Materials Literature
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Polycrystalline cerium hydroxysulfate powders have been prepared by soft solution processing using various basic solvents. The crystals prepared have varying morphologies, spherical and flaky, depending on the solvent used. The crystals obtained from distilled water–pyridine and aqueous ammonia solvent mixtures are sp…
Polyconjugated regular bithiophene-alt-thiophene-S,S-dioxide copolymers were produced by anodic coupling of variously 3,4-ethylenedioxy-substituted 2,5-bis(2-thienyl)thiophene-S,S-dioxide. The polymers were characterized by cyclic voltammetry, FTIR reflection-absorption and UV-vis spectroscopy, MALDI-TOF mass spectros…
This paper presents the variation of breakdown voltages experimentally obtained under high frequency high voltage stress on different insulating materials viz., PTFE, polypropylene and paper. An experimental facility using a vacuum tube oscillator circuit has been developed for the generation of high frequency high vo…
The aim of this work is to propose a new approach for the iron losses prediction, in soft magnetic materials with any voltage supply, starting from the knowledge of the iron losses with sinusoidal supply. The model is based on the separation of the loss contributions due to hysteresis, eddy currents and excess losses…
A new approach for experimental determination of stray capacitances in high frequency transformers is proposed in this paper. This approach identifies the stray capacitances of a two winding transformer by conducting open and short circuit tests on both windings within the range of normal operation frequencies and fit…
We have conducted detailed comparisons of the predictions of self-consistent mean-field (SCMF) theory with results of Monte Carlo simulations for bulk lamellar structures of symmetric diblock copolymers A−B in concentrated solutions. Large differences are found among the values of the Flory−Huggins parameter extracted…
This paper provides the failure analysis of three phase, dry type, silicone resin vacuum pressure encapsulated, 750/1000 kVA, AA/FA, 34.5 kV-480 Y/277 V, delta-wye, power transformer. Transient overvoltage switching surge propagation through the transformer winding and protection margin is discussed. An arbitrary sens…
After the local breakdown of the metallized film, the self-healing of the capacitor is influenced by several factors, including the capacitance of metallized capacitor, pressure, as well as the applied voltage. In this paper, they are investigated fundamentally in reference to their influence towards the insulation re…
A modified cable pulsed electro-acoustic (PEA) system using the plate outer electrode, which enables the technique to be applied to different cable sizes, is introduced to measure space charge distribution in extruded polymeric power cables. Some preliminary measurement results from cable samples are presented.
The complex [[Cu3(HpztBu)4(mu-pztBu)2(mu-F)2(mu 3-F)]2]F2 (HpztBu = 3[5]-tert-butylpyrazole) has a cyclic, C2v-symmetric hexacopper core. The two non-coordinated F- anions are encapsulated within cavities formed by three HpztBu ligands.
This paper describes the weight change of alumina trihydrate filled silicone rubbers during a water absorption process and the surface changes involved. The weight changes for some samples were particularly examined after being dipped in warm water (20/spl sim/80/spl deg/C). Worthwhile results are obtained as follows.…
The paper deals with the topic of a Gas Insulated Substation (GIS) optimized for HVDC. The electric field distribution of DC systems is mainly controlled by the conductivity k of the dielectric media. Surface charge accumulation leads to field distortion. In order to prevent this phenomenon on the spacer of such syste…
An assembly of Au nanoparticles is fabricated by the condensation of peptide bonds between L-lysine molecules attached to the surface of 13 nm Au nanoparticles. The formation of peptide bonds between the L-lysine molecules is confirmed by Raman spectra. It is found that L-lysine molecules are absorbed onto the Au coll…
This paper reports preliminary results of a study that deals with the effect of voltage imbalance and distortion upon the thermal aging of induction motor insulation. The study is based on a detailed three-dimensional modeling of heat transfer flow and the monitoring of the temperatures of hot spots. It has been learn…
Abstract The absorption edge in Mn K ‐edge X‐ray absorption spectra of manganese oxide compounds shows a shift of several electronvolts in going from MnO through LaMnO 3 to CaMnO 3 . On the other hand, in X‐ray photoelectron spectra much smaller shifts are observed. To identify the mechanisms that cause the observed c…
We have performed ab initio simulations to investigate the effect of carbon adatoms on the plastic deformation of carbon nanotubes. Under applied stress, the system spontaneously undergoes a Stone-Wales transformation catalyzed by the exchange of the adatom with a substrate atom. The unraveled mechanism reduces the ba…
We study the melt rheology and molecular weight distribution of four short chain branched hyperbranched polyesters with different molecular weights and containing branched monomers of various alkyl chain lengths n (2 → 4; n is the number of CH 2 groups in the alkyl chain). We find that the molecular weight distributio…
In the literature two intrinsic paramagnetic centers have been identified by EPR in pure zirconia: Zr 3+ ions, yielding an axial signal ( g ∥ = 1.958 and g ⊥ = 1.979) and electrons trapped in oxygen vacancies (V Ȯ ). In this study we investigated by quantitative-EPR pure and doped ZrO 2 heated in air and redox treated…
A study of the rheological properties of silica-filled nanolatex films by means of uniaxial strain experiments is presented. The samples are made by evaporating the aqueous solvent of mixtures of colloidal silica and colloidal nanolatex, followed by film formation. The reinforcement effect due to the introduction of h…
High-quality Co 2 P nanoparticles have been obtained from diphosphine-substituted molecular cobalt clusters anchored into an inorganic matrix. The synthesis was followed stepwise using a wide panel of analytic techniques. The required functionalization of an ordered mesoporous silica matrix of the type SBA-15 was achi…