• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.606-609
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• 2000

We describe the preparation of a manganese oxide polymorph in which the solid-pore architecture of the material is controllably varied. All MnO$_2$ gels derived from a KMnO$\_$4/-based sol-gel synthesis. The mesoporous structure of the initial gel is maintained by removingore fluid under conditions where the capillary forces that result fro extraction are either low or no existent. are either low or noexistent. Controlling both the pore and solid architecture on the nanoscale offers a strategy for the design of supercapacitor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.60-61
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• 2007

In this paper, the p-channel poly Si thin-film transistors (Poly-Si TFT's) using formed by solid phase crystallization (SPC) on glass substrate were fabricated. And we propose an ONO(Oxide-Nitride-Oxide) multilayer as the gate insulator for poly-Si TFT's to indicate non-volatile memory (NVM) effect. Poly-Si TFT is investigated by measuring the electrical properties of poly-Si films, such as I-V characteristics, on/off current ratio. NVM characteristics is showed by measuring the threshold voltage change of TFT through I-V characteristics.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.310.2-310.2
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• 2013

For enhancement of dye-sensitized solar cell performance, TiO2 blocking layer has been used to prevent recombination between electron and hole at the conducting oxide and electrolyte interface. In solid state dye-sensitized solar cells, it is necessary to fabricate pin-hole free TiO2 blocking layer. In this work, we deposited the TiO2 blocking layer on conducting oxide by atomic layer deposition and compared the efficiency. To compare the efficiency, we fabricate solid state dye-sensitized solar cell with using CuSCN as hole transport material. We see the efficiency improve with 40nm TiO2 blocking layer and the TiO2 blocking layer morphology was characterized by SEM. Also, we used this blocking layer in TiO2/Sb2S3/ CuSCN solar cell.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.741-749
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• 1994

The planar solid oxide fuel cell(SOFC) contains several ceramic materials depending on its structure and has rdfractory metal parts for manifolds, shrouds and current leads. Among ceramic materials for planar SOFC, joining of lanthanum chromite separator and yttria stabilized zirconia(YSZ) electoyte in planar SOFC stack to give strong gas tight seals is necessary for satisfactory operation and high performance. Nevertheless, for planar SOFC/sub s/, how to seal the cell stack and gas manifold remains as one of the unsolved problems. Therefore, in this study. we investigated the joining of sintered lanthanum chromite and YSZ pellets using unsintered lanthanum chromite green films as sealent. Scanning electron microscopy(SEM) and energy dispersive X-ray analysis(EDX) revealed that Ca in the sealing material diffused and dissolved into YSZ and sintered lanthanum chromite, and unsintered lanthanum chromite green films reacted with YSZ to from a new phase at the interface. Also, the densification of unsintered lanthanum chromite green films was inpeded by the Ca migration.

• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.885-890
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• 2006

This study presents analysis results for the hybrid system combining solid oxide fuel cell and gas turbine. Two different system layouts(an ambient pressure system and pressurized system) are considered and their design performance are comparatively investigated taking into account critical design factor, the most critical parameter such as turbine inlet temperature, gas turbine pressure ratio, temperature difference at the fuel cell and fuel cell operating temperature are considered as design constraints. Performance variations according to system layout and design parameters are examined in energetic view point.

• Journal of the Korean Society of Propulsion Engineers
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• v.26 no.6
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• pp.28-33
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• 2022

In this study, the curing characteristics of commonly used Hydroxyl terminated polybutadiene(HTPB)-based solid propellant according to the curing temperature and Equivalent ratio change were investigated. In addition, the effect of curing reaction according to their ratio and content in the Triphenyl bismuth(TPB), Maleic anhydride(MA) and Magnesium oxide(MgO) catalyst systems was confirmed. Finally, moisture was added for each propellant mixing process to check the effect of moisture on propellant curing.

• Journal of Electrochemical Science and Technology
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• v.14 no.2
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• pp.145-151
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• 2023

Planer-type electrolyte substrates are often utilized for stack manufacturing of electrolyte-supported solid oxide fuel cells (ES-SOFCs) to fulfill necessary requirements such as a high mechanical strength and redox stability. This work did an electrochemical analysis of ES-SOFC with different NiO-YSZ anode thicknesses to find the optimal value for the high performance of the fuel cell. The cell resistivities were constant at anode thickness between 25-58 ㎛, but a thick anode (74 ㎛) caused a high electrode resistivity leading to a dramatic reduction in cell performance. A stability test was performed for 50 hours at 700℃, and the results showed a degradation rate of 0.3% per 1000 h by extrapolated fitting.

• Transactions of the Korean hydrogen and new energy society
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• v.35 no.4
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• pp.437-450
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• 2024

Sustainable shipping depends on eco-friendly energy solutions. This paper reviews methods for predicting marine fuel cell performance, including empirical approaches, physical modeling, data-driven techniques, and hybrid methods. Accurate prediction models tailored to the marine environment's unique conditions are crucial for operational efficiency. By evaluating the strengths and weaknesses of each method, this study provides a comprehensive analysis of effective strategies for forecasting polymer electrolyte membrane fuel cell and solid oxide fuel cell performance in marine applications. These insights contribute to the advancement of eco-friendly shipping technologies and enhance fuel cell performance in challenging marine environments.

• Journal of Powder Materials
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• v.7 no.4
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• pp.218-227
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• 2000

It is well known that the Cu-Cr alloys are very difficult to be made by conventional sintering methods. This difficulty originates both from limited solubility of Cr in the Cu matrix and from limited sintering temperature due to high vapor pressures of Cr and Cu components at the high temperature. Densification of Cu-50%Cr Powder compacts by conventional Powder metallurgy Process has been studied. Three kinds of sintering methods were tested in order to obtain high-density sintered compacts. Completely densified Cu-Cr compacts could be obtained neither by solid state sintering method nor by liquid phase sintering method. Both low degree of shrinkage and evolution of large pores in the Cu matrix during the solid state sintering are attributed to the anchoring effect of large Cr particles, which inhibits homogeneous densification of Cu matrix and induces pore generation in the Cu matrix. In addition, the effect of undiffusible gas coming from the reduction of Cu-oxide and Cr-oxide was observed during liquid phase sintering. A two-step sintering method, solid state sintering followed by liquid phase sintering, was proved to have beneficial effect on the fabrication of high-dendsity Cu-Cr sintered compacts. The sintered compacts have properties similar to those of commercial products.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.9-17
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• 1996

Solid oxide electrolytes of 8mol% YSZ($Y_2O_3$ stabilized zirconia) were prepared at various sintering conditions and their ionic conductivities were measured. The highest ionic conductivity of $10^{-1}S.cm^{-1}$ was obtained when the sintering temperature was 1400oC and the sintering time was 10hr. Also the cathode material, $La_{1-x}Sr_xMnO_3$ was prepared by solid state reaction method and the overpotential, electrical conductivity, and charge transfer resistance between cathode material and YSZ electrolyte were studied. It was found that the optimum doping content of Sr for La was 50mo1%.