Diffraction Physics Studies on QuasicrystaÕs

提出了各种X射线衍射研究，以提高 我们对准晶结构的了解 多重布拉格 散射将用于测量结构因子的相位， 特别是，要解决的问题是， 准晶具有反转中心。 提出要 用同步辐射高能束测量布拉格反射光强 x射线，为了避免消光和吸收 问题 绝对测量将通过测量 康普顿散射。 动态衍射的可能性 准晶体的影响将被探讨。 驻波 实验的目的是获得一些知识 各种原子在真实的空间中的相互位置 飞机。 拟议研究的总体目的是提供 实验信息有助于确定原子 Al-Cu-Fe准晶和Al-Pd-Mn准晶中的位。 %%% 准晶是一种金属合金，具有许多性质， 与普通晶体相同，但它们的对称性 不符合晶体学定律。 这个目标 建议是确定原子位置。 除了他们对基础科学的兴趣之外， 其卓越的抗氧化性、耐高温性和 碱性腐蚀使其成为令人感兴趣的新材料。

A variety of x-ray diffraction studies are proposed for improving our knowledge of the structures of quasicrystals. Multiple Bragg scattering will be used to measure phases of structure factors, and, in particular, to address the question whether or not certain quasicrystals have a center of inversion. It is proposed to measure intensity of Bragg reflection using synchrotron high energy x-rays, in order to circumvent the extinction and the absorption problems. Absolute measurements will be performed by measuring Compton scattering. The possibility for dynamical diffraction effects in quasicrystals will be explored. Standing waves experiments are proposed for the purpose of gaining some knowledge about the reciprocal positions in real space of the various atomic planes. The general purpose of the proposed research is to provide experimental information useful for a determination of the atomic sites in Al-Cu-Fe and Al-Pd-Mn quasicrystals. %%% Quasicrystals are metallic alloys that have many properties in common with ordinary crystals, yet their symmetry properties are not compatible with the laws of crystallography. The goal of this proposal is to determine the locations of the atomic sites. Besides their interest from the point of view of basic science, their exceptional resistance to oxidation, high temperature and alkaline corrosion makes then interesting as new materials.