XLPE power cables have been in use for long time now and some of them are approaching 30 years of their designed lifetime. However, under the present severe economic situation, it is necessary to use the existing apparatus as long as possible. So, degradation diagnostic methods with high reliability are needed earnestly. This paper explains the insulation degradation mechanism of XLPE power cables and the newest diagnostic methods on each voltage class. In 3.3-77kV classes, fairly high extents of the cable accidents depend on the water-tree degradation. For 3.3-6.6kV class cables, on-line diagnostic methods with high reliability to detect bridged water-trees have been developed and put in practical use. And, for 22-77kV classes, two promising off-line diagnostic methods to detect un-bridged water-trees have begun to carry out in on-site tests.

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One of the applications of the ESP is the cleaning of the air to increase the visibility index in highway tunnels. Most of particles in the highway tunnels are composed of carbon. Decrements of the collection efficiency due to particle agglomeration on the electrode and re-entrainment phenomena are important problems when ESP collects carbon particles that are low electric resistivity. In the previous experiments, the coarse particles on the collecting electrode accumulated on midpoint of the collecting electrode. Generally, almost collected particles start accumulating from the upstream area on the collecting electrode surface. In this work, the particle collection was observed in real time because of clearing for the behavior of collected particles. And then, particle collection and particle huge re-entrainment phenomena processes were observed. In the closed space to the collecting electrode surface, gas-flow velocity at the upstream area is faster than that at the downstream area. Hence, particle re-entrainment phenomena are convenient to occur in upstream area. As results, it has been shown that collected particle re-entrainment phenomena are pertinent to the gas-flow distribution.

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The high-current interruption ability of the vacuum interrupter depends on the state of the residual plasma remaining between electrodes after an current zero. In this study, the copper vapor density around the current zero with a half-period of 1 ms and a peak current of 3 kA arc was measured using the laser absorption method. The copper vapor density found to be 8×10¹⁷ m^-3 at current zero and was found to be independent of current zero gradients and arc current peak. After current zero, the copper vapor density decayed with a time constant of approximately 400 μs. The decay time observation by LIF signal agreed well with that of the absorption method. This decay time of the copper vapor density can be explained based on the calculation of the cooling characteristics of the cathode spot crater which supplies copper vapor.

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The nighttime visibility of LED type outdoor display gets deteriorated due to the glare in the case of high luminance, while in the case of low luminance the visibility is enhanced, but not very conspicuous. The glare is caused by the high contrast. Therefore we inferred that the visibility may be improved by lowering the excessively high contrast. We can control the contrast by feeble lighting of the LED’s of the background part which are usually unlighted. We conducted a series of experiments to investigate the effect of the background lighting on the visibility. We found that the visibility is improved for a certain range of contrast, 4:1 through 100:1. It is suggested that for the above range of contrast, the glare is suppressed and yet the displays conspicuous.

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A DC corona discharge induced electrohydrodynamic (EHD) flow phenomenon for a multi-phase fluid containing a vapor-phase dielectric liquid in the fresh air was investigated. The experimental electrode system was a simple arrangement of needle-plate electrodes for the corona discharges and high-resistivity silicon oil was used as the vapor-phase liquid enclosure. The qualitative observation of EHD flow patterns was conducted by an optical processing on computer tomography and the time-series of discharge current pulse generations at corona discharge electrode were measured simultaneously. These experimental results were analyzed in relationship between the EHD flow motions and the current pulse generations in synchronization. The current pulses and the EHD flow motions from the corona discharge electrode presented a continuous mode similar to the ionic wind in the fresh air and an intermittent mode. In the intermittent mode, the observed EHD flow motion was synchronized with the separated discharge pulse generations. From these experimental results, it was expected that the existence of silicon oil vapor trapped charges gave an occasion to the intermittent generations of the discharge pulses and the secondary EHD flow.

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It was found that carbon with an extremely steady characteristic can be obtained by baking the furan resin, one sort of thermoset high polymer in the condition of 3-4°C/h up to 200°C and 7-8°C/h above 200°C respectively in N₂ gas and He gas atmosphere. Relatively few researches have been done so far of the high molecule carbon as a bulk material such as the one we did. The application as an industrial material can be expected by further elucidation of physical properties.
In this report, we will report the study on the impact style type wheel for the high-speed printer. Impact style high-speed printing type with a lower weight and a smaller wearing loss as compared with the metal type could be produced from carbonized furan resin through a simpler production process. The printing wear loss of carbonized furan resin is nearly zero by 1,800,000 times printing.

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The history of development for the power transformer is equal to the history of development for the alternating current transmission systems. The rated voltage and capacity of power transformer were increased depend on the great demand of electrical power. On the early stage of development for the power transformer, the main technology had been imported, but Japan has leaded the reduction of the partial discharge and the wise solution for the problem of the oil flow electrification with the development of 500kV power transformer. In the future, it will be important to make a solution for development of UHV transformer and environmental problem.

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The eddy currents in heating irons induced from ferrite-core induction coils are calculated using a theoretical approach and the results are compared with experimental data. Optimizations of components and materials for constructing the induction head are investigated to develop new type induction heating irons. Formulations in our theory are based on the magneto-resistance calculations. The self- and mutual- inductances are estimated precisely using these magneto-resistances. Induction heating phenomena are analyzed theoretically using the eddy currents. Finally, the heated iron is shown in good agreement of parameters.

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This paper describes experimental results of NO removal using barrier discharges produced by a reciprocal pulse generator. When a coaxial cable is charged and then grounded at one end of the cable without any resistance, a reciprocal traveling voltage pulse is repeatedly applied to a barrier-type reactor at the opposite end with a change in its polarity. 50% streamer initiation voltage for the reciprocal pulse generator was much smaller than that with the self-matched pulse generator having a matching resistance. The reason for the low initiation voltage in the reciprocal pulse was that space charges which accumulated on the barrier surface during cable charging had an effect on field enhancement in the reactor after the first polarity reversal. High speed photographs of discharge light produced by the reciprocal pulse showed that the voltage oscillation caused by one switching induced alternate propagation of positive and negative streamers with a very high frequency. In measurements of NO concentration, the reciprocal pulse generator gave a better performance for NO removal ratio than the self-matched pulse generator even though the stored energy in the recipocal pulse generator was very low.

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A bypass circuit is set up in the secondary winding of ballast for the leakage transformer type operating circuit for a metal halide lamp.
It is shown from computer simulation and experiment that harmonic element containing rate of the power supply current wave form of the operating circuit can be controlled to be small by deciding optimal tap position of the bypass circuit and optimal values of circuit constants of the bypass circuit.
It is shown from experiment that the power factor of power supply current is about 100% by setting up a capacitor for the power factor improvement in the arrangement at the input terminal of the operating circuit.

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In this paper, experiments were conducted to study the electrical I-V characteristics of the polymer Positive Temperature Coefficient (PTC)resistor as a function of joule heating due to I²R. More than 80short-circuit tests were carried out on four samples (rated 60V/40A), and the results show that all PTC samples tripped when the thresholdinput energy nearly equaled 20 J. We propose a new mathematical modelfor the PTC in the fault current condition, a PTC-TACS (Transient Analysis of Control Systems) model, by using the Electro-Magnetic Transient Program (EMTP), which is a function of the input joule heatingenergy. A comparison between the experimental results and EMTPsimulation results has shown that the PTC-TACS model is valid and veryeffective to investigate the PTC under fault current conditions inelectrical circuits and to design an over-current limiter based on PTCmaterials for industrial applications. In the discussion about radiationpower loss in case that the applied voltage is greater than 50V or thetripped time is less than 4ms, it is shown that the radiation powerloss can be neglected and the PTC resistance can be expressed only bythe input joule heating energy.

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Experimental and numerical studies of erosion process of an MgO layer were performed in order to obtain a fundamental guideline for lifetime evaluation of a plasma display panel (PDP). From the experimental results of an over-voltage accelerated discharge test and surface analysis of the MgO layer, it was found that the erosion and deterioration progressed due to the bombarding ions and adsorbed impurities, respectively, in the MgO surface during the accelerated discharge. The numerical analysis of the plasma behavior and its structure in PDP discharge was performed to explain these experimental results. The localized erosion on the MgO surface was due to the discontinuity of the ion bombardment, which was further expedited by the charge accumulated in dielectric (wall charge) behavior. The combination of these behaviors of charge particle was found to explain the localized erosion process in the MgO layer in the accelerated PDP discharge.

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We have observed the co-seismic electromagnetic phenomena such as earth potential difference (EPD) variation and atmospheric electricity (AE) variation at three observation sites in Akita Prefecture. In the strong earthquake of December 2nd, 2001, we observed clear signals of the EPD and the AE variation at all three sites. However, the amplitude of both observed signals at three sites are very different though with almost equal quake intensity at each site. The AE signal amplitude is increasing with the EPD signal one at each site. The model how both variation signals appear is proposed to explain the observed data.

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Direct water-treatment method by O and OH radicals has been developed using DC driven atmospheric micro-plasmas operated in fast gas flow conditions. Over atmospheric pressure gas of pure oxygen, moist oxygen or water vapor passed through a small cavity of 200 μm in diameter where micro-plasmas were generated. The resident time of the feed gas within the cavity was around microsecond. The emission spectra of OH radical were observed. The oxidizing effects depend on the gas flow rate from the decolorizing rate for a food color. In comparison with the ozone decolorization, the fast gas-flow conditions are inevitable for utilizing short-lived radicals such as O and OH, to react with the water directly.

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Measurement of photoionization current is carried out in N₂/O₂ mixtures using a gas cell, which is made up an eccentric cylinder electrode. A deuterium discharge lamp with MgF₂ window is used for vacuum ultraviolet source. The photon energy of the VUV is changed by CaF₂ and quartz filters. The photoelectron current emitted from the surface of electrodes is observed in pure N₂ gas. On the contrast, it is confirmed that photoionization current increased in the gas cell with an increase in the partial pressure of O₂ in N₂/O₂ mixtures. Such current is also found in UV region. These facts prove certain generation processes of charged particles by photo ionization of NO which is formed through the recombination from dissociated O and N atoms by the VUV absorption. However, another result suggests a possibility of a certain charged particle production process through the interaction between N₂ and photodissociated O atom.

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This paper describes high frequency current identification of a micro strip line by non-contact measurement of magnetic fields. At first, three-dimensional FDTD simulation is applied to calculation of electromagnetic fields around a micro strip line. And, a current distribution is obtained from numerically rotational calculus of magnetic fields. Second, current identifications in micro strip line are simulated by means of the high frequency current distribution model. Third, the magnetic fields on practical micro strip line are measured by using the miniature magnetic field probe. Then, the current distributions in the micro strip line are identified. As a result, experimental verifications show the validity of the FDTD analysis and current identification approach.

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Dynamic properties of a magnetic force control device using laminate composite of magnetostrictive and piezoelectric materials were investigated. The magnetic force control is based on the inverse magnetostrictive effect of a magnetostrictive material, whereby the variation of the magnetization of the material changed with an applied voltage on the piezoelectric material is converted to that of the magnetic force via magnetic circuits. In this paper, the admittance and flux/input voltage of the device and a conventional electromagnet were measured by an impedance analyzer and compared in a frequency domain. The comparison demonstrates that the bandwidth of the flux of the device is high due to the small influence of eddy currents. A FEM calculation of the modal shape of the composite also explains the co-relation between the vibration of the composite and flux and the resonances of the flux occurred at the same resonance frequencies in admittance are attributed to the amplification of the strain of the magnetostrictive material.

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The effect of far-infrared radiation on cationic polymerization of epoxy resin was studied by thermal quantitative analysis. We use titanium oxide and aluminium oxide as ceramics for low temperature radiation. The absorption spectrum of epoxy resin depicts far infrared absorption from 6.6 to 16 μm. The radiation intensity spectrum of these ceramics were measured using black body standard. Radiation intensity absorbed by epoxy resin was much higher at aluminium oxide than titanium oxide. We performed cationic polymerization of epoxy resin and monitored thermal input and output by differential scanning calorimetry (DSC) using a ceramics coated DSC aluminium pan. Reaction initiation and termination temperatures of polymerization were nearly the same with or without ceramics. The reaction rate was maximal with aluminium oxide, however. We also tested polymerization of epoxy resin after mixing with 1% w/v of ceramics. The relative proportions of aluminium oxide and titanium oxide were varied. DSC measurements showed that the reaction energy of polymerization decreased after addition of ceramic. The decline was more pronounced with increasing aluminum oxide concentrations. For practical application of far-infrared radiation to epoxy resin polymerization, we studied LED encapsulation.

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We demonstrate high-efficiency white electrophosphorescence in organic light emitting diodes (OLED) employing blue and red phosphorescent molecules. As an emitting layer, bis[2-(4,6-difluorophenyl)pyridinato- N,C^2’] iridium picolinate (FIrpic) as blue and bis[2-(2’-benzo[4,5-a]thienyl)pyridinato-N,C^3’]iridium (acetylacetonate) [Btp₂Ir(acac)] as red phosphors were doped into a 4,4’-bis(9-carbazolyl)-2,2’-biphenyl (CBP) host. The OLED characteristics using multi-phosphors doped layers were studied. We focused on suppression of the color change with an increase of a current density while keeping high-efficiency. With an insertion of a 3 nm-thick 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) layer, high η_ext of 4.9±0.5% and pure white emission of CIE (0.32, 0.33) at 10 mA/cm² were achieved. Moreover, the color change with an increase of a current density was suppressed to a certain extent with in an insertion of other buffer layers, CBP and bis[N-(1-naphthyl)-N-phenyl]benzidine (α-NPD).

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We developed single-bent and double-bent graphite X-ray condenser devices by subjecting multiple layers of polyimide films to high-temperature graphitization. Polyimide film exhibited a complicated expanding or shrinking behavior in each of the pyrolysis and graphitization processes. We explained here the basic manufacturing process for polyimide film bending that avoided wrinkles through control of the heating/pressurizing process. The mosaic spread of the diffraction lines of graphite using this condenser device was in the order of 0.4 degrees, which enabled X-ray condensation by up to a factor of 10 times for a single-bent type condenser device and about 240 for a toroidal type condenser device.

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Recent rapid progress in nanotechnology has focused research and development efforts on new high performance materials. Organic-inorganic hybrid materials such as nylon-layered silicate nanocomposites have attracted special interest and various studies continue to be conducted on thermoplastic resins.
In this study, we found out the best organic modifier of layered silicate that contributed to an affinity for epoxy resin (thermosetting resin), and succeeded in creating an intercalated-type epoxy-layered silicate nanocomposite. This nanocomposite realized some improvements by the addition of 5 or 6 weight percentage of organically modified layered silicates, which have 20^oC higher thermal resistance, 60% higher fracture toughness, 19% higher flexural strength and 10% higher insulation breakdown strength than these of an epoxy resin without layered silicate fillers. An electrical treeing growth was observed in the nanocomposite. The electrical treeing progress with many branches in the nanocomposite seemed to result in an increase in the insulation breakdown strength. These results suggest the possibility of practical use as an insulating material in heavy apparatuses.

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Application of spherical triangles with the surface charge simulation method is examined. The spherical charge which, unlike the conventional curved triangle of the higher order, can exactly silmulate a spherical boundary, a commonly used interface in an industrial product. The spherical triangle was been used in charged hemi-spherical bounday and erros for potential and electric field were evaluated.

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Wrong:corecive force
Right:coercive force

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Wrong:deposite
Right:deposit

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Wrong:face-centerd-cubic
Right:face-centered-cubic

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Wrong:stracture
Right:structure

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Wrong:consists
Right:consist

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Wrong:pulse tansformer
Right:pulse transformer

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