• Transactions of the Korean hydrogen and new energy society
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• v.22 no.5
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• pp.585-591
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• 2011

This study has focused on the development of high performance membrane-electrode assemblies (MEAs) fabricated by decal method for proton exchange membrane fuel cell (PEMFC). To study the effect of ionomer contents on performance, we fabricated MEAs with several electrodes which were prepared by varying the quantity of ionomer from 20 wt.% to 45 wt.% in catalyst layer. The MEA performance was obtained through single cell test. The MEA prepared from electrode with 25wt.% of ionomer showed the best performance. We evaluated the surface area and pore volume of electrode with BET. We found that the surface area and pore volume in electrode decreased rapidly at the electrode with 40wt.% of ionomer in catalyst layer. MEA was fabricated by roll laminator machine and the roll laminating conditions for the preparation of MEA, such as laminating press, temperature and speed, were optimized. The MEA performance is not affected by laminating temperature and speed, but roll laminating press have a great effect on MEA performance.

• Korean Journal of Clinical Laboratory Science
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• v.37 no.1
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• pp.47-55
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• 2005

These studies were done to know decalcification methods to reduce the time of decalcification for quick bone tissue diagnosis. When bone tissue was decalcified with 10 % formic acid at room temperature, decalcification and hematoxylin & eosin (H&E) stains were complete and satisfactory after 12 hours, but some of the tissue sections fell off during staining. In this way, decalcification, H&E stains were complete and satisfactory after 24 hours, 36 hours and 48 hours, tissue sections didn't fall off during staining. When bone tissue was decalcified with 10 % formic acid in a $60^{\circ}C$ paraffin oven, decalcification and H&E stains were complete and satisfactory after 6 hours, but some tissue sections fell off during staining. In this way, decalcification and tissue sections were complete, with no falling off during staining after 8 hours, 10 hours, 12 hours, 14 hours, 24 hours, or H&E stains were satisfactory from 8 hours to 12 hours, but H&E stains appeared to reddish nucleus after 14 hours and 24 hours. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at DECAL machine frequencies of 15 Hz and 45 Hz, and for 6 hours, 12 hours and 24 hours at a DECAL machine frequency of 90 Hz. Decalcification and H&E stains were complete and satisfactory after 6 hours at the 15 Hz and 45 Hz DECAL settings. Some of the tissue sections fell off during staining at the 15 Hz DECAL machine setting. At the 90 Hz setting, decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 4 hours. In this way, decalcification, H&E stains, and tissue section were complete and satisfactory with no falling off during staining after 12 hours, 24 hours at all machine settings. Bone tissue was decalcified with 10 % formic acid for 6 hours, 12 hours and 24 hours at $37^{\circ}C$ 3 hours, 6 hours and 12 hours at $45^{\circ}C$ and 1 hours, 5 hours and 10 hours at $60^{\circ}C$ with the RHS-1 machine setting at 60Hz. At the temperatures of $37^{\circ}C$, $45^{\circ}C$, and $60^{\circ}C$ decalcification, H&E stains, and tissue sections were complete and satisfactory, with no falling off during staining except for after 6 hours at $37^{\circ}C$. 3 hours, 1 hours, or decalcification, H&E stains, and tissue sections were complete and satisfactory with no falling off during staining after 12 hours and 24 hours at $37^{\circ}C$, 6 hours and 12 hours at $45^{\circ}C$, and 5 hours at $60^{\circ}C$. But H&E stains appeared to reddish nucleus after 10 hours at $60^{\circ}C$. From the above reults, the authors were able to deduce that decalcification is accelerated by heat and frequency. We therefore think that it is necessary for machines which are similar to the RHS-1 machine to be maintained at the temperature evenly with agitation effect for quick decalcification.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.110-112
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• 2006

Membrane electrode assembly (MEA) for polymer electrolyte fuel cell (PEFC) are commonly prepared in the research laboratory by spraying, screen-printing and brushing catalyst slurry onto membrane or other support material like carbon paper or polyimide film in a batch style. These hand applications of the catalyst slurry are painstaking process with respect to precision of catalyst loading and reproducibility. It has been generally mentioned that the adoption of continuous process is very helpful to develop the reliable product. In the present work, we report the results of using continuous type coater with doctor-blade to coat catalyst slurry for preparing the MEA catalyst layers In a faster and highly reproducible fashion. We show that while expectedly faster than batch style, the machine coater requires the use of slurry of appropriate composition and a properly selected transfer decal material in order to achieve superior MEA plat lnw loading reproducibility. To make highly viscous catalyst slurry that is imperative for using coater, we use 40wt.% Nafion solution and minimize the content of organic solvent. And the choice of proper high surface area catalyst is important in the viewpoint of making well-dispersed slurry. After catalyst coating onto the support material, we transferred the catalyst layer to both sides of Nafion membrane by hot-pressing In this case, the degree of transfer was Influenced by hot-pressing condition including temperature, pressure, and time. To compare the transferring ability, we compared so many films and detaching papers. And among the support, polyethylene terephthalate(PET) film shows the prominent result.