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        검색결과 139

        86.
        2004.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        An imaging spectrograph concept optimized for extended far-ultraviolet emission sources is presented. Although the design was originally developed for FIMS aboard the first Korean science satellite STSAT-l launched on September 27, 2003, no rigorous theoretical background of the spectrograph design has been published. The spectrograph design employs an off-axis parabolic cylinder mirror in front of a slit that guides lights to a diffraction grating. The concave grating provides moderate spatial resolution over a large field of view. This mapping capability is absent in most astronomical instruments but is crucial to the understanding of the nature of a variety of astrophysical phenomena. The aberration theory presented in this paper can be extended to holographic gratings in order to improve the spatial as well as the spectral resolutions.
        4,000원
        88.
        2003.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        89.
        2002.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Reballasting at sea, as recommended by the IMO guidelines, currently provides the best-available measure to reduce the risk of transfer of harmful aquatic organisms, but is subject to serious ship-safety limits. It is therefore extremely important that alternative, effective ballast water management and treatment methods are developed as soon as possible, to replace reballasting at sea. Filtration-Ultraviolet radiation-Electrolytic process (FUE) was evaluated for disinfection of seawater used In ballast water Optimal current density and UV light intensity were 2.0A/dm2 and, 220㎼/ cm2/m with which 100% reduction time was 2sec in a Ultraviolet radiation-Electrolytic process. This study showed that FUE process was effective for the disinfection of commonly isolated bacteria and bacillus from ballast water.
        4,000원
        90.
        2002.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Traditionally, ultraviolet (UV) has been used for treating the pressure sore and skin wound. The effects of UVA and UVB radiation on disinfection have been reported. The purpose of this study was to examine the effectiveness of UVC radiation on disinfection of Escherichia coli, Staphylococcus aureus, Salmonella typhimurium in vitro. Three bacterium were radiated by UVC (250 nm, 20 seconds) and incubated at for 24 hours at the agar culture medium. Kill rates of all three bacterium were 99.9%. UVC radiated on three kinds of bacterium for 30 or 60 seconds. Kill rates were 99.9% both 30 and 60 seconds. This data suggests that UV light at 250 nm could be a useful method to minimize infection and shorten healing time in pressure sore and skin wound condition.
        4,000원
        92.
        2001.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the effect of ultraviolet rays, soaking, boiling and baking to ergocalciferol (Vit.D2) and riboflavin(Vit.B2) contents of mushrooms, Lentinus edodes, Pleurotus ostreatus and Agaricus bisporus. The results were as follow: 1. Mushrooms were exposed to ultraviolet rays Lentinus edodes : 10J/cm2, Pleurotus ostratus : 2J/cm2 and Agaricus bisporus : 2J/cm2. 2. Before exposing to ultraviolet rays, the ergocalciferol contents of mushrooms were all 0μg/g dry base, but after exposing to it , those of Lentinus edodes, Pleurotus ostreatus and Agaricus bisporus were 222.50±5.30μg/g dry base, 150.90±6.60μg/g dry base and 23.98±1.20μg/g dry base, respectively 3. Before and after exposing to ultraviolet rays, the riboflavin contents of Lentinus edoes, Pleurotus ostreatus and Agaricus bisporus were 18.22±0.71μg/g dry base and 11.72±0.50μg/g dry base, 4.57±0.20μg/g dery base and 3.26±0.15μg/g dry base, and 37.42±1.20μg/g dry base and 27.33±2.10μg/g dry base, respectively. 4. The ergocalciferol contents of mushrooms according to boiling time were not significantly different but the riboflavin contents of them were decreased according to the increase of boiling time. 5. The ergocalciferol and riboflavin contents of mushrooms were decreased according to the increase of NaCl concentration and baking temperature. 6. The ergocalciferol content of Lentinus edodes after a short time soaking at 80℃ was higher than a long time soaking at 20℃, 40℃ and 60℃.
        4,000원
        93.
        2001.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this paper, we investigate the correlation between the radial ultraviolet color distribution and the shapes of the ultraviolet isophote for elliptical galaxies (M32, NGC 1399) and spiral bulges (of M31, M81) by using their archival UIT images. For M31, M81, and NGC 1399, the radial ultraviolet color distributions show a two-component trend; as the distance from the galactic center increase the color becomes redder in the inner region while it becomes bluer in the outer region. On the other hand, the color of M32 continues to become bluer with the increasing galactocentric distance. We also find, unlike the optical/IR images, significant variations of the position angle and the ellipticity in the ultraviolet isophotes of M31, M81, and NGC 1399 through the inner regions. For M32, the variation is significant in the outer region. Since these variation implies the triaxiality of their intrinsic shapes, we suggest that the early-type galaxies and spiral bulges with a radial color gradient in ultraviolet tend to have a triaxiality. On the other hand, the shape parameter characterized by the fourth order cosine Fourier coefficient of the isophote, a(4)/a, indicates that the systematic deviations of the ultraviolet isophotes of the four galaxies are smaller than ~0.2% in units of the semi-major axis. The latter result implies that the ultraviolet isophotes of the galaxies have a pure elliptical shape rather than the boxy or disky shapes. Therefore, there is no clear evidence of correlation between the radial ultra-violet color gradient and the boxy/disky shapes of isophotes.
        4,000원
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