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Multi-scale Modeling and Finite Element Analyses of Thermal Conductivity of 3D C/SiC Composites Fabricating by Flexible-Oriented Woven Process

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 275-288页

作者： Zheng Sun Zhongde Shan Hao Huang Dong Wang Wang Wang Jiale Liu Chenchen Tan Chaozhong Chen Nanjing University of Aeronautics and Astronautics Nanjing 210016China School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China CRRC institute corporation limited Beijing 100070China

Thermal conductivity is one of the most significant criterion of three-dimensional carbon fiber-reinforced SiC matrix composites(3D C/SiC).Represent volume element(RVE)models of microscale,void/matrix and mesoscale proposed in this work are used to simulate the thermal conductivity behaviors of the 3D C/SiC *** entirely new process is introduced to weave the preform with three-dimensional orthogonal *** 3D steady-state analysis step is created for assessing the thermal conductivity behaviors of the composites by applying periodic temperature boundary *** RVE models of cuboid,hexagonal and fiber random distribution are respectively developed to comparatively study the influence of fiber package pattern on the thermal conductivities at the ***,the effect of void morphology on the thermal conductivity of the matrix is analyzed by the void/matrix *** prediction results at the mesoscale correspond closely to the experimental *** effect of the porosities and fiber volume fractions on the thermal conductivities is also taken into *** multi-scale models mentioned in this paper can be used to predict the thermal conductivity behaviors of other composites with complex structures.

关键词： 3D C/SiC composites Finite element analyses Multi-scale modeling Thermal conductivity

Damage Evolution of Ballastless Track Concrete Exposed to Flexural Fatigue Loads:The Application of Ultrasonic Pulse Velocity,Impact-echo and Surface Electrical Resistance Method

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 353-363页

作者：杨志强李化建 WEN Jiaxing DONG Haoliang HUANG Fali WANG Zhen YI Zhonglai Railway Engineering research institute China Academy of Railway Science Corporation LimitedBeijing 100081China State Key Laboratory for Track System of High-Speed Railway Beijing 100081China School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China

In order to clarify the fatigue damage evolution of concrete exposed to flexural fatigue loads,ultrasonic pulse velocity(UPV),impact-echo technology and surface electrical resistance(SR) method were *** variable based on the change of velocity of ultrasonic pulse(Du) and impact elastic wave(Di)were defined according to the classical damage *** influences of stress level,loading frequency and concrete strength on damage variable were *** experimental results show that Du and Di both present a three-stages trend for concrete exposed to fatigue *** impact elastic wave is more sensitive to the microstructure damage in stage Ⅲ,the critical damage variable,i e,the damage variable before the final fracture of concrete of Di is slightly higher than that of ***,the evolution of SR of concrete exposed to fatigue loads were analyzed and the relationship between SR and Du,SR and Di of concrete exposed to fatigue loads were *** is found that the SR of concrete was decreased with the increasing fatigue cycles,indicating that surface electrical resistance method can also be applied to describe the damage of ballastless track concrete exposed to fatigue loads.

关键词： ballastless track fatigue damage ultrasonic pulse velocity impact-echo surface electrical resistance

Evolution of Cenozoic sedimentary architecture in Central and Southern South china Sea basins

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Journal of Palaeogeography 2024年第1期13卷 35-53页

作者： Wu Tang Xiao-Jun Xie Yi-Bo Wang Lian-Qiao Xiong Jia Guo Xin Li china National Offshore Oil corporation research institute Beijing 100028China

The Central and Southern South china Sea(CSSCS) has a complex tectonic dynamic background and abundant oil and gas resources, which has always been a hot topic of academic and industrial ***, systematic analyses are still lacking regarding its sediment filling structure and evolution, mostly due to limited borehole penetration and poor quality of seismic reflection data for deeply buried sequences. No consensus has been reached yet on the sedimentary infilling processes, which impeded the reconstruction of the palaeogeography of Southeast Asia and the oil-and-gas exploration undertakings. Here, we illustrate the Cenozoic sedimentary evolution of the CSSCS region by synthesizing relevant data from previous literature and our own observations and displaying the evolution of depositional systems in sequential reconstructions. Besides, the controlling factors of preferred sedimentary scenarios in the CSSCS incorporate the latest interpretations of the spreading of South china Sea(SCS) as well as the demise of the hypothetical Proto-South china Sea(PSCS). The results show that there are three types of sedimentary basins in the CSSCS(foreland,strike-slip, and rift basins) with different sedimentary filling structures. The foreland basins formed a depositional pattern of ‘transition from deep water to shallow water environments', dominated by deep-water depositional systems which were formed before the Early Oligocene with submarine fans developed. Later,the foreland basins were gradually dominated by shallow-water depositional systems with deltas and shallow marine facies. The strike-slip basins showed the depositional architecture of ‘transition from lake to marine environments', i.e. the basins were dominated by lacustrine deposits during the Eocene and evolved into the marine depositional environment since Oligocene with delta developed in the western part of the basin. The depositional evolution of rift basins illustrated the characteristics of 'transiti

关键词： Central and Southern South china Sea Sedimentary filling Main controlling factors Proto-South china Sea South china Sea

Experimental and Numerical Investigation on the Aerodynamic Characteristics of High-Speed Pantographs with Supporting Beam Wind Deflectors

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Fluid Dynamics & Materials Processing 2024年第1期20卷 127-145页

作者： Shiyang Song Tongxin Han Postgraduate Department China Academy of Railway SciencesBeijing100081China Locomotive&Car research institute China Academy of Railway Sciences Corporation LimitedBeijing100081China

Aiming to mitigate the aerodynamic lift force imbalance between pantograph strips,which exacerbates wear and affects the current collection performance of the pantograph-catenary system,a study has been conducted to support the beam deflector optimization using a combination of experimental measurements and computational fluid dynamics(CFD)*** results demonstrate that the size,position,and installation orientation of the wind deflectors significantly influence the amount of force *** also indicate that the front strip deflectors should be installed downwards and the rear strip deflectors upwards,thereby forming a“π”***,the lift force compensation provided by the wind deflectors increases with the size of the *** wind compensation strategies,such as control circuits,are also discussed,putting emphasis on the pros and cons of various pantograph types and wind compensation approaches.

关键词： High-speed pantograph aerodynamic lift force supporting beam wind deflectors computational fluid dynamics(CFD)

Investigation on Magnetorheological Effect of Novel Self-healing Magnetorheological Elastomers

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china Petroleum Processing & Petrochemical Technology 2024年第2期26卷 88-97页

作者： Wang Deping Wang Jing Wang Xin Noman Tariq Yu Zhen Zheng Wenbo Wei Yintao General research and Development institute China FAW Corporation LimitedChangchun 130013 China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China

Magnetorheological elastomers(MREs)hold significant promise in various fields such as automotive engineering,and civil engineering,where they serve as intelligent *** on the application of an external magnetic field,these materials exhibit varying magnetorheological and viscoelastic properties,including shear stress,yield stress,dynamic moduli,and *** this work,a new type of MRE,termed self-healing MREs(SH-MREs),has been developed by adding a novel self-healing agent into existing *** dynamic modulus and loss factor of SH-MREs with different compositions have been characterized under various conditions of frequency,temperature,and *** results show that as the strain value increases,the loss factor also ***,the loss factor initially increases and then decreases with increasing magnetic field *** higher concentrations of ferromagnetic particles increase the loss factor,they enhance the operational range due to their better responsiveness to magnetic ***-MREs demonstrate improved damping capabilities,attributed to the formation of coordination bonds between ferromagnetic particles and the self-healing *** stable structure increases the viscosity of *** results of the regression model suggest a direct proportionality between sensitivity to the magnetic field and the ferromagnetic particle concentration.

关键词： magnetorheological elastomer magnetorheological effect storage modulus loss factor

Reputation-based joint optimization of user satisfaction and resource utilization in a computing force network

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Frontiers of Information Technology & Electronic Engineering 2024年第5期25卷 685-700页

作者： Yuexia FU Jing WANG Lu LU Qinqin TANG Sheng ZHANG china Mobile research institute Beijing 100053China Purple Mountain Laboratories Nanjing 211111China china Mobile Communications corporation Beijing 100033China

Under the development of computing and network convergence,considering the computing and network resources of multiple providers as a whole in a computing force network(CFN)has gradually become a new ***,since each computing and network resource provider(CNRP)considers only its own interest and competes with other CNRPs,introducing multiple CNRPs will result in a lack of trust and difficulty in unified *** addition,concurrent users have different requirements,so there is an urgent need to study how to optimally match users and CNRPs on a many-to-many basis,to improve user satisfaction and ensure the utilization of limited *** this paper,we adopt a reputation model based on the beta distribution function to measure the credibility of CNRPs and propose a performance-based reputation update ***,we formalize the problem into a constrained multi-objective optimization problem and find feasible solutions using a modified fast and elitist non-dominated sorting genetic algorithm(NSGA-II).We conduct extensive simulations to evaluate the proposed *** results demonstrate that the proposed model and the problem formulation are valid,and the NSGA-II is effective and can find the Pareto set of CFN,which increases user satisfaction and resource ***,a set of solutions provided by the Pareto set give us more choices of the many-to-many matching of users and CNRPs according to the actual situation.

关键词： Computing force network Resource scheduling Performance-based reputation User satisfaction

Implication of community-level ecophysiological parameterization to modelling ecosystem productivity:a case study across nine contrasting forest sites in eastern china

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Journal of Forestry research 2024年第1期35卷 1-11页

作者： Minzhe Fang Changjin Cheng Nianpeng He Guoxin Si Osbert Jianxin Sun School of Ecology and Nature Conservation Beijing Forestry UniversityBeijing 100083China research institute of Energy Saving Environmental ProtectionOccupational Safety and HealthChina Academy of Railway Sciences Corporation LimitedBeijing 100081China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 100049China

Parameterization is a critical step in modelling ecosystem ***,assigning parameter values can be a technical challenge for structurally complex natural plant communities;uncertainties in model simulations often arise from inappropriate model *** we compared five methods for defining community-level specific leaf area(SLA)and leaf C:N across nine contrasting forest sites along the North-South Transect of Eastern china,including biomass-weighted average for the entire plant community(AP_BW)and four simplified selective sampling(biomass-weighted average over five dominant tree species[5DT_BW],basal area weighted average over five dominant tree species[5DT_AW],biomass-weighted average over all tree species[AT_BW]and basal area weighted average over all tree species[AT_AW]).We found that the default values for SLA and leaf C:N embedded in the Biome-BGC v4.2 were higher than the five computational methods produced across the nine sites,with deviations ranging from 28.0 to 73.3%.In addition,there were only slight deviations(<10%)between the whole plant community sampling(AP_BW)predicted NPP and the four simplified selective sampling methods,and no significant difference between the predictions of AT_BW and AP_BW except the Shennongjia *** findings in this study highlights the critical importance of computational strategies for community-level parameterization in ecosystem process modelling,and will support the choice of parameterization methods.

关键词： Biome-BGC Community traits Forest Ecosystems Model parameterization

Phase-engineering modulation of Mn-based oxide cathode for constructing super-stable sodium storage

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Journal of Energy Chemistry 2024年第1期88卷 421-427,I0010页

作者： Quanqing Zhao Ruru Wang Ming Gao Bolin Liu Jianfeng Jia Haishun Wu Youqi Zhu Chuanbao Cao Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education School of Chemistry and Materials ScienceShanxi Normal UniversityTaiyuan 030032ShanxiChina Metals and Chemistry research institute China Academy of Railway Sciences Corporation LimitedBeijing 100081China research Center of Materials Science Beijing Key Laboratory of Construction Tailorable Advanced Functional Materials and Green ApplicationsBeijing Institute of TechnologyBeijing 100081China

The Mn-based oxide cathode with enriched crystal phase structure and component diversity can provide the excellent chemistry structure for Na-ion ***,the broad application prospect is obstructed by the sluggish Na^(+)kinetics and the phase transitions upon ***,we establish the thermodynamically stable phase diagram of various Mn-based oxide composites precisely controlled by sodium content tailoring strategy coupling with co-doping and solid-state *** chemical environment of the P2/P'3 and P2/P3 biphasic composites indicate that the charge compensation mechanism stems from the cooperative contribution of anions and *** from the no phase transition to scavenge the structure strain,P2/P'3 electrode can deliver long cycling stability(capacity retention of 73.8%after 1000 cycles at 10 C)and outstanding rate properties(the discharge capacity of 84.08 mA h g^(-1)at 20 C)than P2/P3 ***,the DFT calculation demonstrates that the introducing novel P'3 phase can significantly regulate the Na^(+)reaction dynamics and modify the local electron configuration of *** effective phase engineering can provide a reference for designing other high-performance electrode materials for Na-ion batteries.

关键词： Sodium ion battery Oxide cathode Phase engineering Phase diagram Na~+kinetic

research and application of key technologies for data delivery in railway engineering design based on metadata

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High-Speed Railway 2024年第1期2卷 51-56页

作者： Xiangru Lyu Xunxiao Yin Kun Wang Yongwen Wei institute of Computing Technologies China Academy of Railway Sciences Corporation LimitedBeijing 100081China

In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design *** railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application *** on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application *** railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced *** platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.

关键词： Railway engineering Metadata Data delivery Collaborative designplatform Design results BIM services