A 150J carbon dioxide laser focused by a 5m focal length concave mirror is transmitted into a rod-to-plane gap which is dc electrically stressed. The breakdown voltage of the gap with a laser irradiation is decreased down to 40% of the normal breakdown voltage without the laser irradiation in the case of negative voltage applications to the high potential rod electrode. On the other hand, in the case of positive voltage applications the breakdown voltage with the laser irradiation becomes 60% of the normal breakdown voltage. The guide effect of laser-induced plasma to electrical discharge appears clearly when a bright plasma channels are produced between electrodes.

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An attempt to explain the phenomenon of the effect of electrode rotation on the ozone generationprocess will be presented. An ozonizer with an electrode rotating system may be one of the possible waysto increase ozone synthesis efficiency. The presented research shows that, with electrode rotation theozone generation efficiency increases about 15% compared to an ozonizer with a non-rotating electrode.Also during the research an attempt will be made to find the most suitable electrode rotational speed for the ozone generation process.

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Two materials, W and Cu, for HV electrode using wire-to-plane discharge system were investigated under conditions of DC positive corona discharge in order to compare their influence on deNOx. Removal rates of NO were measured as a function of time and discharge power. Two wire states were studied: 1. Nonroughened material, 2. Roughened material. The purpose of roughening was to vary the mechanical and chemical properties (surface damage and oxides presence) which would affect the discharge conditions and, thus the removal rate of NO.

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For nozzle-to-plate electrodes with a gap distance of 43mm, onset streamer occurs with a length of about 1.0-1.5cm when the applied voltage is increased to above the onset voltage Vc. Depending on gaseous compositions, onset streamer may become full streamer to cross the electrodes gap or transfer to the Hermstein glow with increasing the applied voltage. After streamer (peak current_??_60mA) bridging the gap, a long duration Townsend like glow discharge may be also formed, which may lead the spark breakdown. Bridging electrodes gap by streamer does not necessarily lead to spark breakdown. However, spark breakdown occurs only after streamer bridging the gap and a streamer channel, or Townsend like glow discharge, is formed between the nozzle and the plate. Moreover, spark breakdown occurs after a significant increase of the repetition rate of the self-sustained streamers. Depending on the average glow current, the time delay from streamer bridging the electrodes gap to spark breakdown ranges from 0.5 μs to 25 μs within test conditions. With regard to the attachment stability inside streamer channel, a simplified criterion for streamer-glow-spark transition is also discussed in this paper. Theoretical estimations of the time delay are in good agreement with the experiments.

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In power station or substation, central control panels are connected with other equipment for thousands of cables. Under the condition, cable locator that could locate many cables in thousands cables in a short time is desirable. Therefore, we developed pulse injection cable locator and confirmed its performance. The equipment has no need to operate cable far-end and because of little dependency of sensitivity from cable length, input level adjustment is very easy. By grouping cables, injection coded pulse in time division to many cables, and using personal computer to collect receive data, it is possible that cable locator locates many cables automatically in a short time.

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The method of Huang's expectation value extracts for a free particle the particulate from the wave function in quantum mechanics. His method is used to investigate the Zitterbewegung of Dirac electron, which disappears in a usual expectation value. Explicit form of the Zitterbewegung as a particle motion is obtained. The uncertainty at the velocity of Dirac electron are examined closely.

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In present paper, a wavelet based method is proposed for the numerical calculation of singular integrals in light of the orthogonal and compact support features of wavelet bases. The key point of this new approach is that the integral is proved possibly to be computed at a very low resolution level. A new decomposition procedure is also proposed based on the Mallat's multiresolution algorithm in order that the singular kernel of the integrand function can be decomposed from a high resolution level. The applications of this method to an one dimensional singular integral and to the surface integral term of an eddy current analysis formula (T method) show that the wavelet integration method can both give a high accuracy and reduce computer burden in practical calculations. Finally, a surface singular integral utilized in the three dimensional eddy current analysis is discussed by comparing analytical results with those evaluated by the present and conventional numerical approaches.

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A Monte Carlo technique is used to investigate the electron transport and to compile data on the transportparameters in SiH₄/Ar mixtures under a wide range of the electric field from E/p₀=20 to 1000 V/cmTorr andSiH₄ mixing ratios from 0 to 100%. The calculations show that the drift velocity v_d, the diffusion coefficientp₀D_L, and the electron mean energy εdecrease monotonously with increasing the silane content, except thecase in a low electric field. On the other hand, the ionization rate Ris, the attachment rate R_at, the vibrational excitation rate R_vb13 and R_vb24 and the dissosiation rates R_d2, and R_d3, of the silane molecule have a maximumvalue at a certain mixing ratio. The ionization rate R_ia and the excitation rate R_ext(1-6) of argon atom, however, decrease sharply with increasing the silane content. These results are discussed using the data on thevariations of the electron energy distribution due to the electric field strength and the mixing ratios.

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Constructual study of a pair of parallel plate has been carried out for generating an enhanced hollow cathode effect. Unique feature of the hollow cathode discharge is the result that a fraction of electrons released from the cavity surface can undergo a limited number of ionization, reverse direction and repeatedly across the glow region. This possibility of making multiple passage across the two dark spaces and a glow region depends on the relative size of the separation of the two-parallel plates to the sum of the thickness of the two cathode dark spaces. Consequently, this research is to determine experimentally the optimum separation for obtaining the enhanced hollow-cathode-effect and also to discuss effect of depth of the hollow space. Three gases (Ar, Ne, and N2 ) and three materials (Ni, C, and Al ) combinations which are commonly used for H.C.D. are examined. The optimal separations (p•dm) determined by this experiment range from 0.8 to 1.2[cm•Torr] depending on gas species and materials studied independent of the operating pressure. The minimum depth to obtain H.C.E. is also determined as about 2.5 times of the cathode separation irrespective of the gas and materials studied. Therefore, over depth deeper than 2.5 can sustain the enhanced H.C.E..

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Miscellaneous solid waste contains burnable and/or non-burnable materials besides metallic waste. When non-metallic waste is treated by transferred arc plasma, plasma stability may be decreased by the low electrical conductivity of the materials. This paper describes the result of an experiment in which rubber and wood chips as typical burnable wastes were fed into the crucible of an operating experimental plasma furnace. The average power of the plasma was 20 to 50kW, however it fluctuated at waste feeding. The base materials of the simulated waste were 10kg of steel and 3kg of fly-ash. Up to 8g of burnable waste was fed after the base materials had melted. The voltage of the arc plasma increased just after the feed, and the increase was almost proportional to the weight of the fed waste. The intrusion of thermally decomposed products of the waste into the plasma dominated the voltage increase. The voltage increase was investigated for several operating conditions of the furnace. The increase of air injection into the furnace and that of arc current controlled the voltage increase during feeding, but the increase of plasma working gas aggravated it.

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There are several important environmental problems in the world. One of them is the acid rain caused by combustionflue gases from thermal power plants, factories and automobiles. Different kinds of gas discharges, such as surface discharge, dc and ac corona discharge, silent discharge, and electron beam controlled discharge, have been studied for the removal NO_x and SO₂ from flue gases. The recent development of repetitive pulsed power generators gives the pulsed streamer coronadischarges a chance of success in the removal of NO_x and SO₂.
In this paper, the experimental results of NO_x and SO₂ removal by a repetitive pulsed power generator are described.The actual flue gas at a thermal power plant was used. It is shown that about 90% of the NO was removed at a flow rate of0.81/min and a repetition rate of 7pps.

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Study of laser triggered lightning has been conducted at field experiments. The experimental site was constructed at Mt. Dake close to the Japan sea shore in Fukui prefecture. An electron-beam sustained two-beam 1kJ CO₂ laser, 500 and 1000-mm diameter Cassegrain type focusing mirrors and a 50-m tall lightning tower were prepared. To produce a plasma channel for leader initiation, a plastic target was set at the top of the lightning tower and irradiated by the CO₂ laser. An aerosol plasma channel was also produced from the top of the plastic target. The laser plasma channel successfully triggered a lightning stroke. Rogowski coil current detectors monitored the current growing rapidly and UHF interferometer set on Goichi observation site was detected an UHF radiation from Mt. Dake as same timing as the laser irradiating. The UHF radiation was correlated to the leader initiation both in time and space. Hence, we confirmed the laser triggered lightning.

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With the developments of modern central processing unit (CPU), electromagnetic field coming from the printed circuit boards (PCB) is becoming a serious electromagnetic noise source. In order to reduce the noise coming from the PCB, it is essential to evaluate the current distribution on the PCB.
This paper proposes one of the promising methodologies evaluating for the current distributions from the measured magnetic fields. At first, the unknown current distributions are modeled by the loop currents. Second, we derive a system of equations by means of the elliptical functional approach, and solve the system equations which unknown parameters and equations are matched. Finally, we have succeeded in obtaining the current distributions on model PCB. And then, we applied same procedure to measured magnetic field distributions on the PCB of workstations in time region by loop probe. We demonstrate the usefulness of our methodology by applying to these magnetic field distributions.

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Linear silicone chains synthesized from dimethyldiethoxysilane are applied to a heat resistive coupling agent in polyamideimide(PAI) composite containing glass. The silicone chains have an effect on improving glass-PAI adhesion. It is also concluded from the results for aged samples that the degradation of silane coupling agent brings about the decrease in dielectric breakdown, and that silicone chains serve as a heat resistive coupling agent.

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We have measured dielectric properties of filled epoxy resins immersed in water at 50 °C. The loss tangent tanδ and dielectric constant ε_r' of the resin filled with square shape silica was intensely influenced by water absorption. But the resin filled with roundish shape silica was independent of water absorption. The filler particle size had the influence on the water absorption. But the dielectric properties are independent of the particle size. The change of dielectric properties in water absorption should be understood that the water immersed into the bulk along the interface between filler and epoxy resin. We can tentatively explain the influence of the particle shape by the spheroidal model having high conductivity and dielectric constant.

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Digital feedback technique has advantages of good reproducibility of waveform due to no human error and of no oscillation in control process compared with analog technique. However, it may require many iterations of feedback, especially at higher flux densities, because a considerably distorted voltage waveform should be generated to keep the flux waveform of specimen sinusoidal. In this paper, a robust method of waveform control for measuring magnetic properties by means of a single sheet tester is proposed. An initial voltage waveform generated by a D/A converter is estimated by using the equivalent circuit of measuring system, and an efficient technique for adjusting the maximum flux density is applied after the estimation of initial voltage waveform. The effects of air flux compensation and yoke construction on the measurement accuracy are also discussed. It is demonstrated that the waveform control can be converged within a few feedback iterations even at high flux density of nearly 2T.

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Bulk-type YBCO superconductors prepared by the MPMG process exhibit the high critical current density Jc, and are promising for many practical applications such as magnetic levitation. A magnetic levitation system is to use as a strong superconducting bulk magnet by magnetizing the high-Tc superconductor (HTSC). When superconducting bulk magnets are activated using the field cooling procedure under a DC magnetic field, a large electromagnet system or a superconducting coil is needed. In contrast, a pulsed magnetic field using a small coil is applied a strong magnetic field for magnetizing the HTSC. Therefore, it is important to evaluate the pulsed field magnetization properties of the HTSC. Since superconducting properties are not homogeneous in some specimens due to grain boundaries and cracks, spatial distribution of magnetization properties should be assessed. In the present research, the distribution of the pulsed field magnetization was measured with a magnetic field visualization system.
The magnetization with the pulsed magnetic field is done in the state of the zero field cooling. However, it is necessary for enough magnetization of the HTSC to consider the time constant on the magnetic flux invasion and the flux flow, when the applied magnetic field decreases. Therefore, we examined the optimum pulsed magnetization for the HTSC. The optimum value of the pulsed magnetization existed.

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Potential distributions on the surface along the corona shield layers of high voltage coils for rotating machines are measured by a new static potential meter. The corona shield materials have non linear electrical high resistance and linear electrical high resistance. So it is difficult to measure the potential distribution on the surface of these materials directly. However this measuring meter is possible to generate the same potential as that on the measured surface. This means the input impedance of this measuring meter is infinite. These measuring data are almost the same as the simulated data. This new method for measurement of potential distribution is useful for the surface potential distribution on high electrical resistance layers such as the coil end parts of rotating machines.

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With the recent increase in the attention of low frequency electromagnetic environment, we focus on the induced current density in the conductive object exposed to mutually parallel and orthogonal low frequency electric and magnetic fields. In this paper, effects of the electric and the magnetic field components on the total induced current density in a homogeneous spherical conductive model exposed to 60 Hz electric and magnetic fields is investigated through computer analysis. First, each of the distribution profiles of the induced current density in the model exposed to the electric and the magnetic fields is different. The magnitude of the induced current density of the electric field is maximum under the applied conditions. Second, the distribution profiles of the induced current density in the model exposed to low frequency electric and magnetic fields in parallel with each other are almost dominated by the electric field but the one exposed to mutually orthogonal low frequency electric and magnetic fields is different. Third, the total induced current density is affected by the relationship between the magnitude and the phase difference of the mutually orthogonal low frequency electric and magnetic fields. These results show that the relationship between mutually orthogonal low frequency electric and magnetic fields has strong effect on the total induced current density in the model exposed to the ordinary electric and magnetic environment.

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The ablation process of graphite target flashed by a pulsed KrF excimer laser is studied numerically. The thermal effects of target evaporated by nanosecond laser pulse are investigated. The dynamics of pulsed nanosecond laser ablation process is simulated by solution of the one-dimensional heat conduction equation. The finite element method (FEM) is applied to solve the equation including the temperature dependence of the thermal conductivity and heat capacity of graphite, the movement of a vapor-solid interface, the latent heat of vaporization, and the energy of laser-generated plume. The heat of vaporization and the energy loss due to the material removal are included in the simulation. The ablation threshold energy density for graphite flashed by a pulsed KrF excimer laser is 0.64J/cm². In addition, the thermal energy of the laser-generated plume begins to increase from the laser energy density of 2J/cm² and attains the value of 83.0kJ/g at the laser energy density of 5J/cm².

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In attempt to clarify the electrical treeing degradation, we investigated the characteristics of partial discharge (PD) by utilizing φ-q-n patterns and PD pulse sequences from an artificially-simulated tree channel within low-density polyethylene. At most one PD pulse occurred in half cycle in our experimental condition. PD's appeared in several consecutive cycles and then ceased for several cycles, forming PD pulse trains with discharge free intervals. There existed a strong correlation between positive and negative PD pulses occurring in two consecutive half cycles. These results are explained by trapped charges on channel wall due to the preceding PD. The PD pulse trains tended to end with a positive PD pulse. It is explained in terms of the suppression of a negative PD pulse due to the field reduction by the negative space charge near the needle tip. It is useful to investigate characteristics of PD's in an artificial channel in order to clarify PD characteristics in an actual tree channel.

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We have optically studied the dynamics of the plasma plume during preparation of diamondlike carbon (DLC) thin films andcarbon nitride (CNx) thin films by the pulsed laser deposition method. We report on spectroscopic properties of laser plasma plumeproduced during the DLC and CNx thin film deposition. It was found that carbon atoms and ions emitted from the target react withambient gases of hydrogen and nitrogen. CH and CN molecules are formed in the gas phase. The properties of DLC and CNx thinfilms are strongly affected by the laser plume dynamics. Some conversion mechanism of C₂ radical to CN radical probably exists.

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The authors have studied on the growing mechanism of diamond structure using negative ions by physical vapor deposition technique. It is considered that diamond structure will be changed to graphite structure by positive ions, because ionization energy causes thermal chemical reaction. On the contrary, negative ions restrain thermal chemical reactions, because of electron affinity. From the experimental results, it is shown that negative ions were more effective than positive one to grow of diamond structure.

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