• 대한기계학회논문집B
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• 제30권8호
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• pp.722-730
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• 2006

In this study, the flow characteristics of a FPN (Fountain Pen Nano-Lithography) using active membrane pumping are investigated. The FPN has integrated chamber, micro channel, and high capacity reservoir for continuous ink feed. The most important aspect in this probe provided control of fluid injection using active membrane pumping in chamber. The flow rates in channel by capillary force are theoretically analyzed, including the control of the mass flow rates by the deflection of the membrane. The above results are compared with the numerical simulations that calculated by commercial code, FLUENT. The velocity of the fluid in micro channel shows linear behaviors. And the mass flows are proportional to the second order function of the pumping pressure that is imposed to the membrane.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.922-929
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• 2006

In this study, flow characteristics of the FPN (Fountain Pen Nano-Lithography) using active membrane pumping are investigated. This FPN has integrated chamber, micro channel, and high capacity reservoir for continuous ink feed. The most important aspect in this probe provided control of fluid injection using active membrane pumping in chamber. The flow rates in channel by capillary force are theoretically analyzed, including the control of mass flow rates by deflection of membrane. The above results are compared with numerical simulations that calculated by commercial code, FLUENT. The velocity of fluid in micro channel shows linear behaviors. And the mass flows are proportional to the second order function of pumping pressure that is imposed to membrane.

• International Journal of Aeronautical and Space Sciences
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• 제12권1호
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• pp.69-77
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• 2011

A peristaltic micropump with lightweight piezo-composite actuator (LIPCA) membrane valves is presented. The micropump contained three cylinder chambers that were connected by microchannels and two active membrane valves. A circular miniature LIPCA was developed and manufactured to be used as actuating diaphragms. The LIPCA diaphragm acted as an active membrane valve that alternate between open and closed positions at the inlet and outlet in order to produce high pumping pressure. In this LIPCA, a lead zirconium titanate ceramic with a thickness of 0.1 mm was used as an active layer. The results confirmed that the actuator produced a large out-of-plane deflection. During the design process, a coupled field analysis was conducted in order to predict the actuating behavior of the LIPCA diaphragm; the behavior of the actuator was investigated from both a theoretical and experimental perspective. The active membrane valve concept was introduced as a means for increasing pumping pressure, and microelectromechanical system techniques were used to fabricate the peristaltic micropump. The pumping performance was analyzed experimentally in terms of the flow rate, pumping pressure and power consumption.

• 한국방사선학회논문지
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• 제11권2호
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• pp.157-165
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• 2017

본 논문에서는 고에너지 엑스선(6MeV)을 조사한 세포막 모델에서 $K^+-Na^+$ pump 시스템의 능동적 전달특성에 대하여 연구하였다. 이 실험에 사용된 세포막 모델은 $Na^+$슬폰화 폴리스티렌-디비닐벤젠(polystyrene-divinylbenzene) 혼성 중합막을 사용하였다. 이온의 초기플럭스는 $H^+$이온 농도의 증가와 함께 증가하였다. 이 실험의 조건을 pH 1.5-5, 온도 $36.5^{\circ}C$로 하여 첫 번째, 방사선이 조사되지 않은 막에서 $K^+$의 초기플럭스는 $2.09{\times}10^{-4}-1.32{\times}10^{-3}mole/cm^2{\cdot}h$이고 $Na^+$의 초기플럭스는 $7.09{\times}10^{-4}-1.09{\times}10^{-3}mole/cm^2{\cdot}h$으로 나타내었다. 두 번째, 방사선이 조사된 막에서 $K^+$의 초기플럭스는 $21.0{\times}10^{-4}-16.7{\times}10^{-3}mole/cm^2{\cdot}h$이고 $Na^+$의 초기플럭스는 $62.0{\times}10^{-4}-20.6{\times}10^{-3}mole/cm^2{\cdot}h$으로 나타내었다. 막의 $K^+/Na^+$선택도는 약 1.10이다. 조사된 막의 pH의 추진력은 조사되지 않은 막보다 약 9-20배 정도 유의성 있게 증가하였다. 세포막모델에서 $K^+-Na^+$의 pump 시스템의 능동적 전달특성이 비정상적이기 때문에 세포장해가 세포에서 발현된다고 사료된다.

• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.41-55
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• 2018

General polymer electrolyte fuel cell (PEMFC) operates at less than $80^{\circ}C$. Therefore liquid phase water resulting from electrochemical reaction accumulates and floods the cell which in turn increases the mass transfer loss. To prevent the flooding, it is common to employ serpentine flow channel, which can efficiently export liquid phase water to the outlet. The major drawback of utilizing serpentine flow channel is the large pressure drop that happens between the inlet and outlet. On the other hand, in the high temperature polymer electrolyte fuel cell (HT-PEMFC), since the operating temperature is 130 to $180^{\circ}C$, the generated water is in the state of gas, so the flooding phenomenon is not taken into consideration. In HT-PEMFCs parallel flow channel with lower pressure drop between the inlet and outlet is employed therefore, in order to circulate hydrogen and air in the cell less pumping power is required. In this study we analyzed HT-PEMFC's different flow channels by parallel computation using previously developed 3-D isothermal model. All the flow channels had an active area of $25cm^2$. Also, we numerically compared the performance of HT-PEMFC parallel flow channel with different manifold area and Rib interval against the original serpentine flow channel. Results of the analysis are shown in the form of three-dimensional contour polarization curves, flow characteristics in the channel, current density distribution in the Membrane, overpotential distribution in the catalyst layer, and hydrogen and oxygen concentration distribution. As a result, the performance of a real area fuel cell was predicted.