Materials Literature
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Results from isothermal ageing of a commercial nickel-base alloy are presented. Particle sizes are determined by electron microscopy. The particle coarsening is found to obey the Lifschitz-Wagner theory. The volume fraction of γ′ particles is 0.15. The proof stress is determined for a series of ageing times. The Taylo…
We give the experimental evidence of first order magnetization processes in a W- -type hexaferrite single crystal having composition BaZn1.38Co.62Fe16O27. The nature and the characteristics of the transition change with temperature from 77 to 250°K. The observed effects are discussed on the basis of a phenomenological…
Glauconite dates obtained by conventional K-Ar and 40 Ar/ 39 Ar age spectrum techniques from Palaeocene horizons in Kent are examined against a Palaeogene K-Ar time-scale derived from the Tertiary igneous rocks of the North Atlantic region. Isotope ratio plots (correlation diagrams) are used to analyse and test the va…
Résumé Pour les hydrates à ‘deux couches’ des vermiculites issues des phlogopites 1 M, saturées par Li, Na, Ca, Mg ou Ba, nous avons rencontré quatre modes d'empilement des feuillets. Un seul (V III ) présente une structure ordonnée tridimensionnellement. Les trois autres (V I , V V et V VII ) sont des structures semi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhotoreduction of tetraphenylporphyrins by amines in the visible. Photochemical syntheses of reduced tetraphenylporphyrins and the mechanism of photoreductionY. Harel and J. ManassenCite this: J. Am. Chem. Soc. 1978, 100, 19, 6228–6234Publication Date (Print):September 1, 19…
Al-5%Mg, Ag, Au, Cu-l0%Ni, and Ni in the form of bars have been deformed to large strains by rolling at 20°C, and their microstructures determined by thinfoil transmission electron microscopy. Tensile tests have been carried out on the rolled specimens, and from the results obtained stress/true rolling strain curves h…
Coldworking the material near the edge of a fastener hole is one important means of increasing fatigue life. The stresses, strains, and location of the boundary between elastic and plastic regions have been analyzed by various theoretical studies. The purpose of this research is to experimentally evaluate the theories…
Abstract The action of solid surfaces coated with monomolecular films of amphiphilic compounds (especially lecithins) on adjacent liquid crystal phases resulting in an uniform homeotropic orientation has been investigated. The quality of orientation was found to be effected by molecular structure of the amphiphilics a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of (2R,4'R,8'R)-.alpha.-tocopheryl acetate (vitamin E acetate) using [3,3] sigmatropic rearrangementKa-Kong Chan, Anthony C. Specian Jr., and Gabriel SaucyCite this: J. Org. Chem. 1978, 43, 18, 3435–3440Publication Date (Print):September 1, 1978Publication History…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCalculation of Three-Dimensional Elastic Constants of Polymer Crystals. 1. Method of CalculationKohji Tashiro, Masamichi Kobayashi, and Hiroyuki TadokoroCite this: Macromolecules 1978, 11, 5, 908–913Publication Date (Print):September 1, 1978Publication History Published onli…
Several types of insulator strings covered with ice or snow were tested for ac, dc, and switchings impulse voltages. Reductions of flashover voltage were noted for all voltage types. These reductions were more acute on ice or snow covered insulator strings than on salt contaminated strings when deposits of salt were l…
The thermal degradation of PVC was studied at 190°C in pure nitrogen and nitrogen containing 10, 20, and 40% HCl (by volume). The rate of dehydrochlorination was determined by gravimetry. Degradations in nitrogen were followed with conductometry in addition. Changes in molecular weight distribution and degree of long-…
Lactose killing is a peculiar phenomenon in which 80 to 98% of the Escherichia coli cells taken from a lactose-limited chemostat die when plated on standard lactose minimal media. This unique form of suicide is caused by the action of the lactose permease. Since uptake of either lactose or galactose by the lactose per…
A method for the purification of yeast K+-activated aldehyde dehydrogenase is presented which can be completed in substantially less time than other published procedures. The enzyme has a different N-terminal amino acid from preparations previously reported, and other small differences in amino acid content. These dif…
The axial electric field gradient (EFG) at the Eu site of cubic pyrochlore ${\mathrm{Eu}}_{2}$${\mathrm{Z}}_{2}$${\mathrm{O}}_{7}$ (where $Z=\mathrm{T}\mathrm{i},\phantom{\rule{0ex}{0ex}}\mathrm{R}\mathrm{u},\phantom{\rule{0ex}{0ex}}\mathrm{I}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{M}\mathrm{o},\phantom{\rule{0ex}…
Hyperfine structure observed at g′≃9.4 and g′≃4.3 in the EPR spectrum of Mn2+ in several glasses is analyzed on the basis of the theory of Griscom and Griscom [J. Chem. Phys. 47, 2711 (1967)] and Aasa [J. Chem. Phys. 52, 3919 (1970)]. The complex hyperfine structure at g′=4.3 is found to be a superposition of three se…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic exchange interactions in binuclear transition-metal complexes. 17. Benzidine and p-phenylenediamine, extended aromatic diamine bridging ligands in binuclear copper(II) 2,2',2''-triaminotriethylamine and vanadyl bis(hexafluoroacetylacetonate) complexesTimothy R. Felt…
Abstract The broad‐line proton NMR spectra of polyethylene are separated into three components (broad, medium, and narrow) corresponding to the crystalline and two kinds of amorphous protons, respectively. All amorphous protons are found to be mobile above 210°K. The unusually low molecular mobility in the amorphous r…
Radicals are stabilized by simultaneous substitution with a donor (X) and an acceptor group (Y). Thus (1) and isobutyronitrile radicals do not give a polymer but the radical (2) which is stable when hot.
Complete sets of measurements are reported of the elastic, dielectric, optical, and viscous properties of new liquid-crystal mixtures for twisted nematic displays. Their optical and capacitive threshold voltages were shown to be identical and were used to determine the twist elastic constants k22. The splay (k11) and…