研究者詳細 - 金　錫範

MISC - 金　錫範

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Fast Computation Method of Magnetic Field Homogeneity for NMR/MRI REBCO Pancake Coils

Ryosuke Miyao, Hajime Igarashi, SeokBeom Kim, So Noguchi

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 27 ( 4 ) 610 - 616 2017年6月

記述言語：英語出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

Recently, multiple-stacked pancake coils wound with rare-earth barium copper oxide (REBCO) tapes are expected to apply for nuclear magnetic resonance (NMR)/MRI magnets. Since REBCO tapes are very expensive, REBCO magnets should be optimally designed so as to minimize the winding volume. Surely, a highly homogeneous magnetic field is also required for NMR/MRI magnets. To achieve the accurate homogeneity of REBCO magnets, it is necessary to compute the contribution of all REBCO layers one by one, because currents carry over very thin area compared with a whole magnet cross section. However, NMR/MRI magnets generating high-magnetic field usually consist of multiple-stacked REBCO pancake coils, and each pancake coil has > 300 turns. To evaluate the field homogeneity contributed by every REBCO layer, therefore, it is necessary to repeatedly compute more than ten thousand times as one magnet shape. In a conventional optimization algorithm, it is necessary to iterate more than one million times for the optimal design of an NMR or MRI magnet. Such an iterative computation is not realistic. Based on the backgrounds, we present a fast computation method using the shift operator of spherical harmonics. In addition, to confirm the validity of the proposed method, it was applied to the shape optimization of 1.5-T MRI magnet. In this paper, the optimization result and computation time are also shown.

DOI： 10.1109/TASC.2016.2637937

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液体窒素冷却の小型NMR用高温超伝導バルクマグネットの開発

金錫範

低温工学 52 ( 1 ) 11 - 17 2017年

Development of HTS bulk magnets for compact NMR devices cooled by liquid nitrogen

52 ( 1 ) 11 - 17 2017年

サイクロトロン応用のための高温超電導マグネットの発生磁場精度評価

粟津佑太, 植田浩史, KIM SeokBeom

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

銅メッキ付きマルチフィラメント化REBCO線材の電流分布解析

盛川瑛亮, 小泉智暉, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

高温超電導バルク体による積層構造小型NMR装置用マグネットの試料測定空間拡張に関する基礎研究

乙倉孝輔, 深田進, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

無絶縁高温超電導コイルを想定した高温超電導線材間の電気的接触抵抗の圧力依存性に関する研究

立田貴裕, 大草晴義, 民健太郎, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

鉄リングによる超電導マグネットの磁場補正に関する研究

有岡直紀, 野村亮太, 富坂良和, 植田浩史, KIM SeokBeom

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

マルチフィラメント高温超電導線材で巻線された高温超電導コイルの遮蔽電流解析

植田浩史, 小泉智暉, 盛川瑛亮, KIM SeokBeom

低温工学・超電導学会講演概要集 95th 2017年

三次元超電導アクチュエータの床・壁走行間の高温超電導バルク体移動子の動的特性に関する研究

山崎尊雄, 平塚祐介, 中嶋淳夫, 植田浩史, KIM SeokBeom

低温工学・超電導学会講演概要集 95th 2017年

医療用タンパク質の高勾配磁気分離用磁性フィルターの周囲の磁性粒子の挙動解析

森優輝, 窪田幹久, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

単板磁気試験器を用いた電磁鋼板の磁気特性測定方法に関する研究

藤本賢哉, 中川拓弥, 大原慎也, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

小型NMR装置用のハルバッハ配列永久磁石の磁場均一度向上に関する研究

美濃孝明, 野村亮太, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

連結高温超電導バルク体移動子を用いた三次元アクチュエータの動的特性に関する研究

中嶋淳夫, 平塚祐介, 山崎尊雄, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

小型NMR relaxometry装置用の高温超電導マグネットの形状に関する基礎研究

石井翔己, 菅生圭登, 喜来雅人, KIM SeokBeom, 植田浩史

電気・情報関連学会中国支部連合大会講演論文集(CD-ROM) 68th 2017年

Study of the Dynamic Properties of HTS Bulk Movers for Traveling Along Vertical Walls as a Three-Dimensional Actuator

S. B. Kim, M. Sawae, S. Ozasa

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 26 ( 4 ) 2016年6月

記述言語：英語出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

We have been investigating three-dimensional actuators using bulk high-temperature superconductors (HTS) as transportation devices that move in free space. The large flux-pinning force of HTS allows motion without contact, even when the levitation force is not aligned against gravity, which could make them useful in clean or dangerous environments, such as clean rooms for semiconductor fabrication or in tunnels containing flammable gas. An actuator prototype, consisting of an HTS bulk with trapped magnetic field as a mover and a two-dimensional array of electromagnets as a stator, has been developed. In a previous study, the dynamic characteristics for traveling over floors were examined. In this study, horizontal, vertical, and oblique motions along vertical walls have been investigated. Movement characteristics have been studied for HTS bulks of two diameters and related to measurements of the axial components of their trapped magnetic fields. Maximum vertical displacements of 5.80 and 11.5 mm were achieved for HTS bulks of 60- and 46-mm outer diameters, respectively.

DOI： 10.1109/TASC.2016.2535665

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Study on the Magnetic Field Homogeneity of HTS Bulk Magnets Including the Degraded HTS Bulk for Developing the Compact NMR Relaxometry

S. B. Kim, K. Hojo, D. Miyazawa

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 26 ( 4 ) 2016年6月

記述言語：英語出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

We have been studying the compact magnet for NMR device that consists of a stacked high-temperature superconducting (HTS) GdBCO bulk annuli trapped by a field cooling method. It was difficult to trap the uniform magnetic field above 4.7 T (200-MHz-class NMR magnet) and field homogeneity under 0.01 ppm/cm(3) at liquid nitrogen temperature (77.4 K) because of the low Jc-B characteristics of present HTS bulks. On the other hand, the strength and homogeneity of the magnetic field required for NMR relaxometry device are 1.5 T and 150 ppm/cm(3), respectively. Therefore, we have been investigating the development of the compact magnet for NMR relaxometry device. In our previous work, we obtained the trapped magnetic field over 1.5 T at 77.4 K using the stacked HTS bulk magnet with 80-mm height, and 150-ppm/cm(3) field homogeneity was obtained using the fabricated field compensation methods. However, the asymmetric problem of the magnetic field uniformity occurs by the different superconducting characteristics of HTS bulks when we produce the compact NMR magnet by stacking a large number of HTS bulks. Therefore, in this study, the field homogeneity of HTS bulk magnet by the arrangement of the degraded HTS bulk was investigated using 3-D FEM analysis. We examined the effects of the stacking position of degraded HTS bulk using various Jc-B characteristics.

DOI： 10.1109/TASC.2016.2521381

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Development of Non-Contact Levitated Rotating Machine Using HTS Bulks and Permanent Magnets

S. B. Kim, K. Nakamura

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 26 ( 4 ) 2016年6月

記述言語：英語出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

We have studied a non-contact magnetic levitation system using ring-shaped high-temperature superconducting (HTS) bulks and ring-shaped permanent magnets (PMs). Because the HTS bulks were magnetized by PMs fixed between the HTS bulks, this PMs levitated with strong restoring force. We used a stator coil to rotate the iron shaft combined with PMs. In order to rotate the shaft stable, restoring the force of radial direction is very important. Therefore, the ring-shaped PMs magnetized in the radial direction were fitted to the shaft. In this rotating system, we focused on two parameters, i.e., the rotation and the control. In the rotation, we measured the maximum rotating speed and the axial vibration due to the rotating speed. The three types of stator coils were designed by electromagnetic analysis, and these stators were tested experimentally.

DOI： 10.1109/TASC.2016.2518021

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Dynamic Characteristics of a 3-D Superconducting Actuator With Arranged Permanent Magnets and Electromagnets

S. B. Kim, S. Ozasa, M. Sawae

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 26 ( 4 ) 2016年6月

記述言語：英語出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

High-temperature superconductor (HTS) bulks can trap high magnetic fields due to strong flux pinning. We have been investigating 3-D superconducting actuators using HTS bulks for transportation applications. The actuator consists of an HTS bulk as a mover and 2-D arranged electromagnets (EMs) as a stator. However, many EMs and power supplies would be needed to produce a 3-D actuator with a large moving area; therefore, a new type of 3-D actuator based on a 2-D array of permanent magnets (PMs) in combination with a small number of EMs was designed and tested. In this new type of actuator, the speed control of the HTS bulk mover is very important to develop a reliable noncontact transportation device. In this paper, the dynamic movement characteristics of the HTS bulk mover in the new type of actuator were experimentally investigated as a function of the gap distance between PMs and the drive current patterns.

DOI： 10.1109/TASC.2016.2536440

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Shape Optimization of the Stacked HTS Double Pancake Coils for Compact NMR Relaxometry Operated in Persistent Current Mode

S. B. Kim, R. Saito, M. Takahashi, Y. J. Park, M. H. Lee, Y. K. Oh, S. Noguchi

IEEE TRANSACTIONS ON APPLIED SUPERCONDUCTIVITY 26 ( 4 ) 2016年6月

記述言語：英語出版者・発行元：IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC

The low temperature superconducting (LTS) coils are used in NMR devices, and liquid helium is used for their cooling. It is possible to reduce the operating costs by manufacturing the superconducting magnet that is consisted of the high temperature superconducting (HTS) coil using liquid nitrogen cooling. We have been developing the NMR relaxometry devices using the HTS double pancake coils and operated in the persistent current mode at liquid nitrogen temperature. The required strength and homogeneity of the magnetic field of proposed NMR relaxometry devices are 1.5 T and 150 ppm/cm(3), respectively. To achieve the target field strength of 1.5 T, it is necessary to increase the numbers of pancake coils and winding turns of each coil, and the large operating current is required as much as possible. In this paper, I-c - B properties of HTS wire and superconducting joint are measured to determine the operating current (load line) for the proposed NMR relaxometry devices. Moreover, 3-D finite-element-model-based analysis was carried out to design the stacked HTS magnets for compact NMR relaxometry with downsizing and low cost.

DOI： 10.1109/TASC.2016.2518487

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