Materials Literature
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An electronic technique which greatly increases the apparent permeability of a magnetic core of a current transformer, without a galvanic connection to either of the usual primary or secondary winding circuits, is described. The number of turns and the turns ratio can be selected independently as desired. Means are av…
When the short-time electric strength (E/sub st/) of low loss polymers is determined in accordance with IEC 243, breakdown is usually caused by 'surface discharges'. Unless there are gross isolated defects, E/sub st/ is more dependent on the thickness d than on the area of the samples. E/sub st/ is affected by the per…
Abstract Possibilities and thermal preconditions of the preparation of filled β‐PP composites were studied. Two types of mineral fillers (chalk and talc) were found considerably different. Chalk, as a weak α‐nucleating agent, exerts minimum influence on the rate of crystallization, on the polymorphic composition, and…
We have calculated for the first time the contribution to the shear viscosity η of a dilute suspension of hard spheres from the full hydrodynamic interactions involving three spheres. Using the multiple scattering theory, we find the third order coefficient k3 in η=η0(1+k1Φ+k2Φ2+k3Φ3 +⋅⋅⋅) to be 6.40 for a suspension…
Different models for linear transformers are discussed relative to their use in circuit simulation. These models include: the reluctance model, the permeance model, the inductance matrix model, the T-model and the reduced T-model. Equations relating the parameter values of the models are derived for the two- and three…
Abstract Aqueous gels of unaltered (oxidized) and chemically reduced ferruginous smectite (SWa-1 from the Source Clays Repository of The Clay Minerals Society) were characterized by transmission electron microscopy, electron diffraction, and energy-dispersive X-ray fluorescence to establish details regarding their tex…
Abstract The potential role of phosphoproteins in the regulation of carbonate biomineralization is examined by comparing the EDTA‐soluble matrix (SM) of bivalve shells from representatives of eight superfamilies having various aragonitic and calcitic microstructures. In each case the SM is separated into two fractions…
High-resolution powder diffraction coupled with the total-pattern-fitting technique revealed unusual and hitherto unreported diffraction effects for samples of copper(II) oxide. Data were obtained with a conventional diffractometer and strictly monochromatic Cu Kα1 radiation and also with the Daresbury Laboratory sync…
Cristallisation a 294 K dans Pca2 1 avec a=12,924, b=14,034, c=15,364 A, Z=4; affinement jusqu'a R=0,032. A T=349 K, cristallisation dans Pcab avec a=13,003, b=14,038, c=15,450 A, Z=4; affinement jusqu'a R=0,044. Dans la phase haute temperature, les anions sont des bioctaedres centrosymetriques et trois des cinq catio…
The average structure of mullite with approximate composition SiOr.2AlrO, has been refined using single-crystal neutron ditrraction data. A split-site model for both tetrahedral and O positions was refined in order to reflect the local structural variation arising from both O-vacancy and Al-Si ordering. The resulting…
Modeling of shape-memory alloys represents a multiscale problem due to the occurrence of a martensite/austenite phase transformation and a microstructure in the deformation gradient typical for a martensitic phase. Inspired by relaxation in a static situation, a limit passage between two modeling scales, called micro-…
We present a model to explain the peak observed in the Si etch rate vs. molarity for several alkali‐hydroxide solutions. This model requires both free water molecules ( H 2 O ) f and hydroxyl ions (OH − ) to accomplish etching. As the molarity increases, the OH − concentration increases, while hydration effects steadi…
Abstract The evolution of crystallinity of neat PPS and of the carbon fiber reinforced polymer under different processing conditions is studied. Crystallization from the amorphous state at low temperatures (cold crystallization), crystallization from the melt during cooling, and crystal melting processes are analyzed…
The crystal structure of antiferroelectric Pb(Yb 1/2 Nb 1/2 )O 3 has been characterized. Both X-ray diffraction and transmission electron diffraction show two sets of superlattice reflections originating respectively from the B-site atom ordering and the antiparallel lead-atom displacements which suffer within the ort…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPicosecond laser photolysis studies on the photorepair of pyrimidine dimers by DNA photolyase. 1. Laser photolysis of photolyase-2-deoxyuridine dinucleotide photodimer complexTadashi Okamura, Aziz Sancar, Paul F. Heelis, Tadhg P. Begley, Yoshinori Hirata, and Noboru MatagaCi…
Pure non-stoichiometric amorphous vanadium pentoxide (V2O5) has been made by splat cooling from the melt. The vanadium coordination is analysed by infrared spectroscopy, X-ray absorption at the vanadium K edge (X-ray absorption near-edge structure and extended X-ray absorption fine structure) and 51V solid-state nucle…
Ferroelastic domain switching is one of the possible toughening mechanisms in ceramic materials. Microstructural evidence of domain reorientation (switching) in polydomain tetragonal zirconia single crystals is observed upon the application of a unidirectional compressive stress at 1000° and 1400°C. Dark‐field imaging…
We report a computer-simulation study of the stability of the columnar phase in a system of parallel spherocylinders with aspect ratios L/D=5 and \ensuremath{\infty}. It is found that the range of stability of the columnar phase is strongly dependent upon the system size. In particular, for particles with an aspect ra…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPerimeter model and magnetic circular dichroism of porphyrin analogsJacek Waluk and Josef MichlCite this: J. Org. Chem. 1991, 56, 8, 2729–2735Publication Date (Print):April 1, 1991Publication History Published online1 May 2002Published inissue 1 April 1991https://pubs.acs.or…
Conformational disorder in crystal structures of ribonuclease-A and crambin is studied by including two independent structures in least-squares optimizations against X-ray data. The optimizations are carried out by X-ray restrained molecular dynamics (simulated annealing refinement) and by conventional least-squares o…