Patents Assigned to Virginia Polytechnic Institute and State University
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Patent number: 5442079Abstract: There are described improved processes for the synthesis of a desired lactone useful as a synthon, the improved processes comprising oxidizing a protected arene diol with permanganate and periodate or subjecting a substituted epoxydiol to periodate oxidation to yield the desired lactone.Type: GrantFiled: May 10, 1993Date of Patent: August 15, 1995Assignee: Virginia Polytechnic Institute and State UniversityInventors: Tomas Hudlicky, Martin Mandel
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Patent number: 5442540Abstract: A full-bridge zero-voltage-switching pulse-width-modulated converter employs a saturable reactor in place of the linear inductor in order to reduce current stress on the active switches, reduce voltage stress on the rectifier diodes, and reduce secondary parasitic ringing. The zero-current-switching full-bridge pulse-width-modulated converter embodiment of the invention contemplates the provision of active switches that are zero-current-switched and passive switches, such as diode switches, that are zero-voltage-switched.Type: GrantFiled: June 25, 1992Date of Patent: August 15, 1995Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Guichao C. Hua, Fred C. Lee
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Patent number: 5431958Abstract: A method to produce high quality doped and undoped lead zirconate titanate (PZT) thin films by metalorganic chemical vapor deposition is disclosed. The PZT thin films with the perovskite structure were deposited on sapphire disks, Pt/Ti/SiO.sub.2 /Si wafers, and RuO.sub.x /SiO.sub.2 /Si wafers by both hot-wall and cold-wall CVD reactors at deposition temperature as low as 550.degree. C. and a reduced pressure 6 torr. The source materials include metalorganic precursors and oxidizing agent. The metalorganic precursors can be metal alkoxides, metal acetylacetonates, or metal .beta.-diketonates. Preferably, the precursors are lead tetramethylheptadione for Pb component, zirconium tetramethylheptadione for Zr component, and titanium ethoxide for Ti component and the oxidizing agent is oxygen. The stoichiometry of the films can be easily controlled by varying the individual precursor temperature and/or the flow rate of the carrier gas. The Pb(Zr.sub.0.82 Ti.sub.0.18)O.sub.Type: GrantFiled: December 31, 1992Date of Patent: July 11, 1995Assignees: Sharp Kabushiki Kaisha, Virginia Polytechnic Institute and State University, Ceram, Inc.Inventors: Seshu B. Desu, Chien-Hsiung Peng
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Patent number: 5422718Abstract: The elastic-port immersion cell (10) is an optical oil immersion vessel which has a flexible latex (or other) sheath (24) protruding from its sidewall. The sheath is affixed to an opening in the wall of the vessel using a collar, O-ring (26) or other connecting means. The base of the vessel is an optical glass window. A sample (20) mounted on to the end of spindle (14) is placed into the cell. The end of the spindle (14), without the sample, is inserted into the sheath and the latex together with the spindle is attached to a goniometer head of a spindle stage such that the spindle is horizontal. Immersion oil (22) that has a refractive index similar to the sample is added to the cell until the sample is totally submerged. Minute features within the sample (20) may then be observed under the microscope as the sample is rotated 360 degrees about a vertical or horizontal axis. The latex sheath prevents the oil from escaping from the cell and also provides the flexibility required to orient and rotate a sample.Type: GrantFiled: May 10, 1993Date of Patent: June 6, 1995Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventor: Alan J. Anderson
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Patent number: 5407479Abstract: .beta.-Al.sub.2 TiO.sub.5 protective coatings have been developed for both dense and porous ceramics such as SiC and Si.sub.3 N.sub.4 using a chemical solution processing method involving the hydrolysis and condensation of aluminum tri-sec butoxide and titanium butoxide. The solution viscosities, pH values, H.sub.2 O/alkoxide molar ratios, and dip coating withdrawal rates required for crack-free .beta.-Al.sub.2 TiO.sub.5 are 1.0 to 6.2 cP, pH 1-4.5, molar ratio 1.5-10, and withdrawal rate of 2.2-8.0 cm/min, respectively. Conversion of the amorphous coating to crystalline .beta.-Al.sub.2 TiO.sub.5 is achieved by a succession of calcination below 450.degree. C. and a final heat-treatment at 1300.degree. C. for ten hours with controlled heating and cooling rates.Type: GrantFiled: July 28, 1993Date of Patent: April 18, 1995Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State UniversityInventors: Tawei Sun, Nancy R. Brown, Jesse J. Brown, Jr.
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Patent number: 5396260Abstract: Mineral content in processed ore and coal content in coal slurries are determined using a video system. A video image is taken of a sample, the video image is digitized, and gray levels are assigned to points or areas on the video image. The distribution of the gray levels for the image provides an indication of the purity of the minerals in the ore sample. The mean gray level for the image provides an indication of the mineral content of interest in the sample. The video system should be calibrated using ores that normally occur in the process environment and using samples of controlled moisture content. The video system has particular utility in determining phosphate content and calcium ratio in phosphate ores.Type: GrantFiled: December 22, 1992Date of Patent: March 7, 1995Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Gregory T. Adel, Roe-Hoan Yoon, Gerald H. Luttrell
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Patent number: 5387629Abstract: Polymers containing the phosphine oxide moiety are identified as being particularly useful in applications where resistance to atomic oxygen etching is required and in applications where second order nonlinear optical effects will be utilized. Particularly preferred polymers for these two applications include poly(arylene ether phosphine oxide)s (PEPOS), and novel PEPOS which include phenolphthalein sub-units and derivatives thereof have been prepared.Type: GrantFiled: July 30, 1993Date of Patent: February 7, 1995Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: James E. McGrath, Carrington D. Smith, Duane B. Priddy, Jr., Timothy Pickering
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Patent number: 5382320Abstract: A method of reactive ion etching both a lead zirconate titanate ferroelectric dielectric and a RuO.sub.2 electrode, and a semiconductor device produced in accordance with such process. The dielectric and electrode are etched in an etching gas of O.sub.2 mixed with either CHCl.sub.2 CF.sub.3 or CHClFCF.sub.3.Type: GrantFiled: July 22, 1993Date of Patent: January 17, 1995Assignees: CERAM Incorporated, Sharp Kabushiki Kaisha, Virginia Polytechnic Institute and State UniversityInventors: Seshu B. Desu, Wei Pan
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Patent number: 5373660Abstract: A trellis system which can be used with raspberry and other fruit production includes a plurality of structural units (36) which are essentially two dimensional in shape to allow for flat packing and shipping. Trellis wires (34) are strung over a plurality of structural units (36) positioned in a trellis row and are subsequently anchored (34) to the ground at each end of the trellis row. The structural units (36) are positioned directly on the ground surface at any location desired by the user and do not need to be staked in the ground. In one embodiment, the structural units are a rigid one piece construction (10, 12, 14, or 16). In another embodiment, the structural units are made on site by connecting to essentially identical linear pieces (52 or 60) together. A wire loop connector (42 or 44) allows for quick and effective connection of a wire (46) once the structural units are positioned.Type: GrantFiled: June 8, 1993Date of Patent: December 20, 1994Assignees: Virginia Tech Intellectual Properties, Inc., Virginia Polytechnic Institute & State UniversityInventor: Herbert D. Stiles
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Patent number: 5362838Abstract: There are disclosed carbonate polymers having ethenyl aryl moieties. Such carbonate polymers are prepared from one or more multi-hydric compounds and have an average degree of polymerization of at least about 1 based on multi-hydric compound. These polymers, including blends thereof, can be easily processed and shaped into various forms and structures according to the known techniques. During or subsequent to the processing, the polymers can be crosslinked, by exposure to heat or radiation, for example, to provide crosslinked polymer compositions. These compositions have a good combination of properties, including for example, processability into shaped articles having unexpectedly good combinations of toughness, solvent resistance, ignition resistance, modulus and resistance to thermal linear expansion.Type: GrantFiled: February 19, 1993Date of Patent: November 8, 1994Assignees: Virginia Polytechnic Institute and State University, The Dow Chemical CompanyInventors: James E. McGrath, Stephen E. Bales, Daniel M. Knauss, Thomas A. Chamberlin, Michael J. Mullins, Maurice J. Marks
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Patent number: 5357040Abstract: Fine particles of semi-crystalline ketone-containing aromatic polymers (PEEK, PEKK, etc.) are produced by controlling the rate and conditions of hydrolysis of an amorphous polyarylketimine intermediate. The choice of acid and its concentrations affects the rate of ketimine hydrolysis and subsequent particle formation. In addition, zero or reduced amounts of agitation during hydrolysis has been found to promote the formation of smaller (submicron) sized particles which are spherical in shape, while greater amounts of agitation or shear stress applied during hydrolysis results in nonspherical, larger particles. Carbon fiber reinforced composites were made from aqueous suspensions of these particles that were dispersed or stabilized by a water soluble polymer.Type: GrantFiled: February 24, 1993Date of Patent: October 18, 1994Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: James E. McGrath, Keith R. Lyon, Richey M. Davis, Ann Texier, Atilla Gungor
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Patent number: 5355417Abstract: An active noise control system using a compact sound source is effective to reduce aircraft engine duct noise. The fan noise from a turbofan engine is controlled using an adaptive filtered-x LMS algorithm. Single multi channel control systems are used to control the fan blade passage frequency (BPF) tone and the BPF tone and the first harmonic of the BPF tone for a plane wave excitation. A multi channel control system is used to control any spinning mode. The multi channel control system to control both fan tones and a high pressure compressor BPF tone simultaneously. In order to make active control of turbofan inlet noise a viable technology, a compact sound source is employed to generate the control field. This control field sound source consists of an array of identical thin, cylindrically curved panels with an inner radius of curvature corresponding to that of the engine inlet.Type: GrantFiled: October 21, 1992Date of Patent: October 11, 1994Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Ricardo Burdisso, Chris R. Fuller, Walter F. O'Brien, Russell H. Thomas, Mary E. Dungan
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Patent number: 5339374Abstract: The fibers are bound together about 1 cm apart. An oxy-propane torch is used to heat the fibers so that they fuse together. At the same time, the two relatively movable translational stages to which the fibers are clamped are pulled apart to form a biconical tapered region in the fibers. The fibers are tapered until a desired coupling ratio is achieved. After the insertion loss is measured, the torch is reintroduced into the taper region and one side (e.g., the right side) of the taper region is rotated with a minimal increase in the taper length, i.e., the distance between the two stations is increased only enough to keep an even tension in the taper region.Type: GrantFiled: May 26, 1993Date of Patent: August 16, 1994Assignees: The Center for Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Kent A. Murphy, Michael F. Gunther, Richard O. Claus
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Patent number: 5314644Abstract: Means are provided for supplying a liquid surfactant solution, for supplying a gas under pressure, for mixing the liquid surfactant solution and the pressurized gas to form a liquid coarse dispersion of relatively large gas bubbles, and for receiving the liquid coarse dispersion to generate a liquid fine dispersion of relatively small micron-size gas bubbles.Type: GrantFiled: October 19, 1992Date of Patent: May 24, 1994Assignee: Virginia Polytechnic Institute and State UniversityInventors: Donald L. Michelsen, Felix Sebba
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Patent number: 5268199Abstract: Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.Type: GrantFiled: April 2, 1993Date of Patent: December 7, 1993Assignees: The Center of Innovative Technology, Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Jesse J. Brown, Jr., Deidre A. Hirschfeld, Tingkai Li
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Patent number: 5237488Abstract: An electrically conductive hinge provides for the transmission of electrical power and signals between a pivotally connected display unit and system unit of a portable computer and eliminates cable connections between the display unit and the system unit. Either the system unit, the display unit, or both units have a set of wipers which contact the conductive lines in the electrical track. The conductive lines are long enough to allow the display unit to be pivoted to and from its open and shut positions while the wipers remain in contact therewith. In one arrangement, the electrical track is manufactured on the hinge pin. In another arrangement, the electrical track is manufactured on a disk positioned at or near one end of the hinge pin.Type: GrantFiled: May 11, 1992Date of Patent: August 17, 1993Assignees: Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc.Inventors: Gregory T. Moser, Jane M. Shewchuck
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Patent number: 5233628Abstract: A communications stimulation system allows a user to perform a quantitative or subjective test of digital baseband devices over wireless channels using actual measured or modeled propagation data. The digital wireless communication simulation system is capable of simulating the transient nature of channels and radio hardware so that loss of synchronization can be included in the simulation. The simulator is a combination of computer software and hardware that computes a convolution, in the time domain, of a sequence of binary digits or data symbols (i.e., the data stream) with a computer model of a radio transmitter, a propagation channel or channels and a receiver. The transmitter typically comprises a coder, a pulse shaper, a modulator, and a spreader. The propagation channel or channels may include impulsive and average noise levels, co-channel interference and adjacent interference levels, fading and multipath propagation events, and non-linear channel and radio system effects.Type: GrantFiled: May 29, 1991Date of Patent: August 3, 1993Assignee: Virginia Polytechnic Institute and State UniversityInventors: Theodore S. Rappaport, Victor Fung, Michael D. Keitz
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Patent number: 5225488Abstract: A method for blending polymeric materials includes the steps of producing a melt stream of a first polymer from a first extruder (12) and a separate melt stream of a second polymer from a second extruder (14), joining the melt streams at a T-junction (16), distributing the first polymer within said second polymer using a static mixer (10), and extruding the blend through a die (18). In particular, using this method liquid crystal polymer fiber reinforcement can be formed in-situ within a matrix material.Type: GrantFiled: May 1, 1991Date of Patent: July 6, 1993Assignees: Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc., Center for Innovative TechnologyInventors: Donald G. Baird, Ashish Sukhadia
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Patent number: 5224182Abstract: Tapered two-mode optic fibers are used as sensors with sensitivity varying as a function of length. The optical fiber sensors act as vibrational-mode filters thereby performing initial signal processing of the sensor signal. The sensors are based on the differential propagation constant in a two-mode fiber that is directly dependent on the normalized frequency or V-number. Tapering the fiber changes the V-number and hence can change the sensitivity of the sensor along its length. By choosing an appropriate weighting function in the manufacture of the sensor, it is possible to implement vibrational-mode analysis, vibrational-mode filtering and other functions that are critical in control system applications.Type: GrantFiled: August 29, 1991Date of Patent: June 29, 1993Assignees: Virginia Polytechnic Institute and State University, Virginia Tech Intellectual Properties, Inc., Center for Innovative TechnologyInventors: Kent A. Murphy, Ashish M. Vengsarkar, Michael F. Gunther, Brian R. Fogg, Richard O. Claus
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Patent number: 5189299Abstract: The present invention pertains to a strain sensor. The strain sensor is comprised of an optical wave guide, a device for providing optical pulses to the optical wave guide and a device for sensing localized strain in the optical waveguide. The sensing device determines shifts in arrival times of the optical pulses at the sensing device that correspond to the localized strain. The apparatus includes a light source, a light detector, and a waveguide connecting the source with the detector. The apparatus also includes means for generating light pulses from the source through the waveguide and means for repeatedly propagating at least one of the light pulses in a closed loop. The light source detects arrival times of the light pulses.Type: GrantFiled: May 22, 1990Date of Patent: February 23, 1993Assignees: Virginia Polytechnic Institute & State University, Virginia Tech Intellectual Properties, Inc., Center for Innovative TechnologyInventors: Bernd D. Zimmermann, Richard O. Claus, Kent A. Murphy, David A. Kapp