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利用同步辐射x射线衍射和 DAC 高压技术在室温下测量了钙钛矿CaTiO3在压力0—44.53 GPa下的结构变化.结果表明,随着压力的增加CaTiO3的三个晶轴都受到不同程度的压缩,a,b的压缩率相近且相对比较大,c的压缩率最小,但没有证据表明有相变的发生.在压力范围内CaTiO3的P-V关系用Murnaghan状态方程表示,设定K′0=4,得到V0=0.2245(6)nm3和K0=222(9) GPa.应用赝立方角γpc与压力的关系,初
关键词:
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结构
超高压
状态方程 相似文献
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钩端螺旋体去甲酰化酶(Leptospira interrogans PDF)是一种重要的含锌金属蛋白酶, 对钩端螺旋体这一广泛存在的致病菌的蛋白合成起着关键的催化作用, 是一个很好的药物设计靶蛋白. 本文测试了LiPDF在pH3.0的溶液状态下的X射线吸收近边结构(XANES: X-Ray Absorption Near-Edge Structure)谱, 利用以从头计算(ab. initio)的多重散射(Multiple Scattering)为基础的MXAN方法确定金属蛋白活性中心的精细结构. 研究发现结合合适的初始结构模型, 可以更好地重现LiPDF蛋白的XANES曲线, 从而能够得到更加准确的结构参数. 活性中心的精细结构为理解LiPDF的pH依赖的催化活性提供了结构基础. 相似文献
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With the development of the XFEL (X-ray free electron laser), high quality diffraction patterns from nanocrystals have been achieved. The nanocrystals with different sizes and random orientations are injected to the XFEL beams and the diffraction patterns can be obtained by the so-called "diffraction-and-destruction" mode. The recovery of orientations is one of the most critical steps in reconstructing the 3D structure of nanocrystals. There is already an approach to solve the orientation problem by using the automated indexing software in crystallography. However, this method cannot distinguish the twin orientations in the cases of the symmetries of Bravais lattices higher than the point groups. Here we propose a new method to solve this problem. The shape transforms of nanocrystals can be determined from all of the intensities around the diffraction spots, and then Fourier transformation of a single crystal cell is obtained. The actual orientations of the patterns can be solved by comparing the values of the Fourier transformations of the crystal cell on the intersections of all patterns. This so-called "multiple-common-line" method can distinguish the twin orientations in the XFEL diffraction patterns successfully. 相似文献
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In this paper the solution conformation of the response regulator proteins from Deinococcus radiodurans was studied by small-angle X-ray scattering (SAXS). The SAXS curves of Dr-rrA in solutions were obtained at Beamline 1W2A of Beijing Synchrotron Radiation Facility (BSRF). Two possible conformations of the response regulator proteins, compact and incompact conformations, have been represented by the known crystallographic structures. And theoretical solution scattering curves of the two possible conformations were calculated and fitted to the experimental scattering curve of Dr-rrA, respectively. The result indicates that the solution conformation of the response regulator proteins is inclined to the compact one, which is in agreement with the result of biochemical experiments. 相似文献
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对于组份为x=0.0和x=0.3的巨磁电阻锰氧化物Pr1-x Srx MnO3(PSMO)体系在OK阈值,Mn L2,3边的区域内进行了O1s2p2p俄歇谱随光子能量变化的实验研究.实验结果显示O1s2p2p俄歇峰发生分裂并且可将其拟合为3个子峰.PSMO在OK阈值或Mn L2,3边以下进行激发时,其俄歇峰3个子峰的相对强度基本保持恒定,然而反映终态效应特性的总强度却有起伏发生.这一状况在Mn L2,3边以上激发时表现更为显著,即组份为x=0.3的总强度为x=0.0的4倍.对这些现象在共价键图 相似文献
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Investigation of the topological shape of bovine serum albumin in solution by small-angle x-ray scattering at Beijing synchrotron radiation facility 下载免费PDF全文
This paper reports that at a newly constructed small-angle x-ray scattering station of Beijing Synchrotron Radia- tion Facility, the topological shape of ligand-free bovine serum albumin in solution has been investigated. An appropriate scattering curve is obtained and the calculated value of the gyration radius is 31.2~=t=0.25 ~_ (11=0.1 nm) which is co- incident with other ones' results. It finds that the low-resolution structure models obtained by making use of ab initio reconstruction methods are fitting the crystal structure of human serum albumin very well. All of these results perform the potential of the beamline to apply to structural biology studies. The characteristics, the defects, and the improving measures of the station in future are also discussed. 相似文献
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<正>20世纪后半叶发展最迅速的一个学科是结构生物学,这是一门通过蛋白质结构来诠释蛋白质功能的学科,DNA双螺旋结构和血红蛋白以及肌红蛋白的结构的确定标志着这个学科的建立。蛋白质是生命活动主要的执行者,只有形成了正确的结构,蛋白质才能具有正确的功能。因此蛋白质的结构研究,不仅可以让我们得以深入了解生物体内诸多生命过程的细节,更有助于重大疾病的预防和治疗、新型高效药物和疫苗 相似文献