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State estimation for delayed switched positive systems: delayed radius approach

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Science China(Information Sciences) 2024年第8期67卷 190-205页

作者： Weizhong CHEN Zhongyang FEI Xudong ZHAO zheng-guang WU School of Electronics and Information Xi'an Polytechnic University Research Institute of Intelligent Control and Systems Harbin Institute of Technology Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education Dalian University of Technology School of Control Science and Engineering Dalian University of Technology State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang University

In this paper, an interval estimation scheme is developed for delayed switched positive systems（DSPS） with mode-dependent average dwell time switching. A lossless zonotopic estimation approach is proposed for the delayed intersection zonotope with the positive generator matrix. First, considering the existence of asynchronism between the system mode and the correction matrix mode, the mismatched intersection zonotope is constructed for DSPS to verify the consistency between the system model and ***, by utilizing the introduced radius definitions, the ?∞performance is addressed to optimize the size of delayed intersection zonotopes. Subsequently, we present a joint-design approach of switching signals and the mode-dependent correction matrix by constructing positive generator matrix-based delayed radius functions. Furthermore, guaranteed nonnegative state bounds are derived for the considered DSPS based on the proposed lossless zonotopic estimation criteria. Finally, detailed simulations are conducted to validate the feasibility and superiority of the developed methods.

关键词： delayed switched positive systems interval estimation asynchronous correction matrix zonotopes mode-dependent average dwell time

Non-uniform thermal behavior of single-layer spherical reticulated shell structures considering time-variant environmental factors: analysis and design

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第3期25卷 223-237页

作者： Wucheng XU Xiaoqing zheng Xuanhe ZHANG Zhejie lai Yanbin SHEN College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China Center for Balance Architecture Zhejiang UniversityHangzhou 310028China Innovation Center of Yangtze River Delta Zhejiang UniversityJiaxing 314100China Zhejiang Provincial Key Laboratory of Space Structures Zhejiang UniversityHangzhou 310058China

Contrary to conventional design methods that assume uniform and slow temperature changes tied to atmospheric conditions,single-layer spherical reticulated shells undergo significant non-uniform and time-variant temperature variations due to dynamic environmental *** differences can affect structural performance and pose safety ***,a systematic numerical method was developed and applied to simulate long-term temperature variations in such a structure under real environmental conditions,revealing its non-uniform distribution characteristics and time-variant regularity.A simplified design method for non-uniform thermal loads,accounting for time-variant environmental factors,was theoretically derived and validated through experiments and *** maximum deviation and mean error rate between calculated and tested results were 6.1℃ and 3.7%,*** temperature fields aligned with simulated ones,with deviations under 6.0℃.Using the design method,non-uniform thermal effects of the structure are *** member stress and nodal displacement under non-uniform thermal loads reached 119.3 MPa and 19.7 mm,representing increases of 167.5%and 169.9%,respectively,compared to uniform thermal *** impacts of healing construction time on non-uniform thermal effects were evaluated,resulting in construction *** methodologies and conclusions presented here can serve as valuable references for the thermal design,construction,and control of single-layer spherical reticulated shells or similar structures.

关键词： Non-uniform temperature field Non-uniform thermal load Non-uniform thermal effect Single-layer spherical reticulated shell Time-variant environmental factor

Mechanical property of cylindrical sandwich shell with gradient core of entangled wire mesh

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Defence Technology（防务技术） 2024年第1期31卷 510-522页

作者： Xin Xue Chao zheng Fu-qiang lai Xue-qian Wu Institute of Metal-rubber&Vibration Noise School of Mechanical Engineering and AutomationFuzhou UniversityFuzhou350116China Fujian Metallurgical Industry Design Institute Fuzhou350116China

To explore the wide-frequency damping and vibration-attenuation performances in the application of aerospace components,the cylindrical sandwich shell structure with a gradient core of entangled wire mesh was proposed in this ***,the gradient cores of entangled wire mesh in the axial and radial directions were prepared by using an in-house Numerical Control weaving machine,and the metallurgical connection between skin sheets and the gradient core was performed using vacuum ***,to investigate the mechanical properties of cylindrical sandwich shells with axial or radial gradient cores,quasi-static and dynamic mechanical experiments were carried *** primary evaluations of mechanical properties include secant stiffness,natural frequency,Specific Energy Absorption(SEA),vibration acceleration level,and so *** results suggest that the vibration-attenuation performance of the sandwich shell is remarkable when the high-density core layer is at the end of the shell or abuts the inner *** axial gradient material has almost no influence on the vibration frequencies of the shell,whereas the vibration frequencies increase dramatically when the high-density core layer approaches the ***,compared to the conventional sandwich shells,the proposed functional grading cylindrical sandwich shell exhibits more potential in mass reduction,stiffness designing,and energy dissipation.

关键词： Entangled wire mesh Gradient cylindrical sandwich shell Vacuum brazing Secant stiffness Damping

Current status and challenges of pig-to-human organ xenotransplantation

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Science China(Life Sciences) 2024年第4期67卷 829-831页

作者： Minghui Fang Yong-guang Yang zheng Hu Key Laboratory of Organ Regeneration&Transplantation of Ministry of Education and National-Local Joint Engineering Laboratory of Animal Models for Human DiseasesThe First Hospital of Jilin UniversityChangchun 130061China

Organ shortage is a global *** collected by the Global Observatory on Donation and Transplantation reveals that over 150,000 solid organ transplants are conducted globally each year,a 52%increase from 2010(http://***/... 详细信息

关键词： globally global shortage

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

DLF-YOLOF:an improved YOLOF-based surface defect detection for steel plate

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Journal of Iron and Steel Research International 2024年第2期31卷 442-451页

作者： guang-hu Liu Mao-xiang Chu Rong-fen Gong Ze-hao zheng School of Electronic and Information Engineering University of Science and Technology LiaoningAnshan114051LiaoningChina

Surface defects can affect the quality of steel *** methods based on computer vision are currently applied to surface defect detection of steel ***,their real-time performance and object detection of small defect are still *** improved object detection network based on You Only Look One-level Feature(YOLOF)is proposed to show excellent performance in surface defect detection of steel plate,called ***,the anchor-free detector is used to reduce the network ***,deformable convolution network and local spatial attention module are introduced into the feature extraction network to increase the contextual information in the feature ***,the soft non-maximum suppression is used to improve detection accuracy ***,data augmentation is performed for small defect objects during training to improve detection *** show the average precision and average precision for small objects are 42.7%and 33.5%at a detection speed of 62 frames per second on a single GPU,*** shows that DLF-YOLOF has excellent performance to meet the needs of industrial real-time detection.

关键词： Steel surface defects detection YOLOF Anchor-free detector Small object detection Real-time detection

An empirical model for high energy density lithium-(ion)batteries with ultra-thick electrodes

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Tungsten 2024年第1期6卷 230-237页

作者： Li-Ming Jin guang-guang Xing Nan Qin Yan-Yan Lu Jun-Sheng zheng Cun-Man Zhang Jim P.zheng School of Automotive Studies and Clean Energy Automotive Engineering Center Tongji UniversityShanghai 201804China Department of Electrical Engineering University at BuffaloThe State University of New YorkBuffaloNY 14260USA

Increasing the electrode thickness is a significant method to decrease the weight and volume ratio of the inactive components for high energy density of the *** this contribution,we extracted a repeating unit in the configurations and establish the empirical energy density model based on some *** this model,the effects of the electrode thickness on the energy density for lithium-ion batteries(LIBs),lithium metal batteries(LMBs),and anode-free lithium batteries(ALBs)are evaluated quantitively with the current parameters of the *** results demonstrate that the structure evolutions from LIBs,LMBs to ALBs with the reduction of the anode weight contribution,the energy density can be well improved *** the increase of the thickness of the electrode provide another route to furthe r enhance the energydensity by decreasing the weight contribution of inactive materials;meanwhile the effects for ALBs are higher than LMBs and LIBs due to the higher weight ratio of inactive *** empirical energy density model is also applied into the practical system and provide intuitional results to guide the battery design for higher energy density.

关键词： Empirical model High energy density Lithium batteries Ultra-thick electrodes

Biomineralization of soil with crude soybean urease using different calcium salts

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1788-1798页

作者： Yajie Weng Junjie zheng Hanjiang lai Mingjuan Cui Xingzhi Ding School of Civil and Hydraulic Engineering Huazhong University of Science and TechnologyWuhan430074China Zijin School of Geology and Mining Fuzhou UniversityFuzhou350108China College of Civil Engineering Fuzhou UniversityFuzhou350116China

Calcium salt is an important contributing factor for calcium-based *** study the effect of calcium salt on soil biomineralization using crude soybean urease,the calcium salts,including the calcium chloride (CaCl_(2)),calcium acetate ((CH_(3)COO)_(2)Ca) and calcium nitrate (Ca(NO_(3))_(2)),were used to prepare the biotreatment solution to carry out the biomineralization tests in this *** series of biomineralization tests in solution and sand column,respectively,were *** electron microscopy (SEM) and X-ray diffraction (XRD) were performed to determine the microscopic characteristics of the precipitated calcium carbonate (CaCO_(3)) *** experimental results indicate that the biomineralization effect is the best for the CaCl2 case,followed by (CH_(3)COO)_(2)Ca,and worst for Ca(NO_(3))_(2) under the test conditions of this study (i.e.1 mol/L of calcium salt-urea).The mechanism for the effect of the calcium salt on the biomineralization of crude soybean urease mainly involves: (1) inhibition of urease activity,and (2) influence on the crystal size and morphology of CaCO_(3).Besides Ca^(2+) ,the anions in solution can inhibit the activity of crude soybean urease,and NO_(3)− has a stronger inhibitory effect on the urease activity compared with both CH_(3)COO^(−) and Cl^(−) .The co-inhibition of Ca^(2+) and NO_(3)− on the activity of urease is the key reason for the worst biomineralization of the Ca(NO_(3))_(2) case in this *** difference in biomineralization between the CaCl_(2) and (CH_(3)COO)_(2) Ca cases is strongly correlated with the crystal morphology of the precipitated CaCO_(3).

关键词： Biomineralization Crude soybean urease Calcium salt Influence mechanism

Hydrogel loaded with bone marrow stromal cell-derived exosomes promotes bone regeneration by inhibiting inflammatory responses and angiogenesis

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World Journal of Stem Cells 2024年第5期16卷 499-511页

作者： Shuai Zhang Chuan Lu Sheng zheng guang Hong Division for International Collaborative and Innovative Dentistry Tohoku University Graduate School of DentistrySendai 980-8575MiyagiJapan School of Stomatology Zhejiang Chinese Medical UniversityHangzhou 310053Zhejiang ProvinceChina

BACKGROUND Bone healing is a complex process involving early inflammatory immune regu-lation,angiogenesis,osteogenic differentiation,and *** repair poses challenges for orthopedic surgeons,necessitating the search for efficient healing *** To investigate the underlying mechanism by which hydrogel-loaded exosomes derived from bone marrow mesenchymal stem cells(BMSCs)facilitate the process of fracture *** Hydrogels and loaded BMSC-derived exosome(BMSC-exo)gels were charac-terized to validate their *** vitro evaluations were conducted to assess the impact of hydrogels on various stages of the healing *** could recruit macrophages and inhibit inflammatory responses,enhance of human umbilical vein endothelial cell angiogenesis,and promote the osteogenic differen-tiation of primary cranial ***,the effect of hydrogel on fracture healing was confirmed using a mouse fracture *** The hydrogel effectively attenuated the inflammatory response during the initial repair stage and subsequently facilitated vascular migration,promoted the formation of large vessels,and enabled functional vascularization during bone *** effects were further validated in fracture *** We successfully fabricated a hydrogel loaded with BMSC-exo that modulates macrophage polarization and angiogenesis to influence bone regeneration.

关键词： Hydrogel Bone marrow mesenchymal stem cells Macrophage polarization Angiogenesis Bone regeneration