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        검색결과 28

        1.
        2021.10 구독 인증기관·개인회원 무료
        3.
        2019.04 구독 인증기관·개인회원 무료
        10.
        2015.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The symbiotic star V1016 Cygni, a detached binary system consisting of a hot white dwarf and a mass-losing Mira variable, shows very broad emission features at around 6825 °A and 7082 °A, which are Raman scattered Ovi  1032, 1038 by atomic hydrogen. In the high resolution spectrum of V1016 Cyg obtained with the Bohyunsan Optical Echelle Spectrograph these broad features exhibit double peak profiles with the red peak stronger than the blue counterpart. However, their profiles differ in such a way that the blue peak of the 7082 feature is relatively weaker than the 6825 counterpart when the two Raman features are normalized to exhibit an equal red peak strength in the Doppler factor space. Assuming that an accretion flow around the white dwarf is responsible for the double peak profiles, we attribute this disparity in the profiles to the local variation of the flux ratio of Ovi  1032, 1038 in the accretion flow. A Monte Carlo technique is adopted to provide emissivity maps showing the local emissivity of Ovi 1032 and Ovi 1038 in the vicinity of the white dwarf. We also present a map indicating the differing flux ratios of Ovi  1032 and 1038. Our result shows that the flux ratio reaches its maximum of 2 in the emission region responsible for the central trough of the Raman feature and that the flux ratio in the inner red emission region is almost 1. The blue emission region and the outer red emission region exhibit an intermediate ratio around 1.5. We conclude that the disparity in the profiles of the two Raman Ovi features strongly implies accretion flow around the white dwarf, which is azimuthally asymmetric.
        4,000원
        13.
        2014.10 구독 인증기관·개인회원 무료
        17.
        2011.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the results of our high resolution optical spectroscopic monitoring campaign (⋋ = 3800 ~ 8800 Å, R = 30000 - 45000) of the new FU Orionis-type object HBC 722. We observed HBC 722 with the BOES 1.8-m telescope between November 26 and December 29, 2010, and FU Orionis itself on January 26, 2011. We detect a number of previously unreported high-resolution K I and Ca II lines beyond 7500 Å. We resolve the Hα and Ca II line profiles into three velocity components, which we attribute to both disk and outflow. The increased accretion during outburst can heat the disk to produce the relatively narrow absorption feature and launch outflows appearing as high velocity blue and red-shifted broad features.
        4,000원
        18.
        2010.10 구독 인증기관·개인회원 무료
        Cuticular hydrocarbons (CHCs) were analyzed using GC and GC-MS, and compared with developmental stages of the Lycorma delicatula. Total Carbon numbers on all developmental stages are 21-36, and composition numbers are 51. On the whole, Carbon numbers increased as passed times on developmental stages. Except for eggs, Lycorma delicatula consisted of n-heptacosane on almost all developmental stages, and followed by n-nonacosane. Eggs, however, consisted of 9-; 11-; 13- methylheptacosane. From the above results, CHCs on developmental stages of the Lycorma delicatula consisted of n-alkane with saturated hydrocarbons (36%), followed mono- (34%) or di- (21%) methylalkanes. Above this, CHCs consisted of tri- methylalkanes (3.9%) and olefines (2.3%) that have double bond. The major constituents of CHCs on the developmental stages of Lycorma delicatula is differently proportioned, but hardly showed the difference in their composition.
        19.
        2010.05 구독 인증기관·개인회원 무료
        Cuticular hydrocarbons (CHCs) were analyzed using GC and GC-MS, and compared with developmental stages of the bean bug, Riptortus pedestris. Carbon numbers on each developmental stages differed from 14-19 in eggs to 4th nymph, 25 in 5th nymph, and over 30 in last nymph that until adult emergence. Carbon numbers are increased to 16-17 carbons over time in newly emerged adults, 18-22 in 1 and 3 days after emergence, respectively; 23-27 in 6 days after emergence; approximately 30 in over 10 days after emergence. Carbon numbers increased as passed days after emergence. Riptortus pedestris consisted of n-nonacosane on almost all developmental stages, and followed by n-hentriacontane and 13,17-;15,19-demethyltritriacontane. Eggs, however, consisted of unknown compounds with high proportion and followed by n-heptacosane, and newly emerged adults also has a high proportion of n-heptacosane. From the above results, CHCs on developmental stages of the bean bug consist of n-alkane with saturated hydrocarbons (36-65 %), followed mono- or di- methylalkanes. However, newly emerged female and male adults mostly consisted of methyl-alkane. The major constituents of CHCs on the developmental stages of Riptortus pedestris is differently proportioned, but hardly showed the difference in their composition.
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