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        검색결과 1,985

        1162.
        2015.10 구독 인증기관·개인회원 무료
        The family Scelionidae is distributed all around the world, which has approximately 3,000 species within 150 genera in the world. To date 39 species of 15 genera from 3 subfamilies in Scelionidae are recorded in South Korea. In this study, we report a new record of the genus Idiris with one species. There are many parasitory and predatory insects specializing on spider eggs. Among scelionids, some species (Baeus achaearneus, Comastichus zopheros, Idris sp.) parasitize spider eggs. However, there was no Korean record for scelionid wasps parasitizing in egg sacs of spider. Based on morphology, ecology, and DNA identification, we recognized this species, Idris sp., being new to Korea. All examined specimens and DNA samples are deposited in Kunsan National University.
        1163.
        2015.10 구독 인증기관·개인회원 무료
        The genus Toxares (Braconidae: Aphidiinae) is reported for the first time in Korea. Members of Toxares are known as solitary koinobiont endoparasitoids especially specific for aphidine aphids. In this study, Toxares deltiger (Haliday, 1833) is found as new to Korea, which has a wide host range for 31 aphid species within Aphidinae. Thus, this species would be useful as natural enemy for biological control in the future. Diagnosis and host information are included.
        1164.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Radio sources are very weak, as they can travel through large distances. Radio sources also have photons with low energies compared to others electromagnetic waves (EM). Microwave photons have a little more energy than radio waves, infrared photons have still more, then visible, ultraviolet, X-rays, and the most energetic electromagnetic wave is gamma-rays. Radio astronomy studies are restricted due to radio frequency interference (RFI) produced by people. If this disturbance is not minimized, it poses critical problems for astrophysical studies. The purpose of this paper is to profile RFI maps in Peninsular Malaysia with a minimum mapping technique for RFI interference. Decision-making processes using GIS (Geographical Information System) for the selection requires gathering information for a variety of parameters. These factors affecting the selection process are also taken into account. In this study, various factors or parameters are involved, such as the availability of telecommunications transmission (including radio and television), rainfall, water lines and human activity. This mapping step must be followed by RFI site testing in order to identify areas of low RFI. This study will benefit radio astronomy research, especially regarding the RFI profile.
        3,000원
        1165.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Hiroshima Astrophysical Science Center (HASC) was founded in 2004 at Hiroshima University, Japan. The main mission of this institute is the observational study of various transient objects includ- ing gamma-ray bursts, supernovae, novae, cataclysmic variables, and active galactic nuclei by means of multi-wavelength observations. HASC consists of three divisions; the optical-infrared astronomy divi- sion, high-energy astronomy division, and theoretical astronomy division. HASC is operating the 1.5m optical-infrared telescope Kanata, which is dedicated to follow-up and monitoring observations of transient objects. The high-energy division is the key operation center for the Fermi gamma-ray space telescope. HASC and the high-energy astronomy group in the department of physical science at Hiroshima University are closely collaborating with each other to promote multi-wavelength time-domain astronomy. We report the recent activities of HASC and some science topics pursued by this multi-wavelength collaboration.
        3,000원
        1166.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Kepler mission has shown that small planets are extremely common. It is likely that nearly every star in the sky hosts at least one rocky planet. We just need to look hard enough - but this requires vast amounts of telescope time. MINERVA (MINiature Exoplanet Radial Velocity Array) is a dedicated exoplanet observatory with the primary goal of discovering rocky, Earth-like planets orbiting in the habitable zone of bright, nearby stars. The MINERVA team is a collaboration among UNSW Australia, Harvard-Smithsonian Center for Astrophysics, Penn State University, University of Montana, and the California Institute of Technology. The four-telescope MINERVA array will be sited at the F.L. Whipple Observatory on Mt Hopkins in Arizona, USA. Full science operations will begin in mid-2015 with all four telescopes and a stabilised spectrograph capable of high-precision Doppler velocity measurements. We will observe ~100 of the nearest, brightest, Sun-like stars every night for at least five years. Detailed simulations of the target list and survey strategy lead us to expect 154 new low-mass planets.
        4,000원
        1167.
        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
        1168.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The high-order Laplacian-type filter, which is capable of providing isotropic and sharp cut-off filtering on the spherical domain, is essential in processing geophysical data. In this study, a spherical high-order filter was designed by combining the Fourier method with finite difference-method in the longitude and latitude, respectively. The regular grid system was employed in the filter, which has uniform angular spacing including the poles. The singularity at poles was eliminated by incorporating variable transforms and continuity-matching boundary conditions across poles. The high-order filter was assessed using the Rossby-Haurwitz wave, the observed geopotential, and observed wind field. The performance of the filter was found comparable to the filter based on the Galerkin procedure. The filter, employing the finite difference method, can be designed to give any target order of accuracy, which is an important advantage being unavailable in other methods. The computational complexity is represented with 2n-1 diagonal matrices solver with n being the target order of accuracy. Along with the availability of arbitrary target-order, it is also advantageous that the filter can adopt the reduced grid to increase computational efficiency.
        4,000원
        1169.
        2015.09 KCI 등재 구독 인증기관·개인회원 무료
        Quasars are among the farthest and brightest objects known in the universe. Because quasars are mostly observed in the redshift range between 1 and 3, they can be used to study large scale structure in the universe, and its evolution over the past billion years. An important issue is the evolution of the quasar luminosity function, which has been investigated for relative small samples of the 2QZ catalog. Here we extend the study to 3 quasar samples, the most recent data of the Milliquas, Master and 2QZ quasar catalogs to determine the luminosity function of quasars and its evolution, using the Standard cosmological ΛCDM model with ΩΛ = 0.73, ΩM = 0.27, and H0 = 70kms-1Mpc-1. For the purpose of this analysis we initially used 0.25-mag bins and approximately 0.180-redshift bins, then calculated the comoving distance and comoving volume for each bin of redshift and calculated the number of objects in each bin per unit volume, in order to find the number density per absolute magnitude bin. Our analysis on the basis of these new and much more complete datasets is largely in agreement with earlier studies of the luminosity evolution of quasars.
        1170.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        사우디아라비아 북부지역에서 수집된 홍화 총 100자원에 대 한 총폴리페놀 함량 및 항산화 활성을 평가하여 항산화활성이 높은 홍화자원을 선발하고자 연구를 수행하였으며 그 결과는 다음과 같다. 1. 총 100자원의 홍화유전자원에 대한 총폴리페놀 함량은 14.2 ± 0.41 μg GAE mg−1dw에서 81.6 ± 1.56μg GAEmg−1dw 까지 분포하였다. DPPH 라디컬 소거능은 1.6 ± 0.07 μg ASC mg−1 dw에서 14.1 ± 0.23 μg ASCmg−1 dw까지 활성을 나 타냈다. ABTS 활성은 34.5 ± 0.70 μg Trolox mg−1 dw에서 156.5 ± 3.06 μg Trolox mg−1 dw까지 평가되었다. 항산화활성 을 측정한 DPPH와 ABTS 활성간에는 상당한 유의성(r = 0.954**)을 보였다. 2. 홍화자원 100자원의 총폴리페놀 함량 및 항산화활성 결 과값에 대한 상호관계를 분석하여 활성이 높은 그룹(Group1)을 얻었다. Group1에 포함된 8개의 홍화자원은 나머지 그룹에 속한 자원들에 비해 항산화활성이 높았으며, 이중 K185841, K185879, K185863은 Group1내의 다른 자원들보다도 항산화 활성이 상당히 높아 홍화육종이나 기능성물질연구에 좋은 소 재가 될 것으로 사료된다.
        4,300원
        1171.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We study galaxies drawn from the semi-analytic models of Guo et al. (2011) based on the Millennium Simulation. We establish a set of four observationally measurable parameters which can be used in combination to identify a subset of galaxy groups which are old, with a very high probability. We therefore argue that a sample of fossil groups selected based on the luminosity gap will result in a contaminated sample of old galaxy groups. By adding constraints on the luminosity of the brightest galaxy, and its offset from the group luminosity centroid, we can considerably improve the age-dating.
        3,000원
        1172.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We use the millennium simulation for studying the evolution of groups of galaxies over time. We find fossil and non-fossil groups as well as old and young groups at redshift z = 0 and follow them back in time to investigate the evolution of their parameters, such as mass assembly, luminosity gap and halo mass concentration. We find that fossils assemble a larger fraction of their mass at z = 0 than controls. The magnitude gaps between fossil and non-fossil groups are not the same because of major and minor mergers, in old and young groups as well. We also find that WMAP1 and WMAP7 cosmologies lead to the same evolutionary history for fossil and control groups.
        3,000원
        1173.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have conducted a near-infrared monitoring campaign at the UK InfraRed Telescope (UKIRT), of the Local Group galaxy M33. The main aim was to identify stars in the very nal stage of their evolution, and for which the luminosity is more directly related to the birth mass than the more numerous less-evolved giant stars that continue to increase in luminosity. The pulsating giant stars (AGB and red supergiants) are identified and their distributions are used to derive the star formation rate as a function of age. These stars are also important dust factories; we measure their dust production rates from a combination of our data with Spitzer Space Telescope mid-IR photometry. The mass-loss rates are seen to increase with increasing strength of pulsation and with increasing bolometric luminosity. Low-mass stars lose most of their mass through stellar winds, but even super-AGB stars and red superginats lose ~40% of their mass via a dusty stellar wind. We construct a 2-D map of the mass-return rate, showing a radial decline but also local enhancements due to agglomerations of massive stars. By comparing the current star formation rate with total mass input to the ISM, we conclude that the star formation in the central regions of M33 can only be sustained if gas is accreted from further out in the disc or from circum-galactic regions.
        3,000원
        1174.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We use multi-wavelength observations of galaxy groups to probe the formation models for galaxy for- mation in cosmological simulations, statistically. The observations include Chandra and XMM-Newton X-ray observations, optical photometry and radio observations at 1.4 GHz and 610 MHz. Using a large sample of galaxy groups observed by the XMM-Newton X-ray telescope as part of the XMM-Large Scale Survey, we carried out a statistical study of the redshift evolution of the luminosity gap for a well de- fined mass-selected group sample and show the relative success of some of the semi-analytic models in reproducing the observed properties of galaxy groups up to redshift z ~ 1.2. The observed trend argues in favour of a stronger evolution of the feedback from active galactic nuclei at z < 1 compared to the models. The slope of the relation between the magnitude of the brightest cluster galaxy and the value of the luminosity gap does not evolve with redshift and is well reproduced by the models. We find that the radio power of giant elliptic galaxies residing in galaxy groups with a large luminosity gap are lower compared to giant ellipticals of the same stellar masses but in typical galaxy groups.
        4,000원
        1175.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We adopt the PASTEL catalog combined with SIMBAD radial velocities as a testing standard to validate the stellar parameters (effective temperature Teff , surface gravity log g, metallicity [Fe=H] and radial velocity Vr) from the first data release (DR1) of The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey. After applying data reduction and temperature constraints to the sample obtained by cross-identification, we compare the stellar parameters from DR1 and PASTEL. The results show that the DR1 results are reliable under certain conditions. We derive a dispersion of 110 K, 0.19 dex, 0.11 dex and 4.91 kms-1 in specified effective temperature ranges, for Teff , log g, [Fe=H] and Vr respectively. Systematic errors are negligible except for those of Vr. In addition, for stars with PASTEL [Fe=H] < —1.5, the metallicities in DR1 are systematically higher than those in PASTEL.
        3,000원
        1176.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국산 집게벌과의 미기록종인 발톱집게벌 (Conganteon nepalense Olmi) (신칭)과 짧은맥발톱집게벌 (Fiorianteon junonium Olmi) (신칭)을 확인하고, 그에 따라 미기록아과인 발톱집게벌아과 (Conganteoninae Olmi) (신칭)를 처음으로 보고한다. 검색표, 식별형질, 주요 형질에 대한 그림 및 사진을 함께 제시한다.
        4,000원
        1177.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We use ALLWISE data release W1- and W2-band epoch photometry collected by the Wide-Field Infrared Survey Explorer (WISE) to determine slopes of the period-luminosity relations for RR Lyrae stars in 15 globular clusters in the corresponding bands. We further combine these results with V- and K-band photometry of Galactic field RR Lyrae stars to determine the metallicity slopes of the log PF - [Fe/H]-MK, log PF - [Fe/H]-MW1, and log PF - [Fe/H]- MW2 period-metallicity-luminosity relations. We infer the zero points of these relations and determine the kinematical parameters of thick-disk and halo RR Lyraes via statistical parallax, and estimate the RR Lyrae-based distances to 18 Local-Group galaxies including the center of the Milky Way.
        4,000원
        1178.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        NGC147 and NGC185, paired satellites of the Andromeda galaxy, possess the same order of mass and analogous structures, but they show di erent star formation and different amounts of interstellar gas and dust. Therefore, we present the first reconstruction of the star formation history of NGC147 and NGC185. Asymptotic Giant Branch stars are highly evolved stars that are brightest in K-band. This maximum K-band magnitude is related to the birth mass of stars. As a result, we have found a 9.9 Gyrold single star formation epoch for NGC185 followed by relatively continuous star formation. NGC147, however, has passed through two star formation episodes; one is as old as ~6 Gyr and the other is as recent as 850 Myr. Asymptotic Giant Branch stars are also important dust factories; by fitting Spectral Energy Distributions to observed near and mid infrared data for each star, we were able to measure the dust production rates of individual stars; on order of 10-5M⊙yr-1. Hence, we estimate the total mass entering the interstellar medium to be 1.06 X 10-4M⊙ yr-1 and 2.89 X 10-4M⊙ yr-1 for NGC147 and NGC185.
        3,000원
        1179.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have carried out integral field unit (IFU) spectroscopy of Hα, [N ii] and [Oiii] emission lines for a sample of Galactic planetary nebulae (PNe) with Wolf-Rayet (WR) stars and weak emission-line stars (wels). Comparing their spatially-resolved kinematic observations with morpho-kinematic models allowed us to disentangle their three-dimensional gaseous structures. Our results indicate that these PNe have axisymmetric morphologies, either bipolar or elliptical. In many cases the associated kinematic maps for the PNe around hot central stars also reveal the presence of so-called fast low-ionization emission regions.
        4,000원
        1180.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We have carried out optical spectroscopic measurements of emission lines for a sample of Galactic plan- etary nebulae with Wolf-Rayet (WR) stars and weak emission-line stars (wels). The plasma diagnostics and elemental abundance analysis have been done using both collisionally excited lines (CELs) and optical recombination lines (ORLs). It was found that the abundance discrepancy factors (ADF = ORL/CEL) are closely correlated with the difference between temperatures derived from forbidden lines and those from He i recombination lines, implying the existence of H-deficient materials embedded in the nebula. The Hβ surface brightness correlations suggest that they might be also related to the nebular evolution.
        3,000원