Polypyrrole (PPy)-silica glass composite films were prepared by carrying out the electrochemical polymerization of PPy simultaneously with the synthesis of silica glass by using the sol-gel processing and its electrochemical doping properties have been investigated by cyclic voltammetry. These films could be electrochemically easily doped and the undoped and doped states were yellow and blue in color, respectively. The redox process of PPy-silica glass has been gradually activated by repeating the electrochemical dopingundoping cycles. It was found that dopant anions in the PPy-silica glass composite film could be exchanged relatively easily with electrolyte anions in acetonitrile solution by potential sweeping. However, dopant anions in the PPy film cound not be easily exchanged in acetonitrile solution. Finally, application of this new type of PPy-silica glass composite film to the ionic sensor which responds to specific ions has also been proposed.

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The rf and microwave discharges have been utilized widely in the field of plasma processing. However, the discharges have been produced by either rf or microwave power and there has been very few experimental study for the discharge produced by both rf and microwave power.
In this paper, when microwave power was injected into a magnetized non-stationary plasma, which was generated by an inductively coupled rf discharge, the effect of the microwave injection is investigated experimentally. From the experimental results, the effect appears as a microwave discharge when an electron cyclotron 2nd harmonic resonance layer exists in vacuum chamber. The discharge due to the 2nd harmonic resonance does not occur by the microwave field alone. But, if there exist the plasma generated by an rf discharge, the microwave discharge occurs by this resonance in the latter-half period of an rf discharge pulse.

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Characteristics of magnetically insulated diode (MID) in a multi-shot operation are evaluated experimentally. MID is operated at V_d_??_1.2MV. An ion current density (J_i) of 350A/cm² is observed at a first shot when diode gap is 5mm. J_i decreases with increasing the number of shot and at 7th shot J_i is decreased up to 150-350A/cm². After 7 shots, the surface of anode was observed and found that it is covered with sticked matter of metallic materials such as Zn, Al, Fe, Cu. By cleaning the surface of anode J_i was recovered to the initial value. From the fact, the decrease of J_i is due to that the anode is covered with the sticked matter, which prevents the growth of anode plasma.

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An arc free KrF excimer laser was developed. Firstly, the formation process of an arc discharge in the KrF excimer laser was studied. By observing the waveforms of the charging capacitor voltage, the arc was found to be generated by the residual charge after the laser oscillation. In order to reduce the residual charge of the charging capacitor, a diode was connected in parallel. As a result, arc discharges in the KrF excimer laser were eliminated. Secondly, lifetime tests of the KrF excimer laser with this diode circuit were carried out. The results showed good improvement, such as 1.5×10⁸ pulses for the gas life, 2×10⁹ pulses for the window life, and 5×10⁹ pulses for the electrode life.

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In this papar, we observed a local discharge propagation on an electrolytic solution surface, which simulates the surface of wet polluted insulators, under an impulse voltage. Resistivity of the electrolytic solution was changed in the range of 85Ω•cm-3kΩ•cm. To examine a local discharge propagation, we used a Schlieren technique. A ray of light from a spark light source was transmitted to a electrode system.
As a result, we found shock waves and density changes. Shock waves were generated from tip parts of a local discharge. Velocity of the shock wave generated from a discharge during the local discharge propagation was about Mach 1.1. From a measurment of Mach angle, a local discahrge propagation velocity was obtained. That velocity at starting point of the propagation was in the range of Mach 2.5-4.7 for 85Ω•cm of the resistivity of the electrolytic solution, Mach 3.5-5.4 for 600Ω•cm, Mach 4.3-5.7 for 3kΩ•cm respectively.

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Corona discharge affected by an electrified floating-metal in unipolar ion flow field is of interest in understanding the flashover phenomena of non-uniform field gap with a floating metal which appears often in dc electric power system. In the present work, flashover voltage characteristics and corona mode in a positive needle-to-plane gap of 30 to 180 mm with a floating metal are investigated experimentally. The metal is sphere in shape for the simplicity of analysis and its radius was changed from 2 to 15 mm to find the size effect.
The results show that the sequence of corona discharge mode with the applied voltage is unchanged from that in the absence of floating metal, but corona activity and onset voltage of each corona mode are influenced strongly by the existence of floating metal, especially the metal location. The flashover characteristics are discussed on the bases of measured characteristics of corona mode.

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In our previous paper, we reported the relationship between the electrical treeing and space charge formed in low density polyethlene (LDPE) films. In the present paper, we measured the frequency (10-120Hz) dependence of the inception voltage of treeing and the length of the path generated in LDPE. We then measured thermally stimulated current (TSC) in LDPE films. We estimated the length of the path, the depth of electron injection and relaxation of space charge formed in LDPE by using the experimenOtal results of TSC measurements. From these results, we concluded that the length of the path generated by the electrical treeing was approximately as same as the depth of electerons injected by the application of AC voltages.

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Space charge formation in cross-linked polyethylene (XLPE) under AC voltage application were observed using Pulsed electro-acoustic (PEA) method. To observe the change of the space charge distribution with the changing voltage of AC, a new automatic measurement system with PEA method has been developed. Using the new system, it makes possible to observe the space charge formation at any phase angle of applying AC voltage. In this report, the frequency dependence from about 0.0002 to 50Hz (period T=20ms-80min) on the space charge formation were investigated. Under AC voltage stress with long period (T=40 and 80min), the accumulation of hetero space charges was observed. However, almost no space charge was observed under AC voltage with the period of less than 1min. From above results, it was found that a few minutes were required to form the space charge, which origin was residual byproducts generated by the crosslinking reaction.

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To study high-field AC conduction mechanisms of nonpolar polymers, AC dissipation current waveforms are observed. The shapes of the AC dissipation current waveforms in high-field and high-temperature region become a triangle one in spite of sinusoidal voltage application, suggesting a nonlinear electric field dependence of instantaneous AC conductivity.
The fast rising AC ramp voltage application method is developed as a new technique to examine the dielectric properties in a very short time range. This method enables the measurement of the variations of the high-field dielectric properties and the dissipation current waveform immediately after the voltage application. The new measurements were carried out on electron beam (EB) irradiated crosslinked polyethylene (IR-XLPE) film. The dissipation current waveforms of IR-XLPE in high-temperature region show the peak in the former part of each half cycle of a full waveform and quick decrease in the latter half part.
In this study, in order to discuss the transient response of high-field AC dissipation current of IR-XLPE film, the dissipation current waveforms observations in very short time range were carried out under the two types of AC ramp voltage application, one electric field increasing rate is 16kVrms/mm•sec and another 80kVrms/mm•sec. The results show that the transient response of the variations of dissipation current I_XR with electric field are different between at the increasing and at the decreasing of the applied field, and in the case of increasing rate is larger, the difference between the "increasing" and the "decreasing" is emphasized. From these results, we consider that the injected homo space charge would become hetero space charge at next half cycle under AC electric field., and then the carrier injection and extraction near the electrode become a dominant conduction loss mechanism due to the formation of the hetero space charge around the electrode. Based on the above hypothesis, we tried to simulate the transient response of high-field AC dissipation current under the different electric field increasing rage. The calculated results agreed with the experimental results.

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A composite insulation system of laminated tape and high vacuum is newly proposed for a superconducting bus-line cable operated at relatively low voltage. Its breakdown characteristics were investigated using the model cable specimens having different kinds of laminated tapes such as semi-synthetic paper, polypropylene film and kraft paper of the insulation thickness of less than 1mm. First, ±DC, AC and -Imp breakdown stresses of the semi-synthetic papers were investigated. +DC breakdown stress was 21.7kV/mm for specimen of insulation thickness of 1mm and -DC breakdown stress was 41.5kV/mm, so that the remarkable polar effect was observed. AC breakdown stress was 18kV/mm. Also, the ratio of-Imp breakdown stress was about 3. Furthermore, AC breakdown stresses of other tapes were investigated, however the remarkable differences among their stresses were not observed. The most of specimens were broken from "butt gap" between tapes. To make this cause clear, the measurements of the partial discharge were carried out. As a result, the inception stress of partial discharge of butt gap located just on the conductor was about 20kV/mm not depending on the kind of tapes. This value is much lower than the breakdown stress of the same length of vacuum gap. Therefore it is considered that the trigger of the breakdown of this insulation system is the surface discharge along the edge of butt gap.

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Electrical conduction and space charge distribution in oxidized low-density polyethylene (samples A1-A6) and copolymers of ethylene and carbon-monoxide (samples B1-B3) with different carbonyl contents have been studied. A V-shaped dependence of conduction current on carbonyl content was observed for samples A1-A6, while the current decreases monotonically with an increase in carbonyl content for samples B1-B3. The effect of polar groups on electrical conduction is discussed, focusing on their bonding forms in polymer molecules.

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The outdoor polymer insulating materials are exposed to acid rain containing strong acids, so that the surfaces of materials would be affected and their work performances such as the resistance to tracking, flashover and others would be decreased. In this paper, artificial acid rain which agrees with the actual ingredient and composition of the precipitation is used in the laboratory. After various samples are soaked in artificial acid rain statically, the surface hydrophobicity, tracking resistance, surface chemical bond of base polymer, surface crystallinity of inorganic filler and microscopic surface appearance for the soaked are compared with those for the original ones in order to observe the surface degradation process. EVA, Silicone rubber, Modified silicone rubber, Epoxy and Silicone resin coating are investigated. From the experimental results, it is found that some kinds of the inorganic filler are ionized and dissolved into artificial acid rain, and that this degradation phenomenon cuts down the tracking resistance. Moreover, the surface hydrophobicity decreases due to the exposure of the undissolved inorganic filler. Based on this investigation, the degradation mechanism of the hydrophobicity and tracking resistance of the outdoor polymer insulating materials due to acid rain is discussed.

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The formation mechanisms of paramagnetic defect centers in amorphous SiO₂ induced by excimer lasers, 60Co γ rays, and mechanical fracturing were investigated. Correlation between the paramagnetic defect centers and their precursors introduced during manufacture is discussed for the cases of excimer lasers and γ rays. For the case of mechanical fracturing, formation of strained Si-O-Si bonds as well as paramagnetic defects, is examined. Mechanism of laser or γ ray induced paramagnetic defect centers is compared with that of fracture induced ones.

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Electrooptic effects using a light scattering have been studied in a ferroelectric liquid crystalline polymer (FLCP) and a bistable switching has been demonstrated. The electrooptic effects including a deformation of helicoidal structure (DHS) upon applying voltage and a transient scattering mode (TSM) at the instant of polarity reversal of applied voltage have been observed in FLCP. FLCP transiently constructs the helical structure at the polarity reversal, and this helical structure maintains even after the removal of voltage. Using this principle, a new type of bistable switching between transparent and opaque states has been realized by means of the pulse voltage application.

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