Transport of minority-carriers in graded-composition semiconductors and its impact on graded-band-gap base transistors operated at high currents
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Hutchby, J. A.↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Stitch-bond parallel-gap welding for IC circuits
Stitch-bonded flatpacks are superior to soldered dual-in-lines where size, weight, and reliability are important. Results should interest designers of packaging for complex high-reliability electronics, such as that used in security systems, industrial process control, and vehicle electronics.
Chvostal, P.↗
A theoretical study of heterojunction and graded band gap type solar cells
The work performed concentrated on including multisun effects, high temperature effects, and electron irradiation effects into the computer analysis program for heterojunction and graded bandgap solar cells. These objectives were accomplished and the program is now available for such calculations.
Chiang, J. P. C.↗
Eliminating gaps in split rings
Simple installation method allows thinner, lighter tether rings than conventional procedures, saving expensive materials. Installer inverts ring with pliers before it is slid over cable, then returns it to its original position after installation. Ring is in correct orientation, and coils are tightly compressed for high reliability fastening.
Gould, R. W.↗
Panel discussion: Bridging the gap technology developing flight hardware
The development of an engineering data base for aerospace batteries is discussed.
Ford, F. E.↗
Determination of deep level capture cross sections in wide band-gap semiconductors by means of an electron beam
The paper presents a general theory for the determination of the short circuit current generated by a sinusoidally amplitude-modulated electron beam in the presence of recombination centers with an arbitrary number of charge states. It is shown that a measurement of the coherent phase shift with respect to the incident beam as a function of the modulation frequency of the beam ascertains the magnitudes of electron and hole capture cross sections. The surface exposed to the electron beam must have a negligible surface recombination velocity for the measurements to be unambiguous.
Von Roos, O.↗
A Study of Production of Miscibility Gap Alloys with Controlled Structures
Composite materials were directionally solidified using a new technique to align the constituents longitudinally along the length of the specimen. In some instances a tin coating was applied and diffused into the sample to form a high transition temperature superconducting phase. The superconducting properties were measured and compared with the properties obtained for powder composites and re-directionally solidified powder compacts. The samples which were compacted and redirectionally solidified showed the highest transition temperature and wildest transition range. This indicates that both steps, powder compaction and resolidification, determine the final superconducting properties of the material.
Parr, R. A.↗
Low-gravity experiments on Liquid Phase Miscibility Gap (LPMG) alloys: Materials Experiments Assembly (MEA)
Space shuttle experiments which study the massive separation which occurred during sounding rocket Al-In alloy tests are described. The gradient cool experiment studies surface tension driven droplet migration and particle pushing in an LPMG alloy. Isothermal experiments on the Te-Tl alloys test the hypothesis that LPMG systems with low surface energies produce relatively fine, and uniform emulsions and dispersions. It also examines the effect of droplet concentration on phase separation kinetics. Isothermal plunger experiments on Al-In alloys determine whether surface tension driven convection currents originating at a free surface contribute to massive separation. They ascertain whether In-rich droplets migrate under the action of a temperature gradient when they are not influenced by the crucible walls.
Gelles, S. H.↗
Effect of reabsorbed recombination radiation on the diffusion length of minority carriers in wide-band-gap semiconductors
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Von Roos, O.↗
GSFC optical ozonesonde results during the Gap, France, intercomparisons, June 1981
O3 soundings made with balloon-borne optical sensors during the French Intercomparison Ozone Campaign in June, 1981, are reported. The GSFC four-channel UV-filter-photometer ozonesonde designed for the Super Loki rocket was attached to the gondola roof for redundant O3-density measurements at altitudes of 22-32 km, using the 300 and 303-nm filters. Sensor calibration, data processing, input constants, and vertical O3-distribution calculations are discussed. The density profiles for three legs of the flight, calculated using Bass or Vigroux cross sections, agreed within a standard error of 1.4 percent for each channel, but showed a consistent 4-5 percent (significant) difference between channels. Total average O3-column amounts determined by combining the GSFC data with ECC measurements for altitudes below 21 km were in good agreement with bias-corrected TOMS data from Nimbus-VII and with ground-based data from the Observatoire de Haute-Provence at Mt. Chiran, when the latter were computed using the pre-campaign calibration. A 9-percent discrepancy arose when the Chiran data were corrected for a post-campaign recalibration of the Dobson spectrophotometer.
Krueger, A. J.↗
The breakdown of nuclear quasi-equilibrium in highly compact binaries and the origin of the 2-3 hour gap in the orbital period distribution of cataclysmic variables
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Joss, P. C.↗
The formation of aligned spheres in miscibility gap systems
The development of regularly sized and spaced rods or spheres in a monotectic system is presently considered in terms of interface breakdown and capillary instability mechanisms between two liquid phases. The most important relationship, which governs the rod-to-aligned spheres transition, is the temperature gradient-to-growth rate ratio that determines the depth of the intercellular nodes. Rods will develop when these nodes are shallow by comparison to rod circumference, and spheres will develop when they are deep.
Schafer, C.↗
Heat-Shield Gap Filler
Ceramic cloth strips provide flexible, easily replaceable insulating filler. Filler prevents hot gas from flowing between heat-shield tiles while allowing space for thermal expansion and contraction. Strips easily replaced when necessary.
Leiser, D. B.↗
Controls of Intracellular Communication Mediated by Gap Junctions
Experiments were done using aequorin and no increase in aequorin luminescence during acidification adequate to uncouple cells was seen. The pH sensitivity of the conductance of the perfused membrane was essentially the same as that observed with intracellular pH microelectrodes.
Bennett, M. V. L.↗
Regeneration efficiency, shuttle heat loss and thermal conductivity in epoxy-composite annualr gap regenerators from 4K to 80K
A test apparatus designed to simulate a section of a Stirling cycle cryocooler was built. Measurements of regeneration efficiency, shuttle heat loss and thermal conductivity reported for several regenerator test sections. The test composites were epoxy glass, epoxy glass with lead particles, epoxy glass with activated charcoal and epoxy graphite. Losses measured for these materials were approximately the same. Losses are in good agreement with those calculated theoretically for an epoxy glass (C-10) composite. The implications of these results on cryocooler design are discussed.
Myrtle, K.↗
Experimental determination of gap flow-conditioned forces at turbine stages and their effect on the running stability of simple rotors
Instabilities in turbine operation can be caused by forces which are produced in connection with motions involving the oil film in the bearings. An experimental investigation regarding the characteristics of such forces in the case of three typical steam turbine stages is conducted, taking into account the effect of various parameters. Supplementary kinetic tests are carried out to obtain an estimate of the flow forces which are proportional to the velocity. The measurements are based on the theoretical study of the damping characteristics of a vibrational model. A computational analysis of the effect of the measured fluid forces on the stability characteristics of simple rotor model is also conducted.
Wohlrab, R.↗
Surface step induced gap heating in the Shuttle Thermal Protection System
Previously cited in issue 5, p. 606, Accession no. A83-16533
Petley, D. H.↗
Retrofitting avionics - Closing the performance 'Generation gap'
The retrofitting of advanced avionics to in-service aircraft in order to increase operational safety and flexibility, and reduce operating costs is analyzed. Research in flight management planning and airborne guidance for full-and cost-effective flight is examined. The use of CRTs and thin film electroluminescent displays in aircraft is described. The development of more accurate and reliable fuel gauges using nuclear-based techniques or volumetric measurements to evaluate fluid levels is studied. Advances in airspace systems, such as the Microwave Landing System, and Air Traffic Control Beacon System/Select Mode, the Traffic Advisory and Collision Advance System, and satellite-based communications, navigation, and surveillance are discussed.
Spitzer, C. R.↗