• 한국산학기술학회논문지
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• 제6권2호
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• pp.202-209
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• 2005

경사 열사이폰 열교환기는 잠열을 이용한 대량의 열수송 능력과 증기류의 열확산에 의한 온도 분포의 균일화, 경량, 간단한 구조, 빠른 열응답 특성 등의 우수성을 가지고 있다. 본 연구에서는 이와 같은 우수성을 보유하고 있는 경사 열사이폰 열교환기에 대하여 경사각의 변화, 작동유체의 종류, 열유속 및 내부압력 등 열사이폰의 작동에 관련된 변수들에 관하여 열전달 성능을 실험적으로 연구하였다. 평관형 및 마이크로 그루브형 경사 열사이폰에서 실험적인 연구를 수행한 결과, 마이크로 60그루브형으로 경사각이 $30^{\circ}$이고 작동유체가 증류수인 경우 비등열전달계수는 $15000\;W/m^3K$으로 나타났으며, 이 간은 평관형 경사 열사이폰의 비등열전달계수보다 1.6배 정도 높게 나타났다. 그리고 작동유체가 증류수인 경우 평관형 열사이폰에서 비등열전달계수는 경사각이 $25^{\circ}{\sim}30^{\circ}$ 범위에서, 메탄올과 에탄올에서는 경사각이 $20^{\circ}{\sim}25^{\circ}$ 범위에서 최대 비등열전달계수를 나타났다. 또한 평관형 열사이폰은 경사각이 $25^{\circ}{\sim}30^{\circ}$범위에서, 마이크로 그루브형 열사이폰은 경사각이 $20^{\circ}{\sim}25^{\circ}$사이에서 최대 비등열전달 성능을 나타내었다.

• Tuberculosis and Respiratory Diseases
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• 제61권5호
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• pp.456-462
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• 2006

연구배경: 대량 흉수의 가장 흔한 원인은 악성으로 알려졌으나 이에 대한 보고가 많지 않고, 지역 및 시대에 따라 다른 분포를 보였다. 저자들은 결핵의 유병율이 높은 국내에서 대량 흉수의 원인 질환의 분포를 알아보고, 원인 질환 감별을 위한 흉수의 분석지표에 대해 알아보기 위해 연구를 시행하였다. 방 법: 2002년 7월부터 2005년 7월까지 한양대학교 구리병원에 입원하여 흉수 천자를 시행하였던 298명 환자를 대상으로 후향적 조사를 시행하였다. 대량 흉수는 흉부단순촬영에서 일측 흉곽의 2/3 이상을 차지한 경우로 정의하였고 각 환자에서 혈청 생화학 검사, 흉수 천자 소견을 비교하였다. 결 과: 전체 298명의 흉수 예 중 대량 흉수는 41예, 13.8% 이었다. 대량 흉수의 원인으로는 악성 흉수가 19예(46.3%)로 가장 많았고 결핵 15예(36.6%), 부폐렴성 흉막염 및 농흉 4예(9.8%), 여출성 흉수 3예(7.3%) 순이었다. 대량 흉수 중 악성 흉수(n=19)와 양성 흉수군(n=22)의 비교 시 악성 흉수에서 ADA가 낮고(30.5 vs 86.2;p=0.017), amylase 수치가 높았다(349.0 vs 39.2;p=0.031). 흉수 적혈구는 악성 흉수 군에서 높은 경향을 보였다(95,406 vs 22,105;p=0.052). 결 론: 국내에서 대량 흉수의 원인으로는 악성 외에도 결핵에 의한 경우가 많았으며, ADA가 낮은 혈성 흉수는 악성을, ADA가 높은 림프구성 흉수는 결핵의 가능성을 고려해 볼 수 있겠다.

• Journal of the korean society of oceanography
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• 제31권4호
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• pp.173-182
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• 1996

A median-density fluid was injected into the upper layer of a two-layered fluid in a rotating cylindrical container. Several sets of the top and bottom boundary configurations were employed and the flow pattern of each layer including the injected fluid was observed to determine the factors that affect the path of the injected intermediate fluid. The axisymmetric path of the intermediate fluid when the upper layer had a free surface, changed into the asymmetric path with bulged-shape radial spreading whenever either the upper layer or the lower layer had ${\beta}$-effect. The internal Fronds number that controls the shape of the interface turned out to be the most important parameter that determines the radial spreading in terms of location and strength. When the upper and lower layer had the ${\beta}$-effect, convective overturning produced anticyclonic vortices at the frontal edge of the intermediate fluid, and that could enhance the vertical mixing of different density fluids. The intermediate fluid did not produce any topographic effect on the upper-layer motion during its spreading over the interface, since its thickness was very small. However, its anticyclonic motion within the bulged-shape produced a cyclonic motion in the lower layer just beneath the bulge.

• 동의생리병리학회지
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• 제24권5호
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• pp.843-847
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• 2010

Wikyung-Tang(WKT) is herbal medication used in abcess-causing respiratory disease. Previous in vitro study demonstrates that WKY presents anti-proliferative effects in A549 cells. Here we show that WKY protects mice against lipopolysaccharide(LPS)-induced acute lung injury (ALI). We pretreated mice orally with WKY(2.34 and 5.85 g/kg body weight) 1, 24 and 48 hours before intratracheal administration of LPS. For same condition, control group was pretaken orally distilled water before LPS administration. 24 hours after LPS intratracheal instillation, bronchoalveolar lavege fluids(BALF) was obtained to measure protein and proinflammatory cytokines(TNF-${\alpha}$, IL-$1{\beta}$, IL-6). Protein and proinflammatory cytokines in BALF of WKT treated groups were totally decreased. Statistically, Protein, TNF-${\alpha}$ and IL-$1{\beta}$ of high concentrate WKT treated group decreased significantly compared with control group. In conclusion, WKY had some anti-inflammatory effect in a clinically relevant model of ALI. these results indicated that WKY was effective in inhibiting ALI and might act as a potential therapeutic reagent for treating ALI in the future.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.55-59
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• 2005

CFD analysis has been conducted to find the two stage impeller configuration which is the most suitable for a stirred tank with an internal helical cooling coil and a cooling jacket, which is frequently used in chemical industries for highly exothermic reactions ranged from low to medium viscosity. Two typical types of impellers are considered; pitched paddle impellers and Rushton turbine impellers. Interestingly, pitched paddle impellers show a good mixing performance for multi-species, whereas Rushton turbine impellers achieve a good mixing performance for multi-phases. Besides the type of an impeller, the location of an impeller is another important factor to be considered in order to accomplish an effective mixing. The best set of types and locations of two impellers is recommended based on the coefficient of variation(CoV) value and the heat removal capability obtained from CFD results. The former is a measure to quantify the degree of mixing.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.235-238
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• 2005

The unsteady supersonic flow over two- and three-Dimensional cavities has been analyzed by the integration of unsteady Reynolds-Averaged Navier-Stokes(RANS) with the k - w turbulence model. The unsteady flow is characterized by the periodicity due to the mutual relation between the shear layer and the internal flow in cavities. Numerical method is upwind TVD scheme based on the flux vector split with the Van Leer limiters, and time accuracy is used explicit 4th stage Runge-Kutta scheme. Cavity flows are Comparison of two- and three-dimensional. The cavity has a L/D ratio of 3 for two-dimensional case. and same L/D and W/D ratio is 1 for three-dimensional case. The Mach and Reynolds numbers are held constant at 1.5 and 450000 respectively. For the three-dimensional case, the flow field is observed to oscillate in the 'shear layer mode' with a feedback mechanism that follow Rossiter's formula. On the other hand, the self-sustained oscillating flow transitions to a 'wake mode' for the two-dimensional simulation, with more violent fluctuations inside the cavity.

• 전기학회논문지
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• 제59권6호
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• pp.1087-1094
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• 2010

We have developed a cylindrical multi-terminal capacitive-conductive sensor that could be attached to the internal surface of cooling system pipe to evaluate capacitance and conductivity of heat transfer fluid. It was used as measuring system to diagnose insulating condition, by which was kept a insulating resistance of inner stack and at the same time was cooled electrochemical heat of reaction of FCEV(fuel cell electric vehicle) stack that used a compressed hydrogen gas reacting with oxygen in accordance with variation on thermal degradation of nonconductive heat transfer fluid. Also to assess diagnosis characteristics of heat transfer fluid, i.e. coolant, we have performed accelerated aging test using developed sensor attached to cooling system. Consequently, it was measured dielectric and electric resistance of coolant to estimate and analyse for dielectric properties by degradation condition.

• 설비공학논문집
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• 제15권2호
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• pp.144-151
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• 2003

An experimental study was carried out in a uniformly heated horizontal tube to examine heat transfer characteristics of pure refrigerants, R134a and R123, and their mixtures during flow boiling. The flow pattern was also observed through tubular sight glasses with an internal diameter of 10 mm located at the inlet and outlet of the test section. Tests were run at a pressure of 0.6 MPa and in the heat flux ranges of 5~100 kW/$m^2$, vapor Quality 0~100 percent and mass velocity of 150-600 kg/$m^2$s. The observed flow patterns were compared to the flow pattern map of Kattan et al., which predicted well the present data over the entire range of mass velocity employed in this study. Heat transfer coefficients of the mixture were less than the interpolated values between pure fluids both in the low quality region where the nucleate boiling is dominant and in the high quality region where the convective evaporation is dominant.

• 한국임상약학회지
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• 제26권3호
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• pp.264-266
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• 2016

A 21-year-old healthy Korean man worked on a building construction site every day for almost 2 months and exercised every day for 1 or 2 hours after working hard. He felt dizziness, nausea, and experienced vomiting and body aches immediately after exercise and immediately took cold medicines including acetaminophen, cimetidine, bepotastine, and Codenal? complex for the common cold symptoms for 2 days because he was scheduled to participate in navy training at that time. He complained of severe trapezius pain and aches in his left calf 3 days after joining the Navy training. Testing revealed creatine phosphokinase (CPK) 6260 U/L, myogloblin 176 mcg/L in the urine, liver enzymes increased, and oliguria, suggesting rhabdomyolysis. He recovered with intravenous fluids without any complications.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.236-242
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• 2007

A theoretical and numerical investigation is performed on the flow in a micronozzle for precision-controlled seal dispenser. The working fluid is a highly viscous epoxy used as sealant in producing LCD panels, which contains a number of tiny solid spacers. Flow analysis is conducted in order to achieve the optimal design oj internal geometry of a nozzle. A simplified design analysis methodology is proposed for predicting the flow in the nozzle based on the assumption that the Reynolds number is much less than O(1). The parallel numerical computations are performed by using a CFD package FLUENT. Comparison discloses that the theoretical model gives a good prediction on the distribution of pressure and wall shear stress in the nozzle. However, the theoretical model has a difficulty in predicting the maximum wall shear stress as found in a limited region near edge by numerical computation. The theoretical and numerical simulations provide the good guideline for designing a dispensing micronozzle.