• Elastomers and Composites
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• 제52권3호
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• pp.211-215
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• 2017

Thermally expandable microspheres were used as post-treatment initiators of potassium persulfate, sodium bisulfite, and sodium sulfide in order to improve the foaming ability and whiteness when foaming a mixture of thermally expandable microsphers and poly(vinyl chloride). Potassium persulfate showed no significant influence on the foaming behavior, foam expansion, whiteness, and yellowing, whereas in the case of using sodium bisulfite. In particular, sodium bisulfite demonstrated the best efficiency with 2 wt% treatment. The thermally expandable microspheres prepared herein can provide excellent foamability and whiteness, and are expected to be applicable in various fields such as general coating and wallpaper.

• 신재생에너지
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• 제4권1호
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• pp.31-36
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• 2008

Stainless steels have been widely considered as metallic bipolar plates, due to their passive surface film, which is good for corrosion resistance. However, the high resistivity of the passive film increases interfacial contact resistance between the bipolar plates and the electrodes. Stainless steels thermal spray coated with a mixture of tungsten carbide and stainless steel powders showed that the coated layer safely combined with the matrix but they suffered many internal defects including voids and cracks. Many cracks were formed in the coated layer and the interface of the matrix and the coated layer during the rolling process. The coated and rolled stainless steels showed lower interfacial contact resistance and corrosion resistance than bare stainless steel because of low resistivity of tungsten carbide and numerous defects, which caused crevice corrosion, in the coated layer.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.964-967
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• 2002

The effectiveness of silicon nitride SiNx surface passivation is investigated and quantified. This study adopted single-layer antireflection (SLAR) coating of SiNx for efficiency improvement of solar cell. The silicon nitride films were deposited by means of plasma enhanced chemical vapor deposition (PECVD) in planar coil reactor. The process gases used were pure ammonia and a mixture of silane and helium. The thickness and the refractive index on the films were measured by ellipsometry and chemical bonds were determined by using an FT-IR equipment. This films obtained were analyzed in term of hydrogen content, refractive index for gas flow ratio $(NH_3/SiH_4)$, and efficiency of solar cell. The polycrystalline silicon solar cells passivated by silicon nitride shows efficiency above 12.8%.

• Computers and Concrete
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• 제19권5호
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• pp.451-455
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• 2017

Technological advancements in the field of building materials are achieved day by day. In this study, a new lightweight concrete aggregate is produced by mixing certain rates of colemanite (0%, 7.5%, 12.5%, 17.5%), cement and coating the surface of pumice aggregate with this mixture. Thin aggregate sections are analyzed with specific gravity, unit weight, water absorption, impact, and crushing experiments. In this way, the production of cement and cement+colemanite coated lightweight concrete aggregates is investigated and an opinion on the likely behavior of these concrete types is provided.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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• pp.288-291
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• 2001

It is very important to select suspension solution for forming electrophoretic deposited YBCO thick mm, because it is heavily affected to its superconducting properties. In this paper, high-temperature superconductor films of $YBa_{2}Cu_{3}O_{7-x}$ were fabricated by electrophoretic deposition (EPD) from alcohol-based suspension such as iso-propanol, iso-butanol, and their mixture. For the formation of YBCO dense and adherent coating on a silver wire by EPD, 1 % PEG(1000) 2 ml, as a additive for making their surface crack-free, was used for electrophoresis. As a results, the cracks were considerably decreased and the superconducting critical current density $(J_e)$ without/with PEG was $1200A/cm^2$ and $2020A/cm^2$, which films deposited in mix iso-propanol and iso-butanol suspension.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.1-5
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• 2008

Stainless steels have been widely considered as metallic separators, due to their passive surface film, which is good for corrosion resistance. However, the high resistivity of the passive film increases interfacial contact resistance between the separators and electrodes. Stainless steels thermal spray coated with a mixture of tungsten carbide and stainless steel powders showed that the coated layer safely combined with the matrix but they suffered many internal defects including voids and cracks. Many cracks were formed in the coated layer and the interface of the matrix and the coated layer during the rolling process. The coated and rolled stainless steels showed lower interfacial contact resistance and corrosion resistance than bare stainless steel because of low resistivity of tungsten carbide and numerous defects, which caused crevice corrosion, in the coated layer.

• 한국분말재료학회지
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• 제8권3호
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• pp.174-178
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• 2001

The microstructure and mechanical properties of $Si_3N_4/BN $nanocomposites synthesized by chemical processing were investigated. The nanocomposites containing 15 vol% hexagonal BN (h-BN) were fabricated by hot-pressing $\alpha-Si_3N_4$powders covered with turbostratic BN (t-BN). The t-BN coating on $\alpha-Si_3N_4$particles was prepared by heating $\alpha-Si_3N_4$ particles covered with a mixture of boric acid and urea in hydrogen gas. TEM observations of this nanocomposite revealed that nano-sized h-BN particles were homogeneously dispersed within $Si_3N_4$grains as well as at grain boundaries. The strength and thermal shock resistance were significantly improved in comparison with the $Si_3N_4/BN$ microcomposites.

• 한국염색가공학회지
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• 제19권2호
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• pp.24-31
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• 2007

This paper addresses factors of line image quality on grain leather printed via inkjet printer. Lines were printed onto coated leather media, and line width, edge blurriness, and edge raggedness were evaluated for line image quality. Various factors influenced to wetting and capillary wicking were studied and found out that wicking through capillary between fibers causes significant feathering on leather surface similar with pulp capillary in copy Paper. Polyurethane and acrylic resin coating resulted good image qualify by reducing capillary wicking. The mixture of polyurethane and acrylic resin applied on grain leather satisfied with both image quality and surface hand. $AllWrite^{TM}$ ink brought best results of image quality, comparing with $VeraPrint^{TM}$ ink and $JetWrite^{TM}$ ink.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권4호
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• pp.136-139
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• 2003

The positive column of a discharge tube filled with a mixture of mercury-xenon has a tendency to become contracted at room temperature. However, once the tube temperature is raised over 50 [$^{\circ}C$], the positive column changes from a contracted state to a diffused state. The xenon emission is stronger in the contracted positive column than in the diffused column. Alternatively, the mercury emission is more intense in the diffused positive column, and the luminance of the phosphor coating on the inner surface of the tube is higher than that in the contracted positive column. Moreover, higher luminance can be obtained by increasing the xenon pressure.

• Elastomers and Composites
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• 제26권4호
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• pp.296-303
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• 1991

Surface of crystalline silica was sequentially reacted with silane(A 187), liquid $rubber(CTBN{\times}8)$, and vinyl monomer(GMA) in existence of TEA(triethylamine) or BPO(benzoyl peroxide). It was mixed with epoxy resin at a ratio $0{\times}60%$ (vol. % ) of total component. For mixtures, viscous properties were investigated experimentally. 1) Coating ratio depended on pH of mixture and quantity of catalyst. 2) Treated silica represented lower viscosity than untreated. 3) Thixotropic index represented best at silica_content $15{\sim}23%$ and showed more large deviation over $120^{\circ}C$. 4) Relative viscosity followed kernel's at $0{\times}10%$ of silica content and get out of Mooney's at more than 15%.