Faculty Profiles - KIM Seokbeom

MISC - KIM Seokbeom

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次世代医療用スケルトンサイクロトロンに用いる高温超電導コイルシステムの電磁力解析

粟津佑太, KIM SeokBeom, 植田浩史, 野口聡, 渡部智則, 長屋重夫, 吉田潤, 福田光宏, 石山敦士

低温工学・超電導学会講演概要集 97th 88 2018.11

無絶縁REBCOマグネットのターン間接触抵抗の測定方法

野口聡, 野口聡, 立田貴裕, 植田浩史, KIM Seokbeom, 石山敦士

低温工学・超電導学会講演概要集 97th 98 2018.11

高強度小型多機能スケルトンサイクロトロンの開発―遮蔽電流磁場解析―

粟津佑太, KIM SeokBeom, 植田浩史, 野口聡, 石山敦士, 渡部智則, 長屋重夫, 吉田潤, 鶴留武尚, 高橋伸明, 三上行雄, 福田光宏

低温工学・超電導学会講演概要集 96th 78 2018.5

2G HTS magnet with smart insulation method

Seok-Beom Kim, Young-Sik Jo, Hyung-Wook Kim, Seog-Whan Kim, Doohun Kim, Rock-Kil Ko, Dong-Woo Ha, Heui Joo Park, Ho Min Kim, Dong-Gyun Ahn, Jung-Pyo Hong, Jin Hur

IEEE Transactions on Applied Superconductivity 28 ( 3 ) 547 - 563 2018.4

Language：English Publisher：Institute of Electrical and Electronics Engineers Inc.

This paper proposes an advanced method to satisfy both the stability and charging/discharging time constant requirements of second generation high-temperature superconductor (2G HTS) magnets. This novel method entails installing metal–insulator transition (MIT) material between the turns of the 2G HTS magnets. The MIT material acts as an insulator when the temperature is lower than a certain value. Above this temperature, the MIT material becomes a conductor. This transition can be used as a switch between the turns of the 2G HTS magnets. We refer to this temperature-dependent smart switch as “smart insulation.” Considering the operating temperature, we selected V2 O3 as the material for smart insulation. We have experimentally verified that the advantages of both the insulation magnet (in the superconducting state) and no-insulation magnet (during quenching) can be simultaneously realized.

DOI： 10.1109/TASC.2017.2779491

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Current bypassing and transient stability in a partially insulated HTS coil

SeokBeom Kim, Haruyoshi Okusa, Kentaro Tami, Hiroshi Ueda

IEEE Transactions on Applied Superconductivity 28 ( 3 ) 4603105 - 4603105 2018.4

Language：English Publisher：Institute of Electrical and Electronics Engineers Inc.

The no-insulation (NI) winding technique to improve the transient stability of high-temperature superconducting (HTS) magnets has been studied and a cowinding method using a metallic tape was tested. Normally, the operating current in NI HTS coils is bypassed into the transverse direction due to the normal region generated within the coils. Therefore, a method that controls such current bypassing into the turn-to-turn direction of NI HTS coils was investigated as a means to regulate the effective number of turns. In this study, we experimentally investigated the characteristics of current bypassing in the transverse direction within a test coil wound with a GdBCO tape. First, to find an optimized heater location, a 20-turn HTS pancake with two partial insulation shapes was prepared and tested experimentally. The current bypassing characteristics in the normal region created by heaters (strain gauges) were studied while varying the number of heaters, heater positions, and the amount of heating at liquid nitrogen temperature. Using both short and long heating periods, we found that we could effectively control the number of turns (coil inductance) via long-duration heating.

DOI： 10.1109/TASC.2017.2787108

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Development of HTS Bulk NMR Relaxometry with Ring-Shaped Iron

Seokbeom Kim, Susumu Fukada, Ryota Nomura, Hiroshi Ueda

IEEE Transactions on Applied Superconductivity 28 ( 3 ) 4301505 - 4301505 2018.4

Language：English Publisher：Institute of Electrical and Electronics Engineers Inc.

The compact NMR magnets consisted of the stacked higherature superconducting (HTS) GdBCO bulk annuli trapped by field cooling (FC) method have been developed. The target values of strength and homogeneity of magnetic field for proposed NMR relaxometry are 1.5 T and 150 ppm/cm3, respectively, at liquid nitrogen temperature. Since last year, we have been developing a hardware and software to detect the NMR signals by ourselves. Therefore, we needed to determine the final structure of HTS bulk magnet to be used in the NMR relaxometry. We can obtain the trapped magnetic field over 1.5 T at 77.4 K experimentally. However, it is still difficult to obtain the magnetic field homogeneity under 150 ppm/cm3 experimentally, due to their different superconducting properties. Therefore, in this study, four types of HTS bulk magnets to determine the final structure of compact NMR relaxometry were designed and their field properties including the degraded HTS bulk were investigated using three-dimensional finite-element method analysis. The field properties of 10-stacked HTS bulk magnets with the ring-shaped irons for field compensation and the degraded HTS bulk were investigated experimentally.

DOI： 10.1109/TASC.2017.2785260

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2G HTS Magnet With Smart Insulation Method Reviewed

Young-Sik Jo, Hyung-Wook Kim, Seog-Whan Kim, Doohun Kim, Rock-Kil Ko, Dong-Woo Ha, Heui Joo Park, Ho Min Kim, Dong-Gyun Ahn, Jung-Pyo Hong, Jin Hur, Seok-Beom Kim

IEEE Transactions on Applied Superconductivity 28 ( 3 ) 1 - 4 2018.4

Language：English Publisher：Institute of Electrical and Electronics Engineers (IEEE)

DOI： 10.1109/tasc.2017.2779491

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An Extended Thin Approximation Method to Simulate Screening Current Induced in REBCO Coils Reviewed

So Noguchi, Seungyong Hahn, Hiroshi Ueda, SeokBeom Kim, Atsushi Ishiyama

IEEE Transactions on Magnetics 54 ( 3 ) 1 - 4 2018.3

Language：English Publisher：Institute of Electrical and Electronics Engineers (IEEE)

Superconducting magnets wound with second-generation high-temperature superconductors, i.e., REBa2Cu3O7-x (REBCO, RE = Rare Earth) tapes, are desired to apply high magnetic field nuclear magnetic resonance, MRI, and accelerators. However, a major problem for practical application is an undesirable irregular magnetic field caused by screening currents induced in REBCO tapes. To investigate the screening current-induced magnetic field, a few simulation methods have been proposed. One of the effective simulation methods employs a finite-element method with a thin approximation method. Although the thin approximation method was developed to simulate eddy currents in magnetic steel sheets, and it is not applicable to REBCO tapes carrying a transport current. Therefore, the thin approximation method is extended to simulate screening currents in REBCO tapes considering a carrying transport current. To show the validity of the proposed extended thin approximation method, the screening currents of an REBCO magnet are computed, and the results are compared with the measurement and simulation results of the conventional thin approximation method. The more accurate solution is available by using the proposed methods.

DOI： 10.1109/tmag.2017.2752083

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高温超電導コイルの巻線内電磁力解析

植田浩史, 徳永佳祐, 盛川瑛亮, 小泉智暉, KIM SeokBeom

低温工学・超電導学会講演概要集 97th 2018

単板磁気試験器を用いた電磁鋼板の2Hコイル法による磁界強度測定法の検討

太田葵, 藤本賢哉, 大原慎也, 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) 69th 2018

REBCOコイルの遮蔽電流に起因する巻線内電磁力解析

徳永佳祐, 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) 69th 2018

500MHz LTS/REBCO NMRにおける遮蔽電流磁場解析による磁場均一度評価

盛川瑛亮, 徳永佳祐, 小泉智暉, KIM SeokBeom, 植田浩史, 柳澤吉紀

低温工学・超電導学会講演概要集 97th 2018

高温超電導コイルの小型化とインダクタンス制御に関する研究

西川大亮, 立田貴裕, 大草晴義, 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) 69th 2018

500MHz LTS/REBCO NMRの遮蔽電流磁場解析

盛川瑛亮, 小泉智暉, KIM SeokBeom, 植田浩史, 濱田衞, 柳澤吉紀, 前田秀明

低温工学・超電導学会講演概要集 96th 2018

医薬用タンパク質の高勾配磁気分離用磁性フィルターの断面形状設計

安部拓郎, 窪田幹久, 森優輝, 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) 69th 2018

Numerical Simulation on coupling current in HTS coil wound with multifilamentary HTS tape

植田浩史, 小泉智暉, 盛川瑛亮, KIM SeokBeom

電気学会研究会資料 ( MC-18-001-023/ASC-18-001-023 ) 2018

Study on the Rotation Properties and the Design Issue of Non-Contact Rotating System Using HTS Bulks and Permanent Magnets

R. Okamura, S. B. Kim, Y. Ozaki, H. Ueda

Journal of Physics: Conference Series 871 ( 1 ) 702 - 709 2017.7

Language：English Publisher：Institute of Physics Publishing

In previous study, non-contact rotating system consisting of the ring-shaped high temperature superconducting (HTS) bulks, ring-shaped permanent magnets (PMs) and stator coil was proposed. In this system, HTS bulks were magnetized by PMs and PMs were levitated with strong restoring force. In our previous study, we have constructed the rotating system with the ring-shaped HTS bulks with ID 20 mm, OD 60 mm, and 15-mm thickness. However, since these bulks costs too much, we switched to use HTS bulks with ID 20 mm, OD 60 mm, and 5-mm-thickness to miniaturize the system. However, this system have potential to fail the radial stability of rotating shaft. Therefore, we focused on the rotating and the radial restoring force in terms of the stability of the rotating shaft in the rotating system with 5-mm thickness HTS bulks.

DOI： 10.1088/1742-6596/871/1/012096

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Fundamental study on the magnetic field control method using multiple HTS coils for Magnetic Drug Delivery System

R. Hirano, S. B. Kim, T. Nakagawa, Y. Tomisaka, H. Ueda

Journal of Physics: Conference Series 871 ( 1 ) 969 - 976 2017.7

Language：English Publisher：Institute of Physics Publishing

The magnetic drug delivery system (MDDS) is a key technology to reduce the side effects in the medical applications, and the magnetic force control is very important issue in MDDS. In this application, the strength of magnetic field and gradient required to MDDS devices are 54 mT and 5.5 T/m, respectively. We proposed the new magnetic force control system that consists of the multiple racetrack HTS magnets. We can control the magnetic field gradient along the longitudinal direction by the arrangement of the multiple racetrack HTS magnets and operating current of each magnet. When the racetrack HTS magnets were used, the critical current was reduced by the self-magnetic field. Therefore, the shape design of HTS magnet to reduce the magnet field into the surface of HTS tapes was required. Therefore, the electromagnetic analysis based on finite element method (FEM) was carried out to design and optimize the shape of multiple racetrack HTS magnet. We were able to suppress the reduction of critical current by placing the magnetic substance at upper and lower side of the HTS magnets. It was confirmed that obtained maximum values of magnetic field strength and field gradient were 33 mT and 0.18 T/m, respectively.

DOI： 10.1088/1742-6596/871/1/012104

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Numerical study to obtain the improved field homogeneity of HTS bulk magnet with enlarged inner diameter for compact NMR

S. Fukada, S. B. Kim, T. Nakagawa, R. Nomura, H. Ueda

Journal of Physics: Conference Series 871 ( 1 ) 1488 - 1495 2017.7

Language：English Publisher：Institute of Physics Publishing

The strength and homogeneity of the magnetic field required for NMR relaxometry device are 1.5 T and 150 ppm/cm3 respectively. It is relatively easy to generate the trapped magnetic field over 1.5 T at 77.4 K using the stacked HTS bulks, and 150 ppm/cm3 field homogeneity was obtained using the fabricated field compensation methods on HTS bulks magnet with 20 mm inner diameter. However, it is still hard to obtain 150 ppm/cm3 field homogeneity without field compensation methods. In this paper, in order to improve the trapped magnetic field homogeneity, the HTS bulk magnet with enlarged inner diameter was proposed and studied as the functions of size and shape of HTS bulk. The analytical study based on FEM was carried out to optimize the shape of HTS bulk magnet with enlarged inner diameter.

DOI： 10.1088/1742-6596/871/1/012088

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Improvement in Stability and Operating Characteristics of HTS Coil Using MIT Material Reviewed

Hyung-Wook Kim, Jin Hur, Seog-Whan Kim, Seok-Beom Kim, Rock-Kil Ko, Dong-Woo Ha, Ho Min Kim, Jin-Hong Joo, Young-Sik Jo

IEEE Transactions on Applied Superconductivity 27 ( 4 ) 1 - 4 2017.6

Language：English Publisher：Institute of Electrical and Electronics Engineers (IEEE)

This paper proposes a new method of achieving electrical stability and controllability of a high-temperature superconductor (HTS) coil. The proposed method applied a material with a metal-insulator transition (MIT) property to the turn-to-turn resistance of an HTS coil. As a result, the turn-to-turn resistance remained at the insulator level in the normal state, thus removing delay during charging and discharging. During transient state, the turn-to-turn resistance dropped to the metal level, and current bypass occurs similar to that in a noinsulation coil, thus preventing the coil from burning out. The validity of the MIT characteristic and the proposed method were verified through experiments.

DOI： 10.1109/tasc.2017.2655262

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