Teion Kogaku (journal of The Cryogenic Society of Japan)最新文献_第7页

3d遷移金属置換Bi(Pb)2212単結晶の磁束ピンニング特性 3d过渡金属置换Bi(Pb)2212单晶体的磁通引针特性

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2004-04-25 DOI: 10.2221/JCSJ.39.155

雅直重森, 智史内田, 滋堀井, 淳一下山, 光二岸尾

{"title":"3d遷移金属置換Bi(Pb)2212単結晶の磁束ピンニング特性","authors":"雅直重森, 智史内田, 滋堀井, 淳一下山, 光二岸尾","doi":"10.2221/JCSJ.39.155","DOIUrl":"https://doi.org/10.2221/JCSJ.39.155","url":null,"abstract":"A large amount of lead doping to Bi2212 superconductors is effective in decreasing their high electromagnetic anisotropy and introduces effective pinning sites, such as lamella structure interfaces due to compositional fluctuation of lead ions, resulting in greatly enhanced flux pinning properties up to high temperatures. Particularly in the high-Tc superconducting materials with lowered anisotropy, further improvement of critical current properties can be expected by doping a small amount of impurity elements, which generate locally weak superconducting regions. Based on this background, we have attempted to enhance flux pinning strength of Bi(Pb)2212 single crystals by 3d metal doping in the present study. Crystal boules with starting compositions of Bi1.6Pb0.6Sr1.8Ca(Cu1-xMx)2Oy (M = Fe, Co, Ni : x = 0, 0.001, 0.002, 0.005, 0.02) were grown by the floating zone method. Tc's of the single crystals annealed to be the carrier overdoped state were dramatically decreased with an increase of metal doping levels. Critical current performance of the 3d metal-doped Bi(Pb)2212 crystals was quite poor at high temperatures near Tc, The crystal with x= 0.001, 0.002, 0.005, however, showed improved Jc properties accompanied by larger second peak effects in their magnetization hysteresis loops when compared with the 3d metal free Bi(Pb)2212 crystal below 50 K. On the other hand, magneto-optical measurements revealed that anisotropy in the in-plane Jc properties (Jca > Jcb ) was systematically suppressed with an increase of the doping level x. These results suggested that a very small amount of 3d metal doping is an essentially effective method to enhance pinning strength of Bi-based superconductors due to their generation of point-defect-like pinning centers. 3d doping, however, does decrease the pinning strength at the lamella structure interfaces.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2004-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131735075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

特集「高温超電導電流リード」によせて特集《高温超导电流导线》

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2004-03-25 DOI: 10.2221/JCSJ.39.72

通隆小野

引用次数: 0

電磁気学こぼれ話—超伝導応用のための電磁気学の問題第2話— 电磁学花絮——超导应用的电磁学问题第二集——

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2004-01-25 DOI: 10.2221/JCSJ.39.2

照男松下, 和夫船木

引用次数: 0

Self-field Loss in AC Transport Current Loss of MgB_2 Superconducting Composites MgB_2超导复合材料交流输运电流损耗中的自场损耗

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-11-25 DOI: 10.2221/JCSJ.38.615

Shinpei Nakagiri, M. Iino, S. Murase, N. Nanato, H. Kumakura, A. Matsumoto

引用次数: 4

Transport Properties of PIT-processed MgB_2 Wire and Coil pit处理MgB_2导线及线圈的输运特性

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-11-25 DOI: 10.2221/JCSJ.38.623

Kazuhide Tanaka, M. Okada, H. Kumakura, H. Kitaguchi

引用次数: 1

Treeing Characteristic of EPR for Solid Insulated Superconducting Cable 固体绝缘超导电缆EPR的树形特性

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-10-25 DOI: 10.2221/JCSJ.38.554

A. Minoda, Y. Mizuno, Y. Muramoto, Naohiro Nozumi, M. Nagao, M. Kosaki

引用次数: 0

Biological Immunoassay with a SQUID Magnetometer 用SQUID磁强计进行生物免疫测定

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-09-25 DOI: 10.2221/jcsj.38.469

K. Enpuku

引用次数: 2

Development of a Nb_3AI Conductor to be Applied to a Fusion Reactor and Its Application to a Large Superconducting Coil 核聚变用Nb_3AI导体的研制及其在大型超导线圈中的应用

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-08-25 DOI: 10.2221/JCSJ.38.391

N. Koizumi, K. Okuno, H. Nakajima, T. Ando, H. Tsuji

{"title":"Development of a Nb_3AI Conductor to be Applied to a Fusion Reactor and Its Application to a Large Superconducting Coil","authors":"N. Koizumi, K. Okuno, H. Nakajima, T. Ando, H. Tsuji","doi":"10.2221/JCSJ.38.391","DOIUrl":"https://doi.org/10.2221/JCSJ.38.391","url":null,"abstract":"The Japan Atomic Energy Research Institute has been involved in developing Nb3Al conductors since the middle of 1980s based on the consideration that Nb3Al conductors are capable of producing a higher magnetic field than Nb3Sn conductors owing to the extremely high critical current density in high magnetic fields. At the beginning of the development work, a fabrication technique for Nb3Al strands using a Jelly-roll process was established. This process requires heat treatment at 750°C for 50 h instead of a temperature of more than 1,800°C as required by the conventional method. Using this technique, about 1 ton of strands was produced and a 150-m Nb3Al cable-in-conduit conductor was fabricated. For the next step, to demonstrate the applicability of the Nb3Al conductor to a large coil, a coil 1.5-m in diameter, called the Nb3Al Insert, was manufactured. A react-and-wind method was tried for the production process as it simplifies the fabrication of large coils such as an ITER-TF coil. Performance tests of the Nb3Al Insert were conducted in 2002. The Nb3Al Insert could be charged to the designed point of 13 T and 46 kA without showing any instability. Thus, the world's first large superconducting coil using a Nb3Al conductor was successfully developed, thus indicating the possibility of producing fusion magnets that can operate in higher magnetic fields than those used with Nb3Sn conductors.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"56 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122654362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

ケーブル・イン・コンジット導体の交流損失特性电缆连接导体的交流损耗特性

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-08-25 DOI: 10.2221/JCSJ.38.410

邦浩松井, 良和高橋, 徳潔小泉, 高明礒野, 一弥濱田, 嘉彦布谷, CSモデル・コイル実験グループ

{"title":"ケーブル・イン・コンジット導体の交流損失特性","authors":"邦浩松井, 良和高橋, 徳潔小泉, 高明礒野, 一弥濱田, 嘉彦布谷, CSモデル・コイル実験グループ","doi":"10.2221/JCSJ.38.410","DOIUrl":"https://doi.org/10.2221/JCSJ.38.410","url":null,"abstract":"The ITER Central Solenoid (CS) model coil, CS Insert and Nb3Al Insert were developed and tested from 2000 to 2002. The AC loss performances of these coils were investigated in various experiments. In addition, the AC losses of the CS and Nb3Al Insert conductors were measured using short CS and Nb3Al Insert conductors before the coil tests. The coupling time constants of these conductors were estimated to be 30 and 120 ms, respectively. On the other hand, the test results of the CS and Nb3Al Inserts show that the coupling currents induced in these conductors had multiple decay time constants. In fact, the existence of the coupling currents with long decay time constants, the order of which was in the thousands of seconds, was directly observed with hall sensors and voltage taps. Moreover, the AC loss test results show that electromagnetic force decreases coupling losses with exponential decay constants. This is because the weak sinter among the strands, which originated during heat treatment, was broken due to the electromagnetic force, and then the contact resistance among strands increased. It was found that this exponential decay constant was the function of a gap (i.e., a mechanical property of the cable) created between the cable and conduit due to electromagnetic force. The gap can be estimated by pressure drop, measured under the electromagnetic force. The pressure drop can easily be measured at an initial trial charge, and then it is possible to estimate the exponential decay constant before normal coil operation. Accordingly, it is possible to predict promptly how many times the trial operations are necessary to decrease the coupling losses to the designed value by measuring the coupling losses and the pressure drop during the initial coil operation trial.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127113868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Modeling of a Distributed Constant Electric Circuit considering Contact Resistance and Coupling Loss Analyses for Cable Twisted at Multiple Stages 考虑接触电阻和多段绞合电缆耦合损耗的分布式常数电路建模

Teion Kogaku (journal of The Cryogenic Society of Japan) Pub Date : 2003-07-25 DOI: 10.2221/jcsj.38.348

K. Seo, K. Fukuhara, M. Hasegawa

{"title":"Modeling of a Distributed Constant Electric Circuit considering Contact Resistance and Coupling Loss Analyses for Cable Twisted at Multiple Stages","authors":"K. Seo, K. Fukuhara, M. Hasegawa","doi":"10.2221/jcsj.38.348","DOIUrl":"https://doi.org/10.2221/jcsj.38.348","url":null,"abstract":"AC losses in multi-strand superconducting cables, utilized in large-scale applications such as fusion machines, are governed by the contact resistance between strands. Especially, in cable twisted at multiple-stages, a variety of magnetic field diffusion time constants exist and these correspond to the quantity of inter-strand coupling loss in each cabling stage. The rate of magnetic field change is less than several T/s in an average fusion machine. Under this condition, the magnetic field penetrates the cable well and the coupling current circuit with the larger time constant causes larger AC loss. Here, the time constant is equal to the leakage inductance divided by the resistance along the coupling current loop. Therefore, by evaluating the coupling current in the larger loop, which consists of a higher twisting stage (e.g., usually the final cabling stage), the loss in the entire cable can be determined. The leakage inductance between sub-cables can be estimated by considering the electrical centers. On the other hand, inter-sub-cable contact resistance was not previously evaluated due to its complexity. In this study, we established an inter-sub-cable contact resistance model that allows the AC loss in cable with multiple twisting stages to be evaluated numerically. The modeling of contact resistance between sub-cables is discussed in detail.","PeriodicalId":285677,"journal":{"name":"Teion Kogaku (journal of The Cryogenic Society of Japan)","volume":"141 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2003-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115139669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0