• Bulletin of the Korean Space Science Society
• /
• 1998.10a
• /
• pp.44.1-44
• /
• 1998

No Abstract.See Full-text

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.291-293
• /
• 2003

A semiconductor switch-based fast hi-polar high voltage pulse generator is proposed in this paper The proposed pulse system is made of a thyristor based-rectifier, DC link capacitor, a push-pull resonant inverter, a high voltage transformer. secondary capacitor, a high voltage IGBT & diode stacks, and a variable capacitor. The proposed system makes hi-polar high voltage sinusoidal waveform using resonance between leakage inductance of the transformer and secondary capacitor and transfers energy to output load at maximum of the secondary capacitor voltage. Compared to previous hi-polar high voltage pulse power supply using nonlinear transmission line, the proposed pulse power system using only semiconductor switches has simple structure and gives high efficiency

• Journal of Microbiology
• /
• v.44 no.6
• /
• pp.694-698
• /
• 2006

Several marine bacterial strains were isolated from Undaria pinnatifida (Miyok in Korean). Sixty-six strains were isolated on R2A agar media at $10^{\circ}C$ and identified by a phylogenetic analysis of the 16S rRNA gene sequences. They were grouped into 10 different sequence types based on the initial sequence analysis of the 5' domain of the gene (approximately 500 bp). Full sequences of 16S rRNA gene, were obtained from one strain in each sequence type and the species-affiliation was determined using phylogenetic and sequence similarity analyses. The results of the analyses indicated that they were closely related to Psychrobacter aquimaris, P. celer, P. nivimaris, P. pulmonis, Psychromonas arctica or Bacillus psychrodurans. These bacteria are marine or psychrotrophic bacteria. Because the sporophytes of U. pinnatifida are cultured on the costal area during winter, the U. pinnatifida-associated bacteria appeared to grow at low temperatures. U. pinnatifida sporophytes can be a good source for the isolation of psychrotrophic bacteria.

• Journal of Astronomy and Space Sciences
• /
• v.37 no.1
• /
• pp.69-75
• /
• 2020

We analyze the observations of temperature and ozone measured by the Microwave Limb Sounder (MLS) during the period of 2005-2016, to investigate the vertical structures of temperature and ozone in the stratosphere and mesosphere during stratospheric sudden warming (SSW). We compute the height profiles of the correlation coefficients between 55 height levels of MLS temperature anomalies and compare them with the results of Whole Atmosphere Community Climate Model simulations for three major SSWs. We also construct the temperature and ozone anomalies for the events to investigate the changes in the temperature and ozone distributions with height. There seems to always be a relatively weak but broad negative correlation between the temperature anomaly at 10 hPa and temperature anomalies over the entire mesosphere during the period before SSW events. However, this pattern gets stronger in the lower mesosphere but becomes a positive correlation in the upper mesosphere and lower thermosphere after the onset of SSW. We also found that the temperatures from the simulations show a similar trend to the observational results but with smaller variations and the transition height from negative to positive correlation in the mesosphere is much lower in the simulation than in the actual observations.

• Animal Systematics, Evolution and Diversity
• /
• v.28 no.2
• /
• pp.84-96
• /
• 2012

Some gorgonians in the families, Primnoidae and Isididae within the suborder Calcaxonia were collected from subtidal zones between depths of 10 and 45 m in the coastal regions of King Sejong Station ($62^{\circ}13'S$, $058^{\circ}47'W$), Korea Polar Research Institute of Korea Ocean Research and Development Institute (KORDI) by SCUBA diving from 2009 to 2011. Three species in the Primnoidae, $Arntzia$ $gracilis$ (Molander, 1929), $Thouarella$ ($Thouarella$) $antarctica$ (Valenciennes, 1846) and $Onogorgia$ $nodosa$ (Molander, 1929), and also one species in the family Isididae, $Tenuisis$ $microspiculata$ (Molander, 1929) are newly recorded to octocorallian fauna in Marian Cove and Potter Cove of King George Island. These four species have been described in detail.

• The Bulletin of The Korean Astronomical Society
• /
• v.24 no.2
• /
• pp.67-67
• /
• 1999

• Ocean and Polar Research
• /
• v.27 no.4
• /
• pp.443-450
• /
• 2005

The ratio of breeding pairs of brown skuas (Catharacta lonnbergi), south polar skuas (C. maccormicki) and mixed species pairs between Barton and Weaver peninsulas remained the same $(X^2-test,\;X^2=0,503,\;df=2,\;p=0.778)$. The nests of skuas were clustered on Barton, whereas they were distributed randomly on the Weaver peninsula. The distance between brown skua nests, and that of mixed species pair nests were longer than those of south polar skua nests. Brown skua nests were distributed along the coast. Whereas, the nests of mixed species pairs and south polar skuas were found more frequently inland (Kruskal-Wallis, $X^2=11.631$, df=2, p<0.005). There was no interspecific difference in the distances between skua nests and Penguin rookery at Barton (Kruskal-Wallis, $X^2=2.153$, df=2, p=0.341) or at King Sejong Station (ANOVA, F=1.483, df=2, p=0.229). In general, skuas prefer lower locales (<125m above sea level) for their nest building sites. Brown skua nests were distributed mainly on the beach, whereas south polar skua were distributed on the predominant periglacial landforms and till areas $(X^2-test,\;X^2=24.988,\;df=8,\;p<0.005)$.

• Mycobiology
• /
• v.37 no.3
• /
• pp.240-242
• /
• 2009

An improved procedure for preparing PCR cloning vectors was developed. This procedure includes the incorporation of adapters to create XcmI restriction enzyme sites in pBluescript II SK(+) vectors, digestion with XcmI followed by further digestion of the small fragment produced by XcmI digestion with additional enzymes, and purification with PCR purification kits. Using this procedure, PCR cloning vectors with high ligation efficiencies and low blue or false-positive colonies were obtained.

• Proceedings of the Korean Society of Plant Biotechnology Conference
• /
• 2005.04a
• /
• pp.153-153
• /
• 2005

• KSBB Journal
• /
• v.30 no.6
• /
• pp.345-349
• /
• 2015

Antifreeze proteins (AFP) inhibit growth and recrystallization of ice, and permit organisms to survive in cold environments. The AFP from an Antarctic bacterium, Flavobacterium frigoris PS1, FfIBP (Flavobacterium frigoris icebinding protein), was produced in E. coli using a cold shock induction system. The culture temperature was shifted from $37^{\circ}C$ to $15^{\circ}C$ and a 20 L culture scale was used. The final weights of dried cell and FfIBP were estimated to be 126 g and 8.4 g, respectively. The thermal hysteresis (TH) activity ($1.53^{\circ}C$) of the produced FfIBP was 3.6-fold higher than that of the LeIBP (Leucosporidium ice-binding protein) produced in Picha. The current study demonstrates that large-scale production of FfIBP was successful and the result could be extended to further application studies using recombinant AFPs.