Materials Literature
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Fluorescence, excitation, and pulsed fluorescence measurements have been made on a single crystal of CaWO4 over a wide temperature range. The temperature dependences of the integrated fluorescence intensities and lifetimes were obtained for different excitation wavelengths. A sharp increase in the fluorescence lifetim…
The nature of the defects produced in noncrystalline SiO2 and α-quartz single crystals by fast neutron irradiation (E > 0.18 MeV) has been investigated by Raman and infrared spectroscopy, small-angle x-ray scattering, and electron microscopy. Measurements were made at 25°C on samples irradiated to integrated fl…
The anisotropy of the translational self-diffusion tensor in the smectic-$A$ ($\frac{〈{D}_{\ensuremath{\parallel}}〉}{〈{D}_{\ensuremath{\perp}}〉}=0.3$) and smectic-$C$ phases of terephthal-bis-4-$n$-butylaniline has been determined by multipulse NMR. The experimental results are interpreted in terms of a pseudolattice…
The growth rate of anorthite crystals from the melt is studied as a function of temperature with undercooling in the ranges 52-152 and 402-652 degrees C. The triclinic form is invariably observed as the crystallization product, growth is preferentially in the c direction, and the interface morphology is faceted. Signi…
The V 0 centre in magnesium oxide consists of two holes trapped by a magnesium vacancy. The hyperfine spectrum due to interactions between this S=1 spin system and two equivalent neighbouring 25 Mg axial nuclei has been observed and values for the isotropic and anisotropic hyperfine parameters and the nuclear quadrupo…
The unusual ferroelectric, magnetic, dynamical and structural properties exhibited by the boracites have attracted increasing attention over recent years. Also of recent interest has been the nature of phase transitions involving more than one order parameter. Boracites are believed to afford examples of such transiti…
We have applied a recently developed method for sensitive calorimetric measurements to investigate the nematic---smectic-$A$ phase transition in pure N-$p$-cyanobenzylidene-$p\ensuremath{-}n$-octyloxyaniline. The results indicate a very weak first-order transition with a transition entropy of $(0.017\ifmmode\pm\else\t…
The thermal conductivity of a borosilicate glass has been measured in the temperature range 0.05-50 K. The samples contained well-defined holes to provide a source of phonon scattering. The results are consistent with the predictions of the Debye model using experimentally measured sound velocities. The results also i…
Article Verfeinerung der Kristallstruktur von Samsonit, ( SbS3)2Ag2IIIAg2IVMnVI was published on November 1, 1974 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 140, issue 1-2).
(1974). Khibinskite, K2ZrSi2O7, a new mineral. International Geology Review: Vol. 16, No. 11, pp. 1220-1226.
Article Dynamische Kernpolarisation und zwischenmolekulare Wechselwirkungen in phosphor- und thalliumorganischen Lösungen was published on November 1, 1974 in the journal Zeitschrift für Physikalische Chemie (volume 93, issue 1-6).
Serendibite with very similar analyses is known from Ceylon and New York. The triclinic cell of symmetry P[unk] and volume 670.9 A(3) contains 2Ca(1.64)Mg(2.64)Fe(0.27) (II)Al(4.64)B(1.66)Si(3)O(20), with 14 metal atoms and 20 oxygen atoms in the asymmetric unit. It was solved by the "direct" method of transforming th…
Abstract The kinetics of isothermal crystallization of polyethylene under high pressures ranging from 840 to 5300 kg/cm 2 has been studied dilatometrically. The crystallization rate estimated from the half‐time of the overall transformation increases markedly with pressure. The Avrami exponent n becomes smaller with i…
Abstract Das Gleichgewicht PbCl 2,g + ThCl 4,g = PbThCl 6,g wurde mit der Knudsen‐Methode massenspektroskopisch gemessen. Mit Einführung von ΔS°(298) = −36 cl und °Cp = 4 cal/°, Mol ergibt sich ΔH°(298) = −32,0 kcal/Mol. Ferner wurden die Sättigungsdrucke über PbCl 2,f und ThCl 4,f gemessen und mit Literaturangaben in…
Article A redetermination of the crystal structure of cosalite, Pb2Bi2S5 was published on November 1, 1974 in the journal Zeitschrift für Kristallographie - Crystalline Materials (volume 140, issue 1-2).
The pressure dependence of the superconducting transition temperature for the layer compounds h-Nb 1+x Se 2 (x=0, 0.01, 0.02, 0.05 and 0.1) and 4H-NbSe 2 has been investigated to 25 kbar. A strong enhancement of T c is observed. A brief discussion of the influence of pressure upon the band structure and its relationsh…
Abstract The intrinsic viscosities of low molecular weight fractions of atactic poly(acrylic acid) at 50% and 100% neutralization and at several concentrations of added sodium chloride is studied. In salt‐free solutions the 100% neutralized polymer assumes the rigid rod form. The results at concentrations of sodium ch…
A staple draftometer is described using a "Hall Effect" wattmeter as the transducer for measuring dynamic forces in staple slivers during drafting. The procedure for calibration and use of the instrument is also given. A novel feature of the apparatus is the use of a decade resistance box to calibrate the desired full…
A series of 30 runs were performed to gain information on the fragmentation of molten UO2when dropped into a bath of liquid sodium. In this experiment, hollow cylindrical UO2 pellets were heated with electric current fed to a tungsten rod, passed through to center hole. The resulting molten UO2 dripped down its fall i…
Abstract Die röntgenographische Einkristall‐Strukturuntersuchung zeigt, daß Ba 2 CuTeO 6 bei Zimmertemperatur in einer triklinen JAHN‐TELLER‐Variante des hexagonalen Ba 2 NiTeO 6 ‐Typs (12‐Schichten‐Struktur) kristallisiert: equation image Gruppierungen aus drei flächenverknüpften Oktaedern sind über ausschließlich ec…