Materials Literature
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Dielectric and pyroelectric behaviour of phenanthrene single crystals between 20 and 90°C have been investigated. Sharp peaks of ε have been observed during first heating of the samples. The pyroelectric charge in b-direction has been detected without a biasing field. The most probable explanation of all data availabl…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMathematical and experimental foundations of linear polycondensation modeling. 1. Modeling and simulation of linear, irreversible polycondensationM. R. N. Costa and J. VillermauxCite this: Ind. Eng. Chem. Res. 1988, 27, 3, 421–429Publication Date (Print):March 1, 1988Publica…
Scanning tunneling microscopy (STM) has been enormously \nsuccessful in solving several important problems in the geometric and electronic structure of homogeneous metallic and semiconducting surfaces. A central question which remains to be answered with respect to the study of \ncompound surfaces, however, is…
The magnetic and mechanical properties of zirconia-added NiZn ferrite were studied. It was found that the addition of small amounts of ZrO/sub 2/ improves their magnetic properties to a great extent. Magnetic losses at 10 MHz decreased by a factor of two with no significant change in permeability whereas the flexural…
Abstract The study of 13 C NMR spectra of polystyrene thermally obtained on clays shows that thermal polymerization of styrene on these minerals proceeds by two parallel reaction mechanisms: the radical mechanism due to the thermal effect, and the cationic mechanism in which the initiatory cation H + is provided by th…
Sulfuric acid is an important reactant and by-product in the mining and metal extraction industries. Corrosion in sulfuric acid is dependent on both the concentration of the acid and the type of impurities present in the acid. The behavior of a variety of stainless steels and Ni-bse alloys is examined as a function of…
The static hysteresis model which is based on Frohlich equations is extended to simulate the dynamic B-H behavior including hysteresis. In order to describe the dynamic model, the following conditions are required: the magnetizing curve, the relationship between H/sub c/ with H/sub m/ (or B/sub m/) and B/sub r/ with B…
The effects of elevated temperature air exposure at 75 degrees , 100 degrees , 125 degrees , and 150 degrees C on the performance of sintered Nd-Fe-B type permanent magnets was investigated. The observations include a comparison of the initial and final demagnetization curves after long-term aging in excess of 5000 h,…
The scientific and patent literature on polymerization of vinyl chloride (VCM) is very extensive. A comprehensive review covering the literature up to about 1984 was recently done by Felger (1986). Some less comprehensive but very useful monographs have also been published fairly recently (see Burgess, 1982, and Butte…
A mixture of tetragonal and monoclinic 2Y˙ZrO 2 (2 mol% Y 2 O 3 –ZrO 2 ) powder was treated from 400° to 800°C and from 4 to 7 GPa for 30 min. The products were identified by powder XRD, Raman spectroscopy, and TEM. Results indicated that an orthorhombic phase was synthesized at T=400° to 600°C and P>4 GPa. The lat…
High sensitivity saturation magnetostriction measurements were performed for some Co-based metallic glasses. Tensile stress dependence of magnetostriction at elevated temperatures was investigated. The results obtained are discussed in terms of the pair-ordering and the preferred distribution of atomic bonds or two-le…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of thermal interconversion between cis,cis-1,3,5-octatriene, cis,cis,cis-2,4,6-octatriene, and cis,cis,trans-2,4,6-octatrieneJohn E. Baldwin and V. Prakash ReddyCite this: J. Org. Chem. 1988, 53, 6, 1129–1132Publication Date (Print):March 1, 1988Publication History…
ABSTRACT Valve morphogenesis in two Surirellae (S. ovalis Brebisson and S. robusta Ehrenberg) is described. Mitosis takes place at the broad end of the cell. After cleavage, a new Microtubule Center (MC) arises near each spindle pole and moves to the adjacent plasmalemma. Soon, a specific group of microtubules (MTs) e…
Abstract The structural parameters of two modifications of AgInS 2 are determined. The geometrical model of phase transition is discussed. Crystallochemical comparison reveals the absence in the two modifications of significant differences in atomic interactions. The changes in atomic interaction with the temperature…
Abstract A comprehensive Mössbauer spectroscopic and X-ray diffraction study of six purified glauconites is presented. The Mössbauer spectra were computer-fitted with three Fe 3+ and three Fe 2+ doublets, both Fe species occupying the trans -OH and two cis -OH octahedral sites. In addition, a seventh smaller doublet i…
Abstract The effects of the nature of the polyols used in polyurethane (PUR) synthesis on the structural transformations after ageing by UV irradiation has been studied. The investigations were performed on PUR prepared from polyester and polyether diol oligomers. The characterization of the samples before and after a…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHexagonal lithium molybdate, LiMoO2: a close-packed layered structure with infinite molybdenum-molybdenum-bonded sheetsLorraine E. Aleandri and Robert E. McCarleyCite this: Inorg. Chem. 1988, 27, 6, 1041–1044Publication Date (Print):March 1, 1988Publication History Published…
It has been traditional to interpret the strength of ceramics in terms of the mean grain size. This paper investigates, critically, the use of strength vs mean grain size{sup {minus}1/2} plots and shows them to be inconsistent with fracture mechanisms theory. It is suggested that strength be plotted against maximum gr…
Abstract To study the effect of potassium titanium oxyoxalate on the esterification reaction of terephthalic acid (TPA) and ethylene glycol (EG) in the first tank reactor of TPA/EG continuous esterification, experiments at various addition rates of potassium titanium oxyoxalate were made in the pilot plant. Potassium…
Large (5 × 3 × 3 cm3) crystals of the organic nonlinear optical material MBA-NP have been prepared by growth from solution, in an optically and structurally highly perfect state. Oriented cut and polished specimens were examined by the Maker fringe technique at a wavelength of 1·064 µm. Analysis of the data yielded d…