Zinc oxide (ZnO) particles are well known for their non-linear properties. Recently, they are being used in epoxy resin of Air bushings to control the surface potential distribution. In this research work, we used 4 different types of ZnO particles (A, B, C and D) and measured their electrical characteristics. Among them, A and B were injected to epoxy resin. And the sample A was applied with high voltage (HV) application. Samples A, B and C were treated with heat for couple of hours before measurements. We have developed a measuring system by using a micromanipulator to measure the electrical properties of micro particles. The I-V and C-V characteristics of the samples were measured. We found non-linear properties in each particle while measuring I-V characteristics. Non-linearity appears for the DSB (Double Schottky Barrier) formed in grain boundaries. Microstructures of the samples were observed by a SEM. From their microstructures, it was confirmed that the I-V characteristics of ZnO particles depended only on the grain boundaries. We also calculated the donor concentration of ZnO and barrier height of DSB model from the C-V measurements. We found that the samples were not deteriorated either by HV application or the injection of them to epoxy resin.

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Polymer insulator has some excellent properties such as being lightweight, hydrophobicity, and antiweatherability. However, the polymer material is made from organic matters whereby the aged deterioration due to electric discharges, polluted deposited, and microbes is worrying.
In this study, we first investigated existence and kind of microbes on the surface of silicone rubber (SiR) insulators arranged outdoor for 11 years. Next, to investigate how the microbes influence insulation performance of polymeric materials, the salt fog tests were performed on SiR samples with the artificial cultured microbes. The microbes temporally increased the leakage current due to discharges; however, the degradation didn't continue because the discharges rejected the microbes.

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Desorbed gases from anode stimulated by electron irradiation are regarded as one of causes leading to vacuum breakdown. To understand the vacuum breakdown phenomena, it is important to analyze composition and quantity of electron stimulated desorption gases. Single pulsed electron beam irradiation method was developed for the detailed analysis of the desorbed gas characteristics. It is possible for this method to reduce the modification of surface condition due to electron beam irradiation and enables to measure the transition of gas desorption rate from the virgin surface state to a certain period. Using this method, we investigated the desorbed gases from oxygen-free copper electrode. It was found that electron irradiation caused H₂ gas desorption from copper electrode and the conditioning of the gas desorption. Moreover, a large amount of H₂ gas was desorbed when the first electron beam was irradiated. By using desorbed gases analysis method stimulated by irradiation with single pulsed electron beam, it is possible to observe change of gas desorption rate from virgin surface to a certain number of electron irradiated surface state. Analyzing desorbed gas from the sample in detail can evaluate the electrode material in vacuum.

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Electron emission is one of causes leading to electrical breakdown in vacuum. Distributions of field emission sites on a plane electrode before and after current conditioning procedure were investigated by using an Electron Emission Microscope. After the investigation of emission sites distribution, microscopic observation on some of the emission sites were carried out by using an Electron Emission Microscope. The observation revealed that field emission occurs at the foreign particles embedded on the electrode surface. To characterize the emission sites, we observed the absorption current image and analyzed the chemical composition of the emission sites by using an auger electron spectrometer. Observation and analysis suggest that the foreign particle was a semiconducting or insulating material composed of carbon.

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A design methodology for impulse generator for partial discharge test is developed. The fabrication of a generator is also described using a high-power semiconductor module. And the results of testing the generator on a variable amplitude DC power source, in arrow pair coils and form wound coil, are presented. The experimental results confirm the design and indicate how the required impedance of the generator for detecting partial discharge can be achieved.

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The mold transformers which use epoxy resins for coil insulation have superior characteristics in fire retardancy and environment resistance. Because of their high reliability, they have been excluded from electric equipment diagnosis in most cases. However, the mold transformers need to diagnose aged deterioration of their resin material because they have been used for more than 40 years. Therefore, we developed the simple and on-site degradation diagnostic device for the epoxy resin.

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The authors have proposed a detection method of the decomposed gas of SF₆ in gas insulated switchgear (GIS) using carbon nanotube (CNT) gas sensor. The previous studies focused on the decomposed gas generated by the partial discharge (PD) under AC or DC high voltages. In this paper, we demonstrated an application of CNT gas sensor for a fault localization method in case a grounding fault was occurred in GIS. The CNT gas sensor responses to SF₆ decomposition gases generated by an impulse arc discharge were measured for both impulse voltage polarities. Chemical gas analysis was also conducted to identify decomposition products, which were responsible for the CNT sensor response.

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We have proposed a new method using parallel array electrode system to prepare large-scale conductive composite film containing aligned multi-walled carbon nanotubes (MWCNTs). In the electrode system, the electric field generated by an array of interdigitated parallel wire electrodes was applied to the MWCNTs by using an electric field averaging scheme. The array electrode system made a large-scale composite film containing uniformly aligned MWCNTs. In this study, we investigated the relationship between weight fraction of the MWCNTs and electrical conductivity of the large-scale composite film. Measurement of the surface electric potential of the composite film after corona discharge exposure revealed that the film with an enhanced electrical conductivity obtained by electric field-induced MWCNTs alignment could serve as an antistatic film.

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The plasma jets produced by a dielectric barrier discharge have been studied using an optical detection system consisting of quartz fibers and avalanche photodiodes. The plasma jets are plasma bullets traveling at a speed of 27.6km/s. The emission intensities of plasma bullet increase with plasma bullet traveling and then decrease. It is found that plasma bullets are caused by electron avalanches due to positive space charges near the tip of glass capillary tube.

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In the Mt. Fuji weather station, lightning strikes frequently, so it is difficult to place the solar panels safely for long term. Also for the stable observation and research, the protection of lightning strikes for the outside experimental instruments is necessary. This research focuses on the clarification of the characteristics of lightning strikes at the Mt. Fuji weather station and suggests the countermeasures. The main countermeasures are two things; how to suppress invasion of lightning surge into the building using the return electromagnetic shielding at the Faraday cage damages, and how to suppress the lightning surge using the lightning protection cable which connect the outside observation equipments and the Faraday cage.

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We report the time course of nonlinear dielectric responses in living and dead cells of the budding yeast Saccharomyces cerevisiae with changes in their concentrations in suspension. To measure nonlinear dielectric responses, a sinusoidal electric field (1.2V/cm, 14Hz) was applied to the outer electrodes of a 4-terminal system and the response waveform was captured across the inner electrodes. Fourier transform permits determination of the harmonics or other frequencies not present in the exciting waveform. We measured the response waveform for 3 min and showed a relationship between the time course and relative harmonic contents. The results indicated that in living cells, the third harmonic content increased and the fifth harmonic content decreased with increasing concentration. The relative harmonic content of dead cells, however, remained similar regardless of the yeast cell concentration. The differences between living and dead cells became more conspicuous as the concentration increased. Observation of the responses permitted us to distinguish between living and dead cells.

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The principles and theoretical foundation of a method for realizing high-power generation are introduced. The external energy source for generating power is the total gravitational field energy. Sawtooth-pulse quasi-DC electricity is generated by an electric double-layer capacitor (EDLC) in an electrostatic field electromechanical system. Useful electricity can be generated by harvesting static charges that accumulate on the EDLC electrodes, which have high intrinsic surface capacitances. The system undergoes an electric cycle consisting of three steps: energy storage by electrostatic induction, power generation, and initialization by electromechanical coupling. A net output power can be generated by repetition of cycles with periods of the order of seconds. The electromechanical coupling was simulated by utilizing the gravitational field energy, which is available in the surroundings. This energy cycle obeys the law of conservation of energy.

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There is a movement of the shooting form to have a big influence on a score for archery. It is sport required to continue reproducing the same shooting form for giving high scores. Stabilization of the shooting form is usually accomplished by repeated practices of the instruction of the coach. However, it is unusual to see a special coach in high school extracurricular activities. Therefore we suggested the use of engineering technique to improve archery competence. We devised an electronic sight device which assisted the form construction and confirmed the effectiveness. From this result, we recognized the importance of keeping a fixed angle of the bow arm. In this study, we developed the device which visualized the trace of the bow arm by using the physical computing. By this device, an archer can recognize the habit of his form visually. With the devices which we developed, we suggest three phases of exercise methods.

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We have developed a high-performance thin-film multijunction thermal converter (TMJTC) with improved stability, and evaluated its frequency property, long-term stability, and environmental property using high-precision AC-DC transfer difference comparator system. We have fabricated a TMJTC with improved deposit pattern of a Bi-Sb-Cu based thin-film thermopile to avoid interface delamination between Bi and Cu layers. Our TMJTC shows good frequency property, which is less than 5μV/V in the range from 10Hz to 100kHz at the root mean squared (rms) voltage of 10V. The long-term stability has been significantly increased due to our thin-film thermopile compared with that of previously fabricated TMJTC, which is less than 2μV/V for 18 months at room temperature. We have also evaluated the temperature, relative humidity, and pressure property based on the International Electrotechnical Commission (IEC) standards for electronic devices. The measurement results have shown that the dependence of the AC-DC transfer difference on the temperature, humidity, and the pressure is less than 1μV/V, which can be comparable to those of thermal converters as the primary standard.

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We propose a new idea that the energy distribution of electrons flying in gas under an electric field is observed steady only when the flow rate distribution of electrons circulating the loop through a flight and a collision has converged at a steady form. Procedures adopted in the FTI method, determining the steady flow rate distribution Ψ_sn(ε₀) at first by iteratively operating the loop energy dispersion functions and calculating the steady energy distributions F_f(ε) and F_n(ε) from ψ_sn(ε₀) are just the same as the process that proceeds in nature. In this paper, the new idea and the essence of FTI procedures are described first, and the convergence behavior of ψ_sn(ε₀) in the case elastic and excitation collisions occur dependent on the collision frequencies proportional to the three powers of electron energy are investigated referring the newly defined convergence energy. Obtained transport quantities are discussed from the fundamental view point. The erratum reported in a previous paper is acknowledged with apology.

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Perfluorooctanoic acid (PFOA: C₇F₁₅COOH) in water has been decomposed effectively by plasmas generated at a gas-liquid interface. During the decomposition of PFOA, perfluorocarboxylic acids (PFCAs: C_nF_2n+1COOH) with shorter carbon chains (n = 1-6) are generated as by-products. Since these PFCAs are surfactant, they adsorb to the gas-liquid interface and show high surface concentration. This study investigated the relationship between the adsorbed amount of the PFCAs and the rate of decomposition by a dc plasma. The adsorbed amount of the PFCAs at the gas-liquid interface increased as the length of the carbon chains increased, resulting in a higher rate of decomposition. However, the reaction rate reached saturation with a certain adsorption amount depending on the discharge current.

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It is important to measure magnetostriction under mechanical stress in order to clarify the relationships between magnetic property and stress. However, it is difficult to measure the magnetostriction of the electrical steel sheet because the quantity of the magnetostriction is very small. In this paper, we examine measurement method with a lock-in amplifier to improve the measurement accuracy of magnetostriction. From the result, the lock-in amplifier is very useful to measure the magnetostriction of the electrical steel sheet in comparison with a commercial strain amplifier.

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Breakdown characteristics of air-polymer composite insulation under repetition of partial discharge have been studied using needle-plane electrode system. The purpose of this study is to clarify the effect of repetitive partial discharges and thermal properties of polymer on breakdown mechanism of air-polymer composite insulation under the application of pulse voltage. The experiments were also performed by inserting a thermal insulation film (TI) between an electrical insulating film for breakdown and the plane electrode. The number of pulse voltage up to breakdown (N_BD) was measured with variation of pulse frequency. With increasing the pulse frequency, the sudden drop of the N_BD appeared over a threshold of pulse frequency. The threshold frequency became lower by inserting TI. The results observed with thermograph show that surface temperature was increased with increasing pulse frequency and increased more remarkably around the threshold frequency. With insertion of the TI, the surface temperature rise appeared at lower frequency. These results on the breakdown characteristic and the thermal characteristic were successfully explained based on the numerical analysis of the thermal circuit.

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We have observed and reported that weak γ-ray was radiated from water treed samples. In order to study the influence of inorganic impurities such as metal ions in XLPE on the radioactivity, we measured X/γ-ray and neutron carefully from XLPE samples immersed in NaCl and/or Pb(CH₃COO)₂ solution using BF₃, CdTe and NaI detector in the condition of low background radiation. The counting rate of CdTe detector increased linearly with that of NaI detector, but each counting rate was not proportional to the growth of water trees. Furthermore, definitive residual radiation in the water treed samples, which attenuated rapidly to background level within a few hours after beginning of measurement, was observed by a Ge detector. We consider that the γ-ray observed during and after HV applying was emitted from ²¹⁴Pb and ²¹⁴Bi, as a result of analysis of the energy spectra. It is, however, difficult to explain that atmospheric radon gas (²²²Rn) which decays to above isotopes accumulated abundantly in water treed samples, because HV was applied in an air-tight flask filled with the solution. On the whole, these phenomena on the radiation of X/γ-ray do not seem to be directly associated with the growth of water trees.

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This paper presents a 2.5×2.5mm sized two-dimensional vector magnetic sensor (V-H sensor). The V-H sensor consists of B-needle probes for measurements of localized magnetic flux density vector B and a double H-coil for measurements of magnetic field strength vector H. The H-coil is made in very small size and the outside dimension is 2mm×2mm and the distance between B-needles is 2.5mm. In this paper, accuracy of the B-needle probe and frequency characteristic of the H-coil are evaluated and detailed two-dimensional vector magnetic properties in a magnetic circuit model made of a grain-oriented electric steel sheet are measured with the developed V-H sensor and results are compared with the crystal grain structure.

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We have investigated the shallow surface states relevant to electrification between polymer film and metal ring using photoelectron spectroscopy in air (PESA). As a result, it was shown that the charge transferred from metal ring to PET film depended on the work function of metal ring and the distribution of density of states (DOS) in PET film. Furthermore, it was found that the electrification between polymer and aluminium-ring was related to the chemical structure, i. e., pendand-group in polymer.

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The Polyvinyl chloride (PVC) is widely used as an insulating material in various electric products. It is reported that the exothermic reaction exceeding 150°C is caused due to the over-load current and/or inferior electrical wire connection before the ignition of electric products. The exothermic phenomenon may cause deterioration of insulating properties in PVC due to the chemical decomposition. It is necessary to clarify the degradation of insulating properties in PVC under thermal stress exceeding 150°C for the safe use of electric products. In this paper, the space charge distribution and conduction current have been measured in the range from room temperature to 200°C under DC electric field in the heat treated PVC sheet by using the high temperature PEA system. Positive charge injection and increasing conduction current are observed before breakdown over 100°C in the 100°C-300h heat treated samples and non heat treated samples. The obtained results indicate the thermal breakdown process from the analysis of conduction current and electric field. In more high temperature exposed (150°C-100h) sample, the breakdown strength strongly deteriorates in the range from room temperature to 90°C. And the increase of conduction current is observed in the all temperature range before breakdown in the 150°C-100h heat treated PVC. It shows that the heat treatment over 150°C deteriorates the breakdown properties in the range from room temperature to 90°C due to thermal decomposition on dehydrochlorination in PVC. The electric field is emphasized near the cathode due to the positive charge accumulation, and the breakdown strength begins deterioration only above 90°C. It shows that the thermal stress exceeding 150°C causes deterioration of insulating properties and breakdown process is affected by space charge formation in PVC.

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We examined the possibility of the emotion evaluation that used the near-infrared spectroscopy. As a result, the possibility of the objective evaluation by NIRS was shown.

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