Materials Literature
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The two long mean-lives observed for positron annihilation in some powders (Al2O3, MgO, SiO2) result from ortho-positronium formation. The longest mean-life corresponds to the triplet-state part that annihilates between the powders grains. Under vacuum, this annihilation is free and one observes the free triplet mean-…
Studies of the nitrogen, deuteron and proton relaxation rates of liquid acetonitrile at various temperatures were carried out by pulsed N.M.R. techniques. Re-orientation of the methyl group about its symmetry axis is found to be approximately ten times faster than the re-orientation of the nitrile group. Analysis of t…
This paper supplements the preceding paper by Maradudin and Vosko on the same subject. Extensions and additions include discussions of (1) the group of the bond, (2) tabulations of the time-reversal invariance criterion, (3) the labeling of experimental dispersion curves, (4) compatibility relations, (5) accidental de…
This paper reviews the extensive work pertaining to the creation of colour centres in alkali halides. After a brief historical survey the various mechanisms put forth to account for defect creation are examined in turn and the experimental evidence which supports or belies each of these is presented. After demonstrati…
Abstract The differences between compounds of carbon and of silicon are discussed, and the role of silicon as a fundamental structural component in inanimate nature is described. Starting with silicic acid and silicates, the structure and properties of the silicones and of compounds having SiCSi skeletons are descri…
G. Agnès, G. P. Chiusoli and G. Cometti, Chem. Commun. (London), 1968, 1515a DOI: 10.1039/C1968001515A
The kinetics of the reaction were determined on single crystal specimens by a gravimetric technique in the temperature range from 1000° to 1120°C at water vapor partial pressures from 1 to 20 Torr. Paralinear rate behavior was observed; i.e. , the reaction rate, which is initially parabolic, eventually becomes linear.…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInhibition of the thermal decomposition of ammonium nitrateGeorge H. Madany and George. BurnetCite this: J. Agric. Food Chem. 1968, 16, 1, 136–141Publication Date (Print):January 1, 1968Publication History Published online1 May 2002Published inissue 1 January 1968https://pub…
Abstract Festkörper liegen bei Zimmertemperatur im allgemeinen nicht im thermodynamischen Gleichgewicht vor. Dies gilt sowohl im Hinblick auf die thermische Fehlordnung als auch im Hinblick auf die von der Komponentenaktivität abhängigen Konzentrationen der Punktfehlstellen. Bei Änderung einer unabhängigen thermodynam…
A new method for the preparation of manganese violet is reported and the formula confirmed as manganese(III) ammonium pyrophosphate by wet analysis, X-ray powder diffraction, infrared spectroscopy, thin-layer chromatography, and magnetic measurements. The thermal decomposition has been studied and thermogravimetric cu…
Die fossilen Diatomeen aus dem Villafranchien bei Senèze (Haute- Loire) wurden bei einer Bohrung durch den Boden des alten Kratersees hindurch untersucht. 110 Meter ton-sandiger diatomeenführender Sedimente enthalten eine Süsswasserflora die aus 107 Arten und Varietäten besteht ; 5 Formen sind neu und sie werden in di…
Abstract The isotopic exchange of P 32 and Ca 45 with hydroxyapatite was studied along its solubility isotherm. The solution was in a chemical equilibrium with the solid, thus, only isotopic exchange reactions took place in the system. Isotopic dilutions during the exchange process enabled the measurement of a compart…
When a mixture of chloride or sulfate salts of cesium and dysprosium in a 3:1 mole ratio was treated with fluorine gas at 10-60 psig and 200°-350°C, the white Dy(III) starting material was converted to an orange compound with an empirical formula approaching Cs3DyF7. Fluorescence and infrared absorption spectra of flu…
The current drop-weight test methods for evaluating the compatibility of materials with liquid oxygen under impact are briefly discussed, with particular emphasis upon the characteristically poor repeatability of the “threshold value” impact sensitivity ratings yielded by these methods. It is pointed out that this tra…
The assignment of group frequencies in the i.r. spectra of derivatives of aluminium borohydride has been made by the use of aluminium borodeuteride. Variations in the spectra with the change of ligand are discussed. The properties of the compounds in solutions have been studied using 1H n.m.r. spectroscopy, and data o…
Abstract The unit‐cell dimensions of the compounds AB 2 X 5 with A = K, Rb or NH 4 ; B = Pb or Sr and X = Cl or Br have been determined. The alkali strontium chlorides are isostructural with the alkali lead chlorides and bromides.
This investigation shows that below a certain value of the maximum pressure in the region of contact, fatigue cracks are not initiated. This critical value of the maximum pressure is lower the greater the area of contact. In alpha brass the rate of crack initiation increases with increasing values of the maximum press…
The effects of carbide particle sizes and amounts of undissolved carbides in martensite matrix on the fatigue life and other properties have been investigated by using the SUJ 2 kind (JIS) of bearing steel having coarse particle carbides and fine particle ones, respectively, and low chromium steels with different carb…
Paramagnetic susceptibilities have been calculated of ions with formal 2D ground terms perturbed by cubic and axial crystal-fields and spin–orbit coupling. They are critically compared with those computed from a basis set of orbitals restricted to the cubic field 2T2 ground state. Anisotropies are found to be particul…
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