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26 results on '"Zhang, Zhonglin"'

5. Numerical Studies on the Nonlinear Coupling in Atmospheric Dual Radio-Frequency Dielectric Barrier Discharge

Author

B. H. Jiang, Zhenhua Wang, Zhang Zhonglin, and Qiuyue Nie

Subjects
Electron density, Materials science, Plasma parameters, Ionization, Charge density, Dielectric barrier discharge, Plasma, Electron, Atomic physics, Electron ionization
Abstract

Dielectric barrier discharges (DBD) as a common method to generate plasmas with high density, low gas temperature, and abundant active particle under atmospheric pressure have been widely investigated in the past decades. Among these researches, the investigation on plasma parameters modulation represents a novel and budding focus. According to our previous works of DBD driven by dual-frequency, it has been demonstrated to provide a possible approach of controlling both averaged electron density and gas temperature independently based on the nonlinear frequency coupling effect. In this work, we used one-dimensional fluid model with semi-kinetic method, systemically studied the nonlinear behavior of the dual radio-frequency driven DBD. In term of the results of effective electron energy distribution function (EEDF) and electron impact ionization rate, it is found that the variations of power density and phase relationship provide separate control over the electron density, mean electron energy and gas temperature. Moreover, mode transitions are discussed in this paper. It is shown that there exist three kinds of discharge modes, which are governed by the nonlinear dynamics in the plasma sheath. Among which, the ionization in α mode is determined by the nonlinear coupling electron heating and local momentary charge density. While in γ mode, the ionization is caused mainly by the electron avalanches. In summary, the dual radio-frequency applied in DBD system is found to generate a nonlinear synergistic effect between two frequencies, which can provide a possible approach to enhance control over the plasma parameters.

Published
2017

6. Study on the Magnetic Forces of the Dipole in the SPERF.

Author

E, Peng, Ling, Wenbin, Mao, Aohua, Xiao, Qingmei, Guan, Jian, and Zhang, Zhonglin

Subjects
MAGNETISM, MAGNETIC dipoles, PLASMA physics, SPACE plasmas, SYMMETRY breaking, EDDY currents (Electric)
Abstract

The Space Plasma Environment Research Facility (SPERF) in Harbin, China, is a user facility dedicated to studying space plasma physics on ground. Magnetic forces are critical to the reliable operation of a magnetic system. A dipole magnet plays a central role in the system and its force conditions are extremely complicated. So, the magnetic force of the dipole magnet is studied in this article. The magnetic system is first introduced. Then, the virtual work principle is presented to evaluate the force analytically. Not dedicated to the complex analytical computation, the qualitative analysis is done based on the breaking of the symmetry of the system from the perspective of the dipole. To validate the qualitative results and solve the force precisely, the finite-element analysis in ANSYS Maxwell is performed. The force results are analyzed and regular patterns are obtained. The influence of the spatial position and the eddy current are studied. In a complex system, the dipole forces from different source magnets compete to dominate as the time proceeds. The methods for analyzing the magnetic forces can easily be extended to other electromagnetic systems. [ABSTRACT FROM AUTHOR]

Published
2020
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7. Analysis of the Impact of Reservoir Water Level Fluctuation on the Stability of Cohesive Colluvial Landslide in the Three Gorges Reservoir Area

Author

Qiang Yang, Weicui Ding, Youlong Gao, Zhang Zhonglin, Shuhua Pan, and Li Qiang

Subjects
Water resources, Petroleum seep, Hydrostatic pressure, Geotechnical engineering, Landslide, Stability (probability), Geology, Test data, Three gorges, Colluvium
Abstract

Based on the test data, survey data and the real-time monitoring data, this paper makes the Tangjiao #1 cohesive landslide in Three Gorges Area to be the research object, analyzing and studying the impact of reservoir water level fluctuation rates on stability of typical cohesive colluvial landslide with the help of the SEEP/W and SLOPE/W of Geoscience software GeoStudio. The results show that the impact of changing reservoir level on reservoir landslide stability is controlled by a variety of factors, including the hydrodynamic pressure, hydrostatic pressure, and uplift force, physical and mechanical properties (c, φ value change) and the stability trend depends on the dominant factor(s).

Published
2013

10. The Removal of EOG Artifacts From EEG Signals Using Independent Component Analysis and Multivariate Empirical Mode Decomposition.

Author

Wang, Gang, Teng, Chaolin, Li, Kuo, Zhang, Zhonglin, and Yan, Xiangguo

Subjects
ELECTROENCEPHALOGRAPHY, HILBERT-Huang transform, INDEPENDENT component analysis, DATA extraction, SIGNAL-to-noise ratio
Abstract

The recorded electroencephalography (EEG) signals are usually contaminated by electrooculography (EOG) artifacts. In this paper, by using independent component analysis (ICA) and multivariate empirical mode decomposition (MEMD), the ICA-based MEMD method was proposed to remove EOG artifacts (EOAs) from multichannel EEG signals. First, the EEG signals were decomposed by the MEMD into multiple multivariate intrinsic mode functions (MIMFs). The EOG-related components were then extracted by reconstructing the MIMFs corresponding to EOAs. After performing the ICA of EOG-related signals, the EOG-linked independent components were distinguished and rejected. Finally, the clean EEG signals were reconstructed by implementing the inverse transform of ICA and MEMD. The results of simulated and real data suggested that the proposed method could successfully eliminate EOAs from EEG signals and preserve useful EEG information with little loss. By comparing with other existing techniques, the proposed method achieved much improvement in terms of the increase of signal-to-noise and the decrease of mean square error after removing EOAs. [ABSTRACT FROM AUTHOR]

Published
2016
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