Materials Literature
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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…
A commercial ceria‐stabilized tetragonal zirconia polycrystal is shown not to degrade at low temperatures. Slight strength decrease is found for elevated‐temperature treatments, which is not related to formation of the monoclinic phase. A possible mechanism to explain the behavior based upon the ferroelastic nature of…
Small loops and stacking fault tetrahedra of sizes 1 to 10 nm were created during irradiation of copper with 14 MeV neutrons at room temperature. The electrical resistivity of these defect clusters has been investigated using a combination of resistivity and electron microscopy techniques. The dislocation specific res…
Polycrystalline samples of SrMe/sub 2/Fe/sub 16/O/sub 27/ (SrMe/sub 2-/W) with Me/sup 2+/=Zn, Co, Ni, Mn, Mg, Cu, and Sr/sub 2/Zn/sub 2/Fe/sub 28/O/sub 46/ (SrZn-X) hexagonal ferrites have been prepared by the chemical coprecipitation method. The main steps of W- and X-phase formation have been evidenced by means of M…
Nonlinear optical crystals appear very attractive due to their potential applications in optical signal processing. We have investigated several strategies in order to get efficient organic nonlinear optical crystals having enhanced quadratic responses and, more particularly, high efficiencies for second harmonic gene…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTWhole-pattern approach to structure refinement problems of fibrous materials: application to isotactic polypropyleneA. Immirzi and P. IannelliCite this: Macromolecules 1988, 21, 3, 768–773Publication Date (Print):March 1, 1988Publication History Published online1 May 2002Pub…
The potassium selenostannate(IV) K 4 Sn 3 Se 8 has been prepared by methanolothermal reaction of K 2 CO 3 with elemental Sn and Se at 190 °C and its structure established by X-ray structural analysis. The unit cell contains isolated [Sn 3 Se 8 ] 4- anions consisting of a central SnSe 4 -tetrahedron edge-bridged to two…
The conductivity of a random-resistor model, recently proposed for dispersed ionic conductors, is calculated using the effective-medium approximation. The results are compared with Monte Carlo simulations (MCS) for two- and three-dimensional systems. This simple analytical approach describes satisfactorily both the te…
Abstract Raman spectra of some indo‐, thia‐ and selena‐carbocyanine dyes have been measured. The bands are assigned to the modes associated with the methine chain, end chromophore and methyl/ethyl group based on a comparison of the positions of the bands for a series of dyes with similar structures and those for 1,2,3…
Das bekannte, äußerst reaktive [18]Annulen 1 und das hypothetische Isomer 2 sollten sich durch CH 2 ‐ und CHCH‐Gruppen als innere bzw. äußere Brücken stabilisieren lassen. Die entsprechenden Kohlenwasserstoffe 3 bzw. 4 sind nicht bekannt, obwohl sie als Bindeglieder zwischen den nicht‐natürlichen Annulenen und dem Po…
Abstract The KAHR model of structural relaxation has been extended to include the effects of pressure upon the retardation times of glass‐forming materials. The previously used methodology is applied with a continuous distribution of retardation times of the fractional exponential form. Several forms of the pressure d…