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Controllability Gramian-based measures of graph product networks

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Science China(Information Sciences) 2024年第10期67卷 315-331页

作者： Yuequan xiang Linying xiang School of Information Science and Engineering Northeastern University School of Artificial Intelligence Tiangong University

This paper addresses the controllability measures of composite networks based on graph products, in which the graph product networks are either Kronecker product networks or Kronecker sum *** primary objective pursued here is to reveal the controllability Gramian-based measure links between the graph product composite network and its subnetworks. First, the analytical expression of the average controllability for the Kronecker product network is derived by using the corresponding controllability measures of its subnetworks. An upper bound of volumetric control energy is further obtained for the Kronecker product network. Then, the upper bounds are derived for the controllability measures of the Kronecker sum network,which provide a valuable reference for designing controllable networks in practical applications. Finally, the controllability of the Kronecker product network is compared with that of the Kronecker sum network, and it is found that when the subnetworks satisfy certain conditions, the Kronecker product network has better average controllability than the Kronecker sum network.

关键词： composite network graph product controllability Gramian-based measure average controllability control energy

Dual-ion carrier storage through Mg^(2+) addition for high-energy and long-life zinc-ion hybrid capacitor

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 179-185页

作者： Junjie Zhang xiang Wu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

Cation additives can efficiently enhance the total electrochemical capabilities of zinc-ion hybrid capacitors (ZHCs).However their energy storage mechanisms in zinc-based systems are still under ***,we modulate the electrolyte and achieve dual-ion storage by adding magnesium *** we assemble several Zn//activated carbon devices with different electrolyte concentrations and investigate their electrochemical reaction dynamic *** zinc-ion capacitor with Mg^(2+)mixed solution delivers 82 mAh·g^(-1)capacity at 1 A·g^(-1) and maintains 91%of the original capacitance after 10000 *** is superior to the other assembled zinc-ion devices in single-component *** finding demonstrates that the double-ion storage mechanism enables the superior rate performance and long cycle lifetime of ZHCs.

关键词： zinc-ion hybrid capacitor MgSO_(4) electrolyte rate performance storage mechanism

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

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China Foundry 2024年第3期21卷 221-228页

作者： Meng-xin Wang Zi-xiang Wu Jing-yu He xiang Chen School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Stainless steels are used in a wide range of complex environments due to their excellent corrosion *** stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different *** microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room *** show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of *** austenite with a lower Ni content undergoes a martensitic transformation during plastic *** tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging *** enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

关键词： multiphase stainless steel mechanical properties TRIP effect reversed austenite G-phase

Highly homogeneous zero-index metamaterials make devices more compact and perform better

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Light(Science & Applications) 2024年第5期13卷 806-807页

作者： Wei-xiang Jiang State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast University210096 NanjingChina

A highly homogeneous microwave zero-index metamaterial based on high-permittivity SrTiO3 ceramics is demonstrated to realize the small-aperture high-directivity *** a novel technique is a remarkable step forward to de... 详细信息

关键词： ceramics SrTiO3 Highly

Review of dynamics and active control of large-scale space membrane antenna

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Astrodynamics 2024年第1期8卷 1-26页

作者： xiang Liu Guoping Cai Department of Engineering Mechanics MOE Key Laboratory of HydrodynamicsChongqing Research InstituteShanghai Jiao Tong UniversityShanghai200240China

Large-scale space membrane antennas have significant potential in satellite communication,space-based early warning,and Earth *** of their large size and high flexibility,the dynamic analysis and control of membrane antenna are *** maintain the working performance of the antenna,the pointing and surface accuracies must be strictly ***,the accurate dynamic modeling and effective active control of large-scale space membrane antennas have great theoretical significance and practical value,and have attracted considerable interest in recent *** paper reviews the dynamics and active control of large-scale space membrane ***,the development and status of large-scale space membrane antennas are ***,the key problems in the dynamics and active control of large membrane antennas,including the dynamics of wrinkled membranes,large-amplitude nonlinear vibration,nonlinear model reduction,rigid-flexible-thermal coupling dynamic modeling,on-orbit modal parameter identification,active vibration control,and wave-based vibration control,are discussed in ***,the research outlook and future trends are presented.

关键词： large-scale space membrane antenna dynamicmodeling active control

Frost heaving and crack initiation characteristics of tunnel rock mass in cold regions under low-temperature degradation

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Journal of Mountain Science 2024年第8期21卷 2844-2854页

作者： CHEN Wenhua xiang Tian School of Civil Engineering Beijing Jiaotong UniversityBeijing 202303China

Water freezing in rock fractures causes volumetric expansion and fracture development through frost *** study introduces a novel analytical model to investigate how uneven freezing force and surrounding rock pressure influence fracture initiation,based on mass conservation,elasticity,and water-ice phase transition principles.A model for rock fracture initiation considering freezing temperature,uneven freezing expansion,in-situ stress,and lateral pressure was proposed based on fracture *** for stress intensity factors were developed and validated using the phase field *** effects of rock elastic modulus anisotropy and critical fracture energy density on fracture initiation were also *** results show that the values of KI and KII exhibit an upward trend as the freezing temperature,uneven expansion,in-situ stress,and lateral pressure *** uneven freezing expansion has the most significant influence on KI and KII values among these *** the uneven freezing expansion coefficient increases to 0.5,the fracture initiation mode shifts from tensile fracture to shear *** the lateral pressure coefficient increases to 1,the fracture initiation mode shifts from tensile fracture to shear *** elastic modulus anisotropy causes fractures to propagate in a clockwise direction,forming a'butterfly'*** fracture energy density an isotropy causes counterclockwise deviation in propagation direction,resulting in branching paths and an'H'-shaped pattern.

关键词： Rock fractures Fracture water Uneven freezing expansion Phase field method Initiation angle Anisotropy

Thermal fatigue and wear of compacted graphite iron brake discs with various thermomechanical properties

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China Foundry 2024年第3期21卷 248-256页

作者： Gui-quan Wang Zhuo Xu Zhong-li Liu xiang Chen Yan-xiang Li School of Nuclear Equipment and Nuclear Engineering Yantai UniversityYantai 264005ShandongChina School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

The increase in payload capacity of trucks has heightened the demand for cost-effective yet high performance brake *** this work,the thermal fatigue and wear of compacted graphite iron brake discs were investigated,aiming to provide an experimental foundation for achieving a balance between their thermal and mechanical *** graphite iron brake discs with different tensile strengths,macrohardnesses,specific heat capacities and thermal diffusion coefficients were produced by changing the proportion and strength of *** peak temperature,pressure load and friction coefficient of compacted graphite iron brake discs were analyzed through inertia friction *** morphology of thermal cracks and 3D profiles of the worn surfaces were also *** is found that the thermal fatigue of compacted graphite iron discs is determined by their thermal properties.A compacted graphite iron with the highest specific heat capacity and thermal diffusion coefficient exhibits optimal thermal fatigue *** of the matrix at low temperatures significantly weakens the function of alloy strengthening in hindering the propagation of thermal *** the reduced hardness,increasing the ferrite proportion can mitigate wear loss resulting from low disc temperatures and the absence of abrasive wear.

关键词： compacted graphite iron brake disc thermomechanical properties thermal fatigue wear

An integrative mathematical model of microwave ion thruster for mHz-frequency thrust noise analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 121-136页

作者： xiang NIU Hui LIU Daren YU Plasma Propulsion Laboratory Harbin Institute of TechnologyHarbin 150001China

Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.

关键词： Electric propulsion Microwave ion thruster Integrative model Sheath property Ion beamlet divergence Thrust noise Plasma

Coordination for a Closed-loop Supply Chain with Recycling Platform Considering Dynamic Setting

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Journal of Systems Science and Systems Engineering 2024年第4期33卷 425-451页

作者： Zehua xiang Ting Ji Lingfeng Dong School of Management Zhejiang UniversityHangzhou310058China School of Business Hangzhou City UniversityHangzhou310015China Alibaba Business College Hangzhou Normal UniversityHangzhou311121China

This paper presents a dynamic closed-loop supply chain(CLSC)model,incorporating a manufacturer,a retailer,and an internet recycling platform(IRP),utilizing differential game theory while considering the forgetting effect of *** model encompasses factors such as the quality level of used products and Big Data marketing(BDM),comparing optimal equilibriums under decentralized and cooperative decision *** effectively coordinate the dynamic CLSC at each time point,we propose a revenue-sharing and cost-sharing(RSCS)combined *** addition to ensuring reasonable sharing of revenues and costs,this contract allows the manufacturer to flexibly adjust wholesale prices for final products and transfer prices for used products in order to distribute profits appropriately and achieve Pareto optimality within the CLSC ***,our results indicate that there exists a threshold for Big Data marketing efficiency;high-efficiency BDM not only facilitates increased recycling on Internet platforms but also reduces unit recycling costs for ***,when implementing the combined contract,Big Data marketing efficiency does not impact the transfer price paid by manufacturers to Internet recycling platforms.

关键词： Big Data marketing differential game closed-loop supply chain coordination internet recycling platform