Materials Literature
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An intergranular second phase, present as a film in a large‐grained MgAl 2 O 4 densified with LiF, was observed, on sequential heat treatment at 1500° C, to progressively reduce its area by first forming slender fingers which then break up into spheroid‐shaped islands. This “beading” process is an example of a Rayleig…
Abstract Experiments to produce polycarbosilazane resin and high‐strength silicon carbide–silicon nitride (Si x N y C z ) fibers as well as resin/fiber characteristics are reported. Polycarbosilazane resin was drawn into fibers from the melt and subsequently treated and pyrolyzed into Si x N y C z fibers. These materi…
The selective reflection is observed in a monodomain homeotropic cell of chiral smectic C liquid crystal (DOBA MBC). In conjunction with the refractive index, the structural helical pitch is determined as a function of temperature. The results agree well with our previous results obtained by diffraction technique as w…
The singularity index α of the asymmetric C(1s) x-ray photoelectron spectrum (XPS) of vitreous carbon is determined to be 0.19±0.01, independent of the interlayer separation of the graphitic layers. This result is interpreted within the framework of the many-electron theory; two mechanisms are suggested: (1) the modul…
The intensity and excitation wavelength dependence of the surface-enhanced Raman effect is measured on microlithographically prepared gold and aluminum particle surfaces. Comparison of enhancement relative to identically fabricated silver surfaces gives good agreement with particle-plasmon theories of surface-enhanced…
Abstract The kinetic aspects of the bisphenol‐A polycarbonate–polybutylene terephthalate exchange reaction are considered as a function of temperature and of the PC/PBTP ratio. The most likely mechanism is a direct reversible ester‐ester interchange reaction catalyzed by titanium residues present in commercial PBTP.
Polyaniline was electrodeposited on platinum and semiconducting (Cd‐chalcogenides, Si, GaAs , GaP ) electrodes from aqueous solution ( p H = 1 ) containing aniline. The electrochemical behavior of such films was examined in aqueous and nonaqueous solutions by cyclic voltammetry. Results show that the polyaniline film…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThermal degradation of sodium citrate solutions containing sulfur dioxide and thiosulfateGary T. Rochelle and Michael M. GibsonCite this: Ind. Eng. Chem. Process Des. Dev. 1982, 21, 4, 569–574Publication Date (Print):October 1, 1982Publication History Published online1 May 2…
Abstract Raman spectra of oriented sodium nitrite single crystals are reported. Half‐widths, peak frequencies and band shapes change when the temperature is varied from 30 to 513 K. Resolution of the Raman bands of the symmetric NO vibrations into contributions from ordered and disordered positions yield a temperature…
This paper describes the development of ultra-high strength 70- and 84-ton suspension insulators, and the results of various tests to confirm their performances. Also, the investigations into electrical characteristics were made on the insulator string assemblies consisting of them. For the future UHV transmission lin…
Tracer self‐diffusion coefficients for Er and Hf were measured in polycrystalline Er 2 O 3 ‐stabilized HfO 2 (fluorite phase) at compositions between 10 and 40 mol% Er 2 O 3 and temperatures between 1700° and 2033°C. In some instances, grain‐boundary coefficients were also determined. The Hf volume coefficients were g…
Surface oxidation of fusion‐cast CaF 2 in air was studied at 700°, 800°, and 900°C. Oxidation proceeds by a complex reaction mechanism involving creation of anion vacancies and formation of CaO, Ca(OH) 2 , and CaCO 3 . An equilibrium governed by the temperature and time of oxidation exists between formation and decomp…
The epichlorohydrin elastomers were discovered in early 1957 when the author's new vinyl ether coordination catalyst was explored for epichlorohydrin polymerization and yielded a new rubber, amorphous polyepichlorohydrin. This work quickly led to the discovery of unique new organometallic catalysts which facilitated t…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAddition compounds of alkali metal hydrides. 22. Convenient procedures for the preparation of lithium borohydride from sodium borohydride and borane-dimethyl sulfide in simple ether solventsHerbert C. Brown, Yong Moon Choi, and S. NarasimhanCite this: Inorg. Chem. 1982, 21,…
Abstract A short, critical review is provided on the utilization of surface techniques, particularly ESCA, for the study of metal and alloy corrosion problems. Some of the attributes and difficulties of these techniques are considered. An interrelated series of Cu systems are chosen as representative examples of the u…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDetermination of the onset of the dezincification of .alpha.-brass using x-ray photoelectron (ESCA) spectroscopyT. L. Barr and J. J. HackenbergCite this: J. Am. Chem. Soc. 1982, 104, 20, 5390–5394Publication Date (Print):October 1, 1982Publication History Published online1 M…
The thermal expansion coefficients of a number of phenacites [Be2SiO4, β-Si3N4, β-Sialon, α-LiAlSiO4, Zn2SiO4, CdAl2O4, and Zn2GeO4] at temperatures at and above the Debye temperature are analyzed in terms of the thermal Grüneisen parameter γ. The phenacites have γ values intermediate between adamantine crystals and q…
Optical absorption, luminescence, and Raman spectra were measured for sodium silicate glasses melted in air, containing about 85% Fe(III) and 15% Fe(II). Luminescence intensities for individual samples were compared. Three d-d bands in the optical absorption spectrum due to Fe(III) at about 26,000, 24,000, and 23,000…
Ultrasonic (20 kHz, 70 W) solution degradations of polystyrene, substituted polystyrenes, and poly(n-vinyl carbazole) have been carried in toluene and tetrahydrofuran at 27 and -20°C in the presence of flexible chain polymers. Polystyrene formed block copolymers at 27°C with stiff-chain polymer PVCz; however, in the p…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and structure of novel mononuclear and binuclear zerovalent platinum complexes involving coordination by tin centers to give heteropolymetallic arrays of three or five atoms. A unique bridging function for bivalent tin and a new class of platinum(0) dimersGordon W.…