• 제목/요약/키워드: Calorimetry

검색결과 1,162건 처리시간 0.031초

Cholesteryl S -Alkoxybenzene Thiocarbonates의 합성과 액정 성질에 관한 연구 (Synthesis and Mesomorphic Behavior of Cholesteryl S-Alkoxybenzene Thiocarbonates.)

  • 전영재
    • 한국재료학회지
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    • 제2권6호
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    • pp.398-407
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    • 1992
  • Cholesteryl S-alkoxybenzene thiocarbonates를 합성하여 그들의 상전이 온도를 조사하였다. 이 계열 화합물들은 모두 호변성 cholesteric 액정상을 나타낸다. 상전이 온도는 시차주사열분석기 (DSC)로 측정하였으며, 측정된 cholesteric-isotropic 상전이 온도는 alkoxy 사슬 길이 증가에 따라 감소한다.

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Synthesis and Characterization of Novel Fused Aromatic Semiconductors

  • Zhao, Qinghua;Park, Jong-Won;Kim, Yun-Hi;Kwon, Soon-Ki
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1193-1197
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    • 2006
  • The novel oligomers were synthesized by Grignard reaction, the suzuki coupling reaction, etc. The oligomers were characterized by Infrared (IR), Mass spectrometer (MS). Their thermal properties were investigated by differential scanning calorimetry (DSC) and Thermogravimetric analysis (TGA). The new oligomers showed high thermal stability above $300^{\circ}C$.

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

  • 김성곤
    • Applied Biological Chemistry
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    • 제34권2호
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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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세프라딘의 용출에 미치는 결정형의 영향 (Effects of Crystal Forms on Dissolution of Cephradin)

  • 손영택;김지선
    • Journal of Pharmaceutical Investigation
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    • 제28권2호
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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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세푸록심 악세틸의 결정형 (Crystal Form of Cefuroxime axetil)

  • 김보연;손영택
    • Journal of Pharmaceutical Investigation
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    • 제37권1호
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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.

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

  • Kim, Hae-Young;Baik, Doo-Hyun
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 2001년도 가을 학술발표회 논문집
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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
    • 한국섬유공학회:학술대회논문집
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    • 한국섬유공학회 1996년도 춘계학술발표회 논문집
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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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