Materials Literature
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The characteristic energy loss spectrum of solids is analyzed with the aid of the dielectric formulation of the many-body problem developed by the authors. It is shown that a measurement of the angular distribution of inelastically scattered fast electrons is a direct measurement of the imaginary part of the inverse d…
Abstract The primary objective of this investigation has been to explain why cellulose acetate behaves as a semipermeable membrane in saline water. To explain this phenomenon, two different mechanisms for the transfer to water and ions through cellulose acetate membranes were formulated. Those ions and molecules that…
Abstract The definitions given previously for work-hardening and perfect plasticity are broadened to cover viscous effects. As before, the system considered is isothermal and includes both the body and the time-dependent set of forces acting upon it. An external agency is supposed to apply an additional set of forces…
The resistance offered to the flow of heat by the mismatch of the elastic constants at the interface between two materials has been calculated. It is shown that for a perfectly joined interface the heat flow is proportional to the difference of the fourth powers of the temperature on each side of the interface. Deviat…
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…