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Terminal sliding mode control based on super-twisting algorithm

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Journal of Systems Engineering and Electronics 2017年第1期28卷 145-150页

作者： Zhanshan Zhao Hongru gu jing Zhang Gang Ding School of Computer Science and Software Engineering Tianjin Polytechnic UniversityTianjin 300387China School of Textiles Tianjin Polytechnic UniversityTianjin 300387China Tianjin Vocational Institute Tianjin 300410China Tianjin Radio&TV University Tianjin 300191China

An improved non-singular terminal sliding mode control based on the super-twisting algorithm is proposed for a class of second-order uncertain nonlinear systems. This method can effectively avoid the singularity problem and obviously reduce the chattering phenomenon. The stability of the proposed procedure is proven to be finite-time convergence using the Lyapunov theory against uncertain unmodeled dynamic and external disturbances. An example is given to show the proposed improved non-singular terminal sliding mode control (SMC) law effectively. © 1990-2011 Beijing Institute of Aerospace Information.

关键词： Nonlinear control systems Nonlinear systems

Covering α-Fe2O3 protection layer on the surface of p-Si micropillar array for enhanced photoelectrochemical performance

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Frontiers of Environmental Science & Engineering 2017年第6期11卷 119-127页

作者： jing gu Hongtao Yu Xie Quan Shuo Chen Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education) School of Environmental Science and Technology Dalian University of Technology Dalian 116024 China

The spontaneous oxidation process of pristine silicon （Si） limits its application as photocatalyst or electrode in aqueous solution or moist air. Covering a protection layer on Si surface is an effective approach to overcome this disadvantage. In this paper, α-Fe2O3 is demonstrated to be an excellent alternative as a protection material, α-Fe2O3 layer was deposited around each p-type Si micropillar （SiMP） in well-ordered array by chemical bath ＂deposition ＂method. The diameter of SiMP was 3 μm and the thickness of α-Fe2O3 layer was about 20 nm. The photoeletrochemical stability of SiMP/α-Fe2O3 was proved by 10 circles cyclic voltammetr7 testing. Compared with SiMP, its optical absorption and photocurrent density improved 2 times and 4 times, respectively, and its onset potential for hydrogen evolution moved positively about 0.4 V. These improved performances could be ascribed to the enhanced photogenemted-charge-separation efficiency deriving from built-in electric field at the interface between Si and α-Fe2O3. The above results show an effective strategy to utilize Si material as photocatalyst or electrode in aqueous solution or moist air.

关键词： Si α-Fe2O3 Photoelectrochemistry Photogenemted charge separation

Effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging

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International Journal of Minerals,Metallurgy and Materials 2015年第7期22卷 721-728页

作者： Wei gu jing-yuan Li Yi-de Wang School of Materials Science and Engineering University of Science and Technology Beijing

The effect of dislocation structure evolution on low-angle grain boundary formation in 7050 aluminum alloy during aging was studied by using optical microscopy, transmission electron microscopy, and electron backscatter diffraction analysis of misorientation angle distribution, cumulative misorientation and geometrically necessary dislocation （GND） density. Experimental results indicate that coarse spindle-shaped grains with the dimension of 200 μm- 80 μm separate into fine equiaxed grains of 20μm in size as a result of newborn low-angle grain boundaries formed during the aging process. More specifically, the dislocation arrays, which are rearranged and formed due to scattered dislocations during earlier quenching, transform into low-angle grain boundaries with aging time. The relative frequency of 3°-5° low-angle grain boundaries increases to over 30%. The GND density, which describes low-angle grain boundaries with the misorientation angle under 3°, tends to decrease during initial aging. The inhomogeneous distribution of GNDs is affected by grain orientation. A decrease in GND density mainly occurs from 1.83 × 10^13 to 4.40 × 10^11 m^-2 in grains with 〈111〉 fiber texture. This is consistent with a decrease of unit cumulative misorientation. Precipitation on grain boundaries and the formation of a precipitation free zone （PFZ） are facilitated due to the eroding activity of the Graft etchant. Consequently, low-angle grain boundaries could be readily viewed by optical microscopy due to an increase in their electric potential difference.

关键词： aluminum alloys low-angle grain boundaries dislocation structure aging dislocation density

Cryptanalysis of Key Exchange Protocol Based on Tensor Ergodic Problem

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China Communications 2018年第10期15卷 172-181页

作者： Chunsheng gu Youyu gu Peizhong Shi Chunpeng Ge Zhenjun jing School of Computer Engineering Jiangsu University of Technology State Key Laboratory of Information Security Institute of Information Engineering Chinese Academy of Sciences School of Mathematics Hefei University of Technology

Recently, Mao, Zhang, Wu et al. constructed two key exchange(KE) protocols based on tensor ergodic problem(TEP). Although they conjectured that these constructions can potentially resist quantum computing attack, they did not provide a rigorous security proof for their KE protocols. In this paper, applying the properties of ergodic matrix, we first present a polynomial time algorithm to solve the TEP problem using O(n^6) arithmetic operations in the finite field, where n is the security parameter. Then, applying this polynomial time algorithm, we generate a common shared key for two TEP-based KE constructions, respectively. In addition, we also provide a polynomial time algorithm with O(n^6) arithmetic operations that directly recovers the plaintext from a ciphertext for the KE-based encryption scheme. Thus, the TEP-based KE protocols and their corresponding encryption schemes are insecure.

关键词： key exchange KE-based encryption tensor decomposition ergodic matrix

An adaptive fuzzy filter for coding artifacts removal in video and image

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第6期8卷 841-848页

作者： WU jing YE Xiu-qing gu Wei-kang Department of Information and Communication Engineering Zhejiang University Hangzhou 310027 China

This paper proposes a new adaptive post-filtering algorithm to remove coding artifacts in block-based video coder. The proposed method concentrates on blocking and ringing artifacts removal. For de-blocking, the blocking strength is identified to determine the filtering range, and the maximum quantization parameter of the image is used to adapt the 1D fuzzy filter. For de-ringing, besides the edge detection, a complementary ringing detection method is proposed to locate the neglected ringing blocks, and the gradient threshold is adopted to adjust the parameter of 2D fuzzy filter. Experiments are performed on the MPEG-4 sequences. Compared with other methods, the proposed one achieves better detail preservation and artifacts removal performance with lower computational cost.

关键词： Adaptive fuzzy filter Blocking artifacts Ringing artifacts De-blocking De-ringing

Multi-attribute decision-making approach dealing with uncertain linguistic assessment information

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Journal of Southeast University(English Edition) 2008年第S1期24卷 7-10页

作者： gu, jing Zhou, Zongfang School of Management and Economics University of Electronic Science and Technology of China Chengdu 610054 China

An approach is presented to deal with a multi-attribute decision-making problem in which the attribute weights are unknown and the attribute values take the form of uncertain linguistic variables. First, a linguistic assessment standard is set up to deal with the uncertain linguistic attributes, and the operation laws of uncertain linguistic variables and the uncertain linguistic weighting average(ULWA)operator are introduced. Then a ranking formula of uncertain linguistic variables based on expectation-variance is proposed. As for the case without weight information, a goal program based on a warp function is constructed to determine the attribute weights, and the ULWA operator is utilized to aggregate the assessment information of uncertain linguistic variables, and the corresponding alternatives are ranked by a formula based on expectation-variance. Finally, a numerical example is given, and the results demonstrate that it is much easier and faster for the ranking method based on expectation-variance when compared to the existing methods.

关键词： multi-attribute decision-making uncertain linguistic variables linguistic assessment standard expectation-variance

Exploration of Gas-Dependent Self-Adaptive Reconstruction Behavior of Cu₂O for Electrochemical CO₂ Conversion to Multi-Carbon Products

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NANO-MICRO LETTERS 2025年第1期17卷 1-17页

作者： Zhang, Chaoran gu, Yichuan Jiang, Qu Sheng, Ziyang Feng, Ruohan Wang, Sihong Zhang, Haoyue Xu, Qianqing Yuan, Zijian Song, Fang Shanghai Jiao Tong Univ Sch Mat Sci & Engn State Key Lab Met Matrix Composites Shanghai 200240 Peoples R China

Structural reconstruction of electrocatalysts plays a pivotal role in catalytic performances for CO2 reduction reaction (CO2RR), whereas the behavior is by far superficially understood. Here, we report that CO2 accessibility results in a universal self-adaptive structural reconstruction from Cu2O to Cu@CuxO composites, ending with feeding gas-dependent microstructures and catalytic performances. The CO2-rich atmosphere favors reconstruction for CO2RR, whereas the CO2-deficient one prefers that for hydrogen evolution reaction. With the assistance of spectroscopic analysis and theoretical calculations, we uncover a CO2-induced passivation behavior by identifying a reduction-resistant but catalytic active Cu(I)-rich amorphous layer stabilized by *CO intermediates. Additionally, we find extra CO production is indispensable for the robust production of C2H4. An inverse correlation between durability and FECO/FEC2H4 is disclosed, suggesting that the self-stabilization process involving the absorption of *CO intermediates on Cu(I) sites is essential for durable electrolysis. guided by this insight, we design hollow Cu2O nanospheres for durable and selective CO2RR electrolysis in producing C2H4. Our work recognizes the previously overlooked passivation reconstruction and self-stabilizing behavior and highlights the critical role of the local atmosphere in modulating reconstruction and catalytic processes.

关键词： CO2 reduction reaction Electrocatalysts Cu2O Reconstruction Self-adaptive electrocatalysis

Six-long non-coding RNA signature predicts recurrence-free survival in hepatocellular carcinoma

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World Journal of Gastroenterology 2019年第2期25卷 220-232页

作者： jing-Xian gu Xing Zhang Run-Chen Miao Xiao-Hong Xiang Yu-Nong Fu jing-Yao Zhang Chang Liu kai Qu Department of Hepatobiliary Surgery The First Affiliated Hospital of Xi’an Jiaotong University

BACKGROUND Recent evidence shows that long non-coding RNAs(lncRNAs) are closely related to hepatogenesis and a few aggressive features of hepatocellular carcinoma(HCC). Increasing studies demonstrate that lncRNAs are potential prognostic factors for HCC. Moreover, several studies reported the combination of lncRNAs for predicting the overall survival(OS) of HCC, but the results varied. Thus,more effort including more accurate statistical approaches is needed for exploring the prognostic value of lncRNAs in *** To develop a robust lncRNA signature associated with HCC recurrence to improve prognosis prediction of *** Univariate COX regression analysis was performed to screen the lncRNAs significantly associated with recurrence-free survival(RFS) of HCC in GSE76427 for the least absolute shrinkage and selection operator(LASSO) modelling. The established lncRNA signature was validated and developed in The Cancer Genome Atlas(TCGA) series using Kaplan-Meier curves. The expression values of the identified lncRNAs were compared between the tumor and non-tumor tissues. Pathway enrichment of these lncRNAs was conducted based on the significantly co-expressed genes. A prognostic nomogram combining the lncRNA signature and clinical characteristics was *** The lncRNA signature consisted of six lncRNAs: MSC-AS1, POLR2 J4, EIF3 J-AS1,SERHL, RMST, and PVT1. This risk model was significantly associated with the RFS of HCC in the TCGA cohort with a hazard ratio(HR) being 1.807(95%CI[confidence interval]: 1.329-2.457) and log-rank P-value being less than 0.001. The best candidates of the six-lncRNA signature were younger male patients with HBV infection in relatively early tumor-stage and better physical condition but with higher preoperative alpha-fetoprotein. All the lncRNAs were significantly upregulated in tumor samples compared to non-tumor samples(P < 0.05). The most significantly enriched pathways of the lncRNAs were TGF-β signaling pathway, cellula

关键词： Long non-coding RNAs Hepatocellular carcinoma Prognostic signature Recurrence-free survival Least absolute shrinkage and selection operator

Comparative Analysis of Microwave Brightness Temperature Data in Northeast China Using AMSR-E and MWRI Products

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Chinese Geographical Science 2011年第1期21卷 84-93页

作者： gu Lingjia ZHAO kai ZHANG Shuwen ZHANG Shuang Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun 130012 China College of Electronic Science & Engineering Jilin University Changchun 130012 China

With such significant advantages as all-day observation, penetrability and all-weather coverage, passive mi-crowave remote sensing technique has been widely applied in the research of global environmental change. As the sat-ellite-based passive microwave remote sensor, the Advanced Microwave Scanning Radiometer-Earth Observing Sys-tem (AMSR-E) loaded on NASA's (National Aeronautics and Space Administration of USA) Aqua satellite has been popularly used in the field of microwave observation. The Microwave Radiation Imager (MWRI) loaded on the Chi-nese FengYun-3A (FY-3A) satellite is an AMSR-E-like conical scanning microwave sensor, but there are few reports about MWRI data. This paper firstly proposed an optimal spatial position matching algorithm from rough to exact for the position matching between AMSR-E and MWRI data, then taking Northeast China as an example, comparatively analyzed the microwave brightness temperature data derived from AMSR-E and MWRI. The results show that when the antenna footprints of the two sensors are filled with either full water, or full land, or mixed land and water with ap-proximate proportion, the errors of brightness temperature between AMSR-E and MWRI are usually in the range from -10 K to +10 K. In general, the residual values of brightness temperature between the two microwave sensors with the same spatial resolution are in the range of ±3 K. Because the spatial resolution of AMSR-E is three times as high as that of MWRI, the results indicate that the quality of MWRI data is better. The research can provide useful information for the MWRI data application and microwave unmixing method in the future.

关键词： AMSR-E MWRI FY-3A satellite brightness temperature spatial resolution spatial position matching Northeast China