Materials Literature
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Ferroelectric thin films of BaTiO3 have been successfully deposited on n-type silicon substrates at temperatures above 500 °C by rf sputtering in an O2/Ar atmosphere. Analysis by x-ray diffraction patterns show that films deposited at room temperature are amorphous. At temperatures above 500 °C, crystalline BaTiO3 fil…
The widely held view that Al and Fe are transported from A2 to B horizons in podzols in the form of fulvate complexes cannot account satisfactorily for the formation of Bs horizons rich in allophane, although this can be the dominant illuvial horizon in Iron Podzols, and a major feature of the B horizon of Iron Humus…
Iron was ion implanted with He and deuterium (D) and then heated at a constant rate of 2 K/min. The evolving depth distribution of the D was monitored using the nuclear reaction 2D(3He,p)4He, and resulting data were analyzed by applying the diffusion equation with appropriate trapping terms. Two defect traps for D wer…
The phosphocarrier protein, IIIGlc, of the phosphoenolpyruvate:glycose phosphotransferase system (PTS) was purified to homogeneity by two methods. The first method utilized ion exchange and gel filtration chromatography, isoelectric focusing, and polyacrylamide gel electrophoresis, and required several weeks for compl…
Abstract High‐density polyethylene up to about 30% by weight was melt‐mixed with polypropylene and short‐glass‐fiber‐reinforced polypropylene. The presence of high‐density polyethylene and glass fibers in the polypropylene matrix affects its crystallization characteristics, which were studied with the help of differen…
The phosphorylation of Enzyme I is the first step in the phosphotransfer reaction sequence catalyzed by the phosphoenolpyruvate:glycose phosphotransferase system (PTS) from Salmonella typhimurium. The characterization of phospho approximately Enzyme I and the reactions in which it participates are described in this re…
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…