Studies on imperfection and phase transformation in crystalline minerals

晶体矿物中的缺陷和相变的研究始于1995年，并一直持续至今。本课题的主要内容是：（1）研制一套漫散射分析系统;（2）为我们的衍射系统配备单色器和新的探测器，以指导系统适用于漫散射测量;（3）对某些材料的漫散射进行测量并对测量数据进行分析。迄今为止取得的成果和正在进行的研究如下。关于第一个主题，德国汉诺威大学的Rahman教授建议我们相互合作，分析我们这几年所研究的镁黄长石群衍射图案中发现的漫散射。拉赫曼教授开发了一个强大的系统，用计算机模拟和重建漫散射，并希望使他的系统适应我们的问题。1996年，我们开始合作， ...更多信息 使该系统适用于分析无公度结构，然后模拟在镁黄长石族矿物的衍射图案中观察到的漫散射。本研究的研究者之一仍在汉诺威大学从事这些问题的研究。关于第二个课题，我们已经构建了一个测量漫散射的系统。晶体单色器（石墨和Si）安装在高功率X射线发生器（12 kW）上，并新开发了配备“成像板”暗盒的Weissenberg相机。在第三个课题中，我们确定了镁黄长石[Ca_2MgSi_2O_7]和镁黄长石固溶体[Ca_2（Mg，Fe）Si_2O_7]在五维空间中的无公度结构。一篇关于后者的无公度结构的晶体化学讨论的论文已提交给一家杂志。漫散射的模拟结果提交给了1997年在汉堡举行的德国晶体学协会年会。由于镁黄长石固溶体样品在显微镜下含有不同延迟的畴，我们用同步辐射测量了不同畴的漫散射，并进行了分析。我们还利用分子轨道方法对漫散射进行了模拟，以阐明无公度调制的起源，并得到了初步的结果。关于铝和铁的氢氧化物的脱水产物，我们的研究者正在汉诺威大学进行漫散射分析。少

The research on imperfection and phase transformation in crystalline minerals started in 1995 and has been undertaken ever since. The subjects of the research are (1) to prepare a system for analyzes of diffuse scattering, (2) to equip our diffraction system with monochromators and new detect in order to direct the system suitable for measurements of diffuse scattering, and (3) to measure diffuse scattering of some materials and to analyze the measured data. The results obtained up to the present and the research being in progress are as follows.On the first subject, prof.Rahman of the university of Hannover, Germany, proposed us to collaborate with each other on analyzes of the diffuse scattering found in diffraction patterns of akermanite group on which we have worked in these several years. Prof.Rahman had developed a powerful system to simulate and reconstruct diffuse scattering by computers and wanted to adapt his system to our problems. In 1996 we have started our collaboration t … More o adapt the system for analyzes of incommensurate structures and then to simulate diffuse scattering observed in the diffraction patters of akermanite group minerals. One of the investigators of this research is still working in the University of Hanover on these problems.On the second subject, we have constructed a system to measure diffuse scattering. Crystal monchromators (graphite and Si) were installed on a high-power X-ray generator (12kW) and a Weissenberg camera equipped with a cassette for'Imaging plate' was newly developed. The system is working for measurement of diffuse scattering now.On the third subject, we have determined the incommensurate structures of akermanite [Ca_2MgSi_2O_7] and of akermanite solid solution [Ca_2 (Mg, Fe) Si_2O_7] with the description in five-dimensional space. A paper of a crystal-chemical discussion of the incommensurate structure of the latter has been submitted to a journal. Results of the simulation of the diffuse scattering was presented to the annual meeting of German Crystallographic Association in 1997 at Hamburg. Since samples of akermanite solid solution include some domains with different retardation under a microscope, we measured diffuse scatterings from different domains with synchrotron radiation and we are analysing them now. We are also making simulation of the diffuse scattering by a molecular orbital method in order to clarify the origin of the incommensurate modulation, and we could get preliminary results. On dehydration products of hydro-oxides of Al and Fe, our investigator is analysing the diffuse scattering at the University of Hannover now. Less