Materials Literature
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Gas-insulated transmission lines (GIL) are a further development of the tubular conductor intended for long distances and are especially suitable for connecting conurbations to centers of power supply. They are also as "invisible" as ordinary power cables as well as having a number of other advantages. The first mixed…
The synthesis and characterization of three new unsymmetrical porphyrins and their Co(II) complexes are reported. The method that is used by synthesizing the porphyrins has not previously been reported. Structural assignment of the porphyrins and their Co(II) complexes is based on the elemental analysis, UV-Vis, IR, a…
Abstract Surface‐induced layering of fluorinated and protonated segments in thin films of a main‐chain liquid‐crystalline polymer, consisting of α‐methylstilbene, bridged by a fluorinated group was revealed by neutron reflectometry. The layering was driven by the difference in surface energy of the fluorinated and pro…
The image charge as measured with a guarded needle apparatus continues to increase for a time as the voltage drops after reaching its peak value, before leveling off to a relatively constant value. The increase of apparent charge beyond the peak voltage is the result of charge spreading in the dielectric even as the v…
Lead magnesium niobate (PMN) thin films have been grown on quartz/Cr/Au substrates from a single target source by rf magnetron sputtering at room temperature. Sputtering parameters and the post-annealing temperature have been optimized to obtain phase pure PMN films. Grain sizes, obtained from atomic force microscopy…
This paper presents the first results of a procedure which allows the determination of the threshold for space charge build-up in polymeric insulation subjected to ac electrical field. Thresholds for space charge accumulation under dc were determined by observing insulation until space charge appeared steadily. In ac…
Thermal interface materials (TIMs) are commonly used to reduce the thermal resistance between an electronic device and its cooling solution. The thermal performance of a TIM is very sensitive to its bond line thickness, and hence, the warpage profiles of the mating surfaces. The contact surfaces are usually never perf…
A novel approach for the analysis of millimeter-wave radiometer calibration target performance is presented. Analysis of wedge-profile targets is facilitated by performing both an electromagnetic and thermal analysis of the target. The scattered, transmitted, and internal fields of the wedge target, illuminated in the…
The measuring circuit for measuring Partial Discharges (PDs) does not differ when using AC or DC voltage. What differs is the analysis of the measured data. First, because there is no phase resolved information. Secondly, because of the much lower repetition rates. In addition, AC and DC high voltage applications tend…
Abstract A thermoplastic olefin blend consisting of isotactic polypropylene (PP) and an ethylene‐butene copolymer (EBR) impact modifier (25 wt % EBR) was subjected to a short, high‐shear pulse within the flow channel of a pressure‐driven microextruder following low‐shear channel filling from a reservoir of the melt. T…
Reaction of the inversely polarized phosphaalkene HP=C(NMe2)2 (1) with [AuCl(PPh3)] (2a) in a molar ratio of 2:1 in THF led to the formation of complex [Au{HP=C(NMe2)2}2]Cl (3) as a pale yellow solid. In contrast to this, treatment of 2a with two molar equivalents of tBuP=C(NMe2)2 (4) afforded a mixture of [Au{P(tBu)=…
Use of self-assembled Ge/Si(100) quantum dots (QDs) grown from pure isotope Ge70 and Ge76 sources provides a unique possibility to experimentally deconvolute contributions from Ge QDs and Si substrate into the Raman spectrum. We demonstrate that raw Raman spectra of Ge/Si(100) QDs are dominated by the Si substrate. We…
Two novel metallomacrocycles made up of difunctional 4,4′-diaminodiphenylmethane (DADPM) or 4,4′-diaminodiphenyl ether (DADPE) and cubane-like Cu4I4 cluster units have been prepared by the reaction of CuI and DADPM or DADPE in MeCN/H2O. The X-ray crystal structural analyses show that the topology of the cubane-like Cu…
Principles and techniques of three ASTM test methods of measuring thermal conductivity and thermal impedance of thin thermal interfaces are discussed. Although some measurement limitations exist in these ASTM methods, they provide an excellent starting point for the development of thermal property test protocols. The…
This paper discusses the results of partial discharge measurements in XLPE medium voltage power cables using oscillating test voltages. Based on laboratory and on-site tests the usefulness of this PD measuring technique for practical applications is presented. In particular, the sensitivity and the reproducibility of…
Characterization of the electrical, chemical, and microstructural properties of high voltage cables was the first step of the European project "ARTEMIS", which has the aim of investigating degradation processes and constructing aging models for the diagnosis of cross-linked polyethylene (XLPE) cables. Cables produced…
Si 4 clusters are soft-landed on an inert Van-der-Waals surface and the island formation is studied using x-ray and ultraviolet photoelectron spectroscopy. The experimental data indicate that the clusters do not fuse to Si islands but survive as individuals. The potential-energy surface of two Si clusters is calculate…
Although polymer insulators show excellent insulation characteristics, especially under contaminated conditions due to hydrophobicity on their surface, it is reported that corona discharges generated at high electric field portions such as energized end of a 500-kV polymer insulator, damaged the surface of its sheath.…
Partial discharges (PDs) are a major source of insulation failure in power transformers. Techniques for locating a PD source are of major importance in both the maintenance and repair of a transformer. A technique is described for locating a PD in a distribution power transformer. To study the propagation characterist…
A multistep procedure for the preparation of palladium-containing zeolite beta spheres using anion-exchange resin beads as shape-directing macrotemplates is presented. In a first step, resin beads are hydrothermally treated with zeolite beta synthesis solutions, and as a result resin−zeolite beta composite particles a…