• Title/Summary/Keyword: Optical and chemical properties

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A Study on Spectra of Laser Induced Fluorescence in Phantom (Phantom에서 Laser Induced Fluorescence의 스펙트라에 관한 연구)

  • Kim, Ki-Jun;Sung, Ki-Chun
    • Journal of the Korean Applied Science and Technology
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    • v.16 no.4
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    • pp.329-335
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    • 1999
  • The influences of fluorophor, scatterer, and absorber in turbid material by light scattering were interpreted for the scattered fluorescence intensity and wavelength. The molecular properties have been studied by laser induced fluorescence spectroscopy in phantom. It has been found that the effects of optical properties in scattering media could be investigated by the optical parameters(${\mu}_a$, ${\mu}_a$, ${\mu}_t$). Experimental and Monte Carlo Simulation method for modelling light transport in tissue was applied. The experimental results using a phantom were discussed and compared with those obtained through Monte Carlo Simulation. It may also aid in designing the best model for oil chemistry, medicine and application of medical engineering.

Collective Electronic Oscillator Method: Application to Conjugated Organic Molecules

  • Lee, Jin-Yong
    • Bulletin of the Korean Chemical Society
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    • v.24 no.6
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    • pp.780-784
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    • 2003
  • The collective electronic oscillator (CEO) method was developed by Mukamel and collaborators.[Phys. Rev. Lett. 1992, 69, 65; Science 1997, 277, 781] Recently Ⅰ have extended the CEO method to obtain the frequency dependent optical properties with all the contributing components. The brief introduction of the CEO fomalism and its recent applications to linear absorption and two-photon absorption (TPA) of conjugated organic molecules will be discussed. The size scaling of optical properties of polyenes and polyynes have studied by ab initio calculations, and this result is consistent with the coherence length of the time dependent densities to first ($ρ^(1)$) and second order ($ρ^(2)$) in the electric field obtained from the CEO method.

Properties of CdS Thin Films Prepared by Chemical Bath Deposition as a Function of Thiourea/CdAc2 Ratio in Solution (CBD법으로 제작된 CdS 박막의 thiourea/CdAc2 농도비에 따른 특성)

  • Song, Woo-Chang
    • Journal of the Korean institute of surface engineering
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    • v.41 no.1
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    • pp.28-32
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    • 2008
  • In this paper CdS thin films, which were widely used window layer of the CdS/CdTe and the CdS/$CuInSe_2$ heterojunction solar cell, were grown by chemical bath deposition, which is a very attractive method for low-cost and large-area solar cells, and the structural, optical and electrical properties of the films was studied. As the thiourea/$CdAc_2$ mole ratio was increased, the deposition rate of CdS films prepared by CBD was increased due to increasing reaction velocity in solution and the optical bandgap was increased at higher thiourea/$CdAc_2$ mole ratio due to larger grain size and continuous microstructure. The minimum resistivity of the films was at thiourea/$CdAc_2$ mole ratio of 3.

Optical Properties and Structure of Black Cobalt Solar Selective Coatings (흑색 코발트 태양 선택흡수막의 광학적특성과 구조)

  • Lee, Kil-Don
    • Journal of the Korean Solar Energy Society
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    • v.31 no.4
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    • pp.48-56
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    • 2011
  • Black cobalt solar selective coatings were prepared by thermal oxidation of electroplated cobalt metal on copper and nickel substrates. The optical properties and structure of the black cobalt selective coating for solar energy utilizations were characterized by glow discharge spectrometry (GDS), ultraviolet-visible-near infrared (UV-VIS-NIR) spectrometer, atom force microscopy(AFM) and X-ray photoelectron spectroscopy(XPS). The optical properties of optimum black cobalt selective coating prepared on copper substrate were a solar absorptance of 0.82 and a thermal emittance of 0.01. From the GDS depth profile analysis of these coatings, the concentration of cobalt particles near the interface was higher than at the surface, but oxygen concentration at the surface was higher than at the interface. These results suggest that the selective absorption was dominated by this chemical composition variation in the coating. The surface of this film exhibited morphology with root-mean-square(rms) roughness of about 144.3nm. XPS measurements data showed that several phases of Co coexist($Co_3O_4$,CoO) in the film.