Event date： 2023.11 - 2023.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Wellington Convention and Exhibiton Centre, Wellington, NZ  

Event date： 2023.10 - 2023.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Shanghai Jiading Hotel, China   Country：China  

Event date： 2023.10 - 2023.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Shanghai Jiading Hotel, China   Country：China  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Grand Théâtre de Provence, Aix-en-Provence, France   Country：France  

Event date： 2023.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Grand Théâtre de Provence, Aix-en-Provence, France   Country：France  

Event date： 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：西新プラザ   Country：Japan  

Event date： 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：西新プラザ   Country：Japan  

Event date： 2023.5 - 2023.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：タワーホール船堀   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：上智大学四谷キャンパス＋オンライン   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：上智大学四谷キャンパス＋オンライン   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：上智大学四谷キャンパス＋オンライン   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋大学東山キャンパス   Country：Japan  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋大学東山キャンパス   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：長良川国際会議場+WEB   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：長良川国際会議場+WEB   Country：Japan  

Event date： 2022.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：長良川国際会議場+WEB   Country：Japan  

Event date： 2022.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Gold Coast Convention and Exhibition Centre (Hybrid), Australia   Country：Australia  

Event date： 2022.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Gold Coast Convention and Exhibition Centre (Hybrid), Australia   Country：Australia  

Event date： 2022.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Oita University (Dannoharu Campus)   Country：Japan  

Event date： 2022.11

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Online   Country：Japan  

Event date： 2022.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Hawaii Convention Center, Hawaii, USA   Country：United States  

Event date： 2022.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Hawaii Convention Center, Hawaii, USA   Country：United States  

Event date： 2022.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Hawaii Convention Center, Hawaii, USA  

Event date： 2022.10

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Indian Institute of Technology Kharagpur, India   Country：India  

Event date： 2022.10

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Indian Institute of Technology Kharagpur, India   Country：India  

Recent progress of high-temperature superconducting (HTS) wire is significant and commercially available 100’s-meters-class wires show superior homogeneity according to the standard characterization methods such as Hall probe array (TapeStarTM) measurements and/or reel-to-reel four probe measurements. However, the yield of coiling is still not high enough for practical applications especially in large scale HTS based magnets and the mechanism of the failure in the coil winding is not yet clarified. In this study, we have developed characterization techniques to visualize localized current blocking obstacles in long length HTS wires based on magnetic microscopy in conjunction with deep-learning based image analysis. This allows us to detect local obstacles in practical HTS wires and collect information on statistics including obstacle size distribution which were hardly possible to be obtained by the conventional local critical current criterion. In-field current transport properties have also been successfully measured in-situ operand conditions at extremely low electric-field range down to 10-12 V/m, which is inevitable as a base for superconducting magnets in NMR or MRI application. Obtained properties show good agreement with our theoretical model. Local degradation in pancake coil windings has also been visualized. This makes it possible to clarify the degradation mechanisms of the coil windings. Those insights based on the advanced characterization techniques are essential to improve practical HTS wire performances and the reliability of coiling the wires.

Acknowledgements: This work was supported by JSPS KAKENHI Grant Number JP19H05617.

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学 川内北キャンパス＋オンライン   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学 川内北キャンパス＋オンライン   Country：Japan  

Event date： 2022.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学 川内北キャンパス＋オンライン   Country：Japan  

Event date： 2022.7

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Karlsruhe Institute of Technology   Country：Germany  

In this study, bending properties of REBCO tapes and their joints have been investigated by a novel continuous bending property test method of small diameter, and we have succeeded in realizing excellent flexible joining to retain the initial Ic of 95 % or more at the minimum bending diameter of 6 mm. REBCO wire is much superior to BSCCO wire on bending property because of the thin film deposited on the thin substrate. However, the bending test of small diameter has not been sufficiently investigated due to the restriction of the size of the jig, etc. In this study, we proposed a novel bending test method in which REBCO tapes were bent in a loop. Based on image analysis of the loops, we found that the shape of the loop can be described by the clothoid curve in which the curvature linearly changes along the trajectory. This allows us to control the loop diameter by the sample length. Experimental results showed good agreement with that of theoretical analysis. Applying this bending test method, we examined bending characteristics of REBCO tape and bonded samples. While the critical bending diameter was 12 mm in the REBCO tape strand, the bonded samples showed excellent flexibility which surpassed the characteristics of the strand as the position of superconducting layer approaches closer to the neutral line in the bonded sample. We have achieved 6 mm in diameter as the minimum value in the joint.

Acknowledgements: This work was supported by JSPS KAKENHI Grant Number JP19H05617.

Event date： 2022.7

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Karlsruhe Institute of Technology   Country：Germany  

In this study, bending properties of REBCO tapes and their joints have been investigated by a novel continuous bending property test method of small diameter, and we have succeeded in realizing excellent flexible joining to retain the initial Ic of 95 % or more at the minimum bending diameter of 6 mm. REBCO wire is much superior to BSCCO wire on bending property because of the thin film deposited on the thin substrate. However, the bending test of small diameter has not been sufficiently investigated due to the restriction of the size of the jig, etc. In this study, we proposed a novel bending test method in which REBCO tapes were bent in a loop. Based on image analysis of the loops, we found that the shape of the loop can be described by the clothoid curve in which the curvature linearly changes along the trajectory. This allows us to control the loop diameter by the sample length. Experimental results showed good agreement with that of theoretical analysis. Applying this bending test method, we examined bending characteristics of REBCO tape and bonded samples. While the critical bending diameter was 12 mm in the REBCO tape strand, the bonded samples showed excellent flexibility which surpassed the characteristics of the strand as the position of superconducting layer approaches closer to the neutral line in the bonded sample. We have achieved 6 mm in diameter as the minimum value in the joint.

Acknowledgements: This work was supported by JSPS KAKENHI Grant Number JP19H05617.

Event date： 2022.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：早稲田大学西早稲田（理工）キャンパス   Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：青山学院大学相模原キャンパス＋WEB   Country：Japan  

Event date： 2022.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：青山学院大学相模原キャンパス＋WEB   Country：Japan  

Event date： 2021.11

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Online   Country：Japan  

Event date： 2021.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka Convention Center   Country：Japan  

Event date： 2021.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka Convention Center   Country：Japan  

Event date： 2021.10

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Online   Country：Other  

Event date： 2021.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Virtual Conference   Country：Other  

Event date： 2021.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都大学吉田キャンパス+WEB   Country：Japan  

Event date： 2020.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都大学吉田キャンパス+WEB   Country：Japan  

Event date： 2020.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：Japan  

Event date： 2020.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Online   Country：Japan  

Event date： 2020.11

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：オンライン   Country：Japan  

Event date： 2020.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2020.7

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Event date： 2020.1

Language：English   Presentation type：Oral presentation (general)  

Venue：Okinawa Convention Center   Country：Japan  

Event date： 2019.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Miyako Messe Kyoto, Japan   Country：Japan  

Event date： 2019.12

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：京都勧業館みやこめっせ   Country：Japan  

Event date： 2019.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：横浜情報文化センター   Country：Japan  

Research on superconducting materials in MRS-Japan has been promoting broad aspects research from the search for new materials exhibiting higher critical temperature, Tc, to the development of high-performance practical materials and processing technologies, such as wire and bulk materials, joints, high-performance thin films and junctions, as fundamental technologies for highly efficient energy applications as well as electronic applications for sensing and quantum computing. During the last decades, the discovery of different new systems confirmed higher Tc. High critical current density, Jc, is achieved by effective pinning of the quantized vortices formed in the superconductor in magnetic fields. For this reason, researches on nanocomposite superconductors incorporating nanoscale artificial crystal defects have been conducted, and significant performance improvements have been achieved. Advanced material evaluation technology, direct observation of vortices and TDGL simulation technology are also in progress. Practical level of Jc at 20 K is now obtained for MgB2 wires. An iron-based superconductor, (Ba,K)Fe2As2 (Ba-122) are potentially useful for high field applications due to their high upper critical fields of over 50 T and small anisotropy. Jc values of Ba-122 is now reaching to the practical level, leading to high field magnet applications. Developments of long length high-Tc superconducting (HTS) tapes and HTS bulks with high critical current properties have opened new application fields, such as superconducting cables cooled by liquid nitrogen, very high field and/or cryogen-free magnet systems. Recently established superconducting joint technologies connecting HTS tapes will promote developments of magnets equipped with persistent current circuits for NMR and MRI systems. For electronic applications, many Josephson junctions have been researched using HTS and LTS materials. Ramp-edge junction consisting of YBCO and Nb/Al-AlOx/Nb junctions are typical ones. Various applications are developing by the devices, such as mineral resource exploration and microwave filter by the HTS devices and quantum computer and material analysis by the LTS ones. This presentation attempts to review the progress of the research on superconducting materials and to discuss future developments in the superconducting technology.

Event date： 2019.11

Language：English   Presentation type：Oral presentation (general)  

Venue：熊本大学工学部   Country：Japan  

Event date： 2019.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Portage hotel, Marlborough sounds, South Island, New Zealand  

Event date： 2019.10 - 2019.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Fujian Normal University, Fuzhou, China   Country：China  

Event date： 2019.10

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡工大セミナーハウス, 大分県由布市   Country：Japan  

Event date： 2019.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Hyatt Regency Hotel in Downtown Vancouver, Vancouver, Canada   Country：Canada  

Event date： 2019.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Hyatt Regency Hotel in Downtown Vancouver, Vancouver, Canada   Country：Canada  

Event date： 2019.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Connecticut Convention Center, CT, USA  

In our previous study, we demonstrated that the reel-to-reel scanning Hall probe microscopy (RTR-SHPM) has a good advantage on the measurements of spatially resolved in-plane Jc distribution in a long length HTS tapes with a high spatial resolution along the tape width as well as the longitudinal direction. This is inevitable for a detection of localized defect in the tape, evaluation of an effective tape width, measurement of a very narrow tape and/or multi-filamentary tapes. However, one drawback of this method is its relatively low measurement speed around several tens meter per hour or less. In this study, we have succeeded in increasing the measurement speed significantly by introducing a multi-channel Hall probe array. Namely, we can increase the measurement speed N times faster by using a N-channel sensor array without loosing the spatial resolution. We demonstrated a measurement speed of 108 m/h with a longitudinal spatial resolution of 1 mm by using a 3-channel Hall probe array. From the comparison between the previous single channel measurement and the 3-channel measurement, we confirmed that the multi-channel measurement allows us to obtain the same quality Jc mapping with 3 times faster measurement speed. We can increase the measurement speed further just by increasing the numbers of the channels. Therefore, we believe that this method can be a practical diagnostics for a long length HTS tapes even in an industrial scale.
This work was supported by JSPS KAKENHI Grant Number 16H02334 and the New Energy and Industrial Technology Development Organization (NEDO).

Event date： 2019.6

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Wuhan Lotus Pond Grand Hotel, Wuhan   Country：China  

This lecture outlines the state of development of advanced superconducting materials, which is promoted in Japan by national projects, mainly from the viewpoint of the electromagnetic characterization developed by the authors, and also describes the energy application based on these materials. Superconducting materials that are currently being vigorously developed in Japan can be summarized on 1) RE-123 coated conductor, 2) Bi-2223 multi-filamentary tape, and 3) MgB2 multi-filamentary round wire. In addition to the wire developments, a new project on joining technology, which is also important as a basic technology for superconducting applications, has been launched. The application of these advanced superconducting materials is expected to realize a liquid helium-free magnet system, a superconducting liquid hydrogen hybrid energy system utilizing cryogenic heat of liquid hydrogen, and a railway electric cable system by liquid nitrogen cooling. In addition, the development of an ultra-high magnetic field NMR system exceeding 1 GHz has been promoted including the persistent current mode operation. In this lecture, novel characterization techniques and the methodology will be described for resolving key performance issues of these advanced superconducting wires which the authors have worked on. The future prospect of the energy applications based on these materials and requirement for the technological development for the next stage will also be discussed.

Acknowledgements: This study is supported partly by “JSPS KAKENHI (16H02334)”, by the New Energy and Industrial Technology Development Organization (NEDO) and by JST-Mirai Program Grant Number JPMJMI17A2, Japan.

Event date： 2019.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：ノバホール、つくばイノベーションプラザ   Country：Japan  

Event date： 2019.2

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Changwon National University, Changwon   Country：Korea, Republic of  

Event date： 2018.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Tsukuba Internatinal Congress Center   Country：Japan  

Spatial homogeneity of critical current, Ic, in a long coated conductor (CC) is one of the most important requirements for practical applications of CC based devices. However, not only fundamental issues such as the origin of the spatial Ic variation and the influence of fabrication processes, but also a measurement method for the longitudinal Ic variation in the long CCs is not yet established as a standard method. In this study, we have carried out spatially resolved Ic measurements of long CCs by use of reel-to-reel magnetization measurements at 77 K self-field and also at 65 K in subcooled LN2 with applying external magnetic fields up to 2 T. Superconducting layers of the samples were deposited by 1) PLD method on an IBAD-MgO template, and 2) coevapolation method on an ISD-MgO template, respectively. In the former case, artificial pinning centers (APC) were also introduced using BaHfO3. It has been shown that behavior of the spatial Ic variation under external magnetic fields are similar even though the microstructures of the CCs are quite different from each other. Namely, positional dependence of the Ic is collapsed on a single curve if it is normalize by the average value of Ic at each magnetic field condition. This indicates that the spatial variation is almost independent from that of magnetic field dependence. This behavior is similar even in the case of APC doped CC in the IBAD-PLD process. This strongly suggests that the spatial Ic variation comes from macroscopic defects and not from the fluctuation of flux pinning behavior controlled by nano-scale defects. This was also confirmed from very similar APC nano-structures obtained by site-specified TEM observations at high- and low- Ic positions, respectively. Lastly, we considered the influence of spatial resolution and electric-field criterion on the Ic measurements in long CCs by typical two methods, i.e., magnetization measurement and transport measurement from the view point of standardization. Relationship between these two measurements has been discussed quantitatively.

Event date： 2018.12

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：産業総合技術研究所 つくば中央第一事業所   Country：Japan  

Event date： 2018.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Fukuoka University, Fukuoka   Country：Japan  

Event date： 2018.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学金属材料研究所   Country：Japan  

Event date： 2018.11

Language：Japanese   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：福岡県立伝習館高等学学校   Country：Japan  

Event date： 2018.10 - 2018.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Washington State Convention Center, WA   Country：United States  

Event date： 2018.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Schloss Wilhelminenberg, Vieena   Country：Austria  

Spatial homogeneity of critical currents in coated conductors (CCs) is one of the most important issues for practical applications because the minimum Ic in a long length CC will limit the total performance of the tape. This becomes crucial especially in narrower and/or multi-filamentary tapes. In this study, we have investigated current transport properties in face-to-face double stacked (FFDS) CCs by measurements and analysis. Starting from a multi-scale modeling of nonlinear current transport properties in a long length CC strand, we developed a method to analyze detailed properties in the FFDS architecture including contact resistance, local electric field distribution and current sharing among the tapes. It has been shown that the total dissipation, i.e., joint resistance depends on Ic variation and its spatial frequency of the CCs. Based on the measurements on local Ic variation in a 1-mm-wide CC by the reel-to-reel scanning Hall probe microscopy, we analyzed the global current-voltage characteristics of the FFDS CCs at various conditions of joining resistance. Critical current density can be increased by a factor of two effectively and the local electric field concentration can be suppressed one order smaller than that of single strand even though at the same end-to-end voltage criterion of 1 uV/cm. From these analyses, we can lead the conclusion that the FFDS architecture is very effective to suppress the influence of local Ic drop and can improve the robustness and reliability of the CCs.

Acknowledgements: This work was supported by “JSPS KAKENHI (16H02334)” and partly by JST-Mirai Program Grant Number JPMJMI17A2, Japan.

Event date： 2018.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Chinese Academy of Sciences (CAS) Guest House, Beijing, China   Country：China  

Event date： 2018.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Xing Guo Hotel, Shanghai   Country：China  

Event date： 2018.5

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：タワーホール船堀   Country：Japan  

Event date： 2018.5

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Shanghai Superconductor Technology Co., Ltd (SSTC), Shanghai, China   Country：China  

Event date： 2018.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Phoenix   Country：United States  

Combining X-ray tomography and in-field scanning Hall probe microscopy (SHPM), we have succeeded in visualizing local distortion of filaments at both PIT processed- as well as IMD processed-MgB2 wires and their influence on critical current distribution in the MgB2 wires. High resolution X-ray tomography is a powerful tool to investigate filamentary architecture and local distortion such as sausaging effect and exudation of Mg. From the magnetic image of the magnetized MgB2 wire measured by the SHPM, we could evaluate spatial distribution of local critical current density, Jc, according to Biot-Savart law. The in-field SHPM allows us to evaluate critical currents quantitatively of the MgB2 wire with magnetic sheath materials by the measurement where the external magnetic field is higher than the saturation field of the magnetic sheath [1]. The advantage of such magnetic measurements is also to evaluate high current region in which transport method is difficult to apply. Combination with the X-ray tomography and the SHPM leads abundant information on current limiting mechanism of the MgB2 wires by synergistic effect.

[1] K. Higashikawa et al., IEEE Trans. Appl. Supercond. 26 (2016) 6200804.

This study was supported by Japan Science and Technology Agency (JST) as ALCA.

Event date： 2018.4

Language：English   Presentation type：Oral presentation (general)  

Venue：理化学研究所横浜キャンパス   Country：Japan  

Event date： 2018.3

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：University of Ulsan   Country：Korea, Republic of  

Event date： 2017.12

Language：English   Presentation type：Oral presentation (general)  

Venue：九州大学伊都キャンパス   Country：Japan  

Event date： 2017.12

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：Iino Hall & Conference Center   Country：Japan  

Current-Voltage (I-V) characteristic is one of the most fundamental properties of superconducting materials for practical applications. While the I-V characteristics are usually measured by using a short piece sample and/or a micro-bridge, practical applications require long length tapes in hundreds of meters to several kilo-meters. Spatial homogeneity becomes an important issue in such cases because the minimum Ic will limit the total performance of the full-length of the tape. Therefore, Ic in the long length tape has been studied significantly as a function of longitudinal coordinate. However, it is not yet fully understood the relationship between the local Ic variation and the global I-V characteristics. In this study, we have investigated current transport properties in long length coated conductors (CCs) based on coupled analysis using reel-to-reel high-speed scanning Hall probe microscopy and site-specified transport measurements. An analytical model to describe the relationship between the local Ic variation and the global I-V characteristics in such long length CCs have been proposed. Furthermore, we will discuss a method to increase reliability, robustness and current carrying capability of the CCs under the influence of spatial Ic variation.

Acknowledgements: This work was supported by “JSPS KAKENHI (16H02334)” and “NEDO”.

Event date： 2017.12

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：産業技術総合研究所 つくば中央共用講堂   Country：Japan  

Event date： 2017.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Miyazaki Kanko Hotel   Country：Japan  

Event date： 2017.11

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡工業大学   Country：Japan  

Event date： 2017.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Maison Glad Hotel Jeju   Country：Korea, Republic of  

Magnetic moment in coated conductor (CC) tape is an important issue from both fundamental and application point of view. Because of its flat monolithic architecture, a large magnetic moment is induced in the superconducting layer against perpendicular magnetic field component to the tape surface. Furthermore, such magnetic moment will decay significantly due to flux creep. These influence spatial homogeneity and temporal stability of magnetic field in CC based magnet windings. However, we can also use such magnetic moment to evaluate crucial electromagnetic parameters such as critical currents of the CC with non-contact and non-destructive manner. In typical measurements using magnetometer such as MPMS and VSM, we measure magnetic moment of the whole sample using pick up coil. We can collect, however, much more detailed information if we measure local magnetic field profile in the sample. In this study, we have investigated magnetic moment and its relaxation by use of Hall probe magnetometry. From the time dependent field distribution across the tape width, time evolution of local electric field distribution and a decay of shielding current were obtained based on Faraday’s law and Biot-Savart law, respectively. The results were also compared with that of critical state model and flux creep. One of the important advantages of the Hall probe measurement is to obtain the data including initial state of the flux creep less than 0.1 sec not only the long time relaxation. From these analysis, we have succeeded in obtaining electric field vs. critical current density (E-J) characteristics in the CC over 4 decades of electric fields from 10-6 to 10-10 V/m. Theoretical background for the derivation and comparison with other measurements such as four probe transport measurements and MPMS will be discussed.

Acknowledgment: This work was supported by JSPS: KAKENHI (16H02334).

Event date： 2017.10

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Changwon National University   Country：Korea, Republic of  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：海洋電子工業（株）東京事務所7F会議室   Country：Japan  

Event date： 2017.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡国際会議場・福岡国際センター・福岡サンパレス   Country：Japan  

Event date： 2017.8 - 2017.9

Language：English   Presentation type：Oral presentation (general)  

Venue：RAI - Amsterdam   Country：Netherlands  

Event date： 2017.8

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：Phoenix Seagaia Resort,   Country：Japan  

Event date： 2017.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：全日通霞ヶ関ビルディング   Country：Japan  

Present status and future prospects of REBCO superconducting wire development have been discussed. In-field critical current (Ic) of REBCO can be increased significantly by introducing artificial pinning centers, i.e., the effectiveness of the APC is the advantage of REBCO. Enhancement of in-field Ic would be a key factor to reduce technical cost of the CCs. However, it should be noted that the influence of flux creep suppresses the attainable Ic at low electric field region which becomes relevant especially in DC magnet application such as NMR and MRI. Uniformity of the Ic in long length CCs is also influenced by the APC addition. Modeling of current transport properties under the influence of thermal fluctuation and spatial Ic variation in long length wires has been developed. From the analysis,it has been shown that PLD has a good potential for the production of homogeneous REBCO in long length. Flux pinning behavior is quite stable and reproducible. This suggests that the nano-scale microstructures are reproducible in the process, whereas a macroscopic defects cause spatial variation of effective cross section area in a long length tape. Beyond the critical current, realization of such architecture as narrower-tape-width, multi-filamentary and Roebel tape strand would become next issues for practical power applications.

Event date： 2017.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Moana Terrace   Country：United States  

In-field current transport property is one of the most important properties of high Tc superconducting tapes for practical applications. Usually the current-voltage (I-V) characteristics or critical current (Ic) are characterized by the four probe transport measurement or magnetization measurement using a short piece sample. In a practical application, however, the piece length of the tape strands reach more than hundreds of meters or km scale. This indicates that the influence of positional variation of Ic should also be taken into account to describe the I-V characteristics in a real device. In fact, the characterization of spatial Ic variation attracts much attention as a quality control of the long length tapes. However, the relationship between the spatial Ic variation and the local- and/or global-I-V characteristics are not well established. In this study, we have succeeded in measuring in-field Ic variation as a function of longitudinal coordinate, x, in reel-to-reel manner under external magnetic fields up to 4 T at 77 K and 65 K, respectively. We also obtained position-dependent I-V characteristics by site specified transport measurements using the same sample. We proposed an analytical model to describe the position-dependent I-V characteristics based on the Ic(x) in the long length tape. It has been shown that the analytical expression shows good agreement with the position-dependent in-field transport measurements. Namely, this approach allows us to describe the I-V characteristics as function of B, T, and x including position dependent n-index and localized flux flow dissipation in the long length tape.

Acknowledgements: This work was supported by “JSPS KAKENHI (16H02334)”.

Event date： 2017.3 - 2017.4

Language：English   Presentation type：Oral presentation (invited, special)  

Venue：Dept. of Materials Science and Engineering, Seoul National Univ., Seoul   Country：Korea, Republic of  

Development of Forefront Superconducting Materials for Next Generation Electric Energy Systems

Takanobu Kiss
Dept. of Electrical Engineering, Kyushu University, Fukuoka 819-0395, JAPAN

Superconducting materials can curry more than hundreds of times larger currents than that of normal conductors such as copper and aluminum with almost no dissipation. This allows us to realize high field magnets and/or high current cables. Indeed, superconducting technologies have already been utilized widely in such systems ad MRI, NMR, accelerator and nuclear fusion reactor. In the conventional superconducting devices, however, operation temperature is limited close to 4.2 K or lower realized with liquid helium. Namely, it requires complicated- and expensive-cooling systems. This prevents industrial applications of the superconducting technologies so far. Recent significant progress of cuprate superconductor tapes, however, have opened a new era of the superconducting technologies for industrial applications. This year is the 30 years anniversary of the discovery of Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O superconductors both exhibit superconductivity in liquid nitrogen temperature (77 K), i.e., critical-temperature (Tc) are >90 K, and >110 K, respectively. After the 30 years research and development, high performance long wires have been marketed. In this lecture, I will talk about the recent progress of high Tc cuprate superconductor tapes and their electric-power device applications. Challenges in other potential materials will also be mentioned. Our study focuses on understanding and resolving key performance issues of these forefront superconducting materials and their application to the advanced electric energy systems. Perspectives of these studies are to lead breakthrough to energy-efficiency solutions in electric grid systems, alternative energy and transportation systems.

Event date： 2016.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo International Forum   Country：Japan  

Event date： 2016.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Tsushima Civic Center, Tsushima   Country：Japan  

Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Victoria University of Wellington, Wellington   Country：New Zealand  

Event date： 2016.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Kanazawa Kageki-za, Kanazawa   Country：Japan  

Spatial homogeneity of critical current density, Jc, is one of the most important requirements for practical coated conductors (CCs). Indeed, longitudinal Jc variation is usually characterized in a commercial CC by such method as reel-to-reel transport measurement and magnetization measurement by use of Hall-probe array as a typical method. However, the limiting factor of the positional Jc variation is not yet fully under stood because most of these measurements are essentially one-dimensional measurements. Namely, the spatial resolution along the transverse direction is not enough. Moreover, the behavior at in-field and lower temperature condition is relevant issue since most of the characterization so far is at around self-field (s.f.) and 77 K. In this study, we investigated in-plane distribution of local Jc in long CCs tape by reel-to-reel magnetic microscopy. From statistical analysis of the Jc distribution, we found that the probability density function shows a non-Gaussian type asymmetric distribution. Furthermore, the central limit theorem doesn’t hold. Based on these analysis, we proposed a multi-scale model to describe global current-voltage characteristics. We also succeeded in obtaining in-field Jc distribution up to 3 T of external magnetic field. From the in-field measurements, we investigated the influence of processing for artificial pinning center (APC) addition. The relative standard deviation increases slightly in the case we added APC as shown in Fig. 1. The influence of external magnetic field on the correlation between Jc at 77 K and that of lower temperature has also been studied. Lastly, the in-plane characterization in more complicated tape architectures such as multi-filamentary tape and Roebel strands has been carried out. Microstructural origin of current blocking obstacles has been investigated by site-specified analysis combined with the magnetic microscopy and X-ray micro-tomography.

Event date： 2016.9

Language：English   Presentation type：Oral presentation (general)  

Venue：NIST, Boulder, CO,   Country：United States  

Event date： 2016.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Aspen Meadows Resort, Aspen, CO   Country：United States  

Spatial homogeneity of superconducting properties such as critical current, Ic, n-index, effective tape (or filament) width is one of the most important requirements in coated conductors (CCs) as a reliable engineering materials. For example, a local Ic drop results in a significant enhancement of local electric field, which is several orders higher than that of average value, due to nonlinear current-voltage (I-V) characteristics. Indeed, we can often see an attached data sheet on spatial Ic variation as well as end-to-end Ic value at 77 K for a recent commercial long CC products. Several characterization techniques are proposed in a reel-to-reel manner for spatially resolved measurements of Ic in a long CC. Typically we can classify into two groups, i.e., transport measurement and magnetization measurements, and the latter can be divided into several methods including magneto optical imaging (MOI), Hall-probe array method (TapeStarTM), and scanning Hall-probe microscopy (SHPM). These characterization is relevant as a fundamental quality control for the CCs. However, each technique has quite different spatial resolution (along tape width or longitudinal direction) and electric-field criterion. As a result, the relationship among Ic values obtained by these methods is not yet fully understood. This means that the definition of the spatial homogeneity by using these measurements is not clear neither. Relationship between self-field (s.f.) Ic at 77 K and in-field Ic at low temperature is further important issue because the operation condition of the CCs is not usually 77 K, s.f. whereas lower temperature and higher field. In this talk, I will summarize reel-to-reel characterization techniques on critical currents in long CCs and discuss the influence of spatial resolution, sample length, and electric-field criterion. From the analysis of statistical behavior of the Ic distribution we found that the central limit theorem doesn’t hold in the case of CCs. This is a significant difference from a standard system which can be described by the Gaussian distribution, and must be originated from a strong non-linear relationship of the flux pinning which follows a threshold logic. We also derived a model to describe I-V characteristics, therefore positional variation of n-index, based on the local Ic variation. Validity of the model has been confirmed by the site-specified transport measurements. From in-field measurements on positional Ic variation up to 3 T of perpendicular field, we also show the influence of external magnetic on the correlation between 77 K Ic and low temperature Ic. Such in-field measurement has a good potential as a characterization method to optimize process conditions for nano-structured CCs with artificial pinning centers. Lastly, I will discuss the importance of 2-dimensional characterization of Ic distribution in processed tapes such as multi-filamentary tapes and Roebel strands for advanced applications. These results would be also important issues to be considered for standardization of the Ic characterization in long CCs.

Event date： 2016.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Colorado Convention Center   Country：United States  

Spatial homogeneity is one of the most important requirements for forefront superconducting tapes and wires. To screen out local Ic deterioration in long length HTS tapes, reel-to-reel transport measurement is often adopted with a voltage tap distance of around 1 m in commercial long tapes. In fact, recent commercial products achieved good longitudinal homogeneity with a standard deviation less than 1 % in a piece length of hundreds of meters. For a higher spatial resolution such as 1 mm or less, Hall probe array method is also often applied. They are both fast and useful diagnostic tools, however, essentially 1-dimensional measurements. Therefore, it is not possible to determine an in-plane position of a localized obstacles in the tape. Furthermore, no non-contact method is applicable so far for an iron-sheathed MgB2 round wire because of the magnetization of the sheath material. In this study, we carried out spatially resolved measurements on in-plane Ic drop in a long length RE-123 tape and Bi-2223, both hundreds of meters in length, with high spatial resolution (33 μm in width and 830 μm in length) non-contact non-destructive manner by use of fast scanning reel-to-reel Hall probe microscopy (RTR-SHPM). We have succeeded in detecting localized Ic drop in the long length tapes even though the probability of such drop is less than 0.1 %. To visualize local Ic variation in the iron-sheathed MgB2 round wire, we adopted in-field SHPM which allows us to observe a magnetic image at higher external field than a saturation field of the iron-sheath up to 5 T. From such high field measurement, we’ve succeeded in detecting local Ic variation non-destructive manner. To further understanding of such obstacles, we also carried out microstructural analysis by use of X-ray tomography. This allows us to visualize 3-dimensional internal structure with a spatial resolution of 2 μm. Correlated study between SHPM and X-ray tomography clearly showed the origin of the Ic drop such as obstacles in the substrate, distortion of filaments and clack formation. This can be a very effective diagnostic scheme to improve process conditions for forefront superconducting tapes and wires.

Event date： 2016.9

Language：English   Presentation type：Oral presentation (general)  

Venue：Colorado Convention Center   Country：United States  

Event date： 2016.7

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：東北大学金属材料研究所２号館講堂   Country：Japan  

Event date： 2016.3 - 2016.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Phonix Convention Center   Country：United States  

Event date： 2016.3

Language：English   Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：KEPCO   Country：Korea, Republic of  

Takanobu Kiss

Event date： 2016.3

Language：English   Presentation type：Oral presentation (general)  

Venue：Manekshaw Centre, New Delhi, India   Country：India  

Event date： 2015.12

Language：English   Presentation type：Oral presentation (general)  

Venue：Ramada Plaza Jeju Hotel   Country：Korea, Republic of  

One of the most important material parameters of superconductors is in-field critical current, Ic, which is the maximum current carried without electrical resistance. While the Ic is governed essentially by nanoscale defects due to flux pinning, current blocking obstacles in longer scale typically m to hundreds of m influence significantly. Such local inhomogeneity, however, cannot be detected by the standard characterization methods such as four probe transport measurement and magnetization measurement because they are both macroscopic measurements assuming sample homogeneity. Furthermore, as an engineering materials, superconducting wires are required to be reproducible with homogeneous performance in km scale. Therefore, multi-scale analysis becomes essential for understanding and resolving key performance issues of superconducting materials. In this study, we have developed novel characterization techniques, which include low temperature laser scanning microscopy, scanning SQUID microscopy and scanning Hall probe microscopy, for spatially resolved measurements of local electromagnetic properties. These techniques allow us to visualize local distribution of electric field, current density and fluxoid dynamics of forefront superconducting materials including Bi-2223 tape, RE-123 tape, MgB2 wire, and iron-base superconductors with high spatial resolution also in long length up to hundreds of meters. Furthermore, site-specified investigation coupled with microstructural analysis such as SEM, TEM and X-ray microscopy clearly shows the current limiting mechanism. These multi-scale multi-physics analyses are very useful to improve process conditions effectively.
Acknowledgements: This work is supported by the AMED and the METI as a project of “Development of HTS Coiling Technology”, “JST: S-Innovation”, “JST: ALCA” and "JSPS: KAKENHI (24360122, 26630113).”

Event date： 2015.12

Language：English   Presentation type：Oral presentation (general)  

Venue：University of the Ryukyu   Country：Japan  

Event date： 2015.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：姫路商工会議所   Country：Japan  

Event date： 2015.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Zijingang campus of Zhejiang University   Country：China  

Event date： 2015.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Tower Hall Funabori   Country：Japan  

Spatial homogeneity in long length HTS tapes is one of the most important material performances for practical applications. While in-field current transport properties have been studied widely using short piece samples, local Ic fluctuation and its influence on global current transport properties in long length HTS tapes have not been understood yet. In this study, we carried out spatially resolved Ic measurements on long length HTS tapes, both RE-123 and Bi-2223, by the combination with multiple measurements including reel-to-reel high resolution scanning Hall probe microscopy (RTR-SHPM), four-probe measurements and X-ray tomography. We have investigated statistical behavior of local Ic fluctuation, local microstructural disorder and their influence on current-voltage (I-V) characteristics in the long length HTS tapes. From the analysis over wide range of length scale, the influence of spatial resolution of the measurements and sample length have been discussed from the view point of bandwidth of the spatial frequency, f. When the sample length becomes longer than several cm, the influence of 1/f type fluctuation becomes significant whereas the fluctuation is white noise type in short piece length. It has been shown that such long period fluctuation as 1/f influences transport I-V characteristics in long length tape. Relationship between observed longitudinal Ic distribution by the RTR-SHPM and global I-V characteristics has been derived. Not only monolithic tape strands but also multi-filamentary striated tapes have been studied. Influence of filament width on the Ic fluctuation has been discussed.

Acknowledgements: This work is supported by the AMED and the METI as a project of “Development of HTS Coiling Technology”, “JST: S-Innovation” and "JSPS: KAKENHI (24360122, 26630113).”

Event date： 2015.10

Language：English   Presentation type：Oral presentation (general)  

Venue：Jeju International Convention Center   Country：Korea, Republic of  

Because of its round shape and a possible superconducting joint with the highest Tc as a metallic superconductor, MgB2 wire is one of the most promising materials to realize advanced devices such as a liquid He free MRI magnet. However, critical current density of the latest MgB2 wire is not yet high enough for practical application. Namely, it is crucial to clarify the current limiting mechanism in the round MgB2 wires. By combining low temperature scanning Hall probe microscopy (SHPM) and X-ray tomography, we have succeeded in studying correlation between spatial distribution of local critical current density, Jc, and three-dimensional (3D) microstructure of filaments in the wire with non-destructive manner. To realize spatially resolved Jc measurement on magnetic sheath wire, we adopted high field SHPM where we can obtain a magnetic image at an external field higher than the saturation field of the sheath. In parallel, internal filament structure has been investigated in a few mm range with a spatial resolution in m scale by using a high resolution X-ray tomography. 3D analysis by the tomography is powerful to understand internal microstructure of the filaments including defects, cross-sectional area and their statistical variation. Combination of these microscopies allows us to understand the origin of current limit factors such as distortion of the filaments and the difference of microstructure inside the filaments, and their relationship with processing. These analyses are very effective to improve wire performance.
This study is supported by the Japan Science and Technology Agency as Advanced Low Carbon Technology Research and Development Program (JST-ALCA) for Superconducting Systems.

Event date： 2015.10

Language：English   Presentation type：Oral presentation (general)  

Venue：COEX   Country：Korea, Republic of  

Event date： 2015.10

Language：English   Presentation type：Oral presentation (general)  

Venue：くにびきメッセ   Country：Japan  

Event date： 2015.9

Language：English   Presentation type：Symposium, workshop panel (public)  

Country：France  

Event date： 2015.9

Language：English   Presentation type：Oral presentation (general)  

Country：France  

It is well established that in-plane alignment is essential to realize high critical current density in coated conductors (CCs) because of grain connectivity. It is also relevant to realize thick film deposition for the superconducting layers to increase overall critical current. The value of in-plane alignment, Df, of the substrate template is typically around 3 to 4 degree. However, the requirement for the substrate alignment is not yet fully understood especially in thick film and its performance. In this study, we have investigated the influence of highly textured IBAD based template on the in-filed current transport properties in Gd1Ba2Cu3O7-d (GdBCO) CCs. As a result of improved selfepitaxy of the CeO2 top layer, Df of the template can be reduced as low as 1.9 degree. We compared in-field critical currents of BaHfO3 doped 1.5 um-thick PLD-GdBCO deposited on such highly textured substrate and standard one, i.e., Df is 3.5 degree. From the analysis of critical current as a function of external magnetic field and temperature, we found that normalized pinning force density curves are scaled on the same curve for both case, however, the maximum value has increased 15 to 20 % for the case of highly textured substrate. This indicates that the nano-structures of the GdBCO layer are hardly influenced by the substrates, whereas effective cross-section area can be improved because of the reduction of current blocking obstacles in the case of highly textured substrate. From SEM observation of the GdBCO surface, it has been also confirmed that outer-growth can be suppressed effectively by using the highly textured substrate. These results show that the improvement of substrate in-plane alignment is still important and effective even in the range of Df< 3 degree to enhance in-field current carrying capability of CCs. Note that, it is not originated from the well-known weak-link issue but the suppression of outer-growth in a thick film deposition for the superconducting layer.
Acknowledgements: This work is supported by the Ministry of Economy, Trade and Industry (METI) as the Project for Development of HTS Coiling Technology.

Event date： 2015.8 - 2015.9

Language：English   Presentation type：Oral presentation (general)  

Venue：ICC Jeju, Jeju   Country：Korea, Republic of  

To investigate the current limiting mechanism in a long coated conductor (CC) tape, we have developed hybrid microscopy technique combining reel-to-reel scanning Hall probe microscopy (RTR-SHPM) and X-ray microtomography (X-ray-CT). While the RTR-SHPM allows us to map a high resolution 2D critical current density (Jc) distribution in the tape surface up to 1 km of length with non-contact and non-destructive manner, the X-ray-CT can visualize 3D microstructure inside the tape with micro-meter resolution. Because the CC tape is essentially an 1D current transport media, a local bottleneck limits the performance of the whole CC tape. Namely, the bottleneck engineering becomes crucial to realize a high quality CC in a practical level. However, the present characterization techniques such as reel-to-reel transport measurement and 1D Hall mapping do not have enough spatial resolution to detect in-plane local obstacles in the tape. Furthermore, the relationship between a process condition and the limiting factor is not yet clear. In this study, we have succeeded in visualizing in-plane local Jc drop in a 200-m-long 5-mm-wide commercial GdBCO CC tape using the RTR-SHPM, that is followed by the X-ray-CT analysis to find out microstructural origin of the obstacles. Such hybrid microscopy clearly shows that the local Jc drop is originated from defects on the metal substrate. Note that this approach can cover 9 decades of multi-scale analysis from km to m range with correlating electromagnetic characterization and microstructural analysis. This is a powerful diagnostic tool to improve CC process conditions in a very effective way.

Acknowledgements: This work is supported by the Ministry of Economy, Trade and Industry (METI) as the Project for Development of HTS Coiling Technology and JSPS: KAKENHI (24360122).

Event date： 2015.8

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyushu University   Country：Japan  

Event date： 2015.8

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：ヒルズサンピア山形   Country：Japan  

酸化物高温超伝導体（HTS）は、高い臨界温度に加え、従来の金属系超伝導材料を遙かに凌駕する高磁界特性を有することから、液体ヘリウムフリーの環境下で動作可能な医療用MRIマグネットや医療用加速器用マグネットなどへの適用が期待されている。近年、磁界下の電流輸送性能の向上と共に、数100 m～km級の長尺線材が実現され、プロトタイプ機器の研究開発が国内外において加速している。
一方で、以下に述べる様な、HTS特有の問題も顕在化しており、今後の研究開発における喫緊の課題といえる。超伝導線材の実用性能を決定づける最も重要な材料パラメータは、電気抵抗ゼロで輸送できる電流の最大値（臨界電流：Ic）である。超伝導線材のIc値は、典型的には、四端子法によって試料全体の平均電界が1 uV/cm（10-4 V/m）あるいは1 uV/mに達するときの電流値として評価され、臨界電流密度Jcは超伝導領域の断面積あたりの電流密度として定義される。しかしながら、HTSの磁束フロー領域への遷移はなだらかで有り、Jc値は電界基準Ecによってかなり変化する。MRIに代表される定常磁界を用いる直流応用においては、線材内に誘起される電界は典型的には10-10 V/m以下であり、四端子法のEcに比べ何桁も小さい。高温超伝導体の電界―電流密度（E-J）特性は四端子法による測定結果よりパワー則: E(J)=Ec (J/Jc)n によって近似されることが多いが、果たしてこの様な超低電界領域においてパワー則による近似が妥当か否かについて十分に解明されていない。また、機器応用の観点からは冷熱発生や使用磁界、運転温度を最適化した設計が求められるが、電流輸送特性は温度、磁界によって複雑に変化する事から、これらを広い運転条件下において定量的に把握する事が必要である。一方、一般の商用線材の性能指標としては液体窒素温度、自己磁界下のIc値が示される場合がほとんどであり、実際の運転環境下の特性把握に対して十分応えきれていない。さらに、材料開発の観点からも、ナノ組織制御による人工ピン止め点（APC）を効率良く導入し、磁界下の電流輸送性能の向上が求められるが、広い動作条件下における定量的な特性比較が不可欠である。
HTS線材を用いた医療用超伝導マグネット開発で特に重要なのは、テープ状の線材形状に起因する問題である。マグネット巻線内の素線の幅広面に垂直印加される磁界により遮蔽電流が誘起され、すなわち、素線の磁気モーメントによるマグネット磁界の空間均一性ならびに時間的安定性に影響を及ぼす。素線の磁気モーメントの大きさは、超伝導層の線幅に比例する事から、素線の細線化やスクライビングによるマルチフィラメント加工の必要性が指摘されている。その為には、テープ線材そのものの高度な空間均一性の確保が重要となることは勿論のこと、加工プロセス技術の開発が必要である。また、巻線精度の向上のためには、テープ線幅の幾何学的な均一性は勿論のこと、電磁気的なテープ線幅の均一性が不可欠となる。一方、上述の通り、一般的なIc評価手法においては、マクロスケールの平均量として定義されているに過ぎず、上述した問題点に対する解決策は勿論のこと、その為の評価法すら十分に確立出来ていない。特に、線材は本質的には一次元の電流輸送媒体である事から明らかなとおり、最小のIc値が全体の性能を決定する。また、希土類系高温超伝導（RE-123）線材では積層プロセスを用いている事からプロセスそのものがシーケンシャルであって、高性能化のためには作製プロセスとの関連も含めた電流制限因子の解明が極めて重要となる。この事はまた、応用側からも重要な視点で有り、現状のHTS線材の不安定性をも定量的に理解した上で、設計に上手く反映させる工夫が求められよう。
本講演では、以上の様な問題意識のもと筆者等がこれまで取り組んできた、HTS線材の各種評価技術について述べると共に、これらの特性評価の視点から、HTS線材性能の現状について概説する。

Event date： 2015.6 - 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：JW Marriott Starr Pass Resort & Spa, Tucson, Arizona   Country：United States  

Spatial homogeneity of critical current, Ic, is one of the most important performances of practical HTS tapes. Such Ic homogeneity is typically characterized by the reel-to-reel transport measurement with a tap distance of several tens cm to several m. However, the spatial resolution is not enough in the conventional method to detect local Ic drop, especially in the case of Bi-2223 tape because of a small shunt resistance of the Ag sheath. In this study, we have succeeded in measuring in-plane Ic distribution in a commercial 100-m-class Bi-2223 tape with non-contact and non-destructive manner by using reel-to-reel high speed scanning Hall probe microscopy. This allows us to measure high resolution remanent flux image on the tape surface in liquid nitrogen bath with a spatial resolution of 34 um in width and 830 um in length. Traveling speed of the tape during the measurement was 36 m/h at maximum. By solving the inversion problem, we obtained in-plane Ic distribution in the tape. We have succeeded in analyzing Ic fluctuation over multi-scale length more than 5 decades. To check the validity of the Ic value, we also carried out site-specified four-probe measurements, then confirmed that these two measurements showed good agreement each other. Statistical behavior of the Ic fluctuation and the correlation with microstructure will be discussed.

Acknowledgements: This study was supported by the “JST: S-Innovation” and "JSPS: KAKENHI (24360122)”.

Event date： 2015.3

Presentation type：Oral presentation (general)  

Venue：東海大学 湘南キャンパス, 神奈川県平塚市   Country：Japan  

Event date： 2014.12

Presentation type：Oral presentation (general)  

Venue：九州大学　西新プラザ, 福岡市   Country：Japan  

Event date： 2014.12

Presentation type：Oral presentation (general)  

Venue：Changwon National University, Changwon,   Country：Korea, Republic of  

Event date： 2014.11 - 2014.12

Presentation type：Oral presentation (general)  

Venue：Jeju Grand Hotel, Jeju,   Country：Korea, Republic of  

Event date： 2014.11

Language：English   Presentation type：Oral presentation (general)  

Venue：Tower Hall Funabori, Tokyo,   Country：Japan  

Event date： 2014.11

Presentation type：Oral presentation (general)  

Venue：コラッセふくしま, 福島市   Country：Japan  

Event date： 2014.9

Presentation type：Oral presentation (general)  

Venue：北海道大学, 札幌市   Country：Japan  

Event date： 2014.8

Presentation type：Oral presentation (general)  

Venue：Fukuoka University, Fukuoka   Country：Japan  

Event date： 2014.8

Presentation type：Oral presentation (general)  

Venue：Charlotte Convention Center, North Carolina   Country：United States  

Event date： 2014.8

Presentation type：Oral presentation (general)  

Venue：Charlotte Convention Center, North Carolina   Country：United States  

Event date： 2014.8

Presentation type：Oral presentation (general)  

Venue：Charlotte Convention Center, North Carolina   Country：United States  

Event date： 2014.7

Presentation type：Oral presentation (general)  

Venue：JST東京本館B1大会議室   Country：Japan  

Event date： 2014.4 - 2014.5

Presentation type：Oral presentation (general)  

Venue：Kervansaray Lara Resort Hotel, Antalya   Country：Turkey  

Event date： 2014.3

Presentation type：Oral presentation (general)  

Venue：青山学院大学相模原キャンパス   Country：Japan  

Event date： 2014.2

Presentation type：Oral presentation (general)  

Venue：The Moscone Center, Room 125, San Francisco, CA   Country：United States  

Event date： 2014.1

Presentation type：Oral presentation (general)  

Venue：DoubleTree by Hilton Orlando at Sea World, Orlando, Fla.   Country：United States  

Event date： 2014.1

Presentation type：Oral presentation (general)  

Venue：北九州国際会議場   Country：Japan  

Event date： 2013.11

Language：English   Presentation type：Oral presentation (general)  

Venue：タワーホール船堀   Country：Japan  

Event date： 2013.10

Presentation type：Oral presentation (general)  

Venue：Perissia Hotel, Cappadocia   Country：Turkey  

Event date： 2013.9

Presentation type：Oral presentation (general)  

Venue：Genova   Country：Italy  

Event date： 2013.9

Presentation type：Oral presentation (general)  

Venue：Magazzini del Cotone Conference Center, Genova   Country：Italy  

Event date： 2013.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Toki Messe   Country：Japan  

Event date： 2013.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Univ. of Dayton Research Instiute, Dayton, OH   Country：United States  

Event date： 2013.6

Presentation type：Oral presentation (general)  

Venue：Dena'ina Civic and Convention Center, Anchorage, Alaska   Country：United States  

Event date： 2013.4

Language：English   Presentation type：Oral presentation (general)  

Venue：Moscone West Convention Center/Marriott Marquis, San Francisco, California   Country：United States  

Event date： 2013.3

Presentation type：Oral presentation (general)  

Venue：神奈川工科大学   Country：Japan  

Event date： 2013.2

Presentation type：Oral presentation (general)  

Venue：古河電工健康保険組合　鬼怒川荘   Country：Japan  

Event date： 2013.1

Presentation type：Oral presentation (general)  

Venue：DoubleTree by Hilton Orlando at Sea World, Orlando, Fla.   Country：United States  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：Jeju   Country：Korea, Republic of  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：広島工業大学   Country：Japan  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2012.3

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：鹿児島大学   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：鹿児島大学   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：金沢歌劇座   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：金沢歌劇座   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：金沢歌劇座   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：金沢歌劇座   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：金沢歌劇座   Country：Japan  

Event date： 2011.11

Presentation type：Oral presentation (general)  

Venue：金沢歌劇座   Country：Japan  

Event date： 2011.10

Presentation type：Oral presentation (general)  

Venue：Sumitomo Club and Osaka Works of Sumitomo Electric Industries, Ltd.   Country：Japan  

Event date： 2011.10

Presentation type：Oral presentation (general)  

Venue：Tower Hall Funabori   Country：Japan  

Event date： 2011.10

Presentation type：Oral presentation (general)  

Venue：Tower Hall Funabori   Country：Japan  

Event date： 2011.10

Presentation type：Oral presentation (general)  

Venue：Tower Hall Funabori   Country：Japan  

Event date： 2011.10

Presentation type：Oral presentation (general)  

Venue：Tower Hall Funabori   Country：Japan  

Event date： 2011.10

Presentation type：Oral presentation (general)  

Venue：Muju   Country：Korea, Republic of  

韓国超電導・低温工学会2011年度年次大会(The Korea Institute of Applied Superconductivity and Cryogenics Conference 2011
Oct. 13-14, Muju, Korea)において、「日本における希土類系高温超電導線材と応用機器開発の進展」と題する招待講演を行った。本講演は、経済産業省の主導するイットリウム系超電導電力機器技術開発プロジェクト(2008-2012年度)の中核メンバの一人として招聘を受けたものであり、筆者の従事する先進超電導線材の基盤技術開発と機器応用に関する最新動向と将来展望に関するレビューを行った。

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：佐賀大学 本庄キャンパス   Country：Japan  

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：佐賀大学 本庄キャンパス   Country：Japan  

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：the World Forum Conference Centre   Country：Netherlands  

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：the World Forum Conference Centre   Country：Netherlands  

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：the World Forum Conference Centre   Country：Netherlands  

Event date： 2011.9

Presentation type：Oral presentation (general)  

Venue：the Congress Center of the Parc Chanot   Country：France  

Event date： 2011.8 - 2011.9

Presentation type：Oral presentation (general)  

Venue：山形大学 小白川キャンパス   Country：Japan  

Event date： 2011.8 - 2011.9

Presentation type：Oral presentation (general)  

Venue：山形大学 小白川キャンパス   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：沖縄県　健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：健康文化村 カルチャーリゾート フェストーネ   Country：Japan  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：Ruhr-University Bochum   Country：Germany  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：Ruhr-University Bochum   Country：Germany  

Event date： 2011.7

Presentation type：Oral presentation (general)  

Venue：Ruhr-University Bochum   Country：Germany  

Event date： 2011.6

Presentation type：Oral presentation (general)  

Venue：Spokane, Washington   Country：United States  

Event date： 2011.5

Presentation type：Oral presentation (general)  

Venue：物質・材料研究機構   Country：Japan  

Event date： 2011.5

Presentation type：Oral presentation (general)  

Venue：物質・材料研究機構   Country：Japan  

Event date： 2011.5

Presentation type：Oral presentation (general)  

Venue：物質・材料研究機構   Country：Japan  

Event date： 2011.5

Presentation type：Oral presentation (general)  

Venue：物質・材料研究機構   Country：Japan  

Event date： 2010.12

Presentation type：Oral presentation (general)  

Venue：かごしま県民交流センター   Country：Japan  

Event date： 2010.12

Presentation type：Oral presentation (general)  

Venue：かごしま県民交流センター   Country：Japan  

Event date： 2010.12

Presentation type：Oral presentation (general)  

Venue：かごしま県民交流センター   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：九州大学 伊都キャンパス   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：九州大学 伊都キャンパス   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：九州大学 伊都キャンパス   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：九州大学 伊都キャンパス   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2010.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：東京大学 武田ホール   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：Fukuoka Soft Research Park Center   Country：Japan  

Event date： 2010.9

Presentation type：Oral presentation (general)  

Venue：長崎大学   Country：Japan  

Event date： 2010.9

Presentation type：Oral presentation (general)  

Venue：長崎大学   Country：Japan  

Event date： 2010.9

Presentation type：Oral presentation (general)  

Venue：長崎大学   Country：Japan  

Event date： 2010.9

Presentation type：Oral presentation (general)  

Venue：長崎大学   Country：Japan  

Event date： 2010.9

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：九州大学 伊都キャンパス   Country：Japan  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.8

Presentation type：Oral presentation (general)  

Venue：Omni Shoreham Hotel   Country：United States  

Event date： 2010.7

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：University of Malaysia Sabah   Country：Malaysia  

Event date： 2010.7

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：University of Malaysia Sabah   Country：Malaysia  

Event date： 2010.7

Presentation type：Oral presentation (general)  

Venue：Yongpyong Resort   Country：Korea, Republic of  

Event date： 2010.6

Presentation type：Oral presentation (general)  

Venue：九州電力（株）総合研究所   Country：Japan  

Event date： 2010.5

Presentation type：Oral presentation (general)  

Venue：川崎市産業振興会館   Country：Japan  

Event date： 2010.5

Presentation type：Oral presentation (general)  

Venue：川崎市産業振興会館   Country：Japan  

Event date： 2010.5

Presentation type：Oral presentation (general)  

Venue：川崎市産業振興会館   Country：Japan  

Event date： 2010.5

Presentation type：Oral presentation (general)  

Venue：川崎市産業振興会館   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：東海大学 湘南キャンパス   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：東海大学 湘南キャンパス   Country：Japan  

Event date： 2010.3

Presentation type：Oral presentation (general)  

Venue：明治大学   Country：Japan  

Event date： 2009.12

Presentation type：Oral presentation (general)  

Venue：核融合科学研究所   Country：Japan  

Event date： 2009.12

Presentation type：Oral presentation (general)  

Venue：National High Magnetic Field Laboratory, Florida   Country：United States  

Event date： 2009.12

Presentation type：Oral presentation (general)  

Venue：Kunibiki Messe, Matue   Country：Japan  

Event date： 2009.12

Presentation type：Oral presentation (general)  

Venue：Kunibiki Messe, Matue   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Hotel Catalonia Ramblas, Barcelona   Country：Spain  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Hotel Catalonia Ramblas, Barcelona   Country：Spain  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Hotel Catalonia Ramblas, Barcelona   Country：Spain  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Hotel Catalonia Ramblas, Barcelona   Country：Spain  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：熊本大学   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：熊本大学   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：岡山大学創立50周年記念館   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：岡山大学創立50周年記念館   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：岡山大学創立50周年記念館   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：岡山大学創立50周年記念館   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2009.11

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：九州工業大学   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：九州工業大学   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：TU Dresden Auditorium Centre   Country：Germany  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：TU Dresden Auditorium Centre   Country：Germany  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：仙台市　秋保温泉「緑水亭」   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：富山大学   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：富山大学   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：富山大学   Country：Japan  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：京王プラザホテル   Country：Japan  

Event date： 2009.8

Presentation type：Oral presentation (general)  

Venue：九州工業大学   Country：Japan  

Event date： 2009.6

Presentation type：Oral presentation (general)  

Venue：JST三番町１階会議室   Country：Japan  

Event date： 2009.5

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2009.5

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2009.5

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2009.5

Presentation type：Oral presentation (general)  

Venue：早稲田大学   Country：Japan  

Event date： 2009.3 - 2009.4

Presentation type：Oral presentation (general)  

Venue：つくば大学   Country：Japan  

Visualization of the current distribution in multi-filamentary model samples by using the Hall-probe microscopy

Event date： 2009.3 - 2009.4

Presentation type：Oral presentation (general)  

Venue：つくば大学   Country：Japan  

Critical current property of mixed-system RE123 coated conductors fabricated by TFA-MOD process

Event date： 2009.3

Presentation type：Oral presentation (general)  

Venue：北海道大学   Country：Japan  

Investigation of Hysteretic Characteristics in Multifilamentary Model Sample of YBCO Coated Conductor by Means of Magnetic Microscopy and Numerical Analysis

Event date： 2008.12

Presentation type：Oral presentation (general)  

Venue：The Hilton University of Houston,   Country：United States  

Critical currents and AC losses in coated conductors

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：宮崎大学   Country：Japan  

Visualization of nonuniform current flow around a defect-repair-splicing in RE123 coated conductor

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Estimation of in-plane thermal diffusivity in YBCO bi-crystalline thin film by use of the low temperature laser scanning microscopy

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Electromagnetically-thermally-structurally coupled analysis of high-field magnet coil taking account of current transport characteristics in GdBCO coated conductor as a function of temperature， magnetic field， its angle and mechanical strain

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Temperature，magnetic field and field angle dependence of critical current property in long length GdBCO coated conductor fabricated by RTR processcrossover regime

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Detection of inter-grain Jc at low angle bi-crystalline YBCO film across magnetic field induced crossover regime

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Current distribution at repair joints made by silver diffusion soldering

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Estimation of in-field axial strain dependence in RE123 coated conductors

Event date： 2008.11

Presentation type：Oral presentation (general)  

Venue：高知市文化プラザかるぽーと   Country：Japan  

Visualization of current profile in multi-filamentary model samples by the scanning Hall probe magnetic microscopy

Event date： 2008.10 - 2008.12

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Visualization of non-uniform current flow in coated conductors by scanning hall-probe magnetic microscopy

Event date： 2008.10 - 2008.12

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Comprehensive analysis of current transport properties in RE1Ba2Cu3O7-d(RE=Y, Gd) coated conductors

Event date： 2008.10 - 2008.12

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Significant reduction in volume, stored energy and magnetization loss of high-field magneto coil based on the improvement of critical current characteristics in GdBCO coated conductor

Event date： 2008.10 - 2008.12

Presentation type：Oral presentation (general)  

Venue：Tsukuba International Congress Center   Country：Japan  

Critical current property in YBCO coated conductor fabricated by improved TFA-MOD process

Event date： 2008.9

Presentation type：Oral presentation (general)  

Venue：大分大学   Country：Japan  

Event date： 2008.9

Presentation type：Oral presentation (general)  

Venue：北海道工業大学   Country：Japan  

Event date： 2008.9

Presentation type：Oral presentation (general)  

Venue：北海道工業大学   Country：Japan  

Event date： 2008.8

Presentation type：Oral presentation (general)  

Venue：the Washington State Convention and Trade Center, Seattle, WA, USA   Country：United States  

The use of LTLSM for estimating in-plane thermal diffusivity in YBCO thin films

Event date： 2008.8

Presentation type：Oral presentation (general)  

Venue：the Washington State Convention and Trade Center, Seattle, WA, USA   Country：United States  

Coupled analysis method for high-field magnet coil using coated conductor based on J-E characteristics as a function of temperature, magnetic field vector and mechanical strain

Event date： 2008.8

Presentation type：Oral presentation (general)  

Venue：the Washington State Convention and Trade Center, Seattle, WA, USA   Country：United States  

Observation of current distribution in high-Tc superconducting tape by using scanning hall-probe microscope

Event date： 2008.8

Presentation type：Oral presentation (general)  

Venue：the Washington State Convention and Trade Center, Seattle, WA, USA   Country：United States  

Current transport in (001)-tilted YBCO bicrystalline film under the influence of external magnetic field

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：大濱信泉記念館   Country：Japan  

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：大濱信泉記念館   Country：Japan  

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：大濱信泉記念館   Country：Japan  

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：大濱信泉記念館   Country：Japan  

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：大濱信泉記念館   Country：Japan  

Event date： 2008.7

Presentation type：Oral presentation (general)  

Venue：大濱信泉記念館   Country：Japan  

Event date： 2008.5

Presentation type：Oral presentation (general)  

Venue：千葉大学   Country：Japan  

Transport characteristics in Bi2223 wire fabricated by CT-OP process

Event date： 2008.5

Presentation type：Oral presentation (general)  

Venue：千葉大学   Country：Japan  

Current transport in micro-filamentary and defect-repair-joining RE123 tapes

Event date： 2008.5

Presentation type：Oral presentation (general)  

Venue：千葉大学   Country：Japan  

Development of scanning Hall-probe microscope for the analysis of current transport in HTS tapes

Event date： 2008.5

Presentation type：Oral presentation (general)  

Venue：千葉大学   Country：Japan  

Overview of Development of Optimal Design Method for SMES Coil Using MOCVD-YBCO Conductor

Event date： 2008.5

Presentation type：Oral presentation (general)  

Venue：千葉大学   Country：Japan  

Potential of High-Field Magnet Based on Critical Current Characteristics in Long GdBCO Coated Conductor

Event date： 2008.3 - 2008.7

Presentation type：Symposium, workshop panel (public)  

Country：Japan  

Event date： 2008.3

Presentation type：Oral presentation (general)  

Venue：福岡工業大学   Country：Japan  

Event date： 2008.3

Presentation type：Oral presentation (general)  

Venue：電力中央研究所第一会議室   Country：Japan  

Presentation type：Oral presentation (general)  

Country：Japan  

T.Kiss, On the possibility of an alternative explanation of vortex glass-liquid transition (Invited), International Seminar on Superconducting State and Transport Phenomena in High Magnetic Fields, 1995.05.

Presentation type：Oral presentation (general)  

Country：Japan  

Presentation type：Oral presentation (general)  

Country：Japan  

Presentation type：Oral presentation (general)  

Country：Japan  

T. Kiss, T. Nakamura, M. Takeo, F. Irie, K. Yamafuji, Transport Characteristics in High T$_{c}$ Superconductors with Pin Fluctuation under The Influence of Thermal Agitation (invited), 8th Int. Workshop on Critical Current in Superconductors, 1996.05.

Presentation type：Oral presentation (general)  

Country：Japan  

T. Kiss, K. Yamafuji, Glass-Liquid Transition and Flux Pinning in High T$_{c}$ Superconductors (invited), Int. Workshop on New Phys. in the Vortex State of the High Temp. Superconductors, 1996.04.

Presentation type：Oral presentation (general)  

Venue：Madison   Country：United States  

T. Kiss, T. Matsushita, F. Irie, Relationship among flux depinning, irreversibility and phase transition in a disordered HTS material (invited), The 9th International Workshop on Critical Currents (IWCC9-99), 1999.07.

Presentation type：Oral presentation (general)  

Venue：東京都 東京大学   Country：Japan  

T. Kiss, M. Inoue, K. Imamura, H. Tokutomi, T. Shoyama, A. Ibi, T. Watanabe, Y. Yamada, Y. Shiohara, Imaging of non-uniform flux flow dissipation in YBCO/IBAD coated conductor under the influence of high magnetic field, CSJ Conference, Vol. 72 (2005), 2005.05.

Presentation type：Oral presentation (general)  

Venue：Moscone West in San Francisco, California   Country：United States  

Takanobu Kiss, Imaging and Characterization of Nonuniform Current Transport in YBCO Coated Tapes (invited), MRS Spring meeting, 2005.04.

Presentation type：Oral presentation (general)  

Venue：京都府京都市　京都大学　吉田キャンパス時計台記念館第３会議室   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Takanobu Kiss, Spatially resolved measurements of local electromagnetic properties in YBCO coated conductors, US-Japan collaboration project on AC loss study of HTS conductor, 2005.03.

Presentation type：Oral presentation (general)  

Venue：兵庫県尼崎市　岩谷瓦斯（株）尼崎工場   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Miyazaki   Country：Japan  

T. Kiss, M. Inoue, H. Tokutomi, T. Shoyama, S. Koyanagi, K. Imamura, M. Takeo, J. Matsuda, T. Izumi, Y. Shiohara, Influence of current limiting obstacles and nonlinear current flow in YBCO coated conductors, Asian Conference 2004 on Applied Superconductivity and Cryogenics (ACASC2004), 2004.11.

Presentation type：Oral presentation (general)  

Venue：Niigata   Country：Japan  

T. Kiss, M. Inoue, H. Tokutomi, S. Koyanagi, T. Shoyama, M. Takeo, Y. Shiohara, Nonlinear current flow around transverse defects in YBCO thin film, The 17th International Symposium on Superconductivity (ISS2004), 2004.11.

Presentation type：Oral presentation (general)  

Venue：Niigata   Country：Japan  

Takanobu Kiss, Recent topics on advances characterization of transport current in coated conductors (Invited), The 17th International Symposium on Superconductivity (ISS2004), 2004.11.

Presentation type：Oral presentation (general)  

Venue：Oiso Prince Hotel, Kanagawa   Country：Japan  

Takanobu Kiss, Microanalysis of superconducting properties in YBCO coated conductors (Invited), International workshop on coated conductors for applications, CCA 2004, 2004.11.

Presentation type：Oral presentation (general)  

Venue：Jacksonville, FL   Country：United States  

T. Kiss, M. Inoue, M. Yasunaga, H. Tokutomi, Y. Iijima, K. Kakimoto, T. Saitoh, Y. Tokunaga, T. Izumi, Y. Shiohara, Low temperature scanning laser microscopy of YBCO coated IBAD tapes, Applied Superconductivity Conference, ASC 2004, 2004.10.

Presentation type：Oral presentation (general)  

Venue：Hyatt Regency Kinabalu, Kota Kinabalu Sabah   Country：Malaysia  

Takanobu Kiss, Current Transport Properties in High-Temperature Superconducting Composites (Invited Keynote), The XXI Regional Conference and Workshop on Solid State Science & Technology, 2004.10.

Presentation type：Oral presentation (general)  

Venue：Oak Ridge, Tennessee   Country：United States  

T. Kiss, M. Inoue, H. Tokutomi, R. Okamoto, T. Shoyama, T. Imamura, Y. Iijima, K. Kakimoto, T. Saitoh, J. Matsuda, T. Izumi, and Y. Shiohara, Fundamental characteristics, US-Japan Collaboration: AC Loss Workshop, 2004.09.

Presentation type：Oral presentation (general)  

Venue：福岡県福岡市　九州大学   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：神奈川県藤沢市　ＫＫＲ片瀬ニュー向洋   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：宮城県仙台市　東北学院大学   Country：Japan  

T. Kiss, M. Inoue, K. Imamura, S. Koyanagi, M. Takeo, Y. Iijima, K. Kakimoto, T. Saitoh, Y. Shiohara, Imaging of trapped vortices in a YBCO coated conductor by scanning SQUID microscopy, The 65th Autumn Meeting, 2004; The Japan Society of Applied Physics, 2004.09.

Presentation type：Oral presentation (general)  

Venue：東京江東区東雲　超電導工学研究所   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：横浜市　横浜国立大学   Country：Japan  

T. Kiss, Y. Murakami, R. Okamoto, S. Koyanagi, M. Inoue, M. Takeo, Y. Iijima, K. Kakimoto, T. Saitoh, Y. Shiohara, Laser imagining of local inhomogeneity in YBCO tapes covered by Ag-stabilization layer, CSJ Conference, Vol. 70 (2004), 2004.05.

Presentation type：Oral presentation (general)  

Venue：Indiana Convention Center & RCA Dome, Indianapolis, Indiana   Country：United States  

T. Kiss, M. Inoue, H. Tokutomi, R. Okamoto, T. Shoyama, T. Imamura, Y. Iijima, K. Kakimoto, T. Saitoh, Y. Tokunaga, T. Izumi, and Y. Shiohara, Low temperature scanning laser microscopy of YBCO coated IBAD tapes, 106th Annual Meeting, The American Ceramic Society, 2004.04.

Presentation type：Oral presentation (general)  

Venue：東京都八王子　東京工科大学   Country：Japan  

T. Kiss，M. Yasunaga, H. Tokutomi, M. Inoue, M. Takeo, Measurement and analysis of local electric field concentration around an artificial plane defect in YBCO film, The 51st Spring Meeting 2004; The Japan Society of Applied Physics and Related Scieties, 2004.03.

Presentation type：Oral presentation (general)  

Venue：Wollongong, NSW   Country：Australia  

Takanobu Kiss, Spatially resolved measurements of inhomogeneous dissipation in HTS conductors (Invited), 2004 International Cryogenic Materials Conference (ICMC) topical workshop, 2004.02.

Presentation type：Oral presentation (general)  

Venue：Beijing   Country：China  

T. Kiss, M. Inoue, M. Yasunaga, K. Imamura, T. Ohta, H. Tokutomi, Y. Tsuda, H. Sawa, M. Takeo, Y. Iijima, K. Kakimoto, T. Saitoh, Y. Tokunaga, T. Izumi and Y. Shiohara, Current transport properties in YBCO coated IBAD tapes, Asian Conference on Applied Superconductivity and Cryogenics, 2003.12.

Presentation type：Oral presentation (general)  

Venue：島根県松江市　島根県民会館   Country：Japan  

T. Kiss, M. Yasunaga, H. Tokutomi, M. Inoue, M. Takeo, Electric field distribution around a transverse defect in an epitaxial YBCO thin film, CSJ Conference, Vol. 69 (2003), 2002.12.

Presentation type：Oral presentation (general)  

Venue：函館市   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Superconductivity Research Laboratory, Tokyo   Country：Japan  

Takanobu Kiss, Fundamental Characteristics, 3rd meeting for US-Japan Collaboration Project of AC Loss, 2003.10.

Presentation type：Oral presentation (general)  

Venue：Shonan Village Center, Kanagawa   Country：Japan  

Takanobu Kiss, Spatially resolved measurements of dissipative state in HTS tapes and films by low temperature scanning laser microscopy (invited), The 11th Japan-US Workshop on High-Tc Superconductors, 2003.10.

Presentation type：Oral presentation (general)  

Venue：Anchorage, AK   Country：United States  

T. Kiss, M. Inoue, S. Egashira, M. Yasunaga, H. Tokutomi, M. Takeo, Y. Iijima, K. Kakimoto and T. Saitoh, Imaging of the local dissipation in YBCO coated tapes, Cryogenic Engineering Conference and International Cryogenic Materials Conference 2003, 2003.09.

Presentation type：Oral presentation (general)  

Venue：Sorrento, Italy   Country：Italy  

T. Kiss, M. Yasunaga, Y. Murakami, H. Tokutomi, R. Okamoto, M. Inoue, M. Takeo, Non-uniform electric field distribution around a planar defect in YBCO film and its nfluence on thermal instability, 6th European Conference on Applied Superconductivity, 2003.09.

Presentation type：Oral presentation (general)  

Venue：Orta S. Giulio, Italy,   Country：Italy  

T. Kiss, M. Inoue, M. Yasunaga, K. Imamura, T. Ohta, H. Tokutomi, Y. Tsuda, H. Sawa and M. Takeo, Current Transport Properties in a YBCO Coated IBAD Tape Made by TFA-MOD Process, International Workshop on Coated Conductors for Application 2003 (CCA 2003), 2003.09.

Presentation type：Oral presentation (general)  

Venue：東京都　日本大学   Country：Japan  

Takanobu Kiss, Transport E-J Characteristics in YBCO Coated Conductors (invited), The 11th International Workshop on Critical Currents in Superconductors (11th IWCC), 2003.07.

Presentation type：Oral presentation (general)  

Venue：超電導工学研究所   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：茨城県つくば市　産業技術総合研究所   Country：Japan  

T. Kiss, M. Inoue, M. Yasunaga, K. Imamura, T. Ohta, Y. Iijima, K. Kakimoto, T. Saitoh, , Local resistive transition in YBCO coated tapes and global E-J characteristics, CSJ Conference, Vol. 68 (2003), 2003.03.

Presentation type：Oral presentation (general)  

Venue：Austin, TX   Country：United States  

T. Kiss, Critical Current Densities: Percolation and Scaling, American Physical Society March Meeting 2003, 2003.03.

Presentation type：Oral presentation (general)  

Country：United States  

T. Kiss, M. Inoue, T. Kuga, M. Ishimaru, S. Egashira, T. Ohta, K. Imamura, M. Yasunaga, M. Takeo, T. Matsushita, Y. Iijima, K. Kakimoto, T. Saitoh, S. Awaji, K. Watanabe, Y. Shiohara, Current-voltage characteristics in YBCO coated IBAD tapes (Invited), MRS Fall meeting, 2002.12.

Presentation type：Oral presentation (general)  

Venue：Yokohama   Country：Japan  

T. Kiss, M. Inoue, T. Kuga, M. Ishimaru, S. Egashira, T. Ohta, K. Imamura, M. Yasunaga, M. Takeo, T. Matsushita, Y. Iijima, K. Kakimoto, T. Saitoh, S. Awaji, K. Watanabe, Y. Shiohara, Critical current properties in HTS tapes (Invited), International Symposium on Superconductivity(ISS) 2002, 2002.11.

Presentation type：Oral presentation (general)  

Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Gatlinburg, TN   Country：United States  

T. Kiss, M. Inoue, T. Kuga, M. Ishimaru, S. Egashira, T. Ohta, K. Imamura, M. Yasunaga, M. Takeo, T. Matsushita, Y. Iijima, K. Kakimoto, T. Saitoh, S. Awaji, K. Watanabe, Y. Shiohara, Critical currents in YBCO superconducting tapes (Invited), MRS Superconductivity Workshop: International Workshop on Processing and Applications of Superconductors, 2002.08.

Presentation type：Oral presentation (general)  

Venue：The University of Tokyo   Country：Japan  

T. Kiss, S. Nishimura, M. Inoue, H. Okamoto, Y. Sumiyoshi, T. Matsushita, Y. Iijima, K. Kakimoto, T. Saitoh, S. Awaji, K. Watanabe, Y. Shiohara, Critical current properties of high Tc superconducting tapes (Invited), US/Japan Workshop on Application of high temperature superconducting coil for fusion plasma experimental devices, 2002.02.

Presentation type：Oral presentation (general)  

Venue：Fukuoka   Country：Japan  

T. Kiss, Transport $E$-$J$ Characteristics in HTS (invited), The International Workshop on Critical Currents and Applications of HTS (IWCCA-HTS, Satellite Conf. to ISS 200), 2000.10.

Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

Takanobu Kiss, Current transport properties in YBCO coated conductors under the influence of magnetic field and mechanical strain (Invited), 3rd Workshop on Mechano-Electromagnetic Property of Composite Superconductors (MEM05), 2005.07.

Presentation type：Oral presentation (general)  

Venue：Changwon   Country：Korea, Republic of  

Presentation type：Oral presentation (general)  

Venue：San Francisco, CA   Country：United States  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Epochal Tsukuba, Tsukuba   Country：Japan  

Presentation type：Oral presentation (general)  

Country：Korea, Republic of  

Presentation type：Oral presentation (general)  

Venue：San Francisco, CA   Country：United States  

Presentation type：Oral presentation (general)  

Venue：San Francisco, CA   Country：United States  

Presentation type：Public lecture, seminar, tutorial, course, or other speech  

Venue：C.S.I.C., Universitat Autonoma de Barcelona, Bellaterra   Country：Spain  

T. Kiss, Development of novel characterization techniques for basic understanding of current limiting mechanisms in coated conductors (Invited lecture), Invited lecture at Institut de Ciencia de Materials de Barcelona (ICMAB), Universitat Autonoma de Barcelona, 2006.12.

Presentation type：Oral presentation (general)  

Venue：Barcelona   Country：Spain  

T. Kiss, R&D on advanced conductors and power applications in Japanese superconductivity national projects (Invited talk), Cermae, Energy Challenges: Materials for energy production, storage, distribution and efficiency, 2006.12.

Presentation type：Oral presentation (general)  

Venue：熊本大学   Country：Japan