• Title/Summary/Keyword: Differential scanning calorimetry

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Effect of annealing treatment on gelatinization of upland and lowland waxy brown rice starches (아닐링 처리가 밭벼와 논벼 찹쌀 전분의 호화에 미치는 영향)

  • Kim, Sung-Kon
    • Applied Biological Chemistry
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    • v.34 no.2
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    • pp.187-189
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    • 1991
  • Gelatinization temperatures of upland and lowland waxy brown rice starches annealed at $25^{\circ}C$ and $60^{\circ}C$ for 24hr were investigated with differential scanning calorimetry No annealing effect was observed at low temperature. The upland rice starch showed narrower range of gelatinization temperature upon annealing treatment at $60\circ}C$ compared with the lowland rice starch. The enthalpy of gelatinization was not changed in case of the upland rice starch but was increased in case of the lowland one upon annealing.

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Effects of Crystal Forms on Dissolution of Cephradin (세프라딘의 용출에 미치는 결정형의 영향)

  • Sohn, Young-Taek;Kim, Ji-Seon
    • Journal of Pharmaceutical Investigation
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    • v.28 no.2
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    • pp.115-119
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    • 1998
  • Five polymorphic modifications of Cephradin were prepared by recrystallization from organic solvents. The isolated crystal forms were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and X-ray crystallography powder diffractometry. Modificaition 1 was the most stable form and decomposed at $201.3^{\circ}C$. Modification 3 and 4 were metastable. The dissolution of modification 3 and 4 was faster than that of marketed form.

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Crystal Form of Cefuroxime axetil (세푸록심 악세틸의 결정형)

  • Kim, Bo-Yeon;Sohn, Young-Taek
    • Journal of Pharmaceutical Investigation
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    • v.37 no.1
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    • pp.23-26
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    • 2007
  • Two crystal forms of cefuroxime axetil were obtained by the recrystallization from different organic solvents and characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRD). It was confirmed that two crystal forms are identical. The dissolution patterns of these two forms were also checked in 0.07 N HCl at $37{\pm}0.5^{\circ}C$, 100 rpm for 180 minutes. The transformation during storage was also studied.

Reversible Melting Behaviors of Polyesters and Copolyetheresters studied by MDSC (MDSC를 이용한 폴리에스테르와 코폴리에테르에스테르의 가역적 융해거동 분석)

  • Kim, Hae-Young;Baik, Doo-Hyun
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.239-242
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    • 2001
  • Melting and crystallization are not reversible because supercooling is always needed for crystal growth. But, recently reversible melting and crystallization phenomena in semi-crystalline polymers, based on modulated differential scanning calorimetry(MDSC) with quasi-isothermal experiment mode were observed in the melting range and continuously proved by others. (omitted)

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폴리프로필렌의 친수화 개질 -Polypropylene-poly(vinyl alcohol-co-ethylene) 블렌드의 특성-

  • 임상규;손태원
    • Proceedings of the Korean Fiber Society Conference
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    • 1996.04a
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    • pp.64-68
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    • 1996
  • PP-EVOH(poly(vinyl alchol-co-ethylene)) blends were prepared by the mixing of polypropylene and poly(vinyl alcohol-co-ethylene) containing 38mol% of ethylene units (EVOH38) at melt state above PP melting temperature. The materials were characterized by using dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and contact angle measurement to detemine the glass transition, meltin, decomposition temperatures, and wettability respectively. From the results, PP-EVOH(poly(vinyl alcohol-co-ethylene)) blends exgibits partial miscibility.

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MULTI-RUN EFFECTS ON THE SOLID FUEL RAMJET COMBUSTION

  • Tae-Ho Lee
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1995.11a
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    • pp.3-8
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    • 1995
  • An experimental investigation was conducted in order to figure out the multiple fire effects on the combustion efficiency and fuel properties of the solid fuel ramjet. Pure HTPB and metallized $B_4$C/HTPB fuel were studied. Fuel property effects were analyzed by using differential scanning calorimetry, The thermal or mechanical properties of the fuel grain were not affected and the combustion efficiency was a little increased.

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Synthesis of Poly(enaryloxynitriles) Containing Schiff Bases and Their Thermal Properties

  • 김상곤;한양규;공명선
    • Bulletin of the Korean Chemical Society
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    • v.16 no.4
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    • pp.326-331
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    • 1995
  • Poly(enaryloxynitriles) containing Schiff bases were prepared from p-bis(1-chloro-2,2-dicyanovinyl)benzene (2) and various aromatic diols having Schiff base moiety by interfacial polymerization. The chemical structure of the polymers was confirmed through synthesis of their corresponding model compounds. All the polymers were soluble in polar aprotic solvents and their brittle films were cast from DMF solution. They showed a large exotherm around 340 ℃ attributable to the chemical change of dicyanovinyl group. Especially, curing of azomethine group was observed to occur at 390 ℃ by differential scanning calorimetry. According to the thermogravimetric analyses, they exhibited excellent thermal stability with 60-90% residual weight at 500 ℃ in nitrogen.

A Study on the Effects of Brassica oleracea L. Fractions on the Membrane Fluidity of the Liposomal Phospholipid Membranes

  • Park, Yun-Ja;Bae, Song-Ja
    • Proceedings of the PSK Conference
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    • 2003.04a
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    • pp.221.1-221.1
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    • 2003
  • This research was designed to investigate the effects of Bassica oleracea L. (BO) fractions on the membrane fluidity of the liposomal phospholipid membranes. The sample BO was extracted and fractionated to six different types. methanol(BOM), hexane(BOMH). ethylether(BOMEE), etylacetate(BOMEA), butanol(BOMB) and aqueous(BOMA) fractions. The fluidity of dipalmitoylphosphatidylcholine(DPPC) liposomal membranes incorporated with BO fraction was measured by means of high-sensitivity differential scanning calorimetry(DSC). (omitted)

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