Abstract: A laser comprises an optical resonant cavity construction utilizing opposing corner cube and W-fold mirrors to provide a four-pass folded optical path which is not dependent upon critical alignment between the said mirrors and therefore eliminates necessity for rigid optical bench structure therebetween.

Abstract: An electron beam window structure for broad area electron beam generators wherein a stream of electrons generated in an evacuated enclosure and extending over a broad area are passed through a thin window to a region of high pressure outside the enclosure. The structure is positioned between the metal window and the electron emission means of the electron beam generator and comprises a generally flat metal plate of high thermal conductance having closely spaced parallel slots extending over and covering the intended area of the electron beam. The bottom of each slot is disposed adjacent one surface of the plate and over its length and is provided with a row of closely spaced holes of the same diameter as the bottom width of the slot. The holes go through the remaining material leaving a small web between adjacent holes. The metal window is mounted on the slotted side of the plate while the side of the plate with the holes faces the emission means disposed in the evacuated enclosure.

Abstract: A solenoid operated drive system or actuating unit for driving blood pumps such as intra-arterial "balloon" pumps, implantable pulsatile pumps, external pumps and the like, wherein a shaft attached to the movable end of a bellows is caused to move back and forth by a pair of oppositely disposed solenoids. The extent of the excursion of the shaft and hence the movable end of the bellows is variably controlled by a first stopper fixedly attached to the frame and a second stopper fixedly attached to a carriage which is adjustably carried within the frame. The solenoids are alternately actuated and/or controlled by suitable control signals which are keyed to the heartbeat or R wave. At the beginning of each cycle for each solenoid and for a short time thereafter, depending on the cycle, a voltage is applied to provide maximum drive.

Abstract: Properties of a surface layer of a metal part are modified by changing its composition and microstructure using focused radiant energy. Minor components of an alloy having the metal of the substrate as the major component thereof are applied to the surface and a limited depth surface layer of the substrate metal is melted, the coated-on components are mixed therewith and the mixture is rapidly cooled to produce a desired surfacing alloy to a controlled depth within the substrate and having a fine grained microstructure compared to the microstructure of the substrate metal. The amount of coated-on minor alloy components and the preselected depth of melting of the substrate metal provide alloy composition control.

Abstract: In a laser, a gaseous mixture is suitably heated to a first temperature and at a first pressure to provide a large energy content. The gaseous mixture comprises a polyatomic gas such as carbon dioxide having an upper level, ground state, and intermediate level. It also comprises at least one auxiliary gas such as nitrogen, having an energy level substantially resonant with one of the above-mentioned levels and a relaxation time operative to increase the ratio of the relaxation time of the upper level to that of the lower level. A chamber receives the mixture via a supersonic nozzle proportioned to provide a flow time short compared to the relaxation time of the upper level and long compared to the relaxation time of the lower level and the gas is throttled to a relative low second gas temperature and pressure, whereby population inversion exists in the chamber. An optical resonator defines a light path beam through the gaseous medium in the chamber.

Abstract: A method and apparatus for controlling the power of a laser beam issuing from a gaseous working medium in a working region wherein the gas is subjected to an electric field and an ionizing beam is directed to the gas, ionizing the gas and producing therein secondary electrons sufficient to support laser action wherein the power of the laser beam is controlled by controlling the power of the electron beam and the electron beam power is controlled by an electrical feedback signal from a radiation detector that detects a fraction of the laser beam reflected from a plurality of reflective small wires carried by a rotatable hub which causes the wires to sequentially pass through the laser beam and reflect a small fraction of the laser beam towards the radiation detector.

Abstract: In a method and apparatus for producing and controlling a beam of radiation such as a laser beam issuing from a gaseous working medium in a working region wherein the gas is subjected to an electric field and an ionizing beam is directed to the gas, ionizing the gas and producing therein secondary electrons sufficient to support laser action, the power of the laser radiation is controlled by controlling the power of the electron beam and the electron beam power is controlled by an electrical feedback signal from a radiation detector that detects a fraction of the laser radiation.

Abstract: A cardiac output monitor. The monitor receives signals representing radial arterial pressure, balloon pressure, balloon drive and balloon volume from an intra-aortic balloon pumping system. These signals are processed to define balloon depletion pressure (P.sub.1), ventricle ejection pressure (P.sub.2), balloon volume (BV) and heart rate (HR). The monitor displays the cardiac output according toCardiac output = (P.sub.2 /P.sub.1) (BV) (HR)the monitor also indicates certain improper pumping system operations and can provide a continuous display.

Abstract: A two chamber electrically pumped electron beam stabilized gas discharge laser is enabled to operate at lower electron accelerating voltages for given power applications through provision of very thin separating diaphragms. The apparatus is controlled throughout initial pump down, laser gas filling, laser operation and air release phases to prevent occurrence of a diaphragm rupturing pressure differential between the two chambers or the inadvertent malsequencing of chamber evacuation and backfill.

Abstract: A method of producing a lasable gaseous mixture for use in and operation of electron beam-sustainer carbon dioxide lasers comprising burning a hydrocarbon fuel to produce substantially oxygen free products of combustion, removing undesirable constituents to leave a gaseous mixture which can support laser oscillation comprising substantially only carbon dioxide, nitrogen and hydrogen, collecting the resulting gaseous mixture, and thereafter supply and use it as the active medium in an electron beam-sustainer laser.

Abstract: Working gas for an electron beam discharge laser is generated by an airbreathing, hydrocarbon fuel burning, turbocompressor engine and shaft power of the engine may be utilized to drive a generator to provide electric power to the laser or to drive a compressor to put the turbocompressor exhaust gases in compressed storage for later use in the laser, either mode affording savings in weight and cost of operating materials and/or specific energy conversion efficiency compared to prior art, electric, chemical and gas dynamic laser systems.

Abstract: A metal layer is clad to a metal substrate by laying spaced rods or wires of a cladding metal on the substrate surface and scanning the cladding metal with a continuously operating laser beam, part of which impinges directly on the cladding metal to melt it and part of which impinges on the adjacent surface area of the substrate to improve flow of molten metal thereon. The cladding metal may be fed to the substrate surface in synchronism with laser beam scanning. The process produces a clad layer of the cladding metal on the substrate characterized by a fine and homogeneous structure within the clad on layer and further characterized by uniform and high hardness compared to prior art cladding methods. The surface of the clad may be smoothed by locally oscillating the laser beam during the course of cladding and/or by multiple passes.

Abstract: A laser mirror resistant to thermal distortions produced by radiative heating and/or heating by other processes associated with high power CW lasers. A plurality of rods connect a flexible face portion to a stiff base portion to define an "elastic" arrangement which permits free lateral expansion but resists if not prevents distortion in the form of bending of the face portion. The face portion may be formed1. from a block of heat conductive material which has been deeply slotted from its rear end to define an effectively thin face portion attached to a middle portion of high heat capacity, or2. from a thin plate of heat conductive material cooled from the rear face by either forced convection to, or by nucleate boiling of, a flowing heat transfer media in the middle portion.

Abstract: An MHD generator includes external electrical connectors between adjacent discrete electrodes in one wall of the generator duct, which has opposed electrodes which may lie in a plane at an angle to the direction of gas flow. The electrical connection includes a circuit which adjusts the voltage between the connected adjacent electrodes to insure that the Hall voltage differential between the discrete electrodes which are adjacent to each other in the same wall of the duct does not exceed the damaging breakdown voltage. Indicator means when coupled to the circuits in accordance with the invention comprise diagnostic means which provide a graphic representation of voltage distribution along the length of the generator duct.

Abstract: An MHD generator includes external electrical connectors between pairs of the discrete electrodes in opposite walls of the generator duct, which may lie in a plane at an angle to the direction of gas flow. The electrical connection includes a passive or an active circuit which controls current flow between the connected electrodes to insure that uniform current flow along the length of the duct and that excessive current flow through such discrete electrodes in opposite walls of the duct do not exceed a damaging limit which may otherwise occur. Indicator means when coupled to the circuits in accordance with the invention comprise diagnostic means which provide a graphic representation of current distribution along the length of the generator duct.