高分辨率透射电子显微镜
分辨率(逻辑)
光学
图像分辨率
材料科学
衍射
傅里叶变换
物理
交叉口(航空)
电子衍射
反射(计算机编程)
振幅
透射电子显微镜
计算机科学
工程类
航空航天工程
人工智能
程序设计语言
量子力学
标识
DOI:10.1017/s143192760001271x
摘要
The resolution of the high-resolution transmission electron microscope is limited by the specimen as well as by the HRTEM. For specimens that beam-damage, image resolution depends upon electron energy and electron dose. For small-cell crystalline specimens, Bragg’s law quantizes allowable reso-lutions, preventing image resolution from reaching instrumental resolutiqn. Specimen thickness be-comes increasingly important at higher resolutions. For a resolution of d(Å), we need the specimen to diffract at u=1/d. Consideration of the intersection of the Ewald sphere with the specimen shape trans-form (fig. 1) shows that thickness must be less than For a resolution pr 1.0A at 300keV, thickness must be less than 100A; to achieve 0.7A requires halving this value to 50A (fig.l). Resolution in an image depends on the spatial frequencies of the information (diffracted waves) trans-ferred from the amplitude spectrum (specimen exit-surface wavefunction) into the image intensity spec-trum (Fourier transform of the image intensity).
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