Materials Literature
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Abstract The ultimate tensile strength and modulus of elasticity of individual osteons from human and ox compact bone were determined with a specially designed microwave extensimeter. The results were related to the degree of calcification and the orientation of collagen fiber‐bundles in successive lamellae of the ost…
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Abstract Durch Pyrolyse kohlenstoff‐haltiger Gase bei rd. 2000°C und Abscheidung des dabei anfallenden elementaren Kohlenstoffs auf einem glatten Substrat erhält man einen Graphit', der einen hohen kristallographischen Orientierungsgrad besitzt und dessen physikalische Eigenschaften zum Teil stark richtungsabhängig si…
Abstract When cracks of any size spread in brittle materials and when large cracks spread in large structures of ductile materials, irreversible deformation is confined to a small volume of material contiguous with the crack surfaces. A general theory of quasi-static crack propagation under such conditions is formulat…
Abstract Single crystals of iron were deformed in tension at an impact strain rate of about 1000 per second at temperatures between 20 and -196 °C. The results were compared with those of tests at a conventional rate of strain. The effect of raising the strain rate was to increase the yield stress, to increase the tem…
The crystal structure of the solid electrolyte RbAg(4)I(5) has been determined from single-crystal x-ray diffraction counter data. There are four RbAg(4)I(5) in a cubic unit cell with a = 11.24 A. The structure refinement, by least squares, is based on space group P4(1)3 (O(7)). The arrangement of the iodide ions is s…
A model of two-dimensional hydrogen-bonded crystals satisfying the ice rule is presented and solved exactly in the presence of an external electric field. The transfer-matrix method is used. The model includes, for special values of the parameters, the ice problem, the Rys $F$ model of an antiferroelectric, and the Sl…
The Slater KDP model is solved for all temperatures and with an electric field. Above ${T}_{c}$ the specific heat behaves like ${(T\ensuremath{-}{T}_{c})}^{\ensuremath{-}\frac{1}{2}}$ and the polarizability like ${(T\ensuremath{-}{T}_{c})}^{\ensuremath{-}1}$. There is a first-order phase transition at ${T}_{c}$ (laten…
The crystal structures at 298°K of MnBr2·2H2O and CoBr2·2H2O have been refined by full-matrix least-squares methods using three-dimensional MoKα intensity data. In these compounds, polymeric chains of metal and bromine atoms arranged in a near-square planar arrangement with each bromine atom shared by two metal atoms…
The Mössbauer absorption spectrum of 57Fe in single crystals of Na2[Fe(II)(CN)5NO]·2H2O has been studied. The angular variation of the ratio of intensities of the quadrupole-splitted lines with the incident radiation has been measured at different crystal orientations. The results may be satisfactorily interpreted by…
Phonon resonances have been observed in both KCl:Li and KBr:Li through measurements of the low-temperature thermal conductivity between 0.05 and 100\ifmmode^\circ\else\textdegree\fi{}K. Their frequencies are 1.2 and 63 ${\mathrm{cm}}^{\ensuremath{-}1}$ in KCl, and 3.2 and 39 ${\mathrm{cm}}^{\ensuremath{-}1}$ in KBr. S…
The rate of vibrational deactivation by collision of polyatomic molecules is discussed. Previous calculations for CO2 by the author are corrected. A systematic method to find the steric factor in complex collisions is proposed, and the best procedure for evaluation of such collisions is discussed. Mixture of vibration…
Well-resolved high-resolution proton nuclear resonance spectra have been observed for solutions of Co(II) poly(1-pyrazolyl) borate chelate systems in CDCl3. In a previous paper [J. P. Jesson, J. Chem. Phys. 45, 1049 (1966)], optical and paramagnetic resonance data have been described for some of these compounds. The c…
Phase relations among Cs II, Cs III, Cs IV, and liquid have been determined by resistance and differential-thermal-analysis techniques. The triple-point coordinates among Cs II-III-liquid and Cs III-IV-liquid are (42.5 kbar, 88\ifmmode^\circ\else\textdegree\fi{}C) and (43.9 kbar, 98\ifmmode^\circ\else\textdegree\fi{}C…
Self-quenching of Nd emission from Nd4F3/2 in the Na0.5(Y, Nd)0.5WO4 tungstates (scheelite structure) and transfer from Nd4F3/2 to Tb or Eu involves dipole—dipole interactions. Self-quenching of Nd is largely by thermally activated interactions at 295°K. However, processes requiring the simultaneous transfer of ∼600 c…
The intrinsic switching path for the electric field enforced transition from antiferroelectric to ferroelectric states has been computed for the simple Kittel linear antiferroelectric. The generalized switching curves give values of the polarization, free energy, and dielectric susceptibility as a function of applied…
A detailed study has been made of the EPR spectra of trapped hole centers formed by x irradiation in alkali silicate glasses. The spectra of the five alkali silicate glasses were studied as a function of composition, microwave power, and bleaching temperature. It was found that the spectra could be decomposed into two…
The energy-dependent rate for inelastic scattering of electrons by production of electron-hole pairs is computed by first-order perturbation theory for silicon using a screened Coulomb interaction with a frequency- and momentum-dependent dielectric function calculated for silicon in the random-phase approximation. The…
The fluorescence of Y3Al5O12–Ce3+ under cathode-ray excitation consists of an emission band peaking at 550 nm. The decay time is 0.07–0.08 μsec. In view of these properties this phosphor is very suitable for flying-spot cathoderay tubes for color television.
Abstract In the preceding paper Frank & Lawn (1967) investigated theoretically the development of a cone crack in the strongly inhomogeneous Hertzian stress field. The analysis outlined in that paper is now extended to incorporate a sliding motion of the spherical indenter across the specimen surface, assuming a u…