• Journal of Hydrogen and New Energy
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• v.15 no.3
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• pp.175-186
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• 2004

In this paper, we developed the dynamic model of a fuel cell system suitable for controller design and system operation. The transient phenomena captured in the model include the flow characteristics and inertia dynamics of the compressor, the intake manifold filling dynamics, oxygen partial pressures and membrane humidity on the fuel cell voltage. In the simulations, we paid attention to the transient behavior of stack voltage and compressor pressure, stoichiometric ratio. Simulation results are presented to demonstrate the model capability. For load current following, stack voltage dynamic characteristics are plotted to understand the Electro-chemistry involved with the fuel cell system. Compressor pressure and stoichiometric ratio are strongly coupled, and independent parameters may interfere with each other, dynamic response, undershoot and overshoot.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.502-503
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• 2008

The modelling of PEMFC(Proton Exchange Membrane Fuel Cell) has been studied in many kinds of methods. But there are some limitations in application of the developed models to analysis transient phenomena of power systems. The PSCAD/EMTDC is very popular simulation tool in power system areas. To analysis power systems interconnected to PEMFCs, the PSCAD/EMTDC model of the PEMFCs is needed. In this paper, we developed a PSCAD/EMTDC model of PEMFC based on electro-chemical characteristic equations of PEMFC. Also, we performed simulations using the developed model in the PSCAD/EMTDC program and tested appropriateness of the proposed the models. The simulations showed good results.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.460-465
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• 2003

The modeling of PEM (Proton Exchange Membrane) fuel cell system consisting of fuel cell stack and BOP (Balance of Plant) is presented in this paper. The effects of temperature, pressure (air, hydrogen), and humidity on the fuel cell system performance were mainly investigated using thermo-dynamical and electro-chemical equations. To understand the power distribution characteristics of fuel cell system, the effects of operating temperature and air pressure on maximum power and system power were also demonstrated. Through this study, we can get the basic insight into the fuel cell stack and BOP component sizing and it can be used effectively for the optimization of the practical fuel cell systems in purpose.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.9
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• pp.1563-1571
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• 2008

In this paper, dynamics modeling of a PEMFC is performed by electro-chemical equations. The developed PEMFC simulation model is implemented using MATLAB Simulink in order to design an optimal PCS for fuel cell systems. In addition, by use of the developed model as an input source of PCS, the validity of the proposed dynamic characteristic model of the PEMFC is verified by various simulation and experimental results.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.17-20
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• 2008

Cold start of a fuel cell system is a major obstacle should be overcome as to commercialize it, especially for passenger vehicle applications. However, the cold start characteristics is so complicated since it involves various phenomenon such as ice-blocking in GDL, ionic conductivity in membrane affected by water activity with phase change, heat transfer through components such as bipolarplates or endplates, electro-chemical reactions affected by circumferential temperature and humidity as well. Axiomatic design provides a systematic method to investigate the complex phenomenon although it was developed as a methodology to establish logical design procedure by Nam P. Suh in 1990s. This paper presents a framework to approach the complex cold start problem using Axiomatic Design which features simplifying a problem through hierarchical decomposition and decoupling from the view of functional requirements and design parameters.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.12 s.255
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• pp.1228-1235
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• 2006

PEMFC(Proton Exchange Membrane Fuel Cell) is a low temperature fuel cell and has many probabilities of commercial use. However, water management is one of the serious technical problems for commercialization. It is necessary to understand the relationship between operation conditions and water behavior in PEMFC channel because it affects fuel cell performance. In this paper, the distribution of current density according to inlet humidity condition is mainly observed and discussed. If the anode inlet is well humidified, electro-osmotic drag is very active. For this reason, current density is very high at inlet side and the distribution is non-uniform.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2788-2793
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• 2008

A numerical analysis has been conducted for flow characteristics and performance of a micropump with piezodisk and MHD(Magnetohydrodynamics) fluid. Various micro systems which could not be considered in the past have been recently growing with the development of MEMS(Micro Electro Mechanical System) and micro machining technology. Especially, micropumps, essential part of micro fluidic devices, are being lively studies by many researchers. In the present study, the piezo electric micropump with electromagnetic resistance for electrically conducting fluids is considered. The prescribed grid deformation method is used for the displacement of the membrane. The change of the performance of the micropump and flow characteristics of the electrically conducting fluid with the magnitude of the magnetic fields, duct size, the position of the inlet and outlet duct are investigated in the present study.

• Proceedings of the KIEE Conference
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• 2008.11b
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• pp.89-91
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• 2008

Organic EL has been expected to adopt to a new styles of technology that make flat display after Tang & Vanslyke made good electric luminescence device in late 1980s. Their studies based on multi layer structure that consists of emitting layer and carrier transporting layer using proper organic material. But oxidization of organic layer by ITO, energy walls in both pole interface, contaminations of ITO surface, importance of protecting membrane, diffusive dimming of light to cathode organic layer, these causes of degradations are common facts of a macromolecule and micro molecule. We think these degradation caused by the impact of heat and electro-chemical factor, bulk effect and interface phenomenon, and raise a question.

• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.110-113
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• 2002

Organic EL has been expected to adopt to a new styles of technology that make flat display after Tang & Vanslyke made good electric luminescence device in late 1980s. Their studies based on multi layer structure that consists of emitting layer and carrier transporting layer using proper organic material. In this study. we made multi layer device using $Eu(TTA)_3(phen)$ as a luminescence material by PVD and investigate luminous properties of each device. But oxidization of organic layer by ITO. energy walls in both pole interface. contaminations of ITO surface, importance of protecting membrane, diffusive dimming of light to cathode organic layer. these causes of degradations are common facts of a macromolecule and micromolecule. We think these degradation caused by the impact of heat and electro-chemical factor, bulk effect and interface phenomenon. and raise a question.

• Proceedings of the KIEE Conference
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• 2006.07c
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• pp.1414-1415
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• 2006

Air-gap type film bulk acoustic wave resonator device using ZnO for piezoelectric layer and sacrifice layer, deposited by RF magnetron sputter with various conditions, fabricated in this study. Also, membrane$(SiO_2)$ and top and bottom electrode(both Al) of piezoelectric layer deposited by RF magnetron sputter. Using micro electro mechanical systems(MEMS) technique, sacrifice layer removed and then air-gap formed. The results of each process checked by XRD, AFM, SEM to obtain good quality device.