• 한국농공학회지
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• 제32권E호
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• pp.33-46
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• 1990

Abstract Over 700/0 of the rural land area in Korea is mountainous and small watersheds provide most of the water resources for agricutural use. To provide an appropriate tool for the agricultural water resource development project, SNUA2, a mathematical model for simulating the physical processes governing the precipitation-runoff relationships and predicting the storm and long-term runoff quantities from the small mountainous watersheds was developed. The hydrological characteristics of small mountainous watersheds were reviewed to select appropriate theories for the simulation of the runoff processes, and a deterministic and distributed model was developed. In this, subsurface flows are routed by solving Richard's two dimensional equation, the dynamics of soil moisture contents are simulated by the consideration of phenological factors of canopy plants and surface flows are routed by solving the kinematic wave theory by numerical analysis. As a result of an application test of the model to the Sanglim watershed, peak flow rates of storm runoff were over-estimated by up to 184.2%. The occurence time of peak flow and total runoff volume of storm runoffs simulated were consistent with observed values and the annual runoff volumes were simulated in the error range of less than 5.8%.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.13-18
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• 2003

Heat pipes with binary mixture fabricated and tested for applications where condenser temperature is in a range of $10^{\circ}C$ to $130^{\circ}C$. The pipe materials 8.0 mm O.D. cupper tube and the working fluids are ethanol-water mixtures. The total length of test of the heat pipe was 1710mm in which evaporator section was 1570mm, adiabatic section was 50mm and condenser section was 90mm. Mixing ratios of ethanol and water could be variable in mole fraction. Temperature of condenser section was $10^{\circ}C$, $80^{\circ}C$ and $130^{\circ}C$. Heat pipe performance experimental study was accomplished with change of mixing ratio in these temperatures. The fill charge ratio was 20% of the heat pipe volume. Wick structure was woven-wire and method of experimental work was that thermal load was increased 20W step until the heat pipe wall temperature reached at $150^{\circ}C$. Results were following: At coolant $10^{\circ}C$ and $130^{\circ}C$, mixing ratio that have beat thermal performance was 0.8M+ and at coolant $80^{\circ}C$, was 0.3 ${\sim}$ 0.5 M+.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 1996년도 경북지부 결성 및 추계학술발표회 논문집
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• pp.131-139
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• 1996

To quantitatively investigate the effects of manure compost on the soil and water environment including ground water the elution patterns of anions and hydraulic conductivity wore estimated with four different depth(15, 30, 45 60cm) and four variable ratio of compost treatment(0, 2, 4, 6%) through soil column test. 1. There were over 95% of elution of chloride and nitrate within 0.1 pore volume(PV), and sulfate within 0.2 PV. With 2 ton/10a of cow manure compost treatment recommended total 40 kg/10a of anions added was recovered as effluent at the amount of 17kg chloride, 5.4kg nitrate, and 13.2kg sulfate, respectively However, phosphate rarely recovered in the effluent due to the strong affinity for sorption sites in soils. 2. In multi-layered soil column the maximum peaks of each anion eluted were retardated with increasing soil depth and the amount of organic matter(OM) treatment. 3. With increasing OM up to 2% the saturated hydraulic conductivity(SHC) was greatly decreased, but the slight decrease in SHC was found by addition of OM greater than 4％. In multi-layered soil column SHC was more effected by the lower SHV layer than by that of the higher.

• 농업과학연구
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• 제39권2호
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• pp.195-202
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• 2012

This study was examined the optimization of processing conditions for taste-assurance factors of boiled Korean native chicken (KNC) through response surface methodology. The effects of two independent variables, including heating time ($X_1$) and water volume ($X_2$), were investigated using central composite design. Hypoxanthine content, lipid oxidation, texture, and sensory results were chosen as dependent variable. Results showed high reliability on hypoxanthine and texture property in leg meat (not breast meat) of boiled KNC. Statistical modeling revealed that 3.5 folds of added water (v/w) based on chicken weight and 73.5 min of cooking time was the optimum for producing characteristic taste and textural properties from the leg meat of KNC.

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.654-664
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• 2018

Self-pressurization analysis of the natural circulation integral nuclear reactor through a new dynamic model is studied. Unlike conventional pressurized water reactors, this reactor type controls the system pressure using saturated coolant water in the steam dome at the top of the pressure vessel. Self-pressurization model is developed based on conservation of mass, volume, and energy by predicting the condensation that occurs in the steam dome and the flashing inside the chimney using the partial differential equation. A simple but functional model is adopted for the steam generator. The obtained results indicate that the variable measurement is consistent with design data and that this new model is able to predict the dynamics of the reactor in different situations. It is revealed that flashing and condensation power are in direct relation with the stability of the system pressure, without which pressure convergence cannot be established.

• 한국관개배수논문집
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• 제18권1호
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• pp.4-17
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• 2011

The standard design methodology was suggested to construct wetland system for reducing non-point source pollution from Saemangeum reclaimed paddy land. To set for the design flow and concentrations, runoff and water quality survey were conducted during the irrigation period in 2008 at Gyehwa reclaimed paddy land located at near Saemangeum lake. It is rational that 1ha is the optimum constructed wetland size. To meet this size, the moderate drainage area of reclaimed paddy field was 50ha under the conditions that rainfall is 30mm, average runoff coefficient is 0.83, and runoff capture ratio is 0.6. At these condition, the runoff volume from 50ha was 10,520 $m^3/d$ including base flow during irrigation period. To select the optimum wetland system, several case studies were conducted by focusing on the tidal reclaimed land areas having wetland systems in Seokmun. Pond-Wetland system was selected as the standard model because of showing the highest reduction efficiency. Single variable regression equation were delivered to estimate effluent water concentrations from the designed wetland by using long-term monitoring data from the Seokmun experiment site. The effluent concentration from the designed wetland using these equation were showed moderately range.

• 청정기술
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• 제19권1호
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• pp.8-12
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• 2013

가변부피 투시셀이 장착된 고압 상평형 장치를 사용하여 이산화탄소 + 계면활성제 이성분계와 이산화탄소 + 계면활성제 + 물 삼성분계의 상평형 거동을 318 K부터 348 K의 온도범위에서 관찰하였다. 계면활성제로는 소르비탄 모노팔미테이트를 사용하였다. 이산화탄소 + 소르비탄 모노팔미테이트 이성분계에서 관측된 운점압력은 온도가 상승함에 따라 증가하며, 소르비탄 모노팔미테이트의 조성이 0.226 wt%에서 최대 운점압력이 측정되었다. 반면에 계면활성제의 농도를 0.1 wt%로 고정한 삼성분계에서 관측된 운점압력은 온도와 물의 조성이 증가함에 따라 커지는 것을 확인할 수 있었다. 물의 농도를 0.2 wt%로 고정한 삼성분계에서의 압력-조성의 곡선은 상대적으로 수평의 형태를 나타냈다. 이 때, 운점압력은 온도와 계면활성제의 조성이 증가함에 따라 상승함을 확인할 수 있다.

• 자원환경지질
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• 제36권3호
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• pp.149-157
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• 2003

울릉분지 남서부 심해저 퇴적층에 분포하는 천부 가스의 특성을 파악하기 위해서 피스톤 코아시료를 채취하고 공기층 가스 기법으로 퇴적물 내에 함유된 가스를 포집하여 탄화수소 가스의 함량, 성분 및 탄소 동위원소 분석을 실시하였다. 또한 가스의 함량과 시추 코아 퇴적물의 연관성 및 특성을 파악하기 위해서 가스를 함유하는 퇴적물에 대해서 유기 지화학 분석을 실시하였다. 그리고 가스를 함유하는 퇴적물의 탄성파 특성을 살펴보았다. 퇴적물에서는 탄화수소 가스가 0.01%에서 11.25%까지 검출되었다. 단위 퇴적물내의 탄화수소 가스의 양을 젖은 퇴적물의 부피를 기준으로 정량적으로 계산하면 0.1에서 87.4ml/L wet sediment를 나타냈다. 분석된 탄화수소 가스의 성분은 주로 메탄으로 분석 시료에서 2개 시료를 제외하고는 메탄의 함유비가 98%이상을 나타냈으며 32개 분석 시료 중에서 15개 구간에서는 메탄만이 검출되었다. 채취된 시료의 메탄 가스의 탄소 동위원소 비$(\delta^{13}c)$는 -94.31$extperthousand$에서 -55.50$\textperthousand$까지의 범위를 나타내서 분석된 가스의 기원은 메탄 생성 박테리아에 의한 생물 기원 가스인 것으로 판명된다. 연구 지역의 퇴적물내의 탄화수소 가스의 함량은 지역에 따라서 차이를 보인다. 퇴적물내의 가스의 함량은 퇴적물의 지화학적 특성과 퇴적물의 입도와는 뚜렷한 상관 관계를 보이지 않았다. 단지 탄성파 단면상에서 이상대를 나타내는 곳에서는 가스의 함량이 많은 것으로 나타났다. 탄성파 단면상에 보이는 이상대는 현장의 온도 압력 조건에서 공극수에 탄화수소 가스가 과포화 된 곳으로 다른 조건이 만족된다면 가스 하이드레이트를 형성하기에 적합한 것으로 해석한다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.166-172
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• 2004

An underwater motion measurement system was constructed for applications to the model basin. A commercial motion capture system, FALCON of Motion Analysis Corp., which corrects automatically the distortion caused by refraction of the light passing through water and air, was adopted for underwater motion measurement. The modifications of FALCON system were performed: waterproofing camera housings, markers, connectors, and a new blue ring lighter. the accuracy of the motion measurement was obtained within the calibration error of 0.87mm in average and 0.89mm in standard deviation for the distance of 500mm between two markers on the calibration device. the volume of $2100mm(length)\times2100mm(breadth)\times2300mm(Height)$ was covered with 4 cameras of the underwater motion measurement system. For the performance verification, motion measurement test of a vertical mooring chain model excited at the top end was carried out. The 3D motions of mooring model were measured with variable amplitude and period of the forced excitation. Higher order motions of the mooring model were observed as the excitation period decreases. the performance of the system was verified by successfully measuring 3D motion of mooring model.

• 전력전자학회논문지
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• 제6권5호
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• pp.377-385
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• 2001

물을 전기분해하여 얻은 일정 부피비를 갖는 수소와 산소 혼합가스를 수산화가스로 명명하며, 이를 역반응시켜서 열 에너지원으로 사용하고 있다. 수산화가스는 경제성, 안전성 및 환경친화적인 고유한 특성을 지니고 있어서 현재 가스용접기에 적용하고 있으며 여러 가지 응용분야에 적용할 수 있도록 연구 중에 있다. 본 논문에서는 수산화가스의 특성에 관하여 고찰하고 발생기용 전원에 대하여 소개하고 이 중에서 아직까지 적용되지 않은 펄스전원을 적용하여 여러 가지 운전주파수에서 비교분석 하였다.