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        검색결과 2,016

        184.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Korea Astronomy and Space Science Institute plans to develop a coronagraph in collaboration with National Aeronautics and Space Administration (NASA) and to install it on the International Space Station (ISS). The coronagraph is an externally occulted one-stage coronagraph with a field of view from 3 to 15 solar radii. The observation wavelength is approximately 400~nm, where strong Fraunhofer absorption lines from the photosphere experience thermal broadening and Doppler shift through scattering by coronal electrons. Photometric filter observations around this band enable the estimation of 2D electron temperature and electron velocity distribution in the corona. Together with a high time cadence ($<$12~min) of corona images used to determine the geometric and kinematic parameters of coronal mass ejections, the coronagraph will yield the spatial distribution of electron density by measuring the polarized brightness. For the purpose of technical demonstration, we intend to observe the total solar eclipse in August 2017 with the filter system and to perform a stratospheric balloon experiment in 2019 with the engineering model of the coronagraph. The coronagraph is planned to be installed on the ISS in 2021 for addressing a number of questions (e.g., coronal heating and solar wind acceleration) that are both fundamental and practically important in the physics of the solar corona and of the heliosphere.
        4,200원
        185.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon-based magnetic nanostructures in several instances have resulted in improved physicochemical and catalytic properties when compared to multi-wall carbon nanotubes (MWCNTs) and magnetic nanoparticles. In this study, magnetic MWCNTs with a structure of NixZnxFe2O4/MWCNT as peroxidase mimics were fabricated by the one-pot hydrothermal method. The structure, composition and morphology of the nanocomposites were characterized with X-ray diffraction (XRD), Fourier transform infrared spectroscopy and transmission electron microscopy. The magnetic properties were investigated with a vibrating sample magnetometer. The peroxidase-like catalytic activity of the nanocomposites was investigated by colorimetric and electrochemical tests with 3,3´,5,5´-tetramethylbenzidine (TMB) and H2O2 as the substrates. The results show that the synthesis of the nanocomposites was successfully performed. XRD analysis confirmed the crystalline structures of the NixZnxFe2O4/ MWCNT nanohybrids and MWCNTs. The main peaks of the NixZnxFe2O4/MWCNTs crystals were presented. The Ni0.25Zn0.25Fe2O4/MWCNT and Ni0.5Zn0.5Fe2O4/MWCNT nanocatalysts showed nearly similar physicochemical properties, but the Ni0.5Zn0.5Fe2O4/MWCNT nanocatalyst was more appropriate than the Ni0.25Zn0.25Fe2O4/MWCNT nanocatalyst in terms of the magnetic properties and catalytic activity. The optimum peroxidase-like activity of the nanocatalysts was obtained at pH 3.0. The Ni0.5Zn0.5Fe2O4/MWCNT nanocatalyst exhibited a good peroxidase-like activity. These magnetic nanocatalysts can be suitable candidates for future enzyme-based applications such as the detection of glucose and H2O2.
        4,000원
        190.
        2017.10 구독 인증기관·개인회원 무료
        192.
        2017.10 구독 인증기관·개인회원 무료
        Research on the useful mushroom was done at Aurora Memorial National Park (AMNP). The Park is situated in Central Luzon Region with a total land area of 5,676 hectares. AMNP has no distinct wet and dry season thus provides a favorable climate, which promotes the growth of useful mushrooms. The photo-documentation and collections were performed to assess diversity. Five Transect Lines (TL) were laid out in five areas, with 20m x 30m quadrat and interval of 100 meters between quadrats. The study resulted in the identification of 36 families, 53 genera, and 104 species of which 97 are basidiomycetes and 6 are ascomycetes. Simpson’s and Shannon diversity indexes resulted in 0.7254 and 1.4295, respectively. In both indexes, useful mushrooms at AMNP showed moderately diverse. While the evenness revealed 0.1565 indicating low species evenness in each TL. Among the significant findings revealed two new possible new species of Microporus and Cymatoderma.
        193.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to estimate the effect of home or hetero fermentative lactic acid bacteria(LAB) on chemical composition, fermentation quality, and aerobic stability of rye silage. Rye forage was harvested at dough stage(28.9% of dry matter), chopped to 3-5 cm length, and divided into 4 piles for different inoculations as treatment, following 1) No additives(CON); 2) Lactobacillus plantarum at rate of 1.5 x 105 cfu/g of fresh forage(LP); 3) L. buchneri at rate of 1.2 x 105 cfu/g of fresh forage(LB); and 4) Mixture of LP and LB at 1:1 ratio(MIX). Rye silage was ensiled into 20 L bucket silo in quadruplicate for 0, 1, 4, 7, and 100 day periods. After 100 days of ensiling, the silage treated with LB had lower acid detergent fiber content(p<0.05), but higher in vitro dry matter digestibility(p<0.05). The LB and MIX reduced (p<0.05) pH more rapidly than CON and LP across the ensiling days, but had no difference on 100 days. Silage treated LP had lowest(p<0.05) acetic acid, but highest(p<0.05) propionic acid. In contrast, LB treated silage had highest(p<0.05) acetic acid, but lowest(p<0.05) propionic acid with the absence of butyric acid. On microbial count, LP treated silage had lowest(p<0.05) LAB, yeast, and aerobic stability, whereas LB and MIX treated silages had highest(p<0.05). Mold was not detected across all silages. Therefore, it could be concluded that heterofermentative LAB solely or combo with homofermentative LAB might improve in vitro dry matter digestibility, fermentation characteristics, and aerobic stability of rye silage harvested at dough stage.
        4,000원