• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제21권4호
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• pp.225-244
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• 2017

The natural convective nanofluid flow and heat transfer inside a square enclosure with a center heater in the presence of magnetic field has been studied numerically. The vertical walls of the enclosure are cold and the top wall is adiabatic while the bottom wall is considered with constant heat source. The governing differential equations are solved by using a finite volume method based on SIMPLE algorithm. The parametric study is performed to analyze the effect of different lengths of center heater, Hartmann numbers and Rayleigh numbers. The heater effectiveness and temperature distribution are examined. The effect of all pertinent parameters on streamlines, isotherms, velocity profiles and average Nusselt numbers are presented. It is found that heat transfer increases with the increase of heater length, whereas it decreases with the increase of magnetic field effect. Furthermore, it is found that the value of Nusselt number depends strongly upon the Hartmann number for the increasing values of Rayleigh number.

• Journal of Microbiology and Biotechnology
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• 제32권5호
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• pp.663-671
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• 2022

The saccharification of cellulose and hemicellulose is essential for utilizing lignocellulosic biomass as a biofuel. While cellulose is composed of glucose only, hemicelluloses are composed of diverse sugars such as xylose, arabinose, glucose, and galactose. Sulfolobus acidocaldarius is a good potential candidate for biofuel production using hemicellulose as this archaeon simultaneously utilizes various sugars. However, S. acidocaldarius has to be manipulated because the enzyme that breaks down hemicellulose is not present in this species. Here, we engineered S. acidocaldarius to utilize xylan as a carbon source by introducing xylanase and β-xylosidase. Heterologous expression of β-xylosidase enhanced the organism's degradability and utilization of xylooligosaccharides (XOS), but the mutant still failed to grow when xylan was provided as a carbon source. S. acidocaldarius exhibited the ability to degrade xylan into XOS when xylanase was introduced, but no further degradation proceeded after this sole reaction. Following cell growth and enzyme reaction, S. acidocaldarius successfully utilized xylan in the synergy between xylanase and β-xylosidase.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2011년도 학술대회 및 정기총회
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• pp.113-116
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• 2011

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2007년도 제48회 학술심포지움 및 추계국제학술대회
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• pp.128.2-128.2
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• 2007

See Full Text

• 한국약용작물학회:학술대회논문집
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• 한국약용작물학회 2012년도 심포지엄 및 춘계학술발표회
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• pp.43-44
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• 2012

• 한국광물학회지
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• 제22권2호
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• pp.81-86
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• 2009

변색 효과를 보이는 6종의 보석들을 대상으로 UV-Vis 분광분석과 Photoluminescence에 의한 발광 및 형광 특성을 조사하였다. 514 nm Ar이온 source로 PL을 측정한 결과 발광 피크의 모양이 다르게 나타났고 같은 천연과 합성 보석에서는 동일한 피크가 나타났다. 이들 발광 및 형광 특성은 보석들의 결정 구조와 관련이 있음을 관찰할 수 있었다. 325 nm He-Cd source에 의한 형광 조사에서는 합성 알렉산드라이트와 합성 칼라체인지 사파이어 그리고 천연 알렉산드라이트에서 강한 형광이 나타났고 이를 PL 피크로 확인하였다.

• Journal of Microbiology and Biotechnology
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• 제14권3호
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• pp.532-539
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• 2004

For efficient lincomycin production from Streptomyces lincolnensis L1245, various vegetable oils, natural nitrogen sources, and surfactants were investigated at the pilot-scale level in the flask. Olive oil as the sole carbon source was the most suitable one for producing lincomycin. When 20 g/lof olive oil was used, the lincomycin concentration and lipase activity reached 1.01 g/land 182 U/ml, respectively, after 5 days of culture. Among the various unsaturated fatty acids, when linolenic acid was used, the cell growth and lincomycin production were markedly decreased. On the other hand, when 0.2 g/l of oleic acid was added to the culture broth, the maximum lincomycin concentration was 1.0 g/l, which was about 1.7-fold higher than that obtained without the addition of oleic acid. Among the various natural nitrogen sources, pharmamedia or soybean meal was the most suitable nitrogen source. In particular, in the case of a mixture of 10 g/l of pharmamedia and soybean meal, 1.5 g/l of lincomycin concentration and 220 U/ml of lipase activity were obtained. When Span 180 was used as the surfactant, lincomycin production, lipase activity, and oil consumption increased. The correlation between the consumption rates of oil and lincomycin production in a culture using olive oil as the sole carbon source was also investigated. The lincomycin production depended on the consumption rate of olive oil. Using these results, fed-batch cultures for comparing the use of olive oil and starch as a conventional carbon source were carried out in a 5-1 fermentor. When olive oil was used as the sole carbon source, 34 g/l of olive oil was consumed after 7 days of culture. The maximum lincomycin concentration was 3.0 g/l, which was about 2.0-fold higher than that of starch medium after 7 days of culture. The product yield was 0.09 gig of consumed carbon source, which was about 3.0-fold higher than that of starch medium after 7 days of culture.

• 대한음성학회지:말소리
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• 제67호
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• pp.135-147
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• 2008

In this paper, we propose a method for source localization in reverberant environments based on an adaptive eigenvalue decomposition (AED) algorithm which directly estimates channel impulse responses from a speaker to microphones. Unfortunately, the AED algorithm may suffer from whitening effects on channels estimated from temporally correlated natural sounds. The proposed method which applies sparse priors to the estimated channels can avoid the temporal whitening and improve the performance of source localization in reverberant environments. Experimental results show the effectiveness of the proposed method.

• Archives of Pharmacal Research
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• 제10권1호
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• pp.67-68
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• 1987

1-eicosanoyl cafferate, mp 109-$110^{\circ}$ was isolated from the underground parts of Echinosophora koreenis together with hexacosanol, mp 75-$110^{\circ}$ 1-Eicosanoyl cafferate was isolated for the first time from plant source.

• Natural Product Sciences
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• 제3권2호
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• pp.106-107
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• 1997

Indole-3-methylethanoate was isolated for the first time form natural source i.e. from the leaves of Camellia sinensis (L.) O. Kuntz and fully characterized by physical and chemical evidence, the biological activity of the compound was studied by wheat coleoptile bioassay which showed growth promoting activity.