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        검색결과 403

        1.
        2025.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Incorporating nanotechnology into cement composites significantly improves mechanical properties such as strength, toughness, and durability. Graphene, with high tensile strength and large surface area, shows great promise as a nanofiller, but its hydrophobicity complicates its dispersion in cement matrices. This study used a graphene-cellulose nanofiber (G@ CNF) hybrid filler to ensure a highly uniform dispersion within the cement microstructure. The hybrid filler acts as a bridge and efficiently fills voids within the matrix. The planar structure of graphene also provides nucleation sites for hydrated products, leading to a denser microstructure. The cement composite containing 0.01 wt.% graphene exhibited a compressive strength of 72.7 MPa, representing a 47.5% improvement over the plain cement. Furthermore, the resulting cement demonstrated enhanced water resistance compared to graphene oxide-reinforced-cement. This approach offers a cost-effective and sustainable way of producing high-strength, durable cement composite.
        4,600원
        5.
        2025.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Covalent organic framework (COF) membranes have emerged as promising candidates for hydrogen purification due to their tunable pore sizes and robust structures. However, achieving high selectivity and permeability simultaneously remains a challenge due to the inherent pore size distribution of COF materials. In this study, we fabricated two distinct COF membranes, TpPa-1 and TpTGCl, with pore sizes of 1.8 nm and 0.39 nm, respectively, using tailored synthesis methods. The TpTGCl membrane, synthesized via room temperature interfacial polymerization and vacuum-assisted filtration, exhibits an ultrathin nanosheet structure with an interlayer π–π stacking distance of 0.33 nm. This unique architecture, combined with its affinity for CO2 adsorption, enables exceptional hydrogen separation performance, achieving a H2/ CO2 selectivity of 52.5 and a H2 permeability of 3.49 × 10– 7 mol m− 2 s− 1 Pa− 1. Molecular dynamics simulations confirmed the steric hindrance effect as the primary mechanism for the selective permeation of hydrogen. The TpTGCl membrane effectively sieves larger gas molecules ( CO2, N2, CH4, etc.) without the need for material modification or excessive membrane thickness. This study demonstrates the potential of COF membranes with tailored pore sizes for high-performance hydrogen purification and offers valuable insights for the development of advanced separation technologies.
        4,300원
        6.
        2025.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        CNT/epoxy composite film (CECF) was prepared and used to fabricate the interlayer stiffened and reinforced photothermal synergistic curing glass fiber-reinforced polymer (GFRP) composites, and the influence of the photothermal effects of CECF on compressive strength and failure mechanism of the composite was investigated. Compared to GFRP composite, the uniform and wide temperature distribution in the in-plane and thickness direction was exhibited due to the heat from the lattice vibrations induced by photothermal conversions of CECF, thereby facilitating the decomposition of the thermal initiator and the increase of the curing degree in the CECF/GFRP composite. The in-plane shear modulus and interlaminar shear strength (ILSS) of the CECF/GFRP composite were 12.2% and 13.7% higher than those of the GFRP composite, respectively, indicating the enhanced deformation resistance and interfacial adhesion of the interlayer region. The compressive strength of the CECF/GFRP composite was increased by 14.1% relative to the GFRP composite, which was ascribed to restricted kink-band and delayed delamination damage during the compression process of composite.
        4,000원
        7.
        2025.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigates of repeated freeze-thaw (FT) cycles on the color, pH, and oxidative stability of vacuum-packaged chicken thigh meat. Samples were evaluated at Fresh, Frozen (2 weeks), FT1 (2-times FT, 4 weeks), and FT2 (3-times FT, 6 weeks). FT1 resulted in a higher pH, but the pH was slightly reduced in FT2. Oxidative stability declined with each cycle, as evidenced by significant increases in thiobarbituric acid reactive substances (TBARS), carbonyl content, and peroxide value (POV). Meanwhile, thiol content decreased notably. Color parameters were also affected by FT cycles. Redness (a* ) decreased in the frozen group but increased in subsequent cycles. Lightness (L* ) fluctuated, with a significant increase after FT2, and yellowness (b* ) showed slight increases and subsequent decreases. Chroma (c*) and hue angle (h°) also fluctuated due to repeated freeze-thaw cycles. Furthermore, correlation analysis revealed strong positive associations between TBARS, carbonyls, POV, and pH, while thiol content showed strong negative correlations with these oxidative markers, reinforcing the oxidative degradation trend. This comprehensive analysis illustrates the multifaceted impacts of freeze-thaw processes on the color, pH, and oxidation markers of chicken thigh meat, emphasizing the importance of understanding these effects for proper storage and safety.
        4,200원
        13.
        2025.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Alcohol is metabolized to acetaldehyde and acetate mainly by alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). Acetaldehyde accumulation is a key factor in hangover symptoms and alcohol-induced toxicity. In this study, we have investigated the effects of a Morning Care series on ethanol and acetaldehyde metabolism in male and female mice. Blood ethanol and acetaldehyde concentrations, ADH and ALDH activities in the blood and liver, and hepatic gene expression were measured at multiple time points after ethanol administration. EX PREMIUM, a hangover-relief beverage developed by Dong-A Pharm, significantly reduced blood ethanol and acetaldehyde concentrations and enhanced ADH and ALDH activities, accompanied by the upregulation of ADH and ALDH gene expression. These effects were consistently observed in both sexes. These results have suggested that EX PREMIUM effectively promotes alcohol metabolism, facilitates acetaldehyde clearance, and may contribute to alleviating alcohol-induced toxicity and hangover symptoms.
        4,000원
        16.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Conductive polymeric composites (CPC) incorporating carbon nanotubes (CNT) and carbon fibers (CF) offer promising potential in self-heating applications due to their superior electrical and thermal properties. This study investigates the synergistic effects of CNT and CF on the electrical conductivity and heat-generation capabilities of CNT/polydimethylsiloxane (PDMS) nanocomposites. Three CF lengths (0.1 mm, 3 mm, and 6 mm) were systematically evaluated to establish hierarchical conductive networks. The incorporation of 6 mm CF into CNT/PDMS composites resulted in a 72% increase in electrical conductivity compared to composites with 0.1 mm CF. Despite these enhancements in electrical performance, the heat-generation capabilities, based on simulations and experimental validation, showed minimal dependence on CF length. A micromechanics-based numerical approach was used to compare and validate the experimental findings, identifying limitations in current analytical models, especially in predicting the heat-generation behavior.
        4,300원
        17.
        2025.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lithium (Li) metal is a promising anode for next-generation batteries due to its high capacity, low redox potential, and low density. However, dendrite growth and interfacial instability limit its use. In this study, an artificial solid electrolyte interphase layer of LiF and Li-Sn (LiF@Li-Sn) was fabricated by spray-coating SnF2 onto Li. The LiF@Li-Sn anode exhibited improved air stability and electrochemical performance. Electrochemical impedance spectroscopy indicated a charge transfer resistance of 25.2 Ω after the first cycle. In symmetric cells, it maintained a low overpotential of 27 mV after 250 cycles at 2 mA/cm2, outperforming bare Li. In situ microscopy confirmed dendrite suppression during plating. Full cells with NMC622 cathodes and LiF@Li-Sn anodes delivered 130.8 mAh/g with 79.4% retention after 300 cycles at 1 C and 98.8% coulombic efficiency. This coating effectively stabilized the interface and suppressed dendrites, with promising implications for practical lithium metal batteries.
        4,000원
        18.
        2025.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 국제경영전략 관점에서 해외자회사가 이전한 지식은 기업 경쟁력 강화에 언제나 긍정 적일 것이라는 가정을 비판하기 위해, 해외자회사의 역지식이전 수준과 기업성과 간 관계를 분석하 였다. 글로벌 기업 직원 256명을 대상으로 설문조사한 결과, 해외자회사가 본사로 이전한 지식 수 준이 높을수록 높은 기업성과를 보이는 것으로 나타났다. 그러나 이러한 효과는 해외자회사의 역량 및 해외자회사와 본사 간 비전공유 수준에 따라 차이를 보이는 것으로 나타났으며, 해외자회사의 역량이 낮거나, 비전공유 수준이 낮은 조직의 역지식이전은 기업성과에 부정적 영향을 제공하는 것 으로 나타났다. 이를 통해 본 연구는 역지식이전 과정에서 글로벌 기업의 형태적 통제기제와 사회 적 통제기제가 요구되고 있음을 제시하였다.
        8,700원
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