Abstract: A variable energy, high flux atomic oxygen source (10) comprising means (48) for producing a high density beam of molecules which will emit O.sup.- ions when bombarded with electrons; means (44) for producing a high current stream of electrons at a low energy level passing through the high density beam of molecules to produce a combined stream (54) of electrons and O.sup.- ions; means (32) for accelerating the combined stream to a desired energy level; means (12) for producing an intense magnetic field to confine the electrons and O.sup.- ions; means (56, 58) for directing a multiple pass laser beam (62) through the combined stream to strip off the excess electrons from a plurality of the O.sup.- ions to produce ground-state O atoms within the combined stream; electrostatic deflection means (68, 70) for deflecting the path of the O.sup.- ions and the electrons in the combined stream; and, means (78) for stopping the O.sup.

Abstract: A clock pulse generator for decoding pulse position modulation in an optical communication receiver is synchronized by a delay tacking loop which multiplies impulses of a data pulse by the square-wave clock pulses from the generator to produce positive impulses when the clock pulse is of one level, and negative impulses when the clock pulse is of another level. A delay tracking loop integrates the impulses and produces an error signal that adjusts the delay so the clock pulses will be synchronized with data pulses. A dead-time .tau..sub.d provided between data pulses of an interval .tau..sub.p in the data pulse period .tau.. When synchronized, the average number of positive impulses integrated will equal the average number of negative impulses over the continuous stream of data pulses.

Abstract: A compact hydride absorption refrigeration system with few moving parts for 10.degree. Kelvin operation is disclosed and comprises liquid hydrogen producing means in combination with means for solidifying and subliming the liquid hydrogen produced. The liquid hydrogen is sublimed at about 10.degree. Kelvin. By using a symmetrical all hydrogen redundant loop system, a 10.degree. Kelvin refrigeration system can be operated for many years with only a fraction of the power required for prior art systems.

Abstract: A multijunction silicon solar cell of high efficiency is provided by providing a tunnel junction between the solar cell junctions to connect them in series, where the tunnel junction is comprised of p.sup.+ and n.sup.+ layers of high band-gap III-V or II-VI semiconductor materials that match the lattice structure of silicon, such as GaP (band-gap 2.24 eV) or ZnS (band-gap 3.6 eV), each of which has a perfect lattice match with silicon to avoid defects normally associated with lattice mismatch.

Abstract: A tank tread assembly having adjacent tank tread segments joined by a link bearing tapered pins retained by clips inserted through the tread shells perpendicular to the axes of the pins and having highway pads attached by a release rod bearing tapered, grooved cams which interlockingly engage tabs inserted into the tread shells.

Abstract: Examination of microstructures of LSI and VLSI devices is facilitated by employing a method in which the device is photographed through a darkfield illumination optical microscope and the resulting negative subjected to inverse processing to form a positive on a photographic film. The film is then developed to form photographic prints or transparencies which clearly illustrate the structure of the device. The entire structure of a device may be examined by alternately photographing the device and selectively etching layers of the device in order to expose underlying layers.

Abstract: The purity and perfection of a semiconductor is improved by depositing a patterned mask (12) of a material impervious to impurities of the semiconductor on a surface (14) of a blank (10). When a layer (40) of semiconductor is grown on the mask, the semiconductor will first grow from the surface portions exposed by the openings (16) in the mask (12) and will bridge the connecting portions of the mask to form a continuous layer (40) having improved purity, since only the portions (42) overlying the openings (16) are exposed to defects and impurities. The process can be reiterated and the mask translated to further improve the quality of grown layers.

Abstract: A MOSFET structure having a biased gate covered with an insulator of such a thickness as to render the structure capable of giving a measure of accumulated charge and usable in a stacked structure as a particle spectrometer.

Abstract: A fluidic sensor providing a differential pressure signal proportional to the angular velocity of a rotary input. In one embodiment the sensor includes a fluid pump having an impeller coupled to a rotary input. A housing forming a constricting fluid flow chamber is connected to the fluid input of the pump. The housing is provided with a fluid flow restrictive input to the flow chamber and a port communicating with the interior of the flow chamber. The differential pressure signal measured across the flow restrictive input is relatively noise free and proportional to the square of the angular velocity of the impeller. In an alternative embodiment, the flow chamber has a generally cylindrical configuration and plates having flow restrictive apertures are disposed within the chamber downstream from the housing port. In this embodiment, the differential pressure signal is found to be approximately linear with the angular velocity of the impeller.

Abstract: A method and apparatus for detecting submillimeter or IR radiation is disclosed. A rare gas, such as xenon, is supplied at its ground state via a pressurized cylinder and an adjustable leak valve into a cryogenically-cooled detection area. The ground state of xenon is double-photon excited to a particularized level of the Rydberg series by a resonance lamp and a laser. The doubly-excited gas is then further excited by the radiation to be measured. A field ionization and an ion measurement indicative of the radiation intensity is achieved.

Abstract: A macrocrystalline or single crystal semiconductive material is formed from a primary substrate including a single crystal or several very large crystals of a relatively low-melting material. This primary substrate is deposited on a base such as steel or ceramic, and it may be formed from such metals as zinc, cadmium, germanium, aluminum, tin, lead, copper, brass, magnesium silicide, or magnesium stannide. These materials generally have a melting point below about 1000.degree. C. and form on the base crystals the size of fingernails or greater. The primary substrate has an epitaxial relationship with a subsequently applied layer of material, and because of this epitaxial relationship, the material deposited on the primary substrate will have essentially the same crystal size as the crystals in the primary substrate.

Abstract: Apparatus is described for use with a solar concentrator such as a parabolic dish (12, FIG. 2) which concentrates sunlight onto the small opening (18) of a solar receiver (16), for protecting the receiver in the event of a system failure that could cause concentrated sunlight to damage the receiver. The protective apparatus includes a structure which can be moved from a stowed position (30) where it does not block sunlight, to a deployed position (30A) wherein it forms a tube which substantially completely surrounds an axis (26) connecting the receiver opening to the center of the concentrator at locations between the receiver and the concentrator.

Abstract: A lead screw positioner (10) is described, which has extremely low noise, including a nut (12) lying about a lead screw (14) and means for flowing gas under pressure between the nut and screw to keep them slightly spaced. The nut forms a plenum chamber (34) which receives pressured air, and has several holes (32) leading from the chamber to the clearance space (20) between the nut and screw to apply pressured air thereto. The nut and screw are devoid of direct sealing contact, so the pressured gas flows from the holes and axially along the screw to the end of the nut, where the gas flows into the environment.

Abstract: Disclosed is a method and apparatus for an optogalvanic spectroscopy system. Orthogonal geometry exists between the axis of a laser probe beam and the axis of a discharge created by a pair of spaced-apart and longitudinally aligned high voltage electrodes. The electrodes are movable to permit adjustment of the location of a point in the discharge which is to be irradiated by a laser beam crossing the discharge region. The cell dimensions are selected so that the cross-section of the discharge region is substantially comparable in size to the cross-section of the laser beam passing orthogonally through the discharge region.

Abstract: A bed (76, 202) of oil shale particles (10) are pyrolyzed in a retort (70, 200) by means of a heated carrier gas stream passing through a central conduit (54, 202) within the bed (76, 202) and then upwardly through a fixed bed (76) or fluidized bed (202) of the shale. The shale is subjected to pyrolysis and evolves kerogen liquid, thermally and pyrolyzed liquids and gases which enter the carrier gas to form a pyrolysis gas. The liquid pyrolysis oil is separated from the pyrolysis gas ion separator (94, 224) and a portion of the separated gas is recycled to a solar heat exchanger (50, 204) and heated to a temperature of at least 350.degree. C. before being fed to the central conduit (54, 202).

Abstract: A GPS receiver having a number of channels, one for each of a plurality of satellites, receives an aggregate of pseudorange code time division modulated signals from some or all satellites and converts the aggregate to baseband and then to digital form for separate processing in the separate channels, each of which includes a complex mixer for adjustment of the baseband signal to a smooth estimate of frequency, .omega., for the next measurement interval, and an N-lag cross correlator which receives a replica of the pseudorange code adjusted for a smoothed estimate of the pseudorange (delay), .tau.. A fast Fourier transform processor computes the signal energy as a function of Doppler frequency for each correlation lag, and a range and frequency estimator computes estimates of pseudorange, .tau., and frequency, .omega..

Abstract: A flow through catalytic reactor (10) which selectively catalytically decomposes methanol into a soot-free hydrogen-rich product gas utilizing engine exhaust at temperatures of 200.degree. to 650.degree. C. to provide the heat for vaporizing and decomposing the methanol. The reactor (10) is combined with either a spark ignited (28) or compression ignited (54) internal combustion engine or a gas turbine (202) to provide a combustion engine system. The system may be fueled entirely by the hydrogen-rich gas produced in the methanol decomposition reactor or the system may be operated on mixed fuels for transient power gain and for cold start of the engine system. The reactor (10) includes a decomposition zone formed by a plurality of elongated cylinders (12) which contain a body (114) of vapor-permeable, methanol decomposition catalyst preferably a shift catalyst such as copper-zinc. A vaporizer (14) is provided for vaporizing liquid methanol prior to introduction into the elongated cylinders (12).

Abstract: A joint (10) is described for connecting a pair of beams to pivot them between positions in alignment or beside one another, which is of light weight and which operates in a controlled manner. The joint includes a pair of fittings (16, 18), and at least one center link (20) having opposite ends pivotally connected to opposite fittings and having axes (36, 38) that pass through centerplanes (36, 38) of the fittings. A control link (24) having opposite ends pivotally connected to the different fittings controls their relative orientations, and a toggle assembly (26) holds the fittings in the deployed configuration wherein they are aligned. The fittings have stops (28, 30) that lie on one side of the centerplane opposite the toggle assembly.

Abstract: A mechanical actuator can be constructed by employing a plurality of memory metal actuator elements in parallel to control the amount of actuating force. In order to facilitate direct control by digital control signals provided by a computer or the like, the actuating elements may vary in stiffness according to a binary relationship. The cooling or reset time of the actuator elements can be reduced by employing Peltier junction cooling assemblies in the actuator.

Abstract: Amorphous metals are produced by forming a molten droplet (115) of metal from source (126) and deploying the droplet into a focused acoustical levitating field or by dropping the unit through spheroidizing zone (116) slow quenching zone (118) and fast quenching zone (120) in which the droplet is rapidly cooled by in the standing acoustic wave field produced between half-cylindrical acoustic driver (168) and focal reflector (166) or curved driver (38) and reflector (50). The cooling rate can be further augmented by first cryogenic liquid collar (160) and second cryogenic liquid jacket (170) surrounding the drop tower (112). The sphere (117) is quenched to an amorphous solid which can survive impact in the unit collector (124) or is retrieved by vacuum chuck (20).