Materials Literature
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The hyperfine structure (hfs) and spin-lattice relaxation in the excited $\overline{E}(^{2}E)$ states of ${\mathrm{V}}^{2+}$ and ${\mathrm{Mn}}^{4+}$ in ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$ have been studied by optical-detection techniques. This is an extension of an earlier study of EPR (electron paramagnetic resona…
The sharp absorption spectrum of antiferromagnetic ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ is investigated. The molecular-field approximation to the exchange interaction is shown to be inapplicable to the $^{2}E$ states. A modified exchange interaction is introduced via an effective Hamiltonian, and the resulting transi…
The impurity ion ${\mathrm{S}}_{2}^{\ensuremath{-}}$ has been introduced into six alkali-halide crystals: NaI, KCl, KBr, KI, RbBr, and RbI. The center is characterized by extreme $g$ anisotropy; in KBr, for example, the principal $g$ factors were 3.5037, 0.8434, and 0.8388. The first of these corresponds to the S-S bo…
Expressions for the temperature dependence of the magnetoelectric susceptibility parallel and perpendicular to the trigonal axis in ${\mathrm{Cr}}_{2}$${\mathrm{O}}_{3}$ are presented. A two-sublattice model is used. The relation between the sublattice magnetization and the temperature is derived from experimental res…
Measurements of electron-bremsstrahlung cross sections have been made for incident electron energies of 1.0, 1.7, and 2.5 MeV and targets of Al, Cu, Sn, and Au. Data are included at angles of observation from 0\ifmmode^\circ\else\textdegree\fi{} to a limiting angle including more than 90% of the total emitted bremsstr…
Toller's group-theoretical analysis of kinematics is exploited to define a complete set of variables, each of independent range, for particle production of arbitrary multiplicity. In terms of these variables, the generalized Regge-pole hypothesis leads to a simple, unambiguous, and experimentally accessible prediction…
M\"ossbauer-effect measurements in external magnetic fields show that the magnetic structure of ferrimagnetic Ni${\mathrm{Fe}}_{2}$${\mathrm{O}}_{4}$ is the collinear N\'eel type. Ni${\mathrm{Fe}}_{0.3}$${\mathrm{Cr}}_{1.7}$${\mathrm{O}}_{4}$ is shown to have a triangular structure with ${\ensuremath{\theta}}_{A}=20\i…
Experimental optical third-harmonic coefficients for inert gases are presented and compared with experimental Kerr coefficients and theoretical dc hyperpolarizabilities.Received 12 June 1967DOI:https://doi.org/10.1103/PhysRevLett.19.556©1967 American Physical Society
Essigsäurelösung bis zur Entfärbung titriert.Darauf gibt man 70 ml einer 0,5-n.methanolischen Jodlösung (Zusatz von 5 g KJ pro 100 ml) zu; man rührt weitere 10 Stdn.bei -40 °C und noch 2 Stdn.bei Zimmertemperatur.Das überschüssige Jod wird mit Natriumthiosulfat zurücktitriert.Die Lösung wird mit Natriumbicarbonat vers…
A study has been made of the wear of various hard steels sliding unlubricated in dry air and in dry carbon dioxide at temperatures up to 500°C. Over the range of loads and speeds employed the wear is of a mild character and the wear debris is of oxide particles, no metallic debris being formed. The characteristics of…
Films of As2Se3 and Sb2Se3 and their mixtures have been studied by electron microscopy and diffraction. On heating amorphous As2Se3 films no change occurs, but the Sb2Se3 films and mixtures of Sb2Se3 and As2Se3 transform to give small single crystals. These crystals have their c axes parallel to the substrate and give…
EXPERIMENTAL INVESTIGATION HAS PROVED THE RELATIONSHIP BETWEEN SIZE AND SHAPE OF TEST SPECIMENS - CYLINDERS AND PRISMS - AND THE DIRECT TENSILE STRENGTH OF CONCRETE. ALTHOUGH TWO DIFFERENT GRADES OF CONCRETE WERE TESTED WITH RIVER PEBBLES AND WITH GRANULATED AGGREGATES, NO ESSENTIAL DIFFERENCE WAS FOUND IN THE CURVE O…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAmmonia in auto exhaustJohn H. Harkins and Stephen W. NicksicCite this: Environ. Sci. Technol. 1967, 1, 9, 751–752Publication Date (Print):September 1, 1967Publication History Published online1 May 2002Published inissue 1 September 1967https://pubs.acs.org/doi/10.1021/es6000…
A computer expression for predicting the shielding effectiveness of an infinite plane shield has been developed for low frequencies (below 50 kHz). It is shown that this expression, which arises as a special case of the solution of the general wave equation, is a sum of the attenuation term of Schelkunoff's transmissi…
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The effect of stress relaxation by creep on the thermal stress fracture of brittle ceramics at high temperature under conditions of quasi‐static heat flow is discussed. It is shown that, to a good approximation, thermal stress relaxation rates can be calculated on the basis of creep rates which correspond to the minim…
Summary A number of new alkaline-earth-rare-earth silicate and germanate compounds with the apatite-type structure have been synthesized including a new calcium lanthanum silicate, Ca 4 La 6 (SiO 4 ) 6 (OH) 2 , which has a 9·63 Å, c 7·12, and c/a 0·740. This has a random distribution of Ca 2+ and La 3+ over the (4f) a…
Summary The immediate Q/I relation of K in a soil relates the amount of labile K present to its chemical potential, measured relative to the chemical potential of (Ca+Mg) in the same soil. The present work shows that the form of the Q/I relation is almost unchanged either by large additions of K, up to 3750 kg K 2 O/h…
A two-valence-band model and the theory of transport in semiconductors with non-parabolic bands have been used to explain the carrier concentration dependence of the room-temperature thermoelectric power and below-room-temperature Hall mobility of undoped and Na-doped PbTe. It was assumed that the scattering is by lat…
Considerable x-ray diffraction analysis of omega phase in titanium alloys has been reported; however, little direct observation of its occurrence via electron microscopy has been published. In this work we have demonstrated by means of transmission electron microscopy that the omega phase in titanium-35% niobium preci…