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        검색결과 436

        82.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Oxygen evolution reaction (OER) is an essential step at an anode in electrochemical water-splitting process and requires efficient electrocatalysts to reduce overpotentials. Although precious metal-based materials, such as RuO2, IrO2 and their hybrids with other components, performed excellently as OER electrocatalysts, their high cost has limited practical applications. Consequently, earth-abundant metal components including Fe, Co, and Ni have been investigated as alternatives. In this work, the hybridization of Ni-containing species with conductive carbon-based materials was used to prevent aggregation of active species and improve electrochemical catalytic performance. A new hybrid material composed of NiO nanoparticles and N-doped carbon materials was prepared. The NiO particles with a narrow size distribution were well dispersed on the surface of carbon-based materials. The hybrid showed improved electrocatalytic performance for OER than single components of NiO and N-doped carbon materials.
        4,000원
        88.
        2020.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Influenza A virus (IAV) causes respiratory disease in birds and mammals, including pigs and humans. Infection by IAV in pigs increases not only economic losses in the swine industry but also the emergence of novel IAV variants via gene reassortment, which is important due to the susceptibility of both birds and humans to IAV. This study provides serological data obtained during a study to detect IAV infections in pigs in the Republic of Korea during 2018 and 2019. A total of 1,559 samples were collected from 74 domestic pig farms. Hemagglutination inhibition (HI) assays were performed using the A/Swine/Korea/25-13(H1N1), A/Swine/Korea/E102 (H1N2), and A/Swine/Korea/Cy10/2007 (H3N2) viruses as antigens. The HI assay results showed that 266 of the 1,559 samples were seropositive (17.0%). Among these, H1N1, H1N2, and H3N2 comprised 7.3% (114), 6.0% (93), and 8.8% (137) of the 1,559 samples, respectively. Co-infections of H1N1/H1N2, H1N1/H3N2, H1N2/H3N2 and H1N1/H1N2/H3N2 were observed in 2.1% (31), 1.5% (23), 1.5% (24), and 0.8% (13) of the 1,559 samples, respectively. Interestingly, IAV infections were detected in all nine provinces of the country.
        3,000원
        89.
        2020.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The Korea Astronomy and Space Science Institute (KASI) has been developing a next-generation coronagraph (NGC) in cooperation with NASA to measure the coronal electron density, temperature, and speed simultaneously, using four different optical filters around 400 nm. KASI organized an expedition to demonstrate the coronagraph measurement scheme and the instrumental technology during the 2017 total solar eclipse (TSE) across the USA. The observation site was in Jackson Hole, Wyoming, USA. We built an eclipse observation system, the Diagnostic Coronal Experiment (DICE), composed of two identical telescopes to improve the signal-to-noise ratio. The observation was conducted at four wavelengths and three linear polarization directions in the limited total eclipse time of about 140 seconds. We successfully obtained polarization data for the corona but we were not able to obtain information on the coronal electron temperature and speed due to the low signal-to-noise ratio of the optical system and strong emission from prominences located at the western limb. In this study, we report the development of DICE and the observation results from the eclipse expedition. TSE observation and analysis with our self-developed instrument showed that a coronagraph needs to be designed carefully to achieve its scientific purpose. We gained valuable experience for future follow-up NASA-KASI joint missions: the Balloon-borne Investigation of the Temperature and Speed of Electrons in the Corona (BITSE) and the COronal Diagnostic EXperiment (CODEX).
        4,300원
        90.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Enterotoxigenic Escherichia coli는 신생 및 이유기 돼지 설사의 주요 원인체로서 전세계적으로 양돈산업에 큰 경제적 손실을 끼치고 있다. 그러나 현재 국내에는 이러한 E. coli가 보유하는 다양한 병원성유전자의 분포 및 특성에 대한 정보가 부족한 실정이다. 이에 본 연구에서는 2013년부터 2016년까지 국내 163개 양돈농장에서 이유기 설사증 개체로부터 면봉스왑 샘플을 채취하여 동일 농장의 개체일 경우 5개에서 10개 정도를 혼합한 후, MacConkey agar에 배양하여 최종 API 32E system을 통하여 동정하였다. 분리된 모든 균주에 대해서 3가지의 다른 multiplex PCR을 수행하여 총 13종의 병원성유전자의 분포를 확인하였다. 이를 통하여 총 172개의 최소 한가지 이상의 병원성 유전자를 가지는 E. coli 균주를 확인하였고, 그 결과 병원성 유전자의 분포는 (1) fimbrial adhesins (43.0%): F4 (16.9%), F5 (4.1%), F6 (1.7%), F18 (21.5%), and F41 (3.5%); (2) toxins (90.1%): LT (19.2%), STa (20.9%), STb (25.6%), Stx2e (15.1%), EAST1 (48.3%); and (3) nonfimbrial adhesin (19.6%): EAE (14.0%), AIDA-1 (11.6%) and PAA (8.7%)로 나타났다. 결론적으로 본 연구결과는 국내 양돈농장의 이유기 설사증에 관연하는 E. coli는 다양한 종류의 병원성 유전자를 가지고 있으며 그러한 병원성 유전자의 조합도 매우 다양하게 분포하고 있음을 나타낸다.
        4,000원
        93.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To understand the genesis of tropical cyclones (TC), we computed TC genesis probability (GPr) by partitioning a highly localized genesis frequency (GFq) into nearby grid boxes in proportion to the spatial coherence of genesis potential index (GPI). From the analysis of TCs simulated by the Seoul National University Atmosphere Model Version 0 and the observed TCs, it was shown that GPr reasonably converges to GFq when averaged over a long-term period in a decent grid size, supporting its validity as a proxy representing a true TC GPr. The composite anomalies of the gridded GPr in association with the Asia summer monsoon, El Nino-Southern Oscillation (ENSO), and the Madden-Julian Oscillation (MJO) are much less noisy than those of GFq, and consequently are better interpretable. In summary, GPr converges to GFq, varies more smoothly than GFq, represents the spatiotemporal variations of GFq better than GPI, and depicts GFq with greater spatial details than other spatially smoothed GFqs.
        4,200원
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