Abstract: A superconductive junction device for fabricating Josephson integrated circuits is useful for replacing deposited thin-film resistors and for short-circuit device interconnections. Derived by "poisoning" a superconductive electrode or altering the barrier of a tunnel junction, the device displays controllable resistive properties at normal superconducting transition temperatures at substantial savings in the space occupied. Methods of fabricating the device using the selective niobium anodization process and ion implantation process are disclosed. When both upper and lower superconductive electrodes are poisoned, the device has linear properties whose resistance is identical to the normal resistance of unpoisoned junctions. Superconducting short circuits are readily obtained by oxygen ion implantation in thin film niobium electrodes.

Abstract: A superconductive junction device for fabricating Josephson integrated circuits is useful for replacing deposited thin-film resistors. Derived by "poisoning" a superconductive electrode of the Josephson junction, the device displays controllable resistive properties at normal superconducting transition temperatures at substantial savings in the space occupied. Methods of fabricating the device using the selective niobium anodization process and conventional lead alloy processes are disclosed. When both upper and lower superconductive electrodes are poisoned, the device has linear properties whose resistance is identical to the normal resistance of unpoisoned junctions.

Abstract: An apparatus for providing dynamic measurements of the grade of a road bed provides correction for accelerations of the carrying vehicle. A tilt transducer, responsive to both the angle and sense of inclination and to accelerations of the vehicle is used to measure the angle of displacement. The time rate of change of velocity signal derived from the motion of the vehicle is used to provide a signal corresponding to the vehicular acceleration. The acceleration signal level is adjusted to cancel acceleration sensed by the transducer, thereby providing an output reflecting the true angular grade reading.

Abstract: An optical 1.times.N switch uses a polarizing beam splitter cube and a reflector to separate an arbitrarily polarized incident light beam into polarized components which propagate along parallel paths. A polarization rotator is positioned in the path of the reflected component to rotate the plane of polarization of the light beam component propagating therealong to be coplanar with that of the undeviated light beam in the parallel path. The two beams are simultaneously or individually deflected by selectively activating the electrodes of a liquid crystal nematic reflector/transmitter array confined between prismatic bodies to emerge at one or more of a plurality of desired outputs. In a second embodiment, a second polarization rotator and polarizing beam combiner assembly re-establishes the initial polarization and the beams are thereby combined to emerge from one or more selected output terminals as an arbitrarily polarized light beam.

Abstract: An inclinometer providing a digital numerical readout includes a level sensor responsive to orientation and means for driving a liquid crystal display to indicate the inclination of a surface with a high degree of precision. Features include high stability with changes in battery voltage and surrounding temperature, a battery condition monitor, freedom from operational adjustments after the initial calibration, and partial blanking of the display to alert a user that the linear inclination limit has been reached. The direct reading digital readout permits ease of operation and a high degree of accuracy and repeatability. Circuitry is especially adapted for low power consumption.

Abstract: A method of fabricating gallium arsenide devices in which contact isolation is provided by a deep mesa step structure. Step coverage of deposited conductive films is facilitated by preferential orientation of the non-centrosymmetric crystal substrate and wet anisotropic etching that provides a sloped step. Problems of fine line definition of the Schottky anode contact in the photolithographic process are addressed by a two-step exposure of a single layer of thick photoresist followed by a chlorobenzene soak prior to development that ensures a retrograde resist profile needed for good lift-off of undesired evaporated metal. Mesas as deep as 7 .mu.m have been obtained, which permit the fabrication of monolithic planar mixer millimeter-wave diodes with low series resistance and reduced parasitic capacitance.

Abstract: A superconducting tunnel junction device having superconductive electrodes has a non-homogeneous barrier layer of amorphous semiconductive material, wherein when the central region is deposited in the presence of a gaseous atmosphere containing hydrogen there obtains a reduced density of localized states in the central region of the barrier so as to minimize leakage currents, resulting in improved current-voltage characteristics approximating an ideal tunnel junction device. The low leakage currents improve margins of Josephson logic circuits over tunneling barriers using uniformly deposited hydrogenated silicon with niobium electrodes, and increase the sensitivity of S-I-S microwave and millimeter wave length detectors and mixers. In a preferred embodiment, superconductive electrodes of niobium are conjoined with a tri-layer barrier using pure silicon adjoining the electrodes and a core of hydrogenated amorphous silicon. V.sub.

Abstract: A bi-directional driver system for an electrical load operable in response to two independent logic command signals provides a means for selecting the direction of current flow in the load when driven by the external command. A bridge circuit employs inputs to dual transistor switches operating in the saturated mode in series with the electrical load, cooperating with common emitter transistor linear amplifiers and diodes, and biased by the input logic signal so as to drive the load current in a predetermined direction. The circuit provides protection from undesired power supply current surges when logic command signals are applied to both inputs, and from transients due to failure of a saturated transistor switch at one input to cease conducting before the application of a command signal to the second input. Embodiments for inductive loads and annunciator lamps are described.

Abstract: A method for dry anisotropic etching of semiconductor material by a reactive gas infused in the presence of a low-pressure plasma discharge uses a photoresist mask superposed on a semiconductive film with the slope of the photoresist edges defined within a critical angular range to allow selective formation of a protective polymer film which prevents lateral etching of the edges of the photoresist and sidewalls of the film, while not inhibiting vertical etching, thereby allowing precision definition of the etched pattern. A novel technique to determine the conditions of the photoresist sidewall geometry necessary for polymer film formation and predictable etching behavior encapsulates the film in a thick layer of photoresist, which after cleaving the structure permits selectively etching the photoresist to expose and retain the polymer film without deformation.

Abstract: An improved display card holder, adapted for use in bulletin boards, as in arrival and departure boards for airlines, characterized by a retaining channel, in a base member, adapted to slideably receive a linear display card element, and a latch lever arm with a head extending through an opening in the base, which head is resiliently mounted and abuts against and arrests lateral motion of the display card element, so as to detachably secure the display card in the retaining track. A feature of the invention is that the operative elements of the latch are concealed and secured from tampering. A further feature of the invention is that its separate elements may be assembled or removed from the holder without the use of hand tools or fasteners.

Abstract: An improved gripper element for sports shoes, especially adapted for use on artificial turf. The gripper element or spike is recessed below a cover member urged outwardly by a captive resilient member until the wearer's weight is impressed upon his shoe, whereupon the spike is exposed to engage the turf. While used in plurality, individual gripper elements are readily detached and replaced. The resilient member can be optimized to suit the body weight of the wearer and type of athletic activity in which he engages.

Abstract: An apparatus for concentrating solar energy upon the surface of a collector containing a circulating heat transfer medium, whereby the radiant energy may be absorbed and utilized. The apparatus includes a housing supporting a hemispherical reflector for gathering incident solar radiation and directing the reflected energy upon an arcuate fluid-bearing tubular conduit, which is adjustable seasonally for optimizing collection of solar rays. The geometry of the combination is so arranged that the reflected energy traverses the collector in response to the angle of solar rays falling on the concentrator without need for diurnal tracking.