Materials Literature
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Neutron scattering studies on the 1T 2 phase of TaS 2 at room temperature reveal a strong Kohn anomaly in the longitudinal phonon mode propagating in the (100) direction. The anomaly occurs at a wavevector 0.27a* comparable to the radius of circles of diffuse intensity seen in electron diffraction patterns. The elasti…
Abstract Control of sustained limit‐cycle instability in crystal size distribution (CSD) was simulated for a class II (high yield) crystallizer equipped with a fines destruction system and product classifier. Control was simulated by proportional control of nuclei density using fines destruction rate as the manipulate…
Abstract For systems of differential equations of the form ẋ = f(x) or x = f(x, t ) , a periodic response may be identified by the requirement that x( kT ) = x(0) , where k = 1, 2, … and T is the period, x(0) = x 0 being the initial‐condition vector. We describe a gradient method for finding this x 0 vector by minimiz…
The low-temperature diffusion of nickel through gold has been evaluated using Auger electron spectroscopy. Samples used were printed-wiring-board fingers having a nickel ’’diffusion barrier’’ plated between the copper substrate and the cobalt-hardened gold contact surface. A coefficient was determined for diffusion vi…
Résumé. — On a étudié les effets de taille dans des particules d'or (102 à 105 atomes/particules) préparées dans une matrice de verre. Des mesures d'absorption à 300 et 1,5 K dans le domaine spectral allant de 0,5 à 4,2 eV ont mis en évidence trois effets lorsque la taille des particules diminue: (i)…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPoisoning titration technique for determining the number of active centers in a supported platinum catalystL. Gonzalez-Tejuca, K. Aika, S. Namba, and John TurkevichCite this: J. Phys. Chem. 1977, 81, 14, 1399–1406Publication Date (Print):July 1, 1977Publication History Publi…
A theoretical investigation is presented of the order-parameter symmetries of all possible secondary and higher-order ferroic transitions, (nonmagnetic). These structural phase transitions, which are neither ferroelectric nor ferroelastic, involve the onset of a spontaneous macroscopic quantity represented by a polar…
Abstract The 1 H and 13 C spectra of fluorene, fluorenone, phenanthrene and their 4‐methyl and 4,5‐dimethyl derivatives have been examined. To complete the analyses for fluorenone and 4‐methylfluorenone, 1 H spectra were recorded at 270 MHz. The results from the 1 H spectra permitted unequivocal assignments for the pr…
Studies of the corrosion of OFHC copper in water contaminated with sulfide, oxygen, or sulfide plus oxygen have shown that the presence of either sulfide (48 to 1940 ppb) plus low oxygen (29 to 60 ppb) or oxygen alone (865 to 6950 ppb) leads to low corrosion rates. However, when both sulfide and oxygen are present in…
This paper discusses states in the gap in chalcogenide glasses. The model of “charged dangling bonds” put forward by Street and Mott (1975) and Mott, Davis and Street (1975) is reexamined in the light of new experimental evidence and theoretical concepts. It is shown that the model accounts both for the increase in th…
Configuration and activation energies and dipole tensors for single and multiple interstitials are calculated by computer simulation using three different potentials for Cu. The single interstitial forms a (100) dumb-bell. The di- and tri-interstitials consist of (100) dumb-bells on nearest-neighbour sites which are r…
Thin iron films (∼18 Å and 90% enriched in Fe57) were prepared on (001) Cu single-crystal substrates. The fcc structure was verified by electron microscopy. By Mössbauer spectroscopy it was found that antiferromagnetic ordering begins at around 80±10 K with hyperfine fields of about 16–20 kOe. Additional proof for the…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStructural and magnetic properties of di-.mu.-chloro-bis[bis(.eta.5-cyclopentadienyl)titanium(III)] and di-.mu.-bromo-bis[bis(.eta.5-methylcyclopentadienyl)titanium(III)]Rudolph. Jungst, Dennis. Sekutowski, Jimmy. Davis, Matthew. Luly, and Galen. StuckyCite this: Inorg. Chem…
When murine leukemia L1210 cells are exposed to certain porphyrins, in the presence of light, a rapid loss of cell viability occurs. We have examined structure-activity relationships, using a series of porphyrins, and have studied early effects of these agents, to elucidate their mode of action. In the system employed…
The present study reviews the sampling environments and chemical transformations of nitrogen oxides that may occur within probes and sample lines while sampling combustion products. Experimental data are presented for NOx transformations in silica and 316 stainless steel tubing when sampling simulated combustion produ…
Abstract The anisotropy of thermal conduction in a spherulite is calculated for a two‐phase model. The problem of the temperature distribution due to cooling of a spherulite suddenly heated at one point is solved. An analytical result is given and isothermal contours are calculated for wide ranges of thermal conductio…
Analysis of the detailed dynamic mechanical spectrum in the vicinity of the glass-transition temperature (T g ) of a series of polyamide textile fibers allows the prediction of their relative dyeabilities with a disperse dye, Celanthrene Fast Blue 2G, to an accuracy of about 1 K/S unit. The technique is sensitive enou…
Abstract The synthesis of novel photodegradable poly( o ‐nitrobenzaldehyde acetals) is described. The polymers were prepared by condensing o ‐nitrobenzaldehyde with a series of glycols. Polyesteracetals can also be prepared by first preparing the o ‐nitrobenzaldehyde glycol acetal or polyacetal prepolymer and subseque…
Polyvinyl chloride) obtained by intermittent polymerization in suspension with temperature programming, has been characterized from the point of view of morphological properties and of thermal stability. The data have been compared with the values of the morphological characteristics and thermal stability for the PVC…
Abstract 1 H and 13 C NMR spectra of 1,5‐cyclooctadiene oligomers were investigated and compared with those of 1,4‐polybutadiene. The oligomers were prepared with Rh 2 O 7 as catalyst and fractionated by vacuum distillation or gel‐permeation chromatography. It was found that each fraction consists of a mixture of ster…