The mechanical properties for tensile and bending deformations are explored for silica particle reinforced composite. The adhesive effects between epoxy resin and silica particles are expressed as square root of boiling time steeped in water. Mechanical properties are reduced by water boiling. Silane coupling agent contribute to adhesion between epoxy resin and silica particles in composite. The reinforcing effects of composite are analyzed by rubber-particle reinforcing model.

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Fulgurite is a kind of mineral produced along the passage of lightning current in the sand, rock, etc., and is characterized by some natural quartz glasses. The production mechanism of fulgurite has not yet been clarified because the lightning is an accidental phenomenon.
In the present study, the authors succeeded in the artificial production of the fulgurite from the prepared materials in a container, passing through it lightning currents triggered by rockets.
The authors performed the physical and chemical analysis of this fulgurite.
So, we will explain the facts that we have observed.
(1) We have found the production mechanism of fuigurite.
(2) The passage of lightning current is instantaneous (ms). The temperature of the rock rose higher than 1000°C, and was dissipated in the next moment. The cross section of fulgurite has been studied by SEM. It has been found that two kinds of patches, a patch of unaltered material and a patch of the material solidified after the melting, coexist in the small area of a few mm².
It is believed that this is the first success in the artificial production of fulgurite by utilizing rocket triggered lightning in the world.

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A new analytical model is proposed to evaluate the pulse compression ratio and the efficiency in the pulse compression circuit using magnetic switches (MS). In the model, pulse compression ratio is described as functions of magnetic swing(ΔB) and switching energy density (charging energy of the capacitor/volume of core). From the evaluation, the core volume are found to be proportional to ΔB^-2 for same switching condition and only the cores having larger values of ΔB is found to be useful for MS. The efficiency of pulse compression circuit using MS is evaluated to be much higher than those of the circuits using spark gap switches or SCR. The difference of the efficiency is shown to be almost same when using amorphous metallic cores of iron based and cobalt based material.

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Effect of a thin insulation film on breakdown phenomena in liquid nitrogen in the presence of thermally induced bubble is investigated with a cylinder-to-plane electrode. Bubbles were produced by a heater mounted in the cylinder which is partially covered with an insulation film. The results show that the effect of film on the breakdown voltage is little till a pore is formed on the film by a previous breakdown, but it becomes very severe after the pore formation. The reduction rate in breakdown voltage after the pore formation depends on the gap length and heater power. The minimum breakdown voltage reaches down to the gaseous one at normal boiling temperature. Breakdown mechanism is discussed on the basis of bubble observation and numerical calculation of suspended-bubble motion.

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Recently, a non-thermal plasma which is produced by a silent discharge, surface discharge and double discharge in which many initial electrons are produced by a pre-discharge have been used for the effective production of ozone, and the treatment of NO_x and VOC (Volatile Organic Compounds). In this paper, a DC positive streamer corona with a wire-to-plane electrode is used to reduce the NO_x (NO and NO₂) which is fed from the gas cylinder filled by NO/N₂ or NO/N₂/O₂ mixture gas. The effect of the parallel discharges generated by two or three pairs of electrodes on the reduction of NO is also measured.

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In this paper, an evaluation method of computational error for the electric field analysis by a surface charge method is proposed. In the method, an approximate equation of the smoothness of electric field distribution is used to evaluate the computational error. In two-dimensional and axisymmeric problems, the approximate equation of the smoothness is expressed by the second derivative form of the surface change density with respect to the distance along the surface. Furthermore, the smoothness is expanded to the three-dimensional problems and a general form of the formula for the smoothness is obtained. The applicability of the proposed method is verified by computation results of a two-sphere model and a hyperboloid model.

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When an excimer laser operates continuously for long time, gaseous impurities are produced by the excitation discharge. The gaseous impurities reduce a laser output power.
In this paper, we propose to apply the technique of removal of gaseous impurities using corona discharge for excimer laser gas. This technique utilizes electron attachment characteristic of gaseous impurities. The removal of gaseous impurities of chromium fluoride and carbon tetrafluoride (CF₄) Were investigated. In the experiment of chromium fluoride, a corona discharge tube and a discharge chamber for the measurement of the emission spectrum from a sample gas were set in a closed gas looP. On the observation of the emission spectrum, it was found that chromium was decreased by passing through the corona discharge tube. The fact shows that chromium fluoride is removed by corona discharge. In the experiment of CF₄, the concentration of CF₄ was measured by the method of the absorption spectrophotometry. It was found that CF₄ was decreased by passing through the corona discharge tube. As the corona discharge current increased and the gas flow rate decreased, the removal rate of CF₄ increased. Approximately 96% of CF₄ was removed in this experiment.

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Two kinds of thin polyimide films are prepared by vapor deposition polymerization. One is annealed in air, and the other is annealed in a vacuum during imidization procedure. In this paper, electrical conduction in the two kinds of samples have been investigated with low frequency voltage, and the difference between them have been discussed from the view point of ionic conduction. The samples annealed in air shows lead of current phase that due to the accumulated ionic space charge in the vicinity of Al oxide layer at Al-polyimide boundary. The samples annealed in a vacuum shows lower conductivity and an anomalous current peak. The mechanism responsible for the peak has been discussed in terms of diffusion and drift of space charges accumulated near the electrode.

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Relationship between an external current J_ter(t), a conduction current J_c(x, t) and a displacement current ε∂E(x, t)/∂t of electron-beam irradiated PMMA is discussed using measurement results of a thermally stimulated current(TSC) and a thermally stimulated-space charge distribution (TS-SCD). The displacement current ε∂E(x, t)/∂t is calculated from the result of TS-SCD measurement which was obtained using an improved pulsed electro-acoustic (PEA) system. From the conservation of charge, the conduction current J_c(x, t) is easily calculated using the measured extemal current J_ter(t) and the calculated displacement current ε∂E(x, t)/∂t. In this report, an idea of the conduction current analysis using the theory of conservation of charge is described. Furthermore, an analysis of the conduction current in electron-beam irradiated PMMA is introduced as a typical example.

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