Abstract: The present invention resides in a dual fueled burner gun providing reduced production of oxides of nitrogen. The gun operates in a gaseous fueled mode when it is charged with a gaseous fuel or in a liquid fueled mode when it is charged with a liquid fuel. The gun may also operate in a gaseous/liquid fueled mode in which it is charged with both the gaseous and liquid fuels.

Abstract: A successive approximation analog-to-digital converter controllable by signals to start and interrupt conversion asynchronously with respect to clock signals used to regulate operation of the converter. Separate control signal processing circuits register the occurrence of start-convert and conversion-interrupt signals supplied by a user of the converter, and generate corresponding control signals synchronized with the clock signals. Asynchronous operation of the converter allows it to function in a short-cycling mode, wherein the number of bits of resolution in the conversion process is automatically reduced as little as possible to complete each conversion in the time allotted by the user. A continuous-conversion signal is also provided, to permit operation on a continuous basis, without providing periodic start-convert signals.

Abstract: An improved sequential threshold detection circuit for use in the receiver of a spread-spectrum communication system is disclosed wherein the improvement resides in the employment of a feedback circuit for maintaining a pre-selected constant median dismissal time. In the preferred embodiment the feedback circuit comprises a flip-flop (70), a very long time constant integrator (72), and a one-shot (74) connected between a comparator (64) and a summing amplifier (60) for varying a threshold bias voltage applied to the summing amplifier. In an alternative embodiment, the feedback circuit serves to selectively vary the gain of a variable gain amplifier (110) in such a manner to vary the individual trial and error dismissal times to provide a substantially constant median dismissal time over the entire detection process.

Abstract: An active semiconductor device, such as a Gunn effect device, capable of operation at extremely high frequencies, fabricated in situ on a substrate that also serves as a dielectric waveguide to propagate energy from the device. In the embodiment disclosed, a Gunn effect diode is formed on a substrate of gallium arsenide (GaAs), together with a cavity region and a metalized heat sink layer permitting operation at relatively high power levels. A bias current is applied through a conductive strip and then through the cavity region to the diode, and a quarter-wave choke is provided in the conductive strip to prevent transmission of radio-frequency energy back along the strip.

Abstract: A high-speed sample-and-hold circuit well suited for fabrication in monolithic form, the circuit including a pair of capacitors used to track a differential analog signal, and at least two switches for connecting the analog signal to the capacitors in a tracking mode, and for isolating the capacitors from the analog signal in a hold mode. In a preferred embodiment of the invention, the switches are diodes and each capacitor is driven differentially through a separate pair of diodes, which are forward-biased in the tracking mode and reverse-biased in the hold mode. Additional circuitry is provided to compensate for variations in characteristics of the diodes due to temperature changes. Furthermore, the effects of capacitive coupling through the diodes in the hold mode are minimized by disconnecting the analog input signal and substituting a signal derived from the held signal stored in the capacitors.

Abstract: In-situ retorting methods include forming an in-situ mass of rubblized, hydrocarbon-containing minerals covering at least part of that mass with a nonflammable liquid such as water, uncovering part of the mass and retorting to produce hydrocarbon values from that part, and then progressively or sequentially uncovering other parts of the mass and retorting hydrocarbons from those parts. Methods for forming highly permeable rubblized masses include forming a retorting zone in a kerogen-bearing formation wherein two walls of the retorting zone form a low angle to one another, and cleaving oil shale from the upper wall beginning near the intersection of the two walls and proceeding upwardly.

Abstract: Sulfided carbonaceous materials suitable for reinforcing such diene rubbers as styrene-butadiene rubber and natural rubber include carbon, sulfided iron dispersed in, intimately associated with and at least partially bonded to the carbon, and hydrogen.

Abstract: A frequency-tracking feedback circuit for acquiring a communication carrier signal from a relatively noisy environment. The circuit includes a digital phase-frequency detector, a limiter, a mixer, and a voltage-controlled oscillator, connected in a long control loop in such a manner that an input band of signals is translated in frequency until the desired carrier is centered within a relatively narrow acquisition window. The characteristics of the loop are such that acquisition may be achieved even when the total power of the noise in the input signal band exceeds the carrier power, provided that the noise is relatively uniformly distributed over the input band. A technique is also disclosed for compensating from any unbalance in the noise spectrum, so that relatively low carrier-to-noise ratios can be tolerated.

Abstract: Acoustic wave devices employing shallow bulk acoustic waves rather than surface acoustic waves, to provide higher frequencies of operation and other significant advantages, such as less susceptibility to aging and less sensitivity to surface contamination. In each embodiment of the invention, a transmitting transducer and a receiving transducer are oriented on the surface of an anisotropic piezoelectric crystal to achieve substantial coupling of shallow bulk acoustic waves and essentially zero coupling of surface acoustic waves. In one embodiment of the invention, various types of grating filters utilize shallow bulk acoustic waves, and a set of parallel mechanical or electrical discontinuities at or near the surface of the crystal provide reflection of acoustic energy at a frequency determined by the spacing of the discontinuities. Uniformly spaced gratings provide bandpass filter operation, and gratings with graduated spacings provide for frequency compression or expansion.

Abstract: A solar array having solar cells mounted on a substrate and electrically joined by rear connector elements on the substrate and front connector elements secured between the cells to the substrate is fabricated by placing the array components in assembled relation and utilizing induction heating to heat to their fusion temperatures a thermoplastic adhesive layer on the substrate and contacting fusible cladding on the solar cells and the connector elements while retaining the components in firm contact to effect adhesive bonding of the solar cells and front connector elements to the substrate and metallic bonding of the solar cells and connector elements to one another.

Abstract: Digital circuitry, and a corresponding method for its operation, for detecting frequency or phase-angle differences between two digital input signals. The detector includes a differentiating circuit to provide signals indicative of the times of occurrence of a selected feature of the input signals, such as a pulse edge, and a pair of memory devices, such as flip-flops, which can be set by respective input signals. The detector further includes a feedback circuit operative to clear both flip-flops in the event that the input signals would be effective to place both of them in a set condition. The feedback circuit operates in a parallel, rather than a series timing relationship with input circuitry that sets the flip-flops, and the performance of the detector is thereby significantly improved, as evidenced by a smaller dead zone in its phase output characteristic for a given frequency of operation, or a capability of operation at higher frequencies for a given degree of degradation.

Abstract: An electrothermal thruster operating at high temperature is employed for satellite control.

Abstract: A mixture of at least two particulate metals capable of undergoing an exothermic reaction to form an intermetallic compound is provided to sustain decomposition of borane reactants to yield hydrogen or deuterium.

Abstract: A two cycle internal combustion engine with improved cylinder scavenging. The described engine embodiment is a baffled piston two cycle internal combustion engine whose power is substantially increased by directing fuel mixture in the normally spent gas filled region behind the piston baffle during each intake-exhaust portion of the engine cycles to scavenge spent gas from this region and increase the total volume of fuel mixture in the cylinder at the time of ignition. According to the preferred practice of the invention a portion of the fuel mixture displaced from the engine crankcase to the cylinder intake port or ports is diverted to auxiliary ports in the cylinder wall which direct the mixture against the rear side of the piston baffle to effect through scavenging of the region directly behind the baffle.

Abstract: Energy trapping elements for use with shallow bulk acoustic wave devices of various kinds, to minimize the insertion loses in such devices due to spreading of electroacoustic energy into the crystal substrate upon which the devices are constructed. Electroacoustic energy propagated in a substrate is trapped close to the surface of the substrate by means of trapping elements comprising a plurality of strips or grooves disposed on the surface of the substrate in the path of the propagated energy, and oriented approximately perpendicularly to the direction of propagation. The spacing of the elements is such that their stop-band frequency, at which energy will be reflected, is substantially different from the characteristic center frequency of the entire device, in order that the elements will serve a purely trapping function and not a reflecting function.

Abstract: A prepolymer is comprised of the reaction product of at least one aliphatic bismaleimide, at least one aromatic amine and at least one aromatic bismaleimide in combination with an aromatic and/or a cycloaliphatic epoxy resin providing at least two functional epoxy groups to provide a low temperature curable composition. The cured products are strongly adherent to a variety of substrates.

Abstract: A low distortion phase compensated wideband amplifier system includes a low cost, power efficient Class C amplifier positioned along a primary signal path and a feedback loop coupled to provide negative feedback of distortion signal components in the amplified output signal. The negative feedback significantly reduces noise components including intermodulation noise while variable delay phase compensation permits a greater signal to noise ratio over a broader band of frequencies at the system output.

Abstract: The negative precharge of a sealed nickel-cadmium battery cell is reduced and the uncharged negative capacity is correspondingly increased to increase the overcharge protection of the cell by overdischarging the cell at a relatively high rate and reacting hydrogen evolved in the cell during such overdischarge with a hydrogen getter which forms a hydride with the hydrogen to prevent excessive hydrogen pressure buildup in the cell.

Abstract: Arsenic or other dopant selected from Group III or Group V of the Periodic Table of Elements is diffused into a silicon substrate to form a semiconductor product having a buried region, such as a buried layer or channel, by providing the substrate with a layer of polycrystalline silicon doped with the selected dopant and heating the substrate and layer in an oxygen environment at a temperature and for a period of time sufficient to oxidize all or substantially all the polycrystalline silicon and simultaneously diffuse the dopant into the substrate. The substrate comprises single crystal silicon or other silicon form whose oxidation rate is comparable to or less than the polycrystalline silicon to permit complete oxidation of the polycrystalline silicon without excessive oxidation of the substrate.

Abstract: A prepolymer comprised of the reaction product of at least one aliphatic bismaleimide, at least one aromatic amine and at least one aromatic bismaleimide is combined with at least one cycloaliphatic epoxy resin having a melting point less than about 120.degree. F. and at least two functional epoxy groups to provide a low temperature curable composition. The cured products are strongly adherent to a variety of substrates.