Materials Literature
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Abstract The mechanisms of aromatic nucleophilic substitutions are briefly reviewed with emphasis on those which have been used for the synthesis of aromatic polyethers and aromatic polythioethers, i.e. the S N Ar, the S RN 1, and a variant of S RN 1 (the S RN 1′) mechanisms. The synthesis of poly(ether ketone)s by th…
<div class="htmlview paragraph">Strain rate sensitivity is an important material property in the formability of sheet metal. In this study, strain rate sensitivity is evaluated for several different grades of steel. Strain rate sensitivity varies from 0.01 to 0.022 for the steels tested. It was found that formab…
The nonlinear optical properties of a perfectly polarized KIO 3 single crystal were investigated. The principal refractive indices and nonlinear optical coefficients have been measured. The results are as follows: n 1 = 1.6967, n 2 = 1.8329, n 3 = 1.8358 for 0.5893 μm; d 31 = 1.2| d 31 (LiIO 3 )|, d 32 = 1.8| d 31 (Li…
The Raman spectrum of a ${\mathrm{KNO}}_{3}$ single crystal was measured at both room and liquid-nitrogen temperatures. Lattice-dynamical calculations, based on the rigid-ion approximation and empirical potentials, were performed. The possibility of a phase transition at 217 K was investigated by measuring the tempera…
Single-beam overwrite performance of 5.25 inch diam. In 3 SbTe 2 phase-change optical disks was examined at a constant angular velocity (CAV) of 1800rpm (υ=5-11 m/s). We obtained overwrite with a new erase mode and achieved a large erasability of more than 35 dB and a carrier-to-noise ratio ( C / N ) of more than 50 d…
We consider a tiling of the plane generated by a substitution, the largest eigen-value of which is not a Pisot number. This property leads to unbounded fluctuations of the density in perpendicular space and to the absence of Bragg peaks in the diffraction spectrum of the structure. This spectrum is computed by means o…
Abstract The <0.5- μ m fraction of 120 samples from a lithologically complex Permian sedimentary sequence, underlying dolerite intrusive sheets, has been characterized by means of X-ray diffraction to establish I/S compositions as a function of temperature, lithology and time duration. Illitization has been active…
The local environment around copper in the Cu 2 O·Al 2 O 3 ·4SiO 3 and CuO·Al 2 O 3 ·4SiO 2 glasses was investigated using the extended X‐ray absorption fine structure (EXAFS) technique. It has been found that each Cu(I) in the former glass is coordinated to two oxygens through covalent Cu(I)‐O bonds. This is the prim…
Depolarized Rayleigh and polarized Rayleigh–Brillouin scattering are employed to examine the mobility of toluene in solutions of poly(methyl methacrylate) (PMMA) and for PMMA concentrations: 0≤cPMMA≤1. The depolarized Rayleigh measurements were performed in the temperature range 20–120 °C with several interferometer s…
Abstract The benzene solutions of a mesogenic tetraphenylporphyrin, 5,10,15,20-Tetrakis(4-n-pentadecylphenyl)porphyrin, and its metal complexes (metal: Co, Ni, Cu, Zn, and V = O) were investigated to determine the 3rd-order nonlinear optical susceptibilities χ(3) by nanosecond degenerate four-wave mixing (DFWM) at 532…
Abstract Nitridophthalocynaninatochrom(V), [CrNPc2‐], wird durch die Oxydation von [Cr(OH) 2 Pc(2‐)]‐ mit Chor in Gegenwart von überschüssigem Ammoniak als paramagnetisches (μ eff = 1,99 B. M.), feinkristallines blaues Pulver dargestellt. Obwohl Chemisch sehr resistent, reagiert es wie auch das isostrukturelle Nitrido…
Comparative neutron diffraction experiments on AgPO3 and AgI-AgPO3 glasses reveal large changes in the intermediate-range ordering as the dopant salt is introduced, whereas the short-range ordering of the host matrix is unchanged by the salt. The observations indicate a microscopically unaffected host network and spac…
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:…