Abstract: A second harmonic, optical generator is disclosed in which a laser diode produces an output pumping beam which is focused by means of a graded, refractive index rod lens into a rod of lasant material, such as Nd:YAG, disposed within an optical resonator to pump the lasant material and to excite the optical resonator at a fundamental wavelength. A non-linear electro-optic material such as MgO:LiNbO.sub.3 is coupled to the excited, fundamental mode of the optical resonator to produce a non-linear interaction with the fundamental wavelength producing a harmonic. In one embodiment, the gain medium and the non-linear material are disposed within an optical resonator defined by a pair of reflectors, one of which is formed on a face of the gain medium and the second of which is formed on a face of the non-linear medium. In another embodiment, the non-linear, electro-optic material is doped with the lasant ion such that the gain medium and the non-linear doubling material are co-extensive in volume.

Abstract: A memory tester for testing a matrix of memory elements, such matrix having spare rows and columns of memory elements to be used for repair of the memory under test. The memory tester tests the memory matrix to derive failure data and stores the failure data in corresponding rows and columns in a second memory matrix. Failure data in the second memory is scanned, in a first pass, row-by-row and during the first pass scan when the number of failures in any row exceeds the number of spare columns that row is flagged for replacement. Next, in a second pass, the columns of failure data are scanned column-by-column and during the second pass when the number of failures in any column exceeds the number of spare rows, that column is flagged for replacement. If, during either of the first or second pass, the number of flagged rows or columns, respectively, exceeds a certain number, such as the spare rows or columns, that pass is interrupted and the analysis jumps to the next pass.

Abstract: Miniature thermal fluid flow sensors of the airfoil type are made in batch form by forming the thermal fluid flow sensors on a thin sheet of material and bonding the sheet over an array of duct structures and dicing the individual sensors and duct structures apart. In one thermal flow sensor configuration, a flow heater is dispsoed inbetween first and second thermal flow sensors in heat exchanging relation therewith. A third thermal flow sensor is disposed upstream of the others out of heat exchanging relation with the heater for operation of the heater at a certain temperature above that sensed by the third sensor. In the low flow regime, flow is measured by the difference between the outputs of the first and second sensors, whereas in the high flow regime, the power required to maintain the temperature of the heater serves as a measure of the flow.

Abstract: A diode pumped Nd:YAG laser is disclosed. The YAG rod is coated on its ends to define an optical resonator containing the YAG rod. The YAG rod is made sufficiently short, i.e., 1 mm, so that it will support only two axial resonant (lasing) modes. The rod is transversely stressed to polarize the two original modes and to excite a third lasing mode orthogonally polarized to the first two modes. The third mode is separated from the first two modes to provide stable, single mode TEM.sub.001 output. The transverse stress is applied by means of a spring clamp made of a material, Be-Cu, having a low temperature coefficient.

Abstract: A batch method for fabricating semiconductive capacitive force transducers is disclosed wherein a first wafer of silicon or fused silica is recessed by etching to define a array of force transducer structures, each including a deflectable portion supported from a surrounding frame portion. The first wafer is thermoelectrically bonded between a pair of glass or quartz plates, each plate having an array of electrode structures for capacitively sensing deflection of the individual force transducers. Each electrode structure includes a lead portion passing over the frame portio of the transducers and being spaced from the frame to provide a gas communication passageway through the frame to the capacitive gap between the electrode structure and the deflectable portion of each transducer. The composite assembled wafers are notched along cleave lines generally outlining the individual transducer structures.

Abstract: A monolithic phasematched harmonic generator is obtained by optically pumping an optically nonlinear lasant member having reflective faces defining the monolithic optical resonator. Phasematching is achieved, in one case, by inclining a totally internally reflective face of the resonator at a proper angle relative to other faces of the resonator to angularly separate and resonate lasant waves of the proper polarization. In a second case, a clad fiber resonator of optically nonlinear lasant material has its cladding arranged to guide and thus resonate only lasant waves of the correct polarization. In a third case, the optical nonlinear coefficient of the optically nonlinear lasant material is spatially modulated with a period equal to an odd integer number of coherence lengths, of the harmonic generation process, to obtain quasi-phasematched operation. Phasematched operation improves the efficiency of the harmonic generation process.

Abstract: A selected component of a fluid mixture, for example a reduced sulfur compound vapor in air, is detected by selectively adsorbing the component onto a conductive thin layer of material having a chemical affinity for such component and observing the resultant change of electrical resistivity of the layer. The sensitivity of the detector changes with accumulation of the component on the sensor. The accumulation of the component on the sensor is removed by oxidizing and evolving the component from the sensor to restore the sensor to a linear operating region. The accumulated component is preferably oxidized by reacting the component with ozone. The dynamic range of the sensor is increased by counteracting the tendency for the component to accumulate by continuously feeding back ozone to or controlling the temperature of the sensor so that the sensor operates in a linear region near null.

Abstract: In an apparatus for rounding the edges of semiconductive wafers, the wafers are loaded onto two parallel counter rotating screws one having a right hand thread and the other having a left hand thread. The grooves of respective ones of said screw engage the edges of the semiconductive wafer to be rounded. The grooves of the respective screws are of rounded cross-section and an abrasive slurry is introduced into the grooves to facilitate abrading of the edges of the wafers. A pressure roller engages the edges of the wafers and forces the wafers into the grooves to further facilitate rounding of the edges. Due to the action of the screws, the wafers, as they are being rounded are caused to traverse the length of the screws to provide a continuous processing of the wafers.

Abstract: A low NO.sub.x staged combustor for a TEOR steam generator includes a primary combustion chamber lined with an improved refractory lining. The refractory lining includes a first layer of low density ceramic fibrous thermal insulation as of 4" in thickness coated on its hot face with a protective coating of a durable tough material. The ceramic fibers of the insulative layer are oriented normal to the plane of the hot face. In one embodiment, a low density castable refractory thermally insulative layer is sandwiched between the shell of the combustion chamber and the first layer of fibrous insulation. In a second embodiment, a low density thermally insulative ceramic fibrous layer is sandwiched between the shell of the combustion chamber and the first layer of fibrous insulation. In the second embodiment, the ceramic fibrous layers are adhered to the shell by refractory hangers embedded in the fibrous insulation and resistance welded to the shell.

Abstract: A current driver circuit for an inductive load, such as a motor winding, provides unidirectional, controlled current through the winding by use of two pulse width modulator switches on opposite sides of the winding or bidirectional current control by use of two pairs of pulse width modulated switches; each pair straddling the winding relative to the power supply. Each pair of switches is modulated in two different modes to control current during two different operating conditions. The first mode of modulation is used for all but rapidly decaying winding current conditions and a second mode provides control for rapidly decaying winding current. In the first mode, unidirectional current to the winding from the power supply is pulse width modulated while the companion switch of the pair is on.

Abstract: The location method uses relatively low frequency electromagnetic fields, e.g., 1-1000 Hz, for determining the relative position and/or orientation of a transmitting magnetic dipole antenna by using a vector field receiver. The transmitting antenna for subterranean location, is preferably a single axis, elongated solenoid with a ferromagnetic core. The receiving sensor may be a precise three-axis magnetic field detector of either a magnetometer or search coil type. Measurements are made for one or more positions of either the transmitter or receiver, or with one or more transmitters or receivers. The relative location of the transmitter and the receiver is calculated with respect to some known survey station by a method of successive approximations. The operating frequency is chosen to minimize field distortion from common steel structures, such as pipe, casing or railroad tracks, and to minimize field scattering such as from conducting inhomogeneities in the earth.

Abstract: Charged particles (ions or electrons) are directed into a drift tube closed off at the upstream and downstream ends by electrical grid members and having an axial magnetic field therein with a substantial radial component. The grids are pulsed to trap the charged particles in the drift tube where the radial magnetic field component mixes their axial and orbital momenta. The potential of the downstream grid is successively lowered for successively extracting particles having a successively lower energy. This analyzer is particularly useful for analyzing surface constitutents.

Abstract: In a low NO.sub.x power and steam generator for thermally enhanced oil recover, a gas turbine fired with nitrogen-bearing crude oil and air produces power and hot turbine exhaust. A portion of the turbine exhaust is fed into the primary combustion chamber of a two-stage combustor for supplying the combustion air for burning a high nitrogen-containing crude oil in the primary combustion zone under fuel-rich conditions. The combustion is completed in a secondary combustion zone supplied with air derived from a second portion of the turbine exhaust at about 1200.degree. F. A third portion of the turbine exhaust is fed into a convection stage disposed to receive the exhaust from the secondary combustion zone for capturing the heat from the turbine exhaust and from the exhaust of the secondary zone and converting it to steam.

Abstract: A time of flight mass spectrometer includes means for gating the flow of ions from the source to the detector with a modulation function, the frequency of which is swept. The detected ion current is obtained as a function of the ion current modulation frequency to derive an ion mass interferogram output in the frequency domain. The interferogram output is Fourier transformed from the frequency domain to the time domain to obtain a time of flight mass spectrum output in the time domain. The Fourier transform time of flight mass spectrometer provides increased duty cycle and signal-to-noise ratio for a given scan time.

Abstract: A miniature solid state near room temperature laser includes a laser crystal doped with a laser ion and an absorber ion. The absorber ion absorbs pumping radiation derived from the output of a laser diode and transfers the absorbed energy to the laser ion for inverting the population of the desired energy transition levels to produce an eyesafe output beam with wavelengths greater than 1.4 microns. In a preferred embodiment, the host crystal is YAG and it is co-doped with Ho as the laser ion and Er as the absorber ion. A small concentration of Tm ion may be doped into the crystal to enhance pumping efficiency. Improved efficiency can be obtained by cooling the laser crystal with a thermoelectric cooler and by tuning the output of the diode laser pump to an absorption peak of the absorbing ion.

Abstract: An immersion-type thermal fluid flow sensor is disclosed in which the temperature dependent sensing resistor means is carried from a flexible ribbon-shaped septum immersed in the flow and arranged in a spiral, meander or other geometrical configuration to partition the total flow passageway into a plurality of parallel flow portions. In one embodiment, the partitioned flow passageways are dimensioned to have a length to cross-sectional dimension ratio for providing laminar flow conditions over the operating flow range of interest. In another embodiment, a heater is provided for heating the septum to a temperature near that of the sensing resistor to reduce the time constant of the flow measurement. In another embodiment, a thermal loading element is coupled in heat exchanging relation with the sensing resistors for increasing the critical flow rate and thus for increasing the operating range of the flow regime wherein the temperature difference .DELTA.

Abstract: An electron spectroscopy system is disclosed which is specially suited for chemical analysis of electrically isolated specimens. X-rays or other ionizing radiation is focused to a relatively small spot on the surface of the electrically isolated sample to be analyzed. An electron energy analyzer has its input optics focused such that the input field of view of the electron energy analyzer is coincident with the beam spot produced by the focused beam of ionizing radiation on the specimen so as to capture secondary photoelectrons emitted from the surface of the sample under analysis. The energies of the secondary photoelectrons are analyzed to obtain a spectrum of the constituents of the surface of the sample under analysis. A flood beam of relatively low energy electrons is directed onto the surface of the sample for neutralizing the positive surface charge in the region of the beam spot.

Abstract: Wafers are unloaded from a hot wafer processing boat of the type having a plurality of elongated parallel electrodes defining elongated processing gaps therebetween with the wafers being serially spaced apart lengthwise of the gap. A wafer carrier, into which the wafers are to be unloaded from the hot boat, has elongated receiving means, preferably formed by folds of the wafer carrier, extending lengthwise of the elongated electrodes of the boat. The wafer carrier is positioned over the boat and the boat and the carrier are inverted so that the wafers drop from the hot boat into the receiving means of the wafer carrier. In a preferred embodiment, once the wafers have been unloaded onto the folded wafer carrier, the wafer carrier is unfolded to facilitate access to the wafers.

Abstract: Miniature thermal fluid flow sensors of the airfoil type are made in batch form by forming the thermal fluid flow sensors on a thin sheet of material and bonding the sheet over an array of duct structures and dicing the individual sensors and duct structures apart. In another embodiment, thin carrier sheet portions of a wafer bearing the thermal fluid flow sensors of the airfoil or grid type are supported by surrounding frame portions of the wafer. The wafer is diced to separate the individual sensing chips. The respective chips are mounted across respective fluid flow ducts. For the airfoil type sensor, portions of the frame are broken away for undisturbed flow over the thin carrier and sensor. In one thermal flow sensor configuration, a flow heater is disposed in between first and second thermal flow sensors in heat exchanging relation therewith.

Abstract: A thin film of magnetic recording material is sputter deposited over a base layer of gold and tantalum on a polished substrate. A protective layer of gold and tantalum is deposited overlaying the magnetic recording film. A solid lubricant layer such as carbon, preferably in the form of graphite, gold, silver, tin, molybdenum disulfide, and tungsten disulfide is sputter deposited or ion plated over the protective layer to reduce wear. The recording contacting portion of the recording head is similarly coated with a solid lubricant material. Other suitable protective materials include tantalum, niobium, tungsten and nitrides and carbides of such metals. In a preferred method for making such recording members, the layers are successively sputter deposited in an evacuated sputter chamber, whereby the recording layers and protective coatings are formed in a continuous process requiring only one pump down.