Materials Literature
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Solid cylindrical specimens (½- × ½-in.) of the monocarbides of Ti, Zr, Ta, Nb, and W, made by 1) hot pressing, 2) slip casting and sintering, and 3) explosion-pressing and sintering, were irradiated at 300 to 700°C. Fast-neutron (> 1 MeV) exposures ranged from 0.8 to 5.4 × 1021 n/cm2 in a fast-neutron flux profile wh…
In the usual contact plants 97-98% of the SO2 is oxidized to SO3 while the remaining 2-3% nonoxidized S02 are emitted. The stack gas generally contains 0.2-0.3% by volume SO2.Through changing to the Bayer Double Contact process, the conversion can be raised to 99.5% or higher. The sulfuric acid can be produced at the…
Abstract A series of well‐characterized polyamic acids from pyromellitic dianhydride and 4,4′‐diaminodiphenyl ether of systematically varied molecular weight and known molecular weight distribution were chemically converted to polyimide films under regulated conditions. The films were essentially noncrystalline, of mo…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHigh-spin, five-coordinate cobalt(II) complexesZvi Dori and Harry B. GrayCite this: Inorg. Chem. 1968, 7, 5, 889–892Publication Date (Print):May 1, 1968Publication History Published online1 May 2002Published inissue 1 May 1968https://pubs.acs.org/doi/10.1021/ic50063a010https…
ABSTRACT The validity of boron in illite as a salinity indicator has been questioned recently. Using analytical data from whole rocks, some workers argue that illite is predominantly detrital and inherits much of its boron from the parent rocks. They also believe that additional boron, absorbed at the time of depositi…
Abstract Two crystalline forms (α and β) of poly(vinylidene fluoride) were studied by infrared spectroscopy. The spectral differences permitted the study of the transformation and the ratio of the two forms. The ordinary \documentclass{article}\pagestyle{empty}\begin{document}$ \vec G,\vec F $\end{document} matrix met…
Based upon a thermodynamic study of the accelerated oxidation of superalloys exposed in oxidizing environments containing minor quantities of sea salt, it is concluded that (a) NaCl is necessary only to form Na2SO4, (b) Na2SO4 is formed by the reaction between NaCl and the oxides of sulfur, (SO2 and SO3) and (c) accel…
The complex dielectric constant of NaNO 2 crystal was measured in a frequency range between 1 MHz and 24 GHz from room temperature to 210°C. The measuring methods in the various frequency ranges were described in detail and especially the measuring accuracies in the complex dielectric constant and the temperature were…
A simple, rapid‐quenching device was used to investigate the extent of liquid‐liquid immiscibility in the system BaO‐SiO 2 . A metastable miscibility gap was found with an upper consolute point at about 10 mole % BaO and 146OOC. Bulk glass samples of different compositions and heat treatments were examined by direct‐t…
Abstract It has been known that cyclohexanol has low-temperature form (crystal-II) and high-temperature form (crystal-I) and that the supercooled crystal-I shows in its heat capacity curve an anomalous jump resembled to that associated with glass transition. In order to clarify whether this anomaly arises from relaxat…
An experimental technique using powders is described which permits the rapid classification of materials according to(a) magnitude of nonlinear optical coefficients relative to a crystalline quartz standard and(b) existence or absence of phase matching direction(s) for second‐harmonic generation.Results are presented…
Abstract An einem ZnO‐Kristall kann man sensibilisierte Photoströme beobachten, wenn man ihn in Kontakt mit einem Elektrolyten bringt, dem ein geeigneter Farbstoff zugesetzt ist, und seine Oberfläche mit Licht einer Wellenlänge bestrahlt, das nur vom Farbstoff absorbiert wird. Der ZnO‐Kristall muß als Anode einer galv…
Electric or magnetic fields acting on the anisotropy of the electric or magnetic susceptibility exert torques within a liquid crystal which may compete with the elastic torques determining its internal structure. A general method is presented for calculating the structural changes thus produced. Two examples are given…
Carbon was deposited on virgin, natural diamond powder from methane gas at 1050°C and 0.3 Torr. The deposits were identified as new diamond by chemical analysis, chemical etching, density measurements, x-ray and electron diffraction, microwave absorption, electron spin resonance, and visual observations. The crystalli…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe molecular and crystal structure of porphyrin diacidsAllen Stone and Everly B. FleischerCite this: J. Am. Chem. Soc. 1968, 90, 11, 2735–2748Publication Date (Print):May 1, 1968Publication History Published online1 May 2002Published inissue 1 May 1968https://doi.org/10.102…
CONTENTS I. Introduction 298 II. Contrast in the electron microscope, and methods of increasing the contrast 298 III. Structural studies of polymers using contrast intensification methods. Effect of contrast materials 303
Introduction 453 1. The Dynamic Approach to the Problem of Ferroelectricity 454 1.1. Lattice Dynamics and Stability of Non-piezoelectric Crystals 455 a) General Vibration Equations and the Condition of Structural Stability 455 b) Dielectric Properties of Crystals and Their Relation to the Characteristic Frequencies 45…
It is shown how the correct tensors for the description of the rigid-body motion of molecules in crystals can be obtained from a lattice dynamical calculation. This helps in understanding the tensor S introduced in the paper by Schomaker & Trueblood (Acta Cryst. (1968). B24, 63). An expression for the anisotropic temp…
Electron spin resonance (ESR) studies have been made of gamma-irradiated Nb2O5–Na2O–SiO2 glasses. The samples received a gamma-irradiation dose of 2 × 107 R at liquid-nitrogen temperature, and were investigated at that temperature. A broad spectrum which is characterized by an axially symmetric g tensor and hyperfine…
Spin reorientation due to change in sign of the temperature-dependent anisotropy energy has been studied in ${\mathrm{Mn}}_{2\ensuremath{-}x}{\mathrm{Cr}}_{x}\mathrm{Sb}$ ($x=0 \mathrm{and} 0.03$) by nuclear spin echo measurements. The behavior of the dipole and quadrupole hyperfine interactions and ${T}_{2}$ is repor…