Abstract: A plunger seats in the outlet end of a cavity formed in an injector housing. The plunger is moveable within the cavity between seated engagement with the outlet end and a position which permits fluid to flow out the outlet end. The cavity is sealed to withstand pressures on the order of 2000 bar. A groove formed in the wall of the plunger or in the wall of the cavity receives liquid sample from a sample feed line which is formed in the body of the housing and terminates adjacent the groove when the plunger is seated in the outlet end of the cavity. A source of mobile phase fluid is connected to the upper end of the cavity by an inlet line. By external displacement means, the plunger is moved out of seated engagement within said cavity to permit a jet stream of mobile phase fluid to sweep the sample from the sample groove out through the outlet end of the cavity and onto a chromatographic column connected to the injector housing.

Abstract: An unheated septumless on-column injector with two internal flow paths is provided. A syringe means is positioned adjacent and communicates in vapor-tight relationship with the inlet ends of the two internal flow paths. The first internal flow path accepts and guides a needle from said syringe means onto the column of a gas chromatograph to permit injection onto the column. The second internal flow path allows the syringe means to either be loaded from or purged into an attached, sealed container. The needle of the syringe means is movable between the first and second paths by external manipulation. In particular embodiments, carrier gas is provided to sweep the sample into the low diameter column and cooling means is provided to ensure that the point of injection of the liquid onto the chromatographic column is maintained at a temperature below the boiling point of the most volatile component of the liquid sample.

Abstract: An IMPATT oscillator is thermally stabilized for pulsed operation by utilizing the dissipative heat during subperiods of pulsed operation and a variable self-heating due to a bias voltage applied during non-oscillating subperiods. The oscillator comprises an IMPATT diode mounted on a platform which is attached to a housing defining a resonating cavity. The platform has a thermally insulating base with a layer of thermally and electrically conducting material applied thereon. The thickness of the layer of thermally and electrically conducting material must be sufficient to permit microwave resonances to occur within the cavity. The thermal resistance of the layer is selected to permit the junction temperature to remain constant even for the highest ambient temperature condition. Constant junction temperature over a wide range of ambient temperature produces constant power and frequency characteristics.

Abstract: A feed forward AC voltage regulator utilizes a step-up, step-down transformer to apply adjustment voltages to an unregulated AC line. Analog circuitry periodically samples the unregulated AC line input and compares it with a scaled representation of the desired line voltage. Digital circuitry converts the information from the analog sampling and comparison to an instruction command which activates an appropriate solid state switch associated with a tap on a multitap transformer connected to the regulated AC output line. The taps are successively located on the multitap transformer to provide selectable adjustment voltages of various values. The switched-in adjustment voltage is provided the proper polarity and applied to the primary of the step-up, step-down transformer, thereby applying to the secondary the adjustment voltage needed to move the regulated AC output line to the desired level.

Abstract: A processor apparatus is provided in which a blackbody radiator having a constant planar energy flux characteristic is placed in opposition to semiconductor material. The blackbody source produces a constant planar energy flux to uniformly heat the material. The source is heated to a sufficiently high temperature for a sufficient time to anneal or activate a semiconductor wafer or to epitaxially regrow a thin epitaxial film. The processor is operated by accomplishing the steps of presenting a blackbody radiator in opposition to semiconductor material to be thermally treated, radiatively heating the material to a sufficiently high temperature for a sufficient time to accomplish the desired process result, and cooling and removing the material. In the interval between presentation of successive samples of the material to the source, the source may be shuttered or idled to reduce energy consumption.

Abstract: An electron bombardment ion source of the Freeman type incorporates an electrode having multiple segments which are electrically connected in parallel to provide increased surface area for constant cross section.

Abstract: A fluorescent composition useful in thin-layer chromatography comprises an inert porous particle having a fluorescent material fixedly attached by covalent chemical bonding to the surface thereof. A process for synthesizing this fluorescent composition is disclosed. A method for detecting the radioactivity of a radioactive species using a cell packed with such a fluorescent composition is also disclosed.

Abstract: A method for etching a semiconductor wafer on an RF etch table employs a succession of different biases on an extension member positioned adjacent the periphery of the table. The extension member is electrically conductive, but is insulated from the etch table. The extension member is positioned with respect to the periphery of the table in a manner such that the plasma sheath induced above the etch table is continued beyond the periphery of the table, thereby eliminating the focusing of ions on the edges of an item being etched on the table. As different bias voltages are applied to the extension member, different etch profiles are experienced on the semiconductor wafer. The aggregation of etch profiles produces a more uniform overall etch.

Abstract: An RF etch table has a biased extension member positioned adjacent its periphery. The extension member is electrically conductive, but is insulated from other conductive members in the system. The extension member is positioned with respect to the periphery of the table in a manner such that the boundary of the plasma induced above the etch table is continued beyond the periphery of the etch table, thereby eliminating the focusing of ions onto the edges of an item being etched on the table. The potential impressed upon the extension member produces a dark space above its surface having a sufficient height so that the horizontal configuration of the sheath above the etch table is continued beyond its edges. More uniform etching is accomplished.

Abstract: A grooved solar cell for deployment at a set angle with respect to incoming radiation has reduced contact obscuration and series resistance. A regular array of walls formed by grooves in a crystalline semiconductor substrate is exposed to incoming radiation. Metallic contacts are formed on those walls of the grooves which are not to be exposed to sunlight. The solar cell is mounted in an apparatus at a set angle with respect to incoming radiation. The array of walls is exposed to incoming radiation while the walls with metal contacts are substantially shadowed. In a preferred embodiment the grooves are formed by using orientation specific etches.

Abstract: A method for fluorescence enhancement of dansyl derivatives of active hydrogen compounds which are easily separated in a liquid chromatography column using a polar solvent system but whose fluorescence efficiency is diminished in such polar solvents, by changing the environment of the dansyl derivative without changing the solvent.

Abstract: On-column detection by an optical detector is accomplished with a flexible silica column. The flexible fused silica column has an inner diameter less than 500 .mu.m, an external protective coating with a stripped portion near the end of the column. The stripped portion is placed in the working path of an optical detector in order to detect and resolve the sample.

Abstract: A nut assembly for use on an injection switch for a chromatograph has a nut surrounded by a moveable member which is disposed to travel co-linearly with respect to the axis of the nut. The moveable member is biased so that its upper end extends above the nut to engage the body of a sample syringe. Upon engagement with the sample syringe the moveable member moves downwardly against the bias means. The bias means then triggers the microswitch. Upon withdrawal of the needle of the sample syringe the moveable member returns to its original position.

Abstract: The invention is a method for controlling the temperature of a primary heat-generating source in an environment whose temperature may vary widely. A heat-pipe is used to carry the heat from the source to a sink at ambient temperature. A separate control source applies heat to the heat pipe. The condensed liquid returning in the heat pipe is partly evaporated by the control heat, whereby the flow of liquid available for evaporation by the primary heat source is reduced and the heat conducted away from the source by the pipe is consequently reduced. The control source heat is regulated by a servo circuit to maintain the temperature of the primary source. The efficiency is higher than prior-art controllers using a constant thermal impedance between source and sink.

Abstract: A unitary electromagnet having two gaps is provided for the double deflection scanning of a charged particle beam. The unitary electromagnet is configured to permit traverse by said beam through the gaps in a plane defined by the gaps. The depth of the gaps is large as compared to the length to accommodate the scan of the beam. The mode of scanning is determined by the waveform used to energize the windings of the electromagnet and includes axial sweep scanning, off center scanning and split scanning.

Abstract: A method for determining the end point for a physical etching process step measures the current at the target being etched and detects changes in the current. Changes in the current measured at the target are indicative of transitions between dissimilar materials or of depth of penetration in a particular material. Momentary changes in the etching flux of the physical etching process are factored out by measuring the current on a mask placed in the vicinity of the target and by subtracting mask current from current measured at the target.

Abstract: Direct ohmic contact between the cells in an epitaxially grown cascade solar cell is obtained by means of conductive interconnects formed through grooves etched intermittently in the upper cell. The base of the upper cell is directly connected by the conductive interconnects to the emitter of the bottom cell. The conductive interconnects preferably terminate on a ledge formed in the base of the upper cell.

Abstract: An optoelectronic assembly obtains substantially improved coupling efficiency between small core optical fibers and small area detectors and emitters. The assembly includes a housing containing an active optoelectronic device and a light transmissive single crystal semiconductor window. The light transmissive single crystal semiconductor window seals the housing and physically protects the device from the environment. The single crystal semiconductor window has an index of refraction higher than conventional glass windows, preferably greater than 2, in order to reduce beam spreading between the optical fiber and small area detectors or emitters. The window material is preferably single crystal GaP.

Abstract: A weak anion exchange composition useful in polyfunctional compound chromatographic separations comprises an inert porous particle having a tetra-substituted silane material fixedly attached by covalent bonding to the surface thereof. A process for synthesizing the weak anion exchange composition is disclosed together with methods for separation of polyfunctional compounds and their isomers using a column packed with such weak anion exchange composition.

Abstract: Method of operation and apparatus for a salt gradient solar pond employing a novel barge carrying a plurality of two axis stabilized high temperature concentrator solar cell arrays including means to control the flow rate of the concentrator solar cell array cooling fluid to optimize power station characteristics.