• Electrical & Electronic Materials
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• v.35 no.6
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• pp.38-45
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• 2022

• Economic and Environmental Geology
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• v.55 no.6
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• pp.661-669
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• 2022

The need for miniaturization, high efficiency, and green energy resources as an energy storage device through the development of various electronic device has emerged. Accordingly, nanomaterials with excellent electrochemical properties, such as graphene and graphene hybrids, are attracting attention as promising materials. In particular, in the electric vehicle industry, cost reduction of secondary batteries is a key factor that can determine the spread of related industries, and it is most important to analyze R&D trends for battery material technology and respond to future technological development directions. Therefore, in this study, we tried to suggest a direction for R&D activities in the future by analyzing patent trends for graphene anode material technology for secondary batteries and deriving implications. As a result, in the case of anode material technology, the proportion of foreigners in the US and European patent markets was higher than in the Korean and Japanese patent markets, which means that the US and European marketability is high. In addition, Japanese applicants are filing high-level applications not only in the Japanese patent market but also in other countries suggests that Japan is leading the technology in this field. Lastly, the proportion of research institutes in the patent market of Korea and the US remains high compared to that of Japan and Europe, indicating that the commercialization of technology is still slow in those countries. Therefore research institutes and companies in Korea will have to establish their own strategies for developing and securing materials using the results of patent trends in major countries and major companies analyzed in this study.

• Journal of the Korean Chemical Society
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• v.47 no.5
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• pp.447-459
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• 2003

Generalized 2D correlation spectroscopy has been applied extensively to the analysis of spectral data sets obtained during the observation of a system under some external perturbation. It is used in various fields of spectroscopy including IR, Raman, UV, fluorescence, X-ray diffraction, and X-ray absorption spectroscopy (XAS) as well as chromatography. 2D hetero-spectral correlation analysis compares two completely different types of spectra obtained for a system under the same perturbation. Because of the wide range of applications of this technique, it has become one of the standard analytical techniques for the analytical chemistry, physical chemistry, biochemistry, and so on, and for studies of polymers, biomolecules, nanomaterials, etc. In this paper, we will introduce the principle of generalized 2D correlation spectroscopy and its applications that we have studied.

• School Mathematics
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• v.13 no.3
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• pp.447-468
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• 2011

For the instruction of units dealing with the conic section, the most important factor that we need to consider is the connections. In other words, the algebraic approach and the geometric approach should be instructed in parallel at the same time. In particular, for the students of low proficiency who are not good at algebraic operation, the geometric approach that employs visual representation, expressing the conic section's characteristic in a dynamic manner, is an important and effective method. For this, during this research, to suggest the importance of dynamic visual representation based on GeoGebra in teaching Quadratic Curve, we taught an experimental class that suggests the instruction method which maximizes the visual representation and analyzed changes in the representation of students by analyzing the part related to the unit of a parabola from units dealing with a conic section in the "Geometry and Vector" textbook and activity book.

• Communications for Statistical Applications and Methods
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• v.2 no.2
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• pp.414-422
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• 1995

본 논문에서는 그래픽스에 의한 판별분석을 다루고 있다. 본 논문에서 제안하는 새로운 그래프는 표본이차판별함수에 기초하고 있으며 기존의 MV 그래프와 실제자료에 대하여 비교하고 있다. 판별분석에서 공분한행렬이 같지 않은 경우의 3차원 그래프는 처음 시도된 것으로 이를 위하여 차원축소문제를 논의하고 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.912-915
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• 2005

본 연구에서는 현재 이용 가능한 지상관측자료와 이차원 원격관측자료를 이용하여 장기간의 지역기후변화 특성을 분석하였다. 기상자료로는 강수량, 기온, 습도, 대형$\cdot$소형 팬 증발량 등을 월별, 연별로 분석하였고 이차원 원격관측자료로 정규식생지수를 사용하여 전통적 도시화지역, 산업화로 급격하게 도시화가 된 지역, 비도시지역으로 나누어 경향성분석을 실시하였다. 강수량과 기온은 관측전지점에서 증가추세를 보였고 도시화된 지역이 비도시지역보다 그 변화 추이가 강함을 볼수 있었다. 정규식생지수분석결과 도시화의 영향을 더 뚜렷이 관측할수 있었는데 도시지역은 정규식생지수값이 감소추세를 나타내는 반면 비도시지역인 소양강$\cdot$안동댐은 증가추세를 나타내었다.

• School Mathematics
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• v.18 no.1
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• pp.127-141
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• 2016

This study analyzes modes related to use of graph representation that appears to solve high school students quadratic function problem based on the graph using modes of Chauvat. It was examined the extent of understanding of the quadratic function of students through the flexibility of the representation of the Bannister (2014) from the analysis. As a result, the graph representation mode in which a high school students are mainly used is a nomographic specific mode, when using operational mode, it was found to be an error. The flexibility of Bannister(2014) that were classified to the use of representation from the point of view of the object and the process in the understanding of the function was constrained operation does not occur between the two representations in understanding the function in the process of perspective. Based on these results, the teaching on use graph representation for the students in classroom is required and the study of teaching and learning methods can understand the function from various perspectives is needed.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.558-558
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• 2012

다수의 자연 하천은 유사 이동과 하안의 침식으로 인하여 사행 하천이 발생한다. 사행 하천에서의 이차류는 원심력, 편수위로 발생하는 중력에 의한 압력차, 그리고 난류로 인하여 발생하는 응력으로 인하여 형성되며 나선형 구조 형태로 표면 유속은 외부로 향하고 하천 바닥의 유속은 안으로 향하게 된다. 이러한 2차류의 형성은 주 흐름의 특성을 변형시킨다. 자연하천에서 2차류는 주 흐름의 15-25%의 크기를 가지고 있으나, 하상의 변화, 유사의 이동 등과 연관되므로 2차류의 영향을 정확히 해석하는 것은 수리학적으로 매우 중요하다. 본 연구에서는 사행수로에서 발생하는 2차류 거동을 수치모의를 통하여 수행하였다. 우선 2차류의 분석을 위하여 실험을 통한 결과물을 비교하였다. 자연 하천의 특성을 반영할 수 있도록 서일원(2006)이 수행한 S-자 형태의 실험 수로의 실험 결과를 분석하였다. 수치 모의를 위하여 3차원 전산유체역학 프로그램을 사용하여 사행수로의 2차원 유속 구조를 모의할 수 있도록 하였다. FLOW-3D 프로그램을 이용하여 실험 결과와 모의 결과를 비교할 수 있도록 하였으며 비교 후 보정을 실시하였다. 모의는 주로 LES (Large Eddy Simulation) 모형을 통해 이루어졌으며, 이를 통하여 실험에서 획득한 결과와 비슷한 유속구조 분포를 확인할 수 있었다. 보정 및 검증 후 수치 모의를 통한 유속 데이터를 이용하여 민감도 분석을 실행하였다. 이후로는 수로의 만곡부, 조도, 수심 등 인공수로의 조건을 변경하여 수치 모의를 수행하였다. 보정된 결과를 이용하여 추가적인 모의를 통한 유속 분포 구조의 비교가 이루어졌다. 이를 통하여 각 조건이 이차류의 크기에 미치는 영향을 확인할 수 있었으며, 모의를 통한 유속분포 결과는 대체적으로 실험을 통한 이차류의 연직분포 구조와 일치하였다.

• Ecology and Resilient Infrastructure
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• v.5 no.4
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• pp.199-209
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• 2018

In river design, consideration of bed shear stresses is necessary to secure stability of levee and floodplain. In this study distributions of bed shear stresses in compound open channels are analyzed through numerical simulation for various width and depth. LES solver in OpenFOAM is applied to 12 cases of compound channel shapes considering secondary flow which effects distributions of bed shear stresses. By the results time averaged velocity distributions, secondary currents, and distributions of bed shear stresses are analyzed. Overall distributions of bed shears in floodplain show that higher shear stresses are seen in left of floodplain and the shears decrease toward right of floodplain. However, high local variations in shear stresses are shown due to the secondary flow effects. In shallow floodplain, bed shear stresses show low value below 0.8 times of averaged bed shear. In deep floodplain, bed shear stresses show high value over 1.2 - 1.4 times of averaged bed shear.

• Journal of Wetlands Research
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• v.18 no.4
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• pp.357-362
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• 2016

Improvement of the solid-liquid separation efficiency in the secondary sedimentation tank of the biological treatment process, is known to be increasing effectiveness of the overall system operation. Sewage treatment plant effluent SS is composed of most organic substances. In order to reduce the SS component in the secondary sedimentation tank discharge, fine SS components constituting the heterogeneous should be increased by its own aggregation (self flocculation), so that can be deleted through their precipitation. So, it is improved through using the installation of double rectification wall in this secondary tank. In case, sewage is rapidly increased due to the daily change of the influent water, it was confirmed that suspended solids caused by the impact load are processed stably. Therefore, there is a need for a facility installation which can be its own aggregation for reduction suspended solids in secondary sedimentation tank.