• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.1
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• pp.55-60
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• 2002

For the development of a new creep test technique, the availability of SP-Creep test is discussed for 1Cr-0.5Mo boiler header material. And some results are also compared with those of 2.25Cr- 1Mo steel which widely uses as boiler superheater tube. The results can be summarized as follows. The load exponents(n) obtained by SP-Creep test for 1Cr-0.5Mo steel are decreased with increasing creep temperature and the values are 15.67, 13.89, and 17.13 at 550$^{circ}C$ ,575$^{circ}C$ and 600$^{circ}C$, respectively. The temperature dependence of the load exponent is given by n = 107.19 - 0.1108T. This reason that load exponents show the extensive range of 10∼16 is attributed to the fine carbide such as M$_{23}$C$_{6}$ in lath tempered martensitic structures. At the same creep condition, the secondary creep rate of 1Cr-0.5Mo steel is lower than the 2.25Cr-1Mo steel1 due to the strengthening microstructure composed by normalizing and tempering treatments. Through a SEM observation, it can be summarized that the primary, secondary, and tertiary creep regions of SP-Creep specimen are corresponding to plastic bending, plastic membrane stretching, and plastic instability regions among the deformation behavior of four steps in SP test, respectively.y.

• Applied Biological Chemistry
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• v.42 no.2
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• pp.105-110
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• 1999

Acetobacter sp. were isolated from persimmon vinegar. We studied about conditions of Aloe vinegar fermentation by an isolated strain and inhibitory effect against lipase activity. Strains DS-118 was strictly aerobic, motile, gram negative, non-spore-forming and short rod shaped. It reacted positively in catalase test, was oxidase test negative, was ureas negative, was produced acetic acid from alcohol. On the basis of these results, it was identified as a strain of Acetobacter sp. In the preparation of Aloe vinegar, optimun initial alcohol concentration, acidity, and fermentation temperature were 10%, $3{\sim}4%$ and $25^{\circ}C$, respectively. The major organic acid in Aloe vinegar was acetic acid (12%), but malic acid and ${\delta}-galactronic$ acid were also present in trace. The Aloe vinegar(acidity : 12%) inhibited lipase activity and it's $IC_{50}$ was 43%.

• Journal of Microbiology and Biotechnology
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• v.30 no.11
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• pp.1785-1791
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• 2020

In a previous study, the sequential optimization and regulation of environmental parameters using the PhotoBiobox were demonstrated with high-throughput screening tests. In this study, we estimated changes in the biovolume-based composition of a polyculture built in vitro and composed of three algal strains: Chlorella sp., Scenedesmus sp., and Parachlorella sp. We performed this work using the PhotoBiobox under different temperatures (10-36℃) and light intensities (50-700 μmol m^-2 s^-1) in air and in 5% CO₂. In 5% CO₂, Chlorella sp. exhibited better adaptation to high temperatures than in air conditions. Pearson's correlation analysis showed that the composition of Parachlorella sp. was highly related to temperature whereas Chlorella sp. and Scenedesmus sp. showed negative correlations in both air and 5% CO₂. Furthermore, light intensity slightly affected the composition of Scenedesmus sp., whereas no significant effect was observed in other species. Based on these results, it is speculated that temperature is an important factor in influencing changes in algal polyculture community structure (PCS). These results further confirm that the PhotoBiobox is a convenient and available tool for performance of lab-scale experiments on PCS changes. The application of the PhotoBiobox in PCS studies will provide new insight into polyculture-based ecology.

• The Korean Journal of Pesticide Science
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• v.19 no.1
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• pp.71-79
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• 2015

In order to investigating the effects of antifungal activity of intestinal bacteria obtained from insect, it was identified these bacteria isolated from the gut. In this result, total 49 isolates of intestinal bacteria were identified from 10 kinds of insect species. It was that 4 isolates including Cedecea sp. from Nesidiocoris tenuis, 3 isolates including Enterobacter sp. from Odontotaenius disjunctus, 4 isolates including Acinetobacter sp. from Reticulitermes speratus, 4 isolates including Clavibacter sp. from Riptortus clavatus, 11 isolates including Bacillus sp. from Lema decempunctata, 3 isolates including Enterococcus sp. from Henosepilachna vigintioctopunctata 2 isolates including Staphylococccus sp. from Harmonia axyridis, 5 isolates including Enterobacter asburiae from Popillia mutans, 7 isolates including Aeromonas sp. from Hydrophilus acuminatus, and 7 isolates including Brucella sp. from Anomala octiescostata. In order to investigating antifungal activity against plant-pathogenic fungi, Altanaria solani, Colletotrichum gloeosporioides, Botrytis cinerea, Fusarium oxysporum, Phytophthora capsici, Rhizoctonia solani and Selerotinia sclerotiorum were dual cultured with each 49 gut enterobacteriaceae. As these results showed that many isolates have the antifungal activities including 26 isolates against A. solani, 6 isolates against B. cinerea, 13 isolates against C. gloeosporioides, 11 isolates against F. oxysporum, 17 isolates P. capsici, 2 isolates against R. solani and 2 isolates against S. sclerotiorum. Pseudomonas aeruginosa was showed strong antifungal activity against all of tested plant pathogens. It might be taken a potential for application against plant-pathogenic fungi with useful control agent.

• Korean Journal of Food Science and Technology
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• v.29 no.3
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• pp.581-587
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• 1997

For bifidus fermentation food, gelatinized rice solution was fermented without liquefaction/saccharification by amylolytic Bifidobacterium spp. isolated from Korean. Eighteen amylolytic Bifidobcterium on the starch agar were isolated from 38 Korean and four strains were finally selected as good amylase producers. The most enzyme-producing strain of Bif. sp. FBD-12 secreted extracellular amylase of 0.17 U/mg and intracelluar amylase of 1.8 U/mg. Three strains of Bif. sp. FBD-12, Bif. sp. FBD-16 and Bif. sp. FBD-17 also showed good growth on pH controlled media by HCI/acetic acid to pH 5.0 while Bif. sp. FBD-6 was not so tolerant that viable cell counts reduced to $10^2\;CFU/mL$ times on the media. Initial cell number of $10^6\;CFU/mL$ for those strains reached to $10^9\;CFU/mL$ on the rice medium supplemented with yeast extract (0.2%) and cysteine (0.05%). Ascorbic acid instead of cysteine was added to the medium for improving off-flavour and the best growth was shown at 0.1% addition. Isolated soybean proteins (ISP) of 3% accelerated the growth of the strains. Maximum count of $10^9\;CFU/mL$ reached within 12 hour fermentation on the rice medium with ascorbic acid and isolated soybean protein instead of 32 hours on the cysteine medium, and total acidity increased from 0.5% to 1% on each media. Reducing sugar in the ascorbic acid/ISP cultures generally increased especially 2 mg/mL to 15.5 mg/mL for Bif. sp. FBD-6. From sensory evaluation, the products showed good acceptability so that it suggested possibility of development of bifidus-fermented rice food.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.4
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• pp.327-332
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• 2003

We Isolated strains of Micrococcus sp., Pseudomonas sp., Leuconostoc sp. which have protease activity in the Changran-Jeotgal. These microbes were added in the Changran-Jeotgal for the starters during fermentation to short fermentation period to check PH, VBN, $NH_2-N,$ free amino acids, and sensory evaluation. Microbiological changes were also examined for microorganism-added Changran-Jeotgal and the control. Viable cell counts in the microorganism-added Changran-Jeotgal increased from $7.1\times10^5\;CFU/g\;to\;7.5\times10^8\;CFU/g$ on 15th day, The cell counts in the control increased from $4.1\times10^5\;CFU/g\;to\;8.1\times10^8\;CFU/g$ on 30th day. VBN also increased in both. Increasing rates of $NH_2-N$ and free amino acids in the microorganism-added Changran-Jeotgal were faster than those in the control. Sensory evaluation showed that the microorganism-added Changran-Jeotgal was most favorable on 20th day. These results showed that fermentation period was shortened about 10 days in comparison with the control.

• Korean Journal of Environment and Ecology
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• v.30 no.3
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• pp.369-375
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• 2016

This survey was conducted during March to April 2014 in the main stream and tributaries of Xe Pian and Xe Namnoy in order to investigate fish fauna in the Bolaven Plateau. Fish belonging to twenty eight species and eight families were collected from the main stream and tributaries of Xe Namnoy and Xe Pian during the survey period. Among them, Devario salmonatus, Poropuntius bolovenensis, Annamia sp., Sewellia elongata, Schistura bolavenensis, Schistura sp.1, Schistura sp.2, Schistura sp.3, Schistura sp.4, and Macronathus sp. were endemic species in the Bolaven Plateau, indicating a high prevalence rate of endemic species (35.7%) in the area. Meanwhile, Kottelat (2000, 2013) has been reported that four species of Poropuntius inhabit the Bolaven Plateau. However, the major morphic characteristics of Poropuntius species found in the Bolaven Plateau were mostly overlapped, except for the shape of their mouth. The young fish of Poropuntius (> 70 mm SL) have only generalized mouth while the of adult fish the shape of their mouth have two phenotype (narrow and broad). Therefore, it is assumed that Poropuntius species in the Bolaven Plateau has trophic polymorphism as the same species exhibits two different mouth shapes.

• Food Science and Preservation
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• v.14 no.5
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• pp.545-551
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• 2007

Bacillus sp. SP-KSW3 is an auxothroph bacteria that is being used for starter in fermentation. Physico-chemical characteristics, enzyme activities, ACE inhibitor and antimutagenicity in fermented soybean inoculated with Bacillus sp. SP-KSW3 starter was investigated for the ripening duration of fermentation. Tyrosinase and ACE showed 10% higher activity degree on test field than control. for antimutagenicity using S. enterica serovar Typhimurium TA100 against MNNG and NPD showed 86.24% and 75.63% Similarly, S. enterica serovar Typhimurium TA98 was used against NPD and NQO showed 60.28% and 50.92% respectively. Hydrogen donating ability increased compared to the control having 81.7% and 80.1% respectively. Daidzin of isoflavone in fermented soybean showed higher concentration in control than in the test field. Genistein from two years of ripening test field contained 11.67 mg/kg compared to the test field. The initial test field for daidzin contained 389.96 mg/kg which increased to 453.67 mg/kg after two years and the initial genistein contained 402.68 mg/kg which also increased to 556.86 mg/kg.

• Journal of Life Science
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• v.16 no.1
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• pp.120-125
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• 2006

To isolate and identify histamine degrading bacteria from Kwamegi, bacteria were screened with restriction media containing histamine. Ten strains were selected through morphological and biochemical identification procedure followed by comparison with DNA sequence of 16 rRNA gene. And also, these strains were confirmed by the histamine degrading assay such as turbidity and enzymatic assay. The results of identification are as followings : Ewingella americana B791, Arthrobacter sp. R45S, Halomonas marisflava, Psychrobacter sp. 9B-7, Bacillus sp. LMC 21002, Psychrohacter cibarius BC-220, Bacillus megaterium KL-197 were identified showing homology of $99\%,\;95\%,\;98\%,\;99\%,\;99\%,\;99\%\;and\;98\%$, respectively. Three strains remain unidentified. Arthrobacter sp. R45S, H. marisflava, Bacillus sp. LMG 21002, B. megaterium KL-197 showed histamine degrading activity, whereas, Psychrobacter sp. 9B-7 only showed weak activity. Three unidentified strains also have histamine degrading activity. In contrast, E. american B791 and p. cibarius JG-220 did not show any significant activity of histamine degradation. The strains isolated from this study showed relatively fast growth rate and histamine degrading rate as compared to those from salted mackerel.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3641-3643
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• 2011

Multiconfigurational wavefunctions were adopted to study structural isomers, their isomerization reactions and excited states of $HN_3$. In addition to the known linear isomer, two new structural isomers were found. The three isomers can be classified as sp, $sp^2$ and $sp^3$ hybridized species, respectively. The sp3 hybridized species turned out to be the second most stable. Large reaction barriers among these species prevent thermal isomerizations. A low-lying $^3A'$ exists with a relative energy of 13.5 kcal/mol. Dramatic re-hybridization and bond elongation was found in the first excited $^1A"$.