• 한국물환경학회지
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• 제32권6호
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• pp.628-648
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• 2016

Increased attention has been paid to the presence of veterinary antibiotics in various environmental matrices due to their toxicological behavior in the ecosystem and development of antibiotic-resistant strains of pathogenic bacteria. In the this review, 37 target antimicrobials were selected based on annual sales of antibiotics for livestock in South Korea 2014. Also, extraction and clean-up methods for the determination of the antibiotic residues in liquid samples including water, milk, and honey were comprehensively reviewed in the literature. Solid-phase extraction (SPE) was commonly used as a pre-treatment method for the samples. Most of the analytes were extracted in acidic conditions (2.5~4.0) except for aminoglycosides, which were extracted in neutral conditions (7.0~8.0). ${\beta}-Lactams$ showed the highest recoveries in neutral pH due to their degradation characteristics in acidic media. Starta-X, Oasis HLB, and Oasis MCX were frequently applied as an SPE cartridge and Oasis HLB showed the highest recoveries for the majority of antibiotic classes. The homogenized honey and milk were extracted by mixing with acids for deproteinization. Solids and other interfering substances in the extract were eliminated by centrifugation followed by membrane filtration or SPE before injection into HPLC.

• 한국물환경학회지
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• 제34권3호
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• pp.270-284
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• 2018

Paldang is a river reservoir located in the Midwest of Korea, with a water volume of $244{\cdot}10^6m^3$ and a water surface area of $36.5km^2$. It has eutrophied since the construction of a dam at the end of 1973, and the phosphorus concentration has decreased since 2001. Average hydraulic residence time of the Paldang reservoir is about 10 days during the spring season and 5.6 days as an annual level. The hydraulics and water quality of the reservoir can differ greatly, both temporally and spatially. For the spring period (March to May) in 2001 ~ 2017, the reservoir mean total phosphorus concentration calculated from the budget model based on a plug-flow system (PF) and a continuous stirred-tank reaction system (CSTR) was 13 % higher and 10 % lower than the observed concentration, respectively. A composite flow system (CF) was devised by assuming that the transition zone was plug flow, and that the lacustrine zone was completely mixed. The mean concentration calculated from the model based on CF was not skewed from the observed concentration, and showed just 6 % error. The retention coefficient of the phosphorus derived from the CF was 0.30, which was less than those of the natural lakes abroad or river reservoirs in Korea. The apparent settling velocity of total phosphorus was estimated to be $93m\;yr^{-1}$, which was 6 ~ 9 times higher than those of foreign natural lakes. Assuming CF, the critical load line for the total phosphorus concentration showed a hyperbolic relation to the hydraulic load in the Paldang reservoir. This is different from the previously known straight critical load line. The trophic state of the Paldang reservoir has recently been estimated to be mesotrophic based on the critical-load curve of the phosphorus budget model developed in this study. Although there is no theoretical error in the newly developed budget model, it is necessary to verify the validity of the portion below the inflection point of the critical-load curve afterwards.

• 한국태양에너지학회 논문집
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• 제31권6호
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• pp.95-102
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• 2011

The purpose of study is to estimate heating, cooling load performance and economic efficiency in office building with applied the functional paint. this paint can reduced SHGC(Solar Heat Gain Coefficient) on the glazing surface by coating. In this study, estimated to compared with double glazing, low-e glazing, IP(Insulation Paint) and IPu(Insulation UV-Cut Paint) coating glazing. As a result of this study, 1)heating & cooling load Analysis, SHGC value and U-factor of double glazing is about 0.70 and 3.29($W/m^2K$). low-E glazing is about 0.65 and 2.70($W/m^2K$). Two-side it is about 0.27 and 3.25($W/m^2K$). When compared to double glazing, annual heating & cooling load of low-E glazing, Two-side IPu and IP paint coating glazing is 3,012MWh($124kWh/m^2$), 2,910MWh($120kWh/m^2$), 2,867MWh($118.4kWh/m^2$) and 2,867MWh($118.4kWh/m^2$). It i sreduced to 2.0%, 5.2%, 6.7%, and 6.7% respectively. 2)the estimation of economic efficiency, low-e glazing installed in office building can not recover the investment within a lifetime 40years. but IPu and IP paint, two-side coating in glazing, have a payback period of 13 years respectively.

• 한국태양에너지학회 논문집
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• 제38권4호
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• pp.55-66
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• 2018

nZEH (net-Zero Energy House) is defined as a self-sufficient energy building where the sum of energy output generated from new & renewable energy system and annual energy consumption is zero. The electricity generated by new & renewable energy system with the form of distributed generation is preferentially supplied to electrical demand, and surplus electricity is transmitted back to grid. Due to the recent expansion of houses with photovoltaic system and the nZEH mandatory by 2025, the rapid increase of distributed generation is expected. Which means, we must prepare for an electricity-power accident and stable electricity supply. Also electricity charges have to be reduce and the grid-connected should be operated efficiently. The introduction of ESS is suggested as a solution, so the analysis of the load matching and grid interaction is required to optimize ESS design. This study analyzed the load matching and grid interaction by expected consumption behavior using actual data measured in one-minute intervals. The experiment was conducted in three nZEH with photovoltaic system, called all-electric houses. LCF (Load Cover Factor), SCF (Supply Cover Factor) and $f_{grid}$ (Grid Interaction Index) were evaluated as an analysis indicator. As a result, LCF, SCF and $f_{grid}$ of A house were 0.25, 0.23 and 0.27 respectively; That of B house were 0.23, 0.23, 0.19, and that of C were 0.20, 0.19, 0.27 respectively.

• 한국태양에너지학회 논문집
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• 제31권2호
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• pp.135-142
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• 2011

Architectural market in the world is trying to develop Zero Carbon Buildng that doesn"t use fossil fuel. Residential building that thermal load such as heating and domestic hot water is over 70% in energy consumption is easy to make Zero Carbon Building compared with office building that is mainly electric load. So, As a preliminary for analyzing the effect of Solar thermal system in the building, an annual energy consumption of residential building and total heat loads are calculated. Based on this result, three alternatives of solar thermal system for hot water and heating are applied in the building while installation area is increasing. Solar thermal system is applied on balcony and roof of apartment building as the way to reduce thermal load. In the first case that solar thermal system for hot water is applied on the balcony, optimum installation area is $56m^2$. And you could install $40m^2$ of this system in the roof that angle is $30^{\circ}$. In the second case of solar thermal system for heating and hot water, you can install $40m^2$ on the roof. As a result of economic evaluation, the most economical application method is to install $40m^2$ of solar thermal system for only hot water on the roof of the building. At that time, you can payback the initial investing cost within 10 years. And carbon emission of this method can be reduced until about 4 ton per year.

• 대한환경공학회지
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• 제36권6호
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• pp.451-459
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• 2014

본 연구에서는 2012년부터 수질오염총량관리 시행계획이 시행중인 진위천 수계의 연차별 지역개발 및 삭감계획을 평가하여 최종년도 할당부하량 및 목표수질을 만족하기 위한 방향성을 제시하고자 하였다. 진위천 수계 8개 자치단체의 시행계획을 분석한 결과, 대부분의 지자체에서 삭감계획보다 개발계획의 연차별 진행률이 빠른 경향을 보였다. 군포시, 용인시, 화성시는 2020년, 평택시는 2018년, 안성시는 2015년, 오산시는 2019년이 되어서야 삭감계획 진행율이 개발계획 진행율 보다 높거나 같아졌다. 주요 삭감방법은 하수처리시설 신증설, 방류수질 개선, 축산폐수 및 고형물의 자원화, 비점저감시설 확충 등 이었으며, 특히 축산산업이 활발한 지역의 특성이 반영되어 총 삭감률 중 가장 높은 비율을 차지하는 삭감방법은 축산폐수 및 고형물의 자원화로 삭감률은 34.1%에 해당되었다. 진위천 수계의 수질오염총량제가 성공적으로 정착하기 위해서는 삭감계획 및 지역개발계획의 체계적인 관리를 포함하여 기초자치단체의 적극적인 의지가 무엇보다 중요할 것으로 판단된다.

• 한국농공학회지
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• 제45권7호
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• pp.49-56
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• 2003

Nonpoint source pollutant loading from watershed may cause a problem to the water quality of the reservoir and stream. The characteristics of stream flow and water quality were monitored to investigate the runoff loading of the Namdae-cheon watershed from May in 1999 to October in 2003. Stage-discharge rating curve at the stream gauging site was established, and annual stream runoff of the study watershed was estimated as 499.4∼1,330.8mm during four years. The concentrations of total-nitrogen and total-phosphorus of stream water quality ranged from 0.76 to 6.95mg/L and from 0.0010 to 0.2276 mg/L, respectively, where T-N was generally higher than the water quality standard 1.0 mg/L for agricultural water use. The loads by unit generation of pollutant mass with respect to population, livestock, land use in this watershed were calculated. The runoff pollutant loadings by concentrations of total-N and total-P were estimated during study period, where the annual runoff loading of total-P was much less than the load by pollutant mass unit generation. The relations between stream discharge and water quality were analysed, and there was a high correlation for total-N but low for total-P. These results will be used to develop the monitoring techniques and water quality management system of agricultural watershed.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.190-195
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• 2008

The objective of this research is to determine overall heat transfer coefficients (K-value) of exterior wall, floor, and roof of Nakseonjae, a Korean traditional residence via field measurement of transient heat flow and temperature difference across each envelope component. Heat flow sensors and T-type thermocouple were attached on the internal and the external surface of each building component, and real-time measurement data were collected for the three consecutive summer days. The K-values determined in this research showed good agreement with other results from open literature. Peak and annual thermal loads of the traditional residence estimated by a commercial energy simulation program were compared with those for a current apartment house. The traditional house showed lower annual cooling load than that of the current building. It may caused by the fact that the traditional building has less air-tight envelopes and no fenestration passing direct solar radiation into the space.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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• pp.117-119
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• 1995

For an effective application of the cogeneration system for commercial and industrial buildings, we need to develop a relevant model to determine the long-term based optimal sizing of the cogeneration system considering electrical and thermal load demands, buy and sell contracts with electric utility and the annual production cost. In assessing the optimal sizing of cogeneration, we have to consider both economic parameters and their capacity expansion for the increased electrical and thermals demand in the future. In this paper, we propose a mathematical model for the optimal sizing of cogeneration systems considering annual production costs and other economic parameter such as, lifetime of the equipment, time value of the capital, etc. In the case study, we thoroughly examine the effects of the economic parameters and determine the optimal size of the sample system. In addition, we calculate the payback period of the cogeneration investment.

• 물과 미래
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• 제24권1호
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• pp.63-71
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• 1991

본 연구는 터널식 소수력 발전소의 타당성 검토 기법에 관한 것으로 개발 후보지의 유량지속곡선을 작성하기 위해서 Weibull분포의 누적밀도함수와 Thiessen법을 채택하였고, 터널식 소수력 발전소의 성능예측 모델과 건설비 산정 모델이 개발되었다. 또한 한강 수계에 산재한 8개소의 개발후보지를 선정, 실측하여 이들을 대상으로 성능 특성 및 경제적 타당성을 분석하였다. 분석 결과, 터널식 소수력 발전소의 경우 발전단가를 가장 낮게 하여 주는 최적 설계유량은 유량지속곡선상의 시간비가 20%에서 30%사이에 해당하는 유량이라는 것이 밝혀졌다. 또한 개발 후보지의 설계유량, 유효낙차, 설비용량, 년평균 가동율, 년간 전기 생산량 등과 같은 초기설계제원이 산정되었다.