Theoretical analysis of XeCl excimer laser with the pre-pulse/PFN (pulse forming network) circuit is described, . In this analysis, we assume a zero-dimensional uniform discharge plasma, and a breakdown in the gap is produced only by self-avalanche electron multiplication process.
This circuit has different characteristics from the charge transfer circuit, that are a long laser pulse width of about 340ns, a complex evolution of the voltage between the electrode gap, and a relatively low partial component of Xe and HCl gas. However, the theoretical analysis for this circuit does not have been well studied.
The results of this analysis are as follows, (1) the role of the pre-pulse circuit is not only the initiation of the breakdown but also the raise of initial laser power, (2) the transferred energy from the PFN to the discharge is more than 80% of the charged energy on the PFN, (3) the temporal evolution of the electron multiplication during long pulse discharge period is explained, (4) the small signal gain and the absorption loss are estimated as about 3%/cm and 0.07%/cm, respectively.

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In order to make good use of solar energy, it is important to analyse the illuminance distribution due to skylight under various condition. In this paper, under two sky condition, CIE standard overcast sky and uniform sky, the illuminance distribution due to skylight incident from sky through perpendicular side face onto interior surfaces of a solid with a shape of rectangular parallelepiped is analysed. As a result, a series of equations for calculating direct illuminance at an arbitrary point on the interior surfaces and luminous flux incident directly on an arbitrary interior surface is proposed, and the total ratio of luminous flux distributed on interior surfaces (the base, side wall, front wall) to total luminous flux incident inside through perpendicular side face is graphed.

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The gases such as NO_x, SO_x and CO_x from a diesel engine, power plant, factory and so on contaminate the atomosphere. It is very important subject required to eliminate these pollutants from the point of view of suppressing the air pollution. The electro-chemical treatment such as a glow discharge has a great potential to decompose these pollutants. In consequence, we have investigated about the reduction of nitrogen dioxide (NO₂) component by using DC glow discharge.
The spatial and time variations of selected emission spectra such as N₂ and NO in NO₂ DC glow discharge have been obtained by using a computer-aided single photon counting system. Moreover, time variation of the total pressure in NO₂ glow discharge is also measured. In this article, some results of these measurements are applied to investigate the process of decomposing molecules of NO₂.

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We developed a deformable mirror whose surface profile is slightly deformed by nine actuators and varies the phase profile of a reflected laser beam. After Fresnel propagation, the complex amplitude of the reflected laser beam is transformed into another complex amplitude whose profile is different from that of the initial laser beam. Thus, the intensity profile of the reflected laser beam is transformed into another intensity profile with conservation of spatial coherency. We achieved reshaping of a circular-cross-section Gaussian laser (He-Ne:633nm) beam into a rectangular-cross-section beam using a deformable mirror for the first time. The wavefront of the transformed laser beam has a profile similar to that predicted by a beam propagation simulation.

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The electron swarm characteristics in gas mixtures containing CF₄ has been analysed over the E/N range 0.01-566Td by a multi-term Boltzmann equation method and by a Monte Carlo simulation. The differences between CF₄ and Ar, and CF₄ and N₂ mixtures, in electron transport coefficients have been explained by the calculated electron energy distributions and the respective sets of electron collision cross-sections. The synergistic behaviour and the dielectric characteristics in these gas mixtures have been also shown and discussed in detail.

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Tin Oxide thin films were deposited by DC magnetron sputtering. Remarkable peaks were observed in X-ray diffraction patterns for the SnO₂ films prepared at higher substrate temperature than 300°C. XPS measurement showed that as-deposited film was Sn-rich. Post-deposition annealling was effective to obtain stoichiometric SnO₂ films. The resistivity and carrier mobility of the films was 10^-3-10^-1Ω•cm and about 10cm²/V•s respectively. SnO₂ thin films showed n-type conduction. It was found that SnO₂ thin films had piezoresistive effect and gauge factor of the films was about 20.

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Measuring method of nonuniform electric field distribution in liquid dielectrics has been developed. The authors have published the reconstruction of field vector distribution in a space between two point-charge by computed tomography (CT) method. The errors in the reconstruction were rather large, more than 10% in field strength and up to 10 degrees in vector direction. The errors are decreased to 5% and 1 degrees by improved reconstruction program. Appling the method, field distribution in nitrobennzene and pure water is measured on planes which are parallel to the plane electrode in share to plane electrode.

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This paper deals with leader breakdown characteristics of SF₆ inhomogeneous gaps under positive lightning impulse voltages. The high voltage electrode is a thin aluminum sheet whose thickness is 100μm, the grounded electrode is a plane electrode, and gap length is 50mm. To control the electric field at edges of the sheet electrode, we used the electric shields that are four types.
It is found out that breakdown voltages can be estimated by a supposition of space charge which acts like the electrodes around the edges of the sheet electrode. We named this space charge "Imaginary Electrode", When the electric field of Imaginary Electrode surface reaches the critical field, a leader breakdown occurs. With the present experimental electrodes, electric shields don't affect the radius of Imaginary Electrode, but gas pressure affects the radius of Imaginary Electrode, which is 0.25mm at 0.5MPa, 0.5mm at 0.3MPa, and 3.0mm at 0.1MPa. This gas pressure dependency of the radius of Imaginary Electrode is influenced by the structure of inhomogeneous electrodes.

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Crystalline polymers such as polyethylene and polypropylene have been widely used in power cable and power condenser because of their high electrical strength and low dielectric loss. The spherulites would be formed on the cooling manufacture process of these polymeric materials. It is known that electrical insulation performance of the polymeric material is influenced by spherulites. However, the influence of spherulites, spherulite distribution and annealing on tree initiation is not entirely distinct so far.
In this paper, isotactic polypropylene film is used. Three kinds of samples were made that spherulite distribution is different. And then tree initiation voltage was measured. Crystallinity and crystal structure are studied by Infrared Spectrophotometer and X-Ray Diffractometer, respectively. The Effects of space charge, internal strain and spherulite permittivity on the tree initiation are discussed. The influence of spherulite, spherulite distribution and annealing on tree initiation is made known.

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Polyethersulfone has two TSC (thermally stimulated current) peaks below the glass transition temperature of 225°C. The peak temperature of the lower-temperature TSC, β, increases with an increase in the pollng temperature. Through the measurements of space charge distribution by the pulsed electroacoustic method done in combination with the TSC measurements, β peak is considered to be due to ions. Furthermore, the dc conduction current obeys the ionic hopping conduction model, suggesting that the dominant carriers are ions.

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By using a needle-plane electrode system, electrical treeing discharges were measured with a computer-aided partial-discharge measurement system. It was found that time derivative of applied voltage (dv/dt) plays an important role in determining the occurrence of partial discharge (PD), while PD intensity is strongly determined by the applied voltage. Based on the measurement results, a model for electrical treeing discharges was proposed. The effects of applied voltage and frequency were also investigated by applying triangular voltage. The experimental results were compared with the proposed model. It was found that the model could explain the voltage and frequency dependence of electrical treeing discharges.

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It is already known that partial discharges in a void in insulating materials and between a polymer and a conductor, may lead to degradation of insulating materials, and finally to breakdown of the insulation system. The occurrence of the partial discharge depends on a shape of void and atmospheric condition. The object of this work is to investigate the degradation process of polymeric materials under various humidities in a void.
The characteristics of the gaseous discharge products were analyzed by Fourier Transform Infra-Red Absorption Spectroscopy during the discharge condition. At the same time, the discharge magnitude distribution was measured by a special internal discharge pulse measurement system which could analyze the discharge magnitude according to the phase angle area of the applied voltage. The effect of water on the degradation of insulating materials in void exposed to partial discharge has been investigated by the FT-IR analysis and the measurement of the discharge magnitude distribution in each phase area.
As a results, the time to breakdown for 50% humidity is shorter than at that low and high humidity conditions. The time dependency of carbon dioxide differs from the case of humidity. Carbonyl group increases, and end vinyl group decreases with the discharge deterioration time. Moreover, the discharge magnitude in all phases at 50% humidity is greater than at that low and high humidity condition.

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