基于离散Fourier变换的内源全息图重构计算方法

对基于离散Fourier变换的内源全息图重构计算方法作了深入系统的分析，讨论了如何计算整个球面全息图对原子重构像的贡献，克服了以往该方法只能计算半个球面全息图的不足，并运用采样定理知识，分析了全息图的采样率、重构像的空间范围和分辨率等问题. 关键词： 内源全息术 离散Fourier变换 采样定理 同步辐射     

高能X射线组合透镜聚焦性能的实验结果

高能X射线组合透镜是一种基于折射效应的新型X射线光学元件。报道了这种新型X射线光学元件聚焦性能的最新实验结果。设计的高能X射线组合透镜为聚甲基丙烯酸甲酯(PMMA)材料,包括40个相同的、顺序排布的平凹折射单元,折射单元的球面半径为200μm,组合透镜的几何口径约为500μm,长度约为8 mm,焦距约为1.3 m。简要描述了PMMA材料X射线组合透镜的制作技术和制作过程。并给出了X射线组合透镜聚焦性能测试实验系统和实验条件。最后给出8 keV单色X射线辐射下,PMMA材料X射线组合透镜的聚焦性能的测试结果,对实际测试结果进行了分析和讨论,得出结论,焦距等参量与理论计算结果基本吻合。     

X射线衍射增强成像中的信息分离和信息处理

人们已经利用X射线的高穿透性,发展了较为成熟的X射线成像理论和技术. X射线成像已经广泛应用于众多领域.传统X射线成像受生物样品中组织间吸收系数差别较小和散射噪声较大两个因素的限制,不易利用这种方法获得生物组织的信息. 衍射增强成像方法不但能将有害的散射噪声滤除,而且能利用样品的折射信息, 是一种具有发展潜力的新成像方法. 本文利用衍射增强成像, 通过在摇摆曲线不同部位成像, 然后对信息处理, 得到了清晰的吸收像、消光(小角散射滤除)像、小角散射(角)宽度像和折射像,最后通过一定的算法将各种成分的像合成, 形成细节部位清晰的合成伪彩色像.     

钼酸钆晶体的高温喇曼光谱

对提拉法生长的钼酸钆晶体进行了从常温(25℃)到高温(1127℃)的喇曼光谱测试和分析,由实验得出:随着温度的不断升高,晶体的喇曼谱峰向低频移动(159℃相变点除外),且总的趋势是向一起靠拢,位置相近的谱峰合并或趋于合并,这说明随着温度的升高晶体结构不断变化-晶体中三种MoO4四面体的结构逐渐趋于一致.用经验关系式υ(cm-1)=32895exp(-2.073r),由实验测得的晶体在不同温度下的喇曼伸缩振动频率值估算了相应温度下晶体中MoO4四面体的Mo-O键的键长值,明显看出,随着温度的升高,各不同的四面体的键长值趋于一致,从而定量估算出晶体结构随温度的变化情况.     

β′-Gd2(MoO4)3晶体生长中的过冷现象研究

对电阻加热引上法和感应加热引上法生长β′-Gd2(MoO4)3晶体的实验结果进行了比较,分析了两种方法生长晶体过程中熔体过冷和组分过冷的情况.研究认为组分过冷主要与生长过程中MoO3的挥发、Gd2(MoO4)3熔体的粘度及固液界面的温度梯度有关,并认为感应加热引上法较之电阻加热引上法容易得到优质晶体.     

Focusing high-energy x-rays by a PMMA compound x-ray lens on Beijing synchrotron radiation facility

The x-ray compound lens is a novel refractive x-ray optical device. This paper reports the authors' recent research on a polymethyl methacrylate (PMMA) compound x-ray lens. Firstly the designing and LIGA fabrication process for the PMMA compound x-ray lens are briefly described. Then, a method for theoretical analysis, as well as the experimental system for measurement is also introduced. Finally, the focusing spots for 8keV monochromatic x-rays by the PMMA compound x-ray lens are measured and analysed. According to the experimental results, it is concluded that the PMMA compound x-ray lens promises a good focusing performance under the high-energy x-rays.     

DEIReconstructor:a software for diffraction enhanced imaging processing and tomography reconstruction

Diffraction enhanced imaging (DEI) has been widely applied in many fields, especially when imaging low-Z samples or when the difference in the attenuation coefficient between different regions in the sample is too small to be detected. Recent developments of this technique have presented a need for a new software package for data analysis. Here, the Diffraction Enhanced Image Reconstructor (DEIReconstructor), developed in Matlab, is presented. DEIReconstructor has a user-friendly graphical user interface and runs under any of the 32-bit or 64-bit Microsoft Windows operating systems including XP and Win7. Many of its features are integrated to support imaging preprocessing, extract absorption, refractive and scattering information of diffraction enhanced imaging and allow for parallel-beam tomography reconstruction for DEI-CT. Furthermore, many other useful functions are also implemented in order to simplify the data analysis and the presentation of results. The compiled software package is freely available.     

DEIReconstructor： a software for diffraction enhanced imaging processing and tomography reconstruction

Diffraction enhanced imaging （DEI） has been widely applied in many fields, especially when imaging low-Z samples or when the difference in the attenuation coefficient between different regions in the sample is too small to be detected. Recent developments of this technique have presented a need for a new software package for data analysis. Here, the Diffraction Enhanced Image Reconstructor （DEIReconstructor）, developed in Matlab, is presented. DEIReconstructor has a user-friendly graphical user interface and runs under any of the 32~bit or 64- bit Microsoft Windows operating systems including XP and WinT. Many of its features are integrated to support imaging preprocessing, extract absorption, refractive and scattering information of diffraction enhanced imaging and allow for parallel-beam tomography reconstruction for DEI-CT. Furthermore, many other useful functions are also implemented in order to simplify the data analysis and the presentation of results. The compiled software package is freely available.     

X射线衍射增强相衬成像的实验结果

报道了X射线衍射增强相衬成像的最新实验结果,简要论述了其原理,证明了衍射增强X射线相衬成像是一种高信噪比的成像方法,它比普通的X射线成像和层析(CT)具有高得多的分辨力,约为10μm,这在临床医学、材料科学及其它一些生物研究领域具有巨大的应用潜力。