Materials Literature
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There are several polymers being used as extruded insulation in high-voltage power cables from 5 kV up to 500 kV. They include low density polyethylene (LDPE), crosslinked polyethylene (XLPE), tree-retardant crosslinked polyethylene (TRXLPE) and different formulations of ethylene propylene rubber (EPR). The ageing mec…
Shape memory alloy (SMA) based actuators have a number of attributes which make them useful for robotic applications. Unfortunately their response is relatively slow being limited by the speed with which the SMA can be heated and cooled. This paper describes two novel developments of the basic SMA actuator which impro…
An increasingly urgent topic for the realization of densely packed (mixed signal) integrated circuits is prevention of cross-talk via the substrate. The paper proposes a boundary element method (BEM) for calculating an admittance matrix for the substrate in order to analyze the parasitic coupling during layout verific…
In a nematic liquid-crystal cell, the molecules can be realigned by an ultrasonic wave, leading to a change in the optical transmission through the cell. We present a model for this acousto-optic effect, and show that the magnitude of this effect is controlled by a director-density coupling. We then measure the optica…
We present a quantitative evaluation of the influence of the electron transfer on the magnetic properties of mixed-valence polyoxometalates reduced by two electrons. For that purpose, we extract from valence-spectroscopy ab initio calculations on embedded fragments the value of the transfer integrals between W nearest…
New stereoregular cyclic polysilanols of the general formula [PhSi(O)OH]n (n = 6 and 12) have been selectively obtained in high yields by the reaction of cagelike oligophenylmetallasiloxanes with dilute solutions of hydrochloric acid at low temperatures. An alternative method was used to prepare cis-[PhSi(O)OH](4) fro…
The ${\mathrm{LaMn}}_{1\ensuremath{-}x}{\mathrm{Ga}}_{x}{\mathrm{O}}_{3}$ series $(x=0.05,$ $0.1,$ $0.15,$ $0.3,$ $0.4,$ $0.5,$ $0.6,$ $0.8,$ $0.9)$ was studied by means of ac magnetic susceptibility, magnetization, and neutron diffraction as a function of temperature. The crystal and magnetic structures have been ref…
As this paper shows, the magnetic coupling of the inductances of two hysteresis-controlled single-phase AC-to-DC boost power converters connected in parallel leads in connection with a delayed switching of the power transistors to a self-adjusting staggered switching of the partial systems. Thereby, a significant redu…
We have studied the structural properties of CdO in the rock-salt (sodium chloride), cinnabar, orthorhombic cmcm, cesium chloride, nickel arsenide, zinc blende, and wurtzite structures using first-principles total energy calculations. Rock-salt is the calculated ground state structure with $a=4.77\mathrm{\AA{}},$ ${B}…
With the aim of better understanding the electronic and structural factors which govern electron-transfer processes in porphyrins, the electrochemistry of 29 nickel(II) porphyrins has been examined in dichloromethane containing either 0.1 M tetra-n-butylammonium perchlorate (TBAP) or tetra-n-butylammonium hexafluoroph…
${\mathrm{NdBaCo}}_{2}{\mathrm{O}}_{5.47}$ cobaltite has been investigated using neutron and synchrotron powder diffraction. At ${T}_{\mathrm{MI}}\ensuremath{\sim}360\mathrm{K},$ the compound exhibits an associated metal-insulator and spin-state transition commonly observed in these systems. At ${T}_{N}\ensuremath{\si…
Abstract Polypropylene matrix composites reinforced with single‐walled carbon nanotubes (SWNTs) were produced with different nanotube concentrations. The characterization of these new materials was performed by differential scanning calorimetry and Raman and Fourier transform infrared spectroscopy to obtain informatio…
We present a new first-principles formalism for calculating forces for optically excited electronic states using the interacting Green's function approach with the GW-Bethe Salpeter Equation method. This advance allows for efficient computation of gradients of the excited-state Born-Oppenheimer energy, allowing for th…
Single crystals of nonlinear optical material l -arginine acetate (LAA) (C 6 H 14 N 4 O 2 ·CH 3 COOH), space group P 2 1, were successfully grown for the first time by the temperature-lowering method and also by the slow evaporation method at constant temperature (30 °C) from its aqueous solution with pH at 6 and dime…
The formation of patterned nanostructure in AgCo/Pt/MgO(001) thin film is simulated by a technique of combining molecular dynamics and phase-field theory. The dislocation (strain) network existing in Pt/MgO is used as a template whose pattern is transferred to AgCo phase in spinodal decomposition, resulting in regular…
We show that the rheological properties of dry granular materials, as well as foams and emulsions, are similar to typical thixotropic fluids: under a sufficiently strong shear the viscosity decreases in time, leading to a hysteresis in an up-and-down stress ramp. This leads to a viscosity bifurcation around a critical…
A new mechanism different from the spin accumulation picture is proposed for the current induced magnetization switching in magnetic tunnel junctions by taking into account the effect of the electron electron interaction. We found in tunnel structures the possibility of an enhanced spin switching effect that, when nor…
In a recent letter, J. P. Wright et al [Phys. Rev. Lett. 87,266401 (2001) and cond-mat/0111119] have investigated the crystal structure of magnetite below the Verwey transition temperature (TV) by means of X-ray and neutron powder diffraction. We show that the interpretation given by J. P. Wright et al. is unsupported…
The structural and electronic properties of a single pentacene molecule and a pentacene molecular crystal, an organic semiconductor, are examined by a first-principles method based on the generalized gradient approximation of density functional theory. Calculations were carried out for a triclinic unit cell containing…
Hybrids of silver particles of 1 to 2 nm in size with highly branched amphiphilically modified polyethyleneimines adhere effectively to polar substrates providing environmentally friendly antimicrobial coatings.