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        검색결과 10

        1.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An environmentally friendly and low-cost chitosan-containing polysaccharide (CP) composite ZIF-8/CP was designed and prepared based on the difficulty of separating the traditional adsorbent from the water phase. ZIF-8/CP was synthesized through in-situ growth approach. The physical, chemical and structure properties of ZIF-8/CP were determined through a series of characterization methods, including SEM, FT-IR and PXRD. The effects of touch time, pH, temperature, and coexisting ions on adsorption were assessed. In addition, kinetics, isotherms of adsorption and thermodynamics were examined. The data of isotherms for adsorption indicated that the adsorption of ZIF-8/CP on MG was similar to the Langmuir model, with a maximum adsorption capacity of 1428.57 mg/g. Moreover, the kinetic parameters were consistent with the pseudo- 2nd-order equation. Thermodynamic studies (ΔG < 0, ΔH > 0) demonstrated a heat-absorbing and spontaneous adsorption process. Our study reveals that ZIF-8/CP has good adsorption properties and environmental properties.
        4,200원
        5.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, graphene-coated Al powders prepared by in situ reduction method were directly used for cold spraying, obtaining a graphene-reinforced Al matrix composite coating with more compact structure and better performance. Cross-sectional analysis revealed that compared with the pure Al powders, the graphene-coated Al powders were more severely deformed, and the resulting coating was denser and its porosity was reduced by over 80%. The hardness of the graphene-coated Al coating was increased by 40%, and its brine immersion time was prolonged by nearly three times. However, the graphene increases the pitting sensitivity of the Al coating; so, the enhanced corrosion resistance of the graphene-coated Al coating is mainly attributed to the improvement of its structure densification.
        3,000원
        6.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In aluminum electrolysis, sodium penetration into carbon cathodes is considered as the main cause of cell failure and efficiency loss, but the detailed mechanism is still not definitely clear. Since the macroscopic properties of material depend on the microscopic structures, a large-scale atomistic model of anthracite cathodes was constructed to represent several important structural characteristics. Combined with Monte Carlo and molecular dynamics simulations, the adsorption and diffusion behaviors of sodium were investigated, respectively. The results suggest that sodium adsorption mainly occurs in the larger micro-pores with the range of 10–19 Å, while it accords well with to type-I Langmuir adsorption model. The sodium is found to be preferentially adsorbed in arch-like structures with 5- or 7-membered rings or around heteroatom, especially oxygen. Moreover, the movements of sodium through carbon matrix mainly depend on the continuous diffusive motion while most sodium particles tend to be trapped in voids with small mobility. The calculated transport diffusion coefficient is equal to 6.132 × 10− 10 m2/ s, which is in outstanding agreement with experimental results. This fundamental research would contribute to the understanding of sodium penetration mechanism and the optimization of cathode industry in the future.
        4,200원
        7.
        2020.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The US has huge interests in Hong Kong. In 1992, a few years before China resumed its sovereignty over Hong Kong in 1997, the US adopted the U.S.-Hong Kong Policy Act of 1992. The keynote of the Act is to enhance the cooperation with and maintain the treatment to Hong Kong. This tune has changed in the Hong Kong Human Rights and Democracy Act of 2019, which is obviously the response of the US to widespread protests in Hong Kong arising from the Extradition Bill proposed by the Government of Hong Kong SAR. The new law includes several negative elements. It marks a change in the US policy towards Hong Kong and furthermore represents a change in the US policy towards China. The new law should not merely be understood as the US’s support for democracy and human rights in Hong Kong. Instead, it should be considered as a major leverage which the US may maneuver to engage a rising China.
        4,600원