共查询到19条相似文献,搜索用时 203 毫秒
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基于微分干涉相衬的相位分析法研究 总被引:2,自引:0,他引:2
通过对微分干涉相衬显微定量测量方法进行研究,提出了一种更有效的相位分析法。即在不对双光束干涉光路进行改造或处理的前提下,通过对光学成像进行处理而得到理想的结果。即把图像中的光强信号转变成相位信号,并通过维纳滤波对噪声进行了消除,最后获得表面微观形貌定量参数。 相似文献
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郝建民 《现代仪器使用与维修》1999,(2):5-8
本文介绍X射线多重衍射效应的起因,多重衍射图谱的指标化,给出了用普通X射线粉末衍射仪观测多重衍射效应的方法,并简要说明了多重衍射效应的应用。 相似文献
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The ratio of inelastic-to-elastic total cross-sections has been measured in an energy-filtering electron microscope for different elements. Formulae for the transmission of elastically and inelastically scattered electrons in part I were used to calculate the optimum conditions for a Z-ratio contrast in the electron spectroscopic imaging mode. Structure-sensitive contrast can be observed for all non-carbon atoms in biological sections when filtering with an energy loss at ΔE ~ 250 eV below the carbon K edge. Model experiments with evaporated layers of different elements on a carbon film allow measurement of the contrast increase. Filtering with the carbon plasmon loss shows a lower phase contrast than with zero-loss filtering. This can be explained by calculating contrast transfer functions for inelastically scattered electrons. 相似文献
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Yuan Ji Li Wang Xueling Quan Jingyong Fu Yinqi Zhang Xuedong Xu Taoxing Zhong Bin Wei Cuixiu Liu 《Scanning》2007,29(5):230-237
The charge contrast images (CCI) on insulating or poorly conducting samples were observed under steady‐state charging conditions with a thermal field emission scanning electron microscope under high vacuum by using an Everhart‐Thornley detector. The charge contrast on plumbous titanate‐nickel composite particles and patterned sapphires could be the indicators of near‐surface features, compositional variations and conductivity distributions. Optimum imaging conditions for observing the CCI include the electron energy, the electron flux density and the electron dose. Contrast characteristics associated with surface and near‐surface secondary electron emission yield enhanced above the trapped charge‐up regions, as charge trapping selectively enhanced the poorly conductive phase and lattice distorted area. SCANNING 29: 230‐237, 2007. © 2007 Wiley Periodicals, Inc. 相似文献
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A conventional global contrast enhancement is difficult to apply in various images because image quality and contrast enhancement are depndent on image characteristics largely.And a local contrast enhancement not only causes a washed-out effect,but also blocks.To solve these drawbacks,this paper derives an optimal global equalization function with variable size block based local contrast enhancement.The optimal equalization function makes it possible to get a good quality image through the global contrast enhancement.The variable size block segmentation is firstly executed using intensity differences as a measure of similarity.In the second step,the optimal global equalization function is obtained from the enhanced contrast image having variable size blocks.Conformed experiments have showed that the proposed algorithm produces a visually comfortable result image. 相似文献
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Measured values of the transmission of amorphous films as a function of the objective aperture and film thickness can be described by a single-scattering theory for unfiltered and zero-loss filtered images in the electron spectroscopic imaging mode of a transmission electron microscope. The theory can be applied to estimate the gain of contrast by zero-loss filtering for specimen structures larger and smaller than the chromatic aberration disc. 相似文献
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X射线数字成像检测与诊断技术是X射线检测的发展趋势,微型X射线数字成像系统采用X射线敏感CCD面阵探测器作为射线探测元件,具有体积小、分辨率高、实时性好的特点。本文研制了基于X射线敏感CCD的微型X射线数字成像系统,介绍了整个系统的组成,阐述了X射线敏感CCD的工作原理,选定了系统采用的X射线敏感CCD,设计了CCD探测器的驱动电路、模数转化电路、数据采集与通讯电路、图像获取及处理软件等。该系统采用USB2.0接口与计算机进行通讯,直接采用USB接口电源供电,无需外部电源,结构简单。分辨率测试表明,该系统的分辨率>10lp/mm。 相似文献
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Phase differentiation via combined EBSD and XEDS 总被引:2,自引:0,他引:2
Electron backscatter diffraction (EBSD) and orientation imaging microscopy have become established techniques for analysing the crystallographic microstructure of single and multiphase materials. In certain instances, however, it can be difficult and/or time intensive to differentiate phases within a material by crystallography alone. Traditionally a list of candidate phases is specified prior to data collection. The crystallographic information extracted from the diffraction patterns is then compared with the crystallographic information from these candidate phases, and a best‐fit match is determined. Problems may arise when two phases have similar crystal structures. The phase differentiation process can be improved by collecting chemical information through X‐ray energy‐dispersive spectroscopy (XEDS) simultaneously with the crystallographic information through EBSD and then using the chemical information to pre‐filter the crystallographic phase candidates. This technique improves both the overall speed of the data collection and the accuracy of the final characterization. Examples of this process and the limitations involved will be presented and discussed. 相似文献