• Title/Summary/Keyword: applied research

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The effect of local heating on superconductivities in internal tin Processed $Nb_{3}Sn$ wires (내부 확산법에 의한 $Nb_{3}Sn$ 초전도 선재에서 부분 가열이 초전도 특성에 미치는 영향)

  • Ha, Dong-Woo;Oh, Sang-Soo;Ha, Hong-Soo;Lee, Nam-Jin;Kwon, Young-Kil;Ryu, Kang-Sik
    • Proceedings of the KIEE Conference
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    • 1999.11d
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    • pp.876-878
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    • 1999
  • Internal tin processed Nb3Sn wires with different diameter were locally heated before reaction heat treatment. Local heating at the intermediate state of drawing process decreased the superconducting properties and workability. When the local heating temperatures were higher than melting point of Sn, non-Cu Jc's decreased significantly.

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Identification of insecticidal compounds from Streptomyces sp. no. 46 (Streptomyces sp.no. 46이 생산하는 살충성 물질의 구조 동정)

  • Oh, Sei-Ryang;Lee, Hyeong-Kyu;Koo, Bon-Tak;Choi, Soo-Keun;Park, Sang-Gu;Shin, Byung-Sik;Park, Seung-Hwan;Kim, Jeong-Il
    • Applied Biological Chemistry
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    • v.37 no.2
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    • pp.110-114
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    • 1994
  • In searching for new insecticidal compounds from soil microorganisms, strains of streptomyces species showed insecticidal activities on Musca domestica and Bombyx mori were selected. Compounds I-IV, which were isolated from the metabolites of no. 46 strain, were identified as piericidin $C_1$, $C_2$, $C_3$ and $D_1$, respectively by UV and NMR data analyses.

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Design of 16 Tesla Superconducting Magnet (16 Tesla급 초전도 마그네트의 설계)

  • Kwon, Young-Kil;Cho, Jeon-Wook;Lee, Eon-Yong;Jin, Hong-Bum;Ha, Dong-Woo;Oh, Bong-Hwan;Ryu, Kyung-Woo;Oh, Sang-Soo;Ryu, Kang-Sik
    • Proceedings of the KIEE Conference
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    • 1995.07a
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    • pp.141-143
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    • 1995
  • The design of a 16 tesla/ 45mm bore superconducting magnet is presented. The system consists of an 8.2 tesla(at 4.2K) outer NbTi coil with a bore I.D. of 261mm, a winding O.D. of 453mm and the length of 430mm which is connected in series with a 5.6 tesla(at 4.2K) middle and a 4.7 tesla(at 4.2K) inner insert coil constructed of multifilamentary $Nb_{3}Sn$. The middle and inner insert coil will be reacted after winding. Also, epoxy impregnation will be accomplished at $Nb_{3}Sn$ coils using a low viscosity crack resistant epoxy which is forced into the coil with a series of vacuum and over atmosphere pressure cycle.

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The Study on the Superconducting MRI Magnet of 68 cm in Room Temperature Bore (68 cm 상온 보아를 갖는 MRI용 초전도마그네트에 관한 연구)

  • Jin, H.B.;Oh, B.H.;Cho, J.W.;Oh, S.S.;Kwon, Y.K.;Ha, D.W.;Lee, E.Y.;Kim, H.J.;Kim, O.K.;Choi, B.J.;Ryu, K.S.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.11
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    • pp.142-146
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    • 1996
  • In this paper, we present the main research results on the 2 Tesla class - superconducting MRI magnet which we have developed. Multi section type superconducting MRI main coil and various superconducting shims were designed and fabricated for obtaining the high field homogeneity, which is requested in the MR imaging. After assembling the magnet with room temperature bore cryostat field homogenity has been measured and analyzed by NMR field mapping system. According to this, field homogeneity of 22 ppm / 30 cm dsv was confirmed.

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The effect of mechanical working on processing the Bi-2223/Ag tapes using PIT method

  • Oh, S.S.;Ha, D.W.;Kim, S.C.;Bae, S.W.;Kwon, Y.K.;Ryu, K.S.;Ha, H.S.
    • 한국초전도학회:학술대회논문집
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    • v.10
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    • pp.276-279
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    • 2000
  • When high temperature superconducting tapes is fabricated using the PIT (Powder In Tube) method, the length of HTS tapes is increased more than 500 ${\sim}$ 1,000 times of initial powder packed billet. On mechanical processing, heterogeneous properties between the ceramic superconducting core and Ag/Ag alloy sheath occur the non-uniformity deformation as like sausaging that deteriorate the critical current properties of HTS tapes. In this study, we investigated the workability of Bi-2223/Ag/Ag alloy sheath tapes fabricated by the PIT method involving a number of different mechanical processes, multi drawing and rolling. In order to obtain the high critical current density and high uniformity of Bi-2223/Ag sheath tapes, the influences of powder packing density, drawing die angle and rolling parameters were studied. We found that the roll diameter is an important variable in the rolling process, as critical current of tapes rolled using 250 mm rolls was higher than that using 150 mm rolls.

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A Study on Joint Characteristics for High Tc Superconducting Coils (고온초전도 코일 제작을 위한 겁합특성 연구)

  • Sohn, M.H.;Kim, S.W.;Baik, S.K.;Jo, Y.S.;Seo, M.G.;Lee, E.Y.;Kwon, Y.K.
    • Proceedings of the KIEE Conference
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    • 2002.07b
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    • pp.741-743
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    • 2002
  • Some different types of joining between two parallel high Tc superconducting tapes were prepared and I-V characteristic curves were obtained at the atmosphere of liquid nitrogen. Resistances in joint parts were estimated from I-V curves. We selected the best jointing method among these methods and its resistance were obtained at 28K. The availability of this joint method for fabricating HTS field coils is discussed.

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