A laminated and plane-welded electrical steel (LPW) is made in the way that laminated electrical steel sheets plated with Cu and/or Sn are heated in order to fuse the plated Cu andSn, weld the sheets at the surfaces and then combined them together. The LPW has a higher permeability than usual electrical steel plates and a higher electric conductivity than laminated electrical steel sheets. The mechanical strength of LPW is as high as those of electrical steel plates. The 2-dimensionally free shape of LPW is made by punching before welding the sheets at the surfaces. If LPW is used in a voice coil motor (VCM). the size of VCM is small, and the characteristcs of VCM are more improved if the LPW is made of grain-oriented electrcal steels and the easy axises are arranged along the magnetic path of VCM.

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In a motor with transformer function (MTF), where a magnetic core is used jointly as a motor core and a transformer core, the interactions between motor action and transformer one are investigeted in noload conditions. If flux densities are not saturated and magnetic circuits are balanced in the magnetic core, the characteristics of motor actions and those of transformer actions are almost independent each other. In motor actions, torques and iron losses are almost constant at frequencies different from transformer frequency, although they fluctuate at the same frequency. In transformer actions, exciting currents and iron losses increase although the increases are small at frequencies different from motor frequency. Thus a MTF drives almost individuals as a motor and a transformer in the same time.

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This paper describes a novel linear actuator with flat-ring-shaped permanent magnets. A pair of flat-ring-shaped Nd-Fe-B magnets having N and S poles on the surface are put on the same axis and facing each other. By rotating one of the magnets in the direction of its circumference, a rotational field having the direction of the axis occurs and makes a reciprocating force on the other magnet. When this magnet is restricted to linear motion along the axis, the mechanical energy driving the rotating magnet is transferred to the linear motion energy. A pump is made with this mechanism.

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The inverse problems are classified into two major categories, i. e. one is the inverse parameter problem; the other is the inverse source problem. Generally, the inverse problems are reduced into solving an ill-posed system of equations. This article proposes a novel approach for the inverse problems employing the wavelet analysis. Key idea is that the system matrix of the inverse problems is regarded as two-dimensional signal data. The two-dimensional wavelet transform is applied to this system matrix. Finally, an approximate inverse matrix of the system is obtained. We apply our approach to examples of both the inverse source and parameter problems. Simple examples demonstrate the validity of our approach.

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In the present paper, we propose a wavelet analysis technique to evaluate the noise filtering characteristics of the filter. To analyse noise problem, many people have used Fourier analysis. But the Fourier spectrum reveals only the frequency information. Therefore, it is difficult to obtain the noise waveforms from the Fourier spectrum. To overcome this difficulty, we employed the wavelet analysis technique. Wavelet analysis makes it possible to get the time as well as frequency domain information. As a result, it was shown that the wavelet analysis was one of the promising methodologies for noise filter characteristic evaluation.

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Over the past few years, a large number of studies have been made on inductors and transformers for micro do-to-dc converters which will be used in personal phones, card-type electronic devices etc.
A planar parametric transformer, which has already been proposed by us, has various desirable features including voltage regulation, overload protection, and noise rejection. The transformer is formed of a stack of five Amorphous Fe₅Co₇0Si₁₅B₁₀ alloy 0.03mm-thick laminations fabricated by the wire-electric discharge machine, and is composed of a magnetic path with three legs and end bars connecting the ends of those legs. Slots are made in the centers of the outside edges of the end bars, to prevent the magnetic flux in each side leg from entering the other side leg. These slots cause a parametric oscillation in the transformer.
This paper discusses the fundamental performance characteristics of a 5mm×7mm sized transformer, and studies the conditions for generating parametric oscillations in a planar transformer, in order to make clear the operational mechanism of the transformer. This paper also studies the effects of the width of the center leg and the position of the windings, which are very important design factors of the transformer.

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A novel zero-voltage-switching current resonant converter is presented. The Rectifiers' Deadtime Technique proposed in this paper enables this converter to achieve zero-voltage-switching on all semiconductor devices including rectifier diodes in any load range and to operate from full load to no load within a high and narrow frequency range. The circuit operation is analyzed and it is verified experimentally by two converters designed for 1MHz and 10MHz switching frequency operation. In the experiments, the zero-voltage-switching is achieved in even light and no load and the maximum efficiency of 93.5% at the 1MHz-class converter and that of 85.2% at the 10MHz-class is realized.

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Nickel chromium molybdenum steel shafts (SNCM) for a magnetostrictive torque sensor were evaluated for such items as sensitivity, hysteresis and zero-level-fluctuation. Magnetic inhomogeneities of the steel shafts were also evaluated in terms of magnetic anisotropy at the surface of the shaft. It was found that the lowest hysteresis was obtained with a carburized SNCM420 shaft. The linearity measured with this shaft was as good as 0.8%/(full scale) (full scale=1000Nm for a shaft of 25mm in diameter). Zero-level-fluctuations of the torque sensor using SNCM420 carburized shafts were not so large compared with those using as-ground shafts despite of reduction of the sensitivity. This was because a peculiar magnetic anisotropy pattern at the surface of the shaft without heat treatment was erased and uniformed by carburizing.

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In this paper, the performance analysis of the orthogonal-core type power converters have been developed by the use of a new network analysis, in which the reluctance network of an orthogonal-core and the outer electric circuits coupled with each other. According to the method, the performance analysis of the converter is carried out easily and speedy under the consideration of the orthogonal-core flux distributions. The results are possibly applied to the circuit analysis included semiconductor elements and transient phenomena. Therefore the method in this paper is very useful for the anlysis and design of the orihogonal-core type power converters.

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So far, spectral analysis method based on fourier transform is used to analyze electromagnetic emission or conductive emission noise from PCB (Printing Circuit Board) of electronic equipments. But recently time domain analysis is required in order to provide waveform information which gives clock timing and waveform transmission characteristics. One of the problems in analyzing waveform in time domain is synchronous failure because of nonstationary nature of the noise included. In this paper, the discrete wavelet transform and correlation calculations are applied, as a low pass digital filter, to extract voltage descent of power terminal of a Pentium CPU from noisy waveform. Further it became possible to make synchronous addition for reducing amplitude of random noise.

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Teruyoshi Mizutani, Member (Nagoya University) Spiropyran (SP18 and SP1822) films were prepared by the Langmuir Blodgett method, and the relations among the preparation condition, the film structure and the optical properties such as the UV-visible absorption and the third-order nonlinearity were investigated The AFM images showed that the surfaces of spiropyran LB films prepared by adding proper amount of arachidic acid and n-octadecane were smooth, indicating that the structures of these films were successfully controlled. The third-order nonlinear optical susceptibility was measured using the third harmonic generation method The reversible change in third-order susceptibility corresponding to photo is omerization of spimpyran was observed from these LB films. The absorption spectra of the films annealed at temperture 35°C after UV irradiation showed that J aggregates were formed in the case of SP1822 but not in the case of SP18, suggesting that the J aggregate formation depends on the stability of photomerocyanine state due to the additional alkyl chain.

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As a fundamental research of corona preionization of a discharge-pumped KrF excimer laser, electrons produced by ultra violet light from a surface corona discharge on the planar ceramics of SrTiO₃ of 6800 of dielectric constant, are estimated for the applied voltage of 5 to 20kV under the conditions of Kr:He=1:99% at the pressure of 3atm. An electron drift current is measured at the gap apart from 10mm from the corona source for 1kV of applied voltage. It is a feature that plural needle electrodes are employed for efficient production of electrons. The observed corona current by the needle-plane electrode system reaches over 200A of the peak current of a sinusoidal waveform and increases with the applied voltage. The electron density in the order of 10⁸ to 10⁹cm^-3 is obtained, of which density is larger by about 20% than the case of an arc discharge at 20kV of charging voltage. It is found that the surface corona discharge occurred by the needle electrodes on a glass plate of a low dielectric constant does not reach a sufficient electron density for the preionization. A slit configuration of the electrodes on the ceramics of 6800 of dielectric constant does not bring a satisfied electrons either. It means that the large corona current should be flown concentratedly for obtaining a strong preionization. The electron density in the excimer laser gases of Kr/F₂/He is calculated based on the results of Kr/He gas mixtures by using a rate equation in which the electron attachment of fluorine gas is considered. It is found that the electron density of the order of 10⁶cm^-3 is obtained, which is considered to be enough to generate a stable glow-like pumping discharge for the excimer laser.

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The inter-glow-arc flip-flop transition, we call, occurs between glow and arc discharges even in the normal glow region. Here voltages succeedingly jump up and down and jump up and down at the nearly same current. It appears, authors found, as continual bursts. We became early aware of this fact but recently the measurement assisted by PC and GP-IB has enabled us quantitatively to ascertain it. The investigation was conducted on Ag electrodes in atmospheric air as it delivered a typical example. In this paper the matter how the bursts influence the measured values of this transition is presented and discussed.

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In this paper the authors discuss their research on heat generation of electric contacts named "Hot-zone phenomenon". When a large electric current flows in an electric wire jointing section of abnormal conditions, the temperature of the section rises and subsequently causes an electric fire. We have previously observed this Hot-zone phenomenon and explained the growth mechanism of the condition in an A. C. circuit. In this paper we have conducted experiments on the conditions of a D. C. circuit of about 12 working voltage using copper electric wires. The experiments were carried out by observing abnormal conditions caused by the opening and closing action at the electric wire jointing section. The growth mechanisms of the Hot-zone phenomena were then explained more precisely. The results obtained agreed approximately with those of an A. C. circuit as expected.

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We are now long developing the extruded EPR insulated DC superconducting cable. Since polymeric insulators often fail due to treeing breakdown, it is imperative to study the treeing resistivity of EPR to evaluate long term reliability as a cable insulator. In this paper, we have studied dc short-circuit treeing resistivity of EPR both at liquid nitrogen temperature and at room temperature to elucidate space charge behaviors in this insulator at cryogenic temperature. The results show that the short-circuit tree initiation voltage at cryogenic temperature is much higher than that at room temperature. This may be attributed to less carrier injection from electrode and higher electric strength of EPR at cryogenic temperature. Space charge measurement was carried out using pulsed electroacoustic method. At room temperature, negative space charge is injected from the cathode, but at cryogenic temperature the injection is very limited. For dc electrical insulation, space charge is less problematic at cryogenic temperature than at room temperature.

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The C₆₀-Polyisothianaphthene (PITN) heterojunction device was fabricated and its electrical and photoiradiation effects have been investigated. This device shows remarkable rectifying action. The photovoltaic effect and the anomalous polarity effect of photoconduction in C₆₀-PITN layer were also observed. Its photoresponse gives evidence of the photoinduced charge transfer between C₆₀ and PITN. These results are discussed by taking account the difference in electronic states of both C₆₀ and PITN.

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This paper deals with the partial discharge measurement in liquid nitrogen immersed insulation using high frequency detection system.
AC voltage of 3-6kV were applied on a needle-plane electrode system in which a polyethylene terephthalate film was inserted. Partial discharge detection was carried out using a wide band current detection system that has a frequency range up to 250MHz. The magnitude and pulse width showed significant differences depending on the polarity of pulse current when the applied voltage was high.
Frequency analysis was done in both low and high frequency bands. It was found that the signal component within 150-250MHz had a correlation with the discharge mode. The signal component within 1-10MHz had a correlation with PD charge magnitude.
Based on the above results, the partial discharge measurement with high frequency range is suggested to be effective for the monitoring of discharge mode.

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