Abstract: A pulse damper for use in a liquid chromatographic solvent delivery system includes a cavity within a housing containing a compliant medium. The compliant medium being an elastomer. As a consequence, a solvent flow volume can be precisely formed and maintained.

Abstract: The present invention is directed to a solvent pressurization system for use in liquid chromatography which includes a source of pressurized gas, a plurality of sealed vessels that are adapted to hold solvents therein, each of the vessels having a gas input port, said vessels being located within a closable compartment; a double manifold having a distribution chamber in communication with the pressurized gas from the gas source and an exhaust chamber communicatable with a venting system, a set of fittings for each vessel for controlling the gas flow from the distribution chamber to the vessel and from the vessel to the exhaust chamber, each set of fittings including inlet valve means and outlet valve means and an element for opening or closing both valve means together.

Abstract: A system for assuring a more even powder flow rate in a flame spray gun. A powder metering device entrains powder into a gas. The gas with entrained powder is coupled to the flame spray gun. Vibration means, coupled to the powder and gas conduit, is provided to prevent any powder from settling in the conduit.

Abstract: The present invention is directed to an improved test wafer for testing the overlay alignment of a second level pattern over a first level pattern for testing lithographic equipment used in making microcircuits, which includes four conductors with circuitry provided for each conductor measuring the conductance thereof, the conductors being constructed and arranged so that the conductance of the first conductor relative to the second conductor, and the conductance of the third conductor relative to the fourth conductor is indicative of the offset of said first level pattern with respect to said second level pattern.

Abstract: An apparatus for positioning a thermogravimetric furnace includes a furnace mounting bracket which is rotatable about and linearly translatable along a single axis. In addition, simultaneous rotational and linearly movement of the furnace is excluded.

Abstract: A lamella-shaped sample carrier is attached to a tubular carriage and is movable into a graphite tube of a graphite tube cuvette from the end fact below the measuring light beam of an atomic absorption spectrophotometer. The carriage with the sample carrier is movable between an inner position, a dosing position and an outer position. The sample carrier is electrically heated in any position by means of busses. Drying and ashing of the sample take place outside the graphite tube. The graphite tube is then heated to atomizing temperature, while the sample carrier is in its outer position. Subsequently, the sample carrier is advanced into the inner position and heated itself. Thus, rapid atomization of the sample is achieved.

Abstract: A liquid level sensor includes a sensor coil co-axially positioned within a heater coil. Preferably, the sensor is coiled on a core of thin-walled stainless steel tubing to minimize the thermal conductivity along the axis thereof. The probe provides a continuous measurement of the level of a liquid due to the difference in thermal conductivity between the vapor and the liquid within the reservoir.

Abstract: In a photometer for measuring atomic fluorescence, a partial light beam is branched off the exciting light beam by means of a mirror having a hole. The partial light beam falls on a scattering disc, from which a reference light beam impinges upon the detector through opposite windows of the measuring cell. A chopper alternately transmits the exciting light beam and the partial light beam. The signal thus obtained at the detector permits compensation of the influence of variations of the light source brightness and of contamination of the windows.

Abstract: A sample vessel for carrying a sample and storing same in a high vacuum. The vessel includes a hollow body which is open at one end. A specimen carrier plate is coupled by a translating mechanism so that it can slide in and out of said hollow body through the opening. An O-ring seal is provided to seal the carrier plate to the vessel thereby sealing the specimen carried thereby inside the hollow body which can then be evacuated leaving a high vacuum inside.

Abstract: A memory checking circuit for periodically reading the data from all locations therein. The circuit includes logic to correct and restore data from locations where an error has occurred. The circuit quickly identifies all memory locations present during search mode at a fast rate and reads all present locations at a slower rate during normal mode.

Abstract: A differential scanning calorimeter includes a baseline correction apparatus which simultaneously corrects for both linear and curvilinear heat flow variation between the sample and reference holders.

Abstract: Apparatus for use in conducting both static and dynamic thermomechanical analysis includes a load member, one end of which is supported by the sample located in a sample receptacle, eventually in a selected gas atmosphere, in heat equilibrium and the other end of which is loaded statically by a weight or dynamically by the armature of an electromagnet.

Abstract: A plasma flame spray gun suitable for being constructed physically smaller than comparable power prior art plasma flame spray guns. The gun includes a nozzle having a tapering portion on the inlet side thereof. A cathode with a flat tip is positioned to at least partially extend into the tapering portion of the nozzle. A gas distribution ring is located around the cathode for creating a vortex around the cathode tip. This causes the arc formed between the tip and the nozzle to have a root which spins around the perimeter of the nozzle tip resulting in less wear and, therefore, extended part life.

Abstract: An achromatic beam splitter which is mechanically and thermally stable includes a first aperture, which aperture is overfilled, and an achromatic optical element. The aperture and element are preferably positioned in an optical plane having uniform illumination.

Abstract: A needle assembly for feeding a carrier gas into a sample vessel during the head-space analysis of a sample includes a lateral outlet passage for conveying the gas.

Abstract: A plurality of samples subject to the same thermostatting time periods are directed one by one to the inlet section of a gas chromatograph for analysis in accordance with the head space method. To this end, a first heatable sample store adapted to be stepwise advanced is provided, in which thermostatting of the samples is accomplished. A second sample store also adapted to be stepwise advanced is provided, from which sample vessels are transferred one by one into the first sample store.

Abstract: An apparatus useful in identifying a solute includes a microbore separation column having unusually large particle packing making up the bed thereof. In addition, the microbore column is excessively long compared to conventional columns. Preferably, the column is thermally stabilized.

Abstract: This invention relates to overlay test measurement systems which are useful for testing lithographic instruments used in making microcircuits, which includes a single second-level pattern set in the middle of a checkerboard-like arrangement of first level patterns alternating with opaque patterns, the patterns being constructed and arranged so that if a second substantially identical cluster is imaged on the first cluster with the second level pattern of the second cluster aligned with any one of the first level patterns on the first cluster then the opaque patterns of the second cluster would be aligned with the other first level patterns on the first cluster thereby protecting them from exposure.According to a feature of the invention there is provided a method of making a test wafer of the type described as well as a method of testing the alignment of lithographic tools using the aforesaid test mask and test wafer.

Abstract: This invention relates to apparatus for effecting alignment and spacing control of a mask and wafer for use, for example, in x-ray lithography, which includes, in combination, two optical channels for effecting lateral and vertical alignment at two spaced alignment targets respectively on the element, two spaced position sensors located on a line which is oblique with respect to a line joining the two alignment targets, and linkage for maintaining the distances between the position sensors and the element equal one to the other.

Abstract: An improvement in the operation of a system where the driving means is a stepper motor comprises provision of a special software routine implemented by a microprocessor controlling the delivery of a counted series of pulses to drive the stepper motor. The improved routine removes excitation from the stepper motor when not receiving a series of stepping pulses thus eliminating the heat dissipation of such a motor when not in motion. Loss of position is avoided by utilizing the inherent detenting action of the stepper motor's permanent magnet field. Provision is also made for proper damping to prevent error due to overshoot. Where several stepper motors are used in a system the reduction of heat dissipation permits a significant simplification of the system cooling requirements. A single power supply may be shared among the motors thus further simplifying the system.