• Journal of the Korean Vacuum Society
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• v.7 no.2
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• pp.94-103
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• 1998

We investigated a bias effect for diamond films deposited by a HFCVD(Hot Filament Chemical Vapor Deposition) method using a methane-hydrogen gas mixture. During deposition total chamber pressure, methane concentration, filament temperature and substrate temperature was 20 torr, 1.0%, $2100^{\circ}C$ and $980^{\circ}C$ respectively. Also DC bias was applied during both the nucleation stage and the growth stage systematically. We found that negative bias enhanced the nucleation density at the nucleation stage, but it made a bad influence on the morpholohy of films at the growth stage. Positive bias enhanced the growth rate and resulted in a good morpholohy of films. Therefore we concluded that it was effective to apply the negative bias during the nucleation stage and then to switch into the positive bias during the growth stage in the fabrication of diamond films.

• Korean Journal of Microbiology
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• v.29 no.5
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• pp.314-318
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• 1991

We investigated the effect of Triton X-100 on the growth and morphology of Trichoderma koningii by comparing various parameters representing the frowth of mold in the presence or absence of Triton X-100. The specific growth rate and doubling time of T. koningii were not affected by the addition of 0.05% Triton X-100 in batch culture. However, in the presence of Triton X-100, cultures reached its stationary phase earlier and showed reduced level in total yield of biomass. The addition of Triton X-100 into solid medium also resulted in decrease in the colony radial growth rate and this response was correlated with the formation of mycelia which showed increase in branching and septation in the presence of Triton X-100.

• ALGAE
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• v.24 no.2
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• pp.79-83
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• 2009

Recently deschbed new species, Cladosiphon umezakii Ajisaka (Ectocarpales,Phaeophyceae) is reported in Korea based on morphology and plastid rbcL sequences. Cladosiphon umezakii occurred on low intertidal to subtidal zone along the south and southeast coasts in Korea. Thalli are gold to dark brown, ercct, cylindrical, irregularly branched,and very mucoid. Unitocular zoidangium is developed at the base uf assimilatory filaments. Assimilatory filaments are very long. Eight specimens of the pecies collected from Korea clustered with those of C. umezakii in Japan in rbcL tree. The pecies showed a sister relationship with C. okamuranus. The occurrence of this warm water species is thought an example of northward migration of marine algae caused by global warming. Because C. umezakii is of the economica! importance of the genus as foods and medidnes, the study on mass culture of the species is necessary in korea.