• Title/Summary/Keyword: X-RAY SCATTERING

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Studies on Transparently Crystallized Glass -On Li2O-Al2O3-SiO2 Composition- (투명 결정화 유리에 관한 연구 -Li2O-Al2O3-SiO2계 조성에 관하여-)

  • 박용완;김건은;연석주;조중희
    • Journal of the Korean Ceramic Society
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    • v.26 no.3
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    • pp.315-322
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    • 1989

  • Li2O-Al2O3-SiO2 system glasses contained P2O5, TiO2 and ZrO2as the nucleating agents were melted and formed. The glass was subsequently heated first to nucleate and then to grow the crystals. At constant nucleating agent content the base glass compositions were varied and the influences of these variations on the crystallization behaviour were investigated. The study was made by measurement of thermal expansion coefficient, differential thermal analysis, X-ray diffraction analysis, scanning electron microscope observation and transmission measurement of crystallized glass specimen in visible region. It was shown that the content of crystalline phase decreased with increasing SiO2 content as well as decresing Li2O in the base glass compositions. As the result of X-ray diffrection analysis, the major crystal was $\beta$-quartz solid solution. The degree of crystallinity which was calculated using the noncrystalline scattering methods increased in S-shape with increasing heat treatment time. This change was similar to that in thermal expansion coefficient. The transmissions of 5mm thick samples were 80-90% in visible ray region.

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Development of Radiation Shielding Analysis Program Using Discrete Elements Method in X-Y Geometry (2차원 직각좌표계에서 DEM을 이용한 방사선차폐해석 프로그램개발)

  • Park, Ho-Sin;Kim, Jong-Kyung
    • Nuclear Engineering and Technology
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    • v.25 no.1
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    • pp.51-62
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    • 1993

  • A computational program ［TDET］ of the particle transport equation is developed on radiation shielding problem in two-dimensional cartesian geometry based on the discrete element method. Not like the ordinary discrete ordinates method, the quadrature set of angles is not fixed but steered by the spatially dependent angular fluxes. The angular dependence of the scattering source term in the particle transport equation is described by series expansion in spherical harmonics, and the energy dependence of the particles is considered as well. Three different benchmark tests are made for verification of TDET : For the ray effect analysis on a square absorber with a flat isotropic source, the results of TDET calculation are quite well conformed to those of MORSE-CG calculation while TDET ameliorates the ray effect more effectively than S$_{N}$ calculation. In the analysis of the streaming leakage through a narrow vacuum duct in a shield, TDET shows conspicuous and remarkable results of streaming leakage through the duct as well as MORSE-CG does, and quite better than S$_{N}$ calculation. In a realistic reactor shielding situation which treats in two cases of the isotropic scattering and of linearly anisotropic scattering with two groups of energy, TDET calculations show local ray effect between neighboring meshes compared with S$_{N}$ calculations in which the ray effect extends broadly over several meshes.eshes.

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