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Lead-free piezoceramic macro-fiber composite actuators toward active vibration control systems

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Journal of Materiomics 2024年第1期10卷 78-85页

作者： Binquan wang Geng Huangfu Jie wang Shujun Zhang Yiping guo State Key Laboratory of Metal Matrix Composites School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China Institute for Superconducting and Electronic Materials Australian Institute for Innovative MaterialsUniversity of WollongongWollongongNSW2500Australia

Macro-fiber composite actuators(MFCAs)suffer from strict restrictions on the utilization of lead-containing precursors due to growing environmental *** address this issue,a novel lead-free MFCA based on potassium sodium niobate piezoceramics has been developed using the dice&fill *** MFCA demonstrates large electric field-induced displacement(31.4μm over-500-1500 V at 0.5 Hz),excellent frequency stability,and a str.ng linear relationship between the induced displacement and the external voltage ***,unlike lead-based MFCA that requires superposition of a negative dc bias voltage to pursue higher output performance but risks depolarization,lead-free MFCA can achieve larger displacement by superimposing only a positive bias *** device exhibits excellent reliability,maintaining a stable output over 10^(5) electrical ***,a“back-to-back”coupled MFCA has been developed to regulate bidirectional displacement,making it suitable for various practical applications,including active vibration *** approach has resulted in a 90%vibration reduction and provides new insights into the design of MFCAs,further facilitating their application in active vibration control systems.

关键词： Lead-free piezoceramic actuator Macro-fiber composite Active vibration control

Adaptive patient-cooperative compliant control of lower limb rehabilitation robot

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Biomimetic Intelligence & robotics 2024年第2期4卷 42-49页

作者： Lingling Chen Jjiabao Huang Yanglong wang Shijie guo Mengge wang Xin guo School of Artificial Intelligence Hebei University of TechnologyTianjin 300400China Inteligent rehabilitation Device and Detection Technology Engineer.ng research Centre of the Ministry of Education Tianjin 300400China School of Mechanical Engineer.ng Hebei University of TechnologyTianjin 300400China School of Electrical Engineer.ng Hebei University of TechnologyTianjin 300400China

With the increase in the number of stroke patients,there is a growing demand for rehabilitation ***-assisted training is expected to play a crucial role in meeting this *** ensure the safety and comfort of patients dur.ng rehabilitation training,it is important to have a patient-cooperative compliant control system for rehabilitation *** order to enhance the motion compliance of patients dur.ng rehabilitation training,a hierarchical adaptive patient-cooperative compliant control strategy that includes patient-passive exercise and patient-cooperative exercise is proposed.A low-level adaptive backstepping position controller is selected to ensure accurate tracking of the desired *** the high-level,an adaptive admittance controller is employed to plan the desired trajectory based on the interaction force between the patient and the *** results of the patient-robot cooperation experiment on a rehabilitation robot show a significant improvement in tracking trajectory,with a decrease of 76.45%in the dimensionless squared jerk(DSJ)and a decrease of 15.38%in the normalized root mean square deviation(NrMSD)when using the adaptive admittance *** proposed adaptive patient-cooperative control strategy effectively enhances the compliance of robot movements,thereby ensur.ng the safety and comfort of patients dur.ng rehabilitation training.

关键词： Compliant control Lower limb rehabilitation robot(LLrr) Adaptive admittance controller Adaptive backstepping controller Human-robot interaction

Prescribed Performance Tracking Control of Time-Delay Nonlinear Systems With Output Constraints

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IEEE/CAA Journal of Automatica Sinica 2024年第7期11卷 1557-1565页

作者： Jin-Xi Zhang Kai-Di Xu Qing-guo wang IEEE the State Key Laboratory of Synthetical Automation for Process Industries Northeastern UniversityShenyang 110819China Institute of Artificial Intelligence and Future Networks Beijing Normal UniversityZhuhai 519087 Guangdong Key Laboratory of Artificial Intelligence and Multi-Modal Data Processing Beijing Normal University-Hong Kong Baptist University United International CollegeZhuhai 519087

The problem of prescribed performance tracking control for unknown time-delay nonlinear systems subject to output constraints is dealt with in this paper. In contrast with related works, only the most fundamental requirements, i.e., boundedness and the local Lipschitz condition, are assumed for the allowable time delays. Moreover, we focus on the case where the reference is unknown beforehand, which renders the standard prescribed performance control designs under output constraints infeasible. To conquer these challenges, a novel robust prescribed performance control approach is put forward in this ***, a reverse tuning function is skillfully constructed and automatically generates a performance envelop for the tracking error. In addition, a unified performance analysis framework based on proof by contradiction and the barrier function is established to reveal the inherent robustness of the control system against the time delays. It turns out that the system output tracks the reference with a preassigned settling time and good accuracy,without constraint violations. A comparative simulation on a two-stage chemical reactor is carried out to illustrate the above theoretical findings.

关键词： Nonlinear systems output constraints prescribed performance reference tracking time delays

Implementation of integrated nonlocal sensing for object shape and rotational speed

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 6-12页

作者： Zhenyu guo Yunlong wang Zehong Chang Jiawei wang Junliang Jia Pei Zhang Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic DevicesSchool of PhysicsXi’an Jiaotong UniversityXi’an 710049China

The expeditious acquisition of information pertaining to objects through the utilization of quantum technology has been a perennial issue of *** far,the efficient utilization of information from dynamic objects with limited resources remains a significant ***,we realize a nonlocal integrated sensing of the object's amplitude and phase information by combining digital spiral imaging with the correlated orbital angular momentum *** amplitude information is utilized for object identification,while the phase information enables us to determine the rotational *** demonstrate the nonlocal identification of a rotating object's shape,irrespective of its rotational symmetry,and introduce the concept of the correlated rotational Doppler effect,establishing a fundamental connection between this effect and the classical rotational Doppler effect,i.e.,that both rely on extracting crucial information from the spiral spectrum of *** present study highlights a promising pathway towards the realization of quantum remote sensing and imaging.

关键词： digital spiral imaging orbital angular momentum correlated rotational Doppler effect

Mechanical response of a tunnel subjected to strike-slip faulting processes,based on a multi-scale modeling method

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Frontiers of Structural and Civil Engineer.ng 2024年第8期18卷 1281-1295页

作者： guoguo LIU Ping GEng Tianqiang wang Xiangyu guo Jiaxiang wang Ti DIng Key Laboratory of Transportation Tunnel Engineer.ng Ministry of EducationChengdu 610031China College of Civil Engineer.ng Huaqiao UniversityXiamen 361021China China railway Design Corporation Tianjin 300308China

The stick-slip action of strike-slip faults poses a significant threat to the safety and stability of underground *** this study,the north-east area of the Longmenshan fault,Sichuan,provides the geological background;the rheological characteristics of the crustal lithosphere and the nonlinear interactions between plates are described by Burger’s viscoelastic constitutive model and the friction constitutive model,respectively.A large-scale global numerical model for plate squeezing analysis is established,and the seemingly periodic stick-slip action of faults at different crust depths is *** a second model at a smaller scale,a local finite element model(sub-model),the time history of displacement at a ground level location on the Longmenshan fault plane in a stick-slip action is considered as the displacement *** integration of these models,creating a multi-scale modeling method,is used to evaluate the crack propagation and mechanical response of a tunnel subjected to strike-slip *** determinations of the recurrence interval of stick-slip action and the cracking characteristics of the tunnel are in substantial agreement with the previous field investigation and experimental results,validating the multi-scale modeling *** can be concluded that,regardless of stratum stiffness,initial cracks first occur at the inverted arch of the tunnel in the footwall,on the squeezed side under strike-slip *** smaller the stratum stiffness is,the smaller the included angle between the crack expansion and longitudinal direction of the tunnel,and the more extensive the crack expansion *** the tunnel in a high stiffness stratum,both shear and bending failures occur on the lining under strike-slip faulting,while for that in the low stiffness stratum,only bending failure occurs on the lining.

关键词： stick-slip action plate squeezing analysis multi-scale modeling method lining cracking mechanical response

Double-confined nanoheterostructure Sb/Sb_(2)S_(3)@Ti_(3)C_(2)T_(x)@C toward ultra-stable Li-/Na-ion batteries

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rare Metals 2024年第5期43卷 2067-2079页

作者： Dan wang Qun Ma Huan He Zhi-Yuan wang run-guo Zheng Hong-Yu Sun Yan-guo Liu Chun-Li Liu School of Materials Science and Engineer.ng Northeastern UniversityShenyang110819China School of resources and Materials Northeastern University at QinhuangdaoQinhuangdao 066004China Key Laboratory of Dielectric and Electrolyte Functional Material Hebei Province Qinhuangdao 066004China Department of Physics and Oxide research Center Hankuk University of Foreign StudiesYongin 17035Korea

Antimony-based materials with high capacities and moderate potentials are promising anodes for lithium-/-sodium-ion ***,their tremendous volume expansion and inferior conductivity lead to poor structural stability and sluggish reaction ***,a doubleconfined nanoheterostructure Sb/Sb_(2)S_(3)@Ti_(3)C_(2)T_(x)@C has been fabricated through a solvothermal method followed by low-temperature heat *** dual protection of“MXene”and“carbon”can better accommodate the volume expansion of Sb/Sb_(2)S_(3).The str.ng covalent bond(Ti-S,Ti-O-Sb,C-O-Sb)can firmly integrate Sb-based material with Ti_(3)C_(2)T_(x)and carbon,which significantly improves the structure *** addition,the carbon layer can restrain the oxidation of MXenes,and the nano-Sb/Sb_(2)S_(3)can facilitate electron/ion transport and suppress the restacking of *** heterogeneous interface between Sb and Sb_(2)S_(3)can further promote interfacial charge *** MXene-Sb/Sb_(2)S_(3)@C-1 with the optimal Sb content shows high specific capacities,comparable rate properties and ultra-stable cycling performances(250 m Ah·g^(-1)after 2500 cycles at 1 A·g^(-1)for sodium-ion batteries).Ex situ X-ray diffractometer(XrD)test reveals the storage mechanism including the conversion and alloying process of MXene-Sb/Sb_(2)S_(3)@*** voltammetry(CV)test results demonstrate that the pseudocapacitance behavior is dominant in MXene-Sb/Sb_(2)S_(3)@C-1,especially at large *** design paves the way for explor.ng high-performance alloy-based/conversion-type anode for energy storage devices.

关键词： Sb/Sb_(2)S_(3) MXene Carbon Anode Lithium-ion batteries Sodium-ion batteries

robust video question answer.ng via contrastive cross-modality representation learning

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Science China(Information Sciences) 2024年第10期67卷 211-226页

作者： Xun YAng Jianming ZEng Dan guo Shanshan wang Jianfeng DOng Meng wang School of Information Science and Technology University of Science and Technology of China Institute of Artificial Intelligence Hefei Comprehensive National Science Center School of Computer Science and Information Engineer.ng Hefei University of Technology Institutes of Physical Science and Information Technology Anhui University School of Computer Science and Technology Zhejiang Gongshang University

Video question answer.ng(VideoQA) is a challenging yet important task that requires a joint understanding of low-level video content and high-level textual semantics. Despite the promising progress of existing efforts, recent studies revealed that current VideoQA models mostly tend to over-rely on the superficial correlations rooted in the dataset bias while overlooking the key video content, thus leading to unreliable results. Effectively understanding and modeling the temporal and semantic characteristics of a given video for robust VideoQA is crucial but, to our knowledge, has not been well investigated. To fill the research gap, we propose a robust VideoQA framework that can effectively model the cross-modality fusion and enforce the model to focus on the temporal and global content of videos when making a QA decision instead of exploiting the shortcuts in datasets. Specifically, we design a self-supervised contrastive learning objective to contrast the positive and negative pairs of multimodal input, where the fused representation of the original multimodal input is enforced to be closer to that of the intervened input based on video perturbation. We expect the fused representation to focus more on the global context of videos rather than some static keyframes. Moreover, we introduce an effective temporal order regularization to enforce the inherent sequential structure of videos for video representation. We also design a Kullback-Leibler divergence-based perturbation invariance regularization of the predicted answer distribution to improve the robustness of the model against temporal content perturbation of videos. Our method is model-agnostic and can be easily compatible with various VideoQA backbones. Extensive experimental results and analyses on several public datasets show the advantage of our method over the state-of-the-art methods in terms of both accuracy and robustness.

关键词： video question answer.ng cross-modality fusion contrastive learning cross-media reasoning

Hypoxic tumor microenvironment:Destroyer of natural killer cell function

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Chinese Journal of Cancer research 2024年第2期36卷 138-150页

作者： Yongfei Zhang Feifei guo Yufeng wang Cancer Center the First Hospital of Jilin UniversityChangchun 130021China

In recent years, immunotherapy has made remarkable progress in treating certain tumors and hematological malignancies. However, the efficacy of natural killer(NK) cells, which are an important subset of innate lymphocytes used in anticancer immunotherapy, remains limited. Hypoxia, a critical characteristic of the tumor microenvironment(TME), is involved in tumor development and resistance to radiotherapy, chemotherapy, and immunotherapy. Moreover, hypoxia contributes to the impairment of NK cell function and may be a significant factor that limits their therapeutic effects. Targeted hypoxia therapy has emerged as a promising research area for enhancing the efficacy of NK cell therapy. Therefore, understanding how the hypoxic TME influences NK cell function is crucial for improving antitumor treatment outcomes.

关键词： Hypoxia immunotherapy NK cell tumor microenvironment

Preparation and Swelling Kinetic Analysis of Poly (HPMC-co-AA-co-AM) Super Absorbent resin

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Journal of Wuhan University of Technology(Materials Science) 2024年第3期39卷 790-799页

作者：马砺 wang Xin LIU Xixi WEI Gaoming guo Ying School of Safety Science and Engineer.ng Xi’an University of Science and TechnologyXi'an 710054China Key Laboratory of Coal Fire Disaster Prevention Xi’an University of Science and TechnologyXi'an 710054China School of Energy Engineer.ng Xi’an Uni-versity of Science and TechnologyXi'an 710054China Yanzhou Coal Mining Co. Ltd.Zoucheng 237500China

Super absorbent resin(SAr)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking ***,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction *** optimized conditions are obtained by the experiment repeating for several *** water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,***,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAr are *** is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.

关键词： super absorbent resin swelling kinetics water absorption graft copolymerization hydroxypropyl methyl cellulose