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Resilient sliding mode control for 2D CPSs under denial-of-service attacks

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Science China(Information Sciences) 2024年第6期67卷 262-278页

作者： Lingling LI Rongni YANG Zhiguang FENG Ligang WU College of Intelligent Systems Science and engineering Harbin Engineering University School of Control Science and engineering Shandong University School of Astronautics Harbin Institute of Technology

This study addresses the resilient sliding mode control(SMC) problem for two-dimensional cyber-physical systems(2D CPSs) characterized by the Roesser model under denial-of-service attack(DoSA), which can interfere with signal transmission over the communication network. First, the DoS-A model is established by introducing constraints on the Do S frequency and duration. Then, based on active or silent attack situations, the considered system is described as a switched mode. Furthermore, together with Lyapunov theory, the average dwell time technique is employed to deduce sufficient criteria that assure the existence of the desired sliding mode controller. Finally, verification examples are provided to show the validity of the established SMC scheme.

关键词： two-dimensional systems cyber-physical systems denial-of-service attack resilient sliding mode control

Local environment regulation of transition metal dichalcogenide-based single-atom catalysts

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Rare Metals 2024年第9期43卷 4019-4037页

作者： Ming-Hui Li Jing Li Xiao-Yu Zheng Yao Zhou Advanced Research institute of Multidisciplinary Science andSchool of Chemistry and Chemical engineering Beijing Institute of Technology Laser Micro/Nano Fabrication Laboratory School of Mechanical Engineering Beijing Institute of Technology

Single-atom catalysts have risen significant attention in the realm of green electrocatalytic energy conversion to address energy and environmental sustainability challenges. Transition metal dichalcogenide（TMD）-based single-atom catalysts are considered highly effective in electrocatalysis due to the TMDs' notable specific surface area, tunable elemental species and efficient utilization of single atoms. In order to enhance electrocatalytic performance, it is imperative to elaborately engineer the local environment surrounding the active sites of single atoms within TMDs. In this review, we initially explore the effects of synthesis methods on single-atom active sites and the influence of loading of single atoms on catalytic performance for TMDs. The modulation strategies of the local environment surrounding single-atom sites in TMDs are elaborated, including substitution engineering,surface adsorption, vacancies, spatial confinement and dual-atom site strategies. For each modulation strategy, the effects of diverse local environments on various electrocatalytic applications are presented, such as the oxygen evolution reaction, oxygen reduction reaction, nitrogen reduction reaction, CO2reduction reaction and CO oxidation. Ultimately, this study presents a comprehensive overview of the challenges encountered and the potential directions for the advancement of single-atom catalysts based on TMDs in the realm of electrocatalysis.

关键词： Electrocatalysis

Investigations of the mechanical response of dummy HTPB propellant grain under ultrahigh acceleration overload conditions using onboard flight-test measurements

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Defence Technology（防务技术） 2024年第2期32卷 473-484页

作者： Yiming Zhang Ningfei Wang Weihua Ma Ran Wang Long Bai Yi Wu School of Aerospace engineering Beijing Institute of TechnologyBeijing 100081China Beijing System Design institute of Electro-mechanic engineering Beijing 100854China Xi'an Changfeng Research institute of Mechanism and Electricity Xi'an 710065China

In this paper,to study the mechanical responses of a solid propellant subjected to ultrahigh acceleration overload during the gun-launch process,specifically designed projectile flight tests with an onboard measurement system were *** projectiles containing dummy HTPB propellant grains were successfully recovered after the flight tests with an ultrahigh acceleration overload value of 8100 *** onboard-measured time-resolved axial displacement,contact stress and overload values were successfully obtained and *** compression tests of the dummy HTPB propellant used in the gunlaunched tests were carried out at low and intermediate strain rates to characterize the propellant's dynamic properties.A linear viscoelastic constitutive model was employed and applied in finite-element simulations of the projectile-launching *** the launch process,the dummy propellant grain exhibited large deformation due to the high acceleration overload,possibly leading to friction between the motor case and propellant *** calculated contact stress showed good agreement with the experimental results,though discrepancies in the overall displacement of the dummy propellant grain were *** dynamic mechanical response process of the dummy propellant grain was analysed in *** results can be used to estimate the structural integrity of the analysed dummy propellant grain during the gun-launch process.

关键词： Gun-launched flight test Dummy HTPB propellant Onboard measurements Utrahigh overload Mechanical response

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Mechanical responses and crystal plasticity model of CoCrNi medium-entropy alloy under ramp wave compression

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Matter and Radiation at Extremes 2024年第5期9卷 93-108页

作者： Jinlei Dong Xuping Zhang Guiji Wang Xianqian Wu Binqiang Luo Xuemiao Chen Fuli Tan Jianheng Zhao Chengwei Sun institute of Fluid Physics China Academy of Engineering PhysicsMianyang 621999China institute of Mechanics Chinese Academy of SciencesBeijing 100190China institute of Applied Electronics China Academy of Engineering PhysicsMianyang 621999China

It is of substantial scientific significance and practical value to reveal and understand the multiscale mechanical properties and intrinsic mechanisms of medium-entropy alloys(MEAs)under high strain rates and *** this study,the mechanical responses and deformation mechanisms of an equiatomic CoCrNi MEA are investigated utilizing magnetically driven ramp wave compression(RWC)with a strain rate of 105 s^(−1).The CoCrNi MEA demonstrates excellent dynamic mechanical responses and yield strength under RWC compared with other advanced *** characterizations reveal that grain refinement and abundant micromechanisms,including dislocation slip,stacking faults,nanotwin network,and Lomer–Cottrell locks,collectively contribute to its excellent performance during ***,dense deformation twins and shear bands intersect,forming a weave-like microstructure that can disperse deformation and enhance *** the basis of these observations,we develop a modified crystal plasticity model with coupled dislocation and twinning mechanisms,providing a relatively accurate quantitative description of the multiscale behavior under *** results of simulations indicate that the activation of multilevel microstructures in CoCrNi MEA is primarily attributable to stress inhomogeneities and localized strain during *** research offers valuable insights into the dynamic mechanical responses of CoCrNi MEA,positioning it as a promising material for use under extreme dynamic conditions.

关键词： deformation alloy microstructure

Multifunctional applications of gadolinium-doped cerium oxide(Ce1-xGdxO2-?) ceramics:A review

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Journal of Rare Earths 2024年第10期42卷 1817-1834页

作者： Subhadip Das Rakesh Bhaskar Kannan Badri Narayanan Department of Ceramic engineering National Institute of Technology Rourkela School of Chemical engineering Yeungnam University

Cerium oxide（CeO2）,or ceria,and its doped derivatives have been extensively studied for several decades and are well-known oxides valued for their unique structural properties and wide range of *** materials play a crucial role in sustainable development within *** modification through de fect e ngineering of the highly stable cubic fluorite phase enhances the versatility of this doped ceria to a new *** the numerous dopants of the CeO2matrix,ceria doped with gadolinium（Gd）,known as Ce1-xGdxO2-?（CGO）,is gaining popularity due to its *** introduction of defect-induced vacancies in the oxygen sublattice（V_o） and a change in the average valence of cerium(Ce3+/Ce4+) are primarily responsible for the improved performance compared to pristine *** materials are currently undergoing intensive research for potential use as electrolytes in intermediate-temperature solid oxide fuel cells（IT-SOFCs） and dense oxygen-permeable membranes（OPMs）.Additionally,they are being commercially utilized for power generation and oxygen *** materials are also attracting significant attention in various fields such as optics,photocatalysis,electrostriction,spintronics,gas sensing,electrocatalysis,and biomedical *** review paper aims to compile the latest contributions to CGO materials and comprehensively cover their various application *** crystal structure,defect equilibrium in Gd3+-doped CeO2,the origin of multifunctionality,and the prospects of these materials are also exclusively discussed.

关键词： Biomedicine Gadolinium-doped CeO2 Gas sensors Photo/electrocatalysts Rare earths Spintronics

A compact bimorph rotary piezoelectric actuator with customized small power supply

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Science China(Technological Sciences) 2024年第4期67卷 1185-1195页

作者： DENG Jie LIU DaQing WANG WeiYi LIU YingXiang School of Mechatronics and engineering Harbin Institute of TechnologyHarbin 150001China

Inertial piezoelectric actuators are widely applied in precision devices with simple structure and accurate ***,existing inertial piezoelectric actuators still face the challenges of rollback motion and bulky power *** this work,an alternate excitation strategy and a customized small power supply for a bimorph rotary piezoelectric actuator(BRPA)are proposed to solve the *** BRPA prototype is designed with a bipedal symmetrical structure,measuring 35 mm in height and 32 mm in diameter,which has a maximum rotation velocity of 0.247 rad/s and a resolution of 0.66μ*** to the bipedal symmetrical structure,the friction directions between the driving feet and the rotor can be coordinated to suppress the *** rollback ratio is almost zero when the phase difference of the exciting signal is set as 180°.The customized power supply is designed and manufactured,whose size is 58 mm×56 mm×46 *** can output signals for the single step mode and the continuous mode,and they are adopted to excite BRPA to achieve a small stroke with one single step and a large stroke with continuous step,***,an experimental system for optical fiber alignment is developed based on the BRPA and the customized small power supply,the experiment has verified the practicability of this work in the precision fields,especially in the miniaturized precision systems.

关键词： inertial piezoelectric actuator customized small power supply single step mode continuous mode rollback suppression miniaturized precision system

维普期刊数据库

A tendon system to re-center steel moment frames with weak stories

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Earthquake engineering and engineering Vibration 2024年第4期23卷 1057-1072页

作者： Wang Tao Wang Fei Masayoshi Nakashima institute of engineering Mechanics China Earthquake AdministrationBeijing 100190China Key Laboratory of Earthquake engineering and engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin 150080China Disaster Prevention Research institute Kyoto UniversityGokashoUjiKyoto 611-0011Japan

A wide open bottom story of a frame building is often expected by owners for use as a garage or ***,this leads to weak stories due to abrupt changes in lateral stiffness and often results in unexpected story collapse as observed in many previous *** retrofit frame buildings that have experienced weak story damage,a tendon system is proposed in this study,which consists of a set of swaying columns and *** swaying columns are used to uniformly redistribute the lateral deformation along the height,while the tendons provide extra lateral stiffness and renders the entire structural system a re-centering *** avoid unnecessary forces to swaying columns,pin-connections are used at the *** are placed over the entire story to gain large elastic *** analysis reveals that the swaying column,with a stiffness of about 0.9 times that of the weak story,and the tendons attached at the roof,with a stiffness of 0.04 times that of the weak story,can provide the optimal performance with a maximum residual story drift angle of less than 0.5%.Online hybrid tests were carried out,which demonstrated that uniformly distributed story drifts and acceptable residual deformation could be achieved by the proposed tendon system.

关键词： tendon system re-centering capability residual deformation rehabilitation collapse prevention

Quasi-periodic orbits of small solar sails with time-varying attitude around Earth–Moon libration points

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Astrodynamics 2024年第1期8卷 161-174页

作者： Toshihiro Chujo Department of Mechanical engineering School of EngineeringTokyo Institute of TechnologyTokyo152-8550Japan

This paper proposes new quasi-periodic orbits around Earth–Moon collinear libration points using solar *** including the time-varying sail orientation in the linearized equations of motion for the circular restricted three-body problem(CR3BP),four types of quasi-periodic orbits(two types around L1 and two types around L2)were *** them,one type of orbit around L2 realizes a considerably small geometry variation while ensuring visibility from the Earth if(and only if)the sail acceleration due to solar radiation pressure is approximately of a certain magnitude,which is much smaller than that assumed in several previous *** means that only small solar sails can remain in the vicinity of L2 for a long time without propellant *** orbits designed in the linearized CR3BP can be translated into nonlinear CR3BP and high-fidelity ephemeris models without losing geometrical *** this study,new quasi-periodic orbits are formulated,and their characteristics are ***,their extendibility to higher-fidelity dynamic models was verified using numerical examples.

关键词： solar sail libration point orbit Earth-Moon system circular restricted three-body problem(CR3BP)

Observation and verification of surface electrical explosion driven by radial-distributed pulsed current in laboratory lightning strike test

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High Voltage 2024年第1期9卷 137-149页

作者： Ruoyu Han Yuchen Cao Yakun Liu Xi Chen Ting Li Chen Li Pengfei Li State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijingChina School of Mechatronical engineering Beijing Institute of TechnologyBeijingChina Department of Electrical engineering Shanghai Jiaotong UniversityShanghaiChina Beijing institute of Astronautical System engineering BeijingChina Aerospace Research institute of Materials and Processing Technology BeijingChina

The laboratory lightning test is essential for assessing the effectiveness of lightning strike protection(LSP).Particularly,direct lightning strike damage can be performed with pulsed current injection into the *** paper focuses on the dynamic process of arc plasma and shock wave behaviour in the vicinity of the‘strike’point.A rod-plate discharge load is built for testing aluminium and coated plate under 40-kA-level pulsed *** visualisation of the luminous discharge plasma and its flow field via high-speed photography(from different angles)is meticulously designed and implemented,synchronised with electro-physical *** results indicate some new mechanisms for lightning strike damage,apart from the impulse heat loading from the thermal *** transient current injection through the arc root concentrates on a thin skin layer(skin-depth effect),with the radial-attenuated current density,driving asynchronously electrical explosions on the plate *** inhomogeneous Joule heating of the plate leads to outwardly propagating phase transition and shock wave along the conductive *** addition,the electro-thermal instability is observed and regarded as the seed of irregular erosion *** information reveals two different plasma states of main discharge arc channel and adjacent surface electrical *** correspondence of the physical mechanism of electrical explosion and optical radiation is *** images for different regions depict erosion characteristics and summarise influencing factors,further confirming the mechanism *** research clarifies the role of skin-depth effect in transaction arc erosion for electrode,complements the electrical explosion theory with unevenly distributed current and helps optimise strategies of LSP.

关键词： electrical lightning radial