• Journal of the Korean Institute of Gas
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• v.26 no.6
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• pp.16-23
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• 2022

In this study, characteristics of effect on hydrogen gas was investigated to hydrogen embrittlement by disk and tensile tests. The developed and commercial alloy was fabricated to a plate material made from an alloy ingot. The prepared materials were processed in the form of a disk to measure rupture pressure by hydrogen and helium gas at a rate of 0.1 to 1,000 bar/min. In the hydrogen pre-charged tensile test, a specimen was hydrogenated using an anode charging method, and the yield strength, ultimate tensile strength, elongation, and reduction in area rate were carried by a strain rate test. Also, the microstructure was observed to the fracture surface of the tensile test specimen. As a result, the developed materials satisfied endurable hydrogen embrittlement, and the fractured surface showed a brittleness fracture surface with a depth of several ㎛, but dimple due to ductile fracture could be observed.

• Korean Journal of Ichthyology
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• v.33 no.4
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• pp.262-272
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• 2021

The egg development and early life history of Tribolodon hakonensis that collected from the Seomjin River were studied. The fertilized eggs of the T. hakonensis were slightly adhesive and separated with a yellow yolk and no oil globule. The size of the eggs was an average of 2.89 mm (2.79~2.96) in diameter. Fifty percents of the embryos were hatched in about 63 hrs after fertilization at water temperature of 20℃. The newly hatched larvae showed average 6.92 mm (6.09~7.60) in total length. At 8 days after hatching, they were 13.75±0.67 mm (n=10) in total length and their yolk sacs were completely absorbed, opening mouth and anus (postflexion larvae stage). At 40 days after hatching, they became juvenile and reached 26.99±1.82 mm (n=10) in total length and all their fin rays were formed. At 137 days after hatching, the young fish were 72.63±10.7 mm (n=10) in total length and their body shape, color and behavior were similar to those of adult fish. The size of eggs and the larva after hatching significantly affected the initial growth among groups of genus Tribolodon, and the hatching time of fertilized eggs and the growth rate of the early life history according to the water temperate were different.

• Journal of Marine Life Science
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• v.3 no.2
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• pp.96-100
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• 2018

Clonorchis sinensis is a main parasite that infects humans by making freshwater fish as an intermediate host in South Korea. There are so many reports about the infestation status of Clonorchis sinensis metacercariae (CsMc) in freshwater fish living in the river, but there are a few studies of fish in the lake. In this study, we examined CsMc in Cyprinid fish sampled from Soyang Lake, Namyang Lake, Andong Lake and Chunchun Lake from 2016 to 2017. Metacercaria of trematodes were found from Hemiculter eigenmanni and Carassius auratus in Namyang Lake, and Zacco platypus and Opsarichthys uncirostris in Soyang Lake. As a result of PCR using Clonorchis sinensis specific primer sets, it was confirmed that the metacercariae from Hemiculter eigenmanni in Namyang Lake was CsMc. This study provides information on CsMc infestation status of Cyprinid fish in four lakes and it is the first report of CsMc infestation in Namyang Lake.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.121-124
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• 2007

Freshwater-adapted maturing chum salmon (Oncorhynchus keta) involuntarily captured by stationary nets in Yang-yang seashore areas were transferred to freshwater in an outdoor raceway tank at Yeongdong Inland Fisheries Research Institute, NFRDI, Yang-yang, Gangwon, Korea and kept over 1 day until the start of the experiments. The freshwater-adapted females were single-injected intraperitoneally with gonadotropin-releasing hormone analogue, (GnRH-a: $70\;{\mu}g/kg$ body weight, BW) alone or combined with a dopamine receptor antagonist, pimozide($700\;{\mu}g/kg$ BW). Although gonadosomatic indices [GSI, (gonad weight/BW)${\times}100$] did not show significant changes in both 2004 and 2005, GSI of GnRH-a-injected fish during the 2005 trial slightly increased on the 5th and 7th days post-injection compared to those of vehicle treated fish. Hepatosomatic indices [HSI, (liver weight/BW)${\times}100$] of fish injected with GnRH-a alone and combined with pimozide decreased significantly on the 7th day post-injection in 2004(P<0.05). In 2005 trials, HSI was significantly reduced in GnRH-a treated fish on the 7th day post-injection (P<0.05). Pimozide-injected fish showed a pattern with increase of GSI and decrease of HSI, without significant differences. Taken together, these results suggest that at least in part hypothalamic hormones and dopamine receptor antagonist may induce sexual maturation in freshwater-adapted maturing chum salmon. It remains to evaluate these preliminary results by further researches.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.12 no.2
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• pp.81-85
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• 2007

Early growth of chum salmon was investigated in terms of rearing pond condition. The number of fingerling showed big differences by rearing pond $1,003,000{\sim}1,865,000$. The fork length of fingerlings ranged from $3.20{\sim}3.78cm$ and body weight ranged $0.34{\sim}0.49g$. Daily temperature of rearing water in January to March was $6{\sim}8^{\circ}C$, which is inadequate for salmon growth. pH was $6.0{\sim}6.3$ in early and mid February, 6.5 in late February and $6.5{\sim}7.0$ in March. Dissolved oxygen concentration was lowest from 8 a.m. to 6 p.m. and increased after 6 p.m. The maximum value was seen from 9 p.m. to 6 a.m. The mortality of fingerlings was 5 times higher in the daytime than at night because of dissolved oxygen. Growth of fingerlings was affected by daily ration, concentration of dissolved oxygen and rearing temperature.

• Journal of the Korean Wood Science and Technology
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• v.40 no.6
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• pp.418-423
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• 2012

In order to develop the end use of cylindrical laminated veneer lumber (LVL) such as wooden crafts, the water proof-bonding strength, the resistance to abrasion and the surface hardness by painting the surface of LVL were investigated. The study results were as follows; The water proof-bonding strength through 5 cyclic test by boiling in water immersion and drying were favorable without delamination of glue line. Then the formulation of glue was resorcinol resin (100) to hardener of paraformaldehyde (5) by mixed weight percentage. The resistance to abrasion was relatively higher at cross section than tangential section. When tangential section of LVL was painted by UV protection oil, the resistance to abrasion was improved. In case of an cross section of LVL, the higher surface hardness appeared at larch core than radiata pine LVL. Also, in case of an tangential section of LVL, the higher surface hardness appeared at glue line than veneer side.

• The Journal of Fisheries Business Administration
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• v.39 no.3
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• pp.111-137
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• 2008

Fisheries resources living in inland have continuously reduced due to over-fishing and development thoughtless for the environment. Inland fisheries that target the fisheries resources have been also confronted by several problems such as insufficiency of inland fisheries management systems, inconsistent fisheries management system, inferior infrastructure of inland fisheries, and decreasing fishermen's real income. These problems have demotivated fishermen who want to focus on fishing and farming activation. Therefore, this paper provides alternatives of reorganization for turning to sound and healthy inland fisheries industries by reviewing Korean inland fisheries management systems. The reorganization should be preferentially granted resource management by water system considering geographical conditions, seed release, and establishment of fisheries order for maintenance of sound and healthy inland fisheries. Also, the reorganization should be moved toward the competitive strengthening of "company unit" for inland fisheries, the nourishment of fisher-oriented fisheries management system, strong relationship among inland fishermen, the systematic management of inland fisheries, the strengthening of guidance service for inland fisheries, the extension of infrastructure related to fisheries production, the development of inland fisheries policy including public people, and the improvement of inland fisheries system and law reflecting various users of inland fisheries.

• Journal of Aquaculture
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• v.10 no.4
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• pp.439-447
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• 1997

A specific disease syndrome, which led to massive mortality on the Korean mandarin fish fingerling (Sinperca scherzeri) at Chongpyong Inland Fisheries Institute was atudied. The causetive agent isolated from the diseased fish was identified as Aeromonas hydrophila on the basis of biochemical and physiological characteristics. Infection experiments in the Korean mandarin fish fingerling, weighting 3-4 g with A. hydrophila were conducted by immersion, oral administration, intramuscular injection, and injection of the soluble extracellular products secreted from it. Motality rate was higher virulence in intramuscular injection group than other experimental groups. In injection group of the soluble extracellular products, all fish treated with high concentration ($8{\times}10^9$ cfu/ml) were repidly killed into 3-6 hrs. There results show that the Korea mandarin fish fingerling has high susceptibility to A. hydrophila.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.379-379
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• 2017

과거에는 하천 범람으로 인한 홍수피해가 많았으나 최근에는 도시화로 인한 불투수면적의 증가로 홍수도달시간의 단축 및 노면수의 배수불량으로 인한 내수 홍수피해가 많아졌다. 이러한 변화는 도시하천의 홍수예보에 밀접한 관련이 있으며 관련된 분석 모형 및 연계방안 또한 매우 중요하게 되었다. 일반적으로 하천에 대한 유출해석 모형으로 HEC-RAS((Hydrologic Engineering Center-River Analysis System)가 주로 사용되고 있으나 현재와 같이 도심지 하천에서는 내배수의 특성을 고려한 SWMM(Storm Water Management Model)을 사용한다. 또는 이 두모형의 연계를 통해 유출해석을 진행하기도 한다. 최근 HEC-RAS와 SWMM모형이 최신 버전을 공개하였다. HEC-RAS의 경우 2016년 9월 5.0.3버전을 출시하며 1D뿐만 아닌 2D의 모의도 가능하도록 기능을 개선하였으며 SWMM의 경우 2016년 09월 07일 5.1.011버젼이 공개되었다. 본 연구에서는 공개된 최신 모형을 도림천 지역에 적용하여 도림천 지역에 적합한 모형 및 연계 방법을 찾아보려 한다. 이를 통해 최적의 도시홍수예보 시스템을 구성하기 위한 모형 및 연계방안의 조사와 가장 합리적인 도시홍수 시스템의 구성방안을 제시하고자 한다.