of the chip, however, will be potentially very great, as there is nothing to break it beyond its own weight, or contact with another object. For maximum efficiency in chip handling, it would be desirable to repeatedly break up the chip as it was formed. It is known in the art to repeatedly break the chip as it is formed with various apparatuses that vibrate the cutter axially back and forth relative to the tool holder as it moves. Known apparatuses that do this vibrate the cutter continually, creating a sinusoidal pattern relative to the circular surface of the workpiece, and so require that the vibration of the cutter be deliberately kept in an out-of-phase relationship to the rotation of the workpiece. If the two were not kept out-of-phase, the chips would not break up. Instead, long chips would continuously form that also had a wavy shape superimposed upon their length, but which would not break any more readily than a straight chip. There are several examples of patented apparatuses and methods designed to assure the necessary out-of-phase relation. SUMMARY OF THE INVENTION The invention provides a new method and apparatus to repeatedly break chips that does not rely on superimposing a continual, vibratory motion onto the axial feed of the cutter. There is no need to assure an out-of-phase relationship between the cutter vibration and workpiece rotation. In the preferred embodiment disclosed, a workpiece is rotated about its axis and a tool holder is moved axially along the rotating workpiece, just as in conventional turning. The tool holder includes a cutter support that is adapted to withdraw and return axially relative to the tool holder in incremental fashion when an axial force is applied to it. In the embodiment disclosed, the cutter support is in the nature of a cantilever beam that can be bent out away from the tool holder when forced, and which springs back when released. A conventional cutter bit fixed to the end of the cutter support is advanced radially relative to the workpiece, engaging its surface and producing a continuous chip as the tool holder moves. Rather than applying a vibratory force to the cutter support, a means is provided that applies an impulsive, rapidly applied and removed axial force. In the embodiment disclosed, this comprises a piezoelectric element, which is capable of rapid, though slight, expansion and contraction in response to a rapidly changing voltage, which is supplied by a controller. The controller keeps the voltage normally high, which keeps the piezoelectric element slightly expanded. The slight expansion is amplified by a master and slave piston assembly into an axial motion of the cutter support that is sufficient to keep the cutter support axially advanced and under tension relative to the tool holder as it cuts. When the voltage is rapidly dropped, the element contracts rapidly, and the cutter support and cutter rapidly withdraw from the cut. The same voltage is very quickly reapplied, causing the cutter to return to its original position and break the chip. The degree of incremental cutter withdrawal is designed to be comparable to the degree of axial cutter feed per workpiece revolution, assuring that the chip is cut. The pattern produced by the cutter relative to the workpiece surface is not sinusoidal. Instead, the motion is sharply changing and choppy, so there is no need to keep the cutter motion and workpiece rotation out of phase. The frequency of cutter withdrawal and advance may simply be set so as to break the chip into any desired length. It is, therefore, a general object of the invention to provide a metal turning chip breaking method that does not require keeping the cutter vibration and workpiece rotation out-of-phase. It is another object of the invention to break the chips by applying an impulsive force to the cutter to rapidly withdraw and return the cutter from and to the cut in an incremental fashion. It is another object of the invention to provide such an impulsive force through the use of a piezoelectric element that has a rapidly increasing and decreasing voltage applied to it. It is still another object of the invention to provide a means for amplifying the slight expansion and contraction of the element sufficiently to advance and withdraw the cutter sufficiently to break the chip. DESCRIPTION OF THE PREFERRED EMBODIMENT These and other objects and features of the invention will appear from the following written description, and from the drawings, in which: FIG. 1 is a perspective view of the known method of chip breaking described above; FIG. 2 is a graph depicting the out-of-phase relationship created by the known chip breaking method.; FIG. 3 is a partially schematic representation of a workpiece and the apparatus of the invention; FIG. 4 is a cross sectional view of the tool holder, cutter support, cutter and force application means; FIG. 5 is a graph depicting the chip breaking action provided by the invention. Referring first to FIG. 1, the known method of chip breaking described above is illustrated. A workpiece (10), which is cylindrical metal bar stock, is to be turned down from a rough, initial diameter to a final, finished diameter. To accomplish this, workpiece (10) is rotated about it's central axis by a standard lathe or the like, not illustrated, while a cutter (12) is moved parallel to the axis of workpiece (10). Before moving axially, cutter (12) is radially advanced to a point where it is radially inboard of the outer surface of workpiece (10), and so will engage its surface. Cutter (12) is adjusted and moved by a conventional tool holder, which is not illustrated, but well known to those skilled in the art. How far cutter (12) is advanced radially, how fast it is rotated, and how far it is fed axially per rotation depend on the cutter (12), the workpiece material, and the surface finish required. Basically, experience will tell how hard cutter (12) can be driven without causing excess cutting forces, chatter, or excessive tool wear, and this can be determined by one skilled in the art. Whatever the parameters of cutter (12)'s operation, it will continuously produce a chip (14) from workpiece (10), which curls out and away from cutter (12) as illustrated. Still referring to FIG. 1, the width of chip (14) corresponds to the radial advance of cutter (12), and its axial thickness corresponds to the axial feed per rotation, but it's length may vary considerably. In the absence of some mechanism to actively break it up, chip (14) could conceivably be as long as the entire linear surface seen by cutter (12) in each pass, especially with ductile materials. Illustrated is a known method of repeatedly breaking chip (14). The successive circular lines on the finished surface of workpiece (10) represent the path that would be followed by the point of cutter (12) if it had no axial vibration superimposed on its axial feed. This would leave the familiar threaded pattern that can be seen on many machined shafts. Instead, cutter (12) is vibrated back and forth in the axial direction as it advances, with an amplitude close to the degree of axial advance per revolution of workpiece (10). Cutter (12) vibrates constantly, that is, it is never still relative to it's tool holder. This constant vibration, coupled with the rotation of workpiece (10), causes cutter (12) to describe a sinuous wave pattern on the machined surface, as shown by the wavy lines. This superimposed vibration of cutter (12) will break the chips (14), but only if the vibration can be kept deliberately out-of-phase with the rotation. Referring next to FIG. 2, the out-of-phase relation is shown graphically. The X axis represents the axial vibration amplitude, Y represents distance along the surface of workpiece (10), X i and X i+1 represent successive rotations, and y represents the phase shift between them. A deliberate phase shift assures that peaks and valleys of successive cuts are nearly aligned. Thus, the cutter (12) will be pushed into the thinnest part of the chip that was created on the prior pass, which will cause it to break. Otherwise, the wave patterns would be always parallel, producing a chip that was wavy, but still continuous. The apparatuses and methods used to assure a phase shift are complex and expensive, but necessary. Referring next to FIGS. 3 and 4, a preferred embodiment of the invention is shown. The same workpiece, indicated at 10', is machined, with the same rates of rotation, radial advance, and axial feed. A tool holder, indicated generally at (16), is basically a hollow steel cylinder, capped at one end by a steel plate (18) that is bolted on its lower side at (20) and free on the opposite side. Plate (18) is thus capable of bending to an extent about the single bolt (20). The free side of plate (18) also supports a cutter (22), which could be any commercially available cutter, generally referred to as an insert. Cutter (22) is oriented so that its cutting edge is clear of and leads the tool holder (16). The interior of tool holder (16) comprises a stepped bore that contains an impulse actuator (24), which closely fills much of the bore. Impulse actuator (24) as disclosed is a cylindrical block of a piezoelectric material, such as PbZrO 3 -PbTiO 3 . Piezoelectrics are capable of very rapid expansions and contractions in length in response to a rapid applied voltage change, which results from shape deformations induced in their crystalline structure. Specifically, it would expand in response to a raised voltage, and contract in response to a lowered voltage, to a degree of perhaps 0.1 or 0.2 percent. While the percentage change is not great, the response time is rapid, on the order of a millisecond. Ahead of actuator (24) is a master piston (26), which engages the end of actuator (24), and a radially offset, smaller diameter, slave piston (28), which engages plate (18) near cutter (22). Separating pistons (26) and (28) is a chamber (30) filled with hydraulic fluid. An adjusting set screw (32) threaded through plate (18) engages the end of slave piston (28). Completing the apparatus is a controller (34), a commercially available impulse voltage generator which is generally called a fast switching controller. Controller (34), as its name indicates, is normally used to provide ultra fast on-off switching of electrical components, and is capable of dropping and reapplying a required voltage and current, in less than a millisecond. Still referring next to FIGS. 3 and 4, the operation of the invention is described. When tool holder (16) is moved, cutter (22) engages the surface of workpiece 10' and produces a chip as in any conventional turning operation. The chip breaking motion superimposed on cutter (22) is different, however. A constant voltage is normally applied to actuator (24) by controller (34). The normal voltage keeps actuator (24) in an expanded condition. The expansion of actuator (24) pushes master piston (26) forward, a motion that is amplified by chamber (30) into a greater axial advance of slave piston (28). Slave piston (28), in turn, pushes plate (18) out and away slightly, advancing cutter (22), and putting plate (18) under residual tension. Set screw (32) is adjusted so as to assure that plate (18) responds quickly to slave piston (28), with no lost motion. When the voltage is removed, actuator (24) contracts just as quickly, and cutter (22) withdraws as plate (18) springs back. When the voltage is dropped and reapplied during the cutting process, cutter (22) is withdrawn from the cut slightly, and then pushed back quickly into it. If the increment of superimposed axial motion is sufficient, the chip will be severed with a quick, chopping action. The increment of axial movement of cutter (22) need not be very great, perhaps only 80% of the axial feed per revolution, which could be in the order of 0.01 inches. Referring next to FIG. 5, the result of the operation described is shown graphically. The axial feed per revolution is indicated at D. As noted above, the speed at which controller (34) switches is very rapid, indicated at Δt, and the wave form that results is correspondingly sharp and choppy, not sinusoidal. This is because cutter (22) is normally still (relative to tool holder (16)), and is withdrawn and returned in impulsive, rapid fashion, rather than continually moving. The frequency with which controller (34) would be switched off and on would be determined only by how frequently it was desired to break the chip, which would, in turn, simply depend on how short a chip was desired. The surface speed at which cutter (22) moves relative to workpiece (10') is calculable for any given rotation rate and circumference of workpiece (10'), and, divided by the desired chip length, yields the necessary pulsing frequency. There is no need to synchronize the impulse frequency with the rate of rotation of workpiece (10'), because the chopping action works independently from one rotation to the next. There is no need to avoid in-phase sinusoidal patterns, as with the known methods of chip breaking. Variations of the embodiment disclosed could be made. The same principal of impulsive, short burst actuation of a tool holder, resulting in equally fast, incremental motion of a tool, could be applied to other machining processes in which a chip is continuously formed. For example, in boring or drilling operations, chips are continuously formed by the drill cutting edges as they turn against a cone shaped cutting interface at the bottom of the hole. It is far easier to flush and expel chips from the hole if they are broken up into smaller pieces, and drill wear and penetration rates depend on efficient chip flushing. In boring, the tool rotates, rather than the workpiece, but if the same impulsive chopping motion could be created in the drill, its edges could accomplish the same chopping action. Such an apparatus would require some kind of support mechanism, such as a slip ring, which would allow the axial motion of a non rotating impulse actuator to be effectively applied to the rotating drill, in the same way that the pushing force of a stationary clutch release lever is applied to a spinning clutch through the medium of a clutch release bearing. As well as boring and drilling, the same basic concept could be applied to any operation where a continuous chip is formed by a cutter, such as grooving, broaching, or cut off operations. The common thread is the impulsive actuation of the cutting tool in a direction generally perpendicularly to the direction the chip that the tool is continuously forming, thereby creating the chopping, chip cutting action. In the turning operation illustrated, or other chip forming process, impulse actuators made of different materials could be used, so long as they had the same characteristic response of rapid, impulsive expansion and contraction. For example, magnetostrictive materials exist which expand and retract quickly in response to an applied magnetic field. A different means could be used to amplify the action of the actuator, such as a lever. Or, in other cases, especially with small rates of axial feed, no amplification might be necessary, and the actuator could act directly on the cutter. Through a multiplexing arrangement, the signal from one controller could be fed to several tooling stations. Therefore, it will be understood that it is not intended to limit the invention to just the embodiment disclosed.

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to superconductive circuits, and particularly to a soliton sampler for super-conductive circuits. 2. Description of the Prior Art There are sampling circuits availble for super-conductive circuits. These sampling circuits, which sample the output waveform of the device under test, normally require sampling pulses of very narrow width and very fast rise time. Such pulses are subject to jitter and crosstalk. There is a tradeoff relationship between jitter and crosstalk; very fast rise times minimize jitter, but the resulting increased flux increases induced crosstalk in neighboring conductors. SUMMARY OF THE INVENTION The invention is an all-soliton sampler for measuring the output waveform of very high speed circuits. A soliton is directed into two parallel branches, one including the device under test and the other including a programmble delay line implemented in soliton devices. The outputs of these two branches are used as controls to a soliton comparator which, in turn, controls a Josephson detector gate. This circuit permits a relatively slow rise time external trigger pulse to initiate an extremely narrow sampling pulse. An object of the invention is to reduce the width of the sampling pulse to the picosecond range, in order to obtain better sampling resolution. In comparison, it is very difficult to obtain a resolution of 1 ps with the conventional Josephson sampler. In the soliton sampler according to this invention, extremely narrow test-gate trigger signals and sampling pulses (of width ≲1 ps) are generated simultaneously by an external trigger with a relatively long rise time. The addition of an on-chip programmable delay circuit allows high-resolution sampling to be done without appreciable jitter. Problems with crosstalk are alleviated by allowing a long rise time on the external trigger. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of the invention. FIG. 2 is a schematic diagram of the programmed delay unit in the preferred embodiment. FIG. 3 is a waveform of operation. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a schematic diagram of the invention. Input terminal 1 receives an input signal from a relatively long rise time external source, for triggering a soliton. The soliton, which will be more specifically defined and described in the paragraph following this paragraph, may be thought of as an energy wave generated by long Josephson junction 2 and propagating through the mechanism 3-16 to provide a control signal to output device 17. The generated soliton follows the length of long Josephson junction 2, and divides equally at Nodes 1 and 2 via respective resistances 3, 4 into respective forked soliton device pathways 5, 6. Solitons progagate in each of the two branches. One soliton from fork 5 at Node 3 propagates through test connection means Node 3 to device-under-test 7 onto line 15. at Node 4. The other soliton from fork 6 propagates through programmable delay 8 onto forked soliton device 9, 10, 11, 12 and 14 to Nodes 5 and 6; a signal (from device-under-test 7) at Node 4 on line 15 overcomes bias from line 16, enabling soliton fork 14 at Node 6 so as to permit the soliton to activate output device 17. On the other hand, if the signal on line 15 is smaller than the bias on line 16, then the soliton is dissipated at Node 5 in resistance 13. The partial differential equation known as the sine-Gordon equation has among its solutions those which are called solitary waves. These waves propagate without fundamental changes in shape because of the nonlinear properties of the media which the equation describes. Solitons are those solutions which represent particle-like wave packets which under certain conditions may pass through each other without suffering a loss of identity. The equation describing wave propagation in a long Josephson junction is a perturbed sine-Gordon equation. The soliton solutions represent the motion of magnetic vortices or fluxons which are accelerated by the Josephson tunnel current. The motion of these (and any other types of) sine-Gordon solitons obeys the laws of special relativity, in that as the fluxons are accelerated, they narrow in spacial width; the voltage pulse associated with the excitation grows accordingly. A Josephson soliton which is traveling at non-relativistic velocities has a width of ˜2πλ J , where λ J is the so-called Josephson penetration depth. The properties of Josephson junctions with current densities of a few kA/cm 2 and junction transmission line velocities of ˜0.02 times the speed of light result in soliton voltage pulses of ˜ picosecond duration. The narrowing of pulses due to relativistic acceleration during transmission through the junction yields the possibility of entry into the subpicosecond domain. Long Josephson junction 2 is of length greater than two Josephson penetration depths; it thus generates a soliton which is dissipated in resistances 3 and 4 at the same time, launching a soliton in each of branches 5 and 6 of a forked-shape junction. A DC bias current is fed to each of these branches to insure only forward soliton propagation. The soliton in branch 6 is delayed in soliton delay circuit 8; it is then fed to soliton comparator 9-14, which includes another forked-shaped soliton device 12,14. The soliton in 5 is used to trigger the device-under-test 7. The output from device-under-test 7 is fed as a control current on conductor 15 to the comparator. The other control signal is a DC bias signal on conductor 16. The algebraic sum of signals on conductors 15 and 16 determines whether the sampling soliton is converted to a voltage pulse at the output of the detector gate 17 or whether the sampling soliton is dissipated in resistance 13. Feedback may be employed to maintain a predetermined fraction of detected pulses in output device 17. The on-chip delay circuit 8 may take many forms. One method is shown in FIG. 2. The input soliton is fed to input 6 of an array of forked-shaped junctions. One may, for instance, desire the capability for 256 time increments Δ, yielding the necessity of an eight-bit array with junctions 8.0-8.7 of time delays that are approximately integral multiples of Δ. The minimum delay is 8δ, where δ>>Δ, while the maximum delay is 255Δ+8δ. A binary counter 8.10 controls inputs C1, C2, . . . C8, according to its setting which determine the appropriate path for the soliton. Backward propagation of the signal is prevented by resistors similar to 3-4 and bias lines similar to 16 shown in FIG. 1. The soliton is ultimately fed to soliton comparator 9, which is the input path to a forked soliton device 12,14. A forked soliton input 9. A simulation of the output pulses from a single stage of such a delay line is described in FIG. 3. All soliton-bearing junctions must be supplied with a DC bias. This may be accomplished either with directly-injected currents or by magnetically-induced circulating currents. The ultimate resolution of this device is limited by the width of the detected voltage pulses, which as shown in FIG. 3, may be of ˜1 ps duration. The properties of solitons (to propagate without dispersion, in contrast to signals in conventional superconducting devices) ensure that signals are not degraded in the pulse generator, delay junctions or comparator junctions. Problems associated with crosstalk are avoided by being able to use a slowly-rinsing trigger pulse. Jitter is minimized by the on-chip delay scheme. It is emphasized that although Josephson junctions are used to generate and propagate the solitons, the solitary-wave phenomena used in the sampler are not confined to superconductivity per se, and are not contained in the body of phenomena originally predicted by Josephson.

4y

FIELD OF THE DISCLOSURE The present application relates generally to the field of well completion assemblies for use in a wellbore and, more specifically, to a method and apparatus for opening a pressure actuated valve controlling fluid flow between an annulus and an interior of a production zone within a tubing string in a wellbore. DESCRIPTION OF THE RELATED ART Mechanical sleeve valves, such as BJ Services Company's family of Multi-Service Valves, are used in subterranean wells to provide zone isolation and bore completion control for completion operations such as gravel packing, spot acidizing and fracturing, killing a well, or directing flow from the casing to the tubing in alternate or selective completion operations. In such operations, the sleeve valve provides fluid communication between the tubing string, such as the inner diameter of the valve, and the outside of the valve, such as a well annulus. Typically, mechanical sleeve valves are opened or closed, such as by a shifting tool that is placed within the valve body and manipulated by standard wireline and/or coiled tubing methods. The sleeve, which seals the fluid communication path, can be physically moved from the closed to opened position, and vice versa, by these methods. There also exist hydraulically actuated sleeve valves, such as Well Dynamics' CC Interval Control Valve, in which opening and closing of the valve is achieved remotely with the use of one or more hydraulic control lines. In these types of hydraulic sleeve valves, a pressure differential across a defined piston area causes the sleeve to move in the desired direction. Other sleeve valves operate by applying or increasing pressure in the downhole bore to unlock the sleeve valve and then bleeding the applied pressure to allow the valve to open using mechanical means, such as a compressed spring, for example. There are times when an operator would like to pressurize and bleed the pressure in the downhole bore without opening the sleeve valve. Currently, one of the methods to accomplish this is to shear pin the valve in the closed position requiring relatively high pressure to shear the pin and open the valve. Any operations requiring the downhole bore to be pressurized prior to opening the valve is limited to a somewhat lower pressure. Locking the sleeve valve closed with a shear pin is both inconvenient and hazardous. A possibility of over pressurizing the downhole bore and opening the sleeve valve prematurely always exists. Alternatively, using a shear pin that requires a sufficiently high pressure to avoid premature opening poses a hazard when the downhole bore is pressurized at the high pressure required to shear the pin and unlock the valve. What is needed is an improved hydraulic sleeve valve that allows the downhole bore to be pressurized one or more times without premature opening of the sleeve valve and without the hazards presented by the requirement to set the shear pressure a very high level. SUMMARY OF THE DISCLOSURE The present disclosure provides a system which allows an operator to pressurize and bleed a downhole bore without premature opening of a sleeve valve and not requiring the use of a mechanical tool to manually shift the valve. In one embodiment, a double ratchet assembly adapted for moving a valve release sleeve in a first direction and preventing movement of the release sleeve in a second direction opposite the first direction includes a release sleeve having an outer diameter and an outer surface; the release sleeve enclosed in and surrounded by an outer housing, the inner diameter of the outer housing being greater than the outer diameter of the release sleeve and forming an annular void between the outer housing and the release sleeve. An upper housing connector is connected to a proximal end of the outer housing adjacent to the release sleeve; a lower housing connector is connected to a distal end of the outer housing adjacent to the release sleeve. A release piston is disposed within the annular void between the outer housing and the release sleeve, the release piston being moveable in the annular void between the upper connector and the lower connector. A first ratchet mechanism having an inner and outer surface, the inner surface of the first ratchet mechanism adapted to selectively engage the release sleeve and a first ratchet carrier having an inner surface adapted to selectively engage the outer surface of the first ratchet mechanism, the first ratchet carrier moving the release sleeve in a first direction in response to the release piston moving in the first direction. A second ratchet mechanism having an inner and outer surface, the inner surface of the second ratchet mechanism adapted to selectively engage the release sleeve and a second ratchet carrier having an inner surface adapted to selectively engage the outer surface of the second ratchet mechanism. The second ratchet mechanism allowing motion of the release sleeve in the first direction, but preventing movement of the release sleeve in a second direction in response to the release piston moving in the second direction. A spring disposed within the annular void and between the upper connector and the release piston biasing the release piston in the second direction. In another embodiment, a rotating ratchet assembly adapted for moving a release sleeve in a first direction includes a release sleeve having an outer diameter and an outer and inner surface, and a housing assembly having a proximal end and a distal end, and an inner diameter greater than the outer diameter of the release sleeve, the housing assembly surrounding the release sleeve. A release piston having a proximal end and a distal end is disposed within the housing assembly; the proximal end of the release piston is disposed adjacent to and spaced from a proximal end of the release sleeve. A ratchet mechanism is disposed between the proximal end of the release piston and the proximal end of the release sleeve, the ratchet mechanism adapted to rotate in a direction transverse to a motion of the release piston in response to the motion of the release piston. The ratchet mechanism is adapted to move the release sleeve in a first direction when the ratchet mechanism has rotated through a first predetermined radial angle. A spring is disposed within the annular void between the housing connector and the release piston biases the release piston in a second direction. In one embodiment of the present disclosure, a pressure actuated valve (“PAV”) is adapted to be positioned in a subterranean well bore having at least an upper zone and an upper zone pressure. A PAV as described herein includes a plurality of flow openings through the wall of a pipe or tubing, and a first piston (also referred to herein as a “release piston”) and a second piston (also referred to herein as a “valve piston”), wherein the first and second pistons are independently actuatable relative to one another. The PAV also includes a closing sleeve that is operatively coupled to the second piston. The closing sleeve is adapted to be positioned so as to block or not block the plurality of flow openings. In an initial position of the second piston, the closing sleeve covers or blocks the plurality of flow openings. The first piston is movable when a pressure within the valve is greater than an upper zone pressure in the well, while the second piston is movable when the pressure within the valve is approximately equal to or less than the upper zone pressure within the well. The PAV also comprises a first biasing mechanism or spring positioned proximate the first piston (release piston), the first spring being adapted to apply a biasing force to the first piston so as to urge the first piston to move towards its initial position. The first piston is coupled to the second piston by a release sleeve. The valve also includes a plurality of actuatable members, such as spring actuated dogs, that engage the second piston when the first and second pistons are in their initial positions and thereby secure the second piston in its initial position. The second piston is secured in its initial position until unlocked and released by a predetermined number of cycles of reciprocal movement of the first piston. The PAV also comprises a second biasing mechanism or spring positioned proximate the second piston (valve piston), the spring being adapted to apply a biasing force to the second piston so as to urge the second piston to move toward a final position so as to uncover the plurality of flow openings. The PAV includes a ratchet mechanism coupling the release sleeve to the first piston, the ratchet mechanism being adapted to allow movement of the first piston between its initial position and the intermediate position and back to its initial position while allowing the release sleeve to release the second piston after a predetermined number of cycles of movement of the first piston between its initial position and the intermediate position and back to its initial position. Upon release of the second piston by the release sleeve, the second piston, and the closing sleeve, responsive to the urging of the second spring, will move to its final position uncovering the plurality of flow openings. An improved hydraulic sleeve valve for use in subterranean wells is disclosed. The valve comprises a body having a plurality of flow ports allowing communication from outside the body to inside the body. A movable sleeve may be sealed to the inside of the body such that in one position the sleeve prevents flow through the body flow ports and in another position flow therethrough is facilitated. The sleeve may be moved from the closed position to the opened position by a pressure differential which may be applied across one or more pistons associated with the sleeve. The improved sleeve valve comprises a first piston or a release piston that provides a ratcheting action to unlock the valve as a result of repeated pressure applications to the release piston. The sleeve valve is then opened by a spring-biased second piston or valve piston. BRIEF DESCRIPTION OF THE DRAWINGS The following figures, in which like numerals indicate like elements, form part of the present specification and are included to further demonstrate certain aspects of the present application. The present application may be better understood by reference to one or more of these figures in combination with the detailed written description of specific embodiments presented herein. FIGS. 1A , 1 B and 1 C illustrate a cross-sectional side view of a prior art pressure activated control valve in a locked-closed configuration; FIGS. 2A , 2 B and 2 C illustrate a cross-sectional side view of the prior art pressure activated control sleeve valve of FIGS. 1A , 1 B and 1 C in an unlocked-closed configuration; FIGS. 3A , 3 B and 3 C illustrate a cross-sectional side view of the prior art pressure activated control valve of FIGS. 1A , 1 B and 1 C in an open configuration; FIGS. 4A-4E illustrate a cross-sectional side view of one embodiment of a valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration; FIGS. 5A-5E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a first tubing pressure increase cycle of the embodiment shown in FIGS. 4A-4E ; FIGS. 6A-6E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a first tubing pressure bleed cycle of the embodiment shown in FIGS. 4A-4E ; FIGS. 7A-7E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a final tubing pressure increase cycle of the embodiment shown in FIGS. 4A-4E ; FIGS. 8A-8E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an open configuration after a final pressure bleed cycle of the embodiment shown in FIGS. 4A-4E ; FIG. 9 is a side cross-section view of a double-ended ratchet collet 228 used in one embodiment of a double ratchet mechanism shown in FIGS. 4A-8E ; FIG. 10 is a side cross-section view of a ratchet collet carrier 224 used in conjunction with the double-ended ratchet collet 228 of FIG. 9 ; FIG. 11 is an isometric view of a body lock ring 234 used in one embodiment of a double ratchet mechanism shown in FIGS. 4A-8E ; FIG. 12 is a cross-section view of one embodiment of the outer engaging teeth of the body lock ring 234 that engage the body lock ring carrier 232 and inner teeth that engage the release sleeve 216 shown in FIGS. 4A-8E ; FIG. 13A is a cross-section view of one embodiment of the outer engaging teeth of the double-ended ratchet collet 228 that engage the ratchet collet carrier 224 and inner teeth that engage the release sleeve 216 shown in FIGS. 4A-8E ; FIG. 13B is a cross-section view of another embodiment of the release sleeve 216 teeth that engage the inner teeth of the double-ended ratchet collet 228 ; FIGS. 14A-14E illustrate a cross-sectional side view of another embodiment of a valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration; FIGS. 15A-15E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration after a first tubing pressure applied cycle shown in the embodiment of FIGS. 14A-14E ; FIGS. 16A-16E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration after a first tubing pressure bleed cycle of the embodiment shown in FIGS. 14A-14E ; FIGS. 17A-17E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a final tubing pressure applied cycle shown in the embodiment of FIGS. 14A-14E ; FIGS. 18A-18E illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an open configuration after a final tubing pressure bleed cycle shown in the embodiment of FIGS. 14A-14E ; FIGS. 19A and 19B illustrate a top view of the rotating ratchet mechanism of the embodiment shown in FIGS. 14A-18E . These and other embodiments of the present application will be discussed more fully in the following detailed description. The features, functions, and advantages can be achieved independently in various embodiments of the present application, or may be combined in yet other embodiments. The figures and detailed descriptions of these specific embodiments are not intended to delimit all embodiments of the disclosure or to limit the breadth or scope of the described concepts or the appended claims in any manner. Rather, the figures and detailed written descriptions are provided to illustrate the disclosed concepts to a person of skill in the art. DETAILED DESCRIPTION One or more illustrative embodiments incorporating the disclosure described herein are presented below. Not all features of an actual implementation are necessarily described or shown for the sake of clarity. For example, the various seals, vents, joints and others design details common to oil well equipment are not specifically illustrated or described. It is understood that in the development of an actual embodiment incorporating the present disclosure, numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related, and other constraints, which vary by implementation and from time to time. While a developer's efforts might be complex and time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art having benefit of this disclosure. As used within this description, relative and positional terms, such as, but not limited to “up” and “down”, “upward” and “downward”, “upstream” and “downstream”, “upper” and “lower”, “upwardly” and “downwardly”, and other like terms are used in this description to more clearly describe some embodiments of the disclosure. In various ones of the figures, the drawings may be oriented horizontally; in such figures, the left side of the figure is “up” or “uphole” and the right side of the figure is “down” or “downhole.” However, when applied to apparatus and methods for use in wells that are deviated or horizontal, such terms may refer to a “left to right”, “right to left”, or other relationship as appropriate. Also, as used herein the terms “seal” and “isolation” are used with the recognition that some leakage may occur and that such leakage may be acceptable. An improved hydraulic sleeve valve for use in subterranean wells is disclosed. The valve comprises a body having a plurality of flow ports allowing communication from outside the body to inside the body. A movable sleeve may be sealed to the inside of the body such that in one position the sleeve prevents flow through the body flow ports and in another position flow therethrough is facilitated. The sleeve may be moved from the closed position to the opened position by a pressure differential which may be applied across one or more pistons associated with the sleeve. The improved sleeve valve comprises a release piston that provides a ratcheting action to unlock the valve as a result of repeated pressure applications to the release piston. The sleeve valve is then opened by a spring-biased valve piston. Referring now to FIGS. 1A-3C , a cross-sectional side view of a prior art pressure actuated control valve 100 (“PAC”). PAC 100 generally comprises an outer housing or tube 101 constructed of several sections. A top connector housing 102 is disposed at the upper end of the PAC 100 . The top connector housing 102 includes an internally threaded portion 104 and a set screw 105 at the top end thereof for receiving and coupling to an externally threaded stub 106 . At the lower end of the top connector housing 102 , the upper end of a release piston carrier 108 is received by an internally threaded portion 110 thereby coupling the release piston carrier 108 to the top connector housing 102 . Housing extension 112 is coupled to the lower end of the release piston carrier 108 and to the upper end of an upper body section 114 . Each end of the housing extension 112 is internally threaded to engage externally threaded portions 113 and 116 at the lower end of the release piston carrier 108 and the upper body section 114 , respectively. A housing lower body section 118 is coupled to the lower end of the upper body section 114 and to the upper end of a lower housing section 120 . The upper and lower ends 115 and 117 , respectively, of the housing lower body section 118 are threaded and are received by corresponding threaded sections of the upper body section 114 and the lower housing section 120 . An externally threaded upper end 121 of a housing connector 122 is received by and coupled to a corresponding internally threaded lower end of lower housing section 120 . The externally threaded lower end 123 of the housing connector 122 is received by an internally threaded upper end of and coupled to a lower cross-over section 124 . An inner housing or tube 130 is generally constructed within a lower portion of the outer housing of the PAC 100 and extends upwards from the bottom or lower end of the PAC 100 . An inner housing section 132 is disposed within and concentric with the PAC 100 outer housing 101 . An externally threaded portion of the upper end 134 of the inner housing section 132 is received by and coupled to a corresponding internally threaded portion 136 of the lower housing section 120 and is securely held in position with set screw 135 . The inner housing section 132 is spaced from the outer housing 101 . A number of fluid ports 133 are formed around the circumference of the inner housing section at the upper end of the inner housing 132 . An inner lower connector section 138 is spaced from and disposed within and concentric with the outer housing 101 below the inner housing section 132 . An externally threaded portion of the upper end 140 of the inner lower connector section 138 is received by and coupled to a corresponding internally threaded portion 142 of the inner housing section 132 and is securely held in position with set screw 141 . An annular space is formed between the inner housing 130 and the lower portion of the outer housing 101 which defines a fluid flow path 150 to communicate fluid between the inner housing 130 and the outer housing 101 to the fluid ports 133 . A closing sleeve 144 is slidably disposed within the inner housing 130 adjacent to the inner housing section 132 and extends upwards within the PAC 100 . A portion 146 of the closing sleeve 144 is formed to slide over the fluid ports 133 to completely restrict the flow of fluid through the ports 133 (as shown in FIGS. 1B and 2B ). The lower portion of the closing sleeve 144 has a number of fluid ports 148 formed through and around the circumference of the closing sleeve 144 . When the closing sleeve 144 is allowed to move in an upwardly direction within the PAC 100 until the closing sleeve fluid ports 148 are aligned with the fluid ports 133 , fluid is allowed to flow from the annular space 150 between the inner housing 130 and the outer housing 101 to the inner bore or tube 151 of the PAC 100 . An annular space 152 is formed between the closing sleeve 144 and the lower housing section 120 . A spring 154 is disposed in the lower portion of the annular space 152 and bears against a spring retainer ring 156 held in place by one or more retainer keys 158 inserted in through holes provided in the wall of the lower housing section 120 at the upper end of the inner housing 132 . The upper end of the spring 154 bears against seal retainer ring 160 . A valve piston 162 is disposed in the upper portion of annular space 152 and extends upwardly between the upper end of the closing sleeve 144 and lower and upper housing body sections 118 and 114 , respectively. The lower end of valve piston 162 is internally threaded for receiving the seal retainer ring 160 and coupling it thereto. A piston cap 166 is mounted at the upper end of the valve piston 162 by a threaded portion 167 . The valve piston 162 is secured to the closing sleeve 144 at its upper end by one or more shear screws 164 about the inner circumstance of the valve piston 162 . The closing sleeve 144 is selectively retained in position over the fluid ports 133 by one or more actuatable members, such as spring-biased dogs 168 , for example, mounted in an upper portion of upper body section 114 and extending into slot 170 formed about the outer circumference of the valve piston 162 . A release piston 172 is slidably disposed in annular space 171 formed between the release piston carrier 108 and seal bore connector 174 disposed within and concentric to the PAC 100 outer housing 101 . A release piston lower extension 176 extends downwardly into an annular space 178 formed between housing extension 112 and the upper end of upper body section 114 and piston cap 166 . Typically, the PAC 100 is run into a wellbore in a locked-closed configuration, as shown in FIGS. 1A-1C , wherein the uphole end is on the left of FIG. 1A and the downhole end is on the right end of FIG. 1C . In the locked-closed configuration, the portion 146 of the closing sleeve 144 covers the fluid ports 133 . In the locked-closed configuration, the spring 154 is compressed biasing the valve piston 162 in an upwardly direction. The release piston lower extension 176 covers the spring-biased dogs 168 maintaining them in slot 170 in the valve piston 162 and preventing the valve piston 162 , and thus the closing sleeve 144 , from moving upwards and aligning the sleeve fluid ports 148 with the fluid ports 133 . The release piston lower extension 176 is held in place by one or more shear pins 180 protruding from a portion 182 of the upper end of the upper body housing section 114 and extending through release piston lower extension 176 . The PAC 100 may be reconfigured to an unlocked-closed (sheared) configuration, as shown in FIGS. 2A-2C . The PAC 100 is unlocked by creating a pressure differential between the inner bore or tube 151 of PAC 100 and upper portion of annular space or void 171 . The inner bore 151 is pressurized by pressuring down the wellbore tubing (not shown) coupled to the upper end of the top connector housing 102 via stub 106 at internally threaded portion 104 . Increased pressure is thus asserted against the face 173 of the release piston 172 . Vents 175 and 177 vent the annular space 171 to the exterior of the outer housing 101 creating a pressure differential across the release piston 172 driving the release piston 172 upwards in the annular space 171 . The action of the release piston 172 moving upwards uncovers the release piston snap ring 184 allowing the snap ring 184 to contract slightly into an elongated annular groove 186 and prevent the release piston 172 from moving downwardly when the increased pressure in the inner bore 151 is bled off. As the release piston 172 moves upwardly, the release piston lower extension 176 shears the shear pins 180 and uncovers the spring-biased dogs 168 . When the dogs 168 are uncovered, a spring, such as a leaf spring, for example, forces the dogs 168 outwardly and out of the slot 170 and the closing sleeve 144 is free to slide upwardly. As long as increased pressure is maintained in the inner bore 151 , pressurized fluid bears against the face 179 of the piston cap 166 preventing the closing sleeve from sliding upwardly and opening the fluid ports 133 . FIGS. 3A-3C illustrate the PAC 100 in an open configuration, wherein the uphole end is on the left and the downhole end is on the right. The valve is opened by bleeding, i.e., reducing, the pressure in the inner bore 151 . When the inner bore pressure is bled off, the compressed spring 154 expands against the lower end of the valve piston 162 pushing the valve piston 162 , and thus the closing sleeve 144 , upwardly until the closing sleeve fluid ports 148 are aligned with the fluid ports 133 allowing fluid to flow from the annular space 150 between the inner housing 130 and the outer housing 101 to the inner bore or tube 151 of the PAC 100 . Referring now to FIGS. 4A-8E , a cross-sectional side view of one embodiment of a valve opening mechanism for a pressure actuated sleeve valve 200 (“PAV”) according to the present disclosure is shown. The construction and operation of the PAV 200 is similar to the construction and operation of the PAC 100 described above. The PAV 200 valve opening mechanism and operation allows the fluid pressure in the inner bore or tube to be increased and decreased (bled) for several cycles, for example five cycles, prior to opening the valve. In contrast, the opening mechanism and operation of PAC 100 opened the valve at the end of a single pressurize and bleed cycle. PAV 200 generally comprises an outer housing or tube 201 constructed of several housing and connecting sections. A top connector housing 202 is disposed at the upper end of the PAV 200 . The upper or uphole end of the PAV 200 is on the left and the lower or downhole end is on the right as shown in the various figures. The top connector housing 202 includes a coupling portion at its top end (not shown) for receiving and coupling to uphole tubing or other components such as portions of an isolation string (not shown). At the lower end of the top connector housing 202 , the upper end of upper body connector 204 is received by an internally threaded portion 203 thereby coupling the upper body connector 204 to the top connector housing 202 . Release piston housing 206 is coupled to the lower end of the upper body connector 204 and to the upper end of a lower body connector 208 . Housing extension 210 is coupled to the lower end of the lower body connector 208 and to the upper end of an upper body section 214 . Each end of the housing extension 210 is internally threaded to engage externally threaded portions 211 and 213 at the lower end of the lower body connector 208 and the housing upper body section 214 , respectively. The lower section of PAV 200 below housing upper body section 214 is similar to the lower section of PAC 100 below housing upper body section 114 . As described above with reference to FIGS. 1A-3C , a closing sleeve 144 covers fluid ports 133 and has a number of fluid ports 148 formed through and around the circumference of the closing sleeve 144 below the fluid ports 133 . To open the valve, the closing sleeve 144 is allowed to move in an upwardly direction within the valve body until the closing sleeve fluid ports 148 are aligned with the fluid ports 133 . The closing sleeve 144 is secured to the valve piston 162 at its upper end by one or more shear screws 164 about the inner circumstance of the valve piston 162 . A piston cap 166 is mounted at the upper end of the piston valve 162 by threaded portion 167 . The closing sleeve 144 is retained in position covering the fluid ports 133 by one or more actuatable members, such as spring-biased dogs 168 , for example, mounted in an upper portion of upper body section 214 and extending into slot 170 formed about the outer circumference of the valve piston 162 . A release sleeve 216 is slidably disposed within and concentric to outer housing 201 . A release sleeve extension 217 extends into annular space 218 formed between housing extension 210 , and piston cap 166 and an upper end portion 220 of upper body section 214 . The release sleeve extension 217 covers and extends a predetermined distance, several inches, for example, below the spring-biased dogs 168 preventing the dogs 168 from retracting from slot 170 . A release piston 222 is slidably disposed within the annular space formed between the release sleeve 216 , and lower body connector 208 and release piston housing 206 . A ratchet carrier 224 near the upper end of release piston 222 includes ratchet teeth 225 formed around at least a portion of the surface of the inner circumference of the ratchet carrier 224 . The ratchet carrier 224 may be formed integrally with the release piston 222 or may be a separate component fixed or fastened to the upper end of release piston 222 . A double-ended ratchet collet 228 is placed between the release piston 222 and the release sleeve 216 concentric to and surrounding the release sleeve 216 for at least a portion of the outer circumference. The double-ended ratchet collet 228 is attached to a collet holder 229 between the release piston 222 and the release piston retainer ring 226 by set screw 237 , for example. Ratchet teeth 227 formed on the outer surface double-ended ratchet collet 228 opposite the ratchet carrier 224 engage the ratchet teeth 225 formed in the inner surface of the ratchet carrier 224 . As shown in FIGS. 9 , 13 A and 13 B, teeth 901 formed on the inner surface of double-ended ratchet collet 228 engage teeth or shaped slots 1301 formed on the outer surface of release sleeve 216 . A first spring 230 (or simply “spring 230 ” below) is disposed in the annular space formed between the release sleeve 216 and release piston housing 206 . The upper end of spring 230 bears against the lower end face 231 of upper body connector 204 while the lower end of spring 230 bears against release piston retainer ring 226 biasing the release piston 222 in a downwardly direction. A body lock ring carrier 232 at the lower end of upper body connector 204 includes ratchet teeth 233 formed in the inner surface for at least a portion of the inner circumference of the body lock ring carrier 232 . A body lock ring 234 is placed between the release piston 222 and the release sleeve 216 concentric to and surrounding the release sleeve 216 for at least a portion of the outer circumference of the release sleeve 216 . Ratchet teeth 235 formed on the outer surface of body lock ring 234 opposite the body lock ring carrier 232 engage the ratchet teeth 233 formed in the inner placed between the release piston 222 and the release sleeve 216 concentric to and surrounding surface of the body lock ring carrier 232 . As shown in FIGS. 11 and 12 , teeth 1101 formed on the inner surface of body lock ring 234 engage teeth 1201 formed on the outer surface of release sleeve 216 . Typically, the PAV 200 is run into a wellbore in a locked-closed configuration, as shown in FIGS. 4A-4E . In the locked-closed configuration, the closing sleeve 144 covers the fluid ports 133 , and the second spring 154 (or simply “spring 154 ” below) is compressed biasing the valve piston 162 in an upwardly direction. The release sleeve extension 217 covers the spring-biased dogs 168 maintaining them in slot 170 in the valve piston 162 and preventing the valve piston 162 , and thus the closing sleeve 144 , from moving upwards. The release sleeve extension 217 is held in place by one or more shear pins 180 protruding from a portion 221 of the upper end 220 of the upper body housing section 214 and extending through the release sleeve extension 217 . The PAV 200 may be reconfigured to an unlocked-closed (sheared) configuration, as shown in FIGS. 5A-5E . The PAV 200 is unlocked by creating a pressure differential across the release piston 222 between the annular space or void 236 formed between the release sleeve 216 and lower body connector 208 , and the annular space or void 238 formed between the release sleeve 216 and the release piston housing 206 . The inner bore 251 of PAV 200 is pressurized by pressuring down the wellbore tubing (not shown) coupled to the upper end of the top connector housing 202 . Fluid from the inner bore 251 bleeds into annular space 236 through orifices (not shown) provided in the release sleeve 216 at the corner where the release sleeve 216 joins the release sleeve extension 217 asserting increased pressure against the face 240 of release piston 222 . Vents (not shown) vent the annular space 238 to the annular area formed between the outer housing 201 and the upper body connector 204 creating a pressure differential across the release piston 222 driving the release piston 222 upwards in the annular space 238 compressing spring 230 against the face 231 of upper body connector 204 . As the release piston 222 moves upwards, the ratchet carrier 224 and the double-ended ratchet collet 228 moves in an upwardly direction. As the release piston 222 moves upwardly, the double-ended ratchet collet 228 is forced against the release sleeve 216 such that the teeth 901 formed on the inner surface of double-ended ratchet collet 228 engage teeth 1301 formed on the outer surface of release sleeve 216 moving the release sleeve 216 upwards along with the release piston 222 . In addition, as the release sleeve 216 is pulled upwards by the movement of the release piston 222 , the body lock ring 234 teeth 1101 slide over the teeth 1201 formed on the outer surface of the release sleeve 216 . The release piston 222 moves upwardly a predetermined distance, stopping its upward movement when upper end of the release piston retainer ring 226 contacts and butts against the lower end face 231 of upper body connector 204 . As the release sleeve 216 moves upwards, the release sleeve extension 217 slides upwardly a portion of the distance that it extends in the annular space 218 past the spring-biased dogs 168 shearing the shear pin 180 . Since the release sleeve extension 217 has only moved a portion of the distance it extends past the spring-biased dogs 168 , the dogs 168 remain covered by the release sleeve extension 217 thus preventing any upward movement of the closing sleeve 144 . When the fluid pressure in the PAV 200 inner bore 251 is reduced, the fluid pressure against face 240 of the release piston 222 bleeds off reducing the pressure differential across the release piston 222 . The reduced pressure differential allows spring 230 drive the release piston 222 downwards its original unpressurized position against the upper face 242 of lower body connector 208 . The downward motion of the release piston 222 allows the teeth 901 of ratchet collet 232 to slide over the teeth 903 of release sleeve 216 while the release sleeve body lock ring 234 teeth 1101 engage the teeth 1201 of release sleeve 216 preventing any downward movement of the release sleeve 216 as shown in FIGS. 6A-6E . For each additional pressurize and bleed cycle, the release sleeve 216 , and hence the release sleeve extension 217 will move upwards an additional predetermined distance. The distance the release sleeve 222 moves each pressurize/bleed cycle is determined by the distance 244 separating the upper end 246 of the release piston retainer ring 226 and the lower end face 231 of upper body connector 204 . The distance 244 is determined by the width of the spring-biased dogs 168 . In one embodiment, the release piston 222 moves upward about three-quarters of one inch for each pressurize/bleed cycle. The next to the last pressure/bleed cycle must leave the spring-biased dogs 168 completely covered and the last pressure/bleed cycle must completely uncover the spring-biased dogs 168 . In one embodiment, five pressurize/bleed cycles are required to uncover the spring-biased dogs 168 . To ensure that the release sleeve 216 moves substantially the same distance for each pressure/bleed cycle, the double-ended ratchet collet 228 teeth 901 are widely spaced so that the double-ended ratchet collet 228 catches one and only one additional tooth 1301 on the release sleeve 216 outer surface for each pressure/bleed cycle. FIGS. 7A-7E illustrate the PAV 200 configuration after the last pressurize cycle. The release sleeve 216 has now been moved upwards a sufficient distance to withdraw the release sleeve extension 217 from the annular space 218 to uncover the spring-biased dogs 168 . Once uncovered, the spring-biased dogs 168 are retracted from slot 170 , such as by the action of a leaf spring, for example, in the valve piston 162 . Fluid pressure on the face 179 of piston cap 166 overrides the compressed spring 154 preventing the closing sleeve 144 from sliding upwardly and opening the fluid ports 133 . The PAV 200 is opened by bleeding, i.e., reducing, the pressure in the inner bore 251 as shown in FIGS. 8A-8E . When the inner bore pressure is bled off, the compressed spring 154 expands against the lower end of the valve piston 162 pushing the valve piston 162 , and thus the closing sleeve 144 , upwardly until the closing sleeve fluid ports 148 are aligned with the fluid ports 133 opening the valve. Referring now to FIG. 9 , an isometric view, wherein arrow 911 indicates the upwards or uphole direction and arrow 913 indicates the downwards or downhole direction, of a double-ended ratchet collet 228 of one embodiment of the present disclosure is shown. The double-ended ratchet collet 228 includes longitudinal collet segments 903 separated by longitudinal slots 905 located around the circumference of the collet. The number and width of the longitudinal collet segments 903 may be varied depending on the application using the double ratchet mechanism. The interior surface of each collet segment 903 includes teeth 901 that are adapted to selectively engage the teeth 1301 formed on the outer surface of release sleeve 216 . The teeth 1301 form a thread, such as a buttress thread, for example, around the outside diameter of release sleeve 216 . Teeth 901 are relatively widely spaced to ensure that only one additional tooth 1301 is picked up for each additional pressurize/bleed cycle. The exterior surface of each collet segment 903 includes teeth 227 to engage with the teeth 225 formed in the inner surface of the ratchet carrier 224 . Referring now to FIG. 10 , one embodiment in accordance with the present disclosure of a ratchet collet carrier 224 is shown. The ratchet collet carrier 224 includes teeth 225 on the interior or inner surface, the teeth 225 being adapted to engage with the teeth 227 located on the collet fingers 903 . Openings 1001 around the perimeter of the ratchet collet carrier 224 may be used in one embodiment to secure the ratchet collet carrier 224 to the upper end of the release piston 222 by locking pins or set screws (not shown), for example. In some embodiments, a locking pin (not shown), for example, may be inserted through slot 1002 formed around the perimeter of the ratchet collet carrier 224 into a receiving slot (not shown) formed in the outside surface of ratchet collet 228 to prevent any relative rotation between ratchet collet carrier 224 and ratchet collet 228 . Referring now to FIG. 11 , an isometric view of a body lock ring 234 of one embodiment of the present disclosure is shown. The interior surface of the body lock ring 234 includes teeth 1101 that are adapted to selectively engage the teeth 2101 formed in the outer surface of release sleeve 216 . The body lock ring 234 includes a gap 1103 the formed in the body. The gap 1103 allows the body lock ring 234 to expand as it ratchets over the teeth 1201 on the release sleeve 216 (as shown in greater detail in FIG. 12 ). The gap 1103 aids in the selective engagement of teeth 1101 with teeth 1201 of the release sleeve 216 . The exterior or outer surface of the body lock ring 234 includes teeth 235 adapted to engage with the teeth 233 formed on the inner surface of body lock ring carrier 232 . The body lock ring 234 may include openings 1105 around the perimeter to aid in connecting the body lock ring 234 to the body lock ring holder 241 using locking pins or set screws (not shown), for example. Body lock rings are typically fabricated with the inner diameter small enough such that the inner threads clamp onto a mandrel such as the threaded portion of the release sleeve 216 , for example. Referring now to FIG. 12 , a cross-sectional view of the teeth of the body lock ring 234 according to one embodiment of the present disclosure is shown. The exterior surface of the body lock ring 234 includes teeth 235 that are adapted to engage the teeth 233 of the body lock ring carrier 232 . The body lock ring carrier 232 may be constructed similarly to ratchet collet carrier 224 as shown in FIG. 10 . The interior surface of the body lock ring 234 includes teeth 1101 that are adapted to engage the teeth 1201 on the outer surface of the release sleeve 216 . When pressure is applied moving the release piston 222 upwards carrying the release sleeve 216 with it, an angle substantially less than 90 degrees for the upwards face 1203 of the teeth 1201 allows the release sleeve 216 to move in an upwards direction, as shown by arrow 1207 sliding past the body lock ring 234 . As the release sleeve 216 moves upward, as shown by arrow 1217 , the body lock ring 234 is forced outwardly towards the body lock ring carrier 232 , the substantially 90 degree face 1209 of the teeth 235 on the outer surface of the body lock ring 234 engaging an opposing substantially 90 degree face 1211 of the teeth 233 on the interior surface of the body lock ring carrier 232 . When pressure on the release piston 222 is bled, i.e., reduced, the spring 230 forces the release piston 222 in a downwards direction. Any corresponding downwards motion of the release sleeve 216 , as shown by the arrow 1215 , is prevented by a substantially 90 degree face 1205 of the release sleeve teeth 1201 engaging with an opposing substantially 90 degree face 1213 of the teeth 1101 formed on the interior surface of the body lock ring 234 . Thus the body lock ring 234 acts to allow an upwards motion of the release sleeve 216 but prevents any downwards motion to return the release sleeve 216 to its original position. Conventional body lock rings, and corresponding body lock ring carriers, have a 90 degree face on both the inner and outer face. However, the 90 degree angles may actually only be about 85 degrees to allow the body lock ring, and corresponding body lock ring carrier, to be manufactured more easily. The body lock ring 234 in conjunction with the body lock ring carrier 223 of the present disclosure will allow the release sleeve to ratchet in one direction 1217 and will prevent movement of the release sleeve 216 when it is pushed in the other direction 1215 . Referring now to FIG. 13A , a cross-section view of one embodiment of the outer engaging teeth 227 of the double-ended ratchet collet 228 that engage the teeth 225 of the ratchet collet carrier 224 and inner teeth 901 that engage the shaped slots 1301 formed in the surface of the release sleeve 216 is shown. When pressure is applied moving the release piston 222 upwards carrying the release sleeve 216 with it, as shown by arrow 1319 , an angle substantially less than 90 degrees for the downwards face 1305 of the ratchet collet carrier 224 teeth 225 engages the downwards face 1303 of the double-ended ratchet collet 228 teeth 227 forcing the collet fingers 903 inwardly against the outer surface of the release sleeve 216 . The substantially 90 degree upwards face 1307 of teeth 901 formed on the inner surface of ratchet collect 228 engage the substantially 90 degree face 1309 of shaped slots 1301 formed on the outer surface of release sleeve 216 pulling the release sleeve 216 upwards, as shown by arrow 1319 , as the release piston 222 is forced upwards. When pressure on the release piston 222 is bled, i.e., reduced, the spring 230 forces the release piston 222 in a downwards direction as shown by arrow 1321 . The substantially 90 degree upwards face 1311 of the ratchet collet carrier 224 teeth 225 engage the substantially 90 degree face 1313 of the ratchet collect 228 outer teeth 227 pulling the double-ended ratchet collet 228 in a downwards direction. Since the release sleeve 216 is prevented from moving in a downwards direction by the locking action of the body lock ring 234 engaging the release sleeve 216 teeth 1201 , an angle substantially less than 90 degrees for the both downwards face 1315 of the ratchet collet carrier 224 inner teeth 901 and the downwards face 1317 of the shaped slot 1301 formed in the surface of the release sleeve allows the ratchet collet fingers 903 to expand outwardly pulling the double-ended ratchet collet 228 inner teeth 901 away from the release sleeve surface and out of the shaped slots 1301 . Referring now to FIG. 13B , as will be appreciated by those of skill in the art, in another embodiment of the present disclosure the shaped slots 1301 formed in the surface of the release sleeve 216 may be teeth 1327 protruding from the outer surface of the release sleeve 216 adapted to engage the inner teeth 901 of the double-ended ratchet collet 228 . When pressure is applied moving the release piston 222 upwards carrying the release sleeve 216 with it, as shown by arrow 1319 , the substantially 90 degree upwards face 1307 of teeth 901 formed on the inner surface of ratchet collect 228 engage the substantially 90 degree downwards face 1323 of teeth 1327 formed on the outer surface of release sleeve 216 pulling the release sleeve 216 upwards, as shown by arrow 1319 . When pressure on the release piston 222 is bled, i.e., reduced, the spring 230 forces the release piston 222 in a downwards direction as shown by arrow 1321 . Since the release sleeve 216 is prevented from moving downwards by the locking action of the body lock ring 234 engaging the release sleeve 216 teeth 1201 , as the release piston 222 pulls the double-ended ratchet collet 228 downwards, an angle substantially less than 90 degrees for the both the downwards face 1315 of the ratchet collet carrier 224 inner teeth 901 and the upwards face 1325 of the teeth 1327 formed in the surface of the release sleeve 216 allows the ratchet collet fingers 903 to expand outwardly pulling the double-ended ratchet collet 228 inner teeth 901 away from the release sleeve surface allowing the ratchet collet inner teeth 901 to slide over the release sleeve teeth 1327 . Referring now to FIGS. 14A-18E , a cross-sectional side view of another embodiment of a valve opening mechanism for a pressure actuated sleeve valve 300 (“PAV”) according to the present disclosure is shown. The construction and operation of the PAV 300 is similar to the construction and operation of the PAC 100 described above. Similar to PAV 200 , described above, the PAV 300 valve opening mechanism and operation allows the fluid pressure in the inner bore or tube to be increased and decreased (bled) for several cycles, for example five cycles, prior to opening the valve. PAV 300 generally comprises an outer housing or tube 301 constructed of several housing and connecting sections. A top connector housing 302 is disposed at the upper end of the PAV 300 . The upper or uphole end of the PAV 300 is on the left and the lower or downhole end is on the right as shown in the various figures. The top connector housing 302 includes a coupling portion at its top end for receiving and coupling to uphole tubing (not shown) or other components such as portions of an isolation string (not shown). At the lower end of the top connector housing 302 , the upper end of a release piston carrier 308 is received by an internally threaded portion 306 thereby coupling the release piston carrier 308 to the top connector housing 302 . Housing extension 312 is coupled to the lower end of the release piston carrier 308 and to the upper end of an upper body section 314 . Each end of the housing extension 312 is internally threaded to engage externally threaded portions 311 and 313 at the lower end of the release piston carrier 308 and the housing upper body section 314 , respectively. The lower section of PAV 300 (not shown) below housing upper body section 314 is similar to the lower section of PAC 100 below housing upper body section 114 . As described above, a closing sleeve 144 covers fluid ports 133 and has a number of fluid ports 148 formed through and around the circumference of the closing sleeve 144 below the fluid ports 133 . To open the valve, the closing sleeve 144 is allowed to move in an upwardly direction within the valve body until the closing sleeve fluid ports 148 are aligned with the fluid ports 133 . The closing sleeve 144 is secured to the valve piston 162 at its upper end by one or more set screws 164 about the inner circumstance of the valve piston 162 . A piston cap 166 is mounted at the upper end of the piston valve 162 by threaded portion 167 . The closing sleeve 144 is retained in position covering the fluid ports 133 by one or more actuatable members, such as spring-biased dogs 168 , for example, mounted in an upper portion of upper body section 314 and extending into slot 170 formed about the outer circumference of the valve piston 162 . A release piston 317 is slidably disposed within annular space 320 formed between the release piston carrier 308 and inner adapter 324 , respectively, and inner sleeve 322 Inner adapter 324 is disposed within and concentric to top connector 302 , and is coupled to top connector 302 by set screws 326 or other suitable coupler. The lower end of inner adapter 324 is coupled to the upper end of release piston carrier 308 at threaded portion 329 . Inner sleeve 322 is coupled to the inner adapter 324 at threaded portion 328 . A spring 321 disposed in the annular space 323 formed between the release piston 317 and housing extension 312 bears against the upper face 325 of release piston 317 and the lower face 319 of release piston carrier 308 . A release sleeve 316 extends into annular space 318 formed between housing extension 312 and piston cap 166 . The lower end 330 of release sleeve 316 covers the spring-biased dogs 168 preventing the dogs 168 from retracting from slot 170 , preventing the closing sleeve from moving upwards in the valve body. The release sleeve 316 is held in place by shear pin 180 extending through release sleeve 316 into piston cap 166 . The upper end 332 of release sleeve 316 extends into annular space 334 formed between housing extension 312 and release sleeve extension 336 extending from the lower face 338 of release piston 317 . A rotating ratchet mechanism 340 is disposed between the release sleeve upper end 332 and the release piston extension 336 and is adapted to rotate in a radial direction about the release piston extension 336 . A mounting bracket 342 slidably mounts rotating ratchet mechanism 340 to release piston extension 336 allowing the release piston extension 336 to move upwardly or downwardly as the release piston 317 moves upwardly or downwardly in annular space 320 while also allowing the rotating ratchet mechanism 340 to rotate about release piston extension 336 between release piston 336 and release sleeve upper end 332 . Referring now also to FIGS. 19A and 19B , a top view of the rotating ratchet mechanism 340 is shown. Two annular toothed rings 344 and 346 are fixed in opposing fashion in an annular case 350 . Annular case 350 is rotatably mounted to the release piston extension 336 by mounts 342 . Upper annular ring 344 is fixedly mounted to the uphole or upwards wall 343 of annular case 350 and comprises a number of teeth 345 formed in the annular ring at a predetermined pitch. Similarly, lower annular ring 346 is fixedly mounted to the downhole or downwards wall 341 of annular case 350 and comprises a number of teeth 347 formed in the annular ring at the same pitch and opposing the teeth 345 formed in upper annular ring 344 . Stops 348 are also formed at regular intervals, such as every five teeth, for example, between the teeth 347 of lower annular ring 346 . Lugs 352 formed on the inner surface of and at predetermined intervals about the inner circumference of release sleeve upper end 332 are adapted to mesh and engage teeth 345 and 347 formed on annular rings 344 and 346 , respectively. Lugs 352 may be an integral part of the release sleeve upper end 332 or may be separate components fixedly attached to the release sleeve upper end 332 . A pressure increase in the tubing inner bore 351 will force the release piston 317 in an upwards direction moving the rotating ratchet mechanism 340 in an upwards direction engaging the fixed lugs 352 . Since the release sleeve 316 is held in position by shear screw 180 , the lugs 352 remain stationary as the rotating ratchet mechanism 340 moves. As the rotating ratchet mechanism 340 moves in an upwards direction, as indicated by arrow 353 , the angled face 354 will engage the similarly angled face 360 of teeth 345 or of stop 348 causing the ratchet mechanism 340 to rotate a predetermined amount, such as about 18 degrees, for example, in the direction indicated by arrow 357 . Bleeding or reducing the pressure in tubing inner bore 351 allows pressure from the exterior of the valve and the compressed spring 321 to force the release piston 317 downwards moving the rotating ratchet mechanism 340 in a downwards direction. As the rotating ratchet mechanism 340 moves downwards, as indicated by arrow 355 , the angled face 358 of lugs 352 will engage the similarly angled face 356 of teeth 345 causing the ratchet mechanism 340 to further rotate approximately the same amount, such as about 18 degrees, for example, in the same direction as indicated by arrow 357 . Typically, the PAV 300 is run into a wellbore in a locked-closed configuration, as shown in FIGS. 14A-14E . In the locked-closed configuration, the closing sleeve 144 covers the fluid ports 133 , and the spring 154 is compressed biasing the valve piston 162 in an upwardly direction. The release sleeve extension 330 covers the spring-biased dogs 168 maintaining them in slot 170 in the valve piston 162 and preventing the valve piston 162 , and thus the closing sleeve 144 , from moving upwards. The release sleeve 316 is held in place by shear pin 180 extending through release sleeve extension 330 into piston cap 166 . The lugs 352 are positioned at the upper extent of the release piston downwards travel in the valve and are engaged with the teeth 345 against the upper annular ring 344 . The PAV 300 may be reconfigured to an unlocked-closed (sheared) configuration, as shown in FIGS. 17A-17E . The PAV 300 is unlocked by repeatedly pressurizing and then bleeding the pressure in the tubing inner bore 351 . Increasing the pressure in the inner bore 351 creates a pressure differential across the release piston 317 between the tubing inner bore 351 and the annular space or void 320 formed between the inner sleeve 322 and inner adapter 324 , and the annular space or void 323 formed between the release piston 317 and the housing extension 312 . The inner bore 351 of PAV 300 is pressurized by pressuring down the wellbore resulting in increased pressure against release piston 317 face 338 and release piston extension stop 337 . Vents (not shown) vent the annular space 323 to the annular space created between top connector housing 302 and inner adapter 324 (which in turn is vented to the exterior of the valve) creating a pressure differential across the release piston 317 driving the release piston 317 upwards in the annular spaces 320 and 323 and compressing spring 321 against the face 319 of release piston carrier 308 . In some embodiments, the annular space created between top connector housing 302 and inner adapter 324 may be vented to the zone above. Space 320 is vented to the tubing inner bore 351 through the annular space formed between the release piston 317 and the inner sleeve 322 . As the release piston 317 is pushed upwards, the rotating ratchet mechanism 340 moves upwards, as indicated by arrow 353 , and the angled face 354 of lugs 352 will engage the similarly angled face 356 of teeth 347 or stop 348 causing the ratchet mechanism 340 to rotate a predetermined amount, such as about 18 degrees, for example, in the direction indicated by arrow 357 . The release piston 317 will be forced upwards compressing spring 321 until the release piston upper end 362 abuts the face 364 of inner adapter 324 as shown in FIGS. 15A-15E . Bleeding or reducing the pressure in tubing inner bore 351 allows pressure from the valve exterior and the compressed spring 321 to force the release piston 317 downwards moving the rotating ratchet mechanism 340 downwards. As the rotating ratchet mechanism 340 moves downwards, as indicated by arrow 355 , the angled face 358 of lugs 352 will engage the similarly angled face 356 of teeth 345 causing the ratchet mechanism 340 to further rotate approximately the same amount, such as about 18 degrees, for example, in the same direction as indicated by arrow 357 . At the end of the first pressurize/bleed cycle, the release piston 317 will return to its original position, as shown in FIGS. 16A-16E , while the release sleeve 316 remains in its original locked position covering the spring-biased dogs 168 . The rotating ratchet mechanism 340 has been rotated the angular equivalent of one full tooth width now engaging the lugs 352 by the tooth immediately adjacent to the tooth originally engaging the lugs 352 . With each additional pressurize/bleed cycle, rotating ratchet mechanism 340 will rotate one additional tooth width. At the end of the next to the last pressurize/bleed cycle, the annular rings 344 , 346 will have rotated a sufficient amount to place the lug stops 348 opposite the lugs 352 , as shown in FIG. 19B . On the next, and last, pressurize cycle, as the release piston 317 is driven upwards, the face 365 of the lug stops 348 will impact the lugs 352 . As the release piston 317 continues to move upwards, the release sleeve 316 is forced upwards, withdrawing the release sleeve extension 330 shearing the shear pin 180 and uncovering the spring-biased dogs 168 allowing the dogs 168 to retract from slot 170 in the valve piston 162 . As long as the tubing inner bore 351 remains pressurized, fluid pressure on the face 179 of piston cap 166 overrides the compressed spring 154 preventing the closing sleeve 144 from sliding upwardly and opening the fluid ports 133 . In the above description, the rotating ratchet mechanism 340 is rotatably attached to the outer surface of the release piston extension 336 adjacent to the release sleeve upper end 332 while the lugs 352 are formed in and extend inwardly from the inner surface of the release sleeve upper end 332 to mesh with the rotating ratchet mechanism 340 teeth 344 , 346 . In this configuration, the rotating ratchet mechanism 340 moves in an upwards and downwards direction in response to the upwards and downwards movement of the release piston 317 , as shown by the arrows 353 and 355 , respectively, while the lugs remain stationary with respect to the release sleeve 316 . As will be appreciated by those of skill in the art, in another embodiment, rotating ratchet mechanism 340 may be rotatably attached to the release sleeve upper end 332 remaining stationary and not moving in an upwards or downwards direction in response to the movement of the release piston 317 . The lugs 352 are formed in the outer surface of the release piston extension 336 and extend outwardly from the outer surface of the release piston extension 336 to mesh with the rotating ratchet mechanism 340 teeth 344 , 346 . In this embodiment, the lugs 352 move in an upwards and downwards direction in response to the upwards and downwards, as shown by arrows 353 and 355 , respectively, motion of the release piston 317 . FIGS. 17A-17E illustrate the PAV 300 configuration after the last pressurize cycle. The PAV 300 is shown in the unlocked-closed configuration. Fluid pressure on the face 179 of piston cap 166 overrides the compressed spring 154 preventing the closing sleeve 144 from sliding upwardly and opening the fluid ports 133 PAV 300 is opened by bleeding, i.e., reducing, the pressure in the inner bore 351 as shown in FIGS. 18A-18E . When the inner bore 351 pressure is bled off, the compressed spring 154 expands against the lower end of the valve piston 162 forcing the valve piston 162 , and thus the closing sleeve 144 , upwardly until the closing sleeve fluid ports 148 are aligned with the fluid ports 133 opening the valve. When the closing sleeve fluid ports 148 are aligned with the fluid ports 133 , fluid is able to flow from outside the outer housing 101 via fluid flow path 150 formed between the inner housing 130 and the outer housing 101 through the fluid ports 133 to the tubing inner bore 351 . While the methods and apparatus of this invention have been described in terms of various embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods, apparatus and/or processes, and in the steps or in the sequence of steps of the methods described herein without departing from the concept and scope of the invention. More specifically, it will be apparent that certain features which are both mechanically and functionally related may be substituted for the features described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and concept of the invention.

4y

This application is a division of application Ser. No. 08/420,813, filed Apr. 12, 1995, pending. BACKGROUND OF THE INVENTION Commercial purity aluminum is the basis for the majority of the normal aluminum alloys. It is often used without any additions, such as in the production of utensils and foil. The production of metallic aluminum from alumina takes place in electrolytic cells or pots at a temperature of approximately 950° C. Direct current is passed through a current-conducting salt bath in which alumina is dissolved. The bath consists of fused sodium aluminum fluoride (Na 3 AlF 6 ), commonly called cryolite, or a mixture of cryolite and other fluorides. Because alumina dissolves in the salt bath, the electrolysis takes place considerably under the melting point of alumina (about 2150° C.). Aluminum fluoride, lithium fluoride, calcium fluoride or magnesium fluoride can be added to the bath in order to further lower the melting point and/or vapor pressure. The typical electrolytic cell comprises a rectangular steel shell lined with refractory material as heat insulation, which in turn is lined with carbon. Carbon blocks in a bottom of the cell serve as the cathode. The cell holds the fuse salt electrolyte in which alumina is dissolved. Carbon anodes are suspended from above the cell and dip into the bath. When the cell is in operation, the bath is kept molten by the heat generated from the passage of electrical current. The surface is usually crusted over. Alumina is added to the bath as needed by breaking the crust. Under the influence of the electric current, aluminum metal is deposited at the negative pole and, therefore, collects at the bottom of the cell from where it is siphoned periodically. Oxygen is released at the anodes where it reacts with carbon, forming CO and CO 2 . Thus, the anodes and anode bars supporting the anodes in a conventional manner are consumed and must be replaced regularly. It is highly desirable to both prevent anode bars from being consumed rapidly, yet permit rapid restoration, refurbishment and/or replacement when so dictated. Conventional aluminum reduction plants require a large amount of electrical energy, and by extending the life of electrodes or allowing inexpensive refurbishment thereof, electrical costs are maintained sufficiently low to assure the production of commercially competitive aluminum by increasing power efficiency and associated carbon anode efficiency, a reduction in the price of aluminum can be achieved and is, of course, compounded over time. Such savings involve a great deal of money (in the millions) and high anode efficiency is extremely advantageous under present Hall-Heroult cell processes using consumable anodes. SUMMARY OF THE INVENTION The present invention is directed to a novel anode bar for supporting anodes/anode blocks particularly adapted for utilization in present-day Hall-Heroult cell applications for producing molten metal, specifically molten aluminum. The anode bar of the present invention evidences a major breakthrough in productivity and power efficiency in existing cells through innovative anode bar design, better control associated therewith, better heat recovery, more efficient use and conversion of raw materials into a pure aluminum end product, and rapid low cost restoration of partially consumed anode bars. Specifically, the anode bar of the present invention is preferably formed from a copper rod of relatively high electrical conductivity. A metal sleeve of relatively hard electrically conductive material, such as steel, receives an end portion of the copper rod, and a generally annular ring is then slipped over an end of the copper rod. The sleeve has a polygonal opening which matches the polygonal configuration of the copper rod, and the two are united by a weld which generally fills a cavity defined by an axial face of the copper rod and an interior surface defining the polygonal opening of the annular ring. A circumferential weld is also utilized to secure the ring to the sleeve. The latter concentrates electrical power at the end of the copper rod and the ring and efficiently transfers the same through an associated carbon block to the cathode of the cell. Preferably, the anode bar just described is formed in pairs by cutting or slitting the copper rod longitudinally for part of its length and bending cut end portions to define a generally inverted -shaped anode defined by a base, a pair of bridging arms and a shoulder joining each bridging arm to a leg with the legs being generally in spaced substantially parallel relationship to each other. A metal sleeve having a cylindrical opening is slipped over each leg and a ring is then slipped over an end of each leg. Each leg has a polygonal exterior surface which is matched by a polygonal opening in each ring. An axial end face of each leg and the polygonal surface of each ring defines a cavity which is filled by a weld to secure legs and the rings together in intimate high electrically-conductive relationship. A circumferential weld also secures each ring to its sleeve and each sleeve is additionally secured by a weld to its associated bridging arm and to a metal reinforcing bar spanning the distance between the sleeves. Carbonaceous material is molded in a conventional manner to form a carbon block or carbon anode encapsulating major portions of the two sleeves thus completing the totality of the anode which is then used in a conventional manner in a Hall-Heroult aluminum smelting cell. As the carbon of the anode or anode block is progressively consumed, so too might/will the metal rings, the lower end portions of the sleeves and the lower ends of the anode bar legs. However, the consumption/destruction of the ring, sleeve and anode bar leg is reduced tremendously from known anode structures because of (1) the intimate surface-to-surface contact between the exterior polygonal surface of each anode bar leg and its associated ring polygonal opening and (2) the weld within and across these mating polygonal surfaces which collectively define an efficient path of conductivity or electricity flow which is concentrated thereby at the end of each leg, its associated ring and the weld therebetween. Therefore, arcing-over between each rod and its sleeve is virtually eliminated, power is concentrated in the area of the ring and the end of the leg, and conductivity between the latter and the carbon anode or a carbon anode block assures a highly efficient transfer of power to the cell bath. Because of the latter construction, should the ring and/or end of the leg eventually be consumed to a point at which power efficiency transfer is undesirable diminished, the carbon anode block is removed, any consumed portion of the ring and/or lower end portion of the sleeve and/or lower end portion of the leg is removed, via a cutting torch for example, and a "fresh" end of the leg is exposed. Another metal ring having a polygonal opening corresponding to the exterior polygonal configuration of the "fresh" leg is slipped upon the latter, rewelding both axially and circumferentially is effected, and subsequently another carbon anode block is molded thereto. Thus, the original anode bar is relatively inexpensive to manufacture, is very efficient as a power conductor, yet can be quickly and inexpensively restored when partially consumed to a point at which efficiency has diminished below a desired level. With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claims and the several views illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a highly schematic fragmentary sectional view taken through a Hall-Heroult aluminum smelting cell, and illustrates an anode bar of the present invention formed of a generally inverted -shaped configuration defined by a base portion, a pair of bridging arms and a shoulder uniting each bridging arm to a leg with a sleeve and a ring being in externally telescopic relationship to each leg. FIG. 2 is a perspective view, and illustrates several of the anode bars of FIG. 1 which can be collectively molded to a single consumable carbon anode block. FIG. 3 is an enlarged fragmentary vertical cross-sectional view taken generally through the right-hand leg, sleeve and ring of the anode bar of FIG. 1, and illustrates details of the construction thereof. FIG. 4 is a cross-sectional view taken generally along line 4--4 of FIG. 3, and illustrates the bridging arm received in an upwardly and radially opening slot or notch of the sleeve and an associated T-shaped reinforcing member. FIG. 5 is an exploded view, and illustrates the anode bar components, namely, the inverted -shaped copper rod, one cylindrical sleeve having a cylindrical opening, and an annular ring having a polygonal opening matching the polygonal exterior configuration of the copper anode leg. DESCRIPTION OF THE PREFERRED EMBODIMENTS An electrolytic Hall-Heroult smelting cell for commercially producing aluminum from alumina is illustrated in FIG. 1 of the drawings and is generally designated by the reference numeral 10. The electrolytic cell or pot 10 is defined by an exterior steel shell 11 lined internally with insulation 12. A cathode bar 13 is connected to the negative side of a source of electrical power (not shown) and lies beneath a carbon cathode 14. A port (not shown) is provided through which molten aluminum A is periodically siphoned. Molten alumina and cryolite form a conventional electrolyte or an electrolyte bath E within which is at least partially immersed one or more consumable carbon anodes or carbon blocks C with the carbon anode C having cylindrical blind end cavities Ca, Ca'. Solidified alumina and cryolite S forms a crust. The steel shell 11 of the electrolytic cell 10 is covered by a conventional gas collection hood H. Electricity is conducted to the carbon block C by a novel anode bar or anode support of the present invention which is generally designated by the reference numeral 20 and is specifically adapted for utilization during the production of molten alumina by the Hall-Heroult process. The anode bar 20 includes a bar or member 21 which originally is a straight length of highly electrically conductive material, such as copper, having a generally rectangular configuration, as is readily apparent from FIGS. 2 and 5. Originally, the rod 21 is approximately 98 inches in length and is of a polygonal configuration of approximately 3"×3". This copper rod is slit medially along its longitudinal axis from one end a distance of approximately 26 inches and is then bent to the generally inverted -shaped configuration illustrated best in FIGS. 1, 2 and 5 of the drawings. The inverted -shaped rod is defined by a relatively long (72 inches) base portion or connecting portion 22 having an opening 23 for connection to a conventional anode beam B; bridging arms or bridging portions 24, 24 joined by inner shoulders or radius portions 25 to the base portion 22; outer shoulders or radius portions 26 joined to the bridging arm portions 24, and depending leg portions 27 which are in generally parallel relationship to each other and terminate in axial end faces or surfaces 28. A pair of identical relatively hard metallic sleeves 30, such as steel, which are also highly electrically conductive, are each defined by an outer cylindrical surface 31 (FIG. 5), an inner cylindrical surface 32, a lower annular axial end face or surface 33, a chamfer 34 between the surfaces 31, 33, an upper annular axial end or surface 35 and a notch 36 which opens axially through the upper annular end surface 35 and radially through the cylindrical surfaces 31, 32. The diameters of the surfaces 31, 32 are 6" and 3", respectively. Therefore, each leg 27 can be freely telescopically inserted into each sleeve 30, as is best illustrated in FIG. 3, and when so inserted, each arm portion 24 is snugly accommodated in one of the slots 36. Suitable welds W1 (FIGS. 3 and 4) are utilized to weld each steel sleeve 30 to its associated bridging arm portion 24 along the underside (unnumbered) and the side edges (also unnumbered) of the notch 36 to rigidly unify each leg 27 to its associated cylindrical sleeve or stub 30. At this stage in the fabrication of the anode bar 20 the terminal end portion or axial end face 28 of each leg 27 projects beyond the lower annular axial end face 33 of each sleeve 30, as is most readily apparent from FIGS. 3 and 4 of the drawings. A generally annular metallic ring 40 constructed from relatively hard electrically conductive material, such as steel, has a polygonal opening 41 corresponding in shape and size to the exterior polygonal configuration of each leg 27. Each polygonal opening 41 is defined by a generally polygonal surface 42 (FIG. 5) which matches the exterior polygonal surface (unnumbered) of each of the legs 27 and which merges with a chamfered polygonal surface 43. The chamfered surface 43 terminates at a lower, generally annular, end face or axial surface 44 which is spaced from and is generally parallel to an upper annular end face or axial surface 45 (FIG. 3) between which is a cylindrical surface 46 having an exterior diameter matching the diameter of the exterior surface 31 of each sleeve 30. A peripheral chamfer or chamfered surface 47 lies between the surfaces 45, 46 and matches the chamfer 34 of each sleeve 30. Each ring 40 is slipped upon one of the legs 27 with each leg 27 being in intimate surface-to-surface contact with the polygonal surface 42 thereof, as is most apparent from FIG. 3. In this position the axial face 28 of each leg 27 is set back from the lowermost end face 44 of each ring 40, as is best illustrated in FIG. 3. The end face 28 of each leg 27 and the chamfer 43 define a cavity or well 50. The end of each leg 27 is welded to the annular ring 40 throughout the entire area of the cavity 50 by a weld W2 which essentially covers the entire end face 28 of each leg 27 and forms an intimate bond between the polygonal surface of each leg 27 and the polygonal surfaces 42, 43 of its associated ring 40, as is best illustrated in FIG. 3. A weld W3 is provided between the chamfered surfaces 34, 45 to unite each ring 40 to each sleeve 30. Reinforcing means 60 in the form of a generally T-shaped member constructed from relatively strong electrically conductive material, such as steel, bridges the distance between each of the sleeves 30, 30 (FIG. 2) along the underside of the arm portions 24, 24 thereof. The reinforcing means or member 60 is defined by a generally horizontal portion or land 61 and a downwardly projecting vertical portion or rib 62 located substantially half the distance between ends (unnumbered) of the horizontal portion 61, as is best illustrated in FIG. 4. An upper surface (unnumbered) of the horizontal portion 61 underlies and preferably abuts a lower surface (unnumbered) of the bridging arm or bridging arm portions 24, 24. Welds W4 (FIG. 4) weld an upper side (unnumbered) of each horizontal portion 61 to each sleeve 31 and welds W5 weld a lower side (unnumbered) of each horizontal portion 61 to each sleeve 30. A weld W6 along vertical sides and a lower edge (unnumbered) of the vertical portion 62 of each reinforcing member 60 welds the vertical portion 62 thereof to each of the sleeves 30. The anode bar 20 can now be fused singularly, in pairs, or in groups, as shown in FIG. 2, relative to an associated carbon block or carbon anode C by molding carbonaceous material thereto in the manner illustrated in FIG. 1. Thereafter, the base portions or connecting portions 22 are secured by suitable fasteners, such as bolts and nuts (not shown) to one or more conventional anode beams B (FIG. 1) which are in turn connected to a positive source of electrical power with, of course, the cathode bar 13 being connected to a negative source of electrical power, as earlier described. During electrolysis in the electrolytic cell 10, the carbon block(s) or anode(s) C is immersed in the electrolyte bath E which is kept molten by the heat generated from the passage of electrical current. Under the influence of the electrical current, the molten aluminum A is deposited adjacent the carbon cathode 14 at the bottom of the electrolytic cell 10 from where it is siphoned periodically through a conventional port (not shown), as was heretofore described. Oxygen is released at the carbon block C and at the anode bar 20 where it reacts with carbon forming CO and CO 2 , and though the latter is exhausted from beneath the hood H, the anodes C are continuously and progressively consumed and must be replaced regularly. Consumption of the carbon blocks C is dramatically reduced by the present invention because of the construction of the anode bar 20 heretofore described, particularly because of the intimate engagement between each annular ring 40 and the associated end 28 of each leg 27 by virtue of (a) the matching polygonal configuration of the exterior surface of each leg 27 and the interior polygonal surface 42 of each ring 40 and (b) the intimate weld W2 (FIG. 3) which fills the cavity 50, covers the end face 28 of each leg 27, and intimately unites the chamfer surface 42 of each annular ring 40 to the end of each leg 27. Due to the latter construction, current which flows through each bridging arm portion 24, 24, each shoulder 26 and each leg 27 and each sleeve 30 and ring 40 will not disadvantageously arc, particularly across the gap between each leg 27 and the interior cylindrical surface 32 of each sleeve 30, but will instead pass through each leg 27, axially through each end face 28 and the associated weld W2 and through each annular ring 40 and the associated carbon block C. Therefore, the current flow is extremely efficient absent undesired arcing and the cost of aluminum in pounds per cell day is dramatically reduced. Moreover, as the carbon block C is consumed, so too are surface portions of the sleeves 30, the rings 40 and the welds W2, W3 associated therewith. However, before efficiency is noticeably decreased due to carbon block, sleeves/rings and or weld consumption, it should be particularly noted from FIG. 3 that each anode leg 27 is protected by the hard steel of the sleeve 30 and ring 40 and the material of the welds W2, W3, and it is not until the latter components have deteriorated appreciably, that the softer copper of the legs 27 can be subject to deterioration. However, should any of the latter substantially occur, restoration is readily and inexpensively achieved by removing the anode bar 20 from the cell 10, breaking the remaining carbon block C associated therewith, and burning/torching off whatever might remain of the ring 40 and/or the sleeve 30. For example, in FIG. 3 a dashed line has been added and is identified by the reference character D to designate outermost portions of the sleeve 30, the annular ring 40 and the leg 27 which may be consumed during the smelting process. The metal to the left and right of the dashed lines associated with the sleeve 30 and beneath the ring 40 and the end of the leg 27 represents metal which has been consumed. Obviously, the welds W2 and W3 are consumed and are thus nonexistent, and the remaining portion of the ring 40 (above the dashed line D) might well simply fall from the remaining end portion of the leg 27. However, if such does not occur or if the welds W3 have not been consumed, these welds W3 can be burned off, and the remaining portions of the annular ring 40 can be removed. Furthermore, the lower end portion of the sleeve 30 which has been consumed can also be burned away as might be an end of the remainder of the leg 27. At this point, a new ring 40 is slipped upon the leg 27 and secured thereto by welds corresponding to the welds W2, W3. Therefore, by constructing the sleeve 30 of a relatively long length (12 inches, for example), the same can be restored as its lower end portion is consumed by merely cutting away progressively consumed bottom portions thereof and welding thereto new annular rings. An anode bar 20 thus restored when remolded to a carbon block C is just as efficient as when initially fabricated. Accordingly, the anode bar 20 of the present invention is extremely efficient from the standpoint of (a) initial fabrication, (b) use, (c) restoration and (d) reuse. It should also be particularly noted that since the copper member 21 initially is slit or cut along its longitudinal axis to form the bridging arm portions 24, 24, the entirety of the member 21 is of a single one-piece homogeneous construction which facilitates current flow in as efficient a manner as possible. Thus, arcing between the anode beam B and the cathode bar 13 along the flow path defined by the anode bar 20 is virtually totally eliminated rendering the electrolytic process extremely efficient. Although a preferred embodiment of the invention has been specifically illustrated and described herein, it is to be understood that minor variations may be made in the apparatus without departing from the spirit and scope of the invention, as defined the appended claims.

4y

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Not Applicable. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable. APPENDIX [0003] Not Applicable. BACKGROUND OF THE INVENTION [0004] 1. Field of the Invention [0005] This invention pertains to collapsible shelters, such as tents, canopies, and sun-shades. More particularly, the present invention pertains to a hub for connecting support poles of a shelter in a manner such that the poles that are directly attached to the hub are not all rigidly connected to each other. [0006] 2. General Background [0007] Collapsible shelters, such as tents, canopies, and sun-shades often comprise a pliable shell supported by a plurality of structural poles that can be selectively detached from each other, or otherwise collapsed, in a manner such that the shelter can be selectively erected and, alternatively, collapsed. In some cases, the structural assembly of poles is configured to be separated from the pliable shell as the shelter is being collapsed. More recently, it is becoming common to configure a collapsible shelter such that its structural poles remain connected to each other and to the pliable shell of the shelter when the shelter is collapsed. [0008] There are two very common types of pole assemblies used in connection with collapsible shelters. One type utilizes a plurality of poles that are held together via an elastic cord (often called shock cord) that passes longitudinally through the hollow centers of a plurality of poles in a manner such that socket fittings are sufficient to maintain the poles in an erected configuration. Another type utilizes poles that are hinged or telescoping. In general, the former is lighter than the latter and the latter is generally more rigid and strong. The present invention can be used in connection with either type of pole assemblies. [0009] Although the assembly of poles provides support for the pliable shell, in many cases the pliable shell of the shelter works in concert with the assembly of poles to structurally support the shelter in its erected configuration. In other words, the pliable shell of a collapsible shelter often serves as tension and shear panels that prevent the pole assemblies from buckling or twisting. Thus, the pole assemblies need not be self-supported. [0010] In an effort to reduce the weight of collapsible shelters to facilitate the transportation of such shelters, the structural poles are typically minimally sized for anticipated load requirements. As a result, the fittings and other components that connect the poles to each other in their erected configuration, and the poles themselves, can experience high bending stresses. This can lead to component failure or fatigue. SUMMARY OF THE INVENTION [0011] The present invention pertains to a hub that is configured and adapted to connect at least two pairs of poles to each other in a manner such that the pairs of poles are able to pivot relative to each other, while each pair of poles remains generally rigid. By allowing the pairs of poles to pivot relative to each other, bending loads on the hub are reduced, and the pliable shell of the shelter is able to more efficiently transfer load from pair to pair. This also allows collapsible shelters to more easily accommodate and absorb wind and impact loads. Still further, the pivotal nature of the hub allows a collapsible shelter to be collapsed and erected with greater ease. [0012] In one aspect of the invention, a hub and pole assembly for a collapsible shelter, such as a tent, canopy, or sun-shade, comprises first and second hub portions that are connected to each other in a manner such that the first and second hub portions are pivotal relative to each other generally about a hub axis. The hub axis generally defines circumferential, axial, and radial directions. The first hub portion attaches a first set of at least two poles to each other in a manner such that the first set of poles maintain their circumferential spacing about the hub axis. The second hub portion attaches a second set of at least two other poles to each other in a manner such that the second set of poles maintain their circumferential spacing about the hub axis. The pivotal connection between the first and second hub portions allows the first set of poles to pivot about the hub axis relative to the second set of poles. [0013] In another aspect of the invention, a pole hub assembly for a collapsible shelter, such as a tent, canopy, or sun-shade, comprises first and second crossmembers and a plurality of pole attachment portions. The first and second crossmembers are attached to each other in a manner such that the first and second crossmembers can pivot relative to each other generally about a hub axis and in a manner such that the first and second crossmembers crisscross each other. The hub axis generally defines radial and axial directions. Each of the first and second crossmembers has opposite end portions, each of the end portions has a respective one of the pole attachment portions pivotally attached thereto in a manner such that the respective pole attachment portion is pivotal about a respective pole attachment axis that is generally perpendicular to both the radial and axial directions. Each of the pole attachment portions comprises a socket that is adapted and configured to receive an end of a tent-type pole. [0014] In yet another aspect of the invention, a collapsible shelter comprises a pliable shell supported by a pole assembly. The pole assembly comprises a first pair of poles and a second pair of poles. The poles of the first pair of poles are connected to each other via a first portion of a hub in a manner defining a first assembly. The poles of the second pair of poles are connected to each other via a second portion of the hub in a manner defining a second assembly. The first and second portions of the hub are pivotally connected to each other generally about a hub axis. The poles extend from the hub in a manner such that the first assembly crisscrosses the second assembly. The pivotal connection between the first and second hub portions allows the first and second assemblies to pivot as separate units relative to each other about the hub axis. [0015] Further features and advantages of the present invention, as well as the operation of the invention, are described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 depicts a perspective view of a hub and pole assembly in accordance with the invention, and is shown with the first and second portions of the hub at one of their two limits of pivotal travel. [0017] FIG. 2 depicts another perspective view of the hub and pole assembly shown in FIG. 1 , showing the first and second portions of the hub at the other limit of pivotal travel. [0018] FIG. 3 depicts the hub and pole assembly shown in FIGS. 1 and 2 in its partially collapsed configuration. [0019] FIG. 4 is an assembly view of the hub and pole assembly shown in FIGS. 1-3 . [0020] FIG. 5 depicts a collapsible tent that comprises the hub and pole assembly shown in FIGS. 1-4 . [0021] Reference numerals in the written specification and in the drawing figures indicate corresponding items. DETAILED DESCRIPTION [0022] A preferred embodiment of a hub and pole assembly ( 10 ) in accordance with the invention is shown by itself in FIGS. 1-4 . The hub and pole assembly ( 10 ) comprises a hub ( 12 ) and a plurality of poles ( 14 ) attached thereto. [0023] The hub ( 10 ) comprises first and second portions ( 16 , 18 ) that are pivotally connected to each other about a hub axis. Preferably, the first and second portions ( 16 , 18 ) are each a crossmember that crisscrosses the other crossmember. To minimize the thickness of the hub ( 12 ) without significantly impacting the strength and stiffness of the crossmembers ( 16 , 18 ), the first crossmember ( 16 ) comprises an opening ( 20 ) through which the second crossmember ( 18 ) extends. A central screw ( 22 ) is aligned with the hub axis and extends through the first and second crossmembers ( 16 , 18 ). A nut ( 24 ) secures the central screw ( 22 ) to the first crossmember ( 16 ) and the central screw ( 22 ) serves as an axle about which the second crossmember ( 18 ) can pivot. The opening ( 20 ) of the first crossmember ( 16 ) is preferably dimensioned such that the second crossmember ( 18 ) is pivotable through a range of slightly less than sixty degrees relative to the first crossmember ( 16 ). In the middle of its pivotable range, the second crossmember ( 18 ) preferably extends longitudinally at ninety degrees from the longitudinal direction of the first crossmember ( 16 ). FIGS. 1 and 2 depict the two extremes of the pivotal nature between the first and second crossmembers ( 16 , 18 ). The first crossmember ( 16 ) also preferably comprises a pair of oppositely projecting wings ( 26 ) that extend outwardly adjacent the opening ( 20 ) of the first crossmember. The wings ( 26 ) help prevent pliable shell material from interfering with the pivotal nature of the hub ( 12 ) when, as shown in FIG. 5 , the hub and pole assembly ( 10 ) is attached to a pliable shell ( 28 ) to form a collapsible shelter ( 30 ) . [0024] The hub 12 also preferably comprises a plurality of pole attachment portions ( 32 ) that connect the poles ( 14 ) to the crossmembers ( 16 , 18 ). The pole attachment portions ( 32 ) preferably are pivotally attached adjacent the longitudinal ends of crossmembers ( 16 , 18 ) via screws ( 34 ). Preferably, the screws ( 34 ) are oriented perpendicular to the radial and axial directions defined by the central screw ( 22 ) of the hub ( 12 ). Each pole attachment portion ( 32 ) also preferably comprises a socket ( 36 ) configured to receive the end of the pole ( 14 ), which is preferably press fit or adhered into the socket such that it cannot easily be removed therefrom. Each of the longitudinal ends of each of the crossmembers ( 16 , 18 ) preferably comprises a pivot-stop ( 38 ) that is configured to engage and abut the respective pole attachment portion ( 32 ) in a manner preventing the pole attachment portion from pivoting beyond a particular limit. When a collapsible shelter ( 30 ) comprising the hub and pole assembly ( 10 ) is in its erected configuration, each pole attachment portion ( 32 ) is biased against and firmly engages its respective pivot-stop ( 38 ). [0025] The hub and pole assembly ( 10 ) of the preferred embodiment is particularly configured to serve as a roof hub and pole assembly of a collapsible shelter ( 30 ), as shown in FIG. 5 . Each pole ( 14 ) that is attached to the hub ( 12 ) is preferably one of several poles that together constitute one of several legs ( 40 ) of the collapsible shelter ( 30 ). As shown in FIG. 5 , each leg ( 40 ) of the collapsible shelter ( 30 ) passes through several loops ( 42 ) that are connected to the pliable shell ( 28 ) of the shelter. Each leg ( 40 ) preferably comprises two telescopically attached pole sections ( 44 ) that extend primarily vertical. Each leg ( 40 ) also preferably comprises an elbow joint ( 46 ) that pivotally connects the upper one of the telescopically attached pole sections ( 44 ) to the pole ( 14 ) of the leg that is connected to the hub ( 12 ). Like the crossmembers ( 16 , 18 ) of the hub ( 12 ), each elbow joint also comprises pivot-stops that prevent the included angle between the telescopically attached pole sections ( 44 ) and the pole ( 14 ) of the respective leg ( 40 ) from decreasing beyond a particular amount, such as that shown in FIG. 5 . In view of the foregoing, it should be appreciated that when the collapsible shelter ( 30 ) is in its erected configuration (as shown in FIG. 5 ), each leg ( 40 ) is generally rigid. In other words, the leg ( 40 ) can resiliently flex but it will not pivot at its elbow joint ( 46 ) or relative to the respective crossmember ( 16 or 18 ) that it is attached to because the pliable shell prevents it from doing so. Thus, it follows then that the two or more legs ( 40 ) that are attached to a particular one of the crossmembers ( 16 , 18 ) of the hub ( 12 ) together also act as a generally rigid unit. Notably however, due to the pivotal nature of the hub ( 12 ), such legs ( 40 ) are able to pivot about the hub axis relative to the two or more legs ( 40 ) that are attached to the other of the crossmembers ( 16 , 18 ). [0026] When the collapsible shelter ( 30 ) is collapsed, the poles ( 14 ) attached to the crossmembers ( 16 , 18 ) pivot about the screws ( 34 ) that secure the pole attachment portions ( 32 ) to their respective crossmember, as shown in FIG. 3 . The telescopically attached pole sections ( 44 ) can also be collapsed and the leg can be folded in over itself via the elbow joint ( 46 ) that pivotally connects the upper one of the telescopically attached pole sections ( 44 ) to the pole ( 14 ) of the leg. Thus, the hub and pole assembly ( 10 ) allows the collapsible shelter ( 30 ) to be stored or transported compactly. [0027] In view of the foregoing, it should be appreciated that the invention has several advantages over the prior art. [0028] As various modifications could be made in the constructions and methods herein described and illustrated without departing from the scope of the invention, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative rather than limiting. Thus, the breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims appended hereto and their equivalents. [0029] It should also be understood that when introducing elements of the present invention in the claims or in the above description of exemplary embodiments of the invention, the terms “comprising,” “including,” and “having” are intended to be open-ended and mean that there may be additional elements other than the listed elements. Additionally, the term “portion” should be construed as meaning some or all of the item or element that it qualifies. Moreover, use of identifiers such as first, second, and third should not be construed in a manner imposing any relative position or time sequence between limitations. Still further, the order in which the steps of any method claim that follows are presented should not be construed in a manner limiting the order in which such steps must be performed, unless such and order is inherent.

4y

CROSS-REFERENCE TO RELATED APPLICATION The present application is a continuation-in-part of application Ser. No. 10/930,148 filed on Aug. 31, 2004, which claims the benefit of U.S. Provisional Application No. 60/503,033 filed Sep. 15, 2003. In addition, this application is a continuation-in-part of application Ser. No. 10/764,245 filed on Jan. 23, 2004, which claims the benefit of U.S. Provisional Application No. 60/442,446 filed Jan. 25, 2003. All of the prior applications listed in this paragraph are hereby incorporated by reference in their entirety. BACKGROUND The present invention relates to septic systems and to the components that make up such systems. More particularly, it relates to an improved method and apparatus for remediating the formation of a bio-mat that can occur in the absorption field component of a private on-site wastewater treatment system. Septic systems and septic system components are well known in the art. Such systems are typically found in relatively sparsely populated areas not otherwise serviced by municipal waste water systems. The purpose of a septic system is to dispose of the wastewater that is generated by the occupants of a home or other building in such a manner that surrounding soils can be used to disperse the wastewater without causing an adverse effect on ground water and, in turn, on public health and the environment in general. To accomplish this task, septic systems are normally comprised of a septic tank, a distribution system and a leaching system. The septic tank is connected to the plumbing of a home or building by means of a sewer line. The septic tank provides a holding area for the settling of waste solids and for some initial treatment of the waste. Generally, septic tanks have baffles to slow the velocity of the liquid moving through the tank and to prevent solids from leaving the tank. In this way, properly functioning septic tanks produce an effluent of fairly uniform quality. The effluent then moves to a distribution system that directs the flow of effluent from the septic tank to the leaching system in such a manner as to fully utilize the leaching system. Most systems take advantage of gravity, meaning that flow runs through piping and distribution boxes without the assistance of any mechanical device such as a pump. The leaching system disperses the sewage effluent over a given underground area and into the surrounding natural soils. There are several types of leaching systems and the specific type used often depends on the surrounding soil conditions. Most residential leaching systems use stone filled leaching trenches but galleries, pits, and beds have also been used. In the experience of this inventor, private on-site wastewater treatment systems have finite lifetimes due to many factors including household water use, excessive introduction of chemicals into the waste stream, poor maintenance, and environmental factors. Replacement of any septic system component that may be required to deal with remediation of the entire system can be extremely expensive. The reason for this is the fact that the septic system components, for the most part, are buried underground as previously described and are largely inaccessible. A very significant factor is that passive septic systems typically rely on the presence of indigenous anaerobic bacteria to break down the solid waste introduced to the system. As solid waste enters the septic tank, it flows through the series of baffles that are designed to reduce the velocity of the flow as previously described. Generally, three identifiable layers occur in a septic tank. First, as designed, solid wastes precipitate out of the flow to the bottom of the septic tank. This layer is generally known as sludge. Liquid effluent is the intermediate layer and generally consists of liquids and solids partially broken down into liquids by the anaerobic bacteria that are present in the septic tank. This intermediate layer is drained off to the absorption field. The top layer in the septic tank is generally known as the scum layer. The scum layer is comprised of mostly residual detergents, soaps, fats and oils and has a tendency to float at the top of the septic tank. Optimally, the septic tank is designed such that only the partially treated liquid effluent is permitted to leave the septic tank for the absorption field. Unfortunately, this is not always the case. The standard septic system is passive in that it relies on the presence of indigenous anaerobic bacteria to break down the solid wastes introduced into the system. Anaerobic bacteria thrive in conditions such as those that exist at the bottom of a septic system, where oxygen is lacking. Accordingly, septic systems are designed to have the capacity to treat a certain amount of solid wastes based on the capability of the indigenous bacteria to break down the solid waste over a certain period of time. Therefore, the average amount of solid waste produced per day should be approximately equal to the amount that the anaerobic bacteria can break down in one day. Aerobic bacteria are also indigenous and occur naturally within the waste stream. Aerobic bacteria, however, exist and function only where oxygen is present. While aerobic bacteria typically break down solid wastes more quickly than anaerobic bacteria, they are ineffective at breaking down sludge, or the solid layer at the bottom of the septic tank, because there is no oxygen present in that layer. Due to increased installation and operating costs, aerobic systems that would otherwise eliminate this sludge layer are not favored for home use. As anaerobic bacteria digest solids suspended in the effluent as they make their way to the absorption field or in the absorption field, the suspended solids and accompanying bacteria are then deposited at the interface between the absorption field and the soil surrounding the system. This layer is known as the “bio-mat” and it performs further filtering of the effluent. Unfortunately, the bio-mat layer can grow to a thickness where it completely, or almost completely, impedes absorption. While there are many ways in which septic systems can fail, two of the most likely modes of failure include the creation and thickening of a bio-mat layer at the absorption field component of the system due to the decomposition of solids within the effluent. Excess sludge and scum from the septic tank can also build up in this bio-mat. For example, when the rate of decomposition caused by the anaerobic bacteria is incapable of keeping up with rate of solids draining into the system, the septic tank fills with sludge. As the sludge level gets higher, the scum level at the top of the tank takes up more space. This causes the liquid effluent to run through the septic tank more quickly, which prevents solids from settling. The solids that fail to settle in the septic tank proceed to the absorption system, where they frequently plug the pores in the soil used for absorption. The scum layer can also find its way out of the septic tank and similarly prevents soil absorption. And if too much of the absorption field is plugged by scum and solids, the effluent will actually back up in the absorption area and cause muddy spots in the area above the absorption field. This is a sign that the absorption field has failed, an extremely malodorous and unsightly condition. As alluded to earlier, replacement of soil absorption systems is frighteningly costly and heavily regulated by states, counties and municipalities due to the threat that malfunctioning systems pose to the groundwater. Replacement systems are very expensive, with the actual expense depending on the condition of other components in the septic system. Some owners chose to convert their existing passive system to an active system, an even more costly endeavor. Another possible option is to create an above-grade soil absorption system. Above grade systems also have operating—and maintenance expenses and those are even greater than passive systems. Holding tanks are frequently the option of last resort as they are also expensive and need to be regularly pumped by a commercial contractor. Frequently, a failing or failed soil absorption system can be remediated with the support of naturally occurring aerobic bacteria in the system. In theory, an aerobic system could eliminate or substantially reduce the failure rate of an absorption-field. Unfortunately, aerobic bacteria also require the introduction of oxygen into the waste stream. This inventor has previously identified a need for a temporary means for introducing oxygen into a failed or failing soil absorption field for the purpose of converting the biochemical process from an anaerobic one to an aerobic one. In U.S. patent application Ser. No. 10/764,245, this inventor disclosed that a forced introduction of oxygen into the system would allow the aerobic bacteria to scour the bio-mat, thereby working to reduce the thickness and/or increase the permeability of the bio-mat and permit the system to revert back to an anaerobic passive system as originally designed. There is also a need to alter the biochemical process by conversion of the complete soil absorption component or a localized area of it. This inventor has also found that the forced introduction of ozone gas can improve performance of the remediation process disclosed above. Ozone, also known as triatomic oxygen or O 3 , is itself a powerful oxidizing agent. In nature, ozone is created when the electrical current of lightning transforms diatomic oxygen molecules, or O 2 , into activated triatomic oxygen, or O 3 . Ozone, however, is also an unstable gas which, at normal temperatures and under all ordinary conditions, spontaneously decomposes to diatomic oxygen or O 2 . This decomposition is speeded by solid surfaces and by many chemical substances. For this reason, ozone is not encountered except in the immediate vicinity of where it is formed. That is, ozone cannot be stored and must be generated on-site. When ozone is introduced into the system, some of the highly oxidizing agent decomposes bio-degradable matter in the system. The balance of the available ozone rapidly decomposes to oxygen and is available for consumption by the aerobic bacteria. SUMMARY The present invention provides a portable wastewater treatment system comprising a wastewater holding tank having an interior adapted to hold wastewater, and a generator positioned to provide ozone, oxygen, or a combination of the two to the interior of the holding tank. In one embodiment, the holding tank comprises a gray-water tank, and the system further comprises a non-potable water tank having an interior. In this embodiment, the system further includes a second generator positioned to provide ozone, oxygen, or a combination of the two to the interior of the non-potable water tank and a conduit coupling the gray-water tank to the non-potable water tank. The system can further include a black-water tank having an interior, a third generator positioned to provide ozone, oxygen, or a combination of the two to the interior of the black-water tank, and a conduit coupling the black-water tank to the non-potable water tank. The system can further include a toilet having an inlet and an outlet, a first conduit coupling the non-potable water tank to the inlet of the toilet, and a second conduit coupling the outlet to the black-water tank. The system can also include a potable water tank, a point of water usage coupled to the potable water tank, and a fourth generator positioned to provide ozone, oxygen, or a combination of the two to the potable water tank. The above system can be used to treat wastewater in a portable system, such as might be found in a vehicle or portable restrooms. Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a typical private wastewater treatment system of the type that the method and apparatus of the present invention could be used with. FIG. 2 is a top plan view of the system illustrated in FIG. 1 . FIG. 3 is a side elevational view of the system shown in FIG. 1 . FIG. 4 is a perspective view of the components of an apparatus constructed in accordance with the present invention. FIG. 5 is a graph of ponded effluent depth versus elapsed time in a typical application using the method and apparatus of the present invention. FIG. 6 is a schematic diagram of a portable tank wastewater treatment system with optional water recycling. FIG. 7 is the system of FIG. 6 implemented in a vehicle. DETAILED DESCRIPTION Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings. Reference is now made to the drawings wherein like numbers refer to like elements throughout. FIG. 1 illustrates a septic system, generally identified 10 with which the improved apparatus and method of the present invention is intended to be used. It is to be understood, however, that the precise configuration of the improved system is not a limitation of the present invention and could assume any number of sizes and layouts. The septic system 10 shown is for illustration purposes only. A six foot tall man 4 is included for relative size reference as well. As shown in FIG. 3 , the septic system 10 lies, for the most part, below earth grade 2 . The system 10 includes a pipe 12 leading from a home or building (not shown) which pipe 12 is connected to a first septic tank 14 . The first tank 14 may or may not have a vented cover. As shown, the first tank 14 includes a riser 16 . The first tank 14 is, in turn, connected to a second tank 18 . This second tank 18 may or may not have a vented cover as well. As shown, the second tank 18 includes a riser 20 and a vent 21 . As will become apparent later in this detailed description, if either the first or second tanks 14 , 18 do not have a vented cover atop of 16 , 20 , respectively, one may need to be added in order to utilize the apparatus of the present invention. This second tank 18 may also be a pumping chamber. It should also be noted that the second tank 18 lies slightly below the first tank 14 such that gravity affects a downstream flow of effluent from one tank to the other. The second tank 18 is, in turn, connected to a dry well or seepage pit 22 . The dry well or seepage pit 22 includes a vent 24 . An alternate to a dry well or seepage pit 22 is an absorption field 26 or an above grade mound system (not shown). The absorption field 26 may include a distribution box 28 and a vent 30 . The distribution box 28 of the absorption field 26 may or may not include a distribution box riser 32 and a distribution box vent 34 . Again for reasons that will become apparent later in this detailed description, a distribution box riser 32 will likely need to be added to the system 10 if one is not already included. As shown in FIG. 3 , it will be shown that the downward flow of effluent is affected by gravity. Alternatively, the effluent can be moved by a positive pressure pump to the soil distribution component of the system. In general, the improved apparatus of the present invention is comprised of at least one high volume ozone-generating pump 40 connected to at least one low pressure drop sintered air stone 60 . The air stone 60 has a relatively large surface area, See FIG. 4 . The pumps 40 and all internal electrical connections are packaged in a weatherproof container 42 . The external electrical connection 44 is connected via an extension cord to a circuit breaker or may be permanently hardwired to an electrical junction box. The pumps 40 force oxygen and ozone, or ozone only, into clear vinyl tubing 50 , although many types of tubing are acceptable and would be within the scope of the present invention. The tubes, or aeration lines, 50 are then connected to the air stones 60 , which are placed at various locations inside the septic system 10 . It is to be understood that at least one high volume ozone-generating pump 40 be utilized to introduce ozone into the system. Other pumps 40 may be used with or without ozone-generating capabilities. As shown in FIG. 1 , and using the improved system illustrated therein as representative of a typical system, the preferred location for the aeration lines 50 is in the vent pipe 34 of the distribution box 28 , the vent pipe 24 of the dry well 22 , or the vent pipe 21 of the second tank or pumping chamber 18 . For example, as shown in FIGS. 1 , 2 and 3 , a first pump 40 a , tubing 50 a , and air stone 60 a are used with the second tank 18 . At that location, the first air stone 60 a and a portion of the tubing 50 a are inserted into the second tank 18 via the tank vent 21 . A second pump 40 b , tubing 50 b , and air stone 60 b are used with the dry well or seepage pit 22 , and a third pump 40 c , tubing 50 c , and air stone 60 c are used with the distribution box 28 of the absorption field 26 . If the standing effluent level in the distribution box 28 is not of adequate depth, an alternate location should be considered. If a vent pipe or well is not available at this location, one may be installed for a rather nominal cost. In most cases, the standard vent cap can be used during remediation. It is to be understood that the improved apparatus of the present invention could be installed in alternate locations. For example, the aeration lines could be installed in the final septic tank or pumping chamber of a multiple tank system or in the septic tank in a single tank system immediately prior to the outlet to the soil absorption system. As an alternate to installing through a vented cover, small holes can be drilled through the lid of the tank or compartment and the aeration lines installed. Installation of an approved effluent filter is recommended with this application method. Remediation is a lengthy process. However, the improved method, and apparatus of the present invention provides some degree of immediate relief quite quickly. Thereafter, the rate of remediation tapers off over time. Substantial remediation can occur in most systems within about 6 months, although other systems may require as long as one year. If, even then, the system is not completely remediated, the equipment can be operated for longer periods without detrimental effects to the system. One advantage to the use of at least one ozone-generating pump 40 within the system is that the application of ozone to any medium, liquid or gas, does not add other chemicals to the system. Depending on conditions, the introduction of ozone, approved bacteria, enzymes and vitamins may expedite the remediation process. Unfortunately, after the remediation equipment has been removed, there will be a lag of decomposition activity while the aerobic bacteria die and the anaerobic bacteria again takes over. Many types of bacteria are available for purchase which include both aerobic, and or anaerobic and or facultative that can expedite the system's return to normalcy. Addition of these products is not required in the improved method of the present invention but may be considered to enhance performance. In the experience of this inventor, the length of time required to remediate a failing or failed absorption field depends on several factors, including, but not limited to, system type, size, severity of failure, site conditions, precipitation, and the average temperature during the remediation process. Several trials have been conducted that show the influences of these conditions. All trials showed successful application of the remediation program. The trials showed little change in measured effluent in the absorption system during the first several days of remediation. The following weeks showed a significant drop in effluent levels. Over time, the rate of effluent reduction decays. Rapid effluent drop near the top of the absorption system is to be expected as it is not normally used until the lower levels become plugged and the effluent levels begin to rise. Daily specific hydraulic loading and local precipitation had similar effects on all systems. In another particular application, the present invention provides for use of one Enaly OZX-1000U ozone generator 40 , two 12 inch Micro-Bubble air stones 60 , 20 feet of tubing 50 , a pair of “tees”, one tube weight, a weatherproof container 42 , an extension cord 44 and a UL rated ground fault circuit interrupter, or GFCI. See also FIG. 4 . All electrical connections for the generator 40 are located inside the weatherproof container 42 . An extension cord runs to a GFCI and then to the power source. The generator 40 used in this embodiment of the invention provides an ozone output of 1000 mg/hour with a pump output of 4 to 5 liters per minute, although other generators of various output capacities could be used. Other sizes and types of tubing 50 would also work equally well. Additionally, several types of air stones 60 other than that specified will work. The air stones 60 are attached to the end of the tubing 50 and distribute ozone more effectively to wet areas. It would also be possible to achieve favorable remediation by using a combination of air pumps and ozone generators 40 , which combination would still come within the scope of the present invention. In the opinion of this inventor, installation of the improved device of the present invention is relatively simple and straightforward and can frequently be accomplished by the homeowner. The user should first identify the components of his or her particular septic system. Frequently, the local government or health department will have information about the homeowner's septic system on file. However, as a general rule, home septic systems are comprised of a pipe running from the house to the septic tank, in some cases, a pipe running to a second septic tank or pumping chamber, and a typical distribution box that splits the effluent into several pipes going into the absorption field, as discussed above. With this configuration, there are several different locations in which the improved apparatus of the present invention can be installed to eliminate excess bio-mat. The preferred location to install the remediation equipment is as close to the bio-mat problem as possible. Therefore, in a septic system having a first septic tank 14 , a second septic tank or pumping chamber 18 , a dry well 22 and a distribution box 28 leading to one or more absorption field vents 3D, 34 , the preferred location would be in the dry well or seepage pit 22 . A secondary, but still beneficial location would be to install the aerator stone 60 in the distribution box 28 . However, it would also be beneficial to install the aerator stone 60 of the present invention after the second septic tank 18 . Obviously, different septic systems will require slightly different installations. In the event that a septic system 10 does not have a vent at a convenient location to monitor the progress of the remediation method, a monitoring well can be added to a conventional soil absorption system by driving a “sandpoint” well point not less than 12 inches and not more than 24 inches below the bottom of the soil absorption vent pipe 30 . The bottom of the “sandpoint” should be driven to the bottom of the soil absorption field 26 . Therefore, the effluent level in the “sandpoint” can then be monitored. The improved remediation apparatus of the present invention should be allowed to operate for six months. If the system 10 is severely plugged, the equipment can operate for more time without damaging the septic system. The depth of the ponded effluent should be recorded regularly. Frequently, plotting the data on a program such as Microsoft® Excel will enable the user to predict the amount of time required for remediation. A good estimate of the required operating time can be obtained by examining a plot of the Ponded Effluent Depth as shown in FIG. 5 . Normally, treatment should continue for two months after the ponded effluent depth stabilizes. For the system plotted in FIG. 5 , the owner of the septic system might expect to operate the system a total of 120 days. The user should expect some anomalous measurements during the remediation period. For example, in FIG. 5 , the ponded effluent depth in the septic system declined for several days, remained steady, and then rose again. This rise could be attributed to many things such as increased water usage and precipitation. This improved process and apparatus can also be applied to the effluent contained in a holding tank. In this application, the effluent category can be changed from untreated waste to treated waste. This re-categorization may reduce the pumping cost associated with the holding tank. Typically, untreated waste of a holding tank must be disposed of in a waste treatment facility. The waste treatment facility charges the waste hauler for this service, who in turn charges the owner of the holding tank. Treated waste can be alternatively distributed into the surface of the ground at less cost. Yet another application of this improved process and equipment is in mobile and portable holding tanks. Mobile and portable holding tanks can be found in but not limited to recreational vehicles, camping trailers, boats, etc. These holding tanks are anaerobic in nature and emit odorous methane gases. Owners typically add chemical odor controllers containing paraformaldehyde, alkyl dimethyl benzyl ammonium chloride (quaternary ammonium) or other disinfectants. These chemicals are toxic and detrimental to a private on-site wastewater treatment system. Many rural campgrounds are serviced by private on-site wastewater treatment systems. Many campgrounds discourage or have banned the use of these additives. As alluded to earlier, the application of ozone to any medium does not add any other chemicals. In this application, the naturally occurring aerobic bacteria can eliminate the odors of a blackwater or sewage holding tank. In fact, ozone in its gaseous state is a proven deodorizer for a variety of odorous materials. Ozone also has the proven ability to convert bio-refractory organic materials to biodegradable materials. Thus, ozone oxidation can produce wastewater with lower concentrations of problematic organic compounds. The equipment will keep the holding tank significantly free of sludge build up on the sidewalls and depth sensors. Application of this improved process to the gray water holding tank will also reduce odor and sludge build up on the sidewalls and depth sensors of the holding tank. This treated gray water is then suitable for the use of flushing the toilet. An embodiment of the above application is shown in FIGS. 6 and 7 , and provides a portable tank wastewater treatment system that may be used in mobile and portable holding tanks. Such holding tanks may be found in but not limited to recreational vehicles 102 , camping trailers, boats, portable restrooms, and non-vehicle portable restrooms. FIG. 6 schematically represents a portable tank wastewater treatment system 100 , with which the improved apparatus and method of the present invention is intended to be used. It is to be understood, however, that the precise configuration of the improved system is not a limitation of the present invention and could assume any number of sizes and layouts. The portable tank wastewater treatment system 100 shown is for illustration purposes only. The portable tank wastewater treatment system 100 includes a potable water source 105 , which may be treated with an ozone generating device 106 before it is sent to a point of use 110 . The point of use 110 may be a sink, shower, laundry machine, toilet, etc. After the water is expelled from the point of use 110 it enters a grey water holding tank 115 . While in the grey water holding tank 115 , the water is treated with a diatomic oxygen, ozone, or a combination of the two, by a generating device 116 , and is separated into solids, grey water, and clear water. The clear water is released from the grey water holding tank 115 and sent to a non-potable water holding tank 125 , while the solids and grey water are dumped to a wastewater treatment system 170 which may be a holding tank, wastewater facility, etc. The transfer of clear water to the non-potable water holding tank 125 may be aided by an optional pump 120 . An optional filter 127 may be installed before or after the pump. The water that is sent to the non-potable water holding tank 125 is again treated with a diatomic oxygen and ozone, or ozone only, generating device 126 before it is used to flush a toilet 135 . The water may be pumped via an optional pump 130 to the toilet 135 . An optional filter 131 may be installed before or after the pump. The non-potable water holding tank 125 may additionally dump a portion of the treated water to a grade/daylight site 155 , aided by an optional pump 150 , or to the wastewater treatment system 170 , aided by an optional pump 160 . The non-potable water holding tank 125 may additionally provide water to the potable water tank 105 via an intermediate holding tank 136 . This can be facilitated using optional pumps 137 and filters 138 . In addition, to improve the quality of the water, it is preferred to treat the water in the intermediate holding tank with oxygen, ozone, or a combination of the two. The toilet waste is expelled from the toilet 135 to a black water holding tank 145 where the water is again treated with a diatomic oxygen and ozone, or ozone only, generating device 146 . While in the black water holding tank 145 , the water is separated into clear water, black water, and solid waste. The clear water is returned to the non-potable water holding tank 125 , while the black water and solid waste is dumped to the wastewater treatment system 170 . Transfer to the non-potable water holding tank 125 may be aided by an optional pump 140 , and filtered by an optional filter 141 . Dumping to the wastewater treatment system 170 may be aided by an optional pump 165 . As illustrated with respect to the first embodiment, the ozone generating device 106 may include an air stone similar to the air stone 60 and a pump similar to pump 40 . In addition, the several diatomic oxygen and ozone, or ozone only, generating devices 116 , 126 , and 146 may also include such an air stone and pump. Also similar to the first embodiment, the air stones may be connected to the pumps with clear vinyl tubing similar to the tubing 50 . Based on the foregoing, it will be apparent that there has been provided an improved apparatus and method for introducing oxygen and ozone, or ozone only, into a failed or failing soil absorption field for the purpose of converting the biochemical process from an anaerobic one to an aerobic one. The forced introduction of oxygen and ozone, or ozone only, into the system allows the aerobic bacteria to scour the bio-mat, thereby working to reduce the thickness of the bio-mat and permitting the system to revert back to an anaerobic passive system as originally designed. By using, the improved method and apparatus of the present invention, the biochemical process is altered by complete or localized conversion of the soil absorption component as above described. The improved apparatus of the present invention may seem quite simple in practice compared to existing aerobic systems. However, the goal of this improved approach to remediation is value based. The idea is to provide an inexpensive and effective alternative to replacing the absorption system of a septic system. This has been accomplished by the improved method and apparatus of the present invention. In addition, a second embodiment provides an improved apparatus and method for introducing oxygen, ozone, or a combination of the two, into a portable tank wastewater treatment system for the purpose of water recycling, as well as the reduction and prevention of the build up of odorous organic material within the system. The forced introduction of oxygen, ozone, or a combination of the two, into the system at several key points allows aerobic bacteria to better process the wastewater. In addition, ozone has proven deodorizing characteristics and reduces the amount of odorous organic compounds often found in portable wastewater tanks thus allowing a user to maintain an acceptable environment near the wastewater tank without the use of prohibited or discouraged chemicals. Thus, the invention provides, among other things, an improved portable tank wastewater treatment system method and apparatus. Various features and advantages of the invention are set forth in the following claims.

4y

FIELD OF THE INVENTION [0001] The invention relates to the field of tumour diagnosis, in particular to predict the existence of metastases of a tumour, more in particular to the detection of lymph node metastases of head and neck squamous cell carcinoma (HNSCC) especially those that arise in the oral cavity and oropharynx. STATE OF THE PRIOR ART [0002] Head and neck squamous cell carcinoma (HNSCC) consists of a heterogenous group of neoplasms that arise from the epithelium of the upper aero-digestive tract. HNSCC is the fifth most common malignancy in humans and is particularly frequent in regions where alcohol and tobacco use is high (Sankanarayanan, R. et al., (1998) Anticancer Res. 18, 4779-4786). The survival rate of patients with cervical lymph node metastases is reduced by almost 50% (Jones, A. S. et al., (1994) Clin. Otolaryngol. 19, 63-69; Hahn, S. S. et al., (1987) J. Radiat. Oncol. Biol. Phys. 13, 1143-1147). As with most forms of cancer, treatment depends largely on progression stage (Forastiere, A. et al., (2001) N. Eng. J. Med. 345, 1890-1900). [0003] Metastasis is the process whereby cancers spread to distinct sites in the body. It is the principal cause of death in individuals suffering from cancer. For some tumor types, the earliest detectable sign of metastasis is the presence of malignant cells in lymph nodes close to the site of the primary tumour. Early detection of local lymph node metastases is currently pivotal for appropriate treatment of many types of cancer. However, because of difficulties in detecting lymph node metastases reliably, many patients currently receive inappropriate treatment. [0004] Most patients with HNSCC, especially those in the oral cavity or oropharynx have the primary tumour removed. Treatment of clinically diagnosed lymph node metastasis positive patients (N+) involves the additional surgical removal of a significant portion of the neck, including all five local lymph node levels: radical neck dissection (RND) (Robbins, K. T. et al., (2002) Arch. Otolaryngol. Head Neck Surg. 128, 751-758). However, after histological examination of the removed tissue, approximately 10-20% of the clinically diagnosed N+ patients appear to be N0 (metastasis free) (Woolgar, J. A., (1999) Br. J. Oral Maxillofac. Surg. 37, 205-209). Clinical diagnosis of N0 lymph node status is even less accurate. Histological examination of electively operated clinically diagnosed N0 patients reveals that about one-third have positive neck nodes (Jones, A. S. et al., (1993) Eur. Arch. Otorhinolaryngol. 250, 446-449). Different strategies exist for neck treatment of N0 diagnosed patients (Pillsbury, H. C., et al., (1997) Laryngoscope 107, 1294-1315). One is the so-called “watch and wait” strategy by which N0 diagnosed patients do not undergo any neck dissection. The involves the risk of fatality by allowing overlooked metastases to develop and spread further. Since the prevalence of false-negative predictions is very high, most clinics perform neck surgery for all diagnosed N0 patients. In this case most often a supra-omohyoidal neck dissection (SOHND) is performed, removing the three upper lymph node levels (Robbins, K. T. et al., supra). This treatment is less appropriate than an RND for those N+ patients falsely diagnosed as N0 and, moreover, completely unnecessary for all patients correctly diagnosed as N0. Although SOHND is less rigorous than RND, the treatment cause disfigurement, long-term discomfort, pain and can lead to additional complications such as shoulder disability (e.g. Short, S. O. et al., (1984) Am. J. Surg. 148, 478-482). Both treatments strategies result in over- or undertreatment due to limitations in detecting lymph node metastasis reliably. [0005] DNA microarray based gene expression profiling has previously been shown to be useful for cancer classification (e.g. Valk, P. J. et al., (2004) N. Eng. J. Med. 350, 1605-1616) and prognosis-based treatment (Van 't Veer, L. J. et al., (2002) Nature 415, 530-536 and WO 2004/065545). Gene expression profiling has revealed genes that are differentially regulated in metastases (Clark, E. A. et al., (2000) Nature 406, 532-535; Saha, S. et al., (2001) Science 294, 1343-1346) and a 17-gene expression signature was recently found that is common to both primary tumours and metastases (Ramaswamy, S. et al., (2003) Nat. Genet. 33, 49-54). It was also found that a signature derived from fibroblasts which are active in wound healing can be predictive for metastasis in several tumour types (Chang, H. Y., et al. (2004) PLoS Biol. 2(2):e7, to be found at: http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=314300). [0006] For HNSCC such expression signatures are starting to be uncovered (Chung, C. H. et al., (2004) Cancer Cell 5, 489-500), but as yet without independent validation for reliability and clinical outcome. [0007] Thus, there is still a large need for a reliable diagnostic tool on basis of expression of genes with which a reliable and accurate prediction can be established for the presence or occurrence of lymph node metastasis in HNSCC. SUMMARY OF THE INVENTION [0008] The invention now provides a nucleotide array of maximal 50 nucleotide sequences, preferably maximal 100 nucleotide sequences, more preferably maximal 1000 nucleotide sequences, for the detection of metastasis in head and neck squamous cell cancer (HNSCC) comprising at least 1 of the elements of Table 5, more preferably 2 of the elements, more preferably 3 of the elements, more preferably 4 of the elements, more preferably 5 of the elements, more preferably 6 of the elements %, more preferably 7 of the elements, more preferably 8 of the elements, more preferably 9 of the elements, more preferably 10 of the elements and most preferably at least 20 of the elements. Alternatively, a nucleotide array for the detection of metastasis in HNSCC has 50 or more of the elements of the genes listed in Table 4. [0009] Further provided is a method to establish reference and control gene expression profiles of patients having had metastasis after HNSCC(N+ group) or no metastasis after HNSCC(N0 group) by analysing the gene expression from a tumour biopsy sample of each patient, or from pooled samples of each group of patients, on an array according to the invention. [0010] Another embodiment of the invention is a method to predict the presence or risk of occurrence of lymph node metastasis of a HNSCC patient. comprising: [0011] a. taking a biopsy sample from the tumour of the patient; [0012] b. isolating the nucleic acid from the biopsy sample; [0013] c. analyse the gene expression profile of said nucleic acid by assaying it with a nucleotide array according to the invention; [0014] d. classifying the expression profile as N+ or N0 by determining whether the expression profile would match the expression profile of a group of HNSCC patients known to have developed metastasis. [0015] Preferably, the biopsy samples in the above methods are fresh biopsy samples. [0016] A preferred embodiment for the method to predict the presence or risk of metastasis is a method, wherein the analysis of the gene expression profile comprises: [0017] a. hybridising the nucleic acid form the biopsy sample with the nucleotide array according to the invention; [0018] b. determining the amount of hybridisation of each of the elements of the nucleotide array relative to the amount of hybridisation of each element with a reference sample, said step optionally involving a normalisation step; [0019] c. determining for each element of the array whether the expression of the corresponding gene in the biopsy sample is more or less than the expression of the corresponding gene in the reference sample. [0020] Preferably, the expression profile is classified as N+ (high risk of metastasis) or N0 (low or no risk of metastasis) according to the steps of: [0021] a. determining the collective correlation of the classifier/predictor genes or elements present in the expression profile with the average N+ or N0 profile from primary tumors with previously established N-status; and [0022] b. determining the predictive threshold based on the correlation threshold from primary tumors with previously established N-status [0023] In another preferred embodiment the method is a method, wherein the gene expression profile of a group of HNSCC patients known to have developed metastasis is the expression profile contained in the dataset E-UMCU-11, available in the public microarray database ArrayExpress (http://www.ebi.ac.uk/arrayexpress/). [0024] Calculation of the correlation as performed in the above methods is preferably done using the cosine correlation method. [0025] Normalization of the expression profile is preferably achieved by correcting the expression data for experimental variations with the help of expression data of a control gene or element which is not affected by the tumour state, preferably by calculating the ratio of the expression data of each gene or element in the array of claim 1 or 2 with the expression of a control gene or element or the mean of a pool of control genes or elements. LEGENDS TO THE FIGURES [0026] FIG. 1 . A predictor for HNSCC lymph node metastasis. (a) Expression profiles of the 102 predictor genes on the 82 primary tumor training set (middle). The predictor genes are clustered based on their similarities across the 82 tumors (Pearson around zero correlation, centroid clustering). Tumors are rank-ordered according to their correlation with the average N0 expression profile (left). The solid line represents the threshold for optimal overall accuracy. Tumors above the threshold show an expression profile that indicates that the patient is free of lymph node metastasis. In the right panel the patient's histological N-status, including the 3 year follow-up period, and the clinical diagnosis are shown (black indicates post-operative histological N+, white indicates post-operative histological N0, dark grey indicates clinical N+ and light grey indicates clinical N0 assessment). The asterix indicates a patient that developed lymph node metastasis post-treatment. (b) Expression profiles and tumor correlations from 6 training tumors samples (circles) and their technical replicates (squares). (c) as (a) only for a independent validation set of 22 primary HNSCC tumors. The threshold is set according to the optimal threshold established with the latter half of the training set ( FIG. 2 d ). [0027] FIG. 2 . Long-term tissue storage results in loss of predictive accuracy. (a) The mean correlation with the average no-metastasis profile and the standard deviation range for N0 patients (blue) and N+ patients (red) in the training set are shown for each year of surgery. (b) The N0 (blue), N+ (red) and overall (green) predictive accuracies increase from 40-45% for samples from 1996, to 89-100% for samples from 2000. (c, d) Correlation data from tumors with longer (c) or shorter (d) storage time. The predictor correctly predicts 22 of the 38 and 38 of the 44 samples, respectively. [0028] FIG. 3 . The predictor outperforms current clinical diagnosis on the validation set. (a) Predictive accuracies (PA) of current clinical diagnosis (blue) and the predictor (red) on the validation set. Error bars are based on the standard error for predictive accuracy. The predictor has a N0 PA of 100%, N+ PA of 77%, and overall PA of 86%. Clinical diagnosis has a N0 PA of 67%, N+ PA of 71%, and overall PA of 68%. (b, c) Treatment accuracy for the validation set, based on current clinical diagnosis (b) or if based on predictor outcome (c). Completely appropriate treatment is shown in green and under- or overtreatment in red. Current diagnosis resulted in 23% of patients receiving appropriate treatment (50% of N+ receiving an RND). Predictor based treatment would result in 86% of patients receiving appropriate treatment (75% of N0 that no longer receive any neck dissection and 100% of N+ receiving a RND). [0029] FIG. 4 . Study design and procedures overview. a, RNA was isolated from 2-3 tumor sections, followed by mRNA amplification and fluorescent labeling. After hybridization, scanned images were quantified and the data was normalized. Duplicates of each tumor were averaged and a predictor was designed using the differentially expressed genes. Quality control monitoring occurred after total RNA isolation, cRNA synthesis, labeling, scanning and normalization. b, The training experiment design involved 82 primary HNSCC tumors, compared in duplicate dye-swap against a common reference pool containing equal amounts of cRNA from each tumor. Nine reference pool self-self comparisons were generated in parallel, to establish an error-model for technical variation. c, The predictor was designed using a double loop training-validation protocol. [0030] FIG. 5 . The predictive outcome of different signatures is stable. Predictive correlation outcome of 66 tumor samples using a multiple training approach. A thousand different molecular signatures comprising 50 (A), 100 (B) or 200 (C) genes were used to predict each sample approximately 100 times. Samples from patients without metastasis are colored blue (top line in the graph), samples from patients with lymph node metastasis are colored red (bottom line in the graph). The shaded area represents the 95%-confidence interval for the sample predictions. DETAILED DESCRIPTION OF THE INVENTION [0031] The inventors herein show that it is possible to give a more accurate prediction of the presence of lymph node metastasis of HNSCC than currently possible, by measuring mRNA expression of a concise set of genes (the predictor signature). It appeared possible to give an accurate prediction on basis of a set of 102 genes listed in Table I. It appeared that half of these genes have not been directly associated with tumorigenesis or metastasis before. Besides expected epithelial marker genes, interesting categories include genes (putatively) coding for extracellular matrix components, genes involved in cell adhesion including three members of the plakin family of cytolinkers and the enzyme transglutaminase 3, which play a role in maintaining tissue integrity; cell death genes; cell growth and maintenance genes and genes encoding hydrolyzing activities including proteins involved in degradation of the extracellular matrix (uPA and PAI-1) and a metalloproteinase. Another feature of the metastasis signature is that there is more down-regulation associated with metastasis (two thirds) than up-regulation. It is likely that this involves stromal and immune-regulatory components (Pollard, J. W. (2004) Nat. Rev. Cancer 4, 71-78; Chambers, A. F. et al. (2002) Nat. Rev. Cancer 2, 563-572). Many of the predictor genes belong to this categories, strengthening the argument for profiling bulk tumour tissue rather than laser-dissected regions densely populated with tumour cells. [0032] It is shown herein that a diagnosis/prediction of the presence of metastases can be given using expression data of a set of only five genes from this large set of 102 genes. Table 2 indicates 15 of the genes which rank high in predictive value and which can especially be used to give a diagnosis or prediction of metastasis in HNSCC. Of course, accuracy of prediction will increase when more then five, preferably all 15 and even more preferably all 102 genes will be used on an array for gene expression analysis for the diagnostic/predictive signature. [0033] Gene expression analysis is preferably done using a micro-array. The techniques for measuring and comparing gene expression on micro-arrays is well established within the art. It should be understood that it is not necessary to have the full length nucleotides encoding the above mentioned genes on said array: a stretch of nucleotides which is sufficient to establish unique hybridisation with the RNA expressed from said genes in the tumour cells can be used. Such a stretch of nucleotides is hereinafter referred to as ‘element’. Preferably for the specific use of gene expression analysis for the current invention (i.e. with relation to detection of the presence of or the risk for metastases of HNSCC) such an array need not contain a large number of (different) genes or elements. It would be sufficient for the array to contain the necessary genes, as discussed above, and, preferably, some control genes, as will be discussed below. The array, which can be used for the analysis of the invention thus does not need to contain more than 1000 genes or elements, preferably not more than 500 genes or elements, more preferably not more than 200 genes or elements and most preferably from about 50 to about 150 genes or elements. [0034] To investigate a gene expression profile the array should be subjected to hybridisation with target polynucleotide molecules from a clinically relevant source, in this case e.g. a person with HNSCC. Therefore, preferably a fresh frozen (within 1 hour from surgical removal), liquid nitrogen (at least −80° C.) stored tumour sample needs to be available. Said target polynucleotide molecules should be expressed RNA or a nucleic acid derived therefrom (e.g., cDNA or amplified RNA derived from cDNA that incorporates an RNA polymerase promoter). If the target molecules consist of RNA, it may be total cellular RNA, poly(A) + messenger RNA (mRNA) or fraction thereof, cytoplasmic mRNA, or RNA transcribed from cDNA (cRNA). Methods for preparing total and poly(A) + messenger RNA are well known in the art, and are described e.g. in Sambrook et al., (1989) Molecular Cloning—A Laboratory Manual (2 nd Ed.) Vols. 1-3, Cold Spring Harbor, N.Y. In one embodiment, RNA is extracted from cells using guanidinium thiocyanate lysis followed by CsCl centrifugation (Chrigwin et al., (1979) Biochem. 18:5294-5299). In another embodiment, total RNA is extracted using a silica-gel based column, commercially available examples of which include RNeasy (Qiagen, Valencia, Calif., USA) and StrataPrep (Stratagene, La Jolla, Calif., USA). Poly(A) + messenger RNA can be selected, e.g. by selection with oligo-dT cellulose or, alternatively, by oligo-dT primed reverse transcription of total cellular RNA. In another embodiment, the polynucleotide molecules analyzed by the invention comprise cDNA, or PCR products of amplified RNA or cDNA. [0035] Preferably, the target polynucleotides are detectably labelled at one or more nucleotides. Any method known in the art may be used to detectably label the nucleotides. Preferably, this labelling incorporates the label uniformly along the length of the polynucleotide and is carried out at a high degree of efficiency. One embodiment for this labelling uses oligo-dT primed reverse transcription to incorporate the label; however, conventional methods hereof are biased toward generating 3′ end fragments. Thus, in this embodiment, random primers (e.g. 9-mers) are used in reverse transcription to uniformly incorporate labelled nucleotides over the full length of the target polynucleotides. Alternatively, random primers may be used in conjunction with PCR methods or T7 promoter-based in vitro transcription methods in order to amplify the target polynucleotides. [0036] In a preferred embodiment, the detectable label is a luminescent label. For example, fluorescent labels, bioluminescent labels, chemiluminescent labels and calorimetric labels may be used. In a highly preferred embodiment, the label is a fluorescent label, such as a Cy5 or Cy3, fluorescein, a phosphor, a rhodamine, or a polymethine dye or derivative. In another embodiment, the detectable label is a radiolabeled nucleotide. [0037] The array may be any nucleotide array which represents five or more of the genes of Table 2 or Table 1. To indicate the difference with the existing very large arrays of e.g. Affymetrix, the dedicated arrays of the present invention should preferably comprise no more than 50, or 100, or 250 or, alternatively 500 or 1000 genes altogether. Presence of other genes on the array is allowable and the expression data from such other genes need not necessarily be considered for the present application. The methods of the invention can be applied on the above mentioned dedicated arrays, but can also be performed on arrays that are commercially available (e.g. from Agilent US; Affymetrix Inc, CA, USA; and others). It is also possible to work with self-made arrays by spotting or synthesizing nucleotides which are known to selectively hybridise to the target genes on a surface. Methods to prepare such arrays are well within the skill of the artisan. The microarrays can comprise cDNA, but can also comprise short oligonucleotides (Affymetrix and Nimblegen) or long oligonucleotides which are synthesized in situ_(Agilent); in another embodiment the arrays comprise long oligonucleotides and are self-made by spotting. [0038] Nucleic acid hybridisation and wash conditions are chosen so that the target polynucleotide molecules specifically hybridize to the complementary polynucleotide sequences of the array, preferably to a specific array site, wherein its complementary DNA is located. Optimal hybridisation conditions will depend on the type (e.g., RNA or DNA) of the target nucleotides and array. General parameters for specific (i.e., stringent) conditions of hybridisation are described in Sambrook et al. (supra). Typical hybridisation conditions for cDNA microarrays are hybridisation in 5×SSC plus 0.2% SDS at 65° C. four hours, followed by washes at 25° C. in low stringency wash buffer (1×SSC plus 0.2% SDS), followed by 10 minutes at 25° C. in higher stringency wash buffer (0.1×SSC plus 0.2% SDS). [0039] When fluorescently labelled probes are used, the fluorescence emissions at each site of the microarray may be detected by scanning confocal laser microscopy. In one embodiment, the arrays is scanned with a laser fluorescent scanner with a computer controlled X-Y stage and a microscope objective. Fluorescent laser scanning devices are described in e.g. Schena et al. (1996) Genome Res. 6:639-645. Signals are recorded and, in a preferred embodiment, analysed by computer using a 12 or 16 bit analog to digital board. In one embodiment the scanned image is despeckled using a graphics program (e.g., Hijaak Graphics Suite) and then analysed using an image gridding program that creates a spreadsheet of the average hybridisation at each wavelength at each site. [0040] Not all of the genes are evenly contributing to the discriminating effect. As is shown in Table 1, the genes differ in significant expression. Although the statistical data presented in the Examples are calculated with all of the 102 genetic elements of Table 1, it is submitted that a good distinction between the two groups of patients and therewith a good diagnosing/predicting ability of the signature gene set can also be achieved with only a part of the elements of Table 1. At least 5 (5%) of the elements of Table 1 are included in the analysis, more preferably 20%, more preferably 40%, more preferably 60%, more preferably 80%, more preferably 90% and most preferably all of the elements. It would be advisable not to randomly choose the elements, but to pick the most discriminating genes in this list. Table 2 gives an overview of the top 15 genes out of the 102 genes of table 1, of which at least 5, more preferably at least 6, more preferably at least 7, more preferably at least 8, more preferably at least 9, more preferably at least 10, more preferably at least 11, more preferably at least 12, more preferably at least 13, more preferably at least 14, and most preferably all 15 can be used for making up the signature with which the microarray analysis is performed. [0041] It furthermore has been found that a more comprehensive set of predicting genes can be compiled by repeatedly calculating a predictive signature via a multiple training approach (similar to Michiels, S. et al., Lancet 365:488-492, 2005). In this study (see Examples) it appeared that from the originally more than 2000 differentially expressed genes only 825 (Table 3) had a predictive character, and that for these a subgroup of 179 (Table 4) genes was used in more than half of the signatures. From this group again a supergroup of 61 genes (Table 5) could be distinguished which was predominantly used to discriminate between N+ and N0. It will be understood that preferably an array would comprise at least three, but preferably five, more preferably 10, even more preferably 25 and most preferably 61 of the genes of Table 65. However, it also appeared possible to classify on basis of genes, which did not occur in Table 5, but in such cases many genes are required to achieve an acceptable prediction. Thus, an array could also comprise at least 10, preferably 25, more preferably 50, and most preferably 100 of the genes of Table 5. [0042] As indicated above, various combinations of these genes can be used for determining the presence of lymph node metastases in several ways. [0043] On dual channel DNA microarrays this is performed by determining the expression level ratios of the genes in the primary tumour sample versus expression of the same genes in reference material. The reference material can be derived from a pool of total RNA or amplified mRNA from a set of HNSCC primary tumours with established lymph node metastasis characteristics. The individual gene expression ratios contribute towards the expression ratio signature of a sample. The degree of correlation of a sample's signature with the signatures of samples with known metastatic status (preferably calculated by the cosine correlation (Jones, W. P., & Furnas, G. W. (1987). Pictures of Relevance: A Geometric Analysis of Similarity Measures. Journal of the American Society for Information Science, 36 (6), 420-442) as, e.g, provided by the Genesis software; http://genome.tugraz.at/Software/Genesis/Description.html) is used to predict the metastatic state of the unknown sample. The correlation threshold for predicting the metastatic state is based on the optimal threshold for discriminating between the metastatic states of the samples with known metastatic states, which can easily be determined by a person skilled in the art [0044] Other measurements of absolute expression and expression ratios of these genes can also be used. Reference material can be derived from other sources than a pool of samples with known metastatic states. Preferably, however, samples with known metastatic states are still required to determine the correlation threshold for determining the metastatic status. [0045] Expression ratios can also be derived from single channel microarray experiments, using as a reference so-called housekeeping genes (i.e. with stable expression across many different samples) or a collection of housekeeping genes or any collection of genes or features with stable expression. Again here it is preferred to use samples with known metastatic states to determine the correlation threshold for determining the metastatic status. [0046] Gene expression measurements and the derived ratios can also be obtained by (quantitative) reverse transcription PCR or any other assay for gene expression, using as a reference any gene or collection of genes that have stable expression across many samples. In a specific embodiment of this application of the invention, samples with known metastatic states are still required to determine the correlation threshold for determining the metastatic status. [0047] In the absence of tumour samples with known metastatic states for calibration of the prediction, the genes or various combinations of the (expression analysis of the) genes can still be used to predict the metastatic state. In these embodiments of the invention an absolute or relative measurement of gene expression is determined for example using single or dual channel DNA microarrays, or by other methods such as (quantitative) reverse transcription PCR. Increased expression of the genes in table 1 or 2 with a positive N+ correlation will hereby contribute positively towards prediction of the N+ status and negatively towards prediction of the N0 status. Conversely, increased expression of the genes in table 1 or 2 with a negative N+ correlation will contribute positively towards N0 prediction and negatively towards N+ prediction. Increased expression in both cases indicates an increase relative to a suitable marker gene or feature, set of genes or features or collectively in relation to each other. [0048] However, a person skilled in the art is able to obtain the reference data that have been produced in the below example, since this data is available as dataset E-UMCU-11 from the public micro-array database ArrayEcpress (http://www.ebi.ac.uk/arrayexpress/). When desiring to predict or determine the presence of metastases for a certain patient, the practitioner should take a biopsy from that patient, isolate the RNA and determine the expression of at least 5 of the elements of Table 1. To normalize these expression data with respect to the data of the reference set E-UMCU-11, it is possible to correct the data for variations with the help of expression data of a control gene or element which is not affected by the tumour state (such as a housekeeping gene), which is present in the reference set E-UMCU-11 and should also be available on the array that has been used to determine the expression profile of the patient to be assessed. In stead of one control gene or element, also the mean value of a poll of control genes or elements can be taken. This correction can, for instance, be done by subtracting the expression level of the control gene(s)/element(s) from the expression levels of each of the tested genes/elements. Preferably, the ratio for every tested gened with respect to the control gene(s) is calculated for both the patient's expression profile as well as for the expression data of the reference set. [0049] With these figures, the correlation with the mean value of the N0 values of the reference set should be calculated. If this correlation is negative (i.e. a value below zero) it can be concluded that the patient is N+ (i.e. having or prone to develop metastases). Conversely, the correlation can be calculated with respect to the mean value of the N+ values of the reference set. Then a negative correlation indicates a match with the N0 group. [0050] Further enablement for a diagnosis/prediction of cancer metastasis on basis of gene expression analyses can be found in WO 03/010337, indicating that methods as have been generally described above are well within the skills of the practitioners in the art. EXAMPLE Data Accessibility [0051] MIAME 1 compliant data in MAGE-ML 2 format as well as complete descriptions of protocols, microarrays and clinical parameters have been submitted to the public microarray database ArrayExpress (http://www.ebi.ac.uk/arrayexpress/) with the following accession numbers: Microarray layout, A-UMCU-3; HNSCC tumour data, E-UMCU-11; Protocols for sectioning of tumour material, P-UMCU-18; RNA isolation, P-UMCU-19; DNase treatment, P-UMCU-20; mRNA amplification, P-UMCU-21; generating reference pool, P-UMCU-26; cRNA labeling, P-UMCU-22; hybridization and washing of slides, P-UMCU-23 and P-UMCU-24; scanning of slides, P-UMCU-25; Image analysis, P-UMCU-11 Tumor Samples [0052] For the training set, 92 samples were randomly taken from a collection of primary tumours surgically removed between 1996 and 2000 and that fulfilled the following criteria: biopsy-proven HNSCC in the oropharynx and oral cavity; no previous malignancies in the head and neck region; tumour sections contained more than 50% tumour cells. Of these 92 tumours, 82 passed total RNA and cRNA quality control (QC) and were included in this study. For the validation set, 27 tumours were randomly taken from the same collection of tumours, surgically removed between 2000 and March 2001, and that fulfilled the same selection criteria. Of these, 22 passed total RNA and cRNA QC and were included in this study. The diagnostic procedures for clinical staging of cervical lymph nodes was performed according to the Netherlands national guidelines for oral cavity and oropharynx carcinomas, by clinical examination (palpation) of the neck region, followed by bilateral ultrasound examination, computed tomography (CT) and/or magnetic resonance imaging (MRI). Suspected nodes were subjected to aspiration cytology. In this way, patients were pre-operatively classified as either N0 or N+, the latter in the case of aspirates yielding metastatic tumour cells. Only in the case of obvious neck involvement, as shown by huge swelling, were the patients classified as N+ without additional efforts to prove the presence of metastasis. [0053] Surgery was aimed at complete tumour removal. With regard to the neck, in the case of clinical N0 only a SOHND was performed 3 . In cases clinically classified as N+ a RND was performed including all five lymph node levels 3 . Postoperative irradiation was administered in accordance with current practice and depending on margin status, tumour growth features, number of positive nodes and extracapsular growth. In practice, 36 out of 60 clinically assessed N0 patients and 38 out of 43 clinically assessed N+ patients received radiation therapy. This treatment as well as additional clinical information is presented in Supplemental data 2 (for accessibility, see above). After surgery, patients were periodically checked for development of neck metastasis, and patients initially classified as N0 but showing positive nodes in their surgical specimen or developing neck nodes within a time span of 3 years after surgery without having another head and neck cancer that could be responsible for this metastasis, were retrospectively added to the N+ patient group. Less than 5% of patients with HNSCC in the oral cavity or oropharynx subsequently develop metastasis after treatment 4,5 . Here, for the training and validation cohorts, one patient subsequently developed positive neck nodes after surgery. Three years is to be considered as a reliable time period, since at least 80% of the recurrences are known to take place in the first two years after surgery (Takes, R. P. et al. (2001) J Pathol 194, 298-302; Jones, K. R., et al., (1992) Arch. Otolaryngol. Head Neck Surg. 118, 483-485) [0054] Fresh tumour tissue was taken from the surgical specimen, snap-frozen in liquid nitrogen immediately after surgical removal and stored at −80° C. Frozen sections were cut for RNA isolation and immediately transferred to a RNAlater solution (Ambion). A haematoxylin and eosin stained section was prepared for tumour percentage assessment. Only samples with at least 50 percent tumour cells were used. For a small number of samples the tumour percentage was increased by removing areas with no tumour cells. RNA Isolation [0055] Total RNA was isolated from 2-3 sections (20 μm) with TRIzol reagent (Invitrogen), followed by a purification using the RNeasy mini-kit (Qiagen) and a DNase treatment using the Qiagen DNA-free kit. The yield and quality of total RNA was checked by spectrophotometry and by the Agilent 2100 Bioanalyser (Agilent). Total RNA quality control criteria were in accordance with the Tumour Analysis Best Practices Working Group 6 , discarding samples with no clear 18S and 28S ribosomal bands. We also removed samples that had a yield lower than 500 ng total RNA or showed mycoplasma contamination. [0000] cRNA Synthesis and Labeling [0056] mRNA was amplified by in vitro transcription using T7 RNA polymerase on 1 μg of total RNA. First a double stranded cDNA template was generated including the T7 promoter. Next, this template was used for in vitro transcription with the T7 megascript kit (Ambion) to generate CRNA. During the in vitro transcription, 5-(3-aminoallyl)-UTP (Ambion) was incorporated into the single-stranded cRNA. The yield and quality of the cRNA was analyzed by spectrophotometry and by the Agilent 2100 Bioanalyser. Samples with a yield less than 5000 ng or with small cRNA fragments (median less than 500 bp) were not used. [0057] Cy3 or cy5 fluorophores (Amersham) were coupled to 500 ng of cRNA. After coupling, free dye molecules were removed using Clontech ChromoSpin-30 columns (Clontech). The yield and label incorporation (5-7%) of the cy-labeled cRNA was checked using spectrophotometry. Before hybridization, 300 ng of cy-labeled cRNA from one tumor was mixed with an equal amount of reverse color cy-labeled material from the reference sample. Microarray Production [0058] The Human Array-Ready Oligo set (version 2.0) was purchased from Qiagen and printed on Corning UltraGAPS slides as described elsewhere 7 . The microarrays contained 70-mer oligonucleotides representing 21,329 genes as well as 3871 additional features for control purposes. Microarray Hybridization [0059] Before use, the microarray slides were treated with sodium-borohydrate solution to reduce auto-fluorescence in the cy3-channel 8 . The labelled cRNA targets were hybridized on the microarray for 10 hours at 42° C. using the Ventana Discovery Hybridization Station in combination with the ChipMap-80 Kit (Ventana Europe). After hybridization the slides were manually washed and scanned in the Agilent G2565AA DNA Microarray Scanner (100% laser power, 30% PMT). Pre-Processing of Expression Data [0060] The scanned images were quantified and background corrected using Imagene 4.0 software (Biodiscovery). The expression data was normalized for dye and print-tip biases using a Lowess per print-tip normalization algorithms applied in the statistical package R 10 . Following normalization, variance stabilization (VSN) 11 was applied to stabilize variance in the intensity data. Both duplicate dye-swap hybridizations of each tumour were averaged and for each gene a tumour-reference ratio was calculated. Reference versus reference hybridizations were used to build a gene error model for technical variation. Nine reference self-self comparisons were performed in dye-swap (18 hybridizations), resulting in nine reference ratios for each gene on the microarray. These nine reference ratios yield an estimate of the technical variation for each gene. To test whether a gene in a tumour samples shows differential expression, a Student's t-test was applied on the tumour ratio and the corresponding nine reference ratios (technical variation). The calculated p-values for differential expression were used to select those genes that show differential expression in the tumour samples. Supervised Classification [0061] A classifier was constructed to distinguish between N0 and N+ patients. Of the 21,329 genes on the microarray, 6221 were excluded based on aberrant signal and spot morphology in one of the 164 hybridizations. From these remaining 15,108 genes, only genes that were significantly different from the reference in at least 31 tumours were selected based on the error model for technical variation (p<0.01). This resulted in a set of 1,986 genes. For these genes the signal-to-noise-ratio (SNR) 12 was computed and employed to rank the genes (top ranked genes being genes that are best suited to distinguish the outcome classes). The optimal gene set to employ in the classifier (a nearest mean classifier similar to the classifier employed in 13 ), was determined by gradually expanding the gene set starting from the highest ranked gene. At each expansion round the nearest mean classifiers was trained on a training set and tested on a test set. The performance on the test set served as a quality measure of the gene set. The performance was measured as the average of the false positive (N0 classified as N+) and false negative (N+ classified as N0) rates of the test samples. Initially the performance increases as the set is expanded. The expansion of the gene set is terminated when the performance deteriorates, i.e. when the optimal performance is reached. The steps of ranking the genes and training and testing the classifier are performed in a 10-fold cross-validation procedure. The output of this procedure is an optimal number of top-ranked genes and a trained classifier. To ensure independent validation, this process of optimizing the set of genes and training the classifier is wrapped in a second 3-fold cross-validation loop. This entails that the optimization of the gene set and the training of the classifier is performed on ⅔ of the data, while the classifier is validated on ⅓ of the data. Since this ⅓ of the data is never involved in any of the gene selection and training steps, this ensures completely independent validation of the classifier, which avoids selection bias 14,15 and therefore results in a reliable performance estimate. This double-loop procedure determined 102 genes to form the final diagnostic classifier. This classifier was trained on the complete set of 82 samples by recalculating the signal-to-noise ratio for all genes and subsequently selecting the top 102 genes. The predictor was trained using the 102 selected genes and the 82 training samples. A decision threshold for this classifier was fixed such that the highest overall predictive accuracy for both N0 and N+ tumours. was reached. Statistics [0062] Odds ratios (OR) were calculated by fitting a logistic regression model on the prediction outcome of the validation set. The predictor had an infinitive OR since no false negative prediction was made. To get an estimate of the OR for the predictor, one false negative was artificially introduced resulting in a predictor OR of 30 (p=0.006) and a clinical OR of 4.2 (p=0.15). The standard error for predictive accuracy ( FIG. 3 a ) includes the predictions made on the latter half of the training set. Selection of Predictive Genes [0063] A multiple training approach was used to identify a complete set of predictive genes, based on the 66 tumor samples from 1998 to 2001. The tumor samples were randomly divided into a training set and test set using a 10-fold cross validation procedure. Based on the training set, P-values were calculated for all 3064 differentially expressed genes based on the difference in expression between N+ and N0 tumor samples (Student's T-test). The set of genes with lowest P-values (i.e. most-predictive) was used for prediction of the test samples by calculating the correlation with the average N+ and average N0 training profile and, based on these correlations, classifying the test samples as N0 or N+. Repeating this resampling procedure a thousand times resulted in multiple predictions for each tumor sample, based on the different predictive gene sets. This approach was repeated three times to determine 1000 predictive gene sets consisting of 50 genes, 1000 gene sets of 100 genes and 1000 gene sets of 200 genes. All gene sets had predictive value ( FIG. 1 ). Genes selected at least once are listed in Table 3. This consists of 825 genes with predictive power for detection or prediction of metastasis in head and neck squamous cell carcinoma. Small and large sets of genes from this list can be used for prediction ( FIG. 5 ). Genes selected more frequently, that is present in more than 50% of the 200 gene set predictors are listed in Table 4. This consists of 179 genes with strongest predictive power for detection or prediction of metastasis in head and neck squamous cell carcinoma. Small and large sets of genes from this list can be used for prediction. Genes selected most frequently (more than 90%) are listed in Table 5. This consists of 51 genes with the highest predictive power. Small and large sets of genes from this list can be used for prediction. This list consists of genes, most/all of which have never before been associated with prediction of metastasis in tumors, especially metastasis in head-neck squamous cell carcinoma. REFERENCES [0000] 1. Brazma, A. et al. Minimum information about a microarray experiment (MIAME)-toward standards for microarray data. Nat. Genet. 29, 365-371 (2001). 2. Spellman, P. T. et al. Design and implementation of microarray gene expression markup language (MAGE-ML). Genome Biol. 3, RESEARCH0046 (2002). 3. Robbins, K. T. et al. Neck dissection classification update: revisions proposed by the American Head and Neck Society and the American Academy of Otolaryngology-Head and Neck Surgery. Arch. Otolaryngol. Head Neck Surg. 128, 751-758 (2002). 4. Carvalho, A. L., Kowalski, L. P., Borges, J. A., Aguiar, S., Jr. & Magrin, J. Ipsilateral neck cancer recurrences after elective supraomohyoid neck dissection. Arch. Otolaryngol. 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[0000] TABLE 1 Complete list of the 102 HNSCC predictor genes Gene GenBank ID Gene name N+ corr FTH1 NM_002032 ferritin, heavy polypeptide 0.726 1 COL5A1 NM_000093 COL5A1 protein (collagen 0.627 5 type A1 like) NCOR2 NM_006312 Nuclear receptor co- 0.617 repressor 2 P4HA1 NM_000917 proline 4-hydroxylase 0.572 alpha polypeptide I TNFAIP3 NM_006290 tumour necrosis factor, 0.536 alpha-induced protein 3 PLAU NM_002658 urokinase plasminogen 0.535 activator (uPA) COL5A3 NM_015719 Collagen, type V, alpha 3 0.521 SPOCK NM_004598 Sparc/osteonectin, cwcv 0.500 and kazal-like domains proteoglycan (testican) FAP NM_004460 fibroblast activation 0.498 protein, alpha ADAM12 NM_003474 a disintegrin and 0.482 metalloproteinase domain 12 (meltrin alpha) TPM2 NM_003289 tropomyosin 2 (beta) 0.470 MICAL2 NM_014632 flavoprotein 0.459 oxidoreductase MICAL2 D2S448 XM_056455 D2S448 (Melanoma 0.446 associated gene) PAI-1 NM_000602 plasminogen activator 0.440 inhibitor type 1 REN NM_000537 renin 0.383 POSTN NM_006475 periostin, osteoblast 0.367 specific factor CKTSF1B1 NM_013372 cysteine knot superfamily 0.330 1, BMP antagonist 1 (DRM/GREMLIN) IER3 NM_003897 immediate early response 0.303 3 MMD NM_012329 monocyte to macrophage 0.300 differentiation-associated CTDSP1 NM_021198 CTD (carboxy-terminal 0.260 domain, RNA polymerase II, polypeptide A) small phosphatase 1 PSMD2 NM_002808 proteasome (prosome, 0.256 macropain) 26S subunit, non-ATPase, 2 MAN1B1 NM_016219 mannosidase, alpha, class 0.254 1B, member 1 DKK3 NM_013253 dickkopf homolog 3 0.140 ( Xenopus laevis ) NT5C3 NM_016489 5′-nucleotidase, cytosolic 0.138 III DAPK3 NM_001348 death-associated protein 0.022 kinase 3 NDUFB4 NM_004547 NADH dehydrogenase 0.012 (ubiquinone) 1 beta subcomplex, 4, 15 kDa UBA52 NM_003333 ubiquitin A-52 residue −0.002 ribosomal protein fusion product 1 C9orf5 NM_032012 chromosome 9 open −0.075 reading frame 5 COPG NM_016128 Coat protein gamma-cop −0.081 RGS5 NM_003617 regulator of G-protein −0.097 signalling 5 FLJ12236 AK022298 Homo sapiens cDNA −0.104 FLJ12236 fis, clone MAMMA1001244 IDI1 NM_004508 Isopentenyl-diphosphate −0.126 delta isomerase RPL37A NM_000998 ribosomal protein L37a −0.162 ZDHHC18 NM_032283 Zinc finger DHHC domain −0.175 containing protein 18 MO30 M26463 Homo sapiens −0.194 immunoglobulin mu chain antibody MO30 (IgM) mRNA, complete cds FLJ20073 NM_017654 Hypothetical protein −0.215 FLJ20073 FLJ30814 AK055376 Homo sapiens cDNA −0.222 FLJ30814 fis, clone FEBRA2001529 PLK2 NM_006622 polo-like kinase 2 −0.230 MMPL1 NM_004142 Matrix metalloproteinase- −0.230 like 1 Z95126 Human DNA sequence −0.232 from clone RP1-30P20 on chromosome Xq21.1-21.3 BAL NM_031458 B aggressive lymphoma −0.234 protein (BAL) OSBP2 NM_030758 Oxysterol binding protein −0.244 2 PARVB NM_013327 Parvin, beta −0.286 CEBPA NM_004364 CCAAT/enhancer binding −0.290 protein (C/EBP), alpha ZNF533 NM_152520 zinc finger protein 533 −0.291 ABCA12 NM_015657 ATP-binding cassette, sub- −0.293 family A (ABC1), member 12 LOR NM_000427 loricrin −0.322 E2F5 NM_001951 E2F transcription factor 5, −0.356 p130-binding APM2 NM_006829 Adipose specific 2 −0.360 CAPNS2 NM_032330 CAPNS2 (calpain small −0.360 subunit 2) MGC13219 NM_032931 Hypothetical protein −0.367 MGC13219 FLJ22202 NM_024883 Hypothetical protein −0.383 FLJ22202 KRT23 NM_173213 keratin 23 (histone −0.409 deacetylase inducible) PPT2 NM_005155 palmitoyl-protein −0.417 thioesterase 2 PGBD5 NM_024554 piggyBac transposable −0.469 element derived 5 SSH2 NM_033389 SSH2 (slingshot 2) −0.475 ALOX12B NM_001139 arachidonate 12- −0.480 lipoxygenase, 12R type MAL2 NM_052886 mal, T-cell differentiation −0.544 protein 2 ZD52F1 NM_033317 Hypothetical gene ZD52F1 −0.562 EPPK1 AB107036 Epiplakin 1 −0.566 S100A7 NM_002963 S100 calcium binding −0.580 protein A7 (psoriasin 1) FLJ22184 NM_025094 Hypothetical protein −0.586 FLJ22184 MAP17 NM_005764 membrane-associated −0.591 protein 17 (MAP17) FLJ13497 AK023559 Homo sapiens cDNA −0.603 FLJ13497 fis, clone PLACE14518 ECM1 NM_022664 extracellular matrix −0.610 protein 1 TGM3 NM_003245 transglutaminase 3 (E −0.629 polypeptide, protein- glutamine-gamma- glutamyltransferase) RAD17 NM_133344 RAD 17 homolog ( S. −0.631 pombe ) FLJ30988 AK055550 Homo sapiens cDNA −0.650 FLJ30988 fis, clone HLUNG1000030 C10orf26 NM_017787 chromosome 10 open −0.653 reading frame 26 PALM2 NM_053016 paralemmin 2 −0.655 C4.4A NM_014400 GPI-anchored metastasis- −0.665 associated protein homolog (C4.4A) ECG2 NM_032566 Esophagus cancer-related −0.670 gene-2 protein precursor (ECRG-2) PPL NM_002705 periplakin −0.672 HPCAL1 NM_002149 hippocalcin-like 1 −0.674 SLPI NM_003064 secretory leukocyte −0.677 protease inhibitor (antileukoproteinase) PI3 NM_002638 protease inhibitor 3, skin- −0.680 derived (SKALP) FLJ25911 AK098777 Hypothetical protein −0.680 FLJ25911 [Fragment] CLIC3 NM_004669 chloride intracellular −0.691 channel 3 BENE NM_005434 BENE protein −0.698 FLJ00074 AK024480 FLJ00074 protein −0.699 [Fragment] DKFZp547F AL512697 Homo sapiens mRNA; −0.706 134 cDNA DKFZp547F134 (from clone DKFZp547F134) PLA2G4B NM_005090 phospholipase A2, group −0.707 IVB (cytosolic) AF339799 Homo sapiens clone −0.708 IMAGE: 2363394, mRNA sequence TRGV9 BC062761 T cell receptor gamma −0.710 variable 9 DSG3 NM_001944 desmoglein 3 (pemphigus −0.711 vulgaris antigen) FLJ12787 NM_032175 Hypothetical protein −0.734 FLJ12787 LLGL2 NM_004524 lethal giant larvae −0.738 homolog 2 ( Drosophila ) SMC5L1 NM_015110 SMC5 structural −0.741 maintenance of chromosomes 5-like 1 ODCP NM_052998 Ornithine decarboxylase- −0.741 like protein (EC 4.1.1.17) (ODC-paralogue) (ODC-p) FLJ31161 AK055723 Homo sapiens cDNA −0.747 FLJ31161 fis, clone KIDNE1000028 FLJ21214 AK024867 Homo sapiens cDNA: −0.748 FLJ21214 fis, clone COL00523 SPINK5 NM_006846 serine protease inhibitor, −0.749 Kazal type, 5 KIAA0350 XM_290667 KIAA0350 protein −0.760 PGLYRPL NM_052890 peptidoglycan recognition −0.764 protein L precursor S100A9 NM_002965 S100 calcium binding −0.773 protein A9 (calgranulin B) DNAH11 NM_003777 Dynein, axonemal, heavy −0.776 chain-11 LAGY NM_032495 lung cancer-associated Y −0.793 protein; homeodomain- only protein IVL NM_005547 involucrin −0.801 TNFRSF5 NM_001250 tumor necrosis factor −0.802 receptor superfamily, member 5 (CD40) SRP19 NM_003135 signal recognition particle −0.814 19 kDa KLK12 NM_019598 kallikrein 12 −0.837 IL22RA1 NM_021258 interleukin 22 receptor, −0.885 alpha 1 [0000] TABLE 2 Gene GenBank ID Gene name N+ corr. COL5A3 NM_015719 Collagen, type V, alpha 3 0.520719 COL5A1 NM_000093 COL5A1 protein (collagen 5 0.626949 type A1 like) ZD52F1 NM_033317 Hypothetical gene ZD52F1 −0.56185 FLJ25911 AK098777 Hypothetical protein FLJ25911 −0.6799 [Fragment] EPPK1 AB107036 Epiplakin 1 −6.56641 KIAA0350 XM_290667 KIAA0350 protein −0.76021 DNAH11 NM_003777 Dynein, axonemal, heavy −0.77599 chain-11 PI3 NM_002638 protease inhibitor 3, skin- −0.67983 derived (SKALP) P4HA1 NM_000917 procollagen-proline, 0.572479 2-oxoglutarate 4-dioxygenase (proline 4-hydroxylase), alpha polypeptide I ODCP NM_052998 Ornithine decarboxylase-like −0.74146 protein (EC 4.1.1.17) (ODC- paralogue) (ODC-p) MMD NM_012329 monocyte to macrophage 0.299881 differentiation-associated TPM2 NM_003289 tropomyosin 2 (beta) 0.470038 SRP19 NM_003135 signal recognition particle −0.81361 19 kDa IL22RA1 NM_021258 interleukin 22 receptor, −0.88482 alpha 1 FLJ31161 AK055723 Homo sapiens cDNA FLJ31161 −0.7475 fis, clone KIDNE1000028 [0000] TABLE 3 List of 825 genes with predictive value N+ UniProt Gene_symbol GB_accession UniGene_ID correlation Gene Q9NZQ6 COL5A3 NM_015719 235368 0.57481098 Collagen, type V, alpha 3 FINC_HUMAN FN1 NM_002026 287820 0.55126846 Fibronectin 1 FSL1_HUMAN FSTL1 NM_007085 296267 0.53452734 Follistatin-like 1 ER22_HUMAN KDELR2 NM_006854 118778 0.52986731 KDEL (Lys-Asp-Glu- Leu) endoplasmic reticulum protein retention receptor 2 PCO1_HUMAN PCOLCE NM_002593 202097 0.52672595 Procollagen C- endopeptidase enhancer SPRC_HUMAN SPARC NM_003118 111779 0.51922531 Secreted protein, acidic, cysteine-rich (osteonectin) NC5R_HUMAN DIA1 NM_007326 274464 0.51482855 Diaphorase (NADH) (cytochrome b-5 reductase) SEPR_HUMAN FAP NM_004460 418 0.51466336 Fibroblast activation protein, alpha HSAC013564 COL5A1 NM_000093 146428 0.51225806 Collagen, type V, alpha 1 HSAC009848 ZFP93 NM_004234 298089 0.50989391 Zinc finger protein 93 homolog (mouse) PGCV_HUMAN CSPG2 U16306 81800 0.50906177 Chondroitin sulfate proteoglycan 2 (versican) Q14521 LLGL2 NM_004524 3123 −0.50695888 Lethal giant larvae homolog 2 ( Drosophila ) CA14_HUMAN COL4A1 NM_001845 119129 0.50664753 Collagen, type IV, alpha 1 HSAC014709 TEM1 NM_020404 195727 0.50647843 Tumor endothelial marker 1 precursor UROK_HUMAN PLAU NM_002658 77274 0.50439834 Plasminogen activator, urokinase Q8N6P7 IL22R NM_021258 110915 −0.49928496 Interleukin 22 receptor LEG1_HUMAN LGALS1 NM_002305 227751 0.48740219 Lectin, galactoside- binding, soluble, 1 (galectin 1) CA25_HUMAN COL5A2 NM_000393 82985 0.48675513 Collagen, type V, alpha 2 CA13_HUMAN COL3A1 NM_000090 119571 0.48459913 Collagen, type III, alpha 1 (Ehlers-Danlos syndrome type IV, autosomal dominant) Q9BYD5 LOC84518 NM_032488 148590 −0.48449285 Protein related with psoriasis BGH3_HUMAN TGFBI NM_000358 118787 0.48290139 Transforming growth factor, beta-induced, 68 kD CQT6_HUMAN CTRP6 NM_031910 22011 0.47978614 Complement-c1q tumor necrosis factor-related protein 6 AD12_HUMAN ADAM12 NM_003474 8850 0.47905457 A disintegrin and metalloproteinase domain 12 (meltrin alpha) Q8N3N2 FLJ11196 NM_018357 6166 0.47772636 Hypothetical protein FLJ11196 CATK_HUMAN CTSK NM_000396 83942 0.47734967 Cathepsin K (pycnodysostosis) Q96DR2 0 AK055031 44289 −0.47659518 Homo sapiens cDNA FLJ30469 fis, clone BRAWH1000037, weakly similar to UROKINASE PLASMINOGEN ACTIVATO P03996 ACTA2 NM_001613 195851 0.47560995 Actin, alpha 2, smooth muscle, aorta K6A2_HUMAN 0 AK027727 184581 0.47396182 Homo sapiens cDNA FLJ14821 fis, clone OVARC1000556, highly similar to RIBOSOMAL PROTEIN S6 KINASE II Q9HBB0 THY1 AK057865 125359 0.4727028 Thy-1 cell surface antigen TM29_HUMAN TRIM29 NM_012101 82237 −0.47250994 Tripartite motif- containing 29 TIM2_HUMAN 0 AL110197 6441 0.47199573 Homo sapiens mRNA; cDNA DKFZp586J021 (from clone DKFZp586J021) MM02_HUMAN MMP2 NM_004530 111301 0.47026319 Matrix metalloproteinase 2 (gelatinase A, 72 kD gelatinase, 72 kD type IV collagenase) MCA2_HUMAN JTV1 NM_006303 301613 0.46964142 JTV1 gene CA16_HUMAN COL6A1 NM_001848 108885 0.46942561 Collagen, type VI, alpha 1 EVA1_HUMAN EVA1 AF275945 116651 −0.4689165 Epithelial V-like antigen 1 CA21_HUMAN COL1A2 NM_000089 179573 0.46739585 Collagen, type I, alpha 2 CA36_HUMAN COL6A3 NM_004369 80988 0.46507048 Collagen, type VI, alpha 3 OPN3_HUMAN OPN3 NM_014322 279926 0.46101056 Opsin 3 (encephalopsin, panopsin) Q9UBG0 KIAA0709 NM_006039 7835 0.46012143 Endocytic receptor (macrophage mannose receptor family) TPM2_HUMAN TPM2 NM_003289 300772 0.46003075 Tropomyosin 2 (beta) INVO_HUMAN IVL NM_005547 157091 −0.45860578 Involucrin O88386 RAB10 NM_016131 236494 −0.45006586 RAB10, member RAS oncogene family PEPL_HUMAN PPL NM_002705 74304 −0.44874989 Periplakin HSAC002603 FLJ11036 NM_018306 16740 −0.44841185 Hypothetical protein FLJ11036 TNR5_HUMAN TNFRSF5 NM_001250 25648 −0.44547341 Tumor necrosis factor receptor superfamily, member 5 FRIH_HUMAN FTH1 AK054816 62954 0.4396982 Ferritin, heavy polypeptide 1 P4H2_HUMAN P4HA2 NM_004199 3622 0.42478412 Procollagen-proline, 2- oxoglutarate 4- dioxygenase (proline 4- hydroxylase), alpha polypeptide II P09526 RAP1B NM_015646 156764 0.42234208 RAP1B, member of RAS oncogene family PS23_HUMAN SPUVE NM_007173 25338 0.42080095 Protease, serine, 23 HSAC011159 0 AF009267 102238 −0.46560322 Homo sapiens clone FBA1 Cri-du-chat region mRNA SDC2_HUMAN SDC2 J04621 1501 0.45455196 Syndecan 2 (heparan sulfate proteoglycan 1, cell surface-associated, fibroglycan) HSAC013320 0 AL162069 140978 −0.44362782 Homo sapiens mRNA; cDNA DKFZp762H106 (from clone DKFZp762H106) TAGL_HUMAN TAGLN NM_003186 75777 0.4376112 Transgelin MM01_HUMAN MMP1 NM_002421 83169 0.4326825 Matrix metalloproteinase 1 (interstitial collagenase) P05209 K-ALPHA-1 NM_006082 334842 0.42236541 Tubulin, alpha, ubiquitous TSP2_HUMAN THBS2 NM_003247 108623 0.46791583 Thrombospondin 2 Q8N789 DKFZP434K0410 AL137589 152149 −0.43787021 Hypothetical protein DKFZp434K0410 O60335 KIAA0594 AB011166 103283 −0.42578156 KIAA0594 protein P05209 K-ALPHA-1 NM_006082 334842 0.42277793 Tubulin, alpha, ubiquitous TNI3_HUMAN TNFAIP3 NM_006290 211600 0.408128 Tumor necrosis factor, alpha-induced protein 3 FGR1_HUMAN FGFR1 NM_023109 748 0.43553561 Fibroblast growth factor receptor 1 (fms-related tyrosine kinase 2, Pfeiffer syndrome) CAD2_HUMAN CDH2 NM_001792 161 0.3922152 Cadherin 2, type 1, N- cadherin (neuronal) TCOF_HUMAN TCOF1 NM_000356 301266 0.38956707 Treacher Collins- Franceschetti syndrome 1 O14635 0 AF005082 113261 −0.45637623 Homo sapiens skin- specific protein (xp33) mRNA, partial cds GLSK_HUMAN GLS NM_014905 239189 0.43214995 Glutaminase Q9BRJ6 MGC11257 NM_032350 334368 0.42954566 Hypothetical protein MGC11257 ALK1_HUMAN SLPI NM_003064 251754 −0.41872706 Secretory leukocyte protease inhibitor (antileukoproteinase) AQP3_HUMAN AQP3 NM_004925 234642 −0.42891866 Aquaporin 3 SPIB_HUMAN SPIB NM_003121 192861 −0.41021146 Spi-B transcription factor (Spi-1/PU.1 related) P05209 K-ALPHA-1 NM_006082 334842 0.41796901 Tubulin, alpha, ubiquitous DRG1_HUMAN DRG1 NM_004147 115242 0.41879372 Developmentally regulated GTP binding protein 1 PHMX_HUMAN PHEMX NM_005705 271954 0.38728757 Pan-hematopoietic expression P05209 K-ALPHA-1 NM_006082 334842 0.41741385 Tubulin, alpha, ubiquitous HSAC018335 0 AL137428 306459 −0.45404252 Homo sapiens mRNA; cDNA DKFZp761N1323 (from clone DKFZp761N1323) POSN_HUMAN OSF-2 NM_006475 136348 0.42814786 Osteoblast specific factor 2 (fasciclin I-like) DHC3_HUMAN CBR3 NM_001236 154510 −0.48089013 Carbonyl reductase 3 NCR2_HUMAN NCOR2 NM_006312 287994 0.42024512 Nuclear receptor co- repressor 2 HSAC015262 0 AK021531 224398 0.43632187 Homo sapiens cDNA FLJ11469 fis, clone HEMBA1001658 Q14113 AEBP1 NM_001129 118397 0.42087649 AE binding protein 1 TBX2_HUMAN TBX2 AK001031 322856 0.41381789 T-box 2 CRF_HUMAN CRH NM_000756 75294 −0.41353804 Corticotropin releasing hormone Q9NUJ7 FLJ11323 NM_018390 25625 −0.43842923 Hypothetical protein FLJ11323 Q96DU1 AKAP2 AJ303079 42322 −0.44106809 A kinase (PRKA) anchor protein 2 P05209 K-ALPHA-1 NM_006082 334842 0.40736744 Tubulin, alpha, ubiquitous Q969Y7 MGC4677 NM_052871 337986 0.39455354 Hypothetical protein MGC4677 Q9BXY6 FLJ13962 NM_024862 330407 −0.44327759 Hypothetical protein FLJ13962 K1CW_HUMAN HAIK1 NM_015515 9029 −0.42594883 Type I intermediate filament cytokeratin HSAC019114 FLJ22622 NM_025151 324841 −0.4331912 Hypothetical protein FLJ22622 PGS2_HUMAN DCN NM_001920 76152 0.39882715 Decorin DCOP_HUMAN ODC-p NM_052998 91681 −0.41609162 Ornithine decarboxylase-like protein HSAC020747 0 AK056828 350748 −0.40822563 Homo sapiens cDNA FLJ32266 fis, clone PROST1000419 P05209 K-ALPHA-1 NM_006082 334842 0.39997295 Tubulin, alpha, ubiquitous Q96F00 0 AK025719 251664 0.39457176 Homo sapiens cDNA: FLJ22066 fis, clone HEP10611 ISK5_HUMAN SPINK5 NM_006846 331555 −0.43770884 Serine protease inhibitor, Kazal type, 5 GFR1_HUMAN GFRA1 NM_005264 105445 0.37859516 GDNF family receptor alpha 1 AAF24516 NUDEL NM_030808 3850 −0.40726277 LIS1-interacting protein NUDEL; endooligopeptidase A P05209 K-ALPHA-1 NM_006082 334842 0.39594293 Tubulin, alpha, ubiquitous O60836 T1A-2 NM_013317 135150 0.37127534 Lung type-I cell membrane-associated glycoprotein KLKA_HUMAN KLK10 NM_002776 69423 −0.40584943 Kallikrein 10 Q96KC3 MGC3047 NM_032348 59384 0.39922401 Hypothetical protein MGC3047 O95274 C4.4A NM_014400 11950 −0.39942513 GPI-anchored metastasis-associated protein homolog HSAC015726 SERPINB13 AJ001696 241407 −0.41273549 Serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 13 SEN7_HUMAN SENP7 AL136599 30443 −0.37916215 Sentrin/SUMO-specific protease HSAC015968 RPL34P2 AL049714 247903 −0.39984188 Ribosomal protein L34 pseudogene 2 IM8B_HUMAN TIMM8B NM_012459 279915 −0.39646264 Translocase of inner mitochondrial membrane 8 homolog B (yeast) P05209 K-ALPHA-1 NM_006082 334842 0.39265415 Tubulin, alpha, ubiquitous CYTB_HUMAN CSTB NM_000100 695 −0.39593616 Cystatin B (stefin B) MMDP_HUMAN MMD NM_012329 79889 0.35585533 Monocyte to macrophage differentiation- associated Q9H5J1 PREI3 NM_015387 107942 −0.39957843 Preimplantation protein 3 Q9Y283 INVS NM_014425 104715 0.38165914 Inversin S107_HUMAN S100A7 NM_002963 112408 −0.38002947 S100 calcium binding protein A7 (psoriasin 1) SR19_HUMAN SRP19 NM_003135 2943 −0.39927981 Signal recognition particle 19 kD MA17_HUMAN DD96 NM_005764 271473 −0.38289729 Epithelial protein up- regulated in carcinoma, membrane associated protein 17 O75943 RAD17 NM_002873 16184 −0.38971266 RAD17 homolog ( S. pombe ) THA_HUMAN THRA NM_003250 724 0.38475204 Thyroid hormone receptor, alpha (erythroblastic leukemia viral (v-erb-a) oncogene homolog, avian) HSAC008967 0 AK021982 287465 0.38611307 Homo sapiens cDNA FLJ11920 fis, clone HEMBB1000312 TFE2_HUMAN TCF3 M31523 101047 0.38678059 Transcription factor 3 (E2A immunoglobulin enhancer binding factors E12/E47) SUL2_HUMAN KIAA1247 AB033073 43857 0.39182636 Similar to glucosamine- 6-sulfatases HRA3_HUMAN HTRA3 AY040094 60440 0.38043383 Serine protease HTRA3 CN4A_HUMAN PDE4A NM_006202 89901 0.36750244 Phosphodiesterase 4A, cAMP-specific (phosphodiesterase E2 dunce homolog, Drosophila ) LTB2_HUMAN LTBP2 NM_000428 83337 0.36424793 Latent transforming growth factor beta binding protein 2 CSF2_HUMAN CSF2 NM_000758 1349 0.34759785 Colony stimulating factor 2 (granulocyte- macrophage) S109_HUMAN S100A9 NM_002965 112405 −0.38115533 S100 calcium binding protein A9 (calgranulin B) MAL2_HUMAN MAL2 NM_052886 76550 −0.37756452 Mal, T-cell differentiation protein 2 HSAC004288 LANO NM_018214 35091 −0.39020801 LAP (leucine-rich repeats and PDZ) and no PDZ protein P05209 K-ALPHA-1 NM_006082 334842 0.37816007 Tubulin, alpha, ubiquitous EMP3_HUMAN EMP3 NM_001425 9999 0.37961495 Epithelial membrane protein 3 LUM_HUMAN LUM NM_002345 79914 0.36091717 Lumican Q8NC43 FLJ23091 NM_024911 250746 0.4002659 Hypothetical protein FLJ23091 HRA1_HUMAN PRSS11 NM_002775 75111 0.38314991 Protease, serine, 11 (IGF binding) CAH6_HUMAN CA6 NM_001215 100322 0.38495881 Carbonic anhydrase VI SCGF_HUMAN SCGF NM_002975 105927 0.38520465 Stem cell growth factor; lymphocyte secreted C-type lectin CALD_HUMAN CALD1 NM_033138 325474 0.36017333 Caldesmon 1 SYH_HUMAN HARS NM_002109 77798 0.34476889 Histidyl-tRNA synthetase Q8IXQ7 LABH1 NM_032604 98608 0.36012503 Lung alpha/beta hydrolase 1 WEE1_HUMAN WEE1 X62048 75188 −0.38967133 WEE1+ homolog ( S. pombe ) Q9H0B8 DKFZP434B044 NM_031476 262958 0.36902739 Hypothetical protein DKFZp434B044 M1B1_HUMAN MAN1B1 NM_016219 279881 0.37430439 Mannosidase, alpha, class 1B, member 1 FBX8_HUMAN FBXO8 NM_012180 76917 −0.37436238 F-box only protein 8 SM3C_HUMAN SEMA3C NM_006379 171921 0.35697551 Sema domain, immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin) 3C RB25_HUMAN CATX-8 NM_020387 150826 −0.38816294 CATX-8 protein ROL_HUMAN HNRPL NM_001533 2730 0.34146766 Heterogeneous nuclear ribonucleoprotein L FX37_HUMAN MGC11279 NM_024326 10915 −0.38119046 Hypothetical protein MGC11279 HSAC003262 KIAA0350 AB002348 23263 −0.39564135 KIAA0350 protein P05209 K-ALPHA-1 NM_006082 334842 0.37391308 Tubulin, alpha, ubiquitous BTE4_HUMAN KLF16 NM_031918 303194 0.40092333 Kruppel-like factor 16 MK_HUMAN MDK NM_002391 82045 −0.38900237 Midkine (neurite growth-promoting factor 2) Q9NRD9 DUOX1 NM_017434 272813 −0.3913498 Dual oxidase 1 P05209 K-ALPHA-1 NM_006082 334842 0.36936704 Tubulin, alpha, ubiquitous Z185_HUMAN ZNF185 NM_007150 16622 −0.36378851 Zinc finger protein 185 (LIM domain) TBG2_HUMAN TUBG2 NM_016437 279669 0.34203519 Tubulin, gamma 2 AAKC_HUMAN PRKAB2 NM_005399 50732 −0.35738949 Protein kinase, AMP- activated, beta 2 non- catalytic subunit HSAC006508 COL18A1 AF018081 78409 0.37705859 Collagen, type XVIII, alpha 1 Q9BSY6 ZD52F10 NM_033317 32343 −0.37419257 Hypothetical gene ZD52F10 SOX4_HUMAN 0 AJ420500 351928 −0.41521785 Homo sapiens mRNA full length insert cDNA clone EUROIMAGE 1977059 P05209 K-ALPHA-1 NM_006082 334842 0.37198391 Tubulin, alpha, ubiquitous MIC2_HUMAN MIC2 NM_002414 177543 0.36316608 Antigen identified by monoclonal antibodies 12E7, F21 and O13 VWF_HUMAN VWF NM_000552 110802 −0.36187757 Von Willebrand factor MFA5_HUMAN MAGP2 NM_003480 300946 0.34145531 Microfibril-associated glycoprotein-2 ELAF_HUMAN PI3 NM_002638 112341 −0.39367703 Protease inhibitor 3, skin-derived (SKALP) WD13_HUMAN WDR13 NM_017883 12142 0.35576479 WD repeat domain 13 PCB1_HUMAN PCBP1 NM_006196 2853 −0.35199657 Poly(rC) binding protein 1 DYHC_HUMAN DNCH1 AB002323 7720 0.36908919 Dynein, cytoplasmic, heavy polypeptide 1 Q8WUB2 HSU79274 NM_013300 150555 −0.41095099 Protein predicted by clone 23733 Q96N74 PGLYRP NM_052890 282244 −0.37818832 Peptidoglycan recognition protein L precursor HSAC018816 0 AK055723 310919 −0.37825237 Homo sapiens cDNA FLJ31161 fis, clone KIDNE1000028 PPL2_HUMAN PPIL2 NM_014337 93523 −0.34926253 Peptidylprolyl isomerase (cyclophilin)-like 2 HSAC015090 0 AK055294 211132 0.34738745 Homo sapiens cDNA FLJ30732 fis, clone FEBRA2000126, weakly similar to Mus musculus PDZ domain actin P05209 K-ALPHA-1 NM_006082 334842 0.36404497 Tubulin, alpha, ubiquitous DSG3_HUMAN DSG3 NM_001944 1925 −0.35916779 Desmoglein 3 (pemphigus vulgaris antigen) CTGF_HUMAN CTGF NM_001901 75511 0.36449331 Connective tissue growth factor Q96BW1 0 AK056354 91612 0.34964326 Homo sapiens, clone MGC: 23937 IMAGE: 3930177, mRNA, complete cds P05209 K-ALPHA-1 NM_006082 334842 0.36440521 Tubulin, alpha, ubiquitous HSAC020349 0 BC014584 348710 0.33020586 Homo sapiens, clone IMAGE: 4047062, mRNA G3P2_HUMAN GAPD NM_002046 169476 0.36112372 Glyceraldehyde-3- phosphate dehydrogenase DES1_HUMAN DESC1 NM_014058 201877 −0.37199135 DESC1 protein PAI2_HUMAN SERPINB2 NM_002575 75716 −0.39418824 Serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 2 PYG2_HUMAN 0 BC006132 172084 0.36848424 Homo sapiens, clone IMAGE: 3627860, mRNA, partial cds CA17_HUMAN COL7A1 NM_000094 1640 0.35840992 Collagen, type VII, alpha 1 (epidermolysis bullosa, dystrophic, dominant and recessive) Q8NG54 FLJ21212 NM_024642 47099 −0.35274616 Hypothetical protein FLJ21212 Q9H6K5 FLJ22184 NM_025094 288540 −0.36166463 Hypothetical protein FLJ22184 Q96FP4 0 BC010607 104679 0.34999129 Homo sapiens, clone MGC: 18216 IMAGE: 4156235, mRNA, complete cds HSAC019418 0 AK021970 333438 −0.37893723 Homo sapiens cDNA FLJ11908 fis, clone HEMBB1000089 HSAC019917 0 AF130069 343363 −0.34377216 Homo sapiens clone FLB8436 PRO2277 mRNA, complete cds HSAC003296 TACSTD2 NM_002353 23582 −0.3427956 Tumor-associated calcium signal transducer 2 TTC7_HUMAN KIAA1140 AB032966 131728 0.34916061 KIAA1140 protein G3P2_HUMAN GAPD NM_002046 169476 0.35497237 Glyceraldehyde-3- phosphate dehydrogenase Q86VR7 0 BC016993 293236 −0.40258581 Homo sapiens, clone IMAGE: 4401841, mRNA G3P2_HUMAN GAPD NM_002046 169476 0.35582864 Glyceraldehyde-3- phosphate dehydrogenase Q96CG8 0 BC014245 283713 0.34868937 Homo sapiens, Similar to RIKEN cDNA 1110014B07 gene, clone MGC: 20766 IMAGE: 4586039, mRNA, complete c HSAC004760 0 S73288 46320 −0.36573481 Small proline-rich protein SPRK [human, odontogenic keratocysts, mRNA Partial, 317 nt] KLK5_HUMAN KLK5 NM_012427 50915 −0.36794706 Kallikrein 5 SREC_HUMAN SREC NM_003693 57735 0.35910977 Acetyl LDL receptor; SREC Q8IVC7 EPSTI1 NM_033255 343800 −0.35253232 Epithelial stromal interaction 1 (breast) HSAC008195 0 AF339799 174045 −0.36573039 Homo sapiens clone IMAGE: 2363394, mRNA sequence TPM2_HUMAN TPM1 NM_000366 77899 0.3486721 Tropomyosin 1 (alpha) Q9UFS8 AGS3 AL117478 239370 −0.35552159 Likely ortholog of rat activator of G-protein signaling 3 G3P2_HUMAN GAPD NM_002046 169476 0.35209827 Glyceraldehyde-3- phosphate dehydrogenase HSAC011719 CLDN5 NM_003277 110903 −0.35850977 Claudin 5 (transmembrane protein deleted in velocardiofacial syndrome) G3P2_HUMAN GAPD NM_002046 169476 0.34936984 Glyceraldehyde-3- phosphate dehydrogenase HSAC002456 0 AK055225 15167 −0.34350313 Homo sapiens cDNA FLJ30663 fis, clone FCBBF1000598, moderately similar to ZINC FINGER PROTEIN 84 P05209 K-ALPHA-1 NM_006082 334842 0.35175871 Tubulin, alpha, ubiquitous HSAC014332 BENE U17077 185055 −0.36524246 BENE protein G3P2_HUMAN GAPD NM_002046 169476 0.34976822 Glyceraldehyde-3- phosphate dehydrogenase HSAC020817 0 AK055932 350820 −0.36618612 Homo sapiens cDNA FLJ31370 fis, clone NB9N42000122 KLKB_HUMAN KLK11 NM_006853 57771 −0.34648295 Kallikrein 11 AAC1_HUMAN ACTN1 NM_001102 119000 0.33964129 Actinin, alpha 1 G3P2_HUMAN GAPD NM_002046 169476 0.3514833 Glyceraldehyde-3- phosphate dehydrogenase Q8WW05 0 AC006017 131311 −0.34898752 Homo sapiens PAC clone RP5-981O7 from 7q34-q36 HAS3_HUMAN HAS3 AF232772 85962 −0.37055655 Hyaluronan synthase 3 HSAC019767 0 AK022838 336419 −0.35771887 Homo sapiens cDNA FLJ12776 fis, clone NT2RP2001678 O60565 CKTSF1B1 NM_013372 40098 0.33592448 Cysteine knot superfamily 1, BMP antagonist 1 HSAC013123 DKFZp547D065 AL390147 134742 0.35377439 Hypothetical protein DKFZp547D065 G3P2_HUMAN GAPD NM_002046 169476 0.35115594 Glyceraldehyde-3- phosphate dehydrogenase Q14707 KTN1 NM_004986 211577 0.34546179 Kinectin 1 (kinesin receptor) HSAC001617 UCRP AF388367 8201 −0.32315934 Usher critical region protein pseudogene HSAC017169 0 AL137617 274583 −0.36507656 Homo sapiens mRNA; cDNA DKFZp434C0512 (from clone DKFZp434C0512) Q9H7K0 0 AK024480 13766 −0.35542828 Homo sapiens mRNA for FLJ00074 protein, partial cds G3P2_HUMAN GAPD NM_002046 169476 0.34999375 Glyceraldehyde-3- phosphate dehydrogenase HSAC015798 0 AK000745 243901 0.33333793 Homo sapiens mRNA; cDNA DKFZp564C1563 (from clone DKFZp564C1563) CLH1_HUMAN CLTC NM_004859 178710 0.33305718 Clathrin, heavy polypeptide (Hc) PAI1_HUMAN SERPINE1 NM_000602 82085 0.32335137 Serine (or cysteine) proteinase inhibitor, clade E (nexin, plasminogen activator inhibitor type 1), HSAC018152 0 AK057719 303105 −0.33343853 Homo sapiens cDNA FLJ33157 fis, clone UTERU2000393 HSAC019360 0 AK024104 333154 −0.33563282 Homo sapiens cDNA FLJ14042 fis, clone HEMBA1006038, weakly similar to LAMININ ALPHA-5 CHAIN Q9H7E9 FLJ20989 NM_023080 169615 0.33185124 Hypothetical protein FLJ20989 TGF1_HUMAN TGFB1 NM_000660 1103 0.36859438 Transforming growth factor, beta 1 Q9NRA1 PDGFC NM_016205 43080 0.33440168 Platelet derived growth factor C HSAC020279 0 BC014381 348523 −0.38018709 Homo sapiens, clone IMAGE: 4046329, mRNA Q8IXK0 EDR2 NM_004427 165263 0.3333879 Early development regulator 2 (polyhomeotic 2 homolog) HSAC017377 PRO0514 NM_014131 278939 −0.32206704 PRO0514 protein Q9BPY8 SMAP31 NM_032495 13775 −0.39460445 Hypothetical protein SMAP31 MT70_HUMAN M6A NM_019852 268149 0.35349822 Putative methyltransferase UDP2_HUMAN UGP2 NM_006759 77837 0.32421497 UDP-glucose pyrophosphorylase 2 O00205 SULT2B1 NM_004605 94581 −0.36104276 Sulfotransferase family, cytosolic, 2B, member 1 Q96A75 PGS1 NM_024419 278682 0.33507703 Phosphatidylglycerophosphate Synthase PI4K_HUMAN PIK4CA NM_058004 334874 0.32401638 Phosphatidylinositol 4- kinase, catalytic, alpha polypeptide SPT1_HUMAN SPINT1 NM_003710 233950 −0.34424419 Serine protease inhibitor, Kunitz type 1 TGM1_HUMAN TGM1 NM_000359 22 −0.36535457 Transglutaminase 1 (K polypeptide epidermal type I, protein- glutamine-gamma- glutamyltransferase) FPGT_HUMAN FPGT NM_003838 150926 −0.334427 Fucose-1-phosphate guanylyltransferase Q9H3D4 TP63 Y16961 137569 −0.33233956 Tumor protein 63 kDa with strong homology to p53 G3P2_HUMAN GAPD NM_002046 169476 0.3376594 Glyceraldehyde-3- phosphate dehydrogenase TENA_HUMAN HXB NM_002160 289114 0.31189127 Hexabrachion (tenascin C, cytotactin) OAS1_HUMAN OAS1 NM_016816 82396 −0.34392735 2′,5′-oligoadenylate synthetase 1 (40-46 kD) Q969E4 MGC15737 NM_032926 39122 0.34380675 Hypothetical protein MGC15737 G3P2_HUMAN GAPD NM_002046 169476 0.33818775 Glyceraldehyde-3- phosphate dehydrogenase IL6_HUMAN IL6 NM_000600 93913 0.30335363 Interleukin 6 (interferon, beta 2) LMB3_HUMAN LAMB3 NM_000228 75517 0.32051769 Laminin, beta 3 (nicein (125 kD), kalinin (140 kD), BM600 (125 kD)) HSAC015555 DKFZp761K1423 NM_018422 236438 −0.33416824 Hypothetical protein DKFZp761K1423 BASP_HUMAN BASP1 NM_006317 79516 0.3230565 Brain abundant, membrane attached signal protein 1 Q8NG12 FLJ22792 NM_024921 267038 −0.36618724 Hypothetical protein FLJ22792 Q99603 TRG@ AK056843 112259 −0.36306016 T cell receptor gamma locus TDE2_HUMAN KIAA1253 AB033079 146668 0.32859657 KIAA1253 protein ALC1_HUMAN IGHM X58529 293441 0.30789147 Immunoglobulin heavy constant mu G3P2_HUMAN GAPD NM_002046 169476 0.338632 Glyceraldehyde-3- phosphate dehydrogenase KCC1_HUMAN CAMK1 NM_003656 184402 0.32331521 Calcium/calmodulin- dependent protein kinase I Q8NCP6 GLE1L NM_001499 169363 0.33812915 GLE1 RNA export mediator-like (yeast) COM5_HUMAN HT002 AK023070 238928 0.31500738 HT002 protein; hypertension-related calcium-regulated gene HSAC001787 SPC18 NM_014300 9534 0.32516848 Signal peptidase complex (18 kD) HSAC020210 0 BC012014 348340 0.32291489 Homo sapiens, clone IMAGE: 4509827, mRNA, partial cds Q96AL8 0 BC016969 7155 −0.36007634 Homo sapiens, clone IMAGE: 4428577, mRNA, partial cds PEDF_HUMAN SERPINF1 NM_002615 173594 0.3214249 Serine (or cysteine) proteinase inhibitor, clade F (alpha-2 antiplasmin, pigment epithelium derived GA15_HUMAN DDIT3 NM_004083 337761 0.30554219 DNA-damage-inducible transcript 3 NGAL_HUMAN LCN2 NM_005564 204238 −0.34145982 Lipocalin 2 (oncogene 24p3) RHOC_HUMAN ARHC NM_005167 179735 0.35111593 Ras homolog gene family, member C G3P2_HUMAN GAPD NM_002046 169476 0.33567842 Glyceraldehyde-3- phosphate dehydrogenase O95491 DNAH11 NM_003777 349084 −0.37201261 Dynein, axonemal, heavy polypeptide 11 NIF3_HUMAN NLI-IF NM_021198 283724 0.341321 Nuclear LIM interactor- interacting factor Q96MC2 0 AK057222 123428 −0.36359079 Homo sapiens, Similar to CG10958 gene product, clone MGC: 16372 IMAGE: 3929220, mRNA, complete cds KVB1_HUMAN KCNAB1 AK057059 172471 −0.32465311 Potassium voltage- gated channel, shaker- related subfamily, beta member 1 P20172 AP2M1 NM_004068 152936 0.33712949 Adaptor-related protein complex 2, mu 1 subunit CDX1_HUMAN CDX1 NM_001804 1545 0.32711759 Caudal type homeo box transcription factor 1 G3P2_HUMAN GAPD NM_002046 169476 0.32910404 Glyceraldehyde-3- phosphate dehydrogenase LCFD_HUMAN FACL4 NM_022977 81452 −0.33567272 Fatty-acid-Coenzyme A ligase, long-chain 4 Q9NX63 FLJ20420 NM_017812 6693 −0.34188068 Hypothetical protein FLJ20420 IBP7_HUMAN IGFBP7 NM_001553 119206 0.32895548 Insulin-like growth factor binding protein 7 HSAC018498 0 AK024867 306710 −0.35579721 Homo sapiens cDNA: FLJ21214 fis, clone COL00523 HSAC009099 0 AK024849 287650 −0.33929018 Homo sapiens cDNA: FLJ21196 fis, clone COL00193 Q8IYN2 0 AK026349 288361 0.32392521 Homo sapiens cDNA: FLJ22696 fis, clone HSI11696 Q96ML0 0 AK056768 310758 −0.36516521 Homo sapiens cDNA FLJ32206 fis, clone PLACE6003109 HSAC001114 0 AL137723 5855 −0.35802784 Homo sapiens mRNA; cDNA DKFZp434D0818 (from clone DKFZp434D0818) HSAC019203 0 AF339829 326716 −0.3385585 Homo sapiens clone IMAGE: 609847, mRNA sequence IF42_HUMAN EIF4A2 NM_001967 173912 0.32373865 Eukaryotic translation initiation factor 4A, isoform 2 HSAC013605 0 AL512697 147587 −0.3486998 Homo sapiens mRNA; cDNA DKFZp547F134 (from clone DKFZp547F134) Q96N43 0 AK055994 28345 −0.3643947 Homo sapiens cDNA FLJ25084 fis, clone CBL08511 O94781 LAMP3 NM_014398 10887 −0.3448522 Lysosomal-associated membrane protein 3 Q8N336 DKFZp547C176 AL359601 48448 −0.32503335 Hypothetical protein DKFZp547C176 BAC1_HUMAN BACH1 NM_001186 154276 −0.34061833 BTB and CNC homology 1, basic leucine zipper transcription factor 1 G3P2_HUMAN GAPD NM_002046 169476 0.32785053 Glyceraldehyde-3- phosphate dehydrogenase FX32_HUMAN 0 NM_058229 61661 0.30830001 Homo sapiens cDNA FLJ32424 fis, clone SKMUS2000954, moderately similar to Homo sapiens F-box protein DSC2_HUMAN DSC2 NM_004949 239727 −0.34044888 Desmocollin 2 K2CE_HUMAN KRT6B NM_005555 335952 −0.31728346 Keratin 6B ANXB_HUMAN ANXA11 NM_001157 75510 −0.30741089 Annexin A11 Q9BZC1 BRUNOL4 NM_020180 41641 0.30753295 Bruno-like 4, RNA binding protein ( Drosophila ) MYPH_HUMAN MYBPH NM_004997 927 0.28279614 Myosin binding protein H ETFA_HUMAN ETFA NM_000126 169919 −0.31059939 Electron-transfer- flavoprotein, alpha polypeptide (glutaric aciduria II) EMP2_HUMAN EMP2 NM_001424 29191 −0.31207607 Epithelial membrane protein 2 O95712 PLA2G4B NM_005090 198161 −0.37069629 Phospholipase A2, group IVB (cytosolic) HSAC020830 0 AK055817 350833 −0.30730506 Homo sapiens cDNA FLJ31255 fis, clone KIDNE2005603, moderately similar to 2- OXOGLUTARATE DEHYDROGENA LOL1_HUMAN LOXL1 NM_005576 65436 0.30369668 Lysyl oxidase-like 1 HSAC007550 0 AK056805 162859 0.30195444 Homo sapiens cDNA FLJ32243 fis, clone PROST1000039 HPC1_HUMAN HPCAL1 NM_002149 3618 −0.3406495 Hippocalcin-like 1 Q9H5G9 FLJ23447 NM_024825 175024 −0.34322107 Hypothetical protein FLJ23447 RSG4_HUMAN RASAL1 NM_004658 198312 −0.36721309 RAS protein activator like 1 (GAP1 like) HSAC009467 0 AK021980 289068 0.28867038 Homo sapiens cDNA FLJ11918 fis, clone HEMBB1000272 Q9BXL5 EDAG-1 NM_018437 176626 −0.29674005 Hypothetical protein EDAG-1 Q96HM7 0 BC016154 350580 0.32162091 Homo sapiens, clone MGC: 13247 IMAGE: 4040497, mRNA, complete cds HSAC014243 0 AK057730 184050 −0.34785224 Homo sapiens cDNA FLJ25001 fis, clone CBL00443 Q9NSU6 0 AL137734 149356 −0.31041517 Homo sapiens mRNA; cDNA DKFZp586C0721 (from clone DKFZp586C0721); partial cds Q9UHJ4 KV8.1 NM_014379 13285 −0.32573332 Neuronal potassium channel alpha subunit SPSY_HUMAN SMS NM_004595 89718 0.30387323 Spermine synthase HSAC003848 0 AL050204 28540 −0.32209004 Homo sapiens mRNA; cDNA DKFZp586F1223 (from clone DKFZp586F1223) Q8NG17 0 AK057423 344530 −0.32147722 Homo sapiens cDNA FLJ32861 fis, clone TESTI2003589 Q9Y6H1 LOC51142 NM_016139 180859 0.28850691 16.7 Kd protein Q8TCZ2 DKFZP761H2024 NM_031462 169388 0.29944756 Hypothetical protein DKFZp761H2024 MAT3_HUMAN MATR3 NM_018834 78825 0.33085933 Matrin 3 TG37_HUMAN TG737 NM_006531 2291 −0.31723327 Probe hTg737 (polycystic kidney disease, autosomal recessive, in) TRIO_HUMAN TRIO NM_007118 171957 0.3112166 Triple functional domain (PTPRF interacting) PIMT_HUMAN PCMT1 NM_005389 79137 0.30318248 Protein-L-isoaspartate (D-aspartate) O- methyltransferase HSAC018541 0 AK025055 306756 0.29732767 Homo sapiens cDNA: FLJ21402 fis, clone COL03734 FXO4_HUMAN MLLT7 NM_005938 239663 −0.3275796 Myeloid/lymphoid or mixed-lineage leukemia (trithorax homolog, Drosophila ); translocated to, 7 HSAC005508 LOC57099 NM_020371 63168 −0.31221717 Cell death regulator aven HSAC013183 0 AL049328 135642 −0.30015385 Homo sapiens mRNA; cDNA DKFZp564E026 (from clone DKFZp564E026) JAK1_HUMAN JAK1 NM_002227 50651 −0.32933441 Janus kinase 1 (a protein tyrosine kinase) HSAC018490 0 AK024712 306702 −0.32269088 Homo sapiens cDNA: FLJ21059 fis, clone CAS00740 NHR1_HUMAN SLC9A3R1 NM_004252 184276 −0.32298859 Solute carrier family 9 (sodium/hydrogen exchanger), isoform 3 regulatory factor 1 HSAC018263 0 AL109730 306331 0.30249865 Homo sapiens mRNA full length insert cDNA clone EUROIMAGE 68600 IRK3_HUMAN KCNJ3 NM_002239 37169 −0.27575989 Potassium inwardly- rectifying channel, subfamily J, member 3 CTR1_HUMAN 0 AL050021 14846 −0.29584263 Homo sapiens mRNA; cDNA DKFZp564D016 (from clone DKFZp564D016) FAN_HUMAN NSMAF NM_003580 78687 0.31613497 Neutral sphingomyelinase (N- SMase) activation associated factor Q96NA9 MEG3 AK055725 112844 0.25180621 Maternally expressed 3 HSAC020071 0 AK057520 345390 −0.33442472 Homo sapiens cDNA FLJ32958 fis, clone TESTI2008234 EML1_HUMAN EMAPL NM_004434 12451 0.29532372 Echinoderm microtubule-associated protein-like O75915 JWA NM_006407 92384 0.3125817 Vitamin A responsive; cytoskeleton related TRKB_HUMAN 0 AJ420458 351930 −0.30975194 Homo sapiens mRNA full length insert cDNA clone EUROIMAGE 1630957 Q9P1S1 FLJ10116 NM_018000 79741 −0.30735296 Hypothetical protein FLJ10116 Q96B21 0 BC016153 283552 −0.31888744 Homo sapiens, Similar to hypothetical protein FLJ10134, clone MGC: 13208 IMAGE: 3841102, mRNA, complet RB3D_HUMAN GOV AF019226 8036 −0.30399168 Glioblastoma overexpressed CGD1_HUMAN CCND1 NM_053056 82932 0.2829885 Cyclin D1 (PRAD1: parathyroid adenomatosis 1) NPS1_HUMAN NIPSNAP1 NM_003634 173878 0.29229903 Nipsnap homolog 1 ( C. elegans ) COR3_HUMAN SPRR3 NM_005416 139322 −0.33687812 Small proline-rich protein 3 LDHA_HUMAN LDHA NM_005566 2795 0.30841977 Lactate dehydrogenase A KPCI_HUMAN PRKCI NM_002740 1904 −0.32314399 Protein kinase C, iota IF42_HUMAN EIF4A2 NM_001967 173912 0.28965638 Eukaryotic translation initiation factor 4A, isoform 2 HSAC009161 0 AK026955 287737 0.30940785 Homo sapiens cDNA: FLJ23302 fis, clone HEP11143 PLE1_HUMAN PLEC1 NM_000445 79706 0.30274257 Plectin 1, intermediate filament binding protein, 500 kD HSAC014877 0 BE961032 200400 −0.2926312 Human DNA sequence from BAC 15E1 on chromosome 12. Contains Cytochrome C Oxidase Polypeptide VIa-liv O94920 KIAA0831 NM_014924 103000 −0.34631714 KIAA0831 protein ACBP_HUMAN DBI NM_020548 78888 −0.31289222 Diazepam binding inhibitor (GABA receptor modulator, acyl-Coenzyme A binding protein) HSAC000440 HBP17 NM_005130 1690 −0.28350117 Heparin-binding growth factor binding protein MY10_HUMAN MYO10 NM_012334 61638 0.28091339 Myosin X CP2B_HUMAN CYP27B1 NM_000785 199270 0.28232127 Cytochrome P450, subfamily XXVIIB (25- hydroxyvitamin D-1- alpha-hydroxylase), polypeptide 1 HSAC007525 0 AL133568 161454 0.27850204 Homo sapiens mRNA; cDNA DKFZp434N197 (from clone DKFZp434N197) Q9BV47 MGC1136 NM_024025 8719 0.27658422 Hypothetical protein MGC1136 IHA_HUMAN INHA NM_002191 1734 0.28237705 Inhibin, alpha COXM_HUMAN COX7B NM_001866 75752 −0.29046875 Cytochrome c oxidase subunit VIIb SM4D_HUMAN SEMA4D NM_006378 79089 −0.29092767 Sema domain, immunoglobulin domain (Ig), transmembrane domain (TM) and short cytoplasmic domain, (se SZ06_HUMAN SCYB6 NM_002993 164021 0.25934353 Small inducible cytokine subfamily B (Cys-X-Cys), member 6 (granulocyte chemotactic protein 2) DTNA_HUMAN 0 AK054766 351299 0.25246747 Homo sapiens cDNA FLJ30204 fis, clone BRACE2001496 Q9H668 FLJ22559 NM_024928 273387 0.27961608 Hypothetical protein FLJ22559 LDHA_HUMAN LDHA NM_005566 2795 0.30032227 Lactate dehydrogenase A LDHA_HUMAN LDHA NM_005566 2795 0.30160612 Lactate dehydrogenase A Q8NAZ8 MAIL NM_031419 301183 −0.32420971 Molecule possessing ankyrin repeats induced by lipopolysaccharide (MAIL), homolog of mouse CBX3_HUMAN CBX3 NM_016587 278554 0.28827974 Chromobox homolog 3 (HP1 gamma homolog, Drosophila ) CLF6_HUMAN FLJ20396 NM_017801 283685 0.30443015 Hypothetical protein FLJ20396 Q9Y4H4 C6orf9 NM_022107 288316 0.3070718 Chromosome 6 open reading frame 9 HSAC018947 FLJ10257 AK001119 321149 0.25119607 Hypothetical protein FLJ10257 O60687 SRPUL NM_014467 126782 0.3005592 Sushi-repeat protein ETV6_HUMAN ETV6 NM_001987 169081 0.28814409 Ets variant gene 6 (TEL oncogene) BIR2_HUMAN BIRC2 NM_001166 289107 0.27998085 Baculoviral IAP repeat- containing 2 IRS2_HUMAN IRS2 AF073310 143648 0.26611452 Insulin receptor substrate 2 L10K_HUMAN HSPC023 NM_014047 279945 0.28479353 HSPC023 protein HSAC017376 0 BF541376 278937 0.27795661 ESTs, Weakly similar to FRHUL ferritin light chain [ H. sapiens ] LDHA_HUMAN LDHA NM_005566 2795 0.29743949 Lactate dehydrogenase A D103_HUMAN DEFB3 NM_018661 283082 −0.32396031 Defensin, beta 3 Q9BUC9 DAP NM_004394 75189 0.30044109 Death-associated protein Q9BSU0 FLJ22457 NM_024901 238707 −0.29867151 Hypothetical protein FLJ22457 LDHA_HUMAN LDHA NM_005566 2795 0.29428289 Lactate dehydrogenase A TPTE_HUMAN TPTE NM_013315 122986 0.29338232 Transmembrane phosphatase with tensin homology HSAC018269 0 AL110206 306339 0.29149163 Homo sapiens mRNA; cDNA DKFZp586N2022 (from clone DKFZp586N2022) Q8WWY3 PRPF31 NM_015629 183438 0.28992597 PRP31 pre-mRNA processing factor 31 homolog (yeast) Q9NWG1 SDCCAG1 NM_004713 54900 0.27325851 Serologically defined colon cancer antigen 1 ID1_HUMAN ID1 NM_002165 75424 −0.30300715 Inhibitor of DNA binding 1, dominant negative helix-loop- helix protein HSAC018258 0 AL080208 306325 −0.32407958 Homo sapiens mRNA; cDNA DKFZp586C1523 (from clone DKFZp586C1523) E2F5_HUMAN E2F5 NM_001951 2331 −0.32253572 E2F transcription factor 5, p130-binding GPX7_HUMAN CL683 NM_015696 43728 0.27876425 Weakly similar to glutathione peroxidase 2 AMD1_HUMAN AMPD1 NM_000036 89570 0.30648359 Adenosine monophosphate deaminase 1 (isoform M) SDC1_HUMAN SDC1 NM_002997 82109 −0.29681828 Syndecan 1 HSAC010708 FLJ10852 NM_019028 95744 −0.27932774 Hypothetical protein similar to ankyrin repeat-containing priotein AKR1 HSAC016387 0 AK023404 255890 −0.30644116 Homo sapiens cDNA FLJ13342 fis, clone OVARC1001950 MU81_HUMAN MUS81 NM_025128 288798 0.30225775 MUS81 endonuclease LDHA_HUMAN LDHA NM_005566 2795 0.29433701 Lactate dehydrogenase A NFC2_HUMAN NFATC2 NM_012340 248037 −0.28597821 Nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 2 CAV2_HUMAN CAV2 NM_001233 139851 0.28575252 Caveolin 2 HSAC012923 0 AK024243 130874 −0.30558024 Homo sapiens cDNA FLJ14181 fis, clone NT2RP2004300 RAG2_HUMAN RAG2 AF080577 159376 0.27054284 Recombination activating gene 2 HSAC001602 TOM1L2 AK055959 8125 −0.30209679 Target of myb1-like 2 (chicken) HSAC013938 FLJ11585 NM_023075 154145 −0.27045129 Hypothetical protein FLJ11585 WNT3_HUMAN WNT3 NM_030753 224667 −0.22616384 Wingless-type MMTV integration site family, member 3 P02570 ACTB NM_001101 288061 0.30930373 Actin, beta Y469_HUMAN KIAA0469 NM_014851 7764 −0.27875891 KIAA0469 gene product ALDR_HUMAN AKR1B1 NM_001628 75313 0.24791515 Aldo-keto reductase family 1, member B1 (aldose reductase) HSAC003731 0 AK023559 27091 −0.30440343 Homo sapiens cDNA FLJ13497 fis, clone PLACE1004518 Q9Y605 PGR1 NM_033296 285902 0.23312692 T-cell activation protein KFP3_HUMAN KIFAP3 NM_014970 171374 0.29438383 Kinesin-associated protein 3 LDHA_HUMAN LDHA NM_005566 2795 0.29008023 Lactate dehydrogenase A HSAC016288 0 AL080073 251414 −0.27036219 Homo sapiens mRNA; cDNA DKFZp564B1462 (from clone DKFZp564B1462) HSAC003517 0 AL133611 25362 −0.29482254 Homo sapiens mRNA; cDNA DKFZp434O1317 (from clone DKFZp434O1317) CPG2_HUMAN LOC51137 NM_016128 102950 −0.27178678 Coat protein gamma- cop TS22_HUMAN TSC22 AK027071 114360 0.2800433 Transforming growth factor beta-stimulated protein TSC-22 S108_HUMAN S100A8 NM_002964 100000 −0.30596008 S100 calcium binding protein A8 (calgranulin A) GLGB_HUMAN GBE1 NM_000158 1691 −0.28462395 Glucan (1,4-alpha-), branching enzyme 1 (glycogen branching enzyme, Andersen disease, glycogen stora TCPZ_HUMAN CCT6A NM_001762 82916 0.26946642 Chaperonin containing TCP1, subunit 6A (zeta 1) NUDM_HUMAN NDUFA10 NM_004544 198271 0.26779732 NADH dehydrogenase (ubiquinone) 1 alpha subcomplex, 10 (42 kD) Q9P005 HSPC159 NM_014181 114771 −0.29780343 HSPC159 protein HSAC013665 0 BC009462 149596 −0.30540195 Homo sapiens, Similar to RIKEN cDNA 2310038H17 gene, clone MGC: 15974 IMAGE: 3542748, mRNA, complete c LDHA_HUMAN LDHA NM_005566 2795 0.29038588 Lactate dehydrogenase A Q96B64 C1orf29 NM_006820 75470 −0.28141634 Chromosome 1 open reading frame 29 OSB2_HUMAN OSBP2 AF288741 7740 −0.2741057 Oxysterol binding protein 2 IMD2_HUMAN IMPDH2 NM_000884 75432 0.25505345 IMP (inosine monophosphate) dehydrogenase 2 NID2_HUMAN NID2 NM_007361 82733 0.2691638 Nidogen 2 HSAC019850 0 AJ420542 339283 −0.30808045 Homo sapiens mRNA full length insert cDNA clone EUROIMAGE 1090104 Q8WW54 LOC51326 NM_016632 264509 0.27687084 ARF protein ELM1_HUMAN ELMO1 AL136787 31463 −0.27259252 Engulfment and cell motility 1 (ced-12 homolog, C. elegans ) HSAC014487 KIAA1733 AB051520 191979 −0.26781459 KIAA1733 protein ENOB_HUMAN ENO3 NM_001976 118804 0.26094659 Enolase 3, (beta, muscle) LDHA_HUMAN LDHA NM_005566 2795 0.29558421 Lactate dehydrogenase A OM07_HUMAN LOC54543 AK027539 112318 0.28422476 6.2 kd protein HSAC003197 0 AK025726 22867 −0.28883729 Homo sapiens cDNA: FLJ22073 fis, clone HEP11868 Q92922 SMARCC1 NM_003074 172280 −0.28726269 SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily c, member 1 Q9Y2F1 KIAA0942 NM_015310 6763 −0.28114819 KIAA0942 protein SIVA_HUMAN SIVA NM_006427 112058 0.2653505 CD27-binding (Siva) protein LMA3_HUMAN LAMA3 NM_000227 83450 0.25310579 Laminin, alpha 3 (nicein (150 kD), kalinin (165 kD), BM600 (150 kD), epilegrin) HSAC010931 0 AK054565 99014 0.2461665 Homo sapiens , clone IMAGE: 3632168, mRNA ALM1_HUMAN ABLIM NM_002313 158203 −0.29500492 Actin binding LIM protein TKNK_HUMAN TAC3 NM_013251 9730 0.2856172 Tachykinin 3 (neuromedin K, neurokinin beta) HPS3_HUMAN HPS3 AY033141 282804 −0.32252959 Hermansky-Pudlak syndrome 3 HSAC021198 0 AK055550 351640 −0.2982647 Homo sapiens cDNA FLJ30988 fis, clone HLUNG1000030 Q9H657 FLJ22593 NM_024703 101265 0.28723669 Hypothetical protein FLJ22593 Q14244 MAP7 NM_003980 146388 −0.26283399 Microtubule-associated protein 7 SPB7_HUMAN SERPINB7 NM_003784 138202 −0.33063598 Serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 7 TR1A_HUMAN TNFRSF1A NM_001065 159 0.28778288 Tumor necrosis factor receptor superfamily, member 1A TPP2_HUMAN TPP2 NM_003291 1117 −0.28378443 Tripeptidyl peptidase II RU17_HUMAN SNRP70 NM_003089 174051 0.30742876 Small nuclear ribonucleoprotein 70 kD polypeptide (RNP antigen) RB6A_HUMAN RAB6A AK057157 5636 −0.3002715 RAB6A, member RAS oncogene family NDKB_HUMAN NME2 NM_002512 275163 0.27328053 Non-metastatic cells 2, protein (NM23B) expressed in KU70_HUMAN G22P1 NM_001469 197345 0.27324664 Thyroid autoantigen 70 kD (Ku antigen) Q8IVU3 FLJ20637 NM_017912 179669 −0.27130275 Hypothetical protein FLJ20637 TPSN_HUMAN TAPBP AF029750 179600 −0.26528001 TAP binding protein (tapasin) ZEP1_HUMAN HIVEP1 NM_002114 306 0.25935225 Human immunodeficiency virus type I enhancer binding protein 1 Q9H8B3 0 AK023854 154751 −0.28222739 Homo sapiens cDNA FLJ13792 fis, clone THYRO1000072, weakly similar to MYOSIN LIGHT CHAIN KINASE, SMO HSAC018635 0 AK026731 306873 −0.26370149 Homo sapiens cDNA: FLJ23078 fis, clone LNG05870 HSAC018455 0 AK024098 306663 −0.25828945 Homo sapiens cDNA FLJ14036 fis, clone HEMBA1004709 ECG2_HUMAN ECG2 NM_032566 244569 −0.36634539 Esophagus cancer- related gene-2 DLK_HUMAN DLK1 NM_003836 169228 −0.29226303 Delta-like 1 homolog ( Drosophila ) LDHA_HUMAN LDHA NM_005566 2795 0.29093325 Lactate dehydrogenase A CRTC_HUMAN CALR NM_004343 16488 0.26036309 Calreticulin HSAC013371 LOC51087 NM_015982 142989 0.2559957 Germ cell specific Y- box binding protein HSAC011127 0 AL133645 101651 −0.30011435 Homo sapiens mRNA; cDNA DKFZp434C107 (from clone DKFZp434C107) BAA09603 DJ-1 NM_007262 10958 0.2951662 RNA-binding protein regulatory subunit ATF7_HUMAN ATF7 NM_006856 55888 −0.28947132 Activating transcription factor 7 RHG6_HUMAN ARHGAP6 NM_001174 250830 −0.28626769 Rho GTPase activating protein 6 EPOR_HUMAN EPOR NM_000121 89548 −0.27351061 Erythropoietin receptor SN23_HUMAN SNAP23 BC003686 184376 0.26960802 Synaptosomal- associated protein, 23 kD HSAC018299 0 AK000293 306391 −0.26323331 Homo sapiens cDNA FLJ20286 fis, clone HEP04358 AMD_HUMAN PAM NM_000919 83920 0.2573707 Peptidylglycine alpha- amidating monooxygenase MAGC_HUMAN MAGEA12 NM_005367 169246 0.23080255 Melanoma antigen, family A, 12 HSAC011887 0 AK021693 113660 0.28054849 Homo sapiens cDNA FLJ11631 fis, clone HEMBA1004267 HSAC002243 0 U80766 13252 0.28054079 Human EST clone 22453 mariner transposon Hsmar1 sequence LDHA_HUMAN LDHA NM_005566 2795 0.28016177 Lactate dehydrogenase A HSAC015540 0 AK021431 235543 −0.27184922 Homo sapiens cDNA FLJ11369 fis, clone HEMBA1000338 VTNC_HUMAN VTN NM_000638 2257 0.26296734 Vitronectin (serum spreading factor, somatomedin B, complement S-protein) RS4Y_HUMAN RPS4Y NM_001008 180911 0.25349604 Ribosomal protein S4, Y-linked Q9NXV4 FLJ20038 AL117436 72071 0.2341145 Hypothetical protein FLJ20038 LDHA_HUMAN LDHA NM_005566 2795 0.28721692 Lactate dehydrogenase A RT36_HUMAN MRPS36 NM_033281 41182 −0.27224936 Mitochondrial ribosomal protein S36 HSAC016670 0 AF127771 269645 −0.24620011 Homo sapiens cell-line E8CASS clone E24L estradiol-induced mRNA sequence HS71_HUMAN HSPA1A NM_005345 8997 0.23168516 Heat shock 70 kD protein 1A SPCQ_HUMAN SPTBN4 NM_025213 32706 −0.3053758 Spectrin, beta, non- erythrocytic 4 Q00007 PPP2R2A NM_002717 179574 −0.29293379 Protein phosphatase 2 (formerly 2A), regulatory subunit B (PR 52), alpha isoform P02570 ACTB NM_001101 288061 0.28900489 Actin, beta PSS1_HUMAN PTDSS1 NM_014754 77329 0.27454166 Phosphatidylserine synthase 1 RBP1_HUMAN RALBP1 NM_006788 75447 −0.26200162 RalA binding protein 1 Q86WL8 0 AK055310 65771 −0.25500063 Homo sapiens cDNA FLJ30748 fis, clone FEBRA2000399, moderately similar to ZINC FINGER PROTEIN 45 HSAC017300 0 AL137712 278565 0.24979685 Homo sapiens mRNA; cDNA DKFZp434H0923 (from clone DKFZp434H0923) SPL1_HUMAN SPARCL1 NM_004684 75445 0.26009914 SPARC-like 1 (mast9, hevin) Q13018 PLA2R1 U17033 171945 −0.25693813 Phospholipase A2 receptor 1, 180 kD Q9NPE2 NEUGRIN NM_016645 323467 0.23781654 Mesenchymal stem cell protein DSC92 Q9H652 MGC4171 NM_024307 289015 −0.32024804 Hypothetical protein MGC4171 K22E_HUMAN KRT2A NM_000423 707 −0.2888545 Keratin 2A (epidermal ichthyosis bullosa of Siemens) KPT2_HUMAN PCTK2 NM_002595 183302 −0.28303243 PCTAIRE protein kinase 2 Q96B23 0 BC016149 33862 −0.27418789 Homo sapiens , clone MGC: 12909 IMAGE: 4040087, mRNA, complete cds DAF_HUMAN DAF NM_000574 1369 −0.27270806 Decay accelerating factor for complement (CD55, Cromer blood group system) Q09753 DEFB1 NM_005218 32949 −0.26188185 Defensin, beta 1 HSAC001158 0 AK026673 6127 0.25225961 Homo sapiens cDNA: FLJ23020 fis, clone LNG00943 DECR_HUMAN DECR1 NM_001359 81548 0.24937384 2,4-dienoyl CoA reductase 1, mitochondrial CIT2_HUMAN CITED2 AF109161 82071 −0.24627852 Cbp/p300-interacting transactivator, with Glu/Asp-rich carboxy- terminal domain, 2 IPO4_HUMAN FLJ23338 NM_024658 61790 0.21814335 Hypothetical protein FLJ23338 HSAC009416 0 AK023616 288949 0.27291917 Homo sapiens cDNA FLJ13554 fis, clone PLACE1007478 SPEE_HUMAN SRM NM_003132 76244 0.26205253 Spermidine synthase GLT2_HUMAN GALNT2 NM_004481 130181 0.25166558 UDP-N-acetyl-alpha-D- galactosamine:polypeptide N- acetylgalactosaminyltransferase 2 (GalNAc- T2) EF1G_HUMAN EEF1G BC004215 2186 0.24251596 Eukaryotic translation elongation factor 1 gamma IF42_HUMAN EIF4A2 NM_001967 173912 0.22487428 Eukaryotic translation initiation factor 4A, isoform 2 Q9P221 FLJ20654 AB040940 5131 −0.21966498 Hypothetical protein FLJ20654 HSAC005138 KIAA0303 AB002301 54985 −0.27897249 KIAA0303 protein KLK7_HUMAN KLK7 NM_005046 151254 −0.27760264 Kallikrein 7 (chymotryptic, stratum corneum) ITP1_HUMAN ICAP-1A NM_004763 173274 0.24572607 Integrin cytoplasmic domain-associated protein 1 CT26_HUMAN C20orf26 AL117439 302122 −0.30839956 Chromosome 20 open reading frame 26 MK06_HUMAN MAPK6 NM_002748 271980 −0.26984777 Mitogen-activated protein kinase 6 HSAC004393 0 AF144233 37372 −0.26241142 Homo sapiens DNA binding peptide mRNA, partial cds UBC3_HUMAN CDC34 NM_004359 76932 0.25377891 Cell division cycle 34 HSAC014234 0 AK056507 183953 −0.24069092 Homo sapiens cDNA FLJ31945 fis, clone NT2RP7006980 BRAF_HUMAN BRAF NM_004333 622 0.23815317 V-raf murine sarcoma viral oncogene homolog B1 HSAC019969 COE2 AK001144 343814 0.23670517 Similar to TRANSCRIPTION FACTOR COE2 (EARLY B-CELL FACTOR 2) (EBF-2) (OLF-1/EBF-LIKE 3) (OE-3) (O/E- HSAC019505 0 AY039026 334395 −0.18416075 Homo sapiens immunoglobulin mu chain antibody MO30 (IgM) mRNA, complete cds EMP1_HUMAN EMP1 NM_001423 79368 −0.30522881 Epithelial membrane protein 1 Q9NRI6 PYY2 NM_021093 157195 −0.28539523 Peptide YY, 2 (seminalplasmin) HSAC008290 MGC5618 BC016015 177781 0.28148678 Hypothetical protein MGC5618 O94927 KIAA0841 AB020648 7426 −0.2681492 KIAA0841 protein PRL1_HUMAN PROL1 NM_021225 87198 −0.26726353 Proline-rich 1 Q9NWQ8 PAG NM_018440 266175 0.26596376 Phosphoprotein associated with glycosphingolipid- enriched microdomains HSAC009739 0 AK021991 296675 0.26376015 Homo sapiens cDNA FLJ11929 fis, clone HEMBB1000434 TAP4_HUMAN TFAP4 NM_003223 3005 −0.24676795 Transcription factor AP-4 (activating enhancer binding protein 4) CSR3_HUMAN CSRP3 NM_003476 83577 0.22957104 Cysteine and glycine- rich protein 3 (cardiac LIM protein) MYH7_HUMAN MYH7 NM_000257 929 0.22417182 Myosin, heavy polypeptide 7, cardiac muscle, beta Q13513 HSU47926 NM_014262 46458 0.2822699 Hypothetical protein B CU97_HUMAN FLJ21324 AL161960 4746 −0.27189524 Hypothetical protein FLJ21324 Q96EL2 MRPS24 NM_032014 284286 0.26906488 Mitochondrial ribosomal protein S24 PYR1_HUMAN CAD NM_004341 154868 0.26618776 Carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase SPS2_HUMAN SPS2 NM_012248 118725 0.23578101 Selenophosphate synthetase 2 HSAC005553 KIAA0483 AB007952 64691 −0.23107771 KIAA0483 protein Q8NC10 FLJ20258 NM_017729 28907 −0.29044408 Hypothetical protein FLJ20258 HSAC007558 0 AK024653 163440 −0.28942837 Homo sapiens cDNA: FLJ21000 fis, clone CAE03359 Q96HT2 0 BC008122 334931 −0.28388928 Homo sapiens , clone MGC: 18053 IMAGE: 4148889, mRNA, complete cds P02570 ACTB NM_001101 288061 0.28095417 Actin, beta Q96HG1 0 BC008642 42239 −0.26271036 Homo sapiens , clone IMAGE: 3868989, mRNA, partial cds Q9H5C5 FLJ23584 NM_024588 22195 −0.25933423 Hypothetical protein FLJ23584 HSAC014930 0 AK022228 202577 −0.25403533 Homo sapiens cDNA FLJ12166 fis, clone MAMMA1000616 Q8ND68 PLVAP NM_031310 107125 0.24973622 Plasmalemma vesicle associated protein Q9NPW0 DKFZp547M236 NM_018713 20981 −0.24604121 Hypothetical protein DKFZp547M236 HSAC001572 0 AK055659 8037 0.24451604 Homo sapiens cDNA FLJ31097 fis, clone IMR321000210 PARB_HUMAN PARVB NM_013327 8836 −0.2429299 Parvin beta HSAC009747 0 AK022065 296683 −0.23257064 Homo sapiens cDNA FLJ12003 fis, clone HEMBB1001537 RL3_HUMAN RPL3 BC011860 119598 0.22612107 Ribosomal protein L3 CA1B_HUMAN COL11A1 NM_001854 82772 0.22373492 Collagen, type XI, alpha 1 STAT_HUMAN STATH NM_003154 37048 −0.18441286 Statherin HSAC015960 0 AF153502 247887 0.27007396 Homo sapiens SNAI1P pseudogene T1L1_HUMAN TOM1L1 NM_005486 153504 −0.25974431 Target of myb1-like 1 (chicken) Q8WV53 DKFZP564A2416 NM_015535 5297 0.25296148 DKFZP564A2416 protein HS9A_HUMAN HSPCA AK056446 289088 0.25051774 Heat shock 90 kD protein 1, alpha BM88_HUMAN BM88 NM_016564 22140 −0.24739798 BM88 antigen HSAC021209 0 AK021479 351685 −0.24183743 Homo sapiens cDNA FLJ11417 fis, clone HEMBA1000960 TIG2_HUMAN RARRES2 NM_002889 37682 0.24052315 Retinoic acid receptor responder (tazarotene induced) 2 ABC3_HUMAN ABCA3 NM_001089 26630 −0.23736913 ATP-binding cassette, sub-family A (ABC1), member 3 Q96SG6 0 BC014899 72087 −0.23557118 Homo sapiens , clone IMAGE: 3912307, mRNA COP1_HUMAN 0 AK056926 350222 0.23440455 Homo sapiens cDNA FLJ32364 fis, clone PUAEN1000147 HSAC005034 0 AF070602 51649 −0.22614962 Homo sapiens clone 24504 mRNA sequence Q9BV20 MGC3207 AK026666 13075 0.21874807 Hypothetical protein MGC3207 IL8_HUMAN IL8 NM_000584 624 0.21295363 Interleukin 8 TGM3_HUMAN TGM3 NM_003245 2022 −0.30559572 Transglutaminase 3 (E polypeptide, protein- glutamine-gamma- glutamyltransferase) FILA_HUMAN 0 BE551792 251440 −0.2882993 EST, Highly similar to A48118 major epidermal calcium- binding protein profilaggrin [ H. sapiens ] Q96DP9 0 AK055428 351007 −0.28316024 Homo sapiens cDNA FLJ30866 fis, clone FEBRA2004110, highly similar to PHOSPHOLIPASE ADRAB-B PRECURSO Q9C0G8 KIAA1695 AB051482 288841 0.27341074 Hypothetical protein FLJ22297 PPIG_HUMAN PPIG NM_004792 77965 −0.26853004 Peptidyl-prolyl isomerase G (cyclophilin G) ANX1_HUMAN ANXA1 NM_000700 78225 −0.26467494 Annexin A1 Q9H8H3 DKFZP586A0522 NM_014033 288771 −0.26179709 DKFZP586A0522 protein ENOA_HUMAN ENO1 NM_001428 254105 0.25723939 Enolase 1, (alpha) SOX5_HUMAN SOX5 NM_006940 87224 −0.25633005 SRY (sex determining region Y)-box 5 MSX1_HUMAN MSX1 NM_002448 1494 0.2563254 Msh homeo box homolog 1 ( Drosophila ) HSAC019559 0 AK021983 334535 −0.25479699 Homo sapiens cDNA FLJ11921 fis, clone HEMBB1000318 HSAC016142 0 X76785 249131 0.24660385 H. sapiens genomic DNA, integration site for Epstein-Barr virus Q9HBZ7 FLJ11305 AK024478 7049 0.24408926 Hypothetical protein FLJ11305 CMST_HUMAN SLC35A1 NM_006416 82921 −0.23742472 Solute carrier family 35 (CMP-sialic acid transporter), member 1 SIM1_HUMAN SIM1 NM_005068 105925 −0.23141341 Single-minded homolog 1 ( Drosophila ) Q8IXU2 FLJ20190 NM_017705 257511 0.21886983 Hypothetical protein FLJ20190 C166_HUMAN ALCAM Y10183 10247 0.19097406 Activated leucocyte cell adhesion molecule Q96AP0 24432 NM_022914 78019 0.1866136 Hypothetical protein 24432 HSAC018926 0 AK000989 319540 −0.1726173 Homo sapiens cDNA FLJ10127 fis, clone HEMBA1002973, moderately similar to CAMP-DEPENDENT 3′,5′-CYCLI HSAC019510 H2AFKP Z80777 334456 −0.2885027 H2A histone family, member K, pseudogene HSAC021283 0 BC018033 351860 −0.27842193 Homo sapiens , clone IMAGE: 4800052, mRNA, partial cds Q9NQ25 CRACC AB027233 132906 −0.25159742 19A24 protein MGP_HUMAN MGP NM_000900 279009 0.25075401 Matrix Gla protein HSAC018514 0 AK024924 306729 −0.24315744 Homo sapiens cDNA: FLJ21271 fis, clone COL01751 ABC6_HUMAN ABCB6 NM_005689 107911 0.24312557 ATP-binding cassette, sub-family B (MDR/TAP), member 6 HSAC016919 HEP27 NM_005794 272499 0.23808329 Short-chain alcohol dehydrogenase family member CD45_HUMAN PTPRC NM_002838 170121 −0.23455219 Protein tyrosine phosphatase, receptor type, C Q9ULT2 KIAA1138 AB032964 115726 −0.22789488 KIAA1138 protein SY3L_HUMAN SCYA3 NM_002983 73817 0.22252932 Small inducible cytokine A3 MM26_HUMAN MMP26 NM_021801 204732 0.18951291 Matrix metalloproteinase 26 PRL4_HUMAN PROL4 NM_007244 45033 −0.01191859 Proline rich 4 (lacrimal) P78545 ELF3 NM_004433 166096 −0.29828398 E74-like factor 3 (ets domain transcription factor, epithelial- specific) NIC1_HUMAN NICE-1 NM_019060 110196 −0.2971944 NICE-1 protein CLD7_HUMAN CLDN7 NM_001307 278562 −0.28206037 Claudin 7 KLKA_HUMAN 0 AK026045 275464 −0.28180039 Homo sapiens cDNA: FLJ22392 fis, clone HRC07868 Q9P0A7 C20orf30 NM_014145 3576 0.27874372 Chromosome 20 open reading frame 30 HSAC019283 0 AK026112 330418 −0.27010085 Homo sapiens cDNA: FLJ22459 fis, clone HRC10045 Q9NYJ6 LOC51328 NM_016637 272413 −0.2695095 Ncaml Q96HJ4 NUF2R NM_031423 234545 −0.2663022 Hypothetical protein NUF2R PAB4_HUMAN PABPC4 NM_003819 169900 0.25652471 Poly(A) binding protein, cytoplasmic 4 (inducible form) HSAC012638 FLJ12994 NM_022841 126908 −0.25215608 Hypothetical protein FLJ12994 HS47_HUMAN SERPINH2 NM_001235 9930 0.2460832 Serine (or cysteine) proteinase inhibitor, clade H (heat shock protein 47), member 2 Q9ULL9 KIAA1201 AB033027 251278 −0.24435799 KIAA1201 protein TYY1_HUMAN YY1 NM_003403 97496 0.23844943 YY1 transcription factor HSAC016540 ENPP3 NM_005021 264750 0.23341437 Ectonucleotide pyrophosphatase/phosphodiesterase 3 IP3K_HUMAN ITPKA NM_002220 2722 0.231694 Inositol 1,4,5- trisphosphate 3-kinase A HSAC009930 MGC17528 BC010541 300893 −0.23039734 Hypothetical protein MGC17528 CRE3_HUMAN CREB3 NM_006368 287921 0.22584512 CAMP responsive element binding protein 3 (luman) HSAC016682 0 AK057367 270002 −0.22515872 Homo sapiens cDNA FLJ32805 fis, clone TESTI2002690 TFE2_HUMAN TCF3 M31523 101047 0.21777199 Transcription factor 3 (E2A immunoglobulin enhancer binding factors E12/E47) BIN1_HUMAN BIN1 NM_004305 193163 0.2155171 Bridging integrator 1 HSAC012959 0 AK023520 131798 −0.21368949 Homo sapiens cDNA FLJ13458 fis, clone PLACE1003361 Q64320 STXBP1 NM_003165 239356 −0.19357344 Syntaxin binding protein 1 3BH1_HUMAN HSD3B1 NM_000862 38586 −0.19079495 Hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta- isomerase 1 P04270 ACTA1 NM_001100 1288 0.17079596 Actin, alpha 1, skeletal muscle GLPB_HUMAN GYPA NM_002099 108694 −0.2797532 Glycophorin A (includes MN blood group) TIG3_HUMAN RARRES3 NM_004585 17466 −0.26355336 Retinoic acid receptor responder (tazarotene induced) 3 Q9HAE0 FLJ11783 NM_024891 232167 −0.26191261 Hypothetical protein FLJ11783 OFU1_HUMAN POFUT1 AF375884 178292 0.25365544 Protein O- fucosyltransferase 1 HSAC009500 MMPL1 NM_004142 290222 −0.25346089 Matrix metalloproteinase-like 1 COXK_HUMAN COX7A1 NM_001864 114346 0.25190367 Cytochrome c oxidase subunit VIIa polypeptide 1 (muscle) BTE1_HUMAN BTEB1 NM_001206 150557 0.24546012 Basic transcription element binding protein OPSD_HUMAN RHO NM_000539 247565 0.24293319 Rhodopsin (opsin 2, rod pigment) (retinitis pigmentosa 4, autosomal dominant) PLCB_HUMAN AGPAT2 NM_006412 209119 0.24123053 1-acylglycerol-3- phosphate O- acyltransferase 2 (lysophosphatidic acid acyltransferase, beta) Q15668 NPC2 NM_006432 119529 0.22752332 Niemann-Pick disease, type C2 Q9UBI4 STOML1 NM_004809 194816 0.21956228 Stomatin (EBP72)-like 1 AAP04413 0 AL133654 201603 0.21881691 Homo sapiens mRNA; cDNA DKFZp434D0917 (from clone DKFZp434D0917) Q8WWF8 0 BC017586 55150 −0.19756688 Homo sapiens , Similar to RIKEN cDNA 1700028N11 gene, clone MGC: 26610 IMAGE: 4837506, mRNA, complete c HSAC018492 0 AK024800 306704 −0.28750526 Homo sapiens cDNA: FLJ21147 fis, clone CAS09371 Q9C0D8 0 BC008941 207024 −0.28684225 Homo sapiens , Similar to hypothetical protein FLJ20515, clone MGC: 2696 IMAGE: 2820596, mRNA, complete DDC_HUMAN DDC NM_000790 150403 −0.2843375 Dopa decarboxylase (aromatic L-amino acid decarboxylase) FBW4_HUMAN SHFM3 AK056917 24307 0.28026937 Split hand/foot malformation (ectrodactyly) type 3 QCAA000051 0 0 0 −0.26836294 Randomized negative control Q9UM77 OR1E3P U53583 248182 −0.2620377 Olfactory receptor, family 1, subfamily E, member 3 pseudogene TYBP_HUMAN TYROBP NM_003332 9963 −0.25688511 TYRO protein tyrosine kinase binding protein SCP1_HUMAN SYCP1 NM_003176 112743 −0.25216102 Synaptonemal complex protein 1 Q9HCH7 KIAA1595 AB046815 286173 0.25125685 KIAA1595 protein HSAC012142 ERH NM_004450 118757 0.24637661 Enhancer of rudimentary homolog ( Drosophila ) ACLY_HUMAN ACLY NM_001096 174140 0.24619185 ATP citrate lyase S3B2_HUMAN SF3B2 NM_006842 75916 0.24414637 Splicing factor 3b, subunit 2, 145 kD O14731 PKMYT1 NM_004203 77783 0.24202938 Membrane-associated tyrosine- and threonine-specific cdc2-inhibitory kinase HSAC003854 0 AK025794 28631 −0.24081021 Homo sapiens cDNA: FLJ22141 fis, clone HEP21327 HSAC020709 0 AK057203 350710 −0.23982763 Homo sapiens cDNA FLJ32641 fis, clone SYNOV2001035 UNRI_HUMAN UNRIP NM_007178 3727 0.23894091 Unr-interacting protein PGTA_HUMAN RABGGTA NM_004581 78920 −0.23645356 Rab geranylgeranyltransferase, alpha subunit HSAC019191 0 AL080233 326580 −0.23022427 Homo sapiens mRNA; cDNA DKFZp586L111 (from clone DKFZp586L111) SDB2_HUMAN SDCBP2 NM_015685 64179 −0.22859025 Syndecan binding protein (syntenin) 2 CTC9_HUMAN C20orf129 AK055793 70704 −0.22775703 Chromosome 20 open reading frame 129 PCN2_HUMAN PCNT2 NM_006031 15896 −0.22667113 Pericentrin 2 (kendrin) IF42_HUMAN EIF4A2 NM_001967 173912 0.22657769 Eukaryotic translation initiation factor 4A, isoform 2 HSAC018456 0 AK024123 306664 −0.22504349 Homo sapiens cDNA FLJ14061 fis, clone HEMBB1000749 HSAC018632 0 AK026722 306870 0.22009923 Homo sapiens cDNA: FLJ23069 fis, clone LNG05603 ATS1_HUMAN ADAMTS1 NM_006988 8230 0.20713748 A disintegrin-like and metalloprotease (reprolysin type) with thrombospondin type 1 motif, 1 Q96DP3 WAC AB058747 70333 0.20422375 WW domain-containing adapter with a coiled- coil region HSAC002790 DKFZp667O2416 AK056427 19066 −0.19264477 Hypothetical protein DKFZp667O2416 AN11_HUMAN ANAPC11 NM_016476 183180 0.18856896 APC11 anaphase promoting complex subunit 11 homolog (yeast) Q96M94 KIAA1677 AB051464 61603 0.17363087 KIAA1677 HSAC017386 HSPC073 NM_014163 278948 0.15730714 HSPC073 protein HSAC006154 CD14 NM_000591 75627 0.27102209 CD14 antigen PPIF_HUMAN PPIF NM_005729 173125 −0.26443857 Peptidylprolyl isomerase F (cyclophilin F) Q9NT21 0 AL137581 112589 −0.26076922 Homo sapiens mRNA; cDNA DKFZp434B0610 (from clone DKFZp434B0610); partial cds Q9H6B9 FLJ22408 NM_024794 156457 −0.25752275 Hypothetical protein FLJ22408 LDHA_HUMAN LDHA NM_005566 2795 0.25289918 Lactate dehydrogenase A H2AY_HUMAN H2AFY NM_004893 75258 −0.2518442 H2A histone family, member Y HSAC009983 0 AK022320 301232 −0.2470859 Homo sapiens cDNA FLJ12258 fis, clone MAMMA1001510 HSAC014390 0 AK001865 188228 0.24557304 Homo sapiens cDNA FLJ11003 fis, clone PLACE1002851 GT4R_HUMAN SLC2A4RG NM_020062 170088 0.24473836 SLC2A4 regulator FOS_HUMAN FOS NM_005252 25647 −0.24335376 V-fos FBJ murine osteosarcoma viral oncogene homolog Q9BWL3 DKFZP586G1722 NM_015449 31989 0.24290984 DKFZP586G1722 protein CY1_HUMAN CYC1 NM_001916 289271 0.242676 Cytochrome c-1 Q8IX90 0 BC013418 88523 0.24027868 Homo sapiens , clone MGC: 4832 IMAGE: 3604003, mRNA, complete cds GALA_HUMAN GAL M77140 1907 0.23487288 Galanin P02593 CALM2 AK055130 182278 0.23450179 Calmodulin 2 (phosphorylase kinase, delta) HSAC020657 0 AK057533 350657 0.2332272 Homo sapiens cDNA FLJ32971 fis, clone TESTI2008847 Q9H125 C20orf118 AL079335 287784 0.22896758 Chromosome 20 open reading frame 118 Q8N8N8 DKFZP434G145 BC007359 31931 0.22106691 DKFZP434G145 protein GBAP_HUMAN GABARAP NM_007278 7719 −0.22052485 GABA(A) receptor- associated protein DYI4_HUMAN DNAI2 NM_023036 147472 0.2163783 Dynein intermediate chain 2 HSAC017486 HDAC3 AF130111 279789 −0.21279266 Histone deacetylase 3 NUBM_HUMAN 0 AK055875 324151 0.21264326 Homo sapiens cDNA FLJ31313 fis, clone LIVER1000230, highly similar to NADH- UBIQUINONE OXIDOREDUCTASE NRCA_HUMAN NRCAM NM_005010 7912 −0.20902953 Neuronal cell adhesion molecule IF42_HUMAN EIF4A2 NM_001967 173912 0.20860474 Eukaryotic translation initiation factor 4A, isoform 2 CATB_HUMAN CTSB NM_001908 297939 0.20693544 Cathepsin B HSAC009142 0 AK026499 287713 −0.20623884 Homo sapiens cDNA: FLJ22752 fis, clone KAIA0555 NGAP_HUMAN RASAL2 NM_004841 227806 0.18773486 RAS protein activator like 2 H10_HUMAN H1F0 BC000145 226117 0.18021445 H1 histone family, member 0 RNP_HUMAN RNASE1 NM_002933 78224 0.17681221 Ribonuclease, RNase A family, 1 (pancreatic) HSAC021160 0 AK054984 351562 0.13703193 Homo sapiens cDNA FLJ30422 fis, clone BRACE2008861 Q9BYE3 LEP16 NM_032563 244349 −0.28446955 Epidermal differentiation complex protein like protein O75042 0 AK024906 160613 −0.26547427 Homo sapiens cDNA: FLJ21253 fis, clone COL01316 HSAC017211 0 AK021887 277001 −0.26476404 Homo sapiens cDNA FLJ11825 fis, clone HEMBA1006494 IDI1_HUMAN IDI1 NM_004508 76038 −0.25999498 Isopentenyl- diphosphate delta isomerase HSAC006238 TMSB4X AK055976 75968 0.25632509 Thymosin, beta 4, X chromosome ETS2_HUMAN ETS2 NM_005239 85146 −0.2516845 V-ets erythroblastosis virus E26 oncogene homolog 2 (avian) SSB4_HUMAN MGC3181 NM_032627 324618 0.24973691 Hypothetical protein MGC3181 O60426 FADS3 NM_021727 21765 0.24927285 Fatty acid desaturase 3 LDHA_HUMAN LDHA NM_005566 2795 0.24753928 Lactate dehydrogenase A KB15_HUMAN KIAA1115 NM_014931 72172 −0.24331719 KIAA1115 protein HSAC014795 PLSCR1 NM_021105 198282 −0.24294281 Phospholipid scramblase 1 CO1A_HUMAN CORO1A NM_007074 109606 −0.24222576 Coronin, actin binding protein, 1A K1CP_HUMAN KRT16 NM_005557 115947 −0.23828098 Keratin 16 (focal non- epidermolytic palmoplantar keratoderma) CT11_HUMAN C20orf11 NM_017896 103808 0.23722689 Chromosome 20 open reading frame 11 HSAC016239 0 AL049369 250724 −0.23637937 Homo sapiens mRNA; cDNA DKFZp586D0518 (from clone DKFZp586D0518) LDHA_HUMAN LDHA NM_005566 2795 0.23548608 Lactate dehydrogenase A ST24_HUMAN STK24 NM_003576 168913 −0.23478567 Serine/threonine kinase 24 (STE20 homolog, yeast) O60527 SDCCAG8 AF039690 300642 −0.23195532 Serologically defined colon cancer antigen 8 HSAC018030 0 AL049275 302051 −0.23020458 Homo sapiens mRNA; cDNA DKFZp564H213 (from clone DKFZp564H213) HSAC018565 0 AK025194 306784 0.22999594 Homo sapiens cDNA: FLJ21541 fis, clone COL06166 PO43_HUMAN POU4F3 NM_002700 248019 −0.22881509 POU domain, class 4, transcription factor 3 HSAC015174 0 AC006328 213956 0.22863598 Homo sapiens BAC clone RP11-102O5 from Y Q9H0N3 DKFZP566M1046 NM_032127 8039 0.22863435 Hypothetical protein DKFZp566M1046 7B2_HUMAN SGNE1 NM_003020 2265 −0.22641912 Secretory granule, neuroendocrine protein 1 (7B2 protein) IP3S_HUMAN ITPR2 NM_002223 238272 −0.2261709 Inositol 1,4,5- triphosphate receptor, type 2 Q9UEF2 UBC M26880 183704 −0.22356958 Ubiquitin C HSAC018590 0 AK025451 306812 −0.22302005 Homo sapiens cDNA: FLJ21798 fis, clone HEP00573 Q8WY82 0 BC006284 333388 −0.22271485 Homo sapiens , clone IMAGE: 3957135, mRNA, partial cds TSP4_HUMAN THBS4 NM_003248 75774 0.22139735 Thrombospondin 4 HSAC002075 LOC51170 NM_016245 12150 0.22091464 Retinal short-chain dehydrogenase/reductase retSDR2 HSAC009969 0 AK021935 301153 0.21899011 Homo sapiens cDNA FLJ11873 fis, clone HEMBA1007066 HSAC007149 0 AL080078 85335 −0.21515156 Homo sapiens mRNA; cDNA DKFZp564D1462 (from clone DKFZp564D1462) MK01_HUMAN MAPK1 AL157438 324473 0.21202447 Mitogen-activated protein kinase 1 9KD_HUMAN MGC10471 NM_030818 24998 −0.21138421 Hypothetical protein MGC10471 HSAC018712 KAP4.14 NM_033059 307015 −0.21048412 Keratin associated protein 4.14 TYPH_HUMAN ECGF1 NM_001953 73946 −0.20356611 Endothelial cell growth factor 1 (platelet- derived) Q9UBF4 KIAA1036 NM_014909 155182 0.20323707 KIAA1036 protein CIQ5_HUMAN KCNQ5 NM_019842 283644 0.20086104 Potassium voltage- gated channel, KQT- like subfamily, member 5 P39028 RPS23 NM_001025 3463 0.19967718 Ribosomal protein S23 NF3L_HUMAN NIF3L1 NM_021824 21943 −0.18719016 NIF3 NGG1 interacting factor 3-like 1 ( S. pombe ) GTO1_HUMAN GSTTLp28 NM_004832 11465 0.17999128 Glutathione-S- transferase like; glutathione transferase omega RAC2_HUMAN HSPC022 NM_014029 301175 0.17873117 HSPC022 protein Q9HAC8 FLJ11807 NM_024954 285813 0.17686817 Hypothetical protein FLJ11807 RALA_HUMAN 0 AK026850 6906 0.17343054 Homo sapiens cDNA: FLJ23197 fis, clone REC00917 CSR2_HUMAN CSRP2 NM_001321 10526 0.17334591 Cysteine and glycine- rich protein 2 HSAC019311 0 BC005220 332008 −0.17218654 Homo sapiens , Similar to chaperonin containing TCP1, subunit 8 (theta), clone MGC: 12240 IMAGE: 393033 MNK2_HUMAN GPRK7 NM_017572 261828 −0.16694331 G protein-coupled receptor kinase 7 HSAC014448 FLJ13385 NM_024853 190279 −0.16552904 Hypothetical protein FLJ13385 143F_HUMAN YWHAH NM_003405 349530 0.14759809 Tyrosine 3- monooxygenase/tryptophan 5- monooxygenase activation protein, eta polypeptide Q96MZ7 0 AK056203 323813 0.1170698 Homo sapiens , clone MGC: 2867 IMAGE: 2988664, mRNA, complete cds LOXR_HUMAN ALOX12B NM_001139 136574 −0.33086759 Arachidonate 12- lipoxygenase, 12R type BD02_HUMAN DEFB2 NM_004942 105924 −0.30510738 Defensin, beta 2 HSAC016948 FLJ20433 NM_017820 272799 −0.29024904 Hypothetical protein FLJ20433 S112_HUMAN S100A12 NM_005621 19413 −0.28725669 S100 calcium binding protein A12 (calgranulin C) HSAC018084 0 AF130062 302146 −0.25929293 Homo sapiens clone FLB7715 PRO2051 mRNA, complete cds Q9NPA8 DC6 NM_020189 283740 0.25384995 DC6 protein HSAC004275 0 AK001638 34790 −0.24604722 Homo sapiens cDNA FLJ10776 fis, clone NT2RP4000323 HSAC018560 0 AK025177 306778 −0.24446302 Homo sapiens cDNA: FLJ21524 fis, clone COL05921 HSAC020812 0 AK055957 350815 −0.24373933 Homo sapiens cDNA FLJ31395 fis, clone NT2NE1000122 HSAC018421 0 AK022022 306620 −0.24043929 Homo sapiens cDNA FLJ11960 fis, clone HEMBB1001008 O95204 MP1 NM_014889 260116 −0.23934663 Metalloprotease 1 (pitrilysin family) Q96IC1 AGRN AF016903 273330 0.23808476 Agrin AKBA_HUMAN AKR1B10 NM_020299 116724 −0.23802389 Aldo-keto reductase family 1, member B10 (aldose reductase) LDHA_HUMAN LDHA NM_005566 2795 0.23795266 Lactate dehydrogenase A PTK6_HUMAN PTK6 NM_005975 51133 −0.23581278 PTK6 protein tyrosine kinase 6 NUOM_HUMAN NDUFV3 NM_021075 351217 −0.23366493 NADH dehydrogenase (ubiquinone) flavoprotein 3 (10 kD) GBP2_HUMAN GBP2 NM_004120 171862 −0.23313126 Guanylate binding protein 2, interferon- inducible Q9Y2I3 KIAA0977 NM_014900 300855 −0.23204872 KIAA0977 protein ATS2_HUMAN ADAMTS2 NM_014244 120330 0.2317392 A disintegrin-like and metalloprotease (reprolysin type) with thrombospondin type 1 motif, 2 Q9P1G3 PRO1853 NM_018607 52891 −0.23061723 Hypothetical protein PRO1853 Q92616 GCN1L1 D86973 75354 0.22882625 GCN1 general control of amino-acid synthesis 1-like 1 (yeast) SLI1_HUMAN FHL1 NM_001449 239069 0.22601495 Four and a half LIM domains 1 HSAC010091 R33729_1 Z78330 10927 −0.22537096 Hypothetical protein R33729_1 S6AC_HUMAN SLC6A12 U27699 82535 −0.22507903 Solute carrier family 6 (neurotransmitter transporter, betaine/GABA), member 12 Y110_HUMAN KIAA0110 NM_014628 124 0.22461245 Gene predicted from cDNA with a complete coding sequence HSAC013952 SP3 X68560 154295 −0.22445276 Sp3 transcription factor SYD_HUMAN DARS NM_001349 80758 0.22434629 Aspartyl-tRNA synthetase RL7_HUMAN RPL7 NM_000971 153 0.22410736 Ribosomal protein L7 SNK_HUMAN SNK NM_006622 3838 −0.22350301 Serum-inducible kinase ID3_HUMAN ID3 NM_002167 76884 −0.22236535 Inhibitor of DNA binding 3, dominant negative helix-loop- helix protein RMP1_HUMAN RAMP1 NM_005855 32989 0.22176553 Receptor (calcitonin) activity modifying protein 1 FK26_HUMAN KIAA1049 NM_014972 227835 0.22124994 KIAA1049 protein IEX1_HUMAN IER3 NM_052815 76095 0.22091401 Immediate early response 3 PTPK_HUMAN PTPRK NM_002844 79005 0.22006385 Protein tyrosine phosphatase, receptor type, K HPS4_HUMAN 0 AK057648 350640 0.21953415 Homo sapiens cDNA FLJ33086 fis, clone TRACH2000461 LDHB_HUMAN LDHB BC008952 234489 0.21684934 Lactate dehydrogenase B Q8NDB6 PRO0659 AK054721 6451 0.21637177 PRO0659 protein N7BM_HUMAN DAP13 NM_018838 44163 −0.21579024 13 kDa differentiation- associated protein Q9H7Z7 C9orf15 NM_025072 288102 −0.21525058 Chromosome 9 open reading frame 15 TM22_HUMAN TRIM22 NM_006074 318501 −0.21520167 Tripartite motif- containing 22 Q9H749 DKFZP586D0919 AL050100 49378 0.21169944 DKFZP586D0919 protein Q969K7 CAC-1 NM_033504 343912 −0.21091675 CAC-1 OAS3_HUMAN OAS3 NM_006187 56009 −0.20966638 2′-5′-oligoadenylate synthetase 3 (100 kD) PAN2_HUMAN PANX2 NM_052839 343259 0.20929628 Pannexin 2 IFT1_HUMAN IFIT1 NM_001548 20315 −0.20924493 Interferon-induced protein with tetratricopeptide repeats 1 Q96HK5 LOC51030 NM_016078 6776 −0.20809385 CGI-148 protein DDX3_HUMAN DDX3 NM_001356 147916 −0.20803591 DEAD/H (Asp-Glu-Ala- Asp/His) box polypeptide 3 IF42_HUMAN EIF4A2 NM_001967 173912 0.20756638 Eukaryotic translation initiation factor 4A, isoform 2 Q9NPI0 0 AK027724 334557 −0.20655815 Homo sapiens cDNA FLJ14818 fis, clone OVARC1000168 P11082 PPP2CB NM_004156 80350 −0.20633072 Protein phosphatase 2 (formerly 2A), catalytic subunit, beta isoform HSAC004729 0 AK021604 44787 −0.20569729 Homo sapiens mRNA; cDNA DKFZp434O0227 (from clone DKFZp434O0227) THTR_HUMAN TST NM_003312 351863 −0.20339936 Thiosulfate sulfurtransferase (rhodanese) APL1_HUMAN APOL1 AF323540 114309 −0.2014645 Apolipoprotein L, 1 Q96IP9 H41 AF103803 283690 −0.19892848 Hypothetical protein PSB5_HUMAN PSMB5 NM_002797 78596 0.19884452 Proteasome (prosome, macropain) subunit, beta type, 5 Q96MH6 0 AK056932 280858 −0.19855951 Homo sapiens cDNA FLJ32370 fis, clone PUAEN1000322 Q96DR8 LOC118430 NM_058173 348419 −0.19728271 Small breast epithelial mucin HSAC020134 0 BG912466 347715 −0.19659403 Homo sapiens mRNA full length insert cDNA clone EUROIMAGE 152428 APA1_HUMAN APOA1 NM_000039 93194 0.19456431 Apolipoprotein A-I IKBA_HUMAN NFKBIA NM_020529 81328 0.19434039 Nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor, alpha S61G_HUMAN SEC61G NM_014302 9950 0.19385443 Sec61 gamma Q8TB66 NIFK NM_032390 142838 0.19235852 Nucleolar protein interacting with the FHA domain of pKi-67 FXLA_HUMAN PCCX2 AB031230 199009 −0.19227016 Protein containing CXXC domain 2 HSAC005389 PRO2086 NM_014111 60082 −0.19183233 PRO2086 protein TGDS_HUMAN TDPGD NM_014305 12393 0.19120788 DTDP-D-glucose 4,6- dehydratase Q9NYL1 PTOV1 NM_017432 19555 0.18942731 Prostate tumor over expressed gene 1 RET7_HUMAN RBP7 NM_052960 292718 0.18902609 Retinoid binding protein 7 Q9H5V9 FLJ22965 NM_022101 248572 0.18655842 Hypothetical protein FLJ22965 O94911 ABCA8 NM_007168 38095 −0.18602829 ATP-binding cassette, sub-family A (ABC1), member 8 AAH50307 MORC NM_014429 278908 −0.18567819 Microrchidia homolog (mouse) TR1B_HUMAN TNFRSF1B NM_001066 256278 0.18560882 Tumor necrosis factor receptor superfamily, member 1B HS71_HUMAN HSPA1A NM_005345 8997 0.18329446 Heat shock 70 kD protein 1A Q9C086 PAPA-1 NM_031288 118282 −0.18173371 PAP-1 binding protein HSAC005625 0 AL050367 66762 0.17583034 Homo sapiens mRNA; cDNA DKFZp564A026 (from clone DKFZp564A026) HSAC000871 0 AK024270 4094 0.17415618 Homo sapiens cDNA FLJ14208 fis, clone NT2RP3003264 Q9H655 FLJ22595 NM_025047 287702 −0.17240792 Hypothetical protein FLJ22595 HSAC018574 0 AK025291 306794 −0.16937687 Homo sapiens cDNA: FLJ21638 fis, clone COL08269 Q9UK76 HN1 NM_016185 109706 0.16129563 Hematological and neurological expressed 1 INI2_HUMAN G1P3 NM_022873 265827 −0.15984033 Interferon, alpha- inducible protein (clone IFI-6-16) HRG_HUMAN HRG NM_000412 1498 0.15777333 Histidine-rich glycoprotein Q9ULD2 ATIP1 AB033114 7946 −0.15367977 AT2 receptor- interacting protein 1 TRBM_HUMAN THBD NM_000361 2030 −0.1417714 Thrombomodulin HSAC015082 0 AK023326 210844 −0.13617964 Homo sapiens cDNA FLJ13264 fis, clone OVARC1000936, weakly similar to COAT PROTEIN GP37 HSAC002372 0 AK023269 14355 0.13539305 Homo sapiens cDNA FLJ13207 fis, clone NT2RP4000023 ITB4_HUMAN ITGB4 NM_000213 85266 0.12885959 Integrin, beta 4 HSAC013491 0 AL157491 145211 −0.11058947 Homo sapiens mRNA; cDNA DKFZp434K1111 (from clone DKFZp434K1111) Q8TAD5 SPANXB1 NM_032461 293266 0.08476128 SPANX family, member B1 Q96SV0 FLJ14621 NM_032811 10056 −0.08227502 Hypothetical protein FLJ14621 Q9ULE7 KIAA1273 AB033099 23413 −0.05093065 KIAA1273 protein [0000] TABLE 4 List of 179 genes with strong predictive value N+ UniProt Gene_symbol GB_accession UniGene_ID correlation Gene Q9NZQ6 COL5A3 NM_015719 235368 0.57481098 Collagen, type V, alpha 3 FINC_HUMAN FN1 NM_002026 287820 0.55126846 Fibronectin 1 FSL1_HUMAN FSTL1 NM_007085 296267 0.53452734 Follistatin-like 1 ER22_HUMAN KDELR2 NM_006854 118778 0.52986731 KDEL (Lys-Asp-Glu- Leu) endoplasmic reticulum protein retention receptor 2 PCO1_HUMAN PCOLCE NM_002593 202097 0.52672595 Procollagen C- endopeptidase enhancer SPRC_HUMAN SPARC NM_003118 111779 0.51922531 Secreted protein, acidic, cysteine-rich (osteonectin) NC5R_HUMAN DIA1 NM_007326 274464 0.51482855 Diaphorase (NADH) (cytochrome b-5 reductase) SEPR_HUMAN FAP NM_004460 418 0.51466336 Fibroblast activation protein, alpha HSAC013564 COL5A1 NM_000093 146428 0.51225806 Collagen, type V, alpha 1 HSAC009848 ZFP93 NM_004234 298089 0.50989391 Zinc finger protein 93 homolog (mouse) PGCV_HUMAN CSPG2 U16306 81800 0.50906177 Chondroitin sulfate proteoglycan 2 (versican) Q14521 LLGL2 NM_004524 3123 −0.50695888 Lethal giant larvae homolog 2 ( Drosophila ) CA14_HUMAN COL4A1 NM_001845 119129 0.50664753 Collagen, type IV, alpha 1 HSAC014709 TEM1 NM_020404 195727 0.50647843 Tumor endothelial marker 1 precursor UROK_HUMAN PLAU NM_002658 77274 0.50439834 Plasminogen activator, urokinase Q8N6P7 IL22R NM_021258 110915 −0.49928496 Interleukin 22 receptor LEG1_HUMAN LGALS1 NM_002305 227751 0.48740219 Lectin, galactoside- binding, soluble, 1 (galectin 1) CA25_HUMAN COL5A2 NM_000393 82985 0.48675513 Collagen, type V, alpha 2 CA13_HUMAN COL3A1 NM_000090 119571 0.48459913 Collagen, type III, alpha 1 (Ehlers-Danlos syndrome type IV, autosomal dominant) Q9BYD5 LOC84518 NM_032488 148590 −0.48449285 Protein related with psoriasis BGH3_HUMAN TGFBI NM_000358 118787 0.48290139 Transforming growth factor, beta-induced, 68 kD CQT6_HUMAN CTRP6 NM_031910 22011 0.47978614 Complement-c1q tumor necrosis factor-related protein 6 AD12_HUMAN ADAM12 NM_003474 8850 0.47905457 A disintegrin and metalloproteinase domain 12 (meltrin alpha) Q8N3N2 FLJ11196 NM_018357 6166 0.47772636 Hypothetical protein FLJ11196 CATK_HUMAN CTSK NM_000396 83942 0.47734967 Cathepsin K (pycnodysostosis) Q96DR2 0 AK055031 44289 −0.47659518 Homo sapiens cDNA FLJ30469 fis, clone BRAWH1000037, weakly similar to UROKINASE PLASMINOGEN ACTIVATO P03996 ACTA2 NM_001613 195851 0.47560995 Actin, alpha 2, smooth muscle, aorta K6A2_HUMAN 0 AK027727 184581 0.47396182 Homo sapiens cDNA FLJ14821 fis, clone OVARC1000556, highly similar to RIBOSOMAL PROTEIN S6 KINASE II Q9HBB0 THY1 AK057865 125359 0.4727028 Thy-1 cell surface antigen TM29_HUMAN TRIM29 NM_012101 82237 −0.47250994 Tripartite motif- containing 29 TIM2_HUMAN 0 AL110197 6441 0.47199573 Homo sapiens mRNA; cDNA DKFZp586J021 (from clone DKFZp586J021) MM02_HUMAN MMP2 NM_004530 111301 0.47026319 Matrix metalloproteinase 2 (gelatinase A, 72 kD gelatinase, 72 kD type IV collagenase) MCA2_HUMAN JTV1 NM_006303 301613 0.46964142 JTV1 gene CA16_HUMAN COL6A1 NM_001848 108885 0.46942561 Collagen, type VI, alpha 1 EVA1_HUMAN EVA1 AF275945 116651 −0.4689165 Epithelial V-like antigen 1 CA21_HUMAN COL1A2 NM_000089 179573 0.46739585 Collagen, type I, alpha 2 CA36_HUMAN COL6A3 NM_004369 80988 0.46507048 Collagen, type VI, alpha 3 OPN3_HUMAN OPN3 NM_014322 279926 0.46101056 Opsin 3 (encephalopsin, panopsin) Q9UBG0 KIAA0709 NM_006039 7835 0.46012143 Endocytic receptor (macrophage mannose receptor family) TPM2_HUMAN TPM2 NM_003289 300772 0.46003075 Tropomyosin 2 (beta) INVO_HUMAN IVL NM_005547 157091 −0.45860578 Involucrin O88386 RAB10 NM_016131 236494 −0.45006586 RAB10, member RAS oncogene family PEPL_HUMAN PPL NM_002705 74304 −0.44874989 Periplakin HSAC002603 FLJ11036 NM_018306 16740 −0.44841185 Hypothetical protein FLJ11036 TNR5_HUMAN TNFRSF5 NM_001250 25648 −0.44547341 Tumor necrosis factor receptor superfamily, member 5 FRIH_HUMAN FTH1 AK054816 62954 0.4396982 Ferritin, heavy polypeptide 1 P4H2_HUMAN P4HA2 NM_004199 3622 0.42478412 Procollagen-proline, 2- oxoglutarate 4- dioxygenase (proline 4- hydroxylase), alpha polypeptide II P09526 RAP1B NM_015646 156764 0.42234208 RAP1B, member of RAS oncogene family PS23_HUMAN SPUVE NM_007173 25338 0.42080095 Protease, serine, 23 HSAC011159 0 AF009267 102238 −0.46560322 Homo sapiens clone FBA1 Cri-du-chat region mRNA SDC2_HUMAN SDC2 J04621 1501 0.45455196 Syndecan 2 (heparan sulfate proteoglycan 1, cell surface-associated, fibroglycan) HSAC013320 0 AL162069 140978 −0.44362782 Homo sapiens mRNA; cDNA DKFZp762H106 (from clone DKFZp762H106) TAGL_HUMAN TAGLN NM_003186 75777 0.4376112 Transgelin MM01_HUMAN MMP1 NM_002421 83169 0.4326825 Matrix metalloproteinase 1 (interstitial collagenase) P05209 K-ALPHA-1 NM_006082 334842 0.42236541 Tubulin, alpha, ubiquitous TSP2_HUMAN THBS2 NM_003247 108623 0.46791583 Thrombospondin 2 Q8N789 DKFZP4 AL137589 152149 −0.43787021 Hypothetical protein 34K0410 DKFZp434K0410 O60335 KIAA0594 AB011166 103283 −0.42578156 KIAA0594 protein P05209 K-ALPHA-1 NM_006082 334842 0.42277793 Tubulin, alpha, ubiquitous TNI3_HUMAN TNFAIP3 NM_006290 211600 0.408128 Tumor necrosis factor, alpha-induced protein 3 FGR1_HUMAN FGFR1 NM_023109 748 0.43553561 Fibroblast growth factor receptor 1 (fms-related tyrosine kinase 2, Pfeiffer syndrome) CAD2_HUMAN CDH2 NM_001792 161 0.3922152 Cadherin 2, type 1, N- cadherin (neuronal) TCOF_HUMAN TCOF1 NM_000356 301266 0.38956707 Treacher Collins- Franceschetti syndrome 1 O14635 0 AF005082 113261 −0.45637623 Homo sapiens skin- specific protein (xp33) mRNA, partial cds GLSK_HUMAN GLS NM_014905 239189 0.43214995 Glutaminase Q9BRJ6 MGC11257 NM_032350 334368 0.42954566 Hypothetical protein MGC11257 ALK1_HUMAN SLPI NM_003064 251754 −0.41872706 Secretory leukocyte protease inhibitor (antileukoproteinase) AQP3_HUMAN AQP3 NM_004925 234642 −0.42891866 Aquaporin 3 SPIB_HUMAN SPIB NM_003121 192861 −0.41021146 Spi-B transcription factor (Spi-1/PU.1 related) P05209 K-ALPHA-1 NM_006082 334842 0.41796901 Tubulin, alpha, ubiquitous DRG1_HUMAN DRG1 NM_004147 115242 0.41879372 Developmentally regulated GTP binding protein 1 PHMX_HUMAN PHEMX NM_005705 271954 0.38728757 Pan-hematopoietic expression P05209 K-ALPHA-1 NM_006082 334842 0.41741385 Tubulin, alpha, ubiquitous HSAC018335 0 AL137428 306459 −0.45404252 Homo sapiens mRNA; cDNA DKFZp761N1323 (from clone DKFZp761N1323) POSN_HUMAN OSF-2 NM_006475 136348 0.42814786 Osteoblast specific factor 2 (fasciclin I-like) DHC3_HUMAN CBR3 NM_001236 154510 −0.48089013 Carbonyl reductase 3 NCR2_HUMAN NCOR2 NM_006312 287994 0.42024512 Nuclear receptor co- repressor 2 HSAC015262 0 AK021531 224398 0.43632187 Homo sapiens cDNA FLJ11469 fis, clone HEMBA1001658 Q14113 AEBP1 NM_001129 118397 0.42087649 AE binding protein 1 TBX2_HUMAN TBX2 AK001031 322856 0.41381789 T-box 2 CRF_HUMAN CRH NM_000756 75294 −0.41353804 Corticotropin releasing hormone Q9NUJ7 FLJ11323 NM_018390 25625 −0.43842923 Hypothetical protein FLJ11323 Q96DU1 AKAP2 AJ303079 42322 −0.44106809 A kinase (PRKA) anchor protein 2 P05209 K-ALPHA-1 NM_006082 334842 0.40736744 Tubulin, alpha, ubiquitous Q969Y7 MGC4677 NM_052871 337986 0.39455354 Hypothetical protein MGC4677 Q9BXY6 FLJ13962 NM_024862 330407 −0.44327759 Hypothetical protein FLJ13962 K1CW_HUMAN HAIK1 NM_015515 9029 −0.42594883 Type I intermediate filament cytokeratin HSAC019114 FLJ22622 NM_025151 324841 −0.4331912 Hypothetical protein FLJ22622 PGS2_HUMAN DCN NM_001920 76152 0.39882715 Decorin DCOP_HUMAN ODC-p NM_052998 91681 −0.41609162 Ornithine decarboxylase-like protein HSAC020747 0 AK056828 350748 −0.40822563 Homo sapiens cDNA FLJ32266 fis, clone PROST1000419 P05209 K-ALPHA-1 NM_006082 334842 0.39997295 Tubulin, alpha, ubiquitous Q96F00 0 AK025719 251664 0.39457176 Homo sapiens cDNA: FLJ22066 fis, clone HEP10611 ISK5_HUMAN SPINK5 NM_006846 331555 −0.43770884 Serine protease inhibitor, Kazal type, 5 GFR1_HUMAN GFRA1 NM_005264 105445 0.37859516 GDNF family receptor alpha 1 AAF24516 NUDEL NM_030808 3850 −0.40726277 LIS1-interacting protein NUDEL; endooligopeptidase A P05209 K-ALPHA-1 NM_006082 334842 0.39594293 Tubulin, alpha, ubiquitous O60836 T1A-2 NM_013317 135150 0.37127534 Lung type-I cell membrane-associated glycoprotein KLKA_HUMAN KLK10 NM_002776 69423 −0.40584943 Kallikrein 10 Q96KC3 MGC3047 NM_032348 59384 0.39922401 Hypothetical protein MGC3047 O95274 C4.4A NM_014400 11950 −0.39942513 GPI-anchored metastasis-associated protein homolog HSAC015726 SERPINB13 AJ001696 241407 −0.41273549 Serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 13 SEN7_HUMAN SENP7 AL136599 30443 −0.37916215 Sentrin/SUMO-specific protease HSAC015968 RPL34P2 AL049714 247903 −0.39984188 Ribosomal protein L34 pseudogene 2 IM8B_HUMAN TIMM8B NM_012459 279915 −0.39646264 Translocase of inner mitochondrial membrane 8 homolog B (yeast) P05209 K-ALPHA-1 NM_006082 334842 0.39265415 Tubulin, alpha, ubiquitous CYTB_HUMAN CSTB NM_000100 695 −0.39593616 Cystatin B (stefin B) MMDP_HUMAN MMD NM_012329 79889 0.35585533 Monocyte to macrophage differentiation- associated Q9H5J1 PREI3 NM_015387 107942 −0.39957843 Preimplantation protein 3 Q9Y283 INVS NM_014425 104715 0.38165914 Inversin S107_HUMAN S100A7 NM_002963 112408 −0.38002947 S100 calcium binding protein A7 (psoriasin 1) SR19_HUMAN SRP19 NM_003135 2943 −0.39927981 Signal recognition particle 19 kD MA17_HUMAN DD96 NM_005764 271473 −0.38289729 Epithelial protein up- regulated in carcinoma, membrane associated protein 17 O75943 RAD17 NM_002873 16184 −0.38971266 RAD17 homolog ( S. pombe ) THA_HUMAN THRA NM_003250 724 0.38475204 Thyroid hormone receptor, alpha (erythroblastic leukemia viral (v-erb-a) oncogene homolog, avian) HSAC008967 0 AK021982 287465 0.38611307 Homo sapiens cDNA FLJ11920 fis, clone HEMBB1000312 TFE2_HUMAN TCF3 M31523 101047 0.38678059 Transcription factor 3 (E2A immunoglobulin enhancer binding factors E12/E47) SUL2_HUMAN KIAA1247 AB033073 43857 0.39182636 Similar to glucosamine- 6-sulfatases HRA3_HUMAN HTRA3 AY040094 60440 0.38043383 Serine protease HTRA3 CN4A_HUMAN PDE4A NM_006202 89901 0.36750244 Phosphodiesterase 4A, cAMP-specific (phosphodiesterase E2 dunce homolog, Drosophila ) LTB2_HUMAN LTBP2 NM_000428 83337 0.36424793 Latent transforming growth factor beta binding protein 2 CSF2_HUMAN CSF2 NM_000758 1349 0.34759785 Colony stimulating factor 2 (granulocyte- macrophage) S109_HUMAN S100A9 NM_002965 112405 −0.38115533 S100 calcium binding protein A9 (calgranulin B) MAL2_HUMAN MAL2 NM_052886 76550 −0.37756452 Mal, T-cell differentiation protein 2 HSAC004288 LANO NM_018214 35091 −0.39020801 LAP (leucine-rich repeats and PDZ) and no PDZ protein P05209 K-ALPHA-1 NM_006082 334842 0.37816007 Tubulin, alpha, ubiquitous EMP3_HUMAN EMP3 NM_001425 9999 0.37961495 Epithelial membrane protein 3 LUM_HUMAN LUM NM_002345 79914 0.36091717 Lumican Q8NC43 FLJ23091 NM_024911 250746 0.4002659 Hypothetical protein FLJ23091 HRA1_HUMAN PRSS11 NM_002775 75111 0.38314991 Protease, serine, 11 (IGF binding) CAH6_HUMAN CA6 NM_001215 100322 0.38495881 Carbonic anhydrase VI SCGF_HUMAN SCGF NM_002975 105927 0.38520465 Stem cell growth factor; lymphocyte secreted C-type lectin CALD_HUMAN CALD1 NM_033138 325474 0.36017333 Caldesmon 1 SYH_HUMAN HARS NM_002109 77798 0.34476889 Histidyl-tRNA synthetase Q8IXQ7 LABH1 NM_032604 98608 0.36012503 Lung alpha/beta hydrolase 1 WEE1_HUMAN WEE1 X62048 75188 −0.38967133 WEE1+ homolog ( S. pombe ) Q9H0B8 DKFZP434B044 NM_031476 262958 0.36902739 Hypothetical protein DKFZp434B044 M1B1_HUMAN MAN1B1 NM_016219 279881 0.37430439 Mannosidase, alpha, class 1B, member 1 FBX8_HUMAN FBXO8 NM_012180 76917 −0.37436238 F-box only protein 8 SM3C_HUMAN SEMA3C NM_006379 171921 0.35697551 Sema domain, immunoglobulin domain (Ig), short basic domain, secreted, (semaphorin) 3C RB25_HUMAN CATX-8 NM_020387 150826 −0.38816294 CATX-8 protein ROL_HUMAN HNRPL NM_001533 2730 0.34146766 Heterogeneous nuclear ribonucleoprotein L FX37_HUMAN MGC11279 NM_024326 10915 −0.38119046 Hypothetical protein MGC11279 HSAC003262 KIAA0350 AB002348 23263 −0.39564135 KIAA0350 protein P05209 K-ALPHA-1 NM_006082 334842 0.37391308 Tubulin, alpha, ubiquitous BTE4_HUMAN KLF16 NM_031918 303194 0.40092333 Kruppel-like factor 16 MK_HUMAN MDK NM_002391 82045 −0.38900237 Midkine (neurite growth-promoting factor 2) Q9NRD9 DUOX1 NM_017434 272813 −0.3913498 Dual oxidase 1 P05209 K-ALPHA-1 NM_006082 334842 0.36936704 Tubulin, alpha, ubiquitous Z185_HUMAN ZNF185 NM_007150 16622 −0.36378851 Zinc finger protein 185 (LIM domain) TBG2_HUMAN TUBG2 NM_016437 279669 0.34203519 Tubulin, gamma 2 AAKC_HUMAN PRKAB2 NM_005399 50732 −0.35738949 Protein kinase, AMP- activated, beta 2 non- catalytic subunit HSAC006508 COL18A1 AF018081 78409 0.37705859 Collagen, type XVIII, alpha 1 Q9BSY6 ZD52F10 NM_033317 32343 −0.37419257 Hypothetical gene ZD52F10 SOX4_HUMAN 0 AJ420500 351928 −0.41521785 Homo sapiens mRNA full length insert cDNA clone EUROIMAGE 1977059 P05209 K-ALPHA-1 NM_006082 334842 0.37198391 Tubulin, alpha, ubiquitous MIC2_HUMAN MIC2 NM_002414 177543 0.36316608 Antigen identified by monoclonal antibodies 12E7, F21 and O13 VWF_HUMAN VWF NM_000552 110802 −0.36187757 Von Willebrand factor MFA5_HUMAN MAGP2 NM_003480 300946 0.34145531 Microfibril-associated glycoprotein-2 ELAF_HUMAN PI3 NM_002638 112341 −0.39367703 Protease inhibitor 3, skin-derived (SKALP) WD13_HUMAN WDR13 NM_017883 12142 0.35576479 WD repeat domain 13 PCB1_HUMAN PCBP1 NM_006196 2853 −0.35199657 Poly(rC) binding protein 1 DYHC_HUMAN DNCH1 AB002323 7720 0.36908919 Dynein, cytoplasmic, heavy polypeptide 1 Q8WUB2 HSU79274 NM_013300 150555 −0.41095099 Protein predicted by clone 23733 Q96N74 PGLYRP NM_052890 282244 −0.37818832 Peptidoglycan recognition protein L precursor HSAC018816 0 AK055723 310919 −0.37825237 Homo sapiens cDNA FLJ31161 fis, clone KIDNE1000028 PPL2_HUMAN PPIL2 NM_014337 93523 −0.34926253 Peptidylprolyl isomerase (cyclophilin)-like 2 HSAC015090 0 AK055294 211132 0.34738745 Homo sapiens cDNA FLJ30732 fis, clone FEBRA2000126, weakly similar to Mus musculus PDZ domain actin P05209 K-ALPHA-1 NM_006082 334842 0.36404497 Tubulin, alpha, ubiquitous DSG3_HUMAN DSG3 NM_001944 1925 −0.35916779 Desmoglein 3 (pemphigus vulgaris antigen) CTGF_HUMAN CTGF NM_001901 75511 0.36449331 Connective tissue growth factor Q96BW1 0 AK056354 91612 0.34964326 Homo sapiens , clone MGC: 23937 IMAGE: 3930177, mRNA, complete cds P05209 K-ALPHA-1 NM_006082 334842 0.36440521 Tubulin, alpha, ubiquitous HSAC020349 0 BC014584 348710 0.33020586 Homo sapiens , clone IMAGE: 4047062, mRNA G3P2_HUMAN GAPD NM_002046 169476 0.36112372 Glyceraldehyde-3- phosphate dehydrogenase DES1_HUMAN DESC1 NM_014058 201877 −0.37199135 DESC1 protein PAI2_HUMAN SERPINB2 NM_002575 75716 −0.39418824 Serine (or cysteine) proteinase inhibitor, clade B (ovalbumin), member 2 PYG2_HUMAN 0 BC006132 172084 0.36848424 Homo sapiens , clone IMAGE: 3627860, mRNA, partial cds CA17_HUMAN COL7A1 NM_000094 1640 0.35840992 Collagen, type VII, alpha 1 (epidermolysis bullosa, dystrophic, dominant and recessive) Q8NG54 FLJ21212 NM_024642 47099 −0.35274616 Hypothetical protein FLJ21212 [0000] TABLE 5 List of 61 genes with highest predictive value N+ UniProt Gene_symbol GB_accession UniGene_ID correlation Gene FSL1_HUMAN FSTL1 NM_007085 296267 0.53452734 Follistatin-like 1 ER22_HUMAN KDELR2 NM_006854 118778 0.52986731 KDEL (Lys-Asp-Glu- Leu) endoplasmic reticulum protein retention receptor 2 PCO1_HUMAN PCOLCE NM_002593 202097 0.52672595 Procollagen C- endopeptidase enhancer SPRC_HUMAN SPARC NM_003118 111779 0.51922531 Secreted protein, acidic, cysteine-rich (osteonectin) NC5R_HUMAN DIA1 NM_007326 274464 0.51482855 Diaphorase (NADH) (cytochrome b-5 reductase) HSAC009848 ZFP93 NM_004234 298089 0.50989391 Zinc finger protein 93 homolog (mouse) Q14521 LLGL2 NM_004524 3123 −0.50695888 Lethal giant larvae homolog 2 ( Drosophila ) Q8N6P7 IL22R NM_021258 110915 −0.49928496 Interleukin 22 receptor LEG1_HUMAN LGALS1 NM_002305 227751 0.48740219 Lectin, galactoside- binding, soluble, 1 (galectin 1) Q9BYD5 LOC84518 NM_032488 148590 −0.48449285 Protein related with psoriasis CQT6_HUMAN CTRP6 NM_031910 22011 0.47978614 Complement-c1q tumor necrosis factor- related protein 6 AD12_HUMAN ADAM12 NM_003474 8850 0.47905457 A disintegrin and metalloproteinase domain 12 (meltrin alpha) Q8N3N2 FLJ11196 NM_018357 6166 0.47772636 Hypothetical protein FLJ11196 Q96DR2 AK055031 44289 −0.47659518 Homo sapiens cDNA FLJ30469 fis, clone BRAWH1000037, weakly similar to UROKINASE PLASMINOGEN ACTIVATO P03996 ACTA2 NM_001613 195851 0.47560995 Actin, alpha 2, smooth muscle, aorta K6A2_HUMAN AK027727 184581 0.47396182 Homo sapiens cDNA FLJ14821 fis, clone OVARC1000556, highly similar to RIBOSOMAL PROTEIN S6 KINASE II TM29_HUMAN TRIM29 NM_012101 82237 −0.47250994 Tripartite motif- containing 29 TIM2_HUMAN AL110197 6441 0.47199573 Homo sapiens mRNA; cDNA DKFZp586J021 (from clone DKFZp586J021) MCA2_HUMAN JTV1 NM_006303 301613 0.46964142 JTV1 gene OPN3_HUMAN OPN3 NM_014322 279926 0.46101056 Opsin 3 (encephalopsin, panopsin) Q9UBG0 KIAA0709 NM_006039 7835 0.46012143 Endocytic receptor (macrophage mannose receptor family) TPM2_HUMAN TPM2 NM_003289 300772 0.46003075 Tropomyosin 2 (beta) INVO_HUMAN IVL NM_005547 157091 −0.45860578 Involucrin PEPL_HUMAN PPL NM_002705 74304 −0.44874989 Periplakin HSAC002603 FLJ11036 NM_018306 16740 −0.44841185 Hypothetical protein FLJ11036 TNR5_HUMAN TNFRSF5 NM_001250 25648 −0.44547341 Tumor necrosis factor receptor superfamily, member 5 FRIH_HUMAN FTH1 AK054816 62954 0.4396982 Ferritin, heavy polypeptide 1 P4H2_HUMAN P4HA2 NM_004199 3622 0.42478412 Procollagen-proline, 2-oxoglutarate 4- dioxygenase (proline 4-hydroxylase), alpha polypeptide II PS23_HUMAN SPUVE NM_007173 25338 0.42080095 Protease, serine, 23 HSAC011159 AF009267 102238 −0.46560322 Homo sapiens clone FBA1 Cri-du-chat region mRNA HSAC013320 AL162069 140978 −0.44362782 Homo sapiens mRNA; cDNA DKFZp762H106 (from clone DKFZp762H106) Q8N789 DKFZP434K0410 AL137589 152149 −0.43787021 Hypothetical protein DKFZp434K0410 O60335 KIAA0594 AB011166 103283 −0.42578156 KIAA0594 protein TCOF_HUMAN TCOF1 NM_000356 301266 0.38956707 Treacher Collins- Franceschetti syndrome 1 O14635 AF005082 113261 −0.45637623 Homo sapiens skin- specific protein (xp33) mRNA, partial cds GLSK_HUMAN GLS NM_014905 239189 0.43214995 Glutaminase Q9BRJ6 MGC11257 NM_D32350 334368 0.42954566 Hypothetical protein MGC11257 AQP3_HUMAN AQP3 NM_004925 234642 −0.42891866 Aquaporin 3 SPIB_HUMAN SPIB NM_003121 192861 −0.41021146 Spi-B transcription factor (Spi-1/PU.1 related) DRG1_HUMAN DRG1 NM_004147 115242 0.41879372 Developmentally regulated GTP binding protein 1 PHMX_HUMAN PHEMX NM_005705 271954 0.38728757 Pan-hematopoietic expression HSAC018335 AL137428 306459 −0.45404252 Homo sapiens mRNA; cDNA DKFZp761N1323 (from clone DKFZp761N1323) POSN_HUMAN OSF-2 NM_006475 136348 0.42814786 Osteoblast specific factor 2 (fasciclin I- like) DHC3_HUMAN CBR3 NM_001236 154510 −0.48089013 Carbonyl reductase 3 HSAC015262 AK021531 224398 0.43632187 Homo sapiens cDNA FLJ11469 fis, clone HEMBA1001658 Q14113 AEBP1 NM_001129 118397 0.42087649 AE binding protein 1 CRF_HUMAN CRH NM_000756 75294 −0.41353804 Corticotropin releasing hormone Q9NUJ7 FLJ11323 NM_018390 25625 −0.43842923 Hypothetical protein FLJ11323 Q96DU1 AKAP2 AJ303079 42322 −0.44106809 A kinase (PRKA) anchor protein 2 Q969Y7 MGC4677 NM_052871 337986 0.39455354 Hypothetical protein MGC4677 Q9BXY6 FLJ13962 NM_024862 330407 −0.44327759 Hypothetical protein FLJ13962 K1CW_HUMAN HAIK1 NM_015515 9029 −0.42594883 Type I intermediate filament cytokeratin HSAC019114 FLJ22622 NM_025151 324841 −0.4331912 Hypothetical protein FLJ22622 PGS2_HUMAN DCN NM_001920 76152 0.39882715 Decorin DCOP_HUMAN ODC-p NM_052998 91681 −0.41609162 Ornithine decarboxylase-like protein HSAC020747 0 AK056828 350748 −0.40822563 Homo sapiens cDNA FLJ32266 fis, clone PROST1000419 Q96F00 0 AK025719 251664 0.39457176 Homo sapiens cDNA: FLJ22066 fis, clone HEP10611 ISK5_HUMAN SPINK5 NM_006846 331555 −0.43770884 Serine protease inhibitor, Kazal type, 5 GFR1_HUMAN GFRA1 NM_005264 105445 0.37859516 GDNF family receptor alpha 1 AAF24516 NUDEL NM_030808 3850 −0.40726277 LIS1-interacting protein NUDEL; endooligopeptidase A O60836 T1A-2 NM_013317 135150 0.37127534 Lung type-I cell membrane- associated glycoprotein KLKA_HUMAN KLK10 NM_002776 69423 −0.40584943 Kallikrein 10

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CROSS-REFERENCE TO RELATED APPLICATIONS This application is a U.S. National Stage of International Application No. PCT/EP2011/071826, filed Dec. 6, 2011, claiming priority from German Application No. DE 1020 100 56221.1, filed on Dec. 24, 2010. BACKGROUND OF THE INVENTION The invention relates to a fastener, comprising a main body composed of a gas-tight and liquid-tight material, which serves to hold an object and can be affixed with the aid of an adhesive to a support surface. A fastener of this type which forms of a component of an assembly system is known from International Patent Publication No. WO 03/036106. This assembly system is used for the locally fixed attaching of objects such as towel holders, shelves, light fixtures or similar equipment articles to a wall, a ceiling or a similar surface, in particular in rooms having walls coverings of tiles, marble slabs or the like. The assembly system consists of different types of fasteners and an adhesion or bonding agent, which can be an aerobic adhesive, wherein the shape of the fasteners must be adapted in dependence on the purpose. Systems of this type have the disadvantage of requiring extremely long curing times for the adhesive, which can last up to twelve hours, thereby considerably reducing the ease of installation of the systems. In cases where the environmental conditions are dry and cold, the adverse effects on the curing process can be particularly strong. The fastener serves to receive an element that holds the object and comprises a main body which is provided at the back side facing the wall with a recess and a filling opening that empties into the latter. Adhesive and/or bonding agent is introduced via this opening into the space between the fastener and the wall. The back side of the main body, which is facing the wall, is sufficiently liquid-permeable and gas permeable, at least in some regions, so that the gas that develops during the curing of the adhesive and bonding agent in the recess can escape and/or volatile bonding agents can evaporate and environmental air can simultaneously come into contact with this adhesive and bonding agent, thereby allowing a curing of the adhesive agent and ensuring a stable and load-bearing fixation of the fastener on the wall. The disadvantage of the above described system is that the adhesive and bonding agent must always be in contact with environmental air via the gas-permeable and liquid-permeable wall of the main body to ensure a sufficient curing. As a result, the structural design options for the fastener are strongly restricted in an undesirable manner. A fastening agent composed of a mixture of an aerobic adhesive and a hydrophilic substance is known from the International Patent Publication No. WO 2009/156013 A1. By adding the hydrophilic substance to the aerobic adhesive, a fastening agent mixture is formed which no longer requires surface contact with moist environmental air in order to cure from this surface inward. Rather, the hydrophilic substance dispersed in the aerobic adhesive that is contained in the mixture ensures that the aerobic adhesive in the mixture can cure from the inside out, even if there is no contact with the external environmental air containing the moisture. The moisture needed for the curing and/or the required oxygen are present in the hydrophilic substance itself since this substance contains enough moisture, owing to its hydrophilic characteristics, to meet the curing requirements for the mixture that forms the fastening agent. With the fastening agent embodied in this way, an object can be secured easily on a support by applying a layer of the fastening agent between the object and the support. When using the fastening agent, it is critical that the components are mixed together just prior to the use. An assembly set is provided for this which contains two receptacles for the separate storage of the aerobic adhesive and the hydrophilic substance. The desired amounts of the components can then be removed from these receptacles for the mixing of the fastening agent, wherein a spatula is used for the mixing. Following this, a layer of the fastening agent is applied to the object, and the object is subsequently affixed to the support surface by pressing the layer of fastening agent against the support surface. The aerobic adhesive in this layer thus cures as a result of the moisture contained in the hydrophilic substance. SUMMARY OF THE INVENTION It is an object of the present invention to create a fastener of the aforementioned type which is easy to handle and can be used flexibly while still having a high functionality. The above and other objects are achieved according to the invention which provides, in one embodiment, a fastener arrangement, comprising: a main body, including a gas-tight and liquid-tight material, to hold an object, the main body defining a cavity and being fixable to a support surface; a hydrophilic insert attached to the main body inside of the cavity for facing the support surface and adapted to receive a metered amount of moisture; and an aerobic adhesive for application to the hydrophilic insert so that the aerobic adhesive is encapsulated gas-tight and liquid-tight together with the hydrophilic insert in the cavity enclosed by the support surface and the main body when the main body is fixed on the support surface. With the fastener according to the invention, objects can be affixed securely to support surfaces, without requiring structural interventions involving screws or the like on the support surfaces or the objects. An aspect of the invention lies in the interaction between the aerobic adhesive and the hydrophilic insert in the fastener. As a result of the contact between the aerobic adhesive and the hydrophilic insert to which moisture is supplied in a metered fashion, the aerobic adhesive can cure over its complete volume, without the necessity of coming into contact with the environmental air. With the aid of this aerobic adhesive that interacts with the hydrophilic insert, a permanent, reliable and above all quickly available fastening of objects is made available, that is to say without the use of screws or similar mechanical fastening means. An advantage, especially as compared to the fastening agent known from International Patent Publication No. WO 2009/156013 A1, is that mixing together an aerobic adhesive with a hydrophilic substance is no longer required. Rather, the mechanical contact alone between the aerobic adhesive and the hydrophilic insert, which occurs when the aerobic adhesive is applied to this hydrophilic insert, is sufficient to ensure a complete curing of the aerobic adhesive despite a completely gas-tight and liquid-tight encapsulation of the aerobic adhesive between the support surface and the main body of the fastener. A time consuming mixing of an aerobic adhesive with a hydrophilic substance is thus omitted, thereby making it considerably easier to assemble the fastener. The ease of assembly is further increased in that the hydrophilic insert may be attached either with the aid of an adhesive agent or with a mechanical fastening device to the inside of the main body. The main body and the hydrophilic insert consequently form a structural unit to which only the aerobic adhesive must be supplied in order to attach the fastener to the support surface. A further advantage of the invention is that the aerobic adhesive and the hydrophilic insert are encapsulated gas-tight and fluid-tight in the cavity between the support surface and the main body. As a result, the curing process of the aerobic adhesive within the encapsulation occurs completely independent of the environmental conditions and is thus highly reproducible. Depending on the climate conditions, the hydrophilic insert coming into contact with the environmental atmosphere might absorb either too much or too little moisture to ensure a defined curing process for the aerobic adhesive. These types of interfering influences are systematically removed by cutting off the aerobic adhesive from the environmental atmosphere and as a result of metering in the liquid prior to the use of the fastener. It is advantageous if moisture is supplied in a metered fashion to the hydrophilic insert by guiding a wetted cloth over the insert. Moisture can thus be supplied easily and at the same time in a metered fashion. According to one advantageous embodiment of the invention, the aerobic adhesive is composed of silane MS polymers. The hydrophilic insert may be embodied as a plate-shaped insert that is composed of cotton or a composite fiber material. Alternatively, the hydrophilic insert may be embodied in the form of a sintered plate, composed in particular of plastic, stainless steel or brass. The hydrophilic insert can generally also consist of a hydrophilic coating, preferably composed of the aforementioned materials, wherein the hydrophilic coating is advantageously applied to an insert body or directly to the main body. One structural embodiment of the fastener provides that the main body is provided with an edge segment that extends along its circumference and is raised, relative to the inside of a base plate for the main body, on which the hydrophilic insert rests. The inside of the main body is thus recessed, with the hydrophilic insert placed into it and attached thereto. The cross-sectional surface of the hydrophilic insert may be adapted to the surface area on the inside, so that the hydrophilic insert is positioned essentially form-locking or tightly fitting in this recess. A fixation ring may be fitted onto the edge segment forming the main body, by which the main body can be fixated ahead of time on the support surface. The fixation ring in particular consists of a double-sided adhesive tape. The pre-fixation of the fastener facilitates its assembly since the fastener can thus be fixated ahead of time in the desired position on the support surface, meaning before the aerobic adhesive is applied to the hydrophilic insert and/or before the curing of the aerobic adhesive on the hydrophilic insert. According to one embodiment, the base plate of the main body may be closed completely. In that case, the aerobic adhesive may be applied to the exposed top of the hydrophilic insert that is positioned in the main body before the fastener is fitted onto the aerobic insert. According to a anther embodiment, the base plate and the hydrophilic insert attached to its inside may be punctuated by at least one bore hole, wherein aerobic adhesive can be inserted via this bore hole into the cavity between the main body and the support surface. In that case, the fastener can be placed onto to the support surface prior to applying the aerobic adhesive and can be held in place thereon with the aid of the fixation ring. The aerobic adhesive can subsequently be pressed through the bore hole into the cavity between the main body and the support surface, so that the adhesive forms a homogeneous layer on the hydrophilic insert. It may be advantageous if the base plate and the hydrophilic insert attached to its inside are punctuated by at least one bore hole through which excess aerobic adhesive can exit from the cavity between the main body and the support surface. In those cases, some excess aerobic adhesive remains inside the bore holes and ensures an air-tight encapsulation of the aerobic adhesive on the inside which is in contact with the hydrophilic insert. BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention is explained with the aid of the drawings, wherein: FIG. 1 a is a view from above of the front of a first exemplary embodiment of the fastener according to the invention; FIG. 1 b is a view from above of the back side of a first exemplary embodiment of the fastener according to the invention; FIG. 1 c is a sectional view through the fastener as shown in FIGS. 1 a and 1 b; FIG. 2 a is a view from above of the front of a second exemplary embodiment of the fastener according to the invention; FIG. 2 b is a view from above of the back side of a second exemplary embodiment of the fastener according to the invention; FIG. 2 c is a sectional view through the fastener as shown in FIGS. 2 a and 2 b; FIG. 3 shows a fastener comprising a magnetic holder; FIG. 4 shows an application example for the fastener according to FIG. 3 . DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 a to 1 c show a first exemplary embodiment of the fastener 1 according to the invention. In this embodiment, the fastener 1 comprises a main body 2 of which the front is shown in FIG. 1 a and the back in FIG. 1 b . FIG. 1 c shows a sectional view through the fastener 1 . The main body 2 consists of a solid, gas-tight and liquid-tight material, in particular a metal such as aluminum. The main body 2 has a circular disc shape and is completely closed in the present case. Bolts, threads or similar adapters, which are not shown herein, can be provided on the back side of the main body 2 in order to position and fixate specific objects on the fastener 1 . The fastener 1 embodied in this way can be used in particular for holding accessories in bathrooms, sanitary rooms or also to secure objects to the inside or the outside of buildings, for example such objects as grates for holding plants, curtain rods, shower profiles and the like. The main body 2 in the present case consists of a circular disk-shaped base plate 2 a , wherein a ring-shaped edge segment 2 b which projects over the inside the base plate is provided on the inside along the circumference of the base plate. The inside of the base plate 2 a is therefore recessed, relative to the edge segment 2 b. A hydrophilic insert 4 is inserted into this recessed area and is fixated therein. The fixation can be realized as mechanical fixation or in the form of an adhesive agent. The hydrophilic insert 4 can take the form of a plate-shaped insert composed of cotton or a composite fiber material. Alternatively, the hydrophilic insert 4 can also be a sintered plate composed, for example, of plastic, stainless steel or brass. The hydrophilic insert 4 is embodied plate shaped, wherein its geometries are adapted to the main body 2 in such a way that the hydrophilic insert 4 extends over the complete inside area of the base plate 2 a and fits tightly against the edge segment 2 b of the main body 2 . Alternatively, the hydrophilic insert 4 can also extend only over partial areas of the base plate 2 a. The thickness of the material for the hydrophilic insert 4 is selected such that the insert is positioned lower, relative to the upper edge of the edge segment 2 b. It is obvious from FIGS. 1 a and 1 c that a fixation ring 5 is fitted onto the upper edge of the edge segment 2 b and extends over the complete circumference of the edge segment 2 b . The fixation ring 5 is used to pre-position the fastener 1 on a support surface, not shown herein, to which the fastener 1 is to be attached. The fixation ring 5 advantageously consists of a double-sided adhesive tape. To permanently install the fastener 1 on a support surface, for example on the wall or ceiling of a building, moisture is first metered into the hydrophilic insert 4 , for example by swiping a moistened cloth over the hydrophilic insert 4 . A layer of aerobic adhesive is then applied to this moistened hydrophilic insert 4 . The aerobic adhesive may be composed of a silane MS polymer. Following this, the main body 2 of the fastener 1 is placed onto the support surface, so that the fixation ring 5 comes in contact with the support surface and the desired pre-positioning is achieved. As a result, the aerobic adhesive is located inside a completely enclosed cavity formed by the support surface and the main body 2 . Despite the gas-tight and air-tight encapsulation of the aerobic adhesive, this adhesive cures completely since it is supplied by the hydrophilic insert 4 with the necessary moisture for the curing process. Owing to the metered-in supply of moisture to the hydrophilic insert 4 , the aerobic adhesive is provided with precisely the amount of moisture needed for a complete curing. As a result of the gas-tight and liquid-tight encapsulation, the aerobic adhesive is protected against environmental influences, in particular against fluctuations in the humidity of the air which, upon contact with the aerobic adhesive, could result in too much or too little moisture being supplied to the aerobic adhesive, thereby possibly causing an incomplete curing of the aerobic adhesive. Since a complete curing of the aerobic adhesive is achieved through the encapsulation of the aerobic adhesive and its contact with the moistened hydrophilic insert 4 , an excellent, permanent adherence of the fastener 1 on the support surface is achieved. FIGS. 2 a to 2 c show a variant of the embodiment according to FIGS. 1 a to 1 c . The embodiment according to FIGS. 2 a to 2 c is provided with bore holes 6 , 7 which punctuate the base plate 2 a and also the hydrophilic insert 4 attached to it. Otherwise, the embodiment shown in FIGS. 2 a to 2 c corresponds fully to the embodiment shown in FIGS. 1 a to 1 c. With the exemplary embodiment shown in FIGS. 2 a to 2 c , the hydrophilic insert 4 is initially provided with moisture in a metered fashion. In contrast to the exemplary embodiment according to FIGS. 1 a to 1 c , the fastener 1 shown herein can be pre-fixated 5 on the support surface with the aid of the fixation ring 5 , prior to applying the aerobic adhesive to the hydrophilic insert 4 . In the present case where the fastener 1 is pre-fixated on the support surface, aerobic adhesive is inserted via one or both bore holes 6 into the cavity between the main body 2 and the support surface. The aerobic adhesive inserted in this way then forms an adhesive layer between the support surface and the hydrophilic insert 4 . Excessive aerobic adhesive can exit via the bore holes 7 . Residual aerobic adhesive inside the bore holes 6 , 7 seals these bore holes 6 , 7 so that the layer of aerobic adhesive between the support surface and the hydrophilic insert is again encapsulated gas-tight and liquid-tight, in the same way as for the embodiment according to FIGS. 1 a to 1 c . A controlled and complete curing of the layer of aerobic adhesive between the support surface and the hydrophilic insert 4 is consequently also achieved in this case since the aerobic adhesive therein contains only metered-in moisture from the hydrophilic insert but not from the environmental atmosphere. The bore holes 6 , 7 can furthermore meet the additional function of serving as mechanical fixation for the hydrophilic insert 4 in the main body 2 , wherein the bore holes 6 , 7 in particular are used for installing rivet connections. FIG. 3 shows an embodiment of a fastener 1 with a magnetic holder. The fastener 1 in this case has a hollow-cylindrical main body 2 . FIG. 3 shows a view of the exposed top of the main body 2 . A magnet 8 is positioned somewhat recessed in the main body 2 , in such a way that it is freely accessible via the exposed top of the main body 2 . According to the embodiment shown in FIGS. 1 a to 1 c , the hydrophilic insert 4 is located on the underside of the main body 2 . By applying aerobic adhesive to the hydrophilic insert 4 , the fastener 1 embodied in this way can be installed on a support surface. FIG. 4 shows an application example for the fastener 1 according to FIG. 3 . The fastener 1 is attached to a wall element 9 with the aid of aerobic adhesive that is applied to the hydrophilic insert 4 , for example used inside a motor vehicle. A refuse container 10 is provided with a ball joint on its outer wall. The metal ball 11 of the ball joint is inserted into the exposed top of the fastener 1 and is held in place therein by the magnetic forces of the magnet 8 . As a result, the refuse container is attached pivoting on the fastener 1 .

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BACKGROUND OF THE INVENTION Bacteria from the hand of a surgeon or other operating room personnel can be the source of serious infections in surgery patients. While transfer of bacteria is substantially reduced by routine surgical scrubbing procedures, it is prudent to take additional steps to eliminate bacteria and other microorganisms that may grow under surgical gloves. If left unchecked, these organisms could escape through an all too common puncture to the glove and infect the patient. To this end, a germicidal solution is often coated onto the hands before slipping on surgical gloves. Optimally, the coating remains on the skin surface of the hands during a surgical operation to inhibit bacterial growth of bacteria. However, current germicidal solutions cause significant drying of the skin, and do not provide a coating which allows for easy donning or removal of surgical gloves. Therefore, an object of the present invention is to provide a composition which is an effective germicide with a high level of moisturizing activity on the skin of the user. Another object is to provide an effective germicidal composition which may be coated onto skin to provide an antiseptic film which will allow for ready placement and removal of gloves over the skin. SUMMARY OF THE INVENTION These and other objects are achieved by the present invention which is directed to a lubricating germicidal composition, and a method of using the composition as an antiseptic lotion for the hands or a disinfectant for inanimate objects. The composition contains isopropanol, a germicidally-active quaternary ammonium salt, cetyl alcohol and glycolic acid. The quaternary ammonium salt is an effective germicide for vegetative cells, fungi, algae and viruses. The combination of isopropanol and quaternary in the present composition provides substantially instant disinfection of a surface on contact, and a synergistic effect which increases the effectiveness of each of their respective activities as a germicide. In addition, the alcohol provides an initial fast-acting germicidal activity, and evaporates leaving a germicidal residue of the quaternary substantially evenly distributed over the surface for a lasting germicidal effect, particularly when the treated surface becomes wet. This feature provides a distinct advantage for retaining the composition on the treated surface in the event that the treated surface is contacted with an infectious material. The germicidal residue remains on the surface and will retain its activity on an undisturbed surface for up to about 1 year, or until the composition is removed by washing the treated surface, for example, with conventional soap and water. The cetyl alcohol and glycolic acid in the composition act in combination to prevent drying of the skin following application of the alcohol and to add lubricity to the composition. The cetyl alcohol further acts as an emollient and emulsion modifier in the composition. The glycolic acid is a newly recognized cosmetic additive with moisturizing properties. The invention further provides a method of inhibiting microbial growth on a substrate by contacting the surface of the substrate with the germicidal composition. The composition may be used as a disinfectant for countertops and other inanimate objects, or as an antiseptic lotion which is applied to the hands or other skin surface. The composition forms a protective germicidal barrier when applied to the skin or other hard surface. In a preferred use, the composition is used in conjunction with gloves or other protective outerwear that are utilized, for example, by a surgeon or other health care provider, a food handler, and the like. The composition provides a moisturizing germicidal film on the surface of the skin which act as an antiseptic "invisible glove" beneath a surgical or other plastic glove. The invention also contemplates an article of manufacture, or kit, for use in inhibiting microbial growth on a substrate. The kit is composed of, in combination, the germicidal composition packaged within containing means, optionally with instruction means comprising information for the use of the composition and/or other related literature, a pair of surgical glove or other outerwear, and/or a cloth or other material for applying the composition. DETAILED DESCRIPTION OF THE INVENTION The invention provides a topical, lubricating, germicidal composition for applying to a substrate such as the hands or an inanimate object. The composition is an alcoholic solution containing cetyl alcohol, glycolic acid, benzalkonium chloride, and a major amount of isopropyl alcohol. The composition is an effective germicide against bacteria, fungus, yeast, and viruses, and for alleviating or preventing drying of the skin of the user. Cetyl alcohol, a C 16 fatty alcohol, is included in the composition as an emulsifier and as a lubricant to allow gloves to be more easily slipped onto and off of the hands. The composition contains about 3 wt-% cetyl alcohol, preferably about 2-3 wt-%, more preferably about 2.5 wt-%. The composition includes an effective bactericidal amount of benzalkonium chloride, a quaternary ammonium antimicrobial agent that is commercially available, for example, as Zephiran® chloride (Winthrop), 17% concentrate. The alkyl groups of the quaternary range from C 8 to C 18 . The composition includes about 0.1-1.5 wt-% of the 17% solution of benzalkonium chloride, preferably about 0.1-1 wt-%, more preferably about 0.13%. The composition is formulated with a major amount of isopropyl alcohol. Although not intended to limit the scope of the invention, it is believed that the isopropyl alcohol enhances the germicidal action of the remaining ingredients, particularly the bactericidal effects of the benzalkonium chloride. The isopropyl alcohol also provides for an even distribution of the ingredients over the skin or other substrate. The composition includes about 90-98% isopropyl alcohol, preferably about 95%. Surprisingly, it has been found that the combination of cetyl alcohol and glycolic acid with the other named ingredients provides a composition having a high level of germicidal activity with increased lubricating effects which enhance the feel of the composition on the skin of the user. The glycolic acid and cetyl alcohol act to prevent drying of the skin by the isopropyl alcohol in the composition. To achieve this level of activity, the composition includes an effective lubricating amount of glycolic acid, preferably about 0.1-1 wt-%, preferably about 0.2-0.4 wt-%, more preferably about 0.25 wt-%. The composition may optionally include minor amounts of additive agents for specific uses as desired. The composition contains the ingredients in a concentration such that dilution by water on the skin or in spills of contagious material will not diminish or interfere with its effectiveness as a germicide. The concentration of ingredients in the composition is effective to decrease the microbial count on the skin or other substrate by about 95-100% within about 5-40 seconds after contact, more preferably within about 5-10 seconds. In a preferred embodiment of the invention, the lubricating germicidal composition is formulated with about 1-3 wt-% cetyl alcohol, about 0.1-0.4 wt-% glycolic acid, about 0.1-1 wt-% benzalkonium chloride, and about 90-98 wt-% isopropyl alcohol. The present germicidal compositions exhibit improved efficacy as a combination germicide and moisturizing lotion, and have particular usefulness as an antiseptic lotion applied to the hands or other skin surfaces. The mixture of ingredients synergistically provide a germicidal effect and an improved moisturizing effect on the skin. The composition also enables gloves, such as surgical gloves and the like, to be more easily slipped over the skin. The composition when dried on the skin remains intact as a film and provides a persistent residual germicidal coating on the surface of the skin until washed off. The composition may be removed by washing with a commercial hand soap or other like detergent. On a hard surface, undisturbed, the germicidal residue can last up to about one year. The compositions are an effective germicide against a wide assortment of microorganisms. The composition is effective in destroying gram-negative and gram-positive organisms on contact. For example, the composition may be used as an effective bactericide, for example, against Staphylococcus aureus, Staphylococcus epidermidis, Salmonella cholerasuis, Escherichia coli, Klebsiella pneumoniae, Listeria monocytogenes, Streptococcus pyogenes, Enterobacter agglomerans, Serratia marcescens, Legionella pneumophila, Leucothrix mucor, and Mycobacterium tuberculosis, and the like. The composition provides effective fungicidal action against organisms such as Candida albicans, Trichophyton mentagrophytes, Aspergillus niger, Myrathecium verrucaria, Trichoderma viride, Chaetomium globosum, and the like. The composition is also an effective algicide against algae such as Stigeoclonium spp., Oscillaturia tenuis, Anacystis cylindrica and other like blue-green algae, and the like. In addition, the composition possesses effective virucidal activity against such viruses as hepatitis B virus, rhinovirus, parainfluenza virus, adenovirus, rabies, and human immunodeficiency virus (HIV), hydrophilic viruses such as Coxsackie virus, echo virus, and poliovirus, lipophilic viruses such as herpes simplex, vaccinia virus, and influenza virus, and the like. It is also effective in destroying cysts of protozoa such as Entamoeba histolytica. The compositions are generally prepared by combining the ingredients in a suitable mixing vessel. The ingredients may be added simultaneously or sequentially, and mixed together to form an alcoholic solution. The compositions may be prepared at about room temperature (25° C.), and are stable for up to about 6-12 months when stored at about room temperature (25° C.). The germicidal compositions of the invention are advantageously used by persons whose occupation requires them to wear gloves, for example, a surgeon, food handler, hair dresser, and the like. In use, the composition is applied topically to the hands, preferably following a pre-operative scrub-up or other hand wash with a detergent or antiseptic. The isopropyl alcohol is allowed to evaporate, wherein a film-like coating is formed on the surface of the skin. The composition remains on the surface of the skin for a period of time until washed off. Advantageously, the composition may be retained on the skin to provide a continuous residual germicidal action over an extended period of time until washed off. To achieve such extended germicidal activity, a glove made of plastic, latex, rubber and the like, for example, a surgical glove, or other like outerwear, may be placed over the dried composition on the skin. The combination of ingredients provides a composition which will form a film on the skin surface which is smooth and slippery to the touch to allow gloves to be more easily slipped on and off the hands, thus facilitating a handling step where accidental bacterial contamination could occur. In addition, the ingredients, particularly the glycolic acid, reduces dehydration of the skin from wearing gloves over an extended period of time. The composition may also be used as a disinfectant to disinfect inanimate objects such as countertops, examination tables, especially after spills of infectious material in a hospital or laboratory setting where hazardous wet spills are frequently encountered, and the like. In use, the substrate to be disinfected is contacted with the composition by spraying, wiping with a cloth or sponge, submersion in a container of the composition, and the like. The composition is allowed to remain on the surface of the object until it evaporates. The germicidal composition may remain on the object, or may be removed either by wiping or rinsing with soap and water. Additionally, the composition may be used as a rapid spray on hazardous spills of patient secretions, excretions, blood, and the like. The germicidal composition may be packaged as an article of manufacture, or kit, for use in disinfecting inanimate objects and as an antiseptic lotion on skin surfaces. The kit includes, the composition packaged within containing means, for example, a foil or plastic pouch, or a vial, jar or other like container, optionally with means for spraying, or impregnated in a packaged absorbent fibrous or cellular sheet material which may be dropped, pressed, or rubbed onto the surface of the skin or object to release an effective amount of the composition thereon, and other like containers. The kit may further include instruction means composed of information relating to the use of the composition, pharmaceutical information, and other like literature, and/or, gloves such as surgeons gloves, and/or a cloth, tissue or other cellulosic material for spreading the composition onto a hard surface. The instruction means may be in the form of a label or tag attached to the packaging, or a printed package insert within the packaging and the like. The invention will be further described by reference to the following detailed examples, wherein the methodologies are as described below. These examples are not meant to limit the scope of the invention that has been set forth in the foregoing description. Variation within the concepts of the invention are apparent to those skilled in the art. The disclosures of the cited references are incorporated by reference herein. EXAMPLE I Preparation of Germicidal Lubricating Lotion A germicidal composition was prepared with the ingredients as shown in Table I, below. TABLE I______________________________________ AMOUNT WEIGHT %______________________________________Cetyl Alcohol 2000 gm 2.5%Zephiran Concentrate (17%) (615 ml) 0.13% 104.55 gmGlycolic Acid 200 gm 0.25%Isopropyl Alcohol Q.S. 80,000 ml 96%______________________________________ To prepare a germicidal lotion, 2000 grams cetyl alcohol (Ciba-Geigy Corp., Woodbridge, N.J.), 250 grams glycolic acid (hydroxyacetic acid; Aldrich Chemical Company) and 615 ml benzalkonium chloride (Zephiran chloride, concentrate, 17%; Winthrop Pharmaceuticals, New York, N.Y.) were dissolved in isopropyl alcohol (99%) and mixed at room temperature until enough isopropyl alcohol was added to the mixture to form a 80 liter solution. The final composition contained 2.5% cetyl alcohol, 0.13% benzalkonium chloride, 0.25% glycolic acid, and 96% isopropyl alcohol (99%). EXAMPLE II Use of the Germicidal Lubricating Lotion as an Antiseptic The composition prepared in Example 1 was applied to the surface of the hands to test its effectiveness against normal skin flora such as staphylococci, micrococci, and diphtheroids. Samples of bacteria were taken from the surface of the hands prior to application of the composition. The composition (1-2 ml) was sprayed onto the hands as a thin coating. The isopropyl alcohol evaporated within 2-4 seconds, and the composition formed as an even, inconspicuous film on the skin surface. After 1.5 hours, samples were again taken from the skin surface. The bacterial counts before and after applying the composition is shown in Table II below. TABLE II______________________________________ FINGER TIPS FINGER TIPS LEFT HAND RIGHT HAND______________________________________Pre-Treatment 102 37Post-Treatment.sup.1 5 1% Reduction 95% 97%______________________________________ .sup.1 Following wetting of the hand with 1-2 ml of the composition and allowing the composition to air dry.

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The invention relates to a method for determining the ignitability of fuel, particularly diesel, biodiesel, gas-to-liquid (GTL) or biomass-to-liquid (BTL) fuel, with an unknown fuel quality, which is specified for use in an internal combustion engine. TECHNICAL FIELD Fuels for diesel engines of motor vehicles, such as diesel, biodiesel or gas-to-liquid fuel, i.e. liquid fuel obtained from natural gas, partially have very different fuel qualities. Particularly the ignitability of the fuel, which is very important for the combustion in the cylinders of diesel engines and is usually expressed as the cetane index CCI or the cetane number, can vary considerably for different fuels, a bandwidth of the cetane index being definitely possible between values of 38 for diesel fuel in the USA and approximately 70 for GTL fuel. BACKGROUND In light of such a large range of fuel qualities, it is no longer possible with regard to the operation of an internal combustion engine at every engine operating point to find suitable parameters for the open-loop or closed-loop control of the combustion in the cylinders, as for example the quantity of injected fuel, the point in time of pilot and main injections, the rail pressure of a common rail fuel injection system, the quantity of fresh air supplied to the cylinders, the supercharging pressure in supercharged internal combustion engines, the throttle valve position etc., with which good results with regard to emissions and drivability of the motor vehicle can be obtained for all of the fuel qualities. That is why practical methods are needed, with which the ignitability of the fuels used in the operation of the internal combustion engine, respectively the motor vehicle, can be ascertained with sufficient accuracy. Such methods have already been proposed, wherein the quality and particularly the ignitability of the fuel being used is derived from the progression of the cylinder pressure. What is considered a disadvantage in these methods is, however, that the installation of an additional cylinder pressure sensor is required and that the measurement of the cylinder pressure can only be performed in a special operating mode of the internal combustion engine. Based on this fact, the task underlying the invention is to improve a method of the kind mentioned at the beginning of the application to such an extent that the determination of the ignitability of fuel with an unknown fuel quality can be performed during the normal operation of the internal combustion engine and without necessitating the use of additional sensors. SUMMARY The task is thereby solved according to the invention, in that the density of the fuel is ascertained, and the ignitability of the fuel is derived from this. The idea behind the invention is that the cetane index, which serves as a measurement for the ignitability of fuels for diesel engines, can according to ASTN D976 be determined by empirical formulas, into which only the distillation range, respectively a corrected average boiling temperature of the fuel, besides the density ρ of the fuel at a specified temperature goes. Because the distillation range, respectively the corrected average boiling temperature of the fuel, for all of the fuels used in diesel engines can be assumed as approximately constant, a definite relationship consequently ensues between the density ρ of the fuel and the cetane index CCI, so that this can be calculated when the density ρ is known. While a determination of the fuel density from the mass and the volume of the fuel contained in a fuel tank of the internal combustion engine is not possible without additional sensors and in addition is largely inaccurate due to the fluctuating fluid levels, the mass as well as the volume of the fuel injected into a cylinder of the internal combustion engine can be obtained from information or data, which are required for the closed-loop or open-loop control of the combustion in the cylinders of modern motor vehicle engines and consequently are as a rule already provided by indicators, sensors or probes present in the internal combustion engine, respectively the motor vehicle. Provision is, for example, made in a preferred configuration of the invention for the mass of the fuel, which is delivered into a cylinder of the internal combustion engine during an injection, to be determined from the mass of the fresh air delivered into this cylinder for combustion and the combustion-air ratio (air ratio) λ in the combustion exhaust gas discharged from the cylinder, in that the combustion-air ratio λ is measured during a time period, wherein the injected fuel quantity and the quantity of fresh air being supplied are maintained at a constant level. In internal combustion engines with a common rail fuel injection system, the volume of the fuel delivered into a cylinder of the internal combustion engine during one injection does not have to be ascertained with sensors but can be calculated according to a further preferred configuration of the invention from the rail pressure as well as from the duration of the activation of the injectors of the fuel injection system. This results from the fact that the volume of the injected fuel is established by these variables. The backpressure in the cylinder and the temperature of the fuel measured by a temperature sensor of the fuel injection system are, however, thereby preferably taken into account because the accuracy of the calculation of the injected fuel volume from the rail pressure as well as from the duration of the activation of the injectors can be improved in this way. Because in diesel internal combustion engines, the mass of the fresh air delivered into the cylinder, which is measured by an air mass sensor of the internal combustion engine, and the combustion-air ratio, which is measured by a lambda probe in the exhaust gas tract of the internal combustion engine, are normally transferred in the form of sensor signals with data to an engine control unit of the internal combustion engine for evaluation, it is particularly advantageous if at least the determination of the mass of the fuel injected into the cylinder of the internal combustion engine is performed on the basis of these data. Because the determination of the fuel volume delivered into a cylinder of the internal combustion engine for one injection takes place mathematically, it can, however, likewise be advantageously performed by a processor of the engine control unit of the internal combustion engine just like the ascertainment of the density of the fuel from mass and volume as well as the mathematical derivation of the ignitability, respectively of a cetane index, from the calculated density of the fuel. An absolute value for the mass and/or for the density of the fuel is preferably ascertained on the basis of models in the engine control unit. A reference value for the mass and/or for the density of the injected fuel can, however, alternatively or additionally be determined for a fuel with a known fuel quality and can be compared in predetermined time intervals with the mass and/or the density of the injected fuel, which were ascertained for the same fuel. This is done in order that allowance is made for deviations due to deterioration when ascertaining the mass of the fuel and/or the fresh air mass delivered into the cylinder. Because rapid changes in the density of the fuel can suggest the use of a fuel with a different fuel quality, the density of the fuel is advantageously ascertained before a filling of the fuel tank (fueling). In so doing, a filling of the tank (fueling) can be suggested from a change in the fill level of the fuel in a fuel tank, an opening of a fuel filler flap and/or a calculation of the fuel consumption of the internal combustion engine. If the occasion arises that the density of the fuel being used and thereby the ignitability of the fuel, which was ascertained via the density, have changed, a portion of the significant parameters designated for the open-loop or the closed-loop control of the combustion in the internal combustion engine, such as air mass, initiation of activation and rail pressure, or nominal value characteristic diagrams of these parameters is changed in such a way than an optimal combustion once again takes place. BRIEF DESCRIPTION OF THE DRAWING In the following, the invention is explained in detail using one of the examples of embodiment depicted in the drawing. The following are shown: FIG. 1 is a schematic view of parts of a motor vehicle with a diesel engine; FIG. 2 is a block diagram of a method for determining the ignitability of fuel for the diesel engine according to a first variation; and FIG. 3 is a block diagram of a modification of the method from FIG. 2 . DETAILED DESCRIPTION The motor vehicle 2 schematically depicted in FIG. 1 of the drawing has a diesel engine 6 , which is selectively supplied with diesel, biodiesel or gas-to-liquid (GTL) fuel from a fuel tank 4 , with a common rail fuel injection system 8 , which is activated by an engine control unit 10 . The diesel engine 6 has in a known manner an intake tract 12 with an air mass flow meter 14 for measuring the fresh air mass delivered into the cylinders 16 of the engine 6 and a throttle valve 18 for controlling the fresh air supply as well as an exhaust gas tract 20 with a lambda probe 22 for measuring the combustion-air ratio (air ratio λ) of the combustion gases discharged from the cylinders 16 . The fuel injection system 8 comprises likewise in a known manner a plurality of injectors or injection valves 24 , which are supplied with fuel from the fuel tank 4 by a fuel pump 26 and a high pressure piston pump 28 via a common manifold (rail) 30 . The fuel line 32 leading from the fuel tank 4 to the fuel distributor rail 30 comprises besides a fuel filter 34 and both pumps 26 , 28 additionally a pressure control valve 36 for controlling the fuel pressure before the high pressure pump 28 , a temperature sensor 38 for measuring the fuel temperature as well as a pressure sensor 40 for measuring the pressure in the fuel distributor rail 30 (rail pressure). The engine control unit 10 is connected via signal lines 42 to the sensors 38 , 40 and the injectors 24 of the fuel injection system 8 , to the air mass flow meter 14 and an actuator 44 for adjusting the throttle valve 18 , to the lambda probe 22 as well as to further, unspecified sensors and actuators, as, for example, a tachometer, respectively an accelerator pedal of the motor vehicle 2 . Sensor signals with information or data are evaluated in the engine control unit 10 . Said data comprise among other things the fresh air mass delivered into the cylinders 16 , which is measured by the air mass flow meter 14 , the combustion-air ratio measured by the lambda probe 22 , the rail pressure measured by the pressure sensor 40 as well as the fuel temperature measured by the temperature sensor 38 . The evaluated information or data together with an actuating signal from the accelerator pedal as well as with open-loop or closed-loop variables deposited in characteristic diagrams provide for the open-loop, respectively closed-loop, control of diverse parameters, which are significant for the combustion of fuel in the cylinders 16 . These parameters can comprise among other things the quantity of the fuel delivered into the cylinders 16 during one or a plurality of pilot injections, the point in time of the initiation of the pilot injection, respectively the pilot injections, the temporal interval between the pilot injections, respectively between a pilot injection, and the main injection, the height of the rail pressure supplied by the high pressure pump 28 , the position of the throttle valve 18 , the swirl of the injected fuel, the exhaust gas recirculation rate, i.e. the quantity of the exhaust gas recirculated out of the exhaust gas tract 20 into the cylinders, as well as the supercharging pressure of a super charger in the case of supercharged diesel engines. A portion of the information, which is transferred from the measuring devices, probes, respectively sensors 14 , 22 , 38 , 40 , to the engine control unit 10 , is furthermore used in the normal driving operation of the motor vehicle 2 in order to ascertain the ignitability of the fuel delivered from the fuel tank 4 into the fuel injection system 8 without necessitating the use of additional sensors or a special operating mode. Said ignitability can undergo considerable changes particularly when a change in the type of fuel is made, for example from diesel fuel to biodiesel fuel or vice versa. The ascertained ignitability of the fuel, which represents a measurement for its fuel quality and is usually expressed as the cetane index CCI or cetane number, is then used by the engine control unit 10 in order if required, i.e. when a change in the ascertained ignitability occurs, to appropriately change a portion of the previously mentioned parameters, respectively their nominal value characteristic diagrams, which are significant for the combustion in the cylinders, so that once again an optimal combustion is achieved. Because the cetane index can on the one hand be determined with the aid of empirical formulas, for example according to an especially simple formula: CCI=454.74−1.641416ερ+0.00077474ερ2−0.554ε t 50+97.803 log 2( t 50) whereby the cetane index CCI besides from being a function of the average boiling temperature t50 of the fuel in ° C., corrected to the ICAO Standard Atmosphere, is only a function of the density ρ of the fuel in kg/m 3 at a temperature of 15° C. and because on the other hand, the average boiling temperature t50 for all of the fuels, which are normally used in diesel engines, can be considered approximately as constant, it is possible to calculate the cetane index CCI with a sufficient degree of accuracy solely from the density ρ of the fuel. A method suited for this purpose is schematically depicted in FIG. 2 , wherein the density ρ of the fuel is calculated as an absolute value from the quotient of the mass m and the volume V of the fuel delivered during one injection into one of the cylinders 16 of the engine 6 . In the process, the mass m of the injected fuel is determined using a suitable software in the engine control unit 10 in step S 1 with the aid of a model calculation constructed for this purpose from the mass of the fresh air 46 delivered for combustion into the cylinder, which is measured by the air mass flow meter 14 , and from the combustion-air ratio 48 (air ratio λ) in the combustion exhaust gas being discharged from the cylinder 16 ; while in step S 2 , the injected fuel volume V, which is established by the rail pressure, as measured by sensor 40 , and by the activation duration 52 of the injectors, is likewise determined with the aid of a model calculation. In order to improve the accuracy of the method, the fuel temperature 54 measured by the sensor 38 as well as the backpressure 56 in the cylinder 16 deposited for the respective operating point of the engine 6 in characteristic diagrams of the engine control unit 10 are additionally taken into account in step S 2 . After the density ρ of the injected fuel has been calculated as the quotient of the mass m and the volume V in step S 3 , the cetane index of the fuel is then calculated in step S 4 from this density ρ, for example using the formula stated above. Because the fuel mass m, which was actually injected, can slowly change at constant activation parameters, as for example rail pressure 50 , activation duration 52 , fuel temperature 54 and backpressure 56 in the cylinder, as the result of drifts in the fuel injection system 8 over the service life of the engine 6 , respectively the motor vehicle 2 just as the air mass 46 measured by the air mass flow meter 14 as a result of a drift of the air mass flow meter 14 , it is possible that the absolute value of the density ρ and the cetane index determined from said absolute value can gradually deviate from the actual density ρ, respectively from the actual cetane index CCI, of the fuel. In order to compensate for this gradual deviation, respectively in order to take said deviation into account when ascertaining the density ρ, a reference value 58 for the mass m of the injected fuel can be determined in a preceding step S 0 for a new motor vehicle with a fuel with a known cetane index in the manner previously described. In step 5 while using the same fuel, this reference value 58 can then be compared with the fuel mass m, which was ascertained ( FIG. 2 ), in predetermined temporal intervals, for example during each service inspection of the motor vehicle 2 . This is done as shown in FIG. 3 in order to derive a correction value 60 for the calculation of the cetane index CCI. This correction value is then taken into account in step S 4 . On the contrary, rapid changes in the cetane index CCI, which was ascertained, suggest rather a change in the density ρ of the fuel, so that the accuracy of the method previously described can thereby also alternatively or additionally be improved, in that the determination of the fuel mass m is correlated with the fuelings of the tank 62 . Said change in the density ρ of the fuel can, for example, be suggested from a large change in the fill level of the fuel in the fuel tank 4 , from the opening of a fuel filler flap or from the calculated fuel consumption. As a further advantage of the method described, the fuel density ρ ascertained for the determination of the ignitability can also furthermore be taken into account as a multiplicative factor during the conversion of the fuel quantity to be fed into the injectors 24 into the activation duration 52 of the injectors 24 .

4y

[0001] This application is a continuation of U.S. patent application Ser. No. 13/186,296, filed Jul. 19, 2011, now U.S. Pat. No. 8,328,205, which is a continuation of U.S. patent application Ser. No. 12/772,413, filed May 3, 2010, now U.S. Pat. No. 7,984,913, which is a continuation of U.S. patent application Ser. No. 11/435,405, filed May 17, 2006, entitled “Locking Chuck,” now U.S. Pat. No. 7,708,288, which claims priority to U.S. Provisional Application No. 60/682,615, filed May 18, 2005, the entire disclosures of which are incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] The present invention relates generally to chucks for use with drills or with electric or pneumatic power drivers. More particularly, the present invention relates to a chuck of the keyless type which may be tightened or loosened by hand or actuation of the driver motor. [0003] Both hand and electric or pneumatic tool drivers are well known. Although twist drills are the most common tools on such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones, and other cutting or abrading tools. Since the tool shanks may be of varying diameter or of polygonal cross section, the device is usually provided with a chuck adjustable over a relatively wide range. The chuck may be attached to the driver by a threaded or tapered bore. [0004] A variety of chucks have been developed in the art. In an oblique jawed chuck, a chuck body includes three passageways disposed approximately 120° apart from each other. The passageways are configured so that their center lines meet at a point along the chuck axis forward of the chuck. The passageways constrain three jaws which are movable in the passageways to grip a cylindrical or polygonal tool shank displaced approximately along the chuck center axis. The chuck includes a nut that rotates about the chuck center and that engages threads on the jaws so that rotation of the nut moves the jaws in either direction within the passageways. The body is attached onto the drive shaft of a driver and is configured so that rotation of the body in one direction with respect to the nut forces the jaws into gripping relationship with the tool shank, while rotation in the opposite direction releases the gripping relationship. The chuck may be keyless if it is rotated by hand. Examples of such chucks are disclosed in U.S. Pat. Nos. 5,125,673 and 5,193,824, the entire disclosures of which are incorporated by reference herein. Various configurations of keyless chucks are known in the art and are desirable for a variety of applications. SUMMARY OF THE INVENTION [0005] The present invention recognizes and addresses the foregoing considerations, and others, of prior art constructions and methods. [0006] An embodiment of the present invention includes a chuck for use with a manual or powered driver having a rotatable drive shaft. The chuck includes a generally cylindrical body having a nose section and a tail section, the tail section being configured to rotate with the drive shaft and the nose section having an axial bore formed therein. A plurality of jaws are movably disposed with respect to said body in communication with said axial bore. A sleeve is rotatably mounted about the body in operative communication with the jaws so that rotation of the sleeve in a closing direction moves the jaws toward a longitudinal axis of the axial bore and rotation of the sleeve in an opening direction moves the jaws away from the longitudinal axis. A bearing has a first race adjacent the body, a second race adjacent the sleeve and at least one bearing element disposed between the first race and the second race. One of the first race and the second race define a ratchet and the other of the first race and the second race defines a pawl biased toward the ratchet, and a biasing element disposed between the pawl and the sleeve. The biasing element exerts a biasing force on said pawl toward said ratchet and wherein said ratchet and said pawl are configured so that when said pawl engages said ratchet, said ratchet and pawl prevent said second race from rotating in said opening direction with respect to said first race. [0007] Another embodiment of the invention provides a chuck for use with a manual or powered driver having a rotatable drive shaft. The chuck includes a generally cylindrical body having a nose section and a tail section, the tail section being configured to rotate with the drive shaft and the nose section having an axial bore formed therein. A plurality of passageways are formed therethrough and intersect the axial bore. A plurality of jaws are movably disposed in said passageways. A generally cylindrical first sleeve is rotatably mounted about the body and in operative communication with the jaws so that rotation of the first sleeve in a closing direction moves the jaws toward a longitudinal axis of the axial bore and rotation of the first sleeve in an opening direction moves the jaws away from the longitudinal axis. A bearing has a first race adjacent the body, a second race adjacent the first sleeve and a plurality of bearing elements disposed between the first race and the second race. The first race defines a ratchet, the second race defines a deflectable first pawl biased toward the ratchet, the ratchet and the first pawl being configured so that when the first pawl engages the ratchet, the ratchet and first pawl permit the second race to rotate in the closing direction with respect to the first race but prevent the second race from rotating in the opening direction with respect to the first race. A biasing element is disposed between the second race and the first sleeve, and the biasing element is configured to bias the first pawl toward said ratchet. [0008] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS [0009] A full and enabling disclosure of the present invention, including the best mode thereof to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, which makes reference to the accompanying figures, in which: [0010] FIG. 1 is a longitudinal view, partly in section, of a prior art chuck; [0011] FIG. 2 is an exploded view of a chuck as shown in FIG. 1 ; [0012] FIG. 3 is an exploded view of the bearing and nut of the chuck as shown in FIG. 1 ; [0013] FIG. 4A is a partial perspective view of the sleeve of the chuck as shown in FIG. 1 ; [0014] FIG. 4B is a partial perspective view of the bearing and sleeve of the chuck as shown in FIG. 1 ; [0015] FIG. 4C is a partial perspective view of the bearing and sleeve of the chuck as shown in FIG. 1 ; [0016] FIG. 5 is a perspective view of a chuck jaw of the chuck as shown in FIG. 1 ; [0017] FIG. 6 is an exploded view of a chuck in accordance with an embodiment of the present invention; [0018] FIG. 7 is a longitudinal view, in section, of a chuck as shown in FIG. 6 ; and [0019] FIG. 8 is an exploded view of a chuck in accordance with an embodiment of the present invention. [0020] Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0021] Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the present disclosure. [0022] Referring to FIGS. 1 and 2 , a prior art chuck 10 includes a body 14 , a nut 16 , a front sleeve 18 , a nose piece 20 and a plurality of jaws 22 . Body 14 is generally cylindrical in shape and comprises a nose or forward section 24 and a tail or rearward section 26 . Nose section 24 has a front face 28 transverse to the longitudinal center axis 30 of body 14 and a tapered surface 32 at its forward end. The nose section defines an axial bore 34 that is dimensioned somewhat larger than the largest tool shank that the tool is designed to accommodate. A threaded bore 36 is formed in tail section 26 and is of a standard size to mate with the drive shaft of a powered or hand driver (not shown). The bores 34 , 36 may communicate at a central region 38 of body 14 . While a threaded bore 36 is illustrated, such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft. Furthermore, body 14 may be formed integrally with the drive shaft. [0023] Body 14 defines three passageways 40 to accommodate the three jaws. Each jaw is separated from the adjacent jaw by an arc of approximately 120°. The axes of passageways 40 and jaws 22 are angled with respect to the chuck center axis 30 such that each passageway axis travels through axial bore 34 and intersects axis 30 at a common point ahead of the chuck body. The jaws form a grip that moves radially toward and away from the chuck axis to grip a tool, and each jaw 22 has a tool engaging face 42 generally parallel to the axis of chuck body 14 . Threads 44 , formed on the jaw's opposite or outer surface, may be constructed in any suitable type and pitch. As shown in FIG. 5 , each jaw 22 may be formed with a carbide insert 112 pressed into its tool engaging surface. [0024] As illustrated in FIGS. 1 and 2 , body 14 includes a thrust ring 46 that, preferably, may be integral with the body. It should be understood, however, that thrust ring 46 and body 14 may be separate components. Thrust ring 46 includes a plurality of jaw guideways 48 formed around its circumference to permit retraction of jaws 22 therethrough and also includes a ledge portion 50 to receive a bearing assembly as described below. [0025] Body tail section 26 includes a knurled surface 54 that receives an optional rear sleeve 12 in a press fit at 55 . Rear sleeve 12 could also be retained by press fit without knurling, by use of a key or by crimping, staking, riveting, threading or any other suitable securing mechanism. Further, the chuck may be constructed with a single sleeve having no rear sleeve. [0026] Nose piece 20 retains nut 16 against forward axial movement. The nose piece is press fit to body nose section 24 . It should be understood, however, that other methods of axially securing the nut on the body may be used. For example, the nut may be a two-piece nut held on the body within a circumferential groove on the outer circumference of the body. Nose piece 20 may be coated with a non-ferrous metallic coating to prevent rust and to enhance its appearance. Examples of suitable coatings include zinc or nickel, although it should be appreciated that any suitable coating could be utilized. [0027] The outer circumferential surface of front sleeve 18 may be knurled or may be provided with longitudinal ribs 77 or other protrusions to enable the operator to grip it securely. In like manner, the circumferential surface of rear sleeve 12 , if employed, may be knurled or ribbed as at 79 if desired. [0028] Front sleeve 18 is secured from movement in the forward axial direction by an annular shoulder 91 on nose piece 20 . A frustoconical section 95 at the rearward end of the nose piece facilitates movement of jaws 22 within the chuck. [0029] The front and rear sleeves may be molded or otherwise fabricated from a structural plastic such as polycarbonate, a filled polypropylene, for example a glass filled polypropylene, or a blend of structural plastic materials. Other composite materials such as, for example, graphite filled polymerics may also be suitable in certain environments. As should be appreciated by one skilled in the art, the materials from which the chuck is fabricated will depend on the end use of the chuck. [0030] Nut 16 has threads 56 for mating with jaw threads 44 . Nut 16 is positioned about the body in engagement with the jaw threads so that when the nut is rotated with respect to body 14 , the jaws will be advanced or retracted depending on the nut's rotational direction. [0031] As illustrated in FIG. 3 , the nut's forward axial face includes recesses 62 that receive respective drive dogs 64 ( FIG. 2 ) extending from the inner surface of front sleeve 18 . The angular width of the drive dogs is less than that of the recesses, resulting in a slight range of relative rotational movement, for example between 6° and 10° between the nut and the front sleeve. [0032] Nut 16 also defines a plurality of grooves formed as flats 68 about the nut's outer circumference. Flats 68 receive respective tabs 70 extending forward from an inner race 72 of a bearing assembly 74 . The engagement of tabs 70 and flats 68 rotationally fix the inner race to the nut, although it should be understood that there may be a slight rotational tolerance between the two. [0033] Inner race 72 receives a plurality of bearing elements, in this case bearing balls 76 , disposed between it and an outer race 78 seated on thrust ring ledge 50 ( FIG. 1 ). Outer race 78 is rotationally fixed to body 14 by a plurality of tabs 80 received in corresponding grooves 82 in the thrust ring ledge. In an embodiment of the invention described herein, outer race 78 is not rotationally fixed with respect to the thrust ring, and tabs 80 and grooves 82 are therefore omitted. In such embodiment, outer race 78 can rotate with respect to the body until the jaws close onto a tool shank, at which point rearward force from the nut through the bearing gives rise to friction between outer race 78 and the thrust ring that holds the outer race in place rotationally on the body. [0034] Returning to the prior art chuck in FIGS. 1 through 3 , outer race 78 also includes a ratchet formed by a plurality of sawtooth-shaped teeth 84 disposed about the inner circumferential surface of the outer race. A first pawl 86 extends from one side of each tab 70 . First pawl 86 is biased radially outward from the inner race, thereby urging a distal end 88 of each first pawl 86 towards the outer race ratchet. [0035] Each tooth 84 has a first side with a slope approaching 90 ° with the periphery of the outer race. A second side of each tooth 84 has a lesser slope. First pawl 86 is deflectable and is generally disposed in alignment with the slope of the second side. Thus, rotation of inner race 72 in a closing direction 90 with respect to outer race 78 moves first pawl distal ends 88 repeatedly over teeth 84 , causing a clicking sound each as end 88 falls against each subsequent tooth second side. This configuration of teeth and first pawls 86 , however, prevents the inner race's rotation in an opposite opening direction 92 . Application of rotational force to the inner race in this direction forces distal ends 88 into the steep-sloped first sides of teeth 84 . Since pawl 86 is generally perpendicular to the first sides, it does not deflect inward to permit rotation. As discussed below, direction 90 corresponds to the chuck's closing direction, while direction 92 corresponds to the chuck's opening direction. Accordingly, when pawls 86 engage ratchet teeth 84 , the teeth permit the inner race's movement in the chuck's closing direction 90 but prevent its movement in the opening direction 92 . [0036] A second deflectable pawl 94 extends from the other side of each tab 70 . Like first pawls 86 , each second pawl 94 is biased radially outward. Unlike first pawls 86 , however, second pawls 94 do not engage the outer race ratchet. [0037] First and second pawls 86 and 94 include tabs 96 and 98 , respectively, at their distal ends. Referring also to FIG. 4A , an inner circumferential surface of sleeve 18 defines first and second recesses 100 and 102 . During the chuck's operation, each tab 98 is received in one of these recesses, depending on the sleeve's rotational position with respect to the nut as discussed in more detail below. The sleeve also defines a third recess 104 and a cam surface 106 . Also depending on the sleeve's rotational position, each tab 96 is received either by the cam surface or by recess 104 . The sleeve includes a pair of recesses 100 , 102 for each tab 98 and a recess 104 and cam surface 106 for each tab 96 . [0038] FIG. 4C illustrates the disposition of pawls 86 and 94 when sleeve 18 is in a first of two positions with respect to nut 16 , while FIG. 4B illustrates these components when the sleeve is in a second position with respect to the nut. For ease of illustration, both figures omit the nut. However, referring to FIG. 2 and to the sleeve's second position as shown in FIG. 4B , each drive dog 64 is disposed against or adjacent to a side 108 of the gap 62 in which it is received. Each of the sleeve's recesses 102 receives a tab 98 of a second pawl 94 , and each recess 104 receives a tab 96 of a first pawl 86 . Accordingly, the distal end 88 of each first pawl 86 engages ratchet teeth 84 , and inner race 72 can rotate only in direction 90 with respect to outer race 78 . [0039] Referring now to FIG. 4C , when front sleeve 18 moves in opening direction 92 with respect to outer race 78 , each tab 98 moves out of its recess 102 and into its recess 100 , as indicated by arrow 107 . Each tab 96 rides up and out of its recess 104 onto its cam surface 106 , as indicated by arrow 110 . As indicated by arrow 113 , this pushes each deflectable tab 86 radially inward, thereby disengaging distal ends 88 from ratchet teeth 84 . Thus, the inner race is free to rotate with respect to the outer race. [0040] As described in more detail below, when sleeve 18 rotates in opening direction 92 so that the inner race moves from the position shown in FIG. 4B to the position shown in FIG. 4C , drive dogs 64 move within groove 62 of nut 16 ( FIG. 2 ) so that each drive dog is against or immediately adjacent to a side 111 of the groove. [0041] In operation and referring to FIGS. 2 , 3 , 4 B and 4 C, when the chuck is between the fully opened and the fully closed positions, nut grooves 62 receive drive dogs 64 so that the drive dogs are adjacent groove sides 111 Inner race 72 is disposed with respect to outer race 78 so that tabs 96 and 98 are received by cam surface 106 and recess 100 , respectively. That is, sleeve 18 is in the first position with respect to the nut, as shown in FIG. 4C . In this condition, tabs 98 and recesses 100 rotationally fix inner race 72 to sleeve 18 . Since inner race 72 is rotationally fixed to nut 16 by tabs 70 and flats 68 , an operator rotating sleeve 18 rotationally drives the nut through the bearing's inner race 72 , thereby opening or closing the jaws. When the operator rotates the sleeve, the bearing inner race and the nut in the closing direction (indicated by arrow 90 in FIG. 4C ) to the point that the jaws tighten onto a tool shank, the nut is urged rearward up the jaw threads, thereby pushing the nut against inner race 72 , bearing elements 76 , outer race 78 , and thrust ring 46 . The rearward force creates a frictional lock between the nut and inner race 72 that further holds the inner race and the nut in place rotationally with respect to the body. [0042] The wedge between the nut threads and jaw threads increasingly resists the nut's rotation. When the operator continues to rotate sleeve 18 and the resistance overcomes the hold provided by tabs 98 in recesses 100 , sleeve 18 rotates with respect to nut 16 and inner bearing race 72 . This moves drive dogs 64 from sides 111 of grooves 62 to sides 108 and pushes tabs 98 out of recesses 100 into recesses 102 . Simultaneously, cam surfaces 106 rotate away from tabs 96 so that the tabs are released into recesses 104 , thereby engaging distal ends 88 of first pawls 86 with ratchet teeth 84 , as shown in FIG. 4B . At this point, inner race 72 , and therefore nut 16 , is rotationally locked to outer race 78 , and therefore body 14 , against rotation in the chuck's opening direction. That is, the nut is rotationally locked to the chuck body in the opening direction. Since the nut's rotation with respect to the body is necessary to open the chuck, this prevents inadvertent opening during use. [0043] Inner race 72 , and therefore nut 16 , may, however, still rotate with respect to outer race 78 , and therefore body 14 , in the chuck's closing direction. During such rotation, sleeve 18 drives nut 16 through drive dogs 64 against groove sides 108 , as well as through inner race 72 . This continues to tighten the chuck and as described above and produces a clicking sound to notify the operator that the chuck is in a fully tightened position. [0044] To open the chuck, the operator rotates sleeve 18 in opening direction 92 . Sleeve 18 transfers this torque to inner race 72 at the engagement of tabs 96 and 98 in recesses 104 and 102 , respectively. Because pawls 86 engage outer race 78 , which is rotationally fixed to the body, the inner race cannot rotate with the sleeve. Thus, upon application of sufficient torque in opening direction 92 , sleeve 18 moves with respect to the inner race and the nut. This moves tab 96 back up onto cam surface 106 , thereby disengaging first pawl 86 from ratchet teeth 84 . Tab 98 moves from second recess 102 into first recess 100 , and drive dogs 64 move from sides 108 to sides 111 of grooves 62 . Thus, the sleeve moves to its first position with respect to the nut, as shown in FIG. 4C , and the inner race and nut are free to rotate with respect to the outer race and chuck body. Accordingly, further rotation of sleeve 18 in the opening direction moves jaws 22 away from the chuck axis, thereby opening the chuck. [0045] The pawls and ratchet may be formed in any suitable configuration. Furthermore, the chuck may be realized in a variety of configurations whereby a bearing having a ratchet configuration is disposed between a sleeve, for example a nut or other suitable configuration, and the chuck body. For example, a chuck may include a body, a nut that is rotationally fixed to and axially movable with respect to the body, and an outer sleeve that threadedly engages the nut so that rotation of the sleeve moves the nut axially on the body. The jaws may be axially fixed to the nut and received in body passageways so that the nut's axial movement drives the jaws towards and away from the chuck's axis. In this configuration, an outer sleeve may be permitted to rotate over a limited angular distance with respect to a second sleeve. A bearing including a ratchet configuration as discussed above may be disposed between the second sleeve and the chuck body. Depending on the chuck's configuration, the pawls and ratchet may be interchanged as appropriate. [0046] FIGS. 6 and 7 illustrate an embodiment of a chuck 11 of the present invention having a body 14 , a nut 16 , a front sleeve 18 (comprised of a metal outer part 19 , a polymer inner part 21 and a metal insert 17 ), a nose piece 20 and a plurality of jaws 22 . An embodiment shown in FIG. 8 has a front sleeve 18 comprised of a metal outer part 19 and a polymer inner part 21 without a metal insert. Body 14 , which is constructed substantially the same as the body described above with respect to FIG. 2 , is generally cylindrical in shape and comprises a nose or forward section 24 and a tail or rearward section 26 . Nose section 24 has a forward end 32 that tapers from a smooth cylindrical outer circumference to a front face transverse to the longitudinal center axis of body 14 . The nose section defines an axial bore 34 that is dimensioned somewhat larger than the largest tool shank the tool is designed to accommodate. A threaded bore 36 is formed in tail section 26 and is of a standard size to mate with the drive shaft of a powered or hand driver (not shown). Front bore 34 and rear bore 36 may communicate at a central region 38 of body 14 . While a threaded bore 36 is illustrated, such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft. Furthermore, body 14 may be formed integrally with the drive shaft. A rear ring 37 is also formed integrally with body 14 and defines a plurality of guideways 39 to accommodate jaws 22 in their rearward positions. [0047] Body 14 defines three passageways 40 to accommodate the three jaws. Each jaw is separated from the adjacent jaw by an arc of approximately 120°. The axes of the jaw passageways and jaws 22 are angled with respect to the chuck center axis such that each passageway axis travels through the forward axial bore in the body and intersects the chuck axis at a common point. The jaws form a grip that moves radially toward and away from the chuck axis to grip a tool, and each jaw 22 has a tool engaging face 42 generally parallel to the axis of chuck body 14 . Threads 44 , formed on each jaw's opposite or outer surface, may be constructed in any suitable type and pitch. As also indicated in FIG. 5 , each jaw 22 may be formed with one or more carbide inserts 112 pressed into its tool engaging surface. [0048] As illustrated in FIGS. 6 through 8 , body 14 includes a thrust ring 46 that, in a preferred embodiment, may be integral with the body. It should be understood, however, that thrust ring 46 and body 14 may be separate components. Thrust ring 46 includes a plurality of jaw guideways 48 formed around its circumference to permit retraction of jaws 22 therethrough and includes a ledge portion 50 to receive a bearing assembly as described below. [0049] Body tail section 26 includes a knurled surface 54 that receives a dust cover 13 in a press fit. Dust cover 13 could also be retained by press fit without knurling, by use of a key or by crimping, staking, riveting, threading or any other suitable securing mechanism. Further, the chuck may be constructed with two hand-actuatable sleeves, as shown in FIGS. 1 and 2 . Nose piece 20 is press fit to body nose section 24 and retains nut 16 against forward axial movement. Nose piece 20 may be coated with a non-ferrous metallic coating to prevent rust and to enhance its appearance. Examples of suitable coatings include zinc or nickel, although it should be appreciated that any suitable coating could be utilized. It should also be understood that other methods of axially securing the nut on the body may be used. For example, the nut may be a two-piece nut held on the body within a circumferential groove on the body's outer circumference. [0050] Front sleeve 18 is secured from movement in the forward axial direction by an annular shoulder 91 on nose piece 20 . A frustoconical section 95 at the rearward end of the nose piece facilitates movement of jaws 22 within the chuck. [0051] The outer circumferential surface of front sleeve outer part 19 may knurled or may be provided with longitudinal ribs or other protrusions to enable the operator to grip it securely. Outer front sleeve part 19 and metal insert 17 ( FIGS. 6 and 7 ) may be deep drawn or otherwise fabricated from steel or other metal material such as Zamac (zinc aluminum metal alloy casting). The metal insert is preferably steel hardened to an HRC 43-51 Inner sleeve part 21 may be molded or otherwise fabricated from a structural plastic such as polycarbonate, a filled polypropylene, for example a glass filled polypropylene, or a blend of structural plastic materials. Other composite materials such as, for example, graphite filled polymerics may also be suitable in certain environments. Metal insert 17 may be pressed or otherwise assembled inside inner sleeve part 21 in close conformity so that the inner sleeve part retains the metal insert. In one preferred embodiment, inner sleeve part 21 is molded about the metal insert. As should be appreciated by one skilled in the art, the materials from which the chuck of the present invention is fabricated will depend upon the end use of the chuck, and the above materials are provided by way of example only. [0052] Generally, the outer surface of inner part 21 conforms to the inner surface of outer part 19 . However, polymer inner part 21 defines a plurality of flanges 23 that extend forward from the main portion of the inner sleeve part. Flanges 23 include front edges 25 that extend radially outward to thereby define a groove 27 between edges 25 and the front edge of the inner sleeve part's main portion. The segmented arrangement of flanges 23 allows the flanges to flex inward as the outer part is assembled over the inner part. A front edge 29 of outer sleeve part 19 extends radially inward and is notched to receive flanges 23 . Thus, at the notches, front edge 29 extends radially inward into groove 27 , while flanges 23 extend through the notches. Thus, groove 27 retains outer sleeve part 19 in the axially forward and rearward directions between the tabs' front edges 25 and the forward edge of the main portion of sleeve inner part 21 . Sleeve outer part 19 rotationally drives sleeve inner part 21 through the interengagement of front edge 29 and flanges 23 and through a plurality of spaced-apart dogs (not shown) extending radially inward from the outer sleeve part's inner circumferential surface into corresponding notches 31 in the front outer surface of inner sleeve part 21 . It should be understood that the two-part sleeve shown in FIGS. 6 through 8 may be replaced with a unitarily-formed polymer sleeve such as shown in FIGS. 1 and 2 . [0053] Nut 16 has threads 56 for mating with jaw threads 44 and is positioned about the body in engagement with the jaw threads so that when the nut is rotated with respect to body 14 , the jaws will be advanced or retracted depending on the nut's rotational direction. [0054] The nut's forward axial face includes recesses 62 that receive respective drive dogs 64 extending from the inner surface of inner sleeve part 21 . Recesses 62 and drive dogs 64 are constructed as described above with respect to FIG. 2 . Similarly, the inner surface of metal insert 17 (or, in the embodiment of FIG. 8 , sleeve inner part 21 ) defines recesses 100 , 102 and 104 and a cam surface 106 as is described above with respect to the inner surface of sleeve 18 in FIGS. 1 and 2 . For the purpose of clarity, the positions of recesses 100 , 102 and 104 and cam surface 106 in inner sleeve part 21 behind insert 17 are indicated in FIG. 6 as recesses 100 a, 102 a, and 104 a, and cam surface 106 a. [0055] Nut 16 also defines a plurality of grooves, formed as flats 68 about the nut's outer circumference, that receive respective tabs 70 extending forward from an inner race 72 of a bearing assembly 74 . The engagement of tabs 70 and flats 68 rotationally fix the inner race to the nut, although it should be understood that there may be a slight rotational tolerance between the two. [0056] Inner race 72 receives a plurality of bearing elements, in this case bearing balls 76 , disposed between it and an outer race 78 seated on thrust ring ledge 50 . Outer race 78 is rotationally fixed to body 14 by a plurality of tabs 80 received in corresponding grooves 82 in the thrust ring ledge, as is described above with respect to FIGS. 1 and 2 . In an alternate embodiment, outer race 78 is not rotationally fixed with respect to the thrust ring, and the tabs and grooves are therefore omitted. In such alternate embodiment, outer race 78 can rotate with respect to the body until the jaws close onto a tool shank, at which point rearward force from the nut through the bearing gives rise to friction between outer race 78 and thrust ring ledge 50 that ultimately holds the outer race in place rotationally on the body. [0057] As discussed above with respect to outer race 78 in FIG. 2 , outer races 78 in FIGS. 6 through 8 include a ratchet. In the illustrated embodiments, the ratchet is formed by a plurality of saw tooth-shaped teeth 84 disposed about the outer race's inner circumferential surface. A first pawl 86 extends from one side of each tab 70 and is biased radially outward from the inner race, thereby urging a distal end 88 of each first pawl 86 toward the outer race ratchet. Teeth 84 are formed, and interact with pawl distal end 88 , as described above with respect to the corresponding components of FIGS. 1 through 4 . [0058] A second deflectable pawl 94 extends from the other side of each tab 70 . Like first pawls 86 , each second pawl 94 is biased radially outward. Unlike first pawls 86 , second pawls 94 do not engage the outer race ratchet. Pawls 86 and 94 are constructed identically to pawls 86 and 94 as described above with respect to FIGS. 1 and 2 . First and second pawls 86 and 94 include tabs 96 and 98 , respectively, at their distal ends that interact with recesses 100 , 102 and 104 , and cam surface 106 , in the same manner as described above. Moreover, the operation of the chucks shown in FIGS. 6 through 8 , with respect to opening, closing and locking by the interaction of pawls 86 and 94 with the inner surface of sleeve 18 (more particularly, the inner surface of metal insert 17 in FIGS. 6 and 7 and inner sleeve part 21 in FIG. 8 ), is the same as the operation of chuck 10 shown in FIGS. 1 through 4 , and is therefore not repeated. [0059] In drill chuck 10 as shown in FIGS. 1 and 2 , nut 16 defines a smooth cylindrical shoulder 130 extending in the axial direction between a curved surface 132 and a transverse annular shoulder 134 extending between shoulder 130 and an annular shoulder 136 upon which flats 68 are defined. In the embodiments of the present invention illustrated in FIGS. 6 through 8 , a resilient structure is disposed between shoulder 130 and first and second pawls 86 and 94 in sufficient volume and/or geometry so that the resilient intermediate structure increases the pawls' radially outward bias to thereby dampen vibrations that arise from the chucks' usage with a given power driver and that otherwise tend to dislodge the pawls from their positions with respect to the outer race and sleeve, as shown in FIGS. 4B and 4C . [0060] As shown in FIGS. 6 through 8 , for example, a groove 138 is formed in shoulder 130 so that, when nut 16 is assembled onto body 14 , groove 138 is defined in a plane perpendicular to the chuck axis and receives an O-ring 140 . In one preferred embodiment, O-ring 140 is made of VITON, a fluoroelastomer manufactured by DuPont Dow Elastomers LLC of Wilmington, Del., and has an axial width of about 1/16 inches, an inner diameter of about 1.000 inches and an outer diameter of about 1.125 inches. [0061] The diameter defined by shoulder 130 on either side of groove 138 is approximately 1.244 inches, while the diameter of a circle defined by the trough of groove 138 is approximately 1.200 inches. Thus, O-ring 140 stretches when installed into groove 138 , and its outer diameter becomes approximately 1.325 inches. A radius defined from the axis of chuck body 14 to any of pawls 86 and 94 in their positions as shown in FIG. 4B is approximately 0.651 inches, corresponding to a diameter of 1.302 inches. First and second pawls 86 and 94 thereby compress O-ring 140 , which, due to its resilience, responsively applies a radially outward force to the pawls. This radially outward force provides a secondary radially outward bias to the pawls that supplements the pawls' inherent radially outward bias and increases the pawls' tendency to remain seated in either of their two above-described positions during the power driver's operation. That is, O-ring 140 increases resistance to vibrational forces that may tend to push the pawls radially inward out of their respective grooves defined in the inner diameter of the sleeve, thereby inhibiting the chuck from opening or closing during use. [0062] It will also be recognized that the increased radially outward bias increases the force necessary to be applied by the user in moving the sleeve between the locking mechanism's two operative positions. Thus, it should be understood that the materials and geometry of O-ring 140 may be selected to dampen vibrations in a power driver having a given power rating while still permitting effective manual operation by the user. For example, it is expected that a drill chuck as described above with respect to FIGS. 6 through 8 (where O-ring 140 has a Shore A hardness from 60 to 80 and where outer race 78 is rotationally fixed to body 14 by tabs 80 received in grooves 82 in the thrust ring) will resist vibrations generated by a model GSB 18-2 RE 750 watt AC impact drill, manufactured by BOSCH Tool Corporation of Farmington Hills, Mich., such that the chuck does not undesirably open or over tighten. [0063] In another preferred embodiment, groove 138 is formed into shoulder 130 in a square cross section, and O-ring 140 is formed in a correspondingly square cross section. The dimensions of the nut and O-ring otherwise remain the same. [0064] It should also be understood that various materials may be used to construct O-ring 140 . For example, materials include various suitable elastomers such as acrylonitrile-butadiene (NBR, buna N, or nitrile rubber), chloroprene rubber (CR, or neoprene), polyacrilic rubber, silicone rubber, butyl rubber (ITR), styrene-butadiene (SBR, or buna S rubber), chlorosulfonated polyethelene (CSM, commercially available under the name HYPALON), or polysulfide rubber (T, or thiokol polymer) or thermoplastics such as suitable fluorocarbons (e.g. Teflon TFE or FEP), impact grade polystyrenes comprising polystyrene and rubber, and polyamide resins (nylon). O-rings made from commercially available materials such as the fluoroelastomers and perfluoroelastomers VITON, KALREZ, SIMRIZ, CHEMRAZ and AFLAS, and HYPALON (chlorosulfonated polyethylene), are available from Marco Rubber & Plastic Products, Inc. of North Andover, Mass. [0065] The shape of O-ring 140 may vary as desired. For example, O-ring 140 maybe molded into a shape that conforms at its inner diameter to the outer surface of shoulder 130 (with or without a groove 138 ) and that conforms at its outer circumference to the surfaces of pawls 86 and 94 that face the nut. The molded O-ring is preferably made by compression molding and can be formed from any of the above-described materials suitable for compression or injection molding. The O-ring can be molded as a separate component or can be molded directly around the nut. [0066] To determine whether a given dampening structure, whether an O-ring of a selected material and geometry or any other selected resilient device, will sufficiently dampen vibrations for a given chuck configuration on a given driver, the structure may be assembled on a chuck and tested with the driver. Referring to the drill chuck as shown in FIGS. 6 through 8 , for example, the chuck may be assembled and operated with a drill bit shank so that jaws 22 securely grip the tool shank. An alignment mark is then made axially along the outer surface of sleeve 18 , nose piece 20 and the tool shank so that the mark lies on the sleeve, nose piece and tool shank in a plane that includes the axis of chuck body 14 . The driver/chuck/bit is then operated to drill holes in selected materials, for example steel, concrete, diorite and wood. A hammer function may be applied while drilling in concrete and diorite. After each hole is drilled, or after each of a certain number of holes is drilled, the alignment of the marks on the sleeve, nose piece and bit is checked to determine whether the chuck has undesirably opened or over tightened. [0067] The construction of the pawls and ratchet teeth contribute to the resistance of the locking mechanism to vibrations and, consequently, to the degree to which a supplemental outward bias is desirable. For example, the depth of pawl teeth 84 constructed as described above contributes to the effectiveness of the primary outward bias and, in a preferred embodiment as shown in FIGS. 6 through 8 , is approximately 14/1000 inches. Further, pawls 86 and 94 are preferably constructed with sufficient stiffness so that when the inner and outer races are assembled together on the nut (but apart from the chuck body and jaws), and the nut and inner race are rotationally secured, at least an about 2 in-lb torque is required to ratchet pawl end 88 over teeth 84 , and in a preferred embodiment, the torque required is within a range of about 2 to about 3 in-lbs. In the example described below in which an about 0.7 gram layer of RTV sealant is disposed between the nut and the pawls, the torque required to ratchet the pawl over the ratchet teeth is within a range of about 4 in-lbs to 5 in-lbs. [0068] It should also be understood that mechanisms other than O-rings may be used to apply additional bias to the pawls. In another preferred embodiment, for example, groove 138 in shoulder 130 may be omitted, so that shoulder 130 has a smooth surface as in FIGS. 1 and 2 , and a spring band is received over the shoulder. The spring band is comprised of a central annular ring that may fit loosely over or be pressed to shoulder 130 . A number of spring arms extend outward from, and are biased radially away from, the central band. There is one spring arm for each pawl 86 and 94 , and a distal end of each spring arm engages its corresponding pawl to thereby apply a supplemental radially outward bias to the pawl. Particularly where the spring band's central ring fits loosely about the nut, the distal end of each spring arm may define tabs shaped correspondingly to tabs 96 and 98 (see FIG. 3 ) so that the spring arm tabs are received in tabs 96 and 98 to thereby rotationally orient the spring band with respect to inner race 72 . [0069] In a further preferred embodiment, shoulder 130 is again smooth, and O-ring 140 is replaced by a layer of silicone RTV (room-temperature vulcanized) rubber, for example 732 multi-purpose silicone RTV sealant made by Dow Corning Corporation and available from IDG Corporation of Belmont, N.C. The RTV sealant may be applied manually or automatically. For a construction as shown in FIGS. 6 through 8 , in which six pawls 86 and 94 are used, six nozzles may be arranged in a pattern so that when the nozzles are brought to a position proximate shoulder 130 , the nozzles deposit dots of RTV sealant at positions on the shoulder corresponding to the opposing pawls. [0070] In a preferred embodiment in which shoulder 130 defines a diameter of approximately 1.244 inches, a total of approximately 0.7 grams of RTV sealant is disposed on the shoulder. It should be understood, however, that the amount of RTV sealant may vary as desired, with the lower end of the desirable range being the point at which the RTV sealant fails to provide sufficient resilient force for a given chuck and driver, and the upper end of the desirable range being the point at which RTV sealant extends beyond an operative space between shoulder 130 and the pawls and thereby fails to contribute to the additional bias force. In the arrangement (with a smooth shoulder 130 ) as described above with respect to FIGS. 1 and 2 , a range of 0.4 grams to 1.6 grams was found to be desirable. Using a chuck as in FIGS. 6 through 8 with the method described above, a 0.7 gram layer of RTV sealant was found to dampen vibrations in a model GSB 18-2 RE 750 watt AC impact drill and a model GSB 20-2 RCE 1010 watt AC impact drill manufactured by BOSCH Tool Corporation of Farmington Hills, Mich. [0071] While one or more preferred embodiments of the present invention have been described above, it should be understood that any and all equivalent realizations of the present invention are included within the scope and spirit thereof. Thus, the depicted embodiments are presented by way of example only and are not intended as limitations on the present invention. It should be understood that aspects of the various one or more embodiments may be interchanged both in whole or in part. Therefore, it is contemplated that any and all such embodiments are included in the present invention as may be fall within the literal or equivalent scope of the present disclosure.

4y

BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to a method for producing retroreflective sheeting useful for marking or the like of signs such as road signs and construction signs; number plates of vehicles such as motorcars and motorcycles; materials for safety such as clothes and life jackets; signboards, etc. 2. Description of the Prior Art Retroreflective sheeting which retroreflects light toward the light source have hitherto been well known, and are widely utilized in such utilization fields as mentioned above utilizing their retroreflectivity. Among them, encapsulated lense-type retroreflective sheeting, whose light-retroreflective performance is enhanced by utilizing the low refractive index of gas and forming a gaseous layer between a light-transmittable protective film and retroreflective glass beads, is finding yearly increasing utility because of their excellent light-retroreflective ability. Generally, the structure of encapsulated lense-type retroreflective sheeting is composed of, as shown in FIG. 1, a light-transmittable protective film (1) and a support film (2) facing each other through a narrow gaseous layer, and a continuous, linear binding wall (3) formed by partially, thermally fusing and deforming the support film for binding both of them, and retroreflective glass beads (6), whose almost lower hemispherical surface is covered with a vapor-deposited metal film (5), are embedded in the support film in a large number of sealed, small compartment cells (4) surrounded by the binding wall, in such a manner that they form a substantial monolayer and the non-reflecting part of the glass beads is exposed. As to such encapsulated lense-type retroreflective sheeting, the height of its light-retroreflective ability is desired as the most important function, and, in addition, such good weather resistance that even when it is used in a severe condition such as outdoor use, their excellent retroreflective performance can be maintained over a long period of time, the vividness of the color of the retroreflective sheeting for heightening visibility, etc. are also required as important functions. The lowering of retroreflective performance occurring when encapsulated lense-type retroreflective sheeting is used outdoors for a long period is caused, in almost all the cases, by that the sealed, small compartment cells are destroyed, and rainwater, etc. invade therein. Retroreflective performance is lowered, for example, by that the gastightness of the sealed, small compartment cells is lost, because of cracks of the protective film due to the repeats of the expansion and contraction of the gas in the sealed, small compartment cells accompanying the change of outdoor temperature, and the repeats of the expansion and contraction of the metal plate, etc. on which the retroreflective sheeting is stuck also accompanying the change of out-door temperature, etc.; adhesion destruction at the interface between the protective film and the binding wall; the destruction of the binding wall itself or the destruction of the support film itself, or the like, rainwater, etc. invade in the cells, and as a result, the refractive index condition in the cells, which is an important factor for the retroreflective performance, changes, or the vapor-deposited metal film, which is a light-reflecting film, etc. are deteriorated to lose the light reflective ability, etc. Among them, the binding wall binding the protective film and the support film tend to be most easily influenced by distortion and most easily destroyed, because of their construction, and, in fact, many cases of the deterioration of retroreflective sheeting and the lowering of retroreflective performance occur due to the destruction of the binding wall. Therefore, for improving the weather resistance of retroreflective sheeting, it is most important to form a binding wall having excellent strength. Various attempts have hitherto been made, for improving the strength of the binding wall, and, for example, it is proposed in Japanese Patent Publication No. 13561/1986 (=U.S. Pat. No. 4,025,159; GB-B-1,547,043) to heighten the strength of the binding wall by thermally fusing and deforming the support film to form binding wall (binding part tissue), and then irradiating the binding wall with a radiation to crosslink the binding wall, and a typical example of the production method is described. The typical example of the method for producing encapsulated-type retroreflective sheeting, disclosed in Japanese Patent Publication No. 13561/1986, is as follows, as described in Example 1 therein. First, a radiation-curable composition is applied onto a temporary support (composed of a polyethylene layer and paper) having glass beads embedded part of each of them in the polyethylene layer which is a thermoplastic polymer, and having vapor-deposited metallic aluminum on the top surface thereof, and dried to form a support layer. As illustrated in Example 10 of the said Japanese Patent Publication, it is also possible to previously form a support layer on a film such as a polyethylene terephthalate film, superpose it on the glass beads in the temporary support, and press the superposed matter. Then, a polyethylene terephthalate film having a pressure sensitive adhesive layer is laminated and stuck on the support layer, and then the temporary support is peeled to give a substrate sheet. A polymethyl methacrylate film, which will be a protective (covering) film, is superposed on the glass beads side of this substrate sheet, and the support layer is partially thermally fused and deformed to laminate and bind the protective film and the support layer as a binding wall (binding part) having network tissue. Then, the resultant sheeting is irradiated with a radiation to cure the binding part, whereby encapsulated-type (cellular) retroreflective sheeting is produced. However, since, in the above-proposed method, no care is made on preventing the vapor-deposited metal film formed on the part other than the glass beads on the temporary support, from being transferred on the support film, the vapor-deposited metal film transferred from the temporary support remains on the support film surface between the glass beads, and therefore, many broken pieces of the vapor-deposited metal film remain in the binding wall obtained by thermally fusing and deforming this support film. Thus, the above-proposed method has a defect that, since the vapor-deposited metal film remaining in the binding wall strikingly lowers the cohesion strength of the binding wall, adhesive strength between the protective film and the binding wall, etc., retroreflective sheeting having excellent weather resistance cannot be obtained. Further, there is also a problem that, since the vapor-deposited metal film remaining on the support film surface between the glass beads in the sealed, small compartment cells gives dullness to the hue of the retroreflective sheeting, the vividness of color of the retroreflective sheeting is lowered. For improving the above defects, several attempts were also made for preventing the transfer of the vapor-deposited metal film, striking inhibiting the strength of the binding wall and giving a bad influence on the hue of the retroreflective sheeting. For example, a method of superposing a support film on the glass beads in the temporary support, and pressing the superposed matter, the method being characterized in that the pressing is conducted giving clearance so that the vapor-deposited metal film on the temporary support between the glass beads and the support film may not contact, is proposed in Japanese Laid-open Patent Publication No. 121043/1987 (=U.S. Pat. No. 4,897,136; EP-A-225,103). However, as to this proposed method, it is very difficult to conduct the pressing so that the glass beads may be sufficiently embedded in the support film, while enough clearance is maintained. Further, this proposed method has further defects that when the embedding of the glass beads in the support film is insufficient because of the change of the temperature condition and the pressure condition at the time of pressing, a large number of glass beads remain on the temporary support at the time of peeling the temporary support, and thereby strikingly poor appearance and poor retroreflective performance are caused, and on the other hand, in the case of excessive embedding, the support film and the vapor-deposited metal film are contacted partially or totally, and as a result, the vapor-deposited metal film is partially or totally transferred on the support film, and the weather resistance, hue, etc. of the resultant retroreflective sheeting are badly influenced thereby. Further, if, in a production step for encapsulated lens-type retroreflective sheeting, glass beads are embedded in the thermoplastic polymer layer of the temporary support while closely arranged so as to become a state of closest packing, the transfer of the vapor-deposited metal film can be avoided, but this is substantially impossible in an actual production step. The area on the temporary support covered with glass beads embedded is usually about 65 to 80% of the whole temporary support surface (becoming about 90% in the case of closest packing), and their distribution state is illustrated as a model in FIG. 2 and FIG. 3. FIG. 2 is a plan view showing the distribution model of glass beads (6) with which the temporary support (7) is covered, and as shown therein, glass beads are not uniformly distributed on the temporary support, and regions A where they do not exist and other regions where glass beads are comparatively closely arranged exist thereon. FIG. 3 is a model drawing showing the cross section of FIG. 2, glass beads (6) are embedded in the thermoplastic polymer layer (8) of the temporary support (7), and a vapor-deposited metal film (5) is formed on the about hemispherical surface of each of the glass beads and the temporary support. As is the case with FIG. 2, regions A where glass beads do not exist and other regions where glass beads are comparatively closely arranged exist on the temporary support. FIG. 4 is a model drawing showing the cross section of a laminate formed by superposing a support film (2) on glass beads (6) of the temporary support, and heating and pressing the resultant superposed matter. As apparent from FIG. 4, even if the pressing is conducted maintaining some clearance so that the support film (2) may not contact with the vapor-deposited metal film (5) on the temporary support, the support film (2), in the region A, easily contacts with the vapor-deposited metal film (5) on the temporary support, and there is a large possibility that when the temporary support is peeled, the vapor-deposited metal film at the part of the region A is transferred onto the support film. It is conducted, in actual industrial production of encapsulated lense-type retroreflective sheeting, to continuously produce a laminate from a long temporary support and a support film, once take it up in a roll state and temporarily store it, and then provide it for steps of or after the peeling of the temporary support. In this occasion, by influence of pressure, etc. of the take up roll (particularly, at the part nearer to the core of the roll), contact between the support film and the vapor-deposited metal film occurs even at parts where clearance between glass beads is comparatively narrow (for example, region B in FIG. 4), and as a result, a large amount of the vapor-deposited metal film is transferred onto the support film side, and becomes a cause of increase of inferior products occurrence ratio. Therefore, it is actually difficult to efficiently obtain a support film free of transfer of the vapor-deposited metal film by the method disclosed in Japanese Laid-open Patent Publication No. 121043/1987 (=U.S. Pat. No. 4,897,136; EP-A-225,103) comprising superposing and heat-pressing the support film and the temporary support, while maintaining clearance. In order to repair such defects, there is proposed in Japanese Laid-open Patent Publication No. 194405/1985 (=U.S. Pat. No. 4,653,854; GB-A-2,156,274) another method so as to perfectly avoid the contact between the support film and the vapor-deposited metal film, in which method there is further provided a thin layer of polymer having comparatively good adhesive strength to both the temporary support and the vapor-deposited metal film but having comparatively weak adhesive strength to the support film, on the surface of the temporary support on which glass beads are embedded and on which a vapor-deposited metal film is formed. It is possible without fail to perfectly avoid contact between the support film and the vapor-deposited metal film, by using this method. However, in general, a polymer capable of forming polymer thin layer has better adhesive strength to the support film containing the same or different kind of a polymer than to the vapor-deposited metal film on the temporary support, and therefore, it is actually extremely difficult to select a polymer having comparatively good adhesive strength to the temporary support and the vapor-deposited metal film but having comparatively weak adhesive strength to the support film, suggested in the above proposal. Any specific example of such polymers is not given at all in Japanese Laid-open Patent Publication No. 194405/1985 (=U.S. Pat. No. 4,653,854; GB-A-2,156,274). SUMMARY OF THE INVENTION The present inventors formed polymer thin layers using several polymers, and checked the transfer property of the vapor-deposited metal film, but there is a case where the polymer thin layer is transferred, with attachment of the vapor-deposited metal film, onto the support film side, and thus the above-proposed method is yet insufficient as a method for preventing the vapor-deposited metal film from being transferred onto the support film. The main object of this invention is to develop a method for surely preventing the vapor-deposited metal film on the temporary support between the glass beads from being transferred onto the support film, and thereby provide a method for producing superb retroreflective sheeting excellent in long-term weather resistance and having vivid color, particularly encapsulated lense-type retroreflective sheeting wherein vapor-deposited metal film pieces are not remaining in the binding wall and on the support film between the glass beads in the sealed, small compartment cells. The present inventors had made various, sequential researches into a method for producing retroreflective sheeting meeting the above objects, and as a result, they now found that excellent retroreflective sheeting free of the defects of the above prior art can be obtained by previously applying liquid matter containing a coupling agent on the vapor-deposited metal film on the temporary support where glass beads are embedded and a vapor-deposited metal film is formed, and drying the applied liquid matter to form a thin film containing the coupling agent, and completed the present invention. Thus, according to the invention is provided a method for producing retroreflective sheeting, which comprises embedding glass beads substantially in a monolayer in a temporary support at least one surface of which is composed of a thermoplastic resin in such a manner that at least part of each bead is embedded in the thermoplastic resin; forming a vapor-deposited metal film on the surface in which the glass beads were embedded; superposing thereon a thermoformable support film; pressing the resultant superposed matter under heating to embed the vapor-deposited metal film portion of each of the glass beads in the support film; and peeling the temporary support from the superposed matter in such a manner that the glass beads remain in the support film; and, if necessary, superposing a light-transmittable protective film on the exposed glass beads of the resultant support film in which the glass beads are embedded and partially thermally deforming the support film to form a large number of sealed, small compartment cells, between the support film and the light-transmittable protective film, surrounded by a continuous, linear wall which binds both these films, said method being characterized in that a thin film containing a coupling agent is previously formed on the vapor-deposited metal film on the temporary support in which the glass beads are embedded and on which the vapor-deposited metal film is then formed, and then the support film is superposed thereon. The method for producing retroreflective sheeting according to the invention is further detailedly described below. DESCRIPTION OF THE DRAWINGS The attached drawings are briefly described below. FIG. 1 is the cross section of encapsulated lens-type retroreflective sheeting. FIG. 2 is a plan view showing the distribution model of the glass beads with which the temporary support is covered. FIG. 3 is a model drawing showing the cross section of FIG. 2. FIG. 4 is a model drawing showing the cross section of the laminate formed by superposing the support film on the glass beads of the temporary support, and heating and pressing the resultant superposed matter. DESCRIPTION OF THE PREFERRED EMBODIMENTS The method of the invention has its large characteristic in the point that a coupling agent-containing thin film is previously formed on the temporary support where glass beads are embedded and a vapor-deposited metal film is formed on the whole top surface, in such a manner that the vapor-deposited metal film is covered therewith, and thereby, the vapor-deposited metal film is made not to be transferred onto the support film side, even if, thereafter, the support film and the vapor-deposited metal film on the temporary support contact. The coupling agent to be used in this invention can be a usual coupling agent generally used as a modifier of interface, for example, for chemically bonding together an inorganic material and an organic material, or different organic materials each other, and includes, for example, silane coupling agents, titanate coupling agents, aluminum coupling agents and zircoaluminum coupling agents. More specifically, those exemplified below can be used. (1) Silane coupling agents: Compounds represented by the general formula ##STR1## wherein X 1 represents a hydrolyzable group for example, an alkoxy group (e.g., a methoxy group, an ethoxy group, a 2-methoxyethoxy group, a 2-methoxy-2-ethoxyethoxy group, etc.), an acetoxy group, a chlorine atom, etc., a methoxy group is particularly preferred!, Y 1 represents an organic functional group reacting with an organic matrix for example, a vinyl group, a (meth)acryloyloxy group, an epoxy-containing group (e.g., a glycidoxy group, an epoxycyclohexyl group, etc.), a mercapto group, an amino group, an ureido group, a chlorine atom, an imidazolyl group, a cyano group, etc., preferably a (meth)acryloyloxy group or an epoxy-containing group!, Z 1 represents a nonhydrolyzable group for example, a methyl group, etc.!, R 1 represents a single bond or an alkylene group such as an ethylene group or an n-propylene group, preferably an n-propylene group, and n is 2 or 3, for example, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-methyl-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N- 2-(N-2-aminoethyl)aminoethyl!-3-aminopropyltrimethoxysilane, 3-ureidopropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, 3-(4,5-dihydroimidazolyl)propyltrimethoxysilane, 3-aminopropyltris(2-methoxy-2-ethoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-methacryloyloxypropylmethyldimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-aminopropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropyltriethoxysilane, 3-mercaptopropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-cyanopropyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, vinyltriacetoxysilane, vinyltrichlorosilane, 3-chloropropylmethyldichlorosilane, octadecyl 3-(trimethoxysilyl)propyl! ammonium chloride and N- 2-(N-vinylbenzyl)aminoethyl!-3-aminopropyltrimethoxysilane hydrochloride, etc. (2) Titanate coupling agents: 2-1) Compounds represented by the general formula X.sup.2.sub.p --Ti--Y.sup.2.sub.(4-p) (II) wherein X 2 represents a hydrolyzable group for example, an alkoxy group (e.g., a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, etc.), an acetoxy group, etc., or when p is 2, a group wherein two X 2 groups are combined (e.g., an oxyacetoxy group, an oxyethoxy group, etc.), preferably, an isopropoxy group, an oxyacetoxy group, an oxyethoxy group, etc., particularly preferably, an isopropoxy group!, Y 2 represents an organic group having affinity for or reactivity with an organic matrix for example, an acyloxy group (e.g., a (meth)acryloyloxy group, an octanoyloxy group, a lauroyloxy group, an oleoyloxy group, a stearoyloxy group, an isostearoyloxy group, etc.), an aryloxy group (a p-cumylphenoxy group, etc.), an arylsulfonyloxy group (a dodecylbenzenesulfonyloxy group, etc.), an alkylphosphonoxy group (e.g., a dioctylphosphonoxy group, a dioctylpyrophosphonoxy group, etc.), an amino group-containing group (e.g., a 2-N-(2-aminoethyl)aminoethoxy group), etc.!, and p is 0.5 to 2, for example, isopropyl trioctanoyl titanate, isopropyl triisostearoyl titanate, isopropyl diacryloyl isostearoyl titanate, isopropyl dimethacryloyl isostearoyl titanate, isopropyl tris(dodecylbenzenesulfonyl) titanate, isopropyl tris(p-cumylphenyl) titanate, isopropyl tris 2-N-(2-aminoethyl)aminoethyl! titanate, isopropyl tris(dioctylphosphono) titanate, isopropyl tris(dioctylpyrophosphono) titanate, bis(dioctylpyrophosphono) carbonylmethylene titanate, bis(p-cumylphenyl) carbonylmethylene titanate, diisostearoyl ethylene titanate, bis(dioctylpyrophosphono) ethylene titanate, etc. 2--2) Compounds represented by the general formula ##STR2## wherein X 3 represents a hydrolyzable group for example, an alkoxy group or substituted alkoxy group such as a methoxy group, an ethoxy group, an n-propoxy-group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, a 2-methoxyethoxy group, a 2-ethoxyethoxy group, a 2-butoxyethoxy group, a 3-methoxypropoxy group, a 2-methoxy-2-ethoxyethoxy group or a 2-methoxy-2-ethoxy-2-ethoxy-2-ethoxy group!, Y 3 represents an organic group having affinity for or reactivity with an organic matrix for example, an alkoxy group or substituted alkoxy group (e.g., an n-hexyloxy group, a 2-hexyloxy group, an n-octyloxy group, an isooctyloxy group, a tridecyloxy group, a stearyloxy group, a 2,2-diallyloxymethyl-1-butoxy group, etc.), an aryloxy group (e.g., a phenoxy group, a methoxyphenoxy group, etc.), a haloalkoxy group or haloaryloxy group (e.g., a bromomethoxy group, a chloroethoxy group, a chlorophenoxy group, etc.), etc.!, Z 2 represents, for example, an alkoxy group (e.g., a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, an n-hexyloxy group, an n-octyloxy group, an isooctyloxy group, a decyloxy group, a lauryloxy group, a tridecyloxy group, a stearyloxy group, etc.), a substituted alkoxy group (e.g., a 2-methoxyethoxy group, a 2-ethoxyethoxy group, a 2-butoxyethoxy group, a 3-methoxypropoxy group, a 2-methoxybutoxy group, a 2-methoxy-2-ethoxyethoxy group or a 2-methoxy-2-ethoxy-2-ethoxyethoxy group, etc.), an aryloxy group (e.g., a phenoxy group, a tolyloxy group, a xylyloxy group, cresyloxy group, a cumylphenoxy group, a methoxyphenoxy group, etc.), an aralkyloxy group (a benzyloxy group, etc.), a haloalkoxy group or haloaryloxy group (e.g., a bromomethoxy group, a chloroethoxy group, a 3-chloropropoxy group, a 2-chlorotridecyloxy group, a chlorophenoxy group, 2,4-dibromophenoxy group, etc.), etc., and m is 0 to 4, for example, tetramethyl bis(diphenyl phosphite)titanate, tetraethyl bis(dibenzyl phosphite)titanate, tetraisopropyl bis(dioctyl phosphite)titanate, tetraisopropyl bis(dilauryl phosphite)titanate, tetraisopropyl bis di(methoxyphenyl)phosphite!titanate, tetraisopropyl bis di(cumylphenyl) phosphite!titanate, tetraisobutyl bis(ditolyl phosphite)titanate, tetratert-butyl bis(dixylyl phosphite)titanate, tetrahexyl bis(dilauryl phosphite)titanate, tetraoctyl bis(dioctyl phosphite)titanate, tetraoctyl bis(dilauryl phosphite)titanate, tetraoctyl bis(ditridecyl phosphite)titanate, tetraoctyl bis(dicresyl phosphite)titanate, tetra(3-methoxypropyl) bis(dioctyl phosphite)titanate, tetra(2-methoxy-2-ethoxyethyl) bis di(2-chlorotridecyl) phosphiteltitanate, tetra(2-methoxy-2-ethoxy-2ethoxyethyl) bis(dicresylphosphite) titanate, tetra(2-butoxyethyl) bis(di-3-chloropropyl phosphite)titanate, tetra (2,2-diallyloxymethyl)butyl! bis(ditridecyl phosphite)titanate, methyl hexyl(2-ethoxyethyl)isooctyl bis (2,4-dibromophenyl) n-hexyl phosphite!titanate, tetraphenyl bis(dibutyl phosphite)titanate, dimethyl diphenyl bis(diisopropyl phosphite)titanate, tetra(methoxyphenyl) bis(dibutyl phosphite)titanate, tetra(chloroethyl) bis(octyl decyl phosphite)titanate, tetra(chlorophenyl) bis(dilauryl phosphite!titanate, tetra(bromomethyl) bis (di(methoxybutyl) phosphite!titanate, etc. (3) Aluminum coupling agents: Compounds represented by the general formula ##STR3## wherein X 4 represents a hydroxyl group or a hydrolyzable group for example, an alkoxy group such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, an isobutoxy group, a sec-butoxy group or a tert-butoxy group, etc.!, Y 4 represents an organic group having affinity for or reactivity with an organic matrix for example, an acyloxy group (e.g., a (meth)acryloyloxy group, an acetoacetoxy group, an octanoyloxy group, a lauroyloxy group, an oleoyloxy group, a stearoyloxy group, an isostearoyloxy group, a 1-amino-(N-lauroyloxy)propionyloxy group, etc.), an alkoxysulfonyloxy group (e.g., lauryloxysulfonyloxy group, etc.), an alkylsulfonyloxy group (e.g., a methylsulfonyloxy group, etc.), an arylsulfonyloxy group (e.g., a dodecylbenzenesulfonyloxy group, etc.), an alkylphosphonoxy group (e.g., a dibutylphosphonoxy group, a dioctylphosphonoxy group, a dioctylpyrophosphonoxy group, etc.), etc.!, Z 3 represents, for example, an alkyl group (a methyl group etc.), an aryl group (a phenyl group etc.), etc., Z 4 represents, for example, an alkyl group (a methyl group etc.), an alkoxy group or alkenyloxy group (e.g., an ethoxy group, a lauryloxy group, a stearyloxy group, an oleyloxy group, etc.), a substituted amino group (e.g., an N-stearylamino group, etc.), etc., and q is 0.5 to 2, for example, diisopropylate aluminum oleylacetoacetate, isopropylate acrylate aluminum oleylacetoacetate, isopropylate acetoactate aluminum oleylacetoacetate, isopropylate dibutyl phosphate aluminum oleylacetoacetate, isopropylate dibutyl pyrophosphate aluminum leylacetoacetate, isopropylate dodecylbenzene sulfonate luminum oleylacetoacetate, isopropyl ate lauryl sulfate luminum oleylacetoacetate, etc. (4) Zircoaluminate coupling agents: Compounds represented by the general formula ##STR4## wherein Y 5 represents an organic group having affinity for or reactivity with an organic matrix for example, an amino group, a carboxyl group, a (meth)acryloyloxy group, 1-methylvinyl group, a mercapto group, an acyloxy group, a dodecyl group, etc.!, and R 2 represents a single bond or an alkylene group of C 1 to C 18 for example, an ethylene group, an n-butylene group, an n-dodecylene group, etc.!, for example, 2-aminopropionyl zircoaluminate, 2-carboxypropionyl zircoaluminate, myristoyl zircoaluminate, methacryloyl zircoaluminate, 2-mercaptopropionyl zircoaluminate, etc. These coupling agents can be used alone or in combination of two or more. Silane coupling agents are particularly preferred. Formation of a coupling agent-containing thin film on the vapor-deposited metal film on the temporary support is not particularly limited, and can be conducted according to a method known per se, but, in general, a method of applying liquid matter containing a coupling agent can be used. As to the liquid matter containing a coupling agent, the coupling agent can be used as such, when the coupling agent itself is liquid matter having film formation ability, or can be used after being dissolved or dispersed in an appropriate solvent. It is preferred to use the coupling agent and a resin together because the resultant coupling agent-containing thin film usually becomes tougher. As usable resins therefor, there can be mentioned those having good weather resistance, for example, acrylic resins, polyester resins, polyurethane resins, fluorine-containing resins, etc., and these can be used alone or as a blend of two or more. The use amount of these resins can be varied according to the kind of coupling agent, the kind of resin, etc., but when it is desired to give toughness to coupling agent-containing thin film to be formed, it is generally suitable to use the resin at an amount in the range of 0.01 to 20 weight parts, preferably 0.05 to 15 weight parts, further preferably 0.1 to 12 weight parts, most preferably 10 weight parts or less based on 100 weight parts of the coupling agent. The viscosity characteristic of the coupling agent-containing liquid matter is not particularly limited so long as it is liquid capable of being applied, but it is, usually, suitable to adjust its viscosity using a diluent such as a-solvent appropriately, for making the control of the thickness of thin film to be formed easy, so that its viscosity at 23° C. may be in the range of 1 to 1,000 cP, preferably 1 to 500 cP. The coating method for the above coupling agent-containing liquid matter is also not particularly limited, and various methods known per se, for example, coating methods such as spray coating methods, gravure coating methods, bar coating methods, roll coating methods can be adopted. When a volatile substance such as a solvent is used for preparation of the liquid matter, a usual operation such as evaporating the volatile substance to dry the coating film can be added after the coating. Further, the film formed can be subjected to heating treatment at temperatures, for example up to about 100° C., depending on the used coupling agent. The thickness of the thus formed coupling agent-containing thin film is not particularly limited, and can widely be varied in accordance with the kind and amount of the coupling agent or resin used together, etc., but it is usually preferred in view of the assurance of thin film forming, easiness of operations, etc. to make the thickness, on average, in the range of about 0.01 to about 5 μm, more preferably about 0.05 to about 3 μm, particularly 0.1 to about 1 μm. The production of the retroreflective sheeting of the invention can be conducted using materials and methods so far known, for example, materials and methods disclosed in Japanese Patent Publication No. 7870/1965 (=U.S. Pat. No. 3,190,178; GB-B-1,017,060), Japanese Patent Publication No. 13561/1986 (=U.S. Pat. No. 4,025,159; GB-B-1,547,043), Japanese Laid-open Patent Publication No. 194405/1985 (=U.S. Pat. No. 4,653,854; GB-A-2,156,274), etc., except that after glass beads were partially embedded as a substantial monolayer in a temporary support at least one surface of which was composed of a thermoplastic resin, and a vapor-deposited metal film was formed on the surface where the glass beads are embedded, according to usual methods, respectively, a coupling agent-containing thin film is formed on the vapor-deposited metal film, as described above, according to the invention. An example thereof is described below. First, glass beads having a refractive index of the order of about 1.7 to about 2.0 and an average particle size of the order of 20 to 150 μm are embedded in a temporary support such as process paper having a thermoplastic resin such as a polyethylene resin as a surface layer in such a manner that about 1/3 to about 1/2 of the diameter of the glass beads is embedded in the thermoplastic resin surface layer, and a metal such as aluminum is vacuum-deposited on the exposed glass beads side of the temporary support to cover the about hemispherical surface of the glass beads with the vapor-deposited metal film. Then, liquid matter containing a coupling agent is applied onto the vapor-deposited metal film surface, and, if necessary, dried to form a coupling agent-containing thin film. Then, a support film formed on a process base material such as a polyethylene terephthalate process film, and the temporary support are superposed in such a manner that the support film and the glass beads on which the vapor-deposited metal film and the coupling agent-containing thin film were formed face each other, and the resultant superposed matter is pressed under heating until about 1/2 to about 1/3 of the diameter of the glass beads is embedded in the support film. It causes no hindrance if the support film is contacted with the coupling agent-containing thin film on the temporary support, but it is of course possible to conduct the pressing maintaining some clearance so as not to contact them. Then, the temporary support is peeled, a light-transmittable protective film such as an acrylic film is superposed on the exposed glass beads surface on the support film, and the support film is partially deformed under heating using, for example, an embossing roll having continuous, linear projections to bind the protective film and the support film through the resultant continuous, linear binding wall. As stated above, the invention provides a method for producing retroreflective sheeting, which comprises partially embedding glass beads, so as to be substantially a monolayer, in a temporary support at least one surface of which is composed of a thermoplastic resin, forming a vapor-deposited metal film on the surface where the glass beads were embedded, and then forming a coupling agent-containing thin film on the vapor-deposited metal film, whereby even if the support film and the vapor-deposited metal film on the temporary support are contacted, transfer of the vapor-deposited metal film onto the support film can be prevented, and thereby retroreflective sheeting excellent in adhesive strength between the protective film and the binding wall, and vividness of color, etc., and capable of maintaining excellent retroreflective performance for a long period can be produced without requiring complicated operation steps therefor. The invention is further specifically described below according to examples and comparative examples. EXAMPLE 1 A temporary support obtained by laminating polyethylene having a softening temperature of about 105° C. on paper was heated to about 105° C., glass beads having an average particle size of about 65 μm and a refractive index of about 1.91 were dispersed thereon uniformly and closely in a monolayer, and pressing was applied thereon using a nip roll to embed the glass beads in the polyethylene by about 1/3 of their diameter. Thereafter, aluminum was vacuum-deposited on the side of the temporary support where the glass beads were exposed to form a vapor-deposited metal film about 0.1 μm thick on almost the half spherical surface of the glass beads. Then, silane coupling agent liquid matter having a viscosity at 23° C. of about 2 cP (*) (produced by Toray Dow Corning Silicone Co., Ltd, trade name SZ6030) was applied on the vapor-deposited metal film on the temporary support where the vapor-deposited metal film was formed to form a coupling agent-containing thin film about 0.3 μm thick. (*) main component: 3-methacryloxypropyl-trimethoxysilane ##STR5## Then, the surface of a polyethylene terephthalate film of 20 μm thick on which peeling treatment had been made was coated with a composition comprising 100 weight parts of an acrylic resin solution having a solid content of about 50% by weight (produced by Tokushu Shikiryo Kogyo Co., Ltd., trade name ST-700) and 14.2 weight parts of a hexamethylene diisocyanate type crosslinking agent having a solid content of about 75% by weight, and the solvent was removed to give film-like matter about 30 μm thick. Thereon was applied a dispersion obtained by mixing under stirring 167 weight parts of an acrylic resin solution having a solid content of about 30% by weight (produced by Nippon Carbide Industries Co., Inc., trade name KP-1684A), 125 weight parts of an acrylic resin solution having a solid content of about 40% by weight (produced by Nippon Carbide Industries Co., Inc., trade name KP-1703A), 10 weight parts of cellulose acetate butyrate, 50 weight parts of rutile-type titanium dioxide and 30 weight parts of methyl isobutyl ketone, and the solvent was removed to give a support film having a total thickness of about 110 μm. This support film was superposed on the previously made glass beads on the temporary support on which beads the vapor-deposited metal film and the coupling agent-containing thin film were formed, and the superposed matter was pressed at a linear pressure of 900 kg/m under heating to 70° C. to embed about 1/3 of the glass beads in the support film. The resultant laminate sheet was wound up by about 500 m on a paper tube having an inner diameter of about 75 mm and an outer diameter of about 95 mm at a winding tension of 40 kg/m, and, then, the sheet was left alone at room temperature for 20 days so that the crosslinking reaction of the support film might be substantially completed, and, thereafter, the sheet was unwound. Then, the polyethylene laminate paper, i.e., the temporary support, was peeled off so that the glass beads might be transferred to the support film. The transfer ratio of the vapor-deposited metal film onto the resultant support film in which the glass beads were embedded was as shown in the later-described Table 1. Then, a non-oriented acrylic film having a thickness of 75 μm and a whole light transmittance of about 93% was superposed on the support film on which the glass beads were transferred in such a manner that the glass beads and the acrylic film faced each other, and while the resultant superposed matter was passed through between a metal roll having network projections having a line width of about 0.3 mm and a surface temperature of about 190° C. and a rubber roll having a surface temperature of about 60° C. in such a manner that the acrylic film side was contacted with the rubber roll, the metal roll was pressed on the peeling-treated polyethylene terephthalate film side to conduct partial thermal fusion deforming. The peeling-treated polyethylene terephthalate film was removed from the resultant thermal fusion deforming matter, and an acrylic pressure sensitive adhesive (produced by Nippon Carbide Industries Co., Inc., trade name KP-997) about 40 μm thick formed on a silicone-treated polyethylene terephthalate peeling film about 75 μm thick was laminated on and stuck to the resultant thermal fusion deforming matter in such a manner that the support film and the pressure sensitive adhesive were contacted, whereby retroreflective sheeting was produced. The performance of the resultant encapsulated lens-type retroreflective sheeting is as shown in the later-described Table 1, and the retroreflective sheeting produced by the production method of the invention was excellent in vividness of color, and, even in the severe weathering test, exhibited only a low lowering ratio of retroreflective performance, was almost free of the peeling of the protective film, and thus had excellent characteristics. EXAMPLE 2 Retroreflective sheeting was produced in all the same manner as in Example 1 except that liquid matter having a viscosity at 23° C. of about 1.5 cP produced by mixing 17 weight parts of the same silane coupling agent as used in Example 1 (trade name SZ6030) with 1 weight part of an acrylic resin solution having a solid content of about 1% by weight (an ethyl acetate solution of an acrylic copolymer having a weight average molecular weight of about 300,000 obtained by copolymerizing 54% by weight of ethyl acrylate with 46% by weight of methyl methacrylate), was applied, and a coupling agent-containing thin film was formed by drying of 3 minutes at 90° C. The transfer ratio of the vapor-deposited metal film onto the resultant support film and the performance of the obtained encapsulated lens-type retroreflective sheeting were as shown in the later-described Table 1, and the retroreflective sheeting produced by the production method of the invention was excellent in vividness of color, and, even in the severe weathering test, exhibited only a low lowering ratio of retroreflective performance, was almost free of the peeling of the protective film, and thus had excellent characteristics. EXAMPLE 3 Retroreflective sheeting was produced in all the same manner as in Example 2 except that aluminum coupling agent liquid matter (*) (produced by AJINOMOTO CO., INC., trade name Plenact AL-M) was used in place of the silane coupling agent. (*) Main component: acetoalkoxy aluminum diisopropylate ##STR6## The performance of the resultant encapsulated lens-type retroreflective sheeting is as shown in the later-described Table 1, and the retroreflective sheeting produced by the production method of the invention was excellent in vividness of color, and, even in the severe weathering test, exhibited only a low lowering ratio of retroreflective performance, was almost free of the peeling of the protective film, and thus had excellent characteristics. EXAMPLE 4 Retroreflective sheeting was produced in all the same manner as in Example 2 except that titanate coupling agent liquid matter having a viscosity at 23° C. of about 20 cP (*) (produced by AJINOMOTO CO., INC., trade name Plenact KR46B) was used in place of the silane coupling agent. (*) Main component: tetraoctyl bis(ditridecyl phosphite)titanate (C 8 H 17 --O) 4 Ti P(OC 13 H 27 ) 2 OH! 2 The transfer ratio of the vapor-deposited metal film onto the resultant support film and the performance of the obtained encapsulated lens-type retroreflective sheeting were as shown in the later-described Table 1, and the retroreflective sheeting produced by the production method of the invention was excellent in vividness of color, and, even in the severe weathering test, exhibited only a low lowering ratio of retroreflective performance, was almost free of the peeling of the protective film, and thus had excellent characteristics. EXAMPLE 5 Retroreflective sheeting was produced in all the same manner as in Example 1 except that a coupling agent-containing thin film was formed in the same manner as in Example 2; the acrylic resin components for the support film of Example 1 were changed to 100 weight parts of an acrylic resin solution having a solid content of about 50% by weight (produced by Tokushu Shikiryo Kogyo Co., Ltd., trade name ST-700) and 14.2 weight parts of a hexamethylene diisocyanate type crosslinking agent having a solid content of about 75% by weight, and 100 weight parts of an acrylic resin solution having a solid content of about 50% by weight (produced by Nippon Carbide Industries Co., Inc., trade name KP-1821A), 10 weight parts of cellulose acetate butyrate, 15 weight parts of rutile-type titanium dioxide and 10 weight parts of a hexamethylene diisocyanate type crosslinking agent having a solid content of about 75% by weight; and the superposed matter was pressed at a linear pressure of 900 kg/m under heating to 85° C. so that about 1/2 of the glass beads might be embedded in the support film. Then, the obtained laminate sheet was left alone at ordinary temperature for 4 days so that the crosslinking reaction of the support film might progress by about 40% to give embossing suitability, and, thereafter, the sheet was unwound. Then, the polyethylene laminate paper, i.e., the temporary support, was peeled off so that the glass beads might be transferred onto the support film. The transfer ratio of the vapor-deposited metal film onto the resultant support film and the performance of the obtained encapsulated lens-type retroreflective sheeting were as shown in the later-described Table 1, and the retroreflective sheeting produced by the production method of the invention was excellent in vividness of color, and, even in the severe weathering test, exhibited only a low lowering ratio of retroreflective performance, was almost free of the peeling of the protective film, and thus had excellent characteristics. Comparative Example 1 Retroreflective sheeting was produced in all the same manner as in Example 1 except that the coupling agent-containing thin film was not formed. The transfer ratio of the vapor-deposited metal film onto the resultant support film and the performance of the obtained encapsulated lens-type retroreflective sheeting were as shown in the later-described Table 1, and the retroreflective sheeting was inferior in vividness of color, and, in the weathering test, exhibited a large lowering ratio of retroreflective performance and the peeling of the protective film, and thus had inferior characteristics. Comparative Example 2 Retroreflective sheeting was produced in all the same manner as in Example 2 except that the acrylic resin solution mixed with the coupling agent in Example 2 was used alone to form a polymer thin film in place of the coupling agent-containing thin film. The transfer ratio of the vapor-deposited metal film onto the resultant support film and the performance of the obtained encapsulated lens-type retroreflective sheeting were as shown in the later-described Table 1, and the retroreflective sheeting was inferior in vividness of color, and, in the weathering test, exhibited a large lowering ratio of retroreflective performance and the peeling of the protective film, and thus had inferior characteristics. Further, as to retroreflective performance, the retroreflective sheeting was inferior at the angle conditions of an incident angle of 40° and an observation angle of 0.2°. Measuring methods on the tests used in Table 1 were as follows. (1) Average thickness of thin film The average thickness of a coupling agent-containing thin film or a polymer thin film was calculated according to the following calculation equation. ##EQU1## A: Weight (g) of liquid matter applied B: Area (m 2 ) of place where liquid matter was applied C: % by weight of volatilization residue in liquid matter D: Specific gravity of volatilization residue (2) Evaluation of transfer area ratio of aluminum vapor-deposited metal film onto support film The laminate of the support film and the polyethylene laminate paper as a temporary support left alone at room temperature for a certain period was unwound while peeling the temporary support, and cut out at the spot of about 5 m from the terminal of the unwound roll of the resultant support sheeting to which the glass beads were transferred, and the support film area where glass beads were not embedded and the aluminum vapor-deposited metal film transfer area were determined under a microscope of a magnification of 200-fold using a picture processing apparatus (produced by OLYMPUS OPTICAL CO., LTD., Model VM-30), the transfer area ratio of the aluminum vapor-deposited metal film onto the support film was calculated according to the following equation, and the transfer area ratio was evaluated according to the following criterion. ##EQU2## 1: Transfer area ratio of vapor-deposited metal film onto the support film under 1% 2: Transfer area ratio of vapor-deposited metal film onto the support film 1--under 30% 3: Transfer area ratio of vapor-deposited metal film onto the support film 30--under 60% 4: Transfer area ratio of vapor-deposited metal film onto the support film 60--under 90% 5: Transfer area ratio of vapor-deposited metal film onto the support film 90% or more (3) Retroreflective performance The resultant retroreflective sheeting was unwound, and the retroreflective performance of the resultant retroreflective sheeting at the spot of about 5 m from the terminal of the unwound roll was measured according to the reflective performance measurement method described in JIS Z-9117. Angle conditions used were the conditions of an observation angle of 0.2° and an incident angle of 5°, and the conditions of an observation angle of 0.2° and an incident angle of 40° (4) Vividness of color The resultant retroreflective sheeting was unwound, and the hue of the retroreflective sheeting at the spot of about 5 m from the terminal of the unwound roll was measured according to the measurement of color described in JIS Z-9117, and the hue was determined by the L*, a* and b* color specification system, and the vividness of color was calculated according to the following calculation equation. ##EQU3## (5) Lowering ratio of retroreflective performance after Weathering test The resultant retroreflective sheeting was unwound, and the retroreflective sheeting at the spot of about 5 m from the terminal of the unwound roll was cut into 50 mm×50 mm, the silicone-treated polyethylene terephthalate peeling film was peeled off, and the resultant retroreflective sheeting was stuck on an aluminum panel. The resultant stuck sample was placed in an accelerated weatherometer (produced by Atlas Chemical Industries, Inc., Xenon Weatherometer Type-Ci35A, black panel temperature 80±3° C., spray cycle 18 minutes in 120 minutes), and subjected to a 1,000 hours accelerated weathering test. Thereafter, the stuck sample was taken out, and subjected to a heat shock cycle test using a heat shock cycle tester (produced by TABAI ESPEC CORP., Heat Shock Chamber TSR-63). As to heat shock cycles, the following condition was made to be 1 cycle, and a 200 cycles test was conducted. Heat shock cycle condition: -40° C.×30 min→room temperature ×15 min→145° C.×30 min room temperature ×15 min Retroreflective performance (angle conditions: observation angle 0.2°, incident angle 5°) was measured on the stuck sample after the heat shock cycle test, and compared with the retroreflective performance of the specimen before the tests, and the lowering ratio after the weathering tests was calculated according to the following calculation equation. Retroreflective performance lowering ratio (%) after weathering tests ##EQU4## (6) Peeling of protective film after weathering tests After the weathering test by the same accelerated weathering test and the heat shock cycle test as described above were conducted, the part where the binding wall binding the protective film to the support film was destroyed, was measured, at the site where destruction of maximum length from the edge was made, and the measured length was defined as protective film peeling. TABLE 1__________________________________________________________________________ LoweringAverage Evaluation of ratio ofthickness transfer area Retroreflective retroreflective Peeling ofof thin ratio of aluminum performance Vividness performance protective filmfilm vapor-deposited (cd/1 × .m.sup.2) of after weathering after weathering(μm) metal film 0.2°/5° 0.2°/40° color test (%) test (mm)__________________________________________________________________________Example 1 0.3 1 356 241 63.5 0 0Example 2 0.3 1 333 220 63.2 0 0Example 3 0.3 1 348 230 63.3 0 0Example 4 0.3 1 330 218 63.0 0 0Example 5 0.3 1 332 242 63.0 0 0Comparative -- 4 346 161 59.8 18 2example 1Comparative 0.3 5 342 186 60.7 6 1example 2__________________________________________________________________________

4y

BACKGROUND OF THE INVENTION The present invention relates generally to electrical sockets, and, more particularly, to electrical sockets that receive reinforced corners. In some types of electronic packaging, electrical sockets are provided that are surface mounted to a printed circuit board. For example, land grid array (“LGA”) and ball grid array (“BGA”) packaging include socket structures surface mounted to printed circuit boards including a matrix of corresponding surface mounted flat pad structures upon each of which is deposited a small quantity of solder. To mount the socket structure to the circuit board, the socket is typically placed on an appropriate side of the circuit board, using a high accuracy “pick and place” machine, in a manner such that the solder lead portions of the socket contact a number of flat, surface mounted solder pads on the board. Once the socket is located on the board, the board is heated, causing the solder to melt, thereby fusing the corresponding surfaces together and yielding a strong mechanical and electrical connection when cooled. Even slight nonplanarities in either or both of the circuit board and surface mounted electronic packages tend to compromise the electrical connections of the electronic package to the board. Consequently, nonplanarities of the board or the electronic package tend to significantly increase the probability of having to rework a significant portion of the fabricated circuit board/electronic package assemblies, thereby undesirably increasing assembly and reducing yield. As the data transmission rates of modern electronic devices increase, the size of the electronic package to accommodate an increased number of signals is also increasing. For example, in at least one application, sockets are required that approach 74 mm in length. An increased size of the packages, however, tends to result in warping of the plastic sockets used in the packages as they are surface mounted to the board. Specifically, heat from the solder reflow process creates residual stress in the plastic socket as the socket cools, thereby causing the socket to warp and become nonplanar with respect to the circuit board. Distortion and deformation of the socket is an undesirable and unwelcome aspect of the surface mount electronic package assembly. BRIEF DESCRIPTION OF THE INVENTION A cover for an electrical socket is provided in accordance with one aspect of the present invention. The cover comprises multiple walls joined with one another and configured to overlay an electrical socket. A latch element is provided on at least one of the walls to securely retain the walls against the electrical socket. A rigid member is secured to the walls and retains the walls in a predefined relation with respect to one another. Optionally, the said walls of the cover surround an opening that extends through the socket, and the rigid member spans the opening. In a further option, the rigid member includes a heat resistant plate rigidly mounted to the walls. In another option, the walls of the cover include lower edges aligned in a common plane, and the lower edges are configured to abut against and retain the electrical socket in a common plane. In a further option, the walls include upper edges that abut against the rigid member which maintain the walls in a common planar relation with one another. In still another option, the walls include brackets that slidably receive the rigid member. In accordance with another aspect of the present invention, the cover is provided with a latch beam that is pivotally mounted to one of the walls. The latch beam has a length oriented to extend along a length of one of the walls. The latch beam is configured to securely retain the electrical socket to the cover. In accordance with still another aspect of the present invention, an electronic package is provided. The package comprises an electrical socket and a cover with multiple walls joined with one another and configured to overlay the electrical socket. A latch element is provided on at least one of the walls to securely retain the walls against the electrical socket. A rigid member is secured to the walls and retaining the walls in a predefined relation with respect to one another. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is perspective view of an exemplary electronic package assembly formed in accordance with an embodiment of the present invention. FIG. 2 is a top plan view of a cover for the socket assembly shown in FIG. 1 formed in accordance with an embodiment of the present invention. FIG. 3 is an end elevational view of the cover shown in FIG. 2 formed in accordance with an embodiment of the present invention. FIG. 4 is an exploded perspective view of a reinforced cover assembly for the package shown in FIG. 1 formed in accordance with an embodiment of the present invention FIG. 5 is a top plan view of the package shown in FIG. 1 with the cover assembly in a latched position. FIG. 6 is a magnified view of a portion of the package shown in FIG. 5 . FIG. 7 is a top plan view of the package shown in FIG. 1 in an unlatched position. FIG. 8 is a perspective view of another embodiment of an electronic package. FIG. 9 is a partial cross sectional view of a portion of the socket and frame shown in FIG. 8 . DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a perspective view of an exemplary electronic package 100 including a socket 102 and a cover assembly 104 attached to the socket 102 . As explained in detail below, cover assembly 104 overlays socket 102 and prevents socket 102 from warping such as during solder reflow processes in surface mount installations and such as in ball grid array (“BGA”) packaging. Package 100 is particularly suited for larger socket openings, such as for, example, a distributed power delivery system for an electronic device, although it is understood that the benefits of the invention and/or disclosed embodiments may be used in other applications. For example, while package 100 has been found to be advantageous for BGA packaging, it is recognized that package 100 may also be used in land grid array (“LGA”) packaging. The embodiments described hereinbelow are therefore set forth for purposes of illustration rather than limitation, and the invention is not intended to be limited to any particular socket configuration or to sockets for any particular end application. Socket 102 , as further described below, is generally rectangular in shape in an exemplary embodiment and includes four sides 106 extending substantially perpendicular to one another and joined at respective ends thereof. Each side 106 of socket 102 includes a pair of projections or tabs 108 , sometimes referred to as fences, extending upwardly therefrom for secure engagement with cover assembly 104 . Socket 102 further includes a number of openings therein for receiving power and/or signal contacts of a mating electronic card interposer (not shown). In an illustrative embodiment, socket 102 is fabricated from known materials, including but not limited to injection molded plastic, and is configured for surface mounting to a printed circuit board (not shown). In other words, a bottom surface of socket 102 is substantially flat and coplanar to form a secure mechanical and electrical connection when surface mounted to the printed circuit board. While a generally rectangular socket configuration is illustrated, it is appreciated that other socket shapes having a greater or fewer number of sides may be employed. It is further recognized that a greater or fewer number of projections or tabs 108 may be employed. As illustrated in FIG. 1 , cover assembly 104 is generally complementary in shape to socket 102 and is configured to be hingedly attached to socket 102 through projections 108 . Upstanding side walls extend about the remaining sides of cover assembly 104 and include pivotally mounted latch members thereon (explained further below) for securing cover assembly 104 to socket 102 . Cover assembly 104 is adapted for use with a known pick and place machine for placement of socket 102 on the printed circuit board, and further is adapted to prevent warping and deformation of socket 102 during heating, such as during a solder reflow process. More particularly, cover assembly 104 includes a reinforcing rigid member 110 therein that is heat resistant and maintains socket 102 in a planar arrangement. Optionally, rigid member 110 is fabricated from a known metal, such as stainless steel into a flat, planar plate according to known processes or techniques. Alternative rigid member 110 may be fabricated from a known ceramic material according to a known process to produce a heat resistant reinforcement member that does not deform during heating and thereby maintains socket 102 in a planar arrangement. FIG. 2 is a top plan view of pick and place cover 120 which receives rigid member 110 therein to form cover assembly 104 (shown in FIG. 1 ). As illustrated in FIG. 2 , cover 120 is generally rectangular and includes four substantially orthogonal side walls 122 , 124 , 126 , 128 with a planar top surface 130 extending therebetween and including angled corners between the side walls. While the top surface 130 of the cover 120 extends entirely between side walls 122 , 124 , 126 , 128 , it is understood that top surface 130 may include one or more openings therethrough in alternative embodiments without departing from the scope and spirit of the instant invention. In an exemplary embodiment, one side wall 122 includes hinge elements 132 , 134 extending therefrom, while the remaining three sides walls 124 , 126 , 128 include latch elements 136 depending outwardly therefrom. Side walls 124 , 126 , 128 further include brackets 138 extending upward above the top cover surface 130 and extending inward toward one another over a portion of the top surface 130 . Each hinge element 132 , 134 includes a respective slot 140 , 142 for receiving projections 108 along one side of socket 102 (as shown in FIG. 1 ). Brackets 138 form a pocket for receiving the rigid reinforcement member 110 (shown in FIG. 1 ). Latch elements 136 on the cover 120 are arranged in pairs along side walls 124 , 126 , 128 and are disposed symmetrically on either side of lateral and longitudinal axes 144 , 146 extending through a center 148 of cover 120 . Each latch element 136 includes a latch beam 150 extending substantially parallel to respective side walls 124 , 126 , 128 . Each latch beam 150 is joined to the side walls 124 , 126 , 128 by a web 152 projecting substantially perpendicularly to the side walls 124 , 126 , 128 . Latch beams 150 include grip portions 154 on lateral ends thereof. The grip portions 154 are located adjacent the cut-out corners of cover surface 130 . The latch beams 150 also include rounded pivot ends 156 that are located adjacent cover axes 144 , 146 . In an exemplary embodiment, and as illustrated in FIG. 2 , grip portions 154 extend inwardly from latch beams 150 . As explained below, grip portions 154 resiliently receive projections 108 of socket 102 (shown in FIG. 1 ) and maintain the projections 108 between grip portions 154 and side walls 124 , 126 , 128 . FIG. 3 is an end elevational view of cover 120 to better illustrate brackets 138 extending upwardly from and extending over cover top surface 130 . Each bracket 138 includes a slot 170 that receives an edge of rigid member 110 (shown in FIG. 1 ) in an interference fit to securely retain the rigid member 110 in a planar position with respect to cover 120 . Thus, when cover assembly 104 (shown in FIG. 1 ) is engaged by vacuum pickups of a pick and place machine, cover 120 and rigid member 110 are maintained in their respective planar orientations, thereby imparting structural strength and stiffness to socket 102 (shown in FIG. 1 ) to resist heat-related stresses and deformation during solder reflow operations when surface mounting the electronic package. As also illustrated in FIG. 3 , latch members 136 , and more specifically, latch beams 150 are elevated above cover surface 130 at pivot ends 156 . As such, pivot ends 156 are located above rigid member 110 when the rigid member 110 is received in brackets 138 . This clearance of the rigid member 110 allows pivot ends 156 to be actuated as explained below to release cover assembly 104 from the socket 102 after being soldered to the printed circuit board. In an exemplary embodiment, cover 120 is integrally fabricated according to a known process, including but not limited to a molded piece fabricated from a high temperature nylon material A unitary construction suitable for transferring structural rigidity of rigid member 110 to socket 102 to maintain socket 102 in a planar relationship to the printed circuit board is thereby provided. It is contemplated, however, that other known materials (e.g. injection molded plastic and thermoplastic materials, metallic materials and alloys, and ceramic materials) and processes appropriate for those materials may be used in lieu of plastic molding to produce cover 120 in both integral construction and constructions of multiple pieces. FIG. 4 is an exploded perspective view of rigid member 110 and cover 120 . The rigid member 110 is fabricated into a planar element complementary in shape to the top surface 130 of the cover 120 , and is dimensioned to a sufficient thickness to resist warping stresses in socket 102 and prevent deformation of socket 102 during heating. The rigid member 110 slides over top surface 130 and is snugly engaged in brackets 138 to complete cover assembly 104 (shown in FIG. 1 ). Due to the structural strength and rigidity of rigid member 110 , the cover 120 need not be as structurally rigid as it would otherwise. Accordingly, cover 120 may be fabricated from less costly materials in a less costly manner while still ensuring that socket 102 is maintained in a coplanar relationship with the printed circuit board. FIG. 5 is a top plan view of package 100 (shown in FIG. 1 ) illustrating cover assembly 104 attached to socket 102 in a latched position. The latch elements 136 are fitted over respective socket projections 108 along one side of the assembly 100 . Along the remaining sides, socket projections 108 are received between outer surfaces of side walls 124 , 126 , 128 and grip portions 154 of latch elements 136 . Rigid member 110 is received in brackets 138 and provides a sturdy reference plane to maintain socket 102 in a planar orientation and to counteract the tendency of the socket 102 to deform during solder reflow operations. When cover assembly 104 is attached to socket 102 in the latch position, package 100 may be positioned on a printed circuit board with a pick and place machine, and socket 102 may be surface mounted to the printed circuit board with a solder reflow operation. FIG. 6 is a magnified view of a portion of package 100 . The grip portion 154 includes a tapered shelf 180 extending beneath a lower surface 182 of one of socket projections 108 . Thus, latch element 136 forms a wrap-around engagement with socket projection 108 . Hence, when cover assembly 104 is lifted for positioning on a printed circuit board, tapered shelves 180 of latch elements 136 afford support from beneath socket projections 108 . Gravitational forces tending to separate the cover assembly 104 and socket 102 , when package 100 is lifted, are therefore counteracted. Accordingly, the socket 102 is maintained in a desired position relative to cover assembly 104 . A bottom surface of the grip portion 154 in FIG. 6 is located to extend a predetermined distance above the printed circuit board once the socket 100 is installed. For example, in one embodiment, a vertical clearance of greater than 2.0 mm is provided so that desired electrical components may be located underneath the grip portions 154 when the package 100 is installed on a circuit board. It is contemplated that greater or lesser clearances and other dimensional variations may be used for alternative installations of package 100 . FIG. 7 is a top plan view of electronic package 100 illustrating cover assembly 104 in an unlatched position for removal from socket 102 once solder reflow operations are complete. Latch elements 136 are actuated to the unlatched position by depressing pivot ends 156 inward toward respective side walls 124 , 126 , 128 . As pivot ends 156 are depressed, latch beams 150 are pivoted about webs 152 where the latch elements 136 are attached to the side walls 124 , 126 , 128 . In turn, grip portions 154 are deflected outwardly and away from respective side walls 124 , 136 , 128 until projections 108 are released from the grip portions 154 . Once projections 108 are released, the cover 104 may be rotated upward about hinge elements 132 , 134 (as shown in FIG. 1 ) until hinge elements 132 , 134 are released from tab projections 108 and the cover assembly 104 may be removed. When the cover assembly 104 is removed, the socket 102 remains in secure mechanical and electrical connection to the printed circuit board in a planar relationship thereto. Likewise, cover assembly 104 may be latched to socket 102 by inserting hinge elements 132 , 134 socket projections 108 on one end of the socket 102 , and rotating the cover assembly 104 downward about hinge elements 132 , 134 toward socket 102 . By depressing pivot ends 156 , grip portions 154 are deflected outwardly as latch beams 150 pivot about webs 152 . Hence, socket projections 108 may be aligned between side walls 124 , 126 , 128 and grip portions 154 as shown in FIG. 7 . When the pivot ends 156 are released (i.e., not depressed) latch elements 136 resiliently return to the latched position (shown in FIG. 5 ) wherein cover assembly 104 is securely engaged to the socket 102 . In an illustrative embodiment, flexibility of the latch elements 136 to pivot about webs 152 is provided by the molded properties of the cover 120 . In particular, the webs 152 are resilient in one direction (as denoted by arrow A in FIG. 7 ) to allow resilient flexing of latch elements 136 to latch or unlatch the cover assembly 104 to the socket 102 . The arrow A represents an actuator path about an axis of rotation extending perpendicular to the plane containing the rigid member 110 . In addition, the webs 152 are appreciably stiff in other directions to impart structural strength to the socket 102 to resist deformation of the side walls 124 , 126 , 128 along the axis of rotation. Specifically, webs 152 are stiff in a direction perpendicular to the surface of cover 120 , together with side walls 124 , 126 , 128 . As such, the rigid member 110 of the cover assembly 104 provides horizontal and vertical stiffness to the socket 102 , while the cover 120 provides vertical stiffness to the socket 102 to maintain socket 102 in a planar position and orientation with respect to the printed circuit board. According to another aspect of the present invention, and in an illustrative embodiment, the cover assembly 104 is configured to be maintained within a predetermined envelope 200 (shown in phantom in FIG. 7 ) regardless of whether the cover 120 is in the latched position (shown in FIG. 5 ) or the unlatched position (shown in FIG. 7 ). Interference of the latch elements 136 with other circuit board components is therefore avoided, and space on the printed circuit board is preserved. In an exemplary embodiment, envelope 200 is a square. It is appreciated that other design envelopes of various shapes and sizes may be provided in alternative embodiments and other applications of package 100 . FIG. 8 is a perspective view of another embodiment of a cover assembly for an electronic package 250 including a stiffening cover or frame 254 situated about a socket 256 and maintaining socket 256 in a coplanar position relative to a printed circuit board. The frame 254 includes multiple walls 258 extending generally complementary to the outer profile of the socket 256 , and the socket 256 is received in the frame 254 . Once the socket 256 is received in the frame 254 , the socket and frame assembly is then located on the printed circuit board (not shown in FIG. 8 ) for solder reflow operations as described above. As illustrated in FIG. 8 , the socket 256 includes oppositely positioned C-shaped elements contained in either end of the socket frame 254 and connected to one another. The C-shaped elements of socket 256 defines a cross-shaped opening 262 therebetween. It is contemplated, however, that in alternative embodiments the socket 256 may assume a variety of shapes defining various openings therebetween to accommodate various socket applications. In an exemplary embodiment the socket 256 is fabricated from, for example, injection molded plastic according to known techniques, while the frame 254 is fabricated from metal. As such, the frame 254 is fabricated from a much stiffer or rigid material than the material from which the socket 156 is fabricated. The stiffness of the frame 254 resists heat related stress and deformation and maintains the socket 256 in a planar orientation relative to the printed circuit board. Further, in various embodiments, the frame 254 and the socket 256 may be fabricated from any of the foregoing materials and processes to produce suitable stiffness to resist deformation during solder reflow processes. FIG. 9 is a partial cross sectional view of a portion of the electronic package 250 illustrating an exemplary tongue-in-groove latch connection of the socket 256 within the frame 254 . A side wall 258 of the frame 254 abuts against the socket 256 and retains the socket 256 in a planar position. Specifically, a tongue 280 extends laterally outward from the socket 256 and is received in a groove 282 extending on the interior portion of the frame 254 . While in the illustrated embodiment the tongue 280 extends from an edge of the socket 256 and is received in the groove 282 extending in the interior surface of the frame 254 , it is appreciated that in an alternative embodiment a tongue extending from the frame 254 could be accommodated by a groove in an edge of the socket 256 . The tongue and groove arrangement may extend wholly or partially around the mating surfaces of the socket 256 and the frame 254 to provide a suitable latching engagement of the socket 256 and frame 254 . It is contemplated that in further and/or alternative embodiments, other connection and latch arrangements familiar to those in the art may be used to attach the socket 256 to the frame 254 . Additionally, the socket 256 and/or the frame 254 may exhibit flexiblity to install and remove the socket 256 to the frame 254 while achieving a sufficient rigidity to withstand solder reflow operations without deformation. As such, associated nonplanarities of the socket and the printed circuit board are avoided. While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.

4y

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 60/315,630, filed Aug. 29, 2001. FIELD OF THE INVENTION [0002] The present invention relates generally to heat shrink tools and more particularly to a device for accurate assembly of a tool to a tool holder by the heat shrink method. BACKGROUND OF THE INVENTION [0003] Connecting a tool to a tool holder by the heat shrink method is a well-known process. An example of the general process is described in U.S. Pat. No. 5,311,654 issued to Harold D. Cook on May 17, 1994. The heat shrink process is typically used with a tool holder having a bore for receipt of a tool having a shank. The tool holder is heated to expand the tool holder bore. The shank of the tool is then inserted into the bore. As the tool holder cools, the bore shrinks around the shank holding the shank within the tool holder. [0004] The heat shrink method is an effective method for connecting a tool to a tool holder. However, in most applications, the tool must be precisely mounted within the tool holder or the tool holder cannot be used. It should be appreciated that these tools are typically used in operations that require very precise alignment and positioning. Slight variations in the alignment between tool and tool holder results in the production of defective parts. One of the major disadvantages of known methods for connecting a tool to a tool holder using the heat shrink method is the need to measure each tool and tool holder and the inaccuracy that can result from these repetitive measuring operations. Human error is a significant factor. A worker must measure the tool length and the tool holder length and then adjust the position of the tool to get the appropriate overall length. To reduce human error somewhat, another method employs a pre-qualified measuring rod to determine the appropriate depth of the tool within the tool holder. When this rod wears, the positioning is wrong and resultant tools and tool holders cannot be used. Furthermore, the heat shrink process must be done quickly to avoid down time when changing tools. If the heat shrink method is slow, tool changes will be slow resulting in the overall slowing of the entire operation in which the tool and tool holder are being used. [0005] Accordingly, it would be advantageous to provide a tool assembly unit for rapidly and precisely connecting a tool to a tool holder. SUMMARY OF THE INVENTION AND ADVANTAGES [0006] It is an object of the present invention to provide a tool assembly unit for coupling a tool and a tool holder. The unit includes a measuring device adapted to determine the position of the tool with respect to the tool holder, an alignment device coupled to the measuring device and being adapted to receive the tool holder, a moveable rod slideably disposed on the alignment device and coupled to the tool, with the rod being adapted to move the tool with respect to the tool holder to a desired position as measured by the measuring device. [0007] It is another object of the present invention to provide a tool assembly unit for coupling a tool and a tool holder by heat shrinking. The unit includes a measuring device adapted to determine the position of the tool with respect to the tool holder, an alignment device coupled to the measuring device and being adapted to receive the tool holder, a heating device slideably mounted on the alignment device and defining a bore for sliding a tool therethrough with the heating device adapted to be removably mounted on the tool holder for heating the tool holder, a moveable rod slideably disposed on the alignment device and being adapted to be coupled to the tool, with the rod being further adapted to move the tool with respect to the tool holder to a desired position as measured by the measuring device. [0008] It is still another object of the present invention to provide a method for coupling a tool with a tool holder using a tool assembly unit including a measuring device coupled to an alignment device and a moveable rod slideably disposed on the alignment device. The method includes the steps of mounting the tool holder on the alignment device, coupling the moveable rod to the tool, measuring an actual relative position between the tool and tool holder, moving the tool within the tool holder until the actual relative position of the tool relative to the tool holder is equal to a desired position, and removing the tool holder and the tool from the alignment device. [0009] It is still another object of the present invention to provide a method for coupling a tool with a tool holder by heat shrinking using a tool assembly unit including a measuring device coupled to an alignment device having a heating device slideably mounted thereon and a moveable rod slideably disposed on the alignment device. The method includes the steps of mounting the tool holder on the alignment device, heating the tool holder, coupling the moveable rod to the tool, measuring an actual relative position between the tool and the tool holder, moving the tool within the tool holder until the actual position of the tool relative to the tool holder is equal to a desired position, shrinking the tool holder around the tool, and removing the tool holder and the tool from the alignment device. [0010] The subject invention provides many advantages over conventional tool assembly units by providing a tool assembly unit that rapidly and precisely couples a tool and a tool holder. One of the major advantages is reducing or eliminating the need to measure each tool and tool holder, thereby significantly reducing the inaccuracy that can result from these repetitive measuring operations due to human error. Another advantage is that rod wear does not result in improper positioning of the tool relative to the tool holder, thereby reducing cost by reducing the number of resultant tool assembly units that cannot be used. Furthermore, the tool assembly unit of the present invention permits the heat shrink process to be done quickly to avoid down time when changing tools, thus reducing tool change time and encouraging an efficient assembly operation. BRIEF DESCRIPTION OF THE DRAWINGS [0011] Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: [0012] [0012]FIG. 1 is a perspective view of a tool assembly unit; [0013] [0013]FIG. 2 is an exploded perspective view of an alignment device used in the tool assembly unit of FIG. 1; and [0014] [0014]FIG. 3 is cross-sectional view of the alignment device of FIG. 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0015] Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a tool assembly unit is generally shown at 10 . The tool assembly unit 10 includes a measuring device shown generally at 12 , a heating device shown generally at 14 , and an alignment device shown generally at 16 . A controller 15 controls the various operations of the tool assembly unit 10 . The controller 15 includes a control panel 18 and a display screen 20 . In the disclosed embodiment, a work table 22 is also shown for supporting the tool assembly unit 10 . [0016] The measuring device 12 is a standard tool measuring device such as, for example, a microset unit sold by Tooling Systems Division of Frankenmuth, Mich. The measuring device 12 includes an optical viewer 24 mounted on a vertical tower 26 . The optical viewer 24 in the disclosed embodiment is connected to the controller 15 . In use, the desired length of the assembled tool and tool holder is inputted into the controller 15 which automatically adjusts the optical viewer 24 to the correct height along the tower 26 . In operation, once the tool 36 is correctly positioned with respect to viewer 24 , the correct height is known for that particular desired tool and tool holder assembly. [0017] In another embodiment, the optical viewer 24 is adapted for continuously determining the position of the tool 36 with respect to the tool holder 34 . In addition, the controller 15 may be connected to the viewer 24 and the tool 36 and tool holder 34 such that the optical viewer 24 continuously detects the actual position of the tool 36 with respect to the tool holder 34 and sends an electronic signal to the controller 15 indicating the actual position. In response, the controller 15 compares the actual position with the desired position and moves the tool 36 with respect to the tool holder 34 until the desired position is achieved. [0018] The heating device 14 includes a heater 28 mounted on a slide tower 30 . The position and operation of the heater 28 is controlled by the controller 15 . Although two controllers 15 have been disclosed, it will be appreciated by those of ordinary skill in the art that a single controller or any other type of control unit could be used to perform the operation and positioning of the heater unit and viewer. [0019] With reference to FIG. 2, the alignment device 16 will be described. The alignment device 16 includes a spindle 32 for holding a tool holder 34 . In the preferred embodiment, the tool holder 34 is held within spindle 32 through a vacuum clamp. The tool to be mounted within the tool holder is shown generally at 36 . A push rod 38 is adapted to reciprocate through the spindle 32 and tool holder 34 to engage the shank 40 of tool 36 . The engagement of the rod 38 with the shank 40 may be such that they are removably attached, coupled so that the tool 36 rests on top of the rod 38 or any other suitable means of coupling or mating such that the rod 38 may move the tool 36 within the tool holder 34 to the desired position. [0020] The rod 38 is removably mounted to an adjustable mount 42 . In the disclosed embodiment, the rod 38 is mounted to the mount 42 through an adjustable screw 44 . The rod 38 is removably mounted so that different rod sizes can be used or the rod 38 can be replaced if it becomes worn. However, it should be appreciated that wear of the rod is not important to the proper operation of the present invention since the rod itself is only used as a push rod for positioning the tool 36 with respect to the tool holder 34 and the viewer 24 . This operation will be described in greater detail below. [0021] The mount 42 is connected to an air slide 46 and to an adjustment shaft 48 . In the preferred embodiment, the air slide 46 provides for rapid adjustment and the shaft 48 provides for fine adjustment. The fine adjustment in the disclosed embodiment is achieved through a gear box 50 and an electronic control 52 . System air is controlled through electronic controls 52 , 54 which control pressurized air through air lines 56 . The electronic controls 52 , 54 are coupled to the controller 15 . [0022] A housing top surface is shown at 58 and a mounting bracket is shown at 60 . The top surface 58 and the mounting bracket 60 form the support for supporting the alignment device 16 with respect to the heating device 14 and measuring device 12 . [0023] With reference to FIG. 3, the operation of unit 10 will be described. In operation, the push rod 38 is initially moved to its lowest position. In this position, the push rod 38 can be replaced if necessary. As discussed above, replacement of the push rod may be required if there has been damage to the push rod or undue wear or if a different size push rod is required for a specific mounting operation. The control panel 18 , 20 for controlling the push rod 38 is illustrated schematically. The down button 61 would be engaged to move the push rod 38 down. [0024] After the push rod 38 is down, the tool holder 34 is then placed in the spindle 32 . The vacuum clamp is energized by pushing button 63 on control panel 18 , 20 . This holds the tool holder 34 within the spindle 32 . It is contemplated that a standard vacuum clamp would be employed or any other suitable means of retaining the tool holder 34 within the spindle 32 . [0025] At this point in the operation, if there is an existing tool 36 mounted within the tool holder 34 , i.e., the intent is to replace the tool 36 , the push rod 38 would be raised to touch the bottom of the cutting tool 36 . This would be controlled by the push rod 38 up button 65 . Then either manual measurement of the tool 36 and tool holder 34 would be done or the measuring device 12 would be set at the predetermined dimension for the tool and tool holder. [0026] The heating unit 14 would then be programmed through the controller 15 which in this embodiment is being shown with the same numeric indication as the push rod controller 15 and vacuum control. Again, as indicated above, these various controllers could be a single unit or various units to control the various operations of unit 10 . The controller 15 would initiate heating of the heater 28 and also move the heater 28 into position so that the bore 64 in the heater is positioned over the bore of the tool holder 34 to heat that region and expand it for receipt of the shank 40 of tool 36 . [0027] As illustrated in FIG. 3, the heater slide 30 is mounted through bracket 62 to the spindle assembly 32 of the alignment device 16 . Once the tool holder 34 is properly heated, the heating device 28 will move away from the tool holder 34 and either the existing tool 36 can be removed and a new tool inserted into the bore. Or if it is a first time assembly, a new tool is inserted. The fine adjustment knob 67 is then used to raise or lower the tool 36 to the crosshairs of the optical viewer 30 . Once the tool 36 is properly within the crosshairs of optical viewer 24 , the proper alignment between tool 36 and tool holder 34 has been achieved. The vacuum clamp is then released by pushing vacuum clamp button 63 and the tool holder 36 and tool 34 are removed from the spindle 32 and placed into a cooling rack for complete cooling. [0028] The foregoing detailed description shows the preferred embodiments of the present invention are well suited to fulfill the objects of the invention. It is recognized that those skilled in the art may make various modifications or additions to the preferred embodiments chosen herein to illustrate the present invention, without departing from the spirit of the present invention. Accordingly, it is to be understood that the subject matter sought to be afforded protection should be deemed to extend to the subject matter defined in the appended claims, including all equivalents thereof. [0029] The invention has been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than limitation. It will be apparent to those skilled in the art that many modifications and variations of the present invention are possible in light of the above teachings. Therefore, it is to be understood that the invention may be practiced otherwise than as specifically described within the scope of the amended claims.

4y

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims priority from U.S. Design patent application 29/378,814 filed Nov. 10, 2010, entitled “TIE-DOWN CLIP.” TECHNICAL FIELD [0002] The present disclosure is directed to the field of tent construction and assembly and, more specifically, to a connector plate for simplifying such assembly. BACKGROUND OF INVENTION [0003] Tents have long been used as shelter in many parts of the world. More recently, tents of varying sizes have begun to be used for recreational purposes, such as marquee tents for wedding receptions, outdoor parties, and corporate hospitality events. Smaller high peak frame tents, often used without sidewalls, may be used for tailgating parties, family gatherings, smaller corporate hospitality events, and the like. [0004] Conventionally, tent set-up has been labor-intensive and has required specialized knowledge and/or tools. The assembly of an event tent typically involves spreading the tent fabric across the ground, erecting tent poles and stakes in the ground around the perimeter of the tent, and securing the fabric to the stakes using a combination of tent straps and ropes. For example, the tent fabric may be provided with straps or ropes that are connected to tensioned ratchets and to the stakes, thus creating tension on the tent fabric. [0005] Given that tent construction may require specialized tools and skills, a tool for simplifying the assembly of a tent would be beneficial. Further, constructing a tent without the need for separate stakes would be advantageous. SUMMARY [0006] Provided herein is a connector plate for quickly and easily securing tent guide ropes and/or straps for facilitating a tent's assembly. The connector plate, which is generally planar, includes a base portion, a trunk portion extending longitudinally from the base portion, and a number of branches extending radially from the trunk portion. The base portion has dimensions that are greater in the transverse direction than the longitudinal direction (that is, has a greater width than length) and defines therethrough a slot opening that receives a tent strap. The branches, which may be grouped as oppositely disposed pairs, terminate in geometric shaped end portions, around which end portions a tent guide rope may be wrapped. [0007] A method of assembling a tent using the present connector plate is also provided. A tent fabric is provided with a strap, which is secured through the slot in the base portion of the connector plate. A rope is threaded between branches on a first longitudinal half of the connector plate. The rope is then wrapped around the terminal end of the connector plate (opposite the slot) and between branches on a second longitudinal half of the connector plate. The rope next traverses the trunk of the connector plate and is positioned between a branch and the base portion to anchor the tent fabric. Once the tent is anchored, the rope is wrapped around the base portion to secure the assembly. Finally, the rope is tied to a tent pole or stake to complete the assembly. BRIEF DESCRIPTION OF THE DRAWINGS [0008] A full and detailed disclosure is set forth in the accompanying specification, which makes reference to the appended figures, in which: [0009] FIG. 1 is a perspective view of a connector plate of the present disclosure; [0010] FIGS. 2A through 2E are schematic plan views of various terminal ends, which may be potentially useful with the connector plate of FIG. 1 ; [0011] FIG. 3 is an elevational plan view of the connector plate of FIG. 1 , illustrating a first step in a method of using the same; [0012] FIG. 4 is an elevational plan view of the connector plate of FIG. 1 , illustrating a second step in a method of using the same; [0013] FIG. 5 is an elevational plan view of the connector plate of FIG. 1 , illustrating a third step in a method of using the same; [0014] FIG. 6 is an elevational plan view of the connector plate of FIG. 1 , illustrating a fourth step in a method of using the same; [0015] FIG. 7 is a perspective view of a tent assembly using the connector plate of FIG. 1 ; and [0016] FIGS. 8 and 9 are plan views of alternate embodiments of the connector plate of FIG. 1 . DETAILED DESCRIPTION [0017] Reference is now made to the drawings for illustration of various components of the present connector plate. The connector plate is adapted to connect a tent strap to a guide rope, thereby facilitating tent assembly. While the particular illustrations provided herein are directed to a tent assembly, various elements and embodiments may be equally applicable to coverings constructed using a tarp (regardless of whether they have the structural similarity to a tent). It should be noted that, although the connector plate is shown as having a substantially flat construction residing within a single plane, a non-planar connector plate (for example, a plate having up- or down-turned branches) may instead be employed. [0018] FIG. 1 illustrates a connector plate 2 , which may be constructed of any durable, relatively non-malleable material, such as stainless steel. The connector plate 2 includes a base portion 10 , a longitudinally extending trunk portion 40 , a first pair of radially extending branches 20 , 22 , and a second pair of radially extending branches 30 , 32 . The base portion 10 has dimensions that are greater in the longitudinal direction than in the transverse direction (that is, the base portion 10 has a greater width than length). A slot-shaped opening 16 is defined in a transverse direction through the base portion 10 . The slot 16 receives a tent strap (e.g., 102 , shown in FIGS. 3-6 ). A single slot 16 may be used, as shown, or a pair of slots 16 may be employed, in the event that a pair of tent straps is used. The trunk portion 40 defines a central longitudinally extending region and a central longitudinal axis (shown in dashed lines in FIG. 1 ). [0019] The first pair of branches 20 , 22 is positioned proximate the base portion 10 and between the base portion 10 and the second pair of branches 30 , 32 . A crevice 26 is formed on a first longitudinal half of the connector plate between the base portion 10 and the branch 20 . Likewise, on the second (opposite) longitudinal half of the connector plate 2 , a corresponding crevice 28 is formed between the base portion 10 and the branch 22 . The first pair of branches 20 , 22 may be provided with an irregular edge portion 24 , such as a saw-tooth or serrated edge, proximate the base portion 10 . The irregular edge portions 24 engage a rope ( 100 , shown in FIGS. 3-6 ) threaded around the connector plate 2 . Other types of profiles or surface modifications may be used for irregular edges 24 , such as an undulating surface, a hook-shaped surface, a spiked surface, or a surface treated with a friction-increasing coating. [0020] A second pair of branches 30 , 32 extends radially from the trunk portion 40 , the branches 30 , 32 being oppositely disposed from one another. Crevices 36 , 38 are defined between the second branches 30 , 32 and the first branches 20 , 22 , respectively. The edges of the branches 30 , 32 may be provided with irregular edge surfaces, similarly to the branches 20 , 22 , although such modification is not required. Distal to the base portion 10 is a terminal end 37 of the connector plate 2 , the terminal end 37 being integral with the branches 30 , 32 . As shown, the terminal end 37 is slightly concave for ease of manipulating a rope therearound and is narrower (in a transverse direction) than the base portion 10 (also in the transverse direction). The connector plate 2 may be provided with a straight or convex end portion, if so desired. [0021] As shown in FIG. 2A , the terminal end portion of the branches (e.g., 32 ) possesses a generally triangular geometric shape. The triangular shape is shown in dashed lines in FIG. 2A , noting that the edges are somewhat rounded for ease of manufacturing and use. FIG. 2B through FIG. 2E illustrate alternate geometric shapes that may be employed as the terminal end portions of the branches (e.g., 32 ). In FIG. 2B , a branch 232 possesses an oval or oblong terminal end. In FIG. 2C , a branch 332 is provided with a circular terminus. A branch 432 is provided with a terminal end portion in the shape of a parallelogram, such as a rectangle, in FIG. 2D . FIG. 2E illustrates a branch 532 having a trapezoidal terminal end portion. Other geometric- or organic-shaped terminal ends may be used, as needs or preferences dictate, the previously described drawings being provided merely as examples. [0022] A method of using the connector plate 2 is illustrated in FIGS. 3 through 6 . A tent fabric (not shown) is provided with a strap 102 , which is secured through the slot 16 in the base portion 10 of the connector plate 2 . As a first step shown in FIG. 3 , a user slides the rope 100 between branches 32 , 22 on a first longitudinal half of the connector plate 2 . Said differently, the rope 100 is threaded into the crevice 38 between adjacent branches 22 , 32 . The rope 100 may be threaded from the back of the plate 2 to the front of the plate 2 and on the left longitudinal half of the plate, as shown, or the rope 100 may be similarly positioned on the opposite half of the plate and/or threaded from the front of the plate 2 to the back of the plate 2 . [0023] In a second step shown in FIG. 4 , the rope 100 is then wrapped around the terminal end 37 of the connector plate 2 (opposite the base portion 10 ) and between the adjacent branches 30 , 20 on a second longitudinal half of the connector plate 2 . As depicted, the rope 100 is wrapped over the front of the connector plate 2 and is positioned into the crevice 36 from the back of the connector plate 2 . In the event that the user began wrapping the rope 100 from the front of the connector plate in the previous step, the directionality of the second, holding step would be reversed (front-to-back instead of back-to-front). [0024] As shown in FIG. 5 , the rope 100 positioned between the branches 30 , 20 next traverses the trunk 40 of the connector plate 2 (across the front side of the plate 2 ) and is positioned in the crevice 28 between the branch 22 and the base portion 10 to anchor the tent fabric. The serrated teeth on the irregular edge 24 help to secure the rope 100 in position. [0025] Once the tent awning is anchored, the rope 100 is wrapped around the trunk portion 40 proximate the base portion 10 to secure the assembly, as illustrated in FIG. 6 . The rope 100 is threaded from the crevice 28 around the back of the connector plate 2 , enters the crevice 26 from the back, and is wrapped across the front of the connector plate 2 and back onto itself in the crevice 26 . [0026] Finally, as shown in FIG. 7 , the loose ends of the rope 100 are tied to a tent pole or stake 103 to complete the tent assembly 105 . [0027] Although the connector plate 2 shown and described herein has included branches 20 , 22 and 30 , 32 that are arranged as oppositely disposed pairs, other arrangements are possible. For instance, the branches may be off-set axially from one another, as shown in FIG. 8 , in which like elements are numbered in the “600” series, or may be arranged in an X-shape, as shown in FIG. 9 , in which like elements are numbered in the “700” series. In addition, one or both pairs of branches may be oriented in different plane from the base portion and trunk portion. For instance, the branches may be up-turned or down-turned relative to the base and trunk portions. [0028] Alternately to the method of use described previously, the connector plate 2 may be used in an inverted position, in which the rope 100 being wound around the connector plate 2 is attached to the tent awning material and the strap 102 is connected to a ratcheting device, which itself is secured to a stake in the ground. Yet another variation of use occurs when the rope 100 is attached to the tent awning material and the straps 102 are positioned within the closed doors or windows of two adjacent vehicles, such as trucks or cars. [0029] The preceding discussion merely illustrates the principles of the present connector plate. It will thus be appreciated that those skilled in the art will be able to devise various arrangements, which, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope. Furthermore, all examples and conditional language recited herein are principally intended expressly to be only for educational purposes and to aid the reader in understanding the principles of the inventions and the concepts contributed by the inventor(s) to furthering the art and are to be construed as being without limitation to such specifically recited examples and conditions. [0030] Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents and equivalents developed in the future. [0031] This description of the exemplary embodiments is intended to be read in connection with the figures of the accompanying drawings, which are to be considered part of the entire description of the invention. In the description, relative terms such as “lower”, “upper”, “horizontal”, “vertical”, “above”, “below”, “up”, “down”, “top” and “bottom”, as well as derivatives thereof (e.g., “horizontally”, “downwardly”, etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. Likewise, numerical-based terms, such as “first” and “second”, are used merely for identifying particular components and are not to be construed as limiting the invention to a particular number of components. These relative terms are for convenience of description and do not required that the apparatus be constructed or operated in a particular orientation, unless otherwise indicated. [0032] The foregoing description provides a teaching of the subject matter of the appended claims, including the best mode known at the time of filing, but is in no way intended to preclude foreseeable variations contemplated by those of skill in the art.

4y

This application claims priority to U.S. Provisional patent application Ser. No. 60/052,443, of Sales et al.; filed Jul. 14, 1997, for Common Air Interface incorporated herein by reference. This patent document relates to a common air interface described in a series of patent documents filed concurrently herewith. Related patent documents are: U.S. patent application Ser. No. 09/115,102, filed Jul. 13, 1998, of Soleimani, et al.; for SIGNALING MAINTENANCE FOR DISCONTINUOUS INFORMATION COMMUNICATIONS; U.S. patent application Ser. No. 09/115,098 filed Jul. 13, 1998, of Joshi, et al.; for SYSTEM AND METHOD FOR IMPLEMENTING TERMINAL TO TERMINAL CONNECTIONS VIA A GEOSYCHRONOUS EARTH ORBIT SATELLITE; U.S. patent application Ser. No. 09/115,097, filed Jul. 13, 1998, of Roos, et al.; for MOBILE SATELLITE SYSTEM HAVING AN IMPROVED SIGNALING CHANNEL; U.S. patent application Ser. No. 09/115,096, filed Jul. 13, 1998, of Noerpel, et al.; for SPOT BEAM SELECTION IN A MOBILE SATELLITE COMMUNICATION SYSTEM, now U.S. Pat. No. 6,233,451; U.S. patent application Ser. No. 09/115,101, filed Jul. 13, 1998, of Noerpel, et al.; for PAGING RECEPTION ASSURANCE IN A MULTIPLY REGISTERED WIRELESS TRANSCEIVER; U.S. patent application Ser. No. 09/115,095, filed Jul. 13, 1998, of Joshi, et al.; for IMMEDIATE CHANNEL ASSIGNMENT IN A WIRELESS SYSTEM; and U.S. patent application Ser. No. 09/115,100, filed Jul. 13, 1998, of Roos, et al.; for SYNCHRONIZATION OF A MOBILE SATELLITE SYSTEM WITH SATELLITE SWITCHING, all of which are incorporated herein by reference. BACKGROUND OF THE INVENTION The present invention relates to data transfer or communications, and more particularly to data transfer protocols in communications environments. Even more particularly, the present invention relates to a data link layer protocol in a communication environment, such as a satellite-based wireless network. Wireless telecommunications systems built around earth orbit relays (satellite links) experience a single hop roundtrip propagation delay of approximately 500 milliseconds. Typical implementations of a data link layer protocol employ a “go-back-N” reject protocol with a window size of between one and seven frames. In accordance with the “go-back-N” reject protocol, when a frame is received, feedback is transmitted to a sender indicating that a particular frame was received. When propagation delay is high, such as in satellite systems, this acknowledgement of receipt may lag behind the sender (transmitter) by a substantial number of frames, e.g., 10 or 15. Thus, by the time a defective frame is detected, a substantial number of subsequent frames have already been sent. When a defective frame is detected, a “go-back-N” message is returned instead of a message indicating that a frame was received successfully. This “go-back-N” message signals the sender to resend starting with the defective frame. Unfortunately, a number of successfully sent frames may already have been communicated to the receiver before the “go-back-N” message is received by the sender. Thus, these frames are resent, even though they were already successful sent, thus expending time and bandwidth, both precious commodities in satellite communication environments. Another approach, which is available in typical implementations of data link layer protocols is referred to as selective reject. Selective reject, like “go-back-N” reject provides feedback to the sender regarding each frame that was not successfully received. In the event a frame is not successfully received, a message is sent to the sender indicating the frame not successfully received. The sender then resends only that frame. Thus, if frames 1 , 7 and 10 , by way of example, for a particular transmission are not received successfully, selective reject requires three transmissions to the sender indicating that frames 1 , 7 and 10 need to be resent. This is true whether the rejected frames are discontinuous, as in the example presented, or represent a block of frames, which would commonly be the case if interfering signal momentarily disrupted communications from the sender. In response to these messages, the sender will resend only frames 1 , 7 and 10 . SUMMARY OF THE INVENTION The present invention provides a data link layer protocol approach useful in a communications environment, such as a satellite based wireless network. In one embodiment, the present invention can be characterized as a method for error flow control in a communications system. The method includes steps of receiving a plurality of frames of data; determining in said plurality of frames of data, two or more contiguous defective frames of data, the two or more contiguous defective frames of data being followed by at least one frame of data in said plurality of frames that is not defective; forming a group reject message indicative of a range of the two or more contiguous defective frames; transmitting the group reject message; and receiving replacement frames, the replacement frames corresponding to the two or more contiguous defective frames, wherein said at least one frame that is not defective is not received again in response to the group reject message. BRIEF DESCRIPTION OF THE DRAWINGS The above and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawings wherein: FIG. 1 is a typical satellite communicating system in which teachings of an embodiment of the present invention may be employed; FIG. 2 is a frame diagram showing a first exemplary window of fifteen frames, with frames one through three indicated as lost or detection frames; FIG. 3 is another frame diagram; and is showing a second exemplary window of fifteen frames, with frames twelve through 15 indicated as lost or defective frames; FIG. 4 is a further frame diagram showing a thorough exemplary window of fifteen frames with frames three, seven, and twelve as indicated as lost or defective frames FIG. 5 is an additional frame diagram showing a forth exemplary window of fifteen frames, with frames two through fourteen indicated as lost or defective frames. Corresponding reference characters indicate corresponding components throughout the several views of the drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following description of the presently contemplated best mode of practicing the invention is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. Referring first to FIG. 1, shown is a block diagram of a satellite communications system 10 , including a wireless transceiver 12 , a satellite relay station 14 (or satellite link) and a gateway/network 16 . When the gateway/network 16 sends information to the wireless transceiver 12 via the satellite link 14 , as mentioned above, a delay of about 540 milliseconds is introduced in propagating information from the gateway/network 16 to the satellite link 14 and from the satellite link 14 to the wireless transceiver 12 . As a result, prior art “go-back-N” reject protocol approaches operate in a less than optimal manner in that by the time a defective frame is received at the wireless transceiver 12 and the wireless transceiver 12 determines that the defective frame includes one or more errors, several other frames have already been transmitted by the gateway/network 16 . As a result, even though these frames may be error free, once a “go-back-N” reject protocol message has been sent from the wireless transceiver 12 to the gateway/network 16 , incurring further delay, and resulting in the transmission of further frames by the gateway/network 16 in the meantime, the gateway/network 16 must go back to the defective frame, and retransmit it, and all frames that follow it. As a result, a great deal of unnecessary retransmission is required. Another approach to reject protocol implementation in a satellite system is selective reject. As mentioned above, however, selective reject allows the wireless transceiver to signal the gateway/network 16 to resend any frame. Thus, if frames 4 , 7 and 10 in a group of frames are determined by the wireless transceiver 12 to be defective, the wireless transceiver 12 can signal the gateway/network 16 to resend frames 4 , 7 and 10 using three separate selective reject protocol messages. Similarly, if frames 1 , 2 and 3 of the group of frames are defective, three separate selective reject protocol messages are sent by the wireless transceiver 12 to the gateway/network 16 in accordance with the selective reject approach. In the “go-back-N” procedure, on detection of a defective frame, the wireless transceiver 12 sends acknowledgement to all frames that are received in sequence, and requests retransmission of the defective frame and all subsequent frames. Subsequent frames are not acknowledged until they have been successfully resent, even if there were no errors in their original transmission. As mentioned above, this wastes time, bandwidth, and delays receipt of the entire group of frames. Selective reject is used by the data link layer entity to request retransmission of single frames. The selective reject approach may or may not incorporate the acknowledgement in accordance with whether a particular bit is sent within a control channel. Each selective reject condition is cleared upon successful receipt of the particular frame for which retransmission is requested. A data link layer entity may transmit one or more selective reject frames, each containing a different frame identifier. Frames that may have been following (or between) the frames indicated by the selective reject (with selective rejects) will not be retransmitted as a result of the gateway/network 16 having received the selective reject. Thus, by reducing the number of needlessly retransmitted frames, selective reject improves the efficiency of the datalink, while recovering missing frames. To fully realize this advantage, however, the wireless transceiver 12 having missed a frame, i.e., received a defective frame, should buffer subsequent frames until the missing frame is received. This generally imposes additional buffering and house keeping requirements on the receiving side. One limitation of the selective reject error recovery procedure is that it requires the wireless transceiver 12 to send a selective reject frame for each lost or defective frame. In some cases, selective reject is more advantageous, and in others “go-back-N” is a more appropriate approach. In implementation, it becomes difficult for the data link layer to make a decision as to which one of theses two approaches should be used in a given case. Due to the limitations of selective reject and built inefficiency of “go-back-N”, the desired solution for a recovery in satellite networks is to use a novel approach, as described below, referred to herein as group reject. Group reject provides, in a single frame, a request for retransmission of a range of lost frames with acknowledgement. In this scheme wireless transceiver 12 need not decide whether to use “go-back-N” or selective reject. In the examples discussed below, the wireless transceiver 12 can send a single reject message with an indication of retransmission of a range of lost frames or with acknowledgement of a single lost frame, frame without acknowledgement. The gateway/network 16 , upon receipt of a group reject frame, updates its window and retransmits all requested frames. (Note that the group reject approach described herein works equally well when the wireless transceiver 12 is the sender and the gateway/network 16 is the receiver, as when the wireless transceiver 12 is the receiver and the gateway/network 16 is the sender, the latter at which is described herein. Referring next to FIG. 2, shown is a schematic representation of a group of frames, with defective or lost frames being indicated as open squares and successfully received frames being indicated as cross-hatched squares. If the wireless transceiver 12 detects an error in consecutive frames near the beginning of a group of frames, as shown, in accordance with selective reject protocol, the wireless transceiver 12 would generate a selective reject message for each of the lost frames. If the datalink layer utilizes the group reject approach in accordance with the embodiment described herein, it sends a single group reject frame for retransmission of the range of frames one through three, shown. Referring next to FIG. 3, another example is shown in a schematic diagram wherein a group of frames successfully received are indicated with cross-hatched squares and a group of defective or lost frames are indicated as open squares. A darkened square indicates a frame not ever received. Thus, shown, if the wireless transceiver detects an error at the end of its receive buffer, the wireless transceiver issues a group reject for recovery of the lost frames, in this case, frames twelve, thirteen, fourteen and an acknowledgement up to frame 11 . Referring next to FIG. 4, a diagram is shown in which cross-hatch squares indicating received frames, and open squares indicating erroneous or lost frames. Darkened frames indicate frames yet to be received. If the wireless transceiver detects an exception error or between a start and an end of receive buffers, and if this reception error involves more than one frame, the wireless transceiver can request a retransmission of the frames, in the example shown, frames three, seven and twelve. The wireless transceiver would acknowledge up to frame 2 in the instances shown. Referring next to FIG. 5, a diagram is shown in which cross-hatched squares are received frames, open squares represent erroneous or lost frames, and darkened squares indicate frames that are yet to be received. If the wireless transceiver detects an exception between the start and end of its receive buffers, in the case with the group reject only one frame is required to recover each group of lost frames. In the examples shown, frames two through fourteen could be requested with a single group reject message. In the example shown above, a window size of 15 frames is selected in the data link layer. This means that the gateway/network 16 can send fifteen messages without waiting for acknowledgement. In addition, only one layer three message can be transmitted by the data link layer. The use information in the TCH 3 is seven bytes so a layer three message of size 120 (15×8) can be transmitted without waiting for acknowledgement. With a given round-trip delay of 540 milliseconds (270×2) and 150 milliseconds processing time in the wireless transceiver, the sender should expect response from the receiver at the end of 690 milliseconds (540=150) or about 700 milliseconds. This means the sender should be able to receive a response from the receiver at the end of the fourth message of a subsequent window. Since a window has a size of 15 frames, this is sufficient to assure that acknowledgement is received before the end of the subsequent frame. In the case of SMS services, the maximum size of a SMS message is 256 bytes. This message requires 37 (256/7) frames to transmit. With a window size of 15 frames (messages), the sender will stop transmitting at the end of 15 frames (if the receiver does not send any response). The receiver shall respond within the first four messages of the subsequent window. In the event the gateway/network 16 does not receive a response from the receiver by the end of the 15th message of the subsequent window, the gateway/network concludes that something is in error at the receiver, and responds accordingly by, for example, retransmitting all of the frames of the window. While the invention herein disclosed has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention set forth in the claims.

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BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to an apparatus to hold a spring collet for a machining process. 2. Description of the Prior Art The manufacturing facility of our present time must have the highest efficiency and quality control yet at the same time costs of operation must be kept to a minimum, all in an effort to remain competitive in a market that is now more ruthless due to the ever present and expanding global economy of scale. Down time of production machines critical to the manufacturing process is an expensive and wasteful matter causing production managers and manufacturing executives to forever update production equipment and machinery. Rotating machine tools have been at the foundation of the production manufacturing business. The lathe is one such piece of rotating machinery which has been in use since very early times of manufacturing. The lathe is typically a machine tool with a horizontal spindle for shaping a workpiece by gripping it in a holding device and rotating it under power against a suitable cutting tool for turning, boring, facing or threading primarily cylindrical objects. Chucks are used as the holding device. The chuck is a device standard to most lathes for holding the workpiece rigid, usually by means of adjustable jaws or set screws. The collet is a further refinement to the holding device being a split, coned or tapered sleeve for holding generally small circular workpieces inside the chuck. An earlier chucking mechanism is shown in Duphily at U.S. Pat. No. 2,430,761 where the chuck is typical operating in cooperation with a series of radially placed jaws to hold a workpiece. U.S. Pat. No. 2,597,712 being another similar chucking mechanism issued to Drissner utilizes a chuck mountable on a spindle for cooperation with a series of jaws. A later edition is seen in U.S. Pat. No. 3,625,530 to Parsons being entitled "Collet Activating Device" including two concentrically arranged tubular members movable axially and annularly relative to the other. All existant devices consist of variously designed chucks that must be removed, rebored and reinstalled to adapt to the various collets available being at considerable down time cost and causing inefficiency on the production line. Today's manufacturing facility demands a superior collet attachment apparatus that will reduce down time. The invention presented in this application meets and exceeds this criteria. SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a collet attachment apparatus enabling most lathe type machine tools to be adaptable to existing chucks. It is a further object through a collet attachment apparatus to eliminate removal of the chuck and existing hydraulics for insertion of different sized collet holders. It is a further object to provide a collet attachment apparatus having improved safety and accuracy through locking of the collet holder during operation. It is a further object to provide a collet attachment apparatus readily adaptable to most existing hydraulic/pneumatic drawbars. It is a further object to provide a collet attachment apparatus allowing a collet holder to be changed in 15 minutes compared with the present minimum time of 8 hours, practically reducing production downtime significantly. More specifically, the present invention is a collet attachment means for rotating a machine tool having a rotating drawbar means comprising, in combination a collet holder means for holding a collet; a nose collet adapter chuck means for location within a forward and inside diameter of a master chuck for holding said collet holder means; a rear spindle draw tube adapter means for location with a rearward inside diameter of a hydraulic actuator drawbar for fastening to said hydraulic actuator bar, whereby said drawbar means passes through said rear spindle draw tube adapter means annularly on an inside diameter causing axial movement to said collet within an inside diameter of said nose collet adapter chuck means; a first lock ring means to define axial distance boundaries of said drawbar means for further determining the amount of pressure exerted on a collet holding cavity; a second lock ring means coordinating with said first lock ring means to define said axial distance boundaries of said drawbar means for further determining the amount of said pressure exerted on said collet holding cavity; a draw tube nut means secured to said rearward most point of said drawbar tube for controlling the said axial movement of said collet by rotating said draw tube nut means in a clockwise or counterclockwise direction allowing said collet to be removed or inserted from or into said collet attachment means. In accordance with the provisions of the Patent Statues, I have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of the invention, reference may be had to the accompanying drawings, in which: FIG. 1 is a side cross sectional view in part of a collet attachment apparatus; FIG. 2 is a detailed chuck end view of a collet attachment apparatus; FIG. 3 is a detailed view of a chuck end of a collet attachment apparatus; FIG. 4 is a detailed view of the rear and opposite chuck end of a collet attachment apparatus. FIG. 5 represents a detailed view of an engaging pin. FIG. 6 is a detailed view of a window allowing for adjustment of a knurled spring-faced lock ring. FIG. 7 is a cross sectional view of a second knurled spring faced lock ring. FIG. 8 is a cross sectional view of a first knurled spring faced lock ring. DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings, FIG. 1 and FIG. 3 depict a collet attachment apparatus 10 mounted to a machine tool 8, preferably a lathe, for securing collet 32, where preferably collet 32 is a spring type having a tapered external surface 34 and an opposite internal threaded surface 38 for mating to a drawbar 30. A collet holder 12 engagingly encompasses the collet 32. A nose collet adapter chuck 18, which attaches to master chuck 48 engagingly encompasses the collet holder 12. Master chuck 48 is standard to all machine lathe type tools. The collet holder 12 is an annular configuration machined and ground on its inside diameter to fit collet 32 having a plurality of collet holder bores 14 a-f for accepting a plurality of collet holder bolts 16 a-f for attachment to nose collet adapter chuck 18. Positioning screws 20 a-d in combination with tapped cavities 22 a-d permit radial adjustment of collet holder 12 for indications of collet 32 on a workpiece 44 within 0.0002 TIR (total indicator reading). Nose collet adapter chuck 18 secures to master chuck 48 through a plurality of nose collet adapter chuck bores 24 a-c and corresponding nose collet adapter bolts 26 a-c. Nose collet adapter chuck 18 has a plurality of equidistant flat linear chordal surfaces 49 a-c for accepting pressure from a plurality of corresponding radially sliding gripping jaws 50 a-c minimizing movement of drawbar 30. Collet 32 as viewed from FIG. 2 has collet holding cavity 33 for holding machining member 44 by lateral movement of drawbar 30 which releases pressure or causes pressure between a tapered internal surface 46 of collet holder 12 and a tapered external surface 34 of collet holder 32. Collet 32 has a central cylindrical section 36 having a laterally located plurality of key slots 40 for accepting a drive pin 28, functioning to lock the collet 32 during its rotational mode. Collet slots 42 a-c cut radially and equidistantly into collet 32 creating the spring effect at collet holding cavity 33. Rear spindle draw tube adapter 56 is attached to a hydraulic or pneumatic actuator 54 by a plurality of bores 84 a-f and bolts 82 a-f. Hydraulic or pneumatic actuator 54 is a standard component to all lathe type machine tools. Rear spindle draw tube adapter 56 encompasses drawbar 30 which moves laterally when actuated by hydraulic or pneumatic actuator 54. Bushing 58 is provided to minimize surface wear on drawbar 30 during lateral movement. Hydraulic or pneumatic actuator 54 is attached to head stock 52, which encompasses a gearing mechanism (not shown) for regulation of rotations per minute (r.p.m.) of machine tool 8. Generally a foot pedal (not shown) is used to actuate hydraulic or pneumatic actuator 54 which by being secured to hydraulic actuator drawbar 86 shown in FIG. 1 and FIG. 6 causes hydraulic actuator drawbar 86 to move either laterally left 100 or laterally right 102 as machine tool 8 is viewed in FIG. 1. When hydraulic actuator drawbar 86 moves laterally left 100, it causes drawbar 30 to move likewise laterally left 100 and conversely, when hydraulic actuator drawbar moves laterally right 102, it causes drawbar 30 to move laterally right 102. When drawbar 30 moves laterally left 100, compressive pressure is exerted on external surface 34 of collet holder 32 causing the closure of collet holder 32 on workpiece 44. When drawbar 30 moves laterally right 102, compressive pressure is relieved from external surface 34 of collet holder 32 from workpiece 44. During this lateral movement process, rear spindle draw tube adaptor 56 will contact second knurled spring faced lock ring 66 during the lateral left 100 movement of drawbar 30 stopping said lateral movement. Likewise, when drawbar 30 moves laterally right 102 when rear spindle draw tube adapter 56 contacts first knurled spring faced lock ring 60. The said lateral movement ceases. During this process of lateral movement either to the left or to the right, collet attachment apparatus 10 is in a static and non-rotational mode. The rotational mode of collet attachment apparatus 10 occurs when an operation is desired on workpiece 44. This rotational motion occurs to collet attachment apparatus 10 by causing drawbar 30 and likewise all attached components including collet 32 to rotate. First knurled spring faced lock ring 60 has a plurality of threaded bores 76 a-f located radially and equidistantly on drawbar 30 for acceptance of a plurality of set screws 77a and 77b making it possible to lock first knurled spring faced lock ring 60 into a plurality of laterally located machine lock slots 74 after first knurled spring faced lock ring 60 is rotated clockwise or counterclockwise to adjust the diameter of collet holding cavity 33 by exerting or releasing pressure thereon between tapered internal surface 46 of collet holder 12 and tapered external surface 34 of collet holder 32. Helical spring lock washers 59 may be located around drawbar 30 between first knurled spring faced lock ring 60 as viewed from access window 67 and second knurled spring faced lock ring 66 to cushion the opening process of spring collet 32. A releasably locking member 61 consists of an engaging pin 64, release lever 62, lock lever spring 63 and release lever pivot pin 65, which operate to lock drawbar 30 during rotation and prevent any relative rotation of drawbar 30. Engaging pin 64 is engaged into or out of lock slots 74 by depression or release of release lever 62. Lock lever spring 63 prevents release lever 62 from disengaging from lock slots 74 during rotational mode of collet 32. Second knurled spring faced lock ring 66 locks to drawbar 30 via a plurality of threaded bores 78 a-f for acceptance of a plurality of set screws 79a and 79b after adjustment of the diameter of collet holding cavity 33 and coordinates with first knurled spring faced lock ring 60 to define the axial or lateral movement distance boundaries of drawbar 30. Knurled draw tube nut 68 locks to drawbar 30 through a plurality of threaded bores 80 a-d for acceptance of a plurality of set screws (not shown). Knurled draw tube nut 68 rotates clockwise or counterclockwise for controlling the axial movement of collet 32 allowing collet 32 to be removed or inserted into collet holder 12. Coolant drain openings 75 allow coolant (various cutting oils) to exit from draw bar 30.

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CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of copending application, U.S. patent application Ser. No. 07/283,689, filed Dec. 13, 1988, now U.S. Pat. No. 4,865,399 which is a continuation-in-part of U.S. patent application Ser. No. 07/053,221, filed May 22, 1987, now U.S. Pat. No. 4,828,335, which is a continuation-in-part of U.S. patent application Ser. No. 06/764,162, filed Aug. 9, 1985, now U.S. Pat. No. 4,668,023, which is a continuation-in-part of U.S. patent application Ser. No. 06/702,765, filed Feb. 19, 1985, now U.S. Pat. No. 4,673,226. BACKGROUND OF THE INVENTION The present invention relates generally to vehicle anti-lock brake systems and, more particularly, to a low pressure accumulator assembly for such a system wherein the accumulator is adapted to receive and temporarily store fluid during pressure reduction phases of the anti-lock control operation. Braking a vehicle in a controlled manner under adverse conditions such as rain, snow, or ice generally requires precise application of the brakes by the vehicle driver. Under these conditions, or in panic stop situations, a driver will often apply excessive brake pressure, thus causing the wheels to lock such that excessive slippage between the wheels and the road surface takes place. Wheel lockup conditions can lead to loss of directional stability and, possibly, uncontrolled vehicle spinout. In a continuing effort to improve the operational safety of vehicles, many companies have been involved in the development of anti-lock braking systems. While typically such systems are adapted to control the braking of each braked wheel of a vehicle, some systems have been developed for controlling the braking of only a portion of the braked wheels. Examples of prior art anti-lock brake systems are disclosed in U.S. Pat. Nos. 3,515,440; 3,731,979; 3,870,376; and 3,880,474. Generally, prior art anti-lock brake systems include a central control unit for monitoring the speed of the controlled wheels to determine the deceleration of the controlled wheels. When the brakes of the vehicle are applied and the wheel deceleration of the monitored wheels exceeds a predetermined deceleration threshold, indicating that there is wheel slippage and the wheels are approaching a lockup condition, the central control unit functions to control the application of hydraulic pressure through a control valve means to the associated brakes to prevent lockup of the controlled wheels. Typically, the anti-lock brake system includes means for cyclically reducing and reapplying pressure to the associated brakes to limit wheel slippage to a safe level while continuing to produce adequate brake torque to decelerate the vehicle as desired by the driver. While some systems utilize a separate hydraulic pump as the means for reapplying pressure, other systems, such as disclosed in U.S. Pat. No. 4,418,966, do not require the use of a separate hydraulic pump. In controlling the application of pressure to selected wheel brakes, many systems utilize a low pressure accumulator which is operative to temporarily receive and store brake fluid during pressure reduction phases of the anti-lock operation. The low pressure accumulator typically maintains fluid stored therein at a predetermined minimum pressure determined by a compression spring acting on an accumulator piston, generally in the range of 30-60 p.s.i. This minimum pressure represents the lowest pressure to which the controlled brakes can be reduced during anti-lock operation. However, it has been found that, in certain braking situations, it is necessary to reduce the controlled pressure below this minimum pressure in order to achieve the desired control. SUMMARY OF THE INVENTION The present invention concerns a unique accumulator assembly for a vehicle anti-lock brake system which receives brake fluid during pressure reduction phases of the anti-lock operation, and maintains brake fluid stored therein at or near zero pressure. Thus, if necessary, fluid pressure to the controlled wheel brakes can be reduced to near zero pressure. Such low pressure reduction has been found to be desirable when attempting to free up a disc brake rear wheel of a light truck braking on a very low mu surface such as ice. In these situations, the natural drag provided by the continuous engagement of the disc brake pads and rotor require that pressure be reduced to near zero pressure in order to free up a locked rear wheel. The accumulator assembly of the present invention is capable of achieving such pressure reduction. In addition, the accumulator assembly includes means which, after braking of the vehicle, applies a predetermined pressure above zero pressure to the brake fluid stored therein to return the fluid to the brake system. In the preferred embodiment of the invention, the accumulator assembly includes a piston slidably disposed within a housing and cooperating with the housing for defining a variable volume reservoir for receiving brake fluid during pressure reduction phases of the anti-lock operation. The piston is normally spring biased to a position wherein the reservoir is at a minimum volume. The accumulator assembly also includes an axially shiftable plunger which is coupled to compress the spring during anti-lock operation such that the spring exerts no force on the accumulator piston. The accumulator piston is then free to slide axially within the housing as fluid is introduced into the reservoir, and fluid is stored therein at essentially zero pressure. In the preferred embodiment of the invention, the plunger remains in the unactuated position until anti-lock operation has been initiated to reduce pressure, at which time it is hydraulically shifted by means of fluid pressure supplied by the vehicle master cylinder. When the brake pedal is released, the spring returns the plunger and piston to their initial positions, thus forcing the fluid in the accumulator reservoir back into the brake system. The accumulator assembly of the present invention is especially useful in vehicle anti-lock brake systems which do not utilize a separate pump to apply additional pressure to the wheel brakes, such as the pumpless anti-lock system disclosed in U.S. Pat. No. 4,790,607. Other advantages of the invention will become readily apparent to one skilled in the art from reading the following description in conjunction with the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram illustrating a vehicle anti-lock brake system which utilizes the accumulator assembly of the present invention; FIG. 2 is a sectional view of a control valve of the type schematically shown in FIG. 1, with the components of the accumulator shown in position prior to the introduction of any fluid into the accumulator reservoir; and FIG. 3 is a fragmentary sectional view, similar to FIG. 2, but showing the relative positions of the accumulator components after fluid has been introduced into the accumulator reservoir. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates a schematic diagram of a vehicle anti-lock brake system 10 including a control valve 10 which utilizes an accumulator assembly 11 constructed in accordance with the present invention. In particular, the control valve 10 includes those components located within the area defined by the dashed line 10a. Prior to discussing the details of the accumulator assembly 11, the basic components and general operation of the anti-lock brake system will be briefly reviewed. A more detailed explanation of the control system and the control valve utilized therewith can be found in U.S. Pat. Nos. 4,673,226; 4,668,023; 4,790,607; and 4,828,235, and allowed U.S. patent application Ser. Nos. 07/283,360 and 07/283,689, all of which are herein incorporated by reference. The anti-lock brake system illustrated in FIG. 1 is installed on a vehicle having a hydraulic braking system consisting of a brake pedal 12 coupled to operate a dual reservoir master cylinder 14. When the vehicle operator depresses the brake pedal 12 to brake the vehicle, the master cylinder 14 supplies pressurized hydraulic fluid from a front reservoir 14a through a hydraulic line 16a and from a rear reservoir 14b through a hydraulic line 16b to a conventional combination valve 18. The combination valve 18 includes a first output line 18a adapted to supply hydraulic fluid at a predetermined pressure to actuate the vehicle front brakes 19a and 19b and a second output line 18b which supplies fluid at a second predetermined pressure to actuate the vehicle rear brakes 20a and 20b. The combination valve 18 functions to maintain the fluid pressures to the front and rear brakes in approximate proportion to the weight distribution over the front and rear axles during braking of the vehicle. The anti-lock control valve 10 is provided with a normally open isolation valve 22 connected between the line 18b and a line 24 which supplies pressurized fluid to the rear brakes 20a and 20b. The isolation valve 22 is solenoid-operated and is closed in the event an impending rear wheel lock up condition is detected. When closed, the valve 22 will hold the pressure in a line 24 at a relatively constant level and thus will prevent any further increase in pressure in the line 18b from being supplied to the line 24. The anti-lock control valve 10 also includes a normally closed dump valve 26 connected between the line 24 and a line 27 which is connected to the accumulator assembly 11 of the present invention. The accumulator assembly 11 includes a variable volume fluid reservoir 28 for receiving fluid from the rear brake system during time periods when the rear brake pressure is reduced. In particular, when the isolation valve 22 has been closed and the pressure held in the line 24 continues to cause excessive slippage of the rear wheels, the dump valve 26 is selectively opened to direct fluid into the accumulator reservoir 28 to reduce the brake pressure in the line 24 and prevent lock up of the rear brakes. After the brake pedal 12 has been released, the isolation valve 22 is opened and the fluid in the accumulator reservoir 28 can be returned to the line 24 through a check valve 29. A check valve 31 is connected across the isolation valve 22 between the lines 18b and 24 and provides for fluid flow from the line 24 to the line 18b when the pressure in the line 24 is greater than the pressure in the line 18b. Thus, when the brake pedal is released and the isolation valve is opened, higher pressure fluid in the line 24 can return to the line 18b through both the isolation valve 22 and the check valve 31. The operation of the isolation valve 22 and the dump valve 26 is controlled by a computer control module 30. The isolation valve 22 and the dump valve 26 are solenoid operated valves having solenoids 22a and 26a which can be connected to the computer control module 30 by means of electric lines 32 and 34 respectively. In order to determine whether the vehicle operator is in the process of braking the vehicle, the computer control 30 is connected to a brake light switch 36 by a line 38 to monitor whether the brake pedal 12 is depressed. The computer control module 30 is also connected by a line 42 to a speed sensor 40 which monitors the average speed of the vehicle rear wheels by sensing the rotation of the rear differential ring gear (not shown). The computer control module 30 is further connected to a differential pressure switch 44 by a line 46. The differential switch 44 provides two separate functions. As discussed in detail in above-identified U.S. Pat. No. 4,828,335, when the system is in the anti-lock mode, the switch 44 is used to monitor the differential pressure across the isolation valve 22 in order to determine when it is desirable to release the anti-lock mode and return the braking system to the normal operating mode. Secondly, when the vehicle is not in the anti-lock mode and the vehicle is in the normal braking mode, the switch 44 is used to monitor the condition of the dump valve. The operation of the anti-lock brake system illustrated in FIG. 1 will now be summarized. Basically, the system monitors the rear wheel speed and deceleration and, during braking of the vehicle, functions to control the application of hydraulic pressure to the vehicle rear brakes via the control valve 10 in order to prevent a lock up condition of the rear wheels. In the event a rear wheel slip condition is detected, indicating that the rear wheels are approaching a lock up condition, the control module 30 closes the isolation valve 22 to hold the pressure in the line 24 at its present value. If, after the isolation valve 22 has been closed, the rear wheel deceleration rate exceeds a predetermined amount, the dump valve 26 can be selectively opened to reduce pressure in the line 24 to prevent lock up of the rear wheels. When the dump valve 26 is selectively opened, fluid will be directed into the accumulator reservoir 28 via the line 27. In some instances, after pressure has been dumped to reduce rear wheel slip and correct an impending lock-up condition, it is desirable to re-apply additional pressure to the rear brakes to increase braking of the rear wheels. This is accomplished by momentarily opening the isolation valve 22 to permit the higher pressure fluid in the line 18b to be supplied to the line 24. The specific conditions under which additional pressure is reapplied to the rear brakes is discussed in detail in U.S. Pat. No. 4,790,607. The present invention is specifically concerned with the construction of the accumulator assembly 11. In accordance with the present invention, during anti-lock operation, fluid supplied to the accumulator reservoir 28 will be maintained at or near zero pressure. In most prior art accumulators, the pressure is typically maintained at a pressure which is a function of the associated spring constant and is generally in the range of 30 to 60 psi. However, it has been discovered that, with certain braking systems and under certain braking conditions, it is sometimes desirable to reduce rear brake pressure to an amount less than 30 to 60 psi. For example, in vehicles such as light pick-up trucks wherein the rear wheels are provided with disc brakes, and the vehicle is stopping on a relatively low mu surface such as ice, it has been found that, in order to free up a rear wheel which has been locked under these conditions, the brake pressure to the rear wheel often must be reduced to near zero. With prior art accumulators, it is only possible to reduce the brake pressure to the level maintained by the associated spring. The accumulator assembly 11 schematically shown in FIG. 1 is capable of maintaining brake fluid during anti-lock operation at or near zero pressure. As shown in FIG. 1, the accumulator assembly 11 includes an axially shiftable plunger 28a which is normally biased toward the left (as viewed in FIG. 1) by a compression spring 28c to force a slidable piston 28b toward an end wall of the accumulator housing 28d. In this position, the piston 28b and the housing 28d cooperate to define an accumulator reservoir at minimum volume. In accordance with the present invention, when the brake system enters the anti-lock mode and fluid is dumped into the accumulator reservoir 28, means are provided for shifting the plunger 28a toward the right (as viewed in FIG. 1) for compressing the spring 28c against the right wall of the housing 28d. In these instances, the plunger 28a will exert no axial force on the piston 28b and the piston will be free to shift axially toward the right to increase the volume of the accumulator reservoir 28 without exerting any substantial force on the fluid contained therein. In the preferred embodiment of the invention, the plunger 28a is hydraulically shifted by means of master cylinder fluid pressure in the line 18b supplied to the accumulator assembly through an orifice 28f and adapted to exert a force on an end face 28e of the plunger 28a. During non braking conditions, the spring 28c urges the plunger 28a toward the left as shown in FIG. 1 such that end face 28e of the plunger 28a is seated against the end wall of the accumulator housing, and the piston 28b is urged toward the left to maintain the accumulator reservoir at minimum volume. When brake pressure is applied, the resultant axial force exerted on the plunger 28a will be a function of the area of the end face 28e exposed to the pressurized fluid. When the plunger 28a is in the position shown in FIG. 1, this area corresponds to the area of the orifice 28f. The size of the orifice 28f and the spring constant of the spring 28b are chosen such that, under non anti-lock braking conditions, the axial force exerted by the spring 28c is greater than the opposite hydraulic force, thus maintaining the plunger in the position as shown. However, when the system enters the anti-lock mode and fluid is initially dumped into the accumulator reservoir 28, the piston 28b and the plunger 28a will be forced to the right to partially compress the spring 28c, thus exposing the entire end face 28e of the plunger 28a to the fluid pressure in the line 18b. In these instances, the resultant hydraulic force is sufficient to compress the spring 28c such that the spring no longer exerts any force on the accumulator piston 28b. The accumulator piston will then be free to shift to the right to increase the volume of the accumulator reservoir 28 without exerting any pressure on the fluid stored therein. When the brakes are released, the spring 28c will urge the plunger 28a and the piston 28b back to their original positions, and will force any fluid in the accumulator reservoir 28 back into the rear brake line 24 through the check valve 29. Referring now to FIG. 2, the specific construction of the accumulator assembly 11 of the present invention will now be discussed in detail. FIG. 2 illustrates the control valve 10 having a structure which, except for the new accumulator design, is similar to the control valve described and illustrated in allowed U.S. Pat. No. 4,828,335. Thus, in the present application, while the overall structure of the valve will be briefly reviewed, only the accumulator assembly will be discussed in detail. The valve 10 includes a one-piece valve body 60 having an inlet 61 adapted to be connected to the line 18b of FIG. 1 and an outlet 62 adapted to be connected to the line 24 of FIG. 1. The valve body 60 is provided with a plurality of internal openings formed therein for receiving various components of the valve. For example, an opening 60a is adapted to receive the isolation valve assembly 22, an opening 60b is adapted to receive the dump valve assembly 26, and an opening 60c is adapted to receive the differential switch assembly 44. The components of the accumulator assembly 11 are mounted within an opening 60d and a smaller opening 60e which is connected to the opening 60d. The various components of the control valve are interconnected within the valve body 60 by a series of internally formed passageways, as discussed in detail in U.S. patent application Ser. No. 07/053,221. The isolation valve assembly 22 includes a normally open ball valve 65, while the dump valve assembly 26 includes a normally closed ball valve 66. Under non anti-lock conditions, brake fluid is supplied directly from the inlet 61 to the outlet 62 through a series of passageways as discussed in detail in U.S. Pat. No. 4,828,335. When the system enters the anti-lock mode, the isolation ball valve 65 is closed to block fluid flow between the inlet 61 and the outlet 62 and prevent any further increase in pressure to the rear brakes. Thereafter, if the system determines that pressure to the rear brakes should be reduced, the dump ball valve 66 can be selectively pulsed open to permit fluid to flow past the ball valve 66 downwardly through a central passageway 67 formed in the dump valve assembly and into the accumulator reservoir 28. The preferred embodiment of the accumulator assembly 11, shown in FIG. 2, includes a generally cup-shaped slidable piston 70 (corresponding to the piston 28b of FIG. 1), a helical coil compression spring 72 (corresponding to spring 28c of FIG. 1), and an end plug 74. The piston 70 is slidably mounted within the cylindrical opening 60d and is urged toward the left end of the opening 60d by means of the spring 72 which is compressed between a spring seat 75 and the end plug 74. An O-ring 76 is mounted within an outer annular groove formed in the piston 70 and sealingly engages the inner cylindrical wall of the opening 60d. A rubber boot 78 is secured to the plug 74 and projects into the opening 60d, and is provided to accommodate air pressure changes in the space to the right of the piston 70 as the piston 70 is moved to the right. The accumulator assembly also includes an actuating plunger 80 (corresponding to the plunger 28a of FIG. 1) which is slidably mounted within the smaller cylindrical opening 60e and is retained therein by means of a plug 82 threaded into the outer end of the opening 60e. The inner end of the plunger 80 extends through a cylindrical opening 70b formed in the end wall of the piston 70 and has an innermost end 80a formed in a generally semi-spherical manner which extends into a cup-shaped portion of the spring seat 75. An O-ring seal 81 is provided within the cylindrical opening 70b and sealingly engages the outer surface of the plunger 80. The plug 82 is provided with a transverse passageway 82a which communicates with a passageway 83 formed in the valve body 60 and connected directly to the inlet 61 to receive master cylinder fluid pressure from the line 18b through a filter 84. In addition, the plug 82 is provided with an axially extending passageway 82b which connects the passageway 82a to an outer end face 80b of the plunger. The passageway 82b is provided with a restriction 82c to limit fluid flow therethrough. The outer end face 80b of the plunger is provided with a cylindrical opening having a seal 85 mounted therein. When the accumulator spring 72 is extended as shown in FIG. 2, the outer end face 80b of the plunger 80 is urged against the inner face of the plug 82 to cause the seal 85 to sealingly engage the end plug 82 around the entire periphery of the outlet end of the passageway 82b. The outlet end of the passageway 82b is sized of a diameter D1 (shown in FIG. 3) such that, during normal braking operation, the fluid pressure exerted on the seal 85 is insufficient to axially shift the plunger 80 and compress the spring 72. Thus, in these circumstances, the spring 72 will be extended and will continue to maintain the plunger 80 in its leftmost position, at which point the accumulator reservoir is at minimum volume. In this situation, the end face of the piston 70 will be slightly spaced from the inner end wall of the reservoir by a distance L, as shown in FIG. 2. However, once the brake system has entered the anti-lock mode and has caused fluid pressure to be dumped into the accumulator reservoir 28, the piston 70 will begin to move toward the right with the spring seat 75, and will begin to compress the spring 72. At this point, the spring seat 75 will no longer force the plunger 80 against the plug 82. The fluid pressure exerted on the plunger 80 is then sufficient to shift the plunger 80 axially toward the right to disengage the seal 85 from the end face of the plug 82. At this point, the entire end face 80b of the plunger 80, having a diameter D2 as shown in FIG. 3, will be exposed to the master cylinder fluid pressure. With this additional area, sufficient additional force is exerted on the plunger 80 to compress the spring 72, as shown in FIG. 3, such that the spring will exert no axial force on the piston 70. Thus, the piston is free to shift to the right as fluid is introduced into the reservoir 28, and the fluid contained in the reservoir will be maintained at or near zero pressure. When the brake pedal is released, fluid pressure in the line 18b is no longer sufficient to overcome the force exerted by the spring 72, and the spring will urge the plunger 80 and the piston 70 back to their unactuated positions shown in FIG. 2. This causes the fluid in the accumulator reservoir 28 to be returned to the brake system via the check valve (shown in FIG. 2 as a one way lip seal 29a), while the fluid used to shift the plunger 80 is returned through the passageway 82b. An annular lip seal 86 is located around the inner end of the plug 82 and provides a path, in addition to the passageway 82b, for returning fluid to the passageway 82a when the plunger 80 is moved from its actuated position (shown in FIG. 3) to its unactuated position (shown in FIG. 2). When the plunger is in the unactuated position, and pressurized fluid is present in the passageway 82a, the fluid will exert a force on the seal 86 which tends to compress the seal 86 in an axial direction toward the plunger 80. This causes the fluid located in an annular space 87 about the outer end of the plunger 80 to become pressurized. To reduce the axial force exerted on the plunger 80 by the fluid in the annular space, a second lip seal 88 is located around the outer end of the plunger 80. Thus, when the seal 86 is compressed, the seal 88 will be compressed in a similar manner, thereby reducing the effect of any axial force exerted by the fluid in the space 87 on the plunger 80. The accumulator assembly of the present invention has been explained and illustrated in its preferred embodiment. However, it will be appreciated that various modifications may be made to the accumulator assembly without departing from the spirit of the present invention. For example, while the preferred embodiment of the invention utilizes fluid pressure supplied by master cylinder as a means for axially shifting the plunger to compress the accumulator spring, other means could be used. Also, while the accumulator has been described herein for use with a pumpless anti-lock system, it will be appreciated that the accumulator can be used in a more conventional, pumped anti-lock system.

4y

BACKGROUND OF THE INVENTION The invention relates generally to liquid gauging systems of the type that use ultrasonic echo ranging to determine liquid levels. More particularly, the invention relates to methods and apparatus for discriminating true and false echoes to improve accuracy of such systems. It is well known to use ultrasonic echo ranging to determine liquid levels. Common applications include fuel gauging systems in fuel tanks. Typically, one or more ultrasonic transducers are disposed near the bottom of a liquid tank or container. The transducers emit ultrasonic pulses on the order of 1 megahertz frequency towards the liquid surface. Each ultrasonic pulse is reflected at the fuel/air interface and returns in the form of an echo pulse. The echo pulses are then detected by the same transducer that transmitted the pulse or are detected by a different sensor. The detection sensor typically produces an electrical output signal that corresponds to receipt of the echo. Thus, the round trip time from pulse emission to echo detection corresponds to the distance of the liquid surface from the sensors. Characterization data of the fuel tank can thus be used with the level detection data to determine liquid quantity in the tank. Ultrasonic liquid level detection in fuel tanks such as are used on aircraft is complicated by several factors. First, water tends to accumulate in the bottom of the fuel tanks, particularly on aircraft that fly at higher altitudes over extended distances, such as, for example, transoceanic commercial flights. Water at the bottom of the tank can present a fuel/water interface that reflects ultrasonic energy in the form of false echoes back to the transducers when such transducers are disposed at or near the tank bottom. Such false echoes can be mistaken for true fuel level echoes and thus give a false indication of fuel level and quantity. Another problem that arises in fuel tanks is the presence of air bubbles. Aircraft manufacturers have run tests that indicate the presence of air bubbles, under some conditions large in size and quantity, due to fuel slosh and vibration under various flight scenarios. Air bubbles present a fuel/air interface that can reflect ultrasonic energy in the form of false echoes. These echoes can also be misinterpreted as false liquid level readings. Accordingly, the objective exists for apparatus and methods for discriminating true and false echoes in ultrasonic liquid level sensing systems. Such apparatus and methods should be capable of distinguishing true echoes from false echoes such as may be caused by air bubbles and other false interfaces. SUMMARY OF THE INVENTION In response to the aforementioned objectives, the present invention contemplates a method for discriminating true and false echoes in an ultrasonic liquid gauging system comprising the steps of: a. transmitting an ultrasonic pulse toward the liquid surface; b. detecting true and false echoes and converting the echoes into electrical signals after a predetermined delay interval after transmission; and c. identifying a true echo from a false echo based on energy of the echoes. The invention also contemplates apparatus for carrying out the described method, which in one embodiment is an apparatus for discriminating true echoes from false echoes in an ultrasonic liquid gauging system, comprising: means for producing electrical representations of an echo sequence received after an ultrasonic transmission, wherein the echo sequence contains one or more returned echoes that may be a true or false echo; and means for determining returned echo energy, wherein echo energy is a factor used to distinguish a true echo from a false echo. These and other aspects and advantages of the present invention will be readily understood and appreciated by those skilled in the art from the following detailed description of the preferred embodiments with the best mode contemplated for practicing the invention in view of the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A-1C are a series of graphs showing in a simplified manner transmit/receive ultrasonic signals and corresponding echo profiles as typically occur in fuel level sensing applications; FIGS. 2A, 2B and 2C is a detailed functional block diagram of a fuel gauging system that embodies the teachings of the present invention; and FIGS. 3A, 3B and 3C is an flow chart for the operational sequence and control functions of the fuel gauging system shown in FIGS. 2A, 3B and 2C according to the invention. DETAILED DESCRIPTION OF THE INVENTION With reference to FIGS. 1A-1C, I show in a simplified representative manner typical signals that occur during ultrasonic liquid level sensing, such as in an aircraft fuel tank. Although the invention is described herein with respect to an ultrasonic fuel level sensing system, those skilled in the art will readily appreciate that the invention can advantageously be used in other ultrasonic echo ranging applications. Furthermore, while the preferred embodiment of the invention is realized in the form of a microprocessor based control system, the invention can also be implemented without a microprocessor controller using digital signal processing techniques well known to those skilled in the art. In FIG. 1A, the ultrasonic acoustic signatures for a typical transmit and receive pulse pair are shown. The transmit pulse (TR) is assumed to start at time=t 0 and may be, for example, a 1 megahertz frequency signal produced by a conventional transducer such as part no. 2-11178 available from Zevex. The transmit pulse is directed towards the liquid surface. After a delay period t d which represents that time required for the transmitted ultrasonic pulse to reach the surface, be reflected back towards the transducer and be detected by the transducer, the transducer now serves as an ultrasonic receiver and converts the echo, EC, into an amplitude variant analog signal that corresponds to the strength of the received echo. In practice, of course, the received echo has a somewhat more complicated profile. This does not have an appreciable effect, however, on the usefulness of the present invention. For example, immediately after the transmit period ends at about time t 1 , a large output signal is produced by the transducer (not shown) because of transducer ringing and close-in reflections. As is well known, this initial echo-like response can be excluded from the valid echo profile by including an appropriate blanking time that disables the signal processing circuits until after time t 1 . FIG. 1B illustrates the transmit and receive signal envelopes under conditions in which there is no detected bubble or water/fuel interference. The echo envelope EC' can be produced simply by demodulating the amplitude variant high frequency ultrasonic echo EC into a corresponding amplitude variant low frequency by suitable rectification and filtering of the carrier frequency. As shown in FIG. 1C, however, the actual echo profile will include spurious noise spikes or false echoes, FE. These false echoes may be caused by air bubbles, for example. If water is at the bottom of a fuel tank such that a fuel/water interface is present between the transducer and the surface fuel/air interface, another false echo will be produced, although such an echo will tend to be less random than air bubbles. The fuel/water echoes will not be fixed, however, because of accumulation of water in the tank, for example. Thus, an actual echo profile for a single transmit/receive cycle will include a number of echoes, one of which is the true echo from the liquid surface and any number of false echoes that may have peak amplitudes comparable to the true echo. The variable nature of the false echoes due to the dynamic conditions of a fuel tank in an aircraft makes conventional peak amplitude based discrimination of true and false echoes inaccurate and unreliable. Furthermore, conventional pulse width measurement also is unsuitable because the echo envelope of such false echoes is somewhat unpredictable. Time variable threshold detection techniques suffer from the need for repetitive transmissions and also the unpredictability of the true and false echo envelopes. In accordance with an important aspect of the present invention, true and false echoes in an echo profile are discriminated by determining the relative or actual energy of the received echo signals. Because the echo energy detection technique relies primarily on a determination of the total energy (or substantial portion of the total energy) of the received echoes, the ability to discriminate true and false echoes is less sensitive to the individual echo envelope characteristics. Although echo energy detection can, if desired, be used each transmit/receive cycle for locating the true echo, I have found that such frequent measurements are not necessary for all applications. In some cases, the energy detection technique can be used to verify that the first echo received after the blanking time (i.e. the second temporal echo received after the transmission period ends) is in fact the true echo. Thus, a simple amplitude based detection scheme can be used each transmit/receive cycle, with the energy based verification technique being used at a less frequent rate, for example every five transmit/receive cycles. The echo energy detection concept of the present invention is particularly well suited to discriminating false bubble and water/fuel echoes because the amount of energy reflected by the air/fuel interface at the liquid surface is significantly greater than the energy reflected by air bubbles and a water/fuel interface. With reference next to FIGS. 2A, 2B and 2C (hereinafter collectively referred to as FIG. 2), a functional block diagram is provided of a suitable fuel gauging system that embodies the teachings of the present invention. Those skilled in the art will readily appreciate that the invention can be practiced with many different circuit configurations, and that in particular the circuitry that embodies the basic functions of the invention can be added to conventional fuel gauging systems and control circuits used with such systems. Examples given herein of types of circuits that can conveniently be used to realize the functional blocks are intended to be illustrative and should not be construed in a limiting sense. The functional blocks can be realized in many different ways in both analog and digital formats. In the ultrasonic fuel gauging system (UFGS) of FIG. 2, the UFGS 10 includes several main functional sections. These include a controller section 12, a signal conditioning section 14 and a multiplexing section 16. This description of the circuit as having three main functional sections has no particular significance, but rather is simply used for ease of explanation and clarity. Those skilled in the art will readily appreciate that the main circuit sections are interconnected and that, in many cases, components associated with a particular section in this description could just as easily be associated or described with reference to a different section. The sectional approach is used herein because the present invention can generally be viewed as embodied in circuitry associated with the signal conditioning circuit in terms of modifications that are suitable, for example, with conventional UFGS systems, along with appropriate software changes to implement the described functions. However, the embodiment of the invention illustrated in FIG. 2 should not be construed in a limiting sense because the implementation of an echo envelope energy detection process can be realized in varied ways. The controller section 12 includes a main CPU or microprocessor 20. Conventional devices such as 8OC31BH available from Intel Corp. can be used. The speed and control power needed from the CPU 20 will be determined in part, of course, by how many sensors are to be interrogated and how frequently data will be collected. These requirements will vary with each application, but in most cases the basic device identified herein will be suitable. The controller 20 can be programmed in a conventional manner as described in the manufacturer's specification, as is well known to those skilled in the art. The functions carried out by the software in order to realize the present invention are included in the functional flow chart in FIGS. 3A, 3B and 3C which will be described later herein. The controller 20 operates from a main clock provided from a crystal oscillator 22, in combination with an operating program stored in a non-volatile program memory 24. The crystal oscillator 22 also provides a clock input to echo counters 26 through an enable logic gate 28. The oscillator 22 also provides a clock input to a frequency divide and select circuit 30. The frequency divide and select circuit 30 functions in a conventional manner to divide down the oscillator frequency to a frequency for operation of the ultrasonic transducers. For example, the transducers may operate at a frequency of 1 megahertz. A burst length control signal (BURST) 32 (for convenience, signals and signal lines are treated herein as one in the same--no separate reference numeral is used in the drawings to distinguish a signal from the conductor that carries that signal) from the microprocessor 20 can be used to adjust the transmit frequency based on such factors as temperature of the liquid and anticipated target range. For example, a longer transmit burst is typically used for farther target ranges (high liquid levels) while shorter bursts are typically used for shallow targets. The burst length control signal from the microprocessor 20 can thus be used to dynamically change the burst duration for each transducer. It should be noted at this time that the embodiment illustrated in FIG. 2 shows only one ultrasonic sensor. It is very common, however, to use a large number of sensors, particularly in cases where the fluid container has an irregular configuration or when high accuracy is required, for example. The system of FIG. 2, of course, is designed to accommodate a large number of sensors, such as, for example, by time multiplexing. Thus, it is useful in most cases to provide the controller 20 with the capability to adjust the burst duration (and frequency) depending on which transducer is being activated during a particular cycle. At the beginning of each transmit cycle, the microprocessor sends a transmit (XMIT) signal 34 that serves as a trigger signal to a blanking circuit 36, a variable pulse generator circuit 38, and a counter latch 40. The blanking circuit 36 produces an inhibit signal that disables operation of an echo amplifier 42 for a period of time following the transmit burst. This operation prevents the amplifier from saturating due to ultrasonic energy received during transducer ringing and backscatter. The amount of time delay will be determined by the burst length. Thus, the blanking circuit 36 receives an input control signal 44 from the data select circuit 30, which control signal sets the blanking time duration. The blanking circuit 36 can be conveniently realized, for example, in the form of a one-shot having a controllable variable pulse width. The XMIT signal also triggers the variable burst circuit 38. This circuit can also conveniently be realized in the form of a variable pulse width one-shot. The circuit 38 effectively enables a gate 46 that passes the high frequency burst signal from the frequency divide circuit 30 through to a filter/amplifier circuit 48 for a period of time determined by the duration of the signal from the variable burst circuit 38. The XMIT signal 34 also triggers the counter latch 40. In this case, the counter latch is conveniently realized in the form of an R-S flip flop that is set by the XMIT pulse and reset by a signal generated by the first return echo after blanking. The latch 40 output is used as an enable signal for the oscillator clock 22 pulses to the counters 26. Thus, the counters are enabled at the beginning of the XMIT pulse (i.e. the beginning of a transmit/receive cycle) and count the time delay until receipt of the first echo following the blanking time. The microprocessor reads the counter 26 data 50 and clears the counters after each cycle via a clear signal 52 (those skilled in the art will appreciate that the counters can in fact be a single counter or several counters chained together.) The high frequency burst signal is filtered and amplified as appropriate by the filter circuit 48 and then connected to the transducer T or transducers for the current transmit cycle via a demultiplexer (DMUX) circuit 54. The DMUX circuit is basically an addressable switching circuit that connects the drive signal to the selected transducer T. The demultiplexer circuit receives address commands from the microprocessor in a conventional manner and decodes the addresses so that the drive signal is input to the correct transducer for the current transmit/receive cycle. A transmit/receive switch 56 under control of the microprocessor may be provided between the transducer and the demultiplexer to isolate inactive transducers from noise during each transmit/receive cycle. When echoes are received at the transducer T, the transducer converts the acoustic energy into corresponding electrical signals and sends the echo signals to the echo amplifier 42 via a multiplexing circuit 58. The multiplexing circuit 58 operates similarly to the DMUX circuit 54 in that it is an addressable switching device that connects a selected transducer(s) output to the echo amplifier. (Note that in FIG. 2 the address control lines from the microprocessor to the MUX and DMUX circuits are not shown for clarity and convenience.) The amplified echo output from the amplifier 42 is then rectified by a rectifier circuit 60. In operation, the amplifier 42 and rectifier 60 together convert the high frequency acoustic echo signals, such as signal EC in FIG. 1A, into a dc variable echo envelope, such as the signal EC' in FIG. 1B, in effect demodulating the amplitude modulated high frequency echo signal. As previously stated, during each transmit/receive cycle the echo profile typically will contain a number of echoes, one of which is the true echo and false echoes. All of the echoes in an echo profile of a transmit/receive cycle are demodulated by the amplifier 42 and rectifier 60. The analog echo envelope profile is input to a flash analog-to-digital converter (A/D) 62 that digitizes the echo profile at a preferably high sampling rate, for example, twice the burst frequency of the ultrasonic pulses. The rising edge of the first echo envelope is also used to trigger a level detector 64 which produces a trigger output that resets the echo latch 40 thereby disabling the counters 26. The counters 26 thus count the elapsed time between start of the transmit pulse and detection of the first echo that exceeds the threshold of the detector 64. The digitized echo profile for the transmit/receive cycle is then stored in a temporal manner in a memory device 66 which may conveniently be realized in the form of a dual port RAM controlled by the microprocessor 20. Thus the data position in the memory 66 corresponds to the time of detection of the echo. Data can be written through one port of the memory on data lines 68, and read out by the microprocessor 20 on data lines 70. This configuration permits very fast access to the echo profile by the microprocessor. Under instruction of the main program in memory 24, the microprocessor then determines the true echo and the round trip time to receipt of that echo as an indication of fluid level above the transducer that produced the particular echo profile analyzed. This data can then be stored by the microprocessor in a data memory device 72, which may include a video memory for visual display of the data. The microprocessor may also send the data to a peripheral device or other controller via a serial port 74. The microprocessor 20 can also be programmed in a conventional manner to adjust the gain of the amplifier 42 as a function of the expected range of the true target, since echo strength decays as the target distance increases. Gain adjustment can be controlled, for example, by a standard automatic gain control circuit (AGC) 76. In the specific embodiment of FIG. 2, the first echo received back after the blanking period is initially assumed to be the true echo. This is typically the case, for example, in fuel level sensing systems. Thus, the counters 26 are triggered in response to the first echo. However, as explained hereinbefore, false echoes can be received such as due to air bubbles or fuel/water interfaces. In such circumstances, the first echo back after blanking may not be the true echo. In accordance with the invention, the microprocessor is configured to determine the echo energy for echo envelopes that exhibit maximum peak amplitudes during a transmit/receive cycle. The microprocessor further determines which echo has the maximum energy. When the maximum energy echo has been identified, its temporal location can be determined. If the maximum energy echo occurred at the same time as the first echo that disabled the echo counters 26, then the first echo is confirmed as the true echo. If the maximum echo energy occurred at a different time than the first echo, then the maximum energy echo is considered to be the true echo. The false echo resolution of the first echo can also be confirmed by determining the energy content of the first echo and verifying that the energy level is too low for a true echo from the fluid surface. Further verification can be accomplished by using a time domain window after a true echo position has been determined. In other words, once a true echo is identified, subsequent true echoes can be expected to occur within a specific time window around the previous echo. In cases where the first echo is typically the true echo, the verification process can be performed at a slower rate that every transmit/receive cycle. For example, the echo energy determination can be performed every five transmit/receive cycles, or at some other suitable interval. With reference to FIGS. 3A, 3B and 3C (hereinafter collectively referred to as FIG. 3), a suitable control sequence for the microprocessor 20 is shown in a flow diagram. In this case, the echo energy determination is made every five transmit/receive cycles. At step 100 a transmit/receive cycle is initiated and one or more transducers are selected through the multiplexer switch (102). In the example of FIG. 3, transducer #1 is selected for the described cycle. If the current cycle is the first cycle, then at 104 the transmit burst length and echo amplifier gain are set at default values determined by expected echo characteristics. At step 106 the echo counters 26 are cleared or reset and at step 108 the transmit pulse is sent and the counters are enabled and the blanking pulse is generated. A maximum range clock is used to determine at step 110 whether a maximum time period has elapsed after which no valid echo could be received. After the maximum echo range period expires, for example 2 milliseconds, the counters 26 are read at step 112. If the counters read less than 2 milliseconds then the controller 20 knows that an echo was detected. If no echo was detected the controller branches at 115 to steps 114, 116 and 118 and then back to step 106 for a new transmit pulse. Steps 114, 116 and 118 are used to incrementally increase the transmit burst length and/or gain of the echo amplifier 42 until an echo is detected as indicated by the state of the counters 26. After an echo is detected, the controller stores the echo count in memory at step 120. Note that step 120 is also reached if no echo is received after maximum gain and burst length have been attempted. At step 122 the controller determines if, in this case, five transmit/receive cycles have been completed, either with five echoes detected or some number of echoes less than five detected and the balance including the counter value for max burst and gain attempts. After five samples have been stored in memory, at step 124 the controller calculates the average range for the five detected echoes (range being a function of the counter time measurements.) Keep in mind that at this point the five samples are for the first detected echo after the blanking period. These first five echoes are not necessarily known or verified to be true echoes yet. At step 126 the controller 20 stores the average range in a memory location. In addition to performing the averaging function after five samples are received, the microprocessor 20 at step 128 commands another transmit burst at the last burst length and gain value known to have produced an echo detection. The entire echo profile received over this verification transmit/receive cycle period is stored in the dual port memory 66 at step 130. At step 132 the microprocessor 20 scans the stored echo profile and locates the echo peaks among the various echo envelopes. After determining the higher peak echoes, the system calculates the energy of each of the high peak echoes. In this case, echo energy is calculated by adding the echo amplitude values for a plurality of time intervals around the time that the echo peak occurred. This process is facilitated in the described embodiment because the digitized data directly corresponds echo amplitudes with discrete time intervals in the echo envelope. For example, if an echo peak is detected at 200 microseconds, echo amplitude values at one microsecond intervals, for example, on either side of the 200 microsecond peak are added together. The samples are added until the echo amplitudes fall below a selected threshold level. This total then corresponds to the total energy of the echo. This process is repeated for each echo envelope that exhibits a peak amplitude above a selectable threshold. The echo exhibiting the maximum energy or area under the envelope curve (see FIG. 1B, for example) is identified as a true echo, and at step 134 the microprocessor determines the time at which the true echo was received. At step 136 the time occurrence of the maximum energy echo is compared with the time occurrence of the average first echo that was detected at step 126. If the two time events correspond, then the microprocessor accepts the first echo as a true echo (step 138.) If the two time events do not correlate, then the microprocessor accepts the maximum energy echo as the true echo(step 140.) The system then returns to the start of the process and interrogates the next transducer sensor(s) in the system array. The invention thus provides an ultrasonic liquid level sensing system that uses an improved echo discrimination technique to separate true echoes from the liquid surface from false echoes such as are produced by air bubbles and non-surface interfaces, such as a water/fuel interface in a fuel tank. The echo discrimination technique is based on determination of echo energy, which produces a more reliable and accurate discrimination than amplitude based or pulse width based techniques that rely on time variable thresholds. Although the described embodiment of the invention includes a blanking period to force the system to ignore the transducer ringing and backscatter after transmit, the system could be operated to receive the entire post-transmit echo profile (other useful information can in some cases be extracted from the initial echo.) In such a case, the system would ignore the initial echo data in searching for the maximum energy echo and would trigger the counters 26 as a function of the second received echo. Also, while the described embodiment uses digital conversion and storage of the echo profiles to facilitate echo energy determination, echo energy could also be determined in an analog fashion, such as, for example, with the use of CCD arrays that can store analog signals. While the invention has been shown and described with respect to specific embodiments thereof, this is for the purpose of illustration rather than limitation, and other variations and modifications of the specific embodiments herein shown and described will be apparent to those skilled in the art within the intended spirit and scope of the invention as set forth in the appended claims.

4y

BACKGROUND OF THE INVENTION The present invention relates to a mechanism for the drive of a tool spindle in a rotating indexing manner. A mechanism for the drive of a tool spindle is the subject of U.S. Pat. No. 4,606,682. In the '682 patent, the tool spindle is connected, through a universal joint, to the connecting rod of a reciprocating drive constructed in the form of an eccentric drive. The tool spindle is surrounded by a guide sleeve, and a straight-line guide is provided between guide sleeve and tool spindle. A worm wheel is disposed on the guide sleeve and a helical guide is provided between the worm wheel and the guide sleeve. The worm wheel is in engagement with a worm which is driven by a motor as a result of which the tool spindle performs an indexing movement. The guide sleeve is in turn articulated on the connecting rod of a further eccentric drive which is connected to the reciprocating drive through a drive chain. If the tool spindle performs reciprocating axial movements which the guide sleeve held fast, the tool of the tool spindle performs purely linear movements. On the other hand, if the guide sleeve is put into reciprocating axial movement by the further eccentric drive, then, as a result of the helical guide, the tool spindle additionally performs a rotary movement which leads to a helical movement of the tool. Since the two eccentric drives are adjustable with regard to their eccentricity, it is possible to vary the pitch of the helical movement continuously. A disadvantage of the '682 patent is that it is extremely difficult to adapt the two eccentricities of the eccentric drives to one another so that the desired pitch of the helical movement results precisely. In a further tool-spindle drive disclosed in DE-OS 33 14 524, a worm wheel is mounted on the tool spindle through a straight-line guide. The worm wheel is again in engagement with a worm, the shaft of which is axially displaceable. The axial displacement of a worm shaft is caused by means of a hydraulic motor which is controlled depending on the reciprocating drive for the tool spindle. If the tool spindle performs a reciprocating axial movement, the worm shaft is simultaneously moved backwards and forwards axially so that the tool spindle performs a helical movement The pitch of the helical movement can be varied depending on the direction and amplitude of the reciprocating axial movement of the worm shaft. A disadvantage of the '524 patent is that it is practically impossible to synchronize the two axial movements with one another with the necessary accuracy in order to obtain the desired pitch of the helical movement. A further tool-spindle drive mechanism is the subject of U.S. Pat. No. 4,695,209. The mechanism comprises a guide sleeve which is connected on the one hand to a tool spindle and on the other hand to a worm wheel for rotation therewith through, in each case, a helical guide. The two helical guides have the same pitch but in opposite directions. A first rocking lever is in engagement with the tool spindle and extends substantially at right-angles thereto, which rocking lever is articulately connected to an articulated lever which extends substantially parallel to the tool spindle. Articulated on this articulated lever is a second rocking lever which extends parallel to the first rocking lever and is in engagement with the guide sleeve. The one rocking lever has a pivot point fixed to the frame, which pivot point is displaceable along this rocking lever. The pivot point of the other rocking lever, which is fixed to the frame, is not adjustable. If the position of the displaceable pivot point is altered, the leverage is altered in the one rocking lever. The foregoing results in a variation in the pitch of the helical movement of the tool spindle which is not proportional to the variation in the position of the pivot point. A further disadvantage is that the ends of the rocking levers move over circular paths and so the lines of action of the transmission forces vary continuously, which is unfavorable for the whole stability, the bearing loading and hence for the tooth accuracy which can be achieved. It would be highly desirable to improve the mechanism of the kinds mentioned above so as to achieve a linear adjustment of the pitch of the helical movement. The foregoing object is achieved by way of the present invention by the provision of a two-part sliding loop with a sliding swivel joint between the two members, the rocking lever, as one member, only transmits linear movements to the other member and this sliding swivel joint can be displaced and located along the two members so that the pitch of the helical movement can be altered. Thus, a simple and very accurate manner of adjustment of the pitch of the helix of the workpiece to be produced results with a simultaneous simpler and more robust construction of the drive, which also renders possible a high stroke frequency. The pivot point of the rocking lever which is fixed to the frame is not adjustable in its position. BRIEF DESCRIPTION OF THE DRAWINGS Examples of embodiment are explained in more detail below with reference to the drawings. FIG. 1 shows the perspective view of a first example of embodiment; FIG. 2 shows a perspective view of a modification of the first example of embodiment; FIG. 3 shows the perspective view of a second example of embodiment; FIG. 4 shows the perspective view of a third example of embodiment; FIG. 5 shows a perspective illustration of the third example of embodiment supplemented by a possibility for adjustment; FIG. 6 shows the perspective view of a fourth example of embodiment; and FIG. 7 shows a perspective view of a fourth example of embodiment in order to explain its mode of operation better. DETAILED DESCRIPTION In the example of embodiment according to FIG. 1, the tool spindle 1, which carries the tool 2 at its end, is set in a reciprocating axial movement by a reciprocating drive. The reciprocating drive consists of a driving motor 3 which sets a crank disc 4 in rotation, on which a connecting rod 5 is articulated eccentrically. The eccentricity of this articulation can be adjusted through an adjusting motor 6. At its other end, the connecting rod 5 is articulated on a first rocker arm 7 which is rigidly connected to the rotary shaft 8. This rotary shaft 8 is mounted in the bearing member 9 fixed to the frame. Connected thereto for pivoting with it is a second rocker arm 10 which extends parallel to the first rocker arm 7 which supports a pivoting and sliding joint 11 in a bearing, which joint in turn supports the upper portion of the tool spindle 1 in a bearing. Thus, on actuation of the reciprocating drive, the tool spindle performs reciprocating axial movements. The tool spindle 1 is made in two parts, the upper part 1.1 being connected to the lower part 1.2 through a thrust bearing 12. This thrust bearing 12 secures the lower part 1.2 in relation to the upper part 1.1 in the axial direction but permits a rotary movement of the lower part 1.2 in relation to the upper part 1.1 supported in the joint 11. A helical guide 13, as is known in the art, is rigidly mounted on the lower part 1.2 of the tool spindle 1 and engages in a helical guide 14 of a worm wheel 15. This worm wheel 15 is held against axial movement. Worm wheel 15 is in engagement with a worm 16 which is provided on a worm shaft 17. This worm shaft 17 is in communication with a driving motor 19 through a sliding sleeve 18. The rotating indexing motion of the tool spindle 1 is produced through the driving motor 19, the sliding sleeve 18, the worm shaft 17, the worm 16 and the worm wheel 15, the helical guide 14 of which is in engagement with the helical guide 13 of the lower part 1.2 of the tool spindle 1. If the worm wheel 15 is held fixed during the reciprocating axial movement of the tool spindle 1, the tool spindle 1 performs a rotary movement at the same time because of the helical guides 13, 14 of the lower part 1.2. The extent of this rotary movement depends on the pitch of the helical guides 13, 14. Thus, the tool performs a helical movement, the pitch of which is determined by the pitch of the helical guides 13, 14. In order to be able to alter the pitch positively or negatively, a rocking lever 20.1 is rigidly connected to the shaft 8, which rocking lever is preferably arranged at right-angles to the rocker arms 7, 10 and comprises an arm at each side of the shaft 8. Extending substantially parallel to this rocking lever 20.1 is a displacement member 21.1 which supports the worm shaft 17 at its lower end for rotation but not for axial displacement. Disposed between the rocking lever 20.1 and the displacement element 21.1 is a sliding swivel joint 22.1. In the example of embodiment illustrated, this sliding swivel joint 22.1 consists of a two-part sliding block, of which the sliding-block parts 23.1 and 24.1 are connected to one another for rotation about an axis 25.1. The axis of rotation 25.1 extends at right angles to the rocking lever 20.1 and to the displacement element 21.1. Cooperating with the sliding swivel joint 22.1 is an adjusting spindle 26 which can be coupled to an adjusting motor 27 so that the sliding swivel joint 22.1 can be adjusted along the rocking lever 20.1 and the displacement element 21.1. Cooperating with the sliding-block part 24.1 is a locking device 28 whereby the sliding-block part 24.1 can be locked to the displacement element 21.1. Thus, the rocking lever 20.1, the sliding swivel joint 22.1 and the displacement element 21.1 form a sliding coupling consisting of two members, wherein the reciprocating rotary movement of the rocking lever 20.1 is converted into a reciprocating axial movement of the worm shaft 17, the amplitude of which is dependent on the distance of the axis of the shaft 8 from the axis 25.1 of the sliding swivel joint 22.1. This axial movement of the worm shaft 17 is transmitted, as a rotary movement, via the worm 16 to the worm wheel 15 and hence as an additional rotary movement to the lower part 1.2 of the tool spindle 1. This additional rotary movement is superimposed on the rotary movement which results in consequence of the helical guides 13, 14. According to whether the sliding swivel joint 22.1 assumes a position above or below the axis of the shaft 8, the rotary movement caused by the helical guide 14 is thus increased or reduced. If the sliding swivel joint 22.1 is at the height of the shaft 8, the additional rotary movement is equal to zero, that is to say the rotary movement performed by the tool spindle 1 during the axial movement corresponds precisely to the rotation caused by the pitch of the helical guides 13, 14. In the modified embodiment shown in FIG. 2, the conditions are the same as in the form of embodiment shown in FIG. 1 with the difference that guides 13.1 and 14.1, which are straight-line guides and not helical guides, are provided between the worm wheel 15 and the lower part 1.2 of the tool spindle 1. In this embodiment, if the sliding swivel joint 22.1 is at the height of the shaft 8, the tool spindle 1 only performs reciprocating axial movements but not rotary movement (pitch of the helical movement infinite). On the other hand, if the sliding swivel joint 22.1 is displaced upwards or downwards and locked to the displacement member 25.1 by means of the locking device 28, the tool spindle 1 performs a rotary movement during its axial movement, the pitch of the resulting helical movement of the tool 2 being smaller, the greater the distance of the sliding swivel joint 22.1 from the shaft 8. In the following embodiments to be described below, the parts which are the same have the same reference numerals as the parts in FIGS. 1 and 2. In the embodiment shown in FIG. 3, the connecting rod 5 driven by the crank disc 4 acts on the two-part rocking lever 20.2 which is supported for rotation about a fixed position or the frame by the shaft 8 which in turn is supported by the bearing member 9.1 fixed to the frame. At the opposite end to the connecting rod, the two-part rocking lever 20.2 supports the sliding swivel bearing 11 which supports a cranked lever 32 which in turn supports the tool spindle 1 secured axially via a pivot bearing 33. The tool spindle 1 comprises a straight-line guide 13.1 which cooperates with a corresponding straight-line guide of a guide sleeve 31 which surrounds the tool spindle 1. On the outside, this guide sleeve 31 comprises a helical guide 13 which is guided in a corresponding helical guide 14 of the worm wheel 15. The guide sleeve 31 is supported for rotation in a displacement plate 30 but held against axial displacement in relation to this. The displacement plate 30 is secured against rotation but can move in the direction of the axis of the tool spindle 1. It extends substantially parallel to the two-part rocking lever 20.2. Extending between the rocking lever 20.2 and the slide plate 30, at right angles to these, is a displacement element 21.2. This displacement element has, at the top, a sliding-block member 23.2 which is connected, through a pivot bearing 25.0, to the displacement element 21.2. The axis of rotation, which extends at right angles to the locking lever 20.2 and to the displacement element 21.2, is designated by 25.2. The lower end of the displacement element 21.2 is likewise constructed in the form of a sliding block 24.2 which can be locked to the slide plate 30 by means of a locking device 28. Furthermore, acting on the displacement element 21.2, a spindle 26 whereby, with the locking device 28 released, the displacement element 21.2 can be displaced along the rocking lever 20.2 and the displacement plate 30. If the crank assembly gives the rocking lever 20.2 a rocking motion about the shaft 8, this rocking motion is converted, via the bearing 11, the lever 32 and the bearing 33 into a reciprocating axial movement of the tool spindle 2. If the displacement element 21.2 is in a position in which the axis of rotation 25.2 of the swivel joint 25.0 is in the vertical plane of the axis of the shaft 8, the spindle 1 performs an axial movement on which no rotary movement is superimposed. On the other hand, if the displacement element 21.2 is in a position to the right or left of the shaft 8, the rocking motion of the rocking lever 20.2 is converted into a linear upward and downward movement of the displacement element 21.2 and hence of the displacement plate 30 and of the guide sleeve 31. Thus, with the worm wheel 15 locked, the axial movement of the guide sleeve 31 is converted, via the inclined guides 13, 14 and the straight-line guide 13.1 into a rotary movement of the tool spindle 1. The pitch of the resulting helical movement of the tool 2 depends on the pitch of the helical guides 13, 14 and on the distance of the displacement element 21.2 from the shaft 8. According to whether the displacement element 21.2 is on the right or the left of the shaft 8, this pitch can be altered positively or negatively. Here, too, the rocking lever 20.2, the sliding swivel joint 22.2 composed of the sliding-block member 23.2 and the pivot bearing 25.0, and the displacement element 21.2 form a sliding coupling wherein the sliding swivel joint 22.2 can be displaced continuously along the rocking lever 20.2 and be locked by the locking device 28. The devices shown in FIGS. 1 to 3 can be combined with one another. According to FIGS. 1 and 2, the displacement element 21.1 performs horizontal linear movements, whereas the displacement element 21.2 shown in FIG. 3 performs vertical linear movements. It is possible, for example by means of a wedge surface, to convert the horizontal movements of the displacement element 21.1 into linear vertical movements in order to be able to move the slide plate 30 upwards and downwards thereby. In a corresponding manner, it is possible to convert the vertical movements of the displacement element 21.2 into horizontal movements by means of this wedge surface in order to reciprocate the worm shaft 17 thereby. With regard to the form of embodiment according to FIG. 3, it should also be noted that the length of the connecting rod 5 is variable and the horizontal shaft 8 can be adjusted in height by varying the length of the bearing member 9.1 at the frame side. Whereas in the form of the embodiments of FIGS. 1 through 3 previously described, the rocking lever 20 performs movements of a rocker arm of the reciprocating drive about the axis of the shaft 8, in the following embodiments, the axial movements of the tool spindle 1 are taken off from the rocking lever or transmitted to this. Thus, in the forms of embodiment according to FIGS. 1 to 3, the turning and sliding joint 22 has converted a rotary movement of the rocking lever 20 into a linear movement of the displacement element 21 in each case. In the following embodiments, a further turning and sliding joint is provided which converts the linear axial movements of the tool spindle 1 into reciprocating circular movements of one or two rocking levers and then the turning and sliding joint previously described converts these reciprocating circular movements into reciprocating linear movements for the drive of the indexing mechanism. According to FIGS. 4 and 5, the tool spindle 1 comprises a ring 32 which is rigidly connected thereto and which is illustrated in FIG. 7. This ring is surrounded by a collar member 33 which comprises an arm 34 extending downwards. The collar member 33 and the arm 34 are thus moved linearly upwards and downwards by the tool spindle 1. At the lower end of the arm 34, there is provided a sliding swivel 35 which consists of a sliding-block member 35.1 and a pivot bearing 35.2, and the latter connects the arm 34 to the sliding-block member 35.1. The sliding block member 35.1 is in engagement with the rocking lever 20.3 which is mounted for rotation fixed to the frame by the shaft 8. The rocking lever 20.3 extends substantially at right angles to the tool spindle 1. Disposed between the displacement plate 30 constructed in the form of a displacement element 21.3 and the rocking lever 20.3 is the sliding swivel joint 22.3 which consists of a first sliding-block member 23.3 and a second sliding-block member 24.3 which are connected to one another through a pivot bearing. The pivot bearings of the two sliding swivel joints 35 and 22.3 each have axes of rotation extending parallel to the axis of the shaft 8. The sliding-block member 24.3 can be locked on the displacement member 21.3 which extends substantially parallel to the rocking lever 20.3. The sliding swivel joint 22.3 is displaceable continuously along the displacement element 21.3 and along the rocking lever 20.3 and can be locked to the displacement element 21.3 in each position of displacement. According to the position of the sliding swivel joint 22.3 to the right or left of the shaft 8, the pitch of the helical movement is altered positively or negatively. A further possibility for variation can be achieved if the other sliding swivel joint 35 is also adapted for displacement along the rocking lever 20.3. In FIGS. 4 to 7, the workpiece to be machined by the tool 2 is illustrated and designated by 36. A possibility for continuous adjustment of the sliding swivel joint 22.3 is illustrated in FIG. 5. Fixed to the displacement plate 30 is a bearing block 37 through which there extends an adjusting spindle 26 which is in engagement with the sliding-block member 24.3 with which the sliding swivel joint 22.3 can be displaced along the displacement element 21.3 and hence along the rocking lever 20.3. If the adjusting spindle 26 is supported appropriately stably in the bearing block 37 and in the sliding-block member 24.3, a locking device can be omitted on the sliding-block member 24.3. In the form of the embodiment shown in FIGS. 6 and 7, two rocking levers 20.4 and 37 are provided. The rocking levers extending parallel to one another are mounted for rotation on the side of the frame by the shafts 8 and 38. At least at one end, they are connected to one another by an articulated lever 39 through a pivot joint. An additional connection through a further articulated lever may be provided at the other end of the rocking levers. The collar member 33 is connected to the rocking lever 37 through a sliding swivel joint 35. It comprises a sliding-block member 35.1 and a pivot bearing 35.2. The sliding-block member is guided in a longitudinal guide 35.3 of the rocking lever 37 and connected to the collar member 33 through the pivot bearing 35.2. The lower rocking lever 20.4 is kinematically connected to the displacement element 21.4 of the displacement plate 30 through the sliding swivel joint 22.4 which is displaceable and locatable along the rocking lever 20.4 and the displacement element 21.4. This displaceable sliding swivel joint 22.4 comprises a sliding-block member 23.4 and a further sliding-block member 24.4 which can be connected to one another through the swivel joint 25.0. The sliding-block member 24.4 is made U-shaped and can be locked on the displacement element 21.4. The other sliding-block member 23.4 is guided in a longitudinal guide 40 which extends at both sides of the shaft 8. Here, too, there is an additional possibility of adjustment for the pitch of the helical movement if the sliding swivel joint 35 is adapted for displacement and location along the rocking lever 37 and the collar member 33. Some further advantages: With linear dependence of the pitch of the helix to be achieved on the extent of the adjustment, this pitch can be adjusted by simpler means than with non-linear dependence. The spacing to be adjusted is on a member which is moved only by sliding. It always lies in a horizontal line. The means for adjusting it can be simpler than those which are necessary to adjust a spacing on a rotating member. The adjustment can be effected and measured by simple means even when the rocker is inclined. In the modifications given, a direct adjustment of the quantity determining the helix angle (vertical distance of the axis of rotation of the journal bearing between the sliding-block members 23.1 and 24.1 and the axis of rotation of the ram spindle) is possible. A simpler construction of such a device is possible as a result of the invention and lower costs are incurred. In the mechanism according to the present invention, fewer bearing locations are needed so that fewer components are necessary and therefore a greater manufacturing accuracy is achieved in the workpieces produced. As a result of the smaller number of moving parts, less vibration occurs in the system and therefore lower power losses. It is to be understood that the invention is not limited to the illustrations described and shown herein, which are deemed to be merely illustrative of the best modes of carrying out the invention, and which are susceptible of modification of form, size, arrangement of parts and details of operation. The invention rather is intended to encompass all such modifications which are within its spirit and scope as defined by the claims.

4y

FIELD The present teachings generally relate to a tool for machining workpiece surfaces. BACKGROUND Tools of the type mentioned here are known. They have at least one adjustable, geometrically defined cutting edge, in addition to an adjusting device, with which the distance of the cutting edge from the central axis of the workpiece can be adjusted. The adjusting device comprises a drive that acts on the adjusting slide via a gearbox, which determines the distance of the cutting edge from the central axis of the workpiece. The adjusting slide is arranged eccentrically to the central axis of the workpiece and designed as a round slide, i.e., the adjusting slide is rotated for the adjustment of the distance of the cutting edge to the central axis of the workpiece, so that a cutting edge that is attached to an adjusting slide is displaced in such a way that the distance to the central axis of the workpiece is changed. The disadvantage of this tool is that the adjustment of the cutting edge cannot take place with specifically high precision, because the adjusting slide is changed by means of a spur gear in its position. Defects in the gear teeth, such as the spacing between the gear teeth or play between the interactive spur gears directly interfere with the positioning of the cutting edge. The latter may also not be precisely adjusted due to the defect. The task of the invention is thus to develop a tool for machining workpiece surfaces of the type mentioned here, in which this disadvantage does not exist in this fashion. SUMMARY In order to solve this task, a tool is proposed that has an adjustable, geometrically defined cutting edge, which is adjustable by means of an adjusting device. In this manner, the distance of the cutting edge to the central axis of the tool may be predetermined. The adjusting device has a drive, which acts on a gearbox via at least one spur gear. This directly affects the position of the adjusting slide, thus the distance of the geometrically defined cutting edge to the central axis of the workpiece. Thus, a spur gear is no longer envisioned between the gearbox and the adjusting slide, contrary to the known solution, so that here also, no spacing and/or play defect can occur. Due to the fact that the gearbox has a high gear reduction, defects during the transfer of a torque from the drive via spur gears to the gearbox corresponding to the gear reduction of the gearbox are reduced. In this manner, it is possible, despite gear tooth defects that can never be completely avoided, to guarantee a very precise positioning of the cutting edge. BRIEF DESCRIPTION OF THE DRAWINGS The invention is further explained below by means of the drawing. Shown are: FIG. 1A schematic diagram of a lateral view of the tool FIG. 2 Another simplified schematic diagram of a lateral view of a tool, whereby the tool is rotated 90° with respect to FIG. 1 , and FIG. 3 A schematic diagram of a front view of a tool with various positions of a cutting edge. DETAILED DESCRIPTION The schematic diagram according to FIG. 1 shows a tool 1 that may be connected via a shaft 3 , which is only indicated here, to a spindle of a tool machine or with interfaces, adapters or the like. On the side 5 opposite the shaft 3 , a geometrically defined cutting edge 7 is indicated. This may be part of the tool or a cutting tip plate that is fastened to tool 1 in a suitable manner. It is possible to also envision a suitable tool holder, such as a magazine or the like. The main body 9 of tool 1 comprises, for example, a drive 11 designed as an electric motor, which can be controlled via a suitable control system 13 , whereby drive 11 can be switched on and off as and the speed and the rotating direction of the driven shaft 15 of drive 11 can be predetermined. An initial spur gear 17 is attached torque proof to the free end of the driven shaft 15 . The rotation of the initial spur gear 17 is transmitted in a suitable manner to a second spur gear 19 . A transmitting device 21 lies outside the image plane according to FIG. 1 , which will be explained in greater detail below. The second spur gear is attached torque proof to the end of a drive shaft 23 , which transmits a rotation and a torque of the second spur gear 19 to a gearbox 25 . This is characterized preferably by a high speed reduction. Here planetary gears or, in particular, also a harmonic drive gearbox can be used. With gearbox 25 illustrated here, it is envisioned that a rotary motion introduced via the drive shaft 23 in gearbox 25 is transmitted to housing cap 27 of gearbox 25 . It appears in the process that this rotates with a much smaller rotational speed than drive shaft 23 . If the second spur gear 19 of drive 11 rotates at a given rotating angle, housing cap 27 rotates only at a very much smaller rotating angle corresponding to the gear reduction of gearbox 25 . Drive 11 and gearbox 25 are components of an adjusting device 29 , which furthermore still comprises an adjusting slide 31 . It can be seen from the schematic diagram that gearbox 25 acts directly on the adjusting slide 31 . Here it is envisioned that the adjusting slide is directly connected to the drive, which is designated here as housing cap 27 . A rotation of housing cap 27 thus directly produces a rotation of the adjusting slide 31 designed as a rotating round slide, whereby a rotation of housing cap 27 1:1 is transmitted to adjusting slide 31 . It is clear that a rotation produced by drive 11 is transmitted to gearbox 25 of spur gear 17 via transmitting device 21 and via the second spur gear 19 . The latter is connected torque proof to drive shaft 23 , which introduces a rotary motion of the second spur gear 19 in gearbox 25 . Tolerances have an effect on the path between drive 11 and drive shaft 23 during the manufacturing on both the drive itself and spur gears 17 and 19 as well as transmitting device 21 . These defects are strongly reduced by gearbox 25 . A given rotating angle at the entry of gearbox 25 , thus on drive shaft 23 , produces a much smaller rotating angle corresponding to the gear reduction of the gearbox at its exit, i.e., housing cap 27 . Rotating angle defects that occurred in the area between drive 11 and drive shaft 23 are likewise reduced corresponding to the gear reduction of gearbox 25 and thus produce a very much smaller rotating angle defect at the exit side of the gearbox, i.e., housing cap 27 . It is critical that that no more spur gears be interconnected between housing cap 27 and adjusting slide 31 , whose manufacturing tolerances could distort the rotating angle of housing cap 27 . In fact, a given rotating angle of housing cap 27 leads directly to a rotation of the adjusting slide 31 designed as a round slide. The resulting gear reduction in gearbox 25 of a rotating angle defect in the area of the drive shaft 23 is thus maintained unaltered during the rotating displacement of adjusting slide 31 . The distance of cutting edge 7 to central axis 33 of tool 1 is adjusted by means of the adjusting device 29 . In order to produce a change of this distance by a rotation of adjusting slide 31 , its rotating axis 35 is shifted parallel to central axis 33 ; adjusting slide 31 is thus arranged eccentrically in the main body 9 of tool 1 . At the same time, the second spur gear 19 is also arranged coaxially to rotating axis 35 and thus eccentrically to the central axis of tool 1 . With the embodiment selected here, gearbox 25 thus also lies eccentrically to central axis 33 and coaxially to rotating axis 35 . FIG. 2 shows a schematic diagram of the components of the tool 1 illustrated in FIG. 1 , i.e., drive 11 , its driven shaft 15 as well as the first spur gear 17 . Transmitting device 21 is clearly visible here, because the components of tool 1 are clearly rotated 90° with respect to the illustration in FIG. 1 . Transmitting device 21 has an initial first pinion gear 37 that meshes with the first spur gear 17 , which acts on a second pinion gear 41 via a transfer shaft 39 . This meshes with the second spur gear 19 . Depending upon the arrangement of transmitting device 21 , thus after the selection of the diameter of the first spur gear 17 , of the first pinion gear 37 , of the second pinion gear 41 and of the second spur gear 19 , a desired gearbox ratio may be predetermined. It is clear here that a rotation of driven shaft 15 of drive 11 by means of the transmitting device 21 leads to a rotation of drive shaft 23 , which is introduced in gearbox 25 . Here, this is also configured as high-reduction gearing. A rotation of the drive shaft 23 also leads to a rotation of the housing cap 27 , whereby the rotating direction of housing cap 27 is opposite to that of drive shaft 23 , if the gearbox 25 is configured as a harmonic drive gearbox or planetary gears. After reading the explanations, it is evident that a rotation of driven shaft 15 leads to a rotation of housing cap 27 . At the same time, a rotation of the first spur gear 17 by means of the transmitting device 21 is transmitted to the second spur gear 19 . The rotating angle of the first spur gear 17 is very greatly reduced by gearbox 25 , so that a very much smaller rotating angle is produced for housing cap 27 . The speed reduction of the gearbox also leads to the defect in the gear tooth system between the first spur gear 17 and the second pinion gear 37 as well as between the second pinion gear 41 and the second spur gear 19 are correspondingly “reduced”, or diminished. In other words: Defects in the gear teeth between spur gear 17 and 19 and in transmitting device 21 are substantially reduced by gearbox 25 and, for all intents and purposes, no longer affect the adjustment of cutting tip plate 7 connected via an adjusting slide 31 to housing cap 27 . Transmitting device 21 illustrated in FIG. 2 may also be modified: FIG. 2 illustrates that the first and second spur gears 17 and 19 mesh with the first and second pinion gears 37 and 41 . It is also conceivable that, instead of the spur gears and pinion gears, pulleys are used and a rotation of the first spur gear 17 is transmitted to the first pinion gear 37 by means of a belt. At the same time, for the second spur gear 19 on the other hand, a spur gear may again be used or, likewise, a belt pulley. This also applies to the second pinion gear 41 . Also, it must still be indicated, that spur gears 17 and 19 are here only approximately commensurately designed as an example. Spur gears with different diameters may also be used here. In addition, it is possible to design the first and/or second spur gear 17 , 19 as a hollow gear with internal teeth and correspondingly, the first and/or second pinion gear, 37 , 41 can be meshed within this hollow gear. Another modification of the transmitting device 21 may designed, in which the first spur gear 17 is designed substantially smaller and meshes with a second spur gear 19 designed as an hollow gear whose diameter is greater than that of the first spur gear 17 . The eccentric misalignment may thus also be realized by means of a single-stage gearbox with internal teeth. Finally, it should still be indicated that transmitting device 21 may also be realized by a multi-stage gearbox. FIG. 3 shows a schematic diagram of tool 1 from the front, thus on side 5 , lying opposite the shaft 3 . The illustration shows a cutting edge 7 , which is a component of a cutting tip plate 43 , in various positions. According to the rotating position of the adjusting slide 31 , cutting edge 7 is arranged at a more or less great distance to the central axis 33 of tool 1 . Below to the right, beneath a horizontal diameter line D 1 , cutting edge 7 is arranged here at a distance to rotating axis 33 . With a corresponding layout of tool 1 , this may, for example, be selected in such a way that a borehole machined with a cutting edge 7 has a diameter of approx. 38.0. If adjusting slide 31 is designed as a rotating slide valve rotates in the direction of arrow 45 , thus counterclockwise, so that, with a corresponding layout of working spindle 1 , cutting edge 7 is at a distance from central axis of tool 1 , with the machining of a borehole by means of tool 1 , a diameter of approx. 41.5 mm is produced. If adjusting slide 31 further rotates counterclockwise in the direction of arrow 45 , so that it lies just in front of the perpendicular diameter line D 2 , a diameter of approx. 48.0 mm is produced when the borehole is machined by means of tool 1 . If, finally, adjusting slide 31 is rotated in such a way that cutting edge 7 is lined up with the graduation of D 2 , then a diameter of 48.23 mm is produced when the borehole is machined by means of tool 1 . It is clear here, that the adjustment of the diameter of tool 1 depends upon a rotation of adjusting slide 31 . Rotating angle defects thus lead to a deviation of the set diameter of tool 1 from the target diameter. As explained above, rotating angle defects between drive 11 and the entrance of gearbox 25 , thus at its drive shaft 23 , are strongly reduced by gearbox 25 . In other words, the reduction of gearbox 25 reduces an existing rotating angle defect at the entrance of the gearbox in such a way that it practically no longer has any effect at the exit of the gearbox and thus on housing cap 27 . Thus, the rotating angle appears to correspond exactly to the rotating angle of rotating slide valve 31 of housing cap 27 . As a result, the advantage of using this tool 1 described herein is obtainable, because gearbox 25 has a high reduction and directly acts on adjusting slide 31 , thus without any interconnections of further spur gears or the like. The difference between the smallest and the largest indicated borehole diameter depends upon how great the distance between central axis 33 of tool 1 and rotating angle 35 of adjusting slide 31 is. The greater the distance “e” is, so much greater the difference of both indicated diameters is. The change of the diameter of a borehole by means of tool 1 is exclusively produced by a rotary motion of the adjusting slide 31 . The result is that a sealing of the tool in an easy manner is possible. It requires only the use of rotating seals. Losses can be reduced to a minimum by means of antifriction bearings, so that no slide bearings are used. With the rotation of adjusting slide 31 , a once balanced tool 1 remains balanced: With diameter adjustment, no centers of mass/gravity actually move, so very high machining speeds are possible. Moreover, the balancing of the tool is likewise relatively easy. From the explanations, it appears that all of the backlashes occurring up to gearbox 25 are reduced with the reduction factor of gearbox 25 . The disengaging of drive 11 , thus the angle adjustment of the first spur gear 17 , is increased by the reduction. In addition, it appears that with a higher reduction of gearbox 25 , also with small motors, that are used as drive 11 , high torque can be produced during the displacement of adjusting slide 31 . To increase the precision of the tool, so-called pre-stressed and thus spur gears free of play can be used. By means of a suitable control of drive 11 by means of the control system 13 , the distance of cutting edge 7 from the central axis 33 of the tool can be changed during the machining of a borehole surface. It is thus possible to produce boreholes with a contour, such as chamfering, annular grooves, undercuts, conical boreholes and the like.

4y

CROSS-REFERENCES TO RELATED APPLICATIONS This application is a continuation application of parent application Ser. No. 09/051,210, filed Jul. 13, 1998 which was derived from PCT International application no. PCT/GB96/02434, filed Oct. 4, 1996. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a liquefaction apparatus, and more particularly relates to an offshore apparatus for liquefying natural gas. 2. Description of the Related Art Natural gas is obtained from gas, gas/condensate and oil fields occurring in nature, and generally comprises a mixture of compounds, the most predominant of which is methane. Usually, natural gas contains at least 95% methane and other low boiling hydrocarbon (although it may contain less); the remainder of the composition comprises mainly nitrogen and carbon dioxide. The precise composition varies widely, and may include a variety of other impurities including hydrogen sulphide and mercury. Natural gas may be “lean” gas or “rich” gas. These terms do not have a precise meaning, but it is generally understood in the art that a lean gas will tend to have less higher hydrocarbons than a rich gas. Thus, a lean gas may contain little or no propane, butane or pentane, whereas a rich gas would contain at least one of these materials. Since natural gas is a mixture of gases, it liquifies over a range of temperatures; when liquefied, natural gas is called “LNG” (liquefied natural gas). Typically, natural gas compositions will liquefy, at atmospheric pressure, in the temperature range −165° C. to −155° C. The critical temperature of natural gas is about −90° C. to −80° C., which means that in practice it cannot be liquefied purely by the application of pressure it must be also be cooled below the critical temperature. Natural gas is often liquefied before being transported to its point of end use. Liquefaction enables the volume of natural gas to be reduced by a factor of about 600. The capital costs, and running costs, of the apparatus required to liquefy the natural gas is very high, but not as high as the cost of transporting unliquefied natural gas. The liquefaction of natural gas can be carried out by cooling the gas in countercurrent heat exchange relationship with a gaseous refrigerant, rather than with the liquid refrigerants used in conventional liquefaction methods, such as the cascade or propane-precooled mixed refrigerant processes. At least part of the refrigerant is passed through a refrigeration cycle which involves at least one compression step and at least one expansion step. Before the compression step, the refrigerant is usually at ambient temperature (ie the temperature of the surrounding atmosphere). During the compression step, the refrigerant is compressed to a high pressure, and is warmed by the compression process. The compressed refrigerant is then cooled with the ambient air, or with water if there is a water supply available, to return the refrigerant back to ambient temperature. The refrigerant is then expanded in order to cool it further. There are basically two methods of achieving the expansion. One method involves a throttling process, which may take place through a J-T valve (Joule-Thomson valve), wherein the refrigerant is expanded substantially isenthalpically. The other method involves a substantially isentropic expansion, which may take place through a nozzle, or, more usually, through an expander or turbine. The substantially isentropic expansion of the refrigerant is known in the art as “work expansion”. When the refrigerant is expanded through a turbine, work may be recovered from the turbine: this work can be used to contribute to the energy required to compress the refrigerant. It is generally recognised that work expansion is more efficient than throttling (a greater temperature drop can be achieved for the same pressure reduction), but the equipment is more expensive. As a result most processes usually use only work expansion, or a mixture of work expansion and throttling. When natural gas of a particular composition is cooled at a constant pressure, then for any given temperature of the gas there will be a particular value for the rate of change of enthalpy (Q) of the gas. The temperature (T) can be plotted against Q to produce a “cooling curve” for natural gas. The cooling curve is highly dependent upon pressure: if the pressure is below the critical pressure, then the T/Q cooling curve is highly irregular, ie, it contains several portions of different gradient, including a portion of zero, or close to zero, gradient. With increases in pressure, particularly above the critical pressure, the T/Q cooling curve tends towards a straight line. Reference is now made to FIG. 1, which is a graph of temperature vs. rate of change of enthalpy for the cooling of natural gas below and above critical pressure. The curve A, which is for the cooling of natural gas below critical pressure, will be considered in more detail. The curve A has a characteristic shape, which can be divided into a number of regions. Region 1 has a constant gradient and represents the sensible cooling of the gas. Region 2 has a decreasing gradient and is below the dew point temperature of the gas as heavier components begin to condense. Region 3 corresponds to the bulk liquefaction of the gas and has the lowest gradient in the curve: the curve in this portion is almost horizontal. Region 4 has an increasing gradient and is above the bubble point temperature of the liquid as the lightest components are condensed. Region 5 is below the bubble point temperature and is of a constant gradient, which is greater than the gradient of regions 3 and 4 . Region 5 corresponds to the sensible cooling of the liquid; this is known as the “sub-cooling” region. Reference is now made to FIG. 2 of the drawings, which is a graph of T/Q showing the combined cooling curve for natural gas and nitrogen, for a natural gas pressure of about 5.5 MPa. The graph also shows the warming curve for nitrogen over the same temperature range. This graph is representative of a liquefaction system in which natural gas is cooled in a series of heat exchangers by a simple nitrogen expander cycle. The nitrogen refrigerant exiting the series of heat exchangers is compressed, cooled with ambient air, cooled to about −152° C. by work expansion, then fed to the cold end of the series of heat exchangers. The nitrogen refrigerant is precooled, before work expansion, by being passed through at least one heat exchanger at the warm end of the series of heat exchangers; thus, the cooling curve is a combined natural gas/nitrogen cooling curve. The gradient of the cooling and warming curves at any particular point in FIG. 2 is dT/dQ. It is well known in the liquefaction field that the most efficient process is one which, for any given value of Q, the corresponding temperature on the cooling curve of the natural gas is as close as possible to the corresponding temperature on the warming curve of the refrigerant. This has the implication that dT/dQ for the cooling curve of the natural gas is as close as possible to dT/dQ for the warming curve of the refrigerant. However, for any given Q, the closer the temperature of the natural gas and the refrigerant, the higher the surface area needed for the heat exchanger. Thus, there has to be a certain trade off between minimising the temperature difference, and minimising the heat exchanger surface area. For this reason, it is generally preferred that for any given Q, the temperature of the natural gas is at least 2° C. higher than that of the refrigerant. In FIG. 2, the nitrogen warming curve is approximately a single straight line (ie, it has constant gradient). This is representative of a single stage refrigeration cycle, wherein the all the refrigerant nitrogen is cooled by work expansion to a low temperature of about −160° C. to −140° C., and is then passed in countercurrent heat exchange relationship with the natural gas. It is clear that at most parts of the T/Q curve there is a large temperature difference between the natural gas and the nitrogen refrigerant, and this indicates that the heat exchange is highly inefficient. It is also known that the gradient of the warming curve of the refrigerant can be altered by changing the flow rate of the refrigerant through the heat exchangers: specifically, the gradient can be increased by decreasing the refrigerant flow rate. In the system shown in FIG. 2 it is not possible to decrease the nitrogen flow rate, because the increase in gradient will cause the nitrogen warming curve to intersect with the natural gas cooling curve. An intersection of the two curves is indicative of a temperature “pinch” or “cross-over” in the heat exchanger between the nitrogen and the natural gas, and under this condition it is impossible for the process to work. However, if the nitrogen flow is split into two streams it is possible to make the nitrogen warming curve change from a single straight line into two intersecting straight line portions of different gradient. An example of such a process is disclosed in U.S. Pat. No. 3,677,019. This specification discloses a process in which the compressed refrigerant is split into at least two portions, and each portion is cooled by work expansion. Each work expanded portion is fed to a separate heat exchanger for cooling the gas to be liquefied. This causes the refrigerant warming curve to comprise at least two straight line portions of different gradient. This aids in the matching of the warming and cooling curves and improves the efficiency of the process. This specification was published over twenty years ago, and the process disclosed therein is inefficient by modern standards. In U.S. Pat. No. 4,638,639 there is disclosed a process for liquefying a permanent gas stream, which also involves splitting the refrigerant stream into at least two portions in order to match the cooling curve of the gas to be liquefied with the warming curve of the refrigerant. The outlet of all the expanders in this process is at a pressure above about 1 MPa. The specification suggests that such high pressures increase the specific heat of the refrigerant, thereby improving the efficiency of the refrigerant cycle. In order to realise an efficiency improvement it is necessary for the refrigerant to be at, or near, its saturation point at the outlet of one of the expanders, because the specific heat is higher near to saturation. If the refrigerant is at the saturation point, then under these conditions there will be some liquid in the refrigerant that is fed to the heat exchangers. This leads to additional expense, because either the heat exchanger needs to be modified in order to handle a two-phase refrigerant, or the refrigerant needs to be separated into liquid and gaseous phases before being fed to the heat exchanger. U.S. Pat. No. 4,638,639 is primarily concerned with processes in which the refrigerant comprises a portion of the gas to be liquefied, ie the refrigerant is the same as the gas to be liquefied. The specification is particularly concerned with a system in which nitrogen is liquefied using a nitrogen refrigerant. The specification does not specifically disclose a process in which natural gas is cooled by nitrogen, nor would it be expected to be useful in such a process, because all modern large-scale processes for liquefying natural gas use a mixed refrigerant cooling cycle. Furthermore, in U.S. Pat. No. 4,638,639 the gas being liquefied is cooled to a temperature just below its critical temperature. A series of three J-T valves are provided to sub-cool the gas being liquefied. The earliest refrigerant cycle used for the liquefaction of natural gas was the cascade process. Natural gas can be cooled in the cascade process by successive cooling with, for example, propane, ethylene and methane refrigerants. The mixed refrigerant cycle, which was developed later, involves the circulation of a multi component refrigerant stream, usually after precooling to −30° C. with propane. The nature of the mixed refrigerant cycle is such that the heat exchangers in the process must routinely handle the flow of a two phase refrigerant. This requires the use of large, specialised heat exchangers. The mixed refrigerant cycle is the most thermodynamically efficient of the previously known natural gas liquefaction processes: it enables the warming curve of the refrigerant to be closely matched to the cooling curve of the natural gas over a wide temperature range. Examples of mixed refrigerant processes are disclosed in U.S. Pat. Nos. 3,763,658 and 4,586,942, and in European Paten No 87,086. One of the reasons for the widespread use of the mixed refrigerant cycle in the cooling of natural gas is the efficiency of that process. The installation of a typical mixed refrigerant liquefaction plant for natural gas would cost upward of $US 1,000,000,000, but the high cost can be justified by the efficiency gains. In order to be cost effective through economy of scale the mixed refrigerant plants typically need to be able to produce at least 3 million tonnes of LNG per annum. The size and complexity of mixed refrigerants liquefaction plants is such that, to date, they have all been constructed, and located, on land. Due to the size of natural gas liquefaction plants, and the requirement for deep water harbours, they cannot always be located near to the natural gas fields. Gas from the natural gas fields is usually transported to the liquefaction plant by pipeline. In the case of offshore natural gas fields, there are severe practical limitations on the maximum length of the pipeline. This means that offshore natural gas fields that are more than about 200 miles from land are seldom developed. BRIEF SUMMARY OF THE INVENTION According to one aspect of the present invention there is provided an offshore apparatus for liquefying natural gas, comprising a support structure which is either floatable or is otherwise adapted to be disposed in an offshore location at least partially above sea level, and natural gas liquefaction means disposed on or in the support structure, the natural gas liquefaction means comprising a series of heat exchangers for cooling the natural gas in countercurrent heat exchange relationship with a refrigerant, compression means for compressing the refrigerant, and expansion means for isentropically expanding at least two separate streams of the compressed refrigerant, wherein said expanded streams of refrigerant communicate with a cool end of a respective one of the heat exchangers. The support structure may be a fixed structure, ie a structure that is fixed to the seabed, and is supported by the seabed. Preferred forms of fixed structure include a steel jacket support structure and a gravity base support structure. Alternatively, the support structure may be a floating structure, ie a structure that floats above the seabed. In this embodiment, the support structure is preferable a flatable vessel having a steel or concrete hull, such as a ship or a barge. In one preferred embodiment, the support structure is a floating production storage and off-loading unit (FPSO). Pretreatment means is usually provided for pretreating the natural gas before it is delivered to the liquefaction means. The pretreatment means may include separation stages for removing impurities, such as condensate, carbon dioxide and produced water. The natural gas liquefaction apparatus may be provided in combination with storage means for receiving and storing the natural gas after it has been liquefied. The storage means may be provided on or in the support structure. Alternatively, the storage means may be provided on a separate support structure, which is either floatable or otherwise adapted to be disposed in an offshore location at least partially above sea level; the separate support structure may be of the same type as, or of a different type to, the support structure for the liquefaction means. It is particularly preferred that the support structure is a ship, and that the liquefaction means and the storage means are provided on said ship. In a preferred embodiment, the support structure comprises two spaced gravity bases, and a platform bridging said gravity bases, wherein said storage means comprises a storage tank provided on or in at least one of said gravity bases, and wherein the liquefaction means is provided on or in said bridging platform. Means can be provided for connecting said apparatus to a subsea well, whereby the natural gas can be delivered to the liquefaction means at a pressure above 5.5 MPa, said pressure being derived directly or indirectly from the pressure in the subsea well. To facilitate this, the apparatus according to the invention can be located sufficiently close to the natural gas producing formation that the pressure of the natural gas in the series of heat exchangers can be provided substantially entirely by the pressure inherent in the natural gas producing formation. In certain gas fields, some of the gas may be recompressed for re-injection, and therefore may be available at a high pressure if passed through one or more compression stages of the re-injection apparatus before being passed to the liquefaction means. According to another aspect of the invention there is provided natural gas liquefaction apparatus, for offshore installation, comprising: natural gas liquefaction means having (i) a series of heat exchangers for cooling the natural gas in countercurrent heat exchange relationship with a refrigerant, (ii) compression means for compressing the refrigerant, and (iii) expansion means for isentropically expanding at least two separate streams of the compressed refrigerant, wherein said expanded streams of refrigerant communicate with a cool end of a respective one of the heat exchangers; and a support frame carrying the components of the liquefaction means as a single unit for transportation to, and installation at, the offshore location. Preferably, the liquefaction means further comprises cooling means for cooling the refrigerant after it has been compressed and before it is isentropically expanded, said cooling means comprising a heat exchanger, a liquid coolant and a refrigeration unit for cooling the coolant to a temperature between −10° C. and 20° C., wherein the compressed refrigerant is cooled in said heat exchanger in countercurrent relationship with said coolant. The expansion means may comprise a work expander disposed in each of said compressed refrigerant streams, and the compression means may comprise at least one compressor. The compression means preferably comprises a first compressor adapted to compress the refrigerant to an intermediate pressure, and a second compressor adapted to compress the refrigerant to a higher pressure. The second compressor is desirably operatively connected to the refrigerant expander means, whereby substantially all the work required to compress the refrigerant from the intermediate pressure to the higher pressure is provided by the expansion means. In one construction the expansion means comprises two turbo expanders, and the second compressor comprises two compressors each operatively connected to a respective one of the turbo expanders. In another construction the refrigerant expander means comprises two turbo expanders, and the second compressor comprises a single compressor operatively connected to both the turbo expanders by means of a common shaft. An aftercooler is generally provided for cooling the compressed refrigerant from the second compression means. The first compressor may comprise a single compressor with an aftercooler for cooling the compressed refrigerant, but it is preferred that the first compressor comprises a series of at least two compressors with an intercooler between each compressor of the series, and an aftercooler after the last compressor of the series. The series of heat exchangers preferably comprises an initial heat exchanger, an intermediate heat exchanger and a final heat exchanger, and the natural gas is passed sequentially through the initial, the intermediate and the final heat exchangers in order to cool it to successively cooler temperatures; refrigerant in a first of said refrigerant streams is delivered to the final heat exchanger, and refrigerant in a second of said refrigerant streams is delivered to the intermediate heat exchanger. The refrigerant may be cooled in the initial heat exchanger after being compressed, but before being isentropically expanded, and the refrigerant in said first refrigerant stream may be cooled in the intermediate heat exchanger after being cooled in the initial heat exchanger, but before being isentropically expanded. The apparatus is preferably operated such that the final heat exchanger receives refrigerant from the first refrigerant stream, and the relative flowrates of the first and second refrigerant streams are such that the warming curve for the refrigerant comprises a plurality of segments of different gradient, the refrigerant is warmed in said final heat exchanger to a temperature below −80° C., and the coolest refrigerant temperature and the flowrate of refrigerant in said first refrigerant stream are such that a part of the refrigerant warming curve relating to the final heat exchanger is at all times within 1 to 10° C., preferably 1 to 5° C., of the corresponding part of the cooling curve for the natural gas. It will usually be most efficient to operate the heat exchangers such that the temperature difference between the natural gas cooling curve and the corresponding part of the refrigerant warming curve is between 1° C. and 5° C. Typically this temperature difference will be above 2° C., because smaller temperature differences require larger, more expensive, heat exchangers, and there is a greater risk that a temperature pinch will be inadvertently created in the heat exchanger. However, in circumstances where there is a surplus of energy available, it can be sensible to operate with temperature differences above 5° C., and perhaps as high as 10° C.: this enables the size of the heat exchangers to be reduced, thereby saving capital costs. The apparatus is preferably operated such that the coolest refrigerant temperature is no greater than −130° C., whereby the natural gas is sub-cooled substantially in said series of heat exchangers. Most preferably, the coolest refrigerant temperature is in the range −140° C. to −160° C. The liquefaction means may further comprise a gas turbine for generating power for the compression means. The gas turbine preferably comprises an aero-derivative gas turbine; this is advantageous because it has a smaller size and weight than the alternative industrial type gas turbines commonly used in onshore LNG plants. In addition, the aero-derivative turbine has high thermal efficiency, and it is easy to maintain due to its light weight components. The number and rating of the turbines depends upon the amount of LNG that it is desired to produce; for example, to produce about 2 million tonnes LNG/annum would require two aero-derivative turbines each rated at about 40 MW. It is preferred that the liquefaction means further comprises a second series (or “train”) of heat exchangers, said second series of heat exchangers being arranged in parallel with said first series of heat exchangers, and a separate refrigerant compression means and refrigerant expansion means for each series of heat exchangers. At least some of the or each series of heat exchangers and pipework connected thereto are preferably disposed within a single, common heat insulating housing—this is known as a “cold box”, and it usually contains pearlite or rock wool. When there is more than one heat exchanger train, it is preferred that each heat exchanger train is disposed in its own cold box. The liquefaction means may further comprise natural gas expansion means adapted to receive and expand sub-cooled natural gas from the series of the heat exchangers; the expansion means serves to expand the sub-cooled natural gas to a sub-critical pressure, thereby simultaneously cooling and liquefying the natural gas. The expansion means may be substantially isenthalpic expansion means, such as a J-T valve, or substantially isentropic expansion means, such as a liquid or hydraulic turbine expander. When the expansion means comprises a liquid or hydraulic turbine expander, or other work-producing expansion means, it is preferred that an electrical generator is provided. The generator is arranged to convert the work produced by the expansion means into electrical energy. The liquefaction means may further comprise a flash vessel adapted to receive expanded natural gas from the natural gas expansion means. In practice the expanded natural gas comprises a two phase mixture of liquid and gas. The flash vessel is provided with a fuel gas exit, through which natural gas comprising mainly methane and a lesser amount of nitrogen is taken, and a LNG exit through which LNG is taken. It is preferable that the flash vessel is provided in the form of a fractionating column having a reboiler which comprises a heat exchanger arranged to warm a liquid stream, taken from the column, in countercurrent heat exchange relationship with natural gas exiting said series of heat exchangers. A fuel gas compressor means can be provided to compress the fuel gas to a suitable pressure for use in a gas turbine, after the gas is warmed in a heat exchanger. The flash vessel is preferably disposed within the cold box. It is desirable that the gas turbine is powered by fuel gas derived from the fuel gas exit of the flash vessel: by means of this arrangement, all the work required to compress the refrigerant is provided to the first compressor means, and this work is entirely provided by fuel gas created by the liquefaction process. There are a number of suitable embodiments for the heat exchangers in the series. Aluminum plate-fin heat exchangers can only be manufactured up to a certain size and a number of individual cores must be manifolded together in parallel to handle the flowrates involved in the process and apparatus of the present invention. The single phase nature of the refrigerant makes it possible for these cores to be manifolded together relatively easily, without the difficulties encountered with two phase systems. However, aluminium plate-fin heat exchangers are constrained by the fact that the allowable design pressure decreases with increasing core size: in order to maintain the number of cores to a practical limit, the natural gas pressure should be below about 5.5 MPa. If higher pressures are desired, then it is preferred to use a spiral wound heat exchanger, a PCHE (printed circuit heat exchanger) or spool wound heat exchanger. Each heat exchanger in the series may comprise a plurality of heat exchanger cores in parallel. Each heat exchanger in the series may comprise more than one heat exchanger. In the preferred arrangement, the heat exchangers in the series are integrated into a single unit with appropriate inlet and outlet conduits. It is possible for the natural gas to be cooled by the refrigerant in further intermediate heat exchangers arranged upstream of the final heat exchanger. However, it is preferred to use only one intermediate heat exchanger, because this reduces the complexity of the equipment, and makes it possible to achieve lower pressure drops across the heat exchanger train. Whilst it is preferred that the refrigerant is divided into two streams, because this is the arrangement uses the least space, it is possible to divide the refrigerant into three, four or more streams. Each stream may be isentropically expanded in parallel with the other streams. It is also possible for one or more of the isentropic expansion steps to be carried out in stages using a series of isentropic expanders. It is preferred that the refrigerant comprises at least 50 mol % nitrogen, more preferably at least 80 mol % nitrogen, and most preferably substantially 100 mol % nitrogen. Nitrogen has a substantially linear warming curve over the temperature range −160° C. to 20° C. In one preferred embodiment the refrigerant comprises nitrogen and up to 10 vol %, preferably 5-10 vol %, methane. The refrigerant is ideally provided in a closed loop refrigerant cycle. The refrigerant could be, but need not be, taken from the stream of natural gas to be liquefied. Make-up refrigerant can be provided from a refrigerant source external to the refrigerant cycle. The apparatus according to the invention is preferably operated in accordance with a process described in our copending PCT application of even date entitled “Liquefaction Process”. According to this process there is provided a natural gas liquefaction process comprising passing natural gas through a series of heat exchangers in countercurrent relationship with a gaseous refrigerant circulated through a work expansion cycle, said work expansion cycle comprising compressing the refrigerant, dividing and cooling the refrigerant to produce at least first and second cooled refrigerant streams, substantially isentropically expanding the first refrigerant stream to a coolest refrigerant temperature, substantially isentropically expanding the second refrigerant stream to an intermediate refrigerant temperature warmer than said coolest refrigerant temperature, and delivering the refrigerant in the first and second refrigerant streams to a respective heat exchanger for cooling the natural gas through corresponding temperature ranges, wherein the refrigerant in the first stream is isentropically expanded to a pressure at least 10 times greater than, and usually more than 10 times greater than, the total pressure drop of the first refrigerant stream across said series of heat exchangers, said pressure being in the range 1.2 to 2.5 MPa. Preferably, the refrigerant is compressed to a pressure in the range 5.5 to 10 MPa. It is preferred that the first stream is isentropically expanded to a pressure in the range 1.5 to 2.5 MPa. The refrigerant in the first stream is preferably isentropically expanded to a pressure at least 20 times greater than the total pressure drop of the first refrigerant stream across said series of heat exchangers. It is possible to operate the process such that the first stream is isentropically expanded to a pressure at least 100 times greater than the total pressure drop of the first refrigerant stream across said series of heat exchangers. However, for most practical installations the refrigerant in the first stream will be isentropically expanded to a pressure not more than 50 times greater than the total pressure drop of the first refrigerant stream across said series of heat exchangers. In one particularly desirable embodiment the refrigerant is compressed to a pressure in the range 7.5 to 9.0 MPa, the refrigerant in the first refrigerant stream is expanded to a pressure in the range 1.7 to 2.0 MPa, and the refrigerant in the first stream is isentropically expanded to a pressure in the range 15 to 20 times the total pressure drop of the first refrigerant stream across said series of heat exchangers. The process is usually operated such that the temperature of each refrigerant stream after each isentropic expansion is greater than 1-2° C. above the saturation temperature of the refrigerant. Under these conditions, the refrigerant is well into the single phase, and is not close to saturation, there will be substantially no liquid in the isoentropically expanded refrigerant portions. However, there may be circumstances when it is desirable to operate the process such that a small amount of liquid is formed during expansion. For example, if the refrigerant comprises nitrogen with up to 10 vol % methane, preferably 5-10 vol % methane, then the process will be most efficient if some liquid is allowed to form during expansion. The ratio of the pressure of the refrigerant, immediately prior to the isentropic expansion, to the pressure of the refrigerant, immediately after the isentropic expansion, is preferably in the range 3:1 to 6:1, more preferably 3:1 to 5:1. In practice the best value for the intermediate refrigerant temperature depends upon the composition of the natural gas, and its pressure. However, in general the optimum value for the intermediate refrigerant temperature will be in the range −85° C. to −110° C. The apparatus according to the invention can be used to produce LNG on a commercial scale, typically 0.5 to 2.5 million tonnes of LNG per annum. In an offshore natural gas liquefaction apparatus comprising two heat exchanger trains each in a cold box, it is possible to produce around 3 million tonnes/annum of LNG. The heat exchanger trains, including power generators and other associated equipment can be fitted on a single platform of about 35 m by 70 m, having a weight around 9000 tonnes. This size is small enough for the liquefaction means to be installed on an offshore production platform or a floating production and storage vessel. The use of the present invention to liquefy gas at an offshore location has a number of advantages. The equipment is simple, particularly compared with the mixed refrigerant cycle; the refrigerant can be non-flammable; a relatively small amount of space is required; and the invention can be operated entirely with known, readily available equipment. BRIEF DESCRIPTION OF THE DRAWINGS Reference is now made to the accompanying drawings in which: FIG. 1 is a graph of temperature vs. rate of change of enthalpy showing the cooling curve of natural gas above and below critical pressure; FIG. 2 is a graph of temperature vs. rate of change of enthalpy showing the combined cooling curve for natural gas and nitrogen, and the warming curve for nitrogen, in a simple expander process; FIG. 3 is a schematic diagram showing one embodiment of apparatus for the process according to the present invention; FIG. 4 is a graph of temperature vs. rate of change of enthalpy showing the combined cooling curve for natural gas and nitrogen, and the warming curve for nitrogen for the process illustrated in FIG. 3, when the natural gas has a lean gas composition and the natural gas pressure is about 5.5 MPa; FIG. 5 is a graph of temperature vs. rate of change of enthalpy showing the combined cooling curve for natural gas and nitrogen, and the warming curve for nitrogen for the process illustrated in FIG. 3, when the natural gas has a rich gas composition and the natural gas pressure is about 5.5 MPa; FIG. 6 is a schematic diagram of another embodiment of apparatus for the process according to the present invention; FIG. 7 is a graph of temperature vs. rate of change of enthalpy showing the combined cooling curve for natural gas and nitrogen, and the warming curve for nitrogen for the process illustrated in FIG. 6, in which the natural gas has a lean gas composition and the natural gas pressure is about 5.5 MPa; FIG. 8 is a graph of temperature vs. rate of change of enthalpy showing the combined cooling curve for natural gas and nitrogen, and the warming curve for nitrogen for the process illustrated in FIG. 6, in which the natural gas has a rich gas composition and the natural gas pressure is about 7.7 MPa; FIG. 9 is a graph of temperature vs. rate of change of enthalpy showing the combined cooling curve for natural gas and nitrogen, and the warming curve for nitrogen for the process illustrated in FIG. 6, in which the natural gas has a rich gas composition and the natural gas pressure is about 8.3 MPa; FIG. 10 is a schematic diagram of one embodiment of a natural gas liquefaction apparatus according to the present invention; FIG. 11 is a schematic diagram of another embodiment of a natural gas liquefaction apparatus according to the present invention; FIG. 12 is a schematic diagram of another embodiment of a natural gas liquefaction apparatus according to the present invention; FIG. 13 is a schematic diagram of one embodiment of a part of the apparatus shown in FIGS. 10 to 12 ; and FIG. 14 is a schematic diagram of another embodiment of a part of the apparatus shown in FIGS. 10 to 12 . DETAILED DESCRIPTION OF THE INVENTION FIGS. 1 and 2 have already been discussed above. Referring to FIG. 3, an apparatus for liquefying natural gas is shown. Lean natural gas, at a pressure of about 5.5 MPa, is fed from a pre-treatment plant (not shown) to conduit 1 . The natural gas is conduit 1 comprises 5.7 mol % nitrogen, 94.1 mol % methane and 0.2 mol % ethane. Various pre-treatment arrangements are known in the art and the exact configuration depends on the composition of the natural gas recovered from the ground, including the level of undesirable contaminants. Typically the pre-treatment plant would remove carbon dioxide, water, sulphur compounds, mercury contaminants and heavy hydrocarbons. The natural gas in conduit 1 is fed to heat exchanger 66 , where it is cooled to 10° C. with chilled water. The exchanger 66 could be provided as part of the pre-treatment plant. In particular, the exchanger could be provided upstream of a water removal unit of the pre-treatment plant, in order to allow condensation and separation of the water contained in the natural gas, and to minimise the size of equipment. The natural gas exiting the heat exchanger 66 is fed to conduit 2 from where it is passed to the warm end of a series of heat exchangers comprising an initial heat exchanger 50 , two intermediate heat exchangers 51 and 52 , and a final heat exchanger 53 . The series of heat exchangers 50 to 53 serves to cool the natural gas to a temperature sufficiently low that it can be liquefied when flashed to a pressure (usually about atmospheric pressure) below the critical pressure of the natural gas. The natural gas in conduit 2 , at a temperature of about 10° C., is first fed to the warm end of the heat exchanger 50 . The natural gas is cooled in heat exchanger 50 to −23.9° C., and is passed from the cool end of the exchanger 50 to a conduit 3 . The natural gas in conduit 3 is fed to the warm end of the exchanger 51 , in which it is cooled to a temperature of −79.5° C. The natural gas exits the cool end of the exchanger 51 into a conduit 4 , from which it is fed to the warm end of the exchanger 52 . The exchanger 52 cools the natural gas to a temperature of −102° C., and natural gas exits the cool end of exchanger 52 into a conduit 5 . The natural gas in conduit 5 is fed to the warm end of exchanger 53 , in which it is cooled to a temperature of −146° C. The natural gas exits the cool end of the exchanger 53 into a conduit 6 . The natural gas in conduit 6 is fed to the warm end of a heat exchanger 54 , in which it is cooled to a temperature of about −158° C., and it exits the cool end of the exchanger 54 into a conduit 7 . The natural gas in conduit 7 , which is still at supercritical pressure, is fed to a liquid expansion turbine 56 in which the natural gas is substantially isentropically expanded to a pressure of about 150 kPa. In the turbine 56 the natural gas is liquefied, and is reduced in temperature to about −166° C. The turbine 56 drives an electrical generator G to recover the work as electrical power. The fluid exiting the turbine 56 is fed to a conduit 8 . This fluid is predominantly liquid natural gas, with some natural gas in the gaseous state. The fluid in conduit 8 is fed to the top of a fractionating column 57 . The natural gas feed in column 1 contains about 6 mol % of nitrogen: the fractionating column 57 serves to strip this nitrogen from the LNG. The stripping process is assisted by using the exchanger 54 to provide reboil heat transferred from the natural gas in conduit 6 . LNG is fed from the column 57 to conduit 67 , through which the LNG is fed to the cool end of the exchanger 54 . The exchanger 54 warms the LNG to a temperature of about −160° C.; the LNG exits the warm end of the exchanger 54 into conduit 68 , through which it is fed back to the column 57 . Stripped nitrogen gas is fed from the top end of the column 57 to the conduit 9 . The conduit 9 also contains a large percentage of methane gas, which is also stripped in the column 57 . The gas in conduit 9 , which is at a temperature of −166.8° C. and a pressure of 120 kPa, is fed to the cool end of a heat exchanger 55 , in which the gas is warmed to a temperature of about 7° C. The warmed gas is fed from the warm end of the exchanger 55 to a conduit 10 , from which it is fed to a fuel gas compressor (not shown). The methane fed through the conduit 10 is used to provide the bulk of the fuel gas requirements of the liquefaction plant. LNG is fed from the bottom of the column 57 to a conduit 11 and then to a pump 58 . The pump 58 pumps the LNG into a conduit 12 and on to a LNG storage tank (see FIGS. 10 and 11 ). The LNG in conduit 12 is at a temperature of −160.2° C. and a pressure of 170 KPa. The nitrogen refrigeration cycle which cools the natural gas to a temperature at which it can liquefy will now be described. Nitrogen refrigerant is discharged from the warm end of the exchanger 50 into a conduit 32 . The nitrogen in conduit 32 is at a temperature of 7.9° C. and a pressure of 1.14 MPa. The nitrogen is fed to a multistage compressor unit 59 , which comprises at least two compressors 69 and 70 , with at least one intercooler 71 , and an aftercooler 72 . The compressors 69 and 70 are driven by a gas turbine 73 . The cooling in the intercooler 71 and the aftercooler 72 is provided to return the nitrogen to ambient temperatures. The operation of the compressor unit 59 consumes almost all of the power required by the nitrogen refrigeration cycle. The gas turbine 73 can be driven by the fuel gas derived from conduit 10 . The compressed nitrogen is fed from the compressor unit 59 to a conduit 33 at a pressure of 3.34 MPa and a temperature of 30° C. The conduit 33 leads to two conduits 34 and 35 between which the nitrogen from the conduit 33 is split according to the power absorbed by the compressor. The nitrogen in the conduit 34 is fed to a compressor 62 in which it is compressed to a pressure of about 5.6 MPa, and is then fed from the compressor 62 to a conduit 36 . The nitrogen in the conduit 35 is fed to a compressor 63 in which it is compressed to a pressure of about 5.6 MPa, and is then fed from the compressor 63 to a conduit 37 . The nitrogen in both the conduits 36 and 37 is fed to a conduit 38 and then to an aftercooler 64 , where it is cooled to 30° C. The nitrogen is fed from the aftercooler 64 through a conduit 39 to a heat exchanger 65 in which it is cooled to a temperature of about 10° C. by chilled water. The cooled nitrogen is fed from the exchanger 65 to a conduit 40 , which leads to two conduits 20 and 41 ; the pressure in conduit 40 is 5.5 MPa. The nitrogen flowing through the conduit 40 is split between the conduits 20 and 41 : about 2 mol % of the nitrogen in conduit 40 flows through the conduit 41 . The nitrogen flowing through the conduit 41 is fed to the warm end of the heat exchanger 55 , where it is cooled to a temperature of about −122.7° C. The cooled nitrogen is fed from the cool end of the exchanger 55 to a conduit 42 . The conduit 20 is connected to the warm end of the heat exchanger 50 , whereby the nitrogen is fed to the warm end of the heat exchanger 50 . The nitrogen from conduit 20 is pre-cooled to −23.9° C. in the heat exchanger 50 , and is fed from the cool end of the heat exchanger 50 to a conduit 21 . The conduit 21 leads to two conduits 22 and 23 . The nitrogen flowing through the conduit 21 is split between the conduits 22 and 23 : about 37 mol % of the total nitrogen flowing through the conduit 21 is fed to the conduit 23 . The nitrogen in the conduit 22 is fed to a turbo expander 60 , in which it is work expanded to a pressure of 1.18 MPa and a temperature of −105.5° C. The expanded nitrogen exits from the expander 60 into a conduit 28 . The nitrogen in the conduit 23 is fed to the warm end of the heat exchanger 51 , in which it is cooled to a temperature of −79.6° C. The nitrogen exits the cool end of the exchanger 51 into a conduit 24 , which is connected to a conduit 25 . The conduit 42 is also connected to the conduit 25 , so that the cooled nitrogen from the heat exchangers 51 and 55 is all fed to the conduit 25 . The nitrogen in conduit 25 , which is at a temperature of −83.1° C., is fed to a turbo expander 61 in which it is work expanded to a pressure of 1.2 MPa and a coolest nitrogen temperature of −148° C. The expanded nitrogen exits from the expander 61 into a conduit 26 . The turbo expander 60 is arranged to drive the compressor 62 , and the turbo expander 61 is arranged to drive the compressor 63 . In this way the majority of the work produced by the expanders 60 and 61 can be recovered. In a modification the compressors 62 and 63 can be replaced with a single compressor that is connected to the conduits 33 and 38 . This single compressor can be arranged to be driven by the turbo expanders 60 and 61 , for example by being connected to a common shaft. The nitrogen in the conduit 26 is fed to the cool end of the exchanger 53 to cool the natural gas fed to the exchanger 53 from the conduit 5 by countercurrent heat exchange. In the heat exchanger 53 the nitrogen is warmed to an intermediate nitrogen temperature of −105.5° C. The warmed nitrogen exits the warm end of the exchanger 53 into a conduit 27 , which is connected to a conduit 29 . The conduit 28 is also connected to the conduit 29 , whereby the nitrogen from the warm end of the heat exchanger 53 is recombined with the nitrogen from the turbo expander 60 . The nitrogen in the conduit 29 , which comprises 100% of the total refrigerant flow, is fed to the cool end of the heat exchanger 52 . The nitrogen from the conduit 29 serves to cool the natural gas fed to the exchanger 52 from the conduit 4 by countercurrent heat exchange. The nitrogen flowing through the exchanger 52 is warmed by the natural gas to a temperature of −83.2° C., and exits from the exchanger 52 into a conduit 30 . The nitrogen is fed from the conduit 30 to the cool end of the heat exchanger 51 , in which it serves to cool the natural gas fed to the exchanger 51 from the conduit 3 , and serves to cool the nitrogen refrigerant fed to the exchanger 51 from the conduit 23 , by countercurrent heat exchange. The nitrogen fed to the heat exchanger 51 from the conduit 30 is warmed to about −40° C., and exits the exchanger 51 into a conduit 31 . The nitrogen is fed from the conduit 31 to the cool end of the heat exchanger 50 , in which it serves to cool the natural gas fed to the exchanger 50 from the conduit 2 , and serves to cool the nitrogen refrigerant fed to the exchanger 50 from the conduit 20 , by countercurrent heat exchange. The nitrogen fed to the heat exchanger 50 from the conduit 31 is warmed to 7.9° C., and exits the exchanger 50 into the conduit 32 . Reference is now made to FIG. 4, which is a temperature-enthalpy graph representing the process of FIG. 3, in which the natural gas has the lean composition described above. The graph shows a combined cooling curve for the natural gas and the nitrogen refrigerant and a warming curve for the nitrogen refrigerant. The cooling curve has a plurality of regions identified as 4 - 1 , 4 - 2 , 4 - 3 and 4 - 4 . The region 4 - 1 corresponds to cooling in the heat exchanger 50 : the gradient in this region is less than what would be the gradient of the cooling curve of natural gas alone over this region; in other words, the presence of the nitrogen refrigerant in the exchanger 50 lowers the gradient in this region. The region 4 - 2 corresponds to cooling in the heat exchanger 51 . The gradient is steeper here, due to the removal of part of the nitrogen refrigerant in conduit 22 ; the slope of the curve in region 4 - 2 is closer to the natural gas cooling curve than in region 4 - 1 . The region 4 - 3 corresponds to cooling in the heat exchanger 52 . The gradient here represents the natural gas cooling curve only, because there is no refrigerant being cooled in the heat exchanger 52 . This part of the curve represents the region over which liquefaction would take place if the pressure of the natural gas were below the critical pressure. The critical temperature is within the temperature range of region 4 - 3 . The region 4 - 4 corresponds to cooling in the heat exchanger 53 . The gradient is steepest in region 4 - 4 and represents the sub-cooling of the natural gas. If the natural gas were just below the critical pressure in this region, then it would be a liquid. The warming curve has two regions identified as 4 - 5 and 4 - 6 : the region 4 - 5 corresponds to refrigerant warming in the heat exchanger 53 ; and the region 4 - 6 corresponds to refrigerant warming in the heat exchangers 50 , 51 and 52 . The gradient of the warming curve in region 4 - 5 is greater than the gradient in the region 4 - 6 : this is due to the smaller mass flow rate of nitrogen in the heat exchanger 53 compared with the mass flow rate in the heat exchangers 50 , 51 and 52 . A point 4 - 7 represents the nitrogen temperature in the conduit 26 as it enters the cool end of the heat exchanger 53 . A point 4 - 8 represents the nitrogen temperature in the conduit 32 as it exits the warm end of the heat exchanger 50 . The points 4 - 7 and 4 - 8 set the end points of the nitrogen warming curve. The regions 4 - 5 and 4 - 6 intersect at a point 4 - 9 , which represents the nitrogen at the nitrogen intermediate temperature as it exits the heat exchanger 53 . It is highly advantageous that the point 4 - 9 is set as warm as possible within the constraints of the system. The nitrogen represented by the point 4 - 7 should be 1° C. to 5° C. cooler than the temperature of the natural gas exiting the heat exchanger 53 into the conduit 6 , and the nitrogen represented by the point 4 - 9 should be 1° C. to 10° C. cooler than the temperature of the natural gas entering the heat exchanger 53 from the conduit 5 ; these conditions are necessary to obtain a close match between the natural gas cooling curve and the nitrogen warming curve over the regions 4 - 4 and 4 - 5 . The temperature of the nitrogen represented by the point 4 - 9 should be below the critical temperature of the natural gas; this condition is also necessary to obtain a very close match between the natural gas cooling curve and the nitrogen warming curve over the regions 4 - 4 and 4 - 5 . Finally, the temperature of then nitrogen represented by the point 4 - 9 needs to be low enough that the straight line region between the point 4 - 9 and 4 - 8 does not intersect the natural gas/nitrogen cooling curve in the regions 4 - 1 , 4 - 2 or 4 - 3 . A point 4 - 10 on the nitrogen warming curve and 4 - 11 on the natural gas/nitrogen cooling curve represents the point of closest approach between the natural gas/nitrogen cooling curve and the nitrogen warming curve. An intersection of the two curves at the point 4 - 10 and 4 - 11 (or anywhere else) represents a temperature pinch in the heat exchangers. In practice, the point 4 - 9 should be chosen so that there is a 1° C. to 10° C. temperature difference between the natural gas/nitrogen being cooled at the point 4 - 11 and the nitrogen being warmed at the point 4 - 10 . The specific process parameters are heavily dependent upon the natural gas composition. The description in relation to FIGS. 3 and 4 was for a lean gas composition. The process could be used with a rich gas composition, comprising, for example, 4.1 mol % nitrogen, 83.9 mol % methane, 8.7 mol % ethane, 2.8 mol % propane and 0.5 mol % butane. Using such a composition, assuming a feed pressure in conduit 1 of about 5.5 MPa and a natural gas temperature in conduit 2 of 10° C., the pressures in the process are substantially the same as those described above with reference to the lean gas example. However, some of the temperatures are different. The natural gas emerging from heat exchanger 50 to conduit 3 is at −14° C., the natural gas emerging from heat exchanger 51 to conduit 4 is at −81.1° C., the natural gas emerging from heat exchanger 52 to conduit 5 is at −95.0° C., and the natural gas emerging from heat exchanger 53 to conduit 6 is at −146° C. As in the FIG. 3 embodiment, about 2.5 mol % of the total nitrogen flowing through the conduit 40 flows through the conduit 41 , while the rest flows through the conduit 20 . The nitrogen flowing through the conduit 41 emerges from the heat exchanger 155 into the conduit 42 at a temperature of about −105° C. The nitrogen in the conduit 22 is divided between the conduits 22 and 23 : about 33 mol % flows through the conduit 23 and about 67 mol % flows through the conduit 22 . The nitrogen refrigerant exiting the heat exchanger 50 to the conduit 21 is at −14° C. and the nitrogen refrigerant exiting the heat exchanger 51 to the conduit 24 is at −81.1° C. After mixing the nitrogen from the conduit 24 with the nitrogen from the conduit 42 , the nitrogen in the conduit 25 is at a temperature of −83.0° C. The nitrogen refrigerant from the conduit 22 is expanded in the turbo expander 60 to a temperature of 31 98.5° C., while the nitrogen refrigerant from the conduit 25 is expanded in the turbo expander 61 to a temperature of −148° C. The nitrogen refrigerant exits from the heat exchanger 53 to the conduit 27 at −98.5° C., is combined with the refrigerant from the conduit 28 , is passed through the heat exchanger 52 , and exits from the heat exchanger 52 to the conduit 30 at a temperature of −92.1° C. Subsequently, the nitrogen refrigerant exits from the heat exchanger 51 to the conduit 31 at a temperature of about −24.4° C. The temperature of the nitrogen exiting from the top of the column 57 to the conduit 9 is −164.1° C., and the temperature of the LNG product in conduit 12 is −158.4° C. FIG. 5 is similar to FIG. 4, and shows a temperature-enthalpy graph representing the process of FIG. 3, where the natural gas has the rich composition described above. The graph shows a combined cooling curve for the natural gas and the nitrogen refrigerant and a warming curve for the nitrogen refrigerant. The cooling and warming curves have a plurality of regions identified as 5 - 1 to 5 - 6 , which correspond to regions 4 - 1 to 4 - 6 respectively of FIG. 4, and have a plurality of temperature points 5 - 7 to 5 - 11 , which correspond to regions 4 - 7 to 4 - 11 respectively of FIG. 4 . The description above, relating the FIG. 4, also applies to FIG. 5, with the exception that in FIG. 5, the natural gas critical temperature is in the region 5 - 2 , rather than 5 - 3 . Referring now to FIG. 6, another embodiment of an apparatus for the present invention is shown. The FIG. 6 embodiment bears many similarities to the FIG. 3 embodiment, and the reference numerals given to the parts in FIG. 6 are exactly 100 higher than the equivalent parts in the FIG. 3 embodiment. The embodiment shown in FIG. 6 is preferred to the embodiment shown in FIG. 3, because fewer heat exchangers are required. Lean natural gas is fed from a pre-treatment plant (not shown) to conduit 101 . The natural gas in conduit 101 comprises 5.7 mol % nitrogen, 94.1 mol % methane and 0.2 mol % ethane, and is at a pressure of about 5.5 MPa. As discussed above, various pre-treatment arrangements are known in the art and the exact configuration depends on the composition of the natural gas recovered from the ground, including the level of undesirable contaminants. Typically the pre-treatment plant would remove carbon dioxide, water, sulphur compounds, mercury contaminants and heavy hydrocarbons. The natural gas in conduit 101 is fed to heat exchanger 166 , where it is cooled to 10° C. with chilled water. The exchanger 166 could be provided as part of the pre-treatment plant. In particular, the exchanger could be provided upstream of a water removal unit of the pre-treatment plant, in order to allow condensation and separation of the water contained in the natural gas, and to minimise the size of equipment. The natural gas exiting the heat exchanger 166 is fed to conduit 102 from where it is passed to the warm end of a series of heat exchangers 150 , 151 and 153 . The series of heat exchangers 150 to 153 cool the natural gas to a temperature sufficiently low that it can be liquefied when flashed to a pressure (usually about atmospheric pressure) below the critical pressure of the natural gas. It will be noted that in the embodiment of FIG. 6 there is no heat exchanger equivalent to the heat exchanger 52 of FIG. 3 . The natural gas in conduit 102 , at a temperature of about 10° C., is first fed to the warm end of the heat exchanger 150 . The natural gas is cooled in heat exchanger 150 to −41.7° C., and is passed from the cool end of the exchanger 150 to a conduit 103 . The natural gas in conduit 103 is fed to the warm end of the exchanger 151 , in which it is cooled to a temperature of about −98.2° C. The natural gas exits the cool end of the exchanger 151 into a conduit 104 , from which it is fed to the warm end of the exchanger 153 , in which it is cooled to a temperature of −146° C. The natural gas exits the cool end of the exchanger 153 into a conduit 106 . The natural gas in conduit 106 is fed to the warm end of a heat exchanger 154 , in which it is cooled to a temperature of about −158° C., and it exits the cool end of the exchanger 154 into a conduit 107 . The natural gas in conduit 107 , which is still at supercritical pressure, is fed to a liquid expansion turbine 156 in which the natural gas is substantially isentropically expanded to a pressure of about 150 kPa. In the turbine 56 the natural gas is liquefied, and is reduced in temperature to about −167° C. The turbine 156 drives an electrical generator G′ to recover the work as electrical power. The fluid exiting the turbine 156 is fed to a conduit 108 . This fluid is predominantly liquid natural gas, with some natural gas in the gaseous state. The fluid in conduit 108 is fed to the top of a fractionating column 157 . The natural gas feed in conduit 1 contains about 6 mol % of nitrogen: the fractionating column 57 serves to strip the nitrogen from the LNG. The stripping process is assisted by using the exchanger 154 to provide reboil heat transferred from the natural gas in conduit 106 . LNG is fed from the column 157 to conduit 167 , from where the LNG is fed to the cool end of the exchanger 154 . The exchanger 154 warms the LNG to a temperature of about −160° C.; the LNG exits the warm end of the exchanger 154 into a conduit 168 , through which it is fed back to the column 157 . Stripped nitrogen gas is fed from the top end of the column 157 to the conduit 109 . The conduit 109 also contains a large percentage of methane gas, which is also stripped in the column 57 . The gas in conduit 109 , which is at a temperature of −166.8° C. and pressure of 120 kPa, is fed to the cool end of a heat exchanger 155 , in which the gas is warmed to a temperature of about 7° C. The warmed gas is fed from the warm end of the exchanger 105 to a conduit 110 , from which it is fed to a fuel gas compressor (not shown). The methane fed through the conduit 110 is used to provide the bulk of the fuel gas requirements of the liquefaction plant. LNG is fed from the bottom of the column 157 to a conduit 111 and then to a pump 158 . The pump 158 pumps the LNG into a conduit 112 and on to a LNG storage tank (see FIGS. 10 and 11 ). The nitrogen refrigeration cycle which cools the natural gas to a temperature at which it can liquefy will now be described. Nitrogen refrigerant is discharged from the warm end of the exchanger 150 into a conduit 132 . The nitrogen in conduit 132 is at a temperature of about 7.9° C. and a pressure of 1.66 MPa. The nitrogen is fed to a multistage compressor unit 159 , which comprises at least two compressors 169 and 170 , with at least one intercooler 171 , and an aftercooler 172 . The compressors 169 and 170 are driven by a gas turbine 173 . The cooling in the intercooler 171 and the aftercooler 172 is provided to return the nitrogen to ambient temperatures. The operation of the compressor unit 159 consumes almost all of the power required by the nitrogen refrigeration cycle. The gas turbine 173 can be driven by the fuel gas derived from conduit 110 . The compressed nitrogen is fed from the compressor unit 159 to a conduit 133 at a pressure of 3.79 MPa. The conduit 133 leads to two conduits 134 and 135 between which the nitrogen from the conduit 133 is split according to the power absorbed by the compressor. The nitrogen in the conduit 134 is fed to a compressor 162 in which it is compressed to a pressure of about 5.5 MPa, and is then fed from the compressor 162 to conduit a 136 . The nitrogen in the conduit 135 is fed to a compressor 163 in which it is compressed to a pressure of about 5.5 MPa, and is then fed from the compressor 163 to conduit a 137 . The nitrogen in both the conduits 136 and 137 is fed to a conduit 138 and then to an aftercooler 164 , where it is cooled back to ambient temperatures. The nitrogen is fed from the aftercooler 164 through a conduit 139 to a heat exchanger 165 in which it is cooled to a temperature of 10° C. by chilled water. The cooled nitrogen is fed from the exchanger 165 to a conduit 140 , which leads to two conduits 120 and 141 . The nitrogen flowing through the conduit 140 is split between the conduits 120 and 141 : about 2 mol % of the nitrogen in conduit 140 flows through the conduit 121 . The nitrogen flowing through the conduit 141 is fed to the warm end of the heat exchanger 155 , where it is cooled to a temperature of about −123° C. The cooled nitrogen is fed from the cool end of the exchanger 155 to a conduit 142 . The conduit 120 is connected to the warm end of the heat exchanger 150 , whereby the nitrogen is fed to the warm end of the heat exchanger 150 . The nitrogen from conduit 120 is pre-cooled to −41.7° C. in the heat exchanger 150 , and is fed from the cool end of the heat exchanger 150 to a conduit 121 . The conduit 121 leads to two conduits 122 and 123 . The nitrogen flowing through the conduit 121 is split between the conduits 122 and 123 : about 26 mol % of the total nitrogen flowing through the conduit 121 is fed to the conduit 123 . The nitrogen in the conduit 122 is fed to a turbo expander 160 , in which it is work expanded to a pressure of 1.73 MPa and a temperature of −102.5° C. The expanded nitrogen exits from the expander 160 into a conduit 128 . The nitrogen in the conduit 123 is fed to the warm end of the heat exchanger 151 , in which it is cooled to a temperature of about −98.2° C. The nitrogen exits the cool end of the exchanger 151 into a conduit 124 , which is connected to a conduit 125 . The conduit 42 is also connected to the conduit 125 , so that the cooled nitrogen from the heat exchangers 151 and 155 is all fed to the conduit 125 . The nitrogen in conduit 125 , which is at a temperature of −100.3° C., is fed to a turbo expander 161 in which it is work expanded to a pressure of 1.76 MPa and a coolest nitrogen temperature of about −148° C. The expanded nitrogen exits from the expander 161 into a conduit 126 . The turbo expander 160 is arranged to drive the compressor 162 , and the turbo expander 161 is arranged to drive the compressor 163 . In this way the majority of the work produced by the expanders 160 and 161 can be recovered. In a modification the compressors 162 and 163 can be replaced with a single compressor that is connected to the conduits 133 and 138 . This single compressor can be arranged to be driven by the turbo expanders 160 and 161 , for example by being connected to a common shaft. The nitrogen in the conduit 126 is fed to the cool end of the exchanger 153 to cool the natural gas fed to the exchanger 153 from the conduit 104 by countercurrent heat exchange. In the heat exchanger 153 the nitrogen is warmed to an intermediate nitrogen temperature of −102.5° C. The warmed nitrogen exits the warm end of the exchanger 153 into a conduit 127 , which is connected to a conduit 129 . The conduit 128 is also connected to the conduit 129 , whereby the nitrogen from the warm end of the heat exchanger 153 is recombined with the nitrogen from the turbo expander 160 . The nitrogen is fed from the conduit 129 to the cool end of the heat exchanger 151 , in which it serves to cool the natural gas fed to the exchanger 151 from the conduit 103 , and serves to cool and nitrogen refrigerant fed to the exchanger 151 from the conduit 123 , by countercurrent heat exchange. The nitrogen fed to the heat exchanger 151 from the conduit 129 is warmed to about −57.9° C., and exits the exchanger 151 into a conduit 131 . The nitrogen is fed from the conduit 131 to the cool end of the heat exchanger 150 , in which it serves to cool the natural gas fed to the exchanger 150 from the conduit 102 , and serves to cool the nitrogen refrigerant fed to the exchanger 150 from the conduit 120 , by countercurrent heat exchange. The nitrogen fed to the heat exchanger 150 from the conduit 131 is warmed to 7.9° C., and exits the exchanger 150 into the conduit 132 . FIG. 7 is similar to FIG. 4, and shows a temperature-enthalpy graph representing the process of FIG. 6, where the natural gas has the lean composition described above. The graph shows a combined cooling curve for the natural gas and the nitrogen refrigerant and a warming curve for the nitrogen refrigerant. The cooling curve has a plurality of regions identified as 7 - 1 , 7 - 2 and 7 - 4 . The region 7 - 1 corresponds to cooling in the heat exchanger 150 : the gradient in this region is less than what would be the gradient of the cooling curve of natural gas alone over the region; in other words, the presence of the nitrogen refrigerant in the exchanger 150 lowers the gradient in this region. The region 7 - 2 corresponds to cooling in the heat exchanger 151 . The gradient is steeper here, due to the removal of part of the nitrogen refrigerant in conduit 122 ; the slope of the curve in region 7 - 2 is closer to the natural gas cooling curve than in region 7 - 1 . This part of the curve also represents the region over which liquefaction would take place if the pressure of the natural gas were below the critical pressure: the critical temperature is within the temperature range of region 7 - 2 . The region 7 - 4 corresponds to cooling in the heat exchanger 153 . The gradient is steepest in region 7 - 4 and represents the sub-cooling of the natural gas. Note that there is no region 7 - 3 in FIG. 7, because there is no heat exchanger 152 . The nitrogen warming curve has two regions identified as 7 - 5 and 7 - 6 : the region 7 - 5 corresponds to refrigerant warming in the heat exchanger 153 ; and the region 7 - 6 corresponds to refrigerant warming in the heat exchangers 150 and 151 . The gradient of the warming curve in region 7 - 5 is greater than the gradient in the region 7 - 6 : this is due to the smaller mass flow rate of nitrogen in the heat exchanger 153 compared with the mass flow rate in the heat exchangers 150 and 151 . A point 7 - 7 represents the nitrogen temperature in the conduit 126 as it enters the cool end of the heat exchanger 153 . A point 7 - 8 represents the nitrogen temperature in the conduit 132 as it exits the warm end of the heat exchanger 150 . The points 7 - 7 and 7 - 8 set the end points of the nitrogen warming curve. The regions 7 - 5 and 7 - 6 intersect at a point 7 - 9 , which represents the nitrogen at the nitrogen intermediate temperature as it exits the heat exchanger 153 . It is highly advantageous that the point 7 - 9 is set as warm as possible within the constraints of the system. The nitrogen represented by the point 7 - 7 should be 1° C. to 5° C. cooler than the temperature of the natural gas exiting the heat exchanger 153 into the conduit 106 , and the nitrogen represented by the point 7 - 9 should be 1° C. to 10° C. cooler than the temperature of the natural gas entering the heat exchanger 153 from the conduit 105 ; these conditions are necessary to obtain a very close match between the natural gas cooling curve and the nitrogen warming curve over the regions 7 - 4 and 7 - 5 . The temperature of the nitrogen represented by the point 8 . 9 should be below the critical temperature of the natural gas: this condition is also necessary to obtain a very close match between the natural gas cooling curve and the nitrogen warming curve over the regions 7 - 4 and 7 - 5 . Finally, the temperature of the nitrogen represented by the point 7 - 9 needs to be low enough that the straight line region between the point 7 - 9 and 7 - 8 does not intersect the natural gas/nitrogen cooling curve in the regions 7 - 1 or 7 - 2 . A point 7 - 10 on the nitrogen warming curve and 7 - 11 on the natural gas/nitrogen cooling curve represents the point of closest approach between the natural gas/nitrogen cooling curve and the nitrogen warming curve. An intersection of the two curves at the point 7 - 10 and 7 - 11 (or anywhere else) represents a temperature pinch in the heat exchangers. In practice, the point 7 - 9 should be chosen so that there is a 1° C. temperature difference between the natural gas/nitrogen being cooled at the point 7 - 11 and the nitrogen being warmed at the point 7 - 10 . The process of FIG. 6 will now be considered for a rich gas composition, comprising 4.1 mol % nitrogen, 83.9 mol % methane, 8.7 mol % ethane, 2.8 mol % propane and 0.5 mol % butane, using a natural gas feed pressure in conduit 1 of about 7.6 MPa and a natural gas temperature in conduit 102 of 10° C. Under these new conditions, the natural gas would exit from the heat exchanger 150 into the conduit 103 at a temperature of −8.0° C., the natural gas would exit from the heat exchanger 151 into the conduit 104 at a temperature of −87° C., and the natural gas would exit from the heat exchanger 153 into the conduit 106 at a temperature of −146° C. The nitrogen refrigerant exiting from the heat exchanger into the conduit 132 is at a temperature of 7.9° C. and a pressure of 2.31 MPa. The nitrogen refrigerant is compressed in the compressor unit 159 to a pressure of 6.08 MPa, and is then further compressed in the compressors 162 and 163 to a pressure of about 10 MPa. The nitrogen refrigerant in the conduit 140 is at a temperature of 10.0° C., as a result of the cooling in the aftercooler 164 and the heat exchanger 165 . About 2.2 mol % of the nitrogen flowing through the conduit 140 flows through the conduit 141 , while the remainder flows through the conduit 120 . The nitrogen flowing through the conduit 141 is reduced in temperature to about −108° C. in the heat exchanger 155 . The nitrogen refrigerant exiting the heat exchanger 150 into the conduit 121 it at a temperature of −8° C. About 25 mol % of the nitrogen in the conduit 121 flows through the conduit 123 , while the remaining 75 mol % flows through the conduit 122 . The nitrogen flowing through the conduit 123 emerges from the heat exchanger 151 at a temperature of −87° C., from where it flows into the conduit 125 along with the nitrogen from the conduit 142 : the temperature of the nitrogen in the conduit 125 is −88.7° C. The nitrogen flowing through the conduit 122 is expanded in the turbo expander 160 to a pressure of 2.39 MPa and a temperature of −90.5° C., and the nitrogen flowing through the conduit 125 is expanded in the turbo expander 161 to a pressure of 2.42 MPa and a temperature of −148° C. The nitrogen refrigerant emerging from the heat exchanger 153 into the conduit 127 is at a temperature of −90.5° C., and the nitrogen refrigerant emerging from the heat exchanger 151 into the conduit 131 is at a temperature of about −18° C. FIG. 8 is similar to FIG. 7, and shows a temperature-enthalpy graph representing the process of FIG. 6, where the natural gas has the rich composition described above, and is supplied at a pressure of about 7.6 MPa. The graph shows a combined cooling curve for the natural gas and the nitrogen refrigerant and a warming curve for the nitrogen refrigerant. The cooling and warming curves have a plurality of regions 8 - 1 to 8 - 6 , which correspond to regions 7 - 1 to 7 - 6 respectively of FIG. 7, and have a plurality of temperature points 8 - 7 to 8 - 11 , which correspond to temperature points 7 - 7 to 7 - 11 respectively of FIG. 7 . The description above, relating to FIG. 7, also applies to FIG. 8 . The process of FIG. 6 will now be considered for a rich gas composition, comprising 4.1 mol % nitrogen, 84.1 mol % methane, 8.5 mol % ethane, 2.6 mol % propane and 0.7 mol % butane, using a natural gas feed pressure in conduit 1 of about 8.25 MPa and a natural gas temperature in conduit 102 of 10° C. There is one slight modification to the process described above with respect to FIG. 6 : boil-off gas from LNG storage tanks is combined with the top product from column 157 in conduit 109 , and the combined contents of the conduit 109 are fed to the heat exchanger 155 . Under these new conditions, the natural gas would exit from the heat exchanger 151 into the conduit 104 at a temperature of −86.2° C., and would exit from the heat exchanger 153 into the conduit 106 at a temperature of −148.3° C. The nitrogen refrigerant exiting from the heat exchanger into the conduit 132 is at a temperature of 3.0° C. and a pressure of 1.77 MPa. The nitrogen refrigerant is compressed in the compressor unit 159 to a pressure of 4.97 MPa, and is then further compressed in the compressors 162 and 163 to a pressure of about 8.3 MPa. The nitrogen refrigerant in the conduit 140 is at a temperature of 10.0° C., as a result of the cooling in the aftercooler 164 and the heat exchanger 165 . About 1.7 mol % of the nitrogen flowing through the conduit 140 flows through the conduit 141 , while the remainder flows through the conduit 120 . The nitrogen flowing through the conduit 141 is reduced in temperature to about −143° C. in the heat exchanger 155 . The nitrogen refrigerant exiting the heat exchanger 150 into the conduit 121 is at a temperature of −7° C. About 31 mol % of the nitrogen in the conduit 121 flows through the conduit 123 , while the remaining 69 mol % flows through the conduit 122 . The nitrogen flowing through the conduit 123 emerges from the heat exchanger 151 at a temperature of −86.2° C., from where it flows into the conduit 125 along with the nitrogen from the conduit 142 ; the temperature of the nitrogen in the conduit 125 is −89.3° C. The nitrogen flowing through the conduit 122 is expanded in the turbo expander 160 to a pressure of 1.84 MPa and a temperature of −93.2° C., and the nitrogen flowing through the conduit 125 is expanded in the turbo expander 161 to a pressure of 1.87 MPa and a temperature of −152.2° C. The nitrogen refrigerant emerging from the heat exchanger 153 into the conduit 127 is at a temperature of −93.2° C. FIG. 9 is similar to FIG. 7, and shows a temperature-enthalpy graph representing the process of FIG. 6, where the natural gas has the rich composition described above, and is supplied at a pressure of about 8.25 MPa. The graph shows a combined cooling curve for the natural gas and the nitrogen refrigerant and a warming curve for the nitrogen refrigerant. The cooling and warming curves have a plurality of regions 9 - 1 to 9 - 6 , which correspond to regions 7 - 1 to 7 - 6 respectively of FIG. 7, and have a plurality of temperature points 9 - 7 to 9 - 11 , which correspond to temperature points 7 - 7 to 7 - 11 respectively of FIG. 7 . The description above, relating to FIG. 7, also applies to FIG. 9 . In FIG. 9 the minimum temperature difference between the two curves is 3.9° C., while in FIGS. 4, 5 , 7 and 8 , the minimum temperature difference is 2° C. Referring to FIG. 10 an embodiment of an apparatus for producing LNG is generally designated 500 . The apparatus comprises a floating platform in the form of a ship 501 , which carries a natural gas liquefaction plant 502 and LNG storage tanks 503 . The LNG is fed from the plant 502 to the storage tanks 503 via a conduit 504 . The natural gas is supplied to the plant 502 via a pipeline 505 , which extends to a natural gas rig 506 , and via a riser and manifold arrangement 510 , which extends from the ship 501 to the pipeline 505 . It is possible for the natural gas to be supplied from a plurality of said gas rigs 506 . A pre-treatment plant (not shown) may be provided for the natural gas, before it is fed to the plant 502 . The pre-treatment plant may be provided on the rig 506 , on a separate unit (not shown) or on the ship 501 . The ship 501 also includes accommodation 507 , mooring lines 508 , and means 509 for supplying LNG from the storage tanks 503 to an LNG carrier (not shown). Referring to FIG. 11 another embodiment of an apparatus for producing LNG is generally designated 600 . The apparatus comprises platform 601 , which is supported above the water level 607 by legs 609 , a natural gas liquefaction plant 602 and an LNG storage tank 603 . The LNG is fed from the plant 602 to the storage tank 603 via a conduit 604 . The storage tank 603 is supported by a concrete gravity base 610 , which rests on seabed 608 . The natural gas is supplied to the plant 602 via a pipeline 605 , which communicates with a natural gas rig 606 . It is possible for the natural gas to be supplied from a plurality of said gas rigs 606 . A pre-treatment plant (not shown) may be provided for the natural gas, before it is fed to the plant 602 . The pre-treatment plant may be provided on the rig 606 , on a separate unit (not shown), on the platform 601 or on the gravity base 610 . Means 611 is provided for supplying LNG from the storage tanks 603 to a LNG carrier (not shown). In a modification the apparatus 600 could be provided on the rig 606 . FIG. 12 shows a modification of the LNG apparatus 600 shown in FIG. 11 . In FIG. 12 the modified LNG apparatus is generally designated 600 ′ and comprises two spaced concrete gravity bases 610 ′, which rest on the seabed 608 ′, so that they project above the water level 607 ′. A liquefaction plant 602 ′ is provided on a platform 601 ′, which rests on the gravity bases 610 ′ and bridges the gap between the gravity bases 610 ′. An LNG storage tank 603 ′ is provided on each of the gravity bases 610 ′. The platform 601 ′ can be installed by supporting it on a barge (not shown): floating the barge into the gap between the gravity bases 610 ′ so that the platform 601 ′ projects over the upper surface of each gravity base 610 ′; lowering the barge so that the platform 601 ′ rests on the gravity bases 610 ′; and finally floating the barge out of the gap between the gravity bases 610 ′. Referring to FIG. 13, the natural gas liquefaction plants 502 , 602 and 602 ′ of FIGS. 10 to 12 are shown in more detail. In general, the components of the plant shown in FIG. 13 are similar to the components shown in FIGS. 3 and 6. Natural gas is supplied to conduit 450 of the plant at high pressure, which may be supercritical; the natural gas may have been pre-treated to remove contaminants using conventional processes. The natural gas in conduit 450 is fed to a heat exchanger 401 in which it is cooled with chilled water supplied from a chilled water refrigeration unit 415 . The heat exchanger 401 may, instead, be incorporated in the pretreatment process. The heat exchanger 401 may be a conventional shell and tube heat exchanger, or any other type of heat exchanger suitable for cooling natural gas with chilled water, including a PCHE. The cooled natural gas exits from the heat exchanger 401 to a conduit 451 , through which it is fed to a cold box 402 , where the gas is progressively cooled to a low temperature in a series of heat exchangers (not shown) within the box 402 . The heat exchanger arrangement in the cold box 402 may be the same as the arrangement of heat exchangers 50 , 51 , 52 and 53 shown in FIG. 3, or may be the same as the arrangement of heat exchangers 150 , 151 and 153 shown in FIG. 6 . The type of heat exchangers used depends on the pressure at which the natural gas is supplied. If the pressure is below about 5.5 MPa, then each heat exchanger comprises a number of aluminium plate heat exchangers manifolded in series. If the pressure is above about 5.5 MPa, then each heat exchanger comprises, for example, a spiral wound heat exchanger, a PCHE or a spool wound heat exchanger. However, when a spiral wound heat exchanger is used, the embodiment shown in FIG. 14 is more appropriate. The cold box 402 is filled with pearlite or rock wool to provide insulation. The are many advantages to using a the cold box 402 . First, it enables the majority of the cold equipment and piping to be contained within a single space that requires a much smaller plot area than if the equipment and piping were installed separately. The quantity of external insulation required is much less than if the equipment and piping were installed separately, and this reduces the cost and time of installation and future maintenance. In addition, the number of flanges required for connections of piping and equipment is reduced, because all the connections within the box are fully welded—this reduces the possibility of leaks from cold flange during normal operation and during cool-down and warm-up operations. The entire cold box installation can be constructed in a controlled industrial location and can be delivered to the construction site fully leak tested, dry and ready for commissioning—this would otherwise have to be done on the individual bits of equipment and piping in the field in remote locations and under less than ideal conditions. The cold box steel shell and insulation provides protection from the salt air environment in an offshore location, and affords a measure of fire protection for the equipment containing the hydrocarbon inventory. It should be noted that, when spiral wound heat exchangers are used, the first and intermediate exchanger bundles may both be included in a single vertical exchanger shell and may be installed separately to the cold box. In this case, the spiral wound heat exchanger is externally insulated and the cold box containing the remaining cold exchangers and vessel is significantly smaller. The sub-cooled natural gas is withdrawn from the cold box 402 , at its lowest temperature of about −158° C., into a conduit 452 , through which it is fed to a liquid or hydraulic turbine expander disposed within a suction vessel 413 in which the sub-cooled natural gas is work expanded to a low pressure (which is sub-critical), with a concomitant reduction in temperature and the formation of LNG. The work generated in the liquid or hydraulic turbine expander in the suction vessel 413 is used to turn an electrical generator; the electrical generator is also housed within the suction vessel 413 . It is possible for the liquid or hydraulic turbine expander and the suction vessel 413 to be replaced with a throttle valve: this will simplify the equipment, saving on capital costs and space, but there will be a small loss in process efficiency. The LNG exits the liquid or hydraulic turbine expander in the suction vessel 413 into a conduit 453 , which is fed back into the cold box 402 to a nitrogen stripper located within the cold box 402 . The nitrogen stripper within the cold box 402 may be the same as the nitrogen stripper 57 in FIG. 3, or the nitrogen stripper 157 in FIG. 6 . The cold flash gas from the top of the nitrogen stripper is then reheated in another heat exchanger in the cold box 402 , which may be the same as the heat exchanger 55 shown in FIG. 3, or the heat exchanger 155 shown in FIG. 6 . The reheated flash gash exits the cold box 402 into a conduit 454 , which is equivalent to the conduit 10 of FIG. 3, or the conduit 110 of FIG. 6 . The reheated flash gas in the conduit 454 is fed to a compressor unit 414 in which it is compressed to the required fuel gas system pressure. Cooling is provided in the compressor unit 414 by cooling water, which enters the unit 414 via conduit 455 and leaves the unit 414 via conduit 456 . The compressed fuel gas exits the compressor unit 414 into a conduit 457 . The compressor unit 414 may be an integrally geared multistage centrifugal compressor driven by an electric motor and complete with integral intercoolers and aftercoolers. Alternatively, the unit 414 may be an API specification centrifugal compressor with several compressor cases driven by an electric motor or a small gas turbine. The power requirements for the unit 414 may be provided by part of the fuel gas produced therein. The LNG product exits the nitrogen stripper into a conduit 458 , through which it is fed to a submerged pump 412 . The submerged pump 412 pumps the LNG into a conduit 459 , through which it is fed to storage tanks (see FIGS. 10 or 11 ). The refrigeration of the natural gas in the cold box 402 is provided by a nitrogen refrigeration cycle, the components of which will now be described. Nitrogen refrigerant exits the cold box 402 into conduit 460 , having been warmed to ambient temperatures by countercurrent heat exchange with the natural gas. The nitrogen in the conduit 460 is fed to a first stage compressor 405 where it is compressed to high pressure. The compressed nitrogen exits the compressor 405 into a conduit 461 , through which it is fed to an intercooler 462 , where the nitrogen is cooled with cooling water. The compressed nitrogen exits the intercooler 462 into a conduit 463 through which it is fed to a second stage compressor 406 , where it is compressed to an even higher pressure. The compressed nitrogen exits the compressor 406 into a conduit 464 , through which it is fed to an aftercooler 465 , where the nitrogen is cooled with cooling water. The compressors 405 and 406 may be multi wheel API type compressors; alternatively, axial flow compressors may be used if the suction pressure is low enough and/or the circulation rate is high enough. The compressors 405 and 406 may be provided in the form of a single compressor. The compressors 405 and 406 are driven by a gas turbine 403 . The gas turbine 403 is an aero-derivative type of gas turbine because of its smaller size and weight compared to the alternative industrial type gas turbines commonly used in onshore LNG plants. The temperature of the ambient air locations where the plant is located is often high, and this can substantially reduce the site rating of gas turbine 403 . This problem can be solved by cooling the gas turbine inlet air with chilled water in a heat exchanger 404 . The turbine air is taken in through an inlet manifold 467 of the turbine 403 , in which the heat exchanger 404 is disposed. The chilled water can be provided from the unit 15 . The high pressure nitrogen refrigerant exits the aftercooler 465 into a conduit 466 , from which the flow is subsequently divided between conduits 470 and 471 . The nitrogen flowing through the conduit 470 is fed to the compressor side of the expander/compressor unit 408 , while the nitrogen flowing through the conduit 471 is fed to the compressor side of the expander/compressor unit 409 . The compressed nitrogen exits the units 408 and 409 into conduits 472 and 473 respectively at an even higher, supercritical, pressure. The nitrogen flowing through the conduits 472 and 473 is recombined in a conduit 474 , through which it is fed to an aftercooler 410 , where it is cooled with cooling water. The nitrogen refrigerant exits the aftercooler 410 into a conduit 475 , through which it is fed to a heat exchanger 411 , where it is further cooled by countercurrent heat exchange with chilled water provided by the unit 15 . The heat exchangers 462 , 465 , 410 and 411 are all stainless steel PCHE exchangers; a closed circuit of fresh water is used for cooling in exchangers 462 , 465 and 410 . Alternatively, direct seawater cooling may be used for these exchangers, if suitable materials of construction are employed. The nitrogen refrigerant exits the heat exchanger 411 into a conduit 476 , through which it is fed to the cold box 402 , where it is pre-cooled in the series of heat exchangers in a similar manner to that shown in FIG. 3 or FIG. 6. A portion of the pre-cooled nitrogen (50-80 mol % of the total nitrogen flow) is withdrawn from the cold box 402 into a conduit 477 , through which it is fed to the turbo expander end of the expander/compressor unit 409 . The nitrogen in the expander compressor unit 409 is expanded to a lower pressure, with concomitant temperature drop. The work produced during this expansion stage is used to drive the compressor end of the expander/compressor unit 409 . The expander nitrogen exits the turbo expander of the expander/compressor unit into a conduit 478 . Another portion of the pre-cooled nitrogen (20-50 mol % of the total nitrogen flow) is withdrawn from the cold box 402 into a conduit 479 , through which it is fed to the turbo expander end of the expander/compressor unit 408 ; the nitrogen withdrawn into the conduit 479 has been cooled to a lower temperature than that withdrawn through the conduit 478 . The nitrogen in the expander compressor unit 408 is expanded to a lower pressure, with concomitant temperature drop. The work produced during this expansion stage is used to drive the compressor end of the expander/compressor unit 408 . The expanded nitrogen exits the turbo expander of the expander/compressor unit into a conduit 480 . The nitrogen in the conduits 478 and 480 is fed back to the series of heat exchanger within the cold box 402 , and serves to cool the natural gas entering the cold box 402 via the conduit 451 and to pre-cool the nitrogen entering the cold box 402 via the conduit 476 . The nitrogen flowing in the conduits 478 and 480 may follow the same path as the nitrogen in conduits 28 and 26 respectively in FIG. 3, or as the nitrogen in conduits 128 and 126 respectively in FIG. 6 . As explained above, the warmed nitrogen is subsequently withdrawn from the cold box 402 via the conduit 460 . The expander/compressor units 408 and 409 may be conventional radial flow expander units. If desired the expander of expander/compressor unit 409 may be replaced by two expander units in parallel or in series. All the expander/compressor units 408 / 409 may be installed on a single skid to save on plot area and interconnecting pipework; they may also have a common lube oil skid, thereby saving further in plot area and cost. Another possibility is to connect the expanders to a single compressor or a multi-stage compressor, this would avoid the need to split the nitrogen flow into conduits 470 and 471 . The chilled water refrigeration unit 415 comprises one or more standard, commercially available units, which can use refrigerants such as Freon, propane, ammonia, etc. The chilled water is circulated to the heat exchangers 401 , 404 and 411 in a closed circuit by centrifugal pumps (not shown). This unit has the advantage that it requires only a small inventory of refrigerant, and takes up very little space. The cooling water system is also a closed circuit system—it uses fresh water to allow the use of PCHE exchangers. The PCHE heat exchangers have the advantage that they are considerably smaller and cheaper than the conventional shell and tube heat exchangers normally used for this type of system. The nitrogen refrigeration system is a closed circuit system containing an initial inventory of dry nitrogen gas. This nitrogen must be replenished during normal operation, due to small losses of refrigerant from the circuit. These losses are caused by, for example, leaks to atmosphere from compressor seals and pipework flanges etc. A small amount of nitrogen is continuously added to the refrigeration system by nitrogen make-up unit (not shown), in order to compensate for the leakages. The nitrogen is extracted from the instrument air system on the plant. The make-up unit may be a commercially available unit, which can be of the membrane type or the pressure swing absorption type. FIG. 14 shows another embodiment of the apparatus shown in FIG. 13 . Many of the parts illustrated in FIG. 14 are identical to the parts illustrated in FIG. 13 —like parts have been designated with like reference numerals. The differences are as follows: The embodiment shown in FIG. 14 uses a series of heat exchangers in the form of a spiral wound heat exchanger (also known as a coil wound heat exchanger) 480 in place of the series of heat exchangers located within the cold box 402 in the apparatus shown in FIG. 13 . The heat exchanger 480 is provided with its own thermal insulation, so there is no need to locate it within a cold box. Cooled natural gas at supercritical pressure is withdrawn from the heat exchanger 480 via a conduit 482 , and is fed to a nitrogen stripper located within a cold box 484 . The nitrogen stripper within the cold box 484 may be the same as the nitrogen stripper 57 or 157 . The five refrigeration cycles described above, and shown in FIGS. 4, 5 , 7 , 8 and 9 , were simulated in order to make comparisons between the relative performance. The first cycle, as illustrated in FIG. 4, used lean gas at a pressure of 5.5 MPa cooled with refrigerant at 1.2 MPa. The total power requirement was found to be 17.1 kW/tonne natural gas produced/day. The second cycle, as illustrated in FIG. 5, used rich gas at a pressure of 5.5 MPa cooled with refrigerant at 1.2 MPa. The total power requirement was found to be 15.0 kW/tonne natural gas produced/day. The third cycle, as illustrated in FIG. 7, used lean gas at a pressure of 5.5 MPa cooled with refrigerant at 1.7 MPa. The total power requirement was found to be 17.4 kW/tonne natural gas produced/day. However, although the power requirement was higher than the first and second cycle, the increased pressure allows the heat exchanger sizes to be reduced. The fourth cycle, as illustrated in FIG. 8, used rich gas at a pressure of 7.6 MPa cooled with refrigerant at 2.4 MPa. The total power requirement was found to be 13.0 kW/tonne natural gas produced/day. The fifth cycle, as illustrated in FIG. 9, used rich gas at a pressure of 8.25 MPa cooled with refrigerant at 1.8 MPa. The total power requirement was found to be 14.6 kW/tonne natural gas produced/day. For comparison, the power requirement of a conventional propane pre-cooled mixed refrigerant cycle would be in the range 13 to 14 kW/tonne natural gas produced/day, and the power requirement of the simple nitrogen refrigeration cycle shown in FIG. 2 is about 27 kW/tonne natural gas produced/day. This shows that the process of the present invention is much more efficient than the simple refrigeration cycle. Whilst certain embodiments of the invention have been described herein, it will be appreciated that the invention may be modified. For the avoidance of doubt, the term “comprising” as used in this specification means “includes”.

4y

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority to, and the benefit of, Korean Patent Application No. 10-2007-0131664 filed in the Korean Intellectual Property Office on Dec. 14, 2007, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] (a) Field of the Invention [0003] The present invention relates to a variable valve system. [0004] (b) Description of the Related Art [0005] A variable valve lift (VVL) system changes a lift amount of an intake/exhaust valve of an engine according to driving conditions. Intake amount can be maximized at high speed/load and minimized at other times, to improve fuel efficiency and reduce exhaust gas. [0006] A variable valve timing portion is provided at one end of each of the intake camshaft and the exhaust camshaft. Cylinder deactivation portions are provided at some of the cylinders. One hydraulic pressure line is provided for the cylinder deactivation portions and another hydraulic pressure line is provided for the variable valve timing portions. [0007] However, when the cylinder deactivation portion continuously operates in a particular cylinder, an electric spark cannot be formed securely. Also, when the cylinder deactivation portion continuously operates in particular cylinder, the bore of the cylinder can be transformed. [0008] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. SUMMARY OF THE INVENTION [0009] A variable valve system includes a variable valve lifter for changing a first lift amount of one or more valves at a predetermined engine speed; a variable valve timing portion for controlling opening and closing timing of one or more valves; and a cylinder deactivation portion that changes a second lift amount of two or more valves in an alternating pattern. [0010] The variable valve lifter may control a rotation angle of a first control shaft to control a moving amount of a swing, arm, and/or control a rotation angle of a second control shaft to control a moving amount of a rocker arm. [0011] The first lift amount may be high, low, or medium. The second lift amount may be on or off. [0012] Two cylinder deactivation portions may be provided: a first one in a first cylinder, and a second one in a second cylinder. The system may alternately perform a first mode and a second mode. In the first mode, the first cylinder deactivation portion is operated, and the second is not. In the second mode, the first cylinder deactivation portion is not operated, and the second is. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is a first schematic diagram of a variable valve system according to an exemplary embodiment of the present invention. [0014] FIG. 2 is a second schematic diagram of a variable valve system according to an exemplary embodiment of the present invention. [0015] FIG. 3 is a third schematic diagram of a variable valve system according to an exemplary embodiment of the present invention. [0016] FIG. 4 is an arrangement table of a variable valve system according to an exemplary embodiment of the present invention. [0017] FIG. 5 is a drive mode arrangement table of a variable valve system according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0018] The present invention will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art will realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. [0019] As shown in FIG. 1 , an engine 105 includes a first cylinder (cyl. # 1 ) a second cylinder (cyl. # 2 ), a third cylinder (cyl. # 3 ), and a fourth cylinder (cyl. # 4 ). Also, an exhaust camshaft 115 and an intake camshaft 120 arc disposed to the cylinders. [0020] A first cylinder deactivation portion 217 a for exhaust and a second cylinder deactivation portion 217 b for intake are provided in the first cylinder (cyl. # 1 ). A third cylinder deactivation portion 217 c for exhaust and a fourth cylinder deactivation portion 217 d for intake are provided the second cylinder (cyl. # 2 ). A fifth cylinder deactivation portion 217 e and a sixth cylinder deactivation portion 217 f are provided in the third cylinder (cyl. # 3 ). A seventh cylinder deactivation portion 217 g and an eighth cylinder deactivation portion 217 h are provided in the fourth cylinder (cyl. # 4 ). [0021] A first hydraulic pressure line is provided to cylinder deactivation portions 217 a to 217 h. A check valve 100 is provided in the first hydraulic pressure line. Control valves (e.g., solenoid valves) are disposed on branch lines that are extended to the cylinder deactivation portions 217 a to 217 h. [0022] A variable valve timing portion 112 is disposed at one end of each camshaft 115 , 120 , and a second hydraulic pressure line is provided to the variable valve timing portions 112 . A control valve 110 is disposed in branch lines to each of the camshafts 115 and 120 . [0023] The deactivation portions 217 a to 217 h arc operated alternately. This prevents spark plugs disposed in any one particular cylinder from becoming fouled by oil. Also, bore transformation of a particular cylinder is prevented. [0024] Referring to FIG. 2 , a first variable valve lifter 405 a is provided in an exhaust port of the first cylinder (cyl. # 1 ) and a second variable valve lifter 405 b is provided in an intake port of the first cylinder (cyl. # 1 ). A third variable valve lifter 405 c and a fourth variable valve lifter 405 d are provided in the second cylinder (cyl. # 2 ). A fifth variable valve lifter 405 e and a sixth variable valve lifter 405 f are provided in the third cylinder (cyl. # 3 ). A seventh variable valve lifter 405 g and an eighth variable valve lifter 405 h are provided in the fourth cylinder (cyl. # 4 ). [0025] The variable valve lifters 405 a to 405 h control a swing arm (not shown) so as to control a lift amount of the valve in FIG. 2 . The valve controlled by the swing arm is adjusted in three steps of high, low, or medium. [0026] A first control shaft 410 a and a second control shaft 410 b are provided so as to control the variable valve lifters 405 a to 405 h. The first control shaft 410 a is provided at the exhaust side adjacent to the exhaust camshaft 115 , and the second control shaft 410 b is provided at the intake side adjacent to the intake camshaft 120 . [0027] Lifting distances of the exhaust valve and the intake valve are adjusted sequentially according to rotating positions of the first and second control shafts 410 a and 410 b. [0028] A third hydraulic pressure line is provided to the first and second control shafts 410 a and 410 b. A check valve 402 is provided in the third hydraulic pressure line. [0029] The first control shaft 410 a simultaneously controls valves of the exhaust side and the second control shaft 410 b simultaneously controls valves of the intake side. [0030] A first rotation angle control motor 400 a is provided at one end of the first control shaft 410 a, and a second rotation angle control motor 400 b is provided at one end of the second control shaft 410 b. [0031] Referring to FIG. 3 , a ninth variable valve lifter 505 a is provided in an exhaust port of the first cylinder (cyl. # 1 ), and a tenth variable valve lifter 505 b is provided in an intake port of the first cylinder (cyl. # 1 ). A eleventh variable valve lifter 505 c and a twelfth variable valve lifter 505 d are provided in the second cylinder (cyl. # 2 ). A thirteenth variable valve lifter 505 c and a fourteenth variable valve lifter 505 f are provided in the third cylinder (cyl. # 3 ). A fifteenth variable valve lifter 505 g and a sixteenth variable valve lifter 505 h are provided in the fourth cylinder (cyl. # 4 ). [0032] The ninth to sixteen variable valve lifters 505 a to 505 h control a rocker arm (not shown) so as to control a lift amount of a valve in FIG. 3 . The valve controlled by the rocker arm is adjusted in three steps of high, low, or medium. [0033] A third control shaft 510 a and a fourth control shaft 510 b are provided so as to control the variable valve lifters 505 a to 505 h. The third control shaft 510 a is provided at an exhaust side and adjacent to the exhaust camshaft 115 , and the fourth control shaft 510 b is provided at an intake side and adjacent to the intake camshaft 120 . [0034] Lifting distances of the exhaust valve and the intake valve are adjusted continuously according to rotating positions of the third and fourth control shafts 510 a and 510 b. [0035] A fourth hydraulic pressure line is provided to the third and fourth control shafts 510 a and 510 b. A check valve 502 is provided in the fourth hydraulic pressure line. The third control shaft 510 a simultaneously controls valves of the exhaust side and the fourth control shaft 510 b simultaneously controls valves of the intake side. [0036] A third rotation angle control motor 500 a is provided at one end of the third control shalt 510 a, and a fourth rotation angle control motor 500 b is provided at one end of the fourth control shaft 510 a. [0037] As shown in FIG. 4 , an 14 engine has four cylinders (cyl. # 1 , 2 , 3 , 4 ), where the second and third cylinders (cyl. # 2 , 3 ) are classified into a first group, and the first and fourth cylinders (cyl. # 1 , 4 ) are classified into a second group. The first group and the second group are alternately deactivated in the 14 engine. [0038] The variable valve lift system can be operated in different cylinders when cylinders are alternately deactivated. The variable valve lift system includes systems that are operated by a rocker arm or a swing arm. [0039] The first, third, and fifth cylinders (cyl, # 1 , 3 , 5 ) and the second, fourth, and sixth cylinders (cyl, # 2 , 4 , 6 ) are alternately deactivated in a V6 engine. The first, fourth, sixth, and seventh cylinders (cyl, # 1 , 4 , 6 , 7 ) and the second, third, fifth, and eighth cylinders (cyl, # 2 , 3 , 5 , 8 ) are alternately deactivated in a V8 engine. [0040] Referring to FIG. 5 , all cylinder deactivation portions (CDA) in group 1 and group 2 are operated in a fuel cut state. [0041] When the cylinder deactivation portions (CDA) in group 1 are operated in a range from 2000 to 3500 rpm, the variable valve lifter (VVL) can be operated in three steps of high, low, or medium in group 2 . Also, when cylinder deactivation portions (CDA) of group 2 are operated in a range from 2000 to 3500 rpm, the variable valve lifter (VVL) can be operated in three steps of high, low, or medium in group 1 . The variable valve lifters (VVL) of groups 1 and 2 are operated and the cylinder deactivation portions (CDA) of groups 1 and 2 are not operated from idle to 2000 rpm. [0042] At full load, the variable valve lifter (VVL) is operated in medium at a low speed and the variable valve lifter (VVL) is operated in high at a high speed. The cylinder deactivation portion (CDA) does not operate at a full load. [0043] While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

4y

FIELD OF THE INVENTION This invention relates to a method for reducing postprandial oxidative stress. BACKGROUND OF THE INVENTION Studies have linked certain dietary factors with atherosclerosis, a forerunner of coronary heart disease (Addis, P. B., Carr, T. P., Hassel, C. A., Hwang, Z. Z., Warner, G. J., Atherogenic and anti-atherogenic factors in the human diet. Biochem. Soc. Symp. 61, 259-271 (1995)). For example, a diet high in polyunsaturated fatty acids (PUFAS) may render low-density lipoprotein (LDL) more susceptible to peroxidation (Addis et al. 1995). The peroxidation of LDL can cause tissue damage leading to atherosclerosis (Sarkkinen, E. S., Uusitupa, M. I. J., Nyyssönen, K., Parviainen, M., Penttila, I., Salonen, J. T., Effects of two low-fat diets, high and low in polyunsaturated fatty acids, on plasma lipid peroxides and serum vitamin E levels in free-living hypercholesterolaemic men. European Journal of Clinical Nutrition (1993) 47: 623-630). The peroxidation of LDL is a result of the neutrophilic production of a superoxide anion radical or other reactive species (Steinberg, D., Parthasapathy, S., Carew, T. E., Khoo, J. C., Witztum, J. L. (1989) Beyond cholesterol. Modifications of low-density lipoprotein that increases its atherogenicity. New England Journal of Medicine 320: 915-924). The reactive species produced interact with PUFAS to form lipid peroxyl radicals, which subsequently produce lipid hydroperoxides and additional lipid peroxyl radicals (Steinberg et al. 1989). This initiates a peroxidative cascade which may eventually modify an essential part of the lipid's membrane, causing changes in membrane permeability and even cell death (Steinberg et al. 1989). Peroxidative degradation of LDL also leads to the formation of lipid oxidation products such as malondialdehyde (MDA) and other aldehydes which may be potentially toxic to the cell (Steinberg et al. 1989). Oxidative stress has been implicated in a variety of diseases and pathological conditions, including endothelial cell cytotoxicity, coronary heart diseases (such as thrombosis and hyperlipemia) and cancer. (Addis et al. 1995). Recent studies have shown that elevated lipid peroxidation levels (oxidative stress) may play a role in the pathogenesis of Alzheimer's disease which includes a group of neurodegenerative disorders with diverse etiologies, but the same hallmark brain lesions. Practico D. et al., Increased F 2- isoprostanes in Alzheimer's disease: evidence for enhanced lipid peroxidation in vivo. FASEB J. 1998 Dec.; 12 (15): 1777-1783. Clinical studies have established that elevated plasma concentrations of LDL are associated with atherosclerosis, a most prevalent cardiovascular disease and the principle cause of heart attack, stroke and vascular circulation problems (Sarkkinen et al. 1993). It is believed that a reduction of atherogenic lipid peroxides (which are transported in the LDL fraction of blood serum) can reduce the risk of atherogenesis (Mazur, A., Bayle, D., Lab, C., Rock, E., Rayssiguier, Y., Inhibiting effect of procyanidin-rich extracts on LDL oxidation in vitro. Atherosclerosis 145 (1999) 421-422). Antioxidants limit oxidative modification of LDL and consequently lower plasma concentrations of LDL, thereby acting as anti-atherogenic compounds (Sarkkinen et al. 1993). The oxidation of LDL has been reported as a model for testing the ability of polyphenols to act as antioxidants by breaking the peroxidative cascade described above (Rice-Evans, C., Plant polyphenols: free radical scavengers or chain-breaking antioxidants? Biochem. Soc. Symp. 61, 103-116 (1995)). Studies have reported that polyphenols can break the chain of the peroxidative process by intercepting free radicals before they reenter the cycle (Rice-Evans 1995). SUMMARY OF THE INVENTION This invention is directed to a method for reducing postprandial oxidative stress and associated pathologies by the dietary intake of cocoa polyphenols, including cocoa procyanidins. Cocoa procyanidins include monomers and dimers of catechin and epicatechin. Cocoa procyanidins can be obtained from several Theobroma cacao genotypes by the procedures discussed hereinafter. Cocoa procyanidins can also be obtained by synthetic methods described in PCT/US98/21392 (published as WO 99/19319 on Apr. 22, 1999) which is incorporated herein by reference. The oligomers synthesized using these methods may be linear, having the structure: where X is an integer from zero to sixteen or branched, having the structure: where A and B are independently integers from one to fifteen. It has been found that the dietary intake of an effective amount of cocoa procyanidins counteracts postprandial oxidative stress which has been linked to associated pathologies as described herein. Postprandial oxidative stress occurs following the ingestion of food products and has been linked with hyperlipidemia and increased risk of cardiovascular disease. Ursini F. et al., Postprandial plasma lipid hydroperoxides: a possible link between diet and atherosclerosis. Free Radic. Biol. Med. 1998 Jul. 15; 25 (2): 250-252. Consequently, the dietary intake of an effective amount of cocoa procyanidins counteracts these pathologies associated with postprandial oxidative stress. Measuring the formation of lipid oxidative products is one way to assay oxidative stress. Cocoa procyanidins reduce LDL peroxidation which consequently reduces the formation of lipid oxidation products which can be assayed as described herein. One such lipid oxidation product is malondialdehyde (MDA) which may be potentially toxic to the cell. Cocoa procyanidins can be found in foods common in the human diet, including chocolate. Epicatechin is a cocoa procyanidin abundant in chocolate. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the nanomoles (nmol) of malondialdehyde (MDA) in plasma at 2 and at 6 hours following ingestion of ½ bagel and a dark chocolate product which was made with enhanced levels of cocoa polyphenols and following ingestion of ½ bagel and a control chocolate containing lower levels cocoa polyphenols, including cocoa procyanidins (CPs). FIG. 2 shows the nanomoles (nmol) of malondialdehyde (MDA) in plasma at 2 and at 6 hours following ingestion of ½ bagel alone and following ingestion of ½ bagel with increasing quantities of semisweet chocolate which is typically high in cocoa polyphenols, including cocoa procyanidins (CPs). DETAILED DESCRIPTION OF THE INVENTION It has been found that the dietary intake of cocoa procyanidins counteracts oxidative stress as measured by reduction of LDL peroxidation. Consequently, there was reduction in the formation of LDL peroxidation products, such as malondialdehyde (MDA), which may be potentially toxic to the cell. Plasma lipid peroxides were measured photometrically using a thiobarbituric acid (TBA) reaction based on methods described in Yagi, K., Assay for blood plasma or serum, Methods in Enzymology 105: 328-331 (1984) Academic Press, Inc., Orlando, Fla. (Ed. L. Packer). MDA is a low molecular weight end-product that forms via decomposition of the products formed by lipid peroxidation. The MDA found in the plasma can be quantified using the Yagi et al. methods because at low pH and elevated temperature, MDA reacts with TBA to generate a fluorescent red adduct of MDA and TBA (1:2 ratio). The fluorescent intensity of the MDA:TBA adduct, which can be accurately quantified, parallels the concentration of the adduct. Hence, the amount of lipid peroxide produced can be fluorometrically measured using the TBA reaction, using an MDA standard. Substances other than the lipid peroxides can react with TBA and thereby distort results. These water-soluble substances are eliminated from the plasma sample by isolating the lipids using precipitation along with the serum protein using a phosphotungstic acid-sulfuric acid system. As shown below, levels of MDA decreased at 2 and at 6 hours following ingestion of semisweet chocolate high in cocoa polyphenols. Similarly, MDA levels decreased at 2 and at 6 hours following ingestion of dark chocolate high in cocoa polyphenols. The decreases were more pronounced when the intake of chocolate was increased. MDA levels also decreased (albeit not as much) when tested at 6 hours following ingestion of a dark chocolate which contained less of the cocoa polyphenols (that is, lower amounts of cocoa polyphenols than contained in the test chocolates). All of the chocolates used in the experiments described herein were made using the methods discussed hereinafter. All test products contained enriched levels of cocoa procyanidins. For example, the dark chocolate test product contained 147 mg total cocoa procyanidins (40.6 mg monomer) per 36.9 gram test product. The dark chocolate control product contained only 3.3. mg cocoa procyanidins (1.8 mg monomers) per 36.9 gram control product. The semisweet products contained 185 mg total cocoa procyanidins (45.3 mg monomers) per a 35 gram bag of semisweet chocolate bits. A single bag serving was consumed as the single dosage size. A two bag serving (70 grams) of semisweet chocolate bits product contained 370 mg total cocoa procyanidins and a three bag serving (105 grams) of semisweet chocolate bits product contained 555 mg total cocoa procyanidins. The quantities of cocoa procyanidin monomers and oligomers in the test products were measured by the analytical methods discussed hereinafter. Procyanidin levels were determined by analyzing levels of chocolate liquor or jet black cocoa powder and calculating the percentage of powder in the final product. The low levels of procyanidins in the control dark chocolate product precluded direct analysis. The chocolate liquor used to make the test products and the control product was a blend of cocoa beans, some of which were underfermented. The beans were prepared by the methods described in PCT/US97/15893 (published as WO 98/09533 on Mar. 12, 1998), which is herein incorporated by reference. Standard of Identity rules governed the different levels of chocolate liquor and sugar which were used to prepare semisweet versus dark chocolate. The semisweet chocolate had higher levels of chocolate liquor and sugar. The semisweet chocolate and the dark chocolate test products were used to demonstrate that even though the cocoa procyanidins were delivered using two different forms of test products, similar effects were exhibited by each. Methods for preparing cocoa mass are described in U.S. Pat. No. 5,554,645 (issued Sep. 10, 1996) which is herein incorporated by reference. Harvested cocoa pods were opened and the beans with pulp were removed for freeze-drying. The pulp was manually removed from the freeze-dried mass and the beans were subjected to the following manipulations. The freeze-dried cocoa beans were first manually dehulled and ground to a fine powdery mass with a TEKMAR Mill. The resultant mass was then defatted overnight by Soxhlet extraction using redistilled hexane as the solvent. Residual solvent was removed from the defatted mass by vacuum at ambient temperature. The chocolate liquor and/or cocoa solids can be prepared by roasting the cocoa beans to an internal bean temperature of 95° C. to 160° C., winnowing the cocoa nibs from the roasted cocoa beans, milling the roasted cocoa nibs into the chocolate liquor and optionally recovering cocoa butter and partially defatted cocoa solids from the chocolate liquor. The cocoa solids can be further defatted using conventional methods. Alternatively, partially defatted cocoa beans having a high cocoa polyphenol content, i.e., a high cocoa procyanidin content, can be obtained by processing without a bean or nib roasting step and without milling the beans to chocolate liquor. Even higher levels can be achieved if underfermented cocoa beans are used in this process. This method conserves the cocoa polyphenols because it omits the traditional roasting step. The method consists essentially of the steps of: (a) heating the cocoa beans to an internal bean temperature just sufficient to reduce the moisture content to about 3% by weight and loosen the cocoa shell, typically using a infra red heating apparatus for about 3 to 4 minutes; (b) winnowing the cocoa nibs from the cocoa shells; (c) screw pressing the cocoa nibs; and (d) recovering the cocoa butter and partially defatted cocoa solids which contain cocoa polyphenols including cocoa procyanidins. Optionally, the cocoa beans are cleaned prior to the heating step, e.g., in an air fluidized bed density separator. Preferably, the cocoa beans are heated to an internal bean temperature of about 100° C. to about 110° C., more preferably less than about 105° C. The winnowing can be carried out in an air fluidized bed density separator. The above process of heating the cocoa beans to reduce the moisture content and loosen the cocoa shell is disclosed in U.S. Pat. No. 6,015,913 issued Jan. 18, 2000 (to K. S. Kealey, et al.). which is herein incorporated by reference. The internal bean temperature (IBT) can be measured by filling an insulated container such as a thermos bottle with beans (approximately 80-100 beans). In order to maintain the temperature of the beans during transfer from the heating apparatus to the thermos, the insulated container is then appropriately sealed in order to maintain the temperature of the sample therein. A thermometer is inserted into the bean filled insulated container and the temperature of the thermometer is equilibrated with respect to the beans in the thermos. The temperature reading is the IBT temperature of the beans. IBT can also be considered the equilibrium mass temperature of the beans. The cocoa beans can be divided into four categories based on their color: predominately brown (fully fermented), purple/brown, purple, and slaty (unfermented). Preferably, the cocoa solids are prepared from underfermented cocoa beans, i.e., slaty cocoa beans, purple cocoa beans, mixtures of slaty and purple cocoa beans, mixtures of purple and brown cocoa beans, or mixtures of slaty, purple, and brown cocoa beans. More preferably, the cocoa beans are slaty and/or purple cocoa beans have a higher cocoa polyphenol content than fermented beans. The cocoa polyphenol content of cocoa ingredients, for example, the roasted cocoa nibs, chocolate liquor and partially defatted or nonfat cocoa solids, is higher when the cocoa beans or blends thereof have a fermentation factor of 275 or less. Preferably, these cocoa beans are used for processing into cocoa ingredients. The “fermentation factor” is determined using a grading system for characterizing the fermentation of the cocoa beans. For example, slaty beans are designated 1, purple beans as 2, purple/brown beans as 3, and brown beans as 4. The percentage of beans falling within each category is multiplied by the weighted number. Thus, the “fermentation factor” for a sample of 100% brown beans would be 100×4 or 400, whereas for a 100% sample of purple beans it would be 100×2 or 200. A sample of 50% slaty beans and 50% purple beans would have a fermentation factor of 150 [(50×1)+(50×20)]. Conventional processing techniques do not provide food products, especially confectioneries which adequately retain the cocoa polyphenol concentrations. However, high cocoa polyphenol food products may be prepared using conventional chocolate liquors or these high cocoa polyphenol chocolate liquors and/or conventional chocolate cocoa solids or high cocoa polyphenol cocoa solids by protecting the milk and/or sweetener with a pretreatment ingredient selected from the group consisting of an antioxidant, an emulsifier, a fat, a flavorant and mixtures thereof, before adding the cocoa ingredient. Preferred pretreatment ingredient is a mixture of cocoa butter and lecithin. Examples of high cocoa polyphenol food products include pet food, dry cocoa mixes, puddings, syrups, cookies, savory sauces, rice mixes and/or rice cakes, beverages, including cocoa beverages and carbonated beverages. Preferably, the high cocoa polyphenol foods are chocolate confectioneries, for example, dark chocolate, semisweet chocolate, sweet chocolate, milk chocolate, buttermilk chocolate, skim milk chocolate, mixed dairy milk chocolate and reduced fat chocolate. Cocoa polyphenols may be added to white chocolate and white chocolate coating to create products with high levels of cocoa polyphenols. These confectioneries may be either Standard of Identity chocolates or non-Standard of Identity chocolates. Preferable non-chocolate food products include nut-based products such as peanut butter, peanut brittle and the like. Also included are low-fat food products prepared with defatted or partially defatted nut meats. Cocoa procyanidins are also used in dietary supplements and pharmaceuticals. Also included are food products comprising at least one cocoa polyphenol and L-arginine. The procyanidin and L-arginine may be provided, respectively, by cocoa and/or nut procyanidins and an L-arginine containing component, such as a nut meat. The L-arginine may be derived from any available arginine source, e.g., Arachis hypogaea (peanuts), Juglans regia (walnuts), Prunus amygdalus (almonds), Corylus avellana (hazelnuts), Glycine max (soy bean) and the like. The nut may be nut pieces, a nut skin, a nut paste, and/or a nut flour present in amounts which provide the desired amount of L-arginine, which will vary depending upon the nut source. The L-arginine-containing ingredient may also be a seed, a seed paste, and/or a seed flour. The cocoa polyphenols, including cocoa procyanidins, may be synthetic or natural. The procyanidins may from a source other than cocoa beans. The food product may contain polyphenols, such as procyanidins, from a source other than cocoa, e.g., the polyphenols found in the skins of nuts such as those described above. Peanut skins contain about 17% procyanidins, and almond skins contain up to 30% procyanidins. In a preferred embodiment, the nut skins are used in the food product, e.g., the nougat of a chocolate candy. Polyphenols from fruits and vegetables may also be suitable for use herein. It is known that the skins of fruits such as apples and oranges, as well as grape seeds, are high in polyphenols. As used herein “food” is a material consisting of protein, carbohydrate and/or fat, which is used in the body of an organism to sustain growth, repair vital processes, and to furnish energy. Foods may also contain supplementary substances, such as, minerals, vitamins, and condiments (Merriam-Webster Collegiate Dictionary, 10 th Edition, 1993). As used herein “food supplement” is a product (other than tobacco) that is intended to supplement the diet that bears or contains one or more of the following dietary ingredients: a vitamin, a mineral, an herb or other botanical, an amino acid, a dietary substance for use by man to supplement the diet by increasing the total daily intake, or a concentrate, metabolite, constituent, extract or combination of these ingredients. (Merriam-Webster Collegiate Dictionary, 10 th Edition, 1993). When the term is used on food labels, “supplement” means that nutrients have been added in amounts greater than 50% above the U.S. Recommended Daily Allowance (“Understanding Normal and Clinical Nutrition, 3 rd Edition, Editors Whitney, Cataldo and Rolfes at page 525). As used herein “pharmaceutical” is a medicinal drug. (Merriam-Webster Collegiate Dictionary, 10 th Edition, 1993). The cocoa procyanidins in these products are part of a larger family of cocoa polyphenols which are present in cocoa beans. Suitable cocoa procyanidin-containing ingredients include roasted cocoa nibs or fractions thereof, chocolate liquor, partially defatted cocoa solids, nonfat cocoa solids, cocoa powder milled from the cocoa solids, and mixtures thereof. Preferably, the ingredients are prepared from underfermented beans since these beans contain higher amounts of cocoa polyphenols including the cocoa procyanidins. Cocoa procyanidins can be obtained from several Theobroma cacao genotypes which represent the three recognized horticultural races of cocoa, namely, Trinitario, Forastero and Criollo. See Engels, J. M. M., Genetic Resources of Cacao: A catalogue of the CATIE collection, Tech. Bull. 7, Turrialba, Costa Rica (1981). An extract containing cocoa polyphenols, including cocoa procyanidins, can be prepared by solvent extracting the partially defatted cocoa solids prepared from the underfermented cocoa beans or cocoa nibs having a fermentation factor of 275 or less, as described herein. METHODS Analytical Methods for the Quantification of Cocoa Procyanidins The analytical method described below was used to separate and quantify, by degree of polymerization, the procyanidin composition of the seeds from Theobroma cacao and of chocolate. The analytical method described below is based upon work reported in Hammerstone, J. F., Lazarus, S. A., Mitchell, A. E., Rucker R., Schmitz H. H., Identification of Procyanidins in Cocoa ( Theobroma cacao ) and Chocolate Using High-Performance Liquid Chromatography/Mass Spectrometry, J. Ag. Food Chem.; 1999; 47 (10) 490-496. The utility of the analytical method described below was applied in a qualitative study of a broad range of food and beverage samples reported to contain various types of proanthocyanidins, as reported in Lazarus, S. A., Adamson, G. E., Hammerstone, J. F., Schmitz, H. H., High-performance Liquid Chromatography/Mass Spectrometry Analysis of Proanthocyanidins in Foods and Beverages, J. Ag. Food Chem.; 1999; 47 (9); 3693-3701. The analysis in Lazarus et al. (1999) reported analysis using fluorescence detection because of higher selectivity and sensitivity. Composite standard stock solutions and calibration curves were generated for each procyanidin oligomer through decamer using the analytical method described below, as reported in Adamson, G. E., Lazarus, S. A., Mitchell, A. E., Prior R. L., Cao, G., Jacobs, P. H., Kremers B. G., Hammerstone, J. F., Rucker R., Ritter K. A., Schmitz H. H., HPLC Method for the Quantification of Procyanidins in Cocoa and Chocolate Samples and Correlation to Total Antioxidant Capacity, J. Ag. Food Chem.; 1999; 47 (10) 4184-4188. Samples were then compared with the composite standard to accurately determine the levels of procyanidins. Extraction The fresh seeds (from Brazilian cocoa beans) were ground in a high-speed laboratory mill with liquid nitrogen until the particle size was reduced to approximately 90 microns. Lipids were removed from 220 grams (g) of the ground seeds by extracting three times with 1000 milliliters (mL) of hexane. The lipid free solids were air dried to yield approximately 100 g of fat-free material. A fraction containing procyanidins was obtained by extracting with 1000 mL of 70% by volume acetone in water. The suspension was centrifuged for 10 minutes at 1500 g. The acetone layer was decanted through a funnel with glass wool. The aqueous acetone was then re-extracted with hexane (˜75 mL) to remove residual lipids. The hexane layer was discarded and the aqueous acetone was rotary evaporated under partial vacuum at 40° C. to a final volume of 200 mL. The aqueous extract was freeze dried to yield approximately 19 g of acetone extract material. Gel Chromatograhy Approximately 2 g of acetone extract (obtained above) was suspended in 10 mL of 70% aqueous methanol and centrifuged at 1500 g. The supernatant was semi-purified on a Sephadex LH-20 column (70×3 centimeters) which had previously been equilibrated with methanol at a flow rate of 3.5 mL/min. Two and a half hours after sample loading, fractions were collected every 20 minutes and analyzed by HPLC for theobromine and caffeine See Clapperton, J., Hammerstone, J. F., Romanczyk, L. J., Yow, S., Lim, D., Lockwood, R., Polyphenols and Cocoa Flavour, Proceedings, 16 th International Conference of Groupe Polyphenols, Lisbon, Portugal, Groupe Polyphenols: Norbonne, France, 1992; Tome II, pp. 112-115. Once the theobromine and caffeine were eluted off the column (˜3.5 hours), the remaining eluate was collected for an additional 4.5 hours and rotary evaporated under partial vacuum at 40° C. to remove the organic solvent. Then the extract was suspended in water and freeze dried. Purification of Procyanidin Oligomers by Preparative Normal-Phase HPLC The cocoa extract from above (0.7 g) was dissolved in (7 mL) mixture of acetone/water/acetic acid in a ratio by volume of 70:29.5:0.5, respectively. A linear gradient (shown in the table below) was used to separate procyanidin fractions using a 5 μm Supelcosil LC column (Silica, 100 Angstroms (Å); 50×2 cm) (Supelco, Inc., Bellefonte, Pa.) which was monitored by UV at a wavelength of 280 nanometers (nm). methylene chloride/ methanol/ time acetic acid/ water acetic acid/ water flow rate (minutes) (96:2:2 v/v)(%) (96:2:2 v/v)(%) (mL/min) 0 92.5 7.5 10 10 92.5 7.5 40 30 91.5 8.5 40 145 78.0 22.0 40 150 14.0 86.0 40 155 14.0 86.0 50 180 0 100 50 Fractions were collected at the valleys between the peaks corresponding to oligomers. Fractions with equal retention times from several preparative separations were combined, rotary evaporated under partial vacuum and freeze dried. Analysis of Purified Fractions by HPLC/MS To determine purity of the individual oligomeric fractions, an analysis was performed using a normal-phase high-performance chromatograph (HPLC) method interfaced with online mass spectrometry (MS) analysis using an atmospheric pressure ionization electrospray (API-ES) chamber as described by Lazarus et al. (1999), supra. Chromatographic analyses were performed on an HP 1100 series (Hewlett-Packard, Palo Alto, Calif.) equipped with an auto-injector, quaternary HPLC pump, column heater, diode array detector, and HP ChemStation for data collection and manipulation. Normal-phase separations of the procyanidin oligomers were performed on a Phenomenex (Torrance, Calif.) Luna silica column (25×4.6 mm) at 37° C. UV detection was recorded at a wavelength of 280 nm. The ternary mobile phase consisted of (A) dichloromethane, (B) methanol, and (C) acetic acid and water (1:1 v/v). Separations were effected by a series of linear gradients of B into A with a constant 4% of (C) at a flow rate of 1 mL/min as follows: elution starting with 14% of (B) into (A); 14-28.4% of (B) into (A), 0-30 min; 28.4-50% of (B) into (A), 30-60 min; 50-86% of (B) into (A), 60-65 min; and 65-70 min isocratic. HPLC/MS analyses of purified fractions were performed using an HP 1100 series HPLC, as described above, and interfaced to an HP series 1100 mass selective detector (model G1946A) equipped with an API-ES ionization chamber. The buffering reagent was added via a tee in the eluant stream of the HPLC just prior to the mass spectrometer and delivered with an HP 1100 series HPLC pump, bypassing the degasser. Conditions for analysis in the negative ion mode included 0.75 M ammonium hydroxide as a buffering reagent at a flow rate of 0.04 mL/min, a capillary voltage of 3 kV, a fragmentor at 75 V, a nebulizing pressure of 25 psig, and a drying gas temperature at 350° C. Data were collected on an HP ChemStation using both scan mode and selected ion monitoring (SIM). Spectra were scanned over a mass range of m/z 100-3000 at 1.96 seconds per cycle. The ammonium hydroxide was used to adjust the eluant pH to near neutrality via an additional auxiliary pump just prior to entering the MS. This treatment counteracted the suppression of negative ionization of the (−)-epicatechin standard due to the elevated concentration of acid in the mobile phase. The purity for each fraction was determined by peak area, using UV detection at a wavelength of 280 nm in combination with a comparison of the ion abundance ratio between each oligomeric class. Quantification of Procyanidins in Cocoa and Chocolate A composite standard was made using commercially available (−)-epicatechin for the monomer. Dimers through decamers were obtained in a purified state by the methods described above. Standard stock solutions using these compounds were analyzed using the normal-phase HPLC method described above with fluorescence detection at excitation and emission wavelengths of 276 nm and 316 nm, respectively. Peaks were grouped and their areas summed to include contributions from all isomers within any one class of oligomers and calibration curves generated using a quadratic fit. Monomers and smaller oligomers had almost linear plots which is consistent with prior usage of linear regression to generate monomer-based and dimer-based calibration curves. These calibration curves were then used to calculate procyanidin levels in samples prepared as follows: First, the cocoa or chocolate sample (about 8 grams) was de-fatted using three hexane extractions (45 mL each). Next, one gram of de-fatted material was extracted with 5 mL of the acetone/water/acetic acid mixture (70:29.5:0.5 v/v). The quantity of procyanidins in the de-fatted material was then determined by comparing the HPLC data from the samples with the calibration curves obtained as described above (which used the purified oligomers). The percentage of fat for the samples (using a one gram sample size for chocolate or one-half gram sample size for liquors) was determined using a standardized method by the Association of Official Analytical Chemists (AOAC Official Method 920.177). The quantity of total procyanidin levels in the original sample (with fat) was then calculated. Calibration was performed prior to each sample run to protect against column-to-column variations. EXAMPLE Human volunteers were instructed to fast overnight and to maintain low phytochemical intake the evening before the study. Phytochemicals are components in plants and foods derived from plants including many fruits, coffee, some teas, green peppers, garlic, onions, yogurt, bran, and cruciferous vegetables such as broccoli, cabbage, and cauliflower, etc. Blood was drawn from the subjects prior to consumption of any food. The subjects ingested either semisweet or dark chocolate. The two different chocolates were used to demonstrate that the cocoa polyphenols could be delivered in different forms and still exhibit the same effects. The chocolates had different levels of chocolate liquor and sugars as defined by the Standard of Identity rules for semisweet chocolate and dark chocolate. The chocolate liquor used to make these products was prepared from a blend of beans, some of which were underfermented. After the initial blood was drawn, the subjects were divided into two groups. One group was tested with the semisweet chocolate and the other group was tested with the dark chocolate. Both chocolates had enhanced levels of cocoa procyanidins. The conserved levels were obtained by the process described herein. For the dark chocolate experiment, the control subjects consumed a control bar which contained a low level of cocoa procyanidins, i.e., only 3.3 mg cocoa procyanidins (1.8 mg monomer) per 36.9 gram control product. The dark chocolate test product contained 147 mg total cocoa procyanidins (40.6 mg monomer) per 36.9 gram test product. Blood samples were drawn at 2 hours, after which another bagel was consumed. At 6 hours, another blood sample was drawn. FIG. 1 shows the nanomoles (nmol) of malondialdehyde (MDA) in plasma at 2 and at 6 hours following ingestion of ½ bagel with the dark chocolate test product or ½ bagel with the control chocolate product having the low cocoa procyanidins. As demonstrated by the data in FIG. 1, the higher the level of cocoa procyanidins ingested, the lower the levels of MDA in the plasma. The control chocolate product which some of the subjects ingested was prepared from jet black cocoa powder that was approximately ten to twelve percent fat that was completely alkalized. The powder was reconstituted in cocoa butter to give the proper percentage fat in the dark chocolate test bar (taking into account the 9.87% fat in the powder itself). The control bar was formulated with 49.335% sugar, 19.75% jet black cocoa powder, 27.344% cocoa butter, 2.61% anhydrous milk fat, 0.06% vanillin, 0.75% lecithin, 0.15% prova vanilla, and 0.001% orange oil. The level of monomer was calculated to be 1.8 mg per bar based upon the 3.3 mg per bar level of cocoa procyanidins and the known levels of fat. For the semisweet experiment, the control subjects consumed ½ bagel alone and no chocolate. The test group consumed ½ bagel with one of three different chocolates, each with a different level of cocoa procyanidins per bag. The first chocolate test product was a 35 gram semisweet chocolate product containing 185 mg total cocoa procyanidins (45.3 mg monomer) per 35 grams. The second chocolate test product was a 70 gram semisweet chocolate product containing 370 mg total cocoa procyanidins. The third chocolate test product was a 105 gram semisweet chocolate product containing 555 mg total cocoa procyanidins. Blood samples were drawn at 2 hours, after which another bagel was consumed. After 6 hours, another blood sample was drawn. FIG. 2 shows the nanomoles (nmol) of malondialdehyde (MDA) in plasma at 2 and at 6 hours following ingestion of ½ bagel alone and following ingestion of ½ bagel with increasing quantities of semisweet chocolate product, i.e., 35, 70 and 105 grams, containing increasing quantities of total cocoa procyanidins, i.e., 185, 370 and 555 mg. As demonstrated by the data in FIG. 2, the higher the level of cocoa procyanidins ingested, the lower the levels of MDA in the plasma. For the analysis of the thiobarbituric reactive substances (TBARS), a plasma sample (100 L) was mixed with 4% butylated hydroxytoluene (BHT) and then frozen overnight. The sample was then thawed at room temperature and a 100 L sample was mixed with 200 L sodium dodecyl sulfate (SDS). The following reagents were then added in sequence: 800 L 0.1 N hydrochloric acid (HCl), 100 L 10% 1,4-benzenedicarboxylic acid (PTA), and 400 L 0.7% thiobarbituric acid (TBA). The sample mixture was incubated in 95° C. water bath for 30 minutes. After cooling on ice, 1 ml of 1-butanol was added. The sample was then centrifuged for 10 minutes at 1800 g (3000 rpm) at 4 C. A 200 L aliquot of the butanol phase was assayed for extracted MDA by fluorometry. This quantity was used for each of the 96 wells of the plate which was read with excitation at 515 nm, slit 5 nm and emission at 555 nm, slit 5 nm. The effect of the cocoa procyanidin levels on the oxidative stress, as measured by the TBARS assay, was apparent at 2 hours and at 6 hours as shown by the change in total nanomoles of MDA per milliliters of plasma. Whether the cocoa procyanidins were present in the dark chocolate test product or in the semisweet chocolate test products made no difference. In addition, the effect was more pronounced as the amounts of total cocoa procyanidins consumed increased.

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a new or improved excavating apparatus of the type that employs a high pressure jet of fluid to excavate holes or trenches in soil, the loosened soil and fluid being drawn out of the excavation under vacuum. 2. Description of the Prior Art It is known to provide equipment of this type in the form of a self-propelled vehicle having a vacuum conduit leading to a tank in the vehicle and extending along the length of a boom which is pivoted on the vehicle about a horizontal axis to allow the cutting end of the conduit to be lowered vertically into the ground. Such apparatus however requires considerable headroom for the luffing movement of the boom, and there is always the danger that the boom may foul obstructions such as overhead power lines. SUMMARY OF THE INVENTION According to the invention there is provided a soil excavating apparatus comprising: a platform; an elongate boom mounted on said platform and having a free end that is angularly movable in a horizontal direction about said platform; an extendible flexible tubular conduit carried by said boom and having one end associated with said platform and connectable to a source of suction, said conduit extending longitudinally of the boom and having a portion leading to the second end thereof suspended to hang vertically from said boom at a spacing from said platform, said portion terminating in a tubular pipe that carries downwardly directed nozzle means near the lower end thereof; said conduit being extendible and retractable to selectively raise or lower said pipe independently of said boom, and said nozzle means being angularly shiftable about the axis of said pipe; the arrangement being such that said pipe can be lowered into the ground to excavate a hole by delivery of high pressure fluid through said nozzle means to loosen soil, and by removable of such loosened soil through said conduit by suction. Since the pipe at the end of the conduit can be raised or lowered independently of the boom, the latter can be "raiseless" i.e. arranged at a fixed height, being capable only of pivoting about a vertical axis. This enables the apparatus to work in situations where there is limited headroom and avoids the danger of the boom fouling overhead power lines. The apparatus is preferably provided on a vehicle, the platform being pivotally mounted on the top of the vehicle and the boom pivoting with the platform and extending radially therefrom so that it can be located anywhere throughout a wide angular arc around the vehicle. The boom is preferably also telescopically extensible and retractable to increase the effective operating area of the apparatus. The vehicle preferably includes a holding tank to receive displaced soil and spent water drawn through the conduit, the holding tank being placed under vacuum by a large capacity fan or the like. The bottom of the holding tank has sloping walls leading to an elongated trough wherein an auger is arranged to deliver soil from the holding tank to a discharge outlet. The vehicle preferably also includes water supply tanks one on each side of the holding tank. The water tanks are heated, e.g. by running the vehicle exhaust through them, so that the apparatus can operate in cold weather conditions. High pressure water drawn from these tanks can be further heated in a coil boiler or the like, thus enabling the apparatus to operate in frozen soil since the hot water will thaw the soil. The holding tank preferably includes blow-out panels to avoid destruction of the tank in the event that explosive gases are drawn into it, as can occur, for example, where excavation is being done in the vicinity of buried gasoline tanks or gas pipelines. BRIEF DESCRIPTION OF THE DRAWINGS The invention will further be described, by way of example only, with reference to the embodiment illustrated in the accompanying drawings wherein: FIG. 1 is a side view of a vehicle that includes soil excavating apparatus in accordance with the invention; FIG. 2 is a plan view thereof; FIG. 3 is a partial sectional view taken on the line III--III in FIG. 1; FIG. 4 is a sectional view taken on the line IV--IV in FIG. 3; FIG. 5 is an enlarged fragmentary plan view showing a detail; FIG. 6 is a fragmentary sectional view taken on the line VI--VI in FIG. 5; FIG. 7 is a partially sectioned view of a cutting tool portion of the apparatus; FIG. 8 is an underneath view of the cutting tool of FIG. 7; and FIG. 9 is a schematic view showing some details of the electro-hydraulic operating systems of the apparatus. DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in FIG. 1, the soil excavating apparatus is provided on a heavy duty self-propelled truck vehicle 10 having a forward cab portion 11 and a rearward payload portion 12. As shown more clearly in FIGS. 3 and 4, the portion 12 is of large box-like shape and incorporates a plurality of tanks, specifically a large holding tank 13 which extends the full length of the portion 12 and has sloping side walls 14 that converge downwardly to a longitudinally extending rounded bottom trough 15. Nested in the trough 15 is a longitudinally arranged auger 16 which is rotatably mounted and coupled to be driven by a motor 17 at its forward end. The motor 17 can be a hydraulic motor driven from a hydraulic system (FIG. 9) in the vehicle 10. The auger has a continuous helical flight 18 that leads to a discharge chute 19 at the rear of the vehicle, the discharge chute being closed by a pivoted lid 20 which may be hydraulically controlled. At the forward end of the roof 25 of the holding tank 13 is positioned a high volume air discharge fan 26 that communicates with the interior of the holding tank. On the upper side of the holding tank are four large circular doors 21 (FIG. 2) which normally close similarly shaped large openings in the roof 25, but which can be rapidly blown off in response to overpressure in the tank 13 so that in the event of an explosion in the tank, the doors 21 will blow out and rapidly relieve the overpressure thus saving the tank from destruction. On each side of the holding tank there is a clean water storage tank 27 which occupies the space between the holding tank side walls 14 and the outer walls 28 of the payload portion 12. This configuration largely insulates the holding tank from atmospheric conditions so that its contents do not readily freeze during cold weather operations. Suitable valves and conduits (not shown) are provided for supplying water to the tanks 27 and for removing it. The tanks 27 include heating means whereby heat can be applied to water stored in the tanks. As shown the heating means comprise tubes 29 schematically shown in FIGS. 3 and 4 by which hot exhaust gases from the engine of the vehicle can be ducted in indirect heat exchange relationship to the water in the tanks 27. The payload portion 12 provides a platform for a turntable 30 that is mounted on suitable thrust bearings (not shown) to rotate about a vertical axis 31a defined by a tubular hub 31, pivot about the hub 31 by an annular thrust bearing 32. The hub 31 is fixed relative to the tank roof 25 and opens into the interior of the holding tank 13. Attached to the turntable 30 is one end of a horizontally extending boom 40 having a free end 41 that extends beyond the confines of the vehicle 10. Together with the turntable boom can be pivoted from the position shown in FIG. 2 throughout a large range of angular movement, e.g. at least 340°, as indicated by the arrows 42 in FIG. 2. Rotation of the turntable and boom is controlled by the operator through a hydraulic motor 32 operating through a bevel gear drive 33 to a ring gear 34 carried by the turntable. The boom is also designed to be telescopically extensible, e.g. to a length about 8 feet in excess of what is shown, to increase the area that can be accessed by the apparatus. Telescoping is controlled by a hydraulic actuator 40a. The boom is of any suitable construction to provide a strong yet lightweight structure, and may as shown be fabricated as an open metal framework. The turntable 30 provides a rotary support for a reel 43 which is of large diameter and has wound therearound a portion of a flexible hose 44 one end of which extends radially inwardly and then curves to enter the tubular hub 31, this end of the hose being connected to the hub 31 by a rotary tubular seal 45. Rotation of the reel 43 relative to the turntable 30 is controlled by a hydraulic motor 35 acting through a sprocket and chain drive 36. The hose 44 can be of any suitable size, typically having an internal diameter of 6 or 8 inches. The hose is constructed of heavy duty rubber embodying a wire helix embedded between textile cords and encased in a black smooth abrasion and weather-resistant rubber. The hose is flexible yet relatively stiff so that it will not collapse under full vacuum conditions and yet can be bent to a relatively small bend radius, e.g. about 24 inches. The 6 inch internal diameter hose will have an outside diameter of about 6.75 inches and a weight of about 6.4 lbs/foot length. As noted, the reel 43 is rotatable about its vertical axis and carries thereon an excess length of the hose 44 which can be paid off or wound onto the reel by rotation of the latter. The hose 44 leaves the spool in a generally tangential direction and passes between guide rollers 50 arranged in pairs spaced along the boom (FIG. 5). At the free end 41 of the boom the hose passes over angularly offset sheaves 51 and changes direction from horizontal to vertical in an end section 52 that depends from the free end 41 of the boom 40. As best seen in FIG. 7, the end section 52 of the flexible hose 44 is connected through a power driven swivel coupling 53 to a co-axial cylindrical cutting tool pipe 54 of rigid material. The swivel coupling can be driven by a hydraulic motor, or as shown, by an electric motor 53a bolted on the top section 52 and driving the bottom section 54 via a V-belt and pulley drive 53b. The swivel joint 53 is constructed with internal bearings (not shown) that can be lubricated in conventional fashion. The pipe is of hard metal and has an open lower end which carries a peripheral protective plastics ring 55. This ring 55 prevents damage to the coating of underground utility pipes and the like should they be contacted by the lower end of the tool. Radially extending from the pipe near its lower end is an array of downwardly directed water nozzles 56 supplied with water through a high pressure water line 57 which passes within the pipe 54 and exits from the upper end of the pipe and is connected to a flexible section 58 which bridges the swivel coupling 53, the line 57 ultimately being connected to the storage tanks 27. As indicated by the arrow 59 in FIG. 8 the pipe 54 is rotatable about its vertical axis with respect to the hose 44. Such rotation is effected by the electric motor 53a controlled by the operator and causes the nozzles 56 to move angularly about the envelope of the pipe 54. The hydraulic control circuit for operation of the apparatus is schematically shown in FIG. 9 from which it will be seen that hydraulic fluid from a reservoir 64 is drawn and pressurized by two pumps 65a and 65b for delivery to the various hydraulic motors of the apparatus such as the fan motor 26, the auger drive motor 17, the pump motor 66, the swivel coupling motor 53a, the hydraulic actuator 40a, the boom rotating motor 32 and the hose reel motor 35. Operation of many of these motors and actuators is effected through a solenoid control valve 67 which can be remotely actuated by an operator who stands on the ground adjacent the cutting tool pipe 54 so that he can monitor its progress. The operation of the above described apparatus is as follows: The vehicle 10 is driven to the site to be excavated, and with the cutting tool pipe 54 suspended vertically above ground level, the boom 40 is swivelled horizontally about the axis 31a and extended as required by means of the actuator 40 to position the cutting tool pipe 54 in the desired location. The reel 43 is then rotated by the motor 35 and chain drive 36 to lower the bottom ring 55 against the ground, and simultaneously high pressure water is pumped through the nozzles 56 to loosen soil immediately below the cutting tool pipe 54, the pipe 54 being rotated so that the nozzles 56 can operate around the entire periphery of the tool. Prior to the water supply being initiated, the air discharge fan 26 is actuated to draw air out of the holding tank 13 creating a vacuum therein which is communicated through the tubular hub 31 and the hose 44 to draw loosened soil, air and water upwardly through the cutting tool pipe 54. As this is done, the cutting tool pipe 54 is progressively lowered into the hole created by the high pressure water jets delivered from the nozzles 56 until the hole has reached the desired depth. Throughout the cutting operation, the water and displaced soil are continuously drawn through the hose 44 into the holding tank 13. This action will create an essentially cylindrical hole to the desired depth into the soil. It will be appreciated that the apparatus can be utilized to excavate a continuous trench, this being done by movement of the boom and/or the vehicle together with control of the cutting nozzles to operate towards one side only of the hole, and repeated vertical reciprocations of the cutting pipe 54 as the movement progresses. It will be noted that the boom 40 of the above described and illustrated apparatus is "raiseless", i.e. its free end 41 does not have to move vertically to effect raising and lowering of the cutting tool pipe 54, but rather this is effected by advancing and retracting the hose 44 relative to the boom. This provides an important safety factor particularly when operating in locations with limited headroom, since there is no possibility of the boom being raised into contact with overhead obstructions such as power cables. The overall height of the machine illustrated including the hose reel 43 is approximately 3.8 meters, and the cutting tool 54 can be lowered to extend an excavation down to a depth of 6.5 meters or more below ground, without any need for making connections or adding pieces of pipe or hose. By the arrangement of the heating tubes 29 passing through the clean water tanks 27, the water is prevented from freezing thus enabling the apparatus to operate in cold climates. In the embodiment shown, a boiler 61 (FIG. 9) is included through which water from a pump 62 is directed en route to the discharge nozzles 56, the water being heated in the boiler 61 to almost its boiling point to enable operation of the apparatus in extremely cold temperature conditions at rates up to 300% faster than conventional equipment. This also enables use of the apparatus to do excavation in frozen ground around delicate utility lines. By mounting of the water nozzles 56 outwardly of the pipe 54 the interior of the latter remains essentially unobstructed, allowing for the free movement of return air and water to lift sizable pieces of debris or loosened soil. The cutting nozzles 56 are set back upwardly from the plastic ring 55 at the lower end of the cutting pipe which reduces the likelihood of damage being done to lines that are being uncovered. Excavations of the nature described often have to be effected in soil where there is a gas leak. The explosive damping doors 21 in the roof of the holding tank 13 enable the apparatus to operate safely under such conditions since in the event of an explosion in the holding tank, these doors will blow out, essentially avoiding damage to the machine or injury to workers. The provision of the unloading auger 16 in the holding tank 13 is an important feature, particularly where the excavation is being performed in contaminated soil. The auger provides the opportunity of controlling discharge of material from the tank 13. Thus rather than simply an uncontrolled dumping of the material, the auger enables the material to be off-loaded into barrels, plastic bags, small tanks etc. It is also possible to effect larger or irregularly shaped excavations by providing in place of the cutting tool 54 and hose 44, a hand held wand (not shown) coupled to the holding tank through a smaller hose and carrying water nozzles, movements of the wand being controlled manually by the operator.

4y

The present invention relates to monitoring cardiac-produced signals and more particularly to a cardiac monitoring device that includes circuitry for screening and/or eliminating undesirable artifact, to produce a signal indicative of a heartbeat and for monitoring said heartbeat indications. BACKGROUND OF THE INVENTION It is well known that expansion and contractions of muscle produce electrical signals that circulate upon the surface of a person's skin. Perhaps the most common are the expansions and contractions of the cardiac muscle, which are typically referred to as ECG signals. These ECG signals exhibit particular waveforms containing several distinct characteristics for each heartbeat. These characteristics, generally labeled P, Q, R, S and T, according to common medical usage, have allowed medical science to monitor a person's heartbeat or heartbeat count. Of the three positive peaks of a single heartbeat signal, the P, R and T pulses, it is usually the R peak that is the largest. Since it is necessary that ony one peak be detected for each heartbeat, a threshold detector can be employed in the simple case to distinguish between P and T waves, on the one hand, and R waves on the other. Accordingly, the R-wave peaks are available to trigger the threshold detector to generate heartbeat count and are often so used. At times, however, the P and/or T waves are taller than the R waves. In this instance utilization of a simple comparator operating directly on the unfiltered ECG waveform becomes erratic. One attempt at controlling this problem is be employing some form of filtering to attenuate the P and T waves in relation to the R waves, since R waves contain higher frequencies than other parts of the ECG waveform. Thus, for example, high-pass filters are used to attenuate P and T waves more than R waves. However, this solution is not always satisfactory. Additionally, pulse width discrimination is also used to detect the R wave and identify the ECG waveform from other muscle activity. However, as noted at the outset, all muscle tissue will emit electrical signals when expanding or contracting, the heart being only one of the many muscle groups of a person's body. Since other muscle groups will also emit electrical signals, it is desirable that the person remain relatively motionless while an ECG waveform is being obtained--particularly if the fidelity of the desired ECG waveform is to be as accurate as possible. When a person is in motion, however such as when exercising, the problem of monitoring the person's heartbeat becomes extremely difficult; the reason being that sensors placed on the person detecting the ECG signal also receive electrical signals produced by the other expanding and contracting muscles of the body--and other motion signals--termed "artifact". The heretofore known practices of limiting the frequency response characteristics of the ECG waveform and/or rejecting artifact by amplitude discrimination or pulse width discrimination to identify each heartbeat has been found to be generally insufficient, even when these techniques are used in combination. Therefore, it is desirable that additional techniques be found to allow accurate monitoring of a person's heartbeat during exercise to allow one to obtain reliable heartbeat information in the presence of such artifact. This is particularly true if the person wishes to exercise his or her cardiovascular system, yet keep his or her heartbeat within predetermined limits. SUMMARY OF THE INVENTION The present invention, therefore, provides apparatus that monitors a person's heartbeat during exercise. The invention allows the heartbeat or ECG signal to be detected even in the presence of motion, muscle or other artifact. According to the present invention, the ECG waveform is applied to positive and negative peak detector circuits which recognize excursions of the ECG waveform relative to predetermined DC levels and provide output signals indicative of such excursions beyond the DC levels. The output signal of the positive peak detector circuit is delayed a predetermined period of time and applied, with the output signal of the negative peak detector circuit, to a coincidence circuit for comparison. The coincidence circuit produces a signal that is indicative of a heartbeat. This signal is applied to counter circuitry and used to establish the relative beat-to-beat time period of the monitored heartbeat to determine whether the heartbeat rate repetition frequency is within predetermined limits. Indicia, responsive to the counter and coincidence circuits, provide the user with heartbeat information. Thus, it should be evident that the present invention provides a number of advantages not heretofore obtained by presently available heartbeat monitoring apparatus. First, the invention operates to reject troublesome artifact that can seriously impair or obscure heartbeart monitoring. This, in turn, allows the invention to monitor heartbeat activity while a person is exercising. The user (or his supervising physician) can set limits upon the stress placed upon his or her cardiovascular system through exercise and, while exercising, be assured that the cardiovascular system is sufficiently stressed without exceeding those limits. For a fuller understanding of the nature and advantages of the invention, reference should be had to the ensuing detailed description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of the heart monitoring apparatus according to the present invention; FIG. 2 is a more detailed schematic of the block diagram of FIG. 1; and FIGS 3A-3G illustrate typical waveforms involved in the operation of the apparatus of FIG. 2. DETAILED DESCRIPTION OF THE INVENTION An illustrative embodiment of the invention, in block diagram form, is shown in FIG. 1. Standard ECG amplifiers 12 and 14 are connected to a person 10 in the conventional manner via heartbeat sensing transducers A and B. The sensors are placed on the person 10 for picking up the varying cardiac potential and are coupled to the inputs of the ECG amplifiers 12 and 14. A third transducer G z is utilized as a reference electrode and is also coupled to the ECG amplifiers 12 and 14. The electrical ECG signals coupled to the ECG amplifiers 12 and 14 are differentially amplified to provide two substantially equal but complementary output signals that are communicated to peak detectors 16 and 18. The peak detectors 16 and 18 produce output pulses when the electrical signals applied thereto exceed predetermined DC levels. Thus, when the difference signal provided by ECG amplifier 16, illustrated in FIG. 1 as waveform 20, exceeds a DC level 22, the peak detector 16 produces a pulse 24 that is coupled via a delay circuit 26 to a coincidence gate 28. Similarly, the peak detector 18 produces an output pulse 24a when the (inverted) waveform 20a exceeds a predetermined DC level 22a. In this manner, the R and S wave portions of the received ECG signal are detected, compared and used to generate a pulse--the output of the coincidence gate 28--that is indicative of heartbeat occurrence yet free of troublesome artifact that may also have been present in the ECG signals. Coincidence gate 28 is connected to counter circuits 30. The signal provided by coincidence gate 28 is effectively compared by counter circuits 30 to predetermined time intervals to determine whether the heartbeat rate being monitored is above, below or within a specified range of preferred cardiac activity. The results of this determination are REST, EXERCISE and CAUTION signals which are displayed to the user via light-emitting diodes LED1-LED3 (FIG. 2). Thus, for example, the user may be informed his or her heartbeat rate is below a first rate--indicating a resting heartbeat (e.g., 80 beats per minute)--or, alternatively, that the user's heartbeat is above a predetermined limit and caution is advised. Referring now to FIG. 2, there is shown a more detailed schematic drawing of the block diagram of the invention illustrated in FIG. 1. As shown, the ECG amplifiers 12 and 14 include differential amplifiers 34 and 36, respectively. In turn, each of the differential amplifiers 34 and 36 include a conventional resistor/capacitor 38 and 40 configuration to limit the bandwidth of each amplifier to approximately 10-30 Hz to provide first artifact discrimination feature. The heartbeat sensing transducer A is applied to the positive input of the differential amplifier 34 and amplified relative to the signal obtained by the heartbeat sensing transducer B, which is applied to the negative input of the differential amplifier circuit 34. Similarly, the electrical activity obtained by the heartbeat sensing transducers A and B are applied to the differential amplifier circuit 36 in reverse configuration. Thereby, the electrical signals obtained by the heartbeat sensing transducers A and B appear at the respective amplifier outputs 42 and 44 of differential amplifiers 34 and 36 as two filtered, complementary difference signals. The outputs 42 and 44 of the differential amplifiers 34 and 36, respectively, are coupled to the peak detectors 16 and 18. Each peak detector is essentially identical in configuration and, therefore, only the peak detector 16 will be described, it being remembered that the description applies essentially also to the peak detector 18. Any difference between the two will be noted. The peak detector 16 includes a comparator 48 to which is coupled the output 42 of differential amplifier 34. A DC level-setting circuit 50 interconnects the output 42 and amplifier 48. The DC level-setting circuit 50 comprises a diode D1, voltage-divider resistors R1 and R2, and capacitor C1. The resistors R1 and R2 interconnect diode D1 with the reference heartbeat sensing transducer G z . The capacitor C1 interconnects the diode D1 with the circuit ground G. The level-setting circuit 50, in effect, holds the output 42 at a predetermined DC level. When the signal provided by the amplifier 34 exceeds the predetermined DC level set by the level-setting circuit 50, the comparator 48 will generate a (negative-going) pulse. The DC levels for peak detectors 16 and 18 are set by the threshold voltage of D1, in combination with the voltage divider network formed by the resistors R1 and R2. The capacitor C1 acts as a memory to expand the width of narrower pulses. The output of the differential amplifier 48 is applied to the delay circuit 26 comprising capacitor C 2 and resistor R3 in a simple differentiator configuration. The signal produced by the peak detector 16 is then communicated from the delay circuit 26 to the coincidence (NOR) gate 28. Coincidence gate 28 also receives the signal provided by the peak detector 18 which, as noted above, operates essentially the same as peak detector 16. The output of coincidence gate 28 is applied to, and used to trigger, a first monostable circuit 54. The pulse produced by the monostable 54 is communicated to a second monostable circuit 56 via output line 58. The output 60 of monostable 56 is coupled to an input of coincidence gate 28 and used as an inhibit signal of a predetermined time period, as will be described more fully below. The output 58 of monostable 54 is also used as a RESET signal and is coupled to the reset inputs of 10-stage (binary) counters 62 and 64. Applied to the clock (c) inputs of each 10-stage counter 62, 64 are digital pulses provided by variable clocks 68 and 70. Variable resistors R4 and R5 allow the frequency of each clock 68 and 70, respectively, to be adjusted and set as desired. The Q outputs of the last or tenth stage of counter 62 is a memory circuit 72 and from there to coincidence gates 66a and 66b. The memory circuit 72 is coupled to coincidence gate 66c via inverter I1. In similar fashion, the Q output of the last or tenth stage of counter 64 is coupled, via memory circuit 74, to coincidence gate 66a; and, via both the memory circuit 74 and inverter I2, to coincidence gates 66b and 66c. The outputs of coincidence gates 66a-66c are applied to light-emitting diodes LED1-LED3. The frequency of operation of clocks 68 and 70 provides a time base, measured by the 10-stage counters 62 and 64, against which the user's beat-to-beat heartbeat interval is measured. Thus, a first of two successive heartbeat indicating signals from coincidence gate 28 will cause, via monostable 54, the 10-stage counters 62 and 64 to be reset to their zero or initial states. The 10-stage counters 62 and 64 then commence counting the pulses provided by the clocks 68 and 70 until the next succeeding heartbeat indicating signal is communicated by coincidence gate 28. At the same time, the succeeding heartbeat indicating signal (e.g., the ENABLE signal provided by monostable 54) is compared to the states of the Q outputs of 10-stage counters 62 and 64 by coincidence gates 66a-66c. Depending upon the states of the Q outputs of the 10-stage counters 62 and 64, one of the indicators LED1-LED3 will be activated by the corresponding coincidence gate 66a-66c upon appearance of the ENABLE signal from monostable 54. A user is thereby provided with information as to his or her heartbeat--relative to predetermined standards. This will be discussed further below. For example, a heartbeat rate that is less than the frequency of operation of the clocks 68 and 70 divided by 512 is determined by coincidence of the inputs of coincidence gate 66a: The Q outputs of both 10-stage counters 62 and 64 being a logical one together with appearance of the ENABLE signal on output line 58 of the monostable circuit 54. Alternately, appearance of the ENABLE signal before the Q outputs of the 10-stage counters 62 and 64 have achieved a logical one will indicate a heartbeat rate that is above that limit set by the frequency of oscillation of clock 68. This latter situation is detected by the coincidence gate 66c. A heartbeat rate between these two limits is detected by the coincidence gate 66b, indicating that the heartbeat rate is within the desired limits. Depending upon which of the coincidence gates 66a-66c is activated upon occurrence of the ENABLE signal from monostable 54, one of the indicators LED1-LED3 with REST, EXERCISE and CAUTION signals, indicating a monitored heartbeat below, within or above the limits of the clock/counter time bases. Referring now to FIG. 3, the operation of the invention will be described. The heartbeat sensing transducers A, B and reference transducer G z are placed upon the skin of the person 10 (FIG. 1). Preferably, the heartbeat sensing transducers A and B are positioned so that the heart of the person 10 is positioned approximately between them. So located, the heartbeat sensing transducers A and B will sense and communicate electrical signals produced by cardiac activity to the ECG amplifiers 12 and 14. Additionally, the heartbeat sensing transducers will also receive artifact electrical signals produced by other muscle tissue. Thus, the signals received by the ECG amplifiers 12 and 14 are composite ECG signals, containing both the desired heartbeat information and unwanted artifact. These composite signals are differentially amplified by differential amplifiers 34 and 36, appearing at the outputs 42 and 44 as the electrical signals 76 and 78, illustrated in FIGS. 3A and 3B. As illustrated in FIGS. 3A and 3B, the signals provided by the differential amplifiers 34 and 36 are the complement of one another. The electrical signals 76 and 78 are respectively applied to the peak detectors 16 and 18. As mentioned above, the comparator 48 of the peak detector circuit will provide an output when the electrical signal appearing on the output line 42 exceeds the DC level, represented in FIG. 3A by the dotted line 80, set by the level-setting circuit 50. Of course, the DC level 80 would be set to detect the R-wave peak, but would also detect any artifact that was not filtered by the bandwidth discrimination of the circuitry of differential amplifier 34. Signals that do exceed the DC level 80, such as the R-wave peak of waveform 76, cause the comparator 48 to provide a negative-going pulse 84 (FIG. 3C). Similarly, the electrical signal appearing at output 44 of the differential amplifier 36 is applied to the comparator 49 of the peak detector 18. When the electrical signal appearing on the output 44 exceeds the DC level set by the level circuit 50a (indicated in FIG. 3B by the dotted line 82), the comparator 44a will provide an output in the form of the negative-going pulse 86 (FIG. 3E). Thus, the ECG waveform indicative of cardiac activity, which typically includes the R and S-wave peaks illustrated in FIG. 3A, will cause the respective comparators 48 and 49 to produce the negative-going pulses 84 and 86 shown in FIGS. 3C and 3E. The pulse 84 provided by the comparator 48 is first applied to the delay circuit 26, delayed a predetermined amount of time (Δt), and then communicated as a delayed pulse 85 (FIG. 3D) to coincidence gate 28. The second input of coincidence gate 28 receives the pulse 86 from comparator 49. Thus, if the electrical activity detected by the heartbeat sensing transducers A and B include a first positive-going pulse (the R-wave peak) followed, a predetermined amount of time, by a negative-going pulse (the S-wave peak) and such pulses exceed predetermined DC levels, such activity is determined to be a heartbeat. In this manner, other electrical activity included in the ECG waveform is filtered. Coincidence between the two signals provided by the comparators 48 (via delay circuit 26) and 49 (together with the INHIBIT signal from monostable 56) set at a logic zero will cause coincidence gate 28 to issue a signal which, in turn, is communicated to and fires the monostable 54. The monostable 54 thereupon provides, on output lines 58, a positive RESET/ENABLE signal 88, illustrated by FIG. 3F. The RESET/ENABLE signal 88 is used to trigger monostable 56 which, in turn, fires to produce a positive INHIBIT signal 90 (FIG. 3G) on output line 60. The INHIBIT signal is communicated to a third input of the coincidence gate 28. The INHIBIT signal 88 is used to block, for a predetermined time period, further signals indicative of a heartbeat being produced by coincidence gate 28. In effect, the INHIBIT signal produced by monostable 56 functions to provide further filtering of artifact which could be interpreted by the invention as a heartbeat pulse. For example, assume the time the INHIBIT pulse 90 remains in its logic zero state is 0.3 seconds. This is equal to the time interval between two successive heartbeats for a heartbeat rate of 200 beats per minute (i.e., 60/200 =0.3). Thus, the invention will correctly monitor heartbeat rates that are less than 200 beats per minute. For particular users, this limit (200 beats per minute) is realistic and any artifact resembling a heartbeat signal, yet would indicate a heartbeat rate higher than the 200 beats per minute maximum, is eliminated. Preferably, the time-out period of monostable is selectable; and, therefore, variable resistor/capacitor combination R6 and C3 are provided. The RESET/ENABLE signal provided by the monostable circuit 54 is also applied to the reset inputs of the 10-stage counters 62 and 64. Each counter, which had been counting clock pulses provided by clock 68 and 70 is reset to its initial or zero state by the RESET signal. If either of the Q outputs of the respective 10-stage counters 62 and 64 had become a logic one, indicating the presence of one or both limits, such information would be temporarily stored by the storage circuit 72 or 74, respectively. The binary state of the Q outputs of the 10-stage counters 62 and 64 (which, it will be remembered, are the Q outputs of the last or tenth stage of each counter) at the time of occurrence of the RESET signal provided by the monostable circuit 54, indicate one of three heartbeat conditions: (1) If both Q outputs of the 10-stage counters 62 and 64 are a logic zero, the heartbeat rate is greater than the limit set by the frequency of oscillation, divided by 512 (i.e., 2 9 ), of clocks 68 and 70; (2) if the Q outputs of the 10-stage counters 62 and 64 are a logic one and a logic zero, respectively, the heartbeat rate is within a predetermined range; and (3) if both Q outputs of the 10-stage counters 62 and 64 are logic ones, the heartbeat rate is less than the predetermined minimum set by the frequency of oscillation, divided by 512, of the clock 70. For example, assume that the variable resistor R4 has set the frequency of oscillation of clock 68 to be 1280 Hz. When the 10-stage counter 62 counts the pulses produced by clock 68, a first time base of 0.4 seconds (512 ÷1280 Hz) is established by transition from a logic zero to a logic one of the Q output of the 10-stage counter 62; a time base that is measured from detection of a heartbeat indication. The 0.4 second time base tranlates to a heartbeat rate limit of 150 beats per minute. Now assume that the variable resistor R5 is set so that the frequency of oscillation of clock 70 is 1024 Hz. The occurrnece of the output of the 10-stage counter 64 becoming a logic one determines, from the reset state, a time base of 0.5 seconds--which translates to a heartbeat rate of 120 beats per minute. With the variable resistors R4 and R5 set as described, the counter circuit 30 now has two predetermined time-base standards against which the beat-to-beat interval of a person's cardiac activity may be compared. Thus, for example, if the time period between any two successive heartbeat indications is less than the time from reset of the 10-stage counters 62 and 64 (caused by the first of the two indications) to Q=one, the heartbeat rate is determined as being greater than 150 beats per minute. On the other hand, if the Q output of the 10-stage counter 64 is a logic one when a heartbeat is detected, the rate is established as being less than 120 beats per minute. Similarly, if the Q outputs of the 10-stage counters 62 and 64 are a logic one and logic zero, respectively, when the second, succeeding heartbeat is detected, it is established that the heartbeat rate is somewhere between 120 and 150 beats per minute. As can be seen in FIG. 2, these conditions are detected by the coincidence gates 66a-66c. The ENABLE signal provides an indication of heartbeat presence. The Q outputs of the 10-stage counters 62 and 64 are coupled to the coincidence gates 66a-66c via the memory circuits 72 and 74. Depending upon the particular condition of the 10-stage counters 62 and 64 when the ENABLE signal appears, one of the indicators LED1-LED3 will be activated by its corresponding coincidence gate 66a-66c. Thus, if the heartbeat rate is less than 120 beats per minute in the above example, the LED1 indicator will be activated (both Q outputs of the 10-stage counters 62 and 64 are logic ones when the ENABLE signal appears); if the heartbeat rate is greater than 120 beats per minute but less than 150 beats per minute the LED2 indicator will be activated (the Q output of the 10-stage counter 62 is a logic one but the Q output of the 10-stage counter 64 is still a logic zero when the ENABLE signal appears); and the indicator LED3 will be activated when neither Q output of the 10-stage counters 62 and 64 have yet become a logic one when the ENABLE signal occurs. In summary, therefore, there has been disclosed apparatus for discriminating between a person's heartbeat and other artifact to produce a signal that is used to monitor the person's heartbeat rate. By peak detecting the R-wave and S-wave peaks, delaying the former a predetermined period of time and monitoring for coincidence, a significant amount of artifact activity is filtered. This allows one to monitor heart activity in the presence of motion such as exercise.

4y

BACKGROUND OF THE INVENTION Please cancel the originally filed specification and substitute the enclosed substitute specification. The original specification was based on an English language translation of the German Priority Document and, as such, contained some awkward grammar and syntax and in some ways did not conform to typical U.S. practice. The substitute specification conforms to the specification to typical U.S. practice. A marked-up copy of the original specification is enclosed for the Examiner's reference. No new matter has been added to the specification not found in the originally filed specification, claims, and drawings. The invention concerns a rear view mirror arrangement, especially an outside mirror for commercial vehicles. Outside mirrors of this kind and of variously different construction, are already known in the present state of the technology. A mirror pane is adjustably affixed by a pivoting mechanism to a housing part, which is appropriately connected to the body of the vehicle, allowing the mirror to swing in reference to the housing part. The housing part is, as a rule, a solid plastic part, produced by injection molding. It is generally of a basin-like construction in which further mirror components or corresponding connection points for additions are installed. In particular, for large truck and bus mirrors, the carrying structure for outside mirrors is based on tubing or plates, which are affixed directly to the mirror holder which projects toward the vehicle body. This construction is disclosed by EP-A-0 590 510. The housing part serves then as a covering of the back side of the mirror plate and supports the pivoting mechanism. The housing also provides a streamlined sheathing of the outside mirror. Such construction is extremely expensive and heavy. A problem with this tube and plate construction is found in that relatively strong vibrations occur in the rearview mirror assembly during the operation of the vehicle. In order to reduce these vibrations, EP 0 865 967 A2 proposes a carrying tube structure, encased in a foamed molded part. Again, the disadvantage of this is that the entire carrying structure is very heavy. A very light design, which is adaptable to smaller mirrors, is taught by DE 44 29 604 A1. In this case, the tube construction is fully dispensed with and the foam element itself remains as the carrying structure. For this purpose, a gradiated foam is employed as a one-piece element or the carrier comprises several shells. OBJECTIVES AND SUMMARY OF THE INVENTION The objective of the present invention is to make available a sufficiently stable rearview mirror, which, in any case, exhibits the least possible tendency to vibrate. This purpose is accomplished by the features of the invention. Because at least one hollow space in the carrier is filled with a filling material(also called fill material hereafter), which is composed of material other than that of the carrier, or which material possesses a density other than that of the carrier, it is possible to specifically target the vibratory tendencies of the carrier by the appropriate choice of filling material. Additionally the filling material can also lead to an improved stability of the carrier, insofar as the filling material binds itself to the inner wall of the carrier or the interior surface of the hollow space. A plurality of hollow spaces within the carrier can purposely be provided at specific locations. The choice of the locations is done empirically, wherein the effort is made to bring about the greatest possible damping of the vibration. The carriers with hollow spaces can be made by injection molding, foam processing such as a thermoplastic, integral foam, or blow molding, including extrusion blow molding. In these methods, for the applicable shape of the hollow spaces, negative shapes are inserted, which are patterned after the desired form. In accord with an advantageous embodiment of the invention, for additional stabilization, stiffening structures are installed in at least one hollow space. This, in a first instance, can be brought about by inserting a separate component into a hollow space, or, in a second instance, in that the wall structure of the hollow space is provided with reinforcing ribs. In accord with another advantageous embodiment of the invention, the filling material in the hollow spaces consists of plastic foam, such as polyurethane foam, gradient foam, multi-component hard foam and the like, which binds itself firmly with the interior walls of the hollow spaces, thus increasing the stability of the carrier. Moreover, by means of an appropriate choice of foam density, or by the resilience thereof, the vibratory behavior of the carrier can be so positively affected that during commercial travel, the inevitable vibrations are strongly damped and, as a result, the abrasion therefrom is reduced. Additionally, or alternatively, it is possible to fill in the hollow space or spaces, or a part thereof, with a viscous material, in particular a gel or a gelatin-like material. In this way, likewise, the vibrations and the damping are specifically influenced. In accord with a further advantageous embodiment of the invention, a granulate and/or sand may be additionally or alternatively placed in the hollow spaces or in a part thereof. In this way, the fill material can be comprised exclusively of sand or granulate, or a mixture thereof, or yet of a mixture with the above described gel, gelatin or foam. Once again, the stability is favored in a positive way and again the specific vibratory and damping characteristics can be advantageously controlled with attention to specifics. BRIEF DESCRIPTION OF THE DRAWINGS Further details, features and advantages of the invention will become evident from the following description of preferred embodiments. The description is made with the aid of the drawing. There is shown in: FIG. 1 a a schematic sideview of a first embodiment of the invention with a carrier in the form of a blown plastic, hollow body with a single, continuous hollow space, which is incorporated in foam, FIG. 1 b a sectional view along the line A—A in FIG. 1 a, FIG. 2 a a perspective view of a second embodiment of the invention with a rearview mirror which possesses a carrier with of two integral support arms, FIG. 2 b a sectional view along the line B—B in FIG. 2 a, FIG. 3 a schematic sideview of a third embodiment of the invention with a carrier in the form of a plastic, hollow body with a plurality of hollow spaces, and FIG. 4 a partial sectional view of a fourth embodiment of the invention with a carrier constructed of a blown plastic, hollow body with additional stiffening structural members. DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made in detail to the presently preferred embodiment of the present invention, an example of which is illustrated in the drawings. The example is provided by way of explanation of the invention and is not meant as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be used on another embodiment to yield yet a third embodiment. Accordingly, it is intended that the present invention include such modifications and variations. The FIGS. 1 a and 1 b show, in a schematic manner, a first embodiment of the invention. The rearview mirror incorporates a carrier 2 in the form of a plastic hollow body 2 , which was blow formed from an extruded plastic blank. The carrier 2 possesses a closed wall 4 , which envelopes a hollow space 6 . On the vehicle end of the plastic hollow body 2 are provided holes for screws 8 . These fastening means bind the rearview mirror arrangement to the body of the vehicle. On the end of the plastic hollow body 2 remote from the said body, in respective recesses are mounted a first mirror 10 and a second mirror 12 . Both mirrors include, respectively, an adjustment mechanism 14 , 16 , by means of which the corresponding mirror is mounted on the plastic hollow body 2 . The wall 4 of the plastic hollow body 2 is made thicker at positions of greater stress than is the corresponding thickness at positions of less stress (not shown). As is indicated in FIG. 1 b by means of dotted areas, the entire hollow space 6 is foam filled with a foam material 18 , this being, for instance, a polyurethane foam, a gradient foam, or the like. The FIGS. 2 a and 2 b show a second embodiment of the invention with a carrier 20 , which has a shell-like mirror housing 22 and parallel upper/lower support arms 24 , 25 extending away from said mirror housing 22 . The two support arms 24 , 25 are hollow and possess respectively a hollow space 26 , which is filled with filling material 28 . The carrier 20 incorporates on the end of the mirror housing 22 remote from the vehicle, a third hollow space 29 , which extends itself longitudinally along the rim of the mirror housing 22 , this hollow space being likewise packed with foamed fill material 28 . For the filling material 28 , preferably polyurethane foam, gradient foam, multi-component hard foam or the like can be employed. By the insertion of the foam into the follow spaces 26 and 29 , first, the stability is improved, since the foam in the hollow spaces 26 and 29 binds to the inner walls, i.e. adheres thereto. Second, by means of said insertion of foam, the vibration behavior is positively influenced, that is, the vibrations are damped. FIG. 3 illustrates a third embodiment of the invention, showing a foam carrier 30 , which incorporates a plurality of bubble shaped hollow spaces 32 and 34 . In this case, the bubble shaped hollow spaces 32 are empty, while the bubble shaped hollow spaces 34 are filled with a filling material 36 . Because of the plurality of the hollow spaces 32 , 34 , first, the weight is reduced and second, by means of the dividing walls 33 between the hollow spaces 32 , 34 , the stability is increased. By means of the filling of a portion of the hollow spaces, namely the hollow space 34 with a filling material 36 , the vibratory properties of the mirror assembly are influenced in such a way, that less vibration occurs. That is, the vibrations are damped. Additionally, in the case of the third embodiment, carrier arms 38 of metal are provided, by means of which the stability of the carrier 30 is additionally increased. FIG. 4 shows a fourth embodiment of the invention, with a carrier 40 in the form of a hollow plastic body, in which grid-type stiffening ribs 42 have been provided. The hollow plastic body 40 encapsulates a continuous hollow space 44 , which is partially filled with a gel 46 as a filling material. The partial filling of the hollow space 44 with gel 46 is illustrated by a dotted line. The grid shaped stiffening ribs 42 are made by fashioning corresponding wall thicknesses in the original plastic blanks before the blowing of these blanks in the blow-mold. By means of the grid-like stiffening ribs 42 , the stability is increased. Because of the gel 46 and the degree of the filling thereof in the hollow space 44 , the damping behavior can be specifically influenced. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention. It is intended that the present invention include such modifications and variations as come within the scope of the appended claims and their equivalents. List of Reference Numbers 2 Carrier, hollow plastic body 4 Wall of 2 6 Hollow space in 2 8 Holes for screws 10 First mirror 12 Second mirror 14 Adjustment mechanism of first mirror 16 Adjustment mechanism of second mirror 18 Filling material 20 Carrier, hollow plastic body 22 Mirror housing 24 Upper carrier arm 25 Under carrier arm 26 First and second hollow space in 24 , 25 28 Filling material 29 Hollow space in 22 30 Carrier, hollow plastic body 32 Bubble shaped hollow space in 30 , empty 34 Bubble shaped hollow space in 30 , full 36 Filling material 38 Carrier tubes 40 Carrier, hollow plastic body 42 Stiffening ribs 44 Hollow space 46 Gel, a filling material List of Reference Numbers 2 carrier, hollow plastic body 4 wall of 2 6 hollow space in 2 8 holes for screws 10 first mirror 12 second mirror 14 adjustment mechanism of first mirror 16 adjustment mechanism of second mirror 18 filling material 20 carrier, hollow plastic body 22 mirror housing 24 upper carrier arm 25 under carrier arm 26 first and second hollow space in 24 , 25 28 filling material 29 hollow space in 22 30 carrier, hollow plastic body 32 bubble shaped hollow space in 30 , empty 34 bubble shaped hollow space in 30 , full 36 filling material 38 carrier tubes 40 carrier, hollow plastic body 42 stiffening ribs 44 hollow space 46 gel, a filling material

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TECHNICAL FIELD The invention relates generally to an apparatus configured for bending metal and, more particularly, to an apparatus configured for bending sheet metal. BACKGROUND Conventional, when stone setters desire to bend sheet metal for use in securing stone panels to buildings, they manually position the sheet metal over an edge, such as an I-beam, secure it in place, such as with a C-clamp, and bend the metal as desired, typically to an angle of 90°. However, this method of bending metal tends to be laborious and inadequate to bend metal within the tolerances needed for securing stone panels to buildings. As a result, many such connectors are disposed of and costs escalate. Accordingly, a there is a need for a portable apparatus effective for consistently bending sheet metal within acceptable tolerances. SUMMARY The present invention, accordingly, provides a metal bending apparatus which has a base member and a cross member connected together by two posts extending therebetween. A spring and sleeve are slidably positioned on each post, and a wedge is secured between the sleeves, the wedge including a pointed end directed toward the base member. A stop is secured on the base member substantially directly under the pointed end of the wedge, and two blocks are positioned on the base member substantially parallel to each other and equidistant from the stop. A jack is positioned between the wedge and the cross member for urging the wedge toward the base member, and for bending a sheet of metal interposed between the wedge and the two blocks. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: FIG. 1 is a front elevation view of an apparatus embodying features of the present invention; FIG. 2 depicts a side elevation view of the apparatus of FIG. 1 ; and FIGS. 3A–3C schematically depict a method for bending sheet metal by utilizing the apparatus of FIG. 1 . DETAILED DESCRIPTION In the discussion of the FIGURES the same reference numerals will be used throughout to refer to the same or similar components. In the interest of conciseness, various other components known to the art, such as hydraulic jacks, and the like, preferred or necessary for the operation of the invention, have not been discussed in detail. It is noted that references herein to “metal” refer to metallic material, such as, by way of example, conventional carbon steel, but may include any of a number of different materials effective for implementing the invention described herein. Referring to FIG. 1 of the drawings, the reference numeral 10 generally designates an apparatus embodying features of the present invention for bending metal. The apparatus 10 preferably includes a base member 12 comprising a metal plate supported by two angle irons 14 positioned on a flat surface 15 , such as ground or a floor. As viewed in FIG. 1 , two posts 16 are secured (e.g., by welding) at their lower ends to the base member 12 , and at their upper ends to a horizontal cross member 18 that spans across the upper ends of the posts 16 . As viewed in FIGS. 1 and 2 , a vertical cross member 19 is secured (e.g., by welding) across the horizontal cross member 18 , and a handle 20 is secured (e.g., by welding) to the top of the vertical cross member 19 to facilitate portably carrying the apparatus 10 . It is noted that the cross members 18 and 19 form a T-bar, and alternatively a T-bar may be substituted therefor. A cylindrical receiver 21 is centrally secured (e.g., by welding) on a bottom side of the horizontal cross member 18 , for purposes discussed below. Sleeves 22 are slidably positioned on the posts 16 , and springs 17 are positioned on the posts 16 between the sleeves 22 and the base member 12 . A wedge 26 is secured (e.g., by welding) between the sleeves 22 , such that, as most clearly viewed in FIG. 2 , a pointed or angled end 26 a is directed downwardly toward the base member 12 . A wedge plate 27 is preferably positioned (e.g., by welding) on top of the wedge 26 . A jack 28 , such as a hydraulic jack (shown in FIG. 1 ) or the like, is positioned on the wedge plate 27 . Jacks are considered to be well-known in the industry and, therefore, will not be discussed in further detail herein, except insofar as necessary to describe the present invention. The jack 28 includes a jack body 30 positioned on the wedge plate 27 , and a piston extension portion 32 extending into the receiver portion 21 . The jack 28 also includes a conventional operational mechanism 34 for receiving a lever 36 (shown in dashed outline) configured for applying activating force to the jack 28 . Two blocks 40 and 41 are positioned and secured (e.g., by welding) on the base member 12 , and a stop 44 , such as a bolt, or the like, is secured to the base member 12 . The stop 44 is preferably centrally positioned between the two blocks 40 and 41 , substantially directly beneath the pointed end 26 a of the wedge 26 . The blocks 40 and 41 are sized, configured, and positioned on the base member 12 to facilitate bending sheet metal at a predetermined angle, as discussed in further detail below. In the operation of the metal bending apparatus 10 , as most clearly depicted in FIGS. 3A , 3 B, and 3 C, a sheet of metal 60 is inserted into the apparatus between the blocks 40 and 41 and the wedge 26 , the wedge being maintained in an elevated position by the springs 22 which urge the sleeves 22 , and hence the wedge 26 , upwardly. The lever 36 is then inserted in the operational mechanism 34 and a user applies force through the lever 36 to the jack 28 in a conventional manner to cause the piston extension portion 32 to extend outwardly from the jack body 30 , causing the wedge 26 to move downwardly and compress the springs 17 , as shown in FIG. 3B . As the wedge 26 moves downwardly, the pointed end 26 a of the wedge 26 engages the sheet metal 60 . As the wedge 26 continues to move downwardly, the sheet metal 60 deforms, bending at the point of contact with the pointed end 26 a of the wedge 26 , as shown in FIG. 3C . The wedge 26 may continue to be moved downwardly in such manner until further deformation of the sheet metal 60 is resisted by the stop 44 , at which point the operation of bending the sheet metal 60 is complete, and the sheet metal may be removed therefrom. It may be appreciated that the angle of the bend (typically about 90°) in the sheet metal 60 , deformed as described above, may be controlled by the size, configuration, and position of the blocks 40 and 41 , stop 44 , and the angle of the pointed end 26 a of the wedge 26 , all of which are design decisions, the determination of which are considered to be apparent to a skilled artisan upon a review of the present description of the invention and, therefore, will not be discussed in further detail herein. By use of the present invention, sheet metal may be consistently bent at a precise predetermined angle. The precise position of the sheet metal 60 in the apparatus 10 may also be controlled, for example, by measuring and controlling the distance of an edge of the sheet metal 60 from a block 40 or 41 . Additionally, the apparatus may be readily transported to a work site where needed. It is understood that the present invention may take many forms and embodiments. Accordingly, several variations may be made in the foregoing without departing from the spirit or the scope of the invention. For example, the stop 44 may comprise a bolt that is threaded into the base member 12 and may be adjusted by being screwed in or out, and thereby control the amount of downward movement of the wedge 26 and, hence, of the angle of bend in the sheet metal 60 . The stop may be replaced with blocks that rest on the base member 12 and may be readily replaced with blocks of differing sizes (preferably smaller than the blocks 40 and 41 ), including combinations of blocks and bolts, to thereby control the angle of bend induced in the sheet metal 60 . Depending on the stop utilized, the angle irons 14 may not be needed. Depending on the size of the blocks 40 and 41 and the angle of bend desired in the sheet metal 60 , the wedge 26 may move downwardly until it is stopped by the base member 12 , and the stop 44 may therefore not be needed. The jack 28 may be hydraulic, pneumatic, electric, mechanical, a screw mechanism, or the like, effective for urging the wedge toward the base member 12 . Depending on the type of jack utilized, the springs 17 may not be needed. While various components of the metal bending apparatus 10 are welded together, they may be secured together via screws, or like fasteners. The invention may also be used in a number of applications other than bending sheet metal. For example, the apparatus 10 may be utilized in the cutting or breaking of tile. Having thus described the present invention by reference to certain of its preferred embodiments, it is noted that the embodiments disclosed are illustrative rather than limiting in nature and that a wide range of variations, modifications, changes, and substitutions are contemplated in the foregoing disclosure and, in some instances, some features of the present invention may be employed without a corresponding use of the other features. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.

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This is a divisional application of Ser. No. 08/834,030, filed Apr. 11, 1997, now U.S. Pat. No. 6,099,945. BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to an atomic mask useful for a quantum well semiconductor laser utilizing quantum effects which take place in Bohr's atomic radius or smaller, the formation of a pattern in a ultra-micro device such as a single electron transistor, and the formation of a pattern in a recording medium such as CD-ROM. The invention also relates to a method of patterning a substrate with an atomic mask. 2. Description of the Related Art As semiconductor devices have been fabricated in smaller and smaller sizes, a metal pattern is designed to have a narrower width, and is sometimes required to have an atomic-sized width on the sub-nanometer or nanometer order. Thus, there is a need for forming a fine pattern having an atomic-sized width. To this end, there have been suggested many methods employing a scanning tunneling microscope (hereinafter, referred to simply as a “STM”) . One of such methods has been suggested in I-W. Lyo et al., Science 253, pp. 173, 1991. In the suggested method, a probe of a STM is placed close to a substrate at such a distance as a tunnel current could run therebetween with a voltage being applied across the probe and the substrate. Atoms are desorbed out of the substrate because of the field evaporation effect which takes place when a tunneling current is generated. In another method suggested by H. J. Mamin et al., “Atomic Emission from a Gold Scanning-Tunneling-Microscope Tip”, Physical Review Letters, Vol. 65, No. 19, 1990, pp. 2418-2421, there is used a probe of a STM which is coated with gold atoms by evaporation. The gold atoms are transferred from the probe to a substrate and deposit on the substrate because of the field evaporation effect. In still another method suggested by M. Baba et al., “Nanostructure Fabrication by Scanning Tunneling Microscope”, Japanese Journal of Applied Physics, Vol. 29, No. 12, 1990, pp. 2854-2857, chlorine or fluorine gas is applied onto a substrate, and etching is carried out just beneath a probe of a STM to thereby pattern the substrate. For instance, a metal gas such as WF 6 gas is flowed onto a substrate, and is decomposed just beneath a probe of a STM and deposited onto the substrate. Thus a pattern is formed on the substrate. However, the above mentioned conventional methods of forming a fine pattern by employing a STM have to repeatedly carry out the step of moving a probe to align with an atom one by one and applying a voltage across the probe and the atom. Thus, the conventional methods have a problem that it takes too much time to form a pattern. In addition, the generation of a tunneling current is greatly dependent on the shape of the probe, configuration and defects of a substrate, and contamination on a substrate etc. For instance, if there happens to exist contamination at a place where a probe is positioned, the probe may be destroyed or conditions for making a pattern are significantly varied. For the above mentioned reasons, the conventional methods would take much time for forming a lot of patterns, and might be quite unstable in forming patterns. Furthermore, a probe of a STM has to be repositioned each time when the same pattern is to be formed in other areas, resulting in a problem that it is impossible to shorten a period of time for forming a lot of patterns. SUMMARY OF THE INVENTION In view of the above mentioned problems of the conventional methods of forming a pattern by employing a STM, it is an object of the present invention to provide a method of forming an atomic-sized pattern which method is capable of forming a pattern with simple steps in a shorter period of time than conventional methods, and further capable of repeatedly forming the same patterns. It is also an object of the present invention to provide an atomic mask suitable for the above mentioned method. In one aspect, there is provided an atomic mask including a mask substrate and atoms adsorbed on the mask substrate, the atoms forming a mask pattern having a one-atomic thickness. For instance, the atoms adsorbed on the mask substrate are noble metal such as tungsten, platinum, gold and palladium. The atomic mask may further include a device for applying a current to the atomic mask, a heater for heating the atomic mask and/or a device for applying a voltage across the atomic mask and a substrate to be etched by using the atomic mask. It is preferable that the mask substrate is formed with a raised area in which the mask pattern is formed. The raised area may be formed by etching an area other than the raised area. More specifically, the raised area may be formed by the steps of depositing adatoms over a surface of the mask substrate, putting a probe of a scanning tunneling microscope close to the mask substrate, and scanning the mask substrate with the probe with a voltage being applied across the mask substrate and the probe. When the above mentioned atomic mask adsorbs adatoms which used to be deposited on a substrate to be patterned, the atomic mask may be recovered by heating in ultra-high vacuum. In another aspect, there is provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps, in sequence, of (a) depositing adatoms over a surface of a substrate to be patterned, the adatoms having low reactivity with second atoms of which the substrate is composed, and (b) putting the atomic mask close to the substrate in such a distance that the first atoms make a chemical bond with the adatoms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as an area where none of the adatoms exists. The above mentioned method is explained in brief hereinbelow with reference to FIGS. 1A to 1 F. As illustrated in FIG. 1A, there is prepared an atomic mask 4 comprising a mask substrate 1 and a mask pattern 3 composed of atoms 2 and formed on the mask substrate 1 by means of a STM (hereinafter, the atoms 2 are referred to as “mask atoms”). A desired pattern will be formed on a substrate by employing the atomic mask 4 . First, as illustrated in FIG. 1B, first atoms are adsorbed over a surface of the substrate 5 on which a desired pattern is to be formed. Herein, the first atoms are selected from atoms having low reactivity with second atoms of which the substrate 5 is composed (hence, hereinafter the first atoms are referred to as “adatoms”, and the second atoms as “substrate atoms”). Then, as illustrated in FIG. 1C, the atomic mask 4 is placed close to the substrate 5 in such a manner that the atomic mask 4 is kept parallel to the substrate 5 . When the atomic mask 4 is placed close to the substrate 5 in such a distance that the mask atoms 2 form a chemical bonding force such as Coulomb's force and electronegativity with the adatoms 6 , the adatoms 6 located nearest to the mask atoms 2 are desorbed from the substrate 5 because of the chemical bonding force generated therebetween, and are adsorbed to the mask atoms 2 patterned on the atomic mask 4 , as illustrated in FIG. 1 D. Thus, the adatoms 6 are desorbed in a pattern in line with the mask pattern 3 , as illustrated in FIG. 1F, and hence, a pattern 8 is formed on the substrate 5 . Herein, the pattern 8 has the same configuration as that of the mask pattern 3 , and is defined as an area in which none of the adatoms 6 exists. There is further provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps of (a) forming a raised area on the mask substrate, the mask pattern being to be formed within the raised area, (b) depositing adatoms over a surface of a substrate to be patterned, the adatoms having low reactivity with second atoms of which the mask substrate is composed, and (c) placing the atomic mask close to the substrate at such a distance that the first atoms form a chemical bond with the adatoms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as an area where none of the adatoms exists. The step (a) or (b) is first carried out, and the step (c) is finally carried out. The raised area may be formed by etching an area other than the raised area. Specifically, the raised area may be formed by depositing adatoms over a surface of the mask substrate, placing a probe of a scanning tunneling microscope close to the mask substrate, and scanning the mask substrate with the probe with a voltage being applied across the mask substrate and the probe. As illustrated in FIG. 5A, the mask atoms 2 patterned on the mask substrate 1 have quite a small height. Thus, an area of the mask substrate 1 other than an area 9 where the mask pattern 3 is to be formed is in advance etched, for instance, by STM, to thereby cause the area 9 to be raised above other areas, as illustrated in FIG. 5 B. The formation of the raised area 9 makes it possible to significantly enhance reactivity between the mask atoms 2 and the adatoms 6 when the atomic mask 4 is placed close to the adatoms 6 adsorbed on the substrate 5 . There is still further provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps, in sequence, of (a) depositing adatoms over a surface of a substrate to be patterned, the adatoms having low reactivity with second atoms of which the substrate is composed, (b) putting the atomic mask close to the substrate in such a distance that the first atoms form a chemical bond with the adatonms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as a first area where none of the adatoms exists, and (c) depositing third atoms having high reactivity with the adatoms and forming a bond with the second atoms, over a surface of the substrate to form a pattern in the first area and forming adatoms to be desorbed out of the substrate due to reaction with the third atoms, the pattern being defined as a second area where only the third atoms exist. In the above mentioned method, the third atoms 10 are evaporated onto a surface of the substrate 5 on which the pattern 8 has been already formed (see FIG. 1 F), as illustrated in FIG. 2 A. Herein, the third atoms 10 have high reactivity with the adatoms 6 , and also have a tendency of forming a bond with the substrate atoms 2 . By evaporation of the third atoms 10 onto a surface of the substrate 5 , the third atoms 10 are adsorbed on the substrate 5 only where the adatoms 6 do not exist, and at the same time, the adatoms 6 are desorbed from the substrate 5 because of high reactivity between the third atoms 10 and the atoms 6 , as illustrated in FIGS. 2C and 2D. As a result, as illustrated in FIG. 2B, a pattern 11 is formed of the third atoms 10 in an area where the adatoms 6 used to not exist. There is yet further provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps, in sequence, of (a) depositing adatoms over a surface of a substrate to be patterned, the adatoms being composed of etching gas atoms, the substrate being composed of second atoms, (b) placing the atomic mask close to the substrate in such a distance that the first atoms form a chemical bond with the adatoms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as an area where none of the adatoms exists, and (c) causing the adatoms and the second atoms to react with each other for forming both the adatoms and the second atoms to be desorbed out of the substrate to etch a portion of the substrate where the adatoms used to be adsorbed. In the above mentioned method, adatoms are selected from atoms of gases used for etching (thus, hereinafter atoms of gases used for etching are referred to simply as “etching gas atoms”). For instance, halogen atoms are used as adatoms. As illustrated in FIG. 3A, etching gas atoms 12 are adsorbed over a surface of the substrate 5 . Then, for instance, light is radiated over the substrate 5 , or the substrate 5 is heated to thereby make substrate atoms 13 and the etching gas atoms 12 react with each other. As a result, as illustrated in FIG. 3B, an area of the substrate 5 where the etching gas atoms 12 are adsorbed is etched, and hence a desired pattern is formed. There is still yet further provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps, in sequence, of (a) depositing adatoms over a surface of a substrate to be patterned, the adatoms having low reactivity with second atoms of which the substrate is composed, (b) placing the atomic mask close to the substrate in such a distance that the first atoms form a chemical bond with the adatoms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as an area where none of the adatoms exist, and (c) depositing etching gas atoms onto the substrate with the adatoms being used as a mask for causing the second atoms and the etching gas atoms to react with each other to form both the second atoms and the etching gas atoms desorb from the substrate, thereby a portion of the substrate where none of the adatoms exists being etched. The above mentioned method may further include the step (e) of removing the adatoms out of the substrate. The step (e) is carried out subsequently to the step (c). In the above mentioned method, as illustrated in FIGS. 3C, 3 D and 3 E, etching gas atoms 15 are adsorbed over a surface of the substrate 5 with the adatoms 14 acting as a mask. Then, the substrate atoms 13 are made to react with the etching gas atoms 15 , for instance, by heating the substrate 5 . Thus, as illustrated in FIG. 3F, an area of the substrate 5 where the adatoms 14 do not exist is etched, and a desired pattern is formed in an area where the adatoms 14 exist. There is further provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps, in sequence, of (a) depositing adatoms over a surface of a substrate to be patterned, the adatoms being composed of atoms which are readily doped into the substrate, the substrate being composed of second atoms, (b) placing the atomic mask close to the substrate in such a distance that the first atoms form a chemical bond with the adatoms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as an area where none of the adatoms exists, and (c) causing the adatoms to diffuse into the substrate. In the above mentioned method, adatoms are selected from atoms 16 having a characteristic of being doped into the substrate 5 , as illustrated in FIG. 4A (hereinafter, atoms 16 are referred to as “doping atoms”). The doping atoms 16 are diffused into the substrate 5 , for instance, by radiating a light over the substrate 5 or heating the substrate 5 . Thus, there is formed a pattern in an area of the substrate 5 where the adatoms 17 are adsorbed. There is further provided a method of patterning a substrate with an atomic mask having a mask substrate and first atoms adsorbed on the mask substrate, the first atoms forming a mask pattern having a one-atomic thickness, including the steps, in sequence, of (a) depositing adatoms over a surface of a substrate to be patterned, the adatoms having low reactivity with second atoms of which the substrate is composed, (b) placing the atomic mask close to the substrate in such a distance that the first atoms form a chemical bond with the adatoms, so that adatoms located nearest to the first atoms are desorbed out of the substrate to form a pattern on the substrate, the pattern being defined as an area where none of the adatoms exists, and (c) depositing doping atoms over the substrate with the adatoms being used as a mask for causing the doping atoms to diffuse into the substrate. In the above mentioned method, as illustrated in FIGS. 4B and 4C, doping atoms 18 are adsorbed over a surface of the substrate 5 with the adatoms 17 being used as a mask. Then, as illustrated in FIG. 4D, there is formed a pattern composed of the doping atoms 18 , for instance, by heating the substrate 5 . In all of the above mentioned methods, a current may be applied to the mask pattern during the step of placing the atomic mask close to the substrate. As illustrated in FIG. 1E, the adatoms 6 adsorbed on the substrate 5 can be surely desorbed from the substrate 5 by virtue of field effect which is produced by applying a current to the mask pattern 3 formed on the mask substrate 1 . Similarly, the atomic mask and/or the substrate may be heated during the same step. As an alternative, a voltage may be applied across the atomic mask and the substrate during the same step. The adatoms may be selected from halogen atoms such as chlorine (Cl), fluorine (F) and bromine (Br). In accordance with the present invention, it is possible to form a pattern on the sub-nanometer or nanometer order with higher accuracy and in a shorter period of time than conventional methods, and it is also possible to repeatedly form the same pattern by using the atomic mask. The above and other objects and advantageous features of the present invention will be made apparent from the following description made with reference to the accompanying drawings, in which like reference characters designate the same or similar parts throughout the drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A to 1 F are perspective or side views of an atomic mask and/or a substrate, showing respective steps of a method of patterning a substrate by employing an atomic mask, in accordance with the first embodiment of the present invention. FIGS. 2A to 2 D are perspective or side views of a substrate, showing respective steps of a method of patterning a substrate by employing an atomic mask, in accordance with the first embodiment of the present invention. FIGS. 3A to 3 F are perspective or side views of a substrate, showing respective steps of a method of patterning a substrate by employing an atomic mask, in accordance with the second embodiment of the present invention. FIGS. 4A to 4 D are perspective or side views of a substrate, showing respective steps of a method of patterning a substrate by employing an atomic mask, in accordance with the third embodiment of the present invention. FIGS. 5A and 5B are side views of an atomic mask, showing respective steps of a method of patterning a substrate by employing an atomic mask, in accordance with the fourth embodiment of the present invention. FIG. 6 is a side view of an atomic mask, illustrating a method of fabricating an atomic mask. FIGS. 7A to 7 C are side views illustrating variations of the first to fourth embodiments of the present invention. FIG. 8 is a side view of an atomic mask, illustrating another method of fabricating an atomic mask. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments in accordance with the present invention will be explained hereinbelow with reference to drawings. The first embodiment is explained hereinbelow with reference to FIGS. 6, 1 A to 1 F and 2 A to 2 D. FIG. 6 illustrates a method of fabricating an atomic mask to be used in the first embodiment. The atomic mask is fabricated employing a system for flowing various gases and an ultra-high vacuum STM including an evaporation source. As illustrated in FIG. 6, there are used a mask substrate 1 and mask atoms 2 of which a mask pattern is composed. The mask substrate 1 is composed of Si or GaAs, and the mask atoms 2 are tungsten (W) atoms. After the mask substrate 1 is placed in a STM, metal gas 19 for forming a pattern is introduced into an evacuated container (not illustrated). In the instant embodiment, since the mask atoms 2 are tungsten atoms, there is used WF 6 gas as the metal gas 19 . Then, a STM probe 20 is placed close to a surface of the mask substrate 1 , and subsequently an electric power source 21 applies a voltage across the probe 20 and the mask substrate 1 . Herein, the applied voltage is determined so that the voltage corresponds to an energy by which atoms of the metal gas 19 are dissociated from the mask substrate 1 . Specifically, the applied voltage is about 5 V. When the metal gas atoms are dissociated, volatile gas atoms or fluorine atoms 22 are scattered, and hence only tungsten atoms 2 are deposited on the mask substrate 1 as the mask atoms. Then, the probe 20 is moved along a desired pattern to thereby form a mask pattern 3 on the mask substrate 1 . Thus, there is completed the atomic mask 4 including the mask pattern 3 composed of the atoms 2 and having a one-atomic thickness. As explained hereinbelow, an aluminum wiring is formed on the substrate 5 by employing the above mentioned atomic mask 4 in the instant embodiment. As illustrated in FIG. 1A, the atomic mask 4 comprises the mask substrate composed of Si or Au, and the mask pattern 3 composed of the mask atoms 2 adsorbed on the mask substrate 1 in a pattern. The atoms 2 are tungsten atoms having relatively high melting point. Dangling bonds of the mask pattern 3 are terminated in order to prevent impurities such as oxygen in the atmosphere from adhering thereto. The formation of a pattern 8 on a silicon substrate 5 is conducted in ultra-high vacuum, specifically at a vacuum of 4×10 −10 Torr or less, because the pattern formation is greatly influenced by soil or impurity, even if such soil or impurity consists of a few atoms. First, as illustrated in FIG. 1B, chlorine atoms 6 as adatoms are adsorbed over a surface of the silicon substrate 5 on which an aluminum wiring is intended to form. In order that the chlorine atoms 6 are uniformly distributed over the silicon substrate 5 , chlorine gas of 8×10 −10 Torr is applied onto a surface of the silicon substrate 5 with the silicon substrate 5 being kept at about 450° C. Thus, the chlorine gas atoms 6 as adatoms are adsorbed on a surface of the silicon substrate 5 . Then, the atomic mask 4 is heated up to about 800° C. in ultra-high vacuum to desorb impurity atoms from the tungsten atoms 2 to which the impurity atoms have been adhered. Thus, the tungsten atoms 2 are now in an activated state and hence are likely to react with other atoms. Then, as illustrated in FIG. 1C, the atomic mask 4 is placed close to the silicon substrate 5 with the atomic mask 4 being kept in parallel alignment to the silicon substrate 5 . When the mask pattern 3 formed on the mask substrate 1 approaches the adatoms 6 by a distance corresponding to diameters of a few atoms, specifically, a distance on the sub-nanometer or nanometer order, the chlorine atoms or adatoms 6 are influenced by a potential of the tungsten atoms 2 patterned on the mask substrate 1 , and are desorbed from the silicon substrate 5 , as illustrated in FIG. 1 D. Thus, the chlorine atoms 6 are adsorbed to the tungsten atoms 2 . In order to facilitate the adsorption of the chlorine atoms 6 to the tungsten atoms 2 , a current 7 may be applied to the mask pattern 3 of the atomic mask 4 . The current 7 produces a field effect, which facilitates, the desorption and adsorption of the adatoms 6 . As a result, the chlorine atoms 6 are desorbed from the silicon substrate 5 in accordance with the mask pattern 3 , and accordingly there is formed a pattern 8 on the silicon substrate 5 , which pattern 8 is the same in configuration as the mask pattern 3 . As is obvious in FIG. 1F, the pattern 8 is defined as an area where the adatoms 6 do not exist. Then, as illustrated in FIG. 2A, aluminum atoms 10 are evaporated onto a surface of the silicon substrate 5 on which the adatoms 6 form the pattern 8 . Since the aluminum atoms 10 have high reactivity with the chlorine atoms 6 and have a characteristic of readily depositing on the silicon substrate 5 , the aluminum atoms 10 are adsorbed onto the silicon substrate 5 in an area where the adatoms or chlorine atoms 6 are not adsorbed, as illustrated in FIG. 2 C. In addition, as illustrated in FIG. 2D, the chlorine atoms 6 adsorbed on the silicon substrate 5 react with the aluminum atoms 10 to thereby desorb from the silicon substrate 5 . As a result, the aluminum atoms 10 adsorbed onto the silicon substrate 5 form a pattern 11 . That is, the chlorine atoms 6 adsorbed on the silicon substrate 5 act as if they are a photoresist in photolithography for aluminum evaporation. In the instant embodiment, the deposition of the aluminum atoms 10 and the desorption of the chlorine atoms 6 simultaneously take place. The used atomic mask 4 which adsorbs the chlorine atoms 6 thereto as illustrated in FIG. 1D can be recovered for reuse by heating the used atomic mask 4 to thereby desorb the chlorine atoms 6 from the tungsten atoms 2 . As the mask atoms 2 of which the mask pattern 3 is composed, there may be used metal atoms having a relatively large mass, such as noble metal atoms. Specifically, platinum (Pt), gold (Au) and palladium (Pd) atoms as well as tungsten atoms may be used as the mask atoms 2 . It is preferable to employ halogen atoms as the adatoms 6 , such as chlorine (Cl), fluorine (F) and bromine (Br), because halogen atoms have high reactivity with other atoms, and hence the desorption of the adatoms 6 can be facilitated when the atomic mask 4 is placed close to the adatoms 6 adsorbed on the silicon substrate 5 . As illustrated in FIGS. 7A and 7B, the atomic mask 4 and/or the silicon substrate 5 may be heated with a heater 23 when the atomic mask 4 is placed close to the silicon substrate 5 . As an alternative, an electric power source 21 may be employed to apply a voltage across the atomic mask 4 and the silicon substrate 5 to thereby generate an electric field while the atomic mask 4 is being put close to the silicon substrate 5 . The field effect brought by the electric field would facilitate the desorption of the adatoms 6 from the silicon substrate 5 . When the atomic mask and/or the silicon substrate 5 is heated as illustrated in FIG. 7A or when a voltage is applied across the atomic mask 4 and the silicon substrate 5 as illustrated in FIG. 7B, as well as when the current 7 is applied to the atomic mask 4 as illustrated in FIG. 1E, there may be used gas atoms as the adatoms 6 , which have a relatively small mass. For instance, hydrogen, oxygen, helium and argon gases may be used to provide the adatoms 6 . In accordance with the instant embodiment, if the atomic mask 4 is once formed, it is possible to repeatedly form the same patterns by employing the atomic mask 4 . Accordingly, the instant embodiment significantly shortens a period of time for forming a pattern on a substrate and forms a pattern more readily in contrast to conventional methods where a STM probe has to be moved atom by atom and a voltage has to be repeatedly applied across the STM probe and a substrate. The second embodiment in accordance with the present invention is explained hereinbelow with reference to FIGS. 3A to 3 F. The second embodiment has the same steps until the chlorine atoms 6 make the pattern 8 on the silicon substrate 5 . Only subsequent steps are different between the first and second embodiments. Hence, there are explained hereinbelow only steps different from the first embodiment. After the chlorine atoms 12 have formed the pattern 8 on the silicon substrate 5 as illustrated in FIG. 3A, the silicon substrate 5 is heated up to about 650 degrees centigrade. Herein, the chlorine atoms 12 have a characteristic of etching silicon. Hence, an etching reaction takes place by heating the silicon substrate 5 between the chlorine atoms 12 and silicon atoms 13 at a surface of the silicon substrate 5 . As a result, as illustrated in FIG. 3B, the silicon atoms 13 located just beneath the chlorine atoms 12 are etched out, thereby there is formed a pattern on a surface of the silicon substrate 5 . The pattern is defined with a recessed or etched portion at which the adatoms 12 used to exist, and a raised or non-etched portion at which the adatoms 12 does not exist. As illustrated in FIGS. 3C and 3D, non-reactive gas atoms 14 such as nitrogen atoms may be adsorbed as the adatoms on a surface of the silicon substrate 5 . Then, fluorine gas is applied to a surface of the silicon substrate 5 . The fluorine gas atoms 15 are adsorbed on the silicon substrate 5 in an area where the adatoms 14 are not adsorbed, because the adatoms 14 act as a mask. Since fluorine has a characteristic of etching silicon, the area of the substrate 5 where the adatoms 14 are not adsorbed is etched, as illustrated in FIG. 3 E. Thus, there is formed a pattern on the silicon substrate. The pattern is defined with a recessed or etched portion at which the adatoms 14 used not to exist, and a raised or non-etched portion at which the adatoms 14 exist. The adatoms 14 having acted as an etching mask may be removed by heating treatment, as illustrated in FIG. 3 F. It should be noted that the pattern as explained with reference to FIG. 3B is opposite to the pattern as explained with reference to FIG. 3F with respect to the raised and recessed portions both of which the patterns are formed. The third embodiment in accordance with the present invention is explained hereinbelow with reference to FIGS. 4A to 4 D. The third embodiment has the same steps until the adatoms form the pattern 8 on the silicon substrate 5 . Only subsequent steps are different between the first and third embodiments. Hence, there are explained hereinbelow only steps different from the first embodiment. In the third embodiment, the adatom is selected from atoms which are readily doped into the silicon substrate 5 , such as boron and nitrogen. Hence, the pattern 8 formed on the silicon substrate is composed of boron atoms 16 as the adatoms in the instant embodiment. After the pattern 8 has been formed on the silicon substrate 5 , the substrate 5 is heated for about 2 hours at 250 degrees centigrade. As a result, as illustrated in FIG. 4A, the boron atoms 16 are diffused into the silicon substrate 5 , thereby the doping atoms 16 forming a pattern in the silicon substrate 5 . Since the instant embodiment makes it possible to dope at atomic level, a steep profile may be accomplished in doping. As an alternative, as illustrated in FIG. 4B, non-reactive gas atoms 17 may be adsorbed on the silicon substrate 5 as the adatoms. Nitrogen atoms 18 as the doping atoms are applied to the silicon substrate 5 , so that the nitrogen atoms 18 are adsorbed on the silicon substrate 5 in an area where the non-reactive gas atoms 17 are not adsorbed. Then, the silicon substrate 5 is heated to thereby diffuse the nitrogen atoms 18 into the silicon substrate 5 with the non-reactive gas atoms 17 being used as a mask, as illustrated in FIG. 4 C. Thus, there is formed a pattern as illustrated in FIG. 4 D. The thus formed pattern is opposite to the previously mentioned pattern in terms of a diffusion region. That is, an area where the adatoms 16 exist is doped in FIG. 4A, whereas an area where the adatoms 17 do not exist is doped in FIG. 4 B. The non-reactive gas atoms or adatoms 17 having acted as a mask in doping are desorbed while the silicon substrate 5 is heated for doping, as illustrated in FIG. 4 D. In accordance with the above mentioned second and third embodiments, it is possible to shorten a period of time for forming a pattern on a substrate and form a pattern more readily in contrast to conventional methods, similarly to the first embodiment. Hereinbelow is explained the fourth embodiment with reference to FIGS. 5A, 5 B and 8 . In the instant embodiment, an atomic mask is improved in configuration. When the atomic mask 4 is placed close to the adatoms 6 adsorbed on the silicon substrate 5 , a chemical bonding force to be generated between the mask atoms and the adatoms 6 is deteriorated by other atoms. Thus, in order to reduce the deterioration of the chemical bonding force, an area of the mask substrate 1 other than an area where the mask pattern 3 is to be formed is etched by means of a STM prior to the formation of the mask pattern 3 . Specifically, as illustrated in FIG. 8, fluorine atoms 24 are adsorbed onto a surface of the silicon substrate 1 . Then, a probe 20 of a STM is placed close to an area of the silicon substrate 1 which is intended to be etched, and thereafter a voltage of about 3 V is applied across the probe 20 and the silicon substrate 1 through an electric power source 21 . As a result, an area where the probe 20 scans is etched out. Subsequently, for instance, the first embodiment is carried out to thereby form the mask pattern 3 of the tungsten atoms 2 . In accordance with the fourth embodiment, an area 9 where the mask pattern 3 is to be formed is raised relative to other areas of the mask substrate 1 , as illustrated in FIG. 5 B. Hence, when the atomic mask 4 is placed close to the silicon substrate 5 , silicon atoms located in an area other than the area 9 exert less influence on the adatoms 6 adsorbed on the silicon substrate 5 , resulting in significant enhancement in reactivity between the adatoms 6 and the tungsten atoms 2 . While the present invention has been described in connection with certain preferred embodiments, it is to be understood that the subject matter encompassed by way of the present invention is not to be limited to those specific embodiments. On the contrary, it is intended for the subject matter of the invention to include all alternatives, modifications and equivalents as can be included within the spirit and scope of the following claims. The entire disclosure of Japanese Patent Application No. 8-89738 filed on Apr. 11, 1996 including specification, claims, drawings and summary is incorporated herein by reference in its entirety.

4y

BACKGROUND OF THE INVENTION This invention relates to a portable separator device, and particularly one for separating panel units from one another. Sections of insulated glass are typically formed by the stack process, wherein sheets of glass are laid up, with alternate pairs of glass sheets being separated by marginal strips. When a pair of sheets and the interposed stripping is sealed around the edges, a section of insulated glass is produced. Such a section is herein called a panel. In the stack process, rather than trying to seal the edges of the inchoate panels individually, it is more economical to do it all at once. Thus a plastic sealant is painted or sprayed onto the entire surfaces of the four sides of the stack to completely cover them. When the sealant dries, the resulting film not only provides the proper seal at the edges of the panels, but inadvertently bonds the panels to one another at their parting planes. At present, the panels are separated by manually running a razor around the stack at such places. This is a time-consuming and expensive operation. I have overcome this problem by providing a portable separating device which can be taken from stack to stack to do its job. At a desired stack, it is simply placed onto and supported by the top of the stack. It has opposed, vertically staggered stack-engaging pads so located that when the device is actuated, they are moved relatively toward one another to grip the stack and apply a shearing force to the top panel to shift it relative to the remainder of the stack an extent to rupture the plastic film at the parting plane between the top panel and the next lowermost one. The grip of the device is then released and it is lifted off. Then, the top panel is removed, and the device applied to the next lowest panel, and the separating step repeated. More specifically, I have provided a portable panel separator having a beam of a length to horizontally span a stack, and equipped with a pair of feet to support it on the top of the stack. At one end, the beam has a stack-engaging pad which is so vertically located relative to the supporting surfaces of the feet, that the feet dispose the pad in alignment with the associated edge of the top panel, but above the lower panels. At its other end, the beam has an actuator, such as a piston and cylinder unit. The piston rod carries a second stack-engaging pad which is so located relative to the supporting surfaces of the feet, that the feet dispose the pad next to the side of the stack at a level below that of the top panel. When the cylinder unit is actuated the second pad is forced horizontally against the panels below the top one. This pulls the first pad against the associated edge of the top panel, so that the pads apply a shearing action to the stack. Since the resistance to movement of the top panel is less than that of the next lower panel, the entire device, except for the piston rod and its pad, shifts horizontally relative to the stack, carrying the top panel with it. The amount of movement need only be sufficient to rupture the seal between the top two panels. The device is then lifted, the top panel removed, the device replaced and the operation repeated. The main object of the present invention is to provide a device facilitating separation of a stack of panels which are secured to one another by a film or layer at their edges. A more specific object is to provide such a device which is portable, and particularly one that is readily adjustable for different thicknesses and sizes of panels. The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. The invention, however, both as to organization and method of operation, together with further advantages and objects thereof may best be understood by reference to the following description, taken in connection with the following drawings, wherein like reference characters refer to like elements. FIG. 1 is a schematic elevational view of my separator device applied to a stack of panels; FIG. 2 is a view like FIG. 1, but showing the device having been actuated to shift the top panel; FIG. 3 is a vertical elevational view of a device embodying the concepts of the present invention, showing the same mounted on a stack of panels to be separated; FIG. 4 is a plan view of the separator device; and FIG. 5 is a sectional view taken along line 5--5 of FIG. 4. DESCRIPTION FIGS. 1 and 2 are schematic drawings in which, for convenience in illustration, their dimensions are distorted so that important relationships, functions, and movements can more readily be understood or seen. FIG. 1 shows a device 11 of my invention having been placed on and supported by a stack 13 of insulated glass panels. The stack is shown as comprising only six panels, identified as 13a-13f. Typically, there would be many more. The lay up method is conventional, and comprises laying up sheets of glass, with alternate pairs being separated at their margins by separating material in the form of strips. FIG. 1 identifies the sheets 13f' and 13f" of panel 13f, and the strips 14 of such panel. The laid up stack then has a plastic sealant applied to all four of its sides to completely cover them. When the sealant dries, it provides a plastic coat or film 17, which not only properly seals the edges of the various panels, but also inadvertently secures or bonds the panels to one another at their parting planes. It is this bond that needs to be ruptured or broken. My separator device is to perform this function. It comprises a beam 20 having feet 21 and 23 resting on the stack, and specifically on the top panel 13a, whereby the device is supported by the stack. At its right end, as the parts are shown, the device has a pad or stop 27. The beam plus the pad may be considered as a J-shaped member. The feet function as depth guides to automatically locate the pad opposite the associated edge of the top panel 13a, but above the edges of the lower panels. At its left end, the beam has a bracket 29 supporting an actuator, which is shown in the form of a pneumatic piston and cylinder unit 31. The unit has a piston 33 whose piston rod 35 carries a pad 37. The latter is vertically located by the feet 21 and 23 at a level below that of the top panel 13a, preferably horizontally opposite the associated edge of the next lower panel 13b. Now, if the piston and cylinder unit is actuated, the pad 37 will apply a horizontal thrust against the side of the stack, which is resisted by the engagement of the pad 27 with the top panel. This creates a shearing action. The resistance to movement of the top panel is less than that of panel 13b engaged by the pad 37. Therefore, the pad 37 and the piston rod remain stationary, but the reactive force causes the entire separator device, except for the rod and the pad, to be shifted to the left as shown in FIG. 2, carrying the top panel 13a with it. This ruptures the plastic film 17 at the parting plane between the top panel 13a and the next lowest panel 13b, without harming the edge bond at the edges of either panel. Now the clamping pressure is relaxed, the device lifted, the top panel pulled off the stack, the device replaced, and the operation repeated on the remaining panels in turn. FIGS. 3-5 show a device embodying my invention, wherein the proportions are more realistic than in FIGS. 1 and 2. The beam 20 is shown as comprising a spring steel bar on which the depth guide feet 21 and 23 are mounted, in a manner to be presently explained. At the left hand end of the bar, as the parts are shown in FIGS. 3 and 4, the bracket 29 has a through bore, receiving the left hand end of the bar 20, the bracket being secured to the bar by screws 41. The pneumatic piston and cylinder unit 31 is hung by bolts 43 from the bracket 29. The piston and cylinder unit has its piston rod 35 projecting therefrom and projecting into and secured to the pusher bar 37. The pusher bar is provided with a plastic face pad 37a, which has fixed pins 51 fitting in holes provided in the pusher bar and held in place by set screws. The depth guide foot 21 has a bracket 21a formed with a through bore to receive the bar 20, the foot being secured to the bar by a screw 71 (FIG. 4). From the lateral ends of the bracket 21a are secured a pair of depth guide plates 21b and 21c which are secured to the bracket 21a by bolts 21d. The two depth guide plates are notched at their lower ends to provide edges 21f for contact with the upper panel 13a, and edges 21g for disposition next to the left side of the stack, as the parts are shown in FIG. 3. The lower edges 21h of the plates slidably rest on the upper faces of the face pad and the pusher bar. The importance of this will be evident presently. The other depth guide foot 23 has a bracket 23a from the lateral end of which depend a pair of depth guide plates 23b and 23c secured to the bracket by bolts 23d. The depth guide plates have lower edges 23e for contact with the upper surface of the stack, and more specifically the top panel. The bar 20 slidably extends through the bracket 23a but is releasably held in a desired position of adjustment along the bar by an adjustable tail block 81. There are plural stop plates 83 formed with rectangular holes to receive the bar with sufficient looseness that the stop plates can assume the positions in FIG. 4 inclined to the vertical, with their interior edges biting into the bar 20. The tail block has a spring tongue 87 secured at its left hand end to releasably fit onto an upwardly projecting pin 89 on the bracket 23a. A stop or pusher bar 91 is accommodated within notches 23f of the plates 23b and 23c and is pivotally connected to the tail block by a single bolt 93. The bar carries the pad 27 which is secured to the backup bar by a pair of pins 97 (compare FIGS. 3 and 4). The notches 23f provide downwardly facing edges slidably resting on the upper face of the plastic face pad 27. It is important to note that the depth guide plates 23c and 23d will locate the lower face of the plastic face pad just above the plane separating the uppermost panel 13a from the next lower panel 13b, while the plates 21b and 21c dispose the pad 37a below the top panel 13a and opposite the associated edges of panels 13b-13d. In operation, when the pneumatic piston and cylinder unit is actuated, a thrust force is applied by the piston and cylinder unit through the pad 37a to the stack 13. This thrust force transmitted by the bar 20 to the face pad 27, pulls the latter against the upper panel 13a. Since the left hand face pad 37 meets more resistance to moving the panels it contacts than does face pad 27 to moving the uppermost panel, the entire separator device, except for the face pad 37a and pusher bar 37 and piston rod 35, shift to the left, carrying panel 13a with it, to rupture the film bond between the uppermost panel and the next lower one. Note that when the device moves to the left, the depth guide plates simply slide on the bar 37 and pad 37a. Now the supply of air under pressure is terminated to release the grip of the device on the stack. The device can simply be lifted off, the panel 13a removed and the device replaced onto the next uppermost panel 13b and the operation repeated to separate it from the next lowermost panel. If it is desired to shift the foot 23 along the bar 20 to adjust the device to wider stacks, the workman manually moves the set of stop plates 83 to a more upright position, against the resistance of a conventional bent wire spring (not shown), to release the grip of the stop plates 83 on the bar 20. With stacks of small sized panels, it is possible to locate the separator device 11 approximately centrally of the panels, whereby the uppermost panel to be separated will be shifted to the left breaking the film bonds at the four sides of the stack and maintaining the upper panel in essentially a rectilinear line of movement. However, with larger panels, particularly longer ones, I have discovered it is better to locate the separator device near one end of the stack of panels and run it through its sequence of operation. This time, however, when the piston and cylinder unit is actuated, the end of the uppermost panel at which the separator device is located will be shifted the extent of travel of the piston and cylinder unit 31, whereas the opposite end is shifted oppositely, so that the uppermost panel is now askew with reference to the lowermost panels, to break the bond between the panels. In order to accommodate this movement, the bar 91 as previously mentioned is pivoted at 93 to enable the bar and the pad to turn to maintain flush contact with the uppermost panel even though the uppermost panel is askew to the lower panels in the stack. While my device may entirely separate an upper panel from the next lower one, with some panel sizes, the separation may be less than complete. However, the workman need only give the upper panel a final twist to complete the separation. Or, two devices could be provided, and located adjacent the opposite ends of the stack, to effect a complete separation. As is evident from FIG. 3, the bins which mount the face pads to their bars are offset from the horizontal midplanes of the pads. This means that the bolts can be removed, the face pads inverted and resecured, whereby to locate the pads lower faces at a lower level than was previously the case. This means that with a simple adjustment, the unit shown is adaptable to operate on panels of two thicknesses rather than just one. To adapt the device to other thicknesses of panels, the guide feet can be replaced by feet having different sized notches. Lifting of the spring tongue 87 permits separation of the tail block 81 from the bracket 23a. This enables the pad 27 to be inverted without removing the pad 91 from the tail block. Preferably the depth guide plates are formed of a plastic material for easier contact with the glass panels. Instead of mounting the stop plates 83 so that they engage the upper and lower edges of the beam 20, the plates may be arranged to project horizontally and thus engage the sides of the beam, so that the upper and lower edges are not roughened by the action of the stop plates. The beam may be of I-shape in cross section, with the stop plates engaging the recessed portions of the sides of the beam. The source of air under pressure has not been shown. It may be that source typically available in shop surroundings, which will be connected by a hose to a foot pedal control (not shown) for controlling the supply of air to the piston and cylinder unit.

4y

BACKGROUND OF THE INVENTION This invention relates in general to foam products and more specifically, to methods of improving the flame resistance of foam products. Foamed plastics have long been used in a variety of thermal insulation applications. Some, such as polystyrene, melt at moderately elevated temperatures so are used only at approximately room temperature or below, such as in insulation of coolers or refrigerators. Others, such as polyimides, have excellent resistance to high temperatures and may be used in high temperature applications. In cases where the insulation must resist direct exposure to flame, the insulation generally required cover layers of metal, asbestos or the like which are heavy and present other problems. Metal oxides in the sub-micron size range are known to have excellent thermal insulating capabilities. However, because of the small particle size and the fact that particles of oxides such as aluminum oxide and silicon dioxide take strong particle electrical charges, these materials have been difficult to handle and employ in insulation. Generally, they have only been used when enclosed, typically in a reservoir-type enclosure. Furthermore, the oxides are rather transparent in the infra-red portion of the spectrum, compromising the otherwise good thermal insulating properties where large temperature differences exist across the particle mass. Thus, there is a continuing need for improved insulation materials, resistant to high temperatures and flames. SUMMARY OF THE INVENTION The above-noted problems, and others, are overcome by preparing insulation by a method which basically comprises forming a stable suspension or gel of a suitable very finely divided metal oxide in a liquid, placing a suitable open-cell foam shape in the gel until all of the interstices are filled with the gel, then removing the shape and drying it to remove the liquid, leaving the metal oxide uniformly dispersed throughout the foam. The suspension or gel has the property of preventing settling of the particles while remaining capable of easily flowing throughout the foam cells and wetting the cell walls. Any suitable liquid may be used in forming the gel. Water is generally preferred for convenience, ready availability and low cost. The particles may be any suitable metal oxide particles having the desired insulating properties. Typical metal oxides include aluminum oxide, silicon dioxide, titanium dioxide and mixtures thereof. For optimum results we prefer a mixture of aluminum oxide and silicon dioxide, at a ratio of about 1:6 by weight. While any suitable metal oxide particle size may be used, we prefer particles in the 10 to 40 nanometer diameter range. One particularly desirable metal particle composition is marketed by the Degussa Corporation, Allendale, N.J. under the Aerosil COK84 designation. This material consists of 82 to 86 wt. % silicon dioxide and 14 to 18 wt % aluminum oxide having average particle sizes in the 10 to 80 nanometer range. I prefer to include a small amount of very finely divided titanium dioxide in the gel. The titanium dioxide does not adversely affect the suspension properties of the gel. The titanium dioxide serves to opacify the foam/oxide product to infra-red radiation, reducing the amount of heat transferred across the insulation. Preferably, the particles size of the titanium dioxide is in the 10 to 80 nanometer range. Is preferable to use from about 0.1 to 10.0 weight percent titanium dioxide in the metal oxide mixture, based on the total weight of the other oxides in the mix. Any suitable open-cell, high temperature resistant, synthetic resin foam may be treated by this method. Such foams may typically be formed from polyimides, polyurethanes, and other polymer foams. I prefer polyimides due to their particularly desirable high temperature and flame resistance and because they do not emit significant quantities of toxic gases when exposed to flame. The gel may be introduced into the foam cells in any suitable manner. I have found it most convenient to simply gently submerge the foam in the gel for a period sufficient to allow the gel to fully fill the cells concurrent with hand rolling of the foam to alternately compress and release the foam. The foam is then removed from the gel passed through pinch rolls to leave in an exact predetermined amount of gel, and thereby the desired amount of metal oxides. The filled wet foam is then dried, such as by heating in a conventional thermal oven. The foam insulation is then ready for use or any suitable post-treatment. BRIEF DESCRIPTION OF THE DRAWING Details of the invention, and of certain preferred embodiments thereof, will be further understood upon reference to the drawing, wherein: The FIGURE shows a schematic flow diagram of a preferred series of steps making up the insulation manufacturing method. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS As seen in the Figure, the first step is to pour the finely divided metal oxides from a container 10 into a suitable liquid 12, such as water, in a container 14 using a conventional mixer 16 until a uniform suspension or gel is formed. A sheet of open-cell foam 18 is then submerged in the liquid 12 until all foam interstices are filled with the gel, generally indicated by cessation of air bubbles emitting from the foam. A simple hand roller moved across the foam in the liquid is effective in reducing the time necessary to complete filling of the cells. While other open-cell foams may be used, as discussed above, we prefer polyimides. Typical polyimide foams include the open-celled foams disclosed by Gagliani et al in U.S. Pat. Nos. 4,426,463, 4,439,381 and 4,506,038, by Long et al in U.S. Pat. No. 4,518,717 and by Shulman et al in U.S. Pat. No. 4,467,597. The foam may incorporate any suitable additives, such as surfactants to improve uniformity of cell structure, blowing agents, fillers, reinforcements, or other agents as desired. Typical surfactants include BRIJ-78 from ICI Corp., FSN and Zonyl from E. I. DuPont de Nemours & Co., L5302 and L5430 from Union Carbide Corp., 190 and 193 from Dow Corning Corp. and FC 430 from Minnesota Mining and Manufacturing Co. While any suitable concentration may be used, generally from about 0.5 to 2 wt % (based on the weight of the liquid foam precursor) is preferred. Typical fillers include glass microballoons, fiber of glass, graphite, Kevlar aramids, ceramics or the like, fluorocarbon powders, etc. In order to adjust the quantity of gel, and resulting metal oxides, in the foam, the foam may then be run through the nip between spaced rollers 20. The spacing between the rollers is adjusted to leave the selected amount of gel in the foam. Excess gel is allowed to fall back into container 14. Of course, if the maximum amount of gel (and resulting metal oxide) in the foam is desired, this step may be eliminated. While the rollers as shown are preferred for ease and convenience, other methods may be used to squeeze out excess gel, such as compression between two opposing platens. Next, the foam is dried in an oven 22 leaving the finely divided metal oxides uniformly dispersed throughout the foam cells. Any suitable method may be used to dry the foam, including simply air drying at room temperature. A conventional circulating air thermal oven is preferred for speed and simplicity. Upon removal from the oven, the sheet of metal oxide impregnated foam 18 is ready for use in high-temperature insulation applications. However, for many such applications, further post-treatment of the foam may be beneficial. Often, foam of higher density and greater strength may be desired with at least some of the open cells closed. As seen in the next step, the foam 18 may be squeezed to a lesser thickness between a pair of opposed compression tools 24. The assembly of tools and foam is then placed in a suitable oven 26 and heated to the stabilization temperature of the foam, at which temperature the foam is set in the new shape. Any suitable oven may be used, such as a conventional circulating air thermal oven. In the case of polyimide foam, foam density can be increased as much as 1500 percent without significantly degrading its thermal resistance. The densification step improves flame resistance and rigidity. Also, densification tends to collapse the cells in the foam, effectively trapping the metallic oxides in the foam. The dimensions of the final foam shape are stabilized by the densification step so that the final product closely fits the dimensions of the tooling. This permits the production of highly accurate parts using inexpensive tooling. If desired, compression tools 24 may have any of a variety of suitable shapes. For example, one could be concave and the other correspondingly convex, producing a final foam product having a curved shape. Or, the face of one or both tools 24 could be configured to produce a corresponding surface pattern on the final foam sheet. Complex shapes, such as distorted tubes can be made by laying up the assembly components on a mold surface prior to full drying in oven 22, then heating to dry and set the foam to fit the mold. Alternatively, a plurality of thin pliable dried sheets can be assembled on a curved mold in place of compression tools 24 and heated and compressed to produce a complex final stabilized foam product. Face sheets or other articles may be bonded to foam 18 during the densification and stabilization step. For example a sheet of material, such as a fiberglass fabric or the like having a heat activated adhesive on one side could be placed on foam 18 with the adhesive contacting the foam just prior to placing the foam between compression tools 24. The final product, then, is a sheet of foam insulation having an accurate shape and outstanding resistance to high temperatures and direct flame contact. The products may be further adhesively bonded together into thicker or more complex products. The following Examples provide further details of certain preferred embodiments of the method of my invention. Parts and percentages are by weight unless otherwise indicated. EXAMPLE I About 150 grams of Monsanto 2601 Skybond polyimide prepolymer is mixed with about 2 wt % Dow-Corning 193 surfactant. The solution is rolled onto glass plates and dried with warm air at about 150° F. The dried coating is scraped off the glass and ground to a powder in a standard kitchen blender. The powder is then spread onto Teflon fluorocarbon coated glass fabric and foamed in a circulating air oven heated to about 350° F. for about 45 minutes. After foaming, the temperature is increased to about 575° F. for about 1 hour to cure the polyimide. The resulting flexible open-cell foam is trimmed to a thickness of just over 0.5 inch. The foam is immersed in a pan containing a soupy gel made by mixing about 0.5 grams of Aerosil COK84 in 300 ml. water. About 15 grams of P-25 powdered titanium dioxide from Degussa is then mixed into the gel. The foam is gently rolled with a hand roller while in the gel until it is loaded with gel. The foam is then removed from the gel and passed through pinch rolls set about 3/16 inch apart which removes much of the trapped gel. The foam is then dried for about 1 hour at about 250° F. in a conventional thermal oven. The product is a foam which is highly resistant to direct flame when placed over a bunsen burner, when compared with a similar piece of untreated foam. EXAMPLE II A sheet of the foam made by the method of Example I is placed between two flat, mold-release coated, platens and compressed to a thickness of about 0.25 inch. The assembly of platen and foam is placed in a thermal oven and heated to about 550° F. for about 30 minutes. The assembly is removed from the oven and cooled to room temperature. The foam is removed from the platens and found to have an increased resistance to flame when compared to the product of Example I, to have greater rigidity and to be dimensionally stable. EXAMPLE III The method of Example II is repeated except that the two platens have corresponding, parallel, convex and concave shapes, A face sheet is prepared by dusting a sheet of fiberglass fabric with Skybond prepolymer, then placing the foam against the dusted surface. This laminate is then placed between the curved platens, which are brought together to a spacing of about 0.2 inch. The assembly is placed in a thermal oven and heated to about 550° F. for about 30 minutes. Upon removal from the oven, cooling to room temperature and removal from the platens, a dimensionally stable foam sheet having surfaces corresponding to the platen surface and having the face sheet well bonded to one surface results. EXAMPLE IV A gel is prepared as in Example I above. Polyimide foam 1-inch thick and 12-inches square manufactured by Imitech Division of Ethyl Corp. is immersed, removed, and squeezed out as described in Example I. The sample is thoroughly dried and then placed between two aluminum tooling plates having Teflon coated fiberglass as mold releases. The two plates reduce the thickness of the foam to about 1/4-inch. The assembly is then heated to about 450° F. for about 1 hour. The resulting product accurately matches the tooling, has reduced cell size, increased density, and has greatly improved flame resistance when exposed to a bunsen burner flame, as compared to the untreated foam. Certain specific materials, amounts and conditions were specified in the above descriptions of preferred embodiments. These may be varied, where suitable, with similar results. Other variations, applications and ramifications of this invention will occur to those skilled in the art upon reading to this application. Those are intended to be included within the scope of this invention, as defined in the appended claims.

4y

[0001] This application claims the benefit of U.S. Provisional Application No. 61/113,103, filed Nov. 10, 2008, the entire contents of which are incorporated herein by reference. BACKGROUND [0002] Electrophysiological-based assays are used in a variety of applications, which include the detection of toxicants, drug screening, illuminating the mechanism of toxicity, neuronal injury, epilepsy studies and biosensing. Most systems used for such assays produce information in a relatively low-throughput manner. For example, patch clamp systems, have an extensive history of use in identifying specific perturbations in electrophysiological function; however, they are also well known for their extremely low throughput (<10 cells/day). On the other hand, microelectrode array (MEA) systems, which have concurrent access to both single-cell and network-level activity, are higher-throughput and less technique-dependent; however, due to their high cost and limited sample capacity (typically <5 samples/experiment), they are still, functionally, low throughput. Currently, MEAs are expensive and are typically offered in units with only one culture well (such that only one tissue sample/cellular network at a time can be studied). The use of only one culture-well severely limits the throughput with which MEAs can be used to interface and investigate electrically active cellular networks. [0003] In contrast, multiwell culture plates and plate readers are commonly used instruments in the pharmaceutical industry and are extensively used for high throughput in-vitro assays, such as screening compounds or toxicants. However, apart from enabling imaging, such transparent plates have no other function than to act as supporting structures for cell cultures and media, which eliminates the possibility of using multiwell plates for electrophysiological investigations. If electrodes could be integrated into to these transparent plates, high throughput applications like network electrophysiology can be carried out in a standard format. Integrating microelectrodes into a standard format would additionally enable compatibility with machinery in place for analysis of multiwell plates like microscopy and cell counting. [0004] King et al. and Maher et al. disclose electrode arrays integrated with multiwell plates but the electrodes used are macro-sized (4 mm wide, 1 cm long and 0.2 mm thick in the case of Maher et al.) stainless steel plates. King et al. discloses an electroporation application to introduce molecules into lipid vesicles of cell membranes and Maher et al. report stimulation of cells in-vitro for studying transmembrane potentials recorded with optical measurement techniques. These disclosures by King et al. and Maher et al., introduce electrodes into multiwell formats, but the large size of the integrated electrodes eliminate the possibility for any cell based assays that address both single and network level cellular activity. Thus, micro-scale electrodes are required for such an investigation and the invention provided herein addresses the novel integration of microelectrodes into multiwell plates, such as a multiwell culture plate, with a transparent substrate in an ANSI/SBS (American National Standards Institute/Society for Biomolecular Sciences, “Standards for Microplates”, 2004) compliant format. However, the integration of micro-scale electrodes or MEAs into transparent, large area multiwell plates presents significant manufacturing challenges. [0005] To-date, MEAs have been fabricated in both two- and three-dimensional conformations on a myriad of different substrates including flexible materials, such as poly dimethyl siloxane (PDMS), and rigid substrates, like silicon and glass. Regardless of the application or material, many of these MEAs share one significant drawback, expensive manufacturing costs. This expense is derived primarily from the packaging and assembly of the device, which is required to connect micron-sized electrodes for cellular interfacing to millimeter-sized sockets and pads for electrical processing. Such differences in scale introduce intermediate, often manual, processing steps that significantly reduce the manufacturability of MEAs. Additionally none of these known processes is truly standard (eg. Complimentary Metal Oxide Semiconductor or CMOS process for computer chips) resulting in high processing costs. SUMMARY OF THE INVENTION [0006] Provided herein are microelectrode array devices, methods for their use and methods for their manufacture. [0007] In addition to enabling high-throughput extracellular electrophysiological investigations of electrically active tissues and cultures, the approaches taken in connection with this invention address the interconnection of macro-sized sockets and pads for electrical interfacing to micro-sized electrodes for cellular interfacing utilizing two different techniques: one is a novel post-processing approach on a modified, commercially available printed circuit boards (PCBs) that enables majority of the device being built by a low-cost, large area (eg, a surface area of about 3 inches by 3 inches, or greater) process on a transparent substrate; second is a flip-chip bonding approach of a separately fabricated glass die with microelectrodes with an innovatively designed printed circuit board for the macro-sized electrical connections. Both these approaches have been designed to fit into a standard multiwell plate (ANSI/SBS 2004 standards) that measure 127.76±0.25 mm in length and 85.48±0.25 mm in width. This multiwell plate can house 6, 12, 24, 48, 96, 384, and 768 culture wells depending on the application. Multiwell plates are an integral part of the biological and pharmaceutical industries, with standardized overall dimensions covered by ANSI/SBS 2004 standards. None of these standards cover the use of electrodes. [0008] In exemplary embodiments, the electrodes are 500 μm or smaller in diameter with the space between the electrodes also being 1 mm or smaller. In addition to transparency, this small size area requires a specialized manufacturing process. Additionally, an individual multiwell MEA plate may contain hundreds to thousands of electrodes. [0009] In exemplary embodiments, the manufacturing process for multiwell microelectrode array includes post-processing or microfabrication directly onto the PCB (or package) or an integrated circuit (IC) packaging approach that combines microfabricated die with a PCB. Either technique makes use of the PCB industry, which employs standard large-area processes to achieve precise, high-density metal traces, sockets, vias and pads (minimum PCB features sizes are typically around 125 μm). Additionally, even higher electrode densities can be achieved by augmenting or post processing the PCB process with microelectromechanical (MEMS) based processing (minimum MEMS features sizes may be less than 1 μm, approximately two orders of magnitude below PCB processes). This high-density microelectrode fabrication is enabled by the small features sizes of MEMS processes and by micro-scale multilayer electrode wiring (existing MEAs use a single wiring layer). In the composite device (PCB+MEMS processing), commercial high-density electrical connectors can be used to connect to thousands of electrodes in the back/bottom layer of the multiwell MEA. Existing MEAs, due to manufacturing limitations, tend to use top-layer connectors; which reduces the number of interconnects that can be used and increases the footprint of the device to accommodate the required interconnects. The use of commercial PCB technology allows the addition of standard integrated circuits (ICs) and other components to provide improved functionality to the MEAs. These additional components may include the introduction of memory, heater, and sensor elements directly onto the multiwell MEA substrate. BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1 illustrates an exemplary embodiment of a multiwell MEA in an ANSI/SBS-compliant format. [0011] FIGS. 2A-B and 2 C-D illustrate top and side views, respectively, of post-processing on a printed circuit board. [0012] FIG. 3 illustrates a technique to enable the successful lamination with a transparent polymer, which further enables the use of inverted microscopy. [0013] FIGS. 4A-B illustrate an exemplary design of a package/substrate in a multiwell format in a package design layout and microelectromechanical systems (MEMS) post processing layout, respectively. [0014] FIGS. 5A-B illustrate an exemplary packaging approach to a multiwell MEA with side and top views, respectively. [0015] FIGS. 6A-B illustrate an exemplary design of the PCB and glass substrate with top views of the layout for the PCB and the glass substrate used in the packaging process, respectively. [0016] FIGS. 7A-B illustrate optical microscopy images of neuronal cultures grown on the MEAs at 21 and 28 days in-vitro, respectively. [0017] FIGS. 8A-B illustrate evoked electrophysiological data produced from microelectrodes within an individual culture well. DETAILED DESCRIPTION [0018] FIG. 1 illustrates an exemplary embodiment of a multiwell MEA in an ANSI/SBS-compliant format. The multiwell electrode interfaces with electronics to which it is attached to through bottom side contacts. The electronics amplify and process the raw data obtained from cellular cultures in the various wells and the data is reflected in a computer for data analysis and manipulation. [0019] FIG. 1 illustrates an exemplary MEA system 10 that has been designed to interface with a physical system such as a tissue specimen or a network of cells in a multiwell format, i.e. several wells 12 of electrodes (6, 12, 24, 48, 96, 384, and 768 with a total of 768 electrodes). This physical system is in direct contact with the microelectrodes. The multiwell microelectrodes 20 plug into a signal processing and data management system 14 which collects and analyzes the data that is generated from the cells. The combination of the cells, microelectrodes and entire system connects to a computer 16 via a data cable 18 for real time software analysis and recording. At the top of FIG. 1 is a constructed multiwell MEA system 8 . [0020] FIGS. 2A-B and 2 C-D illustrate top and side views, respectively, of post-processing on a printed circuit board. FIGS. 2A and 2B illustrate microfabrication of the multiwell MEA using a combination of a large area process like PCBs and post processing using microfabrication or MEMS techniques—top views of a PCB (obtained from a commercial vendor) and a single well of electrodes after post processing. FIGS. 2C and 2D illustrate side views for the fabrication strategies for a multiwell MEA with a large area process like PCB in combination with microfabrication techniques. [0021] FIG. 2A depicts the components of a planar MEA. The active part of a planar MEA comprises three components: (1) the electrodes or the active sites, (2) the topmost insulating layer, and (3) the micro-scale metal wiring traces. Regardless of the manufacturing strategy, the microfabrication process must account for all these three components. For the development of multiwell MEA devices, platinum black can be used for the electrodes, SU-8 or silicon dioxide (SiO 2 ) for the insulation layer, and gold for the wiring traces. The platinum black electrodes can be formed using a closed-loop electroplating process, which will produce robust electrodes with precisely matched electrical properties. The negative tone epoxy SU-8, which acts as an insulating material, has several attractive properties such as chemical stability, photolithographic definition, thermal stability and coating uniformity. It has been used as an insulation layer in commercially available MEAs from Ayanda Biosystems. Additionally, SU-8 has the added benefit of planarizing the relatively rough surfaces on PCBs substrates or flex-rigid circuits. SU-8 is an ideal material to act as an insulation layer for a polymer-substrate multiwell MEAs, which have low temperature processing requirement, though it can be used with glass or silicon substrate materials as well. Silicon dioxide is a traditional insulation material that is used in combination with rigid substrates like glass. The advantages of silicon dioxide include well characterized microfabrication techniques, low dielectric constant and pin-hole free coatings even in a nanometer scale. Although SU-8 has been used with both polymer and glass substrates for multiwell MEA fabrication, SiO 2 has been used exclusively with glass substrates ( FIGS. 5 and 6 ). [0022] With these materials in mind, provided herein are fabrication processes and strategies for a post-processing of PCB that include the minimum number of steps necessary to achieve the desired objectives, such as transparency. [0023] FIG. 2C depicts the side view of this fabrication approach. The MEA traces and recording sites can be defined using a relatively thick layer of negative resist (which will also account for the planarization of the metal on the flex circuit) and UV lithography. A biocompatible metal stack (titanium for adhesion and gold for the metal traces) can be deposited using standard metal deposition techniques and the metal will be lifted off to define the finer metal lines. In order to passivate the MEA and define the recording sites (electrodes), a thin layer of SU-8 is coated and the material is photo patterned. SU-8 is photopatterned to define the final insulation pattern. No other processing on top of this is necessary to define the insulation layer. This processing step may be followed by electrodeposition of platinum in order to reduce the impedance of the recording sites. The approach listed here has the advantage of a very simple post-processing strategy (2 mask process) to achieve a functional MEA. [0024] Surface planarization (for microfabrication) on non-standard substrates may require a slightly modified approach to the process described above. One such modified approach is illustrated in FIG. 2D . SU-8 is an excellent material for surface planarization. Spin coating a layer of SU-8 on relatively rough surface results in the reduction of surface non-uniformities. This may be used as an additional step in the beginning of the above processes to address potential problems in direct processing on PCBs. The rest of the process is same as the fabrication techniques detailed above. The additional complexity (involving one more mask) will not add significant time to the process development of multiwell microelectrode arrays. Additionally, potential cytocompatibility problems due to insufficient PCB encapsulation are improved by the addition of an extra layer of SU-8. [0025] FIG. 3 depicts a lamination technique for transparent polymer lamination on PCBs that is compatible with standard adhesives used in the industry. Acrylic-based adhesives are used to laminate Kapton onto a printed circuit board for what are called “flex-rigid” or “rigid-flex” circuits since the Kapton layer adds flexibility to what is a rigid substrate. The most common applications for flex-rigid circuits are in the fields of aerospace, military and biomedical. It offers increased reliability and reduced weight for the former two markets while offering the ability to bend and fold in tight places for biomedical applications like implants. Kapton or polyimide is a suitable polymer for these circuits due to its mechanical stiffness, and compatibility with processes for drilling and metallization. Polyethylene Terephthalate (PET) is a transparent polymer (light transmittance of 93% for 3 mil thickness; source DuPont Teijin Films) that could be utilized as an alternate to Kapton utilizing an added step (such as employing an adhesive or a mechanical operation as known to one skilled in the art) to render it compatible with standard PCB processing. The temperature of the lamination process is lowered to accommodate the low temperature requirement of PET but the time of the process is increased to ensure the reflow of this thermally set acrylic adhesive. This reflow ensures that the adhesive remains intact for any future processing. This process has been demonstrated successfully on large area substrates (eg, 12 inches by 18 inches). Several flex rigid circuits with the multiwell format can be fabricated on a single panel PCB making this process batch fabrication compatible. This batch fabrication results in lowering the cost of the PCB process with the primary cost shifting to the post processing, which is low to begin with since there are only two layers to creating the MEA. [0026] Referring now to FIGS. 4A and 4B , design layouts for the PCB, FIG. 4A , and MEMS post processing, FIG. 4B , for a 12 well multiwell MEA are illustrated. These designs can be rapidly modified to accommodate different well configurations. The circular configurations on the PCB design define holes in the FR-4 substrate that allow for bottomside transparency. Rapid design changes allow for the modification of the MEMS post processing masks, so that other well designs with electrodes can be achieved like 24, 48 and 96 well counts. [0027] FIG. 4A depicts the layout for the PCB (top side) and the masks for post processing to create the multiwell MEAs using the fabrication process described in FIGS. 2A-D . A major advantage is the flexibility of the design and fabrication processes. Specifically, design changes can be implemented rather quickly once the fabrication process has been established. A design iteration only requires two different layouts (PCB layout and MEA mask layout for two layer fabrication), and, by changing these two layouts, a wide variety of electrode counts can be fabricated. Additionally the well locations can be made ANSI/SBS-compliant by incorporating the well locations from standard documents into the designs. Thus, a change from 1×768 (one well with 768 electrodes) to 96×8 (96 wells with 8 electrodes each) or any combination in between can be constructed with little difficulty. The processes also lend to flexibility in terms of changes in electrode densities and geometries with changes only to the MEA mask layout. Furthermore, since the processes are primarily based on custom PCB/flex circuit fabrication, the integration of heaters, sensors, memory chips, and fluidic valve controls to the multi-well MEA itself can be easily accomplished, thus providing additional functionality to the final product. [0028] FIGS. 5A and 5B illustrate the concept of a packaging or flip-chip approach to a multiwell MEA with side and top views, respectively. The multilayer PCB and the glass die can be fabricated separately using batch fabrication techniques and coupled together to complete the device in an ANSI/SBS compliant format. FIG. 5A depicts a side view of the flip chip approach to multiwell MEAs. In this schematic, the two components of the multiwell MEA are depicted: a recessed three layer printed circuit board (standard rigid PCB) 50 ; and a microfabricated glass chip that has metal traces defined and insulation coated 52 . The two components are connected together using a conductive epoxy or solder layer that is screen printed on the glass substrate. The completed device is in an ANSI/SBS-compliant culture well format thereby enabling easy design changes from a 1×768 electrode format (single well) to a 96×8 electrode format (up to 96 wells). The glass substrate is fabricated in two steps: metal interconnection patterns are defined utilizing a standard metal lift-off process; an insulation process which may include either an SU-8 layer defined using photolithography or an SiO 2 layer defined using a photolithography step followed by an etch process. The rigid PCB is fabricated using a three-layer process with a bottom layer for connecting the electrodes to the multiwell electronics and two layers on top to accommodate the routing of all 768 electrodes. FIG. 5B depicts a top view of the flip chip approach to multiwell MEAs. [0029] FIGS. 6A and 6B illustrate exemplary design of the PCB and glass substrate with top views of the layout for the PCB and the glass substrate, respectively, used in the flip chip process. These designs can be rapidly modified to accommodate different well configurations. The circular configurations on the PCB design define holes in the FR-4 substrate that allow for bottomside transparency. Rapid design changes allow for the modification of the MEMS post processing masks, so that other well designs with electrodes can be achieved, such as 24, 48 and 96 well counts. [0030] FIGS. 6A and 6B illustrate a sample routing scheme for 768 electrodes in a 12-well format (each well has 64 electrodes). Both the PCB design, FIG. 6A , and the glass plate design, FIG. 6B , are shown. The interconnection between the two substrates is achieved using metal pads defined at two of the corners of both the substrates. Screen printing of a conductive material like conductive epoxy or solder is carried out utilizing standard stencil printing techniques. The glass substrate and the PCB are brought assembled together using a flip chip bonder and the entire assembly is cured to finish the flip chip process to achieve a multiwell MEA in an ANSI/SBS compliant format. [0031] FIGS. 7A and 7B are optical microscopy images of neuronal cultures grown on the MEAs at 21 days, FIG. 7A , and 28 days, FIG. 7B , in-vitro. FIGS. 7A-B depict optical microscopy images of neuronal cells from E18 cortices of rat brains cultured on a single well of the MEA devices. E18 cortices are harvested from rat brains and cells from these cortices are plated on the MEA as described in the Examples section. These devices were placed in incubators and observed after 24 hours of plating cells, at 7 days, 21 and 28 days in-vitro. The observations were carried out utilizing inverted microscopy techniques. Observations were made for neurite outgrowth and general health of the cells. At 28 days in-vitro, a live/dead assay was performed in accordance with the protocols developed by Cullen et al. to access the viability of cells in the culture dish. Images captured from this assay are also shown in FIG. 7A-B . In a multiwell embodiment of the same device, such data will be collected from all the wells simultaneously. The multiwell MEAs will ensure similar experimental conditions for such assays unlike the single well counterparts where these experiments have to be performed one at a time. This will enable a much higher throughput for applications like drug screening. [0032] FIGS. 8A-B are graphical illustrations of evoked electrophysiological data recorded from microelectrodes within an individual culture well. In this example, microelectrodes were used to both stimulate and record from neural cortical cultures. In a multiwell format, such data is collected simultaneously in dozens to hundreds of wells, dramatically increasing the throughput of electrophysiological investigations for screening applications. Extracellular electrophysiological data from excitable cells and tissues is used to perform a wide range of analyses, ranging from the collection network-level dose response curves and the identification of specific ion-channel behaviors to the quantification of neurotransmitter release. Additionally, studies in plasticity, toxicity, learning and memory, and pharmacology are further enabled with the use of MEAs. An individual microelectrode can be used to perform multiple functions simultaneously, thus it is possible to both stimulate and record from individual microelectrodes. Stimulation can be used to evoke electrical activity that would other-wise not occur under normal spontaneous conditions. In FIG. 8A , (a) cultured cortical recordings with (b) and without (a) the elimination of excess charge that builds up on the microelectrode during stimulation (known as artifacts) (scale bars: 100 μV, 10 ms, stimulus ±0.5V). In FIG. 8B , neural recordings on both the stimulating and neighboring electrodes. Arrows indicate superimposed evoked responses, and circles indicate secondary artifacts induced by crosstalk inside the recording electronics (biphasic stimulus ±0.5V). [0033] Without being limited by theory, it is believed that the devices provided herein allow for the measurement of characteristics (eg, chemical, biological, biochemical or electrophysiological) of certain samples (eg, chemical or biological) at sensitivities and/or throughput levels that cannot be achieved with currently available devices. [0034] Accordingly, provided herein are microelectrode arrays (MEAs) which are compatible with equipment or machinery intended for use with an ANSI/SBS-compliant plate, comprising a plate having one or more wells and a substrate comprising a printed circuit board (PCB), wherein said substrate further comprises one or more microelectrodes having a diameter of about 1 to about 500 microns, wherein the substrate is transparent in the vicinity of the microelectrodes and has an area of about 3 inches by about 3 inches or greater. Currently available multiwell MEA plates are restricted to electrodes that are several mm in dimension, precluding the ability to perform electrophysiological measurements, micro-stimulation, or high-resolution impedance analysis. [0035] In certain embodiments, the plate is comprised of a transparent material, such as glass or plastic. [0036] In certain embodiments, the plate comprises a single well. [0037] In certain embodiments, the plate is a multiwell plate. In particular embodiments, the multiwell plate has an area of about 3 inches by about 3 inches or greater. In other embodiments, the multiwell plate has an area of about 3 inches by about 5 inches or greater, about 3 inches by about 6 inches or greater, about 4 inches by about 4 inches or greater, about 4 inches by about 5 inches or greater, about 5 inches by about 5 inches or greater, about 5 inches by about 7 inches or greater or about 6 inches by about 6 inches or greater. [0038] In certain embodiments, the microelectrode array comprises multilayer microelectrode wiring. [0039] In certain embodiments, the microelectrodes are integrated into one or more wells of the multiwell plate. In certain embodiments, the microelectrodes are adhered to or embedded into the substrate. [0040] In certain embodiments, the substrate is transparent in the vicinity of the microelectrodes, such that biological specimens can by analyzed using the MEA in combination with inverted microscopy, inverted fluorescent microscopy, inverted environmental microscopy or inverted cell counting techniques. In certain embodiment, the entire substrate is transparent. In one embodiment, the wells of the multiwell plate are transparent. In another embodiment, the area of the plate in which the microelectrodes are integrated into or attached to is transparent. In particular embodiments, the substrate or plate is transparent such that it allows for about 90%, about 92%, about 94%, about 96%, about 98%, about 99%, about 99.9% light transmittance through the substrate In one embodiment, one or more microelectrodes is itself transparent. Transparency can be measured by methods known to one skilled in the art using a spectrophotometer. [0041] In certain embodiments, the microelectrode array comprises a multiwell plate having anywhere from 4 to 1536 wells, 4 to 384 wells or 4 to 96 wells. In specific embodiments, the multiwell microelectrode array comprises a multiwell plate having 4, 96, 384 or 1536 wells. [0042] In certain embodiments, the multiwell plate is of a size described by ANSI/SBS (ie, is ANSI-SBS-compliant). In certain embodiments, the multiwell plate is compatible with equipment or machinery intended for use with ANSI/SBS-compliant plates. Because it is possible that plate size could be altered without significantly affecting the utility of a microelectrode array, devices including a plate with a size outside of ANSI/SBS standards are intended to be within the scope of the present disclosure. [0043] In certain embodiments, the multiwell plate comprises from 1 to 768 or from 1 to 384 electrodes per well. [0044] In certain embodiments, the multiwell plate comprises 384 electrodes per well in a 2 well configuration to 1 electrode per well in a 1536 well configuration. [0045] In certain embodiments, the multiwell plate has a length of about 127.76 mm±0.25 mm (5.0299 inches±0.0098 inches), a width of about 85.48 mm±0.25 mm (3.3654 inches±0.0098 inches) and a thickness of about 14.35 mm±0.25 mm (0.5650 inches±0.0098 inches). [0046] In certain embodiments, the diameter of the microelectrodes is about 1 to about 500 microns, about 1 to about 450 microns, about 1 to about 400 microns, about 1 to about 350 microns, about 1 to about 300 microns, about 10 to about 300 microns, about 50 to about 300 microns or about 100 to about 200 microns. [0047] In certain embodiments, the microelectrodes have a length of about 1 to about 500 microns, about 1 to about 450 microns, about 1 to about 400 microns, about 1 to about 350 microns, about 1 to about 300 microns, about 10 to about 300 microns, about 50 to about 300 microns or about 100 to about 200 microns. [0048] In certain embodiments, the microelectrodes have a thickness of about 10 nanometers to 1 micron, about 50 nanometers to about 1 micron, about 100 nanometers to about 1 micron, about 200 nanometers to about 1 micron, about 300 nanometers to about 1 micron, about 400 nanometers to about 1 micron, about 500 nanometers to about 1 micron or about 750 nanometers to about 1 micron. [0049] In certain embodiments, neighboring microelectrodes have a spacing of about 10 microns to about 1 mm, about 20 microns to about 1 mm, about 50 microns to about 1 mm, about 100 microns to about 1 mm, about 200 microns to about 1 mm, about 300 microns to about 1 mm, about 400 microns to about 1 mm, about 500 microns to about 1 mm or about 750 microns to about 1 mm. [0050] In certain embodiments, the are made of titanium, chromium, titanium/gold, chromium/gold, platinum, indium tin oxide, rhodium, silver, palladium, nickel, copper, poly(3,4-dioctyloxythiophene) (p-dot) or a combination thereof. [0051] In certain embodiments, the PCB is laminated with a transparent polymer membrane. In certain embodiments, the polymer is Polyethylene Terephthalate (PET). In certain embodiments, the polymer membrane has a thickness of about 10 to about 100 microns). [0052] In certain embodiments, the microelectrode arrays allow for the analysis of 4 to 1536 samples/experiment, 4 to 384 samples/experiment or 4 to 96 samples/experiment. [0053] In certain embodiments, the microelectrode arrays allow for high-sensitivity and high spatial resolution impedance-based assays. Additionally, the use of multiple microelectrodes for impedance analysis provides redundancy, by improving the likelihood that cultures or tissues will adequately cover several electrodes, which may dramatically improve the yield and accuracy of impedance-based assays. [0054] In certain embodiments, the microelectrode arrays allow for micro-stimulation, for eliciting controlled, evoked responses from tissues and cultures under investigation. Such stimulation can be applied simultaneously during the recording and acquisition of extracellular electrophysiological data. Further, micro-stimulation can be used to evoke both field and action potentials as well as to perform a wide-range of threshold-based assays. Accordingly, such methods for using the microelectrode arrays disclosed herein are provided herein. [0055] In certain embodiments, the microelectrode arrays allow for concurrent access to both single-cell and network-level activity of a sample. In certain embodiments, the microelectrode arrays allow for the detection and/or monitoring of electrically active cellular networks. Accordingly, such methods for using the microelectrode arrays disclosed herein are provided herein. [0056] In certain embodiments, the total number of microelectrodes in an array is from 1 to 1536, from 1 to 768, from 1 to 384 or from 1 to 96. In other embodiments, the total number of microelectrodes in an array is a multiple of 96, 384, 786 or 1536, such as a multiple of a whole number between 1 and 5000, between 1 and 4000, between 1 and 3000, between 1 and 2000, between 1 and 1000, between 1 and 500, between 1 and 100, between 1 and 50 or between 1 and 10. [0057] Further provided herein are methods for measuring in vitro or in vivo electrophysiological activity, impedance characteristics, extracellular network activity of a biological specimen (eg, a cell, tissue and/or culture of the following varieties: vertebrate and invertebrate neural, muscle fibers, cardiac, pancreatic islet, osteoblasts, osteoclasts) using a microelectrode array provided herein. Specifically, provided herein are methods for measuring in vitro or in vivo electrophysiological activity, impedance characteristics or extracellular network activity of a cell or tissue, comprising contacting said cell or tissue with a MEA provided herein. In certain embodiments, the biological specimen is placed or cultured in one or more wells of an MEA provided herein and electrophysiological activity, impedance characteristics or extracellular network activity of the biological sample is detected and/or measured. [0058] Further provided herein are methods for microscopy and/or cell counting using a microelectrode array provided herein. In particular embodiments, the microelectrode arrays provided herein are compatible with an optical plate reader. [0059] Further provided herein are methods for in vitro or in vivo micro-stimulation of a biological specimen (eg, a cell, tissue and/or culture of the following varieties: vertebrate and invertebrate neural, muscle fibers, cardiac, pancreatic islet, osteoblasts, osteoclasts). In certain embodiments, provided herein are methods for eliciting controlled, evoked responses from a biological specimen. Such stimulation can be applied simultaneously during the recording and acquisition of extracellular electrophysiological data. Further provided herein are methods for micro-stimulation of a biological specimen and measuring (including recording and/or acquiring) a response (eg, an extracellular electrophysiological response). Further, micro-stimulation can be used to evoke both field and action potentials as well as to perform a wide-range of threshold-based assays. Accordingly, such methods for using the microelectrode arrays disclosed herein are provided herein. Specifically, provided herein are methods for micro-stimulating a cell or tissue comprising contacting said cell or tissue with a MEA provided herein and exposing said cell or tissue to an electrical current originating from said MEA. In another embodiment, such methods further comprise recording and/or acquiring extracellular electrophysiological data from said cell or tissue. In certain embodiments, the biological specimen is placed or cultured in one or more wells of an MEA provided herein and the biological specimen is micro-stimulated by the MEA (eg, by exposing the biological specimen to an electrical current originating from the MEA). Further provided herein are methods for manufacturing a microelectrode array provided herein. Post Processing Method [0060] Provided herein are methods for manufacturing a microelectrode array including the steps of: 1. providing a PCB and a mask for microelectromechanical systems (MEMS) post processing (wherein in certain embodiments, the PCB is a flex-rigid PCB, and in other embodiments, the PCB and mask are designed to be compatible with an ANSI/SBS-compliant plate); 2. laminating the PCB with a transparent polymer membrane (wherein in certain embodiments, the PCB is a flex-rigid PCB fabricated using a modified process for lamination of PET as described herein); 3. defining vias in the polymer membrane (in certain embodiments, such that it becomes possible to create functional, electrical interconnections between the top-side of the polymer membrane, such as PET, and the underlying PCB); and 4. MEMS processing utilizing the PCB as a substrate to create microelectrodes (such as in a multiwell fashion). In certain embodiments, the first layer defines the metal traces on the flex-rigid board and the second layer defines the insulation on top of the defined metal. [0065] Flip-Chip Method [0066] Further provided herein are methods for manufacturing a microelectrode array including the steps of: 1. Defining or modifying a PCB (such as a standard rigid PCB) to allow for insertion of a multiwell glass plate; 2. providing a photolithography mask for processing a multiwell glass MEA (such as a mask designed to be compatible with an ANSI/SBS-compliant multiwell glass plate); 3. optionally fabricating the PCB utilizing standard commercial techniques; 4. microfabricating the multiwell glass MEA to provide at least two layers, wherein the first (bottom) layer defines metal traces and the second (top) layer defines the insulation; and 5. attaching the multiwell glass MEA to the PCB utilizing integrated circuit (IC) packaging techniques, creating electrical connections between the PCB and glass MEA. [0072] In exemplary embodiments, the disclosed fabrication techniques, devices and methods of use may comprise at least one of the following elements: i. The device: a multiwell MEA device itself, may be any multiwell plate (more than 4 wells) with greater than 4 electrodes per well, with electrode sizes of 500 μm or less in diameter, with inter-electrode distances (center-to-center) of about 1 mm or less. Currently available multiwell MEA devices do not have the capability to define electrodes to the size disclosed in this invention. ii. The fabrication process: fabricating micro-scale electrodes on printed circuit board (PCB), Kapton flex board, hybrid circuit board technology, flip chip techniques, multi- or single-layer glass technology (i.e. Micronit Inc). More specifically, using printed circuit boards (of any kind) or multilayer glass technology with vias as a substrate for single-well or multiwell MEAs. PCB substrate materials may include, but are not limited to, the following: FR-4, FR-2, Kapton, Polyimide, and Teflon, and Polyethylene Terephthalate (PET). Currently available multiwell MEA devices in large-area ANSI/SBS compliant formats do not utilize microfabrication technologies. iii. Transparency: in most cell culture applications it is desirable to evaluate or observe the culture with an inverted microscope. Thus, bottom-side transparency, the ability to see through the bottom of the device to observe the underside of the cells, is a desired feature. Laminatable, translucent films such as Kapton and transparent films such as PET (among others) pressed over a hole in the package/PCB substrate to enable inverted microscopy. Such thin films can provide superior optical characteristics like a high degree of light transmittance through the substrate. Glass substrates provide this advantage as well due to light transmission through the substrate. Current multiwell configurations do not disclose this feature. iv. Applications: using the multiwell MEA as a high throughput instrument for the investigation of electrically active tissue (including, but not limited to, neural and cardiac cells, cellular networks and tissue, spinal cultures and tissue, and muscle tissue), which may have specific applications in drug discovery, basic science, epilepsy research, biosensing, high throughput network or tissue analysis. v. Connectivity: the use of a PCB or glass substrate as a biochip packaging element and sensor substrate provides an avenue to create bottom side electrical contact pads for ‘outside-world’ connections or sockets. Bottom side connectivity is made affordable because of via processing readily available in standard PCB and glass-via processes. Additionally, bottom-side connector pads significantly reduce the size of the sensor array, as the connector/socket pads are now on a different plane than the electrodes and can lie directly under the sensor array (outside the transparency region, if applicable). Bottom side metal patterning also creates an opportunity to create a metal heater surface just below the cell culture. Examples [0078] A fully microfabricated, packaged and assembled multiwell MEA is shown in FIG. 1 (right hand side). The components of this system include a microfabricated MEA that is constructed utilizing techniques described herein, such as a flip chip package including a glass die with a printed circuit board or a post processed PET-based PCB. This multiwell MEA docks into a system that consists of electronics and signal processing units plus data management/software analysis functionalities. [0079] Biological assays have been conducted using these MEAs to evaluate neuronal cytocompatibility. The various steps for these experiments are described below. 1. To remove potential leachants from microfabrication, the devices were sequentially rinsed in sterile ethanol for 5 minutes, followed by rinsing in sterile DI water for 5 minutes. The multiwell MEAs were then soaked in sterile DI water for up to 72 hours (with a change in DI water every 24 hours). The DI water was then discarded and the MEAs were subjected to a rinse with sterile ethanol. This was followed by an 8 hour dehydration bake at 60° C. in an oven. This bake completed the steps for removing potential leachants from microfabrication and PCB manufacturing. 2. Before plating cells, the MEAs were subject to a 1 min oxygen plasma treatment. This process improves the adherence of cells to the MEAs. This was followed by the coating of 50 μg/mL poly-D-lysine for 2 hrs at 37° C. on the MEA surfaces. Neuronal cells from E18 cortices of rats were cultured on the MEAs with a density of 3×10 5 cells/cm 2 . Cells were seeded at the appropriate density in 50 μL of neurobasal media directly on to the center of the MEA devices. Cells were allowed to attach for 30 min at 37° C., then an additional 950 μL of neurobasal media was added to the device. Devices with individual lids were placed inside Petri dishes to minimize media evaporation. The devices with cells were studied using optical microscopy at 1 day, 4 days, 7 days and 21 days in-vitro for neurite outgrowth and general health of the culture. Images of the cell cultures were captured. At 28 days in-vitro live/dead assays were performed in accordance with the procedures described by Cullen et al. [0082] FIG. 7 depicts optical and fluorescent microscopy images of cultures of neuronal cells in an individual well at 21 and 28 days in-vitro. [0083] The extracellular electrode activity from cultured neuronal cells is indicated in FIG. 8 . This depicts activity from cells after stimulation was performed with and without the elimination of stimulus artifact.

4y

CROSS-REFERENCE TO RELATED APPLICATION This application is a divisional of application Ser. No. 09/652,878, filed Aug. 31, 2000, now U.S. Pat. No. 7,077,733, issued Jul. 18, 2006. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to subpad supports in web format and belt format polishing apparatus. Particularly, the present invention relates to subpad supports including nonadhesive subpad securing elements and to polishing apparatus including the subpad supports. The present invention also relates to assemblies including a subpad and a subpad support of the present invention, as well as to methods of assembling a subpad with, securing a subpad to, removing a subpad from, and replacing a subpad on a subpad support of the present invention. 2. State of the Art Web format polishing apparatus typically include a wafer support and a polishing pad. The wafer support is typically configured to hold a semiconductor wafer, to bring the wafer into contact with the polishing pad, and to rotate the wafer while the wafer is in contact with the polishing pad so as to create friction between the wafer and the polishing pad and, thereby, effect polishing of one or more layers on the wafer. As used herein, the term “polishing” encompasses removal of material from a semiconductor wafer. “Polishing,” as used herein, need not achieve a certain surface finish or planarity. A subpad, located on the opposite side of the polishing pad from the wafer support, is configured to prevent the formation of defects on a wafer secured to the wafer support during polishing thereof, as well as to cushion the polishing pad and wafer being polished so as to prevent damage to the wafer during polishing. The subpad is held in place by a subpad support and, conventionally, has been secured to the subpad supports by way of an adhesive material. Fresh portions of a web format, film-type polishing pad are supplied by a supply reel of the web format polishing apparatus, while used portions of the web format polishing pad are taken up on a take-up reel of the apparatus. Typically, the positions of supply reels and take-up reels on conventional web format polishing apparatus are fixed relative to the remainder of these apparatus. As a subpad wears, it must be replaced. Typically, in order to remove a subpad from a web format polishing apparatus, the web format polishing pad must either be cut or slack formed in the polishing pad by, for example, loosening the web format pad from the supply reel of the polishing apparatus without winding the pad around the take-up reel. Creating slack in a web format polishing pad facilitates pulling of the polishing pad away from the subpad. When a web format polishing pad is cut or given slack, it is common that a portion of the polishing pad is damaged and, thus, that portion of the polishing pad is wasted. In addition, as the subpad is typically secured to the subpad support with an adhesive material, removal of the subpad from the subpad support is often very difficult since the subpad may rip or need to be scraped from the subpad support. Belt format polishing apparatus are very similar to web format polishing apparatus, with the major exception being that the polishing pad is in the format of a continuous belt that may be recycled, rather than a web that is supplied from a supply reel and, after use, taken away on a take-up reel. In order to gain access to a subpad of a belt format polishing apparatus, the belt format polishing pad is removed from the polishing apparatus, which is time consuming and may result in damage to the pad, or the pad may be stretched, which may also damage the pad. Damage that may occur to a belt format polishing pad as a subpad is removed and replaced is, however, even more costly than similar damage to a web format polishing pad because a damaged belt format polishing pad must be completely replaced. The inventor is not aware of a subpad support to which a subpad may be nonadhesively secured and from which a subpad may be readily removed. Moreover, the inventor is not aware of a web format or belt format polishing apparatus configured to facilitate subpad removal and replacement without a significant potential for damaging the polishing pad. BRIEF SUMMARY OF THE INVENTION The present invention includes a subpad support with a retention element for removably, nonadhesively securing a subpad thereto, as well as web format and belt format polishing apparatus including the subpad support. The subpad support of the present invention includes a subpad supporting surface and a subpad retention element. The subpad supporting surface is configured to receive a backing of a subpad. The subpad retention element is configured to nonadhesively secure a subpad to the subpad support. The subpad retention element may be configured to at least partially engage a periphery of a subpad, mechanically engage a backing of a subpad, apply a negative pressure to a backing of a subpad through the subpad support, or otherwise nonadhesively secure a subpad to the subpad support. The subpad support may also include one or more lips, columns, or other lateral confinement structures protruding from the supporting surface thereof and that are configured and located so as to at least partially prevent lateral movement of a subpad relative to the subpad support to which the subpad is secured. To facilitate the releasable securing of a subpad to the subpad support, the subpad may include a substantially rigid structure on the backing thereof. The substantially rigid structure may be secured to the backing of the subpad or formed by a denser region of the material of the subpad. If the substantially rigid structure is secured to the backing of the subpad, a material such as a polymer, a metal, a glass, or a ceramic may be used as the substantially rigid structure. Polishing apparatus including the subpad of the present invention are also within the scope of the present invention. A polishing apparatus incorporating teachings of the present invention may include a component that at least partially moves the polishing pad of the apparatus away from the subpad support thereof, as well as a subpad secured to the subpad support. In a web format polishing apparatus, such a component may include, by way of example only and not to limit the scope of the present invention, a releasable latch that secures one or both of the supply reel and the take-up reel to the remainder of the polishing apparatus. In addition, such an exemplary polishing apparatus may also include a member that effects the controlled movement of one or both of the supply and take-up reels and, thus, the polishing pad away from the remainder of the polishing apparatus. Exemplary members include, but are not limited to, one or more hydraulic pistons, gear drive mechanisms, and screw drive mechanisms. Methods of assembling and securing a subpad to the subpad support, removing a subpad from the subpad support, and replacing a subpad on the subpad support are also within the scope of the present invention, as are methods of at least partially moving a polishing pad away from a subpad support so as to facilitate such assembly, securing, removal, and replacing. Other features and advantages of the present invention will become apparent to those of skill in the art through consideration of the ensuing description, the accompanying drawings, and the appended claims. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a perspective assembly view illustrating an exemplary embodiment of a subpad support incorporating teachings of the present invention and a subpad configured to be secured to the subpad support by way of complementary threads on the subpad and the subpad support; FIG. 2 is a perspective view of another exemplary embodiment of an assembly of a subpad support that includes a clamping member configured to engage at least a portion of a periphery of a subpad; FIG. 3 is a cross-sectional representation of an embodiment of a subpad support-subpad assembly wherein the subpad support includes clamping members configured to engage recessed portions of a complementary subpad; FIG. 4 is a cross-sectional representation of yet another exemplary embodiment of an assembly including a subpad support and a subpad of the present invention, wherein the subpad support is configured to apply a relatively negative pressure to the backside of the subpad to secure the subpad thereto; FIG. 5 is a partial perspective view of an embodiment of a subpad support configured to slidingly engage a complementarily configured subpad; FIG. 6 is a partial top view of an embodiment of subpad support with recesses and slots configured to receive tabs protruding from the periphery of a complementarily configured subpad; FIGS. 7A and 7B illustrate still another embodiment of subpad support and subpad incorporating teachings of the present invention, wherein the subpad support includes keyhole-shaped recesses configured to receive headed studs protruding from the backing of the subpad; FIGS. 8 and 8A are schematic representations of a belt format polishing apparatus incorporating teachings of the present invention, depicting at least partial movement of the polishing pad thereof away from the subpad support thereof; and FIGS. 9 and 9A are schematic representations of a belt format polishing apparatus incorporating teachings of the present invention, depicting movement of the polishing pad thereof away from the subpad support thereof. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 1 , a first exemplary embodiment of a subpad support 10 incorporating teachings of the present invention is illustrated. Subpad support 10 includes a supporting surface 12 and a retention element 14 . Supporting surface 12 is configured to engage a backing 22 of a subpad 20 . Retention element 14 is configured to secure subpad 20 to subpad support 10 . Subpad support 10 may also include one or more lips 16 protruding therefrom and positioned so as to facilitate the alignment of subpad 20 with subpad support 10 during assembly thereof or to at least partially prevent lateral movement of subpad 20 relative to supporting surface 12 during use. Retention element 14 , as illustrated, is configured to mechanically engage a corresponding, complementary structure of a known type, such as the illustrated threaded locking element 24 , on backing 22 of subpad 20 . Upon interconnecting retention element 14 and locking element 24 and rotating locking element 24 relative to retention element 14 , retention element 14 and locking element 24 interlock so as to secure subpad 20 to subpad support 10 . As illustrated, locking element 24 is secured to a backing 22 of subpad 20 by known means, such as with a suitable adhesive. Alternatively, locking element 24 may be integral with backing 22 . Backing 22 may be formed from a relatively denser region of the same material as the remainder of subpad 20 , which may be formed from a material such as closed-cell polyurethane foam, and may be integral therewith, or may comprise a separate element secured to the remainder, or contact surface 23 , of subpad 20 . Alternatively, backing 22 may be formed from another polymer (e.g., polycarbonate), a metal, a ceramic, or any other suitable material, different from the material of contact surface 23 , which cushions a wafer during polishing thereof. A backing 22 that is separate from the remainder of subpad 20 may be secured thereto as known in the art, such as by use of adhesives or by thermally bonding contact surface 23 of subpad 20 to backing 22 thereof. Turning now to FIG. 2 , another embodiment of a subpad support 10 ′ according to the present invention is illustrated. Subpad support 10 ′ includes a supporting surface 12 ′ and a retention element 14 ′. Again, supporting surface 12 ′ is configured to engage a backing 22 ′ of a subpad 20 ′ to be assembled with subpad support 10 ′. In addition, retention element 14 ′ is configured to mechanically secure a subpad 20 ′ to subpad support 10 ′. Retention element 14 ′ of subpad support 10 ′ includes a clamping member 15 ′ that is configured to be positioned around the periphery 21 ′ of at least a rigid backing 22 ′ of subpad 20 ′ upon assembly of subpad 20 ′ with subpad support 10 ′ and to be biased against periphery 21 ′ so as to secure backing 22 ′ against supporting surface 12 ′ while substantially maintaining the planarity of contact surface 23 ′ of subpad 20 ′ and, thus, the planarity of an area of a polishing pad to be supported by subpad 20 ′. In addition, clamping member 15 ′ at least partially prevents lateral movement of subpad 20 ′ relative to supporting surface 12 ′. Again, subpad 20 ′ includes a cushioning contact surface 23 ′ and a substantially rigid backing 22 ′. Backing 22 ′ may be formed from a dense region of the same material as contact surface 23 ′ or from another material, such as another polymer, a metal, a ceramic, or another suitable material. If backing 22 ′ is formed from the same material as contact surface 23 ′, backing 22 ′ may be integral with contact surface 23 ′ or a separate element that is secured to contact surface 23 ′. Of course, if another material is used to form backing 22 ′, backing 22 ′ is secured to contact surface 23 ′. Backing 22 ′ and contact surface 23 ′ of subpad 20 ′ may be secured to one another by known means, such as by use of a suitable adhesive material or by thermally bonding backing 22 ′ and contact surface 23 ′ to one another. Another embodiment of subpad support 10 ″ is shown in FIG. 3 . Subpad support 10 ″ includes a supporting surface 12 ″ that is configured to engage a backing 22 ″ of a subpad 20 ″. Subpad support 10 ″ also includes retention elements 14 ″ that are configured to clamp onto corresponding receptacles 26 ″ recessed in periphery 21 ″ of subpad 20 ″. Each receptacle 26 ″, along with backing 22 ″, forms a lip 27 ″, which a corresponding retention element 14 ″ engages upon being disposed in a clamping position. Upon engaging lips 27 ″ with retention elements 14 ″, backing 22 ″ of subpad 20 ″ is held against supporting surface 12 ″ of subpad support 10 ″. FIG. 4 illustrates yet another embodiment of a subpad support 10 ′″ incorporating teachings of the prevent intention. As the previously described subpad support embodiments, subpad support 10 ′″ includes a supporting surface 12 ′″ and a retention element 14 ′″. Subpad support 10 ′″ may also include one or more columns 16 ′″, lips, or other structures protruding from supporting surface 12 ′″. Columns 16 ′″ are preferably configured so as to laterally surround a periphery 21 ′″ of subpad 20 ′″ upon assembly thereof with subpad support 10 ′″. Columns 16 ′″ are configured to align a subpad 20 ′″ with subpad support 10 ′″, to substantially laterally surround a subpad 20 ′″ assembled with subpad support 10 ′″, or to at least substantially inhibit subpad 20 ′″ from moving laterally relative to supporting surface 12 ′″. Supporting surface 12 ′″ is configured to engage a backing 22 ′″ of a subpad 20 ′″ upon assembly of subpad 20 ′″ with subpad support 10 ′″. Retention element 14 ′″ employs a negative pressure to secure a subpad 20 ′″ to subpad support 10 ′″. Retention element 14 ′″ includes one or more apertures 30 formed through subpad support 10 ′″ from supporting surface 12 ′″ to an opposite surface 18 ′″. Apertures 30 communicate with a negative pressure, or vacuum, source 34 by way of a negative pressure conduit 32 between apertures 30 and negative pressure source 34 . As illustrated in FIG. 4 , retention element 14 ′″ also includes a chamber 35 formed within subpad support 10 ′″ and communicating with each aperture 30 . In turn, chamber 35 communicates with conduit 32 by way of a connection port 37 on subpad support 10 ′″. Alternatively, each aperture 30 of a retention element 14 ′″ incorporating teachings of the present invention may communicate with negative pressure source 34 by way of separate conduits 32 . In any event, retention element 14 ′″ secures a subpad 20 ′″ to supporting surface 12 ′″ of subpad support 10 ′″ by applying a negative pressure to backing 22 ′″ of subpad 20 ′″ through apertures 30 formed in subpad support 10 ′″. With reference to FIG. 5 , a subpad support 110 configured to receive a rectangular subpad 120 is illustrated. Subpad support 110 includes a recessed retention element 114 that is continuous with at least one end of subpad support 110 . Retention element 114 includes elongated retention slots 115 at opposite sides thereof. Retention slots 115 are configured to engage corresponding, opposite ends of a complementarily configured subpad 120 upon sliding subpad 120 in the direction of arrow A to position backing 122 of subpad 120 in substantial contact with supporting surface 112 of subpad support 110 and to effect engagement of subpad 120 by retention element 114 . Accordingly, retention slots 115 may extend laterally beneath a supporting surface 112 of subpad support 110 so as to engage thin or tapered edges 125 of subpad 120 . As shown in FIG. 6 , a subpad support 110 ′ incorporating teachings of the present invention may include a subpad receptacle 115 ′ formed in a supporting surface 112 ′ of subpad support 110 ′ and configured to receive at least a backing (not shown) of a complementarily configured subpad 120 ′. In the illustrated embodiment of subpad support 110 ′, retention elements 114 ′ are disposed around the periphery 116 ′ of receptacle 115 ′ and include recesses 114 a ′ and slots 114 b ′ that are continuous with receptacle 115 ′. Recesses 114 a ′ are formed in supporting surface 112 ′ and, upon introduction of the backing of subpad 120 ′ into receptacle 115 ′, are configured to receive tabs 128 ′ that protrude laterally from periphery 121 ′ of subpad 120 ′, in a plane substantially parallel to the plane of subpad 120 ′, and are located proximate the backing of subpad 120 ′. Retention elements 114 ′ also include slots 114 b ′ that are continuous with recesses 114 a ′ and that underlie supporting surface 112 ′. Upon sliding of subpad 120 ′ in the direction of arrow B relative to subpad support 110 ′, retention tabs 128 ′ are positioned within slots 114 b ′ and subpad 120 ′ is engaged by subpad support 110 ′. Another embodiment of subpad support 110 ″ and complementary subpad 120 ″ incorporating teachings of the present invention is illustrated in FIGS. 7A and 7B . Subpad support 110 ″ includes a supporting surface 112 ″ with a series of keyhole-shaped retention elements 114 ″ formed therein. Retention elements 114 ″ include an enlarged end 114 a ″ and a narrower, elongated slot 114 b ″ formed through and continuous with supporting surface 112 ″, as well as a receptacle 114 c ″ underlying supporting surface 112 ″, enlarged end 114 a ″, and elongated slot 114 b ″. Enlarged end 114 a ″ of each retention element 114 ″ is configured to receive a head 128 a ″ of a corresponding retention stud 128 ″ that protrudes from a backing 122 ″ of subpad 120 ″. Slot 114 b ″ is narrower than end 114 a ″ and is configured to receive a neck 128 b ″ of retention stud 128 ″ as head 128 a ″ is positioned within the portion of receptacle 114 c ″ that underlies slot 114 b ″. As shown in FIGS. 7A and 7B , retention elements 114 ″, including slot 114 b ″ and receptacle 114 c ″ thereof, may be slightly curved so as to facilitate engagement of a subpad 120 ″ by subpad support 110 ″ upon slight rotation of subpad 120 ″ in the direction of arrow C relative to subpad support 110 ″. Alternatively, slot 114 b ″ and receptacle 114 c ″ of a retention element 114 ″ may be angled so as to facilitate the retention of a complementary retention stud 128 ″ therein. Referring now to FIGS. 8 , 8 A, 9 , and 9 A, subpad support 10 may be included in a web format polishing apparatus 40 , illustrated in FIGS. 8 and 8A , or in a belt-type polishing apparatus 40 ′, shown in FIGS. 9 and 9A . As shown in FIG. 8 , subpad support 10 of polishing apparatus 40 is positioned adjacent a web format polishing pad, which is referred to herein and known in the art as a “web” 42 . Polishing apparatus 40 also includes a supply reel 44 from which fresh portions of web 42 are supplied, as well as a take-up reel 46 , which receives previously used portions of web 42 . In use of polishing apparatus 40 , a semiconductor device structure 1 is brought into frictional contact with web 42 , on an opposite side thereof from subpad support 10 . As semiconductor device structure 1 is polished at least in part by web 42 , the portion of web 42 that is being used to polish semiconductor device structure 1 is supported from beneath by a subpad 20 assembled with subpad support 10 . Web 42 and subpad 20 of polishing apparatus 40 are positioned in close proximity to one another. Polishing apparatus 40 includes a polishing pad movement element 50 , which is also referred to herein as a subpad access element, to effect the movement of web 42 at least partially away from subpad 20 so as to avoid physical contact of an operator with web 42 while facilitating access to a worn or damaged subpad 20 . As illustrated in FIGS. 8 and 8A , polishing pad movement element 50 is associated with at least one of supply reel 44 and take-up reel 46 of polishing apparatus 40 . Polishing pad movement element 50 preferably effects the movement of web 42 away from subpad support 10 in a controlled manner and at a controlled rate to minimize stress on web 42 . By way of example, and not to limit the scope of the present invention, known apparatus that may be used as polishing pad movement element 50 include hydraulic pistons, screw drive motors, gear drive motors, and the like. Polishing apparatus 40 may also include a latch 52 or other known releasable locking element that is configured to prevent movement of web 42 away from subpad 20 and subpad support 10 when such movement is not desired. In addition, if polishing pad movement element 50 moves one end 42 a of web 42 while the other end 42 b of web 42 remains substantially stationary, end 42 b may be pivotally connected to apparatus 40 , such as by a pivot pin 54 ′ that connects one conveyor support 48 to a fixed structure of apparatus 40 or otherwise, as known in the art (see FIGS. 9 and 9A ). Referring now to FIGS. 9 and 9A , polishing apparatus 40 ′ includes a belt format polishing pad, which is referred to herein and known in the art as a “belt” 42 ′. Belt 42 ′ may be continually moved around conveyor supports 48 to supply fresh or newly conditioned portions of belt 42 ′ for use in polishing a semiconductor device structure 1 . As semiconductor device structure 1 is brought into frictional contact with belt 42 ′ to effect polishing of semiconductor device structure 1 , the portion of belt 42 ′ that is being used to polish semiconductor device structure 1 is supported from beneath by a subpad 20 assembled with subpad support 10 . As shown in FIG. 9 , belt 42 ′ and subpad 20 are positioned very closely to one another. In order to avoid physical contact by an operator with belt 42 ′ to gain access to a worn or damaged subpad 20 to remove and replace the same on subpad support 10 , polishing apparatus 40 ′ is supplied with a polishing pad movement element 50 ′ that effects the movement of belt 42 ′ at least partially away from subpad 20 . As illustrated in FIGS. 9 and 9A , polishing pad movement element 50 ′ is associated with at least one conveyor support 48 of polishing apparatus 40 ′. Polishing pad movement element 50 ′ preferably effects the movement of belt 42 ′ away from subpad support 10 in a controlled manner and at a controlled rate. Examples of known apparatus that are useful as polishing pad movement element 50 ′ include hydraulic cylinders, pneumatic cylinders, screw drive motors, gear drive motors, and the like. Polishing apparatus 40 ′ may also include a latch 52 ′ configured to prevent movement of belt 42 ′ away from subpad 20 and subpad support 10 when such movement is not desired. In addition, if polishing pad movement element 50 ′ moves one end 42 a ′ of belt 42 ′ while the other end 42 b ′ of belt 42 ′ remains substantially stationary, end 42 b ′ may be pivotally connected to apparatus 40 ′, such as by a pivot pin 54 ′ that connects one conveyor support 48 to a fixed structure of apparatus 40 ′ or otherwise, as known in the art. An example of the manner in which a subpad 20 is removed from subpad support 10 of polishing apparatus 40 ′ and replaced on subpad support 10 is described with continued reference to FIGS. 9 and 9A . Latch 52 ′ of polishing apparatus 40 ′ is positioned so as to facilitate the movement of end 42 a ′ of belt 42 ′ while end 42 b ′ of belt 42 ′ pivots around pivot pin 54 ′, thereby at least partially moving belt 42 ′ away from subpad 20 and subpad support 10 so as to facilitate access to subpad 20 . Belt 42 ′ is then at least partially moved away from subpad 20 and subpad support 10 with the assistance of or by way of polishing pad movement element 50 ′. Of course, apparatus 40 ′ could be configured such that both ends 42 a ′, 42 b ′ of belt 42 ′ may be moved so as to effect movement of belt 42 ′ away from subpad support 10 . Next, subpad 20 is released by retention element 14 (see, e.g., FIGS. 1-3 ) and disassembled from subpad support 10 . Another subpad 20 may be assembled with subpad support 10 and secured thereto by retention element 14 . Belt 42 ′ may then be repositioned adjacent subpad 20 and subpad support 10 with the assistance or by way of polishing pad movement element 50 ′. Latch 52 ′ may be repositioned so as to secure belt 42 ′ in place. Although the foregoing description contains many specifics, these should not be construed as limiting the scope of the present invention, but merely as providing illustrations of some of the presently preferred embodiments. Similarly, other embodiments of the invention may be devised which do not depart from the spirit or scope of the present invention. Features from different embodiments may be employed in combination. The scope of the invention is, therefore, indicated and limited only by the appended claims and their legal equivalents, rather than by the foregoing description. All additions, deletions and modifications to the invention as disclosed herein which fall within the meaning and scope of the claims are to be embraced thereby.

4y

CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application is a continuation of U.S. patent application Ser. No. 10/365,648, filed Feb. 12, 2003, entitled, “Method and System for Improving a Text Search,” which is a divisional of U.S Pat. No. 6,691,107, filed Jul. 21, 2000, both of which are incorporated herein by reference in their entireties. FIELD OF THE INVENTION [0002] The present invention relates generally to text searching and more particularly to a method and system for improving text searching. BACKGROUND OF THE INVENTION [0003] The majority of text searching algorithms is based on analyzing the content of documents. Conventional text searching algorithms only evaluate each document individually in a type of competition to see which document makes the top of the list. For example, Yahoo.com searches within categories. Other web sites, such as AltaVista, etc., offer similar services. When a user asks a query, he/she is looking for a small set of documents that provide an answer. Text queries tend to provide large answer sets and a one-size-fits-all relevancy ranking. These text searching algorithms typically include extracting words or phrases, creating indexing structures, and determining discriminators for calculating relevance. When a user asks a text query, the index identifies the candidate documents, the relevance is calculated for each document, the candidate documents are ordered by relevance, and the resulting list is returned to the user. [0004] This is useful to a user when the list of candidate documents is relatively small. When the list becomes larger, other means of manipulating the list are needed. Why? Even though the relevance ranking tries to give a good order to the list, it may not be close to the criteria that user has in mind. Another source of imprecision is that a word submitted in a text query can have multiple meanings. A search for “jack” can yield results for card games, bowling, a children's game, fish, rabbits, etc. There are over 15 definitions of “jack” (http://www.dictionary.com/cgi-bin/dict.pl?term=jack). A large list requires refinement to factor out the candidate documents which do not match the user's criteria for selection. [0005] Accordingly, what is needed is a system and method for improving the text search for documents. The present invention addresses such a need. SUMMARY OF THE INVENTION [0006] A method and system for improving text searching is disclosed. The method and system provides a network of document relationship and utilizes the network of document relationships to identify the region of documents that can be used to satisfy a user's request. In a preferred embodiment, the text searching method in accordance with the present invention augments a conventional text search by using information on document relationships. The text searching method and system improves upon conventional text search techniques by incorporating relationship metadata to define regions to search within. In the present invention the definition of a region is not limited to just categories as it includes neighborhoods around individual documents and sets which have been user defined. BRIEF DESCRIPTION OF THE DRAWINGS [0007] FIG. 1 illustrates a hardware environment used to implement the present invention. [0008] FIG. 2 is a flow chart in accordance with the present invention. [0009] FIG. 3 illustrates the result of a search query. [0010] FIG. 4 illustrates the user identifying example candidates. [0011] FIG. 5 illustrates locating document related to the example candidates. [0012] FIG. 6 illustrates providing improved candidate documents. [0013] FIG. 7 illustrates selecting a location. [0014] FIG. 8 illustrates finding a plurality of entities relating to the location. [0015] FIG. 9 illustrates applying a search query to the members of the category. DETAILED DESCRIPTION [0016] The present invention relates generally to text searching and more particularly to a method and system for improving text searching. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements. Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein. [0017] The present invention is implemented in a computer or a computer network. In the preferred embodiment the present invention is implemented in a computer network, wherein client programs, also known as application programs, are not server-resident. Client programs are preferably external to the server so that they can operate on small size systems (e.g., personal computers, workstations, etc.). One of ordinary skill in the art will recognize that any client-server configuration may be used to implement the present invention, including a configuration wherein the client programs are resident in any computer including the server. [0018] Accordingly, FIG. 1 illustrates a hardware environment used to implement the present invention. As illustrated in FIG. 1 , in the preferred embodiment the present invention is implemented in a server computer (“server”) 100 . The server 100 generally includes, a processor 102 , a memory 104 such as a random access memory (RAM), a data storage device 106 (e.g., hard drive, floppy disk drive, CD-ROM disk drive, etc.), a data communication device 108 (e.g., modem, network interface device, etc.), a monitor 110 (e.g., CRT, LCD display, etc.), a pointing device 112 (e.g., a mouse, a track ball, a pad or any other device responsive to touch, etc.) and a keyboard 114 . It is envisioned that attached to the computer 100 may be other devices such as read only memory (ROM), a video card drive, printers, peripheral devices including local and wide area network interface devices, etc. One of ordinary skill in the art will recognize that any combination of the above system components may be used to configure the server 100 . [0019] The server 100 operates under the control of an operating system (“OS”) 116 , such as MVS™, AIX™, UNIX™, OS/2™, WINDOWS™, WINDOWS NT™, etc., which typically, is loaded into the memory 104 during the server 100 start-up (boot-up) sequence after power-on or reset. In operation, the OS 116 controls the execution by the server 100 of computer programs 118 , including server and/or client-server programs. Alternatively, a system and method in accordance with the present invention may be implemented with any one or all of the computer programs 118 embedded in the OS 116 itself without departing from the scope of the invention. Preferably, however, the client programs are separate from the server programs and are not resident on the server. [0020] The OS 116 and the computer programs 118 each comprise computer readable instructions which, in general, are tangibly embodied in or are readable from a media such as the memory 104 , the data storage device 106 and/or the data communications device 108 . When executed by the server 100 , the instructions cause the server 100 to perform the steps necessary to implement the present invention. Thus, the present invention may be implemented as a method, apparatus, or an article of manufacture (a computer-readable media or device) using programming and/or engineering techniques to produce software, hardware, firmware, or any combination thereof. [0021] The server 100 is typically used as a part of an information search and retrieval system capable of receiving, retrieving and/or dissemination information over the Internet, or any other network environment. One of ordinary skill in the art will recognize that this system may include more than one of server 100 . [0022] In the information search and retrieval system, such as a digital library system, a client program communicates with the server 100 by, inter alia, issuing to the server search requests and queries. The server 100 then responds by providing the requested information. The digital library system is typically implemented using a relational database management system software (RDBMS) 120 such as the DB2™ by IBM Corporation. The RDBMS 120 receives and responds to search and retrieval requests and termed queries from the client. In the preferred embodiment, the RDBMS 120 is server-resident. [0023] In the digital library system, such as IBM Content Manager by IBM Corporation, a library server (such as server 100 ) performs a library server program (“server program”) and an object server (such as server 100 ) performs an object server program (also “server program”). This dual-server digital library system is typically used as a large-scale information objects search and retrieval system which operates in conjunction with the RDBMS 120 . Large-scale information objects (“objects”) include a high resolution digital representation of ancient works of authorship and ancient works of art such as those found in the Vatican, as well as movies, classic and modern art collections, books, etc. [0024] The objects themselves are typically stored in a relational database connected to the object server, and the information about the objects is stored in a relational database connected to the library server, wherein the server program(s) operate in conjunction with the RDBMS 120 to first store the objects and then to retrieve the objects. One of ordinary skill in the art will recognize that the foregoing is an exemplary configuration of a system which embodies the present invention, and that other system configurations may be used without departing from the scope and spirit of the present invention. [0025] To take advantage of a system and method in accordance with the present invention, a connection server apparatus is necessary. A preferred embodiment of a connection server is disclosed in U.S. Pat. No. 5,687,367 entitled “Facility for the Storage and Management of Connection (Connection Server)” and assigned to the assignee of the present invention. The Connection Server is a general purpose, extensible facility, with accessible interfaces that can be included as a component in many systems. The Connection Server component is designed to provide a generic link management facility. The present invention creates a general-purpose facility for the storage and management of Connections that is tailorable, accessible, and tuneable for many purposes. Consumers of this service want to interact with this system with a minimum effort and be connected to associated objects with the least cost and time. [0026] The Connection Server provides very flexible structures for the identification of objects to be interconnected, the identification of the links which connect them, and the auxiliary information needed to materialize objects when they are referenced. [0027] The Connection Server is designed as a stand-alone reusable component. It interfaces with other independent components for services such as classification attributes, distributed database services, (object) storage, etc. Clean public programming interfaces are available for all components. It is independent from the “front-end”, the user driven display of the Connections and associated metadata. It is independent from any authoring facilities which may be used to customize the services, metadata, etc., that are provided. [0028] A system and method in accordance with the present invention provides for an improved text searching mechanism. FIG. 2 is a flow chart in accordance with the present invention. In this system a network of document relationships are provided, via step 202 . The document relationships are then utilized to define a region of documents that can be utilized to satisfy a user's request. Typically, the region is identified utilizing relationship metadata. [0029] The system and method in accordance with the present invention has two principal advantages. The first advantage of a system and method in accordance with the present invention is that a user can choose a small number of candidates from a large list returned from a query and use the chosen candidate(s) as an example of the type of information that is sought by the query. Based on this user feedback, an improved list of candidates can be generated which account for the text query submitted and the “regions” of documents identified by the user. This list can be generated by utilizing relationship metadata, for example, in a manner described in the copending patent application Ser. No. 09/620,756, now U.S. Pat. No. 6,611,845, entitled “Method and System for Storing and Managing Sets of Objects”, which is incorporated by reference herein. [0030] The second advantage of a system and method in accordance with the present invention is the ability to search within a “region”. Examples of regions are: (1) a category; (2) documents that neighbor a given document. A user can then specify a region and then ask a query to be performed in this region. This also reduces the number of candidates returned from the query. [0031] To more particularly describe the system and method in accordance with the present invention, refer now to the following description in conjunction with the accompanying drawings. [0032] First Advantage [0033] The first scenario demonstrates how the “first advantage” is achieved. In this embodiment, before a query can be processed, documents undergo preprocessing for indexing, relevance ranking, and relationship mining. The index, relevance, and relationship metadata is stored for use during a query. This scenario applies the search query followed by the application of relationship metadata to create an improved candidate list. [0034] FIG. 3 illustrates the result of an initial text search query. Each circle represents a document that can be returned by a text search query. After a query has been submitted against all of the documents, the search engine identifies the Original Candidate documents and orders them by relevance. In FIG. 3 , the circles that have been identified as 302 have been chosen as candidates by the search engine and returned to the user. [0035] FIG. 4 illustrates the user identifying example candidates. The user reviews some of the Original Candidate documents to determine examples of the type of document being sought. The user identifies at least one and preferably a smaller number than the original candidates Example Candidate documents to the system. The example candidate documents are labeled 304 in FIG. 4 . [0036] FIG. 5 illustrates locating documents related to the Example Candidates document by relationship metadata. The system locates documents that are related to the Example Candidate documents. Some of these documents may be Original Candidate documents; others may not. The relationships are shown as arrows 306 in FIG. 5 . As before mentioned, this element can be implemented utilizing the relationship metadata which is described, for example, in copending application Ser. No. 09/620,756, now U.S. Pat. No. 6,611,845, “Method and System for Storing and Managing Sets of Objects,” which is incorporated in its entirety herein. [0037] FIG. 6 illustrates providing a plurality of improved candidate documents. The system now knows which documents are Original Candidate documents, Example Candidate documents, and candidates by relationship. It calculates the new order of presentation by considering the document's relevance ranking, the number of relationships it participates in, and whether it was an Original Candidate document. The new list contains a smaller number of Improved Candidate documents illustrated by circles 308 . [0038] Second Advantage [0039] The second scenario demonstrates how the “second advantage” is achieved. This scenario applies the definition of a “region” using relationship metadata, followed by the search query. [0040] FIG. 7 illustrates selecting a location. A location is selected within the information space. This location can be a category designation, an actual document, or another placeholder in the information space. In this scenario, the circle 402 represents a chosen Category. [0041] FIG. 8 illustrates finding a plurality of entities relating to the location utilizing relationship metadata. This is also performed utilizing the above-identified copending application. For example, from a given Category, all of the Category Members are found by the system. If the scenario had chosen a document rather than a category, related documents would have been found by the system. In general, this step creates a “region” from the relationship metadata. The circles 404 represent the members of the category that form the region to be searched. [0042] FIG. 9 illustrates applying a search query to the members of the category. The search query is then applied to all members of the region to locate all of the Candidate documents that satisfy the query. The Improved Candidate list is returned to the user. The circles 406 represent the documents that satisfy the search query and are members of the region. [0043] In a method and system in accordance with the present invention, a network of document relationships are utilized to identify the “region” of documents that can be used to satisfy a user's request. There are two advantages of utilizing text searching and relationship metadata. The first is gained by performing the search, then utilizing the relationship metadata. The second is gained by utilizing the relationship metadata, then performing the search. In so doing, a significantly smaller list is obtained via the system than when utilizing conventional text searching algorithms. [0044] Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to the field of power tools and, more particularly, to a collet lock arrangement for a power tool of the type receiving interchangeable accessory tools. 2. Description of the Prior Art Various types of rotating power machinery, particularly with regard to certain types of hand-held power tools, require a user to selectively attach an accessory tool thereto such as a drill-bit or a surface treating disk (for example, a polishing pad, a sanding disk, or a grinder tool). Convenient removal and replacement of interchangeable accessory tools is therefore desirable. A selected accessory tool attaches to an end of a rotatable collet shaft which is mechanically driven by power transmitting components within the power tool. Conventionally, a collet lock is often used to lock the collet shaft against movement during removal and replacement of an accessory tool. In many portable power tools, including air tools and electric motor-driven tools, a nut is provided to axially secure the accessory tool to the rotatable shaft. When changing accessory tools, the nut must be loosened to allow the shaft to release its grip on the accessory tool. Similarly, when a new accessory tool is added, the nut is tightened (preferably with a wrench or the like) within or about the shaft so as to be rotatably axially driven thereby. During a removal and/or replacement operation, the collet shaft must be prevented from rotating or else it would be impossible to loosen a tightened nut if the latter is free to rotate freely with the shaft to which it is secured. During loosening of the nut, an operator connects a first wrench to the secured nut and a second wrench to a wrenching portion along the rotatable shaft. A torque is then applied to the nut by rotating the first wrench in a counter-clockwise direction causing the nut to disengage from the rigidly held rotatable shaft. In the case of portable power tools of substantial weight, the two handed operation described above is a great inconvenience and dangerous. For example, because the operator's two hands are both being put to use in holding the two wrenches, when changing an accessory tool the operator can easily lose his grip on the tool causing the device to fall on the ground or, alternatively, will be unable to create a strong enough torque about the rotatable shaft since the bulk of the torque is unstably counteracted by the great weight of the housing portion of the power tool to which an end of the collet shaft is mechanically connected. As a result, the two-handed operation described above becomes a three-handed operation, particularly for large, heavy power tools as the operator inevitably is forced to secure the base or housing portion of the power tool in a vise (the third hand) to facilitate the unscrewing of the nut at an opposite end therefrom. Alternative constructions for securing the accessory tool to the collet shaft other than with a secured nut are also well known. One such construction is a keyless chuck design. While a three-handed operation is unnecessary, a big disadvantage of the keyless chuck is that its use is limited to relatively light-weight portable tools (such as drills which receive interchangeable driver bits) whose mass and shaft rotational speed is small. Portable tools such as die grinder tools characteristically have a high rotational speed (≈20,000 RPM) and are subject to high vibrations. Inevitably therefore, a keyless chuck therewith would become loose over time causing the die grinder bit to fall out or break during use. SUMMARY OF THE INVENTION It is a general object of the invention to provide a hand-held power tool with a collet locking structure which is economical and easy to manufacture. It is another object of the present invention to provide a hand-held power tool with a collet locking structure which allows a user to conveniently remove or replace an interchangeable accessory tool. Because the collet locking structure operates to lock the shaft against rotation in the locked position, the user is saved the inconvenience of having to use a third hand (or a vise) to secure the tool's housing from rotation relative to the shaft. For the same reason, also rendered unnecessary is the use of a second wrench. It is another object of the invention to provide a collet locking structure which locks shaft rotation relative to a hand-held power tool's housing to make possible manual use of the power tool. It is another object of the invention to provide a collet locking structure which uses a locking sleeve made of a flexible material to lock the shaft against rotation. In the event the locking sleeve is damaged or worn out, a replacement sleeve can be readily substituted. These and other features of the invention are attained by providing a hand-held power tool with a collet lock arrangement which collet lock arrangement includes a powered rotatable shaft having a base portion and a distal end portion defining a collet for adaptably connecting a driver tool attachment thereto. Also included is a locking structure for securely locking the shaft to the power tool's housing to selectively prevent the shaft from rotating when in a locked position while allowing the shaft to freely rotate in an unlocked position. The locking structure is provided with a locking sleeve which is coaxially coupled around the shaft for axial movement relative thereto between the locked and unlocked positions. The locking structure also includes a clamp nut fixedly connected to the housing and a sleeve guide non-rotatably coupling the locking sleeve to the clamp nut. The clamp nut and the guide are both provided with an opening for coaxially receiving therethrough the shaft and the locking sleeve. During axial movement of the sleeve from the unlocked position to the locked position, a portion of the sleeve is slidably matingly engaged between the base portion of the shaft and the guide to lock the shaft against rotational movement. It is envisioned that this collet locking arrangement may be implemented on an air-driven power tool, although there is no reason why it may not also have application in an electrically-driven power tool. The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS For the purpose of facilitating an understanding of the invention, there is illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages should be readily understood and appreciated. FIG. 1 is a partial side elevation view of a collet locking arrangement of a hand-held power tool constructed in accordance with and embodying the features of the present invention, shown with a locking sleeve set in the unlocked position. FIG. 2 is a view similar to FIG. 1, but shown with the locking sleeve set in the locked position. FIG. 3 is an enlarged perspective, exploded view of the collet locking arrangement of FIG. 1; FIG. 4 is an enlarged horizontal sectional view taken generally along the line 4--4 in FIG. 3. FIG. 5 is an enlarged view in horizontal section taken along the line 5--5 in FIG. 3; FIG. 6 is an enlarged vertical sectional view taken generally along the line 6--6 in FIG. 3. FIG. 7 is an enlarged horizontal sectional view taken generally along the line 7--7 in FIG. 3. FIG. 8 is an enlarged view in partial vertical section of the collet looking arrangement of FIG. 1 with the unlocked position shown on the left side of and the locked position shown on the right side of the longitudinal midplane; and FIG. 9 is a horizontal sectional view taken generally along the line 9--9 in FIG. 8, with the parts shown in the locked position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 and 2, there is illustrated an upper portion of a hand-held power tool, generally designated by the numeral 10 and including a housing portion 20 and a collet lock arrangement 30, the latter being constructed in accordance with and embodying the features of the present invention. Housing portion 20 includes an endplate 21, a bearing 22 and a seal 23, all matingly engaged within a cylindrical, partially-threaded, housing wall 24 and cooperating therewith to support a rotor shaft 25. The outer surface of housing wall 24 includes housing threads 26. The construction and operation of motor shaft elements 21-26 are well known in the art of air tools and are shown here only for illustrative purposes to aid in understanding the operation of collet lock arrangement 30 of the present invention. The collet lock arrangement 30 is of a four-part construction as shown more clearly by the exploded view in FIG. 3 to be described below. Collet lock arrangement 30 includes a locking sleeve 40, a clamp nut 60, a sleeve guide 80 and a rotatable shaft 100. The four elements recited above cooperate with each other and with housing portion 20 to provide a user of power tool 10 with the ability to set locking sleeve 40 in one of two positions, namely, the unlocked position of FIG. 1, for unlocking the shaft 100 and the locked position of FIG. 2 for locking the shaft 100 against rotation. Referring now also to FIGS. 4 and 5, the locking sleeve 40 has a substantially cylindrical hollow shape and is characterized by locking sleeve ends 41, 42 and mid-portion 43. More specifically, locking sleeve end 41 is a cylindrical body having a plurality of serrations 44 of fixed depth extending circumferentially around the outer surface thereof. An inner surface of locking sleeve end 41 defines a fixed-diameter cylindrical bore 45 extending the whole axial length thereof. Locking sleeve end 42 is a substantially square-shaped body defined by internal flat surfaces 46 separated by internal arcuate wall surfaces 47 and external flat surfaces 48 separated by external arcuate wall surfaces 49. Opposed ones of the inner surfaces 46 of the locking sleeve end 42 are spaced apart at least the diameter of the cylindrical bore 45 of locking sleeve end 41. A cross-section of locking sleeve end 42 is shown in FIG. 4. The mid-portion 43 separates locking sleeve ends 41 and 42 and is substantially cylindrical-shaped. Longitudinal slots 50 cooperate with circumferential slots 51 to divide mid-portion 43 into two vertical and diametrically opposed rounded columns 52-53 extending axially between ends 41 and 42, as well as into two flexible walls 54 and 55, also diametrically opposed and integrally axially extending from locking sleeve end 42, the flexibility of which will be explained below. Flexible walls 54, 55, slots 50, 51 and columns 52, 53 cooperate to define an inner cylindrical bore 56 of equal diameter to that of cylindrical bore 45 of locking sleeve end 41. Flexible walls 54 and 55 include two axially spaced-apart grooves 57 and 58 of fixed depth extending circumferentially about the outer surface thereof. A rounded non-grooved surface region 59 separates grooves 57 and 58. Clamp nut 60, shown in perspective view in FIG. 3, is of a one-piece, partially dome-shaped construction consisting of a first internally threaded portion 61 and a non-threaded portion 62 separated by a first annular rim 63. Non-threaded portion 62 includes, at an end opposite first annular rim 63, a second annular rim 64 which defines an annular inner surface 65 dimensioned to be received by circular grooves 57 and 58 on flexible walls 54 and 55, as shown in FIG. 8. Clamp nut 60 is open at both ends to form a hollow cavity therein. Threaded portion 61, shown also more clearly in the breakaway portion of FIG. 8, includes, along an inner diameter thereof, clamp nut threads 66 extending longitudinally from below an inner wall surface 67 of first annular rim 63 to a corner portion 68. Along the outer rounded surface of threaded portion 61 there are provided flats 70, circumferentially arranged a fixed distance apart specifically provided to act as gripping surfaces and dimensioned to optionally receive either a user's fingertips or a wrench tool. Referring also to FIG. 6, the sleeve guide 80 consists of a substantially cylindrical body 81 having at a base end thereof an annular flange 82 extending radially outwardly along an outer circumference of body 81. A substantially square-shaped projection 83 extends radially outwardly from annular flange 82. Body 81 is open at both ends. The inner walls of body 81 are dimensioned to engage with the outer wall of the substantially-square shaped body of locking sleeve end 42 and consist of longitudinally extending flat surfaces 84 separated by arcuate wall surfaces 85. Beveled surfaces 87 extend from a top base end 88 of body 81 to the top most edge of flat surfaces 84 forming part-conical surfaces. An annular groove 89 of fixed depth is formed at a base end surface 90 of body 81. Referring also to FIG. 7, rotatable shaft 100 includes a base portion 101, a cylindrical body portion 102, a wrench gripping portion 103 and a collet portion 104. Base portion 101 is substantially square-shaped and formed by flat walls 105 and arcuate walls 106 and dimensioned to engage the respective internal flat surfaces 46 and internal arcuate surfaces 47 of locking sleeve end 42. Cylindrical body portion 102 extends longitudinally from top surface 107 of base portion 101. Wrench gripping portion 103 extends longitudinally from body portion 102 and consists of a cylindrical body 108, and a frustoconical portion 109. Flat surfaces 110 and 111 are formed at diametrically opposed locations on the gripping portion 103 to provide gripping surfaces for an appropriately sized wrench tool. Collet portion 104 consists of four longitudinally extending arcuate jaw portions 112 arranged circumferentially but spaced a fixed distance apart. Each jaw portion 112 is connected at a base end thereof to the top surface of wrench gripping portion 103. Each jaw portion includes an angled smooth surface portion 113 and a ridged bottom portion 114. The ridged portions 114 cooperate to provide a threaded post around which a nut 130 is engaged to cause the collet portion 104 to flex inwardly around an interchangeable accessory tool (not shown), the latter having a shaft dimensioned to fit within opening 115 formed by the cooperative relationship of jaw portions 112, all in a known manner. With the exception of locking sleeve 40, for which a super tough nylon or like material is preferred, all other components may be constructed from metal or like material formed into the shape generally shown in the drawings. It will be appreciated that because of the nylon material of the locking sleeve 40, the walls 54 and 55 resulting from the slots 50 and 51 are flexible and resilient. This facilitates movement of the locking sleeve 40 between its locked and unlocked positions, as explained below. During initial assembly, rotatable shaft 100 is matingly engaged with the rotor shaft 25 so that a base surface 116 of rotatable shaft 100 rests squarely on the surface of bearing 22 and partially extends within wall 24 of housing portion 20. Conical washers 131, 132 are seated over endplate 21 in overlapping fashion. Threads 26 of housing wall 24, shown in cutout view in FIG. 8, allow the clamp nut 60 to be threaded (screwed) thereon by way of clamp nut threads 66. First, however, prior to threading engagement of clamp nut 60 and housing wall 24, locking sleeve 40 is separately brought into engagement with the inner walls of sleeve guide 80. Once locking sleeve 40 is so engaged, locking sleeve 40 and sleeve guide 80 are inserted in combination into clamp nut 60 by inserting this combination through the large opening end of clamp nut 60. Once properly engaged, circular groove 57 located on flexible walls 54 and 55 will mate with annular inner surface 65 of non-threaded portion 62 of clamp nut 60, in which position, the top surface areas of annular flange 82 and projection 83 of sleeve guide 80 are brought into contact with the bottom inner wall surface of first annular rim 63 of clamp nut 60. Projection 83 of sleeve guide 80 is engaged with an opening 27, shown more clearly in FIG. 9, formed in wall 24 of housing portion 20, to restrain rotation of sleeve guide 80 relative to housing portion 20. Thereafter, the combination of locking sleeve 40, clamp nut 60 and sleeve guide 80 are brought into engagement with rotatable shaft 100 and housing portion 20. To do this, the rotatable shaft 100 is inserted into the cylindrical cavity of locking sleeve 40 at the same time clamp nut 60 is engaged with housing portion 20 by tightening (threading) of threaded portion 61 around threads 26 of housing wall 24, and base end surface 90 of sleeve guide 80 is brought into contact with conical washer 132. A tight fit is assured between housing portion components and the collet lock arrangement due to the axially flexing nature of conical washers 131 and 132 and the securely threaded coupling of the clamp nut 60 to the housing wall 24. Once the power tool 10 is assembled as described above, locking sleeve 40 will reside in one of two possible positions. One such position is shown in FIG. 1 and corresponds to the unlocked position. Referring to the left half of FIG. 8, there is shown the position of locking sleeve 40 relative to clamp nut 60; the latter shown cross-sectionally. Clamp nut 60, locking sleeve 40 and sleeve guide 80 are all coaxially arranged about rotatable shaft 100. Rotatable shaft 100 is connected directly to the drive motor (not shown) of the power tool 10 via rotor shaft 25. In the unlocked position, the rotatable shaft 100 rotates freely within locking sleeve 40 with respect to both the clockwise and counterclockwise directions. As shown, a portion of locking sleeve end 42 rests securely a distance within sleeve guide 80. The remaining portion of locking sleeve end 42 rests above sleeve guide 80 below second annular rim 64 of clamp nut 60. The locking sleeve 40 is restrained in place by the mating engagement of annular inner surface 65 of second annular rim 64 with the circular groove 57 in flexible walls 54 and 55, this engagement inhibiting axial movement of sleeve 40 and maintains same in the unlocked position, at least until a sufficient disengaging force is applied thereto. As should be readily apparent, because the locking sleeve 40--and more particularly, substantially square-shaped locking sleeve end 42--is not engaged with base portion 101 of rotatable shaft 100 in the unlocked position, locking sleeve 40 does not disturb the normal operation and rotation of the rotatable shaft 100. The rotatable shaft 100 thus rotates freely in both radial directions and locking sleeve 40 is non-functional in the unlocked position. To engage locking sleeve 40 in the locked position of FIG. 2, the power tool user grasps the portion of locking sleeve end 41 which includes serrations 44 and axially applies a pressure thereon to cause locking sleeve 40 to slide downwardly through sleeve guide 80 toward base portion 101. The flexibility of the walls 54 and 55 of the locking sleeve 40 permits them to be deflected inwardly by the camming action of the surface 65 of the clamp nut 60, thereby facilitating disengagement of the surface 65 from the groove 57 to permit the locking sleeve 40 to be axially moved to its locked position. This locked position of the locking sleeve 40 will now be described in greater detail by reference to the right-half view of FIG. 8 and the cross-sectional view of FIG. 9. During axial movement of locking sleeve 40 from the unlocked position to the locked position, substantially square-shaped locking sleeve end 42 is brought into mating engagement with the base portion 101 of rotatable shaft 100. During axial movement, the downward axial force applied by the user causes the flexible walls 54, 55 to flex inwardly just enough so that the annular inner surface 65 of clamp nut 60 begins to ride (cam) over the rounded non-grooved surface region 59 separating grooves 57 and 58. As annular inner surface 65 approaches groove 58, sleeve guide 80 causes the substantially square-shaped locking sleeve end 42 --which is coaxially arranged between sleeve guide 80 and rotatable shaft 100--to be brought into mating alignment with base portion 101 of rotatable shaft 100. When annular inner surface 65 engages groove 58 on flexible walls 54, 55, this will serve as an indication to the user that the locking sleeve 40 is now in the locked position and that the rotatable shaft 100 is secured against rotational movement. The engagement of groove 58 with surface 65 inhibits axial movement of sleeve 40 and restrains the sleeve 40 in the locked position, at least until a sufficient disengaging force is applied thereto, which would cause the shaft 100 to unlock and thus rotate freely. Referring to FIG. 9, it should be appreciated that when the locking sleeve 40 is set into the locked position, inner surfaces 46, 47 of locking sleeve end 42 are dimensioned to matingly couple around walls 105, 106, respectively of base portion 101 of rotatable shaft 100 which is powered by rotor shaft 25. Similarly, external surfaces 48, 49 of locking sleeve end 42 are dimensioned to matingly engage with inner surfaces 84, 85 of sleeve guide 80. Given that sleeve guide 80 is restrained against rotation by the engagement of projection 83 and opening 27 of housing portion 20, clamp nut 60, sleeve guide 80 and locking sleeve 40 cooperate to coaxially matingly engage around rotatable shaft 100 and prevent its rotation. Once the rotatable shaft 100 is locked against rotation by the locking sleeve 40, a power tool user can safely and easily remove the interchangeable accessory tool (not shown) locked by nut 130 in opening 115 which is defined by jaw portions 112. To do this, the user need only hold the housing portion 20 and/or clamp nut 60 of power tool 10 in one hand while using the other `free` hand to rotate nut 130 in the counterclockwise (or loosening) direction which will ultimately allow jaw portions 112 to release their grip on the shaft of the interchangeable accessory tool. Of course, if the nut is too tight, the user can instead use a wrench tool, applied by his free hand to facilitate loosening of the nut 130. Since the rotatable shaft 100 is locked against rotation by coupling it to the housing portion 20 by the cooperation of the clamp nut 60, sleeve guide 80 and locking sleeve 40 therewith, a third hand (such as a vise) is not necessary to prevent rotation of shaft 100 relative to the power tool's housing portion 20. In the preferred embodiment, the power tool 10 has been described as an air tool, however, it should be readily apparent that the present invention is equally applicable to other types of power tools, including electrically driven power tools. While the power transmitting components of other power tools may differ, the collet lock arrangement 30 described above in connection with the preferred embodiment can easily be modified to be incorporated into such other types of power tools. It is also envisioned that the collet lock arrangement can be used with collet designs that may be different from the jaw portions 112 and nut 130 combination in the preferred embodiment. It is also envisioned that while the mating engagement of the sleeve guide 80, locking sleeve 40 and base portion 101 of rotatable shaft 100 has been accomplished by providing a substantially square-shaped polygonal arrangement, any type of polygonal arrangement which achieves the same result is equally applicable. Similarly, while the locking sleeve 40 of the presently preferred embodiment is described as comprising three integral sections, namely, locking sleeve ends 41, 42 and mid-portion 43, any coaxially coupled locking sleeve which locks the rotatable shaft of a power tool 10 by axial movement relative thereto is considered an equivalent to the preferred embodiment. It should also be readily apparent that whatever interchangeable accessory tool (not shown) is to be used with the power tool 10 of the present invention, once the rotatable shaft 100 is locked against rotation by the engagement of locking sleeve 40 therewith, the power tool can be used manually as a screw driver, with a suitable bit, to facilitate tightening of a screw element by the accessory tool to a specific tactile torque level, or alternatively, to facilitate an initial loosening of the screw element. The simple construction of the collet lock arrangement 30 of the present invention will inevitably result in economical production with the ultimate effect of low retail costs per unit. Additionally, because accessory tools can be more readily interchanged using only two hands, productive use of the power tool is greatly increased. Similarly, risk of injury by users who attempt to remove an accessory tool coupled to a non-lockable rotatable shaft and who do not have a `third` hand and thus occasionally drop the power tool causing injury to themselves and/or to the tool itself, is greatly reduced. Finally, because the locking sleeve 40 is of such construction as to make removal thereof possible, a user can conveniently replace a damaged or deformed locking sleeve with very little difficulty. While particular embodiments of the present invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.

4y

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a division of copending Application No. 09/340,058, filed Jun. 28, 1999. [0002] This application claims the priority of German Patent Application No. 198 28 589.2 filed Jun. 26, 1998, the subject matter of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0003] This invention relates to band saw machine which includes a workpiece table for supporting a workpiece advanced thereon in a feed direction; a saw band for severing the workpiece in a cutting plane on the workpiece table in consecutive sawing steps; a saw band support for swinging the saw band out of the cutting plane after each sawing step, for swinging the saw band into the cutting plane before each sawing step and for maintaining the saw band in the cutting plane during each sawing step; openable and closable cooperating clamping jaws disposed downstream of the cutting plane as viewed in the feed direction for clamping the workpiece undergoing sawing the saw band; and openable and closable cooperating feed jaws for advancing the workpiece toward the cutting plane in the feed direction. The feed jaws which are disposed upstream of the cutting plane, are, in sequence, openable after closing the clamping jaws and before termination of a cutting step, shiftable away from the cutting plane to an extent of a successive work piece feed and closable on the workpiece for moving the workpiece against the feed direction away from the cutting plane after the sawing step. [0004] Examples of band saw machines of the aforementioned type include both so-called horizontal band saws, including those having a pivotable upper part, and so-called vertical band saws. These saws serve in sectioning a metallic workpiece material that is typically present in the form of individual metal rods or bundles of metal rods, but can also be in another form that is suitable for processing on such band saw machines. [0005] The workpiece material is conveyed to the cutting region of the band saw machine, in which it lies on a workpiece table, by way of a conveyor track disposed upstream of the workpiece table. The separated sections are cleared on the side of the cutting plane opposite the conveyor track by advancing the previously separated section, with the advance of the workpiece material, by the amount of the section to be separated next. [0006] In band saw machines of the discussed type, the workpiece material is held for the cutting cycle by a pair of clamping jaws that open and close transversely to the direction of material feed, but are immovable in the direction of material feed; the jaws can be disposed behind the cutting plane, in relation to the feed direction of the workpiece material. The material feed is effected by a pair of opening and closing clamping jaws which are disposed on the supply side of the material and which are displaceable in the direction of material feed. [0007] As mentioned at the outset, in the described metal band saw machines, the saw band circulating endlessly over two running wheels is guided by saw-band guides in the cutting region next to the workpiece material, and pivoted into the cutting plane, which extends in a different direction from the circulation plane of the saw band, to assure an endless supply and removal of the workpiece material. The saw-band guides, which are advisably positioned as close as possible next to the workpiece material, generally have hard-metal sliding parts on both side of the saw band and, perpendicular to these parts, hard-metal sliding parts or running rollers against the rear of the saw band. One of the two lateral band guides is usually fixedly mounted to the associated guide arm, while the opposite band guide is either set at a fixed distance with respect to the first lateral band guide, or is pressed against the saw band by means of a spring force or a hydraulic force for guiding the saw band with as little play as possible between the two lateral band guides. [0008] When a cutting cycle is complete, the cutting run of the saw band must be moved backward through the cutting gap again to effect the return stroke. This causes the lateral cutting edges of the saw band teeth to slide along the workpiece material; at high band speeds, the teeth are subjected to considerable wear. Moreover, when material bundles are cut, the danger always exists that the rear of the saw band will be caught on a piece of material that protrudes slightly or changes its position. Therefore, the guide arms are often equipped with sensing elements that detect the sliding of the saw band out of the band guides for avoiding severe damage to the saw band. [0009] To remedy the above-described problems, it is already known to space the workpiece material from the cutting plane, or to move it away from the cutting plane on the supply side thereof, after the cutting cycle has ended. The material is spaced by the clamping jaws that are movable in the direction of material feed. [0010] The spacing of the material on the supply side of the cutting plane permits the cutting run of the saw band to be free from workpiece material on at least one side during the saw-band return stroke, so it can evade edges that may be protruding, thereby reducing the wear of the side edges of the saw-band teeth. In connection with hard-metal blades, which are frequently soldered to the teeth of the saw band in contemporary machines, however, this measure is no longer sufficient. Rather, a contactless return stroke of the saw band is becoming increasingly significant. [0011] A contactless saw-band return stroke could be attained through the spacing of the workpiece material from both sides of the cutting plane following the cutting cycle. This, however, would mean that the clamping jaw pair which is immovable in the feed direction of the workpiece material and which is disposed behind the cutting plane, would have to be adjustable in the material-feed direction, which would require a considerable structural outlay and more space. SUMMARY OF THE INVENTION [0012] It is therefore an object of the invention to improve the apparatus of the type mentioned at the outset such that, following the cutting cycle, the return movement of the saw band is effected in a simple, space-saving and cost-effective manner, free from any contact with the workpiece material. [0013] Regarding the apparatus mentioned at the outset, the object is accomplished according to the invention in that, for the return stroke of the saw band, the saw band support can be shifted away from the cutting plane, perpendicularly to the cutting plane, and in the direction of the spaced workpiece material. The effect of these measures is that, starting from a one-sided spacing of the workpiece material from the cutting plane, as is the case following the cutting cycle, the saw band is freed from the workpiece material on both sides because it is adjusted in the direction of the material spacing. Of course, in all of the embodiments of the invention, the magnitude of the adjustment of the cutting run of the saw band is dimensioned smaller than the control variable for the spacing of the workpiece material from the cutting plane. The saw band can, however, be adjusted without additional space requirements and with comparatively simple means. It is apparent that only a slight, simple adjustment to the saw-band guides is required to attain the effect sought with the invention. The adjustment of one of the two saw-band guides is basically sufficient, because the associated inclined position of the saw band suffices to free the band from the workpiece material. Of course, both guides can also be adjustable to keep the magnitude of the setting movement of the individual guides small. This measure of the invention does not necessitate additional space, because the saw-band guides are completely free in the relevant direction anyway. [0014] According to a first solution involving an apparatus in which the saw band moves between hard-metal sliding parts inside the guides, it is provided in accordance with the invention that the hard-metal sliding parts are disposed at a respective end of setting means seated in the guides, and the setting means can be adjusted equidistantly between stops. Hydraulically- or pneumatically-actuatable cylinder-piston assemblies can be provided as setting means. In this way, the sliding guides for the saw band are merely shifted away from the cutting plane by a small amount—0.5 mm to 1.0 mm suffice—prior to the return-stroke motion of the saw band; to this end, the cylinder-piston assemblies are correspondingly actuated with the aid of the automatic control of the band saw machine. After the return stroke of the saw band has been completed, the cylinder-piston assemblies are actuated in the reverse order for guiding the saw band in the cutting plane for the next cutting cycle. [0015] According to a different design, in which at least one of the guides is adjustable, together with the guide arm supporting it, in essentially the direction of motion of the cutting run of the saw band on a guide track of the stand of the band saw machine, in the solution offered by the invention, the adjustable guide arm can be acted upon by a force acting in the direction of the spaced workpiece material, and the guide arm can be pivoted by this force for the return stroke of the saw band. A conceivable modification of this concept involves the continuous action of the force on the guide arm, and the option of increasing the guide play of the guide arm for the return stroke of the saw band. [0016] The effect of these measures is that, due to the increase in the guide play of the movable guide arm, the guide arm has a certain freedom of motion with respect to its guide track, and is tipped somewhat within the guide track due to the effect of the aforementioned force, resulting in the adjustment of the saw band guide, and thus of the saw band, according to the invention. Of course, the means for changing the guide play can be turned on and off automatically by the process control of the band saw machine such that the guide arm is connected to its guide track with as little play as possible for the respective cutting cycle, and the guide play is increased for the return stroke of the saw band. [0017] If, in the design described above, the workpiece material is held next to the cutting plane during the cutting process by a pair of clamping jaws that open and close parallel to the cutting plane through the movement of at least one of the clamping jaws, but are immovable in the direction perpendicular to the cutting plane, and the movable clamping jaw and the adjustable guide arm are associated with one another, it can be provided that the movable clamping jaw at least indirectly forms the abutment for the force acting on the guide arm. The background for this is that the movable clamping jaw and the adjustable guide arm are coupled to one another here for adjusting the mutual spacing of the two band-guide arms to the cross section of the workpiece material to be processed, the cross section being reflected equally in the work position of the movable clamping jaw. [0018] The force acting on the adjustable guide arm can be a spring force that is preferably effected by a compression spring. BRIEF DESCRIPTION OF THE DRAWINGS [0019] [0019]FIG. 1 is a front view of a band saw machine. [0020] [0020] 20 FIG. 2 is a plan view of the band saw machine according to FIG. 1. [0021] [0021]FIG. 3 is a detailed view of the saw-band guide in the work region. [0022] [0022]FIG. 4 is a schematic representation of the work sequence in the cutting region of the band saw. [0023] [0023]FIG. 5 is a side view of the adjustable guide arm according to FIGS. 1 through 3, partly in section. [0024] [0024]FIG. 6 is a sectional view of the lower end of the guide arm, which guides the saw band, according to FIG. 5. [0025] [0025]FIGS. 7 and 8 are the sectional view VII-VII from FIG. 6, in two work positions. [0026] [0026]FIG. 9 is a side view of the movable guide arm according to FIGS. 1 through 3, in a different design, and partly in section. [0027] [0027]FIG. 10 is a sectional view of the lower, guiding end of the guide arm according to FIG. 9. DETAILED DESCRIPTION OF THE INVENTION [0028] As can be seen from FIGS. 1 and 2, the band saw machine illustrated therein has a machine stand 1 , with respect to which an upper saw part 2 can be displaced vertically by way of guide columns 3 , 4 . [0029] The machine stand 1 has a workpiece table 5 for supporting the workpiece material, not shown; a supply track formed from rollers 6 is disposed upstream of this table, and supplies the workpiece material to the work region of the band saw machine in the direction of the arrow 7 . The upper edge 8 of the rollers 6 lies in the same plane as the surface of the workpiece table 5 . [0030] A saw band 9 circulates endlessly via deflection wheels 10 , 11 in the upper saw part 2 ; in the present case, the deflection wheel 11 is driven to rotate counterclockwise. In the illustrated embodiment, the axes of rotation of the deflection wheels 10 , 11 are oriented perpendicular to the representation according to FIG. 1, or parallel to the drawing plane of FIG. 2, respectively, so the saw band 9 correspondingly circulates, on the deflection wheels, perpendicular to the drawing plane of FIG. 1, or parallel to the drawing plane of FIG. 2, respectively. Deflection guides, which will be described in detail below and are supported by the lower, free ends of guide arms 12 , 13 disposed at the upper saw part serve in pivoting the saw band, which is presently located in the cutting region above the workpiece table 5 , into a position perpendicular to the surface of the workpiece table 5 . These guides thus effect the downward orientation, with respect to FIG. 1, of the cutting edge 14 of the saw band 9 between the guide arms 12 , 13 toward the workpiece material, not shown. The cutting plane 15 formed by this arrangement extends perpendicular to the surface of the workpiece table 5 , and is shown in a dot-dash line in FIG. 2, which also shows a simplified representation of the aforementioned saw-band guides 16 , 17 . [0031] In the present case, during the cutting cycle, the workpiece material is held by clamping jaws 18 , 19 , which are disposed as close as possible behind the cutting plane 15 , with respect to the material-feed direction indicated by the arrow 7 . The clamping jaw 19 is fixedly connected to the machine stand 1 , while the clamping jaw 18 can open and close in the direction of the double-headed arrow 20 . [0032] With respect to the material-feed direction represented by the arrow 7 , feed clamping jaws 21 , 22 are further disposed on the machine stand 1 in front of the cutting plane 15 ; these jaws can be pushed back and forth together on the machine stand 1 , parallel to the feed direction, in the manner indicated by the double-headed arrow 23 . Furthermore, of these jaws, the feed jaw 21 can be displaced with respect to the clamping jaw 22 , in the manner indicated by the double-headed arrow 24 , for moving the pair of clamping jaws 21 , 22 from the open position into the closed position, or vice versa. [0033] The function of the band saw machine described to this point can be summed up as follows: The workpiece material lying on the rollers 6 is gripped through the closing of the feed jaws 21 , 22 in the direction of the arrow 24 , and is advanced by the movement of the jaws in the direction of the arrow 7 or 23 until it passes through the cutting plane 15 by the size of the material piece to be separated. The material piece to be cut off is gripped by the clamping jaws 18 , 19 and held securely for the cutting cycle, which is effected while the saw band is running in that the upper saw part 2 is moved downward with respect to FIG. 1. [0034] During the sawing cycle, the feed jaws 21 , 22 can be opened and moved back, counter to the arrow direction 7 , by the size of the workpiece material to be separated next in order to clamp the workpiece again prior to the end of the cutting cycle. [0035] After completion of the cutting cycle, that is, when the cutting edge 14 of the saw band 9 has reached the surface of the workpiece table 5 , the feed jaws 21 , 22 draw the workpiece material they are holding back over a short distance, counter to the direction of the arrow 7 , in order to make space for the saw band 9 for the return stroke, which is effected by the return of the upper saw part 2 into the upper position visible in FIG. 1. The feed jaws 21 , 22 now advance the workpiece material again by the amount of the material piece to be separated next, and the described cycle begins again. [0036] [0036]FIG. 3 shows the band-guiding arms 12 , 13 in detail; it is apparent that the band-guide arm 13 is fixedly connected to a guide track 25 disposed on the upper saw part 2 , while the guide arm 12 is displaceable on this guide track 25 in the direction of the double-headed arrow 26 . The latter serves in adapting the mutual spacing of the guide arms 12 , 13 , and the saw-band guides 16 , 17 supported thereon, to different workpiece cross sections, so the saw-band guides 16 , 17 are always positioned as closely as possible next to the workpiece material. To make the adjustment of the mutual spacing of the guide arms 12 , 13 independently, the adjustable guide arm 12 is movably connected to the movable clamping jaw 18 in a manner known per se, and is therefore not shown and described in detail, so the guide arm always follows the position of this clamping jaw, which, after all, always assumes a position that corresponds to the workpiece cross section for the clamping position associated with the cutting cycle. [0037] Corresponding to the circulating direction of the saw band 9 , as mentioned above in connection with FIG. 1, the cutting run of the saw band 9 visible from FIG. 3 runs from left to right, with respect to FIG. 3, so the saw band is pivoted into the cutting plane by the saw-band guide 16 . To facilitate this process, a guide roller 27 is disposed upstream of the band guide 16 . [0038] As mentioned in the description of the band saw machine and its function, the workpiece material is spaced slightly from the cutting plane 15 at the end of the cutting cycle through the effect of the feed jaws 21 , 22 in order to make more space for the return stroke of the saw band. The separated workpiece segment is, however, still held by the clamping jaws 18 , 19 , so its cut surface is positioned directly against the cutting plane 15 , and the saw band thereby grinds against the cut surface during the return stroke. To prevent this, according to the invention, the saw band is displaced slightly out of the cutting plane, in the direction of the spaced workpiece material, for the return stroke. This procedure is apparent from the schematic representation of the work process illustrated in FIG. 4, which shows different, sequential work positions a through e. [0039] According to FIG. 4 a, the workpiece material 28 is advanced by the feed jaws 21 , 22 by the amount to be cut off, through the cutting plane 15 , represented here as a double line, and the piece to be cut off is gripped by the clamping jaws 18 , 19 . Material pieces 29 that have already been cut off, and are displaced step-wise further to the right as the machine continues to operate, can be seen to the right of the clamping jaws 18 , 19 . The saw band 9 represented by an arrow is located above the workpiece material. [0040] [0040]FIG. 4 b shows the cutting cycle, in which the saw band 9 is located in the cutting gap. In FIG. 4 c, the cutting cycle has ended and the workpiece material 28 is spaced from the cutting plane through a slight displacement to the left with the aid of the feed jaws 21 , 22 . According to FIG. 4 d, the saw band 9 is also shifted to the left by a slight amount, so it is released from the cutting surface of the workpiece section 29 that has just been separated, and is simultaneously spaced from the cutting surface of the workpiece material 28 to be processed. According to FIG. 4 e, finally, the saw band 9 has executed a contactless return stroke. Now, with the clamping jaws 18 , 19 open, the workpiece material 28 can be displaced by the amount of the material piece to be separated next. According to FIG. 4 a, the next cycle can begin after the saw band 9 has been brought back into the position according to FIG. 4 a, and the clamping jaws 18 , 19 have gripped the material again. [0041] [0041]FIGS. 5 through 8 show an option of modifying the adjustment of the saw band 9 with respect to the cutting plane for its return stroke. FIG. 5 shows a side view, partly in section, of the guide arm 12 , which shows how the guide arm can travel via rollers 30 , 31 , on the one hand, and on the guide track 25 , on the other hand. [0042] The saw-band guide 16 is disposed at the lower end of the guide arm 12 , which is shown in an enlarged section in FIG. 6. This guide includes, in addition to the saw band 9 , hard-metal plates 35 , 36 that guide the saw band, and a support roller 37 that rests against the rear of the saw band. [0043] As can be seen in FIG. 6, and in enlarged cutout views in FIGS. 7 and 8, the pistons 38 , 39 of cylinder-piston assemblies formed in the guide 16 act upon the hard-metal plates 35 , 36 in the direction of the saw band 9 , with the pistons 38 , 39 being movable, in their axial direction or their direction of movement, between a front position and a backward stopped position, so the hard-metal plates 35 , 36 can be moved back and forth equidistantly between the left and right stopped positions, with respect to FIGS. 5 through 8. The right stopped position shown in FIG. 7 corresponds to the position of the hard-metal plates 35 , 36 that is desired for the cutting cycle, while the left stopped position shown in FIG. 8 corresponds to the position of the hard-metal plates 35 , 36 , which should apply for the return stroke of the saw band 9 corresponding to FIG. 4 e. [0044] As is apparent, the construction inside the saw-band guide 16 , shown in FIGS. 5 through 8, permits a simple option for lifting the saw band. Of course, the movement control for the pistons 38 , 39 is effected by the process control of the band saw machine, corresponding to the respective requirements. [0045] The lifting of the saw band 9 for its return stroke following the cutting cycle is only described above in connection with the saw-band guide 16 of the guide arm 12 , and is sufficient in and of itself for freeing the saw band from any contact with the workpiece material during the return stroke. Of course, a corresponding construction can also be provided for the saw-band guide 17 of the guide arm 13 with the same effect. As can be seen in greater detail in FIGS. 7 and 8, the cylinder-piston assemblies 40 , 41 that include the pistons 38 , 39 can be embodied as insertable parts for the guide 16 . Moreover, as can be seen particularly in FIGS. 5 and 6, the guide 16 can be secured to the guide arm 12 in the form of a mounted part with the aid of screws 42 for permitting a rapid exchanging of parts, for example, as dictated by repair requirements. [0046] Similarly to FIGS. 5 and 6, FIGS. 9 and 10 show a different option for lifting the saw band during the saw-band return stroke. To this end, the guide roller 32 of the guide for the arm 12 is pressed against the guide track 35 [sic] with the aid of a hydraulic or pneumatic piston for holding the guide of the arm 12 with as little play as possible in a normal situation. If, however, the pressure exerted by the piston 43 is eliminated or reduced, the guide of the arm 12 has some play on the guide track 25 , so the guide arm 12 can be pivoted in the manner shown in a dashed line in FIG. 9 in the sense of the invention, namely in the direction of the workpiece material spaced from the cutting plane. [0047] To effect this pivoting movement for the return stroke of the saw band 9 , a compression spring 44 , which abuts a support arm 45 , acts on the guide arm 12 ; the support arm is in turn connected to the clamping jaw 18 that is displaceable transversely to the material-feed direction. [0048] of course, the pressure exerted by the piston 43 on the roller 32 can only be reduced if the return stroke of the saw band 9 follows the cutting cycle. The corresponding control of the pressure exerted by the piston 43 is again effected by the control device for the band saw machine. [0049] If the saw band 9 is to be brought to the cutting plane again for the next cutting cycle, the roller is again clamped against the guide track 25 due to the pressure exerted by the piston 43 , which leads to a backward pivoting of the guide arm 12 into the position illustrated in FIG. 9. [0050] Finally, FIG. 10 again shows the lower end of the guide arm illustrated in FIG. 9, along with the guide 16 , which is embodied identically to the embodiment shown in FIG. 6, except for the fact that, in FIG. 10, the hard-metal plate 35 is fixedly connected to the guide 16 by means of a screw 46 , for example, while only the hard-metal plate 36 can be pressed against the saw band by a hydraulically- or pneumatically-actuatable piston 39 . This arrangement merely serves, in a known manner, in guiding the saw band 9 with as little play as possible between the hard-metal plates 35 , 36 . [0051] The invention was explained with reference to drawings and only in connection with a specific type of band saw machine. It is, however, applicable, with the same means, to types of band saw machines other than those mentioned in the introduction to the specification, particularly to vertical band saws. [0052] It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

4y

BACKGROUND OF THE INVENTION This invention relates generally to improvements in fluid filters, and more particularly to a relief valve for a motor vehicle oil filter. A spin-on, throw-away type of fluid filter is now commonly used as an oil filter for motor vehicles because it is relatively inexpensive to mass produce and easy to install and replace. Presently, research and development regarding throwaway filters is directed to producing the filters less expensively, while maintaining or improving the filter's efficiency. A spin-on, throw-away filter usually has, among other things, a filter housing with an open end covered partially by a mounting plate having a plurality of pores to allow oil to flow from the motor to the inside of the filter and a threaded central aperture for connecting the filter to the motor and transmitting oil from the inside of the filter back to the motor, a closed or domed end, a cylindrical filter element extending substantially from the open end to the closed end and being spring biased toward the open end but being spaced a certain distance from the open end, a centertube extending longitudinally at the interior of the filter element, and a relief valve having "open" and "closed" positions and being located between the open end and the filter element. Under normal operating conditions, oil flows from the motor, through the mounting plate pores, through the filter element, through the closed relief valve, out the threaded central aperture and back to the motor. Under abnormal operating conditions, i.e., when the filter element reaches its maximum dirt holding capacity or high pressure surges are experienced, such as cold starts of the motor, the relief valve is caused to open and immediately returns oil to the motor to assure sufficient oil reaches motor parts requiring lubrication, thus by-passing the filter element altogether. Basically, two types of fluid filter relief valves are known in the art. The first type is the "tension spring housing" type and the second type is the "capturing legs" type. Each of these types of relief valve will now be generally described. The tension spring housing type of relief valve usually comprises an outlet neck or member abutting the inside of the mounting plate of the filter and extending to adjacent the filter element, a cup-shaped tension spring housing which normally functions as the relief valve oil inlet member and which is fixedly connected to and extending from the outlet neck toward the closed end of the filter and into the filter element, and a spring-biased, relatively flat piston therebetween. The outlet neck functions as the sealing surface for the piston. Examples of prior art tension spring housing type relief valves for fluid filters include: ______________________________________U.S. PAT. NO. INVENTOR ISSUED______________________________________3,061,101 HUMBERT, JR. 10/30/623,146,194 HATHAWAY 8/25/643,187,896 WILKINSON 6/8/653,315,809 HULTGREN 4/25/673,473,664 HULTGREN 10/21/693,618,775 HULTGREN 11/9/713,633,750 BRAUN ET AL. 1/11/723,640,390 GOY ET AL. 2/8/723,724,665 HALL 4/3/73______________________________________ In the tension spring housing type, both the tension spring housing and the outlet neck are usually "deep drawn". Deep drawing is a relatively expensive manufacturing method for forming large depth/diameter ratios in sheet or strip metal by considerable plastic distortion in dies. In practice, cupshaped, box-shaped or cone-shaped articles or shells are produced by forcing a drawable metal into a punch press or drop hammer. From a manufacturing cost standpoint, it is desirous to hold drawn members to a minimum depth or to use as few deep drawn members as possible. The outlet neck is deep drawn because it is necessary to keep the filter element in spaced relation to the mounting plate for proper operation of the filter. The inlet member is deep drawn in order to house the coil spring. The deep drawn outlet neck of the tension spring housing type relief valve functions as a relatively flat sealing surface for receiving the piston in sealing relation. This design results in several drawbacks from a valve efficiency and manufacturing cost standpoint. More specifically, when the filter is assembled, a vertical force is created in the direction of the mounting plate by a spring at the dome end of the filter assembly which urges the filter element toward the open end of the filter. Of course, the filter element transfers this force through the relief valve upon which it rests. The deep drawn outlet neck is eventually required to support this vertical force. Since the flat sealing surface of the outlet neck is positioned perpendicular to this vertical force, any deformation of the outlet neck caused by the vertical force, e.g., bending or collapsing of its walls, results in the sealing surface becoming non-parallel to the relatively flat piston and leakage occurs through the relief valve at pressures far below the pressure required to open the valve. In effect, the relief valve by-passes oil at times when all of the oil should be flowing through the filter element. Due to the possibility that the outlet neck will collapse or bend under the vertical force, it is necessary to manufacture the outlet neck from a material whose thickness can withstand the vertical force after assembly and thus keep the flat sealing surface parallel to the piston, i.e., perpendicular to the vertical force. Of course, a design requiring a thicker metal for the outlet neck will increase manufacturing costs, and attempting to deep draw this thicker metal will also increase costs. Further, the tension spring relief valve of the prior art uses a soft rubber piston to seal against the sealing surface of the outlet neck. Restricting an oil filter design solely to soft rubber may also increase manufacturing costs. In addition, it is generally known that a flat, soft rubber piston resting against a flat sealing surface does not offer a dependable seal when used in an oil filter. In summary, the above-discussed tension spring housing relief valve demands expensive manufacturing because deep drawing is more costly than holding drawn parts to a minimum depth or using as few deep drawn parts as possible. In addition, deep drawn outlet necks usually use a flat sealing surface which may cause leakage if the outlet neck collapses under pressure. The second type of relief valve, i.e., the capturing legs type, usually uses a long molded nylon valve having at one end a plurality of hooked legs for capturing and holding a spring and at the other end a deeply formed outlet neck. Like the tension spring housing type, the oil outlet neck or member of the capturing legs type is positioned at the open end of the filter and is deeply formed in order to properly space the filter element from the mounting plate. The capturing legs extend toward the closed end and are necessarily long in order to receive and hold the coil spring. Finally, the capturing legs relief valve comprises a relatively flat piston between the spring and outlet neck for sealing the relief valve while in the closed position. Examples of prior art capturing legs type relief valves for fluid filters include: ______________________________________U.S. PAT. NO. INVENTOR ISSUED______________________________________3,156,259 HAVELKA ET AL. 11/10/643,589,517 PALMAI 6/29/714,028,243 OFFER ET AL. 6/7/77______________________________________ The outlet neck of the capturing legs type of relief valve also functions as the sealing surface for the piston, as does the outlet neck of the tension spring housing type relief valve. Again, this design has several drawbacks from a valve efficiency and manufacturing cost standpoint. More specifically, when a filter using a capturing legs type relief valve is assembled, a vertical force is still created in the direction of the mounting plate by a spring at the dome end of the filter assembly, which urges the filter element toward the open end of the filter. Of course, the filter element transfers the vertical force through the relief valve. The outlet neck is eventually required to support this vertical force. Since the relatively flat sealing surface of the outlet neck is positioned perpendicular to the vertical force, any loss of structural integrity under the vertical force results in the sealing surface becoming non-parallel to the piston and leakage occurs through the relief valve at pressures far below the pressure required to open the valve. In effect, the relief valve passes oil at times when all of the oil should be flowing through the filter element. Since today's engines are made smaller to do the same amount of work that larger engines did a decade or more ago, these smaller engines run at higher temperatures. The molded nylon valve used in, for example, the Havelka U.S. Pat. No. 3,156,259 may, if the temperature of the oil exceeds the softening point of the nylon, lose its structural integrity causing the sealing surface to become non-parallel to the piston under the force mentioned and causing leakage around the piston. In addition, as is similar to the tension spring housing type relief valve, the capturing legs type relief valve requires a soft rubber piston to seal against the relatively flat sealing surface of the outlet neck. Again, restricting the oil filter design to a particulr type of rubber may increase overall costs and a flat, soft rubber piston does not provide an adequate seal against a relatively flat sealing surface (although the Havelka U.S. Pat. No. 3,156,259 indicates the use of a metal piston, this patent in practice also requires a molded rubber piston with a standard metal piston support to effect the desired seal, as is evidenced by the U.S. Pat No. 3,589,517 and Offer et al. U.S. Pat No. 4,028,243, which utilize the basic design of the relief valve of the Havelka et al. U.S. Pat. No. 3,156,259 along with a rubber piston). Finally, regarding the capturing legs type of relief valve, e.g., the Havelka et al. U.S. Pat. No. 3,156,259, a molded nylon valve costs far more than the electroplate tin or steel used to make the deep drawn tension spring housings and outlet necks. Thus, in regard to the capturing legs type of relief valve, the use of a molded nylon member creates manufacturing costs higher than a relief valve employing electroplate tin or steel. In addition, if the temperature of the oil exceeds the softening point of the nylon, the capturing leg member can lose its structural integrity and can cause unwanted leakage through the relief valve. In summary, each of the two prior art types of relief valve uses a deep outlet neck for spacing the filter element from the mounting plate and for functioning as the sealing surface for the piston, each uses a deep drawn or long inlet member for holding the coil spring, each uses a spring urging the piston against the outlet neck, and each is susceptable to structural deterioration under the vertical force exerted upon the relief valve once the filter is assembled. Overall, it is desirous that a relief valve be capable of the lowest cost manufacture and be capable of efficient sealing properties. For example, a design which allows for use of a relatively shallow drawn, thin electroplate material has a cost advantage over a design which uses a deep drawn thick steel or molded nylon. In addition, having flexibility in choosing the piston materials and structural design thereof is preferred to being limited to a particular type and configuration of rubber. Finally, it is desirous that a valve be capable of relatively quick and easy automated assembly and require no welding, brazing, or soldering in assembly. Thus, it can be seen that known prior art oil filter relief valves for spin-on, throw-away type oil filters continue to have manufacturing drawbacks. None of the known prior art devices have the novel features of the invention disclosed herein for eliminating such manufacturing drawbacks. SUMMARY OF THE INVENTION In light of the above-mentioned disadvantages in prior art relief valves, it is an object of the present invention to provide a relief valve having improved sealing and relief capability and being easier and more economical to manufacture and assemble. It is another object of the present invention to provide a relief valve having members which are as shallow drawn as possible, and/or a relief valve using as few deep drawn members as possible. It is another object of the present invention to provide a relief valve, wherein the outlet neck does not serve as the sealing surface for the piston. It is another object of the present invention to provide a relief valve, wherein the tension spring housing functions as the outlet neck. It is another object of the present invention to provide a relief valve wherein the outlet neck serves to both space the filter element from the mounting plate and house the coil spring, and wherein the inlet member does not have to be deep drawn. It is another object of the present invention to provide a relief valve which is made of relatively thin electroplate steel and is fully supported against vertical force directed toward the mounting plate from the dome end of the filter. It is another object of the present invention to provide a relief valve, wherein the sealing surface is pointed to improve sealing characteristics. It is another object of the present invention to provide a relief valve capable of maintaining structural integrity at oil temperatures higher than the softening temperature of nylon. It is another object of the present invention to provide a relief valve using low-cost piston materials such as rubber, paper or plastic. It is another object of the present invention to provide a relief valve which can be automatically assembled and which requires only rolling the edges of one member of the valve over the edges of another member to complete assembly. It is another object of the present invention to provide a relief valve which requires the least amount of space in the filter upon assembly. It is another object of the present invention to provide a relief valve capable of fitting into various centertube diameters. Finally, it is an object of the present invention to provide a relief valve whose sealing ability improves with time in the presence of hot oil. Additional objects and advantages of the invention will be set forth in part in the description which follows and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims. To achieve the foregoing objects and in accordance with the purpose of this invention, and as embodied and broadly described herein, the oil filter relief valve of the present invention comprises a tension spring housing having oil inlet ports and a first end and a second end, the first end being located adjacent a mounting plate of the filter (thus, functioning as the relief valve oil outlet member), a base being fixedly connected to the second end of the tension spring housing and abutting and extending into a centertube of a filter element (thus, functioning as the relief valve oil inlet member for oil entering the relief valve from the filter element), a valve seat having a pointed surface and being located in the base with a channel formed therein for conducting oil therethrough, a resilient piston normally abutting the valve seat in sealing relation, a relatively rigid piston support on the piston, and a tension spring positioned between the first end of the tension spring housing and the piston support to urge the piston into sealing relation against the pointed valve seat (thus, the piston does not seal directly against the oil outlet member, i.e., the tension spring housing, but is in spaced relation thereto). This relief valve opens when the pressure of the oil entering the oil inlet ports and the channel in the valve seat exceed a particular threshold amount, thus exerting a force on the piston greater than the downward force naturally exerted by the spring. The piston is then lifted from the valve seat and the oil is allowed to flow through the relief valve and by-pass the filter element to immediately re-enter the motor. Overall, this invention provides an economically manufactured relief valve because it uses relatively inexpensive electroplate material and rubber, and requires only inexpensive fabrication thereof, while providing effective sealing when the relief valve is in the closed position and effective by-pass when the relief valve is in the open position. BRIEF DESCRIPTION OF THE DRAWINGS For convenience in describing the preferred embodiments of the present invention in regard to the drawings included herein, the terms "downwardly" and "upwardly" are used; however, the use of these terms is not intended to be a limitation of the present invention. FIG. 1 is a partial cross-sectional view of the oil filter relief valve of the present invention positioned in a spin-on, throw-away type oil filter housing; FIG. 2 is an enlarged cross-sectional view of the oil filter relief valve of the present invention, illustrating particularly the position of the oil filter relief valve while in the "closed" position for allowing oil to flow through the filter element under normal conditions; FIG. 3 is an enlarged cross-sectional view of the oil filter relief valve of the present invention in the "open" position for allowing oil to by-pass the filter element and return to the motor immediately; FIG. 4 is an enlarged cross-sectional view of another embodiment of the oil filter relief valve of the present invention, illustrating particularly a structure which allows for a reduced overall height of the relief valve extending above the filter element; FIG. 5 is an enlarged cross-sectional view of another embodiment of the oil filter relief valve of the present invention, illustrating particularly a structure which can be used in either the upright position, as shown in FIG. 5 or in the inverted position as shown in FIG. 6; and FIG. 6 is an enlarged cross-sectional view of another embodiment of the oil filter relief valve of the present invention, illustrating particularly an oil filter relief valve similar to the one shown in FIG. 5, but which is in an inverted position. DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, the reference numeral 10 indicates an oil filter to be used with a motor (not shown). The filter has an open end 12 which usually is partially covered by a mounting plate and a closed or domed end 14. The mounting plate has a threaded central aperture (not shown) which is used to screw the spin-on oil filter 10 onto the motor. Internally of the filter 10 is a cylindrical filter element 16 being spaced from the mounting plate a predetermined distance and extending substantially to the closed end 14 of the filter 10. A centertube 17 is located longitudinally of the filter element 16 at the interior thereof. In addition, spring means, such as a leaf spring 19, is positioned between the domed end 14 and the filter element 16 to urge the filter element 16 toward the open end 12 of the filter 10. As is best seen in FIGS. 1-3, the relief valve 20 of the present invention is located near the open end 12 of the filter 10. The relief valve 20 has a first end 21 and a second end 22. More particularly, the relief valve 20 has a base 23 which has an opening 24 therein for allowing oil to flow from the filter element 16 into the relief valve 20. The outer ends 26 of the base 23 are positioned on the top of the filter element 16. The relief valve 20 also has a housing 48 mounted near the mounting plate of the filter; the position previously held by the deep drawn outlet neck of the prior art relief valves. As stated above, all prior art relief valves have deeply formed outlet necks needed to space the filter element from the mounting plate. In addition, all prior art relief valves necessarily have long or deep inlet members for housing the spring. In contrast, in the preferred embodiment of the present invention, the outlet neck (the spring housing) may be deep drawn to serve as both a means for spacing the filter element from the mounting plate and a means for housing the spring. Accordingly, the inlet neck (base) does not have to also be deep drawn as in the prior art. More particularly, the base 23 is a shallow drawn member and the tension spring housing 48 may either be deep drawn or more shallow drawn than the tension spring housings of the prior art relief valves. In either case, the present invention is capable of holding drawn parts to a minimum depth or of restricting the number of deep drawn parts to one, i.e., only the tension spring housing 48 is deep drawn and not the base 23. Located within the base 23 is a valve seat 28 which has an annular configuration and is positioned around the opening 24 in the base 23. The valve seat can be manufactured from any suitable material compatible chemically with hot oil having a temperature up to 400° F. The valve seat 28 comprises an angled oil flow channel 30 which transmits oil entering the filter 10 directly back to the motor when the relief valve is open, thus by-passing the filter element 16. The valve seat 28 terminates at one end in sealing lips or surfaces 32. The sealing lips or surfaces 32 are generally pointed or semi-sharp. The pointed or semi-sharp sealing surfaces 32 of the valve seat 28 create a tighter and more dependable seal than the flat soft rubber pistons urged against the outlet necks of the prior art relief valves. It is preferable that the sealing surface 32 be as sharp as possible which allows for use of many types of materials for the valve seat 28, some of which are relatively inexpensive. Even if an expensive molded nylon valve seat 28 is used, since the only force exerted upon the nylon would be the force of spring 60, to be discussed more fully hereafter, much higher oil temperatures above the softening temperature of nylon can be tolerated. The relief valve 20 also includes a piston 38 which is an annular member that can be produced, e.g., from rubber, plastics, or paper by molding or lathe cutting. The piston 38 may be partially covered by a piston support 40 which is also an annular member. The piston support 40 also has an opening 42 therein to allow oil to continue in its path from the opening 24 in the base 23 through the oil filter relief valve 20. Generally, the base 23, the tension spring housing 48, the piston 38 and/or the support 40 can be formed, molded or machined from metal or another relatively rigid material. For example, the present invention's improved sealing surface 32 allows the piston 38 to be made of a low cost material such as rubber impregnated paper which is stamped at assembly. The tension spring housing 48 of the relief valve 20 comprises an opening 50 therein for further allowing oil to pass through the relief valve 20. The tension spring housing 48 has lower ends 52 which abut the ends 26 of the base 23, and upper ends 54 which form an annular collar 57 for receiving a spring 60. The tension spring housing 48 also contains oil inlet ports 56 near the lower ends 52 of the tension spring housing 48. These oil inlet ports 56 allow oil that has passed through the pores in the mounting plate to enter an area 58 formed between the ends 26 of the base 23 and the valve seat 28. A spring 60 is positioned within the tension spring housing 48. The spring 60 has a first end 62 which is received by the collar 57 and a second end 64 which abuts the piston support 40. The spring 60 normally urges the piston support 40 and piston 38 into sealing relation against the sealing lips or surfaces 32 of the valve seat 28. To assemble the relief valve 20, the ends 26 of the base 23 are merely rolled over the ends 52 of the tension spring housing 48. Thus, the relief valve 20 of the present invention can be easily assembled and requires no welding, brazing or soldering as does some of the prior art devices. In addition, assembly can be easily and quickly performed by automated machinery. In light of the above discussion, it is apparent that in the present invention the "outlet neck" (tension spring housing) does not serve as the sealing surface for the piston. Accordingly, the sealing quality of the relief valve of the present invention is not dependent upon the ability of the outlet neck to maintain its structural integrity against the vertical force exerted in the assembled filter. Nevertheless, the outlet neck of the relief valve of the present invention is fully supported against this vertical force exerted toward the open end. The practical effect of the present invention is that 0.010 inch thick electroplate steel can be used to fabricate the relief valve, whereas the prior art filters using deep drawn outlet necks to withstand the vertical force require a minimum of 0.035 inch thick electroplate steel. Of course, thicker steel is more costly to buy and to fabricate. Overall, as seen in FIG. 2 the oil flow under normal conditions is as follows: oil leaves the motor and passes through the oil inlet pores in the filter mounting plate (not shown); with the relief valve 20 closed, oil moves along the outside of the filter (not shown) and enters the filter element 16 (some oil enters oil inlets 56 and channel 30 but not enough pressure is exerted at this time to overcome the force of the spring 60 and cause the piston 38 to move); the oil leaves the filter element 16 and enters the centertube 17 upon which it flows through openings 24, 42, and 50 in the relief valve 20 (as shown by arrows "A" in FIG. 2); and finally, the oil returns through the threaded central aperture 14 to the motor. As best seen in FIG. 3, under abnormal conditions, i.e., when the filter element 16 reaches its maximum dirt holding capacity or high pressure surges are experienced, such as cold starts of an engine, the relief valve 20 is caused to open and oil entering the filter 10 from the motor is immediately returned to the motor, thus bypassing the filter element 16. More particularly, when oil has difficulty passing through the filter element 16 due to being saturated with dirt, or when the motor is started and pressure is increased by the immediate surge of oil into the filter 10, the oil passing through the oil inlet ports 56, area 58 and channel 30 increases in pressure and exerts this increased pressure against the piston 38. If the pressure exceeds a particular threshold, i.e., the normal force exerted by the spring 60 upon the piston support 40 and the piston 38, the piston and the piston support 40 are moved toward the open end of the filter (not shown), and accordingly the spring 60 is partially compressed. After the piston 38 and piston support 40 move away from the valve seat 28, a space 39 is provided between the piston 38 and the valve seat 28 allowing the oil to move into the center of the relief valve 20, whereupon it moves out of the relief valve 20 and into the motor. The above-described flow of oil is represented in FIG. 3 for one side of the relief valve 20 by arrow "B". If the pressure of the oil again returns to a level below the force normally exerted by the spring 60 upon the piston support 40, the spring 60 again urges the piston support 40 and piston 38 against the valve seat 28. Of course, the sealing lips or surfaces 32 of the valve seat 28 effectively seal the valve seat 28 against the piston 38 to prevent further flow of oil through the relief valve 20 until the time comes that the oil pressure is again greater than the force normally exerted by the spring 60 upon the piston support 40 and the piston 38. It has been found through testing of the relief valve 20 of the present invention that the sealing virtues of this relief valve increase with time in hot oil. More particularly, after 500 hours at 300° F., the relief valve 20 tends to instantaneously open at the desired pressure, whereas the relief valves known in the prior art tend to open slowly as the pressure is increased. FIG. 4 illustrates another embodiment of the relief valve of the present invention, wherein the base and the tension spring housing have been modified to allow for a reduced overall height of the relief valve extending above the filter element. This capability may be advantageous for particular applications of the filter. More particularly, FIG. 4 illustrates a relief valve 66 wherein the wall 68 of the tension spring housing 70 is bent downwardly at an angle relative to the plane of the top of the filter element 72. In addition, side wall 74 of the base 76 is elongated to allow the valve seat 78 to be positioned downwardly and closer to the closed end of the filter (not shown). Finally, inlet ports 81 allow oil to flow from pores in the filter mounting plate (not shown) into the area 85 formed between the wall 74 and the valve seat 78 and finally into the channel 87. Together, the modifications to walls 68 and 74 allow the relief valve 84 in its entirety to be positioned downwardly and closer to the closed end of the filter (not shown). These modifications allow for a reduced overall height of the relief valve 84 extending above the filter element 72, thus providing greater flexibility regarding other parameters for designing and manufacturing an oil filter. FIGS. 5 and 6 illustrate other embodiments of the oil filter relief valve of the present invention, i.e., a relief valve structure which can be used in either the upright position, or in the inverted position. The embodiments shown in FIGS. 5 and 6 are capable of fitting one of several different centertube diameters. More particularly, FIG. 5 illustrates a relief valve 89 having a tension spring housing 88 with a wall 90 being modified to extend the upper ends 92 thereof to receive, e.g., a part of the filter mounting plate for example a gasket 94. In addition, wall 96 near the opening 98 in the base 100 is angled to receive a correspondingly angled bottom of the valve seat 102, and wall 104 being angled relative to the plane of the top of the filter element 106. This embodiment preferably fits, e.g., diameters of 1.6 to 1.8 inches for centertube 103. Finally, an annular ring gasket 108 is positioned between the ends 110 of the base 100 and the top of the filter element 106. With the relief valve 89 in the closed position, oil normally flows through the filter element 106 as described in relation to FIG. 2, while some oil enters the relief valve 89, as indicated by arrows "C" in FIG. 5. The embodiment of the relief valve 111 shown in FIG. 6 is similar to that shown in FIG. 5, except that the relief valve 111 is inverted relative to the embodiment shown in FIG. 5. Although the spring 112 and tension spring housing 114 of relief valve 111 now take the approximate position of the spring and tension spring housing of the prior art, i.e., extending into the centertube 116 of the filter element 118, note that the base 120 of the relief valve 111 shown in FIG. 6 does not function as the sealing surface for the piston 122. Thus, even if the base 120 should become partially bent under the vertical force caused by assembly of the filter, the sealing lips or surfaces 124 of the valve seat 126 will be able to maintain an effective seal with the piston 122. The oil inlet ports 128 for this embodiment are positioned in the wall 130 of the base 120 and not in the wall 132 of the tension spring housing 114, as was seen in FIGS. 1-5. The wall 134 of the tension spring housing 114 may fit within various diameters for centertube 116. For example, the tension spring housing 114 preferably fits into a centertube 116 diameter of 1.225 to 1.550 inches. The wall 138 in the base 120 receives part of the filter mounting plate for example a gasket 140. With the relief valve 111 in the closed position, oil normally flows through the filter element 118, as described in relation to FIG. 2, while some oil enters the relief valve 111, as indicated by arrows "D" in FIG. 6. It can be seen from the above description of the preferred embodiments that the present invention provides a relief valve which is less expensive to make and which provides more reliable sealing and relief properties than the prior art. The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention and the appended claims and their equivalents.

4y

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation application of and claims priority to U.S. patent application Ser. No. 12/826,864, filed Jun. 30, 2010, the entirety of which is herein incorporated by reference in its entirety. FIELD OF INVENTION The present invention relates generally to compositions for topical application to the skin which comprise N-substituted sulfonyloxybenzylamines and the use of such compositions to improve the aesthetic appearance of the skin. BACKGROUND OF THE INVENTION Collagen is the body's major structural protein and is composed of three protein chains wound together in a tight triple helix. This unique structure gives collagen a greater tensile strength than steel. Approximately 33 percent of the protein in the body is collagen. This protein supports tissues and organs and connects these structures to bones. In fact, bones are also composed of collagen combined with certain minerals such as calcium and phosphorus. Collagen plays a key role in providing the structural scaffolding surrounding cells that helps to support cell shape and differentiation, similar to how steel rods reinforce a concrete block. The mesh-like collagen network binds cells together and provides the supportive framework or environment in which cells develop and function, and tissues and bones heal. Collagen is created by fibroblasts, which are specialized skin cells located in the dermis. Fibroblasts also produce other skin structural proteins such as elastin (a protein which gives the skin its ability to snap back) and glucosaminoglycans (GAGs). GAGs make up the ground substance that keeps the dermis hydrated. In order to signal or turn on the production of skin structural proteins, fibroblast cells have specially shaped receptors on their outside membranes that act as binding sites to which signal molecules with a matching shape can fit. When the receptors are bound by the correct combination of signal molecules (called fibroblast growth factors, or FGFs), the fibroblast begins the production of collagen. The stimulation of collagen gives the skin its strength, durability, and smooth, plump appearance. The invention thus provides new compositions and methods for stimulating collagen production. It is a further object of the invention to improve the overall appearance of skin, including treating, reversing, and/or preventing signs of aging, such as skin wrinkles, by stimulating collagen production with cosmetic compositions comprising effective amounts of N-substituted sulfonyloxybenzylamines. The foregoing discussion is presented solely to provide a better understanding of nature of the problems confronting the art and should not be construed in any way as an admission as to prior art nor should the citation of any reference herein be construed as an admission that such reference constitutes “prior art” to the instant application. SUMMARY OF THE INVENTION In accordance with the foregoing objectives and others, it has surprisingly been found that N-substituted sulfonyloxybenzylamines are potent stimulators of collagen production and thus are beneficial agents against various signs of intrinsic aging and photo-aging of skin. In one aspect of the invention, a method is provided for improving the aesthetic appearance of human skin comprising topically applying to an area of the skin in need thereof an effective amount of an N-substituted sulfonyloxybenzylamine or a cosmetically acceptable salt thereof in a cosmetically acceptable vehicle. In another aspect of the invention, cosmetic compositions are provided for improving the aesthetic appearance of skin comprising, in a cosmetically acceptable vehicle, an effective amount of an N-substituted sulfonyloxybenzylamine having the structure of formula I: where W 1 , W 2 are independently CO, CO 2 , CONH, SO 2 or PO 3 ; R 1 , R 2 and R 3 are independently C 1-20 hydrocarbons, each independently selected from alkyl, cycloalkyl, haloalkyl, alkoxyalkyl, heteroalkyl, aryl, arylalkyl, alkylaryl, heteroarylalkyl, and alkylheteroaryl, and each being optionally substituted with C and/or 1-6 heteroatoms, selected from halogens, O, N, S, and with S optionally being oxidized; X, Y each independently represent H or an optionally substituted alkyl, haloalkyl, alkoxy, amino, aminoalkyl, haloalkoxy, alkenyl, and where adjacent X, Y taken together can form a 5, 6, or 7 member ring; R 1 , R 2 and R 3 each may also be optionally substituted with, for example, amino, aminoalkyl, alkoxy, haloalkoxy, haloalkyl, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, etc. and wherein the —O—W 2 —R 1 group is attached to the phenyl ring at the 2-, 3- or 4-position. Also provided is a method of treating one or more signs of skin aging comprising topically applying to skin in need thereof an N-substituted sulfonyloxybenzylamine according to formula I in an amount effective to enhance collagen. In another aspect of the invention, a method of treating, ameliorating, and/or preventing fine lines or wrinkles or sagging in human skin is provided, comprising topically applying to skin in need thereof, including applying directly to a wrinkle or fine line, a composition comprising a N-substituted sulfonyloxybenzylamine according to formula I in an amount effective to enhance collagen. These and other aspects of the present invention will be better understood by reference to the following detailed description and accompanying figures. DETAILED DESCRIPTION All terms used herein are intended to have their ordinary meaning unless otherwise provided. The present invention provides compositions for topical application which comprise and effective amount of N-substituted sulfonyloxybenzylamines or a related compound to treat, reverse, ameliorate and/or prevent signs of skin aging. Such signs of skin aging include without limitation, the following: (a) treatment, reduction, and/or prevention of fine lines or wrinkles, (b) reduction of skin pore size, (c) improvement in skin thickness, plumpness, and/or tautness; (d) improvement in skin suppleness and/or softness; (e) improvement in skin tone, radiance, and/or clarity; (f) improvement in procollagen and/or collagen production; (g) improvement in maintenance and remodeling of elastin; (h) improvement in skin texture and/or promotion of retexturization; (i) improvement in skin barrier repair and/or function; (j) improvement in appearance of skin contours; (k) restoration of skin luster and/or brightness; (l) replenishment of essential nutrients and/or constituents in the skin; (m) decreased by aging and/or menopause; (n) improvement in skin moisturization; (o) increase in skin elasticity and/or resiliency; (p) treatment, reduction, and/or prevention of skin sagging and/or (q) reduction of pigment spots. In practice, the compositions of the invention are applied to skin in need of treatment. That is, skin which suffers from a deficiency or loss in any of the foregoing attributes or which would otherwise benefit from improvement in any of the foregoing skin attributes. In certain preferred embodiments the compositions and methods of the invention are directed to the prevention, treatment, and/or amelioration of fine lines and/or wrinkles in the skin. In this case, the compositions are applied to skin in need of treatment, by which is meant skin having wrinkles and/or fine lines. Preferably, the compositions are applied directly to the fine lines and/or wrinkles. The compositions and methods are suitable for treating fine lines and/or wrinkles on any surface of the skin, including without limitation, the skin of the face, neck, and/or hands. The cosmetic compositions for treating a skin condition associated with loss of collagen and/or elastin fiber comprise, in a cosmetically acceptable vehicle, an amount of a N-substituted sulfonyloxybenzylamineseffective to enhance collagen. These collagen enhancing agents may have the structure of formula (I): In formula (I), W 1 and W 2 are independently CO, CO 2 , CONH, SO 2 , or PO 3 ; R 1 , R 2 and R 3 are independently alkyl, cycloalkyl, haloalkyl, alkoxyalkyl, arylaklyl or heteroalkyl, each which may be optionally substituted with C and/or 1-6 heteroatoms, selected from halogens, O, N, S, and with S optionally being oxidized; X, Y each independently represent H or are optionally substituted alkyl, haloalkyl, alkoxy, amino, aminoalkyl, haloalkoxy, alkenyl, and where adjacent X, Y taken together can form a 5, 6, or 7 member ring. In one embodiment, W 1 and W 2 are SO 2 ; X and Y are H; R 1 , R 2 each represent C 1 -C 8 alkyl, preferably C 1 -C 4 alkyl, and R 3 is an aliphatic alkyl, C 1 -C 8 substituted or unsubstituted cycloalkyl, or an aromatic hydrocarbon radical, as exemplified by C 6 aromatic hydrocarbon radical which may be a susbstituted or unsubstituted aryl (e.g., phenyl). In other embodiments R 1 , R 2 , R 3 independently represent a lower alkyl group (e.g., methyl, ethyl, propyl, butyl, etc.), typically methyl or ethyl). In other embodiments, R 1 , R 2 represent, independently at each occurrence aliphatic C 1 -C 8 hydrocarbon radicals; including aliphatic C 1 -C 6 hydrocarbon radicals, aliphatic C 1 -C 8 hydrocarbon radicals, or an aliphatic C 1 -C 6 hydrocarbon radicals, as exemplified by substituted or unsubstituted branched, straight chain or cyclic, alkyl, alkenyl (e.g., vinyl, allyl, etc.), and alkynyl moieties; C 6 -C 20 aromatic hydrocarbon radicals, including C 6 -C 12 aromatic hydrocarbon radicals, C 6 -C 10 aromatic hydrocarbon radicals, or C 6 aromatic hydrocarbon radicals, as exemplified by substituted or unsubstituted aryl (e.g., phenyl), alkyl-aryl (e.g., benzyl), aryl-alkyl, and the like; or C 1 -C 20 heteroaryl radicals including one or more heteroatoms selected from O, N, and S in the ring; including C 1 -C 12 heteroaromatic radicals, C 1 -C 8 heteroaromatic radicals, and C 1 -C 6 heteroaromatic radicals, as exemplified by heteroaryl, alkyl-heteroaryl, heteroarylalkyl and the like. R 1 , R 2 and R 3 each may also be optionally substituted with, for example, amino, aminoalkyl, alkoxy, haloalkoxy, haloalkyl, halogen, amino, aminoalkyl, alkoxy, haloalkoxy, haloalkyl, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, etc. In some embodiments, W 1 is CONH, W 2 is SO 2 , X and Y are H, R 1 is C 1 -C 8 alkyl, R 2 is C 1 -C 8 alkyl or aralkyl, and R 3 is alkyl, cycloalkyl, arylalkyl or heteroalkyl. In other embodiments, W 1 represents a carbonyl group —(C═O)—, W 2 is SO 2 , X and Y are H, R 1 is C 1 -C 8 alkyl, R 2 is C 1 -C 8 alkyl or arylalkyl, and R 3 is alkyl, cycloalkyl, arylalkyl or heteroalkyl. Further, any nitrogen atom may be optionally oxidized to the N-oxide or can be quarternized, for example with loweralkyl halides, such as methyl, ethyl, propyl, and butyl chloride, bromides, and iodides; dialkyl sulfates like dimethyl, diethyl, dibutyl, and diamyl sulfates, long chain halides such as decyl, lauryl, myristyl and stearyl chlorides, bromides and iodides, aralkyl halides such as benzyl and phenethyl bromides, to name a few. In one embodiment according to formula (I), W 1 and W 2 are SO 2 , as shown in formula (Ia). where X and Y are H, R 1 is an alkyl group, R 2 is i-butyl and R 3 is a phenyl group. In another embodiment, W 1 is SO 2 and W 2 will be a group —CONH—, X and Y are H, R 1 is an alkyl group, R 2 is an alkyl group and R 3 is substituted phenyl group as shown in formula (Ib): where the —OSO 2 R 1 group is positioned on the phenyl ring at position 3- or 4-. Preferably R is a methyl group, R 2 is isobutyl and R 3 is a 2-ethyl phenyl group. In a further embodiment, W 1 is a be a carbonyl group (—CO—), W 2 is SO 2 , X and Y are H, R 1 is an alkyl group, R 2 is alkyl group and R 3 is an alkyl group or substituted phenyl group as shown in formula (Ic): where R 1 is preferably methyl, R 2 is an alkyl group or an alkoxy group and R 3 is a substituted phenyl group. In a particular embodiment, a cosmetic composition comprises, in a cosmetically acceptable vehicle, preferably a water-in-oil or oil-in-water emulsion, from about 0.0001% to about 90% by weight of a N-substituted sulfonyloxybenzylamine having the structure: or a cosmetically acceptable salt thereof. In another particular embodiment, a cosmetic composition comprises, in a cosmetically acceptable vehicle, preferably a water-in-oil or oil-in-water emulsion, from about 0.0001% to about 90% by weight of a N-substituted sulfonyloxybenzylamine having the structure: or a cosmetically acceptable salt thereof. The invention embraces the use of cosmetically or pharmaceutically acceptable (e.g., non-toxic and/or non-irritating) salts. Examples of the salts of the compounds in the present invention include salts with alkali metals such as sodium and potassium; salts with alkaline-earth metals such as calcium and magnesium; salts with amines such as monoethanolamine; salts with inorganic acids such as hydrochloric acid and sulfuric acid; and salts with organic acids such as citric acid and acetic acid. Special mention may be made of hydrochloride salts. The cosmetic compositions according to the invention can be formulated in a variety of forms for topical application and will comprise from about 0.00001% to about 90% by weight of one or more compounds according to formula (I), and preferably will comprise from about 0.001% to about 25% by weight, and more preferably from about 0.001% to about 1% by weight. The compositions will comprise an effective amount of the N-substituted sulfonyloxybenzylamine compounds according to formula (I), by which is meant an amount sufficient to enhance collagen in s given area of skin when topically applied thereto. The composition may be formulated in a variety of product forms, such as, for example, a lotion, cream, serum, spray, aerosol, cake, ointment, essence, gel, paste, patch, pencil, towelette, mask, stick, foam, elixir, concentrate, and the like, particularly for topical administration. Preferably the composition is formulated as a lotion, cream, ointment, or gel. The compositions can include a cosmetically acceptable vehicle. Such vehicles may take the form of any known in the art suitable for application to skin and may include, but are not limited to, water; vegetable oils; mineral oils; esters such as octal palmitate, isopropyl myristate and isopropyl palmitate; ethers such as dicapryl ether and dimethyl isosorbide; alcohols such as ethanol and isopropanol; fatty alcohols such as cetyl alcohol, cetearyl alcohol, stearyl alcohol and biphenyl alcohol; isoparaffins such as isooctane, isododecane and is hexadecane; silicone oils such as cyclomethicone, dimethicone, dimethicone cross-polymer, polysiloxanes and their derivatives, preferably organomodified derivatives; hydrocarbon oils such as mineral oil, petrolatum, isoeicosane and polyisobutene; polyols such as propylene glycol, glycerin, butylene glycol, pentylene glycol and hexylene glycol; waxes such as beeswax and botanical waxes; or any combinations or mixtures of the foregoing. The vehicle may comprise an aqueous phase, an oil phase, an alcohol, a silicone phase or mixtures thereof. The cosmetically acceptable vehicle may also comprise an emulsion. Non-limiting examples of suitable emulsions include water-in-oil emulsions, oil-in-water emulsions, silicone-in-water emulsions, water-in-silicone emulsions, wax-in-water emulsions, water-oil-water triple emulsions or the like having the appearance of a cream, gel or microemulsions. The emulsion may include an emulsifier, such as a nonionic, anionic or amphoteric surfactant. The oil phase of the emulsion preferably has one or more organic compounds, including emollients; humectants (such as propylene glycol and glycerin); other water-dispersible or water-soluble components including thickeners such as veegum or hydroxyalkyl cellulose; gelling agents, such as high MW polyacrylic acid, i.e. CARBOPOL 934; and mixtures thereof. The emulsion may have one or more emulsifiers capable of emulsifying the various components present in the composition. The compounds suitable for use in the oil phase include without limitation, vegetable oils; esters such as octal palmitate, isopropyl myristate and isopropyl palmitate; ethers such as dicapryl ether; fatty alcohols such as cetyl alcohol, stearyl alcohol and behenyl alcohol; isoparaffins such as isooctane, isododecane and isohexadecane; silicone oils such as dimethicones, cyclic silicones, and polysiloxanes; hydrocarbon oils such as mineral oil, petrolatum, isoeicosane and polyisobutene; natural or synthetic waxes; and the like. Suitable hydrophobic hydrocarbon oils may be saturated or unsaturated, have an aliphatic character and be straight or branched chained or contain alicyclic or aromatic rings. The oil-containing phase may be composed of a singular oil or mixtures of different oils. Hydrocarbon oils include those having 6-20 carbon atoms, more preferably 10-16 carbon atoms. Representative hydrocarbons include decane, dodecane, tetradecane, tridecane, and C 8-20 isoparaffins. Paraffinic hydrocarbons are available from Exxon under the ISOPARS trademark, and from the Permethyl Corporation. In addition, C 8-20 paraffinic hydrocarbons such as C 12 isoparaffin (isododecane) manufactured by the Permethyl Corporation having the tradename Permethyl 99ATM are also contemplated to be suitable. Various commercially available C 16 isoparaffins, such as isohexadecane (having the tradename Permethyl RTM) are also suitable. Examples of preferred volatile hydrocarbons include polydecanes such as isododecane and isodecane, including for example, Permethyl-99A (Presperse Inc.) and the C 7 -C 8 through C 12 -C 15 isoparaffins such as the Isopar Series available from Exxon Chemicals. A representative hydrocarbon solvent is isododecane. The oil phase may comprise one or more waxes, including for example, rice bran wax, carnauba wax, ouricurry wax, candelilla wax, montan waxes, sugar cane waxes, ozokerite, polyethylene waxes, Fischer-Tropsch waxes, beeswax, microcrystaline wax, silicone waxes, fluorinated waxes, and any combination thereof. Non-limiting emulsifiers included emulsifying waxes, emulsifying polyhydric alcohols, polyether polyols, polyethers, mono- or di-ester of polyols, ethylene glycol mono-stearates, glycerin mono-stearates, glycerin di-stearates, silicone-containing emulsifiers, soya sterols, fatty alcohols such as cetyl alcohol, fatty acids such as stearic acid, fatty acid salts, and mixtures thereof. The preferred emulsifiers include soya sterol, cetyl alcohol, stearic acid, emulsifying wax, and mixtures thereof. Other specific emulsifiers that can be used in the composition of the present invention include, but are not limited to, one or more of the following: sorbitan esters; polyglyceryl-3-diisostearate; sorbitan monostearate, sorbitan tristearate, sorbitan sesquioleate, sorbitan monooleate; glycerol esters such as glycerol monostearate and glycerol monooleate; polyoxyethylene phenols such as polyoxyethylene octyl phenol and polyoxyethylene nonyl phenol; polyoxyethylene ethers such as polyoxyethylene cetyl ether and polyoxyethylene stearyl ether; polyoxyethylene glycol esters; polyoxyethylene sorbitan esters; dimethicone copolyols; polyglyceryl esters such as polyglyceryl-3-diisostearate; glyceryl laurate; Steareth-2, Steareth-10, and Steareth-20, to name a few. Additional emulsifiers are provided in the INCI Ingredient Dictionary and Handbook 11th Edition 2006, the disclosure of which is hereby incorporated by reference. These emulsifiers typically will be present in the composition in an amount from about 0.001% to about 10% by weight, in particular in an amount from about 0.01% to about 5% by weight, and more preferably, below 1% by weight. The oil phase may comprise one or more volatile and/or non-volatile silicone oils. Volatile silicones include cyclic and linear volatile dimethylsiloxane silicones. In one embodiment, the volatile silicones may include cyclodimethicones, including tetramer (D4), pentamer (D5), and hexamer (D6) cyclomethicones, or mixtures thereof. Particular mention may be made of the volatile cyclomethicone-hexamethyl cyclotrisiloxane, octamethyl-cyclotetrasiloxane, and decamethyl-cyclopentasiloxane. Suitable dimethicones are available from Dow Corning under the name Dow Corning 200® Fluid and have viscosities ranging from 0.65 to 600,000 centistokes or higher. Suitable non-polar, volatile liquid silicone oils are disclosed in U.S. Pat. No. 4,781,917, herein incorporated by reference in its entirety. Additional volatile silicones materials are described in Todd et al., “Volatile Silicone Fluids for Cosmetics”, Cosmetics and Toiletries, 91:27-32 (1976), herein incorporated by reference in its entirety. Linear volatile silicones generally have a viscosity of less than about 5 centistokes at 25° C., whereas the cyclic silicones have viscosities of less than about 10 centistokes at 25° C. Examples of volatile silicones of varying viscosities include Dow Corning 200, Dow Corning 244, Dow Corning 245, Dow Corning 344, and Dow Corning 345, (Dow Corning Corp.); SF-1204 and SF-1202 Silicone Fluids (G.E. Silicones), GE 7207 and 7158 (General Electric Co.); and SWS-03314 (SWS Silicones Corp.). Linear, volatile silicones include low molecular weight polydimethylsiloxane compounds such as hexamethyldisiloxane, octamethyltrisiloxane, decamethyltetrasiloxane, and dodecamethylpentasiloxane, to name a few. Non-volatile silicone oils will typically comprise polyalkylsiloxanes, polyarylsiloxanes, polyalkylarylsiloxanes, or mixtures thereof. Polydimethylsiloxanes are preferred non-volatile silicone oils. The non-volatile silicone oils will typically have a viscosity from about 10 to about 60,000 centistokes at 25° C., preferably between about 10 and about 10,000 centistokes, and more preferred still between about 10 and about 500 centistokes; and a boiling point greater than 250° C. at atmospheric pressure. Non limiting examples include dimethyl polysiloxane (dimethicone), phenyl trimethicone, and diphenyldimethicone. The volatile and non-volatile silicone oils may optionally be substituted will various functional groups such as alkyl, aryl, amine groups, vinyl, hydroxyl, haloalkyl groups, alkylaryl groups, and acrylate groups, to name a few. The water-in-silicone emulsion may be emulsified with a nonionic surfactant (emulsifier) such as, for example, polydiorganosiloxane-polyoxyalkylene block copolymers, including those described in U.S. Pat. No. 4,122,029, the disclosure of which is hereby incorporated by reference. These emulsifiers generally comprise a polydiorganosiloxane backbone, typically polydimethylsiloxane, having side chains comprising -(EO)m- and/or —(PO)n- groups, where EO is ethyleneoxy and PO is 1,2-propyleneoxy, the side chains being typically capped or terminated with hydrogen or lower alkyl groups (e.g., C 1-6 , typically C 1-3 ). Other suitable water-in-silicone emulsifiers are disclosed in U.S. Pat. No. 6,685,952, the disclosure of which is hereby incorporated by reference herein. Commercially available water-in-silicone emulsifiers include those available from Dow Corning under the trade designations 3225C and 5225C FORMULATION AID; SILICONE SF-1528 available from General Electric; ABIL EM 90 and EM 97, available from Goldschmidt Chemical Corporation (Hopewell, Va.); and the SILWET series of emulsifiers sold by OSI Specialties (Danbury, Conn.). Examples of water-in-silicone emulsifiers include, but are not limited to, dimethicone PEG 10/15 crosspolymer, dimethicone copolyol, cetyl dimethicone copolyol, PEG-15 lauryl dimethicone crosspolymer, laurylmethicone crosspolymer, cyclomethicone and dimethicone copolyol, dimethicone copolyol (and) caprylic/capric triglycerides, polyglyceryl-4 isostearate (and) cetyl dimethicone copolyol (and) hexyl laurate, and dimethicone copolyol (and) cyclopentasiloxane. Preferred examples of water-in-silicone emulsifiers include, without limitation, PEG/PPG-18/18 dimethicone (trade name 5225C, Dow Corning), PEG/PPG-19/19 dimethicone (trade name BY25-337, Dow Corning), Cetyl PEG/PPG-10/1 dimethicone (trade name Abil EM-90, Goldschmidt Chemical Corporation), PEG-12 dimethicone (trade name SF 1288, General Electric), lauryl PEG/PPG-18/18 methicone (trade name 5200 FORMULATION AID, Dow Corning), PEG-12 dimethicone crosspolymer (trade name 9010 and 9011 silicone elastomer blend, Dow Corning), PEG-10 dimethicone crosspolymer (trade name KSG-20, Shin-Etsu), and dimethicone PEG-10/15 crosspolymer (trade name KSG-210, Shin-Etsu). The water-in-silicone emulsifiers typically will be present in the composition in an amount from about 0.001% to about 10% by weight, in particular in an amount from about 0.01% to about 5% by weight, and more preferably, below 1% by weight. The aqueous phase of the emulsion may include one or more additional solvents, including lower alcohols, such as ethanol, isopropanol, and the like. The volatile solvent may also be a cosmetically acceptable ester such as butyl acetate or ethyl acetate; ketones such as acetone or ethyl methyl ketone; or the like. The oil-containing phase will typically comprise from about 10% to about 99%, preferably from about 20% to about 85%, and more preferably from about 30% to about 70% by weight, based on the total weight of the emulsion, and the aqueous phase will typically comprise from about 1% to about 90%, preferably from about 5% to about 70%, and more preferably from about 20% to about 60% by weight of the total emulsion. The aqueous phase will typically comprise from about 25% to about 100%, more typically from about 50% to about 95% by weight water. The compositions may include liposomes. The liposomes may comprise other additives or substances and/or may be modified to more specifically reach or remain at a site following administration. Additionally, the compositions may incorporate encapsulation and/or microencapsulation technology. As is well known in the art, encapsulating materials can be selected which will release the composition upon exposure to moisture, pH change, temperature change, solubility change, or mechanical shear or rupture. Suitable encapsulating materials and methods of preparing encapsulated materials, such as spray drying, extrusion, coacervation, fluidized bed coating, liposome entrapment and others, are disclosed in, for example, U.S. Patent Application Publication No. 2005/0000531 to Shi; Uhlmann, et al., “Flavor encapsulation technologies: an overview including recent developments” Perfumer and Flavorist, 27, 52-61, 2002; and “Selection of Coating and Microencapsulation Processes” by Robert E. Sparks and Irwin Jacobs in Controlled-Release Delivery Systems for Pesticides, Herbert B. Scher ed., Marcel Dekker, New York, N.Y., 1999, pp. 3-29, the contents of which are hereby incorporated by reference. The compositions incorporating encapsulation and/or microencapsulation technology may form nanoparticles. The term “nanoparticle” as used herein refers to a nanometer-sized particle, having a diameter of between about 1 nanometer and about 999 nanometers; the term “nanoparticles” as used herein refers to nanometer-sized particles, nanoclusters, clusters, particles, small particles, and nanostructured materials. The composition may optionally comprise other cosmetic actives and excipients, obvious to those skilled in the art including, but not limited to, fillers, emulsifying agents, antioxidants, surfactants, film formers, chelating agents, gelling agents, thickeners, emollients, humectants, moisturizers, vitamins, minerals, viscosity and/or rheology modifiers, sunscreens, keratolytics, depigmenting agents, retinoids, hormonal compounds, alpha-hydroxy acids, alpha-keto acids, anti-mycobacterial agents, antifungal agents, antimicrobials, antivirals, analgesics, lipidic compounds, anti-allergenic agents, H1 or H2 antihistamines, anti-inflammatory agents, anti-irritants, antineoplastics, immune system boosting agents, immune system suppressing agents, anti-acne agents, anesthetics, antiseptics, insect repellents, skin cooling compounds, skin protectants, skin penetration enhancers, exfollients, lubricants, fragrances, colorants, depigmenting agents, hypopigmenting agents, preservatives, stabilizers, pharmaceutical agents, photostabilizing agents, sunscreens, and mixtures thereof. In addition to the foregoing, the cosmetic compositions of the invention may contain any other compound for the treatment of skin disorders. Colorants may include, for example, organic and inorganic pigments and pearlescent agents. Suitable inorganic pigments include, but are not limited to, titanium oxide, zirconium oxide and cerium oxide, as well as zinc oxide, iron oxide, chromium oxide and ferric blue. Suitable organic pigments include barium, strontium, calcium, and aluminium lakes and carbon black. Suitable pearlescent agents include mica coated with titanium oxide, with iron oxide, or with natural pigment. Various fillers and additional components may be added. Fillers are normally present in an amount of about 0 weight % to about 20 weight %, based on the total weight of the composition, preferably about 0.1 weight % to about 10 weight %. Suitable fillers include without limitation silica, treated silica, talc, zinc stearate, mica, kaolin, Nylon powders such as Orgasol™, polyethylene powder, Teflon™, starch, boron nitride, copolymer microspheres such as Expancel™ (Nobel Industries), Polytrap™ (Dow Corning) and silicone resin microbeads (Tospearl™ from Toshiba), and the like. In one embodiment of the invention, the compositions may include additional skin actives such as, but are not limited to, botanicals, keratolytic agents, desquamating agents, keratinocyte proliferation enhancers, collagenase inhibitors, elastase inhibitors, depigmenting agents, anti-inflammatory agents, steroids, anti-acne agents, antioxidants, salicylic acid or salicylates, thiodipropionic acid or esters thereof, and advanced glycation end-product (AGE) inhibitors. In a specific embodiment, the composition may comprise at least one additional botanical, such as, for example, a botanical extract, an essential oil, or the plant itself. Suitable botanicals include, without limitation, extracts from Abies pindrow, Acacia catechu, Aloe, Amorphophallus campanulatus, Anogeissus latifolia, Asmunda japonica, Azadirachta indica, Butea frondosa, Butea monosperma, Cedrus deodara, Chamomile, Emblica officinalis, Ficus benghalensis, Glycyrrhiza glabra, Humilus scandens, Ilex purpurea Hassk, Innula racemosa, Ligusticum chiangxiong, Ligusticum lucidum, Mallotus philippinensis, Melicope hayesil, Mimusops elengi, Morinda citrifolia, Moringa oleifera, Naringi crenulata, Nerium indicum, Piper betel, Pouzolzia petandra, Psoralea corylifolia, Rhinacanthus nasutus, Sapindus rarek, Sesbania grandiflora, Stenoloma chusana, Terminalia bellerica , tomato glycolipid and mixtures thereof. The composition may comprise additional active ingredients having anti-aging benefits, as it is contemplated that synergistic improvements may be obtained with such combinations. Exemplary anti-aging components include, without limitation, botanicals (e.g., Butea Frondosa extract); phytol, thiodipropionic acid (TDPA) and esters thereof; retinoids (e.g., all-trans retinoic acid, 9-cis retinoic acid, phytanic acid and others); hydroxy acids (including alpha-hydroxyacids and beta-hydroxyacids), salicylic acid and salicylates; exfoliating agents (e.g., glycolic acid, 3,6,9-trioxaundecanedioic acid, etc.), estrogen synthetase stimulating compounds (e.g., caffeine and derivatives); compounds capable of inhibiting 5 alpha-reductase activity (e.g., linolenic acid, linoleic acid, finasteride, and mixtures thereof); barrier function enhancing agents (e.g., ceramides, glycerides, cholesterol and its esters, alpha-hydroxy and omega-hydroxy fatty acids and esters thereof, etc.); collagenase inhibitors; and elastase inhibitors; to name a few. Exemplary retinoids include, without limitation, retinoic acid (e.g., all-trans or 13-cis) and derivatives thereof, retinol (Vitamin A) and esters thereof, such as retinol palmitate, retinol acetate and retinol propionate, and salts thereof. In another embodiment, the topical compositions of the present invention may also include one or more of the following: a skin penetration enhancer, an emollient, a skin plumper, an optical diffuser, a sunscreen, an exfoliating agent, and an antioxidant. An emollient provides the functional benefits of enhancing skin smoothness and reducing the appearance of fine lines and coarse wrinkles Examples include isopropyl myristate, petrolatum, isopropyl lanolate, silicones (e.g., methicone, dimethicone), oils, mineral oils, fatty acid esters, or any mixtures thereof. The emollient may be preferably present from about 0.1 wt % to about 50 wt % of the total weight of the composition. A skin plumper serves as a collagen enhancer to the skin. An example of a suitable, and preferred, skin plumper is palmitoyl oligopeptide. Other skin plumpers are collagen and/or other glycosaminoglycan (GAG) enhancing agents. When present, the skin plumper may comprise from about 0.1 wt % to about 20 wt % of the total weight of the composition. An optical diffuser is a particle that changes the surface optometrics of skin, resulting in a visual blurring and softening of, for example, lines and wrinkles Examples of optical diffusers that can be used in the present invention include, but are not limited to, boron nitride, mica, nylon, polymethylmethacrylate (PMMA), polyurethane powder, sericite, silica, silicone powder, talc, Teflon, titanium dioxide, zinc oxide, or any mixtures thereof. When present, the optical diffuser may be present from about 0.01 wt % to about 20 wt % of the total weight of the composition. A sunscreen for protecting the skin from damaging ultraviolet rays may also be included. Preferred sunscreens are those with a broad range of UVB and UVA protection, such as octocrylene, avobenzone (Parsol 1789), octyl methoxycinnamate, octyl salicylate, oxybenzone, homosylate, benzophenone, camphor derivatives, zinc oxide, and titanium dioxide. When present, the sunscreen may comprise from about 0.01 wt % to about 70 wt % of the composition. Suitable exfoliating agents include, for example, alpha-hydroxyacids, beta-hydroxyacids, oxaacids, oxadiacids, and their derivatives such as esters, anhydrides and salts thereof. Suitable hydroxy acids include, for example, glycolic acid, lactic acid, malic acid, tartaric acid, citric acid, 2-hydroxyalkanoic acid, mandelic acid, salicylic acid and derivatives thereof. A preferred exfoliating agent is glycolic acid. When present, the exfoliating agent may comprise from about 0.1 wt % to about 80 wt % of the composition. An antioxidant functions, among other things, to scavenge free radicals from skin to protect the skin from environmental aggressors. Examples of antioxidants that may be used in the present compositions include compounds having phenolic hydroxy functions, such as ascorbic acid and its derivatives/esters; beta-carotene; catechins; curcumin; ferulic acid derivatives (e.g. ethyl ferulate, sodium ferulate); gallic acid derivatives (e.g., propyl gallate); lycopene; reductic acid; rosmarinic acid; tannic acid; tetrahydrocurcumin; tocopherol and its derivatives; uric acid; or any mixtures thereof. Other suitable antioxidants are those that have one or more thiol functions (—SH), in either reduced or non-reduced form, such as glutathione, lipoic acid, thioglycolic acid, and other sulfhydryl compounds. The antioxidant may be inorganic, such as bisulfites, metabisulfites, sulfites, or other inorganic salts and acids containing sulfur. Compositions of the present invention may comprise an antioxidant preferably from about 0.001 wt % to about 10 wt %, and more preferably from about 0.01 wt % to about 5 wt %, of the total weight of the composition. Other conventional additives include: vitamins, such as tocopherol and ascorbic acid; vitamin derivatives such as ascorbyl monopalmitate; thickeners such as hydroxyalkyl cellulose; gelling agents; structuring agents such as bentonite, smectite, magnesium aluminum silicate and lithium magnesium silicate; metal chelating agents such as EDTA; pigments such as zinc oxide and titanium dioxide; colorants; emollients; and humectants. It is preferred that the composition be essentially free of components having a strong oxidizing potential, including for example, organic or inorganic peroxides. By “essentially free of” these components is meant that the amounts present are insufficient to have a measurable impact on the collagen enhancing activity of the N-substituted sulfonyloxybenzylamine. In some embodiments, this will be, on a molar basis in relation to the amount of N-substituted sulfonyloxybenzylamine, less than 1%. In one embodiment, the composition of the invention comprising an N-substituted sulfonyloxybenzylamine may have a pH between about 1 and about 8. In certain embodiments, the pH of the composition will be acidic, i.e., less than 7.0., and preferably will be between about 2 and about 7, more preferably between about 3.5 and about 5.5. The invention provides a method for treating aging skin by topically applying a composition comprising a N-substituted sulfonyloxybenzylamine, preferably in a cosmetically acceptable vehicle, over the affected area for a period of time sufficient to reduce, ameliorate, reverse or prevent dermatological signs of aging. This method is particularly useful for treating signs of skin photoaging and intrinsic aging. Generally, the improvement in the condition and/or aesthetic appearance is selected from the group consisting of: reducing dermatological signs of chronological aging, photo-aging, hormonal aging, and/or actinic aging; preventing and/or reducing the appearance of lines and/or wrinkles; reducing the noticeability of facial lines and wrinkles, facial wrinkles on the cheeks, forehead, perpendicular wrinkles between the eyes, horizontal wrinkles above the eyes, and around the mouth, marionette lines, and particularly deep wrinkles or creases; preventing, reducing, and/or diminishing the appearance and/or depth of lines and/or wrinkles; improving the appearance of suborbital lines and/or periorbital lines; reducing the appearance of crow's feet; rejuvenating and/or revitalizing skin, particularly aging skin; reducing skin fragility; preventing and/or reversing of loss of glycosaminoglycans and/or collagen; ameliorating the effects of estrogen imbalance; preventing skin atrophy; preventing, reducing, and/or treating hyperpigmentation; minimizing skin discoloration; improving skin tone, radiance, clarity and/or tautness; preventing, reducing, and/or ameliorating skin sagging; improving skin firmness, plumpness, suppleness and/or softness; improving procollagen and/or collagen production; improving skin texture and/or promoting retexturization; improving skin barrier repair and/or function; improving the appearance of skin contours; restoring skin luster and/or brightness; minimizing dermatological signs of fatigue and/or stress; resisting environmental stress; replenishing ingredients in the skin decreased by aging and/or menopause; improving communication among skin cells; increasing cell proliferation and/or multiplication; increasing skin cell metabolism decreased by aging and/or menopause; retarding cellular aging; improving skin moisturization; enhancing skin thickness; increasing skin elasticity and/or resiliency; enhancing exfoliation; improving microcirculation; decreasing and/or preventing cellulite formation; and any combinations thereof. Without wishing to be bound by any particular theory, it is believed that the compositions of the present invention enhance and improve the aesthetic appearance of skin by stimulation of collagen and/or by improving the cell-to-cell adhesion between keratinocytes through the stimulation of Desmogleins. The composition will typically be applied to the skin one, two, or three times daily for as long as is necessary to achieve desired anti-aging results. The treatment regiment may comprise daily application for at least one week, at least two weeks, at least four weeks, at least eight weeks, or at least twelve weeks. Chronic treatment regimens are also contemplated. The N-substituted sulfonyloxybenzylamine active component is topically applied to an “individual in need thereof,” by which is meant an individual that stands to benefits from reducing visible signs of skin damage or aging. In a specific embodiment, the N-substituted sulfonyloxybenzylamine component is provided in a pharmaceutically, physiologically, cosmetically, and dermatologically-acceptable vehicle, diluent, or carrier, where the composition is topically applied to an affected area of skin and left to remain on the affected area in an amount effective for improving the condition and aesthetic appearance of skin. In one embodiment, methods for treating fine lines and wrinkles comprise topically applying the inventive N-substituted sulfonyloxybenzylamine compositions to the skin of an individual in need thereof, e.g., topically application directly to the fine line and/or wrinkle in an amount and for a time sufficient to reduce the severity of the fine lines and/or wrinkles or to prevent or inhibit the formation of new fine lines and/or wrinkles. The effect of a composition on the formation or appearance of fine lines and wrinkles can be evaluated qualitatively, e.g., by visual inspection, or quantitatively, e.g., by microscopic or computer assisted measurements of wrinkle morphology (e.g., the number, depth, length, area, volume and/or width of wrinkles per unit area of skin). This embodiment includes treatment of wrinkles on the skin of the hands, arms, legs, neck, chest, and face, including the forehead, It is also contemplated that the compositions of the invention will be useful for treating thin skin by topically applying the composition to thin skin of an individual in need thereof. “Thin skin” is intended to include skin that is thinned due to chronological aging, menopause, or photo-damage. In some embodiments, the treatment is for thin skin in men, whereas other embodiments treat thin skin in women, pre-menopausal or post-menopausal, as it is believed that skin thins differently with age in men and women, and in particular in women at different stages of life. The method of the invention may be employed prophylactically to forestall aging including in patients that have not manifested signs of skin aging, most commonly in individuals under 25 years of age. The method may also reverse or treat signs of aging once manifested as is common in patients over 25 years of age. The following examples are meant to demonstrate certain aspects of the invention in a non-limiting fashion. EXAMPLES Example 1 Collagen Assay Human dermal fibroblasts (Cascade Biologics, Portland, Oreg.) were plated at 10,000 cells/well in 96-well culture plates in supplemented medium (DMEM, 10% Fetal Bovine Serum, 1% Penicillin/Streptomycin and 1% L-Glutamine) overnight in humidified atmosphere of 10% CO 2 at 37° C. The next day, the medium was replaced with fresh medium (DMEM, 1% Penicillin/Streptomycin and 1% L-Glutamine) and the compounds dissolved in DMSO were added to the wells in triplicate at a concentration of 0.0005%. DMSO solution was used a control. Following 48-hour incubation, the plates were removed from the incubator and the medium from each well was collected for the procollagen assay. Collagen production was measured using procollagen type I C-peptide (PIP) EIA kit (Takara Bio, Inc., Japan). Briefly, the conditioned medium was diluted 1:10 in Sample Diluent. 20 μl of diluted conditioned medium and 100 μl of antibody-POD conjugate solution were added to the wells of the Takara ELISA plate. The ELISA plate was incubated at 37° C. for 3 hours before the wells were washed four times with 400 μl of 1×PBS. At the end of wash, 100 μl of substrate solution (supplied with kit) was added to the wells and incubated at room temperature for 15 minutes. The reaction was stopped by adding 100 μl of 1N sulfuric acid to the wells. The absorbance was measured on a spectrophotometer at 450 nm wavelength. The amount of procollagen peptide in the conditioned medium was calculated from the standard curve. The stimulation of collagen production was shown as an increase in collagen over the control. The results of compounds tested in the collagen assay are illustrated in Table 1: TABLE 1 Analogs active at stimulating collagen synthesis Stimulation Com- of pound collagen Number Position R 1 R 2 R 3 production* 1 4 CH 3 i-butyl SO 2 Phenyl ++++ 2 4 CH 3 i-butyl CONH(2-Et)Ph ++++ 3 3 CH 2 CH 3 CH 2 -2- CONH-c-hexyl +++ furanyl 4 3 CH 2 CH 3 s-butyl CO(4-OCH 3 )Ph +++ 5 3 CH 3 Methoxy- CO(4-C1)Ph +++ ethyl 6 3 CH 3 i-butyl CObutyl +++ 7 3 CH(CH 3 ) 2 i-butyl CO-i-butyl ++++ 8 4 CH 2 CH 3 i-butyl CO-c-propyl ++++ 9 3 CH 2 CH 3 i-propyl CONH-t-butyl +++ 10 3 CH(CH 3 ) 2 i-butyl CO-c-butyl +++ “+++”: 51-80% increase in collagen over control; “++++”: >81% increase in collagen over control All references including patent applications and publications cited herein are incorporated herein by reference in their entirety and for all purposes to the same extent as if each individual publication or patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety for all purposes. Many modifications and variations of this invention can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. The specific embodiments described herein are offered by way of example only, and the invention is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled.

4y

BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates to a carbon dioxide recovery system for removing and recovering carbon dioxide contained in a combustion exhaust gas of a boiler in a thermal power plant, a power generation system using the carbon dioxide recovery system, and a method for these systems. 2. Background Art In a power generation system of a thermal power plant using a large amount of fossil fuel, an amine absorption method is adopted as a method for removing and recovering carbon dioxide (CO 2 ) which is one of the causes of global warming. The amine absorption method has a problem that the large energy consumption at the time of separating and recovering CO 2 from a loaded absorption liquid with CO 2 absorbed therein significantly lowers the power generation output. For example, in Japanese Patent Laid-Open No. 3-193116, as shown in FIG. 4A , there is proposed a configuration in which a reboiler 41 is provided for a tower bottom part of a regeneration tower 24 for regenerating a loaded absorption liquid with CO 2 absorbed therein, and in which high pressure steam of about 3 kg/cm 2 absolute pressure is extracted from a low pressure turbine 8 and is supplied to the reboiler 41 provided for the bottom part of the regeneration tower as a heating source. This enables the loaded absorption liquid of the tower bottom part to be heated to an absorption liquid regeneration temperature of about 110 to 130° C., and hence, CO 2 in the loaded absorption liquid is separated so that the absorption liquid is regenerated. However, when all thermal energy required for the reboiler 41 of the tower bottom part is supplemented by the steam extracted from the low pressure turbine 8 , the amount of the steam extracted from the low pressure turbine 8 becomes large, which causes a problem that the output of the low pressure turbine 8 is significantly lowered and the power generation output is reduced. SUMMARY OF THE INVENTION Therefore, in view of the above described problem, it is an object of the present invention to provide a carbon dioxide recovery system capable of preventing reduction in turbine output at the time of regenerating the absorption liquid with carbon dioxide absorbed therein, a power generation system using the carbon dioxide recovery system, and a method for these systems. In order to achieve the above described object, according to the present invention, there is provided a carbon dioxide recovery system comprising: a turbine which is driven and rotated by steam; a boiler which generates the steam supplied to the turbine; a carbon dioxide absorption tower which absorbs and removes carbon dioxide from a combustion exhaust gas of the boiler by an absorption liquid; and a regeneration tower which heats and regenerates a loaded adsorption liquid with carbon dioxide absorbed therein, the carbon dioxide recovery system being characterized in that the regeneration tower is provided with plural loaded adsorption liquid heating means in multiple stages, which heat the loaded adsorption liquid and remove carbon dioxide in the loaded adsorption liquid, in that the turbine is provided with plural lines which extract plural kinds of steam with different pressures from the turbine and which supply the extracted plural kinds of steam to the plural loaded adsorption liquid heating means as their heating sources, and in that the plural lines are connected to make the pressure of supplied steam increased from a preceding stage of the plural loaded adsorption liquid heating means to a post stage of the plural loaded adsorption liquid heating means. As a variant, according to the present invention, there is provided a power generation system characterized by including the above described carbon dioxide recovery system and a generator which generates electric power by the rotation of the turbine. Further, as a variant, according to the present invention, there is provided a method for recovering carbon dioxide characterized by including the steps of: generating steam by a boiler; supplying the steam to a turbine; extracting plural kinds of steam with different pressures from the turbine; absorbing and removing carbon dioxide by an absorption liquid from a combustion exhaust gas of the boiler; and removing carbon dioxide in a loaded absorption liquid and regenerating the absorption liquid by heating the loaded absorption liquid which absorbs the carbon dioxide with successive use of the plural kinds of steam from the steam with lower pressure. Further, as a variant, according to the present invention, there is provided a power generation method characterized by including each step of the method for recovering carbon dioxide, and a step of generating electric power by the rotation of the turbine from which the plural kinds of steam with different pressures are extracted. In the case of the regeneration tower in which the loaded absorption liquid heating means (reboiler) is provided only for the tower bottom part, as shown in FIG. 4B , the temperature of the loaded absorption liquid in the regeneration tower has a distribution formed in such a manner that the temperature is gradually raised from the tower top part to near the tower bottom part and is abruptly raised to the absorption liquid regeneration temperature in the tower bottom part. Thus, according to the present invention, there is provided a configuration in which plural loaded absorption liquid heating means are provided for the regeneration tower in multiple stages, and in which when plural kinds of steam with different pressures are extracted from the turbine and supplied to the plural loaded absorption liquid heating means as their heating sources, the pressure of supplied steam is arranged to be increased from a preceding stage of the plural loaded absorption liquid heating means to a post stage of the plural loaded absorption liquid heating means. As a result, by utilizing the steam with the pressure lower than the pressure of the steam supplied to the loaded absorption liquid heating means of the post stage (tower bottom part), the temperature of the loaded absorption liquid can be increased while the loaded absorption liquid flows down to the tower bottom part in the loaded absorption liquid heating means of the preceding stage. Thereby, the amount of high pressure steam required for heating the loaded absorption liquid by the loaded absorption liquid heating means of the post stage (tower bottom part) can be reduced. Therefore, a part of the high pressure steam extracted from the turbine can be replaced with the steam with the lower pressure, so that it is possible to suppress the reduction in turbine output due to the steam extraction. Further, the power generation system according to the present invention is configured to comprise the above described carbon dioxide recovery system, and a generator which generates electric power by the rotation of the turbine. Thus, as described above, the reduction in turbine output can be suppressed and thereby power generation output of the generator can be improved. Further, according to the present invention, the method for recovering carbon dioxide is configured to extract plural kinds of steam with different pressures from the turbine, and to heat the loaded absorption liquid with successive use of the plural kinds of steam with different pressures from the steam with lower pressure. Thus, as described above, it is possible to eventually reduce the amount of the high pressure steam for heating and regenerating the loaded absorption liquid. As a result, a part of the high pressure steam extracted from the turbine can be replaced with the steam with lower pressure, so that it is possible to suppress the reduction in turbine output due to the steam extraction. Further, according to the present invention, the power generation method is configured by comprising each step of the above described method for recovering carbon dioxide, and a step of generating electric power by the rotation of the turbine from which the plural kinds of steam with different pressures are extracted. Thus, as described above, the reduction in turbine output can be suppressed and thereby power generation output of the generator can be improved. As described above, according to the present invention, it is possible to provide a carbon dioxide recovery system capable of preventing the reduction in turbine output at the time of regenerating the absorption liquid with carbon dioxide absorbed therein, and a power generation system using the carbon dioxide recovery system, and a method for these systems. In the following, an embodiment according to the present invention is described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic illustration of an embodiment of a carbon dioxide recovery type power generation system according to the present invention; FIG. 2 is a schematic illustration of an internal structure of a regeneration tower in FIG. 1 ; FIG. 3 is a schematic illustration of another embodiment of the carbon dioxide recovery type power generation system according to the present invention; and FIG. 4A is a schematic illustration of a structure in the vicinity of a regeneration tower of a conventional carbon dioxide recovery type power generation system; and FIG. 4B is a graph showing a temperature distribution in the regeneration tower. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT It is noted that in the accompanying drawings, only main facilities are shown and accessory facilities are omitted. In the drawings, tanks, bulbs, pumps, blowers and heat exchangers are provided as required. Further, two turbines are usually provided in pairs as each of a low pressure turbine, a medium pressure turbine and a high pressure turbine, but each pair of the turbines is also represented by a single reference numeral. As shown in FIG. 1 , the carbon dioxide recovery type power generation system according to the present invention comprises a boiler 1 having a reheating unit 5 , a high pressure turbine 3 which is driven by steam of the boiler 1 , a medium pressure turbine 7 which is driven by steam discharged from the high pressure turbine 3 and heated by the reheating unit 5 , a low pressure turbine 8 which is driven by steam discharged from the medium pressure turbine 7 , and a generator 13 which generates electric power by the rotation of these turbines. The exhaust side of the low pressure turbine 8 is connected to the boiler 1 via a line 11 provided with a condenser 10 which condenses the exhaust, and an overhead condenser 25 which effects heat exchange between condensed water and recovered CO 2 , in this sequence. Further, on the combustion exhaust gas outlet side of the boiler 1 , a blasting blower 14 which pressurizes of a combustion exhaust gas, a cooler 15 which cools the combustion exhaust gas, and a CO 2 absorption tower 18 which is filled with CO 2 absorption liquid for absorbing and removing CO 2 from the combustion exhaust gas are successively arranged in this sequence from the side of the boiler. It is noted that as the CO 2 absorption liquid, an alkanolamine such as, for example, monoethanolamine, diethanolamine, triethanolamine, methyldiethanolamine, diisopropanolamine, diglycolamine, is preferred, and an aqueous solution of one of these compositions or an aqueous solution obtained by mixing two or more of these compositions can be used. The CO 2 absorption tower 18 is installed in combination with a regeneration tower 24 which regenerates the loaded adsorption liquid with CO 2 absorbed therein. These towers are connected by a line 20 which supplies the loaded absorption liquid to the regeneration tower 24 , and by a line 19 which supplies a reproduced adsorption liquid to the CO 2 absorption tower 18 . A rich/lean solvent heat exchanger 23 which effects heat exchange between the line 20 and the line 19 is provided for the line 20 and the line 19 . Further, a lean solvent cooler 33 which further cools the regenerated adsorption liquid is provided for the line 19 between the CO 2 absorption tower 18 and the heat exchanger 23 . In the regeneration tower 24 , as shown in FIG. 2 , a nozzle 56 for spraying the loaded adsorption liquid downward from the line 20 is provided. Underneath the nozzle 56 , a lower filling section 52 filled with a filler is provided in order to make the sprayed loaded adsorption liquid easily brought into contact with steam. Further, above the nozzle 56 , an upper filling section 51 filled with a filler is provided in order to remove adsorption liquid steam and mist. A first reboiler 41 for heating the loaded absorption liquid is provided for a bottom part of the regeneration tower 24 . The first reboiler 41 and the regeneration tower 24 are connected by a line 47 , which leads the loaded adsorption liquid stored in the tower bottom part to be heated by the first reboiler and then returns the heated absorption liquid again to the tower bottom part. Further, the first reboiler 41 and the low pressure turbine 8 are connected by a line 44 which supplies steam extracted from the low pressure turbine 8 as a heating source of the first reboiler 41 . Further, in the regeneration tower 24 , a liquid storage section 61 for storing the loaded adsorption liquid which flows down is provided between the nozzle 56 and the tower bottom part. Thus, the lower filling section 52 is vertically divided into two parts which are positioned above and below the liquid storage section 61 . Further, a second reboiler 42 for heating the loaded adsorption liquid is provided for a preceding stage of the first reboiler 41 . The second reboiler 42 and the regeneration tower 24 is connected by a line 48 , which leads the loaded adsorption liquid stored in the liquid storage section 61 to be heated by the second reboiler and then returns to the lower part of the liquid storage section 61 . Further, the second reboiler 42 and the low pressure turbine 8 are connected by a line 45 which supplies, as a heating source of the second reboiler 42 , steam with a pressure lower than the pressure of the steam which is extracted to be supplied to the first reboiler 41 . It is noted that a nozzle 58 for spraying the heated loaded adsorption liquid downward is provided for the line 48 . Further, a vent hole 62 for allowing CO 2 gas ascending from the lower part of the tower to pass upward is provided for the liquid storage section 61 . Above the vent hole 62 , there is provided a top plate 63 for preventing the loaded adsorption liquid, which flows down from the upper part of the tower, from passing to the lower part of the tower. Further, a line 28 is provided for the CO 2 gas outlet side of the tower top part of the regeneration tower 24 , the line 28 being successively provided with an overhead condenser 25 for effecting heat exchange between CO 2 gas and condensed water, an overhead cooler 26 for cooling CO 2 gas, and a separator 27 for separating water content from CO 2 gas, in this sequence. In addition, a line 30 which supplies the water separated by the separator 27 again to the tower top part of the regeneration tower 24 is provided for the separator 27 . A nozzle 57 for spraying the reflux water downward is provided for the line 30 . With the above configuration, steam which is generated and heated to a high pressure and a high temperature (of about 250 kg/cm 2 G, about 600° C.) by the boiler 1 is introduced into the high pressure turbine 3 via a line 2 to drive the high pressure turbine 3 . Steam (of about 40 kg/cm 2 G, about 300° C.) discharged from the high pressure turbine via a line 4 is heated by the reheating unit 5 in the boiler 1 . The steam discharged from the high pressure turbine which is reheated (to about 600° C.), is introduced into the intermediate pressure turbine 7 via a line 6 , to drive the medium pressure turbine 7 . Steam (of about 10 kg/cm 2 G) discharged from the intermediate pressure turbine is introduced into the low pressure turbine 8 via a line 9 to drive the low pressure turbine 8 . In this way, the turbines are driven to enable the generator 13 to generate electric power. Further, a part of the steam is extracted from the low pressure turbine and supplied via the line 44 to the first reboiler 41 provided for the tower bottom part. Further, a part of steam with a pressure lower than the pressure of the steam supplied to the first reboiler is extracted from the low pressure turbine and supplied to the second reboiler 42 via the line 45 . The two kinds of extracted steam are respectively used to heat the loaded absorption liquid in the first reboiler 41 and the second reboiler 42 , so as to be condensed. Further, the two kinds of extracted steam are pressurized by a reboiler condensate pump 32 , and then mixed with boiler feed water of the line 11 . Thereby, the boiler feed water is heated up and transferred to the boiler 1 . Here, the steam which is extracted to be supplied to the first reboiler 41 provided for the tower bottom part, preferably has a temperature which makes it possible to remove almost all CO 2 from the loaded absorption liquid to regenerate the absorption liquid, and which for example preferably ranges from 130 to 160° C., although the temperature may be different depending upon the kinds of CO 2 absorption liquid. It is noted that the absolute pressure of the steam corresponding to this temperature ranges from 2.75 to 6.31 ata. Further, the steam which is extracted to be supplied to the second reboiler 42 preferably has a temperature lower than the above described temperature, that is, an absolute pressure lower than the above described absolute pressure, in order to heat the loaded absorption liquid in stages. It is noted that when supplied into the regeneration tower 24 , the loaded absorption liquid is depressurized to release a part of CO 2 and cooled (for example, by a temperature about 20° C.). Therefore, the lower limit value of the steam is preferably set to a temperature which makes it possible to effect heat exchange with the absorption liquid with the temperature when it is introduced into the tower (for example, a temperature higher by about 10° C. compared with the temperature of the absorption liquid after it is introduced into the tower, or a temperature lower by about 10° C. compared with the temperature of the absorption liquid when it is supplied to the tower), that is, preferably set to an absolute pressure corresponding to the steam temperature. The exhaust (of about 0.05 ata, about 33° C.) of the low pressure turbine 8 is introduced into the condenser 10 via the line 11 and condensed. A boiler feed pump 12 makes the condensed water preheated through the overhead condenser 25 and then transferred to the boiler 1 as the boiler feed water. On the other hand, the boiler combustion exhaust gas containing CO 2 discharged from the boiler 1 is first pressurized by the blasting blower 14 , and then transferred to the cooler 15 so as to be cooled by cooling water 16 . The cooled combustion exhaust gas is transferred to the CO 2 absorption tower 18 , and cooling wastewater 17 is discharged to the outside of the system. In the CO 2 absorption tower 18 , the combustion exhaust gas is brought into contact in counterflow with CO 2 absorption liquid based on the alkanolamine, so that CO 2 in the combustion exhaust gas is absorbed by the CO 2 absorption liquid through a chemical reaction. The combustion exhaust gas 21 with CO 2 removed therefrom is discharged from the tower top part to the outside of the system. The loaded absorption liquid (rich absorption liquid) with CO 2 absorbed therein is pressurized by a rich solvent pump 22 via the line 20 connected to the tower bottom part, and heated by the rich/lean solvent heat exchanger 23 , and thereafter is supplied to the regeneration tower 24 . In the regeneration tower 24 , the loaded absorption liquid is sprayed from the nozzle 56 , and flows downward through the lower filling section 52 B so as to be stored in the liquid storage section 61 . Then, the loaded absorption liquid in the liquid storage section 61 is extracted by the line 48 , and heated by the low pressure steam of the line 45 in the second reboiler 42 , and thereafter returned again to the regeneration tower 24 . The loaded absorption liquid thus heated is sprayed by the nozzle 58 , and a CO 2 gas partially separated from the absorption liquid by the heating operation ascends upward in the tower as shown by a dotted line in FIG. 2 , while the loaded absorption liquid still containing CO 2 flows down in the tower. Further, the loaded absorption liquid, which passes through the lower filling section 52 A and is stored in the tower bottom part, is extracted by the line 47 to be heated by the higher pressure steam of the line 44 in the first reboiler 41 , and thereafter is returned again to the tower bottom part. The residual CO 2 is almost separated from the absorption liquid by this heating operation in the first reboiler 41 of the tower bottom part. The separated CO 2 gas ascends in the tower in the same way as described above. The CO 2 gas which ascends in the tower is discharged from the tower top part of the regeneration tower 24 . The discharged CO 2 gas passes through the line 28 , to preheat the boiler feed water of the line 11 in the overhead condenser 25 , and is further cooled by the overhead cooler 26 . Thereby, the water content in the CO 2 gas is condensed. The condensed water is removed by the separator 27 . The high purity CO 2 gas with water content removed therefrom is discharged to the outside of the power generation system, so as to be able to be used effectively for other applications. Further, the condensed water separated by the separator 27 is refluxed by a condensed water circulation pump 29 into the regeneration tower 24 through the line 30 . The reflux water is sprayed by the nozzle 57 to wash CO 2 gas ascending through the upper filling section 51 , thereby making it possible to prevent the amine compound contained in the CO 2 gas from being discharged from the tower top part. On the other hand, almost all CO 2 is separated from the loaded absorption liquid by the heating operation in the first reboiler of the tower bottom part, so that the absorption liquid is regenerated. The regenerated absorption liquid (lean absorption liquid) is extracted by the line 19 , and pressurized by a lean solvent pump 31 . Then, the regenerated absorption liquid is cooled by the loaded absorption liquid in the rich/lean solvent heat exchanger 23 and is further cooled by the lean solvent cooler 33 so as subsequently to be supplied to the CO 2 absorption tower 18 . Thus, the CO 2 absorption liquid can be used in circulation in the power generation system. In this way, high pressure steam is extracted from the low pressure turbine 8 as a heating source of the first reboiler 41 of the tower bottom part, and steam with a pressure lower than the pressure of the high pressure steam is extracted from the low pressure turbine 8 as a heating source of the second reboiler 42 between the nozzle 56 and the tower bottom part, as a result of which the loaded absorption liquid can be heated in stages by the steam extracted in the two stages. Thus, instead of a part of the high pressure steam extracted from the low pressure turbine 8 , which part is to be supplied to the first reboiler 41 of the tower bottom part, steam with a lower pressure can be extracted from the low pressure turbine 8 , as a result of which output decrease of the low pressure turbine 8 can be suppressed as a whole and power generation output of the generator 13 can be improved. It is noted that in FIG. 1 and FIG. 2 , the reboiler is constituted in two stages by providing the second reboiler 42 between the nozzle 56 and the tower bottom part so as to extract steam from the low pressure turbine 8 in two stages. However, the reboiler provided for the regeneration tower 24 may be constituted in three or more stages to extract steam from the low pressure turbine 8 in three or more stages. In this case, the line which supplies the extracted steam to the reboiler is connected so as to make the pressure of supplied steam increased from the reboiler in the preceding stage of the regeneration tower 24 (the tower top part side) to the reboiler in the post stage of the regeneration tower 24 (the tower bottom part side). For example, as shown in FIG. 3 , a liquid storage section 66 , a vent hole 67 and a top plate 68 are additionally provided between the nozzle 56 and the liquid storage section 61 , and a third reboiler 43 is also provided in the preceding stage of the second reboiler 42 , so that steam with a pressure further lower than the pressure of the steam supplied to the second reboiler 42 is extracted from the low pressure turbine 8 and is supplied to the third reboiler 43 via a line 46 . Thereby, the loaded absorption liquid in the added liquid storage section 66 is heated by the third reboiler 43 via a line 49 . As a result, the loaded absorption liquid in the regeneration tower 24 can be heated in more stages. Therefore, instead of a part of the high pressure steam supplied to the first reboiler 41 and the second reboiler 42 , the steam with further lower pressure is extracted from the low pressure turbine 8 , so that output decrease of the low pressure turbine 8 can be further suppressed. EXAMPLE A rich absorption liquid with CO 2 absorbed therein is regenerated by using a steam system consisting of the regeneration tower and the low pressure turbine shown in FIG. 3 . The result is shown in Table 1. Further, a result of the case where the steam system consisting of the conventional regeneration tower and the low pressure turbine shown in FIG. 4 is used, is also shown in Table 1 as a comparison example. TABLE 1 CONVENTIONAL PRESENT SYSTEM INVENTION (FIG. 4) (FIG. 3) CO 2 RECOVERY AMOUNT 324 ton/h 324 ton/h REBOILER INPUT HEAT 242.41 Gcal/h 243.02 Gcal/h AMOUNT REBOILER FIRST 417 ton/h 174 ton/h INPUT STEAM REBOILER (3.6 ata) (3.6 ata) AMOUNT SECOND — 138 ton/h (ABSOLUTE REBOILER (3.16 ata) PRESSURE) THIRD — 107 ton/h REBOILER (2.73 ata) TURBINE OUTPUT DECREASE 76,330 W 73,756 kW DUE TO EXTRACTION OF (100) (96.6) STEAM SUPPLIED TO REBOILER (CONVENTIONAL CASE: 100) RICH ABSORPTION LIQUID 3824 ton/h 3824 ton/h SUPPLY AMOUNT LEAN ABSORPTION LIQUID 3500 ton/h 3500 ton/h DISCHARGE AMOUNT REGENERATION TOWER 112° C. 112° C. INLET TEMPERATURE OF RICH ABSORPTION LIQUID REGENERATION TOWER 120° C. 120° C. OUTLET TEMPERATURE OF LEAN ABSORPTION LIQUID As shown in Table 1, in the conventional system, it is necessary to supply high pressure steam of 3.6 ata to the reboiler of the tower bottom part at a rate of 417 ton/h, in order to make the rich absorption liquid of a predetermined amount heated to 120° C. and regenerated. As a result, the output of the low pressure turbine from which the steam is extracted, is lowered by 76,330 kW. On the other hand, in the system according to the present invention shown in FIG. 3 , steam with a lower pressure of 2.73 ata and steam with a lower pressure of 3.16 ata are supplied to the third reboiler and the second reboiler at a rate of 107 ton/h and at a rate of 138 ton/h, respectively, so that even when the rate of the high pressure steam of 3.6 ata supplied to the first reboiler of the tower bottom part is reduced to 174 ton/h, the rich absorption liquid can be regenerated similarly to the conventional system. Therefore, the total amount of heat supplied to the first to third reboilers is approximately equal to the amount of heat supplied to the reboiler of the tower bottom part in the conventional system, but the output of the low pressure turbine is lowered only by 73,756 kW. As a result, the turbine output can be improved by about 3.4% in comparison with the conventional system.

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BACKGROUND OF THE INVENTION This invention relates to a method for processing large cast iron dies, particularly of the type used in the automobile industry for pressing sheet metal to form vehicle body parts. Such dies are usually constructed at the present time of alloy cast iron, which after casting is mechanically machined, this being followed in most cases by surface hardening of those regions of the die which are subjected to maximum wear when in use. Specifically, the purpose of the surface hardening is to harden these die regions in order to increase their wear resistance, which is known to depend on the surface hardness, so increasing the life of the entire die and obviating the need to take costly action to restore its initial geometry, with consequent production loss. However, flame hardening has numerous drawbacks: it is of slow implementtion and cannot be automated due to the fact that because of its nature it cannot be easily parameterized, and therefore has to be executed manually by specialised operators; moreover, whatever the ability of these latter it does not produce uniform results in terms of hardness and depth of hardening, and can give rise to cracks in the die with consequent need for repair; on the other hand, the replacement of flame hardening by other analogous surface hardening treatments such as induction or by treatment with a laser beam has not so far been possible, as the complicated shapes of the dies inevitably result in superimposing of more than one hardening treatment in certain regions of the die, with the consequent formation of cracks. Finally, known flame-hardened dies have the drawback of being subject to seizure when in use, this being the cause of many pressing rejects and the need for considerable lubrication, and in addition results in frequent and costly down-times of the presses equipped with such dies. SUMMARY OF THE INVENTION An object of the invention is to provide a method for processing large cast iron dies, in particular those used for vehicle sheet-metal pressing, which obviates the need for flame-hardening while ensuring an acceptable die life; a further object is to provide dies which when in use are able to reduce lubricant consumption and/or reduce or eliminate rejects and machine down-times due to seizure. Said objects are attained according to the invention by a method for processing large cast iron dies, particularly for sheet-metal pressing for vehicle construction, characterised in that in those die regions which are most subject to wear in relation to the specific use of the die, this latter is subjected to localised heating beyond the austenization temperature by the application of a laser beam which is transferred along said regions by moving it in such a manner that it always remains orthogonal to the surface of said regions so as to rigorously follow their profile; said heating being effected by means of a laser beam focusing head having five capabilities of movement and with such parameters as to produce in correspondence with said die regions a localised martensitic transformation to a depth of at least 1 mm and a surface hardness exceeding 400 HB. In practice, the applicant has surprisingly found that by operating in a suitable manner it is possible to apply laser treatment of such an intensity as to produce known surface hardening in cast iron for automobile use in place of the costly, slow and unsatisfactory flame-hardening, without the occurrence, which common opinion has up to the present time considered inevitable, of cracks in those die regions in which more than one successive hardening treatment has been superimposed because of the die geometry. By virtue of this advantageous method of operation, which consists substantially of moving the laser beam focusing head, by which the treatment is carried out, in such a manner that the laser beam always strikes the region to be treated rigorously perpendicular to the surface thereof, ie such that the focusing head movements rigorously follow the profile of the region to be treated however this profile may be, a uniform and considerable increase in the surface hardness of the die is obtained precisely in those regions subject to most wear, with a consequent longer die life than known dies, together with a lower cost and increased speed of treatment. Moreover, as laser hardening is an operation which can be parameterized, it is possible to automate the hardening operation, provided it is carried out by robots able to move the fousing head in the required manner at a rigorously constant distance from the treated surfaces, while at the same time enabling the focusing head to continuously receive the laser beam from the emission source which, in the current state of the art, is known to be of such dimensions and weight for high power emission as to prevent it from undergoing any movement, and is thereore fixed. However the most surprising result of the method of operation according to the invention, and which was completely unexpected and unforseeable, consists of the fact that those cast iron dies which have undergone laser treatment in which the beam strikes precisely orthogonally those die regions in which wear is mostly localised during use, have shown an operational behaviour which is decidedly superior and surprising, with the almost total disappearance of seizure during the sheet-metal working, which drastically reduces machine down-times during use. This unexpected behaviour of dies constructed in accordance with the method of the invention is usually also accompanied by a drastic reduction in the need for die lubrication during the sheet-metal pressing, and this is even more apparent if during the die construction, particular methods of applying the laser beam are combined with particular types of cast iron. In particular, various types of cast iron of lamellar structure have been widely tested, such as G190, G210 and Gh P (in accordance with Italian Standards denominations), very positive results having been obtained without the appearance of cracks and without melting the metal, and with hardness increases which exceed even twice the initial hardness. By extrapolating the results obtained, it would be logical to suppose that the same positive results would also be obtainable operating with cast irons of different type, such as pearlite or Meehanite, which are known to be better hardenable than those tested and for which even better results would therefore be expected. The laser hardening of such cast irons is implemented according to the invention by a machine numerically controlled along five axes and provided with said focusing head, a laser source and a suitable reflecting mirror system, as will be described hereinafter; the mirrors are of copper construction and are cooled internally by water circulation, and the incident laser beam is made to move over the surface of the region to be treated at constant speed (of the order of 0.3-0.5 m/min) along rectilinear or curved trajectories and in a single predetermined direction along each trajectory, its angle of incidence to the surface of the treated region being always normal to said surface; the laser source used is preferably of the carbon dioxide type and consists of a commercial laser cavity of about 5 kW power, with vacuum gas circulation and arc excitation; preferably, a laser cavity of the "Spectra Physics Model 975" (registered trademark) is used, capable of generating a laser beam of 10.6 micrometers (microns) wavelength, of 44 mm diameter and having a maximum divergence of about 3 milliradians. Of the dies according to the invention, which are of conventional construction by casting followed by possible mechanical machining, those parts which are most suitable for laser hardening treatment, and at the same time giving the best overall results in terms of greater overall die efficiency, are the blank holder rings, which are usually the components which most suffer the effects of wear during sheet-metal pressing. After heating to beyond the austenization temperature by the laser beam, quenching is effected according to the invention in air by free cooling to ambient temperature after heating. Because of the extreme localisation of laser heating there is substantially no heat dispersion during the heating stage, so that as soon as the laser beam ceases to strike the treated surface, either because of its withdrawal therefrom or because of beam suppression, the region lying immediately below this surface is cooled more or less instantaneously by conduction, the heat accumulated therein being dispersed into the cold mass of the treated component from which it is then transferred into the environment by convection. It is therefore not necessary to use water cooling, and in fact extremely drastic quenching is obtained with a cooling rate much greater than the rate obtainable even by the most drastic water quenching, all without the minimum risk of cracking, even in materials such as cast irons of lamellar structure which whenusing other treatment (such as flame-hardening) are particularly difficult to treat without damage. Finally, in order to obtain the described surprising results during the use of dies constructed in accordance with the invention, it has been found absolutely necessary to conduct the hardening treatment by operating the laser in such a manner as to obtain in the treated regions a localised martensitic transformation to a depth of at least 1 mm and a surface hardness exceeding 400 HB (Brinell number). These parameters are critical, and on the basis of these any expert of the art is able to calculate, using the known mathematical and empirical correlations, those physical and electrical parameters which need to be set for any type of laser of known power. If noduclar cast iron is used for the construction of the die or of those regions thereof to be laser-treated, the cast iron is surface-metallized after hardening, preferably with chromium. BRIEF DESCRIPTION OF THE DRAWING The present invention is described hereinafter in terms of a non-limiting emodiment with reference to the accompanying drawing, which shows the machine necessary for implementing the method of the invention, and with reference to the subsequent experimental examples. DETAILED DESCRIPTION OF THE INVENTION In the said accompanying drawing, the reference numeral 1 indicates overall a numerically controlled machine or robot provided with a focusing head 2 for a laser beam 3 produced by a fixed source 4 consisting of any power laser cavity of any known type, not shown in detail for simplicity. The machine 1, which according to the invention is able to set the head 2 with precision at any point in space by offering it five capabilities of movement along five numerically controlled "axes", identified by the arrows and by the letters a, b, c, d and e, comprises a portal structure 5, an arm 6 carried by the structure 4 and projecting perpendicularly therefrom and mobile along a first "axis" or controlled direction a on respective guides 7 carried by an upper cross-member 8 of the structure 5, a carriage 10 carried laterally by and projecting from the arm 5 and mobile thereon on guides 11 along a second "axis" or controlled direction b perpendicular to the axis a, and a shaft or column 12 carried by the carriage 10 and mobile through this latter on suitable mechanisms of any known type, not shown for simplicity, for example of the screw/nut type, along its own axis so as to translate along a third "axis" or controlled direction c perpendicular to both the axes a and b. The head 2, of known type and not described in detail for simplicity, is carried angularly rigid by a turret 14 which is mounted rotatable about an axis parallel to the cross-member 8 and is therefore mobile along a fourth "axis" or controlled direction e, in the direction of the arrows. The turret 14 is carried offset from the axis of the shaft 12 in a cantilever manner by a connection piece 15, which is carried angularly rigid by the shaft 12, which besides being able to slide along the direction or axis c is also rotatable about is own axis of symmetry so as to be able to move the connection piece 15 and the turret 14 rigid therewith along a fifth "axis" or controlled direction d. The connection piece at is disposed eccentric to the axis of the shaft 12 and cantilevered on the opposite side to the turret (14), and is provided with an aperture 18 through which the beam 3 can enter the connection piece 15 and, by means of a pair of mirrors, not shown but of known type, carried internally by respective oblique faces 20 and 21 of the connection piece 15 and of the turret 14 respectively, be reflected in known manner through these to reach the head 2. The mirrors carried by the walls 20 and 21 are coaxial with the axis of rotation of the turret 14, and a pair of respective mirrors 22 and 23 constructed of copper in known manner and cooled internally by a water flow deviates the beam 3 from the source 4 to the aperture 18. In particular, according to the invention, the mirror 22 is carried rigidly by the arm 6 in proximity to the cross-member 8, whereas the mirror 23 projects from the side of the carriage 10. Both the mirrors 22, 23 are disposed obliquely at 45°. Finally, the machine 1 is completed by a support table 30 slidable on rails, not shown for simplicity, and on which the dies to be treated (or a part thereof) can be referenced and fixed, and by suitable known electronic control and reference devices, not shown for simplicity, for example consisting of an encoder for each "axis" or controlled direction, a suitable microprocessor unit, and suitable electric motors, preferably of the stepping type, arranged to move the arm 6, the carriage 10, the shaft 12 and the turret 14 in the rectilinear or curved directions a, b, c, d and e in a controlled manner. EXAMPLE I Using cast irons of different compositions, all of which fall within those listed in Table I, two test-pieces are prepared for each different type of cast iron. All the test-pieces are rectilinear, having dimensions of 40×100×100 mm, and a sectional shape identical to that of the blank holder rings of automobile dies, and are hardened by laser treatment followed by cooling in atmospheric air. A CO 2 laser source is used consisting of a 5 kW "Spectra Physics Model 975" (registered trademark) laser cavity fed with 30 amperes at 3000 volts and kept at 1 Torr, it being coupled to the machine or robot 1 heretofore described. Some test-pieces are treated with said laser source operating with known equipment, ie by directing the beam onto the regions to be treated using rotary mirrors without taking care to obtain a perpendicular strike, whereas others are treated using the machine 1 in the following manner: after positioning the head 2 over the required region by moving the arm 6 and carriage 10, the beam 3 is orientated perfectly perpendicular to the surface of the region to be treated, by modifying its attitude as the curvature of this region varies so as to rigorously follow its profile. This result is obtained, without the need to suppress the beam 3 during movement and without the need for auxiliary mirrors, by rotating the turret 14 and rotating the shaft 12, and simultaneously compensating the misalignment which is created following the rotation of the shaft 12 between the mirror 23 and aperture 18 by suitably moving the carriage 10 and the arm 6 from their initial position and simultaneously compensating any variations in height of the head 2 above the surface to be treated by vertically moving the shaft 12. It is apparent that any attempt without the aid of the machine 1 to keep the beam 3 perpendicular to the surface to be treated along its entire profile, if this is complicated, would result in loss of collimation of the beam 3 because of the inevitable relative movements between the deviating mirrors. The results obtained are given in Table II. TABLE I______________________________________Type of Chemical compositioncast iron C Si Mn Ni Cr P S______________________________________G190 3.0 1.9 0.6 -- -- <0.15 <0.12 3.1 2.0 0.7Gh P 3 1.65 0.8 -- 0.25 0.8 <0.12 1 0.40 1G210 2.6 1.25 0.6 2.25 0.75 <0.15 <0.12 3.5 2.25 1 2.50 1______________________________________ TABLE II______________________________________ thick-Test-piece cast air beam ness hardnessNo. iron quench perpend. cracks mm (HB)______________________________________1 190 yes no yes 0.85 3992 " yes yes no 1.19 4093 210 yes no yes 0.79 4304 " yes yes no 1.24 4505 Gh yes no yes 0.92 4086 " yes yes no 1.11 430______________________________________ EXAMPLE II Operating as in Example I and using the described apparatus 1, standard dies are prepared for producing the rear wheelhouse of an automobile, its blank holder rings being constructed of G190 cast iron having a composition as indicated in Table I. These dies are then used for sheet-metal pressing together with other similar dies of conventional construction, ie having manually flame-hardened blank holder rings of G210 cast iron construction. The operating results are given in Table III. TABLE III______________________________________Type of No. of pieces % to be % to be Stoppages duecast iron produced scrapped repaired to seizure______________________________________210 10,000 0.32 1.35 50flame-hardened190 10,000 0.05 0.64 2laser-hardened______________________________________ EXAMPLE III Operating as in Example II, standard dies are prepared for producing an automobile side member, its blank holder rings being constructed of Gh P cast iron having a composition as indicated in Table I, and quenched in air. These dies are then used for sheet-metal pressing together with other similar dies of conventional construction, ie having manually flame-hardened blank holder rings of G210 cast iron construction. The operating results are given in Table IV. TABLE IV______________________________________Type of No. of pieces % to be % to be Stoppages duecast iron produced scrapped repaired to seizure______________________________________210 10,000 0.95 1.30 40flame-hardenedGh P 10,000 0.21 0.6 1laser-hardened______________________________________ EXAMPLE IV Operating as in Example II, standard dies are prepared for producing the lower body side of an automobile, its blank holder rings being constructed of G210 NiCr alloy cast iron having a composition as indicated in Table I and quenched in air. These dies are then used for sheet-metal pressing together with other similar dies of conventional construction, ie having manually flame-hardened blank holder rings of G210 cast iron construction. The operating results are given in Table V. TABLE V______________________________________Type of No. of pieces % to be % to be Stoppages duecast iron produced scrapped repaired to seizure______________________________________210 2,500 3.65 2.89 9flame-hardened210 10,000 1.60 1.20 3laser-hardened______________________________________

4y

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of U.S. Provisional Application Ser. No. 60/979,551, filed Oct. 12, 2007, which is hereby incorporated by reference. FIELD OF THE INVENTION [0002] The present invention relates to an improved ceramic honeycomb particulate filter. In particular, the invention relates to honeycomb ceramic filters that have improved thermal shock resistance. BACKGROUND OF THE INVENTION [0003] Diesel engines, because of the way they operate, emit soot particles or very fine droplets of condensate or a conglomerate of the two (particulates) as well as typical harmful gasoline engine exhausts (i.e., HC and CO). These “particulates” (herein Diesel soot), are rich in condensed, polynuclear hydrocarbons, some of which may be carcinogenic. [0004] As the awareness of the danger Diesel soot presents to health collides with the need for greater fuel efficiency that Diesel engines provide, regulations have been enacted curbing the amount of Diesel soot permitted to be emitted. To meet these challenges, soot filters have been used. The filters have had many configurations as exemplified by GB 1,014,498 and U.S. Pat. No. 4,828,807. The most common and useful filters have tended to be porous ceramic honeycombs that have plugged channels such that the exhaust gas must enter a channel and pass through the wall of the channel as exemplified by U.S. Pat. No. 4,329,162. [0005] Early attempts to make more thermal shock resistant honeycombs, for example, for use in heat regenerators and catalytic converters focused on the use of ceramics having a low coefficient of thermal expansion, such as described in U.S. Pat. Nos. 4,304,585 and 4,598,054. Nevertheless the art is replete with methods of improving the shock resistance of ceramic honeycombs, for example by assembling smaller honeycombs with layers between the smaller honeycombs (i.e., segmented honeycombs). The layers are well known and have included all manner of ceramic cements, foamed or unfoamed, with differing additives such as ceramic or metal fibers, organic materials such as pore formers and binders. Exemplary patents include those previously mentioned and, for example, U.S. Pat. Nos. 3,251,403; 4,335,783; 4,381,815; 4,810,554; 4,953,627; 5,914,187 and 7,087,286. Unfortunately, all of these result in significantly greater forming complexity and increase in pressure drop, for example, when the honeycomb is used as a filter with inlet and outlet channels. [0006] Another method for increasing the thermal shock resistance of ceramic honeycombs include, for example, creating slits radially or axially in the honeycombs to make the honeycombs more compliant due to hoop and axial stresses, such as in U.S. Pat. Nos. 3,887,741 and 3,983,283. This method to increase the thermal shock resistance, unfortunately, tends to result in fragile honeycombs resulting in more handling damage during the manufacture and to complexity in forming the radial grooves. [0007] What is needed is a Diesel particulate filter that avoids one or more problems of the prior art such as one of the aforementioned problems. In particular, it would be desirable to provide a Diesel particulate filter that maximizes the effective filtration area while smoothing out temperature differences within the catalyst due to combustion of differing species along the length of the filter (i.e., more thermal shock resistant). It would also be desirable when doing so to minimize the pressure drop increase associated with other methods used to improve thermal shock of the honeycombs. SUMMARY OF THE INVENTION [0008] We have discovered an improved ceramic honeycomb structure that allows, for example, soot filters that maximize the effective filtration area (i.e., minimizes pressure drop) while providing excellent thermal shock resistance. [0009] A first aspect of this invention is a ceramic honeycomb filter comprising a porous ceramic honeycomb body having an inlet end and outlet end connected by adjacent inlet and outlet channels that extend from the inlet end to the outlet end of the ceramic body, the inlet and outlet channels being defined by a plurality of interlaced thin gas filtering porous partition walls between the inlet and outlet channels and by ceramic plugs, such that the inlet channel has an inlet ceramic plug at the outlet end of the ceramic body and the outlet channel has an outlet ceramic plug at the inlet end of the ceramic body such that a fluid when entering the inlet end must pass through partition walls to exit the outlet end, wherein the ceramic honeycomb body comprises a heat absorbing material that undergoes a reversible phase change that absorbs heat energy. In a particular embodiment, the heat absorbing material is selected such that the phase change absorbs energy at a temperature that minimizes the temperature rise due to combustion of Diesel soot in the ceramic honeycomb filter. [0010] Another aspect of the invention is a method of filtering Diesel soot comprising, [0011] i) providing a ceramic honeycomb filter having heat absorbing material that undergoes a phase change that absorbs heat energy, [0012] ii) passing, Diesel exhaust through the said ceramic honeycomb filter such that soot in said exhaust is captured by said filter, and [0013] iii) heating the ceramic honeycomb filter sufficiently such that the Diesel soot combusts wherein the heat absorbing material undergoes a phase change absorbing a portion of the heat generated from combustion of said soot. [0014] The filter may be used in any applications in which particulates such as soot need to be removed from a gaseous or liquid stream such as an automobile, train, truck or stationary power plant exhaust. The filter is particularly useful to remove soot from Diesel engine exhausts. In addition, the phase change materials may be incorporated into ceramic honeycomb supports for heterogeneous catalysis reactions (e.g., partial oxidation reactions) in which, for example, only the channels with the phase change material would be plugged and the other channels remaining open for the reactants and products to pass through the channels. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a graph of the temperature rise during the burn off of soot deposited on a filter having a phase change material of this invention. [0016] FIG. 2 is a graph of the temperature rise during burn off of soot deposited on a filter without the phase change material. DETAILED DESCRIPTION OF THE INVENTION [0017] Heat absorbing material that undergoes a phase change means a material that undergoes a phase change above room temperature and within the operating temperature of the filter (i.e., temperature below where the filter melts or decomposes) that reversibly absorbs heat such as melting from a solid to a liquid, changing crystalline structure or in the case of amorphous materials goes through a glass transition temperature or melting range. Generally, the phase change occurs at a temperature, for example, close to the temperature or temperature range where soot that is trapped in the filter combusts. The temperature is desirably above the temperature where the soot starts to combust. The temperature where the soot starts to combust may depend, for example, on the type of soot, application, or presence of catalysts in the filter. [0018] Generally, the temperature where the phase change occurs is at least about 400° C. to about 1200° C. Suitable ranges of course may be narrower, for example, the temperature may be at least about, 425° C., 450° C., 500° C., 525° C., 550° C., 575° C., 600° C., or 625° C. to at most about 1100° C., 1000° C., 900° C., 850° C., 800° C., 775° C., 750° C., 725° C. or 700° C. It is understood that the phase change may occur over at temperature range, but for the purposes herein, the temperature of the phase change is at the peak of the endotherm upon heating using well known standard thermal analysis techniques such as differential thermal analysis (DTA) or differential scanning calorimetry (DSC). [0019] In one embodiment, the heat absorbing material is a metal that has a shell comprised of a metal having a higher melting temperature, or ceramic with a higher melting temperature such as an oxide of the heat absorbing material when it is a metal. In such an embodiment, it is preferred that when the metal undergoes a phase change, the metal is contained within the shell and does not flow within the filter. Likewise, a shell may be used to contain, for example, an inorganic glass that may go through both a glass transition and melting range. In the case of an inorganic glass, the ceramic shell may be any suitable to contain the glass or in some instances may be a metal with a higher melting temperature. Generally, the shell has melting temperature that is substantially greater than the heat absorbing materials phase change temperature (e.g., melting temperature). The shell, for example, typically has a melting temperature that is at least about 200° C. to greater than or equal to the melting or decomposition temperature of the ceramic honeycomb filter itself. [0020] The shell, when employed, may be formed by any suitable method. For example, the shell may simply be container in which the heat absorbing material is placed and the container subsequently sealed. Subsequently sealing may be accomplished, for example, in the case of a metal, by brazing or welding a top onto the container. In the case of ceramic container, the container may be sealed by placing a top on heating sufficiently to create a ceramic or metallic bond. The metallic bond may be further reacted to form a ceramic bond where the reaction could be with a surrounding gas of the ceramic of the shell. [0021] In another embodiment, the ceramic shell may be formed by reacting the heat absorbing material, when, for example, it is a metal with a gas or other reactant (e.g., carbon) to form a metal-ceramic layer on the metal heat absorbing material. Generally, the temperature to form such a layer, which for convenience typically is an oxide, is great enough to easily react the surface of the metal, but not so great that the metal melts and flows prior to forming a sufficient ceramic layer necessary to impede the flow of the metal. Generally, this temperature is below the melting temperature of the metal to about 50% of the melting temperature in degrees Kelvin. For the sake of speed but with suitable control, the temperature may be 60%, 70%, 80% or 90% of the melting temperature of the metal. Suitable ceramics include, for example, nitrides, oxides, carbides, borides or combinations thereof (e.g., oxy-nitrides). As described above, an oxide or oxy-combination as described above for both stability and convenience (i.e., air may be used to form the oxide layer), are preferred. Most preferably the shell ceramic is an oxide. [0022] Examples of suitable metals include, aluminum, iron, tin, zinc, copper, nickel, alloys of each of the aforementioned or mixtures thereof. When the filter is used to capture Diesel soot, aluminum, aluminum alloy or mixtures thereof may be useful and in particular with an oxide layer that is able to contain the metal upon melting. Said oxide layer may be any suitable thickness to contain the metal, but typically is at least about 5 nm (nanometers) thick on average, but not so thick that the amount of metal that undergoes a phase change is substantially decreased (i.e., less than about 50% by volume of the total volume of the metal and oxide shell). Typically, the oxide layer is at least about 20 nm, 50 nm, 100 nm, 500 nm, 1 micrometer or even 10 micrometers to at most about 0.5 mm, 0.2 mm, 150 micrometers, 75 micrometers or even 25 micrometers on average. [0023] Examples of suitable glasses, include soda-lime-silicate glasses boro-silicate glasses such as PYREX, silica glasses such as VYCOR. Other glasses may include, for example, glasses described in Electrocomponent Sci. and Tech., 1975, Vol. 2, pp. 163-199 by R. G. Frieser, Tables IX, XIV and XVI. [0024] Examples of suitable salts include, NaCl, KCl, Na 2 B 4 O 7 , NaBr, NaBO 2 , K 2 MO 4 , KI, NaI, LiI, LiCl and mixtures thereof. [0025] The heat absorbing material (HAM) may be in any shape or size suitable to be placed within the honeycomb of this invention. For example, the HAM may be in the form of a rod, tube, pellet, ball, sheet, particulate or any other conceivable volumetric shape. [0026] In one embodiment, the HAM is in the form of particulates or rods that are placed in one or more channels of the filter where the channel is plugged at both ends to ensure the HAM remains within the filter. [0027] In another embodiment the HAM is a coating that may be applied to one or more porous ceramic partition walls or portion of one or more of said walls within the porosity of said wall or walls. [0028] In another embodiment, the HAM may comprise a portion or the entire plug for one or more channels. Such HAM plugs may be of varying lengths and may be different than the standard plugs. Where the HAM is only a portion of the plug, the plug material making up remaining portion of the plug may be any suitable material as described below. [0029] The porous ceramic honeycomb of the filter as well as the plugs (note, the plugs may be the same or a different ceramic than the honeycomb as well as may simply be the partition walls of the honeycomb pinched together to close off a channel) may be any suitable ceramic or combinations of ceramics such as those known in the art for filtering Diesel soot. Exemplary ceramics include alumina, zirconia, silicon carbide, silicon nitride, aluminum nitride, silicon oxynitride, silicon carbonitride, mullite, cordierite, beta spodumene, aluminum titanate, strontium aluminum silicates, lithium aluminum silicates. Preferred porous ceramic bodies include silicon carbide, cordierite and mullite or combination thereof. The silicon carbide is preferably one described in U.S. Pat. Nos. 6,582,796 and 6,669,751B1 and WO Publications EP1142619A1, WO 2002/070106A1. Other suitable porous bodies are described by WO 2004/011386A1, WO 2004/011124A1, US 2004/0020359A1 and WO 2003/051488A1. [0030] The ceramic is preferably a ceramic having acicular grains. Examples of such acicular ceramic porous bodies include those described by WO 2005/097706 and acicular mullite as described, for example, by U.S. Pat. Nos. 5,194,154; 5,173,349; 5,198,007; 5,098,455; 5,340,516; 6,596,665 and 6,306,335; U.S. Patent Application Publication 2001/0038810; and International PCT Publication WO 03/082773. [0031] The porous ceramic honeycomb, generally, has a porosity of about 30% to 85%. Preferably, the porous ceramic honeycomb has a porosity of at least about 40%, more preferably at least about 45%, even more preferably at least about 50%, and most preferably at least about 55% to preferably at most about 80%, more preferably at most about 75%, and most preferably at most about 70%. [0032] The honeycomb as well as the channels may be any geometric cross-sectional configuration such as round, oval, square, rectangle or any other geometric shape depending on the application. The honeycomb may be any size and is dependent upon the application. [0033] The partition walls may contain within the walls or coated upon the surface of the wall a catalyst. Such catalyst may be any useful to catalyze the combustion of soot, carbon monoxide and/or hydrocarbons. The catalyst preferably also abates one or more other pollutant gases in a Diesel exhaust stream such as NOx (e.g., selective catalyst reduction “SCR” to nitrogen and CO oxidized to form CO 2 ). [0034] It typically is desirable for the catalyst to be comprised of an oxide washcoat and a metal catalyst on the washcoat. A preferred washcoat is an oxide of aluminum, cerium, zirconium, aluminosilicate (e.g., zeolite) or combination thereof. More preferably the washcoat is an oxide of cerium, zirconium or combination thereof. Other exemplary washcoats that may be useful are those that are described in U.S. Pat. Appl. 2005/0113249 and U.S. Pat. Nos. 4,316,822; 5,993,762; 5,491,120 and 6,255,249. [0035] When using a washcoat, typical washcoats that are formed using ballmilling oxide particles may be used, but are not preferred because they tend to clog the pores of the partition walls of the honeycomb due to the average particle size typically being greater than 1 micrometer to about 20 micrometers. Examples of such washcoats are described by U.S. Pat. Nos. 3,565,830; 4,727,052 and 4,902,664. Preferably, the washcoat, when used, is precipitated from a solution as described by U.S. Pat. Appl. 2005/0113249, paragraphs 19-24, incorporated herein by reference. [0036] The washcoat particulates, preferably, are colloidal particles dispersed within a liquid. Colloid herein means a particulate having an average particle size of less than 1 micrometer by number. The colloid may be crystalline or amorphous. Preferably, the colloid is amorphous. The colloid is preferably an alumina, ceria, zirconia or combination thereof. Such colloids are available under the trade name NYACOL, Nyacol Nano Technologies Inc., Ashland, Mass. [0037] The colloid preferably has a small particle size where all of the particles are less than 750 nanometers (nm) in equivalent spherical diameter by number. Preferably the average particle size is less than about 500 nanometers (nm), more preferably less than about 250 nm, even more preferably less than about 100 nm, and most preferably less than about 50 nm to preferably at least about 1 nm, more preferably at least about 5 nm, and most preferably at least about 10 nm in diameter by number. [0038] The amount of catalyst in the partition wall may be any useful amount and may vary in or on a wall along the length of a channel or channels or from channel to channel. Generally, the amount of catalyst may vary from about 10 to about 6000 grams per cu-ft and is dependent, for example, on the application and particular honeycomb used. The volume, as is convention, is taken as the geometric volume of the honeycomb, which in this case is taken as the cross-sectional area of the honeycomb by the length of the honeycomb. [0039] Other examples of catalysts useful for combusting soot and hydrocarbons are described in col. 4, lines 25-59 of U.S. Pat. No. 4,828,807, incorporated herein by reference. Any of the catalysts described may be combined with a noble metal to improve the conversion of the gaseous pollutants traversing through the partition wall of the honeycomb filter. [0040] The noble metal (e.g., platinum, rhodium, palladium, rhenium, ruthenium, gold, silver or alloys thereof), when used in the partition wall of the honeycomb, is preferably comprised of Pt, Pd, Rh, or combination thereof. Preferably, the noble metal is comprised of Pt and more preferably, the noble metal is Pt. The amount of noble metal may vary over a large range depending, for example, on the application. Generally, the amount of noble metal is about 1 g/cu-ft to about 500 g/cu-ft. Preferably the amount of noble metal is at least about 1 , more preferably at least about 5 and most preferably at least about 10, to preferably at most about 250, more preferably at most about 125, and most preferably at most about 50 g/cu-ft. [0041] Other exemplary catalysts include directly bound-metal catalysts, such as noble metals, alkaline metal, alkali metal base metals and combinations thereof. Examples of noble metal catalysts include platinum, rhodium, palladium, ruthenium, rhenium, gold, silver and alloys thereof. Examples of base, alkali, alkaline metal catalysts include copper, chromium, iron, cobalt, nickel, zinc, manganese, vanadium, titanium, scandium, sodium, lithium, calcium, potassium, cesium and combinations thereof. The metal catalyst, preferably, is in the form of a metal, but may be present as an inorganic compound or glass, such as a silicate, oxide, nitride and carbide, or as a defect structure within the ceramic grains of the porous partition walls of the honeycomb. The metal may be applied by any suitable technique, such as those known in the art. For example, the metal catalyst may be applied by chemical vapor deposition. [0042] A second exemplary catalyst is one that is incorporated into the lattice structure of the ceramic grains of the porous ceramic. For example, an element may be Ce, Zr, La, Mg, Ca, a metal element described in the previous paragraph or combinations thereof. These elements may be incorporated in any suitable manner, such as those known in the art. [0043] A third exemplary catalyst is a perovskite-type catalyst comprising a metal oxide composition, such as those described by Golden in U.S. Pat. No. 5,939,354. Other exemplary catalysts include those describe at col. 4, lines 20-59 in U.S. Pat. No. 4,828,807, incorporated herein by reference. [0044] Other Exemplary methods for depositing one or more of the catalyst components are described in U.S. Pat. Nos. 4,515,758; 4,740,360; 5,013,705; 5,063,192; 5,130,109; 5,254,519; 5,993,762 and; U.S. Patent Application Publications 2002/0044897; 2002/0197191 and 2003/0124037; International Patent Publication WO97/00119; WO 99/12642; WO 00/62923; WO 01/02083 and WO 03/011437; and Great Britain Patent No. 1,119,180. [0045] After contacting the porous ceramic, for example, with the colloid, the porous body is typically dried by any suitable method such as letting the liquid medium dry at ambient temperatures or lightly heating (e.g., up to 400° C. or so) in any suitable gas such as dry air, nitrogen or any other gas useful to dry the solution or slurry. After, drying, typically the catalyst is further heated, for example, to adhere and/or realize the catalyst chemistry desired (e.g., decompose a carbonate to an oxide) to form the catalyst within the walls. Generally, the heating temperature is at least about 400° C. to about 1600° C. Typically, the temperature is at least about 500° C. to about 1000° C. The heating may be any suitable atmosphere such as those known in the art for any given catalyst. [0046] Differing zones of catalyst may be created by any suitable method, such as those known in the art such as dipping only one end of the honeycomb into a slurry or solution of the catalyst to be deposited. Combinations of dipping in a differing catalyst solutions or slurries at one or both ends, or immersion of the entire honeycomb in a catalyst solution or slurry followed by dipping another catalyst solution/slurry at one or both ends or any number of combinations thereof may be used to create the catalyzed filter. Removable coatings that act as barriers to the catalyst coatings may also be employed such as waxes. [0047] In performing the method of this invention, the filter of this invention may be placed in an exhaust system using a metal can that directs the exhaust through the filter as is conventional in the art and described. The Diesel engine is then run such that the exhaust passes through the filter, where the filter captures at least a portion of the soot emitted. Generally, the percentage by volume of soot that is captured in the filter is at least about 90% of that emitted. [0048] Upon combustion of the soot, the filter heats up even further, and the heat absorbing material undergoes a phase change that reduces the peak temperature achieved in the filter during combustion versus a like filter without the heat absorbing material or one that merely has a greater thermal mass (heat absorption merely from heat capacitance). The peak temperature generally is decreased by at least 2%, but may be, in increasing percent, decreased by 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 30%, 35%, 40%, but, generally, is not decreased by more than about 75%. EXAMPLES Example [0049] A 10×10 cell×3″ (overall dimensions ¾″×¾″×3) long acicular mullite Diesel particulate filter was made in a similar manner as in U.S. Pat. Publ. 2006-0197265, but was modified by the placement of thirteen (13) Al wires (1 mm diameter) in every other outlet channel in every other row. The pattern of Al wires is such that each inlet channel has one wall adjacent to a channel containing an Al wire. The added aluminum weighed 1.9686 g. The Al containing channels were plugged with Resbond 919 (Cotronics Corp., Brooklyn, N.Y.) ceramic cement and hence were no longer outlet channels. The DPF was then loaded with 0.146 g from the incomplete combustion of Diesel soot (˜5.5 g/L). [0050] Each of the soot loaded samples was heated in flowing N 2 (15 standard cubic feet per hour “scfh”) to 620-630° C. When the temperature had stabilized the gas was switched from N 2 to air again at 15 scfh to initiate uncontrolled soot combustion. Temperatures at the outlet end and the center of the monolith were monitored. The maximum temperature and temperature profile is shown in FIG. 1 . Comparative Example [0051] An acicular mullite filter made in the same way and of the same size as in the Example was used, except that no aluminum wires were present and those channels occupied by the aluminum wires in the Example were outlet channels. The amount of soot and the burn off of the soot was also the same as in the Example. The maximum temperature and temperature profile is shown in FIG. 2 . [0052] From FIGS. 1 and 2 , it is clear the Example, had a significantly lower maximum temperature and the temperature profile is substantially broadened, which is desirable because it a much milder thermal event. In addition, the broadening of the temperature profile may be useful in burning further soot in a controlled way without the typical insertion of more fuel (i.e., the phase change material upon reversion will emit heat energy, which may be used to ignite further soot). [0053] The following Claims, even though they may not explicitly depend from one another, the invention contemplates any combination of one or more embodiments of any one claim combined with any one or more claims.

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BACKGROUND OF THE INVENTION The invention relates to a process and an apparatus for injecting a radioactive sample of a substance into the reaction chamber of a reaction vessel for conversion of said substance, using an injection medium. Faced with the looming worldwide shortage of crude oil, there has been an increasing trend in recent times to turn development towards the conversion of solid fossil fuels into high-energy liquid products. Most hard coals and brown coals or lignites for example are suitable for hydrogenating liquefaction. However, the pressures and temperatures required for carrying out the conversion operation are unusually high in comparison with other technical processes. Accordingly, high levels of requirement are made in regard to the structure of the reaction vessels and the mode of carrying such a process into effect. In connection with the way in which the process is carried out, it is important for example to establish the residence time of the coal to be converted in the reaction vessel, and thus the rate of throughput. A suitable way of doing that is measuring by means of radioactive substances which are introduced into the reaction vessel in order to ascertain the residence time thereof by means of counter tubes. However, when dealing with high-pressure and high-temperature reaction vessels, difficulties are encountered in regard to introducing radioactive trace substances of that kind into the reaction vessel and the reaction procedure which takes place therein and which, in the case of a hydrogenating liquefaction operation, is carried out under pressures of the order of magnitude of from 300 to 500 bars and at temperatures of the order of magnitude of from 700° to 800° C. The idea of injecting substances into apparatuses or plants which are not under an increased pressure, by means of injection devices, for example simple injection nozzles, has long been known. In that procedure, the substances to be injected are disposed in a closed container comprising for example glass, which is inserted into and enclosed in the injection device and which is then crushed to liberate the substance to be injected, within the injection device. However, in that operation, difficulties may occur as glass splinters which are produced as a result of crushing the glass container can pass into the injection passage and can cause stoppages therein. Difficulties of that nature mean that it is not always possible to obtain precise measurement values. It will be appreciated that the known methods are out of the question from the outset, when the reaction vessels involve high pressures and high temperatures, as, when discharging the substances forming the result of the conversion operation from the reaction zone, and with the relief of pressure which occurs when that operation is performed, the energy conversion phenomena that occur, for example pressure is converted into flow energy or kinetic energy, are such that the valves and other equipment at the corresponding locations involved in that operation tend to be damaged or ruined by foreign bodies which may possibly be contained in the conversion substance. In any case, because of the operating conditions involved, the discharge members on the reaction vessels have a comparatively short operating life, even though they are made from high-grade materials, and renewing them is expensive. It would be prohibitive for the service life that can be achieved to be reduced due to influences as indicated above. SUMMARY OF THE INVENTION An object of the present invention is to provide a process for injecting a radioactive sample of a substance into the highly pressurized interior of a reaction vessel in which a substance is undergoing conversion. Another object of the invention is to provide a process for injecting a radioactive sample of a substance into the pressurized interior of a reaction vessel wherein the substance is undergoing conversion, which does not involve major difficulty in regard to handling the radioactively irradiated sample. Still another object of the present invention is to provide a process for injecting a radioactive sample of a substance into a pressurised reaction vessel, which permits a precisely controlled quantity of the sample to be readily injected. Yet another object of the present invention is to provide such a process which enables the sample which is to be injected, to be radioactively irradiated without serious difficulty. A further object of the present invention is to provide an apparatus for injecting a radioactive sample of a substance into a reaction chamber, which permits a precisely controlled quantity of the substance to be disposed in a readily handleable container within which it can be radioactively irradiated without difficulty and subsequently injected. A still further object of the present invention is to provide such an apparatus which is durable and reliable in operation. These and other objects are achieved by means of a process for injecting a radioactive sample of a substance into the reaction chamber of a reaction vessel for conversion of said substance using an injection medium. The sample is irradiated within a first container and, together therewith, is enclosed in a second container which can be separated from the pressurized interior of the reaction chamber, as by means of a valve. The second container with the irradiated sample therein is then optionally heated, and the sample is conveyed out of the first and second containers into the reaction chamber, by opening of the valve, by means of an injection medium which is under a pressure higher than the internal pressure in the reaction chamber. Apparatus for carrying out the process in accordance with the principles of the invention comprises a first container for receiving the sample to be irradiated therein, and a second pressure-resistant container which may be adapted to be heated when the first container with the sample therein, has been disposed in the second container. The second container can then be connected to the reaction vessel into which it is to be injected, by way of a suitable closure or shutoff means. The second container further has an intake opening for the injection medium to be introduced thereinto, thereby to discharge the irradiated sample from the second container into the reaction chamber. It will be seen therefore that a radioactive sample of a substance can be introduced into the interior of a reaction vessel in which that or another substance is undergoing conversion under high pressure and at elevated temperature. The process and the apparatus are simple and straightforward in regard to the manner of performance of the process and the apparatus configuration. As will be more clearly apparent hereinafter, an advantage of the mode of operation in accordance with the invention lies in good and easy handleability of the radioactively irradiated probe or sample, being first enclosed in a precisely controlled quantity in a manageable first container within which it can be radioactively irradiated. Then, the first container with the sample therein, now being radioactive, is put into a second container which is of a pressure-resistant and generally correspondingly thick-walled construction. The second container can then be connected to the high-pressure reaction vessel by way of a shut-off or closure member such as a valve, which is opened for the purpose of introducing the radioactive substance but which is otherwise closed. Desirably, the radioactive sample employed is a substance which is the same as or of the same nature as that which is being converted within the reaction vessel. For example, when dealing with the hydrogenating liquefaction of coal, such a sample may comprise the same or similar finely ground coal or such a coal suspended in oil. The use of a sample which is adapted to the substance in the reaction vessel, in that way, ensures that conversion of the substance in the interior of the reaction vessel is not adversely affected, as the sample itself also takes part in the conversion operation. In addition, in that way, the conversion products are not affected by the sample. A preferred mode of carrying the process into effect provides that the sample is enclosed within a first container which is of substantially cylindrical form and which has open ends. It may therefore be a tube portion, and the discharge opening thereof is advantageously slightly constricted. That means that the discharge flow speed of the sample is slightly increased so that it can be introduced into the reaction vessel without loss, through the injection opening and the valve when the latter is in an open condition. The intake opening and the discharge opening of the first container can be closed off with plugs or stoppers of a suitable material such as wax in order to retain the sample within the first container. A closure arrangement of that kind is adequate to permit the sample to be safely and securely handled during the radioactive irradiation operation. When converting coal for example, when wax is is used for the stoppers or plugs, it does not cause contamination of the substances which are being converted within the reaction vessel. Another advantageous possibility provides using a sample in the form of a coal-oil suspension which is introduced into the first container and which is then frozen therein by subzero cooling. When in a frozen condition, such a sample can be easily handled and subjected to radioactive radiation, in order then to be introduced into the reaction vessel. For the purposes of releasing the sample which is enclosed in or frozen in the first container, the second container can be heated, which causes the plugs or stoppers, or the sample itself, to melt after the first container has been introduced into the second container. By virtue of the second container being heated, the temperature and thus the viscosity of the sample can be accurately adjusted to the conditions of the conversion operation, which obtain in the reaction vessel, whereby it is possible to ensure that the reaction procedure within the reaction vessel is not detrimentally affected. For the purposes of better handling of the sample during the radioactive irradiation step and also for complying with the safety provisions which are required in that respect, it has been found advantageous for the first container to be put into intermediate storage in a storage container from which it is removed after the irradiation operation and then introduced into the second container. The sample or the first container is usually handled with tools which are suited to that purpose, so that it is possible to avoid the activated components being directly touched by hand. After the first container with the activated and possibly deep-frozen sample has been removed from the above-mentioned storage container and introduced into the second container, the first container is fixed within the second container, preferably by means of a clamping ring, and is sealed with respect to the second container in such a way that it is not subjected to the effect of a pressure from the exterior. There is therefore no possibility of the first container suffering deformation and being rendered useless, with the troublesome consequences that that would evolve, when the second container is subjected to a pressure. After the first container has been inserted and secured, the second container is closed with a high-pressure screw means which may preferably have a conical or tapered sealing edge which comes to bear against a co-operating surface of the second container in such a way that here too the necessary seal is formed. A construction of that kind has been found to be substantially more advantageous and reliable and also durable, than conventional sealing arrangements using ring seals or the like. In accordance with a further preferred feature of the invention, the sample which is enclosed in the second container may be subjected to a preliminary pressure by way of the connection for the injection medium or agent, making use of the latter for that purpose. The injection agent is for example a fluid which corresonds to the fluid by means of which the substance in the reaction vessel is being converted, being therefore for example oil when converting coal. Between the sample to be injected and the high-pressure closure of the second container is a small internal space or cavity in which the preliminary pressure of the injection agent takes effect. That preliminary pressure is for example from 20 to 50 bars and causes the sample substantially to remain in its position within the first container, or at least not to change its position in the opposite direction to the direction of injection, when the plugs or stoppers are removed or when the frozen sample is made fluid, and before it is injected into the reaction vessel. The operations of fixing the first container within the second container, heating the sample and applying the preliminary pressure by way of the injection agent ensure that in each case the sample to be injected is in a condition in regard to pressure, temperature and viscosity in which it is best suited for the injection process and is adapted in the best possible manner to the conditions in the reaction vessel. Those conditions can be experimentally ascertained and established in detail beforehand. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in longitudinal section through an apparatus for injecting a radioactive substance, with first container, FIG. 2 is a view in longitudinal section through the first container which contains the sample and which is disposed in a storage container, and FIG. 3 is a diagrammatic view of the injection apparatus, in relation to a reaction vessel. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, it will be seen therefrom that in the operative condition of the apparatus, disposed in the upper or front portion 3 of a housing 2, representing a second container, of the injection apparatus, which can be heated as by an electrical heating means 33 is a sleeve member or tube 1 which represents a first container. The tube 1 is provided with a closable opening 4 and 5 at each end. The tube 1 is introduced into the housing 2 of the injection apparatus through a charging opening 6. In the illustrated position the tube 1 is carried in the upper or front portion 3 of the housing 2, or more precisely, the space 7 within same, with such an accurate fit therein that there cannot be any flow around the outside wall surface of the tube 1. The tube 1 is fixed in the space 7 by means of a clamping ring 9 which can be screwed in through the charging opening 6 while the latter is open. A space 8 inside the housing 2, below or rearwardly of the ring 9, is also accessible through the opening 6 which can be closed by means of a high-pressure closure arrangement 10. The discharge opening 4 of the tube 1 is aligned with an injection opening 11 for the discharge of sample and injection agent. From the discharge opening 4, a feed conduit leads by way of a highpressure screw connection 12 to the interior of the reaction vessel (not shown in FIG. 1 but shown at 25 in FIG. 3) which in operation is under a high pressure and at a high temperature. Provided in a lower or rearward portion 13 of the housing 2, in the side wall thereof, is a flow opening or port 14 for the intake of the injection agent, the port 14 also being provided with a high pressure screw connection as indicated at 15 for connecting a feed conduit thereto. The port 14 communicates with the space 8 inside the housing 2, upstream of the tube 1 or the intake opening 5 thereof, as considered in the direction of flow of the injection agent as indicated at 16. Referring also at this point to FIG. 3, disposed between the high-pressure screw connection 12 and the reaction vessel 25 are a high-pressure valve 35 and, possibly, in conjunction therewith, a check valve 36 which is temporarily opened for carrying out the injection operation. The injection apparatus can be fixedly connected to a container for the injection agent, for example oil when injecting coal, by way of the screw connection 15. The injection agent is essentially a conveyor agent or flow medium for the sample to be injected. The connection 15 also has a further valve (not shown) with which the container for the injection agent can be switched on and off as required. Referring to FIG. 2, shown therein on a larger scale is the sleeve member or tube 1 which is used for carrying out the radioactive irradiation operation and possibly freezing the sample, in a storage container 17. The tube 1 comprises a cylindrical metal tube which is slightly tapered inwardly at its upper end which has the discharge opening 4 to provide a constriction in the flow therethrough. The second or intake opening through which the injection agent passes into the tube 1 at the other end thereof is indicated at 5. Shown within the tube 1 is a sample 18 to be injected. In a specific situation of use, the substance involved may be for example radioactively marked coal powder or a coal-oil suspension which is also marked. The openings 4 and 5 of the tube 1 are closed by closure plugs or stoppers 19 and 20 which can be easily melted and which comprise a suitable material for example wax. If the sample 18 is formed by a coaloil suspension, the plugs or stoppers 19, 20 may be omitted if the sample 18 has a sufficiently high solidification temperature. The storage container 17 in which the tube 1 is put into intermediate storage after the sample 18 has been radioactively irradiated also comprises a metal tube and can be closed at its one end by a screw-in plug or stopper 21 which has a shoulder portion 22 and a seal 23, which project into the opening 5 of the tube 1 and in so doing seal it off. Disposed at the other end of the container 17, within the container, is a further plug or stopper 24 which has a screw-threaded bore 34 for connection to an ejector member, for example a rod or bar. The screw-threaded bore 34 is a blind bore so that a sealing action is produced between the plug or stopper 24 and the tube 1, in the region of the edge 37. The plug or stopper 24 is mounted movably in the storage container 17 so that, after the plug or stopper 21 has been removed, the tube 1 can be easily pushed out of the container 17 for unloading same, through the opening 31 of the container 17. It will be seen that the container 17 has an inwardly extending flange at its end adjacent the stopper 24 to hold the latter in the container 17. The plug or stopper 24 can be braced with respect to the sleeve or tube 1, for sealing purposes. That can be effected in a simple manner by cooling, as is required in many situations in any case, as when using a coal-oil suspension as the sample. The severe cooling action results in shrinkage of the container 17 both in the peripheral direction and also in the longitudinal direction, the lengthwise shrinkage meaning that the plug or stopper 24 is pressed firmly against the end face of the sleeve member or tube 1, that has the discharge opening 4 therein. FIG. 3 shows the injection apparatus in conjunction with a reaction vessel for converting a substance in a high-pressure process. The substance to be converted flows through the reaction vessel 25 in the direction indicated by the arrow 26. Beside the reaction vessel 25, there are measuring devices 27, 28 and 29 and possibly further measuring devices which are arranged in a distributed array along the longitudinal axis of the reaction vessel 25 and by means of which, after a radioactive substance has been injected, the path of movement thereof, the residence time and so forth in the product flow in the reaction vessel can be followed. The kind and nature of substance to be injected generally depend on the nature of the phase in which the product flow to be investigated occurs. Depending on whether the product flow is in gaseous, liquid, possibly pasty or pulpy or solid form, the above-described apparatus can also be used for injecting gas, liquid or solid. An embodiment of the process provides the following mode of operation, using the injection apparatus shown in FIG. 1 and the storage container 17: 1. Charging the tube 1 for the purposes of irradiation of the substance: (a) Charging with coal powder: The steps of: casting the closure plug or stopper 19 of a fusible material in the upper slightly conical portion of the tube 1, with subsequent setting of the plug or stopper; introducing coal powder into the tube 1; closing the tube 1 at the other lower end by means of a wax plug or stopper 20, with subsequent setting thereof, in which connection the plug 20 can be prevented from falling out by means of a groove formed in the tube member, thus providing a form-locking or positive securing action; introducing the tube 1 into the container 17; and closing same by means of the screw plug 21. It will be appreciated that the tube 1 can also be charged when it is already in the container 17. (b) Charging with a coal-oil suspension: The steps of: dropping the suspension when of high viscosity into the tube 1 which has been introduced into the storage container 17; closing the tube 1 with the closure plug or stopper 21; when using a low-viscosity suspension, cooling the outer casing of the container to cause the suspension to solidify, while at the same time, due to the prestressing effect, producing a metallic sealing action at the opening 31, by the pressure applied by the plug or stopper 21 to the tube 1, between the two components. 2. Irradiation of the container 17 with the tube 1 therein, in a neutron field, to activate the sample 18 which is serving as a marking substance. 3. Introducing the tube 1 into the housing 2: (a) When using coal powder: When the wax closure members 19 and 20 are employed, there is no need for cooling (for example with dry ice); opening of the plug or stopper 21; pushing the tube 17 with its content out of the container 1 by means of the plug or stopper 24 using a suitable, tool (not shown) through the end opening 31 of the container 17; inserting the tube 1 with its discharge opening 4 leading into the housing 2 of the injection apparatus by means of a pair of pliers or the like with the high-pressure closure arrangement 10 in an open condition, through the opening 6 and into the upper or forward portion 7 of the space 8 within the apparatus; and fixing the tube 1 in the housing 2 by a clamping ring 9. (b) When using coal-oil suspension: The steps of: introducing the container 17 with tube 1 into a dismantling apparatus (not shown); cooling the content of the tube 1 by surface contact with a cooling jacket whereby the suspension representing the sample solidifies; dismantling the container 17; and introducing the tube. 4. Preparing for and carrying out the injection operation: The steps of: opening the feed line for the injection agent which is to be introduced through the port 14 and applying a preliminary pressure of the order of magnitude of 20 bars by means of the injection agent in the space 8 within the housing; heating the injection apparatus 2 by heating means 33; after the closure plugs or stoppers 19 and 20 have melted, increasing the pressure of the injection agent by way of the connecting line and the port 14 in the space 8 within the housing to a pressure which is higher than the pressure in the reactor 25; opening the connecting valve 35; and injecting the substance 18 by means of the injection agent which flows through the tube 1. When using a coal-oil suspension which has set within the tube 1, the heating means 33 causes that suspension to melt, instead of the closure plugs or stoppers 19 and 20. In other respects the manner of performing the injection operation corresponds to the manner of performance when using coal powder. When injecting a gas, the mode of operation may be the same as when injecting a powder. In that respect, the tube or sleeve member 1 may also be closed by means of diaphragms instead of the plugs or stoppers 19 and 20. After the tube has been introduced into the housing 2 of the injection apparatus and after closure thereof, the diaphragm can be ruptured by a shock pressure from the port 14 by means of an auxiliary agent, for example an inert oil, whereupon the gas is injected into the reaction vessel or some other piece of apparatus. It will be seen from the foregoing description that the process and the apparatus described are simple and straightforward, permitting easy handling of the materials involved. The apparatus is of such a nature as to provide for safe and easy handling of the radioactive substance in the environment of a hot reaction vessel which is under a high internal pressure, while also complying with the relevant regulations to be observed in relation to the use of radioactive materials. Various other modifications and alterations may be made in the above-described process and apparatus without thereby departing from the scope of the invention as defined by the appended claims.

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INCORPORATION BY REFERENCE This present disclosure claims the benefit of U.S. Provisional Application No. 61/591,726, “Control Algorithm for Smooth Turn On of the LED Lamp without a Phase Cut Dimmer” filed on Jan. 27, 2012, which is incorporated herein by reference in its entirety. BACKGROUND The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure. Light emitting diode (LED) lighting devices provide the advantages of low power consumption and long service life. Thus, LED lighting devices may be used as general lighting equipment in the near future to replace, for example, fluorescent lamps, bulbs, halogen lamps, and the like. SUMMARY Aspects of the disclosure provide a method. The method includes regulating a time for turning on a switch to transfer energy via a transformer in a first control mode, determining a turn-on time for a second control mode based on the regulated time in the first control mode, and controlling the switch based on the determined turn-on time in the second control mode to transfer energy via the transformer. In an embodiment, to regulate the time for turning on the switch to transfer energy via the transformer in the first control mode, the method includes regulating the time for turning on the switch to transfer energy with a substantially constant peak current. In an example, the method includes generating pulses with a pulse width modulated based on a sensed current. To determine the turn-on time for the second control mode based on the regulated time in the first control mode, in an example, the method includes searching a minimum turn-on time in the first control mode, and determining the turn-on time for the second control mode based on the minimum turn-on time. For example, the method includes counting based on a clock signal in response to pulses in a pulse width modulation (PWM) signal that controls the switch, and searching a minimum counted value in the first control mode. To determine the turn-on time for the second control mode based on the regulated time in the first control mode, the method includes determining the turn-on time for the second control mode based on the regulated time in the first control mode to transfer substantially the same amount of energy during an AC cycle in the first control mode and in the second control mode. Aspects of the disclosure provide a circuit that includes a controller. The controller is configured to regulate a time for turning on a switch to transfer energy via a transformer in a first control mode, determine a turn-on time for a second control mode based on the regulated time in the first control mode, and control the switch based on the determined turn-on time in the second control mode to transfer energy via the transformer. Aspects of the disclosure also provide an apparatus. The apparatus includes an energy transfer module and a controller. The energy transfer module is configured to transfer electric energy from a power supply to an output device. The controller is configured to regulate a time for turning on a switch in the energy transfer module to transfer energy in a first control mode, determine a turn-on time for a second control mode based on the regulated time in the first control mode, and control the switch based on the determined turn-on time in the second control mode to transfer energy. BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments of this disclosure that are proposed as examples will be described in detail with reference to the following figures, wherein like numerals reference like elements, and wherein: FIG. 1 shows a block diagram of an electronic system 100 according to an embodiment of the disclosure; FIG. 2 shows a plot 200 of voltage and current waveforms according to an embodiment of the disclosure; FIG. 3 shows a plot 300 of voltage and current waveforms according to an embodiment of the disclosure; FIG. 4 shows a flowchart outlining a process example according to an embodiment of the disclosure; FIGS. 5 and 6 show waveforms of an electronic system with voltage variation according to an embodiment of the disclosure. DETAILED DESCRIPTION OF EMBODIMENTS FIG. 1 shows a block diagram of an electronic system 100 according to an embodiment of the disclosure. The electronic system 100 operates based on an alternating current (AC) voltage V AC provided by an AC power supply 101 with or without a dimmer 102 . The AC voltage V AC can be 110V 50 Hz AC supply voltage, 220V 60 Hz AC supply voltage, and the like. According to an aspect of the disclosure, the electronic system 100 is operable with or without a dimmer 102 . When a dimmer 102 exists, the dimmer 102 includes a triode for alternating current (TRIAC) having an adjustable dimming angle α. The dimming angle α defines a size of a phase-cut range during which the TRIAC is turned off. During an AC cycle, when the phase of the AC voltage V AC is in the phase-cut range, the TRIAC is turned off. Thus, an output voltage of the dimmer 102 is about zero. When the phase of the AC voltage V AC is out of the phase-cut range, the TRIAC is turned on. Thus, the output voltage of the dimmer 102 is about the same as the AC voltage V AC . In an embodiment, the electronic system 100 is configured to detect whether the dimmer 102 exists, and to operate accordingly to achieve improved performance in either situations. For example, when the dimmer 102 exists, the electronic system 100 is configured to support the operations of the dimmer 102 , such as disclosed in Assignee's co-pending U.S. patent application Ser. No. 13/676,884, filed Nov. 14, 2012, which is incorporated herein by reference in its entirety. When the dimmer 102 does not exist, the electronic system 100 is configured to perform power factor correction (PFC) and total harmonic distortion (THD) reduction to improve energy efficiency, for example. According to an embodiment of the disclosure, the electronic system 100 has multiple operation modes, such as a first operation mode and a second operation mode, and operates in one of the multiple operation modes based on existence of the dimmer 102 . When the dimmer 102 exists, the electronic system 100 operates in the first operation mode to support the operations of the dimmer 102 . When the dimmer 102 does not exist, the electronic system 100 operates in the second operation mode to improve energy efficiency. During operation, in an example, at power-up, the electronic system 100 enters an initial operation mode. In the initial operation mode, the electronic system 100 detects whether the dimmer 102 exists, and accordingly determines the suitable operation mode to enter. In addition, the electronic system 100 can determine suitable values of operational parameters for the operation mode considering a smooth transition from the initial operation mode to the suitable operation mode and considering various variations in the system. Then, the electronic system 100 enters the suitable operation mode and configures the operational parameters using the determined values to enable a smooth turn-on of the electronic system 100 . It is noted that the initial operation mode can be one of the first operation mode and the second operation mode. In an example, at power-up, the electronic system 100 enters the first operation mode assuming that the dimmer 102 exists. It is noted that when the dimmer 102 does not exists, the electronic system 100 is operable in the first operation mode, but may have a relatively low power factor and a relatively large total harmonic distortions. When the electronic system 100 detects that the dimmer 102 does not exist, the electronic system 100 enters the second operation mode with suitable values for the operational parameters to enable a smooth transition from the first operation mode to the second operation mode, for example, without being noticeable to a user. In the FIG. 1 example, the electronic system 100 includes a rectifier 103 , a damping circuit 105 , a circuit 110 , an energy transfer module 120 , a current sensor 107 , and an output device 109 . These elements are coupled together as shown in FIG. 1 . The rectifier 103 rectifies an AC voltage to a fixed polarity, such as to be positive. In the FIG. 1 example, the rectifier 103 is a bridge rectifier. The bridge rectifier 103 receives the AC voltage, or the output voltage of the dimmer 102 , and rectifies the received voltage to a fixed polarity, such as to be positive. The damping circuit 104 is configured to filter out high frequency components and smooth the rectified voltage V RECT . The rectified voltage V RECT is provided to following circuits, such as the circuit 110 , the energy transfer module 120 , and the like, in the electronic system 100 . The energy transfer module 120 transfers electric energy provided by the rectified voltage V RECT to the output device 109 under the control of the circuit 110 . In the FIG. 1 example, the energy transfer module 120 includes a transformer T and a switch S T . The energy transfer module 120 also includes other suitable components, such as a diode D T , a capacitor C T , and the like. The transformer T includes a primary winding (P) coupled with the switch S T to receive the rectified voltage V RECT and a secondary winding (S) coupled to the output device 109 to drive the output device 109 . In an embodiment, the circuit 110 provides control signals to control the operations of the switch S T to transfer the electric energy from the primary winding to the secondary winding. In an example, the circuit 110 provides a pulse width modulation (PWM) signal with pulses having a relatively high frequency, such as in the order of 100 KHz, and the like, to control the switch S T . Specifically, in an example, when the switch S T is switched on, a current I P flows through the primary winding of the transformer T, and the switch S T . The polarity of the transformer T and the direction of the diode D T can be arranged such that there is no current in the secondary winding of the transformer T when the switch S T is switched on. Thus, the received electric energy is stored in the transformer T. When the switch S T is switched off, the current I P becomes zero. The polarity of the transformer T and the direction of the diode D T can enable the secondary winding to deliver the stored electric energy to the capacitor C T and the output device 109 . The capacitor C T can filter out the high frequency components and enable a relatively stable load current I LOAD to be driven to the output device 109 . The output device 109 can be any suitable device, such as a lighting device, a fan and the like. In an embodiment, the output device 109 includes a plurality of light emitting diodes (LEDs). The output device 109 and the other components of the electronic system 100 are assembled into a package to form an LED lighting device to replace, for example, a fluorescent lamp, a halogen lamp, and the like. The current sensor 107 is configured to sense the current I P flowing through the primary winding, and provide the sensed current to the circuit 110 . In an example, the current sensor 105 includes a resistor having a relatively small resistance such that a voltage drop on the resistor is small compared to the rectified voltage V RECT . The voltage drop is indicative of the current I P . In an example, the voltage drop is provided to the circuit 110 as the sensed current. It is noted that the electronic system 100 also includes other sensor circuits. For example, the electronic system 100 includes a triode for alternating current (TRIAC) sensor 105 , and a high voltage sensor 106 . The TRIAC sensor 105 is configured to provide a voltage signal to the circuit 110 to detect whether a TRIAC type dimmer exists. The high voltage sensor 106 is configured to provide a voltage signal to the circuit 110 to monitor the voltage level at the input of the energy transfer module 120 . According to an embodiment of the disclosure, the circuit 110 includes a detector 140 and a controller 130 . The detector 140 is configured to receive signals provided by sensors, such as the TRIAC sensor 105 , the high voltage sensor 106 , and the like, and detect various parameters from the signals, such as existence of a TRIAC type dimmer, and the like. The controller 130 is configured to adjust control signals, such as the PWM signal, and the like, based on the detected parameters to control the operations of the energy transfer module 120 . Specifically, in an example, the controller 130 has multiple control modes that generate the PWM signal according to different algorithms. In an example, the controller 130 has an initial control mode 150 that generates the PWM signal according to a first algorithm, and has a control mode 160 that generates the PWM signal according to a second algorithm. In this example, the first algorithm is used to generate the PWM signals to enable the operations of the dimmer 102 , and the second algorithm is used to generate the PWM signal to achieve improved power factor and total harmonic distortion when the dimmer 102 does not exist. In an embodiment, according to the first algorithm, the controller 130 provides the PWM signal to the switch S T to maintain a relatively constant peak current in the primary winding when the TRIAC in the dimmer 102 is turned on. In an example, when the controller 130 detects that the TRIAC in the dimmer 102 is turned on, the controller 130 provides the PWM signal to the switch S T to repetitively turn on and off the switch S T to maintain the relatively constant peak current. For example, at a time, the controller 130 changes the PWM signal from “0” to “1” to turn on the switch S T . When the switch S T is turned on, the current I P starts to increase. The current sensor 107 senses the current I P , for example, in a form of a voltage drop on a resistor, and provides sensed voltage drop to the controller 130 . The controller 130 receives the sensed voltage drop, and changes the PWM signal from “1” to “0” to turn off the switch S T when the sensed voltage drop is substantially equal to a threshold, such as 0.4V, and the like. In an example, the first algorithm is implemented as a state machine to detect the on/off state of the TRIAC based on the sensed current I P and then generates the PWM signal according to the detected state, such as disclosed in Assignee's co-pending U.S. patent application Ser. No. 13/676,884, filed Nov. 14, 2012, which is incorporated herein by reference in its entirety. Further, in the embodiment, according to the second algorithm, the controller 130 provides the PWM signal to control the switch S T to have a relatively constant turn-on time over the switching cycles in an AC cycle. For example, in an AC cycle, the PWM signal includes pulses to repetitively switch on and off the switch S T . The controller 130 can maintain the pulses in the PWM signal to have the same pulse width during the AC cycle, such that the turn-on time of the switch S T over the switching cycles in the AC cycle is about the same. It is noted that, according to an aspect of the disclosure, the turn-on time in different AC cycles can be different. In an example, the turn-on time and switching frequency are fixed during an AC cycle, but are adaptively changed over time. FIG. 2 shows a plot 200 of voltage and current waveforms for the electronic system 100 when the dimmer 102 does not exist and the controller 130 is in the control mode 160 and performs the second algorithm. The plot 200 includes a first waveform for the rectified voltage V RECT and a second waveform for the current I P . The first waveform shows that the rectified voltage V RECT has a rectified sinusoidal curve. The second waveform shows that the peak current of the switching cycles follows the shape of the first waveform due to the fixed turn-on time for the control mode 160 during an AC cycle. Thus, the average of the current I P has substantially the same phase as the rectified voltage V RECT , and the power factor correction can be achieved, and the energy efficiency can be improved. FIG. 3 shows a plot 300 of voltage and current waveforms for the electronic system 100 when the dimmer 102 exists, and the controller 130 is in the initial control mode 150 and performs the first algorithm. The plot 300 includes a first waveform for the rectified voltage V RECT and a second waveform for the current I P . The first waveform shows that the rectified voltage V RECT can be zero during a phase-cut range when the TRIAC in the dimmer 102 is turned off. The second waveform 320 shows that the peak current in the switching cycles is about the same in an AC cycle due to the constant peak current control of the initial control mode 150 . It is also noted that the controller 130 also controls the PWM signal based on other parameters. For example, according to the first algorithm, the controller 130 can control the PWM signal based on, for example, a maximum on time (i.e., 10 μs), a minimum frequency (i.e., 70 KHz), a maximum frequency (i.e., 200 KHz), and the like. Further, in an example, according to the second algorithm, the controller 130 limits a maximum peak current in the primary winding. For example, the current sensor 107 senses the current I P , and provides a sensed voltage drop indicative of the current I P , to the controller 130 . In a switching cycle, when the controller 130 changes the PWM signal from “0” to “1” to turn on the switch S T , the sensed voltage drop is monitored. When the sensed voltage drop is lower than a threshold, such as 0.6V, the controller 130 changes the PWM signal from “1” to “0” to turn off the switch S T in a manner to maintain the relatively constant turn-on time. When the sensed voltage is equal or above the threshold, the controller 130 changes the PWM signal from “1” to “0” to turn off the switch S T earlier than the constant turn-on time to avoid the current I P to further increase. In another example, according to the second algorithm, the controller 130 uses a quasi-resonant control method. According to the quasi-resonant control method, a frequency of the PWM signal is not fixed, and is synchronized with a resonance frequency governed by inductance and capacitance in the electronic system 100 . In this example, a voltage across the secondary winding of the transformer T is sensed and provided to the controller 130 . When the switch S T is turned off, the voltage across the secondary winding resonates. The controller 130 changes the PWM signal from “0” to “1” when the voltage across the secondary winding is at the valley. According to an aspect of the disclosure, due to the difference in the control algorithms, when the controller 130 switches from one control mode to another control mode, the transition can be noticeable and can affect user experience. For example, when the dimmer 102 does not exist, the controller 130 changes from the initial control mode 150 to the control mode 160 . When the two control modes control the energy transfer module 120 to deliver significantly different energy per AC cycle to the output device 109 , the LEDs in the output device 109 may flash at the time of control mode transition, and cause unpleasant user experience during the transition. In addition, various variations in the power supply and the electronic system 100 may also cause smooth transition to be challenging. For example, the AC voltage V AC may vary from 90V AC voltage to 135V AC voltage, the inductance in the electronic system 100 may have over 20% variation, and a frequency of a system clock used by the circuit 110 may have over 20% variation. According to an embodiment of the disclosure, during the initial control mode 150 , the controller 130 determines suitable values for operational parameters for the control mode 160 based on the values in the initial control mode 150 to enable the energy transfer module 120 to transfer about the same amount of energy per AC cycle during the transition from the initial control mode 150 to the control mode 160 . As a result, the LEDs emit about the same amount of light during the transition, and thus the transition is not noticeable. In an example, the controller 130 is configured to search for a minimum turn-on time during the initial control mode 150 , and then determines the initial turn-on time for the control mode 160 based on the minimum turn-on time. For example, the controller 130 includes a counter circuit (not shown) that counts in response to pulses in the PWM signal during the initial control mode 150 . The counter circuit can count based on a system clock used by the circuit 110 . In an example, the counter circuit starts counting from zero in response to a leading edge of a pulse, and stops counting in response to a trailing edge of the pulse. The counted value is indicative of the pulse width, and is indicative of the turn-on time of the switch S T . Because the turn-on time of the switch S T is a function of the inductance and the voltage level of the power supply, and the counter circuit counts based on the system clock, the variations in the inductance, voltage level of the power supply and the system clock have been taken account into the counted value. Based on the counted values in one or more AC cycles, the controller 130 searches a minimum counted value. Based on the minimum counted value, the controller 130 determines a counting value for the control mode 160 that can be used to control the turn-on time of the switch S T in a switch cycle. In an example, the counting value is determined to match the transferred energy per AC cycle for the initial control mode 150 and the control mode 160 . In an example, the counting value is about one and a half of the minimum counted value. Accordingly, the maximum peak current in the control mode 160 is one and a half of the peak current in the initial control mode 150 , and the maximum delivered energy in a switching cycle is about twice of the energy delivered in a switching cycle of the initial control mode 150 . During the initial one or more AC cycles of the control mode 160 , the controller 130 can use the same switching frequency as the last switching frequency of the initial control mode 150 . Further, because the minimum energy delivered in a switching cycle is zero in the control mode 160 , thus the average transferred energy per AC cycle is about the same for the initial control mode 150 , and the initial AC cycles of the control mode 160 . According to an aspect of the disclosure, in the control mode 160 , the controller 130 generates the PWM signal based on the determined counting value for one or more initial AC cycles to enable smooth transition. For example, when the controller 130 generates a leading edge of a pulse, the counter circuit starts counting from zero for example. When the counter circuit counts to the determined counting value, the controller 130 generates the trailing edge of the pulse. It is noted that the counting value can be adaptively changed after the initial AC cycles in the control mode 160 . It is noted that the electronic system 100 can be implemented using one or more integrated circuit (IC) chips. In an example, the circuit 110 is implemented as a single IC chip. Further, the switch S T can be implemented as a discrete device or can be integrated with the circuit 110 on the same IC chip. The controller 130 can be implemented as circuits or can be implemented as a processor executing instructions. FIG. 4 shows a flowchart outlining a process example 400 executed by the controller 130 according to an embodiment of the disclosure. The process starts at S 401 and proceeds to S 410 . At S 410 , the electronic system 100 is powered up, and the controller 130 enters the initial control mode 150 . In an example, in the initial control mode 150 , the controller 130 generates a PWM signal according to the first algorithm, which is based on using a constant peak current to drive the energy transfer module 110 to enable the operations of the dimmer 102 assuming the dimmer 102 exists. At S 420 , the controller 130 searches for a minimum turn-on time. In an example, the controller 130 includes a counter circuit to count in response to pulses in the PWM signal during the initial control mode 150 . The counter circuit can count based on the system clock used by the circuit 110 . In an example, in a switching cycle, the counter circuit starts counting in response to a leading edge of a pulse, and stops counting in response to a trailing edge of the pulse. The counted value is indicative of the pulse width, and is indicative of the turn-on time of the switch S T in the switching cycle. Then, the controller 130 searches for a minimum counted value in one or more AC cycles. The minimum counted value is indicative of the minimum turn-on time. At S 430 , the controller 130 determines whether the dimmer 102 exists. In an example, the controller 130 includes a state machine to implement control functions of the initial control mode 150 . The state machine detects the on or off state of the TRIAC in the dimmer 102 . When a TRIAC off state has been consistently detected, the controller 130 determines that the dimmer 102 exists; and when the TRIAC off state is not detected for one or more AC cycles, the controller 130 determines that the dimmer 102 does not exist. When the dimmer 102 exists, the process proceeds to S 460 that the controller 130 stays in the initial control mode 150 ; otherwise, the process proceeds to S 440 . At S 440 , the controller 130 determines a turn-on time for the control mode 160 based on the minimum turn-on time from the initial control mode 150 . In an example, the controller 130 determines a counting value indicative of the turn-on time based on the minimum counted value. For example, the counting value is about one and a half of the minimum counted value. At S 450 , the controller 130 enters the control mode 160 to generate the PWM signal based on the determined turn-on time for one or more initial AC cycles. In an example, during an initial AC cycle, when the controller 130 generates a leading edge of a pulse, the counter circuit starts counting from zero for example. When the counter circuit counts to the determined counting value, the controller 130 generates the trailing edge of the pulse. Because the counting value is one and a half of the minimum counted value, the maximum peak current in the control mode 160 is about one and a half of the peak current in the initial control mode 150 , and the maximum delivered energy in a switching cycle is about twice the delivered energy in a switching cycle of initial control mode 150 . In addition, the minimum delivery energy in the control mode 160 is about zero. When the switching frequency is about the same for the initial AC cycle in the control mode 160 and the initial control mode 150 , the average transferred energy per AC cycle is about the same for the initial control mode 150 , and the initial AC cycle of the control mode 160 . Thus, the LEDs emit about the same amount of light during the initial AC cycle of the control mode 160 and during the initial control mode 150 , and the transition from the initial control mode 150 to the control mode 160 can be smooth and not noticeable. Then the process proceeds to S 499 and terminates. FIG. 5 shows a plot 500 of simulation waveforms for the electronic system 100 with 120V AC input voltage. The plot 500 includes a first waveform 510 for the rectified voltage V RECT , a second waveform 520 for the current I P , a third waveform 530 for a signal (TRIAC OFF) in the electronic system 100 that is indicative of TRIAC on/off state, and a fourth waveform 540 for the load current I LOAD to the output device 109 . At power up, during the first three half AC cycles, the controller 130 is in the initial control mode 150 and the electronic system 100 is in the first operation mode to support the operations of the dimmer 102 assuming the dimmer 102 exists. In the initial control mode 150 , the controller 130 generates the PWM signal to turn on and off the switch S T to maintain a relatively constant peak current, as shown by 521 . Further, in the initial control mode 150 , the controller 130 searches for a minimum turn-on time. Based on the minimum turn-on time, the controller 130 determines a turn-on time for the control mode 160 . In the FIG. 5 example, the controller 130 detects the on/off state of the TRIAC based on the TRIAC OFF signal. When the TRIAC OFF signal indicates no TRIAC off state for half an AC cycle for example, the controller 130 determines that the dimmer 102 does not exist and switches to the control mode 160 . The electronic system 100 then operates in the second operation mode to improve energy efficiency. For example, the average current I P has about the same phase as the rectified voltage V RECT , as can be seen by 523 , and the energy efficiency can be improved. In the initial cycles of the control mode 160 , the controller 130 generates the PWM signal based on the determined turn-on time to enable a smooth transition from the initial control mode 150 to the control mode 160 . As can be see, the average load current I LOAD per AC cycle is about the same before and after the transition. FIG. 6 shows a plot 600 of simulation waveforms for the electronic system 100 with 230V AC input voltage. Similar to the waveforms in FIG. 5 , the average load current I LOAD per AC cycle is about the same before and after the transition. According to an embodiment of the disclosure, because the minimum turn-on time in the initial control mode 150 is a function of the input voltage, when the turn-on time for the control mode 150 is determined based on the minimum turn-on time, the voltage variation is taken into consideration in the turn-on time, and the smooth transition from the initial control mode 150 to the control mode 160 can be performed. While aspects of the present disclosure have been described in conjunction with the specific embodiments thereof that are proposed as examples, alternatives, modifications, and variations to the examples may be made. Accordingly, embodiments as set forth herein are intended to be illustrative and not limiting. There are changes that may be made without departing from the scope of the claims set forth below.

4y

BACKGROUND OF THE INVENTION The present invention relates to use of vitamin E to normalize blood coagulation during the oral intake of high unsaturated fatty acids of omega-3 type ("omega-3 fatty acids") i.e., fatty acids that have a double bond between carbons 3 and 4 such as eicosa-pentanoic acid ("EPA") and docosahexanoic acid "DHA"). In the context of the present invention, "high" unsaturated fatty acids are those that comprise 3 to 6 preferably 5 to 6 double bonds and 18 to 22 preferably 20 to 22 carbon atoms. In the 1960s and 1970s, the eating habits of Eskimos in Greenland were studied to determine if a relationship existed between the food they consumed and an observed, low rate of myocardial and brain infarctions. A relationship between consumption of fish oil and the low rate of infarctions was found to exist. Studies of fish oil revealed that its major constituent was high unsaturated fatty acids of omega-3 type, especially EPA and DHA. Further studies revealed that upon ingestion, EPA and DHA, instead of arachidonic acid ("AA"), also known as eicosatetranoic acid, became integrated into the platelet membranes, thereby reducing platelet aggregation and changing the rheological properties of the blood in a positive way, resulting in less infarction. Coincidental with the use of such fatty acids, formation of anti-inflammatory leukotrienes, and a reduction in blood sugar levels and in increases in blood pressure were observed. A significant finding relating to the risk of infarction is that, with continuous use of the abovementioned fatty acids in quantities of about 50-1000 mg/day, blood cholesterol levels were reduced as much as 35% and blood triglyceride levels were reduced as much as 58%. Reduction in blood cholesterol level refers, in particular, to reduction in low density lipoproteins ("LDL") and a corresponding increase in high density lipoproteins ("HDL"), which counteract infarction. A side effect of their fish diet is an increased tendency among the Eskimos to bleed, as reported by Saynor and Varell, Medical Science 8: 379 (1980). These authors were unable to find in the Eskimos, however, any sigificant change in partial thromboplastin time ("PTT") or in thrombin coagulation time. In contrast, Terano et al, Atherosclerosis, 46: 321-331 (1983), found a significant increase in prothrombin time ("PT"), from 11.5 to 12.6 seconds, but no significant changes in PTT, cholesterol phospholipid, HDL-cholesterol, malondialdehyde and vitamin E levels in the serum of these Eskimos. Based upon an examination of over one hundred patients given high unsaturated fatty acids such as EPA and/or DHA in quantities of up to 1000 mg/day, over a period of four or more weeks, it was found that the PT of these patients, measured as a "Quick value," dropped below that of an untreated patient, resulting in a reduction to 45% below normal. For purposes of this description, the phrase "Quick value" is used to denote normal prothrombin time, measured with diluted plasma of healthy persons (i.e., 12 seconds), divided by a test subject's prothrombin time. Prothrombin time is measured in accordance with conventional laboratory methods. In essence, citrated plasma is mixed with a surplus of thrombokinase and calcium chloride, and time required for coagulation is measured. An increase in prothrombin time, therefore, is equivalent to a decrease in Quick value. For patients undergoing treatment with anticoagulants such as indandiones and dicumaroles, use of high unsaturated fatty acids can intensify the effect of anticoagulants, and can lead to a fast drop in Quick value to beyond a therapeutically safe limit, necessitating discontinuation of anticoagulants. Omega-3 fatty acids are used not only under direct medical supervision in the treatment of acute illnesses but also prophylactically by the lay public, without medical supervision, as dietetic supplements. Accordingly, the above-described risk is considerable. Consequently, it would be desirable if there is some way in which blood coagulation, measured as PT, can be normalized despite a person's use or consumption of a high dose of high unsaturated fatty acids like EPA and DHA. SUMMARY OF THE INVENTION It is therefore an object of the present invention to counteract the effect of an increased tendency to bleed caused by consumption of high unsaturated fatty acids such as eicosapentanoic acid and docosahexanoic acid. It is another object of the present invention to counteract the aforementioned effect without adversely influencing the ability of such fatty acids to cause a reduction in blood cholesterol level. It is yet another object of the present invention to provide a means to normalize blood coagulation in persons who consume high unsaturated fatty acids. In accomplishing these and other objects, there has been provided, in accordance with one aspect of the present invention, a method for normalization of blood coagulation during intake of a high omega-3 fatty acid, comprising the step of combining oral administration of a predetermined amount of said fatty acid with oral administration of vitamin E, wherein said vitamin E is administered in an amount ranging from about 40 to 100% by weight of said amount of fatty acid. In accordance with another aspect of the present invention, an article of manufacture comprising vitamin E and at least one omega-3 fatty acid wherein said vitamin E is present in an amount ranging from about 40% to 100% by weight of said fatty acid. In one preferred embodiment, the article of manufacture comprises a kit, in which vitamin E and the omega-3 fatty acid are kept in separate containers. In another preferred embodiment, the article of manufacture comprises a mixture of omega-3 fatty acid and vitamin E. Further objects, features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific example, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS The present invention relates to the use of vitamin E for normalization of blood coagulation during intake of omega-3 fatty acid, such as EPA and DHA, wherein the amount of vitamin E used is 40 to 100% by weight of the fatty acids. The present invention also relates to an article of manufacture, either in the form of a kit or a mixture comprising omega-3 fatty acid and vitamin E, the latter of which is 40 to 100% by weight of the fatty acids. It has been discovered that vitamin E, also known as alpha-tocopherolacetate, when used in combination with omega-3 fatty acid, at a concentration of about 40 to 100% by weight relative to the weight of said fatty acid, effectively prevents an increase in prothrombin time or restores to normalcy, within a short time, an existing increase in prothrombin time. In accordance with the present invention, omega-3 fatty acids like EPA and DHA can be used as a fish oil preparation, as a concentrate, or in a purified form, all in the form of a liquid or a capsule. Such an omega-3 fatty acid can be administered as a drug or taken as a dietary supplement in a dose sufficient to cause an increase in prothrombin time, preferably, in an amount ranging from 50 to 1000 mg per dose. Pursuant to the present invention, vitamin E can be taken separately, e.g., in the form of a commercially available preparation like tocopherolacetate, or in admixture with an omega-3 fatty acid. The amount of vitamin E to be taken, within the context of the present invention, depends on the amount of omega-3 fatty acid to be used. Doses of vitamin E sufficient to cause normalization of prothrombin time can be taken, with the amount preferably ranging from about 40% to 100% by weight of the amount of fatty acid taken (or to be taken), and most preferably, in an amount ranging from about 30 to 1000 mg per dose. Doses of vitamin E higher than the abovedescribed range generally produce no additional effect and are preferably not used, thereby to avoid increasing the dosage and the risk of incurring undesirable side effects unnecessarily, and to avoid economic waste. Doses of vitamin E lower than the above-described range are typically ineffective, particularly in the range of 1% to 3% by weight of omega-3 fatty acid, for example, when used in the 1% to 2% range as an antioxidant in mixtures comprising fatty acid, which is relatively oxidation-sensitive. Appropriate doses of vitamin E can be taken in parallel with the fatty acids, or taken separately, e.g., after commencement of omega-3 fatty acid therapy. In accordance with the present invention, an article of manufacture can be prepared that comprises omega-3 fatty acid and vitamin E as separate components in a kit, or that comprises omega-3 fatty acid in admixture with vitamin E. The vitamin E suitable for use in the present invention includes preparations in soft or hard gelatin capsules, preparations in the form of tablets, or sugar-coated tablets, and preparations mixed into fish oil. Vitamin E and the omega-3 fatty acid preparations can optionally comprise other auxiliary substances of the sort usually present in commercial preparations of these compounds. One preferred embodiment of the present invention comprises a mixture of high unsaturated fatty acids such as EPA and/or DHA, in an amount of about 50 to 1000 mg and vitamin E, in an amount of about 40 to 1000 mg, in a single dose. This mixture can be given orally every day over a period of time to treat patients who are in a high risk group for myocardial or brain infarction, or who have a need to lower their blood cholesterol levels. Treatment comprising such a mixture can be given, for example, for a period of 4 to 6 weeks or until the desired level of blood cholesterol is achieved or maintained. The mechanism is unknown by which vitamin E maintains or restores normal blood coagulation when used at a high concentration in combination with high unsaturated fatty acids. Perhaps the spontaneous drop in Quick value upon fatty acid consumption is caused by a decrease in prothrombin formation resulting from bonding of vitamin K to the high unsaturated fatty acids. Additional intake of vitamin E would then restore the level of free vitamin K, thereby restoring prothrombin formation. This explanation can account for the observation that an amount of vitamin E as a percent of an amount of unsaturated fatty acids has to be used. In any event, the observed effect of vitamin E intake on coagulation time of patients who are ingesting omega-3 fatty acid is surprising in part because vitamin K, not vitamin E, is essential for blood coagulation. The correlation between vitamin E and coagulation time is especially unexpected since no change in serum vitamin E level has been observed during long-term usage of EPA and DHA. See Terano et al, loc. cit. The present invention is further described below by reference to the following illustrative example. EXAMPLE 1 Effect of vitamin E on prothrombin time of subjects given oral dosages of omega-3 fatty acids A total of one hundred and twelve (112) subjects were studied and their prothrombin times and serum vitamin E levels monitored, before and after oral administration of omega-3 fatty acid and vitamin E. Results are recorded in Table 1 below. Fatty acids were given in the form of a capsule as either purified EPA or purified DHA, at a dose of up to 1000 mg per subject per day for a period of either six weeks (see column III) or ten weeks (see column IV), respectively. Vitamin E was given separately in a dose of 500 mg per patient per day for a period of four weeks, commencing six weeks after initiation of (but continuing administration of) fatty acid therapy (see column IV). Prothrombin time of normal individual was determined to be approximately 12 seconds. Prothrombin time was measured, and the Quick value was calculated, for each subject, before and after treatment. The Quick values for all subjects were averaged before treatment (row 2, column II), after six weeks of treatment with omega-3 fatty acid alone (row 2, column III), and after combined treatment with omega-3 fatty acid and vitamin E (row 2, column IV). Serum vitamin E level of each subject was determined before commencement of the omega-3 fatty acid treatment, and was found to range from about 0.5 to 1.6 mg/100 ml. Each subject's pretreatment serum vitamin E level was deemed his personal "normal value" (row 3, column II). Serum vitamin E levels, as a percentage of each subject's pretreatment level, were determined and the levels for all subjects were averaged after six week of treatment with omega-3 fatty acid alone (row 3, column III) and after combined treatment with omega-3 fatty acid and vitamin E (row 3, column IV). TABLE 1__________________________________________________________________________EXPERIMENTAL RESULTSI II III IV__________________________________________________________________________Number of Subjects Before Omega-3- After 6 Weeks After 6 weeksn = 112 fatty acid of Omega-3-fatty of Omega-3- therapy acid therapy.sup.1 fatty acid therapy followed by 4 weeks of Omega-3 fatty acid and vitamin E therapy.sup.2Quick value.sup.3 96% 58% 95% n = 112 n = 112 n = 112Vitamin E personal 60% of 100% of(Tocopherol) "normal "normal value" "normal value".sup.4 = 100% n = 112 range" n = 112 n = 112__________________________________________________________________________ LEGEND: .sup.1 With up to 1000 mg of EPA or DHA per dose. .sup.2 With EPA or DHA as in column III, and 500 mg of vitamin E per dose .sup.3 Quick value = [normal prothrombin time] ÷ [prothrombin time of tested subject]. A prothrombin time of 12 seconds is used as normal prothrombin time. Results represent an average Quick value of all tested subjects expressed as a percentage of normal quick value. .sup.4 Normal serum vitamin E level of tested subjects ranges from about 0.5-1.6 mg/100 ml. Each subject's serum vitamin E level before treatment is his or her personal "normal value." Results represent an average of al tested subjects expressed as a percentage of his or her personal normal value. Before administration of omega-3 fatty acid, Quick value of the 112 subjects averaged 96% of normal. After 6 weeks of omega-3 type fatty acid therapy, Quick value of these subjects dropped to an average of 58% of normal. But after 6 weeks of omega-3 type fatty acid therapy alone and 4 weeks of combined omega-3 type fatty acid therapy and vitamin E therapy, the Quick value of these subjects returned to an average of 95% of normal. The vitamin E level was found to drop to 60% of normal when the omega-3 fatty acid was given without vitamin E, but returned to 100% of normal when fatty acid was given in combination with vitamin E. The results show, therefore, that administration of omega-3 fatty acid lowers the Quick value of treated subjects, while administration of vitamin E restores the Quick value of treated subjects to normalcy. These results are entirely unexpected since Saynor et al, loc. cit., did not find any significant change associated with prothrombin within a 5-week period during which each tested persons was given, on a daily basis, fish oil comprising a high EPA content. In addition, Terano, loc. cit., did not find any significant changes in serum vitamin E levels in people on fish diets.

4y

FIELD OF THE INVENTION The invention relates to a device with a magnetic position sensor comprising a field sensor and analysis electronics for linear displacements of a rod-shaped component, in particular the shaft of an actuator, with an element generating a magnetic field and a position sensor measuring the magnetic field strength angle of this field, the field angle signal determined by this sensor being used for displacement path determination. BACKGROUND OF THE INVENTION U.S. Pat. No. 5,570,015 discloses a magnetic position measurement device with which linear displacements of a rod-shaped component, for example a valve shaft, can be measured. A particular measurement unit, which consists of a shaft used for measurement purposes only and the position sensor, is placed on the rod-shaped component whose displacements are to be measured. Let into the shaft of the measurement unit is a rod-shaped magnet which generates a magnetic field in the longitudinal direction of the shaft. The position sensor is arranged fixedly in the area of the magnetic field. On relative displacements of the shaft in relation to its position, the position sensor measures by means of field sensors which, using analysis electronics, determine the magnetic field strength angle approximately proportionally to the displacement path. The path proportionality exists however only within a certain range. Apart from the large space required, the drawback of this arrangement is that the shaft must not turn. If shielding is used, the device no longer works sufficiently linearly and is therefore no longer sufficiently precise. SUMMARY OF THE INVENTION It is an object of the invention to provide a device with a magnetic position sensor which is simpler and smaller in structure, but in particular performs its measurements contactlessly and directly on the rod-shaped component of the actuator. According to the invention, this object is achieved in that the element generating a magnetic field is an axially magnetized magnet casing which surrounds the rod-shaped component of the actuator itself, is fixedly connected thereto and can rotate therewith about its displacement axis. If the element generating the magnetic field is attached directly to the shaft of the actuator, there is no need for a separate shaft of the measurement unit. Another advantage is that the shaft can rotate about its own axis without this affecting the measurement. This is very important because, in this case, a round actuator shaft does not require a twist-resistant guide for measurement. For faultless operation, it is advantageous if the actuator shaft consists of a non-ferromagnetic or only a weakly ferromagnetic material. The position sensor is also applicable in the case of inaccessible shaft ends. With regard to the magnet casing length there is a long measurement range. This allows a compact construction with a non-temperature-sensitive measurement principle. There is also a high linearity of correlation between position and measurement signal. An additional analysis device, using a sensor curve to increase the precision, can be dispensed with in this case. In a further embodiment of the invention, the field sensor comprises magnetoresistive elements, Hall effect sensors or field coils. For the measurement accuracy it may be desirable to change the magnetic field—although not during operation but in the context of certain configurations—in relation to that of a single magnet casing. In a further embodiment of the invention, the magnet casing consists of a magnetic material of preferably axially joined ring discs. The assembly of discs allows further variants. In a further embodiment of the invention, the ring discs consist of materials having a different remanence. If an assembly of discs is not desired, the magnet casing in a further embodiment of the invention is magnetized axially differently when consisting of a homogeneous magnetic material. In these forms of magnet casings, the measurement accuracy is considerably improved. In a further embodiment of the invention, the magnet casing, either consisting of a homogeneous material or assembled from ring discs has a ratio of diameter to length ranging from 2/3 to 3/2, preferably in the proximity of 1, so as to form a minimum field strength. In a further embodiment of the invention, the field sensors are arranged on the inner side of a casing-shaped screen. This screen may have a round or a square cross-section. In a further embodiment of the invention, the whole position sensor i.e. both the field sensors and the analysis electronics, are situated within the screen. This combination is extremely simple and flexible. In a further embodiment of the invention, the magnet casing is let into a ring-shaped recess of the rod-shaped component and the inlet casing is surrounded by a non-ferromagnetic shaft casing of greater length. The shaft casing can also be let into the rod-shaped component. In a further embodiment of the invention, the rod-shaped component is surrounded by a non-ferromagnetic linear guide casing, in the casing opening of which it can slide with the magnet casing, and the non-ferromagnetic linear guide casing is surrounded by a casing-shaped screen within which the field sensor is situated. In a further embodiment of the invention, the analysis electronics are arranged on the outer side of the screen and carry the sensors within the linear guide casing by means of a carrier guided through the screen. In a further embodiment of the invention, the rod-shaped component in the area of the measurement device consists of two parts connected together by means of a central pin arrangement, and the magnet casing and the shaft casing are pushed onto the rod-shaped component in the area of the pin arrangement. Thus, a very simple and suitable and compact measurement device is obtained which can be used favorably, in particular in the automotive sector. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be elucidated with reference to the drawings. FIG. 1 is a diagram of a device with a magnetic position sensor according to the invention with a rod-shaped component, the axial displacements of which are determined by means of a magnet casing surrounding the component and fixedly connected thereto and a field sensor unit in the magnetic field of the magnet casing, FIGS. 2 a and 2 b show curves of the measured angle on the path, FIG. 3 shows a magnet casing composed of several ring bodies, FIG. 4 is a cross-section of the measurement device with a screen, where the magnet casing consists of an axially homogeneous material or, as in FIG. 3, is assembled from several ring bodies, and where analysis electronics with field sensors are arranged within the screen, FIG. 5 is a diagram of the angle/path curve in the arrangement in FIG. 4 with a comparison of the measurement errors occurring during use of the different magnet casings, FIG. 6 shows a measurement device with a magnet casing integrated in the rod-shaped component and a very compact screened construction, FIG. 7 is a section taken on the line VII—VII in the device shown in FIG. 6 . DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a rod-shaped component, for example, the shaft 3 of a valve (not shown) which performs axial displacements. On the valve shaft 3 and fixedly connected thereto sits a magnet casing M which generates a magnetic field 4 made visible through the field lines 4 a . The field lines 4 a are lines of equal vector potential. A field sensor 5 , which determines the magnetic field 4 a prevailing around it, is arranged in the magnetic field 4 . Along the shaft axis z, the shaft performs z linear displacements, where it can also rotate about the shaft axis z. The magnet casing M has a length L. The external diameter of the magnet casing is given as D. r 0 is the distance of field sensor 5 from the shaft axis z. The magnetization direction of the magnet casing lies in the axial direction marked z. The field sensors 5 and analysis electronics (not shown in FIG. 1) together form a position sensor. The angle to be measured is φ mes . This is the angle of a magnetic field strength H in relation to the z-axis. The field sensor 5 emits field strength signals to analysis electronics (not shown), from which it determines the field angle which in turn corresponds ideally to the displacement path. FIG. 2 a shows in a solid-line curve 6 the measured field angle on the displacement path. The broken line 6 a below it is the ideal line. It should be noted that the curve is essentially rectilinear as a function of the displacement path in the selected range z mes which corresponds to around 80% of the magnet length. FIG. 2 b shows the measurement error in percent on the path with reference to a curve 7 showing that the measurement error in the range z mes is very low from around −0.4 to +0.4 (approx. 80% of the magnet length). This diagram shows the percentage measurement error Δφ mes on the displacement path z/L. FIGS. 2 a and 2 b show the situation in which no screening is required and present when the arrangement has been carefully selected. The magnet casing consists of an axially homogeneous material. In practice, it is often not possible to work without a screening, in particular when several measurement devices are operated in the immediate vicinity. Here the working results deteriorate. This deterioration can be compensated with an axially structured magnet casing M described with reference to FIG. 3 . FIG. 3 shows a magnet casing M comprising three ring bodies M 1 , M 2 and M 3 joined together. The structure is symmetrical i.e. the axial lengths L 1 , L 2 and L 3 are equal. Here, different dimensions may of course also be selected. There are various possibilities of structuring the ring bodies M 1 , M 2 , M 3 . One possibility is to make them of a fully magnetized material of different remanence. Another possibility would be to make the individual ring bodies M 1 , M 2 , M 3 of the same material and to magnetize them to different intensities. Another, preferable possibility is to use a magnet casing M of a uniform material and magnetize it to different intensities along the shaft axis z, using a suitable device. Further variants are also possible. Fewer than three ring bodies or more than three ring bodies are possible. To achieve a casing length which is favorable with regard to measurement accuracy and achievable minimum field strength, the magnet casing, either consisting of a homogeneous material with axially modified magnetization or assembled from ring discs (M 1 , M 2 , M 3 ) has a ratio of diameter to length ranging from 2/3 to 3/2, preferably in the proximity of 1, so as to form a minimum field strength. FIG. 4 shows how the measurement device can be screened from external fields. FIG. 4 shows the shaft 3 with shaft axis z. If a magnet casing M of an axially homogeneous material (version in which the broken separating lines M 4 must be ignored) sits on shaft 3 , then the broken-line measurement error curve shown in FIG. 5 applies, which although representative, is not desirable. If, however, an axially structured magnet casing M of the three different ring bodies M 1 , M 2 , M 3 as shown in FIG. 3 sits on shaft 3 , the measurement error can be compensated so that the solid-line error curve shown in FIG. 5 is obtained which particularly complies with the requirements. A screening plate 26 of a ferromagnetic material extends around the arrangement. The shaft 3 consists of a non-ferromagnetic or only a weakly ferromagnetic material. The whole position sensor with analysis electronics 11 on which the field sensor 5 is situated, is arranged on the inner side 26 a of the screening plate 26 . A connecting cable 8 transfers the position signals to a control device (not shown). The screening prevents interference fields from adjacent sensors or adjacent parts causing field distortions in the sensor area. In contrast to FIG. 4, the shaft 3 may also have the structure shown in FIG. 6 with the magnet casing M let into the shaft 3 . It is evident from the construction that the shaft 3 is freely rotatable in relation to the sensor without causing measurement value changes. FIG. 5 shows the diagram already indicated for percentage measurement errors. In the unscreened measurement device of FIG. 1, the broken-line error curve 9 is obtained. In the screened measurement device of FIG. 4, in which three magnetic ring bodies M 1 , M 2 , M 3 or an axially variable magnetization distribution are used, the solid-line error curve 10 is obtained. In the diagram, the percentage measurement error Δφ mes shown on the displacement path z/L, where the path is marked z mes . In the configurations with an axially variable material or an axially variable magnetization, the measurement inaccuracy is reduced clearly quite considerably as compared with that shown in FIG. 2 a. FIG. 6 shows another structure of the device in a longitudinal section. FIG. 7 is a cross-section of the device shown in FIG. 6, taken on the line VII—VII. The magnet casing M is let into a ring-shaped magnet recess 12 of the rod-shaped component 3 , for example, the valve shaft 3 . In this case, the magnet casing M may also consist of an axially homogeneous material, which is preferably structured axially magnetically, or it may consist of magnetic ring discs M 1 , M 2 , M 3 , where the number of three ring discs is merely an example. Similarly as in the other embodiments, only two or more than three ring discs may be used. The possible division into magnetic ring discs is indicated in FIG. 6 . The inlet magnet casing M is surrounded by a non-ferromagnetic shaft casing 13 of greater length. This shaft casing 13 is inserted on the magnet casing M into a cover recess 14 overlaying its magnet recess 12 . The outer wall 15 of the shaft casing 13 is preferably flush with the outer wall 16 of the valve shaft 3 . A linear guide casing 17 surrounds the valve shaft 3 shown in FIG. 6, which is freely displaceable and rotatable in the casing opening 18 . The linear guide casing 17 consists of a non-ferromagnetic material. The linear guide casing 17 is surrounded by a casing-shaped screen 19 on which the analysis electronics 11 of the field sensor 5 are arranged. The screen 19 has an opening 21 extended as a blind hole 22 into the linear guide casing 17 . Arranged on the analysis electronics 11 is a carrier 23 which retains the field sensor 5 in the blind hole 22 of the linear guide casing 17 . The valve shaft 3 within the shaft casing 13 has a central pin arrangement 24 which consists of a central pin 24 a and a central recess 24 b in which pin 24 a engages. If the valve shaft 3 is extended, the magnet casing or casings M and the shaft casing 13 can easily be pushed on. In all cases the field sensors 5 may be structured in known manner. It is possible to use paired magnetoresistive sensors, Hall effect sensors or field coils. FIG. 7 is a section taken on the line VI—VI in the device of FIG. 6 . The valve shaft 3 in the center of non-ferromagnetic or weakly ferromagnetic material is surrounded by the magnet casing or casings M, the shaft casing 13 and the linear guide casing 17 . The linear guide casing 17 is surrounded by the screen 19 . The analysis electronics 11 carry the field sensor 5 by means of carrier 21 . The distance of the displacement axis z to the sensor 5 is given as r 0 . Di is the internal diameter of magnet casing M. D is the external diameter of the magnet casing. Ds is the internal diameter of the screen 19 . L is the axial length of the magnet casing. L 1 , L 2 , L 3 are the lengths of the individual ring magnets M 1 , M 2 , M 3 which together form the total axial length of the magnet casing M. As an example of the device shown in FIGS. 6 and 7, the following dimensions can be given by way of example: r 0 =0.64D L=D Ds=2×D L 1 =L 2 =L 3 The magnetization of ring magnets M 1 and M 3 should be about 10% higher than the magnetization of M 2 .

4y

FIELD OF THE INVENTION The present invention provides an improved test device, method of making the device and method for the detection of bilirubin in serum. More particularly, a composition is provided which, when incorporated with a carrier to form a device, allows color to develop uniformly on the test device. BACKGROUND OF THE INVENTION In the breakdown of heme, bile pigments, principally bilirubin, are produced in the serum which are then removed by the liver. The amount of bile pigments formed each day is closely related to the amount of hemoglobin destroyed and liver function. It is estimated that 1 gram (g) of hemoglobin yields 35 milligrams (mg) of bilirubin. Normally 0.1 to 1.5 mg of bilirubin is present in 100 milliliters (ml) of human plasma or serum. Estimation of serum bilirubin has been recognized to be of great value in clinical studies, such as of liver dysfunction. A method for quantitatively assaying the bilirubin content of the serum was first devised by Van den Bergh by application of Ehrlich's test for bilirubin in urine. The Ehrlich reaction is based on the coupling of diazotized sulfanilic acid (Ehrlich's diazo reagent) and bilirubin to produce a reddish-purple azo compound. In the original procedure as described by Ehrlich, alcohol was used to provide a solution in which both bilirubin and the diazo reagent were soluble. Van den Bergh discovered that by omitting the alcohol when assaying for bile pigment in human bile normal development of the color occurred "directly", that is, without the addition of alcohol. This form of bilirubin which would react without the addition of alcohol was thus termed "direct-reacting." However, it was still necessary to add alcohol to detect bilirubin in normal serum. To that form of bilirubin which could be measured only after the addition of alcohol the term "indirect-reacting" was applied. The indirect bilirubin is "free" (unconjugated) bilirubin en route to the liver from the reticuloendothelial tissues where the bilirubin is produced by the breakdown of heme porphyrins. Since this bilirubin is not water-soluble it requires addition of alcohol to initiate coupling with the diazo reagent. In the liver the free bilirubin becomes conjugated with glucuronic acid. Conjugated bilirubin, being water-soluble, can react directly with the diazo reagent so the the "direct bilirubin" of Van den Bergh is actually a bilirubin conjugate (bilirubin glucuronide). Sulfonic acids other than sulfanilic acid have been suggested as acceptable in the diazo coupling reaction described. Such include p-toluenesulfonic acid, sulfosalicylic acid, sulfonic acid and hexamic acid. See, for example, U.S. Pat. No. 3,585,001. It has also been known that other substances besides alcohol exhibit the same influence, that is of enhancing the diazo coupling of "free" bilirubin, allowing for a measure of indirect, and thus total, bilirubin. These substances are referred to as "accelerating agents" and have included caffeine, dyphylline, sodium acetate, sodium benzoate, gum arabic and others. Reference is made to Henry, R. J., Clinical Chemistry, Principles and Technics, Second Edition, Harper and Row, pp. 1047 (1974); With, T.K., Bile Pigments, Academic Press, pp. 324-327 (1968); and U.S. Pat. No. 4,038,031. Test devices for bilirubin determination, such as in strip format, have been disclosed which make use of the diazo coupling reaction. See, for example, the above-identified patents as well as U.S. Pat. Nos. 3,853,476; 3,880,588; 3,912,457; 4,069,016; and 4,069,017. These devices have served a useful purpose in clinical diagnosis. It has now been recognized, however, that these prior art devices suffer from the drawback that they do not absorb serum specimens in a uniform manner. The color formed at the point of sample application is quite intense, whereas very little, if any, color is developed peripheral to this point. This non-uniformity is a particularly undesirable characteristic, since uniform color development is necessary to achieve the precision required for a quantitative test. This problem in prior art devices has, in accordance with the invention, been recognized and overcome as is fully described below. SUMMARY OF THE INVENTION It has now been found that a test device for detecting bilirubin in serum which comprises a carrier and, incorporated therewith, a composition comprising a diazonium salt, p-toluenesulfonic acid and dyphylline is free of the undesirable characteristic of nonuniformity of color development when reacted with a test sample. The presence of bilirubin in a serum sample is detected by a method which comprises contacting the device according to the invention with the sample to be tested and observing any resultant colorimetric response. The test device is prepared by a method which comprises incorporating, such as by saturation with an impregnating solution, a carrier with a composition as described above. The difficulties of nonuniformity which have now been overcome are believed to have been a result of serum protein precipitation in the prior art test devices. This theory is not, however, one on which the invention is necessarily predicated. Notwithstanding the ability of the p-toluenesulfonic acid to produce a pH sufficiently low to stabilize the diazonium compound, it is now possible by using the test device according to the invention to obtain uniform color development in response to serum bilirubin. As a result, highly quantitative instrumental reflectance values, corresponding to bilirubin concentration, can be obtained independent of the point of application of the serum sample to the test device. DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific terms used in the following description are intended to refer only the particular embodiments selected for illustration of the invention defined by the claims. Test devices intended for detection of serum bilirubin can use any aromatic diazonium salt which exclusively or preponderantly contains electron-attracting groups. Thus, for example, in the benzene series, the substituents can be nitro groups, halogen atoms, carboxyl groups, sulfonic acid residues, nitrile groups or quaternary ammonium groups. Electron-donating groups, for example alkoxy radicals, can also be present to a limited extent. Furthermore, diazotized naphthylamine and benzidine derivatives can also be used. Less suitable are benzene-diazonium salts which exclusively contain electron-donating groups, such as alkoxy, alkyl or arylamino radicals, because these react comparatively slowly with bilirubin. Such diazonium salts can be added directly or can be formed in situ by the reaction of members of the aniline series with a nitrite, such as is shown in the Example. Whether the diazonium salt is added directly as the salt, itself, or the salt is formed in situ, the diazonium salts of substituted and unsubstituted halobenzenes, particularly 2,4-dichlorobenzene, are preferred. Also, diazonium salts of nitro-substituted benzenes, such as p-nitrobenzene diazonium tetrafluoroborate are advantageously selected. The diazonium salts are present in the impregnation solution in concentrations of from about 0.02 grams/deciliter (g/dl) to about 2.0 g/dl, and preferably from about 0.05 g/dl to about 0.5 g/dl. The p-toluenesulfonic acid is used in the impregnation solution in concentrations of from about 0.5 g/dl to about 10.0 g/dl and preferably from about 1.0 g/dl to about 6.0 g/dl. The dyphylline is used in the impregnation solution in concentrations of from about 6.0 g/dl to about 14.0 g/dl, and preferably from about 8.0 g/dl to about 12.0 g/dl. The solvent used in preparing the impregnation solutions can be water, physiological solutions, suitable organic solvents or mixtures thereof. Various additional components can optionally be added. Such can include Gantrez AN-139 (a copolymer of methyl vinyl ether and maleic anhydride from GAF Corp., Chemical Products, N.Y., N.Y.). The reaction is preferably carried out at a relatively acid pH, such as from about pH 1 to about pH 5. Test devices of the invention are prepared by a method which comprises incorporating a carrier, such as a bibulous matrix, with the test composition. When this incorporation is by saturation with an impregnation solution, as previously defined, of the composition, the carrier so impregnated is then dried. In addition to impregnation, the devices of the present invention can be made by other suitable techniques such as printing or spraying the composition onto a substrate or matrix. The term carrier is envisioned to refer to bibulous and nonbibulous matrices which are insoluble in and maintain their structural integrity when exposed to water or physiological fluids. Suitable bibulous matrices which can be used include paper, cellulose, wood, synthetic resin fleeces, glass fiber, woven and nonwoven fabrics and the like. Nonbibulous matrices include organoplastic materials, such as polypropylene or the like. When a bibulous matrix is employed, the matrix is advantageously affixed by suitable means, such as double-faced adhesive tape, to an insoluble support member, such as an organoplastic strip, e.g. polystyrene, for ease of use. The test device is advantageously used by dropping a small amount of a test sample thereon or by otherwise introducing a test sample into the carrier matrix, whereby a detectable color change results when bilirubin is present. The test device can be used in the same way whether samples of plasma or serum are tested. The reacted devices can be read visually, but for more precise quantitation of the concentration of bilirubin detected, colorimetric readings of reacted devices are taken on a reflectance spectrophotometer. Reflectance readings can be obtained from commercially available spectrophotometers such as Beckman DK-2 Spectrophotometer, Beckman Instruments, Inc., Fullerton, California 92634 or Spectrocolorimeter SCF-1, Israel Electro-Optical Industry Ltd. (distributed in the U.S. by Broomer Research Corporation, Plainwell, Long Island, N.Y. 11803). The illustrative example set forth below will suggest various substitutions and changes to one skilled in the art which are contemplated as within the scope of the claims. EXAMPLE I In this example devices prepared according to the invention and devices incorporating other combinations of reagents were compared for uniformity of color development and, thus, reliability of bilirubin concentration data obtained. Six different impregnation solutions were prepared under ambient laboratory conditions in a solvent of 45.0 milliliters (ml) distilled H 2 O and 5.0 ml of a 10 g/dl solution of Gantrez AN-139 according to the formulations set forth in Table 1. The p-toluenesulfonic acid and sulfosalicylic acid, were purchased from Eastman Organic Chemicals, Rochester, N.Y. 14650. Hexamic acid was obtained from Abbott Laboratories, North Chicago, Illinois. The 1,5-napthalene disulfonic acid, disodium; 2,4-dichloroaniline; and sodium nitrite were standard reagent grade material. Dyphylline and caffeine were purchased from Aldrich Chemical Co., Inc., Milwaukee, Wisconsin 53233. TABLE I__________________________________________________________________________Components A B C D E F__________________________________________________________________________sulfosalicylic acid -- 3.5 g -- 3.5 g -- --hexamic acid -- -- -- -- 3.0 g 3.0 gp-toluenesulfonic acid 2.8 g -- 2.8 g -- -- --caffeine -- 5.0 g 5.0 g -- 5.0 g --dyphylline 5.0 g -- -- 5.0 g -- 5.0 g1,5-napthalene disulfonicacid, disodium 0.3 g 0.3 g 0.3 g 0.3 g 0.3 g 0.3 g2,4-dichloroaniline 0.0375 g 0.0375 g 0.0375 g 0.0375 g 0.0375 g 0.0375 gsodium nitrite 0.10 g 0.10 g 0.10 g 0.10 g 0.10 g 0.10 g__________________________________________________________________________ The reagents include 2,4-dichloroaniline and sodium nitrite which interreact in situ in the impregnation solution to form a 2,4-dichlorobenzene diazonium salt, in this case 2,4-dichlorobenzene diazonium 1,5-napthalene disulfonate. The solution having formulation A was used to prepare devices according to the invention. The solutions having formulations B through F were used to prepare other devices for the comparison. It was immediately observed that formulations C and E, combining caffeine with p-toluenesulfonic acid and hexamic acid, respectively, would not go into solution, and therefore could not even be suitably impregnated into the paper matrices used. Separate sheets of Eaton-Dikeman 205 filter paper (Eaton-Dikeman, Mount Holly Springs, Pa. 17065) were impregnated to saturation, each with one of the remaining impregnation solutions identified above. The sheets so impregnated were subjected to 60° C. in a standard laboratory oven until dry. These paper sheets, containing the dried residue of the various impregnation solutions, were then cut to 2.5 millimeters (mm) by 2.5 mm squares to form devices. The devices were then backed by double-faced adhesive tape and fixed thereby to plastic support members. The devices prepared to incorporate compositions having formulations A, B, D and F will be referred to as devices A, B, D and F, respectively. Serum samples pretested to contain 1 mg/dl of bilirubin were then applied, in volumes of about 30 μl, to different locations (central and peripheral) on each of the devices prepared. Readings of the chromogenic response were taken by reflectance spectrophotometry. The percent reflectance (%R) was read at 560 nanometers (nm) wavelength ninety (90) seconds after sample applications. The results obtained by performance of this experiment are set forth as %R values in Table 2. TABLE 2______________________________________Sample Position A B C D E F______________________________________Central 49.5 47.0 -- 46.8 -- --Peripheral 49.8 56.5 -- 58.2 -- --______________________________________ The %R of device F at 560 nm was so negligible as to be unreadable. It was readable however at 450 nm, which was its reflectance minimum, but readings at this wavelength are subject to variation responsive to the color of the serum itself and thus are unreliable. The results reported show a %R difference of 0.3 between the devices containing compositions of formulation A to which samples were applied centrally and peripherally. The %R difference between devices containing compositions of formulation B to which samples were applied centrally and perpherally is 9.5. The difference seen between the uniformity of reading in device A versus the nonuniformity of reading in device B is, in this comparison, a ratio of 1 to 31.7. The %R difference between devices containing compositions of formulation D to which samples were applied centrally and peripherally is 11.4. The difference seen between the uniformity of reading in device A versus the non-uniformity of reading in device D is a ratio of 1 to 38. As noted above, no results could even be obtained for devices having compositions with formulations C and E because impregnation solutions could not even be prepared. The %R readings in Table 2 for the various devices were mathematically extrapolated to bilirubin concentrations expressed as milligrams/deciliter (mg/dl). The %R values reported for device A are very similar and both essentially reflect detection of bilirubin at a concentration of 1.0 mg/dl, the accurate pretested value. The %R values reported for device B, 47.0 and 56.5 respectively, represent 1.0 mg/dl (accurate for the device B formulation) and a false negative (0 mg/dl). The %R values reported for device D represent 1.0 mg/dl and 0 mg/dl bilirubin, respectively. As in device B, substantial variation in bilirubin concentrations detected is observed depending on where on the device the serum was applied. The experimental results reported and analyzed above clearly indicate that color development is much more uniform and, thus, clinical data much more accurate, when determined using a device of the present invention. Although the invention has been described with a certain degree of particularity it is understood that numerous changes may be made without departing from the scope of the invention.

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RELATED APPLICATIONS [0001] None GOVERNMENT INTEREST [0002] None BRIEF DESCRIPTION [0003] Climate change, as evidenced by “global warming,” has been confirmed through multiple scientific studies. One study, conducted by Donna Ashizawa and Jonathan J. Cole, predicted, “Global temperatures may rise 3° C.±1.5° C., at the rate of 0.6°-0.80° C. per decade” (1994). i The European Environment Agency stated that global ocean water temperature has risen about 0.6° C. since 1870 due to climate change. ii Sea surface temperatures are typically found by models to increase by about 2.5° C. over each century of carbon dioxide doubling; results from a 1992 study show that Atlantic Ocean temperatures (at precise locations along a 24° N transatlantic section) at a depth of 1,100 meters increased at a rate of just about 1° C. per century. iii Climate change is still being thoroughly investigated, but projected effects include rising water levels, melting ice caps, altered wildlife populations, changing disease patterns, and more severe and frequent extreme weather conditions. iv [0004] Rising ocean temperature impacts weather, and may also impact biodiversity. This is because warmer water holds less oxygen. Low oxygen levels combined with higher carbon dioxide levels may cause some species' oxygen transport mechanisms to bind with carbon dioxide in place of oxygen; this would invariably make it more difficult for the organism to breathe. Species that have “energy intensive” forms of swimming, such as squid, may find temperature rise particularly detrimental for this reason. iv Further, even species without energy-intensive swimming (e.g., mollusks) may have an impaired ability to thrive in warmer water. Thus, it would be advantageous to have an inexpensive aquaculture apparatus that provides the ability to control and adjust water temperature. [0005] Until now, however, scientists have not had an inexpensive aquaculture apparatus to grow aquatic organisms and simulate the effects of water temperature change on organisms that may be affected by this change. I have designed, built, and tested such an apparatus. My test results confirm that this apparatus works well to provide an inexpensive apparatus to assess the impact of changes in water temperature on the growth of aquatic species. BRIEF DESCRIPTION OF THE DRAWINGS [0006] FIG. 1 provides an overview of one version of my apparatus. DETAILED DESCRIPTION [0007] Materials and Methods [0008] I illustrate an embodiment of a suitable apparatus in FIG. 1 . Referring to the numbered elements in FIG. 1 , element [ 1 ] is a refrigeration device. In my temperature stability test described below, I used a DANBY® MAITRE'D® 6-bottle thermoelectric wine cooler, commercially available from Danby Products, Inc., Findlay, Ohio, which operates at a temperature range of 39° F.-72° F. It is 11″ in width, 22″ in depth, and 17″ in height. [0009] The device [ 1 ] includes a door mechanism [ 2 ] that is used to open the refrigeration device to access its interior. Tight-fitting seals on 3 sides of the doorframe retain all cooling power and humidity levels. The door mechanism [ 2 ] includes a translucent glass front [ 3 ]. It is tinted for UV protection but also allows for easy interior viewing. [0010] The device [ 1 ] includes a refrigerating mechanism [ 4 ] that cools the interior of the wine cooler. The refrigeration mechanism must be chosen carefully, because my invention requires air to be continuously pumped into the interior space [ 5 ] of the refrigeration device. This air warms the interior space [ 5 ] of the refrigeration unit, and thus must be cooled to the desired temperature. Thus, to maintain the desired temperature, the refrigeration mechanism must have sufficient cooling capacity to compensate for the constant addition of warm air. The entire device is plugged into an outlet via a power cord [ 17 ]. [0011] The device [ 1 ] includes an interior space [ 5 ] where the aquaculture tanks and air diffusers are located. The device [ 1 ] also includes a hole or port [ 6 ] through which airline tubing [ 7 ] passes from the exterior of the refrigeration device [ 1 ] to the interior space [ 5 ]. This hole [ 6 ] allows the airline tubing [ 7 ] to pass through the side of the refrigeration device [ 1 ] rather than through the front door [ 2 ] of the refrigeration device [ 1 ], thereby increasing the amount of air that is retained in the device and minimizing heat loss via the door. In a preferred embodiment, one may create a port [ 6 ] through the side of the refrigeration device [ 1 ] using a power drill and a 3/16″ drill bit, sized to assure a snug fit for the airline tubing [ 7 ]. In a preferred embodiment, the airline tubing [ 7 ] is a 2.5′ length piece of LEE'S® standard clear plastic 3/16″-diameter flexible airline tubing for aquariums, commercially available from Lee's Aquarium and Pet Products, San Marcos, Calif. [0012] The exterior section of the airline tubing [ 7 ] is attached to a JW PET COMPANY® Fusion Air Pump 400 [ 8 ], commercially available from JW Pet Company, Inc., Arlington, Tex., which is located outside of the refrigeration device [ 1 ]. The air pump is also plugged into an outlet via a power cord [ 15 ]. The interior section of the airline tubing [ 7 ] is attached to a 2.5″ tall, 1.5″ diameter aquarium air diffuser [ 9 ], which receives airflow from the air pump [ 8 ] and converts it into air bubbles to oxygenate the aquaculture water. [0013] The air diffuser [ 9 ] is placed inside an aquaculture container [ 10 ] in the interior space [ 5 ] that holds both the aquaculture water and the aquaculture organisms. In order to keep the aquaculture water clean, a fluid exchange pipe [ 11 0 ] may optionally be used to draw dirty water from the aquaculture container [ 10 ], via a water pump [ 14 ], and another fluid exchange pipe [ 11 ,] may optionally be used to bring clean aquaculture water into the container. The water pump [ 14 ] is plugged into an outlet via a power cord [ 16 ]. [0014] In order to view and regulate the interior temperature of the refrigeration device [ 1 ], an electronic display and control panel [ 12 ] is located on the front of the door mechanism [ 2 ]. The display and control panel includes a temperature adjustment switch to regulate the refrigeration mechanism [ 4 ]. This switch may comprise a temperature ‘UP’ button (used to raise the interior refrigeration device temperature, e.g., in 1° increments), and a temperature ‘DOWN’ button (used to decrease the interior refrigeration device temperature e.g., in 1° increments). The control panel [ 12 ] may optionally include additional features such as a power button, a temperature display screen (shows the current temperature setting) or an interior light toggle button (used to manually illuminate or extinguish the interior lights while the door remains closed). [0015] A glass thermometer and hydrometer [ 13 ] is placed in the aquaculture container [ 10 ] in the water, to show both the actual water temperature and water salinity level (in parts per thousand) simultaneously, since the temperature displayed on the display and control panel [ 12 ] measures the ambient air temperature in the interior space [ 5 ] and does not always precisely match the actual temperature of the aquaculture water. [0016] Note that in the embodiment illustrated, the air pump is placed on the outside of the refrigeration device. As an alternative, the pump may be placed in the interior space [ 5 ] of the refrigeration device. These alternatives each present certain advantages and disadvantages. [0017] Placing the air pump in the interior space [ 5 ] of the refrigeration device means that electric power must be supplied to the interior space [ 5 ]. This may readily be done by, for example, installing an electric power outlet on the interior surface of the refrigeration device [ 1 ]. Alternatively, the air pump power cord [ 16 ] can be passed through the hole [ 6 ] in the refrigeration device [ 1 ]. Placing the air pump in the interior space [ 5 ] of the refrigeration device means the air in the refrigeration device re-circulates repeatedly through the aquaculture containers [ 10 ]. This may be advantageous if the organisms present a biohazard. This also eases water temperature control, because the air fed into the aquaculture containers [ 10 ] is the same temperature as the ambient air in the interior space [ 5 ] of the refrigeration device [ 1 ]. Recirculation of air, however, means that the organisms will gradually deplete the oxygen in the air. Thus, if the pump is placed in the interior space [ 5 ], one would need to monitor O 2 and CO 2 levels in the interior space [ 5 ] and add supplemental oxygen as needed. [0018] Placing the air pump exterior to the refrigeration device (as illustrated in FIG. 1 ) enables the pump to pump air directly from the surrounding environment into the refrigeration device interior, and thence into the water in the aquaculture containers. This placement is advantageous because it assures the aquaculture water will be adequately oxygenated with new oxygen, to thereby provide a suitably-oxygenated growth medium for the species there grown. This pump configuration, however, poses two demands on the system. [0019] First, the pump must be sited in a location which itself has adequate oxygen for aquaculture. For most purposes, location in a room with free air circulation is adequate. [0020] Second, placing the pump exterior to the refrigeration device [ 1 ] means that the system must be tuned to assure that it is able to maintain a constant water temperature. This is because the air pump [ 8 ] constantly adds to the interior space [ 5 ] air which is drawn from outside the refrigeration device [ 1 ]. That air is most likely at a temperature different from—and perhaps markedly different from—the temperature desired for the interior space [ 5 ]. Thus, the refrigeration mechanism [ 4 ] must be selected carefully to assure that it is adequately powered to cool the incoming air, and do so quickly enough to maintain the temperature of the water in the aquaculture container [ 10 ]. This calculation requires considering the volume of water in the aquaculture container [ 10 ], the oxygen consumption rate of the animals in that container, the air flow required to replace that oxygen, and the amount of heat per unit time that air introduces into the system (itself a function of the difference in temperature between the external air and the internal space [ 5 ]). Incorrectly tuning the system may result in a system which cannot achieve the desired temperature, or which cycles between the desired temperature and the ambient air temperature. EXAMPLE 1 [0021] Four DANBY® MAITRE'D® wine coolers were used to make the apparatus depicted in FIG. 1 . They were labeled (“A” through “D,” respectively). A nominal interior temperature for the interior space [ 5 ] was set using the temperature control panel [ 12 ]. [0022] Four 1-gallon polyethylene plastic containers were obtained; in each was placed thirty two (32) ounces of room temperature water. One such plastic container with water was then placed into each of the wine coolers (A-D). The ambient room air temperature was measured. The door [ 3 ] was then closed, and the system allowed to temperature stabilize for twelve hours. [0023] After twelve hours, temperature measurements were taken using a digital thermometer of the ambient room air temperature, the interior space [ 5 ] air temperature and the water temperature. Results are shown in Table 1. The first Column shows the label of the cooler. The next Column shows the nominal temperature, i.e., the temperature set using the temperature control panel [ 12 ] on the refrigerator apparatus [ 1 ]. The next Column shows the actual air temperature of the air in the interior space [ 5 ], as measured by a digital thermometer after the 12-hour stabilization period. The next Column shows the difference (in degrees Fahrenheit) between the nominal temperature and the actual air temperature. The next Column shows the water temperature for the water stored in the cooler, as measured by a digital thermometer after a 12-hour period. The next Column shows the difference between the nominal temperature set by the temperature control panel [ 12 ] and the actual water temperature achieved after twelve hours. The next Column shows the difference (in percent) between the nominal temperature and the actual water temperature observed after 12 hours. The final Column shows the difference (in percent) between the actual water temperature and the actual air temperature at 12 hours. [0000] TABLE 1 Water Air Variance Water Variance Variance From variance Nominal Air From Water From Nominal From Air Chiller Temp Temp Nominal Temp Nominal (%) (%) A 50 53.9 3.9 52.7 2.7 5.4% 2.2% B 55 60.8 5.8 59.0 4.0 7.2% 3.0% C 60 64.9 4.9 63.6 3.6 6.0% 2.0% D 65 65.3 0.3 64.5 0.5 0.8% 1.2% Temperatures are in degrees Fahrenheit. The ambient room air temperature was 65° F. at both commencement and after twelve hours. [0024] The above experimental protocol was repeated, producing the results shown in Table 2 . [0000] TABLE 2 Water Air Variance Water Variance Variance From variance Nominal Air From Water From Nominal From Air Chiller Temp Temp Nominal Temp Nominal (%) (%) A 50 50.1 0.1 52.1 2.1 4.2% 4.0% B 55 58.6 3.6 59.0 4.0 7.2% 0.7% C 60 63.8 3.8 64.0 4.0 6.7% 0.3% D 65 64.9 0.1 66.0 1.0 1.5% 1.7% Temperatures are in degrees Fahrenheit. The ambient room air temperature was 65° F. at both commencement and after twelve hours. [0025] These data provide insight into whether a device as simple as a conventional wine chiller can feasibly be used for controlling aquaculture temperature. [0026] One insight is that the particular wine chillers used, despite having a temperature-control panel [ 12 ], do not in fact control temperature particularly precisely. This insight can be derived from the fact that air has a far smaller heat capacity than does water; that is, for a given change in energy, air changes temperature much more rapidly than does water. If the temperature inside the unit [ 5 ] varies rapidly, then the air will equilibrate to this new temperature far more rapidly than does the water, thus creating a difference in temperature between air and water. The greater the difference between air temperature and the water temperature, the more rapid and more pronounced the change in appurtenant change in inside air temperature. [0027] The data show that the temperature-control panel provides a reasonably accurate measure of temperature. For example, Unit D was set to provide a nominal temperature equal to ambient room air temperature (i.e., 65° F.). After two twelve-hour stabilizations, the actual interior air temperature was 64.5° and 66.0° F.; not exactly the nominal temperature, but, on average, accurate enough to support aquaculture work. [0028] The data here also show that this system produces some inherent cycling of interior air temperature. This can be seen from Unit D, where the temperature of the ambient room air was the same as the desired nominal temperature of the water (i.e., 65° F.). This meant that the air pump provided a constant supply of fresh 65° F. ambient room air into the refrigerator interior [ 5 ]. One would expect this to potentially stabilize the temperature entirely, obviating the need for the refrigeration apparatus [ 4 ] to perform any thermal work. My actual results, however, did not bear this thesis out. Rather, in both trials, the temperature of the air in the interior space [ 5 ] for Unit D differed from the temperature of the water in the container [ 10 ], indicating the system had some amount of temperature cycling. [0029] The data here show that the greater the difference between the nominal temperature and the outside air temperature, the greater the degree of temperature cycling. This is shown by the results for Units A-C, in comparing the inside air temperature and the water temperature. These data indicate that the greater the difference between the outside air temperature and nominal temperature, the greater the change in inside air temperature over time, and the more rapid those temperature changes occur. [0030] These results suggests that to assure a relatively constant water temperature, one needs to use a large enough volume of water in the aquaculture container so that the water can act as a heat sink, providing a great enough heat capacity to resist temperature change in response to transient changes in inside air temperature. The 32 ounce water volume used here was adequate for this only when the nominal temperature was within perhaps 5° F. of the ambient room air temperature. Extrapolating from this, I believe using a full gallon of water (as would be necessary to provide adequate oxygen to support even a small number of animals) would provide quite stable water temperature. [0031] Overall, the apparatus proves a viable yet inexpensive way to control water temperatures in an experimental environment. While the actual water temperature often varies from the desired water temperature, after a few preliminary tests, these variabilities can be controlled for. [0032] i Ashizawa, D., & Cole, J. J. (1994, March). Long-term temperature trends of the Hudson River: A study of the historical data. Estuaries, 17(1, Part B), 166-171. Retrieved from http://www.jstor.org// [0033] ii Rising sea surface temperature: Towards ice free Arctic summers and a changing marine food chain. (2011, Apr. 13). Retrieved Jan. 3, 2012, from European Environment Agency website: http://www.eea.europa.eu/themes/coast_sea/sea-surface-temperature [0034] iii Parrilla, G., Lavin, A., Bryden, H., Garcia, M., & Millard, R. (1994). Rising temperatures in the subtropical north Atlantic Ocean over the past 35 years. Nature, 369, 48-51. doi:10.1038/369048a [0035] iv Harrould-Kolieb, E., & Savitz, J. (2009, June). Acid test: Can we save our oceans from CO 2? (Research Report). Oceana.

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CROSS-REFERENCES TO RELATED APPLICATIONS The present application is a continuation application of and claims priority to U.S. Non-Provisional patent application Ser. No. 10/402,844, filed on Mar. 28, 2003, which is a continuation of U.S. Non-Provisional patent application Ser. No. 09/149,920, filed on Jun. 24, 2003, the entire contents of which are herein incorporated by reference for all purposes. The following related commonly-owned copending application is hereby incorporated by reference in its entirety for all purposes: U.S. Non-Provisional patent application Ser. No. 09/149,921, filed on Sep. 9, 1998 entitled, “AUTOMATIC ADAPTIVE DOCUMENT HELP FOR PAPER DOCUMENTS.” Further, this application incorporates by reference the following commonly owned copending U.S. patent application in its entirety for all purposes: U.S. Non-Provisional patent application Ser. No. 08/995,616, filed Dec. 22, 1997, entitled “AUTOMATIC ADAPTIVE DOCUMENT HELP SYSTEM.” STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT Not Applicable REFERENCE TO A “SEQUENCE LISTING,” A TABLE, OR A COMPUTER PROGRAM LISTING APPENDIX SUBMITTED ON A COMPACT DISK Not Applicable BACKGROUND OF THE INVENTION The present invention relates to printing of electronic documents and more particularly to method and apparatus for augmenting the printing of electronic documents with features to enhance the experience of reading or using the hardcopy of an electronic document. Increasingly, readers of documents are being called upon to assimilate vast quantities of information in a short period of time. To meet the demands placed upon them, readers find they must read documents “horizontally,” rather than “vertically,” i.e., they must scan, skim, and browse sections of interest in multiple documents rather than read and analyze a single document from beginning to end. Documents are becoming more widely available in electronic form. Some documents are available electronically by virtue of their having been created using word processing software. Other electronic documents are accessible via the Internet. Yet others may become available in electronic form by virtue of being scanned in, copied, or faxed. Commonly assigned U.S. application Ser. No. 08/754,721, entitled AUTOMATIC AND TRANSPARENT DOCUMENT ARCHIVING, the contents of which are incorporated herein by reference for all purposes, details a system for generating electronic as well as hardcopy format of documents. However, the mere availability of documents in electronic form does not assist the reader in confronting the challenges of assimilating information quickly. Indeed, many time-challenged readers still prefer paper documents because of their portability and the ease of flipping through pages. Certain tools take advantage of the electronic form documents to assist harried readers. Tools exist to search for documents both on the Internet and locally. Once a document is identified and retrieved, automatic summarization techniques, such as the Reader's Helper™, described in a commonly owned copending U.S. patent application Ser. No. 08/995,616, entitled AUTOMATIC ADAPTIVE DOCUMENT HELP SYSTEM, the contents of which are incorporated herein by reference for all purposes, helps the reader to find as well as assimilate the information he or she wants more quickly. However, there is heretofore no automatic assistance available to the reader who desires to work with printed hardcopy of electronic documents. What is needed is a document printing system that helps the reader print the information he or she wants more quickly. The document printing system should be easily personalizable, flexible and adaptive as well. BRIEF SUMMARY OF THE INVENTION An automatic printing assistant application for documents in electronic form is provided by virtue of the present invention. In certain embodiments, an elongated thumbnail image of all or part of an electronically stored document is displayed. A section of the document of interest to the reader is emphasized. Movement of the emphasized area in the elongated thumbnail image assists the user with the selection of sections or pages of the document for printing. The operation of the assistant is personalizable for a particular user by setting of a sensitivity level and selection of relevant topics of interest. Some embodiments of the assistant are also capable of improved performance over time by both automatic and manual feedback. The assistant is usable with many popular electronic document formats. In accordance with a first aspect of the present invention, a method for adaptively controlling printing of an electronically stored document includes a step of accepting user input indicating a user-specified concept of interest. A step of analyzing the electronically stored document to identify locations of discussion of the user-specified concept of interest may also be included. Embodiments can also include a step of displaying visual indications of the identified locations. In another step, user input indicating a print preference for certain locations is accepted. Finally, portions of the electronic document corresponding to the user's print preferences are printed. In accordance with a second aspect of the present invention, the method for assisting a reader in printing an electronically stored document also includes a step of accepting user input indicating a print preference by emphasizing an area of interest to the user in a thumbnail image corresponding to a section of interest to the user in the document. The user can control printing by sliding the emphasized area through thumbnail image for the purposes of indicating sections of the electronically stored document to print. In select embodiments in accordance with the present invention, the method includes a step of displaying an elongated thumbnail image of a portion of the electronically stored document in a viewing area of a display. In certain embodiments in accordance with the present invention, the step of analyzing the electronically stored document to identify locations of discussion of the user-specified concept of interest may be realized by exploiting a probabilistic inference method, such as a Bayesian belief network or its equivalent to identify such locations. Numerous benefits are achieved by way of the present invention over conventional techniques. In some embodiments, the present invention is more user friendly than conventional techniques. The present invention can provide a way for the user to obtain hardcopy of only those sections of a large document which contain concepts of interest. Some embodiments according to the invention are more robust than known techniques. These and other benefits are described throughout the present specification and more particularly below. A further understanding of the nature and advantages of the inventions herein may be realized by reference to the remaining portions of the specification and the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a representative computer system suitable for implementing the present invention. FIG. 2 depicts a representative document printing dialog in accordance with a particular embodiment of the present invention. FIG. 3 depicts a simplified flowchart of representative process steps in accordance with a specific embodiment of the invention. FIG. 4 depicts a simplified flowchart of representative process steps in accordance with an alternative embodiment of the invention. FIG. 5 depicts a top-level software architectural diagram for automatic annotation in accordance with one embodiment of the present invention. FIGS. 6A-6C depict a detailed software architectural diagram for automatic annotation in accordance with one embodiment of the present invention. FIG. 7 depicts a representative Bayesian belief network useful in automatic annotation in accordance with one embodiment of the present invention. FIG. 8 depicts a user interface for defining a user profile in accordance with one embodiment of the present invention. FIGS. 9A-9B depict an interface for providing user feedback in accordance with one embodiment of the present invention. FIG. 10 depicts a portion of an HTML document processed in accordance with one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention provides a personalizable system for printing automatically annotated documents based upon concepts of interest to a particular user. An embodiment according to the present invention has been reduced to practice under the name Reader's Helper™. Computer System Usable for Implementing the Present Invention FIG. 1 depicts a representative computer system suitable for implementing the present invention. FIG. 1 shows basic subsystems of a computer system 10 suitable for use with the present invention. In FIG. 1 , computer system 10 includes a bus 12 which interconnects major subsystems such as a central processor 14 , a system memory 16 , an input/output controller 18 , an external device such as a printer 20 via a parallel port 22 , a display screen 24 via a display adapter 26 , a serial port 28 , a keyboard 30 , a fixed disk drive 32 and a floppy disk drive 33 operative to receive a floppy disk 33 A. Many other devices may be connected such as a scanner 34 via I/O controller 18 , a mouse 36 connected to serial port 28 or a network interface 40 . Many other devices or subsystems (not shown) may be connected in a similar manner. Also, it is not necessary for all of the devices shown in FIG. 1 to be present to practice the present invention, as discussed below. The devices and subsystems may be interconnected in different ways from that shown in FIG. 1 . The operation of a computer system such as that shown in FIG. 1A is readily known in the art and is not discussed in detail in the present application. Source code to implement the present invention may be operably disposed in system memory 16 or stored on storage media such as a fixed disk 32 or a floppy disk 33 A. Image information may be stored on fixed disk 32 . Annotated Document Printing User Interface FIG. 2 depicts a representative user interface 200 in accordance with a particular embodiment of the invention. The representative user interface of FIG. 2 includes a print dialog 200 which provides the user with the capability to control the printing of an annotated document. As will be explained further below, an automatic annotation system according to the present invention adds annotations to any document available in electronic form. The document need not include any special information to assist in locating discussion of concepts of interest. These annotations denote text relevant to user-selected concepts. The print dialog 200 enables the user to obtain printed copy of sections of an electronically stored document having the greatest relevance to the concepts of interest to the user. An elongated thumbnail image 214 of many pages, or all of an electronically stored document 502 of FIG. 5 is presented in viewing area 215 . Elongated thumbnail image 214 provides a convenient view of the basic document structure. The annotations incorporated into the document are visible within elongated thumbnail image 214 . Within elongated thumbnail image 214 , an emphasized area 214 A shows a highlighted view of a portion of 502 the document. Thus, a user 504 may change the window size, causing emphasized area 214 A to change in size accordingly. The greater the viewing area allocated to elongated thumbnail image 214 and emphasized area 214 A, the more detail is visible. With very small allocated viewing areas, only sections of the document may be distinguishable. As the allocated area increases, individual lines and eventually individual words become distinguishable. Emphasized viewing area 214 A may be understood to be a lens or a viewing window over the part of elongated thumbnail image 214 corresponding to the document section of greatest interest to user 504 . User 504 may scroll through elongated thumbnail 214 by sliding emphasized area 214 A through elongated thumbnail 214 using mouse 36 or keys on keyboard 30 . As emphasized area 214 A shifts, the section of document 502 displayed in elongated thumbnail visible through emphasized area 214 A will also shift. The elongated thumbnail image 214 in FIG. 2 displays each page of document 502 as being displayed at the same reduced scale. In FIG. 2 , the user-configured ratio is approximately 6:1. The present invention also contemplates other modes of scaling elongated thumbnail image 214 . For example, one may display emphasized area 214 A at a scale similar to that shown in FIG. 2 and use a variable scale for the rest of elongated thumbnail image 214 . Text from far away emphasized area 214 A would be displayed at a highly reduced scale and the degree of magnification would increase with nearness to emphasized area 214 A. The annotations in elongated thumbnail image 214 make it very easy to find relevant text anywhere in document 502 . Furthermore, elongated thumbnail image 214 provides a highly useful way of keeping track of a lengthy document. These features enable the user 504 to readily locate portions of the document for printing. A series of concept indicators 206 permit the user to view which concepts of interest are to be noted in the document. Concepts are defined by means of a defined concepts list 806 shown in FIG. 8 , which lists all of the concepts which have been added to a user profile. By selecting a concept add button 808 , the user may add a new concept. The user profile is discussed below in greater detail. A sensitivity control 208 permits the user to select the degree of sensitivity to apply in identifying potential locations of relevant discussion for printing. At low sensitivity, more locations will be denoted as being relevant, even though some may not be of any actual interest. At high sensitivity, most all denoted locations will in fact be relevant but some other relevant locations may be missed. After each concept name appearing by one of concept indicators 206 appears a percentage giving the relevance of the currently viewed document to the concept. These relevance levels offer a quick assessment of the relevance of the document to the selected concepts. Miscellaneous printing options are found on a printing options button bar 216 . Printing Assistance FIG. 3 depicts a representative flowchart 301 of simplified process steps in a particular embodiment of the computer-implemented method for controlling printing of an electronically stored document according to the present invention. In a step 302 , user input indicating user-specified concepts of interest is accepted. Then, in a step 304 , the electronically stored document 504 is analyzed in order to identify locations of discussion of the user-specified concepts of interest input in step 302 . The analysis step 304 is detailed in FIG. 5 and the accompanying text below. Next, in a step 306 , visual indications of the locations identified in step 304 are displayed to the user. In a step 308 , user input indicating a print preference among the locations identified in step 304 is accepted. Finally, in a step 310 , portions of the electronic document corresponding to the user's print preference and the locations discussing the user's concepts of interest are printed. FIG. 4 depicts a representative flowchart 401 of simplified process steps in a particular embodiment of the computer-implemented method for controlling printing of an electronically stored document according to the present invention. In a step 402 , user input indicating user-specified concepts of interest is accepted. Then, in a step 404 , the electronically stored document 504 is analyzed in order to identify locations of discussion of the user-specified concepts of interest input in step 402 . Next, in a step 406 , visual indications of the locations identified in step 404 are displayed to the user 504 by means of an elongated thumbnail image of a portion of the electronically stored document 502 in a viewing area of a display. Then, in a step 408 , an area of a thumbnail image corresponding to a section of interest of electronically stored document 502 is emphasized in order to form an emphasized area. In a step 410 , input from user 504 controlling sliding of the emphasized area formed in step 408 through the thumbnail image is accepted for the purpose of indicating sections of electronically stored document 504 to print. Finally, in a step 412 , portions of the electronic document corresponding to the user's print preference and the locations discussing the user's concepts of interest are printed. In a particular embodiment, user 504 uses a sensitivity control 208 to select the degree of sensitivity to apply in identifying potential locations of relevant discussion. At low sensitivity, more locations will be denoted as being relevant, even though some may not be of any actual interest. At high sensitivity, most all denoted locations will in fact be relevant but some other relevant locations may be missed. Automatic Annotation Software FIG. 5 depicts a top-level software architectural diagram for analyzing electronically stored document 502 in accordance with step 304 of FIG. 3 and step 404 of FIG. 4 . The method for analyzing electronically stored document 502 is more fully detailed in a commonly owned copending U.S. patent application Ser. No. 08/995,616, entitled AUTOMATIC ADAPTIVE DOCUMENT HELP SYSTEM, which is incorporated herein by reference in its entirety for all purposes. Document 502 is stored in an electronic format. It may have been scanned in originally. It may be, e.g., in HTML, Postscript, LaTeX, other word processing or e-mail formats, etc. The description that follows assumes an HTML format. However, other formats may be used without departing from the scope of the present invention. A user 504 accesses document 502 through a document browser 506 , an annotation agent 508 or elongated thumbnail 214 of printing dialog 200 . Document browser 506 is preferably a hypertext browsing program such as Netscape Navigator™ or Microsoft Internet Explorer™ but also may be, e.g., a conventional word processing program. Annotation agent 508 adds the annotations to document 502 to prepare it for viewing by document browser 506 and printing by printing dialog 200 . Processing by annotation agent 508 may be understood to be in three stages, a text processing stage 510 , a content recognition stage 512 , and a formatting stage 514 . The input to text processing stage 510 is raw text. The output from text processing stage 510 and input to content recognition stage 512 is a parsed text stream, a text stream with formatting information such as special tags around particular words or phrases removed. The output from content recognition stage 512 and input to formatting stage 514 is an annotated text stream. The output of formatting stage 514 is a formatted text file which may be printed using print dialog 200 or viewed with document browser 506 . The processing of annotation agent 508 is preferably a run-time process. The annotations are not preferably pre-inserted into the text but are rather generated when user 504 requests document 502 for browsing. Thus, this is preferably a dynamic process. Annotation agent 508 may also, however, operate in the background as a batch process. The annotation added by annotation agent 508 depends on concepts of interest selected by user 504 . User 504 also inputs information used by annotation agent 508 to identify locations of discussion of concepts of interest in document 502 . In a preferred embodiment, this information defines the structure of a Bayesian belief network. The concepts of interest and other user-specific information are maintained in a user profile file 516 . User 504 employs a profile editor 518 to modify the contents of user profile file 516 . FIG. 6A depicts the automatic annotation software architecture of FIG. 5 with text processing stage 510 shown in greater detail. FIG. 6A shows that the source of document 502 may be accessed via a network 602 . Possible sources include e.g., the Internet 604 , an intranet 606 , a digital copier 608 that captures document images, or other office equipment 610 such as a fax machine, scanner, printer, etc. Another alternative source is the user's own hard drive 32 . Text processing stage 510 includes a file I/O stage 612 , an updating stage 614 , and a language processing stage 616 . File I/O stage reads the document file from network 602 . Updating stage 614 maintains a history of recently visited documents in a history file 618 . Language processing stage 616 parses the text of document 502 to generate the parsed text output of text processing stage 510 . FIG. 6B depicts the automatic annotation software architecture of FIG. 5 with content recognition stage 512 shown in greater detail. A pattern identification stage 620 looks for particular patterns in the parsed text output of text processing stage 510 . The particular patterns searched for are determined by the contents of user profile file 516 . Once the patterns are found, annotation tags are added to the parsed text by an annotation tag addition stage 622 to indicate the pattern locations. In a preferred HTML embodiment, these annotation tags are compatible with the HTML format. However, the tagging process may be adapted to a document preparation system such as LaTeX™, Postscript™, etc. A profile updating stage 624 monitors the output of annotation tag addition stage 622 and analyzes text surrounding the locations of concepts of interest. As will be further discussed with reference to FIG. 7 changes the contents of user profile file 516 based on the analysis of this surrounding text. The effect is to automatically refine the patterns searched for by pattern identification stage 620 to improve annotation performance. FIG. 6C depicts the automatic annotation software architecture of FIG. 5 with formatting stage 514 shown in greater detail. Formatting stage 514 includes a text rendering stage 626 that formats the annotated text provided by content recognition stage 512 to facilitate viewing by document browser 506 and printing by print dialog 200 . Pattern identification stage 620 looks for keywords and key phrases of interest and locates relevant discussion of concepts based on the located keywords. The identification of keywords and the application of the keywords to locating relevant discussion is preferably accomplished by reference to a belief system. The belief system is preferably a Bayesian belief network. FIG. 7 depicts a portion of a representative Bayesian belief network 700 implementing a belief system as used by pattern identification stage 622 . A first oval 702 represents a particular user-specified concept of interest. Other ovals 704 represent subconcepts related to the concept identified by oval 702 . Each line between one of subconcept ovals 704 and concept oval 702 indicates that discussion of the subconcept implies discussion of the concept. Each connection between one of subconcept ovals 704 and concept oval 702 has an associated probability value indicated in percent. These values in turn indicate the probability that the concept is discussed given the presence of evidence indicating the presence of the subconcept. Discussion of the subconcept is in turn indicated by one or more keywords or key phrases (not shown in FIG. 7 ). The structure of Bayesian belief network 700 is only one possible structure applicable to the present invention. For example, one could employ a Bayesian belief network with more than two levels of hierarchy so that the presence of subconcepts is suggested by the presence of “subsubconcepts” and so on. In the preferred embodiment, presence of a keyword or key phrase always indicates presence of discussion of the subconcept but it is also possible to configure the belief network so that presence of a keyword or key phrase suggests discussion of the subconcept with a specified probability. The primary source for the structure of Bayesian belief network 700 including the selection of concepts, keywords and key phrases, interconnections, and probabilities is user profile file 516 . In a preferred embodiment, user profile file 516 is selectable for both editing and use from among profiles for many users. The structure of belief system 700 is modifiable during use of the annotation system. The modifications may occur automatically in the background or may involve explicit user feedback input. The locations of concepts of interest determined by pattern identification stage 620 are monitored by profile updating stage 624 . Profile updating stage 624 notes the proximity of other keywords and key phrases within each analyzed document to the locations of concepts of interest. If particular keywords and key phrases are always near a concept of interest, the structure and contents of belief system 700 are updated in the background without user input by profile updating stage 624 . This could mean changing probability values, introducing a new connection between a subconcept and concept, or introducing a new keyword or key phrase. User 504 may select a word or phrase in document 502 as being relevant to a particular concept even though the word or phrase has not yet defined to be a keyword or key phrase. Belief system 700 is then updated to include the new keyword or key phrase. User 504 may also give feedback for an existing key word or key phrase, indicating the perceived relevance of the keyword or key phrase to the concept of interest. If the selected keyword or key phrase is indicated to be of high relevance to the concept of interest, the probability values connecting the subconcept indicated by the selected keywords or key phrases to the concept of interest increases. If, on the other hand, user 504 indicates the selected keywords or key phrases to be of little interest, the probability values connecting these keywords or key phrases to the concept decrease. User Profile and Feedback Interfaces FIG. 8 depicts a user interface for defining a user profile in accordance with one embodiment of the present invention. User interface screen 800 is provided by profile editor 518 . A profile name box 802 permits the user to enter the name of the person or group to whom the profile to be edited is assigned. This permits the annotation system according to the present invention to be personalized to particular users or groups. A password box 804 provides security by requiring entry of a correct password prior to profile editing operations. A defined concepts list 806 lists all of the concepts which have already been added to the user profile. By selecting a concept add button 808 , the user may add a new concept. By selecting a concept edit button 810 , the user may modify the belief network as it pertains to the listed concept that is currently selected. By selecting a remove button 812 , the user may delete a concept. If a concept has been selected for editing, its name appears in a concept name box 813 . The portion of the belief network pertaining to the selected concept is shown in a belief network display window 814 . Belief network display window 814 shows the selected concept, the subconcepts which have been defined as relating to the selected concept and the percentage values associated with each relationship. The user may add a subconcept by selecting a subconcept add button 815 . The user may edit a subconcept by selecting the subconcept in belief network display window 814 and then selecting a subconcept edit button 816 . A subconcept remove button 818 permits the user to delete a subconcept from the belief network. Selecting subconcept add button 815 causes a subconcept add window 820 to appear. Subconcept add window 820 includes a subconcept name box 822 for entering the name of a new subconcept. A slider control 824 permits the user to select the percentage value that defines the probability of the selected concept appearing given that the newly selected subconcept appears. A keyword list 826 lists the keywords and key phrases which indicate discussion of the subconcept. The user adds to the list by selecting a keyword add button 828 which causes display of a dialog box (not shown) for entering the new keyword or key phrase. The user deletes a keyword or key phrase by selecting it and then selecting a keyword delete button 830 . Once the user has finished defining the new subconcept, he or she confirms the definition by selecting an OK button 832 . Selection of a cancel button 834 dismisses subconcept add window 820 without affecting the belief network contents or structure. Selection of subconcept edit button 816 causes display of a window similar to subconcept add window 820 permitting redefinition of the selected subconcept. By determining whether a background learning checkbox 836 has been selected, the user may enable or disable the operation of profile updating stage 624 . A web autofetch check box 838 permits the user to select whether or not to enable an automatic web search process. When this web search process is enabled, whenever a particular keyword or key phrase is found frequently near where a defined concept is determined to be discussed, a web search tool such as AltaVista™ is employed to look on the World Wide Web for documents containing the keyword or key phrase. A threshold slider control 840 is provided to enable the user to set a threshold relevance level for this autofetching process. FIGS. 9A-9B depict a user interface for providing feedback in accordance with one embodiment of the present invention. User 502 may select any text and call up a first feedback window 902 . The text may or may not have been previously identified by the annotation system as relevant. In first feedback window 902 shown in FIG. 9A , user 504 may indicate the concept to which the selected text is relevant. First feedback window 902 may not be necessary when adjusting the relevance level for a keyword or key phrase that is already a part of belief network 700 . After the user selects a concept in first feedback window 902 , a second feedback window 904 is displayed for selecting the degree of relevance. Second feedback window 904 in FIG. 9B provides three choices for level of relevance: good, medium (not sure), and bad. Alternatively, a slider control could be used to set the level of relevance. If the selected text is not already a keyword or key phrase in belief network 700 , a new subconcept is added along with the associated new keyword or key phrase. If the selected text is already a keyword or key phrase, above, probability values within belief system 622 are modified appropriately in response to this user feedback. FIG. 10 depicts a portion of an HTML document 1000 processed in accordance with one embodiment of the present invention. A sentence including relevant text is preceded by an a <RH.ANOH.S . . . > tag 1002 and followed by an </RH.ANON.S> tag 1004 . The use of these tags facilitates the annotation mode where complete sentences are highlighted. The <RH.ANOH.S . . . > tag 1002 includes a number indicating which relevant sentence is tagged in order of appearance in the document. Relevant text within a so-tagged relevant sentence is preceded by an <RH.ANOH . . . > tag 1006 and followed by an </RH.ANOH> tag 1008 . The <RH.ANOH . . . > 1006 tag include the names of the concept and subconcept to which the annotated text is relevant, an identifier indicating which relevant sentence the text is in and a number which identifies which annotation this is in sequence for a particular concept. An HTML browser that has not been modified to interpret the special annotation tags provided by the present invention will ignore them and display the document without annotations. Software Implementation In a preferred embodiment, software to implement the present invention is written in the Jave™ computer programming language. Preferably, the software forms a part of a stand-alone browser program written in the Jave™ language. Alternatively, the code may be in the form of a so-called “plug-in” operating with a Jave™ -equipped web browser used to browse HTML documents including the special annotation tags explained above. In the foregoing specification, the invention has been described with reference to specific exemplary embodiments thereof. For example, any probabilistic inference method may be substituted for a Bayesian belief network. It will, however, be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the appended claims and their full scope of equivalents.

4y

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a Divisional application of prior application Ser. No. 13/495,461 filed on Jun. 13, 2012, the entire contents of the above of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention generally relates to an in-line sealed electrical connector apparatus having a connector apparatus position assurance device, and a locking method thereof. More particularly, this invention is directed to the connector apparatus position assurance device having contiguous parts for ensuring the engagement of the male and female connector assemblies of the in-line sealed electrical connector apparatus, and a locking method thereof. [0004] 2. Discussion of the Relevant Art [0005] U.S. Pat. No. 7,465,192 is directed to an in-line electrical connector apparatus that has a female connector assembly, the female connector assembly having a female housing, a female wire seal, and a female cover. The in-line sealed electrical connector of U.S. Pat. No. 7,465,192 further has a male connector assembly, the male connector assembly having a male housing, a retention clip, a male housing seal defining a male housing seal opening, a male wire seal, and a male cover. The female connector assembly is inserted within the male connector assembly, the female connector assembly being latched into the male connector assembly. [0006] When the in-line electrical connector apparatus is in use, a first wire assembly is connected to the female connector assembly, while a second wire assembly is connected to the male connector assembly. [0007] However, in the in-line electrical connector apparatus of U.S. Pat. No. 7,465,192, there is no assurance that the male housing assembly and the female housing assembly remain engaged and locked. SUMMARY OF THE INVENTION [0008] To ensure that the male housing assembly and the female housing assembly of the in-line sealed electrical connector apparatus of the present invention remain engaged and locked, a connector apparatus position assurance device is employed. The connector apparatus position assurance device has contiguous parts that engage various parts of the retention clip of the male connector assembly at different levels of insertion of the connector apparatus position assurance device into the male connector assembly. The insertion of the connector apparatus position assurance device is also accomplished at various stages (e.g., from pre-lock position to final lock position) dependent on the insertion level of the female connector assembly into the male connector assembly. For example, the effect of the level of insertion of the female connector assembly on various parts of the retention clip in turn affect the insertion of the connector apparatus position assurance device into the male connector assembly (i.e., from pre-lock position to final lock position). Also, if, e.g., the connector apparatus position assurance device happens to be fully inserted and in the final lock position, without the female connector assembly having been fully mated with the male connector assembly, the female connector assembly cannot be inserted into the male connector assembly. [0009] Once fully inserted, the connector apparatus position assurance device ensures the locking engagement of the male and female connector assemblies of the in-line sealed electrical connector apparatus of the present invention. This is accomplished by the connector apparatus position assurance device of this invention ensuring that the retention clip of the male connector assembly fully locks therein the female connector assembly. BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1 is an exploded perspective view of the in-line sealed electrical apparatus having a connector apparatus position assurance device of the present invention. [0011] FIG. 2A is side elevation view showing a first side of the connector apparatus position assurance device of the present invention; FIG. 2B is a side elevation view showing a second side, opposite the first side, of the connector apparatus position assurance device of the present invention; and FIG. 2C is an elevation view showing an end side of the connector apparatus position assurance device of the present invention. [0012] FIG. 3 is a perspective view of a retention clip of the male connector assembly showing the different parts thereof, which affect the insertion of the connector apparatus position assurance device of the present invention. [0013] FIG. 4 illustrates a perspective view of the connector apparatus position assurance device, in a pre-lock position, in which a lowered inner retention clip finger and a raised outer retention clip finger block the connector apparatus position assurance device from being inserted. [0014] FIG. 5 illustrates a perspective view of the connector apparatus position assurance device, still in a pre-lock position, in which the inner retention clip finger is raised, but the raised outer retention clip finger continues to block the connector apparatus position assurance device from being inserted. [0015] FIG. 6 illustrates a perspective view of the connector apparatus position assurance device in which the inner retention clip finger is raised, while the outer retention clip finger is lowered for allowing the connector apparatus position assurance device to be finally unblocked and ready to be inserted. [0016] FIG. 7 illustrates a perspective view of the connector apparatus position assurance device in a fully inserted position and in a final lock position. [0017] FIG. 8 is a perspective view of the connector apparatus position assurance device, in a full insertion position and final lock position, for completing the locking of the male and female connector assemblies of the in-line sealed electrical connector apparatus of this invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0018] FIG. 1 is an exploded view showing the in-line sealed electrical connector apparatus of the present invention, generally referred to as reference number 1 . The in-line electrical connector apparatus 1 includes a male connector assembly 3 and a female connector assembly 5 . Mounted within the male connector assembly 3 is a retention clip 7 for receiving therein the female connector assembly 5 . Shown in FIG. 1 is a connector apparatus position assurance device 8 insertable into the male connector assembly 3 and the retention clip 7 . The male connector assembly 3 has, at an end portion thereof, a cover 10 . A wire assembly (not shown) can be inserted into the male connector assembly 3 through openings (not shown) passing through the cover 10 ; and another wire assembly (not shown) can similarly be inserted into the female connector assembly 5 through openings (not shown) at a free end 6 thereof. [0019] The male connector assembly 3 has slots 12 , 14 passing therethrough for accommodating therein protrusions 20 , 22 extending from an upper side of the retention clip 7 . Slots 16 , 18 , opposed to the slots 12 , 14 , are for accommodating therein protrusions (not shown) extending from a lower side of the retention clip 7 , the lower side of the retention clip 7 being opposed to the upper side of the retention clip 7 . [0020] The cover 10 of the male connector assembly 3 has an upper slot 25 passing through an upper side of the cover 10 and a lower slot 27 passing through a lower side of the cover 10 . The upper slot 25 is for accommodating therein a protrusion 30 extending from an upper side of the male connector assembly 3 , while the lower slot 27 is for accommodating therein a protrusion (not shown) extending from a lower side of the male connector assembly 3 . The cover 10 includes an elongated slot 28 extending along an inner surface thereof for accommodating therein an elongated protruding member 29 extending along a side portion of the male connector assembly 3 , the elongated slot 28 being used to slidably guide the elongated protruding member 29 when the cover 10 is slidably mounted on an end portion of the male connector assembly 3 . [0021] As also illustrated in FIG. 1 , the male connector assembly 3 has a lever arm 50 with a fixed end 51 and a free end 52 . The free end 52 of the lever arm 50 includes an inner protruding member 54 , the inner protruding member 54 having an upper substantially inclined surface 55 and a lower substantially flat surface 56 . The fixed end 51 of the lever arm 50 is connected to the lower side of the male connector assembly 3 via a member 53 (generally, an L-shaped member). See, also, FIG. 8 . [0022] The retention clip 7 includes a lower side 32 and an upper side 34 . An inside portion of the lower side 32 of the retention clip 7 includes an elongated slot 30 which accommodates therein an elongated protrusion (not shown) extending from a lower side of the female connector assembly 5 , the elongated slot 30 guiding the elongated protrusion of the female connector assembly 5 when the female connector assembly 5 is inserted into the retention clip 7 once the retention clip 7 is mounted inside the male connector assembly 3 . See, also, FIG. 3 . [0023] Further, as also illustrated in FIG. 1 , the upper side 34 the retention clip 7 includes a pair of flexible fingers 36 , 38 ; namely an inner finger 36 and an outer finger 38 , the outer finger 38 having the protrusion 20 thereon (discussed earlier). [0024] As later discussed, when the retention clip 7 is fully inserted and mounted within the male connector assembly 3 , the inner protruding member 54 of the free end 52 of the lever arm 50 is placed within a space 60 between end portions of the lower side 32 and the outer finger 38 of the retention clip 7 , the inner protruding member 54 of the lever arm 50 being wedged within the space 60 to prevent the outer finger 38 from moving downward (and the protrusions 20 , 22 from being dislodged from the slots 12 , 14 ) and to keep the retention clip 7 fully mounted and locked within the male connector assembly 3 . Also, the lever arm 50 is kept from moving (and therefore the inner protruding member 54 of the lever arm 50 from moving away from the slot 60 ) by a bar 62 connected at a side of the male connector assembly 3 . [0025] As further shown in FIG. 1 , the female connector assembly 5 includes, on an upper surface thereof, an elongated slot 40 for accommodating therein the outer finger 38 of the retention clip 7 when the female connector assembly 5 is fully inserted within the retention clip 7 , as more fully discussed later. [0026] The connector apparatus position assurance device 8 has leading end members 70 , 72 ; namely, a first leading end member 70 and a second leading end member 72 , the first leading end member 70 extending longer from the base end 75 of the connector apparatus position assurance device 8 than the second leading end member 72 . As better shown in FIG. 2B and FIG. 2C , the axis of elongation of the second leading end member 72 is positioned below and to the side relative to the axis of elongation of the first leading end member 70 . [0027] As further illustrated in FIG. 1 , the connector apparatus position assurance device 8 also has an elongated aperture 77 passing through a lower portion thereof, a pair of protrusions 79 extending downward from a bottom elongated member 81 thereof (see, FIG. 2A ), and an elongated protrusion 80 extending from a side thereof. When the apparatus position assurance device 8 is inserted into the male connector assembly 3 , the elongated protrusion 80 is slidably accommodated and partially guided within a corresponding elongated slot (not shown) within an inner surface of the male connector assembly 3 (more particularly, the inner surface of the lever 50 of the male connector assembly 3 ). [0028] Also, the bottom elongated member 81 , below the elongated aperture 77 , acts as a flexible cantilever, and flexes when the pair of protrusions 79 slide over the generally L-shaped member 53 when the apparatus position assurance device 8 is inserted into the male connector assembly 3 . The pair of protrusions 79 , along with the generally L-shaped member 53 , act as additional assurance for ensuring that the apparatus position assurance device 8 is securely in place, in final lock position, when fully inserted into the male connector assembly 3 . [0029] FIGS. 2A , 2 B, and 2 C illustrate the connector apparatus position assurance device 8 of the invention, in more detail, with FIG. 2A being a side elevation view showing a first side of the connector apparatus position assurance device 8 , FIG. 2B being a side elevation view showing a second side, opposite the first side, of the connector apparatus position assurance device 8 , and FIG. 2C being an elevation view showing an end side of the connector apparatus position assurance device 8 . Shown in FIG. 2B is the second leading end member 72 having the axis of elongation being positioned below and to the side relative to the axis of elongation of the first leading end member 70 resulting in a ledge-like surface 90 on an upper surface of the second leading end member 72 (see, FIG. 2B ). [0030] Further illustrated in FIG. 2B is a slot 92 formed on a side surface of the base end 75 of the connector apparatus position assurance device 8 . The slot 92 (see, also, FIG. 2C ), which accommodates therein the elongated protruding member 29 extending along a side portion of the male connector assembly 3 , the slot 92 being used to slidably guide the connector apparatus position assurance device 8 when the connector position assurance device 8 is slidably inserted into the male connector assembly 3 . [0031] FIG. 3 illustrates the retention clip 7 having the inner finger 36 and the outer finger 38 , both fingers 26 , 28 being flexible. When the retention clip 7 is mounted and locked within the male connector assembly 3 , the protrusions 20 , 22 of the retention clip 7 are accommodated within slots 12 , 14 , respectively, of the male connector assembly 3 , while opposing slots 16 , 18 of the male connector assembly 3 accommodate therein protrusions (not shown) extending from a lower side of the retention clip 7 , the inner protruding member 54 of the lever arm 50 of the male connector assembly 3 being wedged within the space 60 to prevent the flexible outer finger 38 from moving downward for securing the retainer clip 7 within the male connector assembly 3 by ensuring that the protrusions 20 , 22 remain within the slots 12 , 14 , respectively. The end portion of the lower side 32 has a substantially flat raised portion 93 , while the end portion of the outer finger 38 has a sloping portion 95 , the substantially flat raised portion 93 and the sloping portion 95 abutting and contacting the lower substantially flat surface 56 and the substantially inclined surface 55 , respectively, of the inner protruding member 54 of the free end 52 of the lever arm 50 , when the retention clip 7 is mounted and locked within the male connector assembly 3 . [0032] The free end portion of the inner finger 36 has a ledge-like member 95 , while the free end portion of the outer finger 38 has a ledge-like member 98 . [0033] During assembly of the in-line sealed electrical connector apparatus 1 , FIGS. 4-7 illustrate the mating of the female connector assembly 5 , the retention clip 7 , and the connector apparatus position assurance device 8 , with the presumption that the retention clip 7 has been mounted within the male connector assembly 3 . For clarification, in FIGS. 4-7 , the retainer clip 7 is not shown already mounted within the male connector assembly 3 so as to better explain the insertion and locking steps when the female connector assembly 5 , the retention clip 7 , and the connector apparatus position assurance device 8 achieve full mating and in final lock position. That is, to better understand the mating and locking steps of the female connector assembly 5 , the retention clip 7 and the connector apparatus assurance device 8 , the illustration of the male connector assembly 3 has been omitted from FIGS. 4-7 . In this invention, the retention clip 7 has been pre-mounted and locked, in the manner described above, within the male connector assembly 3 before the female connector assembly 5 is inserted into the retention clip 7 and before the connector apparatus position assurance device 8 is inserted into the male connector assembly 3 . [0034] During initial insertion of the connector apparatus position assurance device 8 , in the pre-lock position, as shown in FIG. 4 , the insertion of the female connector assembly 5 into the retention clip 7 raises the outer finger 38 . The raising of the outer finger 38 results in the first leading end member 70 of the connector apparatus position assurance device 8 to be blocked by the end portion of the outer finger 38 . Further, the inner finger 36 remains in its lowered position; consequently, the second leading end member 72 of the connector apparatus position assurance device 8 is blocked by the end portion of the inner finger 36 . Thus, at initial insertion shown in FIG. 4 , the connector apparatus position assurance device 8 remains at a pre-lock position and cannot yet be inserted. [0035] As shown in FIG. 5 , when the female connector assembly 5 is further inserted (but not yet fully inserted) into the retention clip 7 , the leading end portion of the female connector assembly 5 reaches the inner finger 36 and raises the inner finger 36 . Consequently, the second leading end member 72 of the connector apparatus position assurance device 8 becomes unblocked. However, because the outer finger 38 remains in a raised position, the first leading end portion 70 of the connector apparatus position assurance device 8 remains blocked. Thus, the connector apparatus position assurance device 8 remains at a pre-lock position and cannot yet be inserted. [0036] In FIG. 6 , the female connector assembly 5 has been fully inserted into the retention clip 7 . Consequently, the outer finger 38 has dropped into the elongated slot 40 of the female connector assembly 5 , thereby lowering the outer finger 38 . With the lowered outer finger 38 and with the raised inner finger 36 , the first leading end portion 70 and the second leading end portion 72 , respectively, of the connector apparatus position assurance device 8 become unblocked, and the connector apparatus position assurance device 8 is set and ready to be inserted. [0037] With the female connector assembly 5 fully inserted into the retention clip 7 , as shown in FIG. 7 , the outer finger 38 is lowered when it drops into the elongated slot 40 of the female connector assembly 5 and the inner finger 36 remains raised, thereby unblocking the first and second leading end portions 70 , 72 , and allowing the connector apparatus position assurance device 8 to be fully inserted to complete the lock position and be at final lock position. [0038] FIG. 8 shows the in-line sealed electrical connector apparatus of this invention in which the connector apparatus position assurance device 8 is in final lock position, ready to receive a wire assembly (not shown) to be inserted into the openings (not shown) passing through the cover 10 of the male connector assembly 3 and another wire assembly (not shown) to be inserted into the female connector assembly 5 through openings (not shown) at a free end 6 thereof. As shown in FIG. 8 and as discussed earlier, the retention clip 7 is mounted and kept locked within the male connector assembly 3 with the protrusions 20 , 22 of the retention clip 7 being respectively accommodated within the slots 12 , 14 of the male connector assembly 3 . (Protrusions (not shown) extending from the lower side of the retention clip 7 are similarly accommodated within respective slots 16 , 18 (see, FIG. 1 ) of the male connector assembly 3 .) [0039] In order to more clearly illustrate the connector apparatus position assurance device 8 in its fully inserted position and in complete or final lock position, the illustration of the side portion of the male connector assembly 3 containing the lever arm 50 and the bar 62 of the male connector assembly 3 is omitted in FIG. 8 . (Only a cross-section of the inner protruding member 54 of the lever arm 50 , discussed earlier, is shown in FIG. 8 , positioned within the space 60 between the end portions of the lower side 32 and the outer finger 38 of the retention clip 7 .) The connector apparatus position assurance device 8 , with its bottom elongated member 81 being seated on the generally L-shaped member 53 extending from the lower side of the male connector assembly 3 , is prevented from sliding out by the protrusions 79 and further prevented from moving laterally by its base end 75 being seated via the slot 92 thereof onto the elongated protruding member 29 extending along the side portion of the male connector assembly 3 . The first leading end member 70 is seated onto the ledge-like member 98 of the free end portion of the outer finger 38 , while the second leading end member 72 abuts a side portion of the free end portion of the outer finger 38 . The cover 10 is slidably mounted onto the male connector assembly 3 and locked thereto with the upper protrusion 30 and the lower protrusion (not shown) of the male connecter assembly 3 being respectively accommodated within the upper slot 25 and the lower slot 27 of the cover 10 . [0040] As discussed above, the connector apparatus position assurance device 8 of this invention cannot be inserted past the pre-lock position until the female connector assembly 5 has been fully inserted and mated with the male connector assembly 3 . [0041] Also, with the in-line sealed electrical connector apparatus 1 of this invention, if the connector apparatus position assurance device 8 happens to be fully inserted and in the final lock position before the female connector assembly 5 is inserted, the first leading end portion 70 of the connector apparatus position assurance device 8 is positioned on the ledge-like member 98 of the free end portion of the outer finger 38 of the retention clip 7 . Consequently, the outer finger 38 is at a lowered position, and is prevented from being raised by the first leading end portion 70 . Thus, the outer finger 38 blocks the female connector assembly 5 from entering the retention clip 7 . In other words, the female connector assembly 5 will detect its inability to be inserted by the inability of the outer finger 38 to be raised upward, for allowing the female connector assembly 5 to be inserted into the retention clip 7 , when the connector apparatus position assurance device 8 is in the final lock position. [0042] Moreover, the female connector assembly 5 can only fully mate or inserted into the male connector assembly 3 when the connector apparatus position assurance device 8 is in the above-discussed pre-set position. If, for example, a partial or improper mating is achieved (i.e., if the female connector assembly 5 is partially or improperly inserted into the male connector assembly 3 , as shown in FIG. 4 or FIG. 5 ), the connector apparatus position assurance device 8 cannot move forward or inserted because either the inner finger 36 has not been raised for allowing the second leading end member 72 of the retention clip 7 to be unblocked or the outer finger 38 has not been lowered for allowing the first leading end member 70 to be unblocked. Only when the female connector assembly 5 has fully mated or inserted into the male connector assembly 3 has occurred will the connector apparatus position assurance device 8 be allowed to be fully moved forward or inserted because the inner finger 36 has been raised for unblocking the second leading end member 72 of the retention clip 7 and the outer finger 38 has been lowered for unblocking the first leading end member 70 of the retention clip 7 , as shown in FIGS. 6 , 7 and 8 ), thereby having the connector apparatus position assurance device 8 to be in final lock position. [0043] The present invention is not limited to the above-described embodiments; and various modifications in design, structural arrangement or the like may be used without departing from the scope or equivalents of the present invention.

4y

FIELD OF INVENTION This invention relates to devices for facilitating the use of a drill and in particular drill presses which can be attached to a work piece on site. BACKGROUND OF THE INVENTION It should be noted that reference to the prior art herein is not to be taken as an acknowledgement that such prior art constitutes common general knowledge in the art. Drill presses are normally permanently and rigidly mounted on a bench so that the work piece to be drilled has to be taken to the bench. Accordingly they are of no use when the work piece is too large to fit on the bench or it is not convenient to transport it to the bench. For this reason there have been a number of attempts at devising a portable drill press which can be used on site. US 20030143041 teaches a rack bar with a brace attached at one end and a pinion slide assembly engaged with the rack bar such that the pinion is in rotational engagement with the rack. A hand drill is mounted on a bracket attached to the pinion slide assembly and the brace is held or clamped to the work piece. U.S. Pat. No. 2,737,065 teaches a similar device which is also held or clamped to the work piece being drilled while a rack and pinion assembly urge a drill mounted on the pinion towards the work piece. A collar separate from the drill mount is urged by operation of a lever against the upper end of the drill mount to move the drill toward the base. However neither of these prior art devices operate in the manner of a drill press which is permanently mounted on a bench since they have to be held against the work piece by the operator or a separate clamp has to be used. This does not allow for accuracy nor ease of drilling especially when the work piece has to be addressed from below as in the case of roof beams. Clearly it would be advantageous if a portable drill press could be devised that helped to at least ameliorate some of the shortcomings described above. In particular it would be advantageous if a portable drill press could be devised which improves the ease and accuracy of drilling or at least provides a useful alternative to the prior art devices. STATEMENT OF THE INVENTION According to a first aspect, the present invention provides a drill press comprising a hollow pillar with a base, a holder for a drill slidably mounted on the pillar and a clamp with a jaw held by an arm which engages a screw thread shaft housed in the pillar so that rotating the shaft raises and lowers the arm and the jaw, wherein the clamp is used for clamping the base to a work piece so that the drill is guided to the work piece. Preferably, the clamp is an F clamp, a G clamp or a C clamp. Preferably, the drill press may further comprise a pinion rotatable by a lever, the pinion is pivoted in a housing and engages a rack formed on an outer surface of the pillar so that rotating the lever urges the drill vertically towards or away from the work piece. Preferably, the drill press may further comprise a spring located on either side of the arm to restrain movement of the jaw. Alternatively, the spring may be located on one side of the arm to restrain movement of the jaw. Preferably, the arm may have an internal thread which engages the screw thread shaft located within the pillar of the drill press. The arm may protrude through an opening in one side of the pillar, the opening being of sufficient size to allow the arm to move up or down to secure or release the clamp with a jaw to a work piece. Preferably, the opening in the pillar may allow the clamp with a jaw to rotate through an arc located either side of an axis passing vertically through the centre of the pillar. Alternatively, the pillar may further comprise an opening which allows the clamp with a jaw to rotate through an arc of 180 degrees with respect to an axis passing vertically through the centre of the pillar. Preferably, the clamp with a jaw may be withdrawn upwards into the pillar through a slot in the base so that the base can sit flush on a surface. Preferably, the screw thread shaft may be rotated by a handle attached to the top of the shaft which protrudes at the top of the pillar to allow the arm to move up and down to secure the clamp with a jaw to a work piece. Preferably, the pinion and rack may be both located within the housing with the housing being attached to at least one side of the pillar, at least one lever extending externally of the housing to engage and rotate the pinion to move the holder for the drill and therefore the drill vertically towards and away from the work piece. Preferably, the drill may comprise any one of: (1) an electric drill; (ii) a pneumatic drill; (iii) a hydraulic drill or (iv) an electromagnetic drill. The electromagnetic drill may be either mounted using the electromagnet to the base of the drill press or the electromagnetic drill may be mounted to the housing attached to at least one side of the pillar. Preferably, the drill press may comprise: at least two hollow pillars mounted on a base; at least two holders slidably mounted on the pillars, at least one holder containing a drill; at least two clamps each with a jaw held by an arm which engage a screw thread shaft housed in each of the pillars so that rotating the shaft raises and lowers the arm and the jaw independently within each pillar; and wherein each clamp is used for clamping the base to a work piece. The other holder mounted on the pillar may contain any one of: (i) a drill; or (ii) a drop saw. Preferably, the base may be adapted to hold any one or combination of: (i) a vise; (ii) a tool box; (iii) temporary lighting; (iv) a television; or (v) a work bench. Preferably, the base of the drill press may further include an opening in the base which allows the drill to pass through the opening and drill into the work piece clamped to the base of the drill press. Preferably, to compress the spring and to allow the clamp with a jaw to move in and out relative to the base of the drill press, plates may be provided protruding and extending from either side of the arm a distance which is sufficient to allow the fingers of the user's hand to be comfortably placed under the plates, and with the user's thumb placed on a top end of the clamp with a jaw to compress the spring. Preferably, a further clamp may be added to secure the drill press to a work piece, wherein the clamp is either a G clamp or an F clamp. Preferably, the jaw of the clamp may further comprise brackets mounted to an end of the jaw to facilitate the attachment of the jaw of the clamp to a pipe or cylindrical work piece. The base of the drill press may comprise brackets attached to the underside of the base to facilitate the clamping of the base to a pipe or cylindrical work piece. Preferably, the at least two pillars and clamps may further comprise a bridge or saddle located between and joining the at least two pillars and clamps. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a perspective view of a portable drill press incorporating a clamp in accordance with an embodiment of the present invention; FIG. 2 shows a side elevation of the press of FIG. 1 with sections cut-away to expose the operation of the press; FIG. 3 shows a view of FIG. 2 with the clamp withdrawn upwards for a flush mount operation; FIG. 4 shows a rear perspective view of the clamp in accordance with an embodiment of the present invention; FIG. 5 illustrates a view of the press of FIG. 1 clamped beneath a roof beam in accordance with an embodiment of the present invention; FIG. 6 illustrates a view of the press of FIG. 1 clamped on the rear of a truck deck in accordance with an embodiment of the present invention; FIG. 7 shows a side view of the clamp in accordance with a further embodiment of the present invention; FIG. 8 shows the clamp of FIG. 7 in use clamped to a wide beam; FIG. 9 shows the clamp of FIG. 7 in use clamped to a narrow beam; FIG. 10 shows the manual operation of the clamp and clamp spring of FIG. 7 with the spring compressed to open the clamp; FIG. 11 shows the manual operation of the clamp and clamp spring of FIG. 7 with the spring fully compressed; FIG. 12 shows the clamp of FIG. 7 attached to a narrow beam with the drill press removed for clarity and a clamping vice attached to the base; FIG. 13 shows the clamp of FIG. 7 attached to a wide beam with the drill press removed for clarity and a tool box mounted to the base; FIG. 14 shows the clamp of FIG. 7 attached to a vertical post with the drill press removed for clarity and a light mounted to the base; FIG. 15 shows the clamp of FIG. 7 attached to a roof beam with the drill press removed for clarity and a television mounted to the base; FIG. 16 shows a further embodiment of the clamp which has been adapted to clamp to a pipe in accordance with the present invention; FIG. 17 shows a further embodiment of the portable drill press incorporating the clamp of FIG. 7 in accordance with the present invention; FIG. 18 shows a side view of portable drill press with a clamp in accordance with a further embodiment of the present invention; FIG. 19 shows a top view of the portable drill press of FIG. 18 ; FIG. 20 shows a further embodiment of the present invention in which two clamps have been modified to attach the portable drill press to a pipe; FIG. 21 shows a further embodiment of the present invention in which two clamps with the drill press removed for clarity, the clamps modified to attach to pipes or rails; and FIG. 22 shows a further embodiment of the present invention in which two clamps have been modified for attachment to a pipe with one clamp having a portable drill press (removed for clarity) and the other clamp having a drop saw attached. DETAILED DESCRIPTION OF THE INVENTION In the drill press shown in FIG. 1 , hand drill 1 is securely mounted by bracket 2 to housing 3 which is in sliding engagement with pillar 4 made from a hollow rectangular tube. Pillar 4 has rack 5 formed in its outer surface facing drill 1 and mating pinion 6 is pivoted in housing 3 and rotatable by lever 7 . A drill press (also known as a pedestal drill, pillar drill, or bench drill) is a fixed style of drill that may be mounted on a stand or bolted to the floor or workbench. Portable models with a magnetic base grip the steel work pieces they drill. A drill press consists of a base 8 , column (or pillar) 4 , and drill 1 with a drill head and chuck. The drill 1 is typically driven by an induction motor. The drill press has a handle 7 or a set of handles (usually 3) radiating from the housing or central hub 3 that, when turned, move the drill 1 and chuck vertically, parallel to the axis of the pillar 4 . As stated above the pillar 4 has a rack 5 and the mating pinion 6 is located in the housing 3 which in conjunction with the handle 7 move the drill and chuck vertically. A rack 5 and pinion 6 is a type of linear actuator that comprises a pair of gears which convert rotational motion into linear motion. A circular gear or the pinion 6 engages teeth on a linear gear bar or rack 5 . Rotational motion applied to the pinion 6 causes the housing 3 to move, thereby translating the rotational motion of the pinion 6 into the linear motion of the housing 3 . The size of a drill press is typically measured in terms of swing. Swing is defined as twice the throat distance, which is the distance from the center of the spindle to the closest edge of the pillar 4 . The hand drill or simply drill 1 is a tool fitted with a cutting tool attachment or driving tool attachment, usually a drill bit or driver bit, used for drilling holes in various materials. The attachment is gripped by a chuck at one end of the drill 1 and rotated while being pressed against the material to be drilled. There are many types of powered drills 1 some are powered using electricity (electric drill), compressed air (pneumatic drill) or a compressed liquid (hydraulic drill) as the motive power. Another type of powered drill is the electromagnetic drill press which uses an electromagnet in the base that allows the drill 1 to attach directly to any metal surface which can be magnetised. The electromagnetic drill 100 is only useful if the work piece to be drilled is able to be easily magnetized. For example metals which are ferrous metals such as iron, nickel, cobalt and certain steels are easily magnetised. Whereas, materials such as brass, aluminum, copper, and most stainless steels are not easily magnetised and are therefore called non-ferrous materials. Therefore the electromagnetic drill 1 is generally used for construction with ferrous metals such as steel. The high-powered magnet in the base clamps the drill 1 tightly to steel preventing the drill from moving. FIGS. 1 to 4 show the pillar 4 is held vertically on base 8 and extends upward and perpendicular to the base 8 . The pillar 4 houses a threaded shaft 9 held loosely by top closure 10 and bottom spacer 11 and retained on spacer 11 by stop 12 as revealed in FIG. 2 . The internal end of clamp arm 13 has an internal thread which engages the thread of the shaft 9 through cut out 14 in pillar 4 and moves up and down as handle 15 rotates shaft 9 . The external end of arm 13 receives clamp jaw 16 which is slidably restrained on arm 13 by locating spring 17 . The locating spring 17 is located on either side of the arm 13 to restrain movement of the clamp jaw 16 . As will be described in more detail below the spring 17 can be placed in a number of different positions to physically restrain the movement of the clamp jaw 16 . Accordingly base 8 can be secured to a work piece (shown in dotted outline) by rotating the handle 15 which in turn rotates the threaded shaft 9 and moves the arm 13 upward so that jaw 16 grips the work piece. Likewise the base can be released from the work piece by rotating the handle 15 in the opposite direction which rotates the threaded shaft 9 in the opposite direction therefore moving the arm 13 away from the work piece. With the base 8 secured to the work piece the drill 1 can then be urged down on the work piece by rotating lever 7 anticlockwise which moves the drill 1 vertically downward, parallel to the axis of the pillar 4 . The drill 1 can then drill the desired hole through cut out 18 (as shown in FIG. 1 ) in base 8 . When completed the drill 1 is withdrawn from the work piece by rotating lever 7 in a clockwise direction which moves the drill 1 vertically upwards away from the work piece. In this embodiment an F clamp is used to secure the work piece to the base 8 . An F-clamp, also known as a speed clamp is a type of clamp which takes its name from its “F” shape. The F-clamp is similar to a C-clamp in use, but has a wider opening capacity (throat). Alternatively in other embodiments a G clamp is used to secure the work piece to the base 8 . FIG. 3 shows the drill press with jaw 16 withdrawn upwards into pillar 4 so that base 8 can sit unobstructed on the top surface of the work piece 19 . In this configuration G clamp 24 is further used to secure base 8 to the top surface of work piece 19 . FIG. 4 is a rear perspective view showing clamp arm 13 and jaw 16 . In normal use the arm 13 is clamped in line with the pillar 4 to a bench or to a job. Due to the cutout 14 in the pillar 4 the arm 13 is able to rotate through an arc as shown by the arrows. This allows the clamp jaw 16 to be rotated a certain distance away from either side of the centre of the pillar 4 . This further provides the advantage of being able to move the jaw 16 into a number of positions which is advantageous in some drilling operations when space is limited. As will be discussed below in more detail the cutout 14 may also extend to the sides of the pillar 4 adjacent the cutout 14 so that the jaw 16 may be rotated through 180 degrees with respect to the pillar 4 . In FIG. 5 the drill press is shown clamped to roof beam 20 from its underside allowing the operator to use the drill simply by rotating lever or handle 7 . By rotating the handle 7 the drill 1 is moved vertically towards the roof beam 20 and a hole is drilled through the cut out 18 into the roof beam 20 while the drill press is securely suspended from the bottom of the roof beam 20 . In FIG. 6 the drill press is clamped to the rear of truck deck 22 and G clamp 23 is used to secure work piece 21 to deck 22 . It will be apparent that the drill press of the present invention allows both clamped and unclamped operation and facilitates drilling in a wide variety of situations. FIG. 7 illustrates a side view of a further embodiment of the clamp 30 with the drill press removed for further clarity. To facilitate the description of this embodiment like numbered components used in the earlier embodiment are given the same reference numerals in this embodiment. The clamp 30 includes the pillar 4 held vertically on base 8 and extending upward and perpendicular to the base 8 . The pillar 4 houses a threaded shaft 9 held loosely by top closure 10 and bottom spacer 11 and retained on spacer 11 by stop 12 . The internal end of clamp arm 13 has an internal thread which engages the thread of the shaft 9 . As handle 15 is rotated threaded shaft 9 moves the clamp arm 13 up and down. The external end of arm 13 receives clamp jaw 16 which is slidably restrained on arm 13 by locating spring 17 . The spring 17 is restrained between the top side of the arm 13 and a cap 32 which is secured to the clamp jaw 16 by pin 31 . The spring 17 is a compression spring which offers resistance to compressive forces which, when the spring is compressed it exerts a force which is proportional to its change in length. FIG. 8 shows the clamp 30 used to clamp the base 8 of the drill press to a post 32 . As this item is of significant width the spring 17 is compressed more than previously shown in FIG. 7 to allow the clamp jaw 16 to extend in the direction of the arrow and around the post 32 . Likewise and as shown in FIG. 9 an item of less width in which the clamp jaw 16 moves in the direction of the arrow and the spring 17 is compressed less than as shown in FIG. 8 . FIG. 10 shows by way of example the manual operation of the spring and the clamp jaw 16 . As the spring is manually compressed and released by the fingers of the user hand 40 and as shown by arrow A, the spring will allow the clamp jaw 16 to move in the corresponding direction as indicated by arrow B. As the spring is compressed the arrows A comes closer together and likewise the clamp jaw 16 moves further away from the base 8 therefore the arrows B move further apart. In order to facilitate the compression of the spring 17 and to allow the clamp jaw 16 to move in and out relative to the base 8 of the drill press, plates 34 extending from either side of the arm 13 are provided. The plates 34 extend away from the arm 13 a distance which is sufficient to allow the fingers of the user's hand 40 to be comfortably placed under the plates 34 . With the user's thumb placed on a top end of the clamp jaw 16 above the cap 30 , the spring 17 is compressed as shown in FIG. 11 . FIGS. 12 to 16 show further arrangements and uses of the present invention. In these figures the drill press has been removed for clarity to show these further uses of the clamp 30 . In FIG. 12 the base 8 of the drill press is used as a work bench with a vise 50 attached to the base 8 . The clamp 30 is attached and secured to a beam 33 . FIG. 13 shows a tool box 60 held in a frame 61 which is attached to the base 8 . The clamp 30 is attached and secured to a post 32 . Other uses of the drill press and clamp 30 are illustrated in FIGS. 14 and 15 . In FIG. 14 a temporary flood light is attached to the base 8 of the drill press and the clamp 30 is securely attached to the vertical pole 71 . In FIG. 15 a flat screen television 80 is attached to the base 8 and the clamp 30 is secured to the roof rafter or beam 81 . FIG. 16 illustrates the drill press and modified clamp 30 attached to a pipe system 90 as would be seem in a refinery, pipe line or industrial plant. In this embodiment the base 8 of the drill press is used as a work bench with a cleaning tray 91 placed on top of the base 8 . The clamp jaw 16 has been modified to include pipe clamp brackets 92 , with the same brackets 92 attached to the underside of the base 8 . This allows the clamp 30 to securely attach to any pipe shaped fitting or hollow cylindrical pipe. FIG. 17 illustrates a further embodiment of the present invention with the clamp 30 used with an electromagnetic drill 100 with the electromagnet removed from the drill base and the electromagnetic drill 100 attached to the pillar 4 . This allows for the powerful electromagnetic drill to be used in situations where there is little or no metal which can be magnetised. The pillar 4 is held vertically on base 8 and extends upward and perpendicular to the base 8 . The pillar 4 houses a threaded shaft 9 and the internal end of clamp arm 13 has an internal thread which engages the thread of the shaft 9 in pillar 4 and moves up and down as handle 15 rotates shaft 9 . The external end of arm 13 receives clamp jaw 16 which is slidably restrained on arm 13 by locating spring 17 . The clamp jaw 16 is extended to attach to pillar 33 to secure the drill press to the item to be drilled. The drill press has a set of handles (usually 3) 101 radiating from the housing or central hub 97 that, when turned, move the drill 100 and chuck vertically, parallel to the axis of the pillar 4 . Located within housing 97 is a rack and a mating pinion which in conjunction with the handle 101 move the drill and chuck vertically. The housing 97 is secured to the pillar 4 via plate 95 and threaded bolts 96 . The plate 95 extends from one side of the pillar 4 and the threaded bolts 96 pass through holes in the plate 95 and are secured in threaded sockets located on the rear side of the housing 97 . FIGS. 18 and 19 show a further embodiment in which the drill press and the electromagnetic drill 100 has the electromagnet 102 attached to the drill 100 . The electromagnet 102 secures the drill 100 to base 8 . The clamp of the present embodiment includes an open section 104 in the pillar 4 which as shown in FIG. 19 allows the clamp to be rotated 180 degrees around the axis extending upward through the centre of the pillar 4 . The clamp is secured to a work piece 103 by clamp jaw 16 as has previously been described. FIG. 20 illustrates a further embodiment of the present invention in which two clamps 30 are used to secure the drill press and drill 100 to a pipe 90 . This embodiment is particularly useful when the pipe is an alloy pipe, stainless steel pipe or poly or plastic pipe or fibrous pipe. In this situation these pipes cannot be magnetised and therefore you would not be able to use the standard electromagnetic drill to easily drill into these pipes. The base of the drill press includes pipe clamp brackets which extend along the underside of the base 8 to assist in securing the drill press to the pipe 90 . The clamp jaw 16 is also modified to allow for pipe clamp brackets on the end of the clamp jaw 16 to secure to the underside of the pipe 90 . The operation of the two clamps 30 is identical to that described above for one clamp 30 . FIG. 21 illustrates a further use of the drill press and clamps 105 with the drill press removed for clarity. In this embodiment two modified clamps 105 are used to secure the drill press to a pipe 90 which is to be welded. The two clamps 105 are secured to the pipe 90 by clamp jaw 106 which has a cylindrical end. The two clamps 105 are joined and held together by saddle 107 which ensures that when the pipe is welded by a welder 110 and user 120 the joint to be welded is kept perfectly aligned and square so that the weld formed is parallel with either end of the pipe 90 therefore forming a perfect welded Joint. This type of embodiment is perfect for welding hand rails and large diameter pipes where a clean and perfect weld is required. FIG. 22 illustrates a further use of the two clamps 30 in the same configuration as described in FIG. 20 . In this embodiment a drop saw 130 is attached to a base 131 at one side and beside one of the clamps 30 and on the other side next to the other clamp 30 is a drill press (removed for clarity). In this embodiment not only can the clamps 30 be used for a drill press but they can also be used to cut items to length without the user having to move to another work bench to complete a job. Both drilling and cutting can be carried out at the same work station or in whatever positions the clamps 30 are attached as previously described in other embodiments of the present invention. In this example the drill press and drop saw 130 are attached to a remote pipe line 90 . The component parts of the drill presses of the above embodiments can be constructed from any light-weight metal or non-metal materials. The only component which has to be constructed from steel is the base 8 . In order for the electromagnetic drill 100 to be able to be secured to the base 8 by the electromagnet the base 8 must be a ferrous magnetic material such as steel. By keeping the remaining components of the drill press to light-weight metals or non-metals achieves a drill press which is significantly lighter and portable than most other drill presses. ADVANTAGES The present invention provides a number of important advantages over the prior art. Firstly the present invention is considerably lighter in construction than the prior art which is particularly important when the user is working on a roof structure and attempting to drill holes in roof rafters or beams. The drill press must be versatile and light-weight in order for the user to work in places where the work piece cannot be taken to the drill press. Another advantage with the present invention is that no power is required in order for the drill press to be secured to the work piece. In use an electromagnetic drill requires a power supply to electrically magnetise the base so that the electromagnetic drill can be secured to the workpiece. When working at heights or a distance from a power source, leads must be used to connect the power to the electromagnetic drill. At a work site there is regularly a number of workers on site at any one time, therefore there is always a danger that a power supply can be disconnected and therefore the electromagnetic drill can have power removed inadvertently and this poses a great risk to users. The present invention uses a mechanical clamp to easily secure the drill press to the work piece therefore is much safer and avoids any serious injuries to users and avoid any occupational health and safety issues. VARIATIONS It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. Throughout the description and claims to this specification the word “comprise” and variation of that word such as “comprises” and “comprising” are not intended to exclude other additives components integers or steps.

4y

This is a division of application Ser. No. 07/423,181, filed Oct. 18, 1989, which issued Nov. 12, 1991, as U.S. Pat. No. 5,064,766. BACKGROUND OF THE INVENTION The present invention relates to testing for occult gastrointestinal bleeding. The common screening test for occult gastrointestinal bleeding is the test for fecal occult blood (FOB). This test involves placing a sample of stool onto a testing surface and adding one or more reagents which react with the blood in the sample to produce a recognizable color. Two current varieties of such tests are the Hemoccult® device and the HemaWipe® device. The Hemoccult® test device requires that one use a small paddle to fish a feces sample out of the toilet and apply the sample to a piece of test paper mounted on a card. U.S. Pat. No. 3,996,006 to Pagano is exemplary of a Hemoccult® test device. The HemaWipe® device utilizes a test pad adhered to a pliant impermeable base sheet and covered with a pliant volume control sheet having openings therein in alignment with the test pad. The patient can wipe with the HemaWipe® device, remove the volume control cover sheet, fold the pliant base sheet over on itself to seal the test pad and sample and submit it for testing. A number of prior patents relate to the HemaWipe® device including U.S. Pat. No. 4,808,379, entitled "DEVICE FOR OBTAINING STOOL SAMPLES," issued Feb. 18, 1989, U.S. Pat. No. 4,804,518, entitled "DEVICE FOR OCCULT BLOOD TESTING," issued Feb. 14, 1989, U.S. Pat. No. 4,559,949, entitled "STOOL SAMPLING DEVICE," issued Dec. 24, 1985, U.S. Pat. No. 4,420,353, entitled "METHOD OF MAKING A STOOL SAMPLING DEVICE," filed Dec. 13, 1983, U.S. Pat. No. 4,367,750, entitled "DEVICE FOR OBTAINING STOOL SAMPLES," issued Jan. 11, 1983, U.S. Pat. No. 4,273,741, entitled "DEVICE FOR OBTAINING STOOL SAMPLES," issued Jun. 16, 1981, and U.S. Pat. No. 4,259,964, entitled "DEVICE FOR OBTAINING STOOL SAMPLES," issued Apr. 7, 1981. Virtually all FOB tests used today have the problem of nonspecificity. Their chemical reactions detect the peroxidase property of hemoglobin by causing the catalysis of peroxide into oxygen and water, and the subsequent oxidation of a colorless dye into a colored form. Gum guaiac is the most commonly used color reagent, although a large number of other reagents have been used in the past. The nonspecificity is due to two reasons. First, there are other peroxidase positive materials which the patient may eat, which, when excreted, will also cause a positive reaction. Secondly, there is a normal, small loss of blood into the GI tract which in some patients will escape into the stool in amounts large enough to cause a reaction. It is obvious that the more sensitive the reagent, the more sensitive the test, but the more likely that there will be a false-positive reaction. The FOB tests are more frequently used to screen patients for a hidden colonic malignancy, so that the consequences of missing any bleeding can be severe. Conversely, if there are a large number of false-positive tests, the expense and possible complications of the additional follow-up tests involved are also considerable. There have been many attempts to make the FOB test more specific, and thus allow adequate sensitivity while preventing the undesired false-positive results. Specific immunologic tests have been employed which are sensitive only to human blood. The problem with these have been that they are much more complicated and expensive than the usual screening test, and the blood may be altered by partial digestion so that it is not detected by immunologic means. A recent technique called Hemaquant involves the extraction of a stool sample to obtain porphyrins, the breakdown products of blood. The advantage of this technique is that it is quantitative and relatively specific, but it too is expensive and much more cumbersome than the usual screening tests. An important consideration in any work-up for GI bleeding is the source. Where the FOB test is used to screen for colo-rectal cancer, the only blood of interest is from the lower GI tract. Blood from gastritis or dental bleeding would be considered a false-positive, even though blood was indeed present. It can therefore be seen that the concept of a false-positive test involves more than the incorrect detection of blood but also the circumstances under which it is detected. Ideally, an FOB test would not only reliably detect blood but also give some indication as to the origin of the blood. It is therefore an object of this invention to provide a simple but accurate means of detecting a small amount of blood in a sample of stool. It is also a object of this invention to provide an indication of the origin of the blood. SUMMARY OF THE INVENTION The present invention is based on the fact that blood, as it passes through the GI tract, changes character in ways that allow the blood from various sites to be physically separated and detected. When blood (either from the patient or ingested) passes through the normal stomach, hydrochloric acid converts the relatively uncharged hemoglobin to hematin and related hemoglobin breakdown products (HBPs), which are highly charged. In the present invention, a fecal sample is placed on a charged absorbant medium which will absorb hematin and/or other hemoglobin breakdown products and hemoglobin The medium is charged to be differentially attractive to hematin and hemoglobin breakdown products on the one hand and hemoglobin on the other. A solvent for hematin and/or other hemoglobin breakdown products and hemoglobin is then placed on the charged medium and allowed to migrate through the medium and through any material absorbed from the fecal sample to extract a detectable amount of hemoglobin and hematin and/or other hemoglobin breakdown products from the sample and to migrate through said medium. The hematin and any hemoglobin breakdown products tend to migrate more slowly than the hemoglobin due to the charge on the medium. Means for indicating hematin and/or other hemoglobin breakdown products and hemoglobin are then used to cause their visual detection. The most obvious advantage of the foregoing invention is that it allows the doctor to determine whether fecal occult blood is originating in the upper GI or in the lower GI. If the blood is originating in the lower GI, further testing is called for. If it is originating in the upper GI, treatment for ulcers and/or dietary changes will be prescribed. A follow up fecal occult blood test performed several weeks later will indicate whether the treatment has been successful and if not, further tests can be conducted. Also of interest, however, is that animal and vegetable peroxidases which constitute the usual dietary false-positives are also charged, like hematin and other hemoglobin breakdown products. Hence, these false-positive peroxidases also tend to "stick" to and are prevented from migrating through the medium. Because of this, the test of the present invention can be made more sensitive by increasing the indicator dye concentration. In the prior art, the indicator dye is kept at a lesser concentration to avoid showing too many "false-positives" which result from dietary blood or dietary peroxidases. As a result, a substantial portion of fecal occult blood tests which are performed fail to show the presence of fecal occult blood originating in cancerous tumors in the lower intestine. By using the present invention, it is believed one can increase the concentration of indicator dye without encountering false-positives, and thereby greatly increase the sensitivity of the test to the presence of hemoglobin resulting from cancerous formations in the lower intestine. These and other objects, advantages and features of the invention will be more fully understood and appreciated by reference to the written specification and appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a fecal occult blood testing device made in accordance with the present invention; FIG. 2 is a perspective view thereof after a fecal sample has been applied to the volume control top sheet thereof; FIG. 3 is a perspective view of the device with the volume control sheet being removed and with solvent being applied to the absorbant medium; FIG. 4 is a perspective view of the device after an indicator has been applied, showing the differential manner in which hematin and/or other hemoglobin breakdown products and hemoglobin migrate through the absorbant medium; FIG. 5 is a perspective view of an alternative embodiment of the invention; FIG. 6 is a cross-sectional view taken along plane VI--VI of FIG. 5; FIG. 7 is a perspective view of another alternative embodiment of the invention; FIG. 8 is a cross-sectional view of another alternative embodiment with the base sheet being partially broken away; FIG. 9 is a top plan view of the test medium portion of the alternative embodiment as it will look when tested positive for fecal occult blood originating in the lower intestine; FIG. 10 is a cross-sectional view of the test pad portion of the alternative embodiment as it will appear when tested positive for fecal occult blood originating in the lower intestine; FIG. 11 is a top plan view of the test pad portion of the alternative embodiment device as it appears when tested positive for fecal occult blood originating in the upper intestine only; and FIG. 12 ia a cross-sectional view thereof. DESCRIPTION OF THE PREFERRED EMBODIMENT In a preferred embodiment, the fecal occult blood testing device 1 for use in the present invention comprises a base sheet 10 to which is secured a charged, absorbant test medium 20 (FIG. 1). A test sample volume control cover sheet 30 overlies test medium 20 and includes a plurality of openings 31 therein A portion of fecal material wiped onto volume control cover sheet 30 (FIG. 2) passes through openings 31 onto test sheet 20, and the remaining portion of the sample is removed by removing cover sheet 30 (FIG. 3) and disposing of it. Base sheet 10 is preferably made of a pliable, water-resistant material. By making base sheet 10 pliable, device 1 can be used as a wipe rather than as a receptor upon which a fecal sample is smeared using a small paddle. Of course, in the broader aspects of the invention, the use of a small paddle to smear a sample of fecal material onto device 1 is contemplated. A suitable pliable, water-resistant base sheet is a 3.5 mil (0.0035 inch) thick sheet of vinyl plastic material. Test medium 20 comprises a sheet of filter paper impregnated with a suspension of charged material such as silica. Since hematin is negatively charged, the silica must be positively charged, which it is at a pH of around 6.4. The key requirement for test medium 20 is that it allow retention of a stool sample, allow the passage of solvent and can be made to carry a charge materially different from either hematin or hemoglobin. Test medium 20 is adhered to base sheet 10 by a suitable adhesive such as an emulsion base acrylic pressure sensitive adhesive. The specific grade of filter paper is not particularly critical. Medium grade filter paper such as Watman No. 1 is operable. Numerous silicas are available to those skilled in the chromatography arts, many of which are applicable in the present invention. Aerosil™ 200N is operable. The only requirement for the charged particle material is that it be differentially attractive to hematin and hemoglobin such that separation can be effected. The silica particles are approximately two hundred nanometers in diameter. They comprise a very fine, light powder which is fairly widely used. Suitable impregnation can be achieved by forming a thin paste of silica in a 70% ethanol and water carrier. This slurry is then pressed into the filter paper with a roller and the paper is allowed to dry. While impregnating filter paper with silica as described above constitutes the best mode presently contemplated for the invention, it is possible that charged medium can be created by other techniques, as for example treating filter paper with charged organic molecules such as stearates. Another possibility which has not been specifically tested would be to place filter paper in a sulfuric/nitric acid mixture in order to create nitrocellulose paper. Volume control cover sheet 30 controls the quantity of fecal material which is actually applied to test medium 20. It is a sheet of thin, water-resistant material. A suitable material is a silicone coated tissue paper, at a thickness of about 2 mils. The holes or openings 31 are approximately 0.05 to 0.10 inch in diameter and eight to sixteen such openings are arranged in a pattern in one-half of cover sheet 30. Cover sheet 30 is preferably releasably adhered to test medium 20 along end edge 32 so that it can readily be lifted at end edge 33 and peeled away from test sheet 20 and deposited in the toilet. Openings 31 are preferably arranged in a circle. The solvent used to facilitate migration can be placed in the approximate center of the circle defined by openings 31 and will tend to flow radially outwardly. The migration of hematin and hemoglobin will thus be in a consistent, radial pattern with respect to the circle of apertures 31. The solvent 50 must be one which will dissolve hematin and hemoglobin in order the cause them to migrate through the test medium 20. In the preferred embodiment, solvent 50 must also dissolve a buffering agent which helps to ensure an appropriate pH for optimum interaction between the test medium and the hematin. The pH is preferably from about six to about seven, most preferably about 6.4. Sodium acetate is a suitable buffer for this purpose. Water is a good solvent for hematin and hemoglobin, as well as for the buffer. On the other hand, the solvent preferably includes ethanol, which facilitates the characteristic color change reaction of indicators such as guaiac. The solvent preferably includes between about 60 and about 80% by volume ethanol to facilitate the guaiac or other oxygen colored dye color indication reaction while leaving enough water in the solvent mixture to dissolve the acetate buffer and to facilitate the migration of hematin and hemoglobin. The acetate buffer included in the solution is at a level of about 0.05 Normal. The means for indicating the presence of hematin and hemoglobin comprise an oxygen colored dye and a peroxide developer which releases oxygen upon exposure to hematin and hemoglobin. The oxygen colored indicator dye reagent can be gum guaiac, orthodianisidine, tetramethylbenzidine, or the like, with guaiac being preferred. The concentration of oxygen colored dye, most preferably guaiac, is from about 5 to about 25 mg./ml., most preferably about 7 mg./ml. The guaiac should not be so concentrated that it either makes the test too sensitive or obscure the peroxidase reaction. If the test is too sensitive, it will detect the minor amounts of blood normally found in the stool. The preferred solvent used is ethanol. The peroxide solution is preferably about a 1% peroxide solution. The peroxide developer and the indicator dye can be combined in a single solution provided a peroxide stabilizer such as EDTA (ethylene diamine tetraacetic acid) is also included in the solution. In use, device 1 is preferably used as a wipe in such a way that fecal material is wiped onto volume control cover sheet 30. A portion of the fecal material engages test sheet 20 through volume control openings 31. Cover sheet 30 is lifted from end 33, peeled off at end 32 and disposed of. Solvent is then applied by dropper 51 approximately, to the center of the circle defined by dots of fecal material 40 on test sheet 20 (FIG. 3). Four drops or about 0.2 ml. of solvent is normally sufficient. As the solvent migrates outwardly through the test medium, it causes hematin 41 and hemoglobin 42 to migrate differently, due to the attractive charges between hematin and the charged test medium 20. About 30 seconds to one minute are allowed for solvent migration. After the solvent has radiated outwardly approximately the distance indicated in FIG. 4, the indicator reagent containing hydrogen peroxide and guaiac or other color indicator is applied to test medium 20. The guaiac colors do indicate the location of hematin 41 and hemoglobin 42 in the manner indicated. Stool samples which contain only blood from the upper gastrointestinal tract will show color only in close proximity to the test sample dots 40. Thus, in the lower portion of FIG. 4, a showing for hematin 41 only is indicated in close proximity to the adjacent dot of fecal material 40a. On the other hand, stool samples containing blood only from the lower gastrcintestinal tract will tend to form an area 42 extending away from dot 40b of fecal material as indicated in the center of FIG. 4. If the fecal sample contains blood originating in both the upper and the lower gastrointestinal tracts, a mixed pattern will be seen as indicated with the hematin ring 41 and hemoglobin patch 42 radiating away from fecal dot 40c. The alternative embodiment device 100 (FIG. 5) makes it possible to incorporate a hydrogen peroxide "developer" directly into the solvent system. Alternative embodiment 100 includes a base sheet 110 which is just like base sheet 10. However, sheet 120 differs from test medium sheet 20 in that sheet 120 is a piece of plain, absorbant filter paper. It is not treated with charged particles such as the silica discussed above. It is, however, impregnated with guaiac or other indicator dye. A large test dot 121 which is also made of filter paper is impregnated with a suspension of silica in the manner described above. It is adhered to sheet 120 by means of a solvent impermeable adhesive layer 123 (FIG. 6). A fecal sample is applied to test dot 121 through the use of a volume control sheet 130 having openings 131 identical to openings 31, which fall within the circumference of test dot 121 (FIG. 5). The solvent 150 used in connection with alternative embodiment device 100 contains not only acetate buffer as discussed above, but also 1% hydrogen peroxide. The solvent solution is thus a solvent/developer, whereas in the first embodiment, the migration solvent 50 contains a buffer, but no peroxide. FIG. 7 discloses yet another alternative embodiment device 200 which comprises a base sheet 210, an absorbant test medium pad 220 and a volume control cover sheet 230 (FIG. 7). Alternative embodiment 200 is designed so that a patient can use the device at home to collect a feces specimen, seal device 200 and bring it or mail it to the doctor or laboratory. To accomplish the foregoing, pliant base sheet 210 is coated with a pressure sensitive acrylic adhesive as described above, over its entire surface. A fold line 211 is provided laterally across base sheet 210, approximately in the center thereof, by scoring base sheet 210 along fold line 211. A strip of silicone coated release paper 212 is adhered along one end edge of base sheet 210 so that a user can readily grasp the cover sheet 230 along its leading edge 232 when one wants to peel cover sheet 230 off of base sheet 210. Test medium pad 220 is adhered to the surface of base sheet 210 via the pressure sensitive adhesive. Test pad 220 is located on that half of base sheet 210 which is opposite the end where release liner tab 212 is located. On that half of base sheet 210 located toward release liner tab 212, base sheet 210 is cut at spaced intervals along parallel lines 213 to define a test door 214. Test door 214 includes a fold line 215 scored in base sheet 210 at the base of door 214. A tab of silicone release paper 216 is placed along the end of door 214 opposite fold line 215 and a matching strip of silicone release paper 217 is located along the same edge of base sheet 210, adjacent test pad 220. In that manner, when base sheet 210 is folded shut along fold line 211, silicone release liner tabs 216 and 217 will line up and will make it possible to slip one's finger or thumb under the end of test door 214 and peel it back away from base sheet 210. Another sheet of silicone release liner 218 is placed on the surface of test door 214 which lines up with test medium pad 220 so that the adhesive on the surface of test door 214 does not peel any portion of test pad 220 away when door 214 is opened. Test pad 220 can be made exactly like test pad 20 or exactly like test pad 120. In the former case, test pad 220 would be impregnated with silica so as to comprise a charged medium over its entire surface area. In the latter case, test pad 220 would be uncharged, but would include a test dot such as dot 121 in alternative embodiment 100 which would be charged and which would be in alignment with the volume control openings 231 in volume control cover sheet 230. In use, volume control cover sheet 230 would initially be flat against base sheet 210, covering test door 214 and test pad 220. The patient would wipe with device 200 so that fecal material would pass through volume control openings 231 onto test pad 220. Cover sheet 230 would then be peeled away from base sheet 210 and disposed of. The user would then fold base sheet 210 in half along fold line 211, pressing the two halves against one another so that the pressure sensitive adhesive on the surface of base sheet 210 would seal base sheet 210 closed around the perimeter of test pad 220 containing the dots of fecal material. The test pad so sealed can then be mailed in an envelope to a laboratory or doctor. The test for fecal occult blood would be conducted in either of the manners described above, depending on whether one used a charged test pad such as test pad 20, or an uncharged test pad with a charged dot such as test pad 120 and dot 121. The material of base sheet 210 and volume control cover sheet 230 are the same as described above. FIG. 8 shows an alternative embodiment test pad 320 mounted on base sheet 210 of the alternative embodiment device 200 shown in FIG. 7. It is contemplated that this combination will be the best mode for practicing the invention. Test pad 320 comprises an absorbant sheet of paper 320a which is generally rectangular in configuration (FIGS. 9 and 11). Sheet 320a is impregnated with guaiac indicator dye, also described above. Superimposed over absorbant filter paper 320a is a second rectangular sheet of filter paper 321 which is the same width as sheet 320a, but which is slightly shorter in length such that sheet 320a has an exposed upper surface at each end of sheet 321. Sheet 321 is separated from sheet 320a by a solvent impermeable barrier layer 323 which, like sheets 320a and 321 is generally rectangular in configuration, and is of the same width as sheets 320a and 321. However, solvent impermeable barrier layer 323 is slightly shorter than sheet 321 such that a portion of sheet 321 makes direct contact with sheet 320a at each of the opposed ends of sheet 321. Sheet 321 is itself divided into two halves, half 321a which is impregnated with a suspension of charged material such as silica, as described above. Silica impregnation in half 321a is illustrated in cross section by small circles in half 321a (compare cross sections of 321a to 321b in FIGS. 8, 10 and 12). The other half 321b is not impregnated with a charged material. When alternative test pad 320 is used in alternative embodiment device 200, the pattern of holes 231 in volume control cover sheet 230 has to be changed from a circular pattern to two parallel lines of holes. The lines of holes are spaced such that from six to ten openings will overlie each half 321a and 321b of sheet 321. Thus when a user wipes with device 200, six to ten dots of fecal material 40 will be deposited on each half 321a and 321b of sheet 321 (FIG. 9). To determine the fecal occult blood content of the dots of fecal material 40 as applied to test pad 320, several drops of solvent/developer solution 150 are deposited generally along the centerline which divides top sheet 321 into halves 321a and 321b (FIGS. 9 and 10). As discussed above, solvent/developer 150 comprises 0.05 normal acetate buffer and 1% hydrogen peroxide in an ethanol water mixture, wherein ethanol comprises 60 to 80% of volume of the solution (FIGS. 10 and 12). As the solvent developer spreads away from the center of sheet 321, it will carry any hemoglobin present from the lower intestine towards the ends of sheet 321 and past the ends of solvent impermeable barrier 323. The hemoglobin is indicated by shading on FIG. 10. The hemoglobin will thus continue to migrate down into the guaiac impregnated lower sheet 320a where oxygen released by the hemoglobin-peroxide peroxidase reaction will immediately cause the guaiac dye to color blue. Thus blue colored patches will appear at each end of sheet 321, on the exposed ends of sheet 320a (FIG. 9). In contrast, if the only fecal occult blood in fecal material 40 comes from the upper intestine, it will comprise hematin and other hemoglobin breakdown products which are charged. Alternatively, if only dietary blood or other dietary peroxidase is present, it will also be charged. These charged blood particles will "stick" to the silica impregnated half 321a of sheet 321. Thus, the hematin and hemoglobin breakdown products and other dietary false-positives will not migrate as the solvent/developer 150 passes through them. These materials (indicated by shading in FIG. 12) will not migrate to the left end (as viewed in FIG. 11) of sheet 321. On the other hand, both hematin and hemoglobin breakdown products will migrate through the right half 321b of sheet 321, past the end of barrier 323 and downwardly into the lower guaiac impregnated sheet 320a. Thus where blood in fecal material 40 has originated in the upper intestine, or comprises a dietary false-positive, it will create colored patches only at the right end of guaiac impregnated sheet 320a (FIGS. 11 and 12). Of course, it is understood that the foregoing is a preferred embodiment of the invention and that various changes and alterations can be made without departing from the spirit and broader aspects thereof.

4y

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a Submission Under 35 U.S.C. §371 for U.S. National Stage Patent Application of International Application Number: PCT/EP2011/065494, filed Sep. 7, 2011 entitled “METHODS OF MANUFACTURING PHOTOVOLTAIC ELECTRODES,” which claims priority to Irish Patent Application Serial No: S2010/0550, filed Sep. 7, 2010, and Irish Patent Application Serial No: S2011/0125, filed Mar. 16, 2011 the entirety of both which are incorporated herein by reference. TECHNICAL FIELD This invention relates to the manufacture of photovoltaic electrodes, and in particular to the manufacture of dye-sensitized solar cells. BACKGROUND ART Dye-sensitized solar cells (DSSCs) show considerable potential as a relatively low cost alternative to silicon based solar cells. These cells were developed by Gratzel and co-workers in 1991 [B. O'Regan, M. Gratzel, Nature, 353 (1991) 737-740] and there is currently a considerable focus on enhancing their light conversion efficiency and stability. The principal components of a DSSC electrode are a conducting substrate, which is usually a transparent conductive oxide coated on glass, a highly porous layer of semiconductor material, and a photosensitive dye absorbed into and coating the porous semiconductor. In the case of conventional DSSCs, dye sensitization involves solely the semiconductor anode made of n-type TiO 2 nanoparticles. The counter electrode is generally a metallic cathode with no photoelectrochemical activity. To date the highest conversion efficiency obtained of 11% [M. K. Nazeeruddin, F. De Angelis, S. Fantacci, A. Selloni, G. Viscardi, P. Liska, S. Ito, B. Takeru, M. Gratzel, Journal of the American Chemical Society, 127 (2005) 16835-16847], is less than the best silicon based thin-film cells. A method of further enhancing the light conversion efficiency as suggested by He et al. [J. He, H. Lindström, A. Hagfeldt, S.-E. Lindquist, Solar Energy Materials and Solar Cells, 62 (2000) 265-273] is to substitute the cathode with a dye-sensitized photoactivep-type metal oxide. This tandem dye-sensitized solar cell design utilizes more of the solar spectrum. The efficiency, however of p-type metal oxides is still very low, which limits their effectiveness in tandem DSSCs. Amongst the potential reasons highlighted for the poor conversion efficiency of the cathode within tandem DSSC, the more critical are the inefficient light absorption capability, poor charge injection efficiency and charge transport rate, along with inner resistance. The most widely used n-type electrode material is nanostructured titanium dioxide. For p-type electrodes, perhaps the most promising technology employs nickel oxide (NiOx) coatings, which has a considerable potential for use as a cathode in tandem cells. This is due to their p-type nature, excellent chemical stability, in addition to well defined optical and electrical properties. Moreover, NiOx is considered as a model semiconductor substrate due to its wide band-gap energy range from 3.6 to 4.0 eV depending on the amount of Ni(III) sites. NiOx films have been fabricated by various techniques which include spin coating, dipping, electrochemical deposition, magnetron sputtering and sol-gel. With the exception of the sputtering and electrochemical techniques, the other methods require a sintering step in order to obtain dense coatings. Thermal sintering also performs the function of removing the binder in the case of sol gel deposited coatings. Typically sintering conditions of 300-450° C. for 30 to 60 minutes are reported. A disadvantage with thermal sintering is the processing time. When one adds the heat-up and cool-down times, it can take approximately 4 hours to process a substrate. Further disadvantages with conventional thermal sintering include the photovoltaic performance of photocathodes produced according to this method and the probably related physical shortcomings of such photocathodes, such as the adhesion between the substrate and the nanoparticular NiOx layer, the post-sintering average particle size, the pore characteristics, and the dye absorption. The present invention aims to address at least some of these shortcomings and to provide improvements in the manufacture of photovoltaic electrodes. DISCLOSURE OF THE INVENTION There is provided a method of manufacturing a photovoltaic electrode, comprising the steps of: (a) depositing on a substrate a dispersion comprising powdered semiconductor particles in a dispersion medium; (b) removing the majority of the dispersion medium to leave the powdered semiconductor particles in a deposition layer on the substrate; (c) creating a plasma using microwave energy excitation; (d) exposing the deposition layer to said microwave-excited plasma for a sufficient time to sinter the nanoparticles thereby adhering them to the substrate; and (e) absorbing a dye into said sintered deposition layer. It has been found that one obtains a significantly better electrode using this method when compared to thermal sintering. Improvements have been found in the physical characteristics of the nanoparticle layer, its adhesion and electrical connectivity with the substrate, and the degree of dye absorption. In particular, it is found that the electrodes produced by this method have a surface exhibiting high porosity without sacrificing the mechanical stability of the resulting coatings. This surface morphology ensures higher light absorption by the monolayer of adsorbed dye, while keeping an intimate contact between the particulate material and the dye molecules. This in turn reduces the inner resistance and hence improves the charge injection efficiency. It is hypothesized that the advantages of the invention can be attributed to a number of factors including the rapidity of heating and the bulk homogeneity of heating due to the materials interacting with “cold” microwaves coupled through a plasma instead of radiant heat in a conventional furnace. This avoids the outer surface “cooking”, i.e. a heat-affected outer zone which can hinder dye absorption, and it increases the adhesion between sintered particles and the underlying substrate relative to conventionally sintered electrodes. Details of the results will be given below. The net result is that electrical properties of the photovoltaic electrodes prepared according to this method are significantly improved (i.e. in some instances ten-fold or more) relative to the equivalent thermal sintered electrodes. Preferably, step (a) of depositing a deposition layer comprises depositing a layer of said powdered semiconductor particles in a dispersion medium, and removing a majority of said dispersion medium to leave the particles weakly bound to the substrate in a deposition layer. Preferably, said deposition step is selected from spraying, spin coating and sol gel deposition. In a preferred embodiment, the dispersion medium is heated before, during or after the deposition step to evaporate the dispersion medium. Preferably, this is done by heating the substrate. Evaporation may also be achieved without heating by choosing a suitable dispersion medium which evaporates at ambient temperatures. The method involves removal of the majority of the dispersion medium. More preferable, substantially all of the dispersion medium is removed, so that the deposition layer is a substantially dry layer on the substrate. Preferably, said powdered semiconductor particles have a maximum particle size of 20 microns. More preferably, said powdered semiconductor particles have a maximum particle size of 500 nm. More preferably, said powdered semiconductor particles are nanoparticles with a maximum particle size of 100 nm. Preferably, said powdered semiconductor particles are metal oxide particles. The invention has particular application in metal oxide particles such as nickel oxide and titanium dioxide. A further application of this technology is the fabrication of CIGS (copper indium gallium selenide) solar cells if the correct ratio of the different powders is homogeneously mixed. Particularly advantageous results are found using nickel oxide nanoparticles, and with Erythrosin B dye (2′,4′,5′,7′-tetraiodofluorescein, disodium salt). Preferably, in step (c), the deposition layer is exposed to said microwave plasma for between 2 and 20 minutes, more preferably between 4 and 15 minutes. Preferably, the method further comprises the step of depositing on the substrate an adhesion enhancing agent to enhance adhesion between the semiconductor particles and the substrate. The adhesion enhancing agent is preferably a metal compound which is reactive in the presence of water vapour to form a metal oxide. Preferably said semiconductor particles comprise the same metal oxide as is formed by the reaction of said metal compound with water vapour. Preferably, the metal oxide is selected from nickel oxide, titanium dioxide, tin oxide, indium tin oxide and zinc oxide. Preferably, the metal compound is a metal alkoxide or metal halide of the same metal as is present in said metal oxide with the proviso that the metal alkoxide or metal halide is reactive in the presence of water vapour to form said metal oxide. Where the metal oxide is titanium dioxide, the compound is preferably selected from the group of titanium tetrachloride, titanium alkoxides (including in particular titanium isopropoxide and titanium butoxide) and precursors thereof Preferably, the adhesion enhancing agent is dispersed in an organic carrier which is substantially free of water. Particularly suitable carriers include isopropanol and tertbutanol. When the solvent or carrier evaporates, the metal compound reacts with water vapour in the air to form an amorphous layer of metal oxide. The step of depositing an adhesion enhancing agent preferably occurs prior to step (a) of depositing on the substrate a dispersion comprising powdered semiconductor particles in a dispersion medium. In this way, the dispersion of powdered semiconductor particles is deposited on an intermediate layer of the adhesion enhancing agent. Alternatively, the adhesion enhancing agent is co-deposited with the semiconductor nanoparticles in the same dispersion medium, such that this step occurs as part of the deposition step (a). In a further alternative, the adhesion enhancing agent is deposited on the substrate in a first layer together with the semiconductor nanoparticles, following which a layer of semiconductor nanoparticles is deposited without adhesion enhancing agent. Optionally, a sandwich structure of layers can be created by repeating one or more of these depositions (e.g. a three-layer sandwich, or a multi-layer repeating sandwich structure of layers with and without the adhesion enhancing agent. BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be further illustrated by the following descriptions of embodiments thereof, given by way of example only with reference to the accompanying drawings, in which: FIG. 1 is a schematic illustration of an apparatus used to manufacture a photovoltaic electrode; FIG. 2 shows the XRD spectra of various samples of microwave plasma sintered NiOx coatings, sintered for between 1 and 10 minutes from which crystallite size information was calculated using the Scherrer equation; FIG. 3 shows the comparative XRD spectra of NiOx coatings sintered for 5 minutes using a furnace and using the microwave plasma technique, from which crystallite size information was calculated using the Scherrer equation; FIG. 4 is a plot of the UV-vis absorbance spectroscopy of the microwave plasma sintered samples from FIG. 2 (treated for between 1 and 10 minutes), after having been dye sensitized with Erythrosin B; FIG. 5 is a comparative plot of the UV-vis absorbance spectroscopy for dye-sensitized NiOx coatings sintered for 5 minutes using a furnace and using the microwave plasma technique; FIG. 6 shows the current density vs. applied potential curves for 5 minute RDS sintered NiOx coatings sensitized with ERY; FIG. 7 shows the photovoltaic performance of ERY sensitized NiOx coatings when assembled in a photovoltaic cell and measured under standard conditions using an AM 1.5 solar simulator (I: 870 W m −2 ); FIG. 8( a ) shows the FIB-SEM cross-section image of the NiOx sample sintered for 5 minutes in a furnace; FIG. 8( b ) shows the FIB-SEM cross-section image of the NiOx sample sintered for 5 minutes in the microwave plasma apparatus; FIG. 9( a ) shows the FIB-SEM cross-section image of a TiO 2 sample sintered for 30 minutes in a furnace; FIG. 9( b ) shows the FIB-SEM cross-section image of a TiO 2 sample sintered for 5 minutes in the microwave plasma apparatus; FIG. 10 shows the comparative XRD spectra of TiO2 coatings sintered for 5 minutes using the microwave plasma technique and for 30 minutes using a furnace at 500 degrees C.; and FIG. 11 shows a nebulizer used for spraying dispersions onto a substrate; FIG. 12 is a photograph of a sample employing a polymeric substrate and TiO 2 coating when held in place with a glass slide on a cooling stage; FIG. 13 is a photograph of a sample employing a polymeric substrate and TiO 2 coating following plasma treatment when an intermediate sample holder is employed between the polymer and the cooling stage; FIGS. 14 a - 14 e show the results of subjecting samples to Rockwell tests ( FIGS. 14 a and 14 b ) and bending tests ( FIGS. 14 c , 14 d and 14 e ); FIG. 15 shows a cross-sectional comparative analysis of the adhesion between a TiO2 coating and a substrate when deposited without TIP and when TIP is used as a co-depositing layer; FIG. 16 is a pair of SEM micrographs of the top surface of TiO 2 coatings after deposition and after subsequent plasma treatment; FIG. 17 shows the IV curves of TiO 2 coatings on ITO-PEN substrates when subjected to different sintering techniques and when compared with TiO 2 coating on an FTO-glass substrate; FIG. 18 is a photographic illustration of the flex test method; and FIG. 19 shows the IV curves of cells of dyed TiO 2 coatings which had been previously subjected to repeated bending at 20 degrees before assembly of the cells. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS EXAMPLE 1 NiOx Nanoparticles on FTO Glass Substrate Sample Preparation In order to prepare photovoltaic electrodes, fluorine doped tin oxide (FTO) glass substrates (3 mm thick) supplied by Mansolar. The glass substrates (2×2 cm) were ultrasonically cleaned in propanol followed by acetone, each for 5 minutes. Other typical substrates which may be used include indium doped tin oxide (ITO) glass and polymers e.g. PET. A deposition layer medium was made, comprising NiOx nanoparticles (˜50 nm) suspended in methanol (20 mg/ml) as a dispersion medium. This deposition layer medium was deposited by spraying using a nebulizer (Burgener Mira Mist atomizer) which uses an inert gas to break up the suspension into small aerosol droplets. In this case, the inert gas used was nitrogen at a flow rate of about 2 liters/min. The nebulizer was moved over the surface of the substrate in a raster pattern using a computer numeric control (CNC) device with a line speed of 20 mm/s and a step interval of 1 mm. The distance from the tube orifice to the substrate was fixed at 10 mm. During deposition, the glass substrates were mounted over a heating block to maintain the substrate temperature at approximately 50 degrees C. The methanol evaporated once deposited to leave a layer of loosely bound NiOx nanoparticles on the substrate. Samples prepared in this way were subjected to microwave plasma processing as will now be described with reference to FIG. 1 . Some comparative tests were done against samples prepared in the same way but subjected to conventional furnace sintering in air using a Carbolite Furnace (RHF 1200). Microwave Plasma Processing FIG. 1 shows an apparatus used in the manufacture of a photovoltaic electrode, comprising a plasma chamber 10 which is pressure controlled using a gas supply inlet 12 and a vacuum outlet 14 . In the processes described below, the pressure was controlled to form a plasma at a pressure of 20 mbar in an argon and oxygen atmosphere in a ratio 10:1 (argon:oxygen). A sample stage 16 is located within the chamber 10 to support one or more substrates (not shown) upon a sample holder 18 for processing. The sample stage is height-adjustable, rotatable, and is water-cooled. In the set-up used to generate the results described herein, three samples were treated at a time upon the sample holder 18 . A Muegge microwave power supply 20 operating at 2.4 kW and 2.45 GHz provides microwave energy 22 via a tunable waveguide 24 having a tuner 26 , through a quartz window 28 into the chamber 10 , where it excites a plasma ball 30 located above the sample holder 18 . Substrate temperatures were measured using a LASCON QP003 two-colour pyrometer (not shown) from Dr Merganthaler GmbH & Co. Sample Characterisation The NiOx film thickness was measured by step height measurement using a WYKO NT1100 optical profilometer in vertical scanning interferometry (VSI) mode. For the cross sectional investigations, the coatings were mounted on stubs using double-sided carbon tape, and sputter coated with platinum, using a Emitech K575X sputter coating unit, to prevent surface charging by the electron beam. Samples were then examined using a FEI Quanta 3D FEG DualBeam (FEI Ltd, Hillsboro, USA). X-ray Diffraction (XRD) measurements were carried out using a Siemens D500 diffractometer operating at 40 kV and 30 mA with Cu Kα radiation in normal diffraction mode at 0.2°/min scan rate. Dye Sensitization, UV-vis Measurements and IV-Characteristics NiOx coatings were sensitized with 0.3 mM Erythrosin B (ERY) dye, in a 99.8% ethanol solution for 24 h. The dye adsorption was investigated in transmission mode using an AnalytikJena Specord 210 UV-vis spectrophotometer in the wavelength range of 350-700 nm. The photovoltaic performance (I-V characteristic) of dye sensitized NiOx coatings were analyzed in two electrode configuration using 870 W m −2 AM 1.5 solar simulator and platinum coated FTO was used as a counter electrode. The p-type behavior of ERY-sensitized NiOx coatings was observed using a custom made photoelectrochemical cell in three-electrode configuration: Working electrode was ERY-NiOx on FTO; counter electrode was platinum, where SCE was utilized as a reference electrode. The Electrolyte was 0.5 M LiI and 0.05 M I 2 in Propylene Carbonate (from Sigma-Aldrich). Results and Discussion Loosely adherent NiOx particulate layers were prepared from the metal oxide/methanol slurry using the spray technique described above. The layer thickness was maintained between 1-2 μm. Referring to FIG. 2 , the effect of sintering time on crystallite size was evaluated for samples sintered from 1 to 10 minutes using the microwave plasma sintering technique described above, prior to addition of the dye. For brevity, this microwave plasma sintering technique is referred to as “rapid discharge sintering” or “RDS”. FIG. 2 shows the X-ray diffraction data in the NiO (200) plane for samples sintered for 1, 3, 5, 7 and 10 minutes. Using the Scherrer equation to examine the XRD data, an increase in crystallite size from 6.5 to 19.0 nm was observed on increasing the sintering time from 1 to 10 minutes. The Scherrer formula gave a crystallite size of 6.5 nm for each of the samples sintered for 1 minute, 3 minutes and 5 minutes. For the sample sintered at 7 minutes the crystallite size was calculated at 12 nm, while for 10 minutes the size was 19 nm. Referring to FIG. 3 , in order to compare the performance of RDS technique with conventional furnace treatments, the NiOx coatings were also sintered at 450° C. for 5 minutes in a box furnace. The properties of the furnace sintered coatings were then compared with those obtained using the RDS technique. XRD examination of the sintered NiOx coatings demonstrated a significantly smaller crystallite size of 6.5 nm for the microwave plasma sintered samples, as compared to the 14 nm obtained after the furnace treatment. Thus the smaller grain size along with more homogeneous heating/sintering is achieved using the RDS technique thus helping to maintain the mesoporous structure of the NiOx nanoparticles. Referring to FIG. 4 , after treatment of the RDS samples with the ERY-B dye, the UV-vis absorption spectra of the samples prepared under different sintering times showed a gradual decrease of the amount of adsorbed dye for the coatings with the smaller crystallite size to those with the largest crystallites. The line with the highest peak in FIG. 4 is the reference of the ERY-B dye in solution. Referring to FIG. 5 , comparative data can be seen for the 5 minute RDS sample and the 5 minute furnace sintered sample. Again the reference is shown for ERY-B solution. From this it can be seen that the RDS sample has a far greater degree of dye absorption, probably due to rougher surface morphology. FIG. 6 shows the p-type behavior of ERY-sensitized NiOx coatings (RDS5). The curves in dark and under UV illumination demonstrated cathodic photocurrents of ERY-sensitized NiOx coatings with an onset of photocurrent at approximately +120 mV vs. SCE reference. Next, the open current photovoltage (V OC ), the short circuit photocurrent density (I SC ) and overall photocurrent efficiency (η), were measured as a function of sintering time. FIG. 7 details the I-V characteristics of the ERY sensitized NiOx coatings sintered at different times (thickness: 1-2 μm). Though dye adsorption levels were higher for the 1 minute sintered coatings, the 5 minutes sintered sample (RDS5) exhibited the highest efficiency. These sintering conditions facilitate a high level of dye diffusion, while maintaining interconnectivity between individual oxide grains. Thus the mesoporous sintered metal oxide structure facilitates efficient charge injection from the ERY dye. A subsequent study with 2.5 μm thick NiOx coatings also demonstrated a similar trend. FIG. 8 shows focused ion beam/scanning electron microscope (FIB/SEM) cross section images of NiOx coatings obtained after 5 minute sintering using (a) the furnace and (b) microwave plasma. In each image, one can see the sintered NiOx layer 34 , the FTO layer 36 , and the underlying glass substrate 38 . It is clear from these images that the RDS sintered coating exhibits a higher level of bonding at the interface 40 between the NiOx coating and FTO layer, as seen by the elimination of the dark gap seen a this interface in FIG. 8( b ). A possible explanation for this is that the RDS treatment involves volumetric heating, which provides more effective heating inside the metal oxide coating matrix than obtained with the conductive heating obtained using the furnace. Indeed the latter treatment may give rise to selective heating of the outer surface of a coating to produce a heat affected zone [ 37 ]. From FIG. 8 it is also clear that the RDS sintered oxide yields a much rougher surface morphology, which would also assist dye adsorption ( FIG. 3 b ). Finally, the photovoltaic performances (open circuit voltage, short circuit current, fill factor, and percent efficiency of both RDS5 and CS5 (i.e. the notation CS5 denotes the 5 minutes furnace sintered sample) coatings were measured as detailed in Table 1, and comparative values are given for two of the best performing electrodes as reported in the literature, namely He et al. [J. He, H. Lindström, A. Hagfeldt, S.-E. Lindquist, Solar Energy Materials and Solar Cells, 62 (2000) 265-273] and Nattestad et al. [A. Nattestad, M. Ferguson, R. Kerr, Y-B. Cheng, U. Bach, Nanotechnology, 19 (2008) 295-304]. The measurements carried out by He and by Nattestad were also obtained under the same test methodology. The Nattestad results were obtained using the dye Erythrosin-J rather than the Erythrosin-B The furnace sintered coatings reported here are broadly similar in efficiency to the values reported in the literature while those obtained with the RDS treatment exhibit significantly higher performance, i.e. a tenfold increase of conversion efficiency was observed for the 5 minute RDS sintered NiOx coatings as compared to the 5 minute furnace sintered sample. Results are given in Table 1 for samples sintered in the furnace for both 5 minutes (CS5) and 30 minutes (CS30). Sintering Sample time V OC I SC Efficiency (NiO thickness) (min.) (mV) (mAcm −2 ) FF (%) Rapid Discharge 5 120.00 1.05 36 0.0450 Sintered (RDS5) (~2.5 μm thick) Furnace Sintered 5 84.00 0.22 25 0.0050 (CS5) (~2.5 μm thick) Furnace Sintered 30 35.29 0.21 26 0.0023 (CS30) (~2.5 μm thick) He et al. (~1 μm thick) 60 83.00 0.20 27 0.0070 Nattestad et al. 20 120.00 0.36 26 0.0110 (~1.6 μm thick) Preparation of n-Type Electrode An n-type electrode based on titanium dioxide and ERY-B was made according to the same techniques as described above. Using the same FTO glass substrates, a deposition layer slurry was created using titanium dioxide nanoparticles (“Aerosil® P 25” from Evonik Industries) having an average particle size of 21 nm, and methanol (25 mg/ml). This mixture was again sprayed on the glass substrate using a nebulizer, in this case in a layer 9 microns thick, and samples were subjected to both conventional and microwave plasma sintering. FIG. 9 shows comparative FIB-SEM cross-section images for (a) conventionally sintered (at 500 degrees C. for 30 minutes) and (b) microwave plasma sintered samples sintered for 5 minutes. The SEM images again show the layers designated with the same reference numerals: sintered TiO2 layer 34 , FTO layer 36 , glass 38 and the interface 40 between the sintered TiO2 and the FTO substrate. As with the NiOx samples described above, one can again see that the RDS sample in FIG. 9( b ) exhibit far less of a gap at interface 40 , which strongly indicates better electrical connectivity and structural integrity relative to the CS sample in FIG. 9( a ). Accordingly, the technique of applying to a substrate a deposition layer including semiconductor particles, removing the dispersion medium, and then exposing the weakly bound particle layer to a microwave plasma under conditions leading to sintering of the particles, gives rise to a mesoporous semiconductor layer which is strongly bound with good electrical connectivity to the underlying substrate, and this has been demonstrated both for n-type TiO2 and p-type NiOx. In the case of the NiOx photocathodes, using the materials and methods described herein it can be seen that a 5 minute microwave plasma treatment cycle provides optimal conversion efficiency, and improved adhesion to FTO substrates compared with that obtained using furnace treatments. The 44% increase in the quantity of adsorbed dye in the case of the RDS treated coatings significantly contributed to the tenfold increase in light-to-current conversion efficiency, compared with that obtained with the furnace sintered coatings. This enhanced performance of the microwave plasma sintered coatings is associated with their smaller grain size after sintering, higher surface roughness and enhanced level of interconnectivity between grains in the mesoporous metal oxide structure. FIG. 10 shows the comparative XRD spectra of the box furnace treated and microwave plasma treated TiO2 coatings, and it can be seen that both exhibit very similar XRD spectra. EXAMPLE 2 TiO 2 Nanoparticles on Flexible Polymeric Substrate Sample Preparation Degussa P25 TiO 2 nanoparticles with an average size between 20-25 nm were deposited on ITO-PEN coated substrate (where ITO stands for indium doped tin oxide and PEN for polyethylene naphthalate). The TiO 2 was prepared in a suspension form by grinding the nanoparticles powder in an alumina mortar in order to breakdown the agglomerated particles. The ground paste was then transferred into a recipient using methanol solvent vehicle and diluted to a final concentration of 25-30 mg/ml and further sonicated using a sonication horn probe. The TiO 2 suspension was applied to the plastic substrate using a roll-to-roll spraying technique. In this technique the suspension is pumped through a nebulizer, shown in FIG. 11 , and with the assistance of a pressurised gas (nitrogen) is atomised and projected at the surface of the plastic substrate mounted onto a CNC controlled (X-Y-Z) pneumatic table. In addition to the TiO 2 suspension, a second suspension consisting of titanium isopropoxide (TIP) (20-25 mmol/l) precursor in propan-2-ol was co-applied using a second nebuliser. The titanium isopropoxide (TIP) is used to enhance the adhesion of the TiO 2 coating to the plastic substrate. The thickness of the TiO 2 coating (varying between 4 to 10 μm) is controlled by the amount of TiO 2 in the suspension and/or the number of passes of the nebuliser over the substrate. In the tests described below and illustrated with reference to FIGS. 12-19 the TiO 2 coatings had a thickness between 4 and 6 microns. This thickness will influence solar to electricity conversion efficiency due to parameters such as the electron transport properties of the coating structure. Also, the quantity of dye adsorbed will be influenced by the TiO 2 coating thickness. After the coating deposition the samples were allowed to relax for approx. 20 minutes to thoroughly evaporate the carrying vehicle, leaving the powdered semiconductor particles in a deposition layer on the substrate. Microwave Plasma Processing and Morphological Analysis Sintering of the dried TiO 2 coatings was then carried out in oxygen plasma generated using a 2.45 GHz microwave generator. The plasma gas pressure was maintained between 4-5 mbar with a sample treatment time of 5 minutes. The plasma processing apparatus was as shown and as previously described in relation to FIG. 1 , except that oxygen plasma was employed at 4-5 mbar instead of a 10:1 argon:oxygen mixture at 20 mbar (although argon:oxygen mixtures or other plasmas could equally be employed), and (2) a mask was overlaid on the sample as described below. The samples were held on the cooling stage of the microwave system using a mask (in this case a 1 mm thick glass slide) to ensure its flatness and intimate contact with the stage as illustrated in FIG. 12 . The presence of the cooling stage ensures the integrity of the polymeric substrate; as shown in FIG. 13 the use of an intermediate sample holder (in this case a glass cover as thin as 0.5 mm in thickness) resulted in melting the polymer. This is an indication that the plasma gas temperature exceeded 270-300° C. (as the melting temperature of PEN is reported to be 270° C.—see E. L. Bedia, S. Murakami, T. Kidate and S. Kohjiya; Polymer 42 (2001) 7299-7305). FIG. 14 shows results of the TiO 2 coatings subjected to Rockwell hardness test and bending tests. The coatings were found to easily flake off after indentation was applied to the substrate without the use of TIP precursor ( FIG. 14 a ) whereas stability was greatly improved in the same test carried out on a sample prepared with TIP precursor ( FIG. 14 b ). As shown in FIGS. 14 c , 14 d and 14 e , the use of TIP in the deposition process significantly improved the stability of the TiO 2 coating on the substrate both in initial condition ( FIG. 14 c ) and when bent through 20 degrees ( FIG. 14 d ) and 40 degrees ( FIG. 14 e ). The coatings were also evaluated using both High resolution scanning electron microscopy (HRSEM) and focus ion beam (FIB) cross sectional analysis. These analyses further confirmed the weakened nature of the adhesion of the TiO 2 coating deposited without TIP and its intimate contact with the substrate when TIP is used as a co-depositing layer (see FIG. 15 ). The SEM micrograph of the top surface of the TiO 2 coatings indicated micro-crack formation in the coating when deposited on the plastic substrate ( FIG. 16 ). This may be related to the spraying parameters and may be eliminated or significantly reduce by further optimisation of the deposition parameters. Electrical Characterization Further to the morphological analysis of the TiO 2 coating, the photovoltaic performance was assessed by assembling DSSC's and recording their current-voltage (IV) characteristics. FIG. 17 shows the IV curve of TiO 2 coatings on ITO-PEN substrates sintered in microwave plasma for 5 minutes or a conventional furnace for 60 minutes at 150° C. The IV curve of a TiO 2 coating on an FTO-glass substrate sintered at 500° C. for 60 minutes is also shown. Table 2 compares the conversion efficiency (η) of the same coatings. It is found that the PEN samples sintered in the microwave plasma exhibit 30-35% higher conversion efficiencies when compared to the one sintered in the furnace while it reaches 60% of the conversion efficiencies obtained on the FTO-glass substrate. Glass PEN Furnace PEN Microwave Conversion 5.68 2.08 3.15 Efficiency η (%) Furthermore the overall processing cycle time of the samples in the microwave system is only 10-15 minutes including the time taken for loading/unloading of the samples and pumping down of the system. FIG. 18 is a more detailed illustration of the steps involved in the flexing test, showing that a flex involved conforming the substrate and coating to both the interior (concave) surface of an annular cylinder and to the outer (convex) surface. FIG. 19 shows the IV curves of cells of dyed TiO 2 coatings subjected to repeated bending at 20° (as illustrated in FIG. 18 ) before assembling the cell. It is found that the bending does not alter the IV characteristics of the coatings.

4y

BACKGROUND OF THE INVENTION [0001] 1) Field of the Invention [0002] The invention relates to a wafer-type tumbler cylinder and key, the cylinder shaft of which facilitates the placement of the wafers and springs and, furthermore, enables the fabrication of a narrow width, corrugated contour keyway; at the same time, the key has a serrated blade, the fabricated cut surfaces of which result in a corrugated contour key. [0003] 2) Description of the Prior Art [0004] Conventional wafer-type tumblers, as shown in FIG. 14 , are typically comprised of a sleeve 1 a , a cylinder 2 a , and a plurality of wafers 3 a and their springs 4 a . The sleeve 1 a consists of a sleeve body 10 having a bore 11 extending through it lengthwise, a minimum of one lengthwise slot 12 disposed along the inside of the bore 11 , and a bearing edge 13 at the leading end of the bore 11 . As shown in FIG. 15 , the cylinder 2 a has a keyway 21 through the center and, furthermore, a flange 22 and a drive section 23 at the front and rear ends, with a shaft 20 movably installed in the bore 11 of the sleeve 1 a ; the shaft 20 has disposed one or more diametrically oriented, rectangular through-holes 24 and, furthermore, at the two sides of each rectangular through-hole 24 is a C-shaped recess 25 and a horizontally oriented U-shaped recess 26 (as shown in FIGS. 16 and 17 ), for the installation of one or more wafer 3 a and spring 4 a sets. The cylinder 2 a , after the installation of the wafers 3 a and their springs 4 a , is first fitted into the bore 11 of the sleeve 1 a and, furthermore, such that the one end of each wafer 3 a is subjected to the elastic force of its spring 4 a , and then postured against and inserted into the slot 12 inside the bore 11 , thereby obstructing the clockwise and counter-clockwise rotation of the cylinder 2 a situated in the bore 11 ; at the same time, the flange 22 at the front end of the cylinder 2 a is seated on the bearing edge 13 at the leading end of the bore 11 in order to inset securely the bore 11 ; additionally, the drive section 23 at the rear end of the cylinder 2 a is mounted with a lock tool or electric driver so as to check whether the tumbler is locked or electrified. [0005] Because each wafer 3 a of the conventional wafer-type tumbler, in addition to a window 31 in the middle thereof, has an opposing spring tab 32 and a locating tab 34 ; when the wafer 3 a is inserted into each rectangular through-hole 24 on the shaft 20 of the cylinder 2 a , it is first necessary to install a spring 4 a into the C-shaped recess 25 at one side of the rectangular through-hole 24 , following which the wafer 3 a is then inserted into the rectangular through-hole 24 ; but during the installation, since the wafer body 30 of the wafer 3 a has the spring tab 32 , its insertion occurs without any resistance along the C-shaped recess 25 ; however, the locating tab 34 , disposed in the other side of the wafer body 30 , must similarly undergo insertion through the C-shaped recess 25 along the rectangular through-hole 24 , and, as a result, friction occurs along the interior wall of the rectangular through-hole 24 at the lateral extent of the C-shaped recess 25 , and only after this does the wafer body 30 reach into the horizontally oriented U-shaped recess 26 , where it becomes nested onto the bottom of the horizontally oriented U-shaped recess 26 (as shown in FIGS. 16 and 17 ), and also only then is the cylinder 2 a installed in the bore 11 of the sleeve 1 a , which completes the assembly of one wafer-type tumbler mechanism. As such, during the insertion of each wafer 3 a into the rectangular through-hole 24 on the shaft 20 , the operation is difficult and adversely affects the production process. After each wafer 3 a has been inserted into the rectangular through-hole 24 , the locating tab 34 on the wafer body 30 is nested onto the bottom of the horizontally oriented U-shaped recesses 26 ; however, the height of the locating tab 34 is quite limited and, furthermore, the locating tab 34 is subjected to the outwardly exerted elastic force of the spring 4 a , the wafer 3 a is often ejected out of the rectangular through-hole 24 . Such situation results in a troublesome and inconvenient assembly operation as the cylinder 2 a is inserted into the bore 11 of the sleeve 1 a , which likewise adversely affects the production process. [0006] Moreover, based on the locking and unlocking structure of the conventional wafer-type tumbler, it depends entirely on the installation of the shaft 20 on the cylinder 2 a with a plurality of wafers 3 a ; hence, as indicated in FIG. 15 , the rectangular keyway 21 must be disposed through the center of the shaft 20 to facilitate insertion of the serrated blade 51 on the key 5 a (as shown in FIG. 19 ), which causes each wafer 3 a extending into the end of the slot 12 in the bore 11 to fully react within the outer diameter of the shaft 20 , thereby achieving the objective of locking or unlocking. Since the cylinder 2 a of the conventional wafer-type tumbler is typically made of aluminum-zinc alloy material in an integrated molding process, and the keyway 21 disposed through the center of the shaft 20 also penetrates the internal section of the shaft 20 ; as a result, it is not possible to mold a corrugated keyway having a narrow width. It's only possible to mold a keyway with a width of 1.5 mm or more, and as indicated in FIG. 14 , the shape of the keyhole 211 only can be formed as reverse Z-shaped or other similar contour, which has a triangular projecting element 212 at the two lateral inner sides of the keyhole 211 respectively (one triangular projecting element is concealed by the flange 22 , so it's not viewable); the keyway 21 along the internal section of the shaft 20 not only is formed as relatively wide rectangular shape, but also has disposed at most one lengthwise triangular projecting element 212 at one side of the keyway 21 , as indicated in FIGS. 15 and 18 . As a result, the prior art is easily broken by thieves and pried or unlocked by burglars. [0007] Due to the shape of the keyway 21 and its keyhole 211 on the shaft 20 of the cylinder 2 a in the conventional wafer-type tumbler, the design of which is formed as relatively wide rectangular and reverse Z-shaped contour, and furthermore, the two triangular projecting elements 212 are disposed in opposing position and at close distance along the two lateral inner sides of the keyhole 211 ; therefore, the serrated blade 51 of the key 5 a must be fabricated of a thicker metal plate. Even though the whole key 5 a may be formed by punching the metal plate, the serrated blade 51 (as indicated in FIGS. 19 and 20 ) must undergo milling or planing process to form as reverse Z-shaped section by means of a miller or planer, and it also has to undergo cutting or milling process to make a lengthwise V-shaped groove 511 at each of the lateral sides. Therefore, in terms of production, the process is extremely inconvenient and, furthermore, both time and labor consuming. [0008] In view of the serrated blade 51 of the conventional wafer-type tumbler cylinder and key, there are such inconveniences and shortcomings during the process of production and assembly; such production cost is greater and not cost-effective and also the theftproof capability of the prior art still remained deficient, so the inventor of the invention herein conducted research which culminated in the improved wafer-type tumbler cylinder and key of the present invention. SUMMARY OF THE INVENTION [0009] The objective of the invention herein is to provide a cylinder that better facilitates the installation of the wafers and their springs and, furthermore, facilitates the production of a shaft having a corrugated contour keyway with a narrower width to prevent from theft or using metal sheets and other equivalent tools to pry or unlock the wafer-type tumbler cylinder. [0010] Another objective of the invention herein is to provide a serrated blade of the key, wherein a very thin metal plate is punched to directly produce its sectional shape into a corrugated contour to prohibit theft by the replication of the wafer-type tumbler cylinder and key. [0011] To achieve the first objective of the invention herein, the shaft of the cylinder consists of a first and a second semicircular columnar body that are insertionally conjoined into an integration, and furthermore, respectively disposed at the front and rear ends of the first semicircular columnar body are a flange and a drive section; although, on the inner lateral surfaces of the first and second semicircular columnar bodies, one or more diametrically oriented U-shaped slots are disposed; only disposed in each U-shaped slot on the first semicircular columnar body are rectangular notches having fitted with the dimensions of the wafers as well as the springs, thereby facilitating the initial placement and positioning of each wafer and its respective spring into each said U-shaped slot and rectangular notch on said first semicircular columnar body, following which the second semicircular columnar body is then fitted thereon for assembling into an integration; thereafter, the cylinder, with the wafers and their springs installed already, is inserted into the shaft hole of said sleeve to complete the assembly of the wafer-type tumbler of the present invention. The operation for assemblage is easy, quick and convenient. [0012] When the flange and the drive section are respectively disposed at the front and rear ends of the first semicircular columnar body, an inverted U-shaped indentation is left at the inner lateral surface between said flange and drive section of the first semicircular columnar body; as the inner lateral surface of the first and second semicircular columnar body is molded, two corrugated half-keyways are respectively molded along the center, and furthermore, one or more posts and holes are molded at the front and rear ends. As such, the second semicircular columnar body, via the insertion of said posts through said holes, is installed with the first semicircular columnar body into an integration; thus, the keyway along the common center of the first and the second columnar bodies is formed as corrugated contour with a narrower width (approximately 0.5 mm), which effectively makes it impossible for thieves to pry or unlock by inserting metal sheets or other equivalent tools. [0013] Since the keyway disposed in the center of the shaft on the cylinder is extremely narrow in width (approximately 0.5 mm) and the sectional shape of the keyway is formed as corrugated contour, the serrated blade of the key is produced by directly punching a metal plate (approximately 0.5 mm in width), and also has a thicker plastic grip coated at the opposite end thereof to thereby facilitate the user holding the key for locking and unlocking the wafer-type tumbler. The production is extremely simple and convenient, but it's difficult to replicate by thieves. [0014] The shaft of the cylinder consists of a first and a second semicircular columnar bodies with identical shape and dimension, which are combined into an integration; furthermore, a semicircular tenon respectively disposed at the front and rear ends of each said semicircular columnar body enables, following the installation with a plurality of wafers and their springs, the respective fitting of a sleeve ring and a drive section onto the front and rear ends to thereby assemble one shaft. As such, it's convenient to produce and assemble different numbers of wafers into different length of shafts, and as the sleeve ring and the drive section are fitted thereon, it is quite convenient to manufacture longer or shorter shafts so as to assemble the wafer-type tumblers with different length or specifications. [0015] The shaft of the cylinder, between every two diametrically oriented U-shaped slots at the inner lateral side of the two semicircular columnar bodies, includes a relatively wider rectangular notch; at the same time, each of the wafers is a wafer body having a horizontal L-shaped tab; when each wafer is positioned between every two diametrically oriented U-shaped slots, only one spring is disposed in the relatively wider rectangular notch to serve as a common-use spring for every two wafers. Therefore, the component cost of the spring is reduced by half and it's able to prevent from prying effectively. BRIEF DESCRIPTION OF THE DRAWINGS [0016] FIG. 1 is an exploded drawing of the wafer-type tumbler of the invention. [0017] FIG. 2 is an exploded drawing of the wafer-type tumbler cylinder of the invention. [0018] FIG. 3 is a cross-sectional view of the invention herein when the wafer-type tumbler is not installed with wafers and when the serrated blade of the key is inserted. [0019] FIG. 4 is cross-sectional view of the invention herein when the wafer-type tumbler is interlocked. [0020] FIG. 5 is a cross-sectional view as the wafer-type tumbler is installed with one wafer and its spring. [0021] FIG. 5-1 is a cross-sectional drawing, as viewed from a perspective in FIG. 5 , to show the adjacent wafer and its spring of the invention herein. [0022] FIG. 6 is an orthographic drawing of the wafer-type tumbler key of the invention. [0023] FIG. 7 is a cross-sectional drawing of the serrated blade of the wafer-type tumbler key. [0024] FIG. 8 is an isometric drawing of the preferred embodiment of the cylinder in the present invention. [0025] FIG. 9 is an exploded drawing of the preferred embodiment of the cylinder in the present invention. [0026] FIG. 10 is a cross-sectional drawing of the invention herein, as viewed from the perspective of line 10 ˜ 10 ′ in FIG. 8 . [0027] FIG. 11 is an exploded drawing of another preferred embodiment of the cylinder with wafers and a spring. [0028] FIG. 12 is a vertically sectional view of the cylinder as viewed from the perspective in FIG. 11 . [0029] FIG. 13 is a cross-sectional drawing of the invention herein, as viewed from the perspective of line 13 ˜ 13 ′ in FIG. 12 . [0030] FIG. 14 is an exploded drawing of the conventional wafer-type tumbler. [0031] FIG. 15 is a cross-sectional drawing of the conventional wafer-type tumbler when the wafers are not installed. [0032] FIG. 16 is a cross-sectional drawing of the conventional wafer-type tumbler wherein a wafer and it spring are disposed. [0033] FIG. 17 is a cross-sectional drawing, as viewed from a perspective in FIG. 16 , to show the adjacent wafer and its spring. [0034] FIG. 18 is a cross-sectional view of the conventional wafer-type tumbler when the serrated blade of the key is inserted. [0035] FIG. 19 is an orthographic drawing of the conventional wafer-type tumbler key. [0036] FIG. 20 is a cross-sectional view of the serrated blade of the key in the conventional wafer-type tumbler. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0037] Referring to FIG. 1 , the wafer-type tumbler of the invention herein, in common with the above-mentioned conventional wafer-type tumbler, is comprised of a sleeve 1 , a cylinder 2 , a plurality of wafers 3 and their springs 4 ; the structure of the sleeve 1 and the method for installing with the cylinder 2 are the same as those of said conventional wafer-type tumbler. There is no need to go into details. However, a shaft 20 of the cylinder 2 , as shown in FIG. 2 , consists of a first and a second semicircular columnar body 20 a and 20 b that are integrated with each other; furthermore, respectively disposed at the front and rear ends of the first semicircular columnar body 20 a are a flange 22 and a drive section 23 ; at the inner lateral surface between said flange 22 and drive section 23 is an inverted U-shaped indentation 201 , the length of which matches with the second semicircular columnar body 20 b so as to complete the assembly of the shaft 20 on the cylinder 2 (as indicated in FIG. 1 .) On the inner lateral surfaces of the first and the second semicircular columnar body 20 a and 20 b , one or more diametrically oriented U-shaped slots 24 a and 24 b are disposed for the installation of said wafers 3 ; however, only in each of the U-shaped slots 24 a on said first semicircular columnar body 20 a is disposed a rectangular notch 27 matching the dimension of the spring 4 , thereby facilitating the placement of each wafer 3 and its spring 4 into each said U-shaped slot 24 a and said rectangular notch 27 on said first semicircular columnar body 20 a , following which the second semicircular columnar body 20 b is then fitted thereon for an integral unity; after that, the shaft 20 of said cylinder 2 is inserted into a shaft hole 11 in said sleeve 1 to assemble the wafer-type tumbler of the present invention, as illustrated in FIG. 5 as well as FIG. 5-1 . [0038] When said first and second semicircular columnar body 20 a and 20 b are molded into shape, two half-keyways 21 a and 21 b are formed as corrugated contour in the center of the inner lateral surfaces thereof; furthermore, one or more posts 28 (as shown in FIG. 2 ) and holes 29 (which are concealed by the second semicircular columnar body 20 b , so please refer to FIG. 4 ) are disposed at the front and rear ends of each said inner lateral surface. As such, the second semicircular columnar body 20 b , via the insertion of said posts 28 through said holes 29 , is correspondingly fixed with the first semicircular columnar body 20 a into a unity so as to complete the assemblage of the cylinder 2 , as indicated in FIGS. 1 , 3 and 4 ; at the same time, along the common center of the first and second semicircular columnar body 20 a and 20 b , a keyway 21 (as shown in FIG. 4 ) is formed as corrugated contour, with a narrower width of 0.5 mm, thereby preventing theft by means of a metal sheet or other equivalent tool inserted for burglarizing. [0039] Since the keyway 21 disposed at the center of the cylinder 2 is approximately 0.5 mm in width and is fabricated as corrugated passage, a serrated blade 51 of a key 5 (as depicted in FIGS. 6 and 7 ) is produced by directly punching an approximately 0.5 mm or thinner metal plate, and a plastic grip 52 is coated onto the opposite end thereof, thereby facilitating the user holding the key for locking and unlocking the wafer-type tumbler; it is not necessary to mill and plane any lengthwise grooves nor other milling and planing processes. To facilitate the insertion of said very thin serrated blade 51 into the keyway 21 in the shaft 20 of the cylinder 2 , it is then necessary, in the center of the flange 22 at the front end of said shaft 20 , to dispose a rectangular, flared keyhole 211 that is in line with said keyway 21 . As for the drive section 23 at the rear end of said shaft 20 , in addition to the depiction shown in FIG. 1 and FIG. 2 wherein the drive section 23 is shaped as square or rectangular rod body 230 , said drive section 23 may be shaped as threaded, circular, oblate, tubular or other shaped rod body (not shown in the drawings) to make the design of said drive section 23 match with a lock tool or electric driver, thereby enabling said drive section 23 to fasten with said lock tool or electric driver by means of screws or rivets. [0040] Furthermore, since the wafers 3 of the wafer-type tumbler of the invention herein do not require mounting in rectangular through-holes 24 (as depicted in FIG. 14 of the prior art), said wafers 3 can be fixed on said shaft 20 securely, as shown in FIG. 1 , by a window 31 in the center of each wafer body 30 of the wafer 3 along with a spring tab 32 at one side thereof, and there is no need to dispose any locating tab 34 thereon. [0041] Referring to FIGS. 8 and 9 , these two figures are isometric and exploded drawings of the preferred embodiment of a cylinder 2 ′ of the present invention. A shaft 20 ′ on the cylinder 2 ′ consists of a first and a second semicircular columnar body 20 ′ a and 20 ′ b (both of identical shape and dimension) that are conjoined into an integral unity; furthermore, respectively disposed at the front and rear ends of each semicircular columnar body 20 ′ a and 20 ′ b is a semicircular tenon 202 and 203 which is respectively fitted onto a sleeve ring 22 a and a drive section 23 to constitute a cylinder 2 ′, as indicated in FIG. 8 . The said semicircular tenons 202 at the front ends of said semicircular columnar body 20 ′ a and 20 ′ b are correspondingly coupled to form a circular tenon, and the said semicircular tenons 203 at the rear ends thereof are correspondingly coupled to form a circular tenon. To enable the precise placement of the sleeve ring 22 a and the drive section 23 onto the front and rear ends of the integrated semicircular columnar bodies 20 ′ a and 20 ′ b , as well as to prevent dislodging and comparative rotation, the sleeve ring 22 a has an inner hole 221 in a ring body 220 a , which is a D-shaped hole with a minimum of one secant planar edge 222 along one lateral wall, and furthermore, an opening 223 through one side of the ring body 220 a , wherein the center of said opening 223 is aligned and parallel with said secant planar edge 222 ; a facet 204 is disposed correspondingly along the outer extent of the semicircular tenon 202 of the semicircular columnar body 20 ′ b . As such, the circular tenon that is coupled by means of said semicircular tenons 202 at the front ends of said semicircular columnar body 20 ′ a and 20 ′ b is installed with the sleeve ring 22 a , and then a drill is used, through the opening 223 , to pierce into the front semicircular tenon 202 having said facet 204 thereof, thereby enabling the insertion of a pin 6 for securing and fixing, as depicted in FIG. 10 . [0042] Additionally, the drive section 23 , along the inner end of its square or rectangular rod body 230 , has an extended sleeve 231 so as to enable the conjoinment with the circular tenon coupled by means of the semicircular tenons 203 at the rear ends of said semicircular columnar body 20 ′ a and 20 ′ b. [0043] The extended sleeve 231 has disposed a D-shaped cavity 234 having a minimum of one secant planar edge 232 along the inner wall at one side thereof such that an aperture 233 is formed at one side of the extended sleeve 231 , of which the center is aligned and parallel with said secant planar edge 232 ; similarly a facet 204 is correspondingly disposed along the outer extent of the semicircular tenon 203 at the rear end of said semicircular columnar 20 ′ b . As such, the semicircular tenons 203 are assembled into a circular tenon, which is installed with said extended sleeve 231 , and in common with the depiction shown in FIG. 10 as well as previous arrangement, a pin 6 a illustrated in FIG. 9 is fixed with said extended sleeve. [0044] As for the molding process of said first and second semicircular columnar bodies 20 ′ a and 20 ′ b with identical shape and dimension, the structural and installation arrangement of the corresponding half-keyways 21 a , 21 b and the rectangular notches 27 ′, the integration of more than one pair of posts 28 and holes 29 , as well as the arrangement of wafers 3 and their springs 4 , are the same with the first and second semicircular columnar body 20 a , 20 b of the cylinder 2 in the first embodiment of the invention herein; therefore, it shall not be further elaborated. Furthermore, the semicircular tenons 202 and 203 disposed on the two ends of the first and second semicircular columnar bodies 20 ′ a and 20 ′ b , in addition to the shape of semicircle, they may also be shaped as semi-square, semi-rectangular, semi-hexagonal or semi-polygonal tenons, or even as semi-oval or semi-oblate tenons; moreover, the shape of the inner hole 221 in the ring body 220 a of the sleeve ring 22 a accords with that of the D-shaped cavity 234 in the extended sleeve 231 on the drive section 23 ; at the same time, the shape of the rod body 230 on said drive section 23 may also be disposed as threaded, circular, oblate, tubular or other shaped rod body (not shown in the drawings.) [0045] FIG. 11 is an exploded drawing of another preferred embodiment of the shaft 20 of the cylinder 2 ′ in the invention herein with wafers 3 and a spring 4 . Said shaft 20 also consists of a first and second semicircular columnar body 20 ′ a and 20 ′ b with identical shape and dimension, which are conjoined into an integral unity, and the preferred embodiment of the semicircular columnar bodies 20 ′ a and 20 ′ b , between every two diametrically oriented U-shaped slots 24 a and 24 b disposed in the inner lateral surfaces thereof, is modified by disposing a relatively wider rectangular notch 27 ′; meanwhile, each wafer 3 is modified by disposing a horizontal L-shaped tab 33 at one side of its wafer body 30 . As such, between every (or every two) correspondingly U-shaped slot 24 a , 24 b of each semicircular columnar body 20 ′ a and 20 ′ b is installed a wafer 3 respectively, and only one spring 4 is positioned in each relatively wider rectangular notch 27 ′, wherein said spring 4 is served as a shared spring for every two wafers 3 a and 3 b , as shown in FIGS. 12 and 13 . This embodiment of the shaft 20 on the cylinder 2 ′ can similarly be utilized in the preceding embodiment of the shaft 20 on the cylinder 2 .

4y

TECHNICAL FIELD The present invention relates to supports for drainage devices and in particular to a hanger for drainage systems which remove gases and fluids from medical patients, such as from the chest cavity, by means of pressure differentials. BACKGROUND ART For many years, the standard apparatus for performing the evacuation of the pleural cavity was a drainage system known as the "3-bottle set-up" which includes a collection bottle, a water seal bottle and a suction control bottle. A catheter runs from the patient's pleural cavity to the collection bottle, and the suction bottle is connected by a tube to a suction source. The three bottles are connected in series by various tubes to apply suction to the pleural cavity to withdraw fluid and air and thereafter discharge the same into the collection bottle. Gases entering the collection bottle bubble through water in the water seal bottle. The water in the water seal also usually prevents the back flow of air into the chest cavity. Suction pressure is usually provided by a central vacuum supply in a hospital so as to permit withdrawal of fluids such as blood, water and gas from a patient's pleural cavity by establishing a pressure differential between the suction source and the internal pressure in the patient. Such suction pressure and pressure differentials must be precisely maintained because of the dangerous conditions which could result if unduly high or low pressure differentials should occur. However, the bottles typically were placed on a support such as a table or floor and could be knocked over and the tubes pulled out accidentally. The 3-bottle set-up lost favor with the introduction of an underwater seal drainage system sold under the name "Pleur-evac"® in 1966 by Deknatel Inc. 1 U.S. Pat. Nos. 3,363,626; 3,363,627; 3,559,647; 3,683,913; 3,782,497; 4,258,824; and Re. 29,877 are directed to various aspects of the Pleur-evac® system which over the years has provided improvements that eliminated various shortcomings of the 3-bottle set-up. These improvements have included the elimination of variations in the 3-bottle set-up that existed between different manufacturers, hospitals, and hospital laboratories, such variations including bottle size, tube length and diameter, stopper material and the like. Among the features of the Pleur-evac® system which provide its improved performance are employment of 3-bottle techniques in a single, pre-formed, self-contained unit. The desired values of suction are generally established by the levels of water in the suction control bottle and the water seal bottle. These levels are filled according to specified values prior to the application of the system to the patient. A special valve referred to as the "High Negativity Valve" is included which is employed when the patient's negativity becomes sufficient to threaten loss of the water seal. Also, a "Positive Pressure Release Valve" in the large arm of the water seal chamber works to prevent a tension pneumothorax when pressure in the large arm of the water seal exceeds a prescribed value because of suction malfunction, accidental clamping or occlusion of the suction tube. The Pleur-evac®system is disposable and helps in the battle to control cross-contamination. The Pleur-evac® is provided with hanger hooks to permit supporting the device, for example, from a hospital bed. However, the hooks are easily removable from the device and are loosely attached which still permit dislodging the Pleur-evac® from its support by inadvertent jostling and the like. Despite the advantages of the Pleur-evac® system over the 3-bottle set-up and the general acceptance of the device in the medical community, there remains a continuing need to improve the convenience and performance of chest drainage systems and to render such systems compact. We have invented an improved hanger means for a drainage device which provides additional improvements to presently available devices. SUMMARY OF THE INVENTION The present invention is directed to an apparatus for supporting a housing from a support, comprising bracket member formed of at least one wall and having a post member extending therefrom, said post also capable of being positioned on the housing; and hook member having one end rotatably secured about the post member for selective rotational movement from a first storage position to a second hanging position, the other end of the hook member being configured for engagement with the support, the one end of the hook member and the bracket being configured and dimensioned so that the hook member remains locked in the hanging position. Preferably the one end is curved in a hook-like configuration with the smallest distance of separation of the hooked end being smaller than the diameter of the post member such that when the hook member is selectively rotated to the second hanging position, the hooked end can be moved away from the post member which is then securely advanced toward the smallest distance whereupon the hooked end resiliently spreads apart so as to lock the hook member in the second hanging position. A retention means is also provided which is configured for attachment to the housing so as to securely retain the hook member when in the first storage position. The other end of the hook member is curved so as to be capable of hanging from the support. In a preferred embodiment, a bracket and hook member are disposed on each of two opposite walls of the housing. In addition, the present invention relates to a drainage device for draining fluids from a portion of a body comprising a housing; collection chamber formed within the housing for collecting fluids including an inlet for entry of the fluids and for fluid communication with the body portion; suction control chamber formed within the housing and being in fluid communication with the collection chamber for regulating the degree of vacuum imposed in the collection chamber; and hanger means disposed on the housing for supporting the housing from a support, the hanger means comprising bracket member formed of at least one wall and having a post member extending therefrom, said post also capable of being positioned on the housing; and hook member having one end rotatably secured about the post member for selective rotational movement from a first storage position to a second hanging position, the other end of the hook member being configured for engagement with the support, the one end of the hook member and the bracket being configured and dimensioned so that the hook member remains locked in the hanging position. Preferably the housing is formed of a front wall member and a back wall member sealed together along their peripheries by a plurality of side wall members. Also the front wall member includes an integrally formed handle. The suction inlet and collection chamber inlet are each disposed in a first side wall common to the seal chamber and the collection chamber. Moreover, the ambient inlet to the suction control chamber is disposed in a second side wall adjacent to the first side wall. BRIEF DESCRIPTION OF THE DRAWINGS The present invention is described in greater detail hereinbelow, with reference to the drawings wherein: FIG. 1 is a perspective view of a chest drainage device supported in a hanging position with hangers according to the present invention. FIG. 2 is a top view of the drainage device of FIG. 1 illustrating a pair of hangers of the present invention positioned at the sides of the chest drainage device. FIG. 3 is an enlarged, partially exposed perspective view of one of the hangers of FIG. 1. FIG. 4 is an enlarged, partially exposed perspective view of an alternative embodiment of the hangers of the present invention. FIG. 4A is an enlarged, partially exposed side view of the hook member of FIG. 4 in a locked or secured position. FIG. 5 is a perspective view of a chest drainage device in a hanging position with an autotransfusion device attached to the side thereof. DESCRIPTION OF THE PREFERRED EMBODIMENTS In the description which follows, any reference to either orientation or direction is intended primarily for the purpose of illustration and is not intended in any way as a limitation of the scope of the present invention. Referring to FIG. 1, a chest drainage device 10 is illustrated with three chambers--a collection chamber 12 for retaining and storing fluids collected from a body cavity, a water seal chamber 14 for preventing any fluid from entering into the collection chamber 12 during high levels of negative pressure in the body cavity and a dry suction control chamber 16. The function and operation of these various chambers are generally described in U.S. Pat. Nos. 3,363,626; 3,363,627; 3,559,647; 3,683,913; 3,782,497; 4,258,824; and Re. 29,877 to the extent that like or common elements are presented therein. In addition, the purpose and general operation of the various chambers of the chest drainage device 10 of the present invention are also more fully described in the Deknatel Inc. Pleur-evac® publication entitled "Understanding Chest Drainage Systems" (1985) which is incorporated herein in its entirety. Accordingly, the disclosure of the aforementioned patents and publication are incorporated herein in their entirety. As shown in FIG. 1, the drainage device 10 is generally formed of a housing that includes a front wall 18 secured to a back wall 20 as shown in FIG. 2 by means of four side walls which include a top wall 22, right side wall 24, left side wall 26 and bottom wall (not shown). The housing can be formed integrally with all the walls formed along their peripheries or, alternatively the separate side walls and front and back walls can be secured to one another by means well known to those skilled in the art concerning securement or attachment procedures. In order to permit viewing of the contents of the collection chamber, the front wall 18 as shown in FIG. 1 is at least transparent at certain portions thereof which overlay the heights of the various collection compartments 28, 30, 32, 34. Also, the heights are calibrated with graduations 130 which indicate the amount of fluid collected therein. The smaller volumetric size of the first collection compartment 28 permits finer measurements, for example, from 0-200 cc of fluid while the other compartments accommodate still larger volumetric amounts. In this manner, the medical personnel can readily evaluate the performance of the chest drainage device 10 as the amount of fluid collected over time and during a complete fluid evacuation procedure by a single reading of the height of the fluid in the most recently filled collection compartment. Other portions of front wall 18 are also transparent to permit the viewing of other operational features of the device 10. In this respect, the small arm compartment 38 of the seal chamber 14 is transparent in order to permit a viewing of the height of the fluid contained within the seal chamber 14. Accordingly, the length of the small arm compartment 38 is also calibrated with gradations 40 in order to permit measurement of the height of the fluid therein. Similarly an airflow meter 48 of the type illustrated and described in U.S. Pat. No. 3,683,913 has a transparent portion 42 which permits viewing of any air bubbles passing therethrough. Grommets 44 and 46 include a central rubber portion 48 which permit injection of fluid by means of a hypodermic needle which will penetrate but not do damage the rubber seal which thereafter seals and retains the integrity of the respective chambers or portions thereof. The suction control chamber 16 includes a compartment 50 which is partially viewable through a respective transparent portion in wall 18. In order to permit visual determination of the proper level of suction setting desired, a control disk 52 is viewable through transparent portion 54 in wall 18 which indicates readily the degree of suction which is selected by means of movement of lever arm 56 extending through opening 58 of left side wall 26. An inlet port 60 is positioned in top wall 38 so that fluid and gases from a body cavity pass directly into collection compartment 12 through tubing 62. A high negativity valve 62 is positioned in top wall 22 in communication with collection chamber 12. The high negativity valve includes a button actuated valve which when depressed allows filtered air to enter the collection chamber 12. In this manner, undesired high degrees of negative pressure that may occur in the body cavity and thereby develop in the collection chamber 12 are relieved. As shown in FIG. 1, the device 10 is coupled to a suction source by means of a suitable tubing 64 that is connected over the suction inlet 66. As shown in FIG. 3, the hanger device 68 according to the present invention includes a bracket member 70 which is formed of two opposed walls 72 and 74 which have between them a post member 75 extending between walls. As shown in FIG. 3, one of the walls 72 is positioned or attached onto side wall 24 of drainage device 10. As shown more clearly in FIG. 1, the opposed walls 72 and 74 are joined together in common side wall 76 whose function will be more clearly explained hereinbelow. The hanger device 68 also includes a hook member 78 which is formed of a wire that is curved at both ends. At its upper end, the wire 78 has a greater curve so as to accommodate the larger diameter of a bedpost, for example 80. At the lower curved end, the wire 78 is hooked so as to permit the small curved end to be positioned about post member 75. The small curved end has a smallest distance of separation indicated by letter A which is less than the diameter of post member 75. The smaller curved end of wire 78 is resilient so that when the hook member is selectively rotated to the hanging position as shown in FIG. 3, the hooked small curved end can be moved away from post member 75 which is then securely advanced toward the smallest distance separation "A" whereupon the hooked end resiliently spreads apart so as to lock the hook member in the hanging position. When the hanger member is not needed to support the housing, the wire 78 can be moved so as to pull the post member 75 out of the smallest distance or separation which thereupon resiliently snaps back to its former distance of separation and thus retains the hook member about the post member 75. Thereafter, the hook member can be rotated downwardly and the wire 78 passed over and retained against a retention shoulder 78 positioned below the bracket 70 as shown in FIG. 3. Notably, the hooked end can rotate about post member 75 but is at all times retained thereabout since the common side wall 76 prevents the hooked end from separating from the post member 75. Alternatively, if common side wall 76 is not provided, the front wall 18 extends about the side walls in the manner as shown in FIG. 3 sufficiently so that if the hooked end advances past the post member 75, it will eventually engage the extended post of the front wall 18 and will not be permitted to move any farther. This once again retains the hook member relatively to the bracket member 70. Referring to FIG. 4, an alternative embodiment of the hanger device 68 according to the present invention is shown. In this alternative embodiment, a bracket member 80 includes a wall 82 which has extending therefrom a post member 84 that is attached at its other end to the side wall 24 of the housing. The wall 82 extends to the front wall 18 as shown specifically FIG. 4. The hanger device 80 also includes a hook member 86 which is formed of a wire that is curved at both ends as is the case with hook member 78. Similarly, the purposes of the hooked ends of or curved ends of hook member 86 are similar to those described previously in connection with hook member 78. However, the hook member 86 has a portion 88 which is bent so that when the hook member 86 is rotated from a stored position shown by dotted phantom lines 90 up through and to the stored position as shown by the solid lines of hook member 86 in an upright position, the bent portion 88 can rest upon the upper wall portion of wall 92 when the hook member 86 is then pressed downwardly so as to spread apart the curved end of hook member 86 about post as shown in FIG. 4A member 84 in the manner as described before with respect to hook member 78. In the embodiment illustrated in FIG. 4, there is included a hook bracket 94 which receives a wire frame 96 as shown therein. Specifically, the wire frame is as shown generally in FIG. 5 that includes an eye portion 98 that hooks and secures about a lower leg 100 of device or housing or front wall 18. The wire frame 96 supports a bag 102 which is of the type employed in automatic transfusion devices a described and illustrated in U.S. Pat. No. 4,443,220, which is incorporated herein in its entirety. The autotransfusion device includes tube 104 that is connected to the patient's cavity to be drained of fluids and also a tube which is coupled to an inlet 62 of drainage device 10. Notably the automatic transfusion device is incorporated so as to be able to return the fluid collected therein to the patient should the need arise before collecting the same within the drainage device 10. The present invention has been described in detail with particular emphasis on the preferred embodiments thereof. However, it should be understood that variations and modifications within the spirit and scope of the invention may occur to those skilled in the art to which the invention pertains.

4y

CROSS REFERENCE TO RELATED APPLICATIONS This application is a divisional of U.S. patent application Ser. No. 08/137,887, filed Oct. 15, 1993, which has issued as U.S. Pat. No. 5,451,508. Application Ser. No. 08/137,887, was a continuation of Ser. No. 07/959,529, filed Oct. 13, 1992, which application was a continuation of Ser. No. 07/463,086, filed Jan. 10, 1990. The latter two applications are abandoned. DETAILED DESCRIPTION OF THE INVENTION Vitamin 12 or cobalamin is an essential vitamin which is present in body fluids such as whole blood, plasma, serum in low concentrations (about 10 -14 mol/l) and which has a remarkably strong binding to the B12 transport proteins (the transcobalamins). Vitamin B12 deficiency which can be caused by an inadequate vitamin intake via the food, by malabsorption syndrome, by a genetically induced deficiency of one or several transcobalamins or by the presence of gut parasites such as e.g. the fish tapeworm (diphyllobothria), can manifest itself in different symptoms which depend on the age of the individual and on the duration of the vitamin B12 insufficiency. A minor vitamin B12 deficiency causes a reduction of the red blood corpuscles whereby, in addition, a series of metabolic disorders and megaloblastic anaemias occur. In children the nervous system is affected and in some cases blindness can result. At present the common methods for the determination of cobalamins, in particular of cyanocobalamin (vitamin B12) in very dilute aqueous solutions (such as e.g. the blood serum) are based on methods using radioactive labels in which intrinsic factor (IF) is used as the binding reagent. The common techniques use 57 Co-B12 as the marker and are based on a competitive principle in which free and labelled analytes compete for binding to the IF. The separation of bound and free analyte (bound/free separation) is then effected by methods such as e.g. the use of active charcoal, IF bound to a solid phase or by magnetic separation in which IF is bound to paramagnetic particles (c.f. Brit. J. Haemat. 22 (1972) 21-31, Clin. Chem. 24 (1978) 460-466, Clin. Biochemistry 18 (1985) 261-266). Before the determination of vitamin B12 in body fluids it is necessary to detach vitamin B12 from its binding proteins present in blood. This is carried out by heat treatment or by destruction of the binding proteins in the alkaline range (pH >13.5) under the action of the thiol, dithiothreitol (DTT), which cleaves SH bonds (incubation of the serum sample with DTT in the alkaline range). This destruction can be intensified by adding organic substances e.g. acetone or by adding competitive cross-reactive species e.g. cobinamide. In the determination it is advantageous to add alkali cyanide to increase the extractability of vitamin B12 and to convert the cobalamins into a stable and detectable form i.e. cyanocobalamin. The disadvantages of the known methods for the determination of vitamin B12 are in particular due to the use of intrinsic factor. Thus false results are observed when the intrinsic factor used is not sufficiently pure (max. 5% impurity by other B12 binding proteins). Numerous samples apparently contain antibodies to IF which block the ability to bind radioactively labelled B12. This can simulate vitamin B12 values which are too low. The object of the present invention was therefore to provide a method for the determination of vitamin B12 which does not require the use of intrinsic factor and which thus avoids the previously mentioned disadvantages and which enables an exact determination of B12 in serum in a rapid, simple and reproducible manner. The object of the invention is therefore a method for the determination of vitamin B12 by incubation of a sample solution with at least two receptors R 1 and R 2 , of which R 1 mediates the binding to the solid phase and R 2 is labelled, separation of the two phases and measurement of the label in one of the two phases, which is characterized in that a receptor is used as one of the receptors R 1 or R 2 which contains a monoclonal antibody capable of specific binding to B12 that has an affinity constant of at least 5×10 9 l/mol, and a receptor is used as the other receptor R 1 or R 2 which contains B12 or an analogue thereof. The method according to the present invention represents a decisive advance for clinical diagnosis, since the determination of vitamin B12 was one of the last parameters for which no immunological test using immobilized monoclonal antibodies was commercially available. In principle all current immunoassays such as radio-immunoassay, enzyme-immunoassay, fluorescence-immunoassay etc. are suitable for the immunological method of determination according to the present invention. In addition, all variants of the procedures such as competitive immunoassay, IEMA method etc. are applicable. A competitive enzyme-immunoassay or a method according to the IEMA principle has proven to be particularly expedient for the determination of vitamin B12. In the competitive enzyme-immunoassay the B12 to be determined competes with a known amount of labelled B12 for the binding sites of the carrier-bound monoclonal antibody. The test procedure can also be carried out such that the B12 to be determined and carrier-bound B12 compete for a limited number of binding sites on the monoclonal antibody. The portion of labelled monoclonal antibody bound to the B12 fixed to the carrier is determined from the label. These variants can also be modified such that the monoclonal antibodies are used in an unlabelled form. The portion of antibody bound to the B12 fixed to the carrier is then determined by incubating with an antibody directed towards the Fc part of the antibody and determining the portion of bound label. In the IEMA method labelled monoclonal antibody is added in excess. The excess labelled antibody which is not bound to B12 is removed from the solution using a hapten-carrier matrix. The different variants of these test methods, as well as details for carrying out these procedures are described in full in the literature. Other immunological methods for the immunological determination of haptens are, however, also feasible for the determination of B12 using the antibodies according to the present invention as described for example in the German Patent Applications DE-P 38 34 766 or DE-P 38 22 750. According to the present invention at least one monoclonal antibody is used which is directed specifically towards vitamin B12 and which has an affinity constant of >5×10 9 l/mol, preferably larger than 10 10 l/mol and particularly preferably larger than 5×10 10 l/mol, as well as a cross-reactivity with methylcobalamin and cyanocobalamin of 100%; with cobinamide of <0.05%; with purinylcobinamide of 1.1%; with cobyrinic acid-diamide of <0.05%; with 2-hydroxy-5,6-dimethylbenzimidazolyl-cobamide of 1.5% and with (carboxy(2-cyanamino-4,5-dimethylphenyl)-amino)-cobamide of 0.07%. The monoclonal antibodies can be used as complete antibodies, chimeric antibodies or bivalent antibody fragments. Therefore, for the determination of vitamin B12, the sample solution is incubated with at least two receptors R 1 and R 2 . In this process receptor R 1 mediates the binding to the solid phase. For this receptor R 1 can either be directly bound to the solid phase or via a spacer, or else it can be present in a soluble form and not be immobilized until after the immunological reaction has been carried out. Receptor R 1 contains either a monoclonal antibody capable of specific binding to or vitamin B12 or an analogue thereof. The binding of the antibody or of B12 to the carrier (immobilization) is carried out according to methods familiar to the expert by adsorptive or chemical binding or by binding by a specific binding pair. In these cases one partner of the binding pair is immobilized, while the other partner is bound chemically to B12 or the antibody. The antibody or B12 can then be immobilized either before or during the immunological determination reaction by means of this binding pair. Examples of such binding pairs are biotin-streptavidin/avidin, hapten-antibody, antigen-antibody, concanavalin-antibody, sugar-lectin, hapten-binding protein. Materials such as e.g. tubes, microtitre plates, beads or microcarriers made of plastics such as polystyrene, vinylpolymers, polypropylene, polycarbonate, polysaccharides, silicones, rubber or also treated glass (cf. e.g. E. T. Maggio, "Enzyme Immunoassay" CAC Press, Florida, 1980, in particular pages 175 to 178; EP-A-063 064; Bioengineering 16 (1974), 997-1003; C. J. Sanderson and D. V. Wilson, Immunology 20 (1971), 1061-1065) can be used as carrier materials for the immobilization of the antibody according to the present invention or for the immobilization of B12. In particular, a carrier material coated with avidin or streptavidin, in particular polystyrene, is used as the carrier material and is preferably prepared as described in EP-A 0 269 092. Receptor R 2 also contains either vitamin B12 or an analogue thereof or a monoclonal antibody capable of specific binding to vitamin B12 and is labelled. The usual agents for the respective methods of determination are suitable for the labelling. Thus radioisotopes, for example 57 Co, are used for the labelling in a radio-immunoassay. For an enzyme-immunoassay, all enzymes which are usually used, for example peroxidase or β-galactosidase are suitable. For a fluorescence-immunoassay the usual fluorescent groups can be used as the marker. Details of these different test methods and variants of the procedures are known to the expert. The binding of the label to B12 or to the antibody can be carried out via a specific binding pair in an analogous manner to the binding to the solid phase. The binding of the antibody or of B12 to one of the above-mentioned binding partners is carried out by methods familiar to the expert such as via carbodiimide and hydroxysuccinimide. When labelling B12 with an enzyme, a B12 conjugate is preferably used of the formula (I) B12--CO--NH--(--NH--R--CO--NH--).sub.x --N═GP (I) wherein B12 denotes the residue formed by cleavage of a --CONH 2 group from cyanocobalamin (vitamin B12) and R denotes a spacer, x is 0 or 1 and GP represents a marker enzyme residue containing glycosyl groups which is bound via a glycosyl residue to the --NH--N═ group. In the formula (I) the --CONH-- group is preferably at the d-position of the B12 residue and B12--d--CO--NH--N═GP and in particular B12--d--CO--NH--NH--CO--CH 2 --(--O--CH 2 --H 2 --) 3 --O--CH 2 --CO--NH--N═GP are primarily used. Peroxidase (POD) is preferably used as the enzyme marker (GP). The B12 conjugates of the formula (I) are an object of the German Patent Application P 3900648.4 (Title: New cobalamin-acid hydrazides and cobalamin derivatives derived therefrom) by the same applicant and with the same date of application. They can be prepared by coupling (condensation) of cobalamin acid-hydrazides of the formula B12--CO--NH--NH--(--R--CO--NH--NH--).sub.x --H (in which B12, R and x have the meaning mentioned above), which are also an object of the above-mentioned German Patent Application P 3900648.4 which was applied for at the same time, with the OH groups of glycosyl residues of glycoproteins after they had been oxidized and the hydrazone group --NH--N═CH-glycoprotein has formed under conditions which are well-known. In a preferred embodiment of the method according to the present invention the sample solution is prepared in the usual way in order to detach the vitamin B12 whereby the binding proteins are destroyed by addition of a thiol, dithiothreitol (DTT), in the alkaline range (pH>13.5) which can cleave SH groups or else by boiling for 30-60 minutes and subsequent centrifugation. In the method according to the present invention for the determination of vitamin B12 the sample preparation (cleavage of the binding protein) is preferably carried out with lipoic acid (LA) or a homologue thereof of the formula (II) ##STR1## wherein n denotes I to 8 and in particular 3 to 5, whereby lipoic acid (formula II, n=4) is particularly preferred. This method is an object of the German Patent Application P 3900649.2 (Title: Method for detaching an analyte from its binding protein) by the same applicant and with the same date of application. According to this method the incubation of the sample at room temperature in the alkaline range (pH value 10 to 14; preferably using sodium hydroxide as the alkaline medium at a concentration of 0.05 to 1 mmol/l) can be carried out in less than 15 minutes. In this process, the acid having the formula (II) (calculated for lipoic acid with n=4) is used preferably in a range of 1 to 20 mg/ml and in particular in the range of 4 to 10 mg/ml. The method according to the present invention yields very exact and reproducible values which is in particular due to the fact that a monoclonal antibody to vitamin B12 is used which has a very high affinity constant for vitamin B12. These antibodies are also an object of the invention. Such specific monoclonal antibodies with such high affinity constants have not been known up to now. A further object of the invention is a method for the production of a monoclonal antibody capable of specific binding to B12 wherein inbred mice are immunized with vitamin B12-d-acid to which an immunogenic carrier material is coupled via a spacer, in particular 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, B-lymphocytes are isolated from the immunized animals and fused with myeloma cells using transforming agents, the hybrid cells which form are cloned and cultured and the monoclonal antibodies are isolated from these cells. For the isolation of the monoclonal antibodies according to the present invention, B12 is first linked to an immunogenic carrier material. All materials usually used for this purpose, for example, albumins such as bovine serum albumin, edestin etc. are suitable as immunogenic carrier materials. The linkage of B12 to the carrier material is carried out according to well-known methods. Subsequently, experimental animals, for example mice, are immunized with the immunogenic conjugate. For the immunization the immunogen is, for example, administered with the adjuvant in the usual manner. Complete or incomplete Freund's adjuvant is preferably used as the adjuvant. The immunization is carried out over many months with at least four immunizations at intervals of four to six weeks (intraperitoneal injection). B-lymphocytes are isolated from the animals which have been immunized in this way and they are fused with a permanent myeloma cell line. The fusion is carried out according to the well-known method of Kohler and Milstein (Nature 256, 1975, pages 495 to 497). The primary cultures which form during this process are cloned in the usual manner e.g. using a commercial cell sorter or by "limiting dilution". Those cultures are processed further which are positive towards B12 and show the above-mentioned cross-reactivity in a suitable test procedure such as an enzyme-immunoassay (ELISA method). In this way several hybridoma cell lines are obtained which produce the monoclonal antibodies according to the present invention. These cell lines can be cultured and the monoclonal antibodies produced by them can be isolated according to well-known methods. In this way the antibodies used according to the present invention can be obtained, and in particular antibodies with an affinity constant of >5×10 9 l/mol, preferably larger than 10 10 l/mol and particularly preferably larger than 5×10 10 l/mol, as well as with a cross-reactivity with methylcobalamin and cyanocobalamin of 100%; with cobinamide of <0.05%; with purinylcobinamide of 1.1%; with cobyrinic acid-diamide of <0.05%; with 2-hydroxy-5,6-dimethylbenzimidazolyl-cobamide of 1.5% and with (carboxy (2-cyanamino-4,5-dimethylphenyl)-amino)-cobamide of 0.07%. Antibodies which have such a high specificity are produced for example by the cell lines ECACC 88101301 and ECACC 88101302. The cell lines are deposited at the repository ECACC (European Collection of Animal Cell Cultures, Porton Down, GB) under the respective number quoted. The monoclonal antibodies isolated in this way are distinguished by a very high affinity (affinity constant larger than 5×10 -9 ) for B12 and the previously mentioned cross-reactivities. The affinity of the monoclonal antibody is preferably above 10 10 l/mol and particularly preferably above 5×10 10 l/mol. The monoclonal antibodies according to the present invention are excellently suitable for the specific determination of B12 in a sample, for example serum or plasma. For these methods of determination, the monoclonal antibodies can be used as such or as chimeric antibodies or fragments thereof which have the corresponding immunological properties, for example Fab fragments. Thus the term "monoclonal antibody" is understood to denote complete antibodies as well as the fragments. The following Examples are intended to elucidate the invention in more detail without being limited by them. Room temperature (RT) is understood as a temperature of 25° C. ±2° C. The quoted percentages refer to percentage by weight. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 represents a standard curve for a determination of vitamin B12 according to Example 4 with different monoclonal antibody concentrations. Curve 1 represents 85 ng/ml monoclonal antibody; curve 2 shows 90 ng/ml monoclonal antibody; curve 3 shows 95 ng/ml monoclonal antibody; and curve 4 shows 100 ng/ml monoclonal antibody. FIG. 2 represents a comparison of a determination according to Example 4 (monoclonal antibody of the invention) (curve 2) with a determination using a polyclonal antibody (curve 1). FIG. 2 indicates that a considerably steeper calibraion curve is obtained with monoclonal antibodies in accordance with the instant invention as compared to polyclonal antibodies. FIG. 1 shows a standard curve for a determination of vitamin B12 according to Example 4 with different MAB concentrations: Curve 1: 85 ng/ml MAB curve 2: 90 ng/ml MAB curve 3: 95 ng/ml MAB Curve 4: 100 ng/ml MAB. FIG. 2 shows a comparison of a determination according to Example 4 (curve 2) with a determination using a polyclonal antibody (curve 1). EXAMPLE 1 Preparation of monoclonal antibodies to vitamin B12 Preparation of the immunogen Vitamin B12-d-acid (prepared according to JACS 102 (1980) 2215) is coupled to edestin via 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC). Immunization of mice with vitamin B12 conjugate Balb/c mice, 8 to 12 weeks old, were initially immunized intraperitoneally with 100 μg immunogen in complete Freund's adjuvant. After six weeeks, three further immunizations were carried out at intervals of 4 weeks in which 100 μg immunogen in incomplete Freund's adjuvant was administered intraperitoneally. The immunization was repeated in vitro with 100 μg immunogen 4 days, 3 days and 2 days before the fusion. Fusion Spleen cells from an immunized mouse were mixed with P3x63Ag8-653 myeloma cells (ATCC-CRL 8375) in a ratio of 1:5 and centrifuged (10 minutes, 300 g, 4° C.). The cells were washed once again with BSS (balanced salt solution) buffer and centrifuged at 400 g in a 50 ml conicle tube. The supernatant was discarded, the cell sediment was loosened, 1 ml PEG (MG 4000, Merck) was added and piperted through. After one minute in a water-bath 5 ml RPMI 1640 medium (RPMI=Rosewell Parker Memory Institute) without FCS (fetal calf serum) was added dropwise over a period of 4 to 5 minutes, mixed, filled up to 50 ml with medium and subsequently centrifuged for 10 minutes at 400 g and 4° C. The sedimented cells were taken up in RPMI 1640 medium+10% FCS and 5×10 4 to 1×10 5 spleen cells or 5×10 4 peritoneal exudate cells were added as "feeder cells". Hypoxanthine-azaserine selection medium (100 mmol/l hypoxanthine, 1 μg/ml azaserine) was added on the next day. About 7 to 10 days after the fusion, many clones were already visible. The supernatant of the primary cultures was tested according to an ELISA method described in Example 2. Primary cultures which showed the desired cross-reaction were cloned using FACS (fluorescence activated cell sorter) in 96-well cell culture plates. 1×10 4 peritoneal exudate cells or 2×10 4 spleen cells were added per well as "feeder cells". In this manner the two hybridoma cell lines ECACC 88101301 and ECACC 88101302 could for example be isolated and have been deposited at the repository ECACC under the cited respective repository numbers. The abbreviation ECACC stands for the European Collection of Animal Cell Cultures, PHLS Centre for Applied Microbiology and Research, Porton Down, Salisbury SP40JG Wiltshire England. Induction of Ascites 5×10 6 hybrid cells were injected i.p. once or twice in mice pre-treated with 0.5 ml Pristan. Ascites could be collected 1 to 3 weeks afterwards with an IgG concentration of 5 to 20 mg/ml. The antibodies can be isolated from this in the usual way. These monoclonal antibodies are directed specifically towards vitamin B12 and have the desired cross-reactivity. The monoclonal antibodies are denoted MAB 1 (from ECACC 88101301) or MAB 2 (from ECACC 88101302). EXAMPLE 2 Screening test for antibodies to vitamin B12 The principle of the test used to detect the presence and specificity of antibodies to vitamin B12 in the serum of immunized mice or in the culture supernatant of the hybrid cells or in ascites is an ELISA method: microtitre plates are coated with 1 μg/ml B12 conjugate (B12-d-acid coupled to bovine serum albumin via EDC) and coating buffer (0.2 mol/1 sodium carbonate/sodium bicarbonate, pH 9.3 to 9.5) at 37° C. for one hour. The plates are re-treated for 10 minutes with 0.9% sodium chloride solution and 1% albumin solution. Subsequently they are washed with 0.9% sodium chloride solution. Afterwards they are incubated at 37° C. for one hour with 100 μl sample and washed again with 0.9% sodium chloride solution. In order to test the cross-reaction 50, 500 and 5000 μg/ml of the vitamin B12 derivative to be tested is added to the sample solution. A reduction of the measured signal in the presence of the derivative indicates a cross-reaction. A further incubation follows (1 hour, 37° C.) with 450 U/ml of a sheep-Fab-anti-mouse Fc α-peroxidase conjugate. After washing once again with 0.9 % sodium chloride the peroxidase activity is determined in the usual way (for example with 2,2'azino-di-[3-ethylbenzthiazoline sulphonate (6)](ABT®, 30 minutes at room temperature, the difference in absorbance ΔmA is read at 422 nm). EXAMPLE 3 Determination of the cross-reaction The test is carried out as described in Example 2. The antigen to be tested for cross-reaction is added in increasing concentrations (50 μg/ml, 500 μg/ml, 5000 μg/ml) to the monoclonal antibody. Afterwards the cross-reaction is calculated from the following formula: ##EQU1## C=concentration of the antigen required to attain 50% of the max. signal. The determined values which are identical for the monoclonal antibody MAB 1 and MAB 2 are summarized in the following Table. ______________________________________cross-reacting antigen cross-reaction______________________________________Methylcobalamin 100Cyanocobalanin 100Cobinamide <0.05Purinylcobinamide 1.1Cobyrinic acid-diamide <0.052-hydroxy-5,6-dimethyl- 1.5benzimidazolylcobamide(Carboxy(2-cyanamino-4,5- 0.07dimethylphenyl)aminocobamide______________________________________ EXAMPLE 4 Determination of vitamin B12 a) Sample preparation 250 μl human serum are mixed with 125 μl releasing agent (consisting of 8 mg/ml lipoic acid, 1 mg/ml potassium cyanide, dissolved in 0.5 mol/l NaOH) and incubated for 15 minutes at room temperature. Afterwards 125 μl 200 mmol/l phosphate buffer, pH 4.1 is added. b) Reagents: Polystyrene tubes coated with thermo-BSA streptavidin (prepared according to EP-A 0269092) Reagent 1 95 ng/ml biotinylated MAB 1 or MAB 2 (biotinylation according to JACS 100 (1978) 3585 to 3590) 40 mmol/l phosphate buffer, pH 7.2 Reagent 2 B12--d--CO--NH--NH--CO--CH 2 --(--O--CH 2 --CH 2 --) 3 --O--CH 2 --CO--NH--N═POD) (activity about 60 mU/ml) 40 mmol/l phosphate buffer, pH 7.2 Reagent 3 100 mmol/l phosphate-citrate buffer, pH 4.4 1.9 mmol/l ABTS® 3.2 mmol/l sodium perborate c) Procedure for the determination To carry out the determination 200 μl pre-treated sample and 800 μl Reagent 1 are added to a streptavidin tube and incubated for 60 minutes at room temperature. Afterwards it is washed with wash solution and 1000 μl Reagent 2 is added and incubated for 30 minutes at room temperature. It is washed with wash solution and 1000 μl Reagent 3is added, incubated for 30 minutes at room temperature and the colour formed is measured at 422 nm as a measure of the vitamin B12 content. d) Analogous results are obtained when instead of biotinylated complete MAB 1, biotinylated Fab fragments are used. Fab fragments are prepared as follows: MAB 1 is cleaved with papain as described in Biochem. J. 73 (1959) 119 to 126. The Fab fragments which form in this process are separated by means of gel filtration on Sephadex G 100 and ion-exchange chromatography on DEAE cellulose according to Meth. in Enzymology 73 (1981) 418 to 459. EXAMPLE 5 Comparison with a well-known radioimmunoassay for B12 Cyanocobalamin in 40 mmol/l phosphate buffer, pH 7.2 containing 0.9% sodium chloride, 0.9% crotein C and 0.1% potassium cyanide is used as standard. As a comparison, the test marketed by Becton Dickinson (simultaneous no boil SNB-B12/folate-radioassay) was used. In this test immobilized intrinsic factor and radioactively labelled B12 ( 57 Co B12) is used. Dithiothreitol (DTT) in alkaline solution is used in this test for the preparation of the samples. The correlation between this radioimmunoassay and the method according to the present invention is >0.98 in the vitamin B12 concentration range between 100 and 400 pg/ml. EXAMPLE 6 Vitamin B12 determination with polyclonal antibody to B12 (comparative example) a) Collection of the antiserum 10 sheep are immunized with the immunogen described in Example 1 (0.5 ng/ml in complete Freund's adjuvant) at intervals of four weeks over 6 months. Afterwards the antiserum is collected and purified by affinity chromatography. b) Preparation of biotinylated Fab fragments of the polyclonal antibody to B12 (Fab-biotin) The polyclonal antibodies are cleaved with papain as described in Biochem. J. 73 (1959) 119-126. The fragments which form in this process are separated by means of gel filtration on Sephadex G 100 and ion-exchange chromatography on DEAE cellulose according to Meth. in Enzymology 73 (1981) 418 to 459. The biotinylation is carried out as described in JACS 100 (1978) 3585-3590. c) Procedure for the determination The determination is carried out as described in Example 4 whereby 95 ng/ml Fab-biotin is used instead of 95 ng/ml biotinylated MAB 1.

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to a regulator spool valve controlled by a direct acting solenoid with a multiplex latch valve and located in a machined main control casting of an automatic transmission. 2. Description of the Prior Art An automatic transmission includes a hydraulic system for regulating fluid pressure and hydraulic fluid flow in various lines connected to components of the transmission. The system includes a regulator spool valve packaged in a main control casting, which is machined at a transmission production plant. The casting, preferably of an aluminum alloy, is usually referred to as a valve body. The components of the system are assembled in the valve body and have transfer functions characterized at the plant. A solenoid-actuated regulator valve controls pressure communicated from the valve to a clutch or brake whose state of engagement and disengagement determines the gear in which the transmission operates. Transmissions clutch regulators require a method to provide hydraulic pressure to clutches and brakes for high torque operating conditions such that the required pressure can be delivered independently of the control pressure range suitable for shift control. The separation of static capacity (high torque) and dynamic control pressure ranges is accomplished through use of latch valves. The typical latch valve acts to override the regulation of the clutch regulator by exhausting the feedback pressure at the spool. This causes the spool to no longer be in force equilibrium, resulting in spool traveling to its limit opening full communication between supply and control pressure ports. The exhaust of the feedback port and subsequent valve travel result in significant delay and undershoot in clutch control pressure on transition back to dynamic pressure control state. A need exists in the industry for a latch valve formed in a valve body and operating with a regulating valve such that shift control of a transmission control element can be separated from the high pressure that is used to produce the high torque transmitting capacity of the control element when the element is engaged, which will eliminate deficiencies associated with altering regulator feedback pressure, and can be used in conjunction with self-contained devices such as direct acting solenoids. SUMMARY OF THE INVENTION A latch valve includes a first port for containing line pressure, a second port for containing control pressure, a third port located between the first and second ports, alternately connecting the first and second ports to a transmission control element, and a fourth port for containing control pressure that tends to close the second port and open the first port in opposition to a spring force. A method for operating the latch valve includes supplying line pressure to a first port, supplying control pressure to a second port, alternately connecting the first and second ports to a transmission control element through a third port located between the first and second ports, controlling the valve using control pressure tending to close the second port and open the first port in opposition to a spring force, and latching the valve when the first port opens and the second port closes. A multiplexing latch valve that can continue to move throughout the pressure range of the regulator valve doubles as a compliance source to stabilize the regulator valve when the transmission control element is not connected to the regulator valve. This combination maintains the regulator valve in a pressurized state with normal feedback even when the control element is latched to line pressure. The latch valve is actuated by regulator control pressure to selectively connect either regulator control pressure or line pressure to the control element. The multiplexing architecture can be applied to either a variable bleed solenoid (VBS) regulator valve paired systems or to direct acting solenoid systems. For the direct acting solenoid system, latch occurs without the addition of another solenoid, either to supplement the force of the primary solenoid coil or as an On-Off control of a similar multiplexing latch valve. The latch valve provides circuit compliance to stabilize the regulator valve after it is disconnected from the clutch, thereby eliminating need for a separate accumulator part. The scope of applicability of the preferred embodiment will become apparent from the following detailed description, claims and drawings. It should be understood, that the description and specific examples, although indicating preferred embodiments of the invention, are given by way of illustration only. Various changes and modifications to the described embodiments and examples will become apparent to those skilled in the art. DESCRIPTION OF THE DRAWINGS The invention will be more readily understood by reference to the following description, taken with the accompanying drawings, in which: FIG. 1 is a cross section of a casting-integrated direct acting regulating solenoid valve and a latch valve; FIG. 2 is a cross section of a modification of the valve of FIG. 1 with the spool removed from the valve chamber; FIG. 3 is a cross section of a casting-integrated direct acting regulating solenoid valve showing the spool located in the valve chamber; FIG. 4 is a graph of control element pressure and solenoid current during engagement of the control element; and FIG. 5 includes graphs of delatch pressure and regulating spool position while the latch valve is delatched. DESCRIPTION OF THE PREFERRED EMBODIMENT The casting-integrated, direct acting solenoid hydraulic valve 10 shown in FIGS. 1 and 2 includes a valve body 12 formed of cast metal, preferably an aluminum alloy. The valve body 12 contains a valve spool 14 , formed with lands 16 - 19 ; a compression spring 20 urging the spool rightward; an adapter 22 ; an armature pin 24 extending through the adapter and contacting the spool; an electromagnetic solenoid 26 , which actuates the pin to move leftward when the solenoid is energized and allows the spool to move rightward when the solenoid is deenergized; and a second compression spring 28 for maintaining the pin in contact with the spool. Preferably spring 20 has a relatively low spring constant so that control pressure produced by valve 10 is substantially zero when no electric current is supplied to energize the solenoid 26 . The valve body 12 is formed with control ports 30 , 42 through which control pressure communicates with the chamber 32 containing the spool 14 ; a line pressure port 34 , through which line pressure communicates with the chamber; sump port 36 , through which hydraulic fluid flows from the chamber to a low pressure sump; and a exhaust ports 38 , 40 , through which the chamber 32 communicates with a low pressure exhaust. Adapter 22 is continually held in contact with an installation datum or reference surface 46 formed in sump port 34 by the elastic force produced by a resilient clip 44 , which is secured to the outer surface of a housing 45 that encloses the solenoid 26 . In operation, valve 10 regulates control pressure in port 30 and feedback pressure in port 42 by producing a first sum of the force of spring 20 and the rightward net force due to control pressure in port 42 acting on the differential areas of lands 16 and 17 . Balancing the first sum of forces is a second sum of leftward forces comprising the force of the solenoid-actuated pin 24 and the force of spring 28 . As the force of pin 24 increases, valve 10 opens a connection through metering edge 49 between line pressure in port 34 and control pressure in ports 30 , 42 . As metering edge 49 open, control pressure increases. When control pressure increases sufficiently for the current position of pin 24 , the differential feedback control pressure on lands 16 , 17 causes the metering edge 49 to close and metering edge 48 to open a connection between control pressure port 30 and to the low pressure exhaust through chamber 32 , exhaust port 38 and passage 72 . A single flycutting tool concurrently machines both of the metering edges 48 , 49 and the installation datum or reference surface 46 in the valve body. The solenoid module 50 includes adapter 22 , solenoid 26 , housing 45 and spring 28 . All edges that requiring precise relative positions are cut in a single operation for improved tolerances and manufacturing efficiency. Metering edges are precision machined rather than cast for improved edge quality, location accuracy, and zero draft. High precision tolerances enable close control of leakage and pressure regulation accuracy. Close tolerances enable flow control with a short stroke magnetic section 50 . A single metering control pressure port 30 at spool land 18 (Meter Out-Meter In, as shown in FIG. 1 ) or dual metering control pressure ports 30 , 38 at control land 52 (Meter Out-Meter Out, as shown FIG. 3 ) can be accommodated with no change in tolerances. A clear division of tolerance responsibility is established for the two manufacturing groups. The valves shown in FIGS. 1-3 enable standard main control (multi-bore including worm trail) configurations while providing magnet interface tolerances. A control pressure bleed port 38 provides for spool position control and stability. Tracking response is improved with no dead-zone to cross. Low frequency hunting across the dead-zone is also prevented. Tight machining tolerances allow for minimized overlap reducing dead band. In FIG. 2 the diameter of control land 17 is larger than the diameter of land 16 of valve 10 ′. The large diameter land 16 of valve 10 ′ defines a large diameter spool end damper 60 for enhancing stability, permitting use of a relatively large diameter, contamination resistant damper port 62 . Damper 60 is formed outside of the feedback path 64 for minimum feedback lag and improved stability. The diameter of damper 60 is large relative to the difference in diameter of the lands 16 and 17 . The large diameter of spool land 16 and damper 60 combined with flow notches enables high flow with short stroke magnet as well as fly cut manufacturing technique. The axial surface 68 of adapter 22 is located in chamber 32 due to contact with reference surface 46 such that, when solenoid 26 is deenergized and spool 14 moves rightward in the chamber, land 19 contacts surface 68 before the armature pin 24 contacts a stop surface 70 in the solenoid module, thereby preventing spring 28 from becoming fully compressed due to contacts among its coils. In this way, the spool end feature provides positive stop for forced over travel protection of the solenoid module 50 . Damping chamber 60 is provided with an oil reservoir using an elevated vent 66 and fed from the control pressure bleed port 42 . The casting-integrated, direct acting solenoid hydraulic valves 10 , 10 ″ each includes a latch valve 80 formed in the valve body 12 of cast metal. Valve 80 includes a spool 82 , formed with lands 84 , 86 ; a compression spring 87 urging spool 82 rightward; exhaust port 88 ; line port 90 , connected to a source of line pressure whose magnitude is substantially constant; an outlet port 92 , through which a clutch or brake 94 of the transmission is actuated; a control port 96 communicating through passage 64 with control pressure ports 30 , 42 of regulator valve 10 ; and a control pressure feedback port 98 also communicating through passage 64 with control pressure ports 30 , 42 of regulator valve 10 . In operation, valve 80 supplies actuating pressure through line 100 to the cylinder 102 of a hydraulic servo that actuate the transmission control element 94 . When control pressure generated force is lower than spring installed load, spring 87 forces spool 82 to the right-hand end of the chamber, thereby closing line port 90 , opening control port 96 and communicating fluid at control pressure to the control element 94 through outlet port 92 and line 100 . As control pressure increases, spool 82 moves axially leftward along the valve chamber due to a force produced by control pressure in feedback port 98 acting in opposition to the force of spring 87 . After the clutch is fully engaged and control pressure increases further land 86 gradually closes port 96 , and land 84 maintains line port 90 closed. As control pressure increases further, land 86 closes control port 96 , and land 84 opens a connection between line port 90 and output port 92 , thereby bypassing valve 80 and pressurizing control element 94 using line pressure, which is based on static capacity of applied clutches. If control pressure increases further after valve 80 is latched, line pressure alone is applied to fully engage the control element 94 . The spool 14 of regulating valve 10 is maintained in its regulating position while valve 80 is latched. Valve 80 is delatched by reducing control pressure, which causes land 84 to close line port 90 , and land 86 to reopen a connection between control port 96 and the transmission control element 94 through outlet port 92 and line 100 . FIG. 4 shows the variation of outlet pressure in port 92 in response to current in solenoid 26 . The first portion of the relation occurs as control pressure is increased while control port 96 is connected to outlet port 92 and line port is closed. The second portion 106 occurs after point 108 where control port 96 closes and constant line pressure through port 90 opens to outlet port 92 bringing the control element to full capacity at 110 . The two portions allow for increased pressure to current resolution (reduced gain) while maintaining overall achievable pressure range, as seen when compared variation of system without latch feature. The feedback chamber 102 of valve 80 is not exhausted when valve 80 is latched, thereby eliminating the possibility of entrapping air in the lines feeding control element 94 . Because the feedback chamber 102 of valve 80 is not exhausted when valve 80 is latched, those lines need not be refilled when valve 80 is delatched. The regulator valve 10 and latch valve 80 in combination provide functional advantages in transition states of clutch control by performing the latch transition while maintaining regulation control. As FIG. 5 shows, upon delatching valve 80 , the position 112 of spool 14 of the regulator valve 10 remains in a control metering position because its spool was regulating to the deadheaded circuit 96 and compliance volume 98 while latched and provides superior transition when switched to regulating to the line 100 and control element 94 compared to a VBS-regulator-latch valve system 114 . A VBS-regulator-latch system commonly experiences pressure undershoots 116 past the desired delatch pressure 118 , whereas the delatch pressure transient 120 produced by the combination of valves 10 , 80 closely tracks the desired delatch pressure 118 with virtually no undershoot. The latch valve is applicable to both VBS/VFS actuated spool valves and direct acting solenoid controlled systems. In accordance with the provisions of the patent statutes, the preferred embodiment has been described. However, it should be noted that the alternate embodiments can be practiced otherwise than as specifically illustrated and described.

4y

BACKGROUND OF THE INVENTION The present invention relates to a process for digesting garbage or garbage contained wastes, particularly to a microbiological treatment which facilitates the treatment with high efficiency and economics. Although presently garbage and garbage contained wastes are being incinerated or reused for land reclamation, they are causing various secondary pollution troubles, as it is well known. In this regard, such organic wastes as excess activated sludge and human wastes have so far been treated by an anaerobic digestive method. Recently, however, there is an indication that even garbage contained wastes are to be treated by an anaerobic digestive method. This anaerobic digestive method possesses such advantages as that it enables a reuse of the by-product methane gas as energy for operating the digestion facilities, and that it enables an effective use of digested sludge as a useful organic fertilizer. On the other hand, as a mechanism of anaerobic digestion, mainly two reactions are known. Namely, one is a liquefaction reaction wherein such volatile fatty acids as acetic acid, propionic acid and n-butyric acid are obtained by turning the organics involved in waste water into low molecular weight substance through the action of anaerobic liquefaction bacteria (septic bacteria), and the other is a reaction wherein these fatty acids thus produced are converted into methane by the action of gasification bacteria (methane bacteria). Thereagain, the usually exercised anaerobic digestion follows a process wherein the treatment is performed under a coexistent state of these two bacteria groups in the same tank for an extended period of time as long as 30 to 50 days. On account of this, in spite of such aforementioned non-polluting and energy-saving characteristic features, its actual application has been declining in number from year to year, to the extent where it is presently employed only for treating human wastes a few other purposes. Quite recently, its aforementioned advantageous points are being re-evaluated, and studies are progressing in the U.S.A. and some other countries, in order to improve its low treatment efficiency which is the primary drawback of the process. Lately, it has been evidenced that the above two reactions can be separated from each other, and it is possible to shorten the treatment period significantly from that of the conventional parallel-dual fermentation by optimizing each of these two reactions. Incidentally, however, under the aforementioned two-step treatment process, the liquefaction reaction at the first step proceeds within a state of a weak acidic to neutral pH, but, because of the conversion of organic substances into volatile fatty acids in the course of the treatment process, it necessitates an amount of alkali, as a neutralizer, almost equivalent to the volume of organic acid generated. Any use of neutralizer in the course of the liquefaction process results in a lower separability of digested sludge and separated water at the final step. Moreover, if garbage is treated at the liquefaction process of the first step, sometimes it generates hydrogen gas in addition to carbon dioxide, and the volume of the generated hydrogen gas, in some cases, reaches 0.1 m 3 per each kg of the charged organics. If the hydrogen gas is generated at the liquefaction process of the first step, much chemical energy would be lost at the liquefaction process, and it naturally affects the methane yield at the gasification of the second step. SUMMARY OF THE INVENTION The purpose of the present invention is to eliminate the aforementioned defects of the conventional technique and to make available a highly efficient and economic treatment process. Furthermore, the characteristic feature of the present invention is to use alcohol fermentation, as described hereunder, which is to be exercised in lieu of the liquefaction process of the aforementioned two-step liquefaction treatment method; that is, to convert the fermentable carbohydrate into ethanol by alcohol fermentative yeast in the liquid state, without sterilizing organic wastes, and, next, to recover methane gas by treating the fermented product which contains ethanol directly with methane bacteria. In this manner, the fermentable carbohydrate contained in garbage can be turned with a better yield into an energy source of methane bacteria and carbon source. This process avoids a voluminous generation of hydrogen gas as was encountered in the conventional liquefaction process (acidic fermentation) and also permits the reduction of the required volume of neutralizer down to 10-20% of the conventional process. Further, in exercising the aforementioned alcohol fermentation treatment, it is preferable to exercise it under a co-existent state with amylase producing yeasts, lipase producing yeasts and protease producing yeasts in addition to alcohol fermentative yeasts; that is, simultaneously to further lower the molecular weight of undecomposed starch contained in garbage in order to accelerate the activity of the alcohol fermentative yeast, and to change the ingredients into a state which facilitates the activity of gasification bacteria which come into action at the next step, by turning the ingredients of fat, protein, etc. effectively into low molecular weight substances. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is the flow-sheet related to one example of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT An example of the organic wastes digestion process of the present invention is illustrated in the drawing, with the detailed explanation made hereunder in the order of each step. First, the garbage or garbage contained wastes 2 which are stored in feedstock storage tank 1 are pulverized by crusher 3. Of course, if it does no harm the slurry transmission and stirring within the tanks at the steps to follow, this crushing process could be omitted. Next, water supplied from water tank 4 is added to the crushed garbage slurry if required to make the solids concentration in the slurry to 5-20%. Next, the slurry is charged into alcohol fermentation tank 6 and treated under a mix-cultured state of alcohol fermentation yeast, amylase producing yeasts, lipase producing yeasts and protease producing yeasts. Yeasts having strong alcohol fermentation activity such as Saccharomyces Genus (S. cerevisiae S. carlsbergensis), Schizosaccharomyces Genus (Schizosaccharo-myces pombe), Schwaniomyces Genus, Torulopsis Genus (T. dattila), Brettanomyces Genus, Candida Genus (C. Krusei), etc. are used as the alcohol fermentative yeast. As for amylase producing yeasts, Endomycopsis fibuliger, Schizosaccharomyces pombe, Saccharomyces diastatics, etc. are used. As for protease producing yeasts, Candida lipolitica, Candida parapsilosis, etc. are used, and, as for lipase producing yeasts, Candida cylindracea, Candida lipolitica, Trichosphoron pullulens, etc. are used. To treat with the aforementioned microorganisms, the slurry is kept stirred at a certain fixed temperature for several days, under an anaerobic condition. By this fermentation treatment, the carbohydrate contained in garbage is turned into alcohol, and the contained fat and protein are turned into lower molecular weight substances respectively. The temperature employed for fermentation is in the range of 20°-40° C., and it can be conveniently selected according to the microorganisms used and their combination. In case the pH decreases in the course of fermentation, it is necessary to add neutralizer so as to adjust it to the range of pH 4-6.5. As for neutralizer, slaked lime, calcium carbonate, and other alkaline materials containing lime, for instance, carbide residue can be used. As for stirring and maintenance of the temperature, the methods which have been employed in the conventional anaerobic digestion process are applied. The gas generated from the alcohol fermentation tank contains over 95% carbon dioxide, other than this, nitrogen, hydrogen and a trace of hydrogen sulfide. This gas is stored in gas storage tank 8, after eliminating hydrogen sulfide therefrom at desulfurizer 7. The slurry from the alcohol fermentation is charged into gasification tank 11, and low molecular substance which is mainly ethanol is converted into methane and carbon dioxide, by coming into contact with gasification bacteria (methane bacteria). For this gasification treatment to progress with satisfactory efficiency, it is required to keep up the temperature at the range of 20°-75° C. under an anaerobic condition and adjust pH to 7-8. As for gasification bacteria, those which have so for been in use, such as Methanosaricina Genus, Methanococcus Genus, Methanobacterium Genus, etc., can well be used. The main ingredients of the generated gas are methane 60-85% and carbon dioxide 15-40%, and further small amounts of nitrogen, hydrogen and hydrogen sulfide are also involved. The generating gas is stored in gas storage tank 10, after hydrogen sulfide is removed by desulfurizer 9. Following gasification the slurry is lead into solids/liquid separation tank 12 for the final treatment where it is separated to separated water 13 and digestive sludge 14. The following Examples are given as illustrative of the present invention. EXAMPLE 1 A slurry of 10% organic concentration (solids concentration 12%) was prepared by adding water to garbage contained wastes (garbage content: dry waste 70%, water 50% and) crushed by a pulverizer. Three kg of the aforementioned slurry was mixed with 0.5 kg of seed culture prepared in advance by mix-culturing Saccharomyces Cerevisiae Saccharomyces diasbtitics and Candia lipolitica under an anaerobic condition at pH 5 and 30° C. for 3 days, and this mixture was charged into a cylindrical stainless steel container of 5l effective capacity equipped with a stirrer, jacket and a pH adjusting system. Next, the mixture therein was processed through a liquefaction fermentation treatment by stirring at 100 rpm and at 30° C. and pH 5.0 for 3 days, then from the 4th day onward a continual charging was effected at organics load of 25 g - dried organics/d. At the end of the 10th day from commencement of a continual charging, the alcohol concentration of the slurry was 3.0% (W/W) and the generated gas volume was 16 Nl/kg-slurry (carbon dioxide 95 vol %, hydrogen 2 vol %, others 3 vol %), and the volume of slaked lime required for neutralization was 1.1 g/kg-slurry. Next, the slurry treated by the aforementioned fermentation treatment was transferred into a gasification tank of a 20l effective capacity at the rate equal to the discharging velocity from the liquefaction tank, and a gasification treatment was conducted therewith. The gasification tank has a stirrer, jacket and an automatic pH adjusting system the same as the liquefaction tank. The gasification wasexercised under the conditions of slurry volume within the tank of 10.5l, residence time of 12 days and at 60° C. and pH 7.8. As for the gasification seed culture, the slurry used was the digested garbage contained slurry subjected, in advance, to the liquefaction treatment under the same conditions as aforementioned under the anaerobic conditions at pH 7.6 and 30° C. for 10 days. The gas generation from the gasification tank was 35 N l/kg-slurry (methane concentration 75 vol%) at the end of 10 days after commencement of continual charging, of which mathane was 26.3 N l/kg-slurry and carbon dioxide was 8.7 n l/kg-slurry. COMPARATIVE EXAMPLE 1 As a reference against Example 1, the following experiment was performed. A slurry of organics concentration 10 wt% (solids concentration 12 wt %) was prepared by adding water to the garbage contained wastes taken from the identical batch of the starting material of the aforementioned Example 1 and crushed by a pulverizer. Three kg of the aforementioned wastes slurry and 0.5 kg of seed culture prepared in advance by mix-culturing the aforementioned wastes slurry and volatile fatty acid producing bacteria (liquefaction fermentation bacteria) at pH 5.8 and 60° C. under an anaerobic condition were charged into a liquefaction tank with the specifications identical to the tank employed in Example 1. Next, batchwise fermentation was exercised with in-tank slurry volume of 3.5l, with stirring at 100 rpm, at 60° C. and pH 5.8 for 3 days. After completion of fermentation, a continual charging at the rate of garbage contained wastes of 875 g/d (organics load: 25 g-dried organics/l.d) and a residence time of 4 days was mode. At the same time a continual discharge equivalent to the charged volume was made. At the end of 10 days after commencement of the continual charging, volatile fatty acid concentration within the slurry was 3.2 wt % (n-butyric acid 1.9%, acetic acid 1.1%, other fatty acids 0.2%), and the generated gas volume was 19.3 Nl/kg-slurry (carbon dioxide 55 vol %, hydrogen 45 vol %), and the volume of slaked lime required for adjustment of pH in the course of fermentation was 20.1 g/kg-slurry. Next, a continual gasification treatment was performed by charging the slurry subjected to the liquefaction fermentation treatment into the gasification tank having the identical specifications to the one used in Example 1 with the charging rate idential to that of the discharging slurry from the liquefaction tank. The gasification fermentation treatment was exercised under the conditions of the liquid volume within the tank of 10.5l, residence time of 12 days, stirring speed of 100 rpm., liquid temperature of 30° C. and pH of the liquid of from 7.4 to 7.6. As for the seed culture for gasification fermentation, the slurry used was the digested garbage contained slurry subjected, in advance, to the liquefaction treatment under the same conditions as aforementioned under anaerobic conditions at pH 7.6 and 60° C. for 10 days. The generated gas volume at the end of 10 days after commencement of the continual charging was 32.9 Nl/kg-slurry (methane concentration 70 vol %) of which methane was 22.4 Nl/kg-slurry and carbon dioxide was 9.7 Nl/kg-slurry. Comparing Example 1 with Comparative Example 1, by applying the present invention the recovered volume of methane was improved by 18% as against Comparative Example 1 and the methane concentration was increased to 75 vol % as against the 70 vol % of Comparative Example 1. Furthermore, by the present invention the volume of slaked lime consumed at the time of liquefaction fermentation for each 1 kg of the wastes slurry was reduced by 95% as compared with Comparative Example 1. EXAMPLE 2 After mixing 20 kg of water with 20 kg of garbage wastes (water content 75 wt %), and by mixing this mixture by a home mixer for 2 minutes, a slurry of solids concentration 12.5 wt % and organics concentration 9.8 wt % was prepared. Next, 0.5 kg of a liquefied seed culture prepared by mix-culturing in advance 1.5 kg of the garbage wastes of the identical batch to the aforementioned garbage wastes and four kinds of yeast of Saccharomyces Carlsbergensis, Schizosaccharomyces pombi, Candida parapsilosis and Candida cylindracia was charged into a cylindrical acrylic plastic fermentation tank of a 2l capacity equipped with a stirrer, jacket, and an automatic pH adjusting system. The resultant mixture was subjected to a liquefaction fermentation treatment for 3 days by stirring at 100 rpm, at 30° C. and pH 5.0-5.4. For guidance, the aforementioned seed culture was prepared by mixing 2 kg of the garbage wastes taken from the batch identical to the aforementioned one and the aforementioned four kinds of yeast and by subjecting it to a fermentation treatment at pH 5.0-5.4 and 30° C. with stirring at 100 rpm for 4 days. The alcohol concentration in the aforementioned liquefied/fermented slurry was 2.3 wt % and the generated gas volume was 10.7 Nl/kg-slurry (carbon dioxide 98 vol %, hydrogen 1.5 vol %, others 0.5 vol %). The slaked lime required for adjusting the pH in the course of fermentation was 2.2 g/kg-slurry. Next, by charging 0.5 kg of the aforementioned liquefied/fermented slurry and 1.5 kg of the seed culture for gasification fermentation treatment into a fermentation tank of a 2l capacity with the identical specifications to that used for the aforementioned liquefaction fermentation treatment, a batchwise gasification fermentation treatment was performed at pH 7.6-7.8 and 30° C. and with stirring at 70 rpm for 10 days. The gasification seed culture, used was prepared from the mixture of the garbage wastes slurry of the identical batch to the aforementioned one and middle temperature methane bacteria which were both charged into a 20l acrylic plastic fermentation tank and cultured under an anaerobic condition at 30° C. and pH 7.6-7.8 for 1 month. The generated gas volume in the course of a 10 day fermentation was 36.9 Nl/kg-slurry (methane purity 90 vol%), of which methane was 33.2 Nl/kg-slurry, carbon dioxide 3.7 Nl/kg-slurry. EXAMPLE 3 1.5 kg of garbage slurry from the identical batch which was used for Example 2 (organics concentration 9.8 wt %) and 0.5 kg of the liquefaction seed culture which was prepared in advance by mix-culturing four kinds of yeasts of Candida Krusei, Endomycopsis filubiger, Candida parapilosis and Trichosporon pullulens was charged into a cylindrical acrylic plastic fermentation tank of 2l effective capacity equipped with a stirrer and jacket and an automatic pH adjusting system and was subjected to a liquefaction fermentation treatment with stirring at 100 rpm for 3 days at 30° C. and pH 5.0-5.4. For guidance, the aforementioned liquefaction seed culture was prepared by adding the aforementioned four kinds of yeasts to 2 kg of the garbage slurry of the identical batch as the aforementioned one and fermented with stirring at 100 rpm at 30° C. and pH 5.0-5.4 for 4 days. The alcohol concentration in the aforementioned slurry liquefied/fermented for 3 days was 2.8 wt %, and the generated gas volume was 13.0 Nl/kg-slurry (carbon dioxide 96 vol %, hydrogen 3 vol %, others 0.4 vol %). The slaked lime required for adjusting the pH during fermentation was 2.5 g/kg-slurry. Next, 0.5 kg of the aforementioned liquefied slurry and 1.5 kg of the seed culture for gasification fermentation were charged into a 2l fermentation tank with the identical specifications to the one which was used for the aforementioned liquefaction treatment, and a batchwise gasification fermentation was effected withstirring at 70 rpm for 10 days at 60° C. and pH 7.6-7.8. The gasification seed culture used was prepared by culturing the garbage slurry from the identical batch to the aforementioned one and middle temperature gasification fermentation bacteria (middle temperature methane bacteria) in a 20l acrylic plastic fermentation tank under an anaerobic condition at 60° C. and pH 7.6-7.8 for over 1 month. The volume of gas recovered at the end of fermentation was 39.0 Nl/kg-slurry (methane purity 89.5 vol %), of which methane was 35.4 Nl/kg-slurry and carbon dioxide 3.6 Nl/kg-slurry EXAMPLE 4 1.5 kg of garbage slurry from the batch identical to the one used for Example 2 (organics concentration 9.8 wt %) and 0.5 kg of liquefaction seed culture obtained by mix-culturing in advance two kinds of yeasts of Saccharomyces cerevisiae and Saccharomyces diastatics were charged into a 2l effective capacity cylindrical acrylic plastic fermentation tank equipped with a stirrer, jacket and an automatic pH adjusting system and subjected to a liquefaction fermentation treatment with stirring at 100 rpm, at 30° C. and pH 5.0-5.4 for 3 days. The aforementioned liquefaction seed culture was prepared through fermentation treatment of the garbage slurry from the batch identical to the aforementioned one with added yeasts of the aforementioned two kinds, at 30° C. and pH 5.0-5.4 with stirring at 100 rpm for 4 days. The alcohol concentration in the aforementioned slurry liquefied/fermented for 3 days was 2.5 wt %, and the generated gas volume was 10.9 Nl/kg-slurry (carbon dioxide 97 vol %, hydrogen 2.5 vol %, others 0.5 vol %). The volume of slaked lime consumed for adjusting the pH during fermentation was 4.0 g/kg-slurry. Next, 0.5 kg of the aforementioned liquefied slurry and 1.5 kg of the seed culture for gasification fermentation were charged into a 2l fermentation tank with specifications identical to the one which was used for the aforementioned liquefaction, and were subjected to a batchwise gasification fermentation with stirring at 70 rpm and at 60° C. and pH 7.6-7.8 for 10 days. The seed culture for gasification was prepared from garbage slurry of the batch identical to that of the aforementioned one with added middle-temperature gasification bacteria (middle-temperature methane bacteria) and the mixture thereof was charged into a 20l acrylic plastic fermentation tank for culturing under an anaerobic condition at 60° C. and pH 7.6-7.8 for over 1 month. The volumeof recovered gas at the end fermentation was 37.0 Nl/kg-slurry (methane purity 87 vol %), of which methane was 32.2 N l/kg-slurry and carbon dioxide 4.8 Nl/kg-slurry. EXAMPLE 5 1.5 kg of garbage slurry from the batch identical to the one which was used for Example 2 (organics concentration 9.8 wt %) and 0.5 kg of liquefaction seed culture obtained by mix-cultuing in advance two kinds of yeasts of Saccharomyces carlsbergensis and Candida lipolitica were charged into a cylindrical acrylic plastic fermentation tank of a 2l capacity equipped with a stirrer, jacket and an automatic pH adjusting system and were subjected to a liquefaction fermentation treatment with stirring at 100 rpm and at 30° C. and pH 5.0-5.4 for 3 days. The aforementioned liquefaction seed culture was prepared by adding the aforementioned two kinds of yeast to 2 kg of garbage slurry from the batch identical to the aforementioned one and fermented with stirring at 100 rpm and at 30° C. and pH 5.0-5.4 for 4 days. The alcohol concentration in the slurry liquefied/fermented 3 days was 2.2 wt %, and the generated gas volume during fermentation was 10.7 Nl/kg-slurry (carbon dioxide 98 vol %, hydrogen 1.6 %, others 2.4 vol %). The volume of slaked lime required for pH adjustment was 2.4 g/kg-slurry. Next, 0.5 kg of the aforementioned slurry after liquefaction treatment, together with 1.5 kg of seed culture for gasification, was charged into a 2l fermentation tank with the identical specifications as used for the aforementioned liquefaction treatment, and the mixture thereof underwent a batchwise gasification treatment with stirring at 70 rpm and at 60° C. and pH 7.6-7.8 for 10 days. The aforementioned seed culture for gasification was cultured by adding middle-temperature gasification bacteria (middle-temperature methane bacteria) to the garbage slurry of the batch identical to the aforementioned one and this mixture was charged into a 20l acrylic plastic fermentation tank wherein it was cultured under an anaerobic condition at 60° C. and pH 7.6-7.8 for over 1 month. The recovered gas volume at the end of fermentation was 35.0 Nl/kg-slurry (methane purity 90.5 vol %), of which methane and carbon dioxide were 32.6 Nl/kg-slurry and 3.4 N l/kg-slurry respectively. EXAMPLE 6 1.5 kg of the garbage slurry from the batch identical to the one used for Example 2 (organics concentration 9.8 wt %) and 0.5 kg of liquefaction seed culture prepared in advance by culturing Saccharomyces diastics were charged into a cylindrical acrylic plastic fermentation tank of an 2l capacity equipped with a stirrer, jacket and a automatic pH adjusting system, and the mixture therein was subjected to a liquefaction fermentation with stirring at 100 rpm and at 30° C. and pH 5.0-5.4 for 3 days. The aforementioned seed culture was prepared by adding the aforementioned yeast to 2 kg of the garbage slurry from the batch identical to the aforementioned one and fermented at 30° C. and pH 5.0-5.4 with stirring at 100 rpm for 4 days. The alcohol concentration in the aforementioned slurry liquefied/fermented for 3 days was 2.1 wt % and the generated gas volume was 10.8 Nl/kg-slurry (carbon dioxide 97 vol %, hydrogen 2.6 vol %, others 0.4 vol %). The volume of slaked lime required for pH adjustment in the process of fermentation was 2.1 g/kg-slurry. Next, into a 2l fermentation tank with the specifications identical to those of the tank used for the aforementioned liquefaction, 0.5 kg of the aforementioned liquefiled slurry and 1.5 kg of gasification fermentation seed culture were charged for a batchwise gasification fermentation at 60° C. and pH 7.6-7.8 with stirring at 70 rpm for 10 days. The gasification seed culture was prepared from the garbage slurry from the batch identical to the aforementioned one, which was charged into a 20l acrylic plastic fermentation tank together with middle-temperature gasification fermentation bacteria (middle-temperature methane bacteria) and was cultured under an anaerobic condition at 60° C. and pH 7.6-7.8 for over 1 month. The recovered gas volume at the end of fermentation was 35.6 N l/kg-slurry (methane purity 9.10 vol%), ofwhich methane and carbon dioxide were 32.6 Nl/kg-slurry respectively. COMPARATIVE EXAMPLE 2 As a reference to compare with Examples 2 through 6 the following experiment was performed. 1.5 kg of the garbage slurry of the batch identical to the one used for the aforementioned Example 2 (organics concentration 9.8 wt %) and 0.5 kg of the seed culture of volatile fatty acid generating bacteria (liquefaction fermentation bacteria) which was mix-cultured in advance with the aforementioned garbage slurry under an anaerobic condition at 30° C. and pH 5.8 for 3 days were charged into a liquefaction tank having specifications identical to the one which was used in Example 2, nd the mixture therein was subjected to a liquefaction fermentation for 3 days with stirring of 100 rpm at 30° C. and pH 5.8. The aforementioned seed culture was prepared through fermentation treatment of 2 kg of the garbage slurry taken from the batch identical to the aforementioned one together with the aforementioned volatile fatty acid generating bacteria with stirring at 100 rpm and at 30° C. and pH 5.8 for 4 days. The concentration of volatile fatty acid in the aforementioned slurry liquefied/fermented 3 days was 2.2 wt % (n-butyric acid 1.2 wt %, acetic acid 1.1 wt %, other fat acids 0.1 wt %), and the generated gas volume was 12.9 Nl/kg-slurry (carbon dioxide 51 vol %, hydrogen 47 vol %, others 5 vol %). The volume of slaked lime consumed for pH adjustment during fermentation was 19.0 g/kg-slurry. Next, into a 2l fermentation tank of identical specifications to that which was used for the aforementioned liquefaction treatment, 0.5 kg of the above liquefied slurry and 1.5 kg of gasification fermentation seed culture were charged and a batchwise gasification fermentation was performed at 30° C., pH 7.6-7.8 with stirring at 70 rpm for 10 days. As for the gasification seed culture, that which was used was prepared from the garbage slurry taken from the identical batch to the aforementioned one and adding thereto middle-temperature methane bacteria. The mixture thereof was charged into a 20l acrylic plastic fermentation tank wherein the mixture was cultured under an anaerobic condition at 30° C. and pH 7.6-7.8 for over 1 month. The gas generation volume in the course of 10 days of fermentation was 32.6 Nl/kg-slurry (methane purity 75.2 vol %), of which methane and carbon dioxide were 24.5 vol % /kg-slurry and 8.1 vol %/kg-slurry respectively. In comparing the aforementioned Examples 2 through 6 with Comparative Example 2, it is clear that the recovered volume of methane was improved by 13% on the average as against Comparative Example 2, and at the same time the methane purity was improved to 89.6 vol/% on the average as against 75.2% in Comparative Example 2. Furtheremore, the volume of slaked line consumed for liquefaction fermentation per 1 kg of garbage slurry was reduced by 86% on the average as against Comparative Example 2. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

4y

FIELD OF THE INVENTION [0001] The present invention pertains to digester tanks and reactors, and, more particularly pertains to a continuously operational double drum biological reactor for environmentally safe aerobic decomposition of bulk animal and livestock waste. BACKGROUND OF THE INVENTION [0002] Farm animals and farm livestock, such as cattle, sheep, goats, and pigs, produce tens of millions of tons of waste each year. The disposal of such waste presents both problems and opportunities for farms and farmers ranging from the small family owned generational farm to the large corporate farms and for the feed livestock yards and food processing plants. The opportunity that presents itself is that if properly treated such waste can be transformed into valuable fertilizer for enhancing crop productivity and yields for that particular farm; or as a commodity that can be sold for profit. The ability to transform livestock waste into a salable commodity is of particular importance for small family-type farms whose profit margin is slight and tenuous. The problem faced by farms of all types is that local, state and federal laws, from township zoning ordinances to federal EPA and USDA regulations regulate and control the treatment, removal, disposal, reuse and recycling of animal waste. Numerous regulations and standards must be adhered to before, for example, livestock manure can be reprocessed for sale and use as natural fertilizer. [0003] The prior art discloses a number of different tanks and drums for decomposing and processing waste and refuse material into useful soil fertilizer. [0004] For example, the Emmet patent (U.S. Pat. No. 3,248,175) discloses a rotatable drum for manufacturing compost that includes a plurality of spaced openings at one end surface of the drum that can be selectively opened or closed to allow the discharge of the warm moist air or the air-steam mixture being piped through the drum. The conduit for the air extends in a u-shaped manner within the drum. [0005] The Chester patent (U.S. Pat. No. 3,890,129) discloses a composting device that has open mesh side and end panels. For aerobic treatment, removable covers are placed over the open mesh side panels and when composting is completed, the covers are removed so that the composted material can be discharged through the mesh panels. For anaerobic treatment, both the mesh side panels and ends are covered to restrict airflow for such anaerobic treatment. [0006] The Kaelin patent (U.S. Pat. No. 3,960,537) discloses a method and device for treating refuse and sludge and includes a chamber having an upper inlet aperture for receiving the material to be treated and a lower outlet aperture for discharge of the material. Sets of gas distributor blades are axially disposed along a vertical shaft for introducing a gas mixture into the chamber for treating the material. [0007] The Terry patent (U.S. Pat. No. 4,024,219) discloses a drum for aerobic processing of waste material and includes a chamber through which a horizontal shaft extends, and projecting from the shaft are three vanes for effecting mixing and processing of the material. [0008] The Cook patent (U.S. design Pat. No. 352,580) discloses a double drum design wherein two drums are mounted on a stand side-by-side for composting material. [0009] The Kakuk et al. patent (U.S. Pat. No. 5,432,088) discloses a bin for aerobic composting that includes a plurality of horizontal mixing and aeration slots through which an implement, such as a garden tool, can be inserted for effecting the mixing of the material held within the bin. [0010] Despite the ingenuity of the above devices, there remains a need for a continuously operable aerobic digester that can expedite the process of transforming waste material continually fed therein to safe and useful fertilizer. SUMMARY OF THE INVENTION [0011] The present invention comprehends a continuously operable biological reactor for processing animal waste material into environmentally safe, chemically free natural fertilizer and includes a pair of drums, specifically an inner drum and an outer drum coaxially mounted on a horizontally extending center shaft for aerobic processing of animal waste material by continually moving animal waste material through the inner drum in one direction and then through the outer drum in the opposite direction. Each drum includes a series of conveyor threads or flights for turning over and moving the material therethrough, with the conveyor threads of each drum being angled in the opposite direction so that the waste material can move down the inner drum and then back up the outer drum in the opposite direction. The biological reactor also includes a dewatering press for removing excess water from the material received from a hopper, a mixer wherein microbes are introduced to facilitate material processing and a heater for directing a continuous airflow into both drums while the center shaft includes passageways for control and monitoring instrumentation and airflow passageways. [0012] It is an objective of the present invention to provide a continuously operational reactor for digesting animal waste matter using a screw-type conveyance design. [0013] It is another objective of the present invention to provide a continuously operational reactor wherein the animal waste matter is quickly brought to the aerobic state for processing by a pair of coaxially mounted rotatable drums. [0014] It is yet another objective of the present invention to provide a continuously operational biological reactor having a center shaft on which processing drums are mounted and through which instrumentation and airflow can be directed. [0015] It is still another objective of the present invention to provide a continuously operational biological reactor wherein animal waste material is input and environmentally safe fertilizer is output that meets all state and federal guidelines and regulations. [0016] It is still yet another objective of the present invention to provide a continuously operational biological reactor that processes animal waste into chemically-free fertilizer thereby decreasing the pollution of ponds, rivers, and water tables from the uncontrolled runoff, decay and degeneration of animal waste. [0017] Still another objective of the present invention is to provide a continuously operational biological reactor that is able to process canning factory waste into chemically free, environmentally safe fertilizer for sale or farm use. [0018] Still yet another objective of the present invention is to provide a continuously operational biological reactor capable of processing the waste product generated in the milking area of a diary farm into useful, environmentally safe fertilizer. [0019] Still yet a further objective of the present invention is to provide a continuously operational biological reactor that is transportable within a container to different sites, and is capable of processing one ton of animal waste an hour and up to 24 tons of animal waste daily. [0020] A yet further objective of the present invention is to provide a continuously operational biological reactor that allows for on site processing and treatment of waste material thereby avoiding the cost and time of transporting such waste to a dump site or landfill. [0021] These and other objects, features and advantages will become apparent upon a perusal of the following detailed description when read in conjunction with the drawings and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0022] FIG. 1 is a sectioned elevational view of the continuously operational biological reactor of the present invention illustrating the movement of animal waste material through the inner drum and then the outer drum; [0023] FIG. 2 is a top plan view of the continuously operational biological reactor of the present invention illustrating the location of the hopper, the chute and the inner an outer drum; [0024] FIG. 3 is a sectioned elevational view of the continuously operational biological reactor taken along line 3 - 3 of FIG. 1 illustrating the coaxial alignment of the inner and outer drums on the center shaft; [0025] FIG. 4 is a bottom plan view of the continuously operational biological reactor illustrating the air flow pattern through the inner drum, the outer drum, and the center shaft; [0026] FIG. 5 is a sectioned elevational view taken along lines 5 - 5 of FIG. 3 illustrating the instrumentation and air flow passageways extending through the center shaft; and [0027] FIG. 6 is a basic flow chart illustrating the control and monitoring events that occur concomitant with the movement of the waste material through the biological reactor. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0028] Illustrated in FIGS. 1-6 is a continuously operable biological digester or reactor 10 for treating and processing animal waste, primarily from farm and livestock animals, into a natural fertilizer that is chemical free and environmentally safe and approved by the relevant government agencies. By treating and processing the animal waste (predominantly animal excrement) on site, the pollution of soil, streams, lakes, rivers and aquifers from seepage and runoff of the animal waste is prevented; and a salable commodity is produced for the farmer or other user of the reactor 10 . [0029] As shown in FIGS. 1-6 , the biological reactor 10 includes an external housing or frame 12 preferably of black iron. Mounted at a first end of the frame 12 , and extending into the frame 12 , is a hopper 14 into which the animal waste is dumped from a conveyor or other piece of machinery such as a back hoe or ditch digger. The hopper 14 can include some type of screen or scrubber for removing or breaking down sticks, rocks and other non-digestible material intermingled with the animal waste. The hopper 14 is connected to a dewatering device 16 that is preferably an agricultural press operating at 120 psi; the dewatering device 16 compresses the animal waste for removing excess water from the waste and it is also where the preheating of the animal waste occurs. A worm conveyor (not shown) extends through the dewatering device 16 and acts on the animal waste passing through the dewatering device 16 . [0030] Illustrated in FIGS. 1 and 4 is a furnace 18 that is preferably a 100 BTU heater with a three-speed fan or blower. The furnace 18 is mounted to the inside of the frame 12 by means of struts or support members 20 . Attached to the furnace 18 is a plenum chamber 22 for directing the flow of air from the furnace 18 into air ducts 24 extending outwardly from the plenum chamber 22 . The purpose of the airflow (shown by the directional arrows of FIG. 4 ) is to dilute and discharge the methane that is a constituent and by-product of the animal waste, and to keep the methane—and other gasses—moving through the reactor 10 as will be hereinafter further explained. Adjoined to the dewatering device 16 is a mixer 26 , and as the animal waste is conveyed through the mixer 26 , microbes are introduced to facilitate the breakdown and decomposition of the animal waste. In addition, air is introduced into the mixer 26 for intermixing with the animal waste and for providing the aerobic processing conditions. [0031] As illustrated in FIGS. 1 and 2 , attached to the mixer 26 and angled downwardly therefrom is a double-chambered chute 28 . The animal waste downwardly descends within both chambers of the chute 28 , and the chute 28 will include a back pressure plate that will operate as a safety valve if excessive pressure differentials occur within the reactor 10 . The chute 28 communicates with the two primary components of the reactor 10 : an inner reactor drum 30 and an outer reactor drum 32 . Both the inner drum 30 and the outer drum 32 are coaxially mounted to a center shaft 34 , and air ducts 24 interconnect the center shaft 34 to the furnace 18 so that airflow can be directed through the center shaft 34 and to the drums 30 and 32 . The drums 30 and 32 can be manufactured from stainless steel or from fiberglass and each drum 30 and 32 includes an inner annular surface 36 . The inner drum 30 and the outer drum 32 include a plurality of conveyor flights or threads 38 secured, preferably by welding, to their respective inner annular surfaces 36 ; and the conveyor threads 38 extend along the entire inside annular surface 36 of each respective drum 30 and 32 . The conveyor threads 38 for each drum 30 and 32 project inwardly from each respective inner surface 36 at least 12 inches and to facilitate the movement of the animal waste through, first, the inner drum 30 , and then the outer drum 32 , the conveyor threads 38 for the inner drum 30 are set at an angle that is opposite of the conveyor threads 38 of the outer drum 32 . The inner drum 30 has a first ingress end that registers with the double-chambered chute 28 for receiving the animal waste, and an opposite egress end having at least one discharge aperture 40 through which animal waste flows for processing within the outer drum 32 . In addition, air ducts 24 register with the outer drum 32 to maintain the flow of air therethrough. When the treatment and processing of the animal waste is completed, the treated waste flows through an outlet 42 for discharging and transferring to, for example, a waiting conveyor, bagging unit or dump truck. In addition, an air vent 44 for externally venting air, and especially the methane gas, can be included as shown in FIG. 4 . [0032] As shown in FIGS. 1-5 , the center shaft 34 is mounted to the inside of the frame 12 by shaft mounting members 46 , and the center shaft 34 extends through both the inner and outer drums 30 and 32 so that both drums 30 and 32 can rotate simultaneously and continuously thereon. The center shaft 34 includes bearing housings 48 located at opposed ends of the shaft 34 , and enclosed within the respective bearing housings 48 are machined bearing plates 50 and associated roller bearings 52 ; FIG. 5 shows the bearings 52 and bearing blocks 54 . In addition, as shown in FIGS. 3 and 5 , the center shaft 34 (preferably manufactured from steel tubing) includes passageways 56 for accommodating instrumentation and airflow, and the passageways 56 are coextensive with the shaft 34 . The center shaft 34 of the present invention includes four passageways 56 , two upper passageways for carrying instrumentation 57 and two lower passageways serving as airflow conduits. Also, instrumentation probes 58 are mounted to the center shaft 34 and extend into the interior of at least the inner drum 30 for monitoring such physical variables as temperature, ph levels, and gas content within the reactor 10 . At least six instrumentation probes 58 will be mounted to the center shaft 34 in the present embodiment of the invention. The center shaft 34 also includes a small space for accommodating a high pressure water conduit having spray nozzles spaced along the length of the conduit for discharging cleaning water through the nozzles and into the drums 30 and 32 for cleaning out the drums 30 and 32 . Moreover, the center shaft 34 is interconnected to the furnace 18 and plenum chamber 22 by air ducts 24 , as shown in FIG. 4 , and spaced along the center shaft 34 are air shaft vents 60 for directing airflow from the center shaft 34 into the inner drum 30 . [0033] Various drive or drum rotation means can be used with the reactor 10 , and a preferred drive means includes 20 hp variable speed motor appropriately geared down for rotating both drums 30 and 32 at the rate of three revolutions per hour for continuously turning the animal waste and moving the animal waste through both drums 30 and 32 . Power for the motor can be supplied from an appropriately rated electrical outlet or from an optional generator. A PLC controller 62 will monitor and control the various functions and parameters of the reactor 10 , such as the ph balance, the temperature, and the gas levels, throughout the processing steps shown in the processing flowchart 64 of FIG. 6 . [0034] In operation animal waste would be dumped into the hopper 14 where sticks and rocks would be screened for removal or broken up for digesting by screeners and/or scrubbers. For maximum digesting efficiency material should not exceed two inches in length or diameter. The animal waste is then compressed and preheated by the dewatering device 16 and then the animal waste enters the mixer 26 where the microbes are introduced for decomposing the animal waste by natural means. Air is also injected in the mixer 26 for providing the aerobic element to the processing of the animal waste. Thus, the animal waste is preheated and brought up quickly to the aerobic state whereby the ph and temperature are monitored and controlled by the PLC controller 62 (which can be from an external manually operable panel of known construction) to maintain the preheated aerobic state before the animal waste descends through the chute 28 and into the inner drum 30 . The flow of air from the furnace 18 and plenum chamber 22 , through the air ducts 24 , and then through the inner drum 30 and the outer drum 32 dilutes and discharges the methane so that the methane's flammability is nullified. The flow of air through the center shaft 34 occurs simultaneous with the airflow through the inner and outer drums 30 and 32 . The animal waste moves through the inner drum 30 by the rotatable action of the conveyor threads 38 , and as the animal waste moves through the inner drum 30 , the PLC controller 62 monitors events in the dewatering device 16 , the furnace 18 and the mixer 26 so that the proper temperature and ph balance is maintained before the animal waste enters the inner drum 30 . [0035] The movement of animal waste from the hopper 14 and through the inner drum 30 and then in the reverse direction through the outer drum 32 is shown by the directional arrows of FIG. 1 . The outer drum 32 is the slower digesting drum and thus the animal waste has a longer dwell time while going through the outer drum 32 . The slower digesting of the outer drum 32 allows for a cooling down of the waste as the temperature is carefully monitored to allow for the gradual cooling of the animal waste before discharge from the outer drum 32 . Both the inner and outer drums 30 and 32 turn the animal waste at three revolutions per hour, and generally more solid material moves into the outer drum 32 from the inner drum 30 : for example, if 10% of the material is solid entering the inner drum 30 , the material is approximately 38-45% solid as it is discharged from the inner drum 30 to the outer drum 32 . The approximate weight of the animal waste is 66 pounds per cubic foot, and the configuration of the drums 30 and 32 provides for a discharge of 30 cubic feet of material from each drum 30 and 32 per hour thereby providing for the production of one ton of natural fertilizer per hour. It should be note that the biological reactor 10 of the present invention will not work with any material that will kill the biological microbes such as material from the family of hydrocarbon compounds. Thus, the present invention is a continuously operable biological reactor 10 in contrast to batch processors that go from anaerobic to aerobic and then back to anaerobic processing states. [0036] It will be seen that a preferred embodiment of the invention is disclosed, and that those skilled in the art will recognize that numerous alterations, modifications, and variations can be made that will still fall within the scope of the above detailed description and the following appended claims.

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This application is a continuation-in-part of application Ser. No. 839,982 pending, filed Feb. 20, 1992, which is itself a division of U.S. Ser. No. 626,132 filed Dec. 11, 1990, now U.S. Pat. No. 5,145,785. CROSS REFERENCES TO RELATES APPLICATION U.S. patent application Ser. No. 506,391, pending filed Apr. 9, 1990 by S. M. Maggard (docket number 6362AUS) relates to the determination of PIANO components in hydrocarbons by near infrared spectroscopy and is therefore related to the field of the present invention. BACKGROUND OF INVENTION I. Field of the Invention The present invention relates to the determination of aromatic and/or organic sulfur and/or color constituents in hydrocarbons by near infrared spectroscopy and is generally classified in U.S. Patent Office Class 250, subclass 343, 341, and 339. II. Description of the Prior Art U.S. Pat. No. 4,963,745 granted Oct. 16, 1990 for octane measuring process and device to S. M. Maggard teaches the use of near infrared absorbance of the methyne band to measure octane, etc. of a fuel by near infrared spectroscopy. The aforementioned U.S. Ser. No. 506,391 teaches the determination of the constituents of PIANO aromatics (paraffins, aromatics, isoparaffins, naphthenes, and olefins) by near infrared techniques. U.S. Pat. No. 4,880,279, and the references cited thereon, to Hieftje et al. relates to the determination of properties of hydrocarbons by near infrared absorbance. European Patent Office 2,852,251 filed 10/1988 relates to the general field of analysis by near infrared spectroscopy. "Near-Infrared Reflectance Analysis by Gauss-Jordan Linear Algebra", D. E. Honigs, J. M. Freelin, G. M. Hieftje, T. B. Hirschreid, Applied Spectroscopy, vol. 37, no. 6, 1983, pp 491-497, teaches statistical manipulation of NIR spectral data. "Prediction of Gasoline Octane Numbers from Near Infrared Spectral Features in the Range 660-1215 nm" by J. J. Kelly et al., Analytical Chemistry, vol. 61, no. 4, Feb. 15, 1989, pp 313-320, relates to the prediction of octane. Also by Kelly et al., "Nondestructive Analytical Procedure for Simultaneous Estimation of the Major Classes of Hydrocarbon Constituents of Finished Gasolines", Analytical Chemistry, vol. 62, no. 14, Jul. 15, 1990, pp 1444-1451. Percents of each of the individual compounds detected by gas chromatography are grouped under their respective generic classifications in the PIANO classification system, and the relative percentage of each of the components paraffins through olefins is determined in weight percent, volume percent, or mole percent as required. An example of this procedure is that taught by Analytical Automation Specialists, Inc., "The Detailed Analysis of Petroleum Naphthas, Reformates, Gasoline and Condensates by High-Resolution Gas Chromatography", Operators Manual, P.O. Box 80653, Baton Rouge, La. 70898. Also available is AAS (Analytical Automated Systems) PIANO Software Package, Sievers Research PIANO Software Package. Other NIR analysis techniques are taught in J. Prakt. Chem., 317(1), 1-16 by Bernhard and Berthold, who perform structural group analysis of mixtures of saturated and aromatic hydrocarbons, and in the quantitative analysis of benzene-toluene-paraffin mixtures in the near-infrared by Leimer and Schmidt in Chem. Tech. (Leipzig), 25(2), 99-100. "Near-infrared spectroscopy of hydrocarbon functional groups was performed by Tosi and Pinto, Spectrochim ACTA, Part A, 28(3), 585-97, who examined 50 linear and branched paraffins and related the absorbtivities to the concentration of the groups such as CH 3 and CH 2 . Ultraviolet and near-infrared analysis of mixtures of aromatics is taught by Schmidt in Erdoelkohle, Erdgas, Petrochem., 21(6), 334-40, who sought to determine concentrations of specific compounds. Kelly, Barlow, Jinguji and Callis of the University of Washington, Seattle, (Analytical Chem. 61, 313-320,) Specialists, Inc., "The Detailed Analysis of Petroleum Naphthas, Refomates, Gasoline and Condensates by High-Resolution Gas Chromatograph", Operators Manual, P.O. Box 80653, Baton Rouge, La. 70898. Also available in AAS (Analytical Automated Systems) PIANO Software Package, Sievers Research PIANO Software Package. Hydrotreating is taught by many chemical engineering texts. "Reduction of Aromatics in Diesel Fuel" by A. J. Suchanek, National Petroleum Refiners Association, AM-90-21, 1990, provides a brief review. Other patents which relate to the general field of the invention are U.S. Pat. Nos. 4,277,326; 4,264,336; 3,496,053; 903,020; 4,323,777; 4,433,239; and 4,591,718 and 5,062,976. Each of the above references is understood to teach a correlation between the absorbance in the near infrared and some physical or chemical property. None of them teach an absolute determination for a very complex mixture such as diesel fuel, as is involved in the percent aromatics determined by the present invention. Also none of the references teach the determination of aromatics sulfur or color where GC separations are not possible due to co-elution. SUMMARY OF THE INVENTION I. General Statement of the Invention According to the present invention, the absolute concentration of aromatics color and/or sulfur is determined for mixtures with other hydrocarbons, preferably fuels, and most preferably diesel fuels, all grades, kerosene, fuel oils, all grades, light cycle oil, light vacuum oil, heating oils and vacuum oils as known in the petroleum industry. By measuring the absorption at a frequency in the range of 800-2500 nm (nanometers), most preferably from 1650-1700 or 2120-2256 nm, then correcting for the absorption due to non-aromatics in the sample at that frequency and, by data resolution, determining the absolute value of (or percent) aromatics in the sample. The invention can be practiced on a batch basis as in laboratory cells, or by a flow basis, e.g. by using fiber optic or other probes, and can be used for direct or indirect control of process variables such as hydrogen uptake, as illustrated in FIG. 3. Color is measured in the visible range about 400 to 700 nm, using the same or similar spectrophotometer. Standardization is an important feature of the present invention and is accomplished by separating the aromatics from the non-aromatics in the sample by use of well-known preparative high performance liquid chromatography, e.g. as described in Petroleum Derived Hydrocarbons, John D. Bacha, John W. Newman, and J. L. White, ACS Symposium series 303, Chapter 6. The concentration of the aromatics in the sample is then determined by measuring the absorbance of each of the two portions at the frequency being used (e.g. 1672 nm) and the absorbance of the aromatic fraction can be (but does not have to be) corrected by subtracting the absorbance of the non-aromatic fraction. The resulting solution of the equation: Y=mX+b+e can be used to determine the percent aromatics of many successive samples so long as the molecular constituents remain approximately the same, thus, for diesel fuel the preferred hydrocarbon mixture to be measured, only one standardization is needed for a long period and many analyses. In the above equation: m=the slope of the line (by the standard) X=the absorbance of the aromatics b=a constant which is determined by the fitting of the absorbance against the absolute weight values obtained above. Y=percent aromatics e=any error in the determination The elements of the invention are therefore preferably the determination of aromatics content in hydrocarbons, preferably in the diesel no. 2 fuel oil boiling range by: (a) separating the aromatics from the non-aromatics (saturates and olefins) in a representative sample, to be used as a calibrating standard, preferably by preparatory high performance liquid chromatograph ("prep.HPLC"); (b) measuring NIR absorbance of the resulting non-aromatics and aromatic portions (or of prepared known homogenous mixtures) derived from the above sample; (c) deriving the calibration equation and its constants by Beer-Lambert's Law or other well-known spectral data resolution techniques; (d) measuring the NIR absorbance of a representative sample using the above calibration equation, determine the aromatic and/or the non-aromatic content. II. Utility of the Invention The present invention, as described above, can be utilized for most fuels, preferably for diesel fuel, and preferably by measuring absorbance at a frequency in the range of 800-2500 nm, for aromatics most preferably 1650-1700 nm or 2120-2256 nm for organic sulfur: 850-900, 1118-1162, 1584-1642, 2036-2088, 2110-2152, and/or 2196-2282 nm, and for color: 400-700 nm or same portion thereof. The invention can be utilized as a batch process, in a flow-through cell, by the use of fiberoptic probes either bundled or single fiber, and the process control can be either feed-back or feed-forward based on the samples absorbance in the near-infrared, or optionally the first derivative of the samples absorbance or some other mathematical function of absorbance, being employed e.g. to operate a control valve. Increasing governmental regulation and environmental laws are impacting the permissible percentage of aromatics tolerated in diesel fuels, turbine fuels, kerosene, heating oils, and other oils. Therefore, the need for accurate, absolute determinations of the present invention, particularly for on-line control of aromatics in fuels is increasing rapidly. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a comparison of the repeatability error (% by absolute error) of four analytical methods for determining aromatics in diesel fuels (no. 2 fuel oil). The methods compared are fluorescent indicator absorption (FIA) by ASTM D-1319; mass spectroscopy (MS); super fluid chromatography (SFC) in which CO 2 above its critical pressure and temperature is used as the eluent; and near infrared according to the techniques of the present invention (NIR) for sets of 6 identical samples. This figure shows the excellent repeatability of the techniques of the present invention. (All determinations are in wt. % except FIA is in vol. %.) FIG. 2 is a comparison of the percent aromatics determined in identical sets of 4 samples by heated FIA (a), heated FIA plus water deactivation of the chromatographic column (b), SFC (c); HPLC/DCD (high performance liquid chromatography using a dielectric constant-measuring detector) (d); and the NIR of the present invention (e). Note that results are expressed in volume percent for the two FIA methods and the HPLC/DCD method, whereas SFC and NIR results are expressed in weight percent. Note that NIR (except in sample no. 2) is closest to the average of all methods combined. FIG. 3 is a schematic diagram of a control system utilizing the NIR techniques of the present invention to control a refinery hydrogenation unit in which sufficient hydrogen is added not only to combine with the sulfur, but also sufficient to cause scisson and destruction of aromatics in diesel fuel. FIG. 4 is a near infrared absorbance spectrum of the aromatic fraction of a diesel fuel which was obtained by HPLC. FIG. 5 shows a schematic control system as detailed in Example 4. FIG. 6 is a near infrared absorbance spectrum of a typical diesel fuel. FIG. 7 is a plot showing the correlation observed at each wavelength from 1100-2500 nm for the aromatic content of diesel fuels using the techniques of the current invention. Note the superior correlation discovered at 1650 to 1700 nm and at 2120 to 2256 nm, most preferably 1654 to 1696 nm, or 2124 to 2252 nm, or both. FIG. 8 is a near infrared (NIR) absorbance spectrum of the non-aromatic fraction of diesel fuel which was obtained by HPLC. FIG. 9 is a plot of multiple correlation vs. wavelength (nm) for organic sulfur. FIG. 10 is a plot of NIR results vs. ASTM methods D1552 (Leco) and D3120 (microcoulometry) for determination for organic sulfur. DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1 (The Invention Using Batch-Type NIR Cells) A diesel fuel sample (6 grams) is separated into its aromatic and non-aromatic fractions by passing (@500 ml./minute) the fuel down a silica diamine column connected in series to a silica gel column using hexane as the solvent on a Waters Div. Millipore, Milford, Mass., Model 500A high performance liquid chromatograph. The saturate fraction is collected off the end of the column and the hexane mobile phase is removed by rotary evaporation. The aromatics are then back flushed from the column by reversing the flow and substituting methylene chloride as the solvent. The solvent is again removed by rotary evaporation. The near infrared absorbance spectra of the non-aromatic and aromatic fractions (or known proportions thereof) are measured on an NIR Systems, Inc., Model 6500 spectrophotometer at 1672 nm and assigned concentrations of 0% and 100% aromatics by weight, respectively. An equation of the form Y=mX+b is calculated from Beer-Lambert Law, where Y is the aromatic concentration, X is the absorbance, m is the slope of the regression line, and b is its Y-intercept. The absorbances of a series of five unknown diesel fuel samples are measured and, using the above equation and the sample's absorbance at 1672 nm, aromatic concentration of each sample is calculated and the correlations are plotted together as FIG. 7. Note the near perfect correlation in the preferred bands of the invention. EXAMPLE 2 (Flow-Through Mode) When the techniques of Example 1 are employed using fiberoptic probes to measure flowing streams and side streams in a refinery diesel fuel stream, accuracy approximately as good as obtained in the batch-process of Example 1 is achieved. Fiber optical probes preferably use the NIR range of 1650 and 1700 nm because of the cost and difficulty in obtaining non-absorbing fiber probes which transmit in the range of 2124 to 2252 nm. EXAMPLE 3 (The Invention Controlling a Process) FIG. 3 schematically shows an important process control application of this invention. New diesel fuel regulations require that highway fuel produced after October, 1993, meet a maximum sulfur content specification. An NIR instrument calibrated as according to this invention, very close control of hydrotreater operation can be attained at minimum severity and hydrogen consumption. Raw feed, stream 300, flows through fired heater 310, feed/effluent exchanger 340, is admixed with hydrogen stream 320, through an adiabatic hydrotreating reactor 330, to tankage. The absorbance spectrum of the stream is measured by NIR probe 350, and this information provided to the process control computer 360. Conversion of spectrum to estimated sulfur content is made by the computer, and the flow of fuel stream 370 to the fired heater is adjusted as necessary by control valve 380. This on-line control allows rapid, very close control of product quality and eliminates present problems with production of off-spec finished products in quantities because corrections are implemented much sooner. This also results in a close-specification diesel fuel which is in much demand in today's marketplace. EXAMPLE 4 (Controlling Hydrotreater Severity) Additional process control advantages of the invention are exemplified in FIG. 5. For the same hydrotreating scheme shown in FIG. 3 (Example 3), this invention can allow maximum use of aromatic components in diesel fuel such as FCC LCO while operating the hydrotreater at maximum severity when aromatic/cetane limits are reached. Maximum use of FCC LCO (light cycle oil, high in aromatics) in diesel is advantageous to the refiner due to its relatively low value, but it is a major contributor to the aromatics content of the diesel pool. In FIG. 5, on-line NIR analysis allows maximum FCC LCO flow by maintaining constant analysis of the product diesel stream, providing information to the aforementioned process control computer 360 which adjusts FCC LCO flow 390 through flow control valve 400 such that the product stream just meets the required aromatics/cetane specification. This application is particularly attractive in that hydrotreating catalyst deactivation will be automatically compensated by the control loop by reducing the quantity of FCC LCO blended as the catalyst activity declines over the normal aging cycle. EXAMPLE 5 (Control of Aromatics in Solvents) Manufacture of Low Odor Base Solvent (LOBS) is accomplished by the control schematic of FIG. 3. An NIR probe, properly calibrated for 0-5% aromatics, is used to directly control product quality (low aromatic content) to meet the specification level, by hydrotreatment. Blending also can be controlled by NIR, preferably using feed-forward of the aromatics content of the feed as measured by NIR. EXAMPLE 6 (The Invention Controlling Desulfurizing by Hydrotreating) Using the same apparatus and using methods similar to those of FIGS. 3 and 4, the invention is used to control the sulfur in the final product diesel fuel existing from a hydrotreater using feed-back (feed-forward can be used to substitute for feedback or both feed-back and feed-forward control systems can be used, utilizing the invention as the primary sensor or sulfur). Recent U.S. government regulations will require a maximum of 0.05 wt. % sulfur in diesel fuels, so removal of sulfur by hydrotreating and close control to avoid excess consumption of hydrogen or off-spec high-sulfur diesel fuel have become increasingly critical to the refining industry. An important feature of the invention is the discovery that sulfur, at least predominantly, is usually present in diesel fuel and heavier hydrocarbons as a derivative of benzothiophene. Surprisingly, the C:S band of these thiophene or similar aromatic molecules can be observed by the NIR spectra of the present invention, despite the expectation that C:S would give a weak signal in comparison to C:H, due to the relative similarity of the carbon and sulfur molecular weights. Since there may be other aromatics present, e.g. mono, di, and tri aromatics, the ratio of aromatics to sulfur in any given petroleum feedstock, e.g. diesel fuel, can vary substantially because some of the aromatics will contain sulfur and is primarily present as derivatives of benzothiophene, a correlation can be made between the sulfur content and the aromatic content for any given feedstock. Showing this, the techniques of measuring and controlling sulfur are essentially the same as those utilized in Example 4 for controlling aromaticity by the invention. Once the ratio of total aromatics to benzothiophenes is known for each of the different feedstocks to be handled, measuring the aromatic content of the individual feedstock and applying the relationship between aromatics and thiophenes can be used to give a reliable measure of the sulfur content of a blended product. The invention can alternatively be used to directly compute the sulfur contained in each individual feedstock, or in the product if feed-back is being used, by monitoring the sulfur band itself which appears between 1584 and 1642 nm, and in some instances in the region 2036-2282 nm. As shown in FIG. 9, this is a region where there is also almost perfect correlation with aromatic content. Thus, through there may be a distinct sulfur band in the 2036-2282 region, it appears that it is interfered with by the strong aromatic band, but this is not yet determined due to the difficulty in band assignments. There is a second overtone of the benzothiophene absorption band at about 1100-1150 nm, and a third overtone at about 850-900 nm, and these can be used, either directly or by mathematical conversion to provide a measure of sulfur in diesel fuels and heavier hydrocarbon streams, through these overtones may also sulfur from the aromatic combination band interference. There may well be distinct sulfur bands in the primary, secondary and tertiary overtone combination regions. A combination of the primary band and these overtones may, in some instances, be valuable for analytical measurement of sulfur. Referring to FIG. 5, on-line NIR analysis in the benzothiophenic band determines sulfur in the product diesel oil stream, providing information to the process control computer 360 which adjusts FCC LCO flow 390 through flow control valve 400 so that the product stream just meets the required maximum sulfur specification. As with aromatics control, this application is particularly attractive because the hydrotreating catalyst's gradual deactivation will be automatically compensated for by the control loop reducing the quantity of FCC LCO fed to the unit. Preferably, with sulfur, we have found wavelengths in the ranges 850-900 1118-1162, 1584-1642, 2036-2088, 2110-2152, or 2196-2282 nm to be analytically useful for determining sulfur content. The statistical method is more fully set forth in Example 7. EXAMPLE 7 (Statistical Method for the Determination of Sulfur in Diesel) Table A shows calibration results by forty samples which include one feed sample and 39 samples that have been hydrotreated at different severity. These samples span a diesel range of from 0.015 to 1.016 wt. % sulfur in diesel fuel. Sulfur was first determined by analysis by a Leco Sulfur Analyzer using ASTM D1552 procedure for high sulfur samples, and for low sulfur samples, sulfur was determined by a Dohrmann sulfur Microcoulometer using analytical procedures of ASTM D3120. These results are listed in Table A under "Lab %". Using the data of Table A, a correlation is developed against the laboratory test data. The NIR absorptions are measured and correlated using the wavelengths of 1620 nm, an analytical waveguide for benzothiophenic sulfur, and 2120 nm, combination band for aromatic and/or sulfur. A correlation "multiple R" of 0.9935 is obtained. That is an excellent correlation and is further confirmed by the regression constant K(0) equalling -0.177, remarkably close to 0, indicating a near absence of analytical interference. Similar results are obtained with diesel fuel, jet fuel, kerosene, lube oil, and FCC feedstock. TABLE A______________________________________NIRSystems Calculated PercentsSpl No. Lab % NIR % Residual______________________________________ 1 1.016 1.006 -.010 2 .243 .225 -.018 3 .172 .160 -.012 4 .089 .085 -.004 5 .051 .035 -.016 6 .023 .038 .015 7 .105 .073 -.032 8 .030 .055 .025 9 .035 .056 .02210 .027 .039 .01211 .255 .276 .02112 .159 .174 .01513 .157 .155 -.00214 .110 .099 -.01115 .079 .057 -.02316 .166 .141 -.02517 .074 .082 .00818 .075 .081 .00619 .078 .086 .00920 .056 .085 .02921 .349 .363 .01422 .236 .271 .03523 .193 .189 -.00424 .139 .155 .01625 .079 .063 -.01626 .201 .169 -.03227 .081 .087 .00628 .078 .084 .00629 .077 .087 .01130 .052 .071 .01931 .235 .219 -.01632 .096 .108 .01233 .074 .068 -.00634 .068 .045 -.02335 .036 -.003 -.03936 .100 .077 -.02337 .030 .035 .00538 .028 .026 -.00339 .023 .027 .00340 .015 .040 .025______________________________________ EXAMPLE 8 (The Invention Using Batch-Type NIR Cells for Sulfur Determination) A diesel fuel sample (6 grams) is separated into high sulfur and low sulfur fractions by passing (@500 ml./minute) the fuel down a silica diamine column connected in series to a silica gel column using hexane as the solvent on a Waters Div. Millipore, Milford, Mass., Model 500A high performance liquid chromatograph. The low sulfur fraction is collected off the end of the column and the hexane mobile phase is removed by rotary evaporation. The high sulfur fraction is then back flushed from the column by reversing the flow and substituting methylene chloride as the solvent. The solvent is again removed by rotary evaporation. The high sulfur and low sulfur fractions are mixed in known proportions to prepare 7 known standards containing 0.023-0.201 wt. % sulfur. The near infrared absorbance spectra of the 7 known standard fractions (or known proportions thereof) are measured on an NIR Systems, Inc., Model 6500 spectrophotometer at 2128 nm using their known concentrations as the dependent variable. Alternatively, we have found it acceptable to substitute a derivative of the absorbance spectra for the absorbance spectra. A plot of the correlation with sulfur versus wavelength is shown in FIG. 9 and the calibration plot (actual sulfur vs. predicted sulfur) is shown in FIG. 10. An equation of the form Y=Mx+b is calculated from Beer-Lambert Law, where Y is the sulfur concentration, X is the samples absorbance at 2128 nm, m is the slope of the regression line, and b is its Y-intercept. A correlation of 0.9999 and a standard error of 0.0011 wt. % sulfur is obtained during the calibration using the Beer-Lambert Law. The absorbances of a series of 39 unknown diesel fuel samples are measured and, using the above equation and the sample's absorbance at 2128 nm, the sulfur concentration of each sample is calculated. Note the near perfect correlation with sulfur content in the preferred bands of the invention for the calibration data. EXAMPLE 9 (Measuring ASTM Color) A series of color standards are prepared by visually matching a series of diesel fuel samples diluted with paraffin oil to the visual color standards used in ASTM D1500 to determine ASTM Color. The colors ranged from 1.0-5.5 in increments of 0.5. The liquid visual standards produced in this manner were correlated against their visible absorbance spectra at 594 and 500 nm. The correlation coefficient obtained was 0.999 with a standard error of 0.075. The agreed quite well with the 0.5 intervals which were determined by the primary test method and gave correct test results when measured on 39 unknown test samples. MODIFICATIONS Specific compositions, methods, or embodiments discussed are intended to be only illustrative of the invention disclosed by this specification. Variation on these compositions, methods, or embodiments are readily apparent to a person of skill in the art based upon the teachings of this specification and are therefore intended to be included as part of the invention disclosed herein. Reference to documents made in the specification is intended to result in such patents or literature being expressly incorporated herein by reference including any patents or other literature references cited within such documents.

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RELATED APPLICATIONS This is a continuation-in-part application of a non-provisional patent application Ser. No. 11/560,922 filed on Nov. 17, 2006 now U.S. Pat. No. 7,717,968 which claims priority to a provisional patent application Ser. No. 60/780,240 filed on Mar. 8, 2006 and incorporated herewith in its entirety. FIELD OF THE INVENTION The subject invention relates to an electrode for a cell of an electrochemical device having improved cell charged capacity, recycling stability, energy and power, method for manufacturing the same. BACKGROUND OF THE INVENTION The term “nanotechnology” generally refers to objects, systems, mechanisms and assemblies smaller than 100 nanometers and larger than 1 nm. In recent years nanotechnology has been used to make products, that is, raw materials are processed and manipulated until the desired product is achieved. In contrast, nanotechnology mimics nature by building a product from the ground up using a basic building block—the atom. In nanotechnology atoms are arranged to create the material needed to create other products. Additionally, nanotechnology allows for making materials stronger and lighter such as carbon nano-tube composite fibers. One of the areas of continuous development and research is an area of energy conversion devices, such as for example secondary batteries capable of charging electricity after discharge and having at least one electrochemical cell. The cell includes a pair of electrodes and an electrolyte disposed between the electrodes. One of the electrodes is called a cathode wherein an active material is reduced during discharge. The other electrode is called an anode wherein another active material is oxidized during discharge. Secondary batteries refer to batteries capable of charging electricity after discharge. Recently, intensive research has been conducted on lithium secondary batteries because of their high voltage and high energy density. The typical lithium battery having an anode containing an active material for releasing lithium ions during discharge. The active material may be metallic lithium and an intercalated material being capable of incorporating lithium between layers. The active material is deposited or coated upon a metal current collector formed from a metal tape to increase electro-conductive characteristics of at least one of the electrodes. Alluding to the above, various methods for deposition of the active materials onto the metal current collector have been used in the prior art applications. One of these methods is physical vapor deposition (PVD), which includes E-beam evaporation, filament evaporation and different sputtering deposition, is currently used to generate thin films on substrates, i.e. the metal current collector. However, this method includes numerous disadvantages, such as, for example, non-time effective deposition rates as relate to coating thickness of the substrate per unit, typically in the range of a few microns per minute. Another method is known as chemical vapor deposition (CVD), including rapid thermal CVD, or RT CVD, results non-time effective deposition of the coating onto the substrate. Sputtering techniques such as RF or DC sputtering, as well as laser evaporation, plasma arc evaporation, electro-spark deposition (ESD), and the like are also known to have low deposition rates. In addition, all of the aforementioned methods are performed by and require expensive vacuum equipment and do not provide strong adhesion of the coating to the substrate, which is detrimental in various applications, particularly in manufacturing electrodes for energy conversion devices, such as batteries. These aforementioned methods are proven to achieve rates of tens of microns per minute. However, if the deposition rates of these methods are increased to higher rates, it may adversely impact adhesion of the coating upon the substrate. As such, these methods are limited to deposition of the coating that results in a range of 10-20 μm per minute, which has limited industrial application, such as to production of a very thin battery of the type used in electronic devices. However, these prior art methods are not cost effective when used in a production of other types of batteries, such as, for example, batteries for vehicles, and the like. Alluding to the above, another method, which used vacuum, was also applied in fabrication of the substances of the electrodes. However, this method had negatively impacted the crystalline composition of the materials deposited upon the substrate. Those skilled in the art will appreciate that a shortage of oxygen in spinel phases leads to transformation of cubic crystal matrix to tetragonal one, which negatively affects electrochemical properties. The usage of carbon as a conductive agent, in some of the prior art applications, presents numerous disadvantages because of the lower electrical conductivity of the carbon as compared to metals, thereby creating additional voltage drop at the interface with the metal current collector. The art is replete with various other methods and apparatuses for forming metal current collector for electrodes of a battery cell, which are disclosed in the United States Patent Publication Application Nos. 20020177032 to Suenaga; 20030203282 to Grugeon; 20040248010 to Kato et al.; and the U.S. Pat. No. 6,761,744 to Tsukamato et al. These aforementioned prior art methods share at least one disadvantage such as the active layer formed on top of the metal current collector of the electrodes to define a space therebetween, which negatively impacts cycleability and possibility to properly function in applications requiring higher C-rate. Another disadvantage of the methods mentioned above that negatively impacts both the life span of the battery and the manufacturing costs associates therewith is the structure of the battery wherein the active layer is formed on the metal current collector and additional binders used as adhesion between the active layer and the metal current collector thereby increasing both the weight and size of the battery, which, as mentioned above, negatively impacts both specific characteristics of the battery and the manufacturing costs associates therewith. Alluding to the above, none of these prior art references teaches the method of forming the electrode which leads to an improved battery having the electrode with accessible porosity sufficient for penetration of electrolyte to contact with particles of the active material, conducting agent should provide contact of active substance particles with current collector. In the normal process of gas dynamic (cold spray) deposition, only metallic particles can be deposited on metallic substrate. The ceramic particles are inculcated in metal collector and do not form the necessary porosity. Introduction of a metal powder into mixture with the ceramic components leads to plastic deformation of metal particles at their collision with ceramic particles. As a result of plastic deformation metal particles create films on ceramic particles of the active substance. The resulting material does not have sufficiently accessible pore structure and is characterized by low mechanic strength. In addition, electric contact of each particle with current collector is not provided. Furthermore, at high deposition energies, metal particles can fuse during collision. In this case, conglomerates are formed. Such conglomerates disturb the uniformity of the deposited material. But even with the aforementioned technique, to the extent it is effective in some respect, there is always a need for an improved processes for engineering of porous electrodes that is light, thin, cost effective, have improved cycle ability, specific energy and power as well as ability to properly function in applications that depend upon higher C-rate and easy to manufacture. SUMMARY OF THE INVENTION A metal current collector of the present invention is formed from a metallic tape used to form a first electrode such as an anode and a second electrode such as cathode combined into a cell for producing electric power without limiting the scope of the present invention. The metal current collector of the first electrode and the second electrode has opposed sides defining an initial thickness. An active core is formed inside the metal current collector. The active core is formed from first particles being integral with and extending from the metal current collector of at least one of the first and second electrodes and second particles formed from material other that the first particles of the metal current collector. The first and second particles connect with one another to form a porous grid of a three dimensional configuration of the active core disposed inside the metal current collector thereby resulting in the metal current collector being integral with the active core and presenting a second thickness. Based on application requirements, the second thickness may be substantially the same or smaller than the first thickness. The active core is mixed with and covered by an electrolyte. A layer of isolating bar is continuously disposed about one of the opposed sides of the metal current collector of at least one of the first and second electrodes. An anode layer is formed from lithium, carbon or other covering the active core to extend co-planarly with the layer of isolating bar. An anode current collector is formed from copper, nickel or other metal to extend over the anode layer and the layer of isolating bar. An isolating layer extends over the anode current collector sandwiched between the anode layer and the isolating layer. An advantage of the present invention is to provide a unique metal current collector of an electrode with integrated active core having a porous structure received by effective deposition of an active material into the metal current collector substrate in a binder free fashion while maintaining outstanding adhesion. Another advantage of the present invention is to provide a current collector wherein an active layer is formed inside the current collector thereby increasing the specific characteristics of the cell. Still another advantage of the present invention is to provide a unique method for fabricating the electrodes wherein the metal current collector presents nano-structured surface at low cost. Still another advantage of the present invention is to provide an electrode material having an improved nano-structure which is utilized as at least cathode or anode of a fuel cell leading to low thermal stability and improved cycling ability. Still another advantage of the present invention is to provide a unique method of forming the inventive electrode structure for the cell by virtue of a unique high-pressure deposition solidification method wherein the particles of active material and solidified drops formed as a result of formation of aerosol mixture form a grid presenting a continuous surface of the metal current collector of the electrode. Still another advantage of the present invention is to provide the metal current collector for the electrode presenting stable operation in a broad range of discharge rates and operating temperatures. Still another advantage of the present invention is to provide high-performance equipment and methodology for high speed deposition of the particle of the active material while suppressing it's possible thermo-chemical degradation. The present inventive concept has various applications including and not limited to high efficiency thin-film photovoltaic solar cells for cost-effective renewable energy, fuel cell components such as catalytic membranes for environmentally friendly power supplies, super capacitors for smaller and lighter portable handheld devices such as cell phones, laptops, thin film sensors for more effective monitoring and control of temperature, illumination, and humidity, high-conductivity wires with low resistance adaptable for manufacturing of a wide variety of electronic devices, and the like. BRIEF DESCRIPTION OF THE DRAWINGS Other advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein: FIG. 1A illustrates cross sectional view of a structure on an inventive metal current collector for electrodes of opposite polarity wherein particles of an active material are represented by crystals or amorphous particles interconnected with a multitude of other particles of circular shape representing accreted and crystallized drops of melted metal current collector; FIG. 1B illustrates a perspective view of the structure of the metal current collector of an electrode of FIG. 1A ; FIG. 2A illustrates is a perspective and segmental view of the metal current collector of the electrode and the first particles colliding therewith thereby melting the metal current collector with some particles partially entering the metal current collector; FIG. 2B is a partially cross sectional view of the electrode having the metal current collector of FIG. 2A ; FIG. 2C illustrates is a perspective and segmental view of the metal current collector and the first particles disposed inside the metal current collector with the areas of local melting of current collector shown in phantom; FIG. 2D is a partially cross sectional view of the metal current collector of FIG. 2C with the first particles shown in phantom; FIG. 2E illustrates is a perspective and segmental view of the metal current collector and the metal drops splashed from the metal current collector as in response to the impact of the first particles against the metal current collector and applying ultrasonic vibration; FIG. 2F is a partially cross sectional view of the electrode of FIG. 2E ; FIG. 2G illustrates is a perspective and segmental view of the metal current collector and the metal drops solidified in the shaped of the second particles and interconnected with the first particles to form a grid of a porous structure of an active core inside the metal current collector; FIG. 2H is a partially cross sectional view of the metal current collector of FIG. 2G ; FIG. 3A illustrates a perspective view of an apparatus for forming the electrode having the metal current collector disposed therein; FIG. 3B illustrated a fragmental view of the apparatus shown in FIG. 3A ; FIGS. 4A through 4E illustrate various cross sectional view of the metal current collector of the present invention as the metal current collector is moved along an assembly path with the active core being formed inside the metal current collector; FIG. 5 shows a schematic vie of the assembly of the cell by combining the electrodes of opposite polarity with each electrode having inventive active core inside the current collector; FIG. 6A illustrate various microscopic views of fracture of the inventive electrode to clearly illustrate the first and second nano-particles of the active core with each of the particles having nano-dimensions; FIG. 6B illustrate the cross section structure of initial aluminum current collector before the active material deposition; FIG. 6C illustrate the cross section structure of the electrode with the active layer deposited inside current collector shown in the FIG. 6B ; FIG. 7 presents a graph illustrating electrochemical testing results of the cell having a cathode electrode formed according to the present invention; FIG. 8A is a perspective view of at least one configuration of the inventive cell; FIGS. 8B and 8C show a microscopic views of the cross section of the thin cell with at least one electrode formed according to present invention; and FIG. 9 presents another graph illustrating electrochemical testing results of the cell having at least one electrode formed according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the Figures, wherein like numerals indicate like or corresponding parts, an electrode of the present invention is generally shown at 10 . The electrode 10 of the present invention is formed from a metallic tape, generally indicated at 11 and shown fragmentally in FIGS. 1A to 2H , is used to form a first electrode such as an anode and a second electrode such as cathode, both illustrated at A and C, respectively, in FIGS. 5 and 8B and 8 C, and spaced by a separator S and combined into a cell, generally indicated at 13 in FIG. 8A , for producing electric power without limiting the scope of the present invention. The metal current collector 11 of the first electrode and the second electrode has opposed sides 12 and 14 defining an initial thickness 16 , as best illustrated in a cross sectional view shown in FIG. 1A . An active core, generally shown at 18 in FIG. 1A , is formed inside the metal current collector 10 . The active core 18 is formed from first particles 20 being integral with and extending from the metal current collector 11 of at least one of the first and second electrodes. The first particles 20 are formed as the second particle 22 , impacting the metal current collector 11 , as best shown in FIGS. 2A and 2B , resulting in local increased temperature of the metal current collector 11 , which locally melts, as shown in FIGS. 2C and 2D , as the second particles 22 are at least partially penetrate the metal current collector 11 . As best illustrated in FIGS. 2E and 2F , the impact of the second particles 22 onto the melted metal current collector 11 results in multitude of aerosol drops 24 separated from the metal current collector 11 , as best illustrated in FIGS. 2E and 2F . The active core 18 is formed in response to solidification of the aerosol drops 24 , which follows local melting and ultrasonic cavitations of the metal current collector 11 thereby forming the first particles 20 . The first particles 20 are integral with the metal current collector and present circular or globular configuration, as view in a cross section. The second particles are formed from of active material, other that the metal current collector 11 , and may present a rectangular configuration, or other configuration, and the like, as best shown in FIGS. 1A and 1B , without limiting the scope of the present invention. The circular configuration of the second particles 22 , as shown in FIGS. 2A through 2H are for illustrative purposes only without intent to limit the scope of the present invention. the active material of the second particles 22 includes and not limited to silicon, carbon, germanium, oxides, salts, ceramic components, LiCoO 2 , LiMn 2 O 4 , LiFePO 4 , MnO 2 , Li, Si, C, Ge, SnO, SnO 2 , and the like, without limiting the scope of the present invention. The first and second particles 20 and 22 are connected with one another to form a porous grid, generally indicated at 32 in FIGS. 1A and 1B of a three dimensional configuration of the active core 18 disposed inside the metal current collector 11 thereby resulting in the metal current collector 11 being integral with the active core 18 and presenting a second thickness 34 . The grid 32 is further defined by the first particles 20 being continuously connected with the metal current collector 11 thereby eliminating sharp interface between the grid 32 and the metal current collector 11 . The first particles 20 are connected to the second particles 22 and the metal current collector 11 in a diffusible fashion with the second particles 22 being at least partially exposed through and beyond the grid 32 . Alternatively, the second particles 22 are inside the grid 32 of the active core 18 and do not exposed beyond the active core 18 . The first particles 20 and the second particles 22 are free from low conductivity films at interface defined between the first and second particles 20 and 22 and the metal current collector 11 . The first particles 20 are fused with one and the other thereby forming an inter-layered structure of the grid 32 with the second particles 22 disposed therebetween. The second particles 22 and the metal current collector 11 define points of contacts having a thermal decomposition temperature being lower than a melting temperature of the first particles 20 . The second particles 22 present a size ranging from at least 50 nm and up to 500 nm. The first particles 20 present a size ranging from at least 5 nm and up to 100 nm. Based on application requirements, the second thickness 34 may be substantially the same or smaller than the first thickness 16 . The grid 32 presents a plurality of pores, only some of the pores are shown at 36 in FIG. 1A . The grid 32 may present 60 percent of the pores 36 and 40 percent of the first and second particles 20 and 22 of a total volume of the active core 18 . This ratio is not intended to limit the scope of the present invention. The pores 36 may present up to 80 percent of the active core 18 or only 0.55 percent of the active core 18 . This ratio is not intended to limit the scope of the present invention. The active core 18 is mixed with and covered by an electrolyte, as best shown at 38 in FIG. 4C . The electrolyte 38 may be liquid or non-liquid. Alluding to the above, one of the advantages of the present invention is the absence of an oxide film at contact points the first and second particles 20 and 22 , which reduces electronic resistance at the interface of the cathode's C active substance and metal binding. Multitude of contact points defined between the particles 20 and 22 and the metal current collector 11 expose the greater part of the active core 18 open to electrochemical interaction with the electrolyte. The size of the first particles 20 as viewed in cross section is between 5 to 100 nm. The size of the second particles 22 formed from the active substance is between 50 to 500 nm. Based on the results conducted by the applicant through a quantitative electron-microscopic inspection, the average number of contacts of the metal, i.e. the first particles 20 and the metal current collector 10 with the second particles 22 of the active material is 25-32 per square micron of particle surface, thereby providing reliable and improved outlet of electrons to the metal current collector 10 during cyclic changes in active substance particle size during reversible electrode operation in the cell 13 . In some applications of the present invention the three-dimensional grid 32 has low thickness and the second particles 22 of form the dense one layer film on the electrode surface. FIGS. 3A and 3B illustrate fragmental view of the inventive apparatus 40 of the present invention, which is described in great details in the patent application serial number incorporated herewith in its entirety. FIGS. 3A and 3B illustrate a nozzle 42 through which the second particles 22 of the active material are injected onto the tape 44 of the electrode 10 rolled between a pair of rollers 46 and 48 . An ultrasonic vibrator, generally shown at 45 in FIGS. 3A and 3B , is positioned to abut the inner side of the tape 44 . The functional aspects and purpose of the ultrasonic vibrator 45 are disclosed in the patent application Ser. No. 11/560,922 incorporated herewith by reference in its entirety. A brush 50 is positioned adjacent the tape 44 to extract excess of the first and second particles 20 and 22 . FIGS. 4A through 4E illustrate various cross sectional view of the electrode 10 of the present invention as the metal current collector 11 is moved along an assembly path with the active core 18 being formed inside the metal current collector 11 . As the active core 18 is formed inside the metal current collector 11 , as described above, and is filled and/or mixed with the electrolyte 38 , a layer of isolating bar 60 is continuously disposed about one of the opposed sides 12 of the electrode 10 of at least one of the first and second electrodes. In one embodiment, the electrode 10 can be an anode and can also include an anode layer 62 formed from lithium covering the active core 18 to extend co-planarly with the layer of isolating bar 60 . In such an embodiment, an anode current collector 64 formed from copper, nickel or other metal can extend over the anode layer 62 and the layer of the isolating bar 60 . An isolating layer 66 extends over the anode current collector 64 sandwiched between the anode layer 62 and the isolating layer 66 . The structure of the electrode 10 as set forth above is applicable to both the anode A and the cathode C of the present invention. FIGS. 8B and 8C illustrate a cross section of the cell includes the anode A and the cathode C formed by the method of the present invention, clearly illustrating the dimensions of the anode A of 15 μm, the cathode of 9 μm, and the separator S of 10 μm. The table shown further below illustrates dimensions and technical characteristics of the preferred embodiment of the cell 13 of the present invention. However, these dimensions are illustrated for exemplary purposes as one of the embodiment of the present invention and are not intended to limit the scope of the present invention. Cathode - Al current collector Thickness, μm 9 with active substance LiMn2O4 Δm, mg/cm 2 0.7-0.9 Separator + polymer electrolyte Thickness, μm 10-16 Anode - Cu current collector with Li Thickness, μm 15 Total of battery Expectancy 40 Thickness, μm Real Thickness, μm 50 See Ris. 2. Capacity, mAh/cm2 0.07-0.09 at low current Volume, cm 3 0.01 Capacity, mAh at 0.18 low current discharge Average voltage, 3.9 V at low current discharge Energy density Wh/l 70 Peak Power W/l >500 As best illustrated in FIG. 5 an assembly “roll to roll” process of the present invention is generally shown at 68 . The cathode C and the anode A are rolled from two spaced drums 70 and 72 along an assembly path 74 with the metal current collector 10 of each of the cathode C and the anode A facing one another. An electrolyte with separator (if necessary) 76 , either liquid or non-liquid is injected between the cathode C and the anode A in addition to the electrolyte 38 of the metal current collector 10 . A heating element (not shown) is adjacent the assembly path 74 to heat the electrolyte 76 thereby improving polymerization of the electrolyte 76 . After the cathode c and the anode A are sealed 80 a pair of cutting devices 82 and 84 disposed on both sides of the assembly path 74 are cutting the assembled cathode C and the anode A to a multitude of prefabricated cells 13 . Numerous mechanical, laser, and electrical devices are used as cutting devices 82 and 84 and are not intended to limit the scope of the present invention. The cells 13 are sealed hermetically along the peripheral edge or the periphery 86 . FIGS. 6A through 6C illustrate various cross section microscopic views to clearly illustrate the first and second nano-particles 20 and 22 of the active core 18 with each of the particles having nano-dimensions. FIG. 7 presents a graph illustrating electrochemical testing results of cathode electrode 10 formed according to the invention. FIG. 8A is a perspective view of at least one configuration of the inventive cell. FIGS. 8B and 8C show cross section microscopic views of the electrodes of opposite polarity with at least one electrode formed according to the invention. FIG. 9 presents another graph illustrating electrochemical testing results of the cell shown in the FIGS. 8 A-C having at least one electrode made according to the present invention. Alluding to the above, the electrode 10 and the method of forming the same have numerous valuable advantages of the prior art electrodes and methods. One of the advantages, for example, is the unique structure of the electrode 10 wherein the active core 18 is formed in an organic binder free fashion, i.e. by the inventive method of solidification of the aerosol drops 24 of the metal current collector 10 and the particles 22 of active material while maintaining adhesion therebetween. Another advantage of the present invention is to provide a unique method for fabricating the electrodes A and/or C wherein the metal current collector 10 presents nano-structured surface, has low thermal stability and improved cycling life. The unique method of forming the electrodes A and/or C utilizes the high-pressure deposition solidification method wherein the particles 22 of the active material and the solidified drops 24 are formed as a result of the formation of the aerosol mixture form the grid 32 presenting a continuous surface of the metal current collector 10 of the electrodes A and/or C. The present inventive concept has various applications including and not limited to high efficiency thin-film photovoltaic solar cells for cost-effective renewable energy, fuel cell components such as catalytic membranes for environmentally friendly power supplies, super capacitors for smaller and lighter portable handheld devices such as cell phones, laptops, thin film sensors for more effective monitoring and control of temperature, illumination, and humidity, high-conductivity wires with low resistance adaptable for manufacturing of a wide variety of electronic devices, and the like. While the invention has been described with reference to an exemplary embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coin wrapping machine, and particularly to a coin accumulator assembly for use in the coin wrapping machine. In the typical coin wrapping machine, coins are fed on a rotary disk and then guided to a coin guide passage one by one. While being passed through the coin guide passage, the coins are counted. The coins, after being counted, are conveyed by a conveyor belt to a coin accumulator tube through a chute. The coin accumulator tube may have a height for accommodating a predetermined number of thickest coins and means for adjusting the operational height adapted to receive a pre-set number of coins. Alternatively, a coin accumulator tube which is adapted to receive a predetermined number of coins of pre-set species or kind is selected from a group of coin accumulator tubes each being adapted to accumulate coins of individual species, and assembled in operational position. In either case, coins are stacked on a shutter plate provided at the bottom of the coin accumulator tube to form a stack of coins. After the predetermined number of coins has been accumulated in the tube, the shutter plate is opened and the stacked coins are discharged from the tube and carried by a carrier bar positioned just beneath the shutter plate to be moved to a wrapping station. 2. Prior Art In the conventional assembly, since no means for effecting stepwise accumulation of coins is not associated in the coin accumulator tube, coins fed from the chute to the accumulator tube are allowed to fall down in the vertical direction under the action of gravitational force. During this falling movement, each coins is not always maintained horizontally but is swayed or inclined randomly. Partly by this random movement and partly by an irregular bounding action, there is a possibility for some of the coins to be stacked in disorder, for instance, any one of the coins being overlaid on the preceding coin in an inclined condition. If such a disorder occurs, the coin stack cannot be subjected to the subsequent wrapping operation and must be removed from the wrapping machine, leading to reduction in performance efficiency of the machine. Moreover, some means for detecting the occurrence of such disorder must be provided. SUMMARY AND OBJECT OF THE INVENTION The primary object of the invention is to provide a coin accumulator tube provided with means for effecting stepwise accumulation of coins. According to one embodiment of the invention, said means for effecting stepwise accumulation of coins includes a support member for supporting the shutter and having a threaded hole, a screw shaft thrusted through the threaded hole, a driving system including a reversible motor for rotating the screw shaft, and a guide rod to be slidably engaged with the support member for preventing the latter from being rotated but for guiding the same in the downward direction when the screw shaft is rotated by the driving system. According to further embodiments of the invention, the aforementioned combination of the screw shaft, the threaded hole and the guide bar may be replaced by a rack-and-pinion system or a combination of a swingable arm and a cam plate associated with suitable driving means. A further object of the invention is to provide a system for controlling the coin accumulator assembly in accordance with a suitable sequential control program. DESCRIPTION OF THE DRAWINGS The features and advantages of the present invention will become apparent from the following detailed description of the presently preferred embodiments of the invention with reference to the drawings, in which: FIG. 1 is an exploded view showing main portions of an embodiment of the invention; FIG. 2 is a plan view showing a portion of the coin guide passage and the coin accumulator tube according to the invention; FIG. 3 is a sectional view showing the outline of a coin accumulator tube embodying the invention; FIG. 4 is a sectional view taken along the line IV--IV of FIG. 3; FIG. 5 is a sectional view similar to FIG. 3 but showing another embodiment of the invention; FIG. 6 is a block diagram showing a control system for controlling the operation of the embodiment shown in FIG. 1; FIG. 7 shows how flow charts 7A and 7B go together to form a flow chart showing the sequential control program for controlling the embodiment shown in FIG. 1; FIG. 8 is a diagram showing a control circuit associated with the embodiment shown in FIG. 1; FIG. 9 is a block diagram showing another control system; FIG. 10 shows how flow charts 10A and 10B go together to form a flow chart showing the sequential control program in accordance with the block diagram of FIG. 9; and FIG. 11 is a diagram showing a control circuit for instructing the sequential control operations shown in FIG. 10. DESCRIPTION OF PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the appended drawings showing preferred embodiments of the invention. Firstly referring to FIGS. 1 to 4, coins are successively fed to a coin guide passage 1 and conveyed through the passage by a conveyor belt 2. The coin guide passage 1 is provided with means for rejecting coins of different species, for example a coin rejection hole or slot 3, sensors for detecting the passage of coins comprising photoelectric elements 4 and 4, a stopper 5 for stopping passage of coins after a pre-set number of coins has been passed to a coin accumulator tube 7 and adapted to rotate to a normal position for allowing the coins to pass in response to a signal for instructing to start the next cycle operation, and another conveyer belt 6 moving at a relatively higher speed than the conveyor belt 2 so as to increase the gaps between adjacent coins. A coin accumulator tube, designated by numeral 7, has a hollow cavity 7' in which coins are accumulated. The diameter of the cavity 7' may be varied in accordance with the diameter of coins to be accumulated therein, or a coin accumulator tube having a cavity for snugly receiving coins of single species may be selected from a group of accumulator tubes to be assembled in the system. A coin reception recess 7" is formed on the top of the coin accumulator tube 7. The coin accumulator tube 7 is assembled such that the top face of the coin reception recess 7" is flush with the guide face of the coin guide passage 1 or positioned at the level slightly lower than the latter. A vertically-extending slit 8 is cut through the peripheral wall of the tube 7, and a circumferential slit 9 is formed at the lower portion of the cylindrical tube 7. A radial through-hole 10 for an upper photoelectric sensor 10' for sensing the height of accumulated coins is provided at the upper portion of the tube 7. Another radial through-hole 11 for a lower photoelectric sensor 11' for detecting the presence of a carrier bar 12 (see FIG. 3) is provided at the lower portion of the tube 7. A movable shutter mechanism b is associated with the coin accumulator tube 7. The movable shutter mechanism b of this embodiment comprises shutter plates 13 and 13' each having a generally semicircular free end, an elongated stem portion and a generally trapezoidal base portion. In the normal closed position, both shutter plates 13 and 13' engage with each other with their free ends forming a generally circular shutter which is inserted in the cavity of the coin accumulator tube 7 to form the bottom thereof and to support the accumulated coins until a pre-set number of coins is stacked in the tube 7. The base portions of the shutter plates 13 and 13' are pivoted by pins 15 and 15' of a support member 14 and moved by rollers 16 and 16' mounted on lugs of the base portions to open or close the shutter formed by the generally semicircular free ends of the shutter plates 13 and 13'. An operation pin 17 is mounted to another lug of the base portion of the one shutter plate 13'. The support member 14 has a threaded hole for engaging with a screw shaft 18 and another hole through which a guide rod 19 extends to prevent the support member 14 from rotating. The screw shaft 18 is rotated by a driving system 30 to lower or raise the support member 14. When the support member 14 is lowered to the lowermost position, the operation pin 17 engages with a hole 21 of an operating lever 22. The operating lever 23 is connected to a solenoid 23. Referring now to FIG. 3, the lower movement of the shutter plates 13 and 13' which is controlled on the basis of the output signal generated from the upper photoelectric sensor 10' will be first explained. At the beginning of the accumulation operation, in order to raise the support member 14 to its uppermost position, as shown in dot- and dash line, a reversible motor 25 is actuated to rotate the screw shaft 18 in a reverse direction. When the support member 14 reaches the uppermost position, a cam 24 mounted to the support member 14 engages with an actuator of a limit switch A to switch-off the limit switch A thereby to stop the motor 25. In the state, the shutter plates 13 and 13' are closed and supported at a level slightly lower than the top face of the recess 7" of the coin accumulator tube 7. Coins a are successively fed by a conveyer belt 2 and the gaps therebetween are increased by the action of the high speed conveyer belt 6. The coins are then passed through the recess 7" to be placed on the shutter plates 13 and 13'. Since the difference in height between the top face of the recess 7" and the shutter plates 13 and 13' is small, the distance of falling movement of individual coins within the hollow cavity 7' of the tube 7 is limited. As coins a are stacked on the shutter plates 13 and 13' and the through-hole 10 is shielded by the accumulated coin pile, a signal is generated to actuate the reversible motor 25 to rotate the same in the forward direction, whereby the screw shaft 18 is rotated through the driving system 20 in the direction to lower the support member 14. The lowering speed of the support member can be controlled by detection, by the sensor 10', of the coins accumulated in the accumulator tube or by the combination of the pitch of the screw and the rotational speed of the shaft 18, so that the shutter mechanism is lowered in synchronized with the coin feeding rate. The shutter mechanism is thus lowered stepwisely or continuously while maintaining the distance between the top face of the lastly stacked coin and the top face of the recess 7" at a small limited value. Coins a fed to the accumulator tube 7 are counted by the counting elements 4 as described before, and when the counted number reaches the pre-set number, the stopper 5 is rotated to interrupt the coin flow in the coin guide passage 1 to stop coin supply. At that time, the shutter plates 13 and 13' are lowered to the lowermost position, shown by the solid line in FIG. 3, to be aligned with the circumferential slit 9. In the meanwhile, the tube 7 may have a height such that the shutter plates 13 and 13' clear the bottom peripheral face thereof when the pre-set number of coins is stacked thereon and the shutter plates 13 and 13' reach their lowermost position. In such a case, the circumferential slit 9 may be dispensed with. Anyway, when the shutter plates 13 and 13' are lowered to the lowermost position, the cam 24 depresses the actuator of a limit switch B to stop the reversible motor 25 and the carrier bar 12 is raised beneath the shutter plates 13 and 13' to be ready for receiving the coin pile. When the lower through-hole 11 is shielded by the thus raised carrier bar 12, a signal is generated from the lower photoelectric sensor 11' for energizing the solenoid 23, whereupon the operating lever 22 is drawn or retracted by the solenoid 23 with its hole 22 receiving the operating pin 17 to swing the base portions of the shutter plates 13 and 13'. As the result of these swinging movements of the base portions, the shutter plates 13 and 13' are opened to pass the stack of coins accumulated thereon to the carrier bar 12. The coin stack is then carried by the carrier bar 12 to be moved to a wrapping station (not shown). The shutter plates 13 and 13' are kept open until the top face of the uppermost coin clears the level of the through-hole 11, since the hole 11 is shielded by the descending coin stack until then. When the coin stack clears the level of the through-hole 11, the solenoid 23 is deenergized and the operating lever 22 is returned back to the normal extended position, whereby the shutter plates 13 and 13' are swinged back to the closed position. Then, the reversible motor 25 is actuated to rotate the screw shaft 18 in the reverse direction to raise the shutter mechanism b to the uppermost position to be ready for the next cycle operation. Although not specifically shown, the screw shaft 18 may be replaced by a rack which is meshed with a pinion rotated by a suitable motor mounted on the support member 14. A further modified arrangement is shown in FIG. 5, which comprises a swingable arm 26 having one end engaging with the support member 14. The arm 26 is swinged by a roller 28 mounted on a rotatable cam plate 27 to lower or raise the support member 14. The limit switches A and B are also operated by the cam plate 27 to be brought to the on or off position. There is provided means for controlling the swinging movement of the arm 26 thereby to lower the support member 14 from the uppermost position to the lowermost position at a substantially constant speed. Such means include an electric circuit for controlling the rotating speed of the motor by changing the pulse number depending on the number of counted coins, and a servo or pulse (step) motor assembled in place of the reversible motor 25. The control of the above mentioned movable shutter mechanism b will be now explained. As a first embodiment, the control system which is made by utilizing the outputs from the upper photoelectric sensor 10' (hereinafter referred to as an upper photo) associated with the through-hole 10 will be first explained. This control system is based on the idea that if the counted coins are detected by the upper photo, it is clear that the counted coins are stacked at least up to the position where the upper photo is located or the height of the upper photo. In such a case, the shutter plates 13 and 13' are lowered until the coins are not detected by the upper photo. FIG. 6 diagrammatically shows the above-mentioned control in a block diagram. The upper and lower photos 10' and 11' are actuated by the coins a; by these photos 10' and 11', and the upper and lower limit switches A and B, the motor 25 and the solenoid 23 are electrically actuated; and by the motor 25 and the solenoid 23, the movable shutter mechanism b is mechanically actuated. In turn, by the movable shutter mechanism 6, the coin a and the upper and lower limit switches A and B are mechanically actuated. FIG. 7 is a flow-chart for explaining a sequence of operations of the above-mentioned control system and FIG. 8 shows its embodied circuit. The circuit of FIG. 8 will be explained with reference to the flow chart of FIG. 7. To a terminal 801, the H level of a pulse signal is put in by a start operation (which corresponds to start 701 of the flow chart of FIG. 7; only numerals will be indicated hereinafter) and the signal is put in a set terminal S of a flip-flop FF1 through an OR gate OR1. Furthermore, the flip-flop FF1 is provided for memorizing a condition that the shutter plates 13 and 13' should be returned to their initial position. The H level signal is put out from the output terminal Q of the flip-flop FF1 and is put in an AND gate AND1. At another input terminals of the AND gate AND1, a signal which is turned to the H level when the limit switch A is turned on is put in from a terminal 803 through an inverter INV1, and in addition, a signal which is turned to the H level when the upper photo 10' detects a certain coins a is put in from a terminal 804 through an inverter INV2. For this, the output of the AND gate AND1 maintains the H level from the time when the flip-flop FF1 is set until the time when the limit switch A is turned on, and this signal of the H level output of the AND gate AND1 is given to the motor 25 as a reverse rotation signal through a buffer amplifier BA1 and a terminal 809 (702, 703 of FIG. 7) to raise the shutter plates 13 and 13' of the movable shutter mechanism b to their initial position. In such a case, if there are coins a on the shutter plates 13 and 13', the shutter plates cannot be raised to their initial position. Therefore, if any coin is detected by the upper photo 10', the output of the inverter INV2 is turned to the L level to make the output of AND gate AND1 to be at the L level, for safety. When the shutter plates 13 and 13' are raised to the initial position, the limit switch is turned on and, therefore an H level signal is put in at a terminal 803. This H level signal causes the output of the reverse rotation signal (put out from the terminal 809) to be stopped and at the same time resets the flip-flop FF1 since the signal is put in at a reset terminal R of the flip-flop FF1 (703, 704 of FIG. 7). Furthermore, the signal which is put in at the terminal 803 is also put in an AND gate AND2 at one terminal thereof and at the other terminal, a start hold signal is put in. This start hold signal is one which is maintained to be at an H level from the time when the start operation (701 of FIG. 7) is made to the time when the operation is ended, for example, by a stop operation or an actuation of an automatic stop mechanism due to detection of nonpresence of coins (728, 729 of FIG. 7). The output of the AND gate AND2 is put in at a set terminal of a flip-flop FF2, and the output from the output Q of the flip-flop FF2 is fed as a coin transfer signal to a motor, not shown, for driving the conveyor belt 2, through a buffer amplifier BA2 from a terminal 810. Consequently, as soon as the shutter plates 13 and 13' return to their initial position, the flip-flop FF2 is caused to be set to start the transfer of the coins (705 of FIG. 7). Furthermore, at the reset terminal R of the flip-flop FF2, a count end signal which is turned to the H level when the coins a reaches predetermined number (or wrapping number) is put in from a terminal 805 and the flip-flop FF2 is reset so as to stop the transfer of the coins a at the time of the count end. In a meanwhile, attendent on the transfer and accumulation of the coins, the coins a are detected by the upper photo 10'. The detection signal of the upper photo 10' is put in an AND gate AND3 through a fall edge delay circuit ND and an OR gate OR2. At the other input terminal of the OR gate OR2, the signal from the output terminal Q of a flip-flop FF3 is put in the flip-flop FF3 puts out its H level signal when the count end signal put in from the terminal 805 is put in at the set terminal of the flip-flop FF3 and puts out its L level signal when a shutter plate closing signal, hereinafter described, is put in at the reset terminal R of the flip-flop FF3. Furthermore, at the other input terminal of the aforementioned AND gate AND3, a signal which is turned to the H level when the limit switch B for detecting the shutter plates 13 and 13' being lowered up to their open position is turned on, is put in through an inverter INV3 through from a terminal 806. The output of the aforementioned AND gate AND3 is fed to the motor 25 as a forward rotation signal through a buffer amplifier BA3 from a terminal 811. When the coin a is detected by the upper photo 10', an H level singal is put in at the fall edge delay circuit ND (706 of FIG. 7). This H level signal is put in the AND gate AND3 through the OR gate OR2. In a meanwhile, since the counting operation has been just started, the flip-flop FF3 is maintained to be reset and since the shutter plates 13 and 13' is not in the open position, an L level signal is supplied to the terminal 806. This L level signal is put in the AND gate AND3 as a H level signal through the inverter INV3. For this, an H level signal is put out from the AND gate AND3 to issue the forward rotation signal from the terminal 811 (707 of FIG. 7). While the coins a are successively transferred, counted and accumulated, the detection signals by the upper photo 10' are intermittently put out at a very short interval. For this, if the forward rotation signals put out from the terminal 811 are intermittently put out at a very short interval, such intermittent output are not suitable for the motor 25. In order to avoid these intermittent outputs, the fall edge delay circuit ND is provided for absorbing the intermittent condition and putting out a smoothed or continuous forward rotation signal as a whole. Consequently, when the coins a are successively accumulated and detected by the upper photo 10', the motor 25 is caused to continue its forward rotation and if the coins a are intermittently detected beyond a predetermined interval, the motor 25 is caused to be stopped at each time of detection (708, 709, 710 of FIG. 7). Thus, mainly, the motor 25 is controlled by the detection signals of the upper photo 10' until the shutter plates 13 and 13' reach their open position to make the limit switch on and thereby putting the L level signal from the inverter INV3 in the AND gate AND3. In other words, in case where the coins a are successively accumulated, before the shutter plates 13 and 13' reach the open position, the count operation is ended. At the time, the H level of the count end signal is put in from the terminal 805 at the reset terminal R of the flip-flop FF2 and the set terminal S of the flip-flop FF3. The resetting of the flip-flop FF2 causes the transfer of the coins a to be stopped (712, 713 of FIG. 7). On the other hand, the flip-flop FF3 is caused to be set. The flip-flop FF3 is provided for automatically lowering the shutter plates 13 and 13' up to the open position, regardless of the condition of the detection signal of the upper photo 10' in case where the count operation is ended before the shutter plates 13 and 13' reach the open position. When the flip-flop FF3 is set, the H level signal is fed from its output terminal Q to the AND gate AND3 through the OR gate OR2 to continue to put out the forward rotation signal until the limit switch B is turned on. On the other hand, in case where the coins a are intermittently accumulated, there is a possibility that the shutter plates 13 and 13' reach the open position before the end of count. In such a case, the limit switch B is turned on and an H level signal is put in from the terminal 806, inverted into a L level signal through the inverter INV3 and then put in the AND gate AND3. Consequently, thereafter the forward rotational signal is not put out from the terminal 811 (711, 717 of FIG. 7). In this state, the shutter plates 13 and 13' are stand-by until the count end and at the time of the count end, the transfer of the coins a is stopped in a similar manner mentioned above (718, 719 of FIG. 7). In either case of the above, at the time when the coin count is ended, a signal for starting a wrapping operation is put out by a conventional control, not shown. Then, the carrier bar 12 starts to be upwardly moved toward the shutter plates 13 and 13' up to just below the same in order to receive the coins a accumulated in the tube 7 and transfer the same to a wrapping mechanism, not shown. When the carrier bar 12 is moved just below the shutter plate 13 and 13' in open position, the shutter plates 13 and 13' are opened to transfer the accumulated coins a onto the carrier bar 12. More particularly, when the lower photo 11' detects the carrier bar 12 and the transferred coins a to put out a detection signal, the detection signal is put in an AND gate AND4 from an terminal 807. At the other terminals of the AND gate AND4, the signal from the output terminal Q of the flip-flop FF3 and the detection signal from the limit signal B are put in. Then, the output signal of the AND gate AND4 is put out as a shutter plate open signal to the solenoid 23 through buffer amplifier BA4 from a terminal 812 and simultaneously put in a fall edge detection circuit NDF. This fall edge detection circuit NDF puts out an H level pulse signal by detecting the time when an input signal is fallen from H level to L level and the output signal is fed to the OR gate 1 and the reset terminal R of the flip-flop FF3 as a shutter closing signal showing that the shutter plate open signal is not put out from the terminal 812. Under a condition that the count end signal is put out, that is, the H level signal is put out from the output terminal Q of the flip-flop FF3, and when the limit switch B is on, as the carrier bar 12 is detected by the lower photo 11', the H level signal is put out from the AND gate AND4 to be fed as the shutter plate open signal to the solenoid 23 from the terminal 812 (720, 721 of FIG. 7). Thus, the accumulated coins a are dropped on the carrier bar 12 from the shutter plates 13 and 13'. Thereafter, when the carrier bar 12 is started to be lowered so as to transfer the coins a to the wrapping mechanism, not shown, the lower plate 11' continues to detect the carrier bar 12 and the accumulated coins. When the carrier bar 12 is further lowered and then the accumulated coins a are not detected, since the H level signal is put in at the terminal 807, the H level of the shutter plate open signal is not put out from the terminal 812 (722, 723 of FIG. 7). For this, due to deenergization of the solenoid 23, the shutter plates 13 and 13' are closed by an action of the spring. On the other hand, when the shutter plate open signal is not put out, the H level of pulse signal is put in the set terminal S of the flip-flop FF1 and the reset terminal R of the flip-flop FF3 from the fall edge detection circuit NDF. Then, when the flip-flop FF1 is set, the shutter plates 13 and 13' are actuated to be returned to the initial position (724-726 of FIG. 7) in a similar manner to initial operations at the starting time (701-704 of FIG. 7). Furthermore, by the resetting of the flip-flop FF3, the forward rotation signal is inhibited not to be put out to the motor 25 from the terminal 811 even when the shutter plates 13 and 13' are moved from the open position. Furthermore, when all operations for the coin a are ended, the H level of the start hold signal which has been supplied to the terminal 802 is reset (727-729 of FIG. 7). Moreover, in case where a step motion or a pulse motor may be used as the motor 25 in order to perform a reliable position control of the shutter plates 13 and 13', the outputs of the AND gates AND1 and AND3 may be put in AND gate AND5 and AND6, respectively, and at the other input terminals of the AND gates AND5 and AND6, the pulse signal may be put in from the terminal 808, as shown in dotted lines of FIG. 8. Each output of two AND gates AND5 and AND6 may be fed to the motor as the reverse rotation signal or the forward rotation signal through each buffer amplifier BA5, BA6 from each terminal 813, 814. As a second embodiment, the control system which utilizes the outputs of the counter elements 4 provided for counting the number of the coins a will be explained. This control system is based on the idea that from the counted number of the coins a counted by the counting elements 4, the accumulated height of the coins a accumulated in the tube can be calculated since a specific kind of the coins to be counted is preset and, therefore, the thickness of the one coin can be found. In the case, the shutter plates 13 and 13' are lowered in accordance with the accumulated height of the coins a corresponding to the number of the accumulated coins a. FIG. 9 diagrammatically shows the above-mentioned control in a block diagram. The coin kind signal which is issued from a coin kind setting switch 901 associated with coin kind setting means, such as a dial or a button switch, not shown for selecting a specific kind of coins to be counted, is put in a pulse member setting circuit 902. The pulse number setting circuit 902 determines a pulse number per one number of coin corresponding to the selected kind of the coins and feeds a pulse number signal to a pulse generator 902. The pulse generator 903 feeds pulses per one number of coin to the step motor 25 through a driver D each time when it receives a count pulse from count elements 4. Then, the movable shutter mechanism b is driven by the step motor 25. Consequently, the shutter plates 13 and 13' are caused to be lowered by the height corresponding to the number of the accumulated coins a. Furthermore, the pulse generator 903 is operated by the limit switches A and B which are actuated by the movable shutter mechanism b, and the lower photo 11' for detecting the transfer of the accumulated coins a by the carrier bar 12 so as to move the shutter plates 13 and 13' to the initial position or the open position. FIG. 10 is a flow-chart from explaining a sequence of operations of the above control system and FIG. 11 shows its embodied circuit. Since the main portions of the circuit elements shown in FIG. 11 are similar to these of FIG. 8, the different points will be explained mainly. Relationship among the coin kind setting switch 901, the pulse number setting circuit 902 and the pulse generator 903 is mentioned above, and in the illustrated embodiment, there are six kinds of coins and four kinds of coin thickness (the pulse numbers n 1 , n 2 , n 3 , n 4 ). The pulse generator 903 receives four pulse number signals representative of the coin thicknesses at its terminals n 1 , n 2 , n 3 and n 4 . The pulse generator 903 also receives the reverse rotation signal put out from the AND gate AND1 at its terminal R, receives a coin signal put out from the AND gate AND3 at its terminal F, and receives the forward rotation signal put out from the AND gate AND4. In addition, the pulse generator 903 further receives a drive signal put out from the OR gate OR2 when either one of these reverse rotation signal, coin signal and forward rotation signal are put in the OR gate OR2. In accordance with combination of the above-mentioned input signals, the pulse generator 903 feeds a reverse rotation drive signal from its terminal RD or a forward rotation drive signal from its terminal FD, respectively, through the driver D from a terminal 1111 or 1112. The reverse rotation signal put out from the AND gate AND1 is put out in a similar manner to that of the first embodiment, and similarly the coin transfer signal put out from a terminal 1109 and the shutter plate open signal put out from a terminal 1110 are also constructed in a similar manner to those of the first embodiment. That is, the pulse signal by the start operation, the start hold signal, the signal by ON operation of the limit switch A, the detection signal of the upper photo 10', the count end signal, the signal by ON operation of the limit switches 13, and the detection signal of the lower photo 11' are put in at terminals 1101, 1102, 1103, 1104, 1106, 1107 and 1108, respectively. From each terminals, these signals are put in a group of gates constructed in a similar manner to those of the first embodiments. Therefore, detailed explanations on functions of the gates will be omitted. In case where the lowering of the shutter plates 13 and 13' is controlled by the number of the coins a, the count is always ended before the shutter plates 13 and 13' reach the open position. Therefore it is necessary to drive the step motor 25 until the shutter plates 13 and 13' reaches the open position. Then, the drive by the count elements and the drive after the count end must be controlled, which will be explained. At the terminal 1105, the coin count signal from the count elements 4 is put in, and this signal is fed to the AND gate AND3 at one terminal thereof through the delay circuit TD. Furthermore, the delay circuit TD is provided in view of the transfer period of the coins from count element position to accumulator tube position. At the other terminal of the AND gate AND3, the signal by ON operation of the limit switch B which is put in from the terminal 1107 is put in through the inverter INV3 and while the coin count signal is put in the AND gate AND3, the limit switch B is usually not actuated. Therefore, as mentioned above, each coin signal per each coin is put in at the terminal F of the pulse generator 903 from the AND gate AND3 and the drive signal is put in at the terminal D of the pulse generator 903 through the OR gate OR2 so as to issue a predetermined pulse number (either one of n 1 , n 2 , n 3 and n 4 ) of the forward rotation drive signal per each coin from the terminal FD (1008-1011 of FIG. 10). The output terminal Q of the flip-flop FF3 which memorizes the count end condition by receiving the count end signal from the terminal 1106 is connected to one input terminal of the AND gate AND4, and at the other input terminal, the signal by ON operation of the limit switch B is put in through the inverter INV3 from the terminal 806. Consequently, when a predetermined number of the coins a, the flip-flop FF3 is set and, thereby the forward rotation signal for moving the shutter plates 13 and 13' to the open position is put in at the terminal FF of the pulse generator 903 from the AND gate AND4. The pulse generator 903 continues to put out the forward rotation drive signal from the terminal FD until the forward rotation signal put in from the terminal FF disappears. Thus, the step motor 25 is actuated to move the shutter plates 13 and 13' to the open position (1011-1016 of FIG. 10). The second embodiment can allow the fall distance of each coin in the accumulator tube to be maintained to be a minimum, comparing with the first embodiment.

4y

BACKGROUND OF THE INVENTION The present invention relates to a gruel cooker for microwave ranges, and more particularly relates to a cooking device suited for preparation of rice gruel in microwave ranges. In the conventional way of preparing rice gruel, rice and extra amount of water are mixed together and boiled in a pot rather slowly so that the rice should uniformly absorb the water during slow boiling. When this mixing ratio of water with rice is employed for cooking in a microwave range, quick boiling causes overflow of boiled water out of the pan. As a consequence, rice particles circulate in the water bath only and boiled rice particles include hard cores which mar relish of the obtained rice gruel. In addition, overflow of boiled water during preparation is quite unsuited for cooking in microwave ranges. SUMMARY OF THE INVENTION It is the basic object of the present invention to provide a gruel cooker for microwave range which enables preparation of savory rice gruel with no hard cores. It is another object of the present invention to prevent overflow of boiled water during preparation of rice gruel in microwave ranges. In accordance with the basic aspect of the present invention, a gruel cooker is made up of a microwave permeable bowl, a perforated microwave permeable rice container detachably encased in the bowl and a lid closing the open top end of the bowl. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of one embodiment of the gruel cooker in accordance with the present invention in a disassembled state. FIG. 2 is a side sectional view of the gruel cooker in the assembled state, and FIG. 3A to 3D are views for showing sequential steps in a process for preparing rice gruel using the gruel cooker of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS As briefly stated above, the gruel cooker of the present invention is made up of a bowl 1, a rice container 2 and a lid 3. The bowl 1 is made of a heatproof glass and provided with a bottom skirt 1a. The rice container 2 is made of microwave permeable, heatproof synthetic resin such as polyester resin. The rice container 2 is made up of an inverted bowl section 2a open at the bottom end and a lid supporter 2b projecting upwards from the top end of the bowl section 2a. More specifically, the bowl section 2a defines a space S for accommodating rice in cooperation with the inside bottom of the bowl 1 when the latter is assembled with the rice container 2 as shown in FIG. 2. For stable assembly with the bowl 1, the rice container 2 is provided with a bottom brim 2c. A number of slits 2d are formed side by side in the bowl section 2a near the bottom of the rice container 2 in order to allow free passage of water. These slits 2d are sized so as not to allow free passage of rice contained in the space S. In addition, presence of these slits 2d provides the bottom portion of the rice container 2 with flexibility large enough to allow snap engagement of the portion with the bottom skirt 1a of the bowl 1. Further, a number of small openings 2f are formed side by side in the bowl section 2a near its top end. These openings 2f are also sized so as not to allow free passage of rice contained in the space S. The lid supporter 2b is sized so as to project above the upper edge of the bowl 1 when the rice container 2 is assembled with the bowl 1 and provided, at its top end, with an upstanding positioning piece 2e for engagement with the lid 3. The lid 3 is made of microwave permeable heatproof synthetic resin such as polypropylene resin and somewhat larger than the top end opening of the bowl 1. The lid 3 is provided with a center recess 3a open downwards for receiving the positioning piece 2e on the rice container 2. A knob 3b is formed above the center recess 3a. The center recess 3a and the positioning piece 2e are sized and configurated so that a proper gap should be left between the lid 3 and the upper edge of the bowl 1 when the lid 3 is overlaid on the lid supporter 2b of the rice container 2 placed in the bowl 1. The size of the gap should be chosen so that no overflow of boiled water should occur during preparation of gruel in microwave ranges. Preferably, the gruel cooker further includes a bottom tray 4 made of heatproof, and more preferably microwave permeable, synthetic resin such as polypropylene resin. The tray 4 has a center recess 4a receptive of the bottom skirt 1a of the bowl 1 and four corners 4b suited for manual handling of the gruel cooker. In preparation of rice gruel, the rice container is turned upside down to receive uncooked rice in its bowl section 2a as shown in FIG. 3A. Next, the open end of the rice container 2 is force inserted into the skirt 1a of the bowl 1 for the snap engagement. As a consequence, the rice is confined within the space S defined by the bowl section 2a of the rice container 2 and the inside bottom of the bowl 1. The capacity of the space S should preferably be five to six times larger than the usual volume of uncooked rice used for one time of preparation. In other words, the proper volume of uncooked rice used for one time of preparation is one-sixth to one-fifth of the capacity of the space. Water is next supplied into the bowl 1 while shaking the latter in order to cleanse the uncooked rice. The old water is discharged and new water is supplied into the bowl 1 to a level just above the top end of the bowl section 2a of the rice container 2 as shown in FIG. 3B. The bowl 1 with the rice container 2 is placed in a position in a microwave range M as shown in FIG. 3C for boiling. During boiling water circulates into and out of the rice container 2 through the slits 2d and the openings 2f and, as a result of this boiled water circulation, the rice in the rice container 2 can be boiled quite uniformly without producing cores in particles. Since the lid 3 is kept at a position somewhat above the top end opening of the bowl 1, scattering and over flow of the boiled water are well prevented. After complete boiling, the bowl 1 is taken out of the microwave range M preferably with assistance of the bottom tray 4 and the rice container 2 is disassembled from the bowl 1. Next, the boiled rice in the rice container 2 is mixed with boiled water in the bowl 1 and the top end opening of the bowl 1 is closed by the lid 3 now disassembled from the rice container 2 for steaming of the rice gruel in the bowl 1. As a substitute of the uncooked rice, cooked rice can be used also for preparation of rice gruel with the gruel cooker in accordance with the present invention. The rice container 2 can be assembled with the bowl 1 in many known manners other than the snap engagement. In accordance with the present invention, active boiled water circulation through a space containing rice causes uniform boiling of the rice without producing cores in particles, thereby greatly improving relish of prepared rice gruel. No scattering and overflow of boiled water is in particular suited for cooking in microwave ranges.

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for installing a modularized semiconductor-processing device on a main frame and a method for maintaining the modularized semiconductor-processing device and peripherals. 2. Description of the Related Art In Japanese Patent Application No. 2001-196802, which is incorporated herein by reference, there is disclosed modularized semiconductor manufacturing equipment including a load-lock chamber, a transferring mechanism and a reaction chamber. FIG. 1 shows compact single-wafer-processing type semiconductor manufacturing equipment for forming a thin film on a semiconductor substrate, which is disclosed in the above-mentioned reference. FIG. 1 ( a ) is a plan view, FIG. 1 ( b ) is a front view, and FIG. 1 ( c ) is a side view of the equipment respectively. This equipment comprises a modularized reactor unit, an AFE portion [the portion which includes an atmosphere robot 5 for carrying in/out a substrate from within a cassette or a front opening unified pad (FOUP) 6 into/from a load-lock chamber] and a load boat in which the cassette or the FOUP 6 is positioned. The reactor unit is modularized by connecting two adjacent units. Each of the units comprises a reactor 1 for growing a film on a semiconductor substrate, a load-lock chamber 3 used for keeping the semiconductor substrate ready in vacuum, which is directly connected with the reactor 1 via a gate valve 2 , and a wafer handler 4 , which is positioned inside the load-lock chamber 3 . The wafer handler has one thin link-type arm for transferring a semiconductor substrate into the reactor 1 and moves the substrate in a straight-line direction. Modularizing the reactor units minimizes dead space inside the reactor unit and reduction in a faceprint 7 of the entire equipment. FIGS. 2 ( a ) to ( d ) illustrate the operation sequences of the semiconductor manufacturing equipment disclosed in the above-mentioned reference. In FIG. 2 ( a ), the atmosphere robot 5 carries a semiconductor substrate 20 from a cassette or a FOUP into respective load-lock chambers 3 via a flapper valve 21 . After this is completed, the flapper valve 21 is closed and air in the load-lock chamber 3 is evacuated. In FIG. 2 ( b ), the gate valve 2 is opened and the semiconductor substrate is transferred onto a susceptor 22 inside the reactor 1 by a wafer handler mechanism 4 . Because the wafer handler only reciprocates between the load-lock chamber and the reactor in a straight-line direction, only positioning is required, and no complicated teaching and adjustment are required. In FIG. 2 ( c ), wafer support pins 23 protrude from a susceptor surface and support the semiconductor substrate 20 . The arms of the wafer handler mechanism 4 are housed in the load-lock chamber and the gate valve is closed. In FIG. 2 ( d ), the susceptor 22 is raised and the semiconductor substrate 20 is placed on the surface of the susceptor 22 . Afterward, a thin film formation onto the semiconductor substrate 20 is started. After thin film formation is completed, the processed semiconductor substrate is transferred to a cassette or a FOUP in a reverse sequence of FIGS. 2 ( d )→( c )→( b )→( a ). In addition to a single-wafer-processing type, the modularized semiconductor-processing device is capable of handling multiple substrates simultaneously and of executing deposition processing simultaneously. Consequently, device throughput is high, and stable processes are provided. Generally, conventional load-lock type semiconductor manufacturing equipment comprised a load-lock chamber, a transfer chamber and a reaction chamber, and each chamber was directly attached to the main frame. Because of the construction, the only way of performing equipment maintenance was from the outside. Consequently, providing a space for maintenance work outside the equipment was required. Additionally, there was dead space in which no one was able to get in the center portion of the main frame, causing a problem that equipment footprint was increased when two units or more of the equipment were arranged transversely. When maintenance is performed, workers are compelled to do jobs within such narrow area and work becomes extremely difficult when a critical failure occurs. As a result, equipment downtime lengthens and throughput declines. The present invention was achieved in view of the above-mentioned problems. The object of the present invention is to provide semiconductor manufacturing equipment for which maintenance work can be performed easily and a maintenance method for the same. The second object of the present invention is to provide compact semiconductor manufacturing equipment for which there is no space for maintenance required and no dead space, hence the entire equipment footprint is small. The third object of the present invention is to provide semiconductor manufacturing equipment which reduces the time required for manufacturing devices and maintenance and improves throughput and a maintenance method for the same. SUMMARY OF THE INVENTION To achieve the above-mentioned objects, the semiconductor manufacturing equipment according to the present invention comprises a semiconductor-processing device in which a load-lock chamber, a transfer chamber and a reaction chamber are modularized into a main frame, a stand-alone chamber frame on which the semiconductor-processing device is placed, a sliding mechanism for enabling attaching/removing of the chamber frame to/from the main frame smoothly, and a positioning mechanism for fixing a position of the chamber frame, and which is characterized in that the modularized semiconductor-processing device is installed on the main frame in a manner that it can be attached and removed at will. Preferably, the sliding mechanism comprises a guide component attached to the sliding surface of the bottom of the main frame and bearings or resin plates, which are attached to the sliding surface of the bottom of the chamber frame. Preferably, the positioning mechanism comprises a bearing for positioning a y-axis direction, which is provided on the contact surface of the bottom of the main frame and wedge-shaped blocks for positioning x-axis and the z-axis directions. Multiple units of the semiconductor manufacturing equipment can be arranged transversely with no space between the units. The method for maintaining the semiconductor manufacturing equipment comprises the steps of pulling out the chamber frame, on which the modularized semiconductor-processing device is placed, from the main frame; forming a maintenance space inside the main frame; maintaining the semiconductor-processing device and peripherals attached in the vicinity of the main frame; and putting the chamber frame, on which the modularized semiconductor-processing device is placed, back into the main frame. BRIEF DESCRIPTION OF THE FIGURES FIG. 1 shows conventional modularized semiconductor manufacturing equipment. FIG. 2 shows an operation sequence of conventional modularized semiconductor manufacturing equipment. FIG. 3 shows a preferred embodiment and a maintenance sequence of the semiconductor manufacturing equipment according to the present invention. FIG. 4 shows another preferred embodiment and a maintenance sequence of the semiconductor manufacturing equipment according to the present invention. FIG. 5 is a plan view of two units of the semiconductor manufacturing equipment according to the present invention arranged and a maintenance method for this arrangement. FIG. 6 is a side view of two units of the semiconductor manufacturing equipment according to the present invention arranged and maintenance spaces for performing maintenance work. FIG. 7 is a plan view of multiple units of the semiconductor manufacturing equipment according to the present invention arranged and a maintenance method for this arrangement. DETAILED DESCRIPTION OF THE INVENTION Referring to FIG. 3 , the preferred semiconductor manufacturing equipment 30 according to the present invention comprises a main frame 31 , a modularized semiconductor-processing device 32 and a chamber frame 33 on which the semiconductor-processing device 32 is placed. A pair of spaced guides or rails 34 are attached respectively to the opposing bottom main frame members along an x-axis direction of the main frame 31 . Bearings or resin plates reducing friction resistance are installed on sliding surfaces 35 of the chamber frame, which slide along the guides 34 of the main frame 31 , enabling smooth sliding of the surfaces 35 or guides 34 . With this sliding mechanism, the modularized semiconductor-processing device 32 is installed in a manner that it can be attached and removed at will. Wedge-shaped blocks 36 are attached to bottom main frame members along a y-axis direction, in which the chamber frame 33 contacts inside the main frame 31 . Positioning of the x-axis direction and the y-axis direction of the chamber frame 33 is determined by the block 36 fitting in a concave portion 302 provided in the chamber frame 33 . A bearing 37 is attached to the center of the wedge-shaped block 36 of the main frame. Positioning of a y-axis direction of the chamber frame 33 is determined by the bearing 37 fitting in a concave portion 301 provided in the chamber frame 33 . Two spaced pressing blocks 38 are attached to bottom main frame members along the y-axis direction adjacent the ends of the guides 34 . The pressing blocks 38 function so that the bottom frame along a y-axis direction of the chamber frame 33 is pressed against the main frame 31 after the chamber frame 33 is completely installed inside the main frame 31 . By this function, positioning of an x-axis direction and a y-axis direction of the chamber frame 33 inside the main frame 31 is determined. With the positioning mechanism, re-teaching of an AFE robot for enabling the chamber frame once pulled out to be fixed at the identical position can be eliminated. FIGS. 3 ( a ) and ( e ) show that, when the modularized semiconductor-processing device 32 is installed, it is loaded inside the main frame 31 with no space between them. Thus, the modularized semiconductor-processing device 32 is integrated with the chamber frame 33 , and it can be moved freely and separately from the main frame 31 by attaching casters 39 at its bottom. This feature facilitates a worker to perform adjustment work of a reactor and a load-lock chamber by pulling out the modularized semiconductor-processing device from the main frame 31 . At the time of a serious failure, an entire assembly can be replaced by replacing a module. FIG. 4 shows another embodiment of the semiconductor manufacturing equipment according to the present invention. The semiconductor manufacturing equipment 40 comprises a main frame 41 , a modularized semiconductor-processing device 32 and a chamber frame 43 on which the semiconductor-processing device 32 is placed. A V-shaped groove 47 is provided along an x-axis direction on the bottom of the main frame 41 . A flat groove 48 is provided on the bottom of the main frame 41 opposing the V-shaped groove 47 along an x-axis direction. The V-shaped groove 47 and the flat groove 48 function as a positioning mechanism in the y-axis direction of the chamber frame 43 as well. Bearings or resin plates are attached to the V-shaped groove 47 and the flat groove 48 for reducing friction resistance, enabling smooth sliding of the V-shaped groove 47 and the flat groove 48 along the sliding surfaces 408 of the chamber plate. With this sliding mechanism, the modularized semiconductor-processing device 32 is installed on the main frame 41 in a manner that it can be attached and removed at will. Shock absorbers 44 are attached to side surfaces of the V-shaped groove 47 and the flat groove 48 of the main frame 41 so that the main frame 41 does not experience a shock caused by inertia when the chamber frame 43 is installed. Casters 42 are attached at the rear end of the bottom of the chamber frame 43 . The casters 42 provide a support when the chamber frame 43 is pulled out and function as a positioning plate in the x-axis direction when the chamber frame 43 is installed. A leveling adjuster 49 is attached so that leveling in a z-axis direction can be done by the chamber frame alone when a chamber is assembled, etc. One sliding surface 46 of the chamber frame 43 protrudes in a V-shape to accommodate the V-shaped groove 47 of the main frame 41 . With the sliding surface 46 protruding in the V-shape sliding with the V-shaped groove 47 , positioning of a y-axis direction of the chamber frame 43 is determined. With the positioning mechanism, re-teaching of an AFE robot for enabling the chamber frame once pulled out to be fixed at the identical position can be eliminated. FIG. 4 ( a ) demonstrates that the modularized semiconductor-processing device 32 is loaded with no space between inside the main frame 41 at the time of installation. The modularized semiconductor-processing device 32 is integrated with the chamber frame 43 . By attaching casters 42 at its bottom, the device can be moved freely and separately from the main frame 41 (FIG. 4 ( c )). This feature facilitates the worker to perform adjustment work of a reactor and a load-lock chamber by pulling out the modularized semiconductor-processing device from the main frame 41 . At the time of a serious failure, an entire assembly can be replaced by replacing a module. Returning to FIG. 3 , a maintenance method of the semiconductor manufacturing equipment according to the present invention is described. First, preparatory for pulling out the chamber frame 33 from the main frame 31 , the pressing blocks 38 are released (FIG. 3 ( a )). While the chamber frame 33 is pulled out gradually, casters 39 are attached to the rear end of the bottom of the chamber frame (FIG. 3 ( b )). By pulling out the chamber frame 33 further, casters 39 are attached to the front end of its bottom (FIG. 3 ( c )). With the chamber frame pulled out completely, maintenance of the load-lock chamber, the reactor and peripherals of the main frame is performed (FIG. 3 ( d )). Lastly, the chamber frame is installed by positioning it inside the main frame 31 , and is fixed with the pressing blocks (FIG. 3 ( e )). FIG. 5 and FIG. 6 illustrate a maintenance method when two units of the semiconductor manufacturing equipment according to the present invention are arranged transversely. FIG. 5 shows a plan view of the entire semiconductor manufacturing equipment. FIG. 6 shows its side view. The entire semiconductor manufacturing equipment comprises a load boat portion in which cassettes or FOUP's 50 are positioned, an AFE portion including atmosphere robots 51 , and a modularized reactor unit portion 52 . FIG. 5 and FIG. 6 show a position in which one of the reactor units 53 of the semiconductor manufacturing equipment according to the present invention is pulled out halfway. By pulling out the reactor unit 53 in an arrow 55 direction, a maintenance space 56 is formed inside the main frame. By entering the maintenance space 56 , a worker 54 can perform maintenance work. For example, the worker 54 can perform maintenance work of the load-lock side 62 of the reactor unit 53 pulled out as indicated by a. Or, the worker 54 can perform maintenance work of the AFE side 60 , which is an opposite side of the load-lock side. The worker 54 can perform maintenance work of electrical components, etc. installed on a ceiling portion 61 of the main frame as indicated by b. From outside the main frame, the worker can perform maintenance work of the reactor portion of the reactor unit 53 pulled out as indicated by c. After maintenance work is completed, by putting the reactor unit 53 back to its original position inside the main frame, the maintenance space 56 disappears. Thus, using the semiconductor manufacturing equipment according to the present invention, a maintenance space can be formed only when maintenance work is performed, hence the footprint of the entire equipment can be minimized. Additionally, because maintenance can be performed exceedingly easily and effectively, work hours are shortened and throughput of the semiconductor manufacturing equipment improves. FIG. 7 shows a plan view of the entire equipment and a maintenance method when five units of the semiconductor manufacturing equipment ( 71 , 72 , 73 , 74 , and 75 ) according to the present invention are arranged transversely with no space between the units. In this case, reactor units 72 and 74 for which maintenance work is performed are pulled out completely. As shown in FIG. 7 , when multiple reactor units are arranged with no space between, maintenance work of two units at both ends ( 71 , 75 ) can be performed by pulling them out halfway as shown in FIG. 5 . Maintenance work of other three reactor units ( 72 , 73 , and 74 ) can be performed by pulling them out completely. By pulling out reactor units 72 and 74 , maintenance spaces 76 and 77 are respectively formed. The worker 54 can perform maintenance work of the load-lock side of the reactor units pulled out as indicated by a. The worker 54 can perform maintenance work of the chamber of the adjoining reactor unit from a side as indicated by b. The worker 54 can perform maintenance work of electrical components attached midway in the main frame as indicated by c. The worker 54 can perform maintenance work of the atmosphere robot on the AFE side and other devices as indicated by d. After maintenance work is completed, by putting the reactor units 72 and 74 back to their original positions inside the main frame, the maintenance spaces 76 and 77 disappear. Thus, the semiconductor manufacturing equipment according to the present invention enables arranging of multiple units of semiconductor manufacturing equipment transversely and the footprint of the entire equipment can be minimized. Additionally, because a maintenance space can be formed inside the main frame by selectively pulling out chamber frames for which maintenance work is required, maintenance work can be performed exceedingly easily and effectively. Consequently, work hours required for maintenance are shortened and throughput of the equipment improves. Using the semiconductor manufacturing equipment and the maintenance method according to the present invention, maintenance can be performed exceedingly easily and effectively. Additionally, the semiconductor manufacturing equipment according to the present invention does not have a space for maintenance use and dead space. The footprint of the entire equipment is small and compact. EXPLANATION OF SYMBOLS USED 30 Semiconductor manufacturing equipment 31 Main frame 32 Modularized semiconductor processing device 33 Chamber frame 34 Guide component 35 Sliding surface 36 Wedge-shaped block 37 Bearing 38 Pressing block 39 Caster 40 Concave portion 41 Concave portion

4y

BACKGROUND OF INVENTION 1. Field of the Invention The present invention relates generally to a highly scalable directory, and in particular to such a directory using multiple integrated delegate directory service agents. 2. Description of Related Art Various directory systems have been used conventionally to organize electronically stored information, especially to facilitate subsequent retrieval by a user. The X.500 directory model has been implemented in various directory systems. X.500 model-based directory systems are typically used to support querying by human users. Such systems allow users to find information such as telephone numbers, addresses and other details of individuals and organizations in a convenient structure. X.500 directories are characterized by their ability to efficiently handle large, highly distributed information. For example, a number of server based directory service agents (DSAs) may be connected to form a global X.500 directory. The individual directory service agents are maintained by different organizations throughout the world and are interconnected via a series of communication links. An X.500 directory is often times distributed on an organizational basis. The directory is organized in a hierarchial structure having entries arranged in the shape of a tree, commonly referred to as a directory information tree (DIT). An exemplary directory information tree is illustrated in FIG. 13. In the illustrated example, entries for countries 11 and 12, and organizations of national significance 21, 22, and 23, appear towards the root 10 of the tree. Entries for individuals 41, 42, and 43 and small organizations 31, 32, and 33 appear towards the leaves the tree. An entry which does not have any further entries depending therefrom is commonly referred to as a leaf entry. Every entry in the directory information tree has a distinguished name that unambiguously identifies the particular entry. The distinguished name of a particular entry is derived from the structure of the directory information tree by combining the relative distinguished names from all entries higher up the tree. For example, entry 41 of the directory information tree illustrated in FIG. 13, has a distinguished name of the form: cn=Timothy A. House, ou=Faculty and Staff, o=University of Michigan, c=U.S. Information in the directory information tree is typically accessed using a directory user agent (DUA) connected to the directory service. The directory user agent assists a user in formulating queries, provides the required protocol for the queries and passes them to the directory to retrieve the information. The retrieved information is typically displayed to the user by the directory user agent. In a conventional X.500 directory system, the OSI standards (Standard Reference Model for Open Systems Interconnection) do not define the directory user agent, but rather establish protocols that should be used by a directory user agent when communicating with such a directory. Typically, a directory user agent communicates with the directory using a directory access protocol (DAP) or another protocol fulfilling the same function such as the light directory access protocol (LDAP). Accesses to the information within the directory information tree via a request from a directory user agent are typically handled by the directory service agent managing the directory information tree. The directory service agent may directly handle the request itself or may alteratively inquire of another directory service agent using the directory system protocol. The process of directing an inquiry to another directory service agent is generally referred to as chaining (i.e., the request is chained to another directory service agent). One convenient form of a directory service agent is the QUIPU directory service agent which provides an environment for modifying the standardized directory services. A detailed description of an X.500 OSI directory service and QUIPU directory service agent technology is provided in ISODE Volume 5: Administrator's Guide: Directory Services (May 1994 ed.). While the strength of a QUIPU directory service agent includes its high distributivity, it encounters difficulties in handling large centralized directories. Thus, in order to migrate a large, centralized directory to a QUIPU-based X.500 directory, the legacy directory information needs to be split and disseminated to multiple directory service agent servers. Such an approach is expensive, both in terms of hardware and administrative resources. Moreover, such an approach does not solve the need to administer and store large amounts of non-distributed information. A conventional QUIPU directory service agent readily supports directories having 40,000 entries using a single local directory service agent. In this approach, all directory information is loaded into the main memory of the directory service agent server when the directory service agent is started. This approach produces catastrophic memory errors when the number of entries in the directory exceeds 50,000. Thus, a conventional QUIPU directory service agent cannot be used for large centralized (non-distributed) directories. In order to increase the capacity of QUIPU technology, a specialized delegate directory service agent may be implemented in connection with a QUIPU directory service agent. In this approach, a disk-based (rather than main memory-based) single delegate directory service agent process is installed on the server which implements the memory-based directory service agent. The memory-based directory service agent is constructed as a specialized adjacent directory service agent to which requests may be chained as needed. In this approach, when a request is chained to the delegate directory service agent, the delegate directory service agent accesses indexed files, which are created during a preprocessing stage, to serve the chained request. This use of a delegate directory service agent is described more fully in the above-referenced ISODE publication. With the above approach, the use of a delegate directory service agent provides a successful implementation of a QUIPU implemented X.500 directory having approximately 100,000 entries. However, this approach also fails to perform adequately as the number of entries in the directory is increased to approximately 150,000. Thus, while the delegate directory service agent technology has doubled the capacity of the original QUIPU architecture, it still has a limited capacity (i.e., does not have a scalability sufficient to meet the needs of numerous enterprises having a need for larger localized directories). Thus, a large corporation having 300,000 employees could not use a single server to implement a centralized directory. Thus, in such systems, the directory information still must be split and disseminated onto multiple servers increasing the cost of implementing the directory and limiting the ability to have a large, non-distributed directory. SUMMARY OF THE INVENTION To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a method and apparatus for providing an improved directory service which is highly scalable and which is able to handle large non-distributed directories. The present invention may be implemented in the form of a directory service system for accessing information stored in an X.500 directory information tree. The system includes a first directory service agent coupled to receive a query from a directory user agent. The first directory service agent manages information in the root of the directory information tree. The system also includes multiple delegate directory service agents coupled to the first directory service agent. The delegate directory service agents each manage corresponding portions of the directory information tree beneath the root. In response to the query from the directory user agent, a request is chained to each of the delegate directory service agents. The response to the chained request from each of the delegate directory service agents is provided to the first directory service agent. In one embodiment, each of the delegate directory service agents are implemented in parallel on corresponding parallel processors incorporated in a single server. An object of the present invention is to provide a highly scalable directory service. Another object of the present invention is to provide a directory service which is able to handle large non-distributed directories. Still another object of the present invention is to provide an improved directory service using multiple delegate directory service agents. Another object of the invention is to provide a directory service where multiple delegate directory service agents are implemented on separate processors operating in parallel. Yet another object of the present invention is to provide a user interface which facilitates setup and management of the improved directory service. BRIEF DESCRIPTION OF THE DRAWINGS The invention may be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which: FIG. 1 illustrates a directory system in accordance with an embodiment of the invention; FIG. 2 illustrates a directory information tree in accordance with an embodiment of the present invention; FIG. 3 illustrates a graphical user interface window in accordance with an embodiment of the present invention; FIG. 4 illustrates another graphical user interface window in accordance with an embodiment of the present invention; FIG. 5 illustrates still another graphical user interface window in accordance with an embodiment of the present invention; FIG. 6 illustrates a further graphical user interface window in accordance with an embodiment of the present invention; FIG. 7 illustrates another graphical user interface window in accordance with an embodiment of the present invention; FIG. 8 also illustrates a graphical user interface window in accordance with an embodiment of the present invention; FIG. 9 illustrates another graphical user interface window in accordance with an embodiment of the present invention; FIG. 10 illustrates still another graphical user interface window in accordance with an embodiment of the present invention; FIG. 11 illustrates another graphical user interface window in accordance with an embodiment of the present invention; FIG. 12 illustrates a further graphical user interface window in accordance with an embodiment of the present invention; FIG. 13 illustrates a conventional directory information tree. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In the following description of various embodiments, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. FIG. 1 illustrates an exemplary embodiment of a directory service system. In accordance with this embodiment, a high degree of scalability is provided for a directory system. The system illustrated may be used to support a large, centralized X.500 directory. As illustrated in FIG. 1, management of information organized in an X.500 directory information tree is divided between a QUIPU directory service agent 100 and multiple delegate directory service agents 101, 102, 103, and 104, all of which are implemented in a server 107. The QUIPU directory service agent 100 loads all of the information which it handles into the main memory of the server 107 when the directory service process is started. Information to be handled by the delegate directory service agents 101-104 may be stored, for example, in UNIX db formatted index files in a disk memory. The delegate directory service agents 101-104 read information from the UNIX db formatted index files as needed to service directory requests. The QUIPU delegate service agent process 100 is defined in the illustrated example as a level one directory service agent. As such, the QUIPU directory service agent 100 is responsible for storing and managing information at the top (near the root) of the X.500 directory information tree. The lower branches of the directory information tree are maintained by the various delegate directory service agents 101-104. The QUIPU directory service agent 100 receives all directory requests initiated by a directory user agent and automatically chains the requests to each of the delegate directory service agents 101-104. FIG. 1 also illustrates various directory user agents which may be used to request information from the directory service implemented on server 107. The directory user agents include a directory interface shell (DISH) application 106, a light directory access protocol (LDAP) daemon process 105 and a remote directory service agent server 110. The DISH interface 106 provides server-based access to the directory and provides a powerful interface onto the directory to give a user access to the full directory access protocol. Such an interface is typically used to provide system administrators access to the system. The LDAP daemon process 105 may be used to service directory requests originating from directory user agent (DUA) applications such as DUA application 108. Such a directory user agent application 108 typically resides in a client 109 connected to the directory via a local area network (LAN). The directory may also be accessed by a remotely located conventional directory service agent server 110. Communication with the conventional remote directory service agent server 110 is implemented using standard directory access protocols for communication between conventionally distributed directory service agent servers. In operation, when a query is received by the QUIPU directory service agent 100, the request is chained to each delegate directory service agent 101-104 asynchronously. As the responses from the various delegate directory service agents 101-104 are received by the QUIPU directory service agent 100, they are combined to form a complete response to the user's query. The concatenated result is sent to the requester (i.e., to the DISH process 106 for display on the local server 107, to the LDAP daemon process 105 which provides the results to the DUA application 108, or to the remote directory service agent 110). It is noted that there are no fixed limits to the number of delegate directory service agents 100-104 which can be implemented using the configuration of FIG. 1. The practical limit is the amount of information which can be handled by the host processor of server 107. In order to provide improved performance and nearly unlimited scalability, the server 107 may be implemented using a hardware platform incorporating multiple parallel processors. For ideal performance, each processor in the server 107 supports a process of one of the delegate directory service agents 101-104. For example, the S/3000 AT&T Server System, which is a multi-processing platform, can be used as the server 107. Such a system could support a very large number of delegate directory service agent processes and provide nearly unlimited directory scalability. In the above example, multiple delegate directory service agents are provided in order to increase the number of entries which can be handled by a single server-based directory. The principles described can also be used to improve performance of a directory service of any size. For example, the performance of a relatively small directory may be improved by implementing the directory using multiple delegate directory service agents to handle relatively small portions of the directory. Each directory service agent process would be respectively executed on one of the multiple parallel processors. FIG. 2 illustrates an exemplary directory information tree which supports the use of multiple delegate directory service agent processes. As depicted in FIG. 2, the root 200 of the directory and the information contained in this portion of the directory information tree are managed by the QUIPU directory service agent process 201. The directory is automatically configured with the distinguished name "c=<country name>, o=<organization name>" where <country name> and <organization name> are provided by the administrator. Below the root 200, organizational unit non-leaf entries 202, 203, and 204 are automatically created for each delegate directory service agent specified by the administrator. These non-leaf entries 202, 203, and 204 define the delegate directory service agent processes and are managed by the QUIPU directory service agent 201. Below the organizational unit nodes 202, 203, and 204, the administrator may create directory information tree branches 205, 206, and 207 that are managed by the specific delegate directory service agent processes 208, 209, and 210, respectively. In this manner, an administrator may efficiently divide a large localized directory into the multiple delegate directory service agent processes in order to efficiently handle the entries on a single server. The illustrated system, may be administrated and implemented using standard open directory systems technologies with modifications to allow the administrator to set up and manage the multiple delegate directory service agents. For example, the AT&T open directory system, as described in "Open Directory Administrator Guide" D1-4765-A (July 1995), may be modified to provide administrative management utilities designed to facilitate the use of multiple delegate directory service agents. FIGS. 3-12 depict an exemplary interface which may be incorporated into a system such as the AT&T open directory system to assist management of a directory implemented using multiple delegate directory service agents. The example also identifies the general types of tasks which would be carried out to set up a directory using multiple delegate directory service agents. The graphical user interface allows a directory administrator to define the multi-processing configuration in an intuitive manner without an understanding of the underlying configuration requirements of the QUIPU technologies used. A first menu, as illustrated in FIG. 3, is displayed when the administration utility is invoked. The "Install" 300 and "GDA" 301 choices allow the administrator to add an organizational unit non-leaf entry to the directory information tree to define a delegate directory service agent. The "Deinstall" 302 choice removes the specified delegate directory service agent process and the associated branch of the directory information tree from the directory. When the "Install" 300 and the "GDA" 301 choices are made to add a delegate directory service agent process to the configuration, the dialog box illustrated in FIG. 4 is presented. The "GDA Alias" 400, the distinguished name "DN" of the delegate subtree 404, and "Password" 401 can be entered directly into the input fields within this box. The "Indexed Attributes" button 402 and the "Bind Information" tree 403 can be used to display additional dialog boxes for specifying other configuration information. It is noted that an alias entry, such as the GDA alias 400, is an entry in the directory information tree which has its own distinguished name, but only points to another entry and does not hold full information for the entry. Depressing the "Indexed Attributes" button 402, displays the dialog box shown in FIG. 5. New directory attributes can be added to the list of the index attributes, by typing the attribute name in the "Add Item" field 501 and depressing the "Add" button 502. As attributes are added to the list, they are displayed in the "Indexed Attributes" window 500. Attributes can be deleted from the index list by selecting the attribute name from the "Indexed Attributes" window 500 and depressing the "Delete" button 503. Additional configuration options are available through the "Operations" option of the main administrative menu as shown in FIG. 6. Depressing the operations menu option 600 results in a drop down menu with additional choices. The "Tailor" option 601 allows the administrator to choose configuration options for the QUIPU directory service agent 602 or a delegate directory service agent process 603. Specifying the GDA option 603 causes a separate menu to be displayed as shown in FIG. 7. Menu screen 700 allows the administrator to choose which delegate directory service agent configuration to tailor. The alias names of all installed delegate directory service agent processes are listed in the GDA's window 701. To choose a specified delegate directory service agent, the administrator highlights the appropriate alias name with the GDA window 701 and depresses the "OK" button 702. The delegate directory service agent configuration tailor dialog box is shown in FIG. 8. The delegate directory service agent alias name 809 is displayed on the top of the screen. The distinguished name of the non-leaf node representing the delegate directory service agent 800 is also shown. Configurable size limitations can be set by entering values into three input fields 801, 802, and 803 within the dialog box. Additional configuration parameters can be set by depressing the "Directory Service Agent Address" button 804, the "Manager" button 805, and the "Logs" button 806. To save all the entered information the "OK" button 807 is depressed. The dialog box shown in FIG. 9, is displayed as a result of choosing the "Directory Service Agent Address" button 804. A T-selector can be specified in the first field 900. A hexadecimal value can be entered by depressing the "HEX" button 901. For TCP/IP (Transmission Control Protocol/Internet Protocol) configurations the name or address and a part number can be added in the input fields 902 and 903 on the second line of the dialog box. An OSI address is entered into the "NSAP" input field 904. Fields 905 and 906 are also provided to configured for X.25 addressing (i.e., the CCITT recommendation entitled "Interface between Data Terminal Equipment and Data Circuit Terminating Equipment for Terminals Operating in the Packet Mode and Connected to Public Data Networks by Dedicated Circuit"). APS (Asynchronous Protocol Specification) configuration information, specified in the "Name" 907 and the "Phone Number" 908 fields, are not applicable to delegate directory service agent configuration. Information is saved by depressing the "OK" button 909. Selecting the "Manager" button 805 from the "GDA Tailor" dialog box 808, results in the screen depicted in FIG. 10. The dialog box is used to specify which managers are granted special privileges to access the delegate directory information subtree. Manager names are entered in the "Add Item" input field 1002. The "Add" button 1003 is used to save the new item. Existing items are displayed in the "GDA Manager" window 1001. An item can be deleted by highlighting it in the "GDA Manager" window 1001 and depressing the "Delete" button 1004. Selecting the "Logs" button 806 from the GDA tailor dialog box 808 causes the dialog box shown in FIG. 11 to be displayed. Controls are provided for the two separate logs maintained by the delegate directory service agent. The delegate directory service agent protocol trace options are displayed on the left hand of this screen 1101, while the statistic log options are displayed on the right 1102. The type of logging can be toggled by depressing the appropriate "Exceptions" buttons 1103 and 1105, "Notice" buttons 1104 and 1106, or "Fatal" buttons 1110, 1111. The maximum size of the log files can be specified in the "Log Size" fields 1107 and 1108. Log settings can be set to default values using the "Reset" button 1112. To save the log settings, the "OK" button 1109 is depressed. The interface further facilitates administration by providing user interfaces to manage the method and system. Interfaces to start, stop and query process status are displayed by specifying the "Process Control" option 605 of the main directory administration menu 604 illustrated in FIG. 6. The "Process Control" dialog box 1200 is depicted in FIG. 12. The various directory service agent processes configured are displayed in the "Process/Status"window 1201. The administrator can specify if this screen 1200 should be automatically updated by toggling the "Auto-Update" button 1202. The duration between updates is specified in the corresponding input field 1203. An additional "LDAP Status" toggle button 1204 is used to specify whether status of the LDAP daemon (element 105, FIG. 5) should be displayed in the "Process/Status" window 1201. The administrator specifies whether the QUIPU directory service agent and delegate directory service agent processes should be started when the operating system is rebooted by toggling the "Auto Start" button 1205. A particular process may be started or stopped by depressing the "Start" button 1206 and the "Stop" button 1207, respectively. The foregoing description of various embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teaching. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.

4y

This invention relates to the treatment of polymeric surfaces and, more particularly, to a gas plasma process for changing the characteristics of a thermoplastic polymeric surface (e.g., to provide wettability, to enhance paint adhesion) without subjecting the surface to chemical, flame, or electrical oxidation and, optionally, without depositing films of other materials on the polymeric surface. BACKGROUND OF THE INVENTION There are many known methods for treating polymer surfaces to alter their properties, including those that involve flaming, corona discharge, chemical oxidation, electrode discharge processes, or plasma treatment in the presence of specific gases and chemical species, or various combinations of these processes. All of these known processes have certain limitations, including difficulty in maintaining quality control at desirable production speeds, deleterious effects on the polymer substrate, or ineffective or inadequate results with particular polymeric substrates. Chemical oxidations, for instance, are generally wet processes and, therefore, are relatively slow and have all the attendant problems connected with coating, cleaning and drying materials so treated. Flame treatments are also slow and often adversely affect the bulk properties of the material being treated, particularly if not very carefully controlled, and of course, they also present a constant fire hazard. Corona discharge treatments involving potential gradients across the material being treated often cause pinholes in the material and induced electrostatic charges which raise many problems for post-treatment handling. Electrode discharge systems are hard to maintain because, in the presence of organic materials, one of the typical effects of such discharges is the formation of polymeric films on the electrodes. Such discharge systems, therefore, require constant cleaning of electrodes to remove the polymeric film which acts as an insulator, thereby slowing the flow of the current. A simple and effective gas plasma treatment to improve paint adhesion is not readily available, especially for articles based on or coated with polyolefins, polycarbonate or polyvinyl chloride (PVC). U.S. Pat. No. 4,072,769 (D. D. Lidel) refers to a previously known method in which polymeric surfaces are bathed in an atmosphere of nitrous oxide (N 2 O) at elevated temperatures and in the presence of ultraviolet radiation. The result of this process is said to be similar to the flame, chemical and corona discharge processes referred to above, namely, the ultraviolet radiation breaks up other bonds as well as carbon-hydrogen bonds (even carbon-carbon bonds) causing relatively severe degradation of the surface of the polymer. U.S. Pat. Nos. 4,072,769 and 3,761,299 disclose a process for modifying the surface characteristics of polymeric materials by exposure of the materials to a reactive gas which has been activated by radio frequency electromagnetic radiation prior to the gas being directed to the polymer surface. The references teach that the invention is based on the discovery that when certain specific activator gases, i.e., the noble gases and nitrogen, when activated by radio frequency electromagnetic radiation, produce free radical sites when brought into contact with polymer surfaces and also produce free radicals from the organic or inorganic vapors (e.g., water) introduced into the activator gas stream (the organic or inorganic vapors are referred to as reactive gases). When a gas stream combining both the activator gas and reactive gas are discharged onto a polymer surface, a reaction is reported to occur between the free radicals generated at the polymer surface by the activator gas and in the reactive gas by the activator gas to provide the desired result. Certain reactive gases are said to provide satisfactory results even in the absence of an activator gas. Excellent results are said to be obtained by using certain inorganic gases alone, namely, nitrogen trioxide (N 2 O 3 ) and the "odd molecules" nitrogen oxide (NO) and nitrogen dioxide (NO 2 ). The reference suggests that similar results should be obtained using a reactive gas consisting of any other odd molecules (e.g., ClO 2 , O 2 , OF, etc.) which exist naturally with 3-electron bonds. In addition, water vapor alone produces satisfactory results. Alternatively, vapors of "many" organic compounds are said to be useful as the reactive gas, but only in combination with at least one of the activator gases prior to activation by the electromagnetic field. The Lidel reference also refers to a prior art treatment for increasing the hydrophilicity of materials as disclosed by J. S. Hayward in U.S. Pat. No. 3,526,583. Lidel states that, according to the Hayward process, normally hydrophobic polymer surfaces can be rendered hydrophilic when bathed, in the presence of air, in a stream of an activated species of one of the noble gases, or of hydrogen, nitrogen, or oxygen (the latter gas being by far the least effective). It is said that the Hayward process indicates that activated gas species will attack polymer surfaces in a relatively gentle manner to cause some changes in the surface molecules. Surface modification of polyethylene is utilized by another prior art process known as Casing-Crosslinking by Activated Species of Inert Gases (Chem. and Eng. News. Vol. 44, Sep. 26, 1966, pgs. 58 and 59, by Hanson et al.) which applies electronically excited species of inert gases (helium, argon, krypton, neon and xenon) to the surface to increase the cohesive strength of the surface molecules. The reference discussing the Casing process suggests that such activated gases do not necessarily change the wettability of the polymer surface for water, but that the activated gas attacks the surface of a polymer in a relatively gentle manner to form free radical sites. However, the reference states that Casing does not strengthen adhesive joints made with polypropylene and the evidence shows that both crosslinked and degraded polymer is formed at the surface, resulting in little change in cohesive strength of the surface region. U.S. Pat. No. 4,276,138 to M. Asai et al. (the '138 patent) discloses a method for reducing static electricity on the surface of a shaped article made of PVC resins which comprises blending a surface active agent with the PVC resin prior to fabrication of the article and subjecting the article to treatment with a low temperature plasma gas. The incorporation of a surface active agent is critical to the invention. The gases include helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen, halogens, halogen compounds, olefins, halogenated hydrocarbons, aromatic hydrocarbons and heterocyclic organic compounds organosilanes. Inorganic gases are preferred, especially helium, argon, carbon monoxide, carbon dioxide, and hydrogen because of higher efficiency due to an unknown mechanism. When mixtures of gases are used (optionally), it is recommended that one of the components is carbon monoxide (CO). U.S. Pat. No. 4,247,440 to M. Asai et al. discloses a method for preventing plasticizer bleeding on PVC shaped articles. The method requires the use of at least 20 parts of plasticizer per 100 parts of PVC which plasticizer must include at least 10% of a compound having at least one aromatic nucleus in a molecule (mixtures of plasticizers can be used). The low temperature plasma gases which are useful in the process include the same list of gases as in the '138 patent with the same preferences for inorganic gases and carbon monoxide. U.S. Pat. No. 4,272,464 to M. Asai et al. also deals with a method for preventing plasticizer bleeding, but it requires the blending of a urethane elastomer with the PVC resin prior to fabrication and plasma treatment. Again the same gases and preferred gases are disclosed as in the '138 patent. Improved surface properties are said to be obtained with PVC articles according to U.S. Pat. No. 4,247,577 to K. Imada et al. when a covering layer of a curable organopolysiloxane composition is placed on the surface of the article after it is treated with a low temperature plasma gas. Suitable gases are helium, neon, argon, nitrogen, oxygen, air, nitrous oxide, nitrogen dioxide, carbon monoxide, carbon dioxide and hydrogen sulfide. U.S. Pat. No. 4,302,307, also to K. Imada et al., discloses a treatment of PVC gramophone records in a low temperature plasma gas to improve antistatic properties. The gases are selected from inorganic or inert gases such as helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, chlorine, hydrogen chloride,, carbon dioxide and hydrogen. It is reported that the gases can be used singly or in mixtures, but that argon or argon-containing mixed gas is preferred because of higher efficiency. U.S. Pat. No. 4,315,808 to K. Imada et al. discloses a method for modifying the surface properties of shaped PVC articles with a low temperature plasma to prevent bleeding of plasticizer or other additive ingredients in the shaped article. The method requires intermittent exposure to the gas plasma (at least five exposure and repose times of specified duration) rather than continuous exposure. The list of useful gases is extensive, but limited to inorganic gases including helium, neon, argon, nitrogen, nitrous oxide, nitrogen dioxide, oxygen, air, carbon monoxide, carbon dioxide, hydrogen, chlorine, halogen compounds, such as hydrogen chloride, bromine cyanide and sulfur compounds, such as sulfur dioxide, and hydrogen sulfide. It is also suggested that gases may be used singly or in mixtures, but that the oxygen-containing compounds are less preferred, e.g., oxygen, air and nitrogen oxides, as well as halogen compounds and sulfur compounds. U.S. Pat. No. 4,396,641 to K. Imada et al. discloses a method for improving the surface properties of shaped articles of synthetic resins which is said to be applicable to not only PVC, but to other kinds of synthetic resins including thermoplastic and thermosetting resins such as low- and high-density polyethylenes, polypropylenes, polystyrenes, etc. However the gaseous composition of the plasma atmosphere requires the presence of a specific organic silicon compound. Improved results are said to be obtained when the organic silicon compounded is diluted with an inert inorganic gas selected from nitrogen, nitrogen oxides and helium, argon, neon and xenon. Furthermore it is necessary that the plasma treated article be contacted with a halogen or a halogen containing inorganic or organic compound. U.S. Pat. No. 4,337,768 teaches that it is well known that crosslinked thin layers on the surfaces of chlorine-containing vinyl polymers, such as PVC and polyvinylidene chloride, formed by glow discharge or UV radiation, act as barriers to migration of lower molecular weight substances such as monomers, plasticizers and additives to the surface. However the method disclosed in this reference includes a gas mixture for use in the "glow discharge" consisting of carbon monoxide (CO) and at least one different gas selected from the group consisting of argon, nitrogen, carbon dioxide, water, etc. A gas mixture of CO and CF 4 is characteristic. The use of a mixture of CO and H 2 O is especially preferred for producing film useful in blood bags. The modified surface layer is described as having a specified thickness, being crosslinked and having reduced chlorine content (45% or less) compared to the uncrosslinked portion. Treatment of a fluorocarbon polymer with a gas plasma to improve surface adhesive properties (i.e., heat sealing) is disclosed in U.S. Pat. No. 4,735,996. However, two critical process elements are noted: (1) the power density of the plasma is preferably 0.03 to 10 W.sec/cm 2 in order to control the concentration of fluorine atoms on the surface of the polymer to within particular limits, and (2) the gas composition which is selected from Ar, H 2 , CO, CO 2 , NH 3 , SO 2 , HCl, freon gases such as CF 4 , H 2 S and mixtures with other unspecified gases. However, the oxygen content of the gas has to be less than 10 mol %, or have a CO content of more than 10 mole %, or with an NH 3 content of more than 0.1 mole %. U.S. Pat. No. 4,828,871 discloses that shaped polymer articles, for example, polypropylene films, can be made more receptive to organic coatings (such as pressure sensitive adhesives) by exposure of the article to an electrical discharge in the presence of a chlorocarbon or chlorofluorocarbon gas, thereby generating a chlorine-containing surface layer. U.S. Pat. No. 5,152,879 discloses a process for the low pressure plasma treatment of polyolefin films using oxygen-containing gases, such as O 2 , H 2 O 2 , H 2 O, N 2 O, NO 2 or O 3 and mixtures with noble gases such as He, Ne, Ar, Kr or Xe. The process is said to be particularly useful for preparing multilayer films. Important process parameters for improved bonding or adhesion of the film are reported to be (1) maintaining the energy density on a unit surface of polyolefin film at or above 0.01 or above 10 Ws/cm 2 , (2) keeping the polyolefin film at a distance of at least 60 mm from the electrodes to which the electric field for the production of the plasma is applied and (3) maintaining the temperature of the film at or below 30° C. during the treatment, preferably from -2° C. to 10° C. Plasma treatment of highly oriented polyolefins having an ultrahigh molecular weight to produce articles having good wetting and adhesion properties without reducing their tensile strength is carried out with inert and/or reactive gases or gas mixtures, the use of reactive gases being preferred. Suitable inert gases are nitrogen and helium, and suitable reactive gases include air, oxygen, carbon dioxide and ammonia. Preferably chemical treatment of the polyolefin is carried out immediately after plasma treatment to improve the wetting and adhesive properties of the plasma treated articles. Chemical treatment is proposed using various broad classes of reagents, including those with carboxyl groups, hydroxyl groups or carbonyl groups. In an effort to improve the paintability of polyvinyl halide compositions, U.S. Pat. No. 5,198,303 teaches that a copolymer of vinyl halide (vinyl chloride) and an adhesion-promoting comonomer is used to produce a flexible or semi-rigid composition. The reference acknowledges that plasticizer migration in PVC polymers is an inherent limitation when good paint adhesion is required. Avoiding highly flexible PVC compositions permits the inventors to eliminate plasticizer from the composition, and copolymerizing with an adhesion promoting comonomer is said to further improve adhesion. U.S. Pat. No. 5,169,675 describes a process for the bonding of high nitrile resins to the surface of plasma-treated plastics. The "plastics" (polybutadiene rubber is also disclosed) include polyethylene, polypropylene and PVC. The reactive gas plasma is disclosed as a single gas or combination of gases including water, hydrogen, oxygen, volatile non-polymerizing alcohols and non-polymerizing organic acids, most preferably oxygen, water or combinations thereof; but not including nitrogen or acetonitrile. The use of cold gas plasma to treat polyolefins surfaces for improved paintability is described in articles by S. L. Kaplan, et al. ("Commercial Plasma Processes For Enhanced Paintability Of TPO Auto Fascia", "Successful TPO Painting-Cold Gas Plasma Advances Painting Application", and "Plasma Surface Treatment Of Plastics To Enhance Adhesion: An Overview"). These articles comprehensively describe the conditions and practical advantages of the plasma treatment process, and consequently reinforce the conclusion that the unique advance described in the present invention was missed by prior investigators. However effective the referenced treatments are initially, with certain materials, such as (PVC), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), polypropylene (PP) and other olefin polymers, the treatment's effectiveness deteriorates rapidly over time. This is especially true of polymers containing plasticizers, processing aids, internal lubricants, heat or UV stabilizers, or dispersion aids which can and tend to bleed (bloom, migrate) to the surface. This invention proves particularly effective for such classes of materials, which includes, but is not limited to, PVC, LDPE, LLDPE, PP and other polyolefin materials. SUMMARY OF THE INVENTION A process for modifying at least a portion of at least one surface of an article produced from a polymeric material, and the treated article obtained thereby, in order to improve the adhesion properties of the surface or to render the treated surface suitable for receiving and retaining all or substantial all of paint or other coating materials subsequently applied thereto. The process comprises exposing the surface to be modified to a low temperature plasma gas composition, wherein the gas composition consists essentially of a mixture of N 2 O and CO 2 , for a time sufficient to modify said surface. The thus treated surface exhibits unexpected and unusual activity and stability important for further processing and use. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a plot of surface energy in dynes/cm with respect to elapsed time in days of nonwoven fabric, the surface of which was exposed to a low temperature plasma gas consisting of N 2 O or CO 2 O or mixtures thereof at different concentrations, as the case may be. The nonwoven fabric was manufactured from a propylene-ethylene copolymer having a 2.6% polymerized ethylene content (which copolymer was produced by and is commercially available from HIMONT U.S.A., Inc.) by the spun bonded process which is well known. The spun bonded process is illustrated in, for example, U.S. Pat. Nos. 4,340,563 and 3,692,618. The disclosures of these patents is incorporated herein by reference. DETAILED DESCRIPTION OF THE INVENTION Achieving reliable paint adhesion to plastic surfaces such as thermoplastic olefins (TPOs), particularly those based on propylene polymers in general, polyvinyl halides, specifically PVC, polycarbonates and other polymers is a recurring need in the automotive and other industries. Generally, when painting olefin based plastics, adhesion promoters containing volatile organic compounds (VOCs) are used. The use of VOC containing compounds presents both health and environmental concerns. An alternative to VOC-containing adhesion promoters which is safe for both people and the environment is cold gas plasma, but obtaining improved adhesion levels and long term surface modification of PVC and propylene polymers materials are continuing objectives. These and other objectives are achieved by the present invention. Plasma is often referred to as the fourth state of matter. When energy is applied to a solid, the solid can undergo a transition to the liquid state. If further energy is applied, the liquid becomes a gas. If additional energy of the proper kind is applied, the gas dissociates and becomes a plasma. Plasmas exist in a variety of forms. Most cosmic plasmas are of a very high energy and temperature (in excess of several thousand degrees Celsius) and consequently unusable in industry and with plastics in particular. By applying the appropriate type of energy and selecting an appropriate gas environment, one can create a plasma particularly useful with plastics. For the treatment of plastics, the preferred plasma is a low pressure or vacuum process so the temperature is at or only slightly elevated above ambient, preventing thermal degradation of the plastic or thermal distortion of the molded article. Inside the plasma chamber where the polymer to be treated is present, active species in the form of electrons, free-radicals, and ions collide with the polymer surface, breaking molecular bonds and creating new functional groups on the polymer surface. Since the energy of the active species is not great enough to penetrate more than a few molecular layers of a polymer, only the surface is modified and the bulk properties of a material remain unchanged. Without being limited by theory, it is believed that there are at least three competing molecular processes or reactions which are capable of altering the polymer simultaneously, leading to a complex result: 1. Ablation: the removal by evaporation of surface material and organic contaminants, also referred to as etching; 2. Crosslinking: the chemical connection of two or more polymer chains; and 3. Activation: the substitution of atoms in the polymer molecule with chemical groups from the plasma. These reactions are affected by, and potentially controlled through, the gas chemistry and the process variables associated with a particular plasma treatment system. It is also known that plasma contains a very high-energy vacuum ultraviolet (UV) radiation. UV creates free radicals on the surface of the polymer which are identical in nature to radicals created by electron bombardment, and thus react in a similar manner to chemically modify the surface. Plasma treatment system configuration also plays an important role in processing large size parts, or large quantities of smaller parts. Barrel type plasma systems generate a "secondary plasma" in that the actual glow discharge or "primary plasma" is generated between a cylindrical, mesh sleeve and the barrel wall. Since the part to be surface treated is usually placed on a stage in the center of the barrel, diffusion of constantly depleting active species are transported to the part. A secondary plasma system is therefore inefficient due to line-of-site shadowing of various radiation, such as UV, lack of uniformity due to a radial radio frequency (RF) field effect, and differing specie densities. Preferred plasma systems for use in the present invention are the more technologically advanced, primary plasma systems which incorporate a parallel plate electrode design where parts to be treated are exposed directly to the primary field of RF energy. The subsequent primary plasma is particularly more uniform and more efficient since the part is exposed in all three dimensions to the glow discharge. With higher pressure processes (but still within the general definition of a cold gas plasma), some form of gas delivery system, designed to create a uniform laminar flow of process gas throughout the entire chamber volume is beneficial. In multiple electrode/shelf designs, it is important that each of the electrodes receive equal amounts of RF energy. In this manner a uniform glow discharge is created in between each shelf or in each plasma zone. Solid state components and microprocessor control of the systems parameters of process time, flow rate, power level, and working pressure, will also ensure process uniformity, efficiency, and repeatability. Since plasmas are electrically conductive atmospheres, they carry a characteristic impedance to the output of the RF generator. Therefore, the preferred plasma process utilizes a matching network to constantly tune the plasma impedance to the output impedance of the RF generator. Advanced plasma systems suitable for use in the present invention are available from HIMONT Plasma Science, Foster City, California (a business unit of HIMONT U.S.A., Inc.), and incorporate an automatic matching type of network and provisions for error checking during a process. The low temperature plasma is generated in a gaseous atmosphere at reduced pressure of from about 0.001 to about 10 Torr, preferably from about 0.01 to about 5 Torr, more preferably from about 0.05 to about 1.0 Torr, most preferably from about 0.125 to about 0.400 Torr. The electric power can be supplied to the equipment at a high frequency, from about 40 Khz to 3 Ghz, preferably from 13 to 27 Mhz, and most conveniently at 13.56 Mhz. To achieve the desired plasma condition in the gaseous atmosphere, the electric power delivered to the apparatus can vary over a range of from about 10 to 10,000 watts; preferably from about 50 to about 5,000 watts, more preferably from about 75 to about 1,000 watts, most preferably from about 200 to about 500 watts. The power used is somewhat dependent on chamber working volume. The most preferred 200 to 500 watts is appropriate for HIMONT Plasma Science PS0350 or PS0500 gas plasma apparatus with working volumes of 3.5 and 5.0 cubic feet, respectively. The plasma treatment time varies from a few seconds to several tens of minutes, preferably from about 20 seconds to about 30 minutes, most preferably from 20 seconds to about 7 minutes. It should be appreciated that treatment pressure, time and power are interrelated, rather than independent, variables. The effect of the level selected for each of these variables will determine the extent of polymer surface modification; also related are the chamber volume and geometry as well as the sample size and surface geometry. The selection of the level for these variables is within the ordinary skill of practitioners in the art to which this invention pertains. This invention provides a particular and unique gas combination of N 2 O and CO 2 which when used to treat polymer surfaces according to this invention provides not only a modified polymer surface but one that is time-enduring. The N 2 O/CO 2 mixtures are effective from 80 to 40 mol % N 2 O with 20 to 60 mol % CO 2 , preferably 70 to 45 mol % N 2 O/30 to 55 mol % CO 2 , most preferably from 60 to 45 mol % N 2 O/40 to 55 mol % CO 2 , where the amount of N 2 O and CO 2 in the mixture equals 100 mol %. The plasma process is generally practiced as follows. The parts to be treated are placed into a vacuum chamber and the chamber pressure is reduced, typically to 0.05 Torr. The process gas mixture employed is introduced to the chamber and the chamber pressure stabilized at a pressure of 0.5-1.0 Torr. The interior dimensions of the work area is approximately 0.33×0.41×0.44 meters (width×height×depth) for a total working volume of 0.06 cubic meters. A suitable high frequency form of energy, typically 13.56 Mhz radio frequency energy, is used to create the plasma; in the system described this is achieved with a total power input capacity of 550 watts. The RF energy dissociates the gas, creating a plasma characterized by a distinctive glow. Since the process is conducted at reduced pressures, the bulk temperature of the gas is near ambient temperature, thus the reference to a cold gas plasma, a glow discharge, or a cold gas glow discharge. The electrons or ions created in the plasma bombard the polymer's surface, abstracting atoms or breaking bonds creating free radicals. These free radicals are unstable and seek to satisfy a more stable state by reacting with free radicals or groups within the plasma gas, also establishing new moieties on the surface of the polymer. In this manner the polymer surface can be molecularly re-engineered in a highly complex manner to provide a physical state and functional groups that enhance adhesion of the paint and other coating materials and provide reactive sites that can result in covalent chemical bonding of the paint to the polymer. The modified surface condition of the plastic and covalent bonds enhance the permanency and the adhesive tenacity of the paint or coating material to the polymer. As described above, treating a polymer with plasma can increase its surface energy by modifying the surface chemistry. Greater surface energy offers the potential for greater chemical reactivity and compatibility to paints, inks and other coating materials. Enhanced surface reactivity is characterized in the laboratory by water wettability. Wettability describes the ability of a liquid to spread over and penetrate a surface, and can be measured by the contact angle between the liquid and the surface or by the use of reference liquids with known properties. The relationship between contact angle and surface energy is direct; contact angle decreases with surface energy. Contact angle measurements are sometimes also used as a general indication of the presence of contaminants. The cleaner the surface, the lower the contact angle a water drop will make with the surface. For example, a surface contaminated with mold release agent will make a contact angle of 80° to 90° , indicating poor wettability; and silicones will form a contact angle greater than 90 degrees. Many clean metal surfaces show a contact angle of 30° to 70° . On the other hand, plasma-treated surfaces yield a contact angle 20° or less, suggesting reduced contamination and/or greater surface energy. It is appreciated that bonding in manufacturing processes, including paint adhesion, is a complex and specialized field, and although cleanliness and wettability are necessary for good adhesion, such conditions do not guarantee it. Plasma treatment is a complex chemical process and the results of the operation depend on the chemistry of the surface and the chemistry of the plasma. The resultant surface chemistry must be compatible with any bonding agents, including paints. Plasma treatment of the polymers of the present invention using the gas composition taught herein provides unexpected advantages in surface condition and paint and coating adhesion. The polymers useful in the present invention are comprised of isotactic and sydiotactic propylene polymer materials, ethylene polymers, polyamides, polyesters, polystyrene, styrene copolymers containing 70% polymerized styrene units, polycarbonate, polyphenylene ether (PPE), and polyvinyl halide polymers generally and PVC in particular. Propylene polymer materials and ethylene polymers include homopolymers, copolymers and terpolymers with other alpha-olefin monomers and/or aliphatic diene monomers, and mixtures of such polymers. Suitable propylene polymer materials include (I) homopolymers of propylene; and (II) random crystalline propylene copolymers, terpolymers or both, containing from about 80 to about 98.5% of propylene; preferably about 90 to about 95%, more preferably about 92 to about 94% of propylene; and from about 1.5 to about 20.0% of at least one comonomer selected from the group consisting of ethylene and C 4 -C 10 alpha-olefins. When a C 4 -C 10 alpha-olefin is not present, the copolymer preferably contains from about 2 to about 10% ethylene, more preferably from about 7 to about 9%. When a C 4 -C 10 alpha-olefin is present, the terpolymer preferably contains from about 0.5 to about 5%, more preferably about 1 to about 3% ethylene and from about 2.5 to about 10.0%, preferably about 3 to about 7%, more preferably about 4.0 to about 6.0% of an olefin selected from the group consisting of C 4 -C 8 alpha-olefins. Included also are mixtures of such copolymers and terpolymers, with or without polypropylene homopolymer. Additionally useful propylene polymer materials are (III) heterophasic or impact-modified polyolefin compositions obtained by sequential copolymerization or mechanical blending of (I) or (II) with an elastomeric olefin copolymer or terpolymer fraction such as elastomeric ethylene-propylene, ethylene-butene-1, propylene-butene-1 copolymers, and ethylene-propylene-diene monomer terpolymers. Suitable heterophasic polyolefin compositions of this type include, for example, those described in European patent application EP A-416 379, and in European patent EP B-77 532. Suitable heterophasic polyolefin compositions identified as (III), above, can comprise (by weight): (a) 90-55 parts of polypropylene homopolymer having an isotactic index greater than 90, and/or a crystalline copolymer of propylene with ethylene and/or with an α-olefin of formula CH2═CHR, where R is a C 2 -C 6 alkyl radical, containing less than 10% of ethylene and/or α-olefin, preferably from 0.5 to 9%, more preferably from 2 to 6% by weight, and (b) 10-70 parts, preferably 20-40, of an elastomeric copolymer of propylene with ethylene or with an α-olefin of formula CH2═CHR, where R is a C 2 -C 6 alkyl radical or mixtures thereof, wherein the total of (a) and (b) is 100 parts. The C 4 -C 10 alpha-olefin is selected from the group consisting of linear and branched alpha-olefins such as, for example, 1-butene, isobutylene, 1-pentene, 1-hexene, 1-octene, 3-methyl-1-butene, 4-methyl-1-pentene, 3,4-dimethyl-1-butene and ethyl-1-hexene. The propylene polymer materials described herein, including isotactic polypropylene, random copolymers and terpolymers of propylene and their mixtures, with or without polypropylene homopolymer and the heterophasic polymer compositions are available commercially from HIMONT U.S.A., Inc. and HIMONT Italia S.r.l. Polyvinyl halide polymers useful in the present invention are well known, particularly PVC. It is produced commercially primarily as a homopolymer although copolymers are also useful. In copolymers vinyl chloride constitutes 50% by weight or more of the polymer, with one or more copolymerizable monomers selected from the group consisting of vinyl esters, such as vinyl acetate, vinyl ethers, acrylic acid and esters thereof, methacrylic acid and esters thereof, maleic acid and esters and anhydride thereof, fumaric acid and esters thereof, aromatic vinyl compounds, such as styrene, vinylidene halides, such as vinylidene chloride, acrylonitrile, methacrylonitrile and alpha-olefins, such as ethylene and propylene. Commercial PVC typically is produced by an addition polymerization process using a free radical formed by the decomposition of an initiator. Control of the polymerization temperature typically results in isothermal conditions which produces a polymer with a narrow molecular weight distribution. The polymer is partially crystalline (syndiotactic) with a significant amount of unsaturated chain ends, e.g., about 60% depending on the mode of termination. In addition, a small amount of chain branching (about 4%) can be present. PVC is susceptible to decomposition at temperatures as low as 100° C. and is sold commercially with thermal stabilizers. PVC polymer is usually mixed or compounded with other materials to make a usable product. The flexible PVC products contain varying amounts of plasticizers whereas rigid products contain little or no plasticizers. Plasticizers vary in their compatibility with PVC and are used in various concentrations depending on that compatibility. Plasticizers are susceptible to migration, e.g., bleeding or blooming to the surface, and therefore can significantly affect the adhesion and paintability of the plasticized compound, thus making the advance of the present invention particularly valuable. Typical plasticizers useful in PVC compositions include esters of phthalic acid, such as dioctyl phthalate, dibutyl phthalate and butyl benzyl phthalate, esters of aliphatic dibasic acids, such as dioctyl adipate and dibutyl sebacate, glycol esters, such as esters of pentaerythritol and diethylene glycol dibenzoate, esters of aliphatic monocarboxylic acid, such as methyl acetylricinoate, esters of phosphoric acid, such as tricresyl phosphate and triphenyl phosphate, epoxidized oils, such as epoxidized soybean and linseed oil, esters of citric acid, such as acetyltributyl citrate and acetyltrioctyl citrate, trialkyl trimellitates, tetran-octyl pyromellitate and polypropylene adipate as well as other kinds of plasticizers including polyester-based plasticizers. Other classes of additives which may be used in PVC compositions include heat resistance improvers, lubricants, stabilizers, fillers, antioxidants, ultraviolet absorbers, antistatic agents, antifogging agents, pigments, dyes, crosslinking agents, fusion promoters and lubricants for rigid PVC. In order to improve mechanical properties, e.g., impact strength, PVC polymers can be blended with other polymers, particularly elastomeric polymers, such as acrylonitrile-butadiene-styrene, urethane elastomers, ethylene-vinylacetate copolymers, acrylonitrile-butadiene copolymers, styrene-acrylonitrile copolymers, methyl methacrylate-butadiene copolymers, polyamide resins, polycaprolactams, epoxy modified polybutadiene resins and chlorinated polyethylene. When elastomeric polymers are used their concentration typically does not exceed about 50 parts by weight per 100 parts by weight of the vinyl chloride polymer. The polymer materials may be in the form of molded articles of simple or complex shapes, films, sheets, laminates, or woven or nonwoven textiles. Complex shapes are those three-dimensional articles or structures wherein the dimension along the "z" axis is greater than or equal to 10% of the dimension along either the "x" or "y" axis in the surface of the plane, such as, for example, motor vehicle bumpers and fenders. In one embodiment at least one of the polymer surfaces of the article treated according to this invention is coated with a paint composition. Typical paint compositions include acrylic enamel compositions comprising an alkyl acrylate polymer and a pigment and polyester based paint compositions containing a pigment. Such paint compositions are commercially available. The painted articles of this invention exhibit good adhesion and permanence of adhesion between the paint composition and the treated surface of the article. Over extended periods of time of normal use, the painted surface retains its initial durability and is not degraded or modified by the plasma gas mixture treated polymer surface. Examples of suitable paint compositions include Industrial Refinishing Spray Paint Acrylic Enamel "Sprayon," 01510 OSHA Blue, 01800 OSHA White and 01770 OSHA Gloss Black, all available from Sprayon Products Industrial Supply, Division of Sherwin-Williams Company. Conventional additives may be blended with the polymers used to produce the articles which can be treated according to this invention. Such additives include stabilizers, antioxidants, antislip agents, flame retardants, lubricants, fillers, coloring agents, antistatic agents and antisoiling agents. The following examples are illustrative of this invention and are not meant as a limitation of the invention disclosed and claimed herein. The mass flow controllers used in these examples were not calibrated specifically for either N 2 O or CO 2 . Flow rates were calculated based on the specific heats of the respective gases. The accuracy of the mass flow controllers in these cases is ±5%. EXAMPLE 1 Flexible PVC continuous film samples 0.020" thick and 36" wide from Davidson Rubber were treated in a Plasma Science PS0500 gas plasma reactor using the gas matrices shown in Table 1: TABLE 1______________________________________ Flow Rate Power Pressure TimeGas (SCCM*) (watts) (torr) (minutes)______________________________________N.sub.2 O 320 500 0.250 6Argon (step 1) 80 500 0.125 7N.sub.2 O (step 2) 320 500 0.250 6N.sub.2 O/CO.sub.2 200/200 500 0.250 6CO.sub.2 320 500 0.250 6______________________________________ *SCCM = Standard cc.sup.3 /min. The results are set forth in Table 1A below: TABLE 1A______________________________________ Surface Energy (dynes/cm)Time Ar(hours) N.sub.2 O N.sub.2 O N.sub.2 O/CO.sub.2 CO.sub.2______________________________________as treated 73 73 73 321 73 73 73 --2 70 70 733 70 70 734 70 70 735 70 70 736 66 66 737 66 66 738 66 62 --9 66 58 --23 42 38 --24 42 38 7325 42 38 --26 42 38 --27 38 38 --28 38 38 --29 38 38 --48 -- -- 73168 -- -- 73336 -- -- 73528 -- -- 73______________________________________ The above test results show that CO 2 alone is totally ineffective in providing a high energy surface to the article and that N 2 O alone is unable to provide a long lasting benefit. Electron spectroscopy for chemical analysis (ESCA) data was obtained on the untreated PVC samples and on the 50/50 ratio, N 2 O/CO 2 gas mixture-plasma treated PVC samples. The results are set forth in Table 1B below: TABLE 1B______________________________________ P C1 C Cd O Ba Zn N______________________________________Untreated 0.4 11.0 79.0 0.8 9.2 0.2 0.2 --PVCN.sub.2 O/CO.sub.2 0.5 4.1 77.0 0.2 18.0 -- -- 0.8Treated PVC______________________________________ These results indicate that plasma N 2 O/CO 2 gas mixture treatment has modified the sample surface at least by removing chlorine from the surface and incorporating oxygen moieties into the surface. EXAMPLE 2 The same untreated PVC film as used in Example 1 was cut into 1×2 inch strips by 36" (0.020" thick) and plasma treated with a 50/50 molar ratio of N 2 O/CO 2 . The amount of gas was varied to effect chamber pressure but ratio of the gas mixture was held constant at 50/50 molar in 5 different runs of 2 strips per run as set forth in Table 2: TABLE 2______________________________________ Power Pressure TimeRun No. (watts) (Torr) (minutes)______________________________________1 100 0.250 3.52 500 0.250 6.03 500 0.250 1.04 300 0.400 6.05 300 0.100 6.0______________________________________ After the plasma treatment, the samples were separated into two sets. The first set of samples were bonded immediately using 3M's 2216 epoxy adhesive and cure baked in accordance with the manufacturer's recommendations. The second set was bonded 120 days after the plasma treatment. The results are shown in Table 2A: TABLE 2A______________________________________Run No. Same Day Aged 120 Days______________________________________1 Cohesive Failure Adhesive Failure2 Cohesive Failure Cohesive Failure3 Cohesive Failure Adhesive Failure4 Cohesive Failure Cohesive Failure5 Cohesive Failure Cohesive Failure______________________________________ EXAMPLE 3 Black, blow-molded bottles, produced from Fina 7251 blow molding grade propylene-ethylene copolymer pigmented with 6 weight % black color concentrate, were treated in PS0500 gas plasma reactor using various gas plasma matices to investigate the enhancement of acrylic decorative ink adhesion as set forth in Table 3 below: TABLE 3______________________________________ Power Pressure TimeRun No. Gas (watts) (torr) (seconds)______________________________________1 N.sub.2 O 200 400 602 O.sub.2 200 400 303 O.sub.2 /CF.sub.4 200 400 304 Air 200 400 305 Argon 200 400 306 N.sub.2 O/CO.sub.2 * 200 400 30______________________________________ *50/50 mol ratio *50/50 mol ratio The improvement in adhesion was determined according to the ASTM D 3359-B tape pull test using 3M 810, 616, and 600 tapes on cross hatched specimens. The results are set forth in Table 3A below: TABLE 3A______________________________________ Run No. Results______________________________________ 1 20% pass 2 70% pass 3 50% pass 4 0% pass 5 10% pass 6 100% pass______________________________________ The above results show the unexpected and superior performance of the N 2 O/CO 2 gas plasma. EXAMPLE 4 To determine the sensitivity of the N 2 O and CO 2 alone and mixtures thereof at different concentrations, nonwoven fabric as described herein before was examined at 150 watts and 0,150 Torr. The results are shown in FIG. 1. The expression "consisting essentially of" as used in this specification excludes unspecified ingredients which affect the basic and novel characteristics of the claimed invention. Other features, advantages and embodiments of the invention disclosed herein will be readily apparent to those exercising ordinary skill after reading the foregoing disclosures. In this regard, while specific embodiments of the invention have been described in considerable detail, variations and modifications of these embodiments can be effected without departing from the spirit and scope of the invention as described and claimed.

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CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims priority in U.S. Provisional Patent Application No. 61/595,536, filed Feb. 6, 2012, which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to satellite communication systems and, more particularly, to such a system which communicates from a communication hub to a remote station on one band and from the remote station to the hub on another band. [0004] 2. Description of the Related Art [0005] Modern telecommunication systems provide means for communicating vocal conversations, email, and various kinds of data from originating sources to destinations over twisted pair landlines, coaxial cables, fiber optic cables, and radio frequency communication links. Satellite communications have become an important mode of communications for large and small entities for both one-way services, such as television signals, and two-way services such as data processing services, satellite internet services, and the like. Two-way communication satellite services are typically set up as a head-end or hub station which is interfaced to a large scale communication network, such as the public switched telephone network (PSTN) infrastructure, and remote stations which communicate through a communication satellite to the hub station and through the hub station to the PSTN. The PSTN provides conventional telephone services and data communication over dedicated lines, the internet, and other links. Equipment for remote satellite stations has evolved to what is known as VSAT or very small aperture terminal satellite dishes. [0006] The present standard for VSAT satellite communications is the use of Ku band (12 to 18 GHz) satellite technology in order to use meter or sub-meter sized satellite antennas and to avoid costly licensing and frequency coordination. The problem with Ku band satellite technology is that it is highly susceptible to local rain or weather fade due to the nature of the frequencies used. For this reason, networks have to be tolerant of frequent signal fades or outages during the presence of rain, snow, and storm clouds. This occurs in all Ku band transmissions whether it is for residential satellite television or VSATs. [0007] Some networks attempt to mitigate the fade through the use of automatic uplink power control at the customer VSAT location. This technology gradually increases the transmit power at the remote customer location via a command from the hub location when the hub location senses that there is attenuation somewhere in the path between the remote location and the hub. This works some of the time quite well, but the same local weather anomaly that causes the problem with the inbound signal to the hub also creates a problem with the outbound power control signal to the remote site. Eventually, the control signal cannot reach the remote site electronics with sufficient strength and the remote site shuts down until it can receive a valid command. [0008] This is very bad for reliability and, as a result, Ku band networks are generally designed to be out of service for about 50 hours per year due to weather. For government and customer applications that need to know weather and other critical information, these 50 hours of down time cannot be tolerated. [0009] Heretofore there has not been available a dual-band satellite communications system with the features and elements of the present invention. SUMMARY OF THE INVENTION [0010] The present invention provides a hybrid satellite communication system in which a hub station transmits signals to remote stations through a satellite at a relatively low frequency which is unaffected by weather effects and in which the remote stations transmit signals to the hub station at a relatively higher frequency which enables the use of more economical equipment at the remote stations. The hub station senses the signal quality or strength received from each remote station and transmits power control signals to remote stations with poor signal strengths to cause such remote stations to increase their output power to overcome weather effects. The power control signals are transmitted on the lower frequency to prevent the power control signals from being masked by the weather effects. [0011] An embodiment of the present invention provides a technique to send the outbound signals from the hub at a much lower C band (4 to 8 GHz) frequency that is virtually unaffected by weather via the same satellite that is receiving a Ku band signal from the remote site. As a consequence, the remote site never or nearly never loses its control signal and is always changing its power in response to weather effects to thereby eliminate outages. This requires judicious selection of satellite transponders, special antennas, and specially designed feeds that allow simultaneous transmission of Ku band while receiving C band. [0012] An embodiment of the present invention provides a hybrid satellite antenna for the remote stations to enable the remote station to transmit and receive signals on different bands using a single antenna assembly. [0013] An embodiment of the present invention employs an offset feed/clear aperture antenna dish to enable the use of a reduced size dish without causing interference effects by receiving signals from or transmitting signals to multiple satellites. [0014] Various objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. BRIEF DESCRIPTION OF THE DRAWINGS [0015] The drawings constitute a part of this specification and include exemplary embodiments of the present invention illustrating various objects and features thereof. [0016] FIG. 1 diagrammatic view illustrating an embodiment of a hybrid C/Ku band satellite communication system. [0017] FIG. 2 is a block diagram illustrating components of an embodiment of the present invention. [0018] FIG. 3 is a side elevational view of an axial feed antenna dish which may be employed in an embodiment of the present invention. [0019] FIG. 4 is a side elevational view of an offset feed, clear aperture antenna dish which may be employed in an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS I. Introduction and Environment [0020] As required, detailed aspects of the present invention are disclosed herein, however, it is to be understood that the disclosed aspects are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art how to variously employ the present invention in virtually any appropriately detailed structure. [0021] Certain terminology will be used in the following description for convenience in reference only and will not be limiting. For example, up, down, front, back, right and left refer to the invention as orientated in the view being referred to. The words, “inwardly” and “outwardly” refer to directions toward and away from, respectively, the geometric center of the aspect being described and designated parts thereof. Forwardly and rearwardly are generally in reference to the direction of travel, if appropriate. Said terminology will include the words specifically mentioned, derivatives thereof and words of similar meaning. II. Hybrid Dual-Band Satellite Communication System 1 [0022] Referring to the drawings in more detail, the reference numeral 1 generally designates an embodiment of a hybrid C/Ku band satellite communication system according to the present invention. The illustrated system 1 generally includes a satellite teleport facility or hub station 3 which communicates with a plurality of remote stations 5 by means of a geostationary communication satellite 7 . The hub station 3 is interfaced to a large scale communication network, such as the public switched telephone and data network (PSTN) 9 which provides telephone and data communication services. The remote stations 5 include communication devices, such as computers 12 and telephones 14 , which communicate with the PSTN 9 by way of the system 1 . [0023] Referring to FIGS. 1 and 2 , the illustrated hub station 3 includes a hub server 17 which is a processor or computer that controls the flow of data through the hub station 3 . The hub server 17 includes network interface circuitry 19 which interfaces the hub server 17 to the PSTN 9 . The illustrated hub station 3 includes a C band transmitter 21 which receives data from the hub server 17 and transmits the data through a C band antenna 23 to the satellite 7 on a C band frequency in the range of about 3.7 to 4.2 GHz. The hub station 3 includes a Ku band receiver 25 which receives data from a Ku band antenna 27 from the satellite 7 on a Ku band frequency in the range, as illustrated, of about 14 to 14.5 GHz. The transmitter 21 and receiver 25 are interfaced to the hub server 17 . [0024] Each remote station 5 includes a remote server 30 which is a processor or computer that controls the flow of data through the remote station 5 . The remote station 5 includes interface circuitry 32 to interface the remote server 30 to the computers 12 and telephone sets 14 communicating therewith. The illustrated remote server 30 outputs data to the satellite 7 through a Ku band transmitter 34 and a hybrid C/Ku band antenna 36 on the same Ku band frequency range as the hub receiver 25 and receives data from the satellite 7 through the hybrid antenna 36 through a C band receiver 38 on the same C band frequency range as the hub transmitter 21 . The use of the hybrid antenna 36 economizes the implementation of the remote station 5 as far as the purchase and mounting of an antenna and wiring therefor. [0025] The illustrated satellite 7 shown in FIG. 1 carries a plurality of C band and Ku band transponders (not shown). The transmission of signals from the hub station 3 and the satellite 7 on C band frequencies assures that such signals will reach the remote station 5 , since the C band range of frequencies are virtually immune to deterioration from weather effects. The hub server 17 monitors the signal quality of the Ku band signals received from the remote stations 5 . The output power of the remote Ku band transmitter 34 can be controlled by the remote server 30 to increase or decrease as needed to provide reliable signal quality from the remote station 5 to the satellite 7 and from there to the hub station 3 . The hub server 17 can control a remote server 30 to increase the output power of its transmitter 34 by an uplink power control UPC signal to overcome deterioration or fade of the signal from the remote station 5 due to weather effects. The UPC signal is sent at the C band frequency range to assure that it is received by the remote station 5 . [0026] A geostationary satellite 7 is a satellite which has an orbital period equal to the Earth's rotational period (one sidereal day), and thus appears motionless, at a fixed position in the sky, to ground observers. A geostationary orbit can only be achieved by locating a satellite at an altitude very close to 35,786 km (22,236 mi) above the surface of the earth and directly above the equator. Communications satellites and weather satellites are often given geostationary orbits so that the ground antennas that communicate with them do not have to move to track them, but can be pointed permanently at the position in the sky where they stay. Because of efforts to maximize the coverage of geostationary satellites, there tend to be clusters of closely spaced satellites positioned over the equator to serve national or continental areas, such as the North American continent from coast to coast. However, there is a limit to how closely satellites can be spaced to avoid interference issues when using economical sized antenna dishes on the ground. Currently, the minimum spacing is about two degrees of arc. [0027] Smaller sized dishes tend to be more economical than larger dishes and require less rugged mounting structure. However, smaller dishes have larger beam angles than larger dishes. The larger beam angle of a small dish may receive signals from two or more adjacent satellites and transmit signals to two or more satellites. The reception of signals from multiple sources either at the satellite or ground station may be interpreted as interference and cause undesired effects. [0028] Referring to FIG. 3 , a common type of dish for communicating with satellites is an axial feed dish 42 which has a feed assembly 44 located along the axis 46 of the dish 42 . Typically, the dish 42 is oriented to intersect the axis 46 thereof with the satellite with which it is intended to communicate. The axial feed dish 42 has no simple mechanism for avoiding transmitting to or receiving from multiple satellites if the size is reduced below a certain diameter. Thus an axial feed dish such as the dish 42 must be sized large enough to control its beam angle. [0029] Referring to FIG. 4 , an embodiment of the system 1 employs an offset feed/clear aperture dish 50 as the hybrid antenna 36 . The dish 50 has a feed assembly 52 located at an angle which is offset from the axis 54 thereof. The illustrated dish 50 is nominally a 2.4 meter dish and is appropriate for use on both C band and Ku band frequencies. The dish 50 is referred to as a clear aperture type dish because the offset feed assembly 52 does not block energy reflected from the dish surface, as can occur with an axial feed dish 42 . The dish 50 may be implemented as a 2.4 meter Model 1244 or 1251 dish manufactured by Prodelin Corporation (www.prodelin.com). Alternatively, other types of dishes may be used, such as the 3.8 meter Model 1383, also manufactured by Prodelin. The feed assembly 52 is a dual band feed assembly which is designed to receive in a C band frequency range and transmit in a Ku band range. The feed assembly 52 may be implemented as a Prodelin Model 0800-4487-1 or the like. The illustrated feed assembly 52 is supported by struts 56 and 58 in spaced and angled relation to the surface of the dish 50 to radiate radio frequency energy toward the dish 50 or to receive energy reflected from the dish 50 . [0030] Because the feed assembly 52 is angularly offset from the axis 54 , aiming of the dish 50 toward the satellite 7 is complicated somewhat, since the surface of the dish 50 must be angled in such a manner as to reflect the signal energy from the satellite toward the feed assembly 52 and from the feed assembly 52 toward the satellite. However, the offset feed dish 50 can be used to reduce the multiple satellite interference effect of the beamwidth thereof, such that a smaller size dish can be used than would otherwise be possible. [0031] While the system 1 has been described using C band frequencies from the hub station 3 to the remote stations 5 and Ku band frequencies from the remote stations 5 back to the hub 3 , it is foreseen that other sets of bands could be employed, such as Ka band frequencies (26.5 to 40 GHz) from the remote stations 5 to the hub station 3 . [0032] It is to be understood that the invention can be embodied in various forms, and is not to be limited to the examples discussed above. The range of components and configurations which can be utilized in the practice of the present invention is virtually unlimited.

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FIELD The present mechanisms and methods generally relate to window systems, and specifically to latch mechanisms for slidable windows. BACKGROUND Work vehicles, such as tractors, combines, front-end loaders, excavators, and the like, typically have enclosed cabs with large window assemblies to provide ventilation and to allow an operator a good view of their work environment. Frequently, these window assemblies provide multiple fixed and/or movable window panes within a perimeter frame. In the art, during vehicle assembly, a window assembly can be attached to a body side wall as a single complete unit or in pieces. In most instances the window assembly is permanently attached from the outside of the vehicle by its perimeter frame with a weatherproof seal using compressible sealing rings, adhesives, and the like. Protective caging can also be added to the outside surface of the window assembly to protect window panes and the vehicle operator from stray impact. Often these types of window assemblies have at least one slidable panel, such as a slidable window pane. Given the sometimes extreme work environment to which these window assemblies are exposed, it is desirable to secure the window pane from unintended travel along its path. Therefore, latch mechanisms associated with the slidable aspect of a window pane should provide a simple and rugged design to not only facilitate ease of movement of the window pane, but also to provide a means to secure the window in place at a plurality of positions along its travel path. Known in the art are latching mechanisms for slidable windows that attach to a window pane corner or corners. For example, the latching mechanism can restrict window pane movement through the use of a locking pin on the latching mechanism that can selectively engage any one of a plurality of locking pin openings within a window assembly frame along its travel path. In one embodiment, the latching mechanism can be disengaged by squeezing two lever elements together to withdraw the locking pin from the window assembly frame. Other embodiments can provide two corner latching mechanisms that can require a user to simultaneously slide spring loaded locking pins out of the window frame. These types of mechanisms are common on windows with vertical travel paths. Unfortunately, latching mechanisms positioned on a window pane corner can be difficult to operate (such as when a user is wearing gloves). Also, the window may bind during attempted travel. For example, this racking condition can occur when a user grabs the latching mechanism to unlatch the locking pin and push or pull the window to a new position. Specifically, the reactive moment causes a rotational value instead of a straight line pull. Overcoming the rotational effects of a corner pull may require an operator to use both hands to complete window movement. The same is true for dual latching mechanism on two corners of the same window pane. Attempts to overcome the shortcomings of the rotational effect to a window as it travels along its path can provide a simple latching mechanism on or about the center of a window pane edge perpendicular to its travel path (e.g., along a vertical axis of a horizontally sliding window pane). See generally, U.S. Pat. No. 7,036,851 to Romig and EP 1 700 979 B1 to Jurgen et al. These solutions are not complete though in that it typically only retains movement of the window pane in its closed position and/or provides a complicated mechanism which may be a maintenance issue for window assemblies in harsh working environments. Thus, despite the advances of the current state of the art, further improvements in window latch mechanisms for slidable windows are possible and desired. SUMMARY Accordingly, there is provided herein latch mechanism embodiments for a slidable window that overcomes the noted deficiencies in the art. Specifically, the present embodiments provide latch mechanisms for a slidable window generally disposed about the center of mass of a window pane on an edge perpendicular to its travel path. The present embodiments provide a balanced straight line pull using minimal mechanical effort and to provide a plurality of latch points to selectively secure a window pane in place along its travel path. A preferred embodiment provides a latch assembly for a window having first and second parallel edges slidably disposed between parallel first and second guiderails of a frame and can have a housing attached to a third window edge perpendicular to the first and second parallel sides, a latch handle connected to a drive gear engaged to a locking element slidably disposed within a channel of a housing in response to rotation of the drive gear about a pivot; the locking element movable from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the first guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the locking element in the operational position. In some embodiments, the bias can be achieved by a compression spring, a coil spring, rubber, or an elastic polymer applying a compressive force to a second end of the locking element. In some embodiments, the latch handle can be a single lever having an orientation angle of about 25 to 45 degrees from the axis of the third window edge in an operating position. Optional features can include a plurality of view holes adjacent to the plurality of recesses spaced along the window travel. The locking element can also be a wire-wound non-compressible cable. Preferably, the latch handle is positioned to correspond to the center of mass along the third edge of the window, whereby a balanced pull-line is achieved. In another embodiment, a second locking element can be provided to mirror the first locking element in an opposite direction from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the second guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the second locking element in the operational position. Other preferred embodiments provide a window assembly that can have a window having first and second parallel edges slidably disposed between parallel first and second guiderails of a frame; a latch assembly having a housing attached to a window edge perpendicular to the first and second parallel sides, the latch assembly having a latch handle connected to a drive gear engaged to a locking element slidably disposed within a channel of a housing in response to rotation of the drive gear about a pivot; the locking element movable from a biased extended position to a retracted position in response to rotation of the drive gear by a force sufficient to overcome the bias; and the first guiderail having a plurality of recesses spaced along the window travel path to receive the first end of the locking element in the operational position. The guiderails can be horizontal. Other features will become more apparent to persons having ordinary skill in the art to which pertains from the following description and claims. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing features, as well as other features, will become apparent with reference to the description and Figures below, in which like numerals represent elements, and in which: FIG. 1 is a perspective view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. FIG. 2 is a cutaway view of a latch mechanism for a sliding window according to the present embodiments in a latched ( 2 A) and unlatched ( 2 B) position. FIG. 3 is a side view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. FIG. 4 is an end view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. FIG. 5 is a side view of a window assembly having a latch mechanism for a sliding window according to the present embodiments in various latched positions. FIG. 6 is an exploded perspective view of a window assembly having a latch mechanism for a sliding window according to the present embodiments. FIG. 7 is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines A-A in FIG. 3 in an operational mode. FIG. 8 is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines B-B in FIG. 3 in an unlatched mode. FIG. 9 is a side view of a latch mechanism for a sliding window according to the present embodiments in a latched position. FIG. 10 is a side view of a latch mechanism for a sliding window according to the present embodiments in an unlatched position. FIG. 11 is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines C-C in FIG. 9 in an operational mode. FIG. 12 is a sectional view of a window assembly latching mechanism according to the present embodiments taken along section lines D-D in FIG. 10 in an unlatched mode. DETAILED DESCRIPTION The present embodiments provide latch mechanisms for a slidable window generally disposed about the center of mass of a window pane on an edge perpendicular to its travel path. The present embodiments provide a balanced straight line pull using minimal mechanical effort and to provide a plurality of latch points to selectively secure a window pane in place along its travel path. The present embodiments provide easy travel and easy latching/unlatching of a slidable window unit, which has multiple latching points along its path of travel. The mechanisms are simple to manufacture, easy to maintain and easy to operate. Although the illustrated embodiments are described for a horizontally slidable window assembly for a work vehicle, it is noted that many other applications and embodiments are possible within the scope of its elements, including vertically slidable window panes. Further, for ease of understanding the present embodiments, only one latch pin is illustrated, though dual latching pins travelling to opposite ends of a window pane are also possible. In one embodiment, a pull and engage/disengage feature is centered on a generally square window pane. The preferred point of the pull and engage/disengage feature is on a window pane edge that is perpendicular to its travel path, and specifically at a location on the edge that is centered to the center of mass of the window pane. Factors that can alter direct center placement of the pull and engage/disengage feature can include the geometry of the window (which alters the location of the center of mass) and the coefficient of friction of the window pane against its upper and lower seals. As such, the present embodiments preferably provide a straight line pull to eliminate a racking condition while the window pane slides. This can allow one handed operation. Reduction and/or elimination of the racking condition allows longer life of the window seals, thus reducing maintenance costs and vehicle down time. Ease of use can further be improved through the use of a window latch lever that is easy to grasp, even if a user is wearing gloves. This is provided through the preferred illustrated embodiments of the window latch lever that is sized, shaped, and positioned to allow greatly improved ease of use over the art. Because a single lever is employed, pinching of components is eliminated, thus reducing risk of injury to an operator. The present embodiments still allow for a latching pin to be deployed into a latch pin opening along the window assembly perimeter frame. Preferred embodiments provide for multiple openings along its travel path within the perimeter frame to provide a plurality of secured positions, whether opened or closed. Turning now to the Figures. Shown are the present embodiments incorporated into a large window assembly for a work vehicle. In the art, removal of large window assemblies is difficult due to their inherent size and weight. Typical configurations can include three window panes including a lower fixed pane and two upper split panes. Optionally, some panes may be slidable along a track to provide ventilation. Also, protection against stray impact to these assemblies can be included through fixed caging. Generally, one embodiment of the present design is provided for a three glass panel window unit assembly with a center bar separating two upper panels from a fixed lower panel and is generally indicated at 20 in the Figures. The window unit can be attached to any number of wall openings in a variety of applications. Preferably, the wall is upright. As shown in FIG. 1 , window unit 20 is preferably formed by a perimeter frame 24 that is fused at all joints. Perimeter frame 24 can be formed from extruded aluminum, composites, plastics, other metals, and combinations thereof. In the illustrated embodiment of FIG. 1 , two break points 60 and 62 are shown in perimeter frame 24 . Break points 60 and 62 can be sealed by any means to provide a weatherproof seal, and can include welding (such as arc welding or spot welding), gluing, or use of fastening means, such as screws, rivets, and the like. Where fastening means are used, a powder coating over fastened break points 60 and 62 can provide additional weatherproof sealing. Perimeter frame 24 can have an interior channel 66 configured to receive a perimeter channel seal 58 . Perimeter channel seal 58 (and all seals to the window panes) can be made of an elastomeric substance suited to provide a friction fit and weather tight seal for window unit 20 window panes. The friction fit is also configured to allow a user to be able to remove the glass pane without use of additional tools and in some instances allow a window pane to slide to create an opening. For illustrative purposes, the embodiments of the present window unit provide two upper panes 22 a and 22 b , and a lower pane 22 c . Panes 22 can be held stationary in the assembled position by perimeter seal 58 and a center bar 26 . Pane 22 a can be held on its lower edge within center bar 26 channel having seal 41 . Pane 22 a can also be held in place along its upper edge by a perimeter seal. Pane 22 b can be held stationary on its lower edge within center bar 26 channel having seal 43 and along its top edge by a second perimeter seal. Pane 22 c can be held in place on its upper edge by seal 42 disposed within a lower center bar channel. Again, seals 40 , 41 and 42 provide a friction fit to hold the pane in place and provide a weather tight seal. Also, as shown, pane 22 a is slideable from a closed position to an open position 68 (See FIGS. 3 and 5 ). Therefore seal 42 friction fit should allow a user to slide pane 22 a from an open and closed position while maintaining a seal against weather. Stop 124 (See FIG. 6 ) prevents opening pane 22 a past a predetermined point. In this case, stop 124 is configured to be ahead of the radius 126 in the upper corner of perimeter frame 24 . As shown in the Figures, the latching mechanism of the present embodiments can be positioned on a housing bar 82 that can be permanently affixed to pane 22 a on its reward vertical edge and can have weather tight seal edge 84 to seal the area between panes 22 a and 22 b . As shown in FIGS. 7 and 8 , pane 22 a can be attached to housing bar 82 by an adhesive within a channel 120 . As illustrated, pane 22 a can be held secured in place along its travel path by use of a latching mechanism actuated by window latch handle 34 . Latch handle 34 can be closed ( FIG. 1 ) in an operational mode to engage a latch pin 78 in a latch pin recess/opening 114 within perimeter frame 24 to restrict pane 22 a from sliding, or to an open position 34 a ( FIG. 1 ) to retract latch pin 78 from opening 114 . Thus, pane 22 a can be held in place by a window latch pin 78 , which can be actuated to be inserted into a plurality of perimeter frame 24 latch holes 114 . It is noted that the present window configuration is for illustration purposes only and other possible configurations are possible as to the number of window panes and openability of those panes. The latching mechanisms of the present embodiments are thus a housing bar 82 attached to pane 22 a as shown generally in FIG. 1 with a seal 84 to provide a weather seal between panes 22 a and 22 b . A latch handle 34 actuates the release of a latch pin 78 within a latch pin hole 114 in perimeter seal 24 . Latch handle 34 is sized, shaped, and positioned to allow greatly improved ease of use. As shown, latch handle 34 is a single lever that in its operational position extends beyond housing bar 82 at an angle (approximately 20 to 160 degrees from the axis of housing bar 82 , and preferably about 30 to 45 degrees) to allow easy grasping by a user, even if gloves are worn. Latch handle 34 is also preferably positioned to have a straight line pull to slide pane 22 a . Thus, latch handle 34 is preferably placed along a window pane edge that is generally perpendicular to its travel path, and specifically at a location on that edge that is about center to the center of mass of the window pane. Factors that can alter direct center placement of the pull and engage/disengage feature can include the geometry of the window (which alters the location of the center of mass) and the coefficient of friction of the window pane within its upper and lower seals. Thus, as illustrated, latch handle 34 provides a straight line pull to eliminate a racking condition (rotational/tilting torque) while the window pane 22 a slides. The latching mechanism (e.g., using a rack and pinion) to engage a latching pin 78 within latch pin hole 114 is disposed within a channel 116 of housing bar 82 . As shown in FIG. 2 , latch handle 34 connects to a drive gear 110 disposed within channel 116 , which are both pivotable/rotatable around an axis of pivot point 112 . Adjacent and engaged to drive locking element 110 such as a wire-wound 130 compression resistant cable 108 retained within channel 116 . A first end of cable 108 can include a latch pin/tip 78 sized to be received within latch pin hole 114 . It is noted that latch pin 78 can be a separate tip, such as swedged metal or plastic, but is preferably a tip 114 formed by applying a plastic or metal material on the cable terminal end, such as dipping in a metal or plastic bath. Optionally, latch pin/tip can be a brightly visible color, such as red, which can be viewed through an optional view hole 80 to confirm that tip 78 is engaged within any of the plurality of latch pin holes 114 . Further, evidence of movement of locking element 110 can be viewable through another set of optional view holes 128 along the axis of housing bar 82 . Cable 108 is biased into latch pin hole 114 by a compression spring 122 at a second cable end. Compression spring 122 provides sufficient force (e.g., about 5-20 pounds of compressive force) to drive locking element (cable 108 ) into the frame recess 114 when latch handle 34 is released and to bias cable 108 to remain in recess 114 during vehicle operation. Compressive force of the bias should also be configured to allow a user to overcome the bias with the latch handle 34 with one hand. Thus, the operational mode of the mechanism is to bias latch pin 78 into hole 114 and to hold latch handle 34 to its angled position. Drive gear 110 is positioned so that as latch handle 34 is rotated downward cable 108 withdraws/disengages from latch pin hole 114 . As shown, drive gear pivot point 112 is on the opposite side of latch handle 34 . Once disengaged, a user can maintain a grip on the latch lever to slide pane 22 a to a desired position, where the latch handle can be released. Once released, a user can confirm that pane 22 a is secured in place by viewing latch pin tip 78 through any of the viewing holes 80 or by the angled position of latch handle 34 . The illustrated examples of the present latching mechanisms are for illustrative purposes of preferred embodiments. Many variations are possible though within the scope of these embodiments. For example, locking element 108 is shown using wire-wound cable, which is readily available as it is used for many sunroof mechanisms. Nevertheless, rods with corresponding gear teeth engaging drive gear 112 are possible. Latch handle 34 could be a twist knob with colors or indicators showing the position of the locking element 108 . Also, other means to bias cable 108 into latch pin hole 114 , such as a coil spring, rubber or elastic polymers. While the embodiments and methods have been described in conjunction with specific embodiments, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description.

4y

This application is a division of application Ser. No. 07/513,782, filed Apr. 24, 1990, which is a division of application Ser. No. 07/252,645, filed Oct. 3, 1988 now U.S. Pat. No. 4,938,763. BACKGROUND OF THE INVENTION The present invention relates to a method and composition for producing biodegradable polymers, and more particularly to the use of such polymers for providing syringeable, in-situ forming, solid, biodegradable implants. Biodegradable polymers have been used for many years in medical applications. These include sutures, surgical clips, staples, implants, and drug delivery systems. The majority of these biodegradable polymers have been thermoplastic materials based upon glycolide, lactide, ε-caprolactone, and copolymers thereof. Typical examples are the polyglycolide sutures described in U.S. Pat. No. 3,297,033 to Schmitt, the poly(L-lactide-co-glycolide) sutures described in U.S. Pat. No. 3,636,956 to Schneider, the poly(L-lactide-co-glycolide) surgical clips and staples described in U.S. Pat. No. 4,523,591 to Kaplan et al., and the drug-delivery systems described in U.S. Pat. No. 3,773,919 to Boswell et al., U.S. Pat. No. 3,887,699 to Yolles, U.S. Pat. No. 4,155,992 to Schmitt, U.S. Pat. No. 4,379,138 to Pitt et al., and U.S. Pat. Nos. 4,130,639 and 4,186,189 to Shalaby et al. All of the biodegradable polymers described in these patents are thermoplastic materials. Consequently, they can be heated and formed into various shapes such as fibers, clips, staples, pins, films, etc. Only when heated above their melting point do these polymers become liquid. During their normal use, they are solids. Thermoset biodegradable polymers have also been previously described for use in medical applications. These polymers have been formed by crosslinking reactions which lead to high-molecular-weight materials that do not melt or form flowable liquids at high temperatures. Typical examples of these materials are the crosslinked polyurethanes described in U.S. Pat. No. 2,933,477 to Hostettler and U.S. Pat. No. 3,186,971 to Hostettler et al. Copolymers based on ε-caprolactone and L-lactide or DL-lactide crosslinked via peroxide initiators were described in U.S. Pat. Nos. 4,045,418 and 4,057,537, both to Sinclair. Crosslinked caprolactone copolymers have been prepared by incorporation of a bislactone into a monomer feed, as described in U.S. Pat. No. 4,379,138 to Pitt et al. Trihydroxy-functional copolymers of ε-caprolactone and ε-valerolactone have been crosslinked with diisocyanates, thereby affording biodegradable polymers, as described in Pitt et al., J. Polym. Sci.: Part A: Polym Chem. 25: 955-966; 1987. These polymers are also solids when crosslinked or cured. Although these two classes of biodegradable polymers have many useful biomedical applications, there are several important limitations to their use in the body where body is defined as that of humans, animals, birds, fish, and reptiles. Because these polymers are solids, all instances involving their use have required initially forming the polymeric structures outside the body, followed by insertion of the solid structure into the body. For example, sutures, clips, and staples are all formed from thermoplastic biodegradable polymers prior to use. When inserted into the body, they retain their original shape rather than flow to fill voids or cavities where they may be most needed. Similarly, drug-delivery systems using these biodegradable polymers have to be formed outside the body. In such instances, the drug is incorporated into the polymer and the mixture shaped into a certain form such a cylinder, disc, or fiber for implantation. With such solid implants, the drug-delivery system has to be inserted into the body through an incision. These incisions are often larger than desired by the medical profession and lead to a reluctance of the patients to accept such an implant or drug-delivery system. The only way to avoid the incision with these polymers is to inject them as small particles, microspheres, or microcapsules. These may or may not contain a drug which can be released into the body. Although these small particles can be injected into the body with a syringe, they do not always satisfy the demand for a biodegradable implant. Because they are particles, they do not form a continuous film or solid implant with the structural integrity needed for certain prostheses. When inserted into certain body cavities such as the mouth, a periodontal pocket, the eye, or the vagina where there is considerable fluid flow, these small particles, microspheres, or microcapsules are poorly retained because of their small size and discontinuous nature. In addition, microspheres or microcapsules prepared from these polymers and containing drugs for release into the body are sometimes difficult to produce on a large scale, and their storage and injection characteristics present problems. Furthermore, one other major limitation of the microcapsule or small-particle system is their lack of reversibility without extensive surgical intervention. That is, if there are complications after they have been injected, it is considerably more difficult to remove them from the body than with solid implants. Therefore, there exists a need for a method and composition which provides a biodegradable, polymeric structure useful in overcoming the above-described limitations. There exists a further need for a method and composition for providing syringeable, in-situ forming, solid, biodegradable implants which can be used as prosthetic devices and/or controlled delivery systems. Moreover, there exists a need for such a method and composition which can provide implants having a range of properties from soft to rigid, so as to be usable with both soft and hard tissue. SUMMARY OF THE PRESENT INVENTION The present invention relates to the production and use of biodegradable polymers as prosthetic implants and controlled-release, drug-delivery systems which can be administered as liquids via, for example, a syringe and needle, but which coagulate or cure ("set") shortly after dosing to form a solid. The implants are biodegradable because they are made from biodegradable polymers and copolymers comprising two types of polymer systems: thermoplastic and thermosetting. A thermoplastic system is provided in which a solid, linear-chain, biodegradable polymer or copolymer is dissolved in a solvent, which is nontoxic and water miscible, to form a liquid solution. Once the polymer solution is placed into the body where there is sufficient water, the solvent dissipates or diffuses away from the polymer, leaving the polymer to coagulate or solidify into a solid structure. The placement of the solution can be anywhere within the body, including soft tissue such as muscle or fat, hard tissue such as bone, or a cavity such as the periodontal, oral, vaginal, rectal, nasal, or a pocket such as a periodontal pocket or the cul-de-sac of the eye. For drug-delivery systems, the biologically active agent is added to the polymer solution where it is either dissolved to form a homogeneous solution or dispersed to form a suspension or dispersion of drug within the polymeric solution. When the polymer solution is exposed to body fluids or water, the solvent diffuses away from the polymer-drug mixture and water diffuses into the mixture where it coagulates the polymer thereby trapping or encapsulating the drug within the polymeric matrix as the implant solidifies. The release of the drug then follows the general rules for diffusion or dissolution of a drug from within a polymeric matrix. Another embodiment of the invention is also provided, namely, a thermosetting system comprising the synthesis of crosslinkable polymers which are biodegradable and which can be formed and cured in-situ. The thermosetting system comprises reactive, liquid, oligomeric polymers which contain no solvents and which cure in place to form solids, usually with the addition of a curing catalyst. The multifunctional polymers useful in the thermosetting system are first synthesized via copolymerization of either DL-lactide or L-lactide with ε-caprolactone using a multifunctional polyol initiator and a catalyst to form polyol-terminated prepolymers. The polyol-terminated prepolymers are then converted to acrylic ester-terminated prepolymers, preferably by acylation of the alcohol terminus with acryloyl chloride via a Schotten-Baumann-like technique, i.e., reaction of acyl halides with alcohols. The acrylic ester-terminated prepolymers may also be synthesized in a number of other ways, including but not limited to, reaction of carboxylic acids (i.e., acrylic or methacrylic acid) with alcohols, reaction of carboxylic acid esters (i.e., methyl acrylate or methyl methacrylate) with alcohols by transesterification, and reaction of isocyanatoalkyl acrylates (i.e., isocyanatoethyl methacrylate) with alcohols. The liquid acrylic-terminated prepolymer is cured, preferably by the addition of benzoyl peroxide or azobisisobutyronitrile, to a more solid structure. Thus, for an implant utilizing these crosslinkable polymers, the catalyst is added to the liquid acrylic-terminated prepolymer immediately prior to injection into the body. Once inside the body, the crosslinking reaction will proceed until sufficient molecular weight has been obtained to cause the polymer to solidify. The liquid prepolymer, when injected, will flow into the cavity or space in which it is placed and assume that shape when it solidifies. For drug delivery utilizing this system, biologically active agents are added to the liquid polymer systems in the uncatalyzed state. In both the thermoplastic and the thermosetting systems, the advantages of liquid application are achieved. For example, the polymer may be injected via syringe and needle into a body while it is in liquid form and then left in-situ to form a solid biodegradable implant structure. The need to form an incision is eliminated, and the implant will assume the shape of its cavity. Furthermore, a drug-delivery vehicle may be provided by adding a biologically active agent to the liquid prior to injection. Once the implant is formed, it will release the agent to the body and then biodegrade. The term "biologically active agent" means a drug or some other substance capable of producing an effect on a body. It is an object of the present invention, therefore, to provide a method and composition for producing biodegradable polymers. It is also an object of the present invention to provide such a polymer which may be useful in producing syringeable, in-situ forming, solid biodegradable implants. It is a further object of the present invention to provide such an implant which can be used in a controlled-release delivery system for biological agents. It is a further object of the present invention to provide implants having a range of properties from soft and elastomeric to hard and rigid, so as to be usable with both soft and hard tissue. BRIEF DESCRIPTION OF THE FIGURES AND TABLES FIG. 1 illustrates the synthesis of acrylate-terminated prepolymers and subsequent crosslinking by free-radical initiators; FIG. 2 illustrates structures for the random copolymer of ε-caprolactone and L-lactide initiated with a diol; FIG. 3 illustrates the bifunctional PLC prepolymers synthesized; FIG. 4 illustrates the acrylic ester terminated prepolymers synthesized; and FIG. 5A through FIG. 5E illustrate the curing studies. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to biodegradable, in-situ forming implants and methods for producing the same. The present invention also relates to a liquid biodegradable polymeric delivery system that can be injected into a body where it forms a solid and releases a biologically active agent at a controlled rate. Two types of biodegradable polymeric systems are described: thermoplastic polymers dissolved in a biocompatible solvent and thermosetting polymers that are liquids without the use of solvents. A. Thermoplastic System A thermoplastic system is provided in which a solid, linear-chain, biodegradable polymer is dissolved in a biocompatible solvent to form a liquid, which can then be administered via a syringe and needle. Examples of biodegradable polymers which can be used in this application are polylactides, polyglycolides, polycaprolactones, polyanhydrides, polyamides, polyurethanes, polyesteramides, polyorthoesters, polydioxanones, polyacetals, polyketals, polycarbonates, polyorthocarbonates, polyphosphazenes, polyhydroxybutyrates, polyhydroxyvalerates, polyalkylene oxalates, polyalkylene succinates, poly(malic acid), poly(amino acids), polyvinylpyrrolidone, polyethylene glycol, polyhydroxycellulose, chitin, chitosan, and copolymers, terpolymers, or combinations or mixtures of the above materials. The preferred polymers are those which have a lower degree of crystallization and are more hydrophobic. These polymers and copolymers are more soluble in the biocompatible solvents than the highly crystalline polymers such as polyglycolide and chitin which also have a high degree of hydrogen-bonding. Preferred materials with the desired solubility parameters are the polyactides, polycaprolactones, and copolymers of these with glycolide in which there are more amorphous regions to enhance solubility. It is also preferred that the solvent for the biodegradable polymer be non-toxic, water miscible, and otherwise biocompatible. Solvents that are toxic should not be used to inject any material into a living body. The solvents must also be biocompatible so that they do not cause severe tissue irritation or necrosis at the site of implantation. Furthermore, the solvent should be water miscible so that it will diffuse quickly into the body fluids and allow water to permeate into the polymer solution and cause it to coagulate or solidify. Examples of such solvents include N-methyl-2-pyrrolidone, 2-pyrrolidone, ethanol, propylene glycol, acetone, methyl acetate, ethyl acetate, methyl ethyl ketone, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, caprolactam, decylmethylsulfoxide, oleic acid, and 1-dodecylazacycloheptan-2-one. The preferred solvents are N-methyl-2-pyrrolidone, 2-pyrrolidone, dimethyl sulfoxide, and acetone because of their solvating ability and their compatibility. The solubility of the biodegradable polymers in the various solvents will differ depending upon their crystallinity, their hydrophilicity, hydrogen-bonding, and molecular weight. Thus, not all of the biodegradable polymers will be soluble in the same solvent, but each polymer or copolymer should have its optimum solvent. Lower molecular-weight polymers will normally dissolve more readily in the solvents than high-molecular-weight polymers. As a result, the concentration of a polymer dissolved in the various solvents will differ depending upon type of polymer and its molecular weight. Conversely, the higher molecular-weight polymers will normally tend to coagulate or solidify faster than the very low-molecular-weight polymers. Moreover the higher molecular-weight polymers will tend to give higher solution viscosities than the low-molecular-weight materials. Thus for optimum injection efficiency, the molecular weight and the concentration of the polymer in the solvent have to be controlled. For example, low-molecular-weight polylactic acid formed by the condensation of lactic acid will dissolve in N-methyl-2-pyrrolidone(NMP) to give a 73% by weight solution which still flows easily through a 23-gauge syringe needle, whereas a higher molecular-weight poly(DL-lactide) (DL-PLA) formed by the additional polymerization of DL-lactide gives the same solution viscosity when dissolved in NMP at only 50% by weight. The higher molecular-weight polymer solution coagulates immediately when placed into water. The low-molecular-weight polymer solution, although more concentrated, tends to coagulate very slowly when placed into water. For polymers that tend to coagulate slowly, a solvent mixture can be used to increase the coagulation rate. Thus one liquid component of the mixture is a good solvent for the polymer, and the other component is a poorer solvent or a non-solvent. The two liquids are mixed at a ratio such that the polymer is still soluble but precipitates with the slightest increase in the amount of non-solvent, such as water in a physiological environment. By necessity, the solvent system must be miscible with both the polymer and water. An example of such a binary solvent system is the use of NMP and ethanol for low-molecular-weight DL-PLA. The addition of ethanol to the NMP/polymer solution increases its coagulation rate significantly. It has also been found that solutions containing very high concentrations of high-molecular-weight polymers sometimes coagulate or solidify slower than more dilute solutions. It is suspected that the high concentration of polymer impedes the diffusion of solvent from within the polymer matrix and consequently prevents the permeation of water into the matrix where it can precipitate the polymer chains. Thus, there is an optimum concentration at which the solvent can diffuse out of the polymer solution and water penetrates within to coagulate the polymer. In one envisioned use of the thermoplastic system, the polymer solution is placed in a syringe and injected through a needle into the body. Once in place, the solvent dissipates, the remaining polymer solidifies, and a solid structure is formed. The implant will adhere to its surrounding tissue or bone by mechanical forces and can assume the shape of its surrounding cavity. Thus, the biodegradable polymer solution can be injected subdermally like collagen to build up tissue or to fill in defects. It can also be injected into wounds including burn wounds to prevent the formation of deep scars. Unlike collagen, the degradation time of the implant can be varied from a few weeks to years depending upon the polymer selected and its molecular weight. The injectable polymer solution can also be used to mend bone defects or to provide a continuous matrix when other solid biodegradable implants such as hydroxyapatite plugs are inserted into bone gaps. The injectable system can also be used to adhere tissue to tissue or other implants to tissue by virtue of its mechanical bonding or encapsulation of tissue and prosthetic devices. Another envisioned use of the thermoplastic system is to provide a drug-delivery system. In this use, a bioactive agent is added to the polymer solution prior to injection, and then the polymer/solvent/agent mixture is injected into the body. In some cases, the drug will also be soluble in the solvent, and a homogenous solution of polymer and drug will be available for injection. In other cases, the drug will not be soluble in the solvent, and a suspension or dispersion of the drug in the polymer solution will result. This suspension or dispersion can also be injected into the body. In either case, the solvent will dissipate and the polymer will solidify and entrap or encase the drug within the solid matrix. The release of drug from these solid implants will follow the same general rules for release of a drug from a monolithic polymeric device. The release of drug can be affected by the size and shape of the implant, the loading of drug within the implant, the permeability factors involving the drug and the particular polymer, and the degradation of the polymer. Depending upon the bioactive agent selected for delivery, the above parameters can be adjusted by one skilled in the art of drug delivery to give the desired rate and duration of release. The term drug or bioactive (biologically active) agent as used herein includes without limitation physiologically or pharmacologically active substances that act locally or systemically in the body. Representative drugs and biologically active agents to be used with the syringeable, in-situ forming solid implant systems include, without limitation, peptide drugs, protein drugs, desensitizing agents, antigens, vaccines, anti-infectives, antibiotics, antimicrobials, antiallergenics, steroidal anti-inflammatory agents, decongestants, miotics, anticholinergios, sympathomimetics, sedatives, hypnotics, psychic energizers, tranquilizers, androgenic steroids, estrogens, progestational agents, humoral agents, prostaglandins, analgesics, antispasmodics, antimalarials, antihistamines, cardioactive agents, non-steroidal anti-inflammatory agents, antiparkinsonian agents, antihypertensive agents, β-adrenergic blocking agents, nutritional agents, and the benzophenanthridine alkaloids. To those skilled in the art, other drugs or biologically active agents that can be released in an aqueous environment can be utilized in the described injectable delivery system. Also, various forms of the drugs or biologically active agents may be used. These include without limitation forms such as uncharged molecules, molecular complexes, salts, ethers, esters, amides, etc., which are biologically activated when injected into the body. The amount of drug or biologically active agent incorporated into the injectable, in-situ, solid forming implant depends upon the desired release profile, the concentration of drug required for a biological effect, and the length of time that the drug has to be released for treatment. There is no critical upper limit on the amount of drug incorporated into the polymer solution except for that of an acceptable solution or dispersion viscosity for injection through a syringe needle. The lower limit of drug incorporated into the delivery system is dependent simply upon the activity of the drug and the length of time needed for treatment. In all cases, the solid implant formed within the injectable polymer solution will slowly biodegrade within the body and allow natural tissue to grow and replace the impact as it disappears. Thus, when the material is injected into a soft-tissue defect, it will fill that defect and provide a scaffold for natural collagen tissue to grow. This collagen tissue will gradually replace the biodegradable polymer. With hard tissue such as bone, the biodegradable polymer will support the growth of new bone cells which will also gradually replace the degrading polymer. For drug-delivery systems, the solid implant formed from the injectable system will release the drug contained within its matrix at a controlled rate until the drug is depleted. With certain drugs, the polymer will degrade after the drug has been completely released. With other drugs such as peptides or proteins, the drug will be completely released only after the polymer has degraded to a point where the non-diffusing drug has been exposed to the body fluids. B. Thermosetting System The injectable, in-situ forming biodegradable implants can also be produced by crosslinking appropriately functionalized biodegradable polymers. The thermosetting system comprises reactive, liquid, oligomeric polymers which cure in place to form solids, usually with the addition of a curing catalyst. Although any of the biodegradable polymers previously described for the thermoplastic system can be used, the limiting criteria is that low-molecular-weight oligomers of these polymers or copolymers must be liquids and they must have functional groups on the ends of the prepolymer which can be reacted with acryloyl chloride to produce acrylic ester capped prepolymers. The preferred biodegradable system is that produced from poly (DL-lactide-co-caprolactone), or "DL-PLC". Low-molecular-weight polymers or oligomers produced from these materials are flowable liquids at room temperature. Hydroxy-terminated PLC prepolymers may be synthesized via copolymerization of DL-lactide or L-lactide and ε-caprolactone with a multifunctional polyol initiator and a catalyst. Catalysts useful for the preparation of these prepolymers are preferably basic or neutral ester-interchange (transesterification) catalysts. Metallic esters of carboxylic acids containing up to 18 carbon atoms such as formic, acetic, lauric, stearic, and benzoic are normally used as such catalysts. Stannous octoate and stannous chloride are the preferred catalysts, both for reasons of FDA compliance and performance. If a bifunctional polyester is desired, a bifunctional chain initiator such as ethylene glycol is employed. A trifunctional initiator such as trimethylolpropane produces a trifunctional polymer, etc. The amount of chain initiator used determines the resultant molecular weight of the polymer or copolymer. At high concentrations of chain initiator, the assumption is made that one bifunctional initiator molecule initiates only one polymer chain. On the other hand, when the concentration of bifunctional initiator is very low, each initiator molecule can initiate two polymer chains. In any case, the polymer chains are terminated by hydroxyl groups, as seen in FIG. 1. In this example, the assumption has been made that only one polymer chain is initiated per bifunctional initiator molecule. This assumption allows the calculation of a theoretical molecular weight for the prepolymers. A list of the bifunctional PLC prepolymers that were synthesized is given in Table 1. Appropriate amounts of DL-lactide, ε-caprolactone, and ethylene glycol were combined in a flask under nitrogen and then heated in an oil bath at 155° C. to melt and mix the monomers. The copolymerizations were then catalyzed by the addition of 0.03 to 0.05 wt % SnCl 2 . The reaction was allowed to proceed overnight. The hydroxyl numbers of the prepolymers were determined by standard titration procedure. The Gardner-Holdt viscosities of the liquid prepolymers were also determined using the procedures outlined in ASTM D 1545. The highest molecular-weight prepolymer (MW=5000) was a solid at room temperature; therefore, its Gardner-Holdt viscosity could not be determined. The diol prepolymers were converted to acrylic-ester-capped prepolymers via a reaction with acryloyl chloride under Schotten-Baumann-like conditions, as seen in FIG. 2 and summarized in Table 2. Other methods of converting the diol prepolymers to acrylic-ester-capped prepolymers may also be employed. Both THF and dichloromethane were evaluated as solvents in the acylation reactions. Several problems were encountered when THF was used as the solvent. The triethylamine hydrochloride formed as a by-product in the reaction was so finely divided that it could not be efficiently removed from the reaction mixture by filtration. Triethylamine hydrochloride (Et 3 N.HCl) has been reported to cause polymerization of acrylic species (U.S. Pat. No. 4,405,798). In several instances, where attempts to remove all of the Et 3 N.HCl failed, the acrylic-ester-capped prepolymers gelled prematurely. Thus, to effectively remove all of the Et 3 N.HCl, it was necessary to extract the prepolymers with water. For reactions carried out in THF, it is preferred that one first evaporate the THF in vacuo, redissolve the oil in CH 2 Cl 2 , filter out the Et 3 N.HCl, and then extract the CH 2 Cl 2 layer with water. Stable emulsions were sometimes encountered during extraction. The acylations were later carried out in CH 2 Cl 2 instead of THF. The filtration of Et 3 N.HCl from the reaction mixture was found to be much easier using this solvent, and the organic fraction could be extracted directly with water after filtration. Both diol and acrylic prepolymers were examined by IR and 1 H NMR spectroscopy. The salient feature of the IR spectra of diol prepolymers is a prominent O--H stretch centered at approximately 3510 cm -1 . Upon acylation, the intensity of the O--H stretch decreases markedly, and new absorbances at approximately 1640 cm -1 appear. These new absorbances are attributed to the C--C stretch associated with acrylic groups. Likewise, the presences of acrylic ester groups is apparent in the 1 H NMR spectra, the characteristic resonances for the vinyl protons falling in the range of 5.9 to 6.6 ppm. The acrylic prepolymers and diol prepolymers were then cured, as summarized in Table 3. The general procedure for the curing of the prepolymers is now described: to 5.0 g of acrylic prepolymer contained in a small beaker was added a solution of benzoyl peroxide (BP) in approximately 1 mL of CH 2 Cl 2 . In some cases, fillers or additional acrylic monomers were added to the prepolymers prior to the introduction of the BP solution. The mixtures were stirred thoroughly and then poured into small petri dishes. The dishes were placed in a preheated vacuum oven for curing. Some of the samples were cured in air and not in vacuo, and these samples are so indicated in Table 3. This thermosetting system may be used wherever a biodegradable implant is desired. For example, because the prepolymer remains a liquid for a short time after addition of the curing agent, the liquid prepolymer/curing agent mixture may be placed into a syringe and injected into a body. The mixture then solidifies in-situ, thereby providing an implant without an incision. Furthermore, a drug-delivery system may be provided by adding a biologically active agent to the prepolymer prior to injection. Once in-situ, the system will cure to a solid; eventually, it will biodegrade, and the agent will be gradually released. DETAILED DESCRIPTION OF EXAMPLES The following examples are set forth as representative of the present invention. These examples are not to be construed as limiting the scope of the invention as these and other equivalent embodiments will be apparent in view of the present disclosure, figures, and accompanying claims. EXAMPLE 1 Poly(DL-lactic acid) was prepared by the sample polycondensation of lactic acid. No catalysts were used, and the reaction times were varied to produce polymers with different theoretical molecular weights. These polymers were designated as DL-PLA oligomers. A quantity of the solid oligomer was dissolved in NMP to give a 68:32 ratio of polymer to solvent. Sanguinarine chloride(SaCl), a benzophenanthridine alkaloid with antimicrobial activity especially toward periodontal pathogens, was added to the polymer solution to give a 2% by weight dispersion of the drug in the total mixture. The dispersion of drug and polymer solution was then injected into a dialysis tube (diameter of 11.5 mm) with a sterile disposable syringe without a needle. Each end of the 6-in. length of dialysis tubing was tied with a knot to prevent loss of the drug/polymer mass, and the tube with the injected material was placed in a pH 7 Sorenson's buffer receiving fluid maintained at 37° C. Upon immersion in the receiving fluid, the drug/polymer mass coagulated into a solid mass, and the drug began to be released from the polymer as indicated by an orange-red color in the receiving fluid. The quantity of solution injected into the dialysis tube was about 250 μL or about 100 mg of solids. The dialysis tubing was selected to have a molecular-weight cutoff of about of about 3,500. With this molecular-weight cutoff, the SaCl released from the polymer could easily diffuse through the walls of the tubing, but any solid polymer would be retained. The dialysis tubing containing the drug/polymer matrix was removed frequently and placed in a bottle of fresh receiving fluid. The old receiving fluid containing the released drug was then acidified to a pH of 2.76 to convert all released drug to the iminium ion form of the drug, and the concentration of drug was determined by measuring the ultraviolet absorption (UV) at a wavelength of 237 nm. The cumulative mass of drug released and the cumulative fraction were then calculated and plotted as a function of time. Approximately 60% of the drug was released in the first day, 72% after 2 days, 85% after 5 days, 90% after 9 days, and 97% after 14 days. EXAMPLE 2 Ethoxydihydrosanguinarine(SaEt), the ethanol ester of sanguinarine, was added to the same DL-PLA oligomer/NMP solution described in Example 1. SaEt dissolved in the polymer solution to give a homogenous solution of drug and polymer. Approximately 250 μL of the solution was added to receiving fluid and the release of drug measured as described in Example 1. The release of SaEt was slower than that for SaCl as expected because of its lower water solubility. After the first day, approximately 45% was released, 52% after 2 days, 60% after 5 days, 70% after 9 days, and 80% after 14 days. EXAMPLE 3 Poly(DL-lactide) with an inherent viscosity of 0.08 dL/g and a theoretical molecular weight of 2,000 was prepared by the ring-opening polymerization of DL-lactide using lauryl alcohol as the initiator and stannous chloride as the catalyst. This polymer was then dissolved in NMP to give a 40% by weight polymer solution. SaCl was dispersed in the solution of this polymer in NMP to give a 1.5% by weight dispersion of the drug in the solution and the release rate determined as described in Example 1. The release rate of the drug from this higher molecular-weight polymer was slower than from the DL-PLA oligomer. After the first day, approximately 32% was released, 40% after 2 days, 45% after 5 days, and 50% after 15 days. EXAMPLE 4 SaEt was added to the same polymer solution of DL-PLA in NMP as described in Example 3. A homogenous solution with the drug at 1.5% by weight was obtained. The release of drug from this solution determined using the same procedure described in Example 1 gave a much slower release of SaEt than from the DL-PLA oligomer. After the first day approximately 8% was released, 14% after 2 days, 20% after 5 days, 23% after 9 days, and 28% after 14 days. EXAMPLE 5 The effect of drug loading on the release of drug from the polymer solutions were demonstrated by adding SaCl to a 40% by weight of DL-PLA oligomer in NMP. The drug was dispersed in the polymer solution to give 2, 7 and 14% by weight dispersions. The release of drug from these formulations using the same procedure as described in Example 1 showed that the higher drug loadings gave a lower fractional rate of release as normally obtained for matrix delivery systems with diffusional release. The 2%-loaded formulation gave 65% release after 1 day, 75% after 2 days, and 88% after 5 days; the 7%-loaded formulation gave 48% release after 1 day, 52% after 2 days, and 58% after 5 days, and the 14%-loaded formulation gave 38% release after 1 day, 43% after 2 days, and 49% after 5 days. EXAMPLE 6 Poly(DL-lactide-co-glycolide) was prepared by the ring-opening polymerization of a mixture of DL-lactide and glycolide using lauryl alcohol as the initiator and stannous chloride as the catalyst. The proportions of the two monomers were adjusted so that the final copolymer(DL-PLG) had a 50:50 ratio of the two monomers as determined by nuclear magnetic resonance spectrophotometry. The initiator was also adjusted to give a copolymer with a theoretical molecular weight of 1500 daltons. The copolymer was dissolved in NMP to give a 70% by weight polymer solution. SaCl was added to this solution to give a 2% by weight dispersion of the drug in the polymer solution. The release of drug from this formulation was determined using the same procedure described in Example 1. A much lower release rate was obtained from the copolymer than from the DL-PLA oligomer or DL-PLA 2000 molecular weight materials. After 2 days approximately 7% of the drug was released, 10% after 5 days, 12% after 7 days, and 16% after 14 days. EXAMPLE 7 SaEt was added to the same solution of DL-PLG in NMP as described in Example 6 to give a 2% by weight solution of the drug. The release of drug from this formulation was determined by the same procedure as described previously. The release rate of SaEt from this formulation was identical to that for SaCl described in Example 6. EXAMPLE 8 Tetracycline as the free base (TCB) was added to the same solution of DL-PLG in NMP as described in Example 6. The drug dissolved completely in the polymer solution to give a 2.4% by weight solution of the drug. The release of the drug from this formulation was determined by a similar procedure to that described in Example 1 except the receiving fluid was not acidified to a pH of 2.76 and the concentration of TCB was determined by UV absorption at the wavelength appropriate for the drug. The release of TCB from this formulation was more linear and at a much higher rate than that for SaCl or SaEt from the same copolymer. After 1 day approximately 44% of the drug was released, 54% after 2 days, 68% after 5 days, 73% after 6 days, 80% after 7 days, 87% after 9 days, 96% after 12 days, and 100% after 14 days. EXAMPLE 9 Tetracycline as the hydrochloride salt (TCH) was added to the same solution of DL-PLG in NMP as described in Example 6. The salt form of the drug also dissolved completely in the polymer solution. The release of drug from this formulation was determined as described in Example 8 and found to be similar to that for the free base except for a slightly lower rate. After 1 day approximately 32% of the drug was released, 40% after 2 days, 57% after 5 days, 64% after 6 days, 75% after 7 days, 82% after 9 days, 92% after 12 days, and 100% after 14 days. EXAMPLE 10 DL-PLA with an inherent viscosity of 0.26 dL/g and a theoretical molecular weight of approximately 10,000 daltons was prepared by the ring-opening polymerization of DL-lactide using lauryl alcohol as the initiator and stannous chloride as the catalyst. The polymer was dissolved in NMP to give a 50% by weight polymer solution. A quantity of the polymer solution (100 μL) was injected subdermally into rabbits, and the tissue reaction was compared to that of a USP negative plastic. The test sites were evaluated for signs of local irritation, in accordance with the Draize method, immediately after injection, at 1 and 6 hours post injection, and once daily thereafter until scheduled sacrifice at 7, 14 or 21 days. The reaction at the test sites was equivalent to that at the control USP negative plastic. The polymer solution (100 μL) was also administered subgingivally into sites created by dental extractions in Beagle dogs. Control sites were flushed with saline solution. The dogs were examined daily for signs of mortality, pharmacotoxic effects, body weights, and local gingival irritation. The animals were sacrificed at 15 and 21 days. No distinct differences were noted between the control and test sites. EXAMPLE 11 DL-PLA with an inherent viscosity of 0126 dL/g and a molecular weight of about 10,000 was dissolved in NMP to give a 50% by weight polymer solution. SaCl was added to the polymer solution to give a 2.4% by weight dispersion. This material was loaded into a 1-cc disposable syringe fitted with a 23-gauge blunted-end syringe needle, and the material was inserted into the periodontal pocket of a greyhound dog. The material flowed easily out of the narrow syringe tip. The polymer precipitated or coagulated into a film or solid mass when it contacted the saliva and fluid within the pocket. The dog was observed over a time of 2 weeks during which the mass of material remained within the pocket, adhering to tissue surrounding the pocket, and slowly changing color from a light orange to a pale white. The crevicular fluid from the pocket containing the implant was sampled during this 2-week period using Periostrips which are small strips of paper that are placed at the entrance to the periodontal pocket to wick up small quantities of the crevicular fluid within the pocket. The volume of fluid collected is determined using a Periotron which measures the changes in conductance of the paper strip. The Periotron is calibrated before use with a known volume of serum. The paper strip containing the collected fluid is then extracted with a solution of 0.5% by volume of hydrochloric acid in methanol and injected into a liquid chromatograph where the quantity of drug is determined by reference to a known concentration of the same compound. The quantity of SaCl extracted from the paper strip is divided by the quantity of crevicular fluid collected to calculate the concentration of drug in the fluid. With this technique, the concentration of SaCl within the crevicular fluid from the periodontal pocket with the polymeric delivery system was determined to be almost constant during the 2 weeks of observation. The SaCl concentration in the crevicular fluid was 63.2 μg/mL after 3 days, 80.2 μg/mL after 7 days, 67.8 μg/mL after 10 days, and 70.5 μg/mL after 14 days. EXAMPLE 12 An illustrative method for the synthesis of an acrylate terminated prepolymer is described. To an oven-dried, 500-mL, three-necked, round-bottom flask fitted with an addition funnel, gas inlet adapter, mechanical stirrer assembly, and rubber septum was added, under nitrogen, 100.0 g of difunctional hydroxy-terminated prepolymer and 200 mL of freshly distilled THF (from CaH 2 ). The flask was cooled in an ice bath, and 24 mL of dry triethylamine (0.95 equiv/equiv OH) was added via a syringe. The addition funnel was charged with 15.4 g of acryloyl chloride (0.95 equiv/equiv OH) in 15 mL of THF, and the solution was added dropwise to the stirred reaction mixture over 1 hour. The mixture was stirred overnight and allowed to reach room temperature. The precipitated triethylamine hydrochloride was removed by filtration, and the filtrate was evaporated in vacuo, affording a pale yellow oil, which was the acrylate-terminated prepolymer. The acylations employing CH 2 Cl 2 as solvent were conducted in a similar manner. However, the reaction times at 0° C. were shortened to 1 hour, whereupon the reaction mixtures were allowed to reach room temperature over 1 hour. Et 3 N 1 HCl was filtered out, additional CH 2 Cl 2 (approximately 800 mL) was added to the filtrate, and the filtrate was extracted several times with 250 mL portions of water. The organic layer was dried over MgSO 4 /Na 2 SO 4 , filtered, and reduced to an oil in vacuo. The bottles of acrylic prepolymers were wrapped in foil and stored in a refrigerator to safeguard against premature crosslinking.

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CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional application of co-pending prior U.S. patent application Ser. No. 10/186,941 filed on Jun. 28, 2002 entitled “METHOD AND APPARATUS FOR FLUID DELIVERY TO A BACKSIDE OF A SUBSTRATE”, which is herein incorporated by reference in its entirety for all purposes. BACKGROUND OF THE INVENTION [0002] The present invention relates generally to semiconductor fabrication and, more particularly, to a method and apparatus for reducing consumption of fluid delivered to a backside of a substrate during a cleaning operation. [0003] Cleaning chemistries for single wafer cleaning operations are formulated for specific applications and are designed so that a small amount of the chemistry applied to the surface of the wafer is sufficient for cleaning the surface of the wafer. That is, a thin film of the fluid supplied to the surface of the wafer produces the desired cleaning effects. Because of the high costs for the purchase and the disposal of the cleaning chemistries, it is desired to only use the amount of chemistry that is necessary for effective cleaning. [0004] Applying a thin film of the cleaning chemistry to a top surface of a semiconductor substrate is easily accomplished as gravity is working to assist the process. A small amount of fluid can be puddled on a top surface of the substrate and the substrate can be rotated around its axis to spread the fluid over the surface of the substrate without spinning the fluid off of the wafer surface. The speed of the rotation can be used to control the thickness of the fluid layer. However, the cleaning chemistry can not be applied to the backside of the wafer in this manner as the fluid will be lost. FIG. 1 is a schematic diagram of a wafer having cleaning chemistries applied to a top and a backside of the wafer. Wafer 100 has a thin film applied to a top surface of the wafer by top nozzle 104 a . However, bottom surface 106 can not retain the fluid from bottom nozzle 104 b , where as much as 95% of the fluid delivered to bottom surface 106 can be lost. Thus, conventional spray-on techniques are not effective for low-volume chemistry cleaning of the wafer backside. [0005] One attempt to minimize the fluid loss associated with cleaning the backside of the wafer is to clean the top side of the wafer and then flip the wafer over to clean the other side. However, the throughput for the cleaning process is cut in half since the cleaning is performed sequentially. Accordingly, this alternative is not a viable one. Another attempt to address the shortcomings of the prior art is to provide a reservoir containing the cleaning chemistry and place the backside of the wafer in contact with a meniscus formed by the cleaning chemistry. FIG. 2 is schematic diagram of a wafer coming into contact with a meniscus of a cleaning solution in a reservoir. Bottom surface 106 of wafer 100 is brought into contact with meniscus 108 . Meniscus 108 is formed when the cleaning chemistry is filled to the top of reservoir 110 . However, a shortcoming with the use of a reservoir is due to each of the cleaning solutions having different surface tensions. Thus, the meniscus height can be different for each of the cleaning chemistries. Consequently, the distance for the wafer to be brought into contact with the cleaning chemistry will change with the different cleaning chemistries. This configuration is also difficult to implement mechanically. Additionally, the contents of reservoir 110 will have to be changed over time as the cleaning chemistry becomes dirty, which negatively impacts throughput and control of contaminants. [0006] In view of the foregoing, there is a need for a method and apparatus for reducing the volume of cleaning chemistry applied to the backside of a wafer in a single-wafer cleaning tool in a manner that does not negatively impact the throughput or defect rate. SUMMARY OF THE INVENTION [0007] Broadly speaking, the present invention fills this need by providing a nozzle and delivery system for applying a minimal amount of fluid to the backside of a semiconductor substrate. It should be appreciated that the present invention can be implemented in numerous ways, including as an apparatus, a system, a device, or a method. Several inventive embodiments of the present invention are described below. [0008] In accordance with one aspect of the present invention, a nozzle is provided. The nozzle includes an inner cylindrical tube having a top opening and a bottom opening. An upper cap overlying a top portion of the inner cylindrical tube is included. The upper cap is moveably disposed over the inner cylindrical tube. The upper cap includes a top with at least one hole defined therein. The top includes a sidewall extending therefrom. [0009] In accordance with another aspect of the invention, a fluid delivery system for cleaning a backside of a semiconductor substrate is included. The fluid delivery system includes a shaft configured to rotate about an axis of the shaft. An arm having a first end and a second end is included. The first end is affixed to the shaft and is in communication with a fluid source. A cap moveably disposed over the second end of the arm is included. The cap has a top with at least one hole defined therein. The top includes a sidewall extending therefrom. The sidewall extends over a portion of the second end of the arm. [0010] In accordance with yet another aspect of the invention, a method for reducing an amount of a cleaning chemistry applied to a backside of a wafer during a cleaning operation is provided. The method initiates with positioning a nozzle having a moveable top under a backside of a wafer to be cleaned. Then, a fluid flow occurs through the moveable top to raise the moveable top into close proximity with the backside of the wafer. Next, a fluid barrier is created between a top surface of the moveable top and a backside of the wafer while the fluid flows through the moveable top. Then, the backside of the wafer is cleaned by the fluid barrier. [0011] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS [0012] The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the principles of the invention. [0013] [0013]FIG. 1 is a schematic diagram of a wafer having cleaning chemistries applied to a top and a backside of the wafer. [0014] [0014]FIG. 2 is schematic diagram of a wafer coming into contact with a meniscus of a cleaning solution in a reservoir. [0015] [0015]FIG. 3 is a simplified schematic diagram of a chemical delivery system in accordance with one embodiment of the invention. [0016] [0016]FIG. 4 is a cross-sectional schematic diagram of the nozzle of FIG. 3 in an activated state in accordance with one embodiment of the invention. [0017] [0017]FIG. 5A is a cross-sectional view of a schematic diagram of a sealed nozzle in a relaxed state in accordance with one embodiment of the invention. [0018] [0018]FIG. 5B is a cross-sectional view of a schematic diagram of the nozzle of the FIG. 5A in an active state. [0019] [0019]FIG. 6A is a cross-sectional view of a schematic diagram of a nozzle having a bellows seal in accordance with one embodiment of the invention. [0020] [0020]FIG. 6B is a cross-sectional view of a schematic diagram of a nozzle having a continuous wall with a thinned section in an extended position in accordance with another embodiment of the invention. [0021] [0021]FIG. 6C is a cross-sectional view of a schematic diagram of the nozzle of FIG. 6B having a continuous wall with a thinned section in a retracted position. [0022] [0022]FIG. 7A is a top view of a nozzle for delivering a fluid to the backside of a wafer in accordance with one embodiment of the invention. [0023] [0023]FIG. 7B is a top view of an alternative orifice arrangement to FIG. 7A. [0024] [0024]FIG. 7C is a top view of another alternative nozzle configuration in accordance with one embodiment of the invention. [0025] [0025]FIG. 8 is a flowchart of the method operations reducing an amount of a cleaning chemistry applied to a backside of a wafer during a cleaning operation in accordance with one embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION [0026] Several exemplary embodiments of the invention will now be described in detail with reference to the accompanying drawings. FIGS. 1 and 2 are discussed above in the “Background of the Invention” section. As used herein, the term about refers to a reasonable approximation of the specific range provided. [0027] [0027]FIG. 3 is a simplified schematic diagram of a chemical delivery system in accordance with one embodiment of the invention. Nozzle 126 is positioned under the backside of wafer 120 . Nozzle 126 is disposed over an end of supply arm 124 . In one embodiment, supply arm 124 is a cylindrical tube compatible with the cleaning chemicals used to clean the backside of wafer 120 . It should be appreciated that supply arm 124 acts as an end effector. Another end of supply arm 124 is affixed to shaft 122 . In one embodiment, shaft 122 rotates about its axis so that nozzle 126 can move in a radial direction under the backside of wafer 120 . Fluid delivery source 128 is in communication with supply arm 124 . One skilled in the art will appreciate that fluid delivery source 128 can include a pump for delivering a cleaning chemistry to the backside of wafer 120 through nozzle 126 , in one embodiment. [0028] It should be appreciated that wafer 120 can be cleaned after a semiconductor fabrication process, such as chemical mechanical planarization (CMP), etch operations, etc. Examples of single wafer cleaning chemistries commonly used for post-etch cleaning include commercially available proprietary chemicals, such as EKC 640, EKC 6800 and Ashland NE89. Commercially available non-proprietary chemicals used for post chemical mechanical planarization cleaning are generally known and include SC-1 (NH 4 OH/H 2 O 2 mixture), SC-2 (HCl/H 2 O 2 mixture), dilute HF or ozonated DIW (H 2 O/O 3 ). [0029] Still referring to FIG. 3, top nozzle 121 can add a cleaning agent to the top surface of wafer 120 simultaneously while cleaning the backside of the wafer. Here, the same cleaning chemistry or a different cleaning chemistry can be added to each side of wafer 120 . For example, where a post-etch cleaning operation is being performed on the top surface of wafer 120 , there may be photoresist pieces deposited on the backside of the wafer which carried over from a lithography step. Accordingly, different chemistries can be applied to the top surface and the backside of wafer 120 simultaneously due to the efficiency enabled through the nozzle described herein. Thus, the system throughput can be increased by performing separate cleaning operation on the two sides of wafer 120 simultaneously. [0030] [0030]FIG. 4 is a cross-sectional schematic diagram of the nozzle of FIG. 3 in an activated state in accordance with one embodiment of the invention. Nozzle 126 is disposed over a top portion of supply arm 124 . A degree of travel of nozzle 126 in an up and down direction is limited in one embodiment. That is, shoulder 134 of nozzle 126 is configured so as to be unable to move past protrusion 136 of supply arm 124 . Here, supply arm 124 is fixed and protrusion 136 acts as a travel limiter for the moveable nozzle. Nozzle 126 moves to a raised position as fluid is delivered through supply arm 124 . Nozzle 126 includes orifice 132 which is defined through a top surface of the nozzle. Orifice 132 is configured to provide some back-pressure, thereby causing nozzle 126 to raise while fluid is escaping through the orifice. [0031] Still referring to FIG. 4, nozzle 126 continues to rise as fluid is provided from supply arm 124 . Eventually, a thin film, i.e., fluid barrier, is defined between wafer 120 and a top surface of nozzle 126 . The pressure exerted by nozzle 126 on the thin film, which has a thickness 130 defined between the backside of wafer 120 and a top surface of nozzle 126 , becomes insufficient to further compress the thin film. In one embodiment, the thin film is composed of the cleaning chemistries mentioned above. It should be appreciated that the thin film acts as a fluid barrier and a fluid bearing as wafer 120 rotates and nozzle 126 is radially swept across the backside of the rotating wafer. Top surface of nozzle 126 is substantially flat and self-aligns to the backside of the wafer. The self alignment is due to the sliding mechanism of nozzle 126 over supply arm 124 caused by the flow rate and pressure at which the cleaning chemistry is delivered. It should be appreciated that the top surface of nozzle 126 does not physically contact the backside of the wafer 120 . That is, the top surface of nozzle 126 is in contact with the backside of wafer 120 through the fluid barrier interface. Opposing surfaces of the fluid barrier physically contacts the backside of wafer 120 and a top surface of nozzle 126 . Thus, should wafer 120 have a wobble or run-out as it rotates, nozzle 126 will accommodate the wobble and run out and not come in contact with the backside of the wafer. In one embodiment, the thin film between the backside of wafer 120 and a top surface of nozzle 126 has a thickness of between about 0.1 millimeter (mm) and about 2 mm. [0032] It should be appreciated that a portion of the fluid delivered to nozzle 126 of FIG. 4 can escape through gap 138 between nozzle 126 and supply arm 124 . Alternatively, the nozzle 126 and supply arm 124 can be machined so that gap 138 is minimized, i.e., the tolerance between the nozzle inner diameter at shoulder 134 and the supply arm outer diameter does not allow for the fluid to escape. The configuration of nozzle 126 allows for a lower flow rate to be applied because the losses of the fluid applied to the backside of the wafer are reduced. In one embodiment, a flow rate of between about 25 milliliters (ml) and about 50 ml is sufficient to supply the necessary backpressure to lift nozzle 126 and to create a fluid barrier Of course, the flow rate can change depending on the application, cleaning chemistry, pump, etc. Thus, the above flow rate is meant to be exemplary and not restrictive. [0033] [0033]FIG. 5A is a cross-sectional view of a schematic diagram of a sealed nozzle in a relaxed state in accordance with one embodiment of the invention. Nozzle 126 is disposed over supply arm 124 . As there is no fluid being delivered from supply arm 124 , nozzle 126 is in a relaxed position. Thus, gap 142 between the backside of wafer 120 and a top surface of nozzle 126 is larger here. O-ring 140 acts as a seal between nozzle 126 and supply arm 124 . It should be appreciated that the composition of O-ring 140 can be any material suitable for allowing the up and down motion of nozzle 126 and the material is chemically compatible with the cleaning chemistries. Similarly, the composition of nozzle 126 and supply tube 124 can be any material suitable for the cleaning process that is compatible with the cleaning chemicals. [0034] [0034]FIG. 5B is a cross-sectional view of a schematic diagram of the nozzle of the FIG. 5A in an active state. Here, a fluid flow through supply arm 124 provides the pressure to raise nozzle 126 while fluid escapes through orifice 132 . A fluid barrier is formed between the backside of wafer 120 and a top surface of nozzle 126 . The fluid barrier also acts as a fluid bearing, which in essence allows for the top surface of nozzle 126 to be in contact with the backside of wafer 120 through the fluid barrier interface. In one embodiment, the fluid is a cleaning chemistry. For example a post-etch or post CMP cleaning chemistry can be delivered to nozzle 126 through supply arm 124 for cleaning the backside of wafer 120 . O-ring 140 seals a gap between nozzle 126 and supply arm 124 , thereby forcing the fluid through orifice 132 without restricting the movement of nozzle 126 . In one embodiment, the flow rate of the cleaning chemistry from supply arm 124 is about less that 100 milliliters (ml)/minute. In a preferred embodiment, the flow rate is about less that 50 ml/minute. [0035] [0035]FIG. 6A is a cross-sectional view of a schematic diagram of a nozzle having a bellows seal in accordance with one embodiment of the invention. Nozzle 126 , which is disposed over an end of supply arm 124 , includes bellows seal 142 . As is known, bellows seal 142 contracts and expands as nozzle 126 moves from a relaxed state to an active state. It should be appreciated that there is no need for the protrusion and shoulders with reference to FIGS. 4, 5A and 5 B, since bellows seal 142 acts as a travel limiter. In one embodiment, top surface 144 of nozzle 126 provides a substantially flat surface where the fluid, i.e., cleaning chemistry, can reside as the nozzle moves radially across the wafer and as the wafer rotates. While some fluid will be lost, the losses are significantly reduced as compared with spray-on techniques of the prior art. In addition, the flow of fluid through orifice 132 is constantly replenishing any losses and maintains the fluid barrier which cleans the backside of the wafer. [0036] [0036]FIG. 6B is a cross-sectional view of a schematic diagram of a nozzle having a continuous wall with a thinned section in an extended position in accordance with another embodiment of the invention. Supply arm 147 is a continuous wall with thinned section 145 . As fluid flows through opening 132 of nozzle 126 , a back pressure forces the top portion of nozzle 126 to an extended state. Thinned section 145 acts as an extension point as it is flexible and the back pressure provides the necessary force to lift the top portion of nozzle 126 under a pressure or flow of fluid. In one embodiment, thinned section 145 has a thickness between about 0.01 mm and about 0.5 mm. Supply arm 147 can be fabricated from any suitable material such as plastic or metal that is compatible with the cleaning chemistries and is capable of being thinned while maintaining sufficient strength and pliability. [0037] [0037]FIG. 6C is a cross-sectional view of a schematic diagram of the nozzle of FIG. 6B having a continuous wall with a thinned section in a retracted position. Here, the flow of fluid causing the back pressure has been stopped and the top portion of nozzle 126 retracts. The retraction is due to the folding of thinned section 145 of supply arm 147 . In one embodiment, the range of travel between full extension and full retraction is less than 2 millimeters. [0038] [0038]FIG. 7A is a top view of a nozzle for delivering a fluid to the backside of a wafer in accordance with one embodiment of the invention. Orifice 132 is substantially centered on top surface 144 of cylindrically shaped nozzle 126 . Nozzle 126 can be referred to as a cap. It should be appreciated that orifice 132 has a suitable diameter for allowing enough back pressure to lift nozzle 126 while allowing a fluid flow out of the orifice to obtain a suitable fluid barrier. In one embodiment, the diameter of nozzle 126 is between about 5% and 30% of the diameter of the wafer being cleaned. In a preferred embodiment, the diameter of nozzle 126 is between about 25% of the diameter of the wafer being cleaned. In another embodiment, the diameter of the nozzle is configured to enable completion of the cleaning of the backside of the wafer within about 5 seconds, when the nozzle is moving radially across the wafer as the wafer is rotating. [0039] [0039]FIG. 7B is a top view of an alternative orifice arrangement to FIG. 7A. Here, a plurality of orifices 146 are distributed over top surface 144 of nozzle 126 . In one embodiment, orifices 146 have a diameter between about 0.5 millimeters (mm) and about 5 mm. The holes defined by orifices 146 , have a suitable diameter for allowing enough back pressure to lift nozzle 126 while allowing a fluid flow out of the orifice to obtain a suitable fluid barrier. It will be apparent to one skilled in the art that any suitably-shaped hole or orifice can be used here. [0040] [0040]FIG. 7C is a top view of another alternative nozzle configuration in accordance with one embodiment of the invention. Nozzle 152 is configured as an elongated cylinder having a plurality of orifices 132 . In one embodiment, length 150 of nozzle 152 is slightly large than the radius of the wafer being cleaned. One skilled in the art will appreciate that by defining the length of the nozzle longer than a radius of the wafer, the backside of the wafer can be cleaned in one rotation of the wafer. [0041] [0041]FIG. 8 is a flowchart of the method operations reducing an amount of a cleaning chemistry applied to a backside of a wafer during a cleaning operation in accordance with one embodiment of the invention. The method initiates with operation 154 where a nozzle having a moveable top is positioned under a backside of a wafer. A suitable nozzle is described with reference to FIGS. 3 - 7 C. The method then advances to operation 156 where a fluid flow through the moveable top moves the moveable top into close proximity with the backside of the wafer. The fluid flow causes a back pressure which in turn, lifts the moveable top towards the backside of the wafer. In one embodiment, the moveable top is limited in the amount of travel towards the backside of the wafer. In another embodiment, the moveable top slides along a fixed supply arm in a manner that allows the moveable top to self align to the backside of the wafer being cleaned. [0042] The method of FIG. 8 then proceeds to operation 158 where a fluid barrier is created between the top surface of the moveable top and the backside of the wafer. Here, the fluid flow through an orifice in a top surface of the moveable top causes the moveable top to trap a fluid barrier between the backside of the wafer and the top surface. The fluid barrier acts as a fluid bearing as the wafer and the nozzle move. In one embodiment, the fluid is a post etch or post CMP cleaning chemistry. The method then advances to operation 160 where the backside of the wafer is cleaned with the fluid barrier. Here, the fluid barrier cleans the backside of the wafer since the nozzle is in close proximity to the backside of the wafer and the fluid flow maintains the fluid barrier. For example, the nozzle can be attached to a supply arm as described with reference to FIG. 3. Due to the configuration of the nozzle, with reference to FIGS. 4 - 6 , the loss of the fluid is significantly reduced and the residence time of the fluid barrier can be controlled by the speed of the movement of the wafer and the nozzle. In one embodiment, where the surface area of the top surface of the nozzle is about 25% of the surface area of the backside of the wafer, the backside of the wafer is cleaned in about 5 seconds. [0043] In summary, the present invention provides a nozzle configured to apply a thin coating of fluid, i.e., fluid barrier, to the backside of a wafer. In one embodiment, the thin coating of fluid is a cleaning chemistry for a post-etch cleaning or a post CMP cleaning. The nozzle makes use of an outer cylinder having an orifice on a top surface slidably disposed over a fixed inner cylinder in one embodiment. The sliding mechanism allows the nozzle to self align to the backside of the wafer. The top surface allows a fluid barrier to be formed so that the cleaning chemistry has a long enough residence time on the wafer backside to clean the wafer backside. In one embodiment, a system configured to perform different cleaning operations simultaneously on a top surface of a wafer and a bottom surface of a wafer in an efficient manner is enabled by the nozzle configuration. Thus, the throughput of the system is enhanced by performing different cleaning operations on the top and bottom surfaces of the wafer at the same time. [0044] The invention has been described herein in terms of several exemplary embodiments. For example, representative shapes and sizes of the nozzle, i.e., cap, have been described herein, however any suitable shape and size nozzle can be used to apply the cleaning chemistry to the backside of the wafer. Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention. The embodiments and preferred features described above should be considered exemplary, with the invention being defined by the appended claims.

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of evaluating the characteristics of superconductors, a process for forming a superconductor film by using the method, and an apparatus for carrying out the process. 2. Description of the Related Art The recent research into and development of high temperature superconductors has included an application thereof to electronic elements such as semiconductor devices. The mechanism of this superconduction is not absolutely clear, however, and a method of evaluating the characteristics of superconductors has not been established. Particularly, in the case of a superconductor film formed by a chemical vapor deposition (CVD), a molecular beam epitaxy (MBE), sputtering, vapor deposition, or the like, the mass to be evaluated is so small that the available evaluation methods are limited in that an evaluation at a required precision is impossible, and this has raised a problem in the developing of a superconductor film having a good crystalline structure and applicable to electronic elements. Namely, in the conventional evaluation method, the ratio of the number of electrons contributing to a normal conduction to the number of electrons contributing to a superconduction in a superconductor is evaluated by measuring the magnetic susceptibility of the superconductor. The magnetic susceptibility can be measured at a high precision when the mass to be measured has a large volume, such as a bulk material produced by a sintering process or the like, but when the mass to be measured has a minute volume such as a film material, a required sensitivity cannot be obtained and the characteristics of a superconductor cannot be precisely evaluated. Because the superconductive property of a superconductor depends greatly not only upon the chemical composition thereof but also upon the process conditions during the forming thereof such as the forming temperature, it is necessary to evaluate the characteristics of a superconductor during the growth thereof and to feed back the evaluated results to the process conditions to thereby form a superconductor having a good characteristic. The conventional process and apparatus for forming a superconductor film, however, does not provide a method of evaluating the characteristics of a film during the forming thereof, and thus an effective feedback is not possible. SUMMARY OF THE INVENTION The object of the present invention is to provide a method of evaluating the characteristic of superconductors at a high precision even when the mass to be evaluated is small, a process for forming a superconductor film by using this evaluation method to evaluate the characteristic of a film during the forming thereof and control the process conditions based on the result of the evaluation, and an apparatus for carrying out this process. To achieve the object according to the present invention, there is provided a method of evaluating the characteristics of superconductors, comprising: irradiating light to a superconductor held at a predetermined temperature; detecting light transmitted through the superconductor and composing a spectrum of the transmitted light; and using the spectrum to calculate a ratio of the number of electrons contributing to a normal conduction to the number of electrons contributing to a superconduction in the superconductor, the ratio being effective at said predetermined temperature. The method according to the present invention measures the spectrum of light transmitted through a superconductor and evaluates, from variations of the light transmitted or transmittance, the ratio of the number of electrons contributing to a normal conduction (hereinafter referred to as "normal conduction electrons") to the number of electrons contributing to a superconduction (hereinafter referred to as "superconduction electrons"). The irradiation is conveniently effected with an infrared or extreme infrared ray. The measurement of these rays has been well established and is conventionally carried out to provide a precise evaluation of the characteristics of metal or semiconductor films, and therefore, is readily applicable to the evaluation of a minute quantity such as a superconductor film. The calculation according to the present invention preferably comprises: comparing an observed spectrum of the transmitted light with a theoretical spectrum defined by the following formula (1); and calculating the ratio by using the following formula (2). ##EQU1## where R: reflectance, n: real part of complex refractive index, k: imaginary part of complex refractive index, α: absorption coefficient, d: thickness of sample. ε=ε.sup.∞ +f.sub.n ε.sub.d +(1-f.sub.n)ε.sub.s ( 2) where ε: complex dielectric constant, ε.sup.∞ : high frequency term not contributing to conduction, ε d : term due to normal conduction electrons (or free electron gas), which conforms to Drude's formula and is defined as; ε.sub.d =ε.sub.1d -iε.sub.2d, provided ##EQU2## where τ: relaxation time of carrier ω p : plasma frequency N: electron density m * : effective mass of electron ε s : term due to superconduction electrons and defined as; ε.sub.s =ε.sub.1s -iε.sub.2s where ε 0 ε 2s =σ 1s /ω and ε 0 ε 1s =-σ 2s /ω, σ 1s and σ 2s being the real part and the imaginary part of the optical conductivity spectrum of a superconductor and conforming to Mattis-Bardeen's rule, and f n : ratio of the number of normal conduction electrons to the total numbers of electrons contributing to conduction. The real part σ 1s and the imaginary part σ 2s which conform to Mattis-Bardeen's rule are expressed as follows: ##EQU3## σ n : electric conductivity under normal conduction. The following formula (1A) expresses the transmission spectrum T at a higher precision than formula (1). T=T.sub.0,j =t.sub.o,j ·t.sub.o,j.sup.* ( 1A) wherein, ##EQU4## where r k ,l represents the phase and amplitude of light once reflected through the k-th to the l-th layers in a multiple-layered film composed of j layers, t k ,l represents the phase and amplitude of light once transmitted through the k-th to the l-th layers in a multiple-layered film composed of j layers, and e -i Δ.sbsp.n represents the phase shift and damping in the material of the n-th layer, in which Δ n =(d n /λ)/2π+ie - α.sbsp.n.spsb.d.sbsp.n, d n being the thickness of the n-th layer and α n being the damping of the n-th layer. The real part σ 1S and the imaginary part σ 2S of the optical conductivity spectrum of a superconductor may preferably conform to Leplae's theory, as defined by the following formule: ##EQU5## with ε, ε': energy of a single particle electron measured from Fermi surface, ε' being the energy under an excited state, (E): (EE'-Δ 2 )/|εε'|, Δ: energy gap, σ 1d : σ 0 /(1+ω 2 τ 2 ) [derived from Drude's equation], ##EQU6## σ 0 : direct current electric conductivity, and V F : Fermi velocity. There is also provided, according to the present invention, a process for forming a superconductor film on a substrate, comprising: using the evaluation method of the present invention to evaluate characteristics of a superconductor during the growth thereof on a substrate; and controlling a process condition based on the evaluation. The present inventive process for forming a superconductor film ensures that the characteristics of a superconductor film are evaluated at any time during the growth thereof and the results of the evaluation are fed back to adjust the process conditions and thus control the growth of the film to an optimum condition providing the formed film with a good crystalline structure. The forming of the superconductor film on the substrate may be carried out by a usual process for forming a film on a substrate, such as a chemical vapor deposition (CVD), a molecular beam epitaxy (MBE), a sputtering, or a vapor deposition. According to the present invention, there is also provided an apparatus for forming a superconductor film on a substrate, comprising: a growth chamber in which a superconductor film is formed on a substrate; a means for measuring a light transmittance of a superconductor film on the substrate; and a mechanism for transferring the substrate and the film between the growth chamber and the means for measuring a light transmittance. The means for measuring a light transmittance of a superconductor film preferably comprises: a portion for generating light; a portion for detecting light; a light pipe for communicating the light generating portion with the light detecting portion; and a means, inserted in the light pipe, for supporting the substrate with the film at the path of light passing through the light pipe; wherein the mechanism for transferring the substrate and the film is able to transfer the substrate and the film between the growth chamber and the substrate supporting portion of the means for measuring a light transmittance of the film. Preferably, an intermediate space is provided between the growth chamber and the substrate supporting means, for a temporary containing of the substrate and the film when moving between the growth chamber and the substrate supporting means. The present inventive apparatus preferably further comprises a temperature regulator and a pressure regulator for maintaining a temperature and a pressure in the intermediate space at a value between those of the growth chamber and those of the substrate supporting means. The present inventive apparatus for carrying out the present inventive process may be arranged by incorporating a device for measuring the light transmittance in a conventional apparatus for forming a film on a substrate, such as a chemical vapor deposition apparatus, a molecular beam epitaxy apparatus, a sputtering apparatus, a vapor deposition apparatus, or the like. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 schematically illustrates a measurement of the transmittance of a superconductor film formed on a substrate; FIG. 2 shows a typical arrangement of Michelson interferometer; FIGS. 3 (a), (b), and (c) are graphs showing (a) an observed experimental transmission spectrum in comparison with a theoretical transmission spectrum of a superconductor not containing normal conduction electrons (f n =0), (b) these spectrums matched by using f n as a parameter according to the present invention, and (c) the theoretical transmission spectra corresponding to different values of the number of normal conduction electrons or fitting parameter f n ; FIG. 4 schematically illustrates a light-transmitting material having a multiple-layered structure; FIG. 5 schematically illustrates reflection and transmission of light through two layers; FIG. 6 is a graph showing a matching of the theoretical and the experimental transmission spectra to yield a f n of 0.75, according to a preferred embodiment of the present invention; FIG. 7 is a graph showing another matching of the theoretical and the experimental transmission spectra to yield an f n of 0.6-0.7, according a more preferred embodiment of the present invention; FIG. 8 shows an arrangement of an apparatus for forming superconductor films according to the present invention; and FIG. 9 shows a process sequence according to the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS The principle of the present invention will be described below. The ratio of the number of normal conduction electrons to that of superconduction electrons (hereinafter referred to as "the normal/superconduction electron number ratio") is obtained on the following basis. Substances have a specific wave length of light which can be easily absorbed by or transmitted through the substance and the characteristics of the substance can be determined by the measurement of such wave lengths. The present inventors found that, by utilizing this phenomenon, the normal/superconduction electron number ratio of superconductors having a complicated crystalline structure can be determined. The optical conductivity spectrum of substances has been studied and clarified for the conventional normal conductors or superconductors, but the recently found and developed oxide superconductors have a complicated crystalline structure and consist essentially of a mixed crystal, in which the normal conduction electrons and the superconduction electrons coexist and both the normal conduction and superconduction electrons must be collectively taken into consideration when determining the optical conductivity spectrum. The optical conductivity spectrum, σ, has a relationship with the complex dielectric constant ε, as expressed by the formula: σ=ωε.sub.0 ε, where ω is the frequency of light and ε 0 is the dielectric constant of vacuum. Assuming a sample is a mixed crystal of a normal conductor and a superconductor, the complex dielectric constant ε of the sample can be expressed as: ε=ε.sup.∞ =f.sub.n ε.sub.d +(1-f.sub.n)ε.sub.s (2) where ε: complex dielectric constant, ε.sup.∞ : high frequency term not contributing to conduction, ε d : term due to normal conduction electrons (or free electron gas), which conforms to Drude's formula and defined as; ε.sub.d =ε.sub.1d -iε.sub.2d, provided ##EQU7## where τ: relaxation time of carrier ω p : plasma frequency N: electron density m * : effective mass of electron ε s : term due to superconduction electrons and defined as; ε.sub.s =ε.sub.1s -iε.sub.2s where ε 0 ε 2s =σ 1s /ω and ε 0 ε 1s =-σ 2s /ω, σ 1s and σ 2s being the real part and the imaginary part of the optical conductivity spectrum of a superconductor which conforms to Mattis-Bardeen's rule [see D. C. Mattis and J. Bardeen, "Theory of Anomalous Skin Effect in Normal and Superconducting Metals", Phys. Rev. Vol. 111, pp. 412-417, 15 July 1985], and f n : ratio of the number of normal conduction electrons to the total numbers of electrons contributing to conduction. Consequently, the transmission spectrum T is expressed as: ##EQU8## where R: reflectance, n: real part of complex refractive index, k: imaginary part of complex refractive index, α: absorption coefficient, d: thickness of sample. The optical conductivity spectrum has been studied as a physical quantity expressing the material nature, but in the experimental field, information about the transmission spectrum best expresses the material property. This is the reason for using the transmission spectrum derived from the optical conductivity spectrum, instead of the latter. By using f n as a parameter and matching an experimental transmission spectrum with the theoretical spectrum, the normal/superconduction electron number ratio can be obtained. Preferably, the normal/superconduction electron number ratio is obtained from the infrared or far-infrared transmission spectrum. The present invention will be described in more detail by way of Examples. EXAMPLE 1 The normal/superconduction electron number ratio of an oxide superconductor film is estimated in the following sequence, according to the present invention. FIG. 1 schematically illustrates the principle of the measurement of an infrared transmission spectrum. The transmission spectrum of a superconductor film 12 formed on a substrate 11 is obtained by irradiating an infrared or far-infrared ray 13 to the film 12, and measuring the transmitted light 14 by an infrared or far-infrared ray detector 15. The normal/superconduction electron number ratio of the superconductor 12 is derived from the thus-obtained transmission spectrum. FIG. 2 shows a Michelson interferometer used for measuring the transmission spectrum. An infrared or far-infrared ray introduced through an optical window 21 is irradiated to a sample 23 via a light pipe 22, and the infrared or far-infrared ray transmitted through the sample 23 is detected by a detector 24 such as a bolometer. In the figure, 201 denotes a light source, 202 a chopper, 203 a collimator, 204 a beam splitter, 205 a stationary mirror, 206 a movable mirror, 207 a focus mirror, 208 a filter, 209 a coolant such as liquid nitrogen or liquid helium, and 210 a cryostat. The above-observed values are analyzed by comparing same with the theoretically calculated values, to provide the normal/superconduction electron number ratio. FIG. 3 (a) shows a transmission spectrum obtained by a measurement of an approximately 150 nm thick Bi-superconductor film formed on an approximately 0.4 mm thick MgO substrate by a chemical vapor deposition (CVD) process. The measurement was carried out over a range of the light frequency of from 50 to 300 cm -1 , and the observed transmittance varies continuously with respect to the frequency, as shown by the broken curve. The solid curve represents the theoretical transmission spectrum for an ideal or pure superconductor. This result shows that the actual sample (23) is a mixed crystal of a normal conductor and a superconductor. FIG. 3 (b) shows a comparison between the above-observed spectrum and the theoretical spectrum for a normal/superconduction electron number ratio f n =0.7, in which both spectrums match very well to thus prove that the sample has a normal/superconduction electron number ratio of 0.7 to 0.8. The theoretical spectrum varies with the matching parameter f n as shown in FIG. 3 (c). The f n value at which the observed and the theoretical spectra best match is the ratio of the normal/superconduction electron number ratio of the sample subjected to the measurement. As described above, the present inventive evaluation method enables the normal/superconduction electron number ratio of superconductors to be easily obtained. EXAMPLE 2 For a material having a multi-layer structure as shown in FIG. 4, the transmission spectrum T of light is calculated in the following manner. Considering a multiple reflection by two layers as shown in FIG. 5, the reflected light and the transmitted light are expressed, respectively, as: ##EQU9## with r k ,l : light once reflected when the k-th through the l-th layers are supposed to be monolithic, t k ,l : light once transmitted when the k-th through the l-th layers are supposed to be monolithic, e -i Δ.sbsp.n : phase shift and damping in the n-th layer, Δ n =(d n /λ)2π+ie - α.sbsp.n.spsb.d.sbsp.n, d n being the thickness of the n-th layer and α n being the damping factor of the n-th layer. Thus, the reflected light and the transmitted light for a film composed of j layers of FIG. 4 can be expressed as: r.sub.0,j =r.sub.0,j-1 +(t.sub.0,j-1 ·t.sub.j-1,0 e.sup.-2iΔ.sbsp.j)/(1+r.sub.j-1,0 r.sub.j-1,j e.sup.-2iΔ.sbsp.j) t.sub.0,j =(t.sub.0,j-1 t.sub.j-1,j e.sup.-iΔ.sbsp.j)/(1-r.sub.j-1,0 r.sub.j-1,j e.sup.-2iΔ.sbsp.j) By using the above-equations, the reflected light and the transmitted light for a structure composed of j layers can be calculated by a layer-by-layer calculation from the first layer to the j-th layer, to provide expressions for the transmission spectrum T and the reflection spectrum R as follows: T=T.sub.0,j =t.sub.o,j ·t.sub.o,j * R.sub.0,j =r.sub.0,j ·r.sub.0,j * Using this theoretical spectrum T, the transmission spectrum T can be calculated for the same sample as used in Example 1. The sample of Example 1 has a structure of BSCCO/MgO, in which j=3, i.e.; 0, 3: vacuum, 1: Bi--Sr--Ca--Cu--O superconductor film, and 2: MgO-substrate. T is expressed as: T=(T.sub.0,2 T.sub.2,.sbsb.3 e.sup.-αd)/(1-R.sub.2,.sbsb.0 R.sub.2,.sbsb.3 e.sup.-2αd) Using this expression, the transmission spectrum T is obtained in the same sequence as in Example 1, as shown in FIG. 6. The result shows that the normal/superconduction electron number ratio f n =0.75. In Example 1, the calculation was carried out without considering the presence of the MgO substrate. In Example 2, the calculation involves the effect of the MgO substrate and provides a more precise evaluation of f n . When a sample has a high f n value, the calculations of both Example 1 and Example 2 give substantially the same f n value as seen from FIG. 6 and FIG. 3(c). Therefore, when the f n is expected to have a high value, the simpler calculation as used in Example 1 is preferable. This embodiment also provides an evaluation of a multi-layer film composed of superconductive, normal conductive, and insulating layers. EXAMPLE 3 In Example 1, the transmission spectrum T was calculated on the assumption that the optical conductivity spectrum conforms to Mattis-Bardeen's rule. Mattis-Bardeen's theory is best applied in those cases in which a wave number ω g corresponding to the energy gap Δ is smaller than the inverse number of the life time τ of quasiparticles (ω g <<1/τ), as in the metallic superconductors. In Example 1, the transmission spectrum T was calculated by using this theory. The embodiment of Example 3 provides a more precise evaluation of the transmission spectrum T. Considering a relatively higher ω g value of the Bi containing or the copper oxide containing superconductors (ω g >>1/τ), it is more advantageous to use an optical conductivity spectrum conforming to Leplae's theory instead of Mattis-Bardeen's rule, as described below. According to Leplae's theory (see L. Leplae, Phys. Rev. Vol. B27 (1983), p. 1911), the real part σ 1s and the imaginary part σ 2s of the optical conductivity spectrum T can be expressed as: ##EQU10## where ε, ε': energy of a single particle electron measured from Fermi surface, ε' being the energy under an excited state, (E): (EE'-Δ 2 )/|ε ε'|, Δ: energy gap, σ 1d : σ 0 /(1+ω 2 τ 2 ) [derived from Drude's equation], σ 0 : direct current electric conductivity, and V F : Fermi velocity. ##EQU11## By using these σ 1s and σ 2s and incorporating the above-mentioned multiple-layer effect, the transmission spectrum T is calculated in the same sequence to yield the result as shown in FIG. 7, in which ω p =800 cm -1 , τ=2×10 -14 sec, ω g =200 cm -1 , and d=0.05 μm. A comparison of this calculated T with the experimental T shows that f n =0.6-0.7. This embodiment of the present invention provides a more precise evaluation of the transmission spectrum T by using Leplae's theory, in which the relationship between the energy gap Δ and the quasiparticle life time τ is taken into consideration. EXAMPLE 4 An apparatus for forming a superconductor film by using the present invention evaluation method will be described below. FIG. 7 shows an arrangement of an apparatus for forming superconductor films, such as a CVD apparatus, a vapor deposition apparatus, a sputtering apparatus, an MBE apparatus, or the like, and which incorporates a device for measuring the transmittance similar to the device used in Example 1. A superconductor film 12 (FIG. 1) formed on a substrate 11 (FIG. 1) in a growth chamber 3 can be transferred between the growth chamber 3 and a film supporting portion 4 by a transfer mechanism 2. The provision of the transfer mechanism 2 enables the superconductor film growing on the substrate to be taken out of the growth chamber 3 at any time during the growth for a measurement of the infrared or far-infrared transmission spectrum. After the measurement, the film can be returned to the growth chamber 3, to effect the subsequent growth. The inside of a film supporting portion 4 of the infrared or far-infrared spectrometer is evacuated by a vacuum pump 7 and maintained at a vacuum, and a cooler 5 is cooled by a refrigerator 8. An infrared or far-infrared ray generated in an infrared or far-infrared ray interferometer 9 is irradiated to a superconductor film through a light pipe 6, and the transmitted infrared or far-infrared ray is measured by a detector 1. As shown in FIG. 8, an intermediate space 10 is provided between the film growth chamber 3 and the film supporting portion 4. The inside of the intermediate space 10 is maintained at a temperature and a pressure between those of the growth chamber 3 and the supporting portion 4 by a not-shown regulator, to avoid an abrupt thermal change in the transported film and an influence between the atmospheres of the growth chamber 3 and the supporting portion 4. EXAMPLE 5 A process for forming superconductor films by using the present inventive evaluation method may be carried out in the apparatus as shown in FIG. 8. FIG. 9 shows a process sequence according to the present invention. In FIG. 9, the reference numerals in parentheses [(1) to (6)] represent the process sequence or steps and the numerals without parentheses [3, 5, and 10] correspond to those of the apparatus shown in FIG. 8. Step (1) A substrate is placed in the film growth chamber 3 and held at a growth temperature to grow a Bi--Sr--Ca--Cu--O superconductor film on the substrate. Step (2) After the film has grown to a certain thickness, the substrate and the film are transferred to the intermediate space 10 and cooled to around room temperature. Step (3) The substrate and the film are then transferred to the cooler 5 of a measuring apparatus, to measure the transmission spectrum T by the method according to the present invention. The film is evaluated from the measured transmission spectrum. Step (4) The substrate and the film are then transferred to the growth chamber through the intermediate space 10. Step (5) In the growth room 3, the film is allowed to grow on the substrate again under a growth condition different from the initial condition of Step (1), if necessary, based on the evaluation obtained at Step (3). Step (6) The substrate and the film are transferred to the intermediate space 10 for a further evaluation. The step cycle (1)-(6) is repeated until the film has been grown to a desired thickness. Namely, the film is taken out of the growth chamber, for an evaluation thereof, at any time during the growth thereof and the evaluation film property is fed back to change the process conditions to thus obtain a controlled film property. This is also applicable when forming of a multi-layer film, using the same apparatus as shown in FIG. 8. The present invention is applicable not only to a film sample but also to a bulk sample which transmits light. The superconductor must be carefully formed under a precisely controlled condition, because the superconductive property is very dependent upon the chemical composition. The provision of an infrared or far-infrared ray spectrometer in an apparatus for forming superconductor films enables a growing superconductor film to be taken out of a film growth chamber at any desired time, for a measurement of the normal/superconduction electron number ratio, to thus provide a frequent feedback for changing the film formation conditions, to thereby ensure a controlled optimum condition for a desired superconductive property. As herein described, the present invention provides a method of evaluating a superconductor at a high precision even when a mass to be evaluated is as small as that of a film. The present invention also provides a process and an apparatus for forming superconductor films, in which a superconductor film can be evaluated at any time during the growth or formation process thereof, to obtain a superconductor film having a good crystalline structure and applicable to many purposes including electronic elements.

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CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of application Ser. No. 067,879 filed Aug. 20, 1979, now issued as U.S. Pat. No. 4,274,383. BACKGROUND OF THE INVENTION (1) Field of the Invention This invention relates to vaporizing liquid fuels and mixing the vapor with air for spark ignition in an internal combustion engine. (2) Description of the Prior Art Automobiles are powered almost exclusively by internal combustion engines. With the advent of the energy shortage, people became concerned with the number of miles per gallon that their cars could get. Many cars on the road today have large engines which can produce much more power than is necessary to go the speed limit. These large engines use a great deal of gas. Many methods have attempted to increase the gas mileage of these large engines. These attempts to increase the performance of large engines have met with only varying degrees of success. One area for improvement is better vaporization of the liquid fuel. Different methods for controlling the amount of vapor have been tried. Many inventors have attempted to control the vapor flow by controlling the amount of fuel which is vaporized. This method is usually unsatisfactory as it is very difficult to regulate the rate of vaporization as opposed to the rate of introduction of air into the vaporizer. Before filing this application, applicant caused a search of the prior art to be made at the United States Patent and Trademark Office. That search disclosed the following patents: ______________________________________GRONKWIST 1,625,997MENGELKAMP 2,821,843AUTHEMENT 3,963,013PIERCE 4,074,666TOTTEN 4,106,457QUINN 4,146,002______________________________________ QUINN discloses a fuel preheater using hot water from the car's cooling system to vaporize fuel which is mixed with air and forwarded to the carburetor. TOTTEN discloses a fuel vaporizer for vaporizing fuel using hot water and having a valve for adjusting the amount of fuel sent into the vaporizer. It appears that the other patents listed are of general interest only. These prior patents show that the vaporization of gas and mixing it with air before it reaches the carburetor increases the gas mileage. However, one of the most perplexing problems has been the regulation of the flow of the vapor into the carburetor. Another problem in the art has been the maintenance of a steady heat in the vapor mixing compartment. SUMMARY OF THE INVENTION (1) New and Different Function I have invented a way to improve the gas mileage which may be achieved with internal combustion engines. My invention does not increase the power of the engine, in fact, it is known that preheating the fuel-air vapor before it enters the engine has a tendency to reduce the total output of the engine. In view of the fact that automobiles on the road today have engines which generate far more power than is necessary or present speed limits, the increase in efficiency greatly outweighs the loss of power. I have found that great results are achieved when the introduction of the fuel vapor can be regulated. My system vaporizes fuel at a rate greater than is necessary to be introduced into the carburetor. The amount of fuel vapor entering the carburetor is varied by varying the amount of air allowed to enter the vaporizer. In this manner I am able to accurately control the amount of vapor introduced into the carburetor and thereby increase the total efficiency of the car's engine. Thus it may be seen that the function of the total combination far exceeds the sum of the functions of the float valves, air filters, etc. (2) Objects of this Invention An object of this invention is to vaporize fuel for an internal combustion engine. Another object is to vaporize fuel and thoroughly mix the vapor with air. Further objects are to facilitate adjusting the flow of the vapor-air mixture into the carburetor. Further objects are to achieve the above with a device that is sturdy, compact, durable, lightweight, simple, safe, efficient, versatile, ecologically compatible, energy conserving, and reliable, yet inexpensive and easy to manufacture, install, adjust, operate and maintain. Other objects are to achieve the above with a method that is versatile, ecologically compatible, energy conserving, rapid, efficent, and inexpensive, and does not require highly skilled people to install, adjust, operate, and maintain. The specific nature of the invention, as well as other objects, uses, and advantages thereof, will clearly appear from the following description and from the accompanying drawing, the different views of which are not scale drawings. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic representation showing the organization of the fuel vaporizer with an automobile engine; FIG. 2 is a side elevational view of a vaporizer according to my invention; FIG. 3 is a longitudinal section of the vaporizer according to my invention; FIG. 4a is a top plan view of the backfire check valve; FIG. 4b is a sectional view of the check valve; FIG. 5a is a side view of the vaporizer showing the placement of one of the fuel reservoir tanks; FIG. 5b is an end view of the vaporizer showing both fuel reservoir tanks and the fuel supply lines; FIG. 5c is a top view of the vaporizer showing the fuel return line and the opposed nature of the float valves within the fuel reservoir tanks; FIG. 5d is a bottom view of the vaporizer showing the opposed nature of the fuel supply lines from the fuel reservoir tanks to the vaporizer; and FIG. 6 is a perspective view of the air filter on the engine carburetor showing the fuel-air introduction unit according to my invention. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to FIGS. 1 and 3 of the drawing, hot water is transmitted from the cooling system on engine or motor 16 (which includes radiator 10, water pump 14, and heater 32) through hot water line 12 to hot water inlet 18 of vaporizer 20. The hot water is introduced into heat exchanger 22 of the vaporizer. The hot water is forced through heat exchanger 22 and out through return water outlet 28 back to the engine via water return line 30. After the car's engine is warm, solenoid valve 34 may be electrically opened and solenoid valve 36 closed thereby diverting the liquid fuel from fuel line 38 to vaporizer inlet line 40 into fuel reservoir tanks 42a and 42b, which are mounted on the sides of vaporizer 20. In alternate embodiments, valve 34 may be eliminated and the inlet line 40 may always be open. The level of the fuel in the fuel reservoir tanks 42a and 42b is controlled by fuel float valves 44a and 44b (See FIG. 5c). The fuel inlet line 40 terminates at fuel float valves 44a and 44b. When the fuel level drops, the valves are opened and more fuel enters fuel reservoir tanks 42a and 42b. It will be apparent to those skilled in the art that fuel float valves 44a and 44b are mounted in opposite directions. This mounting technique will have the effect of counteracting any yaw or pitch which may result from rapid maneuvers of the automobile in which vaporizer 20 may be mounted. Heat radiates from the heat exchanger 22, heating some of the fuel in the pool to a vapor state. The fuel vapor then rises from vapor compartment 120 through spacer grill 52 and through holes 50 into vapor mixture compartment 54. Outside air enters the vaporizer 20 through an air inlet system. As air enters the inlet system it passes through one of three separate sections of vaporizer air filter 56 and proceeds through air inlet 58 into vapor compartment 120 or through air inlet 60 and control valve 62 into vapor mixture compartment 54. Air may also be drawn into vapor compartment 120 through sparge tube 64. Sparge tube 64 draws air into vapor compartment 120 down into the fuel area and thereby assists in the vaporization thereof. Sparge tube 64 also acts as a surge retarder and thereby prevents unwanted sloshing of the fuel. The vapor-air mixture is transmitted through vapor outlet 69 through vapor line 70 to the carburetor 72. Check valve 74 is located below vaporizer air filter 56 in the air inlet 58. The check valve, shown in FIGS. 4a and 4b, has two discs, upper disc 76 and lower disc 78. Lower disc 78 is suspended by piston 80 below the upper disc. The lower disc has a diameter less than the diameter of air conduit 58 while the upper disc 76 has a diameter equal to the diameter of the air conduit 58. Upper disc has five check valve holes 82 arranged around the termination 84 of the piston. In the operating, down position, air passes through holes 82 and around the perimeter of lower disc 78 into the vapor compartment 120. In the case of a backfire, the lower disc 78 is forced up against the upper disc 76 effectively closing the air supply into and out of the air inlet 58 from the vapor compartment 120. Spring 85 holds the lower disc 78 up in the closed position when there is no air flow as seen by the arrows in FIG. 4b. This prevents the flow of vapors through the filter 56 when the engine is stopped. Also located in air conduit 58 is control valve 75. Control valve 75 and control valve 62 are both vacuum operated butterfly valves. In the embodiment of the invention actually constructed, control valves 75 and 62 are operated utilizing engine vacuum; however, it is within the intended scope of this disclosure that alternate methods of control, including, but not limited to, electric, electromechanical or electronic microprocessor based control systems may be utilized to operate control valves 75 and 62. Control valve 75 has the effect of increasing or decreasing the amount of vapor created in vaporizer 20, over and above that minimum amount created by means of air which enters via sparge tube 64, by metering the amount of air allowed to enter vapor compartment 120. Air entering vapor compartment 120 through control valve 75 is distributed through air manifold 77. Air manifold 77 is constructed with small perforations in its upper surface and larger holes in the lower surface. Experimentation has shown this configuration will aid in fuel vaporization. Control valve 62 is utilized to control the richness or leanness of the vapor mixture by adding air to the vapor mixture in vapor mixture compartment 54. FIGS. 5a, 5b, 5c and 5d depict the novel configuration of fuel reservoir tanks utilized in the illustrated embodiment of my invention. FIG. 5a shows a side view of vaporizer 20 with fuel reservoir tank 42b. Overflow tubes 43c and 43d prevent the level of fuel present in vapor compartment 120 from rising too high under the vacuum created by carburetor suction. Overflow tubes 43c and 43d are present at either end of fuel reservoir tank 42b to compensate for nonhorizontal positioning during automobile maneuvering. FIGS. 5b and 5d depict the connection of fuel supply lines 47a and 47b to fuel supply header 45. As depicted in FIG. 5d, the fuel supply lines are connected to fuel reservoir tanks 42a and 42b at opposite ends. This connection configuration, along with the opposing float valve configuration previously discussed, will have the effect of negating transient changes in attitude of vaporizer 20. Carburetor air filter 86 is fitted to receive vapor line 10 which terminates in air filter intake 88 and it is through this intake that the air-fuel vapor is introduced into the carburetor 72. Carburetor air filter 86 is depicted in FIG. 6. Air filter intake 88 also includes control valve 90. Control valve 90 is utilized to control the aperture of air filter intake 88. During cold start operation, when the engine is utilizing liquid fuel, control valve 90 opens and allows outside air to enter carburetor 72. When the temperature of the cooling system of the car is sufficiently high to permit gas vaporization, control valve 90 is closed and valves 34 and 36 shift positions. Liquid fuel is no longer utilized by carburetor 72 and vaporized fuel enters air filter intake by means of vapor line 70. Control valve 90 is vacuum operated in the embodiment disclosed and may be enabled utilizing an electric solenoid at the point where operating temperatures will permit vaporization. Again, as discussed above, alternate embodiments of the fuel vaporization techniques taught in this application may utilize electrically operated control valves in place of vacuum operated valves. In an embodiment not shown in the accompanying figures, a small line may be inserted into carburetor air filter 86 to detect the vacuum present at the carburetor intake port. The vacuum thus detected may be utilized directly or indirectly to control any or all of the vacuum operated control valves depicted herein. The embodiment shown and described above is only exemplary. I do not claim to have invented all the parts, elements or steps described. Various modifications can be made in the construction, material, arrangement, and operation, and still be within the scope of my invention. The limits of the invention and the bounds of the patent protection are measured by and defined in the following claims. The restrictive description and drawing of the specific example above do not point out what an infringement of this patent would be, but are to enable the reader to make and use the invention.

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BACKGROUND OF THE INVENTION a. Field of the Invention This invention relates to apparatus useful in the assembly of certain types of devices, for example, hand-wired printed circuit boards. B. Description of the Prior Art It is common in the art of printed circuit board wiring to utilize a multi-pin connector including a base upon which are mounted a plurality of electrically conducting pins, the pins being regularly spaced and mounted perpendicular to the base. A standard practice is to construct printed circuit boards having a plurality of holes extending therethrough, the holes being regularly spaced to coincide with the spacing of the pins on the connector. Electrical connections are made between the board and the connector by mounting the board upon a connector, hand placing one or more solder washers over the pins extending through the holes to be electrically connected, and passing a heat source over the board and connector to melt the solder. In such a wiring process, it is commonly required to place two solder washers on each pin of the connector, with 70 or more pins to each connector. Thus, it is necessary to place 140 or more of the solder washers by hand and one at a time for each connector used. Because the solder washers are commonly quite small, on the order of 0.075 inches outside diameter and 0.020 inches thick, the hand placing of the washers is a very precise and tedious process. Obviously, the labor associated with such an operation greatly increases the cost of building such a circuit. SUMMARY OF THE INVENTION It is an object of this invention to provide a tool which will accurately and quickly position a large number of components such as solder washers onto the connecting pins of a wiring circuit. It is a further object to provide such a tool which will place a predetermined number of components such as solder washers onto each pin. It is a still further object to provide such a tool having the further advantages of portability, low cost construction, and ease of use at a wiring workbench. An apparatus having these and other objects, and appropriate for the assembly of components each having a hole therethrough, onto the pins of a structure having a plurality of pins positioned in a predetermined manner on a base, may include: a jig having extending therethrough a plurality of apertures positioned in an identical pattern to the pins, the apertures being sufficiently large to admit the components, a slidably removable element shaped to fit below the jig and to prevent the components from falling through the apertures, means for randomly scattering the components over the surface of the jig until each aperture is filled with at least one of the components, and means for removing the element, thereby allowing the components within said apertures to fall onto the pins of a base properly positioned thereunder. BRIEF DESCRIPTION OF THE DRAWINGS The invention, and the description thereof which follows will be more fully understood when considered together with the figures in which: FIG. 1 shows an electrical connector illustrative of the type with which the invention may be used; FIG. 2 illustrates a loading apparatus comprising a part of the invention; FIG. 3 illustrating a jig to be used with the loading apparatus of FIG. 2; FIG. 4 illustrates a top view of the slide shown in FIG. 3; FIG. 5 illustrates certain spatial relationships of various elements utilized in the practice of the invention, and FIG. 6 is an end view of the jig shown in FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT The invention has particular utility in the rapid and efficient mounting of solder washers onto the pins of an electrical connector of the type illustrated in FIG. 1. A non-conducting base 13 has mounted on it a plurality of conducting pins 14--14, the pins being usually mounted in a regular fashion perpendicular to the base 13. Referring to FIG. 2, a preferred loading apparatus 11 is shown. It includes a substantially U-shaped base 12, including a reservoir 15 and a channel 16. A cover 17 is mounted to the base with hinges 20--20. A barrier 21 is secured to the cover such that when the cover is closed on the base, the combination of the raised lip 22 and the barrier 21 effectively seal the periphery of the top of the base 12. A space, however, is left at the top of the wall 25 separating the reservoir 15 from the channel 16. An optional pair of bracing members 18--18 may be secured within the channel 16 as more fully described below. Referring to FIG. 3, a jig 26 is constructed with dimensions such that it may be inserted snuggly into the channel 16 of the apparatus of FIG. 2. On the surface 32 of the jig are a plurality of holes 27-27, the holes being regularly spaced on centers coinciding with the centers of the pin arrangement of the electrical connector shown in FIG. 1. As more clearly shown in FIG. 6, the underside of the jig 26 has a channel 30 into which a slide 31 may be snuggly fitted. The channel 30 must extend through at least one end of the jig 26 to admit the slide 31, and must pass under all of the holes 27--27. The depth of these holes, being the distance between the surface 32 of the jig 26 and the channel 30 as shown in FIG. 6, is substantially the height of the number of washers to be stacked upon each pin. A removable insert 35 is constructed to fit flush with the surface 32 of the jig 26. The insert may have a pair of ears 36 and 37 which fit snuggly into grooves 40 and 41 respectfully. When the insert 35 is mounted upon the jig 26 the holes 27--27 are effectively sealed such that any components within the holes are prohibited from falling out when the jig 26 is rotated. As a convenience, latches (not shown) may be applied adjacent to the grooves 40 and 41 to be moved over the ears 36 and 37 to lock the insert 35 in place once the jig 26 is loaded with washers. Referring to FIG. 4, a top view of the slide 31 is illustrated, together with a necessary size relationship of the solder washers and the pins to be used with the invention. Specifically, the slide 31 has a pair of slots 42 and 45 constructed such that the slide may be mounted upon the electrical connector of FIG. 1 with the pins 14--14 of the connector protruding through the slits. Note that the slits extend all the way to the edge on one end of the slide 31. As is easily seen in FIG. 4, the width of the slits 42 and 45 must be large enough to accommodate the pins 14--14. Further, it is necessary that the width of the slits be sufficiently small that the solder washers 46--46 will not fall through the slits when the washers are inserted onto the protruding pins 14--14. It is necessary, therefore, that the width of the slits 42 and 45 is larger than the outside diameter of the pins 14--14 and smaller than the outside diameter of the solder washers 46--46. FIG. 6 illustrates an end view of the jig 26. A channel 30 is constructed such that the slide 31 will fit snuggly therein, as shown in FIG. 3. The holes 27--27 extend from the surface 32 of the jig to the channel 30 such that when the slide 31 is inserted into the groove, washers inserted into the holes 27--27 will rest upon the top of the slide 31. As stated previously, the depth of the holes 27--27 is substantially equal to the height of the number of solder washers to be stacked on each pin. To use the apparatus, the reservoir 15 is first provided with a quantity of solder washers. The slide 31 is inserted into the channel 30 of the jig 26 and the jig is inserted into the channel 16 of the loading apparatus 11. If the optional bracing members 18--18 are present, they should be fitted to fill the slots 42 and 45 of the slide 31 when it is in place in the channel 16. In this way, additional support is provided for the jig 26 during the loading of the washers. The insert 35 is not used at this time. The cover 17 of the loading apparatus is closed and the apparatus is shaken by hand to scatter the washers out of the reservoir and onto the survace 32 of the jig 26 by way of the previously mentioned space above the wall 25. The operator may observe through the clear plastic of the cover 17 when the holes 27--27 of the jig are filled, or are substantially filled, with washers. At that time the cover 17 is lifted and those solder washers remaining on the surface of the jig are pushed into any remaining unfilled holes, or back into the reservoir 15. After observing that all of the holes 27--27 are filled with washers, the operator places the insert 35 onto the surface of the jig to prohibit the washers from falling out of the holes, the jig and slide are removed from the loader. The jig-slide-insert combination is then mounted upon the pins of a connector 13 such that the pins of the connector protrude through the slits of the slide 31 and the holes of the jig 26, to rest against the bottom side of the insert 35. By this process, the pins are also automatically placed through the holes of the solder washers which were previously shaken into the holes of the jig. The configuration at this point is shown clearly in FIG. 5. The jig 26 has been omitted from this drawing to more clearly indicate what exists within. The slide 31 is now pulled laterally and removed from the apparatus. This results in the washers 50--50 falling down the pins 14--14 onto the surface of the printed circuit board 51. With the removal of the jig 26, the construction process is completed. All that remains to finish the soldering sequence is to pass a radiant energy source across the surface of the P. C. board to heat and melt the washers, thereby perfecting the electrical connection. While the foregoing description is of an apparatus for stacking two washers on each pin, it is obvious that more or fewer washers may be stacked by merely changing the depth of the jig. Similarly, various jigs may be provided with different hole spacings to accommodate different pin arrangements. Furthermore, different aperture (hole) shapes and sizes could be provided to accommodate different kinds of components.

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BACKGROUND OF THE INVENTION The invention relates to a fuel tank for a motor vehicle, having a chamber which is delimited by a wall and is used to hold fuel and having an activated carbon filter which is provided for the purpose of ventilating the area of the chamber located above the fuel during refueling and/or during operation. Fuel tanks of this type are in widespread use in modern motor vehicles and are known in practice. The activated carbon filter has a housing which is made from the plastics polyamide or polypropylene and is partly reinforced with glass fibers and is connected to the chamber via a line which leads through the wall of the fuel tank. A drawback of the known fuel tank is that fuel vapors can escape into the environment through the connections of the fuel tank and the activated carbon filter, for example through leaks, diffusion or permeation. The invention is based on the problem of configuring a fuel tank of the type described in the introduction in such a way that fuel is particularly reliably prevented from escaping. BRIEF DESCRIPTION OF THE INVENTION According to the invention, this problem is solved through the fact that the activated carbon filter is arranged in the region of the chamber. This configuration means that the fuel tank according to the invention does not require any connecting lines between the chamber and the activated carbon filter. Therefore, the connection between the activated carbon filter and the chamber of the fuel tank does not have any contact with the environment. Therefore, in the event of a leak or as a result of diffusion and permeation at the connection between the activated carbon filter and the chamber, it is impossible for any fuel vapors to pass into the environment. The fuel tank according to the invention particularly reliably prevents fuel from escaping into the environment. A further advantage of the fuel tank according to the invention consists in the fact that it is particularly compact and has a particularly small number of components which are to be fitted in the motor vehicle. Moreover, the invention makes it easy for the activated carbon filter to be integrated in the intended outer contour of the fuel tank according to the invention. Over prolonged periods, the housing materials used in modern activated carbon filters are not able to withstand contact with liquid fuel. Therefore, consideration could be given to coating the housing of the activated carbon filter located inside the chamber or to making this housing from a fuel-resistant material. However, this makes the activated carbon filter expensive. However, according to an advantageous refinement of the invention, the activated carbon filter can be produced at particularly low cost if it is arranged inside a compensation tank arranged in the chamber. This configuration allows the compensation tank to protect the activated carbon filter from contact with liquid fuel. The fuel tank according to the invention is of particularly simple design if a wall of the compensation tank has a molded formation for holding the activated carbon filter. According to another advantageous refinement of the invention, it is possible to particularly reliably prevent the activated carbon filter from being wetted with fuel by securing the compensation tank and/or the activated carbon filter to the inner side of the upper wall of the fuel tank. A configuration in which the compensation tank and/or the activated carbon filter forms a preassemblable structural unit with a shell part which forms an upper wall of the fuel tank makes the fuel tank according to the invention particularly simple to assemble. Assembly of the fuel tank according to the invention is further simplified if housing parts of the activated carbon filter and/or of the compensation tank are joined by material-to-material bonding. This allows the components of the fuel tank to be, for example, welded without difficulty. According to another advantageous refinement of the invention, the number of connection points between the activated carbon filter and the chamber can be kept particularly small if connections for vent lines which are guided into the region above the fuel in the chamber are arranged in housing parts of the activated carbon filter and/or of the compensation tank. The chamber requires a line which leads via the activated carbon filter into the environment for the purpose of pressure equalization. According to another advantageous refinement of the invention, contact between liquid fuel and the connection of the line of the activated carbon filter which leads into the environment can be particularly reliably avoided if a vent line which is intended for pressure equalization with the environment is guided through a common region of the wall of the chamber and of the compensation tank or of the activated carbon filter. According to another advantageous refinement of the invention, assembly of the activated carbon filter in the compensation tank is further simplified if a housing part of the activated carbon filter is formed integrally with the compensation tank. This allows the activated carbon filter to be filled with activated carbon, welded closed and connected to the ventilation system during assembly. Finally, the compensation tank is welded closed. According to another advantageous refinement of the invention, protection against wetting of the activated carbon filter is further increased if a housing of the activated carbon filter is of double-walled design. According to another advantageous refinement of the invention, assembly of the activated carbon filter is further simplified if the activated carbon filter has a cartridge comprising activated carbon which can be inserted into the compensation tank. Connecting the activated carbon filter to the ventilation system of the fuel tank according to the invention requires particularly little assembly work if a line which is to be connected to the activated carbon filter has a plug connection part. BRIEF DESCRIPTION OF THE DRAWINGS The invention permits numerous embodiments. One of these is illustrated in the drawing and described below for the purpose of further explaining the basic principle of the invention. In the drawing: FIG. 1 diagrammatically depicts a fuel tank according to the invention having an activated carbon filter arranged in a compensation tank, FIG. 2 shows an activated carbon filter which is secured to an upper shell part of a further embodiment of the fuel tank according to the invention, FIG. 3 shows an activated carbon filter arranged in a molded formation of a compensation tank, FIG. 4 shows an activated carbon filter arranged in a base region of a compensation tank. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 diagrammatically depicts a fuel tank in longitudinal section, having a chamber 2 for holding fuel and having two shell parts 3 , 4 . A compensation tank 5 arranged in the fuel tank 1 has a housing part 6 of pot-shaped configuration and is secured to the upper of the shell parts 4 by material-to-material bonding. The upper shell part 4 has an edge 7 for this purpose. The base region of the pot-shaped housing part 6 of the compensation tank 5 is produced integrally with a housing part 8 of an activated carbon filter 9 . The housing part 8 is joined to a cover 10 by material-to-material bonding. The activated carbon filter 9 has a cartridge 11 comprising activated carbon which has been inserted into the housing part 8 . Of course, the activated carbon filter 9 can also be produced by activated carbon being introduced into the housing part 8 . Vent lines 12 lead into the compensation tank 5 through the upper edge 7 of the shell part 4 of the fuel tank 1 . The activated carbon filter 9 is likewise connected to the inner region of the compensation tank 5 via a vent line 13 . A further vent line 14 leads through a common region of the wall of the fuel tank 1 with the compensation vessel 5 into the environment. As a result, for example in the event of thermal expansion of the fuel in the chamber 2 , gases can flow through the vent lines 12 into the compensation tank 5 and, from there, through the activated carbon filter 9 into the environment. Furthermore, a base valve 15 which ensures that liquid fuel which has penetrated into the compensation tank 5 is returned to the chamber 2 is arranged in the base region of the compensation tank 5 . On account of the position at which it is arranged, the activated carbon filter 9 in the compensation tank 5 is substantially protected from contact with liquid fuel. FIG. 2 shows a compensation tank 16 for the fuel tank 1 from FIG. 1 . This differs from that shown in FIG. 1 substantially through the fact that a cover 17 of an activated carbon filter 18 arranged inside the compensation tank 16 has connections 19 and is connected to plug connections 20 arranged in the upper region of the wall. Moreover the activated carbon filter 18 has a double-walled housing 21 . FIG. 3 shows a compensation tank 22 which is intended to be secured in a fuel tank (not shown). The compensation tank 22 has two housing parts 23 , 24 which are welded to one another and, in the base region, a molded formation 25 for holding an activated carbon filter 26 . A partition 27 for separating off the activated carbon filter 26 is welded to the base region of the compensation tank 22 . A connection 28 for a vent line leads through the partition 27 . This activated carbon filter 26 too has a cartridge 29 inserted into the molded formation 25 of the compensation tank 22 . FIG. 4 shows a compensation tank 30 which is of particularly simple design and in which an activated carbon filter 31 is secured to the lower of two housing parts 32 , 33 of the compensation tank 30 . Vent lines (not shown) can be connected to the compensation tank 30 and the activated carbon filter 31 .

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CROSS-REFERENCE TO RELATED APPLICATIONS This application is a divisional of U.S. patent application Ser. No. 09/945,456, filed Aug. 30, 2001, now U.S. Pat. No. 6,839,881 which is a divisional of U.S. patent application Ser. No. 09/153,786, filed Sep. 16, 1998, now issued as U.S. Pat. No. 6,374,274, the entire contents of both of which are hereby incorporated herein by reference. APPENDIX A Appendix A is a hard copy printout of the assembly listing consisting of 37 pages, including the title page. This assembly listing is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright rights whatsoever. BACKGROUND The present invention relates to communication networks, and more particularly to networks providing document access to authorized subscribers. One application of information retrieval systems is to provide (by display, printing, or other appropriate means) a collection of documents that is directed to a particular field, so that a particular set of authorized users can select and retrieve a desired portion of the collection. One example of such a system for use in the office of a professional practice has a terminal connected to a memory device having the collection accessible to it (such a collection of video tapes or compact disk ROM being selectively inserted into a compatible drive unit), the terminal controlling the drive unit to access desired portions of particular ones of the media having documents of interest to clients of the practice. Unfortunately, such systems are expensive to provide, set up, and maintain in that all of the costs must be attributed to a single practice. Also, the set up and maintenance frequently requires skills that are not readily available on site. A recent development is the wide use of network communications over the Internet, on which a wide-variety of information is available in massive volumes using local telephone connections and personal computers. The Internet is actually a collection of networks and gateways that use the Transport Control Protocol/Interface Program (TCP/IP) suite of protocols that was developed by the U.S. Department of Defense. The local telephone connections are typically to nearby network server computers (servers) that have connections to other servers. Documents and other information are commonly stored on the Internet using Hyper Text Transfer Protocol (HTTP) in HTML or ASP format in web sites that are implemented at associated servers, the sites being addressed and navigated by using “browser” software of user's computers. The HTTP version 1.1 (outlined in detail in RFC 2068 at http:www.csl.sony.co.jp/cgi-bin/hyperrfc?rfc2068.txt) specifies that upon transmission of each requested element, the browser disconnects from the server. Thus the protocol as defined is “connectionless” in that a single continuous connection is not maintained while browsing a website. A great advantage of this technology is that a large segment of the general population has access to the Internet from home. However, much of that information is of questionable validity, especially when provided free of charge, and the location of relevant information can be a daunting task that involves sifting through great volumes of extraneous records. Consequently, a number of Internet and other computer database services that are restricted to paying subscribers have been developed. These services are commercially viable for business applications; however, they are often excessively expensive and difficult to use in relation to their utility for infrequent personal use. Also, many such services that need to identify users cause authorization information to be transmitted and permanently stored on users' computer hard disk drives. Traditionally Internet servers identify a user by transmitting the requested data along with a special plain text file called a “cookie” which is stored on the user's computer disk memory and can have values written thereto by the server. These cookies typically contain information like the user's name and miscellaneous data that is read back each time the user connects and makes a request, typically for each page or element thereof as indicated above. These cookies are objectionable in that it can contain “viruses” that are known to be harmful to the users' computers. Accordingly, web browsers of the prior art pop up a dialog box that asks whether the user will accept the cookie, further creating an inconvenience to the user. If the user refuses the cookie, then continuity is effectively broken between the browser and the server. Thus there is a need for a reliable source of information that is relevant to clients of professional practices, that is easily accessed and selected by authorized users, that monitors or tracks user access sessions without requiring users to accept cookies, and that is inexpensive to set up and maintain without requiring high levels of specialized skill by employees of particular practices having clients that are authorized users. SUMMARY The present invention meets this need by providing a network database system wherein clients of subscribing entities are authorized network access to reliable documents that are identified by each entity as being relevant to clients of that entity. Features that can be included in the system are customization of the documents to reflect sourcing by particular subscribers, automated formatting of the documents for storing in a network database, client access facilitated by subscriber-maintained databases, and the avoidance of cookies remaining on clients' computer hard drives following document access. It will be understood that while the term “cookie” can include transmitted and stored codes that do not remain following network access and is therefore not considered harmful, as used herein the term is exclusive of transmitted access data that does not remain stored in the client's computer following termination of network access. DRAWINGS These and other features, aspects, and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: FIG. 1 is a plan view of a database system according to the present invention being connected to a computer database; FIG. 2 is a flow chart for a document conversion macro of the system of FIG. 1 ; FIG. 3 is a flow chart for an index preparation portion of the macro of FIG. 2 FIG. 4 is a flow chart for an convert document portion of the macro of FIG. 2 ; FIG. 5 is a navigation path diagram for a subscriber entity portion of the system of FIG. 1 ; and FIG. 6 is a navigation path diagram for a client network access to the system of FIG. 1 . DESCRIPTION The present invention is directed to a document conversion and network database system that is particularly effective in providing relevant document data to authorized clients of subscriber entities. With reference to FIGS. 1-6 of the drawings, a network database system 10 includes a primary computer 12 for receiving and processing data from a provider 13 , a subscriber computer 14 , and a client computer 16 , each of the computers 12 , 14 , and 16 being connectable to a distributed computer network 18 . In an exemplary implementation, the computer network 18 includes a multiplicity of communication lines 20 and a plurality of server computers 22 . One such server, designated 22 A, is a primary server that is set up in a conventional manner for directing communications on the network 18 and having additional features in accordance with the present invention that are described below. Optionally, the primary server 22 A is principally associated with the primary computer 12 (by a local telephone connection); moreover, the primary computer 12 can be integrated with the primary server 22 A. Another server, designated 22 B, communicates with the subscriber computer 14 , and a further server, designated 22 C, communicates with the client computer 16 . It will be understood that a single server may communicate with more than one of the computers 12 , 14 , and 16 . Further, it is contemplated that the system includes a plurality of the subscriber computers 14 , multiple counterparts of the client computers 16 for each of the subscriber computers 14 and, possibly, a plurality of the primary computers 12 . In the exemplary implementation described herein, the communication network 18 is the Internet, with at least some of the communication lines 20 being conventional telephone utility lines, each computer having a suitable modem or digital port (not shown) for interfacing with the telephone utility lines. As used herein, each of the servers 22 other than the primary server 22 A is considered to be a part of a composite network, designated 18 ′. A principal feature of the present invention is that the primary computer 12 is implemented for automatically customizing selected documents of the provider to identify the subscriber, and optionally the client, and reformatting the selected documents to facilitate navigation therein by the subscriber's clients. The clients selectively access and navigate the documents using communications between the client computer 16 and the client server 22 C. The primary computer 12 includes a CDROM drive 24 for receiving and inputting source disks 25 that may be periodically received from the provider 13 . The computer 12 may also include a high-density disk drive 26 for writing processed counterparts of the received data on output disks 27 for delivery to the primary server 22 A. It will be understood that the CDROM drive 24 and the high-density drive 26 can be a single device, and further that the processed data can be transmitted to the primary server 22 A over the network 18 instead of being delivered on the high-density disks. A suitable primary server 22 A can be implemented with the server computer 22 running WINDOWS NT 4.0, MICROSOFT INTERNET INFORMATION server 4.0, MICROSOFT INDEX server, MICROSOFT SITE-SERVER EXPRESS, MICROSOFT ACTIVE SERVER PAGES, MICROSOFT SQL SERVER 6.5, and MICROSOFT TRANSACTION SERVER that are commercially available programs of Microsoft Corp. of Redmond, Wash., the uppercase terms being believed to be respective trademarks of Microsoft. According to the present invention, the server 22 A is further programmed for authorizing and tracking client access as described below in connection with a subscriber and client database that can be implemented in the above-identified SQL Server program. Document Conversion The source disk 25 preferably contains the data from the provider 13 in a plurality of document files, one or more index files, and one or more map files, illustrations, the map files defining links to related documents and images. In an exemplary implementation, the various files are stored as compressed text files in American Standard for Information Interchange (ASCII) format. Typically, certain text is delimited with special codes, such as by being enclosed in brackets, as “[ . . . ]”. Preferably, the text files have imbedded tags for delimiting titles, subtitles, sections, headers, footers, etc. However, HTML tags are appropriately locatable for aesthetically formatting the documents and facilitating navigation thereof based on the document structure alone, without reliance on imbedded tags being in the raw ASCII files. For example, titles and subtitles may be identified by having a length of only one line. As shown in FIG. 2 , a document conversion process 50 is operable when the source disk 25 is mounted in the CD drive 24 . The process includes a conventional decompress step 52 wherein compressed file archives of the provider 13 on the disk 25 are decompressed and each of the resulting files is copied as ASCII text in a suitable hard disk memory working directory 53 of the primary computer 12 . Next, a suitable word processor program is entered in a start word process step 54 and a conversion macro 56 is invoked for processing the source text as described herein. Suitable word processor programs include Microsoft Word 7.0 and MAC WORD, as appropriate for suitable IBM-compatible and MACINTOSH implementations of the primary computer 12 , each program being available from Microsoft Corp., MACINTOSH being believed to be a trademark of Apple Computer Corp. In each of these implementations, the conversion macro 56 is appropriately coded in VISUAL BASIC, also available from Microsoft Corp. In the conversion macro 56 , the working directory 53 as well as a target directory are determined in an initialize step 58 , and linkmap and docmap files therein are opened in an open map step 60 . In the initialize step 58 , one of several possible modules of the files is selectable according to available categories of the information. For example in the case of medical documents, exemplary categories are Adult Health, Pediatric Health, Behavioral Health, Women's Health, etc. as further enumerated in the above-referenced listing of Appendix A. The working directory can be a particular subdirectory having the selected category of documents. Next, a file is read from the top of the directory 53 in a read first file step 62 , and a loop 63 is entered wherein a test index step 64 is performed. This test is firstly on the filename main part for bypassing signon and menu files, for example, and secondly on the extension, also bypassing “*.art” artholder files, the test branching to a prepare index step 66 that is described below in connection with FIG. 3 if the extension is “.idx”. If not, control advances to test article step 68 that for normal articles and similar files such as credits and menus branches to a convert article step 70 that is described below in connection with FIG. 4 . Otherwise in each case of bypassing, the macro advances to a read next file step 72 , followed by a test done step 74 whereby the loop 63 is repeated unless there was no next file, in which the macro 56 ends, completing the process 50 . As shown in FIG. 3 , the prepare index step 66 includes a strip step 76 for removing non-index lines from the current (index) file. A variable η is set to “A” in a set topic pointer step 78 , whereupon a loop 80 is entered in which a get section step 82 finds lines that begin with the letter η, with allowance for the absence of topics having that identification, and further allowance for the topic η having subheadings. Next, in a convert links step 84 , index links are converted to HTML links, and the section η is replaced in an insert section step 86 . Predefined top and bottom content is then added to the file in an add boilerplate step 88 , that content being next modified (by specifying a subindex name, etc.) to be consistent with the selected module in a specialize boilerplate step 90 , after which the current index portion is saved in a save subindex step 92 . The topic letter η is then incremented in an increment pointer step 94 , and a test loop step 96 is performed for repeating the loop 88 until done, in which case control is returned to the main portion of the macro 56 . As shown in FIG. 4 , the convert article step 70 first finds and replaces embedded tags of the current raw article file with corresponding HTML commented tags in a convert tags step 98 . Text that is delimited with special characters is located, and corresponding HTML delimeters are substituted therefor in a special text step 100 . Particularly, bolded text in the raw ASCII files is delimited by brackets (“ . . . [bolded text] . . . ”), being changed by the special text step 100 to “ . . . <b>bolded text</b> . . . ”. A window title and a displayed article title are created in a create title step 102 that also adds top and bottom HTML tags to the file. Unused header information is then hidden by comment codes, and delimited with appropriate tags in a hide header step 104 . Typically, the raw ASCII file has a footer containing a copyright notice, there being a need for improving the form and content of the notice. Accordingly, the footer/copyright information is segregated with lines and italics being added in a convert footer step 106 . Also, if there are sets of tags delimiting reformatted text that should not be altered (such as lists, menus and tables), tags delimiting such text are changed to corresponding HTML tags in a convert preformat step 108 . For example “<!--/btable--> . . . table text . . . <!--/btable-->” is changed to “<pre> . . . </pre>”. Next, a document anchor step 110 establishes a document target name at the top of the file in HTML format, and extracts external target articles and artwork using the linkmap and docmap files, and imbeds corresponding HTML links. Following the document anchor step 110 , a section links step 112 selects section headings and adds copies thereof at the top of the article, the copies being hot-linked into the article body. The section links step 112 makes use of imbedded tags (if present) and structural characteristics of the raw ASCII file to identify the section headings. Next, a paragraphs step 114 converts imbedded paragraph tags to HTML paragraph tags. In the case of indented paragraphs, that text is delimited by “<bodyquote> . . . indented text . . . </bodyquote>” tags. Simple bulleted lists are then converted from reformatted text into properly formatted HTML lists in a make lists step 116 . More complex lists are also reformatted, if feasible; otherwise they are left as reformatted text. Finally, predefined top and bottom content is then added to the file in an add boilerplate step 118 , for providing a consistent appearance in all article files. That content is next modified in a specialized boilerplate step 120 using predefined markers having the actual module name, etc. as in the above-described specialize boilerplate step 90 of FIG. 3 . Upon completion of the conversion macro 56 , the document and index files, stored in HTML/ASP format are transmitted by any suitable means to the primary server 22 A. As an alternative to using the high-density disk 27 as described above, the files can be uploaded by transmission over the network 18 . Subscriber Navigation In the exemplary Internet implementation of the system 10 , the primary server 22 A has a default web page that is addressable from the subscriber computer 14 and any of the client computers 16 . As shown in FIG. 5 , a subscriber navigation path 130 permits a subscriber to set up a practice-specific home page using a new site selection option 132 from the default page, designated 134 . In a practitioner registration process, after appropriate information concerning the site is entered using a series of screens, a username and [and] password for the site is generated at the primary server 22 A, and a virtual website is created as described below. As indicated in FIG. 5 , this information is not immediately available to the subscriber, being subsequently e-mailed (following verification of financial arrangements if desired), the primary server 22 A being implemented in a conventional manner for communicating the username and password to the subscriber computer 14 . Alternatively, the subscriber's username and password can be passed over the network 18 to be displayed on the subscriber computer 14 and saved by the subscriber. The subscriber navigation path 130 also includes a practitioner login path 136 that is password protected according to the present invention. Once the subscriber has transmitted the username and password to the primary server 22 A, the server transmits corresponding codes directed to a username and password header portion of the web browser being run in the subscriber computer. Thus in subsequent browser requests directed to the family of web page locations, the same username and password is automatically passed to the server 22 A as a part of the request. This is an important feature of the present invention that avoids the risks and inconvenience of the subscriber computer 14 having to accept cookies from the server 22 A, which cookies might possibly contain harmful viruses. Appropriate coding for passing the username and password into the appropriate header field of the subscriber's or client's web browser is included in the ODBC program module of the primary server 22 A, the details of such code being within the skill of the web-server programming art. Following successful login, control passes to an administration page 138 from which the subscriber can generate and maintain client data/statistics using a stats window 140 , the client data being retained by the primary server 22 A in the above-identified SQL server. The subscriber can also authorize new users in an authorize window 142 , or amend the previously entered site data in an information window 144 . Additionally, the subscriber can access the above-described converted documents from a practitioner home page 146 , from which an index window 148 facilitates identification of sought-for information. A new and completely different virtual website is created for each practitioner of the subscriber that completes the practitioner registration process. Thus another important feature of the present invention is that although the registration process of the new site path 132 process requires only five to ten minutes to complete, the resulting practice-specific website appears to have required hours of highly skilled labor to produce, just for the practitioner's clients. The practitioners may efficiently promote themselves with these websites, extending the client educational materials of the converted documents to the clients with very little effort. Client Navigation As shown in FIG. 6 , clients of any of the subscribers can also access the default web page 134 from a client computer 16 as described above in connection with FIG. 5 . As shown in FIG. 6 , a client navigation path 150 permits a client to register using a new client selection option 152 from the default page 134 . After appropriate information concerning the client is entered using a series of screens, a username and password for the client is generated at the primary server 22 A. The information required from the client can include last name, first name, middle initial, mailing address, telephone number, a personal password, and an e-mail address. Of course some of this information can be omitted, particularly if it has already been provided to the SQL client database, a minimal requirement being that there be sufficient information transmitted from the client to distinguish from other clients. As indicated in FIG. 5 , the username and password information is not immediately available to the client as described above in connection with FIG. 5 , being subsequently e-mailed (with instructions for using the site). It will be understood that the subscriber can communicate the subscriber's username or any other predetermined designation given to the patient for permitting the client to complete the registration process, which designation can serve as temporary authorization pending granting of the patient's username and password. Also, the client's permanent password can be either chosen by the client or generated by the server 22 A. Once registered, patients have access from the default page 134 and a client login window 154 to the subscriber's home page 146 and the index page 148 . Most preferably, the initial client authorization is unique to each practitioner of the subscriber, each of the practitioner virtual home pages having a respective address that is terminated by the corresponding authorization term, whereby the first screen that the client sees is his practitioner's virtual home page. This page then links to the document modules that the practitioner originally selected during the practitioner registration process. In a preferred form, each client education article begins as follows: “Welcome, <client's first name> <client's last name> to [systemowner].net. This client education material has been provided to you by <practitioner's practice name>.” of course, many variations of the above may be appropriate. Anything that is stored in the practitioner/client database(s) can be displayed on the document pages, so that they can [br] be personalized messages. Document Compilation The converted documents are dynamically compiled in a process that first reads the header field “WWW-Authenticate” for the username, that field reading “WWW-Authenticate username: password . . . ” An exemplary form of the corresponding record of the SQL database reads: Username|firstname|lastname|mi|lastlogin date|etc. A suitable select statement for extracting the client's name is: Select “fname” “mi” “lname” from table where username=“X”. An exemplary HTML coding for each web-page is: Welcome <% fname %> <% lname %> to Ssytemowner.net This web-site has been provided by <% practicename %> Here is the article text . . . . . . . . . . . . . text end. Basically, the primary server 22 A looks at each page before sending it out and replaces the placeholders or variables with the corresponding information from the database table. Any fields of the database can be inserted into the documents. The pre-processed pages are then sent to the client's browser to complete each of the client's requests. Suitable program code for directing this dynamic compilation is provided in the SMTP program module of the primary server 22 A, the details of such code being within the skill of the web-server programming art. Although the present invention has been described in considerable detail with reference to certain preferred versions thereof, other versions are possible. Therefore, the spirit and scope of the appended claims should not necessarily be limited to the description of the preferred versions contained herein.

4y

CROSS REFERENCE TO RELATED APPLICATION This is a continuation-in-part of U.S. patent application Ser. No. 405,456, filed Aug. 5, 1982 now U.S. Pat. No. 4,495,175. BACKGROUND OF THE INVENTION 1. Field of the Invention: This invention relates to and has among its objects the provision of novel methods for the preparation of highly-purified human Factor VIII:C and of a novel procoagulant material having substantially less carbohydrate than native human Factor VIII:C. 2. Description of the Prior Art: It is known that the clotting of human blood is a complicated process, involving a series of reactions mediated by 13 different factors. It also is well known that a cause of hemophilia is the inability of the afflicted individual to synthesize one of these factors, known variously as antihemophilic factor, AHF, AHG, Factor VIII or Factor VIII C, in amounts sufficient to support adequate clotting. Dried preparations of AHF concentrate are sold commercially for administration to hemophiliacs for treatment of bleeding or in advance of surgery. The AHF concentrate is obtained from plasma from human donors, through the use of known techniques. The usual commercial AHF preparation is not pure Factor VIII:C. Rather, it is an AHF-enriched fraction obtained from plasma. It is desirable that the AHF concentrate be as pure as possible, but further improvements in purity through modification of the procedure for isolating AHF from plasma have not been practically feasible due to the difficulty of separating plasma components. AHF is quite difficult to separate and purify because of its low content in the plasma and the instability of its activity. The known AHF concentrates are prepared from fraction I separated from plasma by means of Cohn's ethanol fractionation method or from the cryoprecipitate obtained by freezing a plasma and then thawing it at a low temperature. However, they are all crude products of low purity and contain a large quantity of fibrinogen. As mentioned above, the AHF concentrates obtained by the prior art processes discussed above are of relatively low specific activity, namely about one unit or less of AHF activity per milligram (mg) of protein, one of the undesirable impurities being denatured AHF. U.S. Pat. Nos. 4,289,691 and 4,302,445 disclose processes for preparing AHF preparations having a specific activity of AHF activity of 1-3 units per mg of protein, and U.S. Pat. No. 4,294,826 describes a method for preparing human AHF having a specific activity of about 1-10 units of AHF activity per mg. AHF, or Factor VIII, is now known, however, to exist as a complex of several different protein subunits with several different functions. The exact nature of the complex (i.e. whether the subunits are separate molecules or parts of one molecule and which functions are associated with which subunits) is not yet fully understood. However, it is now known that procoagulant activity, or AHF, or antihemophiliac activity is associated with one subunit, termed Factor VIII:C. Von Willebrand activity, measured as platelet aggregation activity, is associated with a subunit termed Factor VIII:vWF or Factor VIII R:Ag. Another functional subunit is termed Factor VIII C:Ag since this subunit contains the F VIII antigen. Several investigators have tried to separate F. VIII:C from other active Factor VIII components, as disclosed in Fulcher et al, P.N.A.S., 79:1648-152 and the related patent, U.S. Pat. No. 4,361,509, cited in the copending application. Carbohydrate side chains have been studies in multimeric Factor VII:C/vWF to determine their role in platelet aggregation. In addition, alteration of these side chains is known to affect plasma clearance. These side chains are thought to terminate in sialic acid residues linked to galactosyl residues. In mammals, a specific hepatic receptor recognizes terminal galactosyl residues on glycoproteins which have been treated to remove sialic acid, so that these asialoglycoproteins are cleared rapidly by the liver. Sodetz et al, J. Biol. Chem., 252:5538-46, (1977) disclose the neuramidase treatment of human F. VIII:C/vWF purified from human AHF concentrates. They found that upon removal of sialic acid, vW (platelet aggregating) activity is markedly reduced, while procoagulant activity remains constant. The circulating half-life of the treated protein in rabbits goes from about 240 min. to about 5 min. Sodetz et al, J. Biol. Chem., 253:7202-7206, (1978) report treatment of F. VIII:vWF with neuramidase as in the previous experiment, followed by incubation with galactosidase to remove 62% of the galactose. Procoagulant activity was not decreased, but VW activity dropped markedly. From these studies it was concluded that vWF activity is dependent on terminal sialic acid residues, the penultimate galactose residues, and protein structure. Gralnick et al, P.N.A.S., 80:2771-2774, (1983) treated F. VIII/vWF with neuramidase beta galactosidase, and galactose oxidase. They reported, consistently with Sodetz et al, that this treatment reduced vWF activity. It was suggested that the next-to-terminal galactose is responsible for maintaining the largest multimers of the factor VIII/vWF factor protein. Treatment of intact protein with these enzymes did not produce a lowering of vWF or procoagulant activity, but treatment of the asialo factor VIII/vWF protein with beta galactosidase resulted in a time-dependent decrease of vW factor activity. This was correlated with loss of the largest multimeric subunits and vW activity. SUMMARY OF THE INVENTION The preparations produced by the method of the invention have about 4000-8000 units of AHF (procoagulant) activity per mg of protein (one unit of activity is that found in 1 ml of normal human plasma). The product appears as homogeneous and having a molecular weight of about 95,000 on SDS/PAGE. The present invention is directed to essentially pure human F. VIII:C, free of F. VIII:vWF and other procoagulant activities, and which is substantially reduced in carbohydrate content. The invention is further directed to such homogeneous F. VIII:C, free of F. VIII:vWF and other procoagulant activities having less than 50% of the carbohydrate of naturally occurring human F. VIII:C. This material retains essentially all of its procoagulant activity, and retains significant survival in vivo. Its molecular weight on SDS/PAGE is approximately 95,000, compared to 100,000 for the highly purified human F. VIII:C. This is consistent with published reports that AHF (including vWF) generally contains about 10%-15% carbohydrate. The present material, as prepared, therefore contained about 7.5% to 5% carbohydrate. It is contemplated that deglycosylated material similar to the present invention can be prepared by genetic engineering methods involving expression of the human F. VIII:C gene in systems wherein no carbohydrate is added to synthesized protein. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1-4 are depictions of the chromatographic separations of AHF (Factor VIII C) in the steps of the method of the invention; FIG. 5 is a depiction of the results of the SDS polyacrylamide gel electrophoresis (Laemmli, Nature, 277, 680-685, 1970, incorporated herein by reference) in a 6% gel on preparations produced in accordance with the invention; FIG. 6 is a photographic representation of PAS-stained F. VIII:C treated with various glycosidases. FIG. 7 is a photograph showing SDS polyacrylamide gel electrophoresis of deglycosylated (glycosidase-treated) F. VIII:C; and FIG. 8 is a chart showing in vivo survival times of the deglycosylated (glycosidase-treated) F. VIII:C. DESCRIPTION OF THE PREFERRED EMBODIMENTS The starting material of the present invention is a concentrate of AHF obtained from human blood plasma, such as a commercially available AHF preparation. The concentrate of AHF is subjected to a separation on the basis of Stokes' radius wherein proteins of lower molecular weight are separated from AHF, which exhibits an apparently high Stokes' radius. The above separation may be accomplished in a variety of ways such as subjecting the AHF concentrate to gel permeation chromatography on cross-linked agarose (such as Biogel A-15 m or Sepharose CL-4B) or cross-linked polyacrylamide or to a controlled pore size glass bead treatment or to sucrose density gradient ultrafiltration. All of the above techniques are well-known in the art. Preferably, the AHF concentrate is subjected to gel permeation chromatography on, for example, cross-linked agarose or polyacrylamide. After equilibration on the chromatographic medium, AHF is eluted with a buffered salt solution having an ionic strength of about 0.1-0.4 and a pH of about 6.0-7.5. The fractions containing the eluted AHF from above are pooled and the pool is concentrated by techniques known in the art such as precipitation with ammonium sulfate, sodium sulfate, etc., by diafiltration, by PEG addition, or the like. For example, the AHF pool may be treated with ammonium sulfate (30-40%, weight/volume) to precipitate AHF. The AHF, after concentration, is dissolved or equilibrated in an aqueous salt buffer of pH about 6.0-7.5 and ionic strength about 0.1-0.4. If a salt such as ammonium sulfate was added in the course of concentration of the AHF pool, such salt is removed prior to the next step by known techniques such as dialysis, diafiltration, and the like. Next, the AHF concentrate is treated to change the effective Stokes' radius of the AHF molecule to an apparently low value. To this end one may add a source of divalent cations such as calcium or magnesium wherein about 5-10 parts by volume of protein solution with 1 part of a solution about 1-3M in divalent cation is employed per part by volume of AHF concentrate. The above mentioned reduction in Stokes' radius can also be accomplished by attaining a high ionic strength in solutions of AHF (e.g. about 1-4M with sodium chloride) or the incubation of AHF with about 0.01-0.001 parts of thrombin per part of AHF concentrate (in units) (Leon W. Hoyer, Hemophilia and Hemostasis, "The Factor VIII Complex:Structure & Function", Alan R. Liss, Inc., pg. 7, [1981]). Following reduction in Stokes' radius of the AHF molecule, the AHF concentrate is treated to remove divalent cations by known procedures such as dialysis or diafiltration and then is subjected to a separation on the basis of Stokes' radius by any of the means described above. Preferably, the AHF concentrate is subjected to gel permeation chromatography on cross-linked agarose or polyacrylamide, chromatographic medium equilibrated and eluted with a buffered salt solution having an ionic strength of about 0.1-0.4 and a pH of about 6.0-7.5. The eluted fractions containing AHF activity are pooled and optionally concentrated by reduction of water content. To this end the pooled fractions may be concentrated by techniques known in the art such as dialysis, diafiltration, etc. The fractions may be immersed in, for example, solid PEG 20,000 in order to extract water from the solution within a dialysis container. The concentrated material is treated to remove divalent cations by dialysis, diafiltration, or the like, against a buffer at a pH of about 6.0-7.5. Following the above concentration steps, the fraction containing AHF activity is subjected to chromatography on an anion exchange medium such as quaternary aminoethyl (QAE) cellulose, diethylaminoethyl (DEAE) cellulose, or similar anion exchanger. The chromatographic medium is washed with a buffered aqueous solution having an ionic strength sufficient to remove unbound protein but not AHF, i.e., 0-0.2 (0-0.2M sodium chloride, and the like). Finally the chromatographic medium is eluted with an aqueous solution having an ionic strength sufficient to elute AHF, i.e., about 0.2-0.6 (e.g. 0.2-0.6M sodium chloride, and the like) to give fractions containing AHF, which are then pooled. The pooled fractions from the above chromatography contain Factor VIII:C having a specific activity of at least about 4000 AHF units per mg of protein and represent a substantially homogeneous preparation on ion exchange chromatography on QAE cellulose and sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (Laemmli). Such a product has heretofor, not been described, disclosed, or suggested by the prior art. The pooled fractions constitute Factor VIII:C purified at least about 350,000-fold over that found in plasma; it may be sterile filtered and lyophilized. The pooled fractions from above may optionally be subjected to HPLC under non-denaturing conditions. For this purpose conventional HPLC apparatus may be employed and the elution of AHF accomplished in a standard manner based on Stokes' radius. The fractions containing Factor VIII:C are pooled and represent a 10% yield of product; the Factor VIII:C has a specific activity of at least about 4,000 AHF units per mg of protein. The fraction may be sterile filtered and treated to reduce its water content either by ultrafiltration, lyophilization or combinations thereof. The Factor VIII:C preparation exhibits homogeneity by HPLC and SDS polyacrylamide gel electrophoresis (PAGE) (Laemmli). Thus, the Factor VIII:C preparation is essentially homogeneous and essentially free (i.e., contains less than about 1% combined of non-AHF proteins) of Factors II, VII, IX, X, fibrinogen, albumin, fibronectin, von Willebrand factor, and has essentially no activity in a non-activated partial thromboplastin time assay indicating that the purified protein essentially does not contain activated clotting factors circumventing the AHF dependent step in the clotting cascade. The Factor VIII:C preparations of the invention, in addition to having the ability to correct the clotting defect in hemophilic plasma, also exhibit the following characteristics: (a) The biological activity is increased, and the putative polypeptide chain is altered, following treatment with thrombin. The purified protein can be activated by treatment of thrombin to give 4-20 fold increase in AHF activity. (b) The biological activity can be blocked by the inhibitors against AHF which are found in certain patients with classical hemophilia. When mixed with a several fold excess (unit:unit) of AHF inhibitor, between 95 and 99% of the measurable AHF activity can be abolished. (c) The purified native Factor VIII:C, after reduction and SDS PAGE, appears a single polypeptide chain with an apparent molecular weight of about 100,000. Following incubation with thrombin, virtually all of the 100,000 polypeptide disappears and is replaced by bands with molecular weights of 75,000 and 26,000. (d) The purified Factor VIII:C appears to be substantially free from significant protease activity, and from essentially all other plasma proteins. (e) The purified Factor VIII:C is substantially free from AHF antigen (Factor VIII:C Ag). The ratio of AHF:AHF antigen is usually about 50:1 or greater, usually within the range of about 50:1-150:1. The amino acid composition of the human AHF preparation of the invention is given in Table 1. TABLE 1______________________________________Human Factor VIII: C Amino Acid CompositionResidue % Total Amino Acids______________________________________Cysteic Acid 2.62Aspartic Acid 9.6Threonine 3.65Serine 5.49Glutamic Acid 13.55Glycine 10.5Alanine 7.73Methionine 2.44Isoleucine 2.67Leucine 11.65Tyrosine 4.78Phenylalanine 5.32Histidine 3.01Lysine 4.29Arginine 8.90Valine 3.75Cysteic Acid 2.62______________________________________ Tryptophan and Proline are not detected by the system the system used. Cysteic acid is estimated from a performic acid oxidized sample. Materials and Methods Materials. Parts and percentages are by weight unless otherwise specified. Concentrates obtained from human plasma cryoprecipitate were provided by Cutter Laboratories (Berkeley, Calif.) for purification of factor VIII. Hemophilic plasma was purchased from George King Bio-Medical, Inc. (Overland Park, Kans.). Radiolabeled Na 125 I was obtained from New England Nuclear (Boston, Mass.), and radioiodination of factor VIII:C was performed using Enzymobeads™ which were purchased from Bio-Rad Laboratories (Richmond, Calif.). Human thrombin (4000 units/mg) and heparin were purchased from Sigma Chemical Co. (St. Louis, Mo.). Sephacryl S-300 and S-400 were purchased from Pharmacia Fine Chemicals (Piscataway, N.J.). The rabbits used for infusions were New Zealand Whites obtained from Hazelton Dutchland (Denver, Pa.) and weighed 2.5 to 4 kg. Neuraminidase (Type VIII, 19 units/mg) was obtained from Sigma Chemical Co. (St. Louis, Mo.). Beta-galactosidase from E. coli (300 units/mg), alpha-mannosidase from jack bean (10 units/mg), and beta-N-acetyl-D-glucosaminidase from beef kidney (4 units/mg) were obtained from Boehringer Mannheim (Indianapolis, Ind.). Endoglycosidase D (endo-beta-N-acetylglucosaminidase D from D. pneumoniae, 20 units/mg) and Endoglycosidase H (endo-beta-N-acetylglucosaminidase H from Streptomyces plicatus, 31 units/mg) were generous gifts from Miles Laboratories, Inc. (Elkhart, Ind.). These glycosidases were essentially free of contaminating protease activity according to the manufacturer's specifications and had no effect on the electrophoretic mobility of bovine serum albumin after prolonged incubation at relevant concentrations. Radioiodination of factor VIII. Factor VIII:C (10 μg in 25 μl of imidazole-saline buffer) was radiolabeled with 1 mCi 125 I using the Enzymobeads™ radioiodination reagent. Unreacted 125 I was removed by gel filtration using Sephadex G-25. Bovine serum albumin (200 μg/ml) was added as a carrier to the labeled protein which was then extensively dialyzed against imidazole-saline buffer. When analyzed by NaDodSO 4 polyacrylamide gel electrophoresis and autoradiography, the iodinated factor VIII:C appeared as a single band of M r 100,000, indicating that it was not degraded. The specific activity of 125 I-factor VIII:C was approximately 10 6 cpm/μg and was greater than 90% acid insoluble. Glycosidase digestions. As referred to in Example III, all reaction mixtures contained purified factor VII:C (200 μg/ml) or 125 I-factor VIII:C (6-13×10 6 cpm) in imidazole buffered saline, those with labeled protein also including 200 μg/ml BSA in the buffer as a carrier. Reactions involving exoglycosidases contained neuraminidase (0.1 unit/ml, beta-galactosidase (0.1 unit/ml), alpha-mannosidase (0.05 units/ml) and N-acetyl glucosaminidase (0.1 unit/ml). Reactions with the exo- and endoglycosidases contained the above enzymes plus endoglycosidase D (0.02 units/ml) and endoglycosidase H (0.02 units/ml). Reaction volumes were 100 μl and all reactions were incubated at 37° C. for 18-22 hours. Glycosidase-treated, 125 I-factor VIII was chromatographed on Sephacryl S-300 (1×20 cm), equilibrated in imidazole saline with 0.2% sodium azide and 500 μg/ml BSA and eluted in this buffer. Fractions (300 μl) were collected and monitored for radioactivity, and peak fraction(s) were dialyzed extensively into imidazole-saline prior to infusion into rabbits. Thrombin-potentiated Activation. Native and sugar-depleted factor VIII:C were assayed for thrombin-potentiated activation of clotting activity. Factor VIII:C was incubated with thrombin (10 units/ml) at 23° C. for 1 minute, and assayed using the one-stage assay. The decay of activity following activation was monitored from later time points (5 to 30 minutes) taken from similar reaction mixtures. Clotting Assays. AHF was measured by a one-stage clotting assay, using as substrate plasma from a patient with severe AHF deficiency (less than 1% AHF), and using a Fibrometer to determine the clotting time. One unit of AHF was defined as the amount in 1 ml of pooled normal human plasma. (Langdell et al, J. Lab. Clin. Med., 41, 637-644, 1953. Protein estimations were made using a Gilford 250 spectrophotometer. All samples were read at 280 nm and 320 nm, and the absorbance corrected for light scattering by the following formula. A.sub.280 corrected =A.sub.280 uncorrected -1.7 (A.sub.320) A mean A 280 corrected 1% of 10.0 was assumed for calculations of specific activity. Polyacrylamide gel electrophoresis. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed according to O'Farrell employing a 4.5% stacking gel with an 8% or 6% separating gel. Electrophoresis was at 25 mA for four hours. Polyacrylamide gel electrophoresis under nondenaturing conditions employed a 5% gel and 25 mM Tris and 192 mM glycine, pH 8.3. Electrophoresis was at 250 volts for three hours at 4° C. (O'Farrell, J. Biol. Chem., 250, 4007-4012 1975). Gels were stained for protein using silver nitrate and for carbohydrate using periodic acid Schiffs reagent. Protein was eluted from the unstained gel by slicing at 5 mm intervals and adding each slice to 0.3 ml of 50 mM Tris-hydrochloride, pH 7.0, 150 mM NaCl and 200 microgram/ml ovalbumin. The mixture was incubated at 4° C. for 2-3 hours and assayed for AHF procoagulant activity as described above. Gels stained with PAS were scanned with a Quick Scan Jr. scanning densitometer (Helena Laboratories, Beaumont, Tex.) at 565 nm. Factor VIII:C Ag Assay. The procedure of Reisner et al was followed. The antibody was kindly provided by Howard Reisner. (Reisner et al, Thromb. Research, 14, 135-239, 1979). Inhibition of AHF Activity. This was measured by mixing 1 volume of sample containing AHF with an equal volume of human plasma containing inhibitor to AHF. The concentration of inhibitor was always several fold in excess of the AHF concentration. After incubation for the time indicated, the residual AHF was assayed. Thrombin Activation of AHF. (Switzer et al, J. Biol. Chem., 255, 10606-10611, 1980). von Willebrand Protein Assay. (Voller et al, Bull. World Health Organ., 53, 55-63, 1976). Silver Stain. (Merrill et al, Science, 211, 1437-1438, 1980). EXAMPLE I Purification of AHF The starting material was AHF therapeutic concentrate (Koate®) from Cutter Laboratories, Inc. (1) Referring to FIG. 1 gel permeation chromatography was carried out on Biogel A-15 m (Bio Rad Laboratories, 100-200 mesh) in a column 2.6×90 cm with CaCl 2 (1 mM), sodium citrate (5 mM), 0.135M NaCl, 5% dextrose, 0.1% sodium azide at pH 7.35 and at ambient temperature as the eluant. The fractions containing the highest concentrations of AHF were pooled (10) and concentrated by precipitation with 40% w/v ammonium sulfate. In preparation for the next step, the precipitate was dissolved in 50 mM imidazole buffer at pH 7.0 containing 150 mM NaCl and dialyzed to remove residual ammonium sulfate. (2) The dialyzed sample from 1 above was made 250 mM in CaCl 2 by mixing 1 volume of 2.5M CaCl 2 with 9 volumes of protein solution. The sample was then chromatographed on a 2×100 cm glass column of Sepharose 4B-CL previously equilibrated with the same buffer. The elution medium was a 50 mM imidazole buffer at pH 7.0 containing 150 mM NaCl and 0.25M CaCl 2 . Referring to FIG. 2, area 12 represents the fractions containing AHF activity, which were pooled. (3) The AHF pool (12) from the previous step was concentrated by placing the pool in a dialysis bag and immersing the bag in solid PEG-20,000. The concentrated sample was then dialyzed against 50 mM imidazole buffer pH 7.0 and 0.15 molar sodium chloride and was chromatographed on a 2.5×10 cm plastic column of QAE cellulose previously equilibrated with the same buffer. All of the AHF was bound under these conditions. Referring now to FIG. 3, when the unbound protein (16) had been washed through with 0.15M NaCl, a step gradient of 0.20M NaCl in the same buffer was run, an additional peak (18) of protein containing little or no AHF was eluted. Finally, a linear gradient of 180 ml from 0.20-1.0M NaCl was run at 17 ml per hour. An additional peak (20) of protein was eluted, and towards the end of this peak, the AHF activity eluted in a fairly sharp peak (14) starting at around 0.3M NaCl. The protein was pooled according to the AHF activity. Unbound proteins are indicated at 24 in FIG. 5 (SDS polyacrylamide gel electrophoresis [Laemmli] in a 6% gel); protein eluted with 0.2N NaCl is represented at 26; and the peak at 28 was eluted at 0.2M NaCl. The AHF preparation so-produced exhibited homogeneity (30) on SDS polyacrylamide gel electrophoresis (Laemmli) in a 6% gel (FIG. 5). The specific activity of this preparation was about 5,000 units of AHF activity per mg of protein, representing a 350,000 fold purification over source plasma. A 10% overall recovery from the commercial AHF concentrate was realized. (4) The pooled fraction from step (3) was concentrated prior to high performance liquid chromatography (HPLC). HPLC was carried out on a Beckman TSK 4000 l×30 cm column at 40 psi, flow rate of 0.5 ml/minute. The profile is shown in FIG. 4. The AHF eluted coincident with the second peak (44), intermediate between the elution positions of IgM (MW 890,000) and IgG (MW 160,000). The two largest peaks 50 and 52 do not contain AHF activity and represent PEG (50) buffer and a change (52). Peak 54 represents bovine serum albumin (BSA). In FIG. 4, arrows at 46, 48, and 54 represent elution volumes of marker proteins of known molecular weights in parallel runs: 46=IgM (MW 890,000) and 48=IgG (MW 160,000). Highly purified Factor VIII:C, according to the present invention, may also be purified by a modification of the procedure of the inventors as published in P.N.A.S. 72, 7200-7204 (1982). The partially purified factor VIII obtained from Sepharose 4B chromatography in 20 mM imidazole-Cl pH 7.0, 150 mM NaCl, 250 mM CaCl 2 100 mM lysine-chloride and 0.02% sodium azide (as in Step 2 above) may be concentrated 20-fold in an Amicon ultrafiltration cell using a YM 10 membrane at 50 psi. The concentrated sample may then be applied to a 1.5×80 cm column containing Sephacryl S-400 equilibrated in the above buffer. This procedure would replace the QAE cellulose chromatography as the final purification step. Referring to FIG. 5, the AHF pool from step 4 above is essentially homogeneous (32) on SDS PAGE (Laemmli) in a 6% gel. This preparation has a specific activity of about 5000 AHF units per mg of protein representing a purification factor of 350,000 over source plasma. In FIG. 5 the origin for the SDS PAGE is represented at 34 and the ion front at 36. Column 22 represents myosin heavy chain (38) molecular weight 200,000, BSA (40) molecular weight 68,000, and ovalbumin (42) molecular weight 43,000. The above operations and results are summarized in Table 2. TABLE 2__________________________________________________________________________PURIFICATION OF HUMAN AHF Total Total Specific Volume Protein Activity Activity Yield Purification (ml) (mg) (units) (units/mg) (%) (x-fold)__________________________________________________________________________Plasma -- -- -- 0.014 -- 1Koate 250 12,580 11,000 0.87 100 62Biogel A-15 M 22 318 9,469 29.8 86 2,126ammonium sulfatedialysisCa.sup.++ 110ssociation 13.2 6,850 519 62 37,067Sepharose CL-4BdialysisQAE cellulose 29.5 0.28 1,396 4,986 12.7 356,122__________________________________________________________________________ All values represent the average of two preparations. EXAMPLE II Preparation of Deglycosylated F. VIII:C and Electrophoresis with PAS Stain Highly purified F. VIII:C prepared according to Example I was treated with exoglycosidases (which remove carbohydrates from a terminal and to a branch in the COOH chain) and endoglycosidases (which remove carbohydrates proximally of chain branching), as described under Materials and Methods. Removal of carbohydrates was determined by electrophoresis in an 8% denaturing, polyacrylamide gel. After electrophoresis, the gel was stained for carbohydrate using periodic acid - Schiffs reagent (PAS). This staining procedure allows for the determination of relative amounts of carbohydrate in the protein by comparing the intensities of the stain, as determined by scanning densitometry. The untreated F. VIII:C and the exoglycosidase treated F. VIII:C showed similar intensity of staining and similar areas under the scanning densitometer curves. This indicates that very little, (less than 10%) sugar is removed by the exoglycosidase mixture alone. The F. VIII:C plus exo- and endoglycosidases showed significantly diminished staining intensity. The area under the scanning densitometer curve for this material indicated that about 50% of the total carbohydrate was removed from Factor VIII:C when treated with the combination of exo- plus endoglycosidases to produce F. VIII:C having substantially lowered carbohydrate content compared to native F. VIII:C, i.e. "deglycosylated" F. VIII:C. The deglycosylated F. VIII:C consisted of a single polypeptide with an increased rate of mobility on the SDS/PAGE equivalent to a new M r of 95,000, compared to an M r of 100,000 M r for untreated F. VIII:C. The F. VIII:C treated solely with exoglycosidases showed an approximate M r of 97,000. FIG. 6 represents a PAS stained gel showing in lane 1 exo- and endo-glycosylate-treated (deglycosylated) F. VIII:C, in lane 2 untreated F. VIII:C, and in lane 3 exoglycosidase-treated F. VIII:C. Lane 1 shows the decreased PAS stain of the deglycosylated F. VIII:C compared to the material of both lane and lane 3. EXAMPLE III Preparation of Deglycosylated F. VIII:C - Further Electrophoresis with Silver Nitrate Stain Referring now to FIG. 7, F. VIII:C was treated with (1) exoglycosidases and a (2) combination of endoglycosidases and exoglycosidases for 18-24 hours at 37° C. prior to electrophoresis using a 8% separating SDS-polyacrylamide gel as described in Materials and Methods, above. Following electrophoresis, the gel was stained with silver nitrate. The electrophoretic mobility of Factor VIII (lane 2) was increased following treatment with the exoglycosidases (lane 3) resulting in a new M r of 97,000. Treatment with the combination of exoglycosidases and endoglycosidases resulted in a further reduction in size, lane 1, showing an M r of 95,000. The band at 68,000 in lane 1 is bovine serum albumin (BSA) present in the endoglycosidases as a stabilizing agent. Lane 4 represents high molecular weight protein standards; the numbers to the right represent the size of these standards and are expressed as M r ×10 -3 . The Factor VIII:C (Mr 100,000) is cleaved by thrombin into two fragments of M r 75,000 and 26,000. 125 I-labeled Factor VIII was treated with the exoglycosidase cocktail following thrombin cleavage of Factor VIII. The reaction mixtures were subjected to 10% SDS-polyacrylamide gel electrophoresis followed by autoradiography. Factor VIII:C treated with thrombin yielded the M r 75,000 and ˜26,000 polypeptides. After thrombin treatment, the F. VIII:C was treated with the exoglycosidase cocktail. The M r 75,000 polypeptide is not significantly changed in electrophoretic mobility while the M r ˜26,000 polypeptide shows a significant increase in electrophoretic mobility suggesting that this polypeptide is relatively rich in carbohydrate (at least sialic acid) relative to the M r 75,000 polypeptide. Activation by thrombin and quantification of sugar removal are set forth in Table 3. TABLE 3______________________________________ % Sugar Thrombin Remaining % Activity ActivationCondition (±SD) (±SD) (x-fold)______________________________________Factor VIII 100 100 24+Exoglycosidase 87 ± 6 119 ± 24 21+Exo-plus 54 ± 4 91 ± 18 20endoglycosidase______________________________________ The percent sugar remaining indicates the amount of PAS stainable material, following NaDodSo 4 polyacrylamide gel electrophoresis, determined by scanning densitometry. Values represent the average (with standard deviation) of three separate determinations. Percent activity values are the average (with standard deviation) of four separate experiments. Thrombin activation values represent the ratio of units of thrombin-activated factor VIII to units of unactivated factor VIII. While some variability was observed, no significant increase or decrease in clotting activity was observed relative to the untreated Factor VIII. The clotting activity was determined according to the assay set forth above. EXAMPLE V In Vivo Survival of Deglycosylated Factor VIII:C Purified Factor VIII:C was trace labelled with 125 I using lactoperoxidase and glucose oxidase coupled to insoluble beads. The labelled protein was separated from non-covalently bound iodine using gel filtration followed by dialysis. Factor VIII labelled by this procedure retains 5-10% of its clotting activity and migrates in a reduced SDS PAGE in a single polypeptide chain M r 100,000 with the same electrophoretic properties as its unlabelled counterpart. Approximately 50-100 ng of labelled Factor VIII (6-13×10 6 cpm) were injected carefully into the central ear vein of a 2 kg New Zealand white rabbit. Samples of blood were withdrawn after different time intervals, from an indwelling scalp vein needle in the opposite ear. Samples of 1 ml were removed, mixed with 1/100 volume of 40% citrate, and counted in a gamma counter. The amount of labelled protein remaining was plotted against time, in order to determine the rate of clearance of labelled protein. Several samples of plasma from different times after infusion were analyzed by SDS PAGE. The results confirm that the radioactivity continues to be associated covalently with the protein. The results of 3 separate experiments in 2 animals indicate that about 50% of the labelled protein (either native or deglycosylated) disappears with a half time of ˜60 minutes, whereas most of the remainder continues to circulate with a half time of about 4 hours. Although not shown in FIG. 8, we have found that a small fraction of the Factor VIII, perhaps ˜20%, appears to have an even longer half life, in the range of 10-12 hours. A similar infusion experiment was carried out with Factor VIII which was treated for 15 hours with neuraminidase to remove terminal sialic acids. This treatment has been shown to have no effect on the clotting activity of Factor VIII in vitro, and to cause a small increase in the rate of migration of Factor VIII in SDS PAGE. When the desialylated Factor VIII was infused intravenously, about 90% of the activity disappeared from the plasma within 5 minutes of infusion. The remaining 10% remained in circulation with a biological half time of ˜4-5 hours. The results with the desialylated Factor VIII are similar to those seen with many other (but not all) plasma glycoproteins. Removal of the terminal sialic acids results in the very rapid clearance from the plasma of a major fraction of the protein. This effect on clearance time is in contrast to the lack of detectable effect on clotting activity in vitro, as reported earlier. Referring now to FIG. 8, the closed circles indicate the survival of native 125 I-factor VIII:C Open circles indicate the survival of deglycosylated 125 I-factor VIII:C. The lowest line shows survival of neuraminidase-treated F. VIII:C is shown to indicate the rapid clearance of this material, as discussed above. The 100% point was obtained immediately after infusion (<30S) and was in agreement with the calculated value based upon blood volume and dose. The half-life of survival was determined from the linear portion of the curves which followed the initial, rapid clearance phase. Both native highly purified F. VIII:C and the deglycosylated F. VIII:C showed a 2-phase decay curve with a rapid initial phase followed by a slow metabolic decay. Untreated material showed a drop in radioactivity to 60% of initial within 25 minutes; sugar-depleted protein decreased to 40% in 15 minutes. Following the rapid clearance rates, both types of factor VIII proteins were cleared from the circulation at similar rates with a half-life of about 250 minutes (4-5 hours).

4y

CROSS-REFERENCE TO RELATED APPLICATIONS Not applicable. 1. Field of Invention This invention is an improved and more versatile apparatus for cutting roofing shingles. 2. Description of Prior Art Installation of roofing shingles requires many cuts to be made in various directions. Traditional practice calls for use of a hand-held utility-type knife which is slow and inaccurate and potentially dangerous since some types of shingles need multiple passes and considerable force with the knife, which can and does slip, causing injury. Several designs have been proposed for an apparatus to cut shingles, however, these designs are limited in performance in various ways. The underlying problem is that shingles resist being cut, and particularly, cut neatly. This is due to their thickness and toughness and the wide range of workability resulting from the extremes of ambient temperature during which they are installed. In cold weather, shingles are stiff and brittle, resistant to cutting, and tend to crack without careful handling. In hot weather, they become exceedingly soft and pliable and prone to tearing. Also, in hot weather, the asphaltic component of the shingles softens into a semi-melted state and accumulates as a tarry deposit on tools. Under any weather conditions, debris and granules from the surface of the shingles are dislodged in handling and collect within the workings of an apparatus not designed to tolerate them. A shingle cutting apparatus must also take into account that regardless of the design employed a vigorous thrust of the mechanism will be required to effect its operation, again due to the resistance of the shingle being cut. This requirement can be satisfied by proper provision for the use of leverage, however, the apparatus must be configured to remain stable in the face of the forceful stroke by the user. If the apparatus moves or tips in use, it will be inconvenient or dangerous to use. Prior art fails to overcome these difficulties and therefore has not met with practical success. U.S. Pat. No. 5,052,256 to Morrissey and U.S. Pat. No. 4,951,540 to Cross et al disclose designs that perform only one specialized cut on only one type of shingle. Considered analysis indicates that in addition to this limitation these two designs do not allow the user to develop sufficient leverage to operate successfully under the wide range of field conditions previously mentioned. A different apparatus is disclosed in U.S. Pat. No. 5,787,781 to Hile. In the initial stages of my own experimentation, I developed, constructed, and tested a model essentially similar to this and determined that it has several shortcomings. The blade does not consistently maintain tight contact with the edge of the work surface because of lack of sufficient rigidity both of the blade and of the pivot arrangement. A very small amount of distortion in the area of the pivot allows the blade to separate from the edge of the work surface and merely sandwich the shingle between the two instead of cutting it. This phenomenon is exacerbated by the accretion of tarry deposits on the mating surfaces of the blade and the edge of the work surface as well as the accumulation of shingle debris and detached surface granules in these deposits and in the pivot area. Use of a precision bearing as proposed by Hile has a drawback in that it will be vulnerable to damage in the real-world conditions that prevail while roofing is being done. This type of work is frequently carried out under wet conditions; also, the tendency of shingles to generate debris particles and shed granules as previously mentioned will degrade a precision mechanism. Moreover, the need for a complex bearing in this application is questionable, since the motion anticipated is comparatively slow and sporadic and covers something less than a ninety degree arc, whereas a ball or roller bearing would be more appropriately specified in an application having greater or continuous motion and/or higher speed. Hile shows no method of sharpening the stationary cutting edge. As the edge becomes worn, the tendency of the shingle to be sandwiched between the cutting edge and the blade will increase. Another shortcoming of Hile derives from the position of the guide member relative to the shingle. Since the shingle resists being cut, the motion of the blade tends to force the shingle to slide away from the pivot, and therefore, away from the guide member at the beginning of the cutting stroke. This reduces the accuracy of the cut. The Hile apparatus also lacks the ability to make an accurate and repeatable angle cut. Further, there is no provision at all to produce the lengthwise cuts that are necessary for the lowest, or starting course of shingles. Hile proposes the blade to be outside of the footprint outlined by the supporting legs. This may allow the apparatus to tip to the right in response to vigorous force on the handle. In addition, the fact that the handle extends substantially beyond the ends of the legs would tend to cause the opposite, or pivot, end of the apparatus to lift in response to the cutting stroke. Further, the apparent width between the legs of the apparatus would seem to preclude its use on the narrow scaffolding typically used on a roof. SUMMARY In accordance with the present invention, a shingle cutting apparatus comprises a raised work surface with a horizontal fixed blade attached along one side, a moveable and adjustable blade assembly, and a guide fence assembly capable of being fixed at any desired location on the work surface to align a shingle for a cut. OBJECTS AND ADVANTAGES Accordingly, several objects and advantages of my invention are as follows: 1. The triangular design of the moveable blade assembly, the use of a long pivot shaft attached on both ends, and the design of the frame all provide superior rigidity and keep the moveable and fixed blades in tight contact with each other resulting in clean shearing action. Adjustment is provided to maintain this relationship and to compensate for wear and sharpening. 2. The moveable blade is prevented from distorting by the combination of the blade brace and the triangular web between them that together form a rigid blade assembly. 3. The use of a vertical moveable blade and a horizontal, protruding fixed blade minimizes tarry buildup since the fixed blade acts as a scraper to keep the moveable blade substantially clean. Since this buildup occurs mainly on wide surfaces, the edge of the fixed blade also remains substantially clean. 4. The use of a fixed blade that protrudes beyond the side of the work surface provides clearance for the shingle cutoff, or waste piece, to curl downward during the cut and fall away without dragging on the side of the work surface, which would force the shingle out of position during the cutting stroke. 5. The use of a moveable guide fence permits accurate and repeatable angled or ninety degree cuts. A detent arrangement provides a positive stop for ninety degree cuts. 6. With the guide fence supporting the edge of the shingle furthest from the pivot shaft, the shingle is prevented from sliding in response to the action of the blade. In my apparatus the action of the blade tends to hold the shingle more securely against the guide fence. 7. The guide fence is easily repositioned on the work surface to permit length-wise cutting of shingles. A detent arrangement positively locates the guide fence parallel to the blades and automatically produces proper width cut pieces in accordance with the several standard dimensions used by shingle manufacturers. 8. The design of the pivot shaft minimizes the accumulation of shingle debris land granules that would inhibit proper operation of the moveable blade. The open end of the blade tube extends under the protruding fixed blade to deflect falling debris. More importantly, there is no precision ball or roller bearing mechanism that would be vulnerable to infiltration of debris as well as inflitration of moisture which would create rust. By eliminating a precision bearing, a potential maintainance problem due to rust or contamination is avoided and the apparatus will be simplified. 9. The design of the rear leg enables the user to anchor the device with his or her foot while operating the apparatus if desired. At the same time, the user's foot is protected from injury since it is shielded by the raised frame. 10. The overall shape of the frame assembly is conducive to use on a scaffolding as well as on the roof surface. A leg arrangement providing three points of support results in stability of the apparatus while in use. 11. The handle of the moveable blade does not extend significantly rearward of the footprint outlined by the three points of support of the base assembly. This avoids destabilizing of the apparatus when making a cut. The fact that the blades are laterally within this footprint keeps the apparatus from tipping to the right during operation. Further objects and advantages of my invention will become apparent from a consideration of the drawings and subsequent description. DESCRIPTION OF THE DRAWINGS In the drawings, closely related figures have the same number but different alphabetic suffixes. FIG. 1 shows a shingle cutting apparatus with the moveable blade assembly in an open position and the guide fence assembly located for angled cutting. FIG. 2 shows the apparatus with the blade assembly in a closed position and the guide fence assembly located for lengthwise cutting. FIG. 3 shows the frame assembly. FIGS. 3A and 3B are cross sections of the frame assembly. FIG. 4 shows the guide fence assembly. FIG. 4A is a cross section of the guide fence assembly. FIG. 5 shows the moveable blade shaft assembly. FIG. 5A is a cross section of the moveable blade assembly and moveable blade shaft FIG. 6 is a partial view of the moveable blade assembly showing the blade tube extension. FIG. 7 shows an alternate method of adjusting the blade shaft assembly. FIGS. 8A, 8 B, and 8 C are schematics showing the positions of shingles while being cut. FIG. 9 shows a partial cross section of the moveable blade assembly, the blade shaft assembly, and washer in an alternate embodiment using a spring. FIG. 10 shows a partial view of the crossbar, the shaft mounting bracket, the washer, and moveable blade assembly in the alternate embodiment with the spring. REFERENCE NUMERALS IN DRAWINGS 10. Frame assembly 11. Fixed blade support rail 12. Fixed blade 13. Screw 14. Semicircular rail 15. Guide fence locating plate 16. Crossbar 17. Crossbar brace 18. Front leg 19. Rear leg 20. Rear leg extension 21. Resilient foot 22. Blade stop 23. Guide fence anchor pin hole 24A. Guide fence anchor pin hole 24B. Guide fence anchor pin hole 25. Detent hole 26A. Detent hole 26B. Detent hole 27. Shaft bracket bolt hole 28. Blade shaft hole 30. Guide fence assembly 31. Guide fence 32. Anchor pin 33. Clamp bolt 34. Washer 43. Moveable blade shaft 44. Shaft washer 45. Shaft lock nut 46. Shaft mounting bracket 47. Mounting bracket hole 48. Mounting bracket bolt 49. Flat washer 50. Shim 51. Nut 54. Moveable blade assembly 55. Blade 56. Cutting edge 57. Cutting edge mounting screw 58. Blade brace 59. Blade tube 60. Blade web 61. Handle support 62. Handle 63. Blade tube extension 69. Adjustment set screw 70. Spring 71. Shingle waste piece 72. Shingle piece desired 73. Line of cut achieved DESCRIPTION OF THE PREFERRED EMBODIMENT A shingle cutting apparatus as shown in FIGS. 1-10 consists of a frame assembly 10 , including reference numerals 11 through 28 ; a guide fence assembly 30 , including reference numerals 31 through 39 ; a moveable blade shaft assembly 42 including reference numerals 43 through 51 ; and a moveable blade assembly 54 including reference numerals 55 through 63 . The several components are made of metal or other suitable material. FRAME ASSEMBLY 10 : As shown in FIG. 3, frame assembly 10 has a fixed blade support rail 11 , a semicircular rail 14 , a guide fence locating plate 15 , a crossbar 16 , and a crossbar brace 17 that together provide a working surface for the shingle being cut. As shown by FIGS. 1 and 3, support rail 11 carries a fixed blade 12 secured by screws 13 . Fixed blade 12 may be made of mild steel, carbide steel, or other suitable material. FIG. 3A shows rail 11 to be of inverted L shape with blade 12 extending laterally to the right, overhanging rail 11 . FIG. 3B shows rail 14 also to be in the form of an inverted L having a surface to support guide fence assembly 30 and a lower rim to permit gripping by a clamp bolt 33 , seen in FIG. 4 . Again referencing FIG. 3, two front legs 18 and a rear leg 19 with a rear leg extension 20 support the apparatus at a convenient height above the surface on which it is used. Resilient feet 21 are provided to afford non-skid positioning of the apparatus and to protect the surface on which it is placed. A blade stop 22 is incorporated into frame assembly 10 to provide a positive limit to the downward cutting stroke. Guide fence anchor pin holes 23 , 24 A, and 24 B are provided in plate 15 for the proper positioning of guide fence assembly 30 , shown in FIGS. 1, 2 , and 4 , in the locations needed for operation. Referring to FIGS. 3 and 4, hole 23 receives an anchor pin 32 on fence assembly 30 when an angled or a ninety degree cut is desired. Sufficient clearance is provided beneath plate 15 in the vicinity of hole 23 to permit unrestricted movement of the angled portion of pin 32 as it describes an arc in response to the repositioning of fence assembly 30 along rail 14 . Holes 24 A and 24 B receive pin 32 when fence assembly 30 is oriented for lengthwise cuts. A detent hole 25 engages a detent ball 39 on fence assembly 30 for alignment at a right angle to blade 12 . Detent holes 26 A and 26 B engage detent ball 39 when fence assembly 30 is oriented for lengthwise cutting. A shaft bracket bolt hole 27 is an elongated hole which receives a bolt 48 to attach a shaft mounting bracket 46 , shown in FIG. 5. A blade shaft hole 28 accepts the threaded end of a moveable blade shaft 43 , also shown in FIG. 5 . GUIDE FENCE ASSEMBLY 30 : Guide fence assembly 30 , as shown in FIGS. 4 and 4A, has a guide fence 31 with L-shaped anchor pin 32 attached at one end. A clamp bolt 33 , a washer 34 , and a clamp knob 35 are installed in a clamp bolt housing 36 and designed such that tightening knob 35 causes bolt 33 to grip frame rail 14 , and at the same time force the angled portion of anchor pin 32 to contact the underside of plate 15 as shown in FIGS. 1 and 2. FIG. 4A shows a cross section of guide fence assembly 30 taken at the location of detent ball 39 and a detent spring 38 captive in a detent bore 37 . Detent ball 39 engages holes 25 , 26 A, or 26 B on frame rail 14 depending on the positioning of guide fence assembly 30 . MOVEABLE BLADE SHAFT ASSEMBLY 42 : FIG. 5 shows moveable blade shaft assembly 42 , which attaches to frame assembly 10 by means of holes 27 and 28 . After passing through a washer 44 and a blade tube 59 of moveable blade assembly 54 , a moveable blade shaft 43 is inserted through hole 28 and secured with another washer 44 and a shaft lock nut 45 . FIG. 5A shows a cross section of the assembled positions of these parts. Shaft asembly 42 is further secured through a hole 47 in a shaft mounting bracket 46 by a bolt 48 , two washers 49 , and a nut 51 . One or more shims 50 are provided to adjust the position of blade assembly 54 . MOVEABLE BLADE ASSEMBLY 54 : Moveable blade assembly 54 is shown in FIGS. 1, 2 , and 6 and in cross section in FIG. 5 A. An elongate support arm 55 , supporting a blade 56 , is attached to a blade brace 58 and a blade tube 59 and is maintained substantially straight and rigid by a blade web 60 . Blade tube 59 is cylindrical in shape and large enough in inside diameter to preclude contact with shaft 43 . A blade tube extension 63 , seen in FIGS. 5A and 6 reaches under rail 11 and blade 12 . The only points of contact between shaft 43 and blade assembly 54 are where the shaft passes through holes in arm 55 and brace 58 . A handle support 61 connects a handle 62 to blade assembly 54 . Blade 56 is detachably secured to arm 55 with mounting screws 57 . Blade 56 may be either curved as shown or straight and may be made of mild steel, carbide steel, or other suitable material. ASSEMBLY OF THE COMPONENTS: When installed according to the previous description, blade assembly 54 is maintained in firm contact with fixed blade 12 by tightening lock nut 45 while mounting bracket 46 is loosely attached to crossbar 16 . Since hole 27 is elongated, blade assembly 54 is free to move laterally in response to the tightening of lock nut 45 . One or more shims are then inserted between mounting bracket 46 and crossbar 16 , as shown in FIG. 5, to bring the handle end of blade assembly 54 into tight contact with the corresponding end of fixed blade 12 . By varying the setting of lock nut 45 and the number of shims 50 used, blade 56 can be made to slide across fixed blade 12 with sufficient tension to remain in contact during use but not so tight as to inhibit the movement of blade assembly 54 . Once the proper number of shims has been inserted, bolt 48 and nut 51 are tightened, thereby maintaining the adjustment. This sequence will be repeated when final blade 12 and moveable blade 56 are replaced or sharpened. Referring to FIGS. 1 and 4, guide fence assembly 30 is installed by tilting it to enable anchor pin 32 to be inserted in hole 23 and then engaging clamp bolt 33 at the desired location on rail 14 . Tightening clamp knob 35 secures fence assembly 30 in place. By loosening clamp knob 35 , the fence assembly may be pivoted to any desired location on rail 14 without removal. Detent ball 39 engages detent hole 25 to orient fence assembly 30 for right angle cuts. Use of holes 24 A and 26 A, or alternatively, holes 24 B and 26 B, allows positioning of fence assembly a 30 for lengthwise cuts as needed. Clamp bolt 33 secures fence assembly 30 in these locations as well, as shown in FIG. 2 . ALTERNATIVE EMBODIMENTS As shown in FIG. 7, an alternate means of adjusting moveable shaft assembly 42 is with the use of threaded set screws 69 in lieu of shims 50 . In this embodiment, the assembly and adjustment sequence is analagous to the preferred embodiment except for this substitution. The adjusting of the set screws 69 takes the place of the function of the shims. FIGS. 9 and 10 show another embodiment, utilizing a spring 70 disposed on shaft 43 that takes the place of shims 50 or set screws 69 . In the assembly of this embodiment, lock nut 45 is tightened as previously detailed and spring 70 automatically provides the adjustment function that is manually achieved in the other embodiments described. OPERATION The present invention can be used on the ground, on scaffolding, or on the roof itself. FIGS. 8A-C indicate the juxtapositioning of shingles on the apparatus. Those reference numerals that are not indicated in FIGS. 8A-C are shown in FIGS. 1 through 4. FIG. 8A shows guide fence assembly 30 configured for making an angled crosscut on a shingle. For this type of cut, anchor pin 32 is located in hole 23 on plate 15 . With clamp knob 35 loose, fence assembly 30 is pivoted to the desired angle. Knob 35 is then tightened, engaging the lower edge of rail 14 and at the same time causing anchor pin 32 to contact the underside of plate 15 , effectively locking fence assembly in position. The user then grasps the handle 62 and raises blade assembly 54 . The shingle is inserted against fence assembly 30 and positioned over fixed blade 12 at the appropriate point to produce the desired size cut piece. The user brings blade asembly 54 downward, shearing the shingle, creating a desired cut piece 72 and a waste piece 71 . FIGS. 8A-C indicate the outline of the visible portions of the shingles with a dot-dot-dash line and that portion of waste piece 71 that is beneath blade assembly 54 by a dotted line. If a right-angled cut is needed, clamp knob 35 is loosened and fence assembly 30 is rotated along rail 14 until detent ball 39 engages hole 25 . Knob 35 is then tightened and cutting proceeds as above. FIGS. 8B and 8C show the two-step cutting process to produce a lengthwise cut. First, fence assembly 30 is detached by loosening knob 35 until clamp bolt 33 can be completely disengaged from rail 14 . Fence assembly 30 is tilted forward to allow anchor pin 32 to be removed from hole 23 . Anchor pin 32 is then inserted in hole 24 A or 24 B in plate 15 , depending upon the width of cut piece 72 that is desired. Detent ball is then engaged in hole 26 A or 26 B respectively and clamp bolt 33 is secured under rail 14 by tightening knob 35 . Holes 24 A and 26 A are used in concert, as are holes 24 B and 26 B. Due to the length of the shingle, the cut will be made in two passes. Blade assembly 54 is raised, the shingle is inserted along fence assembly 30 as far into the blade as it will go, as represented in FIG. 8B, and the cutting stroke is made. The shingle will be cut somewhat more than halfway along, and the waste piece 71 will fall away to the extent that it has been cut. Blade assembly 54 is then raised. The shingle is then advanced into the blade. Shingle piece desired 72 will slide forward over the front end of frame assembly 10 and waste piece 71 will slide forward under crossbar 16 . This position is represented in FIG. 8C. A second stroke of the blade is now made, completing the cut. If desired, the user may brace the apparatus with his or her foot placed on leg extension 20 for additional stability. The method of adjusting blade tension is described in detail in the section ASSEMBLY OF THE COMPONENTS under the heading DESCRIPTION OF THE PREFERRED EMBODIMENT. CONCLUSIONS, RAMIFICATIONS, AND SCOPE By utilizing rigidly designed frame and moveable blade assemblies, cutting action is efficient and not hampered by distortion of the apparatus. The adjustability incorporated into the blade assembly mounting system, previously detailed, allows the crisp cutting action to be maintained in the face of variables such as sharpening and wearing of the blades. The overall size and shape of the apparatus make it convenient to use. The apparatus is designed to tolerate a hostile working environment. It will not be negatively affected by limited exposure to wet weather on a construction site. The open design of the working surface as well as the protective extension of the blade tube tend to prevent shingle granules and debris from accumulating and hindering operation. The avoidance of any type of precision bearing in favor of a simpler design is further recognition of the adverse effects of moisture and debris infiltration. The versatility of the guide fence design permits cuts of any orientation to be made quickly and easily. The overall configuration of the apparatus renders it stable in use, and thus safe for the operator. The overhanging fixed blade provides clearance for the shingle waste piece to fall away cleanly, and not drag on the side of the frame to force the shingle out of position during the cut. While my foregoing description contains many specifics, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof. Other variations are possible, for example: 1. Referencing FIGS. 9 and 10, means to maintain tension between moveable blade assembly 54 and fixed blade 12 may comprise a spring 70 on blade shaft 43 in lieu of shims 50 or set screws 69 . 2. Fixed blade 12 and cutting edge 56 can be made integral with their respective assemblies, rather than detachable as shown in FIGS. 1 and 3. 3. Blade web 60 may be made of perforated or expanded mesh material to save weight, rather than the solid material shown in FIG. 2 . 4. Rear leg extension 20 may be eliminated for simplicity. 5. Threaded set screws 69 may be substituted for shims 50 shown in FIG. 5 . This alternate embodiment is shown in FIG. 7 . 6. Frame rail 14 may be inscribed with radial markings and numerals indicating angular degrees for reference in positioning guide fence assembly 30 . Fence assembly 30 may likewise be inscribed with length markings and numerals to assist in positioning the shingle being cut. 7. Blade tube extension may be eliminated for simplicity. 8. Detent ball 39 , spring 38 , and bore 37 may be eliminated for simplicity. If this is done, holes 25 , 26 A and 26 B would likewise be eliminated. 9. The semicircular area between rail 14 and rail 11 may be filled in with perforated, mesh, or solid material. Accordingly, the scope of the invention should be determined not by the embodiment illustrated, but by the appended claims and their legal equivalents.

4y

This is a divisional of application Ser. No. 08/528,215 filed Sep. 13, 1995, now U.S. Pat. No. 5,795,458. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a manufacturing method for a thin film diode (TFD) in a liquid crystal display (LCD) device. In the liquid crystal display device (LCD) having a structure where a liquid crystal is sealed between two glass substrates, to display a specified image by driving the liquid crystal, a thin film diode (TFD) serving as an active element (switching element) is arranged between a data line formed on an under glass substrate and each of the drive electrodes arranged in a dot matrix fashion. With such structure, interference between pixels can be prevented, thereby enhancing a quality of the displayed image. The present invention relates to a manufacturing method for such a thin film diode. 2. Description of the Prior Art The structure of a liquid crystal display device to which the present invention is applied will be described with reference to FIGS. 1 to 3. First, with reference to FIG. 1, the total constitution of the color liquid crystal display will be described. In FIG. 1, reference numeral 1 denotes an under glass substrate, and reference numeral 11 denotes an upper glass substrate. A stripe-shaped data line 12 and a plurality of drive electrodes 13 arranged in a dot matrix fashion are formed on the lower glass substrate 1. A thin film diode (TFD) 8 serving as an active element (switching element) is disposed between the data line 12 and each of the drive electrodes 13. An orienting film 15 made of a polyimide resin film to orient liquid crystals is disposed on the data line 12, the drive electrodes 13, and the thin film diode 8. On the other hand, a color filter 17 composed of color filter elements is disposed under the surface of the upper glass substrate 11. A black matrix 16 is formed in the boundary regions of the color filter elements. The red (R), green (G), and blue (B) color filter elements are arranged so as to correspond to each of the drive electrodes 13 on the glass substrate 1, respectively. A stripe-shaped scanning electrode (not shown) is disposed under the surface of the color filter 17 interposing an insulating film (not shown). The scanning electrode is in a perpendicular to the data line 12. Further, an orienting film 18 made of a polyimide film serving for orienting the liquid crystal is disposed on the scanning electrode. A liquid crystal (not shown) is sealed between the orientating films 15 and 18. Further, polarizing plate 19 and 20 are arranged on each outer surface of the lower and upper glass substrate 1 and 11 respectively so that the polarized axises thereof are perpendicular to each other. In the liquid crystal display device described above, if the color filter 17 is omitted, the liquid crystal display dedive functions as a black/white liquid crystal display device. Next, referring to FIG. 2 and FIG. 3, a structure of the thin film diode 8 incorporated in the liquid crystal display device of the present invention will be described. FIG. 3 is a sectional view taken along the line III--III shown in a plan view of FIG. 2. The thin film diode 8 has a Metal-Insulator-Metal structure composed of a lower layer film 2 protruding from the data line 12, an insulating film 3 formed on the surface of the film 2, and an upper layer film 4 formed on the film 3. The upper layer film (electrode) (hereinafter referred to as upper layer film) 4 serves as a part of the drive electrode 13. Specifically, a punched portion 13a is formed in the drive electrode 13 close to the portion thereof which crosses the lower layer film (electrode)(hereinafter referred to as lower layer film) 2, so that the thin film diode 8 presents a plan view pattern in which the lower and upper layer films 2 and 4 cross. A manufacturing method of the thin film diode 8 will be briefly described below. A tantalum (Ta) film as a material for the data line 12 and the lower layer film 2 is formed on the glass substrate 1. The tantalum (Ta) film is patterned by means of a photo-etching processing. Thereafter, an anodic oxidation processing is carried out using the patterned tantalum (Ta) film as an anode to form the insulating film 3 made of a tantalum pentoside (Ta 2 O 5 ) on the tantalum (Ta) film. This anodic oxidation processing is performed in such a manner that citric acid, the tantalum film, and platinum (Pt) are used as an anodic oxidation liquid, an anode, and a cathode, respectively, and a direct current is applied between the tantalum film and platinum. Thereafter, indium-tin-oxide (ITO) film serving as a material for the drive electrode 13 and the upper layer film 4 is formed on the entire surface. Then, the indium oxide tin film is subjected to patterning by means of a photo-etching processing so that the upper layer film 4 and the drive electrode 13 are formed. The conventional constitution and manufacturing method thereof of a thin film diode 8 in such a liquid crystal display device will be further described with reference to FIGS. 4 to 7. The vertical sectional view of the lower layer film 2 constituting the thin film diode on the glass substrate 1 presents either a rectangular shape as shown in FIG. 4 or a tapered-trapezoidal shape as shown in FIG. 5. The reason why it presents such the shape is that patterning of the film 2 is ordinarily carried out by one etching process. Specifically, in a manufacturing method for such a thin film diode, the substance for the lower layer film is initially formed on the upper surface of the glass substrate 1 by either a sputtering technique or a chemical vapor deposition technique. Subsequently, a resist pattern is formed on the substance for the lower layer film by using a lithography technique. Thereafter, an etching processing by means of either a wet etching technique or a dry etching technique is carried out using the patterned resist as a mask to form a pattern of the lower layer film 2 as shown in FIG. 4 or FIG. 5. When etching the lower layer film, it is difficult to control the etching shape by the wet etching technique. However, with the dry etching technique, it is possible to produce the tapered-trapezoidal shape shown in FIG. 5 by controlling an etching speed ratio of the resist to the substance for the lower layer film. Subsequently, as shown in FIG. 6 or FIG. 7, an anodic oxidation process using the lower layer film 2 as an anode is performed to form the insulating film 3 on the surface of the film 2. Further, a substance for the upper layer film is formed on the insulating film 3 by either the sputtering technique or the chemical vapor deposition technique. Thereafter, a resist pattern (not shown) is formed on the substance for the upper layer film by the lithography technique. Following the above processes, an etching process to form the pattern of the upper layer film 4 is carried out by either the wet etching technique or the dry etching technique using the patterned resist as a mask. As a result, the thin film diode 8 of the Metal-Insulator-Metal structure is completed. At the time of the formation of the thin film diode, it is essential to form a region where the lower and upper layer films 2 and 4 overlap each other. The upper layer film 4 overlapping with the lower layer film 2 sometimes breaks at its step portion. The situation of the breaking of the film 4 will be described with reference to FIGS. 6 and 7. Referring to FIG. 6, the region where the upper layer film 4 is formed stretches over the glass substrate 1 and the insulating film 3. Therefore, the film property of the film 4 on the insulating film 3 is different from that on the glass substrate 1 due to the difference of the materials of the substrate 1 and the film 3. Specifically, the boundary due to the difference of the film natures is produced between the glass substrate 1 and the insulating film 3. Further, a growth direction of the covering film serving as the upper layer film 4 on the etched side region of the glass substrate 1 is different from that thereof on the etched side region of the lower layer film 2. As a result, both growth directions meet with each other at the boundary so that a crystallinity of the film 4 is deteriorated at the boundary. Therefore, the crystallinity of the covering film serving as the upper layer film 4 is deteriorated in addition to the difference of the film property at the boundary region (shown by the arrow A) between the glass substrate 1 and the insulating film 4. Thus, the portion of the covering film at the boundary region is more liable to break than other portions thereof. The occurrence of such breaking of the film produces a defective pixel, leading to a decrease in a quality of the liquid crystal display device. Especially, when the surface of the lower layer film 2 is oxidized by the anodic oxidizing technique to form the insulating film 3 and the patterned upper layer film 4 formed on the film 3, the film 3 is formed only on the surface of the lower layer film 2. Thus, the upper layer film 4 is formed stretching over the glass substrate 1 and the insulating film 3 which have different natures. This causes severe problems. Moreover, the insulating film 3 grows isotopically during the formation thereof using the anodic oxidation technique. Accordingly, though the section of the lower layer film 2 formed on the glass substrate 1 is made into a taper-shaped trapezoid by etching as shown in FIG. 5, the section of the insulating film 3 presents the shape shown in FIG. 7. The portion of the insulating film 3 at the boundary between the glass substrate 1 and the film 3 does not present the tapered shape so that the effects of the tapered shape is decreased. For this reason, the portion of the upper layer film 4 at the boundary (shown with an arrow B) between the glass substrate 1 and the insulating film 3 is also apt to be broken. SUMMARY OF THE INVENTION The object of the present invention is to reduce the breaking of an upper layer film constituting a thin film diode in order to increase the quality of display of a liquid crystal display device serving as an active element incorporated in the liquid crystal display device. To achieve the above object of the present invention, the present invention provides the following manufacturing method for the thin film diode of the liquid crystal display device. Specifically, a film of a lower layer film material is formed on a glass substrate, and a resist pattern is formed on the upper layer film material by a photo-lithography technique. The lower layer film material is subjected to an etching process using the pattern of the resist as an etching mask to form a pattern of the lower layer film, thereafter, the dimension of the resist pattern is lessened. The exposed portion of the lower layer film is etched using the lessened pattern of the resist as an etching mask until the thickness of the film is reduced to a predetermined value. Thus, the lower layer film has a difference in level which overlaps with an upper layer film in a thickness direction. Thereafter, an insulating film is formed on the surface of the lower layer film by an anodic oxidation process, and then the upper layer film is formed on the insulating film. Further, after the pattern of the lower layer film is formed in a similar manner to the above process, the resist is peeled off. An insulating film material is formed on the pattern of the lower layer film. This insulating film material is subjected to an anodic oxidation process to form an insulating film. Or, the insulating film material may be oxidized together with a lower layer film. Thereafter, the upper layer film may be formed on the lower layer film. The insulating film material may be either the same material as that of the lower layer film material or a different material from that of the lower layer film, as long as it is a material that the insulating film can be formed from by the anodic oxidation process. For example, tantalum (Ta) or aluminum (Al) may be used. The following manufacturing method may be adopted as another manufacturing method. Specifically, the pattern of a resist having a different pattern dimension from that of the resist used for the etching of the lower layer film is formed on the insulating film material formed in the form of a film. The insulating film material is patterned by etching the material using this resist as an etching mask. The patterned insulating film material or the exposed portion of the lower layer film from the insulating film material is oxidized by the anodic oxidation process, thereby forming the insulating film having the difference in level around the lower layer film. The following manufacturing method may be employed as another manufacturing method. Specifically, after the insulating film and the anodic unoxidized portion are formed by oxidizing the insulating film material formed in the form of the film with the anodic oxidation technique, the pattern of the upper layer film is formed on the insulating film located on the lower layer film. The etching process for the insulating film and the anodic unoxidized portion can be performed by using the pattern of the upper layer film as an etching mask. Alternatively, the pattern of the resist having the larger pattern dimension than that of the upper layer film is formed thereon, and the etching processing for the insulating layer film and the anodic unoxidized portion may be performed using the pattern of the resist. Further, a protection film is additionally formed on the pattern of the upper layer film, and the etching processing for the insulating film and the anodic unoxidized portion can be performed using the pattern of the protection film. Further, there is also the following manufacturing method for the thin film diode of the present invention. A lower layer film material is formed on a glass substrate in the form of a film. The pattern of a resist is formed on the lower layer film by a photo-lithography technique. The lower layer film is etched using the pattern of the resist as an etching mask until the thickness of the lower layer film is reduced to a predetermined value in a thickness direction. Thereafter, the pattern dimension of the resist is changed. The lower layer film material is further etched using the pattern of the resist, thereby forming the lower layer having a difference in level in the direction of overlapping of the upper layer film with the lower layer film. An insulating film is formed on the surface of the lower layer film by anodic oxidation processing, and the lower layer film is formed on the insulating film. After etching the lower layer film material formed in the form of the film in the direction of the film thickness, the resist used for the etching mask is peeled off, the lower layer film material is oxidized by the anodic oxidation technique to form the insulation film. The lower layer film is patterned. Further, there is another manufacturing method for the thin film diode of the present invention following. A lower layer film material is formed on a glass substrate. The pattern of a resist is formed on the lower layer film material by a photo-lithography technique. The lower layer film material is etched using the pattern of the resist as an etching mask to form the pattern of the lower layer film. Thereafter, a film of an insulating film material is formed on the glass substrate and the resist. The film of the insulating film material formed on the resist is removed, as well as the resist. The surfaces of the insulating film material formed on the glass substrate and the lower layer film are oxidized by an anodic oxidation technique to form an insulating film. An upper layer film is formed on the insulating film. When the thin film diode incorporated in the liquid crystal display device is manufactured using these manufacturing methods, the overlapping area of the upper layer film with the lower layer film is larger than that of the thin film diode of the conventional embodiment, and the differences of the film qualities between the insulating film of an element region of the thin film diode and that of the vicinity thereof are not caused. For this reason, elements with defects due to breaks at the differences in level are greatly reduced so that the display quality of the liquid crystal display device can be remarkably enhanced. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view showing partially a liquid crystal display device to which the present invention is applied; FIG. 2 is a plan view showing a constitution of a thin film diode of the present invention; FIG. 3 is a sectional view taken along the line III--III in FIG. 2; FIGS. 4 and 5 are sectional views showing a vertical section of a lower layer film formed on a glass substrate at the time of manufacturing of a conventional thin film diode; FIGS. 6 and 7 are vertical sectional views showing a constitution of the conventional thin film diode manufactured using the lower layer film of FIGS. 4 and 5, respectively; FIG. 8 is a sectional view showing an example of a lower layer film formed on a glass substrate at the time of manufacturing a thin film diode of the present invention; FIG. 9 is a vertical sectional view showing a constitution of the thin film diode manufactured using the lower layer film shown in FIG. 8 of the present invention; FIGS. 10, 12, and 14 are sectional views showing different examples of the vertical sections of the lower layer film formed at the time of manufacturing the thin film diode of the present invention; FIGS. 11, 13, and 15 are vertical sectional views showing constitutions of the thin film diodes manufactured using the lower layer films of FIGS. 10, 12, and 14; and FIGS. 16 to 64 are sectional views of the glass substrate and the thin film diode forming portion showing the different steps for explaining various kinds of manufacturing methods of the thin film diode of the present invention DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A variety of embodiments of a thin film diode incorporated in a liquid crystal device according to the present invention will be sequentially described with reference to the accompanying drawings. Firstly, the structure of the thin film diode manufactured by manufacturing methods of the present invention will be described with reference to FIGS. 8 and 9. As shown in FIG. 8, a lower layer film 2 formed on a glass substrate 1 comprises a higher step portion 2a and a lower step portion 2b, and its vertical section presents a level difference at least in a direction of an upper layer film's overlapping with the lower layer film. An insulating film 3 is formed by oxidizing the surface of the lower layer film 2 using an anodic oxidation technique. An upper layer film 4 is formed on the insulating film 3. Thus, an element of a thin film diode (TFD) 8 having the structure shown in FIG. 9 is obtained. In this embodiment, the lower step 2b of the lower layer film 2 having a thickness d is entirely converted to the insulating film 3 when the surface of the lower layer film 2 is oxidized by the anodic oxidizing technique. The portion of the insulating film 3 in the vicinity of the boundary between the glass substrate 1 and the lower layer film 2 is thicker than the conventional lower layer film by the thickness d of the lower step portion 2b. Although this causes a decrease in the height and width of the higher step 2a, the unoxidized portion remains as the lower layer film 2. Therefore, the insulating film 3 is formed stretching over the surface of the residual lower layer film 2 and the glass substrate 1, exhibiting the step shown in FIG. 9. As described above, since the insulating film 3 has the step, the upper layer film 4 formed stretching over the glass substrate 1 and the lower layer film 2 has two step portions. Therefore, the difference in level for each step is decreased to half. A load for each step portion is decreased, thereby being able to decrease breaks at the step portion. In the above embodiment, the vertical section of the lower layer film 2 before the formation of the insulating film 3 by the anodic oxidation of the lower layer film 2 presents two step portions. As a matter of course, the number of the step portions may be three or more. Referring to FIG. 10, when forming the thin film diode 8 using the lower layer film 2 having three step portions, the structure shown in FIG. 11 is obtained. In this case, the surface of the insulating film 3 is oxidized by the thickness equal to that of the two step portions shown in FIG. 10, by oxidizing the surface of the lower layer film 2 using the anodic oxidation technique. Further, the vertical section of the lower layer film 2 before the formation of the insulating film 3 may be a tapered trapezoid having two tapered step portions as shown in FIG. 12. The formation of the thin film diode 8 using the lower layer film 2 of the vertical section shown in FIG. 12 produces the structure as shown in FIG. 13. Moreover, the vertical section of the lower layer film 2 before the formation of the insulating film 3 may be a trapezoid having such lower and upper tapered step portions that the taper angle of the lower tapered step portion near the glass substrate 1 is very small and the taper angle of the upper tapered step portion is larger than that of the lower tapered step portion as shown in FIG. 14. The formation of the thin film diode 8 using the lower layer film 2 of the vertical section shown in FIG. 14 produces the structure as shown in FIG. 15. By using the lower layer film 2 shown in FIG. 14, the accuracy of patterning the films 3 and 4 is not decreased and the taper angle of the upper layer film 4 will be substantially equal to that of the lower layer film 2. Next, the manufacturing method of the thin film diode of the present invention will be described for forming the thin film diode on the glass substrate of the liquid crystal display device. The embodiment in which tantalum (Ta) for the lower layer film 2 and indium-tin-oxide (ITO) for the upper layer film 4 are used will be described. A First Manufacturing Method! A first manufacturing method of the thin film diode of the present invention will be described. First, as shown in FIG. 16, a tantalum film 20 of 50 nm to 500 nm thickness for the lower layer film material is formed on the glass substrate 1 by a sputtering technique. Subsequently, the patterned resist 6 of the same pattern as the tantalum film 20 is formed on the tantalum film 20 by the photo-lithography technique. The formation of the tantalum film 20 is performed under the following conditions. Specifically, argon gas of flow rate 100 sccm is conducted into a sputtering device, and the pressure at the device is regulated at the pressure 5 mTorr. Radio frequency (RF) electrical power (oscillation frequency: 13.56 MHz) of 1 KW to 3 KW is applied to generate plasma. Tantalum as a target material is sputtered by the plasma. The sputtered tantalum is deposited on the glass substrate 1. Using the patterned resist 6 as a mask, the tantalum film 20 is subjected to either the dry etching process or the wet etching process to form a pattern of the lower layer film 2 as shown in FIG. 17. When the tantalum film 20 is etched by the dry etching process, sulfur hexafluoride (SF6) of flow rate 100 to 500 sccm is conducted into a dry etching device, and oxygen of flow rate 0 to 100 sccm is added to the sulfur hexafluoride (SF6). Thus, a total pressure of 50 to 200 mTorr at the dry etching device is produced. Radio frequency electrical power (oscillation frequency: 13.56 MHz) of 100 to 1000 W is applied thereto. Plasma is generated. The dry etching is performed with this plasma. When the tantalum film 20 is etched by the wet etching process, the process is carried out by using a solution prepared by mixing sulfur hexafluoride, nitric acid, ammonium fluoride, and water in a ratio of 5:2:1:3. Thereafter, ashing process for the resist 6 on the lower layer film 2 is performed to reduce the pattern dimension of the resist 6 as shown in FIG. 18. This ashing process is performed by plasma produced in the following way. Oxygen of a flow rate 100 to 1000 sccm is conducted into the dry etching device, and sulfur hexafluoride of a flow rate 0 to 100 sccm is added. The total pressure at the device is regulated at 100 to 300 mTorr. Radio frequency electrical power (oscillation frequency: 13.56 MHz) of 100 to 500 W is applied thereto. Thus, plasma is generated under the above conditions. At the time of the ashing, etching of the lower layer film 2 which is the tantalum film slightly proceeds by regulating the quantity of sulfur hexafluoride, and the exposed portion a that is not covered with the resist 6 by the ashing process may be made a tapered-shape. Next, as shown in FIG. 18, using the resist 6 of the reduced pattern dimension as a mask, either the dry etching process or the wet etching process for the lower layer film 2 is carried out. The etching process proceeds in the direction of the film thickness and is stopped at midway, thereby forming the step portion in the lower layer film 2 as shown in FIG. 19. The resist 6 on the lower layer film 2 is peeled off, thereby obtaining the lower layer film 2, the vertical section of which has a step portion as shown in FIG. 8. Thereafter, the surface of the lower layer film 2 is oxidized by anodic oxidation so that the insulation film 3 is formed. The patterned upper layer film 4 is formed thereon. As a result, the thin film diode 8 of the structure shown in FIG. 9, where the breaking of the upper layer film 4 is not caused, can be manufactured on the glass substrate 1. This anodic oxidation process is performed as follows. Using citric acid solution of concentration 0.01 to 1%, a voltage of 10 to 100 V is applied between tantalum (Ta), as a material for the lower layer film 2, and a platinum electrode as a cathode. Further, by performing the ashing process and the etching process once again, the lower layer film 2 of the vertical section having the step portions can be formed as shown in FIG. 10. Still further, at the time of the etching process and the ashing process, by controlling the etching rate ratio of the resist 6 to the tantalum film 20 as a material for the lower layer film 2, the lower layer film 2 having the tapered-shaped vertical section can be formed as shown in FIGS. 12 and 14. Second Manufacturing Method! A manufacturing method different from the foregoing manufacturing method for the thin film diode will be described. Also in this manufacturing method, as shown in FIG. 16, the tantalum film 20 as the lower layer film is formed on the glass substrate 1 by the sputtering technique. The resist 6 is formed on the tantalum film 20 and is patterned by the photo-lithography technique. Subsequently, either the dry etching process or the wet etching process for the tantalum film 20 is performed using the resist 6 as a mask. The above steps until the formation of the patterned tantalum film 20 are the same as those of the first manufacturing method. Next, the resist 6 on the lower layer film 2 shown in FIG. 17 is peeled off. As shown in FIG. 18, a patterned resist 6 (the same reference numeral is used as that of FIG. 17 for simplicity of explanation) is again formed on the lower layer film 2 using the photo-lithography. The pattern dimension of the resist 6 of FIG. 18 is smaller than that of FIG. 17. Subsequently, either the dry etching technique or the wet etching technique for the lower layer film 2 is performed using the resist 6 having a small pattern dimension. As shown in FIG. 19, the etching process is stopped when the film 2 is etched to the predetermined thickness. As a result, the step portion of the film 2 is formed. Thereafter, the same steps as those of the first manufacturing method are performed until completion of the thin film diode shown in FIG. 9. Specifically, as shown in FIGS. 17 and 18, the second manufacturing method is different from the first manufacturing method only in that the way to reduce the pattern dimension of the resist 6 on the pattern of the lower layer film 2 is different from the ashing process in the first manufacturing method. The Third Manufacturing Method! The third manufacturing method for the thin film diode of the present invention which is different from the first and second manufacturing methods will be described. First, as shown in FIG. 16, the tantalum film 20 of 50 to 500 nm thickness as the lower layer film is formed on the glass substrate 1 by the sputtering technique. The resist 6 is formed on the film 20 and the resist 6 is patterned by the photo-lithography technique. The steps until the formation of the patterned resist 6 are the same as those of each of the foregoing manufacturing methods. Subsequently, either the dry etching process or the wet etching process for the tantalum film 20 is performed using the patterned resist 6 as a mask. The etching process is continued until the thickness of the tantalum film 20 is reduced to substantially half as shown in FIG. 20. Either the dry etching process or the wet etching process for the tantalum film 20 in the third manufacturing method is performed as in the same manner in each of the foregoing manufacturing methods. Next, as shown in FIG. 21, the ashing process for the resist 6 on the tantalum film 20 is performed, thereby reducing the pattern dimension of the resist 6. This ashing process is performed in the same manner as in the first manufacturing method. Either the dry etching process or the wet etching process for the tantalum film 20 as the lower layer film material is again performed using the resist 6 as an etching mask with the reduced pattern dimension as described above. The etching process is continued until the thin thickness portion 20b of the tantalum film 20 is reduced to the thickness t. Thereafter, the resist 6 on the tantalum film 20 is peeled off, so that the lower layer film 2 having the step portion, i.e., the two differences in level can be formed as shown in FIG. 8. Thereafter, the same steps as those of the first manufacturing method are performed until the thin film diode shown in FIG. 9 is completed. Specifically, the insulating film 3 is formed on the surface of the lower layer film 2 by the anodic oxidation technique. The patterned upper layer film 4 is formed thereon. It should be noted that the lower layer film 2 presenting the vertical section having the two step portions, i.e., three differences in level, can be formed as shown in FIG. 10 by performing the ashing and the etching processes shown in FIG. 21 once more. In addition, at the time of the ashing and etching processes, the lower layer film 2 presenting the etched vertical section having the tapered-shape as shown in FIGS. 12 or 14 can be formed by regulating the ratio of the etching speed of the resist 6 to that of the tantalum 20 as the lower layer film material. The Fourth Manufacturing Method! The fourth manufacturing method of the present invention which is partially different from the third manufacturing method will be described. In the following steps of the fourth manufacturing method, the same processes as those of the third manufacturing method are performed. Specifically, as shown in FIG. 16, the tantalum film 20 as the lower layer material is formed on the glass substrate 1. The pattern of the resist 6 having the same pattern of the lower layer film is formed thereon. Either the dry etching process or the wet etching process for the tantalum film 20 is performed using the resist 6 as a mask. The etching process proceeds until the thickness of the film 20 is reduced to the predetermined value shown in FIG. 20. After these steps, the resist 6 shown in FIG. 20 on the tantalum film 20 is peeled off. A resist having the smaller pattern dimension than that of the lower layer film is again formed thereon by the photo-lithography technique. Thus, the situation shown in FIG. 21 can be obtained. The steps from the formation of the lower layer film 2 by performing the etching process again to obtaining the thin film diode shown in FIG. 9 are the same as those of the foregoing third manufacturing method. Explanations of them are omitted. The Fifth Manufacturing Method! The fifth manufacturing method which is different from each of the foregoing manufacturing methods will be described. First, as shown in FIG. 22, the tantalum film 20 of 50 to 500 nm thickness as a lower layer material is formed on the glass substrate 1 by the sputtering technique. Thereafter, the pattern of the resist 6a having the same pattern dimension as that of the lower layer material is formed on the tantalum film 20 by the photo-lithography technique. Next, either the dry etching process or the wet etching process for the tantalum film 20 serving as a lower layer film material is performed using the patterned resist 6a as a mask. The etching process proceeds until the thickness of the tantalum film 20 is reduced to a predetermined value. Specifically, the etching process proceeds until the thickness of the thin film portion 20b becomes less than half of that of the insulating film 3. Either the dry etching process or the wet etching process for the tantalum film 20 is performed in the same manner as each of the foregoing manufacturing methods. Thereafter, as shown in FIG. 24, the resist 6a which was used as the etching mask for the tantalum film 20 is peeled off. Further, as shown in FIG. 25, the resist 6b having the larger pattern dimension than the higher step stage 20a of the tantalum film 20 is formed thereon by the photo-lithography technique. Either the dry etching process or the wet etching process for the tantalum film 20 is performed using the resist 6b having the larger pattern as a mask. The exposed portion which is the thin thickness portion of the tantalum film 20, and which is not covered with the resist 6 is removed, thereby forming the lower layer film 2 having the difference in level as shown in FIG. 26. By peeling off the resist 6b on the lower layer film 2, the lower layer film 2 which has the vertical section presenting the two differences in level, i.e., the step portion, can be obtained. After these steps, since each of the steps until the thin film diode is formed are the same as those of the first manufacturing method, explanations for them are omitted. The Sixth Manufacturing Method! The sixth manufacturing method of the thin film diode of the present invention will be described. First, as shown in FIG. 27, the tantalum film 20 of 50 to 500 nm thickness serving as the lower layer film material is used on the glass substrate 1 by the sputtering technique. Thereafter, the resist 6a having the same pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Next, either the dry etching process or the wet etching process for the tantalum film 20 is performed using the patterned resist 6a as a mask, so that the exposed portion of the tantalum film 20 which is not covered with the resist 6a is removed. Thus, the lower layer film 2 covered with the resist 6a is formed. Either the dry etching process or the wet etching process for the tantalum film 20 serving as the lower layer film material is performed in the same manner as each of the foregoing manufacturing methods. After the above processes, the resist 6a on the lower layer film 2 is peeled off, the tantalum film 7 which is the same material as that of the lower layer film 2 is formed on the entire surfaces of the glass substrate 1 and the lower layer film 2 by the sputtering technique as an insulating film, as shown in FIG. 29. Subsequently, as shown in FIG. 30, the resist 6b having the larger pattern dimension than that of the lower layer film 2 is formed on the tantalum film 7 by the photo-lithography technique. Either the dry etching process or the wet etching process for the tantalum film 7 is performed using the resist as a mask. Thus, the exposed portion of the tantalum film 7 which is not covered with the resist 6b is removed. As shown in FIG. 31, the tantalum film 7 having the two differences in level, i.e., the step portion, is left on the lower layer film 2 and the glass substrate 1 located on both sides thereof. Thus, the lower layer film 2 and tantalum film 7 made of the same material produce the same vertical section as that of the lower layer film 2 shown in FIG. 8. Thereafter, the resist 6b is peeled off, and the surface of the tantalum film 7 is oxidized by the anodic oxidation technique, thereby forming the insulating film 3 on the pattern of the lower layer film 2. The pattern of the upper layer film 4 is formed thereon so that the thin film diode 8 causing no breaking of the upper layer film 4 can be formed as shown in FIG. 9. The Seventh Manufacturing Method! The seventh manufacturing method for the thin film diode of the present invention will be described. First, as shown in FIG. 32, the tantalum film 20 of 50 to 500 nm thickness as the lower layer film material is formed on the glass substrate 1 by the sputtering technique. Thereafter, the pattern of the resist 6b having the same pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Next, either the dry etching process or the wet etching process for the tantalum film 20 is performed using the patterned resist 6b as a mask. Thus, the exposed portion of the tantalum film 20 is removed, thereby forming the lower layer film 2 as shown in FIG. 33. Either the dry etching process or the wet etching process for the tantalum film 20 is performed in the same manner as each of the foregoing manufacturing methods. Subsequently, the resist 6b on the lower layer film 2 is peeled off, and the tantalum (Ta) film 7, which serves as an insulating material, made of the same material as that of the lower layer film, is formed on the entire surfaces of the glass substrate 1 and the lower layer film 2 by the sputtering technique as shown in FIG. 34. As shown in FIG. 35, the resist 6a having the smaller pattern dimension than that of the lower layer film 2 is formed on the tantalum film 7 by the photo-lithography technique. Either the dry etching process or the wet etching process for the tantalum film 7 is performed using the patterned resist 6a with the reduced pattern dimension as a mask, thereby removing the exposed portion of the tantalum film 7 which is not covered with the resist 6a. Thus, the tantalum film 7 is left only under the resist 6a as shown in FIG. 36. Thereafter, peeling off the resist 6a, the lower layer film 2 and the tantalum film 7 in total produce the same vertical section as that of the lower layer film 2 shown in FIG. 8. The vertical section presents the two differences in level. Further, the surfaces of the tantalum film 7 and the lower layer film 2 of the same material as that of the film 7 are oxidized by the anodic oxidation technique, thereby forming the insulating film 3 on the pattern of the lower layer film 2 as shown in FIG. 9. Forming the pattern on the upper layer film 4, the thin film diode 8 in which no breaking of the upper layer film 4 occurs can be formed. In this method, tantalum (Ta) which is the same material as that of the lower layer film is used as the insulating film material. It is noted that any insulating film may be used as long as the insulating film can be obtained by performing the anodic oxidation process using it as an anode. Specifically, a different material from the lower layer film may be used. For example, while tantalum (Ta) is used as the lower layer film, aluminum (Al) which is a different material from tantalum may be used. The Eighth Manufacturing Method! The eighth manufacturing method for the thin film diode of the present invention will be described. First, as shown in FIG. 22, the tantalum film 20 of 50 to 500 nm thickness serving as the lower layer film is formed on the glass substrate 1 by the sputtering technique. After the formation of the film 20, the pattern of the resist 6a which is the same as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Either the dry etching process or the wet etching process for the tantalum film 20 is performed using the patterned resist 6a as a mask. Thus, the exposed portion of the tantalum film 20 is removed so that the portion of the tantalum film 20 under the resist 6a is left to use it as the lower layer film 2. Either the dry etching process or the wet etching process for the tantalum film 20 serving as the lower layer film is performed in the same manner as each of the foregoing manufacturing methods. Next, as shown in FIG. 38, the tantalum film 7' of the same material as that of the lower layer film is formed on the entire surfaces of the glass substrate 1 and the resist 6 by the sputtering technique as the insulating film. Subsequently, as shown in FIG. 39, the resist 6a is peeled off, at the same time, the tantalum film 7' on the resist 6a is removed. As a result, the tantalum film 7' can be formed in the region where the layer film 2, which is not covered with the resist 6a, is not formed. Thereafter, as shown in FIG. 40, the resist 6b having the larger pattern dimension than that of the lower layer film 2 is formed on the lower layer film 2 and the tantalum film 7' by the photo-lithography technique. As shown in FIG. 41, either the dry etching process or the wet etching process for the tantalum film 7' is performed using the resist 6b as an etching mask. After the etching process for the tantalum film 7', and peeling off the resist 6b, the lower layer film 2 and the tantalum film 7' left on both sides of the film 2 in total produce the same vertical section as that of the lower layer film 2 shown in FIG. 8. The vertical section presents the two differences in level, i.e. the step portion. Thereafter, the surfaces of the film 2 and the film 7' located at both sides of the film 2 are oxidized by the anodic oxidation technique, thereby forming the insulating film 3 on the pattern of the lower layer film 2 as shown in FIG. 9. The pattern of the upper layer film 4 is formed on the insulating film 3 so that the thin film diode 8 free from the breaking of the upper layer film 4 can be formed. The Ninth Manufacturing Method! The ninth manufacturing method of the thin film diode of the present invention will be described. First, as shown in FIG. 22, the tantalum film 20 of 50 to 500 nm thickness serving as the lower layer film material is formed on the glass substrate 1 by the sputtering technique. The pattern of the resist 6a having the same pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Next, as shown in FIG. 23, either the dry etching process or the wet etching process for the tantalum film 20 is performed using the resist 6a as a mask. The etching process proceeds until the tantalum film 20 is etched by the predetermined value in the thickness direction. It should be noted that the foregoing predetermined value is the thickness of the thin thickness portion of the tantalum film 20 left after the etching of the film 20 on the glass substrate 1, which must be less than half of the thickness of the anodic oxidation film to be formed later by the anodic oxidation technique. For example, when the thickness of the anodic oxidation film is required to be 200 nm, the thickness of the thin thickness portion of the tantalum film 20 left on the glass substrate 1 after the etching is set less than 100 nm. Either the dry etching process or the wet etching process for the tantalum film 20 serving as the lower layer film is performed in the same manner as each of the manufacturing methods. As shown in FIG. 24, the resist 6a on the lower layer film 2 which was used as the mask is peeled off. Subsequently, the thin thickness portion 20b of the tantalum film 20 shown in FIG. 24 is oxidized by the anodic oxidation technique using the film 20 as an anode thereby forming the insulating film 3 as shown in FIG. 42. The entire thin thickness portion 20b of the tantalum film 20 is converted to the insulating film 3. The lower layer film is patterned. Further, as shown in FIG. 43, the indium-tin-oxide (ITO) film 4a serving as the upper layer film material is formed on the insulating film 3 by the sputtering technique. The formation of the indium-tin-oxide film 4a is performed in the following manner. Specifically, argon gas of the flow rate 100 sccm and oxygen gas of the glow rate 2 sccm are conducted into the sputtering device. Total pressure in the device is regulated at 10 mTorr. Radio frequency electrical power (oscillation frequency: 13.56 MHz) of an output power 1 to 3 KW is applied to generate plasma. Indium tin serving as the target material is sputtered by the generated plasma as indium-tin-oxide. The sputtered indium-tin-oxide is deposited on the insulating film 3. Next, as shown in FIG. 43, the pattern of the resist 6c having the same pattern as that of the upper layer film is formed on the indium-tin-oxide film 4a serving as the upper layer film by the photo-lithography technique. Either the dry etching process or the wet etching process for the indium-tin-oxide film 4a is performed using the resist 6a as a mask. By this etching process for the indium-tin-oxide film 4a, the upper layer film 4 is formed as shown in FIG. 44. When the etching process for the indium-tin-oxide film 4a is performed by the dry etching technique, the etching process is performed in the following manner. Specifically, methane (CH4) of the flow rate 100 to 500 sccm is introduced into the dry etching device. Hydrogen of the flow rate 0 to 100 sccm and methanol (CH3OH) of the flow rate 0 to 100 sccm are added to the dry etching device. The total pressure at the device is regulated at 30 to 200 mTorr. Then, radio frequency electrical power of an oscillation frequency 13.56 MHz and an output power 1 to 3 KW is applied to produce plasma. The etching process is performed using this plasma. Further, when the etching process for the indium-tin-oxide film 4a is performed by the wet etching technique, it is performed using the solution in which iron hydrochloride, hydrochloric acid, and water are blended in a 3:5:2 ratio. After the etching process, the resist 6c is peeled off, thereby obtaining the thin film diode free from the breaking of the upper layer film 4. Further, at the time of the etching of the tantalum film 20 serving as the lower layer film in the manufacturing step shown in FIG. 22, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum film 20 is controlled. As a result, the vertical section of the tantalum film 20 obtained by the etching process may be tapered-shaped as shown in FIG. 46. When the thin film diode 8 is formed in the foregoing manner using the tantalum film 20 formed by this method, the vertical section, having such a structure that the upper layer film 4 is more likely to be overlapped shown in FIG. 47, is obtained. The Tenth Manufacturing Method! The tenth manufacturing method for the thin film diode of the present invention will be described. Also in this manufacturing method, first, the tantalum film 20 of 50 to 500 nm thickness serving as the lower layer film is formed on the glass substrate 1 by the sputtering technique as shown in FIG. 27. The pattern of the resist 6a having the same pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Thereafter, either the dry etching process or the wet etching process for the tantalum film 20 serving as the lower layer film is performed using the patterned resist 6a, thereby forming the pattern of the lower layer film 2 as shown in FIG. 28. Either the dry etching process or the wet etching process for the tantalum film 20 is performed in the same manner as each of the foregoing manufacturing methods. Next, the resist 6a on the lower layer film 2 is peeled off. The tantalum film 7 of the same material as that of the lower layer film 2 is formed on the entire surface including the pattern of the lower layer film 2 by the sputtering technique as shown in FIG. 29. The tantalum film 2 serves as the insulating film material. At the formation of the tantalum film 7, the thickness of the film 7 is made less than half of the thickness of the anodic oxidation film. Next, as shown in FIG. 42, the tantalum film 7 is oxidized by the anodic oxidation technique, thereby forming the insulating film 3 on the lower layer film 2. Further, as shown in FIG. 43, the indium-tin-oxide (ITO) film 4a serving as the upper lower layer film material is formed on the insulating film 3 by the sputtering technique. Subsequently, the same pattern of the resist 6c as that of the upper layer film is formed on the indium-tin-oxide film 4a by the photo-lithography technique. As shown in FIG. 44, the upper layer film 4 is formed using the pattern of the resist 6c as an etching mask by the wet etching technique. Thereafter, peeling off the resist 6c, the thin film diode 8 having the structure shown in FIG. 45 can be obtained. Further, at the time of the etching of the tantalum film 20 serving as the lower layer film in the manufacturing step shown in FIG. 27, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum 20 is controlled. As a result, the vertical section of the tantalum film 20 obtained by the etching process may be tapered-shaped. When the thin film diode 8 is formed in the foregoing manner using the tantalum film 20 formed by this method, the vertical section, having such a structure that the upper layer film 4 is more likely to be overlapped, is obtained shown in FIG. 47. The Eleventh Manufacturing Method! The eleventh manufacturing method for the thin film diode of the present invention will be described. First, as shown in FIG. 22, the tantalum film 20 of 50 to 500 nm thickness, which serves as the lower layer film material, is formed on the glass substrate 1 by the sputtering technique. Subsequently, the pattern of the resist 6a having the same pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. The dry etching process for the tantalum film 20 is performed using the patterned resist 6a as an etching mask, thereby forming the pattern of the lower layer film 2 as shown in FIG. 37. Either the dry or wet etching processes for the tantalum film 20 is performed in the same manner as in each of the foregoing manufacturing methods. Subsequently, as shown in FIG. 38, the tantalum film 7', which serves as the insulating film material, of the same material as that of the lower layer film 2, is formed on the entire surfaces of the glass substrate 1 and the resist 6a using the sputtering technique. It is noted that the thickness of the tantalum film 7' formed in the process of FIG. 38 is made less than half of that of the anodic oxidation film. As shown in FIG. 39, the resist 6a on the lower layer film 2 as well as the tantalum film 7' thereon is removed. Next, the glass substrate 1 and the tantalum film 7' on the lower layer film 2 are oxidized by the anodic oxidation technique so that the insulating film 3 is formed as shown in FIG. 42. Thereafter, the steps from the formation of the upper layer film 4 to the completion of the thin film diode 8 shown in FIG. 45 are the same as those of the tenth manufacturing method. The Twelfth Manufacturing Method! The twelfth manufacturing method for the thin film diode of the present invention will be described. In this manufacturing method, first, the tantalum film 20 of 50 to 500 nm thickness serving as the lower layer film is formed on the glass substrate 1 by the sputtering technique as shown in FIG. 22. The pattern of the resist 6a having the same pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Next, as shown in FIG. 48, either the dry etching process or the wet etching process for the tantalum film 20 is performed using the resist 6a as a mask. The etching process proceeds until the tantalum film 20 is etched by the predetermined value in the thickness direction. It should be noted that the foregoing predetermined value is the thickness of the tantalum film 20 left after the etching of the film 20 on the glass substrate 1, which must be less than half of the thickness of the anodic oxidation film to be formed later by the anodic oxidation technique. When the etching of the tantalum film 20 is carried out by the dry etching process, the flow rate of the sulfur hexafluoride among the etching conditions is increased. Staying of fluoride free radicals in the vicinity of the pattern of the resist 6a is made easy to maintain. The concentration of the sulfur hexafluoride is increased partially to enhance the etching speed. For this reason, the vertical section obtained by etching the tantalum film 20 presents such a shape that the edge portion of the pattern of the resist 6a is more deeply etched than the other portion as shown in FIG. 48. Further, when the etching process for the tantalum film 20 is performed by the wet etching technique, it is performed by dipping the glass substrate 1 in the solution in which nitric acid, ammonium fluoride, hydrofluoric acid, and water are blended in a 7:2:1:3 ratio. At the time of transferring the glass substrate 1 into a washing bath after lifting the substrate 1 from the solution, if an interval between lifting the substrate 1 from the solution and transferring the substrate 1 into the washing bath, i.e., the waiting time, is made, the etchant is likely to stay in the vicinity of the pattern of the resist 6a. The portion where the etchant stays is etched faster than other portions so that the vertical section also presents such shape that the edge portion of the pattern of the resist 6a is more deeply etched than the other portion as shown in FIG. 48. Next, as shown in FIG. 48, the resist 6a is peeled off, then the insulating film 3 is formed by oxidizing the surface of the tantalum film 20 with the anodic oxidation technique. At the same time, the lower layer film 2 is patterned. At this time, since the thickness of the tantalum film 20 in the vicinity of the lower layer film 2 is thinner than in the other portion thereof, the oxidation is stopped earlier than the central portion between the lower layer films 2. This produces the unoxidized portion 10 at the center portion of the tantalum film 20. Further, as shown in FIG. 50, the indium-tin-oxide (ITO) film 4a serving as the upper layer film is formed on the insulating film 3 by the sputtering technique. Thereafter, the pattern of the resist 6c having the same pattern as the upper layer film is formed on the indium tin oxide film 4a by the photo-lithography technique. As shown in FIG. 51, using the pattern of the resist 6c as an etching mask, the upper layer film 4 is patterned by etching the indium tin oxide film 4a with either the dry etching process or the wet etching process. Thereafter, the insulating film 3 is etched using the pattern of the upper layer film 4 as an etching mask by either the dry etching process or the wet etching process. Thus, the thin film diode 8 is formed free from the breaking of the upper layer film 4 as shown in FIG. 52. The etching process for the insulating film 3 may be performed after peeling off the resist 6c used for formation of the pattern of the upper layer film 4, or it may be performed without peeling off the resist 6c and then the resist 6 may be peeled off. The dry etching process for the insulating film 3 is performed under the same conditions as those of the dry etching process for the tantalum film 20 described above. Further, as shown in FIG. 43, at the time of the etching of the tantalum film 20 serving as the lower layer film, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum 20 is controlled. As a result, the vertical section of the tantalum film 20 obtained by the etching process may be taper-shaped as shown in FIG. 46. In this case, the finally obtained thin film diode 8 is shown in FIG. 53. The thin film diode 8 has such a structure that the upper layer film 4 is more likely to be overlapped. The Thirteenth Manufacturing Method! The thirteenth manufacturing method for the thin film diode of the present invention will be described. First, the structure composed of the patterned lower layer film 2 and the insulating film 3 which are formed on the glass substrate 1 can be obtained using the same method as the foregoing method, as shown in FIG. 49. Further, as shown in FIG. 50, the indium tin oxide (ITO) film 4a serving as the upper layer film is formed on the insulating film 3 by the sputtering technique. Thereafter, the pattern of the resist 6c having the same pattern as that of the upper layer film is formed on the indium tin oxide film 4a by the photo-lithography technique. Further, as shown in FIG. 51, the upper layer film 4 is patterned by either the dry etching technique or the wet etching technique using the resist 6c as an etching mask. Either the dry etching process or the wet etching process for the indium tin oxide film 4a is performed in the same manner as each of the foregoing manufacturing methods. Further, the resist 6c on the patterned upper layer film 4 is peeled off. As shown in FIG. 54, the pattern of the resist 6d, larger than that of the upper layer film 4, is formed. The insulating film 3 is etched by the dry etching technique using the resist 6d as an etching mask. Thus, the thin film diode 8, which has the structure shown in FIG. 55, free from the breaking of the upper layer film 4, can be formed. The dry etching process for the insulating film 3 is performed under the same conditions as that of the dry etching process for the foregoing tantalum film 20. The Fourteenth Manufacturing Method! The fourteenth manufacturing method of the thin film diode of the present invention will be described. Also in this manufacturing method, the pattern of the lower layer film 2 and the insulating film 3 as shown in FIG. 49 are formed on the glass substrate 1 in the same method as those of the foregoing twelfth and thirteenth manufacturing methods. Further, as shown in FIG. 50, the indium-tin-oxide (ITO) film 4a which is an upper layer film material is formed on the insulating film 3 using the sputtering technique. The pattern of the resist 6c which is the same as that of the upper layer film is formed on the indium-tin-oxide film 4a by the photo-lithography technique. As shown in FIG. 51, the pattern of the upper layer film 4 is formed using the pattern of the resist 6c as an etching mask by either the dry etching technique or the wet etching technique. Either the dry etching processing or the wet etching processing for the indium-tin-oxide film 4a, which is an upper layer film material, is carried out in the same manner as in those of the foregoing manufacturing methods. Thereafter, the resist 6c on the patterned upper layer film 4 is peeled off, thereby forming the pattern of the protection film 5 having the larger pattern dimension than that of the upper layer film 4 is formed as shown in FIG. 56. Subsequently, the insulating film 3 is etched using the pattern of the protection film 5 as an etching mask using the dry etching technique, thereby completing the thin film diode 8 as shown in FIG. 57. In this manufacturing method, the dry etching processing for the insulating film 3 is carried out under the same conditions as those of the foregoing dry etching processing for the tantalum film 20. The Fifteenth Manufacturing Method! The fifteenth manufacturing method for the thin film diode of the present invention will be described. Also in this case, the pattern of the lower layer film 2 and the insulating film 3, shown in FIG. 49, are formed on the glass substrate 1 by using the same method as that of the twelfth and thirteenth methods. As shown in FIG. 58, the pattern of the resist 6b having a larger pattern dimension than that of the patterned lower layer film 2 is formed by the photo-lithography technique. Next, the insulating film 3 is etched using the patterned resist 6b as an etching mask by the dry etching technique. And, then the resist 6b on the insulating film 3 is peeled off, thereby obtaining the structure shown in FIG. 59. The dry etching process for the insulating film 3 is performed under the same conditions as those of the foregoing dry etching process for the tantalum film 20. Thereafter, the indium-tin-oxide (ITO) film 4a serving as the upper layer film material is formed on the insulating film 3 and the glass substrate 1 by the sputtering technique. The pattern of the resist having the same pattern as that of the upper layer film on the indium-tin-oxide film 4a by the photo-lithography technique. The indium-tin-oxide film 4a is etched using the resist as an etching mask by either the dry etching technique or the wet etching technique. By etching the film 4a, the pattern of the upper layer film 4 is formed as shown in FIG. 60. As a result, the thin film diode 8 free from the breaking of the upper layer film 4 can be completed. Further, in the situation shown in FIG. 22, at the time of the etching of the tantalum film 20 serving as the lower layer film, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum 20 is controlled. As a result, the vertical section of the tantalum film 20 obtained by the etching process may be tapered-shaped. In this case, the finally obtained thin film diode 8 is shown in FIG. 61. The thin film diode 8 has such a structure that the upper layer film 4 is more likely to be overlapped. The Sixteenth Manufacturing Method! The sixteenth manufacturing method for the thin film diode of the present invention will be described. In this manufacturing method, as shown in FIG. 27, the tantalum film 20 of 100 to 500 nm thickness, which is the lower layer film material, is formed on the glass substrate 1 by the sputtering technique as shown in FIG. 27. The pattern of the resist 6a having the pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Either the dry etching process or the wet etching process to etch the tantalum film 20 using the patterned resist 6a as an etching mask is performed, thereby forming the pattern of the lower layer film 2 as shown in FIG. 28. As shown in FIG. 62, after peeling off the resist 6a on the lower layer film 2, the tantalum film 7 of the same material as that of the lower layer film 2, which is the insulating film material, is again formed on the pattern of the lower layer film 2 and the glass substrate 1 by the sputtering technique. At the time of the formation of the film 7, if the pressure in a sputtering device is lowered, the mean free path of tantalum atoms is lengthened so that the thickness of the portion of the film 7 in the vicinity of the lower layer film 2 is thin due to the influence of the pattern. As a result, the vertical section shown in FIG. 62 can be obtained. In the formation of the film 7, it should be noted that the thickness of the film 7 is less than half of that of the anodic oxidation film. Subsequently, as shown in FIG. 49, the insulating film 3 is formed by oxidizing the surface of the tantalum film 7 with the anodic oxidation technique. Further, as shown in FIG. 50, the indium-tin-oxide (ITO) film 4a, which is the upper layer film material, is formed on the insulating film by the sputtering technique. Thereafter, the pattern of the resist 6a having the same pattern as that of the upper layer film 4 is formed on the indium-tin-oxide film 4a by the photo-lithography technique. As shown in FIG. 51, the pattern of the upper layer film 4 is formed by etching the indium tin oxide film 4a with either the dry etching technique or the wet etching technique, using the pattern of the resist 6c as an etching mask. Further, as shown in FIG. 52, the thin film diode 8 can be completed by etching, using the upper layer film 4 as an etching mask, the insulating film 3 and the anodic un-oxidation portion 10 with the dry etching technique. The dry etching process for the insulating film 3 and the anodic unoxidized portion 10 is performed under the same conditions as those of the foregoing dry etching process for the tantalum film 20. Further, in the situation shown in FIG. 27, at the time of the etching of the tantalum film 20 which is the lower layer film, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum 20 is controlled. As a result, the vertical section of the lower layer film 2 obtained by the etching process may be taper-shaped. In this case, the finally obtained thin film diode 8 is shown in FIG. 53. The thin film diode 8 has such a structure that the upper layer film 4 is more likely to be overlapped as shown in FIG. 61. The Seventeenth Manufacturing Method! The seventeenth manufacturing method for the thin film diode of the present invention will be described. In this manufacturing method, as shown in FIG. 22, the tantalum film 20 of 100 to 500 nm thickness, which is the lower layer film material, is formed on the glass substrate 1 by the sputtering technique. The pattern of the resist 6a having the pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Either the dry etching process or the wet etching process to etch the tantalum film 20 using the patterned resist 6a as an etching mask is performed, thereby forming the pattern of the lower layer film 2 as shown in FIG. 37. As shown in FIG. 63, the tantalum film 7 of the same material as that of the lower layer film 2, which is the insulating film material, is formed by the sputtering technique. At the time of the formation of the film 7, if the pressure in the sputtering device is lowered, the mean free path of tantalum atoms is lengthened so that the thickness of the portion of the film 7 in the vicinity of the lower layer film 2 is thin due to the influence of the pattern. As a result, the vertical section shown in FIG. 63 can be obtained. In the formation of the film 7, it should be noted that the thickness of the film 7 is less than half of that of the anodic oxidation film. For example, the thickness of the film 7 is less than 100 nm, when the thickness of the anodic oxidation film is 200 nm. Next, as shown in FIG. 64, the resist 6a is peeled off as well as the tantalum film 7 thereon. The insulating film 3 is formed on the upper layer film 2 by oxidizing the surfaces of the lower layer film 2 and the tantalum film 7 with the anodic oxidation technique, as shown in FIG. 49. At this time, since the thickness of the portion of the tantalum film 7 in the vicinity of the lower layer film 2 is thinner than at other portions thereof, the growth of the oxide film is stopped earlier than the central portion between the lower layer films 2 and 2. This produces the unoxidized portion 10 at the center portion of the tantalum film 7. Next, as shown in FIG. 58, the pattern of the resist 6b having a larger pattern dimension than that of the lower layer film 2 is formed on the insulating film 3. After etching the insulating film 3 using the patterned resist 6b as an etching mask with the dry etching technique, the resist 6b on the insulating film 3 is peeled off. As a result, the vertical section shown in FIG. 59 is obtained. The dry etching processing for the insulating film 3 and the unoxidized portion 10 is carried out under the same conditions as those of the foregoing dry etching processing for the tantalum film 20. Thereafter, the indium-tin-oxide (ITO) film 4a, which is the upper layer film material, is formed on the insulating film 3 by the sputtering technique. The pattern of the resist having the same pattern dimension as that of the upper layer film is formed on the indium-tin-oxide film 4a by the photo-lithography technique. The pattern of the upper layer film 4 is formed by etching the indium-tin-oxide film 4a using the pattern of the resist with either the dry etching technique or the wet etching technique, and the thin film diode 8 can be completed as shown in FIG. 60. Further, in the situation shown in FIG. 22, at the time of the etching of the tantalum film 20 which is the lower layer film, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum 20 is controlled. As a result, the vertical section of the lower layer film 2 obtained by the etching process may be tapered-shaped. In this case, the finally obtained thin film diode 8 is shown in FIG. 61. The thin film diode 8 has such a structure that the upper layer film 4 is more likely to be overlapped. The Eighteenth Manufacturing Method! The eighteenth manufacturing method for the thin film diode of the present invention will be described. First, as shown in FIG. 27, the tantalum film 20 of 50 to 500 nm thickness, which is the lower layer film material, is formed on the glass substrate 1 by the sputtering technique. The pattern of the resist 6a having the pattern as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Either the dry etching process or the wet etching process to etch the tantalum film 20 using the patterned resist 6a as an etching mask is performed, thereby forming the pattern of the lower layer film 2 as shown in FIG. 28. Next, as shown in FIG. 62, the tantalum film 7, which is the insulating film material of the same material as that of the lower layer film 2, is formed on the glass substrate 1 and the pattern of the lower layer film 2 by the sputtering technique. At the time of the formation of the film 7, if the pressure in the sputtering device is lowered, the mean free path of tantalum atoms is lengthened so that the thickness of the portion of the film 7 in the vicinity of the lower layer film 2 is thin due to the influence of the pattern. As a result, the vertical section shown in FIG. 62 can be obtained. In the formation of the film 7, it should be noted that the thickness of the film 7 is less than half of that of the anodic oxidation film. For example, when the thickness of the anodic oxidation film is required to be 200 nm, the thickness of the tantalum film 7 should be less than 100 nm. The insulating film 3 is formed on the lower layer film 2 by oxidizing the tantalum film 7 with the anodic oxidation technique, as shown in FIG. 49. At this time, since the thickness of the portion of the tantalum film 7 in the vicinity of the lower layer film 2 is thinner than at other portions thereof, the growth of the oxide film is stopped earlier than the central portion between the lower layer films 2 and 2. This produces the unoxidized portion 10 at the center portion of the tantalum film 7. Further, as shown in FIG. 50, the indium-tin-oxide (ITO) film 4a which is the upper layer film material is formed on the insulating film 3 by the sputtering technique. The pattern of the resist 6c having the same pattern dimension as that of the upper layer film is formed on the indium-tin-oxide film 4a by the photo-lithography technique. Thereafter, as shown in FIG. 51, the pattern of the upper layer film 4 is formed by etching the indium tin oxide film 4a using the pattern of the resist 6c as an etching mask with either the dry etching technique or the wet etching technique. Subsequently, the thin film diode 8 is completed by etching the insulating film 3 using the pattern of the upper layer film 4 as an etching mask with the dry etching technique, as shown in FIG. 52. The etching of the insulating film 3 may be performed after peeling off the resist 6c used for the formation of the pattern of the upper layer film 4, or, it may be performed prior to peeling off the resist 6c. Further, in the situation shown in FIG. 27, at the time of the etching of the tantalum film 20 which is the lower layer film, by regulating the flow rate of oxygen, the etching rate of the resist 6a to the tantalum 20 is controlled. As a result, the vertical section of the lower layer film 2 obtained by etching process may be tapered-shaped. In this case, the finally obtained thin film diode 8 is shown in FIG. 53. The thin film diode 8 has such a structure that the upper layer film 4 is more likely to be overlapped. The Nineteenth Manufacturing Method! The nineteenth manufacturing method for the thin film diode of the present invention will be described. The pattern of the upper layer film and the insulating film 3 are formed on the glass substrate 1 using any of the above described manufacturing methods as shown in FIG. 49. Subsequently, the indium-tin-oxide (ITO) film 4a which is an upper layer film material is formed on the insulating film 3 by the sputtering technique as shown in FIG. 50. The pattern of the resist 6c having the same pattern dimension as that of the upper layer film is formed on the indium-tin-oxide film 4a by the photo-lithography technique. As shown in FIG. 51, the pattern of the upper layer film 4 is formed by etching the indium tin oxide film 4a using the pattern of the resist 6c as an etching mask with either the dry etching technique or the wet etching technique. Further, the resist 6c on the pattern of the upper layer film 4 is peeled off, and as shown in FIG. 54, the pattern of the resist 6d, having the larger pattern dimension than that of the upper layer film 4, is formed. Thereafter, using the resist 6d as an etching mask, the insulating film 3 is etched by the dry etching technique. The resist 6d is peeled off from the insulating film 3 so that the thin film diode 8 can be completed as shown in FIG. 55. The Twentieth Manufacturing Method! The twentieth manufacturing method for the thin film diode of the present invention will be described. Also in this case, the pattern of the lower layer film 2 and the insulating film 3 are formed on the glass substrate 1 using any of the foregoing manufacturing methods as shown in FIG. 49. Subsequently, as shown in FIG. 50, the indium tin oxide film 4a which is a upper layer film material is formed on the insulating film 3 by the sputtering technique. The pattern of the resist 6c having the same pattern dimension as that of the upper layer film is formed on the indium tin oxide film 4a by the photo-lithography technique. Then, the pattern of the upper layer film 4 is formed by etching the indium tin oxide film 4a using the pattern of the resist 6c as an etching mask with either the dry etching technique or the wet etching technique as shown in FIG. 51. Further, the resist 6c on the upper layer film is peeled off. The pattern of the protection film 5 having the larger pattern dimension than that of the upper layer film 4 as shown in FIG. 56. Next, the insulating film 3 is etched using the pattern of the protection film 5 as an etching mask by the dry etching technique, thereby completing the manufacture of the thin film diode 8 as shown in FIG. 57. The Twenty-first Manufacturing Method! The twenty-first manufacturing method for the thin film diode of the present invention will be described. In this manufacturing method of the present invention, first, as shown in FIG. 22, the tantalum film 20 of 50 to 500 nm thickness which is a lower layer material is formed on the glass substrate 1 by the sputtering technique. Then, the pattern of the resist 6a having the same pattern dimension as that of the lower layer film is formed on the tantalum film 20 by the photo-lithography technique. Subsequently, either the dry etching process or the wet etching process for the tantalum film 20 which is the lower layer film material is performed using the patterned resist 6a as an etching mask. Thus, the pattern of the lower layer film 2 is formed as shown in FIG. 28. Thereafter, as shown in FIG. 63, the tantalum film 7 which is the same insulating film material as that of the lower layer film 2 is formed on the glass substrate 1 and the pattern of the lower layer film 2 by the sputtering technique. At the time of the formation of the film 7, if the pressure in the sputtering device is lowered, the mean free path of tantalum atoms is lengthened so that the thickness of the portion of the film 7 in the vicinity of the lower layer film 2 is thin due to the influence of the pattern. As a result, the vertical section shown in FIG. 63 can be obtained. In the formation of the film 7, it should be noted that the thickness of the film 7 is less than half of that of the anodic oxidation film. For example, when the thickness of the anodic oxidation film is required to be 200 nm, the thickness of the tantalum film 7 should be less than 100 nm. Thereafter, the resist 6a on the pattern of the lower layer film 2 and the tantalum film 7 are peeled off. As shown in FIG. 49, the surfaces of the lower layer film 2 and the tantalum film 7 are oxidized by the anodic oxidation technique, thereby forming the insulating film 3 on the entire surface of the resultant structure. As shown in FIG. 50, the indium tin oxide film 4a which is a upper layer film material is formed on the insulating film 3 by the sputtering technique. Then, the pattern of the resist 6c having the same pattern dimension as that of the upper layer film is formed on the indium tin oxide film 4a by the photo-lithography technique. Further, as shown in FIG. 51, the indium tin oxide film 4a is etched using the pattern of the resist 6c as an etching mask by either the dry etching technique or the wet etching technique, thereby forming the pattern of the upper layer film 4. Finally, the thin film diode 8 can be obtained by etching the insulating film 3 using the pattern of the upper layer film 4 as an etching mask with the dry etching technique as shown in FIG. 52. Etching of the insulating film 3 may be performed after peeling off the resist 6c used for the formation of the upper layer film 4, or it may be performed prior to the peeling off the resist 6c. The Twenty-second Manufacturing Method! The twenty-second manufacturing method for the thin film diode of the present invention will be described. Also in this case, the pattern of the lower layer film 2 and the insulating film 3 are formed on the glass substrate 1 using any of the foregoing manufacturing methods as shown in FIG. 49. Subsequently, as shown in FIG. 50, the indium tin oxide film 4a which is a upper layer film material is formed on the insulating film 3 by the sputtering technique. Thereafter, the pattern of the resist 6c having the same pattern dimension as that of the upper layer film is formed on the indium tin oxide film 4a by the photo-lithography technique. Then, the pattern of the upper layer film 4 is formed by etching the indium tin oxide film 4a using the pattern of the resist 6c as an etching mask with either the dry etching technique or the wet etching technique as shown in FIG. 51. Further, the resist 6c on the pattern of the upper layer film 4 is peeled off. The pattern of the resist 6d having the larger pattern dimension than that of the pattern of the upper layer film 4 is formed as shown in FIG. 54. Finally, the insulating film 3 is etched using the pattern of the resist 6d as an etching mask by the dry etching technique, thereby completing the manufacture of the thin film diode 8 free from the breaking of the upper layer film 4 as shown in FIG. 55. In the manufacturing method including the step for forming an insulating film material on the pattern of a lower layer film among various kinds of manufacturing methods for manufacturing a thin film diode of the present invention, a material which is available for forming the insulating film by an anodic oxidation process may be used. Therefore, such material, for example, aluminum (Al) film instead of a tantalum film used in each of the foregoing manufacturing methods may be adopted as the insulating film material. In this case, an etching process for the aluminum film is performed using a solution in which phosphoric acid, hydrochloric acid, acetic acid, and water are blended in a 5:1:2:3 ratio. As is apparent from the above description, according to the manufacturing methods of the thin film diode incorporated in the liquid crystal display device of the present invention, in each of the manufacturing methods an upper layer film is easily overlapped with the lower layer film, and quality differences between the element region of the thin film diode and the vicinity thereof are not present. Therefore, the defective elements due to breakage of the step portion are greatly decreased so that the display quality of the liquid crystal display device can be remarkably enhanced. Further, according to the manufacturing method including the step for reducing the pattern dimension of the resist by an ashing process at the time of patterning the lower layer film, the pattern dimension of the thin film diode can be reduced smaller than that of the pattern formed by a photo-lithography technique. Therefore, miniaturization of the thin film diode (active element) which can not achieved by the photo-lithography technique is possible.

4y

PRIORITY INFORMATION [0001] This application claims the priority benefit under 35 U.S.C. §120 to U.S. patent application Ser. No. 12/487,535 (filed 18 Jun. 2009), which claims the priority benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application Ser. No. 61/106,096 (filed 16 Oct. 2008), the entirety of which is hereby expressly incorporated by reference herein. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to coordinate measurement machines and, more particularly, to coordinate measurement machines with laser scanners. [0004] 2. Description of the Related Art [0005] Rectilinear measuring systems, also referred to as coordinate measuring machines (CMMs) and articulated arm measuring machines, are used to generate highly accurate geometry information. In general, these instruments capture the structural characteristics of an object for use in quality control, electronic rendering and/or duplication. One example of a conventional apparatus used for coordinate data acquisition is a portable coordinate measuring machine (PCM_M), which is a portable device capable of taking highly accurate measurements within a measuring sphere of the device. Such devices often include a probe mounted on an end of an arm that includes a plurality of transfer members connected together by joints. The end of the arm opposite the probe is typically coupled to a moveable base. Typically, the joints are broken down into singular rotational degrees of freedom, each of which is measured using a dedicated rotational transducer. During a measurement, the probe of the arm is moved manually by an operator to various points in the measurement sphere. At each point, the position of each of the joints must be determined at a given instant in time. Accordingly, each transducer outputs an electrical signal that varies according to the movement of the joint in that degree of freedom. Typically, the probe also generates a signal. These position signals and the probe signal are transferred through the arm to a recorder/analyzer. The position signals are then used to determine the position of the probe within the measurement sphere. See e.g., U.S. Pat. Nos. 5,829,148 and 7,174,651, which are incorporated herein by reference in their entireties. [0006] Increasingly, PCMM's are used in combination with an optical or laser scanner. In such applications the optical or laser scanner typically includes an optics system, a laser or light source, sensors and electronics that are all housed in one box. The laser scanner box is then, in turn, coupled to the probe end of the PCMM and to a side of the probe. The various locations that existed for mounting the laser scanning box include positioning the box on top of the probe, forward and below the axis of the probe, and/or off to the side of the probe. In this manner, 2-dimensional and/or 3-dimensional data could be gathered with the laser scanner and combined with the position signals generated by the PCMM. See e.g., U.S. Pat. No. 7,246,030. [0007] While such PCMM and laser scanner combinations have been useful. As mentioned above, the purpose of PCMM's is to take highly accurate measurements. Accordingly, there is a continuing need to improve the accuracy of such devices. SUMMARY OF THE INVENTION [0008] One aspect of the present invention is the realization that such prior art systems suffer from a number of inefficiencies. For example, prior art systems typically require a repeatable kinematic mount that would allow the laser scanner to be easily removed and replaced from the arm. Such mounts are generic so that many different types of scanners can be mounted to the same CMM. These generic mounts place the laser scanner in non-optimal locations which results in less accurate laser scanning performance The various locations that existed for mounting the laser scanning box were on top of the last axis, forward and below the last axis, or off to the side of the last axis, as discussed further below. [0009] Accordingly, one embodiment of the present invention comprises an optical position acquisition member. The member can include a base plate that has an opening configured to receive a CMM measuring probe. A laser and an optical sensor can both mount on the plate such that the sensor is generally collinear with the laser and the opening, with the opening between the laser and the sensor. [0010] In another embodiment, an articulated arm CMM is provided. The articulated arm can include a plurality of articulated arm members, a measuring probe, a receiving portion at a distal end, and a base at a proximal end. A base plate can mount on the receiving portion and include a hole positioned such that the measuring probe passes through the hole when mounted. The base plate can couple to a laser and an optical sensor located on opposite sides of the hole. [0011] In yet another embodiment, a coordinate measurement device includes an articulated arm and a laser scanner assembly. The articulated arm can have a first end, a second end, and a plurality of jointed arm segments therebetween. Each arm segment can define at least one axis of rotation of the articulated arm, and a last axis of the arm can be defined by bearings near a distal end of the arm. The laser scanner assembly can couple to the second end of the arm and be rotatable about the last axis of rotation of the articulated arm. Additionally, the laser scanner assembly can include a laser and an image sensor, the laser positioned on an opposite side of the last axis of rotation from the image sensor. Further, at least one of the laser and image sensor can overlap the bearings. [0012] All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed. In addition, the individual embodiments need not provide all or any of the advantages described above. BRIEF DESCRIPTION OF THE DRAWINGS [0013] Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying figures showing illustrative embodiments of the invention, in which: [0014] FIG. 1 is a perspective view of an embodiment CMM arm with a laser scanner; [0015] FIG. 1A is a side view of the CMM arm of FIG. 1 ; [0016] FIG. 1B is a top view of the CMM arm of FIG. 1 ; [0017] FIG. 2 is a perspective view of a coordinate acquisition member of the CMM arm of FIG. 1 ; [0018] FIG. 2A is a side view of the coordinate acquisition member of FIG. 2 ; [0019] FIG. 2B is a top view of the coordinate acquisition member of FIG. 2 ; [0020] FIG. 2C is a side cross-sectional view of the coordinate acquisition member of FIG. 2 , at 2 C- 2 C; [0021] FIG. 2D is a side outline view of the coordinate acquisition member of FIG. 2 , indicating various dimensions; [0022] FIG. 3 is an exploded side view of the coordinate acquisition member of FIG. 2 ; [0023] FIG. 3A is a back view of a non-contact coordinate detection device of FIG. 3 , at 3 A- 3 A; [0024] FIG. 3B is a front view of a main body of a coordinate acquisition member of FIG. 3 , at 3 B- 3 B; [0025] FIG. 4A depicts an alternative coordinate acquisition member; [0026] FIG. 4B depicts a side outline view of the coordinate acquisition member of FIG. 4A , indicating various dimensions; [0027] FIG. 5A depicts an alternative coordinate acquisition member; [0028] FIG. 5B depicts a side outline view of the coordinate acquisition member of FIG. 5A , indicating various dimensions; [0029] FIG. 6A depicts an alternative coordinate acquisition member; [0030] FIG. 6B depicts a side outline view of the coordinate acquisition member of FIG. 6A , indicating various dimensions; [0031] FIG. 7A depicts an alternative coordinate acquisition member; [0032] FIG. 7B depicts a side outline view of the coordinate acquisition member of FIG. 7A , indicating various dimensions; and [0033] FIG. 7C depicts a front outline view of the coordinate acquisition member of FIG. 7A , indicating various dimensions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0034] FIGS. 1-1B illustrate one embodiment of a portable coordinate measuring machine (PCMM) 1 in accordance with the present invention. In the illustrated embodiment, the PCMM 1 comprises a base 10 , a plurality of rigid transfer members 20 , a coordinate acquisition member 50 and a plurality of articulation members 30 - 36 connecting the rigid transfer members 20 to one another. Each articulation member 30 - 36 is configured to impart one or more rotational and/or angular degrees of freedom. Through the various articulation members 30 - 36 , the PCMM 1 can be aligned in various spatial orientations thereby allowing fine positioning and orientating of the coordinate acquisition member 50 in three dimensional space. [0035] The position of the rigid transfer members 20 and the coordinate acquisition member 50 may be adjusted using manual, robotic, semi-robotic and/or any other adjustment method. In one embodiment, the PCMM 1 , through the various articulation members 30 , is provided with seven rotary axes of movement. It will be appreciated, however, that there is no strict limitation to the number of axes of movement that may be used, and fewer or additional axes of movement may be incorporated into the PCMM design. [0036] In the embodiment PCMM 1 illustrated in FIG. 1 , the articulation members 30 - 36 can be divided into two functional groupings based on their operation, namely: 1) those articulation members 30 , 32 , 34 , 36 which allow the swiveling motion associated with a specific transfer member (hereinafter, “swiveling joints”), and 2) those articulation members 31 , 33 , 35 which allow a change in the relative angle formed between two adjacent members or between the coordinate acquisition member 30 and its adjacent member (hereinafter, “hinge joints”). While the illustrated embodiment includes four swiveling joints and three hinge joints positioned as to create seven axes of movement, it is contemplated that in other embodiments, the number of and location of hinge joints and swiveling joints can be varied to achieve different movement characteristics in a PCMM. For example, a substantially similar device with six axes of movement could simply lack the swivel joint 30 between the coordinate acquisition member 50 and the adjacent articulation member 20 . In still other embodiments, the swiveling joints and hinge joints can be combined and/or used in different combinations. [0037] In various embodiments, the coordinate acquisition member 50 comprises a contact sensitive member 55 (depicted as a hard probe) configured to engage the surfaces of a selected object and generate coordinate data on the basis of probe contact, as depicted in FIGS. 2-3 . In the illustrated embodiment, the coordinate acquisition member 50 also comprises a non-contact scanning and detection component that does not necessarily require direct contact with the selected object to acquire geometry data. As depicted, the non-contact scanning device comprises a non-contact coordinate detection device 60 (shown as a laser coordinate detection device/laser scanner) that may be used to obtain geometry data without direct object contact. It will be appreciated that various coordinate acquisition member configurations including: a contact-sensitive probe, a non-contact scanning device, a laser-scanning device, a probe that uses a strain gauge for contact detection, a probe that uses a pressure sensor for contact detection, a device that uses an infrared beam for positioning, and a probe configured to be electrostatically-responsive may be used for the purposes of coordinate acquisition. Further, in some embodiments, a coordinate acquisition member 50 can include one, two, three, or more than three coordinate acquisition mechanisms. [0038] With particular reference to FIG. 3 , in various embodiments of the PCMM 1 , the various devices which may be used for coordinate acquisition, such as the laser coordinate detection device 60 , may be configured to be manually disconnected and reconnected from the PCMM 1 such that an operator can change coordinate acquisition devices without specialized tools. Thus, an operator can quickly and easily remove one coordinate acquisition device and replace it with another coordinate acquisition device. Such a connection may comprise any quick disconnect or manual disconnect device. This rapid connection capability of a coordinate acquisition device can be particularly advantageous in a PCMM 1 that can be used for a wide variety of measuring techniques (e.g. measurements requiring physical contact of the coordinate acquisition member with a surface followed by measurements requiring only optical contact of the coordinate acquisition member) in a relatively short period of time. Although, as depicted, only the laser coordinate detection device 60 is removed, in some embodiments the contact sensitive member 55 can also be removed and replaced in a similar manner. [0039] In the embodiment of FIG. 2 , the coordinate acquisition member 30 also comprises buttons 41 , which are configured to be accessible by an operator. By pressing one or more of the buttons 41 singly, multiply, or in a preset sequence, the operator can input various commands to the PCMM 1 . In some embodiments the buttons 41 can be used to indicate that a coordinate reading is ready to be recorded. In other embodiments the buttons 41 can be used to indicate that the location being measured is a home position and that other positions should be measured relative to the home position. In other embodiments the buttons 41 may be used to record points using the contact sensitive member 55 , record points using the non-contact coordinate detection device 60 , or to switch between the two devices. In other embodiments, the buttons 41 can be programmable to meet an operator's specific needs. The location of the buttons 41 on the coordinate acquisition member 50 can be advantageous in that an operator need not access the base 10 or a computer in order to activate various functions of the PCMM 1 while using the coordinate acquisition member 50 . This positioning may be particularly advantageous in embodiments of PCMM having transfer members 20 that are particularly long, thus placing the base 10 out of reach for an operator of the coordinate acquisition member 50 in most positions. In some embodiments of the PCMM 1 , any number of operator input buttons (e.g., more or fewer than the two illustrated), can be provided. Advantageously, as depicted the buttons 61 are placed on the handle 40 in a trigger position, but in other embodiments it may be desirable to place buttons in other positions on the coordinate acquisition member 50 or anywhere on the PCMM 1 . Other embodiments of PCMM can include other operator input devices positioned on the PCMM or the coordinate acquisition member 50 , such as switches, rotary dials, or touch pads in place of, or in addition to operator input buttons. [0040] With particular reference to FIG. 1 , in some embodiments, the base 10 can be coupled to a work surface through a magnetic mount, a vacuum mount, bolts or other coupling devices. Additionally, in some embodiments, the base 10 can comprise various electrical interfaces such as plugs, sockets, or attachment ports. In some embodiments, attachment ports can comprise connectability between the PCMM 1 and a USB interface for connection to a processor such as a general purpose computer, an AC power interface for connection with a power supply, or a video interface for connection to a monitor. In some embodiments, the PCMM 1 can be configured to have a wireless connection with an external processor or general purpose computer such as by a WiFi connection, Bluetooth connection, RF connection, infrared connection, or other wireless communications protocol. In some embodiments, the various electrical interfaces or attachment ports can be specifically configured to meet the requirements of a specific PCMM 1 . [0041] With continued reference to FIG. 1 , the transfer members 20 are preferably constructed of hollow generally cylindrical tubular members so as to provide substantial rigidity to the members 20 . The transfer members 20 can be made of any suitable material which will provide a substantially rigid extension for the PCMM 1 . The transfer members 20 preferably define a double tube assembly so as to provide additional rigidity to the transfer members 20 . Furthermore, it is contemplated that the transfer 20 in various other embodiments can be made of alternate shapes such as those comprising a triangular or octagonal cross-section. [0042] In some embodiments, it can be desirable to use a composite material, such as a carbon fiber material, to construct at least a portion of the transfer members 20 . In some embodiments, other components of the PCMM 1 can also comprise composite materials such as carbon fiber materials. Constructing the transfer members 20 of composites such as carbon fiber can be particularly advantageous in that the carbon fiber can react less to thermal influences as compared to metallic materials such as steel or aluminum. Thus, coordinate measuring can be accurately and consistently performed at various temperatures. In other embodiments, the transfer members 20 can comprise metallic materials, or can comprise combinations of materials such as metallic materials, ceramics, thermoplastics, or composite materials. Also, as will be appreciated by one skilled in the art, many of the other components of the PCMM 1 can also be made of composites such as carbon fiber. Presently, as the manufacturing capabilities for composites are generally not as precise when compared to manufacturing capabilities for metals, generally the components of the PCMM 1 that require a greater degree of dimensional precision are generally made of a metals such as aluminum. It is foreseeable that as the manufacturing capabilities of composites improved that a greater number of components of the PCMM 1 can be also made of composites. [0043] With continued reference to FIG. 1 , some embodiments of the PCMM 1 may also comprise a counterbalance system 110 that can assist an operator by mitigating the effects of the weight of the transfer members 20 and the articulating members 30 - 36 . In some orientations, when the transfer members 20 are extended away from the base 10 , the weight of the transfer members 20 can create difficulties for an operator. Thus, a counterbalance system 110 can be particularly advantageous to reduce the amount of effort that an operator needs to position the PCMM 1 for convenient measuring. In some embodiments, the counterbalance system 110 can comprise resistance units (not shown) which are configured to ease the motion of the transfer members 20 without the need for heavy weights to cantilever the transfer members 20 . It will be appreciated by one skilled in the art that in other embodiments simple cantilevered counterweights can be used in place or in combination with resistance units. Further, although as depicted there is only one counterbalance system 110 unit, in other embodiments there can be more. [0044] In some embodiments, the resistance units can comprise hydraulic resistance units which use fluid resistance to provide assistance for motion of the transfer members 20 . In other embodiments the resistance units may comprise other resistance devices such as pneumatic resistance devices, or linear or rotary spring systems. [0045] As is known in the art, the position of the contact sensitive member 55 in space at a given instant can be calculated by knowing the length of each rigid transfer member 20 and the specific position of each of the articulation members 30 - 36 . Each of the articulation members 30 - 36 can be broken down into a singular rotational degree of motion, each of which is measured using a dedicated rotational transducer. Each transducer outputs a signal (e.g., an electrical signal), which varies according to the movement of the articulation member in its degree of motion. The signal can be carried through wires or otherwise transmitted to the base 10 . From there, the signal can be processed and/or transferred to a computer for determining the position of the coordinate acquisition member 50 and its various parts in space. [0046] In one embodiment, the transducer can comprise an optical encoder. In general, each encoder measures the rotational position of its axle by coupling is movement to a pair of internal wheels having successive transparent and opaque bands. In such embodiments, light can be shined through the wheels onto optical sensors which feed a pair of electrical outputs. As the axle sweeps through an arc, the output of the analog encoder can be substantially two sinusoidal signals which are 90 degrees out of phase. Coarse positioning can occur through monitoring the change in polarity of the two signals. Fine positioning can be determined by measuring the actual value of the two signals at the instant in question. In certain embodiments, maximum accuracy can be obtained by measuring the output precisely before it is corrupted by electronic noise. Additional details and embodiments of the illustrated embodiment of the PCMM 1 can be found in U.S. Pat. No. 5,829,148, the entirety of which is hereby incorporated by reference herein. [0047] With reference to FIGS. 1 , 1 A, and 1 B, in some embodiments, the PCMM 1 can comprise one or more rotatable grip assemblies 122 , 124 . In the illustrated embodiment, the PCMM 1 can comprise a lower rotatable grip assembly 122 and an upper rotatable grip assembly 124 . Advantageously, having a lower rotatable grip assembly 122 and an upper rotatable grip assembly 124 disposed on a last transfer member 21 , allows the operator to easily use both hands in positioning the PCMM 1 . In other embodiments, the PCMM 1 can comprise one, or more than two rotatable grips. Additional details of the grip assemblies can be found in Applicant's co-pending U.S. patent application Ser. No. 12/057,966, filed Mar. 28, 2008, the entirety of which is hereby incorporated by reference herein [0048] While several embodiments and related features of a PCMM 1 have been generally discussed herein, additional details and embodiments of PCMM 1 can be found in U.S. Pat. Nos. 5,829,148 and 7,174,651, the entirety of these patents being incorporated by reference herein. While certain features below are discussed with reference to the embodiments of a PCMM 1 described above, it is contemplated that they can be applied in other embodiments of a PCMM such as those described in U.S. Pat. No. 5,829,148 or 7,174,651, U.S. patent application Ser. No. 11/963,531, filed Dec. 21, 2007, entitled “IMPROVED JOINT AXIS FOR COORDINATE MEASUREMENT MACHINE”, U.S. patent application Ser. No. 11/943,463, filed Nov. 20, 2007, entitled “COORDINATE MEASUREMENT DEVICE WITH IMPROVED JOINT” and U.S. patent application Ser. No. 11/775,081, filed Jul. 9, 2007, entitled “JOINT FOR COORDINATE MEASUREMENT DEVICE”, the entire contents of these patents and patent applications being incorporated herein by reference. [0049] As depicted in FIG. 1 , the PCMM can include a coordinate acquisition member 50 at an end of its arm. FIGS. 2-3 depict the coordinate acquisition member 50 in more detail. As shown, the coordinate acquisition member 50 can include a contact sensitive member 55 and a laser coordinate detection device 60 facing a front end 54 . The coordinate acquisition member 50 can further attach to a handle 40 at a lower end 51 and the PCMM 1 at a rear end 52 . The coordinate acquisition member 50 can further include a top end 53 . At the rear end 52 , the coordinate acquisition member 50 can further include a data connection (not shown) with the hinge 31 , such as a slip ring connection, a direct wire, or some other connection. This can allow data transfer between the coordinate acquisition member 50 and the PCMM 1 . The PCMM 1 can include similar data transfer elements along its arm, allowing data transmission between the coordinate acquisition member 50 and the base 10 , or any peripheral computing medium external to the PCMM arm. [0050] The laser coordinate detection device 60 can include a light source 65 (depicted as a laser) and an optical sensor 70 (depicted as a camera), and can acquire positional data by a method of triangulation. The laser or light source 65 can create an illuminated laser plane including a laser line L 4 . The camera 70 can be displaced from the laser plane and further be non-parallel to the laser plane. Accordingly, the camera 70 will view points as higher or lower, depending on their position further or closer to the laser 65 . Similarly, the camera 70 will view points illuminated by the laser as being either further to the left or the right, according to their actual position relative to the laser 65 . Comparing the geometric relationship between the position and orientation of the laser 65 and the camera 70 will allow one of skill in the art to appropriately translate the position of the image of the laser-illuminated point in the image captured by the camera 70 to an actual position in space in conjunction with the position of the coordinate acquisition member 50 itself. [0051] In FIG. 1 , a plurality of the axes of movement are marked according to their proximity to the coordinate acquisition member 50 . As depicted, the coordinate acquisition member 50 can pivot about a last axis of rotation L 1 on a swivel 30 . The last axis of rotation L 1 and the swivel 30 are more clearly depicted in FIG. 2C . As shown, the laser coordinate detection device 60 mounts bearings 150 , 151 at an end of the PCMM arm 1 . The orientation and position of the bearings 150 , 151 can substantially define the last axis L 1 . Thus, the laser coordinate detection device 60 can rotate about the last axis L 1 , independent of the contact sensitive member (depicted as a probe) 55 . In some embodiments, the contact sensitive member 55 is not rotatable, reducing potential error from any eccentricity between the contact sensitive member 55 and the last axis L 1 . The swivel 30 can rotate about a second to last axis of rotation L 2 at the end of the last rigid transfer member 21 on a hinge joint 31 . Like the bearings 150 , 151 and the last axis L 1 , the second to last axis L 2 can be substantially defined by a hinge shaft 140 . As depicted, the last axis L 1 can also be considered a roll axis, and the second to last axis can also be considered a pitch axis. Similarly, rotation about a third to last axis L 3 can be considered a yaw axis. [0052] The handle 40 can also generally comprise a pistol-grip style, which can further include ergonomic grooves corresponding to human fingers (not shown). The handle can also have a generally central axis L 5 . Optionally, within the handle 40 , a battery 42 can be held. In some embodiments the handle 40 can include a sealed battery, as described in U.S. Publication No. 2007/0256311A1, published Nov. 8, 2007, which is incorporated by reference herein in its entirety. Further, the battery 42 can insert through the bottom of the handle 40 . In other embodiments, the battery 42 can insert through the top of the handle 40 , and the handle 40 can release from the coordinate acquisition member 50 to expose an opening for battery insertion and removal. The battery can be provided to power the laser scanner, rotational motors about one of the articulation members 30 - 36 , and/or other types of probes or devices. This can reduce current draw through the arm, decrease overall power requirements, and/or reduce heat generated in various parts of the arm. [0053] In one embodiment, data can be transmitted wirelessly to and from either the coordinate acquisition member 50 or the non-contact coordinate detection device 60 and the base of the PCMM 1 or to an external device such as a computer. This can reduce the number of internal wires through the PCMM 1 . It can also reduce the number of wires between the PCMM 1 and the computer. [0054] Above the handle 40 , the coordinate acquisition member 50 can include a main body 90 , best depicted in FIG. 3 . The main body 90 can connect directly to the hinge 31 at the rear end 52 of the coordinate acquisition member 50 . The main body 90 can further hold the contact sensitive member 55 . In preferred embodiments, the main body 90 can even further hold the contact sensitive member 55 in near alignment with the swivel 30 , such that an axis of the contact sensitive member 55 extends near the last axis L 1 of the swivel 30 . In some embodiments, the axis of the contact sensitive member 55 can pass through the last axis L 1 of the swivel 30 . In other embodiments the axis of the contact sensitive member 55 can pass within 10 mm of the last axis L 1 , this distance corresponding to D 3 (depicted in FIG. 2D ). [0055] As best depicted in FIG. 3B , the main body 90 can further include a mounting portion 91 , a recess 92 , and a data port 93 , configured to interact with a laser coordinate detection device (depicted as a laser scanner) 60 . The laser scanner 60 , as best depicted in FIG. 3A , can include an upper housing 80 , a laser 65 , and a data port 101 . As shown in FIG. 3 , the laser scanner 60 can be configured to mount on the main body 90 as an auxiliary body (which can include different devices in other embodiments). The upper housing 80 can be shaped to match the mounting portion 91 , and can accordingly be received by that portion. The recess 92 can be shaped to receive the laser 65 when the mounting portion 91 receives the upper housing 80 . Upon these interactions, the data ports 93 , 101 can interact to pass information between the main body 90 and the laser scanner 60 (and accordingly further along the PCMM arm 1 as described above). The laser coordinate detection device 60 can further include a base-plate 75 . The base-plate 75 can include a port 85 configured to receive the contact sensitive member 55 when the laser scanner 60 mounts to the main body 90 . Additionally, the base-plate 75 can include assembly holes 104 that can interact with assembly holes 94 on the main body 90 , along with fasteners (not shown), to secure the main body 90 and laser scanner 60 together. It will be clear that a variety of screws and other fasteners can be used to attach the main body 90 and the laser scanner 60 . For example, in some embodiments they can be attached by a snap-lock mechanism, allowing easy attachment and removal. Further, in some embodiments a repeatable kinematic mount can be used, where the laser scanner 60 can be removed and remounted to the main body 90 without tools. It can be remounted with a high level of repeatability through the use of a 3-point kinematic seat as is known in the industry. [0056] When the PCMM 1 is intended to provide accurate position data, the PCMM can be designed to minimize the errors at both the contact sensitive member 55 and at the non-contact coordinate detection device 60 . The error of the coordinate acquisition member 50 can be reduced by minimizing the effect of the errors of the last three axes on both the contact sensitive member 55 and the non-contact coordinate detection device 60 . The maximum error of the contact sensitive member 55 can be represented in the following equations as Ep, which is primarily a function of the errors of each of the last three axes (L 1 -L 3 ) and the distances from the probe center to the axes. Likewise, the error of the non-contact coordinate detection device 60 can be represented as Es and is primarily a function of the errors of each of the last three axes (L 1 -L 3 ) and the distances from the optical center point P 1 to the axes. [0000] Ep =( d 1 *e 1)+( d 2 *e 2)+( d 3 *e 3) [0000] Es =( d 1′*e1)+( d 2 ′*e 2)+( d 3 ′*e 3) [0057] Where e 1 , e 2 , and e 3 represent the absolute value of the angular error at each of the three last axes of rotation at the articulation members 30 , 31 , and 32 respectively; and d 1 , d 2 , d 3 , d 1 ′, d 2 ′, and d 3 ′ represent the distance from the respective axes to either the probe center or the optical center point (or laser focus) P 1 . As will be explained in further detail to follow, the PCMM 1 can enhance the accuracy of the coordinate acquisition member 50 by supplying a superior geometry to reduce both errors Ep and Es while at the same time balancing the Center of Gravity (CG) of the coordinate acquisition member 50 over the handle 40 and reducing the overall height of the coordinate acquisition member 50 (d 4 ) as shown in FIG. 2D . [0058] When the laser scanner 60 mounts the main body 90 , a variety of geometric properties can arise between coordinate acquisition elements. For example, as depicted the camera 70 , the contact sensitive member 55 , and the laser 65 can be directly integrated with the last axis L 1 . For example, as depicted the camera 70 , contact sensitive member 55 , and laser 65 can be generally collinear when viewing from the front (e.g. along axis L 1 ), with the contact sensitive member 55 in the middle and aligned with the last axis L 1 (i.e. d 1 =0). Further, as depicted the upper housing 80 , contact sensitive member 55 , and the laser 65 can be arranged generally parallel to the last axis L 1 . However, the camera 70 can be oriented at an angle relative to the last axis L 1 so as to view the laser plane. [0059] Such arrangements can be advantageous in a number of ways. For example, in this arrangement the angular position of the elements about L 1 can be approximately equal (with the exception of a 180 degree offset when on different sides of the last axis L 1 ), simplifying data processing requirements. As another example, providing these elements aligned with the last axis L 1 can facilitate counterbalancing the weight of these elements about the last axis, reducing error from possible deflection and easing movement about the axis. As depicted in FIG. 2D , the center of gravity (CG) of the coordinate acquisition member 50 can lie along L 1 . Even further, the error associated with the angle of rotation about the last axis L 1 is amplified by the perpendicular distance from the axis to the center of the laser plane emitted by the laser 65 (depicted as d 1 in FIG. 2D ). In this orientation, the perpendicular distance is minimized. In some embodiments, the perpendicular distance from the center of the laser plane to the last axis can be no greater than 35 mm. Notably, in other embodiments it may be desirable to move the laser 65 even closer to the last axis L 1 , such as by aligning directly therewith. However, the accuracy of the contact sensitive member 55 is also partially dependent on its proximity to the last axis L 1 ; and, as described below, some other advantages can arise from separating the laser 65 from the camera 70 . [0060] As further depicted, when the laser scanner 60 mounts the main body 90 , the contact sensitive member 55 and the laser coordinate detection device 60 can form a compact design. For example, the laser 65 and/or the camera 70 can extend past the one or both of the bearings 150 , 151 . As depicted, the laser 65 extends, at least partially, beyond the bearings 151 but not the bearings 150 ; and the camera 70 extends beyond both bearings. In other embodiments, these elements can extend to the bearings, and not pass them. Generally, causing these elements to overlap reduces the necessary length of the coordinate acquisition member 50 . [0061] In some embodiments such compact designs can allow the coordinate acquisition elements to be closer to the second to last axis L 2 , as well as the last axis L 1 . Accordingly, the distance between the second to last axis L 2 and the points of measurement (e.g. at the tip of the contact sensitive member 55 and/or at the focus P 1 of the camera 70 ) can be reduced. As the error in the angular position of the coordinate acquisition member 50 along the second to last axis L 2 is amplified by these distances, this also reduces the error of the PCMM 1 in other ways. For example, the compact design can also reduce error related to the distance from the focus P 1 to the third to last axis L 3 , represented as d 3 ′. Additionally, providing the elements of the coordinate acquisition member 50 closer to the second and third to last axes L 2 , L 3 can reduce deflection, reducing error even further. In some embodiments the contact sensitive member 55 can be within 185 mm of the second and/or third to last axis L 2 , L 3 , and the focus P 1 of the camera 70 can be within 285 mm of the third to last axis. As best depicted in FIG. 2D , the compact design can further bring a center of gravity (CG) of the coordinate acquisition member 50 closer to a central axis L 5 of the handle 40 . In some embodiments, the distance between the center of gravity and the central axis of the handle 40 can be no greater than 20 mm. As yet another advantage to the compact design, the vertical height d 4 of the coordinate acquisition member 50 can be reduced, allowing measurement in tighter spots. In some embodiments the height can be no greater than 260 mm. Notably, as the coordinate acquisition member 50 in the depicted embodiment rotates about the last axis L 1 , the height d 4 can also represent a maximum length of the coordinate acquisition member 50 . [0062] In some embodiments, the laser scanner 60 can include additional advantages. For example, the laser scanner 60 can isolate the laser 65 from heat generated by the other parts of the PCMM arm 1 . For example, as depicted in FIG. 3 , a base plate 75 holds the laser 65 at one end and the camera 70 at the other, separated by the contact sensitive member 55 . In some embodiments the base plate 75 can include a material with a low coefficient of thermal expansion such as Invar, Ceramic, or Carbon Fiber. Reducing thermal expansion can reduce changes in the position and orientation of the laser 65 and/or the camera 70 , which could create problems such as introducing additional error into the measurements. Similarly, the base plate 75 can also include a material with a low thermal conductivity, hindering transmission of heat, for example, from the camera 70 to the laser 65 or PCMM 1 . [0063] As depicted, the camera 70 can be held in an upper housing 80 of the laser scanner 60 , and in some embodiments the upper housing can include multiple cameras. The upper housing 80 can include materials such as aluminum or plastic. Additionally, the upper housing 80 can protect the camera 70 from atmospheric contaminants such as dust, liquids, ambient light, etc. Similarly, the laser 65 can be protected by the recess 92 of the main body 90 . In some embodiments, the recess 92 can include a thermal isolation disc or plate with a low coefficient of thermal expansion and/or conductivity, protecting the laser from external heat and substantially preserving its alignment. [0064] In many embodiments, the electronics 160 associated with the laser coordinate detection device 60 can create a substantial amount of heat. As discussed above, various components can be protected from this heat with materials having low coefficients of thermal expansion and conductivity for example. As depicted, the electronics 160 can be positioned in the upper housing 80 of the laser scanner 60 . [0065] However, in other embodiments the electronics 160 can be positioned further from the sensors 55 , 60 , such as in a completely separate housing. For example, in some embodiments the electronics 160 can be held by the laser scanner 60 in a separate housing, also attached to the base plate 75 . In other embodiments, the electronics 160 can be located further down the PCMM 1 , such as in a rigid transfer member 20 or in the base 10 . Moving the electronics 160 further down the PCMM 1 can reduce weight at the end of the arm, minimizing deflection of the arm. Similarly, in some embodiments the electronics 160 can be completely outside the PCMM 1 , such as in a separate computer. Data from the sensors 55 , 70 can be transmitted through the PCMM 1 on an internal cable in the arm, wirelessly, or by other data transmission methods. In some embodiments, data ports 93 , 101 can include spring loaded pins such that no cables are externally exposed. [0066] As another advantage of the depicted embodiment, the depicted layout of the system can use a smaller volume. The laser coordinate detection device 60 can sometimes operate on a theory of triangulation. Accordingly, it may be desirable to leave some distance between the laser 65 and the camera 70 . The depicted embodiment advantageously places the contact sensitive member 55 within this space, reducing the volume of the coordinate acquisition member 50 . Additionally, the last axis L 1 also passes through this space, balancing the system and reducing the coordinate acquisition member's 50 rotational volume. In this configuration, the combination of axis and laser scanner can further be uniquely optimized to reduce weight, as the more compact design reduces deflection, and accordingly reduces the need for heavy-load bearing materials. [0067] To further illustrate the advantages of the above-described embodiments, FIGS. 4-7 depict modified configurations in which the laser scanner and or image sensor is positioned in different locations. In FIGS. 4A , 4 B, the scanner is centered on the last axis, displacing the contact sensitive member, and is further forward. Accordingly, d 1 ′ has been reduced to zero, but d 1 has increased, essentially transferring error from the non-contact measuring device to the contact measuring device. Additionally, in this embodiment, both the measuring devices 55 , 60 are further from the second and third to last axes L 2 , L 3 , increasing d 2 , d 2 ′, d 3 , and d 3 ′. Even further, as the center of gravity CG is displaced forward, away from the handle's axis L 5 , the coordinate acquisition member can be more difficult to maneuver as d 5 is larger, and can further suffer greater deflection. [0068] In FIGS. 5A , 5 B, the scanner is above the last axis. Accordingly, there is a large distance between the last axis and the laser area (d 1 ′) as well as a larger maximum length d 4 of the coordinate acquisition member 50 . Further, displacing the center of gravity CG from the last axis L 1 can hinder the maneuverability of the coordinate acquisition member 50 . Additionally, the scanner is slightly more forward, increasing the distance from the focus P 1 to the second and third to last axes (d 3 ′). [0069] In FIGS. 6A , 6 B, the scanner is further forward and below the last axis. Accordingly, there is a large distance between the last axis and the laser area (d 1 ′) and a similarly large distance between the second and third to last axes and the scanner's focus P 1 (d 3 ′). Further, the center of gravity CG is displaced from the last axis L 1 and the handle (d 5 ), hindering the maneuverability of the coordinate acquisition member 50 . [0070] In FIG. 7A , 7 B, 7 C, with the scanner off to the side of the last axis, there is a large distance between the last axis and the laser area (d 1 ′), and a large distance between the second and third to last axes and the scanner's focus P 1 (d 3 ′). Further, displacing the center of gravity CG from the last axis L 1 and the handle's axis L 5 can hinder the maneuverability of the coordinate acquisition member 50 . [0071] The various devices, methods, procedures, and techniques described above provide a number of ways to carry out the invention. Of course, it is to be understood that not necessarily all objectives or advantages described may be achieved in accordance with any particular embodiment described herein. Also, although the invention has been disclosed in the context of certain embodiments and examples, it will be understood by those skilled in the art that the invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses and obvious modifications and equivalents thereof. Accordingly, the invention is not intended to be limited by the specific disclosures of preferred embodiments herein.

4y

This application is a continuation-in-part of copending application Ser. No. 447,799, filed on Dec. 8, 1989 now abandoned. The United States government may own certain rights in this and the patent application. BACKGROUND OF THE DISCLOSURE The present disclosure is directed to isolated peptides useful in the testing of and diagnosis of infection by the human parasite of the genus Schistosoma and to methods of testing employing such peptides. The world distribution of schistosomiasis is typically endemic in tropical zones wherein the schistosome's life cycle is dependent on known, regionally specific intermediate snail hosts. See, Hunter's Tropical Medicine, Sixth Edition, W.D. Saunders Company, pages 713 et seq. The epidemiology of schistosomiasis typically involves geographic regions between 36° north and 34° south latitude and further characterized by having fresh water temperatures in the range of about 25°-30° C. The endemic populations include people of all ages, but the disease particularly seems to attack young boys, ages 5 to 10. The infection mechanism involves mere contact with the water of the region assuming the appropriate snail population. Other details regarding the pathology of the disease are set forth in representative sources such as the text mentioned above. Suffice it to say, it is a debilitating parasitic disease. Present day techniques of detection of the disease in the human host primarily involve identification of the schistosome egg. There are multiple techniques available, but they primarily involve microscopic examination of human feces, and such tests are set forth in the referenced text. Prior art serologic tests have tended to be somewhat insensitive and somewhat lacking in specificity. Most serologic tests that have been developed can provide positive indication of the disease only exceedingly late after the onset of infection. By contrast, the test of the present disclosure will detect the antibody before or prior to egg production by the parasite worm in the human host. As can be understood, the chronic symptoms of schistosome infestation are more severe than the subtle symptoms occurring prior to egg production. Thus, prior art test responses (sensitivity and specificity) are variable because impure schistosomal antigens are used. Contrary to this problem, the peptides of the present disclosure can be synthesized in substantial purity and consistency and, in that sense, represent the ultimate in available test reagents. Testing can now be carried out with a minimum of specialized laboratory equipment, even in ill-equipped field conditions in an endemic population. Thus, the peptides can be employed in testing large population groups or a single individual, and these tests can be carried out, even in the most adverse of circumstances. BRIEF DESCRIPTION OF THE DRAWINGS So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. FIGS. 1A, 1B, 2A, 2B, 3A and 3B are VARIED graphs which describe for comparative purposes the peptide test reagent set forth in the present disclosure. FIG. 1A shows hydrophilicity analysis of the S. mansoni cysteine proteinase, CP1. The three probable antigenic sites (I, II, and III) are indicated by the solid bars. FIG. 1B shows, the primary sequence of each site is indicated by open boxes. Synthetic peptide sequences SMP 22 and SMP 11 are shown by hatched boxes in FIG. 1B. FIGS. 2A and 2B show antibody response (IgG) in the sera of uninfected (light stipple) or S. mansoni - infected (dark stipple) mice (FIG. 2A) and humans (FIG. 2B) to CP1 derived synthetic peptides. Equimolar concentrations of peptides were covalently linked to microtiter wells. Each value is the mean of at least 3 separate wells. Each value is the mean of at least 3 separate determinations; standard deviations are indicated by error bars. Statistical comparisons were evaluated by student's t test (unpaired). FIGS. 3A and 3B show the results of a competition ELISA assay using intact CP1 bound to microtiter wells. S. mansoni - infected mouse (FIG. 3A) or human (FIG. 3B) sera (solid line) were pre-incubated overnight at 4C. with SMP 22 (dotted, dashed line) or SMP 12 (dotted line). Control sera are indicated (dashed line). Each value is the mean of three separate experiments; standard deviation for each dilution is indicated by error bars. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The schistosoma parasite proteinase CP1 has been previously isolated, purified and characterized. See Davis, A.H., et al. Cloning and Gene Expression of Schistosoma Mansoni Proteinase. J. Biol. Chem. 262:12851-855 (1987). This protein, characterized further as a 1-Galactosidase fusion protein, has been determined to provide a strongly specific and sensitive immune response indicative of the presence of schistosomiasis infection, whether that infection be by S. mansoni or either of the other two schistosoma species known to cause this disease, namely S. japonicum and S. haematobium. As a generalization, laboratory animals (preferably mice) can be infected with the schistosome parasite which results in an acute infection typically after about two months of maturation. The parasites are collected from the mice and the CP1 protein is ultimately isolated from the worms. This represents about one part in one thousand of the total protein captured. The native protein can be used as a test reagent, but that is usually difficult to accomplish, primarily because of two reasons. For one, it is a fairly large protein. Moreover, it is a protein which is difficult to isolate and provide in a relatively pure state. By contrast, it is possible to clone the CP1 protein. Its description is set forth by Alan Davis as noted above. Through this, the recombinant product can be provided. The Schistosoma mansoni cysteine proteinase CP1 has been subjected to hydrophilic analysis. FIG. 1A attached hereto sets forth this analysis where the abscissa is the residue number and the ordinate indicates relative site activity. As shown in FIG. 1A, three sites are suggested, and it will be observed that Sites I and II are quite similar. Two synthetic peptides, SMP 11 and SMP 22, shown in FIG. 1B can be synthesized using the data in FIG. 1A where the Sites I, II and II are represented by boxes in both FIGS. 1A and 1B; It will be noted in particular that the larger of the peptides involves the full range of the residue numbers from 89 to 111, a range of 23; the smaller of the synthetic peptides involves twelve, and both appear to have the antibody binding propensity verified by test procedures. Inspection of FIG. 1A will show that the hydrophilic analysis of the protein CP1 over the full length sequence of that proteinase clone supports the three sites designated in FIG. 1A. The primary sequence at the sites carries a strong suggestion that these areas involve repeat epitopes. The peptides involving Sites I and II or Site II only are thus designated as SMP 22, and SMP 11 respectively. Synthesis of these and testing for antibody binding activity has verified the test reagent success. Analysis of the CP1 protein primary sequence has determined three peak hydrophilic areas which are identified in FIG. 1A as Sites I, II and III. Synthetic peptides encompassing Sites I and II (jointly) or Site II alone have shown an ability to bind antibodies specific to schistosomiasis infection. Moreover, they complete with the binding of polycolonal antibodies to the whole protein CP1. Applicants have determined that synthetic peptides containing the sequence Lys Val Leu Lys Ser Gly Lys Asn Asp (SEQ ID NO: 1) comprise an immunodominant epitope of the protein molecule CP1. Test verification using an ELISA assay system has distinguished sera from schistosome infected humans, and a contrast from those not infected has been confirmed. In other words, a schistosome infected human has a distinctive antibody which responds to the test while those who are not infected do not so respond. One such test which verifies the success of both peptides SMP 11 and SMP 22 shows a covalent linking mechanism to humans (or mice for that matter). In this test, a control peptide formed of a randomly scrambled version of SMP 11, was also employed and the results compared to those obtained with the SMP 11 and SMP 22. In all instances, sera from infected mice and humans provided significantly higher absorbance in contrast with the controlled sera. FIGS. 2A and 2B of the drawings illustrates this contrast with human and mouse response to the three peptides. As will be observed, FIGS. 2A and 2B show the sera of uninfected mice or humans in contrast with Schistosoma mansoni infected mice and humans. In all tests, the peptide was tested with equimolar concentrations of peptides which are covalently linked to microtiter wells. Multiple tests were used to provide the data of FIGS. 2A and 2B, and the standard deviations are indicated by the error bars imposed thereon. FIG. 2 shows that sera from infected mice produced greater binding by both SMP 11 and SMP 22. It appears further that SMP 22 can bind significantly more antibody than SMP 11. Results from infected human sera are similar. However, the scrambled peptide bound the antibody to the same degree as did other unrelated peptides which may indicate polyclonal activation of the plasma cells. FIGS. 3A and 3B show dilution curves for antibody binding of controlled sera, infected sera only, and infected sera pre-incubated with peptides. The dilution should be noted first; the first dilution is typically in the ratio of 1:20. Subsequent dilutions by two are implemented to have ratios of 1:40, 1:80, 1:160, etc. as shown in the abscissa of FIGS. 3A and 3B. A green light (wave length of 410 nanometers) is used for the absorbence test. In the mouse, both peptides (SMP 11 and also SMP 22) were effective inhibitors of antibody binding to the intact CP1 protein molecule even at quite high serum concentrations. SMP 22 showed slightly more inhibitory activity compared with the SMP 11 peptide. Both peptides completely inhibited binding at a serum dilution of 1:80, see FIG. 3A. By contrast, antibodies from human infection were partially inhibited at higher serum concentrations and did not reach complete inhibitions until sera was diluted to about 1:640. This data suggests that SMP 22 inhibited better than SMP 11. The conclusion derived from the foregoing data is that the single epitope (SMP 11) is capable of inhibiting polyclonal antibody binding to the protein CP1. This may indicate the existence of a single epitope, or likely also suggests two or three cross-reactive epitopes. The differences in the degree of inhibition between mice and humans probably derive from the differences in the infection, namely, that the mice are acutely infected while the human sera is from those who are only chronically infected. Detection of protein CP1 immune complex in human sera, coupled with high titer verification, enables a number of desirable testing procedures. The microtiter process involves the addition of a second antibody and subsequent absorbance testing at a specified light frequency, and yields a measure of light transmission. This in turn yields both a qualitative and quantitative result; that is, the subject's blood is either infected or not, and a relative measure of infection is indicated in accordance with known techniques involving microtiter testing. However, while the microtiter test procedure is well known and can be carried out in a well equipped laboratory, it is not always available. In remote endemic populations, as an alternative to the microtiter testing procedure set forth above, advantage can be taken of the ELISA or LATEX AGGLUTINATION assays. In these procedures, the isolated peptide (either SMP 11 or SMP 22 or both) can be linked to an inert substrate and it will subsequently bind to antibodies from patient blood. In a typical agglutination assay, polystyrene beads which are a few microns in diameter, commonly more than ten microns in diameter up to perhaps one hundred or two hundred microns in diameter, are coated with the isolated peptide of the present disclosure by means of a suitable solvent removed by evaporation and then distributed evenly on the test surface. This yields an exposed set of polystyrene beads of appropriate size having receptor sites defined by the peptide coating. When the infected patient's blood serum is applied to this test surface, there will be an aggregation (i.e., clumping) of the beads. Suitable test devices employing the latex agglutination assay process may be devised from paper or cardboard in the form of a slide coated with polystyrene beads supported on a carrier which is typically a black glossy waxed paper. Where there are no antibodies, i.e., when the patient is not infected, the clumping does not occur. Clumping occurs by the linking of the antibody from the patient's serum. This can be visually recognized and is a test which can be carried out to provide simple, straightforward and quickly determined infection measurement. This test utilizing the supportive substrate described above with the carrier beads (subject to agglutination on positive testing) is therefore the kind of test procedure which can be carried out in remote conditions absent electrical power for operation of test equipment, and does not require highly trained test personnel to execute the test reliably. In other words, a low cost, inexpensive field use test is provided thereby. The test procedure of this invention is specific and particularly suitable for the Schistosoma mansoni species, but will also be specific for and is therefore highly useful with the two other schistosome species that commonly infect humans. It is not cross-reactive to other blood serum antibodies that are typically encountered in the endemic populations (malaria being one example) or to infections from other closely related trematodes, such as F. hepatica or C. sinensis. Through the use of the present test, a positive and specific indication for the schistosomiasis infection is thus provided so that treatment can proceed promptly thereafter. __________________________________________________________________________SEQUENCE LISTING(1) GENERAL INFORMATION:(iii) NUMBER OF SEQUENCES: 3(2) INFORMATION FOR SEQ ID NO:1:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 9 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:LysValLeuLysSe rGlyLysAsnAsp15(2) INFORMATION FOR SEQ ID NO:2:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 24 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(v) FRAGMENT TYPE: internal fragment(x) PUBLICATION INFORMATION:(A) AUTHORS: Davis, A.H.(B) TITLE: Cloning and Gene Expression of SchistosomaMansoni Proteinase(C) JOURNAL: J. Biol. Chem.(D) VOLUME: 262(F) PAGES: 12851-855(G) DATE: 1987(K) RELEVANT RESIDUES IN SEQ ID NO:2: FROM 89 TO 112(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:ThrPheLeuLysValLeuLysGlyAspLysSerAla9 095100GlyGlyLysValLeuLysSerGlyLysAsnAspAsp105110(2) INFORMATION FOR SEQ ID NO:3:(i) SEQUENCE CHARACTERISTICS:(A) LENGTH: 12 amino acids(B) TYPE: amino acid(D) TOPOLOGY: linear(ii) MOLECULE TYPE: peptide(v) FRAGMENT TYPE: c-terminal fragment(x) PUBLICATION INFORMATION:(A) AUTHORS: Davis, A.H.(B) TITLE: Cloning and Gene Expression of SchistosomaMansoni Proteinase(C) JOURNAL: J. Biol. Chem.(D) VOLUME: 262(F) PAGES: 12851-855(G) DATE: 1987 (K) RELEVANT RESIDUES IN SEQ ID NO:2: FROM 89TO 112(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:AspGlnGlnTyrLysGluValLysArgGluThrAsp230235240

4y

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to power feed path switching circuits, and more particularly to a power feed path switching circuit which is provided in a branching unit for branching communications paths in a communications system. An optical underwater communications system uses an underwater branching unit for branching an optical fiber cable in order to connect a plurality of points (stations). Normally, such an underwater branching unit has the function of switching power feed paths in order to prevent communications from being broken due to a fault in a power feed path. Recently, the number of underwater branching units used in a single communications system has been on the increasing trend. Hence, it is desired to provide a power feed path switching circuit capable of switching power feed paths with ease. FIGS. 1A and 1B are block diagrams illustrating conventional power feed switching. Referring to FIG. 1A, a branching unit (BU) 10 connects a cable extending from a station A and a cable extending from a station B in series. A repeater (not shown in FIG. 1A), which is provided in the cables, is supplied with power from both the stations A and B in the two directions. The above power feed is called two-end power feed. If a fault has occurred in one of the two stations A and B, the repeater can be supplied with power from the other station. Hence, the two-end power feed shown in FIG. 1A has high reliability. A cable extending from a station C is ground to the sea SE (sea earth) in the branching unit 10. A repeater provided in the cable extending from the station C is supplied with power from only the station C. This power feed is called single-end power feed. If a fault has occurred in the cable connecting the branching unit 10 and the station B, the cable extending from the station B is grounded to the sea in the branching unit 10, as shown in FIG. 1B. Further, the branching unit 10 connects the station A to the station C in series. FIG. 2 shows a conventional power feed path switching circuit provided in the branching unit 10 shown in FIGS. A and 1B. An end 21 of the cable connected to he station A is connected to an end of a relay coil RL2 via a relay switch rl3. Similarly, ends 22 and 23 of the cables connected to the stations B and C are connected to ends of relay coils RL1 and RL3 via relay switches rl2 and rl1, respectively. The other ends of the relay coils RL1, RL2, and RL3 are connected to each other at a branching node X. When there are no currents flowing in the relay coils RL1, RL2 and RL3, the relay switches rl1, rl2 and rl3 connect respective terminals a and b. When predetermined amounts of currents flow in the relay coils RL1, RL2 and RL3, the relay switches rl1, rl2 and rl3 connect terminals a and c, and the cable ends 23, 22 and 21 are grounded to the sea (SE), respectively. In order to perform the two-end power feed between the stations A and B and perform the single-end power feed between the station C and the sea ground SE, a constant current I is made to flow in the relay coil RL1 from the station B, and a constant voltage is applied to the cable at the station A. In this case, the constant current I has a large amount enough to drive the relay switch rl1, and the constant voltage has a value which causes the potential of the node X to be set equal to the ground level. In response to the constant current flowing in the relay coil RL1, the relay switch rl1 connects the terminals a and c. Since the potential of the node X is equal to the ground level when the switch rl1 operates, a hot switching phenomenon can be prevented in which a charge stored in the cable between the station C and the branching unit 10 flows to the sea ground via the terminals a and c. If such a charge flows, the terminals a and c may be damaged. Recently, there has been an increasing trend to use a large number of underwater branching units used in a single communications system. FIG. 3 shows a communications system having n branching units (BU) 31 1 -31 n where n is an integer. The n branching units 31 1 -30 n are cascaded, and terminal stations 30 0 -30 n+1 are connected to these branching units, as shown in FIG. 3. A description will now be given of power feed between the terminal stations 30 0 -30 n+1 . It will now be assumed that currents necessary to switch the relay switches rl1 of the branching units 31 1 -31 n are denoted by I 1 -I n in which I 1 <I 2 <. . . <I n . FIGS. 4A, 4B and 4C illustrate a procedure for performing a switching operation on the branching units 31 1 -31 n . Referring to FIG. 4A, a constant voltage V 1 is applied to the cable at the station 30 0 , and a constant current I 1 is made to flow in the cable from the station 30 n+1 in order to drive the switch rl1 in the branching unit 31 1 in a state in which the node X in the branching unit 31 1 is maintained at the ground level. Thereby, the switch rl1 in the branching unit 31 1 selects the sea ground SE. Next, in order to make the switch rl1 in the branching unit 31 2 select the sea ground in a state where the node X in the branching unit 31 2 is maintained at the ground level, as shown in FIG. 4B, a constant voltage V 2 is applied to the cable at the station 30 0 , and a constant current I 2 is made to flow in the cable from the station 30 n+1 . Then, as shown in FIG. 4C, a constant voltage V 3 is applied to the cable at the station 30 0 , and a constant current I 3 is made to flow in the cable from the station 30 n+1 in order to drive the switch rl1 in the branching unit 31 3 in a state in which the node X in the branching unit 31 3 is maintained at the ground level. Thereby, the switch rl1 in the branching unit 31 3 selects the sea ground SE. In the same manner as described above, the other switches rl1 are sequentially driven to select the sea ground. In order to drive the switches rl1 in the branching units so that the terminals a and b are connected to each other, the nodes X in the branching units 31 n -31 1 are sequentially set to the ground level in this order. As described above, it is necessary to sequentially set the nodes X in the branching units 31 1 -31 n to the ground level in order to drive the relays rl1 provided therein. Hence, it is necessary for the currents I 1 -I n to have different quantities in order to drive only one of the relays rl1 at one time. In practice, it is required that the differences among the quantities of the currents I 1 -I n be large enough to cope with deterioration in the relay coils with age or the like. Further, it is troublesome to sequentially set the nodes X in the branching units 31 1 -31 n one by one. Furthermore, the above-mentioned conventional power feed path switching circuit has the following disadvantage. Referring to FIG. 5, a fault has occurred and the branching unit 31 3 is grounded. In this case, the overall branching unit 31 3 is fixed at the ground level. The current I 1 is needed to drive the relay switch rl1 in the branching unit 31 1 . However, the branching unit 31 3 is fixed at the ground level, and hence the node X in the branching unit 31 1 is at a potential a with the voltage V 1 applied to the cable at the station 30 0 . In this case, the hot-switching phenomenon takes place, and the relay switch rl1 in the branching unit 31 1 may be damaged. Similarly, the current I 2 is needed to drive the relay switch rl1 in the branching unit 31 2 . However, the node X in the branching unit 31 2 is at a potential b with the voltage V 2 applied to the cable at the station 30 0 . Hence, the hot-switching phenomenon takes place, and the relay switch rl1 in the branching unit 31 2 may be damaged. A similar problem arising from the fault in the branching unit 31 3 will occur in the branching units. SUMMARY OF THE INVENTION It is a general object of the present invention to provide a power feed path switching circuit in which the above disadvantages are eliminated. A more specific object of the present invention is to provide a power feed path switching circuit which needs a small number of currents necessary for switching in branching units and a simple switching procedure and which can perform switching without the hot-switching phenomenon even when a fault has occurred in a communications system in which the power feed path switching circuit is provided. The above objects of the present invention are achieved by a power feed path switching circuit via which first, second and third stations are coupled to each other in a normal state, the power feed path switching circuit comprising: first means for sensing a first current flowing in a first path connecting the first and second stations via a branching node and for disconnecting a second path connecting the third station and the branching node from the branching node when the first current is sensed; second means for sensing a second current flowing in the first path and for gradually discharging the second path when the second current is sensed: and third means for sensing a third current flowing in the first path and for grounding the second path when the third current is sensed. The above objects of the present invention are achieved by a power feed path switching circuit via which first, second and third stations are coupled to each other in a normal state, the power feed path switching circuit comprising: first means for sensing a predetermined current flowing in a first path connecting the first and second stations via a branching node and for disconnecting a second path connecting the third station and the branching node from the branching node when the predetermined current is sensed; second means, coupled to the first means, for gradually discharging the second path when a first predetermined period has elapsed after the predetermined current is sensed; and third means, coupled to the first means, for grounding the second path when a second predetermined period longer than the first predetermined period has elapsed after the predetermined current is sensed. The above-mentioned objects of the present invention are also achieved by a power feed path switching circuit via which first, second and third stations are coupled to each other in a normal state, the power feed path switching circuit comprising: first means for sensing first currents flowing in paths respectively connecting two of the first, second and third stations via a branching node and for disconnecting, when one of the first currents flowing between two of the first, second and third stations is sensed, one of the paths connected to a remaining one of the first, second and third stations from the branching node; second means for sensing a second current flowing between the two of the first, second and third stations and for gradually discharging the one of the paths connected to the remaining one of the first, second and third stations when the second current is sensed; and third means for sensing a third current flowing between the two of the first, second and third stations for grounding the above-mentioned one of the paths connected to the remaining one of the first, second and third stations when the third current is sensed. The above-mentioned objects of the present invention are also achieved by a power feed path switching circuit via which first, second and third stations are coupled to each other in a normal state, the power feed path switching circuit comprising: first means for sensing predetermined currents flowing in paths connecting two of the first, second and third stations via a branching node and for disconnecting, when one of the predetermined currents flowing between two of the first, second and third stations is sensed, one of the paths connected to a remaining one of the first, second and third stations from the branching node; second means, coupled to the first means, for gradually discharging the above-mentioned one of the paths connected to the remaining one of the first, second and third stations when a first predetermined period has elapsed after the predetermined current is sensed; and third means, coupled to the first means, for grounding the above-mentioned one of the paths connected to the remaining one of the first, second and third stations when a second predetermined period longer than the first predetermined period has elapsed after the predetermined current is sensed. BRIEF DESCRIPTION OF THE DRAWINGS Other objects, features and advantages of the present invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings, in which: FIGS. 1A and 1B illustrate a conventional power feed path switching operation: FIG. 2 is a circuit diagram of a conventional power feed path switching circuit provided in a branching unit in a communications system; FIG. 3 is a block diagram of a communications systems in which a plurality of branching units are provided; FIGS. 4A, 4B and 4C are diagrams illustrating a conventional switching procedure in the communications system; FIG. 5 is a diagram illustrating disadvantages in the conventional switching procedure; FIG. 6 is a circuit diagram of a power feed path switching circuit according to a first embodiment of the present invention; FIG. 7 is a circuit diagram of a power feed path switching circuit according to a second embodiment of the present invention; FIG. 8 is a circuit diagram of a variation of the circuit configuration shown in FIG. 6; FIG. 9 is a block diagram of a power feed system to which the circuit configuration shown in FIG. 8 is applied; FIG. 10 is a circuit diagram of a variation of the circuit configuration shown in FIG. 7; FIG. 11 is a block diagram of a power feed system to which the circuit configuration shown in FIG. 8 is applied; and FIG. 12 is a block diagram of a power feed path switching system according to a third embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 6 illustrates a power feed path switching circuit 40 according to a first embodiment of the present invention. The power feed path switching circuit 40 shown in FIG. 6 is provided in a branching unit. First, second and third relay coils RL11, RL12 and RL13 are connected in series between cable ends 41 and 42 coupled to the stations A and B, respectively. Normally, a first relay coil RL11 connects the cable end 41 to cable ends 42 and 43. The cable end 43 is connected to the station C. The first relay switch rl11 is opened so that the cable end 43 is disconnected from circuits connected between the cable ends 41 and 42 when a first driving current flows in the first relay coil RL11. Strictly speaking, a current equal to or greater than the first driving current flows in the first relay coil RL11, the first relay switch rl11 is opened. The above holds true for other currents described in the specification. A second relay switch rl12 is provided between the cable end 43 and a resistor Rl. Normally, the second relay switch rl12 is maintained in the open state. When a second driving current greater than the first driving current flows in the relay coil RL12, the second relay switch rl12 is closed so that the cable end 43 is grounded via the resistor Rl. In this state, a charge stored in the cable having the cable end 43 is allowed to flow to the sea ground via the resistor Rl, so that the cable is gradually discharged. A third relay switch rl13 is connected across the resistor Rl, and is normally maintained in the open state. When a third driving current greater than the second driving current flows in the third relay coil RL13, the third relay switch rl13 is closed so that the cable end 43 is directly grounded. That is, after the discharging of the cable having the cable end 43 is substantially completed, the cable end 43 is grounded. Hence, the switching between the power feed paths can be performed by increasing the current flowing in the cable between the cable ends 41 and 42 over only three steps, rather than setting the branching unit having the circuit 40 to the ground potential. FIG. 7 illustrates a power feed path switching circuit 60 according to a second embodiment of the present invention. The circuit 60 shown in FIG. 7 is provided in a branching unit. The relay coil RL11 7 is connected between the cable ends 41 and 42. The relay switch rl11 associated with the relay coil RL11 is connected between the cable ends 42 and 43. Normally, the relay switch rl11 is maintained in the closed state. When a predetermined driving current flows in the relay coil RL11, the relay switch rl11 is opened and hence the cable end 43 is disconnected from circuits provided between the cable ends 41 and 42. A power supply circuit 15, which is connected to the cable between the cable ends 41 and 42, starts power supply on the basis of the current flowing in the cable between the cable ends 41 and 42. A first switch circuit 12 is provided between the cable end 43 and the resistor Rl, and is normally maintained in the open state. The first switch circuit 12 is closed so that the cable end 43 is connected to the resistor Rl when a first period t 1 has elapsed after the power supply circuit 15 starts to supply power. Thereby, the cable terminal 43 is grounded via the resistor, and the cable extending from the cable end is gradually discharged via the resistor Rl. A second switch circuit 13 is connected across the resistor Rl, and is normally maintained in the open state. The second switch circuit 13 is closed so that the cable end 43 is directly grounded when a second period t 2 longer than the first period t 1 has elapsed after the power supply circuit 15 starts the power supply. Hence, the cable end 43 is grounded after the discharging of the cable is substantially completed. The switching process of the second embodiment of the present invention is simpler than that of the first embodiment thereof because the switching between the power feed paths can be performed by only driving the relay coil RL11. FIG. 8 is a circuit diagram of a variation 40A of the first embodiment of the present invention shown in FIG. 6. In FIG. 8, those parts that are the same as parts shown in FIG. 6 are given the same reference numbers. The variation shown in FIG. 8 includes a fourth relay coil RL14 and two relay switches rl14 1 and rl14 2 associated with the fourth relay coil RL14. The cable end 41 connected to the station A is coupled to the cable end 42 connected to the station B via the relay coils RL11, RL12 and RL13 connected in series. The cable end 42 is also coupled to the cable end 43 connected to the station C via the relay switches rl14 2 and rl11 connected in series. The cable end 43 is connected to one end of the relay switch rl14 1 and one end of the relay switch rl12. The other end of the relay switch rl14 1 is grounded via the relay coil RL14 via the resistor Rl having a large resistance enough to gradually discharge the cable having the cable end 43. The other end of the relay switch rl14 1 is also connected to one end of the relay switch rl13. The other end of the relay switch rl13 is connected to the other end of the relay switch rl14 1 . The relay switches rl11-rl13 are driven when the first, second and third driving currents I 1 , I 2 and I 3 (I 1 <I 2 <I 3 ) flow in the relay coils RL11, RL12 and RL13, respectively (strictly speaking, when currents greater than the first, second and third currents I 1 , I 2 and I 3 flow in the delay coils RL11, RL12 and RL13). The relay switches rl14 1 and rl14 2 are driven when a current equal to or greater than a predetermined current I flows in the relay coil RL14. A description will now be given, with reference to FIG. 8, of a case where the two-end power feed is performed between the stations A and B and the single-end power feed is performed between the station and the ground. The first step of a procedure for realizing the above power feed is to set the cable end 43 to the open state at the station C. The second step is to increase the current flowing in the cable between the stations A and B to the first driving current I 1 and to thereby close the associated relay switch rl11. The third step is to increase the current flowing in the cable between the stations A and B to the second driving current I 2 and to close the associated relay switch rl12. Hence, a charge stored in the cable provided between the station and the branching unit equipped with the power feed path switching circuit 40A is allowed to gradually flow to the ground via the resistor Rl. The fourth step is to increase the current flowing in the cable between the stations A and B to the third driving current I 3 and to close the associated switch rl13. Hence, the cable end 43 is grounded and the power feed path between the station C and the sea ground SE is established without the hot-switching phenomenon. The fifth step is to gradually start power feed from the station C. When the current flowing in the relay coil RL14 becomes equal to or greater than the predetermined driving current I, the associated relay switch rl14 1 is closed and held by itself. Further, the relay switch rl114 2 is opened and the cable end 43 is disconnected from circuits in the cable between the stations A and B. Even if the relay switch rl11 returns to the original state (closed state) due to a fault of power feed between the stations A and B, the power feed between the station C and the ground is not affected at all. Further, it is not necessary to set the branching unit equipped with the power feed path switching circuit to the ground potential at the time of switching the power feed paths. Furthermore, the switching of the power feed paths can be simultaneously performed at a plurality of branching units. The driving currents I 1 , I 2 and I 3 , which are different from each other, can be commonly used in the branching units. The predetermined driving current I flowing in the relay RL14 can have a quantity equal to one of the driving currents I 1 , I 2 and I 3 or an arbitrary quantity different from the quantities of these driving currents. FIG. 9 illustrates a power feed system to which the first embodiment of the present invention is applied. The power feed system shown in FIG. 9 includes n cascaded branching units 40 1 -40 n which are the same as each other. Stations B-M are connected to the branching unit 40 1 -40 n , respectively. The station A is connected to the branching unit 40 1 , and a station N is connected to the branching unit 40 n . The power feed path switching units provided in the branching units 40 1 -40 n are the same as each other, and the same structural elements as those in the units are given the same reference numbers. Symbols including arrows having upward heads denote power sources provided in the stations A-N. The switching can be performed by only increasing the current flowing in the cable between the stations A and N in the order of I 1 <I 2 <I 3 , so that the stations B-M can be simultaneously switched to the single-end power feed in which the stations B-M are respectively grounded at the branching units 40 1 -40 n without the hot-switching phenomenon. Even if a fault, such as a grounding fault, has occurred in a cable connected to any of the stations A-N, the stations B-M can be simultaneously switched to the single-end power feed without the hot-switching phenomenon because there is no need to sequentially set the branching units to the ground potential. FIG. 10 illustrates a variation 60A of the second embodiment of the present invention shown in FIG. 7. In FIG. 10, parts that are the same as those shown in FIG. 7 are given the same reference numbers. The variation 60A shown in FIG. 10, has the relay switches rl14 1 and rl14 2 which are the same as those shown in FIG. 8. A description will now be given, with reference to FIG. 10, of a case where the two-end power feed is performed between the stations A and B and the single-end power feed is performed between the station C and the sea ground SE. The first step of a procedure for realizing the above power feed is to set the cable end 43 to the open state at the station C. The second step is to increase the current flowing in the cable between the stations A and B to the predetermined driving current and to thereby open the associated relay switch rl11. Hence, the cable end 43 is disconnected from circuits provided between the cable ends 41 and 42. The power supply circuit 15 branches the current flowing in the cable between the stations A and B. When a branched current i exceeds a threshold level, the power supply circuit 15 generates a voltage +V with respect to the ground E of the branching unit equipped with the present power feed path switching circuit. The switch circuit 12 is driven by the voltage +V generated by the power supply circuit 15, and charging of a capacitor C1 via one of two resistors R is started. The two resistors R are connected in series, and a connection nodes of these resistors is connected to the base of a transistor Q1. When the first period t 1 has elapsed after the charging is started, the transistor Q1 is turned ON and causes a driving current to flow in a relay coil RL12 connected between the collector of the transistor Q1 and the power supply circuit 15. Hence, the relay switch rl12 associated with the relay coil RL12 is closed. Then, a charge stored in the cable between the station C and the branching unit 60A is allowed to flow to the ground via the resistor Rl, so that the cable is gradually discharged. The voltage +V is also applied to the second switch circuit 13, and charging of a capacitor C2 via one of two resistors R is started. These two resistors R are connected in series and a connection node of these resistors is connected to the base of a transistor Q2. The capacitor C2 has a capacitance greater than that of the capacitor C1. When the second period t 2 longer than the first period t 1 has elapsed after the charging is started, the transistor Q2 is turned ON and causes a driving current to flow in a relay coil RL13 connected between the collector of the transistor Q2 and the power supply circuit 15. Hence, the relay switch rl13 associated with the relay coil RL13 is closed. As a result, the cable end 43 is grounded after the discharging of the cable extending from the station C is substantially completed. Thereafter, the power supply from the station C is gradually started. When the current flowing in the relay coil RL14 becomes equal to or greater than the predetermined driving current I, the associated relay switch rl14 1 is closed and held by itself. Further, the relay switch rl14 2 is opened and the cable end 43 is disconnected from circuits in the cable between the stations A and B. FIG. 11 is a block diagram of a power feed system to which the variation of the second embodiment shown in FIG. 10 is applied. The power feed system shown in FIG. 11 includes n cascaded branching units 60 1 -60 n which are the same as each other. Stations B-M are connected to the branching unit 60 1 -60 n , respectively. The station A is connected to the branching unit 60 1 , and a station N is connected to the branching unit 60 n . The power feed path switching units provided in the branching units 60 1 -60 n are the same as each other, and the same structural elements as those in the units are given the same reference numbers. Symbols including arrows having upward heads denote power sources provided in the stations A-N. The switching can be performed by only causing the predetermined driving current to flowing in the cable between the stations A and N. Hence the stations B-M can be simultaneously switched to the single-end power feed in which the stations B-M are respectively grounded at the branching units 60 1 -60 n without the hot-switching phenomenon. Even if a fault, such as a grounding fault, has occurred in a cable connected to any of the stations A-N, the stations B-M can be simultaneously switched to the single-end power feed without the hot-switching phenomenon because there is no need to sequentially set the branching units to the ground potential. FIG. 12 is a block diagram of a power feed path switching circuit 70 according to a third embodiment of the present invention. In FIG. 12, parts that are the same as parts shown in the previously described figures are given the same reference numbers. The power feed path switching circuit 70 includes circuit parts respectively provided for the cable ends 41, 42 and 43, each of the circuit parts corresponding to, for example, the circuit shown in FIG. 10. The station C is set to the open state, and a predetermined driving current Ia is made to flow from the station B to the station A. A voltage having polarities shown in FIG. 12 develops across a Zener diode ZDa. The voltage developing across the Zener diode ZDa flows a predetermined driving current in a relay coil RL11a, and an associated relay switch rl11a is opened. Further, the above voltage drives a power supply circuit (PU) 15a. When the first period t 1 has elapsed after the power supply circuit 15a is driven, a switch circuit 12a is closed and the cable extending from the station C is gradually discharged via a resistor Rla. When the second period t 2 longer than the first period t 1 has elapsed after the power supply circuit 15a is driven, a second switch circuit 13a is driven, and the cable end 43 is grounded via a relay coil RL14a. Thereafter, power feed from the station is started. When a predetermined driving current flows in the relay coil RL14a, an associated relay switch rl14 1a is closed and an associated relay switch rl14 2a is opened. Thereby, the current from the station C holds the single-end power feed by itself. The station A is opened to the open state, and a predetermined driving current Ib is made to flow from the station C to the station A. A voltage having polarities shown in FIG. 12 develops across a Zener diode ZDb. The voltage developing across the Zener diode ZDb flows a predetermined driving current in a relay coil RL11b, and an associated relay switch rl11b is opened. Further, the above voltage drives a power supply circuit (PU) 15b. When the first period t 1 has elapsed after the power supply circuit 15b is driven, a switch circuit 12b is closed and the cable extending from the station A is gradually discharged via a resistor Rlb. When the second period t 2 longer than the first period t 1 has elapsed after the power supply circuit 15b is driven, a second switch circuit 13b is driven, and the cable end 41 is grounded via a relay coil 14b. Thereafter, power feed from the station is started. When a predetermined driving current flows in the relay coil RL14b, an associated relay switch rl14 1b is closed and an associated relay switch rl14 2b is opened. Thereby, the current from the station A holds the single-end power feed by itself. The station B is opened to the open state, and a predetermined driving current Ic is made to flow from the station A to the station C. A voltage having polarities shown in FIG. 12 develops across a Zener diode ZDc. The voltage developing across the Zener diode ZDc flows a predetermined driving current in a relay coil RL11c, and an associated relay switch rl11c is opened. Further, the above voltage drives a power supply circuit (PU) 15c. When the first period t 1 has elapsed after the power supply circuit 15c is driven, a switch circuit 12c is closed and the cable extending from the station B is gradually discharged via a resistor Rlc. When the second period t 2 longer than the first period t 1 has elapsed after the power supply circuit 15c is driven, a second switch circuit 13c is driven, and the cable end 42 is grounded via a relay coil 14c. Thereafter, power feed from the station is started. When a predetermined driving current flows in the relay coil RL14c, an associated relay switch rl14 1c is closed and an associated relay switch rl14 2c is opened. Thereby, the current from the station B holds the single-end power feed by itself. With the structure shown in FIG. 12, it becomes possible to disconnect one of the stations A, B and C connected to the cable in which a fault has occurred and to maintain the two-end power feed between the other stations. It is also possible to use the circuits shown in FIGS. 6 through 8 instead of the circuits shown in FIG. 12. It is possible to replace the relay coils RL and relay switches rl by semiconductor switches or the like. It is also possible to define the first and second times t 1 and t 2 by means of circuits other than the circuits shown in FIG. 10. The present invention is not limited to the specifically disclosed embodiments, and variations and modifications may be made without departing from the scope of the present invention.

4y

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to filled articles such as comforters, pillows, duvets, quilts, sleeping bags and the like which are filled with low denier per filament fibers having a curvilinear structure. [0003] 2. Description of Related Art [0004] Down is widely accepted as the premium filling material for high-end insulated bedding. Its luxurious feel, refluffability and exceptional warmth and softness make it the standard in the industry. Polyester batting has been made in an attempt to emulate this feel, but even the best fibers fall short in terms of tactile feel, since down is a loose fill, and fiber batts are by definition structured. [0005] Attempts to create a blown fill have met with limited success. Typically, blow fiber is difficult to distribute evenly across the comforter shell during construction. In addition, blown fibers tend to clump during actual use, with these clumps being difficult to disentangle. This is especially true of mechanically crimped fibers such as those produced by the conventional stuffer box method. Such mechanically crimped fibers have a saw-tooth crimp structure with sharp nodes which act like Velcro®, and stick together. Thus, such fibers are more difficult to spread out initially, and tend to clump more during use. Clusters such as those disclosed in U.S. Pat. No. 4,618,531 have been tried in this end use but the success here has been hampered by the same problems as with blow fibers, i.e., difficulty in spreading and clumping. This is because these clusters according to the current state of the art have extraneous fibers protruding from the fiber balls and these fibers tend to entangle with the fibers of adjacent clusters. A further difficulty with all heretofore known blown, synthetic fills has been the propensity of the fillings to irreversibly clump during laundering. BRIEF SUMMARY OF THE INVENTION [0006] The present invention overcomes the problems of the prior art by providing filled articles, and in particular comforters, in which fiberfill easily spreads during construction and in which the fibers can be easily refluffed during use. [0007] Wash durability is also improved over other synthetic loose fill offerings. This is accomplished by the selection of a low denier fiber with a curvilinear crimp structure and a low fiber friction as the filling fiber. [0008] Thus, in accordance with the present invention, there is provided a filled article with a blown, non-clustered fiber having a denier per filament of 3 or less, a curvilinear crimp structure and a staple pad friction of less than 0.260. BRIEF DESCRIPTION OF THE DRAWING(S) [0009] [0009]FIG. 1 is an isometric view of a filled article according to the present invention. DETAILED DESCRIPTION OF THE INVENTION [0010] In accordance with the present invention, there is provided a filled article, such as a comforter 10 shown in FIG. 1, or a futon or cushion. The article comprises a blown, non-clustered fiber. By “non-clustered” is meant not having a randomly entangled, spherical shape. The fiber is a low denier per filament fiber, having a denier per filament of 3 or less. The fiber is super slickened, so that the when blown into a filled article, such as a comforter, the fibers slide over each other. This slickened quality is measured by staple pad friction, and the fiber of the present invention has a staple pad friction of less than 0.260. Also, the fiber of the present invention has by a curvilinear crimp structure. By “curvilinear” is meant that the synthetic filaments take up their helical configuration spontaneously during their formation and/or processing, as a result of differences between portions of the cross-sections of the filaments, as described in detail in U.S. Pat. No. 5,683,811. [0011] While a comforter per the present invention may be any size, a substantially rectangular, queen size bed comforter with dimensions 88″×96″ (223.5 cm×244 cm) will be discussed in detail. Referring to FIG. 1, a comforter, 10 , is formed by first opening and blowing fiber characterized as having a curvilinear crimp structure, a cut length less than 2.5″ (51 mm) and more preferably between 0.5″ (13 mm) and 1.5″ (38 mm) and having a staple pad friction of less than 0.260, and more preferably less than 0.225. Such opening is performed by mechanically separating the filaments one from another in a first stage process typically employing one or more multi-toothed rolls, referred to as opening or pre-opening. The opened fibers are then drawn into the suction of a blower from whence an appropriate amount is blown into a comforter shell positioned over the blowers discharge. This shell is formed by sewing the edges of two properly sized fabric sheets together along the periphery, 20 , of the sheets leaving an unsewn opening sized to accommodate the discharge of the blower. Alternatively, the comforter shell can be prestitched into channels by sewing the two sheets together in appropriately spaced, parallel lines 30 , in addition to the edge stitching while leaving one end perpendicular to the parallel stitching left unsewn. In this embodiment, the appropriate amount of filling would be blown into each channel. Following blowing, the opening of the comforter is sewn shut. At this point, the fiber is evenly distributed throughout the shell by redistributing the filling so as to force fiber from areas of an overabundance to areas lacking sufficient fill. This distribution can be performed in many ways either manually of with the assistance of a machine. After the fibers are essentially evenly distributed, the comforter is securely stretched into a frame designed to hold the comforter flat and taut. The framed comforter is then quilted by sewing the shell fabrics together, as shown at 30 and 40 in FIG. 1. The quilting pattern may be in any design provided the stitching forms hollow pockets or cells, 50 , between the shell fabrics essentially bounded on all sides by the stitching with each cell containing an appropriate amount of the filling fiber. Such quilting thus effectively locks the filling material into a general region of the comforter. [0012] As is illustrated by the following example, a comforter provided by this invention offers improvements in constructability due to the ease with which the fill can be distributed within the comforter shell. In addition and perhaps more importantly, the comforter so produced offers beneficial advantages in that the fill can be easily redistributed during actual use TEST METHODS [0013] The parameters mentioned herein are standard parameters and are mentioned in the art referenced herein, as are methods for measuring them. Since methods can vary, especially for measuring bulk, methods used herein are summarized briefly. [0014] Fiber Properties [0015] Properties of the fibers are mostly measured essentially as described by Tolliver in U.S. Pat. No. 3,772,137, and as referenced by Hernandez in U.S. Pat. No. 5,458,971. BL1 was the measurement made at 0.001 psi in Tolliver, and BL2 was the measurement made at 0.2 psi in Tolliver. These measurements are the TBRM (Total Bulk Response Method), as described in Tolliver. [0016] Crimp Frequency (CF) [0017] These measurements were made as described by Tolliver in U.S. Pat. No. 3,772,137. In the Tables that follow in the Examples hereinafter the measurements are given in crimps per inch. [0018] Staple Pad Friction [0019] Friction is measured by the SPF (Staple Pad Friction) method, as described hereinafter. As used herein, a staple pad of the fibers whose friction is to be measured is sandwiched between a weight on top of the staple pad, and a base that is underneath the staple pad and is mounted on the lower crosshead of an Instron 1122 machine (product of Instron Engineering Corp., Canton, Mass.). [0020] A staple pad is prepared by carding the staple fibers (using a SACO-Lowell roller top card) to form a batt which is cut into sections, that are 4.0 inches in length and 2.5 inches wide, with the fibers oriented in the length dimension of the batt. Enough sections are stacked up so the staple pad weighs 1.5 gm. The weight on top of the staple pad is of length (L) 1.88 inches, width (W) 1.52 inches, and height (H) 1.46 inches, and weighs 496 gm. The surfaces of the weight and of the base that contact the staple pad are covered with Emery cloth (grit being in 220-240 range), so that it is the Emery cloth that makes contact with the surfaces of the staple pad. The staple pad is placed on the base. The weight is placed on the middle of the pad. A nylon monofil line is attached to one of the smaller vertical (W×H) faces of the weight and passed around a small pulley up to the upper crosshead of the Instron, making a 90 degree wrap angle around the pulley. [0021] A computer interfaced to the Instron is given a signal to start the test. The lower crosshead of the Instron is moved down at a speed of 12.5 in/min. The staple pad, the weight and the pulley are also moved down with the base, which is mounted on the lower crosshead. Tension increases in the nylon monofil line as it is stretched between the weight, which is moving down, and the upper crosshead, which remains stationary. Tension is applied to the weight in a horizontal direction, which is the direction of orientation of the fibers in the staple pad. Initially, there is little or no movement within the staple pad. The force applied to the upper crosshead of the Instron is monitored by a load cell and increases to a threshold level, when the fibers in the pad start moving past each other. (Because of the Emery cloth at the interfaces with the staple pad, there is little relative motion at these interfaces; essentially any motion results from fibers within the staple pad moving past each other.) The threshold force level indicates what is required to overcome the fiber-to-fiber static friction and is recorded. [0022] The coefficient of friction is determined by dividing the measured threshold force by the 496 gm weight. Eight values are used to compute the average SPF. These eight values are obtained by making four determinations on each of two staple pad samples. [0023] Crimp Take-Up (CTU) [0024] Crimp take-up is measured by the rope crimp take up method as described below. [0025] Rope Crimp Take-Up [0026] A rope of known denier at least 1.5 meters in length is prepared for measurement by placing a knot in both ends. The resulting sample is subjected to a load of 125 mg/den. Two metal clips are placed across the extended rope at a distance apart of exactly 100 centimeters. The two ends of the rope are cut off within 1-2 inches beyond the clips. The resulting cut band is hung vertically and the recovered crimped length between the clips is measured to the nearest 0.5 centimeters. Crimp take-up is calculated using the following equation % CTU=A−B/A× 100 [0027] where A is the extended length, 100 centimeters, B is the retracted crimp length in centimeters. [0028] Clo Units [0029] The insulation of a textile system can be expressed in terms of a clo unit. The unit clo is normally used for expressing clothing insulation since it is related to clothing commonly worn, but may be used for other textiles. The value for 1 clo is defined by first considering that the resting metabolic heat production of an average man is about 50 kcal/m 2· h. Approximately 25% of this heat is lost via the respiratory system and by diffusion of moisture through the skin. Therefore, 38 kcal/m 2· h remains lost through the clothing via radiation, conduction, and convection. The temperature difference across the clothing is equal to the difference between the mean skin temperature (T s ) and the ambient air temperature (T a ), assuming the mean radiant temperature of the surroundings is equal to the air temperature. Consequently, a clothed person with a comfortable skin temperature of 33.3° C. (92° F.) in a comfortable environment at 21° C. (70° F.), has a 12° C. temperature gradient across which 38 kcal/m 2· h is transferred. A heat transfer coefficient of 0.32° C. m 2 ·h/kcal is calculated by dividing the temperature difference by the heat flow (i.e., 12/38). About 0.14 of the 0.32 total is contributed by the surrounding air layer, so 0.18 is contributed by the clothing alone. Thus 1 clo of insulation is equal to 0.18 m 2· ° Ch/kcal. EXAMPLE [0030] A comforter according to the present invention was prepared by first opening the baled fiber described in Table 1, Item A, through a Crompton and Knowles opener/blower. In this machinery, the compacted fibers were separated one from another in a first stage process typically referred to as opening or pre-opening. The opened fibers were then drawn into the suction of a blower from whence they were blown into a receiving receptacle held over the blower's discharge with the receiving receptacle typically taking the form of a pillow tick or comforter shell. In this Example, 40 oz. of the fiber was blown into the open end of an 88″ by 96″ comforter shell constructed of a 100% cotton, 312 thread count sateen fabric. Following blowing, the open end of the comforter was sewn shut. At this point, the closed comforter was spread across a flat table and the fiber was evenly distributed throughout the shell by manually redistributing the filling so as to force fiber from areas of an overabundance to areas lacking sufficient fill. Such redistribution was accomplished with the aid of a cylindrical rod applied as needed against the outside of the comforter shell. It was observed during this process that the fibers were more easily distributed than the fillings described in comparative Examples 1, 2, & 3 below. After the fibers were essentially evenly distributed, the comforter was transferred to a light table constructed such that a light source from below shines upward through the comforter and reveals any areas barren of fiber. The fibers were then finely adjusted to assure that they were evenly distributed throughout the comforter by applying pressure through the comforter shell as needed to propel fibers from areas of surplus to areas having insufficient fill. Following this adjustment, the comforter was securely stretched into a frame designed to hold the comforter flat and taut. The framed comforter was then passed through an automatic quilting machine which stitched through both sides of the comforter in a pattern to yield sewn cells with approximate 12″ by 12″ dimensions thus effectively locking the filling material into a general region of the comforter. TABLE 1 Denier per Crimp Cut Length Crimp per Staple pad Initial bulk, Support Bulk, Item filament (Dtex) Type * in. (mm) in. (C/cm) CTU friction BL-1 in. (cm) BL-2 In. (cm) A 2.0 (2.2) C  1.26 (32)  8.14 (3.2) >28 0.187 5.29 (13.44) 0.34 (.86) B 6.5 (7.2) C 1.125 (28) Unknown >38 0.245 5.70 0.43 C   7 (7.7) C  1.26 (32)  3.7 (1.46) unknown 0.284 5.90 0.61 D 1.1 (1.2) M 1.42 13.69 (34.8) unknown Unmeasurable unmeasurable unmeasurable Comparative Example 1 [0031] A comforter was constructed essentially as described in Example 1 with the exception that the fiber used was that shown in Table 1, item B. Comparative Example 2 [0032] A comforter was constructed essentially as described in example 1 with the exception that the fiber used was that shown in Table 1, item C. Comparative Example 3 [0033] A comforter was constructed essentially as described in Example 1 with the exception that the fiber used was that shown in Table 1, item D which is the commercially available Primaloft® comforter marketed by Albany International, Inc. [0034] Following construction, comforters produced per Example 1 and comparative Examples 1, 2, and 3 were evaluated for warmth, tactile aesthetics and wash durability. Warmth data is shown in Table 3. TABLE 3 Thermal Avg. Fill Avg. Conductivity Density thickness per unit oz/yd 2 at 0.002 weight Item (g/m 2) psi load Clo/oz/yd 2 A Ex. 1 7.22 (245)  1.3 (3.3) 0.247 B Comp 1 5.69 (193) 1.20 (3.0) 0.196 C Comp 2 6.18 (210) 1.26 (3.2) 0.197 D Comp 3 7.29 (247)  1.3 (3.3) 0.271 [0035] As can be seen, the thermal conductivity of Example 1 is superior to that of the other curvilinear crimp items and rivals that of comparative Example 3 despite the higher denier and thus lower radiant shielding of example one. [0036] Regarding tactile aesthetics, the comforter of Example 1 was found to respond much more similarly to the preferred down comforters in that the filling was more free to move within each quilted comforter cell vs. the comparative examples. As is typical for down comforters and other loose fill comforters and contrary to the performance observed with typical synthetic batting comforters, drapability of Example 1 and comparative Examples 1, 2, and 3 as determined by any conventional method is primarily set by the stiffness of the shell material. This property is due to the proclivity of the loose fill to gravitate toward the lower portion of each quilted cell as the comforter is allowed to hang vertically over the edge of a bed or other horizontal surface thus leaving only shell fabric at the comforter's point of inflection. The comforter of example 1 was found to be capable of having it's fill material redistributed from these lower cell portions to once again evenly fill the said cells by merely applying a gentle shaking action to the edge of the comforter adjacent to the maldistributed cells. By comparison, comparative Examples 1, 2, and 3 each required a vigorous shaking of the comforter cells with occasional manual manipulation of the fill through the shell. [0037] After being subjected to 3 laundry cycles in a commercial, front loading washing machine using Tide powder as a detergent with subsequent drying between each cycle in a commercial electric clothes dryer, the comforters of example 1 and comparative Examples 1, 2, and 3 were observed for wash durability. The qualitative results are shown in Table 3. TABLE 3 Rank relative Comforter to others Pass/Fail Item observation Fill observation in test rating A Example 1 Slightly lumpy, Slightly 1 Pass Fill easily entangled respread B Comp 1 Lumpy, filling Cluster like 2 Fail respreadable but entanglements. comforter looses loft during respreading C Comp 2 Lumpy, filling Matted with 3 Fail respreadable but large cluster comforter looses like loft during entanglements respreading D Comp 3 Lumpy, Difficult Fiber entangled 4 Fail to respread into twisted structures

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BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to oil supply systems for internal combustion engines and in particular, to an improved oil distribution and supply system through the crank shaft to the, main bearings and rod bearings in an internal combustion engine. 2. Description of the Prior Art Supplying oil to bearings in a crank shaft in a modern internal combustion engine is critical to the performance of the engine and the longevity of the parts of the engine. In particular, modern day V-6 engines have had some problems with the oil supply. Typically, in a V-6 internal combustion engine such as the type sold by General Motors Corporation and placed in BUICK vehicles, the main bearings on the crank shaft have half grooves disposed partially around the crank shaft which are supplied with oil under pressure from an oil pump. The result is a pulsating oil supply to the rod bearings because of the rotation of the crank shaft which has internal passageways which pass through the groove areas in the bearing to be replenished only during 180 degrees of the rotation of the crank shaft. The end result is that a continuous supply of oil is not provided to the rod bearings during each crankshaft rotation. It is not uncommon that the rod bearings fail in these engines. The purpose of the present invention is to provide an improved oil distribution system in a crank shaft for a V-6 engine or any other engine that provides for a continuous supply of oil to the rod bearings and enhances the lubrication at the thrust bearing and eliminates the pulsating effect of the oil distribution throughout the crank shaft. SUMMARY OF THE INVENTION An oil distribution system for use in an internal combustion engine crank shaft for supplying oil continuously to the rod bearings disposed along the crank shaft, comprising a crank shaft useful for a V-6 engine, having six rod journals and six rod bearings attachable thereto and four main bearings attachable thereto, said crank shaft including a first oil supplying passage disposed from a peripheral position on the crank shaft main journal linearly until it reaches an outlet at the rod journal, each of said main journals having linear oil delivering passages having an opening at the main journal and an outlet at each rod journal. These first linear oil passages extending from the main journals to the rod journals are the main oil supply passages used in conventional V-6 crank shafts. The crank shaft further includes, disposed at 180 degrees to the first passage, a second passage drilled angularly from the main journal intersecting the first passage, said first and second passage inlets being 180 degrees apart on the main journal. Each main journal includes a main bearing that has 180 degree grooved section about one portion and a non-groove section about the other portion. The inner main journals, of which there are two, include yet an additional passage from the main journal to the adjacent rod journal. These second oil passages extending from the main journals, 180 degrees out from the first oil passages, to the first oil passages are the secondary oil passages critical to the present invention. Thus, the two outside main journals have one singular linear passage and an adjacent passage connected thereto 180 degrees out. The two inner crank shaft main journals include three passages, two of which commence from the main journal 180 degrees out from the third linear journal passage and connected thereto and to each other. A conventional oil pump is used with the crank shaft installed. In operation, oil will flow under pressure into each of the upper main bearings and the groove in those bearings, where the oil is distributed through each rotational 180 degrees down one of the passages. In other words, an oil distribution passage opening is always present in the main bearing groove so that there will be a continuous flow of oil under pressure to the rod bearings. Oil is thus continuously distributed to the adjacent rod bearing in each case. In the case of the two inner main bearings, oil is continuously provided to both adjacent rod bearings on each side. Lubricating motor oil under pressure is forced from the pump through a small hole in the top of each main bearing, where it is distributed along 180 degrees of the bearing within the main bearing groove. Disposed 180 degrees from each other is the inlet of each oil dispersing passage, so that as it passes through the groove portion of the main bearing, the oil under pressure is forced into the inlet opening along the passage, terminating in the adjacent rod journal and rod bearing. Thus, it can be seen that oil is always under pressure to each of the rod bearings, insuring that they are not prematurely damaged from oil starvation. It is the objective of this invention to provide an improved oil distribution system for a crank shaft constructed from lightweight, relatively inexpensive materials such as cast iron, and especially to provide continuous oil flow to rod journals and bearings. It is another objective of this invention to provide an after-market correction on V-6 engines to improve the oil distribution of the engine by modifying the crank shaft with additional oil distribution passages. And yet still another objective of this invention is to provide an improved V-6 engine with improved performance through modifications without reduced oil pressure to the oil distribution system. Another objective of the invention is to distribute as much oil as possible to the lower half of the engine. In accordance with these and other objectives which will become apparent hereinafter, the instant invention will now be described with particular reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a prior art side elevational view of a V-6 crank shaft partially in cross section, showing the previous oil distribution system. FIG. 2 shows a side elevational view, partially in cross section, of a V-6 crank shaft and oil distribution system in accordance with the present invention. FIG. 3 shows a front elevational view, schematically representing a conventional V-6 crank shaft. DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings and in particular FIG. 1, a conventional V-6 engine crank shaft, of the type sold by General Motors Corporation for its BUICK vehicles, is shown at 12 in a side elevational view, partially schematic. The dotted passages 26, 28, 30, 32, 34, and 36 represent straight-line, cylindrical, bored-out passageways that transmit oil from the upper main bearings B1, B2, B3, and B4, through main journals M1, M2, M3, and M4 and through rod journals R1, R2, R3, R4, R5, and R6, to adjacent rod bearings RB1, RB2, RB3, RB4, RB5, and RB6. Each upper main bearing B1, B2, B3, and B4 includes, respectively, a 180 degree groove 38, 40, 42, and 44 that have apertures 60, 62, 64, and 66 disposed therein which receive oil under pressure from the engine oil pump (not shown) through oil passages 46, 47, 48, and 49. Thus, within each groove 38, 40, 42, and 44 is oil under pressure as the crank shaft 12 rotates. Note that each first, or main, oil passage, such as 26, has an inlet that opens into upper main bearing B1 groove 38 for 180 degree traverse of the rotating crank shaft 12. During that time, oil under pressure goes down passage 26, through main journal M1 and through rod journal R1, to where it exits at journal R1 onto rod bearing RB1. Note that oil will only be able to flow under pressure during the 180 degree segment where the opening to passageway 26 is within the groove 38 for 180 degree rotation of the crank shaft. When the opening to passage 26 is adjacent the nongroove portion of bearing B1, no oil is flowing and rod journal R1 does not get oil under pressure. Thus, it can be seen with each of the upper main bearings B1, B2, B3, B4, which function the same way, oil is pulsating for 180 degree segment. The end result is that there is not a continuous distribution of oil to the rod bearings RB1, RB2, RB3, RB4, RB5, and RB6, which can result in failure of the rod journals R1, R2, R3, R4, R5, and R6, then the crank shaft and engine. The present invention is shown in FIG. 2 with a solution that provides for continuous oil flow under pressure to the rod journals and rod bearings. With respect to main journal M1, there is an additional angular secondary oil passage 50 which is 180 degrees out at its opening from passage 26 and intersecting with passage 26. Therefore, oil under pressure in the main bearing groove 38 will be flowing under pressure either into passage 26 or passage 50, whichever has its opening disposed in the bearing groove 38. This insures that oil under pressure will always arrive at rod journal R1 and be constantly supplied to rod bearing RB1. With respect to the main journal M2, additional angular secondary oil passage 52 in conjunction with first or main passage 28 provides for continuous oil flow under pressure to rod journals R2 and R3, and thus rod bearings RB2 and RB3, commencing either from passage 28 or passage 52. With respect to main journal M3, additional angular passage 54 in conjunction with passage 34 provides for continuous oil flow under pressure to rod journals R4 and R5 and thus rod bearings RB4 and RB5 commencing either from passage 34 or passage 54. Finally, with respect to main journal M4, additional angular passage 56 in conjunction with passage 36 provides for continuous oil flow under pressure to rod journal R6 and thus rod bearing RB6 commencing either from passage 36 or passage 56. FIG. 2 also shows oil passages 46, 47, 48, and 49 that supply oil under pressure from the engine oil pump (not shown) to main bearings B1, B2, B3, and B4, respectively, through apertures 60, 62, 64, and 66 into grooves 38, 40, 42, and 44, respectively. Note from the construction of the additional oil passages in FIG. 2, which are disposed angularly 180 degrees out from the conventional passage, that this work could be done in an after-market product with the crank shaft removed from a conventional V-6 engine and the additional oil passages drilled or bored into the crank shaft. FIG. 3 shows the conventional spacing of the rod bearings around the crank shaft in a conventional Buick V-6 engine. Utilizing the present invention, which is a fairly non-complex modification, the overall engine efficiency can be greatly improved and potential future damages to these engines alleviated and the engine life greatly increased with such modifications. The instant invention has been shown and described herein in what is considered to be the most practical and preferred embodiment. It is recognized, however, that departures may be made therefrom within the scope of the invention and that obvious modifications will occur to a person skilled in the art.

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This application is the US national phase of international application PCT/IT2004/000374 filed 6 Jul. 2004 which designated the U.S. and claims benefit of IT RM 2003 A 000344 filed 14 Jul. 2003, the entire contents of each of which are hereby incorporated by reference. The invention disclosed herein relates to compounds useful as medicaments, and particularly to camptothecin derivatives with substituents in position C-7, containing polyamine residues in which the amine residues are protected with protective groups such as Boc, to processes for their preparation, to their use as active agents with topoisomerase I inhibiting activity and to pharmaceutical compositions containing them as active ingredients. BACKGROUND TO THE INVENTION Camptothecin is an alkaloid isolated by Wall et al. [ J. Am. Chem. Soc., 1966, 88, 3888-3890] for the first time from the tree Carmptotheca acumiiata , native to China and belonging to the Nyssaceae family. The molecule consists of a pentacyclic structure with a lactone in ring E, which is essential for cytotoxicity. For a review of the camptothecins and the problems relating to their use as medicaments as well as the solving of such problems, the reader is referred to EP 1 044 977, filed in the name of the present applicants. The polyamines have for some time now been the subject of great interest in medicinal chemistry. Putrescine, spermidine and spermine are the most intensively studied polyamines, in that they occur naturally in both prokaryotic and eukaryotic cells. Their role in cell physiology would appear to be multiple and, in certain respects, still unknown [ J. Med. Chem., 2001, 44, 1-26]. At physiological pH these compounds are present as polycations, are capable of interacting with a substantial variety of cell constituents, such as RNA, DNA, nucleotides, proteins and other biological substances of an acid nature [ J. Cell Biochem., 1991, 46, 37-47]. In oncology the polyamines are the subject of study for a number of reasons, namely, their polycationic nature at physiological pH, their influence on the ion channels of the cell membranes, and their interaction with various important transcriptional factors in human tumour forms [ Biochemistry 1999, 38, 14765-74]. The conjugation of polyamines with cytotoxic drugs has also been described, for example with chlorambucil [ Cancer Res., 1992, 52, 4190-5], where a substantial improvement in the therapeutic index has been observed, but also as a form of chemoprevention in combination with 3-indolylcarbinol [ BMC-Cancer 2003, 3:2, 1471-2407]. Less frequent is the study of polyamine derivatives in protected form: for example, N-benzyl-derivatives [ J. Med. Chem., 2001, 44, 3653-64]. The polyamines can be bound to cytotoxic molecules in order to influence their cell transport: for example, spermines have been conjugated with acridines [ J. Med. Chem., 2002, 45, 5098-111] for the purposes of favouring a selective release of the latter at tumour cell level. Polyamine residues have also been inserted in camptothecins (CPT) in position 7, such as iminomethyl derivatives [ Bioorganic & Medicinal Chemistry Letters, 2001, 11, 291-4], and, in particular, the compound derived from spermine has been described in international patent application WO 0053607 filed in the name of the present applicant. SUMMARY OF THE INVENTION It has now been surprisingly found that camptothecins substituted in position 7 by means of an iminomethyl or oxyiminomethyl bond, where the imine and oxime groups derive from amines or hydroxylamines containing polyaminoalkyl residues (e.g. spermine, spermidine, putrescine), when present in protected form, display substantial anticancer activity, distinctly superior to that of the same derivatives in unprotected form. This anticancer potency is comparable to that of compounds currently used in oncological clinical practice, and therefore the derivatives which are the subject of the present invention may make a major contribution to enriching the armamentarium available for the fight against cancer. The compounds which are the subject of the present invention have the following general formula (I): in which m is the number 0 or 1; Z and Z′, which can be the same or different, are an integer ranging from 0 to 2; Y and Y′, which can be the same or different, are (CH 2 )n 1 ; (CH 2 )n 2 -CH[NR VII (CH 2 )n 4 -NHR 1 ]—(CH 2 )n 3 ; CH 2 —CH[CH 2 —CH 2 ] 2 — or (CH 2 )n 2 N[(CH 2 )n 4 —NHR IV ]—(CH 2 )n 3 ; Y″ is selected from the group consisting of H; cycloalkyl C 3 -C 7 ; (CH 2 )n 5 -N[CH 2 —CH 2 ] 2 N—(CH 2 )n 6 NHR V ; (CH 2 )n 7 -CH[CH 2 —CH 2 ] 2 NR V ; X is O, or is a simple bond; n-n 8 , which can be the same or different, are an integer ranging from 0 to 5; R I , R II , R III , R IV , and R V , which can be the same or different, are a protective group for the nitrogen to which they are bound; CO 2 R VI ; CO 2 CH 2 Ar; CO 2 (9-fluorenylmethyl); (CH 2 )n 5 -NHCO 2 R VI ; CH 2 Ar; COAr; (CH 2 )n 5 -NHCO 2 CH 2 Ar; (CH 2 )n 5 -NHCO 2 -(9-fluorenylmethyl). R VI is a straight or branched (C 1 -C 6 ) alkyl; R VII is H or R I -R V ; Ar is a C 6 -C 12 aromatic residue, such as phenyl, optionally substituted with one or more groups selected from: halogen, hydroxy, C 1 -C 5 alkyl, C 1 -C 5 alkoxy, phenyl, cyano, nitro, —NR VIII R IX , where R VIII and R IX , which can be the same or different, are hydrogen, straight or branched (C 1 -C 5 ) alkyl, or Ar is a heterocyclic group, said heterocyclic group containing at least one heteroatom selected from a nitrogen atom, optionally substituted with a (C 1 -C 5 ) alkyl group, and/or oxygen and/or sulphur; said heterocycle can be substituted with one or more groups selected from halogen, hydroxy, C 1 -C 5 alkyl, C 1 -C 5 alkoxy, phenyl, cyano, nitro, —NR VIII R IX , where R VIII and R IX , which can be the same or different, are hydrogen, straight or branched (C 1 -C 5 ) alkyl, the N 1 -oxides, racemic mixtures, their individual enantiomers, their individual diastereoisomers, the E and Z forms, their mixtures, and pharmaceutically acceptable salts. The present invention comprises the use of compounds with the above-mentioned general formula (I) as active ingredients for medicaments, particularly for medicaments useful as topoisomerase I inhibitors. Among the therapeutic applications deriving from the topoisomerase inhibiting activity we should mention tumours and viral and parasite infections. The present invention comprises pharmaceutical compositions containing formula (I) compounds as active ingredients, in admixture with pharmaceutically acceptable vehicles and excipients. DETAILED DESCRIPTION OF THE INVENTION What is meant by a protective group, as referring to the various R I , R II , R III , R IV , and R V , is a group that favours the capture of the molecule by the cell. Whereas the present invention is based on the discovery that protective groups on the amine nitrogens confer potent anticancer activity upon the molecules, and since the inventors do not wish to be tied to any particular theoretical consideration, it is believed that the protective groups should be bulky groups of a lipophilic nature. Preferred examples of protective groups are: CO 2 R VI ; CO 2 CH 2 Ar; CO 2 -(9-fluorenylmethyl); (CH 2 )n 5 -NHCO 2 R VI ; (CH 2 )n 5 NHCO 2 —CH 2 Ar; CH 2 Ar; COAr; (CH 2 )n 5 -NHCO 2 -(9-fluorenylmethyl), in which the variable groups are defined as above. A first group of particularly preferred compounds comprises formula (I) compounds with a 6-term lactone ring (m=0) and, among these, particularly: tert-butylester of 20S-(4-{[3-(7-camptothecinylidene-amino)-propyl]-tert-butoxycarbonyl-amino}-butyl)-(3-tert-butoxycarbonyl-aminopropyl)-carbamic acid; tert-butylester of 20S-(4-{[3-(7-camptothecinylidene-amino)-propyl]-tert-butoxycarbonyl-amino}-butyl)-carbamic acid; tert-butylester of 20S-[3-(7-camptothecinylidene-amino)-butyl]-carbamic acid; 20S-7-[3-(T-tert-butoxycarbonylamino)propoxyimino-methyl]-camptothecin. A second group of preferred compounds comprises formula (I) compounds with a 7-term lactone ring, the synthesis of which is described in [ J. Med. Chem. 1993, 41, 5410], and, among these, particularly: tert-butylester of 20RS-(4-{[3-(7-homocamptothecinylidene-amino)-propyl]-tert-butoxycarbonyl-amino}-butyl)-(3-tert-butoxycarbonylaminopropyl)-carbamic acid; tert-butylester of 20RS-(4-{[3-(7-homocamptothecinylidene-amino)-propyl]-tert-butoxycarbonyl-amino}-butyl)-carbamic acid; tert-butylester of 20RS-[3-(7-homocamptothecinylidene-amino)-butyl]-carbamic acid; 20R,S-7-[3-(N-tertbutoxycarbonylamino)propoxyimino-methyl]-homocamptothecin. The compounds disclosed in the present invention are topoisomerase I inhibitors and are therefore useful as medicaments, particularly for the treatment of diseases that benefit from inhibition of said topoisomerase. In particular, the compounds according to the present invention display antiproliferative activity, and are therefore used for their therapeutic activity, and possess physicochemical properties which make them suitable for formulation in pharmaceutical compositions. The pharmaceutical compositions contain at least one formula (I) compound as the active ingredient, in an amount such as to produce a significant therapeutic effect. The compositions covered by the present invention are entirely conventional and are obtained by using methods which are common practice in the pharmaceutical industry. According to the administration routes opted for, the compositions will be in solid or liquid form, suitable for oral, parenteral or intravenous administration. The compositions according to the present invention contain, along with the active ingredient, at least one pharmaceutically acceptable vehicle or excipient. These may be particularly useful coadjuvants, for example, solubilising agents, dispersion agents, suspension agents, or emulsifying agents. Formula (I) compounds can also be used in combination with other active ingredients, for example, anticancer drugs or other drugs with antiparasite or antiviral activity, both in separate forms and in single-dosage forms. The compounds according to the present invention are useful as medicaments with anticancer activity, for example in lung cancers such as non-microcytoma lung cancer, or in colorectal and prostate cancer and glioma. The following examples further illustrate the invention. Preparation 1 7-Formyl-camptothecin To a solution of 2.0 g (4.73 mmol) of 7-dimethylacetal-camptothecin in 18 mL of CH 2 Cl 2 , cooled to 0° C., were added 12 mL of TFA and a few drops of H2O. After one night at room temperature the reaction is complete with the formation of a product with Rf=0.42 (CH 2 Cl 2 /MeOH 92:8). The reaction mixture was purified by chromatography on SiO 2 with CH 2 Cl 2 /MeOH (from 98:2 to 92:8) to give 1.4 g (3.72 mmol; yield 79%) of the expected product as a yellow solid. Preparation 2 N′,N″,N′″-triBoc-spermine N′,N″,N′″-triBoc-spermine was prepared according to the process described in the literature [ Tetrahedron Letters 1998, 39, 439-42]. Preparation 3 N′,N″-diBoc-spermidine The compound was prepared with a process equivalent to that disclosed for spermine. Preparation 4 N′-Boc-putrescine This compound is commercially available EXAMPLE 1 7-[(N′,N″,N′″-tert-butoxycarbonyl)-spermine-imino-methyl]-20S-camptothecin [ST2544]. 272 mg (0.72 mmol) of 7-formylcamptothecin were dissolved in 20 mL of anhydrous CH 2 Cl 2 in a 100 mL flamed flask. 44 mg of Yb (OTf) 3 (0.07 mmol; 0.1 eq.) were added to the solution and then 700 mg (1.4 mmol; 2 eq.) of tri-Boc-spermine dissolved in 12 mL of anhydrous CH 2 Cl 2 and molecular sieves, keeping the reaction flask sheltered from the light. After 16 h at room temperature 1.9 g (4.2 mmol; 3 eq. in relation to spermine) of a resin functionalized with isocyanate groups (loading 2.2 mmol/g) were added as a scavenger of the excess amine. The reaction mixture was left for another 16 h at room temperature before being filtered on celite to remove the molecular sieves and the scavenger resin; the solvent was removed in vacuo and the crude reaction product was purified by preparative HPLC chromatography (CH 3 CN/MeOH=90:10; 8 mL/min; RP-18, 250×25 mm, 7 μm) to give 500 mg (0.58 mmol; yield 81%) of product as a yellow solid. MS(IS):[MH] + =860.8 [M−1] − =858.7 1 H NMR (300 MHz, CDCl 3 , δ): 1.0-1.1 (t, 3H, CH 3 ), 1.4-2.0 (m, 35H, 3×tBu+4×CH 2 ), 2.0-2.1 (q, 2H, CH 2 ), 3.0-3.3 (m, 10H, 5×CH 2 ), 3.85-3.95 (d, 2H, CH 2 ), 5.3-5.4 (d, 1H, CH), 2.55 (s, 2H, CH 2 ), 5.75-5.85 (d, 1H, CH), 7.7-7.9 (m, 3H, 3×CH), 8.25-8.35 (d, 1H, CH), 8.45-8.55 (d, 1H, CH), 9.4 (s, 1H, CH). 13 CNMR (75.4 MHz, CDCl 3 , δ): 8.0; 28.6; 28.7; 31.8; 47.0; 52.7; 66.6; 72.9; 79.5; 97.8; 118.9; 126.2; 127.6; 128.5; 139.3; 130.8; 146.2; 149.9; 150.0; 152.9; 155.7; 157.6; 174.0. EXAMPLE 2 7-[(N′, N″-tert-butoxycarbonyl)-spermidine-imino-methyl]-20S-camptothecin [ST2598]. Using the same process disclosed in Example 1, the title product was obtained. Yield=22% MS(IS): [MH] + =704.6 [M+Na] + =726.6 1 H NMR (300 MHz, CDCl 3, δ): 1.0-1.1 (t, 3H, CH 3 ), 1.4-2.1 (m, 26H, 2xtBu+4×CH 2 ), 3.0-3.4 (m, 4H, 2×CH 2 ), 3.75-3.95 (m, 4H, 2×CH 2 ), 5.25-5.35 (d, 1H, CH), 5.55 (s, 2H, CH 2 ), 5.75-5.85 (d, 1H, CH), 7.7-7.9 (m, 3H, 3×CH), 8.25-8.35 (d, 1H, CH), 8.45-8.55 (d, 1H, CH), 9.4 (s, 1H, CH). 13 CNMR (75.4 MHz, CDCl 3 , δ): 8.0; 28.6; 28.7; 32.1; 47.4; 51.7; 52.9; 53.6; 66.7; 69.7; 72.9; 79.7; 98.0; 98.4; 119.0; 122.5; 123.1; 126.4; 127.7; 128.6; 130.2; 130.4; 131.0; 131.3; 146.4; 150.1; 153.1; 156.0; 156.4; 157.9; 174.2. EXAMPLE 3 7-[3-(N-tert-butoxycarbonyl)-amino-1-propoxyiminomethyl]20S-camptothecin (ST2664) To a suspension of -7-(3-aminopropoxyiminomethyl)-20S-camptothecin (20 mg, 0.045 mmol) in 5 ml of anhydrous THF are added 10 mg of (Boc) 2 O (1 equivalent) and 7 μl of Et 3 N (1 equivalent); the mixture is left to react at room temperature for 30 h, at the end of which period the reaction is almost complete. The reaction is monitored by TLC, eluting with CH 2 Cl 2 :CH 3 OH=9: 1. The THF is evaporated and the solid extracted with CH 2 Cl 2 ; the organic phase is washed with water (twice) and with brine (once). The solution is anhydrified with Na 2 SO 4 , filtered and brought to dryness. 16 mg of product consisting of a mixture of E and Z isomers is obtained (yield: 64%). Rf: 0.38 in CH 2 Cl 2 :CH 3 OH=98:2. M.p.: 141-142° C. 1 H-NMR (300 MHz, DMSO-d6, δ): 0.87 (t, H 3 −18E+H 3 −18Z), 1.37 (s, H 9 t-butyl E), 1.30 (s, H 9 t-butyl Z), 1.67 (m, H 2 -19Z+—CH 2 CH 2 CH 2 -Z), 1.87 (m, H 2 -19E+—CH 2 CH 2 CH 2 -E), 2-83 (t, CH 2 —N-Z), 3.07 (t, CH 2 —N-E), 4.12 (t, CH 2 —O-Z), 4.35 (t, CH 2 —O-E), 5.17 (s, H-17-Z), 5.32 (s, H-17-E), 5.40 (s, H-5-E), 6.50 (s, OH-E+OH-Z), 6.75 (t, NH-Z), 6.90 (t, NH-E), 7.25 (s, H-14-Z), 7.32 (s, H-14-E), 7.75 (m, H-11-E+H-11-Z), 7.90 (m, H-10-E+H-10-Z), 8.02 (d, H-12-Z), 8.20 (d, H-12-E+H-9-Z), 8.40 (s, —CH═N-Z), 8.6 (d, H-9-E), 9.32 (s, —CH═N-E). E:Z ratio=88:22 (by NMR). EXAMPLE 4 7-[N-(N′-tert-butoxcarbonyl)-putrescinimino-methyl]-20S-camptothecin [ST26151] Using the same synthesis process disclosed in Example 1, the title product was obtained. Yield=78% MS(IS):[MH] + =547.7 1 H NMR (300 MHz, CDCl 3 , δ): 1.0-1.1 (t, 3H, CH 3 ), 1.45 (s, 9H, tBu), 1.65-2.0 (m, 4H, 2×CH 2 ), 3.2-3.35 (q, 2H, CH 2 ), 3.9-4.0 (t, 2H, CH 2 ), 5.3-5.4 (d, 1H, CH), 5.55 (s, 2H, CH 2 ), 5.75-5.85 (d, 1H, CH), 7.7-7.9 (m, 3H, 3×CH), 8.25-8.35 (d, 1H, CH), 8.45-8.55 (d, 1H, CH), 9.4 (s, 1H, CH). EXAMPLE 5 7-[4-(N-tert-butoxycarbonyl)-piperidinyl-methyliminomethyl-20S-camiptothecin [ST2665) To a suspension of 7-formylcamptothecin (60 mg, 0.159 mmol) in 5 ml of CH 2 Cl 2 (distilled on CaCl 2 and conserved on sieves) are added 119 mg (0.477 mmol, 3 eq.) of 1-Boc-4-aminomethylpiperidine hydrochloride, 40 μl of pyridine and 6 mg of Yb(OTf) 3 (10% by weight in relation to the aldehyde) and the mixture is left to react at room temperature for 5 days (TLC: CH 2 Cl 2 :CH 3 OH=98:2). The product is purified by flash chromatography (eluent: CH 2 Cl 2 :CH 3 OH=99:1). Yellow solid. Yield: 20%. M.p. 200° C. dec. Rf of the reaction product: 0.37 in CH 2 Cl 2 :CH 3 OH=96:4. 1 H-NMR (300 MHz, DMSO-d 6 ; δ): 0.87 (t, CH 2 CH 3 ), 1.32 (s, t-butyl), 1.67-2.00 (m, CH 2 CH 3 +2—CH 2 pip.+—CH pip.), 2.55-2.85 (m, —CH 2 -pip.), 3.80 (m, —CH 2 —N), 3.97 (m, —CH 2 -pip.), 5.35 (s, H-17), 5.42 (s, H-5), 6.50 (s, OH), 7.35 (s, H-14), 7-70-7.80 (m, H-11), 7.85-7.95 (m, H-10), 8.20 (dd, H-12), 8.72 (dd, H-9), 9.42 (s, —CH═N). EXAMPLE 6 7-[(N′,N″-Di-benzyloxycarbonyl)-spermidineiminomethyl]-20S-camptothecin [ST2729]. Using the same synthesis process disclosed in Example 1, the title product was obtained. Yield=35% MS(IS): [MH] + =772.9 [M+Na] + =794.9 1 H NMR (300 MHz, CDCl 3 , δ): 1.0-1.1 (t, 3H, CH 3 ), 1.4-2.1 (m, 8H, 4×CH 2 ), 3.2-3.6 (m, 6H, 3×CH 2 ), 3.95 (s, 2H, CH 2 ), 5.1-5.2 (d, 4H, 2×CH 2 ), 5.4-5.9 (m, 4H, 2×CH 2 ), 7.2-7.45 (m, 10H, 10×CH), 7.7-7.9 (m, 3H, 3×CH), 8.25-8.5 (m, 2H, 2×CH), 9.4 (s, 1H, CH). 13 CNMR (75.4 MHz, CDCl 3 , δ): 8.0; 27.2; 31.7; 41.0; 52.8; 66.5; 66.6; 67.2; 72.9; 98.0; 118.9; 122.8; 126.2; 127.4; 127.8; 128.0; 128.2; 128.5; 130.3; 130.9; 136.7; 146.0; 150.0; 152.9; 156.3; 156.7; 157.7; 174.0 EXAMPLE 7 7-[3-(4-tert-butoxycarbonyl)aminobutyl)-tert-butoxycarbonylamino-propoxyiminomethyl]-20S-camptothecin [ST2872]. N″,N′″-(ditert-butoxycarbonyl)-aminobutylaminoethoxyamine (NMR (CDCl 3 ): 4.65 (NHBoc), 3.9 (CH 2 —O), 3.3-3.6 (Boc-N-CH 2 and —ONH 2 ), 3.05-3.25 (CH 2 NHBoc and CH 2 N-Boc), 1.45-1.55 (CH 2 —CH 2 ), 1.45 (18 H, 2 Boc) (200 mg) was prepared from N-Boc-4-aminobutanol (500 mg), via mesylation followed by reaction with ethanolaminie, Boc protection of the free NH group, Mitsunobu reaction with N-hydroxyphthalimide, and hydrazinolysis. 7-Formylcamptothecin (55 mg, 0.145 mmol) was dissolved in 2 ml of ethanol, added with 100 mg of N″,N′″-(ditert-butoxycarbonyl)-aminobutylaminoethoxyamine in 1 ml of ethanol, and refluxed 8 hr. Evaporation and chromatography on silica gel with dichloromethane:MeOH (97:3) gave 51 mg (50%) of the title compound, mp 153° C., R f 0.2 in CH 2 Cl 2 :MeOH (97:3), NMR (DMSO-d 6 ): 9.4 (s, CH═), 8.85 1 H-NMR (300 MHz, CDCl 3 , δ): 0.87 (t, H 3 -18E+H 3 -18Z), 1.45-1.65 (m, BOC E+BOC Z+—CH 2 CH 2 -Z+CH 2 CH 2 -E), 1.87 (m, H 2 -19E+H 2 -19Z), 2-80-3.65 (m, 3 CH 2 -N-Z+3 CH 2 -N-E), 4.25-4.35 (m, CH 2 —O-Z), 4.40-4.52 (m, CH 2 —O-E), 4.60 (brs, NH), 5.10 (brs, -NH), 5.20-5.45 (m, H-17-Z+H-17-E+H-5-Z), 5.65-5.75 (m, H-5E), 7.65-7.75 (m, H-14-Z+H-14-E+2Ar Z), 7.75-7.85 (m, 2Ar-E), 7.90 (d, 1ArZ), 8.05 (s, —CH═N-Z), 8.25-8.35 (m, 2ArE+1Ar Z), 9.05 (s, —CH═N-E). E:Z ratio=55:45 (by NMR). Cytotoxic activity on NCl—H460 cells NCl—H460 non-microcytoma lung cancer cells were kept in RPMI 1640 culture medium containing 10% FCS and 1% glutamine. The cytotoxicity test to analyse the activity of the molecules was performed as follows. The cells were seeded in a volume of 250 μl in 96-well plates and incubated for 2 hours at 37° C. with scalar concentrations of the products in a humidified atmosphere containing 5% CO 2 . At the end of the incubation, the molecules were removed by overturning the plates and adding sterile buffered saline solution (PBS) three times. The RPMI 1640 culture medium containing 10% FCS (200 μl) was added to the wells and the plates were incubated for another 72 hours. At the end of the incubation, the plates were overturned again and dried on paper, before adding 200 μl of PBS and 50 μl of 80% TCA. The plates were incubated again in ice for at least 1 hour. The TCA was removed by overturning the plates and the plates were first dried on paper and then washed three times by immersion in distilled water and overturning. The plates were dried first on paper and then in a thermostatically regulated incubator at 60° C. for 10 min. 200 μl of 0.4% sulforodamine B in 1% acetic acid were added to all wells. The plates were incubated at room temperature for another 30 min. The sulforodamine B was removed by overturning, the plates were washed by immersion in 1% acetic acid three times and then dried first on blotting paper and then in the thermostat at 60° C. for 10 min. Lastly, 200 μl of Tris base 10 mM were added to all wells and the plates were subjected to stirring for at least 20 min. The optical density was measured with a Multiskan spectrophotometer at 540 nm. Incubation with the products was capable of inhibiting proliferation in a concentration-dependent manner. Table 1 presents the IC 50 values (product concentration that inhibits cell survival by 50%]. ST2544 and ST2598 showed comparable, very potent cytotoxicity on the lung cancer line used. The results are presented in the following table. TABLE 1 Cytotoxicity of camptothecin derivatives Compound IC 50 (nM ± SD) ST2544 12.9 ± 1.8 ST2598 15 ± 2 ST2615 >200 ST2664 >200 ST2665 >200 ST2729 34 ± 7 ST2872 >200 Effect on Saccharornzces cerevisiae yeast model in vitro and in vivo To identify camptothecin derivatives that overcome the resistance to camptothecin induced by point mutations on topisomerase I DNA in the Saccharomyces cerevisiae yeast model, an in-vivo and an in-vitro system were used in parallel. For the in-vivo system, the yeast strain EKY3 (top1Δ) was transformed with YCpGAL1 plasmids as control and with different plasmids containing the mutants (YCpGAL1-hT OP1G363C, YCpGAL1-hTOP1K720E, YCpGAL-1hTOP1A653 P), which prove resistant to camptothecin. A number of mutations are present close to the active site of the enzyme (tyrosine 723) and others around position 363 which corresponds to a very well conserved region. Before effecting the transformation of the yeasts, the yeasts were unfrozen and plated with a sterile bent glass rod in 90-mm plates containing sterile solid YPDa medium (10 g of yeast extract, 20 g of peptone, 20 g of dextrose, 0.7 g of adenine, 20 g of glucose, 20 g of agar per liter). Colonies formed after 48-72 hours in an incubator at 30° C. One day before the transformation, a single yeast colony sample was taken with a sterile Gilson tip and inoculated in 5 ml of sterile liquid YPDA medium (the above-mentioned medium without agar). The colony was grown overnight under stirring at 30° C. On the day after, 5 ml of the saturated culture were diluted in sterile liquid YPDA medium and grown at 30° C. up to an optical density of 1.0 at 600 nm. The cells were centrifuged for 5 min at 4000× g, at room temperature and the precipitate was resuspended in 25 ml of a (T/E) solution containing Tris-EDTA (TE) 10 mM pH 7.5, EDTA 1 mM and lithium acetate 100 mM. The yeast suspension was centrifuged for 5 min at 4000× g at room temperature. The precipitate was resuspended in the same previous fresh solution (approximately 500 μl), so as to have 2×10 9 cells/ml. To accomplish the transformation, 200 μg of carrier DNA, 1 μg of plasmid DNA and 200 μl of competent cells were placed in an Eppendorf spectrophotometer. 1.2 ml of a TE/lithium acetate solution containing PEG 40% were added and the yeast suspension was stirred for 30 min at 30° C. A thermal shock was generated by placing the yeast suspension at 42° C. for 15 min and then plating it in selective plates, i.e. uracil-free plates containing complete minimal medium (CM) (1.3 g of dropout powder containing various amino acids but lacking uracil, 1.7 g of yeast nitrogen base without amino acids and ammonium sulphate, 5 g of ammonium sulphate, 20 g of glucose and 20 g of agar per liter). The plates were incubated at 30° C. until transformation. Before treating the yeasts with the camptothecin derivatives (in-vivo spot test), the transformed colonies were inoculated with a Gilson tip in 5 ml sterile liquid CM medium. The colonies were grown overnight under stirring at 30° C. On the day after, the optical density of the colonies was measured at 600 nm and a dilution of the colonies was performed in order to obtain an optical density of 0.3. From this first dilution 10-fold serial dilutions were obtained (1:10, 1:100, 1:1000) in 96-well plates. Five μl of each dilution were pipetted onto 90-mm plates containing solid CM medium. For the controls 2% glucose and 2% galactose were added, whereas for the dilutions treated with the camptothecin derivatives 2% galactose and the products at the 45 μM concentration were added. The colonies were incubated at 30° C. for 48-72 hours and analysed macroscopically. The effect of the camptothecin derivatives ST2544 and ST2598 was evaluated. Topoisomerase I wild-type DNA presented a phenotype of sensitivity to ST2544 and ST2598, whereas the mutated enzymes G363C and A653P proved resistant to the derivatives tested. The K720E mutant, however, presented a phenotype of sensitivity to the ST2544 derivative. The results are presented in the following table. TABLE 2 Growth of Saccharomyces cerevisiae yeast in the presence of camptothecin derivatives in vivo Drug TOP1 G363C K720E A653P DMSO ++++ ++++ ++++ ++++ ST2544 −−−− ++++ +−−− ++++ ST2598 −−−− ++++ ++++ ++++ From left to right each symbol denotes the growth of the 4 serial yeast dilutions. + Viability of Saccharomyces cerevisiae yeast; − Lethality of Saccharomyces cerevisiae yeast. Effect of ST2544 Against MKN-28 Human Gastric Carcinoma Tumor fragments were inoculated on both flanks at day 0. Treatment started when tumors were just palpable. The molecule was given by oral route and intravenously according to the schedule q4d×4. During the treatment, animals were inspected every day for mortality. Physical appearance, behavior and general and local clinical signs of the mice will be observed daily. Any deviation from normality was recorded. All animals were weighed during the whole treatment period, in order to calculate the percent body weight loss due to the treatment. Tumor volume inhibition % in treated over control tumors was evaluated 20 days after last treatment. To determine the antitumor activity of the drug, tumor diameters was measured biweekly with a Vernier caliper. The formula TV (mm 3 )=[length (mm)×width (mm) 2 ]/2 was used, where the width and the length are the shortest and the longest diameters of each tumor, respectively. When tumors reached a weight of about 2 g, the mice were sacrificed by cervical dislocation. LCK (log cell kill) as index of efficacy was calculated to evaluate the persistence of the effect of the molecule at the end of the treatment. The results are reported in table 3. TABLE 3 Antitumor activity of ST2544 (q4dx4) p.o. or i.v. in athymic nude mice bearing s.c. the MKN-28 human gastric carcinoma Dose LCK Drug (mg/kg) TVI % (1000 mm 3 ) BWL % Tox ST2544 iv 1 34 0.2 1 0/4 iv 2 36 0.2 6 0/4 iv 4 66 0.8 0 0/4 ST2544 p.o. 1 28 0.1 5 0/4 p.o. 2 62 0.5 1 0/4 p.o. 4 72 1 7 0/4 When ST2544 was delivered by oral route showed to significantly inhibit the tumor growth at 4 and 2 mg/kg (q4d×4), since IVI was >50%, whereas when it was given intravenously was efficacious at 4 mg/kg (q4d×4) (TVI=66%). The persistence of the effect on tumor growth measured at the end of the treatment was observed after oral administration at 4 mg/kg (LCK=1).

4y

FIELD OF THE INVENTION [0001] This invention relates generally to methods and apparatus for making very precise, reliable and reproducible measurements of concentrations of organic, inorganic and total carbon present in aqueous samples. Such methods and apparatus may be used, for example, to determine the concentration of total organic carbon (TOC) in drinking water, raw water, wastewater, industrial process streams and the like. Such measurement may be utilized for various important commercial purposes, for example to optimize water purification processes, to detect spills, and to monitor compliance with environmental regulations. The methods and apparatus of this invention can generally be applied both to measuring discrete aqueous samples, such as those encountered in a laboratory environment, and to monitoring flowing streams to provide real-time concentration data. [0002] The apparatus of this invention is able to rapidly and accurately measure carbon in samples containing high concentrations of salts and particulate material because the sample is oxidized at high temperatures and pressures, but is cooled to near ambient temperature before the sample exits the reactor. Since at least a portion of the sample leaves the reactor in the liquid phase, salts and particulate material are swept from the reactor and do not accumulate there. The conditions of the oxidation result in efficient oxidation and accurate carbon measurements that cannot be achieved in oxidations initiated by UV radiation or in wet chemical oxidation at lower temperatures. Furthermore, samples that are highly contaminated, especially with particulate material, are uniquely handled in the apparatus so that they do not cause excessive wear of sample syringes, valves, or other components, and do not settle out in the fluidic components. By maintaining the particulate material suspended in the liquid sample, plugging of fluidic components by particulates is minimized, and any organic material in those particulates is measured accurately. BACKGROUND OF THE INVENTION [0003] A. Overview [0004] Total organic carbon is a well-established water quality parameter that quantifies the overall concentration of organic substances, all of which are typically regarded as contaminants, in an aqueous environment. Total organic carbon in an aqueous sample may be composed of either one or two components—dissolved organic carbon (DOC) and particulate organic carbon. The measurement of DOC is conventionally accomplished by filtering the water sample, commonly through a 0.45-μm filter, to remove particulate organic carbon prior to performing an analysis for DOC. The limitations of conventional apparatus and techniques for such analysis often lead to the result that only DOC is effectively measured, instead of TOC, because the particulates in a sample containing both forms of organic carbon typically cause errors in the measurement and plug fluid passages causing hardware failures. [0005] In the following description, ‘DOC’ is used to refer to measurements in which the sample has first been filtered to remove particulates, while ‘TOC’ is used herein to refer to measurements in which the sample has not been filtered. In other respects, however, the following description is relevant to both DOC and TOC measurements. [0006] In one known approach DOC and/or TOC, the organic compounds in an aqueous sample are oxidized to carbon dioxide (CO 2 ) and the CO 2 in the sample is then measured. In addition to organic carbon components, the water sample may initially contain CO 2 and other inorganic forms of carbon (e.g., in the form of bicarbonate and carbonate salts). Together, these forms of inorganic carbon are referred to herein as IC. Total carbon (TC) concentration in an aqueous sample is therefore the sum of the TOC and IC concentrations. [0007] Because an aqueous sample following an oxidation step could contain CO 2 originating from both IC and TOC sources, the IC must be accounted for in some way to accurately measure TOC. One way to deal with IC is to remove the IC from the sample before the sample is oxidized. This is commonly done by acidifying the sample to convert carbonates and bicarbonates into free CO 2 , and then sparging it with CO 2 -free gas to remove that CO 2 originating from IC sources. It has been found, however, that at least some volatile organic compounds may be removed from the sample during such a sparging step. Thus, when the sparged sample is subsequently oxidized, the CO 2 produced is from the oxidation of the remaining (non-purgeable) organics in the sample, so this measurement is often referred to as the measurement of non-purgeable organic carbon (NPOC). Since many samples contain few, if any, purgeable organic compounds, the concentration of NPOC in those samples is typically considered to be essentially equal to the TOC concentration. [0008] A second way of dealing with IC in a sample is to separately measure the TC and IC concentrations. When using this approach, the TOC concentration is calculated from the concentration difference, TC minus IC (TC−IC). One advantage of this approach is that the sample is not sparged so that purgeable organics are not lost thereby eliminating this source of measurement errors. As a result, the measurement of TOC by this “difference” approach is potentially more accurate. [0009] When the approach to measuring carbon concentrations in aqueous samples is not constrained by requirements for regulatory compliance, a technician usually selects the parameter to be measured based on the time and resources required for each measurement, and the expected composition of the samples being monitored. Often, NPOC measurements are performed because they are relatively fast. Where it is necessary to accommodate a variable IC concentration, or where loss of purgeable organic carbon results in too large a discrepancy to be tolerated, TOC (or DOC) is measured by the difference approach, as described above. [0010] In other cases, the samples may either contain IC concentrations that are known to be small compared to the TOC concentration, or the IC concentrations are relatively constant. In such cases, a technician may elect to measure TC because it is fast and it provides a sufficiently accurate indication of TOC trends for many common applications. [0011] B. Identification of Related Prior Art [0012] The following U.S. patents, each of which is incorporated herein by reference, are representative of pertinent prior art patents in the field of this invention and in related technical areas, such as oxidation of organic wastes: U.S. Pat. No. 3,296,435 (Teal '435); U.S. Pat. No. 3,700,891 (Luft '891); U.S. Pat. No. 3,958,945 (Takahashi '945); U.S. Pat. No. 4,619,902 (Bernard '902); U.S. Pat. No. 4,882,098 (Weetman '098); U.S. Pat. No. 4,896,971 (Weetman '971); U.S. Pat. No. 4,902,896 (Fertig '896); U.S. Pat. No. 5,037,067 (Ray '067); U.S. Pat. No. 5,232,604 (Swallow '604); U.S. Pat. No. 5,271,900 (Morita '900); U.S. Pat. No. 5,482,077 (Serafin '077); U.S. Pat. No. 5,630,444 (Callaghan '444); U.S. Pat. No. 5,835,216 (Koskinen '216); U.S. Pat. No. 6,007,777 (Purcell '777); U.S. Pat. No. 6,114,700 (Blades '700); U.S. Pat. No. 6,142,458 (Howk '458); U.S. Pat. No. 6,375,900 B1 (Lee-Alvarez '900); and U.S. Pat. No. 6,988,825 B2 (Colville '825). [0013] The following technical publications, which are also incorporated herein by reference, are also representative of the pertinent prior art in this field: Aiken, G. R., “Chloride Interference in the Analysis of Dissolved Organic Carbon by the Wet Oxidation Method,” Environ. Sci. Technol., Vol. 26, No. 12, pp. 2435-2439; 1992; le Clercq, M.; van der Plicht, J. and Meijer, H. A. J., “A Supercritical Oxidation System for the Determination of Carbon Isotope Ratios in Marine Dissolved Organic Carbon,” Analyt. Chim. Acta, Vol. 370(1), pp. 19-27; 1998; Eyerer, P., “TOC Measurements on the Basis of Supercritical Water Oxidation,” AE-2e.1; Fraunhover-Gesellschaft zur Foerderung, Institut Chemische Technologie; Munich, Germany, http://www.ict.fraunhofer.de/english/projects/meas/onlan/index.htm#a5; ISO-CEN EN 1484, “Water Analysis Guidelines for the Determination of Total Organic Carbon (TOC) and Dissolved Organic Carbon (DOC),” 1997; Koprivnjak, J-F, et al., “The Underestimation of Concentrations of Dissolved Organic Carbon in Freshwaters,” Water Research, Vol. 29, No. 1, pp. 91-94, 1995; Menzel, D. W. and Vaccaro, R. F., “The Measurement of Dissolved Organic and Particulate Carbon in Seawater,” Limnology and Oceanography, Vol. 9(1), pp. 138-142, 1964; Nitta, M.; Iwata, T.; Sanui, Y. and Ogawachi, T., “Determination of Total Organic Carbon in Highly Purified Water by Wet Oxidation at High Temperature and High Pressure,” presented at Tenth Annual Semiconductor Pure Water Conference; Feb. 26-28, 1991, Santa Clara, Calif.; in Conference Proceedings, Balazs, M. K. (Ed.), pp. 314-320; Wangersky, P. J., “Dissolved Organic Carbon Methods: A Critical Review,” Marine Chem., Vol. 41, pp. 61-74, 1993; and, William, P. J. leB. et al., “DOC Subgroup Report,” Marine Chem., Vol. 41, pp. 11-21, 1993. These patents and technical publications are further referred to in the following description. [0014] C. Prior Art Related to Sample Handling and Sparging [0015] Many prior art analyzers, such as those described in Morita '900, Purcell '777 and Lee-Alvarez '900, draw the sample into a syringe pump. Those syringe pumps use rotary valves to connect the syringe to the sample, reagents, dilution water and other analyzer apparatus. Any salts and particulates in the sample contact the sealing surfaces of the valve and syringe. As particles settle onto those surfaces, they cause wear and premature leaking. Salts also dry on the surfaces and cause additional wear because the salt crystals are abrasive. [0016] Efficient sparging has been a goal of certain of the prior art patents and publications. Takahashi '945, for example, describes a multi-stage sparger for use in TOC analyzers. Employing more than one stage improves the efficiency of the sparging process. However, the large internal volume of this device would make it difficult to flush out between uses with different samples that have widely different concentrations of contaminants. [0017] Weetman '098, Weetman '971, and Howk '458 teach that sparging can be made more efficient by stirring the solution with rotating propellers. This modified sparging method would be complex to incorporate in an analytical instrument, however, because of the motor and rotating seals that would be required. [0018] In some prior carbon analyzers that add reagents to the sample, mixing is facilitated by bubbling gas through the solution (for example, Purcell '777). As discussed above, however, some samples should be measured without sparging because sparging can remove volatile organics and thereby introduce an error into the measurements. However, no analyzer is known to incorporate a device that can be used to sparge certain samples when desired, while also mixing other samples with reagents without sparging. Further, in prior analyzers, when the sparging stops, any particulates in the solution settle to the bottom of the sparger. This makes it impossible to accurately measure organic material in the particles, and it increases the likelihood that fluid passages of the apparatus will become plugged. [0019] D. Prior Art Related to Oxidation Techniques [0020] It is well known in the art to oxidize organic carbon using wet chemical methods. For example, in the Menzel and Vacarro publication, the authors report measuring DOC and particulate organic carbon in seawater by oxidizing a 5 mL sample in a sealed glass ampoule that also contained the oxidizing agent potassium persulfate. The oxidation was achieved by heating the ampoule to 130° C. for 30 min. After the heating step, the ampoule was cooled, broken open, and the CO 2 contained inside it was measured using a non-dispersive infrared (NDIR) detector. Among other disadvantages, this method has the disadvantage that it involves many manual steps. Furthermore, the ampoules can break when they are heated or handled, raising concerns about loss of data and safety. This method would be impractical for real-time monitoring of process streams, or even laboratory analyses where many samples are to be analyzed each day. [0021] Bernard '902 describes an instrument that automates the wet chemical oxidation method. The sample is acidified and a persulfate-containing reagent is added prior to the oxidation. CO 2 -free gas is bubbled through the sample to remove the IC (in preparation for making an NPOC measurement) or to transfer it to a NDIR detector for measurement of the IC. The solution is then heated to 90 to 100° C. at ambient pressure to achieve oxidation of the organics. During the oxidation, the CO 2 is transferred to the NDIR detector where it is measured. The oxidation by persulfate at these temperatures is slow; in fact, the innovative aspect of Bernard '902 is the use of metal catalysts to increase the rate of the oxidation. [0022] Another shortcoming of such wet chemical methods is that the oxidation of organics by prior wet chemical methods is incomplete, especially when the sample contains chloride [as reported for example in the publications of William, et al.; Wangersky; Koprivnjak, et al.; and Aiken]. When the oxidation is incomplete, the TOC measurement is inaccurate because not all of the organic carbon is measured. [0023] Purcell '777 describes another analytical instrument that measures carbon in aqueous samples. In this case, the sample is acidified and an oxidizing reagent (a solution containing persulfate salts) is added to the sample. This mixing occurs in a syringe, and the resulting solution is then transferred to a sparger. After sparging, the syringe transfers the sample to a reactor where the solution is irradiated with ultraviolet (UV) radiation. In the presence of the UV radiation and the persulfate reagent, many organics in the sample are oxidized to CO 2 , and the CO 2 is measured in a NDIR detector. [0024] A problem with the oxidation of organics using UV radiation, as in Purcell '777, is that it is inefficient when the sample contains particulates. For example, one study reported that TOC analyzers that are based on UV oxidation detected less than 3% of the cellulose particles added to samples at an actual concentration of 20 mg C/L. By comparison, analyzers based on high-temperature catalytic oxidation (HTCO), as described below, on average detected 83.2% of the cellulose represented by cellulose particles. [0025] To achieve more complete oxidation and, therefore, greater accuracy, analyzers were developed that oxidize organics using HTCO. Teal '435, for example, teaches that TOC in aqueous samples can be measured by injecting a portion of an IC-free sample into a catalytic reactor heated to around 900° C. The water vaporizes immediately, and organic materials are oxidized to CO 2 upon contact with the catalyst. A carrier gas (oxygen) transports the CO 2 out of the reactor to a NDIR detector. [0026] Morita '900 and Lee-Alvarez '900 describe methods and apparatus that automatically acidify and sparge samples, oxidize organics using HTCO, and use NDIR detectors to measure the CO 2 . In both of these approaches, the sample is mixed with acid in a syringe connected to a multi-port valve that directs fluids to other components. Morita '900 describes the sparging as being performed inside the syringe, while Lee-Alvarez '900 describes a separate sparger. [0027] A shortcoming of all methods based on HTCO is that samples containing salts or particulate material will eventually plug the reactor because the water evaporates in the reactor, leaving nonvolatile salts and particulates behind. In addition, the reactor typically requires two hours or more to cool enough so that it can be safely removed and cleaned. Then, about another two hours are required for the reactor to heat back up to its operating temperature. This means that the instrument is out of service for an extended period whenever the reactor must be cleaned. [0028] Other oxidation methods have also been reported. The Nitta et al. technical publication describes an analyzer in which the sample is mixed with sulfuric acid and sodium persulfate. IC is removed by sparging, and then a pump pressurizes a continuously flowing stream of the solution to 2.0 to 2.5 MPa (284 to 356 psig). The pressurized solution is heated in a reactor to 200° C., and the organics are oxidized to CO 2 . The solution then flows through a flow restrictor (it is the flow through this restrictor that generates the upstream pressure as stated above). The CO 2 produced during the oxidation is removed by sparging and is measured using an infrared detector. Several Japanese patents describe additional aspects of the instrument as described above (JP63135858, JP1021352, JP1021355, JP1021356, JP1021356, JP1049957, JP1049958, JP1318954, JP1318955, JP1318956, and JP5080022). This method has the advantage that higher oxidation temperatures, presumably with more complete oxidation, can be achieved than if the oxidation were performed at ambient pressure. However, the apparatus has the disadvantage that particles and salts will rapidly plug the restrictor. Furthermore, the cost of such an apparatus is likely to be high because solution has to be pumped continuously against the backpressure generated by the restrictor. [0029] Attempts to improve the efficiency of the oxidation also have included oxidizing samples under supercritical conditions (i.e., above 374° C. and pressures above 22.12 MPa). Le Clercq et al. reported measuring carbon isotope ratios in DOC. Between 500 and 1,000 mL of seawater were mixed with oxygen, pumped to a maximum pressure of 35 MPa, and forced through an alumina reactor heated to 650° C. Placing a 0.18 mm ID capillary downstream of the reactor and setting the flow rate at 2 mL/min produced the aforementioned pressure. The gases exiting the capillary were cooled to collect the CO 2 formed during the oxidation, and a mass spectrometer was used to measure the isotopes of carbon in the CO 2 . A problem with this apparatus is that samples that contain particulates tend to plug the capillary. Such a problem was reported by le Clercq et al., and they installed a 2-μm filter ahead of the capillary in an attempt to mitigate the problem. However, in applications in which the apparatus must operate for long periods, even the periodic plugging of such a filter would create excessive maintenance and downtime. Another problem is the extremely high temperature and pressure at which the oxidation is made to occur. Appropriate hardware for such operating conditions is costly, and it is likely to corrode rapidly. The reactor described in this technical literature was made from alumina to minimize corrosion, but the structural characteristics of alumina make it unreliable. For this reason, the alumina reactor had to be mounted inside a metal shield for safety. [0030] Eyerer reported another approach. The sample is first pumped through an electrochemical cell that generates the oxidizing agent. Then the sample passes through a reactor heated up to 600° C. and through a valve that creates a backpressure up to 26 MPa. The sample is oxidized at those conditions and then passes over a hydrophobic membrane. Some of the CO 2 diffuses through the membrane and is measured in a mass spectrometer. This apparatus suffers from the same types of corrosion, reliability, and cost shortcomings, however, that were discussed above for the le Clercq et al. approach. [0031] Beyond applications in the measurement of organic carbon, as described above, rapid oxidation also has been a goal of developers of organic waste destruction systems. One way of achieving the desired rapid oxidation rates has been to perform the oxidation at near-critical and supercritical conditions. A variety of oxidizing agents have been employed, and one of the most economically attractive oxidizers is the oxygen in air. Swallow '604 teaches that if ozone, hydrogen peroxide, or salts containing persulfate, permanganate, nitrate, and other oxygen-containing anions are added to the liquid/air mixture, the oxidation rate is sufficiently rapid that the exothermic process operates without supplemental heating. This is an important consideration for large industrial processes, but it is much less important to analytical instrumentation because the hardware is much smaller. [0032] Instead of oxidizing organics in a continuously flowing stream, batches of the sample could be heated. To do that requires that the batch be sealed in a container that is subsequently heated, and the best way of automatically sealing the container would be to use a valve that can withstand the pressure generated during heating. Many valves designed for high-pressure applications employ precision sealing surfaces. Ball valves require highly polished balls in packing glands to avoid leaks. Other high-pressure valves require metal-to-metal seals (for example, as described in Callaghan '444). Those valves are costly and subject to rapid wear by particles in the liquid. [0033] A better method of achieving valve sealing in the presence of particulates is to use a softer seal that is resistant to abrasion. Serafin '077 teaches that elastomeric seals can be used in check valves at high pressure, and Ray '067 describes the use of O-rings to seal the ports in a plug valve. Both inventions have the disadvantage that the seals are not easily accessed for replacement when they become worn. [0034] E. Prior Art Related to NDIR Detectors [0035] NDIR detectors of CO 2 used as components of TOC analyzers commonly use a rotating chopper wheel to modulate the infrared (IR) radiation, and a pneumatic IR detector to measure the IR radiation that has not been absorbed by the CO 2 being measured. Luft '891 describes such a NDIR detector. Shortcomings of this technology include the fact that the chopper wheel mechanism is subject to failure, and irregularities in the size and orientation of the openings in the chopper wheel produce significant electrical noise in the measurement of CO 2 . [0036] To overcome the effects of temperature and pressure on NDIR response, detectors with built-in temperature and pressure compensation have been reported, such as in Fertig '896. An alternative approach to overcoming temperature effects is to use an IR detector that is relatively unaffected by temperature, such as a pyroelectric detector. Koskinen '216 describes a NDIR detector that electronically modulates the IR source to avoid problems with chopper wheels, and it uses a pyroelectric IR detector. However, this NDIR uses a costly Fabry-Perot interferometer to select the IR wavelength that is measured. [0037] Blades '700 describes a NDIR detector designed specifically for use in a TOC analyzer. The IR source is an electrically modulated incandescent lamp with a pyroelectric IR detector. However, the use of an incandescent lamp limits the dynamic range and sensitivity of the NDIR because the modulation is limited to low frequencies. [0038] Commonly, NDIR detectors use rectifier circuits and lowpass filters to produce a DC signal that is proportional to the average output of the IR detector. Shortcomings of this technology include the conversion of “noise” over a wide bandwidth into a part of the rectifier output signal. Additionally, the lowpass filter that averages the rectified waveform also impairs the ability of the NDIR to respond to rapidly changing CO 2 concentrations. Blades '700 reports an NDIR that uses two synchronous detectors, with each responding to opposite half-cycles of the signal from the IR detector. The use of two synchronous detectors improves the response time limitation of the rectifier circuit, but this approach still suffers from the shortcoming of mixing noise into the output signal. [0039] Carbon measurement instruments commonly generate chlorine when the sample contains chloride ions. That chlorine would corrode many NDIR detectors, so scrubbers are used to remove the chlorine before it enters the NDIR (as, for example, in Lee-Alvarez '900 and Purcell '777). The scrubber is a consumable that adds to the operating cost and maintenance labor of those instruments. [0040] These and other limitations of, and deficiencies in, the prior art approaches to IC, TOC and TC measurements are overcome in whole, or at least in part, by the methods and apparatus of this invention. OBJECTS OF THE INVENTION [0041] Accordingly, a general object of this invention is to provide methods and apparatus for determining the presence of and/or measuring one or more other elements, other than hydrogen and oxygen, e.g., an impurity, that may be present in an aqueous sample when at least one of such other elements may be present in organic form, inorganic form or both. [0042] A more particular object of the present invention is to provide methods and related apparatus, which may be readily automated, for determining the presence of and/or measuring organic and/or inorganic carbon in one or a series of discrete aqueous samples. [0043] Another principal object of the present invention is to provide methods and related automated apparatus for measuring and/or monitoring the concentrations of organic and/or inorganic carbon in one or more flowing aqueous streams. [0044] Another object of this invention is to provide methods and related apparatus for measuring organic and inorganic carbon in one or a series of discrete aqueous samples and/or flowing streams that may contain particulates and salts. [0045] Yet another object of this invention is to provide for the addition of reagents and, when needed, dilution water to a sample being tested in a way that particulates and salts in the sample do not plug fluid passages or cause excessive wear to syringe pump components. [0046] Still another object of this invention is to provide for the effective transfer of particulates in an aqueous sample being analyzed into a sealable oxidation reactor in a substantially homogenous solution or suspension, so that carbon concentration measurements accurately reflect the amount of carbon in the particulate material. [0047] Another object of this invention is to provide methods and related apparatus for oxidizing, reacting and/or decomposing organic material in an aqueous sample using a reactor that can be sealed while an aqueous sample inside the reactor is subjected to temperature and pressure conditions sufficient to cause oxidation, reaction and/or decomposition of the organic material in the sample. [0048] A more specific object of this invention is to provide methods and related apparatus that oxidize the organic carbon in an aqueous sample substantially completely in a sealable reactor, so that the measurements of organic carbon accurately reflect all of the carbon whether present in dissolved and/or particulate form in the sample. [0049] Yet another object of this invention is to provide methods and related apparatus that measure CO 2 derived from the organic and/or inorganic carbon in an aqueous sample in a way that is reliable, reproducible and essentially unaffected by variations in temperature, pressure, or concentrations of CO 2 in the ambient air. [0050] Another object of this invention is to measure CO 2 derived from the organic and/or inorganic carbon in an aqueous sample over a wide range of concentrations, while rejecting “noise” or interferences that would limit CO 2 measurement accuracy at low concentrations and yet still responding quickly to rapid changes in the CO 2 concentration. [0051] Still another object of this invention is to measure CO 2 derived from the organic and/or inorganic carbon in an aqueous sample while substantially avoiding corrosion of the measurement apparatus by chlorine or other oxidation products emanating from an oxidation reactor used in the measurement method. [0052] These and other objects and advantages of this invention will be apparent from the following detailed description with reference to the attached drawings. SUMMARY OF THE INVENTION [0053] By contrast with the limitations of the prior art approaches to making such carbon concentration determinations in aqueous samples, as discussed above, the methods and apparatus of the present invention are uniquely capable of measuring all of the aforementioned parameters in samples that contain concentrations of TOC, dissolved solids, and particulates. In general a sample is drawn into the analyzer of this invention, reagents are added, and the sample is diluted as necessary. With the present invention, it is possible to completely avoid having the sample enter apparatus components that would be damaged by the dissolved solids or particulates in the sample. This invention also keeps the particulates suspended in the sample solution at least until it enters the oxidation reactor. This procedure therefore allows particulate organic carbon to be measured accurately, and it avoids additional maintenance labor and downtime that would otherwise be caused if particulates were allowed to settle out in the sparger and plug sample passages. [0054] The oxidation of the organic carbon (or other organic material) in a known volume of sample processed according to this invention occurs in a reactor, which can alternately be sealed to contain a fluid therein at elevated temperature and pressure conditions or unsealed to introduce or remove a fluid sample. Such a sealable reactor is uniquely designed and adapted to be capable of handling samples that contain salts and particulates. In a representative invention embodiment, a known volume of sample is flowed into the sealable reactor, which initially is cool, through an open reactor inlet port. The reactor is then sealed and, after being sealed, is rapidly heated to temperature and pressure conditions at which the organic material in the sample is rapidly oxidized. Because the water in the aqueous sample cannot boil away in the sealed interior of the reactor, the sample (and the organic material in the sample) can be heated to relatively high temperatures and pressures. Furthermore, it has been found that, at the high temperature/pressure conditions attainable inside the sealed reactor of this invention, water in the aqueous sample can become a supercritical fluid that exhibits special properties including properties that facilitate the rapid oxidation of organic material. [0055] When the oxidation of organic material is complete, the reactor is quickly cooled to near ambient temperature so as to condense a liquid reactor product. The reactor is then opened, and the oxidized sample exits the reactor through an open reactor outlet port in part as a liquid reactor product (taking with it the salts that were originally dissolved in it) together with a gaseous reactor product that will include organic material oxidation products such as CO 2 . Particulates also are flushed out of the reactor. Because a liquid reactor product is recovered in this step, the salts and particulates do not accumulate in the reactor, and, as a result, maintenance and downtime are minimized. [0056] The CO 2 in an oxidized sample coming from the reactor is measured in an innovative type of NDIR detector according to this invention that is reliable, stable, and has a wide dynamic range. These characteristics of the NDIR detector of this invention allow the analyzer to operate for long periods without recalibration. [0057] The present invention has a particular advantage in that samples are not drawn into a syringe or its valving, where salts and particulates would cause leaks. Instead, the sample and the reagents are drawn into a length of tubing by means of a syringe that itself contains only clean dilution water. That dilution water also can be used to dilute samples that contain very high concentrations of organic carbon prior to further processing. In a preferred embodiment of this invention, the analyzer is capable of measuring up to about 1,000 ppm TOC in a sample without dilution of the sample, and up to about 50,000 ppm TOC in a sample if the sample is diluted (the only constraint here being the preferred sizes of the various apparatus components, with a larger apparatus being capable of handling even higher TOC concentrations with appropriate dilution). [0058] The mixture or combination of sample and reagents (and dilution water when necessary) then enter a mixing device according to this invention that can both mix and sparge the solution/suspension. The mixing apparatus consists of a solenoid and a magnetic stirrer (stirring bar) that is coated with an inert polymer to prevent corrosion. The stirring bar may have protrusions on each end that help to agitate the sample mixture as the bar moves up and down in the chamber. This design requires no motors or rotating seals. The magnetic mixer of this invention has been found to unexpectedly improve the efficiency of the sparging when it is activated. Such an improvement is unexpected in view of the fact that the gas bubbles by themselves seem to agitate the solution vigorously during the sparging process. Less time is therefore required for essentially complete removal of IC when using the mixing/sparging apparatus of this invention, thus making the analysis faster. [0059] Organic compounds are oxidized efficiently in a preferred embodiment of this invention at temperatures around 375° C. At this temperature, the oxidation of organics with persulfate, oxygen, or other oxidizers is rapid and substantially complete. We have found that there is no corrosion of the reactor and valves when they are constructed from titanium. [0060] The reactor in the present invention is unusually reliable because it is heated only during the short period when a sample is actually being oxidized. The preferred reactor of this invention has a relatively small mass which allows it to be rapidly heated to oxidize the sample, and then rapidly be cooled back down to ambient temperature. The present invention can be put into service rapidly upon initial startup or after maintenance, thereby minimizing downtime. [0061] In a preferred embodiment of the invention, the special high-pressure valves used at the inlet and outlet ports of the reactor tube include seals constructed of high-density polyethylene, polyvinylidene fluoride (PVDF), or elastomers such as ethylene propylene diene monomer (EPDM). The use of these materials allows the valves to seal reliably even when the sample being processed contains particulate material, and the cost of these valves is reduced because precision machining is not necessary. An unusual feature of the reactor valves according to this invention is that the seals can be easily and quickly replaced when they do become worn. In addition, the reactor valves of this invention are unlike any other known valves because each valve incorporates a bypass fluid path that allows the interior of each of the valves to be flushed clean when the reactor is sealed. [0062] The present invention does not require costly high-pressure pumps or restrictors that would be plugged by particulates. It does not require the use of fragile ampoules, UV lamps that contain toxic mercury, or expensive catalysts. The completeness of oxidation is not degraded by the presence of chloride or particulate materials in the sample. Unlike HTCO reactors of the prior art, the present invention does not accumulate salts or particulates in the reactor, and maintenance on the reactor is minimal. [0063] The NDIR detector according to the present invention is especially reliable because it has no moving parts, and it is constructed of materials that are compatible with oxidation products coming from the reactor, including chlorine. Unlike many other comparable instruments, with this invention no scrubbers are required to remove chlorine from the gas entering the NDIR. [0064] The IR source utilized in this invention can be selected from among various types of infrared radiation sources, including incandescent light bulbs, thermal radiators, and electroluminescent diodes. The IR source in the preferred embodiment is a thin thermoresistive film that produces intense IR radiation, even when electrically modulated at high frequencies that permit low concentrations of CO 2 to be measured with precision. [0065] The IR detector utilized in this invention can also be selected from among various types of infrared radiation detectors, including bolometric, thermoelectric, and photoelectric types. The pyroelectric IR detector in a preferred invention embodiment is one that is relatively immune to temperature changes. To further eliminate the effects of temperature, the IR source and IR detector may be controlled at fixed temperatures in a preferred embodiment. The IR source and IR detector are preferably mounted in chambers that are flushed with CO 2 -free gas, thereby preventing response variations due to changes in the ambient CO 2 concentration. The response of the NDIR may also be adjusted to compensate for changes in the pressure of the CO 2 . [0066] Multiple wavelengths can be used to measure CO 2 in the NDIR of this invention, and the selected wavelength can be implemented in any of several ways, including the use of optical filters and the use of IR sources that emit radiation of the desired wavelengths (e.g., light-emitting diodes). When optical filters are used, they can be located in various locations within the NDIR detector. In a preferred embodiment, a nominal wavelength of about 4.26 μm is used for CO 2 measurement, and the optical filter that is employed to eliminate other wavelengths is part of the IR detector, and typically is located immediately in front of its sensing element. [0067] In one illustrative embodiment of this invention, a sample is drawn into the instrument using a syringe pump. Instead of the sample entering the syringe, however, the sample enters a length of tubing that can be easily and inexpensively replaced if it ever becomes plugged or permanently contaminated by a sample. The tubing is advantageously coiled to reduce the amount of space it occupies inside the instrument. [0068] The syringe is also arranged and/or connected so as to sequentially (but in any desired order) draw acid and oxidizer reagents and sample into the coil of tubing if the concentration of the organic carbon in the sample is very large, dilution water can be drawn in, too, as discussed above. The total volume of liquid drawn into the tubing is known by monitoring the operation of the syringe pump, so dilution ratios can be controlled precisely. [0069] The several fluids in the coil tubing can then be discharged to a mixing location in the apparatus, such as a chamber that combines a mixer and sparger. The sample and other fluids in the mixing chamber can be thoroughly mixed and sparged to measure NPOC, or mixed without sparging when TC or IC is being measured. The mixing action keeps particulates suspended substantially homogenously in solution or suspension, so the solution/suspension can be accurately measured without plugging the mixing chamber or the tubing connected to it. [0070] A portion of the sample mixture from the mixing chamber is then flowed to a reactor tube of an oxidization reactor where it is sealed in an interior region of the reactor tube. Reactor valves as described above, and able to withstand high pressures, seal each end of the reactor tube. The tube is then heated to temperatures between about 150° C. and 650° C., or preferably between about 300° C. and 400° C., and more preferably between about 350° C. and 390° C. The tube is heated for approximately one to thirty minutes, e.g., preferably for about two to four minutes. At the end of that period, the heater is turned off, and a fan blows ambient air over the reactor tube to rapidly cool it to near ambient temperature. The valves are opened, and a CO 2 -free carrier gas is used to blow the reactor liquid and reactor gas from the interior region of the reactor tube. The liquid and gas reactor products are separated, and the carrier gas transfers the gaseous oxidation products, including the CO 2 , to a chemical detector, e.g., an NDIR detector, in accordance with this invention for carbon measurement. [0071] In the NDIR, IR radiation is emitted from an IR source that is electrically modulated at a suitable frequency, in one preferred invention embodiment at 55 Hz. In one preferred embodiment, the IR source is maintained at a suitable fixed temperature (e.g., about 65° C.) in a chamber that is purged by CO 2 -free gas. The IR radiation from the source is collimated by a lens and passes through the gas (a combination of the gaseous oxidation products and carrier gas) flowing from the reactor. Any CO 2 present in the gas flowing through the NDIR absorbs IR at wavelengths around 4.26 μm, e.g., 4.26 μm±0.2 μm. The IR radiation that is not absorbed by CO 2 then passes through a second lens that focuses it onto an IR detector. In one preferred embodiment, a filter is located on the face of this IR detector to block IR at wavelengths other than 4.26 μm from reaching the pyroelectric detector element, and the IR detector is mounted in a chamber that is purged with CO 2 -free gas, and is maintained at a fixed temperature (e.g., about 55° C.). [0072] The NDIR electronic circuitry drives the IR source at the modulation frequency, and the IR detector converts the infrared light that it receives back into an electrical signal, which signal is attenuated by any CO 2 present in the gas being measured. The NDIR electronic circuitry conditions this signal with a bandpass filter, and then converts this analog signal to digital with an analog-to-digital converter that samples the waveform many times per modulation cycle (in one preferred invention embodiment, at 100 waveform samples per modulation cycle). The NDIR electronic circuitry also uses digital signal processing techniques to perform further bandpass filtering and to measure the amplitude of the received signal. From this amplitude, the NDIR electronic circuitry calculates and reports the CO 2 concentration in the gas flowed from the reactor. [0073] In a more specific apparatus embodiment, this invention comprises an analytical instrument for measuring carbon in a liquid sample, wherein the instrument comprises in combination: a sample inlet; a pump to draw said sample and, optionally, other materials into the apparatus; a mixing chamber; a source of sparging and/or carrier gas and a gas flow control system; an oxidation reactor, wherein the oxidation reactor can be sealed at each end to contain a sample mixture; a heater; a fluid pumping system to transport liquids and mixtures of gases and liquids through the aforementioned components; and a CO 2 detector to measure CO 2 in the reactor product coming from the reactor. [0074] In another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes an acidic reagent inlet. [0075] In another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes an oxidizer reagent inlet. [0076] In another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes a dilution water inlet. [0077] In still another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes a fan or blower to cool the reactor. [0078] In still another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes a mixing or mixing/sparging chamber that is configured in a way that relatively easily permits a sparging gas to be bubbled through a solution or liquid suspension contained in the mixing/sparging chamber. [0079] In yet another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes a valve or comparable flow control element for directing or channeling gas coming from the mixing/sparging chamber (after it has been bubbled through a solution or liquid suspension, e.g., an acidified sample mixture, contained in the chamber) to the CO 2 detector. [0080] In another specific embodiment, this invention comprises an analytical instrument having the several elements and components as described above, and further includes a NDIR detector designed to measure a wide range of CO 2 concentrations using AC signal processing for noise rejection/filtering and for signal amplitude measurements. [0081] In another specific embodiment, this invention comprises automating an analytical instrument having the several elements and components as described above using electronic and/or computer control systems as herein described. [0082] In another specific embodiment, this invention comprises methods of operating and controlling an analytical instrument having the several elements and components as described above. [0083] In a general method embodiment, a method according to this invention comprises the sequential steps of: drawing a selected volume of sample into a sample-handling portion of the analytical system; adding suitable volumes of an acid reagent (of a known acidity or acid concentration) and, depending on the type of carbon being measured, also of an oxidizer reagent (of a known concentration) relative to the volume of sample; possibly diluting the sample/acid/oxidizer mixture with low or essentially zero TOC dilution water if desired; mixing the sample, acid, oxidizer (if present) and dilution water (if any) to form a substantially homogenous solution or liquid suspension; if NPOC is to be measured, sparging the acidified solution/suspension with CO 2 -free gas (provided, for example, by a gas control assembly of the system) while controlling the flow rate of the sparge gas to ensure that IC in the sample is substantially completely removed; alternatively, if TC or IC is to be measured, mixing but not sparging the solution/suspension; transferring a portion of the homogenous mixed/sparged solution/suspension to an oxidation reactor; if NPOC or TC is to be measured, heating the portion of the solution/suspension after the reactor is sealed to oxidize organic compounds in the portion of the solution/suspension, then cooling it to near room temperature; using a stream of carrier gas from a gas control assembly to transfer the liquid and gaseous reactor products in the reactor to a gas/liquid separator; separating the liquid from the gas, and removing the separated liquid from the gas/liquid separator; flowing the gaseous reactor product (containing the CO 2 ) from the gas/liquid separator to an NDIR detector; measuring the CO 2 in the gaseous reactor product using the NDIR detector; and, optionally, after the CO 2 in the gaseous reactor product is measured, flowing the gaseous reactor product back through the gas/liquid separator and then venting it to the atmosphere. [0084] In another apparatus embodiment, an apparatus according to this invention comprises the following apparatus elements or components in combination: a sample-handling unit comprising multiple valves and a syringe connected through a three-way valve to both a coil of tubing and a reservoir containing low-TOC dilution water, wherein the internal volume of the coil of tubing is larger than the internal volume of the syringe; a pump to draw sample from a sample source and deliver it by a conduit connection to a six-way fluid interconnection element; a mixing/sparging chamber connected to the coil of tubing, said chamber including a sparging element for sparging CO 2 -free gas through a solution/suspension in the chamber; a source of compressed CO 2 -free gas connected to the sparging element and a gas control module to control the flow and pressure of such gas; optionally, a valve and conduit to direct gas emerging from the mixing/sparging chamber through a gas/liquid separator and then to an NDIR detector; a pump and associated conduit to transfer at least a portion of the mixed/sparged solution/suspension from the mixing/sparging chamber to a sealable reactor; a source of carrier gas connected to the reactor and, via the gas/liquid separator, to an in-line filter and then to the NDIR detector; a heater and a fan associated with the reactor; and an associated automated control system comprising electrical connections and operational software adapted to operate fluid valves and other system control elements according to a predetermined sequence and/or timing or, alternatively, in accordance with feedback received from various system monitors. [0085] In another specific apparatus embodiment, an NDIR detector in accordance with this invention comprises three chambers: a first chamber containing an IR source; a second chamber centrally located and comprising an optical path through which carrier gas and a gaseous reactor product including CO 2 flow; and a third chamber containing the IR detector, wherein said first and third chambers are designed to be flushed with a CO 2 -free gas during measurements. [0086] In another specific apparatus embodiment, a mixer/sparger element in accordance with this invention comprises a top section that includes a liquid inlet and a sparge gas outlet, a bottom section that includes an inlet port for sparge gas and a liquid outlet, and a middle section containing a magnetic stirrer component, the middle section being located inside a solenoid coil which can be activated by passing a series of current pulses through it causing the magnetic stirrer component to move up and down inside the middle section. [0087] In another specific apparatus embodiment, an apparatus in accordance with this invention comprises a pair of high-pressure reactor valves, each such valve comprising a polymeric or elastic seal attached to a plunger that moves back and forth inside a valve body when an associated motor is activated, and wherein the rear portion of the seal retains two O-rings so as to seal the interior of the housing, and wherein the front portion of that seal plugs a reactor opening (a reactor inlet or a reactor outlet) when the valve is in a closed position. [0088] In another specific apparatus embodiment, an IR source for the NDIR in accordance with this invention comprises a modulated, thin-film IR radiator. In another specific apparatus embodiment, an NDIR detector in accordance with this invention comprises a pyroelectric sensor element, with the preferred embodiment having a pyroelectric sensor constructed from lithium tantalate. [0089] Even more specifically, the present invention comprises the following embodiments: [0090] 1. An analytical instrument comprising in combination: a liquid sample inlet; a fluid transport system for drawing a known volume of a liquid sample into the instrument and for transporting liquids and gases to and through the components of the instrument; a reactor that can alternately be opened, to introduce a sample or to discharge a reactor product, or sealed to heat treat a sample inside the reactor to produce a reactor product; a reactor heating unit that can be turned on during a reactor heating cycle and turned off during a reactor cooling cycle; a reactor cooling unit that can be turned on during a reactor cooling cycle and turned off during a reactor heating cycle; a source of gas and a gas flow control system in communication with the fluid transport system; and, a chemical detector to measure a chemical component of the reactor product. [0091] 2. The instrument of paragraph 1 further comprising a fluid pumping system in communication with the fluid transport system. [0092] 3. The instrument of paragraph 1 further comprising one or more additional inlets selected from an acid reagent inlet, an oxidizer reagent inlet and a dilution water inlet. [0093] 4. The instrument of paragraph 1 further comprising a mixing/sparging chamber upstream from the reactor where a combination of a liquid sample and one or more other liquids can be either mixed or mixed and simultaneously sparged with sparge gas. [0094] 5. The instrument of paragraph 1 wherein the chemical detector comprises a detector for carbon, nitrogen or sulfur oxidation products downstream of the reactor. [0095] 6. The instrument of paragraph 1 wherein the chemical detector comprises a non-dispersive infrared (NDIR) detector downstream of the reactor. [0096] 7. The instrument of paragraph 6 wherein the NDIR includes an optical filter specific to the wavelength of IR radiation absorbed by the chemical component to be measured. [0097] 8. The instrument of paragraph 7 wherein the optical filter is specific to carbon oxidation products. [0098] 9. The instrument of paragraph 7 wherein the optical filter is specific to CO 2 . [0099] 10. The instrument of paragraph 6 further comprising a gas/liquid separator between the reactor and the NDIR detector to remove liquid from the reactor product. [0100] 11. The instrument of paragraph 1 further comprising an AC signal processing element effective for noise rejection/filtering and signal amplitude measurements. [0101] 12. The instrument of paragraph 1 further comprising an electronic/computer automated control system. [0102] 13. An analytical instrument comprising: a sample-handling unit comprising multiple valves and a syringe connected through a three-way valve to both a coil of tubing and a reservoir containing low-TOC dilution water, wherein the volume of the coil is at least as large as the volume of the syringe; a pump component effective to draw sample from a sample source and deliver it by a conduit connection to a fluid interconnection element; a mixing/sparging chamber connected to the coil of tubing, said chamber including a sparging element for sparging CO 2 -free gas through a solution/suspension in the chamber; a source of compressed CO 2 -free gas connected to the sparging element and a gas control module to control the flow and pressure of such gas; a pump component and associated conduit to transfer at least a portion of the solution/suspension from the mixing/sparging chamber to a sealable reactor; a heater and a fan associated with the reactor; a source of carrier gas connected to the reactor; a conduit downstream of the reactor carrying the reactor product sequentially through a gas/liquid separator, an in-line filter, and then to a CO 2 detector; and an associated automated control system comprising electrical connections and operational software adapted to operate fluid valves and other system control elements according to a predetermined sequence and/or timing or, alternatively, in accordance with feedback received from various system monitors. [0103] 14. The instrument of paragraph 13 further comprising a valve and a conduit for carrying sparge gas emerging from the mixing/sparging chamber through the gas/liquid separator to the CO 2 detector. [0104] 15. An analytical method comprising the following sequential steps: drawing a known volume of sample into a sample-handling portion of an analytical system; adding suitable volumes of one or more chemical reagents relative to the volume of sample; mixing the sample and chemical reagents to form a substantially homogenous solution or suspension; transferring a portion of the homogenous solution/suspension to a reactor; sealing the reactor; treating the solution/suspension in the sealed reactor to form a reactor product; bringing the reactor and the reactor products to about ambient temperature; opening the reactor and, using a stream of carrier gas, transferring the liquid and gaseous reactor products from the reactor to a gas/liquid separator; separating the liquid reactor product from the gaseous reactor product; flowing the gaseous reactor product from the gas/liquid separator to a chemical detector; and, measuring a chemical component in the gaseous reactor product using the detector. [0105] 16. The method of paragraph 15 wherein the chemical reagents are selected from acid and oxidizer. [0106] 17. The method of paragraph 15 further including the step of adding dilution water to the sample and chemical reagents. [0107] 18. The method of paragraph 15 wherein the step of mixing the sample and chemical reagents also includes simultaneously sparging the solution/suspension with a sparge gas. [0108] 19. The method of paragraph 18 further comprising the step of monitoring the progress of the sparging step by flowing the sparge gas from the mixing/sparging step to the chemical detector for analysis. [0109] 20. The method of paragraph 15 wherein the solution/suspension includes organic materials and is heated in the reactor to a temperature between about 150° C. to about 650° C. in the reactor step substantially to oxidize the organic materials. [0110] 21. The method of paragraph 15 wherein the solution/suspension is heated to supercritical fluid temperature/pressure conditions in the reactor step. [0111] 22. The method of paragraph 15 wherein the solution/suspension is heated to a temperature of about 100° C. or less in the reactor step. [0112] 23. The method of paragraph 15 wherein the chemical detector is specific to a material selected from carbon, nitrogen and sulfur oxidation products. [0113] 24. The method of paragraph 15 wherein the chemical detector is a CO 2 detector. [0114] 25. The method of paragraph 15 wherein the chemical detector is a non-dispersive infrared (NDIR) detector. [0115] 26. The method of paragraph 25 wherein the NDIR includes an optical filter specific to the wavelength of IR radiation absorbed by the chemical component to be measured. [0116] 27. The method of paragraph 26 wherein the optical filter is specific to [0117] CO 2 . [0118] 28. The method of paragraph 15 further wherein an AC signal processing element is used for noise rejection/filtering and signal amplitude measurements. [0119] 29. The method of paragraph 15 further wherein the analysis is automated by an electronic/computer automation control system. [0120] 30. The method of paragraph 15 further comprising the step of determining a concentration of a chemical component in the sample using a mathematical formula to correlate a response of the chemical detector to the gaseous reactor product with the concentration of the chemical component. [0121] 31. Apparatus for treating an aqueous sample containing organic material comprising: (a) a reactor having reactor inlet and outlet ports and a reactor interior for containing an aqueous sample under above-ambient temperature and pressure conditions; (b) high-pressure fluid reactor valve members at said reactor inlet and outlet ports, said reactor valve members allowing fluid flow respectively into or out of the reactor interior when in an open-valve mode or, alternatively, sealing the reactor interior when in a closed-valve mode; (c) a reactor heater system adapted for rapidly and cyclically heating the reactor interior to above-ambient temperature conditions where an aqueous sample is sealed in the reactor interior; and, (d) a reactor cooling system adapted for rapidly and cyclically cooling the reactor interior and an aqueous sample sealed in the reactor interior following a heating cycle. [0126] 32. The apparatus of paragraph 31 wherein the reactor heating system is able to heat the reactor interior and an aqueous sample sealed in the reactor interior to a temperature of about 150° C. to about 650° C., while the reactor interior and the reactor valve members maintain the sample under sealed conditions. [0127] 33. The apparatus of paragraph 31 wherein the reactor heating system is able to heat the reactor interior and an aqueous sample sealed in the reactor interior to temperature and pressure high enough to generate supercritical fluid conditions inside the reactor interior, while the reactor interior and the reactor valve members maintain the sample under sealed conditions. [0128] 34. The apparatus of paragraph 31 wherein each of the reactor valve members comprises a valve housing having a main fluid inlet and a main fluid outlet, a moveable valve plunger element inside the valve housing, a front portion of the valve plunger element comprising a polymeric or elastic plunger seal member having a section sized and shaped to mate with and plug the main fluid outlet when the valve plunger element is in an advanced position, and to unseal the main fluid outlet when the valve plunger element is in a retracted position. [0129] 35. The apparatus of paragraph 34, the valve member further comprising a motor for alternately advancing or retracting the valve plunger element. [0130] 36. The apparatus of paragraph 34, the valve housing further comprising a purge gas inlet and a purge gas outlet whereby a purge gas can be flowed through the interior of the valve housing while the valve plunger element is sealing the main fluid outlet. [0131] 37. The apparatus of paragraph 31 wherein the reactor heater system comprises a hollow tubular heating element with the reactor in the hollow interior of the heating element. [0132] 38. The apparatus of paragraph 31 wherein the reactor cooling system comprises a fan located proximate to the reactor and oriented to blow ambient air along the exterior of the reactor. [0133] 39. The apparatus of paragraph 37 wherein the tubular heating element is open at each end, and further wherein the reactor cooling system comprises a fan located proximate to one open end of the heating element and oriented to blow ambient air through the hollow interior of the heating element and along the exterior of the reactor. [0134] 40. Apparatus for mixing an aqueous sample containing particulate material with one or more other liquid components, said apparatus comprising: (a) a sealed tubular mixing container having a liquid inlet/gas outlet section at a first container end, said liquid inlet/gas outlet section including a sample inlet and a sparge gas outlet; a liquid outlet/gas inlet section at a second container end, said liquid outlet/gas inlet section including a sparge gas inlet and a sample outlet; and, between said liquid inlet/gas outlet section and said liquid outlet/gas inlet section, a fluid mixing region; (b) a magnetically activatable stirrer element inside said fluid mixing region; (c) an annular solenoid coil surrounding at least a portion of said fluid mixing region, said solenoid coil being activatable by a series of electric current pulses to move the stirrer element inside the fluid mixing region; and, (d) a porous gas disperser located between the sparge gas inlet and the fluid mixing region. [0139] 41. The apparatus of paragraph 40 wherein the stirrer element is coated with a corrosion-resistant outer layer. [0140] 42. The apparatus of paragraph 40 wherein the gas disperser has gas pores with a pore size ranging from about 1 μm to about 0.125 in. [0141] 43. The apparatus of paragraph 40 wherein the stirrer element is activatable independently of whether sparge gas is being supplied to the fluid mixing region. [0142] 44. A purgeable fluid sealing valve apparatus comprising: (a) a valve housing having a main fluid inlet and a main fluid outlet; (b) a moveable plunger element inside the valve housing, a front portion of the valve plunger element comprising a plunger seal member sized and shaped to be seated on and plug the main fluid outlet when the valve plunger element is in an advanced position, and to unseal the main fluid outlet when the plunger is in a retracted position; and, (c) the valve housing further comprising a valve purge gas inlet and a valve purge gas outlet whereby a purge gas can be flowed through the interior of the valve housing while the valve plunger element is sealing the main fluid outlet. [0146] 45. The fluid sealing valve apparatus of paragraph 44 wherein said plunger seal member comprises a polymeric or elastic member. [0147] 46. The fluid sealing valve apparatus of paragraph 44 further wherein an exterior wall of the valve plunger element is adapted to seat one or more O-ring seals. [0148] 47. The fluid sealing valve apparatus of paragraph 44 further comprising a conduit connection from a source of purge gas to the valve purge gas inlet. [0149] 48. The fluid sealing valve apparatus of paragraph 44 further comprising a motor for alternately advancing or retracting the valve plunger element. 49. A purgeable non-dispersive infrared (NDIR) detector apparatus comprising: (a) an IR source chamber comprising an IR source chamber purge gas inlet and a purge gas outlet, and containing an infrared radiation source; (b) an IR detector chamber comprising an IR detector chamber purge gas inlet and a purge gas outlet, and containing an infrared detector; and, (c) between the IR source chamber and the IR detector chamber, an optical path chamber having an optical chamber gas inlet port at a first end of the optical path chamber and an optical chamber gas outlet port at a second end of the optical path chamber. [0153] 50. The NDIR apparatus of paragraph 49 further comprising a first compartment separation lens that isolates the IR source chamber from the optical path chamber, and a second compartment separation lens that isolates the IR detector chamber from the optical path chamber. [0154] 51. The NDIR apparatus of paragraph 49 further comprising an optical filter mounted in the infrared detector in front of the sensing element of the detector. [0155] 52. The NDIR apparatus of paragraph 51 wherein the optical filter is a 4.26 μm±0.2 μm filter. [0156] 53. The NDIR apparatus of paragraph 49 further comprising an electronic control system for automating operation of the apparatus, comprising: (a) a driver to actuate the IR source at the modulation frequency; (b) a bandpass filter to pass the infrared detector signal content at the modulation frequency; (c) an analog-to-digital converter to sample the output of the bandpass filter many times during each modulation cycle; and, (d) digital signal processing elements to further bandpass filter the samples from the analog-to-digital converter, and to calculate the amplitude of the resulting AC signal. [0161] 54. The NDIR apparatus of paragraph 49 further comprising an electronic control system for automating operation of the apparatus. [0162] 55. The NDIR apparatus of paragraph 49 further comprising conduit connections from a source of purge gas to the IR source chamber purge gas inlet and to the IR detector chamber purge gas inlet. [0163] 56. The NDIR apparatus of paragraph 49 wherein the IR source comprises a modulated, thin-film IR radiator. [0164] 57. The NDIR apparatus of paragraph wherein the IR detector comprises a pyroelectric, lithium tantalate sensor element. [0165] 58. A sample/reagent handling apparatus comprising: (a) separate sources of one or more liquids selected from an aqueous solution/suspension containing at least an impurity, dilution water, oxidizing reagent, and acid; (b) conduit connections between the sources of the aqueous solution/suspension, oxidizing reagent and acid and a first end of a length of holding tubing, and a dilution water conduit connection between the dilution water source and a second end of the tubing; (c) a calibrated syringe in fluid communication with the dilution water conduit connection, the syringe having an internal volume that is equal to or less than the internal volume of the tubing; (d) a conduit connection between the first end of the tubing and a mixing device; and, (e) fluid valves along each of the conduit connections such that the syringe can be used to separately draw measured volumes of oxidizing reagent, acid and aqueous solution/suspension into the first end of the tubing by drawing dilution water from the second end of the tubing into the syringe, followed by discharging the dilution water in the syringe back into the second end of the tubing in order to transfer the liquids held in the first end of the tubing to the mixing device. [0171] 59. The sample/reagent handling apparatus of paragraph 58 further comprising a multi-way fluid hub located along the conduit connections between the aqueous solution/suspension, oxidizing reagent and acid sources and the first end of the tubing. [0172] 60. The sample/reagent handling apparatus of paragraph 58 wherein the mixing device comprises a mixing chamber in which the liquids transferred from the first end of the tubing can be mixed, or sparged with sparge gas, or mixed and sparged simultaneously. [0173] 61. The sample/reagent handling apparatus of paragraph 60 wherein the mixing device comprises: (a) a sealed tubular mixing container having a liquid inlet/gas outlet section at a first container end, said liquid inlet/gas outlet section including a sample/reagent inlet and a sparge gas outlet; a liquid outlet/gas inlet section at a second container end, said liquid outlet/gas inlet section including a sparge gas inlet and a sample mixture outlet; and, between said liquid inlet/gas outlet section and said liquid outlet/gas inlet section, a fluid mixing region; (b) a magnetically activatable stirrer element inside said fluid mixing region; (c) an annular solenoid coil surrounding at least a portion of said fluid mixing region, said solenoid coil being activatable by a series of electric current pulses to move the stirrer element inside the fluid mixing region; and, (d) a porous gas disperser located between the sparge gas inlet and the fluid mixing region. [0178] 62. Liquid treatment apparatus for treating an aqueous sample containing a non-aqueous component to prepare the sample for a measurement of the non-aqueous component, said apparatus comprising a sample/reagent handling apparatus according to paragraph 61 in combination with a reactor apparatus comprising: (a) a reactor having reactor inlet and outlet ports and a reactor interior for containing an aqueous sample under above-ambient temperature and pressure conditions; (b) high-pressure fluid reactor valve members at said reactor inlet and outlet ports, said reactor valve members allowing fluid flow respectively into or out of the reactor interior when in an open-valve mode or, alternatively, sealing the reactor interior when in a closed-valve mode; (c) a reactor heater system adapted for rapidly and cyclically heating the reactor interior to above-ambient temperature conditions where an aqueous sample is sealed in the reactor interior; (d) a reactor cooling system adapted for rapidly and cyclically cooling the reactor interior and an aqueous sample sealed in the reactor interior following a heating cycle; and, (e) a mixing device/reactor conduit connection between the sample mixture outlet of said mixing device and the fluid reactor valve member at said reactor inlet port. [0184] 63. Analytical apparatus for measuring a non-aqueous component of an aqueous sample wherein at least a portion of the non-aqueous component may be present in the form of an organic material, said apparatus comprising a liquid treatment apparatus according to paragraph 62 in combination with a non-dispersive infrared (NDIR) detector apparatus comprising: (a) an IR source chamber comprising an IR source chamber purge gas inlet and a purge gas outlet, and containing an infrared radiation source; (b) an IR detector chamber comprising an IR detector chamber purge gas inlet and a purge gas outlet, and containing an infrared detector; (c) between the IR source chamber and the IR detector chamber, an optical path chamber having an optical chamber gas inlet port at a first end of the optical path chamber and an optical chamber gas outlet port at a second end of the optical path chamber; and, (d) a reactor/NDIR conduit connection between the fluid reactor valve member at said reactor outlet port and the optical chamber gas inlet port of the NDIR detector. [0189] 64. The analytical apparatus of paragraph 63 further comprising a gas/liquid separator along the reactor/NDIR conduit connection to remove liquid components of the product of the reactor prior to reaching the NDIR. [0190] 65. The analytical apparatus of paragraph 63 further comprising a gas supply system that provides CO 2 -free carrier gas to the reactor to transport reactor gas products along the reactor/NDIR conduit to the NDIR. [0191] 66. The analytical apparatus of paragraph 65 wherein each of the fluid reactor valve members comprise: (a) a valve housing having a main fluid inlet and a main fluid outlet; (b) a moveable plunger element inside the valve housing, a front portion of the valve plunger element comprising a plunger seal member sized and shaped to be seated on and plug the main fluid outlet when the valve plunger element is in an advanced position, and to unseal the main fluid outlet when the plunger is in a retracted position; and, (c) the valve housing further comprising a valve purge gas inlet and a valve purge gas outlet whereby a purge gas can be flowed through the interior of the valve housing while the valve plunger element is sealing the main fluid outlet; and, further wherein there is a conduit connection from the gas supply system to the valve purge gas inlet. [0195] 67. The analytical apparatus of paragraph 66 wherein there are conduit connections between the gas supply system and the IR source chamber purge gas inlet and the IR detector chamber purge gas inlet. [0196] 68. A method for treating an aqueous sample containing organic material, the method comprising the steps of: (a) mixing a known volume of the aqueous sample with one or more other liquids selected from oxidizer, acid and dilution water to form a sample mixture; (b) flowing at least a portion of the sample mixture into the interior of a reaction vessel which is at substantially ambient conditions, said reactor vessel being adapted to be alternately and repeatedly opened and sealed at reactor inlet and outlet ports; (c) sealing the portion of sample mixture in the interior of the reaction vessel; (d) rapidly heating the interior of the reaction vessel and the sample mixture portion inside to temperature and pressure substantially above ambient conditions and for a time sufficient substantially to oxidize the organic material and form a reactor product; (e) stopping the heating step and then rapidly cooling the interior of the reaction vessel and the reactor product inside to substantially ambient conditions to form cooled liquid and gaseous reactor products; and, (f) opening the reaction vessel and removing the cooled liquid and gaseous reactor products from the reactor interior. [0203] 69. The method of paragraph 68 wherein the reactor interior is heated to a temperature between about 150° C. to about 650° C. in step (d). [0204] 70. The method of paragraph 68 wherein the reactor interior is heated to temperature and pressure high enough to generate supercritical fluid conditions in step (d). [0205] 71. The method of paragraph 68 wherein the reactor interior is heated to a temperature of about 100° C. or less in step (d). [0206] 72. The method of paragraph 68 wherein the reaction vessel is positioned in the hollow interior of a tubular heating element which is turned on to effect the heating step (d). [0207] 73. The method of paragraph 68 wherein the heating step (d) is completed in about 30 minutes or less. [0208] 74. The method of paragraph 68 wherein the heating step (d) is completed in about 4 minutes or less [0209] 75. The method of paragraph 68 wherein the reaction vessel is cooled in cooling step (e) by blowing ambient air over the exterior of the reaction vessel. [0210] 76. The method of paragraph 68 wherein the reaction vessel is sealed in step (c) by closing purgeable high-pressure reactor valves at the reactor inlet and outlet ports, the method additionally comprising the step of flowing a CO 2 -free purge gas through the respective interiors of the reactor valves while the reaction vessel is sealed. [0211] 77. The method of paragraph 68 further comprising the step of flowing CO 2 -free carrier gas through the interior of the reaction vessel as a part of step (f). [0212] 78. A method for treating the combination of an aqueous sample containing particulate material and one or more other liquid components to form a substantially homogeneous and, optionally, gas-free liquid mixture, the method comprising the steps of: (a) introducing the aqueous sample containing particulate material and the other liquid components into a mixing chamber having a liquid inlet and outlet, a gas inlet and outlet, and containing a magnetically activated stirring member; (b) activating the stirring member to move inside the mixing chamber and to agitate the liquid contents and form a sample mixture; and, (c) if the removal of gases from the sample mixture is desired, introducing a substantially CO 2 -free sparge gas to a lower portion of the mixing chamber simultaneously with activation of the stirring member. [0216] 79. The method of paragraph 78 wherein the other liquid components are selected from oxidizing reagent, acid and diluting water. [0217] 80. The method of paragraph 78 wherein the stirring member is activated by passing a series of current pulses through an annularly disposed solenoid coil surrounding the mixing chamber. [0218] 81. The method of paragraph 78 wherein the sparge gas is introduced into the mixing chamber through a porous gas disperser. [0219] 82. The method of paragraph 81 wherein the porous gas disperser has pores with a pore diameter of about 1 μm to 0.125 in. [0220] 83. The method of paragraph 79 wherein step (c) is carried out for a period of about 10 seconds to 20 minutes at a sparge gas flow rate of about 50 to 500 cc/min. [0221] 84. A method for measuring a chemical component of a fluid stream comprising the steps of: (a) providing a non-dispersive infrared (NDIR) detector apparatus comprising: (i) a sealed IR source chamber comprising an IR source chamber purge gas inlet and a purge gas outlet, and containing an infrared radiation source; (ii) a sealed IR detector chamber comprising an IR detector chamber purge gas inlet and a purge gas outlet, and containing an infrared detector; and, (iii) between the IR source chamber and the IR detector chamber, a sealed optical path chamber having an optical chamber fluid inlet port at a first end of the optical path chamber and an optical chamber fluid outlet port at a second end of the optical path chamber; (b) flowing a fluid stream containing the chemical component into the inlet port, through the optical chamber, and out through the outlet port, while IR radiation is being directed through the optical chamber; (c) throughout step (b), flowing a purge gas that is substantially free of the chemical component being measured through the IR source chamber and the IR detector chamber; (d) modulating the intensity of the IR radiation directed through the optical chamber; and, (e) based on the detection response of the chemical detector to the passage of the fluid stream through the optical chamber, calculating a concentration of the chemical component using a mathematical correlation formula. [0230] 85. The method of paragraph 84 wherein the NDIR includes an optical filter that filters IR radiation at wavelengths other than the wavelength that is absorbed by the chemical component. [0231] 86. The method of paragraph 85 wherein the chemical component is CO 2 and the optical filter is a 4.26 μm±0.2 μm optical filter. [0232] 87. The method of paragraph 84 wherein step (e) is based either on a determination of peak absorbance of the IR radiation by the chemical component in the fluid stream flowing through the optical chamber or by determining the area of the complete response curve generated by passing the fluid stream through the optical chamber. [0233] 88. The method of paragraph 84 further comprising the steps of automating the NDIR detection and measurement sequence with an electronic/computer control system comprising: (a) a driver to actuate the IR source at the modulation frequency; (b) a bandpass filter to pass the infrared detector signal content at the modulation frequency, while rejecting DC offset, noise, and harmonics of the modulation frequency; (c) an analog-to-digital converter to sample the output of the bandpass filter many times during each modulation cycle; and, (d) digital signal processing elements to further bandpass filter the samples from the analog-to-digital converter to reject noise while passing the signal at the modulation frequency, and to calculate the amplitude of the resulting AC signal. [0238] 89. The method of paragraph 84 further comprising the steps of automating the NDIR detection and measurement sequence with an electronic/computer control system. [0239] 90. A method for introducing measured volumes of an aqueous sample and one or more other liquids into an analytical instrument using a single measurement syringe without contaminating the syringe with the sample or the other liquids, said method comprising the steps of (a) providing a sample/reagent handling system comprising: (i) separate sources of one or more liquids selected from an aqueous solution/suspension, dilution water, and one or more reagents; (ii) conduit connections between the sources of the aqueous solution/suspension and the reagents and a first end of a length of holding tubing, and a dilution water conduit connection between the dilution water source and a second end of the tubing; (iii) a calibrated syringe in fluid communication with the dilution water conduit connection, the syringe having an internal volume that is less than or equal to the internal volume of the tubing; and, (iv) fluid valves along each of the conduit connections; (b) filling the holding tubing with dilution water; (c) drawing a first measured volume of a first one of the aqueous sample or the other liquids into the first end of the tubing by opening and/or closing the appropriate fluid valves and then opening the syringe to draw the first measured volume of dilution water into the syringe from the second end of the tubing; (d) drawing a second measured volume of a second one of the aqueous sample or the other liquids into the first end of the tubing by opening and/or closing the appropriate fluid valves and then additionally opening the syringe to draw the second measured volume of dilution water into the syringe from the second end of the tubing; and, (e) transferring the first measured volume of the first one of the liquids and the second measured volume of the second one of the liquids to a mixing location by opening and/or closing the appropriate fluid valves and then closing the syringe to fully discharge all of the dilution water in the syringe back into the second end of the tubing thereby driving the liquids in the first end of the tubing out of the tubing. [0249] 91. The method of paragraph 90 further comprising the step between steps (d) and (e) of drawing a third measured volume of a third one of the aqueous sample or the other liquids into the first end of the tubing by opening and /or closing the appropriate fluid valves and then additionally opening the syringe to draw the third measured volume of dilution water into the syringe from the second end of the tubing. [0250] 92. The method of paragraph 90 wherein the holding tubing is coiled to occupy a smaller space. [0251] 93. The method of paragraph 90 further wherein the sample/reagent handling system includes a multi-way fluid hub located along the conduit connections between the liquid sources and the first end of the tubing. [0252] 94. An analytical method comprising the steps of: (a) introducing measured volumes of an aqueous sample and one or more other liquids into an analytical apparatus according to the method of paragraph 90; (b) transferring the measured volumes of liquids from the first end of the holding tube to a mixing location where the liquids are thoroughly mixed and, optionally, can also be sparged to form a sample mixture; (c) flowing at least a portion of the sample mixture to a sealable reaction vessel, and treating the sample mixture by the steps of: (i) sealing the portion of sample mixture in the interior of the reaction vessel; (ii) rapidly heating the interior of the reaction vessel and the sample mixture portion inside to temperature and pressure substantially above ambient conditions and for a time sufficient substantially to oxidize the organic material and form a reactor product; (iii) stopping the heating step and then rapidly cooling the interior of the reaction vessel and the reactor product inside to substantially ambient conditions to form cooled liquid and gaseous reactor products; and, (iv) opening the reaction vessel and removing the cooled liquid and gaseous reactor products from the reactor interior; and, (d) transferring at least the gaseous reactor product to a chemical detector and measuring a chemical component of the gaseous reactor product using the detector. [0261] 95. The method of paragraph 94 further including the step of treating the reactor product in a gas/liquid separator to remove the liquid reactor product before sending the gaseous reactor product to the chemical detector. [0262] 96. The method of paragraph 94 further wherein the chemical detector is a non-dispersive infrared (NDIR) detector. [0263] These and other specific method and apparatus embodiments of this invention will be better understood in connection with the following detailed invention description and the several drawings in which: BRIEF DESCRIPTION OF THE DRAWINGS [0264] FIG. 1 (Block Diagram) is a diagram showing in block form the five key fluidic sub-assemblies of a preferred embodiment of a measurement apparatus according to this invention. [0265] FIG. 2 (Fluidics Schematic) is an overall schematic of the functional components of a measurement apparatus according to this invention showing in detail the several component elements that comprise each of the several fluidic sub-assemblies as illustrated in FIG. 1 . [0266] FIG. 3 (Sparger With Mixing Function) is a schematic, partially cut-away/sectional view of a mixer/sparger component in accordance with this invention. [0267] FIG. 4 (High-Pressure Valve) is a schematic, partially cut-away/sectional view of a high-pressure reactor valve used to seal the reactor in accordance with this invention. [0268] FIG. 5 (Reactor Assembly) is a schematic, partially cut-away/sectional view of a reactor sub-assembly in accordance with this invention. [0269] FIG. 6 (NDIR Optical Bench) is a schematic, partially cut-away/sectional view of an NDIR sub-assembly in accordance with this invention. [0270] FIG. 7 (Block Diagram of NDIR Detector) is a block diagram illustrating internal details and related electrical connections and components of an NDIR sub-assembly as illustrated in FIG. 6 . [0271] FIG. 8 (Response to CO 2 ) is a graph illustrating a typical response of a NDIR detector in accordance with this invention to CO 2 contained in a gaseous reactor product produced in the instrument by oxidation of organic compounds. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0272] FIG. 1 is a block schematic of one preferred embodiment of an automated carbon measurement apparatus/analyzer according to this invention illustrating the five component sub-assemblies 1 to 5 that comprise the analyzer. As illustrated in FIG. 1 , an aqueous sample is drawn into a sample-handling sub-assembly 1 of the apparatus, where the desired volumes of acid reagent and/or oxidizer reagent are added to a selected volume of sample. The sample may also be diluted at this stage with low-TOC dilution water if necessary before being passed to reactor sub-assembly 3 . [0273] The sample, reagents and dilution water if any are mixed in the sample-handling portions of the apparatus to create a sample mixture comprising a substantially homogenous solution or suspension. If NPOC is to be measured, the acidified sample mixture also is sparged with CO 2 -free gas provided by the gas control sub-assembly/module 2 . The flow rate of the sparge gas is controlled to ensure that IC in the sample is removed efficiently and substantially completely. If TC or IC is to be measured, the sample mixture is mixed but not sparged. [0274] A portion of the homogenous solution/suspension is then transferred to the reactor sub-assembly 3 . If NPOC or TC is to be measured, the solution/suspension containing oxidizer is heated in a sealed reactor to oxidize the organic compounds in the solution/suspension, and then it is cooled to near room temperature. If IC is to be measured, oxidizer is not added to the solution/suspension. In this case, the solution/suspension may be warmed to facilitate conversion of bicarbonates and carbonates to CO 2 , but it is not heated so much that oxidation of organic compounds occurs. [0275] Next, a stream of carrier gas from the gas control assembly/module 2 transfers the liquid and gas products in the reactor sub-assembly 3 to a gas/liquid separator sub-assembly/module 4 . The liquid exits the analyzer from the gas/liquid separator module 4 while the gas product, containing the CO 2 , flows to the NDIR detector sub-assembly 5 . After the CO 2 in the gas product is measured, the gas product and carrier gas mixture can be flowed through the gas/liquid separator module 4 , and vented to the atmosphere. [0276] FIG. 2 is a schematic showing the several fluidic components of the apparatus in more detail. In FIG. 2 , sub-assemblies 1 to 5 as shown in FIG. 1 are delineated by broken lines. The sample-handling sub-assembly 1 comprises a syringe 6 that is connected through a three-way valve 7 to a coil of tubing 8 and a dilution water reservoir 9 containing low-TOC dilution water. A representative practice of the invention using the apparatus as illustrated in FIG. 2 is described below. It will be understood, however, that alternative sequences and methods for introducing the sample, reagent(s) and dilution water into the system could be used consistent with the scope of this invention. For example, using the apparatus illustrated in FIG. 2 , the oxidizer and acid reagents could be moved from coil 8 to a mixing location in the apparatus, such as to mixer/sparger 18 , prior to introducing the sample into the system in order to maintain a separation between these components until they are ready to be mixed at the mixing location. [0277] Initially, the syringe is empty, and the valve 7 and coil 8 contain only dilution water. The volume of coil 8 is designed and selected to be at least as large as, and preferably larger than, the volume of syringe 6 , so the only liquid that can enter the syringe is dilution water from coil 8 or reservoir 9 . When an analysis begins, valve 10 is open, and valves 11 , 12 , and 13 are closed. Syringe 6 starts filling with dilution water drawn from a syringe end of coil 8 , which causes oxidizer reagent from oxidizer reagent reservoir 14 to be drawn through the six-way fluid element 17 and into a sample/reagent end of coil 8 . When syringe 6 has drawn the required volume of oxidizer into the sample/reagent end of coil 8 , syringe 6 stops momentarily and valve 10 closes. Valve 11 opens and syringe 6 draws additional dilution water from the syringe end of coil 8 into syringe 6 , which in turn draws the required volume of acid from acid reservoir 15 into the sample/reagent end of coil 8 , where it may partially mix with the oxidizer reagent already in this end of coil 8 . When the desired volume of acid has entered coil 8 , the syringe 6 stops momentarily, valve 11 closes, and valve 12 opens to allow the required volume of sample to be drawn into the sample/reagent end of coil 8 , as additional dilution water from the syringe end of coil 8 is drawn into syringe 6 . When the required volume of sample has entered the coil, syringe 6 stops again, and valve 12 closes. The coil 8 now contains the desired volumes of oxidizer, acid, and sample solution required for the measurement. Coil 8 may or may not contain a material amount of dilution water at this point, depending on the internal volume of coil 8 relative to the volumes of oxidizer, acid and sample drawn into coil 8 , and also depending upon whether or not the sample requires dilution prior to analysis. [0278] It will be understood that, if the procedure described above took any significant amount of time to complete, there would be an opportunity for oxidizer reagent or, perhaps, even acid, from the sample/reagent end of coil 8 to diffuse into dilution water at the syringe end of coil 8 , which could lead to contamination of the syringe. In practice, however, the several steps of filling coil 8 are completed in a sufficiently short time that there is no opportunity for reagents drawn into the sample/reagent end of coil 8 to diffuse into the dilution water at the syringe end of coil 8 . [0279] In some cases, the source of the sample is a long distance from the analyzer, especially when the analyzer of this invention is used to monitor a process stream of an industrial operation. In such a situation, the analyzer could not provide real-time measurements if the only way of pumping the sample to the analyzer were the syringe pump. Therefore, in a preferred embodiment of the invention, the apparatus also includes a pump 16 which can rapidly draw a fresh portion of sample to the six-way union 17 . Once the new sample portion has been delivered to element 17 , it can be drawn into coil 8 quickly by further opening syringe 6 at the appropriate time. [0280] The next step in the measurement method is to open valve 13 . With valve 13 open, the step of closing syringe 6 results in moving the liquids from coil 8 to a mixing location in the system, such as to the mixer/sparger component 18 , where the reagents, sample, and dilution water, if any, are thoroughly mixed. Particulate material in the sample is kept in suspension so that the solution/suspension is substantially homogeneous. [0281] In one alternative and sometimes preferred embodiment, the acid and oxidizer are first drawn into coil 8 and then are transferred into mixing/sparging chamber 18 . The sample and dilution water (if any) are then drawn into coil 8 and transferred into mixing/sparging chamber 18 where the sample, acid, oxidizer, and dilution water are mixed. Transferring the liquids to the mixing/sparging chamber 18 in two steps has the advantage of preventing premature reaction of IC in the sample with the acidic reagents in coil 8 . Generation of gas in coil 8 (from reaction of IC in the sample with acid) reduces the volume of sample drawn into coil 8 , adversely affecting the accuracy of the measurement. [0282] Mixer/sparger 18 includes a mixing and sparging chamber that also is designed to provide for sparging CO 2 -free gas through the solution/suspension to remove IC, if NPOC is to be measured. For sparging, after the chamber element of mixer/sparger 18 contains the reagents, sample and dilution water (if any), valve 19 opens to allow the sparge gas to bubble through the chamber element of mixer/sparger 18 . The gas can be provided from a pressurized gas cylinder (not shown) or from a pump (not shown) that draws ambient air through an absorber that purifies the air sufficiently for use as a CO 2 -free sparge gas, and/or as a carrier gas, and/or as a purge gas. In either case, the CO 2 -free gas is prepared for use in gas control sub-assembly module 2 . Sub-assembly 2 includes a pressure-regulating device 20 that adjusts the pressure of the gas to about 20 psig. A proportioning valve 21 controls the flow rate of the gas flowing through valve 19 by means of a sparge gas flow sensor 22 . Additionally, a carrier gas flow sensor 23 in another conduit branch can be used to monitor and control the flow rate of the carrier gas to reactor sub-assembly 3 . Additionally, a restrictor 24 in still another conduit branch can be used to provide for a small flow rate of purge gas to the NDIR detector. [0283] In an alternative embodiment, a valve (not shown) can be used to direct the gas that exits the chamber element of mixer/sparger 18 through the gas/liquid separator unit 4 and then to the NDIR sub-assembly 5 . This arrangement would allow the completeness of the sparging process to be monitored. Thus, the sparging is considered complete when the NDIR indicates that the concentration of CO 2 in the sparge gas going to the NDIR has decreased to a very small (negligible) value. [0284] When the sparging and/or mixing in the chamber element of mixer/sparger 18 is complete, valve 25 opens to allow all or a portion of the solution/suspension in the chamber element to be drawn into the interior of reactor 26 by pump 27 . High-pressure reactor inlet and outlet valves 28 and 29 respectively are open at this point. Valves 30 , 31 , 32 , and 33 are closed. The reactor heater 34 is off, and reactor 26 is near ambient temperature. Pump 27 operates until sufficient liquid from chamber 18 has passed through the interior of reactor 26 substantially to rinse out any remaining prior sample and to fill the reactor tube inside reactor 26 . At this point, pump 27 is stopped, and valves 25 , 28 , and 29 close. [0285] Reactor valves 28 and 29 are specially designed in accordance with this invention to allow the valve housings to be flushed after these valves are closed. The flushing step removes excess sample that contains CO 2 formed by the acidification of the IC in the sample. If this CO 2 were not flushed out of the valves, it would cause an error in the subsequent measurement. To flush the reactor valve housings, valves 30 and 31 are opened, and residual liquid and gases in these housings can then be pumped out by pump 27 and replaced by carrier gas. [0286] After the reactor tube of reactor 26 has been filled with sample and reactor valves 28 and 29 have been flushed, valve 31 closes and valve 32 opens to allow carrier gas to flow from sub-assembly 3 through valve 32 , pass through the gas/liquid separator 4 , and then pass to the NDIR detector sub-assembly 5 . Flow of carrier gas at this time is necessary to allow the NDIR detector to reach a steady baseline prior to the subsequent CO 2 measurement. An in-line filter 37 may be provided between gas/liquid separator 4 and the NDIR unit to prevent aerosols from the reactor 26 and/or from gas/liquid separator 4 from entering the optical path 39 of the NDIR detector. [0287] To measure NPOC or TC, the organics contained in the sample portion in the reactor tube of reactor 26 must be oxidized. This oxidation can be made to occur by heating the interior of reactor 26 with a heater 34 , while controlling the temperature using a temperature sensor 35 . The sealed reactor can be heated, for example, to a temperature between about 150° C. and 650° C. (preferably between about 300° C. and 400° C., and between about 350° C. and 390° C. in one preferred embodiment). The heating period may be between about one to thirty minutes, preferably between about two and four minutes, and approximately 3 minutes in one preferred embodiment. During this period, organics are oxidized in the sample portion in the reactor. At the end of that period, heating element 34 is turned off, and fan unit 36 is turned on to blow ambient air over reactor 26 , cooling it rapidly to near room temperature. Because of the small mass of reactor 26 , it is typically cooled by this cooling step to near ambient temperature in less than about 90 seconds. [0288] To measure IC, the liquid inside reactor 26 is not oxidized. The reactor is filled as described above, but reactor 26 is heated only to a temperature sufficient to facilitate formation of CO 2 from bicarbonates and carbonates (i.e., typically to no more than about 100° C.). The subsequent cooling step may in this case be abbreviated or omitted entirely. Furthermore, the oxidizer reagent is not required for IC measurements, and its addition to the sample prior to the reactor step can thus be omitted to reduce operating cost and make the analysis faster. [0289] When the heating and cooling of reactor 26 is completed (or the comparable IC reactor sequence is completed), valves 30 and 32 close, and valves 28 , 29 , 31 , and 33 open. This apparatus configuration allows carrier gas to flow through the reactor tube of reactor 26 , and carry the reactor products through gas/liquid separator 4 , to the NDIR sub-assembly and along the NDIR optical path 39 . [0290] The NDIR measures the absorbance of the CO 2 in the gas flowing along NDIR optical path 39 at a wavelength of approximately 4.26 μm, e.g., 4.26 μm±0.2 μm. As the CO 2 carried from reactor 26 enters and passes through the NDIR, the absorbance measurement begins at a baseline level, rises up to and passes through a maximum level, and then returns to the baseline level that existed before the valves associated with reactor 26 opened. Either the height of the absorbance peak (or the depth of the intensity trough) or the cone-shaped area of the absorbance response curve can be calibrated and used to determine the amount of CO 2 contained in the gas product coming from the reactor. [0291] The NDIR detector of this invention is comprised of three chambers, as seen in FIGS. 2 and 6 . One chamber 38 contains the IR source. The central chamber, which is the NDIR optical path 39 , is the chamber through which the carrier gas and the gas product from reactor 26 (which includes the CO 2 ) flow. The third chamber 40 contains the IR detector. Chambers 38 and 40 are flushed by CO 2 -free gas provided through the conduit that includes flow controller 24 so that CO 2 in the ambient air does not affect the measurements made with the NDIR. The NDIR further preferably includes an associated temperature sensor 41 and an associated pressure sensor 42 , proximately located relative to the NDIR, which monitors atmospheric pressure outside the NDIR (which is essentially the same as the pressure of the CO 2 in the NDIR). The temperature and pressure measurements made respectively by temperature sensor 41 and pressure sensor 42 can be used to compensate the response of the NDIR for variations in the temperature and pressure of the gas being measured. Alternatively, sensors 41 and/or 42 may be omitted if the measurement does not require temperature and/or pressure compensation. [0292] One of the several novel components of the apparatus of this invention is the mixer/sparger 18 . As shown in greater detail in FIG. 3 , the preferred mixer/sparger of this invention includes a liquid inlet/gas outlet section 43 , a middle section 44 , and a liquid outlet/gas inlet section 45 . The top section 43 contains a liquid inlet 43 a and the sparge gas outlet 43 b. The bottom section 45 includes the inlet port 45 b for the sparge gas and the outlet 45 a for liquid. The middle section 44 includes a chamber element 44 a located inside an annular solenoid coil 44 b, which is activated by passing a series of current pulses through it. Such current waveform pulsing causes a magnetic stirrer 46 positioned inside chamber 44 a to rapidly move up and down inside chamber 44 a. In a preferred embodiment, the magnetic stirrer 46 is coated with a corrosion-resistant outer layer, and its up-and-down action under the influence of the solenoid-generated waveform pulses causes the sample, reagents and dilution water, if any, inside chamber 44 a to be rapidly mixed, typically in about 60 seconds or less. [0293] The bottom section 45 of mixer/sparger 18 includes a porous gas disperser 47 , through which sparge gas is directed on its way into chamber 44 a. The pore diameter in the gas disperser 47 may be about 1 μm to 0.125 in., e.g., preferably about 5 μm to 50 μm, and about 18 μm in a preferred embodiment. The small bubbles produced by passing the sparge gas through disperser 47 results in efficient removal of IC from the liquid in chamber 44 a, generally in about 10 seconds to 20 minutes at sparge gas flow rates ranging from about 50 to about 500 cc/min., typically and preferably in about one minute or less at a sparge gas flow rate of about 200 cc/min. [0294] Another of the novel components of the apparatus of this invention are the high-pressure reactor valves 28 and 29 as shown in FIG. 2 , and as illustrated in greater detail in FIG. 4 . These high-pressure reactor valves are included in a preferred embodiment of the present invention. As seen in FIG. 4 , a polymeric or elastic seal 48 is attached to or comprises a front end or section of a moveable plunger element 49 , which is designed to move back and forth inside the housing/valve body 50 when motor 51 is activated. The rear portion of seal 48 is adapted to retain first and second O-rings 52 and 53 respectively, which seal the interior of housing 50 . The front end of seal 48 is sized and shaped to mate with and plug an opening (i.e., an inlet opening or an outlet opening) of reactor 26 when the valve is closed by advancing plunger element 49 . Reactor 26 may be attached to valve housings 50 , for example, using fittings 70 (as seen in FIG. 4 ), which provide a seal that is essentially leak-free at the pressure produced in reactor 26 when the solution/suspension is sealed inside reactor 26 , and reactor 26 is heated. [0295] Seal 48 is enclosed by a seal chamber defined by the valve housing 50 extending from the sealed opening of reactor 26 at least to first O-ring 52 . This chamber can be continuously or periodically flushed with gas using seal chamber ports 54 and 55 as shown in FIG. 4 . (Reactor valves 28 and 29 also each have a third port that is not seen in FIG. 4 . The sample solution/suspension enters or exits the valve and the interior of reactor 26 through that third port.) This apparatus configuration makes it possible to remove any IC or free CO 2 that may be present in the valve housing 50 while the sample is being oxidized/treated in reactor 26 . [0296] FIG. 5 is a schematic illustration of reactor valves 28 and 29 mounted at either end of a reactor 26 . In a preferred embodiment, the reactor heater element 34 has a tubular configuration open at both ends and located inside a heater housing with the reactor 26 mounted inside the tubular portion of heater 34 . In a preferred embodiment, heater 34 comprises a thick-film heating element deposited on an electrically insulating coating on the tubular portion of heater 34 , as shown in FIG. 5 . The tubular portion of heater 34 may be constructed of stainless steel, titanium, or other suitable materials. The two ends of reactor 26 pass respectively through slots (not shown in FIG. 5 ) in the sidewall of the tubular portion of heater 34 . In a preferred embodiment, reactor 26 is a tube constructed of titanium; however, stainless steel, ceramics, and other materials that are sufficiently corrosion-resistant and compatible with the oxidation temperatures of this invention can be used. As previously discussed, the reactor assembly preferably also includes a fan component to cool the reactor after a heating/oxidation step. As seen in FIG. 5 , the outlet (downstream side) of fan 36 is preferably positioned close to one open end of the heater 34 , and is oriented so that a flow of cooling air during a cooling step passes through the heater housing and over both the exterior and interior of heater 34 , and also such that the airflow going through the interior of the tubular portion of the heater 34 during a cooling step passes over the portion of reactor 26 contained within the tubular portion of heater 34 . [0297] The special NDIR detector sub-assembly 5 of this invention is shown in greater detail in FIG. 6 . The NDIR consists of an optical system and an associated NDIR electronic system (as illustrated in the block diagram of FIG. 7 ). The NDIR optical system has three major sections: an IR source compartment 38 , a sample cell/NDIR optical path 39 , and an IR detector compartment 40 . Collimating lenses 58 located at either end of sample cell 39 separate the adjacent sections. In a preferred embodiment, the lenses 58 are constructed of silicon. [0298] In a preferred embodiment, the IR source 56 is a thin-film heater. It may be mounted in plates 59 that are attached to an IR source heater and an IR source temperature sensor. Using the associated NDIR electronic system, the plates 59 and IR source 56 are controlled to a temperature of about 65° C. in one preferred embodiment. [0299] In a preferred embodiment, the IR detector 60 is a pyroelectric, lithium tantalate sensor element. A 4.26 μm filter is mounted in the IR detector in front of the sensor element. This filter selectively passes infrared radiation at the wavelength that is absorbed by CO 2 . Thus, the IR detector 60 measures the IR radiation that passes through the optical path 39 and the filter without being absorbed by CO 2 . [0300] The IR detector 60 may be mounted in plates 61 attached to an IR detector heater and an IR detector temperature sensor. In a preferred embodiment, the IR detector 60 is controlled at a temperature of about 55° C. using the associated NDIR electronic system. [0301] Carrier gas and the gas product from reactor 26 , including the CO 2 , flow through the center section 39 of the NDIR. IR source 56 and IR detector 60 , located in their separate compartments, are isolated from water vapor and potentially corrosive oxidation products by the compartment separation lenses 58 . The chambers 38 and 40 are also sealed, and CO 2 from ambient air is prevented from entering, or at least from remaining in, those chambers by flowing purge gas provided by the gas control sub-assembly 2 . The center section 39 of the NDIR has a gas inlet port 62 and a gas outlet port 63 , through which the carrier gas and the gas product from the reactor, including the CO 2 , flow. As illustrated in FIG. 6 , the gas inlet port 62 may be located proximate to the IR detector end of the NDIR, while the gas outlet port 63 is located proximate to the IR source end of the NDIR. However, the reverse orientation also is effective. [0302] The electronic system for operating the NDIR sub-assembly in a preferred invention embodiment is schematically illustrated in FIG. 7 . As seen in FIG. 7 , the electronic system includes electronic devices selected to provide power to the IR source, the IR source heater, the IR detector, the IR detector heater, and other electrical components. In a preferred embodiment, the electronics control system modulates the power to the IR source at a frequency of 55 Hz. Signals may be generated at other frequencies for operation of other components, such as the bandpass filter and analog-to-digital converter, from a field-programmable gate array (FPGA) as is known in the art. [0303] The FPGA can be adapted or adjusted to generate a 55 Hz clock for the IR source, with a duty cycle suitable for its operation. The IR source driver converts the logic-level clock signal into the pulsed power required by the IR source. The IR source emits infrared light, modulated at 55 Hz. This light reaches the IR detector, attenuated by any CO 2 present in the center section 39 of the NDIR. The IR detector converts the infrared light that it receives back into an electrical signal, with signal content at 55 Hz that is proportional to the infrared light that it receives. The detector bandpass filter is selected or adapted to remove harmonics of the 55 Hz signal and DC offset, low-frequency noise, and high-frequency noise generated by the IR detector. A synchronous circuit, such as a switched-capacitor filter, is used in the detector bandpass filter, with a clock provided by the FPGA at a multiple of 55 Hz. The analog-to-digital converter samples the waveform from the detector bandpass filter, also using a clock provided by the FPGA at a whole number multiple of 55 Hz. For example, a clock of 5500 Hz provides 100 waveform samples per cycle of the IR detector waveform. The FPGA and the microprocessor perform further bandpass filtering of the digitized IR detector signal, centered at the modulation frequency of 55 Hz, to remove detector noise and noise from the AC mains at 50 Hz or 60 Hz. The amplitude of the 55 Hz signal at the output of the digital bandpass filter is then measured. The response of the IR detector is adjusted for temperature, pressure, and flow rate as necessary, and the CO 2 concentration is calculated in the manner described above. Based on the description provided herein, the processing steps described above could readily be implemented by one of ordinary skill in this art using an apparatus in accordance with this invention. [0304] FIG. 8 illustrates a typical response curve of an NDIR during a carbon measurement sequence. The output is in instrument counts, and the counts are proportional to the amount of IR radiation that strikes the IR detector 60 . When there is no CO 2 in section 39 , the response is at its maximum or baseline level. As soon as CO 2 enters section 39 , the response decreases until it reaches a minimum (trough) that corresponds to when the amount of CO 2 in section 39 has reached its maximum (maximum absorbance). As the CO 2 passes out of section 39 , the response returns to its original baseline level. [0305] There are two ways that the response peak (trough) can be used to calculate carbon concentrations in an aqueous sample being tested. The response curve can be mathematically integrated, and the resulting cone-shaped area of the response curve can be related to carbon concentration by one type of mathematical calibration correlation. Alternatively, the height of the peak (depth of the trough) can be measured and related to carbon concentration by another type of mathematical calibration correlation. These mathematical calibration correlations can be developed for a particular instrument according to this invention by performing tests on samples containing known concentrations of IC, OC and/or TC. Basing computations on the measurement of peak height has the advantage that it is relatively unaffected by changes in gas flow rate; and, for that reason, this is the technique used in a preferred embodiment of the present invention. [0306] The present invention has been described in detail with reference to preferred embodiments thereof for illustrative purposes. Although specific terms are employed in describing this invention, they are used and are to be interpreted in a generic and a descriptive sense only and not for purpose of limitation. Accordingly, it will be understood to those of ordinary skill in the art that various changes, substitutions and alterations in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.

4y

BACKGROUND 1. Technical Environment The object of the present disclosure is a device for preventing overfilling of containers, in particular containers intended to contain liquefied gases. 2. Prior Art Such containers, better known as “cylinders,” are widely utilized where a connection to the distribution network for fuel gases has not been provided. For financial and safety reasons it is best that the cylinders should be filled with a predefined maximum quantity of gas, avoiding overfilling and thus excessive internal pressure. For this reason the cylinders are equipped with devices for preventing overfilling, sized to cut off the flow of entering gas when a desired fill level has been reached. Devices of the type described above are known, for example, to the production of the Applicant and include membrane valves. Such valves are of the type that is normally closed and include a perforated membrane in the center, which, becoming deformed under the action of the entering gas, permits its passage. The gas flow is intercepted when a prearranged level of filling is reached and a piston, placed below the membrane and actuated by a cam connected to a float inside the container, thrusts against a seat, closing one section for passage of the gas. The variation of the sections for passage causes a counter-pressure that acts on the membrane in a direction opposite to that of the gas entering the container, closing the entrance orifice. The disadvantages of such solutions are those typical of the applications of valves to membranes, i.e., the greater predisposition to wear and tear and the consequent lesser reliability compared to solutions that use valves in which the closure means is a rigid component. Another inconvenience encountered in the specific application of the device for preventing overfilling of cylinders is represented by the fact that the membrane valve thus conceived makes it difficult to produce a vacuum inside the container. A further drawback encountered is the reduction of the capacity of exiting gas during normal use. Devices for preventing overfilling of cylinders that employ valves without membranes are known, for example, from the American patent U.S. Pat. No. 4,541,464. In this solution the valve is spherical, normally open. The obstructing sphere is kept in the open position by means of a pin constructed on a spherical member connected to a float by means of a cam driver. During the filling operation the float comes out of the container so that it causes the spherical member to rotate by means of the driving action of the cam. The system is sized in such a way that when the filling position is reached, the rotation of the spherical member causes a loss of contact between the pin and the sphere, which is thrust into the closed position of the valve by the force of gravity, besides a possible return spring. A principal drawback of such solutions is represented by the fact of its being sensitive to the inclination and the oscillations of the cylinder, also from the moment that the spherical member rotates as an effect of any kind of deviation of the cylinder's axis from the vertical position. A second problem is represented by the sluggish speed of the system once the maximum fill level of the cylinder has been reached. A further problem with this solution is determined by the number of elements that compose it and the use of spherical members that complicate the operations of construction and assembly, making the device particularly sensitive to size tolerances and coupling. For the same reasons, the reliability of this solution in use is limited. DESCRIPTION OF THE INVENTION The main purpose of the invention is to make available a device for preventing overfilling of containers, in particular devices intended to contain liquefied compressed gas, structurally and functionally conceived so as to avoid all the drawbacks complained of with reference to the prior art cited. This and other purposes that will appear in what follows are confronted and achieved by the invention by means of a device for preventing overfilling of containers accomplished in accordance with the claims that follow. BRIEF DESCRIPTION OF THE DRAWINGS The characteristics and advantages of the disclosure will be better shown by the following detailed description of a preferred example of the device, illustrated by way of example but not limitative, with reference to the units drawn in which: FIG. 1 is a lateral view of a device for preventing overfilling according to the present invention; FIG. 2 is a frontal-section view of the device of FIG. 1 ; FIG. 3 is a lateral-section view of the device of FIG. 1 ; FIG. 4 is a sectional view corresponding to the one in FIG. 3 , in a different operating state of the device of the present invention; FIGS. 5 and 6 are two lateral sections of two details of the device shown in FIG. 1 , in two respective operating states. PREFERRED MODE OF ACTUATING THE INVENTION In the figures, 1 is a comprehensive indication of a device for preventing overfilling of containers according to the present invention. Device 1 is intended to be applied to a container (cylinder B) for liquefied gas under pressure. Device 1 includes an upper channel 2 which has a longitudinal axis Y, connected to the pipe union for supplying and filling of cylinder B. Below channel 2 , device 1 comprises a valve 3 a , below which is installed a lower channel 4 with axis X orthogonal to axis Y, connected with an internal volume V of the cylinder, of known cylindrical form with rounded bottoms, intended to collect the liquefied gas stored in cylinder B. Valve 3 a comprises a valve body 3 , interposed between channels 2 and 4 , in which is defined a gas duct 5 entering the cylinder, extended mainly along the direction of axis Y. The gas duct 5 is delimited, in the directions transversal to axis Y, by an internal surface 6 of valve body 3 . Valve 3 a comprises a rigid closure means 7 having the shape of a truncated cone, on axis Y with the tapered part turned toward channel 4 , axially movable in valve body 3 from and toward a valve seat 8 in order to respectively open and intercept gas duct 5 . Closure means 7 comprises a bottom surface turned toward channel 2 , from which rises an appendix 9 , having a circular base and longitudinally extended along axis Y. Valve 3 a furthermore comprises a guide element 10 , in which is defined a cylindrical cavity 11 , along axis Y, in which appendix 9 is smoothly contained. Guide element 10 , on the side axially opposite to the cavity 11 , comprises a central arch 12 , capable of being entered by the flow of gas entering the cylinder. Guide element 10 is integral with valve body 3 , being equipped with a perimetric annular protuberance 13 , partially nested in an annular seat 14 , located on the inner surface 6 of valve body 3 . Annular protuberance 13 is transverse to axis Y and is provided with a plurality of passages 15 , to allow for the flow of entering gas to valve seat 8 . Valve 3 a comprises a control rod 17 , associated with closure means 7 , being constructed as a piece with it. Rod 17 is longitudinally extended along axis Y, in a position axially opposite with respect to the appendix 9 . According to other variations of the present invention (not shown), in place of valve 3 a other types of valves may be used, for example valves with a membranous closure means controlled by means of a control rod extended longitudinally, analogous to rod 17 . Control rod 17 crosses channel 4 , above which it is bound in a cylindrical axial guide 18 , integral to valve body 3 and working together with guide element 10 to axially guide closure means 7 . Control rod 17 furthermore comprises an end 19 , axially opposite closure means 7 . Device 1 comprises an actuator 16 that can exert a thrusting force F on end 19 of rod 17 in order to urge closure means 7 away from valve seat 8 . Actuator 16 comprises a float 20 , extended inside the interior volume V of cylinder B, and a cam mechanism 21 to exert the thrust F, in a rising phase of float 20 . Thrust F is exerted until it reaches an extreme position preset by float 20 , corresponding to a maximum fill level of cylinder B. Mechanism 21 comprises a member 22 , linked to valve body 3 by a hinge 23 , on which a cam profile 24 is defined. The cam profile 24 is compatible with closure means 7 in order to exert thrust F until it meets end 19 of control rod 17 . During the upward-traveling phase of float 20 , end 19 of rod 17 slides on cam profile 24 until it reaches an end point 25 ( FIG. 4 ). Cam profile 24 is an arc of a circle with its center on hinge 23 so as to hold closure means 7 at a constant distance from valve seat 8 . Cam profile 24 is sized in such a way that when float 20 has reached the extreme position of maximum filling, end 19 is placed in correspondence with point 25 . In this state, thrust F cannot be exerted, and closure means 7 thus becomes subject only to its own force weight P, which causes closure means 7 to fall toward valve seat 8 so as to intercept gas duct 5 . According to a constructible variant (not shown) of the present invention, the fall of closure means 7 is caused, in addition to weight P, by a return spring. Actuator 16 furthermore comprises a lever mechanism 26 for exerting thrust F on rod 17 in a first stage of descent of float 20 starting from its extreme point of maximum filling. Lever device 26 comprises a fulcrum 27 , hinged to member 22 at distance D from hinge 23 , and a first arm 28 extended from fulcrum 27 toward cam profile 24 . First arm 28 [is] compatible with closure means 7 by exerting thrust F, until it meets end 19 of control rod 17 and a second arm 29 . Fulcrum 27 is interposed between first arm 28 and a second arm 29 , integral to float 20 . First arm 28 and cam profile 24 are positioned from the same part with respect to straight line Z, which joins hinge 23 and fulcrum 27 . During the upward-moving phase of float 20 , arms 28 and 29 place themselves in a position aligned with member 22 , in such a way that first arm 28 can rest against member 22 . During the descent phase of float 20 , end 19 of rod 17 slides on first arm 28 until it reaches an end 30 of first arm 28 in correspondence with an intermediate position of float 20 ( FIG. 6 ). In correspondence with the intermediate position of float 20 , the point of end 25 of cam profile 24 and end 30 of first arm 28 are adjacent to each other. Besides the intermediate position, in a second part of the upward-moving phase of float 20 , end 19 of rod 17 moves on cam profile 24 . The functioning of lever mechanism 26 described above thus permits the rearming of cam mechanism 21 , in such a way that end 19 of rod 17 can move on cam profile 24 when the level of cylinder B is lower than the intermediate one, in particular when cylinder B is empty. The present invention allows us to obtain a device for preventing overfilling of containers capable of responding quickly when the maximum fill level is reset. This device does not experience variations of pressure during the filling of the cylinder. The reduced number, compared to other known solutions, of valve components permits the achievement of greater simplicity in the functional geometries and, consequently, fewer rejects in production and greater dependability in usage. In this way the invention fulfills the proposed purpose, at the same time achieving numerous advantages, among which are: a) the use of a valve of the type that is always open allows better performance with respect to implementing the vacuum in cylinders. b) the phenomenon of interrupting filling before it is completed is reduced; c) performance does not depend on the pressure or density of the fluid being handled; d) repetitiveness of the filling operations is improved, because of reduction of variability in the maximum level actually achieved inside of the cylinder in several successive filling operations.

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FIELD OF THE INVENTION The present invention relates to a lighting device, and more particularly to a lighting device whose functions are selectable according to a switching number of a switch element. BACKGROUND OF THE INVENTION Please refer to FIG. 1 , which is a circuit block diagram schematically illustrating a lighting device according to prior art. The color temperature of the lighting device 1 is adjustable and controllable. The lighting device 1 includes a switch element 11 , a driving and control device 12 and a light-emitting source 13 . The driving and control device 12 includes a bridge current rectifying unit 121 , a driving circuit 122 and a counting and control unit 123 . The light-emitting source 13 includes a first light emitting diode (LED) unit 131 emitting a light of a first color temperature and a second light emitting diode (LED) unit 132 emitting a light of a second color temperature. The switch element 11 , for example, can be mounted on the wall, while the driving and control device 12 and the light-emitting source 13 can be disposed in a light body 14 . The switch element 11 is coupled to a power source 9 , e.g. mains electricity, and the bridge current rectifying unit 121 . The bridge current rectifying unit 121 converts the alternating current into direct current. The counting and control unit 123 is electrically connected to the bridge current rectifying unit 121 , the driving circuit 122 and the light-emitting source 13 , counting a switching number of the switch element 11 , which is turned on for receiving the direct current from the light-emitting source 13 , and outputting an enable signal accordingly. The driving circuit 122 drives the first LED unit 131 to emit the light of the first color temperature and/or drives the second LED unit 132 to emit the light of the second color temperature. The details of the operational principle are disclosed in Taiwanese Patent Publication No. M392923, and are not to be redundantly described herein. Unfortunately, it is found that the above-described architecture could not be applied to a lighting device with more than one light body due to the synchronous control problem. For explanation in more detail, please refer to FIG. 2 , which is a circuit block diagram schematically illustrating a light device with two light bodies 14 and 24 . Similar to the lighting device shown in FIG. 1 , respective light-emitting sources 13 and 23 of the light bodies 14 and 24 emit light of corresponding color temperatures according to the switching number of the switch element 11 . However, since the electronic elements, e.g. capacitors, included in the two lighting bodies for the same functions may still differ in specifications or suffer from manufacturing deviations, the time taken for alternating current to enter the lighting body 14 , be converted into direct current by the bridge current rectifying unit 121 and trigger the counting and control unit 123 to count and the time taken for alternating current to enter the lighting body 24 , be converted into direct current by the bridge current rectifying unit 221 and trigger the counting and control unit 223 may be inconsistent. As a result, the light emission of the light-emitting source 13 of the light body 14 may desynchronize with the light emission of the light-emitting source 23 of the light body 24 . For example, light could be emitted or extinguished at different time points for different lighting bodies. Therefore, there is a need to improve such a light device. SUMMARY OF THE INVENTION An object of the present invention is to provide a lighting device under precise synchronization control. In an aspect, the present invention provides lighting device, which comprises: a switch element coupled to a power source; a bridge current rectifying unit in communication with the switch element for converting alternating current received from the power source into direct current; a driving and light-emitting module in communication with the bridge current rectifying unit; and a counting and control unit in communication with the switch element and the driving and light-emitting module for counting a switching number of the switch element, and selectively outputting one or both of a first enable signal and a second enable signal to the driving and light-emitting module to execute a corresponding function according to the switching number of the switch element. In an embodiment, the counting and control unit is a programmable microcontroller or a flip-flop. In an embodiment, the counting and control unit starts over the counting of the switching number of the switch element once the switch element is in an off state for a time period longer than a preset time period. In an embodiment, the counting and control unit includes a capacitor for power supply to the counting and control unit during the preset time period. In an embodiment, the driving and light-emitting module includes a driving circuit; a first LED unit coupled to and driven by the driving circuit for emitting a light of a first color temperature in response to the first enable signal; and a second LED unit coupled to and driven by the driving circuit for emitting a light of a second color temperature in response to the second enable signal. Alternatively, the driving and light-emitting module includes a driving circuit; and an LED unit coupled to and driven by the driving circuit for emitting a light of a first luminance in response to the first enable signal, and emitting a light of a second luminance in response to the second enable signal. In an embodiment, the lighting device further comprises a modulating module coupled to the driving and light-emitting module for fine-tuning luminance of the emitted light. In an embodiment, the modulating module includes a variable resistor and the luminance is changed with resistance of the variable resistor. In an embodiment, the modulating module further includes a knob coupled to the variable resistor and rotatable to change the resistance of the variable resistor. In another aspect of the present invention, the lighting device comprises: a light-emitting source for providing an illumination light; a switch element coupled to a power source; and a driving and control device in communication with the switch element and the light-emitting source for counting a switching number of the switch element, and selectively outputting one or both of a first enable signal and a second enable signal to the driving and light-emitting module to execute a corresponding function according to the switching number of the switch element. In an embodiment, the driving and control device includes a bridge current rectifying unit in communication with the switch element for converting alternating current received from the power source into direct current to be transmitted to the driving and control device. In an embodiment, the driving and control device includes a driving circuit in communication with the light-emitting source; and a counting and control unit in communication with the switch element and the driving circuit for counting the switching number of the switch element, and selectively outputting one or both of the first enable signal and the second enable signal to the driving and light-emitting module to execute the corresponding function according to the switching number of the switch element. In a further aspect, the present invention provides a lighting device, which comprises: a bridge current rectifying unit in communication with a mains switch for converting alternating current from a power source into direct current; a driving and light-emitting module in communication with the bridge current rectifying unit; and a counting and control unit in communication with the mains switch and the driving and light-emitting module for counting a switching number of the mains switch, and selectively outputting one or both of a first enable signal and a second enable signal to the driving and light-emitting module to execute a corresponding function according to the switching number of the switch element. In an embodiment, the counting and control unit selects to output the first enable signal and/or the second enable signal according to a switching-on number of the mains switch, which is realized by counting an alternating-current receiving number from the power source. In an embodiment, the counting and control unit starts over the counting of the switching-on number of the mains switch once the mains switch is in an off state for a time period longer than a preset time period, and the counting and control unit includes a capacitor for power supply to the counting and control unit during the preset time period. BRIEF DESCRIPTION OF THE DRAWINGS The above objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which: FIG. 1 is a circuit block diagram schematically illustrating a lighting device whose color temperature is adjustable and controllable; FIG. 2 is a circuit block diagram schematically illustrating a lighting device with two light bodies; FIG. 3 is a circuit block diagram schematically illustrating a lighting device according to a first embodiment of the present invention; FIG. 4 is a schematic diagram illustrating the use of the lighting device shown in FIG. 3 ; FIG. 5 is a waveform diagram illustrating the operation of the lighting device shown in FIG. 3 ; FIG. 6 is a circuit block diagram schematically illustrating a lighting device according to a second embodiment of the present invention; FIG. 7 is a waveform diagram illustrating the operation of the lighting device shown in FIG. 6 ; FIG. 8 is a circuit block diagram schematically illustrating a lighting device according to a third embodiment of the present invention; and FIG. 9 is a waveform diagram illustrating the operation of the lighting device shown in FIG. 8 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Please refer to FIG. 3 , which schematically illustrates a lighting device according to a first embodiment of the present invention. The lighting device 3 includes a switch element 31 , which is a power supply switch, a driving and control device 32 and a light-emitting source 33 . The driving and control device 32 is electrically connected to or wirelessly coupled to the switch element 31 and a light-emitting source 33 . When the switch element 31 is switched on, the power source 9 supplies electricity for the driving and control device 32 to drive the light-emitting source 33 so as to provide illumination light. On the other hand, when the switch element 31 is switched off, the power source 9 stops supplying electricity to the driving and control device 32 , and thus the light-emitting source 33 becomes extinguished. In this embodiment, the switch element 31 is controlled with a mains switch 38 standing alone on the wall 8 . By manipulating the mains switch 38 , the switch element 31 can be switched on or off. The driving and control device 32 and the light-emitting source 33 may be, but are not necessarily, two elements disposed inside a light body 34 , as shown in FIG. 4 . For example, the switch element 31 may be integrated with the light body 34 to form the lighting device 3 . The light-emitting source 33 includes at least a first LED unit 331 emitting light of a first color temperature, a second LED unit 332 emitting light of a second color temperature, a first transistor 333 coupled to the first LED unit 331 , and a second transistor 334 coupled to the second LED unit 332 . In this embodiment, an example of the light of the first color temperature is cold white light having a color temperature of about 6000K, and an example of the light of the second color temperature is warm white light having a color temperature of about 3000K. Please be noted the implementation of the present invention is not limited to the above-mentioned examples. In this embodiment, the driving and control device 32 includes a bridge current rectifying unit 321 , a driving circuit 322 and a counting and control unit 323 , wherein the bridge current rectifying unit 321 , for example, is a programmable microcontroller or a flip-flop, and the driving circuit 322 and the light-emitting source 33 , for example, can be combined as a driving and light-emitting module 35 . Please be noted the implementation of the present invention is not limited to the above-mentioned examples. When the switch element 31 is switched on, the bridge current rectifying unit 321 converts the alternating current from the power source 9 into direct current, and transmits the direct current to the elements of the driving circuit 322 . On the other hand, the counting and control unit 323 directly receives the alternating current from the power source 9 , and outputs one or both of a first enable signal and a second enable signal, depending on the receiving times of the alternating current from the power source 9 corresponding to a switching number of the switch element 31 . The driving circuit 322 then selectively drives the first LED 331 to emit the light of the first color temperature in response to the first enable signal, and selectively drives the second LED 332 to emit the light of the second color temperature in response to the second enable signal. The counting and control unit 323 includes a capacitor 3231 , which provides power for maintaining the work of the counting and control unit 323 for a certain period of time during the off-state of the switch element 31 . The length of the period of time varies with the specification of the capacitor 3231 . In other words, if the switch element 31 keeps off for a time period longer than the time period the capacitor 3231 can supply power, the counting and control unit 323 would finally lose power and become unable to execute the counting task until the switch element 31 is switched on. Then the counting of the switching number of the switch element 31 will start over after the switch element 31 is switched on again. Likewise, the counting of the switching number of the switch element 31 will start over when the switch element 31 is in an off state for a time period longer than a preset one. Please refer to FIG. 5 , which is a waveform diagram illustrating the operation of the lighting device shown in FIG. 3 . The first time the switch element 31 is switched on, the counting and control unit 323 receives the alternating current from the power source 9 for the first time, and generates and outputs the first enable signal to turn on the first transistor 333 so as to have only the first LED unit 331 driven to emit light of the first color temperature with 100% power. Afterwards, the switch element 31 is switched off for a specified period of time Td and then switched on again to receive the alternating current from the power source 9 before the counting and control unit 323 runs out of the power supplied by the capacitor 3231 . Meanwhile, the counting and control unit 323 generates and outputs the second enable signal to turn on the second transistor 334 so as to have only the second LED unit 332 driven to emit light of the second color temperature with 100% power. Subsequently, the switch element 31 is switched off again and then switched on again to receive the alternating current from the power source 9 within the power supply time period of the capacitor 3231 . This time, the counting and control unit 323 generates and outputs both the first enable signal and the second enable signal to turn on the first transistor 333 and the second transistor 334 , respectively. With the conduction of both the transistors 333 and 334 , partial current flows through the first LED unit 331 and the second LED unit 332 so as to have the first LED unit 331 driven to emit the light of the first color temperature with 50% power and have the second LED unit 332 driven to emit the light of the second color temperature with 50% power. As a result, the lighting device emits light of a third color temperature, which is synthesized from the light of the first color temperature and the light of the second color temperature. If the light-emitting elements included in the first LED unit 331 , each having a color temperature of 6000K, and the light-emitting elements included in the second LED unit 332 , each having a color temperature of 3000K, are distributed in a well mixed manner, the light of the third color temperature will be normal white light having a color temperature of about 4500K. Please refer to FIG. 6 , which is a circuit block diagram schematically illustrating a lighting device according to a second embodiment of the present invention. The lighting device 3 ′ in this embodiment is similar to the light device 3 in the first embodiment except that the lighting device 3 ′ further includes a modulating module 36 coupled to the switch element 31 and the driving and control device 32 for modulating luminance of the light-emitting source 33 . In this embodiment, the modulating module 36 includes a variable resistor Rs, capacitors C 1 , C 2 and bidirectional triode thyristors T 1 , T 2 . When the switch element 31 is switched on, the alternating current entering the bridge current rectifying unit 321 from the power source 9 can be modulated by changing the resistance of the variable resistor Rs. In this embodiment, the modulating module 36 is, but not necessarily, manipulated by way of a knob 37 disposed under the mains switch 38 , as shown FIG. 7 . The knob is coupled to the variable resistor and rotatable to change the resistance of the variable resistor. The bridge current rectifying unit 321 then converts the modulated alternating current into direct current to be transmitted to elements included in the driving circuit 322 . Accordingly, the lighting device 3 provides light with luminance corresponding to the resistance of the variable resistor Rs. Please refer to FIG. 8 , which is a circuit block diagram schematically illustrating a lighting device according to a third embodiment of the present invention. The common elements included in the lighting device of this embodiment and the lighting device of the first embodiment are not to be redundantly described herein. The lighting device of this embodiment differs from the lighting device of the first embodiment in further comprising another bridge current rectifying unit 421 , another driving circuit 422 , another counting and control unit 423 and another light-emitting source 43 . The bridge current rectifying unit 421 , driving circuit 422 , counting and control unit 423 and light-emitting source 43 work identically to those described in the first embodiment. For example, the counting and control unit 423 is directly coupled to the switch element 31 . In this embodiment, the driving circuit 422 and light-emitting source 43 are elements of another light body 44 , as shown in FIG. 9 . The respective light-emitting sources 33 and 43 of two light bodies 34 and 44 included in the lighting device of this embodiment are controllable with a single switch. In this embodiment, since the two counting and control units 323 and 423 are both coupled to the switch element 31 and outputs enable signals directly according to the receiving status of the alternating current, the respective light-emitting sources 33 and 43 of two light bodies 34 and 44 emit light synchronously. In other words, by having the two counting and control units 323 and 423 differentially outputs enable signals directly according to the receiving times of the alternating current, the desynchronizing problem encounter by the prior art due to the time variations resulting from inconsistent specifications or manufacturing processes of the elements, e.g. capacitors, included in different light bodies can be avoided. The above three embodiments are just examples given for better understanding the present invention, and can be modified by those skilled in the art according to practical designs and needs. For example, the modulating module 36 used in the second embodiment can also be added into the lighting device in the third embodiment. Furthermore, although each of the lighting devices described in the above three embodiments changes color temperatures of light according to the switching-on number of the switch element, it may be modified to have the color temperatures of light changed according to the switching-off number of the switch element without difficulties based on the disclosure as above. For example, when the switch element 31 is first switched on, the driving circuit 322 drives the light-emitting source 33 to emit light of a first luminance in response to the first enable signal generated by the counting and control unit 323 ; and when the switch element is switched off and then switched on after a specified period of time, the driving circuit 322 drives the light-emitting source 33 to emit light of a second luminance in response to the second enable signal generated by the counting and control unit 323 . In another example, when the switch element is first switched on, the lighting device emits light for illumination, and when the switch element is switched off and then switched on after a specified period of time, the lighting device provides a radio frequency identification (RFID) sensing function. Afterwards, when the switch element is switched off again and then switched on again, the lighting device suspends both the illumination and RFID sensing function. While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.

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