Enhancing primary processing for small-angle X-ray scattering

A program is reported for primary processing of small-angle X-ray scattering from various cameras. The software integrates basic functions necessary for primary processing that include instrument parameter calibration, scattering angle calibration, the conversion of a two-dimensional image to a one-dimensional curve, background and absorption subtraction, and correction for collimation effects. All instrument parameters for primary processing needs were derived with high precision by fitting a diffraction ring of a standard without the measurement of other parameters. The program is applicable whether the detector photosensitive plane is vertical or tilted with respect to the direct beam and operates easily, automatically, and rapidly on Windows computers. This article describes the structure, function, and features of the software.     

Continuous flow time-resolved small-angle x-ray scattering and X-ray absorption spectroscopy

A continuous flow device to characterize the growth of nanometer particles was assembled. In-situ millisecond or second-order time-resolved small angle x-ray scattering and x-ray absorption spectroscopy was performed using this device at the Beijing Synchrotron Radiation Facility. The time resolution was adjusted from 10 ms to 1.0 s by changing the flow rate of the solution. The temperature was variable from 5–95°C. Custom-designed pulse eliminators were employed to eliminate adverse pump fluctuations and improve the quality of measurements. The system was used to characterize zinc sulfide nanoparticles by small angle x-ray scattering and x-ray absorption spectroscopy.     

新型X射线粉末衍射仪高级功能应用研究

本文介绍了德国布鲁克公司新一代的X射线粉末衍射仪"D8 ADVANCE with DAVINCI design"的光源、测角仪、光路系统、探测器和应用软件,并对该仪器进行功能开发应用研究。测试表征了介孔材料SBA-15的小角衍射,并与"NanoSTAR X射线小角散射系统"测试的结果进行对比;测试了3种纤维样品的取向度;通过X射线反射(XRR)测定多层膜,并使用Leptos软件进行了拟合,得到了各层膜的厚度、粗糙度及密度;通过测定单晶样品的摇摆曲线来确定单晶样品的晶面;最后简要介绍了对分布函数(Pair Distribution Functions(PDF))的测定及计算。通过对这些非常规的测试及表征,开发了该仪器的功能。     

光学表面X射线异常散射现象

研究了用掠入射散射法测量光学表面散射分布实验中存在的异常散射现象。首先,介绍了实验装置,并用原子力显微镜(AFM)测量了样品的表面粗糙度, 给出了工作波长为0.154 nm时不同样品在不同掠入射角下的表面散射分布。然后,分析了异常散射角与临界角的关系。最后,对影响散射强度的因素进行了分析。实验结果表明：当掠入射角大于临界角时能观测到光学表面的异常散射现象。在波长一定的情况下,异常散射角与样品材料有关,与掠入射角和表面粗糙度无关;异常散射角略小于临界角,误差变化为-8.6%~-0.9%。另外,镜像反射强度随着入射角和表面粗糙度的增大而迅速减弱,但异常散射强度与镜像反射强度的比值（峰值比）反而随着掠入射角或表面粗糙度的增大而增大,其比值在0.012~2.667变化。结果证明样品的材料和表面形貌是影响异常散射分布的两个重要因素。     

纳米体系粒度分布的X射线小角散射表征

本文简要介绍了国内外有关粒度分析标准的制定状况；重点描述了X射线小角散射法测定纳米粉末粒度分布的基本原理，数据处理方法和结果的实验验证；并对该分析方法的特点和若干相关问题进行了讨论。     

纳米二氧化硅粒径分析

本文对2个系列的纳米二氧化硅样品进行粒径分析。对单分散的纳米二氧化硅颗粒分别采用透射电镜和图像分析法、X射线小角散射法和动态光散射法测定其粒径,得到一致的结果。采用2种图像分析软件对另一纳米二氧化硅颗粒的透射电镜照片统计其粒径,得到一致的结果。     

Measurement of d-spacing of crystalline samples with SAXS

A method for measuring the d-spacing on scale of nanometers of a crystalline sample with a standard small angle X-ray scattering (SAXS) setup by moving either the sample or detector, instead of directly measuring sample-to-detector distance is presented. The formulae of the d-spacing and its errors are derived. The error variation is analyzed in detail by simulation. The effectiveness of the method is further verified by the experiments on a standard sample.     

角度加权对动态光散射信号噪声影响的抑制作用

在动态光散射技术中,光强自相关数据中信号噪声对测量结果的影响,主要取决于颗粒粒度反演算法。在多角度测量时,角度加权则成为左右噪声对测量结果影响的又一重要因素。本文在多角度动态光散射角度加权机理分析的基础上,研究了光强均值和迭代递归角度加权方法对测量信号噪声影响的抑制作用。结果表明,无信号噪声时,对于单峰小粒度分布,迭代递归方法加权对小颗粒粒度分布略有展宽;对于中、大颗粒,光强均值法进行角度加权所得的峰值误差略有增大;随着噪声的增加,迭代递归法加权所得反演结果的性能指标无显著变化,而光强均值法进行角度加权所得结果的峰值误差和分布误差均呈显著增大的趋势。306/974 nm标准双峰颗粒体系光强均值法和迭代递归法的反演峰值误差分别为0.170/0.121,0.092/0.097,迭代递归法峰值位置更准确,能够验证模拟数据的结论。迭代递归法通过各个散射角逐次反演和比较粒度分布重新计算角度权重,这种通过角度权重更新的“修正”作用,在很大程度上抵消了噪声导致的粒度分布误差,从而显现出抵御噪声影响的“去噪”性能。因此,在测量噪声较大的环境下,宜采用迭代递归方法进行多角度加权。     

一种新型激光粉尘浓度在线测量仪的研究

本文提出了一种基于光散射原理的粉尘浓度激光测量新方法，该方法无需预先获取粉尘颗粒的平均粒径，可直接测量浓度。基于新方法设计了一套粉尘浓度在线测量仪，测量仪以8031单片机为核心，具有浓度的实时LED显示和数模输出功能，并通过与上位机的串行通信实现浓度数据的后台存储。该仪器具有新颖的光学构造，可在单片机的控制下进行在线标定和在线光路对中，并已用于某钢厂粉尘排放的实时测量，测量结果表明仪器具有良好的灵敏度和可靠性，可满足实时在线测量粉尘浓度的要求。     

能量色散X射线荧光光谱仪快速测定土壤中Cu、Pb、Zn、Rb、Nb和Th6种元素

直接使用粉末样品,用便携式能量色散X射线荧光光谱仪测定土壤样品中的Cu、、Zn、Pb、Rb、Nb和Th等6种元素。使用土壤、水系沉积物标准样品建立校准曲线,用铑靶Kα线的康普顿散射线作为内标校正基体效应。方法简便、快速、准确。除Th精密度为13%外,各组分分析的精密度(RSD,n=12)均小于6%,完全能满足化探样品测定的要求。     

基于小偏转角和单表法的联轴器计算机辅助找正技术

针对传统找正方式的优缺点,寻求并推导出千分表在小偏转角的情况下计算联轴器径向偏差的几何原理.结合单表法找正技术,以小巧的上网本为编程平台,用VB实现可视化的联轴器计算机辅助找正过程,在满足大多数找正精度需要的情况下,用比激光对中仪低得多的成本实现了快速找正的目的.     

The effect of large solid angles of collection on quantitative X-ray microanalysis in the AEM

Increasing the solid angle of X-ray collection is a major factor in improving the analytical sensitivity of X-ray energy-dispersive spectrometry (XEDS) in the analytical electron microscope (AEM). A new scanning transmission electron microscope, the VG HB 603, is equipped with two XEDS detectors with the largest collection angles (0.30 and 0.17 sr) available in commercial AEMs. However, large collection angles result in a large range of take-off angles, from ~ 4° to 36°, and the low angles can cause strong X-ray absorption. In order to investigate possible detrimental effects of the low (and of the range of) take-off angles on quantitative microanalysis of specimens exhibiting significant absorption, a stoichiometric Ni₃Al thin-film, in which the Al Kα line is significantly absorbed, was analysed. Furthermore, the effect of different values of the collection angle on X-ray intensities was theoretically evaluated by numerical calculations and spectral simulation. These theoretical approaches permitted correlation of changes in the X-ray take-off angle (and hence X-ray absorption) with changes in the collection angle. It is demonstrated that ~ 0.30 sr detectors, with minimum take-off angles as small as 4°, only result in maximum errors of 4% in the quantification of Al in Ni₃Al and, therefore, further increases in collection angle can be pursued while maintaining current levels of accuracy of quantification.     

光散射在线分析系统

光散射在线分析系统是以斯坦教授的小角光散射法为理论基础，主要用于高分子材料内部结构的在线分析测试与研究。它是由硬件──光散射在线分析仪和软件──数据采集处理系统两大部分组成。该系统首创了高聚物内部结构的在线分析，并且成功地将数字图象处理技术应用于光散射图象的分析处理；由于计算机的优势和潜力，使得整个计算处理准确、快速，形象、直观，而且易于统一标准，从而提高了计算结果的可比性和可信度。     

表面接触角测量装置的设计

介绍了一种用于测量表面接触角的简易装置,目的是为材料表面的润湿性实验研究过程提供一种简易专用装置和方法,替代昂贵的专用测量仪器,用于快速评估被测样品表面的接触角。装置由样品台、光学系统、三维平移台、移液器和计算机组成,对被测样品表面具有一定体积的液滴通过光学系统成像,并将CCD相机与计算机相结合,对液滴形态图像进行存储和分析,从而得到被测样品的表面接触角。对装置的结构、功能和使用方法进行了介绍。     

Spatially resolved diffractometry with atomic-column resolution

We demonstrate spatially resolved diffractometry in which diffraction patterns are acquired at two-dimensional positions on a specimen using scanning transmission electron microscopy (STEM), resulting in four-dimensional data acquisition. A high spatial resolution of about 0.1 nm is achieved using a stabilized STEM instrument, a spherical aberration corrector and various post-acquisition data processings. We have found a few novel results in the radial and the azimuthal scattering angle dependences of atomic-column contrast in STEM images. Atomic columns are clearly observed in dark field images obtained using the excess Kikuchi band intensity even in small solid-angle detection. We also find that atomic-column contrasts in dark field images are shifted in the order of a few tens of picometers on changing the azimuthal scattering angle. This experimental result is approximately interpretable on the basis of the impact parameter in Rutherford scattering. Spatially resolved diffractometry provides fundamental knowledge related to various STEM techniques, such as annular dark field (ADF) and annular bright field (ABF) imaging, and it is expected to become an analytical platform for advanced STEM imaging.     

Dynamic light scattering in turbid nonergodic media

We here present a new device based on dynamic light scattering (DLS) for measuring kinetics in turbid and nonergodic systems. This flat cell light scattering instrument has been developed in our laboratory and is based on an original flat cell instrument employing cells of varying thickness in order to measure the static structure and dynamics of a system. The smallest cell thickness is 10 microm. To this original instrument, we have integrated the three-dimensional (3D)-DLS technology as well as the echo method, and in comparison with other 3D-DLS instruments, ours show the best performance; the maximum intercept was 0.6 as opposed to 0.15 for regular 3D-DLS devices (recently we reached beta=0.75). This was made possible by using crossed polarization filters for the two laser beams, thereby allowing the scattered light from both laser beams to be decoupled and the intercept to no longer be limited at the theoretical value of 0.25. The maximum weight fraction of the sample that is measurable with such a setup is more than ten times higher than with a standard 3D-DLS setup or with the flat cell instrument without the 3D technology. Consequently, with the 3D-DLS flat cell instrument presented here, it truly becomes possible to investigate turbid systems. Moreover, the echo method was integrated to enable measurements of nonergodic systems. Here, a new mechanical design of the echo-DLS component was necessary due to the different geometries of the flat cell in comparison with that of a standard cylindrical cell. The performance of our echo device was compared to that of our multispeckle instrument, and the results were in good agreement for correlation times up to 30,000 s and more. The main limitation of this instrument in its current version is the maximum scattering angle of about 50 degrees (or 30 degrees if echo is used).     

用于血栓弹力图仪的光电微小转角测量装置

血栓弹力图仪是测量全血凝结和纤溶过程动态变化的仪器,其关键技术之一是微小转角的测量。本文根据光杠杆原理,采用激光器结合光电位置传感器(PSD),研制了一套用于血栓弹力图仪的微小转角光学测量装置,其中PSD产生的微弱光电流信号经过I/V转换和差动电路放大,再采用sym3小波进行滤波去噪。之后选用不同粘度的液体进行实验,初步验证了该转角测量装置的可行性。     

一种小展角圆弧样板的检测方法

从分析传统的以半径误差作评定标准来评定圆弧样板的方法在应用于小展角大圆弧时出现的问题人手,认为此类方法对小展角圆弧的评定效果不理想。并提出一种精确可行的在小展角条件下标定圆弧样板的方法。     

表面散射浊度测量研究

本文在理论上计算了球形粒子对光的单次散射及多重散射解 ,证明了通过检测 90°方向散射光强度来获得样品浊度方案的优越性。随着样品浊度的增加 ,当考虑样品的多重光散射后 ,90°方向散射光强与浊度的线性度下降。设计了表面散射浊度在线测量系统 ,当 Formazin标准液在 0～ 1 0 0 0 NTU范围内时 ,获得了散射光强与浊度的线性度优于± 3% ,测量结果表明用表面散射法来测量浊度具有测量范围宽、线性好的优点。     

Characterization study on NIS X-ray beam qualities and its applications

Quality of low and medium energy X-ray beam at the National Institute for Standards (NIS) of Egypt is studied in details in accordance with the recommendations of the Bureau International des Poids et Measures (BIPM) consultative committee for ionizing radiation (CCRI). The Half Value Layer (HVL) at each applied voltage is precisely determined. The setting up for the X-ray tube according to the TRS No. 469 of IAEA is performed. The effective energy of X-ray is determined using Hyper Pure Germanium Detector (HPGD) connected to photon energy spectrometer. The X-ray air Kerma is measured using NIS secondary standard dosimetry system, which is traceable to the SI units through BIPM. A proposed method for non-invasive tube voltage determination by HPGD is performed. Consequently, all X-ray beam quality parameters are extracted and found to be complying with CCRI recommended values for NIS X-ray tube.