闪光X射线衍射成像系统设计及实验方法

为实现材料在冲击加载下微观动力学响应测量,基于小型闪光X射线源开展衍射成像系统设计.利用直流X光机及高纯锗探测器实现系统衍射光路的精确调节,克服了闪光X射线瞬时强度高及连续辐射本底强导致的衍射角度确定困难,并采用Scandiflash AB公司TD-450S和成像板建立了衍射成像系统.应用该系统在冲击加载实验中获得了LiF单晶单脉冲的Mo-Kα线静态及动态衍射图像.该闪光X射线衍射系统时间分辨率可达25ns,为冲击压缩实验中材料瞬时结构变化测量提供了新的实验方法.     

Co2+-L-赖氨酸的合成及其X射线光谱研究

本文以氯化钴和Ｌ－赖氨酸为原料,合成了Ｃｌ＾２＋－Ｌ＝赖氨酸配合物,对配合物进行了钴含量的测定,并且观测了配合物的Ｘ射线光谱,确定了钴离子与Ｌ－赖氨酸的配位形式。     

复色光源X射线光栅衍射效率

基于Fresnel衍射理论,分析了复色光源X射线光栅衍射效率.研究了X射线光栅不同材料、不同槽深、源的谱分布及不同占空比对衍射效率及成像质量的影响,给出这些参量的选择方法.主要考虑了各种参量对光栅0级及1级衍射强度的影响.发现高Z元素的物质不适合做X射线光栅材料,低Z元素Be、Si、Al及有机物PMMA等较适合18~30 keV波段的X射线光栅.源的谱分布决定了光栅槽深选择.数值计算给出了Si光栅各种参量的具体值.     

矿物中药钟乳石的X射线衍射Fourier指纹图谱

研究矿物中药钟乳石X射线衍射Fourier指纹图谱.对10批主产地的钟乳石药材X射线衍射Fourier图谱进行分析,建立钟乳石X射线衍射Fourier指纹图谱,并通过相似度计算,区分钟乳石、其他含钙矿物中药、同种化学试剂CaCO3.主成分相同的矿物中药利用X射线衍射Fourier指纹图谱无法完全区分,但钟乳石与同种化学试剂CaCO3的X射线衍射Fourier图谱区别显著.利用X射线衍射Fourier指纹图谱可以很好的区分含有不同化学成分的矿物药,而对于主成分相同的矿物中药,就不能简单地利用它们的X射线衍射Fourier指纹图谱加以区分,即X射线衍射Fourier指纹图谱仅具有相对的专属性.     

X-ray Diffraction Study on Pressure-Induced Phase Transformation in Nanocrystalline GaAs

We have shown that the onset and transition pressures of the GaAs I M II transition are 17 GPa and 20 GPa, respectively, for both bulk and nanophase material. The observed gradual change in resistivity of nanophase GaAs at the semiconductor-to-metal transition is explained by the two-component model developed by Gleiter.     

海洛因的X射线衍射谱

本文给出海洛因和鸦片的实测Ｘ射线衍射谱;并且列出海洛因的每一个衍射峰参数。海洛因属于正交晶系;原胞基矢是：ａ＝８．００３,ｂ＝１４．３７３,ｃ＝１６．０９２×１０－１０ｍ。对比纯净的海洛因和蔗糖的标准谱,我们检查出主要的掺杂物是糖。     

基于光栅衍射的晶体X射线衍射缺级的理论基础和实验研究

以光栅衍射缺级理论为切入点对晶体X射线衍射缺级的现象、产生的根源进行了理论分析,得出：(1) 晶体X射线衍射缺级存在的可能性在于某些晶体材料晶胞的几何结构因子为零;(2) 在复式格子晶体或具有某种特殊缺陷的晶体的X射线衍射图样中存在缺级是这方面实验研究的方向。这些结论在材料物相、材料结构类型和不完整性分析等方面具有一定的参考价值。     

X射线衍射法测定液态纯铁的密度

用X射线衍法测试了液态纯铁在1550℃的质量密度，并与文献中的实验结果进行了比较。结果发现，本文计算的密度6．971g/cm^3与文献中的实验结果7．0g/cm^3非常接近，说明本文的计算方法准确、可行。     

Bi3+-Cys配合物的X射线粉末衍射光谱

本文研究了金属铋离子与胱氨酸配合物的合成方法，采用X射线粉末衍射光谱对配合物进行了分析鉴定，结果表明，Bi^3 能与Cys形成配合物。     

X-ray Diffraction Study of Cd 0.8 Zn 0.2 Te Under High Pressure and Temperature

Energy dispersive X-ray diffraction using synchrotron radiation has been used to study phase transformations of Cd 0.8 Zn 0.2 Te under high pressure and temperature. We confirm the presence of a cinnabar phase between the zinc-blende and rock-salt phases. But contrary to the results in CdTe, this intermediate phase is found to be stable only on pressure decrease and in a narrower pressure and temperature range. Single-phase cinnabar patterns are obtained only at 300 and 373 K. At 673 K and above, even on pressure decrease, no evidence of the cinnabar phase is found. In this temperature range, a phase segregation phenomenon is observed in the zinc-blende phase during the zinc-blende transition in both upstroke and downstroke, and the retrieved sample at ambient conditions presents a double pattern corresponding to two different Zn contents.     

单缝衍射图像的仿真与研究

应用M atlab编程仿真单缝衍射形成的图像及全息图,数值模拟了夫琅禾费衍射和费聂耳衍射的衍射图和全息图,分析比较了它们的区别和联系,研究结果为电磁波发射中天线的探测提供理论依据。     

High Pressure X-Ray Absorption and Diffraction Study of InAs

We have performed X-ray absorption (XAS) and diffraction (XRD) measurements at high pressure on samples of powdered InAs, up to 50 and 80 GPa, respectively. In the lower pressure range, our data are consistent with the following structural sequence: Zincblende M NaCl M Cmcm . The first order transition from the semiconducting Zincblende phase to the metallic NaCl phase is clearly seen by the shift in the absorption onset at the As K-edge and the strong modifications of the extended X-ray absorption fine structure (EXAFS) due to the changes in the local structure from a 4-fold to a 6-fold coordinated environment. XAS shows the high pressure phase to be locally site-ordered. The diffraction data, analized by Rietveld fitting, gives a volume discontinuity of j V/V 0 ～0.18 for the first order transition. There is no apparent volume discontinuity associated to the NaCl M Cmcm transition.     

利用X射线衍射光谱研究丝织品的老化

中国考古出土的丝织品数量大,种类丰富,是中国古代文化遗产的重要组成部分,但由于丝蛋白易于降解老化的材料特性,有许多保护问题需要研究解决。对古代丝织品老化程度、老化特征的分析检测有助于了解丝织品的保存状况,并可为保护方法的选择与改进提供帮助。文章通过X射线衍射分析对丝织品老化特征及结晶度的变化进行了研究。样品为经光老化、热老化和水解老化的白色丝织品和出土于湖北、陕西、内蒙古、青海的古代丝织品。X射线衍射分析结果表明,X射线衍射分析可以揭示丝织品的老化作用过程和老化特征,以及相应结晶度的变化,对于出土古代丝织品保存状况及老化机理的研究来说具有实用价值。同时还可为了解古代染织工艺的发展提供信息。     

H2SO4-HAc-GIC的合成及其X射线衍射光谱和紫外光谱研究

本文以天然鳞片石墨为原料,合成了H2SO4－HAc-GIC,对该石墨层间化合物进行了X衍射及紫外光谱分析,测定了含硫量,并利用光谱分析结果对反应机理进行了初步探讨。     

X-Ray Diffraction Investigation of Oleic Acid under High Pressure

Pressure has a specific influence on the light scattering in those liquids in which all molecules have an unsaturated double bond C=C. Strong changes of intensity of transmitted and scattered light in oleic acid were observed during its transition to the high-pressure phase. In this paper, local order in liquid of oleic acid has been studied using the X-ray diffraction photographic Laue method. Experiments were run at room temperature under atmospheric pressure as well as under pressures up to 0.25 GPa. At pressures above 0.2 GPa a strong increase of ordering of molecules, similar to a smectic liquid crystal phase, has been observed. This confirms results obtained previously by studies of light scattering under high pressure.     

X射线光谱法研究Cd2+-氨基酸配合物

本文研究了重金属离子Cd^2 －Glu配合物的合成方法，用X射线光谱对Cd^2 －氨基酸配合物进行了鉴定。     

基于样条法的米兰X射线衍射二阶导数指纹图谱

利用3次样条法编写了由X射线衍射指纹图谱的二阶导数图谱的Matlab程序,利用该程序分别获得了标准样品SiO2和米兰的二阶导数指纹图谱,结果表明该方法能有效解决植物类药材弥散型X射线衍射指纹图谱解析问题,放大功能显著,值得推广.     

XRD技术在大学生科研训练计划中的应用

在大学生科研训练计划中,熟练的掌握一门实验技术至关重要。本文以XRD(X射线衍射技术)技术为例,介绍了物相分析的原理和方法,阐述了其在材料学本科生科研训练计划中的应用价值。有效的推进了大学生科研训练计划顺利开展,极大地激发了学生创新意识和创新思维。     

Application of X-ray Powder Diffraction to Nano-materials - Determination of the Atomic Structure of Nanocrystals with Relaxed and Strained Surfaces

The applicability of standard methods for the evaluation of powder diffraction data of nano-size crystallites is analyzed. Based on theoretical considerations, it is shown that deviations of the structure of small particles from the Bragg approximation on an infinite crystal lattice leads to significant differences in the diffraction patterns, which may lead to an erroneous interpretation of the experimental results. An alternative evaluation of the diffraction data of nano-particles, based on the so-called "apparent lattice parameter", alp , is proposed. Based on this method, it is shown that real nano-crystals constitute a complex, heterogeneous multi-phase structure.     

二元矩形软X射线衍射光栅的标量区衍射理论

利用标量区衍射理论分析了正交二元矩形软Ｘ射线衍射光栅的光学特性，给出了理论设计的初步结果。