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Adaptive fault-tolerant control based on boundary estimation for space robot under joint actuator faults and uncertain parameters

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Defence Technology（防务技术） 2019年第6期15卷 964-971页

作者： rong-Hua Lei Li chen School of Mechanical Engineering and Automation Fuzhou University

Since the joint actuator of the space robot executes the control instructions frequently in the harsh space environment,it is prone to the partial loss of control effectiveness(PLCE)*** adaptive fault-tolerant control algorithm is designed for a space robot system with the uncertain parameters and the PLCE actuator *** mathematical model of the system is established based on the Lagrange method,and the PLCE actuator fault is described as an effectiveness *** lower bound of the effectiveness factors and the upper bound of the uncertain parameters are estimated by an adaptive strategy,and the estimated value is fed back to the control *** with the traditional fault-tolerant algorithms,the proposed algorithm does not need to predetermine the lower bound of the effectiveness factor,hence it is more in line with the actual engineering *** is proved that the algorithm can guarantee the stability of the closed-loop system based on the Lyapunov function *** numerical simulation results show that the proposed algorithm can not only compensate for the uncertain parameters,but also can tolerate the PLCE actuator faults effectively,which verifies the effectiveness and superiority of the control scheme.

关键词： Space robot Actuator faults Uncertain parameters Effectiveness factor Fault-tolerant control

Stereoselective synthesis of substituted 1,3-dienes from propargylic esters: electrophilic-metal or redox catalysis?

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Science China Chemistry 2024年第5期67卷 1384-1396页

作者： Mengfu dai Liangliang Song Liang-An chen Jiangsu Collaborative Innovation Center of Biomedical Functional Materials Jiangsu Key Laboratory of New Power BatteriesSchool of Chemistry and Materials ScienceNanjing Normal UniversityNanjing 210023China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of Chemical EngineeringNanjing Forestry UniversityNanjing 210037China

1,3-Diene architectures are not only widely present in natural products, pharmaceuticals, and functional organic materials but also serve as versatile building blocks to furnish important functionalized molecules in synthetic chemistry due to conjugated repeating C=C units. Accordingly, various strategies to access substituted 1,3-dienes in a stereoselective manner have been developed. However, chemo-, regio-and stereoselective synthesis of highly substituted 1,3-dienes still remains elusive and challenging. Readily available propargylic esters have emerged as an appealing class of synthetic intermediates for accessing functionalized 1,3-dienes, especially challenging tri-or tetrasubstituted variants, via transition-metal catalysis, including electrophilic metal and redox neutral catalysis. This review, for the first time, systematically highlights recent advances in transitionmetal catalyzed synthesis of substituted 1,3-dienes from propargylic esters, discusses the mechanisms and synthetic utilities, and gives the remaining challenges and potential opportunities in this field.

关键词： 1 3-diene propargylic ester Lewis acid redox catalysis transition metal

Recent progress in metal-organic frameworks(Part II—material application)

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Science China Chemistry 2025年

作者： Jiandong Pang Wentao Jiang Xue-Wen Zhang Hao-Long Zhou Yuxiu Sun Wei Gong Bin Wang Fuyin Ma Linwei He Long chen Qiang chen He-Qi Zheng Yuanjing Cui Wen-Jie Shi Chao Zhang Mei Wang Yue-Biao Zhang Jie-Peng Zhang Chongli Zhong Yong Cui Shuao Wang Jian-rong Li Guodong Qian Tong-Bu Lu Huan Pang Xian-He Bu Institute for New Energy Materials and Low Carbon Technologies School of Materials Science and Engineering Tianjin University of Technology School of Chemistry and Chemical Engineering Yangzhou University School of Materials Science and Engineering Nankai University School of Physical Science and Technology ShanghaiTech University MOE Key Laboratory of Bioinorganic and Synthetic Chemistry GBRCE for Functional Molecular Engineering School of Chemistry IGCMESun Yat-sen University Department of Chemistry Shantou University School of Chemical Engineering and Technology Tiangong University School of Chemistry and Chemical Engineering Shanghai Jiao Tong University State Key Laboratory of Radiation Medicine and Protection School for Radiological and Interdisciplinary Sciences Soochow University College of Materials Science & Engineering Beijing University of Technology State Key Laboratory of Silicon and Advanced Semiconductor Materials Cyrus Tang Center for Sensor Materials and ApplicationsSchool of Materials Science & Engineering Zhejiang University

As a class of functional crystalline porous materials, metal-organic frameworks(MOFs) gained rapid development in the past three decades and a large number of MOFs with ordered structures, high surface areas, and functionalized channels have been investigated. MOFs and MOF-derived/composite materials show great potential in many application fields. In this review, we discussed the main applications of MOFs and MOF-derived/composite materials in small molecule storage, separation, luminescence, sensing, multitype catalysis, and energy storage. In addition, challenges and problems in the future research of MOFsrelated fields are also discussed.

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Study on growing correlation length prior to the earthquakes occurred in Gansu Province and its nearby area

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Acta Seismologica Sinica(English Edition) 2004年第5期17卷 564-570页

作者： rong dai-lu(荣代潞) LI Ya-rong(李亚荣) LIU Xu-zhou(刘旭宙) Lanzhou Base of Center for analysis and Prediction China Earthquake AdministrationLanzhou730000China Lanzhou Base of Center for analysis and PredictionChina Earthquake AdministrationLanzhou730000China Lanzhou Base of Center for analysis and PredictionChina Earthquake AdministrationLanzhou730000China

The growing correlation length prior to the moderate-great earthquakes occurred in Gansu Province and its nearby area since 1986 has been studied using the method of single-link cluster analysis (SLC). According to different conditions in the source area, the circular spatial window centered in the epicenter and the parallelgrammic spatial window along the fault belt have been selected. The results show that the phenomena of growing correlation length have been observed before the earthquakes studied in the paper.

关键词： moderate-great earthquake correlation length single-link cluster analysis Gansu

An INS/GNSS integrated navigation in GNSS denied environment using recurrent neural network

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Defence Technology（防务技术） 2020年第2期16卷 334-340页

作者： Hai-fa dai Hong-wei Bian rong-ying Wang Heng Ma Navigation Engineering Lab Naval Engineering UniversityWuhanCO430033China

In view of the failure of GNSS signals,this paper proposes an INS/GNSS integrated navigation method based on the recurrent neural network(RNN).This proposed method utilizes the calculation principle of INS and the memory function of the RNN to estimate the errors of the INS,thereby obtaining a continuous,reliable and high-precision navigation *** performance of the proposed method is firstly demonstrated using an INS/GNSS simulation ***,an experimental test on boat is also conducted to validate the performance of the *** results show a promising application prospect for RNN in the field of positioning for INS/GNSS integrated navigation in the absence of GNSS signal,as it outperforms extreme learning machine(ELM)and EKF by approximately 30%and 60%,respectively.

关键词： Inertial navigation system(INS) Global navigation satellite system(GNSS) Integrated navigation Recurrent neural network(RNN)

Modeling the Spatial-temporal Characteristics of Mutual Funds’Herd Behavior

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Journal of Systems Science and Systems Engineering 2021年第6期30卷 748-778页

作者： rong Guan Hongjia chen Shan Lu School of Statistics and Mathematics Central University of Finance and EconomicsBeijing 100081China

Herd behavior in financial markets often leads to unjustified macroscopic ***,despite existing studies on modeling herd behavior,how it varies across individual agents and over time remains *** show that herd behavior in mutual fund companies can be understood from the functional networks representing interactions inferred from investment ***,in this paper,the spatial characteristics of herd behavior stand for the topology relationships of observations in *** analyze the collective dynamics of mutual fund investment from 2003 to 2019 in China using the language of network science and show that herding behavior accompanies this industry's development but dwindles after the 2015 Chinese market *** integrating community detection analysis,we found an increased degree of coherence in the collective herding behavior of the system,even though the localization of herding behavior decreases for clusters of mutual fund companies when the systemic risk builds *** analysis showed that herding behavior impacts the payoff of individual fund companies differently across *** spatial-temporal changes of herding behavior between mutual funds presented in this paper shed light on the debate of individual versus systemic risk and,thus,could interest regulators and investors.

关键词： Mutual funds herding behavior complex network community detection

Nondestructive Nonlinear Optical Microscopy Revealed the Blackening Mechanism of Ancient Chinese Jades

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Research 2024年第3期2023卷 391-399页

作者： Yaxin chen rong Wang Minbiao Ji State Key Laboratory of Surface Physics and Department of Physics Human Phenome InstituteAcademy for Engineering and TechnologyKey Laboratory of Micro and Nano Photonic Structures(Ministry of Education)Yiwu Research Institute of Fudan UniversityFudan UniversityShanghai 200433China Department of Cultural Heritage and Museology Fudan UniversityShanghaiChina

Jade is most valued in Chinese culture since ancient times. For unearthed jade artifacts, the alteration color resulting from weathering effects and human activities provides information for cultural heritage conservation, archaeology, and history. Currently, the noninvasive 3-dimensional characterization of jade artifacts with high chemical and spatial resolution remains challenging. In this work, we applied femtosecond pump–probe microscopy and second harmonic generation microscopy techniques to study the black alteration of an ancient jade artifact of the late Spring and Autumn period (546 to 476 BC). The direct cause of the “mercury alteration” phenomena was discovered to be the conversion of metacinnabar from buried cinnabar in the tomb. Furthermore, a 3-dimensional optical reconstruction of the black alteration was achieved, providing a high-resolution method for analyzing the blackening mechanism without the need of sample damage. Our approach opens up new opportunities to extract microscopic spatiochemical information for a broad range of alteration colors in jade artifacts.

关键词： pump Nonlinear buried

WAVES IN PRE-STRETCHED INCOMPRESSIBLE SOFT ELECTROACTIVE CYLINDERS:EXACT SOLUTION

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Acta Mechanica Solida Sinica 2012年第5期25卷 530-541页

作者： Weiqiu chen Huihui dai Soft Matter Research Center (SMRC) Zhejiang University Hangzhou 310027 China Department of Engineering Mechanics Zhejiang University Hangzhou 310027 China Department of Mathematics City University of Hong Kong Kowloon Hong Kong China

This paper studies wave propagation in a soft electroactive cylinder with an under- lying finite deformation in the presence of an electric biasing field. Based on a recently proposed nonlinear framework for electroelastieity and the associated linear incremental theory, the basic equations governing the axisymmetric wave motion in the cylinder, which is subjected to homo- geneous pre-stretches and pre-existing axial electric displacement, are presented when the elec- troactive material is isotropic and incompressible. Exact wave solution is then derived in terms of （modified） Bessel functions. For a prototype model of nonlinear electroactive material, illus- trative numerical results are given. It is shown that the effect of pre-stretch and electric biasing field could be significant on the wave propagation characteristics.

关键词： electroelastic waves finite pre-stretch soft electroactive cylinder dispersion rela-tion

A water-stable organolead iodide material for overall photocatalytic CO_(2) reduction

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Nano Research 2022年第12期15卷 10084-10089页

作者： rong chen Guodong Gao Jingshan Luo Institute of Photoelectronic Thin Film Devices and Technology Solar Energy Research CenterKey Laboratory of Photoelectronic Thin Film Devices and Technology of TianjinMinistry of Education Engineering Research Center of Thin Film Photoelectronic TechnologyRenewable Energy Conversion and Storage CenterNankai UniversityTianjin300350China

The utilization of perovskites as photocatalysts to convert CO_(2) into fuels and chemicals has received wide attention ***,their instability in water hinders their long-term application for overall photocatalytic CO_(2) ***,we integrate the water-stable perovskite-like organolead iodide crystalline material[Pb8I8(H2O)3]8+[-O2C(CH2)4CO_(2)-]4(TJU-16)with Au co-catalyst for photocatalytic CO_(2) reduction in aqueous solution without sacrificial *** the AM 1.5 G simulated illumination,the TJU-16 with 0.19 wt.‰ Au co-catalyst steadily generated electrons for CO_(2) reduction reaction,which was 2.2 times of pure *** Au0.19/TJU-16 catalyzed CO_(2) reduction at a rate of 84.2μmol·g-1·h-1,and achieved a solar-to-fuel(STF)conversion efficiency of 0.034%.Our work will motivate the rational design of water-stable perovskite-like materials for photocatalytic applications.

关键词： water-stable organolead iodide photocatalytic CO_(2)conversion