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        검색결과 216

        64.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Korea Astronomy and Space Science Institute plans to develop a coronagraph in collaboration with National Aeronautics and Space Administration (NASA) and to install it on the International Space Station (ISS). The coronagraph is an externally occulted one-stage coronagraph with a field of view from 3 to 15 solar radii. The observation wavelength is approximately 400~nm, where strong Fraunhofer absorption lines from the photosphere experience thermal broadening and Doppler shift through scattering by coronal electrons. Photometric filter observations around this band enable the estimation of 2D electron temperature and electron velocity distribution in the corona. Together with a high time cadence ($<$12~min) of corona images used to determine the geometric and kinematic parameters of coronal mass ejections, the coronagraph will yield the spatial distribution of electron density by measuring the polarized brightness. For the purpose of technical demonstration, we intend to observe the total solar eclipse in August 2017 with the filter system and to perform a stratospheric balloon experiment in 2019 with the engineering model of the coronagraph. The coronagraph is planned to be installed on the ISS in 2021 for addressing a number of questions (e.g., coronal heating and solar wind acceleration) that are both fundamental and practically important in the physics of the solar corona and of the heliosphere.
        4,200원
        67.
        2017.10 구독 인증기관·개인회원 무료
        Orius minutus (L.) (Hemiptera: Anthocoridae) is a native predators of soft body insects such as mites, thrips, and aphids.We compared 24 h consumption rate of O. minutus with that of a commercialized O. laevigatus (Fieber) on egg andadult stage of Tetranychus urticae Koch (Acari: Tetranychidae). Orius minutus predated 1.4 times more adult T. urticae(58 mites) in 24 h than O. laevigatus. Similarly, O. minutus consumed 128 eggs while O. laevigatus consumed 98 eggsin 24 h without statistical difference. These results suggest that native O. minutus can be applied for the augmentativebiological control after the development of mass-rearing method.
        68.
        2017.10 구독 인증기관·개인회원 무료
        Through an integration of seasonal climate forecasts (SCF) and rice pest epidemiological models, a potential risk forrice pest epidemics can be predicted even before a cropping season starts. The objective of the study was to developand evaluate an epidemiological “rtdSim” model for tungro, a vector-born rice disease, aiming at predicting a seasonaltungro risk in the Bicol Region of the Philippines. Predicting tungro epidemics requires many components explaining thecomplex nature of the three-cornered pathosystems (virus, vector, and host) and their interactions with environmental variables.The rtdSim model successfully calculated number of rice hills infected with the rice tungro virus through its vector, thegreen leafhopper (GLH). The present study highlights the potential for developing a climate-based early warning systemfor rice pests, thus allowing better decision-making on a seasonal level.
        70.
        2017.06 구독 인증기관 무료, 개인회원 유료
        Effective estrus detection and artificial insemination (AI) are necessary for profitable management of dairy herd. In current study, 45 crossbred lactating cows have been selected with the complaint of unobserved oestrus for more than sixty days postpartum. All cows had functional corpus luteum as examined by transrectal ultrasonography. Cows were treated with PGF2α analogue and AI was performed with observed oestrus and then single dose of GnRH was administered. Similar synchronization protocol has been repeated after 14 days in cows that did not repose to first treatment. Remaining cows received additional PGF2α after 14 days of second treatment and timed AI was performed following GnRH administration. Among 45 cows, 28.89% showed estrus after first treatment and 78.79% responded to second hormonal intervention. A higher conception rate (88.89% vs 26.66 and 72.72%) was observed in cows after triple administration of PGF2α and timed AI. We noticed a significant differences in body condition score (BCS, 1~5 scale), postpartum period, and daily milk production between cows that either responded of non-responded following first and second hormonal treatment. In addition, there was a significant positive correlation between daily milk production and BCS, age and postpartum days, milk production and estrus/BCS, and milk production/BCS/estrus and conception rate. Depending upon the findings we conclude that hormonal intervention with PGF2α and GnRH enhances postpartum ovarian cyclicity and help decreasing the days open of dairy herd. Therefore, this finding might provide an excellent guideline for target breeding system for profitable dairy herd management.
        4,000원
        71.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        How does the presence of an AGN in uence the total SFR estimates of galaxies and change their distribution with respect to the Galaxy Main Sequence? To contribute to solving this question, we study a sample of 1133 sources detected in the North Ecliptic Pole field (NEP) by AKARI and Herschel. We create a multi-wavelength dataset for these galaxies and we fit their multi-wavelength Spectral Energy Distribution (SED) using the whole spectral regime (from 0.1 to 500 μm). We perform the fit using three procedures: LePhare and two optimised codes for identifying AGN tracers from the SED analysis. In this work we present an overview of the comparison between the estimates of the Infrared bolometric luminosi- ties (between 8 and 1000 μm) and the AGN fractions obtained exploiting these di erent procedures. In particular, by estimating the AGN contribution in four different wavelength ranges (5-40 μm, 10-20 μm, 20-40 μm and 8-1000 μm) we show how the presence of an AGN affects the PAH emission by suppressing the ratio L8 μm L4:5 μm as a function of the considered wavelength range.
        4,000원
        72.
        2017.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The thermoelectric Seebeck and Peltier effects of a single walled carbon nanotube (SWCNT) quantum dot nanodevice are investigated, taking into consideration a certain value of applied tensile strain and induced ac-field with frequency in the terahertz (THz) range. This device is modeled as a SWCNT quantum dot connected to metallic leads. These two metallic leads operate as a source and a drain. In this three-terminal device, the conducting substance is the gate electrode. Another metallic gate is used to govern the electrostatics and the switching of the carbon nanotube channel. The substances at the carbon nanotube quantum dot/ metal contact are controlled by the back gate. Results show that both the Seebeck and Peltier coefficients have random oscillation as a function of gate voltage in the Coulomb blockade regime for all types of SWCNT quantum dots. Also, the values of both the Seebeck and Peltier coefficients are enhanced, mainly due to the induced tensile strain. Results show that the three types of SWCNT quantum dot are good thermoelectric nanodevices for energy harvesting (Seebeck effect) and good coolers for nanoelectronic devices (Peltier effect).
        4,000원
        73.
        2016.10 구독 인증기관 무료, 개인회원 유료
        In recent years there has been a drop in the percentage of male teachers. The gender disparity is evidenced in many primary and secondary schools in Nigeria. This article is set to ascertain the nature of gender disparity in Nigerian publicly funded schools, the underlying reasons for the growing disparity, such as the feminization of the teaching profession, low teacher’s salary, flexibility of teaching of the profession, women as care givers, cultural belief, and sexual molestation. Challenges to the increase of male teachers in schools, such as low status of teaching, parental expectation, work policies and societal perception were explored. The implications of the absence of male teachers in the schools, among others, were failure among male students, academic under-achievement, under-utilization of male talent and indiscipline in school. Suggested courses for action to increase the presence of male teachers in schools include improving the condition of service, education policy reform, gender balance in other professions, publicizing a male friendly environment, and admitting men to educational programs. The aforementioned are efforts meant to encourage diversity in the teaching workforce. The article relied heavily on data collected from Education Management Boards of some Nigerian States’ for its discussion.
        6,100원
        76.
        2016.03 구독 인증기관 무료, 개인회원 유료
        Coastal areas across the globe and people who live in them are vulnerable to a host of natural disasters including hurricanes, typhoons, and tsunamis. During the past several decades, coastal communities of the world have also been seriously affected by man-made disasters resulting in severe social, economic, and environmental damages. The 2010 Deepwater Horizon oil spill (DWH) was the worst man-made disaster for the Gulf coast communities of the US. Community residents and resource organizations in the Florida Gulf coast responded quickly to address social, economic, and environmental needs after this disaster. The purpose of this single case study is to determine these community responses. The research uses documents from community organizations and in-depth interviews with community leaders. Constant comparative analysis method was used to determine major and sub categories of community efforts. Results show that community efforts centered on collaboration, outreach, and grassroots mobilization for resiliency after the disaster.
        4,000원
        78.
        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
        79.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We first deduce a uniform formula forthe Fermi energy of degenerate and relativistic electrons in the weak-magnetic field approximation. Then we obtain an expression of the special solution for the electron Fermi energy through this formula, and express the electron Fermi energy as a function of electron fraction and matter density. Our method is universally suitable for relativistic electron- matter regions in neutron stars in the weak-magnetic field approximation.
        3,000원
        80.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Eclipsing Binaries Minima (BIMA) Monitoring Project is a CCD-based photometric observational program initiated by Bosscha Observatory - Lembang, Indonesia in June 2012. Since December 2012 the National Astronomical Research Institute of Thailand (NARIT) has joined the BIMA Project as the main partner. This project aims to build an open-database of eclipsing binary minima and to establish the orbital period of each system and its variations. The project is conducted on the basis of multisite monitoring observations of eclipsing binaries with magnitudes less than 19 mag. Di erential photometry methods have been applied throughout the observations. Data reduction was performed using IRAF. The observations were carried out in BVRI bands using three di erent small telescopes situated in Indonesia, Thailand, and Chile. Computer programs have been developed for calculating the time of minima. To date, more than 140 eclipsing binaries have been observed. From them 71 minima have been determined. We present and discuss the O-C diagrams for some eclipsing binary systems.
        4,000원
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