Materials Literature
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We present the conditions in which a toroidal type, line frequency, power transformer can yield reduced stray magnetic field, reduced weight and size, and improved efficiency over an E-I laminate transformer in single phase linear power supplies. These benefits must be considered in relation to the disadvantages of sl…
The time stability of the surface potential of PTFE and silicon dioxide electrets at room temperature are similar: after an initial small decay the potential is practically constant during a time interval that decreases as humidity increases and then drastically drops. The time stability of the surface is correlated w…
The development of ferroelectric memory devices requires an understanding of the fatigue properties of ferroelectric thin films. PZT thin films by sol-gel method on Pt/Ti with residual polarization reduced by continuous polarization reversal about 10/sup 8/ cycles. In this paper, we regard Ir, IrO/sub 2/ and these lay…
We demonstrate a novel solid-state three-dimensional display using rare earth doped heavy metal fluoride glass as the active medium. In this device, two laser beams intersect inside a bulk glass at room temperature to address a pixel in three-dimensional space. The two-step resonant upconversion process requires two d…
Undoped barium titanate ceramics exhibiting a distinct positive temperature coefficient of resistivity (PTCR) effect have been produced by sintering high-purity barium titanate powder compacts in the temperature range 1300-1400/spl deg/C in air. The formation of core-shell type duplex microstructures in the materials…
The influence of /spl gamma/-ray irradiation on the phase transition temperature in (NH/sub 2/(C/sub 2/H/sub 5/)/sub 2/)/sub 2/CuCl/sub 4/ crystals was investigated. It has been ascertained that irradiation at room temperature leads to increase of transition temperature T/sub 1/. Contrary to this, irradiation just bel…
In this work, a neural network algorithm using the standardization method was developed to discriminate phase-shifted partial discharge (PD) patterns. Previous efforts to recognize PD patterns have been performed by applying the neural network to the /spl phi/-q-n pattern, which is composed of phase angle /spl phi/, d…
This paper describes monitoring of SOF/sub 2/ and SO/sub 2/F/sub 2/ in SF/sub 6/ insulated switchgear as indicators of the need to perform maintenance. The paper describes the results of routine monitoring for these byproducts in 131 sections of bus and 25 breakers over a period of three years. It describes an inciden…
The ferroelectric imprint is measured on thin-film PLZT capacitors with lanthanum strontium cobalt oxide top and bottom electrodes. The data show a significant amount of imprint with a combined elevated temperature and alternating (unipolar) voltage stress. No imprint was observed on samples that were temperature stre…
The leakage resistance of transmission line insulators suspended along the coast decreases with the accumulation of sea-salt blown from the sea, particularly when the relative humidity is high and the shed surface is slightly wet with rain or wet snow. In order to measure, automatically, by a leakage resistance data a…
Presents a study of the effects of coating thickness, various coating substrates and adding extra silicone fluid in RTV liquid on the electrical performance of RTV coatings. The leakage current and time to failure were monitored as a function of time of exposure to combined electrical stress and salt-fog in order to d…
In 1921 Joseph Valasek recognized for the first time ferroelectric properties in a crystal, namely in Rochelle salt. In this lecture we review the story of this discovery, of Valasek's origin and career.
The effects of acetophenone (AP) and cumylalcohol (CA) on the tan/spl delta/ of low density polyethylene (LDPE) were investigated in detail taking the temperature range of 25 to 100/spl deg/C and electrical stress range of 5 to 40 kV/mm. The tan/spl delta/ of LDPEs to which AP and CA (reagent special grade) and these…
In HVDC application, the interdisc winding insulation of a converter transformer is subjected to superimposed AC and DC voltages. Therefore, a knowledge of the behaviour of such an insulation system subjected to AC, DC and superimposed AC and DC voltages is essential. In order to simulate similar conditions in the int…
A new actuator for a robotic hand, composed of two NiTi shape memory alloy (SMA) springs, is studied. First, the properties of NiTi SMA springs, including load-displacement dependences at various temperatures, resistance-temperature dependence, and recovery-temperature dependence are tested and analyzed. It is found t…
Abstract Optical absorption and fluorescence emission spectra of 1,5‐diaminoanthraquinone (1,5‐DAAQ) in different solvents and the surface‐enhanced Raman scattering (SERS) spectrum of 1,5‐DAAQ in silver sol were investigated. Optical absorption and fluorescence emission studies revealed that the internal and external…
This paper describes the principle of the pulsed electroacoustic method (PEA) for space charge profile measurement in lossy and/or dispersive media. The method comprises the following aspects: analyze the principle of the PEA method in lossy and/or dispersive media; estimate the attenuation and dispersion factors in l…
In this paper the relation between successive partial discharges in insulating materials at DC voltage is discussed. Based on a few assumptions a DC voltage model, based on an RC-circuit, is presented and experimentally verified. Measurements of partial discharges have been made on samples containing air filled voids.…
The theoretical analysis of carrier scattering mechanisms in electronic lead chalcogenide crystals was carried out. The calculation of carrier mobility in wide temperature (4.2300 ) and concentration (10 16 10 20 m 3 ) ranges is carried out from the viewpoint of interaction of conductivity electrons with deformation p…
High permeability magnetic films used for shielding or absorption of electromagnetic interference (EMI) are commonly built in a multilayer stack to maximize the permeability by eliminating or reducing the number of domain walls. The choice of spacer material is driven by the fact that electrically insulating spacer ma…