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        검색결과 35

        5.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We estimate the fractal dimension of the ρ Ophiuchus Molecular Cloud Complex, associated with star forming regions. We selected a cube (v, l, b) database, obtained with J = 1−0 transition lines of 12CO and 13CO at a resolution of 22′′ using a multibeam receiver system on the 14-m telescope of the Five College Radio Astronomy Observatory. Using a code developed within IRAF, we identified slice-clouds with two threshold temperatures to estimate the fractal dimension. With threshold temperatures of 2.25 K (3σ) and 3.75 K (5σ), the fractal dimension of the target cloud is estimated to be D = 1.52–1.54, where P / AD/2 , which is larger than previous results. We suggest that the sampling rate (spatial resolution) of observed data must be an important parameter when estimating the fractal dimension, and that narrower or wider dispersion around an arbitrary fit line and the intercepts at NP = 100 should be checked whether they relate to rms noise level or characteristic structure of the target cloud. This issue could be investigated by analysing several high resolution databases with different quality (low or moderate sensitivity).
        4,000원
        13.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We present a multi-dimensional reduction method of the surveyed cube database obtained using a single- dish radio telescope in Taeduk Radio Astronomy Observatory (TRAO). The multibeam receiver system installed at the 14 m telescope in TRAO was not optimized at the initial stage, though it became more stabilized in the following season. We conducted a Galactic Plane survey using the multibeam receiver system. We show that the noise level of the first part of the survey was higher than expected, and a special reduction process seemed to be definitely required. Along with a brief review of classical methods, a multi-dimensional method of reduction is introduced; It is found that the ‘background’ task within IRAF (Image Reduction and Analysis Facility) can be applied to all three directions of the cube database. Various statistics of reduction results is tested using several IRAF tasks. The rms value of raw survey data is 0.241 K, and after primitive baseline subtraction and elimination of bad channel sections, the rms value turned out to be 0.210 K. After the one-dimensional reduction using ‘background’ task, the rms value is estimated to be 0.176 K. The average rms of the final reduced image is 0.137 K. Thus, the image quality is found to be improved about 43% using the new reduction method.
        4,000원
        14.
        2009.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        A method of estimating the lower bound of coronal magnetic field strength in the neighborhood of an ejecting plasmoid is presented. Based on the assumption that the plasma ejecta is within a magnetic island, an analytical expression for the force acting on the ejecta is derived. The method is applied to a limb coronal mass ejection event, and a lower bound of the magnetic field strength just below the CME core is estimated. The method is expected to provide useful information on the strength of reconnecting magnetic field if applied to X-ray plasma ejecta.
        4,000원
        20.
        2003.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 알팔파 Vernal(대조품종), Anchor, P5444, DK120, DK125, Horizon, DK135, 루나및 기타와카바 9품종을 축산기술연구소 대관령지소(표고 800m)와 남원지소(표고 450m)에서각각 난괴법 3반복으로 수행하였다. 알팔파의 엽폭은 Vernal을 제외하고 모든 품종이 대형이었으며 개화기는 DK125가 가장 빨랐다. 초고는 Luna품종이 가장 컸으며 내한성은 P5444가 80.2%로 가장 높았다. 알팔파의 건물수량은
        4,000원
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