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151 results on '"Xu Jingfeng"'

16. Investigation on the Static Performance of Surface-Throttling Frictionless Pneumatic Cylinder through Finite Element Method.

Author

Xu, Jingfeng, Gao, Siyu, Qi, Lizi, Gao, Qiang, Zhu, Min, Yang, Hongbin, Li, Yinze, Wei, Wenyuan, and Lu, Lihua

Subjects
AIR cylinders, FINITE element method, COMPUTATIONAL fluid dynamics, EQUILIBRIUM
Abstract

The equilibrium system is essential for the high-precision movement of the ultra-precision vertical axis. However, the complex assembly process makes orifice-throttling frictionless cylinders difficult to manufacture and prone to air hammering. Surface-throttling frictionless pneumatic cylinders effectively avoid these problems. This paper establishes an improved finite element method (FEM) model of a novel surface-throttling frictionless pneumatic cylinder to investigate its static performance. Furthermore, the static equilibrium calculation of the dual-cylinder system is concerned. The radial bearing capacity and support force requirements for the surface-throttling aerostatic bearings are obtained. The outcomes provide theoretical guidance for optimizing cylinder parameters. It ensures that the ultimately optimized cylinder meets the requirements for radial bearing capacity and support force of the ultra-precision vertical axis while minimizing air consumption. Finally, the accuracy of the proposed method is verified through computational fluid dynamics (CFD) calculation and experiments. [ABSTRACT FROM AUTHOR]

Published
2024
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25. Efficient and de-noising calculation for extracting impulse response function in time-domain

Author

Yong Wang, Lu Yimin, Haozheng Wei, Chen Enwei, Xu Jingfeng, and Xiao Hui

Subjects
0209 industrial biotechnology, Frequency response, 020901 industrial engineering & automation, Computer science, 020208 electrical & electronic engineering, De noising, 0202 electrical engineering, electronic engineering, information engineering, General Engineering, 02 engineering and technology, Time domain, Algorithm, Impulse response
Abstract

Impulse response function (IRF) and frequency response function (FRF) are the bases and preconditions for acquiring the parameters of a dynamic system and accurately obtaining the dynamic response ...

Published
2021

39. Reinsurance strategy and network contagion: a macroprudential perspective.

Author

Li, Fei, Li, Bingqing, and Xu, Jingfeng

Subjects
REINSURANCE, FINANCIAL policy, FINANCIAL planning, ECONOMIC sectors, SYSTEMIC risk (Finance)
Abstract

This article develops a network-based contagion model to investigate reinsurance strategy from a macroprudential perspective. We analyse the impact of reinsurance strategy on the spillovers from insurance sector to other economic sectors when a catastrophe such as a series of coronavirus-related claims occurs. The risk diversification level of the reinsurance strategy shows nonmonotonic effects on risk spillovers. When the diversified level is high enough relative to the actual magnitude of catastrophe, the spillover effect will not occur. However, when not sufficiently diversified, spillover effect is unavoidable and the diversified level shows a U-shaped relation with economic losses caused by risk spillovers. Our results thus reveal a new reinsurance insight for policymakers and regulators to develop macroprudential policy for managing systemic risk. [ABSTRACT FROM AUTHOR]

Published
2022
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46. Performance Simulation and Experimental Verification of Fast Broadband MVDR Algorithm

Author

Li Haitao, Jiang Bin, Li Zhizhong, Yang Gang, and Xu Jingfeng

Subjects
Background noise, Beam diameter, Computer simulation, Basis (linear algebra), Detection threshold, Computer science, Monte Carlo method, Broadband, Algorithm, Directivity
Abstract

In order to promote the application of fast broadband MVDR algorithm in engineering, the performance of it is studied by simulation analysis and experimental data validation. On the basis of analysis of the principle of fast MVDR algorithm, Monte Carlo numerical simulation method was used to analyze the directivity curve, beam width and detection threshold of the MVDR algorithm. The actual data at sea was used to verify the validity. The results show that the performance of fast MVDR algorithm is better than CBF algorithm under the condition of high SNR, and it has narrow beam width and strong background noise suppression ability. Its performance is similar to CBF algorithm under the condition of low SNR. Its detection ability is almost the same as that of CBF algorithm in incoherent background noise. MVDR algorithm is suitable for high resolution target detection in high SNR condition.

Published
2019

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