著者

大塚 泰一郎

出版者

CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

雑誌

低温工学 (ISSN:03892441)

巻号頁・発行日

vol.34, no.4, pp.134-143, 1999-04-25 (Released:2010-02-26)

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The understanding of superconductivity has progressed in four stages. During the first period following the discovery of disappearance of electrical resistivity of mercury by Kamerlingh Onnes, attempts were made to understand superconductivity based only on zero resistance. The second period was initiated by the discovery of the Meissner effect. Based on new knowledge of the magnetic property of zero resistivity, phenomological theories were developed and new aspects of superconductivity were uncovered, culminating in the establishment of the BCS theory. The rediscovery of a second type of superconductivity together with flux quantization initiated the third period where fluxons play an active role. The fourth period, which is still in progress, was initiated by the discovery of oxides with dramatically high critical temperatures. All these activities were initiated by Kamerlingh Onnes' brilliant insight leading to the discovery of superconductivity.

著者

力石 浩孝

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.53, no.3, pp.122-129, 2018-05-20 (Released:2018-07-14)

参考文献数

6

---

The Large Helical Device (LHD) is a fusion plasma experimental device operating at the National Institute for Fusion Science. The LHD uses superconducting coils to generate a magnetic field for plasma confinement, and each coil is excited by a large-scale DC power supply. This paper introduces the DC power system and its design concept.

著者

冨中 利治

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.4, pp.192-201, 2014-04-25 (Released:2014-05-20)

参考文献数

19

被引用文献数

1 1

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The analytical formulae of the magnetic field, the vector potential and the inductances of long helical conductors with an arbitrary pitch are given as a unified scheme from a helical solenoid to a straight conductor. It is also shown that the obtained expressions are consistent with the well-known expressions for a closely wound helical solenoid and a straight conductor in both limits of the infinitesimal and infinite twist pitches, respectively. In addition, the right-handed and left-handed long helical conductors are clearly treated for this unified scheme.

著者

秋山 庸子 野村 直希 三島 史人 西嶋 茂宏

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.55, no.3, pp.172-178, 2020-05-20 (Released:2020-06-04)

参考文献数

16

被引用文献数

3

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An investigation as to whether or not superconducting high-gradient magnetic separation is capable of reducing the volume of cesium in contaminated soil is reviewed. This unique physical method can selectively remove paramagnetic 2:1-type clay minerals that strongly trap cesium inside the interlaminar site from soil suspensions. However, there are technical issues, such as wide particle size distribution and particle aggregation. To solve these problems, advanced pretreatments of advanced classification and alkaline dispersion treatments were performed, and the radioactivity concentration reduction rate was successfully increased. Based on the results, issues for practical application were discussed.

著者

本島 修

出版者

CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

雑誌

低温工学 (ISSN:03892441)

巻号頁・発行日

vol.32, no.11, pp.540-547, 1997-11-25 (Released:2010-02-26)

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The Large Helical Device (LHD) is a heliotron-type toroidal fusion experimental device which will provide useful and reliable datasets for high-temperature helical plasmas with an equivalent Q value of 0.1 to 0.35. One of the crucial tasks of LHD is to demonstrate steady-state operations by taking the advantage of its magnetic configuration with currentless plasmas as well as built-in divertors. In this respect, the coil systems are fully superconducting (SC); consisting of a pair of helical coils, three pairs of poloidal coils and nine bus lines. All the SC coils have been successfully fabricated with high accuracy and they are presently in the final stage of assembly in a cryostat vessel along with outside preparations of plasma heating devices, diagnostic equipment and control systems. The first plasma operation is scheduled for the end of March 1998. The technological development of SC magnets through this project played a key role in LHD, and will also be useful for constructing future fusion reactors.

著者

岡村 哲至 塩田 進 椛島 成治 真田 芳直

出版者

CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

雑誌

低温工学 (ISSN:03892441)

巻号頁・発行日

vol.20, no.6, pp.325-331, 1985-12-25 (Released:2010-02-26)

参考文献数

4

---

Design of a superconducting magnet to be coupled with a disk MHD generator in the closed cycle MHD experimental facility FUJI-1 is described. The superconducting magnet consists of two separated windings whose shape is of the circular Helmholtz type. A new structure between the windings has been proposed which supports magnetic force induced between the two windings and, at the same time, minimizes the heat leakage to the windings.

著者

三井 清人

出版者

CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

雑誌

低温工学 (ISSN:03892441)

巻号頁・発行日

vol.10, no.3, pp.104-109, 1975-07-15 (Released:2010-02-26)

参考文献数

9

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State of the art of the thermocouples and resistance thermometers for cryogenic temperatures is briefly reviewed: materials for cryogenic thermocouples and resistance thermometers, examples of their characteristics, related industrial standards and reference tables, recent development to be noticed, and comments on the practice of application, installation, calibration etc.

著者

中川 久司

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.50, no.6, pp.298-305, 2015-06-25 (Released:2015-07-07)

参考文献数

24

被引用文献数

1

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In order to ensure the reliability of research results obtained in very low temperature fields, it is important that very low temperature measurement is traceable to the internationally agreed the Provisional Low Temperature Scale of 2000 (PLTS 2000). The PLTS-2000 is defined by the relationship of 3He melting pressure pm to temperature T2000 in the range of 0.9 mK to 1 K and provides four intrinsic fixed points on the melting curve. In order to realize the PLTS-2000, it is necessary to cool 3He at melting pressure down to the possible lowest temperature using a nuclear demagnetization cryostat. This cryostat must be capable of working reliably and continuously over long periods of time during ultra-low temperature experiments. In this article, we give information about low-temperature techniques for realizing the PLTS-2000 based on our experiences of designing and constructing in-house ultra-low temperature apparatus.

著者

山田 穣

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.54, no.1, pp.37-42, 2019-01-20 (Released:2019-02-11)

参考文献数

7

著者

門奈 五兵

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.8, no.3, pp.118-119, 1973

著者

花田 卓爾

出版者

CRYOGENICS AND SUPERCONDUCTIVITY SOCIETY OF JAPAN

雑誌

低温工学 (ISSN:03892441)

巻号頁・発行日

vol.15, no.2, pp.128-140, 1980-05-25 (Released:2010-02-26)

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On September, 1978, Hydrogen Liquefaction Unit was established with a new plan to distribute customers by an industrial larger scale more than ever the way it had been applied. By this inovation caused in hydrogen distribution system, new chance was developed for the people who have not any knowladge and experience on the use of the liquid hydrogen.Accordingly, it is naturally requested to master the way of Liquid Hydrogen Safety Handring. This point will be guidance for people, operater and designer to easy handling the liquid hydrogen in the future.

著者

山本 明保 Jeremy WEISS Mark AINSLIE Anatolii POLYANSKII David LARBALESTIER Eric HELLSTROM

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.397-404, 2017-11-20 (Released:2017-12-08)

参考文献数

47

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This article reviews the recent development of bulk trapped field magnet made with iron-based superconductor (IBSC). A trapped field of over 1 T at 5 K and 0.5 T at 20 K has been measured between a stack of magnetized cylinders of bulk polycrystalline Ba0.6K0.4Fe2As2 superconductors 10 mm in diameter. Magneto-optical imaging revealed a trapped field distribution corresponding to uniform macroscopic current loops circulating through the sample. A standard numerical modelling technique using the measured Jc(B, T) characteristics of a small specimen reproduced the experimentally measured trapped fields well, again indicating the homogeneous current loops in the polycrystalline bulk. Given the untextured polycrystalline nature of the cylinders and their large irreversibility field, it is expected that larger IBSC bulks could trap much higher field.

著者

松下 照男 船木 和夫

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.1, pp.2-9, 2004 (Released:2007-02-16)

参考文献数

10

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This article focuses on Poynting’s vector which is defined by a vector product of electric and magnetic fields and plays an important role in considering a flow of electromagnetic energy between power supplies and various types of electromagnetic devices in electrical, electronical and information networks. Poynting’s vector is introduced from a law of energy conservation and its surface integral on an arbitrary domain is equal to the electromagnetic power inside it. This relation can be applied to any system in which there is an interest in the energy flow. Validity of the speculation that Poynting’s vector directly gives the energy flow is examined in various cases. It is pointed out that Poynting’s vector is not equal to the energy flow in some cases. Also discussed is the condition under which the equality holds.

著者

小林 慎一 中島 隆芳 山崎 浩平 佐藤 謙一

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.47, no.7, pp.422-429, 2012-07-25 (Released:2012-09-12)

参考文献数

27

被引用文献数

2 2

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Since the discovery of bismuth-based high-temperature superconductors in 1988 in Japan, much work has been done to develop superconducting wires and their applications. Applications include cables, motors, transformers and fault current limiters used at 77.3 K, high field magnets and motors used at 20 K and super-high field magnets and current leads used at 4.2 K. Some applications are already commercial products. This paper introduces the wire fabrication methods, wire characteristics and application apparatus.

著者

大平 勝秀

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.41, no.2, pp.61-72, 2006 (Released:2007-02-15)

参考文献数

29

被引用文献数

6 6

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Since liquid hydrogen has a high specific impulse as fuel for rockets, its technology has been developed in connection with space technology programs. On the other hand, with the recent advance of technologies such as fuel-cell vehicles and stationary fuel-cell systems, liquid hydrogen is also expected to be used as an efficient means of transporting and storing hydrogen used as a source for clean energy. Slush hydrogen is a two-phase solid-liquid cryogenic fluid consisting of solid hydrogen particles in liquid hydrogen. Compared with liquid hydrogen, the density and cryogenic heat capacity of slush hydrogen with a solid fraction of 50% increase by 16% and 18%, respectively. Various applications of slush hydrogen are anticipated such as fuel for reusable space shuttles and fuel cells, and as a more efficient means of transporting and storing liquid hydrogen. This paper describes the applications and technology developments of liquid and slush hydrogen.

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 4

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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

春山 富義 吉崎 亮造

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.17, no.3, pp.179-180, 1982-06-25 (Released:2010-02-26)

参考文献数

2

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

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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

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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.