Abstract: A uniform and thin layer of a semiconductor is grown on a semiconductor substrate by an improved liquid phase epitaxy growth method. The growth solution is supercooled and is pushed rapidly over the substrate on which the layer of solute is grown. In GaAs the amount of supercooling is typically 3.degree. to 5.degree. C. and a constant thickness ultra-thin layer (about 0.18 microns) is grown on top of a GaAs substrate.

Abstract: A process for making a new type of diffuser is described wherein an electric field is applied to a liquid containing a suspension of transparent platelets having a refractive index higher than that of the fluid and a different dielectric constant. The field causes the planes of the platelets to be aligned substantially parallel to that of the field but to have random angular orientation with respect to the direction of the field. While the platelets are thus aligned, the liquid is hardened to permanently retain the platelets in the aligned position even in the absence of the electric field. The resulting structure produces good diffusion of light with a high ratio of transmitted to reflected light.

Abstract: A hanging bollard has a pivotally attached hanger which is capable of supporting a load by a line coupling device. A preferred form of the coupling device is spring loaded to allow detachment of the bollard cable from the load only when the coupler and load are supported by the hanger. The hanger is pivoted out of the coupler engaging position when the bollard is to be used as a conventional bollard.

Abstract: A source of electrons or charged particles is contained in a baffled enclosure at less than atmospheric pressure. The source projects the electrons or charged particles to strike a target with a velocity which generates soft x-rays. The target is in a chamber at substantially atmospheric pressure in a gaseous environment which is only slightly dispersive and absorptive of the soft x-rays. Access to this chamber is provided to insert a mask and substrate for lithographing by the soft x-rays.

Abstract: This invention relates to a method and apparatus for isotope separation and in particular to separating the desired isotope from the gas in which it is contained by irradiating it with a laser and thereby selectively providing kinetic energy to the isotope through inelastic events, monomolecular or bimolecular, in order to cause it to segregate within or fly out of the gas stream in which it is contained.

Abstract: A torque controlled brake of the disc type has a caliper which is free to rotate about the axis of the wheel shaft. The caliper contains a rotatably mounted lever having disc pads which press upon the disc to provide the frictional braking force. The pads close onto the disc in response to rotational motion of the lever with respect to the caliper. This rotational motion is produced by a manually controlled brake lever on the handlebar of a bicycle. The rotational motion is restrained by a cable attached to the bicycle frame and to the lever, thus providing a negative feedback effect. The braking torque is dominated by the restraining force which bears a fixed ratio to the force applied by the manual brake lever. A limited manual braking force thereby determines the maximum braking torque.

Abstract: Thick, finely-grained films of cermets are fabricated using conventional techniques of sputtering the ceramic and the metal onto a substrate. The cermet is then subjected to differential sputtering in which the metal is sputtered away faster than the ceramic to leave a ceramic-rich surface layer having excellent secondary-electron-emission properties for low-energy incident electrons. Typical of such cermets are MgO/Au, MgO/Pt and MgO/Ag. The presence of metallic particles in the bulk of the films and the small size of the ceramic particles greatly reduce surface charging while allowing the emitter film to be made thick enough to have a long operating life under adverse device conditions.

Abstract: A bed of graphite particles is placed beneath a nuclear reactor core outside the pressure vessel but within the containment building to catch the core debris in the event of failure of the emergency core cooling system. Spray cooling of the debris and graphite particles together with draining and flooding of coolant fluid of the graphite bed is provided to prevent debris slump-through to the bottom of the bed.

Abstract: Liquid mixtures are used as the active medium in two-photon resonant four-wave mixing processes to achieve efficient nonlinear conversion of infrared laser frequencies. The resonant energy levels involved in these four-wave mixing processes are Raman-active vibrational modes of a molecular species which is one of the major constituents of the liquid mixture. Additional molecular and/or atomic constituents are added to the active molecular species to adjust the dispersion of the medium to optimize the nonlinear process. Diluents further may be used to fine-tune the two-photon resonance parameters to better match available infrared laser sources.

Abstract: A composite panel is described in which the face sheets and the core have properties such that the panel produces a double wall resonance near the low frequency end of the principal speech bands and in which the panel produces interaction between the symmetric and antisymmetric mode in the principal speech bands, thereby providing greater than mass-law transmission loss over a substantial portion of the audio frequency spectrum. At frequencies above the principal speech bands effects are determined primarily by the properties of the individual face sheets.

Abstract: High-temperature (1200-1500K) electrolysis of water and recombination of the products in a medium-temperature (530K) fuel cell achieve a practical efficiency exceeding 50%. A solid electrolyte is chosen for the electrolytic cell and in combination with the Bacon fuel cell, which offers high efficiency and automatic replenishing of water vapor into the cycle realizes a high-efficiency electrochemical cycle. Both high-temperature, gas-cooled reactors and conventional combustion processes may be used as heat sources. Unconventional heat sources, such as concentrated solar energy, can also be used. A regenerative counterflow heat exchanger and a waste-heat power plant serve as energy-conserving devices. An important feature of this cycle is the flexibility of operation that can be achieved by adding hydrogen storage. Switching among power-generating, load-averaging, and hydrogen-generating modes can then be done by simple gas-flow valves.

Abstract: A continuously programmable matched filter device using a piezoelectric substrate capable of propagating acoustic wave signals on a selected surface thereof and a semiconductor substrate mounted adjacent and spaced from such surface. Means are provided for altering the conductivity pattern in the semiconductor substrate in accordance with the wave form of a reference wave signal so that a representation of the reference wave is effectively stored therein. Storage of the reference is achieved with electrostatic charge by supplying a plurality of electrons in the spatial region between the substrates or by manipulating the carriers in the semiconductor material into trapping states in order to produce such altered conductivity pattern. A second signal can thereupon be propagated along the piezoelectric substrate to interact with the stored reference conductivity pattern to provide either correlation or convolution operation depending on the direction of propagation thereof along the piezoelectric surface.

Abstract: An electric guitar is described which provides signals from each of its electrically conducting strings by the cutting of magnetic field lines. The magnetic fields are produced by removably mounted permanent magnets which produce concentrated fields. The return wire or wires of the strings are near the surface of the neck. Various circuit configurations are used to minimize noise pickup, to combine the signals from each signal and to modify the sound produced by each string.

Abstract: According to the method and apparatus of this invention, water is kept away from the arc in underwater arc welding by means of material contained in a water-tight enclosure. The water-tight enclosure is formed by pressing the seal at the bottom of the enclosure against the object to be welded and by closing the opening for the electrode on top of the enclosure by using the fluid nature of a viscous polymer. Gas generated in the enclosure during welding is expelled through check valves located along two longitudinal sides of the enclosure.The enclosure is prepared above the water surface and then delivered to the welding site. No inert gas is needed.

Abstract: An asynchronous logic array capable of directly implementing Petri net specification of digital systems is disclosed. The array can be used in general synthesis of asynchronous digital circuits and systems. The parallel nature of the array gives the realized systems the speed and other characteristics of hard wired circuits even though they are realized from a uniform logic array. The logic array is particularly suited for implementing control circuits and promises to extend the field of microprogramming to asynchronous and parallel computers.

Abstract: A transistor structure capable of high frequency operation with low collector currents is obtained by fabricating the transistor using nitride techniques to minimize the emitter area and base width area beyond that obtainable by conventional masking techniques. The emitter is surrounded on three sides by low capacitance dielectric which reduces its emitter-to-collector capacitance and hence improves high frequency performance.

Abstract: Appropriate heating and temperature sensing means are immersed in a medium the thermal conductivity, k, and thermal diffusivity, .alpha., of which are to be determined both in the presence of and in the absence of a flow of fluid therethrough. The method and system used for making such measurements operate in accordance with a thermal model of the heating means and the medium wherein the heating means is treated as a distributed thermal mass and wherein heat conduction occurs in a coupled thermal system which comprises both the heating means and the adjacent region of the medium which surrounds such heating means.

Abstract: A multilayer membrane, which is useful as synthetic skin, is disclosed herein. A first layer is formed from a material which does not provoke an immune response and which is also insoluble and nondegradable in the presence of body fluids and/or body enzymes. Preferred materials for the first layer are crosslinked composites of collagen and a mucopolysaccharide. A second layer is formed from a nontoxic material which controls the moisture flux of the overall membrane to about 0.1 to 1 mg./cm.sup.2 /hr. Suitable materials for the second layer include synthetic polymers such as silicone resins, polyacrylate or polymethacrylate esters or their copolymers, and polyurethanes.

Abstract: A continuously programmable matched filter device using a piezoelectric substrate capable of propagating acoustic wave signals on a selected surface thereof and a semiconductor substrate mounted adjacent and spaced from such surface. Means are provided for altering the conductivity pattern in the semiconductor substrate in accordance with the wave form of a reference wave signal so that a representation of the reference wave is effectively stored therein. Storage of the reference is achieved with electrostatic charge by supplying a plurality of electrons in the spatial region between the substrates or by manipulating the carriers in the semiconductor material into trapping states in order to produce such altered conductivity pattern. A second signal can thereupon be propagated along the piezoelectric substrate to interact with the stored reference conductivity pattern to provide either correlation or convolution operation depending on the direction of propagation thereof along the piezoelectric surface.

Abstract: Tunneling electronic devices responsive to infrared and far infrared radiation are formed by overlapping deposits which define ultra-thin dielectric layers (less than aout 10 Angstrom thickness) between metal layers, and contact areas of the order of 1 micron.sup.2 or less. Preferred embodiments feature operation in the negative impedance region, particularly using multibarrier structures or operating at low temperature with both metals superconductors, and incorporation of the same in oscillators and multivibrators. Other embodiments feature two or more such devices in the form of triodes having positive feedback achieved by radiative or inductive coupling using integrally deposited line structures as the respective antennas or inductors. Similar deposited antennas, e.g. dipole antennas, are employed to produce radiative outputs from the devices achieving, e.g. tunable sources of radiation in the far infrared or infrared.