• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.6
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• pp.1487-1493
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• 2008

In order to investigate the cooling capacity of multi-heat pump applying an inverter compressor, the experiment on the cooling performance characteristics of heat pump with 3 indoor units was performed under the cooling standard and cooling low-temperature conditions. The system data were measured by the psychrometric calorimeter. The operation characteristics and the behavior of the cooling cycle of the heat pump with 3 indoor units were understood from the cooling capacity, COP, and P-h diagram by indoor-unit combination. The operating load and performance of the multi-heat pump depends on the indoor-unit combination. The cooling capacity and COP of the low temperature condition were larger than those of the standard one. Also the cycle was analyzed by using P-h diagram.

• Journal of the Korean Vacuum Society
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• v.15 no.1
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• pp.14-23
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• 2006

The scroll pump is widely used in ultra clean vacuum systems. However, there is no commonly available information on the hydrogen pumping characteristics of this pump, which creates a difficulty in determining whether the scroll pump can be used or not in a fusion experiment system where hydrogen ,is the main working gas. In this paper the experimental setup, measurement procedures, experimental results, and discussions on the pumping speed, the maximum compression ratio and the back-streaming properties of the scroll pump, especially for the hydrogen gas, are reported.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.672-677
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• 1998

액체금속로 순환 냉각재인 전기전도성 나트륨 유체를 전자기적으로 구동시키는 선형유도 전자펌프의 유로내 과기유체역학적(MHD) 특성 분포를 해석적으로 계산하였다. 유로 내 반지름 방향의 좌표에 따라 유속, 점성력 및 전자기 구동력 둥을 계산하여 하트만 수(H$_{a}$ )에 따른 유체 특성의 변화를 그래프로 도시하였다. 하트만 수(H$_{a}$ )가 증가할수록 도전성 나트륨 유체의 유속 분포는 점점 평탄해지고 점성력은 전자기력에 비해 무시할 정도로 작은 값을 가짐을 알 수 있었다. 따라서 적지 않은 자기장에 의해 구동되는 전자펌프에 있어서 금속 유체는 마치 일정 두께의 금속 고체로 취급될 수 있음을 예측할 수 있었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.34-37
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• 2010

One dimensional transient analysis was studied for turbopump-fed liquid propellant rocket engine(LRE) system in starting using AMESim. The effects of timing of gas generator fuel valve opening and gas generator ignition to start-up stability were researched for open cycle type system using LOX/RP-1 to propellants. Result show that the parameters and sequence on start-up should be considered to design optimized turbopump-fed LRE system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.302-307
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• 2007

In this paper, a flap valve micropump with an ionic polymer-metal composite (IPMC) actuator was designed, fabricated, and experimentally characterized. A multilayered IPMC based on Nafion/layered silicate and Nafion/silica nanocomposites was fabricated for the actuation section of the micropump. The IPMC diaphragm, a key element of the mircopump, was designed so that the IPMC actuator was supported by a flexible polydimethylsiloxane (PDMS) structure at its perimeter. This design feature enabled a significantly high displacement of the IPMC diaphragm. The overall size of the micropump is $20{\times}20{\times}5$ ${mm}^3$. Water flow rates of up to 760 ${\mu}l$/min and a maximum backpressure of 1.5 kPa were recorded. A significant advantage of the proposed micropump is its low driven voltage from only 1-3 V. In addition, a simple and effective design, and an ease of manufacturing are other advantages of the present micropump.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.4
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• pp.500-506
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• 2012

A method to model left ventricular assist device (LVAD) and detect suction occurrence for safe LVAD operation is presented. An axial flow blood pump as a LVAD has been used to assist patient with heart problems. While an axial flow blood pump, a kind of a non-pulsatile pump, has relative advantages of small size and efficiency compared to pulsatile devices, it has a difficulty in determining a safe pump operating condition. It can show different pump operating statuses such as a normal status and a suction status whether suction occurs in left ventricle or not. A fuzzy subtractive clustering method is used to determine a model of the axial flow blood pump with this pump operating characteristic and the developed pump model can provide blood flow estimates before and after suction occurrence in left ventricle. Also, a fuzzy subtractive clustering method is utilized to develop a suction detection model which can identify whether suction occurs in left ventricle or not.

• Journal of the Korean Vacuum Society
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• v.16 no.6
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• pp.405-413
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• 2007

Effect of design factors on the performance of vacuum system was simulated for optimum design of system. In this investigation, the feasibility of modelling mechanism for $VacSim^{Multi}$ simulator was proposed. Simulation results of pumping design factor showed the possibilities of simulation fore-study for the detailed design factors. Simulation of roughing pump presented the expected pumping behaviors based on the specifications of commercial pump. Application of booster pump exhibited the high pumping efficiency for middle vacuum range. Combinations of optimum backing pump for diffusion and turbo vacuum system were obtained. And, the characteristics of process application of both systems were also acquired.

• Journal of Power System Engineering
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• v.3 no.4
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• pp.45-50
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• 1999

기포 펌프는 물과 공기 사이의 접촉 면적을 증가시켜 공기로부터 물로의 산소 용해를 높이는 기능을 가지고 있다. 이 연구에서는 기포 펌프에서 여러 가지 흐름 패턴을 설정하고, 이것을 근거로 하여 슬립모델을 확립하여, 기포 펌프의 산소 용해 특성을 조사하였다. 이 연구에서 수행한 실험 결과로부터, 산소 전달 계수는 흐름 패턴(기포 흐름, 기포-슬러그 흐름, 슬러그 흐름)에는 상당한 영향을 받았으나, 시료수의 오염 정도에 따른 영향은 그다지 크지 않음을 확인하였다. 그리고, 산소 전달양은 레이놀즈 수에 비례하여 증가하며, 산소 전달면을 증가시키기 위해서는 에어 스톤이나 디퓨저의 이용이 매우 효과적임을 확인하였다. 또한, 표면 활성 물질은 물의 오염 정도나 흐름 패턴에 관계없이 산소 전달에 큰 영향을 미침을 알 수 있었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.167-170
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• 2006

For a short time a pyre-starter should turn the blades of a turbine to the adequate rotational speed by a single operation. Through this process the pressures of the components of a propellant rise rapidly up to the operating point, and the components enter into a gas-generator. Combustion in the gas-generator occurs to keep the turbopumps working. In this research characteristic parameters of a pyre-starter which correspond to the required performance of the turbopump before the gas-generator starts to work were selected

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.161-165
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• 2002

인류가 직면한 환경 및 에너지 문제를 타개하기 위한 많은 연구 중 흡수식 열펌프는 환경친화적인 자연냉매를 사용하는 열구동 시스템으로 다시 주목을 받고 있다. 흡수식 열펌프의 구성요소 중 흡수기는 암모니아의 흡수에 의한 열 및 물질전달 현상이 동시에 일어나는 곳으로 암모니아-물 열펌프 시스템의 성능 향상을 위해 가장 중요한 부분이다.(중략)