Materials Literature
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We report initial NMR studies of continuous flow laser-polarized xenon gas, both in unrestricted tubing, and in a model porous media. The study uses Pulsed Gradient Spin Echo-based techniques in the gas-phase, with the aim of obtaining more sophisticated information than just translational self-diffusion coefficients.…
We report a new method for the purification of HiPCO single-wall carbon nanotubes (SWNT), which consists of the following sequence: (a) organic functionalization of the as-produced nanotubes (pristine tubes, p-SWNT), (b) purification of the soluble functionalized nanotubes (f-SWNT), (c) removal of the functional group…
Gold nanorods have been synthesized by photochemically reducing gold ions within a micellar solution. The aspect ratio of the rods can be controlled with the addition of silver ions. This process reported here is highly promising for producing uniform nanorods, and more importantly it will be useful in resolving the g…
This paper introduces the curing curve analysis, the polymerizing reaction kinetic parameter calculation, and the determination of the relationship between the curing degree and the curing temperature and curing time. For the materials used as the ground insulation of the generator winding, measurements have been made…
The dynamic mechanical properties of epoxy/mica glass-fiber reinforced composites were studied at different aging stages under electrical-thermal stresses and thermal-mechanical stresses. A new method was proposed to calculate the apparent activation energy of glass transition (AAEGT) of epoxy/mica based on dynamic me…
Capacitors made of metallized films of plastics suffer partial discharge named self-healing. This disruptive phenomenon is described as the spontaneous extinction of an electrical arc due to the destruction of the electrodes during the process. In this paper we modelize self-healing by a cylindrical arc that strikes a…
An experiment was performed to clarify how the carrier mobility is influenced by the existence of acetophenone in polyethylene. One side of a polyethylene film, 0.1-mm thick, was soaked with acetophenone. Time-dependent charge distribution was monitored by the pulsed-electroacoustic method, when a "carrier excitation…
The nucleation and growth of Si and Ge clusters/crystallites on SiN x films, which act as relative inert substrates, proceed in a quite complicated manner compared with conventional epitaxial processes. We examine the size dependence of the shape, surface structures and orientation of nano-scale clusters/crystallites.…
Inductors for filtering devices are widely employed in power electronics applications in order to reduce voltage and current harmonics caused by switching converters. The use of ferrite-core inductors is limited to small power applications, whereas air-core and laminated iron-core inductors are employed in the medium-…
This paper investigates the AC electrical characteristics of zinc oxide filled epoxy resin at high electrical fields. The AC conductivity of two filler concentrations, 10% and 20% was measured and compared with the conductivity of unfilled resin. In addition, zinc oxide powder was compressed into solid samples which w…
A digital integrated system is developed to record partial discharge (PD) pulses and to recognize their patterns by waveforms. Special considerations on the experiment circuit are given to electromagnetic shielding, system bandwidth and pattern variety. Both typical laboratory models and simulation models of stator wi…
Time-lag of void discharges was measured in order to establish the physical model for the formation of partial discharge pattern under AC voltages. The measurement with step voltages, using CIGRE Method II electrode system, showed that the statistical distribution of the discharge time-lag depends on the applied volta…
The partial discharge (PD) measurement is a very well known possibility to assess the quality of an insulation system. The aim of the PD-diagnostic is the detection of destruction of electrical insulation as a result of electrical stress especially of PD during operation. Therefore many methods of PD-measurement techn…
The extensive advent of optical communication networks requires new generations of large integrated optical switch matrices able to route information and data streams. We report a novel low cost bistable coupled-waveguide switch based on voltage controlled reorientation of a surface stabilised ferroelectric liquid cry…
Partial discharge detection using optical technique is studied with a view toward its application to explosion-proof motors and power transformers. For this purpose, an optical partial discharge measurement system has been established and some fundamental investigations such as attenuation of light intensity in differ…
Silicone rubber is a new insulating material for HV outdoor insulators. In order to know the long term of its performance we investigated the aging of the material under a natural tropical environment. This paper reports the investigation results on surface degradation of silicone rubber with different filler content…
In this paper a novel high voltage (HV) system for testing five specimens in parallel under different combinations of voltage and temperature is presented. When partial discharges (PD) are present, the system allows under a computer supervision the cyclic acquisition of PD signals coming out from each specimen by mean…
Considering various contaminated environments in the field, research on the hydrophobicity transfer properties of different pollutants is necessary for the proper selection and maintenance of polymeric insulators. In the paper, hydrophobicity of SR polluted by several kinds of pollutants such as kieselguhr, kaolin, To…
Vibro-acoustic diagnostic of on-load tap changers (OLTC) offer numerous advantages: applicable online, sensitive to mechanical as well as electrical malfunctions, retrofitable to old equipment, simple and low-cost. Over the last few years, Hydro-Quebec has spent considerable efforts in the development of a reliable ac…
To investigate the reliability of the insulation of equipment having vacuum incorporated as an insulation medium, a study was carried out to clarify breakdown probability distributions in the vacuum gap. Experiments were carried out to investigate the effects of test methods, electrode area, and electrode materials on…