Materials Literature
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Oxygen self‐diffusion in alumina single crystals was investigated, using the proton activation technique to measure the 18 O profiles after the samples had been exchanged with an 18 O‐enriched gaseous environment. In the temperature range 1750 to 1950 K, the diffusion coefficient for a set of Czoch‐ralski‐grown sample…
Recent work on zone‐melting recrystallization of Si on amorphous insulating substrates using a moveable‐strip heater oven is described in detail for the first time. A (100) texture is obtained if the Si is encapsulated with or a composite of . An encapsulation layer of prevents agglomeration and ensures a smooth surfa…
We derive the thickness profiles of metallic transmission-grating bars that maximize either the power throughput into the mth diffracted order or the ratio of the mth-order diffracted power to the total output power (in the soft-x-ray range). The derivation is performed for both general and symmetric bar shapes and fo…
The preparation of the cis and trans isomers of the kinetically labile bis glycinato copper(II) has a number of advantages including its facility, economy, ready theoretical interpretation, and biological relevance.
It was reported that the addition of a small amount of titanium (0.5 - 3.99%) to a Cu-13.93%Al-3.36%Ni ternary alloy resulted in a remarkable grain-refining. The original grain-size of about 750 microns under hot-rolled and quenched conditions of the ternary alloy was reduced to that of the order of about 100 microns…
The genus Navicula is the major constituent of the sea ice diatom community of Manitounuk Sound, Hudson Bay. Taxonomical information is given for 43 taxa of the genus Navicula by means of complete illustrated descriptions. One new species and six varieties are described and a new combination is proposed.
Abstract Euhedral crystals of the low-temperature mineral lansfordite, MgCO 3 · 5H 2 O, have been prepared from saturated magnesium bicarbonate solutions at temperatures below 10°C. The crystals are monoclinic P 2 1 / a with a = 12.4758(7), b = 7.6258(4), c = 7.3463(6)Å, β = 101.762(6)°, V = 684.24Å 3 , D calc. = 1.69…
Microstructure effects on the strength of U02 pellets have been investigated. The strength was measured at room temperature using a biaxial flexure technique in which thin disk specimens, sliced from U02 pellets, were fractured by ring loading in the specimen center. The strength of U02 was reduced, in all cases, by i…
The x-ray induced visible luminescence of SrTiO3 has been studied in the range 15–300 °K. An apparently single-emission band at 500 nm has been observed whose efficiency abruptly decreases at ∼30 °K. This luminescence band is proposed to be intrinsic and associated with the decay of a relaxed Ti+3O−53 exciton. After 1…
Abstract We suggest a theory of Ψ‐condensation, based on the assumption that a compact DNA particle is a globule, and specifically that a polymer solution is a strongly fluctuating system and that double‐stranded DNA is a stiff homopolymer single‐stranded chain. We show the DNA globule as it appears in a dilute poly(e…
Landau theory proved itself appropriate for describing phase transitions in systems such as ferroelectrics and ferromagnets. Primarily Landau established the theory for second order phase transitions. Later on Devonshire generalized Landau's approach to first order transitions. The essential point of Landau theory is…
Abstract The effect of carbon black on the processing characteristics and physical properties of jute fiber‐reinforced composites and the role of silica and carbon black in promoting the adhesion between jute fiber and natural rubber have been studied. It was found that presence of silica is not essential to develop a…
Abstract Economic, technological, and regulatory pressures gradually narrow the chemical variety of polymers: in 1975, the market share of polyethylene was 40 percent, poly(vinyl chloride), 23 percent, polystyrene, 12 percent, and polypropylene, 11 percent, adding up to 86 percent of all thermoplastics (1‐3). The same…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTGold clusters. Tetrakis[1,3-bis(diphenylphosphino)propane]hexagold dinitrate: preparation, x-ray analysis, and gold-197 Moessbauer and phosphorus-31{proton} NMR spectraJ. W. A. Van der Velden, J. J. Bour, J. J. Steggerda, P. T. Beurskens, M. Roseboom, and J. H. NoordikCite t…
The characteristics of equilibrium first-order phase changes of the grain boundaries themselves are such that it leads to a definition of grain boundary phases in which smoothly curving boundaries are of the same phase. Different grain boundary phases coexist at facet edges and corners. The phase rule, phase diagrams,…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of decomposition of tetrathionate, trithionate, and thiosulfate in alkaline mediaErnest. Rolia and Chuni L. ChakrabartiCite this: Environ. Sci. Technol. 1982, 16, 12, 852–857Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Publi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTOrganic sonochemistry. Sonic acceleration of the Reformatsky reactionByung Hee Han and Philip BoudjoukCite this: J. Org. Chem. 1982, 47, 25, 5030–5032Publication Date (Print):December 1, 1982Publication History Published online1 May 2002Published inissue 1 December 1982https…
The electrochemical reduction of α‐, γ‐, δ‐, and amorphous FeOOH was investigated. These oxides were applied as pastes to weathering steel substrates and galvanostatically reduced in solutions of 0.1 M Na 2 SO 4 . Raman and infrared spectroscopy were used to monitor the reaction products. Amorphous, γ ‐ , and δ ‐ FeOO…
Abstract The tensile strength of oriented polyethylene filaments is discussed in relation to molecular weight. Short‐term tensile properties at room temperature were obtained in our laboratory and from the literature for polymer samples covering the molecular weight ( M w ) range from 54 × 10 3 to 4 × 10 6 , and polyd…
Abstract The interaction of the natural marine polymer chitin and its deacetylated derivative chitosan with chromium has been investigated. The uptake of chromium from aqueous solution was determined from changes in concentration as measured by atomic absorption spectroscopy. The uptake of Cr(III) on chitosan was sign…