原料药的晶型研究中粉末衍射峰强度问题？多谢，保证样品的取向随机性很重要，这个怎么考察，怎么检测？我们一般的样品都是过100目筛，做衍射图，这样操作能保证样品的取向随机性嘛？... "referential Orientation (or, is some cases, “Texture”) One of the basic assumptions of meaningful XRD is the homogeneous spatial and angular, distribution of the crystallite orientations in the different directions. Any deviation from homogeneity make sampling of intensities (the reproducibility of the measurement) rather difficult. Nevertheless, in a few cases, this effect is informative of the genesis and microstructure of the sample (deformed metal, geological sediments, rolling and cleavage, etc.). Elimination of preferred orientation effects (one of the most common experimental problems!) would not exist if the crystals were morphologically spherical. But the crystal world is intrinsically vectorial, not scalar, and anisotropy (structural and morphological) in the rule, not the exception! Preferred orientation, it not completely avoidable, must be reduced as much as possible, and later interpreted on the basis of cleavage properties or on the crystal structure (evidencing, whenever possible, sections with weak intermolecular contacts)." http://www2.arnes.si/~sgszmera1/html/xrd/preparation2.html查看更多
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