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

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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

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

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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

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)

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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

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

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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 7

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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.

著者

高橋 勝國 斎藤 敏雄 柳島 淑隆 神谷 祥二 老固 潔一 岩田 章 増井 喜健

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.15, no.2, pp.97-110, 1980-05-25 (Released:2010-02-26)

参考文献数

18

被引用文献数

3

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This paper presents the results of a study on the pressure drop and the film boiling heat transfer for a two-phase flow of hydrogen in a horizontal tube.Experiments were made on two types of tube; two pieces of vacuum insulated straight tubes of 4m long, inside diameters of which are 18.4 and 23.9mm, respectively; Anuninsulated tube of 8m long with 90 degree bends at two locations, inside diameter of which is 12.3mm.Experimental conditions were as follows; Flow rate (l/min.); 5 to 50 Vapor quality; 0.01 to 0.90 Pressure (bar); 1.4 to 5.8 Conclusions obtained from the experiments are summarized below.1) The frictional pressure drop of two-phase flow of hydrogen for a straight tube is well related to a modified Lockhart-Martinelli (L-M) curve, that is, L-M pressure ratio parameter, φl multiplied by 0.8, for both adiabatic and diabatic conditions. More than 90% of data fell within the scatter band of ±20% from the modified L-M curve.The pressure drop for a bend was also correlated by using parameters analogically introduced from L-M parameters for a straight tube.2) As for the heat transfer by forced-convection film boiling, the following relationship was established based on the method proposed by Ellerbrock.(Nuf/Nufm)⋅Bo-0.4=9.46Xtt-0.131More than 90% of data obtained were in agreement with the the expression shown above with no more than ±20% error.In this study, it was known that the heat transfer for two-phase flow of nitrogen as well as hydrogen follow Ellerbrock's theory.