Materials Literature
按标题、摘要、年份、主题和来源检索公开元数据。结果保留作者、摘要、分类与原始来源链接。
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…
Excitation and luminescence emission spectra of NaI(Tl) single crystals with high Tl content (>0.1 mole%) have been analyzed as a function of temperature and concentration. At high Tl concentrations, both single and dual Tl centers influence the optical properties of the crystal. We have found evidence that energy…
An investigation of some of the characteristics of the thallous double center (dimer) in NaI: Tl was carried out over the temperature range 15 to 300\ifmmode^\circ\else\textdegree\fi{}K and for thallium concentrations of 0.08 to 1.01 mole% Tl. A measurement of the lifetime of the dimer excited state resulted in a valu…
Relativistic augmented-plane-wave calculations for Gd, Dy, Er, and Lu are reported. Energy bands, histograms of the density of states, and Fermi-surface cross sections are given. The Fermi surfaces of Dy, Er, and Lu are found to be quite similar to the one given earlier for yttrium. The Fermi surface of Gd is found to…
19 F nuclear magnetic resonance signals of aqueous solutions containing beryllium and fluoride ions have been used to study the equilibrium and kinetic processes occurring. Detailed studies of line widths, intensities, chemical shifts, and coupling constants have been made. This leads to an equilibrium constant determ…
The fluorescence of phosphors NaLn1–xEuxTiO4(Ln = La, Gd, Y, Lu) with ordered Sr2TiO4 structure is reported. The unactivated host lattices show broad-band emission peaking at about 450 nm. The quenching temperature of this fluorescence is below room temperature. The relative intensities of the Eu3 + emission lines dep…
The crystal structure of Sc 2 O 3 (C-type; a 0 = 9.8459 ± 15 Å at 20 ± 2 °C) was refined from X-ray powder diffractometer data. Isotropic individual temperature factors were used in full-matrix F (19 reflections) and F 2 (41 reflections) programs. The positional parameters were determined as u(Sc) = −0.0355 ± 1, x(O)…
Raman scattering from crystalline NaNO3 has been observed in all polarization orientations. Except for small intensity contributions in some orientations which are probably due to depolarization effects in the birefringent crystal, the polarizability activities of both internal and external modes follow the expected s…