• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.90.1-90.1
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• 2010

The design and fabrication of a metallic bipolar plate-gasket assembly for polymer electrolyte fuel cells (PEMFCs) is defined. This bipolar plate-gasket assembly was prepared by inserting a previously prepared bipolar plate in the specially designed gasket mold. For this aim, a proprietary fluoro-silicone based rubber was injected directly into the bipolar plate borders. Gaskets obtained like this showed the chemically / physically stable and the good sealibilty in typically operating PEM fuel cell conditions. And also, this bipolar plate-gasket assembly shows lots of advantages with respect to traditional PEMFCs stack assembling systems: useful application to automative stacking due to easy handling, reduced fabrication time, possibility of quality control and failed elements substitution. This bipolar plate-gasket assembly was evaluated in the short fuel cell stack and met the leakage requirement for normal operation both in short-term and in long-term operation. Especially, it was confirmed that this gasket could be applied successfully even in the high pressure FEM fuel cell systems(over 2.0 bar in absolute pressure).

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.1089-1094
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• 1993

A pilot system for flexible automatic assembly has been built at ASRI in Seoul National University. The system is designed for being capable of assembling different variants and products. The system consists of three industrial robots, four free-flow conveyors, automatic tool changers, RCC and fixtures. This paper describes the concept and the technical solutions of the developed flexible assembly cell. Results of performance evaluation using colored petri net are also presented and discuss.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.10
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• pp.1579-1589
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• 2020

Objective: This study was conducted to investigate the roles of LIM kinases (LIMK1 and LIMK2) during porcine early embryo development. We checked the mRNA expression patterns and localization of LIMK1/2 to evaluate their characterization. We further explored the function of LIMK1/2 in developmental competence and their relationship between actin assembly and cell junction integrity, specifically during the first cleavage and compaction. Methods: Pig ovaries were transferred from a local slaughterhouse within 1 h and cumulus oocyte complexes (COCs) were collected. COCs were matured in in vitro maturation medium in a CO2 incubator. Metaphase II oocytes were activated using an Electro Cell Manipulator 2001 and microinjected to insert LIMK1/2 dsRNA into the cytoplasm. To confirm the roles of LIMK1/2 during compaction and subsequent blastocyst formation, we employed a LIMK inhibitor (LIMKi3). Results: LIMK1/2 was localized in cytoplasm in embryos and co-localized with actin in cell-to-cell boundaries after the morula stage. LIMK1/2 knockdown using LIMK1/2 dsRNA significantly decreased the cleavage rate, compared to the control group. Protein levels of E-cadherin and β-catenin, present in adherens junctions, were reduced at the cell-to-cell boundaries in the LIMK1/2 knockdown embryos. Embryos treated with LIMKi3 at the morula stage failed to undergo compaction and could not develop into blastocysts. Actin intensity at the cortical region was considerably reduced in LIMKi3-treated embryos. LIMKi3-induced decrease in cortical actin levels was attributed to the disruption of adherens junction and tight junction assembly. Phosphorylation of cofilin was also reduced in LIMKi3-treated embryos. Conclusion: The above results suggest that LIMK1/2 is crucial for cleavage and compaction through regulation of actin organization and cell junction assembly.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.19 no.40
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• pp.253-261
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• 1996

In optimizing the layout design of a multi-product assembly environment, tile analysis of the material flow is a vital ingredient. In flexible assembly systems, assembly time is usually very short thus the transfer time is relatively more important Therefore operations sequence must be so determined, that have no backtracking operations as possible as, It is important to form cells, so that they have no intercell movement in curring much processing delay, and to arrange machines as possible as densly. This study presents a independent cell formation method considering operation sequences and machine capacity in flexible assembly systems.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.153-158
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• 2000

This paper addresses an intelligent robot control system using an off-line programming to teach a precise assembly task of electronic components in a flexible way. The investigated task consists of three job: heat caulking test, soldering on a circuit board, and checking of soldering defects on the back cover of a camera. This study investigates the remodelling of the most complicated cell in terms of the accuracy and fault rate among the twelve cells in a camera back-cover assembly line. We have attempted to enhance back-cover assembly line. We have attempted to enhance soldering quality, to add task flexibility, to reduce failure rate, and to increase product reliability. This study modifies the cell structure, and improves the soldering condition. The developed all system implements the real-time control of assembly with vision data, and realized an easier task teaching on off-line programming.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.50
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• pp.209-219
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• 1999

This paper presents an efficient operational technique of material feeding process, trainning for multi-operations, machine conditions, and role of foreman and material-supplying man, for constructing the flexible assembly cells in the domestic electronic industries. And an practical method for computing the number of economical cells is also presented by the cost-effective model that compares the additional assembly machine requirement with the four reductive effects including WIP/finished goods inventory, the troubles in the assembly line, the opportunity loss for small order quantity, and amounts of production management due to the introduction of cell line. An case study is introduced in for a domestic electronic assembly line at the end.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.49-54
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• 1992

A flexible robotic assembly cell is modeled using Petri net. A simulator is developed and used to predict the optimal status of the system. The assembly cell of flexible manufacturing system(FMS) pilot plant of Automation and Systems Research Institute(ASRI) in Seoul National University is modeled. The system consists of 3 robots, 4 conveyors, automatic guided vehicle(AGV) and auto-stacker. The simulator is programmed in Turbo C on IBM PC, supporting a simple graphic simulation with pull-down menu. The flexibility of the assembly cell in the FMS plant is guaranteed, since it is possible to predict the optimal status of the system using this simulator.

• Macromolecular Research
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• v.16 no.6
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• pp.524-531
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• 2008

The mitigation or elimination of methanol crossover for perfluorosulfonic acid fuel cell membranes has been investigated extensively for direct methanol fuel cell applications with the aim of increasing the electrochemical performance and enhancing the utilization rate of methanol. Self-assembly modifications by applying an oppositely charged polyelectrolyte to Nafion membranes were attempted in order to block or reduce methanol crossover while maintaining the other advantageous properties of Nafion membranes. It was reported that anionic polyallylamine hydrochloride (PAH) was the most efficient polyelectrolyte in reducing methanol crossover, and considerable cell performance was obtained even at a methanol feed concentration of 10 M.

• 한국전기화학회:학술대회논문집
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• 2002.10a
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• pp.8-8
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• 2002

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.6
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• pp.547-553
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• 2015

For commercialization of fuel cell electric vehicles, one of the key objectives is to reduce cost of full stack assembly. Regarding Membrane Electrode Assembly, the major issue is to improve fuel cell activation process in the initial Hydrogen Oxidation Reaction and Oxygen Reduction Reaction. In this research, the VD (Vacuum Drying) process has been developed for improvement of activation process. The VD condition is developed by controlling the temperature and degree of vacuum to remove the remaining solvent of electrode. Consequently, the electrode applied to VD process showed the low characteristics such as 3.5% of remaining solvent content and the improved efficiency such as 15% of activation process speed.