衍射花樣指數(shù)化與應(yīng)用概述(1)-wenkub
2023-05-21 10:28:58 本頁面
【正文】 not appreciably affect the power of trialanderror methods. However, 39。 測定衍射花樣三要素在不同狀態(tài)下的變化 ， 是衍射分析應(yīng)用的基礎(chǔ) 。 (3) 晶體 (相 )結(jié)構(gòu) ,磁結(jié)構(gòu) ,表面結(jié)構(gòu) ,界面結(jié)構(gòu)的研究 蘇 玉 長 衍射分析應(yīng)用 ? 同時基于衍射位置、強度和線型的Rietveld多晶結(jié)構(gòu)測定 需輸入原子參數(shù)（晶胞中各原子的坐標、占位幾率和濕度因子）、點陣參數(shù)、波長、偏正因子、吸收系數(shù)、擇優(yōu)取向參數(shù)等。 實際應(yīng)用中，將精確測得的點陣參數(shù)與已知數(shù)據(jù)比較即可求得固溶體的組分。因此，測得含量為 x的 B原子的因溶體的點陣參數(shù)工 ax，用上式即求得固溶體的組分。 蘇 玉 長 衍射分析應(yīng)用 ? 基于衍射強度測量的應(yīng)用 （ 1）物相的定量分析，結(jié)晶度的測定 (2) 平衡相圖的相界的測定； (3) 第三類應(yīng)力的測定； (4) 有序固溶體長程有序度的測定； (5) 多晶體材料中晶粒擇優(yōu)取向的極圖、反極圖和三維取向分布的測定； (6) 薄膜厚度的測定。 ( Ref.[4]). 蘇 玉 長 The standard procedure using TREOR is to start with the high symmetries: cubic, tetragonal, hexagonal and orthorhombic in one run. Next the monoclinic symmetry should be tried. More than one run may be necessary, successively increasing the number of baseline sets, the cell volume and cell edge. If the formula weight and density are known, they should be used. The CPUtime needed will then usually be strongly reduced. Unfortunately they are mostly not well known and therefore not often usable. If all previous tests have failed the triclinic test remains for which in general we remend ITO. 蘇 玉 長 Analytical Approach The crystal is assumed to be triclinic. Solutions are approached in three steps. In the first, one tries to find reasonable zones from the diffraction data. Each pair of lines, together with the origin forms a crystallographic zone. A zone is relevant to the solution finding algorithm if some other diffraction lines lie on it, if not it is discarded. In the second step the best zones are then tried in binations to find plete lattices. This method is known as the ITO method. Once a lattice is found that satisfies the experimental ds
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