Materials Literature
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A new technique, based on the nuclear activation reaction 15 N(α, n) 18 F, was used to measure nitrogen self‐diffusion coefficients in UN. Temperatures were 1700° to 2000°C and N 2 pressures 7 to 603 torr. The diffusion coefficients were in fair agreement with those obtained by the gaseous exchange method in an indepe…
Optical absorption spectrum measurements and spectral details are presented together with transition assignments and other interpretations for a lemon-yellow gem-quality specimen of iron-rich orthoclase. Only three principal bands--26500, 24000, and 22600 cm (super -1) --are resolved in the spectrum and are tentativel…
New taxa are described as follows: Ralfsia confusa sp. nov., Ralfsia integra sp. nov., Pseudolithoderma nigra sp. nov., Diplura simulans gen. et sp. nov., Endoplura aurea gen. et sp. nov. Lithodermataceae is included in Ralfsiaceae. An emended description of Ralfsia californica is given. Distributional records are als…
A simple homogeneous-field magnetic prism spectrometer is described for use below the camera chamber of a conventional transmission electron microscope. The prism is designed for point-to-point focusing from the exit pupil of the electron microscope to the exit slit of the spectrometer. Energy spectra are scanned by v…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInvestigation of the structure of the pyrosulfite ion in aqueous solution using Raman and infrared spectroscopiesAlbert W. Herlinger and Thomas Veach Long IICite this: Inorg. Chem. 1969, 8, 12, 2661–2665Publication Date (Print):December 1, 1969Publication History Published o…
Abstract Magnesium carbonate powder and granules were compressed and the tablets characterized by their permeability to air and penetration by liquids. To the same materials, magnesium stearate was added, its distribution being varied by varying its concentration, the size of the base material and the method of mixing…
The family of spinel compounds of which CdCr2Se4is the prototype has been found to be simultaneously ferromagnetic and semiconducting. Numerous experiments reveal, moreover, that the electronic states in these materials are strongly coupled to the degree of magnetic order. The interaction between the electronic transp…
Abstract Montmorillonite was found to be the dominant clay mineral in surface horizons of certain soils of the North Carolina Coastal Plain whereas a 2:1–2:2 intergrade clay mineral was dominant in subjacent horizons. In all soils where this clay mineral sequence was found, the surface horizon was low in pH (below 4·5…
Equilibrium sorption, permeation, and sorption kinetic measurements have been made for water in polydimethylsiloxane rubbers containing various amounts of either sodium chloride or silica filler. In general the addition of filler leads to an increase in the uptake of water by the rubber. On the other hand, the permeab…
A single-channel pulse-height analyzer with suitable pulse-shaping circuits designed for partial-discharge measurements is described. The circuit of the pulse-height analyzer has a basic resolution limit of 1.5 μs. The unit may be used in conjunction with an RLC-type partial-discharge-detection circuit and is thus app…
Abstract Differential thermal analysis and electron microscopy of partially molten, extended‐chain polyethylene crystals, grown under elevated pressure, was performed. It could be shown that melting peaks on the low temperature side of the main melting peak are due to narrowly distributed, low molecular weight polymer…
This paper introduces a simple method for objectively analysing the arrangement of beds in sequences of alternating rock types. The number of times that different lithologies overlie one another in a section may be recorded in a table, termed the data array. The probability of one lithology overlying another in a sect…
Iron single crystals with the [100] and [110] axes were extended at 23°C and -78°C and examined by transmission electron microscopy using thin foils cut parallel to lattice planes. In the initial state of deformation, screw dislocations and edge type loops were observed predominantly. Two-dimensional tangles of disloc…
The Cl, Cs, and H nuclear magnetic resonance are used to examine the magnetic structure of antiferromagnetic Cs Mn Cl3·2H2O. The magnetic space group is P2bc′ca′, and the structure consists of eight sublattices with the sublattice magnetization along the b axis. The linear chains invoked by other authors to explain th…
The second paper in this series casts the Boudreaux-Heine method of calculating low-energy electron diffraction (LEED) intensities into a matrix form suitable for extension to complicated surface structures. Calculations are made for the 00 and 01, macron beams reflected from a nickel 111 surface, for norrmal incidenc…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of asymmetric silicon. XV. Stereospecific hydrosilation and exchange reactions of R3SiH(D) catalyzed by Group VIII metal centersLeo H. Sommer, J. E. Lyons, and Hiroshi FujimotoCite this: J. Am. Chem. Soc. 1969, 91, 25, 7051–7061Publication Date (Print):Decemb…
Abstract This is the first paper of a series of reports concerning extended‐chain crystals of flexible, linear high polymers. The general conditions for crystal growth are discussed. Polymer crystallization is described as a two‐step process: nucleation of each crystallizing molecule to a folded‐chain conformation, fo…
Abstract The diffusion studies of several solvents in epoxy polymer reported by Kewi and Zupko in Part I of this series are explained with the solution obtained from the generalized diffusion equation which includes the internal stress contribution. The rate of permeation of a penetrant through a polymer film and the…
A nuclear magnetic resonance survey has been undertaken in order to gain a better insight into the nature of the complex species present in aqueous solutions of the rare-earth ions. Oxygen-17 and proton chemical shifts of water are reported and the effects of concentration and added anions upon them discussed. Nuclear…
1. Kinetic studies of glutamate dehydrogenase were made with wide concentration ranges of the coenzymes NAD(+) and NADP(+) and the substrates glutamate and norvaline. Initial-rate parameters were evaluated. 2. Deviations from Michaelis-Menten behaviour towards higher activity were observed with increasing concentratio…