• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.86-88
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• 2018

The three level(3L) neutral point clamped (NPC) voltage source converter (VSC) topology is widely used for grid interface in high power wind energy due to its superior performance as compared to the two level(2L) VS. However, one of the major drawbacks of this topology is the unequal dispersion of loss and therefore the junction temperature among the power devices. The 3L ANPC topology derived from the NPC topology was proposed to resolve this drawback of unequal loss profile of 3L NPC. The 3L ANPC can work under various switching strategies. In this paper a comparative study of the various switching strategies of 3L ANPC using the recently developed 10kV IGCTs which has the capability to raise the current and voltage rating of the wind turbines is carried out. The comparison is performed using ABB make 10kV IGCT 5SHY17L9000 and PLECs simulations.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.8
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• pp.1308-1314
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• 2018

Objective: Gut health improvements were monitored with respect to growth performance, diarrhea incidence, fecal bacterial population and intestinal morphology of suckling pigs orally supplemented with live Lactobacillus salivarius (L. salivarius) oral suspensions and challenged with $F4^+$ enterotoxigenic Escherichia coli (ETEC). Methods: Two groups of newborn pigs from 18 multiparous sows were randomly designated as non-supplemented (control: n = 114 piglets) and L. salivarius supplemented groups (treatment: n = 87 piglets). Treatment pigs were orally administered with 2 mL of $10^9$ colony-forming unit (CFU)/mL L. salivarius on days 1 to 3, then they were orally administered with 5 mL of $10^9CFU/mL$ L. salivarius on days 4 to 10, while those in control group received an equal amount of phosphate buffered saline solution. On day 24 (2 weeks post supplementation), one pig per replicate of both groups was orally administered with $10^8CFU/mL$ $F4^+$ ETEC, then they were euthanized on day 29 of experiment. Results: Results revealed that pigs in treatment group had a statistically significant increase in average daily gain, body weight and weight gain, and tended to lower diarrhea throughout the study. Numbers of Lactobacillus population in feces of treatment pigs were higher than control pigs, especially on day 10 of study. Numbers of total bacteria in intestinal contents of control pigs were also increased, but not Coliform and Lactobacillus populations. Histological examination revealed statistically significant improvements of villous height and villous/crypt ratio of duodenum, proximal jejunum and distal jejunum parts of treatment pigs compared with controls. Duodenal pH of treatment group was significantly decreased. Conclusion: Oral supplementation of live L. salivarius during the first 10 days of suckling pig promoted growth performance and gut health, reduced diarrhea incidence, increased fecal Lactobacillus populations and improved intestinal morphology.

• Analytical Science and Technology
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• v.18 no.4
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• pp.320-328
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• 2005

The most common five chlorophenols (4-chloro-3-methylphenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, 2,3,4,6-tetrachlorophenol, pentachlorophenol) were determined from the industrial wastewater by GC/MS. The samples were collected from the petrochemical company, textile company and leather making company. The developed analytical method was modified by USEPA Method 3510. The samples were extracted with dichloromethane under pH 2 and pH 5-6, and determined by the GC/MS with SIM mode. There were good linearities (above $R^2=0.9943$) on e ranges of the 0.1 ng/mL~10 ng/mL and 0.5 ng/mL~10 ng/mL, and the limit of detection were between 0.1 ng/mL and 0.5 ng/mL. The absolute recoveries were measured at the concentration of 1, 5, and 10 ng/mL, and the recovery was 71.6~98.9% except for PCP. The relative standard deviation (RSD) was 1.2~14.3% and it gave a good reproducibility for the assay. The bias, which shows the accuracy, was a good although it was a little high values (11.3~22.1%) at the low concentration (1 ng/mL).

• Journal of Ginseng Research
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• v.11 no.2
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• pp.136-144
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• 1987

Biosynthesis of saponins from acetate, mevalonate and squalene using root slices of panax ginseng C.A. Meyer was investigated. The sliced roots (2g) were incubated with the reaction mixture containing 20 M sodium acetate ($500\mu$Ci [U-$^{l4}C$]-acetate),10 mM mevalonate ($25\mu$Ci [2-$^{l4}C$]-mevalonate) or 10 mM swidme ($10\mu$Ci [4,8,12,13,17,21-$^3H$]-squalene) respectively at $30^{\circ}C$ for 72 hours. Biosynthesis of labelled ginseng saponine from [U-l4C]-acetate, [2-$^{l4}C$]-mevalonate and [4,8,12,13,17,21-$^3H$]-squalene was confirmed by autoradiography. Analysis of the products from [U-$^{l4}C$]-acetate by T.L.C. showed that the % radioactivities in panaxadiol, panaxatriol, squalene and mevalonate were found to be 2.1%, 2.7%, 2.6% and 0.2% respectively. Some of the sugars were also highly labelled. Analysis of the products from [2-$^{l4}C$]-mevalonate by T.L.C. showed that squalene was highly labelled and the products from [4,8,12,13,17,21-$^3H$]-squalene showed that panaxadiol, panaxatriol and sterol were highly labelled. From the above results, it was suggested that saponine might be synthesized from acetate via mevalonate-squalene route as expected in ginseng root.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.9
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• pp.847-851
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• 2016

Due to global warming it is estimated that the arctic ocean route will be avaliable and traffic will increase by approximately year 2030. However, most navigation in the arctic is based on the ice breaker captains'orders, there is no exact measurement of convoy speed and distance between ships. So, this research was conducted to find out the minimum safe separation distance and minimum breaking distance via ship controling simulations, and the results are as stated. For breaking distances, for ships that have a lead distance which is 2~4 times the width of the ship and traveling less than 7 knots, crash astern and crash astern & hard rudder showed no significant difference. But ships traveling at 10 knots there was a decrease in breaking distance of 1L, from 3.5L to 2.5L. By analyzing 10 subject ships by crash astern the breaking distance for 5 knots is 0.98L~1.8L, for 8 knots is 1.9L~4.0L. The minimum safe separation distance in narrow sea-ways is 6L, but as the arctic sea-way is only one-way 3L is required. As the result, it is found that in the arctic the safe escort speed is less than 5 knots, if the escort speed is 8knots or more and by using crash astern & hard rudder to break the safe distance should be kept at 3.4L.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.124-128
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• 2005

This studies were carried out to investigate optimal conditions for Lactic acid bacteria growth, which was grown in a batch fermenter. The optimal temperature was $30^{\circ}C$, optimal pH was 6.5 and agitation speed was 100rpm and didn't supply the air. Used media compositions were yeast extract 5g/L, peptone 10g/L, sugar 20g/L, beef extract 10g/L, tween 80 1ml/L, ammonium citrate 2g/L, sodium acetate 5g/L, magnesium sulfate 0.1g/L, manganese sulfate 0.05g/L, dipotassium phosphate 2g/L. These results would be useful for enhancing lactic acid bacteria concentration.

• Journal of Advanced Marine Engineering and Technology
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• v.21 no.4
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• pp.430-436
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• 1997

Time-dependent Flow characteristics of a two-dimensional lid-driven square cavity flow of six high Reynolds numbers, $10^4 2{\times}lO^4., 3{\times}l0^4, 5{\times}lO^4, 7.5{\times}lO^4$ and $10^5$ were investigated. A convection conservative difference scheme based upon SOLA to maintain the nearly 2nd-order spatial accuracy was adopted on irregular grid formation. Irregular grid number is $80{\times}80$ and its minimum size is about 1/400 of the cavity height(H) and its maximum is about 1/53 H. The result shows that at Re= $10^4$, periodic migration of small eddies appearing in corner separation region and its temporal sinusoidal fluctuation are represented. And another critical Reynolds number which shows the commencement of flow randomness emerging from the periodic fluctuation is assumed to be around Re= $1.5{\times}10$. At five higher Reynolds numbers ($2{\times}lO^4., 3{\times}l0^4, 5{\times}lO^4, 7.5{\times}lO^4$ and $10^5$), an organizing structure of four consecutive vortices similar to a Moffat vortex at two lower corners is revealed from time-mean flow patterns.

• YAKHAK HOEJI
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• v.47 no.6
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• pp.450-455
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• 2003

Synthesis of (lR,5S,6S)-6-[(lR)-1-hydroxyethyl] -2-[(3S,5S)-5-(2-ethoxycarbonyl-1-moxy(hydroxy)iminoethyl)pyrrolidine-3-ylthio]-1-methylcarbapen-2-em-3-carboxylic acids (10a,l0b) were described. Methyl(2S,4S)-4-tritylthio-1-(allyloxycarbonyl)pyrrolidine-2-carboxyla late (I) was prepared from trans-4-hydroxy-L-proline with (2S,4R)-abs olute configuration as starting material. (2S,4S)-1-allyloxycarbonyl-2-(2-ethoxycarbonyl-hydroxy(methoxy )iminoethyl)-4-mercapto- pyrrolidines (6,7) were obtained from the tritylthio compound (I). (lR,5S,6S)-6-[(lR)-1-hydroxyethyl]-2-[(3S,5S)-5-(2-ethoxycarbonyl-1-methoxy(hydroxy)imino-ethyl)pyrrolidine-3-ylthio]-1-methylcarbapem-2-em-3-carboxylic acids (10a,10b) were obtained by the coupling reaction with carbapenem diphenylphosphates (8) and pyrrolidine-thiol moiety (6,7). Their in vitro antibacterial activities against both Gram-positive and Gram-negative were tested. Compounds ( 10a,10b) showed potent antibacterial activity except pseudomonas aerusinosa.

• KSBB Journal
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• v.22 no.1
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• pp.1-6
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• 2007

The optimum liquid culture conditions were investigated for cell growth and polysaccharide production from liquid culture of Lentinus edodes. In flask culture, the optimal medium compositions for the polysaccharide production contained glucose 60 g/L, yeast extract 10 g/L, $KH_2PO_4$ 2.0 g/L, and $MgSO_4{\cdot}7H_2O$ 1.0 g/L. The maximum mycelial growth and polysaccharide production were 11.01 g/L and 1.64 g/L, respectively. In bioreactor, through the variation of aeration in order to increase mycelial growth and polysaccharide production, the maximum mycelial growth and polysaccharide production were 55.9 g/L at 8th day and 7.34 g/L at 7th day of cultivation with 1.5 vvm, respectively.

• Journal of Microbiology and Biotechnology
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• v.23 no.5
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• pp.724-730
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• 2013

We investigated the effects of orally administered probiotic bacteria (Lactobacillus species) as allergic immune modulators in ovalbumin (OVA)-sensitized mice. BALB/c mice were intraperitoneally injected with OVA twice at a 2-week interval for allergy sensitization. The mice were then orally administered Lactobacillus casei YIT9029 (L1), L. casei HY7201 (L2), L. brevis HY7401 (L3), or L. plantarum HY20301 (L4) every 2 days for 3 weeks. Total IgE levels significantly decreased in sera of L3-administered mice but increased in the other groups. OVA-specific IgE levels decreased slightly in sera of mice administered L1, L3, and L4 but increased significantly in L2-administered mice. In passive cutaneous anaphylaxis (PCA) using sera from administered mice, only the L3-administered group showed reaction inhibition. High expression of TLR-2 with interferon (IFN)-${\gamma}$ stimulation on peripheral blood mononuclear cells occurred in L3- or L4-administered mice. Th1 cytokines, including IFN-${\gamma}$ and interleukin (IL)-12, increased in splenocytes of L3-administered mice; however, IL-4 decreased in L1- and L4-administered groups; IL-5 decreased in all experimental groups. IL-6 decreased in the L3-administered group; and IL-10 decreased in L1-, L2-, and L3-administered groups. L3 induced antiallergic effects by increasing Th1 cytokines, decreasing Th2 cytokines, and inhibiting the PCA reaction, whereas L2 administration increased allergic effects.