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Chang; David B.
Tustin, CA
No. of patents:

1 2

Patent Number Title Of Patent Date Issued
7378188 Storage device and method for sorption and desorption of molecular gas contained by storage site May 27, 2008
An apparatus and method for sorption and desorption of molecular gas contained by storage sites of graphite nano-filaments randomly disposed in three-dimensional reticulated aerogel.
7372031 System and method for sensitive photon detection May 13, 2008
A sensitive photon detection system generates an electronic photon sensor signal as a K factor times a number N photons per unit time. The system is configured by combining a separate optical amplifier with a gain factor K1 with a photo detector with a gain factor K2 such that K may be
7122008 Blood pressure diagnostic aid October 17, 2006
A medical diagnostic method using systolic and diastolic blood pressures, and pulse frequency of a patient is provided to compute a normalized diastolic distensibility value and a normalized peripheral resistance value, and to automatically compute the product of the normalized diast
7114384 Acoustic adiabatic liquid quantity sensor October 3, 2006
An adiabatic liquid volume sensor system is described, which employs a main chamber in a back-to-back configuration with a reference chamber of known volume. The system measures liquid volume in the main chamber by making low frequency acoustic measurements of the acoustic pressure d
6974415 Electromagnetic-acoustic imaging December 13, 2005
Ultrasound induced by RF irradiation within FDA exposure limits is produced with sufficient signal-to-noise ratio to allow acquisition of sub-millimeter resolution images within practical time frames.
6906003 Method for sorption and desorption of molecular gas contained by storage sites of nano-filament June 14, 2005
A system and method for sorption and desorption of molecular gas contained by storage sites of graphite nano-filaments randomly disposed in three-dimensional reticulated aerogel.
6849855 Method for marking and identifying objects coated with up-conversion material February 1, 2005
A method of marking and identifying an object (10) by the marking consists of applying to an object (10) an up-conversion material (12), then irradiating the object (10) with infrared electromagnetic radiation (16) and, finally, observing the irradiated object to detect the spectrum of
6535625 Magneto-acoustic imaging March 18, 2003
An apparatus having a coil of wire, energized by a repetitively pulsed radio frequency (RF) power source to provide electromagnetic fields to a region within a body. A scanning, directional hydrophone acoustically connected to the body, samples ultrasonic radiation generated by the RF
6495819 Dual-interferometer method for measuring bending of materials December 17, 2002
A method of two interferometric configurations to measure bending of an extended element. The measurement arm of each configuration is a long optical fiber. A first interferometric configuration has a segment of its measurement arm attached to one side of the element. The second inte
6463202 Optimization of curved waveguide design to reduce transmission losses October 8, 2002
A waveguide designed to minimize bend-induced losses. The waveguide has three regions of varying indices of refraction. The indices of refraction are chosen so that the field is a trigonometric function in the core region, evanescent in the intermediate region, and trigonometric again in
6166815 Constantly high sensitivity fiber optic interferometer sensor December 26, 2000
A fiber optic interferometric sensor (150) having constantly high sensitivity by use of two lasers (152, 154) that simultaneously output at first and second wavelengths. By judicious choice of the wavelengths, the optical path length difference between the two interferometer paths (164,
5531116 Apparatus and method for phase tomographic determination of fluid currents July 2, 1996
An array of acoustic signal sources and sensors are positioned in a fluid. Acoustic signals propagated through the medium are subjected to phase differences as they pass through fluid currents. An eikonal description of the acoustic waves propagating through the fluid medium is used to d
5469519 Optical waveguide image transmission system and method November 21, 1995
An improved image transmission system which includes an elongate optical waveguide 15 having an input aperture 17 and an output aperture 19. Optical apparatus 11, 13 is provided for injecting a transform of an image into the waveguide. In a specific implementation, the Fourier transform
5454047 Optical method and system for generating expansion coefficients for an image processing function September 26, 1995
A system for optically generating expansion coefficients for an image processing function. The invention (10) includes a first optical element (18) for providing a transform of an image provided at a first image plane (16). A second optical arrangement (20) provides a product of the
5405680 Selective emissivity coatings for interior temperature reduction of an enclosure April 11, 1995
Selective emissivity coatings are disclosed for temperature reduction of enclosures such as vehicles and building structures. The coating includes a selective emissivity material such as silicon-oxy-nitride having a desired thermal emissivity function which is high in the 8-13 micron
5361383 Optical fiber having internal partial mirrors and interferometer using same November 1, 1994
An optical fiber disposed to partially internally reflect optical energy passing therethrough is disclosed herein. The optical fiber 10 of the present invention includes an internal partial mirror disposed to partially transmit and to partially reflect optical energy incident thereon
5361034 Apparatus for measuring the conductivity of a fluid November 1, 1994
An apparatus for measuring the conductivity of a fluid is disclosed. The invention 10 provides both a contact and non-contact monitoring of fluid conductivity by measuring the A.C. dielectric properties of the fluid. The invention 10 transmits an electromagnetic wave into the fluid 22 an
5345522 Reduced noise fiber optic towed array and method of using same September 6, 1994
A sensitive towed optical fiber sensor array 50, wherein the fiber sensors (60A-60N) are connected in parallel, and the optical fiber cable (34) is paid out from the towing ship at a velocity about equal to but opposite to the velocity of the towing ship. The fiber sensors (60A-60N) are
5311137 Liquid crystal electric field tester for circuit boards May 10, 1994
A nondestructive noninvasive device and method for testing printed circuit boards (PCBs) through the utilization of a liquid crystal material which visually images the electric fields of the PCBs. Circuit faults resulting in a change of current flow in a PCB produce recognizable changes
5291032 Fiber optic evanescent wave fuel gauge and leak detector using eccentric core fibers March 1, 1994
An optical fiber evanescent wave fuel sensor, employing a light source with a wavelength selected to be at the strong infrared absorption lines of the fuel, typically hydrocarbons. The amount of light leaking from the optical fiber is an exponential function of the length of the fiber in
5289266 Noncontact, on-line determination of phosphate layer thickness and composition of a phosphate co February 22, 1994
A nondestructive method and apparatus is disclosed for determining the thickness and composition of a zinc phosphate layer applied to a metal surface, such as sheet metal on an automotive assembly line. The phosphate layer is irradiated with infrared light which is at least partially
5270538 System for accurately detecting changes in temperature and pressure December 14, 1993
A system adapted for attachment to a device that undergoes changes in temperature and pressure, and for detecting changes in temperature and pressure in the device comprises a mechanism for attaching the system to the device and an optic device that includes pressure-responsive, temp
5251482 Low frequency acoustic fuel sensor October 12, 1993
An acoustic fuel (or other liquid, powder or solid) sensor is disclosed. The sensor measures the volume of fuel in a container of known size. The air within the container is excited by an acoustic transducer. The transducer is driven by a frequency scanning source, and the frequency
5250326 Reduction of nonmetallic coating surface vertical irregularities by electrostatic pressure October 5, 1993
A time-efficient method for smoothing a surface 20 of an applied coating composition 22 is disclosed herein. In particular, the present invention sets forth a technique for expediting the subsidence of coating surface nonmetallic vertical irregularities R1, R2. The technique of the prese
5237281 Ion drag air flow meter August 17, 1993
An ion drag air flow meter (10) including a gas ionizer (16), an ion collector (14) and apparatus (30) for converting the collected ions into a signal providing an indication of the flow of a gas (40).
5235179 Evanescent wave liquid level sensor with density compensation August 10, 1993
An evanescent wave liquid level sensor for measuring the density-compensated level of a liquid in a container. The sensor employs an eccentric core optical fiber fully immersed in the liquid to be measured. Light is injected into one end of the fiber. Some of the light will be lost d
5233673 Output steerable optical phased array August 3, 1993
Optical phased arrays employing a large number of light emitters and optical phase delays between adjacent emitters to steer and focus an optical beam from the contributions of all the light emitters. The array can include a laser oscillator (22) as the light source, with the laser l
5228856 Optics approach to low side compliance simulation July 20, 1993
A low cost visual simulation system (100) for training simulators is disclosed. Aerial photo transparencies are used directly as image sources without creating a digital data base. The approximately correct image perspective is generated optically by a deformable mirror (114) and a zoom
5223763 Wind power generator and velocimeter June 29, 1993
An apparatus and method are disclosed for producing electrical power from wind flow. The apparatus includes a conduit (13) with a variably sloped wall (59) for channeling the wind flow along a predetermined path (23), a baffle (25) positioned in the path of the flow for forming vortices
5222161 Method and apparatus for compressing a light pulse June 22, 1993
This invention discloses a method and apparatus for shortening the length of a pulse of light. Generally, the method entails altering the index of refraction of an optical medium (14) through which the pulse of light is traveling at an area of the medium (14) where the front end of the p
5220180 Fiber optic fuel and liquid gauge having an open rigid "J" shaped tube June 15, 1993
A fiber optic fuel or liquid level gauge is disclosed which determines the liquid level by measuring the amount of light loss due to evanescent transfer to the fuel or liquid. An optical fiber is supported in the fuel or liquid tank, with a first end adjacent the highest possible liquid
5212583 Adaptive optics using the electrooptic effect May 18, 1993
An adaptive electroopical lens system for use in optical data storage systems, optical phased arrays, laser or other optical projectors, and raster scanning devices, and the like. The invention provides an electrooptical means for scanning an optical beam or moving an optical storage
5210779 Apparatus and method for focusing hard X-rays May 11, 1993
A dislocation-free, composite-substance crystal having a lattice constant which decreases over the length of the crystal (38) convergently focuses beams of hard X-rays or gamma rays (11). A single-substance, dislocation-free crystal (34) collimates diffuse beams of hard X-rays or gam
5208766 Automated evaluation of painted surface quality May 4, 1993
Human aesthetic evaluation of a finished painted surface, such as an automotive body, is automatically simulated by analyzing a distorted reflected test pattern from the finished surface. Fourier power spectra of the distorted test pattern are generated to form a parameterization of the
5179028 Antibody coated crystal chemical sensor January 12, 1993
A sensor for detecting the presence of a particular chemical by determining the absolute frequency shift in the oscillating frequency of an antibody-coated oscillator. Specific antibodies deposited on a high Q crystal oscillator detect the change in frequency as chemical particulates
5177970 Refrigerator of air conditioner based on a fluid of electric dipoles January 12, 1993
A refrigeration apparatus wherein the working fluid is a suspension of electric dipoles. The apparatus conducts the fluid from the region to be cooled to a heat exchanger, and employs different fluid conduit geometries. The fluid conduits present the fluid to the region to be cooled
5165242 Refrigerator or air conditioner based on a magnetic fluid November 24, 1992
A refrigeration apparatus employing a working fluid of magnetic dipoles. The apparatus exploits a phase change in the working fluid from unaligned magnetic dipoles to aligned magnetic dipoles, so that no compression of the fluid is required. In a first embodiment, alignment is achieved b
5165084 System and method for measuring changes in sea level November 17, 1992
A system for determining changes in sea level based on the measurement of distance between capacitive elements. The system includes an electrically conductive sphere 17, 117 mounted on an electrically non-conductive buoy 13, 113, positioned a predetermined distance above sea level with t
5164608 Plural wavelength fiber optic liquid level sensor for multiple liquids November 17, 1992
A fiber optic liquid level sensor for measuring the level of multiple immiscible liquids in a container (20). An end of an optical fiber (24) is immersed in the liquids in the container (20). Light is injected into the other end of the fiber. The ratio of transmitted to the reflected lig
5160634 Desalinization system November 3, 1992
A system and method are disclosed for desalinating sea water. The system includes an energy source such as a laser 13, and a container 19 (partly or wholly transparent) for holding the sea water, the sea water having sodium and chlorine ions and a solvent (H.sub.2 O) with a predetermined
5155792 Low index of refraction optical fiber with tubular core and/or cladding October 13, 1992
An optical fiber having an index of refraction less than that conventionally available. The low index of refraction fiber 10 of the present invention includes a fiber core 20 of a first index of refraction. The fiber core 20 circumscribes a longitudinal axis, and is surrounded by a c
5149957 Semiconductor-to-metal optical switch for power limitation in the infrared September 22, 1992
A semiconductor-to-metal optical switch or device for power limitation in the infrared spectral region includes two thin semiconductor layers sandwiched between two transparent electrodes. An electrical voltage is applied across the two semiconductor layers to produce an active device
5132831 Analog optical processing for the construction of fractal objects July 21, 1992
An analog optical processor for performing affine transformations and constructing fractal objects. An optical processor for optically performing an iterated affine transformation includes a rotating prism, an imaging lens and a translatable mirror, together with a pulsed laser as an
5118932 Shaft rotation rate sensor with a diffraction grating producing a velocity-related beat frequenc June 2, 1992
A shaft rotation rate sensor for turbine engines. A reflective radial grating on the surface of the turbine shaft is employed in conjunction with an electromagnetic wave source and beam combining elements to mix two beams of frequency f and f.+-..DELTA.f, where .DELTA.f is proportional t
5117676 Leak detector for natural gas pipelines June 2, 1992
A simple acoustic detection system is described for measuring leaks from long gas pipelines. Microphones are strung along (and attached to) the pipeline exterior. The outputs of the microphones are spectrally analyzed. A peak at a frequency f.congruent.V.sub.s /(2d) and its harmonics
5112121 Display system for multiviewer training simulators May 12, 1992
A display system is disclosed which employs multiple holographic elements for selectively reflecting images from separate projectors to one or more distinct viewing volumes. The display system provides the capability to project differing perspective images to individual crew members loca
5100230 True ground speed sensor March 31, 1992
A speed sensor for a moving vehicle. A transmissive grating is used in conjunction with an electromagnetic wave source and beam combining waveguide to mix two beams of frequency f and f+.DELTA.f, where .DELTA.f is proportional to the speed of the grating relative to the ground. The s
5094758 Desalinization system and method March 10, 1992
A system and method are disclosed for desalinating sea water. The system includes an energy source such as a laser 13, and a container 19 (partly or wholly transparent) for holding the sea water, the sea water having sodium and chlorine ions and a solvent (H.sub.2 O) with a predetermined
5086972 Enhanced electrostatic paint deposition method and apparatus February 11, 1992
An enhanced electrostatic paint deposition apparatus (10) comprising a nozzle (16), a conduit (14) coupled to the nozzle for supplying paint (12) thereto, and a plurality of electrically conductive whiskers (18) positioned within the nozzle for applying an electrostatic charge to dro
5077482 Liquid gauge having an optical fiber with flexible membrane enclosure December 31, 1991
A fiber optic fuel or liquid level gauge is disclosed which determines the liquid level by measuring the amount of light loss due to evanescent transfer to the fuel or liquid. An optical fiber is supported in the fuel or liquid tank, with a first end adjacent the highest possible liquid
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