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        검색결과 15

        1.
        2023.10 구독 인증기관·개인회원 무료
        4.
        2022.10 구독 인증기관·개인회원 무료
        9.
        2016.10 구독 인증기관·개인회원 무료
        10.
        2014.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The main site of dust formation is believed to be the cool envelopes around AGB stars. Nearly all AGB stars can be identified as long-period variables (LPVs) with large amplitude pulsation. Shock waves produce by the strong pulsation and radiation pressure on newly formed dust grains drive dusty stellar winds with high mass-loss rates. IR observations of AGB stars identify various dust species in different physical conditions. Radio observations of gas phase materials are helpful to understand the overall properties of the stellar winds. In this paper, we review (i) classification of AGB stars; (ii) IR two-color diagrams of AGB stars; (iii) pulsation of AGB stars; (iv) dust around AGB stars including dusty stellar winds; (v) dust envelopes around AGB stars; (vi) mass-loss and evolution of AGB stars; and (vii) contribution of AGB dust to galactic environments. We discuss various observational evidences and their theoretical interpretations.
        4,800원
        11.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The International Olympiad on Astronomy and Astrophysics (IOAA) initiated by the Thailand Astronomical Society in 2007 is an annual competition for high school students. One of its aim is to enhance the development of international exchange in the field of school education in astronomy and astrophysics. This paper first provides the overview of the IOAA in terms of key regulations based on its statutes, history and current status. Secondly, the published syllabus of the IOAA is used for content analysis according to subject areas regarding the exam questions of the IOAA in theoretical, observational and data analysis parts from 2007 to 2010. Also, a scientific inquiry framework is applied to the same questions for assessment based on scientific inquiry in the cognitive aspect with two sub-classes of scientific knowledge and scientific reasoning. Among a dozen astronomy subject areas listed on the syllabus, the theoretical part of the IOAA makes more frequent use of the Sun, the solar system, properties of stars, and concept of time. In content knowledge, a factor of scientific knowledge, the IOAA questions, especially in the theoretical part have a lesser degree in difficulty than the IAO (International Astronomy Olympiad) exam questions for the same period whose degree in difficulty is comparable to college level. With regard to scientific reasoning, the IOAA questions tend to involve convergent rather than divergent thinking. Lastly, in light of these findings, discussions are given on the outcome of Korean participation in the previous IOAAs and ways to help better in preparing Korean students for future astronomy Olympiads.
        4,500원
        13.
        2009.04 구독 인증기관·개인회원 무료
        14.
        2001.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The advent of robust, reliable and accurate higher order Godunov schemes for many of the systems of equations of interest in computational astrophysics has made it important to understand how to solve them in multi-scale fashion. This is so because the physics associated with astrophysical phenomena evolves in multi-scale fashion and we wish to arrive at a multi-scale simulational capability to represent the physics. Because astrophysical systems have magnetic fields, multi-scale magnetohydrodynamics (MHD) is of especial interest. In this paper we first discuss general issues in adaptive mesh refinement (AMR), We then focus on the important issues in carrying out divergence-free AMR-MHD and catalogue the progress we have made in that area. We show that AMR methods lend themselves to easy parallelization. We then discuss applications of the RIEMANN framework for AMR-MHD to problems in computational astophysics.
        4,000원
        15.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The problem of the origin of cosmic rays is considered in an astronomical context and the current observational situation summarised. The evidence for acceleration in supernova remnants is critically examined.
        3,000원