졸-겔공정/광증착법을 이용한 Ag-Doped TiO₂ 합성 및 광촉매 특성

김병민,김정식,Kim, Byeong-Min,Kim, Jung-Sik 한국재료학회 2016 한국재료학회지 Vol.26 No.2

$TiO_2$ nanoparticles were synthesized by a sol-gel process using titanium tetra isopropoxide as a precursor at room temperature. Ag-doped $TiO_2$ nanoparticles were prepared by photoreduction of $AgNO_3$ on $TiO_2$ under UV light irradiation and calcinated at $400^{\circ}C$. Ag-doped $TiO_2$ nanoparticles were characterized for their structural and morphological properties by X-ray diffractometry (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The photocatalytic properties of the $TiO_2$ and Ag-doped $TiO_2$ nanoparticles were evaluated according to the degree of photocatalytic degradation of gaseous benzene under UV and visible light irradiation. To estimate the rate of photolysis under UV (${\lambda}=365nm$) and visible (${\lambda}{\geq}410nm$) light, the residual concentration of benzene was monitored by gas chromatography (GC). Both undoped/doped nanoparticles showed about 80 % of photolysis of benzene under UV light. However, under visible light irradiation Ag-doped $TiO_2$ nanoparticles exhibited a photocatalytic reaction toward the photodegradation of benzene more efficient than that of bare $TiO_2$. The enhanced photocatalytic reaction of Ag-doped $TiO_2$ nanoparticles is attributed to the decrease in the activation energy and to the existence of Ag in the $TiO_2$ host lattice, which increases the absorption capacity in the visible region by acting as an electron trapper and promotes charge separation of the photoinduced electrons ($e^-$) and holes ($h^+$). The use of Ag-doped $TiO_2$ nanoparticles preserved the option of an environmentally benign photocatalytic reaction using visible light; These particles can be applicable to environmental cleaning applications.

CLOSE UP - 라파즈한라시멘트 콘크리트연구소

김병민,Kim, Byeong-Min 한국시멘트협회 2013 시멘트 Vol.199 No.-

라파즈한라시멘트는 지속적인 연구개발을 통한 양질의 시멘트 생산을 통해 그간 국가기간산업 발전에 기여해왔다. 그리고 그 중심에는 라파즈한라시멘트 콘크리트 연구소가 있다. 이는 전신인 한라시멘트 기술연구소에서부터 시작해 시멘트 및 콘크리트 기초 연구 및 신제품의 개발에 역량을 집중함으로써 라파즈한라가 지속가능한 발전을 할 수 있도록 혁신의 토대를 제공해왔기 때문이다. 앞으로도 콘크리트 연구소는 기업과 고객이 상호 윈-윈할 수 있는 전략적 사고를 바탕으로 최고의 기술지원 서비스를 제공함으로써 대 고객 서비스 수준을 제고시켜 나갈 계획이다.

기후변화 적응을 위한 수자원 거버넌스와 성공적 시민참여 요인에 관한 논의

김병민,윤지웅,이은선,김영오,Kim, Byeong-Min,Yun, Ji-Ung,Lee, Eun-Seon,Kim, Yeong-O 한국수자원학회 2016 물과 미래(한국수자원학회지) Vol.49 No.3

FRP 바닥판의 약축방향 파괴모드에 관한 연구

김병민,황윤국,이영호,강영종,지광습,Kim Byeong-Min,Hwang Yoon-Koog,Lee Young-Ho,Kang Young-Jong,Zi Goang-Seup 한국전산구조공학회 2006 한국전산구조공학회논문집 Vol.19 No.1

본 논문에서는 내구성과 수명을 획기적으로 향상시키기 위해 제3세대 건설재료인 섬유강화 플라스틱(FRP) 소재로 제작된 사각형 중공 교량 바닥판의 파괴모드를 실험과 해석을 통해 분석하였다. 재하시험 결과 바닥판의 강축방향의 거동은 파괴 직전까지도 거의 선형탄성적으로 거동한 반면, 약축방향의 거동은 재하초기부터 작은 하중하에서도 큰 비선형성을 보였다. 이 약축방향 비선형성의 원인은 웨브와 플랜지 연결부의 불완전한 일체거동으로 인한 소성거동 때문인 것으로 판단된다. 웨브와 플랜지의 연결부에 소성힌지를 도입한 간단한 구조모델을 이용하여 이를 확인하였다. 접착부의 박리 파괴 가능성도 검토하였으나 이는 대상 중공바닥판의 약축방향 파괴에 직접적으로 관여하는 것은 아닌 것으로 판단된다 약축방향의 구조거동을 개선시키기 위한 방안으로 내부를 폼으로 충전하는 방법을 제시하였으며 그 가능성을 구조해석을 통해 확인하였다. 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.

온.열간 단조 공정에서 금형 수명 예측 및 향상 기법

김병민,이정환,이영선,권용남,Kim, Byeong-Min,Lee, Jeong-Hwan,Lee, Yeong-Seon,Gwon, Yong-Nam 재료연구소 2005 機械와 材料 Vol.17 No.3

해상풍력자원 예측을 위한 NCAR데이터 적용 타당성 연구

김병민(Kim Byeong-min),김현기(Kim Hyeon-gi),우재균(Woo Jae-kyoo),백인수(Paek In-su),유능수(Yoo Neung-soo) 한국태양에너지학회 2012 한국태양에너지학회 논문집 Vol.32 No.1

Predictions of wind speed for six different near-shore sites were made using the NCAR (National Center for Atmospheric Research) wind data. The distances between the NCAR sites and prediction sites were varied between 40㎞ and 150㎞. A well-known wind energy prediction program, WindPRO, was used. The prediction results were compared with the measured data from the AWS(Automated Weather Stations). Although the NCAR wind data were located far away from the AWS sites, the prediction errors were within 9% for all the cases. In terms of sector-wise wind energy distributions, the predictions were fairly close to the measurements, and the error in predicting main wind direction was less than 30º. This proves that the NCAR wind data are very useful in roughly estimating wind energy in offshore or near-shore sites where offshore wind farm might be constructed in Korea.

폼 충전 FRP 바닥판의 교축방향 거동에 대한 실험적 연구

김병민(Kim Byeong Min),지광습(Zi Goangseup),황윤국(Hwang Yoon Koog),이영호(Lee Young Ho) 대한토목학회 2006 대한토목학회 학술대회 Vol.2006 No.10

폼 충전 FRP 바닥판의 약축방향 정적거동 특성에 관한 실험적 연구

김병민(Kim Byeong Min),지광습(Zi Goangseup),황윤국(Hwang Yoon Koog),이영호(Lee Young Ho) 대한토목학회 2006 대한토목학회논문집 A Vol.26 No.6A

본 연구에서는 섬유강화 플라스틱(FRP) 소재로 제작된 사각형 중공 교량 바닥판의 약축방향 거동을 보완하기 위해서 바닥판의 중공 내부를 구조용 폼(foam)으로 충전하였다. 충전폼의 유무와 폼의 강도에 따른 약축방향 정적거동 특성을 실험적으로 분석하여 충전폼의 역할을 검토하였다. FRP에 비하여 탄성계수가 현저히 낮은 구조용 폼으로 바닥판 내부를 충전하여도 본래의 경량성을 유지하면서 공칭강도, 강성 등의 횡방향 구조성능이 획기적으로 개선되었다. 웨브의 개수에 따른 파괴거동을 비교하여 내부충전 FRP 바닥판에서 웨브의 역할을 파악하였다. 웨브가 내부충전 FRP 바닥판의 약축방향 강도에 미치는 영향은 미미하였으나, 폼 내부에서 발생한 균열의 전파를 차단함으로써 파괴모드의 취성을 경감시켰다. We investigated experimentally the static behavior of an orthotropic bridge deck which is made from glass fiber reinforced polymer (GFRP) and polyurethane foam. The bridge deck consists of many unit cells with rectangular holes which are filled with the foam to improve its structural behavior in its weak axis. It is found that although the elastic modulus of the foam compared to that of the GFRP is about the order of, the structural behaviors in the weak axis such as nominal strength, stiffness, etc. are greatly improved. Owing to the low mass density of the foam used in this study, the bridge deck is still light enough with the improved structural properties. Webs of the cells filled with the foam did not significantly contribute to the strength development of the deck. However, the propagation of a crack initiated in a cell is caught by the webs and limited to the inside of that cell only, which makes the load-displacement behavior of the foam-filled GFRP deck less brittle.

고탄소강의 연속 건식 신선 공정에서 선재의 온도 예측 기법 개발

김영식,김동환,김병민,김민안,박용민,Kim, Yeong-Sik,Kim, Dong-Hwan,Kim, Byeong-Min,Kim, Min-An,Park, Yong-Min 대한기계학회 2001 大韓機械學會論文集A Vol.25 No.2

Wire drawing process of the high carbon steel with a high speed is usually conducted at room temperature using a number of passes or reductions through consequently located dies. In multi-stage drawing process, temperature rise in each pass affects the mechanical properties of final product such as bend, twist and tensile strength. Also, this temperature rise during the deformation is the reason that the wire in drawing process is broken by the embrittlement due to rapid strain aging effect. This paper presents the estimation of the wire temperature for the multi-stage wire drawing process. Using the proposed calculation method of wire temperature, temperature rise at deformation zone as well as temperature drop in block considering the heat transfer between the block and wire were calculated. As these calculated wire temperatures were applied to the real industrial fields, it was known that the calculated results were in a good agreement with the measured wire temperature.

허브 냉간단조품의 공정설계

고대철,김병민,오세욱,Go, Dae-Cheol,Kim, Byeong-Min,O, Se-Uk 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.11

The Hub is an auto mobile component used as aircon clutch. The important aspects in cold forging of the Hub with complex geometry are the design of an initial shape of the workpiece, the possibility of the forming by one-stage operation and the determination of number of performs, etc. Based on the systematic procedure of process sequence design, in this paper, the forming operation of cold forged part of the Hub is designed by the rigid-plastic finite element method. The two design criterion of geometrical filling without defect and an even distribution of effective strain in final product are investigated in controlling the initial shape of the workpiece and preform configuration. It is noted that one preforming operation is required in order to obtain final product of the Hub.