電気学会論文誌A(基礎・材料・共通部門誌)
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
110 巻, 6 号
選択された号の論文の6件中1~6を表示しています
  • 野中 智, 柿元 章, 江藤 昭弘
    1990 年 110 巻 6 号 p. 337-345
    発行日: 1990/06/20
    公開日: 2008/07/15
    ジャーナル フリー
    A two-terminal micrometer electrode system of 30mm diameter for the rapid and easy measurements of dielectric constant and dissipation factor over a wide frequency range from 1kHz to 100MHz is presented.
    To minimize the error in the measurements of dielectric constant and dissipation factor caused by the uncertainty of the specimen's mean thickness determination, a specimen's mean thickness measuring mechanism is introduced to the electrode system having a shield ring, which was developed for the measurement of the solid plate specimen of less than 1.5mm thickness. To improve the sensitivity of the loss measurement at high frequencies around 100MHz and the stability of the electrode's Q at low frequencies around 1kHz, guarded variable capacitance diodes have taken place of a variable air capacitor which is in parallel with the electrode and is used to establish the resonance at any arbitrary electrode gap length. When the half-power varying-gap method which was developed by the authors is used, specimens having a mean thickness 0.5-1.5mm can be measured within about ±0.2% for the dielectric constant and about ±3% for the dissipation factor over the frequency range from 1kHz to 100MHz.
  • 坪井 始, 田中 始男, 内藤 督
    1990 年 110 巻 6 号 p. 346-355
    発行日: 1990/06/20
    公開日: 2008/07/15
    ジャーナル フリー
    In this paper, transient analysis of electric field is performed by the integral with time based on the formulation of boundary element method. When the equation of boundary element method is used for transient response analysis, the terms of the domain integrals is used for the formulation by substituting the unknowns on the boundary, and unknown variables are defined in the conductor regions because the domain integrals is unavoidable. Then the state equations for the variables in conductor regions are made and they are solved by the integration with time using eigenmodes.
    It is shown that the integrations with respect to time using the change of variable by eigenvalues and eigenmode give accurate solutions in comparison with step-by-step method because of the analytical integrations. Moreover, in the proposed method, numerical inverse Laplace transforms is not necessary, and the integrations with respect to time for the external condition which does not give Laplace transforms can be performed by numerical integrations. Non-conducting regions can be remove from the region to be analyzed and open boundary problems can be solved by the proposed method. The applicability of the method was verified by using one-dimensional and two-dimensional problems.
  • 鶴田 浩一
    1990 年 110 巻 6 号 p. 356-362
    発行日: 1990/06/20
    公開日: 2008/07/15
    ジャーナル フリー
    A Pyrex glass vacuum chamber was evacuated with an oil diffusion pump to a pressure of 3×10-4 Pa and CO2 or O2 gas was introduced into the chamber. The pressure of the introduced gas was maintained at a constant value between 10-3 Pa and 5×10-1 Pa for 2 or 4 minutes and pumped down once again to a vacuum of 3×10-4 Pa. After this, an impulse voltage slightly lower than the breakdown voltage of a test gap (0.2mm), was applied and the microdischarge (MD) current was measured.
    The onset of MD occurs when the applied impulse voltage exceeds a threshold voltage and the peak current of MD increases with increasing gas pressure introduced. But, there was no difference in the generation characteristics of MD between CO2 and O2 gas introduction. The components of the residual gas at after re-pump-out of the introduced gas were analyzed using a quadruple mass spectrometer. It was found there was no large difference in the components of the residual gas between CO2 and O2 introduction and the main component was H2O in both cases. As other components, N2, O2, H2, CO2, hydrocarbons and vacuum pump oil were also left.
    MD with large peak current over 4mA were measured only for the first application of the impulse and they for the subsequent applications were very small. A larger part of the adsorbed gas molecules on the electrodes desorbs together with the generation of the first MD. But the number of ions responsible for the first MD current was much less than the estimated total number of the adsorbed gas molecules on the effective area of the electrodes. Most of the adsorbed gas molecules was considered to desorb as neutral molecules.
    A model of MD was proposed to explain the experimental results as follows. The generation of MD requires multi-layers of gas molecules on the electrodes and a lot of gas molecules are released at one time by the bombardment of field emitted electrons or the stimulation of field desorbed ions. In the cloud of sufficient density of neutral gas, cumulative ionization by electron collision can occur and it transfers MD current.
  • 伊藤 晴雄, 井上 仁, 生田 信皓
    1990 年 110 巻 6 号 p. 363-371
    発行日: 1990/06/20
    公開日: 2008/07/15
    ジャーナル フリー
    A Monte-Carlo simulation for the photoelectron current behaviour is carried out to understand the measured anode current between parallel plane electrodes in vacuum which requires more than +20V before it saturates. In order to reproduce such a gradual staturation characteristics, elastic and inelastic reflection of electrons at the surface of electrodes have to be introduced with appropriate incident energy and angle dependences.
    The result of the simulation shows that the electron reflection at the electrode is essential to obtain realistic current-voltage characteristics in vacuum, where the most of electrons have to be reflected several times before entering the anode.
  • 所 哲郎, 遠山 和之, 田草川 守, 長尾 雅行, 小崎 正光
    1990 年 110 巻 6 号 p. 372-378
    発行日: 1990/06/20
    公開日: 2008/07/15
    ジャーナル フリー
    Non-polar polymers are widely used as electrical insulation materials. Their operating conditions sometimes become high electric field and high temperature. Under these conditions the conduction loss is supposed to affect the dielectric properties and to make the ac dissipation factor (tan δ) increase. Therefore the high field dielectric properties of polymeric materials in high temperature region becomes very important.
    This paper describes high field dielectric properties of polypropylene films measured at 50Hz and 400Hz above room temperature with the new electrodes developed by authors. At low temperature, the high field tan δ is independent of the frequency of the applied field. However, at high temperature, the high field tan δ becomes almost inversely proportional to the frequency, namely, the conductivity is independent of the frequency. The theoretical analysis shows that the high field dielectric loss is governed by two processes: one is the loss which appear only under AC field and the other is conduction loss which appear also under DC field. The latter loss becomes prominent under high electric field at high temperature.
  • 長田 正義
    1990 年 110 巻 6 号 p. 379-380
    発行日: 1990/06/20
    公開日: 2008/07/15
    ジャーナル フリー
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