Materials Literature
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A useful and significant relationship exists between the Debye temperature θD and the monovacancy formation energy E f. It appears that E f for close-packed metals can be calculated from θD with an uncertainty of not more than 5–10%.
The diffusion cross section for electrons in a gas of polar molecules is calculated. The improvement over a previous calculation is the use of the exact scattering cross section of a charged particle by a point dipole rather than the first Born approximation. For ${\mathrm{H}}_{2}$O the correction amounts to about 20%…
Temperature and bias characteristics of ceramics of Pb(Zr-Ti)O 3 and its families have been measured. Bias dependence can be understood with a schematic model on the reorientations of 180° and 90° domains. Dielectric and elastic anisotropies of the single crystal are expected to be larger in the rhombohedral phase tha…
The derivation is outlined of a general relation connecting the macroscopic plastic strain rate with the configuration and velocity distribution of dislocations in a monocrystal with a single active glide system. This can be simplified for particular cases, the most simple being the case of parallel straight dislocati…
Twinned crystals of low cristobalite from Ellora, Hyderabad, India were found to have space group P4121 (or P4321) and cell dimensions a = 4.978 and c = 6.948 A. A three-dimensional full-matrix least-squares refinement based upon 110 integrated intensities which were corrected for the effects of twinning, confirmed NI…
The magnetocaloric effect and magnetization of a polycrystalline ellipsoid of dysprosium were measured in magnetic fields up to 20 kOe from the temperature of liquid nitrogen to room temperature. Dysprosium exhibits both heating and cooling upon adiabatic magnetization depending on its magnetic state (ferromagnetic, p…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTChemical and Structural Studies of Rhenium(V) Oxyhalide Complexes. I. Complexes from Rhenium(III) BromideF. A. Cotton and S. J. LippardCite this: Inorg. Chem. 1965, 4, 11, 1621–1629Publication Date (Print):November 1, 1965Publication History Published online1 May 2002Publish…
A study has been made of the behaviour of {1012} ⟨011⟩ type deformation twins in fatigued cadmium, zinc, magnesium and titanium. Plastic deformation is accentuated at twin interfaces, which subsequently become serrated : the serrations are accommodated by closely spaced kink boundaries. Pre-existing twins are broken u…
The general arrangement of cytoplasmic organelles in Amphipleura pellucida Kutz. is similar to that in other naviculoid diatoms. The chromatophores are parietal with a single, non‐membrane‐limited, pyrenoid. The pyrenoid is crossed by several double‐disc lamellar bands which are occasionally interrupted by less dense…
The effect of pre-existing micro-cracks on the fracture of [010] tungsten single crysta's has been investigated. Cleavage cracks on (010) planes were introduced into the edge of the specimens by a spark-machining technique. Tensile tests at 77°K showed that the fracture stress was dependent on the crack length accordi…
The reversible dimerization of the anion radical of 7,7,8,8-tetracyanoquinodimethane in aqueous solution has been studied spectroscopically. Analysis of the spectra yields an equilibrium constant for dimerization (2A−⇆A2=) at 25° of 2.5×103 liter/mole and a heat of dimerization of −10.4 kcal/mole dimer.
Quantitative X‐ray diffraction methods were used to define the kinetics of spinel formation. Diffusion controlled reaction rate constants were calculated on the basis of the reaction models of Jander, Dunwald‐Wagner, Valensi, Zhuravlev et al. , Ginstling‐Brounshte'n, and Kroger‐Ziegler. The model proposed by Valensi i…
Composition and protectiveness of the iron sulfide film, formed as a result of the liquid phase H2S-CO2-H2O corrosion of Armco iron, have been related to the initial pH of the solution. Composition of the film was determined by electron diffraction analysis. Protectiveness of the film was determined by measuring the w…
Kominek, Leo A. (University of Illinois, Urbana), and H. Orin Halvorson. Metabolism of poly-beta-hydroxybutyrate and acetoin in Bacillus cereus. J. Bacteriol. 90:1251-1259. 1965.-The synthesis of poly-beta-hydroxybutyrate (PHB) in Bacillus cereus strain T begins after the cessation of logarithmic growth. Its accumulat…
Tris-sarcosine calcium chloride, (CH 3 NHCH 2 COOH) 3 ·CaCl 2 , is ferroelectric below the Curie point, 127°K, where the dielectric constant, ε b , at low frequencies shows a sharp peak. The dielectric constants ε a and ε c . do not show any noticeable anomaly at the Curie point. The dielectric measurement at a microw…
The crystal structure of porphine, the parent compound in the porphyrin series, was determined by x-ray diffraction analysis. The phases of the normalized structure factors were obtained by the probability methods of Hauptman and Karle. The crystals are monoclinic with four molecules per unit cell, and the C2h5—P21/a…
Abstract Use of reinforcing fillers in elastomers ranks as one of the two most important processes in rubber technology—only vulcanization can be considered to surpass it in its universal application. From the time of the earliest observations that certain pigments are capable of imparting reinforcement to natural rub…
Mie scattering calculation to support theory that interstellar extinction is caused by graphite particles
The Rosseland mean due to Compton scattering at temperatures ranging from kT = 0.01mc2 to kT = 0.35mc2 and for densities ranging from p = 10 gm/cm2 to p = 106 gm/cm2 is calculated. In most of this semidegenerate region, Compton scattering dominates over electron conduction, bound-free transitions and free-free transit…
The energy of an extended dislocation is decreased if the energy of the stacking fault formed between its component partial dislocations is reduced. It is suggested that such an effect may influence the yield stress of an alloy containing coherent precipitates of lower stacking-fault energy than the matrix. The propos…