Energy dependence of electron induced radiation damage in tungsten
Electron irradiation energy thresholds for producing damage in polycrystalline tungsten wire
Dicarlo, J. A.↗
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Results for “polycrystalline”
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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The role of anions in mechanical failure
Fabrication and properties of hot-pressed polycrystalline magnesium oxide containing anion impurities
Leipold, M. H.↗
Structure of silicon films deposited on oxidized silicon wafers
Silane for polycrystalline films deposition on oxidized silicon wafers, noting substrate temperature effects on preferred orientation of deposits
Catlin, A.↗
Sub-micron sectioning technique for diffusion experiments
Submicron sectioning apparatus for studying slow carbon self diffusion in dense polycrystalline tungsten carbide
Buhsmer, C. P.↗
Behavior of hydrogen on nickel
Hydrogen adsorption behavior on polycrystalline nickel surfaces, using electron impact desorption flash filament with gas phase and ion spectrometer and vapor deposition
Gilbreath, W. P.↗
Vibrational spectra and structure of biacetyl
Gaseous, liquid and polycrystalline biacetyl vibrational spectra and structure, noting mutual exclusion between IR and Raman radiation
Brown, S. C.↗
Attenuation of seismic waves by grain boundary relaxation
Elastic seismic waves attenuation in polycrystalline ceramics and rocks by grain boundary relaxation, noting strong frequency dependence of earth mantle internal friction
Jackson, D. D.↗
Low frequency vibrations of molecular crystals. XIV - Raman and far-infrared spectra of HNCS and DNCS
Gaseous and solid polycrystalline HNCS and DNCS IR and Raman spectra, studying LF of lattice vibrations
Bragin, J.↗
Infrared and Raman spectra of substituted hydrazines. III - Symmetrical dimethylhydrazine
Comparative IR and Raman spectra of gaseous, liquid and polycrystalline symmetrical dimethylhydrazine and deuterium analogs
Durig, J. R.↗
Creep behavior of electron-beam-melted rhenium
Creep rupture behavior of electron beam melted polycrystalline sheet and powdered rhenium
Raffo, P. L.↗
Ferromagnetic resonance of lunar samples
Ferromagnetic electron spin resonance spectra of Apollo 11 lunar samples, using model for polycrystalline spectra simulation
Chan, S. I.↗
Dimensional-stability studies of candidate space-telescope mirror-substrate materials
The effects of aging, vacuum exposure, and thermal cycling on the dimensional stability of mirror-substrate materials, fused silica, Cer-Vit, Kanigen-coated beryllium, polycrystalline silicon, and U.L.E. fused silica were investigated. A multiple-beam interferometer was used to determine nonrecoverable surface-shape changes of the 12.7-cm-diameter mirrors with substrates of these materials. Thermal cycling and aging in vacuum produced the largest changes, but only a few were as large as 1/30 wavelength, where the wavelength was 632.8 nm.
Jerke, J. M.↗
Metallic transfer between metals in sliding contact examined by auger emission spectroscopy
Metallic transfer between polycrystalline metals in sliding contact was examined. Hemispherical riders of iron, nickel, and cobalt were slid on tungsten, tantalum, niobium, and molybdenum disks in ultrahigh vacuum. Auger emission spectroscopy was used to monitor the elemental composition of the disk surfaces. Iron, nickel, and cobalt transferred to tungsten, whereas only cobalt transferred to tantalum, niobium, and molybdenum. The results of this investigation are discussed in terms of the cohesive energy and strain hardening characteristics of the specimen materials.
Pepper, S. V.↗
Performances of the better metallic electrodes in cesium thermionic converters
Outputs are presented for some cesium diodes having primarily emitters of highly oriented polycrystalline or single-crystal 110 tungsten or .0001 rhenium. Power densities at 10 A/sq cm or 0.5 V appear as functions of emitter temperatures and electrode spacings.
Morris, J. F.↗
Gas Surface Interactions Occurring on Materials Within Ultrahigh Vacuum
The physical adsorption of nitrogen on the chemically cleaned surfaces of Pyrex, 347 stainless steel and polycrystalline nickel was investigated over the pressure range 1 x 10 to the minus 12th power to 3 x 10 to the minus 7th power torr and for temperatures 77.4 and 87.4 K. The adsorption data were linearized by the Dubinin-Radushkevich equation. The metal surfaces were cleaned by electron impact desorption (EID) and the desorbed gases analyzed by mass spectrometry. Work function measurements were also used to indicate changes in the surface condition following an EID dose. At least a monolayer of gas was observed to desorb from the metal surfaces. The isotherms revealed that the metal surfaces were very heterogeneous and that the Pyrex surface had been leached. The calculated isosteric heats of adsorption indicated that the relative order of the physical binding of nitrogen to the solids was 347 stainless steel Pyrex nickel. A relationship was observed to exist in the dynamic technique between the equilibration time and the pressure above the absorbed layer. The slope of the log-log plot of these parameters was found to be sensitive to the surface heterogeneity and may be related to the activation energy for surface diffusion of physically absorbed molecules.
Outlaw, R. A.↗
On the anisotropic elastic properties of hydroxyapatite.
Experimental measurements of the isotropic elastic moduli on polycrystalline specimens of hydroxyapatite and fluorapatite are compared with elastic constants measured directly from single crystals of fluorapatite in order to derive a set of pseudo single crystal elastic constants for hydroxyapatite. The stiffness coefficients thus derived are given. The anisotropic and isotropic elastic properties are then computed and compared with similar properties derived from experimental observations of the anisotropic behavior of bone.
Katz, J. L.↗
Molybdenum work function determined by electron emission microscopy.
A polycrystalline molybdenum sample was recrystallized and thermally stabilized. Quantitative measurements of the emission from each individual grain were obtained with an electron emission microscope. The effective work function for each grain was then calculated. The crystallographic orientation of each grain was determined by Laue back-reflection techniques. A polar plot of effective work function vs crystallographic orientation for the sample was constructed to provide a correlation between effective work function and crystallographic orientation.
Jacobson, D. L.↗
Interaction of sulfur dioxide and carbon dioxide with clean silver in ultrahigh vacuum.
It is shown that when a clean polycrystalline silver surface is subjected to sulfur dioxide at a pressure of 1 nanotorr, sulfur is chemisorbed to the silver. Heating the contaminated silver leads to an estimation of the minimum heat of desorption of 59 kcal/mol. Sulfur Auger peak height and relative function measurements of the surface during exposure show that adsorption occurs during 6 microtorr/sec exposure at 1 nanotorr.
Lassiter, W. S.↗