This paper describes an application of ESCA analysis for semiconducting materials in XLPE power cables in terms of the oxygen ratio (defined as the ratio: integrated intensity of oxygen spectrum/integrated intensity of carbon spectrum). Analyzed materials were carbon blacks, an additive mixed into semiconducting materials and several semiconducting materials treated in various cross-linking conditions. It was found that the additive increases the exygen ratio of semiconducting materials as well as cross-linking treatment does. The more the oxygen ratio of the semiconducting materials increases, the less the averaged lamellar angle in XLPE insulation at the semiconducting interface decreases. The angle is though to be a parameter which concerns the hyper-structure of polymer insulation and the less angle value corresponds to the better state of the semiconducting interface in XLPE power cables.

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We investigated the electrostatic charging phenomena of polymer films used for the thermal control materials of spacecrafts by electron-beam irradiation simulating the hot plasma in space. Three kinds of polymer films, Teflon FEP (flurinated ethylene-propylene), Kapton PI (poly imide) and Mylar PET (poly ethylene telephthalate) of the thickness of 13-75μm, were tested under the irradiation conditions of the electron energy E lower than 50keV and the beam current density J_b lower than 1nA/cm². The surface potentials V_s of the films were obtained as functions of E and J_b at the constant irradiation time.
The obtained experimental results are as follows.
(1) V_s increases with increase of J_b. When V_s∞J_bⁿ is assumed, the n value is different during the films: n=1 for FEP film, n_??_0.5 for PI film and 0.5_??_n_??_0.8 for PET film.
(2) In V_s-E characteristics, V_s has the peak at some electron energy which is dependent on the material and the thickness.
These results were explained by an one-dimensional charging model in which one charge deposition layer is assumed to be formed in the bulk of the film and the volume resistivity and the secondary electron emission coefficient of the material are considered.

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The complex permeability of ferrites is frequency dependent. The real part of the complex permeability deteriorates in a high frequency range and the imaginary part has a peak after staring the deterioration. This paper tries to reveal that the frequency characteristics for some ferrites can be approximately derived from a first-order linear differential equation for the magnetic field intensity and magnetic flux density. The first-order differential equation is expressed by the reciprocal of the complex permeability and provides first-order magnetic and electric circuits for ferrite cores. In contrast with the commonly used series Rs-Ls circuit for the cores, obtained from B=(μ'-jμ")H, the derived first-order electric circuit is composed of the inductance (L) and resistance connected in parallel. In this paper, it is demonstrated that the inductance L remains constant, whereas Ls decreases with the increase in frequency. In other words, the real part of the reciprocal of the complex permeability remains constant for the frequency increase. In addition, it is found that the imaginary part of the reciprocal of the complex permeability is approximately proportional to frequency.

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Because the bulk-type YBCO superconductor prepared by the MPMG process has high critical current density J_c. It is expected to be applied to various fields such as magnetic bearing, magnetic levitation, magnetic shielding, and etc. In such applications it is important to develop measurement methods of magnetic property to high-T_c superconductor. It is necessary to value not only DC magnetic property but also AC magnetic property. So we measured magnetic pmperty of the high-T_c superconductor under the AC magnetic field (5-500Hz).
From the experimental results we can understand that there are two different kinds of elements in AC magnetic property: the one is the first order lag element by the flux flow, and the other is the applied magnetic flux that go around the ring specimen into that inside. The magnetic property in low frequency is ruled by the flux flow.

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This research is carried out to analyze the treeing phenomena with an artificial needle shape void by the discharge magnitude distribution and the luminosity distribution at each phase angle area at the same time. The discharge magnitude and luminosity are measured by the special measurement system to analyze the discharge pulses and discharge location of luminosity distribution according to several phase angle areas of applied voltage. Each phase angle area was named Ø₁-Ø₂₀ in order from the negative peak point of applied voltage. In this study, we focused on the discharge magnitude distribution and discharge location at each phase angle area. The luminous quantity at the tree area and luminous quantity in the void area was calculated by the luminosity distribution. The results show that the luminous quantity at the tree area is the maximum at Ø₇ and Ø₁₇. The discharge magnitude and luminous quantity at Ø₇ are larger than those at Ø₁₇. Therefore, the discharge at the phase angle area of Ø₇ is considered to be more useful information for analyzing treeing Propagation process.

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In electrical equipment used at very high temperatures, conductors must sometimes be insulated by the creeping distance of ceramic from the ground. The authors have conducted experiments on the surface flashover characteristics of ceramic insulation in air and nitrogen gas in the range of 40°C-700°C. Surface flashover voltage (FOV) was found to be generally higher in air than in nitrogen at lower temperatures. However, the difference between FOV in air and in nitrogen decreased with increase in temperature and they became almost the same above 400°C. In air, the temperature dependence of FOV was in accordance with the gas density, irrespective of whether or not there was a back electrode. However, in nitrogen, the temperature dependence of FOV had no correlation with. gas density either with or without a back electrode. It is considered that these differences in surface flashover characteristics are due to differences in discharge stability of both gases.

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Experiments and investigations were carried out on voltage life of a bar coil model with a nickel plated copper conductor covered with mica-alumina combined insulation at a temperature range of 550-850°C.
Diffusion of copper into the insulation layer was observed on the specimens aged for a long period. The insulation with mica paper was faster in the diffusion speed and shorter in the voltage life than the insulation with mica splitting. The diffusion speed became higher with the increase of temperature. Ac current gradually increased with the aging time, and increased rapidly just before the breakdown time. Betxeen ac current I and applied stress E, there was the relationship of I=aE ⁿ (a, n: constants). and n was approximately equal to one in the region where the thermal unballance did not occur. The Arrhenius s law held good in the relation between ac current and aging time. Therefore, breakdown mechanism might be that the effective insulation thickness decreased due to the copper diffusion into the insulation layer and the ac current increased gradually until the thermal breakdown at the last stage. If the diffusion of copper into the insulation layer occurs, even in the case with no voltage application, the aging time required to decrease the breakdown voltage to a certain level (the time is called as life here), obeys the Arrhenius s law. If the life is dominated by the diffusion into the insulation layer, the activation energy for the life in the aging test becomes twice that for the diffusion, irrespective of with or without voltage application.

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Non-destructive diagnosis using an optical fiber sensor was developed to evaluate the aging degree of thermally deteriorated insulating resins. The key point of this technique is measuring the change of optical losses in an insulating resin at the two different near-infrared wavelengths. The sensor consists of a plastic optical fiber, a plastic optical coupler, two kinds of LED light sources, and an optical power meter, so it is very compact and light (less than 2kg). The aging degree of a material could be estimated using a diagnostic master curve, which is obtained by a accelerated heating test. First, this diagnosis is applied to the prediction of the residual life of elevator motors.

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Dissociation in plasma enhanced chemical vapor deposition for SiO₂ deposition using Tetraethoxysilane (TEOS) was investigated by means of mass spectrometry. First we showed basic dissociation patterns of TEOS by electron impact. It was shown that the TEOS was dissociated by electron impact at low electron energy below 7eV removing the ethyl group (C₂H₅). Next we presented dissociation patterns in TEOS/He plasma in order to eliminate the effect of oxidation. Finally dissociation in TEOS/O₂ plasma was clarified. As the results, it was found that the oxidation plays a indispensable role for deposition of high quality SiO₂ films due to the decrease in high molecular compounds with carbon (C) and hydrogen (H) although the TEOS is highly dissociated by electron impact.

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The authors prepared organic light-emitting-diodes (organic LEDs) alternately deposited with diamine derivative (TPD) and aluminum quinoline (Alq3) and studied electroluminescence (EL) and photoluminescence (PL) properties using the dye-doping method. The actual emitting region of the specimen was found to be in some, not all, of the emission layers near the cathode. It shifted from the emission layer beside the cathode to one beside the anode depending on applied current, and it extended over several emission layers with the increase of current. EL spectra of the specimens with dyedoped emission layers did not have the effect of alternate deposition: the narrower FWHM of EL spectrum and the shorter emission peak than conventional organic LED with double layer. Considering the electron injection dependence of the emitting region and the contribution of the region beside the anode of narrower emission layer, the carrier recombination in TPD layer was concluded to play an important role of EL mechanism. The measurement of fluorescence lifetime directly proved the energy transfer from TPD to Alq3. The authors proposed the new model of EL mechanism incorporated the idea above.

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TiO₂ in anatase crystalline structure has strong photo-catalysis. In this paper, TiO₂ films are deposited on soda-glass substrate using a Ti cathode vacuum arc with O₂ flow. Experimental conditions are as follows: arc current, 50A; pressure, 0.3 and 1.0Pa; O₂ flow rate, 20ml/min; cathode-substrate distance, 250mm; bias DC voltage to the substrate, none and-300V. As-deposited films are annealed for 60min under atmosphere and vacuum. The following results were obtained. (1) Deposition rate is 0.07μm/min. (2) As-deposited films are amorphous. (3) Films annealed at 250-500°C have an anatase crystalline structure. These results are independent of pressure, bias, and annealing environment.
In another prosess, the films are deposited for 30min when the substrate holding table is connected to the anode chamber. Experimental conditions are as follows: arc current, 50A; pressure, 1.0Pa; O₂ flow rate, 20ml/min; cathode-substrate distance, 250mm. Almost 30‰ of the arc current was observed to flow through the substrate table, and the surface temperature of the table increased up to 450°C. The reason for this is considered to be that Joule heating occurs when the current flows through the film deposited on the table. The film deposited in this prosess is dominantly anatase.
The above experiments show that anatase TiO₂ film can be deposited on soda-glass by the reactive vacuum arc method.

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Pb (Zr_1-x, Ti_x) O₃ (PZT) ferroelectric thin films were prepared using the excimer laser ablarion technique. Optical emission of the PZT plasma plume was studied to understand the quantitative relation between the PZT film quality and the ablation plume plasma state. We identified the spectral lines originated in Pb, Pb⁺, Zr, Zr⁺, Ti, Ti⁺, O, O⁺, PbO, ZrO and TiO. These spectral intensities and dynamics have remarkable dependence on ambient O₂ pressure. The X-ray diffraction patterns showed that the PZT films propared on MgO (100) substrate at 600°C and with a laser fluence of 2J/cm² have a perovskite-pyrochlore mixed structure. The condition of 13Pa oxygen pressure provided high quality perovskite films. The ferroelectric properties of the Au/PZT/Pt/MgO structure were studied. The PZT perovskite structure (00l) was obtained on Pt (200)/MgO (100) substrate at 650°C. Polarizationelectric field curve for a PZT films with 200nm thickness showed a remanent polarization of 20μC/cm² and a dielectric constant of 500.

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This paper theoretically deals with electrical breakdown phenomena under a simulated quenching condition of high T superconducting coils. Bubble motion in liquid nitrogen under different electric fields is calculated and breakdown mechanism on the basis of the estimated bubble behavior is discussed. The basic electrode system is a Cylinder (Ø 10mm)-to-plane and applied voltage is changed between the breakdown voltage of liquid nitrogen and the one of nitrogen gas at the normal boiling temperature. The gap length is in the range of 0.5-40mm considering the practical space between coil turns, coil layers and coil wire to vessel wall in superconducting coils. The calculation results of bubble motion suggest that bubble behavior is influenced markedly by the gap length and applied voltage. Then the effect of thermally induced bubble on the breakdown voltage is suggested to depend on the gap length. Moreover it is found that distorted bubbles around the shortest gap may cause the reduction of breakdown voltage.

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