Abstract: A polymeric or plastic coating is provided which protects coated structures by forming an intumescent insulative fire resistant barrier. The coating is formed from the product of mixing an aromatic polyisocyanate, an aromatic polycarboxylic compound and about 1 to about 20% by weight of furfuryl alcohol. The structure to be protected is coated with the product of the mixture and the coating is dried. An intumescent polyimide fire resistant foam is formed when the coating is exposed to a (non-flame) heat source at temperature ranging from about 110.degree. C. to about 140.degree. C.

Abstract: A method of stabilizing electrically conductive polymers to hostile environments is disclosed. The method comprises encapsulating the conductive polymer, e.g., polypyrrole or polyaniline, as a powder, a free-standing film or preferably in the form of a composite of a substrate, such as fiberglass fabric, impregnated with the conductive polymer, with a suitable resin, preferably an epoxy resin, as an encapsulating agent. The preferred method involves pre-pregging the fabric of the conductive composite with an epoxy resin and curing the resulting system.

Abstract: A dual deposition liftoff process is provided for obtaining clearly defined, planar integrated circuit pattern definition. After developing a photoresist pattern on a substrate, a thin layer of sealing material which is compatible with the integrated circuit is deposited over the photoresist and the uncovered portions of the substrate. The sidewalls of the photoresist are then etched, thereby undercutting the sealing material and forming a lip which overhangs the sidewalls. A second layer of material is deposited on top of the thin layer to provide the required thickness for the integrated circuit. The overhanging lip protects the sidewalls from deposition and thus a good liftoff of the photoresist with its overlying layers is obtained.

Abstract: An optical fiber rotation sensor includes an optical fiber coil and a laser for providing a source of coherent light. A beam splitter divides the light source into a first beam and a second beam. The first beam is coupled into a first end of the coil, so that the first beam propagates through the coil from the first end to a second end of the coil. A reflector, such as a mirror or a phase conjugate reflector, reflects the second beam back toward the beam splitter. A scalar phase conjugate reflector reflects the first beam at the second end of the coil so that the reflected first beam propagates back through the coil to the first end and is recombined with the reflected second beam in the beam splitter. A detector measures the phase difference between the reflected first beam component and the reflected second beam component in the recombined beam.

Abstract: A controllable, piecewise linear gain circuit includes a first field effect transistor (FET), the drain of which is connected to a first source of bias voltage and the gate of which is connected to the input to the circuit. A first capacitor is connected between the gate of the FET and a common ground. The drain of a second FET is connected to the gate of the first FET, while the gate of the second FET is connected to a second source of bias voltage. A second capacitor is connected between the source of the second FET and the common ground. With this configuration, the output voltage of the circuit may be measured across an output resistance connected between the common ground and the source of the first FET, such that the second FET will turn on and connect the second capacitor to the output of the circuit when a predetermined amount of charge has accumulated on the first capacitor, thereby reducing the gain of the circuit.

Abstract: Thin electrodes are coupled to a resistive film on an active semiconductive layer to form a gapless gate CCD (GGCCD). The active layer is formed ona semi-insulating substrate, and the resistive film is joined to the active layer by a Schottky barrier. The thin electrode coupled to the resistive film induce fringing fields near the surface to provide high speed charge transport and permit the use of a thin active layer.

Abstract: A monolithic accelerometer is fabricated with an integral cantilever beam sensing element which is etched out of a silicon wafer from the back surface. A thermal silicon oxide is formed on both surfaces of a (100) silicon wafer. Silicon oxide is removed from the back surface in a pattern which defines the sides of the cantilever beam and the sides of an alignment groove. The width and orientation of the openings in the silicon oxide are selected to control the depth of etching when the wafer is subsequently etched with an anisotropic etchant. An integrated circuit is then formed on the front surface and dry etching is used to complete the groove and separate the sides of the beam from the wafer.

Abstract: A method is disclosed which is capable of producing improved field effect transistors such as high electron mobility transistors and metal semiconductor field effect transistors. The method comprises a dual level photoresist deposition technique on a semiconductor wafer, in conjunction with a double lift-off and dummy gate procedure. In the process, T-bar shaped portions of overlying top and bottom photoresist layers are produced, one of such T-bar shaped portions forming a dummy gate. Metal is then deposited on the upper surface of the T-bar shaped portions and on the exposed surface of the substrate to form a source and a drain. In a first lift-off step the metal on the T-bar shaped portions and the underlying remaining top layer portions, are removed. An inorganic film such as SiO is then deposited on the remaining bottom layer portions and over the metal on the surface of the substrate.

Abstract: An electroluminescent (EL) material is sandwiched between parallel strips of electrodes running at right angles to each other. Pixels are formed where the electrodes cross to provide a thin film, EL display. The display includes a layer of insulating material which has a hole at each pixel. The backside electrodes extend into the holes, thus providing a high electric field only at the pixel locations. These backside electrodes are broad to assure electrical continuity despite any open-circuit created by burned-out pixels. The insulating material overlaps the edges of the frontside electrodes, thus reducing the electric field which concentrates at the electrode edge. The insulating layer and the backside electrode can be made black, or a light-absorbing, semi-insulating layer used in order to reduce light scattering and reflection. Transparent electrodes can be used to allow light to emit from either the front, the back, or both sides of the display.

Abstract: A conducting polymer is produced using cathodic deposition in an electrolyte. The etectrolyte comprises a solvent such as acetonitrile, carbon disulfide, a supporting electrolyte cation, and a transition metal ion. At a voltage of about -0.70 or higher, the carbon disulfide is reduced in the presence of the transition metal ion and a conducting polymer is deposited on the cathode.

Abstract: An antireflective optical film is placed between an incident media and a substrate to effect minimal reflectivity from the incident media-substrate interface over a broad spectral band. The film is designed by selecting a first material with a low refractive index and a second material with a high refractive index. A theoretical film is defined with a plurality of thin layers of equal thickness. The low refractive index or the high refractive index material is specified for each layer in the film. The reflectivity of the theoretical film is evaluated. The refractive index of one of the layers is changed to the alternate index and the reflectivity of the defined film is reevaluated. If the reflectivity of the film is improved, the alternate refractive index is assigned to the changed layer. The steps of changing, reevaluating, and assigning are repeated for each of the layers in the film until no further improvement in the reflectivity of the film is obtained.

Abstract: A device for measuring the water content in small samples of an ink-water mixture. The sample is used as the dielectric for a capacitor cell which includes inner and outer concentric electrodes. The ink sample fills a gap between the electrodes, thereby controlling the total capacitance of the cell. The cell is connected as part of an oscillator circuit, the output frequency of which varies in a known manner with the dielectric constant of the ink mixture, which in turn is determined by the mixture's water content. A display is provided which varies with the frequency of the output signal, thereby indicating the sample's water content. A mechanism is provided for conveniently removing the inner electrode so that a sample can be introduced, and then returning the inner electrode so that the sample floods the gap between the two electrodes.

Abstract: Laser energy is combined using dynamic beam splitters that can automatically accommodate changes in the laser cavity mode structure. Nonlinear optical methods and real time holography are employed to achieve phase locking among multiple lasers. A single laser output beam can be produced from a multitude of laser cavities which collectively contribute to the output power. No outside monitoring and servo mechanisms are required, since nonlinear optical processes automatically perform the functions of both monitoring and control. A coupled laser system includes two or more lasers, each laser having a resonant cavity, a laser gain medium in the resonant cavity, and a nonlinear optical element. Each nonlinear optical element is positioned in its respective resonant cavity to diffract laser energy from the cavity to a coupling beam by means of four-wave mixing (phase conjugation).

Abstract: A relative position sensor is suitable for inertial navigation situations in which deviations from a predetermined position schedule are detected. A standing wave is established between a pair of opposed phase conjugate reflectors in a resonating cavity, and relative movement between the standing wave and the cavity is sensed. Since the standing wave continues to travel at its initial velocity regardless of deviations from that velocity by the resonator, deviations in the position of the resonator relative to its projected position based on the initial velocity can be measured. In a preferred embodiment, four-wave mixers are used as the phase conjugate reflectors, the phase conjugate medium within the mixers is made coextensive with the wave propagation medium between the mixers, and relative movement is sensed by monitoring the intensity of the standing wave at at least one location which is fixed relative to the resonator.

Abstract: Improved Si.sub.3 N.sub.4 /ZrO.sub.2 composite ceramics are described, having low thermal conductivity and which are substantially free of surface spalling and material degradation. Such composites are produced by incorporating an additive, e.g. MgO, CaO or Y.sub.2 O.sub.3, preferably Y.sub.2 O.sub.3, in suitable molar proporations based on ZrO.sub.2, and sintering the mixture with Si.sub.3 N.sub.4. In a preferred embodiment a powder mixture of 70% Si.sub.3 N.sub.4 and 30% ZrO.sub.2, by volume, and containing 6.6 mole percent Y.sub.2 O.sub.3 based on ZrO.sub.2, is formed and is sintered to produce a composite ceramic. The Y.sub.2 O.sub.3 is preferably pre-reacted with the ZrO.sub.2 to form a solid solution. A sintering aid, preferably Al.sub.2 O.sub.3, e.g. in an amount of about 2 to about 4%, by weight of the total mixture, can be added to permit production of the Si.sub.3 N.sub.4 /ZrO.sub.2 composite by pressureless sintering.

Abstract: A ceramic is fabricated by dispersing ceramic particles in a liquid, sedimenting the dispersion to remove large particles, and then changing its pH to flocculate the dispersed particles. The size distribution of the particles in each individual floc is similar to the size distribution of particles throughout the dispersion. The supernate is removed and the flocs are cast by centrifuging them into a mold. The cast flocs are dried and sintered to form the ceramic. To provide a multiphase ceramic, particles of two or more ceramics can be mixed together and flocced prior to centrifuging.

Abstract: A catalytic calorimeter measures the heat value of a gas and includes a chamber for receiving gas and air. A catalyst within the chamber causes the combustion of the gas and air, while a first thermocouple provides a signal indicating the temperature of the gas and air prior to combustion. A second thermocouple indicates the temperature of the catalyst, which is heated by an electrical resistance heater. A first temperature controller is connected to the second thermocouple and the heater for maintaining the catalyst at a predetermined temperature. A heat sink within the chamber absorbs heat from the products of the combustion of the gas and a third thermocouple indicates the temperature of the heat sink. A Peltier effect thermoelectric cooler is provided to remove heat from the heat sink. A second temperature controller connected to the third thermocouple and the cooler maintains the heat sink at a predetermined temperature.

Abstract: A thermal detector array includes a substrate layer with a pyroelectric layer attached to the substrate, a plurality of detector regions being defined in the pyroelectric layer by openings through the layer. An array of cavities in the substrate surface separates the detector regions from the surface. First and second electrodes are placed on opposite sides of each detector region or on a single side in a coplanar embodiment. The array is joined to a signal processing device by means of corresponding metallic contacts on the pyroelectric layer and the processing device.

Abstract: A solid state photon detector includes a semiconducting blocking layer with sufficiently low donor and acceptor concentrations that substantially no charge transport can occur by an impurity conduction mechanism. A semiconducting buffered layer is provided with a sufficiently high donor impurity concentration to create an impurity energy band and with a sufficiently high acceptor impurity concentration that an electron cannot be injected into and drift through the layer without recombining with ionized donors. A semiconducting active layer is positioned between the blocking and buffered layers with a sufficiently high donor concentration to create an impurity energy band. The acitve layer also includes a sufficiently low acceptor impurity concentration that a photogenerated electron can drift through the active layer without recombining with ionized donors.

Abstract: A semiconductor diode is designed to operate at a temperature where the thermal generation of free charge carriers is negligible. The diode includes a first semiconducting layer with a sufficient concentration of first conductivity type impurities to exhibit metallic type conductivity, a second semiconducting layer with a sufficient first conductivity type concentration to create an impurity energy band and with a second conductivity type impurity concentration less than half the first, and a blocking layer between the first and second layers with a sufficiently low impurity concentration that substantially no charge transport can occur by an impurity conduction mechanism. First and second ohmic contacts are deposited on the first and second layers opposite the blocking layer. The same types of layers are used to construct transistors.