• Title/Summary/Keyword: Thermal reaction

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Some Molecular Characteristics and Improving Methods for Thermal Stability of Enzyme (효소단백질 열안정성의 분자구조적 특성 및 증진기법)

  • 김남수;김수일
    • Microbiology and Biotechnology Letters
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    • v.19 no.1
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    • pp.100-108
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    • 1991
  • Molecular characteristics and improving methods for thermal stability of enzyme have been considered. Intrinsic and extrinsic stabilizing mechanisms are two governing principles for enhanced thermal stability of enzyme in molecular basis. Factors contributing to the former and the latter mechanisms may be involved in the enhanced thermal stability of enzyme complementarily. Also, the methods for improving thermal stability of enzyme which comprise reaction in organic solvent system, chemical modification, immobilization, sequential unfolding and refolding, gene manipulation techniques and enzyme-antibody complexing are reviewed.

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Solar Thermal Hybrid Power Generation;technology review and system design (태양열복합발전 기술개발 동향 및 설계)

  • Kim, Jin-Soo;Kang, Yong-Heack;Lee, Sang-Nam;Yun, Hwan-Ki;Yu, Chang-Kyun;Kim, Jong-Kyu
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.06a
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    • pp.684-687
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    • 2007
  • Research on the solar thermal hybrid power generation technology which uses solar thermal chemical reaction has been carried out in KIER, The research covers development of solar concentration system and solar reactor for methane steam reforming reaction. This paper introduces a brief review and prospects of oversea's researches in similar areas and KIER's research progresses up to now.

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Enhanced of Bio-Hydrogen Production from Microalgae by Thermal Pre-Treatment (열처리를 통한 미세조류로부터 바이오수소 생산 향상)

  • Lee, Chaeyoung;Choi, Jaemin
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.4
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    • pp.275-281
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    • 2013
  • This study was conducted to increase the amount of bio-hydrogen production from microalgae(Chlorella vulgaris) in batch reactors by thermal pre-treatment. The optimization of thermal pre-treatment was conducted using statistic experimental design of response surface methodology. Two experimental parameters of temperature and reaction time were considered. The optimization condition was founded at the coded variables of <0.52, -0.07> corresponding to the experimental of heating temperature of $95.6^{\circ}C$ and reaction time of 57.9 min, respectively. Under the optimal condition, the maximum hydrogen production was predicted to 25.3mL $H_2/g$ dry cell weight (dcw), which was 9.1 times higher value of control(2.8mL $H_2/g$ dcw).

Influence of Sulfur Fertilization on the Antioxidant Activities of Onion Juices Prepared by Thermal Treatment

  • Koh, Eunmi;Surh, Jeonghee
    • Preventive Nutrition and Food Science
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    • v.21 no.2
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    • pp.160-164
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    • 2016
  • Two onions (Sulfur-1 and Sulfur-4) cultivated with different sulfur applications were thermally processed to elucidate the effects of heat treatment on browning index and antioxidant activity. Sulfur-4 onion had higher sulfur content compared with the Sulfur-1 onion. After thermal processing, browning intensity was different between the two onions juices, with lower values observed for Sulfur-4 onion juice. This suggests that sulfur inhibits the Maillard browning reaction. The total reducing capacity of the juices increased at higher thermal processing temperatures; however, it was also lower in the Sulfur-4 onion juice. This suggests that the heat treatment of onions enhanced their antioxidant activity, but the effect was offset in the Sulfur-4 onion juice presumably due to higher sulfur content. This study indicates that sulfur, a core element for the functionality of onions, can decrease the antioxidant activity of thermally processed onions because of its potential as a Maillard reaction inhibitor.

Predicting Thermo-mechanical Characteristics from the 2nd Phase Fraction of Al-AlN Composites for LED Heat Sinks with FEM (유한요소해석을 이용한 방열용 Al-AlN 복합재의 제2상 분율에 따른 열-기계적 특성예측)

  • Yoon, Juil
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.5
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    • pp.137-142
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    • 2018
  • With the development of the electronic-materials industry, multi-functional metal-composite materials with high thermal conductivity and low thermal expansion must be developed for high reliability and high life expectancy. This paper is a preliminary study on the manufacturing technology of gas reaction control composite material, focusing on the prediction of the equivalent thermal properties of Al-AlN composite materials. Numerical equivalent property values are obtained by using finite element analysis and compared with theoretical formulas. Al-AlN composite materials should become the optimal composite material when the proportion of the reinforcing phase is less than 0.5.

A Study on the Viscosity Characteristics of Dewatered Sewage Sludge according to Thermal Hydrolysis Reaction (열가용화 반응에 의하여 탈수된 하수슬러지의 점도 특성에 관한 연구)

  • Song, Hyoung Woon;Han, Seong Kuk;Kim, Choong Gon;Shin, Hyun Gon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.22 no.1
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    • pp.27-34
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    • 2014
  • demand for a low-cost treatment technology is high because the sewage sludge has an 80% or higher water content and a high energy consumption cost. This study apply the thermal hydrolysis reaction that consumes a small amount of energy for sludge treatment. The purpose of this study is to quantify the viscosity of sewage sludge according to reaction temperature. we measured continuously the torque of dewatered sludge by the reaction temperature. As the reaction temperature increased, the dewatered sludge is thermal hydrolysis under a high temperature and pressure. Therefore, the bond water in the sludge cells comes out as free water, which changes the dewatered sludge from a solid phase to slurry of a liquid phase. The results of the viscosity measurements according to the reaction temperature showed that the viscosity was very high at $270,180kg/m{\cdot}sec$ at a temperature of 293K, but rapidly decreased with increases in the reaction temperature to $12kg/m{\cdot}sec$ at a temperature of 400K and to $4kg/m{\cdot}sec$ at a temperature of 460K or higher, similar to the changes in the viscosity of water. And we was obtained the viscosity function of boundary condition for the optimal design of thermal hydrolysis reactor by numerical modeling based on the this results.

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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    • 2006.08a
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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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NOx Formation Characteristics in Diffusion, Partial Premixed and Premixed Jet flame (가스 연료의 연소 방식에 따른 NOx 생성 특성)

  • Choi, Young-Ho;Lee, Chang-Eon
    • 한국연소학회:학술대회논문집
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    • 1998.10a
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    • pp.155-164
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    • 1998
  • Numerical analysis was performed with multicomponent transport properties and detailed reaction mechanisms for axisymetric 2-D CH4 jet diffusion, partial premixed, premixed flame. Calculations were carried out twice with C2-Full Mechanism including prompt NO reaction in addition to the above C2-Thermal NO Mechanism. The role of thermal NO mechanism and prompt NO mechanism on each flame's NO production is investigated by using the numerical result. The NOx production of each flame were evaluated Quantitatively in terms of the NOx emission index

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Photodecomposition Mechanism of 2-Methoxy-1,2-diphenyl Diazoethane

  • Seong, Dae Dong;Im, Gwi Taek;Kim, Min Sik;Park, Dong Gyu
    • Bulletin of the Korean Chemical Society
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    • v.16 no.1
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    • pp.47-52
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    • 1995
  • The mechanism of the photodecomposition of 2-methoxy-1,2-diphenyl diazoethane has been investigated in methanol and isoprene using time-resolved laser flash photolysis techniques. The reaction of triplet carbene which is generated from 2-methoxy-1,2-diphenyl diazoethane with methanol is believed to proceed via thermal excitation to the singlet state. The activation energy and enthalpy are consistent with a mechanism involving thermal equilibrium between the triplet and singlet state followed by the reaction of the singlet with methanol to give ether.