• Title/Summary/Keyword: Sattering

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A study of integral equations for the analysis of scattered acoustic field (산란음장 해석을 위한 적분방정식에 대한 연구)

  • Wonju Jeon;Lee, Duck-Joo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1016-1019
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    • 2002
  • This paper deals with a fundamental and classical scattering problem by a finite strip. For the analysis of scattered acoustic field, a “single” integral equation is derived. Firstly, the complexity by considering the effect of the mean flow is alleviated by the introduction of Prandtl-Glauert coordinate and the new dependent variable. Secondly, the difficulty of solving the resultant strongly-coupled integral equations which always appear in this kind of 3-part mixed boundary value problem is solved by observing some good properties of the functions in complex domain and manipulating the equations and variables for the use of those properties. The solution can be obtained asymptotically in terms of gamma function and Whittaker function. One aim of this study is the improvement of methodology for the research using integral equations. The other is the basic understanding of scattering by a finite strip related to the linear cascade model of rotating fan blades.

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The study of artificially soft and hard surfaces using periodic strips loaded with two layered dielectric slabs over a ground plane (접지판 위에 두개의 유전체 층을 갖는 주기적인 스트립 격자 구조에서의 소프트 및 하드표면 연구)

  • Ko, J.H.;Kang, S.C.;Kim, J.M.;Cho, Y.K.;Son, H.
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.10
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    • pp.71-80
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    • 1996
  • Sattering problem of electromagnetic waves by periodic strip grating with two dielectrics over a ground plane in case of oblique incidence and arbitrary polarization is analyzed by the vector floquet mode expansion method and the moment mehtod from the viewpoint of soft and hard boundary value problem. To confirm proposed analysis methods, we examine the solution convergence for the scattering problem. And some numerical results of artificially soft and hard surfaces using the structure filled with single dielectric slab between periodic strip grating and gorund plane is compared with previous results. Some interesting results for soft and hard surfaces using periodic strips loaded with two layered dielectric slabs over a ground plane are given.

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Synthesis of Titanium Dioxide Nanoparticles with a High Crystalline Characteristics (높은 결정성을 갖는 이산화티탄 나노입자의 합성)

  • Kim, Ki-Chul
    • Journal of Convergence for Information Technology
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    • v.7 no.5
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    • pp.53-58
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    • 2017
  • In the age of oil exhaustion, low cost, semi-transparent solar cell, the dye-sensitized solar cell (DSC) has attracted significant attention since 1991 of $Gr{\ddot{a}}tzel$ report. To enhance the light-harvest capability of the photoelectric electrode, and efficiency of photoelectric transformation of the DSC, scattering layer of various structure have been proposed to photoelectric electrode materials. The scattering center of scattering layer needs the large titanium dioxide nanoparticles of 250 - 300 nm in diameter. In this study, the large sized $TiO_2$ nanocyrstals of around 300 nm were synthesized using the modified sol-gel process. According to the analysis of XRD and TEM, the synthesized $TiO_2$ nanoparticles exhibit single crystals of anatase phase. The optical transmittance of the synthesized titanium dioxide film prepared by spin coating is around 50% at 550 nm. It is suitable for scattering layer as a scattering center, and expected to enhance the efficiency of photoelectric transformation of the DSC.