• Computational Structural Engineering
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• v.8 no.1
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• pp.147-160
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• 1995

Based on the weighted residual concept[4], a three-dimensional plate theory is derived using a Fourier series expansion of a dependent variable and a weighted residual approximation of the basic elasticity equations. The weighted residual equilibrium equations of the plate are expressed in terms of weighted displaced quantities, and the results are then interpreted by means of a potential energy functional. The potential energy expression is used to develop a finite element implementation. For illustrative purposes, the application of the theory to a strip plate is considered and two numerical examples of a cantilever and a simply-supported strip plate are studied.

• Journal of the Korean Society of Earth Science Education
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• v.7 no.2
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• pp.214-225
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• 2014

This study aimed to investigate the high school students' conceptions about the plate tectonics through visual representation. For this purpose, the subjects were 67 students in 11th-grade high schools in Chungbuk. In order to in-depth understand the students' conceptions about plate tectonics, so the investigator conducted a semi-structured interview. The conclusions were as in the following. After learning the plate tectonics, the students had the alternative conceptions associated with terminology, colors' meanings, plate-related melting, plate's movement, plates' boundaries, mantle's physical conditions, driving forces for plate movement, and they had the organic relations about colors' meanings, mantle's physical conditions, and driving forces of plate movement. Also, the visual representation used to teach plate tectonics influenced on the students' responses about terminology, plates' boundaries, plate-related melting and the mantle's physical features, also this study found the factors of visual representation causing the learners to create alternative conceptions. These results implicated the importance of teacher's role in identifying the students' interpretation process on visual representation, and it needed to improve the factors creating students' alternative conceptions about visual representation and to study the factors further.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.346-347
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• 2012

최근 화석연료 대체 에너지원으로서 자동차용으로 연구 개발 및 응용되고 있는 고분자 전해질 연료전지(PEMFC: Proton exchange membrane fuel cells)에서 분리판(Bipolar Plate)은 스택 전체 무게의 80%, 스택 가격의 60% 정도로 가장 높은 비중을 차지한다. 분리판은 연료와 산화제를 공급해주는 통로 및 전지 운전 중에 생성된 물을 제거하는 통로 역할과 anode, cathode로서 전극 역할을 통해 스택 전력을 형성하는 핵심 기능과 전지와 전지 사이의 지지대 역할을 한다. 따라서 분리판은 전기전도성, 내부식성 및 기계적 특성이 우수해야함은 물론이고, 얇고 가벼우며 가공성이 뛰어나야 한다. 현재 가장 많이 사용되고 있는 금속 분리판 소재 중 스테인리스 스틸은 전기적, 기계적 특성 및 내부식성이 우수한 반면, 가격이 비싸고, 중량이 무거운 단점이 있다. 따라서 본 연구에서는 DC 반응성 마그네트론 스퍼터링법으로 전기적, 기계적 특성 및 내부 식성이 우수한 TiN, TiCN 박막을 스테인리스에 비해 중량이 1/3, 소재 단가가 1/4인 알루미늄 기판 위에 증착하여 박막 물성을 평가하였다. DC Power는 400 W, 기판과 타겟 사이의 거리는100 mm, 공정 압력은 0.5 Pa로 고정하였고, 3 inch의 지름과 순도 99.95%를 갖는 티타늄 타겟을 사용하였다. 공정 가스는 Ar을 주입하였으며, 질소와 탄소의 공급원으로는 질소($N_2$)와 메탄($CH_4$) 가스를 사용하여 챔버 내 주입혼합가스의 전체 유량을 50 sccm으로 고정시켰다. 증착된 박막의 전기적, 기계적 특성을 측정하였고, X-ray diffraction (XRD), Scanning electron microscope (SEM)을 이용하여 박막의 미세구조 및 표면 상태를 확인하였다. 또한, 내부식 특성을 평가하기 위해 potentiostatic, potentiodynamic 법을 이용하여 박막의 부식저항을 측정하였다. 증착된 TiN 박막의 경우 질소 함량의 증가에 따라 박막 증착속도는 감소하는 경향을 보였다. 이는 타겟 부근의 질소 라디칼 비율이 증가함에 따라 질화반응이 촉진된 것으로 생각된다. 또한, 증착된 TiN과 TiCN 박막은 반응성 질소 유량과 탄소 유량에 따라 각각 다른 미세구조를 가지는 것을 확인하였다. TiN과 TiCN은 NaCl형의 면심입방격자(FCC)로 같은 구조이며, 격자상수가 비슷하여 전율고용되어 TiCN을 형성하고, 탄소와 질소의 비에 따라 전기적 기계적 특성이 달라짐을 확인하였다.

• Journal of the Korean earth science society
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• v.37 no.1
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• pp.62-77
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• 2016

In the early model of plate tectonics, the plate was depicted as a passive raft floating on the convecting mantle and carried away by the mantle flow. At the same time, ridge push at spreading boundaries and drag force exerted by the mantle on the base of lithosphere were described as the dominant driving forces of plate movements. However, in recent studies of plate tectonics, it is generally accepted that the primary force driving plate motion is slab pull beneath subduction zones rather than other forces driven by mantle convection. The current view asserts that the density contrast between dense oceanic lithosphere and underlying asthenosphere is the substance of slab pull. The greater density of oceanic slab allows it to sink deeper into mantle at trenches by gravitational pull, which provides a dominant driving force for plate motion. Based on this plate tectonics development, this study investigated the contents of plate tectonics in high school Earth Science textbooks and how they have been depicted for the last few decades. Results showed that the early explanation of plate movement driven by mantle convection has been consistently highlighted in almost all high school textbooks since the 5th curriculum, whereas most introductory college textbooks rectified the early theory of plate movement and introduced a newly accepted theory in revised edition. Therefore, we suggest that the latest theory of plate tectonics be included in high school textbooks so that students get updated with recent understanding of it in a timely manner.

• KLA journal
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• v.11 no.12
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• pp.13-15
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• 1970

이 글은 1970년 11월 7일 이화여자대학교 도서관에서 개최된 ‘한국도서관학회 제1회 학술발표회’에서 발표된 필자의 발표논문 요지이다. 이 논문은 원래 ‘표의 구조론에 입각한 우리 나라 저자기호법의 연구’와 ‘저자기호법에 있어서 한글의 기호삼기 문제에 대하여-기호법의 요건과 Syllabic Notation의 원리에 입각한 고찰-’과 ‘동서저자 기호표(제2판, 개정판)의 구성원리와 사용원칙’이란 제목으로 되어 있는 세편의 독립된 논문인데 동학회 학술발표회를 위하여 Ⅰ,Ⅱ,Ⅲ,으로 요약하여 발효한 것이다. 이 논문들의 지상발표는 Ⅰ은 한국도서관학회지 제1집에, Ⅱ는 연세학교 Ⅱ‘인문과학’ 제24집(1970년 12월)에, Ⅲ은 본 기관지에 각각 실릴 예정이다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.19 no.1 s.71
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• pp.73-83
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• 2006

The failure mechanism of a hollow bridge deck which is made of fiber reinforced polymer (FRP) to improve its durability and life time significantly is investigated using both experiments and analyses. While the Load-displacement behavior of the deck in the longitudinal direction is almost linear just before the failure, the behavior in the transverse direction shows a strong nonlinearity even in its initial response with relatively small magnitude of loads. We found that the nonlinearity is due to the imperfection of the connection between the flange and the web; a plastic deformation can t라e place in the connection. The argument is demonstrated using a simple structural model in which a rigid plastic hinge is introduced to the connection. We also checked the contribution of the delamination mechanism to the failure. But the delamination is not the main mechanism which initiates and causes the failure of the bridge deck. In order to improved the structural behavior of the deck in the transverse direction, we suggested that the empty space of the bridge deck is filled with a foam and confirmed the improved behavior by a numerical analysis.

• Geophysics and Geophysical Exploration
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• v.27 no.1
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• pp.1-22
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• 2024

Carbon dioxide capture utilization and storage (CCUS) techniques have received significant global attention as they are part of efforts to achieve carbon neutrality by 2050. Large-scale carbon dioxide capture and storage (CCS) projects are being actively pursued in North America, the North Sea, the Middle East, and Oceania. Considering the current situation in South Korea, identifying large-scale CCS sites that can secure an annual domestic carbon storage capacity of 30 million tons by 2050 is crucial Therefore, this study analyzed the formation process and geological characteristics of overseas large-scale CCS projects in terms of plate tectonics. We utilized the GPlates program to interpret the formation processes of large-scale CCS projects in North America, the North Sea, Middle East, and Oceania from the perspective of plate tectonics. Additionally, we investigated the geological structure of the CO₂ storage layer and interpreted seismic imaging results obtained from each CCS site. This study will help identify a domestic large-scale CCS site.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.16 no.1
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• pp.87-94
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• 2003

A geometric non-linear finite element formulation of CRTS reflector subjected to displacement loads, corresponding to the successional assembly steps of the reflector, is presented in order to determine the initial static equilibrium state based on the displacement incremental method. Parametric analyses of the influence of cables and mechanical properties of the reflector on the shape error between reference and equilibrium surfaces have been studied. These results of the present study are compared with the others using Galerkin mothod and NASS 98 program to demonstrate the feasibility.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.10
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• pp.1177-1183
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• 2010

In this paper, design of a microstrip-fed, Spidron fractal-shaped slot antenna with circular polarization is represented. The ground plane of the designed antenna has a slot that comprises seven right-angled triangle next to each other in a low. A reflector is placed at the bottom on microstrip feeding line to enhance the antenna gain. The optimized design was conducted by varying a length of the first right-angled triangle, location of feeding line, space between a substrate and a reflector. The proposed antenna was fabricated on a Taconic-RF35 substrate. The entire dimension of the fabricated antenna is $40{\times}40{\times}18.6mm^3$ and the reflector is 18.6 mm away from the ground plane. The measured gain of the fabricated antenna is 6.7 dBi at 4.3 GHz. The measured bandwidths of -10 dB reflection and 3 dB axial ratio are 41 % and 7.4 %, respectively.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.3
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• pp.35-40
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• 2010

The specially orthotropic plate theory is used for analysis of panels made of girders and cross-beams. The cross-sections of both girders and cross-beams are H-types. The results of application of this method to rolled beam bridge by using specially orthotropic plate theory is presented. The result is compared with that of the beam theory. Finite difference method is used for this purpose. The influence of the $D_{22}$ stiffness on the natural frequency is rigorously investigated. According to numerical examination given in this paper, the result by the plate theory is 2.43 times stiffer than that of beam theory.