• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 1998.09a
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• pp.35-45
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• 1998

• Journal of Power Electronics
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• v.7 no.4
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• pp.336-342
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• 2007

This paper presents the development of a fuel cell dynamic simulator using a programmable DC power supply and LabVIEW graphical user interface. The developed simulator closely describes the static and dynamic characteristics of an actual proton exchange membrance fuel cell (PEMFC). The experimental results are provided to verify the operation of the simulator. The developed simulator can be used as a convenient and economic alternative to an actual fuel cell for developing and testing a fuel cell power conditioning system.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.11a
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• pp.69-79
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• 2002

• Microbiology and Biotechnology Letters
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• v.25 no.1
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• pp.37-43
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• 1997

Triphenylmethane was decolorized rapidly by enterbacter cloacae MG 82 at initial reaction time. The spheroplast showed higher activity of triphenylmentane decolorization than that of intact cell suspension. The outer part of the bacterial cell envelope and the peptidoglycan are important for the function of transport barrier of triphenylmethane. In intact cell, decolorization activity was higher at 37$\circ $C than at $\circ $C, indicating that triphenylmethane decolorization is due to the enzyme reaction. Culture filtrate showed no decolorization activity, while cell-free extract appeared high activity of 1.45 units, clearly showing that decolorization activity was due to the cell-free extract. Comparing decolorization activities of cell fractions, it was found that decolorization activity was located at the compartment of cytoplasmic membrane. The enzyme activity was also shown to be Mg$^{++}$-dependent. The optimum pH and temperature of enzyme activity were 7.0 and 50$\circ $C, respectively. The thermostability of this enzyme at 35$\circ $C was kept to 58% for 3 hours.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.574-578
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• 1992

고분자 전해질형 연료전지(PEMFC)는 전해질로서 수소이온 교환 특성을 갖는 폴리머를 사용한 연료전지로서 다른 유형의 연료전지에 비하여 에너지 변환 특성이 우수할 뿐만 아니라 전력밀도 특성이 우수한 유형의 연료전지이다. 전해질 폴리머로서는 Perfluorosulfonate 멤브레인이 사용되고 있으며, 전지의 작동 원리는 인산형 연료전지와 동일하다. 본 총설 논문에서는 PEMFC의 작동 원리 및 기능상의 설명은 지양하고 고전력 밀도가 가능한 이유와 지금까지의 개발 역사 및 향후 개발 방향 등에 대해서 설명하고자 한다.

• Korean Journal of Microbiology
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• v.10 no.1
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• pp.29-34
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• 1972

The present study is of ultra-fine structure of Cryptococcus neoformans by means of electron microscopy and reveals the following : 1) In constrast to the bacteria, the normal Cryptococcus neofrmans contains nuclear enveloped with nuclear menbrane, mitochondria, endoplasmic reticulum, distinct cell wall and cell membrane, vacuoles and storage granules as observed in the eucaryotic cells. 2) In apparent cell walls and cell membrane with the appearance of electron transparent area (ETA) and changes of cell morphology were observed in the ultra-violet ray irradiated cell. 2) In apparent cell walls and cell membrance with the appreance of electron transparent area (ETA) and changes of cell morphology were observed in the ultra-violet ray irradiated cell. 3) Morphology changes and cytoplasmic element abnormality was increased with irradiated time. 4) Increase of electron transparent area was thought to be associated with degradation of cell.

• Microbiology and Biotechnology Letters
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• v.23 no.1
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• pp.31-35
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• 1995

Using the alkalophillic Bacillus sp. SH-8 and its mutant Bacillus sp. SH-8M capable of growing at the neutral pH, the amino acid compositions of the cell wall and cell membrane were studied at varying cultivation pH's. The pattem of protein electrophoresis was also tested. It was elucidated that the amino acids consisting of the cell wall were alanine, glutamic acid, lysine, aspartic acid, and meso-diaminopimelic acid. There was not any significant difference in the amino acid compositqon betweeo`two straqns regardless of the culture pH. As the results of HPLC ssay, glutamic acid and aspartic aciu accounted for more than 50% in the amqno acid composytqon of the cell wall. By the isolatqon of the crude cell membrane and the SDS-PAGE analysis, it was found that there was a considerable difference qn the protein pattern when the straqns were cultured at the neutral pH. In addition, by the two dimensional gel electrophoresis, it was confirmed that there was a difference in the protein patterns between two strains cultivated at the neutral pH medium but no difference at the alkaline medium.

• Microbiology and Biotechnology Letters
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• v.21 no.5
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• pp.414-420
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• 1993

Escherichia coli mrdAts and mrdBts mutants forming spherical cells at 42C, were employed to investigate the possible role of both inner and outer membrance structures in the determination of cell shape of gram-negative cells. Spherical cells, but not rod-shaped wild types, were specifically killed by anionic detergents, such as sarkosyl, sodium dodecylsulfate and sodium deoxycholate. From the spherical intact cells grown overnight at 42C, much more proteins were released by sakosyl.

• Membrane Journal
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• v.12 no.1
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• pp.1-7
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• 2002

Currently, the commercialized cation exchange membranes have the excellent performance and stability, however their costs are very expensive and they are not still optimized for the several application areas. A number of membranenologists are focused to solve the problems on the development of novel membrane to be applicable to each membrane field. The present will deal with the introduction of the existing membrane materials and their performances.

• Journal of Acupuncture Research
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• v.20 no.3
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• pp.45-62
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• 2003

Objective : To examine the effects of Beevenom on the cell proliferation of human breast carcinoma cell line MCF-7, we performed various experiments such as does-dependent effect of Beevenom on cell proliferation and viability, morphological changes, and alterations of apoptosis/cell cycle-regulatory gene products. Methods : Beevenom induced cell viability and proliferation of MCF-7 cells in a concentration-dependent manner. The anti-proliferative effect by Beevenom treatment in MCF-7 cells was associated with morphological changes such as membrance shrinking and cell rounding up. Results : Beevenom induced apoptotic cell death in a concentration-dependent manager, which was associated with degradation of ${\beta}$-catenin, an apoptotic target protein. Beevenom induced the Bax expressions, a pro-apoptotic gene, both in protein and mRNA levels, however, the levels of Bcl-$X_{S/L}$ expression, an anti-apoptotic gene, were down-regulated in Beevenom-treated cells. Western blot analysis and RT-PCT data revealed that the levels of cyclin of B1 protein and cyclin E mRNA were reduced by Beevenom treatment in MCF-7 cells, respectively, where as the expression of tumor suppressor p53 and cyclin dependent kinase inhibitor p21 mRNA were markedly increased in a concentration-dependent fashion. Conclusions : Taken together, these findings suggest that Beevenom induced inhibition of human breast cancer cell proliferation is associated with the induction of apoptotic cell death and Beevenom may have therapeutic potential in human breast cancer.