• Korean Journal of Fisheries and Aquatic Sciences
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• v.3 no.4
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• pp.213-218
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• 1970

Many investigations have been made on V. parahaemolyticus but to the author's knowledge a report on V. parahaemolyticus found in Korean coastal water has not yet been published. The authors have investigated distribution of V. parahaemolyticus in fish, shellfish, mud, crustacea, sea water and cephalopoda in order to determine the possible origins of food poisoning in Korea. The results are summarized as follows: 1. Fifty six of V. parahaemolyticus were isolated from 517 samples obtained from mud, sea water, fish, crustacea and cephalopoda. 2. The distribution of V. parahaemolyticus isolated from the samples was: 6 strains from mud samples, 7 strains from 44 sea water samples, 28 strains from 241 fish samples, 1 strain from 50 crustacea samples and 2 strains from 34 cephalopoda samples. 3. The strains isolated in the Mokpo area were 7 strains from 48 samples and those isolated in the Pohang area were 2 strains from 46 samples. The number of strains in the Mokpo area was the highest among the strains and the number of strains in the Pohang area was the lowest.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.05a
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• pp.269-272
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• 2006

유기물 증가에 미치는 환경인자를 중심으로 그 수평분포 특성, 원인, 주요오염원의 영향권에 대하여 검토하기 위해 표층 해수와 표층 퇴적물을 조사하였으며, 그 결과를 요약하면 다음과 같다. 유기물변동에 영향을 미치는 인자에 대한 주요 오염원은 크게 섬진강과 동천 등의 담수, 광양시 생활하수, 여수산업단지로 크게 나누어볼 수 있었다. 해수와 퇴적물의 환경인자에 대한 수평분포 특성과 해수의 흐름 등을 고려하여 이들 주요 오염원의 영향권을 구분한 결과, (I) 섬진강 담수의 영향을 많이 받는 해역, (II) 광양시와 동천의 영향이 큰 해역, (III) 여수 산업단지의 영향을 많이 받는 해역으로 나누어졌다. 그리고, 오염원의 영향권별 수질환경인자의 특성으로는 섬진강 담수의 영향을 많이 받는 해역은 낮은 염분, 높은 농도의 $NO_3$-N과 $SiO_2$-Si, 담수와 생활하수의 영향이 큰 해역은 낮은 염분, 높은 농도의 $NO_3$-N, $NH_4$-N, $SiO_2$-Si, 여수 산업단지의 영향을 많이 받는 해역은 표층해수의 경우 높은 수온, 높은 농도의 $NH_4$-N과 $PO_4$-P, 퇴적물의 경우 높은 농도의 $NH_4$-N, $PO_4$-P, $SiO_2$-Si로 특징지울 수 있을 것으로 보인다.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.119-119
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• 2017

기후 온난화로 인하여 빙하의 해빙과 해수의 팽창으로 해수면의 상승 속도는 나날이 증가하고 있다. 우리나라는 2.48mm/yr로 상승하고 있으며, 특히 남해는 2.89mm/yr로 가장 크게 상승하고 있다. 해수면의 상승과 더불어 해수침투 영역 확장을 방지할 수 있는 지하수위 또한 낮아지고 있어 해수침투에 대한 피해를 점차 늘어나고 있다. 해수침투로 인한 피해는 연안지역에서부터 시작하여 점점 영역을 넓혀가고 있다. 해수침투 피해는 직접적으로 토지의 염수화로 지하수의 오염, 농작물의 염수 피해, 주변 생태계의 교란 등으로 나타나고 한 번 염수화가 진행된 지역을 되돌리는 것은 많은 노력과 재화가 들어가게 된다. 이를 방지하기 위해서 많은 연구가 진행되고 있다. 해수침투 범위가 증가하는 것이 해수면의 상승도 큰 영향을 미치지만, 해수침투 쐐기를 구성하는 담수 지하수위가 낮아지면 더욱 가속화된다. 이에 본 연구에서는 남해안의 여수지역을 SEAWAT으로 구성하여, 현재의 상황을 나타내고 지하수위, 해수면, 지하수 이용량, 함양량 등을 대상으로 선형적인 상승 혹은 하강으로 미래의 상황을 나타내었다. 적용된 시나리오에 지하수위 관리 방안을 적용하여 해수침투 영역 저감 효과에 대해서 분석하였다. 지하수위 관리 방안으로는 지하수위 하강 시기에 지하수 이용량 규제, 도심지에서 LID(Low Impact Development) 시설물 중 침투 증진 시설 보강 등을 이용하였으며, 각각의 시나리오를 통해 해수침투 영역 저감 효과 분석을 실시하였다. 지하수위의 관리는 해수침투에 대한 피해 방지와 더불어 지속가능한 지하수 이용을 위한 정책을 마련하기 위한 기초자료로 활용할 수 있을 것으로 보여진다.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.3
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• pp.321-328
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• 2022

The current development tend of the gun propellants that they should have low sensitivity and high energy. We studied a nitrocellulose based propellant composition that replaced sensitive NG with RDX and DEGDN which high energy and low sensitivity. The important factors in the design of the gun propellant were impetus and flame temperature. NC-based propellant containing RDX showed similar impetus but low flame temperature compared to KM30A1, a triple-based propellant. The developed propellant composition didn't show any abnormal combustion reaction and the characteristics of ballistic resistance were also confirmed.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.3
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• pp.428-435
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• 2024

The important factors in the design of the gun propellant are impetus, flame temperature and pressure. In this paper, we considered a nitrocellulose based propellant composition that replaced sensitive NG(Nitroglycerin) with RDX(Cyclotrimethylenetrinitramine) and DEGDN(Diethylene glycol dinitrate) which high energy and low sensitivity. Particle size and content of RDX are the two main factors that affect the burning stability of RDX-based propellants. Among them, the characteristics of the propellant according to the particle size of RDX were confirmed. The relative combustion rate(R.Q., Relative Quickness) of the propellant changed according to the RDX particle size, and internal ballistics of properties of propellant were also varied. The particle size of RDX can be confirmed as a major factor in the combustion and internal ballistics characteristics of the propellant.

• Journal of Korea Water Resources Association
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• v.41 no.1
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• pp.65-74
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• 2008

The small and medium sized dams have the fill dam type of a lot of occasions, which are often weak in cases of major floods. For this reason, although a countermeasure is in great need, due to the importance of the facilities and financial situations, no direct safety measures have been taken. In this study, in order to minimize construction expenditure for practical safety measures in cases of major floods, the overflow section of spillway has been analyzed focusing on how the overflow capacity will increase in the case of partially rebuilding a part of the overflow section of spillway favorable for hydraulic conditions. The Labyrinth weir and movable weir was chosen for reconstruction models of the overflow section. Moreover, for analyzing the after-effects of the reconstruction, a small scale dam was temporarily chosen for various experiments such as the hydraulic model testing and the three dimension numerical evaluation through the use of Flow-3D.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.5
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• pp.589-598
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• 1995

Filtering rates of Crassostrea gigas were experimentally investigated with reference to effects of water temperature and size. Absorptiometric determinations of filtering rates with oysters being fed diatom Chaetoceros calcirtans were carried out in a closed system. Optical density of 675nm in path length 100mm cell used as the indication of food particles absorption was appeared directly In proportion with the concentration of diatom pigment $chlorophyll-\alpha$. In the closed system where $C_0$ is $OD_{675}$ at initial time 0, $C_t$, at time t, and Z is the decreasing coefficient of OD as meaning of instantaneous removal speed, then $C_t=C_0{\cdot} e^{-2t}$, $Z=In(C_t/C_0)/t$. On the assumption that the filtering rate is constant, then removal rate per unit time (d) is $d=-e^{-z}$. If t is used to time unit of hour (hr), the filtering rate (FR) in I/hr is given by $FR=V{\cdot}d=V(1-e^{-z})$, where V is the water volume (I) of the experimental vessel. Filtering rate increased as exponential function with increasing temperature while not over critical limit. The critical temperature for filtering rate was assumed to be between $28^{\circ}C$ and $29^{\circ}C$. And the weight exponent for filtering rate is 0.223. The model formula derived from the results as FR, $Ihr^{-1}$ = $Exp(0.208{\cdot}T-4.324){\cdot} (DW)^{0.223}$ (T<29 $^{\circ}C)$ where T is water temperature $(^{\circ}C

• Journal of Korea Port Economic Association
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• v.29 no.1
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• pp.99-122
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• 2013

International Exposition Yeosu Korea 2012 was held from May 12th 2012 to August 12th 2012 in New Port area of Yeosu-city, Jeollanam-do, Korea. 105 Nations and 10 international organizations participated in this mega event, and the total number of visitors amounts to 8.2 million. This study appraises the effectiveness of preparation for Yeosu Exposition. The main focus of this study is not on criticizing the problems that occurred in the transport measures. Instead, it looks at the current aspects of establishment and execution process and suggests how they can be applied differently in future transport management for international mega events held in Korea. The suggestions of this study are as follows. First, when establishing transport management plans for international mega events, the geographical features and trip resistance of the venue must be taken into consideration. Second, tasks should be distributed distinctly between the central government and the local government in order to prevent any dissension or inefficiency. Third, transport management needs to be consistent and transport guidance should be efficient in an effort to minimize visitor inconvenience. Last, transport management must be regarded as objective and rational from the outside view and the budget should follow timely based on this account.

• Journal of Korea Water Resources Association
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• v.51 no.6
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• pp.515-521
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• 2018

Seawater intrusion areas were calculated in Yeosu region considering sea level rise and the effects of countermeasures for seawater intrusion were analyzed using SEAWAT program. The estimated seawater intrusion area was $14.90km^2$ in 2015. When we applied climate change scenarios the area was changed to $19.19km^2$ for RCP 4.5 and $20.43km^2$ for RCP 8.5 respectively. The mitigation effects by artificial recharge with total $50m^3/d$, $100m^3/d$, and $300m^3/d$ are from 3.75% to 10.68% for RCP 4.5, and from 5.82% to 10.77% for RCP 8.5 respectively. If we install barrier wall with the thickness 0.8 m, 1.3 m, and 1.8 m, the mitigation effects are from 6.67% to 12.04% for RCP 4.5, and from 6.17% to 14.98% for RCP 8.5 respectively. The results of this study can be used to be a logical means of quantitative grounds for policy decisions to prevent groundwater contamination by seawater intrusion and subsequent secondary damage in coastal areas.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.1
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• pp.17-25
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• 1996

The results identified for bacterial flora 174, Vibrio spp.132, and coliform group 183 strains isolated from the areas of last China Sea and Yosu coastal sea during from August 6th. to 14th. 1992 were as follow: 40 strains among the 74 strains of bacteria flora isolated from fast China sea area were Pseudomonas spp.$(54\%)$ and 60 strains among the 100 strains isolated from Yosu sea area were Enterobacteriaceae $(60\%)$. Four strains were Vibrio alginoliticus and one strain of V, parahaemolyticus among 5 strains of genus Vibrio isolated from last China Sea. While 54 strains were V. alginolyticus $(43\%)$ and V, parahaemolyticus $(17\%)$ among 127 strains genus Vibrio isolated from Yosu coastal sea area. Seventy nine strains among the 156 strains of coliform group isolated from Vosu sea area were Escherichia coli I $(51\%)$ and each one strain Citrobacter freundii I and II. 3 strains among 27 strains isolated from last China sea area were E. coli$(11\%)$ and 1 strain of C. freundii I. Coliform group was grouped into 16 types by IMViC system, $44^{\circ}C$, gelatin liquefaction test.