Materials Literature
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An exploratory study of the effects of compositional variation on glass formation in low‐silica aluminate compositions revealed that CaO is essential for glass formation at ordinary quenching rates. Other oxides, such as Li 2 O, MgO, BaO, ZnO, Na 2 O, K 2 O, BeO, B 2 O 3 , and PbO, can be present in the glass in limit…
The adiabatic elastic moduli of single-crystal Zr vary linearly with hydrostatic pressures up to 4.7 kbar. The pressure derivatives are dC11/dP=3.93, dC33/dP=5.49, dC44/dP=−0.22, dC66/dP=0.26, dC12/dP=3.42, and dC13/dP=4.25. The average high-temperature Gruneisen mode γ̄H calculated from this data is in wide disagreem…
Surf-zone diatom populations occurring along the west coast of the Olympic Peninsula, State of Washington, are quite comparable to similar surf-zone populations along the west coast of North Island, New Zealand. In both locations, Chaetoceros armatum T. West contributes the predominant biomass. Asterionella glacialis…
A statistical mechanical model of gas solubility in glass is presented. For equilibrium, the Gibbs free energy of the free gas is equated to that of the gas in solution. Expressions for the Gibbs energies are obtained from assumptions of the atomic motion in the free gas and dissolved states. The resulting solubility…
Abstract A palmityl thioesterase II which is insensitive to inhibition by diisopropyl fluorophosphate has been purified 20-fold from extracts of Escherichia coli. This enzyme exhibits properties which distinguish it from the more substratespecific diisopropyl fluorophosphate-sensitive palmityl thioesterase I known als…
The magnetic properties of the hexagonal intermetallic compounds involving the rare-earth and3dtransition metals have been reported in the literature. These alloys look promising as fine-particle permanent magnets. A large number of samples in the system SmCo5-xCuxwere prepared by induction melting under a protective…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTVibrational and pure nuclear quadrupole resonance spectra of hexahalometalatesTheodore Lawrence Brown, W. Gordon McDugle Jr., and L. Gregory KentCite this: J. Am. Chem. Soc. 1970, 92, 12, 3645–3653Publication Date (Print):June 1, 1970Publication History Published online1 May…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTNuclear magnetic resonance spectra and the electronic spectra of some silicon and germanium phthalocyaninesAlexander R. Kane, John F. Sullivan, David H. Kenny, and Malcolm E. KenneyCite this: Inorg. Chem. 1970, 9, 6, 1445–1448Publication Date (Print):June 1, 1970Publication…
Morphological, x-ray crystallographic and x-ray topographic studies on many specimens grown in this laboratory lead to a consistent description of polytypism in vapour-phase grown ZnS. Crystal growth begins with the emerging of hexagonal 2H needles from the polycrystalline substrate. The needles thicken during the gro…
Bis-(4′-n-alkoxybenzal)-2-chloro-1, 4-phenylenediamines and bis- (4′-n-alkoxybenzal)-2-methyl-1, 4-phenylenediamines with different alkoxy groups have been synthesized. Similar compounds with fluoro, bromo and chloro groups replacing the alkoxy groups have also been prepared. All the compounds show a nematic liquid ph…
The crystal dynamics of sodium nitrite has been studied by coherent neutron inelastic scattering techniques. The normal modes of vibration propagating along the three principal symmetry axes in the crystal at 296°K have been measured. The results have been used to find the parameters of rigid ion models for NaNO 2 in…
The velocity of edge dislocations in 99.999% pure copper crystals has been measured as a function of stress at temperatures from 66°K to 373°K by means of a torsion technique. The range of resolved shear stress was 0 to 15 megadynes/cm2 for seven temperatures (66°K, 74°K, 83°K, 123°K, 173°K, 296°K, 373°K). Dislocation…
The Crystallization kinetics of molten polyethylene subjected to a constant shear stress were investigated theoretically and experimentally. The rate of crystallization depends on the difference of entropy (Δs) between the crystalline and molten state. The constant shear stress in the melt decreases Δs causing an abru…
Almost every kind of material and fabrication process now has to be used to meet the demands of ocean engineering, ranging as it does from hydrofoils to research submersibles, and from giant tankers to offshore drilling rigs. Some of the difficulties are obvious, for example when aircraft-like design procedures must b…
Abstract In the preparation of magnesium oxychloride cement from MgO and MgCl 2 .6H 2 O solution, MgO is sometimes replaced by partially calcined dolomite, MgO.CaCO 3 . In this paper, the suitability of dolomites for this purpose was studied by use of petrographic, d.t.a. and X ‐ray diffraction techniques. It is shown…
A technique has been developed for extracting one of the phases present in Ni-Co-Al-Ti-Cu-Fe permanent magnet alloys heat-treated to give optimum magnetic properties. Examination of such extracts by electron microscopy and electron-probe microanalysis has confirmed previously held theories that the precipitate is stro…
SUMMARY A new centric diatom, Microsiphona potamos gen. et sp. nov. (family Coscinodiscaceae), is described from the Little Miami River, Cincinnati, Ohio, where it occurred at cell densities ranging from 29 to 20,140/ml in surface grab samples during the period May 18–December 14, 1966, contributing an average of 11%…
The major features of the images of dislocation dipoles obtained by two-beam electron microscopy which enable dipoles to be identified and distinguished from other defects are discussed. The positions of stable equilibrium of dipoles in various f.c.c. and b.c.c. materials have been derived using linear anisotropic ela…
Transmission electron micrographs of replicas and glass chips mounted on carbon films can be obtained in the scanning electron microscope. The standard collection system is used and only slight modifications made to the specimen stage.
Photomicrographs are presented of a naval brass which has undergone dezincification, presumably by fresh water. Detailed analysis of them leads to the conclusion that dezincification must have occurred by the mechanism of redeposition of the copper.