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386 results on '"Xu Mingfeng"'

61. Hydration mechanism of anhydrite and calcium sulfoaluminate co-activated slag cement: insights into the role of composition.

Author

Yang, Ken, Sun, Zixuan, Zhou, Jian, Xu, Mingfeng, Wu, Kai, Yang, Xiaojie, Xu, Linglin, and Guo, Lijie

Subjects
SLAG cement, SULFOALUMINATE cement, PORTLAND cement, CEMENT clinkers, ANHYDRITE, HEAT of hydration, GYPSUM
Abstract

Utilization of Portland cement to initiate the dissolution of blast furnace slag (BFS) in super-sulfated cement is limited by low slag substitution level and poor early strength. In this study, a new activator composed of anhydrite and calcium sulfoaluminate cement clinker was proposed to enhance the utilization of BFS in super-sulfated cement. Tests were conducted on the compressive strength, autogenous shrinkage, hydration heat, pH and conductivity of the composites. XRD, 29Si NMR, BSE and MIP were employed. Results reveal that ettringite, gypsum and C-S-H are the primary hydration products. The composites with 20% activator display the highest compressive strength and shrinkage accompanied by the highest hydration heat and degree, as well as the highest quantity of monomer silica tetrahedrons and the largest volume of fine pores. Thermodynamic modeling confirms the critical value for the activator-substitution level. Additionally, the activator-BFS composite exhibited significantly lower carbon emissions compared to Portland cement. [ABSTRACT FROM AUTHOR]

Published
2024
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71. Vector optical field manipulation via structural functional materials: Tutorial.

Author

Luo, Xiangang, Pu, Mingbo, Zhang, Fei, Xu, Mingfeng, Guo, Yinghui, Li, Xiong, and Ma, Xiaoliang

Abstract

Vector optical field (VOF) manipulation greatly extended the boundaries of traditional scalar optics over the past decades. Meanwhile, the newly emerging techniques enabled by structural functional optical materials have driven the research domain into the subwavelength regime, where abundant new physical phenomena and technologies have been discovered and exploited for practical applications. In this Tutorial, we outline the basic principles, methodologies, and applications of VOF via structural functional materials. Among various technical routes, we focus on the metasurface-based approaches, which show obvious advantages regarding the design flexibility, the compactness of systems, and the overall performances. Both forward and inverse design methods based on the rigorous solution of Maxwell's equations are presented, which provide a valuable basis for future researchers. Finally, we discuss the generalized optical laws and conventions based on VOF manipulation. The applications in optical imaging, communications, precision measurement, laser fabrication, etc. are highlighted. [ABSTRACT FROM AUTHOR]

Published
2022
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76. Alignment‐Free Angular Momentum Detection via Spin‐Independent Astigmatic Transformation.

Author

Jiang, Mengna, Chen, Yan, Zhang, Fei, Pu, Mingbo, Guo, Yinghui, Xu, Mingfeng, Yue, Weisheng, He, Qiong, Gao, Ping, and Luo, Xiangang

Subjects
ANGULAR momentum (Mechanics), ASTIGMATISM, VECTOR beams, OPTICAL tweezers, DIFFRACTION patterns, OPTICAL communications, ASTIGMATISM (Optics)
Abstract

Light beam carrying spin angular momentum (SAM) and orbital angular momentum (OAM) have attracted great interest due to their great potential for high‐capacity optical communication, optical tweezers, and quantum information. However, the current detection methods suffer from the lack of robustness to misalignments in the optical system, which limits the detection accuracy and the application for off‐axis vortex array detection. Here, a high‐efficiency, broadband, and single‐layer metasurface design is proposed for alignment‐free angular momentum detection via spin‐independent astigmatic transformation (SIAT). The SAM and OAM states can be recognized from the diffraction direction and patterns, respectively. Proof‐of‐concept demonstrations are experimentally carried out on different incident beams including circular‐polarization, linear‐polarization, and vector vortex beams, as well as vortex beam arrays, showing a high diffraction efficiency of ≈81% at 1064 nm while operating within the broadband region of 900–1300 nm. The alignment‐free merit for the incident position, incident angle, and detector distance grants the device great potential for integrated quantum systems and multiparticle micromanipulation with optical tweezers. [ABSTRACT FROM AUTHOR]

Published
2024
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83. Experimental Demonstration of All-Optical 8-Gbit/s Secure Free-Space Chaotic Communications over 8.2-meter Link Based on Unidirectional Injection-Locking Chaos Synchronization

Author

Zhang, Yiqun, primary, Xu, Mingfeng, additional, Chen, Qiang, additional, Zhou, Mengjie, additional, Chen, Shuangcheng, additional, Pu, Mingbo, additional, Jiang, Ning, additional, Qiu, Kun, additional, Lavery, Martin P. J., additional, Abbas, Hasan T., additional, and Luo, Xiangang, additional

Published
2023
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