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        검색결과 3

        1.
        2023.05 구독 인증기관 무료, 개인회원 유료
        With the rapid development of the Internet, mobile Internet, big data, cloud computing and other technologies as well as the continuous improvement of logistics infrastructure, cross-border e-commerce has been developing rapidly in China. As a close neighbor of South Korea, the development of crossborder e-commerce has given wings to the development of trade between China and South Korea. Shandong Province, as an eastern coastal city of China, has a unique advantage in trade with Korea. In this paper, we will study the current situation of trade development between Shandong and Korea, analyze its problems, and put forward corresponding countermeasures and suggestions.
        4,000원
        2.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The evolvement in the microstructure and electrical properties of PAN-based carbon fibers during high-temperature carbonization were investigated. The study showed that as the heat treatment temperature increases, the change of carbon fiber resistivity around 1100 °C can be divided into two stages. In the first stage, the carbon content of the fiber increased rapidly, and small molecules such as nitrogen were gradually released to form a turbostratic of carbon crystal structure. The resistivity dropped rapidly from 3.19 × 10− 5 Ω·m to 2.12 × 10− 5 Ω·m. In the second stage, the carbon microcrystalline structure gradually became regular, and the electron movement area gradually became larger. At this time, the resistivity further decreases, from 2.12 × 10− 5 Ω·m to 1.59 × 10− 5 Ω·m. During carbonization, the tensile strength of carbon fiber first increased and then decreased. This is because the irregular and disordered graphite structure is formed first. As the temperature rose, the graphite layer spacing decreased and the grain thickness gradually increases. The modulus also gradually increased.
        4,000원