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        검색결과 3

        1.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A drop weight impact test was conducted in this study to analyze the mechanical and thermal properties caused by the changes in the ratio of carbon fiber reinforced plastic (CFRP) to ethylene vinyl acetate (EVA) laminations. The ratios of CFRP to EVA were changed from 10:0 (pure CFRP) to 9:1, 8:2, 6:4, and 5:5 by manufacturing five different types of samples, and at the same time, the mechanical/thermal properties were analyzed with thermo-graphic images. As the ratio of the CFRP lamination was increased, in which the energy absorbance is dispersed by the fibers, it was more likely for the brittle failure mode to occur. In the cases of Type 3 through Type 5, in which the role of the EVA sheet is more prominent because it absorbs the impact energy rather than dispersing it, a clear form of puncture failure mode was observed. Based on the above results, it was found that all the observation values decreased as the EVA lamination increased compared with the CFRP lamination. The EVA lamination was thus found to have a very important role in reducing the impact. However, the strain and temperature were inversely propositional.
        4,000원
        2.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Rapid industrial development in recent times has increased the demand for light-weight materials with high strength and structural integrity. In this context, carbon fiber-reinforced plastic (CFRP) composite materials are being extensively used. However, laminated CFRPs develop faults during impact because CFRPs are composed of mixed carbon fiber and epoxy. Moreover, their fracturing behavior is very complicated and difficult to interpret. In this paper, the effect of the direction of lamination in CFRP on the absorbed impact energy and impact strength were evaluated, including symmetric ply (0°/0°, –15°/+15°, –30°/+30°, –45°/+45°, and –90°/+90°) and asymmetric ply (0°/15°, 0°/30°, 0°/45°, and 0°/90°), through drop-weight impact tests. Further, the thermal properties of the specimens were measured using an infrared camera. Correlations between the absorbed impact energy, impact strength, and thermal properties as determined by the drop-weight impact tests were analyzed. These analyses revealed that the absorbed impact energy of the specimens with asymmetric laminated angles was greater than that of the specimens with symmetric laminated angles. In addition, the asymmetry ply absorbed more impact energy than the symmetric ply. Finally, the absorbed impact energy was inversely proportional to the thermal characteristics of the specimens.
        4,000원
        3.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, activated carbons nanofibers (ACNFs) were prepared from polyacrylonitrile-based nanofibers by physical (H2O and CO2) and chemical (KOH) activation. The surface and structural characteristics of the porous carbon were observed by scanning electron microscopy and X-ray diffraction, respectively. Pore characteristics were investigated by N2/77K adsorption isotherms. The specific surface area of the physically ACNFs was increased up to 2400m2/g and the ACNFs were found to be mainly composed of micropore structures. Chemical activation using KOH produced ACNFs with high specific surface area (up to 2500m2/g), and the micropores were mainly found in the ACNFs. The physically and chemically ACNFs showed both mainly type I from the International Union of Pure and Applied Chemistry classification.
        4,000원