Materials Literature
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Abstract The heat capacity of single crystals of magnesium oxide has been measured in the temperature range 3 to 270°K with estimated accuracies of ± 0.5% for 10 < T < 20°K and ± 0.2% for T > 20°K. Reliable results were not obtained below 10°K because of desorption of helium exchange gas in the ca…
A formula for the total cross section for elastic scattering of fast electrons by a Thomas-Fermi potential, including relativistic effects, is derived from the differential cross section previously obtained.
Transparent single crystals of W${\mathrm{O}}_{3}$, in the form of plates as large as 10 mm\ifmmode\times\else\texttimes\fi{}10 mm, have been prepared by a sublimation method. The domain structure of these crystals was investigated from room temperature to 1350\ifmmode^\circ\else\textdegree\fi{}C, and a new and peculi…
A modified Chaulnes' method using polarized light has been developed to measure the indices of refraction of W${\mathrm{O}}_{3}$. By this method, the three principal indices of refraction of a crystal were obtained by observations in the direction of only one optic principal axis. For W${\mathrm{O}}_{3}$, the mean val…
The polarization of fluorescenoe in hexagonal (wurtzite) crystals of CdS and ZnS gives a clue to the symmetry of the states between which the luminescent transition occurred. Unfortunately this clue is at present equivocal: there are many models for the center which would be consistent with the observed polarization.…
A phenomenological model is developed to facilitate calculation of lattice thermal conductivities at low temperatures. It is assumed that the phonon scattering processes can be represented by frequency-dependent relaxation times. Isotropy and absence of dispersion in the crystal vibration spectrum are assumed. No dist…
Abstract Die katalytische Dehydrierung gasförmiger Ameisensäure wird an Nickel‐, Kobalt‐ und Silber‐Filmen, die auf Al 2 O 3 ‐Träger aufgedampft sind, untersucht. Die n‐Leitung der Al 2 O 3 ‐Träger ist durch Dotierung erhöht oder vermindert. Die für die Ameisensäure‐Dehydrierung am Metall erforderliche Aktivierungsene…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSonically Induced Heterolytic Cleavage of Polymethylsiloxane.J. R. Thomas and L. deVriesCite this: J. Phys. Chem. 1959, 63, 2, 253–256Publication Date (Print):February 1, 1959Publication History Published online1 May 2002Published inissue 1 February 1959https://pubs.acs.org/…
Equipment and procedure are described for applying thin films of titanium and zirconium as tritium carriers to backings of copper, gold and platinum. A large proportion of the coatings prepared absorbed high atom ratios of tritium, titanium being more satisfactory in this respect than zirconium. It is suggested that d…
A method is described for producing durable two-layer anti-reflexion coatings on low refractive index (approximately 1.5) glasses. Practical difficulties in evaporating absorption free films of high index materials are avoided by reactively sputtering a bismuth oxide film which is then coated with an evaporated magnes…
As a continuation of an earlier work, SrS phosphors, singly activated with rare-earth ions have been excited with uv irradiation, at 77°K. The resultant visible fluorescent emissions have been measured and correlated with crystal field splittings of energy levels. Energy level diagrams are presented with possible term…
A brief review of investigations relating fiber structure to mechanical properties of cotton is given. The relationship of fibril alignment, as measured by the x-ray technique, to the strength and elongation properties of cottons covering a wide range in physical properties is discussed. Alteration of mechanical prope…
Mass attenuation coefficients have been measured for aluminum and copper in the energy range of 6 kev to 40 kev and for chromium, cobalt, nickel, and zinc in the energy range of 6 kev to 14 kev. The average most probable error is less than 3% and the agreement with theory is good.
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSome New Sulfur-bearing Fluorocarbon Derivatives1,2Richard D. Dresdner and John A. YoungCite this: J. Am. Chem. Soc. 1959, 81, 3, 574–577Publication Date (Print):February 1, 1959Publication History Published online1 May 2002Published inissue 1 February 1959https://pubs.acs.o…
Die Atom- und Elektronenwärme des Molybdäns und Wolframs wird zwischen 10°K und 273°K an zwei kompakten Versuchskörpern gemessen, die eine Reinheit von 99,99% aufweisen. Die neueren Angaben verschiedener Beobachter stimmen gut untereinander überein. Die Standardentropien für 25°C ergeben sich zu 6,83 Clausius für Moly…
The room temperature yield end fracture stresses have been measured for a series of high-purity polycrystalline molybdenum tensile specimens with grain diameters varying from 0.03 mm to 0.26 mm. The yield stress results can be fitted to Petch's relation [sgrave]Y =[sgrave]I+kYl−1/2 with [sgrave]I= = 11.00 kg mm−l and…
Recent lifting of the security restrictions now permits publication of measurements of various effects of pressure on plutonium made during the war. Compressions on the alpha phase were measured at room temperature to 40 000 kg/cm2 in one apparatus and to 100 000 in another. The total volume compression under 100 000…
A systematic experimental study has been made of the effect of adding small amounts of gold to copper on the dislocation damping in copper measured at 37 kc in longitudinal resonance. The results have been classified in terms of the dependence of the damping on strain amplitude and time with temperature and compositio…
Abstract The effects of pH and concentration on foam separation of the protein bovine serum albumin (BSA) from solution has been studied. All results agree, at least qualitatively, with theory. BSA maximum enrichments were observed at the isoelectric pH and enrichment ratio was found to increase with decreasing protei…
Abstract On the basis of our experimental data and a detailed kinetic analysis, the following mechanism of hydrogen ion catalysis is proposed for polyesterification as well as for the simple esterification reactions: magnified image The kinetic equation in terms of [COOH] (= C ) is where C 0 = [COOH] and r = [COOH]/[O…