Materials Literature
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Summary Alkaline microgranites and granite, containing aegirine, riebeckite and astrophyllite, from north-west Pakistan, are briefly described, and tentatively correlated with other alkaline rocks in the region.
Abstract The usefulness of various techniques for characterizing poorlyordered inorganic gel systems in clays is considered. Many established instrumental techniques are unsuitable, but thermal methods, chemical dissolution techniques, and specific surface reactions are more appropriate. The reaction of fluoride with…
Abstract A rate constant is generally derived by using Fick's equation corresponding to the spherical interdiffusion of particles. By using this rate constant, chain and primary radical termination rate constants can be approximated to rate constants for the bimolecular reactions between two radical chain ends, and pr…
Abstract Von der Verbindung La 2 Zr 2 O 7 wurden erstmals Einkristalle dargestellt und röntgenographisch untersucht. La 2 Zr 2 O 7 kristallisiert in der Raumgruppe O Fd3m mit der Gitterkonstanten a = 10,786 Å. Der für die Pyrochlorstruktur charakteristische Sauerstoffparameter hat den Wert x = 0,295.
The diffusion of oxygen in UO 2+α was measured between 600° and 1100°C. Samples with initial O/U values 2.08 and 2.04 were reduced in hydrogen; reduction was monitored continuously by electrical conductivity measurements. The relation between total conductivity and average O/U ratio was derived, and the diffusion coef…
Infrared spectra of undeuterated and partially deuterated NaclO 4 •H 2 O, LiClO 4 •3H 2 O, and Ba(ClO 4 ) 2 •3H 2 O were examined. Crystallographic data point to a weak hydrogen bond between water molecules and the perchlorate ions in LiClO•3H 2 O. This is confirmed by the high HDO stretching frequencies for this comp…
Generalized x-ray scattering factors, in a simplified form, have been applied to several organic molecular crystals. Atomic charge parameters for L-shell scattering factors have been determined from x-ray structure factors by the method of least squares. L-shell scattering factors have been computed for products of SC…
Abstract A new quantitative thermal analysis technique was attempted on ABS and Noryl‐type polyblends. A particular component within a polyblend was identified by its glass transition temperature and the amount of the component was determined from the increase in specific heat at the glass transition temperature. Two…
A theoretical analysis was made of the relaxed plain-knitted structure. The analysis differs from previous ones in that no arbitrary geometrical loop shape is assumed and no empirical methods are used. The loop configuration is de rived from consideration of the reaction forces and couples acting within the structure,…
Trademark of Shell Chemical Co. The material is essentially the diglycidyl
RNA synthesis, one of the early events in spore germination, is underway by the 2nd min. During the first 10 min of germination, RNA synthesis can proceed in the absence of exogenous nutrients at the expense of previously existing RNA. Salvage pathways for bases, nucleosides, and nucleotides are operative during this…
Abstract A pyrolysis–gas chromatographic–mass spectrometric technique for analyzing the pyrolysis products from polymers in an inert atmosphere is described. Initial studies encompassing the pyrolysis of poly(vinyl chloride) homopolymer and a series of PVC plastisols (based on o ‐phthalate esters) have provided a comp…
An electron microscope equipped with conventional electron optics can be used as a `diffractometer' for structure research on individual aperiodic objects. The resolution limit of the electron microscope is not the resolution limit of the `diffractometer' and electron structure research with atomic resolution is possi…
Th e " low te mperature stru cture type" of Ta, O. has bee n found to occur in two di stin c t forms with th e lowes t te mp e rature form hav in g a unit cell 14 tim es th e s ub ce ll a nd an inte rm ed ia ,e te mlJe ra ture form with a unit ce ll 11 tim es the subcell. Th e two t ypes form inte rm ediate partially…
Abstract Poorly crystalline inorganic materials were removed from soil clays of different origin and mineral composition by successive treatments with sodium dithionite, 2 % Na 2 CO 3 and 0·5 N NaOH. Techniques are described whereby difference spectra representing the infrared absorption of the materials removed by th…
1. Mass spectra of the trimethylsilyl derivative and the methyl ester of the N-trifluoroacetyl derivative of bacilysin indicated that the antibiotic had a molecular weight of 270. Several peaks in the spectrum of the methyl ester were consistent with the presence of an N-terminal alanine residue in the molecule. 2. Th…
A theory of cubic-to-tetragonal transformations occurring in spinels containing octahedrally coordinated ($B$ site) ${d}^{9}$ and ${d}^{4}$ transition-metal ions in high concentration is developed. The problem is treated in the spirit of the molecular field approximation. For each Jahn-Teller (JT) susceptible ion in t…
We have found that the lifetime of aluminum films subjected to high current densities at elevated temperatures can be increased by the addition of copper. Previous studies have indicated that the failure mechanism is a combination of electromigration-induced phenomena, including nucleation and growth of voids, which a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSpin label studies of oriented smectic liquid crystals (a model system for bilayer membranes)Joachim SeeligCite this: J. Am. Chem. Soc. 1970, 92, 13, 3881–3887Publication Date (Print):July 1, 1970Publication History Published online1 May 2002Published inissue 1 July 1970http…
Abstract Two octyl-ammonium vermiculite complexes with different 001 periodicities have been studied by i.r. spectroscopy. In each case i.r. spectroscopy affords information on the orientation of the — NH 3 + groups and the strength of the hydrogen bond between these groups and the silicate oxygen surfaces. Also a per…