Materials Literature
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The electronic structure of cubo-octahedral and icosahedral ${\mathrm{Au}}_{13}$ clusters has been investigated by the self-consistent-field molecular-orbital Dirac scattered-wave method. Double-point-group--symmetry considerations indicate that the icosahedral cluster will undergo static Jahn-Teller distortion, while…
The initial stages of magnesium oxidation are investigated by high-resolution electron-energy-loss spectroscopy. Two species (magnesium oxide and chemisorbed oxygen) are simultaneously detected from their vibrational bands even for minimal oxygen exposures. The evolution of the surface oxide can be quantitatively desc…
There is a considerable disagreement in the literature on the description of lifetime effects arising from core-valence transitions in solids. We calculate here Auger and radiative widths of shallow core levels in Li, Be, Na, Mg, and Al with use of principles consistent with dynamical theories of secondary-emission pr…
The structural characteristics of Sr1−x Lax TiO3+δ (0≤x≤0.4) at 1400 °C have been investigated as a function of ambient oxygen partial pressure. A modified Rietveld pattern-fitting structure-refinement program [H. M. Rietveld, J. Appl. Crystallogr. 2, 65 (1969)] was used to determine the nature of the distortions of t…
A new electron trap, labeled ED1, with an activation energy of 0.68 eV has been found to appear in the deep-level transient spectroscopy spectrum of n-type GaAs crystals as a result of their plastic deformation at 400 °C. The trap has been systematically investigated taking into account broadening of its energy level.…
An experimental study of the temperature- (T-) dependent dc and audio-frequency conductivity (\ensuremath{\sigma}) as a function of protonation level (0.0\ensuremath{\le}x\ensuremath{\equiv}[${\mathrm{H}}^{+}$]/[N]\ensuremath{\le}0.08) of emeraldine polymer is presented. The dc conductivity varies from ${10}^{\mathrm{…
Lead zirconate-titanate (PZT) thin films with tetragonal and rhombohedral structures have been successfully grown with good epitaxy on MgO single crystals and on [100]-oriented platinum thin films by rf-magnetron sputtering. The PZT films were obtained by using sputtering targets with compositions of Pb(ZrxTi1−x)O3, w…
The conductivity and dielectric constant of the emeraldine polymer are studied at a frequency of 6.5\ifmmode\times\else\texttimes\fi{}${10}^{9}$ Hz as a function of temperature T and protonation levels spanning from insulating emeraldine base [${\ensuremath{\sigma}}_{\mathrm{dc}}$(295 K)\ensuremath{\approxeq}${10}^{\m…
Theoretical calculations are presented for the figure of merit Z in thermoelectrics. The maximum values of Z are obtained in semiconductors which are doped so that the chemical potential is near the band edge. The highest Z is related to the B parameter of Chasmar and Stratton [J. Electron. Control 7, 52 (1959)].
We have developed an addition to the Steinberg–Guinan high strain-rate constitutive model that extends its validity to strain rates as low as 10−4 s−1. With this new model, we have successfully reproduced a number of rate-dependent, shock-induced phenomena in tantalum, such as precursor on reshock, precursor decay, an…
A simple extension of the Monkhorst-Pack Fourier-quadrature (or special-points) method for Brillouin-zone integration makes it possible to determine equivalent (identical by symmetry) points for two different unit cells simply by identifying lattice points common to both cells. This is useful for superlattice or super…
The nonlinear refractive indices (${n}_{2}$) of a large number of optical crystals have been measured at a wavelength near one micrometer with use of nearly degenerate three-wave mixing. The measurements are compared with the predictions of an empirical formula derived by Boling, Glass, and Owyoung. This formula, whic…
Abstract The binuclear Mn(III) complexes (I) and (VI) from Mn(III) acetate, sodium acetate, and the corresponding cyclic triamine undergo disproportionation reactions in aqueous solution under anaerobic conditions producing a variety of novel binuclear Mn(III),Mn(IV) and Mn(IV),Mn(IV) dimers such as (II), (IV), (VII),…
Several ferroelectric properties of triglycine sulphate single crystals both pure and with different doping substitutions in the structure have been studied in the vicinity of the critical point T c . The parameters engaged in the statistical dipolar theory of ferroelectrics are derived, from dielectric constant and h…
Recent Monte Carlo studies have demonstrated the existence of positionally ordered phases in systems of monodisperse, parallel hard spherocylinders. We present an excluded-volume theory of this system which utilizes a scaled-particle treatment of dimensions possessing full translational freedom combined with a simple…
It has been possible to identify two critical compositions in the IV-VI chalcogenide glassy system ${\mathrm{Ge}}_{x}{\mathrm{Se}}_{100\ensuremath{-}x}$ by the anomalous variations of the high-pressure electrical resistivity behavior. The first critical composition, the chemical threshold, refers to the stoichiometric…
This book will be useful to those involved in optical transmission and scanning electron microscopy (SEM) studies of polymers. The chapters include methods for morphological investigations and determination of fine structure (crystallinity, orientation) in various types of polymers and polymer blends. The effects of p…
ABSTRACT In order to protect production tubing from corrosion during acidic stimulation treatments at temperatures above 250°F (121°C), inhibitors containing heavy metals (copper, arsenic or antimony) have been employed. These metallic inhibitors are the subject of increasing regulatory control in the US and abroad. A…
Abstract Five structurally different scale inhibitors were studied using a kinetic adsorption-desorption technique. Adsorption was fast. All inhibitors adsorbed to a similar degree. Desorption was slow. There were large differences in the degree to which different inhibitors desorbed. The kinetic desorption characteri…
Abstract The occurrence of calcium sulfate scale in wells has recently become a sporadic major problem in producing wells in some CO2 floods.1 The problem has also been observed in wells where a potential scaling factor exists and the produced water has more than a fraction of a percent of carbon dioxide gas. Where ca…