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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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Transmission measurement of neutrons by filter materials for low energy neutrons is important for the study of structure and dynamics of condensed matter. Since only thermal neutrons are useful for such experiments, filter materials that transmit thermal neutrons while attenuating fast neutrons and gamma rays are of considerable interest.
Hot salt stress corrosion cracking of titanium-aluminum alloys
Thermionic converter with fluorine vapor deposited tungsten emitter etched to expose crystal planes
Fluidized bed processing of fluorinated irradiated reactor fuels
Molecular He and Ar nozzle-type beams scattering from room temperature LiF crystal surfaces, measuring particles flux and speed distributions
Group 4A difluorides vaporization thermodynamics and bond dissociation energies, tabulating mass spectra, vapor composition, reaction enthalpies, heats of polymerization and thermodynamic functions
Trapped Ag atoms production in silver nitrate ice by gamma irradiation, discussing reaction enhancement by flouride ion
Electrochemistry of freshly generated titanium surfaces and stress corrosion cracking in aqueous solutions and in molten salts
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A large-area Bragg spectrometer used to search for the Fe XXV X-ray emission lines of Sco X-1 is described. The device has 3400 sq cm of LiF on nine crystal panels aligned perpendicular to the longitudinal axis of the rocket. X rays satisfying the Bragg condition reflect into an array of nine companion proportional counters. A pointing system incorporating a free gyroscope with 2 degrees of freedom assures that target X rays are reflected at the required angle and produces repeated spectral scans of the X-ray continuum, which are later superimposed to correct temporal effects. The instrument is capable of detecting a narrow line flux from Sco X-1 of about .01 photons/sq cm/sec.
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Some potential energy curves for CF2O were calculated using projected-unrestricted Hartree-Fock (PUHF) theory. The calculations employed a contracted (4s 3p) Gaussian-type atomic orbital basis set. Bound states were found for the X-tilde 1A1 and 1,3A2 states while the 1,3B1 and 1,3B2 states were repulsive in the valence representation. The merits of the PUHF treatment for excited states are discussed. The results are discussed in terms of available experimental information and previous calculations with particular emphasis on the question of the photolysis channels open in the solar spectral region.
Simple chemical process makes synthetic cryolite by utilizing byproducts of one kind of silicon production process. Potential result of commercialization could be economic benefit to silicon industry or to aluminum industry, in which cryolite is used as flux.
Silion is withdrawn from bottom of crucible, once two immiscible liquid stages form, in quasi-continuous method of separating silicon from other reaction products. Process is periodically halted to remove accumulated buildup of salts.
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The influence of OH ion impurities on thermoluminescent sensitivity and supralinearity in LiF:Mg, Ti is analyzed. Available evidence is shown to be consistant with the presence of Ti-OH and Mg-OH complexes. The track interaction model is used to explain the data, with competing centers decreasing sensitivity and supralinearity at high concentrations.
Optical pumping of a holmium:yttrium lithium floride (Ho:YLF) crystal with a 790-nm continuous-wave diode-laser array has generated 56 mW of 2.1-micron laser radiation with an optical-to-optical conversion slope efficiency of 33 percent while the crystal temperature is held at 77 K. The lasing threshold occurs at 7 mW of input power, and laser operation continues up to a crystal temperature of 124 K.
Damage in ZrF4-BaF2-LaF3 glass induced by high-energy electrons was studied by ESR and optical spectroscopy. An optical absorption band at 314 nm in the irradiated glass annealed rapidly above about 50 C, probably by a second-order reaction at room temperature; the ESR lines annealed very slowly at room temperature.