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Abstract X-ray analysis is one of the most robust approaches to extract quantitative information from various materials and is widely used in various fields ever since Raimond Castaing established procedures to analyze electron-induced X-ray signals for materials characterization ‘70 years ago’. The recent development of aberration-correction technology in a (scanning) transmission electron microscopes (S/TEMs) offers refined electron probes below the Å level, making atomic-resolution X-ray analysis possible. In addition, the latest silicon drift detectors allow complex detector arrangements and new configurational designs to maximize the collection efficiency of X-ray signals, which make it feasible to acquire X-ray signals from single atoms. In this review paper, recent progress and advantages related to S/TEM-based X-ray analysis will be discussed: (i) progress in quantification for materials characterization including the recent applications to light element analysis, (ii) progress in analytical spatial resolution for atomic-resolution analysis and (iii) progress in analytical sensitivity toward single-atom detection and analysis in materials. Both atomic-resolution analysis and single-atom analysis are evaluated theoretically through multislice-based calculation for electron propagation in oriented crystalline specimen in combination with X-ray spectrum simulation.
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Advances in characterizing and understanding the microstructure of cementitious materials
Progress in microstructural characterization methods is summarized. Special attention is given to advanced probes, such as X-ray imaging and spectroscopy, 1H NMR relaxometry, in-situ and high-pressure X-ray diffraction, and digital holographic microscopy. Microtomography has become a mature technique and nanotography has improved its spatial resolution significantly, particularly with the use of ptychography. The review also discusses the effect of plasticizers on the microstructure of concrete and presents a critical analysis of how organic admixtures affects the hydrates obtained from pure synthesis in saturated solutions and from more realistic hydrating systems. The addition of nanomaterials into cementitious systems modifies the microstructure of the matrix so a summary of recent research is presented. It is important to integrate the impressive progress in the characterization of the micro(nano)structure with efforts developing realistic models. Therefore, the present work gives a short but critical presentation of physical chemistry approaches that aim to link the chemical composition, texture, and microstructure of the cement hydrates.
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- Award ID(s):
- 1826122
- PAR ID:
- 10157900
- Date Published:
- Journal Name:
- Cement and concrete research
- Volume:
- 124
- ISSN:
- 0008-8846
- Page Range / eLocation ID:
- 105806
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/https://doi.org/10.1016/j.cemconres.2019.105806
