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VN nanoparticle-assembled hollow microspheres/N-doped carbon nanofibers:An anode material for superior potassium storage

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Nano Materials Science 2022年第2期4卷 104-112页

作者： Ya Ru Pei Ming Zhao Yu Peng Zhu Chun Cheng Yang Qing Jiang Key Laboratory of Automobile Materials(Jilin University) Ministry of Educationand School of Materials Science and EngineeringJilin UniversityChangchun130022China

Thanks to inexpensive and bountiful potassium resources,potassium ion batteries(PIBs)have come into the spotlight as viable alternatives for next-generation battery systems.However,poor electrochemical kinetics due to the large size of the K^(+) is a major challenge for PIB anodes.In this paper,an ingenious design of VN nanoparticleassembled hollow microspheres within N-containing intertwined carbon nanofibers(VN-NPs/N-CNFs)via an electrospinning process is reported.Employed as PIB anodes,VN-NPs/N-CNFs exhibit a superb rate property and prolonged cyclability,surpassing that of other reported metal nitride-based anodes.This is ascribed to:(i)the VN NP-assembled hollow microspheres,which shorten the K^(+) diffusion distance,and mitigate volume expansion;and(ii)the interconnected N-CNFs,which supply numerous active sites for K^(+) adsorption and facilitate rapid electron/ion transport.

关键词： Potassium-ion batteries VN nanoparticles N-doped carbon nanofibers Hollow microspheres

Active disturbance rejection control for fractional reaction-diffusion equations with spatially varying diffusivity and time delay

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Science China(Information Sciences) 2022年第2期65卷 254-256页

作者： Rui-yang CAI Hua-cheng ZHOU chun-Hai KOU College of Information Science and Technology Donghua University School of Mathematics and Statistics Central South University Department of Applied Mathematics Donghua University

Dear editor,Fractional systems have been identified as an excellent tool for describing sub-diffusion phenomena owing to the memory property of the fractional derivatives.Among all the research fields in the control theory of fractional systems,stabilization occupies an important place.Ref.[1]discussed the boundary stabilization for fractional PDEs (partial differential equations) for the first time,where a feedback controller was designed to stabilize fractional wave equations using numerical methods,

关键词： Boundary control active disturbance rejection control backstepping method fractional Mittag-Leffler stable

Numerical Implementation of a Unified Viscoplastic Model for Considering Solder Joint Response under Board-Level Temperature Cycling

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Computer Modeling in Engineering & Sciences 2021年第8期128卷 639-668页

作者： Hung-chun yang Tz-cheng Chiu Department of Mechanical Engineering National Cheng Kung UniversityTainan701Taiwan

An implicit integration scheme was developed for simulating the viscoplastic constitutive behavior ofSn3.0Ag0.5Cu solder and programmed into a user material subroutine of the finite element software ANSYS. Thenumerical procedure first solves the essential state variables by using a three-level iterative procedure, and updatesthe remaining stress and state variables accordingly. The numerical implementation was applied to consider theresponses of solder joints in an electronic assembly under temperature cycling condition. The viscoplastic strainenergy density accumulation over one temperature cycle was identified as a feasible parameter for evaluating thethermomechanical reliability of the solder joints.

关键词： Pb-free hysteresis ratcheting fatigue tangent modulus

Wall-modeled large eddy simulation for the flows around an axisymmetric body of revolution

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Journal of Hydrodynamics 2023年第2期35卷 199-209页

作者： Song-tao Chen Lu-chun yang Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Wuhan Second Ship Design and Research Institute Wuhan430205China

The flow around an axisymmetric body of revolution(DARPA SUBOFF bare model)at Re=1.2×10^(7)is numerically investigated using the wall-modeled large eddy simulation(WMLES).To evaluate the capabilities of WMLES in such wall-bounded turbulent flows,the effects of the wall stress model and sampling distance are systematically studied.The numerical results of the non-equilibrium wall stress model with an appropriate sampling distance are in good agreement with the experiments in terms of pressure coefficient,skin-friction coefficient,and drag coefficient.On this basis,the thickening of the turbulent boundary layer and the expansion of the wake can be clearly observed through flow visualization,especially using the Liutex vortex identification method.

关键词： Wall-modeled large eddy simulation(WMLES) axisymmetric body of revolution wall stress model sampling distance Liutex SUBOFF

A Coordination-Based Algorithm for Dedicated Destination Vehicle Routing in B2B E-Commerce

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Computer Systems Science & Engineering 2022年第3期40卷 895-911页

作者： Tsung-Yin Ou Chen-yang cheng chun Hsiung Lai Hsin-Pin Fu Department of Marketing and Distribution Management National Kaohsiung University of Science and TechnologyTaiwan Department of Industrial Engineering and Management Taipei University of TechnologyTaiwan Department of Enterprise Information and Industrial Engineering Tunghai UniversityTaiwan

This paper proposes a solution to the open vehicle routing problem with time windows(OVRPTW)considering third-party logistics(3PL).For the typical OVRPTW problem,most researchers consider time windows,capacity,routing limitations,vehicle destination,etc.Most researchers who previously investigated this problem assumed the vehicle would not return to the depot,but did not consider its final destination.However,by considering 3PL in the B2B e-commerce,the vehicle is required back to the nearest 3PL location with available space.This paper formulates the problem as a mixed integer linear programming(MILP)model with the objective of minimizing the total travel distance.A coordinate representation particle swarm optimization(CRPSO)algorithm is developed to obtain the best delivery sequencing and the capacity of each vehicle.Results of the computational study show that the proposed method provides solution within a reasonable amount of time.Finally,the result compared to PSO also indicates that the CRPSO is effective.

关键词： Third-party logistics open vehicle routing problem with time windows dedicated destination Notations

High-performance anode materials for Na-ion batteries

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Rare Metals 2018年第3期37卷 167-180页

作者： De-Liang cheng Li-chun yang Min Zhu Key Laboratory of Advanced Energy Storage Materials of Guangdong Province School of Materials Science and EngineeringSouth China University of Technology

Na-ion batteries are considered a promising alternative to Li-ion batteries for large-scale energy storage systems due to their low cost and the natural abundance of Na resource. Great effort is making worldwide to develop high-performance electrode materials for Na-ion batteries,which is critical for Na-ion batteries. This review provides a comprehensive overview of anode materials for Na-ion batteries based on Na-storage mechanism： insertion-based materials, alloy-based materials, conversion-based materials and organic composites. And we summarize the Nastorage mechanism of those anode materials and discuss their failure mechanism. Furthermore, the problems and challenges associated with those anodes are pointed out,and feasible strategies are proposed for designing highperformance anode materials. According to the current state of research, the search for suitable anode materials for Na-ion batteries is still challenging although substantial progress has been achieved. Nevertheless, we believe that high-performance Na-ion batteries would be promising for practical applications in large-scale energy storage systems in the near future.

关键词： Na-ion batteries Anode materials Na-storage mechanism

Background knowledge based privacy metric model for online social networks

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The Journal of China Universities of Posts and Telecommunications 2014年第2期21卷 75-82页

作者： cheng cheng ZHANG chun-hong JI yang School of Information and Communication Engineering Beijing University of Posts and Telecommunications

The data of online social network （OSN） is collected currently by the third party for various purposes. One of the problems in such practices is how to measure the privacy breach to assure users. The recent work on OSN privacy is mainly focus on privacy-preserving data publishing. However, the work on privacy metric is not systematic but mainly focus on the traditional datasets. Compared with the traditional datasets, the attribute types in OSN are more diverse and the tuple is relevant to each other. The retweet and comment make the graph character of OSN notably. Furthermore, the open application programming interfaces （APIs） and lower register barrier make OSN open environment, in which the background knowledge is more easily achieved by adversaries. This paper analyzes the background knowledge in OSN and discusses its characteristics in detail. Then a privacy metric model faces OSN background knowledge based on kernel regression is proposed. In particular, this model takes the joint attributes and link knowledge into consideration. The effect of different data distributions is discussed. The real world data set from *** has been adopted. It is demonstrated that the privacy metric algorithm in this article is effective in OSN privacy evaluation. The prediction error is 30% lower than that of the work mentioned above

关键词： privacy metric social network background knowledge kernel regression

Effect of vortex dynamics and instability characteristics on the induced drag of trailing vortices

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Chinese Journal of Aeronautics 2022年第9期35卷 160-173页

作者： Zepeng cheng Shiyan ZHANG yang XIANG chun SHAO Miao ZHANG Hong LIU Yingchun CHEN School of Aeronautics and Astronautics Shanghai Jiao Tong UniversityShanghai 200240China Shanghai Aircraft Design and Research Institute Commercial Aircraft Corporation of China Ltd.Shanghai 201210China

In this paper, trailing vortices generated by three wingtip configurations, namely the M6wing and the M6 wing with a blended or split winglet, are experimentally investigated using the Stereo Particle Image Velocimetry(SPIV) technology. Then, linear stability analysis is performed to investigate instability characteristics. Three corresponding trailing vortex patterns, including the isolated trailing vortex without wake(pattern v) and with wake(pattern v-w), co-rotating vortex pair(pattern v-v), are observed in experiments. The strength of trailing vortices, characterized by circulation, is reduced after installing winglets as expected, and the strength of pattern v-v can be further suppressed compared with pattern v-w. Moreover, instability characteristics, such as the eigenvalue spectrum and perturbation mode, are distinctive among these three vortex patterns.The distribution of eigenvalue spectrums indicates that pattern v and pattern v-w are temporally“marginally stable”, while pattern v-v is temporally “unstable.” The primary perturbation mode of pattern v and pattern v-w is the m =-1 helical mode, while |m|>1 for the case of pattern v-v.The effect of vortex dynamics and instability characteristics can be concluded in two aspects.Firstly, the value of induced drag is polluted by about 3% from vortex wandering since vortex wandering affects the tangential velocity and streamwise vorticity of trailing vortices. Secondly, the growth rate and penetration depth perturbation mode affect trailing vortex evolution and further affect induced drag. Specifically, the larger the growth rate and penetration depth are, the more turbulence injects inside the vortex core, thus leading to a quicker and more intense attenuation of trailing vortex, as well as a smaller induced drag. This finding can guide us to manipulate the induced drag in flow control.

关键词： Induced drag Linear stability analysis SPIV Trailing vortex Vortex flow Winglet

Acoustic skin meta-muffler

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Science China(Physics,Mechanics & Astronomy) 2021年第9期64卷 87-92页

作者： Yong-Xin Gao Yi cheng Bin Liang Yong Li Jing yang Jian-chun cheng Key Laboratory of Modern Acoustics Ministry of EducationInstitute of AcousticsDepartment of PhysicsNanjing UniversityNanjing 210093China Collaborative Innovation Center of Advanced Microstructures Nanjing UniversityNanjing 210093China Institute of Acoustics School of Physics Science and EngineeringTongji UniversityShanghai 200092China

The effective elimination of sound energy traveling in open ducts is critical in acoustics,with considerable potential in diverse applications ranging from duct noise control to exhaust system design.However,previous absorber mechanisms are bulky or have limited ventilation or unsatisfactory absorption capability.We propose and experimentally demonstrate the concept of meta-mufflers capable of quasi-perfectly absorbing airborne sound propagating in an open duct while minimizing the influence on airflow because of its vanishing thickness.The mechanism uses coupling among asymmetric metasurfaces to achieve impedance match and subsequent high absorption in a subwavelength scale,which is explained analytically and validated experimentally.The proposed meta-muffler features an uncomplicated design,high attenuation efficiency,and a thickness of nearly two orders of magnitude of wavelength,ensuring the free pass of other entities.Furthermore,our design offers the flexibility of tuning and extending working bandwidth by hybridization of weak resonances.The performance of the proposed muffler is verified via experiments,which correlate excellently with theoretical predictions.The realization of meta-mufflers opens a route to novel acoustic absorbers and could have far-reaching implications in a plethora of important scenarios calling for both perfect sound absorption and open acoustic paths.

关键词： acoustic metamaterial ultrathin sound absorber coupling effect broadband high absorption