Exploration | 微观世界的奇妙探索之旅（三）
继扫描电子显微镜、聚焦离子/电子双束显微镜之后，又一台新设备——透射电子显微镜“入驻”广东以色列理工学院电镜中心。
透射电子显微镜与其他两台电镜有何不同？它将在哪些领域大显神通？广以君这就带你一睹为快！
认识自然、探索未知是人类不懈的追求。利用丰富多样的仪器设备进行观察、分析、研究，便是人们探索奥秘的重要手段之一。广以电镜中心的透射电子显微镜（Transmission Electron Microscope - TEM）便是这样一台帮助科研人员进行跨学科、多维度研究工作的科研“神器”。
这台透射电子显微镜的型号为Thermo Scientific Talos F200X，它结合了高分辨率的透射和扫描透射（Scanning Transmission Electron Microscope - STEM）成像技术与行业领先的能量色散X射线光谱（Energy Dispersive X-ray Spectroscopy - EDS）信号检测技术，是一台分析型电镜。
Talos的突出优势在于配备了集成四个硅漂移探测器 （Silicon Drift Detectors - SDD）的EDS系统，能够最大限度地提高X-ray的收集效率，可以快速准确地对样品进行成分分析。
加速电压：200 kV、120 kV、80 kV
TEM信息分辨率：0.12 nm
STEM高角度环形暗场像分辨率：0.16 nm
EDS能量分辨率：≤136 eV
高分辨率TEM成像（明场像、暗场像、原子像）
高质量电子衍射分析（选区电子衍射、纳米束电子衍射、会聚束电子衍射）
高分辨率STEM成像（明场像、暗场像、高角度环形暗场像、差分相位衬度成像）
快速精确EDS分析（点扫描、线扫描、面扫描）
TEM、STEM、EDS三维重构
洛伦兹模式成像
Talos可应用于材料科学、能源科学与生命科学领域多种材料多维度的表征与测试。以下是部分应用举例：
1AlSi10Mg合金图(a)为AlSi10Mg合金高角度环形暗场像，图(b)、(c)、(d)、(e)分别为样品中Al、Ti、Mg、Fe元素的面分布图，图(f)为样品中Al、Ti、Fe元素分布的位置叠加图。
AlSi10Mg合金EDS元素面分布图
AlSi10Mg合金TEM高分辨原子像
TiAl合金中存在α₂相与γ相板条结构，且α₂相与γ相满足(0001)α₂ // (111)γ、[2-1-10]α₂ // [110]γ的位向关系，同时该区域中存在γ相的孪晶结构。
TiAl合金形貌像（左）与选区电子衍射花样（右）
TEM模式下，钙钛矿量子点内部的原子排列。
高角度环形暗场模式下，薄膜与衬底的界面清晰可见，薄膜层中哑铃状双原子结构的原子间距仅为0.16 nm。
薄膜材料STEM高分辨原子像
左图是正常小鼠食管上皮组织，胞质中可见线粒体，上皮细胞间可见桥粒结构。右图是病变小鼠食管上皮组织，胞质内中线粒体消失，上皮细胞间桥粒减少。
正常（左）/病变（右）小鼠食管上皮组织形貌像
广东以色列理工学院拥有世界一流的学术环境和科研团队。广以材料学院电镜中心(Electron Microscopy Center-EMC)是一个跨领域、跨学科，集分析测试服务、基础研究和应用研究为一体的综合性开放平台。电镜中心以材料的微观表征为切入点，用多种电子显微方法研究不同材料的微观结构和化学成分(可至原子水平)，并建立微观结构、化学成分和材料性能之间的内秉关系，为材料性能优化和进一步应用提供基本的科学支撑。
延伸阅读：
After the Scanning Electron Microscope and Focused Ion/Electron DualBeam Microscope, Transmission Electron Microscope (TEM), another new equipment entered the Electron Microscope Center of GTIIT.
How is the transmission electron microscope different from the other two electron microscopes? In what areas will it work? Let's take a look!
Exploring the unknown is the unremitting pursuit of mankind. The use of a variety of instruments and equipment for observation, analysis and research is one of the important means of people to explore the mystery. The transmission electron microscope (TEM) in the Electron Microscope Center of GTIIT is such an efficient equipment to support researchers to carry out interdisciplinary and multi-dimensional research work.
It is Thermo Scientific Talos F200X, which combines high resolution transmission and scanning transmission electron microscope (STEM) imaging with industry-leading energy dispersive X-ray spectroscopy (EDS) signal detection. As an analytical electron microscope, the outstanding advantage of it is that Talos is equipped with the EDS system integrating four silicon drift detectors (SDD), which can maximize the collection efficiency of X-ray and analyze the composition of samples quickly and accurately.
Main specifications
Accelerating voltage: 200 kV, 120 kV, 80 kV
TEM information limit: 0.12 nm
STEM High Angle Annular Dark Field (HAADF) resolution: 0.16 nm
EDS energy resolution: ≤136 eV
Main Functions
High resolution TEM imaging
Bright field (BF) image, dark field (DF) image,
atomic image
High quality electron diffraction analysis
Selected area electron diffraction (SAED),
nano beam electron diffraction (NBED),
convergent beam electron diffraction (CBED)
High resolution STEM imaging
BF image, DF image, HAADF image, differential
phase contrast (DPC) imaging
Fast and accurate EDS analysis
Point scanning, line scanning, area scanning
TEM, STEM, EDS 3D reconstruction
Lorentz imaging
Application area
Talos can be applied to multi-dimensional characterization and testing of various materials in the fields of materials science, energy science and life science. The following are some application examples:
AlSi10Mg alloy
Figure (a) is the STEM-HAADF image of AlSi10Mg alloy, figures (b), (c), (d) and (e) show the distribution of Al, Ti, Mg and Fe elements in the sample respectively, and figure (f) shows the overlap of the Al, Ti and Fe elements distribution in the sample.
EDS elements mapping of AlSi10Mg alloy
The (111) plane (d=2.34Å), the (1-1-1) plane (d=2.34Å) and the (200) plane (d=2.02Å) under the [01-1] zone axis.
The TEM image and the diffraction pattern show the α₂ phase and γ phase with lamellar structure in the TiAl alloy, which satisfied the (0001)α₂ // (111)γ, [2-1-10]α₂ // [110]γ orientation relationship, and there are γ twins in this area.
TEM bright field image (left) and selected area electron diffraction pattern (right) of TiAl alloy
The atom arrangement in perovskite quantum dots.
The STEM-HAADF image shows the sharp interface between the film and the substrate, and the distance between atoms of the dumbbell diatomic structure in the upper film is 0.16 nm only.
The image left shows the normal mouse esophageal epithelium. Mitochondria can be seen in the cytoplasm, and the desmosomes can be seen between epithelial cells. The image right shows the diseased mouse esophageal epithelium. Mitochondria in the cytoplasm disappeared, and the desmosomes between epithelial cells decreased.
TEM bright field image of normal (left)/ diseased (right) mouse esophageal epithelium
GTIIT Electron Microscopy Center (EMC)
GTIIT has world-class academic environment and research teams. The Electron Microscopy Center (EMC) of GTIIT is an open platform that integrates analytical testing services, fundamental research and applied research. EMC takes the micro characterization of materials as the entry point, studies the microstructure and chemical composition of different materials (up to the atomic level) by a variety of electron microscopy methods, and establishes the internal relationship among the microstructure, chemical composition and material performance, providing basic scientific support for material performance optimization and further application.
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文/图：GTIIT传媒与公共事务部、GTIIT电镜中心
Text/Photos: GTIIT News & Public Affairs, GTIIT Electron Microscopy Center