Materials Literature
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Percolating networks based on interparticle tunneling conduction are shown to yield a logarithmic divergent piezoresistive response close to the critical point as long as the electrical conductivity becomes nonuniversal. At the same time, the piezoresistivity or, equivalently, the conductivity anisotropy exponent $λ$…
We develop a theory of the domain patterns in systems with competing short-range attractive interactions and long-range repulsive Coulomb interactions. We take an energetic approach, in which patterns are considered as critical points of a mean-field free energy functional. Close to the microphase separation transitio…
It is shown that diffraction of Bose-Einstein condensates on a helical light grating results in vortices in the condensate. Helical light gratings can be produced by light interference of a Gaussian laser beam with a helical one. Diffraction orders of the Bose-Einstein condensate contain vortices of corresponding topo…
We present new experimental results on the mechanical behavior of static granular assemblies confined in a vertical column. Our measurements confirm, for the first time, the universal Janssen's scaling for the stress saturation curve. We show consequently, in the context of isotropic elasticity, a relation between the…
We have calculated (ab initio) and measured (by spin-echo techniques) the anharmonic self-energy of phonons at the X-point of the Brillouin zone for isotopically pure germanium. The real part agrees with former, less accurate, high temperature data obtained by inelastic neutron scattering on natural germanium. For the…
The CdTe nanoparticles were prepared in aqueous solution using different mercaptocarboxylic acids such as 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA) as stabilizing agents following the synthetic route described in ref 9. The pH-dependent photoluminescence (PL) of MPA- and TGA-stabilized CdTe nanopartic…
An effort is made to define the notion of 'space factor,' an important parameter influencing the characteristics of all film high voltage power capacitors. It is shown that the space factor is only determined by the winding factor and press factor. A method for calculating the space factor at every point of an element…
The authors discuss innovative support techniques that are used to prevent misalignment of the tubes in the Tore Supra Phase III limiter head during plasma operations. Since thermal misalignment of the limiter with respect to the toroidal field will damage the limiter, all tubes in the tube bank must be maintained in…
Space-charge-formation characteristics in polyethylene, polypropylene, and their blends are discussed based on the results of DC conduction, thermal pulse current, and thermally stimulated current. Negative space charge is formed throughout the bulk of polypropylene, while positive space charge is formed in polyethyle…
Describes the application of a neural network algorithm to the perception of partial discharge patterns. The aim of this preliminary research is to see if the neural network is able to discriminate the tree initiation from the needle-shaped void gap. A needle-shaped void sample was made from epoxy resin to generate an…
The authors describe the natural contamination test results of six types of insulators exposed in the southern suburbs of Beijing. The station stands near the eastern terminal of a DC transmission line. It is also located in a smooth terrain, a typical farming area on the North China Plain. The maximum annual equivale…
The resistivity of high-purity copper was measured by a method that estimates resistivity by using the difference in the impedance of a circular multilayer solenoid coil with a cylindrical copper core and an identical coil without a copper core (SRPM method). It was confirmed that an exact measurement of the resistivi…
The NOVICE code is used by a number of government and aerospace organizations for radiation analysis of space systems. Generality of three dimensional modeling, with graphics output, is a major code capability. Major analysis methods are ray-trace/sectoring for rapid engineering design and Monte Carlo for design verif…
The history of electrical insulation from its origins to the present is briefly reviewed. In the 1800s the development of electrical apparatus made necessary the use of a variety of insulating materials to meet increasingly demanding needs. Up to about 1925 only naturally occurring products such as asphalt, rubber, mi…
It is pointed out that reliable HVDC insulation design has to take into account the fact that electric field distributions are different from AC distributions due to resistivities of the materials. Additionally, polarity reversals and transients result in field distributions different from steady state AC and DC field…
Abstract Liquid–liquid thermally induced phase separation of the polymer‐diluent system of poly(ethylene‐ co ‐vinyl alcohol) (EVOH)‐glycerol was examined under light scattering. For EVOH with an ethylene content of 38 mol % (EVOH38), maxima of the scattered light intensity were observed that indicated that phase separ…
In order to synthesize a peripherally rigid dendritic donor-acceptor dyad for energy transfer studies, a tritolan dendron based on a tetraphenylmethane scaffold was prepared from New Fuchsin. The dendron showed a small degree of homoconjugation but a large hypochromic effect. Coupling of two such dendrons with an anth…
A mechanism of degradation in polymeric insulation at fields lower than required for hot-electron transport is shown. Cable grade low-density polyethylene was aged under divergent and uniform fields, using needle-plane and dimple-plane geometries, respectively. It is shown that, at points of electric stress enhancemen…
To overcome the viewing-angle dependence of TN (twisted nematic) cells, the author has investigated two-domain TN (TDTN) and two-domain tilted homeotropic (TDTH) cells with optical compensation for active matrix applications. The simulated and experimental results for TDTN show a large viewing zone of +or-40 degrees i…
Compressed SF/sub 6/ gas is the main high-voltage insulation medium in gas insulated equipment. Recent progress in studies of high-voltage breakdown in uniform, quasi-uniform, and nonuniform field systems is described. This includes time lags to breakdown, the effect of particle contamination, and the flashover of ins…