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        검색결과 3,045

        704.
        2019.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper is to compare seafarers’ behavior according to traffic conditions of a road and an onshore locations. Behaviors are classified into three categories: Skill-, Rule- and knowledge-based mode. Experimental data were collected using the questionnaires for navigators, working in a merchant ship. To compare the behaviors, we used the four analysis method; the degree of frequency, reliability test, correlation and linear regression. As a result of the study, it was found that Skill-based behavior shows more higher in the road traffic than the maritime traffic, and rule-based behavior shows more higher in the maritime traffic than the road traffic. Also, the behavior in the navigation situation showed statistical significance. Especially, in the case of Rule-based behavior, a high correlation between road and maritime was found. This study can be expected to apply to complementary system utilization between error management system of onshore and maritime traffic.
        4,000원
        705.
        2019.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A triple-layered PMMA/Ni64Zr36/PDMS hydrogen gas sensor using hydrogen permeable alloy and flexible polymer layers is fabricated through spin coating and DC-magnetron sputtering. PDMS(polydimethylsiloxane) is used as a flexible substrate and PMMA(polymethylmethacrylate) thin film is deposited onto the Ni64Zr36 alloy layer to give a high hydrogenselectivity to the sensor. The measured hydrogen sensing ability and response time of the fabricated sensor at high hydrogen concentration of 99.9 % show a 20 % change in electrical resistance, which is superior to conventional Pd-based hydrogen sensors, which are difficult to use in high hydrogen concentration environments. At a hydrogen concentration of 5 %, the resistance of electricity is about 1.4 %, which is an electrical resistance similar to that of the Pd77Ag23 sensor. Despite using low cost Ni64Zr36 alloy as the main sensing element, performance similar to that of existing Pd sensors is obtained in a highly concentrated hydrogen atmosphere. By improving the sensitivity of the hydrogen detection through optimization including of the thickness of each layer and the composition of Ni-Zr alloy thin film, the proposed Ni-Zr-based hydrogen sensor can replace Pd-based hydrogen sensors.
        4,000원
        706.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        One- and two-dimensional carbon nanomaterials were tested as adsorbents for the elimination of two anionic dyes, reactive red 2 and methyl orange, and the cationic dye methylene blue from aqueous solutions under the same conditions. Carbon nanomaterials performed well in the removal of dyes. Surface oxygenated groups in the nanomaterials improved the cationic dyes’ adsorption, but not the adsorption of the anionic dye. The interactions between nanomaterials and dyes were verified by infrared and Raman spectroscopy. The pseudo-second order kinetic model was better fitted to the kinetic experimental data than the Elovich and pseudo-first order models. The equilibrium adsorption data were best fitted by the Langmuir model. The dimensions and morphology of the carbon nanomaterials play an important role in the adsorption of the three dyes. The main mechanism of adsorption of anionic dyes is by the interactions of the aromatic rings of the dye structures and π delocalized electrons on carbon nanostructures; the adsorption of cationic dye is mainly due to electrostatic interactions.
        4,300원
        707.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Lignocellulosic materials such as agricultural residues have been identified as potential sustainable sources that can replace petroleum-based polymers. This study focused on the conversion of lignin extracted from bagasse to carbon fiber (CF) and cellulose nanocrystal (CNC). The highest extraction of lignin yield was achieved at 100 °C using 10% NaOH for 12 h. Carbon fibers were obtained by electro-spinning of bagasse lignin blended with polyvinyl alcohol (PVA) (11 wt/v %) followed by thermo-stabilization (250 °C) in an oxidizing atmosphere and further carbonization in an inert atmosphere (850 °C). Conventional hydrolysis process was used to extract cellulose nanocrystal from bagasse pulp. Morphological (scanning electron microscopy, SEM), spectral (Fourier transform infrared, FTIR) spectroscopy, elemental analysis, thermal characterization and surface area measurements have been carried out. Figures originated by SEM showed that CF ranges from 145 to 204 nm, while stabilized bagasse cellulose nanocrystal (SCNC) appeared as rod-shape like structure in the range of length 600–800 nm and diameter 5.33–19 μm. Characterization results revealed that CF exhibits microporous structure, while bagasse lignin and SCNC display mesoporous structure. In addition, the results proved that SCNC exhibits a percentage removal 71.56% for methylene blue dye in an aqueous solution.
        4,000원
        712.
        2019.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The New Vacuum Solar Telescope (NVST) is the largest solar telescope in China. When using CCDs for imaging, equal-thickness fringes caused by thin-film interference can occur. Such fringes reduce the quality of NVST data but cannot be removed using standard flat fielding. In this paper, a correction method based on multi-scale decomposition and adaptive partitioning is proposed. The original image is decomposed into several sub-scales by multi-scale decomposition. The region containing fringes is found and divided by an adaptive partitioning method. The interference fringes are then filtered by a frequency-domain Gaussian filter on every partitioned image. Our analysis shows that this method can effectively remove the interference fringes from a solar image while preserving useful information.
        4,000원
        720.
        2019.04 구독 인증기관·개인회원 무료
        해외 수입농산물의 양이 점차적으로 증가하여 다양한 병해충의 유입 가능성이 증가함에 따라, 이들을 신속하고 정확하게 판별하기 위하여 DNA 염기서열을 이용하여 형태학적 동정을 보완하고 있다. 현재 바구미과의 Sternochetus속 에 속하는 관리해충은 S. mangiferae와 S. frigidus, 그리고 S. olivieri가 있으며, 태국에서 수입된 망고에서 2018년 9월부터 2019년 1월까지 7차례에 걸쳐 바구미류가 검출되었고, 형태학적 형질 및 DNA 바코드를 이용하여 S. olivieri로 동정하였다. 추가로, Sternochetus속에 속하는 종들의 분류학적 형질을 이용하여 동정의 수단을 제공하였다. 본 연구결 과는 수입 및 반입되는 망고에서 검출되는 바구미류의 신속하고 정확한 진단에 활용될 수 있을 것으로 판단된다.