검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 1,458

        181.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The effect of heat treatment and vacuum conditions on the textural properties and electrochemical performance of commercially available activated carbons (ACs) was investigated. The AC after post-heat treatment was characterized by nitrogen adsorption–desorption, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, and Fourier-transform infrared spectroscopy measurements. The ACs treated under vacuum conditions exhibit a higher specific surface area and micropore surface area than those treated under nitrogen atmospheric pressure without significantly affecting the graphite structure of the AC. Under 800 °C temperature and vacuum conditions (AC-V800), the AC with the highest Brunauer– Emmett–Teller surface area of 1951.9 m2 g−1 (16.4% improvement relative to that of the original AC (1677.2 m2 g−1)) was obtained. This is attributed to the removal of oxygen-containing functional groups and volatile matters in the carbon by thermal treatment under vacuum conditions. Consequently, the electric double-layer capacitor using ACs treated under vacuum conditions (1 kPa) at 800 °C (AC-V800) shows considerably improved electrochemical performance in terms of higher specific capacitance and better cycling stability at a high working voltage (3.1 V), compared to the nitrogen-treated and commercial ACs.
        4,300원
        192.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Graphene fiber is considered as a potential material for wearable applications owing to its lightness, flexibility, and high electrical conductivity. After the graphene oxide (GO) solution in the liquid crystal state is assembled into GO fiber through wet spinning, the reduced graphene oxide (rGO) fiber is obtained through a reduction process. In order to further improve the electrical conductivity, herein, we report N, P, and S doped rGO fibers through a facile vacuum diffusion process. The precursors of heteroatoms such as melamine, red phosphorus, and sulfur powders were used through a vacuum diffusion process. The resulting N, P, and S doped rGO fibers with atomic% of 6.52, 4.43 and 2.06% achieved the higher electrical conductivities compared to that of rGO fiber while preserving the fibrious morphology. In particular, N doped rGO fiber achieved the highest conductivity of 1.11 × 104 S m−1, which is 2.44 times greater than that of pristine rGO fiber. The heteroatom doping of rGO fiber through a vacuum diffusion process is facile to improve the electrical conductivity while maintaining the original structure.
        4,000원
        193.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이끼의 분쇄번식 시, 가장 적합한 배양토, 광, 온도를 구명 하기 위해 날개양털이끼(Brachythecium plumosum)와 쥐꼬리이끼(Myuroclada maximowiczii)를 이용하여 실험을 수행하였다. 실험 개시 4주 후에 사진을 찍어 Photoshop에서 이끼 면적과 녹색 평균값을 구하여 이끼의 생육 정도를 나타내었다. 배양토의 경우, 두 이끼 모두 다스란 상토에서 생육이 가장 좋았고, 상토:마사토(50:50), 원예상토, 마사토:피트모스(50:50) 에서는 비슷한 수준이었다. 버미큘라이트 단용에서는 생육이 부진하였다. 광도실험에서는 날개양털이끼는 25umol・m-2・s-1 에서 100umol・m-2・s-1까지 광도가 높아질수록 생육이 조금씩 좋아지는 경향이었으나, 쥐꼬리이끼는 3개의 광환경에서 비슷한 수준이었다. 온도 실험에서는 두 이끼 모두 23℃에서 면적과 녹색값이 가장 높아 생육도 좋았다. 이러한 결과를 종합 하면, 건조한 이끼를 분쇄하여 번식할 때, 배양토로는 보습력이 좋은 다스란 상토나 원예용 상토가 무난하며, 광도는 25~100umol・m-2・s-1 범위, 온도는 20~23℃가 적당할 것으로 판단된다.
        4,000원