• 제목/요약/키워드: B powder

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$MgB_2/Fe$ 선재의 초전도성에 대한 열처리 조건과 Mg 분말의 영향 (Influence of Magnesium Powder and Heat Treatment on the Superconducting Properties of $MgB_2/Fe$ Wires)

  • ;김남규;김이정;전병혁;김찬중
    • Progress in Superconductivity
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    • 제9권1호
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    • pp.1-4
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    • 2007
  • The most common technique to fabricate $MgB_2$ superconducting wire is by powder-in-tube (PIT) technique. Therefore, the starting powder for the processing of $MgB_2$ superconductors is an important factor influencing the superconducting properties and performance of the conductors. In this study, the influence of magnesium precursor powders and annealing temperatures on the transition temperatures ($T_c$) and critical current densities ($J_c$) of $MgB_2/Fe$ wires was investigated. All the $MgB_2/Fe$ wires were fabricated by in situ PIT process. It was found that higher $J_c$ was obtained for $MgB_2$ wires with smaller particle size of magnesium precursor powders. The $J_c$ also increases with decreasing annealing temperatures.

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솔잎분말 첨가 양념 및 양념 돼지갈비의 저장중 품질특성 변화 (Quality Characteristics of Seasoned Sauce and Seasoned Pork Rib with added Pine Needle Powder during Storage)

  • 이지은;오명숙
    • 한국식생활문화학회지
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    • 제23권5호
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    • pp.629-638
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    • 2008
  • The principal objective of this study was to determine the quality characteristics of seasoned sauce and seasoned pork rib to which pine needle powder was added during storage. The pH value, color value, active bacterial cell count, lipid oxidation, shear force, and sensory evaluation of seasoned sauce and seasoned pork rib to which 0, 1, 2, 3 and 4% pine needle powder was added were measured during storage at $5^{\circ}C$. The storage periods for the seasoned sauce were 0, 1, 3, 5, 7, 14, 21 and 30 days, and the storage periods for the seasoned pork ribs were 0, 1, 3, 5, 7 days. We determined that the pH values of both seasoned sauce and seasoned pork rib decreased with increasing quantities of pine needle powder and longer storage periods. The lightness (L) and yellowness (b) of the seasoned sauce were increased and the redness (a) of that decreased with increasing pine needle powder contents and longer storage periods. The L, a, and b values of the seasoned pork rib decreased with increasing pine needle powder contents, whereas the L and b values of that were decreased and the a value increased with longer storage periods. The active bacterial cell count of the seasoned sauce was detected at between $10^2$ to $10^4$ CFU/mL over a storage period of 30 days, regardless of the addition of pine needle powder; additionally, the addition of 4% pine needle powder resulted in the lowest active bacterial cell count among the samples. The active bacterial cell count in the seasoned pork rib decreased with increasing additions of pine needle powder, and was increased during storage. The influence of pine needle powder contents on the active bacterial cell count of seasoned pork rib were minimal, and the active bacterial cell count of that was suppressed by the addition of only 1% pine needle powder. Lipid oxidation in the seasoned pork rib was suppressed by the addition of more than 2% pine needle powder. We noted no difference in the shear force of the seasoned pork rib to which pine needle powder was added. In our sensory evaluation, the intensity of color (greenish brown), flavor (herbal flavor) and taste (bitter & herbal taste) of the seasoned pork rib increased with increasing pine needle powder contents, whereas the texture of the seasoned pork rib evidenced no differences. The overall acceptability of the seasoned pork rib with 0, 1 and 2% added pine needle powder was higher than that of the seasoned pork rib with 3 and 4% added pine needle powder. Thus, the addition of 2% pine needle powder to seasoned pork rib sauce yielded appropriate results with regard to antibacterial, antioxidative, and sensory properties.

분쇄방법에 따른 고려홍삼분말의 품질특성 (Quality Characteristics of Korean Red Ginsneg Powder on Pulverizing Methods)

  • 서창훈;이종원;도재호;장규섭
    • Journal of Ginseng Research
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    • 제26권2호
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    • pp.79-84
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    • 2002
  • 홍삼 분쇄의 신 가공 기술로서 비충격(非衝擊)분쇄방식인 cell cracker의 공장 적용 가능성을 제시하고 홍삼분말의 품질고급화에 기초자료로 활용하고자 기존의 hammer mill(충격분쇄방식)과 cell cracker에 의한 분쇄방식으로 홍삼분말을 제조한 후 색도, 밀도 및 관능적 특성을 비교 조사한 결과를 요약하면 홍삼분말의 색도는 cell cracker로 분쇄한 홍삼분말의 경우 색의 밝기를 나타내는 L값은 68.15로 hammer mill로 분쇄한 홍삼분말 72.08 보다 낮았으나 a(적색도) 와 b(황색도)값은 각각 4.21과 5.73, 26.56과 28.36으로 높게 나타났다. 물 추출물의 색도는 시간이 경과함에 따라 두 가지 시료 모두 흡광도가 증가하였으며 전반적으로 hammer mill로 분쇄한 홍삼분말이 cell cracker로 분쇄한 홍삼분말 보다 흡광도가 높게 나타났다. 밀도는 분말의 유동성 특성을 나타내는 이완겉보기밀도, 충격겉보기밀도, 체적감소율은 hammer mill로 분쇄한 홍삼분말보다 cell cracker로 분쇄한 홍삼분말이 모두 높게 나타났다. 미Rm럼각은 쌓임각 보다 낮았으며 이 두 가지 모두 hammer mill로 분쇄한 홍삼분말 보다 cell cracker로 분쇄한 홍삼분말이 낮게 나타났다. 관능검사결과 촉감에 있어서는 두 시료간에 유의 차가 없는 것으로 나타났지만, 홍삼분말 제품의 품질 특성에 큰 영향을 미치는 색도는 cell cracker가 좋게 평가되었으며, 전체적인 선호도에 있어서도 좋게 나타났다. 이상의 연구결과를 종합해볼 때 홍삼분말의 품질 특성에 미치는 요소로서 분쇄방법이 중요한 인자로 작용하고 있음을 알 수 있었으며 홍삼분말의 제조에는 분쇄기 선정이 무엇보다 중요하며 특히 색깔 등 관능적 품질이 강조되는 홍삼분말 제품을 제조할 경우는 기존 충격식 분쇄보다 비충격식 분쇄시스템을 적용하는 것이 품질향상 효과가 클 것으로 생각된다.