This paper describes on a new type of the fault locating method by using voltage and current values measured in a substation or transmission lines. This new type fault locating method is based on impedance method. This newtype fault locating method consists of the following items.
(1) Analysis of harmonic components in voltage wave forms measured in the substation.
(2) Estimation of the arc fault voltage on the lines.
(3) Calculation of the line impedance voltage drop.
(4) Determination of the fault locating distance.
The avilability of this method was confirmed by arc fault tests on 6kV cable and overhead distribution lines. As a result, the fault locating error of this method was proved to be roughly less than 10%.

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The vector potential in electrodynamics is investigated through the decomposition of its form to the following two parts; the one is the so-called transverse part represented by a divergenceless vector and the other the longitudinal part represented by an irrotational vector. The decomposition can be done by the Helmholtz theorem in the vector analysis because the conditions which should be required when we use the Helmholtz theorem are satisfied for the almost vector potentials of physically interesting problems. As an example of such interesting problems, we choose here the Aharonov-Bohm effect. As for the Aharonov-Bohm effect, the vector potential given in the original paper of Aharonov and Bohm has the singularities along the z-axis. We show that even for such a singular potential the Helmholtz theorem is held provided that the concept of the distribution is introduced in it. Generally, the transverse part of the vector potential obtained through such a decomposition is uniquely determined by the magnetic field and does not alter by a gauge transformation, on the other hand, the longitudinal part depends on the choice of special gauge. We show that the Aharonov-Bohm effect is due to the contribution of the transverse part of the vector potential and therefore should not be influenced by any gauge transformations.

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When partial discharge (PD) was measured with the conventional pulse method, it sometimes apparently disappeared. However, it turned out that, in many cases the PD did not actually disappear, but only became a large number of very small partial discharges known as swarming pulsive microdischarges (SPMD). After this silent stage, PD appeared again, leading to final breakdown. Since SPMD are missed in the conventional PD detection, it is necessary to pay careful attention to SPMD in terms of insulation diagnosis. The authors developed a personal-computeraided partial discharge analyzing system for SPMD measurement. The system has two detection methods for partial discharge measurement: a conventional pulse charge method and a balanced Lissajous figure method. The former failed to detect SPMD due to the sensitivity limit of the detector, while the latter integrated all charges including SPMD per half cycle. Therefore, the difference between the charge integrals of partial discharges per half cycle measured -by these two methods must be a good measure of SPMD. Based on this idea, a new parameter, the SPMD ratio, was introduced. Using the developed system and the new parameter, partial discharge characteristics were studied for the CIGRE method-II specimen with internal void, in order to examine the factors affecting the appearance of SPMD. From the experiments, it became clear that there are two kind of factors to induce SPMD with or without the relation to the partial discharge degradation.

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The piezoelectric constants and propagation characteristics of shear horizontal (SH) waves in a PbZrO₃-based ceramic substrate are described. Numerical analysis for the phase velocity of SH waves is carried out under various electrical and mechanical boundary conditions. The results confirmed experimentally are given in the form of a function of the product of the frequency and the substrate thickness, which suggest that the zeroth-order symmetrical (S₀) mode is promising for the device construction because of high electromechanical coupling and low dispersive property. The So mode device is in a single mode operation in a considerably wide frequency range, which is suitable for constructing a stable oscillator. A delay line oscillator is composed of the So mode device, an amplifier and an electrically controllable phase shifter, of which oscillation frequency varies with the applied voltage. The oscillator has fine frequency modulation characteristics over a wide frequency range from DC to 100kHz. The device performance is useful for FM signal processing or voltage sensing.

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Moisture sensing mechanism in capacitive humidity sensors has been investigated in details. The infrared spectrometric analysis revealed that the water molecules were occluded in moisturesensitive films of CaF₂ and Al₂O₃ in liquid phase. They also were occluded in polymethyl methacrylate (PMMA) and cellulose triester (CTE) films in the form of rotationally restrained physisorbed water which has little interaction among them.
Relatively large hysteresis and/or complicated temperature dependence were observed in capacitance (C) vs. relative humidity (RH) characteristics for hydrogenated carbon containing oxygen (a-CHO), polyvinyl alcohol (PVA), PMMA, CaF₂ and Al₂O₃. On the other hand, temperature dependence and hysteresis in C vs. RH and MH2O (Mass of water which was taken in a unit volume of sensing part) vs. RH characteristics were scarcely observed for CTE.
The desirable properties for moisture-sensitive materials which can be used under a wide range of temperature and humidity are; (1) the heat of adsorption for the 1st layer of water molecules is equal to that of N-th (N>2) layer, (2) no internal water molecules condense and (3) the temperature coefficient of dielectric constant is negligibly small.

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In order to elucidate the influence of the bulk/electrode interface on the photocurrent in plasmapolymerized ethylene thin films, photoconduction characteristics in the visible wavelength region were studied. The photocurrent polarity differs between the illumination on the upper electrode and that on the lower electrode. From this result, together with the dependence of the photocurrent on the area of the illuminated electrode, it was found that the condition of the upper electrode/bulk interface differs from that of the lower electrode/bulk one, and that photo-injection of holes always occurs from the lower electrode. In the case of aluminum, the photocurrent rises and decreases more sharply with the illumination time than the case of gold electrode. These results suggest that the photo-injection of holes is suppressed by the surface oxidation layer of plasma-polymerized ethylene. Also found is that the Al₂O₃ layer on the aluminum electrode scarcely blocks the hole photoinjection, but localized states existing in the Al₂O₃ layer affect the temporal response of the photocurrent.
The photocurrent shows variety of responses depending on the wavelength of the illuminated light and the polarity of the applied field. These observed photocurrent waveforms can be simulated by combining three fundamental waveforms.

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Melt-spun ribbons of Nd-Pr-Fe-Co-B-V system alloys were prepared by the single roller rapidquenching method. The effects of composition, wheel velocity and heat-treatment on the magnetic properties were investigated. The magnetic properties of their isotropic compression bonded magnets prepared from optimally annealed ribbons were also measured. Remanence (Br) was found to increase with decreasing rare-earth content, and a maximum value of more than 1.0T was obtained. A maximum energy product of 164.0kJ/m₃ was obtained for (Nd0.5Pr0.5)9Fe74Co8B7.5V1.5 alloy ribbon prepared at a wheel velocity of 17.1m/s. From TEM observation, the particle size of these ribbons was determined to be between 20 to 30nm. It is conjectured that the high remanence is obtained by the interaction of these fine particles. The amorphous (Nd0.5Pr0.5)9Fe74Co8B7.5V1.5 ribbons prepared at a wheel velocity of 20.7m/s were crystalized by heat treatment, and the optimum annealing condition was found to be at 650°C for 20min. Its corresponding valueof. (BH)max was 146.2kJ/m₃. A maximum energy product of 86.4kJ/m₃ was achieved with (Nd0.5Pr0.5)9Fe74Co8B7.5V1.5 bonded magnets made from the optimally prepared ribbons.

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It is considered that electrical conduction in polymer in releatively low electric field is ionic. Here investigates about resistivity of ionic conduction and dielectric loss tangent for various polymer films.
Temperature dependence of resistivity is expressed by the following Arrhenius equation, ρ=ρo exp (E/RT), where ρ is the resistivity, ρo is a constant, E is the activation energy, R is a gas constant and T is the absolute temperature.
Usually, transport phenomena such as mobility, viscosity, diffusion and so on show a compensation effect. Ionic conduction in polymer is also shown a compensation effect equation as ρo=a exp (bE), where a and b are constants.
Polymer has properties of glass and rubber state below and above glass transition temperature. Although these states have each compensation effect, we find the compensation effect of three types. One is that of amorphous polymer such as PEI (Polyetherimide), the second is that of crystallized polymer such as PET (Polyethylene terephthalate), and the third is that of crystallized polymer above glass transition temperature.
In this study, an equation, which can calculate the activation energy of resistivity, is deduced by using compensation effect.

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