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초고온 소재용 ZrB<sub>2</sub>계 복합소재의 제조
김성원,채정민,이성민,오윤석,김형태,남산,Kim, Seong-Won,Chae, Jung-Min,Lee, Sung-Min,Oh, Yoon-Suk,Kim, Hyung-Tae,Nahm, Sahn 한국분말야금학회 2009 한국분말재료학회지 (KPMI) Vol.16 No.6
$ZrB_2$-based composites are candidate materials for ultra-high temperature materials (UHTMs). $ZrB_2$ has become an indispensable ingredient in UHTMs, due to its high melting temperature, relatively low density, and excellent resistance to thermal shock or oxidation. $ZrB_2$ powders are usually synthesized by solid state reactions such as carbothermal, borothermal, or combined carbothermal reaction. SiC is added to this system in order to enhance the oxidation resistance of $ZrB_2$. In this study, $ZrB_2$?based composites were successfully synthesized and densified through two different processing paths. $ZrB_2$ or $ZrB_2$ 25 vol.%SiC was fully synthesized from oxide starting materials with reducing agents after heat treatment at 1400$^{\circ}C$. Besides, $ZrB_2$?20 vol.%SiC was fully densified with $B_4C$ as a sintering additive after hot pressing at 1900$^{\circ}C$. The synthesis mechanism and the effect of sintering additives on densification of $ZrB_2$ ?SiC composites were also discussed.
수업 지도안 분석을 통한 예비 교사의 수업 전문성 변화
김성원(Seong-Won Kim),이소율(Soyul Yi),이영준(Youngjun Lee) 한국컴퓨터정보학회 2020 韓國컴퓨터情報學會論文誌 Vol.25 No.1
본 연구에서는 TPACK 교육을 통해 예비 교사의 수업 전문성 변화를 분석하였다. 이러한 연구를 위하여 예비 교사 20명을 대상으로 김성원과 이영준(2019)에서 개발한 프로그래밍 기반 TPACK 교육 프로그램을 적용하였다. 수업 전문성 분석을 위하여 예비 교사가 작성한 수업 지도안을 분석 틀을 활용하여 분석하였다. 연구 결과, 1차 수업 지도안에서 예비 교사는 테크놀로지 활용이 저조하며, 지식을 전달하거나 실험하는 수업을 설계하였다. 2차 수업 지도안에서는 테크놀로지 활용이 증가하였지만, 교육적 맥락에 따라 테크놀로지가 활용되지 않았다. 3차 수업 지도안에서 모든 예비 교사가 테크놀로지를 교육적 맥락에 따라 활용하는 것을 확인할 수 있었다. 또한, 예비 교사의 수업 전문성은 통계적으로 유의한 향상이 나타났다. This study analyzed the change of teaching expertise of pre-service teachers through TPACK education. In this study, we applied a programming-based TPACK education program developed by Kim and Lee (2019) to 20 prospective teachers. To analyze the pre-service teachers’ teaching expertise analyzed the lesson plan prepared before, during and after applying the educational program. As a result, Few teachers use technology in lesson plan, and the design of the instructor-led or experiment to confirmed content in curriculum or textbook. The use of technology has increased in the second Teaching Plan, but the technology was not used depending on the educational context. In the third lesson plan, all pre-service teachers were able to use technology in an educational context. Moreover, the teaching expertise of the pre-service teacher showed a statistically significant improvement in the lesson plan. This study founded that the programming-based TPACK education program was effective in enhancing the teaching expertise of the pre-service teacher.
한국(韓國)의 전자정부(電子政府)와 거버넌스 향상 방안
김성원,김종성,Kim, Sung-Won,Kim, Jong-Seong 한국과학기술정보연구원 과학기술정보센터 2012 Journal of Information Science Theory and Practice Vol.43 No.3
한국의 전자정부 구축 현황을 살펴보고 전자정부를 통하여 거버넌스의 향상에 기여할 수 있는 방안에 대해 고찰해 보았다. 한국의 전자정부는 구현 수준에 있어 국제적 평가에서 상위권에 위치하는 것을 확인할 수 있었으나 전자정부 발전의 최종단계인 통합처리의 관점에서는 지속적인 개선 노력이 필요한 상황으로 평가되었다. 한국의 전자정부가 거버넌스의 향상에 어느 정도 기여하고 있는가를 평가하기 위해 공급자와 이용자의 관점에서 전자정부의 활용도를 평가하였으며 거버넌스와 관련된 기능의 제공 및 활용이라는 정성적인 관점에서 활용도를 평가해 보았다. 한국의 전자정부 활용도는 정량적인 관점에서 상당한 수준에 도달해 있으나 거버넌스의 향상에 기여할 수 있는 이용목적이라는 정성적인 관점에서는 여전히 개선의 여지가 있는 것으로 평가되었다. 위와 같은 평가에 기반하여 전자정부를 통한 거버넌스 향상을 위해 필요한 고려사항들을 제시하였다. This study examines the status of Korean E-government implementation and explores the ways to contribute to governance improvement by means of the e-government. As far as the level of implementation of e-government, Korea is confirmed to have achieved upper level by global standards, but it is found that continuous efforts of improvement is still required in the area of integrative management, which is considered as a final phase of e-government development. In order to evaluate how much e-government of Korea has contributed to the improvement of governance, I tried to measure the usability of e-government from the perspective of providers and that of consumers, and also, a qualitative evaluation on the provision and usage of functions related to the governance was also adopted. It is concluded that, while Korean e-government has reached a remarkable stage in the quantitative perspectives, there are still a room for improvement from the qualitative perspective, such as its role as a means of governance improvement. Also, based on the above evaluations and consequent findings, I suggest guidelines for the improvement of governance through the development of e-government.
과학 · 수학 · 정보 융합 교육을 통한 중학생의 컴퓨팅 사고력 변화
김성원(Seong-Won Kim),이영준(Youngjun Lee) 한국컴퓨터교육학회 2021 한국컴퓨터교육학회 학술발표대회논문집 Vol.25 No.1(A)
시대의 변화에 따라 창의융합형 인재에 대한 요구가 증가하였다. 이에 따라 한국에서는 STEAM 교육을 학교 현장에 도입하였지만, 융합 교육의 정체성과 교사의 전문성 부족으로 인하여 융합 교육의 도입에 어려움을 겪었다. 따라서 2018년에 ‘과학·수학·정보 교육 진흥법’이 제정되었으며, 과학·수학·정보 융합 교육을 위한 교육 프로그램이 개발되었다. 하지만 과학·수학·정보 융합 교육의 효과를 분석하는 연구가 진행되지 않았다. 따라서 본 연구에서는 중학생을 대상으로 과학·수학·정보 융합 교육의 효과를 분석하는 연구를 진행하였다. 처치로 이영준 외(2018)에서 개발한 과학· 수학·정보 융합 교육 프로그램을 중학생에게 9차시 적용하였다. 과학·수학·정보 융합 교육의 효과를 분석하기 위하여 김성원과 이영준(2020)에서 개발한 중학생의 컴퓨팅 사고력 검사 도구를 사용하였다. 연구 결과, 중학생은 과학·수학·정보 융합 교육을 받은 후, 컴퓨팅 사고력이 향상되는 것으로 나타났다.
ZrB<sub>2</sub>-SiC 복합세라믹스의 미세구조와 열전도도에 미치는 SiC 크기와 첨가량의 영향
김성원,권창섭,오윤석,이성민,김형태,Kim, Seong-Won,Kwon, Chang-Sup,Oh, Yoon-Suk,Lee, Sung-Min,Kim, Hyung-Tae 한국분말야금학회 2012 한국분말재료학회지 (KPMI) Vol.19 No.5
This paper reports the microstructures and thermal conductivities of $ZrB_2$-SiC composite ceramics with size and amount of SiC. We fabricated sintered bodies of $ZrB_2$-x vol.% SiC (x=10, 20, 30) with submicron and nanosized SiC densified by spark plasma sintering. Microstructure retained the initial powder size of especially SiC, except the agglomeration of nanosized SiC. For sintered bodies, thermal conductivities were examined. The observed thermal conductivity values are 40~60 W/mK, which is slightly lower than the reported values. The relation between microstructural parameter and thermal conductivity was also discussed.
나노인덴테이션을 이용한 Ti(C<sub>0.7</sub>N<sub>0.3</sub>)-NbC-Ni 써멧 구성상의 경도평가
김성원,김대민,강신후,류성수,김형태,Kim, Seong-Won,Kim, Dae-Min,Kang, Shin-Hoo,Ryu, Sung-Soo,Kim, Hyung-Tae 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.6
The indentation technique has been one of the most commonly used techniques for the measurement of the mechanical properties of materials due to its experimental ease and speed. Recently, the scope of indentation has been enlarged down to the nanometer range through the development of instrumentations capable of continuously measuring load and displacement. In addition to testing hardness, the elastic modulus of submicron area could be measured from an indentation load-displacement (P-h) curve. In this study, the hardness values of the constituent phases in Ti($C_{0.7}N_{0.3}$)-NbC-Ni cermets were evaluated by nanoindentation. SEM observation of the indented surface was indispensable in order to separate the hardness of each constituent phase since the Ti($C_{0.7}N_{0.3}$)-based cermets have relatively inhomogeneous microstructure. The measured values of hardness using nanoindentation were ${\sim}20$ GPa for hard phase and ${\sim}10$ GPa for binder phase. The effect of NbC addition on hardness was not obvious in this work.
김성원,조강래,Kim, Seong-Won,Jo, Gang-Rae 대한기계학회 1996 大韓機械學會論文集B Vol.20 No.10
The flow analysis method which had been developed for the numerical calculation of 3-dimensional, incompressible and turbulent flow within an axial compressor was extended to the flow field within centrifugal impeller. In this method based on the SIMPLE(Semi Implicit Method Pressure Linked Equations) algorithm, the coordinate transformation was adopted and the standard k-.epsilon. model using wall function was used for turbulent flow analysis. The calculated flow fields have agreed very well with measurement results. Especially, 3-dimensional and viscous flow characteristics including secondary flows, jet-wake flow and decreased pressure rise along impeller passage, which can't be predicted by inviscid Q3D calculation were predicted very reasonably.
치밀화된 Ti(C,N)과 TiC-TiN-Ni 써멧에서의 Ti(C,N) 고용상의 특성평가
김성원,채정민,강신후,류성수,김형태,Kim, Seong-Won,Chae, Jung-Min,Kang, Shin-Hoo,Ryu, Sung-Soo,Kim, Hyung-Tae 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.6
Ti(C,N) solid solutions in hot-pressed Ti($C_{x}N_{1-x}$) (x=0.0, 0.3, 0.5, 0.7, 1.0) and 40TiC-40TiN-20Ni (in wt.%) cermet were characterized in this study. For hot-pressed Ti(C,N)s, the lattice parameters and hardness values of Ti(C,N) were determined by using XRD (X-Ray Diffraction) and nanoindentation. The properties of hot-pressed Ti(C,N) samples changed linearly with their carbon or nitrogen contents. For the TiC-TiN-Ni cermet, the hardness of the hard phase and binder phase were determined by nanoindentation in conjunction with microstructural observation. The measured hardness values were ${\sim}8.7$ GPa for the binder phase and ${\sim}28.7$ GPa for the hard phase, which was close to the hardness of hot-pressed Ti($C_{0.7}N_{0.3}$).