Materials Literature
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A c-axis alexandrite laser rod was longitudinally pumped in the 450–560 nm region with argon ion and dye lasers. In addition to the sharp R lines and broadband phonon-assisted transitions typical of mirror site Cr3+ ions in alexandrite, room temperature fluorescence spectra displayed characteristics in the 690–730 nm…
A micromechanical model for strength behavior as a function of grain size in two‐phase materials with thermal expansion mismatch and in single‐phase materials with thermal expansion anisotropy is presented. The strength vs grain‐size plot is interpreted in terms of internal stresses and the ratio of grain to flaw size…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTFormation of trans-M(O)2(CO)4 (M = Mo and W): intermediates in the photooxidation of matrix-isolated M(CO)6Joseph A. Crayston, Matthew J. Almond, Anthony J. Downs, Martyn Poliakoff, and James J. TurnerCite this: Inorg. Chem. 1984, 23, 20, 3051–3056Publication Date (Print):Se…
Measurements of the thermoelectric power along the three crystallographic axes of N-methyl-N-ethylmorpholinium bistetracyanoquinodimethane, ${\mathrm{MEM}(\mathrm{TCNQ})}_{2}$, in the temperature range 280-360 K are reported. The first-order metal-insulator phase transition at 338 K is observed as a discontinuous chan…
Abstract Die neuen Verbindungen K 6 Ge 2 S 6 und K 6 Ge 2 Se 6 kristallisieren monoklin in der Raumgruppe C2/m (Nr. 12) mit den Gitterkonstanten Die Verbindungen sind einander isotyp und bilden die K 6 Si 2 Te 6 ‐Struktur aus. Na 6 Ge 2 Te 6 kristallisiert monoklin in der Raumgruppe P2 1 /c (Nr. 14) mit den Gitterkons…
Abstract The results obtained from this study of kaolinite dehydroxylation explain why different investigators have ascribed both first-order kinetics and a diffusion mechanism to this reaction. The fact that activation energies reported by these workers agree well, in spite of the different kinetics assumed when perf…
In multiphase Sm(Co,Fe,Cu,Zr)7.6alloys the relations between the microstructure and magnetization processes have been analysed after different annealing treatments by investigations of the domain structure and of the characteristic properties of the hysteresis loop. It is shown that large coercive fields may be attrib…
Magnetic noises in rapidly quenched amorphous magnetic materials were examined. Magnetic noises are observed as the fluctuations of the induced voltage wave forms of the magnetic cores on every cycle of the alternating exciting field. Fe, Ni, and Co base alloys were tested, and the following results have been obtained…
Abstract The effect of ionizing radiation on the melting behavior of high‐density and low‐density polyethylene was examined with data obtained by differential scanning calorimetry. Melting temperatures and fusion endotherms were obtained after absorbed doses of gamma radiation up to 3 MGy. The changes in melting tempe…
The magnetostrictive properties of single crystal Tb.27Dy.73Fe2was examined under compressive loads up to 48 MP a. Magnetostrictions > 1.8 × 10-3were observed for stresses greater than 20 MPa. Magnetization and magnetostriction were calculated for the magnetization rotation model, which was extended to include cubic a…
Abstract The heat of fusion Δ H f of 66 nylon has been determined by use of the Clapeyron equation. Measurements of Δ H f and the unit‐cell parameters on molding pellets show that this material contains the α 2 crystal phase, which is less dense than the α 1 phase obtained by crystallization from solution. The value o…
The technique of extended electron energy loss fine structure (EXELFS) using an electron energy loss spectrometer fitted to a transmission electron microscope (TEM) has been applied to a study of the structure of the thin layer of amorphous alumina (Al2O3) which is formed on aluminium by anodic oxidation in neutral so…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCatalyst preparation procedure probed by EXAFS spectroscopy. 2. Cobalt on titaniaKazuyuki Tohji, Yasuo Udagawa, Shuji Tanabe, Takashi Ida, and Akifumi UenoCite this: J. Am. Chem. Soc. 1984, 106, 18, 5172–5178Publication Date (Print):September 1, 1984Publication History Publi…
A model system consisting of vacuum-deposited aluminum on glass was developed to demonstrate the effectiveness of cavitational activity (occurring within the cooling water supply of a dental ultrasonic scaler) in the removal of particulate material from solid surfaces. The amount of solid material removed from the mod…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOccurrence of electron transfer in the reduction of organic halides by lithium aluminum hydride and aluminum hydrideEdward C. Ashby, R. N. DePriest, A. B. Goel, B. Wenderoth, and T. N. PhamCite this: J. Org. Chem. 1984, 49, 19, 3545–3556Publication Date (Print):September 1,…
Abstract During the development of chemical methods for determining the epoxide content of epoxidised natural rubber (ENR) two methods were found to give results which were identical but which showed a progressive divergence from values obtained by absolute instrumental methods as the level of epoxidation increased. S…
Within the same water body, morphological variants of the same diatom species often coexist. Observations of such phenodemes of Navicula pupula and Amphora ovalis show that, when sexual, they either fail to attract or fail to recognize each other and do not interbreed. Since in both species the morphological and repro…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOptical and electron spin resonance study of cation and cation-crown ether induced dimerization of tetrakis(4-sulfonatophenyl)porphyrinT. K. Chandrashekar, Hans Van Willigen, and M. H. EbersoleCite this: J. Phys. Chem. 1984, 88, 19, 4326–4332Publication Date (Print):Septembe…
SUMMARY The presence of imogolite or other poorly crystalline aluminosilicates in the lower B horizons of podzols can be explained by neoformation from silica in the percolating soil solution and aluminium species liberated from their organic bond by activity of micro‐organisms. There are physicochemical arguments ref…
Hexagonal ferrites with M, Y and W structures were prepared from powders obtained by the decomposition of organometallic salt (citrate) solidified solutions, Due to the improved reactivity of these powders with respect to the classical ceramic ones, a number of advantages were obtained: pure hexaferrites were produced…