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        검색결과 7

        1.
        2022.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a new method which constructs an Hi super-profile of a galaxy which is based on profile decomposition analysis. The decomposed velocity profiles of an Hi data cube with an optimal number of Gaussian components are co-added after being aligned in velocity with respect to their centroid velocities. This is compared to the previous approach where no prior profile decomposition is made for the velocity profiles being stacked. The S/N improved super-profile is useful for deriving the galaxy’s global Hi properties like velocity dispersion and mass from observations which do not provide sufficient surface brightness sensitivity for the galaxy. As a practical test, we apply our new method to 64 high-resolution Hi data cubes of nearby galaxies in the local Universe which are taken from THINGS and LITTLE THINGS. In addition, we also construct two additional Hi super-profiles of the sample galaxies using symmetric and all velocity profiles of the cubes whose centroid velocities are determined from Hermite h3 polynomial fitting, respectively. We find that the Hi super-profiles constructed using the new method have narrower cores and broader wings in shape than the other two super-profiles. This is mainly due to the effect of either asymmetric velocity profiles’ central velocity bias or the removal of asymmetric velocity profiles in the previous methods on the resulting Hi super-profiles. We discuss how the shapes (σn/σb, An/Ab, and An/Atot) of the new Hi super-profiles which are measured from a double Gaussian fit are correlated with star formation rates of the sample galaxies and are compared with those of the other two super-profiles.
        6,100원
        3.
        2022.04 구독 인증기관·개인회원 무료
        7.
        2018.04 구독 인증기관·개인회원 무료
        Buckwheat is well-known as a healthy crop with excellent nutritional and functional superiority mainly because of a high content of flavonoid compounds, specifically, rutin. However, buckwheat-based food products are known to have the reduced levels of rutin by rutin-degrading enzymes that generate quercetin during processing. However, since quercetin has a bitter taste, it may have a negative impact on consumer preferences, consequently retarding the utilization of buckwheat flour to a variety of buckwheat processed foods. Thus, this study was carried out to investigate the levels of rutin and quercetin in the milling fractions of buckwheat flours and also to monitor their changes by a variety of thermal treatments. Native buckwheat was separated into three fractions by sieving with 40 and 100 mesh screens which were designated as >40 M, 40-100 M, and 100 M<, respectively. The levels of rutin were the highest in the 40-100 M milling fraction, followed by <100 M and >40 M. Also, buckwheat flours were subjected to several thermal treatments including steaming and autoclaving. The contents of rutin and quercetin in the resulting buckwheat samples were analyzed by HPLC and the correlations between the flavonoid compounds and thermal treatments were investigated. The addition of water to buckwheat flour in making buckwheat products significantly decreased the levels of rutin while the quercetin content increased. However, the thermal treatments of buckwheat flours distinctly reduced the rutin loss and quercetin was hardly detected. Therefore, this study contributes to enhancing the health functionalities of buckwheat by reducing rutin loss, probably extending use of buckwheat flour to a variety of processed food products.