Materials Literature
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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…
Discusses all aspects of coating technology, including how coatings are prepared, their compositions, how they are applied, and the conditions that control their ultimate performance. Covers the newest coating applications, particularly those developed to enhance energy savings and conform to pollution regulations. Wr…
ABSTRACT Advantage of the application of high strength steels to offshore structures was investigated on the basis of fatigue strength. It was concluded that the tethers of a tension leg platform are one of the typical structural components which can make the best use of a high strength steel. Basic corrosion fatigue…
Refractive-index and linear-birefringence measurements on $\mathrm{K}{\mathrm{Ta}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{x}{\mathrm{O}}_{3}$, with $x=0.008, 0.012, \mathrm{and} 0.02$, reveal smeared phase transitions into long-range order. In accordance with previous caloric, second-harmonic---generation, dielectric, and x…
Many of the early transition elements form large polynuclear metal-oxygen anions containing up to 200 atoms or more. Although these polyoxoanions have been investigated for more than a century, detailed studies of structure and reactivity were not possible until the development of modern x-ray crystallographic and nuc…
In the study of the fundamental mechanism of growth and nucleation of a crystal from an aqueous solution, it is essential that the structural nature of the supersaturated liquid be as well understood as possible. It is suspected that the species diffusing to the surface of growing crystals are not single ions but eith…