Materials Literature
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2e ordre créent des singularités de certaines viscosités et constantes élastiques en phase nématique. Le comportement critique des constantes élastiques a déjà été calculé par P. G. de Gennes dans le régime hydrodynamique q03BE ~ 1. En partant des mêmes hypothèses et en utilisant comme outil de travail la théorie de l…
The physics of quasi-one-dimensional solids which undergo a Peierls distortion, such as the organic material TTF-TCNQ (tetrathiofulvalinium-tetracyanoquinodimethan) is discussed. In particular, the effect of fluctuations into the Fr\"ohlich superconducting state on the free energy and the electrical conductivity is ex…
ADVERTISEMENT RETURN TO ISSUEPREVArticleBiochemical significance of porphyrin .pi. cation radicalsDavid Dolphin and Ronald H. FeltonCite this: Acc. Chem. Res. 1974, 7, 1, 26–32Publication Date (Print):January 1, 1974Publication History Published online1 May 2002Published inissue 1 January 1974https://pubs.acs.org/doi/…
Testing in 10-MPa (1500-psi) hydrogen did not reduce the notched strength of irradiated Inconel 718 or A286; however, irradiated Ti-5Al-2.5Sn suffered reductions in notched strength of 6.9 percent. Likewise, irradiated CW 301 stainless steel lost 81 percent of the notched strength in 10-MPa (1500-psi) hydrogen. For hy…
It can be shown that if amplitude as well as momentum changes during phonon scattering events are taken into account, the line shape associated with infrared- or Raman-active lattice modes can be of the Lorentz or Van Vleck-Weisskopf form as well as of the damped-oscillator form. An expression is derived for the susce…
The slip mode operative in the c-axis compression of magnesium was examined using precisely-oriented single crystals. From recorded stress-strain curves and observations with light and transmission electron microscopes, it was found that (1) the {1122} <1123> slip system operates at all temperatures investigated (from…
A study is made of the effect of fast neutrons on the electrical conductivity and thermoelectric power and also the neutron-induced defects in β-Ga2O3. It is found that the conductivity decreases while the thermoelectric power increases after an irradiation of about 1017 nvt. This is explained by assuming that the def…
The total synthesis of enmein (1) is reported. The diol acetal, ent-3β,20-epoxy-3-methoxy-17-norkaurane-6α,16α-diol (3) was used as the important relay compound.
Abstract Bismuth orthoborate BiBO 3 , a non‐existent compound after the Bi 2 O‐B 2 O 3 phase diagram, has been obtained by melting a mixture of H 3 BO 3 and Bi 2 O 3 corresponding to the BiBO 3 composition and subsequent cooling. Two different phases are obtained, depending on the cooling conditions. Infrared and Rama…
Electroinitiated polymerization of tetrahydrofuran (THF) was accomplished in 1 M LiClO 4 ‐ THF organic electrolyte solutions by anodic electrolysis on platinum electrodes in a three‐compartment cell. THF was found to polymerize to form a viscose gel at 25°C. The rate of polymerization was followed by measuring the ele…
The dependences of the radiationless relaxation rate constant on the effective mediating phonon energy, the equilibrium displacement of the adiabatic surfaces, the energy gap, and the temperature are numerically examined in terms of a generalized theoretical rate expression derived from quantum statistical theory. Spe…
Abstract : The TPRC Data Series published in 13 volumes plus a Master Index volume constitutes a permanent and valuable contribution to science and technology. This 17,000 page Data Series should form a necessary acquisition to all scientific and technological libraries and laboratories. These volumes contain an enorm…
Corrosion of pure and amalgamated zinc in pure concentrated solutions was investigated using two methods: ( a ) galvanostatic measurements of the kinetics of hydrogen evolution with electrodic assessment of corrosion properties of the system, and ( b ) volumetric measurement of the hydrogen evolution reflecting direct…
Grain size dependence of the yield stress in polycrystalline copper-aluminum and copper-nickel alloys is measured at 77, 194 and 293°K. It is found that the Hall-Petch relation is valid for these materials. The Petch slope ky is nearly independent of the temperature, but increases with increasing solute concentration.…
The rare earth‐Fe2 (RFe2) compounds possess huge magnetic anisotropies and magnetostrictions at room temperature. This, coupled with a relatively high Curie temperature and magnetic saturation, makes these alloys attractive for various applications, including magnetostrictive transducers and permanent magnets. A varie…
An electron microscope study is made on isothermal decomposition in Alnico 8 alloy as annealed around 800°C for 10–90 min in a magnetic field. The results obtained are found to agree well in many essential aspects with Cahn’s theoretical predictions on spinodal decomposition in a ferromagnetic cubic alloy. In the case…
Boron arsenide films have been deposited on the basal plane of hexagonal silicon carbide and {111} oriented sodium fluoride and silicon substrates at 800°–850°C by the thermal decomposition of a diborane‐arsine mixture in a hydrogen atmosphere. Adherent films were deposited on silicon carbide substrates and were ident…
Equipment and procedures used in performing tension, fracture mechanics, fatigue, and creep tests on metal specimens in high-pressure hydrogen are described. Important test parameters, in particular, hydrogen purity and methods of achieving high purity are considered. The interpretation and use of data obtained from t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStereochemistry of low-spin cobalt porphyrins. IV. Molecular stereochemistry of (1-methylimidazole)-.alpha.,.beta.,.gamma.,.delta.-tetraphenylporphinatocobalt(II)W. Robert ScheidtCite this: J. Am. Chem. Soc. 1974, 96, 1, 90–94Publication Date (Print):January 1, 1974Publicati…
A review has been prepared of the metallurgical factors affecting the hardenability and mechanical properties of boron-treated low-alloy steels. Detailed experimental work has been carried out to clarify the following controversial aspects of these steels: (a) occurrence of boron in steels; (b) influence of boron cont…