Abstract: An apparatus includes a substrate; a group III-Nitride barrier layer; a source electrically coupled to the group III-Nitride barrier layer; a gate on the group III-Nitride barrier layer; a drain electrically coupled to the group III-Nitride barrier layer; a p-region being arranged at or below the group III-Nitride barrier layer; and a recovery enhancement circuit configured to reduce an impact of an overload received by the gate. Additionally, at least a portion of the p-region is arranged vertically below at least one of the following: the source, the gate, an area between the gate and the drain.

Abstract: A method for precision cleaning of a workpiece with a cleaning fluid comprising liquid and/or supercritical fluid carbon dioxide and a primary solvent which is liquid at ambient temperatures and pressures comprises first placing the workpiece in a pressurizable vessel with a removable lid and within an inner tank open at the top; supplying the primary solvent to the inner tank; flushing the primary solvent through the pressure vessel; draining the inner tank to remove the primary solvent; and then supplying liquid and/or supercritical fluid carbon dioxide to the pressure vessel and flushing it through the vessel by withdrawing it from near the bottom of the inner tank.

Abstract: A method for precision cleaning of a workpiece with a cleaning fluid comprising liquid and/or supercritical fluid carbon dioxide and a primary solvent which is liquid at ambient temperatures and pressures comprises first placing the workpiece in a pressurizable vessel with a removable lid and within an inner tank open at the top; supplying the primary solvent to the inner tank; flushing the primary solvent through the pressure vessel; draining the inner tank to remove the primary solvent; and then supplying liquid and/or supercritical fluid carbon dioxide to the pressure vessel and flushing it through the vessel by withdrawing it from near the bottom of the inner tank.

Abstract: An improved precision cleaning method includes introducing a solvent to a cleaning vessel, placing a workpiece in the cleaning vessel and contacting the workpiece with the solvent during a residence period. The cleaning vessel is then pressurized to a target pressure by adding carbon dioxide to the vessel, and additional carbon dioxide is pumped into the vessel while maintaining the target pressure to flush contents of the vessel. Cleaning may be enhanced by pressurizing to above the supercritical point of the carbon dioxide, and cleaning is further enhanced by application of sonic energy or mechanical agitation.

Abstract: An apparatus for gas pressure bonding, hot isostatic pressing or the like in which a workpiece may be treated at elevated temperatures and pressures comprises an elongate cylindrical pressure vessel for enclosing a furnace. The furnace comprises an insulated bottom and an insulated hood with openings near the top and bottom. The insulating hood rests upon the bottom for enclosing a workspace. Means for heating the workspace and means for cooling the pressure vessel are provided. The improvements according to this disclosure are means for establishing a first circulating flow of pressurized fluid down along the interior of the pressure vessel wall, means for establishing a second circulating flow of pressurized fluid down through the workspace.

Abstract: A high pressure gas/oil separator comprising a pressure vessel with a magnetically driven hollow shaft extending thereinto. The shaft has a slinger at its lower end within the vessel. The upper end of the shaft is in communication with a source of the gas/oil mixture. The vessel has a purified gas outlet above the slinger. Gas/oil mixture is thrown by centrifugal force against walls of the vessel and the oil coalesces on the walls and drains to the bottom of the vessel. The purified gas escapes from the vessel through the outlet port.

Abstract: An apparatus or system for cooling the interior of an autoclave furnace vessel after it has been pressurized with a gas and heated. The system comprises a heat conducting conduit opening at one end to the furnace interior and at the other end to a shut-off valve exterior to the vessel. Intermediate the two ends of the conduit is a coil portion comprising a heat exchanger positioned at a location in the furnace where hot vessel gases may be forced through or past the coil. Furnace gases are forced into the conduit and therefore through the coiled portion where they are heated prior to being exhausted. According to a preferred embodiment of this invention, there is a Joule-Thomson valve before the coiled portion of the conduit to reduce the temperature of the exhausting gases prior to arriving at the coiled portion.

Abstract: Apparatus for treating a workpiece at elevated temperatures both under vacuum and under superatmospheric pressures to provide for vacuum sintering and hot isostatic pressing in the same apparatus. The apparatus according to this invention comprises a vacuum-pressure vessel and a furnace within the vessel having a pedestal upon which the hearth rests extending up into the furnace. A first electrical heating means spaced about the pedestal is entirely below the hearth. At least one second electrical heating means is spaced about the workspace above the hearth. Means for separately controlling the first and second electrical heating elements are provided. The furnace can provide substantial uniform temperature distribution to the workpiece resting upon the hearth when the vessel is evacuated by direct radiation from the electrical heating means above the hearth. When the vessel is pressurized, uniform temperature distribution is maintained by convection from the electrical heating means below the hearth.

Abstract: A pressure vessel comprising a cylindrical stress liner, a pair of end plates, a plurality of annular shrink rings positioned about the circumference of the stress liner, and a plurality of coolant-filled annular cooling coils positioned about the shrink rings is disclosed. Nonuniform stress producing bending stresses in the shrink rings are eliminated by the method comprising the steps for detecting a stress concentration in a shrink ring and causing coolant to be recirculated from a reservoir through the coil about the shrink ring.

Abstract: This invention relates to an electric furnace and, in particular, an electric furnace having graphite rod heating elements electrically connected into more than one series circuit. In this way, the heating elements can be arranged to provide individually controllable heating zones.The heating elements are supported by hollow graphite cylinders and flanges extending radially inward from the hollow cylinders. The rod heating elements extend upwardly from the flanges being held near the lower ends thereof.

Abstract: An apparatus or system for cooling the interior of an autoclave furnace vessel after it has been pressurized with a gas and heated. The system comprises a heat conducting conduit opening at one end to the furnace interior and at the other end to a shut-off valve exterior to the vessel. Intermediate the two ends of the conduit is a coil portion comprising a heat exchanger positioned at a location in the furnace where hot vessel gases may be forced through or past the coil. Furnace gases are forced into the conduit and therefore through the coiled portion where they are heated prior to being exhausted. According to a preferred embodiment of this invention, there is a Joule-Thomson valve before the coiled portion of the conduit to reduce the temperature of the exhausting gases prior to arriving at the coiled portion.

Abstract: An apparatus for treating a workpiece at elevated temperatures and pressures comprising an elongate cylindrical pressure vessel. Within the pressure vessel a hearth sits upon a pedestal. Heating elements are circumferentially spaced about the hearth. A heat insulating hood separates the workpiece from the pressure vessel. A cylindrical reflecting shield separates the heating element from the insulating hood.

Abstract: An apparatus for treating a workpiece at elevated temperatures and pressures comprising an elongate cylindrical pressure vessel. Within the pressure vessel a hearth sits upon a pedestal. Surrounding the pedestal and the workspace immediately thereabove is an insulated furnace enclosure. A cavity near the base of the pedestal defines an impeller chamber. An impeller is positioned in the chamber and has a downwardly extending drive shaft. The impeller circulates the pressurized atmosphere. A remotely actuated gate directs the circulating atmosphere to either circulate totally within the furnace enclosure or partially within the furnace enclosure and partially along the interior wall of the pressure vessel.

Abstract: A hanging reaction frame assembly for moving a reaction frame to and from a pressure vessel. The reaction frame is hung from a carriage that moves on tracks spanning a well. The pressure vessel is supported by a scaffold within the well and has a platform that passes through the reaction frame.

Abstract: An apparatus for treating a workpiece at elevated temperatures and pressures comprising an elongate cylindrical pressure vessel. Within the pressure vessel a hearth sits upon a pedestal. A cavity near the base of the pedestal defines an impeller chamber. An impeller is positioned in the chamber and has a downwardly extending drive shaft which is magnetically driven from outside the pressure vessel.

Abstract: This invention relates to an electric furnace and, in particular an electric furnace having graphite rod heating elements electrically connected into more than one series circuit. In this way, the heating elements can be arranged to provide individually controllable heating zones.

Abstract: A work piece in a hot gas isostatic bonding furnace is cooled by increasing convection within the furnace prior to depressurizing. The convection may be wholly due to thermal gradients or may be supplemented by a compressor. The cooling jacket for the furnace walls may supply the entire cooling or may be supplemental heat exchanger. The quenching takes place within the furnace without changing the atmosphere.

Abstract: A gas pressure bonding furnace having a convection shield with (1) monolithic tubular refractory insulation having its upper end surrounding the work receiving hot zone of the furnace and its lower end depending to a cool zone, (2) an impervious tubular metal shell surrounding the tubular insulation and holding it under compression by differential thermal expansion, (3) a cover closing the top of the shell by a gas tight gasket seal and (4) a piston actuated by the gas working pressure to hold the cover closed. In a preferred form, the insulation is cast in the shell and the composition is an alumina cement with embedded alumina balloons.