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호흡 실험에서 고등학생의 인지 갈등 불안 유형에 따른 설명 가설 생성의 변화
권영식,이길재 韓國生物敎育學會 2009 생물교육 Vol.37 No.2
The purpose of this study is to investigate the students' cognitive conflict anxiety types, differences of explanatory hypotheses and the changes of anxiety type after test experiment in respiration experiment. Results showed that high anxiety types were divided into conviction in logical misconception, insisting on additional variables, lack of confidence and conflict with past experience, whereas low anxiety types were divided as only reasonable modification in this study. Also, the results showed that there were differences in explanatory hypotheses after test experiment according to anxiety type of cognitive conflict. Moreover, these anxiety types were variously changed after test experiment. Especially, students that their anxiety type was changed into reasonable modification showed higher variation of explanatory hypothesis. Therefore, It was concluded that teaching strategy in terms of cognitive conflict should be focused on facilitating students' ability to change their anxiety type into reasonable modification.
혼합 정수 비선형모형에 의한 발전 시스템의 단기운영계획의 수립
권영식,김철수 동국대학교 산업기술대학원 1993 산업기술논문집 Vol.1 No.-
For the short term power scheduling, a mixed integer nonlinear model and Lagrangian relaxation algoritm are proposed. The proposed model considers ramping rate, mixed-limited fuel units and operational status, in addition to the factors considered in the previous studies. The computational experiences show the heuristic algorithm can solve the problem within reasonable interations, resulting in acceptable duality gaps.
균일입도 초미분 $Y(OH)CO_3 \cdot $nH_2O$ 생성에 미치는 요소 농도의 영향
권영식,김동수,Kwon, Young Shik,Kim, Dong Su 대한화학회 1998 대한화학회지 Vol.42 No.2
Homogeneous precipitation of $Y^{3+}$ with urea has been studied in order to investigate the effect of urea concentration on the preparation of monodispersed colloidal "Yttrium Hydroxycarbonate $(Y(OH)CO_3 \cdot nH_2O)$". As the initial concentration of urea increased, the mean size of colloidal precipitates decreased, and the rate of precipitation of $Y^{3+}$ increased. When the initial concentration of urea was higher than $4.0 \sim 7.0 M$, precipitates obtained were no more monodispersed colloidal particles, but coagulated big particles; and, although the initial concentration of urea increased over 4.0 M, the rate of precipitation did not increased. It is important to decide the proper initial concentration of urea, because excessive urea can cause the environmental problems such as water pollution. 균일 침전법에서 침전제인 요소의 초기 농도가, 생성되는 균일 입도 초미분 $Y(OH)CO_3 \cdot nH_2O$침전의 형상, 입도 및 침전 속도 등에 미치는 영향을 조사하였다. 요소의 초기 농도가 높을수록 얻어지는 균일 입도 초미분의 평균 입도는 작아지나, 일정농도(본 실험조건의 경우 4.0~7.0M사이) 이상으로 높아지면 급격한 침전 반응으로 인해 불규칙한 형상의 응집된 큰 침전이 얻어졌다. 요소의 초기농도가 증가함에 따라 침전 반응속도는 증가하나, 일정농도(본 실험 조건의 경우, 약 4.0M)이상이 되면, 요소 농도 증가에 따른 반응 속도의 증가가 더 이상 없는 포화 상태가 되었다. 요소의 과잉 사용은 반응후 남는 미분해 요소의 증가로 인해 수질 오염 등의 환경 문제를 유발시키므로, 얻고자 하는 침전 크기 및 반응 속도 등을 고려하여 적정한 요소의 초기 농도를 결정하는 것은 공업적 및 환경적 측면에서 중요하다고 판단된다.