• KSBB Journal
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• 제4권2호
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• pp.128-133
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• 1989

미생물에 의한 단백질 분해 효소인 protease생산에 있어 탄소원과 질소원의 영향은 매우 중요한 것으로 알려져 있다. Bacillus licheniformis에 의한 protease생산에 있어서 탄소원과 질소원의 영향을 규명하기 위해서 제한배지를 사용하여 회분식 배양을 수행하였다. 탄소원의 농도가 높을수록 그리고 질소원의 농도가 높을수록 Bacillus licheniformis의 성장은 촉진되나 proteased의 생합성 비율은 감소됨을 알았다. 또한 회분식 배양 결과로부터 탄소원과 질소원의 영향을 고려한 수학적 모델식을 제안하였으며 제안된 수학적 모델식을 사용하여 탄소원과 질소원을 적절히 공급하므로서 protease의 생산성을 증대시킬 수 있었다.

• Journal of Electrochemical Science and Technology
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• 제7권2호
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• pp.139-145
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• 2016

The electrochemical performance of carbon-coated LiMn₂O₄ nanoparticles was reported. The polydopamine layer was introduced as a new organic carbon source. The carbon layer was homogeneously coated onto the surface of the LiMn₂O₄ nanoparticles because the polymerization process from the dopamine solution (in a buffer solution, pH 8.5) easily and uniformly formed a polydopamine layer. The phase integrity of LiMn₂O₄ deteriorated during the carbon-coating process due to oxygen loss, although the main structure was maintained. The carbon-coated sample led to improved rate capability because of the effect of the conductive carbon layer. Moreover, the carbon coating also enhanced the cyclic performance. This indicates that the carbon layer may suppress unwanted side reactions with the electrolytes and compensate for the low electronic conductivity of the pristine LiMn₂O₄.

• 한국세라믹학회지
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• 제36권6호
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• pp.655-661
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• 1999

${\beta}$-SiC formation mechanism in Si melt-C-SiC system with varying in size of carbon source was investigated. A continuous reaction sintering process using Si melt infiltration method was adopted to control the reaction sintering time effectively. It was found that ${\beta}$-SiC formation mechanism in Si melt-C-SiC system was directly affected by the size of carbon source. In the Si melt-C-SiC system with large carbon source ${\beta}$-SiC formation mechanism could be divided into two stages depending on the reaction sintering time: in early stage of reaction sintering carbon dissolution in Si melt and precipitation of ${\beta}$-SiC was occurred preferentially and then SIC nucleation and growth was controlled by diffusion of carbon throughy the ${\beta}$-SiC layer formed on graphite particle. Furthmore a dissolution rate of graphite particles in Si melt could be accelerated by the infiltration of Si melt through basal plane of graphite crystalline.

• 산업기술연구
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• 제16권
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• pp.13-24
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• 1996

This research aims to investigate the effects of an internal carbon source in the denitrification of piggery wastewater. In this study, the raw wastewater and the effluent from each of anoxic basin and anaerobic basin were used as the internal carbon sources. The experiments were carried out in batch system and the results are as follows ; i) Denitrification rates were the highest in the raw wastewater and the lowest in the anaerobic effluent. ii) The piggery wastewater contained about 60 percent of the readily biodegradable organic(RDCOD), which led to a conclusion that the raw wastewater could be used as the internal carbon source for the denitrification. For the efficient denitrification, pre-denitrification process was found profitable. iii) In denitrification, alkalinity production rates were in the range of 3.4 to $3.6mgCaCO_3/mgNO_3-N$. iv) The denitritation of piggery wastewater came out to be possible, and the rate of organic carbon consumption decreased about 10 percent.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
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• pp.159-164
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• 1997

Pyrolytic carbon layer was coated on A1203 balls by fluidized bed type chemical vapour deposition unit to develop the coating technology for the preparation of coated nuclear fuel. The deposition was carried out at the temperature ranges between 110$0^{\circ}C$ and 130$0^{\circ}C$ with various gas contents and flow rates. Source and carrier gas were propane and argon, respectively. X-ray analysis shows that the deposition layer was typical carbon spectra. The growth rate of carbon layer depended on the amount of source gas and the deposition temperature. For the alumina balls with 2mm in diameter, the deposition rate was 11${\mu}{\textrm}{m}$/hr in the flow gases containing 30% source gas at 130$0^{\circ}C$ with a total flow rate of 2.0$\ell$/min. Microstructural observation of the deposits with scanning electron microscope revealed that the deposits had relatively dense and isotropic structure. Chemical analysis by energy dispersive spectroscopy showed that the layer was pure carbon.

• 대한환경공학회지
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• 제28권5호
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• pp.480-486
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• 2006

B시 S하수처리장에서 화학침전 공정에서 MLE 공정으로 공법을 변경하였으며, 생물학적으로 탈질시 부족한 탄소원을 보충하기 위해 외부탄소원이 요구되었다. 본 연구에서는 약 4.7%의 아세트산을 포함하는 TPA(Terephthalic Acid) 생산부산물의 대체탄소원으로 적용 가능성을 평가하기 위해 NUR(Nitrate Uptake Rate) 및 OUR(Oxygen Uptake Rate) 실험과 현장 적용실험을 수행하였다. 실험 결과 TPA 생산 부산물은 일반 상용 외부탄소원으로 널리 쓰이는 메탄올보다 빠른 순응특성을 나타내었고 비탈질율이 $8.24mg{NO_3}^--N/gVSS/hr$, 단위 질산성 질소 제거당 COD 소모비는 $3.70COD_{Cr}/g\;NO_3$, RBDCOD 함량 99.4%로 나타났다. S하수처리장에 대한 TPA 생산부산물 현장 적용 실험을 통해 안정적인 영양염류 제거효율을 나타내었으며 방류수 T-N 농도가 8.2 mg/L로 생물학적 탈질에 요구되는 탄소원을 보충할 수 있는 대체탄소원으로 적합하다고 판단되었다.

• 유기물자원화
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• 제13권4호
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• pp.128-135
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• 2005

본 연구에서는 CFSTR(Continuous-flow Stirred-Tank Reactor) 형식의 반응조에 담체가 채워진 호기-혐기조합 공법에 따른 질산화 및 탈질화에 관한 효율의 증대와 유입수 및 침전조 상등액의 유량대비를 조절 하므로써 질소제거의 효율 증대에 관한 방법을 모색하고자 하였다. 탈질조 내의 탈질효율에 비례하여 포기 반응조 내의 질산성 질소 농도를 산출하고자 유입수와 침전조 내에서의 상등액을 탈질조로 반송하여 유입하고 유입수와 반송되는 침전조 상등액 유입의 유량대비를 통하여 최종적으로 반응조에 대한 질소제거의 효율을 파악하고자 하였다. 적절한 유량대비를 이용하였을 때 탈질조 내의 필요한 탄소원의 공급이 유입수로 통해 이루어지는 것으로 판단되어지며, 외부탄소원의 주입 없이 유입수 만으로도 완벽하게 탈질이 이루어지는 것을 확인 할 수 있었다. 하지만 유입수와 침전조 상등액의 유량대비에서 침전조 상등액의 유량비가 커지면 커질수록 유입수내의 탄소원의 유입이 줄어들기 때문에 이에 대한 탄소원의 농도에 대한 산정이 중요하다고 생각된다.

• 한국미생물·생명공학회지
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• 제24권4호
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• pp.493-499
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• 1996

Lactan gum produced by Rahnella aquatilis is a high viscous, anionic polysaccharide and has shear thinning behaviour. Lactan gum yield and cencentration was greater on disaccharide such as lactose and sucrose than on monosaccharides such as glucose and galactose. When initial carbon source concentration was 45g/l of sucrose of lactose, the microorgnisms produced 28 g/l and 27 g/l of lactan, respectively with a yield more than 60%. $\beta$-Galactosidase, hydrolyzing lactose into galactose and glucose, was induced by lactose or galactose. When initial corbon source was 45 g/l of mixed carbon I (glucose:galactose=1:1), lactan gum concentaration was higher than that from 45 g/l of monosaccharide (glucose pf galactose) but was similar to the result from 45 g/l of lactose. Therefore, lactose hydrolysis reaction by $\beta$-galactosidase does not seem to be a rate determining step in lactan gum biosynthesis. When initial carbon source was 45 g/l of mixed carbon II (glucose:fructose=1:1). total carbon source consumption rate was slower than that from sucrose, but glucose consumption rate was faster than that from fructose.

• Journal of Microbiology and Biotechnology
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• 제12권6호
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• pp.979-985
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• 2002

The possibility of microalgal nitrogen treatment was tested in wastewaters with a low carbon/nitrogen (C/N) ratio. Chlorella kessleri was cultured in the two different artificial wastewaters with nitrate as a nitrogen source: one contained glucose for an organic carbon source and the other without organic carbon sources. The growth rates of the two cultures were almost identical when the aeration rate was over 1 vvm. These results suggest that microalgae could successfully remove nitrogen from wastewater, as far as the mass transfer of $CO_2$, was not limited. Nitrate was successfully reduced to below 2 mg $NO_3^-$-N/ml from the initial nitrate concentration of 140 mg $NO_3^-$-N/ml in 10 days, even in the wastewater with no organic carbon source. Similar results were obtained when ammonium was used as the sole nitrogen source instead of nitrate. Higher concentrations of nitrogen of 140, 280, 560 and 1,400 mg/ml were also tested and similar amounts of nitrogen were removed by algal cultures without showing any substrate inhibition.

• 상하수도학회지
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• 제13권4호
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• pp.45-53
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• 1999

The microbial organisms named "Pseudomonas sp. LK-14" were isolated from farm land and shallow river sediment, activated, augmented and identified; which were using 2,4-D (2,4-Dichlorophenoxyacetic acid) as a sole carbon source and energy source. 2,4-D removal efficiency of LK-14 with 2,4-D sole carbon source (reactor S) were higher than that of Activated Sludge with 2,4-D sole carbon source (reactor A). Dynamic bioligical reaction kinetic parameters (sole carbon source was 2,4-D) obtained from batch reactor experiments were ${\mu}_{max}$ $0.105hr^{-1}$, $K_{s,24D}$ 15.64mg/L, $K_{i,24D}$ $1.94h^{r-1}$, $Y_{24D}$ 0.39 for LK-14 and ${\mu}_{max}$ $0.008hr^{-1}$, $K_{s,24D}$ 26.95mg/L, $K_{i,24D}$ $1.75hr^{-1}$, $Y_{24D}$ 0.10 for Activated Sludge. Using these parameters, we could predict the behaviors of 2,4-D substrate utilized by LK-14 and Activated Sludge in batch reactors. The kinetic parameters are enable to predict the 2,4-D substrate and microbial population behavior entering into wastewater treatment plants by using unsteady states dynamic simulation modeling technique.