IEEJ Transactions on Fundamentals and Materials
Online ISSN : 1347-5533
Print ISSN : 0385-4205
ISSN-L : 0385-4205
Volume 115, Issue 11
Displaying 1-17 of 17 articles from this issue
  • Eisuke Tokumitsu
    1995 Volume 115 Issue 11 Pages 1043-1049
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
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  • Yuan-shing Liu, Takehiko Mizuno, Manabu Saijyo, Shozo Ishii
    1995 Volume 115 Issue 11 Pages 1050-1056
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Electron-beam induced heating within solid targets of high atomic number Z such as Ta and W in x-ray sources is investigated with a method of numerical analysis. The depth-dose curve for pulsed electron beams of energy ranging from 5 to 50 keV is calculated by using the Monte Carlo method. From the depth-dose curves, the projected range as a function of beam energy is determined by means of analytical expressions in the limited range of 73_??_Z_??_74. A volume heat source in the heat diffusion equation can be written in terms of the projected range and a normalized Grun function. The normalized Grun function is expressed by a polynomial which can be calcuated by a balanced reationship of the incident beam energy density. The heat diffusion equation has been appield to numerically calculate temperature profiles within the targets as a function of time. The results can be used to determine the maximum surface temperture and the thickness of melted targats for different incident energy densities. Usefulness of these results in manufacturing processes using electron-beam heating such as hardening, cutting and welding has been pointed out.
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  • Hirofumi Takikawa, Ryuichi Miyano, Tateki Sakakibara
    1995 Volume 115 Issue 11 Pages 1057-1061
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    The appearance of discharge near the cathode surface in a vacuum-arc-deposition apparatus is observed when the pressure is increased gradually from 0.1 to 100Pa, with applied voltage held at DC 1, 180V. The result shows that the glow discharge appears at pressures above 1Pa, and then changes to arc discharge. This phenomenon is explained by the glow-to-arc transition mechanism due to the increase of the discharge current.
    Arc transition probability is measured as a function of pressure (0.01-100Pa) with constant applied voltages of 590 and 1, 180V, the cathode materials being Al, Ti, and C, and the introducing gases being Ar and N2. The result shows that (1) the arc transition occurs at higher pressure and with higher applied voltage. (2) The transition with Al cathode occurs at lower pressure than with Ti cathode. (3) The transition N2 gas occurs at lower pressure than in Ar gas.
    The influence of cathode material in Ar gas on the arc transition probability is qualitatively interpreted by comparing the melting points of the materials. The influence in N2 gas is qualitatively interpreted by examining whether a compound grows on cathode surface or not, and whether the compound is electrically conductive or not.
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  • Mitio Iemura, Itaru Nakamura, Masaaki Kurosumi, Junichi Yamaguchi
    1995 Volume 115 Issue 11 Pages 1062-1071
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Concerning the operating circuit for high pressure mercury arc lamp, the authors propose a in-phase type operating circuit through which current, nearly sinusoidal, runs with power factor, close to 100%. We connect by-pass circuit to the tap at the point near power source side, using ballast with larger self-inductance than self-inductance L of ballast winding of operating circuit without by-pass circuit. It is shown that in-phase type operating circuit, through which sinusoidal current runs in power source side with power factor of 100%, is realizable, by fixing the circuit constant with self-inductance L, self-inductance of choke coil of by-pass circuit Lb and condenser capacity Cb at reasonable value.
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  • Tetsuya Fujimoto, Haruo Itoh, Tomonao Hayashi, Nobuaki Ikuta
    1995 Volume 115 Issue 11 Pages 1072-1077
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Low reflectance surface for electrons is formed using electrostatic flocking of carbon fiber piles. Carbon piles are vertically fixed on an aluminium plate by the epoxy resin mixed with carbon black. The reflection coefficient of the flocking surface is measured to be 0.2 in the energy range of 5-15eV. This value is about 50% compared to ordinaly metal (Al, Au, etc) surface. The reflection coefficient of flocking surface to electrons is lower than that of the surface covered with soot.
    In this paper, we describe at first the formation method of flocking surface in briefly. And we also reports the result on the experiment for reflection coefficient at the surfaces include the flocking one.
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  • Hiroyuki Hama, Kiyoshi Inami, Manabu Yoshimura, Koichiro Nakanishi
    1995 Volume 115 Issue 11 Pages 1078-1087
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    In the present report the authors propose the method to estimate the minimum breakdown voltages of surface flashovers initiated from the triple junction at which a solid insulator, SF6 gas and a metal electrode come in contact.
    Using four kinds of test samples, we have measured the flashover voltages Vf. The voltages Vf become lower than the theoretical voltages Vs of streamer inception in the case of the test sample with the large electrode area at the triple junction. To understand the phenomena quantitatively, we estimated the real partial discharge voltages Vc from the voltages Vf, and investigated the relationship between the voltages Vc and the theoretical values Vs. The values of Vs/Vc, which characterize the properties of the partial discharges, can be shown by the product λ S90%EavP of the following parameters; (1) coefficient λ representing the surface roughness of electrode at the triple junction, (2) effective area S90% of the electrode, (3) average field Eav at the area S90%, and (4) gas pressure P. The minimum surface flashover voltages in the insulators for coaxial electrode systems can be estimated precisely, considering the properties of Vs/Vc.
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  • Mengu Cho, Koji Masutomi, Hiromasa Takeno, Kenji Arai
    1995 Volume 115 Issue 11 Pages 1088-1097
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Computer simulation is carried out to study the propagation processes of blast wave induced by laser-produced plasma in air. One-dimensional Euler equation is solved numerically by a finite discrete method. Real gas effects are taken into account based on the assumption of local-thermodynamic equilibrium (LTE) where the electron and heavy particle temperatures are assumed the same and the chemical equilibrium holds at every point. Rarefied gas region is formed between the shock wave front and the plasma core, and the plasma core decays at the time scale of msec. In order to examine the validity of the LTE assumption, the radiation spectrum from the plasma core is calculated and compared with the experimental data. The simulation code underestimates the electron temperature and density during 10μsec after the laser plasma ignition because in reality the electron temperature is still higher than the heavy particle temperature. However, as the plasma approaches the equilibrium state after 10μsec, the simulation results show a good agreement even quantitatively with the experimental results.
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  • Satoshi Tomioka, Makoto Kagata, Hiroyasu Itoh, Shusuke Nisiyama, Takea ...
    1995 Volume 115 Issue 11 Pages 1098-1104
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
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    The inhomogeneous term in boundary element method (BEM) analysis is expressed by domain integration. This domain integration reduces the merits of BEM, which are small memory usage and low cost for calculation time.
    We show a new approach for transformation of the inhomogeneous term from domain integration into boundary integration, using the Helmholtz equation containing an inhomogeneous wave number (such as in a plasma with spatial density distribution). We attempt the correction from the fundamental solution of a homogeneous medium to that of an inhomogeneous medium by considering the phase distance between source and observation point and amplitude of energy in traveling that distance.
    In an inhomogeneous medium, the path of the wavelet is bent by the space distribution of the refraction index, in order to satisfy the Snell law of refraction or Fermat's principle.
    The phase distance is calculated by the integration along this bent path. The energy flux density of a traveling wavelet is treated as isotropic in the neighborhood of the source points. However it is not uniform at the observation point because of bent paths. We calculate the energy flux density at the observation point considering the angle of radiation at the source point. These corrections lead to a boundary integral equation without the domain integral.
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  • Yuji Okunaga, Shigeru Sasabe, Masato Arai
    1995 Volume 115 Issue 11 Pages 1105-1113
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    It was shown in the previous work (T. IEE Japan, 113-A, 719, (1993)) that the electron, which is in fact a structureless point particle with its self-field, behaves as if it has virtual charge distribution when it interacts with the Coulomb potential fixed in a space. In this paper, it is proved that in general the virtual charge distribution appears for the electron interacting with an arbitrary physical potential as well as the Coulomb potential. Next, we consider an electron that obeys the classical Lorentz-Dirac equation (i. e., L-D electron). We investigate the relation between the force on the charged particle and the wavelength of the electromagnetic wave in the two cases; one is the case of L-D electron, and the other an extended charge of classical electron radius. We see that L-D electron is more similar to the extended charged particle than the structureless electron. So we can find some virtual structure. As a result, we conclude the equivalence of the point electron with its self-field and the charged particle having a virtual charge distribution.
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  • Nobukazu Inoue, Kazuhito Yamasawa
    1995 Volume 115 Issue 11 Pages 1114-1120
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Bi-doped garnet is a rare metal iron garnet made up of a ferrimagnetic substance of which some part of rare metal element is replaced with Bismuth. It illustrates a strong Faraday effect and has been applied to optical isolators. In magnetic field sensing applications, however, a shortcoming is apparent: Faraday rotation of Bi-doped garnet reveals temperature dependencies when the garnet is not magnetically saturated. Authors have paid close attention to the magnetization of each rare earth element's different temperature characteristics, and have been investigating compositions of garnets by calculations and experiments to find a garnet showing flat temperature characteristics between -10 and 80 °C. The LPE(Liquid Phase Epitaxy) method was established to get a single crystal of the garnet {Bi1.3(Y, La)0.9Ho0.8Fe4.5Ga0.5O12}. A magnetic field sensor of fiber optic based on the Faraday effect of this single crystal can detect conductor currents of power cables with high accuracy. The developed sensor is small and lightweight compared to conventional current transformers, and has the quality that optical fiber transmission of detected current signals is free from electric and magnetic noises.
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  • Suwamo, Yasuo Suzuoki, Teruyoshi Mizutani, Katsumi Uchida
    1995 Volume 115 Issue 11 Pages 1121-1129
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Partial discharges (PD) pulses from electrical treeing in low-density polyethylene with a needleplane electrode system were observed by using a computer-aided partial discharge measurement system. Simultaneously the tree shape was observed optically, and the correlation between the tree shape and the PD pattern was investigated. Unlike the magnitude of PD pulses originating from a void, the magnitude of PD pulses originating from tree path increased with the phase angle of applied voltage (the wing-like pattern) and the PD pulse number in every half cycle was less than the number of tree trunks and much less than the branch number. These facts and the one-cycle pulse-sequence analysis suggested the following: (1) each PD pulse in every half cycle originates from a different discharge path which is connected to the needle electrode; (2) at most one discharge takes place in each discharge path in every half cycle. By applying a pattern recognition technique to the wing-like pattern, the tree shape was successfully assessed.
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  • Masasumi Yoshizawa, Eiki Watanabe, Tadashi Moriya
    1995 Volume 115 Issue 11 Pages 1130-1136
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
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    The method to visualize an electrical treeing region in translucent or opaque electrical insulating materials by using ultrasound with a center frequency around 20MHz is presented.
    The dependence of the spatial resolution on the frequency of ultrasound is investigated by means of actual measurements of velocity and attenuation of ultrasound for the test materials. On the basis of the results, sufficient resolution and intensity for the ultrasound echo signal reflected from the electrical tree are obtained by selecting the transducer with an appropriate center frequency to emphases the higher region of the frequency, and also by utilizing a Boxcar integrator for improving signal-to-noise ratio.
    As the results, it is shown that the branch type tree in polymethylpentene, the bush and the ball type ones in polyethylene can each be visualized. The shapes and the sizes are agreed with those obtained by optical inspections.
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  • Futao Kaneko, Syosaku Honda, Takashi Wakamatsu, Kazunari Shinbo, Keizo ...
    1995 Volume 115 Issue 11 Pages 1137-1143
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Attenuated total reflection (ATR) properties have been investigated as a function of incident angles of visible laser beams for LB ultrathin films of arachidic cadmium salt on Ag and Al thin films. The ATR properties are measured for the LB ultrathin films with different numbers of the monolayers. The resonance angles for both the LB films on Ag and Al films strongly depend upon the number of the monolayers. The calculated ATR curves fit the experimental ones, assuming that the complex dielectric constants are isotropic and constant for all LB films. The thicknesses of the LB monolayers are decided from the theoretical curves. The result shows that the deposition of the LB films on Al films is better than the one on Ag films. The ATR measurement has not been reported for LB films on Al films until now. It is thought that the ATR measurement for LB films on Al films is very useful because most LB films are easily deposited on Al thin films.
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  • Ryu Wakamatsu, Tamiya Fujiwara, Hiroshi Yamada, Kuniyuki Goto, Katsuto ...
    1995 Volume 115 Issue 11 Pages 1144-1150
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    Branching structure of negative streamer in liquid dielectrics is found to have fractal characteristics. The fractal dimension of negative streamer in liquid dielectrics is constant during voltage application period, which also has been reported for several solid dielectrics. In case of the mixtures of hydrocarbon liquids and carbon tetrachloride, the fractal dimension decreases as the aspect of negative streamer is changed from bush-like one to tree-like one. The patterns of negative streamer aspects obtained from the simulation are compared with those obtained from the experiment.
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  • Koji Urano, Yoshiyasu Ehara, Haruo Kishida, Tairo Ito
    1995 Volume 115 Issue 11 Pages 1151-1156
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    This research is carried out to analyze the treeing phenomena with a needle shaped void by the discharge magnitude and the luminous intensity distribution in each phase angle area at the same time. The discharge pulses and discharge luminescence are measured by the special measurement system for measuring the discharge magnitude and discharge luminous image according to several phase angle areas of applied voltage. Each phase angle area was named φ1-20 in order from the negative peak point of applied voltage. The luminous image was digitized with a computer after the experiment. In particular, in this study, we focused on the discharge luminous intensity distribution in each phase angle area. The results show that the discharge magnitude significantly correlates with the luminous quantity at the tree area in φ8 and φ18. Therefore, the quantities of partial discharge at the φ8 and φ18 phase angle area are considered to be more useful information for a diagnostic technique of the deteriorating condition of electrical treeing.
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  • Takao Tsurimoto, Masayuki Nagao, Yukio Mizuno, Masamitsu Kosaki
    1995 Volume 115 Issue 11 Pages 1157-1161
    Published: October 20, 1995
    Released on J-STAGE: July 15, 2008
    JOURNAL FREE ACCESS
    In the electrode system without epoxy molding, it is supposed that dielectric breakdown of polymeric insulating films under dc voltage in a room temperature region is caused by the positive feedback process of localized electro-mechanical deformation and Joule heating at weak points distributed in films. Under ac voltage application, localized heat generation of low-density polyethylene (LDPE) film leading to dielectric breakdown was scarcely detected. However, considering that (1) the ac breakdown strength is lower than the dc one, where high temperature point leading to dielectric breakdown was detected and (2) ac breakdown strength was affected by rise rate of applied voltage, ambient medium and type of applied voltage, it is suspected that thermal process must be involved in ac dielectric breakdown of LDPE film at a weak point distributed in the film in a very short time range within the time resolution of thermograph.
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  • 1995 Volume 115 Issue 11 Pages 1169
    Published: 1995
    Released on J-STAGE: March 23, 2011
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