• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.157-158
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• 2007

Effects of post-metallization anneal (PMA) on interface trap characteristics of Si-$SiO_2$ are studied. The conventional PMA method utilizes forming gas anneal, where 10% hydrogen in nitrogen atmosphere is used. A new PMA method utilizes hydrogen rich PECVD- silicon nitride $(SiN_x)$ film as a hydrogen diffusion source and a out-diffusion blocking layer. It can be shown through charge pumping current measurement that the new PMA is indeed effective to decrease Si-$SiO_2$ interface trap density.

• International journal of advanced smart convergence
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• 제4권1호
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• pp.104-113
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• 2015

This paper focuses on a temperature effects on a PV panel which has been installed in Thailand. The main objective is cleaning PV panels and reduce temperature of PV panel by water injects from waterway and experimental results of PV power what it is difference. This project is designed by PLC control system which water injects and control PV temperature, In addition, this project consists of hardware and software such as water pump, water injection and PLC control has been automatically and it can be control system manually. The automatic control system is working when PV temperature rises up over 45 degree Celsius after that the pumping machine would inject water to the surface of PV panels and it must be stop when the PV panel temperature comes down less than 45 degree Celsius. The result of actual experimental found that the control system has been done correctly under specify condition. The experimental has been shown electrical data before and after water injects on PV system found that the electrical power a bit increases and The energy has been taken from PV panel less than energy consumption equipment of control system which taken to operate the water injecting system.

• 한국지하수토양환경학회지:지하수토양환경
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• 제7권2호
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• pp.23-33
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• 2002

거물기초굴착을 위한 암반층의 지하수위를 효과적으로 낮추기 위하여 3개의 군정을 설치하고 인공수압파쇄를 실시한 결과 각 우물의 산출량은 29%, 42% 및 110% 증가하였으나, 동시험시 양수시 비양수량이 단정 양수시와 비교하여 추가 수위강하 효과에도 불구하고 모두 소폭으로 감소하여 3개 우물의 파쇄대가 수리적으로 서로 연결되었음을 확인하였다. 가장 먼 거리에 있는 기존의 지질구조(단열계) 방향으로 인공파쇄대가 가장 크게 확장되어 성공적으로 지하굴착을 수행할 수 있었다. 다른 사례로는 생활용수 양수량 증대를 목적으로 시행한 사례로 산출성이 약 28% 증대되었다.

• Spatial Information Research
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• 제7권1호
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• pp.103-117
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• 1999

도시지역에서 지하수 산출특성, 흐름 및 오염현상은 인위적인 양수, 지하구조물, 다양한 오염원 지면 포장으로 인한 지하수 함양의 국지적 변동 등의 영향을 받는 매우 복잡한 특성을 가진다. 서울지역 지하수시스템을 분석하기 위해 지리정보시스템 환경에서 수문지질학적 데이터베이스를 구축하였다. 지하수 수위변화의 주요인은 한강수계, 지하철 지형, 강우 등이고 이들을 이용하여 지하수시스템에 대한 영향을 분석하였다. 그리고 그 자료와 분석결과를 ARC/INFO에 데이터 베이스로 저장하고 실세계의 현상과 비구 분석하였다. 구축된 내용은 지하수 오염원의 분포, 대수층의 수리상수, 한강수위 변화에 대한 지하수 영향간 지하철 역사의 대규모 양수로 인한 지하수시스템의 변화 둥이다. 자료의 특성에 맞는 자료 형태로 저장하고 표현할 수 있도록 하였다.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1889-1896
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• 2003

In the microfluidic applications, viscous-driven pumping mechanism is a promising one since the viscous effect increases significantly as the size of device decreases, relative to the inertial effect. However, there exist a few drawbacks we have to improve such as low efficiency and small volume flow rate. In the present study, an optimum design synthesis is proposed to enhance the performance characteristics of the micropump with single rotating cylinder. First, the unstructured grid CFD method is described and validated by comparing its results to the previous results. Next, an automated optimum design synthesis tool is constructed by combining the aforementioned CFD analysis model with the mathematical optimization model. This technique is used to improve the performance characteristics of newly designed viscous-driven pump. The presented results show that the fluid dynamic optimization tool is robust and may be applied to other microfluidic device design applications.

• 한국물환경학회지
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• 제22권2호
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• pp.349-357
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• 2006

Nowadays, the discharges of urban streams during dry season are depleted because the hydrologic cycle in the watershed has been destroyed due to the expansion of the impermeable area, the excessive groundwater pumping, climate change, and so forth. The streamflow depletion may bring out severe water quality problems. This research are to investigate the hydrologic characteristics and to develop a technology to restore sound hydrologic cycle of Anyangcheon watershed. For the hydrological cycle analysis of the Anyangcheon watershed, continuous simulations of urban runoff were performed for the upstream basin of Gocheok bridge whose basin area covered 4/5 of the whole catchment area. The increase of impervious area by urbanization was analysed and its effect on urban runoff was evaluated. The SWMM 5 (Storm Water Management Model 5) was used for the continuous simulation of urban runoff. The analysis results of urbanization effect on runoff are as follows: the surface runoff in 2000 increases to 65% of the whole precipitation whereas the surface runoff in 1975 amounts to 50% of the precipitation; the groundwater runoff in 2000 amounts to 7% and shows 6% decrease during the period from 1975 to 2000.

• 한국분무공학회지
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• 제22권2호
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• pp.69-79
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• 2017

When designing a redox flow battery system, compression of battery stack is required to prevent leakage of electrolyte and to reduce contact resistance between cell components. In addition, stack compression leads to deformation of the porous carbon electrode, which results in lower porosity and smaller cross-sectional area for electrolyte flow. In this paper, we investigate the effects of electrode compression on the cell performance by applying multi-dimensional, transient model of all-vanadium redox flow battery (VRFB). Simulation result reveals that large compression leads to greater pressure drop throughout the electrodes, which requires large pumping power to circulate electrolyte while lowered ohmic resistance results in better power capability of the battery. Also, cell compression results in imbalance between anolyte and catholyte and convective crossover of vanadium ions through the separator due to large pressure difference between negative and positive electrodes. Although it is predicted that the battery power is quickly improved due to the reduced ohmic resistance, the capacity decay of the battery is accelerated in the long term operation when the battery cell is compressed. Therefore, it is important to optimize the battery performance by taking trade-off between power and capacity when designing VRFB system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.550-551
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• 2005

고밀도 유도결합 플라즈마 장치의 $O_2$ 방전에 대한 공간 평균 시뮬레이터를 제작하였다. 제작된 시뮬레이터는 $O_2$ 플라즈마 방전에서 발생되는 전자, 양이온, 음이온 및 중성종, 활성종들에 대해 공간 평균된 유체 방정식을 기반으로 하고 있으며, 고밀도 유도결합 플라즈마 장치에서 전자가열 모델은 anomalous skin effect 를 고려한 파워 흡수 모델을 적용하여 전자가 흡수하는 고주파 파워량을 결정하였다. 완성된 시뮬레이터에서 RF- 파워, gas-inlet, pumping-speed등의 조정 변수를 비롯한 여러 가지 장치 변수들의 변화에 대한 하전입자, 중성종, 활성종들의 밀도 변화 및 전자 온도 의존성을 계산하였다.

• Geomechanics and Engineering
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• 제28권5호
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• pp.437-454
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• 2022

The hydro-mechanical (HM) two-way sequential coupling in the TOUGH2-FLAC3D linking algorithm is validated completely and successfully in both M to H and H to M directions, which are initiated by mechanical surface loading for geomechanical validation and hydrological groundwater pumping for hydrogeological validation, respectively. For such complete and successful validation, a TOUGH2-FLAC3D linked numerical model is developed first by adopting the TOUGH2-FLAC3D linking algorithm, which uses the two-way (fixed-stress split) sequential coupling scheme and the implicit backward time stepping method. Two geomechanical and two hydrogeological validation problems are then simulated using the linked numerical model together with basic validation strategies and prerequisites. The second geomechanical and second hydrogeological validation problems are also associated with the Mandel effect and the Noordbergum and Rhade effects, respectively, which are three phenomenally well-known but numerically challenging HM effects. Finally, sequentially coupled numerical solutions are compared with either analytical solutions (verification) or fully coupled numerical solutions (benchmarking). In all the four validation problems, they show almost perfect to extremely or very good agreement. In addition, the second geomechanical validation problem clearly displays the Mandel effect and suggests a proper or minimum geometrical ratio of the height to the width for the rectangular domain to maximize agreement between the numerical and analytical solutions. In the meantime, the second hydrogeological validation problem clearly displays the Noordbergum and Rhade effects and implies that the HM two-way sequential coupling scheme used in the linked numerical model is as rigorous as the HM two-way full coupling scheme used in a fully coupled numerical model.

• KEPCO Journal on Electric Power and Energy
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• 제2권3호
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• pp.461-467
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• 2016

부유 이송식 해상풍력 기초를 목표 지점에 설치하기 위해서는 내부의 중공부에 해수를 주입하여 착저 시키게 되는데, 그 과정에서 중량 및 무게 중심과 부력중심이 변하게 되어 부유식 기초가 불안정해 질 수 있다. 부유 이송식 기초의 동적안정성 해석은 기초 외부의 수력학적 하중과 6-자유도 운동을 하게 되는 기초에 작용하는 파도와 조류 하중 및 설치 과정에서 기초 내부의 중공부로 투입되는 해수의 무게중심 이동까지 동시에 고려해야 하는 복잡한 문제이다. 따라서 본 연구에서는 3차원 비정상 CFD 기법과 다물체 동역학 기법을 연성 (coupling)한 정밀 해석기법을 적용하여 부유 이송식 기초 내부 물의 슬로싱 운동까지 고려한 동적안정성 해석을 수행하고 특성을 분석하였다.