• Title/Summary/Keyword: 동해 순환

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Spatio-temporal Fluctuation of Phytoplankton Size Fractionation in the Uljin Marine Ranching Area (UMRA), East Sea of Korea (동해 울진 바다목장해역의 크기별 식물플랑크톤 생물량의 시·공간적 분포 특성)

  • Yoon, Yang Ho
    • Korean Journal of Environmental Biology
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    • v.34 no.3
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    • pp.151-160
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    • 2016
  • To understand size fractioned chlorophyll a and material cycles of coastal ecosystem in Uljin marine ranching area (JMRA) of East Sea, 4 times of survey were conducted from April to November 2008. Picoplankton, nanoplankton and netplankton in the surface of UMRA fluctuated with an annual mean of $0.26{\mu}g\;L^{-1}$ between the lowest value of $0.03{\mu}g\;L^{-1}$ and the highest value of $0.87{\mu}g\;L^{-1}$, annual mean $1.32{\mu}g\;L^{-1}$ between $0.11{\mu}g\;L^{-1}$ and $5.60{\mu}g\;L^{-1}$, annual mean $0.45{\mu}g\;L^{-1}$ between no detected (nd) and $4.68{\mu}g\;L^{-1}$, respectively. And the relative ratio of picoplankton, nanoplankton and netplanktons on the phytoplankton biomass was on annual average 12.9%, 65.0% and 22.1%, respectively. The 10 m layer was similar to the surface. The relative ratio of pico- and nano-plankton was higher throughout the year. That is, the material cycle of UMRA consists of a microbial food web rather than traditional food chain at a lower trophic levels. Primary production is deemed to have a higher possibility of being adjusted by top-down dynamics, such as micro-zooplankton grazing pressure rather than nutrients supply.

The Effect of Wind Stress in the Southwestern Coastal Waters of the Japan Sea (동해 연안역 해수순환에 대한 바람응력 효과)

  • CHANG Sun-Duck;KIM Jong-Kyu
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.26 no.6
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    • pp.538-548
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    • 1993
  • In order to estimate the influence of wind stress in the southwestern coastal waters of the Japan Sea, the wind stress was estimated from the shipboard wind data of the Fisheries Research and Development Agency along the serial observation lines and Buoy No. 6 of the Japan Meteorological Agency. 5,100 wind data are used to construct a data set of monthly mean wind stress during 10 years from 1978 to 1987. The negative values of the mean zonal wind stress curl at Ulleung Basin in the study area seem to be responsible for the formation of the warm core. The volume transport of the East Korea Warm Current are estimated quantitatively by the variations of the Ekman transport associated with the reversing direction of the monsoon. And the distribution of the warm core is explained by the simple three layer model.

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A Review of Ocean Circulation of the East/Japan Sea (한국 동해 해수순환의 개략적 고찰)

  • 김종규
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.103-107
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    • 2001
  • The major studies of an ocean circulation of the East/Japan Sea related to evaluate the feasibility and utilization of deep ocean water are reviewed. The major feature of surface current system of the East/Japan Sea is an inflow of the Tsushima Warm Current through the Korea/Tsushima Strait and the outflow through the Tsugaru and Soya Straits. The Tsushima Warm Current has been known to split into two or three branches in the southern region of the East/Japan Sea. In the cold water region of the East/Japan Sea, the North Korean Cold Current turns to the east near 39$^{\circ}$N after meeting the East Korean Warm Current, then flows eastward. The degree of penetration depends on the strength of the positive wind stress curl, according to the ventilation theory. Various current meter moorings indicate strong and oscillatory deep currents in various parts of the basin. According to some numerical experiments, these currents may be induced by pressure-topography or eddy-topography interaction. However, more investigations are needed to explain clearly the presence of these strong bottom currents. This study concludes the importance of topographical coupling, isopycnal outcropping, different wind forcing and the branching of the Tsushima Warm Current on the circulation of the East/Japan Sea.

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Characteristic of Spatio-temporal Variability Using Hydrological Cycle and Earthquake Catalog in Korea (수문순환과 지진자료를 활용한 지진발생의 시공간적 변동 특성)

  • Jang, Suk Hwan;Oh, Kyoung Doo;Lee, Jae-kyoung;Lee, Han Yong
    • Proceedings of the Korea Water Resources Association Conference
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    • 2018.05a
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    • pp.433-433
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    • 2018
  • 한국은 지진에 대한 관심이 낮았으나, 2016년 09월 12일 경상북도 경주에서 가장 큰 규모인 5.8의 지진이 발생하였으며, 강력한 지진이 발생할 수 있다는 경고가 이어지고 있다. 지진과 관련된 정확한 원인 분석과 정량적인 평가가 체계적으로 이루어지지 않고 있어, 규모와 빈도, 위험지역 분석 등 정밀한 평가와 예방대책을 마련해야 한다. 정량적인 지진 발생 분석을 위해 본 연구에서는 지진 발생과 지하수와 같은 수문기상학적인 인자에 의해 영향을 받는다는 가설을 세우고 지하수의 변동 패턴과 지진의 발생 패턴의 유사점을 추정하였다. 이를 위해 지진자료의 통계적인 특성을 분석하였다. 그리고 지질특성이나 지각 판 운동 외에도 수문순환이 영향을 미치는지 확인하기 위해 육지와 바다에서 발생한 지진으로 구분하여 지진발생횟수와 에너지를 분석하였다. 분석결과, 육지와 바다로 구분했을 때 바다에서 더 많은 지진이 일어났다. 또한 Wilcoxon rank-sum test 비모수 추정기법을 통하여 분석한 결과 서로 다른 성질을 보여 따로 분석하였다. 그 결과, 동해와 남해, 서해와 동해가 같은 성질을 보이는 것으로 분석되었다. 그리고 육지는 8월부터 이듬해 7월까지 지진발생의 한 주기를 이룰 가능성을 보였다. 그러나 바다는 육지와 정반대로 2월부터 7월까지 많은 지진 에너지가 발생하고 있으며, 1월까지는 에너지 수준이 상대적으로 낮은 것으로 분석되었다. 이와 같이 지하수가 육지에서 바다까지 유동하는 시간으로 인해 6개월의 시간지연이 발생하는 것으로 판단된다.

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Norwood Procedure on Beating Heart (심장 박동을 유지하면서 시행한 Norwood 술식)

  • 곽재건;최창휴;김진현;정요천;오세진;이정렬;김용진;노준량;김웅한
    • Journal of Chest Surgery
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    • v.37 no.9
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    • pp.793-795
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    • 2004
  • Modified Norwood procedure with maintaining cardiac beat was done in a 30-day-old neonate. Procedure was done with regional perfusion of innominate and coronary artery. Postoperative course was uneventful. Second-stage operation (bi-directional cavopulmonary shunt) was done 4 months later. The diameter of ascending aorta was more than 5 mm, Norwood procedure can be done in beating hearts.

Strength Development and Freeze-Thaw Resistance of Concrete Incorporating High Volume Blast-Furnace Slag Subjected to Initial Frost Damage (초기동해를 받은 고로슬래그 다량 혼입 콘크리트의 강도발현 및 동결융해 저항성)

  • Koh, Kyung-Taek;Ryu, Gum-Sung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.3
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    • pp.79-87
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    • 2011
  • Concrete incorporating high volume blast-furnace slag placed in cold weather regions might be in danger of initial frost damage because dependently on the mix proportions, the setting and the hardening would be remarkably delayed. Therefore, this study investigated to effect of the degree of frost on the strength development and the resistance to freezing and thawing of the concrete incorporating blast-furnace slag when being subjected to freeze at early age. As the experimental results, the concrete incorporating blast-furnace slag attacked by initial frost damage showed the remarkable reduction of both the compressive strength development and the resistance to freezing and thawing. Especially, the resistance to freezing-thawing of the concrete incorporating high volume blast-furnace slag became much lower than that of the normal concrete.

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