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Fishing boats and vessels are often equipped with a trolling motor for providing a relatively small amount of thrust to slowly and quietly propel the boat or vessel while the operator is fishing. Most outboard trolling motors are typically powered by a battery and are mounted to either the bow or the stem of the boat or vessel. Bow mounted trolling motors are generally mounted to the deck at the bow of a boat by means of a base plate screwed or otherwise fastened to the bow of the boat and a chassis, also known as a frame or bracket, coupled to the trolling motor and configured to mate with the base plate.
Such trolling motors may be configured to pivot between a deployed or use position and a stowed or non-use position. However, such known mounting arrangements for trolling motors may present inconvenient or disadvantageous features in application or use, such as relative difficulty to use (e.g., effort and vigilance to stow or deploy). Also, such known arrangements may present inconvenient or undesirable operation such as high impact or velocity deployment of the trolling motor if it is dropped onto the water, which may cause a potential for an unpleasant or startling noise, or for damage to the trolling motor or watercraft.
As can be appreciated, trolling motors include several movable parts that may be susceptible to failure if the trolling motor is dropped, bumped or otherwise knocked around. Damage to a trolling motor is commonly inflicted while an operator is attempting to move the trolling motor from a stowed position to a deployed position. Often this movement is rather abrupt since the weight of the trolling motor increases the acceleration of the trolling motor into the water. Such an abrupt movement may cause unnecessary damage or wear to the trolling motor as the trolling motor impacts the water and/or any other object.
Accordingly, it would be advantageous to provide a trolling motor mounting system that has a compact design and can be readily mounted to a boat or vessel. It would also be advantageous to provide a trolling motor mount system with a mechanism for moving the trolling motor between the deployed position and the stowed position that is more convenient to use. If would further be advantageous to provide a trolling motor mount system that is configured to control the velocity that the trolling motor can be raised and/or lowered. It would further be advantageous to provide a trolling motor mount system that is configured to assist in moving the trolling motor between the deployed and use positions. It would further be advantageous to provide a trolling motor system that is configured to be more convenient to clean, keep clean, and maintain. It would be desirable to provide for a trolling motor system having one or more of these or other advantageous features.
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C5a is cleaved from C5 upon complement activation. Among the complement activation products, C5a is one of the most potent inflammatory peptides, with a broad spectrum of functions (Guo and Ward 2005). C5a is a glycoprotein present in the blood of healthy humans with a molecular weight of 11.2 kDa. The polypeptide portion of C5a contains 74 amino acids, accounting for a molecular weight of 8.2 kDa while the carbohydrate portion accounts for approximately 3 kDa. C5a exerts its effects through the high-affinity C5a receptors (C5aR and C5L2) (Ward 2009). C5aR belongs to the rhodopsin-type family of G-protein-coupled receptors with seven transmembrane segments; C5L2 is similar but is not G-protein-coupled. It is currently believed that C5a exerts its biological functions primarily through C5a-05aR interaction, as few biological responses have been found for C5a-C5L2 interaction. C5aR is widely expressed on myeloid cells including neutrophils, eosinophils, basophils, and monocytes, and nonmyeloid cells in many organs, especially in the lung and liver, indicative of the importance of C5a/C5aR signaling. C5a has a variety of biological functions (Guo and Ward 2005). C5a is a strong chemoattractant for neutrophils and also has chemotactic activity for monocytes and macrophages. C5a causes an oxidative burst (O2 consumption) in neutrophils and enhances phagocytosis and release of granular enzymes. C5a has also been found to be a vasodilator. C5a has been shown to be involved in modulation of cytokine expression from various cell types, to enhance expression of adhesion molecules on neutrophils. It is found that C5a becomes highly detrimental when it is overly produced in the disease settings, as it is a strong inducer and enhancer for inflammatory responses functioning in the up-stream of the inflammatory reaction chain. High doses of C5a can lead to nonspecific chemotactic “desensitization” for neutrophils, thereby causing broad dysfunction (Huber-Lang et al. 2001a).
C5a has been reported to exert numerous pro-inflammatory responses, and has been reported to be harmful during sepsis. Inhibition of C5a or of the C5a receptor (C5aR) by antibodies has been demonstrated to dramatically improve survival in various sepsis models in mice and rats (Czermak et al. 1999; Guo et al. 2000; Huber-Lang et al. 2001b; Riedemann et al. 2002a). In addition, various reports have demonstrated harmful effects of C5a for intact innate immune- and organ functions during experimental sepsis (Guo et al. 2000; Guo et al. 2002; Huber-Lang et al. 2001a; Huber-Lang et al. 2002; Laudes et al. 2002; Riedemann et al. 2003; Riedemann et al. 2004a; Riedemann et al. 2004b). C5a acts as an anaphylatoxin and has been reported to exert numerous pro-inflammatory effects. In human, sepsis high levels of C5a have been reported to be associated with significantly worsened outcome in various studies (Bengtson and Heideman 1988; Nakae et al. 1994; Nakae et al. 1996).
In the experimental setting of sepsis, exposure of neutrophils to C5a can lead to neutrophil dysfunction and paralysis of signaling pathways, leading to defective assembly of NADPH oxidase, paralysis of MAPK signaling cascades, a greatly depressed oxidative burst, phagocytosis and chemotaxis (Guo et al. 2006a; Huber-Lang et al. 2002). Thymocyte apoptosis and delayed neutrophil apoptosis are two important pathogenic events for sepsis development, which are dependent on the presence of C5a (Guo et al. 2000; Guo et al. 2006b). During experimental sepsis, C5a up-regulates β2 integrin expression on neutrophils to promote cell migration into organs (Guo et al. 2002), one of the major causes for multi-organ failure (MOF). It is also found that C5a is attributable to the activation of the coagulation pathway that occurs in the experimental sepsis (Laudes et al. 2002). C5a stimulates the synthesis and release from human leukocytes of pro-inflammatory cytokines such as TNF-α, IL-β, IL-6, IL-8, and macrophage migration inhibitory factor (MIF) (Hopken et al. 1996; Riedemann et al. 2004a; Strieter et al. 1992). C5a produces a strong synergistic effect with LPS in production of TNF-α, macrophage inflammatory protein (MIP)-2, cytokine-induced neutrophil chemoattractant (CINC)-1, and IL-1β in alveolar epithelial cells (Riedemann et al. 2002b; Rittirsch et al. 2008). Given that complement activation is an event occurring during the onset of sepsis, C5a may come into play before emergence of the “inflammatory cytokine storm”. It appears that C5a plays a key role in orchestrating the performance of the cytokine network and the formation of systemic inflammatory response syndrome (SIRS). Blockade of C5a in the setting of experimental sepsis dramatically attenuates MOF and SIRS. Widespread up-regulation of C5aR expression occurs during onset of sepsis, and blockade of C5a/C5aR interaction by anti-05a, or anti-05aR antibodies, or C5aR antagonists renders highly protective effects in rodent models of sepsis (Czermak et al. 1999; Huber-Lang et al. 2001b; Riedemann et al. 2002a).
In addition to the sepsis indication, blockade of C5a has also been proven to be protective in many other models of inflammation such as ischemia/reperfusion injury, renal disease, graft rejection, malaria, rheumatoid arthritis, infectious bowel disease, inflammatory lung disease, lupus-like auto-immune diseases, neurodegenerative disease, etc. in various species as partially reviewed under Klos A. et al (Klos et al. 2009) and Allegretti M. et al (Allegretti et al. 2005). Moreover, it has been recently discovered that blockade of C5a has shown a strong therapeutic benefit in a tumor model in mice (Markiewski et al. 2008).
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The present invention relates to energy absorbing vehicle bumper assemblies.
It is conventionally known to assemble a vehicle bumper which includes an impact beam and an energy absorbing medium which are covered by a fascia. With such an assembly the energy absorbing medium is secured to the impact beam prior to assembly to the vehicle. It is also known to incorporate the usual impact beam and energy absorber into one blow molded plastic part. However, such an assembly tends to be somewhat heavy and costly.
Conventional blow molded bumper beams generally incorporate a series of fastening studs which are molded into the plastic part to assist in assembly to the vehicle. It has been found however, that studs tend to be pulled out of the molded plastic part under an unacceptably low tensile load. Previous attempts to solve this problem have integrated a stud plate or stay into the molded beam to which the studs are welded. This stay however, adds undesirable weight and cost to the bumper beam assembly.
It is preferred that a bumper beam be fabricated such as to minimize costs and weight while performing acceptably when assembled to a vehicle.
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Manufacturers have developed various techniques for fabricating microstructures that have small feature sizes on substrates. Typically the microstructures form one of more layers of an electronic circuit. Examples of these structures include light-emitting diode (LED) display devices, polymer light-emitting diode (PLED) display devices, liquid crystal display (LCD) devices, printed circuit boards and the like. Most of these manufacturing techniques are relatively expensive to implement and require high production quantities to amortize the cost of the fabrication equipment.
One technique for forming microstructures oh a substrate includes screen printing. During screen printing, a fine mesh screen is positioned on the substrate. Fluid material is deposited through the screen and onto the substrate in a pattern defined by the screen. Screen printing requires contact between the screen and the substrate. Contact also occurs between the screen and the fluid material, which contaminates both the substrate and the fluid material.
While screen printing is suitable for forming some microstructures, many manufacturing processes must be contamination-free to produce operational devices. Therefore, screen printing is not a viable option for the manufacture of certain microstructures. For example, polymer light-emitting diode (PLED) display devices require a contamination-free manufacturing process.
Certain polymeric substances can be used in diodes to generate visible light of different wavelengths. Using these polymers, display devices having pixels with sub-components of red, green, and blue can be created. PLED fluid materials enable full-spectrum color displays and require very little power to emit a substantial amount of light. It is expected that PLED displays will be used in the future for various applications, including televisions, computer monitors, PDAs, other handheld computing devices, cellular phones, and the like. It is also expected that PLED technology will be used for manufacturing light-emitting panels that provide ambient lighting for office, storage, and living spaces. One obstacle to the widespread use of PLED display devices is the difficulty encountered to manufacture PLED display devices.
Photolithography is another manufacturing technique that is used to manufacture microstructures on substrates. Photolithography is also not compatible with PLED display devices. Manufacturing processes using photolithography generally involve the deposition of a photoresist material onto a substrate. The photoresist material is cured by exposure to light. A patterned mask is used to selectively apply light to the photo resist material. Photoresist that is exposed to the light is cured and unexposed portions are not cured. The uncured portions are removed from the substrate.
An underlying surface of the substrate is exposed through the removed photoresist layer. The cured portions of the photoresist layer remain on the substrate. Another material is then deposited onto the substrate through the opened pattern on the photoresist layer, followed by the removal of the cured portion of the photoresist layer.
Photolithography has been used successfully to manufacture many microstructures such as traces on circuit boards. However, photolithography contaminates the substrate and the material formed on the substrate. Photolithography is not compatible with the manufacture of PLED displays because the photoresist contaminates the PLED polymers. In addition, photolithography involves multiple steps for applying and processing the photoresist material. The cost of the photolithography process can be prohibitive when relatively small quantities are to be fabricated.
Spin coating has also been used to form microstructures. Spin coating involves rotating a substrate while depositing fluid material at the center of the substrate. The rotational motion of the substrate causes the fluid material to spread evenly across the surface of the substrate. Spin coating is also an expensive process because a majority of the fluid material does not remain on the substrate. In addition, the size of the substrate is limited by the spin coating process to less than approximately 12″, which makes spin coating unsuitable for larger devices such as PLED televisions.
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Currently, most smart TVs support that multiple display windows display different contents (e.g. Picture In Picture (PIP) or Picture Out Picture (POP)) in their screens, when switching between a main display window and a sub-display window, the TV mainly has the following switching methods:
In the case that two different TV programs are received from the same program source (e.g. all parsed from the TV program stream of the broadcast system), before switching, the TV parses, from the received TV program streams, the TV programs of the corresponding channels displayed in the main display window and the sub-display window respectively, and displays the respective contents through the main display window and the sub-display window, when the switching is executed, the TV operates the two parsed contents displayed by the windows of each other. Currently, in the case that two different programs are received from different program sources, such as receiving the TV program stream from the broadcast system and also receiving the programs from the server of the Internet, before switching, the TV parses, from the received TV program signals, the program displayed in the main window, and receives, from the server, the program data displayed in the sub-display window, and then displays the respective contents through the main display window and the sub-display window. When the switching is executed, the TV controls the two content portions to be displayed using the windows of the other party.
The said switching process of the TV display windows is achieved by the TV device, and it does not need to make any change to the process of receiving signals. For example, the description of China patent application No. CN200880016617 publicizes that the display is capable of receiving one or more TV channels and an independent designated application channel and having at least a first display window and a second display window. The information sent by the designated application channel is displayed on the first display window while simultaneously one of the TV channels is displayed on the second display window, and the information received from the designated application channel is allowed to switch between the first display window and the second display window.
As the first display window and the second display window normally corresponds to the main display window with big size and the sub-display window with small size, and after switching, if the low resolution content displayed in the sub-display window originally is enlarged to be displayed in the main display window, the display quality will be reduced significantly as a result.
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The simplest light-emitting system among luciferases is performed by the luminescence reaction only with a luciferin and molecular oxygen, and a representative light-emitting system utilizes coelenterazine as a light-emitting substrate. Since the luminescence reaction is simple, a reporter assay using the gene has been widely used. Among luciferases used in the light-emitting system that utilizes coelenterazine as a substrate, Oplophorus luciferase, Gaussia luciferase and the like are known as secreted luciferases.
Oplophorus luciferase was isolated from the deep-sea shrimp that is classified in crustaceans and the protein was identified by Shimomura, et al. in 1978 (Non-Patent Document 1). In 2000, Inouye et al. revealed by isolation of the gene that Oplophorus luciferase is a complex composed of 35 kDa protein consisting of 320 amino acid residues and 19 kDa protein consisting of 169 amino acid residues (Patent Document 1, Non-Patent Document 2). It has also been demonstrated by gene expression using Escherichia coli and cultured animal cells that the catalytic domain responsible for the luminescent oxidation of coelenterazine is present in the 19 kDa protein (Patent Document 1, Non-Patent Document 2). When a gene encoding the 19 kDa domain protein is expressed in Escherichia coli, it is expressed as inclusion bodies over 95%. It is reported that the 19 kDa protein is expressed as a soluble form in the Escherichia coli system using the fusion protein with protein A derived ZZ-domain (Non-Patent Document 3). On the other hand, it is shown that cultured animal cells do not secret the 19 kDa protein by their own signal peptide sequence for secretion but the 19 kDa protein have a luminescence activity in the cells (Non-Patent Document 2). In 2012, a method of conventional random mutagenesis was applied to this gene of the 19 kDa domain protein to produce the mutagenized 19 kDa domain gene, which was shown to provide higher activity than that of native 19 kDa protein, named “nanoLuc.” NanoLuc shows the difference of 16 amino acid residues with the native 19 kDa protein, which consists of 169 amino acid residues (KAZ), indicating 90.5% identity (Non-Patent Document 4). However, the essential amino acid residues for luminescence function are not identified and the function of mutated amino acid residues remains unclear. Patent Document 2 discloses the mutated 19 kDa protein including nanoLuc, which shows higher activity than that of native 19 kDa protein.
Coelenterazine, a light-emitting substrate, is also known as a light-emitting substrate for Renilla luciferase of Renilla reniformis or as a source of light emission for the photoprotein aequorin isolated from Aequorea victoria and is a compound having an imidazopyrazinone ring as a core structure. The mechanism of light emission is considered as follows. Molecular oxygen attaches to coelenterazine and the resulting peroxide produces the dioxetanone. Subsequently, decarboxylation proceeds to form the coelenteramide anion at the excited state, which is supposed to be a light emitter. And when the anion relaxes to the ground state, it is considered to produce light emission of blue (λmax=460-490 nm). More than 50 coelenterazine analogues have been synthesized so far and luminescence properties have been investigated by using them as substrates. In particular, Oplophorus luciferase has a broad range of substrate specificity compared to other coelenterazine-type luciferases. It is difficult to find out coelenterazine analogues showing the luminescence activity with at least 5-fold higher than that of coelenterazine (Non-Patent Documents 5-9).
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This invention relates to chemically modifying the surfaces of polymeric materials.
A number of polymers useful in the biomedical field, e.g., for storing, dispensing, handling, or transferring materials such as drugs, proteins, biological macromolecules, and vaccines contain hydroxyl or carboxyl groups (or both) either as end groups or side groups along the polymer chain. Examples of polymers (including elastomers, rubbers, or plastics) having hydroxyl or carboxyl side groups include poly(hydroxyethyl methacrylate) and polyvinyl alcohols. Polymers having hydroxyl or carboxyl end groups include polyesters, polycarbonates, polylactones, polyurethanes, polyacetals, polyethers, silicones, and polyamides (e.g., nylons). In addition, polymers crosslinked using crosslinking agents such as diols and dihydroxy phenols will contain terminal hydroxyl groups.
One problem associated with these polymers is the deposition of materials such as proteins, biological macromolecules, drugs, or vaccines on the surface of the polymer due to hydrogen bonding between the deposited material and surface hydroxyl or carboxyl groups. Such deposition limits the usefulness of these polymers because the adsorbed materials are often very costly. Lim et al., U.S. Pat. No. 4,569,858 describes improving the soil resistance, e.g., to proteins, of a contact lens made from a hydrophilic polymer having surface hydroxyl and carboxyl groups by either treating the lens directly with reagents such as diazoalkanes, dimethylformamide dialkyl acetals, and the reaction product of alkylenediisocyanate and polyethylene glycol monomethyl ether, or by pretreating the lens with a strong base followed by treatment with a relatively high molecular weight acylating agent (e.g., neodecanoyl chloride or pivaloyl chloride).
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This invention relates to a voltage-controlled oscillator.
In general, the oscillation frequency of an oscillator is determined by a resonator and also the equivalent capacitance of a bipolar-transistor circuit connected to the resonator. Thus, the oscillation frequency fluctuates with variations in the equivalent load capacitance.
Part of a Colpitts oscillator using a bipolar transistor can be realized by a semiconductor integrated circuit (IC). In such a Colpitts oscillator IC, a stray capacitance between a transistor collector and an IC substrate being a ground causes a problem. This stray capacitance includes a transistor pn junction capcitance. Thus, the stray capacitance depends on a temperature and a related voltage relative to the IC substrate. The stray capacitance composes a load capacitance connected to a resonator. Therefore, the oscillation frequency of the Colpitts oscillator fluctuates with variations in the temperature and the voltage.
Smaller-size and lower-price voltage-controlled oscillators have been demanded. A good way of satisfying this demand is to form at least part of the voltage-controlled oscillator by a semiconductor integrated circuit.
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Cannabinoids are a group of extracellular signaling molecules that are found in both plants and animals. Signals from these molecules are mediated in animals by two G-protein coupled receptors, Cannnabinoid Receptor 1 (CB1) and Cannabinoid Receptor 2 (CB2). CB1 is expressed most abundantly in the neurons of the CNS but is also present at lower concentrations in a variety of peripheral tissues and cells (Matsuda, L. A. et al. (1990) Nature 346:561-564). In contrast, CB2 is expressed predominantly, although not exclusively, in non-neural tissues, e.g. in hematopoietic cells, endothelial cells, osteoblasts, osteoclasts, the endocrine pancreas, and cancerous cell lines (Munro, S. et al. (1993) Nature 365:61-65; and as reviewed in Pacher, P. et al. (2006) Pharmacol. Rev. 58(3): 389-462). As such, CB1 is believed to be primarily responsible for mediating the psychotropic effects of cannabinoids on the body, whereas CB2 is believed to be primarily responsible for most of their non-neural effects.
The texts of the references cited in this disclosure are herein incorporated by reference in their entireties. In the event that a definition of a term as incorporated by reference differs from the meaning defined herein, then the meaning provided herein is intended.
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The present invention relates to a soot blaster.
Soot blasters are used to blast sooty deposits off hot surfaces, especially off heating surfaces of boilers and the like. They use a tube-shaped lance having one or more outlet nozzles through which a gaseous and/or liquid blasting medium is expelled at high velocity. The lance is turningly inserted into the space to be cleaned, advanced to its leading end position and is then retracted again.
It is customary that the tip of the lance is provided with two opposite nozzles. If so, these perform during the cleaning operation a double-helix movement, the spacing of the helices being equal to half of the selected forward movement per rotation of the lance. The drive elements for the longitudinal and rotary movement during each cleaning incident will always be the same. That is to say that the fluid blasts invariably contact the same areas of the surface being cleaned, which eventually leads to erosion damage to these surfaces.
To avoid this, it is known from German Pat. No. 2,757,981 to so construct the soot blaster that each cleaning incident is begun with the nozzles in a different position. This construction proposes to use two free-wheeling devices between the drive shaft for the longitudinal drive and the drive for the rotary motion. These devices are actuatable in mutually opposite directions and one of them has a predetermined play built into it in direction of rotation of the drive shaft.
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The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
A second screen device (also known as a “companion device”) may be a portable screen-based computing device (for example a smartphone, tablet computer) that allows a content consumer to interact with content (for example shows, movies, music, video games) that is presented by a media device (for example game console, set-top box, digital video player, television). In many cases, the second screen device is synchronized with the content displayed on the media device and displays additional options or data that enhances the user's experience. In typical cases, the second screen device and the media device are located close to each other (for example close enough that the user can view both screens without too much effort) and communicatively coupled over the user's local area network (LAN). As one example, a smartphone can be configured to allow a user to view live tweets or comments related to a program being displayed on their television. As another example, a tablet computer can be synchronized with a game console to display additional data, such as a map or heads-up display. As yet another example, a second screen device can be synchronized with a digital video recorder to select and control media for presentation, essentially replacing the need for a standard remote control.
However, while second screen technology allows multiple devices to work in concert to enhance the user's experience, many uses of this technology also require communication between the pairing and external servers on which the user has an account (for example servers that provide the media content, game servers that allow players to interact online). Thus, to protect the user's communications and devices, security is needed not only between the pair of devices, but also between the devices and the authentication server that binds the pairing to the user's account. This issue can also be made difficult in light of the fact that second screen devices may be more vulnerable to attack than the multimedia devices, as well as the converse. As a result, security for the system may run into Byzantine device failures (untrustworthy devices), as well as other standard attacks such as man-in-the-middle and replay.
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1. Field of the Invention
The present invention relates generally to exercise machines, and more particularly to multi-position weight machines, and still more particularly to a multi-position resistance tube exercise apparatus for mounting on a wall or, alternatively, on a vehicle, that enables a user to achieve a full body workout, including a core workout, principally from a standing position exclusively, though numerous seated exercises are also possible. The apparatus is well-suited for transport and particularly well adapted for installation on a semi-truck cab for use by truck drivers to maintain good body conditioning during long hauls.
2. Background Discussion
Truck drivers are an important part of our workforce, literally keeping our economy rolling. However, the environment in and the conditions under which they work tend to promote poor health. Domestically, under federal law drivers are permitted to drive eleven hours in any 24 hour period, and when team driving, drivers may remain in the truck after a driving shift, thus remaining in the truck essentially around the clock for days at a time. These extremes arise from the competitive demands in this segment of the transportation economy. Drivers, unfortunately, bear the brunt of the demands, and they do so by subjecting their bodies to hardship in the form of remaining inactive for long hours, maintaining a relative fixed and sedentary (sitting) position for long hours, of subtly (sometimes not so subtly) vibrating vital organs from road vibrations, staying in close proximity to engine noise, sleeping irregular hours, eating low nutritional value fast foods in truck stops and diners, and so forth. The range of adverse health effects include tinnitus, neck pain, low back pain, digestive tract ulcers, obesity, hypertension, back injuries, sleep apnea, headaches, vision problems, and hemorrhoids, among others. Drivers also have high rates of smoking.
Truck drivers do not have easy access to gym facilities for engaging in any kind of a regular workout regimen. What they need is apparatus that provides a convenience, economical, and easy to use system that provides the means to obtain a whole body workout. Free weights are impractical and take up too much room. Weighted plate machines are similarly cumbersome and impractical. Multiposition machines off some promise, but most are currently packaged in an overall system adapted for home use, with ample space for both actual use and storage.
Resistance tube exercise machines also offer some promise. Multi-position resistance tube exercise machines are known. A number of major exercise machine manufacturers make and sell commercial and residential machines either dedicated to particular exercises or a small group of exercises designed to exercise small groups of muscles or, alternatively, machines designed to enable a user to perform a number of exercises and to address a wide range of muscles and muscle groups. Traditionally, the systems have employed moveable weight stacks incorporated into compact frame structures with attachments to the stack from multiple directions and at multiple positions and angles through cable and pulley assemblies so as to provide a user with numerous exercise options.
However, weight stack systems have several liabilities. First, comprehensive systems are very expensive. Second, they require the allocation of significant floor space. Third, they provide an imperfect, and some say inherently flawed, simulation of the kinds of load placed on muscles in natural and competitive athletic environments. Fourth, the load borne by the user tends to vary dramatically through a full range of motion during any given exercise. Fifth, they can present a risk of injury. Sixth, they are not adapted for transport in, and use on and around vehicles. And finally, by their very nature they are, for all practical purposes, permanent fixtures. Increasingly physiatrists, physical therapists, gyms, schools, and especially individuals wishing to experience a full body workout, are relying on resistance tubes and bands as the means to place a load on specific muscles and muscle groups for resistance exercise. For the most part, such “systems” amount to little more than one or more resistance tubes adapted for connection to walls, doors, furniture, and the like, to provide a simple way of achieving multiple angles from which resistance is offered. However, such systems rely on reliable and safe connections in the environment and they are limited by the size and therefore the resilience of the (typically) single tube employed.
Two products currently on the market—the Tower 200 from Body by Jake and the X-Factor from Weider—are door mounted units, use a length of resistance tubing with pulleys and attachment hooks on each end, top and bottom. This limits the stretch to the degree to which the single resistance tube will stretch. There is no adjustment for initiation points other than top and bottom. There are no means provided for mounting the systems on a truck for use by truck drivers while on the road.
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The present invention relates to polymers and more particularly to a copolyadipamide having hexamethyleneadipamide units and a minor portion of pentamethyleneadipamide units, and products prepared therefrom.
Polyadipamide polymers, e.g., polyhexamethyleneadipamide (nylon 66), have a number of positive characteristics, but are thermally unstable at their normal processing temperatures. When kept in the molten state at processing temperature for a long time, polyadipamides form branched/crosslinked, insoluble, nonfusible gel. The formation of gel in the polymer product and on the walls of processing equipment can result in deficient product with poor processibility, particularly when fiber spinning is involved. The fiber spinning breaks which may occur due to gel formation are troublesome and make the winding of large packages impractical.
Certain remedies to gel-formation have been reported such as in U.S. Pat. No. 3,872,055. U.S. Pat. No. 3,872,055 discloses a polyamide composition which has a decreased gel-forming property, specifically a copolyamide of the diamine-dicarboxylic acid type containing phosphinic and phosphonous acid compounds together with an alkali metal compound.
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Portable lighting can be used with electronic devices to illuminate various areas of the device. In some cases, the lighting may be outside the visible spectrum of some predetermined frequency spectrum and uses to accomplish a specific purpose. In these instances, providing controlling software as well as importing and exporting data to portable lighting devices can be burdensome in situations where many devices are used throughout a building or complex.
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Recent trends have developed two major factors in the design of industrial facilities, i.e., the increasingly stringent governmental pollution control requirements, and the cost and availability of energy. Particularly difficult problems in this regard are found in the design of paint spray booth facilities for the application of paint to automative bodies and similar products, due to the enormous volumes of air flow required in the paint spray booths in industry.
The pollution problems are associated primarily with the hydrocarbon liquid constituents, including solvents, thinners and diluents of acrylic and lacquer paints and enamels. Such liquid constituents are vaporized during the paint application, as well as paint drying which vapors pass into air ciculated through the booth. Such air must be circulated at relatively high volume in order to enable the paint sprayers to work in a healthful and clean environment.
The rigorous standards of emissions applied to industrial facilities precludes the discharge of such hydrocarbon or solvent laden air directly into the atmosphere, and such vapors in the discharged air are required to be reduced to very low levels.
A common approach in eliminating such vapors which are combustible is to incinerate the same by passing the air into an incineration chamber which is heated by a burner to raise the temperature of the air sufficiently to cause oxidation of the hydrocarbons into carbon dioxide and water vapor prior to being exhausted by the atmosphere.
However, for the enormous air flow rates exhausted from paint spraying booths, the incineration process requires vast expenditures of energy, thus rendering this solution very costly to implement.
Another alternate approach which has been attempted and considered in this context is the use of adsorber beds such as of activated charcoal, over which the exhaust air is passed for direct adsorption of the solvent vapors, thus enabling their elimination from the exhaust air.
Again, the enormous air volumes in automotive production and similar applications and the need to regenerate the adsorber beds render this approach extremely expensive.
Yet another approach which has been proposed involves the replacement of the hydrocarbon solvent based paint with water based paint, the elimination of vapors thus enabling direct discharge of the exhaust air to the atmosphere, after filtration or other treatment of the air to remove the paint solids.
While effective in this regard, the water based paints require close control over the temperature and humidity of the air supplied to the booth, with air cooling and dehumidification during summertime, and heating and humidification during wintertime operation. This requirement requires considerable capital investment and furthermore entails considerable energy to execute.
Accordingly, it is an object of the present invention to provide a system and process for the elimination of hydrocarbon vapors from the air exhausted from a paint spray facility in which the equipment required is relatively modest and in which the energy expended in the process is relatively modest.
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A torque transmitting device includes a driving member and a driven member. The driven member typically includes a friction surface that must be replaced during the life of the torque transmitting device as wear occurs to the friction surface.
The driven member of the torque transmitting device typically rotates about an axially extending drive shaft. In order to replace the friction surface of the driven member, the torque transmitting device must be disassembled. Replacing the friction surface in this manner is time consuming and expensive.
To accommodate easy replacement, it is known in the art to use a bracket that does not extend for the full circumferential extent of the drive shaft. The bracket, having a friction surface, may be removed from the drive shaft without disassembling the torque transmitting device. The bracket is typically secured to an outer peripheral portion of the torque transmitting device, as opposed to an inner peripheral portion. The bracket, supported only along the outer periphery, extends radially inwardly towards the drive shaft.
It is known in the art to attach the bracket to the driving member by use of axially extending dowels. The dowels extend through apertures in the bracket, and bracket slides axially along the dowels. During operation of the torque transmitting device, the bracket slides axially with respect to the drive shaft when the driving member and driven member are engaged and disengaged.
If the diameter of the aperture in the bracket and the dowel are in close tolerance, the bracket may bind as it is moved axially. If a greater tolerance is provided, the bracket may not maintain proper alignment during axial movement. Properly supporting the bracket for movement in the axial direction is difficult due to the limited support structure. In addition, movement of the bracket is often unstable due to centrifugal forces acting on the bracket. Consequently, the torque transmitting device operates less efficiently. Further, the prior art bracket is subject to vibration or "chatter," particularly at high rotational speeds. Such vibration results in undesirable noise.
It is therefore a goal of the present invention to provide an easily removable bracket having a friction surface for use in a torque transmitting device, wherein the bracket is attached to an outer periphery of the device and is provided with a guide member for additional support during axial movement. A further goal of the invention is to provide the bracket with a guide member that cooperates with another element of the torque transmitting device, such as a housing or cover. A further goal of the present invention is to provide a friction bracket assembly having smooth operation and reduced noise.
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{
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Service providers and device manufacturers are continually challenged to deliver value and convenience to consumers by, for example, providing compelling network services and advancing the underlying technologies. One area of interest has been the development of services and technologies for personal information management (e.g., calendaring, task management, goal planning, and the like). In particular, service providers and device manufacturers face significant technical challenges in adapting such personal information management services for organizing and planning the personal and social lives of users where events, goals, and plans are fluid, dynamic, and nebulous.
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The present invention relates to chemiluminescent compositions which react with a peroxidase and a peroxide to generate chemiluminescence. In particular, the present invention relates to compositions containing novel electron-rich alkenes which react with a peroxidase and a peroxide to produce an excited state carbonyl compound. The invention further relates to assay methods for detecting a peroxidase and for detecting peroxidase-labeled specific binding partners in immunoassays, nucleic acid probe assays and the like.
Peroxidase enzymes such as horseradish peroxidase (HRP) are frequently used as markers or labels in enzyme-linked assays for biological molecules and other analytes of interest such as drugs, hormones, steroids and cancer markers. Chemiluminescent detection of these enzymes offers a safe, convenient and sensitive means to provide a quantitative measure of the amount of enzyme in a sample or of the amount of an enzyme-labeled analyte or labeled specific binding partner for an analyte. Other chemiluminescent reaction schemes have been developed to quantitate the level of particular peroxidase enzymes.
a. Chemiluminescent Peroxidase Substrates. Amino-substituted cyclic acylhydrazides such as the well-known luminol and isoluminol react with H2O2 and a peroxidase catalyst (such as horseradish peroxidase, HRP) under basic conditions with emission of light. This reaction has been used as the basis for analytical methods for the detection of H2O2 and for the peroxidase. Heterocyclic analogs of luminol such as (8-amino-5-chloro-7-phenylpyrido[3,4-d-pyridazine-1,4(2H,3H)dione (M. Ii, et al., Biochem. Biophys. Res. Comm., 193(2), 540-5 (1993)); pyridazinoquinoxalinones (U.S. Pat. No. 5,324,835) and 1,3-disubstituted pyrazolo[4xe2x80x2,3xe2x80x2:5xe2x80x2,6xe2x80x2]pyrido-[2,3-d]-pyrazinediones (Y. Tominaga, et al., Tetrahedron Lett., 36, 8641-4 (1995)) are known to react with a peroxidase and peroxide to produce chemiluminescence. Other hydrazide compounds which are chemiluminescent when oxidized by a peroxidase and a peroxide are hydroxy-substituted phthalhydrazides (U.S. Pat. No. 5,552,298).
Applicant""s U.S. Pat. Nos. 5,491,072, 5,523,212 and 5,593,845 disclose chemiluminescent N-alkylacridan-carboxylic acid esters, thioesters and sulfonimides which produce light upon reaction with a peroxide and a peroxidase for use in detecting peroxidases and in assays. A PCT application (WO 94/02486) describes the chemiluminescent reaction of spiroacridan compounds with hydrogen peroxide. The reaction is enhanced by the addition of horseradish peroxidase.
Various compounds of biological origin, collectively termed luciferins, are oxidized by a peroxidase (summarized in L. J Kricka and G. H. G. Thorpe, in Luminescence Immunoassay and Molecular Applications, K. Van Dyke and R. Van Dyke, eds., CRC Press, Boca Raton, 1990, pp. 77-98). In some instances, hydrogen peroxide is not utilized in which case the enzyme is functioning as an oxidase.
Certain phenol compounds produce chemiluminescence on oxidation with a peroxidase. As examples, pyrogallol B-1 and purpurogallin B-2 are cited in Kricka and Thorpe, ibid. as well as the coumarin-type compounds coumarin, umbelliferone and esculin (D. Slawinska, J. Slowinski, J. Biolumin. Chemilumin., 4, 226-30 (1989)); phloroglucinol B-3 (M. Halmann, et al., Photochem. Photobiol., 30, 165-7 (1979)); and acetaminophen B-4 (K. Schmitt, G. Cilento, Photochem. Photobiol., 51, 719-23 (1990)).
Other miscellaneous compounds reported to produce weak chemiluminescence in the presence of a oxygen or peroxide and a peroxidase are a synthetic Schiff base-containing polymer ((R. Zoulik, et al., Coll. Czech. Chem. Commun., 60, 95-103 (1995)); indole-3-acetic acid in the presence of xanthene dyes with or without hydrogen peroxide (S. Krylov, A. Chebotareva, FEBS, 324(1), 6-8 (1993); tyrosine, tryptophan and chlorpromazine (M. Nakano, J. Biolumin. Chemilumin. 4, 231-40 (1989)) and MCLA B-8 M. (Mitani, et al., J. Biolumin. Chemilumin. 9, 355-61 (1994)) which have the respective structures B-5-B-8 as shown below.
None of the foregoing references disclose the chemiluminescent oxidation of the presently disclosed compounds by a peroxidase
b. Reaction of Enols with HRP. A series of papers describe the peroxidase-catalyzed air oxidation of enolizable aldehydes (H. Gallardo, et al., Biochim. Biophys. Acta, 789, 57-62 (1984); W. J. Baader, et al., Biochem. Ed., 14(4), 190-2 (1986); I. Nantes, et al., Photochem. Photobiol., 63(6), 702-8 (1996)). The reactive substrate is thought to be the small quantity of the enol form in equilibrium with the aldehyde. The reaction of the aldehyde is catalyzed by enol phosphates, but the enol phosphate itself is not consumed. The reference teaches that the enol phosphate does not react with a peroxidase to produce chemiluminescence. Energy transfer to fluorescent energy acceptors increased light emission (M. T. Grijalba, et al., Photochem. Photobiol., 63(6), 697-701 (1996)). Aldehydes masked as enol silyl ethers (Baader, ibid.) or enol acetates were used in coupled assays in which the enol was unmasked in a first step to generate an enol in situ which subsequently reacted with a peroxidase to generate chemiluminescence (A. Campa, et al., Photochem. Photobiol., 63(6), 742-5 (1996)).
c. Peroxidase Enhancers. Numerous enhancers have been employed in order to increase the quantity and duration of chemiluminescence from the reaction of a peroxidases with known chemiluminescent substrates including the aforementioned luminol and the acridancarboxylic acid derivatives. These include benzothiazole derivatives such as D-luciferin, various phenolic compounds such as p-iodophenol, p-phenylphenol, naphthols and aromatic amines as listed in G. Thorpe, L. Kricka, in Bioluminescence and Chemiluminescence, New Perspectives, J. Scholmerich, et al, Eds., pp. 199-208 (1987). Other compounds which function as enhancers of the chemiluminescent oxidation of amino-substituted cyclic acylhydrazides by a peroxidase include 4-(4-hydroxyphenyl)-thiazole (M. Ii, ibid.), a group of compounds disclosed in U.S. Pat. No. 5,171,668, 2-hydroxy-9-fluorenone, and a group of hydroxy-substituted benzoxazole derivatives as disclosed in U.S. Pat. No. 5,206,149 and certain phenylboronic acid compounds as described in U.S. Pat. No. 5,629,168. None of the foregoing references disclose the chemiluminescent oxidation of the present compounds by a peroxidase alone or with the use of enhancers.
d. Enhancement of Chemiluminescent Peroxidase Reactions by Surfactants. Enhancement of the chemiluminescence produced in peroxidase-catalyzed reactions using polymeric and monomeric surfactants is known in the art. Enhancement can occur by affecting the outcome of one or more steps e.g. by increasing the fluorescence quantum yield of the emitter, by increasing the percentage of product molecules produced in the excited state, by increasing the fraction of molecules undergoing the chemiluminescent reaction through inhibition of competing side reactions or by promoting the action of an enzyme catalyst. No clear or consistent pattern exists concerning the effect of polymeric and monomeric surfactants on chemiluminescent reactions. It is impossible to predict which surfactant compounds, if any, may enhance the chemiluminescence from a particular process and can only be determined by substantial experimentation.
The cationic polymeric surfactant poly-N-ethyl-4-vinylpyridinium bromide completely inhibited the chemiluminescent reaction of luminol by a negatively charged insulin-peroxidase conjugate and diminished chemiluminescence to a lesser extent when the native enzyme was used (S. B. Vlasenko, et al., J. Biolumin. Chemilumin., 4, 164-176 (1989)).
A published Japanese Patent Application No. JP 06,242,111 and a paper (R. Iwata, et al., Anal. Biochem., 231, 170-4 (1995)) disclose the use of nonionic surfactant and skim milk in the chemiluminescent peroxidation of luminol to lower background emission or enhance signal/noise.
None of the foregoing references disclose the chemiluminescent oxidation of the present compounds by a peroxidase or chemiluminescence enhancement with surfactants.
d. Assays using HRP. The enzyme horseradish peroxidase has found widespread use in enzyme immunoassays and DNA hybridization assays with chemiluminescent detection using luminol or isoluminol as substrate. Commercially available kits using HRP conjugates and enhanced luminol chemiluminescent detection are available. Chemiluminescent peroxidase assays are also disclosed in the aforementioned U.S. Pat. Nos. 5,491,072, 5,523,212 and 5,593,845. No references disclose the chemiluminescent peroxidase assays using the present compounds as the substrates.
It is an object of the present invention to provide compositions containing compounds which react with a peroxidase and a peroxide to provide chemiluminescence.
It is another object of the present invention to provide compositions containing compounds which react with a peroxidase and a peroxide to provide chemiluminescence for detection of the peroxidase.
It is also an object of the present invention to provide compositions containing compounds of formula I containing a carbon-carbon double bond substituted at one terminus of the double bond with two atoms selected from oxygen or sulfur each attached to another group X or R1 and substituted at the other terminus of the double bond with two groups A1 and A2 selected so that an excited state product A1A2Cxe2x95x90O* results upon reaction of I with a peroxidase and a peroxide.
It is a further object of the present invention to provide compositions containing compounds of formula I wherein A1 and A2 together with the carbon atom to which they are bonded form a heterocyclic or carbocyclic ring. In particular the ring can be a nitrogen, sulfur or oxygen-containing heterocyclic ring group.
It is a further object of the present invention to provide compositions containing compounds of formula I wherein when Z2 is O the group attached to the oxygen atom is part of an alkoxy group, an aryloxy group, an aralkyloxy group, a phosphate mono-, di- or triester group, a carboxyl ester group, a sulfate group, a sugar group or a silyl ether group and when Z2 is S the group attached to the sulfur atom is part of the equivalent thio groups.
It is a further object of the present invention to provide methods for generating chemiluminescence upon reaction with a peroxidase and a peroxide employing the present compositions.
Still further, it is an object of the present invention to provide a method and compositions for enhancing the chemiluminescence produced on reaction of compounds of the present invention with a peroxidase.
It is yet another object of the present invention to provide chemiluminescent compositions and methods for use in detecting peroxidases and conjugates in immunoassays, nucleic acid probe assays, western blot assays, Southern blot assays and other assays by generally known methods which employ enzyme labels for detection of analytes. The assays are thus useful for detecting analytes in such assays by detecting the peroxidase or conjugate and relating the chemiluminescence produced thereby to the presence or amount of the analyte.
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Magnetic resonance imaging (MRI) provides an important imaging modality for numerous applications and is widely utilized in clinical and research settings to produce images of the inside of the human body. As a generality, MRI is based on detecting magnetic resonance (MR) signals, which are electromagnetic waves emitted by atoms in response to state changes resulting from applied electromagnetic fields. For example, nuclear magnetic resonance (NMR) techniques involve detecting MR signals emitted from the nuclei of excited atoms upon the re-alignment or relaxation of the nuclear spin of atoms in an object being imaged (e.g., atoms in the tissue of the human body). Detected MR signals may be processed to produce images, which in the context of medical applications, allows for the investigation of internal structures and/or biological processes within the body for diagnostic, therapeutic and/or research purposes.
MRI provides an attractive imaging modality for biological imaging due to the ability to produce non-invasive images having relatively high resolution and contrast without the safety concerns of other modalities (e.g., without needing to expose the subject to ionizing radiation, e.g., x-rays, or introducing radioactive material to the body). Additionally, MRI is particularly well suited to provide soft tissue contrast, which can be exploited to image subject matter that other imaging modalities are incapable of satisfactorily imaging. Moreover, MR techniques are capable of capturing information about structures and/or biological processes that other modalities are incapable of acquiring. However, there are a number of drawbacks to MRI that, for a given imaging application, may involve the relatively high cost of the equipment, limited availability and/or difficulty in gaining access to clinical MRI scanners and/or the length of the image acquisition process.
The trend in clinical MRI has been to increase the field strength of MRI scanners to improve one or more of scan time, image resolution, and image contrast, which, in turn, continues to drive up costs. The vast majority of installed MRI scanners operate at 1.5 or 3 tesla (T), which refers to the field strength of the main magnetic field B0. A rough cost estimate for a clinical MRI scanner is on the order of one million dollars per tesla, which does not factor in the substantial operation, service, and maintenance costs involved in operating such MRI scanners.
Additionally, conventional high-field MRI systems typically require large superconducting magnets and associated electronics to generate a strong uniform static magnetic field (B0) in which an object (e.g., a patient) is imaged. The size of such systems is considerable, with a typical MRI installment including multiple rooms for the magnet, electronics, thermal management system, and control console areas. The size and expense of MRI systems generally limits their usage to facilities, such as hospitals and academic research centers, which have sufficient space and resources to purchase and maintain them. The high cost and substantial space requirements of high-field MRI systems results in limited availability of MRI scanners. As such, there are frequently clinical situations in which an MRI scan would be beneficial, but due to one or more of the limitations discussed above, is not practical or is impossible, as discussed in further detail below.
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{
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The present invention relates to a percussive down-the-hole hammer for rock drilling, and a piston used therein.
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{
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Embodiments described herein relate generally to Fibre Channel over Ethernet (FCoE) networks, and, in particular, to implementing a Fibre Channel zone policy in a FCoE network.
Some known FCoE networks use a Fibre Channel switch (e.g., a Fibre Channel Forwarder (FCF)) to connect server and/or storage devices and enforce a Fibre Channel zone policy. In such FCoE networks, server and/or storage devices are typically connected to and logged in with an FCF either directly or through an FCoE Initialization Protocol (FIP) snooping bridge. Meanwhile, FCoE frames are typically transmitted to the FCF before they can be forwarded to the destined server and/or storage devices. Because an FCF can only handle a limited number of devices and/or frames, however, such FCoE networks are typically not scalable.
Some other known FCoE networks implement a Virtual Node (VN) Port to VN Port (VN2VN) deployment, where each server or storage device is allowed to connect to and communicate with each other in a peer-to-peer fashion, without the presence of an FCF. In such a VN2VN deployment, however, a Fibre Channel zone policy is typically provisioned to and enforced at each server or storage device, resulting in an additional provisioning and enforcement overhead at each server or storage device.
Accordingly, a need exists for methods and apparatus that can implement a Fibre Channel zone policy in an FCoE network without introducing additional forwarding-plane state information at end nodes besides that used for FIP-snooping.
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The present invention is directed toward the field of small, hand-held elect-Ionic devices such as personal data assistants (PDA's), personal information managers (PIM's), two-way pagers and the like. In particular, the system and method of the present invention provide the user of the hand-held device with the ability to input data with a minimal amount of key strokes and optimized for use substantially with the thumbs.
In a two-way paging system that provides two-way, full text messaging, there is a need to permit the user to initiate messages and to respond to messages in a timely fashion and with text entirely created by the user. In order to keep the form factor of the two-way pager small enough to be worn on the body of the user, such as with a belt clip, the input device needs to be small, have a minimal number of keys and optimized for use with a minimal number of key strokes. Prior art systems have attempted to address these needs by incorporating virtual keyboards or pen-based input systems for user inputs to the device, but such systems require the user to input data in an unfamiliar manner. Additionally, in a small hand-held messaging device, such as a two-way pager, these systems prove awkward to use.
In order to provide a hand-held electronic device that permits a user the opportunity to enter data into an address book, a calendar, a task list, an email message or a similar text file that requires user-generated data, the instant invention is directed to an input device that is oriented to be used substantially through use of the thumbs. This is accomplished first by providing a keyboard with a minimal number of keys, but with the keys representing the alphabet generally placed in the same order as they would appear on a standard keyboard, such as in a standard QWERTY or a DVORAK keyboard layout. The use of a keyboard layout that is familiar to the user enables the user to immediately use the device without having to hunt for the keys he or she wishes to use.
Although the layout is similar to a standard keyboard, the keys are placed at an orientation 10 and in a particular shape that attempts to maximize the surface area of the thumb hitting the key and to provide the user with a comfortable position of the hands for data input. Also, the orientation encourages input by the thumbs, which the inventors of the instant invention have discovered to be faster and more accurate in small hand-held electronic devices than touch-typing or “hunting and pecking” typing.
An additional feature of the invention is the use of an additional input means for control of functions that might otherwise be controlled by a keyboard that included function keys. To encourage data entry using thumbs and again to minimize the number of keys on the keyboard, the instant invention also includes a thumb-wheel for control of menus for selection of forms and functions relevant to data input. As discussed below, one of the data forms the thumbwheel is implemented to accommodate is a special character set. The thumb-wheel is positioned in close proximity to the keyboard to enable the easily transition from thumb-based typing to thumb control of forms and functions.
In addition to hardware features that encourage optimal data entry though the use of thumbs, there are several software features that are designed to minimize keystrokes and aid in entry of data.
The features of this invention, both individually and collectively, have not, to the knowledge of the inventors, been applied to a small hand-held electronic device that requires user-generated data entry. To permit efficient operation of such devices while keeping the form factor of the device small enough to be worn on the body, there is a general need for a hand-held electronic device that can fit in the palm of the hand and that can be operated substantially with the thumbs.
There is a further need for a keyboard for a palm-size data entry device with keys placed at an angle to optimize operation of the keyboard by the use of the thumbs.
There remains another need for a keyboard with keys that are shaped arid sized to maximize contact with the thumbs while minimizing the keyboard area required for such keys.
There also remains a need for an auxiliary input device that is to be operated by the thumb for data inputs forms and function control and that, in conjunction with the keyboard, encourages and permits data entry and management through input performed substantially by the thumbs.
There remains still another need for a software-implemented user interface system that is designed, at least in part, to support and encourage data entry through use of the thumbs.
There remains another need for facilitating entry of special or international characters with the thumbs while limiting the keyboard area.
There remains another need for automatically entering certain common punctuation thereby reducing repetitive key entry and increasing the speed of data entry.
There remains another need for automatically entering certain common phrases or electronic signatures without tediously typing the full phrase or electronic signature.
There remains another need for easily removing automatic features when such features are not desired.
There remains another need for executing a set of common instructions for a particular task with a minimum of use-r data entry.
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The following Patent Document 1 discloses a molding die that is used to coat an optical fiber and is used to form a mold portion including a first mold groove and a second mold groove by coupling a first base on which the first mold groove is formed to a second base on which the second mold groove is formed; a first position-adjusting groove into which a position-adjusting member is to be fitted is formed on a surface on which the first mold groove of the first base is formed; a second position-adjusting groove into which a position-adjusting member is to be fitted is formed on a surface on which the second mold groove of the second base is formed; a resin injection passage that is used to inject resin into the mold portion is formed on at least one of the first base and the second base; a first resin discharge groove that is used to discharge the resin from the mold portion is formed across the first mold groove and the first position-adjusting groove on the surface on which the first mold groove of the first base is formed; a second resin discharge groove that is used to discharge the resin from the mold portion is formed across the second mold groove and the second position-adjusting groove on the surface on which the second mold groove of the second base is formed; two first resin discharge grooves and two second resin discharge groove are provided thereon; and the two resin discharge grooves are positioned so as to sandwich the resin injection passage therebetween.
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1. Field of the Invention
The present invention relates to a displayer and a pixel circuit thereof. More particularly, the present invention relates to a displayer and a pixel circuit thereof, in which two pixel electrodes belongs to a same pixel type and be disposed adjacent to each other.
2. Descriptions of the Related Art
As liquid crystal displayers (LCDs) are continuously developing towards large-sized ones, continuous progress also needs to be made in wide viewing angle technologies of LCD panels in order to overcome the problem about the viewing angle with large-sized displayers. Currently, multi-domain vertical alignment (MVA) LCD panels and polymer stabilized alignment (PSA) LCD panels are among the wide viewing angle technologies that are commonly used.
To improve the color shift in the LCD panels, a kind of advanced-MVA LCD panel has been proposed. In the advanced-MVA LCD panel, each of pixels is divided into a main display region (i.e., a main-pixel) and a sub-display region (i.e., a sub-pixel); and through a proper circuit design and a proper driving method, the main-pixel and the sub-pixel in the same pixel are provided with different voltages respectively to improve the color shift. Accordingly, designs in which a single pixel region has two data lines and one scan line (also referred to as a gate line) or in which a single pixel region has one data line and two scan lines are introduced, which are called as the 2G1D structure and the 2D1G structure respectively. Taking the 2D1G structure as an example, a pixel region comprises two sub-pixels, which are controlled by different data lines respectively.
Furthermore, referring to FIG. 1, a schematic view of a pixel circuit is shown therein. Generally speaking, there are two kinds of different electrical connection structures between the aforesaid MVA LCD and the data lines, i.e., positive (P) pixel electrodes and negative (N) pixel electrodes. The two kinds of pixel electrodes are staggered in the pixel circuit in a PNPNPN or NPNPNP pattern. However, this staggered pattern is prone to cause color shift in an image generated by the pixel circuit when a specific frame is displayed, thus degrading the displaying quality of the LCD.
Specifically, among pixel electrodes in FIG. 1, R represents a red pixel electrode, G represents a green pixel electrode, B represents a blue pixel electrode, a white background represents that the corresponding pixel displays a bright state, and a black background represents that the corresponding pixel displays a dark state. As can be known from FIG. 1, when a frame is displayed and the R pixel electrodes, the G pixel electrodes and the B pixel electrodes are all in the bright state or all in the dark state simultaneously, the color shift phenomenon will occur. Taking the arrangement of the pixel electrodes in FIG. 1 as an example, when a frame of a checkerboard pattern is displayed, the green main-pixels in the main-pixel rows A, B, C are all positive.
In detail, referring to FIG. 2, there is shown a schematic view depicting that a common electrode signal is pulled away from an original direct current (DC) level by a data line signal with the positive and negative polarities. When the data line signal (Vdata) has a transient, the common electrode voltage (VCOM) at the pixel array side is pulled by Vdata to result in the waveform as shown in FIG. 2. When the potential of the data line signal rises, the VCOM will be raised; otherwise, when the potential of the data line signal falls, the VCOM will be dropped. Therefore, when the data lines are driven in the column inversion manner, in one main-pixel rows A, B, C, the green main-pixels are all of the positive polarity and the red main-pixels and the blue main-pixels are all of the negative polarity. Thereby, the VCOM signal is pulled towards the polarity direction of the red (or blue) main-pixels. Therefore, in the frame displayed, the green color has a gray scale higher than the originally defined level while the other two colors have gray scales lower than the originally defined levels. This causes the aforesaid color shift (bias to the green color) phenomenon. Furthermore, when arrangement of the pixels of different colors in the pixel electrodes are altered, different color shift phenomena will be caused.
Accordingly, an urgent need exists in the art to effectively prevent occurrence of the color shift phenomenon in an image generated by the pixel circuit so as to improve the displaying quality of the LCD and increase the added value of this industry.
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People are increasingly interacting with computers and other electronic devices in new and interesting ways. For example, various applications enable a user to take a picture of a product or item using a computing device and upload that picture to a service capable of identifying the product or item for the user. Other applications enable a user to provide input to a device through various motions, such as by making a simple hand gesture with respect to a device. Image recognition can be difficult to implement on consumer devices, however, particularly for mobile or portable computing devices that generally have relatively simple camera elements and limited processing capacity. In certain approaches, the amount of image processing can be reduced by separating foreground objects from an image background. In at least some approaches, this separating involves taking at least two pictures and subtracting out portions that do not change. If an object in the foreground moves between pictures, or is highlighted in one picture due to a flash, then that object will not appear substantially the same in both pictures, and thus can be identified relatively easily as the non-changing background will be substantially removed through the subtraction process.
Image subtraction approaches, however, generally rely on the fact that the background and other objects in a viewable range of a camera remain relatively static between the taking of consecutive pictures. If the background moves relative to the computing device, such as due to a movement of the computing device, portions of the background may not appear at substantially the same location in each of the subsequent pictures. Accordingly, the subtraction process may not adequately separate any foreground objects from the background. The process might then result in artifacts, false positives, or inconclusive determinations, or might at least require significantly more processing power to attempt to identify objects in the foreground of the pictures.
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A substantial number of handheld computing devices, such as cellular phones, tablets, and E-Readers, make use of a touch screen display not only to deliver display information to the user but also to receive inputs from user interface commands. While touch screen displays may increase the configurability of the handheld device and provide a wide variety of user interface options, this flexibility typically comes at a price. The dual use of the touch screen to provide content and receive user commands, while flexible for the user, may obfuscate the display and cause visual clutter, thereby leading to user frustration and loss of productivity.
The small form factor of handheld computing devices requires a careful balancing between the displayed graphics and the area provided for receiving inputs. On the one hand, the small display constrains the display space, which may increase the difficulty of interpreting actions or results. On the other hand, a virtual keypad or other user interface scheme is superimposed on or positioned adjacent to an executing application, requiring the application to be squeezed into an even smaller portion of the display.
This balancing act is particularly difficult for single display touch screen devices. Single display touch screen devices are crippled by their limited screen space. When users are entering information into the device, through the single display, the ability to interpret information in the display can be severely hampered, particularly when a complex interaction between display and interface is required.
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Aerial refueling of a receiver aircraft from a tanker aircraft is commonly performed. Nevertheless, aerial refueling is still a difficult and dangerous maneuver that is typically attempted only by military personnel throughout the world. Today, usually only two types of aerial refueling systems are used: extendable boom systems and a hose-and-drogue systems.
In a hose-and-drogue system, the drogue is attached to the outlet end of a hose. The inlet end of the hose is attached to a hose reel onto which the hose is wound. The hose reel is typically mounted either within a tanker aircraft fuselage or on a refueling pod or module which is attached to the bottom of the tanker aircraft. The hose reel is commonly connected to a motor and/or pump that is hydraulically driven. The hydraulic motor-pump can be connected through a coupling system, which may include, e.g., various gear boxes, shafts, and couplings. When the hose is deployed from the tanker aircraft, the drogue encounters drag and the hose reel rotates in a trail direction in which the hose extends behind the tanker aircraft.
When the hose and the drogue are fully extended, a pilot of a receiver aircraft maneuvers the receiver aircraft to engage a refueling probe of the receiver aircraft with the drogue. Danger arises because the high speeds of the aircrafts relative to the ground and to each other can result in the drogue being hit with considerable force during engagement. Such engagements may create slack in the hose that must be quickly eliminated. Otherwise, the risk of aircraft accidents increases substantially. Retracting the hose onto the hose reel eliminates the slack.
After the drogue is engaged, fuel can be pumped from the tanker aircraft to the receiver aircraft. When refueling is completed, the pilot of the receiver aircraft disengages the refueling probe from the drogue. The hose can then be retracted onto the hose reel for storage by rotating the hose reel in a retract direction.
Thus, when the hose extends, it drives the hose reel in a trail direction while the hydraulic motor-pump operates in a pump mode. Conversely, operating the hydraulic motor-pump in a motor mode rotates the hose reel in the retract direction, causing the hose to be retracted onto the hose reel. In the trail mode, hose position can be controlled independently from variations in hose tension. In the retract mode, hose tension can be controlled independently from variations in hose position.
Aerial refueling systems have utilized hydraulic motor-pumps that incorporate fixed displacement hydraulic motors that control the extension of the hose in a pump mode and control the retraction of the hose in a motor mode. However, such systems suffer from low hose retraction rates and accessory components that increase overall weight and response time of the system. Information relevant to attempts to address these problems can be found in U.S. Pat. Nos. 6,454,212 and 6,866,228, which disclose variable displacement hydraulic motor-controlled hose reel drive systems.
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This invention relates to silver-containing, supported catalysts for the epoxidation of alkene, especially ethylene, to the corresponding alkylene oxide, e.g., ethylene oxide, which contain a stability and/or efficiency and/or activity enhancing amount of a cobalt-containing component.
Ethylene oxide is commercially produced by the epoxidation of ethylene over silver-containing catalyst at elevated temperature. Considerable research efforts have been devoted to providing catalysts that increase the efficiency, or selectivity, of the process to ethylene oxide.
The manufacture of ethylene oxide by the reaction of oxygen or oxygen-containing gases with ethylene in the presence of a silver catalyst is an old and developed art. For example, U.S. Pat. No. 2,040,782, patented May 12, 1936, describes the manufacture of ethylene oxide by the reaction of oxygen with ethylene in the presence of silver catalysts which contain a class of metal-containing promoters. In Reissue U.S. Pat. No. 20,370, dated May 18, 1937, Leforte discloses that the formation of olefin oxides may be effected by causing olefins to combine directly with molecular oxygen in the presence of a silver catalyst. From that point on, the prior art has focused its efforts on improving the catalyst""s efficiency in producing ethylene oxide.
In characterizing this invention, the terms xe2x80x9cconversionxe2x80x9d, xe2x80x9cselectivityxe2x80x9d, and xe2x80x9cyieldxe2x80x9d are employed as defined in U.S. Pat. No. 3,420,784, patented Jan. 7, 1969, at column 3, lines 24-35 inclusive. This definition of xe2x80x9cselectivityxe2x80x9d is consistent with that disclosed in U.S. Pat. No. 2,766,261 at column 6, lines 5-22, and U.S. Pat. No. 3,144,916, lines 58-61. The definitions of xe2x80x9cyieldxe2x80x9d and xe2x80x9cconversionxe2x80x9d have more varied meaning in the art and are not to be employed as defined, for example, in the aforementioned U.S. Pat. No. 2,766,261. The terms xe2x80x9cefficiencyxe2x80x9d and xe2x80x9cselectivityxe2x80x9d, as used throughout the specification and claims are intended to be synonymous.
Silver catalysts employed in the manufacture of ethylene oxide have undergone significant changes since their initial period of development. As reported by the art, silver particles were first deposited upon support materials with little attention being paid to support properties, such as surface area, pore volume and chemical inertness. As the art evolved, there developed special technologies related to carriers or supports containing silver that were more effective for the reaction of ethylene with oxygen to produce ethylene oxide. Today, most supports for the silver catalysts are shaped particulate materials which can be loaded in the interior of a reactor wherein the reacting gases and the gaseous products of the reaction are capable of flowing in and about these particulate materials to pass through the reactor and be recovered. The size and shape of the support are variable factors and the particular size and shape selected are peculiar to the reactor employed, the gas flow required, and the pressure drop across the reactor, with other factors also being considered.
The carriers that have been employed are typically made of inorganic materials, generally of a mineral nature. In most cases, the preferred carrier is made of alpha-alumina, such as has been described in the patent literature: see for example, U.S. Pat. Nos. 2,294,383; 3,172,893; 3,332,887; 3,423,328; and 3,563,914.
The carriers which are employed for the manufacture of most, if not all, commercially employed ethylene oxide catalysts are produced by companies who do not produce such catalysts. As a rule, the methods of making such carriers are trade secrets of significant value to the carrier manufacturers. Consequently, the catalyst manufacturer cannot know how the carrier is made. Critical to making a carrier which proves uniquely desirable for the manufacture of a successful catalyst can be a number of factors, such as the purity and other physical/chemical properties of raw materials used to make the carrier and the method by which the carrier is made.
The silver that is deposited on these carriers is thought to be in the form of small particles because that is all that can be seen by current microscopic techniques. The patent literature indicates that the size of the silver is a factor in the effectiveness of the catalyst and in most cases fine particle silver is obtained utilizing the standard processes in the art; see, for example, U.S. Pat. Nos. 2,554,459; 2,831,870; 3,423,328 (specifies that silver particles of 150-400 Angstroms are employed); U.S. Pat. No. 3,702,259 (disclosed a preparation procedure for forming silver particles less than 1 micron in diameter) and U.S. Pat. No. 3,758,418 (discloses silver particles having a diameter less than 1000 Angstroms). Improvements in microscopic examinations of silver catalysts enable the observation that the particle size ranges to even smaller values.
The deposition of silver onto the carrier can be achieved by a number of techniques but the two techniques which are most frequently employed involve, in one case, the impregnation of the support with a silver solution followed by heat treatment of the impregnated support to effect deposition of the silver on the support and, in the other case, the coating of the silver on the support by the precipitation of silver or the preformation of silver into a slurry such that the silver particles are deposited on the support and adhere to the support surface when the carrier or support is heated to remove the liquids present. These various procedures are exemplified in various U.S. Patents such as U.S. Pat. Nos. 2,773,844; 3,207,700; 3,501,407; 3,664,970 (see British Patent 754,593) and U.S. Pat. No. 3,172,893.
The surface area provided by the support has been the subject of considerable interest in the development of silver catalysts. Disclosures concerning the surface area of the catalyst carrier can be found in U.S. Pat. No. 2,766,261 (which discloses that a surface area of 0.002-10 m2/gm is suitable); U.S. Pat. No. 3,172,893 which depicts a porosity of 35-65% and a pore diameter of 80-200 microns); U.S. Pat. No. 3,725,307 which depicts a surface area of less than 1 sq.m/gm and an average pore diameter of 10-15 microns); U.S. Pat. No. 3,664,970 (which utilizes a support having a minimum porosity of about 30%, at least 90% of the pores having diameters in the range of 1-30 microns, and the average of such diameters being in the range of 4-10 microns); and U.S. Pat. No. 3,563,914 which utilizes a catalyst support having a surface area of less than 1 sq. m/gm, a volume of 0.23 ml/gm and a particle size between 0.074 and 0.30 mm). Low surface area, inert alpha-alumina is favored by the prior art.
It has been known for a long time that impurities present in the catalyst and/or the gas phase can materially impact upon the reaction. In the early development of the art, there were no techniques available for identifying or measuring such impurities. Consequently, one could not isolate the role that such impurities played. However, even in the earliest periods of the development of the art, the use of alkali metals as promoters for the silver catalyzed production of ethylene oxide was extremely well known in the art. U.S. Pat. No. 2,177,361, issued October 1939, has a teaching of the use of alkali metals in silver catalysts. U.S. Pat. No. 2,238,471 discloses that lithium is very desirable as a promoter but that potassium and cesium are detrimental when used in amounts of essentially 10% by weight of potassium hydroxide or cesium hydroxide to the silver oxide employed in making the catalyst. Later, U.S. Pat. No. 2,404,438 states that sodium and lithium are effective promoters for this reaction. Essentially the same teaching can be found in U.S. Pat. No. 2,424,084. U.S. Pat. No. 2,424,086 generalizes about alkali metals as promoters and specifies sodium in particular. In U.S. Pat. No. 2,671,764 (the Sacken sulfate patent), the patentees believe that alkali metals in the form of their sulfates are effective as promoters for such silver catalysts. In particular, the patentees state that sodium, potassium, lithium, rubidium or cesium sulfates may be used as promoters.
U.S. Pat. No. 2,765,283 describes the pretreatment of a support with a dilute solution of a chlorine-containing compound and indicates that such chlorine compounds should be inorganic. Particular illustrations cited of suitable inorganic chlorine compounds included sodium chloride, lithium chloride and potassium chlorate. This patent specifies that the amount of the inorganic chlorine-containing compound which is deposited on the catalyst support is from 0.0001% to 0.2% by weight based on the weight of the support. U.S. Pat. No. 2,615,900 to Sears describes the use of metal halide in the treatment of the supported catalyst and specifies that such halides can be of alkali metals such as lithium, sodium, potassium and cesium. The metal halide is present in the range of 0.01% to 50% based upon the weight of metallic silver. The patent also specifies that mixtures of the individual metal halides generally classified in the patent may be used to advantage to enhance the break-in period of a new catalyst composition while at the same time maintaining a moderate but steady activity of the catalyst over an extended period of time during normal operation. Thus, one particular metal halide treated catalyst would provide a short-term high initial activity whereas another of the metal halides would provide a longer term moderate activity for the catalyst. This patent takes the position that the metal halides which are provided in the catalyst serve to inhibit the combustion of ethylene to carbon dioxide and thus classifies these materials as catalyst depressants or anticatalytic materials.
U.S. Pat. No. 2,709,173 describes the use of a silver catalyst for making ethylene oxide in which there are provided simultaneously with the introduction of silver to the solid support, any of the alkali metal halides such as lithium, sodium, potassium, and rubidium compounds of chlorine, bromine and iodine, to enhance the overall production of ethylene oxide. The patent specifies small amounts xe2x80x9cof less than about 0.5% are desirable.xe2x80x9d In particular, the patent emphasizes xe2x80x9cproportions of alkali metal halide within the range of about 0.0001 to about 0.1%xe2x80x9d are most preferred. The patent states that xe2x80x9calthough the preferred catalyst composition contains a separate promoter it is not always necessary since during preparation of the catalyst the alkali metal halide may be converted to some extent to the corresponding alkali metal oxide which acts as a promoter.xe2x80x9d U.S. Pat. No. 2,766,261 appears to draw from the teachings of U.S. Pat. No. 2,238,474 in that cesium and potassium are said to be detrimental in silver catalysts; sodium and lithium are suggested as useful promoters. However, U.S. Pat. No. 2,769,016 finds that sodium, potassium and lithium are promoters when used in the silver catalysts. This latter patent also recommends the pretreatment of the support with dilute solutions of sodium chloride, lithium chloride or potassium chlorate.
U.S. Pat. No. 2,799,687 to Gould, et al., states that the addition of metal halides within the range described by Sears in U.S. Pat. No. 2,615,900 is not productive of optimum results. This is said to be especially true in the case of alkali metal halides, particularly the chloride and fluoride of sodium and potassium. The patentees recommend that the inorganic halide component of the catalyst be maintained within the range of 0.01-5 weight percent, preferably 0.01 to 0.1 weight percent, based on the weight of the xe2x80x9csilver oxidative catalytic component,xe2x80x9d i.e., the silver salt transformed into elemental silver. U.S. Pat. No. 3,144,416 mentions a variety of metals as promoters and one of them is cesium. U.S. Pat. No. 3,258,433 indicates that sodium is an effective promoter. U.S. Pat. No. 3,563,913 recommends the use of alkali metals such as lithium compounds as promoters. The preferred amount of promoting material is said to be about 0.03 to 0.5%, by weight of metal oxide based on the weight of the support. U.S. Pat. No. 3,585,217 states that alkali metal chlorides xe2x80x9care known to counteract the formation of carbon dioxidexe2x80x9d and xe2x80x9cmay be incorporated into the catalyst.xe2x80x9d U.S. Pat. No. 3,125,538 discloses a supported silver catalyst containing a coincidentally-deposited alkali metal selected from among potassium, rubidium and cesium in a specified gram atom ratio relative to silver. The weight of silver is preferably 2-5% by weight of the catalyst. The patentees characterize this catalyst as being especially suitable for the reaction of nitric oxide with propylene. This same catalyst is produced inherently by the processes of the examples of U.S. Pat. No. 3,702,259, as discussed previously, which patent promotes their use for making ethylene oxide. U.S. Pat. Nos. 3,962,136 and 4,012,425 also disclose that same catalyst as being useful for ethylene oxide production. U.S. Pat. No. 3,962,136 describes the coincidental deposition of alkali metal with the silver on the support, the alkali metals being present in their final form on the support in the form of an oxide in which the oxide consists of cesium, rubidium or mixtures of both, optionally combined with a minor amount of an oxide of potassium. The amount of such oxide is from about 4.0xc3x9710xe2x88x925 gew/kg to about 8.0xc3x9710xe2x88x923 gew/kg of total catalyst. U.S. Pat. No. 4,356,312 describes the use of the same catalyst. U.S. patent application Ser. No. 317,349, filed Dec. 21, 1972, which is a parent to U.S. Pat. Nos. 3,962,136 and 4,010,115 and others, contains some interesting data deserving of comment. According to example 2 which contains some comparative experiments, there is described the manufacture of a catalyst which contains 310 parts per million by weight of coincidentally-added potassium and that catalyst when employed as an ethylene oxidation catalyst was found to be inactive for the production of ethylene oxide.
U.S. Pat. No. 4,207,210 (corres. Belgium Patent 821,439, based upon British Patent Specification 1,489,335) discloses that a catalyst can be made that is equivalent to that produced in the so-called parent applications cited in U.S. Pat. Nos. 3,962,136, 4,012,425, and 4,010,115 by using a sequential procedure by which the alkali metal is supplied to the support. Thus, the criticality in the method of deposition of alkali metal in the catalyst appears doubtful in the face of that type of disclosure and the disclosure of U.S. patent Nos. 4,033,903 and 4,125,480 which describe subjecting used silver-containing catalysts to a post-addition of one or more of potassium, rubidium or cesium. Apparently, such treatment regenerates the catalyst""s ability to enhance selectivity to ethylene oxide. Another patent which tends to indicate that a post-addition of alkali metal such as cesium gives results equivalent to either pre-addition or simultaneous addition is U.S. Pat. No. 4,066,575.
German offenlegungsschrift 2,640,540 discloses in its examples a silver catalyst for ethylene oxide production containing sodium and either potassium, rubidium or cesium.
Japanese Application Publication Disclosure No. 95213/75 is directed to a process for producing ethylene oxide using a catalyst composition comprising silver, barium, potassium and cesium in specified atomic ratios. Table I of this disclosure summarizes the efficiencies achieved with the various catalyst compositions of the examples.
U.S. Pat. No. 4,039,561 discloses a catalyst for preparing ethylene oxide containing silver, tin, antimony, thallium, potassium, cesium and oxygen in specified atomic ratios.
Belgium Patent No. 854,904 discloses silver catalysts containing various mixtures of sodium and cesium. U.K. Patent Application 2,002,252 (counterpart of U.S. Pat. No. 4,248,740) discloses silver catalysts including promoters containing alkali metal, alkaline earth metals, elements of groups III, IV, V and VIII of the periodic table, with the preferred promoters being compounds of barium, tin, antimony, thallium, potassium, and cesium. This patent application discloses, in Table 2, supported silver catalysts containing various mixtures of cesium and thallium, some of which additionally contain potassium or antimony. U.S. Pat. No. 4,007,135 broadly discloses (in column 2, lines 25-30) silver catalysts for alkylene oxide production containing silver xe2x80x9ctogether with a promoting amount of at least one promoter selected from lithium, potassium, sodium, rubidium, cesium, copper, gold, magnesium, zinc cadmium, strontium, calcium, niobium, tantalum, molybdenum, tungsten, chromium, vanadium and barium . . . xe2x80x9d. U.S. Pat. Nos. 3,844,981 and 3,962,285 disclose catalysts and processes for epoxidizing olefins in the presence of a multimetallic component. The catalyst in the U.S. Pat. No. 3,962,285 patent is said to comprise a minor amount of one or more of palladium, ruthenium, rhenium, iron and platinum with a major amount of silver. The U.S. Pat. No. 3,844,981 patent discloses the preparation of the catalyst from a decomposable salt of group 7b, 1b or the iron group of group 8 of the Periodic Table of the Elements. Preferably, the salt is selected from the group of gold, copper, rhenium, manganese and iron salts. While the patentee contemplates that these metals are in the metallic state, oxidation during epoxidation conditions may occur with one or more of these metals, e.g., rhenium, to form oxyanions containing the metal.
U.S. Pat. No. 2,040,782 discloses silver-containing catalysts for the manufacture of alkylene oxides which catalysts:
xe2x80x9cmay be considerably enhanced by the admixture with the catalytic material of small quantities of other materials capable of acting as promoters. Suitable promoters, which may be used singly or in combination, include the metals such as copper, gold, iron, manganese, nickel, cobalt, cerium, thorium and zinc.xe2x80x9d (Page 2, column 1, lines 3 to 9)
U.S. Pat. No. 2,605,239 discloses the use of beryllium oxide as a promoter. Other promoter metals such as copper, aluminum, manganese, cobalt, iron, magnesium, gold, thorium, nickel, cesium and zinc are suggested. These promoter metals are to be incorporated into the catalyst by mechanical mixture or coprecipitation.
U.S. Pat. No. 2,615,900, states:
xe2x80x9cThe activity of the silver may be enhanced by inclusion in the silver catalyst of promoters such as iron, nickel, copper, gold, platinum, manganese, cobalt, cerium, thorium, zinc, and the oxides, hydroxides, and carbonates of alkali metal and alkaline earth metals.xe2x80x9d (Column 3, lines 33 to 38) Japanese patent application Kokai 78/39404 discloses a gas phase process for the epoxidation of three and four carbon atom olefins in the presence of a silver-cadmium-silicon catalyst. The patent applicant states that other components can be incorporated in the catalyst such as elements of Groups I, II, III and VIII such as cesium, copper, gold, magnesium, calcium, beryllium, barium, zinc, aluminum, lanthanum, cerium, zirconium, thorium, iron, cobalt, nickel and platinum.
U.S. Pat. No. 3,758,418 discloses catalysts prepared by a coating technique. Among the catalysts suggested in the patent are those used for the manufacture of ethylene oxide. The metals that can be deposited are said to include the catalytically active metals found in Group IIIb to Va of the Periodic Table.
Japanese patent application Kokai 89/01224047 reported by Chemical Abstracts, Vol. 112 (10):83303f reports a cobalt, iron or nickel catalyst containing silver as a co-catalyst for the decomposition of nitrogen oxides to molecular nitrogen without the addition of ammonia.
While improved efficiencies of conversion to ethylene oxide are desirable, the typical concomitant increase in temperature (i.e., loss of activity) can be troublesome for a commercially-viable catalyst. Commercial ethylene oxide plants are typically operated to provide a desired balance of productivity and efficiency. Less active catalysts are thus operated at higher temperatures to achieve desired productivity. However, the upper temperature range of the catalyst is limited. Consequently, catalysts that have high initial temperatures for a given conversion rate may have shorter useful lives. Not only is catalyst a major expense to the ethylene oxide plant owner, but also, the plant must be shut down for substantial periods of time to discharge the old catalyst and charge new catalyst to the typical tubular, fixed bed ethylene oxide reactors. Hence, without a useful lifetime, e.g., two years or more, the benefit of any enhanced efficiency is quickly lost in catalyst replacement costs and plant shut-down time. Thus, the activity stability and/or efficiency stability of a catalyst are important concerns in achieving a commercially viable ethylene oxide catalyst.
Cobalt has been proposed for other silver-containing catalysts. For instance, Japanese patent application Kokai 57/13691 discloses a silver-cobalt oxide-manganese dioxide catalyst for ozone decomposition. British patent application 2,095,242 discloses a process for the oxychlorination of olefins using a catalyst comprising metallic silver and/or a compound thereof and one or more compounds of manganese, cobalt or nickel.
Methods are sought to enhance the activity and, in particular, the activity stability and/or efficiency stability of silver-containing, supported ethylene oxide catalysts which have been promoted to enhance efficiency, which while providing desirable efficiencies, are typically less active and must be operated at higher temperatures to be useful in commercial production facilities. These high temperatures can unduly shorten the catalyst life such that the catalysts are unattractive for commercial facilities. Catalysts with enhanced activity stability and/or efficiency stability would be very advantageous.
By this invention silver-containing, supported alkylene oxide catalysts suitable for the epoxidation of alkene to alkylene oxide are provided that have enhanced activity and/or efficiency and/or stability. The catalysts contain deposited thereon a sufficient amount of at least one cobalt component to increase at least one of the activity and/or efficiency and/or stability of the catalyst as compared to a similar catalyst which does not contain the cobalt component under otherwise identical conditions. Often, the cobalt component is present in an amount of at least about 10 or 20, e.g., about 25 to 1000, preferably about 50 to 500, ppm (weight) calculated as the weight of cobalt based on the total weight of the catalyst. The amount of cobalt which provides the enhanced activity and/or efficiency and/or stability generally varies depending on the nature and amounts of other components in the catalyst composition.
When the activity of a catalyst is enhanced, the temperature required to produce, under given conditions, a given level of alkylene oxide (usually expressed in terms of increase in alkylene oxide concentration across the catalyst bed) is reduced. The stability of a catalyst can be with respect to at least one of efficiency aging rate and activity aging rate. In a more stable catalyst, the efficiency aging rate and/or activity aging rate is less than that in a less stable catalyst. An especially beneficial attribute of the catalysts of this invention is an enhanced efficiency stability during the epoxidation process. By enhanced efficiency stability is meant that the selectivity of the catalyst to the production of alkylene oxide does not decrease as rapidly over time of operation as would a similar catalyst but which does not contain the cobalt component at identical operating conditions.
Preferred epoxidation systems for use of the catalysts of this invention are the systems in which the catalysts comprise at least one efficiency-enhancing salt of a redox-half reaction pair in conjunction with at least one gaseous efficiency-enhancing member of a redox-half reaction pair. In these systems, the efficiency stabilizing effect of the cobalt component is often most pronounced.
As used herein, the term xe2x80x9ccompoundxe2x80x9d refers to the combination of a particular element with one or more different elements by surface and/or chemical bonding, such as ionic and/or covalent and/or coordinate bonding. The term xe2x80x9cionicxe2x80x9d or xe2x80x9cionxe2x80x9d refers to an electrically charged chemical moiety; xe2x80x9ccationicxe2x80x9d or xe2x80x9ccationxe2x80x9d being positive and xe2x80x9canionicxe2x80x9d or xe2x80x9canionxe2x80x9d being negative. The term xe2x80x9coxyanionicxe2x80x9d or xe2x80x9coxyanionxe2x80x9d refers to a negatively charged moiety containing at least one oxygen atom in combination with another element. An oxyanion is thus an oxygen-containing anion. It is understood that ions do not exist in vacuo, but are found in combination with charge-balancing counter ions.
The catalyst contains at least one other promoter in an amount sufficient to enhance the efficiency of the catalyst as compared to a similar catalyst but which does not contain the promoter. Often, the promoter comprises a compound of an element other than cobalt which is selected from Groups 1a and/or 2a and/or from Groups 3b through 7b, inclusive, and 3a through 7a, inclusive, of the Periodic Table. (References to the Periodic Table herein shall be to that as published by the Chemical Rubber Company, Cleveland, Ohio, in CRC Handbook of Chemistry and Physics, 46th Edition, inside back cover.) The preferred anionic promoters include the oxyanions of the elements other than oxygen having an atomic number of 5 to 83 of Groups 3b through 7b, inclusive, and 3a through 7a, inclusive, of the Periodic Table. More preferably, the promoters are one or more of the oxyanions of nitrogen, sulfur, tantalum, molybdenum, tungsten and rhenium, still more preferably one or more of the oxyanions of nitrogen, sulfur and rhenium. Many of these anionic promoters are characterized as both increasing efficiency and reducing activity of the catalysts.
In a preferred aspect of the invention, the catalyst comprises alkali metal nitrate, especially potassium and/or rubidium nitrate, especially in amounts greater than about 400 or 500 parts per million (ppm) by weight based on the weight of catalyst. In this aspect of the invention, a nitrogen and oxygen-containing compound, e.g., nitrogen oxide, nitrogen dioxide, nitrous oxide, etc., may be introduced into the reaction zone containing the catalyst as a co-promoter to enhance at least one of activity, efficiency and stability of the catalyst performance.
An aspect of this invention relates to the use of the aforementioned catalysts in epoxidizing alkene to alkylene oxide, especially ethylene to ethylene oxide.
Alkylene oxides made using the catalysts of this invention are characterized by the structural formula
wherein R1 and R2 are lower alkyl, e.g., methyl or ethyl or, preferably, hydrogen. Most preferably the alkylene oxide is ethylene oxide. The alkylene oxides are made from the corresponding alkene, i.e., R1HCxe2x95x90CHR2. For purposes of ease of understanding, the following discussion will be made with reference to ethylene oxide and ethylene.
The catalysts of this invention are characterized by combining a sufficient amount of at least one cobalt component to enhance the activity and/or efficiency and/or stability of the catalyst as compared to a similar catalyst which does not contain the cobalt component. Although the catalysts can be used under widely varying process conditions, for purposes of determining whether sufficient cobalt component has been incorporated into the catalyst, a standard set of process conditions can be used.
The STANDARD ETHYLENE OXIDE PROCESS CONDITIONS (ABBR. xe2x80x9cCONDITIONSxe2x80x9d) for characterizing the catalysts of this invention involve the use of a standard backmixed autoclave with full gas recycle including carbon dioxide. The CONDITIONS may be operated with some variation in ethylene, oxygen and gas phase inhibitor feed. Two cases are illustrated: air process conditions, which simulates in the backmixed reactor the typical conditions employed in commercial air-type ethylene oxide processes where air is used to supply the molecular oxygen and the oxygen process conditions, which simulates in the backmixed reactor the typical conditions in commercial oxygen-type ethylene oxide processes where molecular oxygen, as such, is employed. Each case provides a different efficiency but it is the rule for practically all cases that with air as the oxygen feed, using lower amounts of oxygen and ethylene will yield an efficiency to ethylene oxide which is about 2 to 4 percentage points lower than that when molecular oxygen is employed as oxygen feed. When the catalyst contains a redox-half reaction pair salt and is intended to be used in conjunction with the corresponding efficiency-enhancing gaseous member of a redox-half reaction pair, the CONDITIONS provide for the presence of such gaseous member. The CONDITIONS employ 2.0 mole % ethylene oxide in the outlet gas of the reactor under the following standard inlet conditions:
The CONDITIONS employ the well known backmixed bottom-agitated xe2x80x9cMagnedrivexe2x80x9d autoclaves described in FIG. 2 of the paper by J. M. Berty entitled xe2x80x9cReactor for Vapor Phase-Catalytic Studiesxe2x80x9d, in Chemical Engineering Progress, Vol. 70, No. 5, pages 78-84, 1974.
The pressure is maintained constant at 275 psig and the total outlet flow is maintained at 22.6 SCFH. SCFH refers to cubic feet per hour at standard temperature and pressure, namely, 0xc2x0 C. and one atmosphere. The outlet ethylene oxide concentration is maintained at 2.0% by adjusting the reaction temperature. Thus temperature (xc2x0C.) and catalyst efficiency are obtained as the responses describing the catalyst performance.
The catalyst test procedure used in the CONDITIONS involves the following steps:
1. 80 cc of catalyst are charged to the backmixed autoclave. The volume of catalyst is measured in a 1 inch I.D. graduated cylinder after tapping the cylinder several times to thoroughly pack the catalyst. The volume of catalyst is alternatively calculated from the packing density of the carrier and the amount of silver and additives. The weight of the catalyst is noted.
2. The backmixed autoclave is heated to about reaction temperature in a nitrogen flow of 20 SCFH with the fan operating at 1500 rpm. The nitrogen flow is then discontinued and the above-described feed stream is introduced into the reactor. The total gas outlet flow is adjusted to 22.6 SCFH. The temperature is set at 220xc2x0 C.
3. The temperature is raised over the next three days to 255xc2x0 C. The selectivity and the activity of the catalyst to ethylene oxide are thus obtained.
The standard deviation of a single test result reporting catalyst efficiency in accordance with the procedure described above is about 0.7% efficiency units. The standard deviation of a single test result reporting catalyst activity in accordance with the procedure described above is about 0.03 mole % ethylene oxide. The standard deviation, of course, will depend upon the quality of the equipment and precision of the techniques used in conducting the tests, and thus will vary. The test results reported herein are believed to be within the standard deviation set forth above. The running of a multiplicity of tests will reduce the standard deviation by the square root of the number of tests.
The activity stability and efficiency stability of a catalyst is conveniently determined under the CONDITIONS. The rate of decrease in activity and efficiency with time is indicative of the activity stability and efficiency stability of the catalyst. Usually, the study is conducted for about 50 days with a delta ethylene oxide concentration across the catalyst of about 2 mole percent. The time to provide an indication of stability may be 20 or 30 days at ethylene oxide production rates of about 2 mole percent.
The amount of cobalt component is generally sufficient to provide an increase in efficiency stability under CONDITIONS of at least about 0.5, preferably at least about 1, efficiency percentage point after 50 days of operation. Most desirably, oxygen process conditions are used. In determining the enhancement in efficiency stability, the process and catalyst should be under steady state conditions. In some instances, the catalyst activates over a period of time, even as much as a week or more, before the catalyst reaches peak initial activity. The reason for this period of activation in some catalysts is not known and may be due to chemical and/or physical conditioning of the catalyst. Therefore, the initial activity of a catalyst is usually determined after the catalyst has been on-stream for at least about 24, preferably for at least about 120 to 170, hours.
The optimal amount of the cobalt component may vary with silver content, the amounts and types of other promoters present and the chemical and physical properties of the carrier. However, the cobalt component is often present in an amount of at least about 10, preferably at least about 25, ppmw (parts per million by weight) calculated as the weight of cobalt on the total catalyst. If too much cobalt component is used, the catalyst performance, e.g., efficiency and/or activity and/or stability, may suffer. If too little cobalt component is present, it is also possible that the performance of the catalyst will suffer or the amount present will be insufficient to show the desired catalytic effect. In determining desired amounts of cobalt component, a traverse of cobalt component concentrations in the catalyst composition can be effected with the catalysts being evaluated for performance. In some instances, it may be desirable to vary the amounts of other components, e.g., silver and other promoters, to achieve beneficial combinations of effects and optimal catalyst performances. Usually, the amount of cobalt component falls within the range of about 25 to 1000, preferably, about 50 to 500, ppmw calculated as the weight of cobalt.
The cobalt component can be provided in various forms, e.g., as a covalent compound such as cobalt oxide, as a cation or as an anion. The specific one or more cobalt species that provide enhanced activity and/or efficiency and/or stability are not certain and may be the component added and/or that generated during catalyst preparation or during use as a catalyst. Although the cobalt species that provide the beneficial properties to the catalysts are not known with specificity, suitable results are obtained when the cobalt component is added to the catalyst in the form of a cation, e.g., cobalt nitrate. The cobalt may be in the +2 oxidation state or +3 oxidation state when added.
Cobalt components include, but are not limited to, cobaltous oxide, cobaltic oxide, cobaltous nitrate, cobaltic nitrate, cobaltous nitrite, cobaltic nitrite, cobaltous sulfate, cobaltic sulfate, cobaltous acetate, cobaltic acetate, cobaltous citrate, cobaltic citrate, cobaltous lactate, cobaltic lactate, cobaltous oxalate, cobaltic oxalate, cobaltous chloride, cobaltic chloride, ammonium cobaltate, cesium cobaltate, potassium cobaltate, sodium cobaltate, cobalt (II) complexes, cobalt (III) complexes and the like. Examples of complexing agents useful in forming the cobalt complexes include ethylenediaminetetraacetic acid (EDTA); N,Nxe2x80x2-ethylenediaminediacetic acid; N-hydroxyethylethylenediaminetriacetic acid; diethylenetriaminepentaacetic acid; nitrilotriacetic acid; N-hydroxyethyl-iminodiacetic acid; N-dihydroxyethylglycine; etc . . . Mixtures of cobalt-containing compounds may be used.
As with any catalyst for making ethylene oxide which provides optimum performance, a correlation exists among many factors. Factors frequently considered include:
(i) the nature of the support;
(ii) the amount of silver on or in the support;
(iii) the components and amounts thereof in or on the support;
(iv) the impurities or contaminants provided with the silver or other components;
(v) the procedure to make the catalyst; and
(vi) the conditions under which the catalyst is used to produce ethylene oxide.
However, in attempting to define any catalyst, there must be a base value from which other factors are determined especially when the factors are variables, each dependent upon the base value for meaning. In the case of this invention, the base value can be the amount of silver or a combination of the amount of silver and the nature of the support. In most cases the latter combination will be the base value. Because at least two values will comprise the base value for catalyst performance, it is apparent that correlations between such combinations and other factors can be quite complex. There is no common thread of logic which integrates all of these combinations and/or factors. To that extent, practice of the invention requires experimental efforts to achieve all or essentially all of the benefits of this invention. without departing from this script, one skilled in the art can readily achieve the optimum performances of the catalysts of this invention. It should be recognized that such script is commonly followed by the artisan in making any commercially-employable ethylene oxide catalyst. The elements of the script are dependent upon the technology employed in making the catalyst.
The concentration of silver in the finished catalyst may vary from about 2 to 45 or more, often about 2 to 40 or more, weight percent, a commercially preferred range being from about 6% to about 35% by weight of silver. Lower silver concentrations are preferred from an economic standpoint. However, the optimum silver concentration for any particular catalyst will be dependent upon economic factors as well as performance characteristics, such as catalyst efficiency, rate of catalyst aging and reaction temperature.
The support or carrier employed in these catalysts in its broadest aspects is selected from the large number of porous refractory catalyst carriers or support materials which are considered relatively inert in the presence of the ethylene epoxidation feeds, products and reaction conditions. Many such materials are known to persons skilled in the art and may be of natural or synthetic origin and preferably are of a macroporous structure.
The chemical composition of the carrier is not narrowly critical. Carriers may be composed, for example, of alpha-alumina, silicon carbide, silicon dioxide, zirconia, magnesia and various clays. The preferred carriers are alpha-alumina particles often bonded together by a bonding agent and have a very high purity, i.e., at least 98 wt. % alpha-alumina, any remaining components being silica, alkali metal oxides (e.g., sodium oxide) and trace amounts of other metal-containing and/or non-metal-containing additives or impurities; or they may be of lower purity, e.g., about 80 wt. % alpha-alumina, the balance being a mixture of silicon dioxide, various alkali oxides, alkaline earth oxides, iron oxides, and other metal and non-metal oxides. The carriers are formulated so as to be inert under catalyst preparation and reaction conditions. A wide variety of such carriers are commercially available. Alumina carriers are manufactured by United Catalysts, Inc., Louisville, Ky., and the Norton Company, Akron, Ohio.
In the case of alpha alumina-containing supports, preference is given to those having a specific surface area as measured by the B.E.T. method of from about 0.03 m2/g to about 10 m2/g, preferably from about 0.05 m2/g to about 5 m2/g, more preferably from about 0.1 m2/g to about 3 m2/g, and a water pore volume as measured by conventional water absorption techniques of from about 0.1 to about 0.85 cc/g by volume. The B.E.T. method for determining specific surface area is described in detail in Brunauer, S., Emmet, P. and Teller, E. J. Am. Chem. Soc., 60, 309-16 (1938).
Certain types of alpha alumina-containing supports are particularly preferred. These alpha alumina supports have relatively uniform pore diameters and are more fully characterized by having (1) B.E.T. specific surface areas of from about 0.1 m2/g to about 3.0 m2/g, preferably about 0.1 m2/g to about 2.0 m2/g and (2) water pore volumes of from about 0.10 cc/g to about 0.85 cc/g, preferably from about 0.25 cc/g to about 0.75 cc/g. Median pore diameters for the above-described carriers range from about 0.01 to 100 microns, a more preferred range being from about 0.5 to 50 microns. The carriers may have monomodal, bimodal or multimodal pore distributions. Typical properties of some supports found in the literature are shown in Table I.
Regardless of the character of the support or carrier used, it is preferably shaped into particles, chunks, pieces, pellets, rings, spheres, wagon wheels, cross-partitioned hollow cylinders (or rings), and the like of a size suitable for employment in fixed bed reactors. Conventional commercial fixed bed ethylene oxide reactors are typically in the form of a plurality of parallel elongated tubes (in a suitable shell) approximately 0.7 to 2.7 inches O.D. and 0.5 to 2.5 inches I.D. and 15-45 feet long filled with catalyst. In such reactors, it is desirable to employ a support formed into a rounded shape, such as, for example, spheres, pellets, rings, cross-partitioned rings, tablets and the like, having diameters from about 0.1 inch to about 0.8 inch.
As with any supported catalyst, the optimal performance will depend upon optimizing the carrier in terms of its chemical composition (including impurities), surface area, porosity and pore volume. However, the enhancement in performance provided by this invention may be most pronounced when using less than optimized carriers. Thus, in demonstrating the invention in the examples, a variety of carriers are used.
The catalysts of this invention contain, in addition to the cobalt component, at least one other promoter or modifier to enhance the performance of the catalyst, e.g., to enhance efficiency and/or reduce the burning of ethylene oxide and/or affect activity. These promoters or modifiers are generally provided as chemical compounds.
For the sake of ease of understanding, the promoters will be referred to in terms of cation promoters, e.g., alkali and alkaline earth metals, and anion promoters. Compounds such as alkali metal oxide or MoO3, while not being ionic, may convert to ionic compounds, e.g., during catalyst preparation or in use. Whether or not such a conversion occurs, they will be referred to herein in terms of cation and anion species, e.g., alkali metal or molybdate.
Frequently, the catalyst contains alkali metal and/or alkaline earth metal as cationic promoter. Exemplary of the alkali metal and/or alkaline earth metals are lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium and barium. Other cationic promoters include Group 3b metal ions including scandium, yttrium, lanthanum and the lanthanide series metals. In some instances, the promoter comprises a mixture of cations, e.g., cesium and at least one other alkali metal, to obtain a synergistic efficiency enhancement as described in British Patent No. 2,043,481 discussed above. The cation promoter may, of course, provide the counter ion to a cobaltate anion component. Cesium salts alone or in combination with other salts are often used.
In many instances, the catalyst preferably comprises salt(s) of at least one oxyanion of an element (other than oxygen) having an atomic number of 5 to 83 and being from groups 3b through 7b, inclusive, and groups 3a through 7a, inclusive, of the Periodic Table. In some instances, it has been found beneficial to add more anion than is required to associate with the total alkali metal and alkaline earth metal being provided to the catalyst. The reason why such additional anion is beneficial in these situations is not known. The additional anion may be added in the form of an acid, an ammonium salt, an amine salt, etc., or a portion of the alkali metal and/or alkaline earth metal may be added as an acid salt, e.g., cesium hydrogen sulfate.
The concentration of the salt(s) (including any other alkali metal and alkaline earth metal salts) in the finished catalyst is not narrowly critical and may vary over a wide range. The optimum salt concentration for a particular catalyst will be dependent upon performance characteristics, such as, catalyst efficiency, rate of catalyst aging and reaction temperature.
The concentration of salt (based on the weight of the cation, e.g., cesium) in the finished catalyst may vary from about 0.0005 to 1.0 weight percent, preferably from about 0.005 to 0.5 weight percent. The preferred amount of cation promoter deposited on or present on the surface of the carrier or catalyst generally lies between about 10 and about 4000, preferably about 15 and about 3000 and more preferably between about 20 and about 2500 ppm by weight of cation calculated on the total carrier material. Amounts between about 50 and about 2000 ppm are frequently most preferable. When cesium is used in mixture with other cations, the ratio of cesium salt to any other alkali metal and alkaline earth metal salt(s), if used, to achieve desired performance is not narrowly critical and may vary over a wide range. The ratio of cesium salt to the other salt(s) may vary from about 0.0001:1 to 10,000:1, preferably from about 0.001:1 to 1,000:1. Preferably, cesium comprises at least about 10, more preferably, about 20 to 100, percent (weight) of the total added alkali metal and alkaline earth metal in the finished catalyst.
In some preferred embodiments of this invention especially when using other than a redox pair catalyst, the amount of leachable potassium cation as determined by leaching in a mineral acid, particularly nitric acid in a concentration of about 10 percent by volume at a temperature of about 90xc2x0 C. for about 1 hour followed by washing with distilled water, is less than about 50, preferably less than about 25, e.g., 0 to about 25, ppmw based on the weight of the catalyst. In some instances, the low level of leachable potassium appears, in combination with the cobalt component, to enhance or to permit the cobalt component to achieve greater enhancement of the activity and/or stability of the catalyst. Also, in many instances, preferred embodiments of the catalysts of this invention contain less than about 100, e.g., less than about 50, ppmw of leachable sodium cation as determined by the above procedure.
The types of anion promoters or modifiers suitable for use in the catalysts of this invention comprise, by way of example only, oxyanions such a sulfate, SO4xe2x88x922, phosphates, e.g., PO4xe2x88x923, titanates, e.g., TiO3xe2x88x922, manganates, e.g., MnO2xe2x88x92, tantalates, e.g., Ta2O6xe2x88x922, molybdates, e.g., MoO4xe2x88x922, vanadates, e.g., V2O4xe2x88x922, chromates, e.g., CrO4xe2x88x922, zirconates, e.g., ZrO3xe2x88x922, polyphosphates, nitrates, chlorates, bromates, borates, silicates, carbonates, tungstates, thiosulfates, cerates and the like. Halide ions may also be present as anions and include fluoride, chloride, bromide and iodide.
It is well recognized that many anions have complex chemistries and may exist in one or more forms, e.g., orthovanadate and metavanadate; and the various molybdate oxyanions such as MoO4xe2x88x922, Mo7O24xe2x88x926 and Mo2O7xe2x88x922. The oxyanions may also include mixed metal-containing oxyanions including polyoxyanion structures. For instance, manganese and molybdenum can form a mixed metal oxyanion. Similarly, other metals, whether provided in anionic, cationic, elemental or covalent form may enter into anionic structures.
While an oxyanion, or a precursor to an oxyanion, may be used in solutions impregnating a carrier, it is possible that during the conditions of preparation of the catalyst and/or during use, the particular oxyanion or precursor initially present may be converted to another form. Indeed, the element may be converted to a cationic or covalent form. Preferably, the element is associated with oxygen, i.e., is an oxyanion, a covalent oxide or has an oxygen-containing anion. In many instances, analytical techniques may not be sufficient to precisely identify the species present. The invention is not intended to be limited by the exact species that may ultimately exist on the catalyst during use but rather reference herein to oxyanions is intended to provide guidance to understanding and practicing the invention.
Anion promoters include, but are not limited to, the sulfates and oxyanions of rhenium, molybdenum, tungsten and/or chromium. Examples of anions of sulfur that can be suitably applied include sulfate, sulfite, bisulfite, bisulfate, sulfonate, persulfate, thiosulfate, dithionate, dithionite, halosulfate, e.g., fluorosulfate, etc. Preferred compounds to be applied are ammonium sulfate and the alkali metal sulfates. Examples of anions of molybdenum, tungsten and chromium that can be suitably applied include molybdate, dimolybdate, paramolybdate, other iso- and heteropolymolybdates, etc.; tungstate, paratungstate, metatungstate, other iso- and hetero-polytungstates, etc.; and chromate, dichromate, chromite, halochromate, etc. Preferred are sulfates, molybdates, tungstates and chromates.
When the catalyst comprises rhenium, the rhenium component can be provided in various forms, e.g., as the metal, as a covalent compound, as a cation or as an anion. The rhenium species that provides the enhanced efficiency and/or activity is not certain and may be the component added or that generated either during preparation of the catalyst or during use as a catalyst. Examples of rhenium compounds include the rhenium salts such as rhenium halides, the rhenium oxyhalides, the rhenates, the perrhenates, the oxides and the acids of rhenium. However, the alkali metal perrhenates, alkaline earth metal perrhenates, silver perrhenates, other perrhenates and rhenium heptoxide can also be suitably utilized. Rhenium heptoxide, Re2O7, when dissolved in water, hydrolyzes to perrhenic acid, HReO4, or hydrogen perrhenate. Thus, for purposes of this specification, rhenium heptoxide can be considered to be a perrhenate, i.e., ReO4. Similar chemistries can be exhibited by other metals such as molybdenum and tungsten.
The amount of anion promoter may vary widely, e.g., from about 0.0005 to 2 weight percent, preferably from about 0.001 to 0.5 weight percent based on the total weight of the catalyst. When used, the rhenium component is often provided in an amount of at least about 1, say, at least about 5, e.g., about 10 to 2000, often between about 20 and 1000, ppmw calculated as the weight of rhenium based on the total weight of the catalyst.
Another class of promoters includes manganese components. In many instances, manganese components can enhance the activity and/or stability of catalysts. The manganese species that provides the enhanced activity and/or stability is not certain and may be the component added or that generated either during catalyst preparation or during use as a catalyst. Manganese components include, but are not limited to, manganese acetate, manganese ammonium sulfate, manganese citrate, manganese dithionate, manganese oxalate, manganous nitrate, manganous sulfate, and manganate anion, e.g., permanganate anion, manganate anion, manganese complexes, e.g., with manganese in the +2 or +3 oxidation state and complexed with a complexing agent, such as a complexing agent selected from those set forth elsewhere herein, and the like. When used, the manganese component is often provided in an amount of at least about 1, say, at least about 5, e.g., about 10 to 2000, or about 20 to 1000, ppmw calculated as the weight of manganese based on the total weight of the catalyst.
The catalysts of this invention may be of the type comprising at least one efficiency-enhancing salt of a member of a redox-half reaction pair which are intended to be employed in epoxidation processes in which at least one efficiency-enhancing gaseous member of a redox-half reaction pair is present (described hereinbelow). The term xe2x80x9credox-half reactionxe2x80x9d is defined herein to mean half-reactions like those found in equations presented in tables of standard reduction or oxidation potentials, also known as standard or single electrode potentials, of the type found in, for instance, xe2x80x9cHandbook of Chemistryxe2x80x9d, N. A. Lange, Editor, McGraw-Hill Book Company, Inc., pages 1213-1218 (1961) or xe2x80x9cCRC Handbook of Chemistry and Physicsxe2x80x9d, 65th Edition, CRC Press, Inc., Boca Raton, Fla., pages D155-162 (1984). The term xe2x80x9credox-half reaction pairxe2x80x9d refers to the pairs of atoms, molecules or ions or mixtures thereof which undergo oxidation or reduction in such half-reaction equations. Such terms as redox-half reaction pairs are used herein to include those members of the class of substances which provide the desired performance enhancement, rather than a mechanism of the chemistry occurring. Preferably, such compounds, when associated with the catalyst as salts of members of a half reaction pair, are salts in which the anions are oxyanions, preferably an oxyanion of a polyvalent atom; that is, the atom of the anion to which oxygen is bonded is capable of existing, when bonded to a dissimilar atom, in different valence states. Potassium is the preferred cation, although sodium, rubidium and cesium may also be operable, and the preferred anions are nitrate, nitrite and other anions capable of undergoing displacement or other chemical reaction and forming nitrate anions under epoxidation conditions. Preferred salts include KNO3 and KNO2, with KNO3 being most preferred.
The salt of a member of a redox-half reaction pair is added in an amount sufficient to enhance the efficiency of the epoxidation reaction. The precise amount will vary depending upon such variables as the gaseous efficiency-enhancing member of a redox-half reaction used and concentration thereof, the concentration of other components in the gas phase, the amount of silver contained in the catalyst, the surface area of the support, the process conditions, e.g., space velocity and temperature, and morphology of support. Generally, however, a suitable range of concentration of the added efficiency-enhancing salt, calculated as cation, is about 0.01 to about 5 percent, preferably about 0.02 to about 3 percent, by weight, based on the total weight of the catalyst. Most preferably the salt is added in an amount of about 0.03 to about 2 weight percent.
In any event, each promoter, such as each metal-containing promoter, e.g., whether cationic, anionic or nonionic, is provided in a promoting amount. As used herein the term xe2x80x9cpromoting amountxe2x80x9d of a certain component of a catalyst refers to an amount of that component that works effectively to provide an improvement or enhancement in one or more of the catalytic properties of that catalyst when compared to a catalyst not containing said component. Examples of catalytic properties include, inter alia, operability (resistance to run-away), selectivity, activity, conversion, stability and yield. It is understood by one skilled. in the art that one or more of the individual catalytic properties may be enhanced by the xe2x80x9cpromoting amountxe2x80x9d while other catalytic properties may or may not be enhanced or may even be diminished. Indeed, the promoter may enhance efficiency but decrease activity of the catalyst as determined under Standard Ethylene Oxide Process Conditions. It is further understood that different catalytic properties may be enhanced at different operating conditions. For example, a catalyst having enhanced selectivity at one set of operating conditions may be operated at a different set of conditions wherein the improvement shows up in the activity rather than the selectivity and an operator of an ethylene oxide plant will intentionally change the operating conditions in order to take advantage of certain catalytic properties even at the expense of other catalytic properties in order to maximize profits by taking into account feedstock costs, energy costs, by-product removal costs and the like.
The promoting effect provided by the promoters can be affected by a number of variables such as for example, reaction conditions, catalyst preparative techniques, surface area and pore structure and surface chemical properties of the support, the silver and co-promoter content of the catalyst, and the presence of other cations and anions present on the catalyst. The presence of other activators, stabilizers, promoters, enhancers or other catalyst improvers can also affect the promoting effects.
A variety of procedures may be employed for preparing catalysts in accordance with the present invention. The preferred procedure comprises: (1) impregnating a porous catalyst carrier with a solution comprising a solvent or solubilizing agent, silver complex and any promoter or promoters in amounts sufficient to deposit the desired weight of silver and the aforementioned promoter or promoters upon the carrier, and (2) thereafter treating the impregnated support to convert the silver salt to silver metal and effect deposition of silver and the promoter or promoters onto the exterior and interior surfaces of the support. For sake of repeatability, in the use and reuse of impregnating solutions the carrier should preferably not contain undue amounts of ions which are soluble in the impregnating solution and/or exchangeable with the promoter or promoters supplied to the catalyst, either in the preparation or use of the catalyst, so as to upset the amount of promoter which provides the desired catalyst enhancement. If the carrier contains such ions, the ions should generally be removed by standard chemical techniques such as leaching. Silver and promoter depositions are generally accomplished by heating the carrier at elevated temperatures to evaporate the remaining liquid within the support and effect deposition of the silver and promoter or promoters onto the interior and exterior carrier surfaces. Impregnation of the carrier is the preferred technique for silver deposition because it utilizes silver more efficiently than coating procedures, the latter being generally unable to effect substantial silver deposition onto the interior surface of the carrier. In addition, coated catalysts are more susceptible to silver loss by mechanical abrasion.
The sequence of impregnating or depositing the surfaces of the carrier with silver and promoters is optional. Thus, impregnation and deposition of silver and salts may be effected coincidentally or sequentially, i.e., the promoters may be deposited prior to, during, or subsequent to silver addition to the carrier. The promoters may be deposited together or sequentially. For example, one or more of the salts may be deposited first followed by the coincidental or sequential deposition of silver and additional or other salts. In instances in which the silver component in the silver impregnation solution may interfere with the compound providing the promoter, or, alternatively, the compound providing the promoter may interfere with the silver component in the impregnation solution, it is frequently desirable to use a sequential deposition process in which the silver is deposited and calcined and then the promoter compound is impregnated onto the support.
Impregnation of the catalyst carrier is effected using one or more solutions containing silver and promoters in accordance with well-known procedures for coincidental or sequential depositions. For coincidental deposition, following impregnation the impregnated carrier is heat or chemically treated to reduce the silver compound to silver metal and deposit the salts onto the catalyst surfaces.
For sequential deposition, the carrier is initially impregnated with silver or promoter (depending upon the sequence employed) and then heat or chemically treated as described above. This is followed by a second impregnation step and a corresponding heat or chemical treatment to produce the finished catalyst containing silver and promoters.
In one useful embodiment, the silver-containing carrier is subsequently impregnated using a solution containing a metal-containing promoter other than alkali metals or alkaline earth metals, the solution being chosen so that the metal-containing promoter has an increased affinity to the silver-containing carrier relative to its affinity to the carrier without silver and/or is associated with, preferably adsorbed on and more preferably deposited on, the silver-containing carrier at an increased rate relative to the rate at which the promoter would be associated with the carrier without silver. This method facilitates catalyst preparation and produces catalysts which are effective for alkene epoxidation. This method is more fully described in commonly assigned U.S. patent application Ser. No. 07/596,228, filed Oct. 12, 1990 now U.S. Pat. No. 5,112,795, which is incorporated in its entirety herein by reference.
In making the catalysts of this invention, some promoters such as some alkali and alkaline earth metal salts have such high melting temperatures that when deposited on the support with silver compound, and subjected to heating to convert the silver compound to silver metal, the salts may remain essentially unchanged. Of course, it is realized that alkali metal and alkaline earth metal salts having an unstable oxidation state will change to a stable oxidation state or states, e.g., sulfites to sulfates. When, for instance, the alkali metal or alkaline earth metal is deposited as the hydroxide or carbonate, it may be transformed in the presence of amines, which may be used in the impregnation of the catalyst, to a different salt form (i.e., nitrate) during the heating (roasting) step depending on the roast conditions.
The silver solution used to impregnate the carrier is comprised of a silver compound in a solvent or complexing/solubilizing agent such as the silver solutions disclosed in the art. The particular silver compound employed may be chosen, for example, from among silver complexes, nitrate, silver oxide or silver carboxylates, such as silver acetate, oxalate, citrate, phthalate, lactate, propionate, butyrate and higher fatty acid salts. Desirably, silver oxide complexed with amines is the preferred form of silver in the practice of the invention.
A wide variety of solvents or complexing/solubilizing agents may be employed to solubilize silver to the desired concentration in the impregnating medium. Among those disclosed in the art as being suitable for this purpose are lactic acid (U.S. Pat. No. 2,477,436 to Aries; and U.S. Pat. No. 3,501,417 to DeMaio); ammonia (U.S. Pat. No. 2,463,228 to West, et al.); alcohols, such as ethylene glycol (U.S. Pat. No. 2,825,701 to Endler, et al.,; and U.S. Pat. No. 3,563,914 to Wattimina); and amines and aqueous mixtures of amines (U.S. Pat. No. 2,459,896 to Schwarz; U.S. Pat. No. 3,563,914 to Wattimina; U.S. Pat. No. 3,215,750 to Benisi; U.S. Pat. No. 3,702,259 to Nielsen; and U.S. Pat. Nos. 4,097,414, 4,374,260 and 4,321,206 to Cavitt).
The metal-containing promoter or promoters themselves may be present as complexes in the impregnating solution, in particular in such a solution which also contains silver, prior to being associated with the carrier. Such complexes may conveniently be derived by including one or more complexing agents effective to form a complex with at least one metal species, e.g., metal-containing promoter precursor, in the impregnating solution, or solution precursor (e.g., a liquid medium containing undissolved metal-containing promoter precursor) in an amount effective to enhance the solubility and/or solubility stability of the metal-containing promoter in the solution or solution precursor. The enhancement in solubility and/or solubility stability is determined by comparing similar impregnating solutions or solution precursors in which the metal-containing promoter is complexed and in which the metal-containing promoter is not complexed with the complexing agent and/or with and without the complexing agent. The term xe2x80x9csolubility stabilityxe2x80x9d is a measure of the ability of a metal-containing promoter to remain in solution over time, the longer the time the more solubility stable the metal-containing promoter is.
The complexing agent or agents useful to form the metal-containing promoter complexes thereof may be chosen, e.g., from among conventional and well known complexing agents, to provide the desired solubility and/or solubility stability. The selection of the particular complexing agent or agents to be employed is dependent on many factors, such as, the metal-containing promoter to be employed, the composition of the impregnation solution or solution precursor, the conditions at which the impregnation solution or solution precursor is to be held prior to being used to impregnate the carrier, etc. Examples of complexing agents which may be useful include ethylenediaminetetraacetic acid (EDTA); N,Nxe2x80x2-ethylenediaminediacetic acid; N-hydroxyethylethylenediaminetriacetic acid; diethylenetriaminepentaacetic acid; nitrilotriacetic acid; N-hydroxyethyl-iminodiacetic acid; N-dihydroxyethylglycine; etc . . .
The amount of complexing agent employed varies widely, for example, depending on the specific complexing agent and on the specific metal species to be complexed, and on the amount of metal to be complexed. Preferably, the amount of complexing agent is at least about 50%, more preferably at least about 100%, of that needed to form complexes with the metal species to be complexed in the impregnating solution or solution precursor. Excesses of complexing agent over that needed to form the desired complexes may be employed, for example, so that the complexes can be maintained over a relatively long period of time. For example, the complexing agent may be included in an amount of at least about 150% or at least about 200% or at least about 400% or more of that needed to form the desired complexes. The amount of the complexing agent employed, e.g., in the impregnating solution or solution precursor, includes both the complexing agent which is complexed with the metal species and the additional or excess complexing agent, if any, which is present in the impregnating solution or solution precursor and is not so complexed.
A particularly preferred process for making high silver content catalysts involves two or more sequential impregnations of silver, with or without promoters, each of which impregnations may be followed by roasting or other procedure to render the silver insoluble. Advantageously, the carrier has a high pore volume and surface area when using high silver loadings.
Following impregnation of the catalyst carrier with silver and/or promoter or promoters, the impregnated carrier particles are separated from any remaining non-absorbed solution. This is conveniently accomplished by draining the excess impregnating medium or, alternatively, by using separation techniques, such as filtration or centrifugation. The impregnated carrier is then generally heat treated (e.g., roasted) to effect decomposition and reduction of the silver metal compound (complexes in most cases) to metallic silver and/or the deposition of the promoter or promoters. Such roasting may be carried out at a temperature of from about 100xc2x0 C. to 900xc2x0 C., preferably from 200xc2x0 C. to 700xc2x0 C., for a period of time sufficient to convert substantially all of the silver salt to silver metal and/or to effect deposition of substantially all of the promoter or promoters. In general, the higher the temperature, the shorter the required time period. For example, at a temperature of from about 400xc2x0 C. to 900xc2x0 C., silver reduction may be accomplished in about 1 to 5 minutes. Although a wide range of heating periods have been suggested in the art to thermally treat the impregnated support, (e.g., U.S. Pat. No. 3,563,914 suggests heating for less than 300 seconds to dry, but not roast to reduce, the catalyst; U.S. Pat. No. 3,702,259 discloses heating from 2 to 8 hours at a temperature of from 100xc2x0 C. to 375xc2x0 C. to reduce the silver salt in the catalyst; and U.S. Pat. No. 3,962,136 suggests xc2xd to 8 hours for the same temperature range), it is only important that the time be correlated with temperature such that substantially complete reduction of the silver salt to metal and/or substantially complete deposition of the promoter or promoters are accomplished. A continuous or step-wise heating program is desirably used for this purpose. Continuous roasting of the catalyst for a short period of time, such as for not longer than xc2xd hour is preferred and can be effectively done in making the catalysts of this invention.
Heat treatment is preferably carried out in air, but a nitrogen or carbon dioxide atmosphere may also be employed. The equipment used for such heat treatment may use a static or flowing atmosphere of such gases to effect reduction, but a flowing atmosphere is much preferred.
An important consideration in making the catalyst of this invention is to avoid the use of strongly acidic or basic solutions which can attack the support and deposit impurities which can adversely affect the performance of the catalyst. The preferred impregnation procedure of U.K. Patent 2,043,481 coupled with the high roasting temperature, short residence time procedure which the patent also described is especially beneficial in minimizing such catalyst contamination. However, the use of the salts of this invention coupled with the high purity supports allows one to use lower temperatures though short residence times are preferred.
The particle size of silver metal deposited upon the carrier is asserted by a portion of the prior art to be a function of the catalyst preparation procedure employed. This may seem to be the case because of the limited ability of the art to effectively view the surface of the catalyst. Thus the space between the silver particles seen on the carrier has not been characterized sufficiently to say whether such particles of silver represent all the silver on the carrier. However, the particular choice of solvent and/or complexing agent, silver compound, heat treatment conditions and catalyst carrier may affect, to varying degrees, the range of the size of the resulting silver particles seen on the carrier. For carriers of general interest for the production of ethylene oxide, a distribution of silver particle sizes in the range of 0.005 to 2.0 microns is typically obtained. However, the role of particle size of the silver catalyst upon the effectiveness of the catalyst in making ethylene oxide is not clearly understood. In view of the fact that the silver particles are known to migrate on the surface of the catalyst when used in the catalytic reaction resulting in a marked change in their size and shape while the catalyst is still highly effective suggests that the silver particle size viewed on the support may not be a significant factor in catalytic performance.
The silver catalysts of the invention are particularly suitable for use in the production of ethylene oxide by the vapor phase oxidation of ethylene with molecular oxygen. The reaction conditions for carrying out the oxidation reaction are well-known and extensively described in the prior art. This applies to reaction conditions, such as temperature, pressure, residence time, concentration of reactants, gas phase diluents (e.g., nitrogen, methane and CO2), gas phase inhibitors (e.g., ethylene chloride and ethylene dichloride), and the like.
The gases fed to the reactor may contain modifiers or inhibitors or additives such as disclosed by Law, et al., in U.S. Pat. Nos. 2,279,469 and 2,279,470, such as nitrogen oxides and nitrogen oxides generating compounds. See also, European Patent No. 3642 which describes catalysts comprising at least one efficiency-enhancing salt of a redox-half reaction pair in conjunction with at least one gaseous efficiency-enhancing member of a redox-half reaction pair.
The terms xe2x80x9cgaseous member of a redox-half reaction pairxe2x80x9d, xe2x80x9cgaseous efficiency-enhancing member of a redox-half reaction pairxe2x80x9d, or like terms referred to herein have a meaning similar to that for the xe2x80x9csalt of a member of a redox-half reaction pairxe2x80x9d or like terms, defined above. That is, these terms refer to members of half-reactions, represented in standard or single electrode potential tables in standard reference texts or handbooks which are in a gaseous state and are substances which, in the reaction equations represented in the texts, are either oxidized or reduced. The preferred gaseous efficiency-enhancing materials are compounds containing an element capable of existing in more than two valence states, preferably nitrogen and another element which is, preferably, oxygen. Examples of preferred gaseous efficiency-enhancing members of redox-half reaction pairs include at least one of NO, NO2, N2O3, N2O4, N2O5 or any gaseous substance capable of forming one of the aforementioned gases, particularly NO and NO2, under epoxidation conditions, and mixtures thereof with one or more of PH3, CO, SO3, SO2, P2O5, and P2O3. NO is often preferred as the gaseous efficiency-enhancing compound.
Although in some cases it is preferred to employ members of the same half-reaction pair in the reaction system, i.e., both the efficiency-enhancing salt member associated with the catalyst and the gaseous member in the feedstream, as, for example, with a preferred combination of potassium nitrate and nitric oxide, this is not necessary in all cases to achieve satisfactory results. Other combinations, such as KNO3/N2O3, KNO3/NO2, KNO3/N2O4, KNO3/SO2, KNO2/NO, KNO2/NO2 and KNO3/a mixture of SO2 and NO, may also be employed in the same system. In some instances, the salt and gaseous members may be found in different half-reactions which represent the first and last reactions in a series of half-reaction equations of an overall reaction.
The gaseous efficiency-enhancing member of a redox-half reaction pair is also present in an amount sufficient to enhance the performance, such as the activity of the catalyst, and, particularly, the efficiency of the epoxidation reaction. The precise amount is determined, in part, by the particular efficiency-enhancing salt of a member of a redox-half reaction pair used and the concentration thereof, the particular alkene undergoing oxidation, and by other factors noted above which influence the amount of efficiency-enhancing salt of a member of a redox-half reaction pair. Typically a suitable concentration of the gaseous member of a redox-half reaction pair for epoxidation of most alkenes, including propylene, is about 0.1 to about 2,000 ppm, by volume, of the gaseous feedstream when N2 is used as ballast. When a preferred gaseous member of a redox-half reaction pair, such as NO, is used in the epoxidation of propylene, the preferred concentration is about 2,000 ppm, by volume, with an N2 ballast. However, when ethylene is being oxidized, a suitable concentration is from about 0.1 to about 100 ppm, by volume, of the gaseous feedstream components. Preferably, the gaseous efficiency-enhancing member of a redox-half reaction pair is present in an amount of about 1 to about 80 ppm when about 3 percent, by volume, CO2 is present in the reaction mixture. When nitric oxide is employed as the gaseous efficiency-enhancing compound in an ethylene epoxidation system, it is present in an amount of about 0.1 to about 60 ppm, preferably about 1 to about 40 ppm, when CO2 is present in the reaction mixture, e.g., in amounts up to about 3 volume percent.
The desirability of recycling unreacted feed, or employing a single-pass system, or using successive reactions to increase ethylene conversion by employing reactors in series arrangement can be readily determined by those skilled in the art. The particular mode of operation selected will usually be dictated by process economics.
Generally, the commercially-practiced processes are carried out by continuously introducing a feed stream containing ethylene and oxygen to a catalyst-containing reactor at a temperature of from about 200xc2x0 C. to 300xc2x0 C., and a pressure which may vary from about five atmospheres to about 30 atmospheres depending upon the mass velocity and productivity desired. Residence times in large-scale reactors are generally on the order of about 0.1-5 seconds. Oxygen may be supplied to the reaction in an oxygen-containing stream, such as air or as commercial oxygen. The resulting ethylene oxide is separated and recovered from the reaction products using conventional methods. However, for this invention, the ethylene oxide process envisions the normal gas recycle encompassing carbon dioxide recycle in the normal concentrations, e.g., about 0.5 to 6 volume percent.
The present cobalt-containing catalyst may be used selectively to enhance the effectiveness of an alkene epoxidation process, as described herein. For example, the present cobalt-containing catalyst may be effective to increase or enhance the rate of start-up of the alkene epoxidation process. In addition, the catalyst may provide increased catalyst effectiveness stability along the length of a fixed bed of catalyst relative to a similar catalyst which includes no cobalt component, e.g., at CONDITIONS. These features of the present cobalt-containing catalysts are more fully described in commonly assigned U.S. patent application Ser. No. 07/596,242 filed Oct. 12, 1990, now abandoned, which application is incorporated herein in its entirety by reference.
The specific STANDARD ETHYLENE OXIDE PROCESS CONDITIONS are used in the examples below unless indicated otherwise. In commercial processes, typical operating conditions can vary and the amounts of the ingredients employed can be adjusted to achieve the best efficiencies. In particular the amounts of ethane, carbon dioxide and organic chloride can be varied to optimize efficiency for the manufacture of ethylene oxide. Ethane is an impurity contained in varying amounts in ethylene raw material. Ethane can also be added to a commercial reactor to provide better control of the chloride""s inhibitor action. Typically, the amount of ethane used in commercial processes can vary from about 0.001 to about 5 mole percent for achieving optimization under both air process conditions and oxygen process conditions. As the concentration of ethane increases in the reactor, the effective surface chloride concentration on the catalyst is believed to be decreased thereby decreasing the ability of chloride to promote/inhibit reactions that increase efficiency for the manufacture of ethylene oxide. The amount of chloride, e.g., ethyl chloride or ethylene dichloride, can be varied to provide the needed promoter/inhibitor action commensurate with the ethane levels encountered in a particular process and the type of promoters or modifiers used in the catalyst. The amount of organic chloride used in commercial processes can typically vary from about 1.0 ppm to about 100 ppm for achieving optimization under both air process conditions and oxygen process conditions. Carbon dioxide is generally considered an inhibitor, and the inhibitor effect of carbon dioxide on process efficiency may be variable with its concentration. With different types of promoters or modifiers used in preparation of the catalysts of this invention, different concentrations of carbon dioxide may be more desirable in certain commercial processes. Typically, the amount of carbon dioxide used in commercial processes can vary from about 2 to about 15 mole percent for achieving optimization under both air process conditions and oxygen process conditions. The amount of carbon dioxide is dependent on the size and type of carbon dioxide scrubbing system employed. The optimization of the amounts of ethane, carbon dioxide and organic chloride provides catalysts which are especially suitable for obtaining desired efficiencies in commercial ethylene oxide manufacture. Especially in the epoxidation processes using at least one gaseous efficiency-enhancing member of a redox-half reaction pair in conjunction with at least one salt of a member of a redox-half reaction pair on the catalyst, the concentration of carbon dioxide is preferably maintained below about 1.5, e.g., below about 1.0 or even about 0.5, volume percent.
Catalysts which have been subjected to process conditions for ethylene oxide manufacture such as STANDARD ETHYLENE OXIDE PROCESS CONDITIONS are considered an important aspect of this invention.
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1. Field of the Invention
This invention relates to the field of dual stage actuated (DSA) suspensions for disk drives. More particularly, this invention relates to the field of electrical connections to microactuators on DSA suspensions.
2. Description of Related Art
Magnetic hard disk drives and other types of spinning media drives such as optical disk drives are well known. Disk drive suspensions are the assemblies that hold the read/write head over the correct place on the spinning data disk, in order to write data to, and read data from, the desired data track on the disk.
Both single stage actuated disk drive suspensions and dual stage actuated (DSA) suspension are known. In a single stage actuated suspension, only a voice coil motor moves the disk drive suspension. In a DSA suspension, as for example in U.S. Pat. No. 7,459,835 issued to Mei et al. as well as many others, in addition to the voice coil motor which moves the entire suspension, at least one secondary actuator, often referred to as a microactuator, is located on the suspension in order to effect fine movements of the magnetic head slider to keep it properly aligned over the data track on the spinning disk. The secondary DSA microactuator(s) provide much finer control and much higher bandwidth of the servo control loop than does the voice coil motor alone which effects relatively coarse movements of the suspension and hence the magnetic head slider. Lead zirconium titanate is one of the broadly used intermetallic inorganic compounds possessing piezoelectric properties and is commonly referred to as PZT. PZT devices are often used as the microactuator motor, although other types of microactuator motors are possible. Examples of a dual stage actuated suspension, a PZT microactuator often referred to simply as a PZT for short, and various methods of electrically and mechanically integrating the PZT into the suspension, are disclosed in U.S. Pat. No. 8,570,688 to Hahn, and in copending U.S. patent application Ser. No. 14/045,773, which are owned by the assignee of the present application. Other mechanical and electrical connections have been proposed.
Various structures and methods have been proposed for making the required electrical connections to the PZT microactuators. One structure and method that was developed by the assignee of the present application is shown in FIG. 1, and in FIG. 2 which is a cross sectional view taken of the suspension of FIG. 1 taken along section line 2-2. In this example, suspension 10 includes slider 12 mounted to gimbal 14. The PZT 20 is connected to gimbal 14 through gimbal arms 16. The PZT 20 typically includes PZT material 22, a thin top metalized electrode 24, and thin bottom metalized electrode 26. A flexible circuit 30 typically includes a metal support layer such as stainless steel layer 32, insulating layer such as polyimide layer 34, and a copper signal conductor layer including copper electrical contact pad 37 covered by an anti-corrosion layer 38 such as nickel followed by gold. Anti-corrosion layer 38 will be referred to hereafter simply as gold layer 38. Non-conductive adhesive such as non-conductive epoxy 50 physically attaches PZT 20 to the flexible circuit 30 on one side. For the electrical connection, bottom electrode 26 of PZT 20 is physically and electrically connected to the ground potential of the suspension body by conductive epoxy 18 bonded to grounded suspension body 16 which is stainless steel. The driving voltage potential is provided through conductive epoxy or solder balls 52 that forms a physical and electrical bridge from a copper contact pad 37 and its anti-corrosion layer 38 on the flexible circuit 30 to the metalized top surface of the PZT which defines the top electrode 24.
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Circuitized substrates such as printed circuit boards (hereinafter also referred to as PCBs), chip carriers, and the like typically are constructed in laminate form in which several layers of dielectric material and conductive material (laminates) are bonded together using relatively high temperature and pressure lamination processes. The conductive layers, typically of thin copper or copper alloy, are usually used in the formed substrate for providing electrical connections to and among various devices located on the surface of the substrate, examples of such devices being integrated circuits (semiconductor chips) and discrete passive devices, such as capacitors, resistors, inductors, and the like. The discrete passive devices occupy a high percentage of the surface area of the completed substrate, which is undesirable from a future design aspect because of the increased need and demand for miniaturization in today's substrates and products containing same art. In order to increase the available substrate surface area (also often referred to as “real estate”), there have been a variety of efforts to include multiple functions (e.g. resistors, capacitors and the like) on a single component for mounting on a board. When passive devices are in such a configuration, these are often referred to collectively and individually as integral passive devices or the like, meaning that the functions are integrated into the singular component. Because of such external positioning, these components still utilize, albeit less than if in singular form, board “real estate.” In response, there have also been efforts to embed discrete passive components within the board, such components often also referred to as embedded passive components. A capacitor or resistor designed for disposition within (e.g., between selected layers) a PCB (board) substrate may thus be referred to as an embedded integral passive component, or, more simply, an embedded resistor or capacitor. Such a capacitor thus provides internal capacitance while a resistor provides internal resistance. The result of this internal positioning is that it is unnecessary to also position such devices externally on the PCB's outer surface(s), thus saving valuable PCB surface area.
As defined in co-pending application Ser. No. 11/031,074 (relating to providing internal capacitors), for a fixed capacitor area, two known approaches are available for increasing the planar capacitance (capacitance/area) of an internal capacitor. In one such approach, higher dielectric constant materials can be used, while in a second, the thickness of the dielectric can be reduced. These constraints are reflected in the following formula, known in the art, for capacitance per area:C/A=(Dielectric Constant of Laminate×Dielectric Constant in Vacuum/Dielectric Thickness)where: C is the capacitance and A is the capacitor's area.
Some of the patents listed below, particularly U.S. Pat. No. 5,162,977, mention use of various materials for providing desired capacitance levels under this formula, and many mention or suggest problems associated with the methods and resulting materials used to do so.
As stated in Ser. No. 11/031,074, there have been past attempts to provide internal capacitance and other internal conductive structures, components or devices (one good example being internal semiconductor chips) within circuitized substrates (PCBs), some of these including the use of nano-powders. The following are some examples of such attempts, including those using nano-powders and those using alternative measures.
In U.S. Pat. No. 6,704,207, entitled “Device and Method for Interstitial Components in a Printed Circuit Board”, issued Mar. 9, 2004, there is described a printed circuit board (PCB) which includes a first layer having first and second surfaces, with an above-board device (e.g., an ASIC chip) mounted thereon. The PCB includes a second layer having third and fourth surfaces. One of the surfaces can include a recessed portion for securely holding an interstitial component. A “via”, electrically connecting the PCB layers, is also coupled to a lead of the interstitial component. The described interstitial components include components such as diodes, transistors, resistors, capacitors, thermocouples, and the like. In what appears to be the preferred embodiment, the interstitial component is a resistor having a similar size to a “0402” resistor (manufactured by Rohm Co.), which has a thickness of about 0.014 inches.
In U.S. Pat. No. 6,616,794, entitled “Integral Capacitance For Printed Circuit Board Using Dielectric Nanopowders” and issued Sep. 9, 2003, there is described a method for producing integral capacitance components for inclusion within printed circuit boards in which hydro-thermally prepared nano-powders permit the fabrication of dielectric layers that offer increased dielectric constants and are readily penetrated by micro-vias. In the method described in this patent, a slurry or suspension of a hydro-thermally prepared nano-powder and solvent is prepared. A suitable bonding material, such as a polymer, is mixed with the nano-powder slurry, to generate a composite mixture which is formed into a dielectric layer. The dielectric layer may be placed upon a conductive layer prior to curing, or conductive layers may be applied upon a cured dielectric layer, either by lamination or metallization processes, such as vapor deposition or sputtering.
In U.S. Pat. No. 6,544,651, entitled “High Dielectric Constant Nano-Structure Polymer-Ceramic Composite” and issued Apr. 3, 2003, there is described a polymer-ceramic composite having high dielectric constants formed using polymers containing a metal acetylacetonate (acacs) curing catalyst. In particular, a certain percentage of Co (III) may increase the dielectric constant of a certain epoxy. The high dielectric polymers are combined with fillers, preferably ceramic fillers, to form two phase composites having high dielectric constants. Composites having about 30 to about 90% volume ceramic loading and a high dielectric base polymer, preferably epoxy, were apparently found to have dielectric constants greater than about 60. Composites having dielectric constants greater than about 74 to about 150 are also mentioned in this patent. Also mentioned are embedded capacitors with capacitance densities of at least 25 nF/cm.sup.2, preferably at least 35 nF/cm.sup.2, most preferably 50 nF/cm.sup.2.
In U.S. Pat. No. 6,524,352, entitled “Method Of Making A Parallel Capacitor Laminate” and issued Feb. 25, 2003, there is defined a parallel capacitor structure capable of forming an internal part of a larger circuit board or the like structure to provide capacitance therefore. Alternatively, the capacitor may be used as an inter-connector to interconnect two different electronic components (e.g., chip carriers, circuit boards, and even semiconductor chips) while still providing desired levels of capacitance for one or more of said components. The capacitor includes at least one internal conductive layer, two additional conductor layers added on opposite sides of the internal conductor, and inorganic dielectric material (preferably an oxide layer on the second conductor layer's outer surfaces or a suitable dielectric material such as barium titanate applied to the second conductor layers). Further, the capacitor includes outer conductor layers atop the inorganic dielectric material, thus forming a parallel capacitor between the internal and added conductive layers and the outer conductors.
In U.S. Pat. No. 6,446,317, entitled “Hybrid Capacitor And Method Of Fabrication Therefore”, and issued Sep. 10, 2002, there is described a hybrid capacitor associated with an integrated circuit package that provides multiple levels of excess, off-chip capacitance to die loads. The hybrid capacitor includes a low inductance, parallel plate capacitor which is embedded within the package and electrically connected to a second source of off-chip capacitance. The parallel plate capacitor is disposed underneath a die, and includes a top conductive layer, a bottom conductive layer, and a thin dielectric layer that electrically isolates the top and bottom layers. The second source of off-chip capacitance is a set of self-aligned via capacitors, and/or one or more discrete capacitors, and/or an additional parallel plate capacitor. Each of the self-aligned via capacitors is embedded within the package, and has an inner conductor and an outer conductor. The inner conductor is electrically connected to either the top or bottom conductive layer, and the outer conductor is electrically connected to the other conductive layer. The discrete capacitors are electrically connected to contacts from the conductive layers to the surface of the package. During operation, one of the conductive layers of the low inductance parallel plate capacitor provides a ground plane, while the other conductive layer provides a power plane.
In U.S. Pat. No. 6,395,996, entitled “Multi-layered Substrate With Built-In Capacitor Design” and issued May 28, 2002, there is described a multi-layered substrate having built-in capacitors which are used to decouple high frequency noise generated by voltage fluctuations between a power plane and a ground plane of a multi-layered substrate. At least one kind of dielectric material, which has filled-in through holes between the power plane and the ground plane and includes a high dielectric constant, is used to form the built-in capacitors.
In U.S. Pat. No. 6,370,012, entitled “Capacitor Laminate For Use In A Printed Circuit Board And As An Inter-connector” and issued Apr. 9, 2002, there is described a parallel capacitor structure capable of forming an internal part of a larger circuit board or the like structure to provide capacitance therefore. Alternatively, the capacitor may be used as an inter-connector to interconnect two different electronic components (e.g., chip carriers, circuit boards, and even semiconductor chips) while still providing desired levels of capacitance for one or more of said components. The capacitor includes at least one internal conductive layer, two additional conductor layers added on opposite sides of the internal conductor, and inorganic dielectric material (preferably an oxide layer on the second conductor layer's outer surfaces or a suitable dielectric material such as barium titanate applied to the second conductor layers). Further, the capacitor includes outer conductor layers atop the inorganic dielectric material, thus forming a parallel capacitor between the internal and added conductive layers and the outer conductors.
In U.S. Pat. No. 6,242,282, entitled “Circuit Chip Package and Fabrication Method”, issued Jun. 5, 2001, there is described a method for packaging a chip which includes the steps of providing an interconnect layer including insulative material having a first side and a second side, initial metallization patterned on second side metallized portions of the second side and not on second side non-metallized portions of the second side, a substrate via extending from the first side to one of the second side metallized portions, and a chip via extending from the first side to the second side non-metallized portion. The method also includes positioning a chip on the second side with a chip pad of the chip being aligned with the chip via, and patterning connection metallization on selected portions of the first side of the interconnect layer and in the via so as to extend to the second side metallized portion and to the chip pad. About the chip is molded a “substrate” or other dielectric material.
In U.S. Pat. No. 6,207,595, entitled “Laminate and Method of Manufacture Thereof”, issued Mar. 27, 2001, there is described a fabric-resin dielectric material for use in a laminate structure and method of its manufacture. The resulting structure is adaptable for use in a printed circuit board or chip carrier substrate. The resin may be an epoxy resin such as is currently used on a large scale worldwide for “FR-4” composites. A resin material based on bismaleimide-triazine (BT) is also acceptable, this patent further adding that more preferably, the resin is a phenolically hardenable resin material as is known in the art, with a glass transition temperature of about 145 degrees Celsius (C.).
In U.S. Pat. No. 6,150,456, entitled “High Dielectric Constant Flexible Polyimide Film And Process Of Preparations, issued Nov. 21, 2000, there is described a flexible, high dielectric constant polyimide film composed of either a single layer of an adhesive thermoplastic polyimide film or a multilayer polyimide film having adhesive thermoplastic polyimide film layers bonded to one or both sides of the film and having dispersed in at least one of the polyimide layers from 4 to 85 weight % of a ferroelectric ceramic filler, such as barium titanate or polyimide-coated barium titanate, and having a dielectric constant of from 4 to 60. The high dielectric constant polyimide film can be used in electronic circuitry and electronic components such as multilayer printed circuits, flexible circuits, semiconductor packaging and buried (internal) film capacitors
In U.S. Pat. No. 6,084,306, entitled “Bridging Method of Interconnects for Integrated Circuit Packages”, issued Jul. 4, 2000, there is described an integrated circuit package having first and second layers, a plurality of routing pads being integral with the first layer, a plurality of upper and lower conduits, respectively, disposed on the upper and lower surfaces of the first layer, one of the upper conduits electrically connected to one of the lower conduits, a plurality of pads disposed on the second layer, vias that electrically connect the pads to the lower conduits and a chip adhered to the second layer having bonding pads, at least one of which is electrically connected to one of the routing pads.
In U.S. Pat. No. 6,068,782, entitled “Individual Embedded Capacitors For Laminated Printed Circuit Boards” and issued May 30, 2000, there is described a method of fabricating individual, embedded capacitors in multilayer printed circuit boards. The method is allegedly compatible of being performed using standard printed circuit board fabrication techniques. The capacitor fabrication is based on a sequential build-up technology employing a first pattern-able insulator. After patterning of the insulator, pattern grooves are filled with a high dielectric constant material, typically a polymer/ceramic composite. Capacitance values are defined by the pattern size, thickness and dielectric constant of the composite. Capacitor electrodes and other electrical circuitry can be created either by etching laminated copper, by metal evaporation or by depositing conductive ink.
In U.S. Pat. No. 5,831,833, entitled “Bare Chip Mounting Printed Circuit Board and a Method of Manufacturing Thereof by Photo-etching”, issued Nov. 3, 1998, there is described a method of manufacturing a “bare chip” multi-layer printed circuit board in which arbitrary numbers of wiring circuit conductor layers and insulating layers are alternately stacked on one or both surfaces of a printed circuit board as a substrate, and a recessed portion with an upper opening capable of mounting and resin-encapsulating a bare chip part is formed on the surface of the printed circuit board. In what appears to be the preferred embodiment, one of the insulating layers is made from a photosensitive resin, and the bare chip part mounting recessed portion is formed by photo-etching the insulating layer made from the photosensitive resin.
In U.S. Pat. No. 5,426,263, entitled “Electronic Assembly Having a Double-sided Leadless Component”, issued Jun. 20, 1995, there is described an electronic assembly which has a double-sided leadless component and two printed circuit boards. The component has a plurality of electrical terminations or pads on both opposing major surfaces. Each of the printed circuit boards has a printed circuit pattern that has a plurality of pads that correspond to the electrical terminations on both sides of the double-sided leadless component. The electrical terminals on one side of the component are attached to the pads on the first board and the electrical terminals on the other side of the leadless component are attached to the pads on the second board. The printed circuit boards are joined together to form a multilayered circuit board so that the double-sided leadless component is buried or recessed inside. The component is attached to the pads of the printed circuit board using solder.
In U.S. Pat. No. 5,280,192, entitled “Three-dimensional Memory Card Structure With Internal Direct Chip Attachment”, issued Jan. 18, 1994, there is described a card structure which includes an internal three dimensional array of implanted semiconductor chips. The card structure includes a power core and a plurality of chip cores. Each chip core is joined to the power core on opposite surfaces of the power core, and each chip core includes a compensator core having a two dimensional array of chip wells. Each chip well allows for a respective one of the semiconductor chips to be implanted therein. Further, a compliant dielectric material is disposed on the major surfaces of the compensator core except at the bottoms of the chip wells. The compliant dielectric material has a low dielectric constant and has a thermal coefficient of expansion compatible with those of the semiconductor chips and the compensator core, so that thermal expansion stability with the chips and the compensator core is maintained.
In U.S. Pat. No. 5,162,977, entitled “Printed Circuit Board Having An Integrated Decoupling Capacitive Element” and issued Nov. 10, 1992, there is described a PCB which includes a high capacitance power distribution core, the manufacture of which is compatible with standard printed circuit board assembly technology. The high capacitance core consists of a ground plane and a power plane separated by a planar element having a high dielectric constant. The high dielectric constant material is typically glass fiber impregnated with a bonding material, such as epoxy resin loaded with a ferroelectric ceramic substance having a high dielectric constant. The ferroelectric ceramic substance is typically a nano-powder combined with an epoxy bonding material. According to this patent, the resulting capacitance of the power distribution core is sufficient to totally eliminate the need for decoupling capacitors on a PCB. Use of pre-fired and ground ceramic nano-powders in the dielectric layer poses obstacles for the formation of thru-holes (conductive holes permitting electronic communication between conductive layers of a PCB), however. Pre-fired and ground ceramic nano-powder particles have a typical dimension in the range of 500-20,000 nanometers (nm). Furthermore, the particle distribution in this range is generally rather broad, meaning that there could be a 10,000 nm particle alongside a 500 nm particle. The distribution within the dielectric layer of particles of different size often presents major obstacles to thru-hole formation where the thru-holes are of extremely small diameter, also referred to in the industry as micro-vias due to the presence of the larger particles. Another problem associated with pre-fired ceramic nano-powders is the ability for the dielectric layer to withstand substantial voltage without breakdown occurring across the layer. Typically, capacitance layers within a PCB are expected to withstand at least 300 volts (V) in order to qualify as a reliable component for PCB construction. The presence of the comparatively larger ceramic particles in pre-fired ceramic nano-powders within a capacitance layer prevents extremely thin layers from being used because the boundaries of contiguous large particles provide a path for voltage breakdown. This is even further undesirable because, as indicated by the equation cited above, greater planar capacitance may also be achieved by reducing the thickness of the dielectric layer. The thickness is thus limited by the size of the particles therein.
In U.S. Pat. No. 5,099,309, entitled “Three-dimensional Memory Card Structure With Internal Direct Chip Attachment”, issued Mar. 24, 1992, there is described a memory card structure containing an embedded three dimensional array of semiconductor memory chips. The card structure includes at least one memory core and at least one power core which are joined together in an overlapping relationship. Each memory core comprises a copper-invar-copper (CIC) thermal conductor plane having a two dimensional array of chip well locations on each side of the plane. Polytetrafluoroethylene (PTFE) covers the major surfaces of the thermal conductor plane except at the bottoms of the chip wells. Memory chips are placed in the chip wells and are covered by insulating and wiring levels. Each power core comprises at least one CIC electrical conductor plane and PTFE covering the major surfaces of the electrical conductor plane. Provision is made for providing electrical connection pathways and cooling pathways along vertical as-well as horizontal planes internal to the card structure.
In U.S. Pat. No. 5,079,069, entitled “Capacitor Laminate For Use In Capacitive Printed Circuit Boards And Methods Of Manufacture” and issued Jan. 7, 1992, there is described a capacitor laminate which allegedly serves to provide a bypass capacitive function for devices mounted on the PCB, the capacitor laminate being formed of conventional conductive and dielectric layers whereby each individual external device is allegedly provided with capacitance by a proportional portion of the capacitor laminate and by borrowed capacitance from other portions of the capacitor laminate, the capacitive function of the capacitor laminate being dependent upon random firing or operation of the devices. That is, the resulting PCB still requires the utilization of external devices thereon, and thus does not afford the PCB external surface area real estate savings mentioned above which are desired and demanded in today's technology.
In U.S. Pat. No. 5,016,085, entitled “Hermetic package for integrated circuit chips, issued May 14, 1991, there is described a hermetic package which has an interior recess for holding a semiconductor chip. The recess is square and set at 45 degrees with respect to the rectangular exterior of the package. The package uses ceramic layers which make up the package's conductive planes with the interior opening stepped to provide connection points. The lowest layer having a chip opening therein may be left out of the assembly to provide a shallower chip opening recess. This of course is not the same as an internally formed capacitance or semiconductor component of the nature described above, but it does mention internal ceramic layers for a specified purpose as part of an internal structure.
The teachings of the above patents and cited co-pending applications are incorporated herein by reference, as are the teachings of the patents listed below.
Generally speaking, with respect to commercially available dielectric powders which have been used in internal conductive structures such as mentioned in some of the above patents, among these being metal titanate-based powders (see, e.g., U.S. Pat. No. 6,150,456, cited above), such powders are known to be produced by a high-temperature, solid-state reaction of a mixture of the appropriate stoichiometric amounts of oxides or oxide precursors (e.g., carbonates, hydroxides or nitrates) of barium, calcium, titanium, and the like. In such calcination processes, the reactants are wet-milled to accomplish a desired final mixture. The resulting slurry is dried and fired at elevated temperatures, sometimes as high as 1,300 degrees Celsius (C.), to attain the desired solid state reactions. Thereafter, the fired product is milled to produce a powder. Although the pre-fired and ground dielectric formulations produced by solid phase reactions are acceptable for many electrical applications, these suffer from several disadvantages. First, the milling step serves as a source of contaminants, which can adversely affect electrical properties. Second, the milled product consists of irregularly shaped fractured aggregates which are often too large in size and possess a wide particle size distribution, 500-20,000 nm. Consequently, films produced using these powders are limited to thicknesses greater than the size of the largest particle. Thirdly, powder suspensions or composites produced using pre-fired ground ceramic powders must be used immediately after dispersion, due to the high sedimentation rates associated with large particles. The stable crystalline phase of barium titanate for particles greater than 200 nm is tetragonal and, at elevated temperatures, a large increase in dielectric constant occurs due to a phase transition. It is thus clear that methods of making PCBs which rely on the advantageous features of using nano-powders as part of the PCB's internal components or the like, such as those described in selected ones of the above patents, possess various undesirable aspects which are detrimental to providing a PCB with optimal functioning capabilities when it comes to internal capacitance or other electrical operation. This is particularly true when the desired final product attempts to meet today's miniaturization demands, including the utilization of high density patterns of thru-holes therein.
The present invention, as indicated above, is directed to providing internal resistors for a circuitized substrate, and, more particularly, to the use of a material for the resistor which includes dielectric components in addition to a metal additive. Use of such additives is an important aspect of the invention to assure desired dielectric constants for the material. Use of metal additives in the manner taught herein is also considered unobvious because of the well known property of metals to conduct electricity. As defined herein, however, the additives are sufficiently insulated to prevent adequate contact between particles thereof, thus preventing undesirable electrical current passage while still enabling composition adjustment so as to provide resistances of differing values, depending on the operational requirements needed for the formed circuit(s) of the substrate. A need exists for providing embedded resistors within circuitized substrates such as PCBs which can be accomplished in a facile, relatively inexpensive manner and which assures a final product capable of providing desired circuit resistances. Such a need is particularly significant with respect to PCBs having high density internal thru-holes as defined below. It is believed that such structures (products, such as electrical assemblies, PCBs, etc.) adapted for using such materials, would constitute significant advancements in the art.
The following patents discuss in particular various resistors and how same are used, one of these discussing use within electronic packages including circuitized substrates such as discussed herein.
In U.S. Pat. No. 6,740,701, entitled “Resistive Film” and issued May 25, 2004, there is described a resistive film for use in a potentiometer. The film is in contact with a movable wiper. The film includes a cured polymer resin and a cured thermosetting resin. Conductive particles of carbon black and graphite are dispersed in the film. The conductive particles cause the resins to be electrically resistive. Carbon nano-particles are also dispersed in the film. The nano-particles increase the wear resistance of the resistive film and reduce electrical noise as the wiper moves across the film. In the preparation of an exemplary composition, a polymer solution is made by mixing 10-20 wt. percent of a polymer and 0-10 wt. percent thermosetting resin in 60-80 wt. percent N-methyl pyrrolidone, based upon the total composition. The polymer is mixed with both the conductive and nano-particles to form a paste with a fine particle size. At this point, surfactants and rheological additives may be added if desired to modify the properties of the resistive composition. The particle size range and viscosity of the paste is monitored to get a resistive paste suitable for application in position sensors. The milling time and milling quantity on the ball mill determines the final particle distribution, size and resulting rheology.
In U.S. Pat. No. 6,500,350, entitled “Formation of Thin Film Resistors” and issued Dec. 31, 2002, there is described a method for forming a patterned layer of resistive material in electrical contact with a layer of electrically conducting material. A three-layer structure is formed which comprises a metal conductive layer, an intermediate layer formed of material which is degradable by a chemical etchant, and a layer of resistive material of sufficient porosity such that the chemical etchant for the intermediate layer may seep through the resistive material and chemically degrade the intermediate layer so that the resistive material may be ablated from the conductive layer wherever the intermediate layer is chemically degraded. A patterned photo-resist layer is formed on the resistive material layer. The resistive material layer is exposed to the chemical etchant for the intermediate layer so that the etchant seeps through the porous resistive material layer and degrades the intermediate layer. Then, portions of the resistive material layer are ablated away wherever the intermediate layer has been degraded.
In U.S. Pat. No. 6,396,387, entitled “Resistors For Electronic Packaging” and issued May 28, 2002, there are described thin layer resistors which are formed on an insulating substrate, which resistors may be embedded within a printed circuit board. Preferred resistive materials are homogeneous mixtures of metals, such as platinum, and dielectric materials, such as silica or alumina. Even minor amounts of dielectric material admixed with a metal significantly increase the resistance of the metal. Preferably, the resistive material is deposited on the insulating substrate by combustion chemical vapor deposition (CCVD). In the case of zero valence metals and dielectric material, the homogeneous mixture is achieved by co-deposition of the metal and dielectric material by CCVD. To form discrete patches of the resistive material, substantially any metal-based resistor material, including those based on the noble metals, can be etched away. Thus, a layer of resistive material may be covered with a patterned resist, e.g., an exposed and developed photo-resist, and exposed portions of the underlying layer of resistive material etched away. This patent also describes the formation of thin layer resistors including the insulating substrate, discrete patches of a layer of resistive material, and conductive material in electrical contact with spaced-apart locations on the patches of resistive material layer, such conductive material providing for electrical connection of the resistive material patches with electronic circuitry. Such structures of insulating material, resistive material, and conductive material may be formed by selective etching procedures.
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1. Field of the Invention
The invention disclosed herein relates to novel zeolite catalyst compositions useful for the selective production of 1,4-dialkylbenzene compounds.
2. Description of the Prior Art
The disproportionation of aromatic hydrocarbons in the presence of zeolite catalysts has been described by Grandio et al. in the OIL AND GAS JOURNAL, Vol. 69, Number 48 (1971).
U.S. Pat. Nos. 3,126,422; 3,413,374; 3,598,878; 3,598,879 and 3,607,961 show vapor-phase disproportionation of toluene over various catalysts.
In these prior art processes, the dimethylbenzene product produced has the equilibrium composition of approximately 24 percent of 1,4-, 54 percent of 1,3- and 22 percent of 1,2-isomer. Of the dimethylbenzene isomers, 1,3-dimethylbenzene is normally the least desired product, with 1,2- and 1,4-dimethylbenzene being the more useful products. 1,4-dimethylbenzene is of particular value, being useful in the manufacture of terephthalic acid which is an intermediate in the manufacture of synthetic fibers such as "Dacron." Mixtures of dimethylbenzene isomers, either alone or in further admixture with ethylbenzene, have previously been separated by expensive superfractionation and multistage refrigeration steps. Such process, as will be realized, involves high operation costs and has a limited yield.
Various modified zeolite catalysts have been developed to alkylate or disproportionate toluene with a greater or lesser degree of selectivity to 1,4-dimethylbenzene isomer. Hence, U.S. Pat. Nos. 3,972,832, 4,034,053, 4,128,592 and 4,137,195 disclose particular zeolite catalysts which have been treated with compounds of phosphorus and/or magnesium. Boron-containing zeolites are shown in U.S. Pat. No. 4,067,920 and antimony-containing zeolites in U.S. Pat. No. 3,979,472. Similarly, U.S. Pat. Nos. 3,965,208 and 4,117,026 disclose other modified zeolites useful for shape selective reactions.
While the above-noted prior art is considered of interest in connection with the subject matter of the present invention, the conversion process described herein, utilizing a crystalline zeolite catalyst of specified characteristics which has undergone the particular treatment disclosed, has not, insofar as is known, been previously described.
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The electrophoretic display (EPD or EPID) is a non-emissive device based on the electrophoresis phenomenon of charged pigment particles suspended in a solvent. It was first proposed in 1969. The display typically comprises two plates with electrodes placed opposing each other, separated by spacers. One of the electrodes is usually transparent. A suspension composed of a colored solvent and charged pigment particles, is enclosed between the two plates. When a voltage difference is imposed between the two electrodes, the pigment particles migrate to one side and then either the color of the pigment or the color of the solvent can be seen according to the polarity of the voltage difference.
There are several different types of EPDs. In the partition type EPD (see M. A. Hopper and V. Novotny, IEEE Trans. Electr. Dev., 26(81):1148-1152 (1979)), there are partitions between the two electrodes for dividing the space into smaller cells in order to prevent undesired movements of particles, such as sedimentation. The microcapsule type EPD (as described in U.S. Pat. Nos. 5,961,804 and 5,930,026) has a substantially two dimensional arrangement of microcapsules each having therein an electrophoretic composition of a dielectric fluid and a suspension of charged pigment particles that visually contrast with the dielectric solvent. Another type of EPD (see U.S. Pat. No. 3,612,758) has electrophoretic cells that are formed from parallel line reservoirs. The channel-like electrophoretic cells are covered with, and in electrical contact with, transparent conductors. A layer of transparent glass from which side the panel is viewed overlies the transparent conductors.
An improved EPD technology was disclosed in co-pending applications, U.S. Ser. No. 09/518,488, filed on Mar. 3, 2000 (corresponding to WO 01/67170), U.S. Ser. No. 09/759,212, filed on Jan. 11, 2001 (corresponding to WO 02/56097), U.S. Ser. No. 09/606,654, filed on Jun. 28, 2000 (corresponding to WO 02/01281) and U.S. Ser. No. 09/784,972, filed on Feb. 15, 2001 (corresponding to WO 02/65215), all of which are incorporated herein by reference. The improved EPD comprises closed cells formed from microcups of well-defined shape, size and aspect ratio, filled with charged pigment particles dispersed in a dielectric solvent, and sealed with a polymeric sealing layer.
All of these EPDs may be driven by a passive matrix system. For a typical passive matrix system, there are row electrodes on the top side and column electrodes on the bottom side of the cells. The top row electrodes and the bottom column electrodes are perpendicular to each other. However, there are two well-known problems which are associated with EPDs driven by a passive matrix system: cross-talk and cross-bias. Cross-talk occurs when the particles of a cell (pixel) are biased by the electric field of a neighboring cell (pixel). FIG. 1 provides an example. The bias voltage of the cell A drives the positively charged particles towards the bottom of the cell. Since cell B has no voltage bias, the positively charged particles in cell B are expected to remain at the top of the cell. However, if the two cells, A and B, are close to each other, the top electrode voltage of cell B (30V) and the bottom electrode voltage of cell A (0V) create a cross talk electric field which forces some of the particles in cell B to move downwards. Widening the distance between adjacent cells may reduce such a crosstalk effect but the resolution of the display will also be reduced.
The cross talk problem may be lessened if a cell has a significantly high threshold voltage. The threshold voltage, in the context of the present invention, is defined to be the minimum (or onset) bias voltage required to move particles away from their current position. If the cells have a sufficiently high threshold voltage, the cross-talk may be reduced or eliminated without sacrificing the resolution of the display. A high threshold voltage may be achieved by, for example, increasing the particle-particle interaction or the particle electrode interaction in the electrophoretic cells. Unfortunately, most approaches to increase the threshold voltage tend to result in a significant increase in display driving voltage or a decrease in switching rate.
In addition to the crosstalk by neighboring cells, cross bias is also possible in a passive matrix display. The voltage applied to a column electrode not only provides the driving bias for the cell on the scanning row, but it also affects the bias across the non-scanning cells on the same column. This undesired bias may force the particles of a non-scanning cell to migrate to the opposite electrode. This results in changes in image density and a significant deterioration of the display contrast. A system having gating electrodes was disclosed in U.S. Pat. Nos. 4,655,897 and 5,177,476 (assigned to Copytele, Inc.) to provide EPDs capable of high resolution at relative high driving voltage using a two layer electrode structure, one of which layers serves as a gating electrode. Although these references teach how the threshold voltage may be raised by the use of gating electrodes, the cost for fabricating the two electrode layers is extremely high due to the complexity of the structure and the low yield rate. In addition, in this type of EPDs, the electrodes are exposed to the solvent, which could result in an undesired electroplating effect and deterioration in the display operation longevity.
The in-plane switched EPD device disclosed in U.S. Pat. No. 6,239,896 uses a magnetic bottom substrate to attract the magnetic particles and provide a threshold effect against the undesirable particle movement. The row and column electrodes are implemented on the bottom layers forming the driving dot matrix. The in-plane electrodes are significantly more difficult to manufacture than the normal up-down electrodes, particularly for high resolution displays. The switching rate of the in-plane displays are slower at a comparable operation voltage since the distance between electrodes in the in-plane switching mode is typically larger than the normal up-down mode. Moreover, the color saturation of a color display will be poor due to the lack of either true white or true black state.
Therefore, there is still a need for an electrophoretic display in which the cross talk and cross bias effects will not cause a degradation of display performance, even if cells having a relatively low intrinsic threshold voltage are used.
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The following relates to an optical system and its method of operation.
Today, a number of machines, such as medical analyzers and the like, operate or otherwise perform their functions by looking at or reading a signal. In some cases, this signal may be a light signal generated by a particular marker or label attached to an item of interest. In order to read this light signal, these machines may use an optical system which gathers the light signal and guides the gathered light signal to a reader, such as an element that produces an electrical signal in response to the gathered and guided light signal.
For such machines to operate as intended, it is desirable to check or to calibrate the optical system from time to time. Depending on the type of machine involved, this checking may be rather difficult. Also, the method or device used to check the optical system may not always accurately check the optical system. Accordingly, it is desirable to provide an improved optical system.
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WO 02/069791 describes a device for measuring blood glucose in living tissue. It comprises an electrode arrangement with a ground electrode and a signal electrode. A signal source applies an electrical AC-signal of known voltage or current through a resistor to the electrodes, and a detector determines the voltage over the electrodes. This depends on the dielectric properties of the tissue, which, as it has been found, are indicative of the glucose level within the tissue.
Devices of this type have been found to deliver good results, but they require a substantial effort for calibration and are prone to drift, in particular when the environmental conditions change or when they are being displaced. Differential methods have been used to improve measurement accuracy in other fields of technology. Differential methods are generally based on two or more measurements, wherein one or more measurement conditions are changed between measurements. Depending on the specific application, the influence of some parameters can be eliminated or reduced by calculating the difference between the measurements.
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Program-controlled units such as microprocessors, microcontrollers, signal processors, etc., have been known in numerous forms for many years.
A known problem of program-controlled units is that, in many cases, faults (operating errors or “bugs”) that occur during execution of a software program cannot be readily localized and/or remedied.
One previously used (and in some cases still used) approach for localizing and remedying faults occurring in a program-controlled unit is to produce a special “bond-out” version of the program-controlled units that are used for program development. Bond-out versions of program-controlled units are specially-produced in small batches, and differ from the standard mass-produced versions of the respective program-controlled units in that they include more input and/or output terminals, and the additional input and/or output terminals are connected to locations on the program-controlled unit that are not freely accessible in the standard version of the program-controlled unit. Typically, these additional input/output terminals are connected to the processor core of the bond-out version. As a result, information on internal states or processes of the program-controlled unit (e.g., addresses, data and/or control signals generated in the processor core, such as the respective current state of the program counter) that are typically not accessible in the standard version, can be output from the bond-out program-controlled unit, and evaluated outside the program-controlled unit. By evaluating the information it is possible to trace the profile of the processes occurring within the program-controlled unit, as a result of which faults occurring in the program-controlled unit can be localized and corrected.
However, the use of bond-out versions is associated with a series of disadvantages. In particular, the bond-out versions of program-controlled units are larger and more expensive than the standard production versions and, what is more important, the bond-out versions generally do not behave in precisely the same way as the standard versions. Therefore, problems that occur in bond-out versions may not arise in corresponding standard production versions, and problems may arise in the standard production versions that do not arise in corresponding bond-out versions.
For this reason, in some cases, another approach has been adopted in which standard production version program-controlled units are equipped with on-chip debug resources that facilitate the extraction of information from the program-controlled unit core for debugging purposes. These on-chip resources also facilitate outputting (“off-loading”) the extracted information from the program-controlled unit, or storing the extracted information in special memory arrays provided on the program-controlled unit. The outputting and/or storing operations are performed using an interface that includes only a small number of pins, which in some cases are also be used for other purposes.
FIG. 2 is a simplified block diagram showing a conventional program-controlled unit (microprocessor) 200. Program-controlled unit 200 is a microcontroller and comprises a core C, peripheral units P1, P2, P3 which are connected to the core C via a first bus BUS1, storage devices S1, S2, S3 which are connected to the core C via a second bus BUS2, debug resources DR which are connected to the core C, and an interface SS which is assigned to the debug resources DR, and via which the debug resources DR output data that is to be output to an external device and via which the debug resources DR are controlled by the external device (not shown).
The peripheral units P1 to P3 are, for example, an A/D converter, a timer, a coder, a compression device, a Controller Area Network (CAN) interface, or other units that can be integrated into microcontrollers, and the storage devices are, for example, a RAM, a ROM and a flash memory.
The debug resources DR are preferably capable of outputting what is referred to as trace information. For this purpose, the debug resources DR monitor for conditions that can be predefined from outside the program-controlled unit occurring within the core of the program-controlled unit, and whenever the condition or one of the conditions is fulfilled, addresses, data and/or control signals, which can be predefined from outside the program-controlled unit, are output from the program-controlled unit without interrupting the operation of the program-controlled unit. As a result it is possible, for example, but by far not exclusively possible, for the debug resources DR to output the data that is then fed to the core from the program-controlled unit whenever the core wishes to read data from a specific address or a specific address area.
In general, the debug resources DR also carry out further actions which are necessary or helpful for localizing and remedying faults which occur in the program-controlled unit. As a result, the debug resources DR are, for example, capable of stopping the program-controlled unit when specific conditions occur, for example when a specific program counter reading is reached, and reading out or changing the contents of registers of interest.
Such debug resources, also referred to as On-Chip Debug Support (OCDS) modules, are known, so further details will not be described.
Owing to the increasing significance of the presence of debug resources in program-controlled units, a standard which is referred to as “The Nexus 5001 Forum Standard for a Global Embedded Processor Debug Interface” was defined for the corresponding interface (e.g., interface SS) in 1999 by the IEEE Industry Standards and Technology Organization (IEEE-ISTO), by means of which interface the debug resources can exchange data particularly efficiently with a analyzing device (e.g., a workstation) that is provided outside the program-controlled unit, for example with a debug control unit or emulation control unit, or with a measuring device such as, for example, a logic analyzer.
The debug resources and the NEXUS interface make it possible to detect and remedy faults occurring in program-controlled units with a relatively small amount of expenditure.
Nevertheless, the design and the operation of the debug resources DR can be very costly and complicated, especially in the case of relatively complex program-controlled units, for example in the case of program-controlled units with multiple cores. It is problematic here in particular to acquire and output the trace information: it may be necessary for a very large quantity of trace information to have to be output from the program-controlled unit in order to be able to localize and remedy faults occurring in the program-controlled unit, and furthermore it may also prove very complicated or even impossible to define the conditions whose occurrence determines the outputting of trace information.
What is needed is a program-controlled unit that facilitates efficient trace (e.g., debugging) operations while minimizing the amount of chip area required for on-chip debugging resources.
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Classical Catadioptric Telescopes employing concave spherical mirror objectives can be fast and aberration free in the visible spectrum, but suffer from field curvature and restrictions due to poor accessibility of their focal surfaces. In addition, correctors for such telescopes are either aspherical (See Schmidt, "A Rapid Coma-free Mirror System", reprinted in Amateur Telescope Making, Book Three, pp. 373-375, incorporated herein by reference.), or require tight centering and radius control along with aspherical "retouch" for best performance. (See Maksutov, "New Catadoiptric Meniscus Systems", Journal of Optical Society of America, Vol. 34, No. 5. May, 1944, pp. 270-284, incorporated herein by reference).
Spherical concave objective mirrors and spherical corrector lenses are desired for Catadioptric Telescopes because the mirrors can be economically produced in large sizes and spheres are easy to produce in unlimited quantities by well-controlled production processes and are easy to test. Therefore, spherical optics have tremendous advantage over aspheric optics such as parabolic telescope mirrors and aspheric corrector elements which always require scarce skills for their fabrication, and production of aspherics is frequently unpredictable or limited. In addition, except for field curvature, Catadioptric Telescopes employing spherical mirror objectives can be designed to provide larger fields of view than telescopes having aspheric objectives because the spherical surface has no unique optical center, and at the same time still can have good correction of aberrations. Consequently, the image of an object situated off the axis of the telescope and which would be aberrated by an aspheric primary may not be so aberrated by spherical optics.
The main problem of spherical mirrors in Catadioptric Telescopes is (negative) spherical aberration all across the field which must be corrected (nulled). Also the mirror's coma, astigmatism, and negative field curvature should be corrected for wide field use, and the introduction of false color should be avoided.
Obviously, small sub-aperture sized corrector elements, which can be located in the convergent beam should be much easier to produce than those required for telescopes employing a full aperture sized corrector. Most classical Catadioptric Telescopes require full sized corrector elements (located upstream of the objective) and still the field is not flat; because the mirror has a strongly curved (negative) focal surface and the corrector must (in order to yield positive spherical aberration) be either negative or too weak to null this curvature. Another class of Catadioptric Telescopes uses a sub-aperture sized negative achromat made of crown and flint glass or a Barlow lens having positive spherical aberration to correct to negative spherical aberration of spherical primary mirrors. This type of corrector is small and located within the convergent beam, but these telescopes are f/8 or slower and have non-negligible secondary color and tend to have only small useful fields. In addition, the negative optical power of negative achromats obviously can not correct the negative field curvature due to a concave spherical primary mirror objective and always exacerbates it.
Still another class of Catadioptric Telescopes uses a negative power, or weak, one-glass sub-aperture sized corrector and requires more than two corrector elements for best performance, and/or requires (additional) corrective element(s) downstream of an intermediate image, real or virtual, to obtain aberration correction. (See R.D. Sigler, "All-spherical Catadioptric Telescope with Small Corrector Lenses", Applied Optics, Vol. 21, No. 15, 1 Aug. 1982, pp. 2804-2808, incorporated herein by reference.) But again, these correctors all have net negative optical power or are too weak to correct the negative field curvature due to the spherical primary mirror. Also, these designs tend to be slow (i.e. f/7-f/15.7) and to have detrimentally small fields of less than one degree, or one-half degree due particularly to color and astigmatism.
These classes of classical and other Catadioptric Telescopes also require tight centering tolerances for the corrector surfaces and also for the telescope assembly. In addition, due to requirements on spacing between elements of the classes of telescopes that use sub-aperture sized corrector elements, all these have lenses awkwardly positioned along the optical axis as obstructions within the main tube of the telescope. It would be a great convenience, and remove obstructions to the optical path, for these corrector elements to be removed to the side as with a Newtonian style focus; and also sensitivity to positioning and centering errors should be substantially reduced.
Difficulties due to a curved focal surface can be accommodated by using curved photographic plates or curved films to fit the focal surface in the case of photography; or by the use of "field flatteners". Obviously, the use of curved photographic films, plates or curved photosensitive devices (photodetectors) imposes major restrictions in convenience an efficacy of use and fabrication which are avoided when a lensless standard camera or other device having a flat film plane or plano photographic plates, cut or roll film, flat photodiode array, or other such flat detector can be used directly in conjunction with a flat field telescope.
Field flatteners are extra lenses placed in contact or nearly in contact with the photographic film or surface and thus are a hindrance for visual use, and as they are quite near the image plane, dust and dirt can become quite noticeable. Alternatively, field curvature can be avoided by using a particular Cassegrain configuration in which the radius of curvature of the secondary mirror is chosen to be the same as the radius of the primary and reflects converging light back toward the primary and usually through a hole in it. This choice of equal radii for both mirrors tends to restrict the design; but much worse is the fact that all Cassegrain configurations are extremely sensitive to tilt and decenter of the secondary mirror. Cassegrains are neither simple nor easy to construct because the secondary has power (it is curved in order to extend the focus to provide accessibility to it). The Newtonian style plano secondary mirror is preferred in this regard in that it merely reflects light from the primary toward the side of the instrument for easy accessibility of the focal surface and does not amplify the focal length of the primary mirror and in in principle aberration free. Thus the Newtonian Secondary is relatively tolerant of tilt and decentering errors and also does not increase telescope focal length nor reduce its optical speed.
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In downhole operations, such as in bores for reservoirs (e.g. oil and gas reservoirs), downhole tools are often required to be rotated, such as for drilling the bore.
In some operations rotation is temporarily or selectively transmitted downhole. For example, in directional or controlled trajectory drilling, a steering portion of the downhole tool may be rotated only when the direction of drilling is changed; whilst the drill bit may be rotated more of the time.
In directional drilling, the vertical inclination and azimuth of a drilled bore may be controlled such that the bore may extend from the surface to a target area which is not vertically aligned with the point on the surface where drilling commences. This permits a wide area to be accessed from a single drilling location and is therefore particularly useful in offshore drilling operations.
Applicant's GB 2,343,470 and U.S. patent application Ser. No. 09/435,453, and also WO97\47848 and U.S. patent application Ser. No. 09/202,342 and U.S. patent application Ser. No. 10/470,031, the disclosures of which are incorporated herein by reference, describe arrangements including non-rotating offset masses to provide a desired offset of the drill string in the bore.
In some downhole operations there can be changes in the transmission of rotational drive that result in a driven component being inadvertently coupled or decoupled; or coupled or decoupled under undesirable conditions. For example, where a drive coupling is controlled by a fluid pressure or a fluid pressure differential, the driven component may be inadvertently coupled by an unplanned change in fluid pressure (e.g. if a pump fails). Undesirably transmitting drive to components can potentially damage the driven components or other parts of the downhole tool or associated equipment; or cause delay or impede operations.
It is among the objectives of at least one embodiment of at least one aspect of the present invention to seek to obviate or at least mitigate one or more problems and/or disadvantages of the prior art.
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{
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The present invention relates to a pixel unit, and more particularly to a pixel unit included in a multi-domain vertically aligned liquid crystal display.
The current trend is towards liquid crystal displays for achieving a larger panel size and a higher resolution. However, the characteristics of response time and wide-viewing angles of a liquid crystal display are still needed to be improved.
In order to improve the response time and the wide-viewing angles, a multi-domain vertically aligned (MVA) liquid crystal display is developed as shown in FIGS. 1(a) and (b). Liquid crystal molecules 13 around protrusions 12 which are formed on an upper substrate 10 and a lower substrate 11 are aligned with an advance inclination as shown in FIG. 1(a) by the protrusions 12. Therefore, when the liquid crystal molecules 13 are applied with an electric field, the liquid crystal molecules 13 are in the inclination state, so that the response time and the wide-viewing angle are improved.
Please refer to FIGS. 2(a) and (b) showing another type of a multidomain vertically aligned liquid crystal display. The protrusion 22 is only formed on the upper substrate 20, and the lower substrate 21 has corresponding slits 23 thereon. Therefore, the liquid crystal molecules 24 are aligned as those in FIG. 1, and the response time and the wide-viewing angle of the multi-domain vertically aligned liquid crystal display are improved.
The fabricating processes of the foresaid multi-domain vertically aligned liquid crystal display are complex, so that a cruciform bump structure 31 formed around a pixel electrode 30 as shown in FIG. 3 is developed. The fabricating process is easier, and the four regions having different alignments of the liquid crystal molecules are formed. However, disclination lines are generated at some positions around the pixel electrode, and the transmittance of the panel of the liquid crystal display are decreased.
The present invention provides a pixel unit for being used in a multi-domain vertically aligned liquid crystal display to overcome the foresaid drawbacks.
It is an object of the present invention to provide a pixel unit included in a multi-domain vertically aligned liquid crystal display.
In accordance with present invention, the pixel unit includes a first insulating substrate, a second insulating substrate, a plurality of liquid crystal molecules, an electric field generation device, and a cone protrusion.
The first insulating substrate has a first side and a second side.
The second insulating substrate has a third side and a fourth side.
A plurality of liquid crystal molecules are filled between the first side of the first insulating substrate and the fourth side of the second insulating substrate.
The electric field generation device provides an electric field to change alignment of the liquid crystal molecules.
The cone protrusion is formed on the first side of the first insulating substrate for generating an advance inclination of the liquid crystal molecules around the cone protrusion.
Preferably, the first substrate and the second substrate are substrates pervious to light.
Preferably, the substrates are glass substrates.
In addition, the electric field generation device includes a pixel electrode formed on the fourth side of the second insulating substrate, and a common electrode formed on the first side of the first insulating substrate.
Preferably, the cone protrusion is disposed above a center of the pixel electrode.
It is another object of the present invention to provide a method for fabricating a cone protrusion in a fabricating process of a liquid crystal display.
In accordance with the present invention, the method includes steps of providing an insulating substrate, forming a positive photoresist layer on the insulating substrate, performing an exposure on the positive photoresist layer by using a mask, wherein a masking region of the mask is a pattern having a masking rate decreased progressively from center to surrounding, and performing a development to remove the positive photoresist layer and form a cone protrusion on the insulating substrate.
Preferably, the insulating substrate is a substrate pervious to light.
Preferably, the substrate is a glass substrate.
Preferably, the masking region is circle-shaped.
Preferably, the liquid crystal display is a multi-domain vertically aligned liquid crystal display.
It is another object of the present invention to provide a method for fabricating a cone protrusion in a fabricating process of a liquid crystal display.
In accordance with the present invention, the method includes steps of providing an insulating substrate, forming a negative photoresist layer on the insulating substrate, performing an exposure on the negative photoresist layer by using a mask, wherein a masking region of the mask is a pattern having a masking rate decreased progressively from center to surrounding, and performing a development to remove the negative photoresist layer and form a cone protrusion on the insulating substrate.
Preferably, the insulating substrate is a substrate pervious to light.
Preferably, the substrate is a glass substrate.
Preferably, the masking region is circle-shaped.
Preferably, the liquid crystal display is a multi-domain vertically aligned liquid crystal display.
The present invention may best be understood through the following descriptions with reference to the accompanying drawings, in which:
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1. Field of the Invention
The present invention relates to a process for producing a semiconductor device such as a photovoltaic element including a solar cell, a photosensor, or the like.
2. Related Background Art
For the production of a solar cell which is categorized to a photovoltaic element, there are known various production processes. For instance, in the case of producing a solar cell having a photoelectric conversion semiconductor layer composed of a non-single crystalline semiconductor material (this solar cell will be hereinafter referred to as xe2x80x9cnon-single crystalline series solar cellxe2x80x9d), a plasma CVD (chemical vapor deposition) process has been widely adopted on an industrial scale. The non-single crystalline semiconductor material herein is meant to include an amorphous semiconductor material, a microcrystalline semiconductor material, a polycrystalline semiconductor material, and the like.
For the non-single crystalline series solar cell to be used as a sunlight power generation source, it is basically required that the photoelectric conversion semiconductor layer has a large area, the solar cell has excellent and stable solar cell characteristics and it exhibits a high photoelectric conversion efficiency, and the solar cell can be mass-produced In order to produce such non-single crystalline series solar cell by means of a plasma CVD process so as to satisfy these requirements, it is necessary to have due consideration so that as the photoelectric conversion semiconductor layer, a large area homogeneous semiconductor film having a uniform thickness and which excels in electrical, optical and photoconductive characteristics, mechanical characteristics, fatigue resistance upon repeated use, and use environmental characteristics can be repeatedly formed at a high speed and with a good reproducibility.
Separately, there have been proposed a variety of sunlight power generation systems using solar cells having such configuration as above described. Such sunlight power generation system typically comprises a unit in which a plurality of solar cell modules [comprising a plurality of solar cells (photovoltaic elements) electrically serialized while being sealed by a sealing material] are electrically connected with each other in series connection or parallel connection so as to obtain a desired electric current and a desired voltage. In this case, it is important that neither disconnection nor short are not occurred in each solar cell module and that all the solar cell modules are uniform as much as possible with respect to their output voltage and output electric current For this purpose, at a stage of forming the respective solar cell modules, it is an important factor that the semiconductor layers used therein, which are an utmost decisive factor of dominating the characteristics of the solar cell module, are made to be uniform in terms of the characteristics. Besides, in viewpoints of making it easy to design a solar cell module and simplifying the fabrication process of a solar cell module, it is important to make it possible to efficiently form a homogeneous semiconductor film having a uniform property over a large area, where this situation leads to improving the productivity of a solar cell and diminishing the production cost thereof.
Incidentally, the semiconductor layer of a solar cell (a non-single crystalline series solar cell) has a semiconductor junction such as p-i-n (or n-i-p) junction, p-n (or n-p) junction or the like. For instance, in the case where the semiconductor layer comprises an amorphous silicon (a-Si) material and has a p-i-n junction structure, the p-i-n junction structure comprises, for example, an n-type a-Si semiconductor layer, an i-type a-Si semiconductor layer and an p-type a-Si semiconductor layer stacked in this order, where the n-type a-Si semiconductor layer may be formed by subjecting a gaseous mixture of a film-forming raw material gas such as silane (SiH4 or the like) and an n-type dopant-supplying compound such as PH3 to glow discharge decomposition, the i-type a-Si semiconductor layer may be formed by subjecting said film-forming raw material gas to glow discharge decomposition, and the p-type a-Si semiconductor layer may be formed by subjecting a gaseous mixture of said film-forming raw material gas and an p-type dopant-supplying compound such as B2H6 to glow discharge decomposition.
For the production of a non-single crystalline series solar cell having such semiconductor junction, there are known methods using a multi-chambered plasma CVD apparatus comprising a plurality of film-forming chambers communicated with each other, where a semiconductor layer having a desired conduction type is formed by each film-forming chamber to form a semiconductor layer having a stacked structure with a desired semiconductor junction. As a representative example of such plasma CVD apparatus, there can be mentioned a roll-to-roll type plasma CVD apparatus for continuously forming a deposited film on an elongated substrate as disclosed, for instance, in U.S. Pat. No. 4,400,409. The roll-to-roll type plasma CVD apparatus described in this document comprises a plurality of glow discharge regions (film-forming spaces in other words) provided in a plurality of processing chambers communicated with each other. In said document, there is described that semiconductor elements having a semiconductor junction can be continuously formed by continuously transporting an elongated flexible substrate having a desired width in the longitudinal direction along a route of sequentially passing through the glow discharge regions while forming a semiconductor layer of a desired conduction type on said substrate by each glow discharge region.
In this apparatus, each glow discharge region (that is, each film-forming space) is provided in the corresponding film-forming chamber whose inside can be maintained in a vacuumed state. In order to prevent film-forming raw material gas including doping gas (dopant-supplying gas) used for the formation of a deposited film as a semiconductor layer in each glow discharge region (film-forming space) from being diffused or contaminated into the glow discharge region situated next thereto, a gas gate is provided between each adjacent film-forming chambers. The gas gate comprises a slit-like separation passage through which adjacent film-forming chambers are communicated, where separation gas such as Ar gas, H2 gas or the like is flown into the separation passage to form a gas flow of the separation gas whereby the adjacent film-forming chambers are isolated one from the other.
The film-forming method using the above-described roll-to-roll type plasma CVD apparatus is suitable for mass-producing functional deposited films or semiconductor devices such as photovoltaic elements including solar cells. However, there are such disadvantages as will be described below.
That is, because the space for forming a p-type or n-type semiconductor layer is substantially isolated from the space for forming an i-type semiconductor layer as above described, it is possible to prevent a dopant in the gaseous state used in the former space from being contaminated into the latter space.
However, for instance, at the time of forming an i-type semiconductor layer on a previously formed n-type semiconductor layer or after the i-type semiconductor layer is formed on the n-type semiconductor layer, there is an occasion in that for example phosphorous element (P) as the dopant in the n-type semiconductor layer is thermally diffused into the i-type semiconductor layer, where the n-i junction is weakened.
A solar cell whose photoelectric conversion semiconductor layer has a semiconductor junction including such weakened n-i junction has inferior initial characteristics such that the open-circuit voltage (Voc) and fill factor (F.F.) are insufficient and therefore, the initial photoelectric conversion efficiency is insufficient.
Besides, in the case of a solar cell having a photoelectric conversion layer with a p-i-n junction formed in accordance with the film-forming method using the foregoing roll-to-roll type plasma CVD apparatus, even when the solar cell has a satisfactory initial photoelectric conversion efficiency, it is liable to have such disadvantages as will be described in the following. That is, when the solar cell is continuously used under severe environmental conditions outdoors, there is a tendency in that the dopant in the p-type semiconductor layer or the n-type semiconductor layer is gradually thermally diffused into the i-type semiconductor layer to deteriorate the characteristics of the solar cell, where the photoelectric conversion efficiency of the solar cell is eventually deteriorated. Thus, the solar cell is insufficient in terms of the reliability.
As previously described, the film-forming method using the foregoing roll-to-roll type plasma CVD apparatus is suitable for mass-producing solar cells. However, there are still subjects to be improved in order to stably and efficiently mass-produce highly reliable solar cells having uniform solar cell characteristics and which exhibit a satisfactory photoelectric conversion efficiency which is hardly deteriorated even when continuously used under severe environmental conditions outdoors over a long period of time at a reasonable production cost.
Now, in the case where a plurality of solar cell modules [comprising a plurality of solar cells (photovoltaic elements) electrically serialized while being sealed by a sealing material] are electrically connected with each other in series connection or parallel connection into a unit, the solar cell module whose output electric current or output voltage is minimum becomes a rate-limiting factor to dominate the characteristics of the unit.
In this connection, it is very important to improve not only the average characteristics of all the solar cell modules involved but also variations among the solar cell modules in terms of the characteristics.
For this purpose, at a stage of forming the respective solar cell modules, it is necessary for the semiconductor layers used therein, which are an utmost decisive factor of dominating the characteristics of the solar cell module, to be made such that they are complete with respect to the characteristics. In addition, in order to reduce the production cost, it is also necessary to make the semiconductor layers have fewer defects so that neither disconnection nor short are occurred in the solar cell module, whereby the yield is improved.
In view of the above situation, there is an increased demand for improving the process for producing a photovoltaic element (a solar cell) by way of continuously forming a plurality of semiconductor layers on an elongated substrate (or a web substrate) which is continuously moving by means of plasma CVD, so that each of said plurality of semiconductor layers can be continuously and uniformly formed on the elongated substrate so as to have uniform characteristics and fewer defects over the entire of the elongated substrate.
The present invention has been accomplished in view of the foregoing technical subjects to be solved in the prior art.
An principal object of the present invention is to eliminate the foregoing problems in the prior art and to provide an improved process which enables one to efficiently produce a highly reliable semiconductor device having improved output characteristics.
The semiconductor device in the present invention includes a photovoltaic element including a solar cell, a photosensor, and the like.
Another object of the present invention is to provide a process for producing a highly reliable semiconductor device having a photoelectric conversion member and which has improved output characteristics at an improved yield, characterized in that a plurality of semiconductor layers to constitute said photoelectric conversion member are continuously formed so that each of said plurality of semiconductor layers has improved uniform characteristics and fewer defects.
A further object of the present invention is to provide a process for producing a highly reliable semiconductor device having a photoelectric conversion member formed by sequentially forming a p-type or n-type semiconductor layer composed of a non-single crystalline silicon series semiconductor material, an i-type semiconductor layer composed of a non-single crystalline silicon series semiconductor material, and an n-type or p-type semiconductor layer composed of a non-single crystalline silicon series semiconductor material by means of plasma CVD, characterized in that at least one i-type semiconductor layer as said i-type semiconductor layer is formed in a discharge chamber (or a film-forming chamber) by means of VHF (very high frequency) plasma CVD provided with a cathode electrode using a silicon atoms-containing raw material gas, wherein a VHF power of a wattage which is two times or less that of a VHF power required for decomposing 100% of said silicon atoms-containing raw material gas is applied to said cathode electrode.
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1. Field of the Invention
This invention relates to holders of decorative articles of wood for holding such articles during the preparative sawing process. More particularly, the invention relates to a holder or jig for holding a crown molding in place during the sawing process in producing miter joints therein.
2. Reported Developments
For certain decorative wood products, such as crown moldings, which are to be fitted to comers of various sizes, depending on ceiling heights and the requirement of how much of the corners are desired to be decorated, manufactured crown moldings produced in long pieces must be cut to the desired lengths. In cutting the manufactured crown moldings, two basic angles must be cut so that one end of the crown molding will conform to the ceiling, and the other end thereof will conform to the adjoining wall.
In preparing a crown molding, it is necessary to make two basic angle cuts, one on each end of the crown molding. The angle cut is typically about 52xc2x0 and about 38xc2x0 at the respective ends of the crown molding. The so-cut crown molding, when placed against a ceiling and an adjoining wall which form a 90xc2x0 angle between them, will form the hypotenuse of the triangle. In addition to the two basic angle cuts in a crown molding, it is necessary to make two bevel cuts at the ends of the crown molding by cutting across the grain of the crown molding with the miter blade angled to the crown molding. In making a compound miter cut at each end of the crown molding, a miter angle and a bevel angle is used at the same time.
To make the angle cut and the bevel cut simultaneously with a hand-held power saw, the prior art has provided a guide for cutting compound miters in crown moldings with a circular saw, such as disclosed in U.S. Pat. No. 4,907,482. While the device is inexpensive as compared to motorized miter boxes, it does has some drawbacks associated with hand-held power saws, such as handling difficulties of the power saws in a safe manner.
Motorized miter boxes have been developed for cutting workpieces at various angles and are being marketed by several manufacturers. Such motorized miter boxes typically comprise a work table for supporting the workpieces to be cut, a fence against which the workpieces are registered to hold the same during the cutting process, and a power saw reciprocable with respect to the work table to cut the workpieces supported by the work table. The work table and saw are angularly adjustable with respect to the fence so that the cut can be made at a desired angle. The motorized miter boxes enable the user to cut simple miters wherein the workpieces lay flat against the table and the fence; they also enable the user to cut compound miters wherein the workpiece is cut at an angle to its longitudinal axes while no major planar surface of the workpiece is parallel to either the work table or the fence. When compound miters are cut, filler blocks are used to provide a support surface oriented at an acute angle to both the work table and the fence. The filler blocks are typically secured to the work table or the fence by removable means, such as bolts and screws.
The prior art has further provided a miter box attachment for cutting crown and frame moldings with a miter saw as disclosed in U.S. Pat. No. 4,875,399. The reference uses a pair of jigs slidably mounted on opposite lateral edges on the table to be movable toward and away from the fence. The jig also includes a registration block which supports a workpiece in a cocked position against the fence for cutting of a compound miter.
In the prior art devices using a miter saw, filler blocks are used to hold and support the workpiece in place during the cutting process. The filler blocks are attached to the fence or worktable of the miter saw by clamps or other removable means. In U.S. Pat. No. 4,875,399 the filler blocks are replaced by a pair of slidably adjustable jigs to allow the workpiece to be moved toward or away from the fence of the miter saw. While the use of these means help to accomplish the desired result, the present invention accomplishes the desired result without the use of these implements by the provision of a simple crown molding holder used in conjunction with the miter saw.
According to the present invention, a workpiece holder, such as a crown molding holder, is provided for use in combination with a motorized miter box for cutting miter joints which require a simultaneous bevel and miter cutting operation.
The motorized box comprises:
a horizontal work table with a planar surface for supporting a workpiece;
a vertical fence extending from the work table and forming a 90xc2x0 angle therewith to provide a registration surface for the workpiece; and
a miter saw having a reciprocating arm with a tiltable cutting blade supported on the work table and registered against the vertical fence.
The workpiece holder is positioned on the horizontal work table and against the vertical fence on the worktable, the workpiece holder comprising:
a horizontal bottom plate slidably conforming to the planar surface of the work table;
a vertical side plate slidably conforming to the vertical fence and projecting away from the horizontal bottom plate enclosing a 90xc2x0 angle therewith, said horizontal bottom plate and said vertical side plate being integral with each other.
In order to securely hold a workpiece therein: the horizontal bottom plate of the workpiece holder is provided with a vertical integral rim extending longitudinally along the length of the horizontal bottom plate; and the vertical side plate is provided with a horizontal integral rim extending longitudinally along the length of the vertical side plate.
The workpiece holder is preferably made of 20 gauge galvanized steel which is magnetized to facilitate holding the workpiece holder against the fence of the miter table. The workpiece holder may also be made of aluminum and synthetic polymeric materials.
The workpiece holder may also be equipped with double-face pressure sensitive tape on the horizontal and vertical plates thereof to facilitate holding of the workpiece holder on the work table and against the fence of the miter box.
In use, the workpiece, such as a crown molding, is inserted into the work piece holder upside down with a portion of the molding intended to be cut extending away from and overhanging the workpiece holder so that the saw blade has no direct contact with the workpiece holder during the cutting process.
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Handguns can be divided into two principal classes, revolvers and "automatics". In the former, cartridges are loaded singly into the chambers of a cylinder which rotates to bring successive cartridges into alignment with the barrel and firing mechanism. In the latter a magazine or clip containing a plurality of cartridges may be slid as a unit into the butt of the weapon allowing the cartridges to feed automatically into the firing chamber or breech. The fired cartridges are automatically extracted.
Cartridges are also of two types, rimmed and rimless. The latter effectively have a single diameter so they stack with parallel axes; the former have bases at first ends with rims of diameter greater than the rest of the cartridge. The present invention relates to automatic weapons using rimmed cartridges.
In the prior art, there are magazines for rimless cartridges of several calibers and for rimmed cartridges of small calibers. The magazines for rimless cartridges generally relate to rifles (see, e.g., U.S. Pat. No. 3,726,038). The magazines for pistols generally use rimmless cartridges. Magazines for rimmed cartridges are known to exist for .22 and .38 special handguns. U.S. Pat. Nos. 2,510,831 and 2,895,248 are exemplary of .22 caliber magazines. The former shows a spring urged platform plate for lifting two columns of cartridges upward in the magazine. The latter shows a spring urged follower for lifting a single column of cartridges. A guide element is movable among three positions in order to accomodate .22 short .22 long and .22 long rifle cartridges. The guide element is essentially a wedge extending along a narrow side from the bottom to the top of the magazine.
Magazines for .38 special and .22 caliber handguns have been sold commercially. The .38 special magazine is exemplary. It has a spring urged follower for moving cartridges upward. The magazine holds a maximum of five cartridges. The cartridges rest in a single bananashaped column with the follower changing the angular orientation of the lower cartridge each time a bullet is fired. In this manner, the uppermost cartridge always maintains a proper orientation relative to the breech.
These prior art magazines are interesting, but have not taught how to make a magazine for a large caliber rimmed cartridge. Since a magazine for a handgun fits within the handle of the gun, geometry is an important aspect of any magazine design. Known magazines have not shown a combination of elements in a geometry usable in, for example, a .357 magnum. Furthermore, except for .22 caliber magazines, known magazines have not held more than five cartridges.
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Each year, accidental fires cause injuries and widespread loss of life throughout the country. Most such instances occur as a consequence of building fires, and the inability of individuals to escape therefrom in a fire situation. Victims include children who are frightened or confused, or who for some reason or other are unable to exit the building. However, adults are also oftentimes injured or killed as a result of panic or a physical disability which interferes with their ability to successfully operate emergency exits. Those trapped on upper floors of buildings are particularly vulnerable in fire situations.
Domesticated animals are even more at risk from the hazard of fire since they are incapable of operating the doors of buildings in which they are confined. Furthermore, in the case of horses, unless a fire is detected in its early stages and a suitable escape means provided, it is difficult and sometimes even impossible to save the animals because of their reluctance to leave the supposed security of their stalls.
Many attempts have been made to counter the fire hazard with such things as devices which detect the presence of fire and sound an alarm, automatic door-unlocking mechanisms, audio announcement systems, emergency doors with panic bars, and many similar and different systems. U.S. Pat. No. 4,539,555 for example, even describes a detection device that senses smoke or fire and automatically unbolts a normally locked escape door. However, such a system still suffers from the fact that a panicked victim in a smoke obscured environment sometimes lacks the presence of mind required to find and operate the door release. Unfortunately, the smoke, disorientation, panic, physical infirmity of those trapped, and various other circumstances oftentimes interfere with the safe escape of humans from buildings. In the case of animals, escape is often made difficult by the number of individual stalls involved, and the time required to lead animals therefrom. Despite the numerous devices, systems and other measures commonly employed to circumvent fire hazards, the fire toll continues to rise, and it is all to obvious that a serious problem still remains.
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Insulating glass units (IGUs) are used in windows to reduce heat loss from building interiors during cold weather. IGUs are typically formed by a spacer assembly sandwiched between glass lites. A spacer assembly usually comprises a frame structure extending peripherally about the unit, a sealant material adhered both to the glass lites and the frame structure, and a desiccant for absorbing atmospheric moisture within the unit. The margins or the glass lites are flush with or extend slightly outwardly from the spacer assembly. The sealant extends continuously about the frame structure periphery and its opposite sides so that the space within the IGUs is hermetic.
There have been numerous proposals for constructing IGUs. One type of IGU was constructed from an elongated corrugated sheet metal strip-like frame embedded in a body of hot melt sealant material. Desiccant was also embedded in the sealant. The resulting composite spacer was packaged for transport and storage by coiling it into drum-like containers. When fabricating an IGU the composite spacer was partially uncoiled and cut to length. The spacer was then bent into a rectangular shape and sandwiched between conforming glass lites.
Perhaps the most successful IGU construction has employed tubular, roll formed aluminum or steel frame elements connected at their ends to form a square or rectangular spacer frame. The frame sides and corners were covered with sealant (e.g., a hot melt material) for securing the frame to the glass lites. The sealant provided a barrier between atmospheric air and the IGU interior which blocked entry of atmospheric water vapor. Particulate desiccant deposited inside the tubular frame elements communicated with air trapped in the IGU interior to remove the entrapped airborne water vapor and thus preclude its condensation within the unit. Thus after the water vapor entrapped in the IGU was removed internal condensation only occurred when the unit failed.
In some cases the sheet metal was roll formed into a continuous tube, with desiccant inserted, and fed to cutting stations where “V” shaped notches were cut in the tube at corner locations. The tube was then cut to length and bent into an appropriate frame shape. The continuous spacer frame, with an appropriate sealant in place, was then assembled in an IGU.
Alternatively, individual roll formed spacer frame tubes were cut to length and “corner keys” were inserted between adjacent frame element ends to form the corners. In some constructions the corner keys were foldable so that the sealant could be extruded onto the frame sides as the frame moved linearly past a sealant extrusion station. The frame was then folded to a rectangular configuration with the sealant in place on the opposite sides. The spacer assembly thus formed was placed between glass lites and the IGU assembly completed.
IGUs have failed because atmospheric water vapor infiltrated the sealant barrier. Infiltration tended to occur at the frame corners because the opposite frame sides were at least partly discontinuous there. For example, frames where the corners were formed by cutting “V” shaped notches at corner locations in a single long tube. The notches enabled bending the tube to form mitered corner joints; but afterwards potential infiltration paths extended along the corner parting lines substantially across the opposite frame faces at each corner.
Likewise in IGUs employing corner keys, potential infiltration paths were formed by the junctures of the keys and frame elements. Furthermore, when such frames were folded into their final forms with sealant applied, the amount of sealant at the frame corners tended to be less than the amount deposited along the frame sides. Reduced sealant at the frame corners tended to cause vapor leakage paths.
In all these proposals the frame elements had to be cut to length in one way or another and, in the case of frames connected together by corner keys, the keys were installed before applying the sealant. These were all manual operations which limited production rates. Accordingly, fabricating IGUs from these frames entailed generating appreciable amounts of scrap and performing inefficient manual operations.
In spacer frame constructions where the roll forming occurred immediately before the spacer assembly was completed, sawing, desiccant filling, and frame element end plugging operations had to be performed by hand which greatly slowed production of units.
U.S. Pat. No. 5,361,476 to Leopold discloses a method and apparatus for making IGUs wherein a thin flat strip of sheet material is continuously formed into a channel shaped spacer frame having corner structures and end structures, the spacer thus formed is cut off, sealant and desiccant are applied, and the assemblage is bent to form a spacer assembly. U.S. Pat. No. 5,361,476 is incorporated herein by reference in its entirety.
U.S. Pat. No. 7,448,246 illustrates a mechanical crimper having crimping fingers, imposing folds along the spacer frame by mechanically connecting slides, cylinders, and the crimping fingers to the spacer frame while the spacer frame is being advanced. Stated another way, the crimping station included a number of slides and cylinders in addition to the crimping fingers that moved with the product by mechanically coupling the cylinders and fingers to the spacer while the material forming the spacer is advanced through the station. When the required number of crimps were complete, an additional cylinder was released from the spacer, allowing the crimper fingers and cylinders to be pulled back to a starting position by a mechanical spring. U.S. Pat. No. 7,448,246 is incorporated herein by reference in its entirety.
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In middle and late adulthood, all people experience a series of progressive alterations in body composition. The lean body mass shrinks and the mass of adipose tissue expands. The contraction in lean body mass reflects atrophic processes in skeletal muscle, liver, kidney, spleen, skin and bone.
These structural changes have been considered unavoidable results of the aging process. It has recently been proposed, however, that reduced availability of growth hormone in late adulthood may contribute to such changes. For example, after about the age of 30, the secretion of growth hormone by the pituitary gland tends to decline.
Pituitary growth hormone is a classical endocrine hormone which has profound effects on somatic growth and body composition. Growth hormone secretion is both pulsatile and diurnal. It is, thus, difficult to measure the 24-hour secretion of the hormone directly.
Growth hormone secretion, however, can be measured indirectly by measuring the serum concentration of insulin-like growth factor 1 (IGF-1; also known as somatomedin C) which is produced and released by the liver and perhaps other tissues in response to growth hormone, and which serves as an indicator of overall growth hormone secretion. Serum IGF-1 concentrations increase in response to both endogenously and exogenously administered growth hormone, have little diurnal variation, and are low in the case of growth hormone deficiency. Serum IGF-1 concentrations also decline with advancing age in healthy adults. Less than five percent of healthy men 20 to 40 years old have serum IGF-1 values below 350 U per liter (1 unit=240 ng); however, 30 percent of healthy men over 60 have values below this figure. Decline, with advanced age, of serum IFG-1 concentration has been correlated with the decline or disappearance of the nocturnal pulses of growth hormone secretion. If the serum concentration of IGF-1 falls below about 350 U per liter in older adults, no spontaneous circulating pulses of growth hormone can be detected by currently available radioimmunoassay methods. The concomitant decline in serum concentrations of both hormones supports the view that the decrease in IGF-1 results from diminished growth hormone secretion. At all ages, it has been found that serum level of IGF-1 is inversely correlated with adiposity.
Diminished secretion of growth hormone is accompanied not only by a fall in the serum IGF-1 concentration, but also by atrophy of the lean body mass and expansion of the mass of adipose tissue. These alterations in body composition caused by growth hormone deficiency can be reversed by replacement doses of the hormone, as shown by experiments in rodents, children and adults 20 to 50 years old. These findings suggest that the atrophy of the lean body mass and its component organs and the enlargement of the mass of adipose tissue that are characteristic of the elderly result, at least, in part, from diminished secretion of growth hormone. If so, age-related changes in the body composition should be correctable, in part, by the administration of human growth hormone, now readily available as a biosynthetic product. Several studies have now confirmed that beneficial results can be obtained from growth hormone treatment. See, for example, Rudman et al., New England Journal of Medicine, vol. 323 (1990) pp. 1-5, in which healthy aged men who had IGF-1 levels below 350 U/L were administered growth hormone. See, also, Salomon et al., N. Engl. J. Med., vol. 321 (1989) pp. 1797-1803; Cuneo et al., J. Appl. Physiol., vol. 70 (1991) pp. 688-694; Cuneo et al., J. Appl. Physiol., vol. 70 (1991) pp. 695-700 et al J. Clin. Endocrinol. Metab., vol. 70 (1990) pp. 519-527.
Much of the focus of such studies has centered on changes in muscle and bone associated with growth hormone levels. See, for example, Brixen et al., J. Bone Min. Res., vol. 5 (1990) pp. 609-618; Stracke et al., Acta Endocrinol., vol. 107 (1984) pp. 16-24; Chenu et al., Bone, vol. 11 (1990) pp. 81-86. At least one study suggests that IGF-1 itself has an independent effect on bone matrix formation; see, Hock et al., Endocrinol., vol. 122 (1988) pp. 254-260. It has been found that some bone deterioration associated with age, e.g., kyphosis, is irreversible, thus supporting a view that growth hormone might be beneficially used as a prophylactic.
One marker of bone remodeling/formation is the serum level of osteocalcin, a vitamin-K dependent protein synthesized in bone. Pun et al., Bone, , vol. 11 (1990) pp. 397-400. Measurement of circulating levels of osteocalcin can provide information on bone turnover. The Pun et al. study found a significant correlation between serum osteocalcin levels and IGF-1, indicating that IGF-1 is a determinant of serum osteocalcin.
While studies suggest potential benefits to body composition of growth hormone administration, some serious concerns remain regarding the effects of long term administration of growth hormone. Numerous studies suggest both beneficial and harmful effects on metabolic function. Toxic, or potentially toxic, side-effects of prolonged growth hormone treatment (i.e., daily administration over several weeks' time) which have been observed with the administration of moderate or high doses (i.e., doses above normal blood levels) include stimulation of neoplastic growth, acromegaly, amenorrhea, flushing and nausea, "dawn" phenomena (a condition of insulin insufficiency which is very dangerous for diabetics), either hyperglycemia or hypoglycemia in diabetics, and fluid retention caused by kidney glomeruli retention of sodium. (Scientific American Medical Information Text, Eds. E. Rubinstein and D. Fedman, Scientific American Soc. (1992)) Thus, similar to treatment with other hormones, long-term use is often a balancing act.
Moreover, efforts to administer IGF-1 rather than growth hormone have also raised concerns of harmful effects. Potential side-effects of prolonged (as defined above for growth hormone) treatment with moderate or high doses (as defined above for growth hormone) of IGF-1 include abdominal bloating, indigestion and nausea, and alteration in cellular insulin receptor sites. The latter effect could result in changes in glucose or fatty acid oxidation, as well as either insulin insufficiency or excess. Such effects are quite dangerous for diabetics. (Scientific American Medical Information Text, Eds. E. Rubinstein and D. Fedman, Scientific American Society (1992))
In addition to diminished growth hormone levels with increasing age, other studies have reported age-linked changes in the activity of enzymes and cofactors involved, for example, in the tricarboxylate cycle and lipid oxidation. One such cofactor is carnitine (.beta.-hydroxy-.gamma.-N-trimethylammounium butyrate). Carnitine is required for fatty acid oxidation a major source of energy for normal body function. Carnitine has two critical functions in the cell, namely, (1) to stimulate fatty acid oxidation by transporting acyl groups across the inner mitochondrial membrane, resulting in ATP formation, and (2) to remove extra or "toxic" acyl groups from the mitochondria and cell as carnitine esters.
Carnitine is present in both serum and urine in free and esterified forms, although in human beings carnitine esters are preferentially excreted while free carnitine is reabsorbed by the kidney. Normal total serum carnitine concentrations range from 31-79 .mu.M for men and 25-69 .mu.M for women, and free carnitine from 28-68 .mu.M for men and 21-57 .mu.M for women. Carnitine deficiency is defined as a total serum carnitine of 20 .mu.M or lower, or a free carnitine of 20 .mu.M or lower. The ratio of esterified carnitine, i.e., carnitine esters, to free carnitine, E/F, is a relatively good indicator of mitochondrial oxidation and ATP formation. An E/F ratio of 0.4 or higher is indicative of free carnitine insufficiency and indicates poor oxidation of fatty acids and low ATP production. An abnormally high E/F ratio may also indicate increased removal of toxic acyl groups because of a genetic enzyme defect, ingestion of potentially toxic compounds (e.g., valproic acid), or a generalized decrease in carnitine-related metabolism associated with, e.g., aging. Related animal studies have indicated that both lipid oxidation and carnitine levels are decreased in aged rats. (Hansford et al., Mechanisms of Aging and Dev., vol. 19 (1982) pp. 191-201.)
Carnitine has also been shown to be important in normal growth. (S. C. Winter et al., Am. J. Dis. Child. vol. 141 (1987) p. 660) For example, children with carnitine deficiency have stunted growth which normalizes with carnitine repletion.
Thus, the prior art teaches age-linked decreases in body levels of growth hormone. The prior art also teaches the use of growth hormone to retard bone loss associated with aging, and that IGF-1 concentration serves as an indicator for overall growth hormone secretion and that osteocalcin concentration is an indicator of bone formation. The art has, however, not provided any link between in vivo carnitine level and IGF-1 or bone loss.
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1. Technical Field
The present invention generally relates to the field of microprocessor development, and more particularly to techniques for automating the production of a hierarchical processor/architecture description language representation of a microprocessor.
2. Background Information
A microprocessor acts as the “brain” of a computer, processing instructions at a high rate; the prior art is replete with various microprocessor designs, architectures, configurations, processing schemes, and coding techniques. The power of a microprocessor is its ability to perform instructions very quickly. In order to process an instruction, a microprocessor requires the information to be in a particular format, called a “machine language.” This machine language, which is the basic binary language for the computer instructions, differs depending on the specific microprocessor. Although microprocessors utilize binary machine language, it is much easier to write instructions for a computer if the instructions are alphanumeric, a format more easily understood by humans. This can be done through the use of “high-level languages,” such as C++ and BASIC, or assembly language. Assembly language is more directly related to a microprocessor's machine language as each assembly language instruction represents a machine language instruction with mnemonic text instead of a binary format.
Microprocessor designers balance many considerations during the development of a microprocessor. One important consideration is the actual functionality of the microprocessor. A microprocessor must have a plurality of instructions to be useful. The term “instruction set” is used for the set of all of the instructions utilized by a microprocessor. The description of the instruction set and the functions of each instruction is called an “instruction set architecture” (“ISA”). An ISA is generally viewed in terms of three portions: the assembly language mnemonic for each of the instructions, the machine language encoding of the instructions, and the operation of the instruction.
Designers traditionally describe the ISA of a processor/architecture in terms of an opcode summary table. An opcode summary table is a table which lists the assembly language mnemonic for each instruction, the machine language bit pattern encoding for each instruction, and the position of the operands within the instruction.
Each bit in an instruction has a different function. The portion of the instruction that determines which instruction is to be performed is termed the opcode. For a simple instruction set, the opcode may take 6 bits out of the 32 bits available for each instruction. The operand is the remainder of the instruction and determines, for example, what register is being operated upon, or what memory location is to be accessed.
When designing a new microprocessor, the designers must be able to test their designs to find any problems and optimize the performance. Testing the designs involves the use of assemblers, compilers, and simulators (“programming tools”) to test the operation of the microprocessor. An assembler is a program that translates assembly language mnemonics to the processor's machine language. A compiler transforms a high-level language, such as BASIC or C++, to the processor's machine language. A simulator simulates the operation of the microprocessor by performing each function of the microprocessor on an already existing computing platform. A simulator thus enables one to test a microprocessor without having to first physically build it.
To automate the creation of those programming tools, several Architecture Description Languages (“ADL”) have been developed, such as nML, ISDL, LISA, and RADL. It is possible to describe each instruction using an ADL. For many instruction sets, however, similar instructions have similar machine language formats with common shared fields. Using an ADL, one can group similar instructions together to create a more compact representation of the processor. This compact representation is also less prone to errors because similar groups of instructions need be described only once, with only the differences further delineated.
The power of an ADL lies in the fact that, using an ADL description of a microprocessor, one can automatically create various programming tools for that processor. In order to create, for example, an assembler for a microprocessor, one may write a program in ADL that describes the microprocessor. Then, an assembler generator could be used to create an assembler from the ADL description of the microprocessor. In order to create a simulator, one would also need to input the behavior of each instruction into the ADL description into the simulator generator.
In the past, the creation of an ADL description of a microprocessor was manually performed by a person, given the assembly language instructions and its machine language representation. However, when developing new microprocessors, the manual creation of these programs can delay the development of the new microprocessors by two to three weeks.
After the programming tools are created, the new microprocessor is tested. Once tested, the design may be improved in various ways, including modifying the instruction set. Once the product is improved, new programming tools must be created, which results in additional delays associated with the re-coding of the ADL. Furthermore, the ADL code must be debugged before it can reliably be used to test the microprocessor.
Another problem with the ADL is the learning curve. A microprocessor designer would have to learn how to code in a language that may be new to them. A microprocessor designer may be more concerned with producing the physical embodiment of the microprocessor chip, rather than the production of programming tools. Many designers are also more comfortable with the traditional methods of describing a microprocessor, such as an opcode summary table. Thus, many designers spend their time producing documentation related to the operation of the microprocessor.
To facilitate the design of microprocessors, it is desirable to automate the process of producing an ADL representation of a microprocessor.
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Electronic devices commonly have some type of bulk storage device available to them. A common example is a hard disk drive (HDD). HDDs are capable of large amounts of storage at relatively low cost, with current consumer HDDs available with over one terabyte of capacity.
HDDs generally store data on rotating magnetic media or platters. Data is typically stored as a pattern of magnetic flux reversals on the platters. To write data to a typical HDD, the platter is rotated at high speed while a write head floating above the platter generates a series of magnetic pulses to align magnetic particles on the platter to represent the data. To read data from a typical HDD, resistance changes are induced in a magnetoresistive read head as it floats above the platter rotated at high speed. In practice, the resulting data signal is an analog signal whose peaks and valleys are the result of the magnetic flux reversals of the data pattern. Digital signal processing techniques called partial response maximum likelihood (PRML) are then used to sample the analog data signal to determine the likely data pattern responsible for generating the data signal.
HDDs have certain drawbacks due to their mechanical nature. HDDs are susceptible to damage or excessive read/write errors due to shock, vibration or strong magnetic fields. In addition, they are relatively large users of power in portable electronic devices.
Another example of a bulk storage device is a solid state drive (SSD). Instead of storing data on rotating media, SSDs utilize semiconductor memory devices to store their data, but include an interface and form factor making them appear to their host system as if they are a typical HDD. The memory devices of SSDs are typically non-volatile flash memory devices.
Flash memory devices have developed into a popular source of non-volatile memory for a wide range of electronic applications. Flash memory devices typically use a one-transistor memory cell that allows for high memory densities, high reliability, and low power consumption. Changes in threshold voltage of the cells, through programming of charge storage or trapping layers or other physical phenomena, determine the data value of each cell. Common uses for flash memory and other non-volatile memory include personal computers, personal digital assistants (PDAs), digital cameras, digital media players, digital recorders, games, appliances, vehicles, wireless devices, cellular telephones, and removable memory modules, and the uses for non-volatile memory continue to expand.
Unlike HDDs, the operation of SSDs is generally not subject to vibration, shock or magnetic field concerns due to their solid state nature. Similarly, without moving parts, SSDs have lower power requirements than HDDs. However, SSDs currently have much lower storage capacities compared to HDDs of the same form factor and a significantly higher cost per bit.
For the reasons stated above, and for other reasons that will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternative bulk storage options.
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Many conventional filter assemblies include a hollow, cylindrical filter which comprises a cylindrical, pleated filter medium sandwiched between and bonded to impervious end caps. At least one of the end caps has a central aperture through which a fluid line communicates with the interior of the filter. Fluid to be filtered is directed through the filter medium from the outside to the inside and the filtered fluid is then removed from the interior of the filter via the fluid line.
As the fluid flows outside-in through the filter, contaminants, such as particulates, accumulate on the outside surface of the filter medium. Once a sufficient accumulation of contaminants has caked onto the outside surface of the filter medium, flow through the filter is significantly impeded. At this point, the filter should be removed from the filter assembly and replaced with a new filter. Unfortunately, with the accumulation of contaminants caked on the outside of the filter medium, removing and replacing the filter can result in the release of some of the accumulated contaminants. These contaminants can then re-enter the system fluid and cause severe wear or other related problems.
A filter assembly having a filter with one closed end cap allows the fluid to be filtered to be directed from the inside-out and significantly diminishes this problem. The contaminants accumulate on the inside surface of the filter medium and therefore are contained within the filter by the medium and closed end cap. Consequently, the filter may be removed and replaced conveniently without release of the accumulated contaminants trapped inside the filter.
Unfortunately, conventional filter assemblies designed for inside-out have several additional drawbacks. For example, in order to force fluid through the filter, the pressure of the fluid inside the filter must be greater than the pressure of the fluid outside the filter. This difference in pressure forces the end caps away from the filter medium. If the force becomes great enough, the bond between the end caps and the filter medium can rupture, causing contaminated fluid to bypass the filter medium. Because of this force, conventional filter assemblies frequently use two open end caps with compression seals and/or an auxiliary spring force to help keep the filter in compression to prevent rupture of the end cap bonds. However, the open end caps will not contain the accumulated contaminant on the inside of the filter.
Inside-out flow is also more likely to stretch and misshape the pleats of the filter medium than outside-in flow. Misshaping the element modifies its porous characteristics, making it useless long before rupture occurs. Further, both of these problems, i.e, rupture of the end cap bonds and misshaping of the element, are heightened by flow disturbances, such as flow surges, which may typically be encountered by the filter assembly.
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This application claims the priorities of Japanese Patent Application Nos. 10-32214, 10-32215, and 10-32216, each filed on Jan. 29, 1998, and Japanese Patent Application No. 10-98376 filed on Mar. 26, 1998 which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a three-dimensional image scanner for capturing three-dimensional form information and pattern information of an object to be measured and generating a three-dimensional image of the object; and, in an optical apparatus in which a light source and a heat-sensitive section are accommodated in a common housing, to a heat-insulating device provided with a heat-insulating partition for inhibiting the heat generated by the light source from being transmitted to the heat-sensitive section.
2. Description of the Prior Art
In the fields of computer graphics, plastic surgery, and the like, a three-dimensional image scanner is employed as an input device for three-dimensional images. In general, the three-dimensional image scanner is configured such as to capture three-dimensional form information and pattern information of an object to be measured and generate a three-dimensional image of the object according to thus captured three-dimensional form information and pattern information.
Though a three-dimensional measuring device using a probe, an optical cutting device using an optical sensor, or the like can be chosen as a device for capturing the three-dimensional form information of the object to be measured, the three-dimensional form information can easily be captured in a short time if a moire device is employed.
When a grating shadow type moire device, which is a typical example of moire device, is used, then the following problems may occur.
Namely, as shown in FIG. 5, a grating shadow type moire device is configured such that light from a point light source P1 irradiates an object to be measured 2 by way of a reference grating 102, and a deformed grating image formed on the object 2 is observed through the reference grating 102 at an observing point P2, so as to yield an image formed with moire fringes. In this grating irradiation type moire device, however, the size of the measurable object 2 is restricted by the size of the reference grating 102, and the object 2 is needed to be placed in front of the reference grating 102, whereby there may occur a problem that the degree of freedom in measurement decreases.
In view of such circumstances, it is a first object of the present invention to provide a three-dimensional image scanner which can capture three-dimensional form information of an object to be measured easily in a short time with a high degree of freedom in measurement.
Further, since the reference grating 102 exists, the above-mentioned grating irradiation type moire device cannot be used, as it is, for capturing the pattern information of the object 2. For capturing this information, it is necessary to take a two-dimensional image of the object 2 with the reference grating 102 being removed so that no moire fringes are formed. Since the reference grating 102 is considerably large, it cannot easily be removed.
In view of such circumstances, it is a second object of the present invention to provide a three-dimensional image scanner which can easily capture pattern information of an object to be measured, while being able to capture three-dimensional form information of the object easily in a short time with a high degree of freedom in measurement.
In an optical apparatus provided with a light source such as lamp, like the moire device mentioned above, the light source acts as a heat source so as to thermally influence its surroundings. In the case where a heat-sensitive section such as a light-receiving element or control circuit which is likely to be influenced by temperature is accommodated in the same housing with the light source, it is necessary to provide a heat-insulating structure for inhibiting the heat generated by the light source to be transmitted to the heat-sensitive section.
Therefore, an exhaust fan has conventionally been disposed at an outer wall portion of the housing, so as to discharge the air heated by the light source to the outside.
Simply providing an exhaust fan, as in the conventional cases, may not yield sufficient heat-insulating effects, however.
For example, in the case where a grating projection type moire device which is configured such as to capture not only the three-dimensional form information but also pattern information of an object to be measured employs a structure for illuminating the object with an illumination lamp, the illumination lamp often has to be disposed relatively close to the imaging section of a CCD camera or the like. In such a case, it is difficult to sufficiently inhibit the heat generated by the illumination lamp from being transmitted to the imaging section by simply providing an exhaust fan. Such a problem can similarly occur in other optical apparatus as well.
In the case employing a configuration in which a first partition for separating the light source and the heat-sensitive section from each other and a second partition disposed on the light source side of the first partition are disposed such as to form a cooling passage for guiding the heat generated by the light source to the exhaust fan, the ventilation efficiency in the cell defined by the first partition can be enhanced. This can suppress the temperature rise in the first partition, thereby inhibiting the heat from being transmitted to the heat-sensitive section through the partition to some extent.
In the case where the heat-sensitive section is extremely sensitive to heat, as in the case of CCD camera or the like, there is a demand for further effectively inhibiting the heat from being transmitted to the heat-sensitive section.
In view of such circumstances, it is a third object of the present invention to provide, in an optical apparatus in which a light source and a heat-sensitive section are accommodated in a common housing, a heat-insulating device which can effectively inhibit the heat generated by the light source from being transmitted to the heat-sensitive section.
The three-dimensional image scanner in accordance with a first aspect of the invention achieves the first object of the present invention by capturing three-dimensional form information by using a grating projection type moire device.
Namely, the three-dimensional image scanner in accordance with the first aspect of the present invention is a three-dimensional image scanner for capturing three-dimensional form information and pattern information of an object to be measured and generating a three-dimensional image of the object according to thus captured three-dimensional form information and pattern information,
wherein the three-dimensional form information is captured by a grating projection type moire device.
Preferably, the grating projection type moire device comprises grating moving means for moving at least one of a projection grating provided in a projection optical system of the grating projection type moire device and an observation reference grating provided in an observation optical system of the grating projection type moire device in a direction orthogonal to grating lines of both of the gratings within a plane orthogonal to optical axes of both of the optical systems.
Preferably, the grating projection type moire device further comprises fringe scanning means for determining, according to a plurality of sets of three-dimensional form information captured at individual moving positions of at least one of the projection grating and observation reference grating moved by the grating moving means, an irregular form of each part of the tree-dimensional form information.
Here, xe2x80x9cgrating projection type moire devicexe2x80x9d refers to a moire device comprising a projection optical system and an observation optical system, whose optical axes are in parallel to each other, in which an image of a projection grating is projected by the projection optical system onto the object to be measured, and the deformed grating image formed on the object is focused on the observation reference grating by the observation optical system, such that the resulting moire fringes are observed.
The three-dimensional image scanner in accordance with a second aspect of the present invention captures the three-dimensional form information by using a grating projection type moire device, and the pattern information by using an observation optical system of the grating projection type moire device, thereby achieving the second object.
Namely, the three-dimensional image scanner in accordance with the second aspect of the present invention is a three-dimensional image scanner for capturing three-dimensional form information and pattern information of an object to be measured and generating a three-dimensional image of the object according to thus captured three-dimensional form information and pattern information,
wherein the three-dimensional form information is captured by a grating projection type moire device, and the pattern information is captured by an observation optical system of the grating projection type moire device.
Preferably, the grating projection type moire device further comprises grating retracting means for retracting at least one of a projection grating provided in a projection optical system of the grating projection type moire device and an observation reference grating provided in the observation optical system to a position deviated from an optical path of the optical system corresponding thereto when capturing the pattern information.
The three-dimensional image scanner in accordance with the third aspect of the present invention captures the three-dimensional form information by using a grating projection type moire device, and the pattern information by using an observation optical system of the grating projection type moire device, and an illumination lamp exclusively used for irradiating the object to be measured is turned on when capturing the pattern information, thereby achieving the second object.
Namely, the three-dimensional image scanner in accordance with the third aspect of the present invention is a three-dimensional image scanner for capturing three-dimensional form information and pattern information of an object to be measured and generating a three-dimensional image of the object according to thus captured three-dimensional form information and pattern information,
wherein the three-dimensional form information is captured by a grating projection type moire device, and the pattern information is captured by an observation optical system of the grating projection type moire device; and
wherein, when capturing the pattern information, an illumination lamp different from a projection lamp provided in a projection optical system of the projection type moire device is turned on such as to irradiate the object.
Preferably, the projection lamp is turned off when the illumination lamp is turned on.
Preferably, when capturing the pattern information, an observation reference grating provided in the observation optical system is retracted to a position deviated from an optical path of the observation optical system.
The heat-insulating device in accordance with a fourth aspect of the present invention is a heat-insulating device in an optical apparatus in which a light source and a heat-sensitive section are accommodated in a common housing while being separated from each other by a heat-insulating partition such as to inhibit the heat generated by the light source from being transmitted to the heat-sensitive section,
wherein the heat-insulating partition comprises at least two partition walls forming a cooling/heat-insulating path.
Here, the xe2x80x9clight sourcexe2x80x9d is not restricted to any particular kind of light sources as long as it is a heat radiation type light source which may adversely affect the heat-sensitive section.
The xe2x80x9cheat-sensitive sectionxe2x80x9d is not restricted to any particular element as long as it may adversely be affected by the heat generated by the light source, and examples thereof include light-receiving elements, electric circuits, control circuits, precision instruments, and the like.
Preferably, the cooling/heat-insulating path is provided with an intake port for forcibly causing air from outside to flow through the cooling/heat-insulating path, and an exhaust unit.
Preferably, the heat-sensitive section comprises a light-receiving element; and
at least one of the partition walls is constituted as a light-shielding wall for inhibiting light from the light source from being made incident on the light-receiving element.
The heat-insulating device may be configured such that the optical apparatus comprises a grating projection type moire device for capturing three-dimensional form information and pattern information of an object to be measured;
the light source comprises an illumination lamp for irradiating the object upon capturing the pattern information; and
the light-receiving element comprises an imaging section.
Since the three-dimensional image scanner in accordance with the first aspect of the present invention is configured such that the three-dimensional form information is captured by a grating projection type moire device, it can attain the following effects.
The grating projection type moire device does not necessitate a reference grating such as that in a grating shadow type moire device, whereby it will be sufficient if a virtual reference grating surface is set at a position conjugate with both of the projection grating and observation reference grating. This virtual reference grating surface has a size sufficient for the object to be measured, whereby the size of the object to be measured would not be restricted by the virtual reference grating surface. Also, the object to be measured can be disposed fore and aft through the virtual reference grating surface. As a consequence, the use of the grating projection type moire device increases the degree of freedom in measurement of the object. Also, since it is a moire device, the three-dimensional form information can easily be captured in a short time.
Therefore, the three-dimensional image scanner in accordance with the first aspect of the present invention can capture the three-dimensional form information of the object to be measured easily in a short time with a high degree of freedom in measurement.
In the above-mentioned configuration, in the case where the grating projection type moire device comprises grating moving means for moving at least one of a projection grating provided in a projection optical system of the grating projection type moire device and an observation reference grating provided in an observation optical system of the grating projection type moire device in a direction orthogonal to grating lines of both of the gratings within a plane orthogonal to optical axes of both of the optical systems, irregularities of the object can easily be determined when the directivity of change in moire fringes with respect to the movement of the grating is observed.
In this case, the grating moving means may move the projection grating alone, the observation reference grating alone, or both of them if they are not moved in the same phase.
Since the three-dimensional image scanner in accordance with the second aspect of the present invention is configured such that the three-dimensional form information is captured by a grating projection type moire device, and the pattern information is captured by an observation optical system of the grating projection type moire device, it can attain the following effects.
Namely, not only this three-dimensional image scanner can achieve the effects obtained by the three-dimensional image scanner in accordance with the first aspect of the present invention, but also it is unnecessary to remove a large reference grating in the grating projection type moire device such as that in the grating irradiation type moire device, in regard to the capturing of pattern information, whereby the pattern information can easily be captured by the observation optical system of the grating projection type moire device.
Therefore, the three-dimensional image scanner in accordance with the second aspect of the present invention can capture the three-dimensional form information of the object to be measured easily in a short time with a high degree of freedom in measurement, and can easily capture the pattern information of the object as well.
In this configuration, the pattern information has to be captured in the state where the object to be measured is placed in the state where no moire fringes are formed. Employable as a specific structure therefor is a structure comprising grating retracting means for retracting at least one of a projection grating provided in a projection optical system of the grating projection type moire device and an observation reference grating provided in the observation optical system to a position deviated from an optical path of the optical system corresponding thereto when capturing the pattern information. Since each of the projection grating and observation reference grating is much smaller than the reference grating of the grating irradiation type moire device, they can easily be retracted.
Since the three-dimensional image scanner in accordance with the third aspect of the present invention is configured such that the three-dimensional form information is captured by a grating projection type moire device, the pattern information is captured by an observation optical system of the grating projection type moire device, and an illumination lamp different from a projection lamp provided in a projection optical system of the projection type moire device is turned on when capturing the pattern information such as to irradiate the object, it can attain the following effects.
Namely, not only this three-dimensional image scanner can achieve the effects obtained by the three-dimensional image scanner in accordance with the first aspect of the present invention, but also it is unnecessary to remove a large reference grating in the grating projection type moire device such as that in the grating irradiation type moire device, in regard to the capturing of pattern information, whereby the pattern information can easily be captured by the observation optical system of the grating projection type moire device. Here, since an illumination lamp different from a projection lamp provided in the projection optical system of the projection type moire device is turned on when capturing the pattern information such as to irradiate the object, the shadow of the projection grating formed on the object by the projection lamp can be made substantially unremarkable, whereby the pattern information of the object formed with no moire fringes can be captured even when the projection grating and the observation reference grating are not retracted to a position deviated from the optical paths of the projection optical system and observation optical system.
Therefore, the three-dimensional image scanner in accordance with the third aspect of the present invention can capture the three-dimensional form information of the object to be measured easily in a short time with a high degree of freedom in measurement, and can easily capture the pattern information of the object as well.
In this configuration, though the projection lamp may be kept turned on while the illumination lamp is turned on, if the projection lamp is turned off, then no shadow of the projection grating will be formed, whereby the pattern information can be captured with higher accuracy.
Further, in this configuration, if the observation reference grating is retracted to a position deviated from the optical path of the observation system path when capturing the pattern information, then a sufficient quantity of light incident on the imaging device of the observation optical system can be secured. Also, in the case where the imaging device is a CCD camera or the like, artificial moire fringes can be prevented from occurring between the observation reference grating and the CCD or the like, whereby the pattern information can be captured with much higher accuracy.
Since the heat-insulating device in accordance with the fourth aspect of the present invention is configured such that, between a light source and a heat-sensitive section, a heat-insulating partition comprising at least two partition walls forming a cooling/heat-insulating path in order to inhibit the heat generated by the light source from being transmitted to the heat-sensitive section is provided, it can effectively inhibit the heat generated by the light source from being transmitted to the heat-sensitive section.
In this configuration, if the cooling/heat-insulating path is formed with an intake port for forcibly causing the outside air to flow through the cooling/heat-insulating path, and an exhaust unit, then the air flow from the intake port to the exhaust unit can be made very smooth, whereby the heat exhaust efficiency can be enhanced.
Also, in this configuration, when the heat-sensitive section comprises a light-receiving element, if at least one of the partition walls forming the cooling/heat-insulating path is formed as a light-shielding wall for inhibiting light from the light source from being made incident on the light-receiving element, then the heat-insulating device can also have a light-shielding function.
Further, in the case where the optical apparatus comprises a grating projection type moire device for capturing three-dimensional form information and pattern information of an object to be measured; the light source comprises an illumination lamp for irradiating the object upon capturing the pattern information; and the light-receiving element comprises an imaging section; the illumination lamp and the imaging section are often disposed relatively close to each other. Since the illumination lamp has a large heating value, whereas the imaging section is likely to be influenced by heat, employing the configuration in accordance with the fourth aspect of the present invention is effective in particular.
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a) Field of the Invention
The invention is directed to so-called laser-compatible NIR marker dyes based on polymethines for use in optical, in particular, fluorescence optical determination and detection methods. Typical applications of the process are based on the reaction of dye marked antigens, antibodies, ligands or DNA segments with the respective complementary species.
Possible uses exist, for example, in the fields of medicine, pharmaceutics and in the areas of life science, materials science, in environmental monitoring and in the detection of organic and inorganic micro-samples occurring naturally and in technological contexts, but they are not limited to the aforementioned fields.
b) Description of the Related Art
The usability of polymethines as NIR markers has been known of for a long time; they distinguish themselves by their strong absorption maxima which can easily be transposed into the NIR range (Fabian, J.; Nakazumi, H.; Matsuoka, M.: Chem. Rev. 1992, 92, 1197). With a suitable substituent pattern and pi-electron system and at a sufficient quantum yield they also fluoresce in the red and near infrared (NIR) range. Correspondingly, these compounds are widely used in different technological fields: as sensitizers in AgX materials, as laser dyes, as quantum counters, as indicator dyes in sensor technology, as light absorbers in writable CDs and last but not least as biomarkers (xe2x80x9cNear-Infrared Dyes for High Technology Applicationxe2x80x9d, published by Daehne, S.; Resch-Genger, U.; Wolfbeis, O.-S., Kluwer, Academic Publishersxe2x80x94Dordrecht/Boston/Londonxe2x80x941998).
The number of polymethines used as biomarkers is limited. So far, only the trimethine Cy3 derived from astraphloxine (DE 410 487), the vinylogous pentamethine Cy5 and the doubly vinylogous heptamethine Cy7 with absorption maxima at approximately 550 nm, approximately 650 nm and approximately 750 nm have so far found wide commercial application in this manner (U.S. Pat. No. 5,627,027). Also available are the polysulfonated trimethine Cy3.5 derived from the commercial hepatmethine xe2x80x9cIndocynaninegreenxe2x80x9d or xe2x80x9cCardio Greenxe2x80x9d and the pentamethine Cy5.5 (U.S. Pat. No. 5,569,766). Heptamethines with aliphatic bridges in the polymethine chain have been developed by Patonay (U.S. Pat. No. 5,800,995). All commercial biomarkers are characterized by terminal heteroaromatics derived from indene or heteroindene (Fischer""s base). If methylsubstituted cycloimmonium salts are used as terminal polymethine building blocks, it is necessary to arrange at least five sequential sp2 hybridized carbon atoms (pentamethines) between the heterocycles to generate absorption maxima at the boundary to the NIR range.
The NIR polymethines used in technology as biomarkers have the distinct disadvantage that lengthening the polymethine chain increases the opportunities for nucleophilic or electrophilic attack on the chain, in consequence of which the pi-system is destroyed. Further disadvantages of these marker dyes consist in their insufficient photostability and stability in storage, complicated synthesis and purification stages, low absorption coefficients/low fluorescent quantum yields as well as undesired changes of their optical properties in the presence of or after bonding with proteins or nucleic acid oligomeres. For example, a reduction of the fluorescent quantum yield of Cy5 has been described for the covalent bonding with different albumins (Oswald, B.; Patsenker, L.; Duschl, J.; Szmacinski, H.; Wolfbeis, O. S.; Terpeschnig, E.; Bioconjugate Chem. 1999, 10, 925-931).
The use of pyrylium and benzopyrylium heterocycles or the corresponding mesomeric chromenes as terminal end groups in marker dyes in biologically relevant systems is so far not known in the art. This is due to the extreme sensitivity to hydrolysis of these pi-deficient aromatics, especially in an aqueous basic environment (H. Lietz, G. Haucke, P. Czerney, B. John, J. Prakt. Chem., 1996, 338, 725-730).
Telfer et al. (U.S. Pat. No. 5,262,549) describe symmetrical trimethines based on 2-alkyl substituted benzopyrylium salts for the use as NIR absorbers in polimeric media with a reduced tendency towards aggregation in these media.
The primary object of the invention is to create NIR marker dyes based on polymethine which have a high degree of photostability and stability in storage as well as a high fluorescent yield and which can be excited to fluorescence in the easiest possible manner by means of laser radiation in the longwave visible or NIR spectral range, particularly with light of a helium/neon or diode laser.
The present invention describes marker dyes based on non-symmetrical polymethines which contain a substituted xcfx89-(benz[b]pyran-4-ylidene)alk-1-enyl) unit of general formula (I),
where Z is a substituted derivative of benzooxazol, benzothiazol, 2,3,3-trimethylindolenine, 2,3,3-trimethyl-4,5-benzo3H-indolenine, 3- and 4-picoline, lepidine, chinaldine and 9-methylacridine derivatives with the general formulae IIa or IIb or IIc
and where
X stands for an element of the group O, S, Se or the structural element N-alkyl or C(alkyl)2,
N stands for the numerical value 1, 2 or 3,
R1-R14 are equal or different and can be hydrogen, one or more alkyl, aryl, heteroaryl or heterocycloalipathic fragments, a hydroxy or alkoxy group, an alkylsubstituted or cyclical amine function and/or two fragments in ortho position to each other, for example R10 and R11, can together form another aromatic ring,
At least one of the substituents R1-R14 can be a solubilizing or ionizable or ionized substituent, like cyclodextrine, sugar, SO3xe2x88x92, PO32xe2x88x92, COOxe2x88x92, or NR3+, which determines the hydrophilic properties of these dyes; here it is possible that this substituent can be bound to the marker dye by means of a spacer group,
At least one of the substituents R1-R14 can stand for a reactive group which facilitates a covalent linking of the dye to the aforementioned carrier molecules, while this substituent can also be bound to the dye by means of a spacer group, and
R1 is a substituent which has a quarternary C-atom in alpha-position relative to the pyran ring. Examples for such substituents are t-butyl (xe2x80x94C(CH3)3) and adamantyl (xe2x80x94C10H15/tricyclo[3.3.1.13,7]decyl).
Subclaims 2 to 20 list specific embodiment forms and applications of the marker dyes.
These substituted derivatives of indol, heteroindol, pyridine, chinoline or acridine of the general formula I can be used as dyes for the optical marking of organic or inorganic microparticles, for example of proteins, nucleic acids, DNA, sugars, biological cells, lipids, drugs or organic or inorganic polymeric carrier substances.
Here, the marking of particles can be done by the formation of ionic interaction between the markers of general formula I and the substances to be marked.
The functional groups of these markers activated with regards to nucleophiles can couple covalently with an OH, NH2 or SH function, which therefore creates a system for the qualitative and quantitative determination of organic and inorganic substances, like said proteins, nucleic acids, DNA, sugars, biological cells, lipids, drugs or organic or inorganic polymers.
The coupling reaction can take place in an aqueous or mostly aqueous solution, preferably at room temperature. During this a conjugate with fluorescent properties is created.
By means of the preparation of non-symmetrical polymethines, which on the one hand have an easily derivatizable heterocycle of the type of the pyridine, chinoline, indol, heteroindol or acridine derivatives and on the other hand have a novel 6-ring heterocycle, in particular the following advantages are achieved:
Trimethines already absorb in the spectral range greater than 650 nm and have a significantly improved photochemical and thermal stability when compared with polymethines known so far in the art which have absorption maxima greater than 650 nm (penta- and heptamethines).
By means of molecular engineering, it is possible to control the position and intensity of the absorption and emission maxima at will and to adapt them to emission wavelengths of different excitation lasers, in particular NIR laser diodes.
The marker dyes can be produced by a relatively simple two-stage synthesis with which a variety of dyes with functionalities that differ, for example, with regards to the total charge of the dye and the number, specificity and reactivity of the activated group used for the immobilization can be provided in a manner that is specific to the respective application.
Compounds with the general formula I as well as systems derived from them (conjugates) can be used in optical, in particular fluorescence optical qualitative and quantitative determination methods for the diagnosis of cell properties, in biosensors (point-of-care measurements), exploration of the genome and in miniaturization technology. Typical applications lie in the fields of cytometry, cell sorting, fluorescence correlation spectroscopy (FCS), ultra-high throughput screening (UHTS), multicolor fluorescence in situ hybridization (FISH) and in microarrays (gene and protein chips).
Here, a microarray is a grid-like arrangement of molecules immobilized on at least one surface which can be used for the study of the interaction between receptors and ligands. A grid-like arrangement means more than two molecules which are different from each other and which are immobilized in different, predefined regions of known positions on a surface.
A receptor is a molecule which has an affinity to a given ligand. Receptors can be naturally occurring or artificially produced molecules.
Receptors can be used in their pure state or bound to other species. Receptors can be bound covalently or non-covalently either directly or via certain coupling mediators to a bonding partner.
Examples of receptors which can be detected by means of this invention include agonists and antagonists for cell membrane receptors, toxins and other poisonous substances, viral epitopes, hormones like opiates and steroids, hormone receptors, peptides, enzymes, enzyme substrates, active substances that act as co-factors, lectines, sugars, oligonucleotides, nucleic acids, oligosaccharides, cells, cell fragments, tissue fragments, proteins and antibodies, but they are not limited to the named substances.
A ligand is a molecule that is recognized by a particular receptor. Examples of ligands which can be detected by this invention include agonists and antagonists for cell membrane receptors, toxins and other poisonous substances, viral epitopes, hormones like opiates and steroids, hormone receptors, peptides, enzymes, enzyme substrates, active substances that act as co-factors, lectines, sugars, oligonucleotides, nucleic acids, oligosaccharides, cells, cell fragments, tissue fragments, proteins and antibodies, but they are not limited to the named substances.
The invention is subsequently to be illustrated in more detail by means of embodiment examples and the drawings.
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For many users such as hunters, outdoor enthusiasts and workers, it is common to use compact tools for ease of carrying. A pruning tool as an example, there are non-compact models as described in patent U.S. Pat. No. 50,840,975 granted on 4 Feb. 1992. Despite several improvements, the large size remains an annoying characteristic for many occasions as they are cumbersome. It therefore becomes inconvenient to carry this kind of tool despite its usefulness. Users will turn to compact tools like a folding saw, pocket knife or other smaller size sharp tools. This kind of saw is described in patent USD346937 granted 17 May 1994. The size of this saw makes it possible to place it in a pocket or a backpack. However, responding to the need of facilitating carrying, the reach of the tool is very short and it becomes impossible to use for working on vegetation located beyond a few feet of the user.
In the hunting context in particular, surrounding vegetation in shooting lanes often located up high and around a tree stand changes rapidly due to natural elements such as tree growth, wind and ice. Hunting site preparation may therefore become necessary just minutes prior to hunting from the stand and needs to be done quickly and with a silent approach. As hunting sites are often located deep into the forest and generally require many minutes of walk to get to, it is important to use a very compact and lightweight tool that can be carried into a backpack or inside a coat pocket. It therefore becomes obvious to use the saw with an extension fastener that can quickly be converted into a pruning tool to cut vegetation located more than two meters from the tree stand without having to carry extension poles to the site. To avoid injuries or incidents that may interfere with the activity, the tool with an extension fastener must be secure during transport and cutting. The extension fastener must be reliable, sturdy and quick to install. It is unthinkable to have a fastener requiring more than a few minutes to set up. We must also be able to use materials available on site and thereby reduce the amount of luggage and tools to carry. Since this product is an accessory, it must be inexpensive and simple to manufacture. The above described tool is a pruner and is used as an example since other tools could be equipped with such an extension fastener.
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It is known to provide privacy cubicles and partitions in public washrooms and change rooms. Conventional partition assemblies or systems usually have as their principal components all metal pillars or pilasters which are the vertical supports which function as the load carrying frame, as well as metal doors and divider panels. The cubicles and partitions are most frequently erected adjacent walls and room corners with the adjacent walls supporting various partition components as well as functioning as a side and/or the ends of the cubicles. The all metal construction of the partition components is disadvantageous in that to install conventional partition assemblies, it is necessary to premeasure and custom order the components of each partition assembly to precisely fit each separate installation. The necessity of premeasuring and ordering the components increases both the time and cost of installation of the partitions.
Conventional partition assemblies suffer a further disadvantage in that the metal components cannot readily be modified or trimmed to size once they have been manufactured. As such, miscalculations in measuring the installation site or changes in site dimensions with the finishing of wall tile, dry wall, countertops or the like may result in a preordered partition assembly which is too large or small to be installed at the intended site.
Conventional partition systems further incorporate a number of specialized parts for use in their erection. Typically different attaching members are used to attach partition divider panels to the pilasters, from those used to attach the divider panels to the wall. The requirement of increased numbers of specialized components makes the assembly of the divider systems more complex as well as increasing material costs.
Another difficulty with conventional divider systems exists in that the hinges which are used to attach the cubicle door frequently connect the door in such a manner that large gaps exist between the vertical edges of the door and the adjacent pilasters. These gaps deprive the user of the privacy which is intended by the partition system.
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1. Field of the Invention
This invention relates to floor coverings for public indoor walking areas and more particularly to means for pivotally connecting sections of floor coverings.
2. Description of the Prior Art
It is a common practice to provide floor coverings for general walking areas as in office buildings and other public buildings. Such floor coverings are generally adapted to be rolled up for cleaning purposes.
A prior art structure is disclosed in U.S. Letters Pat. No. 4,029,834 issued June 14, 1977, to G. F. Bartlett. Here what are described as rails form the portions of a mat, said portions being directly interconnected and end portions thereof are tapered to become flush with adjacent floor surface.
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The present disclosure relates to a client terminal, a server and a program.
In recent years, a digital camera has been widely used that stores and preserves a subject image in a recording medium as a digital image signal. A user directs the digital camera toward a subject, visually recognizes an image displayed on a viewfinder and presses the shutter button at a given timing.
Here, JP 2006-260338A proposes a digital camera capable of acquiring past and future images of a particular subject as a technology related to the above-mentioned camera. The digital camera described in JP 2006-260338A transmits, to a server, information, for example, a year, month, day and the position of the digital camera in the past indicated by the user. Then, the digital camera acquires, from the server, an image that corresponds to the indicated year, month and day. The digital camera then displays the image acquired from the sever in response to the timing at which the user presses the shutter button.
Meanwhile, JP 2010-128939A proposes a device that converts a viewpoint of an image captured by a camera mounted on a vehicle to generate a bird's eye image in which a three-dimensional object naturally looks as if it is viewed downward from substantially vertically above.
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The fish lures of this invention utilize some of the basic features disclosed in my prior U.S. Pat. No. 4,367,607 dated Jan. 11, 1983. Common to both disclosures are the jig heads having a retainer extending rearwardly to receive the forward end of a pliable plastic body element with the hook being passed through the middle portion of the body.
What is now desirable is to have a lure which will perform in the water very naturally and as a part of the environment. The lure should descend progressively more slowly as it levels out. The lure may be pulled through the water but will resist water forces on the lure tending to rotate it. It is important to be able to control the depth at which the lure moves through the water such that it will stay on top or at any desired level, including along the bottom. The lure should, due to its balance, assume a generally horizontal position as it moves through the water. The forward end of the pliable plastic body on the retainer should be protected against being inadvertently dislodged by contact with obstructions in the water. Since the plastic pliable bodies are interchangeably mounted on the retainer and the hook, location marking indicia should be provided on the forward end, top side, and bottom side of the body element to provide an indicator for positioning on the retainer and the hook.
Ballast should be used in combination with a hard plastic jig head to give the desired balance, orientation in the water, and rate of descent in the water. The shape of the jig head along its bottom and forward side should be such that it will assist in maintaining the desired lure orientation and level in the water.
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The present invention relates to illumination control of a turn signal for a vehicle, and more particularly, to a turn signal illumination controller that automatically cancels an illuminated turn signal indicator.
Turn signal indicators are arranged on an outer surface of a vehicle to notify others that the vehicle will turn right or left at an intersection or change lanes. A turn switch lever, which is arranged near the steering wheel, is tilted to the right (clockwise direction) to flash a right turn signal indicator, and tilted to the left (counterclockwise direction) to flash a left turn signal indicator.
The vehicle includes a turn signal illumination controller that controls the illumination and cancellation of the turn signal indicators in accordance with the operation of the turn switch lever. A widely used mechanical turn signal illumination controller switches a turn signal indicator from an illuminated state to a cancelled state by mechanically activating and deactivating a switch contact in cooperation with the movement of the turn switch lever. The operation of the mechanical turn signal illumination controller when the vehicle is turned to the right will now be described. The driver, for example, tilts the turn switch lever to the right from a neutral position and rotates the steering wheel to the right (clockwise rotation). When tilted to the right, the turn switch lever activates a micro switch. Further, a holding mechanism holds the turn switch lever at a right tilt position and keeps the micro switch activated. As long as the micro switch remains activated, the turn signal indicator continues to flash. Then, when the steering wheel is rotated back to the left (back rotation), the holding mechanism releases the turn switch lever in cooperation with the back rotation. This returns the turn switch lever to the neutral position from the right tilt position thereby deactivating the micro switch and cancelling the turn signal indicator.
Japanese Laid-Open Patent Publication No. 11-70833 discusses an auto-cancellation type turn signal illumination controller that automatically cancels a turn signal indicator without cooperating with the turn signal switch lever. The auto-cancellation type turn signal illumination controller includes a rotational angle sensor, which monitors the rotational angle of the steering wheel. When the steering wheel is rotated back toward its original position while the turn signal indicator is flashing, the turn signal illumination controller automatically cancels the turn signal indicator when the rotational angle sensor detects that the angle of the back rotation has reached a cancellation angle.
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In recent years, a variety of consumer boxes and cartons have been developed for packaging, shipping, storing, carrying, and dispensing a variety of products. An example of such packages and cartons is a carton for carrying fluent solid materials such as washing detergents, animals feeds and the like. A typical container for such products may often include a paperboard box with an openable lid or tear away dispenser and some type of attached or formed handle for carrying the carton or box.
A cardboard carton for granules including a lid having a locking recess for securing the lid is disclosed in U.S. Pat. No. 5,518,172. The contents of the carton are covered by a disposable sealing paper. The carton's handle is mounted to the side panels of the carton.
A carton for holding a detergent or other fluent solid material is disclosed in U.S. Pat. No. 5,566,878. The carton is made of paperboard and includes a handle on the side to facilitate pouring the contents. The handle configuration includes a false compartment that allows for deployment and use of the handle.
U.S. Pat. No. 4,768,703 discloses a carton with a hinged top panel for pouring the contents of the carton. The carton includes a membrane liner underneath the top panel for resealing the carton.
U.S. Pat. No. 4,986,420 discloses a package having a handle for housing granular or similar products. The handle is a substantially flat strap handle which has a barb member on each end. The handle is inserted into two opposing openings in the side walls of the package.
In those systems, a carton or container is reclosed by covering the open portion of the container with a liner, hinged lid or hinged flap. In those systems, the carton closures often do not close the carton sufficiently to prevent leakage or spillage of the contents of the carton. Additionally, most of those systems are carried by use of an externally mounted or formed handle which operates independent of the opening from which the contents of the carton or package are dispensed. Such handles typically protrude from or hang from the exterior surfaces of the container and may easily snag or catch on other boxes during shipment or storage. The handles may also interfere with top loading and top closure of the containers, and consequently, often require additional manufacturing steps in loading the containers. Also, the use of handles added to the container and produced from a different material or different piece of material increases the material and manufacturing costs of such containers.
There is a need in the art for a carton, formed from a foldable blank, that may be quickly and efficiently reclosed after opening and that prevents spillage or leakage of the contents of the carton. There is a further need in the art for a carton which may be end-loaded independent of the top closure/lid of the carton. There is a further need in the art for a carton having a carrying handle which is flush with the exterior surfaces of the carton to facilitate ease of stacking and shipment of the carton. There is further need in the art for a carton having a carrying handle and recloseable lid structure that minimizes contact of the user with the contents of the carton when carrying the carton.
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The invention relates to a system for identifying members of a viewing audience.
For a commercial television network, the cost of its advertising time depends critically on the popularity of its programs among the television viewing audience. Popularity, in this case, is typically measured in terms of the program's share of the total audience viewing television at the time the program airs. As a general rule of thumb, advertisers prefer to place their advertisements where they will reach the greatest number of people. Thus, there is a higher demand among commercial advertisers for advertising time slots along side more popular programs. Such time slots can also demand a higher price.
Because the economics of television advertising depends so critically on the tastes and preferences of the television audience, the television industry invests a substantial amount of time, effort and money in measuring those tastes and preferences. One preferred approach involves monitoring the actual viewing habits of a group of volunteer families which represent a cross-section of all people who watch television. Typically, the participants in such a study allow monitoring equipment to be placed in their homes. Whenever a participant watches a television program, the monitoring equipment records the time, the identity of the program and the identity of the members of the viewing audience. Many of these systems require active participation by the television viewer to obtain the monitoring information. That is, the viewer must in some way interact with the equipment to record his presence in the viewing audience. If the viewer forgets to record his presence the monitoring statistics will be incomplete. In general, the less manual intervention required by the television viewer, the more likely it is that the gathered statistics on viewing habits will be complete and error free.
Systems have been developed which automatically identify members of the viewing audience without requiring the viewer to enter any information. For example, U.S. Pat. No. 4,858,000 to Daozehng Lu, issued Aug. 15, 1989 describes such a system. In the system, a scanner using infrared detectors locates a member of the viewing audience, captures an image of the located member, extracts a pattern signature for the captured image and then compares the extracted pattern signature to a set of stored pattern image signatures to identify the audience member.
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1. Field of the Invention
This invention relates generally to microphone assembly in a system which needs to convert sound waves to electrical signals.
2. Description of the Related Art
A microphone is a basic and essential element in any audio systems. There are many types of microphones in use currently. Generally, they are classified in four categories as listed in FIG. 1. The first one is an omni-directional microphone 102. It has a uniform polar response, i.e., the sound waves from any directions can be accepted and an electrical signal is generated with the same gain. A second type of microphone, a dipole microphone 104, can respond to sound waves mainly from two opposite directions. Sound waves coming from other direction have a much smaller gain. The sound wave coming from a direction that is 90° to the axis of the microphone element is not accepted, i.e. the gain is null. A third type of microphone is a cardioid microphone 106, which can accept sound waves from one primary direction. The response gain decreases as the incident angle of a sound wave deviates from the primary direction. The response gain drop can be substantial when the incident angle is greater than a microphone is a hyper-cardioid microphone 108. Hyper cardioid microphone 108 is like a hybrid of a dipole microphone and a cardioid microphone. It has a primary direction and a secondary direction, which is the opposite of the primary direction. It can respond to sound waves in both the primary and the secondary directions, but its gain for the secondary direction is less than the gain for the primary direction.
An array of microphones may also be assembled to emulate the properties of the above four types of microphones in some applications. For example, non-directional microphones may be grouped together. A controller may process the signals in such a way so as to generate a signal that is highly directional, so this array of microphones acts as if it is a directional microphone. Another example is discussed in U.S. Pat. No. 5,715,319, where several directional microphones are arranged in a circular array. The resulting microphone array acts similarly to a non-directional or omni-directional microphone. In this application, a microphone element can refer to a generic single element microphone, or a multiple-element-array, which behaves similar to a single element microphone. For example, a unidirectional microphone can be a single cardioid microphone, or a microphone array that accepts sound waves from a primary direction and rejects sound waves from most other directions. The microphone elements within the microphone array may be non-directional, bi-polar or hyper-cardioid or some combination.
Any one of the four types of microphones identified above has various disadvantages in audio systems, especially in audio conferencing and video conferencing applications. For example, an omni-direction microphone, which gathers sound from all directions equally, can be used in recording studios where the noise and reverberation level can be made to low, but gives poor quality in audio or video conferencing applications, because of its inability to reject reverberation and noise in a typical untreated room environment. A cardioid microphone only accepts sound waves directed towards the microphone and rejects most sound waves coming from other directions. This type of microphone may provide a higher signal to noise ratio (SNR) and a better sound quality, but it can only cover a very small area in the conference room. Participants in an audio or video conference may have to take turns speaking to the microphone. In some conference room setups, several such microphones can be connected to the system simultaneously, so most participants of the conference have a microphone nearby available to speak into. But this type of arrangement complicates the conference room and makes the room cluttered.
Although it is generally accepted that one may have to hold a microphone while giving a lecture in a large auditorium, it is still unnatural and inconvenient. In a conference situation, it is even worse. In an actual meeting, meeting participants would like to watch people's expressions on their face and other body language as they speak.
There are prior art devices that avoid many of the limitations of the microphone elements. For example, a Polycom SoundStation VTX-1000 speakerphone from the assignee of the current invention uses three microphone elements to provide better room coverage, SNR and frequency response. This speakerphone fulfills many requirements in a conference setting such that it appears on most conference room tables.
It is more desirable to eliminate the inconvenient microphones, or at least to keep them out of sight during a conversation and minimize their interference. It is desirable to have a microphone system that can provide coverage of the entire conference room, while at the same time keeping the sound quality high and maximizing the signal to noise ratio. It is desirable to have a microphone system that can provide other high quality sound processing.
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The invention claimed herein relates generally to loading dock bumper devices used to protect loading docks and/or vehicles from damage resulting during the loading/unloading process and, more particularly, to a vertically movable loading dock bumper device.
Loading dock bumper devices are well known in the art. They are used to protect loading docks and vehicles from damage resulting from the vehicles contacting the loading dock during loading and/or unloading activity. Damage to the loading dock and/or the vehicle would otherwise occur because a typical loading/unloading activity is initiated by the vehicle backing towards the loading dock until the rear of the vehicle is very close to the loading dock. Because too great a gap between the vehicle and the loading dock would make loading/unloading difficult, drivers typically err on the side of bringing the vehicle too close to the loading dock, often resulting in contact therewith. Having a loading dock bumper disposed between the vehicle and the loading dock allows the vehicle to back towards the loading dock without fear of contact, as the dock bumper disperses the force of a low speed contact without damage to either the vehicle or the loading dock.
Most loading dock bumper devices are immovably fixed to loading docks. Swessel, et al., U.S. Pat. No. 4,744,121 (May 17, 1988), discloses such immovably fixed dock bumpers. Other configurations use dock bumpers which are affixed to moveable portions of the loading dock, but in such configurations the bumper is essentially immovable once the loading dock has been correctly positioned for the specific vehicle and loading/unloading begins. Hahn, U.S. Pat. No. 6,360,394 (Mar. 26, 2002) discloses dock bumpers fixedly attached to a movable dock leveler, and van de Wiel, et al., U.S. Pat. No. 6,497,076 (Dec. 24, 2002) discloses a bumper affixed to a device which moves between an operative position and a stored position. However, in both these devices once the dock bumper is positioned for the loading/unloading activity, it remains in that position and effectively becomes an immovable bumper for the duration of the activity.
The disadvantage of such devices is evident from observations of their use with vehicles employing air suspension technology. The cargo box or trailer of a vehicle so equipped moves vertically on its air suspension mechanism to accommodate different cargo weights. A lighter load causes the cargo box or trailer to ride higher, and a heavier load causes it to ride lower. During the loading/unloading process, however, the weight of the cargo necessarily changes. Moreover, machines that may be used in the loading/unloading process, such as forklifts, can substantially (if only temporarily) alter the weight of the vehicle when they are driven onto and off of the vehicle. As a result, during the loading/unloading process the vehicle is often caused to move vertically, often in both directions and often with many movements, corresponding to the changing weight within the cargo box or trailer.
When a vehicle is backed against a dock bumper, lateral forces continue to be exerted against the bumper by the vehicle as long as contact continues. When a vehicle having an air suspension mechanism moves vertically during the loading/unloading process, as described above, the lateral forces against the bumper (or even friction between the rear of the vehicle and the bumper) may be sufficient to overcome any slipping between the rear of the vehicle and the bumper, the bumper is physically moved along with the vehicle. When such movements exceed the deforming properties of the bumper, the bumper is either ripped, torn, or otherwise damaged, or detached from the loading dock, or both.
A dock bumper device which permits the dock bumper to move in concert with the rear of the vehicle during the loading/unloading process significantly reduces the damage that would occur to the dock bumper and/or the loading dock, as described above. As such, replacement, repair, and maintenance of the dock bumper is greatly reduced, at significant cost and time savings.
Examples of vertically movable dock bumpers are disclosed in the following references:
Drawing xe2x80x9cAdjustable Bottom Pad (692-0029)xe2x80x9d; dated Oct. 17, 1985 (showing a vertically adjustable pad mounted to the dock face);
Spec Sheet xe2x80x9cLoading Systems Mobile Dock Bumper RB 250Mxe2x80x9d; dated circa 1993 (showing a vertically-adjustable spring-loaded dock bumper); and
Drawing xe2x80x9cHohenbeweglicher Anfahrpuffer 5146.0102xe2x80x9d; dated November 1995 (showing a vertically-adjustable, spring-loaded dock bumper).
While each of these references discloses a vertically movable dock bumper, the devices disclosed therein are of complicated and inferior design. As such, the cost of manufacture and/or installation of these devices would be high, as would be the likelihood of failure during operation. The invention claimed herein seeks to address these design flaws with its simple yet rugged design and utilization of a movement mechanism which reduces the potential for lateral binding present in the devices disclosed in the prior art, thereby resulting in a reduction of the deficiencies inherent in the prior art devices.
In one aspect, the invention is directed to a loading dock bumper device adapted to allow for the vertical movement of a bumper. This aspect may include one or more of the following features:
a mount component, a bumper component, and a slide component, whereby the mount component is suitably adapted to fixedly attach to a loading dock, the bumper component is suitably adapted to accommodate a bumper, and the slide component is suitably adapted to connect the bumper component to the mount component in a manner permitting the bumper component to move along the mount component in a vertical direction in concert with the vertical movement of a vehicle; the mount component may be constructed of channel iron having a substantially flat back panel and two lateral flanges, a top plate constructed of sheet steel or bar stock, and an attachment plate constructed of angle iron; the bumper component may be constructed of channel iron having a substantially flat front panel and two flanges oriented along the top and bottom, with the bumper component suitably adapted to fit within the flanges of the mounting component and against the inner surface thereof, and suitably adapted to carry a bumper on its outer surface; and the slide component may be constructed of a pair of steel rods with a pair of springs disposed thereon, with the pair of rods disposed through apertures formed into the mount component and the bumper component such that the rods are fixedly attached to the mount component and retain the bumper component within the mount component, and the springs support the bumper component and facilitate its movement in a vertical direction.
Other features and advantages of the invention are described below.
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A multi-carrier communication system, such as a Discrete Multiple-Tone (DMT) system in the various types of Digital Subscriber Line (e.g., ADSL and VDSL) systems, carries information from a transmitter to a receiver over a number of sub-channels or tones. DMT is a two line-modulation technique used for VDSL. A DMT communication system divides signals into multiple separate channels or tones. Each tone acts as a separate communication channel to carry information between a local transmitter-receiver device and a remote transmitter-receiver device. Each tone is a group of one or more frequencies defined by a center frequency and a set bandwidth.
DMT communication systems use a modulation method in which the available bandwidth of a communication channel, such as twisted-pair copper media, is divided into these numerous tones. The term communication channel is understood to refer generally to a physical transmission medium, including copper, optical fiber, and so forth, as well as other transmission mediums, including radio frequency (RF) and other physical or non-physical communication signal paths.
There are various types of interference and noise sources in a multi-carrier communication system, such as the DMT system. Interference and noise may corrupt the data-bearing signal on a tone as the signal travels through the communication channel and is decoded at the receiver. The transmitted data-bearing signal may further be decoded erroneously by the receiver because of this signal corruption. The number of data bits or the amount of information that a tone carries may vary from tone to tone and depends on the relative power of the data-bearing signal compared to the power of the corrupting signal on that particular tone. Thus, a measure of the quality of signal carried by a tone is the ratio of the received signal strength (power) over the noise strength in the frequency range of operation, or the Signal to Noise Ratio (SNR). High SNR results in high signal quality being carried by a tone. Another measure of signal quality is bit error rate (BER) for a given tone.
In order to account for potential interference on the transmission line and to guarantee a reliable communication between the transmitter and receiver, each tone is typically designed to carry a limited number of data bits per unit time based on the tone's SNR using a bit-loading algorithm. The number of bits that a specific tone may carry decreases as the relative strength of the corrupting signal increases, that is when the SNR is low or the BER is high. Thus, the SNR of a tone may be used to determine how much data should be transmitted by the tone.
It is often assumed that the corrupting signal is an additive random source with Gaussian distribution and white spectrum. With this assumption, the number of data bits that each tone can carry relates directly to the SNR. However, this assumption may not be true in many practical cases and there are various sources of interference that do not have a white, Gaussian distribution. Impulse noise is one such noise source. Bit-loading algorithms, which are methods to determine the number of bits per tone, are usually designed based on the assumption of additive, white, Gaussian noise. With such algorithms, the effects of impulse noise are underestimated resulting in an excessive rate of error.
Further, channel estimation procedures can be designed to optimize performance in the presence of stationary impairments such as additive, white, Gaussian noise, but are often poor at estimating non-stationary or cyclo-stationary impairments, such as impulse noise. Consequently, DSL modem training procedures are typically well suited to optimizing performance in the presence of additive, white, Gaussian noise, but leave the modem receivers relatively defenseless to impulse noise.
Impulse Noise can be a difficult impairment for DSL modems. Impulse noise with duration of tens of microseconds can cause errors in all the used sub-channels at the receiver. Further, because a DMT system programs the impulse noise protection for entire DMT frames, not just for the length of impulse found in the network, latency is introduced in the system.
Typically, impulse noise is mitigated by a combination of two methods: forward error correction (FEC) with interleaving and reducing data rate for increased noise margin. One mitigation strategy compatible with current ADSL2 and VDSL1 procedures is to operate the receiver with sufficient noise margin (including Reed-Solomon coding and interleaving) to maintain the error rate within acceptable limits. Unfortunately, this means that 90-98% of frames are typically running with excess margin to ensure the integrity of data in 2-10% of the frames directly impacted by impulse noise. Further, this method generally does not work for low-latency applications, and it requires a very large interleaver depth, which increases system memory requirements.
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Voice Over Internet Protocol (“VoIP”) networks have significantly reduced the barrier of entry for using mass telephone calling applications such as auto-dialers, and these applications are increasingly available to users with bad intentions. Such mass telephone calling applications not only allows users to generate vast amounts of network traffic, but provide the flexibility to fake the identity of the traffic they are generating. This, coupled with the overall leniency and lack of controls of some VoIP service providers, has resulted in the increasing occurrence of identity misrepresentation and counterfeiting for fraudulent purposes.
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The present invention relates generally to electronic cryptography technology, and in particular to protecting a security device against side-channel attacks by using multiplicative masking using simultaneous exponentiation techniques.
Electronic communication and commerce can be powerful yet dangerous tools. With the wide-spread availability of network technology, such as the Internet, there is an ever increasing use of online tools for communication and commerce. Every year more users find it easier or quicker to conduct important transactions, whether in the form of correspondence or commerce, using computers and computer networks. However, there is always the risk that the security of electronic transactions is compromised through interception by third parties who do not have the right to partake in the transactions. When malicious third parties obtain access to otherwise private transactions and data there is risk of economic loss, privacy loss, and even loss of physical safety. Cryptography is one mechanism employed to avoid intrusion into the privacy of electronic transactions and data.
Cryptography is a technology for hiding a message in the presence of third parties using mathematical techniques in which a message is encrypted in such a way that it can only be decrypted using a secret key that should only be known by the recipient and/or sender of a message.
Cryptographic algorithms have inputs and outputs. In the case of encryption, the input is a message that is to be protected in plaintext. The plaintext message is manipulated by the cryptographic algorithm to produce a ciphertext, the output. To produce the ciphertext the cryptographic algorithm performs certain mathematical operations that include the use of a secret key. The key may be a shared secret, e.g., between a sender and recipient, or may be a private key held by the recipient.
One frequently used cryptographic technique is the RSA algorithm named for its inventors Rivest, Shamir, and Adelman. To obtain a highly secure ciphertext, the RSA algorithm relies on the difficulty of factoring large integers. A user creates a public key by randomly selecting two large similar-sized prime numbers and multiplies these two numbers together. The result is the public key of the user which the user may publish thereby enabling other entities to encrypt messages for the user. While the public key is public and anyone can encrypt a message with its use, the encrypted message can only be decrypted using the corresponding private key which, in effect, consists of the two prime numbers that were used to generate the public key. It is therefore critical to the security provided by the RSA algorithm that the private keys are kept secret and cannot be discerned by a third party attempting to subvert the secrecy of RSA-encrypted messages.
While the details of the RSA algorithm are beyond this document, for discussion purposes herein the algorithm may be reduced to two complimentary calculations for encryption of a message M into a ciphertext C and the decryption of the ciphertext C back into the message M. The public key is computed from two large prime numbers p and q. From p and q a number n=pq is computed; n is the modulus for both private and public keys. Furthermore e, the public key exponent is computed from p and q, as follows:
Choose e such that: 1<e<φ(n) and the greatest common divisor of (e, φ(n))=1, i.e., e and φ(n) are coprime, wherein, n=pq and φ(n) is Euler's Totient function.
Thus, the public key consists of the pair of integers (n, e). The corresponding private key consists of the pair of integers (n, d) where d≡e−1 (mod φ(n)) where φ(n) is Euler's Totient function.
A message M is encrypted using the public key (n, e) into ciphertext C by:C=Me mod n
The message M is recovered and decrypted from C using the corresponding private key (n,d) by:M=Cd(mod n)
RSA may also be used to cryptographically sign a message M into a signed message S, i.e.,S=Md(mod n)
Usually these computations are not performed directly as the exponentiations on large integers are expensive computations. A more efficient computation, which involves exponentiation of much smaller integers, uses the Chinese Remainder Theorem. Without going into details, the Chinese Remainder Theorem approach includes the modular exponentiations:Sp=Mpdp mod pSq=Mqdp mod q Wherein dp=d mod (p−1) and dq=d mod (q−1), and Mp=M mod p and Mq=M mod q
The RSA-CRT signature computation is composed of 3 main steps: Computing Sp (about 45% of the computation) Computing Sq (about 45% of the computation) Recombining S from Sp and Sq (about 10% of the computation)
Side-channel attacks make use of the program timing, power consumption and/or the electronic emanation of a device that performs a cryptographic computation. The behavior of the device (timing, power consumption and electronic emanation) varies and depends directly on the program and on the data manipulated in the cryptographic algorithm. An attacker could take advantage of these variations to infer sensitive data leading to the recovery of a private key.
Fault attacks derive their name from the practice of creating a fault during the computation and exploiting the result produced by that fault to deduce the secret key. Generally, injecting a fault requires a prior step that consists of determining the most likely successful moment for the fault injection. This prior step is usually done by reverse engineering the program through studying the power or the electronic emanation trace. RSA-CRT is particularly vulnerable to fault attacks because disturbing either the computation of Sp only or Sq only can allow the intruder to deduce the private key, whichever fault effect is caused. Moreover, the set up for inducing a fault during either Sp or Sq computation is relatively easy to do because these two sensitive steps are usually easily identifiable on a power trace. Since Sp and Sq occupy a large portion of the process, roughly 45% each of the total signature, there is ample time to disturb either computation. Thus, a fault disturbing the computation of either Sp or Sq could allow the unauthorized recovery of the private key prime factors.
One mechanism used to defend against fault attacks is to perform the signature operation twice to ensure that no fault has been introduced during the computation. Doing such operations twice would be a costly countermeasure.
Other prior art techniques include Shamir (Shamir, U.S. Pat. No. 5,991,414, Method and apparatus for protecting public key schemes from timing and fault attacks), Aumuller (Aumuller et al, Concrete results and practical countermeasures, Cryptographic Hardware and Embedded Systems——CHES 2002: 4th International Workshop, Volume 4), Giraud (Giraud, C., An RSA implementation resistant to fault attacks and to simple power analysis, IEEE Transactions on Computers (Volume: 55, Issue: 9), September 2006), and Vigilant (Cryptographic Hardware and Embedded Systems—CHES 2008, Lecture Notes in Computer Science Volume 5154, 2008, pp 130-145).
These prior art techniques may be divided in two types: The Shamir technique, from which the Aumuller and Vigilant techniques are derived, consists of multiplying the modulus by a small random number before the exponentiation. The exponentiation is performed modulo this new number and some consistency checks can be performed modulo the small random number after the exponentiation. A global consistency check is performed after the recombination. If the global consistency check fails, a fault attack may have been detected. Giraud's technique consists of using the Montgomery ladder exponentiation algorithm that outputs (X(y−1) mod Z, Xy mod Z) when computing Xy mod Z.
Common to these prior techniques is that they all detect the fault with some probability, except Giraud's one. But Giraud's technique has the drawback to require a large amount of RAM memory for its implementation. Moreover these techniques keep a three-step structure: computation of Sp, computation of Sq, and recombination. Having three steps provides an attacker multiple opportunities to set up a fault attack.
From the foregoing it will be apparent that there is still a need for an improved technology to provide a secure mechanism that is computationally efficient, that does not require excessively large registers or other storage, and in which a portable security device—e.g., a smart card connected to a host computer—can provide the capability of providing cryptographic services that are protected from fault attacks.
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Thermal control systems have been devised to regulate the temperature of waste heat generating equipment. These systems typically dissipate heat from the equipment by mounting the equipment conductively against an external surface such as the exterior wall of a container, spacecraft or airplane and, thereby, allowing the external surface to radiate heat into the surrounding environment. Other designs for control systems allow the equipment to radiate waste heat into the interior of the vehicle and then use an external radiating surface such as the outer walls or discrete radiators mounted on the vehicle's exterior to cool the interior. In other systems thermal switches or heat pipes conduct waste heat from the interior of the vehicle to discrete, external radiators which discharge the waste heat directly into the surrounding environment. Heat transfer through the heat pipes and radiators has, in some systems, been made variable by means of variable conductance heat pipes, thermal switches or thermocouple actuators for positioning louvers to cover the radiating surfaces.
With the exception of those designs having the heat generating equipment mounted directly against an external radiating surface, previously available thermal control systems have had relatively low thermal efficiencies due to the intrinsically low transfer efficiencies of non-conductive intermediate links between the equipment and the radiating surfaces. These systems have performed satisfactorily despite their thermal inefficiencies because the heat generating equipment has usually been operated at temperatures above 30.degree. C. over wide ranges of tolerance and the quantity of heat generated has been relatively small in comparison to the areas of the spacecraft available for use as external radiating surfaces. Their thermal inefficiencies, however, makes these systems unsuitable for reliably controlling the temperature of equipment operated below 30.degree. C. Additionally, they are unsuitable for maintaining precise equipment temperature in the presence of such external causes of thermal variation as earth shine, albedo and diurnal ambience. Furthermore, these systems depend upon large radiating surface areas and usually require deployable radiator panels that render them unsuitable for compact spacecraft applications.
Several features of spacecraft, particularly their low-temperature, gravity-free environment and their accessibility to a constant, albeit limited, source of energy in the form of solar radiation have prompted proposals for using earth-orbiting spacecraft as plants for carrying manufacturing equipment and processes such as a continuous flow electrophoresis system for manufacturing blood plasma. These proposals include deployment of spacecraft containing process plants via a Shuttle-type cargo vehicle for multi-year operations with periodic, interim visits to the orbiting spacecraft to remove finished products and deliver additional raw materials. Economy of scale requires, however, that to achieve economic viability, such plants must be much larger than previously deployed experimental and communications spacecraft. Spacecraft containing exothermic industrial processes will, accordingly, require thermal control systems having a capacity approximately proportional to the cubic power of the waste heat removing capacity of current spacecraft systems because the quantity of waste heat generated is proportional to the volume of the plane. Such systems must be able to continuously radiate between several hundred to a few thousand watts of waste heat. The multi-layer lifetimes planned for these plants and the current lack of cooling system machinery such as pumps and compressors, able to provide continuous, maintenance-free operation over such lifetimes necessitates a passive system having no moving parts while conservation of the available power obtained from solar energy for more profitable use in the industrial process requires that the system consume little or no power. The size of the cargo bay capacity in Shuttle-type vehicles limits the overall size of industrial process spacecraft, thereby providing an incentive for maximizing the volume available to the industrial process by miniziming that required by auxiliary plant components such as the thermal control system. Ease of handling during deployment and interim vists, a need to provide a dynamically stable spacecraft to avoid interruption of an industrial process with sudden G-forces, and maintenance of an alignment between the spacecraft's solar panels and the sun, further requires that the thermal control system be relatively compact and have its mass symmetrically distributed so as to not significantly effect stability of the spacecraft. Moreover, the presence of solar panels means that the heat rejection system cannot use deployable radiator panels that might shade the solar panels and thereby interrupt the flow of solar energy to the process.
There has not been yet developed a controllable system without moving parts for removing variable quantities of heat from a continuously flowing, closed process loop. Such a system would be very useful in an airborne or an outer space environment where corrective maintenance is not available. The inefficiencies in the thermal conduction provided and the relatively large exterior radiating surfaces required by currently available thermal control system designs means that these designs are unsuitable for use with proposed air or spaceborne processes. Moreover, the construction of these thermal control systems as integral parts of a spacecraft renders them suitable for use in space as a compact, quickly detachable part of a spacecraft. Consequently, the large size, periodic maintenance requirements, difficulties of disassembly, and thermal conduction inefficiencies of state of the art thermal control systems means that both a process plant and its thermal control system must be retrieved from space together, a requirement which unnecessarily restricts the size of the plant and, thereby, limits its profitability.
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1. Field of the Invention
The invention relates generally to the field of communication systems for vehicles such as automobiles and trucks, and more particularly, to communicatively coupling devices within the vehicle.
2. Description of the Related Art
Microprocessor technology has greatly improved the efficiency, reliability and safety of the automobile. Microprocessor devices have enabled airbags, anti-lock brakes, traction control, adaptive suspension and power train control just to name a few of the areas where processing technology has literally transformed the automobile. These systems, first provided by manufacturers only on the most expensive luxury and performance automobiles, are now common and even standard equipment on the most affordable economy models. Soon, control-by-wire applications will become equally commonplace. For example, throttle-by-wire has been successfully implemented on a number of vehicle platforms. Steer-by-wire and brake-by-wire applications are not far behind. Alternative fuel vehicles, including fuel cell vehicles, electric and hybrid vehicles will require still more sophisticated control applications, and hence still more processing capability.
The automobile is simultaneously being enhanced by information technology. Satellite navigation systems, voice and data communications, and vehicle telemetry systems inform the driver, entertain the passengers and monitor vehicle performance. These systems can provide driving directions, identify points of interest along the driver's route, remotely diagnose and/or predict vehicle problems, unlock the doors, disable the vehicle if stolen or summon emergency personnel in the event of an accident.
The growing amount and level of sophistication of vehicle oriented information technology presents the challenge to the automotive engineer to implement and integrate these technologies with existing and emerging vehicle systems in an efficient manner. Current design philosophy centers on the incorporation of one or more vehicle communication bus structures for interconnecting the various control elements, sensors, actuators and the like within the vehicle. The design of these bus structures is often driven by compliance with governmental regulations such as second-generation on-board diagnostics (OBD-II) and federal motor vehicle safety standards (FMVSS). These structures offer limited ability to adapt new technology to the vehicle. Moreover, given the typical four-year design cycle and ten-year life cycle of an automobile, the technology within a vehicle may become significantly obsolete even before the vehicle is brought to market, and the bus architecture leaves the owner little ability to adapt new technology to the vehicle. Notwithstanding these limitations, the bus architecture offers a generally reliable, relatively fast platform for linking electronic devices and systems within the vehicle.
To link vehicle system technologies with vehicle information technologies, there has been proposed to incorporate a network architecture within the vehicle. For example, published Patent Cooperation Treaty (PCT) application number WO 00/77620 A2 describes an architecture based on the Ethernet wherein devices within the vehicle are coupled to the network. This publication describes a network including a cable backbone to which the devices are coupled and a network utility for controlling communications between the devices over the network. Important to note is that the proposed network does not integrate the vehicle systems, but instead is adapted to provide a platform for adding information technologies, such as pagers, personal digital assistants, navigations, etc. technologies to the vehicle. The power train, suspension, braking and airbag systems, as examples, utilize a vehicle bus for data communications, and these systems operate autonomously of the network described in the publication. A bridge or gateway is provide to couple the vehicle bus to the network as a device or client allowing data sharing between the bus and the network, but the data communication needs of the vehicle systems are not serviced by the network. A reason that these systems are designed to operate autonomously of the described network is that they have time critical, system critical data requirements that cannot be met by the network structure described. Additionally, the network described in the publication suffers from numerous single points of failure, such as if the cable backbone is disrupted or the network utility fails.
Thus there is a need for an architecture for automotive electronic systems that facilitates the efficient, reliable integration of in-vehicle electronic technologies and plug-and-play upgradeability.
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(a) Field
The invention relates to a thin film transistor array panel.
(b) Description of the Related Art
Liquid crystal displays (“LCDs”) are one of the most widely used flat panel displays. LCDs display images by applying voltages to field generating electrodes to generate an electric field in an LC layer that determines orientations of LC molecules therein to adjust polarization of incident light.
In general, the LCD includes a display panel which includes two substrates each including a field generating electrode and a liquid crystal layer interposed therebetween, and pixels or pixel areas are defined thereon. A pixel electrode among the field generating electrodes is arranged in a matrix on a substrate and is connected to a switching element such as a thin film transistor (“TFT”), thereby sequentially receiving a data voltage for one row of pixels or pixel areas.
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1. Technical Field
The present invention relates generally to a direction control assembly for an aerospace vehicle and, more particularly, to a flap assembly at the forebody of a reusable launch vehicle for rotating and stabilizing the vehicle during entry and pre-landing maneuvers.
2. Discussion
Reusable launch vehicles used to deploy satellites in a predetermined orbit about the earth include single stage to orbit ("SSTO") vehicles that are designed to perform their intended operation and return to earth without jettisoning any portions of the vehicle. Accordingly, SSTO vehicles do not include discardable booster rockets or fuel tanks. Rather, the fuel supply elements of SSTO vehicles are retained throughout the flight thereby increasing the need to minimize fuel consumption in order to decrease the unusable weight carried into orbit. The present invention addresses these concerns by providing a vehicle rotation and control mechanism that reduces propellant acquisition subsystems and the propellant required to properly position the vehicle for landing.
Vertically landing SSTO vehicles commonly include a conically shaped airframe configured for stable flight in a nose-forward orientation. However, since the vehicle is vertically landed in a rearward or tail-first orientation a rotation of the vehicle during the landing sequence is required. Currently, SSTO vehicles of this class perform the rotation maneuver through the use of engine power. More specifically, the maneuver includes starting several of the main engines, retracting entry flaps so that the vehicle pitches up to initiate rotation, and selectively throttling up the engines to arrest rotation and place the vehicle into the desired base-first orientation. In order to minimize the quantity of propellant consumed by the engines between the rotation and touch down phases of the landing procedure, this rotation maneuver is generally conducted at a relatively low altitude. While this procedure is viable, a considerable amount of propellant is used during the starting and operation of the engines and the propellant feed system becomes heavy and complex. Further, the relatively low altitude compresses landing functions into a shorter timeline.
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{
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1. Field of the Invention
The present invention relates to a relay device and a server which relays a data packet, and particularly to a relay device capable of performing dynamic port forward setting and a setting method thereof.
2. Description of the Related Art
In order to always perform a connection to a wide area network such as an internet, the spread of a CATV has become serious and the spread of a broad band router has also become remarkable. However, the absolute number of global IP addresses (hereinafter referred to as external IP addresses) is insufficient in an existing IP protocol IPv4. For this reason, a countermeasure is taken against the shortage of the external IP address by using an NAT (Network Address Translation) function and a port forwarding function (a static IP masquerade).
The NAT function serves to convert a local IP address (an internal IP address which will be hereinafter referred to as an IP address) into an external IP address on the WAN side of a router when access is given from a CP on an LAN side to an internet. Consequently, the CP on the LAN side can give access to the internet by using the external IP address of the router.
On the other hand, the port forwarding function serves to transfer a packet directed to the external IP address and external port number of the router to a corresponding internal IP address and port number by using a preset port mapping table. Consequently, access can be given from the internet to a specific CP on the LAN side. More specifically, a conversion table (a port mapping table) for a port number and an IP address is first preset to the router, and the external IP address and external port number of the router is designated when access is given from the internet. The router accepting the access converts the external IP address into the IP address in accordance with the preset port mapping table. By the conversion, access can be given to the CP in the LAN having the IP address.
By the port forwarding function and the NAT function, a conventional router relieves the exhaustion of the external IP address and connects a plurality of user CPs in a LAN to an internet. However, a user is to obtain the port number of the CP and to manually perform setting and changes.
However, the manual setting is troublesome, and furthermore, is insufficient in respect of the practical utilization of a port. For this reason, there was created a standard for dynamically performing port forward setting (port mapping) by a UPnP forum (see a UPnP standard, internet <URL: http://www.upnp.org/standardizeddcps/default.asp>). In the setting of the standard, an external port is designated from a terminal to be a follower to a router to give a request for port forward setting and the router performs a registration if possible and the terminal sends a request again if impossible, and this is repeated until a determination is performed.
Specific description will be given to dynamic port forward setting to be executed based on a UPnP standard to be performed when an apparatus (a Control Point which will be hereinafter referred to as a CP) such as a computer device to a router to which an external IP address “60. 50. 40. 3” is assigned.
First of all, when the CP is connected to the router, it transmits a DHCP discovery packet and a DHCP server assigns an unused IP address “192. 168. 0. 1” to the CP. Subsequently, the CP transmits a router discovery packet and the router responds thereto. Upon receipt of the response, the CP transmits a port forward setting request specifying an external port number so that the router assigns the external port number to a port mapping table and responds thereto. The IP address and the port number of a CP to be a request source and the external port number of the router are designated for the port forward setting request. For example, when a port forward setting request specifying the IP address “192. 168. 0. 1” of the CP, a port number “80” of the CP and a router external port number “8081” is given from the CP, a port mapping table relating the IP address “192. 168. 0. 1” and the port number “80” of the CP to the router external port number “8081” is generated and stored by the router.
When the port mapping table is thus generated automatically and access is then given with “http//:60. 50. 40. 3 : 8081” from the client terminal of an external IP address “232. 0. 0. 2” connected to an internet, the router performs port forwarding over the packet to “http//:192. 168. 0. 1 : 80” in accordance with the port mapping table generated dynamically.
As described above, the dynamic port forwarding setting function of the UPnP standard of the conventional router sends a request for the port forward setting from the CP to be the follower to the router, and the router performs a registration if possible, and the terminal sends a request again if impossible. This operation is repeated until a determination is performed.
However, the CP can set the port forward to only the router in a subnet. In the case in which another router is required for the connection to the internet, it does not know the presence of the CP. After all, it is impossible to ensure a router to which access is given from the WAN side.
FIG. 26 is an explanatory view in which a conventional router having a UPnP standard is provided between an internet and a CP in two stages.
In FIG. 26, an upper router 102 has a WAN side I/F portion (not shown) to be connected to a WAN (an internet 101) for a communication through TCP/IP and a LAN side I/F portion (not shown) connectable to a LAN, and can dynamically perform port forward setting in accordance with a UPnP standard. Similarly, a lower router 103 has the WAN side I/F portion (which is connected to the LAN side I/F portion of the upper router 102) to be connected to the WAN for the communication through the TCP/IP and the LAN side I/F portion connectable to the LAN, and can dynamically perform the port forward setting in accordance with the UPnP standard.
The LAN side I/F portion of the lower router 103 is connected to a CP 104 such as a computer device. Accordingly, the internet 101 is connected to the CP 104 through a router having two stages which is constituted by the upper router 102 and the lower router 103.
A computer terminal 105 mounting a browser function is connected to the internet 101.
In case of a conventional UPnP standard compatible router connected in two stages, there is the drawback in routing. More specifically, the CP 104 connected to the router 103 can retrieve only the router 103 present on the same network. Accordingly, the CP 104 can perform the port forward setting for only the router 103 and cannot perform the port forward setting for the upper router 102. For the same reason, the CP 104 can acquire the outer IP address of the router 103 and cannot know the outer IP address of the router 102. When the computer 105 provided on the internet is to be connected to a web server operated on the CP 104 connected to the LAN side of the router 103, accordingly, the connection cannot be performed because the port of the upper router 102 is not opened. In the case in which a P2P communication is to be performed, moreover, the CP 104 can transfer the IP address of the CP 104 or the IP address of the router 103 to a communication partner. These two addresses are private IP addresses. For this reason, it is impossible to establish a communication session from the communication partner.
As the same kind of problems, conventionally, some relay devices for relaying a communication packet between a first network and a second network, for example, a router are caused to have a DHCP function and dynamically assign an IP address to a terminal to be a follower (the second network side).
In such relay devices, a user is to set an address range to be assigned to the terminal to be the follower by a manual operation, and a heavy burden is imposed on a user having no expertise.
Therefore, it can be proposed that an address range to be dynamically assigned to the relay device is preset. However, there is a possibility that the first network and the set address range might be coincident or overlap with each other. In some cases in which the address ranges of the first network and the second network are coincident or overlap with each other, access cannot be given from the terminal to be the follower to the first network. For example, in the case in which the first network and the second network have the same address “192. 168. 2. 1” respectively, a transmission to the second network side is simply performed and a transfer to the first network is not performed even if access is to be given from the second network side to a first network side apparatus “192. 168. 2. 1”.
By assigning a non-overlapping address range is assigned from an upper relay device on the first network side, moreover, it is possible to avoid such a problem (see JP-A-2002-290437, for example). In the case in which there is no upper relay device for assigning an address range for a DHCP to the relay device, the problem cannot be solved.
As described above, in the case in which the addresses overlap with each other at the first network side and the second network side, there is a problem in that the routing of a packet between the networks cannot function well.
Finally, it is necessary to perform transfer setting such as port forward (a static IP masquerade function) for a router device connected between a wide area network and a local network in order to give access from the wide area network to a server connected into the local network. In order to give access from the wide area network side to a server in the local network, accordingly, it is necessary to input a port number to be transferred to a server in addition to the IP address or host name of a router.
Therefore, the applicant has proposed a router capable of dynamically generating a web page linked to a server such as a camera server and giving access from a client terminal to the router, thereby acquiring information from the server as described in JP-A-2003-198586.
As described above, the router proposed by the applicant can dynamically generate the web page linked to the server such as the camera server and can give access from the client terminal to the router, thereby acquiring the information from the server. However, there is not considered a countermeasure to be taken against the case in which a relay device for rewriting an IP address or a port number to transfer a packet is present between a client and a server.
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In electrophotography, an electrophotographic substrate containing a photoconductive insulating layer on a conductive layer is imaged by first uniformly electrostatically charging a surface of the substrate. The substrate is then exposed to a pattern of activating electromagnetic radiation, such as, for example, light. The electromagnetic radiation selectively dissipates charge in illuminated areas of the photoconductive insulating layer while leaving behind an electrostatic latent image in non-illuminated areas of the photoconductive insulating layer. This electrostatic latent image is then developed to form a visible image by depositing finely divided electroscopic marking particles on the surface of the photoconductive insulating layer. The resulting visible image is then transferred from the electrophotographic substrate to a necessary member, such as, for example, an intermediate-transfer member or a print substrate, such as paper. This image developing process can be repeated as many times as necessary with reusable photoconductive insulating layers.
In image-forming apparatus such as copiers, printers and facsimiles, electrophotographic systems in which charging, exposure, development, transfer, etc. are carried out using electrophotographic photoreceptors have been widely employed. In such image-forming apparatus, there are ever-increasing demands for speeding up of image-formation processes, improvement in image quality, miniaturization and prolonged life of the apparatus, reduction in production cost and running cost, etc. Further, with recent advances in computers and communication technology, digital systems and color-image output systems have been applied also to the image-forming apparatus.
Electrophotographic imaging members (photoreceptors) are known. Electrophotographic imaging members are commonly used in electrophotographic processes having either flexible-belt or rigid-drum configurations. These electrophotographic imaging members sometimes comprise a photoconductive layer including a single layer or composite layers. These electrophotographic imaging members take many different forms. For example, layered photo-responsive imaging members are known in the art. U.S. Pat. No. 4,265,990 to Stolka et al. describes a layered photoreceptor having separate photogenerating and charge-transport layers. The photogenerating layer disclosed in Stolka is capable of photogenerating holes and injecting the photogenerated holes into the charge-transport layer. Thus, in the photoreceptors of Stolka, the photogenerating material generates electrons and holes when subjected to light.
More advanced photoconductive photoreceptors containing highly specialized component layers are also known. For example, a multi-layered photoreceptor employed in electrophotographic imaging systems sometimes includes one or more of a substrate, an undercoating layer, an intermediate layer, an optional hole- or charge-blocking layer, a charge-generating layer (including a photogenerating material in a binder) over an undercoating layer and/or a blocking layer, and a charge-transport layer (Including a charge-transport material in a binder). Additional layers such as one or more overcoat layer or layers are also sometimes included.
In view of such a background, improvement in electrophotographic properties and durability, miniaturization, reduction in cost, and the like, in electrophotographic photoreceptors have been studied, and electrophotographic photoreceptors using various materials have been proposed.
Production of a number of arylamine compounds, such as arylamine compounds that are useful as charge-transport compounds in electrostatographic imaging devices and processes, often involves synthesis of intermediate materials, some of which generally are costly and/or time-consuming to produce, and some of which involve a multi-step process. One such intermediate product is the arylamine N,N-di(4-propanoic acid)-4-aminobiphenyl, which is itself useful as a charge-transport compound in electrostatographic imaging devices and processes. Even production of this intermediate compound currently involves a long, costly process.
Currently, arylamine-derivative hole-transporting molecules are prepared by a process that includes reducing or hydrogenating a double bond using compressed hydrogen gas. For example, N,N-di(4-propanoic acid)-4-aminobiphenyl has been produced by selectively reducing N,N-di(4-propenoic acid)-4-aminobiphenyl using compressed hydrogen (H2) gas. While known and useful on a small, laboratory scale, this method is not conducive to large scale production of arylamine-derivative hole-transporting molecules, because it is costly and poses safety concerns.
First, hydrogen gas is a highly diffusible and highly combustible gas. The safety requirements for equipment and facilities for using hydrogen gas are strict, and altering equipment and facilities to meet or exceed the safety requirements for larger scale hydrogenation reactions could be very costly, particularly in light of the small volume necessary for the preparation of arylamine molecules.
Second, the efficiency of conventional hydrogenation reactions using compressed hydrogen gas depends on converting large amounts of the hydrogen gas to the liquid phase. In order to increase efficiency, elevated pressure and temperature, which would require specialized mixing equipment, would be necessary, and would, in turn, increase production costs.
Accordingly, improved processes providing safe, cost-effective and efficient methods for selective hydrogenation are desired for producing arylamines, such as N,N-di(4-propanoic acid)-4-aminobiphenyl, and similar compounds.
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1. Field of the Invention
The field of this invention relates generally to the field of the exercise clothing and more particularly toward a garment to be used in outdoor sports where protection from the sun is sought that also provides a hydration means.
2. Description of the Prior Art
Water sports are a very popular recreational activity worldwide. Typical water sports include water skiing, swimming, surfing, windsurfing, jetskiing and many other activities. One consideration when participating in these activities is keeping warm and another is keeping free of unhealthy ultraviolet rays from the sun. An additional consideration is the need to keep hydrated due respiration and exertion during participation.
One way to keep warm is the use of a wetsuit to keep body heat in. One shortcoming of wetsuits is a rash that is commonly caused by the seams in the neoprene typically used against the skin of the wearer. To overcome this problem, rash guards came into use for the user to wear underneath the wetsuit to protect the skin.
Over time, rash guards began to be used even when there was no wetsuit in order to protect the exposed skin from the sun and have been manufactured with SPF materials. In recent years, a new water sport has taken the water sports industry by storm and that is stand up paddling (SUP). SUP involves standing on a board like a surfboard and paddling with a paddle in a standing position to propel the rider forward. During this activity, it is not uncommon to wear a rash guard to protect from the sun.
Like other outdoor sports, such as cycling and hiking, there is a combined need for sun protection as well as an easy means of hydration. In the past, hydration was provided for non-water outdoor sports through water bottles or bladders filled with water that could be attached to clothing or a backpack. The instant invention seeks to provide an improved hydration/sun protection product that is a single garment that provides sun protection and a pocket for the placement therein of a hydration bladder.
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1. Technical Field
Embodiments of the disclosure relate to data bus protocols, and more particularly to implementations of a deterministic protocol on a shared data bus where nodes on the data bus have a pre-negotiated protocol for message scheduling.
2. Description of the Related Art
Avionics Full-Duplex Switched Ethernet (AFDX) is defined in the Aeronautical Radio, Incorporated (ARINC) standard ARINC 664—Part 7. This standard defines how Commercial Off-the-Shelf (COTS) networking technology will be used for future generation Aircraft Data Networks (ADN). AFDX defines a low-level network and protocol to communicate between end systems in aircraft. AFDX is based on Ethernet, however, AFDX also extends standard Ethernet to provide high data integrity and deterministic timing. Determinism is defined as controlling the maximum transmission delay through the network. One enabler of such control is precisely controlling the bandwidth allocation. Thus a deterministic network or a network operating with deterministic timing, controls the bandwidth allocation so that each node in the network can transmit a predetermined amount of data within a predetermined maximum time period. The ARINC 664 specification is herein incorporated by reference.
AFDX (also known as ARINC 664) is essentially a switch-based network solution to the point-to-point wiring of the Aeronautical Radio, Incorporated (ARINC) standard ARINC 429. Implementing the older ARINC 429 standard, dedicated wires directly connect individual end systems (source or destination nodes) to one another, with a separate wire pair required for each direction, and with both directions operating at a relatively slow maximum data rate. In contrast to ARINC 429, AFDX utilizes a single high data rate bidirectional connection to a centrally located switch to/from each source and destination node comprising the system network. In addition data to/from each end system is time division multiplexed over one physical path (wire pair or photonic connection) in each direction to/from the switch. These differences for ARINC 664 dramatically reduce the wiring required compared to ARINC 429 and offer faster speed. The ARINC 429 specification is herein incorporated by reference.
Thus, ARINC 664 requires switches to interconnect end systems. These switches take up space, require electrical power and add weight. Additional weight may be added by sizing the electrical power generation & distribution system (EPGDS) to support the additional power required by the switches.
Space-based vehicles are especially sensitive to weight and power requirements for network buses. Weight impacts for systems used in space applications arise from three sources: 1) the physical weight of the components (i.e., the switch weight); 2) the network interconnect topology affects wire weight; and 3) the power required to run the network infrastructure (i.e., switches) affects the size/weight of the electrical power generation & distribution system (EPGDS) at ˜0.8 lbs/watt of power consumed.
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) standard IEEE 802.3 defines wired Ethernet. 100Base-T Ethernet (100 Mbps) or Gb Ethernet (1 Gbps) can be configured as a switch-less shared bus network using carrier sense multiple access with collision detection (CSMA/CD) similar to the original coaxial cable Ethernet networks. Unlike switched Ethernet or AFDX networks, CSMA/CD networks cannot guarantee that a message would be transmitted within a predetermined time. The IEEE 802.3 specification is herein incorporated by reference.
The Institute of Electrical and Electronics Engineers, Inc. (IEEE) standard IEEE 1394 defines a serial bus interface that offers high-speed communications and time dependent, guaranteed throughput (isochronous) real-time data services. IEEE 1394, with the help of software can be used to create a shared bus network (i.e., a network without switches or routers). Request For Comments (RFC) Internet standards memoranda document RFC 2734 specifies how to run Internet Protocol, Version 4 (IPv4) over IEEE 1394 and RFC 3146 specifies how to run Internet Protocol, Version 6 (IPv6) over IEEE 1394. Both RFC 2734 and 3146 require using the asynchronous stream mode of data transfer. However, IPv4 and IPv6 do not provide any measure of latency control. Rather, they provide a guaranteed delivery class of service, with handshakes and acknowledgments for each complete transaction. Thus, neither RFC 2734 nor 3146 provide for a deterministic (time dependent with guaranteed throughput) network or data bus. The IEEE 1394, RFC 2734, and RFC 3146 specifications are incorporated herein by reference.
The IEEE 1394 standard includes IEEE 1394a (400 Mbits/s and IEEE 1394b (800 Mbits/s). IEEE 1394b added a new arbitration scheme. For data to be sent or received optimally, the 1394 devices must determine the order and timing of the transmission of data from each of the devices. In IEEE 1394b the data transmission now is continuous dual simplex; one copper-wire pair or photonic cable strand is continuously transmitting data in each direction (one for data, one for next bus access negotiation) thus resulting in a much simpler and more efficient data transmission process than IEEE 1394a.
The dual simplex nature of the IEEE 1394b bus architecture allows for the implementation of the highly efficient bus arbitration scheme, known as BOSS (Bus Owner Supervisor Selector) which implements simultaneous, pipelined arbitration so that the arbitration protocol runs in parallel with data transmissions. The IEEE 1394a (legacy version) is different in the sense that it alternates between data transmission and arbitration. The arbitration is dependant on the use of short or long time gaps of specified lengths to signal bus availability for various packet types in 1394a. As a result of this dependency there is a delay before a device wins an arbitration and is allowed to start sending its data. But, with the BOSS scheme, the currently transmitting node (device termed as the “Boss”) decides which node gets to transmit next at the end of its transmission. When the Boss is finished transmitting, it knows where to send the grant. This immediate decision process saves the arbitration time, thus removing the need for arbitration time gaps.
IEEE 1394 supports three transfer modes: asynchronous, asynchronous stream and isochronous transfer. In the asynchronous transfer mode, data is guaranteed to be delivered without error to the receiver, where in case there are some disturbances in the bus, the data is sent again. The receiving node hardware will send an acknowledgement as to whether or not that the packet was received correctly. Thus, asynchronous transactions are deemed “guaranteed delivery”, though no latency limit, or bandwidth, is guaranteed. Asynchronous messages are transmitted after completing all competing isochronous message traffic based on arbitration until the end of each repeating 125 uSec cycle.
Isochronous message packets are transmitted in a broadcast fashion and do not require or accommodate acknowledgements from individual recipients. They are thus not considered to provide guaranteed knowledge of delivery. Because of their priority over asynchronous messages, they provide instead a guaranteed bandwidth.
The last message type, called “asynchronous streaming”, is similar to isochronous packets in that it does not require or accommodate receipt messages from individual recipients but that it may also be transmitted in any portion of the repeating 125 uSec cycles. It therefore provides guaranteed bandwidth, but not guaranteed delivery, to individual recipients. While asynchronous streaming packets provide guaranteed bandwidth once the sending device has access to the bus, there is no guarantee that a device with asynchronous streaming packets will be able to access the bus in a predetermined time.
The SAE standard AS5643 (MIL-1394) also defines a serial bus interface that offers high-speed communications. MIL-1394 is a military version of IEEE 1394. MIL-1394 provides for using time division multiple access (TDMA) to form a shared bus network. A MIL-1394 TDMA network is controlled at the application layer (i.e., the assignment of time slots to each end system is controlled by a software application at one or more nodes). However, MIL-1394 does not take advantage of the BOSS (described later) function in IEEE 1394b. Furthermore, MIL-1394 requires a more complicated management of time slots to provide latency control. AFDX, with BAG groups, is easier to schedule and use. The SAE standard AS5643 (MIL-1394) is herein incorporated by reference.
Accordingly, there is a need for a switchless deterministic shared bus network that minimizes weight and power while providing deterministic data transport.
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While heavy duty bumper systems have been built which are capable of meeting the above noted collision impact requirements, they have normally been relatively complicated of design and therefore costly to manufacture as well as being heavier than is to be desired.
The present bumper system is a companion to the one shown in my application Ser. No. 528,403 "Energy Absorbing Vehicle Bumper" filed Sept. 1, 1983, now U.S. Pat. No. 4,509,782. It has been found that by using a relatively rigid, though deflectable, hollow core element formed of a high strength plastic in place of a resilient foam core material several advantages inhere. First, by utilizing a unique core element design the bumper system can absorb higher impact loads before experiencing damage to system components. More specifically, the present bumper system can absorb higher impact loads than my earlier system before breaking or rupturing the energy absorbing core element. Next, the uniquely configured, hollow core element has further reduced the weight of the bumper system as well as simplifying its construction.
In addition, the following patents are illustrative of bumper systems which have been designed to perform in environments similar to that of the subject invention:
U.S. Pat. No. 3,897,095 "Resilient Bumper Assembly"--Glance et al
U.S. Pat. No. 3,902,748 "Pneumatic Energy Absorbing Bumper System For Motor Vehicles"--Bank et al
U.S. Pat. No. 3,989,292 "Semi-Pneumatic Energy Absorbing Bumper System For Motor Vehicles"--Bank et al
U.S. Pat. No. 4,103,951 "Semi-Pneumatic Energy Absorbing Bumper System For Motor Vehicles"--Bank et al
None of the foregoing structures disclose or suggest applicant's unique bumper system.
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1. Field of the Invention
This invention provides a new use for an old product, namely a novel way to prevent the transmission of bluetongue virus from the Culicoides gnat to sheep by treating the skin of the sheep and, more particularly the skin upon the back of the sheep to a chemotherapeutic dosage of sulfamoyl phenyl esters of organic phosphates.
2. Description of the Prior Art
The raising of sheep for both wool and food is an important industry in the United States, as well as in many other countries. This industry is currently being threatened by a viral disease known as bluetongue. Bluetongue was first reported in United States in 1952 but already is felt responsible for the decimation of the Big Horn sheep population of West Texas in 1967. While the effects of bluetongue are largely felt in the domesticated sheep industry, the disease can attack any ruminant with mortality being documented following disease outbreaks in mule deer, antelope, Big Horn sheep, as well as cattle. Death losses from bluetongue is usually in the 10-30% range. Abortion, early embryonic death, and malformed lambs are also a result of the disease. Another great economic loss caused by the disease is the loss of weight of feeder lambs and young sale rams which contract the disease. Another common occurrence due to the disease is the sterilization of rams for a period of up to six months following recovery from the disease even though the disease may have been mild. Sterilization may be permanent in more severe cases. Obviously, this problem can lead to late lambs or no lambs in small flocks.
The bluetongue virus is carried from one animal to another by a small gnat called Culicoides. When the gnat bites an infected animal it acquires the virus and carries it to the next animal it feeds on. Presently, there are two approaches to controlling the gnat to prevent disease. The first is to reduce the breeding sites of the gnat and the second is use of chemical pesticides. Presently there are no pesticides registered for gnat control and therefore reducing the breeding areas is the most important method. Draining stagnant pools of water significantly reduces or eliminates the breeding site of the gnats. Spraying breeding sites to control gnats is proven not economically feasible. It has been shown that even if all gnats are killed in one area, by the next day new ones move in from surrounding areas. Heretofore, there has not been an effective method for controlling transmission of the bluetongue disease.
Sulfamoylphenyl esters of organic phosphates have been used for controlling parasites attacking warm blooded animals as disclosed and claimed in U.S. Pat. No. 3,179,560 issued to R. I. Hewitt. Such esters have been found to be very effective systemic insecticides for destroying the parasites. As shown in the same patent, the compound has been found effective against gastrointestinal nematodes in sheep. In the treatment of nematodes, the compound was given orally.
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The present invention relates to a thermal analysis system such as a differential scanning calorimeter and a method of drying the same.
Conventionally, with a thermal analysis system, such as a differential scanning calorimeter, having a furnace body therein, an analysis has been performed by: loading a sample (a specimen) in the furnace body; using a heating device and a cooling device to raise and decrease the temperature of the sample to change the sample in temperature; and measuring absorption and radiation of heat by the sample in the form of an amount of heat. During such measurements, the temperature of the furnace body is lowered to e.g. a temperature of −70 to −150° C. constantly or temporarily. That is to say, the furnace body portion and its surroundings and the like remain cooled successively, and stay in the situations easy to cause condensation. Particularly when a sample is loaded into and unloaded from the thermal analysis system, opening an opening-and-closing cover of the thermal analysis system causes the outside air to flow into the furnace body and the inside of the case, which can cause condensation on the furnace body portion and its surroundings, and further on a temperature sensor such as a thermocouple and others, leading to adhesion of water droplets and frost thereon. When measurements are performed under the situation where the frost is thus formed, fluctuations arise in the measured temperatures to generate noises in data to be measured. This has been a cause of the impossibility of acquisition of exact measurement values. Hence, a method including uninterruptedly supplying a predetermined amount of dry gas to the thermal analysis system thereby to keep the inside of the analysis system in a dried state, and manually supplying a large amount of additional dry gas on an as-needed basis has been practiced.
Further, a method of performing automatic supply of dry gas instead of manual supply like this thereby to suppress the occurrence of condensation has been disclosed in e.g. JP-A-10-104182.
In Patent Document 1, an open-and-close sensing switch for sensing open and close states of an opening-and-closing cover provided on an outer case making an outside housing of the thermal analysis system is provided, and the supply of dry gas is controlled by ON/OFF signals from the open-and-close sensing switch. In other words, as a large amount of dry gas is supplied to the surroundings of the furnace body inside the thermal analysis system when the opening-and-closing cover is opened for loading and unloading a sample, intrusion of the outside air through the opening-and-closing cover can be cut thereby to prevent condensation and frost from forming around the furnace body.
However, as for the thermal analysis system used in JP-A-10-104182, it is expected that the humidity inside the thermal analysis system is equivalent to that of the outside air at the time when the power source is activated, i.e. before the cooling device is actuated. In that situation, actuating the cooling device will cause generation of condensation and frost and the like in the thermal analysis system owing to the moisture remaining in the analysis system. The thermal analysis system has the disadvantage that the moisture, particularly the moisture adhering to a cooling module and the like cannot be removed easily even by supplying dry gas or heating surroundings of a specimen thereafter. Therefore, the moisture which has adhered to the inside of the analysis system at the time of measurement cannot be removed sufficiently only by automatically supplying an additional dry gas at the time of opening and closing the opening-and-closing cover as described in JP-A-10-104182. This moisture causes the temperature to fluctuate and generates noises in measurement data.
In addition, a measure including manually supplying an additional dry gas thereby to dry the inside of the analysis system, and heating a heater block around a specimen thereby to accelerate the drying before the cooling device is actuated is taken separately. However, there is the problem that in the case where the drying is performed through both drying by gas and heating of the heater block before actuation of the cooling device, excessively raising the drying temperature damages the cooling module (especially, a leading end of the cooling rod) inserted in and connected with the thermal analysis system when the cooling device is e.g. an electric cooling device. Since the preferable drying time and the drying temperature vary depending on a cooling method including the type of a cooling device and its connection mode as stated above, their management has been a difficult and troublesome work.
The invention was made in consideration of the foregoing problems. Therefore, it is an object of the invention to provide a thermal analysis system and its drying method, by which working efforts by hand can be reduced by adequately selecting a dry condition in accordance with the connection mode of the cooling device and controlling a drying operation and moreover the moisture and the like can be removed without fail.
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1. Field of the Invention
This invention provides an easy to open container/closure assembly, more particularly, an easy to open closure/container assembly having a tamper-indicating feature.
2. Discussion of the Art
Two main types of bottle/closure systems that utilize breakaway bands for indicating tampering are currently commercially available. Both types have certain drawbacks. The first type locks the tamper-indicating band in place. This locking mechanism requires simultaneous application of two of forces: (1) the force to overcome thread and sealing surface friction to remove the cap and (2) the force to break the tamper resistance band, thereby resulting in high removal torques and high standard deviations of removal torque. The lowest removal torque that can be achieved with this system is approximately 18 inch pounds on average. This force is too high for elderly users and users suffering from arthritis. The second type involves the separation of the opening force from the force required to remove the tamper-indicating band, by allowing approximately 180° of free rotation of the cap before breakage of the tamper band is initiated. Accordingly, the closure is subject to substantial “back-off” (i.e. loosening) and possible leakage during distribution. This type of closure also does not provide any audible feedback in the area between cap opening and band breakage to reassure the consumer of safety. In both of these types of tamper resistance mechanisms, the force that breaks away the tamper resistant band is angular or circumferential and is applied by the torque of removing the closure.
U.S. Pat. No. 4,991,731 describes problems encountered when packaging consumable products in sealed containers. These problems are described below.
Due to concerns about material cost, container weight, and breakage, suppliers of consumable products desire to manufacture the container from a plastic substance, such as polypropylene, which is relatively inexpensive and may be colored or translucent. A problem arises when attempting to provide a cap for a plastic container, wherein the cap maintains a hermetic seal. Because it is difficult to maintain a hermetic seal in a plastic container, and conventional metal caps and plastic containers expand by a dissimilar amount, metal caps, by themselves, do not maintain a hermetic seals consistently on plastic containers when subjected to retort conditions.
During thermal treatment such as retort conditions, heat causes polymer relaxation or shrinkage, especially in the upper neck portion of the container. Injection or extrusion molded plastic bottles are formed by melting and pressure forming, which create stress and memory in the molecules of the polymer. The introduction of heat during the retort process causes those molecules to relax, so as to actually shrink the diameter of the neck portion of the container. This shrinkage causes severe problems in maintaining a conventional metal cap on a plastic bottle. This shrinkage may also prevent the use of a conventional plastic cap with a plastic bottle.
The problems mentioned above can be overcome by applying a substantial amount of torque when initially capping the bottle. However, the amount of torque necessary to maintain a conventional cap on a plastic bottle is so high that a person would not be able to easily twist the cap off the bottle following retort. Other alternatives would be to use an extremely expensive plastic to fabricate the bottle so that the plastic would not shrink at retort temperatures and could maintain an internal vacuum without distortion.
Screw on bottle caps have a tendency to loosen from a tightened condition on a threaded bottle neck finish. This tendency to loosen is often referred to as “back off”. This tendency to loosen has a number of causes, including, for example, temperature change, creep in the bottle and cap materials, relaxation of a liner or sealant material, and vibration during handling and shipping. This problem is more frequently encountered when the screw threads have a high pitch to enable the cap to be quickly removed and reinstalled with limited twisting action. Loose caps create problems for the manufacturer and retailer of packaged goods and even for the ultimate user. Loose caps can falsely indicate tampering, and, of course, allow spillage or leakage of the contents as well as entrance of contaminants into the container. A good moisture seal is especially important, for example, when pharmaceuticals and dietary supplements can be adversely affected by excess increases of or by excess decreases of moisture content. While “anti-back off” features are known in the industry, these features have not generally been available for bottles intended for use by elderly persons having limited strength and by sufferers from arthritis.
U.S. Pat. No. 6,296,130, EP 0 864 504 A1, WO 01/15988 A1, U.S. Patent Application Publication 2003/0160020 A1, and U.S. Pat. No. 4,349,116 disclose closure/container assemblies having “anti-back off” features. It is apparent that there is a need for an improved container/closure assembly that provides system seal integrity during retort, as well as permitting the sanitary opening of the container in a single action motion with a very low removal torque.
U.S. Pat. No. 4,813,561 describes containers and closures having tamper resistance bands. This patent describes ratchet teeth on a closure and sets of corresponding teeth on the container that engage below a retaining ledge. The sets of teeth on the container create gaps or spaces into which the tamper band can deform upon opening. However, due to the exact correspondence and alignment of the ratchet teeth on the container and closure, significant torque is still needed to break the tamper band bridges and remove the closure.
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Gibberellic acid (GA3) is the most important gibberellin, a class of diterpenoid acids that function as plant growth regulators (Jefferys, E. G., Adv. Appl. Biol. 13:283-316 (1970)). GA3 affects stem elongation, elimination of dormancy, flowering, sex expression, enzyme induction and leaf and fruit senescence. GA3 is a high-value, industrially-important, biochemical with various applications in agriculture (L. M. Pastrana et al., “Interactions affecting gibberellic acid production in solid-state culture: A factorial study”; Enzyme and Microbial Technology 17:784-790 (1995), citing to Kumar, P. K. R., and Lonsane, B. K., Appl. Microbiol. Biotechnol. 34:145-148 (1990)). However, its high cost has restricted its use to premium crops (Jefferys, E. G., Adv. Appl. Biol. 13:283-316 (1970)).
GA3 has been obtained by chemical synthesis, extraction from plants and by microbial fermentation. Stereospecific chemical synthesis involves multiple steps and the use of expensive reagents. To date, chemical synthesis is not economically competitive with fermentation techniques. Direct extraction of GAs from higher plants is not economically feasible due to extremely low concentration of GAs in plant tissue. A large number of bacteria, actinomycetes and yeast cultures have been reported to produce GA3 or GA3-like substances, but most do not produce GA3 at commercially-feasible levels. Today, GA3 is produced by fermentation, mostly from fungi.
Fermentation Methods
GA3 production in fungal culture includes liquid surface fermentation, submerged fermentation, and solid state fermentation.
Liquid Surface Fermentation (LSF)
Liquid surface fermentation (LSF), often referred to as surface fermentation, was employed in earlier years for the production of GA3 but suffered from low yield (e.g. 3.3-9.2 g of crude powdered GA3 from 130 liters of medium) problems with scalability, contamination and more, and was discontinued (P. K. R. Kumar and B. K. Lonsane, “Microbial production of Gibberellins: state of the art” in Advances in Applied Microbiology. 34: 29-140 (1989)).
Submerged Fermentation (SmF)
Currently, GA3 is largely produced by submerged fermentation (SmF) of the fungus Gibberella fujikuroi. The fungus known as Fusarium moniliforme is also used; F. moniliforme is the anamorph (asexual stage) of Gibberella fujikuroi. GA3 is also synthesized from several bacteria such as Azotobacter, and Azospirillium in culture medium and from wild strains of fungi such as Sphaceloma sp., Phaeosphaeria sp., and Neurospora sp.
The initial pH values generally employed by various workers are within the range 3.5-5.8, especially around pH 5.5. Id. pH was not usually controlled during fermentation and thus resulted in a final pH differing from the starting pH, with reports of the final pH of 3.9-5.2, 1.8-1.9, or even slight alkalinization. Id.
The effect of temperature on the production of GA3 is dependent on the strain employed. The optimal temperatures reported for the production of GA3 using G. fujikuroi or F. moniliforme include 25° C.; 28.5-29.5° C.; 30° C.; 34° C.; 29± 0.5° C.; 27° C.; and 28° C. (See Id.)
Different workers have used a variety of carbon sources for the production of GAs, as reported by different authors. A combination of readily and slowly metabolizable carbon sources gave a higher yield of GA3. Id. Use of molasses led to decreased but economically useful yields. Id. There was a 49% decrease in the yield of GAs with stearic acid as compared to sucrose. Use of dairy waste as carbon source resulted in 0.75 g GA3/liter in 12 days. The production was completely inhibited by 1 ppm geraniol due to total inhibition of cell growth. A direct proportional relationship has been shown between the initial concentration of nitrogen supplied in the medium and the rate of product formation as well as the amount of metabolite produced. Id. See also Jefferys, E. G., Adv. Appl. Biol. 13:283-316 (1970)
Trace elements such as Fe, Cu, Mn, Zn, Al and Ca are required in the fermentative production of GAs. Id. Trace elements may be expressly added in excess or in combination, as in Raulin-Thom medium, or sufficient trace elements may be present as impurities in other ingredients of the fermentation medium. Id.
Other growth factors such as vitamins or Yeast extract may improve yield; while other heavy metals or the use of lines steel or stainless steel fermentation tanks can decrease yield. Id.
Various processes for production of GA3 are described in U.S. Pat. Nos. 2,842,051, 2,865,812, 2,906,671, 2,906,673 and 3,021,261. U.S. Pat. No. 2,865,812 reported a yield of 630 mg/L in 664 hrs. Eleazar et al. (“Optimization of gibberellic acid production by immobilized Gibberella fujikuroi mycelium in fluidized bioreactors”, Journal of Biotechnology, 76, 147-155 (2000)) reported yields by submerged fermentation as high as 2.862 g/L.
Solid Substrate Fermentation (SSF)
SSF (Solid Substrate Fermentation) is defined as any fermentation process performed on a non-soluble material that acts both as physical support and source of nutrients, in the absence of free flowing liquid. No free-moving water is present, but there is enough moisture present for the growth and metabolism of the microorganism. The low moisture content means that fermentation can only be carried out by a limited number of microorganisms, mainly yeasts and fungi, although some bacteria have been used. Work on the production of GAs using SSF technique was initiated in the early 1980s and the initial studies gave variable yields. No information was available on the economics of the process until early 1987. Three cases were examined wherein the yield of GA3 under the SSF technique were 0.825, 1.05 and 1.54 g/kg of Dry Mouldy Bran. The yield of GA3 in the fed-batch SSF Process was 1.54 g/kg of Dry Mouldy Bran as compared to 1.05 g/kg of Dry Mouldy Bran in the batch SSF process. Id. One group reported a yield of 3 g/kg by SSF (Bandelier, S., Renaud, R., and Durand, A., “Production of Gibberellic acid by Fed-batch solid state fermentation in an aseptic pilot-scale reactor”, Process Biochemistry, 32:141-145 (1997)). B. Tudzynski (“Biosynthesis of gibberellins in Gibberella fujikuroi: biomolecular aspects”; Appl. Microbiol Biotechnol (1999) 52:298-310) reported that German Patent Number DD252000 also described processes for GA3 by submerged fermentation, and reported yields of 8 g/kg.
Art-Known Fermentation Techniques Remain Expensive
Despite advances in fermentation technology, the cost of production of GA3 has been a deterrent to its widespread use. Additional cost considerations include problems in the downstream processing and, given the potency of GA3 to plants, removal and disposal of contaminated wastewater.
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Patio torches, also know as lawn torches or garden torches, may be used to provide lighting or decoration. Sometimes, scented oils or insect repellant oils are burned in the patio torches for additional effect. A torch may include a refillable canister that accepts liquid fuel. Although, for safety reasons the torches are not usually filled when ignited, filling liquid fueled torches can be inconvenient. The top of the canister containing the charred and often sooty wick must be removed. A funnel must be used to prevent spilling of the flammable fuel when filling the canister. The top of the canister must then be handled a second time in order to replace it.
In addition to filling and other maintenance problems, the actual usefulness of the torches, both in terms of light or aroma given off and the ability to repel pests, may be less than desirable. The wick is often too small, relatively speaking, to provide an effective amount of combustion. Even with larger diameter wicks or wicks that are extendable to create a larger surface area, air and flame control may become problematic resulting in a flame that may still be too small, too smoky, or both.
What is needed is a device for addressing the above and related problems.
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Wireless communications access, on which our society and economy is growing increasingly dependent, is becoming pervasive in all aspects of daily societal functions. For example, wireless communication has become increasingly available to users on board mobile platforms such as land vehicles, aircraft, spacecraft, watercraft or the like. Wireless communication services for passengers of mobile platforms include Internet access, e.g., e-mail and web browsing, live television, voice services, virtual private network access and other interactive and real time services.
Wireless communication platforms for remote, hard to access, or mobile user terminals, e.g., mobile platforms, often use communication satellites that can provide service coverage over large geographic footprints, often including remote land-based or water-based regions. Generally, base stations, e.g., a ground base station, send information (e.g., data) to the user terminals through a bent pipe via one or more satellites. More specifically, the base stations send information on a forward link to the satellite that receives, amplifies and re-transmits the information to an antenna of one or more fixed or mobile user terminals. The user terminals, in turn, can send data back to the base stations via the satellite. The base stations can provide the user terminals with links to the Internet, public switched telephone networks, and/or other public or private networks, servers and services.
Modern satellites and other cellular communication systems often employ a number of spot beams providing a beam laydown that forms coverage over a geographic region that may be divided into a plurality of cells. In a communication system using spot beams, the same frequency may be used at the same time in two or more cells. These beams may be configured to maintain a predetermined co-polar isolation (e.g., carrier-to-interference ratio) value in order to minimize the interference among beams. This is called spatial isolation and spatial reuse. In one typical parlance, each spot beam may be assigned a color to create a color pattern that matches a frequency reuse pattern. Identical frequencies, then, may be reused by different beams with the same color.
These cellular communication systems often face a number of challenges in optimizing services for a variety of types of user terminals, while staying within system constraints. The systems often require high system capacity to provide simultaneous voice and data. Links providing voice services are often noise dominate and require high satellite antenna gain, whereas those providing data services often require optimization of opposing satellite-antenna criteria. That is, data links are often interference dominant and require high side-lobe suppression to provide a high signal-to-interference ratio.
Many modern cellular communication systems are often configured to permit communication by a variety of types of user terminals in the coverage region, which may benefit from different, sometimes-opposing satellite-antenna criteria for optimal performance. The different types of terminals may also benefit from different frequency reuse patterns and/or cell sizes. Small-sized handheld terminals often benefit from higher satellite antenna gain to close links with the satellite, and may also benefit from a medium-to-high-order frequency reuse with mid-sized cells. Mid-sized portable and vehicular terminals on the other hand often benefit from higher side-lobe suppression to provide a correspondingly higher signal-to-interference ratio, as well as a higher-order frequency reuse to provide higher-rate data services to a higher-density user base with micro-sized cells. And large-sized aeronautical and maritime terminals often benefit from a lower-order frequency reuse to provide data services to a lower-density user base with large-sized cells. And aeronautical terminals in particular often travel at high speeds, and may benefit from larger-sized cells to reduce the frequency of beam-to-beam handovers as they travel over the geographic region.
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The present invention relates to methods and systems for managing packet switched networks, such as Internet protocol networks.
The primary elements of an existing intelligent network are a switching system, a signaling network, a centralized database, and an operations support system which supports the database. In general, the switching system intercepts a call from a call source, and suspends call processing while launching a query through the signaling network to the centralized database. The database, in turn, retrieves the necessary information to handle the call, and returns that information through the signaling network to the network switch, which may be part of a network operations center, so that the call can be completed. The operations support system administers the appropriate network and customer information that resides in the database.
The intelligence of the intelligent network is found at the service control points. A service control point is an on-line, real-time, fault-tolerant, transaction-processing database which provides call-handling information in response to network queries. The signaling network is made up of signal transfer points. A signal transfer point is a packet switch found in the common-channel signaling network. The signal transfer point is used to route signaling messages between network access nodes, such as switches and service control points. Signaling System 7 is a common communications protocol used in common-channel signaling networks having associated circuit switched networks for completing calls.
Although circuit switched connections that connect a call between network switches to complete calls are very common, packet switched networks such as Internet protocol (IP) networks are being used to complete calls for an increasing number of applications. As such, a network operations center for managing a packet switched network may require an increasing number of application servers to offer, for example, voice, fax, and video services over the packet switched network which may be an Internet protocol (IP) network.
Current solutions for implementing these additional application servers are turnkey. That is, existing solutions, although used in many applications that are commercially successful, were designed to work independently of any existing network. More particularly, the databases associated with these additional application servers are usually located at the servers within the network operations center that manages the packet switched network.
Further, these databases handle call routing with static routing tables based on area codes. However, local number portability makes this a much more complicated task.
For the foregoing reasons, there is a need for a method and system for managing a packet switched network that facilitates database implementation.
It is, therefore, an object of the present invention to provide a method and system for routing a call at least partially over a packet switched network that simplifies database implementation by utilizing an interface to the existing signaling network and associated centralized database.
In carrying out the above object, a method for routing a call at least partially over a packet switched network is provided. The method comprises receiving the call at a network operations center in communication with a server, and sending a first query from the server to a gatekeeper. The gatekeeper sends a second query over a signaling network to a service control point in response to the first query. A routing message from the service control point is received at the gatekeeper in response to the second query. The method further comprises communicating the routing message from the gatekeeper to the server, and routing of the call to a call destination in accordance with the communicated routing message. The call is at least partially routed over the packet switched network, which may be an Internet Protocol (IP) network.
Preferably, the network operations center has a plurality of different servers. Examples of servers that may be located at the network operations center are: a video server, a voice server, a fax server, and a directory server. Of course, other servers may be located at the network operations center in addition to or as an alternative to those listed previously. Further, in a preferred embodiment, the gateway and the server are located within the network operations center.
Further, in carrying out the present invention, a system for routing a call at least partially over a packet switched network is provided. The system comprises a network operations center in communication with a server for receiving the call, and a gatekeeper. The server is operative to send a first query upon receiving the call. The gatekeeper receives the first query from the server, and is operative to send a second query over a signaling network to a service control point upon receiving the first query. The gatekeeper is further operative to receive a routing message from the service control point in response to the second query. The gatekeeper communicates the routing message to the server. The server routes the call in accordance with the communicated routing message. The call is at least partially routed over the packet switched network.
The network operations center may have any number of servers and may include a video server, a voice server, a fax server, a directory server, or any other server or combination of servers. Preferably, the gateway and server are located within the network operations center. Further, the packet switched network may be, for example, an Internet Protocol (IP) network.
Still further, in carrying out the present invention, a system for routing a call is provided. The system comprises an intelligent network, a packet switched network, a network operations center, and a gatekeeper. The network operations center communicates with a server that is operative to route the call at least partially over the packet switched network in accordance with a communicated routing message.
The advantages associated with embodiments of the present invention are numerous. For example, methods and systems of the present invention allow servers to query a service control point by utilizing the gatekeeper. As such, embodiments of the present invention may handle calls that require information from, for example, a local number portability database, an 800 number service database, or any other database that normally exists in an existing intelligent network, in addition to new databases that may not yet be implemented in the service control point, including new databases intended specifically for access by the network operations center.
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This invention relates generally to a method for preparing amine boranes from sodium borohydride and an amine salt.
Processes for production of amine boranes from sodium borohydride and amine salts are well known, and the reaction usually is carried out in an organic solvent in which sodium borohydride is soluble. For example, U.S. Pat. No. 6,060,623 describes preparation of amine boranes from sodium borohydride and amine salts in an organic solvent, e.g., 1,2-dimethoxyethane. In this process, the initial reaction mixture must be distilled to remove the solvent prior to isolation of the amine borane product.
The problem addressed by this invention is to provide a more efficient process for producing amine boranes from sodium borohydride and amine salts, without the use of additional solvents for the borohydride starting material.
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The present invention relates to a method of cooling gas-permeable materials having highly temperature-dependent coefficient of thermal conductivity. More particularly, it relates to a method of cooling such materials in a shaft-shaped chamber wherein a loose material is fed in counter stream to a gaseous cooling medium supplied from below downwardly and wherein the stream of the cooling medium is subdivided into two partial streams.
Methods of cooling of the above-mentioned general type are known in the art. In a known method, a loose material which travels from above downwardly in a shaft-shaped chamber in a counter stream to a gaseous cooling medium, advantageously air or inert gas, is pierced by the cooling medium. The cooled cooling medium is normally directed into the lower part of the chamber and the heated cooling medium is withdrawn from the upper part of the chamber. Subsequently, the heated cooling medium can in some cases be cooled, with heat recovery by supplying the same into a heat exchanger, waste-heat boiler, or another cooling device. After this, the cooling medium can be returned into the process by supplying into the lower part of the shaft-shaped chamber.
At present the above-described process, particularly for so-called dry coke cooling, became very important. This development is based upon the consideration that the previously known conventional methods of coke cooling which involve quenching the glowing coke with water in special quenching towers, is extremely unfavorable in the sense of the energy utilization or energy recovery as well as the environment protection. In the conventional water quenching method, the heat which is withdrawn with the quenching water escapes into the surrounding atmosphere without being used. For example, heat is carried away in the form of vapor clouds in the air and/or with the flowing off quenching water. In contrast, when loose materials are cooled by gaseous cooling medium, as described above, a greater part of heat of the glowing coke can be recovered from the cooling medium in a waste-heat boiler or the like. The so-called dry coke cooling is a preferable application area of the present invention which is, however, not limited to the same. It has been recognized however, that the downward movement of the coke to be cooled in the shaft-shaped chamber is characterized by different speeds. Similarly, the gas stream through the cross-section of the chamber is also non-uniform in many cases. Both these phenomena can naturally cause a non-uniform cooling of the coke, and the cooling is performed slower, particularly in the upper part of the chamber.
The German Auslegeschrift No. 2,432,025 describes an arrangement for dry quenching of coke, in which the gaseous cooling medium is supplied in two partial streams into the cooling chamber. One of the partial streams is directed to the bottom of the chamber and particularly to a compact layer located in this region. The second partial stream is supplied through a so-called stream divider into the interior of the chamber and there exits in the region of the central axis to the compact layer. The above-mentioned German reference does not contain any data about special functions and operation to be performed by the second partial stream of the cooling medium or the manner of dividing the partial streams. The arrangement disclosed in this reference pursues the only purpose to provide of a best possible uniform movement of the material to be treated with a best possible uniform division of the cooling medium.
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The disclosure relates to a footrest, and a method of making a footrest.
There is interest in the manufacture of footrests that are operable, easy to assemble and lightweight. There is further interest in providing a footrest that does not require a large area of storage space.
In many embodiments, these footrests have a resting area where users can place their feet, and a support mechanism used to hold the resting area. However, these footrests may be burdensome to carry, difficult to assemble and take up a large area of space.
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The present invention is a surgical device and method. More specifically, it is a surgical device and method which provides an ultrasound transducer assembly mounted on a catheter shaft for ultrasonically coupling to a region of tissue in a body of a patient, and still more specifically for ultrasonically coupling to a circumferential region of tissue at a location where a pulmonary vein extends from an atrium.
The terms xe2x80x9cbody space,xe2x80x9d including derivatives thereof, is herein intended to mean any cavity or lumen within the body which is defined at least in part by a tissue wall. For example, the cardiac chambers, the uterus, the regions of the gastrointestinal tract, and the arterial or venous vessels are all considered illustrative examples of body spaces within the intended meaning.
The term xe2x80x9cbody lumen,xe2x80x9d including derivatives thereof, is herein intended to mean any body space which is circumscribed along a length by a tubular tissue wall and which terminates at each of two ends in at least one opening that communicates externally of the body space. For example, the large and small intestines, the vas deferens, the trachea, and the fallopian tubes are all illustrative examples of lumens within the intended meaning. Blood vessels are also herein considered lumens, including regions of the vascular tree between their branch points. More particularly, the pulmonary veins are lumens within the intended meaning, including the region of the pulmonary veins between the branched portions of their ostia along a left ventricle wall, although the wall tissue defining the ostia typically presents uniquely tapered lumenal shapes.
Many local energy delivery devices and methods have been developed for treating the various abnormal tissue conditions in the body, and particularly for treating abnormal tissue along the body space walls which define the various body spaces in the body. For example, various devices have been disclosed with the primary purpose of treating or recanalizing atherosclerotic vessels with localized energy delivery. Several disclosed devices and methods combine energy delivery assemblies in combination with cardiovascular stent devices in order to locally deliver energy to tissue in order to maintain patency in diseased lumens such as blood vessels. Endometriosis, another abnormal wall tissue condition which is associated with the endometrial cavity of the female and is characterized by dangerously proliferative uterine wall tissue along the surface of the endometrial cavity, has also been treated by local energy delivery devices and methods. Several other devices and methods have also been disclosed which use catheter-based heat sources for the intended purpose of inducing thrombosis and controlling hemorrhaging within certain body lumens such as vessels.
Further, more detailed examples of local energy delivery devices and related procedures such as those of the types just described above are variously disclosed in the following references: U.S. Pat. No. 4,672,962 to Hershenson; U.S. Pat. No. 4,676,258 to InoKuchi et al.; U.S. Pat. No. 4,790,311 to Ruiz; U.S. Pat. No. 4,807,620 to Strul et al.; U.S. Pat. No. 4,998,933 to Eggers et al.; U.S. Pat. No. 5,035,694 to Kasprzyk et al.; U.S. Pat. No. 5,190,540 to Lee; U.S. Pat. No. 5,226,430 to Spears et al.; and U.S. Pat. No. 5,292,321 to Lee; U.S. Pat. No. 5,449,380 to Chin; U.S. Pat. No. 5,505,730 to Edwards; U.S. Pat. No. 5,558,672 to Edwards et al.; and U.S. Pat. No. 5,562,720 to Stern et al.; U.S. Pat. No. 4,449,528 to Auth et al.; U.S. Pat. No. 4,522,205 to Taylor et al.; and U.S. Pat. No. 4,662,368 to Hussein et al.; U.S. Pat. No. 5,078,736 to Behl; and U.S. Pat. No. 5,178,618 to Kandarpa.
Other previously disclosed devices and methods electrically couple fluid to an ablation element during local energy delivery for treatment of abnormal tissues. Some such devices couple the fluid to the ablation element for the primary purpose of controlling the temperature of the element during the energy delivery. Other such devices couple the fluid more directly to the tissue-device interface either as another temperature control mechanism or in certain other known applications as an actual carrier for the localized energy delivery, itself.
More detailed examples of ablation devices which use fluid to assist in electrically coupling electrodes to tissue are disclosed in the following references: U.S. Pat. No. 5,348,554 to Imran et al.; U.S. Pat. No. 5,423,811 to Imran et al.; U.S. Pat. No. 5,505,730 to Edwards; U.S. Pat. No. 5,545,161 to Imran et al.; U.S. Pat. No. 5,558,672 to Edwards et al.; U.S. Pat. No. 5,569,241 to Edwards; U.S. Pat. No. 5,575,788 to Baker et al.; U.S. Pat. No. 5,658,278 to Imran et al.; U.S. Pat. No. 5,688,267 to Panescu et al.; U.S. Pat. No. 5,697,927 to Imran et al.; U.S. Pat. No. 5,722,403 to McGee et al.; U.S. Pat. No. 5,769,846; and PCT Patent Application Publication No. WO 97/32525 to Pomeranz et al.; and PCT Patent Application Publication No. WO 98/02201 to Pomeranz et al.
Cardiac Arrhythmias
Cardiac arrhythmias, and atrial fibrillation in particular, persist as common and dangerous medical ailments and are particularly prevalent among the aging population. A patient with cardiac arrhythmia has abnormal regions of cardiac tissue that do not follow the synchronous beating cycle associated with normally conductive tissue. Instead, the abnormal regions of cardiac tissue conduct aberrant signals to adjacent tissue, thereby disrupting the cardiac cycle and producing an asynchronous cardiac rhythm. Such abnormal conduction has been previously known to occur at various regions of the heart, such as, for example, in the region of the sino-atrial (SA) node, along the conduction pathways of the atrioventricular (AV) node and the Bundle of His, or in the cardiac muscle tissue forming the walls of the ventricular and atrial cardiac chambers.
Cardiac arrhythmias, including atrial arrhythmia, may be of a multiwavelet reentrant type, characterized by multiple asynchronous loops of electrical impulses that are scattered about the atrial chamber and are often self-propagating. In the alternative or in addition to the multiwavelet reentrant type, cardiac arrhythmias may also have a focal origin, such as when an isolated region of tissue in an atrium fires autonomously in a rapid, repetitive fashion. Cardiac arrhythmias, including atrial fibrillation, may be generally detected using the global technique of an electrocardiogram (EKG). More sensitive procedures of mapping the specific conduction along the cardiac chambers have also been disclosed, such as, for example, in U.S. Pat. No. 4,641,649 to Walinsky et al. and Published PCT Patent Application No. WO 96/32897 to Desai.
A host of clinical conditions may result from the irregular cardiac function and resulting hemodynamic abnormalities associated with atrial fibrillation, including stroke, heart failure, and other thromboembolic events. In fact, atrial fibrillation is believed to be a significant cause of cerebral stroke, wherein the abnormal hemodynamics in the left atrium caused by the fibrillatory wall motion precipitate the formation of thrombus within the atrial chamber. A thromboembolism is ultimately dislodged into the left ventricle which thereafter pumps the embolism into the cerebral circulation where a stroke results. Accordingly, numerous procedures for treating atrial arrhythmias have been developed, including pharmacological, surgical, and catheter ablation procedures.
Several pharmacological approaches intended to remedy or otherwise treat atrial arrhythmias have been disclosed, such as for example according to the disclosures of the following references: U.S. Pat. No. 4,673,563 to Berne et al.; U.S. Pat. No. 4,569,801 to Molloy et al.; and also xe2x80x9cCurrent Management of Arrhythmiasxe2x80x9d (1991) by Hindricks, et al. However, such pharmacological solutions are not generally believed to be entirely effective in many cases, and are even believed in some cases to result in proarrhythmia and long term inefficacy.
Several surgical approaches have also been developed with the intention of treating atrial fibrillation. One particular example is known as the xe2x80x9cmaze procedure,xe2x80x9d as is disclosed by Cox, J L et al. in xe2x80x9cThe surgical treatment of atrial fibrillation. I. Summaryxe2x80x9d Thoracic and Cardiovascular Surgery 101(3), pp. 402-405 (1991); and also by Cox, J L in xe2x80x9cThe surgical treatment of atrial fibrillation. IV. Surgical Techniquexe2x80x9d, Thoracic and Cardiovascular Surgery 101(4), pp. 584-592 (1991). In general, the xe2x80x9cmazexe2x80x9d procedure is designed to relieve atrial arrhythmia by restoring effective atrial systole and sinus node control through a prescribed pattern of incisions about the tissue wall. In the early clinical experiences reported, the xe2x80x9cmazexe2x80x9d procedure included surgical incisions in both the right and the left atrial chambers. However, more recent reports predict that the surgical xe2x80x9cmazexe2x80x9d procedure may be substantially efficacious when performed only in the left atrium, such as is disclosed in Sueda et al., xe2x80x9cSimple Left Atrial Procedure for Chronic Atrial Fibrillation Associated With Mitral Valve Diseasexe2x80x9d (1996).
The xe2x80x9cmaze procedurexe2x80x9d as performed in the left atrium generally includes forming vertical incisions from the two superior pulmonary veins and terminating in the region of the mitral valve annulus, traversing the region of the inferior pulmonary veins en route. An additional horizontal line also connects the superior ends of the two vertical incisions. Thus, the atrial wall region bordered by the pulmonary vein ostia is isolated from the other atrial tissue. In this process, the mechanical sectioning of atrial tissue eliminates the arrhythmogenic conduction from the boxed region of the pulmonary veins and to the rest of the atrium by creating conduction blocks within the aberrant electrical conduction pathways. Other variations or modifications of this specific pattern just described have also been disclosed, all sharing the primary purpose of isolating known or suspected regions of arrhythmogenic origin or propagation along the atrial wall.
While the xe2x80x9cmazexe2x80x9d procedure and its variations as reported by Cox and others have met some success in treating patients with atrial arrhythmia, its highly invasive methodology is believed to be prohibitive in most cases. However, these procedures have provided a guiding principle that electrically isolating faulty cardiac tissue may successfully prevent atrial arrhythmia, and particularly atrial fibrillation caused by arrhythmogenic conduction arising from the region of the pulmonary veins.
Less invasive catheter-based approaches to treat atrial fibrillation have been disclosed which implement cardiac tissue ablation for terminating arrhythmogenic conduction in the atria. Examples of such catheter-based devices and treatment methods have generally targeted atrial segmentation with ablation catheter devices and methods adapted to form linear or curvilinear lesions in the wall tissue which defines the atrial chambers. Some specifically disclosed approaches provide ablation elements that are linear over a defined length and are intended to engage the tissue for creating the linear lesion. Other disclosed approaches provide shaped or steerable guiding sheaths, or sheaths within sheaths, for the intended purpose of directing tip ablation catheters toward the posterior left atrial wall such that sequential ablations along the predetermined path of tissue may create the desired lesion. In addition, various energy delivery modalities have been disclosed for forming atrial wall lesions, and include use of microwave, laser, ultrasound, thermal conduction, and more commonly, radiofrequency energies to create conduction blocks along the cardiac tissue wall.
Further more detailed examples of ablation device assemblies and methods for creating lesions along an atrial wall are disclosed in the following U.S. patent references: U.S. Pat. No. 4,898,591 to Jang et al.; U.S. Pat. No. 5,104,393 to Isner et al.; U.S. Pat. No. 5,427,119; U.S. Pat. No. 5,487,385 to Avitall; U.S. Pat. No. 5,545,193 to Fleischman et al.; U.S. Pat. No. 5,549,661 to Kordis et al.; U.S. Pat. No. 5,575,810 to Swanson et al.; U.S. Pat. No. 5,564,440 to Swartz et al.; U.S. Pat. No. 5,575,766 to Swartz et al.; U.S. Pat. No. 5,582,609 to Swanson; U.S. Pat. No. 5,617,854 to Munsif; U.S. Pat. No. 5,687,723 to Avitall; U.S. Pat. No. 5,702,438 to Avitall.
Other examples of such ablation devices and methods are disclosed in the following Published PCT Patent Applications: WO 93/20767 to Stem et al.; WO 94/21165 to Kordis et al.; WO 96/10961 to Fleischman et al.; WO 96/26675 to Klein et al.; and WO 97/37607 to Schaer.
Additional examples of such ablation devices and methods are disclosed in the following published articles: xe2x80x9cPhysics and Engineering of Transcatheter Tissue Ablationxe2x80x9d, Avitall et al., Journal of American College of Cardiology, Volume 22, No. 3:921-932 (1993); and xe2x80x9cRight and Left Atrial Radiofrequency Catheter Therapy of Paroxysmal Atrial Fibrillation,xe2x80x9d Haissaguerre, et al., Journal of Cardiovascular Electrophysiology 7(12), pp. 1132-1144 (1996).
In addition to the known assemblies summarized above, additional tissue ablation device assemblies have also been recently developed for the specific purpose of ensuring firm contact and consistent positioning of a linear ablation element along a length of tissue. These assemblies anchor the element at one or more predetermined locations along the length of tissue, such as in order to form a xe2x80x9cmazexe2x80x9d-type lesion pattern in the left atrium. One example assembly includes an anchor at each of two ends of a linear ablation element. The anchors are used to secure the ends to each of two predetermined locations along a left atrial wall, such as at two adjacent pulmonary veins, so that tissue may be ablated along the length of tissue extending therebetween.
In addition to attempting atrial wall segmentation with long linear lesions for treating atrial arrhythmia, other ablation devices and methods have also been disclosed which are intended to use expandable members such as balloons to ablate cardiac tissue. Some such devices have been disclosed primarily for use in ablating tissue wall regions along the cardiac chambers. Other devices and methods have been disclosed for treating abnormal conduction of the left-sided accessory pathways, and in particular associated with xe2x80x9cWolff-Parkinson-Whitexe2x80x9d syndromexe2x80x94various such disclosures use a balloon for ablating from within a region of an associated coronary sinus adjacent to the desired cardiac tissue to ablate. Further more detailed examples of devices and methods such as of the types just described are variously disclosed in the following published references: Fram et al., in xe2x80x9cFeasibility of RF Powered Thermal Balloon Ablation of Atrioventricular Bypass Tracts via the Coronary Sinus: In vivo Canine Studies,xe2x80x9d PACE, Vol. 18, p 1518-1530 (1995); xe2x80x9cLong-term effects of percutaneous laser balloon ablation from the canine coronary sinusxe2x80x9d, Schuger C D et al., Circulation (1992) 86:947-954; and xe2x80x9cPercutaneous laser balloon coagulation of accessory pathwaysxe2x80x9d, McMath L P et al., Diagn Ther Cardiovasc Interven 1991; 1425:165-171.
Cardiac Arrhythmias Originating from Foci in Pulmonary Veins
As discussed above, some modes of atrial fibrillation are focal in nature, caused by the rapid and repetitive firing of an isolated center within cardiac muscle tissue associated with the atrium. Such foci may act as either a trigger of atrial fibrillatory paroxysmal or may even sustain the fibrillation. Various disclosures have suggested that focal atrial arrhythmia often originates from at least one tissue region along one or more of the pulmonary veins of the left atrium, and even more particularly in the superior pulmonary veins.
Less-invasive percutaneous catheter ablation techniques have been disclosed which use end-electrode catheter designs with the intention of ablating and thereby treating focal arrhythmias in the pulmonary veins. These ablation procedures are typically characterized by the incremental application of electrical energy to the tissue to form focal lesions designed to terminate the inappropriate arrhythmogenic conduction.
One example of a focal ablation method intended to treat focal arrhythmia originating from a pulmonary vein is disclosed by Haissaguerre, et al. in xe2x80x9cRight and Left Atrial Radiofrequency Catheter Therapy of Paroxysmal Atrial Fibrillationxe2x80x9d in Journal of Cardiovascular Electrophysiology 7(12), pp. 1132-1144 (1996). Haissaguerre, et al. discloses radiofrequency catheter ablation of drug-refractory paroxysmal atrial fibrillation using linear atrial lesions complemented by focal ablation targeted at arrhythmogenic foci in a screened patient population. The site of the arrhythmogenic foci were generally located just inside the superior pulmonary vein, and the focal ablations were generally performed using a standard 4 mm tip single ablation electrode.
Another focal ablation method of treating atrial arrhythmias is disclosed in Jais et al., xe2x80x9cA focal source of atrial fibrillation treated by discrete radiofrequency ablation,xe2x80x9d Circulation 95:572-576 (1997). Jais et al. discloses treating patients with paroxysmal arrhythmias originating from a focal source by ablating that source. At the site of arrhythmogenic tissue, in both right and left atria, several pulses of a discrete source of radiofrequency energy were applied in order to eliminate the fibrillatory process.
Other assemblies and methods have been disclosed addressing focal sources of arrhythmia in pulmonary veins by ablating circumferential regions of tissue either along the pulmonary vein, at the ostium of the vein along the atrial wall, or encircling the ostium and along the atrial wall. More detailed examples of device assemblies and methods for treating focal arrhythmia as just described are disclosed the following references: U.S. Pat. No. 6,117,101 to Diederich et al.; U.S. Pat. No. 6,024,740 to Lesh et al.; U.S. Pat. No. 6,012,457 to Lesh; U.S. Pat. No. 6,305,378 to Lesh; and U.S. Ser. Nos. 09/642,251 entitled xe2x80x9cDevice and Method for Forming a Circumferential Conduction Block in a Pulmonary Veinxe2x80x9d to Michael D. Lesh. The disclosures of these references are herein incorporated in their entirety by reference thereto.
Another specific device assembly and method which is intended to treat focal atrial fibrillation by ablating a circumferential region of tissue between two seals in order to form a conduction block to isolate an arrhythmogenic focus within a pulmonary vein is disclosed in U.S. Pat. No. 5,938,660 to Swartz et al. and a related Published PCT Patent Application No. WO 99/00064.
In particular, certain tissue ablation device assemblies that incorporate ultrasound energy sources have been observed to be highly efficient and effective for ablating circumferential regions of tissue where pulmonary veins extend from atria. However, the efficiency of ultrasonic output from such a source has been observed to be directly related to the structural coupling of the transducer to the underlying delivery member or catheter shaft. The transducer output is damped whenever it is in contact with any sort of mounting means between the back or inner side of the transducer and the catheter shaft, even according to known modes using elastomeric mounting structures sandwiched between the transducer and the shaft. Several known ultrasound transducer mounting examples provide support structures that extend between the transducer and the underlying support member, such that for example the transducer rests on the support member which rests on the delivery member. Further more detailed examples of such ultrasound transducer support structures are disclosed in the following references: U.S. Pat. No. 5,606,974 to Castellano; and U.S. Pat. No. 5,620,479 to Diederich. Further examples of structural support designs for ultrasound transducers on catheter shafts are disclosed in published PCT Patent Application PCT/US98/09554 (WO98/49957) to Diederich et al.
Further to the previously disclosed ultrasound transducer mounting structures and arrangements, it is desirable for the mounting structure to provide sufficient support and positioning for the transducer. It is also desirable that such a mounting structure provides for air backing between the transducer and the underlying delivery shaft in order to isolate ultrasound transmission radially away from the catheter shaft and toward tissue surrounding the shaft. It has been observed that such air backing helps prevent heat build-up in the region, as the vibrational ultrasound energy has been observed to superheat other materials in contact therewith which absorb the energy (airbacking actually reflects the energy radially outwardly as desired). Therefore, such air backing is particularly desirable for high operational powers associated with therapeutic ultrasound ablation transmission. It is also desirable that such a mounting structure adequately supports the transducer while minimizing the vibrational damping of the transducer during operation. The present invention addresses these desires.
The present invention provides various improved catheter constructions and associated methods of manufacture for mounting an ultrasound transducer onto a catheter shaft while minimizing the damping of the transducer associated with the structural coupling. In several of the construction variations, the transducer is suspended about an inner member (e.g., the catheter body) absent any support structure between the catheter and the transducer along the length of the transducer. That is, transducer mounting is accomplished without the use of internal mounting members and/or elastic member in the space between the inner member and the transducer. Such mounting arrangements support the transducer and are attached to the inner member (or to an assembly of members) at points proximal and distal of the ultrasound transducer.
In one mode of the present invention, an ultrasound ablation apparatus is provided with reduced transducer damping. The apparatus comprises an elongate catheter body having proximal and distal end portions, an outer wall and an outer diameter; a cylindrical ultrasound transducer coaxially disposed over the catheter body, the ultrasound transducer having proximal and distal end portions, an inner wall and an inner diameter which is greater than the outer diameter of the catheter body. Consequently, an air gap is provided in a radial separation between the inner wall of the ultrasound transducer and the catheter body. The apparatus also includes a support structure for suspending the ultrasound transducer in a substantially fixed coaxial position relative to the catheter body. The support structure contacts the outer wall of the catheter body at locations proximal and distal to the proximal and distal end portions of the ultrasound transducer, respectively. Accordingly, the support structure holds the ultrasound transducer without contacting the inner wall of the ultrasound transducer, thereby maintaining the radial separation while reducing transducer damping.
In one preferred mode of the ultrasound ablation apparatus, the ultrasound transducer is shaped to ablate a circumferential region of tissue. The transducer may include at least one transmissive panel.
In another aspect of the ultrasound ablation apparatus, at least a substantial portion of the radial separation is sealed by the support structure to prevent external fluids from entering the radial separation. A gas may be sealed within the radial separation. Alternatively, a liquid maybe sealed within the radial separation.
The ultrasound ablation apparatus of the present invention may include first and second flanges extending axially from the proximal and distal end portions of the ultrasound transducer, respectively, the support structure being coupled to the first and second flanges. The support structure may comprise first and second elastomeric O-rings disposed on the catheter body such that the first and second O-rings engage the first and second flanges. In a variation of this mode, the support structure may comprises first and second sleeves disposed on the catheter body and fitted over the first and second flanges, to secure the ultrasound transducer relative to the catheter body. In another variation, the support structure may comprise first and second splines disposed on the catheter body such that the first and second splines engage the first and second flanges. Alternatively, the support structure may comprise first and second annular members disposed along the catheter body such that the first and second annular members engage the first and second flanges.
In another aspect of the present invention, the support structure may comprise first and second annular members disposed on the catheter body, wherein the first and second annular members frictionally engage the proximal and distal end portions of the ultrasound transducer. The support structure could also comprise a shrink-wrap cover layer disposed around the ultrasound transducer.
In one preferred embodiment, the ultrasound ablation apparatus of the present invention may include an expandable member adapted to engage a circumferential region of tissue. In this mode, the ultrasound transducer is located inside the expandable member and acoustically coupled to the expandable member. The expandable member may be an inflatable balloon.
In a variation to the expandable member embodiment, the ultrasound ablation apparatus may also have a cooling chamber between the ultrasound transducer and the expandable member. The cooling chamber is adapted to allow a cooling fluid to flow over said ultrasound transducer. Further, this mode may include a source of pressurized cooling fluid and a cooling fluid lumen in the catheter body. The lumen may have a distal port opening into the cooling chamber. The ultrasound ablation apparatus may also incorporate a thermocouple for monitoring temperature along at least a portion of the circumferential region of tissue engaged by the expandable member.
The ultrasound ablation apparatus of the present invention may also include at least one electrical lead coupled to the ultrasound transducer.
In a variation of the mounting structure, the apparatus may comprise fillets located proximal and distal to proximal and distal end portions of the ultrasound transducer for sealing the radial separation from entry of external fluids and providing a smooth surface for insertion of said ultrasound ablation apparatus into a body structure.
In another variation, the ultrasound ablation apparatus may include a guidewire lumen extending through at least a portion of the catheter body for slidably engaging a guidewire.
In another variation to the present invention, the appartus may comprise an elongate catheter body; and an cylindrical ultrasound transducer having first and second ends and inner and outer surfaces. The ultrasound transducer is mounted coaxially on the catheter body such that a radial separation is provided between the ultrasound transducer and the catheter body for mechanically isolating the ultrasound transducer from the catheter body. In this mode, the support structure is coupled to the ultrasound transducer and the catheter body to maintain at least a region of the radial separation for reducing acoustic damping caused by the support structure.
In variations to this mode, annular end members may be provided with a metallic exterior surface adapted to engage the inner surface of the ablation element. This mounting mode may also include an annular intermediate portion, located between the first and second annular members and the catheter body.
In another variation, the support structure may comprise a substantially tubular member disposed over the catheter body. The tubular member has proximal and distal end regions and an intermediate region. The proximal and distal end regions are formed with a larger diameter than the intermediate region. The ultrasound transducer is disposed over the intermediate region such that it is axially contained by the proximal and distal end regions.
In another variation, the support structure may comprise at least one mandrel extending axially along the catheter body The at least one mandrel engages the catheter body and the inner surface of the ultrasound ablation element. The at least one mandrel may be a polyimide tube. More preferably, the at least one mandrel comprises a plurality of polyimide tubes positioned substantially uniformly around the catheter body within the radial separation.
In another variation, the support structure may comprise a braided metal tubular member disposed around the catheter body such that the radial separation is maintained therebetween. The ultrasound transducer is mounted coaxially over the braided tubular member. Alternatively, the support structure may include two braided metal tubular members disposed around the catheter body with an axial gap therebetween. The ultrasound transducer may be mounted to the braided tubular members thereby bridging the axial gap.
In another aspect of the invention, the support structure may comprise two truncated conical members, each having a first end with a large diameter and a second end with a small diameter. The conical members are disposed over the catheter body such that the first ends face inward and the second ends face outward. The inner surface of the ultrasound transducer is engaged by the first ends of the conical members.
In accordance with another mode of the invention, the support structure may comprise an expandable member disposed over the catheter body and having an outer surface. The inner surface of the ultrasound transducer may then be coaxially engaged by the outer surface of the expandable member.
The modes of the invention are generally adapted to capture air, or another gas as would be apparent to one of ordinary skill, within the mounting structures in order to xe2x80x9cair backxe2x80x9d the transducer. That is, these modes of suspension maintain an air gap between the transducer and the catheter shaft in order to maximize radially outward propagation of the ultrasound waves, as introduced above. In addition, the air space desirably is sealed to prevent fluid infiltration, be it blood or another fluid.
According to further beneficial modes, the ultrasound transducer apparatus and method modes just summarized are applied in a circumferential ablation device assembly which is adapted to couple to and ablate a circumferential region of tissue at a location where a pulmonary vein extends from an atrium. Moreover, the modes described for use with a circumferential ultrasound transducer may also be adapted for use with non-circumferential types of transducers, such as incorporating panel transducers that also benefit by being air backed without mounting members physically located and extending between such transducers and an underlying catheter shaft.
For purposes of summarizing the invention and the advantages achieved over the prior art, certain objects and advantages of the invention have been described above and are described below. Of course, it is to be understood that not necessarily all such objects or advantages may be achieved in accordance with any particular mode of the invention. Thus, for example, those skilled in the art will recognize that the invention may be embodied or carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other objects or advantages as may be taught or suggested herein.
All of these embodiments are intended to be within the scope of the invention herein disclosed. These and other embodiments of the present invention will become readily apparent to those skilled in the art from the following detailed description of the preferred embodiments having reference to the attached figures, the invention not being limited to any particular preferred embodiment(s) disclosed. In addition, further aspects, advantages and features of the invention will become apparent from the following descriptions of the preferred modes of incorporating an ultrasound transducer onto a delivery element.
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Telecommunication networks provide for the transmission of information across some distance through terrestrial, wireless or satellite communication networks. Such communications may involve voice, data or multimedia information, among others. In addition, telecommunication networks often offer features and/or services to the customers of the network that provide flexible and varied ways in which the communications are transmitted over the network. For example, some telecommunication networks provide a conferencing feature that allows several users of the network to communicate at once, rather than a simple person-to-person communication. The number of participants to a conference communication may range from several users to several thousand users communicating on the same telephonic, video and/or data call.
In many instances, the collaboration conference system includes systems and/or components from several different systems. For example, a first network or system may provide a voice component of the collaboration conference while a second network or system may provide an online component of the collaboration. However, because multiple systems may be incorporated or used for a collaboration conference, troubleshooting of issues that arise during the collaboration conference may be difficult as a single administrator may not have access to each component within the multiple systems. Thus, receiving an indication of a connectivity issue or other problem within the collaboration conference system and executing a solution to the detected problem may require extensive communication and sharing of remedies between the various operators of the varying systems of the collaboration conference. Such collaboration may be both time and workforce intensive.
It is with these and other issues in mind that various aspects of the present disclosure were developed.
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This application is based on and claims the priority under 35 U.S.C. xc2xa7119 of German Patent Application 100 00 915.8, filed on Jan. 12, 2000, the entire disclosure of which is incorporated. herein by reference.
The invention relates to a brake for a vehicle and particularly an aircraft, but also a land vehicle, including at least one stator brake disk that is fixed to a rotatable wheel axle, and at least one rotor brake disk that is rotatable relative to the wheel axle and arranged parallel to the stator brake disk. The stator brake disk includes a brake lining or brake pad arranged circumferentially around a supporting ring that is mechanically secured to the wheel axle.
In the field of aircraft construction, it is conventionally known to use hydraulically actuated multi-disk brakes for the landing gear wheels, especially of larger aircraft such as commercial transport aircraft. Such multi-disk brakes include stator disks and rotor disks that are arranged or stacked alternately and parallel to each other to form a brake disk packet. The disks of conventional aircraft brakes are generally made essentially of stainless steel (SST) or carbon fiber-reinforced synthetic composites (CFC). Due to the reduced weight and higher braking power capacity, the brake disks of almost all known military and civil aircraft types of modern construction consist of carbon fiber reinforced composites (CFC). Such CFC aircraft brakes, however, suffer the disadvantage of a high replacement cost, while SST brakes have a relatively short operating life (in comparison to CFC brakes), due to the high loads and resultant wear occurring during the braking of large aircraft.
A typical aircraft brake using CFC material for both the stator and rotor disks is characterized by a lower total weight and a higher braking load capacity in comparison to aircraft brakes of SST material. The CFC brake also avoids the use of an actual brake pad or brake lining per se, because the braking effect is achieved by means of a so-called disk/disk pair.
On the other hand, a typical aircraft brake using SST material is constructed as a multi-disk brake packet including stator disks and rotor disks arranged alternately in sequence one after another on the wheel axis, and received between an end disk (or backing disk) and a pressure disk (or pressure plate). The end disk is located on the side of a counter support bearing, which presses or braces against a support member that is rigidly mounted on the wheel axis and, for example, rigidly screwed to the landing gear strut or the like of the aircraft landing gear. The pressure disk, on the other hand, is located on the side of a braking piston housing which is screwed to the support on the wheel axis. A braking piston received in the braking piston housing selectively exerts a braking force onto the pressure disk in a direction toward the counter bearing, so as to press the alternately stacked discs into frictional contact with each other.
The brake linings or pads, which are subjected to extreme loads and resultant high wear due to the braking process, are rather difficult to replace, i.e. exchange, after they have been worn beyond an acceptable limit. Namely, a complete disassembling of the brake arrangement is practically always required when it is necessary to exchange the brake linings or pads. Since the brake pads are secured to the brake disk or rotor support ring by rivets, these rivet connections must be bored out or otherwise broken or released in order to exchange the used brake pads with new brake pads. Then the new brake pads are once again riveted onto the associated support ring. Then, the rest of the previously disassembled brake arrangement must be reassembled. As can be appreciated, this is a very time consuming and costly process. Also, the support ring can suffer wear or damage as a result of repeated removal of old rivets and re-setting of new rivets. The overall maintenance cost and effort is quite considerable for aircraft using such brakes, because such civil aircraft operated by commercial airlines have rather strictly limited time frames prescribed for the maintenance and replacement of the brakes and particularly the brake pads.
The German Patent Publication DE 197 11 829 C1 discloses a method of manufacturing a fiber-reinforced composite ceramic material with high-temperature high-strength fibers on the basis of silicon, carbon, boron, nitrogen or compounds thereof, which are reaction bonded with a matrix of silicon or silicon alloys or compounds. Such fiber-reinforced composite ceramic materials are also usable for manufacturing brake disks in a simple and economical manner. Other ceramic materials are also generally known in the art. For example, a fiber-reinforced ceramic with an oxide system, for example Nextel(trademark), fibers of the 3M Company, based on alumina with an oxide matrix, such as mullite for example, or in combination with a carbide matrix, such as silicon carbide for example, are generally known in the art.
Without further going into the details, there is no known reference in the relevant trade literature, that makes a suggestion to use brake pads made of the above mentioned materials in the above mentioned manner for vehicle brakes and particularly aircraft brakes. The trade literature further gives no hints or suggestions toward the particular localized use of at least one of such brake disks as a stator or a rotor within a multi-disk brake packet of an aircraft brake.
In the field of aircraft construction, there has been a constant effort to achieve landing gear wheel brakes having a relatively low weight, a relatively high braking power capacity, an economical fabrication, and relatively low expected maintenance and replacement part costs, in comparison to prior conventional aircraft brakes. Mostly due to these constant efforts to achieve these advantages in combination, there has never been achieved or suggested a multi-disk brake with alternating disks of different materials, and particularly using a fiber reinforced ceramic for one of the two brake disks that will come into contact with each other, in view of the braking properties and the unavoidable wear of the effective brake surfaces of such a vehicle brake.
In view of the above, it is an object of the invention to provide a vehicle brake arrangement having a low total weight and a high braking power capacity, and which utilizes brake disks that achieve a simple and economical maintenance with a simple and quick exchange of the brake linings or pads, in comparison to prior art brake arrangements. The invention further aims to avoid or overcome the disadvantages of the prior art, and to achieve additional advantages, as apparent from the present specification.
The above objects have been achieved according to the invention in a vehicle brake arrangement including a rotatable wheel axle, and a brake disk stack or packet that includes at least one stat or brake disk secured on the wheel axle, and at least one rotor brake disk that is rotatably supported relative to the wheel axle and is arranged parallel to the stator brake disk. The stator brake disk includes a support arrangement that is mechanically connected to the wheel axle and a brake pad arrangement secured to the support arrangement. The support arrangement includes a support ring and a plurality of support members or support arms that protrude substantially radially from the outer circumference of the support ring and are circumferentially spaced apart from one another. The brake pad or lining arrangement includes a plurality of plate-shaped brake segments that are respectively removably and exchangeably arranged between respective neighboring ones of the support arms.
Throughout this specification, the term xe2x80x9cplate-shapedxe2x80x9d is intended to designate a shape of a member that extends along a plan and that is significantly larger in two dimensions along that plane than in a thickness dimension perpendicular to that plane. Throughout this specification, the terms xe2x80x9cradialxe2x80x9d, xe2x80x9ccircumferentialxe2x80x9d, xe2x80x9caxialxe2x80x9d and the like are to be understood with respect to the rotation axis of the rotating set of brake discs, unless otherwise stated or apparent from a particular context.
The above objects have further been achieved according to the invention in a vehicle brake arrangement including at least one stator brake disk and at least one rotor brake disk as generally described above, whereby the stator brake disk includes a support arrangement and a brake pad arrangement secured thereon. The brake pad arrangement includes a plurality of brake segment pads made of a sintered metal material and adhered onto a plate-shaped brake segment carrier, whereby the brake segment carrier and brake segment pad together form a respective brake segment which is removably and exchangeably arranged on the support arrangement. The rotor brake disk is made of a ceramic material. By selectively bringing the rotor brake disk into contact with the brake segment pad of the stator brake disk, the resulting friction provides the desired braking effect.
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Until now, in the cultivation of agricultural and horticultural crops, although a large number of disease control agents are used against crop disease, since the control effects thereof may be inadequate, the use thereof may be restricted due to the appearance of agrichemical-resistance pathogenic organisms, the plants may be damaged or contaminated by the agrichemical or the agrichemical may demonstrate toxicity to humans, livestock or marine life, a considerable number of these disease control agents are not necessarily considered to be satisfactory. Thus, there is a need to develop a plant disease control agent that can be used safely and has few of these shortcomings.
The present inventors carried out exhaustive research in view of the above-described circumstances, and discovered that tetrazoyloxime derivative and/or the salt thereof are useful as an active ingredient of plant disease control agent, and previously filed a patent application (Patent Document 1).
[Patent Document 1] International Publication No. WO03/016303
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The signaling circuit of a telephone station has traditionally been locked by a mechanical device. Rotary dial telephones are often locked by connecting a cylinder to a finger hole in the rotary dial. A key is then inserted in the cylinder to unlock and remove the cylinder from the rotary dial. Pushbutton telephones are often locked by connecting a cover over the pushbutton keypad. A key is then inserted in the cover to unlock it and remove it from the keypad.
Computer controlled locking arrangements have also been used. With such an arrangement a computer controlled telephone central office or other switching system uses class of service restrictions to lock the signaling circuit of a connected telephone. Computer controlled restriction arrangements are also used to prevent computer terminals from accessing unauthorized programs and data. Under such an arrangement passwords, access codes or identification numbers are assigned to the terminals of their users and the proper password, access code or identification number must be transmitted to the connected computer before the terminal can access restricted programs or data. However, these computer controlled locking or restriction arrangements require administration of class of service codes, passwords, access codes or identification numbers by a central computer and they do not inhibit operation of the telephone or computer terminal.
The present invention overcomes this requirement through use of a locking circuit located within the telephone station.
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Electric power systems have multiple generation units that operate in synchronism under a normal operation. That is, frequency, phase, and amplitude of voltages at the terminals of a generator hold a fixed relationship with the same parameters of the remaining generators in the power system. Before a generator can be connected to an electric power system, the frequency, phase, and amplitude of the voltages at its bus need to be matched with those of the power system at the point of interconnection. Once, the so called synchronization parameters are matched within a desired tolerance, the generator breaker is closed. Any mismatch in the synchronization parameters during connection of a generation unit by a generator breaker may result in undesired transients and disruption of the system.
Traditional synchronization methods for two grid systems is calculating and adapting reference values of the governor and excitation systems. From the frequency deviation and phase angle difference points of view, the total synchronization time is largely depending on the primary and secondary controller of the generator. For a large scale generation system, synchronous machine based power generations, can take several minutes for the grid to finish the synchronization process. However, with the fast development of renewable energy generations, the entire gird is becoming more distributed. Due to the fact that the distributed grid is vulnerable than synchronous machine based grid system, the synchronization method purely relying on the primary and secondary controller is not feasible.
Therefore, the fast synchronization is desired to improve the robustness of the modern power systems. For example, U.S. Pat. No. 7,915,868 B1 disclosed a method of reducing the time to synchronize a turbomachine generator with the electrical grid system. The present disclosure is focused on the design of voltage synchronization during the start-up process of the synchronous machine, among other things. However, the phase and frequency synchronization is more critical than voltage synchronization and not addressed appropriately.
Therefore, there is a need to develop more effective way to achieve fast synchronization with the help of battery systems.
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Xanthomegnin was originally reported to be isolated from several species of each of the genera Penicillium, Aspergillus and Trichophyton. Isolation of xanthomegnin from Trichophyton rubrum was reported by J. C. Wirth et. al., Phytochemistry, 1965, Vol. 4, pp 505-509 and from T. meznini as reported by G. Just et al., Can. J. Chem., 41, 74, 1963. The present invention describes the production of xanthomegnin from a species of fungus of the genus Fusarium. Organisms of this genus have not been previously known to produce xanthomegnin. Xanthomegnin has been determined by G. Just et al. to have the chemical structure of Formula I: ##STR1## It may also be identified by the chemical name (-)3,3'-bis[2-methoxy-5-hydroxy-7-(2-hydroxypropyl)-8-carboxy-1, 4-naphthoquinone lactone].
Xanthomegnin has been shown to have limited antibacterial activity (Boutibonnes, O. et al, Mycopathologia, 87 (1-2), 43 49, 1984). Xanthomegnin has also been tested with minimal success, as an antitumor agent (Kawai, K., et al, Res. Commun. Chem. Pathol. Pharmacol., 36(3), 429-438, 1982). This experiment demonstrated that xanthomegnin had growth inhibitory effects in vitro against certain tumor cells. However, when xanthomegnin was administered intraperitoneally to mice bearing tumor cells, no tumor growth inhibition was seen. Due to the lack of success in the use of xanthomegnin as an antibacterial or antitumor agent, investigation of xanthomegnins' biological properties diminished.
According to the present invention, xanthomegnin has been discovered to have potent parasiticidal, anthelminthic, and insecticidal activity against organisms which affect human and animal health.
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The current global emphasis on environmental protection and pollution abatement has fostered the development of a number of new technologies and processes focused on pollution control in the power production industry. Some of these new technologies represent significant improvements over the previous technologies in the areas of increased pollutant removal efficiencies, reduced reagent requirements, reduced waste streams and reduced operating costs.
One such system is comprised of a selective catalytic reduction (SCR) for the control of nitrogen oxides (NO.sub.x) and sulfuric acid production for sulfur oxide (SO.sub.2) removal. This system results in high efficiency NO.sub.x and SO.sub.2 removal, minimal particulate emissions and no liquid or solid waste production. The system basically begins with some sort of particulate removal apparatus such as an electrostatic precipitator or appropriate filtering equipment. This is followed by a NO.sub.x reduction system which involves the selective catalytic reduction of the NO.sub.x to molecular nitrogen and water by reaction with ammonia (NH.sub.3) and oxygen. Following the selective catalytic reduction of the NO.sub.x, the process catalytically converts sulfur dioxide (SO.sub.2) to sulfur trioxide (SO.sub.3). The SO.sub.3 -containing flue gas stream is then cooled in a wet sulfuric acid condenser, by heat exchange with an air stream, to produce a concentrated sulfuric acid by-product stream. The cleaned flue gas is then ready for release to the atmosphere.
This process generates a considerable amount of recoverable heat in several ways. All of the reactions which take place with respect to NO.sub.x and SO.sub.2 removal are exothermic and increase the temperature of the flue gas. These include the reaction of NO.sub.x and NH.sub.3, SO.sub.2 oxidation, SO.sub.3 hydration to form sulfuric acid fume and condensation of the sulfuric acid. These heats of reaction plus any support heat which may have been added are recovered in the wet sulfuric acid condenser by cooling air. This heated air stream has typically been used for combustion air. A small percentage of the hot air has been used for system auxiliaries, such as ammonia evaporation and dilution, any support burner combustion air required and coal milling. However, the amount of air that is required for cooling in the wet sulfuric acid condenser is usually equal to or greater than the amount required for combustion and auxiliary purposes and/or is often at a higher temperature than desired for either the combustion air preheater or the primary air to the coal pulverizers.
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Oral cancer, predominantly oral squamous cell carcinoma (OSCC), is a high impact disease in the oral cavity, affecting more than 34,000 people in the United States each year (American Cancer Society, 2007). Oral cancer is one of the cancers with the worst prognosis, with a 5-year survival rate of 40-50% (Greenlee, R. T. et al., CA Cancer J Clin, 50:7-33 (2000); Parkin, D. M. et al., CA Cancer J Clin, 55:74-108 (2005)). OSCC tumors arise through a series of molecular mutations that lead to uncontrolled cellular growth from hyperplasia to dysplasia to carcinoma in situ followed by invasive carcinoma. Major risk factors for OSCC include tobacco and alcohol consumption along with environmental and genetics factors (Brinkman, B. M. N. and Wong, D. T., Curr Opin Oncol, 18:228-233 (2006); Figuerido, M. L. et al., Drug Discov Today: Dis Mechan, 1:273-281 (2004); Hu, S. et al., Arthritis Rheum., 56:3588-600 (2007); Turhani, D. et al., Electrophor, 27:1417-1423 (2006)). OSCC is usually detected at late stages when the cancer has advanced and therefore results in poor prognosis and survival. Every individual has a unique prognosis due to the aggressiveness of their tumors therefore they do not behave similarly under the TNM staging system, which classifies tumors by size, lymph node metastasis and distant metastasis. Presently, surgery and radiotherapy are the primary treatments, but due to OSCC's location in the head and neck; this usually results in postoperative defects and functional impairments in patients (Thomson, P. J. and Wylie, J., Int J Oral Maxillofac Surg, 31:145-153 (2002)). Therefore, early disease detection is imperative because it can result in a more effective treatment with superior results.
Squamous cell carcinoma (SCC) of the oral cavity and oropharynx is the 6th most common cancer, with approximately 350,000 new cases worldwide annually. The overall 5-year survival rates for oral squamous cell carcinoma (OSCC) have remained low at approximately 30-40% for the past decades. Delayed detection is one of the main reasons for the high morbidity rate of oral cancer, suggesting an imperative need for developing biomarkers to improve early detection of oral cancers. Proteomic analysis of body fluids (e.g., saliva and serum) over the course of oral cancer progression holds promise to identify early detection biomarkers for human oral cancer.
Biomarkers are measurable biological and physiological parameters that can serve as indices for health-related assessments. Protein biomarkers are particularly powerful because they are amenable to simple blood or saliva tests and, once successfully developed, can benefit the cancer patients as simple clinical tools. In terms of identifying protein markers for cancer detection, a body fluid approach (e.g., saliva or blood) appears to be very attractive because it is easy to collect and process these body fluids as compared to tissue biopsies.
Saliva has gained notable attention as a diagnostic fluid because of its simple collection and processing, minimal invasiveness and low costs. Many researchers have studied salivary proteins as potential diagnostic markers for various diseases such as breast cancer, ovarian cancer, Sjögrens syndrome, hepatocellular carcinoma, leukoplakia and oral cancer (Ryu, O. H. et al., Rheumatol, 45:1077-1086 (2006); Streckfus, D. et al., Cancer Invest, 18:101-109 (2000); Rhodus, N. L. et al., Cancer Detect Prev, 29:42-45 (2005); Brailo, V. et al., Oral Oncol, 42(4):370-373 (2006); Yio, X. et al., Ann Clin Biochem, 29:519-522 (1992); Gorelik, E. et al., Cancer Epidemiol Biomarkers Prev, 14:981-987 (2005); Hu, S. et al., Arthritis Rheum., 56:3588-600 (2007)). These potential disease markers, if successfully developed, can lead to simple clinical tools for early detection and the monitoring of disease prognosis and treatment in saliva, a non-invasive body fluid (Kingsmore, S. F., Nat Rev Drug Discov, 5:310-321 (2006)).
Currently there are no reliable saliva biomarkers in the clinic for OSCC, however, some recent studies have suggested signature proteins in saliva from OSCC patients can be used for the disease detection. For instance, salivary proteins such as TNF-alpha, interleukin-1 (IL-1), IL-6, IL-8, CD44, fibronectin, defensin-1, cytokeratin 19 fragment (CYFRA 21-1), tissue polypeptide antigen, and cancer antigen CA125, were found over-expressed in OSCC patients (Mizukawa, N. et al., Oral Dis, 5(2):139-142 (1999); Franzmann, E. J. et al., Cancer Epidemiol Biomarkers Prev, 14(3):735-739 (2005); Rhodus, L. et al., Cancer Detect Prev, 29(1):42-45 (2005); Lyons, A. J. and Cui, N., J Oral Path Med, 29(6):267-270 (2000); Nagler, R. et al., Clin Cancer Res, 12(13):3979-3984 (2006); St. John, M. I. et al., Arch Otolaryngol Head Neck Surg, 130:929-935 (2004); Rhodus, N. L. et al., Cancer Detect Prev, 29(1):42-5 (2005); Brailo, V. et al., Oral Oncol, 42:370-373 (2006)). These proteins, if successfully validated in a large patient cohort, could be potentially useful for OSCC detection.
Analysis of the proteomic content in human saliva is important because it will not only contribute to understanding of oral health and disease pathogenesis but also form a foundation for the discovery of saliva protein biomarkers for human disease detection. Mass spectrometry (MS)-based proteomics has been successfully applied to identification of proteins and their PTMs in human whole and ductal saliva (Wilmarth, P. A. et al., J. Proteome Res., 3(5):1017-1023 (2004); Hu, S. et al., Proteomics, 5(6):1714-1728 (2005); Xie, H. et al., Mol. Cell. Proteomics, 4(11):1826-1830 (2005); Yates, J. R. et al., Anal. Chem., 78(2):493-500 (2006); Guo, T. et al., J. Proteome Res., 5(6):1469-1478 (2006); Hu, S. et al., Ann. N.Y. Acad. Sci, 1098:323-329 (2007)). Many of these studies were performed using shotgun proteomics, which is based on multidimensional separation, tandem MS (MS/MS) and database searching algorithms. Shotgun proteome analysis is very efficient in cataloguing and profiling of proteins, whereas 2-D gel electrophoresis coupled with MS (2-DE/MS) allows mapping out the proteome at protein level and visualization of protein modifications and isoforms (Hirtz, C. et al., Proteomics, 5(17):4597-4607 (2005); Walz, A. et al., Proteomics, 6(5):1631-1639 (2006)).
Profiling of salivary glycoproteins and proteins in distinct families has been demonstrated lately. The selective enrichment of glycoproteins followed by liquid chromatography-tandem MS (LC-MS/MS) profiling may appear to be a promising approach for finding biomarker and therapeutic targets in cancers (Ramachandran, P. et al., J. Proteome Res., 5(6):1493-1503 (2006)). Analysis and characterization of cystatins, histatins, proline-rich proteins and their fragments in saliva provides further insight in assessment of their functions in the oral cavity (Inzitari, R. et al., Proteomics, 6(23):6370-6379 (2006); Inzitari, R. et al., Proteomics, 5(3):805-815 (2005); Messana, I. et al., J. Proteome Res., 3(4):792-800 (2004); Castagnola, M. et al., J. Biol. Chem., 279(40):41436-41443 (2004); Lupi, A. et al., Proteomics, 3(4):461-467 (2003)). In addition, a salivary proteome database (http://www.hspp.ucla.edu) has been established to centralize the acquired proteomic data and annotate the identified saliva proteins. These databases are fully accessible to the public for query of the identified proteins, which are linked to public protein databases. With the data deposited and centralized, the processes of integrating large-scale datasets from a variety of laboratories and conducting comparative analysis of saliva proteome to other body fluid proteomes can now begin.
Early diagnosis of oral cancers is imperative, as successful treatment of these cancers often depends on early detection. Considering that approximately 10% of the general population have oral mucosal abnormalities, and that precancerous and early cancerous lesions rarely demonstrate distinct clinical characteristics, there is a growing realization that some premalignant and early cancerous lesions are not readily detectable by visual inspection. Therefore, the integration of early detection and screening based on protein biomarkers, in conjunction with a conventional oral examination, is extremely important. This clearly requires comparative proteome analysis of oral pre-cancer and cancer samples in order to achieve protein markers for truly early detection of OSCC.
The present invention fulfills a need in the art for both salivary oral cancer protein biomarkers and practical methods of detecting these saliva-based biomarkers. The present invention provides saliva-based diagnostic biomarkers of oral squamous cell carcinoma (OSCC) and periodontal disease. The present invention also provides methods of diagnosing and distinguishing both periodontal disease and OSCC.
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Throughout the years, new features in refrigerators demand cooling, such as ice makers and water chillers have been incorporated into household refrigerators. As these features have evolved in terms of location, size, capacity and efficiency, new ways of providing refrigeration must be developed. Recently, much effort has been spent on cooling these features with cold air stream-based solutions. However, cold air stream-based solutions typically do not provide enough cooling capacity to refrigerator features, whether within the refrigerator or on the door, thus limiting their capacity and performance. Therefore, a need has been identified in the art to provide a secondary cooling loop for cooling features such as ice maker, water chiller, and/or other compartment within the refrigerator on the door.
There also have been considerable efforts recently to maximize the storage space in the fresh food and freezer compartments of a refrigerator. Some of these efforts focus on changing the size and position of the ice maker, either located in the freezer or fresh food compartment, but have limited ice production rates. Therefore, a need has been identified in the art to provide the consumer with the option of adding/removing different size and capacity module ice makers or other features, such as a water chiller, chilled compartment, or the like.
The present invention addresses these needs and other needs in the art to provide secondary cooling within the refrigerator or on the door of the refrigerator.
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{
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In the sewage treatment industry, clarifier tanks are used to remove solid waste from the water. Typical clarifier tanks as shown in FIG. 1, employ a main tank, an agitation device, optional density baffles, and an effluent trough. In use, raw or semi-treated water is pumped into the bottom center of the tank. Density baffles and gravity assist in holding down solids. The cleaner water then spills over into the effluent trough (usually, but not necessarily, located along the upper outer circumference of the tank) and off to further treatment. In order to reduce buildup of algae and other such unwanted contaminants caused by light, a cover is usually disposed over the effluent trough to block sunlight.
However, as shown in FIG. 2, a newer type of clarifier tank, includes a double trough system, whereby a first outer wall trough around the upper circumference is used as an influent trough (instead of a bottom fed tank) and a second attached effluent trough is located inboard of the influent trough for receiving the clarified outgoing water. These two troughs are divided by an upwardly extended dividing wall. In one arrangement, the upwardly extending dividing wall is non-circular, such that the relative widths of the influent and effluent troughs vary with respect to one another.
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Foot-operated throttles are used in many boats, for example, in "Bass Boats," and other types of boats having high performance outboard motors. One approach to design of throttles for this purpose, which was developed some years ago for after-market installation, employed a pedal pivotally mounted on a base, an eccentric, also pivotally mounted on a side of the base, and actuated by the pedal, a receptor mount adjustably attached to the base and a spring biasing the eccentric toward the rear of the receptor mount. The receptor mount included one or more receptors for securing the outer sheath of a throttle-actuating cable, and the eccentric made provision for being connected to the inner, movable member of the cable. Control of maximum gas feed for these throttles was obtained by means of a stop extending upward from the base at its front end and engageable by the bottom of the pedal. No provision was made in these throttles for control of idle speed upon release of the pedal. This function was instead performed by idle speed mechanisms built into the carburetor.
Recent developments in outboard motor technology have made the prior approach to idle speed control obsolete. Outboard motors now include numerous electronic sensors which control complex fuel injection systems, ignition timing and the like. Precise controls over cable positions are now required for idle speed control.
An idle stop mechanism for foot-operated throttles is disclosed in U. S. Pat. No. 5,865,068, issued Feb. 2, 1999. This patent shows a limiter in the form of a bolt adjustably mounted on the receptor mount and aligned to come into contact with a limiter block provided on the eccentric. Installation of throttles having this stop mechanism requires two adjustments between the eccentric and the receptor mount; one for adjustment of the cable to proper position, and the other for positioning the limiter bolt of the idle stop mechanism. It would be desirable to provide for making adjustments to the stop mechanism independent of adjustments to cable position. This would simplify installation of the throttle and allow more flexibility with regard to the types or brands of motors for which the footoperated throttle may be used.
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{
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Imaging devices include cameras provided with an image shake correction device having a shake detection unit and a shake correction unit that corrects image shake caused by camera shake or the like. Such an image shake correction device detects angular shake using an angular velocimeter or the like and reduces image shake on an imaging plane by moving a part of a lens group serving as the shake correction unit or an image sensor.
However, there are cases in photographing performed at a close distance or photographing with high photographic magnifying power in which an image is affected by shake that cannot be detected only with an angular velocimeter. Consequently, image deterioration can arise due to image shake caused by so-called parallel shake that is applied in a direction parallel to the optical axis of a camera or a direction perpendicular thereto. For example, if macro photographing is performed when a camera approaches a subject up to about 20 cm, or if the focal length of an imaging optical system is long (for example, 400 mm) even when the subject is about 1 m away from the camera, it is necessary to actively detect and correct parallel shake.
Patent Literature 1 discloses a technology in which parallel shake is obtained from double integration of acceleration detected by an accelerometer and then a shake correction unit is driven using an output of a separately provided angular velocimeter along therewith. In this case, the output of the accelerometer is affected by an environmental change such as disturbing noise or a temperature change. Since such an instability factor further expands as acceleration undergoes double integration, highly accurate correction of parallel shake is difficult.
Patent Literature 2 discloses a method for obtaining parallel shake by deeming it as angular shake when the center of rotation is assumed to be at a position away from a camera. In this method, an angular velocimeter and an accelerometer are provided, a correction value and an angle are obtained using the rotation radius of the angular shake from outputs of the meters and accordingly shake is corrected, and the center of rotation can be obtained limited to a frequency band in which influence of a disturbance is seldom received. Through the operation described above, the influence of an instability factor of an accelerometer as described above can be reduced.
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1. Field of the Invention
The present invention relates to processes for fabricating semiconductor devices; more particularly, processes for fabricating control gate lines for floating gate field effect transistors.
2. Description of the Related Art
The gate structure of a conventional floating gate field effect transistor (FET) includes a gate oxide layer provided on a substrate, a floating gate provided on the gate oxide layer, and a control gate separated from the floating gate by an inter-gate oxide layer. The control gate has conventionally been formed of a polysilicon layer or a polysilicon layer with a silicide layer overlying the polysilicon layer. The control gate is usually fabricated with a polysilicon layer adjacent to the inter-gate oxide in order to maintain the device characteristics provided by a polysilicon gate.
The desire to increase the speed and to reduce the power consumption of semiconductor devices has prompted the use of multi-layer structures, including a silicide layer overlying the polysilicon layer, to take advantage of the lower resistivity of the silicide. Several problems are associated with forming a silicide layer on a polysilicon layer. One such problem is that the doping level of the polysilicon must be low to insure that the silicide will adhere to the polysilicon. Poor adhesion results in silicide lift-off and device failure. Doping levels up to approximately 5.times.10.sup.19 cm.sup.-3 have been utilized; however, greater doping levels increase the probability of device failures beyond acceptable limits. Doping levels below 5.times.10.sup.19 cm.sup.-3 for the polysilicon layer create a large resistivity and power consumption and reduce speed. Further, since polysilicon is usually doped with an N-type dopant, in the fabrication of CMOS devices, the low doping level of the polysilicon layer allows P-type dopants (used to form the source and drain regions in P-channel devices) to neutralize, or invert, the doping (or conductivity type) of the polysilicon layer. An inversion of the conductivity of the polysilicon layer from N-type to P-type doping radically changes the threshold voltage (V.sub.t) of the device.
A further problem associated with the formation of a multi-layer control gate is that the device must be removed from the furnace tube, or vacuum chamber, after the deposition of the polysilicon layer to allow the polysilicon layer to be doped before the silicide layer is deposited. Each time the device is removed from the furnace tube one of two problems arise. The cooling of the furnace tube to insert the wafers causes the polysilicon accumulated on the tube walls to warp or break the furnace tube due to the divergent coefficients of thermal expansion of polysilicon and quartz. Alternatively, if the tube is maintained at a high temperature and the wafers are inserted into a hot tube there is a high risk of wafer oxidation, even if a flow of an inert gas is provided, which causes yield problems.
The problem of oxidation is more severe if buried contacts are formed. Buried contacts require the removal of the inter-gate oxide and the gate oxide in the region where the buried contact is to be formed. This leaves the substrate exposed and oxidation of the substrate in the buried contact region as the wafer is inserted into a hot furnace tube will ruin a die.
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{
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1. Field of the Invention
This invention relates to a catalyst deterioration-determining system for internal combustion engines, which determines deterioration of a catalyst arranged in the exhaust system of the engine, for purifying exhaust gases emitted from the engine.
2. Prior Art
To determine deterioration of a catalyst provided in an internal combustion engine, which purifies exhaust gases emitted from the engine, a catalyst deterioration-determining method is conventionally known, for example, from Japanese Laid-Open Patent Publication (Kokai) No. 5-106494, which controls the air-fuel ratio of an air-fuel mixture supplied to the engine in a feedback manner responsive to an output from an oxygen concentration sensor arranged in the exhaust passage of the engine at a location downstream of a catalyst arranged in the same, measures an inversion period of the output from the oxygen concentration sensor, and determines whether or not the catalyst is deteriorated, based on the measured inversion period.
According to the conventional method, however, the determination of deterioration of the catalyst is carried out by comparing the measured inversion period as it is with a predetermined reference value without contemplating operating conditions of the engine at the measurement. As a result, the measured inversion period contains an error depending on operating conditions of the engine at the measurement. Therefore, the conventional method remains to be improved in the determination accuracy.
Further, according to the conventional method, it is difficult to determine the deterioration degree of the catalyst with high accuracy, and therefore the method still remains to be improved in order to satisfy stricter legal regulations of exhaust gases.
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{
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Currently, research and development efforts have been actively made for various display devices, and of these, an organic electroluminescence (EL) device draws attention since it can emit high-intensity light at low voltage. Recently, there has been demand for improvement in device durability, and the electroluminescent device is also required to be improved in durability.
As suitable materials for improving durability of such devices, various aromatic condensed-ring hydrocarbon materials have been proposed. For example, JP-A-8-12600 (“JP-A” means unexamined published Japanese patent application) and JP-A-2001-335516 disclose diphenyl anthracene derivatives.
Since, however, the above aromatic condensed-ring materials generally have a low T1 energy level, they are disadvantageous in efficiency of energy transfer to a dopant. To improve the light emission efficiency, it is desired to develop aromatic hydrocarbon materials having higher T1 energy levels.
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{
"pile_set_name": "USPTO Backgrounds"
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Traditional hearing aid processors operate independently within a user's left and right ear (see e.g. U.S. Pat. Nos. 8,005,246; 8,406,442). As each hearing aid only receives a mono signal, there is no need to perform centralized or stereo processing on an incoming sound stream, which is simply processed locally by the hearing aid or mono receiver. However, the advent of wireless audio transmission technologies such as Bluetooth has enabled audio processing to become centralized on one core processor, allowing for more sophisticated stereo sound processing techniques. In these instances, a stereo signal is received at a single decoder and the decoder extracts a multichannel audio signal from the received stereo signal (see e.g. U.S. Pat. No. 9,755,704). The multichannel audio signal audio data is then processed using a stereo augmentation process and outputted to the appropriate speaker. Relative to a conventional hearing aid, here the augmentation happens as part of one process, not two independent processes.
As more features have been added to the suite of capabilities on smart devices and hearing wearables (“hearables”) employing Bluetooth or other similar short-range wireless interconnection methods, strains on processing power have become increasingly apparent. Sound augmentation is a computationally expensive process and there exists a need to devise efficient means to perform this process while maintaining the integrity of the hearing experience for the user. Accordingly, it would be desirable to provide computationally efficient and high-quality sound augmentation processing methods for stereo audio devices.
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{
"pile_set_name": "USPTO Backgrounds"
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1. Field of the invention
The present invention relates to a copying machine having a device for producing a light image of original documents which is both modular and removable. More specifically, the present invention relates to such a copying machine for photographic reproduction.
2. Brief description of the prior art
The known, prior art copying machines used in photographic reproduction are designed for copying only one type of original document, in particular the photographs. Such prior art copying machines are unable to copy other types of original documents.
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{
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This invention relates generally to semiconductor devices and more particularly to high electron mobility field effect transistors, also known as modulation doped field effect transistors.
A relatively new heterostructure exhibiting great operational speed has appeared in the field of transistor technology. The device is currently known by several different names, including: high electron mobility transistor (HEMT), high electron mobility field effect transistor (HEMFET), modulation doped field effect transistors (MODFET), and two dimensional electron gas field effect transistor (TEGFET). The device is generally characterized by the combination of doped aluminum gallium arsenide (AlGaAs) on undoped gallium arsenide (GaAs) separated by a heterojunction. This causes a quasi two-dimensional electron gas (2DEG) to be produced and confined to the small band-gap side of the heterointerface. Charge carriers, i.e. electrons, are introduced into the structure by the higher band-gap material aluminum gallium arsenide, whereupon they then diffuse to the lower band-gap material gallium arsenide where they are confined by the energy barrier at the heterojunction. Since the gallium arsenide layer is not doped, very high electron mobility and large electron velocities at very small values is permitted. Control of the charge, i.e. electron flow, between two electrodes called the source and drain is provided by an intermediate Schottky barrier electrode, called a gate electrode, which is placed on the doped gallium arsenide layer or is recessed and placed on the doped aluminum gallium arsenide layer. This device has been described in much greater detail in an article entitled, "The HEMT: A Superfast Transistor", by H. Morkoc, et al. in the IEEE Spectrum, February, 1984, at pp. 28-35. This publication, moreover, is meant to be incorporated herein by reference.
It is an object of the present invention, therefore, to provide a new and improved semiconductor device.
It is another object of the invention to provide an improvement in field effect transistors.
It is yet another object of the invention to provide an improvement in ultra high speed field effect transistors.
Still a further object of the invention is to provide an improvement in high electron mobility field effect transistors.
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{
"pile_set_name": "USPTO Backgrounds"
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