摘要(英) |
Abstract
X-ray diffraction is a very powerful tool for structural analysis, from which information on composition, structure, and particle size may be obtained. The aim of this thesis is to determine the particle size distribution function (PSD) of powder samples consist of ultra small nano-particles employing the Fourier analysis to the diffraction profiles. We related the powder diffraction line profile to the particles size distribution through the common volume function and the column length distribution function. We followed the idea introduced by E. F. Bertaut in 1950, but using an analytic function to account for the statistical fluctuations which is intrinsic to the experimental data. Assuming that the common volume function us analytic, the line profile function and the corresponding particle size distribution may then be obtained.
The nano-particle powders were synthesized by the gas condensation method. These samples have a common feature: the line profiles are far from Gaussian and exhibit a narrow tip with wide spread wings. We concluded that such deviation from Gaussian type can be explained to be due to the highly dispersion of the particle size distribution. In order to account for high degree of dispersion, two distributions of different widths and heights were allowed in the analysis. By considering such criteria, very good fitting to the powder patterns can generally be obtained. |
參考文獻 |
參考文獻
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