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A theoretical examination of the electronic energy bands of cubic strontium titanate has been performed by application of the LCAO (linear combination of atomic orbitals) method. Diagonal energies were determined from ionization potentials and crystalline fields based on a point-charge model for the ions. The ionic ch…
Studies on the effects of heat-treating and testing environments for the refractory metals have been limited primarily to the unalloyed metals and a few alloys of columbium and molybdenum. Most of this work has relied on compositional changes as a means of assesing the effects of various environments on these material…
Abstract The examination of a series of high wet modulus fibers by methods commonly employed in studying fiber structure has shown that these methods measure overall molecular accessibility rather than truly crystalline material. The only unequivocal measure of lattice structure is obtained from X‐ray measurements. Th…
Magnetic measurements were made on a spherical single crystal of high-purity stoichiometric MnP with a vibrating-sample magnetometer which was modified to allow precise temperature control and temperature cycling from 4 to 500\ifmmode^\circ\else\textdegree\fi{}K. Anisotropy, saturation magnetization, and susceptibilit…
Lattice constants for face-centered cubic argon determined on a precision x-ray diffractometer were found to be 5.3118 Å at both 4.2 and 15°K, 5.3187 at 21°K, 5.4033 at 64°K, with estimated errors of ±0.0005 Å, and 5.458 at 81°K. Least-squares fitting to a polynomial expression gives, for T≥21°K, a=5.29980+ 5.6389×10—…
The stability relations of calcite, dolomite, and magnesite in aqueous CaCl(2)-MgCl(2)-CO(2) solutions have been determined between 275 degrees and 420 degrees C. Small quantities of the carbonates were allowed to equilibrate with large volumes of aqueous solutions, permitting the approach of phase boundaries from two…
Abstract First, explicit expressions are obtained for the state of stress and deformation due to a periodic distribution of dislocations with respect to three-dimensional space and time. Further, equilibrium conditions for continuously distributed dislocations are derived from the law of energy conservation. The condi…
The ${\mathrm{Mn}}^{55}$ nuclear magnetic resonance has been studied in Mn${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$. The unpulled resonance frequency extrapolated to 0\ifmmode^\circ\else\textdegree\fi{}K is 587 Mc/sec. By studying the effect of an external magnetic field on the resonance it was determined that the main li…
The relative dielectric constant of a series of perovskites such as CaTi${\mathrm{O}}_{3}$, SrTi${\mathrm{O}}_{3}$, BaTi${\mathrm{O}}_{3}$, PbTi${\mathrm{O}}_{3}$, and KTa${\mathrm{O}}_{3}$ has been measured at microwave frequencies over a wide range above the Curie temperature. It was found that a Curie-Weiss law of…
The deformation method is fundamental of the problems of buckling, bending, and simultaneous bending and compression or tension of elastic structures, such as continuous beams, frames, arches, etc. The derivation of the slope-deflection equations of the deformation method and the application of this method in solving…
Abstract Die Dunkelfärbung des frisch hergestellten, hellen Graphitoxids bei Lichteinwirkung beruht auf einer Zersetzung. Schon bei 20°C werden CO und CO 2 entwickelt.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotosensitized cis—trans Isomerization of Methyl OleateA. C. TestaCite this: J. Org. Chem. 1964, 29, 8, 2461–2462Publication Date (Print):August 1, 1964Publication History Published online1 May 2002Published inissue 1 August 1964https://pubs.acs.org/doi/10.1021/jo01031a516h…
The lattice constants and space groups of the selenates of Mg, Mn, Co, and Cu were determined. These selenates all crystallize with the ZnSO 4 structure. Above 40 kilobars and 400°C they all undergo a quenchable transition to the NiSO 4 structure.
Crystallographic analyses of dislocations and dislocation loops in deformed b.c.c. iron observed in the electron microscope have been carried out by applying the electron diffraction theory of contrast at dislocations. Dislocations in deformed iron are in the form of tangles, with interspersed clusters of dislocation…
SrBeO4.4HeO forms
The thermal decomposition of europium hydroxide in an air atmosphere was investigated by means of weight‐loss measurements, infrared spectroscopy, X‐ray diffraction analysis, and electron microscopy. These studies showed that EU(OH)° decomposed at temperatures between 225° and 300°C into EuOOH, which was stable up to…
The consequences of ]-refinement procedures on atoms whose charge distributions are intrinsically non-centrosymmetric are examined in terms of a simple hypothetical structure consisting of two sp a hybrid valence 'prepared' state nitrogen atoms which are centrosymmetrically disposed in a unit cell and asstuned to be v…
Optical absorption and thermoluminescence measurements on untreated crystals of magnesium oxide have shown that the crystals can be divided into two groups. X irradiation of the crystals induces an optical absorption peak at 2.3 ev in group I crystals and at 2.3 and 3.0 ev in group II crystals. Thermoluminescence curv…
The temperature dependence of breakdown field, distribution of time lag. and dielectric constant in high electric field were studied on polycrystalline BaTiO 3 . The d. c. breakdown field is nearly constant in the temperature range 20 to 150°C, on the other band the pulse breakdown field changes markedly near the Curi…
This paper is composed of three parts: 1 Apparatus and method for determination of heat transfer through fabric during flame contact; 2 experimental validation of mathematical analysis and heat flow; 3 application to determination of thermal properties of materials in thin layers.