• 대한화학회지
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• 제7권4호
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• pp.288-292
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• 1963

The rates of reaction of various Korean anthracites with carbon dioxide were measured at temperatures ranging from $850^{\circ}C$ to $1100^{\circ}C$ with coal -6, +8 sieve size and the residence time of reactant gas in the fixed coal bed 14.0 to 15.0 seconds. The primary variables studied were the coal sources and temperature. The reactivity was considerably varies with the coal sources and the general trends show that the reactivity sharply increases with increasing reaction temperature except the Yongwol coal where the increase is not so sharp, which is considered to be due to high reactivity and high-pore structure of the coal. It was also found that a straight line was produced when a logarithm of the rate constant is plotted against the reciprocal of the absolute temperature up to 1000^${\circ}C$, but above that temperature it deviates from linearity. The information obtained will be of value in the design of the coal gasifier using Korean anthracites.

• 한국환경농학회지
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• 제35권2호
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• pp.128-136
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• 2016

BACKGROUND: Hydrothermal carbonization reaction is the thermo-chemical energy conversion technology for producing the solid fuel of high carbon density from organic wastes. The hydrothermal carbonization reaction is accompanied by the thermal hydrolysis reaction which converse particulate organic matters to soluble forms (hydro-thermal hydrolysate). Recently, hydrothermal carbonization is adopted as a pre-treatment technology to improve anaerobic digestion efficiency. This research was carried out to assess the effects of hydro-thermal reaction temperature on the methane potential and anaerobic biodegradability in the thermal hydrolysate of organic sludge generating from the wastewater treatment plant of poultry slaughterhouse .METHODS AND RESULTS: Wastewater treatment sludge cake of poultry slaughterhouse was treated in the different hydro-thermal reaction temperature of 170, 180, 190, 200, and 220℃. Theoretical and experimental methane potential for each hydro-thermal hydrolysate were measured. Then, the organic substance fractions of hydro-thermal hydrolysate were characterized by the optimization of the parallel first order kinetics model. The increase of hydro-thermal reaction temperature from 170℃ to 220℃ caused the enhancement of hydrolysis efficiency. And the methane potential showed the maximum value of 0.381 Nm³ kg^-1-VS_added in the hydro-thermal reaction temperature of 190℃. Biodegradable volatile solid(VSB) content have accounted for 66.41% in 170℃, 72.70% in 180℃, 79.78% in 190℃, 67.05% in 200℃, and 70.31% in 220℃, respectively. The persistent VS content increased with hydro-thermal reaction temperature, which occupied 0.18% for 170℃, 2.96% for 180℃, 6.32% for 190℃, 17.52% for 200℃, and 20.55% for 220℃.CONCLUSION: Biodegradable volatile solid showed the highest amount in the hydro-thermal reaction temperature of 190℃, and then, the optimum hydro-thermal reaction temperature for organic sludge was assessed as 190℃ in the aspect of the methane production. The rise of hydro-thermal reaction temperature caused increase of persistent organic matter content.

• Korean Chemical Engineering Research
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• 제46권1호
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• pp.189-193
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• 2008

본 연구는 zinc aluminate 촉매를 사용한 고압연속식 고정층 반응시스템에서의 대두유와 메탄올의 transesterification에 관한 것이다. 바이오디젤 제조를 위한 고압 연속식 고정층 촉매 반응에서 반응 조건이 메틸에스터 생성에 미치는 영향이 주로 조사되었다. 촉매가 없는 경우, 거의 모든 반응 조건에서 메틸에스터의 수율이 4.5% 이하로 매우 낮았지만, $300^{\circ}C$, 1,200 psi 조건에서는 19%의 메틸에스터 수율을 보여 주었다. 이는 반응 조건이 메탄올의 초임계점에 근접하였기 때문으로 보인다. 촉매 반응에서는 무촉매 반응과 비교하여 비교적 낮은 온도와 압력에서도 높은 메틸에스터 수율을 보여주었다. 또한 수율에 미치는 반응 조건의 영향을 살펴본 결과, 반응온도, 압력, 반응물에서 메탄올 몰비가 높을수록 높은 메틸에스터 수율을 보여주었다. 반응 변수 중에서도 반응온도가 메틸에스터 수율에 가장 큰 영향을 미치는 것으로 확인되었다.

• 한국재료학회지
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• 제18권3호
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• pp.153-158
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• 2008

Fe-aluminides have the potential to replace many types of stainless steels that are currently used in structural applications. Once commercialized, it is expected that they will be twice as strong as stainless steels with higher corrosion resistance at high temperatures, while their average production cost will be approximately 10% of that of stainless steels. Self-propagating, high-temperature Synthesis (SHS) has been used to produce intermetallic and ceramic compounds from reactions between elemental constituents. The driving force for the SHS is the high thermodynamic stability during the formation of the intermetallic compound. Therefore, the advantages of the SHS method include a higher purity of the products, low energy requirements and the relative simplicity of the process. In this work, a Fe-aluminide intermetallic compound was formed from high-purity elemental Fe and Al foils via a SHS reaction in a hot press. The formation of iron aluminides at the interface between the Fe and Al foil was observed to be controlled by the temperature, pressure and heating rate. Particularly, the heating rate plays the most important role in the formation of the intermetallic compound during the SHS reaction. According to a DSC analysis, a SHS reaction appeared at two different temperatures below and above the metaling point of Al. It was also observed that the SHS reaction temperatures increased as the heating rate increased. A fully dense, well-bonded intermetallic composite sheet with a thickness of $700\;{\mu}m$ was formed by a heat treatment at $665^{\circ}C$ for 15 hours after a SHS reaction of alternatively layered 10 Fe and 9 Al foils. The phases and microstructures of the intermetallic composite sheets were confirmed by EPMA and XRD analyses.

• 한국세라믹학회지
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• 제32권8호
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• pp.931-937
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• 1995

AlN powder and whiskers were synthesized by direct nitridation of aluminum powder in pure nitrogen atmosphere. The nitridation reaction of aluminum powder was initiated by heating the sample to the ignition temperature and the reaction was finished in less than 3 minutes. AlN whisker-shaped morphology was observed predominantly when the sample was heated above 90$0^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.38-41
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• 2001

The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The influence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of $MoSi_2$ during SHS might be different and depending on experimental conditions.

• 한국세라믹학회지
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• 제15권1호
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• pp.28-34
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• 1978

In order to develop the high refractory composite materials consisting of mullite and carborundum, Hadong kaolin and coal coke were selected as the starting materials. Silicone carbide crystals formed during the high-temperature reaction between kaolin and coke were detected by X-ray diffraction method and identified by electron diffraction. The temperature at which the amorphous silicone carbide begins to crystallize could be assumed to be about 155$0^{\circ}C$, which is the lower temperature claimed by others.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집
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• pp.38-41
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• 2001

The combustion characteristics of the disilicides molybdenum system have been studied experimentally. The pertinent reaction parameters that control self-propagating high temperature synthesis reactions have been examined. These include reactant particle size, powder mixing and compaction, reaction stoichiometry, diluents. The inf1uence of experimental variables on integrity, uniformity, structure, and related material properties will be discussed. Formation mechanism of MoSi$_2$ during SHS might be different and depending on experimental conditions.

• 유기물자원화
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• 제22권1호
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• pp.27-34
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• 2014

하수슬러지의 처리 및 재활용에 관한 다양한 연구가 진행되었지만 하수슬러지 내에 포함된 80% 이상의 함수율에 따른 높은 에너지 소비 비용으로 저비용의 처리 기술의 요구가 높다. 이에 본 연구에서는 슬러지 처리 시 적은 양에 에너지를 소비하는 열가용화 반응을 적용하여 열가용화 반응온도에 따른 하수슬러지의 점도를 정량화하고자, 반응온도에 따른 탈수슬러지의 토크를 연속적으로 측정하였다. 반응온도가 증가하면 높은 반응온도와 압력에 의해 탈수슬러지는 열가용화 진행되고 슬러지 세포내의 결합수가 자유수로 용출되어 고상의 탈수슬러지는 액상의 슬러리로 변환된다. 이에 반응온도에 따른 점도 측정 결과 293K에서는 $270,180kg/m{\cdot}sec$ 로 높은 점도 값을 보이지만 400K에서는 $12kg/m{\cdot}sec$ 급격히 감소하고 460K 이상에는 $4kg/m{\cdot}sec$로 물의 점도와 유사한 값을 나타낸다. 이 결과를 바탕으로 수치모델링으로 열가용화 반응기 최적 설계를 위한 경계조건으로 점도 함수를 확보하였다.

• Preventive Nutrition and Food Science
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• 제2권4호
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• pp.321-327
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• 1997

High Temperature-cooking conditions of cultured fishes(loach, crucian carp, bastard halibut, and jacopever) were optimized by response surface methodology(RSM), and plastein products were prepared using enzymatic hydrolysis. Four models were proposed with regard to effects of time(t), temperature(T), and water/fish meat (w/f) ratio on the amount of 0.3M TCA soluble fractions. The model coefficients were ranged from p<0.0001 for jacopever to p<0.0433 for bastared halibut. Cooking conditions for 60% hydrolysis were optimized at 1) 14$0^{\circ}C$ except for crucian carp(136$^{\circ}C$); 2) 10.08 hours(loach), 7.25 hours(crucian carp), 9.85 hours(ba-stard harlibut), and 9.37 hours(iacopever); 3) 1:1(w/f) ratio except for the crucian carp(1.1:1). When protein hydrolyzates were employed for the plastein synthesis, optimum plastein-reaction conditions were determined to be pH 9.0 with chymotrypsin for the loach and crucian carp hydrolyzates, pH 9.0 with papain for the bastard halibut hydrolyzate, and pH 11.0 with trypsin for the jacopever hydrolyzate. Plastein reaction could be performed in water at concentration up to 20%(w/f).