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        검색결과 13

        1.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic in ation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.
        3,000원
        2.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to the lack of an accretion disk in a polar (magnetic cataclysmic variable, MCV), the material transferred from the secondary is directly accreted onto the white dwarf, forming an accretion stream and a hot spot on the white-dwarf component. During the eclipses, different light components can be isolated. Therefore, the monitoring of eclipsing polars could provide valuable information on several modern astrophysical problems, e.g., CVs as planetary hosting stars, mass transfer and mass accretion in CVs, and the magnetic activity of the most rapidly rotating cool dwarfs. In the past five years, we have monitored about 10 eclipsing polars (e.g., DP Leo and HU Aqr) using several 2-m class telescopes and about 100 eclipse profiles were obtained. In this paper, we will introduce the progress of our research group at YNOs. The first direct evidence of variable mass transfer in a CV is obtained and we show that it is the dark-spot activity that causes the mass transfer in CVs. Magnetic activity cycles of the cool secondary were detected and we show that the variable mass transfer is not caused by magnetic activity cycles. These results will shed light on the structure and evolution of close binary stars (e.g., CVs and Algols).
        3,000원
        3.
        2009.08 구독 인증기관·개인회원 무료
        An in vitro study was conducted to investigate the effect of propionate precursor (malate or fumarate) on fermentation characteristics, production of conjugated linoleic acid (CLA) and methane (CH₄) by rumen microbes when incubated with linoleic acid (C18:2) as a CLA precursor. Total CH₄ production for 12h incubation, however, was greatly reduced (P<0.0001) by all the supplements compared to that of control, and its production from M-LA or F-LA treatment was smaller than that from LA treatment. Supplementation of M-LA or F-LA also increased concentrations of cis9, trans11-CLA (P<0.039 - P<0.001) for all incubation times and trans10,cis 12-CLA at 1h (P<0.013), 3h(P<0.036) and 12h (P<0.025) incubation times compared to LA supplementation.
        4.
        2006.04 구독 인증기관·개인회원 무료
        Micro-porous nickel (Ni) with an open cell structure was fabricated by powder metallurgy. The pore size of the micro-porous Ni approximated and . For comparison, porous Ni with a macro-porous structure were also prepared by both powder metallurgy (pore size ) and the traditional chemical vapour deposition method (pore size ). The mechanical properties of the micro-and macro-porous Ni samples were evaluated using compressive tests. Results indicate that the micro-porous Ni samples exhibited significantly enhanced mechanical properties, compared to those of the macro-porous Ni samples.
        5.
        2006.04 구독 인증기관·개인회원 무료
        The nanoparticles were synthesized by photochemical deposition in a suspension system. The prepared products were characterized by means of XRD, Uv-vis and photoluminescence spectra (PL). Its photocatalytic activity was investigated by the decomposition of methylene blue (MB) solution under illumination of visible and ultraviolet light, respectively. Compared to , the photocatalytic activity of the as-prepared is obviously enhanced due to the decreasing recombination of a photoexcitated electron-hole pairs. The Mechanism in which photocatalytic activity is enhanced has been discussed in detail.
        6.
        2005.12 구독 인증기관 무료, 개인회원 유료
        This study was carried out to evaluate the effects of washing medium, breed and washing temperature of fresh and frozen-thawed boar sperm on mitochondrial activity and membrane integrity by flow cytometry. More than 80% of fresh sperm washed with mTLP-PVA medium at 20℃ exhibited an intact membrane and a functional mitochondrion. With frozen-thawed samples, a large number of sperm showed both damaged membrane (36.4~46.9%) and nonfunctional mitochondrion (55.1~71.1%) in the mTLP-PVA and BTS washing media at 20℃. There were no breed effects of fresh and frozen-thawed sperm on mitochondrial activity and membrane integrity. The percentages of damaged membrane of fresh and frozen sperm, respectively, were higher at 4℃ washing temperature than at 20℃ washing temperature in the mTLP-PVA medium. We found that washing medium and washing temperature of fresh and frozen-thawed boar sperm were important for the analyses of mitochondrial activity and membrane integrity by flow cytometry.
        4,000원
        7.
        2005.06 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        The 6th East Asian Meeting of Astronomy was held just at the time of 400 years after the discovery of SN (supernova) 1604 and its pre-maximum observation by the astronomers both from the East and the West in the 17th century. It has a special meaning and is interesting to look back on the historical observation of SN 1604. In this paper, we only limit to concern the Chinese observation on SN 1604.
        13.
        1996.12 KCI 등재 SCOPUS 구독 인증기관·개인회원 무료
        Based on the database of 128 disk galaxies (66 SO, 62 S and Irr) mailnly compiled from Kent and Gunn (1982) and Doi et a1.(1995) which is complete down to m < 15.6 mag within a radius of 3°, the orientation of spin vectors of disk galaxies of the Coma cluster has been analyzed. The results confirm the morphological dependence of the orientation of disk galaxies found from the analsis of the Virgo cluster. Common features of orientation of disk galaxies of both clusters are outlined.