著者
神原 陽一
出版者
公益社団法人 低温工学・超電導学会 (旧 社団法人 低温工学協会)
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.52, no.6, pp.383-388, 2017-11-20 (Released:2017-12-08)
参考文献数
83

After obtaining my doctorate in engineering from Keio University, I spent five years as a researcher at the Tokyo Institute of Technology, Suzukakedai Campus in Yokohama. During that time, I made the first report on a material system called iron-based high-temperature superconductors (Fe-SCs). Research on Fe-SCs is still hot topic in condensed matter physics. Now, I am continuing my research mainly on the fabrication of superconducting wire using Fe-SCs, while being distracted by some traditional affairs as a member of the faculty. Research on Fe-SCs has encouraged young researchers towards the further discovery of novel layered superconductors. This article was prepared by updating the content of “A Private Story, Discovery of Iron-based High Tc Superconductors” previously published in the membership journal of the Physical Society of Japan (Nihon Butsuri Gakkaishi).
著者
山本 純也
出版者
公益社団法人 低温工学・超電導学会
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.11, no.5, pp.222-228, 1976-11-10 (Released:2010-02-26)
参考文献数
4

This article describes methods of measuring liquid helium quantity, preparing a transfer tube, experimental set up of a cryostat, precooling, and transfering liquid helium, The properties of liquid helium are also simply explained for beginners. Precooling by liquid nitrogen is strongly recommended for decreasing liquid helium consumption.
著者
富岡 章 能瀬 眞一 八木 裕治郎
出版者
CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.41, no.1, pp.28-35, 2006

We have developed the production technology for HTS magnets used in power transformers. Two subjects were mainly studied (i.e., high-voltage technologies and large current and low AC loss technologies) to establish the production method for a 66 kV / 6.9 kV 10 MVA-class HTS power transformer. In order to verify the validity of the elemental technologies, a single-phase 66 kV / 6.9 kV 2 MVA-class model HTS transformer was manufactured and tested. The test results indicate that the elemental technologies established can be used for the development of a 66 kV / 6.9 kV 10 MVA-class HTS power transformer.
著者
中島 良 佐藤 和雄 甲斐 美香 小林 良雄
出版者
公益社団法人 低温工学・超電導学会
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.27, no.2, pp.152-157, 1992-04-25 (Released:2010-02-26)
参考文献数
10

Resistance vs. temperature relations of 200 carbon resistors (Allen Bradley 100Ω, 1/8W), widely used for cryogenic temperature measurements, were investigated in the range between liquid helium temperature and 20K. Obtained data are statistically evaluated, and it is apparently shown that the difference of the carbon resistor's lot affects the resistance value at the cryogenic temperatures. Four empirical formulas for the resistance vs. temperature relation proposed by other researchers are evaluated. According to this result, the equation, logR+K/logR=A+B/T, proposed by Clement et al. has most precise fitting below 10K. The authors propose a new empirical equation by applying Clement's equation. It is found that the three undecided coefficients, A, B and K of the equation can be calculated from the resistance at 4.2K alone, thus enabling one-point calibration at liquid helium temperature. Resistance changes caused by ten times temperature cyclings from room temperature to liquid helium temperature are also measured. These are within -0.05-+0.02K, though measurments are slightly diverged by temperature cyclings.
著者
吉田 清
出版者
公益社団法人 低温工学・超電導学会 (旧 社団法人 低温工学協会)
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.44, no.8, pp.346-352, 2009 (Released:2009-10-15)
参考文献数
17
被引用文献数
1 1

The upgrading of the JT-60U to the JT-60SA has started in a joint effort by the Japanese government (JA) and European commission (EU) under the framework of the Broader Approach (BA) Agreement. The superconducting magnet system for the JT-60SA consists of 18 toroidal field (TF) coils, a central solenoid (CS) with four modules, and six equilibrium field (EF) coils. The TF case encloses the winding pack and is the main structural component of the magnet system. The CS consists of independent winding pack modules, which are hung from the top of the TF coils through its pre-load structure. The six EF coils are attached to the TF coil case through supports with flexible plates that allow radial displacement. The CS modules operate at high field and use a Nb3Sn superconductor. The TF coils and EF coils use NbTi superconductors. This paper describes the technical requirements, operational interface and detailed manufacturing design outline of the superconducting magnet system for the JT-60SA.
著者
中島 洋
出版者
CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.37, no.4, pp.148-156, 2002-04-25 (Released:2010-02-26)
参考文献数
11

The development of a superconducting Maglev system in Japan was started more than 30 years ago. Since 1997, the running tests have been successfully continued on the Yamanashi test line. A manned run in 1999 attained a speed of 552km/h, The Yamanashi test results proved a remarkable stability of the onboard superconducting magnet system, In these 30 years, we have encountered many difficult problems during this development. In this paper, the history of the Maglev development will be introduced with focus on these problems, especially in regard to the superconducting magnets and onboard refrigerators.
著者
三木 孝史 斉藤 一功 林 征治 梶川 弘 嶋田 雅生 小川 陸郎 川手 剛雄 池谷 大 木村 則幸 高畠 和男 西澤 節 杉浦 伸裕 鈴木 基文
出版者
CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.31, no.5, pp.258-266, 1996-05-25 (Released:2010-02-26)
参考文献数
14
被引用文献数
1 1

So far, the use of superconducting magnets has been limited to chemical analysis and medical inspection. To develop a new use, we have tried to apply common MRI devices as nondestructive sugar content detector of watermelon. To estimate the sugar content, a new technique using multiple regression analysis of two NMR relaxation times was developed. It was found that the coefficient of multiple regression at the center of the watermelon exceeded 0.9 and the standard error of prediction was around 0.5, and that the over-ripened part of flesh called ‘nieka’ in watermelon could be distinguished because its T2 was much longer than that of the oridinary part. An evaluation rate of sugar content could be below 6s per watermelon. It is concluded that multiple analysis of T1 and T2 on intact watermelon can be applied as a non-invasive, nondestructive indicator of sugar content.
著者
川島 健司 伊豫 彰 荻野 拓
出版者
公益社団法人 低温工学・超電導学会 (旧 社団法人 低温工学協会)
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.52, no.6, pp.389-396, 2017-11-20 (Released:2017-12-08)
参考文献数
46

We report discoveries and properties of new 112-type (Ca,Ln)FeAs2 (Ln = La ~ Gd) and 1144-type AeAFe4As4(Ae = Ca, Sr, Ba, Eu, A = K, Rb, Cs) Fe-based superconductor structures. (Ca,Ln)FeAs2 has a monoclinic system with a space group P21/m composed of two Ca(Pr) planes, Fe2As2 layers, and As2 zigzag chain layers. (Ca,Ln)FeAs2 shows superconductivity with a transition temperature (Tc) at 20 ~ 40 K. Although (Ca,Ln)FeAs2 has thick blocking layers, it has relatively high critical current density over 106 A/cm2 at 5 K (self-field). AeAFe4As4 has a tetragonal system with a space group, P4/mmm, Ae and A layers are inserted alternately between the Fe2As2 layers in the c-axis direction. AeAFe4As4 is a stoichiometric compound having Tc = 31 ~ 36 K, depending only on the combination of Ae and A. Both new superconductors are promising materials for application due to their characteristic properties.
著者
大塚 泰一郎
出版者
低温工学協会
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.35, no.12, pp.568-574, 2000-12-25
参考文献数
10
著者
田中 雅光 藤巻 朗 井上 弘士
出版者
公益社団法人 低温工学・超電導学会 (旧 社団法人 低温工学協会)
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.52, no.5, pp.323-331, 2017-09-20 (Released:2017-10-27)
参考文献数
50

The recent trend and perspectives for high-performance microprocessors based on superconductor single-fluxquantum (SFQ) logic families are described. The rapid single-flux-quantum (RSFQ) and its energy-efficient derivatives are promising as a next-generation digital circuit technology for very-large-scale integration in the post-Moore's era because of the capability of ultrahigh-frequency operation over 100 GHz and low energy consumption. Several ongoing research projects as well as results reported, including several demonstrations of SFQ-based microprocessors and their components, are reviewed.
著者
池田 博 土井 浩一郎 福田 洋一 野口 隆志 中嶋 俊哉 飯村 憲 渋谷 和雄
出版者
公益社団法人 低温工学・超電導学会 (旧 社団法人 低温工学協会)
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.39, no.8, pp.348-353, 2004 (Released:2008-03-10)
参考文献数
8
被引用文献数
3 3

From February 2003 to January 2004, a new superconducting gravimeter with a cryocooler was installed to replace the former device at the Syowa station in Antarctica. The new gravimeter has a high sensitivity of one nano-gal and is being used to survey the earth's core in the Global Geodynamics Project. A new type of diaphragm was confirmed to well isolate the vibration from the refrigerator cold-head and effectively prevent solid air contamination. A remote monitoring system from Japan is also going to be installed.
著者
東川 甲平 井上 昌睦 木須 隆暢
出版者
公益社団法人 低温工学・超電導学会 (旧 社団法人 低温工学協会)
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.49, no.9, pp.485-493, 2014-09-25 (Released:2014-10-24)
参考文献数
15

This article reviews a method for characterizing the local critical current density (Jc) distribution in superconducting tapes and wires based on scanning Hall-probe microscopy (SHPM). This method is very powerful for (1) finding the bottleneck that limits the global performance of a superconductor, (2) investigating the local inhomogeneity that may become the origin of local quench, especially in HTS applications, (3) establishing the processes for narrow and/or multifilamentary HTS conductors for reducing the magnetization in magnet applications and the AC losses in power applications. The principle and the functions of this technique are introduced by referring to characterization examples of REBCO coated conductors and an MgB2 wire.
著者
森 大吉郎
出版者
公益社団法人 低温工学・超電導学会
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.17, no.4, pp.215-221, 1982-08-30 (Released:2010-02-26)

Noticing the excellent performance of liquid hydrogen-liquid oxygen (LH2/LOX) propulsion system, the Institute of Space & Astronautical Science (ISAS) has started the preliminary study in 1971, and since 1975, full-scale development program of the engine, which has the capability of 7ton thrust in vacuum, has been undertaken.Various development tests of the engine components (thrust chamber, turbopump, gas-generator and turbine spinner etc.) have been conducted at the Noshiro Testing Center of ISAS.Integration tests of the stage, comprised of thrust chamber, turbopump, gas-generator and tank, have been carried out from September through December in 1981 with fairy good results.In the present paper, major features and characteristics of this 7ton engine are summarized.
著者
井上 廉
出版者
CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.30, no.8, pp.369-376, 1995

The hybrid magnet, which is a large system composed of an inner water-cooled magnet and an outer superconducting magnet, is well known to be the most suitable for generating steady high-magnetic fields. Thirty T-class hybrid magnets are being operated at several high-magnetic field laboratories, The world's highest steady field at present is 35.2T. Projects to enhance the steady fields up to 40-45T are progressing now at the National Research Institute for Metal, Japan, and the National High Magnetic Field Laboratory, USA. In particular, the NRIM project is just now nearing the final stage. In this article, I review in detail the hybrid magnet technology including those of superconducting magnet and water-cooled magnet, the present status of hybrid magnet systems in operation, and the developing projects at NRIM.

1 0 0 0 OA 超伝導入門

著者
大塚 泰一郎
出版者
公益社団法人 低温工学・超電導学会
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.35, no.6, pp.279-284, 2000-06-25 (Released:2010-02-26)
参考文献数
7

As described in the previous chapters, experiments following the introduction of the London theory revealed a few serious problems which could not be explained by the theory. Examples are transition to the normal state when the magnetic field is applied parallel to the surface of a superconducting film and the dependence of the penetration depth on the addition of impurities. The latter problem was resolved by Pippard through the introduction of the coherence length as described in the previous chapter. A serious problem which remained unresolved was the surface energy at the boundary of the superconducting and normal phases in the intermediate state of Type 1 superconductors. The stability of the intermediate state observed in experiments requires the boundary energy to be positive, which can not be explained by the London theory. In the next few chapters, the phenomological theory by Ginzburg and Landau, which not only resolved these problems but also led to the prediction of Type 2 superconductors, will be described.
著者
山田 豊 長谷部 次教 柳谷 知之 直原 和哲 石塚 正之 安原 征治 石原 守
出版者
公益社団法人 低温工学・超電導学会
雑誌
低温工学 (ISSN:03892441)
巻号頁・発行日
vol.28, no.2, pp.86-91, 1993-02-25 (Released:2010-02-26)
参考文献数
12
被引用文献数
3 4

Superconducting properties of Bi-Pb-Sr-Ca-Cu-O superconducting bulk fabricated by intermediate cold isostatic pressing (C. I. P.) process have been investigated, and heat leakage per a bulk lead pair from 77K to 4.2K has been evaluated. The critical current density of the tubular bulk, approximately inner diameter 10-30mm and 200mm long, was indicated more than 1, 000A/cm2 at 77K under self-magnetic field, and at 4.2K was indicated as about 2, 000A/cm2 under 15T. The reasons for improvement of Jc are the formation of high Tc single phase and highly aligned microstructure of the bulk. The heat leakage per a pair of the bulk leads from 77K to 4.2K has been measured to be 0.16W at DC 800A and considered to be less than one-tenth of that of 800A-class conventional gas-cooled current leads.