研究者詳細 - 植田　浩史

MISC - 植田　浩史

分割表示 564 件中 381 - 400 件目／全件表示 >>

スラッシュ窒素冷却下における高温超電導線材の過電流通電特性

百足弘史, 瓜生季邦, 佐藤俊祐, WANG Xudong, 植田浩史, 石山敦士, 淵野修一郎, 古瀬充穂, 池内正充, 大野隆介

低温工学・超電導学会講演概要集 80th 2009年

コイル巻線化されたYBCO集合化導体の常電導伝播特性解析

植田浩史, 石山敦士, 式町浩二, 平野直樹, 長屋重夫

低温工学・超電導学会講演概要集 80th 2009年

トロイダル配置されたY系SMESコイルの保護動作

植田浩史, 石山敦士, 式町浩二, 平野直樹, 長屋重夫

低温工学・超電導学会講演概要集 81st 2009年

66kV系統YBCO超電導ケーブルの過電流通電特性解析

WANG Xudong, 植田浩史, 石山敦士, 大屋正義, 湯村洋康, 藤原昇, 塩原融

低温工学・超電導学会講演概要集 80th 2009年

SEMS用冷凍機伝導冷却大電流YBCO超電導コイルの安定性と保護

植田浩史, 石山敦士, 式町浩二, 平野直樹, 長屋重夫

電気学会超電導応用電力機器研究会資料 ASC-09 ( 20-39 ) 1316 - 1319 2009年

球体バルク超電導体を用いたアクティブ磁気浮上の位置制御

菅兼治, 植田浩史, 我妻洸, 石山敦士

電気学会超電導応用電力機器研究会資料 97 ( 16-35.37-38 ) 2008年

Fatigue tests of YBCO coated conductors

S. Bamba, Y. Tanaka, T. Ando, H. Ueda, A. Ishiyama, Y. Yamada, Y. Shiohara

8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) 97 2008年

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

In this paper, we report the fatigue characteristics of IBAD/PLD YBCO coated conductors. A YBCO coated conductor used in the superconducting coil of a SMES system is repeatedly subjected to mechanical tensile or compressive strain due to the Lorentz force during electrical charging or discharging. The superconducting characteristic of this conductor may deteriorate because of this cyclic strain. Therefore, it is necessary to investigate the effect of cyclic strain on the superconducting characteristics of YBCO coated conductors that have a laminated structure. We developed an experimental apparatus with a U-shaped sample holder in order to apply cyclic strain to the sample tape. This apparatus was used to perform the fatigue tests on YBCO coated conductors in liquid nitrogen in the absence of an external magnetic field. The strain cycles with the maximum strain epsilon(max) (zero external strain -> epsilon(max) -> zero external strain) were applied and repeated up to 5000 times, and the I-c measurements were performed at epsilon(max). Therefore, the application of cyclic strain with emax ranging from 0.3% to 0.5% did not result in any significant deterioration of the superconducting characteristics of the conductor.

DOI： 10.1088/1742-6596/97/1/012170

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蛍光剤を用いた2次元温度分布可視化システムによるYBCO超電導線材の常電導転移・伝播の可視化

石山敦士, 土屋元計, 植田浩史, 加藤英幸, 奈良広一, 塩原融

電気学会超電導応用電力機器研究会資料 97 ( 18-34 ) 2008年

Visualization of Normal-zone initiation and Propagation using Fluorescent Paints

A. Ishiyama, H. Murakami, M. Tsuchiya, H. Ueda, H. Kato, K. Nara, Y. Shiohara

8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) 97 12169 2008年

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

To establish a stability criterion for Yttrium barium copper oxide (YBCO)-coated conductors, it is necessary to clarify their transient thermal characteristics. Thermocouple thermometers, resistance thermometers, or the relation between the temperature and resistance of the stabilizer used for the conductors are generally employed for measuring their temperatures. However, these methods can only be employed to observe fixed-point data. Hence, it is difficult to observe the longitudinal and transversal distributions of temperatures in coated conductors. In this study, we adopt a method for the visualization of the temperature distribution of coated conductors by using fluorescent paints whose color changes with temperature. By adopting this method, we can measure the two-dimensional distribution of temperature in magnetic fields and at cryogenic temperatures. Therefore, local heat generation in the YBCO tapes can be observed with a higher spatial resolution and the uniformity in the critical current density of YBCO tapes can be identified. In this paper, we describe the developed thermal visualization system and the preliminary experimental results of the visualization of normal-zone initiation and propagation in YBCO sample strips. Further, we also report a part of the normal-zone initiation and propagation mechanism by electromagnetic field and heat transfer analyses by employing a three-dimensional finite element method (FEM).

DOI： 10.1088/1742-6596/97/1/012169

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Degradation of YBCO Coated Conductors Caused by Over-current Pulses

X. Wang, H. Ueda, A. Ishiyama, Y. Iijima, T. Saitoh, N. Kashima, M. Mori, T. Watanabe, S. Nagaya, T. Katoh, T. Machi, Y. Shiohara

8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) 97 2008年

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

YBCO tapes are expected to be used in future high temperature superconductor (HTS) applications because they have excellent J(c) characteristics at high temperatures and in high magnetic fields. For application to electric power devices such as transmission cables, transformers, and fault current limiters, the YBCO tapes might be subjected to a short-circuit fault current that is 10-30 times the normal operating current. In a worst-case scenario, YBCO tapes may degrade and burn. Therefore, it is important to clarify the mechanism of the degradation caused by an over-current pulse. This paper describes the experimental results of the degradation of the YBCO tapes through a series of over-current pulse tests. We focussed on the degradation temperature and carried out the experiments with different bending strains. Measurements were performed as a function of the amplitude of an over-current pulse for an operating temperature of 80 K (Gifford-McMahon cryocooler was adopted) in a self-field. We also examined a tape after the experiments with magneto-optical (MO) imaging, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electron diffraction patterns.

DOI： 10.1088/1742-6596/97/1/012150

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Degradation of YBCO Coated Conductors Caused by Over-current Pulses

X. Wang, H. Ueda, A. Ishiyama, Y. Iijima, T. Saitoh, N. Kashima, M. Mori, T. Watanabe, S. Nagaya, T. Katoh, T. Machi, Y. Shiohara

8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) 97 12150 2008年

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

DOI： 10.1088/1742-6596/97/1/012150

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CIC導体内におけるNb₃Sn素線の超電導特性の数値解析・評価

村上陽之, 植田浩史, 石山敦士, 小泉徳潔, 奥野清

電気学会超電導応用電力機器研究会資料 18 ( 2 ) 1051 - 1054 2008年

YBCO超電導ケーブル導体の過電流通電特性解析

石山敦士, WANG Xudong, 西尾幸恭, 植田浩史, 八木正史, 向山晋一, 鹿島直二, 長屋重夫, 塩原融

電気学会超電導応用電力機器研究会資料 468 ( 15-20 ) 2041 - 2045 2008年

Fatigue tests of YBCO coated conductors

S. Bamba, Y. Tanaka, T. Ando, H. Ueda, A. Ishiyama, Y. Yamada, Y. Shiohara

8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) 97 12170 2008年

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

DOI： 10.1088/1742-6596/97/1/012170

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単層1m級YBCO超電導ケーブル導体の過電流通電特性-実験および数値解析-

植田浩史, 西尾幸恭, WANG Xudong, 石山敦士, 八木正史, 向山晋一, 鹿島直二, 長屋重夫, 塩原融

電気学会超電導応用電力機器研究会資料 97 ( 45-51 ) 2008年

Overcurrent Characteristics of 1 m Long Superconducting Model Cable using YBCO Coated Conductors

H. Ueda, X. Wang, A. Ishiyama, S. Mukoyama, M. Yagi, N. Kashima, S. Nagaya, Y. Shiohara

8TH EUROPEAN CONFERENCE ON APPLIED SUPERCONDUCTIVITY (EUCAS'07) 97 12168 2008年

記述言語：英語出版者・発行元：IOP PUBLISHING LTD

In applications to power transmission cables, a number of YBCO tapes would be assembled and wound spirally on a Cu former. The YBCO tapes and the Cu former would be connected in parallel and could be subjected to short-circuit fault currents 10 to 30 times the operating current. The fault currents would drive the YBCO tapes into the normal state and thus generate Joule heating for the duration of the fault. Therefore, in order to examine the stability and feasibility of YBCO power transmission cables, it is important to demonstrate the redistribution of the transport current and the electromagnetic coupling between the YBCO tapes and the Cu former during a short-circuit fault current. We constructed a 1 m long superconducting model cable and subjected it to an overcurrent with a peak of 31.5 kA(rms) for a duration of 2.0 s, as established by JEC (Japanese Electrotechnical Committee), in a liquid nitrogen bath. We examined the redistribution of the transport current between the YBCO sample tapes and the Cu former by using Hall probes. In addition, we developed a novel computer code based on the finite element method and an equivalent circuit in order to clarify the characteristics of the redistribution of the transport current and the thermal behaviour within the cable. Finally, we designed a 10 m long cable that would reach the degradation temperature of the YBCO tape due to the fault currents.

DOI： 10.1088/1742-6596/97/1/012168

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医薬用たんぱく質の高勾配磁気分離システムによる高速分離・精製・回収用フィルターの設計

我妻洸, 淵野修一郎, 古瀬充穂, 植田浩史, 石山敦士, 柁川一弘

低温工学・超電導学会講演概要集 78th 2008年