• 한국수자원학회논문집
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• 제35권2호
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• pp.195-201
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• 2002

본 연구에서는 자연하천의 만곡수로에서 종방향 유속으로 인해 현재보다 더 이상 횡 방향 경사의 변형이 일어나지 않아 세굴이 감소하고 하상이 횡방향으로 안정한 상태를 유지할 수 있는 적정 유속의 한계인 한계속도를 제시하였다. 한계속도의 이론 유도는 하상횡경모형의이론적 배경이 되는 운동량모멘트방정식으로부터 얻은 하상면 횡방향전단력성분과 이에 대응하는 하상전단력과의 힘의 평형으로부터 유도되었다. 이론식의 검증을 위해 4개 자연하천수로의 실측자료론 적용하여 계산치와 실측치를 비교한 결과 잘 일치하였다. 적용결과에서 보정계수와 만곡수로의 평균입자 Froude수는 밀접한 상관관계를 갖고 있는 것으로 나타났다.

• Nuclear Engineering and Technology
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• 제16권3호
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• pp.161-168
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• 1984

습윤 조건하에서 triethylenediamine (TEDA) 합침황성탄소층의 시간에 따른 methyl iodide제거 효율을 예측하기 위한 흡착모델이 제안되었다. 습윤 조건하에서 평형 흡착용량과 유효 가공 확산 계수의 감소가 고려되었다. 예측된 값은 실험결과와 비교되었다.

• 물과 미래
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• 제26권4호
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• pp.107-115
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• 1993

본 연구는 3가지 교각형상에 대하여 국부적 정지상세굴에 대한 수리실험결과를 분석한 것이다. 실험결과에 의하면 국부적 상대세굴심은 교각형사, 하상입경의 기하표준편차, 유속비, 교각 푸르드수와 관계가 있는 것으로 나타났다. 교각의 상대세굴심은 반원사각형교각에서 가장 작고 하상재료가 균일할 때 보다 불균일할 때 현저하게 작게 나타났다. 입도의 불균일성으로 인한 세굴감소효과는 Raudkivi와 Ettema의 연구결과와 비교 검토하였다.

• 한국대기환경학회지
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• 제16권4호
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• pp.399-408
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• 2000

This study evaluated the SO2 adsorption characteristics using a continous moving bed system. Natural manganese oxide (NMO) reaction condition such as L/D the starting time of the NMO feed, feed rate, and flow rate of simulated flue gas, and NMO size were tested. The results showed that optimum L/D was 1.0 in this moving bed system. The higher the feeding rate was the higher the SO2 removal efficiency was and the higher the flow rate of simulated flue gas was the shorter the time to reach the euqilibirum concentration was. The final SO2 con-centration when it reaches the equilibrium concentration was not affected by the starting time of the NMO feed.

• 한국식품영양학회지
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• 제4권2호
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• pp.141-148
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• 1991

In order to Investigate the extraction mechanism of barley tea in cylindrical packed column, pilot plant scale packed column was designed and constructed. And extraction conditions for steady flow in the packed column were searched. The main results of this study are as follows ; 1. Circulation of the stock barley tea before the extraction running was indispensable In consideration of inequality, gas, particles existed in packed bed. Solid-liquid equilibrium was initially maintained after the circulation. 2. Flow direction of solvent must be up-flow for maintaining the constant bed height and flow rate during the extraction. Paessure drop in pucked bed was similar to decrease ratio of extract concentration. 3. The porosity of packed bed was in the range of 0.24∼0.36 according to the particle sloe. And it was decreased as the particle size became smaller.

• Journal of Biosystems Engineering
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• 제24권1호
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• pp.31-40
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• 1999

The objective of this study were to develop a cooling simulation model for fixed-bed of rough rice and to analyze the factors affecting cooling time of rough rice. A computer simulation model based on equilibrium conditions between grain and air was developed to predict temperature and moisture content changes during cooling of rough rice. the result of t-test showed that there were no significant differences between predicted and measured temperature changes on significance model agreed well with measured values. This cooling simulation model was applied to analyze the effect of some factors, such as air flow rate, cooling air temperature and humidity, initial grain temperature and moisture content, and bed depth, on cooling time of rough rice. Cooling rate increased with increase of air flow rate and bed depth whereas it decreased with increase of cooling air temperature and humidity and initial grain temperature. Among these factors, the most important factor was air flow rate. Specific air flow rate of 0.35㎥/min㎥ was required for cooling rough rice in 24 hours.

• 한국수자원학회논문집
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• 제42권5호
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• pp.425-432
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• 2009

공릉2보는 농업용수의 공급을 위하여 1970년대에 설치되었다. 그러나 인근 지역의 토지 이용의 변화로 용도를 다하여 사용되지 않고 방치되어 있었다. 공릉2보는 높이 1.5 m의 소형 보 이며, 공릉천의 하상재료는 가는 모래에서 가는 자갈로 구성되어있다. 지자체와 지역 주민들과의 협의를 통하여 공릉2보는 2006년 4월 14일 완전히 철거되었다. 본 논문에서는 공릉2보 철거에 따른 하천형태학적인 변화를 조사하기 위한 연구를 수행하였다. 보 철거 전 후의 하상재료의 입도분포, 종단 하상고, 그리고 단면형의 변화가 고찰되었다. 보를 포함한 1 km 구간에서 순 퇴적량이 산정되었으며, 결과로부터 평형하상을 유도하는 유사이동 과정이 초반 45일동안 무척 빠르게 진행되었음을 보였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제10권3호
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• pp.280-283
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• 2005

The adsorption of a model protein bovine serum albumin (BSA) in expanded bed chromatography was undertaken by exploiting a commercially available expanded bed column (20 mm i.d.) from UpFront Chromatography and Streamline DEAE $(\rho=1.2g/cm^3)$ from Amersham Pharmacia Biotechnology. The influence of whole yeast cells on the adsorption capacity of column was explored by employing yeast cells in a concentration ranged of 0 to $15\%(w/v)$. Equilibrium isotherms for adsorption of BSA on Streamline DEAE were correlated by using Langmuir equation. The presence of yeast cells resulted in decreased of BSA binding capacity in both batch binding and expanded bed chromatography. Results indicated that the yeast cells act as competitor for proteins to bind to the sites on adsorbents.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.770-775
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• 2001

Effects of magnetic field and carrier gas velocity on the magnetic separation of FCC catalyst by a high gradient magnetic separator were studied. The activities of the equilibrium catalyst, the magnetic particles and the nonmagnetic particles were evaluated in a fixed bed microreactor The results showed that heavy metal contaminated catalyst can be selectively separated by means of high gradient magnetic separation at magnetic field 0.5T and carrier gas velocity 0.3m.s$^{-1}$ , and lightly metal contaminated catalyst retained high catalytic activity.

• Korean Journal of Hydrosciences
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• 제1권
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• pp.15-25
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• 1990

Spatially varied unsteady flow in a groave-like channel of a sloping roof is analyzed by numerical solution of Saint Venant equations. Depth variations are discussed with different slopes and bed roughness of the channel. Time to equilibrium is found to be inversely proportional to the kinematic flow number. The design of roof drainage system by different schemes is included.