巻号一覧
前身誌
122 巻, 11 号
選択された号の論文の9件中1～9を表示しています
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解説
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熊倉 浩明原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 939-942
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーDevelopment of MgB2 tapes prepared by a powder-in-tube method was reported. MgB2 tapes and wires were fabricated with MgB2 powder and several sheath materials such as Cu, Cu-Ni, carbon steel(Fe-C) and stainless steel. High-density MgB2 cores were obtained for these sheath materials. Jc of the as-cold rolled(un-sintered) tape significantly increased with increasing the cross sectional area reduction by the cold working. Hard sheath materials (Fe-C and stainless steel) are effective to enhance Jc values. These results can be explained by the densification of MgB2 core. Un-sintered MgB2/(stainless steel) tapes showed extrapolated Jc values of ∼300-450kA/cm2 at 4.2K and zero field. Sintering after the cold rolling is effective to enhance Jc values. An order of magnitude higher Jc values were obtained for Fe-C and stainless steel sheathed tapes after the sintering. 10m-long MgB2 tapes were fabricated with Ni sheaths. Ic over 200A was obtained for 10m-long un-sintered MgB2/Ni tape. We fabricated small coil with this tape without any sintering. The coil generated 1.3kGauss at 4.2K.抄録全体を表示PDF形式でダウンロード (718K)
論文
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伊藤 晶彦, 橋本 修, 中島 英実原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 943-950
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーIn this study, a resistive-type wave absorber at two frequencies in X and Ku bands using a frequency selective surface (FSS) is examined. First, basic characteristics of the FSS for one frequency and two frequencies are examined theoretically and experimentally. Second, two types of wave absorbers using the FSS are proposed, which are fabricated by two absorption films and two FSS films, respectivery. As a result, good absorption and shielding characteristics of the present wave absorbers are realized for practical use. Moreover the design of the two absorption film type wave absorber can be performed by point matching method. As to the design of the FSS type wave absorber, we also confirm that the design of the conventional single-layer wave absorber can be utilized.抄録全体を表示PDF形式でダウンロード (1276K) -
上野 秀樹, 中山 博史原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 951-957
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーCreeping flashover voltage-time characteristics for the composite insulating configuration by insertion of a barrier between a needle electrode and a plane electrode in N2 gas have been investigated. The maximum on the creeping flashover voltage at around 10μs has been found in N2 gas for the negative polarity. This anomalous voltage-time characteristics will be associated with low field relaxation effect by the accumulated charges on the barrier for the applied pulse voltage with a highly steep wavefront.抄録全体を表示PDF形式でダウンロード (1335K) -
福地 哲生, 山口 幸宏, 名雪 琢弥, 根本 孝七, 内野 喜一郎原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 958-964
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーA laser wavefront sensor of the Shack-Hartmann type capable of simultaneous measurement at two wavelengths was constructed. The sensor uses a single optical path, and is suited for applications such as high voltage discharges in air, in which large insulation distances are necessary. The sensor was used to detect optical path differences due to an impulse discharge in air across a needle-plane electrode gap of gap length 17 mm. Optical path differences were measured at laser wavelengths 532 nm and 1064 nm at 1.6 μs after insulation breakdown across the gap. From the difference in optical path differences at the two wavelengths, a line-integrated electron density distribution in the direction perpendicular to the gap was obtained near the high voltage electrode. The distribution had a peak value of 1.4×1020 m-2 and a full width at half maximum of 4.4 mm. Because of the coverage of a large observation area including the entire gap, the spatial resolution was 1.4 mm, which was inadequate to obtain the precise form of the electron density distribution. However, the results show the possibility of applying laser wavefront sensing to electron density measurement.抄録全体を表示PDF形式でダウンロード (1385K) -
浦江 英孝, 山形 幸彦, 村岡 克紀, 山田 健一郎, 山内 恒, 岡野 浩志原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 965-976
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーA new scheme of removing volatile organic compounds(VOCs) at low concentration, using a combination of densification by a zeolite adsorption with a barrier discharge, has been tested and demonstrated to be effective. VOCs were first adsorbed in a honeycomb-shaped sheet containing zeolites as an adsorbing agent, and then desorbed and destroyed using a barrier discharge between electrodes, which were separated by the honeycomb-shaped sheet and dielectric barriers. After a proof-of-principle experiment to demonstrate the principle of the scheme, four different types of tests were conducted to quantitatively assess its usefulness. An extrapolation to a real size system was made from the obtained experimental results.抄録全体を表示PDF形式でダウンロード (2498K) -
稲熊 剛幸, 津田 紀生, 山田 諄原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 977-982
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーA thermionic energy converter is one of the direct electricity generations. The space charge effect, which limits the thermal emission, is relaxed by enclosing cesium in the converter. In generally, the converter is operated at high emitter temperature because of producing cesium ion by contact thermal ionization. The high operating temperature causes a short emitter’s life that becomes problem for the practical use. The converter is irradiated with the resonance light so that cesium ion is produced by photo-ionization. It is seen that the output by the resonance light irradiation is much larger than that by the visible. A lot of cesium ions can be produced in the space between the electrodes since the most resonance light is absorbed by cesium atom. The maximum value of the short circuit current density is about 1kA/m2. It is found that the resonance light irradiation is one of the effective methods for the practical application.抄録全体を表示PDF形式でダウンロード (824K) -
Choong-Sik Kim, Teruyoshi Mizutani原稿種別: Others
専門分野: Others
2002 年 122 巻 11 号 p. 983-986
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーA PD pulse shape gives us significant information about degradation and PD mechanism. The kurtosis(Ku) and skewness(Sk) that describe the characteristics of a pulse waveform are useful to investigate ageing stages. In this paper, a new plot that we call the Ku-Sk plot is introduced to represent PD properties changing with ageing. According to ageing, PDs tend to concentrate on the third quadrant in the Ku-Sk plot, which represents a flat and left-peaked triangular shape. Moreover, The transition to the third quadrant is accelerated by the oxidation of void surface.抄録全体を表示PDF形式でダウンロード (1012K) -
池田 雅昭, 山本 良美, 川端 秀雄原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 987-995
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーWe succeeded in developing a new type low-density-polyethylene for a power cable insulator. The new type polyethylene has about one hundred times higher volume resistivity than a conventional low-density-polyethylene in the electric field range between 3.5 kV/mm and 77 kV/mm. The space charge accumulation in the new polyethylene is smaller than that in a conventional one. At 150 kV/mm, we observe small amount of space charges near both electrodes in it, even though packet shaped space charges are generated and propagated in a conventional one. The new type polyethylene has about 2×10-6 mol/g carbonyl groups in the bulk. We consider that carbonyl groups may act as trap site and reduce the conduction current and the injection current from electrodes. Moreover, the new type polyethylene shows good water treeing resistance characteristics. In this paper, we descried the developing process and electrical properties of the new polyethylene.抄録全体を表示PDF形式でダウンロード (1703K)
研究開発レター
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福間 眞澄, 光本 真一, 穂積 直裕, 長尾 雅行, 小崎 正光, 河野 唯通, 福永 香, 前野 恭原稿種別: その他
専門分野: その他
2002 年 122 巻 11 号 p. 996-997
発行日: 2002年
公開日: 2003/03/28
ジャーナル フリーIn order to investigate the transient space charge formation in the dielectric materials, short interval space charge measurement systems were developed. The interval of space charge measurement was limited by frequency characteristics of excitation pulse generator and recording digitizing oscilloscope. In this report, we developed shorter interval space charge measurement system using recently available low cost long memory digitizing oscilloscope and high speed switching semiconductors. With this system, the change of space charge distributions in every 10μs interval were measured in a 100μm thick low density polyethylene(LDPE) film.抄録全体を表示PDF形式でダウンロード (535K)
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