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Many potential lignocellulosic feedstocks are available today, including agricultural residues, woody biomass, municipal waste, oilseeds/cakes and seaweed, to name a few. At present, these materials are often under-utilized, being used, for example, as animal feed, biocompost materials, burned in a co-generation facility or even landfilled.
Lignocellulosic biomass includes crystalline cellulose fibrils embedded in a hemicellulose matrix, surrounded by lignin. This produces a compact matrix that is difficult to access by enzymes and other chemical, biochemical and/or biological processes. Cellulosic biomass materials (e.g., biomass material from which the lignin has been removed) is more accessible to enzymes and other conversion processes, but even so, naturally-occurring cellulosic materials often have low yields (relative to theoretical yields) when contacted with hydrolyzing enzymes. Lignocellulosic biomass is even more recalcitrant to enzyme attack. Furthermore, each type of lignocellulosic biomass has its own specific composition of cellulose, hemicellulose and lignin. | {
"pile_set_name": "USPTO Backgrounds"
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Source tracking refers to a procedure where an angle is determined between a single antenna and a phased array of multiple antennas. The goal of a source-tracking estimation algorithm is to locate a source with respect to a phased array. Source tracking can be done using a phased array at a receiver and a single antenna at a transmitter. This configuration is known as Angle-of-Arrival (AoA). Source tracking can also be done using a phased array at a transmitter and a single antenna at a receiver. This configuration is known as Angle-of-Departure (AoD). The source-tracking estimation algorithms are also referred to as Time-Delay-of-Arrival (TDoA) or Direction-of-Arrival (DoA). | {
"pile_set_name": "USPTO Backgrounds"
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Providing telephone communication services to multiple passengers of airplanes has become common. Prior art systems use on-board equipment (i.e.,equipment co-located with the airplane) which provides multiple communication channels between the airplane and a ground-based antenna which is in range of the airplane. The ground-based antenna is connected to a Public Switched Telephone Network (PSTN) which provides communication services to ground-based telephony equipment. Ground-based antennas can be linked together over terrestrial hard-wired links or though satellite links (e.g., geosynchronous satellite links).
One prior art, airplane communication system pre-assigns a "user code" or "personal identification number" (PIN) to passengers who might want to use on-board communication resources during their flight. The user code or PIN is assigned to a passenger before the passenger embarks. The passenger can disseminate the user code to any person who might want to reach the passenger during the flight. To register with the system or to place a call during the flight, the passenger enters the pre-assigned user code into the seat back handset.
The system checks a registration database to determine the airplane's location and the seat at which the passenger is located. After the system identifies the airplane's location and sends a message to the airplane via an in-range ground-based antenna, the passenger's seat back handset notifies the passenger of the incoming call.
For a ground-to-air call, a person wishing to contact the passenger during the flight (referred to herein as a "ground calling party") can do so by dialing a central system number (e.g., a "1-800" number), entering the passenger's pre-assigned user code, and entering the ground calling party's phone number. The system then contacts the passenger and, if the passenger accepts the call, the system calls the ground calling party back. The process of first calling a central number and being contacted by the system in a second, return call is referred to as "two-stage dialing with callback".
Several aspects of this prior art system are inefficient and make using the system inconvenient for both the passenger and others who wish to contact the passenger. For example, each airplane communication system has a number of available communication numbers which it can allocate to passengers. The airplane communication system must register and occasionally re-register every available number, whether or not the numbers are actually used by passengers. Registration and re-registration traffic consumes large amounts of system resources.
In addition, as explained previously, the prior art system uses two-stage dialing with callback, which is less convenient than if the ground calling party could directly contact the passenger using a single phone number. In addition, the prior art system does not accommodate passengers who do not have a pre-assigned user code or PIN. The requirement of the pre-assigned user code is also undesirable because the ground calling party must have knowledge of the user code in order to contact the passenger.
A group of co-located passengers traveling in a common vehicle (e.g., an airplane, bus, ship) are referred to herein as a "mobile user group" or "co-located mobile users". Where there are mobile user groups, it is desirable to be able to serve tow groups of passengers, i.e., those that have PIN cards and those that do not. In addition, where the communications link between passengers in a vehicle and non-passengers is a satellite link, only a limited number of communication channels may be available for use.
What is needed is a method and apparatus which reduces the quantity of registration traffic, allows direct inward dialing to a passenger during ground-to-air call attempts, direct outward dialing by passengers, and minimized loading on the system. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates to a new and distinct cultivar of Hibiscus plant, botanically known as Hibiscus rosa-sinensis, and hereinafter referred to by the name ‘Boreas Yellow’.
The new Hibiscus plant is a product of a planned breeding program conducted by the Inventor in Sabro, Denmark. The objective of the breeding program is to create new strong Hibiscus plants with attractive and long-lasting flowers.
The new Hibiscus plant is a naturally-occurring branch mutation of Hibiscus rosa-sinensis ‘Boreas’, disclosed in U.S. Plant Pat. No. 21,618. The new Hibiscus plant was discovered and selected by the Inventor on a single flowering plant within a population of plants of ‘Boreas’ in a controlled greenhouse environment in Sabro, Denmark in April, 2009.
Asexual reproduction of the new Hibiscus plant by vegetative terminal cuttings in a controlled greenhouse environment in Sabro, Denmark since August, 2009 has shown that the unique features of this new Hibiscus plant are stable and reproduced true to type in successive generations. | {
"pile_set_name": "USPTO Backgrounds"
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For a typical child, the process of learning to read and write usually begins during the pre-school years or kindergarten. Using conventional teaching methods, a child initially learns to identify the letters of the alphabet. Then, beginning with short two and three letter words, the child is taught to string together the sounds of the letters to identify words. Once the child has become proficient at reading short words, the process can be expanded to teach the child to sound out and spell longer words, eventually leading to reading and writing. Unfortunately, teaching a child to read and write using conventional methods can be a lengthy process. It is not until about the third grade that a typical child becomes relatively proficient at reading.
Graphic objects that are recognizable to children are sometimes used to facilitate the learning process. For example, a pictograph of an apple can be associated with the letter “a,” a pictograph of an egg can be associated with the letter “e,” and a pictograph of an umbrella can be associated with the letter “u.” To generate learning materials that include such pictographs can be very costly, however, due to the complexity in correctly associating the pictographs with the letters. Indeed, such processes are typically performed quasi-manually using a graphics application and can be very labor intensive. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention is directed to materials and methods involving extracellular matrix signalling moleculesxe2x80x94polypeptides involved in cellular responses to growth factors. More particularly, the invention is directed to Cyr61-, Fisp12-, and CTGF-related polynucleotides, polypeptides, compositions thereof, methods of purifying these polypeptides, and methods of using these polypeptides.
The growth of mammalian cells is tightly regulated by polypeptide growth factors. In the adult animal, most cells are metabolically active but are quiescent with regard to cell division. Under certain conditions, these cells can be stimulated to reenter the cell cycle and divide. As quiescent cells reenter the active growth and division phases of the cell cycle, a number of specific genes, the immediate early genes, are rapidly activated. Reentry to the active cell cycle is by necessity tightly regulated, since a breakdown of this control can result in uncontrolled growth, frequently recognized as cancer. Controlled reentry of particular cells into the growth phase is essential for such biological processes as angiogenesis (e.g., blood vessel growth and repair), chondrogenesis (e.g., skeletal development and prosthesis integration), oncogenesis (e.g., cancer cell metastasis and tumor neovascularization), and other growth-requiring processes.
Angiogenesis, the formation of new blood vessels from the endothelial cells of preexisting blood vessels, is a complex process which involves a changing profile of endothelial cell gene expression, associated with cell migration, proliferation, and differentiation. Angiogenesis begins with localized breakdown of the basement membrane of the parent vessel. In vivo, basement membranes (primarily composed of laminin, collagen type IV, nidogen/entactin, and proteoglycan) support the endothelial cells and provide a barrier separating these cells from the underlying stroma. The basement membrane also affects a variety of biological activities including cell adhesion, migration, and growth during development and differentiation.
Following breakdown of the basement membrane, endothelial cells migrate away from the parent vessel into the interstitial extracellular matrix (ECM), at least partially due to chemoattractant gradients. The migrating endothelial cells form a capillary sprout, which elongates. This elongation is the result of migration and proliferation of cells in the sprout. Cells located in the leading capillary tip migrate toward the angiogenic stimulus, but neither synthesize DNA nor divide. Meanwhile, behind these leading tip cells, other endothelial cells undergo rapid proliferation to ensure an adequate supply of endothelial cells for formation of the new vessel. Capillary sprouts then branch at their tips, the branches anastomose or join with one another to form a lumen, the basement membrane is reconstituted, and a vascular connection is established leading to blood flow.
Alterations in at least three endothelial cell functions occur during angiogenesis: 1) modulations of interactions with the ECM, which require alterations of cell-matrix contacts and the production of matrix-degrading proteolytic enzymes; 2) an initial increase and subsequent decrease in endothelial cell migration, effecting cell translocation towards an angiogenic stimulus; and 3) a transient increase in cell proliferation, providing cells for the growing and elongating vessel, with a subsequent return to the quiescent cell state once the vessel is formed. These three functions are realized by adhesive, chemotactic, and mitogenic interactions or responses, respectively. Therefore, control of angiogenesis requires intervention in three distinct cellular activities: 1) cell adhesion, 2) cell migration, and 3) cell proliferation. Another biological process involving a similar complex array of cellular activities is chondrogenesis.
Chondrogenesis is the cellular process responsible for skeletal organization, including the development of bone and cartilage. Chondrogenesis, like angiogenesis, involves the controlled reentry of quiescent cells into the growth phase of the cell cycle. The growth phase transition is associated with altered cell adhesion characteristics, changed patterns of cell migration, and transiently increased cell proliferation. Chondrogenesis involves the initial development of chondrogenic capacity (i.e., the proto-differentiated state) by primitive undifferentiated mesenchyme cells. This stage involves the production of chondrocyte-specific markers without the ability to produce a typical cartilage ECM. Subsequently, the cells develop the capacity to produce a cartilage-specific ECM as they differentiate into chondrocytes. Langille, Microscop. Res. and Tech. 28:455-469 (1994). Chondrocyte migration, adhesion, and proliferation then contribute to the development of bony, and cartilaginous, skeleton. Abnormal elaboration of the programmed development of cells participating in the process of chondrogenesis results in skeletal defects presenting problems that range from cosmetic concerns to life-threatening disorders.
Like angiogenesis and chondrogenesis, oncogenesis is characterized by changes in cell adhesion, migration, and proliferation. Metastasizing cancer cells exhibit altered adhesion and migration properties. Establishment of tumorous masses requires increased cell proliferation and the elaboration of the cellular properties characteristic of angiogenesis during the neovascularization of tumors.
Abnormal progression of angiogenesis or chondrogenesis, as well as mere progression of oncogenesis, substantially impairs the quality of life for afflicted individuals and adds to modern health care costs. The features common to these complex biological processes, comprising altered cell adhesion, migration, and proliferation, suggest that agents capable of influencing all three of these cellular activities would be effective in screening for, and modulating, the aforementioned complex biological processes. Although the art is aware of agents that influence individual cellular activities, e.g., integrins and selectins (cell adhesion), chemokines (cell migration), and a variety of growth factors or cytokines (cell proliferation), until recently no agent has been identified that exerts an influence over all three cellular activities in humans.
Murine Cyr61 (CYsteine-Rich protein) is a protein expressed in actively growing and dividing cells that may influence each of these three cellular activities. RNase protection analyses have shown that the gene encoding murine Cyr61, murine cyr61, is transcribed in the developing mouse embryo. O""Brien et al., Cell Growth and Diff. 3:645-654 (1992). In situ hybridization analysis showed that expression of cyr61 during mouse embryogenesis is closely correlated with the differentiation of mesenchymal cells, derived from ectoderm and mesoderm, into chondrocytes. In addition, cyr61 is expressed in the vessel walls of the developing circulatory system. These observations indicate that murine cyr61 is expressed during cell proliferation and differentiation, which are characteristics of expression of genes involved in regulatory cascades that control the cell growth cycle.
Further characterization of the Cyr61 polypeptide has been hampered by an inability to purify useful quantities of the protein. Efforts to purify Cyr61 in quantity by overexpression from either eukaryotic or prokaryotic cells typically fail. Yang, University of Illinois at Chicago, Ph.D. Thesis (1993). One problem associated with attempting to obtain useful quantities of Cyr61 is the reduction in mammalian growth rates induced by overexpression of Cyr61. Another problem with Cyr61 purification is that the cysteine-rich polypeptide, when expressed in bacterial cells using recombinant DNA techniques, is often found in insoluble protein masses. Nevertheless. Cyr61 has been characterized as a polypeptide of 349 amino acids, containing 39 cysteine residues, a hydrophobic putative N-terminal signal sequence, and potential N-linked glycosylation sites (Asn28 and Asn225). U.S. Pat. No. 5,408,040 at column 3, lines 41-54, Grotendorst et al., incorporated herein by reference (the ""040 Patent).
Recently, proteins related to Cyr61 have been characterized. For example, a human protein, Connective Tissue Growth Factor (CTGF), has been identified. (See ""040 Patent). CTGF is expressed in actively growing cells such as fibroblasts and endothelial cells (""040 Patent, at column 5, lines 62-64), an expression pattern shared by Cyr61. In terms of function, CTGF has been described as a protein growth factor because its primary biological activity has been alleged to be its mitogenicity (""040 Patent, at column 2, lines 25-27 and 53-55). In addition, CTGF reportedly exhibits chemotactic activity. ""040 Patent, at column 2, lines 56-59. In terms of structure, the polynucleotide sequence encoding CTGF, and the amino acid sequence of CTGF, have been published. ""040 Patent, SEQ ID NO:7 and SEQ ID NO:8, respectively.
Another apparently related protein is the mouse protein Fisp12 (FIbroblast Secreted Protein). Fisp12 has been subjected to amino acid sequence analysis, revealing a primary structure that is rich in cysteines. Ryseck et al., Cell Growth and Diff. 2:225-233 (1991), incorporated herein by reference. The protein also possesses a hydrophobic N-terminal sequence suggestive of the signal sequence characteristic of secreted proteins.
Sequence analyses involving Cyr61, Fisp12, CTGF, and other proteins, have contributed to the identification of a family of cysteine-rich secreted proteins. Members of the family share similar primary structures encoded by genes exhibiting similar sequences. Each of the proteins in this emerging family is further characterized by the presence of a hydrophobic N-terminal signal sequence and 38 cysteine residues in the secreted forms of the proteins. Members of the family identified to date include the aforementioned Cyr61 (human and mouse), Fisp12 (mouse), and CTGF (the human ortholog of Fisp12), as well as CEF10 (chicken), and Nov (avian).
One of several applications for a purified protein able to affect cell adhesion, migration, and proliferation properties involves the development of stable, long term ex vivo hematopoietic stem cell cultures. Patients subjected to high-dose chemotherapy have suppressed hematopoiesis; expansion of stem cells, their maturation into various hematopoietic lineages, and mobilization of mature cells into circulating blood routinely take many weeks to complete. For such patients, and others who need hematopoietic cell transplantation, introduction into those patients of autologous stem cells that have been manipulated and expanded in culture is advantageous. Such hermatopoietic stem cells (HSC) express the CD34 stem cell antigen, but do not express lineage commitment antigens. These cells can eventually give rise to all blood cell lineages (e.g., erythrocytes, lymphocytes, and myelocytes).
Hematopoietic progenitor cells that can initiate and sustain long term cultures (i.e., long term culture system-initiating cells or LTC-IC) represent a primitive population of stem cells. The frequency of LTC-IC has been estimated at only 1-2 per 104 cells in normal human marrow and only about 1 per 50-100 cells in a highly purified CD34+ subpopulation. Thus, it would be useful to have methods and systems for long term cell culture that maintain and expand primitive, pluripotent human HSC to be used for repopulation of the hematopoietic system in vivo.
Cell culture models of hematopoiesis have revealed a multitude of cytokines that appear to play a role in the hematopoietic process, including various colony stimulating factors, interleukins, stem cell factor, and the c-kit ligand. However, in ex vivo cultures, different combinations of these cytokines favor expansion of different sets of committed progenitors. For example, a factor in cord blood plasma enhanced expansion of granulocyte-erythroid-macrophage-megakaryocyte colony forming unit (CFU-GEMM) progenitors, but expansion in these cultures favored the more mature subsets of cells. Therefore, it has been difficult to establish a culture system that mimics in vivo hematopoiesis.
An HSC culture system should maintain and expand a large number of multi- or pluripotent stem cells capable of both long term repopulation and eventual lineage commitment under appropriate induction. However, in most ex vivo culture systems, the fraction of the cell population comprised of LTC-IC decreases steadily with continued culturing, often declining to 20% of their initial level after several weeks, as the culture becomes populated by more mature subsets of hematopoietic progenitor cells that are no longer pluripotent. Moreover, the proliferative capacity exhibited by individual LTC-IC may vary extensively. Thus, a need exists in the art for HSC culture systems comprising biological agents that maintain or promote the pluripotent potential of cells such as LTC-IC cells. In addition to a role in developing ex vivo HSC cultures, biological agents affecting cell adhesion, migration, and proliferation are useful in a variety of other contexts.
Proteins that potentiate the activity of mitogens but have no mitogenic activity themselves may play important roles as signalling molecules in such processes as hematopoiesis. Moreover, these signalling proteins could also serve as probes in the search for additional mitogens, many of which have not been identified or characterized. Several biological factors have been shown to potentiate the mitogenic activity of other factors, without being mitogenic themselves. Some of these potentiators are associated with the cell surface and/or extracellular matrix. Included in this group are a secreted basic Fibroblast Growth Factor-binding protein (bFGF-binding protein), the basal lamina protein perlecan, and the Human Immunodeficiency Virus-1 TAT protein, each protein being able to promote bFGF-induced cell proliferation and angiogenesis. Also included in this group of mitogen potentiators are thrombospondin, capable of activating a latent form of Transforming Growth Factor-xcex2, and an unidentified secreted growth-potentiating factor from vascular smooth muscle cells (Nakano et al., J. Biol. Chem. 270:5702-5705 [1995]), the latter factor being required for efficient activation of Epidermal Growth Factor- or thrombin-induced DNA synthesis. Further, the B cell stimulatory factor-1/interleukin-4, a T cell product with no demonstrable mitogenic activity, is able to 1) enhance the proliferative response of granulocyte-macrophage progenitors to granulocyte-colony stimulating factor, 2) enhance the proliferative response of erythroid progenitors to erythropoietin, and 3) together with erythropoietin, induce colony formation by multipotent progenitor cells. Similarly, interleukin-7 enhanced stem cell factor-induced colony formation by primitive murine bone marrow progenitors, although interleukin-7 had no proliferative effect by itself. In addition, lymphocyte growth enhancing factor (LGEF) was found to enhance mitogen-stimulated human peripheral blood lymphocyte (PBL) or purified T cell proliferation in a dose-dependent fashion. LGEF alone did not stimulate PBL or T cell proliferation.
Therefore, a need continues to exist for biological agents capable of exerting a concerted and coordinated influence on one or more of the particularized functions collectively characterizing such complex biological processes as angiogenesis, chondrogenesis, and oncogenesis. In addition, a need persists in the art for agents contributing to the reproduction of these in vivo processes in an ex vivo environment, e.g., the development of HSC cultures. Further, there continues to be a need for tools to search for the remaining biological components of these complex processes, e.g., mitogen probes, the absence of which impedes efforts to advantageously modulate and thereby control such processes.
The present invention provides extracellular matrix (ECM) signalling molecule-related materials and methods. In particular, the present invention is directed to polynucleotides encoding ECM signalling molecules and fragments or analogs thereof, ECM signalling molecule-related polypeptides and fragments, analogs, and derivatives thereof, methods of producing ECM signalling molecules, and methods of using ECM signalling molecules.
One aspect of the present invention relates to a purified and isolated polypeptide comprising an ECM signalling molecule. The polypeptides according to the invention retain at least one biological activity of an ECM signalling molecule, such as the ability to stimulate cell adhesion, cell migration, or cell proliferation; the ability to modulate angiogenesis, chondrogenesis, or oncogenesis; immunogenicity or the ability to elicit an immune response; and the ability to bind to polypeptides having specific binding sites for ECM signalling molecules, including antibodies and integrins. The polypeptides may be native or recombinant molecules. Further, the invention comprehends full-length ECM signalling molecules, and fragments thereof. In addition, the polypeptides of the invention may be underivatized, or derivatized in conformity with a native or non-native derivatization pattern. The invention further extends to polypeptides having a native or naturally occurring amino acid sequence, and variants (i.e., polypeptides having different amino acid sequences), analogs (i.e., polypeptides having a non-standard amino acid or other structural variation from the conventional set of amino acids) and homologs (i.e., polypeptides sharing a common evolutionary ancestor with another polypeptide) thereof. Polypeptides that are covalently linked to other compounds, such as polyethylene glycol, or other proteins or peptides, i.e. fusion proteins, are contemplated by the invention.
Exemplary ECM signalling molecules include mammalian Cyr61, Fisp12, and CTGF polypeptides. Beyond ECM signalling molecules, the invention includes polypeptides that specifically bind an ECM signalling molecule of the invention, such as the aforementioned antibody products. A wide variety of antibody products fall within the scope of the invention, including polyclonal and monoclonal antibodies, antibody fragments, chimeric antibodies, CDR-grafted antibodies, xe2x80x9chumanizedxe2x80x9d antibodies, and other antibody forms known in the art. Other molecules such as peptides, carbohydrates or lipids designed to bind to an active site of the ECM molecules thereby inhibiting their activities are also contemplated by the invention. However molecules such as peptides that enhance or potentiate the activities of ECM molecule are also within the scope of the invention. The invention further extends to a pharmaceutical composition comprising a biologically effective amount of a polypeptide and a pharmaceutically acceptable adjuvant, diluent or carrier, according to the invention. A xe2x80x9cbiologically effective amountxe2x80x9d of the biomaterial is an amount that is sufficient to result in a detectable response in the biological sample when compared to a control lacking the biomaterial.
Another aspect of the invention relates to a purified and isolated polynucleotide comprising a sequence that encodes a polypeptide of the invention. A polynucleotide according to the invention may be DNA or RNA, single- or double-stranded, and may be may purified and isolated from a native source, or produced using synthetic or recombinant techniques known in the art. The invention also extends to polynucleotides encoding fragments, analogs (i.e., polynucleotides having a non-standard nucleotide), homologs (i.e., polynucleotides having a common evolutionary ancestor with another polynucleotide), variants (i.e., polynucleotides differing in nucleotide sequence), and derivatives (i.e., polynucleotides differing in a structural manner that does not involve the primary nucleotide sequence) of ECM molecules. Vectors comprising a polynucleotide according to the invention are also contemplated. In addition, the invention comprehends host cells transformed or transfected with a polynucleotide or vector of the invention.
Other aspects of the invention relate to methods for making or using the polypeptides and/or polynucleotides of the invention. A method for making a polypeptide according to the invention comprises expressing a polynucleotide encoding a polypeptide according to the present invention in a suitable host cell and purifying the polypeptide. Other methods for making a polypeptide of the invention use techniques that are known in the art, such as the isolation and purification of native polypeptides or the use of synthetic techniques for polypeptide production. In particular, a method of purifying an ECM signalling molecule such as human Cyr61 comprises the steps of identifying a source containing human Cyr61, exposing the source to a human Cyr61-specific biomolecule that binds Cyr61 such as an anti-human Cyr61 antibody, and eluting the human Cyr61 from the antibody or other biomolecule, thereby purifying the human Cyr61.
Another aspect of the invention is a method of screening for a modulator of angiogenesis comprising the steps of: (a) contacting a first biological sample capable of undergoing angiogenesis with a biologically effective (i.e., angiogenically effective) amount of an ECM signalling molecule-related biomaterial and a suspected modulator (inhibitor or potentiator); (b) separately contacting a second biological sample with a biologically effective amount of an ECM signalling molecule-related biomaterial, thereby providing a control; (c) measuring the level of angiogenesis resulting from step (a) and from step (b); and (d) comparing the levels of angiogenesis measured in step (c), whereby a modulator of angiogenesis is identified by its ability to alter the level of angiogenesis when compared to the control of step (b). The modulator may be either a potentiator or inhibitor of angiogenesis and the ECM signalling molecule-related biomaterial includes, but is not limited to, Cyr61, and fragments, variants, homologs, analogs, derivatives, and antibodies thereof.
The invention also extends to a method of screening for a modulator of angiogenesis comprising the steps of: (a) preparing a first implant comprising Cyr61 and a second implant comprising Cyr61 and a suspected modulator of Cyr61 angiogenesis; (b) implanting the first implant in a first cornea of a test animal and the second implant in a second cornea of the test animal; (c) measuring the development of blood vessels in the first and second corneas; and (d) comparing the levels of blood vessel development measured in step (c), whereby a modulator of angiogenesis is identified by its ability to alter the level of blood vessel development in the first cornea when compared to the blood vessel development in the second cornea.
Another aspect of the invention relates to a method of screening for a modulator of chondrogenesis comprising the steps of: (a) contacting a first biological sample capable of undergoing chondrogenesis with a biologically effective (e.g. chondrogenically effective) amount of an ECM signalling molecule-related biomaterial and a suspected modulator; (b) separately contacting a second biological sample capable of undergoing chondrogenesis with a biologically effective amount of an ECM signalling molecule-related biomaterial, thereby providing a control; (c) measuring the level of chondrogenesis resulting from step (a) and from step (b); and (d) comparing the levels of chondrogenesis measured in step (c), whereby a modulator of chondrogenesis is identified by its ability to alter the level of chondrogenesis when compared to the control of step (b). The modulator may be either a promoter or an inhibitor of chondrogenesis; the ECM signalling molecules include those defined above and compounds such as mannose-6-phosphate, heparin, and tenascin.
The invention also relates to an in vitro method of screening for a modulator of oncogenesis comprising the steps of: (a) inducing a first tumor and a second tumor; (b) administering a biologically effective amount of an ECM signalling molecule-related biomaterial and a suspected modulator to the first tumor; (c) separately administering a biologically effective amount of an ECM signalling molecule-related biomaterial to the second tumor, thereby providing a control; (d) measuring the level of oncogenesis resulting from step (b) and from step (c); and (e) comparing the levels of oncogenesis measured in step (d), whereby a modulator of oncogenesis is identified by its ability to alter the level of oncogenesis when compared to the control of step (c). Modulators of oncogenesis contemplated by the invention include inhibitors of oncogenesis. Tumors may be induced by a variety of techniques including, but not limited to, the administration of chemicals, e.g., carcinogens, and the implantation of cancer cells. A related aspect of the invention is a method for treating a solid tumor comprising the step of delivering a therapeutically effective amount of a Cyr61 inhibitor to an individual, thereby inhibiting the neovascularization of the tumor. Inhibitors include, but are not limited to, inhibitor peptides such as peptides having the xe2x80x9cRGDxe2x80x9d motif, and cytotoxins, which may be free or attached to molecules such as Cyr61.
Yet another aspect of the invention is directed to a method of screening for a modulator of cell adhesion comprising the steps of: (a) preparing a surface compatible with cell adherence; (b) separately placing first and second biological samples capable of undergoing cell adhesion on the surface; (c) contacting a first biological sample with a suspected modulator and a biologically effective amount of an ECM signalling molecule-related biomaterial selected from the group consisting of a human Cyr61, a human Cyr61 fragment, a human Cyr61 analog, and a human Cyr61 derivative; (d) separately contacting a second biological sample with a biologically effective amount of an ECM signalling molecule-related biomaterial selected from the group consisting of a human Cyr61, a human Cyr61 fragment, a human Cyr61 analog, and a human Cyr61 derivative, thereby providing a control; (e) measuring the level of cell adhesion resulting from step (c) and from step (d); and (f) comparing the levels of cell adhesion measured in step (e), whereby a modulator of cell adhesion is identified by its ability to alter the level of cell adhesion when compared to the control of step (d).
The invention also extends to a method of screening for a modulator of cell migration comprising the steps of: (a) forming a gel matrix comprising Cyr61 and a suspected modulator of cell migration; (b) preparing a control gel matrix comprising Cyr61; (c) seeding endothelial cells capable of undergoing cell migration onto the gel matrix of step (a) and the control gel matrix of step (b); (d) incubating the endothelial cells; (e) measuring the levels of cell migration by inspecting the interior of the gel matrix and the control gel matrix for cells; (f) comparing the levels of cell migration measured in step (e), whereby a modulator of cell migration is identified by its ability to alter the level of cell migration in the gel matrix when compared to the level of cell migration in the control gel matrix. The endothelial cells include, but are not limited to, human cells, e.g., human microvascular endothelial cells. The matrix may be formed from gelling materials such as Matrigel, collagen, or fibrin or combinations thereof.
Another aspect of the invention is directed to an in vitro method of screening for cell migration comprising the steps of: (a) forming a first gelatinized filter and a second gelatinized filter, each filter having two sides; (b) contacting a first side of each the filter with endothelial cells, thereby adhering the cells to each the filter; (c) applying an ECM signalling molecule and a suspected modulator of cell migration to a second side of the first gelatinized filter and an ECM signalling molecule to a second side of the second gelatinized filter; (d) incubating each the filter; (e) detecting cells on the second side of each the filter, and (f) comparing the presence of cells on the second side of the first gelatinized filter with the presence of cells on the second side of the second gelatinized filter, whereby a modulator of cell migration is identified by its ability to alter the level of cell migration measured on the first gelatinized filter when compared to the cell migration measured on the second gelatinized filter. The endothelial cells are defined above. The ECM signalling molecules extend to human Cyr61 and each of the filters may be placed in apparatus such as a Boyden chamber, including modified Boyden chambers.
The invention also embraces an in vivo method of screening for a modulator of cell migration comprising the steps of: (a) removing a first central portion of a first biocompatible sponge and a second central portion of a second biocompatible sponge; (b) applying an ECM signalling molecule and a suspected modulator to the first central portion and an ECM signalling molecule to the second central portion; (c) reassociating the first central portion with said first biocompatible sponge and said second central portion with the second biocompatible sponge; (d) attaching a first filter to a first side of the first biocompatible sponge and a second filter to a second side of the first biocompatible sponge; (e) attaching a third filter to a first side of the second biocompatible sponge and a fourth filter to a second side of the second biocompatible sponge; (f) implanting each of the biocompatible sponges, each biocompatible sponge comprising the central portion and the filters, in a test animal; (e) removing each the sponge following a period of incubation; (f) measuring the cells found within each of the biocompatible sponges; and (g) comparing the presence of cells in the first biocompatible sponge with the presence of cells in the second biocompatible sponge, whereby a modulator of cell migration is identified by its ability to alter the level of cell migration measured using the first biocompatible sponge when compared to the cell migration measured using the second biocompatible sponge. ECM signalling molecules include, but are not limited to, human Cyr61; the ECM signalling molecule may also be associated with Hydron. In addition, the in vivo method of screening for a modulator of cell migration may include the step of providing a radiolabel to the test animal and detecting the radiolabel in one or more of the sponges.
Another aspect of the invention relates to a method for modulating hemostasis comprising the step of administering an ECM signalling molecule in a pharmaceutically acceptable adjuvant, diluent or carrier. Also, the invention extends to a method of inducing wound healing in a tissue comprising the step of contacting a wounded tissue with a biologically effective amount of an ECM signalling molecule, thereby promoting wound healing. The ECM signalling molecule may be provided in the form of an ECM signalling molecule polypeptide or an ECM signalling molecule nucleic acid, e.g., using a gene therapy technique. For example. the nucleic acid may comprise an expression control sequence operably linked to an ECM signalling molecule which is then introduced into the cells of a wounded tissue. The expression of the coding sequence is controlled, e.g., by using a tissue-specific promoter such as the K14 promoter operative in skin tissue to effect the controlled induction of wound healing. The nucleic acid may include a vector such as a Herpesvirus, an Adenovirus, an Adeno-associated Virus, a Cytomegalovirus, a Baculovirus, a retrovirus, and a Vaccinia Virus. Suitable wounded tissues for treatment by this method include, but are not limited to, skin tissue and lung epithelium. A related method comprises administering a biologically effective amount of an ECM signalling molecule, e.g. Cyr61, to an animal to promote organ regeneration. The impaired organ may be the result of trauma, e.g. surgery, or disease. Another method of the invention relates to improving the vascularization of grafts, e.g., skin grafts. Another method of the invention is directed to a process for promoting bone implantation, including bone grafts. The method for promoting bone implantation comprises the step of contacting a bone implant or receptive site with a biologically effective (i.e., chondrogenically effective) amount of an ECM signalling molecule. The contacting step may be effected by applying the ECM signalling molecule to a biocompatible wrap such as a biodegradable gauze and contacting the wrap with a bone implant, thereby promoting bone implantation. The bone implants comprise natural bones and fragments thereof, as well as inanimate natural and synthetic materials that are biocompatible, such as prostheses. In addition to direct application of an ECM signalling molecule to a bone, prosthesis, or receptive site, the invention contemplates the use of matrix materials for controlled release of the ECM signalling molecule, in addition to such application materials as gauzes.
Yet another aspect of the invention relates to a method of screening for a modulator of cell proliferation comprising the steps of: (a) contacting a first biological sample capable of undergoing cell proliferation with a suspected modulator and a biologically effective (i.e., mitogenically effective) amount of an ECM signalling molecule-related biomaterial selected from the group consisting of a human Cyr61, a human Cyr61 fragment, a human Cyr61 analog, and a human Cyr61 derivative; (b) separately contacting a second biological sample capable of undergoing cell proliferation with a biologically effective amount of an ECM signalling molecule-related biomaterial selected from the group consisting of a human Cyr61, a human Cyr61 fragment, a human Cyr61 analog, and a human Cyr61 derivative, thereby providing a control; (c) incubating the first and second biological samples; (d) measuring the level of cell proliferation resulting from step (c); and (e) comparing the levels of cell proliferation measured in step (d), whereby a modulator of cell proliferation is identified by its ability to alter the level of cell adhesion when compared to the control of step (b).
Also comprehended by the invention is a method for expanding a population of undifferentiated hematopoietic stem cells in culture, comprising the steps of: (a) obtaining hermatopoietic stem cells from a donor; and (b) culturing said cells tinder suitable nutrient conditions in the presence of a biologically effective (i.e., hematopoietically effective) amount of Cyr61.
Another method according to the invention is a method of screening for a mitogen comprising the steps of: (a) plating cells capable of undergoing cell proliferation; (b) contacting a first portion of the cells with a solution comprising Cyr61 and a suspected mitogen; (c) contacting a second portion of the cells with a solution comprising Cyr61, thereby providing a control; (c) incubating the cells; (d) detecting the growth of the first portion of cells and the second portion of the cells; and (e) comparing growth of the first and second portions of cells, whereby a mitogen is identified by its ability to induce greater growth in the first portion of cells when compared to the growth of the second portion of cells. The cells include, but are not limited to, endothelial cells and fibroblast cells. Further, the method may involve contacting the cells with a nucleic acid label, e.g., [3H]-thymidine, and detecting the presence of the label in the cells. Another method relates to improving tissue grafting, comprising administering to an animal a quantity of Cyr61 effective in improving the rate of neovascularization of a graft.
Numerous additional aspects and advantages of the present invention will be apparent upon consideration of the following drawing and detailed description. | {
"pile_set_name": "USPTO Backgrounds"
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Famously referred to by National Geographic as “the most dangerous eight seconds in sports,” bull riding pits an athlete 20 one-on-one against a bull 24 weighing as much as 2000 pounds in a showdown so hazardous that one or two bull riders 20 per year lose their lives to the competition. Notwithstanding the ever present peril, however, and much to the excitement of nearly two million annual live event attendees and another 100 million annual television viewers, bull riders 20 are spurred on by the thrill of the action, and the desire to test their skills, tenacity and daring against the mighty bulls 24, to continue to participate in the sport. With the sport likely only to increase in fan popularity and rider participation, improvements in rider safety become ever more important.
To this end, promoters of bull riding have gone to great lengths to provide the bull riders 20 with additional protection from the bulls. For example, improved helmets and a specially designed protective vest 23 have greatly contributed to a reduced injury rate. Unfortunately, however, one danger that persists notwithstanding its often tragic consequences is the risk that the bull rider 20 will be unable to successfully free his or her riding hand 21 from the bull rope 29 during dismount, especially in the case of being bucked off from the bull 24. When such a “hang up” happens, the bull rider 20 is almost never able to reach the bull rope 29 with his or her free hand 22 and, as a result is completely dependent on the bullfighters or horsemen for what is very likely lifesaving assistance. Until the bullfighters and horsemen are able to reach the bull 24 and gain control over the bull rope 29, however, the bull rider 20 is in grave danger of being trampled by the bull 24 or slammed into the arena fence or bull chutes. In any of these situations, serious injury or death is a very probable result.
With the shortcomings of the prior art clearly in mind, it is therefore an overriding object of the present invention to provide a method and apparatus through which a harness may be quickly and reliably removed from an animal, removal therefrom being possible through remote control. | {
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The present invention generally relates to the controlled application of flux. The present invention is particularly related to the application of flux for the selectability of the type of deposition, either spray or droplet(s), the location of the deposition and the selected amount of deposition. Even more particularly, the present invention is related to the dispensing apparatus which can selectively provide either microdeposits or finely controlled atomization in a single device while being able to vary deposition properties rapidly during the application process. In addition, delivery of the flux to the dispensing apparatus is precisely coordinated with the dispense parameters.
This invention pertains to a method and apparatus for controlling the dispensing of fluid materials, and more particularly to a method and apparatus for controlling the dispensing of flux on an electronic assembly such as a printed circuit board, or on components used thereon.
The invention is particularly applicable to dispensing flux with a solids content less than 15% and a viscosity of less than 100 cps, and more specifically, a viscosity less than 50 cps. However, it will be appreciated that the invention has broader application and may be advantageously employed with other types of fluxes. In the assembly of a printed circuit board (PCB) the soldering process is one of the most critical steps. Soldering has traditionally been done with a process known as wave soldering. Known structures and methods for applying flux to a printed circuit board prior to the wave soldering step include liquid wave, foaming, brushing or spraying as described, for example in U.S. Pat. No. 5,328,085.
The disadvantages of each of these processes are also described in U.S. Pat. No. 5,328,085. While the prior art has reduced many of the problems of applying flux there are new requirements for more selective flux application, greater control of deposition and increased through-hole penetration of the flux. In addition, there is now a desire to flux only selected areas with a thin application of flux. These needs exist in traditional wave soldering equipment and in newer selective soldering applications.
Due to the decreased need for through-hole components, many wave soldering manufacturers are now using pallets with cut-out regions for soldering which are referred to as aperture wave solder pallets. The solder wave still contacts the complete bottom surface of the pallet but only comes in direct contact with the PCB through the open areas in the pallet. The need is for flux application that can either 1) apply flux only to the exposed areas of the board or to 2) apply flux at required quantities in the exposed areas and at a reduced amount over the rest of the bottom surface of the pallet. A small layer of flux on the pallet can extend the life of the pallet so a reduced level of flux on the pallet is desired.
In addition, there is a need for better penetration of flux into the holes in the boards while not applying excess flux or leaving a residual amount of flux at the interface of the pallets and PCB.
Also, a new approach to soldering PCBs called selective soldering requires discrete programmable amounts of flux to be applied to the PCB. Selective soldering only solders the through-hole areas and therefore only those selected areas need to have flux applied to them. This approach reduces the amount of flux used and, more importantly, can restrict the heat exposure associated with solder temperatures to only those areas on the board that require wave soldering. Current methods include stationary spray guns positioned under a template which blocks the flux where it is not needed or a programmed spray gun which moves to locations but again applies flux through the open area of a template. Both of these methods require 1) extensive maintenance due to the excess flux produced, 2) extensive tooling for each board, 3) additional setup time for changing tooling for each new board lot, and 4) inconsistencies in setting up the multiple spray guns for each discrete location. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to circuitry used for interfacing different families of logic circuits, and more particularly, to an emitter coupled logic (ECL) to bipolar complementary metal oxide semiconductor (BiCMOS) and complementary metal oxide semiconductor (CMOS) translator.
2. Description of the Related Art
Situations often arise where certain portions of a digital system require high-speed logic gates while other portions of the system can tolerate low-speed logic gates. In these situations, it is advantageous to use more than one logic family because, where low-speed can be tolerated, a low-speed family such as CMOS will dissipate less power than a high-speed family such as ECL.
When more than one logic family is used in a system, it is necessary to take into account the fact that the output of one family may not be compatible with the input of another. In order to properly transfer data between different logic families, special interfacing circuits, or "translators," can be used to convert the logic signals generated by one family into signals which can be understood by a different family.
FIG. 1 illustrates a block diagram of a conventional ECL-to-CMOS translator 20. The translator 20 converts ECL level signals to CMOS level signals. During operation, an ECL level signal is received at node 22. The dynamic signal range for ECL logic is about -1.7 to -1.4 Volts for logical low ("0") and about -0.9 to -0.8 Volts for logical high ("1"). An ECL receiver circuit 24 converts the received ECL signal to a pair of differential ECL level signals (i.e., complementary ECL signals). The differential ECL signals are carried by lines 26 and 28 to a translator circuit 30. The translator circuit 30 converts the differential ECL level signals to a single CMOS level signal. The single CMOS level signal is output at node 32. The dynamic signal range for CMOS logic is about -5.0 to -4.8 Volts for logical low ("0") and about -0.4 to 0.0 Volts for logical high ("1").
FIG. 2 illustrates a circuit implementation of the conventional ECL-to-CMOS translator 20 of FIG. 1. The ECL receiver circuit 24 is basically a current-mode logic (CML) gate, and its operation is well known in the art. Specifically, bipolar transistor Q1, which receives the ECL input signal at its base, is connected in emitter follower configuration to a voltage-comparator circuit which is constructed from bipolar transistors Q2 and Q3 and resistors R1 and R2. Voltage comparator circuits are the basic components of ECL and CML gates. Lines 26 and 28, which carry the pair of differential ECL signals, are connected to the collectors of transistors Q3 and Q2, respectively.
The translator circuit 30 includes p-channel MOSFET transistors MP1 through MP3, n-channel MOSFET transistors MN1 through MN5, and bipolar transistors Q4 and Q5. Transistor Q4 has its collector connected to a first voltage source which supplies a voltage roughly equal to that of a CMOS logical high, i.e., about 0.0 Volts. Transistor Q5 has its emitter connected to a second voltage source which supplies a voltage roughly equal to that of a CMOS logical low, i.e., about -5.2 Volts. The emitter of transistor Q4 and the collector of transistor Q5 are connected together and form output node 32.
Translator circuit 30 generates CMOS level signals on output node 32 by switching only one of transistors Q4 and Q5 on at a time. When transistor Q4 is switched on, transistor Q5 is off, and output node 32 is pulled up to a CMOS logical high, i.e., about -0.4 Volts. When transistor Q5 is switched on, transistor Q4 is off, and output node 32 is pulled down to a CMOS logical low, i.e., about -4.8 Volts.
The pair of differential ECL signals are received at the gates of transistors MP1 and MP2 via lines 26 and 28, respectively. Transistors MP1 through MP3 and MN1 through MN5, in response to the differential ECL signals, switch transistors Q4 and Q5 on and off. Specifically, when line 26 carries a low signal, and line 28 carries a high signal, transistor MP1 switches on and transistor MP2 switches off. Because transistor MP1 is on, transistor MN2 switches on and causes the gates of transistors MP3, MN3, and MN4 to be pulled low. Transistor MP3 switches on and causes the base of transistor Q4 to be pulled high, thus, switching transistor Q4 on. Because transistor Q4 is on, a high signal is received at the gate of transistor MN5 which switches transistor MN5 on. The base of transistor Q5 is pulled low which switches transistor Q5 off.
conversely, when line 26 carries a high signal, and line 28 carries a low signal, transistor MP1 switches off and transistor MP2 switches on. Because transistor MP2 is on, the gates of transistors MP3, MN3 and MN4 are pulled high. Transistor MN3 switches on which pulls the base of transistor Q4 low, thus, switching transistor Q4 off. Transistor MN5 remains off which permits transistor Q5 to switch on.
The conventional ECL-to-CMOS translator 20 of FIGS. 1 and 2 has a number of deficiencies. First, due to the large number of transistors employed, the translator 20 tends to dissipate a large amount of power. Second, the large number of transistors require a period of time to complete the switching operation, which is too slow for many modern applications. Finally, the large number of transistors makes the circuit impractical for modern high density products; there are often space and layout problems which render the manufacture of the circuit economically unfeasible.
Thus, there is a need for an ECL-to-CMOS translator which dissipates less power, has fewer components, and has higher speed than conventional translators. | {
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Vee-type internal combustion engines include at least two cylinders arranged in a vee-type configuration, each cylinder being rotated a transverse angle from a vertical engine centerline, in an amount equal to one half of a bank angle. For example, a conventional vee-type internal combustion engine may comprise a first bank which comprises a first plurality of in-line cylinders and a second bank which comprises a second plurality of in-line cylinders, each bank extending in the direction of a longitudinal axis which extends from one end of the internal combustion engine to the opposite end thereof, the cylinders in opposite banks forming a vee-shape configuration. In order to provide serviceability, a conventional cylinder liner having a flange is inserted into each cylinder. Each liner flange is square with a respective cylinder bore, and the engine block and cylinder head mate with opposite surfaces of each liner flange to hold it in place. One or more conventional gaskets are positioned between the engine block and cylinder head to provide the usual sealing.
In designing a vee-type internal combustion engine, it is desirable to provide a structure which satisfies performance objectives and yet is relatively compact. For example, providing a narrow vee-type engine by reducing cylinder spacing in the direction of the longitudinal axis of the engine, would increase engine compactness. However, in vee-type engines, various considerations tend to limit. increasing the degree of compactness obtainable. For example, designing a cylinder head for use in a narrow vee-type internal combustion engine presents various problems. The use of an individual head for each cylinder is not desirable since it would be necessary to provide more than one head configuration. Further, an individual head pattern would create poor head bolt location choices. In addition, exhaust passages on each alternating head would be very long thereby contributing adversely to heat exchange characteristics. In the alternative, a cylinder head could be provided adjacent each bank of the engine, but such a configuration would be contrary to the objective of engine compactness in that two exhaust manifolds would be required. Further, milling of separate firedecks for each bank is generally not possible because the cylinder bores overlap into respective opposite firedecks. For modern diesel engines having direct fuel injection, however, it is desirable to orient each cylinder head firedeck within the combustion chamber so that the firedeck is perpendicular to the centerline of the cylinder, and to have the fuel injection nozzle located and oriented along the cylinder centerline. A full length, one piece cylinder head is also not desirable since the use of cylinder liners will require liner counterbores in the head and engine block, and in such a configuration dimensional variations that adversely affect compression seal load distribution become a problem.
A further consideration is that in prior art vee-type internal combustion engines, the engine exhaust port passages are typically coupled to an exhaust manifold at one or more interface surfaces which are parallel to the horizontal axis of the engine block. This feature in combination with conventional valve and intake port patterns effects a configuration which defines lengthy exhaust port passages which provide less than optimum heat transfer characteristics. In addition, in considering assembling vee-type internal combustion engines, problems exist relating to the need to compensate for tolerances of, and equalization of load distribution between, paired cylinder liner flanges. Further, while it is desirable to shorten exhaust passages to improve heat exchange characteristics, it is also necessary for the air induction system to be uniform for each cylinder so that the same swirl characteristics exist for all cylinders. In considering possible cylinder head configurations which address all of the foregoing concerns, it is also necessary to provide an exhaust and intake port pattern which satisfactorily accommodates pushrod and other valve operating mechanisms, head hole locations and cooling water jacket design. All of these considerations present problems in the manufacture of a head for a narrow vee-type internal combination engine. | {
"pile_set_name": "USPTO Backgrounds"
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Heretofore the detection of lithium in animal organs has been achieved only by post mortem specimens preferred in-vivo. This type of study of lithium level in different tissues and particularly in the brain is reported in 1976 by M. A. Spirites in "Pharmaceutical Biochemistry and Behavior", Volume 5, pages 143 to 147 and in 1980 by M. Thellier et al., in "Nature", Volume 283, pages 299 to 302. In view of use of lithium clinically for the treatment of mania and its effect on attenuation of manic and depressive episodes, it is important to be able to measure in-vivo the amount of lithium in body tissues and organs (in particular the brain and kidney).
Because of long term clinical administration of lithium salts and side effects, it is essential to monitor the action on the brain and any possible kidney overload or damage.
In connection with in-vivo measurements of humans there are many problems to be resolved to find a method that is acceptable as a procedural measure, particularly in view of low concentrations of lithium in the form of lithium salts resident in the body, the sensitiveness of the brain area, the inability to take specimens, etc. Also the accuracy of measurement of small concentrations of the lithium without serious interruption of life processes and thus necessarily by indirect methods presents another set of problems. Furthermore, the time it takes to ascertain the measurements is critical, in order to make them relate to the clinical effects and to investigate adequacy of doses, etc.
Thus, the objectives of this invention are to resolve the foregoing problems and to provide an in-vivo measurement of lithium concentrations in particularly the human body with enough accuracy to advance the clinical and therapeutic usage thereof.
The determination of lithium in various materials by the neutron activation method using the .sup.6 Li(n,.alpha.)T reaction has been reported by B. P. Zverev et al., in Soviet Atomic Energy (U.S.A.), Vol. 32, No. 1, Jan. 1972, pp. 35-37. H. I. Kallmann et al., 2,288,717 --July 7, 1942 also teaches liberation of tritium from lithium isotopes by neutron irradiation for forming images to thus show the nature of the neutron beam irradiation pattern.
However, there is no known method of in-vivo determination of lithium present in animal tissues and organs prior to this invention. | {
"pile_set_name": "USPTO Backgrounds"
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A polymer electrolyte fuel cell (PEFC) is a device for obtaining electric energy by causing a hydrogen gas provided as a fuel and oxygen provided as an oxidizer to react with each other. A unit cell formed as this fuel cell is constituted by a membrane electrode assembly (MEA) which is formed of a pair of porous electrodes (porous supporting layer+catalyst layer) are opposed to each other with a polymer electrolyte membrane interposed therebetween, and which is sandwiched between a pair of separators in each of which a channel for supplying a fuel or an oxidizer is formed. Unit cells formed in this way are stacked to be used as a stacked-cell battery. Various uses of such fuel cells as power sources for use on vehicles, fixed use and portable/mobile use at an operating temperature of about 80° C. are being expected. The electrode reaction is shown below.Anode: H2→2H++2e−Cathode: 2H++1/2O2+2e−→H2O (Formula 1)
At the anode (fuel pole), a fuel such as hydrogen or alcohol is oxidized to produce hydrogen ions (protons). The produced protons move in the electrolyte membrane toward the cathode (oxygen pole or air pole) together with water, while electrons reach the cathode via an external circuit. At the cathode, water is produced by reduction reaction of electrons and oxygen. At this time, the protons produced at the anode move with water molecules through the electrolyte membrane and, therefore, the electrolyte membrane is maintained in a wet state. The separator is exposed to a strong acid solution atmosphere at a temperature from room temperature to 100° C. because it is in contact with the porous supporting layer (carbon paper or the like) constituting the MEA.
The separator has the current collection function and the functions of separately supplying a fuel or an oxidizer and discharging a reaction product as well as the function of acting as a mechanical reinforcement at the time of stacking. The separator further has the function of releasing or uniformizing heat generated by power generation reaction.
Separator materials are roughly divided into carbon materials and metallic materials. As carbon materials, a piece of graphite obtained by machining a graphite block, a carbon resin molded piece, an expanded graphite molded piece, etc., exist. With such materials, there are problems described below. A graphite block is high-priced and a large number of cutting steps are required for cutting it. A carbon resin molded piece can crack easily. An expanded graphite molded piece has high gas permeability.
On the other hand, a metallic separator has high electric conductivity, thermal conductivity, mechanical strength and hydrogen gas impermeability. Further, the development mainly of a metallic separator using mainly austenitic stainless steel as a promising material on which machining for forming a channel for a raw material fluid can be easily performed and which therefore enables reducing the manufacturing cost and the thickness is being pursued. However, there is a problem that the metallic separator is low in corrosion resistance. That is, the electrolyte membrane is superacidic and the anode side is put in an oxidizing atmosphere at about 100° C. and the cathode side in a reducing atmosphere, as described above. Also, in the vicinity of the metallic separator, a reacting material and a reaction product contact and an uneven temperature distribution in the areal direction occurs. Therefore a local cell can form easily in the metallic separator and there is an extremely high risk of the metallic separator being corroded. Also, an acid produced by degradation/decomposition of the electrolyte membrane, for example, during use of the metallic separator in continuous operation for a long time further increases the possibility of corrosion. This acid not only corrodes and damages the metallic separator but also reduces the electric conductivity of the electrolyte membrane by eluted metal ions. Further, there is a problem that eluted metal ions are precipitated to reduce the performance of a precious metal catalyst such as platinum. It is, therefore, difficult to put the metallic separator into actual use.
As a means for solving these problems, a method of forming an electroconductive polymer coating on the surface of a metallic separator or a method of forming a corrosion-resisting metal coating layer such as gold or platinum plating is used. For example, patent document 1 discloses a metallic separator having a metallic base member on which a continuous channel is formed by pressing, and which is coated with a coating layer having high adhesion. According to this document, separation of the coating layer does not occur easily, and corrosion of the metallic base member can be prevented.
Patent document 2 discloses a metallic separator having an intermediate metal layer in which a flow channel can be easily formed by stamping, a corrosion-resisting metal layer provided on the outer surface of the intermediate metal layer, and a coating layer of an electroconductive agent and a resin binder formed on the surface of the corrosion-resisting metal layer. According to this document, the corrosion resistance of the metallic base member can be maintained.
Patent document 3 discloses, as an invention in an earlier application made public after the basic application for the right of priority of the present invention, a separator structure in which an electroconductive channeled plate and a metal plate are combined. Also, in patent document 3, the provision of a coating layer for preventing corrosion or for limiting the growth of a passive film over the entire surface of the metal plate or at least on the portion to be brought into contact with a meandering slot is proposed to prevent corrosion of the separator and reduce the contact resistance.
Patent document 1: Japanese Patent Application Laid-Open No. 2000-243408
Patent document 2: Japanese Patent Application Laid-Open No. 2003-272659
Patent document 3: Japanese Patent Application Laid-Open No. 2005-294155 | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates to a particle analysis method for analyzing particles on a sample which has a simple pattern surface.
Since speedy observation of an entire surface with particle analysis equipment is not impossible, after speedy observation of an entire surface is effected at first with particle detection equipment detecting diffusion light, etc., then based on the coordinate information of particles obtained by the particle detection equipment, an element analysis and a shape-observation of specific particles are usually accomplished in detail using particle analysis equipment.
If the error between the coordinate information of a particle in particle detection equipment and that corresponding to the above information in particle analysis equipment is greater than the view for the surveying of particles in particle analysis equipment, it is difficult to detect a particle by one trial of observation and the survey operator has to find particles by shifting the view consecutively and checking the image at each view.
This method not only places a burden on the survey operator because it is troublesome and time-consuming, but also leads to mistakes which very often causes some of the particles to be overlooked. Therefore adding an automatic survey function for this process to particle analysis equipment is required to remove these burdens and eliminate these mistakes. | {
"pile_set_name": "USPTO Backgrounds"
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The invention disclosed herein pertains to display devices such as are commonly known as neon signs. Such signs comprise glass tubes which are bent into various configurations and have electrodes sealed into their opposite ends. The color of the light which is emitted when a high electric potential is applied across the electrodes depends on the particular inert gas with which the tube is filled. Argon, Krypton and Neon are the most commonly used gases, but for the sake of brevity all such light emitting inert gas filled tubes will be called neon tubes herein.
Neon signs customarily comprise frames or panels on which the configured gas filled tube is supported by means of standoffs or insulating supports. Lead wires typically extend from the electrodes through the pinched-off ends of the glass tube and insulated wires which extend from a high voltage power supply are directly connected to the electrode wires and the connections are wrapped with insulating tape or a heat-shrinkable insulating tube. Fine gauge supply wire is used because the current through a neon tube is relatively small, in the milliampere range, but the power supplies have high output voltage. Voltages may range from about 6000 volts to 15,000 volts which, needless to say, produces trauma when voltages at that level are accidentally applied to the human body. The lead wires from the power supply to the neon tube are usually covered with a very flexible insulating material such as rubber having a wall thickness of about 1.5 mm. These signs are often positioned in rather hostile environments which can result in degradation of the wire insulation and unintended contact of the wire by persons.
As a result of the possible hazard of neon signs and the insulating systems that have been proposed for them, no safety organization such as Underwriters Laboratories, Inc. has ever, insofar as applicants are aware, allowed a neon sign design of any manufacturer to carry its certification mark. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
This invention relates to self-locking mounting bolt systems for mounting shelf boards to side walls of a type employed in furniture, as well as mounting bolts employed in such systems. More particularly, the invention relates to improved self-locking mounting bolt systems which provide for quick and simple assembly and disassembly in the field of various articles of furniture.
2. Description of Prior Art
In a typical mounting dowel system for use with furniture, a plurality of pins are utilized to mount shelf boards to side walls. As is well known in the art, the pins are driven into an end surface of each shelf board or side wall to fit into holes in an abutting side wall or shelf board, respectively, to prevent motion or slipping.
FIG. 1 is a fragumentary, exploded perspective view of an article of furniture such as a chest of drawers. It includes a pair of spaced, generally parallel side walls 10 (only one is shown), and a plurality of horizontal plates including a top plate 12 and two shelf boards 14. Each side wall 10 has two dowel pins 16 projecting from its end surface 18, the pins being generally cylindrical. The pins 16 have root portions received in holes formed in the upper end of the side wall 10. The depth of the holes is generally equal to about a half length of the pins 16. The top plate 12 has a pair of recesses 20 formed in the lower surface thereof, and their depth is also equal to about a half length of the pins 16. The pins 16 are adapted to fit into the complementary recesses 20 in the abutting top plate 12 after application of an adhesive material onto the end surface and the pins.
In a like manner, each shelf board 14 has four pins 24 projecting from an end surface 26 thereof. The pins 24 are adapted to be received in complementary recesses 28 formed in the abutting side wall 10.
Although not shown, it will be appreciated that another conventional method of connecting adjacent plate members together involves the use of studs and nuts. As is well known, a stud, which projects from an end surface of a plate member, is passed through a hole in an abutting plate member, followed by placing and tightening a nut on the stud to secure the abutting plate members.
In the mounting dowel systems, while plates can be successfully rigidized through dowels, it would be impossible to detach the plates in a non-destructive manner in order to disassemble the furniture for later transport and/or reassembly, because an adhesive material is usually applied to the dowels before attachment of the abutting plates.
In recent years there has been an increase in popularity of the concept of manufacturing furniture in a form that permits quick and simple assembly and disassembly in the field. This is partly because of the fact that there are still many multiple dwelling houses in Japan, such as apartments and condominiums, that do not have entrances, corridors, elevator cars, doors, etc. of sufficient widths and heights to allow assembled furniture to pass therethrough into individual rooms. Most of the manufacturers of this type of furniture ship their products to customers in disassembled form and reassemble the furniture in the field.
Additionally, in shipping their products, most manufacturers of furniture, whether of conventional type or of the above-described type, generally use truck services for transport to their customers. However, if the furniture is shipped in assembled form, its bulkiness requires a greater loading space as compared with its weight, resulting in extremely low transport efficiency. Also, a greater storage space is required if the furniture is stored in assembled form.
Accordingly, it is a principal object of this invention to provide improved self-locking mounting bolt systems for use in connecting various plates of a type employed in furniture assembly.
It is another object of this invention to provide improved self-locking mounting bolt systems for use in mounting shelf boards to side walls that provide for quick and simple assembly and disassembly of furniture in the field.
It is a further object of this invention to provide improved self-locking mounting bolt systems which provide for rigidized right angle interconnection of component plates of a type emplyed in furniture. | {
"pile_set_name": "USPTO Backgrounds"
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A network service provider may wish to have accurate knowledge of the locations of its customers. For example, a customer may interact with the service provider via a base station that customer's endpoint device is using to obtain a service. Since the wireless coverage in the vicinity of the customer depends on the proximity of the customer's endpoint device to the cell tower, a geo-fence may be defined for an area considered to be inside the coverage area of the cell tower. Unfortunately, using the coverage area associated with the cell tower to define a geo-fence does not produce accurate results. | {
"pile_set_name": "USPTO Backgrounds"
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Research on imaging apparatuses which irradiate light from a light source (e.g. laser) onto a subject, such as living body, and visualize the information inside the subject, has been energetically progressing in medical fields. An example of such a visualization technology using light is photoacoustic tomography (PAT). A photoacoustic tomography apparatus detects an acoustic wave (typically an ultrasonic wave) generated from a tissue of the living body, which absorbed energy of the light propagating in and diffusing from a subject, at a plurality of locations surrounding the subject. Then the obtained signals are mathematically analyzed, and the information related to the optical property inside the subject, particularly the absorption coefficient distribution, is visualized. Recently pre-clinical research on imaging the blood vessels of small animals using the photoacoustic tomography apparatus, and clinical research on applying the principle of the photoacoustic tomography apparatus to diagnose breast cancer or the like is energetically progressing.
In the case of photoacoustic tomography apparatus and ultrasonic diagnostic apparatus (apparatus for detecting acoustic waves reflected in living body and generating an image) which have been conventionally used in medical fields, images are usually generated using an average acoustic velocity of the subject (sound speed of acoustic wave inside the subject, propagation velocity of acoustic wave inside the subject or propagation speed of acoustic wave inside the subject). Generally sound speed is determined based on an experiential value or document-based values. However propagation speeds have individual differences, and sound speed also changes depending on the method of holding a subject, for example. Therefore if the sound speed used for generating an image and the actual sound speed are different, the resolution of an image drops considerably.
Patent Literature (PTL) 1, for example, discloses a way to solve this problem. According to the technology disclosed in Patent Literature (PTL) 1, sound speed is determined so that brightness or the contrast of each pixel (or voxel) is maximized. Thereby a drop in image quality, due to a mismatch of the sound speed used for generating the image and the actual sound speed, is suppressed.
However in the case of the technology in Patent Literature (PTL) 1, the brightness or contrast of the background noise also increases since the brightness or contrast of each pixel is maximized. Furthermore if noise is included in the detection signals, the sound speed is determined so that the total value of the noise component and normal signal component is maximized, therefore an accurate sound speed cannot be obtained, and the image blurs.
(PTL 1) Japanese Patent Application Laid-Open No. 2000-166925 | {
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The invention relates to an electroluminescent device comprising:
an electroluminescent element having an electroluminescent organic layer disposed between a
hole-injecting electrode and an electron-injecting electrode, and
a housing enclosing said electroluminescent element, said housing comprising
a first shaped part having a first sealing surface,
a box-like second shaped part having a second sealing surface with an -inner perimeter,
said electroluminescent element being mounted on said first shaped part,
said first and second shaped parts being connected to each other by means of a seal comprising
a closed ring of a sealing material extending between said first and second sealing surfaces.
The invention further relates to a method of manufacturing such an electroluminescent device.
An electroluminescent (EL) device is a device which, while making use of the phenomenon of electroluminescence, emits light when the device is suitably connected to a power supply. If the light emission originates from an organic material, said device is referred to as an organic electroluminescent device. An organic EL device may be used, inter alia, as a thin light source having a large luminous surface area, such as a backlight for a liquid crystal display or a watch. An organic EL device may also be used as a display if the EL device comprises a number of EL elements, which may or may not be independently addressable.
The use of organic layers as EL layers in an EL element is known. Known organic layers generally comprise a conjugated, luminescent compound. Said compound may be a low-molecular dye, such as a coumarin, or a high-molecular compound, such as a (poly)phenylenevinylene. The EL element also comprises two electrodes, which are in contact with the organic layer. By applying a suitable voltage, the negative electrode, i.e. the cathode, will inject electrons and the positive electrode, i.e. the anode, will inject holes. If the EL element is in the form of a stack of layers, at least one of the electrodes should be transparent to the light to be emitted. A known transparent electrode material for the anode is, for example, indium tin oxide (ITO). Known cathode materials are, inter alia, Al, Yb, Mg:Ag, Li:Al or Ca. Known anode materials are, in addition to ITO, for example, gold and platinum. If necessary, the EL element may comprise additional organic layers, for example, of an oxadiazole or a tertiary amine, which serve to improve the charge transport or the charge injection.
An EL device of the type mentioned in the opening paragraph is disclosed in PCT application WO 98/53644. In said known organic device, the sealing material is low-melting metal or a low-melting metal alloy. This metal material is used according to PCT application WO 98/53644. Experiments showed that the housing should be airtight and waterproof to such an extent that organic sealing materials cannot be employed as barrier materials in the housing. Even epoxy-based adhesives and high-molecular, halogenated or non-halogenated hydrocarbons, which are reputed to be the best barrier materials within the class of organic materials, are unsuitable. Furthermore, apart from the worse barrier properties, the large difference between the coefficients of expansion of organic sealing materials and, for example, glass, and the resulting bonding problems proved to be disadvantageous.
However, although in some applications the known device proves to be satisfactory, there are applications, especially for very small pitch EL devices, or devices for which the inherent electrical conductivity of the metal poses a problem, for which the use of metal sealing material is not satisfactory.
The invention aims to provide a device as described in the opening paragraph, which overcomes the problems of using metal sealing material.
To this end, the device is characterized in that the sealing material comprises an organic sealing material, and in the direction towards the interior of the second part, the sealing material maximally extends to the inner perimeter of the second sealing surface.
The inventors have realized that, although PCT application WO 98/53644 states that xe2x80x98organic materials cannot be used as barrier materialsxe2x80x99, organic materials can in fact be used as sealing materials, provided that specific conditions, as described above, are met.
Hitherto, when organic sealing materials were used, such materials were provided on one of the parts in a relatively thick layer, whereafter the two parts were pressed upon each other. The seal had a thickness of several tens of micrometers, and inherently some sealing material was pushed inside the housing. This gives rise to at least two problems.
Almost all organic materials comprise gases. They also permit diffusion, particularly of moisture through the material. The outgassing of said organic materials and the diffusion through the organic materials gives rise to the rapid degradation of the EL element as described in PCT application WO 98/53644.
In the device in accordance with the invention, the sealing material between the first and the second part comprises an organic sealing material, and in the direction towards the interior of the second part, the sealing material maximally extends to the inner perimeter of the second sealing surface. In said device, substantially no sealing material is present inside the housing. This strongly reduces the amount of gas that is released by the organic material due to outgassing.
In the device in accordance with the invention, the organic sealing material preferably has a thickness of is less than 100 micrometers at any position between the first and second sealing surfaces. Below this limit, capillary action can be used to deposit the sealing material between the sealing surfaces.
In the device in accordance with the invention, the organic sealing material preferably has a thickness of less than 10 micrometer, at any position between the first and second sealing surfaces, and a distance of at least 0.2 mm between the outer and inner perimeter of the seal throughout the ring. The strongly reduced thickness of the sealing material in combination with a width of at least 0.2 mm of the ring provides a strongly increased resistance to diffusion of moisture through the seal.
Further advantages are a reduced amount of material used. The reduced thickness of the seal also alleviates bonding problems and increases the strength of the seal.
Preferably, the organic sealing material is chosen from the group of epoxy-based adhesives and high-molecular, halogenated or non-halogenated hydrocarbons. The diffusion of moisture through such materials is relatively small.
Preferably, the organic sealing material comprises inorganic particles. Such particles may be, for example, Al2O3, SiO2 or Mg-silicate particles. The presence of such particles effectively increases the diffusion path length for moisture, because the moisture does not diffuse or diffuses much more slowly through inorganic materials. This increase of the diffusion path length decreases diffusion of moisture through the seal. The amount of organic sealing material (at an equal thickness of the seal) is also reduced, which reduces the amount of gas that may be released by the organic sealing material.
The method of the invention is characterized in that the connecting step comprises the steps of bringing the sealing surfaces of the first and the second part near or against each other; providing an organic sealing material around the outer perimeter of the contact area between the first and the second part and allowing the organic sealing material to be deposited between the sealing surfaces by capillary action. The method in accordance with the invention has the advantage that the transport of the sealing material is stopped as soon as the sealing material reaches the inner perimeter of the second sealing surface. Sealing material is therefore substantially absent in the inner part of the housing.
xe2x80x98Nearxe2x80x99 or xe2x80x98againstxe2x80x99 is understood to be direct contact, including a position at a distance conducive to capillary action, and comprising embodiments in which spacers are positioned in between the first and the second part,. When incorporated in the seal, said spacers may also decrease diffusion by increasing the effective diffusion path length.
Preferably, the sealing material is provided at a temperature at which no transport through capillary action takes place, which temperature is subsequently raised to such a value that transport of organic sealing material through capillary action takes place. The advantage of providing the sealing material at a cold xe2x80x98immobilexe2x80x99 temperaturexe2x80x99 and subsequently raising the temperature to a xe2x80x98capillary activexe2x80x99 temperature is that, prior to actual sealing, the provision of the sealing material can be checked.
As compared with the provision of sealing material in a layer on one or both sealing surfaces, much less material needs to be used. Due to inaccuracies and surface irregularities, an applied layer must usually have a larger thickness than the actual sealing layer to insure that sealing material touches both surfaces even at the positions where the gaps are largest. This means that a substantially larger sealing material layer (2xc3x97 micrometers) must be applied for an average seal thickness of x micrometer. Part or even a major part of the surplus sealing material will be pushed inside the housing. The method in accordance with the invention does not suffer from these problems, because substantially the entire sealing surface of the parts are provided with sealing material, without sealing material being pushed or otherwise finding its way inside the housing.
These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter. | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates generally to a dispenser of the pressure accumulating type, and is an improvement over my earlier U.S. Pat. No. 4,050,613. More particularly, the present pump includes a modified plunger/accumulator designed to avoid unwanted dribbles or drips after the discharge passage is thereby closed.
Dispensers and sprayers of the pressure accumulating type, disclosed in the aforementioned patent application and patent, have a plunger member which reciprocates on a hollow stationary piston in response to the force of return spring from below and hydraulic force from above. The plunger functions as a discharge valve which closes in response to spring pressure as it returns to its seated position against the underside of the plunger head, the discharge passage being formed in the plunger head and extending to the atmosphere from an accumulation chamber defined by a downwardly directed blind socket formed at the underside of the plunger head for snugly slidably receiving the plunger. Thus, upon depression of the plunger head, pressure within the primed pump chamber increases within the accumulation chamber to a degree sufficient to overcome the opposing force of the spring whereupon the plunger moves relative to the plunger head to thereby open the discharge. Dispensing of product will continue under pressure through the open discharge passage so long as the hydraulic pressure in the accumulation chamber continues to overcome the opposing force of the return spring. When the spring force takes over, i.e., upon insufficient finger pressure exerted on the plunger head or upon discharge of the pump chamber and accumulation chamber contents near the end of the plunger downstroke, the plunger automatically reseats within the plunger head socket to thereby close the discharge passage. As the pump chamber expands during the ensuing plunger upstroke, a new charge of product is drawn into the pump chamber through the valve controlled inlet contained within the hollow stationary piston.
Although the aforedescribed dispensing pump operates quite efficiently and effectively in discharging product after the discharge is closed, an optional approach is available for avoiding any unexpected discharge at the commencement of the recharge stroke of the plunger.
If the plunger head of the example the pump according to the aforementioned application or my earlier patent U.S. Pat. No. 4,050,613, is subjected to lateral or eccentric forces during the dispensing operation, as when the operator reciprocates the head non-axially, such forces tend to induce a frictional load between the plunger and discharge valve elements which can permit the plunger-discharge valve to be momentarily held open at the end of the plunger downstroke with a small quantity of product remaining within the discharge passage. When the actuating force on the head is relieved, even slightly, the frictional holding force or brake on the plunger is relaxed. This then causes the return spring to shift the plunger immediately to its discharge valve closing position. Thus, the small amount of product which had been left in the discharge passage at the end of the discharge stroke is now suddenly purged at the start of the plunger intake stroke as the plunger closes under the force of the spring. Thus, if the plunger member is partially or wholly unrestrained by frictional engagement due to opposing force couples or lateral pressure acting on the head, then it will respond continuously and promptly in the intended operating mode in balance between the hydraulic pressure and the opposing spring force.
Also, the dispensing pump of the aforementioned application carries a contoured surface interfacing the stationary piston as an integral part of the plunger head. Thus, when the upper end of the piston and the opposing matching inner end of the plunger head are brought in face-to-face contact during a depression of the head, before the dispensing operation, any air accumulated in the pump chamber is substantially purged by venting it through the discharge as that air is compressed to effect a shifting of the plunger relative to the head for opening the discharge. This contoured surface displaces air volume in the pump chamber and extends into the open upper end of the plunger so that such surface bottoms against the upper end of the stationary piston and ball check members at the end of the plunger head downstroke. Thus, it is possible to exercise the discharge stroke at a velocity producing a pumping rate in excess of the orifice discharge capacity at the controlled design pressure. In accordance with this dispensing pump arrangement, the plunger head reaches the bottom of its stroke while the plunger is still in the valve open mode, displaced from the seat in the head, and continuing the discharge at rated pressure, expelling the accumulated product as the spring force returns the plunger to its seated, valve closed position against the interior of the head. This may be called "after-spray" which could result in unwanted dribbles and drips from the discharge, similar to the inertial "after-spray" of throttling and non-pressure build-up pumps, but which is minimized by the aforedescribed pump arrangements and by the present pump development. | {
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The present invention relates to digital media distribution. In particular, this invention relates to the distribution of licenses to access digital media content distributed over a computer network.
Digital media content, as opposed to analog media, is susceptible to infinite reproduction while maintaining intact the quality of each replica. As such, digital media content is easily distributed over computer networks, which provide a medium for low-cost delivery of content to consumers with legitimate rights to access the content. Unfortunately, computer networks also provide a medium for piracy, unauthorized use, and illegal distribution of digital media content. A well-recognized example of a computer network is the Internet. The Internet has revolutionized the media industry by providing content owners the ability to distribute media to the consumer in an effective and expedient fashion. Additionally, Internet-based distribution of media content benefits consumers in that they have at their fingertips a wide selection of digital media content that is immediately available. Unfortunately, the advent of the Internet has also accelerated the illicit duplication of copyright-protected digital content. Faster computer processors, affordable storage capacity, widespread Internet usage and the advent of peer-to-peer file sharing networks have not only allowed consumers to acquire and play media files legitimately, but also to share them with unauthorized consumers.
A leading solution to this problem is Digital Rights Management (“DRM”) technology. In broad terms, DRM is a media distribution scheme that permits content owners to securely distribute media content to consumers through the use of digital licenses. DRM differs from traditional methods of encrypted media distribution in that DRM technology allows a content owner to keep control of the number of times content decryption may occur, the time period during which content decryption is available, the user's ability to make copies or to transfer the media object to another device, and other aspects of the use of the media. Traditional methods of encrypted media distribution deliver the media file and lose control of the content once the file is decrypted.
Application of a typical DRM system involves a subscriber, a content owner, a content distributor, and a license server. A subscriber is generally the media consumer who through a client computer requests, obtains, and plays media content. The internal programming of the media player (e.g. Microsoft® Windows Media Player) requires the subscriber to have a valid license to play the media content if the media content is coded with such a requirement. A content owner is an entity with rights over any form of intangible property such as digital media content. Examples of content owners include media companies, record labels, filmmakers, and recording artists. Content distributors are media retailers who most often distribute media content through their Internet website by content streaming or content downloading. In some cases, the content owner will distribute its own content in which case it simultaneously serves as a content distributor. Finally, a license server is the server that receives license requests from the subscriber's media player and downloads digital licenses to authorized consumers. A digital license contains the necessary decryption key as well as business model rules (such as the number of times the media file can be played and the expiration period of the license), which can be set by the content distributor.
The usual flow of events for media distribution employing a DRM system starts with a content owner who encrypts its media content with a key and packages it with information such as the content ID and the license acquisition universal resource locator (“LAURL”). The content ID is the identifier of the media file. The LAURL is the URL that points to the license server and allows the subscriber's computer to acquire a license if one is needed (i.e., is not already present on the computer system). Once the content owner packages the media content, it may transfer the media content to the content distributor. At this point the digital media is ready for distribution. Using preferred business models, the content distributor markets the media content to subscribers. A consumer who has subscribed to the content will then go to the content distributor website and download or stream the packaged media file. Depending on the architecture of the DRM system, a license to the media may also be delivered to the user's device at this time. The consumer's computer stores the license for future use and the media player then uses the license to decrypt and play the media content. Later attempts to play the media content by the user will cause the user's computer to use the license stored in the consumer's computer. Access will be provided to the media content, allowing it to be played, according to the business rules specified in the license. If the consumer transfers the media content to another consumer or to another device, on the first attempt to play the media content on such a new device, the media player will request a license from the server addressed by the LAURL packaged with the media content (such a request is generally called a challenge). Once the challenge has been successfully met, the license server will generate and download a license to the requesting computer. The consumer's computer stores the license for future use and the media player then uses the license to decrypt and play the media content. Later attempts to play the content by the user will cause the user's computer to use the license stored in the consumer's computer. Access will be provided to the media content, allowing it to be played, according to the business rules specified in the license.
Consumer access to obtain the media content in the first place or to obtain a license via a challenge requires some method of authentication. Consumers are generally required to enter a username and password before gaining access to the content distributor's lists of media content and/or before downloading media content, or before downloading a new license requested via a challenge. For example, after the consumer subscribes with the content distributor, every time she wants to obtain a song from the content distributor's website she enters a username and password and the encrypted media content is delivered to her along with the license. Alternatively, if the license is not delivered with the media content, the consumer's player will request a license and before the license is delivered to the media player, the subscriber will be prompted for username and password. If the consumer is an authorized subscriber the digital license is delivered, which enables the player to decrypt and play the media.
The username-and-password paradigm, however, falls short in protecting network-distributed media and at the same time is unduly cumbersome for the user. The username-and-password paradigm falls short in protecting network distributed media, because a user name and password are easily shared between individuals. Accordingly, a single user who shares her usermame and password with multiple users can easily enable those multiple users to obtain free copies of the media and the license to decrypt the media. In the extreme, a single user can easily post a username and password on a bulletin board or other electronic location, thereby enabling an unlimited number of other users to obtain playable copies of the media, thus undermining completely the content distributor's ability to generate profit from distribution of the content. At the same time, the username-and-password paradigm is unduly cumbersome because, by definition, it requires the user to identify herself in some manner, when such information is irrelevant to the content distributor, who typically does not need or want to know the identity of each recipient of a single copy of a mass distributed media. Instead, the content distributor wants to receive one royalty for each usable copy of the media distributed irrespective of who purchases the copy. In many cases, the username-and-password paradigm also requires the user to identify herself repeatedly, rather than once, and is therefore overly intrusive, deterring user acceptance. Alternatively, a “cookie”— a small file controlled by the browser but accessible by the server— containing the user name and other information can be stored on the user's computer. Many users, however, resist cookies because of the potential invasion of privacy that results.
Physical media distribution, such as concerts, provides a comparative analogy. In general a concert attendee does not have to identify herself with a password to gain admission. Instead, anyone with a valid ticket is admitted. If a person with a valid ticket wishes to leave and re-enter, however, a hand stamp is used to identify the attendee as she leaves. Subsequently, only that person will be allowed to re-enter the event, which she may do as many times as she wishes. If, on the other hand, the attendee exits and gives her ticket stub to a friend whose hand is not stamped, the friend cannot enter.
In network media distribution, however, because two or more users may use the same username and password (in some systems simultaneously), current state of the art DRM systems do not effectively prevent multiple persons from “entering” the same event using one “ticket.” Yet, as noted above, they are intrusive in that they require the user to identify herself with name and password, sometimes multiple times, or require storing cookies on her computer, in order to gain access.
User validation methods for protection of media content are well known in the art. As previously stated, user validation is typically achieved by a combination of a username and a password. Other methods of user validation include using digital tickets that are punched once the consumer receives the digital work, e.g., see U.S. Pat. No. 6,236,971 titled “System for controlling the distribution and use of digital works using digital tickets.” While these methods provide content owners with some protection of their media content, they either fail to control the usage of the media file once it has been delivered to the consumer or fail to control the number of users who receive the same media content.
What is needed, therefore, is a mechanism that can be used in network media distribution to “hand-stamp” consumers' computers so that once the media content has been paid for, only one consumer will be allowed to receive it and play it, including receiving it and playing it multiple times, while at the same time avoiding intrusive and annoying username and password queries or other unattractive alternatives. | {
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1. Field of the Invention
The present invention relates generally to the field of four-wheel drive power transmission systems for vehicles, particularly to such systems that transmit power to the first or two sets of wheels while the wheel sets have the same speed, and to the other set of wheels when the speed of the first wheel set exceeds that of the other wheel set.
2. Description of the Prior Art
Drive mechanisms have been devised that transmit power to only one set of wheels when the four wheels of the vehicle are rotating at nearly the same speed. However, when the driven wheels begin to overrun, the nondriven wheels are drivably connected to the transmission and become driven, whereas the driving wheels in this condition are no longer supplied with power. Sometimes this action is done by providing the nondriven set of wheels with an overrunning clutch and by gearing the clutch such that it becomes engaged when a predetermined speed differential between the driving and nondriven wheels occurs. This requires that the overunning clutch be manually locked in order to obtain four-wheel drive when the vehicle is driven in reverse or when engine braking is required. Other systems use a conventional differential to allow the front and rear axelshafts to deliver power while rotating at different speeds. These systems generally require a manual lock-up device to prevent excessive wheel spin when encountering surfaces on which the wheels may slip. It is desirable in the operation of a four-wheel drive vehicle that the driven wheels should be driveably disconnected from the transmission when the wheels are not driven in order to reduce drag on the engine and to avoid unnecessary wear.
In four-wheel drive systems, power is transmitted to a set of driven wheels and power is transmitted to another set of wheels only when the first set spins relative to the road surface. Usually it accomplishes this result by providing gearing between the driven and nondriven axleshafts that permits an element of a roller clutch in the driveline to overrun unless this slippage occurs. This overrun results because the gear set has a gear ratio that permits one element of the clutch to rotate at a preselected different speed than that of the nondriven wheels. When slippage of the driven wheels occurs, this speed differential is overcome and power is transmitted to the usually nondriven wheels. It is possible in systems of this type, after a forwardly driven vehicle is stopped and then driven in reverse, that the rear wheels will transmit power through the overrunning clutch and the gear set to the driven wheels. When this occurs, the speed of the driven wheels tends to exceed the speed of the usually nondriven wheels because of the effect of the gear ratio of the gear set that connects the axle. But because the wheels are of the same size and their linear speeds must be the same in straight ahead driving, the driven wheels are forced to scrub and slide across the road. | {
"pile_set_name": "USPTO Backgrounds"
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Machine-to-machine (M2M) applications are generally developed for various devices with sensors available in a network. M2M applications require access to individual devices and sensors for development of the M2M application. Sensors available in the network may be provided by different Original Equipment Manufacturers (OEMs), and hence may follow different standards or protocols for communication and coding. These sensors typically operate independently with little or no coordination among them. Further, the data captured by these sensors may not be in a standard format and data may be difficult to be analyzed. Therefore, the M2M application developers and OEMs face challenges in developing a new M2M application and OEM devices by using conventional application development platforms. | {
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The invention relates to a frequency modulator circuit arrangement comprising a phase modulator having a first input for a carrier signal, a second input for a modulation signal, and an output for the modulated carrier signal, and an integrator circuit having its output coupled to the input of the phase modulator.
Since frequency modulation is the time differential of phase modulation, a phase modulator circuit can be converted to a frequency modulator circuit by including an integrator circuit in the signal path to its modulation signal input. This fact is well-known; see, for example, the book "Information Transmission, Modulation and Noise" by M. Schwarz (McGraw Hill 1959) section 3-10, FIGS. 3-30. If a fixed frequency source (which may be crystal-stabilized) is connected to the carrier signal input of such a frequency modulator circuit, a variable-frequency signal generator circuit is obtained which can have advantages as far as stability is concerned as compared with a variable-frequency signal generator in the form of a crystal-controlled oscillator in which the frequency controlling property of the crystal is made variable by means of a varactor. However, frequency modulator circuits of the simple phase modulator plus integrator circuit kind are not very suitable for applications in which they would be required to handle quasi or actual d.c. modulation components, for example, in certain forms of signalling systems in which the modulation is in the form of a succession of stationary values. This unsuitability occurs because a d.c. modulation component implies a continuously increasing or decreasing output signal from the integrator circuit and a continuously increasing or decreasing phase shift produced by the phase modulator, and hence in an infinite dynamic range handling capability for the integrator circuit and phase modulator, unless the modulation is chosen so that the integral thereof with respect to time never exceeds (in either direction) values which can be handled by the integrator circuit and phase modulator. Choosing the modulation to satisfy this criterion in such a system tends to result in underutilization of the basic capabilities of the system. It is an object of the invention to mitigate this disadvantage. | {
"pile_set_name": "USPTO Backgrounds"
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Many prior art water chemistry test kits used for maintaining swimming pools, spas, fountains, water tanks, etc. consist of, among other things, a vial or vials, colored liquid reagents, and color comparison displays or charts. More recently and commonly used in the swimming pool industry and other industries are devices that are sometimes called ‘test blocks,’ in which two vials (typically one vial is used for testing chlorine levels and the other primarily for testing acid levels) are molded vertically together as one single unit, with corresponding colored comparison displays. Some examples of such test blocks are the Guardex 4-in-1 Test Kit (shown generally at http://swimmingpoolproducts.halogensupply.com/viewitems/pool-spa-test-kits-testing-supplies/guardex-4-in-1-pool-test-kits-reagents, although current displays of products on that website may not qualify as prior art with respect to the current inventions) and the Taylor Test Kits (shown generally at http://www.taylortechnologies.com/pool-spa.asp, although current displays of products on that website may not qualify as prior art with respect to the current inventions).
Prior art ‘test blocks’ have been used for several decades, but are the outgrowth of earlier swimming pool reagent test kits that originally were comprised of individual components, such as (a) glass test tube vials, (b) a holder to prevent spilling by keeping test tubes vertical, and (c) separate colored comparison displays. The test tubes typically were narrow vertical transparent cylinders or vials that were closed at the bottom and open at the top, and prior art test blocks include similar vertical test tube/vials of similar design, that have been combined with a base or other element that enable the vials/tubes to be conveniently positioned to be relatively vertical oriented and freestanding.
The relevant prior art test tubes generally have had smooth sides, a single opening that forms a mouth, with the mouth's opening being as wide or wider than the vial's body. The more recent prior art “test blocks” have replicated these “test tube” design features also, although some have vials with a generally rectangular or square cross-section formed by having generally flat elongated vertical sides instead of the rounded sides commonly found on glass test tubes. Additional features on some prior art test blocks are such things as fill lines, chemical names, and other indicia that are either molded into or printed onto the plastic vial(s) or block.
Colored comparison displays are commonly molded into the prior art block(s) adjacent to a corresponding vial (i.e. gradients of yellow plastic next to the chlorine test vial, etc.) and because the tests typically involve a visual evaluation of the color of the tested liquid, having the “color measuring scale” built into the container enables a user to easily compare the water being tested in the vial to the “standard” color display.
Vial caps likewise are commonly provided in prior art systems, to seal the liquids within the vials, and all components (test block, reagent liquids, caps, instructions, etc.) are usually packaged together as a “test kit” in a plastic, chemical resistant container.
Typically, in using a reagent test kit to test water in a swimming pool or other water feature, a user must take the following steps:
1. Submerge the test block several inches below the water's surface (18 inches is recommended to ensure that the sample is representative of the entire pool, rather than just the surface water which may have some local anomalies).
2. Turn the submerged test block so that the vials' openings are pointed upward (this allows air to escape and water to fill the vials).
3. Lift the test block with filled vials out of the water.
4. Adjust the water level in the vial to the fill line marker on the vial (this typically is done by just tipping the unit slightly and then shaking or tapping the test block to pour out enough of the water to drop the level to the desired test volume).
5. Put reagent (chemicals) into the water sample. This is typically done by squeezing a dropper containing colored liquid reagent until a designated number of reagent drops fall into the sample water in the indicated vial(s). For the test to be effective and meaningful, relative proportions of water sample and the reagent must be relatively precise. Prior art devices and systems accomplish this control of proportions by requiring the user to accurately control the volume of the water sample and the number of reagent drops put into that sample (as more thoroughly discussed below).
6. Shake or tap the test block repeatedly to mix the reagent and water thoroughly within the vertical vial (this is done until all the water in the vial has a chance to change color). The properties of the water being tested will determine the resulting color of the mixed reagent/water sample, thereby permitting the user to make the desired visual “measurement” described in the next step.
7. Make a visual comparison between the colored display and the test water in the vial.
Often vials have minor directives or comments or reminders (such as ‘Ideal” or “Add Acid”) to assist a user in determining a proper course of action after completing the water test.
Despite their usefulness, there are several problems associated with prior art test blocks. Some problems occur as a result of the vials being relatively narrow, elongated and vertical. For example, after being submerged, filled with water, and lifted from the pool, lowering the vial's water level to the fill line requires a user to shake, tap, or pour out excess water. This is generally not a very precise operation, and these efforts to get to the “correct” test water volume frequently results in too much water being removed from the vial. When this occurs, the “fill” steps of the process must be done again (otherwise the proportion of water to test chemicals will not be proper), starting with resubmerging the vial into the pool. There is no guarantee that the second attempt to properly fill the vial will be any more successful than the first, and it is not at all uncommon for three or four attempts to be needed in obtaining the correct amount of water in the vial. Such imprecise control and resulting unpredictability not only can be time consuming and inconvenient, but it is further frustrating when the user is in a hurry or must repeatedly dip his/her arm into a pool or other body of water that is exceptionally cold. Having two vials to fill (which is common in many test blocks) multiplies these problems/issues.
Another problem arises when colored reagent drops are added to the test water in the vial. Given the relatively small size of the droppers and vials and the conditions in which the testing is sometimes done (e.g., outdoors, in inclimate weather, etc.), it can be easy to miss or partially miss the narrow mouth of prior art vials or test blocks when dispensing the drops of testing chemicals from the dropper into the vial(s). Among other things, this can result in a user losing count of the number of drops added from the dropper to the vial and, consequently, having to do the test again from the beginning.
Furthermore, drops that successfully land in the vial do not always readily mix with the water in the vial. Even when being tapped or shaken, at least some of the prior art vials are so elongated and narrow that the shape seems to hinder or at least does not readily facilitate moving or stirring the water within them, so a user may need to take the additional step of placing a cap on the vial so that it can be shaken more vigorously (to accomplish the necessary mixing of the chemicals into the water being tested). Vial caps are typically available as part of such prior art systems, but being small and often loosely packaged in the test kit, the caps are easily lost or contaminated. One convenient alternative to such caps is to use one's finger or hand to cover the vial while shaking and mixing the chemical into the water, but that “finger” approach also risks contaminating the water sample or otherwise distorting the proportions of water/reagent, and can therefore result in an inaccurate test reading.
For at least these reasons, the narrow and elongated vertical vials of prior art test blocks have many inconveniences that slow down, interrupt, and even contaminate the water testing process. | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates to nasal packing made from sponge-like materials that are expansible from a dry state to form soft, resilient, absorbent bodies.
In U.S. Pat. No. 1,732,697, Ryan discloses a medicated, compressed sponge that is adapted for insertion into the nose, and that swells into contact with the irregular surface portions of the nasal cavity, when moistened. Similarly, Stevens U.S. Pat. No. 2,179,964, Kriwkowitsch U.S. Pat. No. 3,049,125, Gottschalk U.S. Pat. No. 3,570,494, Doyle U.S. Pat. Nos. 4,030,504, 4,646,739, and Des. 287,880, Rangaswamy U.S. Pat. No. 4,568,326, Brennan U.S. Pat. No. 4,950,280, and Sweden Patent No. 220,978 provide nasal hemostats and the like. Medical, catamenial, and like devices are disclosed in the following United States patents: Gearon U.S. Pat. No. 1,537,992, Munro U.S. Pat. No. 2,110,962, Robell U.S. Pat. No. 2,499,414, McLaughlin U.S. Pat. No. 2,739,593, Maro et al U.S. Pat. No. 3,084,689, Penska U.S. Pat. No. 3,306,294, Crockford U.S. Pat. No. 3,369,544, Burnhill U.S. Pat. No. 3,762,414, Davis et al U.S. Pat. No. 3,791,385, and Hirschman U.S. Pat. No. 4,175,561, and in Canada Patent No. 550,047 and France Patent No. 718,042.
Efficient hemostasis, such as after septal, sinus, or rhinoplastic surgery, or to abate nasal hemorrhage, requires the application of gentle pressure to ruptured major arteries and blood vessels over substantially all parts of the nasal cavity. It is not believed that the hemostatic devices provided heretofore function entirely adequately in those respects. | {
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The depletion of old growth forest has placed increasing demand within the forest industry for alternative wood products which make better use of old growth and stagnant growth timber and which also provide for greater use of second, third and later generation trees.
Several alternative wood products have emerged in an effort to address some of the needs in the industry. In this respect U.S. Pat. No. 4,394,409 discloses a composite wood product formed from four elongated triangular-shaped wood pieces. The four pieces are joined to form a composite wood product having a cross-sectional outline of a parallelogram and a hollow interior. An alternative embodiment is disclosed where each wood piece has a pair of machined keys to improve yield.
In U.S. Pat. No. 5,299,400 there is disclosed a composite wood product formed from four log parts, each log part having a three sided cross-section forming either right angled sectors and a third curved face or a right triangle. The log parts are assembled into a composite wood product so that their right angles form the corners of a rectangle with a hollow interior which is filled with concrete or other structural enhancing material, Similar examples of this alternative wood structure appear in U.S. Reissue 35,327 and French Patent No. 962589. Other attempts to offer improved composite wood products can be found in French Patent No. 2512729 and German Patent No. 964637.
While the composite wood products disclosed in the above mentioned references provide some improvements to the known art, there remains a continuing need for composite wood products providing additional resistance to shearing forces and impact forces, assembled from converted wood parts having a larger bonding surface and having a higher load bearing capacity without the preemptive need for the structural reinforcing material indicated in the prior art. Accordingly, it is an object of the invention to provide alternative converted wood articles for use in making composite wood products to fulfill the above needs in the art. | {
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This invention relates to the discovery and asexual propagation of a new and distinct variety of plum, Prunus salicina cv. ‘Suplumthirtynine’. The new variety was first hybridized by David Cain in 1998 and selected by Terry Bacon in 2002 as breeder number: ‘PL186YB’. The new variety was first evaluated by Terry Bacon near Wasco, Calif. in Kern County. The variety ‘Suplumthirtynine’ was originated by hybridization.
The new variety ‘Suplumthirtynine’ is characterized by ripening very late in the season. In the Wasco, Calif. area, the harvest season, September 10 through October 5, is about three weeks later than that of ‘Suplumsix’ (the subject of U.S. Plant Pat. No. 2,747), the variety it most closely resembles in appearance. The new variety ‘Suplumthirtynine’ is further characterized by relatively large-sized fruit for the season (average fruit diameter approximately 64 mm, compared to approximately 60 mm for ‘Suplumsix’) and amber-colored flesh.
The seed parent is an unpatented breeding selection, ‘91P-024’, and the pollen parent is an unpatented breeding selection, ‘92-P023’. The parent varieties were first crossed in March of 1998, with the date of planting of the progeny being January 1999, and the date of first flowering being March 2001. The new plum variety ‘Suplumthirtynine’ was first asexually propagated by Terry Bacon near Wasco, Kern County, Calif. in January 2003, by grafting.
The new variety ‘Suplumthirtynine’ is distinguished from its seed parent, ‘91P-024’, in that the new variety ripens about twelve weeks later than ‘91P-024’. The new variety ‘Suplumthirtynine’ also has amber-colored flesh compared to the reddish flesh of the seed parent.
The new variety ‘Suplumthirtynine’ is distinguished from its pollen parent, ‘92P-023’, in that the new variety ripens about ten weeks later than ‘92P-023’. The new variety ‘Suplumthirtynine’ also has amber-colored flesh compared to the reddish flesh of the pollen parent.
The new variety ‘Suplumthirtynine’ has been shown to maintain its distinguishing characteristics through successive asexual propagations by, for example, budding and grafting. | {
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There are two major types of absorption refrigeration equipment in commercial use: (1) air cooled systems using ammonia as the refrigerant and water as the absorbent, and (2) water cooled systems using water as the refrigerant and lithium bromide as the absorbent.
Although these are the major types in commercial use, and there are mamy patents relating to these and other types, variations have been patented from these general principles and the following are typical examples of such patents: U.S. Pat. Nos. 4,055,964--Swenson et al. and 2,350,115--Katzow.
Others have demonstrated air cooled absorption refrigeration systems using other absorbent, refrigerant pairs. The following patents relates to these systems: U.S. Pat. Nos. 4,433,554--Rojay et al. and 3,483,710--Bearint.
Still others have patented water cooled refrigeration systems using other salts or other salts in combination with lithium bromide as the absorbents. The following are examples of these: U.S. Pat. Nos. 3,609,086--Modahl et al. and 3,541,013--Macriss et al.
Water cooled refrigeration circuits using the double effect generator are also in commercial use and have been patented as seen in the following patents: U.S. Pat. Nos. 3,495,420--Loweth et al., 3,389,573--Papapanu et al., 4,183,228--Saito et al., and 2,182,453--Sellew.
In absorption refrigeration and/or heating systems, the generator, sometimes called desorber, is a very important part of the system and contributes significantly to the overall efficiency. Much attention has been given to the construction of these devices, and various arrangements are shown in the following patents: U.S. Pat. No. 3,323,323--Phillips, 3,608,331--Leonard, and 4,127,993--Phillips, and 4,424,688--Wilkinson.
These existing air cooled absorption refrigeration circuits have demonstrated cooling coefficients of performance as high as 0.50 using various absorbent/refrigerant pairs. These systems have also been demonstrated as heating only heat pumps with a coefficient of performance of up to 1.3.
As used herein, coefficient of performance; i.e. COP, is defined as the energy transferred at the load in BTU/unit of time over the energy provided to the system in BTU/unit of time, which is well understood by those skilled in the art.
Air cooled refrigeration circuits have also been demonstrated which can be reversed to provide either heating or cooling to an air conditioned space (a load) by switching the flow of an intermediate heat transfer solution typically consisting of water and antifreeze solutions such as ethylene glycol, etc.
Liquid cooled absorption refrigeration circuits using the double effect generator cycle to achieve high efficiency are commercially available. However, these systems are not suitable for use in heating a conditioned space (the heating load) since the refrigerant freezes at 32.degree. F. and therefore cannot be used in a space heating system at ambient temperatures below approximately 40.degree. F.
Absorption refrigeration and heat pump systems are well known in their basic operating characteristics and need little further description except to establish the definitions and context in which this invention will be later described.
In a typical system a refrigerant, water or other phase change material is dissolved in a absorbent (typically lithium bromide or other salts) and these are often called the "solution pair". The refrigerant is absorbed or desorbed (expelled) in or out of solution with the absorbent to varying degrees throughout the system and the heat of absorption is added or extracted to produce heating and cooling effects.
The solution pair enters a generator where it is subjected to heat and the applied heat desorbs (expells) the refrigerant water in the form of a vapor which is conveyed to the condenser. There, external ambient cooling condenses the refrigerant vapor to liquid, which is conveyed through an expansion valve, into an evaporator where heat is gained. In the refrigeration system operation the heat gained in the evaporator is from the cooling load.
The low pressure vapor then passes to an absorber where ambient cooling allows the absorbent solution to absorb the refrigerant vapor. The solution is then conveyed to a recuperator by a pump. The recuperator is a counterflow heat exchanger where heat from the absorbent/refrigerant solution, flowing from the generator to the absorber, heats the returning solution pair flowing from the absorber to the generator. In the heating cycle, the cooling applied at the absorber and/or the condenser is the heat delivery to the heating load.
As a matter of convenience and terminology herein, each part of the absorption system which operates at the same pressure is termed a chamber.
Conventional absorption refrigeration/heating systems are two chamber systems although three chamber systems appear in the prior art and have seen limited use. When operated as a heat pump two chamber systems give respectable heating performance but give poor cooling performance.
Using ammonia (NH.sub.3) as the refrigerant and water (H.sub.2 O) as the sorbent, heat pumping can occur from an ambient air source which is at temperatures below freezing. In a theoretical assessment where the air is treated as if it were dry so that no defrosting is necessary, the typical two chamber NH.sub.3 /H.sub.2 O heat pump would represent a significant improvement over what would be expected of a simple furnace. However, since heat pumps are more expensive than furnaces, cooling season performance benefits are needed to justify the added expense. In other words, the heat pump must act as an air conditioner also to offset the cost of a separate installation of an air conditioner with the furnace.
For cooling, an NH.sub.3 /H.sub.2 O system is predicted to have a COP equal to about 0.5. This low performance index causes unreasonable fuel (or energy) costs from excessive fuel (or energy) use. This low performance of the ammonia/water system results from the poor performance characteristics of the ammonia/water solution at the higher temperature ranges, if the heat is supplied to the absorption system at higher temperatures.
Three-chamber systems of various types have been suggested which would improve the performance by staging the desorption process into effects. This would allow for increasing the actual temperature at which the driving heat is added to the system (cycle). The reference Carnot cycle efficiency would be increased and the real cycle would follow suit. Until the present invention it was thought that this increase in temperature would represent an unreasonably high pressure, especially for ammonia/water systems, and would force the system to operate in regions for which data is not readily available.
In addition the pressure had tended to rule out ammonia/water in a three-chamber system. The search for organic materials such as halogenated hydrocarbons and other refrigerants as a replacement for the ammonia has been limited by fluid stability at these higher temperatures. Normal organic refrigerant stability tests have indicated that it is necessary for oil to be present for operation in vapor compression refrigerant systems. These high operating temperatures rule out most of the common refrigerants, particularly being heated directly by combustion products which often cause local hot spots, which result in working fluid degradation and/or corrosion of components.
U.S. Pat. No. 4,441,332--Wilkinson is an example of a four-chamber absorption refrigeration system to provide refrigeration and/or heat pump total capability. This prior art patent employs two chemically separated two-chamber systems which are mechanically integrated into a total system to take advantage of the high performance of one solution pair in a low temperature range for cooling and the advantages of the other solution pair in a high temperature range when the total system is heat pumping in the heating mode.
The invention described herein is an integrated three-chamber system having one solution pair using an organic material of unusual fluid stability at higher temperatures when manipulated in an apparatus and system to take advantage of its properties. The typical preferred solution pair for operation as part of the system and components of this invention is ammonia as the refrigerant and sodium thiocyanate as the absorbent.
Others have given consideration to this solution pair as examplified by the ASME publication "Performance of A Solar Refrigeration System Using Ammonia-Sodium Thiocyanate", by Swartmen et al., in November 1972 and the publication entitled "A Combined Solar Heating/Cooling System", by Swartmen and presented July 28-Aug. 1 1975 at the 1975 International Solar Energy Congress and Exposition and U.S. Pat. No. 3,458,445--Macriss et al.
The heat actuated, air cooled, double effect generator cycle absorption refrigeration system of this invention overcomes limitations of the existing prior art technology. The air cooled system of this invention eliminates the need for cooling water and the use of ammonia as the refrigerant avoids refrigerant freezing during heating operation. The double effect generator cycle permits high efficiency through internal heat recovery in the absorption refrigeration circuit. The use of sodium thiocyanate as the absorbent eliminates the need for analyzers and rectifiers to purify the refrigerant stream. Internal refrigerant flow reversal, to achieve heat/cool switching and defrosting, eliminates the need for intermediate water/antifreeze heat transfer loops to switch from heating to cooling operation. | {
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This invention relates to relatively high-power solid-state devices for operation in the gigahertz range and, more particularly, to high-power gallium arsenide (GaAs) Schottky barrier field-effect-transistor (FET) devices.
Considerable effort is currently underway directed at fabricating solid-state devices capable of providing 1 to 5 watts of saturated power in the 4 to 6 GHz range. Such devices are intended, for example, to replace traveling wave tubes and Morton triodes in high-frequency communication systems.
GaAs Schottky barrier units having multiple gates have been demonstrated to be capable of meeting the aforespecified power requirements in the indicated frequency range. Moreover, it was recognized that if such multiple-gate units could be fabricated in integrated form by a direct processing sequence based on electron lithography, units characterized by high reliability and low cost might be thereby realized. | {
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1. Field of the Invention
This invention relates to a hearing aid and, more particularly, to a hearing aid in which a reproducing transducer and a microphone are enclosed in one and the same housing.
2. Description of the Prior Art
In a conventional hearing aid wherein a reproducing transducer and a microphone are enclosed in one housing and are used at the same time, vibrations on the transducer side may be transmitted through the housing to the microphone side, thus resulting a resonance and deteriorated sound pickup sensitivity of the microphone. On the other hand, vibrations caused in the microphone due to its sound pickup operation may be transmitted through the housing to the reproducing transducer thus causing a resonance at the transducer and deteriorating its sound reproducing characteristics.
Moreover, when the transducer side vibrations are transmitted through the housing to the microphone side, the resulting resonance may be picked up by the microphone thus causing an acoustic feedback phenomenon known as howling.
Thus, in a certain prior art hearing aid, the transducer and the microphone are separated from each other by a partition wall mounted in the housing and are closely fitted in the housing by the medium of resilient rubber sheets for prohibiting transducer or microphone vibrations from being transmitted to the microphone or transducer through the housing and other connecting portions.
However, we have found that such separation of the transducer and the microphone by the partition wall and mounting them in the housing by the medium of rubber sheets or the like resilient means are not sufficient in general to prevent resonance from occurring between the transducer and the microphone and to prevent deterioration in their sound reproducing and sound pickup characteristics. Moreover, howling can not be prevented from occurring in such prior devices due to insufficient suppression of the resonance between the reproducing transducer and the microphone.
In another conventional hearing aid, the transducer and the microphone are mounted with a close fit between the housing wall and a support base plate by the medium of cushioning sheets made of rubber and similar resilient material and having plural peripheral projections, said base plate being provided in the housing and adapted for mounting of electrodes and other devices. Thus, vibrations produced at the transducer and microphone sides may be diffused or occasionally absorbed by these projections. However, since the vibrations per se may not be absorbed completely, such known device again is not sufficient to prevent the resonance between the transducer and the microphone and resulting howling, thus again giving rise to deterioration in the sound reproducing characteristics of the transducer and the sound pickup performance of the microphone. | {
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In some surgical procedures (e.g., colorectal, bariatric, thoracic, etc.), portions of a patient's digestive tract (e.g., the gastrointestinal tract and/or esophagus, etc.) may be cut and removed to eliminate undesirable tissue or for other reasons. Once the tissue is removed, the remaining portions of the digestive tract may be coupled together in an end-to-end anastomosis. The end-to-end anastomosis may provide a substantially unobstructed flow path from one portion of the digestive tract to the other portion of the digestive tract, without also providing any kind of leaking at the site of the anastomosis.
One example of an instrument that may be used to provide an end-to-end anastomosis is a circular stapler. Some such staplers are operable to clamp down on layers of tissue, cut through the clamped layers of tissue, and drive staples through the clamped layers of tissue to substantially seal the layers of tissue together near the severed ends of the tissue layers, thereby joining the two severed ends of the anatomical lumen together. The circular stapler may be configured to sever the tissue and seal the tissue substantially simultaneously. For instance, the circular stapler may sever excess tissue that is interior to an annular array of staples at an anastomosis, to provide a substantially smooth transition between the anatomical lumen sections that are joined at the anastomosis. Circular staplers may be used in open procedures or in endoscopic procedures. In some instances, a portion of the circular stapler is inserted through a patient's naturally occurring orifice.
Examples of circular staplers are described in U.S. Pat. No. 5,205,459, entitled “Surgical Anastomosis Stapling Instrument,” issued Apr. 27, 1993; U.S. Pat. No. 5,271,544, entitled “Surgical Anastomosis Stapling Instrument,” issued Dec. 21, 1993; U.S. Pat. No. 5,275,322, entitled “Surgical Anastomosis Stapling Instrument,” issued Jan. 4, 1994; U.S. Pat. No. 5,285,945, entitled “Surgical Anastomosis Stapling Instrument,” issued Feb. 15, 1994; U.S. Pat. No. 5,292,053, entitled “Surgical Anastomosis Stapling Instrument,” issued Mar. 8, 1994; U.S. Pat. No. 5,333,773, entitled “Surgical Anastomosis Stapling Instrument,” issued Aug. 2, 1994; U.S. Pat. No. 5,350,104, entitled “Surgical Anastomosis Stapling Instrument,” issued Sep. 27, 1994; and U.S. Pat. No. 5,533,661, entitled “Surgical Anastomosis Stapling Instrument,” issued Jul. 9, 1996; and U.S. Pat. No. 8,910,847, entitled “Low Cost Anvil Assembly for a Circular Stapler,” issued Dec. 16, 2014. The disclosure of each of the above-cited U.S. patents is incorporated by reference herein.
Some circular staplers may include a motorized actuation mechanism. Examples of circular staplers with motorized actuation mechanisms are described in U.S. Pub. No. 2015/0083772, entitled “Surgical Stapler with Rotary Cam Drive and Return,” published Mar. 26, 2015, now abandoned; U.S. Pub. No. 2015/0083773, entitled “Surgical Stapling Instrument with Drive Assembly Having Toggle Features,” published Mar. 26, 2015, issued as U.S. Pat. No. 9,936,949 on Apr. 10, 2018; U.S. Pub. No. 2015/0083774, entitled “Control Features for Motorized Surgical Stapling Instrument,” published Mar. 26, 2015, issued as U.S. Pat. No. 9,907,552 on Mar. 6, 2018; and U.S. Pub. No. 2015/0083775, entitled “Surgical Stapler with Rotary Cam Drive,” published Mar. 26, 2015, issued as U.S. Pat. No. 9,713,469 on Jul. 25, 2017. The disclosure of each of the above-cited U.S. Patent Publications is incorporated by reference herein.
While various kinds of surgical stapling instruments and associated components have been made and used, it is believed that no one prior to the inventor(s) has made or used the invention described in the appended claims.
The drawings are not intended to be limiting in any way, and it is contemplated that various embodiments of the technology may be carried out in a variety of other ways, including those not necessarily depicted in the drawings. The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present technology, and together with the description serve to explain the principles of the technology; it being understood, however, that this technology is not limited to the precise arrangements shown. | {
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The thin film magnetic recording disk in a conventional drive assembly typically consists of a substrate, an underlayer consisting of a thin film of chromium (Cr) or a Cr alloy, a cobalt-based ferromagnetic alloy deposited on the underlayer, and a protective overcoat over the magnetic layer. The word "magnetic" will be used to mean ferromagnetic, antiferromagnetic, ferrimagnetic or any other magnetic material suitable for magnetic recording. A variety of disk substrates such as NiP-coated AlMg, glass, glass ceramic, glassy carbon, etc., have been used. The microstructural parameters of the magnetic layer, i.e., crystallographic preferred orientation (PO), grain size, anisotropy and magnetic exchange decoupling between the grains, play key roles in the recording characteristics of the disk. The Cr underlayer is mainly used to control such microstructural parameters such as the PO, the unit cell size and grain size of the cobalt-based magnetic alloy.
One variation of the layer structure described above uses a very thin initial seed layer on the substrate to establish an appropriate nucleation base for the underlayer. Various materials have been used or proposed for seed layers, for example, Al, Cr, Ni.sub.3 P, Ta, C, W, FeAl and NiAl. Laughlin, et al., have described use of an NiAl seed layer followed by a Cr underlayer and a CoCrPt magnetic layer. The NiAl seed layer with the Cr underlayer was said to induce the [1010] texture in the magnetic layer. (See "The Control and Characterization of the Crystallographic Texture of Longitudinal Thin Film Recording Media", IEEE Trans. Magnetic. 32(5) September 1996, p. 3632).
The PO of the various materials forming the layers on the disk, as discussed herein, is not necessarily an exclusive orientation which may be found in the material, but is merely the most prominent orientation. When the Cr underlayer is sputter deposited at a sufficiently elevated temperature on a NiP-coated AlMg substrate a [200] PO is usually formed. This PO promotes the epitaxial growth of [1120] PO of the hexagonal close-packed (hcp) cobalt (Co) alloy, and thereby improves the magnetic performance of the disk. The [1120] PO refers to a film of --hexagonal structure whose (1120) planes are predominantly parallel to the surface of the film. (Likewise the [1010] PO refers to a film of hexagonal structure whose (1010) planes are predominantly parallel to the surface of the film).
In the prior art the optimal underlayer structure was believed to be one with as little deviation from the target PO as possible. For example, if [200] PO was the design goal for the underlayer, then it was thought that the more narrow the distribution of the orientation of the grains, the better and ideally every grain would be [200].
Alloys of chromium have been used for the underlayer. For example, CrTi and CrV have been used. The addition of limited amounts of titanium or vanadium modifies the lattice parameters by atomic substitution, but the crystalline nature of the underlayer is not modified. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The present invention relates to a recording/reproducing apparatus including a magnetic recording medium on which a data track pattern and a servo pattern are formed by patterns with recording regions and non-recording regions, a recording head, and a reproducing head. The invention also relates to a method of measuring a parameter that measures a predetermined parameter for at least one of a recording head and a reproducing head installed in a recording/reproducing apparatus.
2. Description of the Related Art
As one example of a recording/reproducing apparatus that can measure a predetermined parameter for at least one of a recording head and a reproducing head using this type of method of measuring a parameter, Japanese Laid-Open Patent Publication No. 2005-166115 discloses a hard disk drive apparatus (a “magnetic recording apparatus”) with an offset measuring function. This hard disk drive apparatus includes a discrete track-type hard disk (magnetic recording medium) where non-magnetic regions are formed between tracks in discrete regions (data track pattern regions), a composite magnetic head including a recording head and a reproducing head, a driving mechanism that moves the magnetic head between the inner periphery and the outer periphery of the hard disk, and a control unit that carries out overall control of the hard disk drive apparatus. The hard disk described above is provided with offset measurement regions that are used for carrying out an offset measuring process and are disposed between the discrete regions (data track pattern regions) for recording data and the servo regions (servo pattern regions) in which servo data is recorded. The offset measurement regions are entirely constructed of a magnetic material without non-magnetic regions being formed therein.
During an offset measuring process carried out by this hard disk drive apparatus, offset measurement signals (measurement patterns, hereinafter also referred to simply as “measurement signals”) are written in offset measurement regions on the hard disk in a state where data has not been recorded on the hard disk and the offset measurement regions have been initialized. More specifically, in a state where the reproducing head is being made on-track to an innermost track, for example, measurement signals are written in the offset measurement regions using the recording head. When doing so, in a hard disk drive apparatus of this type, when the magnetic head has been moved toward the inner periphery or the outer periphery of the hard disk, a line that joins the center in the width direction of the recording head and the center in the width direction of the reproducing head (as one example, a line that is parallel to the direction in which the arm extends) is intersected by the center line of a track (i.e., a skew angle is produced). Accordingly, when the reproducing head is being made on-track (i.e., when the center in the width direction of the reproducing head has been aligned with the center in the width direction of a track), the center in the width direction of the recording head will be positioned away from the center of the track, or in other words, the recording head will be made “off-track”. This means that the measurement signals will be recorded at positions that are separated from the center line of the track by a distance corresponding to the extent to which the recording head is made off-track.
Next, by reading the measurement signals using the reproducing head, the center in the radial direction of the regions in which the measurement signals were written, or in other words, a position that matches the center in the width direction of the recording head when the measurement signals were written is specified. More specifically, by moving the reproducing head in the radial direction of the hard disk by increments of a predetermined amount, the measurement signals are read from the offset measurement regions. Here, when the center in the width direction (i.e., the radial direction) of the reproducing head is positioned off the center in the radial direction of the regions where the measurement signals are written toward the inner periphery or the outer periphery, the amplitude of the reproducing signal for the read measurement signal decreases. On the other hand, when the center in the width direction (i.e., the radial direction) of the reproducing head matches the center in the radial direction of the regions where the measurement signals were written, the amplitude of the reproducing signal for the read measurement signal reaches its maximum value. Accordingly, the control unit specifies the center position of the reproducing head at a point where the amplitude of the reproducing signal for the measurement signals reaches its maximum value as the center in the radial direction of the regions in which the measurement signals were written and sets the distance between the specified center and the center of the reproducing head during the writing of the measurement signals (i.e., the center of the track) as the offset of the recording head with respect to the reproducing head, thereby completing the measurement process. | {
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This invention relates to a switch device and, more particularly, to a waterproof structure for a switch device.
2. Description of the Prior Art
Various types of switch devices are used depending upon a particular application. In certain applications, a switch device is frequently exposed to moisture, such as rain. One such application may be when the switch device is used in an automobile for controlling the position of an electrically powered seat. It would be desirable to enclose such a switch in a waterproof structure.
A variety of types of waterproof structures have been proposed for various types of switch devices. In a seesaw type switch, such as the type frequently used for controlling and lowering an electrically powered seat within an automobile, the prior art switches typically include a thin rubber sheet, through which a switch actuator for operating the switch is projected, for waterproofing the switch.
In the waterproof structure of the type described above, the rubber sheet is freely elastically deformed when the switch actuator is toggled. Thus, the rubber sheet prevents liquid from entering the upper surface of the switch housing into the interior of the switch. However, since the rubber sheet is made of a soft material, it is difficult to attach the sheet during manufacturing, and, as a result, certain fabrication steps must be performed manually. Additionally, since the elasticity of the rubber itself is limited, when a plurality of switches are mounted in the housing, sufficient waterproofing cannot be expected. Further, if liquid enters the switch housing through the rubber sheet, the liquid may cause an improper electrical contact of the switch. | {
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The present invention relates to a drive unit system including a flywheel which assists braking by storing energy during braking and from which energy is recovered at all other times. The drive unit system includes a drive engine, a gear shift transmission, and a flywheel accumulator. The flywheel accumulator helps accelerate a vehicle, as it is discharged, i.e. giving off rotational energy. Furthermore, the flywheel accumulator is used to brake the vehicle, whereby it is charged, i.e. takes up rotational energy. The braking energy is thus usefully recovered. Such drive units are intended, in particular, for city buses but are also suitable for short-haul rail vehicles. | {
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A Digital Micromirror Device™ (DMD™) is a type of microelectromechanical systems (MEMS) device. Invented in 1987 at Texas Instruments Incorporated, the DMD is a fast, reflective digital light switch. It can be combined with image processing, memory, a light source, and optics to form a digital light processing system capable of projecting large, bright, high-contrast color images.
The DMD is fabricated using CMOS-like processes over a CMOS memory. It has an array of individually addressable mirror elements, each having an aluminum mirror that can reflect light in one of two directions depending on the state of an underlying memory cell. With the memory cell in a first state, the mirror rotates to +10 degrees. With the memory cell in a second state, the mirror rotates to −10 degrees. By combining the DMD with a suitable light source and projection optics, the mirror reflects incident light either into or out of the pupil of the projection lens. Thus, the first state of the mirror appears bright and the second state of the mirror appears dark. Gray scale is achieved by binary pulsewidth modulation of the incident light. Color is achieved by using color filters, either stationary or rotating, in combination with one, two, or three DMD chips.
DMD's may have a variety of designs, and the most popular design in current use is a structure consisting of a mirror that is rigidly connected to an underlying yoke. The yoke in turn is connected by two thin, mechanically compliant torsion hinges to support posts that are attached to the underlying substrate. Electrostatic fields developed between the underlying memory cell and the yoke and mirror cause rotation in the positive or negative rotation direction.
The fabrication of the above-described DMD superstructure begins with a completed CMOS memory circuit. Through the use of six photomask layers, the superstructure is formed with alternating layers of aluminum for the address electrode, hinge, yoke, and mirror layers and hardened photoresist for sacrificial layers that form air gaps. | {
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The present invention is directed to compositions involved in cell cycle regulation and methods of use. More particularly, the present invention is directed to genes encoding proteins and proteins involved in cell cycle regulation. Methods of use include use in assays screening for modulators of the cell cycle and use as therapeutics.
Cells cycle through various stages of growth, starting with the M phase, where mitosis and cytoplasmic division (cytokinesis) occurs. The M phase is followed by the G1 phase, in which the cells resume a high rate of biosynthesis and growth. The S phase begins with DNA synthesis, and ends when the DNA content of the nucleus has doubled. The cell then enters G2 phase, which ends when mitosis starts, signaled by the appearance of condensed chromosomes. Terminally differentiated cells are arrested in the G0 phase, and no longer undergo cell division.
The hallmark of a malignant cell is uncontrolled proliferation. This phenotype is acquired through the accumulation of gene mutations, the majority of which promote passage through the cell cycle. Cancer cells ignore growth regulatory signals and remain committed to cell division. Classic oncogenes, such as ras, lead to inappropriate transition from G1 to S phase of the cell cycle, mimicking proliferative extra cellular signals. Cell cycle checkpoint controls ensure faithful replication and segregation of the genome. The loss of cell cycle checkpoint control results in genomic instability, greatly accelerating the accumulation of mutations which drive malignant transformation. Thus, modulating cell cycle checkpoint pathways and other such pathways with therapeutic agents could exploit the differences between normal and tumor cells, both improving the selectivity of radio and chemotherapy, and leading to novel cancer treatments. As another example, it would be useful to control entry into apoptosis.
On the other hand, it is also sometimes desirable to enhance proliferation of cells in a controlled manner. For example, proliferation of cells is useful in wound healing and where growth of tissue is desirable. Thus, identifying modulators which promote, enhance or deter the inhibition of proliferation is desirable.
Despite the desirability of identifying cell cycle components and modulators, there is a deficit in the field of such compounds. Accordingly, it would be advantageous to provide compositions and methods useful in screening for modulators of the cell cycle. It would also be advantageous to provide novel compositions which are involved in the cell cycle.
The present invention provides cell cycle proteins and nucleic acids which encode such proteins. Also provided are methods for screening for a bioactive agent capable of modulating the cell cycle. The method comprises combining a cell cycle protein and a candidate bioactive agent and a cell or a population of cells, and determining the effect on the cell in the presence and absence of the candidate agent. Therapeutics for regulating or modulating the cell cycle are also provided.
In one aspect, a recombinant nucleic acid encoding a cell cycle protein of the present invention comprises a nucleic acid that hybridizes under high stringency conditions to a sequence complementary to that of protein phosphatase type 5 (PP5). In a preferred embodiment, the cell cycle protein provided herein binds to rad9. In another preferred embodiment, PP5 dephosphorylates rad9.
In one embodiment, a recombinant nucleic acid is utilized which comprises a nucleic acid sequence encoding a peptide comprising a binding site for rad9. In another embodiment, a recombinant nucleic acid encoding a cell cycle protein is provided which comprises a nucleic acid sequence having at least 85% sequence identity to a PP5 protein and which binds rad9.
In another aspect of the invention, expression vectors are provided. The expression vectors comprise one or more of the recombinant nucleic acids provided herein operably linked to regulatory sequences recognized by a host cell transformed with the nucleic acid. Further provided herein are host cells comprising the vectors and recombinant nucleic acids provided herein. Moreover, provided herein are processes for producing a cell cycle protein comprising culturing a host cell as described herein under conditions suitable for expression of the cell cycle protein. In one embodiment, the process includes recovering the cell cycle protein.
In another aspect, the present invention provides isolated polypeptides which specifically bind to a cell cycle protein as described herein. Examples of such isolated polypeptides include antibodies. Such an antibody can be a monoclonal antibody. In one embodiment, such an antibody reduces or eliminates the biological function of said cell cycle protein.
Further provided herein are methods for screening for a bioactive agent capable of binding to a cell cycle protein. In one embodiment the method comprises combining a cell cycle protein and a candidate bioactive agent, and determining the binding of said candidate bioactive agent to said cell cycle protein.
In another aspect, provided herein is a method for screening for a bioactive agent capable of interfering with the binding of a cell cycle protein and a rad9 protein. In one embodiment, such a method comprises combining a cell cycle protein a candidate bioactive agent and a rad9 protein, and determining the binding of the cell cycle protein and the rad9 protein. If desired, the cell cycle protein and the rad9 protein can be combined first. In one embodiment, the agent which is identified is a small molecule.
Further provided herein are methods for screening for a bioactive agent capable of modulating the activity of cell cycle protein. In one embodiment the method comprises adding a candidate bioactive agent to a cell comprising a recombinant nucleic acid encoding a cell cycle protein, and determining the effect of the candidate bioactive agent on the cell. In a preferred embodiment, a library of candidate bioactive agents is added to a plurality of cells comprising a recombinant nucleic acid encoding a cell cycle protein.
Also provided herein is a method for screening for a bioactive agent capable of interfering with the dephosphorylation of rad9. In one aspect, the method comprises combining a cell cycle protein PP5 or fragment thereof having phosphatase activity, a candidate bioactive agent and rad9 or a phosphorylated fragment of rad9. The method further comprises determining the dephosphorylation activity of said cell cycle protein on said rad9.
In another aspect of the invention, a method is provided for screening for rad9 variants which modulate PP5 dephosphorylation of rad9. In one embodiment the method comprises combining a cell cycle protein PP5 or fragment thereof having phosphatase activity and a rad9 variant, and determining the dephosphorylation activity of said cell cycle protein on said rad9 variant.
In yet another aspect of the invention a method is provided for screening for PP5 variants which modulate PP5 dephosphorylation of rad9. In one embodiment the method comprises combining a cell cycle protein PP5 variant and rad9 or phosphorylated fragment of rad9, and determining the dephosphorylation activity of said cell cycle protein on said rad9 variant.
Also provided herein is a polypeptide consisting essentially of the carboxy terminal of PP5, wherein said polypeptide has phosphatase activity. Further provided herein is a variant of PP5, wherein said variant differs from a native PP5 polypeptide in that said variant has reduced phosphatase activity. In one embodiment, the reduced phosphatase activity is reduced dephosphorylation of rad9 or a phosphorylated fragment thereof. In a preferred embodiment the variant PP5 binds rad9 but does not have phosphatase activity, or has reduced phosphatase actiavity. In another embodiment, the variant is selected from the group consisting of the polypeptides wherein said native PP5 polypeptide has an H at position 244 and said variant has an A at said position 244, said native PP5 polypeptide has a D at position 274 and an R at position and said variant has an A at said positions 274 and 275, and said native PP5 polypeptide has an N at position 303 and said variant has an A at said position 303. It is understood that homologs of PP5 may-have different numbering of amino acids, and thus in one embodiment, amino acid(s) corresponding to corresponding positions which may not have the exact numbering of the homologs are substituted to form the variants described herein. Also provided herein are nucleic acids encoding the polypeptides and variants provided herein.
Other aspects of the invention will become apparent to the skilled artisan by the following description of the invention. | {
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The present invention relates to methods and systems for electronically or computationally transforming individual color components of an image generated by a color video display to correct chromatic aberration associated with an optical system used to view the display.
As used herein, the term "optical system" broadly includes any system in which one or more lens elements are used to form an image. It is well-known that the index of refraction of a lens element varies as a function of the wavelength of light, and that this causes the focal length of the lens element to be wavelength-dependent. This wavelength-dependent variation in focal length is known as the longitudinal chromatic aberration property of the lens element.
It is also well-known that the wavelength-dependent variation in the index of refraction causes a lens element to produce images of different sizes for different wavelengths of light. The difference between the image sizes or heights for different colors is referred to herein as lateral chromatic aberration.
Longitudinal and lateral chromatic aberrations in a lens element can create severe distortions of imagery, especially in the case of a wide angle lens element such as may be advantageously used in a head mounted display ("HMD"). An HMD is an apparatus which typically includes one or more video display devices mounted on a head frame or helmet that is worn by a person who views each display device through a virtual image optical system also mounted on the head frame or helmet. The virtual image optical system expands the field of view subtended by the display devices, thus magnifying the images they generate and providing the viewer with a more compelling feeling of immersion in the imagery. Various types of small, lightweight display devices have been used in HMD's, including monochrome cathode ray tubes ("CRT's"), monochrome and full color liquid crystal matrices, scanned LED arrays and fiber optic rope. Large field sequential full color CRT displays also may be incorporated into an HMD, as is disclosed in commonly assigned co-pending patent application Ser. No. 08/049,563, entitled "Head Mounted Display" and filed Apr. 19, 1993 in the name of Eric C. Haseltine, the disclosure of which is incorporated herein by reference.
Full color video or computer graphics images (e.g., images combining red, green and blue primary colors) generated by display devices having high resolution can provide a person wearing an HMD with a startling illusion of realism. However, chromatic aberration in the optical system through which the display devices are viewed may, along with other types of aberrations (e.g., spherical aberration, coma, astigmatism, field curvature, pin-cushion and barrel distortions), distort the imagery presented to the viewer to the point that the illusion of realism is substantially compromised.
The chromatic aberration properties of a lens element can be corrected. Conventional optical techniques for correcting chromatic aberration usually require the use of additional lens elements to provide achromatic doublet or apochromatic triplet lens combinations. These multi-element optical systems are larger, heavier and more expensive than a single simple positive lens. As a result, such conventional optical correction techniques are not well-suited for use in HMD's and other applications requiring a compact and lightweight optical system.
Various electronic and special image recording techniques which provide compensation for geometric optical distortions in display systems have been disclosed in the prior art, but these techniques have either failed to address the effect of chromatic aberration or do not provide chromatic aberration correction suitable for use with video imagery generated in real time, as would be required for an HMD driven by a computer graphic image generator in a virtual reality entertainment system.
In view of the foregoing, it would be desirable to be able to provide real time chromatic aberration correction for an optical system used to view a color video display, and it would be desirable to be able to provide such correction without requiring a multiple-element lens system or without otherwise adding to the size, weight and cost of the optical system. | {
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Automatic-tape-dispensing guns (xe2x80x9cATGxe2x80x9d) are well known. These guns are used to lay down a double-sided adhesive that is used to mount or bond two articles together. Such adhesive can have opposing sides of the same or varying tack and/or adhesion.
Currently, most of the ATG""s use rolls of tape that are 36 yards long. These rolls have a standard outer diameter of approximately 3.1875 inches when wound on a standard 1.375 inch outer diameter core. In a normal operation, one may use several of these rolls of tape in a given day. During each changeover, each roll of tape must be individually threaded in the ATG. This is a time consuming process that results in lost productivity.
Previous attempts to store greater lengths of tape on rolls of a standard outer diameter have failed in that thinner tape has a thin release-liner that easily breaks, or the adhesive layer is to thin to allow for an acceptable application.
Although ATG tape rolls of 60 yards in length exist such rolls have a standard outer diameter of approximately 4.3125 inches. Because the 60 yard rolls have an increased outer diameter, a specially sized gun such as the one manufactured by 3M(copyright) Corporation of Minneapolis, Minn., is required to use them. The purchase of this gun requires an extra investment on the part of the tape user.
There is a long felt need to develop an ATG tape that allows for a greater length of tape to be stored on rolls having a standard outer diameter. Therefore, a tape capable of being used in a standard size ATG that is able to be wound so as to provide for a greater length of tape per roll would be an important improvement in the art.
An object of the invention is to provide a double-sided tape for an automatic dispensing gun that overcomes some of the problems and shortcomings of the prior art.
Another object of the invention is to provide a double-sided tape for an automatic dispensing gun that is capable of being rolled so that nearly twice the length of tape is capable of being used in existing automatic tape dispensing gun.
Yet another object of the invention is to provide a double-sided adhesive transfer tape for an automatic dispensing gun.
Still another object of the invention is to provide a carrier supported double-sided tape for an automatic dispensing gun where the tape utilizes a liner having a thickness no greater than 2 mils. How these and other objects are accomplished will become apparent from the following descriptions and from the drawings.
The invention involves a roll of tape for an automatic tape gun. The tape is comprised of an adhesive layer having a liner-side surface and an exposed-side surface. A release-liner adheres to the liner-side surface of the adhesive layer. The invention involves the selection of the thickness of the adhesive-layer and the release-liner such that the ratio of tape length to roll diameter on a standard 1.375 inch outer diameter roll core where the tape roll has a standard outer diameter of approximately 3.1875 inches, is substantially greater than about 400:1, whereby tape of extended length is usable on standard tape guns thereby minimizing the number of tape-roll changeovers.
In one embodiment of the invention, the ratio of tape length to roll diameter is greater than about 500:1. In a preferred version of this embodiment, the ratio of tape length to roll diameter is greater than about 550:1.
The release liner used in the tape involved in the invention has a thickness no greater than 2 mils. While no specific material is required for the liner, in a preferred embodiment, the release liner is a polymeric film such as polypropylene, polyester, nylon or polystyrene. This preferred liner also has a thickness no greater than 2 mils. It is also noted that the tape is capable of being wound around the roll core in a conventional manner or it may be what is known as reverse wound (i.e., the release-liner faces the inner core).
In one embodiment of the invention, the adhesive layer may be what is known in the art as an unsupported adhesive layer while yet in another embodiment, the adhesive layer may be reinforced on one or both side surfaces. In a specific version of such embodiment, glass beads, or fibers of glass, pulp, paper and the like may be used to reinforce the adhesive.
While it is preferred that both of the adhesive surfaces are of the same tack and adhesion, those skilled in the art will recognize that it is possible to construct the tape with one surface having a stronger tack and/or adhesion than the other surface without departing from the spirit or scope of the invention.
In another embodiment of the invention, the adhesive layer includes a carrier having first and second sides with each side having adhesive thereon. The first-side adhesive forms the liner-side surface of the adhesive layer while the second-side adhesive forms the exposed-side surface.
The thickness of the carrier is less than about xc2xd mil. Although the carrier can be made of various materials including paper, tissue and the like, in a preferred embodiment of the invention, the carrier is made of a polymeric film.
In still another embodiment of the invention, the adhesive-layer thickness and the release-liner are selected such that the ratio of tape length to roll diameter on a standard 1.375 inch outer diameter roll core where the tape roll has a standard outer diameter of approximately 4.3125 inches, is substantially greater than 500:1. In a specific version of such embodiment, the ratio of tape length to roll diameter is greater than about 600:1 while in a more preferred version, the ratio is greater than about 800:1.
In yet another embodiment of the invention, the adhesive-layer thickness and the release-liner are selected such that the ratio of tape length to tape thickness for a one-inch length of tape is substantially greater than about 195:1. In a specific version of such embodiment, the tape length to tape thickness ratio is greater than about 270:1 while in a more specific version the length to thickness ratio is greater than about 370:1.
The invention also involves a method of manufacturing a roll of tape for use in an automatic-tape gun. Such method is comprised of the steps of: (1) preparing an adhesive layer having a liner-side surface and an exposed-side surface; (2) attaching a release-liner having a thickness of 2 mils or less to the liner-side surface of the adhesive; and (3) winding the film release-liner around a core. | {
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Recliner chairs are available that enable a person to assume a reclining position while reading a newspaper, watching the television or taking a nap. However, after the person has reclined in the chair for a period of time he may experience symptoms of lumbago, back pain, head discomfort or neck discomfort, due to the fact that many recliner chairs do not conform closely to contours of the human back vertebrae. Also, conventional recliner chairs are often not adjustable as regards the inclinaton angle of the back cushion; consequently the person may feel some discomfort after sitting in the chair for a long period of time.
The present invention concerns a device for supporting a person in a reclining position, so that the person's back vertebrae are adequately supported, whereby the person remains comfortable, even after extended periods of time. The device includes an adjustment for the inclination angle of the back cushion, whereby the person can set the device in a range of different inclination angles. | {
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For the past 40 years, the cellular cell has functioned as the atom of the wireless network, as shown in FIG. 1. A cellular system 100 includes a plurality of transmit points (TPs) 104 each with an associated coverage area or cell 102. UEs 106 communicate only with the TP 104 in the cell 102 in which the UE 106 is associated using an ID specific for the cell 102. When a UE 106 moves to another cell, a handover between TPs 104 must occur and the UE 106 is associated with a new TP 104 through a new cell ID. However, radio access performance is limited by inter-cell interference. Further, as shown in plot 200 of spectral efficiency in FIG. 2, there is non-uniform spectral efficiency across a cell. | {
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The invention relates generally to the field of merchandising displays for promotional articles or product. More particularly, the invention concerns a method of replenishing articles in a modular merchandising display and a modular merchandising display that can be easily replenished or refilled with product at the retailers thus eliminating the need for multiple packaging steps, cumbersome shipping and associated additional expense.
A variety of promotional displays exist for merchandising product, e.g., photographic film rolls, in a retail environment. Most common is the use of temporary merchandising displays often made from corrugated paperboard material, which comes to the retailer pre-stocked with product. These temporary merchandising displays are generally conveniently positioned on the retail floor and product contained therein is directly withdrawn by the consumer until all is depleted. Once the temporary merchandising display is empty of product, it is typically discarded and replaced with a new pre-filled temporary display unit.
Typical examples of prior art temporary merchandising displays are disclosed in U.S. Pat. Nos. 5,251,753 by Pigott et al, titled xe2x80x9cCombined Product Shipping And Display Unit,xe2x80x9d Oct. 12, 1993; U.S. Pat. No. 5,167,324 by Miller, titled xe2x80x9cShipping Carton And Display Unit For Tubes,xe2x80x9d Dec. 1, 1992; U.S. Pat. No. 3,308,934 by Reiner, titled xe2x80x9cDisplay Package,xe2x80x9d Mar. 14, 1967; U.S. Pat. No. 4,825,624 by Clacerano, titled xe2x80x9cModular Promotional Display,xe2x80x9d May 2, 1989; U.S. Pat. No. 5,293,99 by Neuman et al., titled xe2x80x9cCombined Shipping and Presentation Package,xe2x80x9d Mar. 15, 1994; U.S. Pat. No. 5,762,203 by Klawiter et al., titled xe2x80x9cContainer For Shipping And Displaying Of Product,xe2x80x9d Jun. 9, 1998; and U.S. Pat. No. 5,706,953 by Polvere, titled xe2x80x9cCombination Shipping Carton and Display Stand Formed With Insert Panels And Shelves. Each of these displays is adaptable to be used as a shipping carton for shipping merchandise and a display for displaying the merchandise. In some of the displays, such as the ones described in U.S. Patents ""991, ""324, and ""753, additional conversion elements or steps are required to convert the package into a suitable merchandising display.
It is well known in the packaging industry that temporary merchandising displays of the sort described above have generally complex designs and structures. Moreover, such merchandising displays are not usually assembled or filled automatically at the point of manufacture or packaging of the product.
The skilled artisan in the art of merchandising displays and product shipment is aware that it is a major shortcoming of the rather typical process that the pre-filled merchandising displays are generally bulky, heavy, costly, and difficult to stock and then ship.
Therefore, a need persists in the art for a modular merchandising display that is simple, convenient for the retailer to stock and display product, and cost effective to implement.
It is, therefore, an object of the invention to provide a replenishable merchandising display that can be efficiently replenished at the retail location.
Another object of the invention is to provide a replenishable merchandising display fabricated from structurally durable materials that enables considerably longer use.
To achieve these and other objects and advantages of the invention, a replenishable merchandising display comprises:
an upright standing, substantially rigid frame comprising a plurality of product compartments, each one of said plurality of product compartments having a top wall and an opposed bottom wall defining a base, and opposed side walls each being adjoined to a rear wall, and said opposed side walls exposing an opening to receive and access at least one generally polygonal-shaped modular receptacle; and
said at least one generally polygonal-shaped modular receptacle being removably stored in one of said plurality of product compartments, said at least one generally polygonal-shaped modular receptacle accommodating a predetermined quantity of sales unit of a product.
The present invention has the following advantages over prior art developments: cost effectiveness; increased product replenishing efficiency; reduced inventory for the retailer; elimination of multiple packaging steps and associated waste of packaging materials; and, elimination of the shipment of filled merchandising displays and the associated risk of loss. | {
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1. Field of the Invention
The present invention relates to a highly effective and also inert active penetrator, an active projectile, an active airborne body or an active multipurpose projectile with a constructively adjustable or settable relationship between penetrating power and lateral effect. The end ballistic total effect which is obtained from the penetrating depth and covering the surface or stressing of the surface is initiated in an active case by means of a releasable arrangement or installation which is independent of the position of the active body. This is achieved through the intermediary of a suitably inert transfer medium; for example, such as a liquid, a pasty medium, a plastic material, a material which is constituted of a combination of a plurality of components or a plastically deformable metal, within which, by means of pressure generating and/or detonative arrangement (also without any primary explosives) there is built-up with an integrated or functionally specified triggering initiation with integrated detonating safety a quasi-hydrostatic or, respectively, hydrodynamic pressure field, and which is transmitted to the surrounding, fragment forming or sub-projectile emitting casing.
For end ballistically active effective carriers, one usually distinguishes between:
Inertial projectiles (KE projectiles, spin or aerodynamically stabilized arrow or slender projectiles);
Hollow charges (HL projectiles, flat conical charges, preferably aerodynamically stabilized) with a triggering device;
Explosive projectiles with triggering device;
Inert fragmentation projectiles, for example, PELE (penetrator with increased lateral effects) or with disintegration charge possessing a triggering device;
So called multipurpose projectiles/hybrid projectiles (explosive and/or fragmentation effect with; for example, HL effect acting radially or in the direction of flight (ahead);
Tandem projectiles (KE, HL or combined);
Warheads (mostly with HL and/or fragmentation/explosive effect); and
Penetrators or sub-penetrators in airborne bodies or warheads.
Furthermore, for a series of the above-mentioned active body types there are available corresponding special constructions. These unfold as a rule, certain, constructively or technologically (material-type) specified effects. An effectively optimized configuration is however, mostly connected with a serious limitation in the effective range. In order to correspond with the requirements of a combat area, one mostly reaches back to a combination of a plurality of (two or three) separate effective carriers (for example separately supplied ammunition, mixed ammunition belts, and so forth). In a simplified manner, one combines; for example, inertial projectiles (KE effect) with explosive and fragmentation projectiles.
The simplification of the ammunition palette without any restriction in the effective spectrum is thus a constantly sought after path for a solution. In the area of inertial projectiles there is achieved a decisive advance by means of the laterally acting penetrators (PELE penetrators). Such types of PELE penetrators are disclosed; for example, in German Patent Publication DE 197 00 349 C1. This effective or active carrier combines the KE penetrating effect with a fragment or, respectively sub-projectile generation in such an advantageous manner that for an entire series of applications this ammunition concept in itself is sufficient to fulfill the set tasks. The decisive restriction in this functional principal consists of in that, for initiating the lateral effects, it is necessary to provide an interaction with the target, only then will there be built up a suitable internal pressure, through which the end ballistically active projectile casing can be laterally accelerated, or respectively disintegrated.
Through the present invention there is disclosed a way by means of which, with the least possible restrictions in the range of the effectiveness, there can be joined not only the power spectrum of purely inertial projectiles with those of explosive/fragmentation/multipurpose/tandem projectiles, but also the function of heretofore not combinable separate types of ammunition can be integrated therewith. Thereby, it becomes possible to combine the properties of the most different types of ammunition concepts in a single active carrier. This does not only lead to a significant improvement in the heretofore known multipurpose projectiles, but also to an almost unlimited broadening of the conceivable spectrum of utilization against ground, air and sea targets, and in the defense against airborne bodies.
The invention does not intend to utilize pyrotechnic powder or explosive materials alone as casing disintegrating or fragment accelerating elements. Such types of projectiles are known in the most different types of embodiments with and without triggering devices (referring; for example, to German DE 29 19 807 C2). Also German DE 197 00 349 C1 already mentions this capability; for example, in combination with an expansive medium as a individual component.
2. Discussion of the Prior Art
From the disclosure of U.S. Pat. No. 4,625,650 there is known an explosive incendiary projectile which is equipped with a hollow cylindrical as well as aerodynamically configured copper jacket, with a tubular penetrator consisting of heavy metal with an explosive charge. With consideration to the relatively small caliber (12.7 mm) a sufficient penetrating effect with additional lateral effect is alone not achievable due to physical reasons. Its active components in their functioning manner also do not provide the subject matter which is represented within the scope of this invention.
A further projectile is known from U.S. Pat. No. 4,970,960 which essentially encompasses a projectile core, as well as therewith associated and thus connected tip with a formed on mandrel, whereby the inner mandrel is arranged in a bore in the projectile core. It can be constituted of a pyrophoric material; for example, zirconium, titanium or their alloys. Also this projectile is not active; and as well does not contain any expansion medium.
From the disclosure of German Patent No. 32 40 310 there is known an armor rupturing projectile, by means of which there should be attained a conflagration effect in the interior of the target, whereby the projectile encompasses a cylindrical metal member which is extensively shaped as a solid body with a thereto attached tip, as well as an incendiary charge arranged within the hollow space of the metal member which charges; for example, is formed as a solid cylindrical body or as a hollow cylindrical casing. With regard to this projectile, the outer shape remains unchanged during penetration, in the interior there should be produced an adiabatic compression with an explosive-like combustion of the incendiary charge. Also in this instance, there are no active components present, and there are also no means for achieving a dynamic expansion of the metal body acting as a penetrator and its lateral disintegration or fragmentation.
In an extremely broader embodiment of all heretofore known solutions for the generation of lateral effects, there should be mostly provided basically as auxiliary means a sufficient internal pressure generating chemical and/or pyrotechnic aide, and not only minimized, but through its embedding in pressure transmitting media, under the lowest possible pyrotechnic demand or, respectively, volumetric use, there is achieved an optimum disintegration of these surrounding, fragment or sub-projectile producing or emitting casings or segments. Through this separation of the functions of pressure generation or pressure propagation or, respectively, pressure transfer there for the first time opens itself the heretofore in all arrangements known spectrum of application for individual active elements, projectiles or warheads. As examples, there should here serve expelled elements from large calibered ammunition externally or internally of a target, for expel airborne bombs for the attacking of shelters, for warheads up to TBM (tactical ballistic missile) defense, and for utilization in the so-called killer satellites, and finally in the utilization in super cavitating torpedoes (highest speed torpedoes).
From the disclosure of German Patent No. DE 197 00 349 C1 there are disclosed projectiles or warheads which, by means of an internal arrangement for the dynamic formation of expansion zones, produce subprojectiles or fragments with an intense lateral effect. Principally, this hereby relates to the interaction of two materials upon striking against armored targets, or during the penetration into or through homogeneous or structured targets in such a manner whereby the internal dynamically damaged material builds up a pressure field relative to material surrounding it, with a higher speed of an in or through penetrating material, and thereby imparts to the outer material a lateral velocity component. This pressure field is determined through the projectile, as well as through the target parameters: Since such types of penetrators, in their initial form as well as their individual components (fragments, subprojectiles) should possess a greatest possible end ballistic effect, for the casing there affords itself steel or preferably tungsten-heavy metal (WS). From the intended disintegration at specified target parameters there is then obtained a palette of suitable expansion media. In accordance with the selected combination, there are already produced impact speeds at less than 100 m/s expansion pressures which afford a dependable disintegration of the projectile or warhead. Technical or material specific auxiliary means or aids, such as for example, the configuring or, respectively, the partial weakening of the surface, or the selection of brittler materials as the casing material are basically not prerequisites; however, they expand the scope of configurations and the spectrum of use for these so-called PELE penetrators. | {
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1. Field of the Invention
The present invention relates to a surface machining method and apparatus. More particularly, the present invention relates to a surface machining method and apparatus for brittle materials such as semiconductor materials, ceramics, glass, or the like.
2. Description of the Related Art
Loose abrasive for lapping, polishing, etc. is mainly used in mirror grinding for brittle materials such as semiconductor materials and ceramics. The loose abrasive is suitable for obtaining a flat and smooth surface; however, it is not suitable for the grinding which requires large throughput and high shaping accuracy. Since many wafers are ground at the same time in order to obtain the large throughput, the apparatus must be large-sized. Moreover, since the diameter of the wafer has been increased, there is a disadvantage in the accuracy of the lapping plate when the wafer of a large diameter is machined. Furthermore, the wafer cannot be efficiently machined by the loose abrasive.
In order to eliminate the above-mentioned disadvantages, a loose abrasive processing apparatus (e.g. a lapping apparatus and a polishing apparatus) which performs a single wafer processing is desired. Moreover, the transfer from the loose abrasive processing to the bonded abrasive processing has been desired.
In the conventional bonded abrasive processing, the center of the workpiece is machined only by the abrasive grains on the radius of the grinding wheel, which goes through the rotational center of the workpiece. For this reason, there are disadvantages in that the width of the grinding wheel is small, and if the machining speed is raised, the grinding resistance acting on each abrasive grain becomes larger. Furthermore, there are disadvantages in that the accuracy greatly depends on the state of the grinding wheel (the form and the dressing state); thus, the bonded abrasive processing is not suitable for the mirror grinding.
Furthermore, since the abrasive grains move on the same track, the movement of abrasive grains cannot be greatly changed even if the conditions such as the number of rotations, etc. are changed. The abrasive grains are concentrated on the rotational center of the workpiece, and the abrasive grains in the other area do not go through the rotational center of the workpiece. Thereby, there is a disadvantage in that warps are scattered on the surface. | {
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In the gas turbine engine field, rotor stage assemblies are typically formed of a rotor disk and a plurality of rotor blades extending outwardly from the disk. The rotor stage assemblies are interdigitated between adjacent stator assemblies. An annular flow path for hot working medium gases extends through the rotor stage assemblies and the stator assemblies. Each stator assembly has airfoils which cooperate with the airfoils of the adjacent rotor blades to enable the rotor blades to efficiently remove energy from the hot working medium gases flowing through the assemblies. As a result of the intimate contact between the airfoils of the rotor blades and the hot working medium gases, heat is transferred from the hot gases to the rotor blades.
In modern aircraft engines, cooling air may be flowed through each blade to remove a portion of this heat from the blade, reducing the temperature level and spanwise gradients in the blades and thereby improving the service life of the blade. An example of such a coolable rotor blade is shown in U.S. Pat. No. 3,635,586 to Kent et al entitled "Method and Apparatus for Turbine Blade Cooling".
Heat transfer from the hot working medium gases to the rotor disk is also of concern. The hot working medium gases may locally heat the rim region of the disk causing thermal gradients and stresses which decrease the service life of the disk. One approach to solving this problem is to cool the face of the disk with jets of cooling air. An example of such a construction is shown in U.S. Pat. No. 2,858,101 to Alford. In Alford, cooling air is discharged in jets through a metering nozzle onto the face of the disk. The metering nozzles are oriented in a direction opposite to the direction of rotation of the disk.
Another approach is to flow purge air through a cavity between a rotor and stator structure, inwardly of the working medium flow path, to prevent the ingestion of hot gases from the working medium flow path. Work must be expended by the rotating machinery of the engine, such as a compressor, to pressurize the purge air. Accordingly, a loss of the purge air into the flow path decreases the efficiency of the engine.
The loss of purge air is increased by a large boundary layer between the purge air and the rotating rotor disk as compared with construction having a small boundary layer. The rotor disk acts as a centrifuge and through rotational forces pumps radially outwardly the air in the boundary layer. The flow outwardly of purge air may be balanced by the flow into the cavity of additional purge air, further decreasing the efficiency of the engine. Alternatively the purge air pumped from the boundary layer may be replaced by hot working medium gases from the flow path which are mixed with the purge air and recirculated to the gas path. Recirculating flow from the gas path into the boundary layer and back to the gas path causes deleterious heating of the rotor disk and also decreases the efficiency of the engine.
Accordingly, scientists and engineers continue to seek improved cooling systems for rotor assemblies which have minimal adverse effect upon the efficiency of the operating engines and yet provide satisfactory cooling of the rotor components. | {
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1. Field of the Invention
The present invention relates to a method of configuring a packet-switched wireless access network for simultaneous use of a micro-mobility tunnelling-type protocol and a Quality of Service (QoS) routing protocol, to a packet-switched wireless access network for performing the method, to a router for use in the method, to an access router for use in the method, to a mobile node for use in the method, and to a method of manufacturing such a mobile node
2. Description of the Related Art
Many different requirements are expected of the network layer in all-IP access networks (e.g. 4G cellular networks). Two in particular are mobility and QoS. The former enables users to communicate seamlessly with remote network nodes via the Internet wherever they are, whereas the latter enables users to receive different levels of service for certain types of traffic. However, research has shown that problems may arise when attempting to configure an access network to operate a mobility protocol at the same time as a QoS routing protocol.
Best effort routing protocols such as Open Shortest Path First (OSPF) have been extended with QoS functionality. For example QoS Extensions to OSPF (QoSPF) (see RFC 2676) have been proposed in which the routing architecture of OSPF is augmented to include QoS-related link metrics e.g. the amount of bandwidth available at each link. Since OSPF (and therefore QoSPF) is an intra-domain link state routing algorithm, each router in the access network stores a database of the entire topology of the domain. Each router discovers its neighbouring routers and sub-networks, and advertises its local environment to other routers in the administrative scope of the network using a reliable flooding mechanism. These advertisements are stored and updated to synchronise routing knowledge in the network. The routers in the network may operate on an explicit route basis or on a hop-by-hop basis.
When operating a QoS routing algorithm it is prudent to operate some resource reservation system. For example a Bandwidth Broker may be used to admit a Reservation Request for a packet flow to travel a certain path across the access network. The Bandwidth Broker stores a database of the network topology and link state (based on the router advertisements for example). Using the database the Bandwidth Broker can decide whether or not to accept the Reservation Request. Therefore for hop-by-hop routing, although in principle the QoS route might be changed by routers on the path as new link state information is gained, this is not practical since a new Reservation Request would need to be made to the Bandwidth Broker. Accordingly, once the route is chosen for the session the hop-by-hop route does not change until a handover is performed.
Mobility at the network layer is concerned with maintaining the routability of packet data to and from a mobile node when that mobile node moves away from its home access network The main candidate for provision of this functionality is Mobile IP (MIP), Very briefly MIP relies on a Home Agent in the home access network to tunnel IP packets to the domain where the mobile node is attached. The mobile node forms a Care-of Address (CoA) that is globally topologically correct in the network to which it is attached. The Home Agent encapsulates packets that it receives addressed to the mobile node's home address in another IP packet addressed to the CoA. In this way packet data may still reach the mobile node even when it is away from the home network. Further details of Mobile IP can be found in RFC 3344, 3775 and 3776 to which reference is specifically made.
However, when a mobile node hands over to a new access router, binding updates are triggered to the Home Agent, etc. These binding updates can introduce unwanted delays and loss of packets, and thereby degradation in performance from the user's perspective. When attached to a particular wireless access network (such as a cellular network), a mobile node may change its point of attachment (i.e. access router) quite frequently (e.g. every few minutes or more often, particularly if on the move). Each change triggers configuration of a new CoA, followed by the necessary binding updates. Doing this frequently (e.g. every few minutes) is not practical
Hierarchical Mobile IPv6 (HMIPv6) has been proposed (see RFC 4140) to address this problem. HMIPv6 provides a mobility agent known as a Mobility Anchor Point (MAP) in the access network. A MAP is a logical entity that handles micro-mobility for the mobile node. Micro-mobility is a change in point of attachment of the mobile node from one access router to another, both of which are within the same domain of the access network. Whenever this happens, the mobile node sends a binding update to the MAP (comprising a new Link local CoA or LCoA), but the mobile node's primary CoA (or Regional CoA or RCoA) remains unchanged In this way the mobile node can move between access routers in the same administrative domain without having to send a binding update to the Home Agent. In contrast when the mobile node changes point of attachment to an access router in a different access network, this is a macro-mobility event i.e. requiring a binding update to be sent to the Home Agent of the mobile node
When an access network operates both a mobility protocol (such as HMIPv6) and a QoS routing protocol, the requirement for all packets to pass through a particular MAP in the domain breaks one QoS route (gateway to access router and vice versa) into two. In particular, due to the high volume of traffic that it handles, it is almost certain that the MAP does not lie on the best QoS route from the gateway to the access router. Even though two QoS routes are then calculated (gateway to MAP, MAP to access router), their combination is by definition not the best QoS route if the MAP does not lie on the route that would be computed between the gateway and the access router. This causes a routing conflict between mobility on the one hand and QoS routing on the other. Thus attempts to operate both tunnelling-type mobility protocols and QoS routing protocols at the same time have not produced the performance gains that might be expected.
We have realised that this places a constraint on the scalability of the architecture In particular, as more and more mobile nodes bind to a particular MAP (e.g. if more access routers are added to the MAP's domain), it will have to handle not only the micro-mobility binding updates for the mobile nodes, but also the new QoS route computation and Reservation Requests as each mobile node moves between access routers It is believed that this network architecture is not scalable to handle both mobility and QoS for the numbers of mobile nodes present in today's cellular networks for example, nor those expected in future access networks,.
“Analysis of cross issues between QoS routing and i-mobility protocols”, Friderikos, V. et al., IEE Proc.-Commun., Vol. 151, No. 3, June 2004, discusses some of the issues raised above. This document suggests that to address the conflict between tunnel-based micro-mobility protocols (such as HMIPv6) and QoS routing protocols, the path between the MAP and the AR could be lengthened by placing the mobility agent closer to the network edge (e.g. gateway). In this way it is suggested that problems associated with the two QoS tunnels mentioned above can be reduced. However, the scalability problem is not mentioned. | {
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The present invention relates to a high frequency module, and particularly, to a high frequency module that employs a semiconductor chip for processing high frequency signals, such as a power amplifier module. | {
"pile_set_name": "USPTO Backgrounds"
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Field of the Invention
This invention relates generally to lighting assemblies for projecting a fill light, and more particularly to a system having a reflector and a fluorescent source wherein the source of the light is optimally placed with reference to both sides of the end plate of the housing, and in addition the tubes will act as a reflector due to the angular mounting position.
Fluorescent lighting in the Motion Picture or TV Studio and on location is a fairly new technology, as only recently have the fluorescent tubes come color corrected with phosphor coatings that permit blending of the fluorescent tube with incandescent halogen bulbs which have been widely used in the filed of Cinematography. It has been a conventional practice to position all fluorescent tubes in parallel to one another and a standard spacing between the socket end assemblies. This parallel tube positioning has always been a common practice in positioning the tubes within the housing. The placement of the tube in parallel is counterproductive, however, in that its light will be absorbed by the housing and spill light will be encountered which has to be corrected by a snoot for pinpoint lighting control to cut any unnecessary spill light. Further, the position of the tubes in parallel increases the dimensions and the weight of the fixture, which only permit smaller quantities of tubes to be spread in a large housing for complete accommodation of the tube size. The purpose of positioning the tube in a V at about a 110xc2x0 angle on both sides of the housing end panel permits up to doubling the amount of fluorescent tubes in a given housing, thus increasing the light output and decreasing the dimensions of the housing as well as the weight, and in this mounting position the tubes themselves act as a reflector. Furthermore, the complete elimination of the Snoot requirements that were needed to eliminate any spill light is also advantageous.
The present invention provides much improved illumination and light projection from a given lighting fixture design. Accordingly, it is a primary object of the invention to provide a lighting system which projects an increased amount of light from a given light source and toward a target, given the same power input, than has previously been achievable. Furthermore, another object of the invention to provide a housing that is compact, easy to handle and carry, lighter in weight, lesser in power consumption, higher in light output and simple to assemble and repair. The mounting position of the fluorescent tube angle permits an increase in the amount of tubes utilized in a giving housing, by positioning each tube on both sides of the end panel of the housing thus up to doubling the amount of tubes and reducing the size of the housing. between 33% to 50% from the standard size, in addition to utilizing the fluorescent tubes themselves as a reflector. | {
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(1) Field of the Invention
This invention relates to a scanning electron microscope or similar equipment, and more particularly to a scanning electron microscope or similar equipment capable of irradiating a plurality of beams of charged particles onto a specimen and displaying simultaneously the plurality of images of the specimen.
(2) Description of the Prior Art
There have heretofore been known a wide variety of scanning electron microscopes and similar equipment. For example, there is a scanning electron microscope as shown in FIG. 1, in which an electron beam emitted from an electron gun b in a microscope column a is imparted with a scanning movement by a deflection coil d, to which a scanning signal has already been fed from a scanning power supply c, whereby causing the electron beam to irradiate a specimen e while scanning same.
As the electron beams scans the specimen e, secondary electrons or the like are given off from the specimen e and detected by a detector f. Then, a resulting detection signal is amplified by an amplifier g and subsequently fed to a Braun tube (Cathode-ray tube) h, where an image of the specimen is displayed.
In FIG. 1, letters i and j indicate a condenser lens and objective lens respectively.
When observing an IC pattern formed on a silicon wafer by using such a scanning electron microscope, it is necessary in some instances to observe the specimen e at varied angles. In another instance, it may be desirous to observe the specimen e in this manner.
However, with a conventional scanning electron microscope as illustrated in FIG. 1, there are problems such that it takes some time for inclining the specimen e and, in addition, it is rather difficult to find out the same field of vision after the specimen e has been inclined. Such a conventional scanning electron microscope is also accompanied by another problem that it is incapable of obtaining at the same time a plurality of images of the specimen e seen at varied angles. | {
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The present invention relates to fuels for transportation which are derived from natural petroleum, particularly processes for the production of components for refinery blending of transportation fuels which are liquid at ambient conditions. More specifically, it relates to integrated processes which include selective oxidation of a petroleum distillate whereby the incorporation of oxygen into hydrocarbon compounds, sulfur-containing organic compounds, and/or nitrogen-containing organic compounds assists by oxidation removal of sulfur and/or nitrogen from components for refinery blending of transportation fuels which are friendly to the environment.
The oxidation feedstock is contacted with an immiscible phase comprising at least one organic peracid or precursors of organic peracid in a liquid phase reaction mixture. Maintaining the reaction mixture substantially free of catalytic active metals and/or active metal-containing compounds is an essential element of the invention. Blending components containing less sulfur and/or less nitrogen than the oxidation feedstock are recovered from the reaction mixture. Advantageously, at least a portion of the immiscible peracid-containing phase is also recovered from the reaction mixture and recycled to the oxidation. Integrated processes of this invention may also provide their own source of high-boiling oxidation feedstock derived from other refinery units, for example, by hydrotreating a petroleum distillate.
Beneficially, the instant oxidation process is very selective, i.e. preferentially compounds in which a sulfur atom the sterically hindered are oxidized rather than aromatic hydrocarbons. Products can be used directly as transportation fuels, blending components, and/or fractionated, as by further distillation, to provide, for example, more suitable components for blending into diesel fuels.
It is well known that internal combustion engines have revolutionized transportation following their invention during the last decades of the 19th century. While others, including Benz and Gottleib Wilhelm Daimler, invented and developed engines using electric ignition of fuel such as gasoline, Rudolf C. K. Diesel invented and built the engine named for him which employs compression for auto-ignition of the fuel in order to utilize low-cost organic fuels. Development of improved diesel engines for use in transportation has proceeded hand-in-hand with improvements in diesel fuel compositions. Modern high performance diesel engines demand ever more advanced specification of fuel compositions, but cost remains an important consideration.
At the present time most fuels for transportation are derived from natural petroleum. Indeed, petroleum as yet is the world""s main source of hydrocarbons used as fuel and petrochemical feedstock. While compositions of natural petroleum or crude oils are significantly varied, all crudes contain sulfur compounds and most contain nitrogen compounds which may also contain oxygen, but oxygen content of most crudes is low. Generally, sulfur concentration in crude is less than about 8 percent, with most crudes having sulfur concentrations in the range from about 0.5 to about 1.5 percent. Nitrogen concentration is usually less than 0.2 percent, but it may be as high as 1.6 percent.
Crude oil seldom is used in the form produced at the well, but is converted in oil refineries into a wide range of fuels and petrochemical feedstocks. Typically fuels for transportation are produced by processing and blending of distilled fractions from the crude to meet the particular end use specifications. Because most of the crudes available today in large quantity are high in sulfur, the distilled fractions must be desulfurized to yield products which meet performance specifications and/or environmental standards. Sulfur containing organic compounds in fuels continue to be a major source of environmental pollution. During combustion they are converted to sulfur oxides which, in turn, give rise to sulfur oxyacids and, also, contribute to particulate emissions.
Even in newer, high performance diesel engines combustion of conventional fuel produces smoke in the exhaust. Oxygenated compounds and compounds containing few or no carbon-to-carbon chemical bonds, such as methanol and dimethyl ether, are known to reduce smoke and engine exhaust emissions. However, most such compounds have high vapor pressure and/or are nearly insoluble in diesel fuel, and they have poor ignition quality, as indicated by their cetane numbers. Furthermore, other methods of improving diesel fuels by chemical hydrogenation to reduce their sulfur and aromatics contents, also causes a reduction in fuel lubricity. Diesel fuels of low lubricity may cause excessive wear of fuel injectors and other moving parts which come in contact with the fuel under high pressures.
Distilled fractions used for fuel or a blending component of fuel for use in compression ignition internal combustion engines (Diesel engines) are middle distillates that usually contain from about 1 to 3 percent by weight sulfur. In the past a typical specifications for Diesel fuel was a maximum of 0.5 percent by weight. By 1993 legislation in Europe and United States limited sulfur in Diesel fuel to 0.3 weight percent. By 1996 in Europe and United States, and 1997 in Japan, maximum sulfur in Diesel fuel was reduced to no more than 0.05 weight percent. This world-wide trend must be expected to continue to even lower levels for sulfur.
In one aspect, pending introduction of new emission regulations in California and Federal markets has prompted significant interest in catalytic exhaust treatment. Challenges of applying catalytic emission control for the diesel engine, particularly the heavy-duty diesel engine, are significantly different from the spark ignition internal combustion engine (gasoline engine) due to two factors. First, the conventional three way catalyst (TWC) catalyst is ineffective in removing NOx emissions from diesel engines, and second, the need for particulate control is significantly higher than with the gasoline engine.
Several exhaust treatment technologies are emerging for control of Diesel engine emissions, and in all sectors the level of sulfur in the fuel affects efficiency of the technology. Sulfur is a catalyst poison that reduces catalytic activity. Furthermore, in the context of catalytic control of Diesel emissions, high fuel sulfur also creates a secondary problem of particulate emission, due to catalytic oxidation of sulfur and reaction with water to form a sulfate mist. This mist is collected as a portion of particulate emissions.
Compression ignition engine emissions differ from those of spark ignition engines due to the different method employed to initiate combustion. Compression ignition requires combustion of fuel droplets in a very lean air/fuel mixture. The combustion process leaves tiny particles of carbon behind and leads to significantly higher particulate emissions than are present in gasoline engines. Due to the lean operation the CO and gaseous hydrocarbon emissions are significantly lower than the gasoline engine. However, significant quantities of unburned hydrocarbon are adsorbed on the carbon particulate. These hydrocarbons are referred to as SOF (soluble organic fraction). Thus, the root cause of health concerns over diesel emissions can be traced to the inhalation of these very small carbon particles containing toxic hydrocarbons deep into the lungs.
While an increase in combustion temperature can reduce particulate, this leads to an increase in NOx emission by the well-known Zeldovitch mechanism. Thus, it becomes necessary to trade off particulate and NOx emissions to meet emissions legislation.
Available evidence strongly suggests that ultra-low sulfur fuel is a significant technology enabler for catalytic treatment of diesel exhaust to control emissions. Fuel sulfur levels of below 15 ppm, likely, are required to achieve particulate levels below 0.01 g/bhp-hr. Such levels would be very compatible with catalyst combinations for exhaust treatment now emerging, which have shown capability to achieve NOx emissions around 0.5 g/bhp-hr. Furthermore, NOx trap systems are extremely sensitive to fuel sulfur and available evidence suggests that they would need sulfur levels below 10 ppm to remain active.
In the face of ever-tightening sulfur specifications in transportation fuels, sulfur removal from petroleum feedstocks and products will become increasingly important in years to come. While legislation on sulfur in diesel fuel in Europe, Japan and the U.S. has recently lowered the specification to 0.05 percent by weight (max.), indications are that future specifications may go far below the current 0.05 percent by weight level.
Conventional hydrodesulfurization (HDS) catalysts can be used to remove a major portion of the sulfur from petroleum distillates for the blending of refinery transportation fuels, but they are not efficent for removing sulfur from compounds where the sulfur atom is sterically hindered as in multi-ring aromatic sulfur compounds. This is especially true where the sulfur heteroatom is doubly hindered (e.g., 4,6-dimethyldibenzothiophene). Using conventional hydrodesulfurization catalysts at high temperatures would cause yield loss, faster catalyst coking, and product quality deterioration (e.g., color). Using high pressure requires a large capital outlay.
In order to meet stricter specifications in the future, such hindered sulfur compounds will also have to be removed from distillate feedstocks and products. There is a pressing need for economical removal of sulfur from distillates and other hydrocarbon products.
The art is replete with processes said to remove sulfur from distillate feedstocks and products. One known method involves the oxidation of petroleum fractions containing at least a major amount of material boiling above a very high-boiling hydrocarbon materials (petroleum fractrions containing at least a major amount of material boiling above about 550xc2x0 F.) followed by treating the effluent containing the oxidized compounds at elevated temperatures to form hydrogen sulfide (500xc2x0 F. to 1350xc2x0 F.) and/or hydroprocessing to reduce the sulfur content of the hydrocarbon material. See, for example, U.S. Pat. No. 3,847,798 in the name of Jin Sun Yoo and U.S. Pat. No. 5,288,390 in the name of Vincent A. Durante. Such methods have proven to be of only limited utility since only a rather low degree of desulfurization is achieved. In addition, substantial loss of valuable products may result due to cracking and/or coke formation during the practice of these methods. Therefore, it would be advantageous to develop a process which gives an increased degree of desulfuriztion while decreasing cracking or coke formation.
Several different oxygenation methods for improving fuels have been described in the past. For example, U.S. Pat. No. 2,521,698 describes a partial oxidation of hydrocarbon fuels as improving cetane number. This patent suggests that the fuel should have a relatively low aromatic ring content and a high paraffinic content. U.S. Pat. No. 2,912,313 states that an increase in cetane number is obtained by adding both a peroxide and a dihalo compound to middle distillate fuels. U.S. Pat. No. 2,472,152 describes a method for improving the cetane number of middle distillate fractions by the oxidation of saturated cyclic hydrocarbon or naphthenic hydrocarbons in such fractions to form naphthenic peroxides. This patent suggests that the oxidation may be accelerated in the presence of an oil-soluble metal salt as an initiator, but is preferably carried out in the presence of an inorganic base. However, the naphthenic peroxides formed are deleterious gum initiators. Consequently, gum inhibitors such as phenols, cresols and cresyic acids must be added to the oxidized material to reduce or prevent gum formation. These latter compounds are toxic and carcinogenic.
U.S. Pat. No. 4,494,961 in the name of Chaya Venkat and Dennnis E. Walsh relates to improving the cetane number of raw, untreated, highly aromatic, middle distillate fractions having a low hydrogen content by contacting the fraction at a temperature of from 50xc2x0 C. to 350xc2x0 C. and under mild oxidizing conditions in the presence of a catalyst which is either (i) an alkaline earth metal permanganate, (ii) an oxide of a metal of Groups IB, IIB, IIIB, IVB, VB, VIB, VIIB or VIIIB of the periodic table, or a mixture of (i) and (ii). European Patent Application 0 252 606 A2 also relates to improving the cetane rating of a middle distillate fuel fraction which may be hydro-refined by contacting the fraction with oxygen or oxidant, in the presence of catalytic metals such as tin, antimony, lead, bismuth and transition metals of Groups IB, IIB, VB, VIB, VIIB and VIIIB of the periodic table, preferably as an oil-soluble metal salt. The application states that the catalyst selectively oxidizes benzylic carbon atoms in the fuel to ketones.
Recently, U.S. Pat. No. 4,723,963 in the name of William F. Taylor suggests that cetane number is improved by including at least 3 weight percent oxygenated aromatic compounds in middle distillate hydrocarbon fuel boiling in the range of 160xc2x0 C. to 400xc2x0 C. This patent states that the oxygenated alkylaromatics and/or oxygenated hydroaromatics are preferably oxygenated at the benzylic carbon proton.
More recently, oxidative desulfurization of middle distillates by reaction with aqueous hydrogen peroxide catalyzed by phosphotungstic acid and tri-n-octylmethylammonium chloride as phase transfer reagent followed by silica adsorption of oxidized sulfur compounds has been described by Collins et al. (Journal of Molecular Catalysis (A): Chemical 117 (1997) 397-403). Collins et al. described the oxidative desulfurization of a winter grade diesel oil which had not undergone hydrotreating. While Collins et al. suggest that the sulfur species resistant to hydrodesulfurization should be susceptible to oxidative desulfurization, the concentrations of such resistant sulfur components in hydrodesulfurized diesel may already be relatively low compared with the diesel oils treated by Collins et al.
U.S. Pat. No. 5,814,109 in the name of Bruce R. Cook, Paul J. Berlowitz and Robert J. Wittenbrink relates to producing Diesel fuel additive, especially via a Fischer-Tropsch hydrocarbon synthesis process, preferably a non-shifting process. In producing the additive, an essentially sulfur free product of these Fischer-Tropsch processes is separated into a high-boiling fraction and a low-boiling fraction, e.g., a fraction boiling below 700xc2x0 F. The high-boiling of the Fischer-Tropsch reaction product is hydroisomerizied at conditions said to be sufficient to convert the high-boiling fraction to a mixture of paraffins and isoparaffins boiling below 700xc2x0 F. This mixture is blended with the low-boiling of the Fischer-Tropsch reaction product to recover the diesel additive said to be useful for improving the cetane number or lubricity, or both the cetane number and lubricity, of a mid-distillate, Diesel fuel.
U.S. Pat. No. 6,087,544 in the name of Robert J. Wittenbrink, Darryl P. Klein, Michele S Touvelle, Michel Daage and Paul J. Berlowitz relates to processing a distillate feedstream to produce distillate fuels having a level of sulfur below the distillate feedstream. Such fuels are produced by fractionating a distillate feedstream into a light fraction, which contains only from about 50 to 100 ppm of sulfur, and a heavy fraction. The light fraction is hydrotreated to remove substantially all of the sulfur therein. The desulfurized light fraction, is then blended with one half of the heavy fraction to product a low sulfur distillate fuel, for example 85 percent by weight of desulfurized light fraction and 15 percent by weight of untreated heavy fraction reduced the level of sulfur from 663 ppm to 310 ppm. However, to obtain this low sulfur level only about 85 percent of the distillate feedstream is recovered as a low sulfur distillate fuel product.
There is, therefore, a present need for catalytic processes to prepare oxygenated aromatic compounds in middle distillate hydrocarbon fuel, particularly processes, which do not have the above disadvantages. An improved process should be carried out advantageously in the liquid phase using a suitable oxygenation-promoting catalyst system, preferably an oxygenation catalyst capable of enhancing the incorporation of oxygen into a mixture of organic compounds and/or assisting by oxidation removal of sulfur or nitrogen from a mixture of organic compounds suitable as blending components for refinery transportation fuels liquid at ambient conditions.
This invention is directed to overcoming the problems set forth above in order to provide components for refinery blending of transportation fuels friendly to the environment.
Economical processes are disclosed for production of components for refinery blending of transportation fuels by selective oxidation of a petroleum distillate whereby the incorporation of oxygen into hydrocarbon compounds, sulfur-containing organic compounds, and/or nitrogen-containing organic compounds assists by oxidation removal of sulfur and/or nitrogen from components for refinery blending of transportation fuels which are friendly to the environment. This invention contemplates the treatment of various type hydrocarbon materials, especially hydrocarbon oils of petroleum origin which contain sulfur. In general, the sulfur contents of the oils are in excess of 1 percent.
For the purpose of the present invention, the term xe2x80x9coxidationxe2x80x9d is defined as any means by which one or more sulfur-containing organic compound and/or nitrogen-containing organic compound is oxidized, e.g., the sulfur atom of a sulfur-containing organic molecule is oxidized to a sulfoxide and/or sulfone.
In one aspect, this invention provides a process for the production of refinery transportation fuel or blending components for refinery transportation fuel, which includes: providing oxidation feedstock comprising a mixture of hydrocarbons, sulfur-containing and nitrogen-containing organic compounds, the mixture having a gravity ranging from about 10xc2x0 API to about 100xc2x0 API; contacting the oxidation feedstock with an immiscible phase comprising at least one organic peracid or precursors of organic peracid in a liquid phase reaction mixture maintained substantially free of catalytic active metals and/or active metal-containing compounds and under conditions suitable for the oxidation of one or more of the sulfur-containing and/or nitrogen-containing organic compounds; separating at least a portion of the immiscible peracid-containing phase from the reaction mixture; and recovering a product comprising a mixture of organic compounds containing less sulfur and/or less nitrogen than the oxidation feedstock from the reaction mixture. Conditions of oxidation include temperatures in a range upward from about 25xc2x0 C. to about 250xc2x0 C. and sufficient pressure to maintain the reaction mixture substantially in a liquid phase.
In a further aspect of this invention, at least a portion of the immiscible peracid-containing phase separated from the oxygenated phase of the reaction mixture is recycled to the reaction mixture.
This invention is particularly useful towards sulfur-containing organic compounds in the oxidation feedstock which includes compounds in which the sulfur atom is sterically hindered, as for example in multi-ring aromatic sulfur compounds. Typically, the sulfur-containing organic compounds include at least sulfides, heteroaromatic sulfides, and/or compounds selected from the group consisting of substituted benzothiophenes and dibenzothiophenes.
Generally, for use in this invention, the immiscible phase is formed by admixing a source of hydrogen peroxide and/or alkylhydroperoxide, a source of an aliphatic monocarboxylic acid containing 1 to about 8 carbon atoms per molecule, and water. The ratio of acid to peroxide is generally in a range upward from about 1, preferably in a range from about 1 to about 10.
Advantageously, the immiscible peracid-containing phase is an aqueous liquid formed by admixing, water, a source of acetic acid, and a source of hydrogen peroxide in amounts which provide at least one mole acetic acid for each mole of hydrogen peroxide. Preferably the ratio of acetic acid to hydrogen peroxide is in a range from about 1 to about 10, more preferably in a range from about 1.5 to about 5. Conditions of oxidation include temperatures in a range upward from about 25xc2x0 C. to about 250xc2x0 C. and sufficient pressure to maintain the reaction mixture substantially in a liquid phase.
In one aspect of this invention all or at least a portion of the oxidation feedstock is a product of a hydrotreating process for petroleum distillate consisting essentially of material boiling between about 50xc2x0 C. and about 425xc2x0 C. which hydrotreating process includes reacting the petroleum distillate with a source of hydrogen at hydrogenation conditions in the presence of a hydrogenation catalyst to assist by hydrogenation removal of sulfur and/or nitrogen from the hydrotreated petroleum distillate. Generally, useful hydrogenation catalysts comprise at least one active metal, selected from the group consisting of the d-transition elements in the Periodic Table, each incorporated onto an inert support in an amount of from about 0.1 percent to about 30 percent by weight of the total catalyst. Suitable active metals include the d-transition elements in the Periodic Table elements having atomic number in from 21 to 30, 39 to 48, and 72 to 78.
Hydrogenation catalysts beneficially contain a combination of metals. Preferred are hydrogenation catalysts containing at least two metals selected from the group consisting of cobalt, nickel, molybdenum and tungsten. More preferably, co-metals are cobalt and molybdenum or nickel and molybdenum. Advantageously, the hydrogenation catalyst comprises at least two active metals, each incorporated onto a metal oxide support, such as alumina in an amount of from about 0.1 percent to about 20 percent by weight of the total catalyst.
In one aspect, this invention provides for the production of refinery transportation fuel or blending components for refinery transportation fuel comprising the following steps: hydrotreating a petroleum distillate consisting essentially of material boiling between about 200xc2x0 C. and about 425xc2x0 C. by a process which includes reacting the petroleum distillate with a source of hydrogen at hydrogenation conditions in the presence of a hydrogenation catalyst to assist by hydrogenation removal of sulfur and/or nitrogen from the hydrotreated petroleum distillate; fractionating the hydrotreated petroleum distillate by distillation to provide at least one low-boiling blending component consisting of a sulfur-lean, mono-aromatic-rich fraction, and a high-boiling feedstock consisting of a sulfur-rich, mono-aromatic-lean fraction; contacting at least a portion of the high-boiling feedstock with an immiscible phase comprising at least one organic peracid or precursors of organic peracid, in a liquid reaction mixture maintained substantially free of catalytic active metals and/or active metal-containing compounds and under conditions suitable for oxidation of one or more of the sulfur-containing and/or nitrogen-containing organic compounds; separating at least a portion of the immiscible peracid-containing phase from the reaction mixture to recover an essentially organic phase from the reaction mixture; and treating at least a portion of the recovered organic phase with a solid sorbent, an ion exchange resin, and/or a suitable immiscible liquid containing a solvent or a soluble basic chemical compound, to obtain a product containing less sulfur and/or less nitrogen than the feedstock.
Where the oxidation feedstock is a high-boiling distillate fraction derived from hydrogenation of a refinery stream, the refinery stream consists essentially of material boiling between about 200xc2x0 C. and about 425xc2x0 C. Preferably the refinery stream consisting essentially of material boiling between about 250xc2x0 C. and about 400xc2x0 C., and more preferably boiling between about 275xc2x0 C. and about 375xc2x0 C.
Preferably, the immiscible peracid-containing phase is an aqueous liquid formed by admixing, water, a source of acetic acid, and a source of hydrogen peroxide in amounts which provide at least one mole acetic acid for each mole of and hydrogen peroxide. Beneficially, at least a portion of the separated peracid-containing phase is recycled to the reaction mixture.
In another aspect of this invention the treating of recovered organic phase includes use of at least one immiscible liquid comprising an aqueous solution of a soluble basic chemical compound selected from the group consisting of sodium, potassium, barium, calcium and magnesium in the form of hydroxide, carbonate or bicarbonate. Particularly useful are aqueous solution of sodium hydroxide or bicarbonate.
In one aspect of this invention the treating of the recovered organic phase includes use of at least one solid sorbent comprising alumina.
In another aspect of this invention the treating of recovered organic phase includes use of at least one immiscible liquid comprising a solvent having a dielectric constant suitable to selectively extract oxidized sulfur-containing and/or nitrogen-containing organic compounds. Advantageously, the solvent has a dielectric constant in a range from about 24 to about 80. Useful solvents include mono- and dihydric alcohols of 2 to about 6 carbon atoms, preferably methanol, ethanol, propanol, ethylene glycol, propylene glycol, butylene glycol and aqueous solutions thereof. Particularly useful are immiscible liquids wherein the solvent comprises a compound that is selected from the group consisting of water, methanol, ethanol and mixtures thereof.
In yet another aspect of this invention the soluble basic chemical compound is sodium bicarbonate, and the treating of the organic phase further comprises subsequent use of at least one other immiscible liquid comprising methanol.
In other aspects of this invention, continuous processes are provided wherein the step of contacting the oxidation feedstock and immiscible phase is carried out continuously with counter-current, cross-current, or co-current flow of the two phases.
In one aspect of this invention, the recovered organic phase of the reaction mixture is contacted sequentially with (i) an ion exchange resin and (ii) a heterogeneous sorbent to obtain a product having a suitable total acid number.
For a more complete understanding of the present invention, reference should now be made to the embodiments illustrated in greater detail in the accompanying drawing and described below by way of examples of the invention.
The drawing is a schematic flow diagram depicting a preferred aspect of the present invention for continuous production of components for blending of transportation fuels which are liquid at ambient conditions. Elements of the invention in this schematic flow diagram include hydrotreating a petroleum distillate with a source of dihydrogen (molecular hydrogen), and fractionating the hydrotreated petroleum to provide a low-boiling blending component consisting of a sulfur-lean, mono-aromatic-rich fraction, and a high-boiling oxidation feedstock consisting of a sulfur-rich, mono-aromatic-lean fraction. This high-boiling oxidation feedstock is contacted with an immiscible phase comprising at least one organic peracid or precursors of organic peracid, in a liquid reaction mixture maintained substantially free of catalytic active metals and/or active metal-containing compounds and under conditions suitable for the oxidation of one or more of the sulfur-containing and/or nitrogen-containing organic compounds. Thereafter, the immiscible phases are separated by gravity to recover a portion of the acid-containing phase for recycle. The other portion of the reaction mixture is contacted with a solid sorbent and/or an ion exchange resin to recover a mixture of organic products containing less sulfur and/or less nitrogen than the oxidation feedstock. | {
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1. Field of the Invention
This invention relates to compact zoom lenses. Although the invention has general application, it is particularly usable in still photographic cameras.
2. Background Art
U.S. Pat. No. 5,270,867 to Lee R. Estelle, issued Dec. 14, 1993, describes zoom lenses (or zoom lens systems) having two units of lens components--a positive front unit and a negative rear unit. The disclosed zoom lenses utilize only three or four lens components and still achieve very good aberration correction for zoom ranges 1:2 and aperture ratios of f/8 to f/11.
U.S. Pat. No. 4,936,661 to E. I. Betensky et al., issued Jun. 26, 1990, describes a zoom lens with a short back focal length and having, from front to rear, negative, positive and negative optical units. The negative unit closest to the image is movable during zooming to provide a majority of the change in focal length. In some of the examples, the front two units move as a single optical group during zooming, and in others they move relative to each other during zooming. These lenses have remarkable corrections and compactness for their aperture, zoom range and simplicity. The short back focal length makes them particularly useful as zoom objectives in "viewfinder" (non-SLR) cameras.
Many lenses such as zoom lenses of the type described above utilize aspheric surfaces. These aspheric surfaces are generally sensitive to decentering and when decentered, usually introduce image plane tilt which is obviously undesirable. However, without these aspheric surfaces a lens system's performance will be compromised. Thus, there is a need for lenses, and particularly for zoom lenses, with reduced aspheric decenter sensitivity. | {
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1. Field of the Invention
The present invention relates generally to a light reception output controlling apparatus of a photo detector in an optical pickup unit that is configured to guide a laser beam reflected and returned from a disk to the photo detector including a light reception region constituted by a plurality of segments and, more particularly, to a light reception output controlling apparatus of a photo detector in an optical pickup unit that takes measures against an output difference in each light reception output from the photo detector, which is caused by displacement of a light reception spot projected on the light reception region of the photo detector.
2. Description of the Related Art
In an optical pickup unit that optically records and reproduces signals with the use of laser beams to an optical disk such as CD and DVD, an astigmatic method and an application thereof, i.e., a differential astigmatic method are widely used for the focus control that focuses a laser beam irradiated to disk on a signal layer of the disk.
On the other hand, for the tracking control that makes the laser beam irradiated to disk follow a signal track of the disk, one of a three-beam method, a push-pull method, a phase difference method, and applications thereof is employed correspondingly to a disk standard.
For example, an actual example of an optical pickup unit corresponding to various record/reproduction CD as well as DVD-ROM and DVD±R/RW employs the astigmatic method for the various record/reproduction CD and the differential astigmatic method, which is an application of the astigmatic method, for various record/reproduction DVD with regard to the focus control mode and employs the phase difference method for DVD-ROM and a differential push-pull method, which is an application of the push-pull method, for DVD±R/RW and CD with regard to the tracking control mode.
When a basic version and an applied version of the astigmatic method is employed in the focus control, the photo detector includes an astigmatism generation optical system such as an anamorphic lens that generates astigmatism in the reflected laser beam from the disk and a parallel plate disposed in a tilted manner relative to the light axis as well as a light reception region divided into four parts with two orthogonal dividing line forming an angle of 45 degrees relative to the generation direction of the astigmatism.
On the other hand, since three beams are needed for the laser beams irradiated to the disk in the differential astigmatic method of the focus control mode and the differential push-pull method or three-beam method of the tracking control mode, an optical pickup unit employing these modes includes a diffraction grating for diffracting and dividing the laser beam emitted from a semiconductor laser into three beams that are 0th-order light and ±1st-order diffracted light and uses a photo detector including three light reception regions that receives three reflected laser beams, which are these three beams reflected by the disk, as is well known.
By the way, when the optical pickup unit is assembled, the photo detector is positioned and attached to an optical housing disposed with optical devices of the optical pickup unit. See Japanese Patent Application Laid-Open Publication No. 2005-71458.
In the positioning of the photo detector, to obtain appropriate light reception output from each segment constituting the light reception region when a laser spot projected on the light reception region of the photo detector is correctly disposed, a focus error signal and a tracking error signal generated from each light reception output with predetermined calculations is allowed to have S-shaped curve characteristics with suitable symmetric property and amplitude relative to a focus servo and racking servo, and a wobble signal with suitable amplitude is obtained from wobble formed in the DVD recording disk or CD recording disk.
However, although the photo detector is positioned to the optical housing, the laser spot may not be projected correctly on the light reception region of the photo detector because of attachment errors, remaining stress at the time of the attachment, or an application amount output difference and changes over time of the used adhesive, and it is problematic that the focus servo characteristics and tracking servo characteristics may be deteriorated and the amplitude of the wobble signal may be reduced.
In the optical pickup unit employing the differential astigmatic method for the focus control, to take measures to the above problem, it is known to use an offset correction apparatus that corrects an offset based on the position of the light reception spot projected on the light reception region by adjusting a level of a predetermined light reception output relating to the focus error signal such that each light reception output of the four-divided light reception region in the light reception state when the focus error signal becomes “0” (Japanese Patent Application Laid-Open Publication No. 2002-32924).
By the way, in the offset correction apparatus shown in Japanese Patent Application Laid-Open Publication No. 2002-32924, the focus error signal is used, and a configuration including a focus error signal generation circuit that generates the focus error signal by calculating each light reception output of the light reception region of the photo detector, is considered. Since the focus error signal generation circuit is typically built into a disc drive and an apparatus disposed with the focus error signal generation circuit is not shown, the offset correction apparatus is not considered to be self-contained in a single optical pickup unit.
Therefore, unless the disk drive is built into the optical pickup unit, the offset correction is not performed for each light reception output of the four-divided light reception region, and this is difficult to achieve since manufacturers of the optical pickup unit and the disk drive are generally independent from each other.
Although the offset correction apparatus can correct inequality of each light reception output on each diagonal line in the four-divided light reception region generating the focus error signal since the focus error signal is used, inequality is not necessarily corrected in adjacent light reception outputs divided by each dividing line orthogonal to each other in the four-divided light reception region.
Therefore, if the inequality of each light reception output of the four-divided light reception region is corrected by the method using the focus error signal, sufficient effects may not be obtained in improving the amplitude characteristics of the wobble signal or the tracking servo characteristics when the employed tracking control method is the push-pull method or the differential push-pull method that is the application thereof. | {
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This application claims the priority of German application 198 40 186.8, filed Sep. 3, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a laminated glass pane assembly with electrically controllable reflectance, especially for controlling the entry of sunlight and solar heat into vehicles or buildings.
Pane assemblies with controllable transparency are known for example from German Patent Document DE 36 29 879 C2. The disadvantage of this electrochromic pane assembly is that the transmission is controlled by coloration, i.e., by an absorptive operating mechanism. In the colored state, the solar irradiation is absorbed in the coloring layer and therefore, as desired, does not pass directly into the glazed space. However, as a result of the absorption, the pane itself heats up significantly. This results in an undesired time-delayed indirect heating of the space located behind the glass.
One possibility for controlling the reflectance of thin-film assemblies is described in WO 96/38758. The functional layer consists of a rare earth metal hydride layer with a catalyst cover layer. The switching of the reflection is based on the reversible change of the state of hydration of the layer between a metallic highly reflective dihydride phase and a semiconducting trihydride phase with very low reflection. The switching process is triggered by a catalytic gas reaction with gas containing hydrogen. In this type of control, a double pane with a space in between is required, with the optical properties of the functional layer being switched by changing the gas concentration in the space between the panes. Triggering the switching process into the transparent state requires providing or generating a gas containing hydrogen which is conducted into the space between the panes. The reverse reaction into the reflective state can be accomplished for example by flooding the space with air. However, making this a closed assembly is a difficult process. Another disadvantage of this assembly is that a catalyst layer must be made of a metal such as palladium in order to produce the necessary atomic hydrogen from the molecular hydrogen. This catalyst layer limits the maximum possible optical transmission of the entire assembly to 40 percent. These transmission values are insufficient for many applications. Thus for example 70-75 percent transmission is necessary for motor vehicle applications.
The possibility of electrically controlling these functional layers was previously described only as a laboratory experiment (Notten et al., J. Electrochem. Soc., Vol. 143, No. 10, Oct. 1996). The switching process is triggered in an individual layer by the electrolytic decomposition of an alkaline aqueous electrolyte. For a reversibly switchable closed element, this design is not advantageous since the decomposition of the electrolyte occurs irreversibly with the development of a gas.
To increase the reflection values in the visible spectrum, the material of the functional layer described in WO 96/38758 can be alloyed with magnesium (P. van der Sluis, M. Ouwerkerk, P. A. Duine, App. Phys. Lett., 70 (25), 3356 (1997)).
WO 98/10329 A1 describes an optical switching arrangement with the following layer structure:
a glass pane; PA1 an electroreflective functional layer made of an alloy of the hydride of a rare-earth metal and magnesium; PA1 a catalytically active layer that can operate simultaneously as an antioxidation layer made of metals such as palladium or compounds of the AB.sub.2, AB.sub.3 type whose transparency is relatively low (for example, the transparency of palladium is only about 35 to 40 percent); PA1 a proton-conducting solid electrolyte; PA1 a proton storage layer; and PA1 a transparent conducting coating. PA1 a first glass pane; PA1 an electroreflective functional layer consisting of an alloy of the hydride of a rare earth metal and magnesium; PA1 an antioxidation layer consisting of a proton-conducting transparent oxide or fluoride; PA1 an anhydrous proton-conducting solid electrolyte; PA1 a proton storage layer; PA1 a transparent conducting coating; and PA1 a second glass pane.
European Patent Document EP 0 574 791 A2 teaches a polymer electrolyte membrane made of sulfonated polyether ketones for use in fuel cells.
In Japanese Patent Document JP 07-043 753 A an electrochromic cell is described for controlling the incidence of light through a window in which a tantalum oxide layer is provided to protect the electrochromic functional layer against contact with the organic electrolyte.
A goal of the invention is to provide a laminated glass pane that can be switched reversibly in the visible range (especially in the wavelength range between 300 and 800 nm) between highly transparent and reflective states over many switching cycles by applying a low electrical control voltage.
The laminated glass pane assembly according to preferred embodiments of the invention has the following layer structure:
A laminated glass pane assembly according to the invention functions as follows: when an electrical voltage, typically 2 volts, is applied to the transparent conducting coating and to the functional layer so that the minus pole of the voltage source is connected to the functional layer, positively charged protons migrate from the proton storage layer through the solid electrolyte to the functional layer and are neutralized there, creating atomic hydrogen. By a reversible chemical reaction, the atomic hydrogen is stored in the functional layer so that the material of the functional layer changes from a metallic highly reflective state to a semiconducting state with low reflectivity. If the polarity of the electrical voltage is reversed so that the positive pole is connected to the functional layer, protons form and migrate back into the storage layer through the electrolyte. The functional layer is consequently changed back again to a material with a metallic nature. The catalyst layer of the electroreflective functional layer can be eliminated, which is necessary in the known method of gas control since the proton is reduced at the surface to atomic hydrogen which can diffuse directly into the functional layer.
Therefore, the laminated glass pane assembly according to the invention can be switched reversibly under electrical control between a state of high transmission and a state of high reflectivity. Consequently it is possible to regulate the entry of heat into glazed spaces very effectively. At high levels of solar irradiation, overheating of the object is prevented by reflection at the pane. When warming or light is desired, the pane can be switched to the transparent state which makes possible a high degree of transparency to the solar irradiation.
In the laminated glass pane according to the invention with controlled reflectivity, the pane itself remains cool mainly by reflecting the solar radiation energy. As a result, the degree to which energy penetrates the glazing can be regulated very effectively even under long-term irradiation.
Since the functional layer also forms an electrode for electrical control, a homogeneous extensive and rapid switching process is made possible.
Due to the fact that the functional layer is very close to the outside surface within the laminated structure, the assembly achieves a high degree of efficiency.
With the laminated glass pane according to the invention, reversible switching can be achieved over a number of switching cycles. Only low switching energies of less than 1 Wh/m.sup.2 are required for the switching process.
The laminated glass pane assembly according to the invention can be used in particular as glazing for windows of vehicles or buildings. It can also be used however to control light, for example, in headlight assemblies.
The electoreflective functional layer according to the invention consists of an alloy of the hydrides of a rare earth metal, especially yttrium, gadolinium and samarium, and magnesium. The term "electroreflective" in this application describes a layer whose reflectivity can be changed under electrical control. The percentage of rare earth metal or metals preferably is in the range of 20 to 80 percent, for example Y.sub.30 Mg.sub.70. In the case of yttrium, the reversible switching takes place between the metallic dihydride phase YH.sub.2 and the semiconducting trihydride phase YH.sub.3.
The atomic hydrogen required for the switching process is stored in the storage layer as a proton.
Metal oxides, for example cathodically coloring electrochromic layers including in particular tungsten oxide (WO.sub.3) are very well suited for proton storage. When the protons migrate out of the functional layer into such an electrochromic storage layer, they color the latter, such as blue in the case of WO.sub.3. Since this effect is undesired for many applications, it may be advantageous to modify the electrochromic layer in such fashion that only a slight coloration is produced by the proton storage. This is achieved by mixing the tungsten oxide with titanium oxide (TiO.sub.2).
Other materials that are suitable for the proton storage layer are MoO.sub.3, Nb.sub.2 O.sub.5 and V.sub.2 O.sub.5.
The transport of the protons between the storage layer and the electroreflective functional layer takes place through a proton-conducting solid electrolyte. This electrolyte must be anhydrous in order to prevent any damage to the water-sensitive electroreflective functional layer. In one advantageous embodiment, the electrolyte consists of an oligomer or a polymer of sulfonated polyether ketones (PEK, PEEK) with a mobile proton carrier such as imidazole or pyrazole.
In another embodiment, the electrolyte consists of a copolymer of a acrylamidopropane sulfonic acid (AMPS) and another (meth)acrylic derivative, and mobile proton carriers such as imidazole or pyrazole. Especially advantageous is when methoxypolyethyleneglycol(n)monomethacrylate where n=4 to 13, preferably n=9, is used as the (meth)acrylic derivative where n is the number of ethyleneglycol units.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings. | {
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Generally, the transparent conductive film is used as a necessary component of electric/electronic equipments such as means for applying power supply to a display device, a layer for shielding electromagnetic waves of consumer electronics, and a transparent electrode in a variety of display fields such as LCD, OLED, FED, PDP, a flexible display and an electronic paper. Now, as a material of the transparent conductive layer, an inorganic oxide conductive material such as ITO (Indium-Tin oxide), ATO (Antimony-Tin Oxide), AZO (Antimony-zinc Oxide) is used.
If the transparent conductive film is produced by sputtering method, ion beam method, or vapor deposition method which are typically used, it is possible to produce the conductive layer having higher conductivity and excellent transmittance. However, a cost accompanied by provision of vacuum equipments is larger and thus causes mass production and larger scale to be difficult, as well as the transparent substrate such as a plastic film is constricted because it requires low temperature process. In accordance with conditions such as oxygen partial pressure and temperature upon depositing by the sputtering process, the transmittance and resistance of the thin film can be rapidly changed as is changed the composition of the transparent conductive film. Therefore, it was proposed to prepare the transparent conductive film by wet-coating such as spin coating, spray coating, deposit coating, and printing which are suitable for lower cost and large-scale, and then sintering. For example, there is disclosed a transparent conductive film prepared by using metal particles and a binder in Korean Patent Laid-open No. 1999-011487, a composition for the transparent conductive film adding hollow carbon nanofiber into tin oxide in Korean Patent Laid-open No. 1999-064113, and a spray solution for forming a transparent conductive and selective light adsorption film adding neodymium oxide into tin oxide or indium oxide in Korean Patent Laid-open No. 2000-009405. Further, there is disclosed a method of producing a transparent conductive layer forming solution containing metal nanoparticles such as gold and silver.
The surface resistance of the transparent conductive film produced by the above method is as high as 103 to 104 Ω/□ and is increased over time due to changes in the surrounding environment and thus an initial conductivity is not maintained, whereby it is limited to use the transparent conductive film.
Therefore, the inventors can reach the present invention as a result of an effort to solve such problems. That is, the present invention relates to a method for producing the transparent conductive film in a form of complex multi-layer comprising at least one layer using a silver complex compound having special structure and an organic acid metal salt, and in particular to a transparent conductive film which has excellent resistance characteristics and transmittance via a solution process and a method for producing the same. | {
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1. Field of the Invention
The present invention relates to a power source apparatus having a power factor correction circuit function, and particularly to operation in a critical mode of a bridgeless power factor correction circuit of a power source apparatus.
2. Description of the Related Art
Conventionally, in order to supply electric power to a load, a power source apparatus in which an AC (alternating current) voltage from an input AC power source is rectified and then converted to a desired AC or DC (direct current) voltage and supplied to the load has been widely used. In this kind of power source apparatus, a power factor correction circuit needs to be provided in order to correct the power factor and reduce the EMT noise generated by the power source apparatus. Therefore, in a general constitution of a power source apparatus, a rectification circuit consisting of a diode bridge and a power factor correction circuit consisting of a boost converter circuit are installed in the input stage.
In recent years, in a power source apparatus, a so-called bridgeless power factor correction circuit, in which a front stage diode bridge is made unnecessary by combining a power factor correction function by a boost operation and a rectification function, has been proposed (for example, refer to Japanese Patent Application Laid-Open (JP-A) No. 2011-152017). In this power factor correction circuit, the input stage of the power source apparatus can be constituted by a simple circuit and the conduction loss of the diode can be reduced, and thus this kind of power factor correction circuit is advantageous over a constitution in which the rectification circuit and the power factor correction circuit are provided separately. | {
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1. Field of the Invention
This invention relates to neural tissue stimulation and infusion techniques, and more particularly relates to such techniques for treating various disorders, including movement disorders.
2. Description of Related Art
Patients with neurodegenerative diseases or trauma like cerebral infarct or spinal cord injury can have a variety of movement and muscle control problems, like resting, postural, intention or action tremor; dystonia (improper muscle tone); spasticity (undesirable movements, or muscle co-contraction); dyskinesia (poorly executed movements) or involuntary movements like ballismus, choreiform movements and torticollis (inappropriate movements or limb control). Many of these problems can be called hyperkinesia. Although they can be chronic, or worse, progressive, they also may have times of relative remission. Such problems are found, at certain stages, for patients with Parkinson's disease, multiple sclerosis, cerebral palsy, secondary to deafferentation pain, post stroke, post apoplexy or anoxia, post head or spinal trauma, post poisoning, cerebellar disease, etc. Dyskinesia also may result from long term usage of levodopa or other drugs, especially for Parkinson's patients.
Spasticity is defined as a state of excessive muscular tonus (hypertonus) and increased spinal reflexes. This condition exists when the corticospinal pathways have been disrupted. Disruption can occur as a result of stroke causing injury to the fibers as they pass through the internal capsule, a degenerative disorder or physical trauma to the cortex or spinal cord. Loss of this pathway leads to a lack of inhibition of the lower motorneurons which then are more active and responsive to reflexes. In some cases injury to the premotor cortex disrupts the output of the primary motor cortex leading to the similar phenomena.
One form of the Dyskinesia is known as Ballism which typically results in violent flinging movements of the limbs. The movements often affect only one side of the body, in which case the disorder is known as Hemiballism.
In patients suffering essential tremor or tremor due to Parkinson's Disease, the predominant symptom of the disordered movement is tremor. Tremor is often subdivided on the basis of whether the trembling of the limb occurs when the limb is at rest or when muscular contraction is occurring.
Besides being caused by degenerative illness or head injury, tremor can be of unknown origin. One syndrome of idopathic tremor is referred to as essential tremor.
Patients with neurodegenerative diseases or trauma to the basal ganglia like cerebral infarct can have a variety of movement and muscle control problems, like akinesia (impairment in movement initiation), rigidity (stiffness, inflexibility, immobility) or bradykinesia (reduction in amplitude and velocity of movement). These motor disorders may be classified as hypokinetic problems, reflecting an abnormal reduction in voluntary movement. These problems can be chronic, or worse, progressive, but they also may have times of relative remission, especially when drugs are effective. Such problems are common, at certain stages, for patients with Parkinson's disease multiple sclerosis, cerebral palsy, secondary to deafferentation pain, post stroke, post apoplexy or anoxia, post head or spinal trauma, post poisoning, cerebellar disease, etc. Dyskinesia is often a side-effect from medications used for certain symptoms (like tremor, akinesia, rigidity), especially levodopa.
Neurosurgeons have been able to diminish the symptoms of the foregoing movement disorders by lesioning certain brain areas. In addition, it has been demonstrated that open-loop Deep Brain Stimulation (DBS) at high frequencies (100 Hz. or higher) of certain brain structures can alleviate, diminish, or completely stop symptoms of tremor, rigidity, akinesia or hemiballism. Published targets of stimulation include the VIM (ventral intermediate thalamus), subthalamic nucleus, and internal globus pallidus.
It is believed that many symptoms of the foregoing motion disorders are due to dysfunction of the basal ganglia or thalamus. The dysfunction can result in overactivity of the output neurons of the ganglia creating excessive inhibition of the thalamus or underactivity of the ganglia resulting in too little inhibition of the thalamus. If there is too little output activity from the basal ganglia or too little inhibition of the thalamus, a condition such as Ballism or Dystonia will result. If there is too much output activity from the basal ganglia (too much inhibition), a condition such as Hypokinesia will result. | {
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Installing operating system (OS) software on computing devices that have high uptime and reliability requirements results in challenges that must be addressed. Installing the OS software may require that the computing device be rebooted several times, resulting in significant downtime. Further downtime may be incurred when the device is in the midst of an installation process when unnecessary programs or processes interrupt or otherwise slow installation process. For instance, installing an OS on a computing device that includes multiple redundant drives may result in the redundant drives being synchronized one or more times throughout the installation process, ultimately increasing the time required to complete the installation. Additionally, other features, such as power saving modes that may reduce access to various resources of the computing device to save power, may be counterproductive during installation of the OS. Installing an OS quickly and efficiently on the system is a high priority for maintaining uptime and reliable functionality on computing devices. | {
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The huge volume of image and video data available on the networks (e.g., the Internet), scientific databases, and newspaper archives, along with recent advances in efficient (approximate) image matching schemes have opened the door for a number of large scale matching applications. The general field of content based image retrieval (CBIR) uses many different input modalities to search for similar images in a database.
In the realm of freeform hand sketches using interactive displays and a standard drawing interface, if a novice user is asked to sketch a face, the result will typically look rough and unrefined. Similarly, if asked to draw a bicycle, for example, most of users would have a difficult time depicting how the frame and wheels relate to each other.
One solution is to search for an image of the object to be drawn, and to either trace the object or use the object in some other way, such as for a reference. However, aside from the difficulty of finding an image of what is to be drawn, simply tracing object edges eliminates much of the essence of drawing (there is very little freedom in tracing strokes). Conversely, drawing on blank paper with only the image in the mind's eye gives the drawer more freedom. Without significant training it is difficult to get the relative proportions of objects correct. Thus, freehand drawing remains a frustrating endeavor. | {
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The present invention is in the field of optical instruments and more particularly, optical microscopes.
Optical microscopes have long been adapted for viewing objects on planar surfaces of glass slides. Such microscopes generally include an optical system which provides an image of an object in an associated focal plane. A stage, or carrier, assembly holds the object-bearing slide surface substantially parallel to the focal plane of the optics.
Generally, the stage is movable in two perpendicular directions in a plane parallel to the focal plane in order to permit selective movement of a slide mounted on the stage past the field of view of the optics system. In the prior art, these movements are accomplished by mechanical linkages, which, for example, may include ways or bearings. In order to provide relatively high-accuracy control of the movements of the stage, the linkages require precision and correspondingly expensive components. Typically, preloaded mechanical stages may have as much as 50 microns of defocusing motion over a 1-inch by 2-inch slide area. As a result, relatively large ranges of motion are required along the optical axis to provide satisfactory focusing over the range of slide motion. It is known in the prior art to use a vacuum chuck coupled to the stage for supporting a slide against a slide registration surface substantially parallel to the focal plane in an optical microscope, for example, as taught in U.S. Pat. No. 3,848,962. This type of slide mounting apparatus permits satisfactory support for a slide, maintaining the object-bearing surface in a plane parallel to the focal plane for slides having varying wedge or thickness and coverslip thickness.
However, in many applications it is also necessary that an object-bearing slide have a desired alignment which may be repetitively achieved. This is particularly necessary for automated microscopy systems in which a particular location on a slide may be re-accessed a number of times.
It is an object to provide a microscope system which is relatively easy to fabricate at correspondingly low cost.
It is another object of the present invention to provide a microscope system having improved positioning control for object-bearing slides.
It is yet another object to provide a microscope system having an improved method for selectively aligning and supporting a microscope slide. | {
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1. Field of the Invention
The invention relates to processes for preparing synthetic polymeric resins under molecular weight controlling conditions and more particularly relates to processes for controlling the weight average molecular weight of poly-carbonates.
2. Brief Description of Related Art
The preparation of synthetic polymeric resins by the condensation or step-reaction polymerization of one or more monomer reactants is well known and includes the preparation of polycarbonate resins. Generally, the degree of polymerization is controlled by the proportion of at least one reactant in the polymerization. Often the controlling reactant is a compound which, when incorporated into the polymerization reaction, terminates the forming polymer chain. Such compounds are sometimes referred to as "endcappers" or "chain-stoppers." The compounds are in fact molecular weight regulators. Unfortunately, these molecular weight regulators react in the polymerization randomly, i.e., they will terminate chain length propagation haphazardly and not predictably so that the resin products are mixtures of polymer chains of various and random lengths (molecular weights).
By fixing the stoichiometry and reaction conditions, typically in batch preparations, one can usually come close to reproducing batches which are substantially alike in terms of a weight average molecular weight (M.sub.w). However, even these batches show weight average molecular weight (M.sub.w) variation from each other. The problem of eliminating these variations is of commercial importance, since the end user of the resin requires uniformity in physical properties of molded products. Generally, specifications are to be met in terms of molecular weights (M.sub.w).
Those skilled in the art will appreciate the commercial importance of preparing synthetic polymeric resins, which are consistently uniform in their physical properties (especially in regard to weight average molecular weight). One example of an effort to achieve this goal (in respect to polycarbonate preparation) is described in the U.S. Pat. No. 3,240,755 (Cawthon et al., 1966). This Patentee employed in the process fractional extraction with selected solvents which would separate polycarbonate resin chains of differing molecular weights. However, among the separated fractions, there remained considerable variations in the product weight average molecular weights.
The process of the present invention is an improvement in the art, particularly in respect to obtaining consistent weight average molecular weights in a resin product.
We have now found that the weight average molecular weight of a given polycarbonate resin can be controlled and made more homogeneous by addition of reactive multifunctional aliphatic compounds. The weight average molecular weight of batches of polycarbonate can be adjusted to a predetermined value.
Reactive multifunctional aliphatic compounds react with polycarbonate in a non-catalyzed reaction. The amount reacted determines the ultimate weight average molecular weight of the polycarbonate resin batch. The reactive aliphatic compound is converted to a harmless, unreactive, cyclic carbonate. The latter is demonstrated by subjecting the polycarbonate resin product to heat treatment. Heat treatments do not influence the M.sub.w of the product dramatically. The process of the invention can be used to tailor-make resins with specific weight average molecular weight. This would enable one to reduce the inventory of linear polycarbonate resins produced by the interfacial process.
One of the difficulties, prior to this invention, in achieving consistent, narrow weight average molecular weight ranges in the preparation of polycarbonates is related to impurities in the dihydric phenols (I) described above. For example, bisphenol A of even the highest purity includes contaminant compounds which can act as molecular weight regulators (chain stoppers) or their equivalents. Representative of such equivalents are o, p'-bisphenol A, chroman I, spirobindane (6, 6.sup.1 -dihydroxy-3,3,3',3'-tetramethylspiro(bis)indane) and the like which are normally present, in varying quantities, as impurities associated with dihydric phenols like bisphenol A. It is difficult to take into consideration their presence, at the beginning of polymerization because of the variability of their presence. However, they can be accounted for as molecular weight controlling factors during polymerization according to the process of the present invention. | {
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This application makes reference to, incorporates the same herein, and claims all benefits accruing under 35 U.S.C. Section 119 from an application for METHOD FOR DETECTING A HAND-OFF TARGET FREQUENCY IN A CELLULAR MOBILE TELECOMMUNICATION SYSTEM filed earlier in the Korean Industrial Property Office on Mar. 12, 1999 and there duly assigned Ser. No. 8194/1999.
1. Field of the Invention
The present invention relates to a cellular mobile telecommunication system, and more particularly to a method for detecting a hand-off target frequency depending on the availability of radio resources at the base transceiver stations (BTSs) and the location of a mobile station (MS).
2. Description of the Related Art
In a code division multiple access (CDMA) communication system, the whole service area is divided into a plurality of base station coverage areas. Each divided area is defined as a cell and served by a base transceiver stations (BTS). All BTSs are systematically controlled by a mobile switching center (MSC), enabling a roaming MS to maintain the communication link between cells. For greater capacity, each cell is generally divided into several sectors. For example, each cell may be divided into three sectors, xcex1, xcex2, and xcex3, and each sector is provided with a sector antenna for serving the MS.
Referring to FIG. 1, the conventional CDMA communication system comprises a plurality of BTSs 120, 130 and 140 for communicating with the MS 110, a base station controller (BSC) 150 for controlling the BTSs, and a mobile switching center (MSC) 160 for connecting the BSC to another BTS or a public switched telephone network (PSTN). The CDMA system provides a hand-off scheme for maintaining the communication link between an MS and the BTSs when the MS travels from one cell to another.
The CDMA system employs a pseudo-random noise code (PN code) to divide a frequency into multiple code channels, thus serving considerably more subscribers compared to other communication systems such as the frequency division multiple access (FDMA). Basically, all the BTSs of the CDMA communication system employ the same set of frequency channels. However, the BTS located in a dense urban area requires more frequency channels to meet the high demand to serve more subscribers than in other areas. In this case, when an MS communicating with a BTS on a given frequency channel travels to another BTS not having the same frequency channel, the communication channel has be transferred from the current frequency channel of a cell to a different frequency channel of another cell. This is known as a hard hand-off or inter-frequency hand-off. Namely, the hard hand-off replaces the current communication channel with another channel in a different cell so that the MS can maintain the current communication link without interruption.
In the CDMA system, each BTS (or sector) is assigned with a specific pilot signal by which the MS distinguishes each BTS. The MS measures the strength of all the received pilot signals, which are transferred to a BSC through the currently connected BTS. The BSC analyzes the strength of the pilot signals to determine the hand-off and the type of hand-off. This process is called the mobile assisted hand-off (MAHO) because the hand-off is performed based on the signal strength measured by the MS. The IS-95B standard recommendation specifies that the MS would inform the BSC of the time to perform the inter-frequency hand-off as well as the environment of the hand-off target frequency (i.e., the strength of the pilot signal). Accordingly, the MS periodically or upon detecting the target frequency specified by the BSC, based on which the BSC determines whether the target BTS should perform the inter-frequency hand-off. However, when the target BTS has no reserved radio resource that can be assigned to the target frequency, the MS cannot help but lose the current communication connection. For this reason, the MS must often search for another target frequency to assist the hand-off which increases the load on the MS, causing communication link failure or power control failure.
It is an object of the present invention to provide a method for detecting a target frequency to provide an inter-frequency hand-off in a CDMA communication system, thus increasing the success rate of hand-off while minimizing the number of attempts searching for the alternate hand-off target frequency.
According to one embodiment of the present invention, a method for detecting a hand-off target frequency of an MS in a CDMA communication system, comprising the steps of transmitting a pilot strength measurement message (PSMM) from an MS to a BSC through at least one BTS; causing the BSC to determine based on the received PSMM whether the MS is located in the border region of a BTS or whether the forward radio communication channel of the MS is in bad state; causing the BSC to command the MS to detect a specific hand-off target frequency when the MS is located in the border region of the BTS or when the forward radio communication channel is in bad state; causing the MS to report all the BTSs providing the specified hand-off target frequency to the BSC; causing the BSC to perform the inter-frequency hand-off based on the reported target BTSs from the MS; causing the BSC to check whether the MS, while detecting the hand-off target frequency, meets the requirement of stopping the detection for the hand-off target frequency; causing the BSC to command the MS to stop the detection for the hand-off target frequency when meeting the requirement; and causing the MS to stop the detection.
According to another embodiment of the present invention, a method for detecting an inter-frequency hand-off target frequency by an MS in a CDMA communication system, comprising the steps of classifying the frequency channels of the BTSs as a xe2x80x9csufficient frequency resource statexe2x80x9d if these frequency channels are available for a new call assignment or a hand-off; classifying the frequency channels of the BTSs as an xe2x80x9cinsufficient frequency resource statexe2x80x9d if these frequency channels are substantially available and has a probability of failing the assignment of a channel during the periodic detection of a inter-frequency hand-off target frequency; classifying the frequency channels of the BTSs as a xe2x80x9cconsumed frequency resource statexe2x80x9d if these frequency channels are unavailable; detecting common frequency commonly provided by the BTSs listed in the active set; selecting one of the detected common frequencies as the target frequency that renders all the BTSs to be in the xe2x80x9csufficient frequency resource statexe2x80x9d; if there is no common frequency that renders all the BTSs to be in the xe2x80x9csufficient frequency resource statexe2x80x9d, excluding any common frequency corresponding to the xe2x80x9cconsumed frequency resource statexe2x80x9d; selecting a common frequency from the remaining detected frequencies as the target frequency that renders relatively more BTSs to be in the xe2x80x9csufficient frequency resource statexe2x80x9d; and, if no common frequency that renders relatively more BTSs to be in the xe2x80x9csufficient frequency resource statexe2x80x9d, selecting a common frequency from the remaining detected frequencies as the target frequency which renders relatively more BTSs to be in the xe2x80x9cinsufficient frequency resource statexe2x80x9d as the target frequency.
According to still another embodiment of the present invention, the method for performing an inter-frequency hand-off of an MS by a BSC in a CDMA communication system, comprising the steps of classifying the frequency channels of the BTSs as a xe2x80x9csufficient frequency resource statexe2x80x9d if these frequency channels are available for a new call assignment or a hand-off; classifying the frequency channels of the BTSs as an xe2x80x9cinsufficient frequency resource statexe2x80x9d if these frequency channels are substantially available and has a probability of failing the assignment of a channel during the periodic detection of a inter-frequency hand-off target frequency; classifying the frequency channels of the BTSs as a xe2x80x9cconsumed frequency resource statexe2x80x9d if these frequency channels are unavailable; detecting common frequency commonly provided by the BTSs listed in the active set; causing the MS to detect and report all target BTSs providing the target frequency, as specified by the BSC, as well as the strength of pilot signals from the target BTSs; causing the BSC to determine whether to perform the inter-frequency hand-off of the MS according to the report received from the MS; checking whether the target frequency of the target BTSs is in the xe2x80x9cconsumed frequency resource statexe2x80x9d if the MS requires the inter-frequency hand-off; performing the inter-frequency hand-off to the target frequency if no target BTS has the target frequency in the xe2x80x9cconsumed frequency resource statexe2x80x9d; checking whether the target BTS has the maximum pilot strength when it has the target frequency in the xe2x80x9cconsumed frequency resource statexe2x80x9d; performing the inter-frequency hand-off of the MS to the remaining target BTSs while excluding the target BTS in the xe2x80x9cconsumed frequency resource statexe2x80x9d if the target BTS does not have the maximum pilot strength; and, commanding the MS to detect a new target frequency selected when the BTS with the target frequency in the xe2x80x9cconsumed frequency resource statexe2x80x9d has the maximum pilot strength.
According to a further embodiment of the present invention, a method for detecting an inter-frequency hand-off target frequency by an MS in a CDMA communication system, comprising the steps of classifying the frequency channels of the BTSs as a xe2x80x9csufficient frequency resource statexe2x80x9d if these frequency channels are available for a new call assignment or a hand-off; classifying the frequency channels of the BTSs as an xe2x80x9cinsufficient frequency resource statexe2x80x9d if these frequency channels are substantially available and has a probability of failing the assignment of a channel during the periodic detection of a inter-frequency hand-off target frequency; classifying the frequency channels of the BTSs as a xe2x80x9cconsumed frequency resource statexe2x80x9d if these frequency channels are unavailable; detecting common frequency commonly provided by the BTSs listed in the active set; causing a BTS to report to the BSC that it has no frequency resource for a new assignment in the particular frequency channel assigned to itself; causing the BSC to set the BTS as a xe2x80x9cconsumed frequency resource statexe2x80x9d; and causing the BSC to command the MS to detect another target frequency.
The present invention will now be described more specifically with reference to the drawings attached only by way of example. | {
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The Digital Signature Algorithm (DSA) and the Elliptic Curve Digital Signature Algorithm (ECDSA) are described in the standards FIPS PUB 186-3 (U.S. Department of Commerce) and ANS X9.62-2005 (American National Standard for Financial Services), both of which are herein incorporated by reference in their entirety. These signature algorithms use public-key cryptography to enable the creation and verification of digital signatures on digital messages. Signatories in DSA and ECDSA possess a private key and a public key; the private key is used to generate a digital signature (i.e., to sign a message) and the public key is used by third parties to validate that signature.
DSA and ECDSA are widely deployed (e.g., in ssh, SSL/TLS, Canada Post digital postmarks, DTCP, AACS, MS-DRM) and can be used to provide data origin authentication, data integrity, and non-repudiation. However, any assurances that DSA and ECDSA signatures might provide are always subject to the assumption that a signatory's private key remains private (i.e., the private key does not leak to an attacker).
The following references provide additional background information, and are each incorporated by reference in their entirety: [1] American National Standard for Financial Services, ANS X9.62-2005, Public Key Cryptography for the Financial Services Industry, The Elliptic Curve Digital Signature Algorithm (ECDSA), 16 Nov. 2005. [2] D. Hankerson, A. Menezes, S. Vanstone, Guide to Elliptic Curve Cryptography, 2003. [3] Information Technology Laboratory, National Institute of Standards and Technology, FIPS PUB 186-3, Digital Signature Standard (DSS), June 2009. [4] Standards for Efficient Cryptography, SEC 1: Elliptic Curve Cryptography, Version 2.0, 21 May 2009. [5] National Security Agency, NSA Suite B Cryptography, available from http://www.nsa.gov/ia/programs/suiteb_cryptography/ [6] Digital Transmission Content Protection Specification, Volume 1 (Informational Version), Revision 1.51, 1 Oct. 2007.
The signature generation operation of ECDSA and DSA is typically implemented in computer software, which is then run on a particular computing device (e.g., a cell phone, set-top box, smart card). In many applications, this operation takes place in an environment outside the signatory's control—possibly in the presence of adversaries (i.e., an adversary might observe the device as a signature is being computed).
An adversary who analyzes only the inputs and outputs of signature generation effectively treats that implementation like a black box. DSA and ECDSA were designed to resist such black box attackers. However, there is often more information available than just inputs and outputs. Additional information such as device power consumption, execution time, electromagnetic emanations, and response to data faults can give clues to an attacker about the execution of the software; it has been shown that this can leak bits of the private key and completely compromise the signature scheme.
A much more robust security model considers resistance against white box attackers. White box attackers have full visibility into the execution of the software that computes the signature. Resistance against white box attackers is a highly desired goal, but no white box implementations of DSA or ECDSA have yet been proposed.
As a concrete example of this problem, consider the DTCP protocol used to protect audio/video content. The following quotation comes from the DTCP specification, as defined in reference [6] above: | {
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1. Field of the Invention
This invention relates to radio communications networks. More particularly, this invention relates to planning and management of dynamic communications networks based upon propagation forecasting, modeling techniques and the ability to adapt the network according to continually updated propagation and traffic forecasting.
2. Description of the Prior Art
A major problem in the field of radio communications is caused by the environment and its effects on network performance, making these elements significant network planning factors. Meteorological phenomena that affect the propagation reliability of communications links include, depending on the radio frequency of the link, atmospheric refraction, layering (ducting), rain, absorption and fog. Examples of environmental phenomena effecting communications reliability include fading caused by clear-air atmospheric layering on microwave links, rain attenuation on millimeter wave links and attenuation by fog of optical links. These changeable environmental factors have a profound impact on the dynamic networks used by the U.S. Army for tactical communications.
Independent of such harsh environmental factors, both the configuration and geographical location of these networks can change on a daily or even hourly basis. Combining the harsh environmental effects of phenomena such as fading, rain attenuation and attenuation by fog with the changeable configuration and geographical location of the U.S. Army's tactical communications networks can seriously degrade anticipated network performance. A stationary communications network for long-term use can be readily designed based on typical, historical local weather patterns and their effect on propagation, however, a moveable communications network operating in different climates must be tailored to local conditions that exist at the time of use.
Traditional propagation reliability methods are based on long-term historical meteorological statistics. While propagation forecasting has undergone improvement in recent years, communications network planning and management today is not based upon the known weather forecast and its probable effect on radio propagation. See for example, A Regression Model for Forecasting Microwave Radio Fading at Palmetto, Georgia, J. A. Schiavone and S. H. Hermiller, IEEE Transactions on Antennas and Propagation, Vol. AP-34, No. 7, pp. 936-942, July 1986.
There have been advances in terms of propagation and reliability modeling during fading using historical statistics resulting in a propagation reliability model for tactical line-of-sight radio which has been developed for a large range of climates, terrains, fade margins and path lengths. See, for example, Line-of-Sight Radio Fading Prompts Remedial Program, K. H. Brockel and A. Vigants, SIGNAL Magazine, November 1992. While the effects of weather on propagation are well known, up to now there have been no practical solutions for quickly calculating the propagation effects from predicted short-term weather conditions and then rapidly adjusting the network plan or components of a communications system to meet given network performance parameters.
Up to now, the effects of weather and communications-traffic patterns on the communications quality of dynamic networks are typically either anticipated based upon historical data, or compensated for by man-calculated adjustments to networks in the field. Current tactical network management systems, based on traditional traffic engineering using long-term traffic performance statistics or rules of thumb, do not provide a facility for automatically planning and engineering communications networks based on current traffic forecasts and the real-time analysis of current traffic loads. Tactical networks cannot be planned in this manner because they are continually dynamic. In a tactical environment, a battlefield commander needs to design a communications network based on tonight's or tomorrow night's weather if that is the scheduled time of the military operation. Those concerned with the planning and management of communications networks in either a tactical or commercial environment have long recognized a need for an automated method to plan a communications system based on anticipated weather, propagation patterns and network traffic, monitor and calculate the impact of such environmental changes on the network quickly and then adjust the communications network for optimized performance based upon these environmental changes.
This invention fulfills that long-recognized need by providing an automated method of network planning and management which will automatically plan, engineer and direct the installation and continuing operation of a radio communications network based upon planning tools integrating the effects of forecast weather, environmental feedback, real-time network status and necessary traffic dimensions, a dynamic network model and automatic experience-based improvements of algorithms used in the dynamic network model. An automated communications network planner is also provided.
The present invention addresses the practical needs of the tactical network planner and manager by using near-future propagation forecasts for network planning and real-time propagation information for network management, with an emphasis on 24-hour forecasting because many meteorological phenomena have a diurnal (24-hour) cycle. By utilizing updated weather, performance and traffic data received from the network, with the aid of artificial intelligence (AI) techniques, necessary environment-driven changes can be made continuously and on a real-time basis operating on large masses of data which only a computer can effectively handle. Further, this invention utilizes tools such as computer models, algorithms, computer simulations and AI-based tools in a new way along with currently available tactical system/network management technology.
While this invention may be readily used in tactical military communications systems, there are numerous commercial applications in areas such as mobile or cellular telephones, as well as any communications system that can be incapacitated by adverse propagation conditions. A key aspect of the method and apparatus of this invention is the ability to use and automatically update propagation, weather and traffic algorithms so that the communications system can automatically send reconfiguration "change orders" to the network to compensate for the harmful effects of these phenomena.
Examples of propagation forecasting tools may be found in the following references:
"24-Hour Network Performance Management System Technical Paper," Jan. 21, 1993, U.S. Army CECOM Space and Terrestrial Communications Directorate Line-of-Sight Propagation Reliability Working Group; PA0 Michael J. Harrigan, Kenneth H. Brockel, William P. Sudnikovich, Arvids Vigants, William T. Barnett, Stanley Conway-Clough, Richard Wood, Robert Edwards, Joli Toth and Julius Sunshine "24-Hour Network Performance Management System," MILCOM 94 Conference Technical Paper, Fort Monmouth, N.J., Oct. 2-5, 1994; PA0 "Rain Propagation Reliability Forecasting Method Technical Memorandum," May 17, 1993, U.S. Army CECOM Space and Terrestrial Communications Directorate Line-of-Sight Propagation Reliability Working Group; and PA0 Network Management Tool Detailed Operational Concepts Document, Jan. 5, 1994. U.S. Army CECOM Space and Terrestrial Communications Directorate Network Management Automation & Integration Working Group. Further, an example of a propagation reliability model may also be found in U.S. Pat. No. 5,669,063, entitled "Method of Establishing Line of Sight Propagation," which was issued as on Sep. 16, 1997, which is hereby incorporated by reference, in which Messrs. Brockel and Sudnikovich are also co-inventors of this invention. PA0 Eric C. Ericson, Lisa Traeger Ericson, and Daniel Minoli, "Expert Systems Applications in Integrated Network Management," Artech House, Inc., 1989; PA0 "MIL-STD-2045-38000, Network Management for DOD Communications (Draft)," January 4, 1993; PA0 V. J. Procopio, Kenneth H. Brockel, Joseph R. Inserra, Francis G. Loso, Paul A. Major, Kenneth D. Chaney, Robert J. Locher, Arvids Vigants, Mark Riehl and William T. Barnett, "Tactical Line-of-Sight Radio Propagation Reliability Modeling," MILCOM 93 Conference Technical Paper, Boston, Mass., Oct. 11-14, 1993; and PA0 K. H. Brockel, Tommy Cheng and MAJ Michael Mitchum, "NPT--A Success Story Evolving From Teamwork and Innovation," MILCOM 93 Conference Technical Paper, Boston, Mass., Oct. 11-14, 1993.
Examples of systems or devices which manage communications networks may be found in the following references: | {
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1. Field of the Invention
The present invention relates to a sheet feeding apparatus for feeding a sheet and an image forming apparatus for recording image information on the fed sheet and, more specifically, to a sheet conveying apparatus which adapts a sheet feeding pressure to a sheet size or a loaded weight.
2. Description of the Related Art
In the fields of image forming apparatuses such as a copying machine, a facsimile machine, and a printer, a sheet feeding apparatus has a sheet storing device such as a sheet tray on which a sheet is loaded and which stores a sheet. A sheet loading plate on which a sheet stack is loaded and supported is arranged in the housing of the sheet storing device. A pickup roller (sheet feeding roller) is arranged above the sheet loading plate such that the pickup roller is brought into contact with the uppermost sheet. The sheet loading plate is biased by a biasing spring lifts up the sheet stack to press the uppermost sheet against the pickup roller. In this case, a force of pressing the sheet stack against the pickup roller is called a sheet feeding pressure hereinafter. When a rotating power is transmitted to the pickup roller, a rotation frictional force of the roller and a bias spring force from the lower side generate a sheet feeding pressure. In this manner, the uppermost sheets are sequentially fed and conveyed to the image formation device.
As a known means which generates a sheet feeding pressure, in addition to a biasing spring, a structure in which a lifting mechanism constituted by a drive motor and the like is moves upwardly to lift a sheet loading plate to a position at a level of a conveyance path level to bring a pickup roller into press contact with the uppermost sheet by a spring is known.
Since the structure which obtains the sheet feeding pressure by a biasing spring is simple and inexpensive, the structure is often used in the field of a low-speed-processing image forming apparatus having a sheet tray and a sheet cassette in which a capacity of loaded sheets is 25 or less. On the other hand, in the latter structure in which a sheet feeding pressure is obtained by a lifting mechanism, a constant sheet feeding pressure can be always obtained regardless of a sheet live load, and a large number of sheets can be loaded and stored. However, the number of parts increases, and a control mechanism which lifts the sheet loading plate up is required to increase the cost. For this reason, the structure is used in the field of an image forming apparatus which performs relatively high speed processing.
The sheet feeding pressure can be expressed by a value obtained by subtracting an additional value between a sheet loading weight and the weight of the sheet loading plate from a push-up force acting on the sheet loading plate. When the push-up force obtained by the biasing spring is excessively large more than necessary, so-called multi feeding easily occurs such that several sheets are conveyed by a pickup roller at once. On the other hand, when a push-up force generated by a biasing spring is small not to obtain a necessary sheet feeding pressure, the pickup roller slips on the uppermost sheet and cannot feed out the sheet to easily cause non-feeding.
In a sheet cassette which copes with a relatively small capacity of 250 loaded sheets or less, a change in weight caused by the number of sheets is small. For this reason, it is relatively easy to appropriately adjust or set a sheet feeding pressure. However, in a large-capacity sheet cassette on which 500 sheets can be loaded, the following problem occurs. A change in weight caused by the number of loaded sheets is large. Furthermore, when a so-called universal cassette which can cope with several types of sheets having different sizes is used, a difference in weight between a sheet of the maximum size and a sheet of the minimum size is so large that appropriate setting of a sheet feeding pressure is very difficult.
A sheet feeding pressure generated by using a biasing spring, as shown in a characteristic graph in FIG. 7, exhibits an almost linear characteristic from a full load condition to a feeding condition of a last sheet regardless of sheet sizes. In this case, for example, setting is performed in accordance with a sheet feeding pressure obtained in a full load condition of sheets having a maximum size, i.e., A3, a sheet feeding pressure coping with a full load condition of sheets of minimum sizes, i.e., B5R is excessively large more than necessary. As a result, when a sheet of a size B5R is sent, multi feeding easily occurs.
In contrast to this, as shown in a characteristic graph in FIG. 8, when a sheet feeding pressure is set in accordance with a full load condition of size B5R sheets, a sheet feeding pressure in a full load condition of size A3 sheets, a sheet feeding pressure in the full load condition of size A3 sheets is short to make it impossible to feed the sheets. More specifically, it is impossible to obtain a sheet feeding pressure adapting to a full load condition of sheets having different sheet sizes to a last-sheet-feeding condition by a single biasing spring having a constant spring strength (spring constant).
In order to solve the problem, for example, in Japanese Patent Application Laid-open No. 9-30663, the following configuration is proposed. For example, in Japanese Patent Application Laid-open No. 9-30663, several types of biasing springs having different spring strengths are prepared, and the spring strengths are changed in accordance with at least one biasing spring for each of the different types of sheets. Japanese Patent Application Laid-open No. 61-22647 proposes the following configuration. An inclined guide unit is arranged on the lower surface of a sheet loading plate to displace a contact portion of a spring depending on a sheet width, so that a sheet feeding pressure is kept almost constant.
However, as in an invention described in Japanese Patent Application Laid-open No. 9-30663, when several types of springs are prepared for respective sheets of different sizes, another dedicated member such as a pressure-adjusting arm must be arranged for each spring to change a spring strength depending on a sheet size. For this reason, in addition to an increase in number of parts or an increase in cost caused by preparing several types of springs, an apparatus is complicated due to the pressure-adjusting arm or the like, and management of accuracy of spring strengths becomes very difficult.
As described in Japanese Patent Application Publication No. 61-22647, when the inclination guide device is arranged on the lower surface of the sheet loading plate to change the contact portion of the biasing spring depending on sheet widths, a space for the inclination must be counted in a direction of height of the sheet cassette. As a result, the sheet cassette increases in size to increase in size of the apparatus. Since a compression coil spring is used as a biasing spring, a guide member for guiding an extension/contraction operation must be independently arranged. At the same time, a parts cost and a manufacturing cost are disadvantageously increased by an increase in number of parts. | {
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Palladium and palladium alloys have been traditionally used as contact surfaces for electrical contacts and connectors. Primarily, these alloys have been used in the form of wrought alloys or clad inlays as a replacement for gold in such applications. In recent years, many manufacturers of electrical contacts and connectors have been seeking methods to electroplate palladium or palladium alloys since, in many applications, electroplating would be more economical.
Many electrical contacts are manufactured by first electroplating a precious metal deposit in the form of a narrow band or stripe onto a wider strip or surface area of basis metal using high speed, reel-to-reel plating equipment. The electoplated strip is then stamped and formed into a contact with the precious metal electrodeposit located at the exact point where contact is to be made with the mating part. The electrodeposit on this formed part must be tightly adherent, sound, crack-free, and porosity-free, even after the stamping and forming operations. In order for an electrodeposit to withstand such operations, it must have sufficient ductility, good adhesion to the base metal, and freedom from porosity in the electroplated condition. Cracking of the electrodeposits cannot be tolerated in the final product. The electrodeposit should have sufficient ductility to withstand the stresses of stamping and forming without producing further cracks, pores or peeling from the substrate.
U.S. Pat. No. 4,269,671 discloses a method for electrodepositing a 60% by weight palladium 40% by weight silver alloy from a highly acidic solution containing a large amount of chloride ion. While the alloy obtained is a sound deposit, the plating solution is highly corrosive and causes severe displacement reactions to take place between the plating solution and the basis metal to be plated. These basis metals generally indude copper, nickel or their alloys. This type of high chloride plating solution for palladium/silver alloys as well known in the art as evidenced by Canadian Pat. No. 440,591. U.S. Pat. No. 4,269,671 discloses that the copper or nickel basis metals can be protected from the highly corrosive nature of such high chloride plating baths by first coating the basis metal with a thin layer of a precious metal. The precious metals suggested are silver and soft gold with the latter being preferred.
U.S. Pat. No. 4,463,060 describes a permanently solderable palladium/nickel electrodeposit of a thickness of about 0.1 to 1.5 micrometers having about 46 to 82 atomic percent palladium, balance nickel. This layer is covered by an extremely thin (i.e., about 20 angstroms) second layer of almost pure palladium. The second layer of palladium is formed not by electroplating, but by dipping the first layer into a solution of sulfuric or hydrochloric acid. This combination is described as forming a permanently solderable palladium/nickel electrodeposit. | {
"pile_set_name": "USPTO Backgrounds"
} |
Digital circuits may comprise digital filters to convert input data of a first frequency clock to output data of a second frequency clock. For the case of an interpolation filter the input data has a lower frequency clock than the output data, while in a decimation filter the input data has a higher frequency clock than its output data. Digital filters thus may comprise multiple stages operating at different frequency clocks. | {
"pile_set_name": "USPTO Backgrounds"
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According to the theory of signal transmission, the demodulation of a signal corresponds to the mixing of the modulated signal with the sampling signal, and then the integration of the resulting product. The corresponding mixing step may be done using mixer circuits.
The basic element for many mixer circuits is a dual-gate transistor. An example of such a mixing circuit is presented by Sullivan et al. in “Doubly Balanced Dual(g)ate CMOS Mixer”, IEEE Journ. Of Solid-State Circ., Vol. 34, No. 6, 1999. The combination of at least four dual-gate transistors leads to a double balanced mixer for very high frequencies in the GHz range. Another example of an electronic mixer circuit based on dual-gate transistors is presented in U.S. Pat. No. 4,603,436 A (Butler, “Microwave Double Balanced Mixer”, 1986).
The above-mentioned mixer circuits have the disadvantage that several dual-gate transistors are required with additional load resistors, low-pass filters or differential amplifiers, which leads to a relatively complex circuit. Moreover, the size of the circuits does not allow the implementation as elements in a high-density array, such as, e.g., in the pixel structures of image sensors. Furthermore, for the intermediate frequency (IF) signal, an integration process of the IF signal would be required after the mixing process. As the number of phases would define the number of additional mixing elements, the required chip area increases. Furthermore, the mixing circuit is not useful for the mixing of very small modulated currents such as, e.g., photo-currents, because the mixing process is performed in the current domain instead of the less noisy charge domain.
In the publication EP-0'837'556 A1 (Wang, “Four terminal RF mixer device”, 1997) a so-called four-terminal-radio frequency (RF) mixer is described based on a MOS transistor having drain, source, gate and back-gate contacts. The radio-frequency (RF) signal and the local-oscillator (LO) signal are applied to the gate and back-gate contacts, respectively. A current flowing from the source to the drain of the transistor corresponds to the mixing result delivering the intermediate frequency (IF) signal. The disclosed mixing process has been reduced to only one transistor element and an additional load circuit. Different embodiments allow for partial and double balanced/unbalanced mixing, respectively. Although the basic mixing element has already been reduced to very compact size, the double balanced mixing still needs at least four discrete transistors of which each requires a gate, a source diffusion, a drain diffusion and an additional well implant. An in-phase/quadrature (I/Q) mixing circuit would look similar with only the signals being slightly different. The complex circuit consisting of many mixing transistors implies relatively large chip sizes to be used. Additionally, the four transistors have to match with high accuracy for the demodulation of very small input signals. Hence, the requirements put on the fabrication process are demanding and may reduce the expected fabrication yield dramatically.
In the field of demodulation devices, photo-sensitive sensors are known which use a device enabling the demodulation of the light waves. Such devices are described in the publications DE-44'40'613 C1, GB-2'389'960 A (Seitz, “Four-tap demodulation pixel”) and in the European patent application No. 04'405'489 (Büttgen et al., “Large-area pixel for use in an image sensor”). All these devices are directed to photo-currents with low intensities. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates generally to a system and method for oxygenating blood, and more particularly, to a system and method for providing oxygenated blood, e.g., hyperoxemic or hyperbaric blood, to a patient.
Oxygen is a crucial nutrient for human cells. Cell damage may result from oxygen deprivation for even brief periods of time, which may lead to organ dysfunction or failure. For example, heart attack and stroke victims experience blood flow obstructions or diversions that prevent oxygen from being delivered to the cells of vital tissues. Without oxygen, the heart and brain progressively deteriorate. In severe cases death results from complete organ failure. Less severe cases typically involve costly hospitalization, specialized treatments and lengthy rehabilitation.
Blood oxygen levels may be described in terms of the concentration of oxygen that would be achieved in a saturated solution at a given partial pressure of oxygen (pO2). Typically, for arterial blood, normal blood oxygen levels (i.e., normoxia or normoxemia) range from 90-110 mm Hg. Hypoxemic blood (i.e., hypoxemia) is arterial blood with a pO2 less than 90 mm Hg. Hyperoxic blood (i.e., hyperoxemia or hyperoxia) is arterial blood with a pO2 greater than 400 mm Hg (see Cason et. al (1992) Effects of High Arterial Oxygen Tension on Function, Blood Flow Distribution, and Metabolism in Ischemic Myocardium, Circulation, 85(2):828-38, but less than 760 mm Hg (see Shandling et al. (1997) Hyperbaric Oxygen and Thrombolysis in Myocardial Infarction: The xe2x80x9cHOT MIxe2x80x9d Pilot Study, American Heart Journal 134(3):544-50). Hyperbaric blood is arterial blood with a pO2 greater than 760 mm Hg. Venous blood typically has a pO2 level less than 90 mm Hg. In the average adult, for example, normal venous blood oxygen levels range generally from 40 mm Hg to 70 mm Hg.
Blood oxygen levels also might be described in terms of hemoglobin saturation levels. For normal arterial blood, hemoglobin saturation is about 97% and varies only slightly as pO2 levels increase. For normal venous blood, hemoglobin saturation is about 75%.
In patients who suffer from acute myocardial infarction, if the myocardium is deprived of adequate levels of oxygenated blood for a prolonged period of time, irreversible damage to the heart can result. Where the infarction is manifested in a heart attack, the coronary arteries fail to provide adequate blood flow to the heart muscle.
Treatment of acute myocardial infarction or myocardial ischemia often comprises performing angioplasty or stenting of the vessels to compress, ablate or otherwise treat the occlusion(s) within the vessel walls. For example, a successful angioplasty uses a balloon to increase the size of the vessel opening to allow increased blood flow.
Even with the successful treatment of occluded vessels, a risk of tissue injury may still exist. During percutaneous transluminal coronary angioplasty (PTCA), the balloon inflation time is limited by the patient""s tolerance to ischemia caused by the temporary blockage of blood flow through a vessel during balloon inflation. Reperfusion injury also may result, for example, due to slow coronary reflow or no reflow following angioplasty.
For some patients angioplasty procedures are not an attractive option for the treatment of vessel blockages. Such patients typically are at increased risk of ischemia for reasons such as poor left ventricular function, lesion type and location, or the amount of the myocardium at risk. The treatment options for such patients thus include more invasive procedures such as coronary bypass surgery.
To reduce the risk of tissue injury typically associated with treatments of acute myocardial infarction and myocardial ischemia, it is usually desirable to deliver oxygenated blood or oxygen-enriched fluids to at-risk tissues. Tissue injury is minimized or prevented by the diffusion of the dissolved oxygen from the blood or fluids to the tissue and/or blood perfusion that removes metabolites and that provides other chemical nutrients.
In some cases, the desired treatment of acute myocardial infarction and myocardial ischemia includes perfusion of oxygenated blood or oxygen-enriched fluids. During PTCA, for example, tolerated balloon inflation time may be increased by the concurrent introduction of oxygenated blood into the patient""s coronary artery. Increased blood oxygen levels also may cause the normally perfused left ventricular cardiac tissue into hypercontractility to further increase blood flow through the treated coronary vessels.
The infusion of oxygenated blood or oxygen-enriched fluids also may be continued following the completion of PTCA treatment or other procedures (e.g. surgery) wherein cardiac tissue xe2x80x9cstunningxe2x80x9d with associated function compromise has occurred. In some cases continued infusion may accelerate the reversal of ischemia and facilitate recovery of myocardial function.
Conventional methods for the delivery of oxygenated blood or oxygen-enriched fluids to at-risk tissues involve the use of blood oxygenators. Such procedures generally involve withdrawing blood from a patient, circulating it through an oxygenator to increase blood oxygen concentration, and then delivering the blood back to the patient. One example of a commercially available blood oxygenator is the Maxima blood oxygenator manufactured by Medtronic, Inc., Minneapolis, Minn.
There are drawbacks, however, to the use of a conventional oxygenator in an extracorporeal circuit for oxygenating blood. Such systems typically are costly, complex and difficult to operate. Often a qualified perfusionist is required to prepare and monitor the system.
Conventional oxygenator systems also typically have a large priming volume, i.e., the total volume of blood contained within the oxygenator, tubing and other system components, and associated devices. It is not uncommon in a typical adult patient case for the oxygenation system to hold more than one to two liters of blood. Such large priming volumes are undesirable for many reasons. For example, in some cases a blood transfusion may be necessary to compensate for the blood temporarily lost to the oxygenation system because of its large priming volume. Heaters often must be used to maintain the temperature of the blood at an acceptable level as it travels through the extracorporeal circuit. Further, conventional oxygenator systems are relatively difficult to turn on and off. For instance, if the oxygenator is turned off, large stagnant pools of blood in the oxygenator might coagulate.
In addition, with extracorporeal circuits including conventional blood oxygenators there is a relatively high risk of inflammatory cell reaction and blood coagulation due to the relatively slow blood flow rates and the large blood contact surface area. A blood contact surface area of about 1-2 m2 and velocity flows of about 3 cm/s are not uncommon with conventional oxygenator systems. Thus, relatively aggressive anti-coagulation therapy, such as heparinization, is usually required as an adjunct to using the oxygenator.
Perhaps one of the greatest disadvantages to using conventional blood oxygenation systems is that the maximum partial pressure of oxygen (pO2) that can be imparted to blood with commercially available oxygenators is about 500 mm Hg. Thus, blood pO2 levels near or above 760 mm Hg cannot be achieved with conventional oxygenators.
Some experimental studies to treat myocardial infarction have involved the use of hyperbaric oxygen therapy. See, e.g., Shandling et al. (1997), Hyperbaric Oxygen and Thrombolysis in Myocardial Infarction: The xe2x80x9cHOT MIxe2x80x9d Pilot Study, American Heart Journal 134(3):544-50. These studies generally have involved placing patients in chambers of pure oxygen pressurized at up to 2 atmospheres, resulting in systemic oxygenation of patient blood up to a pO2 level of about 1200 mm Hg. However, use of hyperbaric oxygen therapy following restoration of coronary artery patency in the setting of an acute myocardial infarction is not practical. Monitoring critically ill patients in a hyperbaric oxygen chamber is difficult. Many patients become claustrophobic. Ear damage may occur. Further, treatment times longer than 90 minutes cannot be provided without concern for pulmonary oxygen toxicity.
For these reasons, the treatment of regional organ ischemia generally has not been developed clinically. Thus, there remains a need for a simple and convenient system for delivering oxygenated blood and other fluids to patients for the localized prevention of ischemia and the treatment of post-ischemic tissue and organs.
The present invention may address one or more of the problems set forth above. Certain possible aspects of the present invention are set forth below as examples. It should be understood that these aspects are presented merely to provide the reader with a brief summary of certain forms the invention might take and that these aspects are not intended to limit the scope of the invention. Indeed, the invention may encompass a variety of aspects that may not be set forth below.
In one embodiment of the present invention, a system for the preparation and delivery of oxygenated blood is provided. In applications involving the prevention of ischemia or the treatment of ischemic tissues, the system may be used for the preparation and delivery of oxygenated blood to a specific location within a patient""s body. The system may include an extracorporeal circuit for oxygenating blood, e.g., increasing the level of oxygen in the blood, in which the blood to be oxygenated is blood withdrawn from the patient. The system also may be used advantageously for regional or localized delivery of oxygenated blood.
Factors influencing the determination of blood flow characteristics for the extracorporeal circuit may include one or more of the many clinical parameters or variables of the oxygenated blood to be supplied to the patient, e.g., the size of the patient, the percentage of overall circulation to be provided, the size of the target to be accessed, hemolysis, hemodilution, pO2, pulsatility, mass flow rate, volume flow rate, temperature, hemoglobin concentration and pH.
The system may comprise a delivery assembly including an elongated, generally tubular assembly including a central lumen and at least one end placeable within a patient body proximate a tissue site to be treated, the end including an outlet port for the oxygenated blood. The delivery assembly advantageously comprises a catheter defining a fluid pathway, including a proximal portion adapted for coupling to an oxygenated blood supply assembly, and a distal portion defining a fluid pathway removably insertable within a patient""s body, for infusing the oxygenated blood to predetermined sites. Alternatively, the delivery assembly may comprise an infusion guidewire, sheath, or other similar interventional device of the type used to deliver fluids to patients.
The embodiments may be used in conjunction with angiographic or guiding catheters, arterial sheaths, and/or other devices used in angioplasty and in other interventional cardiovascular procedures. The system may be used in applications involving one or more vascular openings, i.e., in either contralateral or ipsilateral procedures.
In contralateral procedures blood is withdrawn from the patient at a first location, e.g., the left femoral artery. The oxygenated blood is returned to the patient at a second location proximate the tissue to be treated. Blood oxygenation occurs as the blood pumped through the extracorporeal circuit or loop passes through an oxygenation assembly and forms the oxygenated blood to be delivered. In applications where the system includes a catheter, the catheter may include a distal end removably insertable within a patient""s body through a second location, such as the patient""s right femoral artery. The distal end includes at least one port in fluid communication with the central lumen and through which the oxygenated blood may exit. Further, the distal portion of the catheter may be adapted with a tip portion shaped so as to promote insertion of the device, such as through the same sheath used for interventional procedures like angioplasty, to specific predetermined locations within a patient""s body. Examples of tip portion shapes which may be used include any of the standard clinically accepted tip configurations used with devices like guide catheters for providing access to and for holding in locations like the coronary ostium. Accordingly, the method may further include the step of positioning the portion of the distal end of the catheter including the fluid exit port at a predetermined location within a patient body proximate to the tissue to be treated.
In ipsilateral procedures, the system may be used along with one or more of any of a number of suitable, standard-size, clinically accepted guide catheters and/or introducer sheaths. The system, for example, may comprise a catheter, a catheter and guide catheter, or a catheter and sheath, for use within a guide catheter or introducer sheath used for the primary interventional procedure.
The delivery assembly advantageously comprises a catheter suitable for sub-selective delivery of the oxygenated blood. However, the catheter embodiment selected for use will depend upon the circumstances involved in a particular application. For example, in some cases involving the prevention of myocardial ischemia or the treatment of ischemic myocardial tissues, a selective or non-selective catheter may be preferred.
The delivery of oxygenated blood may occur via a xe2x80x9csimplexe2x80x9d interventional device (e.g., a catheter or infusion guidewire) or a delivery device or lumen associated with or forming a part of a multiple-component assembly operable for the performance of diagnostic and/or therapeutic procedures (i.e., in addition to the delivery of oxygenated blood). Examples of such assemblies include, without limitation, devices for the placement of stents, angioplasty balloon catheters, radiation delivery systems, drug delivery devices, etc. Flow rates of about 25 ml/min to about 200 ml/min for the oxygenated blood may be advantageous, particularly about 75 ml/min to about 125 ml/min.
Advantageously, oxygenated blood is provided to a particular desired location by a fluid delivery apparatus including: (1) a generally elongated fluid delivery assembly having a proximal section and a distal section, the distal section including a portion at least partially removably insertable within a patient""s body, the removably insertable portion including at least one fluid exit port in fluid communication with a fluid delivery lumen extending between the proximal section and the removably insertable portion of the fluid delivery assembly; and (2) a fluid conduit having: a first end portion for receiving a supply of blood at the outlet of a blood pump operably coupled to the fluid conduit; a second end releasably coupled to the fluid delivery lumen of the fluid delivery assembly; and an intermediate portion between the first and second ends adapted for oxygenating the supply of blood; the fluid conduit and the fluid delivery lumen defining a continuous fluid pathway between the first end portion of the fluid conduit and the fluid exit port(s). Advantageously, the fluid delivery apparatus provides oxygenated blood, and most advantageously hyperoxemic or hyperbaric blood, to a patient without potentially clinically significant gas bubbles in the blood. More advantageously, the fluid delivery apparatus can provide to a patient oxygenated blood having a pO2 greater than about 760 mm Hg but less than pO2max for a given blood flow rate Qblood, where pO2max equals the maximum back pressure generated within the fluid delivery apparatus by operation of the blood pump to achieve the flow rate Qblood.
In one embodiment, the intermediate portion of the fluid conduit adapted for oxygenating the blood supplied by the blood pump, i.e., the oxygenation assembly, comprises a high pressure membrane oxygenator. In another embodiment, the fluid conduit intermediate portion comprises an assembly including a mixing region in which an oxygenated fluid, e.g., an oxygen-supersaturated fluid, combines with the blood to effect direct liquid-to-liquid oxygenation. In a further embodiment, the intermediate portion may comprise an assembly for combining two fluid streams (e.g., an apparatus generally resembling a y-tube, t-adaptor, or the like), the assembly adapted for coupling to delivery systems for supplying blood to be oxygenated and for supplying oxygenated blood or other fluids.
Accordingly, the fluid delivery apparatus advantageously may comprise a first tube portion extending between a blood pump and an oxygenation assembly; the oxygenation assembly; a second tube portion extending between the oxygenation assembly and the proximal end of a fluid delivery assembly; and the fluid delivery assembly.
In a patient breathing air through the lungs, the dissolved gases in the patient""s blood (nitrogen, N2; carbon dioxide, CO2; and oxygen, O2) equal atmospheric pressure. Chemically, this relationship is noted by the equation
Ptotal=pN2+pCO2+pO2
where Ptotal is atmospheric pressure and the right-hand side of the equation shows the relative, or partial, pressures of the dissolved gases in air. The above equation is balanced approximately as follows:
760 mm Hg=600 mm Hg+45 mm Hg+115 mm Hg
For blood including dissolved gases having the partial pressures put forth above, during a hyperoxygenation process occurring at the intermediate portion of the fluid conduit the pO2 is raised and Ptotal can exceed atmospheric pressure. For example, if the pO2 increases to 800 mm Hg without change to pN2 and pCO2, then Ptotal would equal 1445 mm Hg, a nearly two-fold increase.
The fluid pressure at the outlet of the intermediate portion of the fluid conduit, Pfluid, is a measure of the pressure differential across the portion of the fluid conduit between that location and the fluid exit port(s) plus the outlet pressure. To avoid the formation of potentially clinically significant gas bubbles, it is particularly advantageous to raise the fluid pressure at the outlet of the intermediate portion of the fluid conduit to a level that exceeds the total dissolved gas pressure. Thus, delivery of oxygenated blood may occur bubble-free, i.e., without the formation of potentially clinically significant bubbles, where Pfluid greater than Ptotal.
Because most pressure measurements use gauge pressures (i.e., gauge pressure=total pressure minus atmospheric pressure), the relationship for bubble-free delivery also may be simplified and approximated to xcex94Pfluid greater than pO2(out), where pO2(out) is the pO2 of the oxygenated blood to be delivered to the patient. In other words, a caregiver might need only compare two simple measurements, xcex94Pfluid and pO2(out), to ensure bubble-free delivery during a procedure.
Experimental data supports use of the simplified and approximated relationship xcex94Pfluid greater than pO2(out) for achieving bubble-free delivery. As shown in Table I, a fluid delivery apparatus including a liquid-to-liquid oxygenation assembly was used with two catheters having different effective diameters to infuse oxygenated blood into the left coronary vasculature of a 40 kg swine to determine whether the relationship between xcex94Pfluid and pO2(out) affects bubble formation during oxygenated blood infusion. In trials where xcex94Pfluid greater than pO2(out), no bubbles were observed using 2D-echocardiography during oxygenated blood infusion, and an ultrasonic bubble detection system did not detect any bubbles of greater than about 100 xcexcm diameter. On the other hand, in trials where xcex94Pfluid less than pO2(out), 3-4 bubbles per heart beat were observed in the right atrium using 2D-echocardiography during oxygenated blood infusion, and the ultrasonic bubble detection system detected numerous bubbles of greater than about 100 xcexcm diameter.
Typically, pO2(out) may be selected by the caregiver based upon the circumstances involved in a particular application. Thus, bubble-free delivery may be ensured by selecting an appropriate fluid delivery apparatus, i.e., one which may effect downstream of the fluid conduit intermediate portion a fluid pressure drop that exceeds the selected target pO2 for a given blood flow rate. Further, the fluid pressure drop may vary depending upon factors such as fluid delivery length and fluid lumen geometry (e.g., internal diameter, taper, cross-sectional profile, etc.), factors which may vary depending upon the specific application involved. Thus, it may prove helpful (e.g., to promote ease of selection) to characterize all or a portion of the fluid delivery apparatus downstream of the intermediate portion of the fluid conduit in terms of an effective diameter, or in terms of achievable pO2 levels for a given oxygenation assembly and/or given conditions at the outlet of the intermediate portion of the fluid conduit.
For example, in accordance with one embodiment of the present invention, for an exemplary oxygenated blood fluid delivery apparatus, oxygenated blood pressure at the oxygenation assembly is a function of blood flow rate and catheter effective diameter. For an oxygenated blood fluid delivery apparatus, the relationship between blood flow rate and oxygenated blood pressure at the oxygenation assembly for a given catheter may be determined using the Hagen-Poiseuille law: Q = πΔ xe2x80x83 PD 4 128 xe2x80x83 L xe2x80x83 η
which generally governs laminar fluid flows through conduits, in which Q=volumetric flow rate; L=conduit length; D=conduit inside diameter; xcex7=fluid viscosity; and xcex94P=pressure difference across the conduit length. Other embodiments also may be used depending upon the circumstances involved in a particular application, e.g., an embodiment for turbulent flow applications, for which the relationship between blood flow rate and oxygenated blood pressure at the oxygenation assembly may be determined using models governing turbulent flow.
In general, with a given oxygenated blood fluid delivery apparatus, for a constant blood flow rate Qblood, as the effective inner diameter of the catheter increases, the blood pressure Pfluid(gauge) at the oxygenation assembly decreases. By knowing the simplified and approximated bubble-free delivery relationship, xcex94Pfluid greater than pO2(out), a caregiver having a catheter characterized by effective inner diameter may determine whether an appropriate range of blood flow rates are achievable if the caregiver were to use a fluid delivery apparatus including the catheter to deliver blood having a desired pO2. Alternatively, a caregiver specifying a desired oxygenated blood pO2 and oxygenated blood flow rate range may select a catheter for use in a fluid delivery apparatus for a particular application.
In one embodiment, the system provided advantageously includes a membrane oxygenator assembly and assemblies for supplying controlled flows or supplies of oxygen gas and blood. Advantageously, the intermediate portion of the fluid conduit comprises a membrane oxygenator assembly operable at high pressures, i.e., oxygen gas and blood supply pressures within the membrane oxygenator assembly of greater than atmospheric pressure.
The assembly for supplying controlled flows or supplies of oxygen gas advantageously includes a regulated source of oxygen gas, so that oxygen gas is delivered to the membrane oxygenator assembly at a pressure greater than atmospheric pressure. Advantageously, oxygen gas is supplied to the membrane oxygenator assembly at a pressure greater than atmospheric pressure and less than about 50 p.s.i.a., the approximate maximum pressure that may be generated by commercially available blood pumps delivering blood. The assembly for supplying controlled flows or supplies of oxygen gas may be one of the many commercially available and clinically accepted oxygen delivery systems suitable for use with human patients (e.g., regulated bottled oxygen).
The assembly for supplying controlled flows or supplies of blood advantageously includes a source of blood in combination with means for providing the blood to the membrane oxygenator assembly. Advantageously, the blood to be oxygenated comprises blood withdrawn from the patient, so that the blood supply assembly includes a blood inlet disposed along a portion of a catheter or other similar device at least partially removably insertable within the patient""s body; a pump loop that in combination with the catheter or other device defines a continuous fluid pathway between the blood inlet and the membrane oxygenator assembly; and a blood pump for controlling the flow of blood through the pump loop, i.e., the flow of blood provided to the membrane oxygenator assembly. The blood pump may be one of the many commercially available and clinically accepted blood pumps suitable for use with human patients. One example of such a pump is the Model 6501 RFL3.5 Pemco peristaltic pump available from Pemco Medical, Cleveland, Ohio.
The system provided advantageously includes an oxygenated blood supply assembly comprising a membrane oxygenator assembly including at least one membrane separating within the membrane oxygenator assembly the oxygen gas provided by the oxygen gas supply assembly and the blood provided by the blood supply assembly, and across which oxygen and other gases may diffuse. Advantageously, oxygen gas is provided to the xe2x80x9cgas sidexe2x80x9d of the membrane oxygenator assembly by the oxygen gas supply assembly at a gas side pressure that is greater than atmospheric pressure; a supply of blood is provided by the blood supply assembly to the xe2x80x9cblood sidexe2x80x9d of the membrane oxygenator assembly at a blood side pressure that is greater than the gas side pressure; and the oxygen gas and at least a portion of the supply of blood is maintained in contact with the membrane so that oxygen diffuses across the membrane and dissolves in the supply of blood.
The membrane may comprise either a solid material (e.g., silicone rubber) or a microporous material (e.g., a polymeric material, such as polypropylene). Advantageously, the blood side pressure is maintained at a higher level than the gas side pressure to prevent bulk gas flow across the membrane. However, lower blood side pressures may be used if a solid, non-porous membrane is used. The type of membrane used, and the gas and blood side pressures (which may be defined, for example, by a given pressure differential across the membrane) may vary depending upon the circumstances involved in a particular desired application.
The gas side of the membrane oxygenator assembly may be operated in either an xe2x80x9copenxe2x80x9d or a xe2x80x9cclosedxe2x80x9d mode. In open mode, a gas side stream including oxygen gas provided by the oxygen gas supply assembly xe2x80x9csweepsxe2x80x9d through the gas side of the membrane oxygenator assembly. During the sweep oxygen diffuses across the membrane to dissolve in the blood, and blood gases such as carbon dioxide and nitrogen may diffuse across the membrane to join the gas side stream. The gas side stream exits the membrane oxygenator assembly via a vent or other fluid exit conduit. In closed mode, the vent or other fluid exit conduit is closed so as to prevent the escape of bulk gas from the gas side of the membrane oxygenator assembly.
In an alternate embodiment, the membrane oxygenator assembly includes a gas inlet but is not adapted with a vent or other gas side stream fluid exit conduit. This alternate embodiment thus comprises a closed mode device. In closed mode operation the gas side pressure advantageously equals the pressure at which the oxygen gas supply assembly provides oxygen gas to the membrane oxygenator assembly. In open mode the gas side pressure drops through the membrane oxygenator assembly, albeit perhaps only slightly, from the pressure at which the oxygen gas supply assembly provides oxygen gas to the membrane oxygenator assembly.
The membrane oxygenator assembly advantageously is sized depending upon the circumstances involved in a particular desired application. For example, for an oxygenated blood delivery flow less than 0.3 liters per minute, an active membrane surface area of much less than two square meters (the approximate active membrane surface area for a conventional adult size oxygenator capable of handling six liters of blood per minute) is required. By way of example only, and without limitation on the scope of the present invention, factors affecting membrane oxygenator assembly sizing include the desired oxygen level for the blood to be oxygenated and oxygenated blood flow rate.
The system provided advantageously delivers oxygenated blood from the membrane oxygenator assembly to a given site without the formation or release of clinically significant oxygen bubbles. Delivery of oxygenated blood at a given site without clinically significant bubble formation or release advantageously may be accomplished through the selection of a catheter material, the use of an appropriately sized delivery catheter, and/or the conditioning of the same to eliminate nucleation sites. The exact material, size and conditioning procedure may vary depending upon the circumstances involved in a particular application. By way of example only, and without limitation as to the scope of the present invention, for the delivery of about 3 ml/sec of oxygenated blood with a membrane oxygenator assembly operating with a gas side pressure of about 50 p.s.i., a catheter having a length of about 130 cm and inside diameter of about 40 mils would provide a gradual pressure reduction which may help prevent the release of potentially clinically significant gas bubbles.
In another embodiment, a method is provided for the preparation and delivery of oxygenated blood. A method for enriching blood with oxygen is provided comprising providing a membrane having first and second sides; providing in contact with the first side of the membrane oxygen gas at a pressure P1 that is greater than atmospheric pressure; providing on the second side of the membrane a supply of blood at a pressure P2 that is greater than P1; and maintaining at least a portion of the supply of blood in contact with the second side of the membrane so that oxygen diffuses across the membrane and dissolves in the supply of blood. Advantageously, the pressure P1 is greater than atmospheric pressure and less than about 50 p.s.i.a. The method advantageously further comprises providing in contact with the first side of the membrane a stream including oxygen gas. Advantageously, the stream maintains contact with the first side of the membrane so that a gas (e.g., carbon dioxide, nitrogen, water vapor, etc.) in the supply of blood diffuses across the membrane and joins the stream.
In accordance with another embodiment, a method is provided for delivering oxygenated blood to a specific site within a patient""s body. The method comprises raising the pO2 level of blood to be supplied to the patient and the delivery of such blood to a given site. The method may include the step of controlling or providing controlled amounts of blood and oxygen gas to a membrane oxygenator assembly so as to produce oxygenated blood for delivery to a specific predetermined site. Blood oxygen levels (e.g., pO2) may be maintained, adjusted, or otherwise controlled by controlling the flow rates or by providing controlled amounts of the blood and/or oxygen gas. Thus, a blood-gas control method is provided.
In another embodiment, the intermediate portion of the fluid conduit adapted for oxygenating the blood supplied by the blood pump comprises an assembly including a mixing region in which an oxygenated fluid, e.g., an oxygen-supersaturated fluid, combines with the blood. Advantageously, the mixing region is defined by a chamber-like assembly including an injection zone in which the oxygenated fluid mixes with the blood at a higher pressure than the target pO2 for the blood. Oxygenation of the blood occurs as a result of convective mixing involving the two contacting fluids and to a lesser extent as a result of oxygen diffusing directly from the oxygenated liquid to the blood, i.e., dispersion. The mixing advantageously is a convective mixing that occurs rapidly and completely.
In one embodiment, the chamber-like assembly comprises a mixing chamber including a generally elongated cylindrically-shaped or tubular assembly having upper and lower ends, each end having a cap or similar device fixedly attached thereto, so as to define an interior space therein. Advantageously, the mixing chamber includes in fluid communication with the interior space a first inlet port adapted for receiving a supply of blood to be oxygenated; a second inlet port adapted for receiving a supply of oxygenated fluid to be mixed with the blood; and an exit port adapted for delivery of the oxygenated blood to a particular desired location.
To promote mixing of the blood and oxygenated fluid within the chamber interior space, the blood to be oxygenated advantageously enters the mixing chamber from a location and in a direction so that a vortical or cyclonic flow of blood is created within the chamber. Advantageously, the blood enters the chamber along a path substantially tangential to the chamber wall. Advantageously, the oxygenated liquid enters the chamber proximate the blood inlet, and the oxygenated blood exits the chamber through a port in the bottom of the chamber. More advantageously, the oxygenated liquid enters the chamber in a generally upward direction normal to the initial direction of travel of the blood entering the chamber.
The mixing chamber advantageously is pressurizeable, with the lower portion of the chamber accumulating a supply of blood and the upper portion including a gas head. The gas head advantageously helps dampen the pulsatility of the blood entering the chamber.
The oxygenated fluid advantageously comprises an oxygen-supersaturated fluid in which the dissolved oxygen content would occupy a volume of between about 0.5 and about 3 times the volume of the solvent normalized to standard temperature and pressure. Examples of solvents which may be used include saline, lactated Ringer""s, and other aqueous physiologic solutions. The oxygenated fluid advantageously is delivered to the mixing chamber via one or more capillaries having an internal diameter in the range of about 15 to about 700 xcexcm (advantageously, about 100 xcexcm), the capillaries forming a continuous fluid flow pathway between the mixing chamber and a supply or an assembly for providing a supply of the oxygenated fluid.
The oxygenated fluid typically will be supplied to the mixing chamber in accordance with parameters specified and selected by the caregiver for the desired clinical indication. The flow of oxygenated fluid is generally steady and continuous, although variable or intermittent flows may be used. Flow rates may range from about 0.1 cc/min to about 40 cc/mm, although particularly advantageous flow rates may be between about 2 cc/min and 12 cc/min. Oxygen concentrations normalized to standard temperature and pressure may range from about 0.1 ml O2 per ml physiologic solution to about 3 ml O2 per ml physiologic solution, although particularly advantageous concentrations may be about 1 ml O2 per ml physiologic solution.
In another embodiment, a method is provided for the preparation and delivery of oxygenated blood. The method comprises providing a chamber assembly in which blood and an oxygenated liquid, e.g., an oxygen-supersaturated liquid, mix under pressure to form oxygenated blood. The method may include the step of controlling or providing controlled amounts of blood and oxygenated liquid to the chamber assembly to maintain, adjust or otherwise control blood oxygen levels. Thus, an alternate embodiment blood-gas control method is provided.
The oxygenated blood advantageously is provided to the patient at about 37xc2x0 C., i.e., system operation does not significantly affect patient blood temperature. However, in some instances, cooling of the oxygenated blood may be desired, e.g., to induce local or regional hypothermia (e.g., temperatures below about 35xc2x0 C.). By way of example only, in neurological applications such cooling may be desired to achieve a neuroprotective effect. Hypothermia also may be regarded as an advantageous treatment or preservation technique for ischemic organs, organ donations, or reducing metabolic demand during periods of reduced perfusion.
Accordingly, the system provided may include a heat exchanger assembly operable to maintain, to increase, or to decrease the temperature of the oxygenated blood as desired in view of the circumstances involved in a particular application. Advantageously, temperatures for the oxygenated blood in the range of about 35xc2x0 C. to about 37xc2x0 C. generally will be desired, although blood temperatures outside that range (e.g., perhaps as low as 29xc2x0 C. or more) may be more advantageous provided that patient core temperature remains at safe levels in view of the circumstances involved in the particular application. Temperature monitoring may occur, e.g., with one or more thermocouples, thermistors or temperature sensors integrated into the electronic circuitry of a feedback controlled system, so that an operator may input a desired perfusate temperature with an expected system response time of seconds or minutes depending upon infusion flow rates and other parameters associated with the active infusion of cooled oxygenated blood.
Examples of heat exchange assemblies suitable for use with the present system, either alone or integrated with a system component, include any of the numerous commercially available and clinically accepted heat exchanger systems used in blood delivery systems today, e.g., heat exchangers, heat radiating devices, convective cooling devices and closed refrigerant devices. Such devices may include, e.g., conductive/convective heat exchange tubes, made typically of stainless steel or high strength polymers, in contact with blood on one side and with a coolant on the other side.
In another embodiment, in a liquid-to-liquid oxygenation assembly, cooled oxygenated blood is provided by mixing blood with a cooled oxygenated liquid, e.g., an oxygen-supersaturated liquid. Any commercially available and clinically acceptable heat exchange system may be used to cool the oxygenated liquid and/or cool the oxygenated blood. Because most gases show increased solubility when dissolved into aqueous liquids at low temperatures (e.g., oxygen solubility in water increases at a rate of 1.3% per degree Celsius decrease) such a method offers the added benefit of enhanced stability of the oxygenated blood, which in some cases may enable increased oxygen concentrations.
The system may include one or more gas bubble detectors, at least one of which is capable of detecting the presence of microbubbles, e.g., bubbles with diameters of about 100 xcexcm to about 1000 xcexcm. In addition, the system may include one or more macrobubble detectors to detect larger bubbles, such as bubbles with diameters of about 1000 xcexcm or more. Such macrobubble detectors may comprise any suitable commercially available detector, such as an outside, tube-mounted bubble detector including two transducers measuring attenuation of a sound pulse traveling from one side of the tube to the other. One such suitable detector may be purchased from Transonic Inc. of New York.
The microbubble and macrobubble detectors provide the physician or caregiver with a warning of potential clinically significant bubble generation. Such warnings also may be obtained through the use of transthoracic 2-D echo (e.g., to look for echo brightening of myocardial tissue) and the monitoring of other patient data.
Advantageously, the bubble detection system is able to discriminate between various size bubbles. Further, the bubble detection system advantageously operates continuously and is operatively coupled to the overall system so that an overall system shutdown occurs upon the sensing of a macrobubble.
The system also may include various conventional items, such as sensors, flow meters (which also may serve a dual role as a macrobubble detector), or other clinical parameter monitoring devices; hydraulic components such as accumulators and valves for managing flow dynamics; access ports which permit withdrawal of fluids; filters or other safety devices to help ensure sterility; or other devices that generally may assist in controlling the flow of one or more of the fluids in the system. Advantageously, any such devices are positioned within the system and used so as to avoid causing the formation of clinically significant bubbles within the fluid flow paths, and/or to prevent fluid flow disruptions, e.g., blockages of capillaries or other fluid pathways. Further, the system advantageously comprises a biocompatible system acceptable for clinical use with human patients. | {
"pile_set_name": "USPTO Backgrounds"
} |
The present invention is directed to aminoglycoside compounds and in particular to aryl substituted aminoglycosides and synthetic methods for their preparation and use as therapeutic or prophylactic agents.
A particular interest in modem drug discovery is the development of novel low molecular weight orally-bioavailable drugs that work by binding to RNA. RNA, which serves as a messenger between DNA and proteins, was thought to be an entirely flexible molecule without significant structural complexity. Recent studies have revealed a surprising intricacy in RNA structure. RNA has a structural complexity rivaling proteins, rather than simple motifs like DNA. Genome sequencing reveals both the sequences of the proteins and the mRNAs that encode them. Since proteins are synthesized using an RNA template, such proteins can be inhibited by preventing their production in the first place by interfering with the translation of the mRNA. Since both proteins and the RNAs are potential drug targeting sites, the number of targets revealed from genome sequencing efforts is effectively doubled. These observations unlock a new world of opportunities for the pharmaceutical industry to target RNA with small molecules.
Classical drug discovery has focused on proteins as targets for intervention. Proteins can be extremely difficult to isolate and purify in the appropriate form for use in assays for drug screening. Many proteins require post-translational modifications that occur only in specific cell types under specific conditions. Proteins fold into globular domains with hydrophobic cores and hydrophilic and charged groups on the surface. Multiple subunits frequently form complexes, which may be required for a valid drug screen. Membrane proteins usually need to be embedded in a membrane to retain their proper shape. The smallest practical unit of a protein that can be used in drug screening is a globular domain. The notion of removing a single alpha helix or turn of a beta sheet and using it in a drug screen is not practical, since only the intact protein may have the appropriate 3-dimensional shape for drug binding. Preparation of biologically active proteins for screening is a major limitation of classical high throughput screening and obtaining biologically active forms of proteins is an expensive and limiting reagent in high throughput screening efforts.
For screening to discover compounds that bind RNA targets, the classic approaches used for proteins can be superceded with new approaches. All RNAs are essentially equivalent in their solubility, ease of synthesis or use in assays. The physical properties of RNAs are independent of the protein they encode. They may be readily prepared in large quantity through either chemical or enzymatic synthesis and are not extensively modified in vivo. With RNA, the smallest practical unit for drug binding is the functional subdomain. A functional subdomain in RNA is a fragment that, when removed from the larger RNA and studied in isolation, retains its biologically relevant shape and protein or RNA-binding properties. The size and composition RNA functional subdomains make them accessible by enzymatic or chemical synthesis. The structural biology community has developed significant experience in identification of functional RNA subdomains in order to facilitate structural studies by techniques such as NMR spectroscopy. For example, small analogs of the decoding region of 16S rRNA (the A-site) have been identified as containing only the essential region, and have been shown to bind antibiotics in the same fashion as the intact ribosome.
The binding sites on RNA are hydrophilic and relatively open as compared to proteins. The potential for small molecule recognition based on shape is enhanced by the deformability of RNA. The binding of molecules to specific RNA targets can be determined by global conformation and the distribution of charged, aromatic, and hydrogen bonding groups off of a relatively rigid scaffold. Properly placed positive charge are beleived to be important, since long-range electrostatic interactions can be used to steer molecules into a binding pocket with the proper orientation. In structures where nucleobases are exposed, stacking interactions with aromatic functional groups may contribute to the binding interaction. The major groove of RNA provides many sites for specific hydrogen bonding with a ligand. These include the aromatic N7 nitrogen atoms of adenosine and guanosine, the O4 and O6 oxygen atoms of uridine and guanosine, and the amines of adenosine and cytidine. The rich structural and sequence diversity of RNA suggests to us that ligands can be created with high affinity and specificity for their target.
Although our understanding of RNA structure and folding, as well as the modes in which RNA is recognized by other ligands, is far from being comprehensive, significant progress has been made in the last decade (Chow, C. S.; Bogdan, F. M., Chem. Rev., 1997, 97, 1489, Wallis, M. G.; Schroeder, R., Prog. Biophys. Molec. Biol. 1997, 67, 141). Despite the central role RNA plays in the replication of bacteria, drugs that target these pivotal RNA sites of these pathogens are scarce. The increasing problem of bacterial resistance to antibiotics make the search for novel RNA binders of crucial importance.
Certain small molecules can bind RNA and block essential functions of the 20 bound RNA. Examples of such molecules include erythromycin, which binds to bacterial rRNA and releases peptidyl-tRNA and mRNA, and the aminoglycoside antibiotics. Aminoglycoside antibiotics have long been known to bind RNA. They exert their antibacterial effects by binding to specific target sites in the bacterial ribosome. For the structurally related antibiotics neamine, ribostamycin, neomycin B, and paromomycin, the binding site has been localized to the A-site of the prokaryotic 16S ribosomal decoding region RNA (Moazed, D.; Noller, H. F., Nature, 1987, 327, 389). Binding of aminoglycosides to this RNA target interferes with the fidelity of mRNA translation and results in miscoding and truncation, leading ultimately to bacterial cell death (Alper, P. B.; Hendrix, M.; Sears, P.; Wong, C., J. Am. Chem. Soc., 1998, 120, 1965).
There is a need in the art for new chemical entities that work against bacteria with broad-spectrum activity. Perhaps the biggest challenge in discovering RNA-binding antibacterial drugs is identifying vital structures common to bacteria that can be disabled by small molecule drug binding. A challenge in targeting RNA with small molecules is to develop a chemical strategy which recognizes specific shapes of RNA. There are three sets of data that provide hints on how to do this: natural protein interactions with RNA, natural product antibiotics that bind RNA, and man-made RNAs (aptamers) that bind small molecules. Each data set, however, provides different insights to the problem.
Several classes of drugs obtained from natural sources have been shown to work by binding to RNA or RNA/protein complexes. These include three different structural classes of antibiotics: thiostreptone, the aminoglycoside family and the macrolide family of antibiotics. These examples provide powerful clues to how small molecules and targets might be selected. Nature has selected RNA targets in the ribosome, one of the most ancient and conserved targets in bacteria. Since antibacterial drugs are desired to be potent and have broad-spectrum activity these ancient processes fundamental to all bacterial life represent attractive targets. The closer we get to ancient conserved functions the more likely we are to find broadly conserved RNA shapes. It is important to also consider the shape of the equivalent structure in humans, since bacteria were unlikely to have considered the therapeutic index of their RNAs while evolving them.
A large number of natural antibiotics exist, these include the aminoglycosides, kirromycin, neomycin, paromomycin, thiostrepton, and many others. They are very potent, bactericidal compounds that bind RNA of the small ribosomal subunit. The bactericidal action is mediated by binding to the bacterial RNA in a fashion that leads to misreading of the genetic code. Misreading of the code while translating integral membrane proteins is thought to produce abnormal proteins that compromise the barrier properties of the bacterial membrane.
Antibiotics are chemical substances produced by various species of microorganisms (bacteria, fungi, actinomycetes) that suppress the growth of other microorganisms and may eventually destroy them. However, common usage often extends the term antibiotics to include synthetic antibacterial agents, such as the sulfonamides, and quinolines, that are not products of microbes. The number of antibiotics that have been identified now extends into the hundreds, and many of these have been developed to the stage where they are of value in the therapy of infectious diseases. Antibiotics differ markedly in physical, chemical, and pharmacological properties, antibacterial spectra, and mechanisms of action. In recent years, knowledge of molecular mechanisms of bacterial, fungal, and viral replication has greatly facilitated rational development of compounds that can interfere with the life cycles of these microorganisms.
At least 30% of all hospitalized patients now receive one or more courses of therapy with antibiotics, and millions of potentially fatal infections have been cured. At the same time, these pharmaceutical agents have become among the most misused of those available to the practicing physician. One result of widespread use of antimicrobial agents has been the emergence of antibiotic-resistant pathogens, which in turn has created an ever-increasing need for new drugs. Many of these agents have also contributed significantly to the rising costs of medical care.
When the antimicrobial activity of a new agent is first tested a pattern of sensitivity and resistance is usually defined. Unfortunately, this spectrum of activity can subsequently change to a remarkable degree, because microorganisms have evolved the array of ingenious alterations discussed above that allow them to survive in the presence of antibiotics. The mechanism of drug resistance varies form microorganism to microorganism and from drug to drug.
The development of resistance to antibiotics usually involves a stable genetic change, heritable from generation to generation. Any of the mechanisms that result in alteration of bacterial genetic composition can operate. While mutation is frequently the cause, resistance to antimicrobial agents may be acquired through transfer of genetic material from one bacterium to another by transduction, transformation or conjugation.
For the foregoing reasons, there is a need for new chemical entities that possess antimicrobial activity. Further, in order to accelerate the drug discovery process, new methods for synthesizing aminoglycoside antibiotics are needed to provide an array of compounds that are potentially new drugs for the treatment microbial infections.
In an aspect of the present invention there are provided compounds of the formula (I):
wherein,
R1 and R2 are independently amino or protected amino;
X is O, S, or NH;
Y is a bond or a divalent linking group;
R3 is aryl, heteroaryl, substituted aryl or substituted heteroaryl; and
one of R4 and R5 is hydroxyl or protected hydroxyl, and the other is selected from the group consisting of formula (II), (III) and (IV):
wherein
R6 and R7 are independently hydroxyl or protected hydroxyl;
R8, R9, R10, and R11 are independently hydroxyl, protected hydroxyl, amino or protected amino;
R12 and R13 are independently H or alkyl; and
Z is O, S or NH. | {
"pile_set_name": "USPTO Backgrounds"
} |
Energy storage components, such as batteries and capacitors, are used in a variety of electronic devices. As technology evolves, devices using these components consistently demand smaller component sizes. However, in meeting the demands of technology, these components cannot sacrifice performance. As such, the art requires energy storage components which are smaller, but which meet or exceed energy requirements.
In meeting these requirements, energy storage components have their own requirements, extending to manufacturing, use, and end of life performance. Manufacturing requirements demand reliable and efficient assembly. Use requirements demand reliability and small package sizes having satisfactory power delivery. End of life requirements require that as the components age, they retain their operable characteristics. Within each of these phases is the demand that battery subcomponents are not damaged by other battery subcomponents. Thus, what is needed are new energy storage subcomponent designs which demonstrate improved properties with respect to manufacturing, use, and end of life, without damaging other subcomponents. | {
"pile_set_name": "USPTO Backgrounds"
} |
Intraluminal devices such as grafts and stents are known for treating stenosis, stricture, aneurysms and the like. These devices may be implanted either transluminally in a minimally invasive procedure or may be surgically implanted.
Such intraluminal devices provide a technique for expanding a constricted vessel or for maintaining an open passageway through a vessel. One common technique used to hold open a blocked or constricted vessel such as a blood vessel is to employ a vascular stent. Stents are implantable intraluminal devices typically formed of wire which may be radially expanded to hold open constricted vessels. Thus, wire stents are useful to prevent restenosis of a dilated vessel or to eliminate the danger of reocclusion of the vessel. In addition, wire stents can also be used to reinforce various lumen in danger of collapse. However, stents are not generally designed as conduits or bypass devices.
Intraluminal or endoprosthetic grafts, however, are designed as bypass devices which allow fluid flow therethrough. Often, these devices are percutaneously implanted within the vascular system to reinforce collapsing, partially occluded, weakened or abnormally dilated localized sections of, e.g., a blood vessel. Grafts may also be surgically implanted by anastomosis to replace a badly damaged portion of vessel.
Vascular grafts may be manufactured from a variety of bio-compatible materials. For example, it is well known to use extruded tubes of polytetrafluoroethylene (PTFE) as vascular grafts. PTFE is particularly suitable as it exhibits superior biocompatibility. PTFE tubes may be used as vascular grafts in the replacement or repair of blood vessels because PTFE exhibits low thrombogenicity. Further, expanded PTFE (ePTFE) tubes have a microporous structure which allows natural tissue ingrowth and cell endothelialization once implanted into the vascular system. This contributes to long term healing and graft patency.
Grafts formed of ePTFE have a fibrous state which is defined by interspaced nodes interconnected by elongated fibrils. The spaces between the node surfaces that are spanned by the fibrils are defined as the internodal distance (IND). The art is replete with examples of vascular grafts made of microporous ePTFE tubes useful as vascular grafts. The porosity of an ePTFE vascular graft is controlled by varying the IND of the microporous structure of the tube. An increase in the IND within a given structure results in enhanced tissue ingrowth, as well as, cell endothelialization along the inner surface thereof. Increasing the porosity of the tubular structure, however, reduces the ability of the graft to retain a suture placed therein during implantation and tends to exhibit low axial tear strength. In order to strike an effective balance between porosity and radial strength, multi-layer ePTFE tubes have been developed. The porosity of these multilayered tubes vary as between the outer and inner layers to achieve a composite structure having sufficient porosity for tissue ingrowth and cell endothelialization while still retaining sufficient radial strength.
It is known in the art to use stents in combination with vascular grafts and other endoprostheses. Stents may be positioned at one or both ends of a graft to support the graft within a portion of the vessel. Thus positioned, the stents help fix the graft to the vessel wall. In addition, stents serve to keep the lumen open and to anchor the graft in place. A single stent may also be employed in combination with a graft to allow the graft to “float” downstream toward the affected vessel. Once properly positioned, the single stent is expanded to anchor the graft in place.
Several techniques for securing one or more stents to a graft are known. For example, hooks or barbs extending from the stent have been used for securing stents to a graft. Alternatively, a stent may be sutured to a graft. Each of these techniques requires either specialized stent attachment means or secondary procedures to secure the stents to the graft.
Traditional stents have various shapes and sizes depending upon their intended function. For example, structures which have previously been used as stents include coiled stainless steel springs, helically wound coiled springs manufactured from an expandable heat-sensitive material, expanding stainless steel stents formed of stainless steel wire in a “zig-zag” pattern, cage-like devices made from malleable metal, and flexible tubes having a plurality of separate expandable ring-like scaffold members which permit radial expansion of a graft. Each of these devices is designed to be radially compressible and expandable so that it will easily pass through a blood vessel in a collapsed state and can be radially expanded to an implantable size after the target area of the vessel has been reached. Radial expansion and contraction of each of these causes associated longitudinal expansion and contraction of the stent.
Such expandable stents may be supported between the layers of a multi-layer tubular graft. The expandable stent would anchor and support the multi-layer tube within the lumen. Upon radial expansion, the stent would hold the graft outwardly against the inner wall of the lumen.
One example of such a graft-stent combination is shown in U.S. Pat. No. 5,123,917 issued to Lee et al. A stent-graft combination shown therein includes a plurality of separate scaffold members (stents) mounted between an inner tube and an outer tube forming the multi-layer graft. In one embodiment of this invention, the scaffold members are free floating within an intermediate pocket formed by the inner and outer tubes. In another embodiment, the scaffold members are adhesively affixed to the outer surface of the inner tube. In yet another embodiment of this invention, the inner and outer tubes are adhered to each other in such a manner that separate pockets are formed in which individual scaffold members are placed within each pocket.
In each of these different embodiments of the '917 patent, radial expansion of the scaffold member causes a change in the longitudinal expanse thereof. Thus, a drawback to the device shown in the '917 patent is that the net length of the scaffold member increases as the graft contracts. Accordingly, this increase in the net length of the scaffold member increases the stress forces on the graft as well as tends to delaminate the layers. Thus, these stress forces increase the likelihood that the inner tube will become separated from the outer tube and/or that the graft will tear upon expansion of the scaffold members.
Accordingly, it would be desirable to provide an improved intraluminal device, in particular, an ePTFE graft-stent composite device with improved radial strength that allows for the deployment of a stent and graft simultaneously with the stent already permanently positioned on the graft such that additional stress is not placed on the graft by the stent upon expansion. | {
"pile_set_name": "USPTO Backgrounds"
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1. Field of the Invention
The invention relates to a device for turning up the tire sidewalls on a tire building drum with devices for shaping a tire carcass, whereby the tire building drum features two lever systems arranged essentially and/or generally symmetrically to the drum center, which lever systems are each connected to a lever supporting body in a pivoted manner, whereby the two lever supporting bodies can be moved in the axial direction of the tire building drum.
2. Discussion of Background Information
In the conventional production of new tires, one production step takes place on a tire building drum, in which the tire carcass at first resting flat is shaped by an expansion process. The actual shaping process of the carcass takes place, e.g., via a middle bellows that expands the central area of the carcass. In this process the two outer sidewalls are subsequently turned up on the shaped carcass and thereby folded about the bead core. This process of turning up the tire sidewalls takes place either with so-called side shaping bellows or with a roller lever system arranged in a rim-shaped manner over the circumference. When side shaping bellows are used, two inflating bellows arranged in the area of the sidewall layers are inflated, which inflating bellows in this manner press the sidewalls onto the shaped carcass. The turning up process with the aid of side shaping bellows can have the disadvantage that these bellows do not act all the way up to the shoulder areas of the green tire, making manual finishing operation necessary. Furthermore, the side shaping bellows are subject to a high wear, making necessary a correspondingly frequent replacement, which is associated with a high expenditure of time.
Turning up sidewalls with the aid of a roller lever system is disclosed, e.g., in DE 199 34 791 C1. With this device the spreading apart of the roller lever system takes place via a pneumatic drive that comprises two separate pneumatic cylinders. The two pneumatic cylinders are acted on separately with compressed air, spreading apart the tire lever system and turning up the sidewalls on the carcass.
A major disadvantage with this principle is that, e.g., due to different frictional effects, the spreading apart of the opposite tire lever systems does not always occur simultaneously or suddenly. The consequence of the two roller lever systems being spread apart at different times is that the sidewalls are not pressed uniformly against the shaped carcass and a defective connection between the two material layers thus occurs, which in turn can lead to tire wastage. | {
"pile_set_name": "USPTO Backgrounds"
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Ellipsometry, as defined by R. A. Azzam and N. M. Bashara in Ellipsometry and Polarized Light, published by North-Holland Physics Publishing, 1987 edition, is an optical technique for the characterization and observation of events at an interface or film between two media and is based on exploiting the polarization transformation that occurs as a beam of polarized light is reflected from or transmitted through the interface or film. Two factors make ellipsometry particularly attractive: (1) its essential non-perturbing character (when the wavelength and intensity of the light beam are properly chosen) hence its suitability for in-situ measurements, and (2) its remarkable sensitivity to minute interfacial effects, such as the formation of a sparsely distributed sub-monolayer of atoms or molecules. The great diversity of situations in nature and man-made systems where interfaces and films play an important role has lead to the application of ellipsometry in a wide spectrum of fields such as physics, chemistry, materials and photographic science, biology, as well as optical, electronic, mechanical, metallurgical and biomedical engineering.
Ellipsometry is sometimes referred to as polarimetry, generalized polarimetry, or complete polarimetry. The latter names are more common especially when interaction with the sample involves transmission of light through the bulk of the sample and the polarization transformation depends on bulk sample properties as well as surface properties and films.
Azzam and Bashara further state in their aforementioned book that ellipsometry can be generally defined as the measurement of the state of polarization of a polarized vector wave. Ellipsometry is generally conducted in order to obtain "information" about an "optical system" that modifies the state of polarization. In a general scheme of ellipsometry, a polarized light-wave is allowed to interact with an optical system under investigation. The interaction changes the state of polarization of the wave. Measurement of the initial and final states of polarization, repeated for an adequate number of different initial states, leads to the determination of the law of transformation of polarization by the system as described, for example, by its Jones or Mueller matrix. To extract more fundamental information about the optical system than is conveyed by its Jones or Mueller matrix, it is necessary to examine light-matter interaction within the system by the electromagnetic theory of light. In other words, it is necessary to study the details of the internal polarization-modifying processes that are responsible for the external behavior as described by the measured Jones or Mueller matrix of the system.
An operational diagram of a general ellipsometer arrangement as shown in Ellipsometry and Polarized Light is shown in FIG. 1 of the drawings. A beam from a suitable light source (L) is passed through a variable polarizer (P) to produce light of known polarization. This light interacts with the optical system (S) under study and its polarization is modified. The modified state of polarization at the output of the system is measured (analyzed) by a polarization analyzer (A) followed by a photodetector (D). If the light interaction with the sample under study varies with wavelength, a monochromatic light source must be used or a means of isolating quasimonochromatic portions (with known wavelengths) of the light must be provided.
One way in which the light wave can interact with the optical system is by being reflected from a surface of the optical system (S). This reflection causes the state of polarization to be changed abruptly. Such a change can be explained using the Fresnel reflection coefficients for the two linear polarizations parallel (p) and perpendicular (s) to the plane of incidence. Another way the light wave can interact with the optical system is transmission through the material of the optical system. When the polarization state change depends on the angle of interaction of the light beam and the sample under study, as for example with reflection from (or oblique transmission through) a sample, the incident light should be as collimated as possible so only a single angle of incidence is measured at one time.
Azzam and Bashara explain that, since the time of Drude, reflection ellipsometry has been recognized as an important tool for the study of surfaces and thin films. Among the many useful applications of ellipsometry are: (1) measurement of the optical properties of materials and their frequency dependence (wavelength dispersion), the materials may be in the liquid or solid phase, may be optically isotropic or anisotropic, and can be either in bulk or thin-film form; (2) monitoring of phenomena on surfaces that involve either the growth of thin films starting from a submonolayer (e.g., by oxidation, deposition, adsorption or diffusion of impurities), or the removal of such films (e.g., by desorption, sputtering or diffusion); and (3) measurement of physical factors that affect the optical properties such as electric and magnetic fields, stress or temperature.
A description of the principles of ellipsometry, and a discussion of the reflection process, the measurement process, and data reduction can be found in "Ellipsometry A Century Old New Technique" by Dr. Richard F. Spanier, Industrial Research, September 1975, which article is incorporated herein by reference. A diagram of a conventional ellipsometer from Dr. Spanier's article is shown in FIG. 2B. Many additional types of automated and manually operated ellipsometers are known in the art. Dr. Spanier states in the article that ellipsometry involves the measurement of tan .psi., the change in the amplitude ratio upon reflection, and .DELTA., the change in the phase difference upon reflection. The quantities .DELTA. and .psi. are functions of the optical constants of the surface, the wavelength of the light used, the angle of incidence, the optical constants of the ambient medium, and for film-covered surfaces, the thicknesses and optical constants of the films.
Thus, in order to be able to compute the information about a sample's properties which cause a polarization state change in the reflected light, it is necessary to convert the polarization state change together with the angle of incidence and wavelength into physical properties of the sample according to some mathematical model. Properties such as refractive index, thickness, and absorption index of films on a surface or the optical constants of bare surfaces can be computed, for example. Similarly, in the case of transmitted light, properties such as the birefringence of the bulk material can be computed. Each ellipsometric measurement of polarization state change yields one value for .DELTA. and one value for .psi.. Thus, at best, two of the properties of the surface (whether or not film covered) or two properties of the bulk (in the case of transmitted light) can be computed if values for the remaining properties are known from other sources.
Frequently, in the art, one can compute more of these properties, of film covered surfaces, for example, if one has values for .DELTA. and values for .psi., at more than one angle of incidence; preferably, at many angles of incidence. Theoretically, one property can be computed for each independent .DELTA. and one property can be computed for each independent .psi. measured but it is better to overdetermine the unknowns with extra values of .DELTA. and .psi.. Accordingly, it is advantageous to measure as many angles of incidence on a particular sample as possible. However, this has not been done frequently in the past because it is so cumbersome to get the data by making separate successive measurements at each angle through the use of a scanning technique.
It has also been proposed to provide ellipsometers with a plurality of duplicate setups with multiple beams all of different, discrete angles in order to simultaneously obtain information for light at different angles of incidence. These ellipsometers essentially combine several ellipsometers of the known type and use them simultaneously. This technique is limited in the number of angles that can be simultaneously measured because of the need for a plurality of ellipsometers, which can add considerably to the initial cost and maintenance of such a system.
The following U.S. patents are cited of interest for their disclosures relating to ellipsometry and ellipsometers.
______________________________________ 4,030,836 4,077,720 4,052,666 4,434,025 4,053,232 4,472,633 4,516,855 4,725,145 4,585,348 4,834,539 4,647,207 4,837,603 4,653,924 4,850,711 4,655,595 4,866,264 ______________________________________ | {
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Target designators, usually employing lasers, have in the past made use of a so-called “doublet pulse”, a pulse burst containing two pulses, in which the inter-pulse spacing is varied to provide a code which can be recognized by incoming missiles, guided shells or other ordinance devices. Doublet pulse laser target designators suffer from the disadvantage of requiring almost twice the laser energy per doublet pair,in order to provide range performance equal to a single pulse system.
In a recent development, a large portion of the extra energy requirement is compensated for by the superior efficiency provided by multi-cavity single-pump lasers or single-pump multi-laser systems in which sequentially activated Q-switches are provided in the laser-cavities. In these lasers a single pumping pulse provides the energy for the multiple pulse out-put. Typical efficiency increases measured in the laboratory and during field tests show that doublet pulses generated in this manner contain 50% more energy than those from a single cavity, multi-pump laser or lasers for a given amount of flash lamp energy.
While the multiple cavity, single-pump lasers provide a substantial increase in range, a still further substantial improvement can be obtained by utilizing doublet pulse integration. While the subject invention will be described in terms of two pulses, it will be appreciated that pulse integration of any number of regularly spaced pulses will result in substantial range increases in terms of the range at which a missile carrying a seeker or optical tracking device will lock onto a target illuminated by the multiple pulses.
The purpose of the pulse integration is to time superimpose a first pulse and a second pulse in a doublet pair, such that the signal components add in-phase, while the noise components add in random phase. In the two pulse case, this results in an increase in signal-to-noise ratio (SNR) of at 2 at least 3 db over direct doublet detection, which corresponds to an increase in the lock-on range of approximately 18%.
If pulse integration is utilized, the seeker of the missile will lock on to the target at ranges which exceed that which would ordinarily be achievable by detection of the doublet pulse. Thus, the seeker is able to lock on to relatively weak signals due to the pulse integration technique. In the subject system there are two modes of operation, namely, the short range or doublet decode mode and the long range or extended range mode. In the extended range mode doublet pulse decoding is not utilized, and therefore, there is a certain amount of countermeasure susceptibility at distances which are at the fringe of system performance.
However, in the extended range mode, countermeasure effectiveness is minimized, since even if countermeasuring is employed, the missile will, nonetheless, approach the target. As the missile or guided shell approaches the target, the intensity of the received radiation increases. When this intensity increases above a predetermined threshold, a doublet decoder within the missile's seeker is activated and signals resulting from detected radiation are only gated to the guidance system of the missile if doublet pulses having a known predetermined inter-pulse spacing have been received. Thus, in this embodiment, the seeker system is switched from its long range or extended range mode to its short range or doublet decode mode when the detected signals reach a predetermined threshold. At this point, the seeker is hardened against countermeasuring.
In summary, in the doublet decode mode, each incoming doublet pair is decoded and if the pair has the appropriate inter-pulse spacing the outputs from the pulse integrators are sampled and transmitted to the missile's guidance system. Any signals not having the requisite pulse coding are inhibited from reaching the guidance system of the missile.
The system described, while operating in a long range—short range mode, also has two additional modes of operation. The first mode of operation leaves the pulse integration system in operation all the time, whereas, the second mode of operation disconnects the integration system when the missile is operated in the short range or doublet decode mode. In either case, range extension is achieved by the pulse integration.
Superposition of the first and second pulses is accomplished, in one embodiment, by a recirculating delay line and summation network combination. In another embodiment, the delay line is replaced by a lighter and more versatile device, called a serial analog delay or SAD.
Assuming that the seeker utilizes the conventional quad cell detector, the output from each of these detectors is amplified and mixed in three channels such that if the quad cells are designated A, B, C, and D, then the outputs of the amplifiers are applied to processors which perform the following functions: (A+B)−(C+D); (A+B)−(B+C); and A+B+C+D. This provides three channels of information from the quad cell detector. The first two of these channels constitute the up-down channel and the right-left channels respectively which provide the directional signals for the missile's guidance system.
In one embodiment, the outputs of these processors are applied to respective recirculating delay units each of which have a feedback circuit to a summing network which adds the output of the recirculating delay unit to the incoming signal. The recirculating delay is exactly equal to the expected inter-pulse spacing such that the two;pulses coherently add in the summing network. The output of each recirculating delay unit is applied through a gate to either the up-down or right-left signal channels of the guidance system of the missile.
The third channel is utilized to detect when the missile is within a predetermined short range of the target. This is accomplished by applying the output of this channel to the same type of recirculating delay unit described for the first two channels. The output of this recirculating delay unit is applied to a high level trigger, which, in essence, activates a doublet decoder when the level of the radiation at the seeker reaches a predetermined level indicating that the missile is within a predetermined short range of the target.
In order to provide a signal to the doublet decoder, the third channel is coupled to the doublet decoder. The output of the doublet decoder is applied to a switching or gating system such that the switching or gating system generates a pulse which activates the gates in the first two channels in the presence of an appropriate pulse doublet to sample the quad cell output. When the system is in its short range or doublet decode mode, assuming that the appropriate signals are available at the quad cell, the doublet decoder decodes the fact that the pulses have the requisite interpulse spacing and applies a gating pulse to the gates of the first two channels. The delay throughout the doublet decoder/switching system corresponds to the expected inter-pulse spacing. Thus, if pulses of the appropriate inter-pulse spacing impinge on the quad cell their integrated values will be sampled and transmitted to the guidance system of the missile or ordinance device. Countermeasure signals are rejected by this system and do not affect the guidance system of the missile or ordinance device.
Alternatively, the pulse integration system may be completely taken out of the loop once the doublet mode threshold has been reached. This may have some advantages in close range situations where the signal-to-noise ratio is sufficiently high. However, it will be appreciated that by utilization of the recirculating delay units in the first two channels, an even higher signal-to-noise ratio can be obtained in these channels, with a consequent reduction in the false alarm rate.
It will also be appreciated that the system described includes “preprocessing” the signals from the quad cell detector prior to recirculation. If a recirculating delay line channel is provided for each quad cell detector, the processing for guidance purposes may be accomplished after the pulse integration in a “postprocessing” step.
It is therefore an object of this invention to provide an improved target designating system utilizing pulse integration for extending the range of the system;
It is another object of this invention to provide a target desiganting system which operates in a long range and a short range mode, in which at least the long range mode includes utilization of pulse integration for range extension;
It is another object of this invention to provide a method and apparatus for increasing the signal-to-noise ratio in seekers utilized with multiple pulse target designating systems.
These and other objects of the invention will be better understood in connection with the appended drawings in which: | {
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In earlier years, natural gas was often a nuisance to producers and was burned as a convenient method of disposal. At that time, it was valued at a manufacturing cost of only a few cents per thousand cubic feet. As prices rose, the accuracy of measurement became more important and represented a potentially significant economic loss at every custody transfer point.
Initially, there were few measurement systems although orifice measurement was adopted by the American Gas Association. Venturi nozzles provided good results but were too expensive and needed calibration which was not available in larger sizes. Turbine meters were also available but it was generally accepted that they lacked the necessary degree of accuracy that would permit them to be trusted. As time passed, still other types of meters were introduced and manufacturers were attempting to establish their claims of accuracy.
During these years, those who were buying and selling natural gas have relied on various types of measuring devices. Calibrated liquid filled thermometers have given way to thermocouples and RTD's, pressure gauges have been replaced by pressure transducers and in addition a multitude of special devices have been utilized including gravitometers, densitometers, moisture analyzers and viscosimiters. During this time, the heating value of natural gas was considered, but the difficulty of measurement precluded its widespread use.
Principally, batch calorimeters were known to be available but continuous measurement was at this time first being proposed by Cutler-Hammer. For instance, continuous measurement is contemplated by Cutler-Hammer U.S. Pat. No. 2,238,606 but, while capable of continuous measurement, this device was never in great demand due primarily to its high cost and, in addition, because it required an air conditioned environment for successful operation. Moreover, the Cutler-Hammer device was a large and complicated machine requiring technically qualified operators, high maintenance costs, and a reference gas for calibration.
Nevertheless, the Cutler-Hammer device was considered a standard in the industry until the development of the gas chromatograph. This device does not measure heating value but, rather, does a quantitative chemical analysis. In this manner, the theoretical heating value can be obtained by taking the sum of the values of the different components of the gas.
Among the advantages of the gas chromatograph is its small size and the fact that it does not require an air conditioned environment. It does, however, require a technically trained operator, a certified reference gas and a carrier gas. While its value is recognized by those in the field, the gas chromatograph is limited in usage by a number of considerations, including cost.
In addition to measuring the heating value of a gas, it would also be desirable to measure the heating value of other heating media. This is true in particular of steam since there are many applications in which steam is used for processing and/or heating. However, there has been no truly accurate and effective way of accomplishing this objective.
In view of the foregoing, it has remained to provide a simple, inexpensive calorimeter for measuring the heating value of a heating medium such as gas or steam. In addition, there has been no such calorimeter that can be operated as a stand-alone device with automatic calibration and data transmission to a central processor which can be used particularly effectively at all points in the chain of custody transfer of natural gas from the gas well to the ultimate user. As a result, these are among the principal objects of the present invention as will be apparent from a consideration of the unique features as described hereinafter.
Moreover, since over 95% of all natural gas is used for heating, it follows that gas composition is of little importance in most instances. Thus, it is desirable to avoid the high cost of the gas chromatograph so long as the heating value of gas can be determined at the same or comparable levels of accuracy. Still further, in contrast to the gas chromatograph, it would be desirable to eliminate the need for instruments such as gravitometers, densitometers, moisture analyzers and viscosimiters.
Still further objects of the present invention are automatic calibration and the ability to measure the heating value of a gas at preselected intervals or continuously. | {
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1. Statement of the Technical Field
The inventive arrangements relate to computer network security, and more particularly to methods and systems for controlling dynamic computer networks that maneuver to defeat malicious attacks.
2. Description of the Related Art
The central weakness of current cyber infrastructure is its static nature. Assets receive permanent or infrequently-changing identifications, allowing adversaries nearly unlimited time to probe networks, map and exploit vulnerabilities. Additionally, data traveling between these fixed entities can be captured and attributed. The current approach to cyber security places technologies such as firewalls and intrusion detection systems around fixed assets, and uses encryption to protect data en route. However, this traditional approach is fundamentally flawed because it provides a fixed target for attackers. In today's globally connected communications infrastructure, static networks are vulnerable networks.
The Defense Advanced Research Projects Agency (DARPA) Information Assurance (IA) Program has performed initial research in the area of dynamic network defense. A technique was developed under the Information Assurance Program to dynamically reassign Internet protocol (IP) address space feeding into a pre-designated network enclave for the purpose of confusing any would-be adversaries observing the network. This technique is called dynamic network address transformation (DYNAT). An overview of the DYNAT technology was presented in a published paper by DARPA entitled Dynamic Approaches to Thwart Adversary Intelligence (2001). | {
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1. Field of the Invention
This invention relates to a non-skid, radar absorbing system disposed up on a substrate, its method of making, and a method of using the system.
2. Background Art
Radar absorbing materials (RAMs) are extensively used in various military applications, including stealth technology. They typically are coatings or bulk materials, the electrical and magnetic properties of which have been altered to allow the absorption of microwave energy at discrete or broadband frequencies.
Initial work on producing practical microwave absorbers predates World War II. Early efforts sought to reduce the detectability of a target, of which its radar cross-section (RCS) is a measure. Two types of materials were developed for this purpose. The first was a tuned-frequency, magnetically loaded rubber sheet (Wesch material). The second was a multi-layered material which was relatively thick (Jaumann absorber). It was formed from resistive sheets and low-dielectric plastic spacers.
Over the years, a search has been underway for RAMs that can be used on the surfaces of military targets to prevent them from being detected, located, or recognized by radar over a broad (2-100 GHz) radiation spectrum. But utilization of conventional RAMs generally requires thick applications, particularly at low frequencies. Such an approach creates bulkiness and difficulty in transportation and deployment. Further information about related considerations involving RAMs is found in K. J. Vinoy et al., xe2x80x9cRADAR ABSORBING MATERIALS,xe2x80x9d Kluwer Academic Publishers (1996), which is incorporated by reference.
Another obstacle to the development of satisfactory RAMs has been the effect on radar absorption and reflectance of applying a non-skid coating to the RAM. This is because non-skid materials typically are aggregates that are heterogeneous and have electromagnetic characteristics that are incompatible with RAMs. As a result, the retro reflectance characteristics of RAM may become dramatically altered by the presence of a non-skid layer upon which microwaves impinge. A non-skid coating, however, is necessary for operational field use, particularly under conditions of moisture and motion, in order to provide a safe foot hold for military personnel.
To some extent, the electromagnetic characteristics of the RAM and the non-skid layer are also modified when a protective environmental coating is applied to the non-skid layer.
Prior art references noted during an investigation in connection with the present invention include these U.S. Pat. Nos.: 4,606,848 Bond; 5,552,455 Schuler et al.; 5,844,523 Brennan et al.; 5,892,476 Gindrup et al.; and 5,900,097 Brown.
It is an object of the invention to provide a non-slip or non-skid radar absorbing material (RAM) which will overcome the above and other disadvantages.
More specifically, an object of the invention is to provide a RAM system including a radar absorbing layer, a non-skid matrix layer disposed adjacent thereto, and an optional protective environmental coating applied to the non-skid layer. The RAM system is used on a substrate, often having a non-planar or complex topography. The substrate is representative of the surfaces of military hardware or equipment. Ideally, the overall bulkiness and weight of the system minimize their detrimental effects on the substrate to which the system is applied.
A further object of the invention is to provide a non-skid, RAM system which is capable of both absorbing and scattering incident microwave radiation over a wide spectrum of incident microwave energy, including microwave (2-20 GHz) and millimeter wavelengths (20-100 GHz) frequencies.
A still further objective of the invention is to provide a non-skid, RAM system that includes a protective environmental coating, where the system retains the desired radar attenuating characteristics.
Another object of the invention is to provide methods of making and using a RAM system that can be applied to a non-planar substrate so that the thickness of the system can be controlled within acceptable tolerance limits.
In carrying out the above objects, the non-skid, radar absorbing system of the invention includes a radar absorbing material (RAM) layer juxtaposed with a surface of the hardware or equipment to which the system is applied or affixed. A non-skid matrix layer is disposed adjacent the absorbing layer. Optionally, a protective environmental coating is applied to the non-skid layer. The layers and the topcoat form a radar absorbing system that has electrical and magnetic characteristics that enable microwave energy at discrete or broadband frequencies to be at least partially absorbed.
In one preferred embodiment of the radar absorbing system, the non-skid matrix layer comprises microballoons that alter the dielectric properties of the non-skid coating with minimal added weight.
Another embodiment of the non-skid RAM calls for the non-skid matrix layer to include less than about 5 volume percent of carbon fibers to imbue the system with changed electrical and magnetic properties with minimal further change in weight or volume. If desired, carbon fibers can be added to the non-skid matrix layer, the fibers having an average ratio of length to diameter between about 20 to about 40.
In yet another preferred embodiment, the non-skid matrix layer includes a non-skid additive selected from the group consisting of silicon dioxide, pumice, quartz, aluminum, aluminum oxide, other ceramics, crushed walnuts and mixtures thereof.
In another preferred embodiment of this system, the non-skid RAM is covered with a chemical agent-resisting coating (CARC) as the environmental coating.
Still further preferred modes of practicing the invention include its method of making and use.
The objects, features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. | {
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1. Field of the Invention
The present invention relates to hunting stand devices and more particularly pertains to a new hunting stand device for providing a support and sitting area for a hunter adjacent to a tree and above a ground surface.
2. Description of the Prior Art
The use of hunting stand devices is known in the prior art. U.S. Pat. No. 4,061,202 describes a hunting stand consisting of a collapsible pole having an upper end with hooks for engaging a tree and which includes a plurality of steps attached to and extending laterally away from the pole. Another type of hunting stand device is U.S. Pat. No. 5,791,436 having a plurality of ladder sections that are removably attachable together for forming a climbing member having an upper end forming a seat. Yet another such device is found in U.S. Pat. No. 6,199,660 which includes a ladder having an upper end defining a seat on which a hunter may sit.
While these devices fulfill their respective, particular objectives and requirements, the need remains for a device that allows the hunter to selectively adjust a height of a tree stand and which readily collapses into a relatively small assembly for easy transportation into and out of a forest. The device should also include a collapsible seat and footrest for the comfort of a person using the device. | {
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1. Field of the Invention
The present invention is generally directed to mechanical projectors, more specifically bows, compound bows, and compact compound bows.
2. Description of the Prior Art | {
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1. Field of the Invention
The present invention relates to an accessory tool mounting device for a vacuum cleaner, and more particularly, to an accessory tool mounting device for a vacuum cleaner by which accessory tools can be detachably mounted on a main body of the vacuum cleaner in a more convenient manner and thus it is convenient to store and use the accessory tools.
2. Description of the Prior Art
Referring first to FIG. 6, a conventional vacuum cleaner will be described. As shown in this figure, the vacuum cleaner 1 comprises a main body 10 in which a motor capable of generating suction power, etc. are installed, a connecting hose 14 which is detachably connected to a main body of the vacuum cleaner, an extension tube 11 of which an upper end is formed with a handle 13, and a suction portion 12 installed at a lower end of the extension tube 11.
The connecting hose 14 is detachably connected to the main body through a fitting member 15 which is installed at an end of the connecting hose 14. The suction portion 12 installed at the lower end of the extension tube 11 is a portion that sucks air containing foreign substances while contacting a plane such as a floor with a gap therebetween and moving thereon. The suction portion 12 is configured to be detachably attached to the extension tube 11.
However, since the suction portion 12 is configured to suitably suck the air from the flat floor, it cannot be properly used, for example, in a corner region, for upholstery, or the like. Thus, in addition to the suction portion 12, accessory tools are provided together with the vacuum cleaner. Such accessory tools can be mainly divided into a crevice tool, a dusting brush, and an upholstery nozzle or tool. The accessory tools are used for desired places in a state where each of them is installed at the lower end of the extension tube 11 after separating the suction portion 12 therefrom.
Since the accessory tools are provided separately from the vacuum cleaner, it is common for a user to store the accessory tools separately from the vacuum cleaner. In such a case where the accessory tools are separately stored, there is inconvenience in that in order to use the desired accessory tool, the user should seek it at a separate storage place and install it again. | {
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A programmable logic controller (PLC) is a special form of computer-based controller typically employed to control equipment, machinery and/or instrumentation in automated industrial electromechanical processes. A common example of such an automated industrial electromechanical process is given by the operation of a factory assembly line. In the dynamic environment of a factory assembly line, there may be multiple pieces of industrial equipment, machinery and/or instrumentation (collectively referred to as “equipment” for simplicity) associated with the fabrication, assembly, and/or packaging of parts/components, as well as the transport of the parts/components amongst various stages of fabrication, assembly and/or packaging.
FIG. 1 provides a general illustration of the typical role of a conventional PLC 50 in connection with an automated industrial process 10 such as the operation of a factory assembly line. In addition to multiple pieces of equipment 20, the dynamic environment of a factory assembly line typically includes several control devices 30 (e.g., actuators) for operating the multiple pieces of equipment 20, as well as multiple input devices 40 (e.g., sensors) to provide indications of equipment status and/or various conditions associated with fabrication, assembly, packaging and/or transport of parts/components. Such indications provided by the input devices 40 often are referred to as “states” or “conditions” of the dynamic environment. Some examples of control devices 30 used to operate the equipment 20 include magnetic relays, solenoids, electric motors, and pneumatic or hydraulic cylinders. Some examples of input devices 40 include limit switches, position sensors, analog sensors (e.g., pressure or temperature sensors), and imaging devices (e.g., cameras).
Generally speaking, the PLC 50 is employed to monitor input signals 66 provided by input devices 40. These input signals, respectively or in various combinations, represent different states (conditions) of the dynamic environment as a function of time. In response to the input signals present at a given time, the PLC 50 generates output signals 68 to the control devices 30 for operating the industrial equipment 20, to ensure the automated process 10 is implemented efficiently and predictably. To this end, the PLC 50 generally is employed to coordinate predetermined sequences of actions to be taken by the equipment 20 implementing the process 10, in which respective actions may need to occur within a certain time window contingent on information provided by the input devices 40 (via the input signals 66).
A typical PLC includes programmable memory to store processor-executable instructions and employs various other electronic components to implement functions such as logic, sequencing, timing, counting, and arithmetic. In terms of general architecture and various aspects of functionality, PLCs are in many respects similar to general-purpose computers (e.g., desktop or laptop personal computers); however, whereas general-purpose computers typically are optimized for calculation and display tasks, PLCs generally are optimized for control tasks in a dynamic environment such as an automated industrial process. Accordingly, PLCs generally are thought of as special-purpose control computers for controlled dynamic environments. Since PLCs often are employed in the demanding conditions of an automated industrial process, from a package design standpoint conventional PLCs often tend to be ruggedly designed so as to withstand demanding environments in which the PLC may be exposed to one or more of physical vibrations, challenging temperature and humidity conditions, dust or potentially damaging materials, and electrically noisy environments.
FIG. 2 illustrates a generalized block diagram of the typical electrical components/circuitry (e.g., “hardware”) constituting the conventional PLC 50 of FIG. 1. As shown in FIG. 2, the basic functional components of the PLC 50 include a processor unit 52, memory 54, power supply 56, input interface 58, output interface 60, and one or more communications interfaces 62 all communicatively and/or electrically coupled to one another. FIG. 2 also shows a programming device 64 communicatively coupled to the PLC 50 and employed to program the PLC.
In FIG. 2, the processor unit 52 includes a microprocessor to interpret input signals 66 received by the input interface 58, and in turn provide output signals 68 via the output interface 60 so as to implement control actions according to a program (e.g., series of processor-executable instructions) stored in the memory 54. In particular, the memory 54 stores the program containing instructions representing the control actions to be implemented by the microprocessor, as well as various data relating to input signals, output signals and operation of the microprocessor as it carries out various instructions. The input interface 58 provides to the processor unit 52 information via input signals 66 received from external input devices (e.g., sensors, switches, meters, counters, etc.). The processor unit 52 in turn communicates control actions to external output devices (e.g., valves, motors, etc.) via the output signals 68.
In FIG. 2, examples of components constituting the respective input and output interfaces may include analog-to-digital converters, optocouplers/optoisolators, buffers, latches, and drivers so as to appropriately interface with various external input and output devices associated with the controlled dynamic environment. Although four input signals and four output signals are shown for purposes of illustration in FIG. 2, it should be appreciated that different types of conventionally available PLCs may be configured to accept different numbers of input signals (some number N of input signals) and provide different numbers of output signals (some number X of output signal), and that the number of input signals and output signals need not necessarily be the same. In general, the number N of input signals and the number X of output signals is dictated at least in part by the number of input devices 40 employed to monitor the automated process 10 of FIG. 1 and the number of control devices 30 employed to control the equipment 20.
In the PLC 50 shown in FIG. 2, the communications interface(s) 62 is/are used to receive and transmit various data (which may relate to one or more of the programs for execution by the processor unit 52, the input signals, the output signals, other data to be utilized by the processor unit 52 in executing the program, etc.) via one or more communication networks from or to one or more network-based external input/output devices and/or other remote PLCs. In general, the communications interface(s) 62 implement such functions as device verification, data acquisition, synchronization between user applications, and connection management. The power supply 56 converts AC voltage to a low DC voltage (e.g., 5 Volts) required for the various circuitry in the PLC to operate. Finally, the programming device 64 (which in some examples may be coupled to the PLC 50 via the communication interface(s) 62) is employed to enter into the memory 54 the program to be executed by the processing unit 52; typically, the program is developed/written in the programming device 64 and then transferred to the memory 54 of the PLC 50.
FIG. 3 provides additional details of the internal architecture of the PLC 50 shown in FIG. 2, particularly in connection with the processor unit, various elements of memory, input/output interfaces, and busses to facilitate information transfer. For example, FIG. 3 illustrates that the processor unit 52 (denoted as CPU in FIG. 2) is associated with a clock 52A, the frequency of which determines the operating speed of the PLC and provides the timing and synchronization for various elements in the PLC. Information within the PLC is carried amongst the processor unit, various memory elements, and to and from the input/output interfaces 58 and 60 via multiple busses; in particular, the PLC employs a data bus for transporting data to and from the PLC's constituent elements, an address bus to send the addresses of locations for accessing stored data, and a control bus for signals relating to internal control actions. The PLC architecture also may include an I/O system bus for communications between the input/output interfaces 58 and 60 (from which the input signals 66 are received from external input devices, and the output signals 68 are provided to external output devices, respectively) and an input/output unit 55 configured to transfer input/output information between the I/O system bus and the PLC's data bus.
In general, the processor unit 52 (CPU) of the architecture shown in FIG. 3 includes an arithmetic and logic unit (ALU) that is responsible for data manipulation and carrying out arithmetic operations (e.g., addition, subtraction, multiplication, division) and digital logic operations (e.g., AND, OR, NOT, and EXCLUSIVE-OR), internal memory registers used to store information involved in program execution, and an internal control unit to receive the output of the clock 52A and control the timing of operations. The various memory elements constituting memory 54 may include read-only-memory (ROM) 54A to provide permanent storage for the operating system and fixed data used by the processor unit, user program random-access memory 54B (User program RAM) employed for the program to be executed by the PLC, and data random-access memory 54C (Data RAM) used for data (information regarding the status of input and output signals, values of timers and counters and other internal devices, etc.). The program to be executed by the PLC may also be stored in non-volatile memory.
From the PLC architecture illustrated in FIG. 3, it may be appreciated that although conventional PLCs often are considered special-purpose computers rather than general-purpose computers, both PLCs and general-purpose computers share many aspects of a “Von Neumann” computer architecture. In a Von Neumann computer architecture, computer instructions (the “user program” stored in User program RAM 54A) as well as any data required for program execution (e.g., stored in Data RAM 54C) are accessed from various memory elements over a common bus architecture (i.e., via the address, data and control busses shown in FIG. 3). Although conventional PLCs attempt to tailor computer performance by being special-purpose computing devices implementing specific functionality corresponding to a particular automated industrial process, the architecture of conventional PLCs nonetheless places fundamental limits on their performance, as they execute instructions serially and hence effectively have no capacity for parallel execution.
Programming of a PLC primarily is concerned with specifying digital logic functions that process one or more input signals representing a sensed condition (“state”) associated with the automated process being implemented by various equipment at a given time. The digital logic functions acting on the monitored condition of the automated process generate one or more control signals in response to the monitored condition. As noted above, these control signals are applied to control devices that in turn control the various equipment to take some action involved in further implementing the automated process. At a high level, a PLC program generally implements a sequence of one or more actions in response to monitored conditions as a function of time (e.g., if A or B occurs, actuate C; if A and B occurs, actuate D). The automated process evolves over time as actuators control equipment to drive the process to new conditions. Hence, as noted above, the automated process constitutes a dynamic environment in which an evolution of conditions is monitored by the PLC, and wherein the PLC makes decisions and updates control signals to actuators, based on respective monitored conditions, to drive the environment to new conditions.
Many conventional PLCs are programmed via a “ladder logic” programming language to codify the digital logic that is used to evaluate inputs signals representing monitored conditions. Common ladder logic programming languages typically employ graphical diagrams that resemble “rungs” of a ladder, wherein respective rungs represent circuit diagrams for electromechanical relays (which were used in older logical control systems) to facilitate intuitive programming by control system engineers. Ladder logic is best suited to implement control solutions in which primarily binary variables are involved (e.g., the monitored conditions in a dynamic environment each may be represented as TRUE, i.e., logic one, or FALSE, i.e., logic zero).
However, in a variety of automated process environments, outputs of sensors may be analog signals. Accordingly, in some instances, if the direct output of a given input device/sensor is not in the form of a binary signal, the output of the input device/sensor may be pre-conditioned in some respects to provide the input signals 66 in binary form. For example, an analog output of a temperature sensing device may be first applied to a comparator circuit having a temperature set point voltage as another input so as to provide, as one of the input signals 66, a binary indication of whether or not the monitored temperature is above or below the particular temperature set point. Alternatively, an analog value may be converted to a quantitative value encoded into a multi-bit digital word used by the system to perform mathematical operations and/or make decisions. Similarly, a multi-bit output of a counter serving as an input device may be compared to a pre-determined count to in turn provide, as one of the input signals 66, a binary indication of whether or not the counter output is above or below the pre-determined count (alternatively, an output of a counter having some number B of bits may be provided directly as a number B of input signals 66). Yet other types of input devices may generate highly transient signals; for such devices, a latch may be employed to facilitate the detection of a signal edge or transient so as to provide an input signal of suitable duration to the PLC indicating the occurrence of the edge/transient. In other examples, input devices may include various networked devices, for which one or more communication status signals (e.g., data packet transmitted/received) may serve as one of the input signals 66.
Ladder logic and other languages for programming conventional PLCs generally are considered to be rules-based programming languages. A typical PLC program may be constituted by a series of rules, wherein each rule is constituted by one or more binary input signals (e.g., A, B, C, D) representing a monitored condition of the automated process, and a corresponding control signal (e.g., X) that is generated in response to particular digital logic evaluating the input signals. Accordingly, in some aspects a rule in a PLC program may be viewed in a manner similar to an “IF/THEN” statement (e.g., If (A AND NOT B) AND (C OR D), THEN X). The PLC program includes all of the rules necessary to implement all of the actions that are required in response to different combinations of input signals representing all of the different possible conditions of the automated process that may be monitored via the set of available input signals.
With reference again to FIG. 2, the programming device 64 (which may be a handheld programming device, a desktop console, or a personal computer such as a laptop or tablet computer) is typically employed to create, store and download to the PLC executable programs including a set of rules. When the program is executed by the PLC, the rules are typically executed sequentially from first to last and then repeated, wherein each pass through the set of rules in sequence often is referred to as a “scan” or “control loop.” Thus, consecutive repetitions of the scan or control loop represent a continuous cycle of the PLC reading input signals, examining input signal using the logic encoded in the program rules, and then changing control signals output by the PLC as appropriate.
More specifically, with respect to general operation, including various housekeeping activities and performing scans or control loops, conventional PLCs typically function in a cyclical manner. For example, when power is initially applied to a PLC, the PLC may perform a self-check or diagnostic routine to ensure that various hardware components are functioning properly. With reference again to FIGS. 2 and 3, if no fault or error conditions are detected, the PLC then controls the input interface 58 and memory 54 so as to read each of the input signals 66 sequentially and store each read instance of a given input signal in a dedicated memory location. The PLC then executes its program by sequentially testing each rule (i.e., fetching, decoding and executing the program instructions in sequence) and solving the logic encoded in the rule.
In particular, for each rule, the stored instances of certain input signals as specified in the rule are retrieved from memory, the rule is evaluated based on the retrieved input signals, and if the rule is satisfied (i.e., all of the pre-requisite conditions specified in the rule are met), a control signal corresponding to the satisfaction of the rule is generated. If such a control signal is generated, it is stored in a dedicated memory location. Evaluation of a given rule may involve multiple read operations from, and write operations to, different memory locations (e.g., registers) as the digital logic codified in the rule is solved. As noted above, respective rules are evaluated sequentially as the PLC executes the ladder logic program; accordingly, while the PLC is evaluating a particular rule, it is inattentive to the other rules codified in the program.
If the PLC generates any control signals in response to evaluation of the rules, it may provide these for output as a set of updated control signals 68. These control signals in turn are transmitted to one or more actuators or other equipment to be controlled in connection with the automated process. The PLC then returns to performing the self-check, reading each of the input signals and storing them to memory, executing the program rules to complete the control loop, updating the control signals for output (if any), and repeating this cycle iteratively.
The time period required by the PLC to complete the cycle described above commonly is referred to as a “cycle time” or “scan time.” Typical cycle times of conventional PLCs are on the order of approximately 10 milliseconds to hundreds of milliseconds. The cycle time generally is determined by the particular CPU used in the processor unit, the size of the program to be scanned (e.g., the number of rules constituting the program, which in turn depends at least in part on the number of input signals to be read, the number of input signal combinations for which independent evaluations are required, and the number of control signals to be generated), and the system functions that are in use pursuant to execution of the program. Thus, the more complex the program, the longer the cycle time will be.
It should be appreciated that, in a conventional PLC, the vast majority of rules when evaluated in a given cycle are not satisfied (i.e., no control signal is generated pursuant to evaluation of the rule); if a rule is not satisfied, the program merely moves to the next rule for evaluation. In this manner, it is common in conventional PLCs for a substantial portion of a given cycle to be spent evaluating successive rules without generating any control signals.
Although relatively quick compared to general-purpose computers programmed to implement similar functionality, the cycle time of a PLC is not instantaneous. As a result, the PLC does not “watch” its input signals all of the time, but instead the PLC samples the states of the input signals periodically depending on the cycle time. Furthermore, the cycle time constitutes a minimum delay in updating control signals (if generated pursuant to a satisfied rule) that are output by the PLC in response to sampled input signals. In this manner, the cycle time also may be viewed as a minimum response time (a “reaction time”) of the PLC to a particular monitored condition (i.e., represented by a particular value for one or more of the input signals), and is often referred to as a “latency” of the PLC. Thus, it should be appreciated that due to this latency, an input signal that lasts for a duration shorter than the cycle time may be missed by the program (in general, any input signal must be present for longer than the cycle time). In some instances, external circuitry may be employed to latch transient signals so that they will not be missed entirely by the PLC. Even if a particular input signal is not “missed” due to latching, however, a control signal that is to be generated in response to the input signal may be generated by the PLC too late to be effective for the correct operation of the equipment being controlled.
Because of the cyclical nature in which a conventional PLC executes a program, all possible combinations of input signals (representing all possible conditions of the automated process being controlled for which some action is required) must be contemplated in a single control loop of the program. Stated differently, as noted above, as long as a monitored condition represented by one or more input signals is in some manner involved in causing some action to occur (via one or more control signals) at some point during the duration of an automated process, there needs to be one or more rules in the program that evaluate the particular monitored condition. As noted above, the latency of a conventional PLC scales with program complexity; hence, as the number of possible conditions of the process for which actions are required increases, the program becomes larger and the latency becomes greater. Furthermore, in many automated processes, some conditions occur more frequently than others, and in some instances conditions that may occur rarely may be associated with a rule representing complicated logic that needs to be evaluated (which requires more processing time). Accordingly, significant portions of the cycle time may be “used up” (and latency exacerbated) by executing one or more rules to evaluate one or more monitored conditions that occur rarely. | {
"pile_set_name": "USPTO Backgrounds"
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Access technologies of various kinds, especially wireless, are becoming increasingly ubiquitous, e.g. in the shape of GSM (Global System for Mobile communication)/GPRS (General Packet Radio Service)/EDGE (Enhanced Data rates for GSM Evolution), WCDMA (Wideband Code Division Multiple Access)/HSPA (High Speed Packet Access), CDMA2000 (a cellular network standard based on Code Division Multiple Access), WLAN (Wireless Local Area Network), WiMAX (Worldwide Interoperability for Microwave Access) and soon LTE (Long Term Evolution). The mobile terminals or other types of user equipment (UE) match this multitude of access technologies by including ever more access interfaces to allow greater freedom and flexibility in the selection of access to use for each communication session.
To leverage the benefits of this growing flexibility it becomes important to have mechanisms in place for efficient control of the access selection, to ensure that a mobile node always uses its available access interfaces and access networks as efficiently as possible for the currently ongoing communication sessions. Circumstances to be taken into account include, e.g., the currently used applications, access network technologies and their properties, access network operators (and their relations to the user's home operator and/or the user), current network conditions (e.g. load), location, subscription restrictions, time of day, etc. Similarly, it is desirable to support a mobile node in discovering available accesses without requiring the mobile node to continuously scan for all accesses and thus using battery resources.
In SAE (System Architecture Evolution)/LTE, also known as EPS (Evolved Packet System), i.e. the future evolved 3GPP system, multi-access is a key element. Control of access selection (and access discovery) is recognized as an important aspect and has been assigned a dedicated work item in the 3GPP standardization process.
The mechanisms considered are based on policies and/or rules. The functionality provided by a policy/rule is instructions or guidance of which access to select or how to discover accesses given the specific circumstances (device context). A policy/rule typically defines contextual conditions when it applies (e.g. for a certain application, in a certain geographical region, a certain time of day and/or day of the week, the PLMN (Public Land Mobile Network) the UE is currently registered at, e.g. a visited PLMN during roaming, etc.) and access preferences. The access preferences may e.g. be a prioritized list of accesses, an indication of a specific only access, a list of prohibited accesses, or some other way of expressing how preferable certain accesses are.
There are three basic cases of access selection: Selection between multiple 3GPP accesses, e.g. LTE, HSPA, WCDMA, GERAN (GSM EDGE Radio Access Network), GSM. This access selection case may also comprise the 3GPP2 (3rd Generation Partnership Project 2) access CDMA2000, but for simplicity it is referred to as “intra-3GPP access selection” or simply “3GPP access selection”. Selection between 3GPP and non-3GPP access(es) (where non-3GPP accesses include e.g. WiMAX and WLAN). This access selection case is referred to as “extra-3GPP access selection”. Selection between multiple non-3GPP accesses. This access selection case is referred to as “non-3GPP access selection”.
Extra-3GPP access selection and non-3GPP access selection are also collectively referred to as “ANDSF based access selection”, because, as will be explained later, they are controlled by the functionality provided by the Access Network Discovery and Selection Function (ANDSF). Accordingly, in the following extra-3GPP access selection and non-3GPP access selection are for reasons of simplicity also collectively referred to as “ANDSF based access selection”.
Policies and/or rules may be processed in the network, e.g. in the PCRF (Policy and Charging Rules Function) or, in the context of access selection, for example in the newly introduced functional entity ANDSF, which is responsible for extra-3GPP access selection as well as non-3GPP access selection, i.e. access selection between 3GPP accesses and non-3GPP accesses and between different non-3GPP accesses. The ANDSF can be distributed between the mobile node or UE and the network. In the network the ANDSF can be located both in the home network and in the visited network. The ANDSF functionality in the UE is referred to as ueANDSF, the ANDSF functionality in the home network is referred to as hANDSF, and the ANDSF functionality in the visited network is referred to as vANDSF. The network ANDSF can be located in an entity inside (i.e. as an integral part of) or can be associated with the PCRF. It is also possible that there will be ANDSF related functionality in non-3GPP access networks, e.g. for provision of access properties as input data to the access selection process. Such possible ANDSF related functionality in non-3GPP access networks is herein tentatively labeled n3aANDSF. Further information on the introduction of the ANDSF in the 3GPP SAE architecture, as well as the related information flows, can, e.g. be found in “3GPP TS 23.402 v8.1.1, ‘3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Architecture enhancements for non-3GPP accesses (Release 8)’, March 2008”.
For 3GPP access selection, i.e. selection between different 3GPP accesses that interwork on radio access network (RAN) level (such as LTE, WCDMA/HSPA and GERAN, and possibly the 3GPP2 access CDMA2000), the access selection functionality is separate from the ANDSF. This access selection function is network based and is typically located within the RANs, e.g. E-UTRAN (Evolved Universal Terrestrial Radio Access Network), GERAN, UTRAN (Universal Terrestrial Radio Access Network), CDMA2000-RAN, and possibly partly also in the MME (Mobility Management Entity) and/or SGSN (Serving GPRS Support Node). Potentially, processing of access selection related policies and rules may take place also in this access selection function.
The ways the 3GPP access selection functionality controls the access selection of the UEs differ between connected-mode and idle-mode UEs. Here, “connected-mode UEs” refers to UEs in connected mode, which have a signaling connection established to a RAN.
Access selection for connected-mode UEs is manifested as handovers between different accesses. This is, e.g., explained in “3GPP TS 36.300 v8.4.0, ‘3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Access Network (E-UTRAN); Overall description; Stage 2 (Release 8)’, March 2008” and in “3GPP TS 36.331 v8.1.0, ‘3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA) Radio Resource Control (RRC); Protocol specification (Release 8)’, March 2008”. The handovers are network controlled, but aided by measurement reports (e.g. received signal power from neighbor cells) from the UEs. The network sets the trigger criteria for the UEs' measurement reports (through broadcasting of thresholds and/or by sending UE specific criteria to individual UEs) and also determines when and to which cell (and access network) a handover should be performed.
For idle-mode UEs access selection is realized as cell reselection, i.e. repeatedly evaluating the best cell to camp on, as well as access technology (or Radio Access Technology, RAT) selection. This is, e.g., explained in “3GPP TS 36.304 v.8.1.0, ‘3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode (Release 8)’, March 2008”. The network broadcasts (in the system information) the signal strength threshold levels determining when the UEs should evaluate neighbor cells for cell reselection. The network can also provide RAT and carrier frequency priorities in the broadcast system information and optionally in a UE specific signaling message when the RRC (Radio Resource Control) connection to the RAN is released.
For initial selection of PLMN and preferred access technology, e.g. when the UE is powered on, the UE is typically guided by information stored on the SIM card (SIM: Subscriber Identity Module) or USIM card (USIM: Universal Subscriber Identity Module). This is, e.g., explained in “3GPP TS 36.304 v.8.1.0, ‘3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) procedures in idle mode (Release 8)’, March 2008” and in “3GPP TS 23.122 v8.1.1, ‘3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) functions related to Mobile Station (MS) in idle mode (Release 8)’, March 2008”). This information originate from the operator (i.e. the operator with which the SIM/USIM card is associated), but may be complemented with information from the user. The user can also choose to make the initial selection purely manual.
An advantage of keeping the 3GPP access selection functionality distinct from the ANDSF based access selection functionality is that both selection functionalities can be optimized in this way for different time scales and/or interfaces. As an example, ANDSF communication may take place on a long time scale, possibly minutes, hours or even months. Thus updates of the rules can be comparatively seldom and may be transported easily by the IP protocol. In contrast, 3GPP access selection may be optimized for a synchronization of communications based on timeslots of the access systems, typically on the order of several milliseconds. In this way, a UE can for example perform measurements on one access systems during short intervals in a transmission over a different 3GPP access system. This allows the preparation of inter-system handovers even for a UE with only a single transceiver but requires elaborate interfaces.
Access selection and access discovery are not restricted to mobile or wireless nodes/terminals. They are equally applicable for so called “user networks”. The term user network (UN) refers to one or more inter-connected user devices that can access a network via one or more access technologies. Examples of a single-device user network are a cellular phone or a laptop, while an example of a multi-device user network is a Personal Area Network (PAN). Although only the term UE will henceforth be used in this document, it should be interpreted as either a single device, i.e. a mobile terminal, or a multi-device user network.
The problem with the existing solution is that because the two access selection mechanisms are separate, access selection loops may occur in some situations. To illustrate this problem consider the following example.
In a certain situation (defined by context parameters, e.g. active applications, time of day, etc.) the 3GPP access selection functionality has the following prioritized access preference list (most preferred first):
1. WCDMA
2. LTE
3. GERAN
Reasons for this priority order may include policies for load balancing or steering of certain applications to certain access networks (e.g. running voice calls over circuit switched WCDMA bearers).
In the same situation the ANDSF based access selection functionality has the following prioritized access preference list (most preferred first):
1. Corporate WLAN
2. 3GPP domain if 3GPP access=LTE is available
3. WiMAX
4. 3GPP domain if 3GPP access=WCDMA or GERAN is available
Initially we assume that the concerned UE is connected to the 3GPP domain. Within the 3GPP domain the 3GPP access selection mechanism directs the UE to WCDMA (even if LTE is available in the current location), because this is the highest priority 3GPP access (in the given situation).
The UE detects an available WiMAX access and the ANDSF based access selection mechanism determines to leave the 3GPP domain and hands over the UE to the WiMAX access, because it has a higher priority than a 3GPP domain represented by WCDMA.
While the UE is connected to WiMAX it scans for higher priority access networks. It detects LTE but no corporate WLAN and thus, in accordance with its prioritized access preference list, the ANDSF based access selection functionality hands over the UE to LTE in the 3GPP domain.
Once connected to the 3GPP domain the above described mechanisms used by the 3GPP access selection functionality kicks in and directs the UE to WCDMA, thereby forming a potentially endless access selection loop.
Accordingly, there exists a need to provide improved techniques for access network selection in a multi-access network environment which provides multiple independent access selection processes. | {
"pile_set_name": "USPTO Backgrounds"
} |
High strength polymeric materials are being increasingly used to replace traditional structural materials, such as metal, in many applications. The polymeric materials have the advantage of lower weight and are often less expensive and more durable than metals. However, polymeric materials tend to be much lower in strength than metal. Unless polymeric materials are reinforced in some manner, they often do not meet the strength requirements for metal replacement.
Thus, polymeric composites have been developed to meet such strength requirements. These composites are characterized by having a continuous polymeric matrix within which is embedded a reinforcement material, which is usually a relatively rigid, high aspect ratio material such as glass fibers.
Such composites are typically molded into a predetermined shape, which is in many cases asymmetric. To place the reinforcement material into the composite, the reinforcement material is usually placed into the mold in a first step, followed by closing the mold and then introducing a fluid molding resin. The molding resin fills the mold, including the interstices between the fibers, and hardens (by cooling or curing) to form the desired composite. Alternatively, the molding resin can be applied to the reinforcing fiber prior to molding. The reinforcing fiber with resin thereon is then placed into a mold where temperature and pressure are applied, curing the resin to prepare the desired composite.
It is desirable to uniformly distribute the reinforcement material throughout the composite. Otherwise, the composite will have weak spots where the reinforcement is lacking. Thus, it is important to prepare the reinforcement material so that the individual fibers are distributed evenly throughout the composite. In addition, the individual fibers should be held in place to resist flowing with the molding resin as it enters the mold, which would disrupt the fiber distribution.
For these reasons, reinforcement has been conventionally formed into a mat outside of the mold. The preform mat is then placed in the mold and either impregnated with resin to make the final composite article, or simply heated and pressed to make a very low density composite article. The mat is generally prepared by forming the reinforcing fibers into a shape matching the inside of the mold and applying a binder to the fibers. In some instances, a thermosetting binder is pre-applied, and then cured after the fibers are shaped into a mat.
In other methods, a thermoplastic binder is applied, so that in a subsequent operation the binder can be heated and softened and the mat subsequently shaped. This binder “glues” the individual fibers to each other so that the resulting mat retains its shape when it is transferred to the mold for further processing. The binder also helps the individual fibers retain their positions when the fluid molding resin is introduced into the mold. In some cases, a molding resin can alternatively be applied to the reinforcing fiber prior to molding. The fiber with binder and resin is placed into a mold where temperature and pressure are then applied, curing the resin to prepare the desired composite.
Binders conventionally used have been primarily of three types, each of which have various drawbacks. The predominantly used binders have been solvent-borne polymers, i.e., liquids, such as epoxy and polyester resins. The solvent-borne binders are usually sprayed onto the mat via an “air-directed” method, and then the mat is heated to volatilize the solvent and, if necessary, cure the binder. This means that the application of binder is at least a two-step process, which is not desirable from an economic standpoint. Also, the use of solvents is encountered, which raises environmental, exposure and recovery issues. Dealing with these issues potentially adds significantly to the expense of the process. The procedure is also energy intensive, as the entire mat must be heated just to flash off solvent and cure the binder. The curing step also makes the process take longer.
Use of the solvent-borne polymer binders is extremely messy. There are also high maintenance costs associated with keeping the work area and the screen on which the mat is formed clean. In this case, where the binder may be low viscosity fluid, it tends to flow over and coat a large portion of the surface of the fibers. When a composite article is then prepared from a preform made in this way, the binder often interferes with the adhesion between the fibers and the continuous polymer phase, to the detriment of the physical properties of the final composite.
A second form of binder is powdered binders. These can be mixed with the fibers, and then the mass formed into a preform shape, which is heated to cure the binder in situ. Alternatively, these binders can be sprayed to contact the fibers. However, simply substituting a powdered binder in an air-directed method raises problems. For example, powdered binders cannot be applied unless a veil is first applied to the screen to prevent the binder particles from being sucked through. Again, this adds to the overall cost and adds a step to the process. Airborne powders may also present a health and explosion hazard, depending on conditions of use. The use of powdered binders additionally requires a heating step to melt the binder particles after they are applied to the fibers. Heating renders this process energy-intensive.
Binders of a third type are heated thermoplastic materials, which can be melted and sprayed as a binder. Use of these materials makes any subsequent heating step unnecessary, since the binder does not require heat to achieve some undetermined measure of adhesion to the fibers. This method has problems with “lofting,” or inadequate compaction of the preform. Lofting typically occurs because the thermoplastics are conventionally heated to any random temperature above their melting points, leading to a lack of uniformity in their cooling patterns and extensive migration along fiber surfaces. This allows some of the fibers to “bounce back” before they are set into place by the solidifying thermoplastic. This may result in formation of a lower density preform than desired, density gradients throughout the preform, and poor adhesion of the fibers to each other.
In view of the problems discussed herein, one prior art method disclosed in U.S. Pat. No. 6,030,575, which is incorporated herein by reference, applies a heated binder to fibers already supported on a support surface while a vacuum is applied to the other side of the support surface. By this method, the fibers are held in place by the vacuum while the binder is applied at a high pressure by a spray device. This application applies pressure to the fibers thus forming a solid reinforcing structure. Upon application, and with the assistance of the air flow from the vacuum, the binder cools and solidifies into the desired preform shape. However, the application of the vacuum requires additional equipment in the form of a plenum arrangement and also requires additional control functions and labor to properly apply the fibers and vacuum. Therefore, the material and operating costs are increased.
In view of these prior art methods, it would be desirable to provide a simpler apparatus and a method for making preforms in which the problems associated with using solvent-borne, powdered or thermoplastic binders are minimized or overcome. It would also be desirable to provide apparatus and a method in which sagging, slumping, and separating of perform materials from tall vertical or nearly vertical surfaces is avoided. It would also be desirable to provide a lower cost method that is simple to operate and thus more conducive to automation. In a more simple forming process, it may even be possible to eliminate the need to transfer the preform to a molding tool and/or eliminate the need to apply a vacuum to the forming surface. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention relates to an apparatus for plating wafers for semiconductors, more particularly to a cup-type plating apparatus in which the wafer is placed on an opening of a plating tank and is subjected to plating.
2. Description of the Related Art
Recently, various kinds of plating, for example, formation of a bump, are performed in the manufacturing process of wafers for semiconductors. A cup-type plating apparatus is known as one of the apparatuses for plating the wafer.
In this cup-type plating apparatus, a plating solution is supplied to a wafer, which is placed on a wafer support provided along an opening at the top of a plating tank, via a solution-supply port provided at the bottom of the plating tank by an upward-moving stream, and flows out of a solution-outlet port provided for the plating tank; thus, plating is performed while bringing the plating solution into contact with a surface of the placed wafer to be plated.
In the cup-type plating apparatus, the plating solution supplied toward the surface of the wafer to be plated, by the upward-moving stream makes the plating solution into contact with the surface to be plated in a flowing state in which the solution spreads out from the center toward the periphery of the surface; thus, uniform plating can be performed on the entire surface to be plated. Since plating can be performed in such a manner that the wafer to be placed on the wafer support of the plating tank is successively replaced, the apparatus is widely used as a suitable apparatus for small-lot production or automatization of plating process.
In the conventional cup-type plating apparatus, the plating solution supplied from the solution-supply port by the upward-moving stream is flowed out from the solution-outlet port provided over the plating tank in a state in which the plating solution is directly exposed. Therefore, in this cup-type plating apparatus, a mist of the plating solutions may be generated due to the plating solution which flowed out of the plating tank, and may adhere to the surface (the rear of the surface to be plated) of the wafer placed on the wafer support. Conventionally, since the contaminant on the surface of the wafer due to the mist of the plating solutions is removed in a later cleaning process, it has not been perceived to pose a particular problem.
The development of plating process in which more wafers can be speedily processed is in progress as a demand for the wafers rapidly increases. As an example, the supply of the plating solution or the current density for plating is increased for realizing high-speed plating. When the supply of the plating solution is increased, the mist of the plating solutions is also increased, and the contaminant on the surface of the wafer resulting from the mist is more prominent than it was; thus, the necessity for afterward careful cleaning arises.
Since a large number of wafers are plated at the same time, a plating unit having a plurality of cup-type plating apparatuses may be manufactured, thereby realizing an efficient plating process. In this case, a large amount of the mist of the plating solutions is likely to be generated at a time due to the plating solution flowing out of a plurality of the plating tanks, and consequently, the contaminant on the surface of the wafer is likely to be increased.
Furthermore, the recent wafer manufacturing process is almost automated; wherein the wafers are successively moved in the processes, and in many cases, after completion of plating, the cleaned and dried wafers are moved to a clean room, and a downstream process is then performed. Therefore, when no measures against the mist of the plating solutions is taken, for instance, when a large amount of mist of the plating solutions exists in the plating process, it may leak into the clean room to generate contamination in the clean room; and, accordingly, it is not preferable for manufacturing wafers.
In the recent wafer-manufacturing process, because of the foregoing reasons, a cup-type plating apparatus in which the contamination on the surface of a wafer due to a mist of plating solutions can be prevented as much as possible is strongly required. Accordingly, it is an object of the present invention to provide a technique in which the conventional cup-type plating apparatus is improved, and the contamination on the surface of the wafer due to the mist of the plating solutions can be prevented.
In order to achieve the above object of the present invention, a plating solution is supplied to a wafer which is placed on a wafer support provided along an opening at the top of a plating tank from a solution-supply port provided at the bottom of the plating tank by an upward-moving stream; the plating solution is made to flow out of a solution-outlet port provided for the plating tank; and plating is performed while the plating solution is brought into contact with a surface of the placed wafer, which is to be plated; wherein the solution-outlet port has a solution-outlet path in which the discharged plating solution is isolated from the outer space.
In the cup-type plating apparatus according to the present invention, since the plating solution flowing out of the plating tank is in a state isolated from the outer space, that is, a state separated from the space in which the surface (the rear of the surface to be plated) of the wafer placed on the wafer support is exposed, the contamination on the surface of the wafer due to the mist of the plating solutions can be prevented.
The structure of the solution-outlet path according to the cup-type plating apparatus in the present invention is not particularly limited as long as the it is a structure in which the plating solution flowing out of the solution-outlet port which is provided for the plating tank is isolated from the outer space, that is, it does not directly come into contact with the outer space. For example, an outlet pipe may be provided as the solution-outlet path in such a manner that it is connected to the solution-outlet port provided for the plating tank; alternatively, a solution-outlet path may be provided in which a cover case capable of covering the outer periphery of the plating tank, so that the plating solution flowing out of the solution-outlet port can be isolated from the outer space.
In the cup-type plating apparatus according to the present invention, preferably, the solution-outlet path passes through the interior of the wall of the tank from the solution-outlet port provided on the side of the inner periphery of the wall of the tank, which constructs the plating tank. Thus, the solution-outlet path in which the plating solution can pass through is provided in the interior of the wall of the tank, which constructs the plating tank, so that the plating solution flowing out of the solution-outlet port provided on the inner periphery of the wall of the tank is isolated from the outer space. Accordingly, a space for providing the solution-outlet path on the outside of the plating tank is not required, and the cup-type plating apparatus itself can be made compact. It is particularly effective when constructing a plating unit having a plurality of the cup-type plating apparatuses.
In order to reliably prevent the contamination on the surface of the wafer due to the mist of the plating solutions, preferably, a shutting means capable of closing the opening of the plating tank is provided. In the cup-type plating apparatus, while plating is performed in such a manner that the wafer which is placed on the wafer support provided along the opening of the plating tank is successively replaced, the opening of the plating tank is in an opened state during replacement. At this time, the mist of the plating solutions leaks a little from the opening into the outer space. When replacing of the wafer is completed in a relatively short time, that is, the time of opening the opening is short, it has little effect on the contamination on the surface of the wafer; however, when replacing of the wafer requires a long time, that is, when the opening is opened for a long time, the amount of mist of the plating solutions which leaks out is increased, and accordingly, there is a fear that it exerts an influence on the contamination on the surface of the wafer. Therefore, when the opening of the plating tank is closed when necessary by the shutting means capable of closing the opening of the plating tank, the contamination on the surface of the wafer due to the mist of the plating solutions can be further reliably prevented. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates generally to electric metering devices and more specifically to heat management for electronics within such devices.
Traditional utility meters for the measurement of electricity primarily employed mechanical registers and devices. While electricity meters always contained devices that sense electrical energy, the registration of such sensed energy was often carried out mechanically using gears and dials. More recently, utility meters have increasingly relied upon electronic circuits that provide enhanced functionality. At present, electricity meters often contain one or more circuit boards that provide advanced consumption registration functions, automatic meter reading functions, diagnostics, profiling and other beneficial functions.
A problem sometimes encountered with utility meters that employ electronic circuits is excessive temperature rise inside the cover of the meter due to heat generated by electronic components and by other electrical components within the meter. As internal temperature rises, the life expectancy of the electronic components is reduced. Consequently it is desirable to limit the increase in temperature in the area of electronic components. Unfortunately, electric meters must be enclosed in such a manner as to pass the metering industry's weatherization standards, which require meter enclosures to be sealed from dust and water. Such weathering requirements prevent the addition of air vents or other traditional means of reducing internal temperature rise of electronic devices.
As a consequence, the amount and/or functionality of electronic circuitry within meters may be limited at least partly by the associated heat rise caused by additional circuitry and/or functionality. Limiting functionality is important because the same component, such as a processor, can generate more or less heat based on its usage.
Accordingly, it would be desirable to provide advanced functionality associated with contemporary electronics, while maintaining ambient conditions for electronic devices within the utility meter enclosure at an appropriate level for sustaining rated life of the electronic components. | {
"pile_set_name": "USPTO Backgrounds"
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The invention relates to a method for operating a drive device of a vehicle, in particular a motor vehicle, which has at least one electric or hydraulic machine as a drive unit. In addition, the invention relates to a corresponding device and to a system.
Modern motor vehicle drive trains usually do not have direct measurement of currently generated drive torques for reasons of cost. The torque output or power output of a drive unit therefore cannot be determined directly. In particular in the case of hybrid vehicles or electric vehicles whose drive devices have at least one electric or hydraulic machine as a drive unit, in particular in addition to a conventional internal combustion engine, there can be frictional engagement between one or more of these drive units and the driven wheels of the motor vehicle even in the case of a stationary vehicle. A faulty torque output or power output of the at least one drive unit, for example owing to a communication error or a software error or fault in an on-board component, can cause a safety-critical incorrect movement of the vehicle. In the case of vehicles with an electric or hydraulic machine as a drive unit, a reverse gear speed in the transmission is frequently dispensed with if such a reverse gear speed is provided at all. If a reverse gear speed is desired in this case, a change of direction of rotation of the drive unit takes place compared to the direction of rotation in the case of forward travel. The change in the direction of rotation is brought about by a changed actuation, for example by a changed direction of rotation of the magnetic field of a three-phase machine which is provided as a drive unit. In addition to component faults or software errors, faults in the power cabling, the sensor cables of a rotor position sensor or rotational speed sensor or incorrect orientation of sensor components relative to the shaft or to the housing of the drive unit can lead to a torque which acts in the wrong direction. When the vehicle starts, this would lead to a vehicle movement in the wrong direction of travel. In particular if persons are located in the vicinity of the vehicle, this results in a situation which is extremely safety-critical. | {
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In recent years, a polyorganosiloxane has attracted attentions as a material having good light permeability, good heat resistance, low gas permeability and good chemical stability. Polyorganosiloxanes having various properties are provided by changing a type of siloxane monomers, composition of raw materials and reaction conditions in the production process. On account of this, polyorganosiloxanes have been put to practical use in the various fields.
The organopolysiloxane is generally prepared by hydrolysis and condensation reaction which are caused by contacting a chlorosilane and/or alkoxysilane with a stoichiometric amount of water in an organic solvent and in the presence of an acid or base catalyst. However, in this method, a significant amount of silanol groups remains often in the obtained polyorganosiloxane and react between each other in storage to increase the viscosity to cause a problem in storage stability. Further, the unstable silanol group remaining in the polymer may cause cracks and decrease of the adhesiveness in a longterm use. Further, because the polyorganosiloxane obtained from the hydrolysis and condensation reaction has a random structure, polyorganosiloxane with desired properties is not always obtained.
Examples of the other methods for preparing a polyorganosiloxane include a method where an organic silicon compound having a silanol group, i.e., —SiOH, condensation reacts with each other in the presence of catalyst; a method where an organic silicon compound having a silanol group, i.e., —SiOH, condensation reacts with an organic silicon compound having an alkoxysilyl group, i.e., —SiOR, in the presence of catalyst; and a method where an organic silicon compound having a alkoxysilyl group, i.e., —SiOR, condensation reacts with each other in the presence of catalyst, wherein R represents an alkyl group or an alkokyalkyl group. In the aforesaid condensation reactions, an amount of a silanol group remaining in the polyoraganosiloxane obtained is small. However, these methods need chemically fierce catalysts to cause condensation reaction, for instance, strong acids such as sulfuric acid and hydrochloric acid; strong bases such as sodium hydroxide, potassium hydroxide and tetramethylammonium hydroxide; and Lewis acids. When the aforesaid catalysts are used, siloxane bonds (Si—O—Si) are cut to cause rearrangement during the reaction and, therefore, the polyorganosiloxane obtained has a random structure.
Japanese Patent Application Laid-Open No. H02-235933 describes that a borate or phosphate of sodium or potassium is used as a catalyst and a silanol-containing siloxanes is subjected to a condensation reaction in the presence of the catalyst to prepare an organosilicone condensate. Japanese Patent Application Laid-Open No. H03-197486 describes that silanol-containing siloxanes is subjected to a condensation reaction in the presence of a catalyst selected from the group consisting hydroxide, chloride, oxide and basic metal salt of an alkali metal or alkaline-earth metal to prepare a polyorganosiloxane. Japanese National Phase Publication No. 2006-508216 describes that hydroxide of magnesium or calcium can work as a catalyst in condition of the presence of a protonic solvent to promote a condensation reaction between a silanol-containing siloxane and an alkoxysilane. Japanese National Phase Publication No. 2010-506982 describes that a silicon containing compound having a silanol group and/or an alkoxysilyl group reacts in the presence of a catalyst selected from the group consisting of strontium oxide, barium oxide, strontium hydroxide, barium hydroxide and a mixture thereof to prepare an organosilicone condensate.
In the methods described in the afore-mentioned patent literatures, rearrangement of the polyorganosiloxane chain is minimized and, thus, a polyorganosiloxane having a controlled structure is obtained. Further, these methods have an advantage that the catalyst can be easily separated from the obtained polyorganosiloxane by filtration because these catalysts are solid. These advantages are favorable particularly in fields where accurate control on materials is required and no remaining impurity is tolerable, for instance, the fields of optical materials, electronic materials and medical materials. | {
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German Patent Specification DE No. 3,143,121 which corresponds to U.S. Pat. No. 4,440,833, describes such a synthetic resin composition and a fibrous substrate material for printed circuit boards, in particular paper, in which a phenol-formaldehyde resin is impregnated which is mixed with a softening polyurethane component to allow for, for example, holes to be punched or pierced in the material without the substrate material becoming torn at the edges of the holes.
A disadvantage of such a material to which a softener is added, is the higher degree of sagging of the material, in particular at a higher temperature, for example, over a wavesoldering bath as used to attach electric and electronic components to the printed circuit board. | {
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1. Field of the Invention
The present invention relates to a wireless communication apparatus, and more particularly, to a wireless communication apparatus capable of performing a mutual communication according to a sniff parameter calculated based on the information with respect to sniff slave apparatuses connected with a master apparatus in a sniff mode for performing a communication for a determined time between the master apparatus and the slave apparatuses. The present application is based on Korean Application No. 2001-53176, filed Aug. 31, 2001, which is incorporated herein by reference.
2. Description of the Related Art
Bluetooth is a communication technology capable of transmitting wirelessly information such as letter data, sound data, and video data at a distance of 10 to 100 m.
A Bluetooth apparatus, which can mutually communicate according to the Bluetooth communication method, sets up a connection status that communicates through operations such as an inquiry, an inquiry scan, a page, and a page scan. From this process, a master apparatus and a slave apparatus are determined according to their respective roles.
When a new connection status is set up between the Bluetooth apparatuses, an operation clock and a frequency pattern should be adjusted between the Bluetooth apparatuses. In the process for setting up the connection status, the inquiry is an operation of repeatedly sending an operation frequency from the master apparatus so that the slave apparatus can adjust the frequency pattern with the master apparatus. The inquiry scan is a process performed in the slave apparatus. The inquiry scan detects a transmitted frequency, and adjusts a synchronism with the detected frequency. The page is a process for sending a clock signal from the master apparatus so that the slave apparatus can adjust for the operation clock of the master apparatus. The page scan is used to detect the transmitted clock signal and to adjust the synchronism thereby. The page scan is done by the slave apparatus. A network, which is formed by two or more slave apparatuses setting up the connection status in regard to the master apparatus, is a Piconet.
According to the Bluetooth communication method currently in use, a master apparatus can communicate with seven slave apparatuses by connecting the slave apparatuses to achieve an active status in the Piconet. Moreover, to connect a new slave apparatus to the Piconet, the master apparatus terminates the active status with respect to one slave apparatus among the seven slave apparatuses, and performs a communication connection in the active status with the new slave apparatus.
On the other hand, in the Bluetooth communication method, the master apparatus and the slave apparatuses are operated in an active mode for performing a normal communication with the slave apparatuses, and in a hold mode, a sniff mode, and a park mode which enables the communication apparatus to conserve power. The hold mode is a typical mode used when there is no need to send data for a relatively long period. The sniff mode is a mode for transmitting data from a certain time mutually set up between the master apparatus and the slave apparatuses for a predetermined time. The park mode is a mode for performing mutual communication between the master apparatus and the slave apparatus intermittently to allow the slave apparatus to synchronize with the master apparatus, and to acquire conversion to the active mode.
The slave apparatuses, which operate in one of the hold mode, the sniff mode, and the park mode, communicate with the master apparatus for a predetermined time during the operation time of the slave apparatuses operated in the active mode. A data transmission period (hereinbelow, referred to as a ‘sniff period’) of the master apparatus and the slave apparatuses according to the sniff mode is repeatedly generated at a predetermined cycle until the slave apparatuses operated in the sniff mode are converted to the active mode.
At this time, each of the slave apparatuses operated in the sniff mode can have a start time, an allocated time of the sniff period, and a sniff period generation cycle (hereinbelow, referred to as a ‘sniff parameter’), respectively different. The sniff parameter is determined through a link management protocol (LMP) among Bluetooth protocol level structures. The master apparatus of the Piconet including the slave apparatuses (hereinbelow, referred to as ‘a sniff slave apparatus’) operated in the sniff mode allocates the different sniff parameters to the sniff slave apparatuses, and stores the differently allocated sniff parameters.
Accordingly, the master apparatus scheduling the data communication with each of the slave apparatuses needs a memory packet for storing the sniff parameter allocated to the slave apparatuses operated in the sniff mode. Therefore, a number of memory packets should be provided corresponding to at least the number of the slave apparatuses operated in the sniff mode. For example, when seven sniff slave apparatuses are connected with one Piconet, seven memory packets for storing the sniff parameter allocated to the seven sniff slave apparatuses are needed. In addition, seven sniff time sheets (hereinbelow, referred to as a ‘sniff timer’) for notifying the end of the corresponding sniff period to a controller (not shown) of the master apparatus by checking the timer with respect to the sniff period of each of the sniff slave apparatuses are disposed at the master apparatus in the conventional sniff mode.
In the meantime, it will sometimes happen when communicating between the master apparatus and the slave apparatuses through the conventional sniff mode that the sniff period is not allocated to the corresponding sniff slave apparatuses due to a cyclic operation having a higher priority level than the sniff slave apparatuses. The inquiry, the inquiry scan, the page, and the page scan, which are performed by the master apparatus and the slave apparatuses in the Piconet, are such cyclic operations. A supervision timeout rule, which stops the operation needed for the communication connection when a predetermined time set up for communication connection has passed, is applied in the Bluetooth communication method. Accordingly, when the operation, which is needed for the communication connection during the sniff period allocated between the master apparatus and the slave apparatuses, is not supported, the communication connection between the master apparatus and the slave apparatuses fails.
As an example of the communication apparatus utilizing the Bluetooth communication method is a personal portable terminal. Thus, memory packets corresponding to the number of the personal portable terminals operated in the sniff mode should be provided in each of the personal portable terminals. But it is not desirable to provide such memory packets, because this makes it difficult to reduce the size of the product and causes an increase in production costs. Moreover, since the master apparatus consecutively performs the data communication through the sniff parameters stored in each of the memory packets, the scheduling time for the data communication is increased.
The scheduling time for the data communication of the master apparatus is increased, since the master apparatus should allocate the sniff period in regard to each of the sniff slave apparatuses after finding the period not having a cyclic active operation when there is the cyclic active operation performed by the Piconet master apparatus. | {
"pile_set_name": "USPTO Backgrounds"
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The present invention is related to filters suitable for filtering electronic signals, and particularly, AC noise from a DC signal. More specifically, the present invention is related to multi-layered ceramic filters.
Filtering of electronic signals is a widely practiced art typically practiced with filters such as discoidal filters, Pi filters, T filters, LC filters and the like. In general, the type of filter is chosen based on the filtration needs and one of the most common needs is to filter AC noise from DC filters.
Discoidal filters are commonly used where the discoidal filter is placed on the input line and contacted to ground. Placement of the filter is typically a manual operation which is not readily automated thereby significantly increasing the cost of devices containing discoidal filters. In the most demanding applications, such as on the leads of medical implantable devices, the leads must be hermetically sealed, typically in a can, and the can is grounded.
Surface mount filters are available which have some advantages over discoidal filters. Surface mount filters are typically 4 terminal capacitors with input and output terminals perpendicular to each other. This design dictates the relative location of the ground and signal traces which places a constraint on the circuit designer. The perpendicular design also complicates efforts to miniaturize the overall circuit size. As the components become smaller the distance between the signal and ground must be decreased to accommodate the filter terminations. Unfortunately, this increases the potential of arcing, particularly, in high voltage applications. The perpendicular orientation also makes the use of slotted boards impractical and radiation interference mitigation is not typically available.
Pi, T, and LC filters are widely used in either feed-through or surface mount configurations. The surface mount filters are preferred over feed-through when considering further miniaturization even though the radiation interference is superior in the feed-through configurations. The surface mount configurations comprise a magnetic inductor and a ceramic filter and integrating these components is a significant challenge. The magnetic inductor is typically ferrite or ferromagnetic materials which are not compatible with the materials used in multi-layered ceramic capacitors due to the sintering requirements of ceramic.
There has been an ongoing desire for a filter which is small in dimension yet which does not increase complexity in circuit design. There has also been an ongoing desire for a filter which is easily manufactured, is preferably surface mountable or imbeddable, and which can be adapted to various circuit requirements. | {
"pile_set_name": "USPTO Backgrounds"
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This invention relates generally to a corrosivity sensor and a method for its manufacture, and more particularly to a corrosivity sensor which is light enough for aircraft applications and thin enough for use in laminated composites and under coatings, and which is manufactured using masking techniques.
The destructive effects of corrosion are well known and efforts to minimize those effects are ongoing. The non-nuclear naval aircraft-carrier environment is a particularly corrosive one, with sulfur from aircraft-carrier stack gases combining with sea spray to provide a hostile environment which undermines the structural integrity of naval aircraft. Sensors for early detection of the presence of corrosive elements beneath coatings and between the layers of laminated composites would prompt early aircraft maintenance and repair and prevent disaster as well as save time and money.
Galvanic cell-type corrosion probes are currently used to determine the corrosivity of a surrounding medium. One such probe is disclosed in U.S. Pat. No. 4,994,159 to Agarwala et al. This kind of probe has been used on naval aircraft carriers to monitor the corrosivity of the sea environment due to moisture and salt. In operation, a thin film of water from the environment in question, usually in the form of sea spray, contacts the surface of the probe, acting as an electrolyte to complete the galvanic cell formed by two dissimilar metals exposed at the surface. In other words, this film of water acts as a pathway for current flow between the surfaces of the dissimilar metals. The probe is made by embedding within a matrix of insulating material a plurality of plates of alternately anodic and cathodic material, and then exposing the edges of the plates to form the surface. The probe's large size and heavy weight limit its usefulness in applications where space and weight are critical issues, such as on aircraft, and, in particular, within the composite layers of aircraft or on aircraft surfaces to be painted. The large size of this probe also limits its sensitivity because it will only detect the presence of electrolytic films which are large enough in area to bridge the gap between the exposed metals. Additionally, since this probe is made by exposing the edges of flat plates of anodic and cathodic material, the surface pattern thus formed is limited to straight-line strips. The probe is therefore not sensitive to the presence of a film spreading along the insulating surface between strips and parallel thereto.
Masking techniques have been used to manufacture printed circuit boards, but have not been applied to the formation of corrosivity sensors. | {
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1. Field of the Invention
The present, invention relates to a heat exchanger utilized for a heat recovery steam generator in a combined cycle power generation plant or a convection section, and composed of a superheater, a reheater, an economizer and the like, of an outlet portion of a large-sized power generation radiant boiler In such a heat recovery steam generator or convection section, a plurality of tube banks are arranged in rows in a gas passage duct in a direction normal to a gas flow direction, and particularly, one in which the interval of a space between mutually adjoining tube banks is less than eight times the depth of a tube bank disposed on the upstream side and a resonance preventing baffle plate for preventing plural tube bank compound resonance is mounted in each of the tube banks. The depth is a distance from the central axis of the tube arranged on the most upstream side to the central axis of the tube arranged on the most downstream side as described hereinlater.
2. Prior Art
FIG. 6 is a schematic view showing a general structure of a multi-pressure type natural circulation heat recovery steam generator, in which exhaust gas from a gas turbine or the like first flows into a gas passage duct 1 of a natural circulation type heat recovery steam generator and then flows into a SCR (Selective Catalytic Reactor) 4 through a superheater 2 and a high-pressure evaporator 3. In the SCR 4, nitrogen oxide in the exhaust gas is removed. The exhaust gas discharged from the SCR 4 subsequently passes a high-pressure economizer 5, a low-pressure evaporator 6 and a low-pressure economizer 7 and is then subjected to heat exchanging operation with fluid inside the tubes constituting the respective tube banks. After heat exchanging operation, the exhaust gas is discharged into the atmosphere through a chimney, for example. A high-pressure steam and a low-pressure steam generated during the above process is utilized for a driving source of a steam turbine or an auxiliary heat source, for example. In FIG. 6, reference numeral 8 denotes a high-pressure steam drum and numeral 9 denotes a low-pressure steam drum
The respective tube banks of the multi-pressure type natural circulation heat recovery steam generator of the character described above are constituted by a number of tubes 10, as schematically shown in FIGS. 7 and 8, extending in a direction normal to the flow direction of the exhaust gas. The tube arrangement (array) or layout shown in FIG. 7 may be called an in-line array and the tube arrangement or layout shown in FIG. 8 may be called a staggered array. Usually, a tube pitch in the exhaust gas flow direction is represented by P.sub.L and a tube pitch in the direction normal to the gas flow direction is represented by P.sub.T.
The tubes 10 are disposed, as shown in FIG. 9, in an exhaust gas duct 1 which is comprised and separated from an external portion by duct side walls 11, a duct top wall 12 and a duct bottom wall 13.
When the tube banks are utilized for the natural circulation type of exhaust heat recovery steam generator, a finned tube 15 formed by securing a fin 14 to the tube 10, as shown in FIG. 10, may be utilized to enlarge the heat transfer surface area of the tube 10. It is a well known phenomenon that when an external fluid is flown in such tube banks, a vortex called the von Kerman's vortex is periodically generated with back flow in the tubes 10.
Generation frequency f.sub.K (H.sub.z) of such vortex is shown by an equation: EQU f.sub.x =S V/D (1)
(S: the Strouhal number (0.2 in case of a single tube, but different in case of tube banks in accordance with tube array); V: gap flow velocity (flow velocity at an interval between the tubes) (m/s); D: outer diameter (m) of the tube)
While there exists a natural vibration mode determined by the physical properties of the gas between the duct side walls normal to the gas flow direction and the tube axis, and its frequency f.sub.n (H.sub.Z) is represented as follows (in the case of gas, this frequency is called the frequency of standing wave oscillation). EQU f.sub.n =nc/2L (2)
(n=1, 2, 3--; c: speed of sound (m/s); L: width between duct side walls)
In the equation (2), the acoustic velocity c depends on a temperature of the gas of external fluid of the tube.
FIG. 11 shows the primary mode acoustic resonance (the primary mode) on the top side thereof and the secondary mode acoustic resonance (the secondary mode) on the bottom side thereof where a represents a node while b represents a loop.
As the load of the gas turbine changes, the temperature and the flow velocity of the exhaust gas flow from the gas turbine changes, and in a case where there is arranged a tube bank in which the generation frequency f.sub.K of the vortex caused by the back flow of the tube bank substantially accords with the frequency of standing wave oscillation f.sub.n, acoustic vibration, so-called acoustic resonance, is caused between the duct side walls in the direction normal to the fluid flow direction and the axial direction of the tube, which may result in generation of noise harmful to an environmental area, thus being not desirable. Furthermore, in a case where the resonant frequency generation is a value near the natural frequency of the structure, vibration in a direction horizontal to the duct side walls or the tube may be caused.
In order to obviate such defects, in the prior art, as shown in FIG. 12, baffle plates 16 for preventing the generation of the acoustic resonance are inserted in the tube bank 15 by dividing the duct width with a depth substantially equal to the depth of the tube bank. In FIG. 12, the staggered tube array is shown as one example and two baffle plates 16 are inserted to prevent the acoustic resonance phenomenon to the secondary mode from generating.
In this arrangement of the baffle plates 16, acoustic resonance can be prevented in the case of the single tube bank. However, as shown in FIG. 13, for example, in the case of a heat exchanger constituted by a plurality of tube banks, it has been experienced that such acoustic resonance cannot be prevented by merely inserting such baffle plates 16.
FIG. 14 is a graph showing the influence of the numbers of the rows of the tube banks 15 on the acoustic resonance, and in the graph, examples of 6 rows, 4 rows and 3 rows of the tube banks are shown. As can be seen from this graph, in the cases of 6 rows and 4 rows, there are portions at which sound pressures project, thus causing the acoustic resonance, but in the case of 3 rows, no resonance is caused. However, it has been found through experiment that the acoustic resonance is caused when such 3 row tube banks are arranged in plural numbers. Such acoustic resonance caused in the arrangement of a plurality of tube banks is called herein as multibank tubing compound resonance.
FIG. 15 is a graph representing the relationship between the interval of the gap portions of the plural number of tube banks and the sound pressure level raising components upon the generation of the acoustic resonance in a case where two tube banks are arranged, and the sound pressure level raising component is shown by the ordinate at the generation of the acoustic resonance and values obtained by dividing the interval of the gap between the tube banks by the depth of the tube bank arranged on the upstream side are shown by the abscissa. The depth of the tube bank is the distance from the central axis of the tube arranged on the most upstream side to the central axis of the tube arranged on the most downstream side.
As can be seen from FIG. 15, in a case where a value obtained by dividing the gap distance by the depth of the tube bank arranged on the most upstream side is less than 8 times, the raising of the sound pressure level is not observed, but in the case of less than 8 times, the raising of the sound pressure level is observed. In view of this phenomenon, it is considered that phenomenon substantially the same as that in the case of the single tube bank is caused in the case of the gap distance between the upstream side tube bank and the downstream side tube bank being less than 8 times the depth of the upstream side tube bank. In the case of the single tube bank, it has been shown through experiment that the acoustic resonance cannot be prevented in a case where a gap exists between the resonance-preventing baffle plates inserted into the tube bank.
In addition, it has been determined that the noise level will rise when the tube bank depth LA on the upstream side in FIG. 15 is equal and the gap LB of the cavity portion is short, and similarly, that the noise level will also rise when the tube bank depth LA on the upstream side is deep and when the gap LB of the cavity portion is equal.
Further, even in the case of the plural tube banks, these tube bank respectively behave as a single tube bank in the case of the gap or distance between the upstream and downstream side tube banks being more than 8 times of the depth of the upstream side tube bank. | {
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} |
There has been an increasing demand to develop tires with a high level of handling performance, good stability and steering response when changing lanes, avoiding obstacles on the road and cornering. Improved road grip without compromising stability is critical for vehicles traveling at high speed. However, higher tire operating temperatures are encountered at high speeds than are experienced during normal driving and the hot rubber in the tire becomes more pliable which reduces the handling stability of the tire, a so-called “borderline” use of said tire.
A widely adopted method to improve stability, particularly road gripping properties, is to increase the hysteresis loss of tread rubber compositions. A large hysteresis loss during the deformation of tread is used for increasing a friction force between the tread and road surface. However, a significant increase of heat buildup will occur during the running of the tires as the hysteresis loss of the tread rubber becomes large, causing wear resistance of the tread rubber to deteriorate rapidly. On the other hand, it is believed that controllability is significantly influenced by hardness (which is closely related to cornering stiffness of a tire) and breaking strength of rubber compositions. In order to enhance controllability, especially steering response, it is necessary to increase the stiffness of the tire compound in general and the tread in particular, which in most cases results in lower hysteresis loss. Therefore, it is very difficult to achieve both of these desired properties by conventional compounding techniques.
In the past, various attempts have been made to improve driving performance by adding a large amount of a softener or a plasticizer to a rubber composition, or increasing the amount of carbon black, employing carbon black with high surface area, or increasing the amount of sulfur. However, none of these methods are successful in achieving desirable driving characteristics without deteriorating abrasion resistance, especially when running at high speed. Tread rubber compounds containing large amounts of a softener show improved driving performance at low temperatures. However, the inclusion of high levels of softeners results in reduced wear resistance and poor processability. The introduction of a large amount of carbon black with high surface area increases the difficulty of filler dispersion in rubber compounds. Furthermore, increasing the amount of sulfur results in reduced hysteretic loss, but leads to poor traction characteristics.
Rubber compositions containing styrene-butadiene copolymer rubber (SBR) with a high content of bound styrene have been used in tread compositions to increase hysteresis loss. However, such rubber compositions can be inadequate in elastic modulus, especially at high temperatures. Accordingly, polystyrene resins, styrene-butadiene block copolymers, and other hydrocarbon resins have added to such rubber compositions for the purpose of increasing elastic modulus (see U.S. Pat. No. 4,487,892; Japanese Patent No. 5,009,338; European Patent No. 0,117,834A1 and European Patent No. 0,470,693A2). However, the aforementioned materials are essentially soluble in SBR base compositions and act as softeners at elevated temperatures. This results in the hardness and dynamic storage modulus decreasing after substantial heat buildup during high-speed running, which in turn lead to poor controllability and reduced wear resistance.
U.S. Pat. No. 6,469,101 discloses a vulcanizable rubber composition comprising (a) cross-linkable unsaturated chain polymeric base, and (b) from 2 to 30 parts by weight of the polymeric base of at least one polymeric organic compound solid at room temperature and having a glass transition temperature of from 80 to 160° C. and an average molecular weight of from 10,000 to 1,000,000, said polymeric organic compound being substantially insoluble in said polymeric base, wherein the rubber composition has, once vulcanized, a first hysteretic behavior at a first working temperature of a tire having a thread made of the composition and a second hysteretic behavior, which differs from the first hysteretic behavior, at a second working temperature of the tire. The benefits of the incorporation of these organic substances are improved low rolling resistance at 40-70° C. and a high hysteresis loss above 70° C. However, it has been found that the significant increase of hysteresis loss due to phase transition of the included organic substances generates high heat buildup as well. In addition, the spike of hysteresis loss can result in a dramatic change in driving performance and reduced handling performance which is commonly known as “give-up”. Without wishing to be bound by any particular theory, it is believed that the nature of the claimed materials determines that they are unable to maintain the integrity of the phase domains formed while the tread is under high thermomechanical stress. The fusion and flowing of the domains occurs during phase transition, resulting in degradation of controllability. Therefore, the method disclosed to improve controllability and stability is not effective to achieve the total objective being sought.
U.S. Pat. No. 6,127,488 discloses that rubber mixtures prepared from at least one styrene/butadiene rubber gel and at least one rubber which contains double bonds and optionally further fillers and rubber auxiliary substances are in particular suitable for the preparation of vulcanizates having unusually high damping at temperatures of from −20 to +20° C. as well as unusually low damping at temperatures of from 40 to 80° C. The rubber mixtures may therefore be used, for example, to manufacture vehicle tires which grip wet road surfaces and have low rolling resistance.
Japanese Patent No. 2002080642 discloses the inclusion of uncrosslinked or crosslinked polyacrylate or polymethyl methacrylate particles with a mean particle diameter of 1-200 micrometers in tread rubber compositions. The benefits touted as being obtained are improved wet traction, better wear resistance and low heat buildup, without degrading dry traction. Japanese Patent No. 2002080642 also disclosed that particles smaller than 1 micrometer are insufficient to reduce hysteresis loss.
On the other hand, nanoparticles are currently receiving significant interest in rubber compositions. They often provide unique physical properties that differ from those of the bulk material. The higher surface to volume ratio of the nanoparticles provides a better opportunity for chemical and physical interactions with the polymer matrix.
The technical problem underlying the present invention is to provide a solution for obtaining a balance between improved controllability, particularly road grip, and good stability for better overall handling performances at high running speed. As previously mentioned, the hysteretic loss of the tread rubber should be large to obtain high gripping force (traction characteristics) between the tread and road surface. High-speed handling performance closely correlates to the stability of the hysteresis loss. Generally, the addition of high Tg material to boost hysteresis loss at high temperature ranges fails to maintain the stability, as the hysteresis loss undergoes sudden change with the phase transition. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention relates to an LED and, more particularly, to an LED that provides better light-mixing effect by stacking chips.
2. Description of Related Art
A conventional LED utilizes blue light to excite a fluorochrome material to cause the fluorochrome material to emit yellow light, which is mixed with the blue light to generate white light. Alternatively, the conventional LED utilizes a parallel blue chip and yellow chip (shown in FIG. 5 and FIG. 6) to emit the white light. The blue chip 93 and the yellow chip 94 are stuck on the conductive supporting frame 91 of the LED 9 by conductive paste 92, and the electrical power supplied by the conductive frame 91 is used to make the blue chip 93 emit the blue light and the yellow chip 94 to emit yellow light. By controlling the electrical current and voltage, the LED 9 with the characteristic of a single wavelength can make the blue light and yellow light diffuse and mix to provide white light.
However, the LED 9, which has the parallel chip 93 and chip 94, has a problem in mixing the lights, and also has a color fleck problem. The reason is that the distance D between the parallel chip 93 and chip 94 causes the LED to display different colors on two sides of the LED, the blue LED chip 93 side showing blue light and the yellow due to difficulties in processing that the distance D between the chip 93 and the chip 94 cannot be made closer or the chips will be short-circuited and leaking current problems will result, which causes the additional problem of decreasing the yield.
The main objective of the present invention is to solve the aforesaid problems and to provide a stacked, light-mixing LED in which by mixing two lights with different wavelengths in the visible light spectrum area, excited and emitted from a first chip and a second chip, and by controlling electrical current and voltage, the two lights excited from the first chip and the second chip can be mixed into another wavelength of light in the visible light spectrum area, such as the white light, to provide a better symmetric light-mixing effect and avoid a visible color difference.
Another objective of the present invention is to provide a stacked, light-mixing LED without the problem of short circuits and leaking current by stacking the first chip and the second chip. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention relates to novel compounds possessing an antiviral activity, in detail polycyclic carbamoylpyridone derivatives possessing an inhibitory activity against HIV integrase and a pharmaceutical composition containing the same, especially an anti-HIV agent.
2. Description of Related Art
Among viruses, human immunodeficiency virus (HIV), a kind of retrovirus, is known to cause acquired immunodeficiency syndrome (AIDS). The therapeutic agent for AIDS is mainly selected from a group of reverse transcriptase inhibitors (e.g., AZT, 3TC) and protease inhibitors (e.g., Indinavir), but they are proved to be accompanied by side effects such as nephropathy and the emergence of resistant viruses. Thus, the development of anti-HIV agents having the other mechanism of action has been desired.
On the other hand, a combination therapy is reported to be efficient in treatment for AIDS because of the frequent emergence of the resistant mutant. Reverse transcriptase inhibitors and protease inhibitors are clinically used as an anti-HIV agent, however agents having the same mechanism of action often exhibit cross-resistance or only an additional activity. Therefore, anti-HIV agents having the other mechanism of action are desired.
Under the circumstances above, an HIV integrase inhibitor has been focused on as an anti-HIV agent having a novel mechanism of action (Ref: Patent Documents 1 and 2). As an anti-HIV agent having such a mechanism of action, known are carbamoyl-substituted hydroxypyrimidinone derivative (Ref: Patent Documents 3 and 4) and carbamoyl-substituted hydroxypyrrolidione derivative (Ref: Patent Document 5). Further, a patent application concerning carbamoyl-substituted hydroxypyridone derivative has been filed (Ref: Patent Document 6, Example 8).
Other known carbamoylpyridone derivatives include 5-alkoxypyridine-3-carboxamide derivatives and γ-pyrone-3-carboxamide derivatives, which are a plant growth inhibitor or herbicide (Ref: Patent Documents 7-9).
Other HIV integrase inhibitors include N-containing condensed cyclic compounds (Ref: Patent Document 10). [Patent Document 1]WO03/0166275 [Patent Document 2]WO2004/024693 [Patent Document 3]WO03/035076 [Patent Document 4]WO03/035076 [Patent Document 5]WO2004/004657 [Patent Document 6]JP Patent Application 2003-32772 [Patent Document 7]JP Patent Publication 1990-108668 [Patent Document 8]JP Patent Publication 1990-108683 [Patent Document 9]JP Patent Publication 1990-96506 [Patent Document 10]WO2005/016927 | {
"pile_set_name": "USPTO Backgrounds"
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The present invention relates to musical instrument training devices, particularly for stringed instruments and more particularly to an improved fret board training device that includes a matrix of thin lights displayed within the fret board, consisting of a light matrix of electroluminescent flat panel displays which are viewable from a wide angle and under ambient lighting conditions wherein the electroluminescent display (or "ELD") uses a layer of phosphor material and electrode layers with the electrodes supplying an electric field across the phosphor layer.
There are a number of different stringed instruments which have a larger sound box or body with a long narrow neck attached thereto and include a plurality of, for example, 6-12 strings and a number of frets or transverse raised ribs across the neck at regularly spaced intervals. Such instruments are, for example, the guitar, banjo, and the like.
The guitar is typically played by depressing one or more of the strings at certain locations between the frets to shorten the string and thus produce various sounds that are pleasing to the listener. Thus, a user must be able to visually locate a particular and precise fret and string location on the instrument and correctly depress that string at that fret position to produce a particular musical chord or note.
Learning to play the guitar means learning the particular locations for strings and frets as well as an ability to quickly and easily depress the proper string location. The guitar is unmarked with any indicia that would be a clue to the student, thus the learning process is difficult without some visual aid.
One solution to this problem has been to provide a booklet having a diagram corresponding to the guitar chord positions so that the student can look at the book and then visually place his or her fingers at the particular location on the instrument that corresponds to a particular chord or note. This particular practice of teaching is awkward and cumbersome because the student must repeatedly change the position of his head in order to look at either the guitar or the booklet having the instructions. This problem has been discussed in previous U.S. patents, for example, U.S. Pat. No. 4,286,495 issued to John Roof and entitled "Musical Instrument Training Device." The Roof '495 patent offers a possible solution to the above-described problems by providing an electrical device which helps train a student to play a stringed instrument and includes a group of visual indicators mounted on the neck of a fret board and each indicator being immediately beneath and in registry with a particular string and fret of the instrument so as to identify therewith. The Roof '495 patent further provides a second group or plurality of visual indicators mounted on the fret board adjacent the sounding hole in spaced relationship to the first plurality of visual indicators and each one is associated with a particular string to be strummed for a particular musical chord. Switches are provided for selection of musical chords and are operably connected to a diode matrix for energizing selected ones of the visual indicators in the first and second groups whereby the energized visual indicator pattern of the first group represents finger placement loctions along the neck of the fret board for a selected musical chord and the energized visual indicator pattern or the second group represents appropriate strings to be strummed associated with the selected musical chord.
The Roof '495 patent uses light emitting diodes or LEDs which cannot be visualized unless the line of sight is at or very close to a line perpendicular to the plane of the viewing surface. This is a particular problem with guitar players because the guitar is usually placed against the body of the musician. The front surface of the guitar as well as the front face of the fret board is directed away from the musician as well as away from the musician's eyes. Thus, normally the musician must bend over only slightly in order to see the fret board. Nonetheless, the fret board is normally viewed at wide angles to an imaginary line perpendicular to the plane of the viewing surface (e.g., 60-80 degrees). This necessitates a total accessible viewing angle up to 160 degrees. Otherwise, the guitar player would need to lay the guitar virtually flat against his or her lap or against a table in order to see the light display which would be an uncomfortable and unnatural position considerably hindering the playability of the instrument.
Several other patents have been issued which are directed to the problem of a visual device for teaching the playing of a musical stringed instrument. Examples of other patents include the Pipkin U.S. Pat. Nos. 2,788,699, the Sapinski 3,854,370, the Johnson 3,978,757, the Gilbert 3,943,815, the Ratanangsu 4,080,867, and the Habicht 4,545,281.
These patents do not solve the problem of providing an easily viewable matrix of thin lights displayed within the fret board of a guitar and having a wide angle viewing area under ambient lighting conditions.
Electroluminescent displays (ELDs) are commercially available. ELDs are discussed, for example, in the March 1985 issue of BYTE magazine with appended bibliography and references. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field
Embodiments of the present disclosure relate to a robot cleaner which includes a dust box separably mounted to a body, performs a cleaning operation while traveling autonomously, and docks with an automatic exhaust station to automatically exhaust dust from the dust box to the automatic exhaust station.
2. Description of the Related Art
A robot cleaner includes various sensors, a driving unit, and a cleaning unit to perform cleaning while traveling autonomously.
Generally, in such a robot cleaner, a separable dust box is mounted to a body of the robot cleaner. Accordingly, the user can exhaust dust collected in the dust box after separating the dust box from the body. However, when the separated dust box is shaken or turned over, the dust collected in the dust box may be unintentionally discharged.
To this end, it may be necessary to provide a structure to allow an inlet of the dust box to be opened during a cleaning operation while maintaining the inlet of the dust box in a closed state when the dust box is separated from the body.
Meanwhile, there is a system enabling the robot cleaner to dock with an automatic exhaust station so as to automatically exhaust dust from the dust box to the automatic exhaust station. In such a system, however, it may be difficult to discharge heavy items (including coins and other heavy granules) from the dust box because the heavy items may be trapped by a stepped structure formed at the inlet of the dust box. | {
"pile_set_name": "USPTO Backgrounds"
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The manufacture of advanced semiconductor devices entails the integration and sequencing of many unit processing steps, with potential new material and process developments. The precise sequencing and integration of the unit processing steps enables the formation of functional devices meeting desired performance metrics such as power efficiency, signal propagation, and reliability.
As part of the discovery, optimization and qualification of each unit process, it is desirable to be able to i) test different materials, ii) test different processing conditions within each unit process module, iii) test different sequencing and integration of processing modules within an integrated processing tool, iv) test different sequencing of processing tools in executing different process sequence integration flows, and combinations thereof in the manufacture of devices such as integrated circuits. In particular, there is a need to be able to test i) more than one material, ii) more than one processing condition, iii) more than one sequence of processing conditions, iv) more than one process sequence integration flow, and combinations thereof, collectively known as “combinatorial process sequence integration”, on a single monolithic substrate without the need of consuming the equivalent number of monolithic substrates per material(s), processing condition(s), sequence(s) of processing conditions, sequence(s) of processes, and combinations thereof. This can greatly improve both the speed and reduce the costs associated with the discovery, implementation, optimization, and qualification of material(s), process(es), and process integration sequence(s) required for manufacturing.
Systems and methods for High Productivity Combinatorial (HPC) processing are described in U.S. Pat. No. 7,544,574 filed on Feb. 10, 2006, U.S. Pat. No. 7,824,935 filed on Jul. 2, 2008, U.S. Pat. No. 7,871,928 filed on May 4, 2009, U.S. Pat. No. 7,902,063 filed on Feb. 10, 2006, and U.S. Pat. No. 7,947,531 filed on Aug. 28, 2009 which are all herein incorporated by reference. Systems and methods for HPC processing are further described in U.S. patent application Ser. No. 11/352,077 filed on Feb. 10, 2006, claiming priority from Oct. 15, 2005, U.S. patent application Ser. No. 11/419,174 filed on May 18, 2006, claiming priority from Oct. 15, 2005, U.S. patent application Ser. No. 11/674,132 filed on Feb. 12, 2007, claiming priority from Oct. 15, 2005, and U.S. patent application Ser. No. 11/674,137 filed on Feb. 12, 2007, claiming priority from Oct. 15, 2005 which are all herein incorporated by reference.
HPC processing techniques have been used in wet chemical processing such as etching and cleaning. HPC processing techniques have also been used in deposition processes such as physical vapor deposition (PVD), atomic layer deposition (ALD), and chemical vapor deposition (CVD).
In standard HPC systems, multiple site isolated regions on a substrate surface can be formed by sealing different regions of the surface, isolating the surface regions from each other. The surface sealing can generate particles, which requires subsequent substrate cleaning. Therefore there is a need for non-contact isolation of surface regions on a substrate surface. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
The present invention relates to a technique for mapping asynchronous fixed-length cells such as ATM cells, etc. onto an existing synchronous digital interface.
2. Description of the Related Art
Synchronous digital private lines which are conventionally connected to an enterprise have been increasingly shifted to ATM (Asynchronous Transfer Mode) lines by using TDMs (Time Division Multiplexers), etc.
In such a case, a TDM arranged in an enterprise is replaced with an ATM switch, to which a PBX (Private Branch exchange), an ATM terminal, etc. inside the enterprise are connected.
Since communications are asynchronously made and communications channels are not always busy with the ATM system, the effect of multiplexing is significant and multimedia data, etc. can be efficiently transmitted.
An ATM line has the transmission rate of at least 155 Mbps. If one certain enterprise attempts to newly adopt ATM lines instead of synchronous digital private lines in a current state, it requires a lot more cost.
Therefore, there is a conventional technique for mapping ATM cells onto a synchronous digital interface format as a technique for promoting the shift from a synchronous digital communication to an ATM communication. As typical techniques, the techniques stipulated by the ITU-T G.804, the ATM Forum AF-PHY-0016.000, the UNI version 3.1, etc. are known.
Use of such techniques allows a TDM, etc. arranged in an enterprise to be replaced with an ATM switch without changing an existing synchronous digital interface on a network side and an existing PBX and terminal equipment, etc. inside the enterprise.
More specifically, the ATM switches to which the above described techniques are applied are arranged at both ends of a private synchronous private line. By connecting existing PBXs and terminals in an enterprise to the ATM switches at the beginning of the shift, ATM cells are mapped onto a synchronous digital interface and transmitted by a communication between the ATM switches at both of the ends without user's awareness of the shift from the TDM devices, etc. to the ATM switch. At a later stage of the shift, ATM terminals, etc. are newly connected to the ATM switches, so that the user can smoothly and gradually shift the existing terminals, etc. to the ATM terminals, etc.
As a current contract form of the synchronous digital private line, not an entire bandwidth, but only a bandwidth according to an amount required by traffic can be contracted. In this case, a user will use a predetermined number of time slots among the time slots allocated to a synchronous digital private line via a TDM, etc.
With the above described conventional technique for mapping ATM cells onto a synchronous digital interface, however, the ATM cells are mapped onto an entire bandwidth (all time slots) of the physical line configuring the synchronous digital interface. Therefore, this mapping technique has the problem of being unable to be applied to the implementation in which only part of the bandwidth (some of the time slots) of the synchronous digital private line is used. | {
"pile_set_name": "USPTO Backgrounds"
} |
1. Field of the Invention
Embodiments of the present invention relate to a semiconductor device and a method for forming the same, and more particularly to a semiconductor device including a contact plug and a method for forming the same.
2. Background of the Invention
In a manufacturing process of a semiconductor device, it is necessary to form a metal contact plug for electrically coupling a predetermined lower metal line to an upper metal line. However, in recent times, as the semiconductor device is highly integrated and super-miniaturized, it is necessary to more precisely form a metal contact plug for interconnection between metal lines. In addition, as the demand of electrical characteristics and operation speed of the semiconductor device are further increased, a metal contact plug is required to have a more precise structure, lower resistance, and higher reliability.
Generally, although tungsten (W) and aluminum (Al) are basically used to form a metal line and a metal contact plug, the tungsten (W) and the aluminum (Al) may encounter problems caused by electro-migration or stress-migration. In order to solve the problem, a new method for replacing tungsten (W) or aluminum (Al) with copper (Cu) has been proposed.
Copper (Cu) is generally used as a metal line to increase the operating speed of the semiconductor device. Since copper has difficulty in an etching process, the copper (Cu) is formed using a dual damascene process. In the dual damascene process, an etch stop layer and an interlayer insulating layer are laminated in the form of multiple layers and are etched to form a contact hole and a trench, such that a diffusion barrier and a seed layer are formed over the entire structure including the contact hole and the trench. Subsequently, a copper (Cu) line is deposited by an electroplating process and is polished by a chemical mechanical polishing (CMP) process, such that the contact plug and the copper (Cu) line can be simultaneously formed by the dual damascene process.
As the semiconductor device is highly integrated, the difficulty in forming a minute content hole is also increasing. Although a minute contact hole can be properly formed, its contact resistance is increased due to a shortened distance between the neighboring metal lines. As a result, a defect due to high resistance may occur in the semiconductor device, which makes it difficult for the dual damascene process to be applied for a low-power semiconductor device. Further, when the dual damascene process is applied to the manufacturing process of the semiconductor device with a narrowly scaled down contact hole, it is probable that the contact hole is not fully filled up by conductive material and thus creates a void in the contact plug.
If copper (Cu) fills up the contact hole, copper atoms may diffuse into an neighboring device element to cause contamination. In order to prevent the other device elements from being contaminated, a barrier metal layer is generally formed over the surface of the contact hole. However, due to miniaturization, the barrier metal layer cannot be formed thick enough to prevent copper migration. | {
"pile_set_name": "USPTO Backgrounds"
} |
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