• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.431-438
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• 2000

Properties of acid tolerance of an adipic acid-resistant mutant, Leuconostoc paramesenteroides (ANaP100) were studied and compared with those of its paired wild type of Leu. paramesenteroides (LPw). The value of protons permeability of LPw after an acid shock at pH 5.0 was 4.3 min, while the value of ANaP100 was 4.8 min at the same pH. The maximal specific activities of ATPase of LPw and ANaP100 were 0.59 unit/mg protein and 0.63 unit/mg protein at pH 6.0, respectively. The release of magnesium ion from the mutant strain was about 27.3% at pH 4 after 2 hrs, while the wild strain was about 52.2% under the same conditions. The contents of $C_{19:0,cyclo}$ and $C_{18:1}$ in a membrane fatty acid of ANaP100 and LPw were higher and lower, respectively, than that of LPw. These results indicated that acid tolerance of ANaP100 was improved in comparison with that of its wild type, LPw.

• Microbiology and Biotechnology Letters
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• v.28 no.2
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• pp.63-70
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• 2000

To determine an increased acid tolerance of an adipic acid-resistant mutant Leuconostoc mesenteroides(ANaM100) developed for use as a Kimchi starter, proton permeability of cytoplasm, activities of H+-ATPase, Mg++ release and fatty acid composition of cytoplasmic membranes of strain ANaM100 were studied and compared with those of its wild type (LMw). The value of protons permeability of LMw after an acid shock at pH 5.0 was 5.4 min., while the value of ANaM100 cells was 8.4 min. at the same pH. The pH of maximal specific activ-ities of ATPase originated from the LMw and ANaM100 were 0.87 unit/mg protein at pH 6.0 and 0.92 unit/mg pro-tein at pH 5.5, respectively. The release of magnesium ion from ANaM100 was observed about 12.8% at pH 4 after 2 hours, while the wild strains of LMw released Mg++ about 27.6% under the same conditions. The content of C19:0,cyclo and C18:1 in a membrane fatty acid of ANaM100 was higher and lower, respectively than that of LMw. These results indicated that acid tolerance of adipic acid-resistant strain, ANaM100 was significantly improved in comparison with that of its wild type, LMw. In addition, the strain ANaM100 was adipic resistance based on the result of growth of the strain in comparison with that of strain LMw in a broth containing adipic acid.

• Korean Journal of Materials Research
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• v.14 no.11
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• pp.775-779
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• 2004

For improvement of heat dissipation performance, heat analysis is conducted on the newly designed heat sinks under two convection conditions by using computational fluid dynamics(CFD). Three types of heat sink, plate, wave and top vented wave, are used, and convection conditions are the variations of gravity direction at natural convection and of fan location at forced convection. The results of analysis showed that the heat resistances of top vented wave heat sink were $0.17^{\circ}C$/W(forced convection) and $0.48^{\circ}C$/W(natural convection). In the case of natural convection, gravity direction affected heat flow change, and protection against heat performance was superior in case of z-axis gravity direction. Under the forced convection, all the heat sinks revealed superior thermal characteristics in the fan position of z-axis rather than y-axis. In this study, it was observed that the top vented wave type heat sink showed the best ability of heat radiation comparing with the others.

• Journal of the Korean Geophysical Society
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• v.4 no.4
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• pp.251-256
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• 2001

Korean natura1 zeolite with fe1dspar and illite as impurities was purified by an air c1assification method. X-ray powder diffraction ana1yses showed that the air c1assification effectively separated zeolite and impurities, and reduce the amount of impurity of the natura1 zeolite. The zeolite with air c1assification was treated with 1N NaOH solutions at temperatures at 100, 150, 200 ℃ for 17hours. The obtained hydrotherma1 treatment of phase change to philli1site and ana1cime from mordenite and clinopti10lite.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.17 no.6
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• pp.557-565
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• 1984

The year-to-year fluctuations of seasonal variation of sea surface temperatures (SST) in the Korea Strait are studied based on monthly SST data for more than 50 years at Mitsushima ana Okinoshima in the strait. The frequency distribution of SST has two peaks at temperatures below and above the multi-year average, but that of SST anomalies has only one peak at the zero anomaly. More than $95\%$ of the anomalies are in the range of ${\pm}2^{\circ}C$. The harmonic constansts of seasonal SST variation vary from year to year. The standard deviations of annual means, annual amplitudes, ana semi-annual amplitudes are less than $1^{\circ}C$, and those of the annual ana semi-annual phases are about $5^{\circ}$ and less than $50^{\circ}$, respectively. The SST in the Korea Strait have a tendency to decrease their amplitudes as the annual means increase. Physical mechanisms responsible for the analyzed results are discussed in this paper.

• Journal of Environmental Science International
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• v.32 no.5
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• pp.315-328
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• 2023

Cyanobacteria have been used as pollution indicator species in freshwater ecosystems, and identifying their fluctuations can be an important part about management of surface waters globally. Cyanotoxins produced by cyanobacteria are directly or indirectly a threat to human and environmental health. In order to confirm the potential risk of these cyanotoxins, the fluctuations of phytoplankton and phylogenetic analysis of cyanotoxin synthetase genes were conducted at each point in the Yeongsan River water system in Gwangju from November 2021 to October 2022. Diatoms which grow well in winter were dominant at 99.4 ~ 99.5%, and diatoms and green algae were dominant from the spring to autumn when the water temperature rises. Stephanodiscus spp. were dominant at 92.7 to 97.5 % at all sites in the winter, and Aulacoseira spp., which grow in warm water temperatures, were dominant in summer and autumn. Microcystis aeruginosa was dominant at 25.2% in summer only at site 5. mcyB and anaC have been detected as cyanotoxin synthetase genes. The phylogenetic tree of anaC could be divided into two groups (Group 1 & Group 2). Group 1 contained Aphanizomenon sp. and Cuspidothrix issatschenkoi. It is combined with Aphanizomenon sp. and Cuspidothrix issatschenkoi, which are known to produce cyanotoxins.

• Bulletin of the Korean Chemical Society
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• v.24 no.12
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• pp.1841-1842
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• 2003

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.317-322
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• 2000

This study examined the effect of nitrogen$(N_2)$ gas packing and ${\gamma}-oryzanol$ treatment on the shelf life of Yukwa(Korean traditional snack). Yukwa were stored with $N_2$ gas packing(AN), $N_2$ gas packing with ${\gamma}-oryzanol$ treatment(ANA), and PE film packing with air(PE) for 20 days at $60^{\circ}C$. They were evaluated by POV, AV, conjugated diene, hexanal, color and sensory characteristics. The POV, AV and conjugated diene content increased abruptly in PE and AN, but increased slowly in ANA with prolonged storage. Higher sensory scores for Yukwa were found in ANA as compared to those in PE and AN. Hexanal content, yellowness and redness in AN were higher than those in ANA and PE. The moisture content, which is supposed to be related with browning of Yukwa, was 3 times higher in AN than that in PE. Oxygen content of each Yukwa pack, even in $N_2$ gas packing, increased remarkably as storage period increased because their highly porous, fragile and syrup-coated structure resulted in incomplete degassing before $N_2$ gas was flushed into package. Consequently, $N_2$ gas packing was inefficient, but $N_2$ gas packing combined with antioxidant(such as ${\gamma}-oryzanol$) treatment was effective for the extension of shelf life of Yukwa.

• Journal of the Korean Vacuum Society
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• v.3 no.1
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• pp.71-76
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• 1994

The electrical characteristics of the capacitor dielectric films of amorphous silicon-nit-ride-oxide(ANO) structures are compared with the capacitor dielectric films of oxide-nitride-oxide (ONO) structrues The electrical characteristics of ONO and ANO films were evaluated by high frequency(1 MHz) C-V high frequency C-V after constant voltage stree I-V TDDB and refresh time measurements. ANO films shows good electrical characteristics such as higher total charge to breakdown storage capacitance and longer refresh time than ONO films. Also it makes little difference that leakage current and flat band voltage shyift(ΔVfb)of ANO ana ONO films.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.91-96
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• 2005

In this letter, we proposed a novel DGS (Defected Ground Structure) microstrip resonator. The proposed DGS resonator has the resonant and anti-resonant characteristic that is very similar to those of a SAW resonator or a FBAR. In order to confirm the validity of the proposed resonator, we designed and implemented bandpass fitters by using series ana parallel resonators.