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레이저와 연속광원을 이용한 매연입자 광 소멸의 파장 의존성
임상철(Sangchul Lim),안태국(Teakook Ahn),박선호(Sunho Park),남연우(Younwoo Nam),이원남(Wonnam Lee) 한국연소학회 2015 KOSCOSYMPOSIUM논문집 Vol.2015 No.5
The dependency of wavelength on the light extinction due to the presence of soot particles has been experimentally studied with ethylene and propane co-flow diffusion flames under elevated pressure conditions. The wavelength dependency was not observed at the soot oxidation/emission region: however, the weak dependency of wavelength was observed at the soot formation region in diffusion flames.
임상철(Sangchul Lim),이승훈(Seunghoon Lee),안태국(Teakook Ahn),남연우(Younwoo Nam),박선호(Sunho Park) 한국연소학회 2015 KOSCOSYMPOSIUM논문집 Vol.2015 No.12
Light extinction characteristics of soot particles in ethylene and propane inverse diffusion flames have been experimentally investigated. The measured data suggested that the refractive index of soot particles varies with light wavelength due to PAH contents existing during the soot growth process. The results showed that the scattering effect is less important as the size of secondary particles rarely affects the optical properties of the soot even when the size is large enough to deviate from Rayleigh assumptions.
연료의 황 함량에 따른 열분해 매연입자 특성화의 실험적 연구
이승훈(Seunghoon Lee),임상철(Sangchul Lim),안태국(Teakook Ahn),남연우(Younwoo Nam),박선호(Sunho Park) 한국연소학회 2015 KOSCOSYMPOSIUM논문집 Vol.2015 No.12
Soot particles of diesel and bunker-A with different sulfur contents were generated by pyrolysis with varying conditions of fuel flow rate and residence time in the ceramic tube at 1300 oC. TEM and particle size analyzer were used for analysing the primary and the secondary particle size distributions. The results showed that the sulfur content in fuel influences soot inception while the fuel concentration and residence time affects the growth of incepted soot particles.
용액성장법(Solution growyth technique)에 의한 ZnS nano 입자 박막성장 및 구조적, 광학적 특성
이종원,임상철,곽만석,박인용,김선태,최용대 대전산업대학교 반도체기술연구소 2000 半導體技術硏究所報 Vol.2 No.-
본 연구에서는 청색 발광다이오드, 광전모듈레이터, 태양전지의 창문층 등의 광범위한 응용분야를 갖는 ZnS를 용액 성장법에 의해 nanometer 사이즈의 입자로 구성된 박막의 형태로 슬라이드 유리기판에 성정하고 구조적, 광학적 특성을 분석하고, 이 결과를 토대로 ZnS 박막의 양자사이즈효과에 대해 연구하였다. 성장조건에 관련된 인자는 precursor 용액의 농도, 성장온도, 암모니아 용액의 농도, 성장시간 등이었다. X-선 회절분석 결과, 본 연구에서 용액성장법으로 성정한 ZnS 박막은 cubic 구조(B-ZnS)를 가졌다. 성장온도가 75℃일 때 막의 표면상태가 가장 양호했으며 입자사이즈의 균일도도 가장 우수했다. 광에너지 변화에 따른 광투과도 측정 결과, 본 연구의 ZnS 시료는 성장조건을 조절함에 따라 에너지밴드갭이 3.69eV to 3.91eV까지 조절할 수 있었고, 이는 벌크 ZnS의 에너지밴드갭인 3.65eV보다 훨씬 높은 수치로서 양자사이즈효과에 의한 blue-shift 현상이 용액성장법으로 합성된 ZnS에서 큰 폭으로 나타남을 알 수 있었다. 그리고 Photoluminesence(PL) 측정 결과 ZnS 입자의 미세성으로 인한 입자 표면주위의 영향으로 PL 피크가 에너지밴드갭보다 훨씬 적은 에너지 영여겡서 발생했다. 특히 PL피크의 위치가 입자사이즈와 막두께에 따라 shift했는데, 이는 용액성장법으로 성장한 ZnS의 경우 본 연구에서 최초로 보고되는 것이다. In this study, the ZnS nanosized thin films that could be used for fabrication of blue light-emitting diodes, electro-optic modulators, and n-window layers of solar cells were grown by the solution growth technique (SGT), and their structural and optical properties were examined. Based on these results, the quantum size effects of ZnS were systematically investigated. Governing factors related to the growth condition were the concentration of precursor solution, growth temperature, concentration of aq.ammonia, and growth duration. X-ray diffraction patterns showed that the ZnS this film obtained in this study had the cubic structure (B-ZnS). When the growth temperature was 75℃, the surface morphology and the grain size uniformity were the best. The enerby band gaps of samples were determined from the optical transmittance valued, and were shown to vary from 3.69eV to 3.91eV. These values were substantially higher than 3.65eV of bulk ZnS, demonstrating that the quantum size effect of SGT grown ZnS is remarkable. Photoluminesence (PL) peaks were observed at the positions corresponding to the lower energy than that to energy band gap, illustrating that the surface states were induced by the ultra-fineness of grains in ZnS films. Particularly, for the first tiem, it is reported for the SGT grown ZnS that the PL peaks were shifted depending of the grain size.