Materials Literature
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The high-field electrical properties of several groups of transition-metal phosphate glasses have been examined, especially those based on V, Fe, Cu and Mo ions, and pure and doped tungstates. Conductivity measurements have been carried out under DC and pulse conditions at fields up to approximately 10 6 V cm -1 but b…
Photoemission energy distributions for $20<~h\ensuremath{\nu}<~50$eV for semiconducting Fe${\mathrm{S}}_{2}$ (fool's gold) show a narrow, \ensuremath{\sim}1 eV wide, localized uppermost valence level, whereas the corresponding levels of semiconducting Ni${\mathrm{S}}_{2}$ are broad (\ensuremath{\sim}3.5 eV) and…
The structure of the hexamethylenetetramine 14N nuclear quadrupole resonance line has been studied in detail on a powdered sample at 77°K. An improved, frequency-stabilized spectrometer, interfaced to a digital computer, was used in resolving fine details of the experimental lineshape. The line shape could be fitted b…
The complete ligand-field, Coulomb interelectronic repulsion, and spin-orbit interaction matrices have been derived for the d 5 electron configuration within octahedral (O h ) and tetrahedral (T d ) symmetry. The calculations were performed in both the weak-field and strong-field coupling schemes and complete agreemen…
The electron beam retarding potential technique was used in a display-type Varian LEED-Auger apparatus to determine work function changes on contact materials Pd, Au, Ag and Pd-Ag 40 at.% (atomic percent). Surface compositional changes were created by heating and argon ion bombardment treatments and monitored by Auger…
Iron glaebules occur extensively in tropical and subtropical soils, therefore, glaebules were collected from a plinthic soil (Plinthic Paleudults) of the Southern Coastal Plain of the United States for classification and to determine their chemical and mineral composition. Glaebules were classified into four categorie…
Summary Vincentite, a new palladium mineral containing As, Sb, and Te, has been discovered in platinum-gold concentrates from the Riam Kanan River, SE. Borneo. It occurs as small grains (up to 40 µm) in iron-bearing platinum. In reflected light, vincentite is light brownish-grey and in some sections weakly anisotropic…
A simplified kinetic model describing the mechanism of pilling is proposed. This model involves only three parameters, which relate to the main stages of the process: the total number of pills, the rate of pill formation, and the rate of pill wear-off. These parameters can easily be calculated from the pill curve of t…
Abstract The thermal decomposition of [Ni(N2H4)6]X2 (X=Cl, Br, I) in solid phase was investigated by means of derivatography and IR spectral measurement. It was found from the derivatography that the decomposition of the chloride and bromide proceeded via tris-, bis-, and mono-hydrazine complexes as metastable reactio…
This paper considers the physical processes which may occur when a liquid weld metal drop comes in contact with a liquid metal pool. Experiments with drops of aqueous KCl solutions and mercury, combined with a theoretical analysis of the effects of surface tension and Lorentz forces, lead to the following conclusions.…
A torsion-balance apparatus, incorporating a photopotentiometer device and developed to study the torsional-hysteresis and torque-relaxation behaviour of both monofilament and multifilament yarns under conditions of constant tension, is described. Differences in the shape of the torsional-hysteresis curves are studied…
The rate of degradation by ultrasonation of polystyrene in tetrahydrofuran solutions has been measured at various concentrations, temperatures, and irradiation intensities. As reported earlier, the course of the changes in molecular weight distributions is independent of the molecular weight (MW) of the initial polyme…
The thermoluminescence of SrSO 4 and BaSO 4 doped with dysprosium and thulium was studied. The phosphors were crystallized from H 2 SO 4 solution by evaporation. SrSO 4 :Dy and SrSO 4 :Tm exhibit the same glow curve, both having a major glow peak at 140 degrees C. BaSO 4 :Dy and BaSO 4 :Tm also exhibit identical glow…
Abstract Crystalline hydrated double carbonates of rare-earth elements and sodium were obtained by adding sodium carbonate solutions to rare-earth chloride solutions. The formula of the precipitates was determined to be LnNa(CO3)2·6H2O (Ln=La, Ce, Nd, Sm, Gd, Dy, and Y). The products have similar X-ray powder diffract…
Atactic polystyrene was subjected to an elevated pressure–temperature cycle with the resulting densification, mechanical properties, and thermal scanning behavior observed. Most densifications were carried out with the PST as a viscous liquid. In this manner, ambient residual compactions greater than 2% were produced.…
The optical absorption spectra of colloidal solutions of Cu with gelatin as a stabilizer are studied. One characteristic absorption peak is found at 2.14 eV (580 nm) which is attributed to surface plasmons of Cu particles. This result agrees with previous measurements of energy loss of electrons transmitted through th…
The feasibility of two-dimensional numerical analysis of the split-Hopkinson pressure bar experiment is proven. A general elastic-plastic artificial viscosity computer program is shown to give an adequate solution for two-dimensional elastic response of a pressure bar subjected to a Heaviside step loading in time whic…
An opti cal and electron microsco pi cal study is PJese nte d of th e habits exhibited by chainfolded polyoxymethylene crys tals grow n from hot 0.02 percent solutions of th e polymer in orthodi chlorobe nzene when th ese solutions are cooled to temperatures (Te) between 140 and 80 C inclus ive . In co ntras t with th…
A transmission and scanning electron microscope study was made of cell wall development in the root velamen of Ansellia gigantea. The pattern of fibrillar deposition in the primary walls was established by means of shadowed surface preparations. The helical wall thickenings were shown to originate by the localised app…
Summary Experimental procedures giving complete unimolecular surface coverage of montmorillonite by ethylene glycol (EG) are described. The EG sorption data, excluding rate effects, are independent of the nature of the exchangeable cations associated with the clay surfaces. The amount of EG sorbed (0.357±0.007 g EG/g…