A support particularly adapted for supporting a geomatic pole has telescoping legs, each having telescoping leg sections which can be locked by a locking device in a selected position of extension, fixing the length of the leg. The locking device is easily actuated and released and is biased toward a locked position. In an unlocked position, the locking device is positively positioned to inhibit contact with the released leg section so that movement is smooth and unnecessary wear is limited. The locking device has an engagement portion which is constructed to promote locking, but also to facilitate release and limit unnecessary wear of the engagement portion.

This invention relates generally to devices which support and hold equipment and more particularly to a foot for such devices suitable for holding geomatic equipment and accessories.
Although the art of surveying is old, recent improvements in equipment, such as automatic electronic total surveying stations, have increased the accuracy of the surveying instruments far beyond what was possible previously. Where accepted accuracy for equipment in the not too distant past was 20 seconds of a degree, accuracy is now commonly required to be 1 second of a degree. At these levels of precision, the instruments and many of their accessories must be supported in a manner which is consistent and stable. Accordingly, there is a need for closer examination of support structure used for surveying equipment so that improvements in instrumentation will not be lessened by inadequate supports. Further, the cost of surveying equipment makes it highly undesirable to damage it by failure of the supports because of instability.
Pole supports used in the surveying field typically take the form of bipods or tripods, but conceivably any number of legs could be provided. Conventionally, it has been necessary to provide completely separate inventories of bipods and tripods to meet the needs of different customers and for different applications. Legs of these supports are usually freely pivotable about a head of the support to swing toward each other for ease of carrying the support when not in use. A support having three or more legs can support equipment or other items above and out of contact with the ground. Typically, bipods are used to support surveying equipment such as a surveying pole, which also contacts the ground, but tripods may also be used to support surveying poles. The stability of such supports can be compromised in situations where there are forces (e.g., wind and loads from the surveying equipment) acting on the support and tending to tip the support over. In that case, one of the legs is subjected to an upward force component tending to raise the leg up as the support pivots about a point(s) of contact of the other leg(s) with the ground.
Presently, there is little or no resistance provided by the legs to such upward forces other than the weight of the leg. Even if there are stakes associated with the legs that penetrate the ground, the upward force tends to be directed right along the long axis of the stakes so that they are lifted out of the ground. The problem is compounded by the fact that the legs conventionally are mounted for pivoting freely about a horizontal axis. Even if the support does not tip over, if one leg loses contact with the ground or the frictional resistance to pivoting movement of the leg becomes sufficiently small, the leg will swing in toward the center of the support. The support is unlikely to regain stability when this happens. Should the support move back toward its original position, the leg having pivoted inwardly is no longer in position to engage the ground in a stable position. The center of gravity of the combined support and surveying equipment may lie outward of the point where the leg re-contacts the ground so that the entire unit topples over in the opposite direction from the initial tipping movement. Alternatively as the leg pivots inwardly, the weight of the leg exerts a smaller torque resisting the tipping motion so that the motion may continue causing the unit to collapse. If instability of the support causes it to move, even where it does not fall over, accuracy is compromised.
The legs of the support are most often telescoping so that their length may be adjusted as needed so that, for instance, the support can be set up on uneven terrain or the ends of the legs contact the ground at different leg angles. In the situation where the support is used with a surveying pole, the legs are manipulated so that the pole is precisely located over a selected point. When the telescoping legs are extended, it is necessary that they be locked at a specific length. Locking systems work most commonly by greatly increasing the frictional engagement of one leg section with the other. These systems suffer from certain drawbacks. Some locking systems may have a component of motion which is parallel to the lengthwise extent of the leg when engaged. This movement can cause the length of the leg to change during engagement of the locking system and result in loss of precision in the position of a surveying pole held by the support. The leg sections may be difficult to move relative to each other because of residual frictional engagement of the leg sections caused by the locking system, even when the locking system is released. In that situation movement may be jerky, making it difficult to extend or retract the leg to a precise length. Moreover, it is conventionally necessary to manually hold the locking device to keep the leg sections unlocked. This makes manipulation of the legs difficult, particularly where there are more than two legs. Conventionally, the leg sections are assembled at the factory and cannot be readily taken apart. Accordingly, cleaning and repair in the field is difficult.
Although the present invention has particular application for use in supporting surveying and geographic positioning equipment, it is not limited to such applications. As used herein "geomatic" is intended to encompass surveying and geographic positioning. The invention is envisioned as being useful to support equipment and other items having no relation to surveying or geographic positioning.

Geomatic pole support with telescoping legs and locks


The present invention provides methods and compositions for the treatment and diagnosis of diseases such as neoplastic diseases, neurodegenerative diseases, cardiovascular diseases, autoimmune diseases, and inflammatory diseases. The methods are based on the concept of pretargeting and include the administration of complexes comprising a recognizable compound A coupled to annexins, and the administration of complexes comprising of pharmaceutical or diagnostic compounds coupled to a compound B recognizing and binding to compound A to subjects. The compositions include annexins, annexin variants, that are not internalized by the target cells, derivatives thereof, and complexes thereof.

Cells are enveloped by a plasma membrane ("PM") that consists of a bilayer of phospholipid molecules and several protein molecules. Various phospholipid molecules form the building blocks of the bilayer. The phospholipid molecules are distributed asymmetrically over the two leaflets of the bilayer. Phosphatidylcholine for example is present in both layers, whereas sphingomyeline can be found only in the outer leaflet facing the environment. Aminophospholipids, like phosphatidylserine ("PS"), on the other hand, are predominantly present in the inner leaflet facing the cell's cytosol (Zwaal and Schroit, Blood 89:1121-32 (1997)). Aminophospholipid translocases transport PS from the outer to the inner layer, or leaflet, of the plasma membrane to create an asymmetric distribution of PS. The asymmetric architecture of the PM is a feature of living cells. They expend energy to generate and maintain the uneven distribution of the phospholipid species in their PM's.
A cell can change the phospholipid architecture of its PM under certain circumstances, which lead to activation and perturbation of the cell. Programmed cell death ("PCD") is associated with the appearance of PS in the outer leaflet of the PM (Fadok et al., J. Immunol. 148:2207-16 (1992)). On the basis of morphology and biochemistry, at least four types of PCD have been identified: (1) apoptosis, (2) apoptosis-like PCD, (3) necrosis-like PCD, and necrosis. Each type is accompanied by a change in the asymmetry of the PM characterized by exposure of PS to the outer layer of the cell surface. PS exposure at the outer layer of the PM is a good indication of a variety of activated and perturbed states of a cell. PS exposure, however, is not exclusively associated with cellular processes culminating in cell death. Transient and reversible PS exposure has been reported for several cell types, including activated B cells, undifferentiated muscle cells prone to form syncytium, chlamydia infected cells, endothelial cells of tumour vasculature (U.S. Pat. No. 6,312,694), and engulfing macrophages (Kenis et al. J. Biol. Chem. 2004 279: 52623-9). In addition, several cellular processes and conditions have been found that are associated with an expression of PS at the outer leaflet of the PM. These include platelet activation, red blood cell ageing, stimulation of the immune system, muscle cell syncytium formation, new blood vessel formation in tumors (U.S. Pat. No. 6,312,694), and tumor growth (Rao et al., Thromb. Res. 67:517-31 (1992)).
In addition, cells can dissipate portions of themselves from their surface resulting in membrane encapsulated microparticles. These microparticles have aminophospholipids such as PS exposed at the outer layer of the membranes. These microparticles have been associated with diseases like infection, AIDS, atherosclerosis. Therefore, aminophospholipids at the cell surface are indicators of a variety of activated and perturbed states of a cell. Moreover, microparticles that exhibit exposed aminophospholipids reflect distant cell activation and perturbation. Hence, phospholipids at the surface of a PM constitute attractive targets for a variety of purposes including research, diagnosis, prevention and treatment of diseases. Preferably, PS in the outer leaflet of a PM constitutes a target for research, diagnosis, prevention and treatment of diseases.
Pharmacological and genetic treatments of diseases are based on the delivery of pharmacologically active compounds to diseased cells where the compounds act preferably intracellularly. Current therapeutic treatments employ systemic delivery of a drug, where the drug circulates through the entire body before reaching its desired target. This method of drug delivery results in systemic dilution of the compound. As a result higher concentrations of the drug are required to achieve a therapeutic efficacy. This is associated with undesired toxic side-effects and increased costs of drugs.
Solutions to these problems are provided by targeted drug delivery systems. The targeting agent, which is coupled to the drugs directly or indirectly, guides the drugs to the diseased cells where they accumulate.
Recently we described annexins, derivatives thereof and annexin-Cys variants as targeting and cell-entry agents and their uses for therapeutic and diagnostic applications (WO 2006/003488, published 12 Jan. 2006). The predominant target of annexins is phosphatidylserine (PS), which is exposed by cells that execute programmed cell death or are submitted to stress such as metabolic stress. The annexins, derivates and annexin-Cys variants as described in WO 2006/003488 bind to cell surface exposed PS and are subsequently internalized. The internalization results in a depletion of surface-bound annexins. This phenomenon disfavours the use of annexins in therapeutic and diagnostic procedures that employ the concept of pretargeting.
Pretargeting is a strategy of targeting a reporting compound for diagnostic purposes and/or a drug for therapeutic purposes to the diseased tissue in a multi-step procedure in order to reduce the background signal and the systemic toxic burden respectively. The pretargeting concept employs two compounds A and B which have a high affinity for each other. Compound A encompasses the targeting function and compound B contains the reporter and/or therapeutic function. Firstly, compound A with the targeting function is administered to the subject. After a certain period of time when the circulating compound A is cleared sufficiently, compound B with the reporter and/or therapeutic drug is given to the subject. The latter compound will accumulate at sites where compound A is retained due to its targeting function. This strategy reduces the amount of compound B that needs to be administered in order to obtain the desired effect. Moreover, it will circumvent background signals and undesired toxic side-effects that are related to compound A if the reporter and/or therapeutic drug were directly coupled to compound A.
Examples of combinations of A and B compounds that have high affinity for each other and that are suitable for pretargeting include the streptavidin/avidin and biotin combination, combination of complementary DNA and RNA oligonucleotides, complementary DNA and RNA analogs such as morpholinos (synthetic oligonucleotide analogues containing morpholino-phosphorodiimidate chains instead of deoxyribose-phosphodiester chains), peptide nucleic acids (synthetic oligonucleotide analogues containing N-aminoethyl-glycine chains instead of deoxyribose-phosphodiester chains, PNA) and aptamers (specifically binding oligonucleotides or oligopeptides), the antibody and hapten combination, and the receptor and ligand combination. These combinations have been used in delivery of radionuclides for imaging and therapy of cancer through the pretargeting strategy (Sharkey et al, Clin. Cancer Res. 2005, 11:7109-21).
The prerequisite for successful implementation of the pretargeting strategy is the accessibility of compound A for compound B. Internalization of compound A by the target cell would reduce the efficacy of this strategy.
Patent application WO 2006/003488, describes that annexins, derivatives thereof, and annexin-Cys variants are internalized by cells that expose PS at their surface. The mechanism of internalization is based on the formation of annexin-trimers and the organization of the annexin-trimers in large 2-dimensional networks (Kenis et al. J. Biol. Chem. 2004 279: 52623-9). This mechanism, thus, diminishes the efficient use of annexin, derivatives thereof, and annexin-Cys variants as targeting parts of compound A in pretargeting strategies.
Mira et al., J. Biol. Chem. 1997, 272: 10474-82, describe annexin mutants M1-M4, which affect Ca2+ binding and the effect thereof on inhibition of cytosolic phospholipase A2.

Annexin derivatives suitable for pretargeting in therapy and diagnosis


A device for milking animals includes a milking robot for automatically connecting at least two teat cups to the teats of an animal to be milked. The milk yielded is collected in a milk container. In each milk line, between a respective teat cup and the milk container, there is provided an auxiliary reservoir for collecting milk obtained at the beginning of the milking process. The auxiliary reservoir has an outlet aperture with a closing device. Each auxiliary reservoir is disposed in a respective mounting block, the various mounting blocks being arranged side by side, and the device is provided with an arrangement for simultaneously operating the closing devices.

1. Field of the Invention
The present invention relates generally to devices for milking animals and in particular to milking robots for automatically connecting teat cups to the teats of an animal to be milked.
2. Description of the Related Art
A device is known from U.S. 2001/0054392 A1, the contents of which are incorporated by reference in their entirety, in which a milk container is provided for the milk yielded and an auxiliary reservoir is disposed in each milk line between a respective teat cup and the milk container. A particular quantity of milk, substantially obtained at the beginning of the milking process, is collected in each auxiliary reservoir via an inlet aperture and can leave the auxiliary reservoir via an outlet aperture having a closing device. The milk obtained thereafter is led to the milk container. Such an arrangement can be applied, for example, to a device for milking animals as described in U.S. 2004/0094096 A1, the contents of which are also incorporated by reference in their entirety.
The present invention aims at improving the combination of these devices.


The improved polyamide production method of the present invention is characterized by including a step of accurately regulating the molar balance between a diamine component and a dicarboxylic acid component to a desired balance in a batch-wise regulation tank, thereby preparing a slurry liquid substantially free from the amidation reaction. The slurry liquid thus prepared is fed to a batch-wise or continuous polymerization reactor, where the amidation reaction is proceeded to easily produce polyamide having a desired balance of the diamine component and the dicarboxylic acid component without causing a problem such as foaming, solidification, etc.

1. Field of the Invention
The present invention relates to a process for producing polyamide. More specifically, the present invention relates to a process for producing polyamide, comprising a step of preparing a substantially amidation-free slurry liquid comprising a xylylenediamine-rich diamine component and a dicarboxylic acid component in a batch-wise regulation tank. The slurry liquid is fed to a batch-wise or continuous polymerization reactor as a starting material to produce polyamide.
2. Description of the Prior Art
In the production of polyamide from a diamine component and a dicarboxylic acid component, an accurate molar balance between the diamine component and the dicarboxylic acid component is quite important for achieving an intended polymerization degree. To produce polyamide having an intended molar balance, special care is usually taken in accurately controlling the charge amounts of the diamine component and the dicarboxylic acid component as well as in preventing the diamine component from escaping from the reaction mixture. Although a batch-wise polymerization is clearly advantageous over a continuous polymerization with respect to the easy control of the molar balance, the production of polyamide by a continuous polymerization is also under consideration due to its low heat history and industrial advantages.
The charge amounts of the constitutional components of polyamide can be accurately controlled by adjusting pH when a nylon salt or its aqueous solution is used as the starting material to be fed to a polymerization reactor. However, there arises a problem attributable to the use of the nylon salt or its aqueous solution as the starting material.
In batch-wise polymerization using an aqueous solution of nylon salt, the polycondensation is conducted in the same reactor by heating a 50% aqueous solution of nylon salt under pressure, allowing the polycondensation to proceed in homogeneous phase while preventing the diamine component from escaping, and gradually releasing water vapor from the reactor after fixation of the diamine component to finally reach ordinary pressure or reduced pressure, thereby completing the polycondensation.
Known continuous polymerization is usually carried out by two or three stages according to the intended polymerization degree. In the first stage, an aqueous solution of nylon salt is fed to a reactor and subjected to polymerization therein to produce prepolymer. In the second stage, the prepolymer is separated from water and is further polymerized to reach the intended polymerization degree. Since the continuous polymerization is industrially advantageous as compared with the batch-wise polymerization, various techniques for the continuous polymerization using an aqueous solution of nylon salt as the starting material is disclosed in Japanese Patent Publication Nos. 44-22510, 49-20640, 56-46487, 5-52333, etc. However, the proposed methods requires a highly pressure-resistant vessel to prevent water used as the solvent from escaping in the initial stage of polymerization. In the final stage of polymerization, a large amount of water used as the solvent and the condensation water should be removed, and such removal requires means for avoiding various disadvantages such as foaming, solidification of polymer due to evaporation latent heat of water, etc. In addition, the removal of a large amount of water requires a high heat-energy consumption. Thus, the conventional continuous process using an aqueous solution of nylon salt involves various technical and economical problems.
Japanese Patent Publication No. 44-3838 proposes a continuous polymerization using a nylon salt as the starting material. However, the proposed process is not efficient because additional steps for isolation and purification of nylon salt are required.
U.S. Pat. No. 5,674,974 discloses a continuous polymerization using no nylon salt or no aqueous solution of nylon salt as the starting material. In the proposed process, a molten dicarboxylic acid component or a molten dicarboxylic acid-rich component is fed to a multistage reactor, and a vapor or liquid diamine component is fed at the second and subsequent stages while controlling the molar balance of the dicarboxylic acid component and the diamine component by a feedback control system utilizing near infrared spectroscopy. However, unlike the use of nylon salt or its aqueous solution, the process where the monomer components are separately and continuously fed into a continuous polymerization reactor is less accurate in the charge amounts, and it is difficult to achieve, by a flow controller, a molar balance sufficiently accurate for controlling the polymerization degree of polyamide. Therefore, the proposed process requires to detect and adjust the molar balance throughout the polymerization step.
In stead of using nylon salt or its aqueous solution, the best alternative for controlling the molar balance between charged polyamide-constituting components is a method where the amounts of the diamine component and the dicarboxylic acid component are separately measured in batch-wise manner by a mass measuring device such as a load cell, and then each component is fed into the reactior. For example, known is a method in which a molten dicarboxylic acid component is fed to a reactor after measuring its amount by a mass measuring device, and then a diamine component is fed to the reaction system while measuring its amount by a mass measuring device, thereby controlling the molar balance of the dicarboxylic acid component and the diamine component. As disclosed in Japanese Patent Application Laid-Open No. 58-111829, this method is suitably applicable to produce polyamide by a polymerization under ordinary pressure without using nylon salt as the starting material. However, since the mixing of the diamine component with the dicarboxylic acid component is carried out at a temperature higher than the melting point of the dicarboxylic acid component, the amidation proceeds remarkably. In addition, when the mixture is finally subjected to a continuous polymerization, the variation in polymerization degree detrimentally occurs due to the different residence times in transferring the mixture from a batch-wise regulation tank to a continuous polymerization reactor. Therefore, the mixture (reaction product) of the dicarboxylic acid component and the diamine component prepared by this method cannot be a stable starting material for the polymerization.
An object of the present invention is to provide a method for producing polyamide without using nylon salt or its aqueous solution as the starting material to be fed to a polymerization reactor, in which a molar-balanced mixture of a diamine component and a dicarboxylic acid component being substantially free from amidation reaction is prepared by using a batch-wise mass measuring method capable of accurately controlling the molar balance between the diamine component and the dicarboxylic acid component (hereinafter may be referred to as xe2x80x9cmolar balancexe2x80x9d), and the resultant mixture is fed to a batch-wise or continuous polymerization reactor where polyamide is suitably produced.
As a result of extensive studies, the inventors have found that a mixture of a diamine component comprising 80 mol % or more of xylylenediamine and a dicarboxylic acid component provides an extremely stable, uniform slurry free from amidation when prepared in the absence of a solvent at a temperature within a specific range and at a specific water content.
Thus, in an aspect of the present invention, there is provided a process for producing polyamide by polymerization of a diamine component comprising 80 mol % or more of xylylenediamine and a dicarboxylic acid component, comprising the steps of (1) feeding the diamine component to a batch-wise regulation tank after accurately measuring the mass of the diamine component; (2) adding the dicarboxylic acid component to the liquid diamine component in the batch-wise regulation tank in an amount so as to attain a desired molar balance between the diamine component and the dicarboxylic acid component while stirring the liquid diamine component, thereby preparing a slurry liquid substantially free from amidation; and (3) feeding the slurry liquid to a polymerization reactor as a starting material for the polyamide.
In another aspect of the present invention, there is provided a process for producing polyamide by polymerization of a diamine component comprising 80 mol % or more of xylylenediamine and a dicarboxylic acid component, comprising a step (1) of preparing a substantially amidation-free slurry liquid comprising a diamine component and a dicarboxylic acid component, by feeding the diamine component to a batch-wise regulation tank after accurately measuring the mass of the diamine component, and adding the dicarboxylic acid component while stirring the liquid diamine component in the batch-wise regulation tank in an amount so as to attain a desired molar balance between the diamine component and the dicarboxylic acid component; a step (2) of continuously feeding the slurry liquid to a continuous polymerization reactor configured so as to minimize the escape of a vapor phase component from a reaction system and ensure complete vapor-liquid mixing, heating the slurry liquid to proceed amidation reaction, and heating the polyamide being produced to a temperature of a melting point thereof or higher; and a step (3) of increasing a polymerization degree by removing condensation water generated by the amidation reaction from the polyamide at a temperature of the melting point thereof or higher.
In the present invention, a diamine component comprising 80 mol % of xylylenediamine and a dicarboxylic acid component are used as the polyamide-constituting components. Xylylenediamine may include m-, p- and o- xylylenediamine and may be a mixture thereof. The mixing ratio of the xylylenediamine isomers is not critical and may be arbitrarily selected as far as the melting point of the xylylenediamine mixture is 80xc2x0 C. or lower. One of the reasons for using xylylenediamine suitably in the present invention is that the boiling point of xylylenediamine is higher than the melting point of polyamide. To obtain polyamide having a predetermined molar balance, it is important to increase the accuracy of the charge amounts of the starting diamine component and dicarboxylic acid component as well as to efficiently fix the diamine component during polymerization. In this point of view, the boiling point of xylylenediamine higher than the melting point of polyamide is greatly advantageous for efficient fixation of the diamine component and control of the molar balance. As the diamine component other than xylylenediamine, usable are tetramethylenediamine, hexamethylenediamine, 1,3-bisaminomethylcyclohexane, etc.
The dicarboxylic acid component may include adipic acid, succinic acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, etc. These dicarboxylic acids may be used alone or in combination of two or more. In view of practical properties of polyamide to be produced, the dicarboxylic acid component preferably comprises 50 mol % or more of adipic acid. In addition to the diamine component and the dicarboxylic acid component, the polyamide-constituting component may include a lactam such as caprolactam, valerolactam, laurolactam, undecalactam, etc. or an aminocarboxylic acid such as 11-aminoundecanoic acid, 12-aminododecanoic acid, etc., in such an amount as not adversely affecting the most important feature of the present invention, i.e., the preparation of an amidation-free slurry liquid.
The molar balance of the monomers constituting polyamide after the polymerization (hereinafter referred to as xe2x80x9cpolyamide molar balancexe2x80x9d) may be diamine component-rich, dicarboxylic acid component-rich or equimolar with respect to the diamine component and the dicarboxylic acid component. To achieve an intended polyamide molar balance, generally, the molar balance of the charge amounts of the materials for polyamide is preferably set to diamine component-excess to make up for the loss of the diamine component by escaping from the reaction system together with condensation water resulted from the amidation reaction, and the charge ratio (diamine component/dicarboxylic acid component by mole) is generally selected so that the diamine component is excessive as compared to the intended polyamide molar ratio by 0.0005 to 0.005. In the present invention, a mass measuring device such as a load cell and a balance is suitably used for measuring the masses of the diamine component and the dicarboxylic acid component. For example, a predetermined amount of each of the diamine component and the dicarboxylic acid component is fed to a batch-wise regulation tank while measuring their masses by monitoring the change in the mass of measuring tanks respectively storing the diamine component and the dicarboxylic acid component.
During the addition of the dicarboxylic acid component to the liquid diamine component in a batch-wise regulation tank and after the addition until the slurry liquid is fed into a polymerization reactor, the temperature of the diamine component and the slurry liquid is preferably kept at a temperature from the solidification temperature of the diamine component to 80xc2x0 C. When kept lower than the solidification temperature of the diamine component, the reaction system cannot be uniformly mixed by stirring and the feed of the slurry liquid to a polymerization reactor becomes difficult. When the temperature of the diamine component or the slurry liquid exceeds 80xc2x0 C., the formation of nylon salt becomes remarkable to cause a thermal accumulation of neutralization heat, thereby steeply raising the temperature of the reaction system. The temperature rise further accelerates the formation of nylon salt. Since the formed nylon salt gives a granular mixture in stead of slurry liquid, the uniform mixing by stirring is prevented. Such a steep rise of the temperature and the local overheat initiate the amidation reaction, and as a result thereof, condensation water is evolved into the reaction system. Since water catalyzes the formation of nylon salt, the formation of nylon salt and the amidation reaction continue in succession. The formation of nylon salt and the amidation reaction do not generate sufficient heat for making polyamide uniform liquid state, and therefore, the reaction system becomes bulky to make uniform mixing by stirring completely impossible.
In the present invention, a uniform and stable slurry liquid comprising the diamine component and the dicarboxylic acid component which are substantially free from amidation can be prepared without needing a solvent during and after the addition of the dicarboxylic acid component to the liquid diamine component in a batch-wise regulation tank. Therefore, the method of the present invention can be carried out in the absence of the solvent. In the present invention, xe2x80x9csubstantially amidation-freexe2x80x9d or xe2x80x9csubstantially free from amidationxe2x80x9d can be confirmed by no detectable condensation water formed by amidation.
The water content in the slurry liquid prepared in the batch-wise regulation tank is preferably 0.7 mass % or less, more preferably 0.5 mass % or less based on the amount of the slurry liquid. When higher than 0.7 mass %, the formation of nylon salt becomes remarkable even when the diamine component or the slurry liquid is maintained at 80xc2x0 C. or lower because water catalyzes the formation of nylon salt, and as a result thereof, the temperature of the reaction system is rapidly raised due to the accumulation of neutralization heat, this further accelerating the formation of nylon salt. Therefore, as described above, the amidation reaction begins and the formation of nylon salt and the amidation reaction continue in succession by the action of condensation water being evolved. Since the formation of nylon salt and the amidation do not generate sufficient heat for making polyamide uniform liquid state, the reaction system becomes bulky to make uniform mixing by stirring completely impossible.
The diamine component to be fed into the batch-wise regulation tank may be liquid or solid, and preferably liquid having a temperature from its solidification point to 80xc2x0 C. for easiness of handling and for the same reasons mentioned above. Also, for the same reasons mentioned above, the water content of the diamine component is preferred to be low. Commercially available diamines are generally purified by distillation, general products industrially produced have a water content (usually, 0.1 mass % or less) suitable for use in the present invention. Therefore, commercially available diamines can be used as such without needing any additional drying operation. After measuring the mass by a mass measuring device, the diamine component meeting the above requirements is fed into the batch-wise regulation tank. The measurement of the mass is preferably carried out in an inert gas such as nitrogen.
The dicarboxylic acid component to be added to the diamine component in the batch-wise regulation tank may be liquid or solid. The temperature of the dicarboxylic acid component is preferably 80xc2x0 C. or lower for the same reasons mentioned above. Also, for the same reasons mentioned above, the water content of the dicarboxylic acid component is preferred to be low. Dicarboxylic acids industrially produced usually have a water content of 0.1 to 0.2 mass %, and suitable for use in the present invention. After measuring the mass by a mass measuring device, the dicarboxylic acid component meeting the above requirements is fed into the batch-wise regulation tank. The measurement of the mass is preferably carried out in an inert gas such as nitrogen.
The batch-wise regulation tank used in the present invention is not strictly limited as far as it has an agitation capacity and an agitation power sufficient for preparing a uniform slurry liquid. After the slurry liquid is prepared and until the resultant slurry liquid is fed into the polymerization reactor, the agitation in the batch-wise regulation tank may be continued or discontinued. To avoid the oxidation of polyamide, the oxygen content of the slurry liquid is reduced to as low a level as possible. For this purpose, the batch-wise regulation tank preferably has a construction capable of replacing its inner atmosphere with an inert gas such as nitrogen.
By the sequential use of two or more batch-wise regulation tanks, the slurry liquid prepared in the batch-wise regulation tanks can be continuously fed into the polymerization reactor as the material for polyamide production. Since the slurry liquid in the batch-wise regulation tank is substantially free from amidation, is homogeneous and is stable, the properties of the slurry liquid are independent of the difference in residence time even in the continuous production of polyamide by feeding the slurry liquid into a continuous polymerization reactor. Therefore, the transfer from the batch-wise step for preparing the slurry liquid, i.e., the step for adjusting the molar balance of the material to the continuous step for polymerization is easy.
When the slurry liquid prepared by the method of the present invention is fed into a batch-wise polymerization reactor, a reactor equipped with a partial condenser operated at ordinary pressure or under pressure is preferably used to maintain the molar balance achieved in the preparation step of the slurry liquid. However, since the boiling point of xylylenediamine is higher than the melting point of polyamide, the pressure can be set to fairly low pressure, for example, about 0.5 MPa or lower, as compared with the process using an aqueous solution of nylon salt as the starting material. In the batch-wise production, it is advantageous to rapidly raise the temperature of the slurry liquid to the melting point of polyamide, and therefore, the use of a large L/D horizontal reactor having a large heat transfer surface and a multi-stage stirring paddle is preferable. When a reactor of tank type is used, the amidation reaction is carried out by feeding the slurry liquid into the reaction system little by little while maintaining the reaction system at a temperature higher than the melting point of polyamide. Thus, the batch-wise amidation reaction is preferably carried out at a temperature from the melting point of polyamide being produced to a temperature of the melting point of polyamide+30xc2x0 C. not exceeding 300xc2x0 C. usually for 0.5 to 6 hours.
As described above, water catalyzes the formation of nylon salt in the slurry liquid to generate a large quantity of neutralization heat, this further promoting the amidation reaction. Therefore, it is highly advantageous for promoting the production of polyamide to add a small amount of water as the catalyst to a batch-wise polymerization reactor together with the slurry liquid. The addition amount of water is not strictly limited, and preferably 0.3 to 10 mass % based on the amount of slurry liquid. When less than 0.3 mass %, no appreciable effect is obtained. When exceeding 10 mass %, the increased amount of vapor phase in the batch-wise polymerization reactor detrimentally affects the fixation of the diamine component. In addition, the foaming and solidification of polyamide are caused during the separation of polyamide and condensation water.
The continuous method for producing polyamide of the present invention comprises a step (1) for preparation of the slurry liquid, a step (2) for amidation and a step (3) for removal of condensation water from polyamide. In the step (2), the diamine component is fixed into polyamide. To maintain the molar balance achieved in the step (1) during the fixation of the diamine component, it is important for the continuous polymerization reactor, into which the slurry liquid is fed, to have a construction capable of minimizing the escape of vapor phase component therefrom and achieving complete vapor-liquid mixing. Therefore, the reaction system is kept at ordinary pressure to about 3 MPa, and the continuous polymerization reactor is preferably made into sealed structure equipped with a gear pump, etc. disposed at a feed opening and/or an outlet. Further, it is important for the continuous polymerization reactor to be capable of gradually raising the temperature of the slurry liquid in the flowing direction within a temperature range from the melting point of polyamide to a temperature of the melting point +10xc2x0 C. For this purpose, a horizontal twin-agitator mixer, etc. is preferably used.
In the step (3), the polymerization degree of polyamide is increased to an intended level. To facilitate the removal of condensation water as vapor from polyamide, the reaction system is kept within a temperature range from the melting point of polyamide to a temperature of the melting point +30xc2x0 C. and kept under a pressure lower than that of the step (2), preferably 0.006 to 0.5 MPa. The step (3) may be carried out using two or more continuous polymerization reactors, and the operating manner and the number of the reactors can be determined according to the desired polymerization degree of polyamide. Alternatively, the polymerization degree of polyamide can be preferably increased by using at least one polymerization reactor maintained at ordinary pressure to a reduced pressure of about 1 kPa after removing a major portion of condensation water generated in the step (2) by a vapor-liquid separation tank disposed downstream the step (2). It is industrially advantageous to recover the diamine component by a partial condenser from the water vapor removed from polyamide, and to recycle the recovered diamine component to the continuous polymerization reactor together with the slurry liquid of the diamine component and the dicarboxylic acid component.
As mentioned above, water catalyzes the formation of nylon salt to induce the evolution of a large quantity of neutralization heat. As a result thereof, water also promotes the amidation reaction. Therefore, it is extremely advantageous for promoting the polymerization to add a small amount of water as the catalyst when the slurry liquid is fed to the continuous polymerization reactor in the step (2). The addition amount of water is not strictly limited, and the slurry liquid is added with water preferably so as to have a water content of 0.3 to 10 mass %. A water content less than 0.3 mass % shows no appreciable effect. A water content exceeding 10 mass % increases the vapor phase in the continuous polymerization reactor to detrimentally affect the fixation of the diamine component, and also causes foaming and solidification of polyamide during the separating operation of polyamide and condensation water.
The removal of the condensation water generated by the amidation reaction from polyamide in the step (3) is preferably carried out after the number average molecular weight of polyamide reaches 1000 or higher, more preferably 2000 or higher. The removal after reaching a molecular weight of 1000 or higher is extremely advantages in controlling the molar balance of polyamide, because the fixation of the polyamide constituting components, particularly the diamine component into polyamide sufficiently proceeds, thereby preventing the escape of the diamine component from the reaction system. The upper limit of the number average molecular weight is not particularly limited.
The process for producing polyamide of the present invention has the following advantages:
(i) The foaming and solidification of polyamide during the removal of a large amount of water is avoided because an aqueous solution of nylon salt is not used as the starting material.
(ii) Since the charged amount of the starting diamine component and dicarboxylic acid component is accurately controlled by the batch-wise mass measuring device, the accuracy of the charged molar balance is improved.
The present invention will be explained in more detail by reference to the following examples which should not be construed to limit the scope of the present invention.
The measurements for evaluations were made by the following methods.
(A) Amount of amino end groups (xcexceq/g)
An accurate amount of polyamide was dissolved in a mixed solvent of phenol/ethanol=4/1 (volume ratio) at 20 to 30xc2x0 C. by stirring. After completely dissolved, the resultant solution was subjected to neutralization titration by 0.1 mol/liter (xe2x80x9cliterxe2x80x9d is hereinafter symbolized as xe2x80x9cLxe2x80x9d) hydrochloric acid, and the amount of amino end groups was calculated from the result.
(B) Amount of carboxyl end groups (xcexceq/g)
An accurate amount of polyamide was dissolved in benzyl alcohol at 160 to 180xc2x0 C. in nitrogen stream by stirring. After completely dissolved, the resultant solution was cooled to 80xc2x0 C. in nitrogen stream and then added with 10 cc of methanol. Then, the solution was subjected to neutralization titration by 0.1 mol/L aqueous solution of sodium hydroxide, and the amount of carboxyl end groups was calculated from the result.
(C) Number average molecular weight
The number average molecular weight was calculated from the following equation using the obtained amount of carboxyl end groups and amount of amino end groups.
Number average molecular weight=2xc3x97106/([NH2]+[COOH]) wherein [NH2] is the amount of amino end groups and [COOH] is the amount of carboxyl end groups.
(D) Water content (mass %)
The water content was determined using a Karl Fischer""s micro-moisture meter (CA-05 Model manufactured by Mitsubishi Chemical Corporation).


A method for the operation of a wind energy plant with a rotor, which transfers a driving moment to a generator via a drive train, wherein the generator provides a pre-settable generator moment acting opposite to the driving moment and is connectable to a grid, characterised in that after a sudden voltage change in the grid, the generator moment is controlled depending from the phase position of a torsional vibration of the drive train.

The present invention is related to a method for the operation of a wind energy plant with a rotor, which transfers a driving moment to a generator via a drive train, wherein the generator provides a pre-settable generator moment acting opposite to the driving moment, and is connectable to a grid.
Such wind energy plants are normally connected to a power supply grid of an electric utility and feed electric power into the power supply grid. In doing so, the wind energy plants provide active power and reactive power, and can perhaps perform a contribution for the stabilisation of the power supply grid.
The demands made by the electric utilities for the wind energy plants are specified in detailed grid connection rules. In this matter, the demands for the behaviour of wind energy plants at voltage dips in the grid have greatly changed in the last years. While in the past, the wind energy plants had to be separated from the grid as fast as possible at a voltage dip, actual grid connection rules prescribe that the wind energy plants must remain connected to the grid at certain voltage dips, in order to support the grid through the supply of reactive power. For instance, the grid connection rules may prescribe that the wind energy plant is not to be separated from the grid at a voltage dip, wherein the voltage remaining in the grid is greater than 15% of the rated voltage and which does not exceed a certain period of time.
However, special protection measures have to be taken in order to avoid a damage or destruction of the electric components of the wind energy plant, when the same remain connected to the grid during sudden changes of the voltage of the grid.
A generator system with a corresponding protection device and a method for the operation of the generator system are known from WO 204/030199 The known generator system has a double-fed three-phase generator with grid-coupled stator coil and at least one rotor coil. In the known method, the current flow in the stator circuit is interrupted through the activation of a fast cut-off unit after the detection of a sudden change of the voltage of the grid. Thereafter, the generator is synchronised with the actual grid voltage again and the current flow between grid and stator is permitted again. Through this measure, an electric overload of the components of the generator system is avoided.
However, when using such a generator system in a wind energy plant, the mechanical stresses occurring during a voltage change must also be taken into account. For instance, most notably sharp changes of the generator moment occur as a consequence of sudden voltage changes, which leads to a high mechanical stress of the elements of the drive train, for instance, in the context of the great lag coefficients of the movable parts of a wind energy plant.
On the basis of this, it is the objective of the present invention to provide a method for the operation of a wind energy plant which reduces those mechanical stresses of the components of the wind energy plant which are due to sudden changes of the grid voltage.

Method for the operation of a wind energy plant at sudden voltage changes in the grid


A dynamic random access memory (DRAM) is selectively operable in a sleep mode and another mode. The DRAM has data storage cells that are refreshed in the refresh mode. A boosted voltage is provided for the operation of the DRAM. A boosted voltage provider includes a group of charge pump circuits that are selectively activated by a pump control circuit based on a refresh time for refreshing data in the DRAM cells in the sleep mode.

Semiconductor memory devices, such as, for example, dynamic random access memory (DRAM) store data in an array of cells with each cell storing one bit of data. The cell arrays are typically arranged in rows and columns such that a particular cell is addressed by specifying its row and column within the array. Cells in a row are connected together to a wordline and cells in a column are connected together to a bitline. Sense amplifiers connected to the detect data in the cells.
Each of DRAM cells includes a storage capacitor. As such, the cells are considered "dynamic", since the stored data (i.e., charged capacitor) will dissipate after a relatively short period of time. In order to retain the stored data, the contents of the DRAM cells are refreshed on a periodic basis by reapplying the charged state of the storage capacitor of each cell in a repetitive manner. A refresh operation is similar to a read operation in that the data in the cells is sensed by the sense amplifiers and the data is rewritten to the cells. Thus, the data is "refreshed" in the cells. The refresh operation is performed by enabling a wordline according to a row address and enabling a sense amplifier. Refresh operations can be either "auto-refresh" performed when the DRAM is in an active mode or "self-refresh" performed when the DRAM is in a sleep mode.
A boost required for getting from an external supply voltage (Vdd) to a gate voltage of access transistor sufficient to charge the capacitors of the cells changes with various characteristics of the DRAM. For example, the amount of current boost required overcoming the voltage dropping when a refresh operation occurs in the sleep mode increases with decreasing refresh time. An internal voltage supply is typically configured without regard to variable refresh times, often relying on a consideration of only the worst possible refresh times. The refresh rate of the DRAM is typically set by the manufacturer to a time period that ensures that data will not be lost. However, this time period may be more frequent than necessary and it may be desirable to reduce this frequency in order to reduce power consumption. The maximum driving capacity of an internal voltage supply is typically determined according to the worst refresh characteristics (i.e., the shortest time period). It, thus, provides more current than is required and results in greater power consumption.
For example, DRAMs in the 0.13 μm to 0.18 μm size range typically have longer refresh time periods (e.g., over 8 ms) and as such the sleep mode current requirements are low. As the size of DRAMs decreases to around 90 nm, MIM (metal-insulator-metal) type capacitors having shorter and more variable refresh time periods are used. A self-refresh pump circuit may not easily handle this variability in the voltage boost and current to be produced. Therefore, the refresh time period may be set according to the shortest possible period. If the DRAM has a higher refresh time period, then it may result in over-pumping and inefficient power use in the sleep mode.

Dynamic random access memory and boosted voltage producer therefor


An adapter for adapting a uniform contact grid of an electrical testing device for testing printed circuit boards to an irregular contact configuration of connection points on a printed circuit board to be tested includes upper and lower pin retention plates respectively defining a cover surface to lie against a surface of the printed circuit board to be tested and a base surface to lie on a contact field of the testing device. Substantially an entire space between the upper and lower pin retention plates are filled with a substantially incompressible solid body of low density and high surface pressure resistance. Needle-like test pins are positioned in test pin channels extending through the solid body.

A present invention relates to an adapter for adapting a uniform contact grid of an electronic testing device for testing PCBs (printed circuit boards) to an irregular contact configuration of contact points on a PCB to be tested.
A "universal adapter" in accordance with EP-B1 26 824 has a base plate lying on a base grid of a testing device, which is provided with channels or bores which pass through it corresponding to a uniform contact grid of the testing device. At a distance above the base grid concerned, that is on a side of the base plate facing away from the base grid of the testing-device, there is an arrangement of two spaced-apart adapter plates, disposed or positioned by fixed spacing means. These adapter plates are identically provided with bores which are distributed corresponding to variably disposed connection points of a PCB to be tested. Needle-like test pins, which are resilient longitudinally, are inserted into these bores in the adapter plates. These test pins are able to pivot resiliently outwards, at least in their lower section, transverse to a lengthwise direction of the test pins, thus to offset any defects of alignment between the testpiece-specific bores and the grid of the testing device connected channels. With such an adapter made up of several plates, a manufacturer of PCBs must prepare at least the testpiece-specific adapter plates for each test series, in order to be able to assemble an adapter at all. Thus, rationalization for production of adapters is, to this extent, not possible.
As many thousands of connection points can be provided in complex PCBs, and a resilient test pin is needed for each connection point, costs for such an adapter rise markedly with increase in the number of contact points, since test pins that are resilient in the longitudinal direction require production costs that are not inconsiderable. In addition, such test pins have a minimum practical diameter that represents a natural limit for the possible density of the test pins.
In order to be able to use test pins that are rigid in the longitudinal direction and that thus are easy to manufacture to be particularly thin, an "active base grid" has been produced in which contacts of the base grid of a PCB testing device are resiliently supported essentially in the direction of the longitudinal axis of the test pins. This active base grid is applied onto the rigid, hard-wired base grid of the PCB testing device and serves, when rigid test pins are used, to provide sufficiently high contact pressure which is as uniform as possible at all test points contacted by the rigid test pins.
EP-A1-0 215 146 shows an adapter ("adapter 85") having an upper testpiece-specific bored adapter plate that lies on a PCB to be tested and rigid contourless test pins that pass through an additional elastic mat disposed at a distance below the PCB. The elastic mat is unbored and, because of the elasticity of material of the mat, prevents falling out of the test pins during handling with the adapter concerned, independently of the actual testing device. In this way, upon subsequent testing of identical PCBs, the labor costs of fitting the adapter with test pins, which costs are not inconsiderable, can be saved. Such adapter can be stored again until it is again used. Such adapter has the advantage that rigid, completely contourless test pins, which can be manufactured very cheaply, can be used, although fitting of the adapter becomes more complicated in that the test pins cannot simply "drop into" the adapter, but rather have to be pushed through the unbored elastic mat with a certain force. This adapter furthermore has an inner adapter plate, a grid of which, however, corresponds neither to the grid of the outer adapter plate or to the grid of the base plate. This therefore means that it is necessary to manufacture at least one further adapter plate with a bore pattern which differs from that of a first-mentioned adapter-plate, in addition to the testpiece-specific bored adapter plate.
There are further adapter-designs for which an entire series of bored adapter plates are disposed between a testpiece-specific bored adapter plate and a grid-hole plate of an adapter lying on a contact point grid of a testing device. Bore patterns of the series of adapter plates produce a gradual transition from the testpiece-specific bored adapter plate to the grid-hole plate and therefore vary in each case and thus require higher production costs and costs for materials when producing such adapters. In addition, fitting such adapters with test pins is particularly difficult.
The adapters described above were designed for one side testing of PCBs. Increasingly however PCBs that have connection points on both sides are being used, and they must be tested on both sides. Two successive one-side tests can be used, although breaks in current due to so-called "risers" then will not be detected, such risers moreover being particularly sensitive to breaks in current. PCB testing devices therefore have been developed which are able to effect simultaneous testing on both sides of PCBs. This then also leads to a need for adapters for such testing devices. Unfortunately, many adapters can be used for simultaneous double-sided testing only in exceptional cases, since if connection points on both sides of a PCB to be tested are unevenly distributed, with the sometimes several thousand test pins there will result substantial deformation or displacement of the test-piece. This can lead to additional (new) defects in the connection paths, or even to breakage of the PCB, particularly with ceramic boards. With one-sided testing of PCBs, uneven distribution or localized concentration of test-pins cannot lead to such a disadvantageous effect, as abutment on the opposite side of a testpiece can be by a stable plate of the actual testing device, and such plate takes up all irregular inputs of force into the PCB, substantially without deformation, and thereby supports the PCB to be tested in a largely undeformed state. With simultaneous, double-sided testing of PCBs, this however is not possible, since rigid abutment either is not present on a second side of a testpiece, or is the testpiece-specific bored adapter-plate of the other adapter, whereby this adapter plate cannot be made to be rigid at will, particularly as it is frequently produced from acrylic glass or similar material, in order to facilitate a manual fitting of the adapter.
The problem of possibly missing abutment and therefore of localized application of excessive force to a PCB during simultaneous, double-sided testing thereof is overcome by an adapter per EP-0 315 707 ("adapter 87") by introducing additional support means into such adapter at particularly loaded points, as separately sprung support-pins for example. With further increasing densities of connection surfaces of PCBs to be tested, occurring as part of the miniaturization of PCBs or wiring carriers, it is becoming more and more difficult to provide the space necessary for these support pins between the actual test pins. In addition, production and insertion of the support pins into an adapter results in substantial additional production costs.
There are adapter arrangements including resilient test pins (U.S. Pat. No. 3,654,585) or flexible elastic bits of wire (EP-184 619) disposed, with comparable function, parallel to each other in an essentially rigid or compressible solid body, that is, a "vertical PCB". However, the actual translation or adapting between irregularly or unevenly disposed testpiece-oriented contact points and the contacts of the testing device in a strictly grid-shaped arrangement is brought about by an additional "transition plate" which in accordance with standard PCB technology is provided with contact surfaces that are offset from each other, on both board surfaces, and with "risers" for connection of the contact surfaces. These adapter arrangements therefore require increased production costs simply due to the requirement for the transition or adapter plate.


Electrostatic clamp structure having a pedestal in which the normal hard insulator surface facing the wafer for a conventional electrostatic clamp is replaced by resilient layer(s) adjacent to the wafer. In this structure the layer(s) adjacent to the wafer permit the xe2x80x9cbumpsxe2x80x9d on the facing wafer surface to xe2x80x9csink intoxe2x80x9d the resilient layer of the chuck so that a substantial part of the bumpy wafer surface is in good thermal contact with the resilient layers. Such resilient layers are bonded to an underlying metal pedestal. These layers are adequate conductors of heat and are in good thermal contact with an underlying pedestal structure which may be actively cooled by conventional means.

This invention pertains generally to the processing of semiconductor wafers and, more particularly, to a clamp for holding workpieces with irregular surfaces.
Typically, workpieces are electrostatically clamped in order to hold them securely and in some cases to facilitate heat transfer between the workpiece and the clamping structure. Such conventional electrostatic clamping structures have flat or smooth curved surfaces conforming to the shape of some part of a workpiece. Typically the surface of such a clamp is hard or firm so that a bumpy surface with irregularities greater than a certain size which were not highly compressible would prevent conformal contact between workpiece and electrostatic clamping structure. Thus interfering with efficient heat transfer between workpiece and clamping structure. The wafers, whether silicon or other materials, on which integrated circuits are fabricated are currently hundreds of microns in thickness. The portable electronic devices (such as cellular phones and smart cards) which use an increasing fraction of semiconductors require that the packaged integrated circuit chips (IC chips or IC""s) be of the same order of thickness or less than that of the original wafer. In order to accomplish such IC packaging these wafers are increasingly being thinned from the backside after the circuits are manufactured on the front side. Such wafer thinning almost always involves grinding away (the most economic method for removing a large amount of wafer material) a good fraction of the wafer material on the back-side thus leaving it reduced in thickness. Such grinding, however, leaves IC""s which have scratches in their back sides, which weaken them. Such scratches are almost always confined to a layer of material within a few tens of microns of the surface left by the grinding. When such chips are mounted to a wiring board to make electronic products the stresses associated with the flexing of the board, or the thermal expansion of the board (when the IC""s are in operation and producing heat) can cause the semiconductor material to break. However, if the wafer material within the scratched and damaged layer is removed by a soft etching method then the strength of the wafer material is restored somewhat and the failure rate of the packaged IC""s is much reduced.
The most economical and safest methods for accomplishing this soft etching of the wafer material are dry etching methods, of which there are many. In many such dry etching methods it is possible to accelerate the rate of etching to levels which make removal of tens of microns of material economic but for all of these it involves generation of substantial amounts of heat on the wafer surface. This heat then needs to be removed in order that the wafer temperature be limited to values which do not melt the solder balls which had been mounted on the device side of the wafer.
Removing such process heat from the device side of the wafers with their attached solder balls is not an easy thing to accomplish. It may be done by use of flowing air or gas at pressures of tens of Torr or higher. However, some of the most efficient etching technologies involve plasmas for producing the etching where the gas pressure for the process is less than or of the order of several Torr. In this case the gas cooling of the wafer is not practical. Further complicating the cooling of such wafers is the fact that it is essential to protect the device side of the wafer where the solder balls are mounted so that no damage to the exposed IC""s is caused by handling such wafers. Such handling includes transporting the wafers into and out of the grinding and etching systems and mounting wafers during both grinding and etching operations. Protecting such vulnerable wafers is usually done with a plastic polymer tape applied to the device side of the wafer whereon the solder balls are mounted. Such tape covers the whole of the device side and is typically between 70 microns and 120 microns in thickness. The layer of adhesive which holds the tape to the wafer is typically of the order of ten microns to a few tens of microns thick. Since the solder balls themselves are often 50 microns to more than 100 microns in height and the plastic tape is only moderately resilient the exposed surface of the tape after covering the wafer is still a little xe2x80x9cbumpyxe2x80x9d. The solder balls simply do not xe2x80x9csink intoxe2x80x9d the tape enough to produce a smooth and level exposed surface by which to handle and clamp the wafer. Typical electrostatic wafer clamping on the taped side of such wafers will not even make effective thermal contact with the raised areas of the plastic tape corresponding to the xe2x80x9cbumpsxe2x80x9d. In order to make such wafer clamping with significant pressure with a roughly 100 micron plasma tape intervening will require much higher clamping voltages than are typically employed. However, clamping in other areas will be ineffective for good heat transfer. Further, there will be stresses induced in the thin wafers by the difference in the clamping pressure at the solder balls and the areas adjacent to the balls which may cause the wafers to break.
In order to effectively and safely clamp such wafers to allow efficient heat transfer from wafer to pedestal it is necessary to use a new type of electrostatic clamp which applies roughly equal clamping pressure to wafer areas corresponding to the xe2x80x9cbumpsxe2x80x9d as well as to other areas. This must be done in such a way that tens of thousands of such wafers can be clamped and then released from clamping without leakage of any adhesive or significant wear or damage to the resilient layers of the clamping structure, or electrical breakdown of any electrical insulating layer.
The basic monopolar electrostatic chuck typically employs a single dielectric insulating layer between a base which may be made electrically charged and a conducting workpiece which is to be held. A simple example of a monopolar chuck is shown in FIG. 1. In this device, a wafer 101 is clamped to a pedestal 103 which may be electrically biased by voltage source 105. A dielectric insulating layer 102 between conducting wafer and pedestal base 103 prevents much charge from flowing to the wafer from the biased pedestal base. An electrical grounding contact 104 serves to allow electric charge to flow to the clamped workpiece to compensate that on the pedestal base and thus confine the largest part of the electrical field to the region between the workpiece and the base. Such an insulating layer may be a multi-layer structure which consists of more than one dielectric. The layers included in this device were intended to be incompressible solid dielectric materials which were not substantially compressible. However, this device was not meant to hold bumpy workpieces.
It is in general an object of the invention to provide a new and improved electrostatic clamp for holding workpieces with irregular surfaces.
Another object of the invention is to provide an electrostatic clamp of the above character which overcomes the limitations and disadvantages of the prior art.
These and other objects are achieved in accordance with the invention by providing an electrostatic clamp structure having a pedestal in which the normal hard insulator surface facing the wafer for a conventional electrostatic clamp is replaced by resilient layer(s) adjacent to the wafer. In this structure the layer(s) adjacent to the wafer permit the xe2x80x9cbumpsxe2x80x9d on the facing wafer surface to xe2x80x9csink intoxe2x80x9d the resilient layer of the chuck so that a substantial part of the bumpy wafer surface is in good thermal contact with the resilient layers. Such resilient layers are bonded to an underlying metal pedestal. These layers are adequate conductors of heat and are in good thermal contact with an underlying pedestal structure which may be actively cooled by conventional means.

Electrostatic clamp for holding workpieces with irregular surfaces


The preferred embodiment provides a method for fabricating field effect transistors that have different threshold voltages without requiring excessive masking and other fabrication steps. In particular, the method facilitates the formation of FETs with different threshold voltages by doping the gate dielectric with various amounts of ions. This provides a built in potential in the gate dielectric proportional to the amount of ions in the gate dielectric. This potential changes the threshold voltage of the FET. Thus, by selectively doping the gate dielectric with ions the threshold voltage of a FET can be changed. The selective doping of many FETs to many different threshold voltages can be done with only one additional masking step. Thus, the present invention provides the ability to form FETs having different threshold voltages without requiring excessive process complexity.

1. TECHNICAL FIELD
The present invention relates generally to the field of semi-conductor manufacturing and, more specifically, to a method for forming field effect transistors with selective threshold voltages.
2. BACKGROUND ART
The need to remain cost and performance competitive in the production of semiconductor devices has caused continually increasing device density in integrated circuits. To facilitate the increase in device density, new technologies are constantly needed to allow the feature size of these semiconductor devices to be reduced.
The push for ever increasing device densities is particularly strong in the design and fabrication of field effect transistors (FETs), such as those used in CMOS technologies. FETs are used in almost all types of integrated circuit design (i.e., microprocessors, memory, etc.) One of the fundamental parameters of the of FET design is the threshold voltage (V.sub.T). The threshold voltage of a FET is defined as the gate voltage required to switch the transistor on or off depending on the type of transistor. In particular, enhancement mode FETs are normally off until a voltage equal to the threshold voltage is applied to the gate, forming a conducting channel under the gate which turns on the FET. By contrast, depletion mode FETs are normally on until a voltage equal to the threshold voltage (usually a negative voltage) is applied to gate which depletes the conductive channel and turns the FET off. In either case the threshold voltage of the FET is a important parameter and significantly controls the behavior of the FET.
Most integrated devices made today include thousands, if not millions of FETs on a single chip. In many cases it is desirable to make the individual FETs on a chip have different threshold voltages such that the different FETs switch at different times. Additionally, it is desirable to be able to change FET's from enhancement mode to depletion mode and vice versa to give additional flexibility to device designers.
The threshold voltage of a FET is determined primarily by the implant dose in the channel and the gate dielectric thickness. Present methods for providing FETs with different threshold voltages on the same chip require a different masking step followed by a specialized channel implant for each different threshold voltage desired. Thus, a chip that requires FETs with five different threshold voltages requires five different masking steps, each followed by a specialized implant of varying dose and energy designed to adjust the threshold voltage. This greatly increases the process complexity with the attending problems, all of which serve to drive chip yield down and costs up.
Thus, there was a need for an improved method for fabricating field effect transistors with varying threshold voltages that does not require excessive masking steps.

Method for forming field effect transistors having different threshold voltages and devices formed thereby

International Business Machines Corporation


A settling system may be used to separate and/or remove solid particles, such as sand, from fluids produced by wells. The container of the settling system may be cleaned without need for manned-entry.

Fluids such as water, oil, and gas exist under pressure in the pores of subterranean reservoir rock formations. Wells are drilled into reservoir rocks to allow fluids (e.g., gaseous and/or liquid hydrocarbons) to flow or to be pumped to the surface of the formation for commercial use. Drag forces created by fluid flow through the reservoir rocks frequently causes particles or small pieces of the reservoir rocks to loosen and flow with the fluids into the well. The loosened rock pieces flow into the well in small particulate form generally referred to as "sand." The sand may vary in size from a few microns to several millimeters in diameter.
Sand-laden fluids flow from reservoir rock into and upward through the casing and tubing of a well. Upon reaching the top of the casing and the tubing of a well, the sand-laden fluids pass through a configuration of control valves known as a well-head. Sand may abrade metal components of the wellhead and/or form restrictions and blockages. Costly intervention methods must be employed to repair the damaged components and/or to remove the sand blockages in the wellhead.
From the well-head, sand-laden fluids enter a flowline, which directs the flow of sand-laden fluids to a separation or other type of processing facility. The flowline often spans a lengthy distance, from a few hundred meters to several thousands of meters, between the well-head and the nearest processing facility. The sand entrained within the fluids can cause abrasion, leaks, and obstructions throughout the span of the flowline, especially where there are abrupt changes in direction and/or elevation of the flowline, often due to the topography of the area. The restrictions, blockages, and/or abrasive damage often occur in remote sections of the flowline that are not readily accessible to vehicles and equipment needed for corrective intervention. Abrasive damage and blockages can also occur at the processing facility, particularly in separators, storage tanks, and/or pumps.
When components of the well are damaged, restricted and/or obstructed by sand, components must be shut-down for repair, which impacts the commercial viability of the well. Because fluids from several wells converge to such facilities, shutting facilities down for repairs requires shutting-in of multiple wells, which adversely impacts the commercial viability of the wells. Separators are used to remove sand and other solid particles from the fluid. However, removing accumulated sand and other solid particles from the separators typically requires manned-entry into such vessels, which poses formidable health and safety hazards, such as possible-entrapment, suffocation, drowning, poisoning, and burning.

Separating sand from fluids produced by a well

Occidental Oil and Gas Holding Corporation


A photopolymerizable adhesive consisting of Compound (1) which contains at least one (meth)acryloxy group as a polymerizing group in its molecule, and other structures constructed from the group(s) selected from the group consisting of alkyl group, alkyloxy group, polyalkoxy group, siloxanyl group and the substituted group thereof substituted by fluorine, hydroxy or alkoxy group; Compound (2) selected from (meth)acrylic acids, hydroxyalkyl (meth)acrylates, (meth)acryloxyalkyl succinic acids, trialkoxyvinyl silanes and .gamma.-(meth)acryloxyalkyl trialkoxy silanes; and Compound (3) selected from hydroxyacetophenones, acetophenones, glyoxy esters and camphorquinones, wherein said adhesive comprises 3 to 60 wt % of the compound (2), and 0.1 to 2 wt % of the Compound (3).

Recently, a photopolymerizable adhesive, which can be polymerized by the irradiation with ultraviolet rays or visible light, is widely used in various fields such as glass processing, electronics, optoelectronics and optics instead of a thermosetting or solvent adhesive such as an epoxide resin adhesive, an acrylic resin adhesive or a synthetic rubber adhesive since the photopolyaerizable adhesive is polymerized in a few seconds to a few minutes and exhibits a practical adhesive property upon being irradiated with ultraviolet ray or visible light.
Conventionally, such photopolymerizable adhesive comprises a photopolymerizable monomer and a photoinitiator. The photopolymerizable monomer generally includes a mixture of a multifunctional (meth)acrylate having a relatively large molecular weight and a high viscosity such as a bisphenol A-modified epoxy dimethacrylate, a urethane-modified di(meth)acrylate or a polyester-modified di(meth)acrylate with a radically polymerizable monomer having a relatively small molecular weight and a low viscosity such as hydroxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isodecyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, N-vinylpyrrolidone or N,N-dimethylacrylamide.
The photoinitiator generally includes benzoin, benzoinalkyl ethers, benzophenone, benzophenone derivatives, benzil, thioxanthone, acetophenones and Michler's ketone.
However, a conventional photopolymerizable adhesive generally has a poor ultraviolet transmittance at a wavelength of 400 nm or less. Consequently, such an adhesive is not suitable for bonding a lens, prism, beam splitter or detecting window of an optical instrument in which a high pressure mercury lamp, a metal halide lamp or a mercury xenon lamp is used as the light source since the light energy from said light source is largely lost due to the absorption by the adhesive layer and is not be efficiently used.
Further, the conventional adhesive layer is colored in yellow or brown resulting in deterioration of its ultraviolet transmittance or is crazed or cracked upon intensive exposure to ultraviolet ray after photopolymerization. Therefore, the conventional adhesive cannot be used in an optical system under ultraviolet rays and is impracticable even for indirect application such as bonding and assembly of an inspection window or reflector in an ultraviolet exposing device or of a protecting cover in an ultraviolet lamp.
In addition, the conventional photopolymerizable adhesive has so poor weather resistance that the adhesive layer is colored in yellow or is crazed upon exposure to the sun light after polymerization and therefore, the conventional photopolymerizable adhesive is also impractical for bonding a window glass or assembling a showcase for outdoor usage.
It is generally believed that photochemical reactions such as oxidation and/or degradation caused by the absorption of light such as ultraviolet rays cause coloring, discoloring or deterioration of the mechanical property of a resin composition such as an adhesive.
Previously, many methods for avoiding such coloring or discoloring were proposed. Such methods include employing compounds having no benzene ring as photopolymerizable monomers and using a specific compound as a photoinitiator.
Another method is the addition of ultraviolet absorbents such as benzotriazole derivatives Or benzophenone derivatives to a photopolymerizable adhesive.
All of the above methods are based on the investigation of principal photochemical reactions of the photopolymerizable monomers, photopolymerizable adhesives or the ultraviolet absorbent. However, no attention was paid to the product of the side reaction of the photopolymerizable monomer with the photoinitiator. Further, substantially no investigation was carried out on the photochemical reaction of the photopolymerizable monomer with the ultraviolet absorbent. Consequently, no photopolymerizable adhesive which can stand intense ultraviolet ray irradiation and long-time exposure to ultraviolet rays has not been obtained. Further, ultraviolet transmittance of a conventional photopolymerizable adhesive containing an ultraviolet absorbent was hardly gained after adhesion.


An ECU for executing serial communication via a transmission line has a driver circuit. The driver circuit includes an integrator for integrating a transmission signal and a power source for generating a current which corresponds to the integrated value of the transmission signal and releasing the current to the transmission line. A terminal circuit for receiving a constant current smaller than a maximum current that the driver circuit can discharge is connected to the transmission line. Since the amount of output current from the driver circuit is gradually changed, the generation of noise in the transmission line can be prevented. Further, since the voltage of the transmission line immediately changes to either a high or low level depending on the amount of output current, accurate data communication can be performed.

1. Field of the Invention
The present invention relates to a data communication device for transmitting and receiving serial data via a transmission line. In particular, the present invention relates to a data communication device for performing data communication between electronic devices mounted on a vehicle or the like.
2. Description of Related Art
Conventional data communication devices for performing data communication between electronic devices prevent the generation of radio-frequency noise at rising and falling edges of a waveform of a transmission signal generated by a driver circuit by adjusting the slope of the signal. However, while data communication devices of this type try to eliminate radio noise by suppressing steep changes in the output voltage waveform from the driver circuit such as during the rising and falling edges of the waveform, noise cannot be fully suppressed when there is stray capacitance in the transmission line. In other words, since noise produced in the transmission line depends on the amount of change in the current per unit time, noise from the transmission line cannot be fully eliminated by only controlling steep changes in the output voltage waveform from the driver circuit because of possible steep changes in the waveform of the current flowing through the transmission line when stray capacitance is present.

Data communication device for implementing accurate data communication


Embodiments include methods and systems to remotely and electronically enhance measurement accuracy and speed of electronic brassiere fitting data. A method according to an embodiment can include receiving a set of current user brassiere data from a remote user computing device, receiving a set of physiological images from the remote user computing device, and receiving brassiere fitting data from one or more data sources. The method can further include filtering the brassiere fitting data responsive to the set of current user brassiere data, and generating a first brassiere size responsive to filtering the brassiere fitting data. The method can further include modifying the first brassiere size responsive to the set of physiological images, and generating a recommended brassiere size responsive to modifying the first brassiere size.

Most women wear brassieres that do not fit properly and are either too large or too small. This problem of poor fit is magnified for mastectomy patients, prosthetics wearers, and other amputees, who often need modified sizes and brassiere shapes for a proper fit. Customized brassieres are not widely accessible, however, and require detailed individual measurements to design.

Method to remotely fit brassieres for prosthetics wearers and mastectomy patients


A carton formed from sheet material for containers such as cans or bottles includes a top wall, a pair of side walls and a bottom wall interconnected to form a tubular structure. A notional strip is defined along the top wall, having notional side edges, and extends between the end edges and has a width less than the distance between the side edges. A pair of hand apertures is defined in the top panel, disposed generally astride the notional strip and generally along the notional side edges. A cut line is formed in the top panel and extends from an end edge of the aperture along one of the notional side edges and curves away therefrom to a termination point, the cut line defining a radius of curvature and an area within the arc of curvature. At least one score line is defined in the top panel and extends from a first point disposed within the radius of curvature generally to an adjacent corner of the top panel.

The present invention relates generally to paperboard cartons for use in packaging articles. It is particularly useful for cartons for packaging containers such as cans or bottles for beverages, although the invention is not limited in this regard. More particularly, the invention relates to a handle for such cartons which is associated with stress-relieving severance lines.
Articles such as cans or bottles for beverages including soft drink, beer, juices and the like are commonly sold in multiple quantities packaged in a paperboard carton. For the convenience of the consumer, the carton is often provided with a handle, which commonly includes as a primary feature one or two slots or other apertures formed in the carton. These slots are commonly formed in a top wall of the carton. The user inserts the hand or fingers into one or both of the slots to lift the carton. Many varieties of handles of this type are known in the art.
Lifting a carton containing beverage cans or bottles introduces considerable stress into the paperboard from which the carton is formed. The region around the slot or slots especially tends to be subject to stress concentration. For this reason, and to prevent tearing of the paperboard and failure of the carton, it is known to design carton handles with various stress-relieving and/or stress-distributing arrangements. This is often accomplished by providing fold lines or slits in the carton wall where the handle slots are provided. An example of this type of stress distributing arrangement may be seen in U.S. Pat. No. 5,307,932.
While such arrangements have experienced considerable success, it has still been difficult to eliminate minor cracks and tears from the handle slot area. While these minor cracks or tears do not ordinarily result in handle failure, consumers may see these as undesirable and may not purchase packages exhibiting such cracks or tears.
What is needed, therefore, is a carton having a carrying handle with an improved stress-relieving arrangement. Such a carton should eliminate or reduce stress-induced tears or fractures, particularly those minor cracks and tears which detract from the carton appearance.


A controller is provided for a gas valve including a movable valve element, a main diaphragm chamber having a main diaphragm therein coupled to the valve element to displace the valve element relative to a valve opening, and a servo-regulator diaphragm for regulating flow of gas that acts against the main diaphragm, to adjust the valve element and vary the flow rate. A stepper motor is configured to move in a stepwise manner to displace the servo-regulator diaphragm to adjust the valve element and gas flow rate. The controller for the stepper motor includes a microprocessor that receives an input signal indicating an operating capacity level, and determines the steps the stepper motor must move to displace the servo-regulator diaphragm to establish a flow rate corresponding to the operating capacity level. The microprocessor generates a signal to move the stepper motor the number of steps to adjust the gas valve.

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
A gas-fired, warm air furnace that operates at two or more gas flow rates is generally referred to as a variable or multistage furnace. Multistage furnaces are frequently selected by homeowners for replacement of existing furnaces because they offer increased performance and comfort. However, in multi-stage or variable heating furnaces, the furnace control is only configured for one-way communication with a gas valve. This typically is in the form of a signal applying a voltage source or a variable current signal to the gas valve. However, such signals are not capable of providing feedback, and may not be compatible with replacement or retrofit of gas valves or other components of the furnace. Accordingly, a need still exists for an improved control of variable stage heating systems.

Control of stepper motor operated gas valve


The present disclosure describes a semiconductor device including a semiconductor substrate and a gate stack disposed on the semiconductor substrate. A first spacer element is disposed on the substrate abutting the first gate stack. A second spacer element is adjacent the first spacer element. A source/raised drain is provided adjacent the gate stack. A conductive feature (e.g., silicide) is disposed on the source/drain and laterally contacts sidewalls of the second spacer element. In an embodiment, a contact directly interfaces with the second spacer element.

As technology nodes shrink, semiconductor devices such as a metal-oxide-semiconductor field-effect transistors (MOSFETs) are scaled down and the number of devices of an integrated circuit (IC) increase. Thus, the spacing between gates structures of the ICs decrease (e.g., the pitch in an array of gates becomes tighter). In a method to form such an IC, a dielectric layer such as an inter-level dielectric (ILD) is formed on the substrate and fills in the regions between adjacent gates. However, when an arrangement of gates becomes denser and has a smaller spacing, the ILD layer often cannot effectively fill in the regions between the adjacent gate structures. For example, voids may be formed in the ILD layer. Furthermore, alignment of contacts to the gate structure and/or other transistor features such as a source/drain region may become more difficult as the devices are scaled down. A via used to form a contact may be offset such that an etching process etches through a source/drain region (e.g., low-dose drain) region. This can induce junction leakage.

Spacer elements for semiconductor device

Taiwan Semiconductor Manufacturing Company, Ltd.