• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.371-374
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• 2005

We accomplished optimization for pump and treat (P&T) designs in consideration of degradation processes such as retardation and biodegradation, which are significant for contaminant fate in hydrogeology. For more desirable remediation, optimal pumping duration and minimum pumping rate constraint problems are studied. After a specific P&T duration, it replaces the P&T with the enhanced natural attenuation (ENA), which induces aerobic biodegradation by maintaining oxygen concentration. The design in this strategy carries out the optimization for the number and locations of oxygen injection wells.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.196-199
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• 2003

Characteristics of a heater-triggered switch has been analyzed through the simulations and experiments. It was for the charging of Bi-2223 double pancake load with 1.7 mH and two heaters were used. The timing of the sequential control and the heating current with two heaters are important factors to generate pumping-current. The thermal analysis of the switch considering the heater input and time was carried out. Based on the analysis just mentioned. heater-triggered switch was fabricated. Characteristic analysis was carried out through two modes having different sequential timing controls. Maximum pumping-current reached 18 A and the pumping rate was 113 mA/s at that time.

• 한국농공학회지
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• 제42권
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• pp.1-8
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• 2000

To examine the irrigation water uses in Sunjin river basin, existing status and operation records of headworks facilities including reservoirs, pumping stations, tube wells, and diversion dams were surveyed and analyzed for the period of 1994∼1998. Daily irrigation demand and water use were estimated for the irrigated paddy field using penman equation, Thank model, reservoir water balance model and daily pumping rate of pumping stations. Irrigation water use from multi-purpose dams in the basin was not included in this study.

• Journal of Korean Vacuum Science & Technology
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• 제7권2호
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• pp.27-32
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• 2003

A large cryo-pumping system composed of 4 cryosorption pumps was designed and manufactured to satisfy the pressure requirements of the NBI test stand. The cryosorption pump consists of a thermal shield/baffle assembly and a cryopanel coated with activated carbon granules. The thermal shield is cooled by liquid nitrogen, and the cryopanel by a commercial helium refrigerator. The operation characteristics and vacuum performance of the cryosorption pump were investigated. The cooling down time of the cryopanel to 20 K was about 6 hours with a liquid nitrogen consumption rate of about 35 L/hr. The maximum pumping speed of the cryosorption pump for the hydrogen gas measured by the steady pressure method was about 90,000 L/s.

• 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.

• 한국정밀공학회지
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• 제27권10호
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• pp.84-92
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• 2010

In this study a numerical analysis has been conducted for the flow characteristics and pumping performance of a piezoelectric-based micropump with electromagnetic resistance exerted on electrically conducting fluid. Here, electromagnetic resistance is alternately applied at the inlet and outlet with alternately applied magnetic fields in association with the reciprocal membrane motion of the piezoelectric-based micropump. A model of Prescribed Deformation is used for the description of the membrane motion. The internal flow characteristics and pumping performance are investigated with the variation of magnetic flux density, tube size, displacement of membrane and the frequency of the membrane. It turns out that the current micropump has a wide range of pumping flow rate compared with diffuser-nozzle based micropumps.

• 대한기계학회논문집A
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• 제28권4호
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• pp.378-385
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• 2004

Viscous-driven pumping is a very promising type in microscale applications. However, there exist a few disadvantages such as low efficiency and small volume flow rate. In the present study, a pump with tandem rotating cylinders and its optimum synthesis are proposed fur enhancing pumping performance. First, using an unstructured grid CFD method, we investigate the effects of geometrical parameters and then the performance of the pump with tandem cylinders is evaluated. Next, an optimum design synthesis tool is constructed by combining the aforementioned CFD analysis model with the mathematical optimization model, namely, Modified Method of Feasible Directions (MMFD). This technique is used to optimize the geometrical parameters of the pump, fur maximizing pumping efficiency. From the optimization results, it is believed that the present optimum synthesis is robust and has a potential fur other microfluidic device design.

• 설비공학논문집
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• 제21권1호
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• pp.33-40
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• 2009

In the present experimental study, the pumping performances of diffuser/nozzle based piezoelectric micropumps are estimated with different operating factors and geometries. Here, the effects of the input voltage and frequency on the pumping performances have been examined together with the influences of the positions of the inlet and outlet. The results show that the flow rate of the micropump is larger with larger input voltage with the largest flow rates for the frequency to be close to 6.0 Hz all through the current experimental study. Also, it has been found that the positions of the inlet and outlet affect much on the performance of the piezoelectric micropumps. Error estimation has been carried out for the evaluation of the pumping performance in association with the uncertainty of the measurement.

• 한국산학기술학회논문지
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• 제16권2호
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• pp.1364-1369
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• 2015

반도체 칩의 고집적화로 과거 와이어 본딩 공정에서 BUMP 공정으로 전환되면서 반도체칩과 외부 기기로 이어지는 통신선도 더욱 미세해짐으로 인해 보다 정밀한 작업이 필요한 실정이지만 PSPI의 고점도 특성상 정량제어가 어렵고 버블유입에 따른 수율의 저하가 계속되고 있는 실정이다. 따라서 본 논문에서는 반도체 BUMP 공정에서 고점도 감광성 폴리이미드(PSPI : Photosensitive Polyimide)의 도포(coating)시 발생하는 기포(gas)를 제거하여 공급하는 D&P(Degassing and Pumping) 시스템을 개발하였다.

• Geomechanics and Engineering
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• 제32권4호
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• pp.387-396
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• 2023

Ground subsidence, which is a current concern that affects piled raft foundations, has occurred at a high rate in Ho Chi Minh City, Viet Nam, due primarily to groundwater pumping for water supply. In this study, the groundwater level (GWL) change affect on a piled raft foundation was investigated based on the three-dimensional finite element method (3D-FEM) using the PLAXIS 3D software. The GWL change due to global groundwater pumping and dewatering were simulated in PLAXIS 3D based on the GWL reduction and consolidation. Settlement and the pile axial force of the piled raft foundation in Ho Chi Minh subsoil were investigated based on the actual design and the proposed optimal case. The actual design used the piled foundation concept, while the optimal case applied a pile spacing of 6D using a piled raft concept to reduce the number of piles, with little increased settlement. The results indicated that the settlement increased with the GWL reduction, caused by groundwater pumping and dewatering. The subsidence started to affect the piled raft foundation 2.5 years after construction for the actual design and after 3.4 years for the optimal case due to global groundwater pumping. The pile's axial force, which was affected by negative skin friction, increased during that time.