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오택근,황원정,이종운,차종문,Oh, Taek-Geun,Hwang, Won-Jeong,Lee, Jong-Un,Cha, Jongmun 한국자원리싸이클링학회 2016 資源 리싸이클링 Vol.25 No.3
산성광산배수(Acid mine drainage; AMD)를 처리하기 위한 자연정화시설의 반응조는 긴 체류시간을 위해 넓은 면적이 요구되며, 집중호우로 인해 유량이 급격히 늘어나는 여름에는 체류시간 부족으로 반응이 충분히 일어나지 못하고 많은 오염물질이 유출수로 빠져나가는 현상이 발생한다. 본 연구에서는 국내 부지 및 환경 특성으로 인해 넓은 면적이 요구되는 자연정화시설을 설치하기에 어려움이 있는 폐광산의 AMD에 응집제를 사용하여 빠른 시간 내에 오염물질을 침전시키고 탁도를 개선하는 연구를 진행하였다. W광산에서 배출되는 AMD에 무기응집제 PAC (Poly Aluminium Chloride)와 유기응집제인 PAM (Polyacrylamide) 성분이 포함된 고분자응집제를 사용하여 AMD의 상등수 및 여액의 중금속 농도와 침전된 슬러지의 형태를 파악하기 위해 입도분석, ICP-OES, SEM-EDS 분석을 실시하였다. The passive treatment was required a large area for the treatment of acid mine drainage (AMD), and pollutants were discharged with mine drainage by the increased flow rate in summer. This study was performed to improve the turbidity and to precipitate the pollutants quickly using coagulants and flocculants in AMD of abandoned mine sites that were difficult to build the passive treatment system. The coagulant PAC (Poly aluminium chloride) and flocculant PAM (Polyacrylamide) were selected to improve turbidity in W mine waters. We also tested the particle size analysis, ICP-OES and/or SEM-EDS for water and sludge samples.
소형 발사체 원격측정시스템을 위한 링크 버짓 모델 및 시뮬레이터 개발
오택근 ( Taeckkeun Oh ),이유상 ( You-sang Lee ),이대현 ( Dae-hyun Lee ),이온수 ( Onsoo Lee ) 한국항행학회 2024 韓國航行學會論文誌 Vol.28 No.3
본 논문에서는 소형 발사체의 원격측정시스템 링크 버짓 모델을 제안하고, 제안한 링크 버짓 모델을 바탕으로 링크 버짓 시뮬레이터를 구현하였다. 제안하는 링크 버짓 모델은 기하학적 모델과 전파 손실 모델로 구성되어 있다. 기하학적 모델은 지상국과 소형 발사체 사이의 시선각을 계산하기 위한 모델이다. 전파 손실 모델은 소형 발사체 비행 환경에 적합하도록 자유공간 손실과 소형 발사체의 시선각 및 안테나 방사 패턴 기반의 편파 손실, 지향 손실로 구성되어 있어, 복잡한 전파 환경에 대한 계산 없이 전파 손실을 계산 할 수 있다. 링크 버짓 시뮬레이터는 제안하는 링크 버짓 모델을 기반으로 MATLAB으로 구현하였으며, 지상국 위치 및 소형 발사체의 궤적, 안테나의 방사 패턴 등을 기반으로, 소형 발사체의 시선각, 자유공간 손실, 편파 손실 파라미터, 지향 손실, 지상국에서의 수신 신호 레벨 등을 계산한다. In this paper, telemetry link budget model for small launch vehicle is proposed, and telemetry link budget simulator is implemented. The proposed link budget model consist of geometry model and propagation loss model. The geometry model is calculation of look angle between ground station and small launch vehicle. The propagation loss model consist of free space loss, polarization loss, and de-pointing loss which are appropriate to the small launch vehicle flight environment. The proposed propagation loss model can be calculate propagation loss without complex calculation of propagation environments. The link budget simulator is implemented in MATLAB. The simulator calculate look angle, free space loss, polarization loss parameter, de-pointing loss and received signal level in ground station by using position of ground station, routing of small launch vehicle, 3-D radiation patterns of antennas.
초고성능 섬유보강 콘크리트의 역학적 성능 향상을 위한 매트릭스 강화 및 섬유표면개질
오택근(Taekgeun Oh),김기웅(Gi-woong Kim),이승원(Seung Won Lee),류두열(Doo-yeol Yoo) 한국방재학회 2023 한국방재학회논문집 Vol.23 No.1
본 연구에서는 초고성능 섬유보강 콘크리트(Ultra-high-performance fiber-reinforced concrete)의 성능 향상을 위해 충전재와 실리카 퓸을 각각 LCD 유리 분말(Liquid crystal display glass powder, LCDGP)와 나노실리카로 치환하였다. 또한, 섬유와 UHPC 매트릭스 계면마찰력 증진을 위해 에틸렌디아민사초산(ethylendiaminetetraacetic acid, EDTA)용액으로 강섬유 표면을 개질하였다. LCDGP와 나노실리카 모두 수산화칼슘과 반응하여 수화물을 형성하는 것으로 나타났으며 EDTA 처리를 통해 섬유 표면거칠기가 증가하였다. LCDGP 혼입 시 packing density 감소에 의한 압축강도 감소가 나타났으나, 나노실리카의 혼입으로 UHPFRC의 압축강도 및 인장강도가 향상되었다. 섬유의 표면개질은 UHPC 매트릭스와 섬유 계면의 마찰력을 향상시키기 때문에 압축강도보다는 인장강도 향상에 더 효과적인 것으로 나타났다. In this study, filler and silica fume were substituted by Liquid crystal display glass powder (LCDGP) and nanosilica, respectively, to improve the performance of ultra-high- performance fiber-reinforced concrete. In addition, the surface of steel fiber was modified with ethylenediaminetetraacetic acid (EDTA) solution to improve the interfacial friction between the fiber and Ultra-high-performanceconcrete (UHPC) matrix. Both LCDGP and nanosilica reacted with calcium hydroxide to form hydrates, and the fiber surface roughness increased owing to the EDTA treatment. When LCDGP was used, the compressive strength decreased owing to a decrease in packing density; however, the compressive and tensile strengths of Ultra-high-performance fiber-reinforced-concrete (UHPFRC) were improved on using nanosilica. It was observed that the surface modification of the fiber increased the friction force between the UHPC and fiber interface; therefore, it was more effective in improving the tensile strength than the compressive strength.
고등학교 수학 학습부진학생을 위한 프로그램 개발 및 적용-ADDIE 모형 적용 사례-
오택근 ( Oh Taek-keun ) 한국수학교육학회 2018 수학교육 Vol.57 No.4
This study analyzed each process of demand analysis(A), design(D), development(D), implementation(I) and evaluation(E) of the program to support mathematics learning of students with under-achievement of math in high school. To analyze the demand, a survey was conducted on 235 high school math teachers and 334 high school students who were under-achieved in mathematics. To design and develope the program, this study linked middle school math to high school math so that the students with poor math learning could easily participate in mathematics learning. The programs developed in this study were implemented in three high schools, where separate classes were organized and run for students with poor math learning. The evaluation of the programs developed in this study was done in two ways. One was a quantitative evaluation conducted by five experts, and the other was a qualitative evaluation conducted through interviews with teachers and students participating in the program. This study found that students with poor mathematics learning were more motivated to learn, started to do mathematics, and encouraged to be confident when using learning materials that included easy problems and detailed solutions that they could solve themselves. From these results, the following three implications can be derived in developing a program to support students who are experiencing poor mathematics learning in high school. First, we should develop learning materials that link middle school mathematics to high school mathematics so that students can supplement middle school mathematics related to high school mathematics. Second, we need to develop learning materials that include detailed solutions to basic examples and include homogeneous problems that can be solved while looking at the basic example’s solution process. Third, we should avoid the challenge of asking students who are under-achieving to respond too openly.