• Title/Summary/Keyword: 조성만

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Magnetic Properties of Mn and La-Mn Substituted Strontium Ferrite (Mn 및 La-Mn 치환 Sr 페라이트의 자기적 특성 변화)

  • 장세동;김종오;김종희
    • Journal of the Korean Magnetics Society
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    • v.11 no.6
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    • pp.267-271
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    • 2001
  • These experiments were carried out to examine the effects of elemental substitution of Mn and La-Mn on Sr-ferrite. The calcined properties for the Mn and La-Mn substitution were examined, and the sintered magnetic properties were compared with the stoichiometric condition. The magnetic properties of calcined SrM and (La-Mn)$_{0.3}$-SrM composition were as follows, respectively; M$_{s}$ : 61.06 emu/g, $_{i}$H$_{c}$ : 4.45 kOe and M$_{s}$ : 61.06 emu/g, $_{i}$H$_{c}$ : 4.46 kOe. Also, the sintered ferrite magnets of Mn$_{0.3}$-SrM and [(La-Mn)$_{0.3}$-SrM exhibited a similar properties to the stoichiometric composition but the coercivity of (La-Mn)$_{x}$-SrM was decreased rapidly with x=0.5.

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Comparision of Chemical Compositions between Cultured and Wild Fishes (1) Comparision between Cultured and Wild Eel Lipids (양식 및 천연산 어류의 화학성분에 관한 연구 1) 양식 및 천연산 뱀장어의 지질성분)

  • KIM Kyong-Sam;OK Kwans-Soo;LEE Eung-Ho
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.17 no.6
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    • pp.506-510
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    • 1984
  • The muscle lipids of cultured and wild eel, Anguilla japonica, were analysed by gas chromatography for fatty acid compositions of total lipid(TL), neutral lipid(NL), phospholipid(PL) and glycolipid(GL). And high performance liquid chromatography(HPLC) patterns of NL were analysed by HPLC. The lipid contents of dorsal muscle of cultured fish are slightly lower than that of wild fish. The contents of TL, NL and PL of wild fish were similar to those of cultured fish, while GL content of wild fish was higher than that of cultured one. In the fatty acid compositions of TL, NL and PL, percentages of $C_{16:0},\;C_{18:1}\;and\;C_{22:6}$ in cultured fish are higher than these in wild one, while percentage of $C_{16:1}$ is lower. Elution patterns in HPLC of NL of wild and cultured eel were slightly different.

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Effect of Vinyl Mulching on Growth of Various Sizes of Mulberry Saplings in a Dense Planting (밀식 뽕밭 조성시의 묘목규격별 비닐 피복효과)

  • 김호낙;박광준
    • Journal of Sericultural and Entomological Science
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    • v.24 no.1
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    • pp.19-24
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    • 1982
  • This experiment was carried out to develope a new planting system from the economical point of view, using the various sizes of mulberry saplings ranged from 3mm to 7mm (3, 4, 5 and 7mm) in diameter of branches. They were planted densely (2,285 trees/10a) in vinyl film-and non-mulching system. The results are summarized as follows. 1. There are no differences in growth and yield of the planting year between 6mm and 7mm saplings. 2. The vinyl mulching affords an abundant growth of the saplings due to retaining of soil temperature and moisture. The dense planting with vinyl film mulching gave rise to 26% and 7% increase of leaf yield, using the saplings sized of 7mm and 5mm, respectively. 3. On the other hand, it was evident that the use of 6mm saplings in non-mulching and 5mm ones in mulching redused possibly the sapling cost. It was also noteworthy an additional profit took places in the yield increase, the cost reduction of saplings and weeding by using the 7mm and 5mm saplings in mulching system. It amounted to the increase of ₩33,800 and ₩24,520, respectively over the use of 7mm saplings in non-mulching system.

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Analyses of Mineral Composition of Geochang Granitic Rocks for Stone Specification (거창화강석 품질기준 설정을 위한 광물조성 분석)

  • Choi, Jin-Beom;Jwa, Yong-Joo;Kim, Keon-Ki;Hwang, Gil-Chan
    • Journal of the Mineralogical Society of Korea
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    • v.19 no.4 s.50
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    • pp.363-381
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    • 2006
  • Mineral compositions of granitic rocks from Geochang, Pocheon, Iksan, and China were obtained by the modal analysis, CIPW norm calculations, and Rietveld quantitative analysis for stone specification of the Geochang granitic rocks. The Geochang granitic rocks show grey to dark in color and medium grained porphyritic texture. They mainly consist of quartz, plagioclase, alkali feldspar, and biotite. Among three different method for determining the mineral compositions of granitic rocks, normative compositions using X-ray fluorescence data are not appropriate for representing real mineral composition. Rietveld quantitative analysis using X-ray powder diffraction data is proved better method to determine exact mineral compositions than modal analysis using microscopic observation. Q-A-P diagram shows that the Geochang granitic rocks are typical granodiorite, whereas the granitic rocks of Pocheon, Iksan, and China are monzogranite, monzogranite to granodiorite, and granodiorite, respectively. Compared to China ones, the Geochang granitic rocks are nearly close to each other in mineral composition.

Effects of Sm:Ba:Cu Composition Ratio on the Superconducting Properties of SmBCO Coated Conductor Prepared by using a Composition Gradient Method (SmBCO 초전도 선재 특성에 대한 Sm:Ba:Cu 조성비의 영향)

  • Kim, H.S.;Oh, S.S.;Jang, S.H.;Min, C.H.;Ha, H.S.;Ha, D.W.;Ko, R.K.;Youm, D.J.;Moon, S.H.;Chung, K.C.
    • Progress in Superconductivity
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    • v.13 no.1
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    • pp.7-11
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    • 2011
  • The effects of Sm:Ba:Cu composition ratio in SmBCO coated conductor on their superconducting properties were investigated. The SmBCO coated conductors were fabricated by reactive co-evaporation method using EDDC(Evaporation using Drum in Dual Chamber) system. In this system, we could obtain various samples with different composition ratios in a batch by the technique providing composition gradient at deposition zone. From the specimens prepared by EDDC system, we found that composition ratio is uniform parallel to the drum axis, but gradient along the circumferential direction of the drum. We installed a shield having parallelogram open area between the deposition chamber and the evaporation chamber in EDDC system, and attached a 30 cm long template, which is parallel to drum axis, onto the drum surface. In this configuration, we could obtain SmBCO coated conductors having a gradient composition along the length of template. We measured the composition ratios and surface morphologies with periodic interval by SEM and EDAX, and confirmed the profile of composition ratio. We also measured critical current using non-contact Hall probe critical current measurement system and thereby could plot composition ratio vs. critical current. The maximum critical current was obtained, and the surface morphology with the shape of roof tile was observed at the corresponding composition ratio of Sm:Ba:Cu = 1.01:1.99:4.87. It was also found that composition ratio had an effect on not only critical current but also surface morphology.