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정남미(Chung Nam Mi) 한국열린유아교육학회 2002 열린유아교육연구 Vol.7 No.2
본 연구는 쓰기발달과정을 역사적 수준과 개인적 수준에서 고찰한 것이다. 이를 위해 인간의 쓰기역사와 유아의 쓰기발달과정에서의 전반적인 발달경향과 특징, 공통점과 차이점, 변화의 메카니즘을 분석하고, 발달과정을 비교 분석하였다. 쓰기발달과정은 새로운 형태의 출현과 사라짐, 진보, 퇴화, 변형을 겪으며 단일한 직선적 발달경로를 따르지 않기 때문에 분석에 어려움이 따른다. 그러나 본 연구결과에 따르면 두 발달현상은 그리기에서 표준쓰기에 이르기까지 철자법의 원리에 대한 이해를 향해 나아가는 공통점과 몇가지 차이점을 지니며, 정확한 1:1 대응식 반복은 아니지만 상호 연관성이 있는 것으로 분석되었다. This study was to understand young children's writing development ar the historical as well as the individual level. The literature on this subject and case study were used to investigate the connectedness between the history of writing and the development of writing in the young child. As a result of the analysis, there were some common elements and some discrepancies between the two phenomena and they could compare correspondingly. The history of orthography as well as children's developing knowledge of writing revealed that both phenomena in general proceeded toward an understanding of the writing principle from pictures to letters. However, the order in which the knowledge and discovery occurred in the child as well as just what knowledge became understood during the progression toward the conventional writing model did nor follow a strict one-to-one recapitulation model or explanation. For the in-depth understanding and teaching of writing, it is important to grasp the similarity and difference at the historical as well as the individual level. At a glance, drawing and writing have no common features. But it is revealed that drawing precede writing and play an essential part as a scaffold for writing development in the two phenomena.
Boundary element analysis of stress singularity in dissimilar metals by friction welding
정남용,C.-H. Park 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.9
Friction-welded dissimilar metals are widely applied in automobiles, rolling stocks, machine tools, and various engineering fields. Dissimilar metals have several advantages over homogeneous metals, including high strength, material property, fatigue endurance, impact absorption, high reliability, and vibration reduction. Due to the increased use of these metals, understanding their behavior under stress conditions is necessary, especially the analysis of stress singularity on the interface of friction-welded dissimilar metals. To establish a strength evaluation method and a fracture criterion, it is necessary to analyze stress singularity on the interface of dissimilar metals with welded flashes by friction welding under various loads and temperature conditions. In this paper, a method analyzing stress singularity for the specimens with and without flashes set in friction-welded dissimilar metals is introduced using the boundary element method. The stress singularity index (λ ) and the stress singularity factor ( Γ ) at the interface edge are computed from the stress analysis results. The shape and flash thickness, interface length, residual stress, and load are considered in the computation. Based on these results, the variations of interface length (c) and the ratio of flash thickness (2 1t t ) greatly influence the stress singularity factors at the interface edge of friction-welded dissimilar metals. The stress singularity factors will be a useful fracture parameter that considers stress singularity on the interface of dissimilar metals.
초음파 탐상법을 이용한 접착이음에 대한 계면 균열의 검출
정남용,박성일,이명대,Jeong, Nam-Yong,Park, Seong-Il,Lee, Myeong-Dae 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.3
In is well recognized that the ultrasonic method is one of the most common and reliable nondestructive testing(NDT) methods for the quantitative estimation of defects in welded structures. However, NDT techniques applying for adhesively bonded joints have not been clearly established yet. In this paper, the detection of interface crack by the ultrasonic method was applied for the measurement of interface crack length in the adhesively bonded joints of double-cantilever beam(DCB). The optimum condition of transmission coefficients and experimental accuracy by the ultrasonic method in the adhesively bonded joints have been investigated. The experimental values are in good agreement with the computed results by boundary element method(BEM) and Riplings equation.
농촌 디베이트 교육이 농업농촌 가치 인식에 미치는 영향- 청소년을 대상으로 -
정남식,최은희,김용근 한국농촌계획학회 2019 농촌계획 Vol.25 No.3
The purpose of this study is to investigate the value perception changes of early adolescents, who are from 5th grades to 7th grades regarding to agriculture and rural communities through debate education. Since current education policy to educate agricultural value is limited in solving stereotypes and acquiring abundant relevant knowledge about agricultural values, this study tried to test the effect of debate education for the change of value perception of early adolescents about agriculture and rural communities. Through the two weeks of a debate education course, the differences of perception changes between the experimental group and control group were analyzed. As a result, education on agriculture and rural communities through debate has a great influence on the change of value perception and thus, it could be used as a supplementary educational method for literacy education and field trip learning. Lastly, limitations and implications for the study is discussed.
Al/ Epoxy 이종 접합체에 대한 계면강도의 평가방법
정남용,Chung, Nam-Yong 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.11
The application of bonded dissimilar materials to industries as automobiles, aircraft, rolling stocks, electronic devices and engineering structures is increasing gradually because these materials, compared to the homogeneous materials, have many advantages for material properties. In spite of such wide applications of bonded dissimilar materials, the evaluation method of quantitative strength considering the stress singularities for its bonded interface has not been established clearly. In this paper, the stress singularity for Bctors and the stress intensity factors were analyzed by boundary element method(BEM) for the scarf joints of Al/Epoxy with and without a crack, respectively. From static fracture experiments of the bonded scarf joints, a fracture criterion and a evaluation method of interface strength in bonded dissimilar materials were proposed and discussed.