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643 results on '"Zhou, Guangwen"'

8. Composition-dependent ordering transformations in Pt–Fe nanoalloys

Author

Chen, Xiaobo, Zhang, Siming, Li, Can, Liu, Zhijuan, Sun, Xianhu, Cheng, Shaobo, Zakharov, Dmitri N, Hwang, Sooyeon, Zhu, Yimei, Fang, Jiye, Wang, Guofeng, and Zhou, Guangwen

Subjects
Macromolecular and Materials Chemistry, Chemical Sciences, Physical Sciences, Pt–Fe nanoparticles, alloy composition, chemical ordering, in situ electron microscopy
Abstract

SignificanceDynamically understanding the microscopic processes governing ordering transformations has rarely been attained. The situation becomes even more challenging for nanoscale alloys, where the significantly increased surface-area-to-volume ratio not only opens up a variety of additional freedoms to initiate an ordering transformation but also allows for kinetic interplay between the surface and bulk due to their close proximity. We provide direct evidence of the microscopic processes controlling the ordering transformation through the surface-bulk interplay in Pt-Fe nanoalloys and new features rendered by variations in alloy composition and chemical stimuli. These results provide a mechanistic detail of ordering transformation phenomena which are widely relevant to nanoalloys as chemical ordering occurs in most multicomponent materials under suitable environmental bias.

Published
2022

15. Atomic-scale phase separation induced clustering of solute atoms.

Author

Zou, Lianfeng, Cao, Penghui, Lei, Yinkai, Zakharov, Dmitri, Sun, Xianhu, House, Stephen D, Luo, Langli, Li, Jonathan, Yang, Yang, Yin, Qiyue, Chen, Xiaobo, Li, Chaoran, Qin, Hailang, Stach, Eric A, Yang, Judith C, Wang, Guofeng, and Zhou, Guangwen

Abstract

Dealloying typically occurs via the chemical dissolution of an alloy component through a corrosion process. In contrast, here we report an atomic-scale nonchemical dealloying process that results in the clustering of solute atoms. We show that the disparity in the adatom-substrate exchange barriers separate Cu adatoms from a Cu-Au mixture, leaving behind a fluid phase enriched with Au adatoms that subsequently aggregate into supported clusters. Using dynamic, atomic-scale electron microscopy observations and theoretical modeling, we delineate the atomic-scale mechanisms associated with the nucleation, rotation and amorphization-crystallization oscillations of the Au clusters. We expect broader applicability of the results because the phase separation process is dictated by the inherent asymmetric adatom-substrate exchange barriers for separating dissimilar atoms in multicomponent materials.

Published
2020

16. Surface-reaction induced structural oscillations in the subsurface

Author

Sun, Xianhu, Zhu, Wenhui, Wu, Dongxiang, Li, Chaoran, Wang, Jianyu, Zhu, Yaguang, Chen, Xiaobo, Boscoboinik, Jorge Anibal, Sharma, Renu, and Zhou, Guangwen

Subjects
Physical Sciences, Engineering, Chemical Sciences, Physical Chemistry
Abstract

Surface and subsurface are commonly considered as separate entities because of the difference in the bonding environment and are often investigated separately due to the experimental challenges in differentiating the surface and subsurface effects. Using in-situ atomic-scale transmission electron microscopy to resolve the surface and subsurface at the same time, we show that the hydrogen-CuO surface reaction results in structural oscillations in deeper atomic layers via the cycles of ordering and disordering of oxygen vacancies in the subsurface. Together with atomistic calculations, we show that the structural oscillations in the subsurface are induced by the hydrogen oxidation-induced cyclic loss of oxygen from the oxide surface. These results demonstrate the propagation of the surface reaction dynamics into the deeper layers in inducing nonstoichiometry in the subsurface and have significant implications in modulating various chemical processes involving surface-subsurface mass transport such as heterogeneous catalysis, oxidation, corrosion and carburization.

Published
2020

20. Screening of Fungi for the Application of Self-Healing Concrete

Author

Menon, Rakenth R., Luo, Jing, Chen, Xiaobo, Zhou, Hui, Liu, Zhiyong, Zhou, Guangwen, Zhang, Ning, and Jin, Congrui

Subjects
Quantitative Biology - Other Quantitative Biology, Physics - Applied Physics
Abstract

Concrete is susceptible to cracking owing to drying shrinkage, freeze-thaw cycles, delayed ettringite formation, reinforcement corrosion, creep and fatigue, etc. Since maintenance and inspection of concrete infrastructure require onerous labor and high costs, self-healing of harmful cracks without human interference or intervention could be of great attraction. The goal of this study is to explore a new self-healing approach in which fungi are used as a self-healing agent to promote calcium carbonate precipitation to fill the cracks in concrete structures. Recent research results in the field of geomycology have shown that many species of fungi could play an important role in promoting calcium carbonate mineralization, but their application in self-healing concrete has not been reported. Therefore, a screening of different species of fungi has been conducted in this study. Our results showed that, despite the drastic pH increase owing to the leaching of calcium hydroxide from concrete, Aspergillus nidulans (MAD1445), a pH regulatory mutant, could grow on concrete plates and promote calcium carbonate precipitation., Comment: 21 pages. arXiv admin note: text overlap with arXiv:1708.01337

Published
2017

22. Interactions of Fungi with Concrete: Significant Importance for Bio-Based Self-Healing Concrete

Author

Luo, Jing, Chen, Xiaobo, Crump, Jada, Zhou, Hui, Davies, David G., Zhou, Guangwen, Zhang, Ning, and Jin, Congrui

Subjects
Quantitative Biology - Other Quantitative Biology, Physics - Applied Physics
Abstract

The goal of this study is to explore a new self-healing concept in which fungi are used as a self-healing agent to promote calcium mineral precipitation to fill the cracks in concrete. An initial screening of different species of fungi has been conducted. Fungal growth medium was overlaid onto cured concrete plate. Mycelial discs were aseptically deposited at the plate center. The results showed that, due to the dissolving of Ca(OH)2 from concrete, the pH of the growth medium increased from its original value of 6.5 to 13.0. Despite the drastic pH increase, Trichoderma reesei (ATCC13631) spores germinated into hyphal mycelium and grew equally well with or without concrete. X-ray diffraction (XRD) and scanning electron microscope (SEM) confirmed that the crystals precipitated on the fungal hyphae were composed of calcite. These results indicate that T. reesei has great potential to be used in bio-based self-healing concrete for sustainable infrastructure.

Published
2017

25. Tuning Strong Metal–Support Interactions via Synergistic Alloying

Author

Wang, Jianyu, primary, Chen, Xiaobo, additional, Li, Chaoran, additional, Zhu, Yaguang, additional, Li, Jing, additional, Shan, Shiyao, additional, Hunt, Adrian, additional, Waluyo, Iradwikanari, additional, Boscoboinik, J. Anibal, additional, Zhong, Chuan-Jian, additional, and Zhou, Guangwen, additional

Published
2024
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31. Spindle Fault Prediction Based on Improved Fuzzy Neural Network Algorithm

Author

Zhou, Guangwen, Mao, Chunyu, Tian, Mei, Kacprzyk, Janusz, Series Editor, Pal, Nikhil R., Advisory Editor, Bello Perez, Rafael, Advisory Editor, Corchado, Emilio S., Advisory Editor, Hagras, Hani, Advisory Editor, Kóczy, László T., Advisory Editor, Kreinovich, Vladik, Advisory Editor, Lin, Chin-Teng, Advisory Editor, Lu, Jie, Advisory Editor, Melin, Patricia, Advisory Editor, Nedjah, Nadia, Advisory Editor, Nguyen, Ngoc Thanh, Advisory Editor, Wang, Jun, Advisory Editor, Abawajy, Jemal, editor, Choo, Kim-Kwang Raymond, editor, Islam, Rafiqul, editor, Xu, Zheng, editor, and Atiquzzaman, Mohammed, editor

Published
2019
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37. Atomistic mechanisms of water vapor–induced surface passivation

Author

Chen, Xiaobo, primary, Shan, Weitao, additional, Wu, Dongxiang, additional, Patel, Shyam Bharatkumar, additional, Cai, Na, additional, Li, Chaoran, additional, Ye, Shuonan, additional, Liu, Zhao, additional, Hwang, Sooyeon, additional, Zakharov, Dmitri N., additional, Boscoboinik, Jorge Anibal, additional, Wang, Guofeng, additional, and Zhou, Guangwen, additional

Published
2023
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