Abstract: Heat conducting laminates and laminated heat conducting devices having at least one layer of metal and at least one layer of polymer matrix composite material having low-thermal-expansion reinforcing material distributed throughout and embedded therein. The coefficient of thermal expansion and the thermal conductivity of the laminated heat conducting devices are defined by the metal in combination with the polymer matrix material and the low-thermal-expansion reinforcing material in the laminate. The coefficient of thermal expansion and thermal conductivity of a heat conducting device can be controlled by bonding at least one layer of metal to at least one layer of polymer matrix composite material having low-thermal-expansion reinforcing material distributed throughout and embedded therein. In one embodiment, the laminated heat conducting device comprises a plurality of alternating layers of aluminum and epoxy resin having graphite fibers distributed throughout the epoxy resin.

Abstract: A truss structure for use in a gravity-free environment is disclosed together with methods and apparatus for constructing the same. The structure, characterized by high stiffness and a precise self-determined geometry and having a prism-form with square right cross section, is constructed from a plurality of substantially identical triangular frame elements. The truss structure may be manually constructed from a multi-row chain of interconnected elements or from a four row network of elements. The structure may also be constructed using an automatic method wherein individual frame elements are fed from four stack support and feed units to a holding fixture having a square cross section.

Abstract: A heat exchanger includes a porous cylindrical sleeve with a bore into which liquid coolant is admitted. The liquid permeates the sleeve but cannot leave the outer surface. A pipe surrounds the sleeve. The pipe has a cylindrical outer surface and an inner surface defining protrusions and vapor channels about the protrusions. The inner ends of the protrusions bear against the outer surface of the sleeve. A plurality of helical channels are helically arranged about and in thermal contact with the outer surface of the pipe. The ends of the helical channels are coupled to plenums. Each plenum is coupled by a pipe and a fluid disconnect to one end of a thermal loop including a heat source. Heat-laden vapor passes through the helical channels and is cooled to liquid. The heat is withdrawn into the pipe and passes through the protuberances to vaporize the liquid near the surface of the porous sleeve. The resulting vapor is collected and coupled to a condenser.

Abstract: A mast defined by three flexible longerons with cross elements coils into a canister. Extension and retraction are controlled by three axially oriented lead screws which engage protuberances spaced along the longerons. The lead screws are mutually synchronzied by an annular planet gear, and are driven by a spiroidal gear set. At a predetermined mast extension, motor drive is switched over for rotation of the mast rather than extension-retraction. The switch over is controlled by an actuator in the form of a movable guide element dimensioned to clear normal-sized protuberances but to be seized and carried by an oversize protuberance at the desired mast extension. The actuator is coupled to a lock which unlocks the annular gear to the canister so that motor drive results in mast rotation. An auxiliary lock allows re-locking of the canister to the support structure for allowing resumption of the mast extension-retraction mode.

Abstract: A method for welding two pieces includes juxtaposing the pieces and monitoring the temperature of the region to be welded. Energy is applied at a time rate sufficient to raise the temperature of the region to be welded at a rate exceeding a predetermined value. Once a predetermined temperature is reached, that temperature is held for a predetermined time. The rate of rise of temperature is 70% of the final or predetermined temperature in 20% of the predetermined time. After the weld is made, the rate of fall of the temperature exceeds a predetermined value. Quenching may be used to achieve the desired rate of fall.

Abstract: An electrical short-circuit for alternating-current (ac) microwave signals is physically positionable in direct response to an electrical bias control without an intermediary electromechanical converter. The electrically positionable short circuit includes at least first and second doped regions in a semiconductor, separated by a region in which the short circuit is formed between the doped regions by the bias. A first embodiment comprises discrete diodes connected between conductors at different locations, the discrete diodes having different forward junction voltages, so that varying the common bias voltage varies the number of conducting diodes and thus positions the short circuit in a stepwise manner.

Abstract: A switching power supply includes push-pull power switches driven by first and second conjunction gates. The conjunction gates are coupled to receive the output of a flip-flop, together with the antiphase outputs of a binary divider which divides down the output of the flip-flop. The flip-flop is driven recurrently by sync to enable one of the conjunction gates, and the binary divider steers the enablement alternately. When the output voltage or current crosses the design threshold, a comparator is triggered to produce a shut-down signal which is applied to the reset input terminal of the flip-flop to reset it. Delay in the flip-flop is avoided by also applying the shut-down signal to the conjunction gates. The maximum possible duty cycle is extended by initiating switch conduction at a predetermined short time after initiation of the sync pulse.

Abstract: An infrared imager includes an array of imager elements. Infrared radiation is focussed onto the array by a lens assembly including a plurality of lens elements. The imager array and the lens are within a cold box which includes an infrared-transparent window. For low noise, a spectrum-limiting filter is also located within the cold box, between the lens assembly and the window, at or within the pupil relief distance of the lens assembly. The pupil relief distance is extended by the use of at least one aspheric surface for one of the lens elements of the lens assembly. The mounting structure of the filter is the aperture stop for the infrared imager. The field of view may be reduced, if desired, without significant effect on the noise performance by use of a telescope including a second lens assembly optically identical to the first lens assembly, operated in conjunction with a confocal large-diameter lens assembly.

Abstract: A light-activated PIN diode switch arrangement is coupled to a source of direct voltage and to a load for control of the flow of load current. The PIN diode switch arrangement is connected so as to be electrically reverse-biased, so that no current flows therethrough. A source of light is coupled to the active portion of the PIN diode switch arrangement for rendering it conductive when flooded with light. Higher reverse voltage capability, higher operating speed and lower overall forward resistance are simultaneously achieved by a plurality of series-connected PIN diodes by comparison with a single large PIN diode.

Abstract: A chip layout system lays out chips including adjustable-shaped domains of standard cells and fixed-size macrocells. The system orders those standard cells which have interconnections into binary pairs or groupings of two. The binary pairs are grouped in higher and higher order groupings based upon evaluations of the area of the grouping and the sum of the lengths of the interconnections. All possible permutations of placement configuration including some rotations of various elements are further evaluated and the final placement is established on the basis of a minimum area, minimum interconnect length criterion. During the processing, the aspect ratios of the various domains and grouping of domains are adjusted to optimize their placement on the chip surface.

Abstract: An automated LSI chip layout arrangement includes automated layout of the power bus distribution network. A complete interlocking mesh of buses is run in routing channels lying between groups of circuits to be powered. Each segment of the mesh powering net which affects the chip size is tested to see if it can be removed without adversely affecting the power distribution. If it can be removed, the segment is deleted. The next segment which is critical to the size of the chip is then tested, and the process is continued. Those segments of the power bus distribution network which do not affect the size of the chip are not eliminated. Thus, a low-resistance power distribution bus network is guaranteed, and chip size is minimized.

Abstract: In a dc-to-dc converter, alternating current or pulsating direct current produced by a cyclically switched power supply passes through semiconductor rectifiers or diodes. The rectifiers may be subject to unwanted conduction characteristics attributable to charge storage, which may result in cyclical current spikes during normal operation. A current sensor is coupled to sense a current which includes the cyclical spikes. A controllable attenuator or gain element couples the sensed current in a feedback loop to shut down the converter in the event of an overcurrent. To reduce the possibility of shut-down due to the normal cyclical current spikes, the attenuator or gain element is cyclically switched so as to reduce the sensitivity to the current spikes when they occur.

Abstract: The effective capacitance of the floating diffusion in a floating-diffusion electrometer is modified to adjust electrometer sensitivity. This is done by changing the direct potential applied to a gate electrode proximate to the floating diffusion.

Abstract: An audio satellite communication system is provided using the ranging mode of a telemetry tracking and control (TT&C) system. The audio is placed on one of the ranging tone subcarriers of a TT&C ground station and received via the ranging tone subcarrier at other TT&C ground stations within the coverage area of the satellite omni-directional antenna.

Abstract: A reduced size waveguide directional coupler assembly includes a first rectangular waveguide which is adapted to receive signal at an input port. A conductive septum parallel with a broad wall of the rectangular waveguide divides the signal into two portions flowing in first and second channels within the first waveguide. The septum may be centered between the broad walls, in which case the two signal portions and channel dimensions are the same, or the septum may be off-center, resulting in dissimilar amplitudes of the two signal portions. The coupler also includes a second waveguide. Branch waveguides or other coupling apertures open from the first channel into the second waveguide. That energy not flowing to the second waveguide from the first channel may be routed to an independent output port, or may be recombined with the energy flowing in the second channel and routed to a combined output port.

Abstract: A P-channel field-effect transistor includes an inherent junction diode. As it is normally used, the inherent diode is back-biased and therefore effectively out of circuit. An uninterruptible power supply arrangement including primary and backup voltage sources supplies uninterrupted power to a load by way of two or more P-channel field-effect transistors connected so that their inherent diodes conduct to provide an OR function, independent of field-effect operation of the field-effect transistors. A control circuit controls the gate voltage relative to the source voltage of each transistor to selectively short-circuit the inherent diode of that one transistor which is connected to the power supply which is to energize the load. This reverse-biases the other inherent diodes and effectively removes the other power supply from the circuit, so that power for the load is drawn only from the selected power supply, there is no diode forward junction potential reducing the load voltage, and no excess dissipation.

Abstract: A solar array structure for use with satellites requiring large areas of solar arrays. Each array is a single continuous structure having continuous longitudinal members which in a stowed condition enable the panel to be wrapped around the satellite within its launch vehicle. In a deployed configuration, the longitudinal members are reconfigured to provide substantially increased stiffness in the direction of winding.

Abstract: A switch arrangement for interrupting signal flow on a microstrip transmission line includes an electromagnetically actuated conductive plunger extending through a hole in the dielectric plate on which the microstrip is formed. The strip conductor end adjacent the hole, and a spring conductive bridging element extends across the hole, fixed to one strip conductor and free to make contact with the other. The plunger is supported by a conductive diaphragm spring connected to the ground plane of the microstrip, thereby eliminating sliding contacts. When actuated, the plunger simultaneously lifts the bridging element free from the one strip conductor and short-circuits the other.

Abstract: A non-linear torque produced by an offset mass rotating on a shaft is balanced over 360.degree. of revolution by a lever arm mounted to the shaft extending in a direction opposite that of the offset mass and a spring means for generating a constant force in the direction of gravity at the opposite end of the lever arm.

Abstract: A power combiner includes an input power splitter driving a plurality (N) of amplifiers. The amplifier outputs have Z.sub.0 output impedance and are coupled by transmission (TX) lines of Z.sub.0 characteristic impedance to the junction point of a lossless power combiner. Short-circuiting switches located .lambda./4 from the junction power disconnect failed amplifiers from the combiner. According to the invention, a number M<N of the shorting switches are open during normal operation, so the impedance presented by the parallel TX lines at the junction of the combiner is Z.sub.0 /M. An impedance transformer associated with the combiner transforms the junction point impedance Z.sub.0 /M to Z.sub.0 at the combined output port, for example, by a .lambda./4 line having an impedance .sqroot.Z.sub.o.sup.2 /M.