Materials Literature
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The crystal structure of trans-1,4-polybutadiene has been reported by Natta et al. to be pseudo-hexagonal below its solid-phase transition temperature. In the present X-ray structure analysis, it is revealed that the crystal belongs to the monoclinic system with the space group P21/a. The unit cell, with the lattice c…
It is shown theoretically that, for non-Kramers paramagnetic ions, the second-order Raman phonon process gives a spin–lattice relaxation rate varying as T 5 at low temperatures. This new relaxation rate for non-Kramers ions is similar to the one discussed by Orbach and Blume for multilevel Kramers ions. An unusual fea…
Incoloy(1) nickel-iron-chromium Alloy 825 can become sensitive to intergranular attack by exposure to temperatures in the 1200-1400 F (649-760 C) range. Sensitivity to intergranular attack (as measured by the Huey test) can be correlated to the presence of a chromium-depleted area adjacent to the grain boundary. This…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe disordered and β-conformations of silk fibroin in solutionEisaku. Iizuka and Jen Tsi. YangCite this: Biochemistry 1968, 7, 6, 2218–2228Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pubs.acs.org/doi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis of carbon macrocycles to C120E. Wasserman, D. A. Ben-Efraim, and R. WolovskyCite this: J. Am. Chem. Soc. 1968, 90, 12, 3286–3287Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pubs.acs.org/doi/…
The number of ionizations on a given j shell in any electron-bombarded target has been calculated analytically by means of the Bethe formulae. A general formula for the atomic number correction has been derived in the form of an equation using parameters that are functions of target composition and accelerating voltag…
Low-temperature conductivity measurements on glasses containing transition-metal oxides TiO2 and V2O5 reveal a sharp break in the slope of the dependence of log conductivity upon reciprocal temperature. At low temperatures, the slope corresponds to a low-activation-energy process (0–0.2 eV) while at high temperatures…
New permanent magnet materials containing rare-earth elements (RE) have been discovered. For the most part, these alloys are based on the hexagonal intermetallic compounds, Co5RE. Replacement of cobalt with copper in some of these rare-earth compounds results in solid materials with substantial permanent magnet proper…
Five glasses and four polycrystalline compounds of the lithium borate system have been subjected to γ irradiation at 77°K and subsequently examined by ESR techniques at 9.1 and 35 GHz while maintaining this low temperature. The familiar “five-line-plus-a-shoulder” spectrum is observed at X band for both the Li2O·4B2O3…
The replacement of magnetite by hematite is not by octant sectors but is independent of sample coordinates and is penetrative to at least the scale of developed \[111\] parting. Anisotropy increases with depth into the octahedron. Hematite c-axis orientation perfection occurs 5 mm deep into the crystal. The replacemen…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAnionic ring-opening polymerization of thiolactonesCharles G. Overberger and Jurgen K. WeiseCite this: J. Am. Chem. Soc. 1968, 90, 13, 3533–3537Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pubs.acs.or…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new structural type for heteropoly anions. The crystal structure of (NH4)2H6(CeMo12O42).12H2ODavid D. Dexter and J. V. SilvertonCite this: J. Am. Chem. Soc. 1968, 90, 13, 3589–3590Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published…
Single crystals of Pb(Fe 1/2 Ta 1/2 )O 3 were grown from ternary melts with excess PbO. The crystals, having cubic perovskite structure at room temperature, undergo a ferroelectric phase transition at about 243°K, changing to rhombohedral structure. The dielectric constant passes through a maximum of nearly 9500 at 1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMagnetic, Moessbauer, and structural studies on three modifications of FeMoO4A. W. Sleight, B. L. Chamberland, and J. F. WeiherCite this: Inorg. Chem. 1968, 7, 6, 1093–1098Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSilylene chemistry. I. The thermolysis of methoxypolysilanesWilliam H. Atwell and Donald R. WeyenbergCite this: J. Am. Chem. Soc. 1968, 90, 13, 3438–3443Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://pu…
Abstract Die Nitrierung und Denitrierung von α‐Eisen durch die Reaktion magnified image wurde in einer Durchströmungsapparatur an dünnen Eisenfolien zwischen 300 und 800 °C mit Hilfe von Widerstandsmessungen untersucht. Unter diesen Bedingungen werden Aussagen zur Kinetik der Oberflächenreaktionen erhalten. Die Reakti…
High frequency cyclic voltages on a specimen surface have been studied pictorially, in the scanning electron microscope, by applying the principle of the sampling oscilloscope. The electron beam in the microscope column is pulsed, and the phase varied with respect to that of the waveform on the specimen. With 10 ns el…
It is shown how the method of measuring fabric drape by supporting a circular specimen of fabric between smaller horizontal circular plates has been modified to allow a more sensitive test to be made on very stiff and very limp fabrics. The use of diverging light instead of parallel light is described, and the correct…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreexponential factors for solid-state thermal decompositionHerman F. CordesCite this: J. Phys. Chem. 1968, 72, 6, 2185–2189Publication Date (Print):June 1, 1968Publication History Published online1 May 2002Published inissue 1 June 1968https://doi.org/10.1021/j100852a052RIGH…
The optical absorption and fluorescence spectra of two spinels, ZnAl2O4:Cr3+ and MgAl2O4:Cr3+ have been measured at various temperatures between 2°K and room temperature. The data have been fitted to a crystal-field theory which includes spin-orbit coupling and the trigonal field of the D3d site. The parameters for a…