Abstract: High T.sub.c superconducting compounds are made by forming a reaction mixture of the oxides of Sr, Cu, Ca and Tl, compressing these into a hardened body, and placing the hardened body into a container. The container is then evacuated and sealed. The hardened body is heated under pressure until the oxides of Sr, Ca, Cu, and Tl react to form a superconducting compound.

Abstract: In an interferometer apparatus used for monitoring an object surface, the apparatus having a source of coherent light, a beam splitter for dividing the coherent light into a reference beam and an object beam, another beam splitter for dividing the object beam into two separate portions, and a light detector for detecting light interference, comprising an externally-pumped phase-conjugate mirror working in conjunction with a self-pumped phase-conjugate mirror. The externally-pumped phase-conjugate mirror receives the reference beam, receives one portion of the object beam, and reflects the received portion of the object beam to the detector as a first phase-conjugate beam. The self-pumped phase-conjugate mirror receives a second portion of the object beam and reflects the received portion of the object beam to the detector as a second phase-conjugate beam.

Abstract: An antiresonant nonlinear mirror to replace one mirror of a laser for passive modelocking of the laser, the antiresonant nonlinear mirror comprising: a beam splitter for coupling the mirror to a laser cavity; a mirror arrangement for defining an optical ring with the beam splitter in which two light beams produced by the beam splitter in response to a light beam from the laser cavity can counterpropagate around the ring; an intensity dependent anisotropic nonlinear element disposed within the ring; and a polarization sensitive element disposed within the ring for adjusting the birefringence thereof to produce spontaneous modelocking in the coupled laser cavity.

Abstract: A low pressure, low energy measuring device for indirectly and non-invasiy measuring the pressure of a gaseous medium in a sealed system, such as gas discharge lamp, is disclosed. The measuring device and method measures the luminance of an externally-induced, high-frequency glow discharge of a gas in the lamp by non-invasive means. Comparison of the measured luminance with calibrated luminance vs. pressure data provides the pressure for the gas. In one embodiment, the components of the measuring device form a stand-alone unit useful for testing multiple sealed systems. In another embodiment, certain components of the device are integrated into the lamp's discharge system to facilitate measurement in the field. A separate peripheral unit is required with this latter embodiment.

Abstract: A neural net, and method of using the net, to solve ill-posed problems, such as deconvolution in the presence of noise. The net is of the Tank-Hopfield kind, in which input to the signal net is a cross entropy regularizer.

Abstract: A process is provided for forming a glass fiber having one or more metal aments in its core. In the process, a metal rod or particles of a metal or semiconducting material optionally mixed with glass powder is introduced into a hollow glass tube closed at one end, and the tube is evacuated while the closed end is heated and a fiber drawn therefrom. The resultant glass fiber contains one or more discrete filaments of the metal or semiconducting material.

Abstract: Nanometer thick vertical metallic structures are fabricated on a substrate by depositing a metallic layer on a substrate surface on which one or more buttresses are formed, etching the metallic layer to expose the horizontal surfaces of the substrate and the buttresses, and etching the substrate to remove the buttresses, thereby producing vertical structures on the substrate. The metallic layer is formed by thermal decomposition of a volatile metal-containing precursor gas in the presence of a carrier gas at low pressure, unlike that in conventional CVD reactors. The metallic layer thus formed has a grain size which is fraction of the thickness of the vertical structure.

Abstract: This invention relates to a semiconductor substrate having a porous surface nd to the amperometric receptor-based sensors formed with the substrate. More specifically, this invention pertains to the substrate in the form of a bipolar junction transistor having a porous hydrophilic surface directly on its base wherein the surface forms a support for an amperometric sensor. The invention also pertains to the methods of making and using the substrate and sensor.

Abstract: In a lasing dye sensor system, a stream of lasing dye freeflows across an ea open to the atmosphere. A chemical reaction between contaminants in the atmosphere and the lasing dye result in the change of emission spectra of the lasing dye. The change in emission spectra is detected and provides an improved apparatus and method for detecting low concentrations of chemical vapors in the atmosphere.

Abstract: Method and apparatus for improving detection ranges of a pulsed radar sys wherein electromagnetic return signal data in range cell order is doppler filtered, digitized and stored in doppler memory channels over multiple scans of an azimuth. The digital doppler data in each doppler memory channel is scan-to-scan integrated over a predetermined number of scans to produce target displays for each possible velocity. The target displays are stored in a velocity memory, which is partitioned into velocity channels, each velocity channel corresponding to one possible velocity. A selector selects the target display having the largest total magnitude as a display signal. The scan-to-scan integrated target displays are not subject to collapsing losses since only target signals plus noise signals will be stored in the doppler memory channel corresponding to the target's velocity.

Abstract: A tunable solid state laser for producing a laser emission at any desired w or high laser gain transition in a predetermined range of wavelengths is disclosed. The tunable solid state laser comprises: a laser cavity defined by a first reflective element and an output coupler reflective element to form a reflective path therebetween; a laser crystal disposed in the laser cavity; means for optically exciting the laser crystal to produce a laser emission in the predetermined range of wavelengths; a tunable element disposed in the laser cavity between the laser crystal and one of the reflective elements for tuning the laser emission to any desired laser transition in the predetermined range of wavelengths; and a plurality of optical plates oriented at Brewster's angle in the reflective path in the laser cavity for suppressing oscillation of undesired wavelengths within the laser cavity, the optical plates being transparent to the laser emission over the predetermined range of wavelengths.

Abstract: A substantially single phase superconducting composition is formed from a of 1:2:3 molar ratio of fine powders of a superconducting rare earth oxide, CuO, and BaCo.sub.3. The mixed powders and shaped articles formed from the mixed powders are calcined, sintered, and cooled in an oxygen containing atmosphere. The cooling step is done slowly to convert the sample to the orthorhombic structure and to improve the superconducting properties. The article formed is a substantially single phase superconducting composition.

Abstract: A high temperature superconducting coating of material oxide is produced by melting the metal oxide mixture, dipping a substrate, e.g. a platinum wire, in the metal oxide melt, withdrawing the substrate with a layer of metal oxide coated thereon, slowly cooling the metal oxide coating to avoid thermal shock and hot cracking, and post-annealing the metal oxide coating.

Abstract: A system and method for minimizing polarization-induced phase noise in an interferometric fiber sensor is disclosed.

Abstract: A photoconductive semiconductor device having a source, a drain, and a photosensitive channel therebetween. The channel has a surface layer that is highly doped with respect to the remainder of the channel, compensating at least in part for the channel's surface depletion layer. In this manner, the photosensitivity of the device is increased without disproportionately increasing wasted dark current. In a preferred embodiment, the additional doping of the channel's surface layer is done by ion implantation, and the device is a monolith formed of gallium arsenide.

Abstract: A tunneling tip piezo is incorporated into various devices for measuring effect of changes in environmental conditions (i.e., temperature, pressure, magnetic and electrical fields, etc) upon a material by sensing minute changes in the dimensions of the surface. The devices may be used to detect changes in environmental conditions or to determine physical properties of a material.

Abstract: A multiport microwave multiplexer having components which are log-periodically scaled structures is shown and described. Circuit parameter values and characteristic frequencies are determined and a first output port is linked by a constant ratio to corresponding quantities that define the response of other networks. A capacitively end-coupled channelizer filter is used for each channel of the multiplexer.

Abstract: A new class of lubricants based on the general features of archaebacterial lipids but not limited to lipids solely extracted from archaebacteria is described. These lubricant/additive molecules have the following features: bipolarity, ether bonds and branched biphytanyl chains. They can be double chained or single chained. This new class has the potential to be highly thermally and chemically stable due to the above mentioned features.

Abstract: Methods for accurately measuring the range between two platforms with relative motion between them using a stable clock located on each platform. A series of pulses are sent from one platform to the other at times known to each platform by prearrangement, the arrival times measured, and statistical methods used to calculate a correction from the clocks to bring them into greater synchronization, thus allowing highly accurate determination of the range between the two platforms.

Abstract: A surface floating buoy has an antenna attached to a linkage system which pivots about the floating buoy. The linkage system is attached to a counterweight such that the antenna is maintained at a desired vertical position with respect to the surface of a body of water by pantographic action. The floating buoy contains a hollow cavity of sufficient size to hold the linkage system antenna and counterweight prior to deployment in a body of water. Upon deployment in the water, gravitational forces on the counterweight and linkage system cause the system to be deployed. The invention may also include a servo feedback system for more accurately positioning the antenna at its desired position.