Abstract: A switchable local oscillator for use in a shared mixer radiometer is capable of providing at least two separate frequencies. The local oscillator contains at least two cavity resonators, a voltage controlled oscillator controlling a microwave generator, a microprocessor to intermittently control the voltage controlled oscillator and an output voltage detection circuit to provide output voltage levels to the microprocessor. The microprocessor controls the voltage controlled oscillator to tune the microwave generator through a frequency range. Output voltage level of the local oscillator is detected, and a resonant frequency is determined. In response, the microprocessor fixes the voltage of the voltage controlled oscillator at a voltage corresponding to the resonant frequency of one of the cavity resonators. Microprocessor control of the voltage controlled oscillator is then relinquished. The local oscillator generates a resonant frequency while measurements are made by the radiometer.

Abstract: A method and apparatus for accurately generating a digitally synthesized sinusoidal voltage is started by storing digital values for sine waveforms in a read only memory. A first and second digital to analog converters are connected to the read only memory through latches. The outputs of the first and second digital to analog converters are alternatively switched between the inverting input and the non-inverting input of an operational amplifier such that one of the first and second digital to analog converter is connected to the inverting input while the other is connected to the non-inverting input. The output of the operational amplifier is connected to the inverting input through a variable capacitance, the feedback being determined by the one of the first and second digital to analog converter connected to the inverting input. A clock is used to control the connection of the first and second digital to analog converter to the inverting input and to control the determination of the feedback.

Abstract: A low resistivity contact to a high-Tc superconductor is made by forming a contact pad on the surface of an abraded or freshly prepared superconductor by depositing an inert metal on the surface so that a surface resistivity between the surface of the high-Tc superconductor and the pad is established of less than about 1000.mu..OMEGA.-cm.sup.2 at high-Tc superconductor operating temperatures.

Abstract: A hydraulic system has a rotary valve which controls multiple hydraulic dces such as double-acting piston type actuators and which prevents deactivated devices from creeping. The valve has an outer housing and a rotatable inner member which form high pressure inlet, low pressure outlet, and control stages. The control stages utilize partial commutators (part circumferential grooves) and ports on the valve member selectively to couple control ports of the housing respectively to the inlet stage or the outlet stage by rotating the inner valve member (the control ports being connected to the hydraulic devices). At the inlet and outlet stages, the valve member has full annular commutators which communicate continuously with a high pressure inlet port and a low pressure vent port of the housing as the valve member is rotated. The valve member also has internal passageways which connect each control stage partial commutator and fluid port to either the inlet commutator or the outlet commutator.

Abstract: A quad disk static pressure probe apparatus (10) including: a hollow stem member (15) having a plurality of static pressure ports (16) disposed on its periphery; an apertured collar unit (14) surrounding the stem member (15) and being in open fluid communication with the static pressure ports (16); and, inner (21) and outer (18) pairs of disk members operatively secured to the stem member (15) above and below the location of the static pressure ports (16).

Abstract: An electrodeposition process and a bath therefore are disclosed for performing the electrodeposition of hard smooth coatings of trivalent chromium. The electrodeposition process is accomplished energy efficiently. The bath includes chromium chloride as a source of chromium, citric acid to complex the chromium, and a wetting agent which is preferably Triton x-100. Preferably, bromide is also provided in the solution to maintain the hexavalent chromium production at the anode at a low level. Ammonium chloride is also preferably provided to improve the conductivity and also the current distribution in the bath. Boric acid is provided to advance the reaction kinetics. The pH of the bath is maintained at approximately 4.0 and the temperature is maintained at approximately 35.degree. C. Either a direct current or pulsed current is used for the deposition process. Hard smooth coatings of trivalent chromium are deposited through use of the process and the bath of the claimed invention.

Abstract: A recirculating oven molecular beam source of unitary construction compri a shaped porous wicking oven substrate nearly saturated with the working material and having a cavity with source and collimating regions formed therein.

Abstract: A method for producing quasi-crystalline films by direct vapor deposition through sputtering is provided. The method is applicable to all alloys which can be converted to quasi-crystalline structure by melt spinning.

Abstract: Photosensitive anthracene compounds containing two anthracene rings joined by a flexible linkage, and containing a functional group as an annular substituent on one of the anthracene rings, react with polymers to form materials useful in information proceedings.

Abstract: The present invention is a fibrous monolithic ceramic product of high deny and a process for making the product. The product has a microstructure of coated fibers with planes of weakness between a core of each coated fiber and its respective coat or between each coated fiber and adjacent coated fibers, thereby toughening the product. The planes of weakness are sufficiently weak to deflect a crack from normal to the plane of weakness to a direction parallel to the plane of weakness. The green body from which the product is formed, can be plastically deformed at room temperature, formed in near-net-shape, and densified by pressureless sintering.

Abstract: Toughening agents are produced by the application of high pressure, sufficient to transform a powder material into a denser high pressure polymorph. When the pressure is released, the high pressure phase is retrieved metastably at ambient conditions of pressure and temperature. The amount of high pressure phase retained at ambient conditions depends on the relative hydrostaticity of the pressurized environment and particle size of the powder. The high pressure phase is almost completely retained in a hydrostatic environment. One embodiment of the process of the present invention produces pressure transformation toughened zirconia comprising a high pressure phase having a symmetry no greater than tetragonal (defined as tetragonal II) dispersed within a matrix of a less dense monoclinic phase.

Abstract: A method for determining a subsurface property value gradient of a body includes the step of generating a Rayleigh wave in the body by passing a current through a first meander coil having predetermined spaced wires determining a wavelength of the generated Rayleigh wave. A second meander coil identical to the first meander coil is spaced at a predetermined distance from the first meander coil. The Rayleigh wave is then detected with the second meander coil and the velocity of the Rayleigh wave is determined. A property value of the body is determined at a depth determined by the wavelength of the Rayleigh wave which property value is a function of the determined velocity. The above steps are then repeated with at least one other pair of first and second meander coils having different predetermined spaced wires such that at least one second property value at a second depth is determined and a subsurface property value gradient is produced.

Abstract: A linear recirculating roller bearing is disclosed where the rollers travel n an inclined groove where the non-loading rolling groove is parallel to the loading roller groove. In the preferred embodiment four sets of rollers are provided which are able to bear loads from any direction. The angle of the rollers with respect to the bearing is dependent on the materials used and the overall dimensions of the system so that the bearing gap expands, due to temperature changes, at the same rate as the rollers.

Abstract: A double-handed, robot end effector or gripper which can be used for moving nd positioning machine parts. The gripper is elongate and symmetric about its longitudinal axis, having a first and a second set of hands extending in each of the two transverse directions. Each hand has a removable finger and is positioned about an accurately repeatable midpoint. The hands are mounted on and are moved about the longitudinal plane by a ball screw which is rotated by either an electric motor or an air driven motor through gears located at one end.

Abstract: Apparatus and method for monitoring transactions on a high speed interface us and for selectively storing information about such transactions together with the time of such transaction and the state of the automaton. The apparatus comprises two parallel memories for respectively storing a regular table and a default table, and a memory selector for choosing between the table data of the two memories. A bus trap stores data information obtained from the bus and compares the stored information with a stored data template. A transition detector receives control signals from the bus and generates clock signals used by other system elements upon the detection of a transition. A hash coder utilizes a hash key together with state information to generate an address for entering the regular table memory. A state latch stores an address provided by the memory selector for the default table.

Abstract: A system and method are disclosed for acoustic scintillation liquid flow measurement. Measurement is carried out by acoustic beams transmitted perpendicular to the direction the component of liquid flow to be measured, with both phase and amplitude measurements being made to enable generation of accurate speed of flow indications which are indicative of liquid flow through a broad area being monitored as opposed to a single point therein. In one realization of this invention, a pair of projectors are mounted on one side of the flow area, such as a channel to be monitored, and a pair of receivers are mounted on the other side of the flow area with pulsed acoustic signals from each of the projectors being transmitted in separate parallel paths through the liquid, such as water, to the receivers.

Abstract: A tracking system for measuring at least the spatial coordinates of a target and possibly the angular orientation of the target. A collimated beam is directed to the target and a mirror attached to the target reflects this beam back to a tracking point. Photosensors attached to the tracking or target point provide error signals to a servo system which controls optics at the tracking or target points to provide the direction necessary to accomplish the coincidence of the beams. An interferometer interferes the source beam with the beam that has travelled twice between the tracking and target points in order to measure the separation. By measuring the directions of the beams relative to structure attached to the tracking and target points, the target point can be located in spatial coordinates and additionally the orientation of the target structure can be determined.

Abstract: Disclosed is an improved specimen cell for maintaining a scanning electron microscope specimen under nearly physiological conditions during observation when said specimen includes liquids having a relatively high vapor pressure. A cavity in the specimen cell mounts an open or closed specimen module which is scanned by the electron beam through a small aperture. During preparation of the electron microscope for observation, the aperture is closed by a door so as to prevent evaporation of liquids from the specimen. The door is mechanically or electronically opened to facilitate observation thus minimizing the exposure of the specimen to the desiccation and/or destructive vacuum effects. Furthermore, the aperture is sized so as to provide a resistance to vapor flow through the aperture while permitting bidirectional electron flow facilitating the electron microscopic observation of the specimen.

Abstract: Fish oil is purified by extraction with supercritical carbon dioxide.

Abstract: A wide dynamic range, wide bandwidth, analog-to-digital conversion system and method. A plurality of overlapped analog-to-digital converters are utilized in conjunction with scaling amplifiers to provide a plurality of output ranges. Means for selecting the set of output bits which provides a magnitude representation of the input signal are provided along with means for outputting a digital representation of the appropriate range.