An efficient self-consistent Particle-in-Cell/Monte Carlo (PIC/MC) simulator for rf plasma using higher order sampling technique called Legendre Polynomial Weighted Sampling (LPWS) has been developed in this work. The spatial distributions of charged particles in a discharge space obtained by LPWS show good statistics, as compared with the conventional PIC/MC performed with the same number of super particles. Also, the spatial distribution of electric field in the discharge space calculated from those of the charged particles by solving Poisson’s equation show good statistics, so that instability of simulation caused by the fluctuation of the electric field which readily occurs in a particle model simulation of high density plasma can be inhibited by the developed simulator. Calculation time of the PIC/MC simulator coupled with LPWS is almost the same as that of the conventional PIC/MC simulator. It is found that the results obtained by the developed PIC/MC simulation have a tendency to reach the steady state condition earlier than those by the conventional PIC/MC simulator.

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This paper describes results of time-frequency analysis of pressure wave caused by impulse tree extension using wavelet transform. Pressure waves were measured by a piezo sensor which was located on the back of the plane electrode when high voltage nanosecond pulses were applied to a point electrode in a low-density polyethylene block. Frequency of the pressure wave from induced charges on the plane electrode was higher than that of the pressure wave from tree. In addition, frequency of the pressure wave from tree tended to decrease with increasing the gap length because of dispersion of the pressure wave during its propagation. When a large tree extension occurred between a 5mm gap, pressure waves of about 10MHz propagated from tree tip and a pressure wave of 1MHz propagated from tree stem.

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In the electrorheological (ER) fluids of the disperse system, the poor dispersion stability of particles often limits the development of practical application of the fluids. This key matter can be settled by the chemical gelation of ER fluids. In the present study, the dimethylsilicone oil-based gel containing the non-aqueous ER particles was newly created. The dynamic properties on viscoelasticity in the sample silicone gel were examined under the DC applied electric field up to 2.0kV/mm using the sinusoidal oscillating rheometer with the low frequencies of 1Hz or less. The particle behavior and the shearing deformation in the sample gel were also observed using a microscope, a CCD camera and a color video monitor. When an electric field was applied to the sample gel, the gap between the electrodes was bridged by the chains of particles arranged in the direction of the electric field. Consequently, it is shown that the electroviscoelastic effect of the gel can be controlled by the electric field.

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We have studied on the applicability of the thermoplastic resins for GIS insulators. GIS insulators have been made of the epoxy mold resin. However, in recent years we should be careful to select plastics which are easily disposed and recycled. On this viewpoint, we selected some candidates of the thermoplastic resins, i.e. Polyamide, Polyacetal, and Poly-Phenylene-Sulfide to replace the epoxy mold resin, and evaluated these thermoplastic resins by several electric resistance tests. To examine the internal partial discharge resistance, we applied the CIGRE Method II test in which we modified the electrode arrangements. Poly-Phenylene-Sulfide had the longest lifetime in the test of internal partial discharge resistance, and worst property in the test of arc and tracking resistance. On the other hand, Polyacetal had a reversal tendency compared to Poly-Phenylene-Sulfide. As a result, thermoplastic resins showed enough characteristics in opposition to the epoxy mold resin in these electric resistance tests. The thermoplastic resins have possibility on replacement of the epoxy mold resin.

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Space charge profiles were measured in XLPE specimens cross-linked at different temperature. Negative hetero-charges were detected n the vicinity of positive electrode in specimens cross-linked at temperature above 180°C. After the decomposition products of DCP were removed, the hetero-charge disappeared and was not detected even after the specimens were soaked in acetophenone. The space charge profiles were measured also in XLPE containing anti-static agent. The negative hetero-charge was detected more clearly in the specimen containing the antistatic agent than in non-added specimen. Though the hetero-charge disappeared after the decomposition products were removed, it was detected again after the specimen was soaked in acetophenone. The hetero-charge creation in non-added XLPE was supposed to be due to the combined effects of decomposition products of DCP and the small amount of moisture in XLPE.

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This paper describes triangular surface charge methods (SCM) using fast multipole method (FMM) or tree method (TM) coupled with pseudo-particle method for calculating three-dimensional electric fields. FMM and TM enable us to calculate an N×N matrix and vector product of interacting N bodies by O(N) or O(N log N) times of operations and the same order of memories based on divide-and-conquer algorithm. Application of these techniques to the SCM allows up to utilize a million of surface elements on an ordinary personal computer system with 1GB main-memory. The calculated results of a benchmark-test and two examples, that is, straight and spiral chains of dielectric spheres in a homogeneous field show the validity and usefulness of the developed SCMs.

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We have studied and developed a high efficiency and a high repetition rate transversely excited atmospheric pressure CO₂ laser by an all solid-state pulsed power generator. The pulsed power generator consists of a high speed turn-on static induction thyristor and a single-stage magnetic pulse compression circuit using a saturable transformer. The static induction thyristor was improved in the switching speed and a switching loss. The saturable transformer with a Fe-based nano-crystalline magnetic core has two functions of voltage gain and pulse compression. The maximum switching voltage was 4.1 kV. The output voltage was 34.5 kV. On the other hand, the laser head is consisted of uniform field main discharge electrodes and corona preionized electrodes. Maximum laser energy of 3.2 J was obtained. The energy transfer efficiency of the pulsed power generator was 93% and the laser efficiency of 13.8% was obtained. An overall laser efficiency of 12.9% was obtained. The high speed static induction thyristor and the simple magnetic pulse compression circuit realized the high energy transfer efficiency and the high laser efficiency.

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Recently, air pollution has become a serious problem; acid rain, photochemical smog and the ozone hall are typical phenomena. NO_x is one of the air pollution substances and toxic gases. Thus, a decrease in the amount of exhausted NO_x is desired, since the density of NO_x in the atmosphere is remaining at a stable level or even worse. We have been particularly interested in the removal of NO_x in exhaust gas from a vehicle diesel engine by a discharge plasma method in which we proposed superimposing discharge methods. In this study, we use trenched type discharge reactor for NO_x removal. This reactor has saw tooth-shaped electrode and plate electrode with dielectric barrier. We expect that surface and silent discharges are generated simultaneously in the same space of reactor. The results show the following: (1) NO_x removal rate for the saw tooth-shaped electrode is much higher compared with parallel plate electrode at the same residence time and same discharge power. (2) NO_x removal rate increases with decreasing gap length between the saw tooth-shaped electrode and the dielectric barrier, in case of non-gap, surface and silent discharges were observed simultaneously in the same space of reactor. (3) NO_x removal rate increases with decreasing depth of groove of the saw tooth-shaped electrode.

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Model trees have been analyzed with multifractal of general fractal and global spectrum trees in polymer. However these results do not have information of the place. It is difficult to consider the mechanism of the development of the tree. The new method of local fractal dimension map is proposed to analyze the electrical tree. At first model trees of both polarities have been analyzed with the conventional and the new method. Actual impulse trees for both polarities have been also analyzed. The branching in the progress can be estimated quantitatively.

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According to the recent roadmap of semiconductor fabrication, it is predicted that the semiconductor market will demand 70nm node devices from 2004 or 2005. ASET (Association of Super Advanced Electronics Technologies) started “The F₂ Laser Lithography Development Project” in March 2000, developing the ultra line-narrowed F₂ laser system for dioptric design exposure tools. The final target of this project is to achieve a F₂ laser spectral bandwidth of 0.2pm (FWHM) at a repetition rate of 5000Hz and an average power of 25W. In this work, we have developed an engineering laser system consisting of an oscillator laser and an amplifier. With this laser system, we have tested two arrangements: MOPA(Master Oscillator Power Amplifier) and Injection Locking. Locked time ranges for injection locking system and MOPA were 40ns and 10ns, respectively, with stable output energy. A spectral bandwidth of 0.2pm and an energy stability (3 σ) of less than 5% at a repetition rate of 1000Hz with an average power of 14W was achieved for injection locked operation.

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Recent years, some developed countries have been promoted telecare systems to monitor elderly people living alone, or patients in private sickrooms. Most existing telecare systems use a monitor camera, therefore, the privacy of the examine is not protected. We have developed a new telecare system without a camera to save the clients privacy. The PTS (Pattern displayed telecare system) utilizing an FIS (Ferri magnetic infrared sensor) can measure human action patterns without a monitor camera, so it has the merit of protecting the privacy of the person being monitored. The FIS is an infrared sensing system using the magnetic change of the ferri magnetic film with the marked temperature dependence in the room temperature range. When the FIS array fitted on the ceiling or the wall of a room received infrared rays from the human body, it absorbs infrared energy which causes magnetic change, then the action of the client is patterned by the PTS in real time. The observed action pattern data may be sent to the observer through a communication network such as the internet. The paper describes construction of the PTS and its response characteristics.

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Piezoelectric transformer (PT) is a high voltage generating device which is small-sized and high efficiency energy conversion. Because of these features, the PT is used as power supply of back-light for liquid crystal display (LCD) and has promoted to the recent development in information technology (IT). On the other hand, we discovered that the PT does not only act as a high voltage generating device but also a silent discharge exciter. This paper describes the experimental result of luminous phenomena of the silent discharge using the PT. Spatial and temporal variations of the luminous intensity were observed by CCD camera systems. Spatial and temporal variations of electric potential at the surface of the PT are also measured using a probe electrode. As results, it was obtained that the luminous intensity distribution appeared around the PT corresponds to the electric field intensity distribution occurred by the polarization charge induced on the surface of PT which vibrates elastically. Moreover, it is also found that the place of light emission over the PT surface was determined by the polarity of potential induced on the PT surface. These results mean that the light emission around the PT occurs by excitation and ionization collision between electrons and N₂ molecules.

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