Abstract: A real-time, pre-detection optical dynamic range compression system uses a photorefractive crystal, such as BaTiO.sub.3 or LiNbO.sub.3, in which light induced scattering from crystal inhomogeneities of the optical input occurs as a nonlinear function of the input intensity. The greater the intensity, the faster random interference gratings are created to scatter the incident light. The unscattered portion of the optical signal is therefore reduced in dynamic range over time. The amount or range of dynamic range compression may be controlled by adjusting the time of application of the unscattered crystal output to the photodetector with regard to the time of application of the optical input to the crystal.

Abstract: An optical system for auto-associative and hetero-associative recall utilizing Hamming distance as the similarity measure between a binary input image vector V.sup.(k) and a binary image vector V.sup.(m) in a first memory array using an optical Exclusive-OR gate for multiplication of each of a plurality of different binary image vectors in memory by the input image vector. After integrating the light of each product V.sup.(k) .times.V.sup.(m), a shortest Hamming distance detection electronics module determines which product has the lowest light intensity and emits a signal that activates a light emitting diode to illuminate a corresponding image vector in a second memory array for display. That corresponding image vector is identical to the memory image vector V.sup.(m) in the first memory array for auto-associative recall or related to it, such as by name, for hetero-associative recall.

Abstract: Apparatus for characterizing the magnetic field of a device under test includes a device for nullifying the ambient magnetic field in a test environment area with a constant applied magnetic field, a device for rotating the device under test in the test environment area at least nearly through a complete circle, a device for sensing the magnetic field at a sensor location which is along the circumference of rotation as a function of the rotation angle for successive ones of a set of predetermined orientations of the device under test to obtain a profile of the magnetic field at the sensor location as a function of the rotation angle for each one of the predetermined orientations, a memory for storing the profiles, and a processor coupled to the memory for characterizing the magnetic field of the device from the magnetic field profiles thus obtained.

Abstract: The invention relates to a method and apparatus for frequency spectrum analysis of an unknown signal in real time based upon integration of 1-bit samples of signal voltage amplitude corresponding to sine or cosine phases of a controlled center frequency clock used to time the samples taken, but preferably corresponding to both sine and cosine phases of the center frequency clock which is changed after each integration interval to sweep the frequency range of interest in steps. Integration of samples during each interval is carried out over a number of cycles of the center frequency clock spanning a number of cycles of an input signal to be analyzed. The invention may be used to detect the frequency of at least two signals simultaneously.

Abstract: A Joule-Thomson cryogenic refrigeration system capable of achieving high temperature stabilities in the presence of varying temperature, atmospheric pressure, and heat load is provided. The Joule-Thomson cryogenic refrigeration system includes a demand-flow Joule-Thomson expansion valve disposed in a cryostat of the refrigeration system. The expansion valve has an adjustable orifice that controls the flow of compressed gas therethrough and induces cooling and partial liquefaction of the gas. A recuperative heat exchanger is disposed in the cryostat and coupled to the expansion valve. A thermostatically self-regulating mechanism is disposed in the cryostat and coupled to the J-T expansion valve. The thermostatically self-regulating mechanism automatically adjusts the cross-sectional area of the adjustable valve orifice in response to environmental temperature changes and changes in power dissipated at a cold head.

Abstract: A method for determining Richardson Number, Ri, or its reciprocal, RRi, for clear air turbulence prediction using measured potential temperature profiles and determining the vertical gradient of potential temperature, d.theta./dz. Wind vector from the aircraft's instrumentation versus potential temperature dw/d.theta. is determined and multiplied by d.theta./dz to obtain dW/dz. Richardson Number or its reciprocal is then determined from the relationship ##EQU1## for use in detecting a trend toward a threshold value for the prupose of predicing clear air turbulence. Other equations for this basic relationship are disclosed together with the description of a method for combining of other atmospheric observables using multiple regression techniques to produce improved warnings of clear air turbulence.

Abstract: A sensor assembly to be carried on an aircraft or spacecraft which will travel along an arbitrary flight path, for providing an image of terrain over which the craft travels. The assembly includes a main linear sensor array and a plurality of auxiliary sensor arrays oriented parallel to, and at respectively different distances from, the main array. By comparing the image signals produced by the main sensor array with those produced by each auxiliary array, information relating to variations in velocity of the craft carrying the assembly can be obtained. The signals from each auxiliary array will provide information relating to a respectively different frequency range.

Abstract: A method and apparatus are disclosed for edge phasing an array of segments in a segmented primary telescope mirror using white light from a far field source and starting with the inner edge of each segment in the first ring of segments. The segments are individually phased for zero piston and tilt error with respect to the edge of a reference surface in the open center position of the telescope mirror, and proceeding from ring to ring by edge phasing one edge of each segment in each subsequent ring with an edge of a segment in a preceding ring that has been edge phased. After edge phasing of all segments in the telesope mirror array has been completed, full surface phasing can be achieved using a conventional Shack-Hartmann technique followed by finding the RMS best fit for each segment of the mirror array.

Abstract: The conductivity is increased an order of magnitude and interfacial charge transfer resistance is substantially decreased by incorporating a minor amount of 12-Crown-4 ether in a polyethylene oxide-lithium salt solid electrolyte film.

Abstract: A computer-simulated cortical network computes the visibility of shifts in the direction of movement and computes: 1) the magnitude of the position difference between the test and background patterns, 2) localized contrast differences at different spatial scales analyzed by computing temporal gradients of the difference and sum of the outputs of paired even- and odd-symmetric bandpass filters convolved with the input pattern and 3) using global processes that pool the output from paired even- and odd-symmetric simple and complex cells across the spatial extent of the background frame of reference to determine the direction a test pattern moved relative to a textured background. The direction of movement of an object in the field of view of a robotic vision system is detected in accordance with non-linear Gabor function algorithms. The movement of objects relative to their background is used to infer the 3-dimensional structure and motion of object surfaces.

Abstract: This is a fully parallel analog backpropagation learning processor which comprises a plurality of programmable resistive memory elements serving as synapse connections whose values can be weighted during learning with buffer amplifiers, summing circuits, and sample-and-hold circuits arranged in a plurality of neuron layers in accordance with delta-backpropagation algorithms modified so as to control weight changes due to circuit drift.

Abstract: Disclosed is a method for fabricating an edge geometry superconducting tunnel junction device comprising two niobium nitride superconducting electrodes (14,28) and a magnesium oxide tunnel barrier (24) sandwiched between the two electrodes. The NbN electrodes are preferably sputter-deposited, with the first NbN electrode deposited on an insulating substrate maintained at about 250.degree. to 500.degree. C. for improved quality of the electrode.

Abstract: An edge defined geometry is used to produce very small area tunnel junctions (30) in a structure with niobium nitride superconducting electrodes (14, 28) and a magnesium oxide tunnel barrier (24). The incorporation of an MgO tunnel barrier with two NbN electrodes results in improved current-voltage characteristics, and may lead to better junction noise characteristics. The NbN electrodes are preferably sputter-deposited, with the first NbN electrode deposited on an insulating substrate maintained at about 250.degree. to 500.degree. C. for improved quality of the electrode.

Abstract: For the growth of strain-layer materials and high quality single and multiple quantum wells, the instantaneous control of growth front stoichiometry is critical. The process of the invention adjusts the offset or phase of MBE control shutters to program the instantaneous arrival or flux rate of In and As.sub.4 reactants to grow InAs. The interrupted growth of first In, then As.sub.4, is also a key feature.

Abstract: The invention relates to a stabilization device for stabilizing dendritic web seed buttons during initiation of crystal growth from a float zone melt. The invention includes angular maintenance means for maintaining a constant angular orientation between the axis of a growth initiation seed and the upper surface of a web button during withdrawal of the web button from the melt. In the preferred embodiment, the angular maintenance means includes an adjustable elevation tube which surrounds the seed, the weight of which may be selectively supported by the seed button during web button withdrawal.

Abstract: III-V films are grown on large automatically perfect terraces of III-V substrates which have a different lattice constant, with temperature and Group II and V arrival rates chosen to give a Group III element stable surface. The growth is pulsed to inhibit Group III metal accumulation to low temperature, and to permit the film to relax to equilibrium. The method of the invention 1) minimizes starting step density on sample surface; 2) deposits InAs and GaAs using an interrupted growth mode (0.25 to 2 mono-layers at a time); 3) maintains the instantaneous surface stoichiometry during growth (As-stable for GaAs, In-stable for InAs); and 4) uses time-resolved RHEED to achieve aspects (1)-14 (3).

Abstract: A shared system for robot control including integration of the human and autonomous input modalities for an improved control.Autonomously planned motion trajectories are modified by a teleoperator to track unmodelled target motions, while nominal teleoperator motions are modified through compliance to accommodate geometric errors autonomously in the latter. A hierarchical shared system intelligently shares control over a remote robot between the autonomous and teleoperative portions of an overall control system. Architecture is hierarchical, and consists of two levels. The top level represents the task level, while the bottom, the execution level.In space applications, the performance of pure teleoperation systems depend significantly on the communication time delays between the local and the remote sites. Selection/mixing matrices are provided with entries which relfect how each input's signals modality is weighted.

Abstract: The invention is a linear actuator that operates under the principle that like charges repel and opposite charges attract. The linear actuator consists of first and second pairs of spaced opposed conductors where one member of each pair of conductors is attached to a fixed member, and where the other member of each pair of conductors is attached to a movable member such as an elongated rod. The two pairs of spaced conductors may be provided in the form of two spacedly interwound helical vanes where the conductors are located on the opposite sides of the two helical vanes. One helical vane extends inwardly from a housing and the other helical vane extends outwardly from an elongated rod. The elongated rod may be caused to move linearly with respect to the housing by applying appropriate charges of like or opposite polarity to the electrical conductors on the helical vanes.

Abstract: A system for monitoring the configuration of a surface (e.g., a segmented parabolic surface) using orthogonally placed retroreflectors at sets of points A, B and C dispersed throughout the surface with a stationary halfwave plate HWP in the front of the one retroreflector at a corner point C and a rotating halfwave plate RHWP over a source of linearly polarized coherent light, thereby causing the direction of linear polarization to continuously rotate through 360.degree. and causing light returned by the retroreflector at point C to be continuously phase shifted through 360.degree. relative to light returned by retroreflectors at points A and B. The returned light from each set of points A. B and C is focused onto a bed-of-nails (BON) phase grating diagonally oriented with respect to the orthogonal orientation of the incident beams from retroreflectors A, B and C, thereby causing overlap in the light from points A and C and from points B and C to produce interferometric signals AC and BC.

Abstract: A self-adjusting orifice for fluids nozzle includes a membrane constructed of a single piece of flexible or elastic material. This flexible material is shaped to fit into the outlet of a nozzle. The body of the membrane has at least two flow channels, from one face to the other, which directs two streams of water to cross at the opening of the nozzle or at some point beyond. The elasticity and thickness of the membrane is selected to match the range of expected pressures and fluid velocities. The orifice may have more than two flow channels, as long as they are aligned adjacent to one another and directed towards each other at the exit face. In a three orifice embodiment, one is directed upward, one is directed downward, and the one in the middle is directed forward. In this embodiment all three fluid streams intersect at some point past the nozzle opening.