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Study on frictional behavior of SiC_(f)/SiC composite clad tube clamping condition under nuclear irradiation

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Friction 2024年第5期12卷 919-938页

作者： Chenglong XIAO Liangliang SHEN Tianqi ZHU Jianbo TANG Ximing XIE Xinyu FAN Jian XU Zhiying REN School of Mechanical Engineering Zhejiang University of TechnologyHangzhou310023China Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Material Technology and EngineeringChinese Academy of SciencesNingbo315201China State Key Laboratory of Fine Chemicals Liaoning High-Performance Polymer Engineering Research CenterSchool of Chemical EngineeringDalian University of TechnologyDalian116024China School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou350116China School of Computer science and Technology Shandong UniversityQingdao266237China Aviation Industry Corporation of China Ltd.Beijing100028China

Silicon carbide fiber reinforced silicon carbide matrix(SiC_(f)/SiC)composite is the key cladding material of nuclear fuel,which determines the safety and reliability of nuclear fuel storage and *** replacement of its storage and transportation scenario needs to be completed by the manipulator,but the application of SiC_(f)/SiC wear,fracture,and nuclear leakage in the snatching process of brittle-flexible-rigid contact in the irradiation environment has been seriously restricted due to unclear understanding of the damage ***,the effects of irradiation dose and clamping load on the friction characteristics of the contact interface between SiC_(f)/SiC clad tube are studied in this paper,and the effects of irradiation parameters and clamping force on the static friction coefficient of the contact interface between the clad tube and flexible nitrile are *** on the Greenwood-Williamson tribological model,a numerical model of the shape and structure of the contact micro-convex at the micro-scale of the clamping interface is constructed by introducing the multi-surface integral,and finally verified by *** research results show that there is a unique“Irradiation suppression zone”under the clamping condition of SiC_(f)/SiC cladding tube under the nuclear irradiation environment,and the growth of static friction coefficient slows down until stagnates after irradiation reaches a certain extent(600 kGy),and there will be a decline when the irradiation dose continues to increase,among which the clamping force of 15.2 N within the irradiation interval of 1,000 kGy can meet the safety of nuclear environment *** results of this paper can provide an important theoretical basis and application guidance for the safe operation of SiC_(f)/SiC cladding tubes in the storage and transportation clamping process.

关键词： SiC_(f)/SiC Clad tube nuclear irradiation conditions Greenwood-Williamson tribological model multi-surface integral

Stem cell-based ischemic stroke therapy:Novel modifications and clinical challenges

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Asian Journal of Pharmaceutical sciences 2024年第1期19卷 18-34页

作者： Yuankai Sun Xinchi Jiang Jianqing Gao Institute of Pharmaceutics College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China Hangzhou Institute of Innovative Medicine College of Pharmaceutical SciencesZhejiang UniversityHangzhou 310058China Dr.Li Dak Sum&Yip Yio Chin Center for Stem Cell and Regenerative Medicine Zhejiang UniversityHangzhou 310058China Department of Pharmacy The Second Affiliated HospitalZhejiang University School of MedicineHangzhou 310009China

Ischemic stroke(IS)causes severe disability and high mortality *** cell(SC)therapy exhibits unique therapeutic potential for IS that differs from current ***’s cell homing,differentiation and paracrine abilities give hope for *** studies on SC modification have enhanced therapeutic effects for IS,including gene transfection,nanoparticle modification,biomaterial modification and *** improve survival rate,homing,neural differentiation,and paracrine abilities in ischemic ***,many problems must be resolved before SC therapy can be clinically *** issues include production quality and quantity,stability during transportation and storage,as well as usage ***,we reviewed the brief pathogenesis of IS,the“multi-mechanism”advantages of SCs for treating IS,various SC modification methods,and SC therapy *** aim to uncover the potential and overcome the challenges of using SCs for treating IS and convey innovative ideas for modifying SCs.

关键词： Ischemic stroke Stem cell therapy Stem cell modification Cell therapy challenge

Asymmetrically coordinated main group atomic In-S_(1)N_(3)interface sites for promoting electrochemical CO_(2)reduction

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Nano Research 2024年第6期17卷 5011-5021页

作者： Yan Gao Jinlong Ge Jingqiao Zhang Ting Cao Zhiyi Sun Wensheng Yan Yu Wang Jie Lin Wenxing Chen Zheng Liu Anhui Provincial Engineering Laboratory of Silicon-based Materials Bengbu UniversityBengbu 233030China State Key Laboratory of Environmental Criteria and Risk Assessment Chinese Research Academy of Environmental SciencesBeijing 100012China SEPA Key Laboratory of Eco-Industry Chinese Research Academy of Environmental SciencesBeijing 100012China ningbo Institute of Materials Technology and Engineering Chinese Academy of ScienceNingbo 315201China Energy&Catalysis Center School of Materials Science and EngineeringBeijing Institute of TechnologyBeijing 100081China National Synchrotron Radiation Laboratory University of Science and Technology of ChinaHefei 230029China Shanghai Synchrotron Radiation Facilities Shanghai Institute of Applied PhysicsChinese Academy of ScienceShanghai 201204China

Designing catalysts with highly active,selectivity,and stability for electrocatalytic CO_(2)to formate is currently a severe ***,we developed an electronic structure engineering on carbon nano frameworks embedded with nitrogen and sulfur asymmetrically dual-coordinated indium active sites toward the efficient electrocatalytic CO_(2)reduction *** expected,atomically dispersed In-based catalysts with In-S_(1)N_(3)atomic interface with asymmetrically coordinated exhibited high efficiency for CO_(2)reduction reaction(CO_(2)RR)to *** achieved a maximum Faradaic efficiency(FE)of 94.3%towards formate generation at−0.8 V *** hydrogen electrode(RHE),outperforming that of catalysts with In-S2N2 and In-N4 atomic *** at a potential of−1.10 V ***,In-S_(1)N_(3)achieves an impressive Faradaic efficiency of 93.7%in flow *** catalytic performance of In-S_(1)N_(3)sites was confirmed to be enhanced through in-situ X-ray absorption near-edge structure(XANES)measurements under electrochemical *** discovery provides the guidance for performance regulation of main group metal catalysts toward CO_(2)RR at atomic scale.

关键词： indium single-site catalyst main group metal asymmetrical coordination CO_(2)reduction reaction structure-activity relationship

A Novel Disturbance Observer Based Fixed-Time Sliding Mode Control for Robotic Manipulators With Global Fast Convergence

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IEEE/CAA Journal of Automatica Sinica 2024年第3期11卷 661-672页

作者： Dan Zhang Jiabin Hu Jun Cheng Zheng-Guang Wu Huaicheng Yan IEEE Zhejiang University of Technology Guangxi Normal University Zhejiang University the East China University of science and Technology

This paper proposes a new global fixed-time sliding mode control strategy for the trajectory tracking control of uncertain robotic ***,a fixed-time disturbance observer(FTDO) is designed to deal with the adverse effects of model uncertainties and external disturbances in the manipulator *** an adaptive scheme is used and the adaptive FTDO(AFTDO) is developed,so that the priori knowledge of the lumped disturbance is not ***,a new non-singular fast terminal sliding mode(NFTSM) surface is designed by using an arctan function,which helps to overcome the singularity problem and enhance the robustness of the *** on the estimation of the lumped disturbance by the AFTDO,a fixed-time non-singular fast terminal sliding mode controller(FTNFTSMC)is developed to guarantee the trajectory tracking errors converge to zero within a fixed *** settling time is independent of the initial state of the *** addition,the stability of the AFTDO and FTNFTSMC is strictly proved by using Lyapunov ***,the fixed-time NFESM(FTNFTSM) algorithm is validated on a 2-link manipulator and comparisons with other existing sliding mode controllers(SMCs) are *** comparative results confirm that the FTNFTSMC has superior control performance.

关键词： Disturbance observer(DO) fixed-time non-singular sliding mode control robotic manipulator trajectory tracking

Effects of impregnation sequence on the NH_(3)-SCR activity and hydrothermal stability of a Ce-Nb/SnO_(2) catalyst

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Journal of Environmental sciences 2024年第4期138卷 450-457页

作者： Ying Zhu Wenpo Shan Zhihua Lian Jingjing Liu Yan Zhang Hong He Center for Excellence in Regional Atmospheric Environment and Key Laboratory of Urban Pollutant Conversion Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Zhejiang Key Laboratory of Urban Environmental Processes and Pollution Control Ningbo Urban Environment Observation and Research StationInstitute of Urban EnvironmentChinese Academy of SciencesNingbo 315800China State Key Joint Laboratory of Environment Simulation and Pollution Control Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of sciences Beijing 100049China

Hydrothermal stability is crucial for the practical application of deNO_(x)catalyst on diesel vehicles,for the selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).SnO_(2)-based materials possess superior hydrothermal stability,which is attractive for the development of NH_(3)-SCR *** this work,a series of Ce-Nb/SnO_(2)catalysts,with Ce and Nb loading on SnO_(2)support,were prepared by impregnation *** was found that,the NH_(3)-SCR activities and hydrothermal stabilities of the Ce-Nb/SnO_(2)catalysts significantly varied with the impregnation sequences,and the Ce-Nb(f)/SnO_(2) catalyst that firstly impregnated Nb and then impregnated Ce exhibited the best *** characterization results revealed that CeNb(f)/SnO_(2)possessed appropriate acidity and redox ***,the strong synergistic effect between Nb and Sn species stabilized the structure and maintained the dispersion of acid *** study may provide a new understanding for the effect of impregnation sequence on activity and hydrothermal stability and a new environmental-friendly NH_(3)-SCR catalyst with potential applications for NO_(x)removal from diesel and hydrogenfueled engines.

关键词： NO_(x)emission control NH_(3)-SCR Hydrothermal stability Ce-Nb/SnO_(2)catalyst Impregnation sequence

Synergistic asymmetric diarylation of tethered alkenes via C–H functionalization of simple(hetero)arenes

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science China Chemistry 2024年第8期67卷 2710-2718页

作者： Jian Yao Can Zhao Lili Shao Xiaohong Huo Xiaoming Wang Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs Frontiers Science Center for Transformative MoleculesSchool of Chemistry and Chemical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Organometallic Chemistry and Shanghai Hongkong Joint Laboratory in Chemical Synthesis Center for Excellence in Molecular SynthesisShanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Materials science Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024China

By virtue of the atom-and step-economy, utilization of simple arenes as a supplant of pre-prepared aryl metal species or aryl halides for the synthesis of arylated chiral molecules has attracted great attention from the synthetic community. While transition-metal-catalyzed enantioselective diarylation of tethered alkenes has been employed to prepare important chiral cyclic compounds, the direct use of simple arenes as aryl precursors is still underdeveloped, probably due to the difficulties in the effective control of the reactivity, site-selectivity and/or enantioselectivity. Herein we report an asymmetric Pd/Ag dual metal catalytic system for the non-directed, site-and enantioselective domino Heck/intermolecular C–H functionalization of *** studies showed that Pd and Ag act in cooperation in the catalysis and the chiral bisphosphine ligand plays a bifunctional role, i.e., assisting the silver species in the cleavage of the aryl C–H bond, while inducing the enantioselectivity on direct complexation with palladium. This method provides an efficient approach to the corresponding chiral oxindoles with good enantiomeric excesses from a broad scope of arenes, including fluoroarenes, heteroarenes and several complex products derived from medicines or natural products.

关键词： asymmetric Pd/Ag dual metal catalytic system simple arenes C–H functionalization bifunctional role chiral oxindoles

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Turnip mosaic virus pathogenesis and host resistance mechanisms in Brassica

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Horticultural Plant Journal 2024年第4期10卷 947-960页

作者： Guanwei Wu Xinxin Fang Tianqi Yu Jianping Chen Fei Yan State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products Institute of Plant VirologyNingbo UniversityNingboZhejiang 315211China Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province Institute of Plant VirologyNingbo UniversityNingboZhejiang 315211China

Turnip mosaic virus(TuMV)is a devastating potyvirus pathogen that infects a wide variety of both cultivated and wild Brassicaceae *** urgently need more information and understanding of TuMV pathogenesis and the host responses involved in disease development in cruciferous *** displays great versatility in viral pathogenesis,especially in its replication and intercellular ***,in the coevolutionary arms races between TuMV and its hosts,the virus has evolved to co-opt host factors to facilitate its infection and counter host defense *** review mainly focuses on recent advances in understanding the viral factors that contribute to the TuMV infection cycle and the host resistance mechanism in ***,we propose some future research directions on TuMV pathogenesis and control strategies to design durable TuMV-resistant Brassica crops.

关键词： Turnip mosaic virus Brassica Resistance genes Host factors Infection biology

Model Parameters Identification and Backstepping Control of Lower Limb Exoskeleton Based on Enhanced Whale Algorithm

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 100-114页

作者： Yan Shi Jiange Kou Zhenlei Chen Yixuan Wang Qing Guo School of Automation science and Electrical Engineering Beihang UniversityBeijing 100191China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China

Exoskeletons generally require accurate dynamic models to design the model-based controller conveniently under the human-robot interaction ***,due to unknown model parameters such as the mass,moment of inertia and mechanical size,the dynamic model of exoskeletons is difficult to ***,an enhanced whale optimization algorithm(EWOA)is proposed to identify the exoskeleton model ***,the periodic excitation trajectories are designed by finite Fourier series to input the desired position demand of exoskeletons with mechanical physical *** a backstepping controller based on the identified model is adopted to improve the human-robot wearable comfortable performance under cooperative ***,the proposed Model parameters identification and control are verified by a two-DOF exoskeletons *** knee joint motion achieves a steady-state response after 0.5 ***,the position error of hip joint response is less than 0.03 rad after 0.9 *** addition,the steady-state human-robot interaction torque of the two joints is constrained within 15 N·*** research proposes a whale optimization algorithm to optimize the excitation trajectory and identify model ***,an enhanced mutation strategy is adopted to avoid whale evolution’s unsatisfactory local optimal value.

关键词： Parameter identification Enhanced whale optimization algorithm(EWOA) Backstepping Human-robot interaction Lower limb exoskeleton

State of the art in movement around a remote point:a review of remote center of motion in robotics

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Frontiers of Mechanical Engineering 2024年第2期19卷 1-28页

作者： Wuxiang ZHANG Zhi WANG Ke MA Fei LIU Pengzhi CHENG Xilun DING School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China ningbo Institute of Technology Beihang UniversityNingbo 315832China Intelligent Aerospace Manufacturing Engineering Technology Co. Ltd.Beijing 100191China

The concept of remote center of motion(RCM)is pivotal in a myriad of robotic applications,encompa-ssing areas such as medical robotics,orientation devices,and exoskeletal *** efficacy of RCM technology is a determining factor in the success of these robotic *** paper offers an exhaustive review of RCM technologies,elaborating on their various methodologies and practical *** delves into the unique characteristics of RCM across different degrees of freedom(DOFs),aiming to distill their fundamental *** addition,this paper categorizes RCM approaches into two primary classifications:design based and control *** are further organized according to their respective DOFs,providing a concise summary of their core *** upon the understanding of RCM’s versatile capabilities,this paper then transitions to an in-depth exploration of its applications across diverse robotic *** this review,we critically analyze the existing research challenges and issues that are inherently present in both RCM methodologies and their *** discussion is intended to serve as a guiding framework for future research endeavors and practical deployments in related areas.

关键词： remote center of motion mechanism robotics medical robot orientation device exoskeleton