Abstract: By using two SAR antennas spaced a known distance, B, and oriented at substantially the same look angle to illuminate the same target area, pixel data from the two antennas may be compared in phase to determine a difference .DELTA..phi. from which a slant angle .theta. is determined for each pixel point from an equation .DELTA..phi.=(2.pi.B/.lambda.)sin(.theta.-.alpha.), where .lambda. is the radar wavelength and .alpha. is the roll angle of the aircraft. The height, h, of each pixel point from the aircraft is determined from the equation h=R cos .theta., and from the known altitude, a, of the aircraft above sea level, the altitude (elevation), a', of each point is determined from the difference a-h. This elevation data may be displayed with the SAR image by, for example, quantizing the elevation at increments of 100 feet starting at sea level, and color coding pixels of the same quantized elevation.

Abstract: Systems are described for the acoustic levitation of objects, which enable the use of a sealed rigid chamber to avoid contamination of the levitated object. The apparatus includes a housing forming a substantially closed chamber, and means for vibrating the entire housing at a frequency that produces an acoustic standing wave pattern within the chamber.

Abstract: Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500.degree. C. to 1500.degree. C. by adding to it small amounts of calcium, barium, or strontium. This novel compound is an excellent thermoelectric material.

Abstract: Sugars are converted to a mixture of solvents including butanol by a fermentation process employing a coculture of microorganisms of the Clostridium genus, one of said microorganisms favoring the production of butyric acid and the other of which converts the butyric acid so produced to butanol. The use of a coculture substantially increases the yield of butanol over that obtained using a culture employing only one microorganism.

Abstract: A system is described for loading newly mined material such as coal, into a shuttle car, at a location near the mine face where there is only a limited height available for a loading system. The system includes a storage bin (18) having several telescoping bin sections (20-23), and a shuttle car (14) having a bottom wall (64) that can move under the bin. With the bin in an extended position and filled with coal (FIG. 3), the bin sections can be telescoped (FIG. 4) to allow the coal to drop out of the bin sections and into the shuttle car, to quickly load the car. The bin sections can then be extended, so they can be slowly filled with more coal while awaiting another shuttle car.

Abstract: Instrumentation for sensing moisture content of material using a transient thermal pulse is comprised of a sensing probe (12) having a sensing element (14) in the form of a ribbon excited by a constant current pulse from a source (16) to increase the temperature, and therefore the resistance, of the ribbon linearly. Moisture in web material (10) will limit the increase of temperature during the pulse in proportion to the moisture content. This increase in temperature produces a proportional increase in resistivity which is measured with a Wheatstone bridge (R.sub.1, R.sub.2, R.sub.3, 14) as a change in voltage displayed by a measurement display unit (20). The probe (12) is glued in a shallow groove of a Lucite bar (15c) and connected to copper pins (15a, 15b) embedded in the bar. A cylindrical Lucite block (21) may be used to hold the sensing element (14) connected to axial pins (22a, 22b) in order for the probe to roll and thus reduce its wear.

Abstract: A system is described for measuring the distance to an object by comparing a first component (18) of a light pulse that is reflected off the object (14), with a second component (20) of the light pulse that passes along a reference path (26) of known length, which provides great accuracy with a relatively simple and rugged design. The reference path (26) can be changed in precise steps so that is has an equivalent length approximately equal to the path length of the light pulse component that is reflected from the object. The resulting small difference in path lengths can be precisely determined by directing the light pulse components into opposite ends of a detector (70) formed of a material that emits a second harmonic light output at the locations where the opposite-going pulses pass simultaneously across one another.

Abstract: A photovoltaic cell, such as a solar cell, is provided which has a higher output voltage than prior cells. The improved cell includes a substrate of doped silicon, a first layer of silicon disposed on the substrate and having opposite doping, and a second layer of silicon carbide disposed on the first layer. The silicon carbide preferably has the same type of doping as the first layer.

Abstract: A method is described which uses acoustic energy to separate particles of different sizes, densities, or the like. The method includes applying acoustic energy resonant to a chamber (14) containing a liquid or gaseous medium to set up a standing wave pattern that includes a force potential well wherein particles within the well are urged towards the center, or position of minimum force potential. A group of particles to be separated is placed in the chamber, while a non-acoustic force such as gravity is applied, so that the particles (50-52 in FIG.2) separate with the larger or denser particles moving away from the center of the well to a position near its edge and progressively smaller lighter particles moving progressively closer to the center of the well. Particles are removed from different positions within the well, so that particles are separated according to the positions they occupy in the well.

Abstract: State of the art Fourier transform spectrometers are useful scientific tools. But, they are very complex precision electro-optical-mechanical instruments. To simplify the instrument, the need for a mechanical slide mechanism to create a path difference has been eliminated by the use of retro-reflecting mirrors (16, 18) in a monolithic interferometer assembly (11) wherein the mirrors (16, 18) are not at 90 degrees to the propagation vector (29, 43) of the radiation (27), but rather at a small angle (49). The resulting interference fringes (51, 53) create a double-sided interferogram (33) of the source irradiance distribution which is detected by a charge-coupled device (CCD) array (23). The position of each CCD pixel (25) in the array is an indication of the path difference between the two retro-reflecting mirrors (16, 18) in the monolithic optical structure. The Fourier transform of the signals generated by the CCD array (23) provide the spectral irradiance distribution of the source.

Abstract: Systems are described for coupling a pair of optical fibers to pass light between them, which enables a coupler to be easily made, and with simple equipment, while closely controlling the characteristics of the coupler. One method includes mounting a pair of optical fibers (12A, 14A) on a block (26) having a large hole (28) therein, so the fibers extend across the hole while lying adjacent and parallel to one another. The fibers are immersed in an etchant (40) to reduce the thickness of cladding (20) around the fiber core (18). The fibers are joined together by applying a liquid polymer (16, FIG. 6) so the polymer-air interface moves along the length of the fibers to bring the fibers together in a zipper-like manner, and to progressively lay a thin coating of the polymer on the fibers.

Abstract: Disclosed is a method of coating a substrate with an amorphous metal comprising the step of bombarding a solid piece of the metal with ions of an inert gas in the presence of a magnetic field to provide a vapor of the metal which is deposited on the substrate at a sufficiently low gas pressure so that there is formed on the substrate a thin, uniformly thick, essentially pinhole-free film of the metal.

Abstract: An unsaturated polyester, such as propylene glycol-maleic acid-phthalic acid prepolymer dissolved in styrene is interpolymerized with an ultraviolet absorber of the formula: ##STR1## and/or an antioxidant of the formula ##STR2## where R and R.sup.2 are selected from H or lower alkyl such as methyl and R.sup.1 is tertiary alkyl such as tertiary butyl to form a polymer stable to exposure to the outdoors without degradation by ultraviolet radiation, thermal and/or photooxidation.

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: An electrostatic levitation system is described, which can closely control the position of objects of appreciable size. A plurality of electrodes surround the desired position of an electrostatically charged object, the position of the object is monitored, and the voltages applied to the electrodes are varied to hold the object at a desired position. In one system, the object is suspended above a plate-like electrode (16, FIG. 1) which has a concave upper face (26) to urge the object toward the vertical axis (20) of the curved plate. An upper electrode (18) that is also curved can be positioned above the object, to assure curvature of the field at any height above the lower plate. In another system, four spherical electrodes (81-84, FIG. 6) are positioned at the points of a tetrahedron, and the voltages applied to the electrodes are varied in accordance with the object position as detected by two sensors (94,96 FIG. 4).

Abstract: An acoustic levitation system is provided for acoustically levitating an object, by applying a single frequency from a transducer into a resonant chamber surrounding the object. The chamber includes a stabilizer location (29, FIG. 2) along its height, where the side walls of the chammber are angled so they converge in an upward direction. When an acoustic standing wave pattern is applied between the top and bottom of the chamber, a levitation surface (28) within the stabilizer does not lie on a horizontal plane, but instead is curved with a lowermost portion (31) near the vertical axis of the chamber. As a result, an acoustically levitated object (30) is urged by gravity towards the lowermost location (31) on the levitation surface, so the object is kept away from the side walls of the chamber.

Abstract: Two collocated, weakly coupled probes, on loop and one dipole, detect the magnetic and electric fields inside a maser cavity. Signals from the probes are compared in phase, and the signal output from the phase detector is applied to a varactor, the reactance of which is coupled into the cavity by a microwave coupler. Alternatively, the varactor may be placed inside the cavity. Any deviation of phase from 90.degree. as detected by the phase detector will then produce an error signal that will change the reactance coupled into the resonant cavity to change its reactance, and thus correct its resonance frequency. An alternative to using two probes is to use a single disk probe oriented to detect both the magnetic and electric fields, and thus provide the error signal directly.

Abstract: Disclosed is a method and apparatus for growing in a gravitational field a microscopic crystal from a solution. Solution is held in a vertical chamber which is relatively thin, the thin dimension being generally perpendicular to the vertical. There is a substrate crystal disposed at either the upper or lower end of the chamber and the crystal grows from this substrate crystal in one direction. In accordance with this invention, the temperature conditions of the solution are controlled so that as the crystal forms the effects of buoyant convection within the solution are minimized. This is accomplished in two different ways depending upon whether the crystal is grown from the upper or lower end of the chamber. When grown from the upper end of the chamber, the temperature of the solution is controlled so that it remains essentially isothermal so that there is essentially no heat loss from the solution.

Abstract: An electrical testing structure and method whereby a test structure is fabricated on, e.g., a large scale integrated circuit wafer along with the circuit components and has a van der Pauw cross resistor in conjunction with a bridge resistor and a split bridge resistor, the latter having two channels each a line width wide, corresponding to the line width of the wafer circuit components, and with the two channels separated by a space equal to the line spacing of the wafer circuit components. The testing structure has associated voltage and current contact pads arranged in a two by four array for conveniently passing currents through the test structure and measuring voltages at appropriate points to calculate the sheet resistance, line width, line spacing, and line pitch of the circuit components on the wafer electrically.

Abstract: A method for driving a two-phase turbine 10 characterized by an output shaft 20 having at least one stage including a bladed rotor connected in driving relation with the shaft, and wherein a two-phase fluid is introduced into said one stage at a known flow velocity and caused to pass through the rotor for imparting angular velocity thereto, the speed of the rotor being controlled so that the angular velocity of the tips of the blades thereof is a velocity equal to at least 50% of the velocity of the flow of the two-phase fluid.