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Volume 111, Issue 8
Displaying 1-10 of 10 articles from this issue
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Naoki Koshizuka1991 Volume 111 Issue 8 Pages 693-701
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSDownload PDF (1430K) -
Kenji Ebihara, Toshiyuki Matsumoto, Tomoaki Ikegami, Yasunori Shiraish ...1991 Volume 111 Issue 8 Pages 702-710
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSPulsed Plasmas generated by both a pulsed inductive discharge and a coaxial pulsed discharge were applied to sputter YBa2Cu3O7-x bulk targets and deposit YBaCuO thin films. The characteristics of these plasmas were investigated by using the spectroscopic technique and an image converter camera. Optical emission spectral measurements showed that a variety of neutral and ionic species, including Y, Y+, Ba, Ba+, Cu and Cu+ appear. The time dependence of the emission intensity and the flaming pictures were analyzed to obtain the plasma flow velocity of the order of 106cm/s. The surface morphology of as-grown films deposited on a crystal silicon substrate has partially a granular character. The optimum deposition conditions of these pulsed plasma processes were investigated to prepare the YBaCuO films with the stoichiometric constitution.View full abstractDownload PDF (2411K) -
Yoshio Saito, Akira Nishitsuji, Yuji Matsuura, Takeshi Sakaguchi1991 Volume 111 Issue 8 Pages 711-718
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSThe electron energy distribution (EED) in the positive column of the glow discharge is changed its shape by collision mechanisms between electrons and neutral atoms, for example elastic, excitation and ionization collisions.
We calculated EED corresponding to various combinations of those collision cross sections by using a Boltzmann equation method.
We added the collision terms concerned with metastable atoms to the Boltzmann equation, and investigated the relationship between collision mechanisms and the transformations of EED.
Moreover, we measured EED in the positive column of He glow discharge under the condition of 0.5-2.5Torr, 5-35mA by using the second harmonic method.
This is one of Langmuir probe methods. These measured EED was also compared with calculated one.
As a result, we estimated the validity of the present collision cross sections and the effect of collision mechanisms on the variation of EED.
This study is useful to inspect a collision mechanism and make a plasma model in practical positive column of the glow discharge.View full abstractDownload PDF (1095K) -
Hajime Tsuboi, Tadashi Naito, Akihiro Sakurai1991 Volume 111 Issue 8 Pages 719-726
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSIn this paper, a boundary element method using spatial eigenmodes for electromagnetic field analysis is proposed. Mapping the computation model with rotational symmetries, reflective symmetries or rotational symmetries including reflective symmetries to a group of spatial eigenmodes, the equivalent reduced models are obtained. In the method, the applicability becomes wide because arbitrary external source terms can be chosen. Furthermore, in a model including asymmetry regions, a new method, which can save the merit of the symmetries, is proposed. Finally, the validity of the proposed method is proved by numerical simulations.View full abstractDownload PDF (2484K) -
Tetsuro Shigemizu, Noriyasu Ohno, Hiroshi Fujiyama1991 Volume 111 Issue 8 Pages 727-732
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSThe gaseous breakdown conditions by the microwave field were theoretically and experimentally investigated in the presence of an external crossed magnetic field. We developed the calculating method by taking account of collisions between electrons and neutral gases, and electron losses to a boundary in the magnetic field to be able to calculate the breakdown voltages in a low gas pressure range from 1×10-4 to 1×10-2Torr. These calculated results are in good agreement with experimental ones. In the narrow-gap less than the wavelength of the microwave, both the magnetic field and the electron loss to the boundary play an important role for the breakdown condition. Coaxial-type electron cyclotron resonance (ECR) plasmas can be generated in a metal coaxial tube with a gap length of 4.5mm gap.View full abstractDownload PDF (865K) -
Yasuyuki Tsutsumi, Kun Ono, Kannichi Fujii, Masaru Higaki1991 Volume 111 Issue 8 Pages 733-740
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSVHF and UHF electromagnetic noise from corona discharge and spark discharge at point-toplane electrodes in air are measured and the peculiar patterns of their spectra are reported.
Gap lengths between electrodes are 1 to 11mm and a radius of the needle tip is 0.8mm. Positive and negative switching impulses are used as the testing high voltage.
The spectra of the corona discharge are shown to have following feature compared with that of spark discharge. They have (1) more than 20 dB μV lower noise levels which depend on the applied voltage and the discharge circuit (2) less high frequency components (3) steeper peaks on the spectra and (4) at least some of the steep peaks correspond with resonant conditions of the discharge circuit.
These findings could be applied to location or specification of the discharge source at the insulation test for high voltage apparatus.View full abstractDownload PDF (1510K) -
Takayuki Yamakita, Tomio Ariyasu1991 Volume 111 Issue 8 Pages 741-746
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSThis paper describes the relationship between the superstructure of polymer, blending low density polyethylene (LDPE) and high density polyetylene (HDPE), and tree intiation. We have observed the superstructure (lamella and spherulite) of blended polyethylene using a transmission electron microscope and a polarizing microscope, and investigated relation between blending ratio of LDPE and HDPE and tree initiation voltage. As a result, when HDPE was blended from 5% to 40%, tree initiation voltage raised. In order to find the cause of this rise in voltage, we have continuously observed crystallization of blended polyetylene through a polarizing microscope. When temperature falls from melting point, first at 120°C HDPE spherulites were formed. Then, at 100°C the LDPE spherulites were produced in conjunction with HDPE spherulites. At this time, trans-crystal yielded between both spherulites, and bonded LDPE spherulites and HDPE spherulites. Trans-crystal strongly bonded at spherulite borders which were electrically weak and, raised the tree initiation voltageView full abstractDownload PDF (2897K) -
Yasuhiko Kako, Shigetaka Watanabe, Yutaka Higashimura1991 Volume 111 Issue 8 Pages 747-753
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSNew test method for internal PD resistance of insulating materials have been studied intensively in the Task Force in CIGRE for over ten years. Recently, the Method II which was developed by authors is now under studying as the international round robin test proposed by domestic Task Force.
This paper describes the new test method concretely and shows some typical test results. This test electrode system is characterized by adhesion of test specimen to the embedded sphere electrode and it may be applicable to all sort of insulating material for the internal PD resistance test under uniform partial discharges. The most important point of this method is to realize the complete adhesion by skillful techniques. It was ascertained that the spread of test data may depend only on the uniformity of materials by this method and the excellent life data can be obtained for some specific materials.View full abstractDownload PDF (1443K) -
Hideo Hirose1991 Volume 111 Issue 8 Pages 754-762
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSThe Weibull distribution plays a very important role in the engineering field, especially when we deal with the breakdown voltage or the lifetime of an insulation. This paper derives mainly three conclusions about the parameter and the percentile point estimations in the case we must search for the three Weibull parameters.
(1) When all the three parameters tend to infinite values, we could use the extended maximum likelihood estimate for the percentile point estimator. However, the limiting form of the Weibull distribution transfigures to the double exponential distribution. Thus, it is the proper way in handling the data that they are extracted from the double exponential distribution.
(2) We can judge whether the data are subjected to the Weibull or the double exponential distribution by using the skewness and the number of sample size.
(3) Even if the data are extracted from the Weibull distribution, we can treat them as the data extracted from the double exponential distribution if the shape parameter of the Weibull distribution is large in some extent.View full abstractDownload PDF (1024K) -
Katsutoshi Kudo1991 Volume 111 Issue 8 Pages 763-764
Published: August 20, 1991
Released on J-STAGE: July 15, 2008
JOURNAL FREE ACCESSDownload PDF (610K)
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