Problems on catalyst production and catalyst performance with respect to conventional 8-oxygen-membered ring micropore-containing crystalline silicoaluminophosphate molecular sieves as non-equilibrium methylamine synthesis catalysts, are resolved. A chabazite type crystalline silicoaluminophosphate molecular sieve having high purity and high crystallinity and having, on a crystal grain surface, an amorphous oxide layer whose Si/Al atomic ratio is greater than that of the whole crystal grain can be stably produced with high yield with the use of a small amount of structure directing agents by the present method characterized in that hydrothermal treatment conducted in the production of 8-oxygen-membered ring micropore-containing crystalline silicoaluminophosphate sieves is controlled under specified treating conditions. The thickness and composition of the amorphous oxide layer, which exert marked influence on the yield of dimethylamine synthesis, can be easily controlled and reproduced under the conditions of catalyst synthesis according to the invention. Thus, the catalyst of high performance can be stably supplied by the present invention at a low cost with reduced output of waste.

Methylamines are generally synthesized from methanol and ammonia at around 400° C. in the presence of a solid acid catalyst, e.g., silica-alumina. As is well known, use of the silica-alumina catalyst leads to predominant production of trimethylamine according to thermodynamic equilibrium although trimethylamine is least demanded among the three types of methylamines, namely, mono-, di- and tri-methylamines. Since dimethylamine accounts for most of the demand for methylamines, methods have been recently developed to selectively produce dimethylamine, overcoming the thermodynamic equilibrium composition.
Some of these methods include those using zeolites (crystalline aluminosilicate molecular sieves), e.g., Zeolite A (see, for example, Patent Document 1), FU-1 (see, for example, Patent Document 2), ZSM-5 (see, for example, Patent Document 3), ferrierite and erionite (see, for example, Patent Document 4), ZK-5, Rho, chabazite and erionite (see, for example, Patent Document 5) and mordenite (see, for example, Patent Documents 6, 7, 8 and 9).
These methods deal with zeolites small in micropore channel size, and try to improve selectivity for dimethylamine and catalytic activity by subjecting them to ion exchanging, dealumination, doping with a specific element or silylation in order to control micropore channel size or modify acid sites on external surfaces thereof.
Also known is a method for production of monomethylamine or the like at a higher proportion than the thermodynamically equilibrium composition by use of a crystalline silicoaluminophosphate molecular sieve (hereinafter referred to as SAPO in principle) as a non-zeolitic molecular sieve (see, for example, Patent Document 10).
After having extensively studied selective dimethylamine production techniques, the inventors of the present invention have also found that SAPOs modified with silica or other various oxides exhibit higher activity and dimethylamine selectivity than conventional zeolite catalysts, and have already applied for patents (see, for example, Patent Documents 11, 12 and 13).
It is generally considered that crystalline molecular sieves, e.g., zeolites and SAPOs, have a surface consisting of an exposed crystal lattice surface. Therefore, the surface of zeolites and SAPOs has strong acid sites which are characteristic of molecular sieves that contain silicon and aluminum. In order to improve selectivity for dimethylamine production, the surface acid sites are often subjected to chemical vapor deposition using silicon compounds, liquid-phase silylation, modification with a boron- or phosphorus-containing compound, or the like (see, for example, Patent Documents 14, 15, 16, 17 and 18). The techniques already described by the present inventors in the patent publications (see Patent Documents 11, 12 and 13) are also based on these concepts.
However, these conventional processes require lots of steps since they require separation and washing by centrifugation or filtration after synthesis of SAPOs and, in some cases, further modification of calcined catalysts. In particular, silylation needs precise control of moisture content of catalysts to be treated, and uses organic solvents, e.g., ethanol or toluene, thereby causing problems of disposal of waste fluid.
In this way, these conventional processes, in which synthesized SAPOs are further modified to improve activity and selectivity, involve problems to be solved both economically and environmentally. There are demands for development of new methods which can control activity and selectivity during steps for synthesis of SAPOs and thus differently from the conventional processes that require the post-treatment steps.
In order to solve these problems, the present inventors have already found that an 8-membered ring SAPO of chabazite structure having a rectangular parallelepiped or cubic crystal form of 5 μm or less in average grain diameter works as an excellent methylamine production catalyst of high activity and dimethylamine selectivity, and have already applied for patent (see Patent Document 19), in addition to the above-described techniques.
This 8-membered ring SAPO of chabazite structure exhibits excellent activity and selectivity without modification after synthesis. However, the present inventors have further studied it and observed a phenomenon of catalyst performance depending upon some synthesis lots. Therefore, it involves technical problems that must be further improved to obtain an optimum catalyst stably.
The 8-membered ring SAPO of chabazite structure having the above-described particle size and shape is synthesized using organic amines or organic ammonium salts, e.g., diethanolamine or tetraethyl ammonium hydroxide in an amount of 1.5±0.5 times the mole number of the aluminum compounds as Al2O3. On the other hand, the amount of the organic amine or organic ammonium salt incorporated into the 8-membered ring SAPO of chabazite structure just after synthesized but before calcined is an amount required to establish the crystalline structure, namely, only about 0.37 times the mole number as Al2O3. The surplus organic amines or organic ammonium salts, which are not incorporated into the crystalline structure, should be treated by activated sludge or the like. Therefore, synthesis of a pure 8-membered ring SAPO with a reduced amount of organic amines or organic ammonium salts would be a desirable process both economically and environmentally.
Since 8-membered ring SAPOs exhibit relatively high selectivity for dimethylamine in methylamine synthesis, various studies have conventionally been made on the synthesis of methylamines using such SAPOs (see, for example, Non-patent Document 4). As 8-membered ring SAPOs, are known SAPO-14, -17, -18, -33, -34, -35, -39, -42, -43, -44, -47 and -56 (see, for example, Non-patent Documents 5 and 6). Among them, three types, namely, SAPO-34, SAPO-44 and SAPO-47 are known to have the chabazite structure. In particular, the SAPO-34 of chabazite structure has been extensively studied as a catalyst for methylamine synthesis and methanol conversion (see, for example, Patent Documents 10 and 21).
It is known that these 8-membered ring SAPOs can be synthesized by hydrothermally treating a mixture of a silicon compound, aluminum compound, phosphorus compound and water in the presence of a structure directing agent such as tetraethyl ammonium hydroxide, morpholine, cyclohexylamine and diethylethanolamine (see, for example, Patent Document 20). It is not known, however, that these 8-membered ring SAPOs have an amorphous oxide layer on their crystal grain surfaces, and the amorphous oxide layer grows on crystal grain surfaces during the hydrothermal synthesis and has a great effect on yield and selectivity of the methylamine synthesis.
In general, the mixture to be hydrothermally treated to synthesize 8-membered ring SAPOs is represented by the compositional formula (1) shown below, and the structure directing agent R is used in an amount of 1 to 3 times the mole number of Al2O3 in the mixture (a/c=1 to 3):aR, bSiO2, cAl2O3, dP2O5, eH2O  Formula (1)
Survey of the amount of structure directing agents used for synthesis of 8-membered ring SAPOs on various patent documents and literatures reveals that structure directing agents are used in an amount of at least one times the mole number of Al2O3 in the mixture to be hydrothermally treated, in order to produce 8-membered ring SAPOs of chabazite structure with high purity and high degree of crystallinity, and it is mentioned that, when they are used in a smaller amount, there occur impurities, e.g., a SAPO-5 structure which falls under the AFI structure according to the IUPAC structural code specified by the International Zeolite Association (IZA), as well as cristobalite or berlinite of aluminum phosphates.
A literature describes synthesis of SAPO-34 using tetraethyl ammonium hydroxide (TEAOH) as a structure directing agent (see, for example, Non-patent Document 1), and discusses that pure SAPO-34 is produced at a TEAOH/Al2O3 molar ratio of 2 to 3, SAPO-5 is produced at a ratio of 1 to 2, and a high-density phase is produced at a ratio below 1. It is also mentioned that grains having a non-crystalline amorphous structure are produced at a ratio above 3.
A literature describes synthesis of SAPO-34 using morpholine as a structure directing agent (see, for example, Non-patent Document 2), and discusses that a mixture of aluminum phosphate cristobalite and an amorphous compound is produced at a morpholine/Al2O3 molar ratio of 0.5 or less, a mixture of 80% SAPO-34 and 20% cristobalite is obtained at a morpholine/Al2O3 molar ratio of 1.0, and pure SAPO-34 is obtained at a morpholine/Al2O3 molar ratio of 2.0 or more.
In addition, a literature describes synthesis of SAPO-44 using cyclohexylamine as a structure directing agent (see, for example, Non-patent Document 3), and discusses that contamination with SAPO-5 occurs at a cyclohexylamine/Al2O3 molar ratio of 1.9 or less.
The above-cited references are as follows:
Patent Document 1: Japanese Patent Laid-Open No. S56-69846A,
Patent Document 2: Japanese Patent Laid-Open No. S54-148708A,
Patent Document 3: U.S. Pat. No. 4,082,805 specification,
Patent Document 4: Japanese Patent Laid-Open No. S56-113747A,
Patent Document 5: Japanese Patent Laid-Open No. S61-254256A,                Patent Document 6: Japanese Patent Laid-Open No. S56-46846A,
Patent Document 7: Japanese Patent Laid-Open No. S58-49340A,
Patent Document 8: Japanese Patent Laid-Open No. S59-210050A,
Patent Document 9: Japanese Patent Laid-Open No. A59-227841A,
Patent Document 10: Japanese Patent Laid-Open No. H02-734A,
Patent Document 11: Japanese Patent Laid-Open No. H11-35527A,
Patent Document 12: Japanese Patent Laid-Open No. H11-239729A,
Patent Document 13: Japanese Patent Laid-Open No. 2000-5604A,
Patent Document 14: Japanese Patent Laid-Open No. H03-262540A,
Patent Document 15: Japanese Patent Laid-Open No. H 11-508901A,
Patent Document 16: Japanese Patent Laid-Open No. H06-179640A,
Patent Document 17: Japanese Patent Laid-Open No. H07-2740A,
Patent Document 18: Japanese Patent Laid-Open No. S61-254256A,
Patent Document 19: Japanese Patent Laid-Open No. 2000-117114A,
Patent Document 20: U.S. Pat. No. 4,440,871 specification,
Patent Document 21: U.S. Pat. No. 5,126,308 specification,
Non-Patent Document 1: J. Liang, H. Li, S. Zhao, W. Guo, R. Wang, and M. Ying, Appl. Catal., 1991, 64, pp. 31 to 40,
Non-Patent Document 2: A. M. Prakash, S. Unnikrishnan, J. Chem. Soc. Faraday Trans., 1994, 90 (15), pp. 2291 to 2296,
Non-Patent Document 3: S. Ashtekar, S. V. V. Chilukuri, D. K. Chakrabarty, J. Phys. Chem., 1994, 98, pp. 4878 to 4883,
Non-Patent Document 4: D. R. Corbin, S. Schwarz, and G. C. Sonnichsen, Catalysis Today, 1997, 37, pp. 71 to 102,
Non-Patent Document 5: E. M. Flanigen, B. M. Lok, R. L. Patton, and S. T. Wilson, New Developments in Zeolite Science and Technology, Elsevier, 1986, pp. 103 to 112, and
Non-Patent Document 6: Structure Commission of the International Zeolite Association, Atlas of Zeolite Framework Types, Elsevier, 2001, pp. 14 to 15.
As described above, the present inventors have found that, among the SAPOs, an 8-membered ring SAPO of chabazite structure having a rectangular parallelepiped or cubic crystal form of 5 μm or less in average grain diameter works as an excellent methylamine production catalyst high in activity and dimethylamine selectivity without any modification after synthesis, and have already applied for patent (Japanese Patent Laid-Open No. 2000-117114A). However, it has been observed that the SAPO having the above grain diameter and shape still shows variation of catalyst performance depending upon production lots.
The above-described 8-membered ring SAPO of chabazite structure is obtained by hydrothermally treating a starting mixture that contains organic amines or organic ammonium salts such as tetraethyl ammonium hydroxide (TEAOH) and diethanolamine in an amount of 1.5±0.5 times the mole number of aluminum compounds as Al2O3. However, such a method as described above, in which an excessive amount of organic amines or ammonium salts is required, produces the catalyst at a low yield and needs treatment of the surplus organic amines or ammonium salts by activated sludge or the like.
Therefore, the SAPO disclosed in Japanese Patent Laid-Open No. 2000-117114A involves problems that must be further improved concerning catalytic stability for amine synthesis, the excess amount of structure directing agents, or the like.
Objects of the present invention are to solve the above problems and provide an 8-membered ring SAPO having excellent catalytic activity and dimethylamine selectivity, a method for stably producing the SAPO at a low cost, and a method for producing methylamines in the presence of the SAPO as a catalyst.

Crystalline silicoaluminophosphate salt molecular sieve having octaoxygen-membered ring pore, process for producing the same and process for producing methylamine with the molecular sieve as catalyst


A vertically oriented thin film transistor (TFT) having a tunnel barrier is disclosed. The tunnel barrier may be formed from a dielectric such as silicon oxide or hafnium oxide. The vertically oriented TFT selection device with tunnel barrier may serve as a selection device in a 3D memory array. The vertically oriented TFT may be used to connect/disconnect a global bit line to/from a vertical bit line in a 3D memory array. The vertically oriented TFT may be used to connect/disconnect a source line to/from a channel of a vertical NAND string in a 3D memory array. A vertical TFT with tunnel barrier has a high breakdown voltage, low leakage current, and high on current. The tunnel barrier can be at the top junction or bottom junction of the TFT.

The present disclosure relates to technology for non-volatile storage.
Semiconductor memory has become more popular for use in various electronic devices. For example, non-volatile semiconductor memory is used in personal navigation devices, cellular telephones, digital cameras, personal digital assistants, mobile computing devices, non-mobile computing devices and other devices. Electrical Erasable Programmable Read Only Memory (EEPROM) and flash memory are among the most popular non-volatile semiconductor memories.
Some EEPROMs or flash memory devices have a configuration referred to as a NAND configuration in which memory cells are grouped as NAND strings with each NAND string associated with a bit line. One type of NAND memory array is a two-dimensional array. Another type of NAND memory array is a three-dimensional array. One 3D NAND stacked memory device is sometimes referred to as a Bit Cost Scalable (BiCS) architecture.
In a 3D NAND BiCS architecture, a 3D NAND stacked memory device can be formed from an array of alternating conductor and insulator layers. A memory hole is drilled in the layers to define many memory layers simultaneously. A NAND string is then formed by filling the memory hole with appropriate materials. A straight NAND string extends in one memory hole, while a pipe- or U-shaped NAND string (P-BiCS) includes a pair of vertical columns of memory cells which extend in two memory holes and which are joined by a pipe connection. Control gates of the memory cells are provided by the conductor layers.
Another example of non-volatile memory uses variable resistance memory elements that may be set to either low or high resistance states. Upon application of sufficient voltage, current, or other stimulus, the variable resistance memory element switches to a stable low-resistance state, which is sometimes referred to as SETTING the device. This resistivity-switching is reversible such that subsequent application of an appropriate voltage, current, or other stimulus can serve to return the reversible resistivity-switching material to a stable high-resistance state, which is sometimes referred to as RESETTING the device. This conversion can be repeated many times.
The variable resistance memory elements may be in a high resistance state when first manufactured. This may be referred to as the "virgin state." In the virgin state, the resistance could be even higher than for the RESET state. The term "FORMING" is sometimes used to describe putting the variable resistance memory elements into a lower resistance state for the first time. For some memory elements, the FORMING operation requires a higher voltage than the SET and/or RESET operations.
3D memory arrays having variable resistance memory elements have been proposed.
In one possible architecture, word lines extend horizontally and bit lines extend vertically. There a multiple levels of the word lines, hence multiple levels of memory elements. Each memory element is located between one of the vertical bit lines and one of the horizontal word lines. During operation, some of the memory cells are selected for the SET, RESET, or FORM operation, while others are unselected.


The present invention relates to multi-ribozymes and their use to target RNA in a tissue-specific, target RNA-specific, or pathogen-specific manner for the treatment of cancers, proliferative disease, and bacterial, parasitic and viral infections. More specifically, the present invention relates to the use of virions and viral vectors to package and deliver DNA encoding the multi-ribozymes to a host. The present invention relates to the use of liposomes and lipid-DNA complexes to deliver DNA encoding ribozymes to a host. Most specifically, the invention relates to the use of target specific virions to package and deliver DNA comprising a target specific promoter and encoding a ribozyme(s) directed to the target organism nucleic acids. The present invention further relates to a novel vectors encoding a multi-ribozyme structure with enhanced 5′ and/or 3′ autocatalytically cleaving ribozymes. The invention further relates to nucleotides encoding a multi-ribozyme comprising one or more ribozyme cassettes which contain one or more trans-acting ribozymes and one or more autocatalytically cleaving ribozyme sequences.

2.1 Ribozymes
A ribozyme is a catalytic RNA molecule that cleaves RNA in a sequence specific manner. The use of ribozymes as potential gene regulators in mammalian cells and antiviral agents has been suggested, but subject to serious questions regarding technical feasibility. For example, there are differences regarding how ribozymes can be introduced to target cells or how they can be directed to the same subcellular compartments as their target RNAs. Other questions concern the effects of target RNA secondary structure on ribozyme activity. The art has not been successful in definitively answering any of these questions.
Furthermore, because riboozymes are a form of antisense technology, the problems encountered in applying antisense technology to disease treatment are also encountered in the use of ribozyme technology (Haseloff, J., and W. L. Gerlach, 1988, Nature 334(6183):585-91; Sullivan, S. M., 1994, J. Invest Dermatol. 103(5 Supl):858-895). For example, it has been shown that the expression of antisense RNA in transgenic mice did not invariably lead to a reduction in target RNA molecules, and when reduction in target RNA molecules did occur, it was not predictably paralleled by a reduction in protein. Even when protein levels were reduced sometimes no biological effect was detected (Whitton, J. Lindsay "Antisense Treatment of Viral Infection" Adv. in Virus Res. Vol. 44, 1994).
The experience in the art suggests that it is also not clear whether ribozymes work best when free or when associated with only short non-specific flanking sequences, or when embedded in unrelated larger RNA molecule (Whitton, 1994, supra). At present, sufficient data are not available, either in vitro or in cell culture to allow systematic comparison of the transactivities of free ribozymes with their embedded equivalents.
There have been some studies that focus on the potential use of ribozyme technology in the treatment of cancer. In these studies, ribozymes have been directed against both c-fos and c-ras oncogenes in cell culture, and these showed some suppression of the malignant potential of transfected cells when transplanted into mice. Nevertheless, these ribozymes specifically target an oncogene.
There has been no suggestion in the literature that tissue-specific cancers or other tissue-specific disease can be treated by delivering to that tissue a ribozyme having a tissue-specific promoter, and that it is targeted to an RNA that is essential for cell survival. The invention provides such a ribozyme capable of treating tissue-specific cancers and other tissue-specific diseases.
2.2 Promoters
Furthermore, endogenous delivery of a ribozyme under the control of a tissue-specific or other promoter can be complicated by "leakiness", where low levels of transcription occur in extraneous tissues. This could present a considerable therapeutic problem, depending upon the cellular target chosen. The present invention compensates for this problem by targeting a cellular target which is associated with high levels of product (such as, RNA polymerase I produces large amounts of cellular ribosomal RNA). Thus, in the event promoter leakiness occurs in unintended tissues, it is not likely that cell death would occur. This choice, therefore, provides a needed level of safety, and targeting of pol I would be applicable to many selected tissues using other promoters.
2.3 Delivery
Another common problem in gene therapy is the difficulty in delivering the ribozyme to the correct tissue. The present invention avoids this difficulty by targeting the ribozyme to non-cellular RNAs in cells to which ribozyme constructs can be efficiently delivered. IV liposome delivery will be effective for treatment of HBV hepatitis. Intravenous and/or extracorporeal treatment will effectively delivery construct to erythrocytes for treatment of malarial infection. And topical (with or without iv) administration will effectively deliver ribozyme construct to cervical epithelium in dysplastic/precancerous/cancerous HPV 16 cervical lesions. This latter example is of extreme importance for treatment of dysplastic/carcinoma in situ lesions diagnosed via abnormal Pap smears. A second advantageous facet of the non-cellular target ribozymes of the present invention is that even if promoter leakiness and/or extraneous delivery and/or expression of the ribozyme occurs in unintended cells, the ribozymes should not cleave the cellular RNAs.
2.4 Antimicrobial Agents
Infectious diseases sicken or kill millions of people each year. Numerous antimicrobial therapies have been designed to target one or several infectious agents. These therapies show varying degrees of success in eradicating infection. However, the failure of many of these therapies to target specific infectious agents has lead to overuse or inappropriate use of the therapies, which in turn has lead to the development of drug resistant microbes. The development of drug resistance in many infectious agents has reduced the efficacy and increased the risk of using the traditional antimicrobial therapies.
While ribozymes have been known and studied for several years, they have not been used in the treatment of bacterial infections. There are many reasons for this. A key technical concern in the use of ribozymes as antimicrobial agents is that the ribozyme must be taken up and expressed by the targeted microbe so that the ribozyme(s) can cleave the targeted RNA(s) inside the microorganism. A second important concern is the tight coupling of transcription and translation in microorganisms which can complicate efficient cleavage of targeted bacterial RNAs. These concerns are addressed by the present invention.

Tissue-specific and target RNA-specific ribozymes

MUSC Foundation for Research Development


Convolutional networks can be defined by a set of layers being respectively made up by a two-dimensional lattice of neurons. Each layer—with the exception of the last layer—represents a source layer for respectively following target layer. A plurality of neurons of a source layer called a source sub-area respectively share the identical connectivity weight matrix type. Each connectivity weight matrix type is represented by a scalar product of an encoding filter and a decoding filter. For each source layer a source reconstruction image is calculated on the basis of the corresponding encoding filters and the activities of the corresponding source sub-area. For each connectivity weight matrix type, each target sub-area and each target layer the input of the target layer is calculated as a convolution of the source reconstruction image and the decoding filter. For each target layer the activities are calculated by using the non-linear local response function of the neurons of the target layer and the calculated input of the target layer.

A plurality of problems are usually encountered when dealing with biologically realistic connectionist networks. First, in case connections are not learned statistically, they have to be defined holistically as connecting two points in some high-dimensional neuronal feature space, which is an almost impossible task. Second, due the high dimensionality it is difficult to interpret and visualize the internal states of a network during simulations. Furthermore, the simulation (both memory and performance) of such networks are mainly determined by the number of connections.
The present invention particularly targets at convolutional networks, i.e. having layers with sub-areas, wherein neurons of a sub-area of a layer of the network share a common connectivity weight matrix. The main problems encountered with convolutional networks are the extensive calculation of the dynamics using the shared connections, the non-intuitive design of the connection patterns and the difficult handling of the results. Local dynamic normalization procedures further increase the computational overhead. Finally, a visualization of the network state (i.e. its activity) occurs in a multi-dimensional space.

Simulation of convolutional network behavior and visualizing internal states of a network


A system and method are disclosed for providing a transmission capacity on a data transmission path, wherein such data transmission capacity is provided with regard to a user on a transmission path by using at least one limiting unit.

The present invention relates to a system and an associated method for providing data transmission capacity on a data transmission path which is arranged between at least one transmitting unit and at least one receiving unit.
Telecommunications landline network operators with their own transmission media, such as glass fiber cables, do not always use all the transmission media, particularly transmission lines, which are available for them. Unused transmission capacities in glass fibers can then, for example, be rented to third parties. For example, a transmission capacity of 1.6 Tbit/s can be achieved in monomode fibers on a glass fiber transmission path, which is also referred to as a dark fiber in the following text, which is not terminated by transmission devices.
The present invention is, therefore, directed toward a system and a method to prevent the misuse of free data transmission capacities in a transmission medium.

System and method for limiting the transmission capacity on a data transmission path


A high voltage semiconductor device is provided, comprising a high voltage metal-oxide-semiconductor transistor (HVMOS), and a normally-on low voltage metal-oxide-semiconductor transistor (LVMOS) electrically connected to the HVMOS. The HVMOS has a first collector and a first emitter, and the LVMOS has a second collector and a second emitter, wherein the second collector of the LVMOS is electrically connected to the first emitter of the HVMOS. The LVMOS electrically connected to the HVMOS provides an electro-static discharge bipolar transistor (ESD BJT), such as a NPN-type ESD BJT.

1. Field of the Invention
The disclosure relates in general to a high voltage semiconductor device and a method for manufacturing the same, and more particularly to a high voltage semiconductor device with ESD protection and a method for manufacturing the same.
2. Description of the Related Art
With the development of semiconductor technology, the bipolar COMS DMOS (BCD) manufacturing technology has been widely used for high voltage semiconductor devices. An operating voltage of a semiconductor device for the BCD manufacturing technology has been increased, and therefore an on-chip electro-static discharge (ESD) protection design becomes a challenging task.
A high voltage semiconductor device usually has low on-state resistance (Rdson), so that an electro-static current is likely to concentrate in a surface or an edge of a drain during an electro-static event. High voltage current and high electric field will cause a physical destruction at a surface junction region. Based on a requirement for lowering the on-state resistance (Rdson), the surface or a lateral side of the high voltage semiconductor device cannot be increased. Therefore, it is a challenge to get a better ESD protection structure.
Also, a breakdown voltage of the high voltage semiconductor device is always greater than the operation voltage thereof. A trigger voltage of the high voltage semiconductor device is often higher than the breakdown voltage thereof quite a lot. Therefore, a protected device or an internal circuit usually has risks of damages during the electro-static event, before an ESD protection of the high voltage semiconductor device is turned on. To reduce the trigger voltage, it is usually required to construct an additional external ESD detection circuit.
Moreover, the high voltage semiconductor element usually has a low holding voltage. There is a possibility that the high voltage semiconductor device is triggered by an unwanted noise, a power-on peak voltage or a serge voltage and a latch-up may occur during the normal operation.
Furthermore, the high voltage semiconductor device usually has a field plate effect. The distribution of the electric field is sensitive, so the electro-static current is easy to concentrate at the surface or the edge of the drain during the electro-static event.
Other methods have been proposed for the ESD protection; however, those methods would require additional masks or manufacturing steps. One of the conventional methods for ESD protection is to add an additional device used for ESD protection only. The additional ESD device is a big size diode, a bipolar transistor (BJT), a metal oxide semiconductor transistor (MOS) being increased the surface or the lateral side, or a silicon controlled rectifier (SCR). The silicon controlled rectifier (SCR) has a low holding voltage, so the latch-up may easily occur during the normal operation.

High voltage semiconductor device and method for manufacturing the same


A method for managing resources of a processor device configured to control an automation installation includes using at least one first operating system and at least one second operating system, which preferably differs from the first operating system, to operate the processor device. The processor device includes at least two processor cores configured to operate the operating systems. The method further includes using at least one processor core to operate each operating system and freely selecting a number of processor cores used to operate the first operating system and a number of processor cores used to operate the second operating system.

The present disclosure relates to automation installations and to methods for controlling the latter. Modern automation installations usually have so-called hypervisors, that is to say management systems which manage, for instance, processor powers for the different requirements. Furthermore, such processor devices often have multicore processor systems, that is to say systems having a plurality of processor cores. In this case, these hypervisors usually statically define how many processor cores (also referred to as "cores" below) are available to the individual operating systems of this processor device. Such systems are extensively described in specialist journals. However, such static solutions often do not meet the customer requirements.
In this case, the abovementioned hypervisors usually combine two or more operating systems on one item of multicore hardware. The hypervisor ensures that the respective hardware resources are separated or virtualized.
Therefore, the present disclosure is based on the object of making resource distribution of the available hardware more flexible. This object is achieved by the subject matters of the independent claims. The subclaims relate to advantageous embodiments and developments.

Resource management system for automation installations


The present invention relates to biodegradable polymer compositions comprising poly(lactic acid) and poly(epsilon caprolactone) and co-polyester polymer with adipic acid mixed with organic peroxide and magnesium silicate minerals. In addition, the present invention relates to films, coatings and products made on the basis of said compositions and to a method for their preparation.

Packaging material and disposable beakers, cups and cutlery are used nowadays widely and allow that food material may be sold and/or consumed under hygienic conditions. Such disposable materials and objects are highly estimated by the consumers and the retailers, since they may be simply disposed after use and do not have to be washed and cleaned like conventional dishes, glasses or cutlery.
Yet, the widespread and even growing use of such materials result in a mounting amount of litter produced each day. Currently, the plastic waste is either provided to garbage incinerators or accumulates in refuse dumps, with both of the above-mentioned solutions for waste disposal being associated with problems for the environment.
In addition, paper and composite materials are often provided with a coating, such as e.g. polymeric or wax coatings, for increasing the strength of the paper stock or of the basis composite material, imparting water resistance, enhancing gloss, improving barrier properties, etc. These polymeric or wax coatings give however rise to various problems when articles comprising polymeric or wax coatings are subjected to recycling or re-pulping processes.
Thus, there is a need in the art to obviate the above problem and to provide materials, which combine the advantages of currently used plastics material, do not add to environmental pollution and assist to simplify recycling or repulping processes.
Several Biodegradable polymers are already known in the state of the art and comprise materials e.g. on the basis of poly(glycolic acid), poly(epsilon-caprolactone), poly(lactic acid), and polydioxanone. These polymers require however rather complicated production steps and are rather cost-intensive and therefore currently mainly restricted to high value medical applications requiring bioabsorbable materials.
An object of the present invention is thus to provide a composition, which composition is degraded under normal environmental conditions such as composting including humidity and/or water, air, light, and/or soil bacteria in a controlled time period which is significantly shorter than the time period required for the degradation of conventional plastic materials, such as e.g. polyethylene.
Additionally, such a composition should provide properties for the resulting material required for the respective applications, such as e.g. for the production of articles, films, and coatings. Furthermore, such a composition should be producible at low costs and should be appropriate for a production of objets comprising said composition in large numbers. In addition, such a composition should allow to be processed by means of devices and methods of the state of the art. Moreover, such a composition should provide the possibility to be at least partially producible from renewable resources. When applied as a film or a coating on paper or on a composite material, such a composition should provide degradation properties facilitating a re-pulping or recycling of said paper or composite materials.
These and other objectives will become apparent from the subsequent detailed description of the present invention, which provides a Biodegradable composition, comprising between 40 and 85% by weight of poly(lactic acid), and between 10 and 40% by weight of poly(epsilon caprolactone), each on the basis of the total weight of the Biodegradable composition.

This patent is subject to a terminal disclaimer.

Biodegradable poly(lactic acid) polymer composition and films, coatings and products comprising Biodegradable poly(lactic acid) polymer compositions


A backlight unit according to the embodiment comprises an LED module comprising an LED; a case supporting the LED module; a fixing part fixing the LED module to the case; a reflective sheet comprising an opening for exposing the LED on the LED module and the fixing part; and a guide pin fixing the reflective sheet to the case.

FIG. 1 is a view schematically showing a conventional backlight unit.
As shown in FIG. 1, the conventional backlight unit comprises an LED module 10, a case 20, a fixing part 30 and a reflective sheet 40.
The LED module 10 comprises a printed circuit board 11, an LED 13 formed on the printed circuit board 11, and a mold part 15 formed on the LED 13.
The reflective sheet 40 reflects light, which is emitted from the LED 13, in the upward direction. The reflective sheet 40 is formed with an opening for exposing the LED 13. The reflective sheet 40 has reflectivity of 98% or more.
The fixing part 30 fixes the reflective sheet 40 and the LED module 10 to the case 20. The case 20 may be a cover bottom. An upper portion of the fixing part 30 is exposed on the reflective sheet 40. For instance, the fixing part 30 comprises a screw. In general, the fixing part 30 has reflectivity of about 60 to 70%.
Since there is a difference in reflectivity between the reflective sheet 40 and the fixing part 30, the conventional backlight unit represents non-uniform brightness distribution as shown in FIG. 2. FIG. 2 is a view showing a problem of the conventional backlight unit.
An optical sheet 70, such as a diffusion sheet, can be aligned on the backlight unit. Since the fixing part 30 has relatively low reflectivity, brightness of a region where the fixing part 30 is positioned may be lowered relative to other regions. Thus, a dark line may occur in the region where the fixing part 30 is positioned, causing non-uniform brightness distribution.

Backlight unit and dislay device having the same


A method of mounting elements inside a wind generator tower which is made from various different sections of metal. Elements such as ladders, platforms, and electric cables are fixed to auxiliary supports such as beams or rings which are in turn fixed to the above-mentioned sections so as not to reduce the fatigue strength thereof.

Development and innovation in the wind generator field during recent decades has resulted in the increase of the size and power of the turbines of the same, that entails an increase in the height of the towers, which, in order to be resistant, must have thicker walls. These thicknesses are optimised using a structural calculation of the minimum tower wall thickness capable of safely supporting the loads and the vibrations to which said tower is subjected.
Wind generator towers must hold various different elements inside, including a ladder to enable different maintenance operations to be performed on said elements. In known techniques, these ladders are screwed to guides which, in turn, are joined to connecting parts welded to the inside surface of the tower. For example, document WO0238953 describes some ladders screwed to some bolts that belong to platforms which, in turn, are welded to the inside of the wind generator tower.
Fixtures of this type oblige the thickness of the tower walls to be increased due to a reduced fatigue strength of the same. The present invention proposes a new method for mounting elements in wind generator tower which resolves that problem.

Method of mounting elements inside a wind generator tower


A reference voltage generating apparatus and a driving method therefor are provided. The method of driving the reference voltage generating apparatus for supplying a reference voltage to read data from a ferroelectric memory cell including a ferroelectric capacitor and an access transistor comprises: re-storing, in a reference cell, data equal to data stored in the reference cell, in response to a first control signal, and generating a reference voltage, in the re-stored reference cell, in response to a second control signal, to compare the reference voltage with a voltage corresponding to data stored in the ferroelectric memory cell and to read the data stored in the ferroelectric memory cell. The reference cell includes a ferroelectric capacitor and an access transistor.

An apparatus capable of using a large amount of memory has been pursued to overcome a refresh limit for a DRAM (Dynamic Random Access Memory). Such an apparatus, for example, a ferroelectric random access memory (FRAM), has been developed by applying a ferroelectric thin layer to a dielectric layer of a capacitor. The FRAM, which uses a ferroelectric thin layer, is a nonvolatile memory device that retains storage information when power is interrupted, has high-speed access, low power consumption and resistance against collision. Such a ferroelectric memory is typically used as a main memory device or a recording medium in various electronic equipment having file storage and detection functions such as portable computers, cellular phones, gaming devices, etc.
In the ferroelectric memory device, a memory cell, which includes a ferroelectric capacitor and an access transistor, stores logic data '1' or '0' in accordance with an electric polarization state of the ferroelectric capacitor. For example, when a voltage is applied to both ends of the ferroelectric capacitor, a ferroelectric material is polarized according to a direction of an electric field. A switching threshold voltage to which a polarization state of the ferroelectric material is changed is called a coercive voltage. To read data stored in the memory cell, a voltage is applied to generate a potential difference between both electrodes of the ferroelectric capacitor, and a state of the data stored in the memory cell is sensed by a change of a charge amount excited to a bit line.
Referring to FIG. 1, when a ground voltage, for example, Vss or 0V, is applied to a ferroelectric material and an electric field is not applied to the ferroelectric material, the ferroelectric material is not polarized. When a voltage at both ends of a ferroelectric capacitor increases in a positive direction, a polarization level or charge amount thereof increases from zero to a state point A within a positive polarization region. At the state point A, a polarization is generated in one direction and a polarization level of the state point A reaches a maximum value. At this time, a polarization level, for example, a charge amount remaining in the ferroelectric material, is indicated by +Qs. If the voltage at both ends of the capacitor is reduced to the ground voltage Vss, the polarization level is not reduced to zero but instead remains at a state point B. A charge amount remaining in the ferroelectric material, for example, a residual polarization level, is indicated by +Qr.
Next, if the voltage at both ends of the capacitor increases in a negative direction, the polarization level is changed from the state point B to a state point C within a negative charge polarization region. At the state point C, the ferroelectric material is polarized in a direction opposite the polarization direction of the state point A. This polarization level is indicated by −Qs. If the voltage at both ends of the capacitor again falls to the ground voltage Vss, the polarization level does not fall to zero, but instead remains at a state point D. This residual polarization level is indicated by −Qr. When a magnitude of the voltage applied to both ends of the capacitor again increases in a positive direction, the polarization level of the ferroelectric material is changed from the state point D to the state point A.
FIG. 2 illustrates a memory cell of a memory cell array in a general ferroelectric memory device. As shown in FIG. 2, the memory cell is composed of an access transistor N1 and a ferroelectric capacitor C1. The access transistor N1 has a source terminal and a drain terminal, which are connected between an electrode of the ferroelectric capacitor C1 and a bit line BL, and a gate terminal connected to a word line WL. One electrode of the ferroelectric capacitor C1 is connected to the access transistor N1 and the other electrode is connected to a plate line PL.
As described above with reference to FIG. 1, when a voltage for generating an electric field is applied to a ferroelectric capacitor into which a ferroelectric material was inserted between its two electrodes, a polarization direction based on a spontaneous polarization is maintained even if the electrodes are in a floating state. A surface charge of the ferroelectric material based on the spontaneous polarization is not spontaneously lost due to leakage. If a voltage is not applied to the ferroelectric capacitor in an opposite direction to bring the polarization level to zero the polarization direction remains intact.
When a voltage applied to the ferroelectric capacitor in a positive direction is removed, a residual polarization of the ferroelectric material goes to a sate indicated by +Qr. In addition, when a voltage applied to the ferroelectric capacitor in a negative direction is removed, the residual polarization of the ferroelectric material goes to a state indicated by −Qr. Assuming that the residual polarization has the +Qr state at the state point B, and its logic state indicates data '0', then when the residual polarization has a −Qr state at the state point D, its logic state indicates data '1'. Thus, a difference in a charge amount when changing from the state point A to the state point B (as indicated by voltage dQ0) is discriminated from a difference in a charge amount when changing from the state point D to the state point A (as indicated by voltage dQ1), and data stored in the memory cell is read.
To read data stored in the memory cell a specific reference voltage generating apparatus for generating a reference voltage having a voltage value at a mid level between a bit line voltage value for reading data '1' and a bit line voltage value for reading data '0' is needed to sense and amplify a voltage change excited to a bit line.
FIG. 3 illustrates a timing diagram for reading data from a main memory cell in a ferroelectric memory device having a conventional reference voltage generating apparatus.
Referring to FIG. 3, when a read operation starts, sense amplifier and complementary sense amplifier path signals SA_PATH and RSA_PATH are enabled and bit line pairs are connected to corresponding sense amplifiers. Before the read operation, main bit line and sub bit line precharge signals BL_PR and RBL_PR are enabled, precharging bit lines, a main bit line BL connected to the memory cell, and a sub bit line BLB connected to a reference cell. Then, at the same time as the start of the read operation, the main bit line and sub bit line precharge signals BL_PR and RBL_PR are disabled. A selected word line SWL0 and reference word line RSWL1 are enabled, a plate line voltage is applied to a plate line PL, and a reference plate line voltage is applied to reference plate lines RPL. Subsequently, a voltage data "1" or data "0" corresponding to data of a selected main memory cell is provided to the main bit line BL, and a reference voltage is provided to the sub bit line BLB connected to the reference cell. Then, a sense amplifier senses a voltage difference of the bit lines BL and BLB in response to a sense amplifier enable signal SAEN. When data reading is completed by the sense amplifier, the main memory cell is restored to its first data state in conformity with the read data. After the sense amplifier enable signal SAEN is applied, the complementary sense amplifier path signal RSA_PATH is disabled cutting off the sense amplifier and the sub bit line BLB, enabling the sub bit line precharge signal RBL_PR and grounding the sub bit line BLB, thereby preventing a data reverse effect for a selected reference cell.
Current methods for generating a reference voltage in a ferroelectric memory device are directed to applying a paraelectric capacitor or a ferroelectric capacitor to a reference cell. The method of applying a paraelectric capacitor having a small dielectric constant in a highly integrated memory device affects chip size because the capacitor takes up a large area. The method of applying a ferroelectric capacitor is divided into two methods. The first method uses a capacitance of a non-switching area of a hysteresis curve shown in FIG. 1. For example, the dQ0 value, is used as a reference voltage for controlling the size of the ferroelectric capacitor. The second method uses all switching capacitances and non-switching capacitances of the hysteresis curve of FIG. 1. Such methods enable the development of reduced chip sizes, but do not always supply a stabilized reference voltage having a typical ferroelectric characteristic. Thus, reducing the reliability of a memory device including the ferroelectric capacitor.
FIGS. 4 and 5 illustrate characteristic changes when using a non-switching capacitance of a ferroelectric capacitor in a reference cell. FIG. 4 illustrates a relaxation effect and FIG. 5 illustrates an imprint effect.
With reference to FIG. 4, the relaxation effect occurs when an electric field is removed from a ferroelectric capacitor having data preserved therein for a long time, e.g., for several milliseconds or more. As shown in FIG. 4, a polarization value is reduced from a state point B to a state point E at the hysteresis curve of the ferroelectric capacitor. If the relaxation effect produces a level difference in a semiconductor device, a capacitance change arises in a non-switching area causing a reference voltage level change and failure of the device.
As shown in FIG. 5, the imprint effect occurs when a ferroelectric capacitor remains in a single polarization state for a long time and its hysteresis curve moves in a direction along a voltage axis. A ferroelectric capacitor having the imprint effect has a relaxation characteristic that is different than its relaxation characteristic from before the imprint effect occurred according to the direction of movement. In other words, a relaxation amount is reduced in conformity with the movement of the hysteresis curve toward the left, changing a reference voltage of the reference cell, thus reducing the reliability of device during a read operation.
A need therefore exists for a reference voltage generating apparatus and a driving method therefore for providing a stabilized reference voltage and that reduces a relaxation effect or an imprint effect in a ferroelectric capacitor in a reference cell.

Reference voltage generating apparatus for use in a ferroelectric random access memory (FRAM) and a driving method therefor


This invention describes a new geometry for a heat driven thermoacoustic me mover (i.e. acoustic motor) and its application to a thermoacoustic refrigerator and to an electricity generator. The heat driven acoustic refrigerator has no moving parts, and is thus extremely reliable, simple, and cheap to manufacture. Unlike previous heat driven acoustic cooling engines, it has good efficiency and compactness and is easy to start, avoiding destructively high temperatures upon start-up. The cooling engine is saleable over an extremely wide range of cooling capacities from integrated circuit and sensor cooling to building air-conditioning. The electricity generating engine has modest efficiency, but may be attractive in remote applications where high-reliability or low cost or low environmental noise or solar powering is important. The generator is likely to be most attractive in capacities of a few kW to below 100 W where a tiny engine would be impractical using other technologies.

1. Field of the Invention
This invention relates to a heat driven thermoacoustic motor, or sound generator, powering either a thermoacoustic refrigerator or an electricity generator. Specifically, the invention consists of a geometry and other optional components that improve the efficiency, power density, and ease of start-up for a thermoacoustic motor. Applications include remote or recreational (e.g. camping) or solar power requirements for cooling or electricity; or for residential or commercial cooling where the cost of fossil fuel is much lower than the cost of electricity or peak electrical loads need to be reduced. The heat driven cooling engine invention can be scaled down to very small sizes for the purpose of cooling integrated circuits or sensors.
2. Description of the Related Art
While some features and advantages of this invention depend of convenient optimization and adjustment of thermoacoustic parameters, some of the advantage derives from capitalizing on the potential for additional Stirling cycle heat transport in addition to the primary thermoacoustic heat transport.
Both the Stirling cycle and the thermoacoustic cycle share many features and a common parameter space. Both utilize a primary thermodynamic fluid medium (usually a gas) that executes a reciprocating motion and an oscillatory pressure. The primary thermodynamic medium is in thermal contact with a secondary "recuperative" thermodynamic medium (usually a solid). The secondary solid medium has pores or channels that allows fluid flow with little resistance. The primary medium converts the work done by the pressure change of the primary medium into some combination of a temperature change or a heat flow to or from the secondary medium. The function of the secondary medium is to alternately sink and store heat on one half of the cycle and then source and release heat on the other half of the cycle. The heat storage capacity of the secondary medium is very much larger than that of the primary medium.
The differences between the Stirling cycle and the thermoacoustic cycle are as follows. In an unlimited thermally diffusive medium, heat can diffuse about one "thermal penetration depth" in distance in the time of one oscillatory cycle. The secondary medium in a Stirling engine is called a "regenerator" and has pores or channels that are very small relative to a thermal penetration depth, thus largely suppressing any temperature oscillation of the fluid. The primary "rule" for the Stirling cycle is that heat transport in the regenerator is equal in magnitude, and opposite in direction to the mechanical power flow (or acoustic power flow) in the fluid.
Thus a regenerator in a perfect standing wave (pressure and velocity phasing is in quadrature) can sustain a large temperature difference from end to end but will transport no heat, since there is no acoustic power flow. This was the original intent of the regenerator in the Gifford & Longsworth "Pulse Tube Refrigerator", U.S. Pat. No. 3,237,421 (March 1966). in reality, the power flow in this regenerator was not zero and a substantial amount of beneficial heat transport was achieved by both the pulse tube and the regenerator. In the orifice pulse tube refrigerator (Radebaugh, "A comparison of three types of pulse tube refrigerators: New methods of reaching 60K", Advances in Cryogenic Engineering, 31, 779 (1986)) the amount of mechanical power flow in the regenerator is increased by the dissipative orifice which increases the regenerator's heat transport.
The secondary medium of a thermoacoustic engine is called a "stack" and its pore or channel size is comparable to a thermal penetration depth, which allows the fluid temperature to oscillate, while allowing imperfect thermal contact between the two media. The stack transports heat in a perfect standing wave, where phasing between pressure and velocity are in quadrature, because of the time delays or phasing of the thermal diffusive wave in the stack's pores or channels. Creating the standing wave environment for the stack is trivial compared to the traveling energy wave required for the regenerator, thus achieving the mechanical simplicity of the typical thermoacoustic engine. The direction of heat flow in a refrigerating stack is always towards the nearby pressure antinode (PAN) of the standing wave (where the acoustic pressure distribution is at a maximum and the acoustic velocity is at a minimum or zero), and directed away from the PAN for a prime mover (motor).
However, the standing wave in a thermoacoustic engine is never perfect, and there is always acoustic energy flow through the stack. Because of this energy flow, there is always a Stirling component to the heat transport, in addition to the thermoacoustic transport. While the magnitude of the Stirling component may be small compared to the thermoacoustic component (perhaps 10%), it is either contributing to the performance of the engine (additive) or detracting (subtractive). So if the Stirling component of heat transport is managed properly in a thermoacoustic engine design, it will generally result in at least a 20% improvement in the efficiency, relative to an engine having a subtractive Stirling component.
In the original Wheatley thermoacoustic refrigerator, (Wheately, et al., "Acoustical heat pumping engine", U.S. Pat. No. 4,398,398 (Aug. 16, 1983)), the acoustic power source (the electromagnetic driver) is situated some distance from the cold end of the refrigerating stack. Thus acoustic power flows from the cold end of the stack to the warm end of the stack. The resulting Stirling component of heat transport is oriented from warm to cold and thus degrades the efficiency of the refrigerator.
In the second generation thermoacoustic refrigerator by Hofler, (Hofler et al., "Acoustic Cooling Engine", U.S. Pat. No. 4,722,201 (Feb. 2, 1988)), the acoustic power source (i.e. the driver) is situated at a PAN near the hot end of the refrigerator stack. The acoustic resonator is effectively 1/4 of a wavelength, with large spherical volume at the end opposite the driver. The spherical volume approximates an open-end acoustic condition for the resonator. One reason for this invention was to prevent conduction or acoustic convection of heat from the warm driver to the cold end of the stack. However, this also orients the direction of the Stirling component of heat transport from the cold end of the stack to the warm end, thus improving the efficiency of the refrigerator.
In the heat driven thermoacoustic cooling engine by Wheatley et. al., "Heat-driven Acoustic Cooling Engine Having No Moving Parts", U.S. Pat. No. 4,858,441 (Aug. 22, 1989), the usual thermoacoustic prime mover is combined with the second generation thermoacoustic refrigerator, all combined in a 1/4 wavelength portion of the standing wave (from PAN, to velocity antinode or VAN). This engine is shown schematically in FIG. A. While this engine is simple and has no moving parts, it has very poor efficiency, with a total COP in the range of 0.05 to 0.1 for a modest cooling temperature span. COP is an acronym for "coefficient-of-performance." Total COP is the cooling power divided by the heat input power, which can be much greater than unity for the combination of two Carnot cycle engines; a motor and refrigerator combination having perfect thermodynamic efficiency. There are two primary reasons why the efficiency is so low.
In FIG. A, the cooler stack pumps heat Q upward, while the acoustic power W comes from the prime mover stack above it, creating a downward acoustic power flow. Thus the Stirling component of heat transport is directed upward enhancing the efficiency of the cooler stack. However, heat flows downward through the prime mover stack from hot to ambient temperature and the Stirling component of acoustic power flow is thus directed upward in opposition to the thermoacoustic component of mechanical power provided to the cooler stack. This substantially degrades the efficiency of the prime mover stack.
The second disadvantage of the old design is that the prime mover and cooler stacks must fit into mutually exclusive regions of the standing wave. Typically, for small temperature span thermoacoustic engines, the stack performs best when it occupies a region in the standing wave extending from 0.08 to 0.2 radians, measured from the pressure antinode (PAN). This is more or less true for both prime mover stacks and for cooler stacks. Hence, in the original design of Wheatley U.S. Pat. No. '441, the prime mover stack is too close to the PAN and the cooler stack is too far from the PAN for optimal performance.
While the two stacks in FIG. A could have different diameters, this would be difficult to accomplish without increasing the undesirable distance between the stacks. Also, it would not have the desired effect of altering the power balance between the two stacks. Increasing the diameter of one stack would increase the cross-sectional area of the stack but would decrease the acoustic velocity. The two effects would roughly cancel, leaving the power capacity of the stack unchanged.
Another heat driven cooler invention is the thermoacoustically driven orifice pulse tube refrigerator, patented by Swift et al, "Acoustic Cryocooler", U.S. Pat. No. 4,953,366 (Sep. 4, 1990). This is an effective and moderately efficient cryocooler engine having no moving parts. However, the orifice pulse tube refrigerator is only efficient in the cryogenic temperature regime and is inherently inefficient for small temperature spans. The orifice pulse tube refrigerator is essentially a Stirling engine variant where the cold temperature cooling power is comparable in magnitude to the mechanical power dissipated as heat in the orifice. For cryogenic coolers where even the Carnot COP is very small, the energy wasted by the orifice is almost negligible and less important than other factors. For a small temperature span refrigerator, such as an air conditioner, the orifice pulse tube refrigerator, by itself, would have a COP less than unity. And a heat driven version would have a total COP very much less than unity. This is a prohibitively poor efficiency.
The heat driven cooler topology disclosed in this invention allows independent positioning of the two engine stacks with respect to the standing wave, and also aligns the acoustic power flow and the heat flow to be anti-parallel in both stacks for best efficiency. The topology also allows the power capacity (heat power or acoustic power as the case may be) of each stack to be independently adjusted by changing the diameter of each stack. This is advantageous for efficiency optimization in general, and for ensuring easy engine start-up with a modest hot temperature.

High-efficiency heat-driven acoustic cooling engine with no moving parts

The United States of America as represented by the Secretary of the Navy


Exemplary methods for reducing sync time in a precision time protocol (PTP) network include receiving, by a first PTP slave port of a first network device, timing messages from a second PTP master port of a second network device. The methods include maintaining a PTP master clock based on timing information included in the timing messages received from the second network device via the first PTP port. The methods further include receiving, by a third PTP passive port of the first network device, timing messages from a fourth PTP master port of a third network device. The methods include determining the third PTP passive port is a protective passive port based on a stepsRemoved value of the third network device, and maintaining an auxiliary clock based on the timing information included in the timing messages received from the third network device via the third PTP port.

The Precision Time Protocol (PTP) is a protocol utilized for synchronizing clocks throughout a network. PTP was originally defined by the Institute of Electrical and Electronics Engineers (IEEE) 1588-2002 standard, entitled "Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems" (hereby incorporated by reference), and released in 2002. In 2008, a revised standard, IEEE 1588-2008 entitled "IEEE Standard for a Precision Clock Synchronization Protocol for Networked Measurement and Control Systems" (hereby incorporated by reference) was released. This new version, also commonly known as PTP Version 2 (PTPv2), improves accuracy, precision, and robustness. IEEE 1588-2008 was initially utilized primarily by instrumentation and control applications. The telecom industry, however, has since adopted IEEE 1588-2008 as a solution for providing time synchronization for packet network applications such as mobile backhaul. These packet network applications, however, require microsecond or better time distribution over the network and high quality fault tolerance.
IEEE 1588-2008 defines a best master clock algorithm (BMCA), executed at each PTP clock in the PTP domain, for configuring the PTP clocks to be a grandmaster, boundary clock, or slave clock. By utilizing their BMCA to determine their roles in the PTP domain, the PTP clocks converge to form a synchronization tree. While the synchronization tree is being formed, all clocks start locking (i.e., synchronizing) to their masters. Typically, it requires several minutes for each PTP clock to synchronize to its master. After the synchronization tree is formed, if one or more of the PTP clocks or the network experience a fault, all the downstream clocks will rearrange/re-converge to form a new synchronization tree. During this re-convergence period, timing transients will occur as new master and slave ports are selected by the BMCAs. These timing transients result in a period of time where the clock quality advertised to the ultimate slave clocks is inaccurate. These timing transients persist until all PTP clocks in the synchronization tree actually acquire synchronization to their new masters. In other words, for several minutes, or perhaps an hour or longer in larger networks, the timing accuracy is not as good as advertised. This results in the application being provided with inadequate timing accuracy. The timing transients that occur during the re-convergence period are not acceptable by packet network applications in the telecom domain.
Known techniques, such as holdover, exist to work around certain failure/recovery scenarios. Such techniques, however, are inadequate for prolonged outages. Further, because the BMCA will advertise a clock quality that is not true during failure-induced rearrangements, holdover techniques will not work.

Method for robust PTP synchronization with default 1588V2 profile


An embodiment of a flash memory device with NAND architecture, including a matrix of data storage memory cells each one having a programmable threshold voltage, wherein the matrix is arranged in a plurality of rows and columns with the memory cells of each row being connected to a corresponding word line and the memory cells of each column being arranged in a plurality of strings of memory cells, the memory cells in each string being connected in series, the strings of each column being coupled to a reference voltage distribution line distributing a reference voltage by means of a first selector, wherein each string further includes at least one first shielding element interposed between the memory cells of the string and said first selector, the first shielding element being adapted to shield the memory cells from electric fields that, in operation, arise between the string of memory cells and the first selector.

Memory devices are commonly used to store data either temporarily or permanently in a number of applications; for example, in a non-volatile memory device, the data is preserved even when a memory device power supply is off.
Flash memory devices are non-volatile memories wherein each single memory cell may be programmed electrically, but a large number of memory cells, forming a memory block, are erased at the same time. Typically, each memory cell consists of a floating-gate MOS transistor, which stores a logic value defined by its threshold voltage (which depends on the electric charge stored on the floating gate).
In particular, during the programming of the floating-gate MOS transistor, electrons are injected, for example, by means of the known Fowler-Nordheim mechanism, into the floating gate; the retention of such electrons by the floating gate causes the memory device non-volatility. Vice versa, during the erasing, the floating gate is substantially emptied of the electrons, which were injected during the programming.
In a flash memory device with NAND architecture, the memory cells are grouped in strings (or stacks), each one consisting of a set of memory cells that are connected in series between a drain select transistor, connected to a bit line of the memory cells block, and a source select transistor, connected to a reference voltage distribution line distributing a reference voltage (such as a ground voltage); groups of said strings of memory cells are connected to a same bit line, and thus they are connected in parallel to each other. When all the memory cells belonging to a same string are to be programmed, usually the first memory cell that undergoes the programming operation is the memory cell connected to the source select transistor of the string, followed by the subsequent memory cells of the string proceeding towards the memory cell connected to the drain select transistor.
As known, for programming a memory cell belonging to the selected string, a significantly high programming voltage (such as 18V) is applied to its control gate, while control gates of the remaining memory cells of the string are driven by a programming pass voltage, typically lower (such as, 9 or 10V) than the programming voltage, but sufficient to turn them on. The bit line corresponding to the selected string is biased at a voltage that depends on the data to be programmed into the considered memory cell: if the data to be programmed is a "0" (by convention, corresponding to a memory cell with a positive threshold voltage), the bit line is biased at the reference voltage (such as 0V); if instead the memory cell is intended to store a "1" (which, by convention, corresponds to an erased memory cell, with a negative threshold voltage; thus, when the data to be stored is a "1", the corresponding memory cell is left in the original state), the bit line is biased at a higher voltage, such as the memory device supply voltage (e.g., 3V). The other bit lines of the memory matrix are brought to the supply voltage. The control terminal of the drain select transistor corresponding to the selected string is driven by the supply voltage, thus in case the data to be programmed is a "0" the drain select transistor is turned on, whereas in case the memory cell is intended to store a "1" the drain select transistor is kept off. The source select transistor receives at its control terminal the reference voltage, thus resulting in the select transistor being turned off.
In detail, when a logic value equal to "0" is to be stored into the selected memory cell, the threshold voltage thereof is shifted towards higher values compared to the erased state (that corresponds to a logic "1"). For this purpose, electrons are to be injected into the floating gate; a relatively high voltage difference ("programming voltage") between the control gate and the drain terminal of the selected memory cell is applied. In particular, the drain terminal of the selected memory cell is kept at the reference voltage, since the remaining non-selected memory cells of the string are turned on so as to transfer the reference voltage (i.e., 0V) from the bit line to the drain of the memory cell; the control gate voltage applied to the unselected memory cells of the string is not excessively high, so as to inhibit charge injection into the floating gates thereof.
When the data to be stored into the selected memory cell is a logic value equal to "1", its threshold voltage remains unchanged (under the assumption that the memory cell starts from an erased state). For this purpose, the voltage difference between the control gate and the drain terminal of the selected memory cell is kept lower than the programming voltage, so as to be insufficient for causing a charge injection into the floating gate thereof. All the memory cells in the string are on, and, the drain select transistor being off, the voltage of the drain terminal of the selected memory cell is boosted toward relatively high values (such as, 7V) thanks to the capacitive coupling effect between the selected memory cell and the remaining memory cells of the string.
A function of the memory devices is to ensure that the memory cells are correctly programmed. Indeed, when one (or more) memory cells of the memory device are programmed, corruption of the data stored into the remaining memory cells may occur due to effects like an unexpected and undesired charge injection into the floating gates thereof. Such an event may cause the threshold voltages of the memory cells to take values that are different (higher or lower) than the expected values.
These spurious changes of the memory cells' threshold voltages may cause errors when the data is read. Such effect, which is also experienced in NAND memories with two-level memory cells, is more and more of a problem in multi-level NAND memories, wherein each cell stores multiple bits, corresponding to multiple different threshold voltage levels; in this case in fact the margins which are available for discriminating the different stored logic values are reduced.
For better clarity, let the case be considered of a programming operation performed on a memory cell belonging to a selected string of a NAND flash memory device. Let it be assumed that the memory cell to be programmed is the second (starting from the source select transistor) memory cell in the string, whereas the first memory cell has already been programmed. As mentioned above, during the program operation, the control gate of the first memory cell—the one which is directly connected to the source select transistor—is driven by the programming pass voltage, whereas the control gate of the second memory cell is driven by the programming voltage.
The voltage of the drain terminals of the memory cells belonging to the unselected string is boosted toward relatively high values (such as, 7V). In particular, the drain terminal of the first memory cell belonging to the unselected string is boosted to said relatively high values (such as, 7V) thanks to the capacitive coupling effect with the remaining memory cells of the string. The voltage difference between the programming pass voltage and the voltage (i.e., the reference voltage) applied to the control electrode of the source select transistor may cause an undesired charge injection (so-called "Source/drain Hot-Carrier Injection Disturbance", or SDHCID for short) into the floating gate of the first memory cell of the unselected string, which may vary its threshold voltage. In particular, electron-hole pairs may be generated at the source select transistor and the generated electrons are accelerated towards the floating gate of the (first) memory cell belonging to the unselected string so causing an undesired programming thereof. This phenomenon is more apt to occur the higher the difference between the programming pass voltage and the voltage (i.e., the reference voltage) applied to the control electrode of the source select transistor; in particular, such phenomenon is more apt to occur the higher the transversal electric field between the source select transistor and the unselected memory cells.
Similar problems are encountered when the string includes memory cells which are intended to store a logic value equal to "1" and in particular when the first memory cell of the string is to be left in the erased state. Indeed, also in this case the transversal electric field between the source select transistor and the first memory cell (with the voltage of the drain terminal boosted to a high value) may cause an undesired programming thereof.
In other words, the "SDHCID" affects the threshold voltage of the first memory cells belonging to memory cell strings, which are not selected for the programming operation (meaning both unselected strings and selected strings but containing memory cells that are to left in the "1" state). Indeed, the voltage difference between the programming pass voltage applied to the control gate of the first memory cell of the string and the voltage (i.e., the reference voltage) applied to the control electrode of the source select transistor may cause an undesired charge injection into the floating gate of the first memory cell of each string of the block.
It should be noted that in bi-level memory devices such problem is particularly detrimental when the first memory cell of the string is intended to store a data corresponding to the "1", since even a small charge injection may cause a shift of the threshold voltage towards the programmed state such that the first memory cell, during the reading operation, is non-conductive (i.e., programmed to "0" logic value) instead of conductive (i.e., erased to "1" logic value).
In multi-level memory devices the "SDHCID" is particularly felt also when the data to be stored into the first memory cell belonging to the string, which is not selected for the programming, corresponds to a programmed state. In fact, the undesired charge injection may cause a shift of the threshold voltage of the first memory cell toward threshold voltage levels corresponding to a (programmed) state different from the desired one.
Similar considerations also apply when the program operation is performed on the other memory cells of the selected string.

NAND flash memory with reduced programming disturbance


A fan clutch (A') includes an eddy current drive (224) having a first, magnetic field producing drive component rotatable with the output and a second, coupling drive component rotatable with the input in the form of a sheave (50'). The first drive component includes permanent magnets (226). The second drive component is of a one-piece construction including a steel ring (238) embedded in a body portion (241) formed of aluminum. The steel ring (238) includes locating ears (310) for properly locating and retaining the ring (238) in a mold half (324). Positioning tabs (312, 314) extend from the faces (302, 304) of the ring (238) and prevent the ring (238) from floating in the volume between the mold halves (318, 324) which forms the body portion (241) during the introduction of the molten aluminum. The body portion (241) is integrally formed with circumferentially spaced air moving vanes (264) and an annular disc portion (260) for mounting to the sheave (50').

The present invention generally relates to eddy current drives, relates particularly to improved drive components for eddy current drives, and relates specifically to improved integral drive components for eddy current drives.
In a typical eddy current drive, a first, magnetic field producing drive component such as in the form of permanent magnets is mounted for rotation with one of the input or output of a rotational control apparatus such as a clutch for magnetically coupling with a second, coupling drive component mounted for rotation with the other of the input or output. The second, coupling drive component was typically in the form of a first ring formed of electrically conductive material such as copper sandwiching a second ring of magnetic flux conductive material such as steel against a mounting body portion formed of heat conductive material such as aluminum so that the body portion acts as a heat sink. Screws extended through the first and second rings and were threaded into the body portion.
Prior coupling drive components suffered from various problems and deficiencies. Specifically, heat is generated in the copper ring but its transfer to the body portion is restricted by the steel ring positioned between the copper ring and the body portion. Additionally, when exposed to heat, copper will oxidize reducing the efficiency of the eddy current drive. Further, the mechanical attachment of the steel and copper rings to the body portion increases the number of components and assembly required and is subject to loosening and/or separating and thereby detrimentally affecting reliability.
Thus, a need exists for improved coupling drive components for eddy current drives which overcome the problems and deficiencies of prior eddy current drives.

Integral steel-aluminum ring for eddy current activated friction clutch


Radiation-hard, steady-state imaging bolometer. A bolometer employing infrared (IR) imaging of a segmented-matrix absorber of plasma radiation in a cooled-pinhole camera geometry is described. The bolometer design parameters are determined by modeling the temperature of the foils from which the absorbing matrix is fabricated by using a two-dimensional time-dependent solution of the heat conduction equation. The resulting design will give a steady-state bolometry capability, with approximately 100 Hz time resolution, while simultaneously providing hundreds of channels of spatial information. No wiring harnesses will be required, as the temperature-rise data will be measured via an IR camera. The resulting spatial data may be used to tomographically investigate the profile of plasmas.

Bolometers are a standard magnetic fusion plasma diagnostic. However, it is problematic to have a sufficient number of channels and views to accurately reconstruct the plasma radiation profile. In addition, every discrete detector channel generally has 2-4 wire leads for carrying low-level signals away from the plasma and through a vacuum interface, typically resulting in complicated wiring harnesses inside high-temperature, high-nuclear-radiation environment devices, and leading to high cost and complexity.
Current bolometry for fusion plasmas employs discrete thin-foils which are heated by plasma radiation, and the resulting temperature rise is detected by a metal resistor or thermistor bonded to the back side of the foil, often separated by an insulating film. Occasionally, a single-channel infrared (IR) detector has been used to monitor the rise in temperature of the foil, so as to provide better electrical noise immunity. In the case of short-pulse plasma radiation, or when studying the energy deposited by ion, neutral, or electron beam, IR imaging of the back side of a foil or plate target has been employed for determining the instantaneous distribution of energy in the beam. The difficulty with using this technique to observe a long-pulse plasma, is that the lateral heat flow in the foil or plate interferes with subsequent images and confuses the measurement. In addition, a foil which is sufficiently thin to have reasonable time response must be cooled for longer time intervals in order to prevent melting or radiation damage, or nonlinear effects from adversely affecting the measurement. Finally, the detectors must be radiation hardened in order to survive the neutron and gamma fluences from a long-pulse DD or DT machine. So-called "silicon bolometers" and pyroelectric detectors have the advantage of responding directly to the incident power; however, such detectors will not work in these harsh environments.
Plasmas often have complex geometry, and multichannel imaging (as well as tomography) is desired for modeling analysis. A radiation-hard imaging bolometer, using a segmented-absorber matrix, combined with a pinhole-camera geometry and sensitive IR camera has recently been proposed. Such an apparatus would generate several thousand channels of data, while eliminating wires crossing vacuum interfaces.
In "A Rad-Hard, Steady-State, Digital Imaging Bolometer System For ITER," by G. A. Wurden, in Diagnostics for Experimental Thermonuclear Fusion Reactors, edited by P. E. Stott et al. (Plenum Press, New York, March, 1996), pp. 603-606, a pinhole imaging design, with the plasma radiation striking a compact, segmented, rear-surface-cooled "foil," where each segment of the "foil" corresponds to one imaging resolution element or "pixel," is described. Each pixel absorber is raised from the back cooling block (which may be held at a constant reference temperature), and the height of the pixels (and the material thermal conductivity) is adjusted for rapid axial heat flow compared to the relatively longer lateral heat flow path between pixels. The passive absorber matrix is imaged in the infrared, using two metal mirrors, which allows a neutron-sensitive, state-of-the-art, 12-bit digital video IR camera to be positioned out of the line-of-sight of the neutron flux from the plasma. Some of the pixels may be positioned outside of the plasma field-of-view, to act as "background" pixels, if required. The front surface of the absorbing matrix may initially be a "blackened coating" (in accordance with common bolometer design). However, during use, plasma contamination of the surface occurs. No wires exit the vacuum interface. A schematic representation of the bolometer apparatus is shown in FIG. 2 of Wurden. Design parameters are given for an aluminum absorbing matrix having aluminum pixels, although different absorbing materials may be bonded to the end of each pixel according to the teachings of Wurden.
Wurden identifies a potential difficulty in the use of the apparatus as being due to infrared radiation from hot objects (500.degree.-1000.degree. C. hotter than the segmented matrix in the bolometer itself) directly in the field of view. These objects will radiate approximately 1000 times more strongly than the thermal emission from the matrix in the 3-5 .mu.m region, due to blackbody emission. This stray light interferes with the light viewed from the front surface of the segmented matrix. Two suggestions are made for overcoming this difficulty. First, the matrix itself could be operated at elevated temperatures. Additionally, the matrix could be viewed from its back surface, while cooling is applied to the sides of each pixel. No teachings are provided as to how either of these suggestions might be accomplished.
Accordingly, it is an object of the present invention to provide a bolometer for infrared spatial imaging of plasmas which is unaffected by stray light emission from hot surfaces surrounding the plasma.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

The Regents of the University of California


Resistive heaters formed in two mask counts on a surface of a grating of a thermo optic device thereby eliminating one mask count from prior art manufacturing methods. The resistive heater is comprised of a heater region and a conductive path region formed together in a first mask count from a relatively high resistance material. A conductor formed from a relatively low resistance material is formed directly on the conductive path region in a second mask count. Thermo optic devices formed by these two mask count methods are also described.

The art of making and developing new uses for thermo optic devices continues to emerge. Presently, thermo optic devices are used as filters, switches, multiplexers, waveguides, and a host of other semiconductor and optical transmission devices.
With reference to FIGS. 1A and 1B, a thermo optic device in accordance with the prior art is shown generally as 110. It comprises a cladding 115 that includes an upper cladding 114 and a lower cladding 112. A core 116 is defined by the cladding and is generally formed of a material having a higher or lower refractive index than that of the cladding. The core 116 may, for example, define an optical waveguide, such as a Y-shaped optical splitter having an input waveguide 122 and two output waveguides 124, 126. The core 116 together with the cladding 115 are sometimes referred to as a grating and are disposed on a substrate 118. The substrate may be formed of silicon but is not required to be. A heater 120 is disposed adjacent to the cladding 115.
During use, a control element (not shown) delivers current to the heater 120, to change an optical characteristic of the thermo optic device. For example, in a Bragg grating formed with a polymer grating, when current is delivered to heater 120, the refractive index of the polymer will change as a result of the thermo optic effect. In turn, this refractive index change affects the wavelength of light that satisfies the known Bragg reflective condition so that a different wavelength is now Bragg reflected in the optical waveguide.
If the process is repeated at another temperature, which is a function of current delivery and heater characteristics, another wavelength will satisfy the Bragg reflective condition. In this manner, the thermo optic device 110 is made tunable. Such a device will normally be operated in a steady state condition so that a single wavelength will satisfy the Bragg reflection condition over a given time interval.
With reference to FIGS. 1C and 1D, a portion of the thermo optic device 110 is shown in greater detail. In particular, the heater 120 is formed with contacts 121, 123 and conductors 131, 133 to, ultimately, connect to the control element during use.
Unfortunately, the heater 120, together with its associated contacts 121, 123 and conductors 131, 133, requires three fabrication masking steps to form with conventional processes, i.e., one masking step to form the heater, one to form the contacts, and one to form the conductors. This unnecessarily complicates manufacturing and wastes resources and finances.
Accordingly, the thermo optic arts desire improved heaters that are cheaper and quicker to produce, e.g., formed by fewer mask counts, without any corresponding sacrifice in quality, reliability or longevity.

Resistive heater for thermo optic device


A hyperspectral scene generator generates a projected linear scene where the spectral characteristics at each location that forms the scene are dynamically and arbitrarily controllable. The generator can be controlled to generate a projected linear scene including a targeted object and arbitrary spectral content that duplicates the spectral content of real targets and backgrounds to facilitate testing of target identification software of a hyperspectral imaging system in view of expected actual field operation of the sensor of the imaging system.

A hyperspectral imaging system operates to identify a targeted object solely based upon detection of energy reflected from or thermally generated by the object. The hyperspectral imaging system typically includes a linear field of view hyperspectral sensor containing a single pixel, or one or more rows of pixels, which can detect optical energy having wavelength bandwidths spanning, for example, the UV/visible through the MWIR and LWIR ranges. In addition, the hyperspectral imaging system usually includes target identification software that operates to automatically acquire, identify, classify and track a targeted object based on the spectral energy detected at the pixel or pixels of the sensor. For example, in a military application, a hyperspectral imaging system can differentiate between detected spectral characteristics representative of camouflage paint and foliage to determine that a military target is present in an imaged region. In addition, a hyperspectral imaging system can evaluate detected infrared spectral signatures to determine that certain biochemical agents are present within an imaged region.
Testing of early prior art hyperspectral imaging systems, which typically did not have any accompanying target identification software, primarily involved calibrating the sensor. In a calibration test, the radiometric performance of the sensor, which includes physical performance parameters such as sensitivity, resolution and spectral sensitivity, is evaluated. Based on the results of radiometric performance testing, the operation of sensors of different hyperspectral imaging systems could be compared.
With the improvement of imaging technologies, target identification software began to be included in a hyperspectral imaging system. Advanced hyperspectral imaging systems now include highly complex target identification software which has the capability to process the very large amounts of spectral data likely to be collected in current hyperspectral imaging system applications. For example, in a typical military application, the hyperspectral imaging system must be able to process the large amounts of spectral data that would be collected based on the presence of a countermeasure that is placed in an imaged region to conceal a targeted object and which causes the sensor to detect a plurality of spectral characteristics that normally would not be present in the imaged region. In addition, a substantial amount of spectral data must be processed to identify the presence of an object in an imaged region where the energy radiated from the object occupies less than the size of a pixel of a sensor of a hyperspectral imaging system. As the target software became an integral part of the hyperspectral imaging system, testing of a hyperspectral imaging system now required, in addition to calibrating the sensor, evaluating how well the target software identified or otherwise extracted target and position information from the spectral data collected by the sensor.
In the prior art, the complex target software is usually tested independently of the operation of the hyperspectral sensor itself. In common prior art testing of the target software, test software creates a digital representation of the spectral emissions or reflections expected to occur in a region containing a target and the digital representation is used to validate the target software. This isolated testing of the target software is not always adequate and accurate because it assumes (i) that the effects upon the sensor of any non-linear mixing of spectrum, which occurs when one object reflects optical energy onto another object, can be ignored; and (ii) that the sensor does not include an anomaly that would cause the targeting software to be less effective. Thus, the independent testing of the target software does not detect and compensate for any hyperspectral sensor anomaly, which can lead to potentially invalid test results concerning the overall operation of the hyperspectral imaging system.
In addition, laboratory or bench test scene generation systems that were developed in the prior art can project a predetermined scene including a target to a hyperspectral imaging system to provide that the sensor and the target software functionalities can be evaluated. Such prior art bench testing systems, however, only provide that a limited number of different scenes including a target can be projected and do not permit dynamic and arbitrary control of the spectral and spatial characteristics of a projected scene. See D. B. Beasley, D. A. Saylor, J. Buford, "Overview of Dynamic Scene Projectors at the U.S. Army Aviation and Missile Command," Proc. SPIE Vol. 4717, pp. 136–147, April 2002, incorporated by reference herein. As a result, current bench testing techniques do not provide that the spectral and spatial characteristics of a projected scene can be sufficiently controlled, such that testing of a hyperspectral imaging system can be performed using a projected scene that simulates all of the spectral and spatial parameters that may exist in a natural scene.
In view of the limitations of the bench testing systems, actual field testing, such as placing a hyperspectral imaging system in an airplane and flying the system over a natural scene including a test target, has become a standard method for testing and demonstrating the performance of a hyperspectral imaging system. Such field testing, however, is costly and often is unrepeatable and uncontrollable. Moreover, in many circumstances, even a flight field test may not provide the variety or the correct background spectral signatures required to test an application of the hyperspectral imaging system.
Thus, the various prior art hyperspectral imaging system testing techniques cannot test the system repeatedly under controlled conditions that simulate the spectral and spatial characteristics expected to exist in a natural scene including a target, and that can also determine whether a spectral variation that sometimes may be present in a natural scene will cause the target software to fail to identify the target in such modified natural scene.
Therefore, a need exists for system and method for generating a projected linear scene having spectral and spatial characteristics that can be arbitrarily and dynamically controlled where the system and method can be implemented in a laboratory setting to perform repeatable testing of a hyperspectral imaging system for both radiometric and target identification software performance.

Hyperspectral scene generator and method of use