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The Influence of the Commercial Flame Retardant to the Physical and Chemical Properties of Dancheong Pigments (시판용 방염제 도포에 의한 단청안료의 물리화학적 변화 연구)

  • Lee, Han Hyoung;Kim, Jin Gyu;Lee, Hwa Soo;Lee, Ha Rim;Chung, Yong Jae;Kim, Do Rae;Han, Gyu Seong
    • Journal of Conservation Science
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    • v.32 no.2
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    • pp.249-259
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    • 2016
  • Effect of the flame retardants on Dancheong is studied in the present work. Two kinds of flame retardants were applied on Dancheong specimens and compared with control groups on which distilled water was applied instead of the flame retardants. The flame retardants enhanced the hygroscopic property of the surface of Dancheong. Furthermore, the added flame retardants reacted with oyster shell white($CaCO_3$) and lead red($Pb_3O_4$), producing new chemical compounds like Calcium phosphate tribasic and Lead Phosphates which make the painted layer of Dancheong dissolving and whitening over certain period of time. When applied in excessive amount and exposed in repetitive wet and dry condition, especially, they aggravate the surface problems significantly. These results will provide a good reference on the study of the discoloring/whitening effect of Dancheong layers at many traditional wooden building in Korea.

Fabrication and Characterization of the Carbon Fiber Composite Sheets (탄소섬유를 이용한 열가소성 복합재료 시트 제조 및 특성)

  • Lee, Yun-Seon;Song, Seung-A;Kim, Wan Jin;Kim, Seong-Su;Jung, Yong-Sik
    • Composites Research
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    • v.28 no.4
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    • pp.168-175
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    • 2015
  • Recently, the applications of carbon fiber reinforced plastics (CFRPs) have become broader than ever when it comes to such industries as automotive, ships, aerospace and military because of their lightweight-ness and high mechanical properties. Thermosetting plastics like epoxy are frequently used as the binding matrix in CFRPs due to their high hardness, wetting characteristics and low viscosity. However, they cannot melted and remolded. For this reason, thermosetting plastic wastes have caused serious environmental problems with the production of fiber reinforced plastics. Thus, many studies have focused on the carbon fiber reinforced thermoplastics (CFRTPs) and recycling carbon fiber. In this study, recycled carbon fiber (RCF) was prepared from CFRPs using a pyrolysis method, which was employed to separate resin and carbon fiber. The degree of decomposition for epoxy resin was confirmed from thermal gravimetric analysis (TGA) and scanning electron microscope (SEM). The RCF was cut and ground to prepare a carbon fiber composite sheet (CFCS). CFCS was manufactured by applying recycled carbon fibers and various thermoplastic fibers. Various characterizations were performed, including morphological analyses of surface and cross-section, mechanical properties, and crystallization enthalpy of CFCS at different cooling conditions.

Effects of Flux Activator on Wettability and Slump of Sn-Ag-Cu Solder Paste (플럭스 활성제 종류에 따른 Sn-Ag-Cu 솔더 페이스트의 젖음성 및 슬럼프 특성 평가)

  • Kwon, Soonyong;Seo, Wonil;Ko, Yong-Ho;Lee, Hoo-Jeong;Yoo, Sehoon
    • Journal of the Microelectronics and Packaging Society
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    • v.25 no.4
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    • pp.123-128
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    • 2018
  • Effect of activators in flux on the printability and wettability of a solder paste was evaluated in this study. The activators in this study were dicarboxylic acids, which were oxalic acid (n = 0), malonic acid (n = 1), succinic acid (n = 2), glutaric acid (n = 3), adipic acid (n = 4), and pimelic acid (n = 5). When the solder pastes were observed with a SMT scope, solder with glutaric acid showed clean and shiny surface when it was melted. Slump ratio of the solder pastes was low when the carbon numbers of the dicarboxylic acid were 1-3. Spreadability was high when the carbon number was over 2. Zero cross time of wetting balance test was under 1 sec when the carbon number was over 3. When activator was oxalic acid or malonic acid, zero cross time was over 1 sec and maximum wetting force was low. Fluxes with the oxalic acid and malonic acid showed decomposition at the temperature close to melting point. Among the dicarboxylic acids, glutaric acid provided excellent slump, spreadability, and wettability.