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Bounded Tiles in ■_p are Compact Open Sets

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Acta Mathematica Sinica,English Series 2020年第2期36卷 189-195页

作者： Ai Hua fan Shi Lei fan LA MFA UMR 7352 CNRSUniversity of Picardie33 rue Saint Leu80039 AmiensFrance School of Mathematics and Statistics&Hubei Key Laboratory of Mathematical Sciences Central China Normal UniversityWuhan430079P.R.China

Any bounded tile of the field Qp of p-adic numbers is a compact open set up to a set of zero Haar *** this note,we present two simple and direct proofs of this fact.

关键词： p-adic field tile bounded compact open

Normal Contact Model for Elastic and Plastic Mechanics of Rough Surfaces

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Acta Mechanica Solida Sinica 2019年第2期32卷 148-159页

作者： Dong Wang Zhousuo Zhang fan Jin Xuanhua fan State Key Laboratory for Manufacturing and Systems Engineering School of Mechanical Engineering XVan Jiaotong University Xi'an 710049 China Institute of Systems Engineering China Academy of Engineering Physics Mianyang 621999 China

An elastic and plastic mechanical model is proposed to characterize the normal contact of rough surfaces. The contact process is considered as three separated contact regimes, i.e., the fully elastic, mixed elastic一plastic and fully plastic ones. The Hertzian elastic contact solutions and the classical fully plastic contact model of Abbott and Fires tone are used to model the contact behaviors of fully elastically deformed asperities and fully plastically deformed ones, respectively. For the mixed elastic-plastic regime, an improved Hermit interpolation method is applied to enforce the continuity and smoothness at the critical contact interference, and to decrease the interpolation waving effect by transforming the physical quantities of contact load into logarithmic coordinates. The contac t model of rough surfaces is formula ted by using the Greenwood and Williamson^ statistics analysis. Comparisons with the CEB, ZMC and KE models are then performed to examine the effects of plasticity index and mean separation. Agreeing well with the ZMC model, our results show that the total contact load of rough surfaces decreases with the increase in mean separation, and the difference between the prediction results of elastic models and the plastic ones also decreases, indicating that the contact behaviors mainly dominated by plastically deformed asperities have been changed to be controlled by elastically deformed ones. Larger plasticity index represents more plastically deformed asperities, inducing normal contact behaviors mainly dominated by plastic solutions.

关键词： Rough surfaces Elastic plastic Asperity contact Logarithm transformation Statistics analysis

Angular Momentum-Phase Coherent State for an Electron in Uniform Magnetic Field

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Chinese Physics Letters 2001年第3期18卷 319-321页

作者： fan Hong-Yi fan Yue Department of Material Science and Engineering University of Science and Technology of ChinaHefei 230026

Based on the newly constructed state|l,r>>[fan et al.,***.16(1999)706],where l is the angular mometum quantum number and r denotes the electron's orbit radius in a uniform magnetic field,we propose a new angular momentum-phase coherent state by introducing a new operator A.A and A^(†)are annihilation and creation operator in the|l,r>>space,*** coherent state is A's eigenket and possesses non-orthonormal and overcomplete properties,it is constructed on the certain superposition of zero-angular momentum states along the radius direction.

关键词： radius angular momentum

Influence of Wall Effect on Comprehensive Controllability for Ducted fan Aircraft

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Journal of Beijing Institute of Technology 2020年第4期29卷 581-591页

作者： Tianfu Ai Changle Xiang Bin Xu Wei fan Yibo Zhang Vehicle Research Center School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

A novel coaxial ducted fan structure aircraft is proposed to enable the aircraft near vertical walls at high *** state space equation of the system can be obtained by correlation deduction and identification of the whole prototype *** on the duct test bench experiment and computational fluid dynamics(CFD)simulation analysis,the expressions between the different distances dWE from the rotor center of the prototype to the wall and the thrust,reaction torque,and tilting moment of the system under hovering conditions are *** influence of the wall effect of the prototype is incorporated into the system model to analyze the relationship between distance dWE and the comprehensive controllability of the *** results show that the system comprehensive controllability vector of other channels changes little with the decrease of the distance dWE,and only the controllability vector of the rolling channel increases *** the same time,the tilting moment also increases significantly,which strengthens the tendency of the prototype to tilt towards the wall.

关键词： coaxial ducted fan aircraft hovering condition wall effect tilting moment comprehensive controllability analysis

A Multilevel Splitting Algorithm for Quick Sampling

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Tsinghua Science and Technology 2021年第4期26卷 417-425页

作者： Liping Wang Wenhui fan Department of Automation Tsinghua UniversityBeijing 100084China

To reduce intermediate levels of splitting process and enhance sampling accuracy, a multilevel splitting algorithm for quick sampling is proposed in this paper. Firstly, the selected area of the elite set is expanded to maintain the diversity of the samples. Secondly, the combined use of an adaptive difference evolution algorithm and a local searching algorithm is proposed for the splitting procedure. Finally, a suite of benchmark functions are used for performance testing. The results indicate that the convergence rate and stability of this algorithm are superior to those of the classical importance splitting algorithm and an adaptive multilevel splitting algorithm.

关键词： rare event simulation splitting method elite set adaptive differential evolution local searching

Optimal resource allocation for transmission diversity in multi-radio access networks:a coevolutionary genetic algorithm approach

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Science China(Information Sciences) 2014年第2期57卷 99-112页

作者： fan WenHao LIU YuanAn WU fan Beijing Key Laboratory of Work Safety Intelligent Monitoring Beijing University of Posts and Telecommunications Wireless Communications and EMC Laboratory School of Electronic EngineeringBeijing University of Posts and Telecommunications

The next generation wireless communication systems aim at supporting enhanced diversified network access and data transmission abilities via the cooperative integration and unified management of various radio access technologies(RATs).The resource allocation is the core component leading the network system and mobile terminals to the service robustness and performance *** this paper,a numeric optimization model for optimizing terminals’transmission power and allocated RAT bandwidth for maximizing system capacity is proposed with the focal consideration of the multi-radio transmission diversity for parallel transmission through multiple links from diferent RATs,and diferent terminal characteristics on RAT ***,we design a centralized and periodic scheduling algorithm including an improved coevolutionary genetic algorithm for efciently solving the optimization *** results demonstrate that our propose algorithm can distinctly enhance the system performance and improve the computational efciency.

关键词： multi-radio access radio resource management multi-radio transmission diversity Lagrangian method coevolutionary algorithm genetic algorithm

Intricate evolutions of multiple-period post-buckling patterns in bilayers

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Science China(Physics,Mechanics & Astronomy) 2021年第1期64卷 72-81页

作者： Zhe Cheng fan Xu Institute of Mechanics and Computational Engineering Department of Aeronautics and AstronauticsFudan UniversityShanghai200433China

Surface instability of compliant film/substrate bilayers has raised considerable interests due to its broad applications such as wrinkle-driven surface renewal and antifouling,shape-morphing for camouflaging skins,and micro/nano-scale surface patterning ***,it is still a challenge to precisely predict and continuously trace secondary bifurcation transitions in the nonlinear post-buckling ***,we develop lattice models to precisely capture the nonlinear morphology evolution with multiple mode transitions that occur in the film/substrate *** on our models,we reveal an intricate post-buckling phenomenon involving successive flat-wrinkle-doubling-quadrupling-fold ***-stretch and pre-compression of the substrate,as well as bilayer modulus ratio,can alter surface morphology of film/substrate *** high substrate pre-tension,hierarchical wrinkles emerge in the bilayer with a low modulus ratio,while a wrinkle-to-ridge transition occurs with a high modulus ***,with moderate substrate pre-compression,the bilayer eventually evolves into a period-tripling *** diagrams based on neo-Hookean and Arruda-Boyce constitutions are drawn to characterize the influences of different factors and to provide an overall view of ultimate pattern *** understanding and quantitative prediction of the nonlinear morphological transitions of soft bilayer materials hold potential for multifunctional surface regulation.

关键词： hierarchical wrinkle period-doubling period-tripling period-quadrupling fold ridge

Design Optimization of Ocean Thermal Energy Conversion(OTEC)Considering the Off-Design Condition

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Journal of Thermal Science 2023年第6期32卷 2126-2143页

作者： fan Chengcheng CHEN Yongping School of Energy and Environment Southeast UniversityNanjing210096China

The comprehensive optimization of thermodynamic and economic performances is significant for the engineering application of ocean thermal energy conversion(OTEC).Motivated by this,this paper develops a thermo-economic OTEC model and conducts a sensitivity analysis of the OTEC system concerning its thermodynamic and economic ***,the impact of warm-seawater temperature and cold-seawater pumping depth on the net thermal efficiency and the total investment cost are *** results indicate that,an increase in warm-seawater temperature and cold-seawater pumping depth can improve the net thermal efficiency and a higher installed capacity is beneficial to the system *** on these,a design optimization method with considering the on-design and off-design conditions is proposed in this paper,and the dynamic variation of warm-seawater temperature are considered in this *** multi-objective optimization procedure,with the objective functions being the average net thermal efficiency and unit power cost within the operational cycle,the non-dominated sorting genetic algorithm Ⅱ(NSGA-Ⅱ) is employed to maximize the net thermal efficiency and minimize the unit power investment cost,resulting in the Pareto *** net thermal efficiencies of OTEC systems using ammonia and R245fa as working fluids are 4.13% and 3.8%,*** represents an improvement of 19.4% and 57.0%,respectively,compared to traditional optimization methods that do not account for off-design conditions.

关键词： ocean thermal energy conversion sensitivity analysis design optimization off-design scenario approach

Dynamic Scheduling and Path Planning of Automated Guided Vehicles in Automatic Container Terminal

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IEEE/CAA Journal of Automatica Sinica 2022年第11期9卷 2005-2019页

作者： Lijun Yue Houming fan the Department of Transportation Engineering Dalian Maritime UniversityDalian 116026China

The uninterrupted operation of the quay crane(QC)ensures that the large container ship can depart port within laytime,which effectively reduces the handling cost for the container terminal and ship *** QC waiting caused by automated guided vehicles(AGVs)delay in the uncertain environment can be alleviated by dynamic scheduling optimization.A dynamic scheduling process is introduced in this paper to solve the AGV scheduling and path planning problems,in which the scheduling scheme determines the starting and ending nodes of paths,and the choice of paths between nodes affects the scheduling of subsequent *** work proposes a two-stage mixed integer optimization model to minimize the transportation cost of AGVs under the constraint of laytime.A dynamic optimization algorithm,including the improved rule-based heuristic algorithm and the integration of the Dijkstra algorithm and the Q-Learning algorithm,is designed to solve the optimal AGV scheduling and path schemes.A new conflict avoidance strategy based on graph theory is also proposed to reduce the probability of path conflicts between *** experiments are conducted to demonstrate the effectiveness of the proposed model and algorithm over existing methods.

关键词： Automated container terminal dynamic scheduling path planning Q-Learning algorithm rule-based heuristic algorithm