• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.865-871
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• 2005

Submicron thick solid electrolyte membrane is essential to the implementation of low temperature solid oxide fuel cell, and, therefore, development of new electrode structures is necessary for the submicron thick solid electrolyte deposition while providing functions as current collector and fuel transport channel. In this research, a nickel membrane with multi-stage nano hole array has been produced via modified two step replication process. The obtained membrane has practical size of 12mm diameter and $50{\mu}m$ thickness. The multi-stage nature provides 20nm pores on one side and 200nm on the other side. The 20nm side provides catalyst layer and $30\~40\%$ planar porosity was measured. The successful deposition of submicron thick yttria stabilized zirconia membrane on the substrate shows the possibility of achieving a low temperature solid oxide fuel cell.

• Journal of the Korean Ceramic Society
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• v.43 no.12 s.295
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• pp.751-757
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• 2006

Recently, a new type of solid oxide fuel cells has been developed employing extremely thin oxide electrolyte. These fuel cells are expected to operate at significantly reduced temperature compared to conventional solid oxide fuel cells. Accordingly, they may resolve the stability and material selection issues of high temperature fuel cells. Furthermore, they may eliminate the limitations of polymer membrane fuel cells whose operation temperature is under $100^{\circ}C$. In this paper, we review the electrolytes for intermediate temperature operation. Then, we discuss the current development of thin film solid oxide fuel cells that possibly operated at low temperatures.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.51-54
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• 2008

This study aims to devise and analyze a power generation system combining the solid oxide fuel cell and oxy-fuel combustion technology. The fuel cell operates at an elevated pressure, a constituting a SOFC/gas turbine hybrid system. Oxygen is extracted from the high pressure cathode exit gas using ion transport membrane technology and supplied to the oxy-fuel power system. The entire system generates much more power than the fuel cell only system due to increased fuel cell voltage and power addition from oxy-fuel system. More than one third of the power comes out of the oxy-fuel system. The system efficiency is also higher than that of the fuel cell only system. Recovering most of the generated carbon dioxide is major advantage of the system.

• Journal of Mechanical Science and Technology
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• v.20 no.3
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• pp.391-398
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• 2006

This work involves a method for modeling the flow distribution in the stack of a solid oxide fuel cell. Towards this end, a three dimensional modeling of the flow through a Solid Oxide Fuel Cell (SOFC) stack was carried out using the CFD analysis. This paper examines the efficacy of using cold flow analysis to describe the flow through a SOFC stack. It brings out the relative importance of temperature effect and the mass transfer effect on the SOFC manifold design. Another feature of this study is to utilize statistical tools to ascertain the extent of uniform flow through a stack. The results showed that the cold flow analysis of flow through SOFC might not lead to correct manifold designs. The results of the numerical calculations also indicated that the mass transfer across membrane was essential to correctly describe the cathode flow, while only temperature effects were sufficient to describe the anode flow in a SOFC.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.6
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• pp.759-764
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• 2011

Mixed-conducting oxide powders, $BaCe_{0.9}Y_{0.1}O_{2.95}$ (BCY) and $SrCe_{0.9}Y_{0.1}O_{2.95}$ (SCY) powders have been prepared by a solid-state reaction method. Xray diffraction patterns of the prepared powders showed the sharp peaks of the $BaCe_{0.9}Y_{0.1}O_{2.95}$ and $SrCe_{0.9}Y_{0.1}O_{2.95}$ phases. The oxide powders that were prepared by attrition milling showed rather large particles and severe necking between particles in FE-SEM images as well as residual reactant ($BaCO_3$) and secondary phases ($SrCeO_3$ and $CeO_2$) in XRD patterns. The oxide powders prepared using ball milling showed particles under approximately 500 nm and typical XRD patterns of the $BaCe_{0.9}Y_{0.1}O_{2.95}$ and $SrCe_{0.9}Y_{0.1}O_{2.95}$ phases. Ceramic membranes of the $BaCe_{0.9}Y_{0.1}O_{2.95}$ and $SrCe_{0.9}Y_{0.1}O_{2.95}$ phases were fabricated by the aerosol deposition method using the oxide powders synthesized.

• Journal of the Korean Electrochemical Society
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• v.19 no.3
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• pp.107-113
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• 2016

In this study, an anion-exchange ionomer solution was prepared by grinding poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) in liquid nitrogen for solid alkaline fuel cells (SAFCs). Type of quaternized PPO (QPPO) solutions was controlled by grinding time. The ionomer binder solutions were characterized in terms of dispersity, particle size, and electrochemical properties. As a result, ionomer binder solutions using grinded polymer showed higher dispersion and smaller particle size distribution than that using non-grinded polymer. The highest ionic conductivity and IEC of the membrane recast by using BPPO-G120s were $0.025S\;cm^{-1}$ and $1.26meq\;g^{-1}$, respectively.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.95-105
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• 2009

Fuel cells are applied to the propulsion system of aircraft based on environmental-friendly characteristics with low noise and zero emission of CO2, currently many kinds of UAV and small manned aircraft equipped with fuel cells are being developed. Fuel cells for aircraft typically classified into PEMFC(Proton Exchange Membrane Fuel Cell) type and SOFC(Solid Oxide Fuel Cell) type and the system is developed to adapt missions and operational conditions of aircraft. For UAV, various types of aircraft mostly based on PEM fuel cell technology are investigated for military or commercial uses, and the stability and endurance of system will be improved. For small manned aircraft, many researches are carried out to substitute the propulsion system by fuel cell, also some developments for the higher performance of APU of large commercial aircraft to apply fuel cells are in progress. In the future, a fuel cell aircraft will be expected to improve the reliability and efficiency with higher power density.

• Journal of Electrochemical Science and Technology
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• v.9 no.3
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• pp.212-219
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• 2018

Perovskite type ceramic membranes which exhibit dual ion conduction (proton and oxygen ion conduction) can permeate water and can aid solving operational problems such as temperature gradient and carbon deposition associated with a working solid oxide fuel cell. From this point of view, it is crucial to reveal water transport mechanism and especially the nature of the surface sites that is necessary for water incorporation and evolution. $BaCe_{0.8}Y_{0.2}O_{3-{\alpha}}$ (BCY20) was used as a model proton and oxygen ion conducting membrane in this work. Four different catalytically modified membrane configurations were used for the investigations and water flux was measured as a function of temperature. In addition, CO was introduced to the permeate side in order to test the stability of membrane against water and $CO/CO_2$ and post operation analysis of used membranes were carried out. The results revealed that water incorporation occurs on any exposed electrolyte surface. However, the magnitude of water permeation changes depending on which membrane surface is catalytically modified. The platinum increases the water flux on the feed side whilst it decreases the flux on the permeate side. Water flux measurements suggest that platinum can block water permeation on the permeate side by reducing the access to the lattice oxygen in the surface layer.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1995.03a
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• pp.90-106
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• 1995

The "O"S' BONDING make metallic and non-metalic crystal structures and form localized superconducting orbitals , which induce electrical conduction , semi-conduction, and superconduction. The orbitals are proced by Ampere's law, Faraday's law , Meissner effect, highcritical temperature of thecopper oxide layers. abnomal trans-membrane signal in cancer cell and plastic deformations bytwins and dislocations, In the case of alloying metals, the most deterimentla cases of electrical conduction are those of solid solution and intermetalic compound . The highest case for the hardness are also those of solid solution and intermetallic compound. It explains the contributions of the "O"S' BONDING for conduction bands and plastic deformation by twins and dislocations.ns and dislocations.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.9
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• pp.931-935
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• 2012

In this study, we fabricate and investigate low-temperature solid oxide fuel cells with a ceramic substrate/porous metal/ceramic/porous metal structure. To realize low-temperature operation in solid oxide fuel cells, the membrane should be fabricated to have a thickness of the order of a few hundreds nanometers to minimize IR loss. Yttrium-doped barium zirconate (BYZ), a proton conductor, was used as the electrolyte. We deposited a 350-nm-thick Pt (anode) layer on a porous substrate by sputter deposition. We also deposited a 1-${\mu}m$-thick BYZ layer on the Pt anode using pulsed laser deposition (PLD). Finally, we deposited a 200-nm-thick Pt (cathode) layer on the BYZ electrolyte by sputter deposition. The open circuit voltage (OCV) is 0.806 V, and the maximum power density is 11.9 mW/$cm^2$ at $350^{\circ}C$. Even though a fully dense electrolyte is deposited via PLD, a cross-sectional transmission electron microscopy (TEM) image reveals many voids and defects.