• Journal of the Korean Vacuum Society
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• v.2 no.1
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• pp.58-64
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• 1993

이온선혼합의 열충격으로 야기되는 등방저기 또는 이방적 원자이동을 정량적으로 묘사하기 위한 모형을 제시하였다. 불순문 확산에서 원자들의 이동비는 구성원자들의 활성화에너지에 의존한다. 이 모형은 0에 가까운 혼합열과 비교적 높은 활성화에너지를 가진 이중층들의 실험결과들을 만족스럽게 예견한다. 불순물 확산에서 구성원자들의 활성화에너지가 크게 차이가 나는 계들은 이방적 원자이동을 보여주는 반면, 비슷한 활성화에너지를 가지는 계들은 등방적 원자이동을 나타낸다.

• Journal of The Korean Association For Science Education
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• v.31 no.4
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• pp.539-556
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• 2011

The purpose of this study was to examine preservice secondary science teachers' understanding of the nature of science, by using nature of science (NOS) questionnaire on the basis of atomic model, and compare this to pre-studies. 'Understanding of nature of scientific model,' 'Tentativeness of scientific knowledge,' 'Subjectivity in science,' 'Use of inference and imagination,' 'Myths of the scientific method,' and 'Comparison between science and art.' were examined. Preservice teachers showed great comprehension of the tentativeness of scientific knowledge (the orbital model) and the subjectivity in science (the different interpretation about the experiment of particle scattering), but displayed the lowest comprehension of the scientific method. For understanding of nature of scientific model (the atomic model) and the comparison between science (Bohr's atomic model) and art (Picasso's work), preservice teachers brought out a combination of ontological and constructivist perspective and showed the contradictory thought about imagination in science research. In the result of comparison to pre-studies using the NOS instruments contains general terms, represented high levels of agreement about the tentativeness of scientific knowledge by using concrete examples of 'atomic model'. When concrete scientists such as Thomson, Rutherford, Bohr were presented, respondents revealed more informed views about the scientists' research method.

• Journal of the Korean Vacuum Society
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• v.1 no.3
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• pp.341-345
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• 1992

충돌에 의한 원자혼합현상에 대한 해석적모형을 개발하였다. 이 식은 Sigmund와 GrasMarti의 식보다 더 현실적인 이온-원자 충돌변수들을 포함한다. 이 식에 의해서 계산된 경량원소에 대한 혼합효율은 Sigmund 식에 의해서 계산된 것과 동일한 결과를 나타낸다. 반면, 중량원소에 대한 계산은 약간의 차이를 나타낸다. 또 이 결과는 경량원소에 대한 dynamic Monte-Carlo 모의실험결과와 잘 일치하고 있는 반면, 중량원소에 대해서는 약간 의 차이를 나타내는데, 이는 이온 조사시의 sputtering과 기지원자 재배치에 기인한 것으로 추측된다.

• Journal of the Korean Chemical Society
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• v.47 no.3
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• pp.273-282
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• 2003

A questionnaire on "atomic models and electron configuration" was performed on 34 of 11th grade and 38 of 12th grade students who took the Chemistry-II course in order to examine the degree of learning achievement. Also eight Chemistry-II textbooks published in the 6th curriculum were analyzed for the similarities and differences in dealing with this topic and possible improvements were discussed in conjunction with the questionnaire. The results of this questionnaire showed that the degree of learning achievement on the topics between two different classes were not much different in general, although a little difference was found. This indicates that the topics have been taught in early 11th grade but subsequent supplemental teaching has not been performed. To study on the topics of "atomic models and electron configuration" effectively and systematically, knowledge on the basic spectroscopy and quantum mechanics should be preceeded. However this could be practically difficult under the current high school curriculum. Therefore It would be necessary to describe the basic concepts for the quantum mechanics and spectroscopy schematically in the "Reference Materials" section of the textbook, even if it is not very long. On the other hand, the Chemistry-II textbooks analyzed in this work reveal, in general, to have the similar organization and explanation modes. However it has been analyzed that a connection between the Bohr and electron-cloud atomic models might be insufficient or position of electrons might be possible to be misunderstood by students in some textbooks.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.118.2-118
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• 2001

• Journal of Science Education
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• v.39 no.1
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• pp.15-27
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• 2015

This study investigated whether there was a difference of the change in perspective of the nature of science depending on subjects of the history of science, after designing for two kinds of topics of role play programs based on the history of science to be transformed into a modern perspective. Before the history of science-role plays, the degree of the modern perspective was statistically no difference between group I(the atomic model transition-role play) and group II(the Mendeleev's periodic table-role play). However after treatment of the history of science-role plays for the each group, the degree of group I was higher than the degree of group II in the modern perspective. The results of this study indicate that the degree of changes into modern perspective of the nature of science by performing a history of science-role play may be depend on the subject of the history of science combined with the role play, and suggest the possibility that may be more effective to change the nature of science into the modern perspective, in case of performing of role play based on the history of science that includes the scientific knowledge established by a number of scientists with time series.

• Journal of the Korean Data and Information Science Society
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• v.24 no.3
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• pp.533-541
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• 2013

In this study, a simple principal component analysis using Lasso is proposed. This method consists of two steps. The first step is to compute principal components by the principal component analysis. The second step is to regress each principal component on the original data matrix by Lasso regression method. Each of new principal components is computed as the linear combination of original data matrix using the scaled estimated Lasso regression coefficient as the coefficients of the combination. This method leads to easily interpretable principal components with more 0 coefficients by the properties of Lasso regression models. This is because the estimator of the regression of each principal component on the original data matrix is the corresponding eigenvector. This method is applied to real and simulated data sets with the help of an R package for Lasso regression and its usefulness is demonstrated.

• The Korean Journal of Applied Statistics
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• v.34 no.1
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• pp.75-98
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• 2021

This paper compares three statistical models that examine the relationship between national and provincespecific fertility rates. The three models are two of the regression models and a cointegration model. The regression model is by substituting Gompit transformation for the cumulative fertility rate by the average for ten years, and this model applies the raw data without transformation of the fertility data. A cointegration model can be considered when fitting the unstable time series of fertility rate in probability process. This paper proposes the following when it is intended to derive the relation of non-stationary fertility rate between the national and provinces. The cointegrated relationship between national and regional fertility rates is first derived. Furthermore, if this relationship is not significant, it is proposed to look at the national and regional fertility rate relationships with a regression model approach using raw data without transformation. Also, the regression model method of substituting Gompit transformation data resulted in an overestimation of fertility rates compared to other methods. Finally, Seoul, Busan, Daegu, Incheon, Gwangju, Daejeon and Gyeonggi province are expected to show a total fertility rate of 1.0 or less from 2025 to 2030, so an urgent and efficient policy to raise this level is needed.

• Journal of computational fluids engineering
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• v.3 no.1
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• pp.89-99
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• 1998

한국형 차세대원자로에서는 비상노심 안전주입수가 저온관을 통하지 않고 원자로용기에 직접 주입된다. 원자로용기의 가압열충격과 열수력적 관점에서 최적의 노즐위치를 결정하기 위해서 전산유체역학을 활용하였다. 상용 전산유체코드인 CFX를 이용하여 원자로 하향유로를 모사하는 해석대상 격자를 다중불록으로 형성한 다음 유동장을 비압축성 Navier-Stokes 운동량 방정식, 에너지 방정식과 표준 k-ε 난류모형 등으로 모형화하여 3차원 비정상상태 계산을 수행하였다. CFX에서는 경계 밀착좌표계, 비엇물림격자와 SIMPLE 알고리즘을 사용한다. 본 연구결과 원자로용기의 가압열충격 관점에서 가장 보수적인 사고인 증기관 파단사고시에도 열적혼합이 잘 일어나 가압열충격이 발생할 가능성이 없는 것으로 판단되며 안전주입수 노즐이 저온관 바로 위에 위치할 때 원자로 하향유로 내의 온도 분포가 가장 균일하여 열적 혼합 관점에서는 최적의 위치로 판단된다.

• Nuclear industry
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• v.16 no.5 s.159
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• pp.59-68
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• 1996

한국원자력연구소는 최근 원자력 선진국인 프랑스로부터 원자로 격납 용기 실험 용역 사업을 국내 최초로 수주, 그동안 꾸준히 수행해 온 중대 사고에 대한 원전 안전성 확보를 위한 연구 성과를 국외에서 인정받게 되었다. 본 실험의 목적은 프랑스 900MWe 표준 원전 캐비티 모형에 대한 중대 사고시 고압 방출에 의해 캐비티 밖으로 방출되는 용융 노심 파편물의 방출량을 측정하고, 방출분율을 예측하는 상관식의 검증과 캐비티의 구조 특성을 고려할 수 있는 상관식을 개발하는 것으로서, 금년 2월부터 내년 1월까지 수행한다.