• Title/Summary/Keyword: Scattering Ray

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Numerical Analysis of Back Scattering from a Target over a Random Rough Surface Using DRTM

  • Yoon, Kwang-Yeol
    • Journal of electromagnetic engineering and science
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    • v.10 no.2
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    • pp.61-66
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    • 2010

  • This paper is concerned with an analysis of the back scattering of electromagnetic waves from a target moving along random rough surfaces such as the desert, and sea. First, the discrete ray tracing method(DRTM) is introduced, and then, this method is applied to the back scattering problem in order to investigate the effect of the back scattering from random rough surfaces on the electric field intensities. Finally, numerical examples of various height deviations of the Gaussian type of rough surfaces are shown. It is numerically demonstrated that the back scattering is dominated by the diffractions related to the reflections from the random rough surfaces.

  • https://doi.org/10.5515/JKIEES.2010.10.2.061 인용 PDF KSCI

Small Angle X-ray Scattering Studies on Deformation Behavior of Rubber Toughened Polycarbonate (소각 X-선 산란을 이용한 고무입자로 강인화된 폴리카보네이트의 변형에 관한 연구)

  • Cho, Kilwon;Choi, Jaeseung;Yang, Jaeho;Kang, Byoung Il
    • Journal of Adhesion and Interface
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    • v.3 no.4
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    • pp.19-26
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    • 2002

  • In order to study the toughening mechanism of rubber modified polycarbonate, the sequence of development of micro-voids was investigated by real-time small angle X-ray scattering with Synchrotron radiation (SR-SAXS). The used test method was wedge test. The scattering intensity increases with increasing penetration depth of wedge, i.e. applied strain. The increase is due to the micro-void formation during deformation. This micro-void was uniformly developed in matrix and was different from large-void due to internal cavitation of rubber particle and/or debonding between rubber particle and polycarbonate matrix. The micro-void was developed at the critical strain and the radius of micro-void is around $600{\AA}$. Above the critical strain the size of micro-void remains almost constant with increasing applied strain. However, the population of micro-void increased with applied strain.

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TWO POSSIBLE COSMIC X-RAY SPECTRAL LINES

  • WU XUEJUN;Xu CHONGMING
    • Journal of The Korean Astronomical Society
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    • v.29 no.spc1
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    • pp.41-42
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    • 1996

  • A possible cosmic X-ray background(XRB) radiation related to original antimatter is considered. If the universe is made of separating domains of antimatter and matter, the photons produced by the annihilation of electron-positron and proton-antiproton on the last scattering surface would reach us in the energy $\~$0.45 keV and $\~$60 keV respectively because of the redshift. The spectrums of X-ray radiation from annihilation are deduced and a possible observational figure is described also.

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Mid Frequency Band Reverberation Model Development Using Ray Theory and Comparison with Experimental Data (음선 기반 중주파수 대역 잔향음 모델 개발 및 실측 데이터 비교)

  • Chu, Young-Min;Seong, Woo-Jae;Yang, In-Sik;Oh, Won-Tchon
    • The Journal of the Acoustical Society of Korea
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    • v.28 no.8
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    • pp.740-754
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    • 2009

  • Sound in the ocean is scattered by inhomogeneities of many different kinds, such as the sea surface, the sea bottom, or the randomly distributed bubble layer and school of fish. The total sum of the scattered signals from these scatterers is called reverberation. In order to simulate the reverberation signal precisely, combination of a propagation model with proper scattering models, corresponding to each scattering mechanism, is required. In this article, we develop a reverberation model based on the ray theory easily combined with the existing scattering models. Developed reverberation model uses (1) Chapman-Harris empirical formula and APL-UW model/SSA model for the sea surface scattering. For the sea bottom scattering, it uses (2) Lambert's law and APL-UW model/SSA model. To verify our developed reverberation model, we compare our results with those in Ellis' article and 2006 reverberation workshop. This verified reverberation model SNURM is used to simulate reverberation signal for the neighboring seas of South Korea at mid frequency and the results from model are compared with experimental data in time domain. Through comparison between experiment data and model results, the features of reverberation signal dependent on environment of each sea is investigated and this analysis leads us to select an appropriate scattering function for each area of interest.

  • https://doi.org/10.7776/ASK.2009.28.8.740 인용 PDF KSCI