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1,504 results on '"Wang, Yanqiu"'

2. An arbitrary order locking-free weak Galerkin method for linear elasticity problems based on a reconstruction operator

Author

Huo, Fuchang, Wang, Ruishu, Wang, Yanqiu, and Zhang, Ran

Subjects
Mathematics - Numerical Analysis, 65N30, 65N15, 74S05, 35J50, 74B05
Abstract

The weak Galerkin (WG) finite element method has shown great potential in solving various type of partial differential equations. In this paper, we propose an arbitrary order locking-free WG method for solving linear elasticity problems, with the aid of an appropriate $H(div)$-conforming displacement reconstruction operator. Optimal order locking-free error estimates in both the $H^1$-norm and the $L^2$-norm are proved, i.e., the error is independent of the $Lam\acute{e}$ constant $\lambda$. Moreover, the term $\lambda\|\nabla\cdot \mathbf{u}\|_k$ does not need to be bounded in order to achieve these estimates. We validate the accuracy and the robustness of the proposed locking-free WG algorithm by numerical experiments.

Published
2023

5. A Locking-Free Weak Galerkin Finite Element Method for Linear Elasticity Problems

Author

Huo, Fuchang, Wang, Ruishu, Wang, Yanqiu, and Zhang, Ran

Subjects
Mathematics - Numerical Analysis, Primary 65N30, 65N15, 74S05, Secondary 35J50, 74B05
Abstract

In this paper, we introduce and analyze a lowest-order locking-free weak Galerkin (WG) finite element scheme for the grad-div formulation of linear elasticity problems. The scheme uses linear functions in the interior of mesh elements and constants on edges (2D) or faces (3D), respectively, to approximate the displacement. An $H(div)$-conforming displacement reconstruction operator is employed to modify test functions in the right-hand side of the discrete form, in order to eliminate the dependence of the $Lam\acute{e}$ parameter $\lambda$ in error estimates, i.e., making the scheme locking-free. The method works without requiring $\lambda \|\nabla\cdot \mathbf{u}\|_1$ to be bounded. We prove optimal error estimates, independent of $\lambda$, in both the $H^1$-norm and the $L^2$-norm. Numerical experiments validate that the method is effective and locking-free.

Published
2023

6. Effect of Ultrasonic Treatment on the Structural and Oxidation Properties of Chicken Myofibrillar Protein under Low-Salt Conditions

Author

LI Ke, ZHANG Yixue, WANG Yanqiu, ZHAO Dianbo, ZHAO Yingying, CHEN Bo, WANG Yu, DU Manting, BAI Yanhong

Subjects
ultrasound, myofibrillar protein, low salt, oxidation, structural characteristics, free radicals, Food processing and manufacture, TP368-456
Abstract

In order to investigate the effect of ultrasound on the structure and physical stability of chicken myofibrillar protein (MP) under low-salt conditions (0.15 mol/L NaCl), as well as the oxidizing effect of free radicals generated by ultrasound on MP, this study investigated the changes in the structure and oxidative properties of MP under low-salt conditions after ultrasound treatments (20 kHz, 450 W for 0, 3, 6, 9, and 12 min). The results showed that compared with the control group, the solubility, physical stability, and absolute ζ-potential of MP under low-salt conditions increased significantly (P < 0.05) with ultrasonic treatment time, whereas the turbidity and particle size decreased significantly (P < 0.05). The solubility was increased to 58.5% after 12 min of ultrasonic treatment. After ultrasonic treatment, the surface hydrophobicity and molecular flexibility were significantly increased, indicating that ultrasonic treatment caused the highly aggregated structure of myofibrillar protein to unfold and the internal hydrophobic groups to be exposed under low-salt conditions. After ultrasonic treatment for more than 6 min, the free sulfhydryl content of MP began to gradually decrease, whereas the content of disulfide bonds increased. After ultrasonic treatment for 12 min, the contents of free radicals, carbonyl groups and dimerized tyrosine (by 20.55%) were significantly increased (P < 0.05), while the free amino group content was decreased significantly (P < 0.05). In conclusion, ultrasonic treatment changed the structural properties of MP under low-salt conditions and increased its physical stability, thereby contributing to the formation of emulsions. Ultrasonic treatment can generate free radicals; ultrasonic treatment time for 6 min can exacerbate the oxidation of MP. So, attention should be paid to the oxidizing effect of free radicals generated by ultrasound on MP when applying ultrasonic treatment to improve the functional properties of MP.

Published
2024
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7. Chess-board Acoustic Crystals with Momentum-space Nonsymmorphic Symmetries

Author

Wang, Yanqiu, Zhang, Chen, Chen, Z. Y., Liang, Bin, Zhao, Y. X., and Cheng, Jianchun

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Applied Physics
Abstract

Spatial symmetries appearing in both real and momentum space are of fundamental significance to crystals. However, in the conventional framework, every space group in real space, either symmorphic or nonsymmorphic, corresponds to a symmorphic dual in momentum space. Our experiment breaks the framework by showing that in a 2D acoustic crystal with chess-board pattern of $\pi$ and 0 fluxes, mirror reflections are manifested nonsymmorphically as glide reflections in momentum space. These momentum-space nonsymmorphic symmetries stem from projective, rather than ordinary, representations of the real-space symmetries due to the peculiar flux pattern. Moreover, our experiment demonstrates that the glide reflection can reduce the topological type of the Brillouin zone from the torus to the Klein bottle, resulting in novel topological phases with new topological invariants. Since crystalline topologies are based on momentum-space symmetries, our work paves the way for utilizing engineerable gauge fluxes over artificial crystals to extend the current topological classifications into the broader regime of momentum-space nonsymmorphic symmetries., Comment: 12 pages,3 figures

Published
2023

12. Deep learning on tertiary lymphoid structures in hematoxylin-eosin predicts cancer prognosis and immunotherapy response

Author

Chen, Ziqiang, Wang, Xiaobing, Jin, Zelin, Li, Bosen, Jiang, Dongxian, Wang, Yanqiu, Jiang, Mengping, Zhang, Dandan, Yuan, Pei, Zhao, Yahui, Feng, Feiyue, Lin, Yicheng, Jiang, Liping, Wang, Chenxi, Meng, Weida, Ye, Wenjing, Wang, Jie, Qiu, Wenqing, Liu, Houbao, Huang, Dan, Hou, Yingyong, Wang, Xuefei, Jiao, Yuchen, Ying, Jianming, Liu, Zhihua, and Liu, Yun

Published
2024
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21. A Weak Galerkin Mixed Finite Element Method for second order elliptic equations on 2D Curved Domains

Author

Liu, Yi, Chen, Wenbin, and Wang, Yanqiu

Subjects
Mathematics - Numerical Analysis, Mathematics - Analysis of PDEs
Abstract

This article concerns the weak Galerkin mixed finite element method (WG-MFEM) for second order elliptic equations on 2D domains with curved boundary. The Neumann boundary condition is considered since it becomes the essential boundary condition in this case. It is well-known that the discrepancy between the curved physical domain and the polygonal approximation domain leads to a loss of accuracy for discretization with polynomial order $\alpha>1$. The purpose of this paper is two-fold. First, we present a detailed error analysis of the original WG-MFEM for solving problems on curved domains, which exhibits an $O(h^{1/2})$ convergence for all $\alpha\ge 1$. It is a little surprising to see that even the lowest-order WG-MFEM ($\alpha=1$) experiences a loss of accuracy. This is different from known results for the finite element method (FEM) or the mixed FEM, and appears to be a combined effect of the WG-MFEM design and the fact that the outward normal vector on the polygonal approximation domain is different from the one on the curved domain. Second, we propose a remedy to bring the approximation rate back to optimal by employing two techniques. One is a specially designed boundary correction technique. The other is to take full advantage of the nice feature that weak Galerkin discretization can be defined on polygonal meshes, which allows the curved boundary to be better approximated by multiple short edges without increasing the total number of mesh elements. Rigorous analysis shows that a combination of the above two techniques renders optimal convergence for all $\alpha$. Numerical results further confirm this conclusion.

Published
2022
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45. Dynamics simulation research on fault conditions of deflecting to airflow flap mechanism of civil aircraft

Author

FENG Yunwen, HE Zhiyu, TANG Jiaqiang, XUE Xiaofeng, and WANG Yanqiu

Subjects
high-lift device, rigid-fiexible coupling, dynamic simulation, fault simulation, Motor vehicles. Aeronautics. Astronautics, TL1-4050
Abstract

The deflecting to airflow flap of civil aircraft are generally driven by complex multi-hinge mechanisms in space. According to the requirements of the airworthiness clause CCAR25.671, it is necessary to carry out research on the mechanism characteristics under typical faults. Firstly, a digital prototype of the mechanism motion is constructed, and the hinge point of the rigid multi-hinge mechanism is associated with the flexible flap body by using the RBE2 unit, and the rigid-flexible coupling dynamic model of the flap mechanism is established. Then, under three aerodynamic load conditions of cruise, take-off and landing, two typical faults, hinge jamming and one-side failure of control system, are simulated by adjusting the hinge friction coefficient and setting one-side driving failure. Finally, the variation law of driving torque and hinge point load is analyzed. The results show that:when the hinge is stuck, the inner drive link ear piece is stretched and damaged; when the inner drive fails, the radial load at the hinge point of the outer rocker arm increases significantly. In practice, we should focus on the middle joint of the outer rocker arm of this type of flap. The radial and axial load-bearing capacity of the bearing avoids the situation of separate manipulation of the outer mechanism, and at the same time, it is necessary to increase the torque protection for the entire drive system.

Published
2023
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