Abstract: The vibration and electrical characterization of a piezoelectric tactor actuator is described. The actuator is a rectangular laminated flat plate with two opposite sides simply supported and two others free. Under an axial compression from the supports, the plate deforms into a stressed shallow shell. Electrical high frequency harmonic signals within relatively low-frequency bursts are applied to the piezoelectric layers. Depending on the axial compression and pre-deflection, frequency and magnitude of electrical input, the tunable actuator exhibits frequency/mode-controlled high-force over large area vibrations with intense displacement jumps. A single-degree-of-freedom model and simplified 1-D models are provided. The tactor provides efficient conversion of electrical energy into mechanical.

Abstract: Modulated-structure polycrystalline or heteroepitaxial multilayers of PZT/PT ferroelectric thin films are deposited on a substrate, preferably by laser ablation. The laser ablation of the PZT/PT layers onto a prepared substrate occurs while maintaining the substrate at a temperature between 380.degree. C. to about 650.degree. C. The target source for the PZT/PT laser ablated film may be either bulk PZT and PT ceramics or powders or individual metal oxides or metal pellets. The ferroelectric thin film device may be used for a random access memory.

Abstract: A laser-based multi-axis position measurement unit measures position deviations in 5 axes while traversing a 6th linear axis. The apparatus includes three components: 1) a laser-beam unit which emits two parallel laser beams; 2) a sensor unit including at least three laser-position sensors, one of them being transparent; and 3) a microprocessor or computer unit which converts X,Y laser position data from the three sensors to displacements in 5 axes: X (horizontal), Y (vertical), Pitch (angular motion about the X axis), Yaw (angular motion about the Y axis), and Roll (angular motion about the line of travel). Readout of the 6th axis, the line of travel, is provided by means of a separate linear transducer or laser-based ranging system. The device includes an arrangement of three digital sensors on two parallel laser beams to deduce position in 5 axes.

Abstract: A precision positioning system is used for resurfacing and repairing rails and guideways of large, heavy machinery at users facilities. The system has new components, an entire machining system, a new alignment system, parallel platforms for tool support and surface scanning. A sectioned, portable monorail frame is held by fixed supports at the locus of a heavy machine requiring guideway straightening. Fixed guides extend along the outer surface of the monorail. Guide wheels and drive wheels contact the guides and support and move an outer tubular beam carriage. An assembly of machining tools is adjustably positioned on the carriage. Laser alignment sources and sensors are connected to the carriage and to heavy machines off-axis and parallel to the monorail. Intelligent controls precisely position the tools for resurfacing the rails and guideways. Scanning and a printout of machine guideway accuracy, before and after the operation, provide written verification of quality improvement.

Abstract: A-compact, diode laser-based sensor has applications in biological and chemical analysis. Unlike existing optical waveguide-based sensors, no external coupling to external optical fibers or waveguides is required to perform optical chemical, immunological or nucleic acid-based assay or to detect the presence of toxic or otherwise important chemicals. The sensor includes a surface-sensitive diode laser having a substrate layer, an n-contact layer positioned on a bottom surface of the substrate, an n-clad layer overlying the top surface of the substrate, a first guide layer overlying the n-clad layer, a quantum well layer overlying the first guide layer, a second guide layer overlying the first quantum well layer, a p-clad layer overlying the second guided layer and a p-doped cap layer overlying the p-clad layer. A pair of electrodes separated by a surface-sensitive region is positioned on the cap layer.

Abstract: An apparatus and its accompanying method measures fluorescence decay, fluorescence amplitude and fluorescence polarization. The instrument includes a light emitting diode or laser diode light source, an amplified photodiode detector, and electronics and software for calculating the phase of the fluorescence from the computed inner product of the scattering and fluorescence signals. The electronics for measuring fluorescence decay includes two signal synthesizers, two downconverters, a simultaneously sampling analog-to-digital converter and means for calculating the inner product of the downconverted waveforms. A signal source, preferably a direct digital synthesizer, is used in combination with a digital-to-analog converter to provide a controllable output signal. That signal drives a modulatable light source, which is a light emitting diode, a laser diode or a combination of the two. Excitation light from the light source excites the sample fluorophore which is immobilized in a solid material.

Abstract: Fluorescence measuring methods and apparatus use planar optical waveguides to excite fluorescence in the evanescent field of the waveguides and photodetectors to sense the fluorescence produced. Chemically sensitive fluorophores are bound to the evanescent regions of the planar optical waveguides. Substrates support the waveguides. Photodetectors, positioned in the substrates with fields of view normal to the waveguides, detect the fluorescence. Wavelength-selective material coating surfaces of the photodetectors allow fluorescence to be detected while restricting entry of light at the excitation wavelengths. The photodetectors have high aspect ratios for detection of fluorescence generated by the optical waveguides. Preferably, the photodetectors are closely coupled to the fluorescence generated in the evanescent field of the waveguide.

Abstract: A refreshable braille cell display uses a single moving part per tactile element. Tactile elements, formed from stainless steel tubing, are assembled in densely arranged modules. Lower ends of the tactile elements extend beneath the modules and are in contact with a pressurized medium. Shape memory alloy actuators are positioned in the tactile elements, isolated from any motion or flow in the pressurized medium. When a pressurized medium is delivered through a port in a tactile element, the actuator extends upward, thereby forcing the upper portion of the tactile element through a hole in the user contact surface. In that state the tactile element indicates information. When the tactile element is activated, current flows from an electrical contact at the lower end of the tactile element, through the actuator, and into the outer tube of the tactile element. The actuator heats, due to electrical resistance, contracts and exerts a downward force on the pressure medium.

Abstract: A method for developing large area highly oriented polycrystalline ferroelectric thin films using spin-on sol-gel deposition and laser crystallization techniques that allow for precise control of temperature distribution. The present invention improves quality, reliability, performance and cost effective production of ferroelectric non-volatile random access memory (FNVRAM) on thermally sensitive silicon and gallium arsenide semiconductor substrates compatible with very large scale integrated circuit technologies. The method is time effective, as crystallization is performed in three seconds as compared to thirteen hours in a conventional furnace for 1 cm.times.1 cm wafer. In addition, crystallization of the film is further achieved without exposing the underneath device structure to detrimental high temperature annealing conditions.

Abstract: An improved NiZnCo ferrimagnetic core material which may further contain elements from the group Cr, Mn or Li. The invention permits enhancement of magnetic properties and results in core materials capable of efficient operation at high frequencies on the order of 1-100 MHz over a wide range of magnetic flux densities, on the order of 1-2500 Gauss. The composition of base NiZnCo ferrites are adjusted through ionic substitution. The magnetic properties of the ferrite are further enhanced through Bi.sub.2 O.sub.3 and SiO.sub.2 additions and controlled sintering. Methods of manufacturing the core material are also disclosed.

Abstract: A highly sensitive surface plasmon waveguide sensor monitors the refractive index and thickness of thin adsorbed films. The sensor includes an optical waveguide formed by ion-exchange in a glass substrate, by selective densification of substrate material or by the incorporation of high refractive index materials during deposition of a dielectric layer. Two dielectric thin films are deposited on top of the waveguide. The layer closest to the waveguide has a lower refractive index than the guiding layer to form a buffer layer. The second dielectric layer, or tuning layer, has a higher refractive index. The tuning and buffer layers allow optimization of the resonance wavelength, full-width half maximum of the resonance wavelength range and amplitude of the resonance. The tuning layer is coated with a thin metallic layer, to effect surface plasmon resonance, such as gold, silver, aluminum or one or more semiconducting materials.

Abstract: A chemical sensor uses a semiconductor diode laser having a surface active region. A laser structure, including an active layer, a cladding layer, a barrier layer and a grating layer, is constructed on a substrate. A contact layer is deposited on a surface of the laser structure. One or more electrodes are positioned on the contact layer. A segmented electrode has a first contact pad, a second contact pad, and a surface active region between the first and second pads. A surface active region is created between the two electrodes. The tail of the lasing signal interacts with surface features of the diode laser or with chemical materials or probes in contact with the surface of the diode laser or in contact with coatings on the surface of the diode laser. Chemical changes in the ambient environment induce changes in the laser signal. The modified laser signal output is detected by a detector region integral with or separated from the laser structure.

Abstract: The present invention is a new electronic memory-assist device which can be used to remind an individual when it is time to take a prescribed medicine. The invention uses complementary metal-oxide semiconductor technology in conjunction with surface-mounted device technology to provide a programmable portable unit. The device has three parts: a body-carried reminder, a local interactive compliance processor and a supervisory unit. The reminder has a portable power supply, microprocessors, software, memory, an alarm, an input key and communication linkage to the compliance processor. The compliance processor has a central processing unit, a pill case, a modem and, possibly, a recharger for the portable power supply. The supervisory unit is connected to the central processing unit remotely by modems. The device operates by providing data to the user through an alarm that it is time to take prescribed medication. The alarm is visual, auditory, tactile or any combination of the three.

Abstract: A fluorescent sensor for chemical analysis has a light source, an optical waveguide, and a detector. Fluorophores are associated with the optical waveguide. When an impervious waveguide is used, a fluorophore-containing layer is applied to a surface of the waveguide. The fluorophores are excited by a laser, a light emitting diode, an electroluminescent source or a lamp source emitting light propagating at angles to the waveguide. The light source is modulated. A mirror can be used to direct the light beam. The angle of light incidence on the waveguide can be altered by moving the waveguide itself. The waveguide traps the laser-induced fluorescence and projects fluorescence signals through a suitable filter to a photodetector or otherwise wavelength-specific photodetector positioned near the waveguide structure. Remote operation of the sensor is achieved using optical fibers. Patterned waveguides allow multiple excitation sources to illuminate multiple fluorescent probe materials.

Abstract: A laser ablation deposition system includes a movable platform for supporting ferroelectric target material and a support structure for supporting a thermally sensitive semiconductor substrate within a chamber mounted on a moveable cabinet, and a laser for ablating the material mounted on a support frame along with various control components. The cabinet with the chamber may be moved away from the laser and support frame to allow the chamber to be raised to provide access to the components within the chamber. The system may be used to fabricate a multilayer thin film device using multicomponent oxides.

Abstract: An instrument is applied to the measurement of chemical species and concentration through the use of a chemically-sensitive coating on the eddy current coil or in the vicinity of the eddy current coil which produces a change in impedance of the probe through induced eddy currents in the coating. An eddy current or resonance circuit chemical detector is a non-contact sensor for measuring chemical species identity and concentration. The chemical detector is resilient and does not require reference electrodes. The chemical sensor is selective as a result of data available on the change in vector impedance of the probe, the change in resonant frequency of the tuned circuit, and the availability of data to construct a vector response from multiple probes having differing chemistries. The probe is used in extreme temperatures.

Abstract: Alumino-silicate glass-ceramic coated carbon-carbon composite and graphitic substrates having resistance to oxidation and thermal cycling. The coatings are fabricated from plasma-sprayed powders of beta-spodumene, cordierite, beta-eucryptite or beta-quartz and are rapidly recrystallized by laser processing.

Abstract: Wood composite materials containing veneer layers interposed with a thermoplastic adhesive containing a polyester such as polyethylene terephthalate and other thermoplastic polymer show increased impact resistance. The composite material may be manufactured using an adhesive transfer method or film extrusion.

Abstract: The laser brazing of the present invention offers the unique advantage of producing a high temperature hermetic bond while limiting the heat affected zone to the region of the joint. Laser brazing joins infrared (IR) and radio frequency (RF) ceramic materials to metals for radome applications. Using AG--Cu--Ti brazing alloys, zinc sulfide (ZnS) infrared windows were laser brazed to cylindrical titanium housings with no thermal degradation observed in crystalline properties of ZnS. Innovative glass-ceramic materials were also used as braze filler to produce over 30 ceramic-to-metal couples, including titanium Zns, Pyroceram/Kovar and niobium/sapphire. Benefits are in the production of strong, high temperature, hermetically sealed joints in aircraft and high velocity missile systems. An optimized laser brazing system is provided.

Abstract: An improved method and apparatus for optically sensing and measuring physical quantities such as magnetic fields, electrical fields, mechanical strain, temperature, sound and pressure. The apparatus aspects of the invention involve a sensor structure consisting of a sandwich of magnetostrictive, piezoelectric or other materials sensitive to the physical quantity measured which are spaced apart by two opposed parallel reflecting surfaces located on opposing sides of the sensitive material. The reflecting surfaces can include an array of plane mirrors, diffraction gratings, curved mirrors, or retro-reflecting spheres. In its method aspects, multiple optical reflections between the two surfaces provide a magnified optical phase shift when the shape of the slab that is sensitive to changes in the applied field causes mechanical strains in the material. The changed optical signal can be measured by a suitable measurement device such as an interferometer for phase comparison with a diffraction reference pattern.