Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSynthesis and physical properties of amorphous poly(aryl ether isoquinoline)sRina Singh and Allan S. HayCite this: Macromolecules 1992, 25, 3, 1033–1040Publication Date (Print):February 1, 1992Publication History Published online1 May 2002Published inissue 1 February 1992htt…
Transition between two ferroelectric phases in the range of 85°C was observed when studying dielectric and semiconductive properties of Pb(Fe0.5Nb0.5)O3 crystals and ceramics. It was found that electron space-charge polarization plays the important part in formation of dielectric properties. The reasons of ϵ (T) anoma…
The anodic dissolution process of silicon in aqueous ammonium‐bifluoride solution during electrochemical carrier‐concentration profiling has been investigated for samples of various crystal orientation as well as dopant type and concentration. The effective dissolution valence and the surface roughness of the etched c…
The strength of a brittle material is determined by the extreme tail of its crack-size distribution. The Weibull ansatz of algebraic distributions has been widely used but is not derived from any physical mechanism, and recent results on randomly depleted networks exhibiting exponential distributions have called this…
Abstract High-resolution transmission electron microscopy has revealed spherical and hemispherical structures on the surface of partly hydrated volcanic and synthetic glasses. These structures contrast with the bulk of the glass in showing lattice-fringe images indicative of the early stages of crystallization. Heavy-…
A new method is described for preparing multilayered alloys by periodically interrupting electrodeposition of the less noble metal to permit electroless displacement of a portion of the electrodeposited material by the more noble component. Visibly smooth, nodule‐free Cu‐Ag alloys of controlled composition have been p…
Fluxes of 14 kinds of lanthanides across cellulose triacetate membranes were determined by using mixtures of o-nitrophenyl n-octyl ether and a series of polyoxyethylene n-alkyl ethers (POE ethers) as plasticizers, and hinokitiol as carrier. Effects of alkyl and polyoxyethylene (POE) chains of the POE ether on the flux…
Abstract The overall conductivity of the system AgCl/AgI is studied and distinct anomalies are found in the miscibility gap (Ag + ‐conductivity enhancement up to 1.5 orders of magnitude). An impedance spectroscopic investigation accompanied by studies of phase diagram and microstructure proposes two main conclusions:…
delta 5-3-Ketosteroid isomerase (KSI: EC 5.3.3.1) of Pseudomonas testosteroni catalyzes the isomerization of delta 5-3-ketosteroids to delta 4-3-ketosteroids by the stereospecific transfer of the steroid 4 beta-proton to the 6 beta-position, using Tyr-14 as a general acid and Asp-38 as a base. Ultraviolet resonance Ra…
We study the reflection \ensuremath{\Vert}${\mathit{r}}_{\mathit{N}}$\ensuremath{\Vert} of a plane wave (with wave number k>0) through a one-dimensional array of N \ensuremath{\delta}-function potentials with equal strengths v located on a Thue-Morse chain with distances ${\mathit{d}}_{1}$ and ${\mathit{d}}_{2}$. O…
The use of high amplitude focused ultrasound fields is widespread in medical diagnosis and therapy but there has been relatively little work published that compares experimental measurements with appropriate theory for such systems. In this paper, comparisons are made between the measured continuous-wave pressure fiel…
Tin‐doped indium oxide (ITO) layers show severe corrosion in alkaline solutions when they are in electrical contact with Al. This corrosion process is investigated by etching experiments, electrochemical measurements, and analytical techniques. It is shown that Al maintains ITO at a cathodic potential where it is redu…
In situ observations using interference contrast microscopy have been carried out in an electrochemical deposition system of a ${\mathrm{ZnSO}}_{4}$ solution film. Concentration oscillation around a growing dendrite tip, which is illustrated by local contrast oscillation, has been found to correspond to sidebranching…
Abstract Clay of apparent hydrothermal origin that fills amygdales in the Granby Basaltic Tuff (Lower Jurassic) of the Connecticut Valley was analyzed and found to consist of two exceptionally well-crystallized Fe-rich, trioctahedral 2:1 layer expandable phyllosilicates. Based on chemical and XRD analyses, the mineral…
The temperature dependence of the nucleation density of Chemical Vapor Deposition diamond was carefully investigated by ellipsometric monitoring. Substrates were pre-treated by rubbing with diamond powder and then by wiping off the residual powder until visually clean. Nucleation density was greater than 10 10 /cm 2 i…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRelative strength of 4d vs 5d .delta.-bonds: rotational barriers of isostructural molybdenum and tungsten porphyrin dimersJames P. Collman, J. Michael Garner, Robert T. Hembre, and Yunkyoung HaCite this: J. Am. Chem. Soc. 1992, 114, 4, 1292–1301Publication Date (Print):Febru…
Abstract The system studied in this work is a dilute solution of rod‐like molecules under simple shear flow and near a hard wall. The time evolution of the probability density function is described by a diffusion equation; particle trajectories that correspond to this equation are generated by stochastic methods. Seve…
Recently it has been suggested that thermal electronic properties of magnetic mixed valence systems have to be studied by using an effective Hamiltonian different from the Heisenberg one, so successful for localized electron systems. The object of this paper is to specify conditions of validity of both Hamiltonians. I…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTDissociation behavior of poly(fumaric acid) and poly(maleic acid). 3. Infrared and ultraviolet spectroscopySeigou Kawaguchi, Toshiaki Kitano, and Koichi ItoCite this: Macromolecules 1992, 25, 4, 1294–1299Publication Date (Print):February 1, 1992Publication History Published…
Dense α‐sialon materials were produced by hot isostatic pressing (HIP) and post‐hot isostatic pressing (post‐HIP) using compositions with the formula Y x (Si 12–4.5 x , Al 4.5 x )‐(O 1.5 x ,N 16–1.5 x ) with 0.1 ≤ x ≤ 0.9 and with the same compositions with extra additions of yttria and aluminum nitride. X‐ray diffrac…