Materials Literature
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The reflectivity of metallic films, as calculated from standard equations, is discussed in the case of infrared radiation. We derive the minimum thickness of a metallic film for infrared reflectors and show the reason that metallic films cannot be used to make Fabry-Perot filters in the infrared.
We start with a multipole expansion of the London-van der Waals dispersion forces between elongated cylindrically symmetric molecules as a model for the two-particle interaction. This potential is rotationally invariant and anisotropic due to both the orientation and the position of two molecules. In the next step we…
Infrared and Raman spectra of polycrystalline lithium metasilicate have been recorded. A vibrational assignment in terms of the various symmetry species of the unit cell group, C 2v , has been made. A normal coordinate analysis of the unit cell vibrations at the centre of the Brillouin zone (k = 0) was carried out to…
An apparatus is described for generating and assessing foams in digestive fluids in vitro. The effects of caraway, cinnamon, dill, orange and peppermint oils on gastric and intestinal foams were examined. Reductions in foam volume were observed in every case, although the effects were not as great as those produced by…
Submillimeter-wave modulators and switchable polarizers have been fabricated from VO2 thin films deposited on sapphire substrates. By passing electric current pulses through elements made from these films, the films can be thermally cycled through the insulator-to-metal transition that occurs in VO2 at about 65 °C. In…
A thermodynamic model of hysteresis in phase reactions based on regular solution theory is developed by invoking metastabilities. The effect of enthalpy and entropy change, pressure, temperature, and interaction energy on the hysteresis curve term is explored. The influence of a variation of the interaction term with…
An improved model explains the hot salt stress corrosion cracking (HSSCC) of titanium alloys. Basically, corrosion produced hydrogen from a secondary cathodic reaction is responsible for the premature failure which can occur when tensile stressed titanium alloys are exposed to chloride containing hot salt environments…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA ferromagnetically coupled chromium(III) dimer: synthesis, structure, and magnetic properties of sodium di-.mu.-hydroxo-bis[bis(malonato)chromate(III)] pentahydrateRaymond P. Scaringe, William E. Hatfield, and Derek J. HodgsonCite this: Inorg. Chem. 1977, 16, 7, 1600–1605Pu…
Reflectivity spectra of lead telluride epitaxial layers on BaF2 and NaCl substrates have been investigated in the wave-number range of 5–100 cm−1. Due to multiple reflections and interference effects in the sandwich samples, weak structures in the reflectivity spectra are accentuated. This leads to a more precise dete…
The reaction of aryl halides with hexamethyldisilane \nand potassium methoxide (or sodium methoxide or \nmethyllithium) in hexamethylphosphoric triamide (HMPT) \naffords the corresponding trimethylsilyl-substituted benzene \nand some reduction product.
Mass attenuation and energy absorption coefficients for 10 keV-100 MeV photons have been calculated for 69 organs and tissues listed in the recent ICRP Reference Man document. Anomalies in the quoted elemental compositions are discussed and comparisons made with the previous Reference Man document published in 1959. T…
The decomposition of nitrous oxide has been studied in the temperature range 1815-3365K using a shock tube technique. Principal results of this study were the determination of the rate constants for the reactions and The experiments were conducted behind incident shock waves in mixtures of N2O and various diluent gase…
Abstract Luminescence centres connected with Bi 3+ and Pb z+ ions are investigated in CaO, SrO, CaS, and SrS crystals at 5 to 300 K. It is found that the ground state and the two lowest excited states of the Bi 3+ as well as the Pb 2+ centres correspond to the energy levels of the free impurity ions and have A 1g , 3…
The nature of the residual stress in steel after uniaxial plastic deformation was investigated magnetically. The B - H curve measured in the residual stress state after elongation was similar to the one under compressive stress, and the induced magnetic anisotropy was uniaxial with the easy axis at right-angles to the…
Elastic moduli of spinel phases in the system Mg(Al, Cr, Fe) 2 O 1 were determined from sonic analyses of porous, polycrystalline specimens prepared by hot‐pressing. A special iterative least‐squares technique (ILS) and standard curve‐fitting techniques were used to obtain moduli at zero porosity by extrapolation. A m…
Calculates the full width at half maximum (FWHM) of the phonon broadening function for Li, Na, K and Al at different temperatures. A theory is used which employs the ionic pseudopotential, rather than, as in Bergersen et al's (1971) theory, a bare Coulomb potential. Despite the fact that a pseudopotential in a general…
This report lists nomenclature recommendations resulting from a six-year study of problems common to the disciplines of mineralogy and crystallography. The recommendations include definitions of polytypism, topotaxy, syntaxy, and epitaxy, certain criteria for mineral names, preferred format for chemical formulae, and…
Pressure-sintered LixNa1−xNbO3 in the range 0.015⩽x⩽0.15 exhibits electromechanical properties amenable to high-frequency device applications with radial-frequency constants fR(r) between 1.75 and 1.95 kHz m, coupling coefficients up to 0.4, and permittivities between 100 and 200. The temperature and time dependencies…
Several aspects of the secondary emission avalanche along an insulator surface (which is believed to play a role in insulator flashover) are addressed theoretically. The saturation condition for the two extremes of supply-limited and space-charge-limited current are obtained in analytic form, and comparison with the c…
The principal Hugoniot of molybdenum has been determined at a pressure of 2.0 TPa by measuring directly both the shock velocity and the particle velocity behind the shock. Neutrons from an underground nuclear explosion were used to generate a high-pressure shock in a slab of molybdenum by rapidly fission heating an ad…