• 한국식품영양과학회지
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• 제21권4호
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• pp.428-435
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• 1992

현미 전분의 고유점도는 일반계와 통일계 사이에 유의적인 차이가 없었다. 시차주사열량기에 의한 전분의 호화개시온도는 통일계보다 2$^{\circ}C$ 정도 높았고, 호화온도의 범위는 일반계가 통일계보다 유의적으로 컸으나 호화엔탈피는 유의적인 차이가 없었다. 호화에 필요한 수분함량과 아닐링 처리에 의한 호화성질은 서로 유의적인 차이를 보이지 않았다. 호화에 필요한 수분함량은 일반계의 경우 호화온도 범위와 부의 상관을, 통일계 경우에는 고유점도와 부의 상관을 보였다. 전분의 고유점도는 일반계와 통일계 모두 호화 엔탈피와 정의 상관을 보였다.

• Elastomers and Composites
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• 제54권4호
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• pp.271-278
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• 2019

Polyurethane elastomers (PUEs) were synthesized using trans-1,4-bis(isocyanatomethyl) cyclohexane (1,4-H₆XDI), poly(oxytetramethylene) glycol, 1,4-butanediol (BD), and 1,1,1-trimethylol propane (TMP). To control the molecular aggregation state and mechanical properties of these PUEs, hard segment contents of 20 and 30 wt% and BD/TMP ratios of 10/0 and 8/2 were chosen. Differential scanning calorimetry and small-angle X-ray scattering measurements revealed that the degree of microphase separation increased with an increase in both hard segment content and BD ratio. The Young's modulus and strain at break of the 1,4-H₆XDI-based PUE were 6-20 MPa and 5-15, respectively. Incorporation of 20% TMP as a cross-linking agent into BD increased the melting temperature of the hard segment chains, that is, heat resistance, and decreased the Young's modulus. This could be due to the low density of the physical cross-linking network and the dispersion of hard segment chains in the soft segment matrix in the PUE in the presence of 20% TMP.

• 접착 및 계면
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• 제13권2호
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• pp.53-57
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• 2012

Anisotropic conducting film (ACF)을 형성하기 위해서는 경화과정에 잠재성이 있어야만 하며, 보다 빠른 생산성을 갖기 위해서는 반응속도가 매우 높아야 한다. 이 연구에서는 여러 가지의 sulfonium 염들을 합성해서 epoxy 수지의 잠재성 경화제로 사용해 보았다. 이들 sulfonium 염들은 모두 우수한 잠재성을 보여 주었다. Differential scanning calorimetry (DSC)를 이용해서 이들의 경화거동을 살펴보았으며, $150^{\circ}C$에서의 경화 속도를 탐침법으로 측정하였다.

• Archives of Pharmacal Research
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• 제9권2호
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• pp.75-79
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• 1986

The effect of phenothiazine derivatives on the thermotropic transition of liposomal lipid bilayer made of dipalmitoyl phosphatidylchline and dipalmitoyl phosphatidic acid was investigated with differential scanning calorimetry. The thermograms of the liposomal bilayer incorporated with levomepromazine, chlopromazine, prochloperazine, perphenazine and fluphenazine were obtained and the size of cooperative unit of the transition were calculated from the ratio of the van't Hoff enthalpy change to the calculated enthalpy change of the transition. The results showed that incorporation of phenothiazine derivatives into the liposomal bilayer reduced the transition temperature at which the transition from solid state to liquid-crystalline state occurs, and broadened the thermogram peaks. Phenothiazine derivatives also significantly reduced the size of cooperative unit of the transition. The effect of the drugs was proportional to the concentration of the drug in the bilayer. This means that phenothiazine derivatives might have significant fluidizing effects on the biomembrane. The sizes of cooperative unit were successfully corrlated with phar-macological activities of the drugs and the surface pressure increases of lipid monolayer by these drugs. These correlations might be ascribed to a possible hydrophobic nature of interaction between the biomembrane and the drugs involved in their pharmacology.

• 한국초전도ㆍ저온공학회논문지
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• 제7권3호
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• pp.39-42
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• 2005

In this paper, the thermal characteristics of multilayer insulation (MLI) were experimentally investigated by using boil-off calorimetry method for seeking optimum standards of thermal insulation conditions. It is necessary to design the thermal insulating efficiency for applying to cryogenic instruments such as HTS power cable system. It is well known that the thermal characteristics and heat transfer of MLI are greatly affected by various MLI structures such as the number of layers and layer density, etc. However, it is difficult to know the thermal characteristics of MLI correctly. The heat leak by MLI between room temperature and liquid nitrogen temperature was measured at various conditions using a cylindrical cryostat. The cryostat consists of two guard vessels located at both end sides and a test vessel between them. The guard vessels are also filled with liquid nitrogen to prevent radiation heat leak through the both end side of the cylindrical test vessel to measure the heat leak only through MLI.

• Preventive Nutrition and Food Science
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• 제4권4호
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• pp.215-220
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• 1999

The Physical properties of corn starch were investigated by scanning electron microscopy, X-ray diffractometry and differential scanning calorimetry during the formation of enzyme-resistant starch(RS). Samples were studied in their native states and after annealing at 50, 55, 60 and 65℃ in excess water(starch : water=1:3) for 48hr. Starch granules became smaller and more rounded after annealing than in their native state. Annealing did not change the X-ray profile of native corn starch. After autoclaving-cooling cycles, native starch lost most of its crystallinity but annealed ones showed some of their crystallinity left as diffuse or poor B-type, which didn't relate to increasing Rs yields. During formation of RS, however, both native and annealed starches changed their X-ray profile from A-type to poor B-type of retrograded amylose. Annealing caused an increase in gelatinization temperature and enthalpy, but a narrowing of gelatinization temperature range. Only starch annealed at 65℃, however, showed a decrease in enthalpy even though its gelatinization temperature increased, which appeared to be due to the partial gelatinization in the amorphous region during annealing. Peak height index(PHI), the ratio of ΔH to Ti-To, increased by annealing. PHI values, therefore, showed the possibility as an indicator to predict RS yield which cannot be differentiated by differential scanning calorimetry and X-ray diffraction data.

• Preventive Nutrition and Food Science
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• 제15권4호
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• pp.356-359
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• 2010

Glass transition phenomena in nine Korean pure honeys (moisture content 18.3~20.1%) and honey-water mixtures by different water contents (0, 2, 5, and 10% w/w) were investigated with modulated different scanning calorimetry (MDSC). The total, reversing, and non-reversing heat flows were quantified during heating using MDSC. Glass transition was observed from reversing heat flow separated from the total heat flow. The glass transition temperatures ($T_g$) of pure honeys, which are in the range of $-42.7^{\circ}C$ to $-50.0^{\circ}C$, varied a lot with low determination coefficient ($R^2$=0.63), whereas those of honey-water mixtures decreased with a decrease in honey content. The $T_g$ values were also more significantly different among honey-water mixtures when compared to pure honeys, indicating that in the honey-water mixture system the $T_g$ values appear to be greatly dependent on moisture content. The measured heat capacity change (${\Delta}C_p$) was not influenced by moisture content.

• Transactions on Electrical and Electronic Materials
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• 제12권1호
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• pp.20-23
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• 2011

Amorphous Ti-(50-x)Ni-xCu (at%) (x = 20, 25, 27, 30) alloy ribbons were prepared by melt spinning. Subsequently, the crystallization behavior of the alloy ribbons was investigated by X-ray diffraction and differential scanning calorimetry. ${\Delta}T$ (the temperature gap between $T_g$ and $T_x$) increased from 33 K to 47 K and the wavenumber ($Q_p$) decreased from 29.44 $nm^{-1}$ to 29.29 $nm^{-1}$ with increasing Cu content from 20 at% to 30 at%. The activation energy for crystallization decreased from 188.5 kJ/mol to 170.6 kJ/mol with increasing Cu content from 20 at% to 25 at%; afterwards, the activation energy remained near constant. Crystallization occurred in two-stage: amorphous-B2-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content less than 25 at%, while it occurred in three-stage; amorphous-B2-TiCu-$TiCu_2$ in Ti-Ni-Cu alloys with Cu content more than 27 at%.

• 한국안전학회지
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• 제20권3호
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• pp.27-33
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• 2005

The shape memory effect in Ti-50.4at.%Ni alloy after solution treatment at 1273K for 2h and aged at 350, 450, $550^{\circ}C$ for 0.5, 1, 1.5, 2, 4, 10hrs had been investigated by differential scanning calorimetry measurement. It was found that ageing in the temperature range of $350^{\circ}C{\sim}550^{\cric}C$ induced complex transformation behavior, involving the R-phase and multiple-stage martensitic transformation. Usually aged Ni-rich NiTi alloys undergo martensitic transformation on cooling from high temperatures in two step : Austenite to R-phase and then R-phase to Martensite (normal behavior). In sample aged at $350^{\circ}C$ two distinct DSC peaks arised giving evidence of intermediate stages of martensite transformation. This results in the nucleation and growth of coherent $Ni_4Ti_3$-precipitate. These explain all features of the evolution of DSC charts during ageing including the number of distinct DS peaks and their positions.

• 한국안전학회지
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• 제24권4호
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• pp.40-46
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• 2009

The early identification of thermal hazards associated with a process such as the heats of reaction, exothermic decompositions, and the understanding of thermodynamics before any large scale operations are undertaken. The evaluation of reaction factors and thermal behavior on esterification process in manufacture of concrete mixture agents are described in the present paper. The experiments were performed in the differential scanning calorimetry(DSC), C 80 calorimeter, and thermal screening unit($TS^u$). The aim of the study was to evaluate the thermal stability of single material and mixture in esterification process. We provided the thermal data of chemical materials to present safe operating conditions through this study.