Materials Literature
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(Sc 0.35 Ti 0.65 )Fe 2 having the hexagonal Laves phase structure is a ferromagnet with the Curie temperature of 360 K. The ferromagnetic moment changes from 1.3 to 0.9 µ B around 70 K with increasing temperature. The transition is of the first order. The longitudinal stiffness constant for spin fluctuations changes a…
Filters which serve as dichroic beam dividers are useful for certain types of far-infrared photometer. We have used inductive cross metal mesh as reflective coatings on solid dielectric Fabry-Perot etalons to produce dichroic filters with quality factors in the range 3 < Q < 10. These filters reflect strongly at…
Studies of grain structure, size, distribution, and geometric arrangement are gaining importance especially from the point of view of thin-film interconnects for micron and submicron semiconductor technologies. We have studied the effect of annealing on the grain growth characteristics of pure Al films. As-deposited f…
The specific heats of liquid Se-Te alloys have been measured as a function of temperature. There have been large and maximum values in the specific heat curves of liquid Se 1- x Te x ( x =0.2, 0.3 and 0.4) alloys. They are explained in terms of Schottky-type specific heats due to the transition from non-metallic two-f…
The behavior of carbon atoms in relation to oxygen precipitation in Czochralski silicon crystals subjected to various heat treatments is investigated by means of infrared (IR) spectroscopy. It is shown that carbon atoms enhance and modify oxygen precipitation both at 750 and at 1000 °C. Perturbed [Oi−Ci] C(3) centers,…
We develop continuum elastic theories for the blue phases of cholesteric liquid crystals and for the metallic glasses. These theories are frustrated and possess ground states with networks of defect lines; the frustration can be relieved in a space of constant positive curvature (a sphere in four dimensions). The orde…
The electrical conductivity of the solid electrolyte \ensuremath{\alpha}-${\mathrm{Li}}_{2}$${\mathrm{SO}}_{4}$ is investigated for the temperature range 580--800 \ifmmode^\circ\else\textdegree\fi{}C and for pressures up to 0.6 GPa. The migration enthalpy at normal pressure is 0.45\ifmmode\pm\else\textpm\fi{}0.05 eV,…
Abstract The transverse relaxation rate of H 2 O in Al(H 2 O) has been measured as a function of temperature (255 to 417 K) and pressure (up to 220 MPa) using the 17 O‐NMR line‐broadening technique, in the presence of Mn(II) as a relaxation agent. At high temperatures the relaxation rate is governed by chemical exchan…
Two satellites on the high-energy side of the K emission band of graphite have been observed and found to be anisotropic. One of them is attributed to the radiative decay of double ionization of the K shell while the other is tentatively explained as resulting from electronic transitions from the conduction-band minim…
The surface tension γ is calculated in the mean field approximation in the system of rod-like molecules interacting via attraction as well as hard-core repulsion. It is found that the excluded volume effect favours the normal alignment of molecules at the free surface. The molecular orientations observed at the free s…
Enhanced quantum efficiencies have been obtained for Au-InP internal photoemission detectors using grating coupling of incident radiation into surface plasma waves confined to the air-metal interface. Enhancements of over a factor of 30 are observed at the resonance coupling angles. A model calculation of the surface…
The first-neighbor distances in the ionically bonded rocksalt-structured solid solutions (${\mathrm{K}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{Rb}}_{\mathrm{x}}$)Br and Rb(${\mathrm{Br}}_{1\mathrm{\ensuremath{-}}\mathrm{x}}$${\mathrm{I}}_{\mathrm{x}}$) differ substantially from the average, or virtual-crystal,…
Knowledge of the thermal conductivity of boron carbide is necessary to evaluate its potential for high-temperature thermoelectric energy conversion applications. We have measured the thermal diffusivity of hot-pressed boron carbide ${\mathrm{B}}_{\mathrm{x}}$C samples as a function of composition (4\ensuremath{\le}x\e…
CuInSe2 photoanodes can be optimized for use in electrochemical photovoltaic cells, containing aqueous polyiodide as the electrolyte, by wet chemical etching in Br2MeOH and subsequent thermal treatment (air oxidation). Surface analyses show the formation of a rather clean, Cu-depleted surface with some adsorbed oxygen…
We show that the anchoring energy function, i.e., the anisotropic part of the interfacial free energy, at a nematic liquid crystal-wall interface can be determined uniquely without a numerical fitting procedure, when the integrated birefringence of a liquid crystal cell with a thickness much larger than the extrapolat…
A theoretical calculation of the electronic contribution to the thermal conductivity ( lambda e ) of narrow band gap semiconductors is presented which takes into account the non-parabolic nature and multivallied structure of the energy bands including intervalley scattering. The analysis indicates a significant reduct…
A NATO Advanced Study Institute on Fundamentals of Transport Phenomena in Porous Media will be held July 14–23, 1985, in Newark, Del. Directors of the institute are Jacob Bear, Department of Civil Engineering, Technion‐Israel Institute of Technology, and M. Yavuz Corapciogiu, Department of Civil Engineering, Universit…
It is believed that covalent glasses can be divided into two classes: those with high average coordination (amorphous solids) and those with low average coordination (polymeric glasses). We present the first conclusive evidence that this division is correct by calculating the elastic properties of random networks with…
A quasi-crystalline solid is an aperiodic array of atoms which gives rise to Bragg-like diffraction peaks. Using the projection method for generating such structures, the authors provide a simple derivation of this paradoxical behaviour.
The Peierls transition in the quasi-one-dimensional conductor K 0.3 MoO 3 has been studied to clarify its dynamical nature and the electron correlation problem. A giant Kohn anomaly and the central peak in S(q, omega ) were observed. The amplitude below the transition temperature T c was also measured. An asymmetry of…