• 한국환경생물학회:학술대회논문집
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• 한국환경생물학회 2002년도 춘계공동학술대회 및 심포지움 초록집
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• pp.45-45
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• 2002

• 대한환경공학회지
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• 제27권7호
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• pp.777-784
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• 2005

도시지역은 불투수층 면적비율이 높아 작은 강우에도 초기유출(first flush)이 강하게 발생하고 유출되는 오염물질 농도도 높다. 도로유출수에는 미세입자물질, 중금속, 유기물질 성분을 다량 함유하고 있다. 도로유출수의 수질과 입자의 유출특성을 파악하고자 교통량이 비교적 많은 도로 2개 지점을 대상으로 총 6회의 강우시료를 채수하여 분석하였다. 2개 조사 지점에서 분석된 도로유출수 수질농도범위는 SS $45{\sim}2,396\;mg/L$, $COD_{Cr}\;40{\sim}931\;mg/L$, TKN $0.1{\sim}19.6\;mg/L$, TP $0.2{\sim}25.1\;mg/L$, Fe $0.33{\sim}8.15\;mg/L$, Cr $0.06{\sim}0.50\;mg/L$, Pb $0.06{\sim}0.97\;mg/L$, Cr $0.01{\sim}0.12\;mg/L$으로 조사되었다. 강우초기의 농도는 극단적으로 높은 특성을 나타내었다. 도로유출수 SS와 상관계수가 높은 수질항목으로는 $COD_{Cr}$, TP, Cu, Pb이고, 상관계수가 가장 낮은 항목으로는 TKN으로 분석되었다. 도로유출수의 입경을 분석한 결과 평균 f3경간의 범위는 $6.7{\sim}23.4\;{\mu}m$이고 90% 입경의 범위는 $36.2{\sim}105.2\;{\mu}m$로 분석되었다. 또한, 입경은 유출량에 비례적으로 증가하는 경향을 나타내었다. 균등계수를 분석한 결과 평균범위는 $6.4{\sim}10.2$로 입경 분포범위가 크게 나타났다.

• 한국환경과학회지
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• 제15권9호
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• pp.819-827
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• 2006

We study on the dynamic interaction with a simulated physical-biological coupled model response to nutrient reduction scenario in Jinhae Bay. According to the low relative errors, high regression coefficients of COD and DIN, and realistic distribution in comparison to the observation, our coupled model could be applicable for assessing the marine ecosystem response to nutrient input reduction in Jinhae Bay. Due to the new construction and expansion of sewage treatment plant from our government, we reduce 50% nutrient inputs near Masan Bay and sewage treatment plant. COD achieves Level II in Korea standard of the water quality from the middle of the Masan Bay to all around Jinhae Bay except the inner Masan Bay remaining at Level III. When our experiment reduces 50% nutrient inputs near Masan Bay and Dukdong sewage treatment plant simultaneously, COD decreases to about 0.1-1.2 mg/L $(128^{\circ}30'{\sim}128^{\circ}40'\;E,\;35^{\circ}05'{\sim}35^{\circ}11'\;N)$. The COD from the middle of the Masan Bay to Jinhae Bay achieves Level II.

• Structural Engineering and Mechanics
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• 제27권4호
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• pp.425-438
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• 2007

Large changes in stiffness associated with cracking and yielding of reinforced concrete sections may be expected to occur during the dynamic response of reinforced concrete frames to earthquake ground shaking. These changes in stiffness in stories that experience cracking might be expected to cause relatively large peak interstory drift ratios. If so, accounting for such changes would add complexity to seismic design procedures. This study evaluates changes in an index parameter to establish whether this effect is significant. The index, known as the coefficient of distortion (COD), is defined as the ratio of peak interstory drift ratio and peak roof drift ratio. The sensitivity of the COD is evaluated statistically for five- and nine-story reinforced concrete frames having either uniform story heights or a tall first story. A suite of ten ground motion records was used; this suite was scaled to five intensity levels to cause varied degrees of damage to the concrete frame elements. Ground motion intensity was found to cause relatively small changes in mean CODs; the changes were most pronounced for changes in suite scale factor from 0.5 to 1 and from 1 to 4. While these changes were statistically significant in several cases, the magnitude of the change was sufficiently small that values of COD may be suggested for use in preliminary design that are independent of shaking intensity. Consequently, design limits on interstory drift ratio may be implemented by limiting the peak roof drift in preliminary design.

• Current Research on Agriculture and Life Sciences
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• 제32권4호
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• pp.203-209
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• 2014

This study investigated characteristics of rainfall and water quality in Saemangeum area with attention to temporal and spatial distributions. A high variability in rainfall was noted during July and August. The temporal analysis of water quality data indicated that DO and TN as well as BOD, COD and SS were within national standards except for increased concentrations during spring and summer, unlike TP values that indicated poor water quality. Standard deviation showed a high variability in SS among the seasons most especially during summer. The high dispersion indicated variability in the chemical composition of pollutants where the temporal and spatial variations caused by polluting sources and/or seasonal changes were most evident for BOD and COD during winter and spring. The box plots and bar charts showed steadily low concentrations of BOD, COD, TN and TP except within Iksan and notable significant variations in SS concentrations among the monitoring stations. Thus, high pollution levels requiring intervention were identified in Mangyeong river basin with particular concern for areas represented by Iksan station. It was noted that Iksan received a considerable amount of rainfall which meant high runoff which could explain the significant pollution levels revealed in the water quality spatial distribution. Major pollution contributing pollutants within Saemangeum area were identified as SS, BOD, COD and TN. Therefore the present results could be used as a guideline for the temporal and spatial distributions analysis of both rainfall and water quality in Saemangeum watershed.

• 해양환경안전학회지
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• 제5권2호
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• pp.57-65
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• 1999

The in situ observations and the seawater analyses were conducted at all seasons from July 1996 to April 1999 for the purpose of describing the characteristics of seasonal variations of water quality in Mokpo harbour, Korea. Vertical stratification started to be formed in water column in spring, developed in summer and disappeared in fall. In summer, vertical density distribution of water column was found to be in stable structure with lower temperature and higher salinity of bottom water, and the vertical mixing of water between surface and bottom layers was restricted. In winter, however, surface water was found to be similar to bottom water in temperature and salinity, and water column was in unstable structure and in well-mixed condition between surface and bottom waters. The saturation percentage of dissolved oxygen(DO) in bottom water of inner part of Mokpo harbour at all seasons was shown to be decreased to the third grade or under the third grade of Korean standards of seawater quality. In particular, dissolved oxygen was oversaturated in surface water and undersaturated in bottom water in summer, due to stratification and organic pollution. The difference of DO concentration between surface and bottom waters was found to be greater in spring and summer than in fall and winter, due to stratification and photosynthesis of phytoplankton. The concentrations of chemical oxygen demand(COD) over the entire waters of Mokpo harbour were found to fluctuate from below the third grade to the first grade of Korean standards through all seasons and COD concentrations of same seasons were shown to be different year after year. In particular, in view of COD, the annual average seawater quality of Mokpo harbour was evaluated to be in third grade of Korean standards, due to organic pollution. The average COD of surface water was greater than that of bottom water in spring and summer, due to the autochthonous COD caused by production of phytoplankton in surface waters, while the average COD of surface water was similar to that of bottom water in fall and winter, due to the vertical mixing of water between surface and bottom layers.

• 한국물환경학회지
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• 제23권1호
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• pp.72-80
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• 2007

The seasonal variation of organic matter and the oxidation efficiency of BOD and COD were investigated in several reservoirs and rivers located in the Han River system from March 2005 to April 2006. The concentrations of TOC in the Dong River, the Myeongjicheon stream and the Han-River varied with season. Mean concentration of TOC in the lotic environment ranged from 1.9 to 6.8 mgC/L. Oxidation efficiencies calculated from carbon were approximately 12.6 to 27.1% for BOD and 27.2 to 75.0% for COD, respectively. DOC to TOC ratio in the rivers ranged from 64.3 to 79.0%. Epilimnetic TOC concentrations in two clear and deep lakes (Lake Soyang and Paro) ranged from 2.0 to 2.8 mgC/L. TOC concentrations in the lower three dams (Lake Chunchon, Uiam, and Chungpyung) were relatively high that ranged from 3.4 to 3.7 mgC/L.Oxidation efficiencies in five lakes ranged from 10.6 to 17.2% for BOD and 32.6 to 49.5% for COD, respectively. The range of DOC to TOC in Lake Soyang and Paro was approximately 69. 0 to 73.4%. The ratios of lower three dams ranged from 48.2 to 62.3%. The differences among the lakes seemed to be asociated with limnological and hydrological characteristics of the lakes.

• 한국물환경학회지
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• 제33권3호
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• pp.341-347
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• 2017

From 2014 to 2016 water quality survey results according to the location and depth of Youngrang Lake are as follows: Distribution of dissolved oxygen in the water depth was investigated by the middle section and the downstream 1st, 3rd, 5th, when investigating bottem 1m interval anoxic layer. In organic matter and nutrient concentration distribution COD upstream 2.8 mg/L, middle section 4.2 mg/L downstream 4.1 mg/L, more than two times higher in bottem layer and TP concentrations showed a similar trend with COD, upstream of 0.047 mg/L, middle section was 0.051 mg/L, downstream of 0.059 mg/L. There was a difference in salinity every survey period the average salinity is lowest with 28.5‰ when the second survey. And the highest with 32.1‰ in the fourth investigation. Korean trophic state index($TSI_{KO}$) were showed eutrophic conditions in the middle section and downstream else showed mesotrophic state in the entire period. In order to evaluate the cause of water pollution Youngrang lake, regression analysis of the relationship between salinity and DO, COD, TN, TP, Chl-a results, $R^2$ is from 0.63 to 0.95 Youngrang lake water quality was found to have a close relationship with salinity due to inflow of seawater. As a result, in order to improve the quality of Youngrang lake efficient incorporation of the amount of water through the seawater influent as it is considered the key.

• 한국해안·해양공학회논문집
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• 제22권5호
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• pp.344-351
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• 2010

경기만과 한강하구의 장기적인 물질이동에 영향을 미치는 순 유량과 MIKE21 확산모형을 이용한 염분 및 COD 농도분포 예측결과에 대한 불확실성 분석을 수행하였다. 한강 하구 연안의 순 유량은 강화도 북단을 지나 교동도와 석모도를 통과하는 수량이 97% 정도로 대부분을 차지하고 있으며, 염하수로를 통과하는 수량은 3% 미만으로 파악되었다. 한편 확산모형을 이용한 염분 및 COD 농도 분포는 일 자료를 이용한 예측 결과를 기준으로 월별 자료를 이용한 예측결과와의 차이, 즉 중요한 입력 자료의 시간간격만의 차이에 의한 계산 결과의 차이로 정의되는 불확실성으로 정의하여 비교하였다. 그 결과 염하수로에서는 수량이 크게 증가하는 하계에 염분농도 차이가 -10~20 psu 정도, COD 농도차이는 ${\pm}1.0\;mg/L$ 정도로 파악되었으며, 한강하구에서 외해로 갈수록 그 영향은 크게 감소하고 있는 것으로 파악되었다.

• 해양환경안전학회지
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• 제17권2호
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• pp.105-121
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• 2011

본 연구에서는 시화호의 수질 관리 정책 연구를 위한 최근의 수질 자료 확보를 목적으로 2010년에 시화호 내 외측 해역에서 수질 조사를 수행하였다. 시화호 표층수 수질항목들의 수평적 농도분포는 하천을 통한 담수 유업과 배수갑문을 통한 외해수 유입의 영향으로 인하여 반윌 및 시화 산단 얀근 상류지역에서는 높고 배수갑문으로 갈수록 낮아지는 경향을 나타냈다. 시화호 외해에서는 TN 및 TP가 소래포구에 가까운 곳에서 높은 농도를 나타내었으며, 전체적으로 시화호 내해보다는 상대적으로 낮은 농도를 나타내었다. 시화호 내측의 경우, 여름철 성층 형성 및 저층의 활발한 유기물 분해로 빈산소층이 발달되고 있었다. 수질항목들의 수직적 농도분포의 경우, 용존영양염, TN 및 TP는 표층보다 저층에서 높았지만, COD, 클로로필-a 및 POC는 이와 반대로 저층보다 표층에서 높은 분포를 나타냈다. 시화호 표층수에서 염분은 용존영양염과 양호한 음의 상관성을 보여 담수 기원의 영양염 공급이 확인되었고, 이에 의한 식물플랑크톤의 대증식으로 COD 및 POC가 높게 나타났다.