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22 results on '"Yue, Yunfei"'

2. Modulation instability, conservation laws and localized waves for the generalized coupled Fokas-Lenells equation

Author

Yue, Yunfei and Chen, Yong

Subjects
Nonlinear Sciences - Exactly Solvable and Integrable Systems, Nonlinear Sciences - Pattern Formation and Solitons
Abstract

This paper focuses on the modulation instability, conservation laws and localized wave solutions of the generalized coupled Fokas-Lenells equation. Based on the theory of linear stability analysis, distribution pattern of modulation instability gain G in the (K,k) frequency plane is depicted, and the constraints for the existence of rogue waves are derived. Subsequently, we construct the infinitely many conservation laws for the generalized coupled Fokas-Lenells equation from the Riccati-type formulas of the Lax pair. In addition, the compact determinant expressions of the N-order localized wave solutions are given via generalized Darboux transformation, including higher-order rogue waves and interaction solutions among rogue waves with bright-dark solitons or breathers. These solutions are parameter controllable: (m_i,n_i) and (\alpha,\beta) control the structure and ridge deflection of solution respectively, while the value of |d| controls the strength of interaction to realize energy exchange. Especially, when d=0, the interaction solutions degenerate into the corresponding order of rogue waves., Comment: 21 pages, 10 figures

Published
2021

3. Modulation instability, rogue waves and spectral analysis for the sixth-order nonlinear Schrodinger equation

Author

Yue, Yunfei, Huang, Lili, and Chen, Yong

Subjects
Nonlinear Sciences - Exactly Solvable and Integrable Systems, Nonlinear Sciences - Pattern Formation and Solitons
Abstract

Modulation instability, rogue wave and spectral analysis are investigated for the nonlinear Schrodinger equation with the higher-order terms. The modulation instability distribution characteristics from the sixth-order to the eighth-order nonlinear Schrodinger equations are studied. Higher-order dispersion terms are closely related to the distribution of modulation stability regime, and n-order dispersion term corresponds to $n-2$ modulation stability curves in the modulation instability band. Based on the generalized Darboux transformation method, the higher-order rational solutions are constructed. Then the compact algebraic expression of the Nth-order rogue wave is given. Dynamic phenomena of first- to third-order rogue waves are illustrated, which exhibit meaningful structures. Two arbitrary parameters play important roles in the rogue wave solution. One can control deflection of crest of rogue wave and its width, while the other can cause the change of width and amplitude of rogue wave. When it comes to the third-order rogue wave, three typical nonlinear wave constructions, namely fundamental, circular and triangular are displayed and discussed. Through the spectral analysis on first-order rogue wave, when these parameters satisfy certain conditions, it occurs a transition between W-shaped soliton and rogue wave., Comment: 17 pages, 10 figures

Published
2019
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9. GLP-1(7-36) inhibits atherosclerosis progression in ApoE-/- mouse aorta by lowering expressions of CD36 and ACAT1 in foam cells

Author

HAN Yongkui, YUE Yunfei, ZHANG Kui, and SHEN Xiaoyu

Subjects
glucagon-like peptide-1, atherosclerosis, acat1, cd36, Medicine (General), R5-920
Abstract

Objective To investigate whether glucagon-like peptide-1 (GLP-1) (7-36) inhibits the progression of aortic atherosclerotic plaque in ApoE knockout (ApoE-/-) mice fed with high-fat diet and the effect of GLP-1 (7-36) on the expressions of CD36 and acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1) in macrophage-derived foam cells. Methods Forty male ApoE-/- mice (6-8 weeks old, weighing 18-20 g) were randomized equally into normal diet group, high-fat diet (model) group, GLP-1 (7-36) group, and GLP-1 (7-36)+Exendin (9-39) group. The area of the atherosclerotic plaque in the aortic root of the mice was determined using HE staining, oil red O staining, and immunohistochemical staining with CD36 and ACAT1 antibodies. In the cell experiment, the macrophages (RAW264.7 cells) were induced with oxidized low-density lipoprotein (ox-LDL) and treated with different concentrations of GLP-1 (7-36), alone or in combination with Exendin (9-39). The expressions of CD36 and ACAT1 mRNAs and proteins in the cells was detected using RT-PCR and Western blotting, respectively. The levels of total cholesterol (TC), free cholesterol (FC) and cholesterol ester (CE) in the cells were detected using high-performance liquid chromatography, and immunofluorescence analysis was performed to detect the expressions of CD36 and ACAT1 receptor proteins. Results Compared with the control mice, ApoE-/- mice on high-fat diet showed significantly higher expression levels of CD36 and ACAT1 at both the mRNA and protein levels in the aortic atherosclerotic plaques (P < 0.05). CD36 and ACAT1 expressions in the plaques were significantly lowered by treatment of the mice with GLP-1 (7-36) (P < 0.05); the expression levels of CD36 and ACAT1 were significantly higher in GLP-1+Exendin group than in GLP-1 group (P < 0.05). HE and oil red O staining showed that in the model group, the mean proportion of the plaque area in the aortic intimal area was (30.3±3.8)%, which was significantly lowered to (15.1±4.3)% in GLP-1 group (P < 0.05); the ratio of the plaque area was (25.7±3.4)% in GLP-1+Exendin group, where significantly more numerous atherosclerotic plaques were observed below the intima as compared with GLP-1 group (P < 0.05). GLP-1 (7-36) significantly decreased the percentage of CD36- and ACAT1-positive cells in the aorta of the mice (P < 0.05). Conclusion GLP-1 can reduce the accumulation of intracellular cholesterol by inhibiting the expression of CD36 and ACAT1 to suppress the foaming of macrophages, and thus inhibits the formation of atherosclerotic plaques.

Published
2019
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16. A Method for Small Leak Precise Location in Pressure Piping by Acoustic Emission

Author

Yue Yunfei, Yongmei Hao, Ni Qin, and Yan Xinming

Subjects
Leak, Wavelet, Acoustic emission, Noise (signal processing), Acoustics, Dispersion (optics), Signal, Geology, Continuous wavelet transform, Computer Science::Cryptography and Security, Time–frequency analysis
Abstract

Due to leak location of acoustic emission (AE) signal affected by the surrounding noise and the signal with the dispersion and multimode characteristics in communication channels in pipeline, it is not accurate to use traditional AE technique for leak location. In this paper, scale analysis of AE signal de-noising by wavelet and the wavelet scales for selected db1, the horizontal level, is six layers. The continuous wavelet transform is used to analyze AE signal at time frequency and combined with modal acoustic emission (MAE) technique to reduce the impact of dispersion characteristics in signals. Finally, the exact position of the leak source is calculated by using the one-dimensional linear located formula. The experiment proved effectiveness of the method, making the positioning error of about 4%.

Published
2019

20. Research on Gas Pipeline Multi-Point Leak Signal Processing and Source Locating Using VMD, BSS and Relative Entropy

Author

Xing Zhixiang, Wu Yujia, Hao Yongmei, Ni Qin, and Yue Yunfei

Subjects
Leak, Signal processing, Kullback–Leibler divergence, Computer science, business.industry, Acoustics, 020206 networking & telecommunications, 02 engineering and technology, Gas pipeline, Computer Science::Hardware Architecture, Artificial Intelligence, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Computer Vision and Pattern Recognition, Artificial intelligence, Environmental noise, business, Software, Signal interference, Multi point, Leakage (electronics)
Abstract

The early multi-point leakage source signals of urban gas pipeline are weak and can be easily affected by environmental noise and signal interference between adjacent sources, which causes large leakage positioning error. In this paper, an integrated signal processing method combining VMD, BSS and Relative entropy for multi-point pipeline leakage signal and source positioning is presented. Firstly, VMD and Relative entropy were employed to obtain effective IMF mode components and their features during the decomposition for pipeline leakage signal. Relative entropy was used to improve signal-to-noise ratio and extract the features of leakage signal. Then, BSS was used to decompose multi-point mixed leakage signals so as to obtain independent signal components. Finally, the time difference and wave velocity were, respectively, obtained by calculating the time domain distribution of the independent signal components and the main modal guided wave, so the precise positioning of the pipeline leakage was realized. The results show that the combined method proposed can not only select and extract leakage signal adaptively but also separate single independent signal from multi-point mixed signal, which helps to locate pipeline multi-point leakage sources more accurately.

Published
2019

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