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        검색결과 158

        102.
        2000.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We have developed a near real-time flare alerting system which (1) downloads the latest GOES-l0 1-8 Å X-ray flux 1-min data by an automated ftp program and shell scripts, (2) produces a beep sound in a simple IDL widget program when the flux is larger than a critical value, and (3) makes it possible to do a wireless alerting by a set of portable transceivers. Thanks to the system, we have made successful Ha flare observations by the Solar Flare Telescope in Bohyunsan Optical Astronomy Observatory. This system is expected to be helpful for ground-based flare observers.
        3,000원
        106.
        2000.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Coal tar pitch was chemically modified with 10 wt% benzoquinone (BQ) to raise the softening point of isotropic pitch precursor and the precursor was melt-spun into pitch fibers, stabilized, carbonized and activated with steam at 900℃. The weight loss of carbon fiber-benzoquinone (CF-BQ) increased with the increase of activation time like other fibers, but was lower than those of Kureha fiber at the same activation time in spite of larger geometric surface area. Those adsorption isotherms fitted into 'Type I' according to Brunauer, Deming, Deming and Teller classification. However, there was very thin low-pressure hysteresis that lower closure points of the hysteresis are about 0.42-0.45. From the pore size distribution curves, there might be some micropores having narrow-necked bottle; a series of interconnected pore is more likely than discrete bottles. FT-IR studies showed that the functional groups such as carboxyl, quinone, and phenol were introduced to ACFs-BQ surface after steam activation. Methylene blue decolorization and iodine adsorption capacity of ACF-BQ increased linearly with the increase of specific surface area and was larger than that of ACF-Kureha at the same specific surface area.
        4,000원
        107.
        2000.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nonpotential characteristics of magnetic fields in AR 5747 are examined using Mees Solar Observatory magnetograms taken on Oct. 20, 1989 to Oct. 22, 1989. The active region showed such violent flaring activities during the observational span that strong X-ray flares took place including a 2B/X3 flare. The magnetogram data were obtained by the Haleakala Stokes Polarimeter which provides simultaneous Stokes profiles of the Fe I doublet 6301.5 and 6302.5. A nonlinear least square method was adopted to derive the magnetic field vectors from the observed Stokes profiles and a multi-step ambiguity solution method was employed to resolve the 180° ambiguity. From the ambiguity-resolved vector magnetograms, we have derived a set of physical quantities characterizing the field configuration, which are magnetic flux, vertical current density, magnetic shear angle, angular shear, magnetic free energy density, a measure of magnetic field discontinuity MAD and linear force-free coefficient. Our results show that (1) magnetic nonpotentiality is concentrated near the inversion line in the flaring sites, (2) all the physical parameters decreased with time, which may imply that the active region was in a relaxation stage of its evolution, (3) 2-D MAD has similar patterns with other nonpotential parameters, demonstrating that it can be utilized as an useful parameter of flare producing active region, and (4) the linear force-free coefficient could be a evolutionary indicator with a merit as a global nonpotential parameter.
        4,000원
        115.
        1998.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 GnRH가 과배란 처치된 래트의 초기 난포기와 후기 난포기에서 난소기능에 어떠한 영향을 미치는지를 이해하기 위해서, 30IU PMSG와 10IU hCG로 전처치된 미성숙 래트에 있어서 배란반응, 배란 난자의 형태학적 이상 유무 및 핵 성숙도, 난소 중량, 난소의 조직학적인 변화 및 혈중 스테로이드 호르몬 (17-estradiol, progesterone 및 testosterone) 농도에 대하여 GnRH agonist의 효과를 검사하였다.
        4,800원
        119.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        In the present study we examine physical characteristics of a thin and rigid magnetic flux tube with a steady flow inside, which is embedded vertically upward in the solar atmosphere. We found from this study that (1) The downward material flow gives rise to a dominant heating in the flux tube which works with the conductive heating in the same direction. However, the upflow flow creates a dominant cooling which works against the conductive heating, resulting in a steeper temperature gradient with a shallower transition region. (2) Since the thickness of the transition region determines the material content in the transition region, a broader transition region of the downflow tube produces a larger differential measure.
        120.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        In the present work we introduce a new flare activity indicator, MAD and examine its characteristics by analyzing a set of successive three days' observations of a typical active region, AR2372. The computed MAD is compared with conventional activity indicator such as separator. It is found that. (1) MAD traces very well the separator, (2) it. singles out. local discontinuity of magnetic field lines and (3) it. is a good measure of describing the evolutionary status of active region.
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