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462 results on '"Zhang Yaoming"'

3. A New Space-Time RBF Method for Reaction Diffusion and Wave Propagation Problems

Author

Zhang, Chao, Fu, Zhuojia, Zhang, Yaoming, Ceccarelli, Marco, Series Editor, Agrawal, Sunil K., Advisory Editor, Corves, Burkhard, Advisory Editor, Glazunov, Victor, Advisory Editor, Hernández, Alfonso, Advisory Editor, Huang, Tian, Advisory Editor, Jauregui Correa, Juan Carlos, Advisory Editor, Takeda, Yukio, Advisory Editor, and Li, Shaofan, editor

Published
2024
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13. Filtering electrons by mode coupling in finite semiconductor superlattices

Author

Luo, Xiaoguang, Shi, Jian, Zhang, Yaoming, Niu, Ziang, Miao, Dongpeng, Mi, Huiru, and Huang, Wei

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Electron transmission through semiconductor superlattices is studied with transfer matrix method and resonance theory. The formation of electron band-pass transmission is ascribed to the coupling of different modes in those semiconductor superlattices with the symmetric unit cell. Upon Fabry-P\'erot resonance condition, Bloch modes and two other resonant modes are identified to be related to the nature of the superlattice and its unit cell, respectively. The bands related to the unit cell and the superlattice overlap spontaneously in the tunneling region due to the shared wells, and the coupling of perfectly resonances results in the band-pass tunneling. Our findings provide a promising way to study electronic systems with more complicated superlattices or even optical systems with photonic crystals., Comment: 15 pages, 4 figures

Published
2021
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23. Some nonlinear delay integral inequalities on time scales arising in the theory of dynamics equations

Author

Zhang Yaoming, Zheng Bin, Zhou Jinchuan, Feng Qinghua, and Meng Fanwei

Subjects
delay integral inequality, time scales, dynamic equation, bound, Mathematics, QA1-939
Abstract

Abstract In this paper, some new nonlinear delay integral inequalities on time scales are established, which provide a handy tool in the research of boundedness of unknown functions in delay dynamic equations on time scales. The established results generalize some of the results in Lipovan [J. Math. Anal. Appl. 322, 349-358 (2006)], Pachpatte [J. Math. Anal. Appl. 251, 736-751 (2000)], Li [Comput. Math. Appl. 59, 1929-1936 (2010)], and Sun [J. Math. Anal. Appl. 301, 265-275 (2005)]. MSC 2010: 26E70; 26D15; 26D10.

Published
2011

24. Generalized Gronwall-Bellman-type discrete inequalities and their applications

Author

Meng Fanwei, Feng Qinghua, and Zhang Yaoming

Subjects
Discrete inequalities, Difference equations, Explicit bounds, Qualitative analysis, Quantitative analysis, Mathematics, QA1-939
Abstract

Abstract In this paper, some new nonlinear Gronwall-Bellman-type discrete inequalities are established, which can be used as a handy tool in the research of qualitative and quantitative properties of solutions of certain difference equations. The established results generalize some of the recent results obtained by Cheung and Ma, respectively. Mathematics Subject Classification (2010) 26D15

Published
2011

25. Some new finite difference inequalities arising in the theory of difference equations

Author

Meng Fanwei, Feng Qinghua, and Zhang Yaoming

Subjects
Finite difference inequalities, Difference equations, Explicit bounds, Qualitative analysis, Quantitative analysis, Mathematics, QA1-939
Abstract

Abstract In this work, some new finite difference inequalities in two independent variables are established, which can be used in the study of qualitative as well as quantitative properties of solutions of certain difference equations. The established results extend some existing results in the literature. MSC 2010: 26D15

Published
2011

38. Super‐Durable, Tough Shape‐Memory Polymeric Materials Woven from Interlocking Rigid‐Flexible Chains.

Author

Xu, Jing, Shao, Mingchao, Chen, Tianze, Li, Song, Zhang, Yaoming, Yang, Zenghui, Zhang, Nan, Zhang, Xinrui, Wang, Qihua, and Wang, Tingmei

Subjects
FATIGUE limit, COPPER, POLYURETHANES, WEAVING, POLYIMIDES, SHAPE memory polymers, POLYMERS
Abstract

Developing advanced engineering polymers that combine high strength and toughness represents not only a necessary path to excellence but also a major technical challenge. Here for the first time a rigid‐flexible interlocking polymer (RFIP) is reported featuring remarkable mechanical properties, consisting of flexible polyurethane (PU) and rigid polyimide (PI) chains cleverly woven together around the copper(I) ions center. By rationally weaving PI, PU chains, and copper(I) ions, RFIP exhibits ultra‐high strength (twice that of unwoven polymers, 91.4 ± 3.3 MPa), toughness (448.0 ± 14.2 MJ m−3), fatigue resistance (recoverable after 10 000 cyclic stretches), and shape memory properties. Simulation results and characterization analysis together support the correlation between microstructure and macroscopic features, confirming the greater cohesive energy of the interwoven network and providing insights into strengthening toughening mechanisms. The essence of weaving on the atomic and molecular levels is fused to obtain brilliant and valuable mechanical properties, opening new perspectives in designing robust and stable polymers. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Strengthening‐Durable Trade‐Off and Self‐Healing, Recyclable Shape Memory Polyurethanes Enabled by Dynamic Boron–Urethane Bonds.

Author

Zhang, Qingxiang, Yang, Jing, Cao, Pengrui, Gong, Junhui, Tang, Zhangzhang, Zhou, Kai, Luo, Heming, Zhang, Xinrui, Wang, Tingmei, Chen, Shoubing, Pei, Xianqiang, Wang, Qihua, and Zhang, Yaoming

Subjects
SHAPE memory polymers, DYNAMIC mechanical analysis, WASTE recycling, COVALENT bonds, REINFORCEMENT (Psychology)
Abstract

Addressing the demand for integrating strength and durability reinforcement in shape memory polyurethane (SMPU) for diverse applications remains a significant challenge. Here a series of SMPUs with ultra‐high strength, self‐healing and recyclability, and excellent shape memory properties through introducing dynamic boron–urethane bonds are synthesized. The introducing of boric acid (BA) to polyurethane leading to the formation of dynamic covalent bonds (DCB) boron–urethane, that confer a robust cross‐linking structure on the SMPUs led to the formation of ordered stable hydrogen‐bonding network within the SMPUs. The flexible crosslinking with DCB represents a novel strategy for balancing the trade‐off between strength and durability, with their strengths reaching up to 82.2 MPa while also addressing the issue of durability in prolonged usage through the provision of self‐healing and recyclability. The self‐healing and recyclability of SMPU are demonstrated through rapid dynamic exchange reaction of boron–urethane bonds, systematically investigated by dynamic mechanical analysis (DMA). This study sheds light on the essential role of such PU with self‐healing and recyclability, contributing to the extension of the PU's service life. The findings of this work provide a general strategy for overcoming traditional trade‐offs in preparing SMPUs with both high strength and good durability. [ABSTRACT FROM AUTHOR]

Published
2024
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