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Shinji Tazawa
2001 Volume 121 Issue 11 Pages
973-976
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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Noboru Masuda, Hiroshi Nakane
2001 Volume 121 Issue 11 Pages
977-983
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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Application of high brightness LED as the light source for colors to the electric display or lighting equipment is expected.
The simple circuit, which can handle from 1 to 10 LED of various colors driven in the most suitable state without changing a circuit constant, is proposed. We obtained how to mix varied colors emitted from LED, and the generation of patterns on indicator by the color materials such as ink and paint. We produced electric display experimentally in order to confirm visibility of color or luminosity of mixing of various colored light.
The display constituted with a light guide and indicator, a number of LED was installed in the side or in the backside of the light guide. Indicator is placed upon an upper side of the light guide. The letter, which was drawn on an indicator urface with green ink, twinkles by the luminous flux of LED of blue beautifully.
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Yoshio Higashiyama, Kenji Nagaki, Kyoko Yatsuzuka, Kazutoshi Asano
2001 Volume 121 Issue 11 Pages
984-989
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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To obtain mobility of air ions under atmospheric pressure conditions, a simple measuring method of drift veloc-ity of positive air ions produced by pulsed corona discharge was demonstrated. The drift region was formed by two disc electrodes. The ions were produced at the tip of a needle electrode where a high-voltage pulse with duration of 10 μs and pulse height of 3 kV was applied with repetition rate of 25 Hz. A time of flight of ions from the needle to an ring electrodes was obtained from the waveform of iuduction current due to movement of ions. There is zero-crossing in the waveform of the induction current. The zero-crossing time was detected automatically by a fabri-cated circuit and a counterboad connected to a personal computer. In this system, 400 data of the drift velocity of ions obtained for the period of 16 seconds were avaraged and ion mobility were calculated. The drift velocity of ions depends on the electric field strength in the drift region. The ion mobility under atmopheric pressure was obtained as 1.95×10
-4 m
2/V•s.
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Hideki UENO, Hiroaki MASUOKA, Hiroshi NAKAYAMA
2001 Volume 121 Issue 11 Pages
990-996
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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The flashover characteristics in Discharge Extension Behavior in Narrow Gap Filled with N
2/SF
6 Gas between Insulators gas mixtures for the needle-plane electrode configuration with an insulating barrier consisting of two separated insulators with a narrow gap, which is just below and along the needle electrode, have been investigated. The SF
6 gas content dependence of flashover voltage strongly depended on the gap width. And the reduction of flashover voltage by the addition of small amount of SF
6 gas was found for the wider gap width (_??_500um) under the gas pressure of 0.3MPa. Thus anomalous dependence of the flashover voltage should result in the change of the discharge extension path and its behavior in the narrow gap induced by the addition of SF
6 gas into N
2 gas.
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Masanori Ishii, Takashi Iwasaki
2001 Volume 121 Issue 11 Pages
997-1005
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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This paper presents a method for finding the two-dimensional direction of arrival (
DOA) of a single short pulse. The method is based on a waveform reconstruction using complex antenna factors (
CAFs) with incident angle dependence. In order to apply the technique to an arbitrary polarized pulse, three dipole antennas are adopted as an antenna system instead of two square loop antennas already reported. The results of a simulation and an experiment show the possibility to use the dipole array antenna in the two-dimensional DOA finding.
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Temperature rise calculation of cable protection pipe
Tsuguhiro Takahashi, Tetsuo Ito
2001 Volume 121 Issue 11 Pages
1006-1011
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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Information on heat conduction around an underground power cable system is required for exactly evaluating the allowable current in the system and furthermore for rationalizing its design and operation. A useful method, which is named the heat-source simulation method, is proposed for analyzing the heat conduction phenomena in practical underground power cables. This method is based on the same algorithm as the charge simulation method for electro-static field that is convenient and effective in dealing with composite material and open space. It is successfully applied to the calculation of temperature rise of practical power cables in protection pipes buried in non-uniform soil and then to the evaluation of the allowable current in the cable system.
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Shuichi Sasano, Mengu Cho
2001 Volume 121 Issue 11 Pages
1012-1018
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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In order to study partial discharge phenomenon in a gas insulated system, we have developed a simulation code using the MC-PIC (Monte-Carlo Particle-in-Cell) method. The MC-PIC code can simulate ionization and attachment under non-uniform unsteady electric field with a sufficient quantitative accuracy by considering collision cross-section data as close as possible to the real data. A negative DC corona discharge in SF
6 is simulated. The electric field is distorted near the rod electrode once the corona discharge starts, because the positive ions and negative ions are polarized near the rod electrode after the electron avalanche ends. The electric field strength decreases in comparison with the initial condition due to the negative space charge. The image current due to the motion of electron dominates the current pulse. The simulation result agrees well with the experimental result.
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Yasumasa Takao, Hidehiro Kamiya, Makio Naito, Hideo Okuma
2001 Volume 121 Issue 11 Pages
1019-1024
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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This paper offered a polarization in transparent optical microscopy as one of observing technique for internal-structure (powder packing-structure) of the resin polymer composite system filled with ceramic filler-powder. The technique visualized the heterogeneous powder packing as brightened features at crossed-polarization, and contributed to clarify the influence of particle size distribution and coupling treatment of filler-powder on internal microstructure of the polymer composite. The brightened features were appeared to have an optical anisotropic property; i.e., repeated changes between bright/dark under rotating specimens at every 45° increments, optical addition/subtraction retardations and positive optical character of elongation under observation using tint plate. The optical anisotropy was often observed in the filler systems with narrow size distribution and the systems under coupling treatment. The amounts of optical anisotropy showed the good agreement with rheological properties in systems, although they could not be understood only from filler primary properties; such as median diameters, particle size distributions and specific surface areas.
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Mamoru Takahashi, Hidetoshi Matsuki
2001 Volume 121 Issue 11 Pages
1025-1031
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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For use of implanted apparatus such as an artificial heart, monitoring of driving condition and detection of trouble are necessary. These informations exist in the body and have to be transmitted through the skin. So the transcutaneous signal transmission system without wire penetrating skin is to be considered.
The driving power of the artificial heart is provided from the outside of the body to the inside. One of this method is that a pair of coil is arrraged with the skin in between and this magnetic coupling enables power transmission in contactless condition. In the same way, magnetic coupling method is utilized in signal transmission system and able to transmit the information inside the body to the outside with transcutaneous coil. Signal transmission coil has been designed, allowing for noise disturbing, and reported to have sufficient transmitting ability.
In this report, the multiplexing of the transcutaneous signal transmission system is considered experimentaly. We design the signal transmission coil and decide the signal frequency band based on frequncy characteristics of coil. Moreover 5 channel signal transmissions are practiced in frequency-division multiplex and examined in effect on noise removal and signal separation.
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Fumio Morimoto, Tadao Nozawa, Norimoto Nouchi, Kunio Fujii
2001 Volume 121 Issue 11 Pages
1032-1038
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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The cause of drastic decrease of coercive force in FeCoV and FeNiMo films due to sandwiching by thin FeNiMo layers (about 2% in volume) is studied. The features of magnetization processes of these multi-layer films are investigated by observation of magnetization curves and magnetic domain structures. The drastic reduction in coercive forces seems to be related to anisotropic magnetization of very thin FeNiMo film which was evaporated firstly on the substrate.
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Kazunori Kadowaki, Sakae Nishimoto, Isamu Kitani
2001 Volume 121 Issue 11 Pages
1039-1045
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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Pressure signal and discharge light from tree channel were simultaneously observed when 50kV pulses (50ns in width) were repeatedly applied to an epoxy block with point-plane electrodes. The positions of pressure sources were measured from the propagation time of pressure wave from the source to an AE sensor which was located on the back of the plane electrode. The tree length estimated from the pressure signal was in good agreement with the length estimated from the discharge light. The height of the pressure signal due to the induced charge on the plane electrode tended to increase with increasing the number of the voltage application for both polarities. The pressure signal due to the volume expansion of the tree became larger by the successive voltage application in the negative point, while it became smaller in the positive point. The difference between the polarities could be explained by the effect of the residual charge near the point electrode.
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Koichi Tsuruta, Hiroko Kido, Noriyuki Tanaka, Takeshi Yanagidaira
2001 Volume 121 Issue 11 Pages
1046-1047
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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The ratio of the isotope, and its charge state and energy distribution of zinc ions generated from a low current DC vacuum arc were measured using a mass spectrometer which was equipped with an energy analyzer. It appeared that the generation ratio of the isotope ions was proportional to the ratio of the isotope of the metal zinc electrode. The energy of the singly charged ions has a wide distribution with a peak in the range 10 to 20eV, independent of the isotopes.
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Akio Tanaka, Nobuo Takehira, Toshikatsu Miki
2001 Volume 121 Issue 11 Pages
1048-1049
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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Recently, the use of rhombic coils, parallelogram coils or elliptic coils has been proposed in eddy current sensor or eddy current testing. However, it is generally difficult to analyze the magnetic field produced by these coils. Therefore, there is hardly any report touching the self-inductance which is fundamental character-istics of the coil. In this letter, a single-layer coil has been noticed among the elliptic coils. And the exact calculation formula of the self-iductance has been shown using the same coefficient as Nagaoka's coefficient. In addition, the validity of the calculation formula has been confirmed by comparing measured values with calculated ones.
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[in Japanese]
2001 Volume 121 Issue 11 Pages
1052
Published: November 01, 2001
Released on J-STAGE: July 15, 2008
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