• 한국미생물·생명공학회지
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• 제15권2호
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• pp.98-103
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• 1987

이상계를 이용해서 올리브유를 가수분해하는 데 있어서, 리파제의 반응동력학을 검토했다. 반응계는 Candide rugosa와 Rhizopus arrhizus 리파제를 수용액상에 녹이고 기질인 올리브유를 유기용매인 이소-옥탄에 녹여서 서로의 계면에서 효소반응이 일어나는 이상계 반응이다. 각각의 리파제에 대해서 이소-옥탄에 올리브유를 여러 농도로 녹여서 유지 분해속도를 측정함으로써 리파제의 반응 동역학을 보았다. 이상계 내에서 반응 속도 방정식은 일반 효소의 속도 방정식의 Michaelis-Menten식을 따르지 않았다. 이 결과는 이상계에서 유기용매내의 올리브유의 농도가 계면면적의 변화에 영향을 주기 때문에 비롯되는 것으로 생각된다. 그래서 올리브유의 농도가 계면면적에 영향을 주지 않는다고 가정한 식에 변형을 가해서 새로운 식을 유도했다. 이 식은 특히 올리브유가 낮은 농도에서 심하게 Michaelis-Menten 식에서 벗어나는 현상을 설명할 수 있다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.210-213
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• 2008

The purpose of this study is to investigate the performances of organic removal and methane recovery in the full scale two-phase anaerobic system. The full scale two-phase anaerobic system was consists of an acidogenic ABR (Anaerobic Baffled Reactor) and a methanognic UASB (Upflow Anaerobic Sludge Blanket) reactor. The volume of acidogenic and methanogenic reactors is designed to 28.3 $m^3$ and 75.3 $m^3$. The two-phase anaerobic system represented 60-82% of COD removal efficiency when the influent COD concentration was in the range of 7,150 to 16,270 mg/L after screening (average concentration is 10,280 mg/L). After steady-state, the effluent COD concentration in the methanogenic reactor showed 2,740 $\pm$ 330 mg/L by representing average COD removal efficiency was 71.4 $\pm$ 8.1% when the operating temperature was in the range of 19-32$^{\circ}C$. The effluent SCOD concentration was in the range of 2,000-3,000 mg/L at the steady state while the volatile fatty concentration was not detected in the effluent. Meanwhile, the COD removal efficiency in the acidogenic reactor showed less than 5%. The acidogenic reactor played key roles to reduce a shock-loading when periodic shock loading was applied and to acidify influent organics. Due to the high concentration of alkalinity and high pH in the effluent of the methanogenic reactor, over 80% of methane in the biogas was produced consistently. More than 70 % of methane was recovered from theoretical methane production of TCOD removed in this research. The produced gas can be directly used as a heat source to increase the reactor temperature.

• 산업기술연구
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• 제5권
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• pp.73-79
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• 1985

Thermodynamic calculation for the CVD of SiC from methyltrichlorosilane(MTS) was done in some range of deposition condition to identify optimum condition. The results show that the most considerable chemical species are chloride and chlorosilane for silicon source and methane and acetylene for carbon source. In order to yield single phase ${\beta}$-SiC it is believed that optimum temperature range is between 1500 and $1700^{\circ}k$. With increasing temperature, stable phase is changed from Si+SiC phase to C+SiC phase. It is believed because equilibrium concentration of silicon source decrease and equilibrium concentration of carbon source increases with increasing temperature.

• 대한화학회지
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• 제38권2호
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• pp.129-135
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• 1994

Acyclic polyether dicarboxylic acid는 액체막계에서 금속이온의 운반체로 연구되었다. 수소이온이 이온화될 수 있는 리간드는 금속이온의 이동에 수소이온이 반대방향으로 이동된다. 이와 같은 리간드는 pH를 변화시키면 효과적으로 금속이온을 분리할 수 있고 농축시킬 수도 있다. 금속이온의 이동은 source phase의 염기의 농도와 receiving phase의 산의 농도를 증가시키면 증가된다. Acyclic polyether dicarboxylic acids를 운반체로 사용한 경쟁이동반응에서 칼슘이온을 선택적으로 분리할 가능성이 있다.

• 반도체디스플레이기술학회지
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• 제7권2호
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• pp.1-5
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• 2008

Silicide formation process and the formation sequence were investigated in this study. It was postulated that the formation of the second silicide phase involves glass formation between the first silicide phase and Si given that a thin metal film is deposited on a Si substrate. The concentration of glass was assumed to be located where the free energy of the liquid alloy with respect to the first nucleated compound and solid Si (${\Delta}$G') is most negative. It was also mentioned that the glass concentration is close to the composition of the second phase in order to achieve the maximum energy degradation. It was shown that the minimum ${\Delta}$G' concentration can be estimated by interpolating the portion of the liquidus where the liquid alloy is in equilibrium with the two solid constituents, namely the first compound phase and Si, thereby forming a hypothetical eutectic.

• Food Science and Biotechnology
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• 제14권1호
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.

• 한국연초학회지
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• 제18권2호
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• pp.170-176
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• 1996

This paper describes the generation and decay phenomena of gas, vapor and particulate phase components of environmental tobacco smoke in 18 m3 controlled experimental atmosphere chamber. Real time-weighted average concentration ratios of markers were determinated at no ventilation rates and sampling durations of starting to smoking 45 min. Average concentration of major ETS markers was no significant on the mainstream smoke contents of commercial cigarette and decay ratios were dependent on first order kinetic. RSP/nicotine, solanesol and 3-EP were good predictors of ETS concentration in the public indoor field. The concentration ratio of vapor phase and particulate phase components is highly variable to assessment of indoor air quality with ETS. Key words : ETS, chamber study, ETS markers.

• Advances in Traditional Medicine
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• 제3권1호
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• pp.18-20
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• 2003

The purpose of this study was to examine the effect of supplementary highly purified chitosan (HPC) on blood alcohol concentration in healthy human. The human study was performed with two sections. Each section of the study was conducted by two-phase cross-over design with a week wash-out period. All volunteers took HPC in one phase, and took a placebo in the next phase. Blood alcohol concentrations were different between in those taking HPC and in those taking the placebo in the human. And the concentration of serum aspartate aminotransferase (AST, GOT) and alanine aminotransferase (ALT, GPT), the indicator of liver cell damage, was lowered in those taking HPC, compared to those taking the placebo. In conclusion, taking HPC prior to drinking alcohol can somewhat reduce alcohol concentration in human blood and liver cell damage.

• 한국세라믹학회지
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• 제36권8호
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• pp.853-858
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• 1999

To investigate the effect of H2 flow rate and TMS[Si(CH3)4] concentration on synthesizing ultrafine ${\beta}$-SiC powder by vapor phase reaction the experiment was performed at 1100$^{\circ}C$ of the reaction temperature under the condition of 200-2000 cc/min of H2 gas flow rate and 1-10% of TMS concentration respectively. The shape of ${\beta}$-SiC particles synthesized was spherical and the size of particles decreased and the distribution of particles was more uniform with increasing H2 gas flow rate. In this case Si powders were coexisted with ${\beta}$-SiC Pure and ultrafine ${\beta}$-SiC powders without Si were obtained under the condition of above 2% of TMS concentration and below 1500 cc/min of H2 gas flow rate.

• Journal of Microbiology and Biotechnology
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• 제9권4호
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• pp.498-503
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• 1999

Protease produced from Bacillus sp. FSE-68 was isolated from Meju, a Korean fermented soybean starter, and was purified by a two-consecutive aqueous two-phase system. The change of partition coefficient (K) in the polyethylene glycol (PEG)/potassium phosphate buffer (PPB) aqueous two-phase system was measured at different pHs (6.0- 9.2), PPB concentrations (8-12%), and temperatures (4 and $20^{\circ}C$). As the PPB concentration in the aqueous two-phase system increased, the protease concentration in the top phase (PEG-rich phase) increased, thereby enhancing the partition coefficient. The minimum partition coefficient of the protease was achieved at pH 7.0, whereas that of the total protein was at pH 6.0. The biggest difference in partition coefficients of total protein and protease occurred at pH 6.0. It was interesting to note that the partition coefficient of protease decreased as the temperature increased. The optimum condition of the primary aqueous two-phase extraction of Bacillus sp. FSE-68 was pH 6.0, 14% (w/w) PPB, and 16% (w/w) PEG at $4^{\circ}C$, and the crude enzyme concentration in this system was 50% (w/w). The protease, which was concentrated in the top phase, was further mixed with 15% (w/w) PPB (pH 7.0) in the ratio of 1:1 at $20^{\circ}C$ to elute the bottom phase (PPB-rich phase). Using these steps, the purification fold achieved was 9.2 with a 44.7% yield.