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합성조건의 변화에 따른 액츄에이터 재료로서의 전도성 고분자의 기계적 특성
최영,이승기 ( Young Choi,Seung Ki Lee ) 한국센서학회 1998 센서학회지 Vol.7 No.6
Recently, conductive polymer is known to be direct-drive active material which can convert electrical energy directly into mechanical energy. In this paper, the polymerized thickness of polypyrrole is measured with change of polymerization conditions and the mechanical bending is analyzed for various polymerized thickness. In order to detect of mechanical bending, bending beam method using the bridge shaped sample is used. Thickness of polypyxrole is proportional to polymerization time in fated current density. Also it shows a linear relation with the applied current except high current density. Maximum displacement appears at the thickness of 18.35㎛ which has been polymerized at 5.4 ㎂/㎟ and for 120min and actuated at the frequency of 0.1Hz.
최영임 ( Young Im Choi ),조세경 ( Sei Kyung Cho ) 한국멀티미디어언어교육학회 2015 멀티미디어 언어교육 Vol.18 No.3
This study aims to examine the preferences with regard to multimedia materials displayed by Korean university students, in accordance to the Myers-Briggs Type Indicator (MBTI). MBTI is a psychometric questionnaire designed to evaluate four areas of psychological preferences, including: how people are energized; how people perceive the world; how people make decisions and how people arrive at conclusions. The study focused upon 676 students, for the duration of a fifteen week period while they were attending English classes. The purpose of the study was dual. Firstly, students’ character types were examined via the Myers’ typological personality assessment. Secondly, the correlation between their personality traits and preferences towards certain multimedia materials was investigated. The results of the study indicated that students possessing certain personality characteristics, demonstrated an individual preference relating to specific multimedia material. The study suggested extroverted personality types displayed a preference for off-line activities, therefore limiting the scope of multimedia materials amongst this group of individuals. However, the investigation indicated that students of an introverted disposition preferred online activities, therefore increasing the effect multimedia materials could exhibit upon their English learning. The study also examines the pedagogical implications of the research results and highlights the limitations of the data.
감쇠 구조물에 의한 토석류 토사체적 농도 변화에 관한 실험적 연구
최영도(Youngdo Choi),김성덕(Sungduk Kim),이호진(Hojin Lee) 한국방재안전학회 2023 한국방재안전학회 논문집 Vol.16 No.4
The purpose of this study is an experimental research to investigate the effectiveness of debris flow reduction structures when a debris flow disaster occurs on a steep slope. The control structure for debris flow took the form of baffle, and the soil deposition area and soil runout distance due to debris flow from the downstream were investigated according to the installation number of baffle and each specification. As the slope of the channel became steeper, the sediment deposition area and runout distance increased, and as the sediment volume concentration decreased, the sediment deposition area and runout distance increased. When the sediment concentration was low, differences appeared depending on the slope of the channel because the debris flow had a high liquid content. Overall, the larger the sediment volume concentration, the greater the decrease in sediment deposition area and soil runout distance. As the number of baffles increases, the soil deposition area and runout decrease, showing that the baffles have the ability to control debris flows. The results of this research will provide good information when installing attenuation or control structures when sediment disasters occur in steep slopes. 본 연구의 목적은 급경사지 사면에서 토석류 재해가 발생했을 때, 토석류 저감 구조물의 효과를 조사한 실험연구이다. 제어 구조물로는 베플 형태를 취하였고, 베플의 설치 기수와 각 제원에 따라서 하류에서의 토석류에 의한 토사퇴적면적과 토사도달거리를 조사한 것이다. 수로의 경사가 급할수록 토사의 퇴적면적과 도달거리가 증가하였고, 토사체적농도가 감소할수록 토사퇴적면적과 토사의 도달거리가 증가하였다. 토사농도가 작은 경우(Cv = 0.5)는 토석류의 액성이 크기 때문에 수로 경사에 따른 차이가 나타났고, 전반적으로 토사체적농도가 클수록 토사퇴적면적과 토사의 도달거리 감소율이 크게 나타났다. 베플의 수를 증가할수록 토사퇴적면적과 도달거리를 약 5~10% 이상 감소하는 것으로 나타남으로서 베플의 토석류 제어능력이 있음을 보여주고 있다. 본 연구의 결과는 급경사지에서 토사재해가 발생할 때 감쇠 또는 제어 구조물을 설치할 때 중요한 정보를 제공할 것이다.