相关实验视频

Updated: Jul 11, 2025

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization

Published on: July 17, 2015

在厚样本的直接电子图谱中,用于对比度优化的中央聚焦

C Gao¹, C Hofer¹, T J Pennycook¹

¹EMAT, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium; NANOlab Center of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium.

Ultramicroscopy

|November 9, 2023

概括

可通过将探针聚焦到样品的中间,防止对比度逆转来改善图像摄影. 调整收角也有助于在薄样本的对比逆转移除.

科学领域:

材料科学材料科学材料科学
影像成像技术影像成像技术
物理物理学物理

背景情况:

图解学提供了高剂量效率的成像轻元素与重原子一起.
对比逆转可以发生在图解学中,即使使用单签的对比转移函数,特别是具有强大的投射潜力.
调整探头焦点已被证明可以抵消这些逆转在直接图解法方法.

研究的目的:

解释为什么将探头聚焦到样本的中间可以优化图解学中的对比度.
调查失焦和动态散射在对比逆转中的作用.
为了探索收角对对比度逆转移除的影响.

主要方法:

从样本切片中对相位贡献的理论分析.
调查直接和代的反转图形法方法.
在不同的焦点和收角度下检查对比度反转.

主要成果:

将探头聚焦到样品的中间,导致取消失焦的相位贡献,防止当动态散射不占主导地位时对比度反转.
收角度被认为是减轻较薄样本对比率逆转的关键因素.

结论:

将探头的焦点优化到样本的中心是实现高对比度图形图像和避免反转的关键策略.
了解焦点,样本深度和动态散射之间的相互作用对于强大的图解学至关重要.
收角度调整提供了一种额外的方法来减轻对比率逆转,特别是在薄的标本中.

关键词:

在4D STEM中,电子影像学电子影像学电子影像学低剂量的低剂量扫描传输电子显微镜扫描传输电子显微镜

更多相关视频

Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography

Preparation and Observation of Thick Biological Samples by Scanning Transmission Electron Tomography

Published on: March 12, 2017

Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy

Optimized Negative Staining: a High-throughput Protocol for Examining Small and Asymmetric Protein Structure by Electron Microscopy

Published on: August 15, 2014

相关概念视频

Phase Contrast and Differential Interference Contrast Microscopy

Phase Contrast and Differential Interference Contrast Microscopy

Phase-Contrast Microscopes
In-phase-contrast microscopes, interference between light directly passing through a cell and light refracted by cellular components is used to create high-contrast, high-resolution images without staining. It is the oldest and simplest type of microscope that creates an image by altering the wavelengths of light rays passing through the specimen. Altered wavelength paths are created using an annular stop in the condenser. The annular stop produces a hollow cone of...

Electron Microscope Tomography and Single-particle Reconstruction

Electron Microscope Tomography and Single-particle Reconstruction

Transmission electron microscopy (TEM) can be used to determine the 3D structure of biological samples with the help of techniques such as electron microscope tomography and single-particle reconstruction. While single-particle reconstruction can examine macromolecules and macromolecular complexes in vitro conditions only, tomography permits the study of cell components or small cells in vivo.
Electron Tomography
Electron tomography can be performed either in TEM or STEM (scanning transmission...

Preparation of Samples for Electron Microscopy

Preparation of Samples for Electron Microscopy

To be visualized by an electron microscope, either transmission or scanning, biological samples need to be fixed (stabilized) so the electron beam does not destroy them and dried thoroughly (desiccated/dehydrated) so the vacuum does not affect them. Fixation needs to be done as quickly as possible because the sample properties will start changing as soon as it is removed from its natural environment. For example, in a tissue sample, the oxygen levels begin decreasing, causing an altered...