• Journal of IKEEE
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• v.26 no.2
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• pp.306-312
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• 2022

We investigated electrical properties and deep level traps in 4H-SiC merged PiN Schottky (MPS) diodes with different barrier heights by different PN ratios and metallization annealing temperatures. The barrier heights of MPS diodes were obtained in IV and CV characteristics. The leakage current increased with the lowering barrier height, resulting in 10 times larger current. Additionally, the deep level traps (Z_1/2 and RD_1/2) were revealed by deep level transient spectroscopy (DLTS) measurement in four MPS diodes. Based on DLTS results, the trap energy levels were found to be shallow level by 22~28% with lower barrier height It could confirm the dependence of the defect level and concentration determined by DLTS on the Schottky barrier height and may lead to incorrect results regarding deep level trap parameters with small barrier heights.

• The Korean Journal of Pesticide Science
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• v.14 no.2
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• pp.164-169
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• 2010

Methyl (E,E,Z)-2,4,6-decatrienoate is the aggregation pheromone of brown-winged stink bug Plautia stali (Hemiptera: Pentatomidae). Attractiveness of the pheromone synthesized in Korea was compared with that of synthesized in Japan in the field. A lure filled with hexane was used as a control treatment. Catches in trap baited with Korean pheromone was significantly higher than that baited with Japanese one only in one orchard out of three sweet persimmon orchards in 2008. However there was no difference in trap catches between Korean and Japanese pheromones at three sites in 2009. Gas chromatography analysis showed that the components of both pheromones were not different each other. Monitoring of P. stali seasonal fluctuation using Korean pheromone showed that the bugs were most captured in August, 2008 and in September, 2009.

• Korean Journal of Ecology and Environment
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• v.44 no.3
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• pp.264-271
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• 2011

At the Jangheung multipurpose dam, which is on the Tamjin River, a trapping and trucking operation was established to maintain continuous upstream migration of fish,. To facilitate fish gathering, installation of an effective fishing trap was required. In this study, we evaluated the fish trap, established at the Jangheung dam, using PIT (Passive Integrated Transponder) telemetry. A total of 254 individuals from 15 species were monitored. Among these tagged species, 36 individuals from 6 species (Carassius auratus, C. cuvieri, Zacco temminckii, Z. platypus, Pungtungia herzi, and Pseudobagrus koreanus) were detected; a 14.2% detection rate. C. auratus recorded the highest detection rate of 44.2% while P. herzi was 14.3%. Z. temminckii and Z. platypus showed relatively low detection, 5% and 7.7% respectively. Some of individuals from C. auratus and Z. platypus did not pass through the antenna at the first attempt but were continuously detected on multiple days. There were no statistical differences in body size (total length, standard length and body weight) of individuals that did or did not swim into the trap (Mann-Whitney U test, p>0.05). Fish mainly swam into the trap during outflow of water from the dam (Mann-Whitney U test, p<0.001) and showed a higher detection frequency in daytime than nighttime (Mann-Whitney U test, p<0.001). Thus, for fish movement into the trap, external factors such as outflow from dam and time of day have important roles. Based on detection rate, not all fishes showed upstream migration but represented selective migration. Consequently, the establishment of flexible outflow strategies that take into consideration ecological characteristics of fishes should required for improving the efficiency of fishway.

• Korean journal of applied entomology
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• v.59 no.3
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• pp.217-231
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• 2020

In 2019, the sex pheromones of Spodoptera frugiperda were used to examine moth trapping in cornfields in Gochang, Korea. Four types of traps were prepared, two funnel-types and two delta-types, each baited with 300 or 1000 ㎍ of a two-component (2C) blend of synthetic sex pheromones [100% (Z)-9-tetradecenyl acetate (Z9-14Ac) and 2% (Z)-7-dodecenyl acetate (Z7-12Ac)]. The greatest number of S. frugiperda were captured in the 300 ㎍ funnel-type trap (first catch: August 6). Large numbers of Mythimna loreyi (a non-target) were also caught in the funnel-type traps. Two wing-type traps were baited with 1000 ㎍ of the 2C blend or a four-component (4C) blend [100% (Z)-9-tetradecenyl acetate, 8% (Z)-11-hexadecenyl acetate (Z11-16Ac), 2% (Z)-7-dodecenyl acetate, and 1% (Z)-9-dodecenyl acetate (Z9-12Ac)] and the capture efficiency was assessed. Low numbers of S. frugiperda were captured regardless of the blend, and more M. loreyi were captured using the 4C blend. The two intraspecies groups clustered separately in a phylogenetic tree constructed using partial sequences (1004 bp) of cytochrome c oxidase subunit 1 (CO1). Of the 70 S. frugiperda captured in the pheromone traps, 66 belonged to CO1-RS (CO1 rice-strain) and 4 to CO1-CS (CO1 corn-strain). Twelve consistent single nucleotide polymorphisms (SNPs) were identified in CO1 between the CO1-RS and CO1-CS groups of S. frugiperda. Of the 73 S. frugiperda, 4 had the same SNP pattern as the CO1-CS group (including the corn strain) and 69 had the same SNP pattern as the CO1-RS group (including the rice strain).

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1172-1175
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• 1997

Calcium isotopic ratios are precisely measured by removing isobaric interferences originated from water in the plasma. Liquid Ar cryogenic trap combined with membrane desolvator could eliminate backgrounds at m/z 42 and 44. Slow drift of ICP-MS is corrected by the frequent running of the standards. It is found necessary to separate Ca from the sample matrix using Ca oxalate precipitation technique. Currently, the RSD is 0.5-1.0% for 2 minutes of measurement but is expected to be improved if the measurement time is increased. The technique was applied to 42Ca enriched baby fecal samples and successfully determined 42Ca/44Ca ratio changes.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.363-367
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• 2021

This study was conducted to investigate the EAG (electroantennogram) response of Spodoptera frugiperda male to sex pheromone compounds and whether or not S. frugiperda male adults would undergo double mating. The EAG response of S. frugiperda male adult to Z9-14:Ac increased in a dose-dependent as the dose increased. Among the 7 sex pheromone components investigated, male EAG recording was the highest to Z9-14:Ac. The EAG response of S. frugiperda male adult to the mixed sex pheromone component was greater than that to the single component. Male adults of S. frugiperda were capable of double mating under laboratory condition, and the secondary mating rate increased to 72.2% compared to the 58.3% of primary mating rate. The EAG response of mated S. frugiperda male adult was not different from that of unmated S. frugiperda male. In the net house test with sex pheromone lure, mated male adults were not captured during the test period. Also, strangely, unmated male adults were not captured even in a trap equipped with virgin female adults, although the antennae of mated male adult were responded to the sex pheromone component in the laboratory. Probably, it is thought that the mated male adults may not have been caught in the trap be due to flight ability which has been decreased after mating. The field attractiveness of S. frugiperda male adults to sex pheromones remains to be further elucidated.

• Proceedings of the Korean Society of Food Hygiene and Safety Conference
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• 2001.10a
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• pp.140-140
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• 2001

A sensitive analytical method based on gas chromatograpy-mass spectrometry with a selected ion monitoring (GC/MS-SIM) with the purge-and-trap concentration and with headspace method (in limited applications) was developed for determining of epichlorohydrin in canned beverages coated with epoxy resin. The calibration curve in the range of $0.5\sim50ng$ had correlation coefficient greater than 0.998 and a detection limit of $0.l\mug/L$ was obtained using a sample volume of 20ml. The predominant ions of epichlorohydrin produced in MSD using electron ionization(EI) were m/z 57 ([M-CI]+) and 62/64 $([M-CH_2O]+)$. In survey of epichlorohydrin in thirty commercial canned beverage samples, none of them was detected.

• BMB Reports
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• v.43 no.12
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• pp.789-794
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• 2010

A novel gene, designated mgt-6, containing four splicing variants, was isolated from a gene trap clone library of C3H/10T1/2 cells transfected with retroviral promoterless gene-trap vector, ROSAFARY. The transcript variants were differentially expressed in murine tissues and cell lines and differentially responded to diverse stimuli including TGF-${\beta}1$ and mitogen-activated protein kinase (MAPK) inhibitors. The mgt-6 gene encoded a protein of 37 or 11 amino acid residuals with cytoplasmic distribution. However, when C3H/10T1/2 cells were treated with 5-azacytidine, the protein translocated into cell nucleus as indicated by fused LacZ or C-terminally tagged EGFP. Our preliminary results suggest that further study on the role of mgt-6 gene in cell transformation and differentiation may be of significance.

• Korean journal of applied entomology
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• v.40 no.3
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• pp.219-226
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• 2001

To identity the composition and ratio of the sex pheromone in the asiatic leafroller, Archippus breviplicanus (Walsingham), which is a major pest on apple leaves, and to develop a monitoring system using this sex pheromone, abdominal tips of their virgin female during the calling period were extracted and analysed. The GC/GC-MS analysis revealed the following three compounds; (E)11-tetradecenyl acetate (E11-14: Ac), (Z)11-tetradecenyl acetate (Z11-14: Ac), and tetradecyl acetate(14: Ac) with the ratio of 56:22:22. Electroantennogram (EAG) assay was also conducted to examine biological activity of the components. The three components evoked significantly higher responses than hexane or air but there was no significant differences between the mixtures made by components. Field trapping experiments for determining the optimum blend, seasonal fluctuation and the optimum amount for male attracting were carried out over 4 years from 1997 to 2000. Although male moths were attracted to 8:2 and 7:3 between E11-14: Ac and Z11-14: Ac, their 7:3 blend was found to be the most effective. Archippus breviplicanus appears to occur three times a year in Korea. The optimum amount for monitoring was found to be 1mg per trap. 14: Ac, the third component, did not show synergistic effect on male moth attraction.

• Korean journal of applied entomology
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• v.49 no.2
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• pp.123-127
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• 2010

Attractiveness of different amounts of methyl (E,E,Z)-2,4,6-decatrienoate, the aggregation pheromone of brown-winged stink bug, Plautia stali (Hemiptera: Pentatomidae), was tested using different kinds of dispensers. A lure filled with hexane was used as a control treatment. There were no differences in the attractiveness of the pheromone to P. stali and Halyomorpha halys among dispensers (polyethylene-vial, rubber septum, and polyethylene tube). Traps baited with 7, 20, 40, 50, and 60 mg of pheromone were tested for their attractiveness. For females, the 40 mg trap attracted highest number of P. stali, even though there were no significant differences among pheromone amounts. For males, the 40 and 50 mg traps attracted significantly more bugs than the 7, 20, and 60 mg traps and the control traps. Based on these results, the pheromone dispenser impregnated with 40 mg of pheromone will be practical in monitoring P. stali in the field.