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Effect of Free-End Torsion on the Corrosion and mechanical Properties for Mg-3Zn-0.2Ca Alloy

Acta Metallurgica Sinica(English Letters) 2025年第1期38卷 59-70页

作者： Li-Lan Gao Jiang Ma Yan-Song Tan Xiao-Hao Sun Qi-Jun Gao De-Bao Liu Chun-Qiu Zhang Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin300384China School of Materials Science and Engineering Tianjin University of TechnologyTianjin300384China

Magnesium alloys with excellent degradability and biocompatibility are promising materials for biomedical implants,saving patients the burden of second ***,their mechanical properties and corrosion resistance are significantly below the requirements for implant *** study aims to improve the mechanical and corrosion resistance properties of Mg-3Zn-0.2Ca alloy by pre-torsion treatment,and find out the optimal shear *** rod-shaped Mg-3Zn-0.2Ca alloy specimens were pre-torsion treated at different torsion *** effect of free-end torsion on Mg-3Zn-0.2Ca alloy was characterized through microstructure analysis,mechanical testing,and corrosion ***-torsion treatment can refine grain and induce twins and dislocations in Mg-3Zn-0.2Ca *** surface hardness increases with the increase in torsion *** yield strength and ultimate strength initially increase and then decrease with increasing torsion angle,while ductility decreases with increasing torsion *** with a shear strain of 30%exhibit the highest tensile strength,reaching 284.78±10.62 MPa,with an elongation of 19.37±1.66%.Furthermore,they show a significant improvement in fatigue lives both before and after *** the stress amplitude is 120 MPa,the fatigue lives for specimens without pre-torsion treatment are 54,275 cycles and 4324 cycles before and after pre-corrosion,while they increased significantly to 92,015 cycles and 5050 cycles with the 30%shear strain,***,the 30%shear strain specimens show a significant reduction in corrosion *** conclusion,pre-torsion treatment can effectively modify the microstructure of Mg-3Zn-0.2Ca alloy,enhancing both mechanical properties and corrosion *** optimal shear strain for this improvement is 30%.This study provides a practical method to enhance the mechanical properties and corrosion resistance of Mg-3Zn-0.2Ca alloy,making it more suitable for biomedical implan

关键词： Magnesium alloy Pre-torsion Microstructure mechanical property Corrosion resistance

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Assessment of Multilevel Intransitive Noninterference by Nonblocking Analysis

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IEEE Transactions on Automatic control 2025年第5期70卷 2902-2917页

作者： Zhong, Wenjing Zhao, Jinjing Hu, Hesuan Xidian University School of Electro-Mechanical Engineering Xi'an710071 China National Key Laboratory of Science and Technology on Information System Security Beijing100101 China Nanyang Technological University School of Computer Science and Engineering College of Engineering 639798 Singapore Xi'an Jiaotong University State Key Laboratory for Manufacturing Systems Engineering Xi'an710054 China

Security of system behavior is a kind of information flow security, which is achieved by confusing the intruders via the indistinguishability of system behaviors. Noninterference is a typical notion to describe information flow security, for which multilevel intransitive noninterference (MINI) is an advanced variant. Since there is a lack of rigorous approach to assessing MINI, this article achieves so via observability theory. For systems modeled by labeled Petri nets (LPNs), two MINI properties, i.e., positive MINI (PMINI) and bipolar MINI (BMINI), are considered. First, a necessary and sufficient condition for their assessment is established via language equivalence. Language equivalence analyses for PMINI and BMINI are based on the existing trace equivalence and the proposed INI bisimulation, respectively. INI bisimulation is more comprehensive to describe negative noninterference than bisimulation. Second, another necessary and sufficient condition is established after the transformation of MINI assessment problem to nonblocking analysis problem. The core of such a problem transformation is the stepwise construction of nonblocking analyzer. This stepwise construction allows MINI assessment to proceed online before terminating at an appropriate time. In addition, this stepwise construction fully employs the concurrency of LPNs so that MINI can be assessed in a multithreaded way. Both online and multithreaded MINI assessments can improve assessment efficiency. © 1963-2012 IEEE.

关键词： Petri nets

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Real-time monitoring and analysis of hydraulic fracturing in surface well using microseismic technology:Case insights and methodological advances

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International Journal of Mining science and technology 2025年第4期35卷 619-638页

作者： Yanan Qian Ting Liu Cheng Zhai Hongda Wen Yuebing Zhang Menghao Zheng Hexiang Xu Dongyong Xing Xinke Gan State Key Laboratory of Coal Mine Disaster Prevention and Control China University of Mining and TechnologyXuzhou 221116China Yunlong Lake Laboratory of Deep Underground Science and Engineering Xuzhou 221003China Key Laboratory of Theory and Technology on Coal and Rock Dynamic Disaster Prevention and Control National Mine Safety AdministrationChina University of Mining and TechnologyXuzhou 221116China School of Safety Engineering China University of Mining and TechnologyXuzhou 221116China School of Emergency Management Chengdu UniversityChengdu 610106China School of Safety Science and Engineering Anhui University of Science and TechnologyHuainan 232001China Xinjiang Yaxin Coalbed Methane 156 Exploration Co. Ltd.Urumqi 841100China

Through a case analysis,this study examines the spatiotemporal evolution of microseismic(MS)events,energy characteristics,volumetric features,and fracture network development in surface well hydraulic fracturing.A total of 349 MS events were analyzed across different fracturing sections,revealing significant heterogeneity in fracture *** scanning results showed that cumulative energy values ranged from 240 to 1060 J across the sections,indicating notable *** reservoir volume(SRV)analysis demonstrated well-developed fracture networks in certain sections,with a total SRV exceeding 1540000 m^(3).The hydraulic fracture network analysis revealed that during the midfracturing stage,the density and spatial extent of MS events significantly increased,indicating rapid fracture propagation and the formation of complex *** the later stage,the number of secondary fractures near fracture edges decreased,and the fracture network *** comparing the branching index,fracture length,width,height,and SRV values across different fracturing sections,Sections No.1 and No.8 showed the best performance,with high MS event densities,extensive fracture networks,and significant energy ***,Sections No.4 and No.5 exhibited sparse MS activity and poor fracture connectivity,indicating suboptimal stimulation effectiveness.

关键词： Hydraulic fracturing Microseismic Source location Energy scanning Fracture network

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Underwater arbitrary ranging based on chirped pulse interferometry with a mode-locked laser

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Journal of Lightwave technology 2025年第11期43卷 5235-5243页

作者： Shi, Haonan Zhao, Haihan Xu, Xinyang Zhu, Zhiwei Zhai, Jingsheng Li, Xiaobo Tianjin University School of Marine Science and Technology Tianjin300072 China Research Institute of China Electronics Technology Group Corporation Science and Technology on Electro-Optical Information Security Control Laboratory No. 53 Tianjin300308 China The Chinese University of Hong Kong Department of Mechanical and Automation Engineering Hong Kong999077 Hong Kong Nanjing University of Aeronautics and Astronautics Key Laboratory of Space Photoelectric Detection and Perception Ministry of Industry and Information Technology Nanjing211106 China

Underwater distance measurement and length sensing, as fundamental functions of geoscience, are integrated into underwater robots and vessels in various forms of sensor payloads and play a crucial role in a wide range of remote sensing applications. Advanced laser-based detection systems and algorithms are essential for underwater tasks, such as detecting damage in underwater pipelines and conducting detailed structural health assessments. In this paper, we experimentally demonstrated an arbitrary underwater ranging system by the chirped pulse interferometry with a mode-locked laser. Water's inherent characteristic introduces dispersion, enabling unique distance discrimination. Adjusting the repetition frequency allows us to acquire the interference spectrum. A long fiber delay line, stabilized by the servo-controlled system, eliminates the ranging dead zone. The widest fringe of the interference spectrum, corresponding to an instantaneous repetition frequency, indicates the arbitrary measured distance. Leveraging a charge-coupled device detection module, we achieved an update rate of 13.5 Hz for the interference spectrum. Experimental results show a precise distance difference within 59.8 μm at the 5 m range underwater without the dead zone. © 2025 IEEE. All rights reserved.

关键词： Laser mode locking

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Minimum Initial Marking Estimation in Labeled Petri Nets Using Minimum Token Number Prediction

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IEEE Transactions on Automatic control 2025年第5期70卷 3296-3302页

作者： Yue, Hao Xu, Yakun Hu, Hesuan Wu, Weimin Li, Lingxi College of Computer Science and Technology Qingdao266580 China Xidian University School of Electro-Mechanical Engineering Xi'an710071 China Nanyang Technological University School of Computer Science and Engineering College of Engineering 639798 Singapore Zhejiang University State Key Laboratory of Industrial Control Technology Hangzhou310027 China Zhejiang University Institute of Cyber-Systems and Control Hangzhou310027 China Purdue University Elmore Family School of Electrical and Computer Engineering College of Engineering IndianapolisIN46202 United States

This article proposes an approach to addressing the problem of minimum initial marking (MuIM) estimation for labeled Petri nets (LPNs). We introduce the important concept of a label synthesis net for LPNs and develop a method for predicting the minimum number of tokens. By using this prediction method, we develop an algorithm that has polynomial complexity in the length of the observed label sequence for estimating MuIMs. An illustrative example is provided to show the effectiveness and efficiency of our proposed approach. Moreover, experimental results demonstrate its advantage over existing work. Finally, we provide a comparison of some representative studies in the literature for MuIM estimation. © 1963-2012 IEEE.

关键词： Discrete event simulation

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PLLA-PEG/mPEG Copolymer with Improved Hydrophilicity, Crystallinity, and Biocompatibility: An In-Depth Study on the Crystallization Kinetics

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ACS Applied Materials and Interfaces 2025年第20期17卷 30067-30080页

作者： Lian, Ruixian Zhou, Dong Xiao, Lan Rodrigues, João Sheng, Ruilong Bai, Zhishan Li, Yulin Liu, Changsheng The Key Laboratory for Ultrafine Materials of Ministry of Education Engineering Research Centre for Biomedical Materials of Ministry of Education Frontiers Science Center for Materiobiology and Dynamic Chemistry School of Materials Science and Engineering East China University of Science and Technology Shanghai200237 China Wenzhou Key Laboratory of Tissue Regeneration Medical Materials Wenzhou Institute of Shanghai University Wenzhou325000 China State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process School of Mechanical and Power Engineering East China University of Science and Technology Shanghai200237 China School of Medicine and Dentistry Griffith University QLD4222 Australia CQM-Centro de Química da Madeira MMRG Universidade da Madeira Campus da Penteada Madeira Funchal9000-390 Portugal

Poly(lactic acid) (PLA) possesses excellent biocompatibility and biodegradability for the construction of biomaterials. However, its limited crystallinity largely restricts practical application. In this study, four poly(l-lactic acid) (PLLA) copolymers were synthesized by incorporating two different molecular weights of PEG/mPEG (1K and 2K) chains with l-lactide via ring-opening polymerization (ROP). The impact of PEG/mPEG chains on the hydrophilicity and mechanical properties of the resulting copolymers, their crystallization kinetics, and activation energy was also examined. The results demonstrate that introducing PEG/mPEG chains could significantly improve the hydrophilicity, crystallinity, and crystallization rate and reduce the maximum crystallization temperature of the copolymer materials. Among the PLLA copolymers, PLLA-mPEG (2K) exhibits the most remarkable improvements in polymer crystallinity, crystallization rate, and reduction of the maximum crystallization temperature. The advancements in copolymer material properties were anticipated to significantly expand the potential applications for PLLA-based polymer materials, which also greatly improved the applicability as sustainable and controllable biopolymer materials. © 2025 American Chemical Society.

关键词： Biocompatibility

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Interference Suppression and Jitter Elimination Ability-Based Adaption Tracking Guidance for Robotic Fishes

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IEEE/CAA Journal of Automatica Sinica 2025年第1期12卷 126-137页

作者： Dongfang Li Jie Huang Rob Law Xin Xu Limin Zhu Edmond Q.Wu IEEE the School of Electrical Engineering and Automation Fuzhou University the Key Laboratory of System Control and Information Processing Ministry of Education the School of Electrical Engineering and Automation Fuzhou University 5G+Industrial Internet Institute Fuzhou University the University of Macau the College of Mechatronics and Automation National University of Defense Technology the School of Mechanical Engineering Shanghai Jiao Tong University the Department of Computer Science and Engineering Shanghai Jiao Tong University

This work presents an adaptive tracking guidance method for robotic fishes. The scheme enables robots to suppress external interference and eliminate motion jitter. An adaptive integral surge line-of-sight guidance rule is designed to eliminate dynamics interference and sideslip issues. Limited-time yaw and surge speed observers are reported to fit disturbance variables in the model. The approximation values can compensate for the system's control input and improve the robots' tracking ***, this work develops a terminal sliding mode controller and third-order differential processor to determine the rotational torque and reduce the robots' run jitter. Then, Lyapunov's theory proves the uniform ultimate boundedness of the proposed method. Simulation and physical experiments confirm that the technology improves the tracking error convergence speed and stability of robotic fishes.

关键词： Adaptive integral surge line-of-sight approximation robotic fish speed observer

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P-tuned FeN_(2)binuclear sites for boosted CO_(2)electro-reduction

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Journal of Energy Chemistry 2025年第2期101卷 816-824,I0018页

作者： Cao Guo Sanshuang Gao Jun Li Menglin Zhou Abdukader Abdukayum Qingquan Kong Yingtang Zhou Guangzhi Hu School of Materials and Energy Institute for Ecological Research and Pollution Control of Plateau LakesSchool of Ecology and Environmental ScienceYunnan UniversityKunming 650504YunnanChina Xinjiang Key Laboratory of Novel Functional Materials Chemistry College of Chemistry and Environmental SciencesKashi UniversityKashi 844000XinjiangChina School of Mechanical Engineering Chengdu UniversityChengdu 610106SichuanChina National Engineering Research Center for Marine Aquaculture Marine Science and Technology CollegeZhejiang Ocean UniversityZhoushan 316004ZhejiangChina

The recycling of CO_(2)through electrochemical processes offers a promising solution for alleviating the greenhouse effect;however,the activation of CO_(2)and desorption of^(*)CO in electrocatalytic CO_(2)reduction(ECR)frequently encounter high energy barriers and competitive hydrogen evolution reactions(HERs),which are urgent problems that need to be *** this study,a catalyst(P100-Fe-N/C)with homogeneous P-tuned FeN_(2)binuclear sites(N_(2)PFe-FePN_(2))was successfully synthesised,demonstrating satisfactory performance in the ECR to CO.P100-Fe-N/C attains a peak FECOof 98.01%and a normalized TOF of 664.7 h-1at-0.7 VRHE,surpassing the performance of the Fe binuclear catalyst without P and singleatoms *** the MEA cell,a FECOexceeding 90%can still be *** functional theory analysis indicates that the asymmetric coordination configuration induced by the incorporation of P facilitates a reduction in the system's *** modulation of P results in the d-band centre of the catalyst being positioned closer to the Fermi level,which facilitates the interaction of the catalyst with CO_(2),allowing more electrons to be injected into the CO_(2)molecule at the Fe binuclear sites and inhibiting the *** P-tuned FeN_(2)binuclear sites effectively lower the^(*)CO desorption barrier.

关键词： electrocatalysis Diatomic catalyst Heteroatom doping CO_(2)reduction reaction DFT calculation

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Adaptive terminal super-twisting prescribed performance controller for near-space vehicle based on data-driven model

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ISA Transactions 2025年 160卷 1-18页

作者： Zhang, Tianchen Ding, Yibo Yue, Xiaokui Li, Naying School of Astronautics Northwestern Polytechnical University Xi'an710072 China Research & Development Institute of Northwestern Polytechnical University in Shenzhen Sanhang Science &Technology Buliding No. 45th Gaoxin South 9th Road Nanshan District Shenzhen518063 China National Key Laboratory of Aerospace Flight Dynamics Northwestern Polytechnical University Xi'an710072 China Beijing Electro-mechanical Engineering Institute Beijing100074 China

A data-driven adaptive terminal super-twisting prescribed performance controller (DASTPC) is designed for near-space vehicle (NSV) to satisfy transient and steady-state performance, and prevent scramjet choking. Firstly, a novel predetermined-time performance function is proposed to guarantee that tracking error can converge to a prescribed bound of small residual sets at the predetermined time. Compared with traditional performance functions, the predetermined-time performance function can achieve faster respond speed, realize more accurate convergence, and avoid overlarge initial value of actuators. Secondly, by combining the predetermined-time performance function with sliding mode control, a novel non-singular fast terminal sliding surface and an improved adaptive super-twisting reaching law are proposed to improve computational efficiency and accelerate convergent rate of system. The adaptive reaching law can avoid excessive gains and attenuate chattering by automatically tuning control gain. Thirdly, a deep recurrent neural network-based long-short term memory (LSTM) is employed to learn time-series historical flight dynamics data offline, so as to construct a data-driven LSTM training model. This data-driven model replaces nominal dynamics model of NSV in DASTPC, effectively suppressing model uncertainties. In addition, a homogeneous high-order sliding mode observer is utilized to compensate for external disturbances, avoiding excessive parameter estimation. Since boundary conditions of the predetermined-time performance function are fully satisfied, the DASTPC can effectively restrict amplitude of angle of attack, thus ensuring the intake condition of scramjet. Ultimately, to illustrate the superiority of DASTPC, several sets of simulations are performed on NSV subject to prescribed performance bound, external disturbances and parameter perturbations. © 2025 ISA

关键词： Long short-term memory

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NO2 Emissions at Highway Toll Stations: Integrated Satellite and Traffic Data Insights from Holiday Analysis

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Water, Air, and Soil Pollution 2025年第7期236卷 1-17页

作者： Yang, Xinxiang Xu, Shenghao Zhang, Shuyu Tao, Yuanming Sher, Farooq Wong, Keng Yinn Wang, Bohong National & Local Joint Engineering Research Center of Harbour Oil & Gas Storage and Transportation Technology/Zhejiang Key Laboratory of Petrochemical Environmental Pollution Control Zhejiang Ocean University No.1 Haida South Road Zhoushan316022 China School of Environmental Science and Engineering Southern University of Science and Technology 1088 Xueyuan Avenue Shenzhen518055 China Department of Engineering School of Science and Technology Nottingham Trent University NottinghamNG11 8 NS United Kingdom Faculty of Mechanical Engineering Universiti Teknologi Malaysia Johor Skudai81310 Malaysia

Nitrogen dioxide (NO2), a significant urban pollutant, is a primary component of vehicular emissions that impacts air quality around highway infrastructure. Effective monitoring of NO2 near toll stations is essential for advancing sustainable transportation and air quality management. This study leverages data from the TROPOMI instrument aboard the Sentinel-5P satellite to observe NO2 distribution at five highway toll stations in Zhejiang Province, China, from January 2019 to June 2023, focusing on the effects of traffic volume changes during statutory holidays. key findings include: (1) During toll-free holidays, traffic volume surges by 49% while NO₂ concentrations at toll stations decrease by up to 21%. This suggests that reduced vehicle wait times help mitigate emissions, particularly when toll gates are open to allow smoother traffic flow. (2) In economically developed cities, prolonged vehicle queuing and idling increased NO2 emissions at toll stations by approximately 15–28%, emphasizing the need for effective congestion management to control emissions. (3) During the COVID-19 pandemic, preventive measures such as disinfection and health checks extend waiting times at toll stations, causing NO2 levels to rise by up to 35% even with an overall decrease in traffic volume. By integrating satellite data with traffic flow information, this study highlights the potential of optimized toll station infrastructure to reduce NO2 emissions and improve urban air quality, especially during peak traffic. These insights provide actionable recommendations for sustainable highway infrastructure management and air quality improvement. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.

关键词： Highway administration

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