• 한국농공학회지
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• 제7권1호
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• pp.861-876
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• 1965

During my stay in the Netherlands, I have studied the following, primarily in relation to the Mokpo Yong-san project which had been studied by the NEDECO for a feasibility report. 1. Unit hydrograph at Naju There are many ways to make unit hydrograph, but I want explain here to make unit hydrograph from the- actual run of curve at Naju. A discharge curve made from one rain storm depends on rainfall intensity per houre After finriing hydrograph every two hours, we will get two-hour unit hydrograph to devide each ordinate of the two-hour hydrograph by the rainfall intensity. I have used one storm from June 24 to June 26, 1963, recording a rainfall intensity of average 9. 4 mm per hour for 12 hours. If several rain gage stations had already been established in the catchment area. above Naju prior to this storm, I could have gathered accurate data on rainfall intensity throughout the catchment area. As it was, I used I the automatic rain gage record of the Mokpo I moteorological station to determine the rainfall lntensity. In order. to develop the unit ~Ydrograph at Naju, I subtracted the basic flow from the total runoff flow. I also tried to keed the difference between the calculated discharge amount and the measured discharge less than 1O~ The discharge period. of an unit graph depends on the length of the catchment area. 2. Determination of sluice dimension Acoording to principles of design presently used in our country, a one-day storm with a frequency of 20 years must be discharged in 8 hours. These design criteria are not adequate, and several dams have washed out in the past years. The design of the spillway and sluice dimensions must be based on the maximun peak discharge flowing into the reservoir to avoid crop and structure damages. The total flow into the reservoir is the summation of flow described by the Mokpo hydrograph, the basic flow from all the catchment areas and the rainfall on the reservoir area. To calculate the amount of water discharged through the sluiceCper half hour), the average head during that interval must be known. This can be calculated from the known water level outside the sluiceCdetermined by the tide) and from an estimated water level inside the reservoir at the end of each time interval. The total amount of water discharged through the sluice can be calculated from this average head, the time interval and the cross-sectional area of' the sluice. From the inflow into the .reservoir and the outflow through the sluice gates I calculated the change in the volume of water stored in the reservoir at half-hour intervals. From the stored volume of water and the known storage capacity of the reservoir, I was able to calculate the water level in the reservoir. The Calculated water level in the reservoir must be the same as the estimated water level. Mean stand tide will be adequate to use for determining the sluice dimension because spring tide is worse case and neap tide is best condition for the I result of the calculatio 3. Tidal computation for determination of the closure curve. During the construction of a dam, whether by building up of a succession of horizontael layers or by building in from both sides, the velocity of the water flowinii through the closing gapwill increase, because of the gradual decrease in the cross sectional area of the gap. 1 calculated the . velocities in the closing gap during flood and ebb for the first mentioned method of construction until the cross-sectional area has been reduced to about 25% of the original area, the change in tidal movement within the reservoir being negligible. Up to that point, the increase of the velocity is more or less hyperbolic. During the closing of the last 25 % of the gap, less water can flow out of the reservoir. This causes a rise of the mean water level of the reservoir. The difference in hydraulic head is then no longer negligible and must be taken into account. When, during the course of construction. the submerged weir become a free weir the critical flow occurs. The critical flow is that point, during either ebb or flood, at which the velocity reaches a maximum. When the dam is raised further. the velocity decreases because of the decrease\ulcorner in the height of the water above the weir. The calculation of the currents and velocities for a stage in the closure of the final gap is done in the following manner; Using an average tide with a neglible daily quantity, I estimated the water level on the pustream side of. the dam (inner water level). I determined the current through the gap for each hour by multiplying the storage area by the increment of the rise in water level. The velocity at a given moment can be determined from the calcalated current in m3/sec, and the cross-sectional area at that moment. At the same time from the difference between inner water level and tidal level (outer water level) the velocity can be calculated with the formula $h= \frac{V^2}{2g}$ and must be equal to the velocity detertnined from the current. If there is a difference in velocity, a new estimate of the inner water level must be made and entire procedure should be repeated. When the higher water level is equal to or more than 2/3 times the difference between the lower water level and the crest of the dam, we speak of a "free weir." The flow over the weir is then dependent upon the higher water level and not on the difference between high and low water levels. When the weir is "submerged", that is, the higher water level is less than 2/3 times the difference between the lower water and the crest of the dam, the difference between the high and low levels being decisive. The free weir normally occurs first during ebb, and is due to. the fact that mean level in the estuary is higher than the mean level of . the tide in building dams with barges the maximum velocity in the closing gap may not be more than 3m/sec. As the maximum velocities are higher than this limit we must use other construction methods in closing the gap. This can be done by dump-cars from each side or by using a cable way.e or by using a cable way.

• Ecology and Resilient Infrastructure
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• 제2권3호
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• pp.216-223
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• 2015

본 연구는 영주댐 건설사업 영향에 따른 멸종위기야생생물 1급 어류 흰수마자의 보전을 위하여 수몰예정지 내 흰수마자를 서식적합지로 이주시키고, 댐에 의한 내성천 상하류 단절 및 유전적 폐쇄에 대비하여 인공종묘생산 및 복원을 통해 내성천에 치어를 방류하여 그 결과를 관찰하였다. 영주댐 수몰예정지 내 흰수마자는 8회 이상 포획 시도에도 불구하고 서식이 확인되지 않아 이주가능지로 이주는 이루어지지 않았다. 내성천에서 포획한 친어 40개체를 통해 인공종묘생산한 치어 5,000개체는 친어의 유전 다양성을 물려받은 것으로 분석되었으며, 사전에 물리적, 생물학적 환경조건 분석을 통하여 자연 서식지와 유사한 최적방류지를 선정하여 인공종묘생산 치어를 방류하였다. 초기에는 방류지점을 중심으로 미소분산이 이루어졌으나, 시간흐름에 따라 확산이 진행되면서 재포획 개체수가 감소하였다. 포획된 방류 개체들은 내성천 자연생태환경에 적응하여 서식하고 있으며, 복부 팽만도가 높고 총배설공으로 배설물이 확인되는 점으로 보아 자연 먹이 섭식이 정상적으로 이루어지고 있는 것으로 나타났다. 따라서 인공종묘생산에 의한 영주댐 상하류 내성천 흰수마자 유전적 동질성 확보와 복원 개체군의 증강에 일차적 성공이 이루어지고 있는 것으로 파악되었으며 향후 장기적인 모니터링을 통한 지속적인 효과 분석이 필요할 것으로 전망되었다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권10호
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• pp.894-898
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• 2016

Solution plasma is a unique method which provides a direct discharge in solutions. It is one of the promising techniques for various applications including the synthesis of metallic/non-metallic nanomaterials, decomposition of organic compounds, and the removal of microorganism. In the context of nanomaterial syntheses, solution plasma has been utilized to produce carbon nanoparticles and metallic-carbon nanoparticle systems. The main purpose of this study was to synthesize nickel nanoparticles embedded in a matrix of carbon particles by solution plasma in one-step using waste vegetable oil as the carbon source. The experimental setup was done by simply connecting a bipolar pulsed power generator to nickel electrodes, which were submerged in the waste vegetable oil. Black powders of the nickel nanoparticles-embedded carbon (NiNPs/Carbon) particles were successfully obtained after discharging for 90 min. The morphology of the synthesized NiNPs/Carbon was investigated by a scanning electron microscope, which revealed a good dispersion of NiNPs in the carbon-particle matrix. The X-ray diffraction of NiNPs/Carbon clearly showed the co-existence of crystalline Ni nanostructures and amorphous carbon. The crystallite size of NiNPs (through the Ni (111) diffraction plane), as calculated by the Scherrer equation was found to be 64 nm. In addition, the catalytic activity of NiNPs/Carbon was evaluated by cyclic voltammetry in an acid solution. It was found that NiNPs/Carbon did not show a significant catalytic activity in the acid solution. Although this work might not be helpful in enhancing the activity of the fuel cell catalysts, it is expected to find application in other processes such as the CO conversion (by oxidation) and cyclization of organic compounds.

• 한국음향학회지
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• 제34권4호
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• pp.288-294
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• 2015

광섬유 사냑 간섭계는 음향 및 진동과 같은 물리적 변화량을 탐지하는 센서로 잘 개발되어 있다. 본 논문에서는 변압기유가 채워진 원통형 캐비티에 음압이 발생되었을 때 한 개의 루프내에 설치된 광섬유 배열 센서를 이용하여 음향을 탐지하였다. 서로 다른 외부 음향 주파수 $f_1$과 $f_2$를 피에조 재료를 이용하여 발생시키고 주파수는 5 kHz에서 90 kHz까지로 선정하였다. 실험 결과 광섬유 센서는 하모닉 성분인 $f_1$, $f_2$, $2f_1$, $2f_2$, ${\mid}f_1-f_2{\mid}$, ${\mid}f_1+f_2{\mid}$의 주파수를 탐지하였다. 제안된 광섬유 센서 배열은 변압기 내의 부분 방전으로 인한 음압과 진동과 같은 물리량을 모니터링 하는데 적용할 수 있을 것으로 판단된다.

• 대한토목학회논문집
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• 제38권2호
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• pp.261-268
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• 2018

본 연구에서는 홍수총량을 시간에 따라 분포시키는 단순홍수범람해석 모형인 SIMOD(Simplified Inundation MODel)를 이용하여 도심지 침수분석을 실시하고자 하였다. 기존의 침수분석 모형들은 입력자료 구축이 어렵고, 분석시간이 오래 걸리는 등의 단점을 가지고 있다. SIMOD는 다중흐름방향법(Multi Direction Method, MDM)과 평수가정법(Flat-Water Assumption, FWA)의 두 흐름 방정식으로 홍수흐름을 단순화시킨 모형으로, 대상지역의 지형자료와 유입 홍수량 등 간단한 수문자료만을 이용하여 홍수범람에 의한 침수경로 분석이 가능하여 신속한 모델링으로 빠른 의사결정을 할 수 있다는 장점이 있다. 따라서 SIMOD 모형을 이용하여 도심지 침수분석을 실행한 뒤, 기존의 침수분석 모형인 FLO-2D 모형분석결과와 비교를 시행하여 모형의 적용성을 분석하였다. 대상지역은 도심지 지역의 제방 월류-파제 시나리오를 적용하기 위해 하천이 인접해 있고, 충분한 높이의 제방이 있는 금호강 하류에 위치한 성서제를 대상지역으로 선정하였으며, 지형자료는 기존의 침수분석에 사용하는 DEM지형자료와 도심지 건물군, 도로 분포 등을 표출할 수 있는 DSM지형자료를 이용하였다. 입력 홍수량은 200년 빈도계획홍수위를 기준으로 제방파제시나리오를 적용 사각웨어식을 적용하여 산정하였으며, 1~24시간의 모의시간과 침수면적을 비교 분석하였다. SIMOD의 경우 24시간 모의시간이 7분 안으로 나타났으며 면적차이는 FLO-2D와 비교했을 때 20% 내외로 나타났다. 또한 DSM을 이용하여 분석한 결과 도로나 건물의 영향이 반영되어 앞으로 도심지에서 DSM을 이용한 지형자료의 필요성을 확인하였다.

• 한국물환경학회지
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• 제34권4호
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• pp.363-374
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• 2018

The Han River serves as an important water resource for the city of Seoul, Korea and in the neighboring metropolitan areas. From the Paldang dam to the Jamsil submerged weir, the 4 water intake stations that are located for the Seoul metropolitan population were under review in this study. Therefore the water quality management in this section is very important to monitor, analyze and review to rule out any safety concerns. In this study, a 3-D hydrodynamic model, EFDC (Environmental Fluid Dynamics Code), was applied to the downstream of the Paldang Dam in the Han River, which is about 23 km in length, to determine issues related to water resource management. The 3-D grid was composed of 2,168 horizontal grids and three vertical layers. In this case, the hydrodynamic model was calibrated and verified with an observed average daily water surface elevation, water temperature and flow rate data for 3 years (2013~2015). The developed EFDC model proved to reproduce the hydrodynamics of the Han River well. The composition ratios of the noted incoming flows at the monitored intake stations for 3 years and their flow patterns in the river were analyzed using the validated model. It was found that the flow of the Wangsuk Stream depended on the Paldnag dam discharge, and it was noted that the composition ratios of the stream at the intake stations changed accordingly. In a word, the Wangsuk Stream moved mainly along the right bank of the Han River under the condition of a normal dam flow. As can be seen, when the dam discharge rate was low, the incidence of lateral mixing was often seen. The scenario analyses were also conducted to predict the transport of conservative pollutants as in the case of a chemical spill accident. Generally speaking, when scenarios were applied, the arrival time and concentration of pollutants at each intake station was thus predicted.

• 대한토목학회논문집
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• 제31권6B호
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• pp.507-514
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• 2011

본 논문에서는 하천에 유입되는 열 오염물질의 혼합거동을 분석하기 위해 2차원 수심 평균된 이송-분산방정식에 유한요소법을 적용하여 수치 모형을 개발하였다. 유한요소법의 여러 수치기법 중 SUPG법을 적용하였으며, 복잡한 하천경계를 보다 정확히 재현할 수 있도록 삼각 및 사각 요소망의 혼용이 가능하도록 하였다. 열 오염물질의 거동을 표현하기 위해서 열 교환을 묘사하는 반응항을 평형온도와 수온과의 차이에 비례하는 식으로 나타내고, 열교환 계수 및 평형온도에 따라 수온의 변화가 적용되도록 방정식을 구성하였다. 모형의 검증을 위하여 직사각형 수로에 선원으로 연속주입하여 얻은 수치해와 1차원 정상상태의 해석해를 비교하였다. 비교결과 수치해와 해석해의 결과가 서로 일치하는 것으로 밝혀졌다. 모형의 현장적용을 위해 상수원 보호구역인 팔당댐 하류부터 잠실수중보까지 22.5 km 구간을 대상영역으로 하였다. 구리하수처리장 방류수에 의한 수온 변화를 모의한 결과 수질측정망 측정자료와 비교적 비슷한 경향이 나타났다. 본 연구에서 개발한 수치모형이 열 오염원 유입으로 인한 수온 변화를 잘 표현하는 것을 알 수 있었다.

• 한국수자원학회논문집
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• 제45권3호
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• pp.331-347
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• 2012

남강댐 하류는 부산 경남의 수자원 장기 계획에 중요한 지역이므로 지속가능한 지표수 관리 및 오염원 제어를 위해 흐름 및 수질 해석이 필요하다. 따라서 본 연구에서는 2차원 수질모형인 RAM4와 3차원 수질모형인 WASP을 각각 수리모형인 RAM2 및 EFDC모형과 연계하여 2 3차원 준연계 모형을 이용한 남강댐 하류에서의 수리 및 수질을 해석하였다. 2차원 흐름해석 모형인 RAM2 적용 결과 만곡부 5개 횡단 측선에서의 유속의 증감경향이 ADCP 실측값과 잘 일치하였으며, 3차원 모형인 EFDC와 유속 분포 및 보 월류 유속이 유사하였다. 또한 정상상태 도달 후의 RAM2-RAM4 연계모의에 의한 BOD 농도와 EFDC-WASP 연계모의에 의한 BOD 농도장이 모의영역 전반에 걸쳐 유사하게 나타났다. 남강댐 하류부의 경우 수리 및 수질이 남강댐 방류량에 크게 좌우되며 남강댐의 수량은 하류부의 수질 및 연안 어업환경에 큰 영향을 미치므로 향후 이에 대한 정량적 분석 시 계산의 효율성 및 모형의 적용성 측면에서 2차원 준연계 모형을 적용하는 것이 바람직한 것으로 판단된다.

• 환경영향평가
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• 제16권2호
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• pp.143-156
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• 2007

This study has researched the management status and the pollution level of water, soil, stream sediments of 11 abandoned coal mines out of a total of 12 within Obong-Dam area except Bukyung mine, which was submerged when constructing Obong-Dam, and selected areas which are in needs to have pollution control facilities in the first place. From the results of examination on the runoff at the waste rock pile and mineheads, the runoff from Sueun mine (pH, Fe, Al), Samwon mine (pH, Al), Wangdo mine (pH, Al), Mose mine (pH, Fe, Al) and Daeryeong mine (pH) exceeded the permissible discharge standards of the water quality, but the water at merging point with Obong-Dam after joined with Doma branch satisfied both Water Quality Standards and Drinking Water Quality Standards. In regard to groundwater contamination, it is found that areas where exceeded the Drinking Water Quality Standards are Wangdo mine (pH), Jangjae mine (pH, Zn), Daeryeong mine (pH) whereas all areas satisfied Soil Contamination Warning Standards of Soil Environmental Conservation Law. When comparing a research result on underwater sediments of branches of abandoned mines to the EPA Guidelines for classification of great lakes harbor sediments, Dongguk Gaerim (Fe), Jungwon mine (Fe), Daebo mine (Mn), Samwon mine (Mn) and Daeryeong mine (Mn) showed mid-level of contamination, whereas Sueun (Fe, Mn), Daebo mine (Fe), Woosung mine (Fe, Mn), Wangdo mine (Fe, Mn), Mose mine (Fe) and Daeryeong mine (Fe) showed high-level of contamination. In addition, contamination levels of underwater sediments in Wangsan and Doma branch where abandoned mine's branches merge together, Wangsan branch showed no contamination at all whereas Doma branch shows mid-level of contamination which reflect the Doma branch is affected by waste rock pile and minehead runoff of the abandoned mines in the Doma branch area. It is concluded that Mose mine and Sueun mine required treatment of acid mine drainage. and Wangdo, Jungwon, and Samwon mines were in need of mine tailing and erosion control work. The Samwon mine additionally required a control system for closed minehead runoff. Although the Samwon mine reached a high concentration of Al, Mn $Ca^{2+}$, $SO{_4}^{2-}$ in the runoff, the levels decreased after it was combined with a tributary. It has been concluded that after further monitoring of the cause of pollution, a preventive measure system may be needed to be built.

• 한국해양학회지:바다
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• 제18권2호
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• pp.65-69
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• 2013

대륙주변해인 동해의 일차생산력은 조사하기 쉬운 듯하지만 해황의 역동적 변동성 때문에 현장 관측으로 파악하기 매우 어렵다. 이 연구에서는 난수역의 평균적인(총)일차생산 배경값을 생지화학적 가설에 기반하여 추정하였다. 계산에 사용된 비혼합-부상 가설은 일단 일차생산이 오로지 대한해협을 통해 수송된 영양염에 의해서만 일어난다고 가정했을 경우로서, 결과($209\;gC\;m^{-2}\;y^{-1}$)는 발표된 위성기반 순일차생산력과 대등한 것으로 나타났다. 그런데 일차생산이 100% 신생산에 의존한다고 가정했었기 때문에 이 구속을 풀어 신생산지표를 0.6이라 가정하면 일차생산력은 40% 가량 높아진다. 결과는 오로지 대한해협을 통해 유입되는 영양염만으로도 기존에 알려진 일차생산을 지지하고도 남음을 말해준다. 그런데 배경값을 구하기 위해 배제시켰던 여러 가지 변동 요인들, 예컨대 용승, 지하수 유입, 대기 유입, 해양 투기, 태풍 등 배경에 더 해지는 교란은 모두 일차생산을 추가로 부양하는 요인이고, 여기에 아직 정량화 되지 못한 초미소남세균의 광합성에 대한 기여까지 고려하게 되면 실제 일차생산력은 배경값의 두 배 이상도 가능할 것으로 추정된다. 이 경우에 일차생산력은 신생산지표가 0.6으로 알려진 페루 용승역과 비등한 규모가 된다.