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        검색결과 19

        2.
        2024.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study explores the development of professionalism in using Educational Technology (EdTech) among Korean elementary English teachers amid the increasing integration of technology in English education. Employing the Grounded Theory methodology, the study involved in-depth interviews with nine Korean elementary English teachers experienced in using EdTech. It aims to identify their EdTech experiences, the elements constituting EdTech professionalism, and its developmental process. The study reveals that teachers’ EdTech professionalism encompasses a proactive approach towards technology, continuous professional growth based on practice and reflection, and adaptation of teaching methods in response to evolving technologies and learner needs. It highlights the importance of teachers’ self-directed approach, collaboration with other teachers, and the integration of pedagogical, content, and technological knowledge into their English teaching. The findings have implications for teacher education and the advancement of EdTech-utilized English education, suggesting new processes and directions for developing elementary English teachers’ professionalism in the rapidly evolving landscape of educational technology.
        6,700원
        3.
        2023.11 구독 인증기관·개인회원 무료
        This study demonstrated a rapid and simple method for the determination of seven anions including halides and oxyhalides from the KURT underground water sample by capillary electrophoresis with UV detection. In nuclear waste disposal, some anions such as iodine, selenium, and technetium have been of great concern due to its high mobility and toxicity with a long half-life. It has been needed for a reliable analysis of anionic speciation because the high mobility of anions is easily affected by environmental conditions especially pH and salinity of underground water. Here this project is to develop a fast separation of seven anions including iodide, iodate, and selenite using capillary electrophoresis. The electroosmotic flow (EOF) was suppressed using a poly (ethyleneglycol) -coated capillary (DB-WAX capillary). As a result, anions migrated depending on their mobility under a reverse polarity condition (-15 kV) and the analysis time was within 15 min. UV detection was used at 200 nm. The RSDs for migration time were between 0.7% and 1.3% except for selenite of 5.1%. The RSDs for peak area were obtained between 2.9% and 7.4%. The calibration curves were linear from 10 to 200 mg/L with correlation coefficients greater than 0.9952. The LODs were 7.3, 10.9, 11.3, 12.9, 13.0, 13.9, and 17.4 mg/L for iodide, nitrate, bromide, selenite, bromate, tungstate and iodate. The KURT underground water sample spiked with seven anions at 50 mg/L were analyzed. The recoveries of spiked KURT sample ranged from 93.4% to 99.3%. The proposed method was successfully applied to determine seven anions in underground water sample.
        8.
        2020.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Silicon heterojunction solar cells can achieve high conversion efficiency with a simple structure. In this study, we investigate the passivation characteristics of VOx thin films as a hole-selective contact layer using ALD (atomic layer deposition). Passivation characteristics improve with iVoc (implied open-circuit voltage) of 662 mV and minority carrier lifetime of 73.9 μs after post-deposition annealing (PDA) at 100 oC. The improved values are mainly attributed to a decrease in carbon during the VOx thin film process after PDA. However, once it is annealed at temperatures above 250 oC the properties are rapidly degraded. X-ray photoelectron spectroscopy is used to analyze the chemical states of the VOx thin film. As the annealing temperature increases, it shows more formation of SiOx at the interface increases. The ratio of V5+ to V4+, which is the oxidation states of vanadium oxide thin films, are 6:4 for both as-deposition and annealing at 100 oC, and 5:5 for annealing at 300 oC. The lower the carbon content of the ALD VOx film and the higher the V5+ ratio, the better the passivation characteristics.
        4,000원
        9.
        2020.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        원전 해체 공정 중 다량의 콘크리트 방사성 폐기물의 절단 과정에서 불가피하게 방사성 에어로졸이 생성된다. 방사성 에어 로졸은 인체 호흡기 흡착에 의한 내부피폭을 유발하기 때문에 작업자의 방사선 방호를 위한 내부피폭평가가 필수적으로 시행되어야 한다. 그러나 실제 작업환경의 에어로졸 특성값을 사용하기에는 선행 연구가 미비하며 콘크리트에 포함된 방사성 핵종의 수가 많기 때문에 정확한 작업자 내부피폭평가를 위해서는 상당한 시간과 인력이 필요하다. 따라서, 본 연구에서는 사전 연구된 콘크리트 에어로졸 특성값을 활용하여 원전 해체 전 절단 작업자의 내부 피폭량을 빠르게 예측할 수 있는 새로운 방법론을 제시하고자 한다. 본 연구팀은 콘크리트 절단 시 발생하는 사전 연구에서 발표된 에어로졸의 수농도 크기 분포데이터를 뉴턴-랩슨법을 이용하여 피폭평가 계산에 필요한 방사능중앙 공기중역학직경(Activity Median Aerodynamic Diameter)값으로 변환하였다. 또한 원전 정지 10년 후 비방사능 값을 ORIGEN code로 계산하였으며, 최종적으로 핵종별 예 탁유효선량을 IMBA 프로그램을 이용하여 계산하였다. 핵종별 예탁유효선량값을 비교한 결과 152Eu에 의한 최대 예탁유효선량은 전체 선량값의 83.09%를 차지하고, 152Eu를 포함한 상위 5개 원소(152Eu, 154Eu, 60Co, 239Pu, 55Fe)의 경우 최대 99.63%를 차지함을 확인하였다. 따라서 원전 해체 전 콘크리트의 구성 원소 중 상위 5개 주요 원소 측정을 먼저 시행한다면 더 빠르고 원활한 방사능 피폭관리 및 해체 작업 안전성 평가가 가능할 것으로 판단된다.
        4,200원
        10.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        선충포식성 곰팡이는 선충을 포획하기 위하여 다양하고 특수한 기관을 사용한다. 국내 성주지역의 참외 경작지 뿌리 주변의 토양에서 3차원 접착 고리를 형성하여 선충을 포획하는 곰팡이를 분리하였다. 곰팡이의 미세형태 구조를 관찰한 결과 분생포자병은 직립형으로 길이는 290~528 (342.8) μm으로 길었으며, 계란형의 30.5 × 20.3 μm 크기를 가진 1~3개의 분생포자를 형성하였다. 균주의 rDNA의 5.8 S 영역의 염기서열을 분석한 결과, Arthrobotrys속의 계통군에 속하였으며, 특히 Arthrobotrys sinensis와 99%의 유사성을 보였다. 형태적 특징과 분자생물학적 계통 분석을 바탕으로 본 균주는 A. sinensis로 확인되었으며, 이는 국내 미기록종으로 식물기생성선충의 생물학적 조절을 위한 하나의 자원이 될 수 있다.
        4,000원
        13.
        2016.04 구독 인증기관·개인회원 무료
        To select resistant oil seed crops against two species of root-knot nematodes, M. incognita and M. arenaria, 10 cultivars of sesame (Sesamum indicum) and 10 cultivars of perilla (Perilla frutescens var. japonica) were screened in greenhouse pot test. All sesame cultivars tested were resistant to M. incognita but susceptible to M. arenaria. While, perilla was resistant to both Meloidogyne species. Therefore, perilla cultivars could be used as rotation crops in greenhouses infested with both M. incognita and M. arenaria. But, sesame cultivars only can be used as a rotation crops in greenhouses infested with M. incognita but not for M. arenaria.
        14.
        2014.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We develop a parallel cosmological hydrodynamic simulation code designed for the study of formation and evolution of cosmological structures. The gravitational force is calculated using the TreePM method and the hydrodynamics is implemented based on the smoothed particle hydrodynamics. The ini- tial displacement and velocity of simulation particles are calculated according to second-order Lagrangian perturbation theory using the power spectra of dark matter and baryonic matter. The initial background temperature is given by Recfast and the temperature uctuations at the initial particle position are as- signed according to the adiabatic model. We use a time-limiter scheme over the individual time steps to capture shock-fronts and to ease the time-step tension between the shock and preshock particles. We also include the astrophysical gas processes of radiative heating/cooling, star formation, metal enrichment, and supernova feedback. We test the code in several standard cases such as one-dimensional Riemann problems, Kelvin-Helmholtz, and Sedov blast wave instability. Star formation on the galactic disk is investigated to check whether the Schmidt-Kennicutt relation is properly recovered. We also study global star formation history at different simulation resolutions and compare them with observations.
        4,300원