Materials Literature
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Chalcogenide is a proven phase change material used in re-writeable CDs and DVDs. This material changes phases, reversibly and quickly, between an amorphous state that is dull in appearance and electrically high in resistance, and a polycrystalline state that is highly reflective and low in resistance. The application…
Presents new experimental data for single-wall carbon nanotube based field-effect transistors (CNFETs). New metal-nanotube contacts are shown to improve the performance of the CNFETs over previously reported values. Assuming conventional scaling, the improved device performance suggests that CNFETs may be competitive…
We compared plasma charging damage in single and dual damascene copper wafers with that in classical aluminum back-end-of-line (BEOL) wafers at different antenna levels. In contrast to earlier publications, this comparison is not straightforwardly in favor of the damascene BEOL, but rather depends on the process modul…
In this article, the changes of capacitance C and dielectric dissipation factor tan /spl delta/ of a non-penetrated water-treed XLPE sheet sample with voltage stress are discussed based upon the channel dynamism model. It has been found that the increase in tan /spl delta/ with high voltage stress is caused by the gro…
Industry has been exposed to partial discharge technology, related to generators, for many years. A switchgear manufacturer has invested in the advancement of partial discharge technologies related to the on-line analysis of insulation systems for MV switchgear. Partial discharge testing has been completed on both new…
This paper presents an analysis of power losses in gapless laminated iron cores at high frequencies. First, the magnetic field intensity is found. Next, the eddy current density is determined. Finally, expressions for the power loss density and the power loss per unit volume of an iron core are derived.
This paper presents a system to monitor the surface current over transmission line insulators. This gives an early warning for flashover when this current reaches a certain criteria. This ensures the continuity of the supply and minimum risk of line to ground fault occurrence. The system does not need any contact with…
Acoustic characteristics in the new cable PEA system have been analysed and it has been confirmed theoretically that the new system can provide the same sensitivity and resolution as the curved electrode system. The new system offers several advantages such as easy assembling sample, intimate contacts at the interface…
Epoxy resin is widely used as an insulation material in many electrical apparatuses because of its excellent electrical and manufactural characteristics. It is usually mixed with filler to improve mechanical and thermal characteristics. In order to quantitatively clarify the effect of fillers on the treeing phenomenon…
The purpose of the work presented here is to characterise polymeric HVDC cable insulation consisting of lapped thin film polypropylene with respect to DC current conduction and partial discharge activity in air filled butt gaps. The PD activity was found to strongly increase with increasing temperature and applied ele…
Abstract 3‐Chlorothiophene (CT) was electrochemically polymerized in mixed electrolytes of a boron trifluoride diethyl etherate solution containing 0–20% (by volume) sulfuric acid. The oxidation potentials of the monomer in these media were measured to be only 1.06–1.31 V (vs Ag/AgCl). These values were much lower tha…
We present a theoretical study of bond-length and angle variations in relaxed, epitaxially strained, and amorphous ${\mathrm{Si}}_{1\ensuremath{-}x}{\mathrm{Ge}}_{x}$ alloys. Our approach is based on Monte Carlo simulations, within the semigrand-canonical ensemble utilizing Ising-like identity flips, and in conjuction…
The PEA (pulsed electro-acoustic) and PWP (pressure wave propagation) methods are widely used effective techniques for measurement of space charge distribution in dielectric materials. Since these techniques are using pressure waves as a detecting signal, however, it is inevitable to be affected by an attenuation effe…
We study the coarsening dynamics of two- and three-dimensional biaxial nematic liquid crystals, using Langevin dynamics. Unlike previous work, we use a model with no a priori relationship among the three elastic constants associated with director deformations. Biaxial nematics possess four topologically distinct class…
The paper presents a method to determine the effects due to the punching process on soft magnetic materials used in the electrical machines. The proposed methodology, is based on a full experimental approach. Four wound cores, having the same geometrical dimensions, have been assembled as the overlap of a different nu…
The technique of crystal truncation rod (CTR) diffraction is widely used for studying the structure of crystalline surfaces and interfaces. The theory and experimental details of the technique are well established; however, published methods for structure-factor calculations are typically based on a simple surface cel…
Underground cable accessories used in medium voltage cable systems need a highly reliable stress control system in order to maintain and control the insulation level which is designed for estimated life times longer than 30 years of service. The term "electrical stress control" refers to the cable termination function…
The electric field in a dielectric changes from capacitive grading immediately after the voltage application to, resistive grading under steady state conditions. In the case of a polymeric dielectric, the conductivity is known to be strongly dependent on both the electric field and the temperature, characterized by an…
On site partial discharge (PD) methods have become successful tools to diagnose and monitor cable circuits. This paper describes the background of these methods, some fundamentals and challenges. The first section gives a brief introduction to and definition of the 0.1 Hz or very low frequency (VLF) PD methods. The ne…
We consider a model mixture of hard colloidal spheres and nonadsorbing polymer chains in a theta solvent. The polymer component is modelled as a polydisperse mixture of effective spheres, mutually noninteracting but excluded from the colloids, with radii that are free to adjust to allow for colloid-induced compression…