Materials Literature
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A survey is given of experimental and theoretical studies related to the fundamental properties of single crystal vanadium oxides. Emphasis is put on the relationship which exists between V2O5 and the lower oxides, mainly V4O9 and V6O13. Special attention is paid to the role played by the vanadyl—oxygen vacancy, both…
X-ray diffraction investigations of both nematic and smectic phases of a number of compounds containing cyano end groups have revealed several of them to have a novel structure. This consists of two coexisting mass density fluctuations (heavily damped for the nematics) with incommensurate wavelengths corresponding, re…
Substitutional nitrogen donors in single-crystal silicon have been produced by pulsed ruby-laser annealing of amorphous silicon created by 4\ifmmode\times\else\texttimes\fi{}${10}^{15}$ 160-keV (0.995 $^{28}\mathrm{Si}^{+}$ + 0.005 $^{14}\mathrm{N}_{2}^{+}$)/${\mathrm{cm}}^{2}$. EPR measurements indicate that these is…
Mechanical properties and peculiarities of fracture surfaces of four dispersion strengthened alloys (Mo1, Nb1, Mo2, and Vl) are investigated in tension in the temperature range from −196 to 1600 °C with a strain rate of 10−3 s−1. At the choice of alloys for investigation two main parameters are taken into account: mat…
The 365 nm emission band observed at 100, 165, 205, 260, and 325 K in the thermoluminescence of undoped zircons, synthesized with the hydrothermal method, and which are X-irradiated at 77 K, is attributed to the SiO lattice groups. It is established that a paramagnetic trap centre is associated to most TL peaks. These…
A new class of layered materials has been prepared by alternate deposition of two dissimilar metals. Strong experimental evidence is shown that coherent structures with layer thicknesses approaching interatomic spacing can be prepared in this fashion. The experimental x-ray measurements are found to be in good qualita…
A highly precise method for locating the valence-band edge in x-ray photoemission spectra is reported. The application to measuring semiconductor interface potentials is discussed. X-ray photoemission-spectroscopy experiments on Ge and GaAs(110) crystals have given Ge $3d$, Ga $3d$, and As $3d$ core level to valence-b…
In standard multiconfigurational Hartree–Fock (MCSCF) theory, a two electron integral transformation is performed before application of the equation defining the MCSCF approach in each iterative cycle. It is shown how the two electron integral transformation may be replaced by an approximate orbital transformation int…
Molecular models are constructed for large structural units appropriate to ${\mathrm{As}}_{x}{\mathrm{S}}_{1\ensuremath{-}x}({\mathrm{Se}}_{1\ensuremath{-}x})$ glasses near $x=0.4$. The models are similar to those previously constructed for ${\mathrm{Ge}}_{y}{\mathrm{S}}_{1\ensuremath{-}y}({\mathrm{Se}}_{1\ensuremath{…
The average moments and the moment disturbances of ferromagnetic Ni-Pt alloys with concentrations of 20, 30, 40, 50, 55, and 57 at.% Pt have been measured by the magnetic diffuse scattering of neutrons. The data have been analyzed with the linear superposition model of Marshall including short-range order. The data ha…
Colloidal solutions of amorphous V2O5 are used for preparing semiconducting layers. Reasons for the high measured conductivity (σ≃0.8–1.0 Ω−1 cm−1) are discussed. The temperature dependence of σ is analyzed in terms of a temperature-dependent activation-energy model based upon the assumption of a random distribution o…
Luminescent molecules near metal surfaces can have dramatically decreased quantum efficiencies and lifetimes. For example, decreases of \ensuremath{\sim}${10}^{3}$ in quantum efficiency and in lifetime occur for nitrogen atoms within 3 nm of potassium surfaces. This paper presents experimental decay curves for light e…
The problem of experimental evaluation of the complex stress intensity factors K at the apices of sharp V-notches in homogeneous, isotropic and elastic plates, symmetrically loaded in their planes, is treated by applying the experimental method of reflected caustics. The symmetry in loading and in position of the notc…
Molluscan bivalve hinge ligaments are composed of long needle-shaped aragonite crystals embedded in a protein matrix. These crystals are twinned and, in general, the twin forms a thin lamella through the center of the crystal.
Abstract Frank first became interested in dislocations through reading Taylor’s 1934 paper. He wrote to Taylor, pointing out that his model was two-dimensional, and asking if a dislocation had to be a straight line. This letter was not answered, and Frank did not think further about dislocations until he came to Brist…
According to a study carried out by Arthur D. Little, a leading firm of consultants, demand for semiconductors is expected to grow by an average of 20 per cent a year up to 1983. The report points out that the growth in sales will be due to increases in demand for electronics equipment and a marked fall in the price o…
Abstract In eutektischer Kalium‐Natriumnitratschmelze wurden stationäre Stromspannungskurven an Stahl St 37 aufgenommen. In Gegenwart von Natriumchlorid in Konzentrationen über 0,035 Mol/kg wurde Lochfraß an den passiven Stahlelektroden beobachtet. Er folgt einem kubischen Zeitgesetz.
Abstract Equations describing the sorption kinetics of asymmertric membranes composed of AB and ABC laminate slabs in finite and in semi‐infinite well‐stirred baths are presented, and some properties of these systems are discussed.
The morphology and elemental analyses of calcification occurring in Bacterionema matruchotii were studied by analytical electron microscopy. Early electron densities were found associated with metachromatic granules and cell membranes. Amorphous calcium phosphate appeared before apatite was detected.
Klebelsbergite is verified as a valid mineral species, in museum specimens from the type locality, Baia Sprie (Felscib6nya), Rumania. Klebelsbergite occurs as pale yellow to orange-yellow crystals radially grown on stibnite. Wet-chemical analysis of synthetic klebelsbergite, supported by electron microprobe analyses o…