Abstract: Chemically stable polymers in aqueous alkaline solutions are dissolved in a strongly polar solvent, thoroughly dispersed from this solvent into and throughout the interstices of porous inorganic fabrics and subsequently separated from said solvent by precipitation to provide a homogeneous reinforcement of the structural properties of said fabrics.

Abstract: A laser which self-corrects for distortions introduced into the laser beam wavefronts by aberrations and time-varying phenomena internal to the laser. The improved laser includes a partially transmissive first reflecting element, an aperture stop, a lasing medium and a nonlinear phase conjugate reflecting device as the second reflecting element. During laser operation, aberrated wavefronts impinging upon the second reflecting element are reflected as the phase conjugate waveform thereof. The aperture stop restricts laser operation to the fundamental mode which allows only corrected, unaberrated waves to pass through the aperture stop and to subsequently exit the laser. Four embodiments are described utilizing stimulated Brillouin scattering (SBS), four-wave mixing, three-wave mixing and photon echo devices as the second reflecting element.

Abstract: A low cost improved adjustable mirror mount is disclosed. The adjustable mirror mount includes an inner cylindrical member one end of which is sealed to a laser tube and a mirror is mounted to the other end. The midsection circumference of the inner cylindrical member may be thinner in order that it be easily deflected about its axis. An outer cylindrical member is coaxial to and surrounds the inner cylindrical member. A plurality of adjustment screws are radially disposed at the end of the outer member for deflecting the inner cylindrical member and the mirror. Thus, the angle of the mirror to the axis of the laser discharge tube is very accurately adjusted.

Abstract: A charge coupled device (CCD) transversal filter (TVF) having an improved electrode configuration and connecting arrangement which minimizes the noise that is added to the signal to provide a relatively high amplitude output signal and a relatively high output signal-to-noise ratio. The CCD transversal filter operates with the weighting coefficients determined by the one sided width of the electrodes and with one end of the split electrodes coupled to the output and the other ends of the split electrodes coupled to a reference voltage source. When some of the weighting coefficients of the desired impulse response are negative the output ends of the weighting electrodes are selectively connected to either the inverting or noninverting common connections of a differential amplifier in turn providing the transversal filter output signals. For a single polarity impulse response, all of the electrodes are coupled to an output arrangement without requiring an inversion.

Abstract: Regenerator for a cryogenic system has lead sphere 58 packing and has grooves 54 and 56 in the regenerator walls to prevent gas bypass. Felt packing 66 between screens 64 and 68 causes continued compression of the regenerator packing as it changes size due to temperature changes. Gas spaces between the regenerator spheres is maintained low and regenerator sphere damage due to high intersphere loading is minimized.

Abstract: A class of two-terminal active networks which simulate low-noise temperature resistors is disclosed. A single field effect transistor or other suitable amplifier comprises the active element of the network. A dual transformer feedback arrangement or a single transformer feedback arrangement comprises the remainder of the circuit. Either positive or negative simulated resistors can be obtained with a wide range of equivalent resistance values and effective noise temperatures.

Abstract: Screw expander is employed in closed cycle steam power cycle and employs heat extraction during steam expansion to improve Rankine cycle efficiency.

Abstract: A quantizer network is disclosed for decoding an analog signal and providing a four-bit digital output. The analog input signal is divided or quantized into sixteen discrete voltage ranges and applied to sixteen differential amplifiers. Each amplifier has a different reference which must be exceeded before it provides an output signal. The sixteen differential amplifiers are connected to nine latch networks which respond to the signals from the amplifiers and provide a cyclic code in response thereto. The latch networks are connected to a network of logic gates which decode the cycle code into a four-bit digital output signal. The output signals from the logic gate network are applied to output stages which extend the valid time of the output signal from the logic gates.

Abstract: Narrow-band optical filters are disclosed utilizing a birefringent crystal exhibiting a change in sign in birefringence at a predetermined wavelength and relying upon wave coupling between ordinary and extraordinary polarizations of light at or near the predetermined wavelength. The crystal is disposed along the light path between appropriately oriented polarizers, and a dc electric field is applied to the crystal either parallel or perpendicular to the light path. The dc electric field produces the aforementioned wave coupling for light at the center wavelength of the filter which normally is equal to the predetermined wavelength. The filter center wavelength may be displaced from the predetermined wavelength by employing a spatially periodic electric field.

Abstract: Helical slow-wave structure assemblies including a helical dielectric supporting member are disclosed along with methods for fabricating such assemblies. After the slow-wave structure helix is wound on a mandrel, a masking helix is coaxially wound about the slow-wave structure helix in the same sense as the slow-wave structure helix over the helical space between turns of the slow-wave structure helix and in overlapping relationship with portions of adjacent turns of the slow-wave structure helix. The supporting helix is formed by plasma spraying dielectric material into the helical space between turns of the masking helix. The dielectric material is ground to a predetermined radial dimension, and the mandrel and the masking helix are removed. By utilizing a masking helix of tapered width, a dielectric supporting helix of tapered width may be fabricated to provide a slow-wave structure assembly with a tapered phase velocity.

Abstract: The specification describes a means and method for mixing millimeter wave RF energy of one chosen transverse electric (TE) waveguide mode with a local oscillator signal of another chosen TE waveguide mode, and such mixing is accomplished by applying those RF and local oscillator signals to a pair of reverse poled and parallel connected mixer diodes. These mixer diodes are connected at a chosen location within a rectangular waveguide and between top and bottom walls thereof and are symmetrically spaced across the width of the waveguide with respect to the center or a/2 location in the guide, with "a" being the width dimension in the guide. An IF output signal is derived at a common output node for the mixer diodes.

Abstract: A phased array antenna system is disclosed for scanning a narrow beam over a limited angular sector with near optimum performance while using the minimum number of active elements. An input corporate feed is coupled to a "thinned" array of phase shifters. Each phase shifter is coupled to one of a plurality of lossless periodic matrix sub-array feed networks. Radiating elements are coupled in periods such as three elements per period. The output of each phase shifter is selectively coupled to the array of radiating elements within its period and to elements in adjacent periods as well. Such an array permits a plurality of overlapping main beams having low side lobes and grating lobes.

Abstract: There is herein described a device useful to store a frame of low-intensity optical information over a wide spectral range or useful as a real-time light valve in visible to infrared conveter application. The device basically includes either a storage mode liquid crystal or a dynamic scattering or a field-effect liquid crystal, and a semiconductor diode array substrate wherein an insulating film with an array of conducting windows separates the liquid crystal from an active region in the substrate. A separate diffused junction is disposed in the active region adjacent each of the windows, the latter being adapted to both reflect incident light energy and conduct electrical current.

Abstract: A ball bearing having a metal inner and outer ring, each ring having at least one land, and the bearing having metal balls disposed between the rings to form load bearing metal-to-metal interfaces. A ball bearing retainer disposed between the rings of the bearing, the retainer comprising rigid members supporting a soft, flexible, highly porous annular body having ball pockets for receiving the bearing balls, and having at least one projection on at least one circumferential surface thereof. The ball pockets are sized to have an interference fit with the balls, and the projection is made to be in contact with at least one land of the inner or outer ring. The annular body is made of a porous foamlike material capable of absorbing up to eighty percent by volume of a liquid lubricant, such as oil, and being capable of supplying a suitably large fraction of the stored lubricant to the bearing.

Abstract: The method and apparatus for processing bipolar coherent sidelooking radar data to achieve continuous real time synthetic array mapping in the form of focused line-by-line imagery. Received radar data is correlated such that a number of subarrays are vectorially combined with appropriate quadratic phase corrections to continuously form the total synthetic array. Each subarray is accumulated in a recirculating (feedback) channel which applies a linear phase correction and amplitude weighting, which in turn reduces the arithmetic operations required to form the array. The subarrays are updated by continuously subtracting out the oldest data and adding new data to yield continuous line-by-line imagery. Alternate accumulator and feedback channels are employed in an interleaved fashion to minimize the buildup of "round-off" errors which result from digital multiplications. The invention is adaptable to all-range-focusing and operation at various pointing angles.

Abstract: A liquid crystal light valve which uses the transfer of charge carriers representing a plurality of signals from a CCD array to a liquid crystal light modulated display medium. The signal charge is extracted from the back side of the CCD by driving the CCD clock voltages to zero and allowing the charge to diffuse to the back side where it is collected in a charge depleted region formed by a reverse biased diode and injected into the interface layers of a liquid crystal display medium.

Abstract: Electron beam microfabrication apparatus has spherically concave photocathode pattern 40 which when excited produces patterned electron beam 48 which is accelerated by electrode 44 and magnetically focused by magnet 58 to impinge as a demagnified patterned field 60 on a photoresist carrying semiconductor wafer 36 mounted of wafer holder 34.

Abstract: A number of alkyl and alkoxy-substituted ortho-cyanophenyl biphenylcarboxylate esters have been prepared for use as components for nematic liquid crystal mixtures which can be used in homeotropically aligned, field effect display devices or in dynamic scattering displays.These materials have large negative dielectric anisotropies and high birefringence.

Abstract: There is disclosed a polarizer particularly suited for use in the infrared wavelengths which comprises a wire grid polarizer in optically cascaded relationship with a Brewster's Angle Polarizer. Not only do the extinction ratios of the optically cascaded polarizers multiply to provide higher extinction ratios at these wavelengths, but also the reflective mirror properties of the wire grid polarizers can be used in combination with the known optical properties of Brewster Polarizers to provide a combined device which optimizes both the extinction ratios achieved and the balance between the reflection and recombination problem of the system on the one hand and the offset or beam walking problem on the other hand in a manner to provide optical characteristics which are not achievable from any simple combinations of either type of polarizer alone.

Abstract: A scene tracker for use with imaging or quasi-imaging sensors such as TV cameras, FLIRS, millimeter-wave scanners, or the like is disclosed. Specifically, the invention is concerned with a form of correlation tracking. At the start of a track mode, part or parts of a scene are stored in a memory. Every subsequent video scan is then compared with the scene or parts of the scene stored in memory to find the "best match" between live data and stored data. This process generates signal output proportional to horizontal and/or vertical translations of the scene. Besides pure translation, the disclosed scene tracker is capable of tracking an original aim point in the presence of scene rotation, scene growth (zooming), scene reduction (dezooming), distortion, and/or partial scene obscuration.