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Thermal buckling and postbuckling of FGM circular plates with in-plane elastic restraints

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Applied Mathematics and Mechanics(English Edition) 2017年第10期38卷 1459-1470页

作者： yun sun Maolin WANG Shirong LI School of Civil Science and Engineering Yangzhou University

Based on von Karman＇s plate theory, the axisymmetric thermal buckling and post-buckling of the functionally graded material （FGM） circular plates with in- plane elastic restraints under transversely non-uniform temperature rise are studied. The properties of the FGM media are varied through the thickness based on a simple power law. The governing equations are numerically solved by a shooting method. The results of the critical buckling temperature, post-buckling equilibrium paths, and configurations for the in-plane elastically restrained plates are presented. The effects of the in-plane elastic restraints, material property gradient, and temperature variation on the responses of thermal buckling and post-buckling are examined in detail.

关键词： functionally graded material (FGM) circular plate in-plane elastic restraint,thermal post-buckling shooting method equilibrium path

Properties and Applications of the Eccentric-gear Drive

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Chinese Journal of Mechanical Engineering 2011年第2期24卷 323-331页

作者： ZHAO yun sun Liang YU Gaohong College of Mechanical Engineering and Automation Zhejiang Sci-Tech UniversiO Hangzhou 310018 China

The eccentric-gear can be used for variable speed ***,due to the vibrations caused by variation of backlash in working process,the eccentric-gear is seldom applied in engineering *** is just a little study about the *** it is necessary to take a further research on eccentric-gear transmission for the applications in the transplanting mechanism of high-speed rice *** key of this paper is to extend understanding of three following characteristics of this drive：（1） The rotation-center-distance and the geometrical-center-distance of the two meshing eccentric gears are respectively the hypotenuse and the straight edge of a right triangle in a cycle.（2） The geometrical center line of two meshing gears divides the linking-line of the two rotational centers equally.（3） When two times the eccentricity of gear,the rotation-center-distance and the geometrical-center-distance form a right triangle,the optimal value of rotation-center-distance can be *** addition,the kinematic analysis,such as the relationship between contact point and midpoint of the linking-line of two gears＇ rotational centers,transmission ratio between the driving-gear and the driven-gear,contact angle and coordinate of contact point are be made,further the formula for calculation of contact force,flow chart for writing optimization program and curve for analysis of data are also be *** relationship between the rotation-center-distance and the geometrical-center-distance,which is determined by three characteristics mentioned above, is a key for the rational design and application of eccentric-gear ***,the presented right triangle property of eccentric gear drive is an important reference for effective analysis of dynamic characteristic of eccentric-gear mechanism and its reliable design.

关键词： eccentric gear transmission property variable speed transmission kinematic and dynamic analysis

Theoretical Study on Reaction Mechanism of Aluminum-Water System

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Chinese Journal of Chemical Physics 2008年第3期21卷 245-249页

作者： yun-lan sun Yan Tian Shu-fen Li Department of Chemical Physics University of Science and Technology of China Hefei 230026 China School of Metallurgy and Resources Anhui University of Technology Maanshan 243002 China

A theoretical study on the reaction of aluminum with water in the gas phase was performed using the hybrid density functional B3LYP and QCISD（T） methods with the 6-311＋G（d,p） and the 6-311＋＋G（d,p） basis sets. The results show that there are three possible reaction pathways that involve four isomers, seven transition structures, and two possible products for the reaction of aluminum with water. The two most favorable reaction pathways were found, whose intermediates and products agreed quite well with experimental results. The enthalpy and Gibbs free energy change of the reaction between A1 and H2O at 298 and 2000 K were calculated. Some results are also in good agreement with the previous calculations or experimental results.

关键词： Aluminum Water Reaction mechanism Hybrid density functional theory

α-LIMIT SETS AND LYAPUNOV FUNCTION FOR MAPS WITH ONE TOPOLOGICAL ATTRACTOR

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Acta Mathematica Scientia 2022年第2期42卷 813-824页

作者： Yiming DING yun sun Center for Mathematical Sciences School of ScienceWuhan University of TechnologyWuhan 430070China

We consider the topological behaviors of continuous maps with one topological attractor on compact metric space *** kind of map is a generalization of maps such as topologically expansive Lorenz map,unimodal map without homtervals and so *** the finiteness and basin conditions,we provide a leveled A-R pair decomposition for such maps,and characterize α-limit set of each *** on weak Morse decomposition of X,we construct a bounded Lyapunov function V(x),which gives a clear description of orbit behavior of each point in X except a meager set.

关键词： Attracting set leveled A-R pair decomposition α-limit set Lyapunov function

Relationship between chloride diffusivity and pore structure of hardened cement paste

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第5期12卷 360-367页

作者： Guo-wen sun Wei sun yun-sheng ZHANG Zhi-yong LIU Jiangsu Key Laboratory of Construction Materials.Southeast University Nanjing 211189china

Based on effective media theory, a predictive model, relating chloride diffusivity to the capillary pores, gel pores, tortuosity factor, and pore size distribution of hardened cement, is proposed. To verify the proposed model, the diffusion coefficient of chloride ions, the degree of hydration, and peak radius of capillary pores of cement paste specimens were measured. The predicted results for chloride diffusivity were compared with published data. The results showed that the predicted chloride diffusivity of hardened cement paste was in good agreement with the experimental results. The effect of the evolution of pore structures in cement paste on chloride diffusivity could be deduced simultaneously using the proposed model.

关键词： Hardened cement paste Chloride diffusivity Porosity Tortuosity factor Constrictivity Key words: Hardened cement paste, Chloride diffusivity, Porosity, Tortuosity factor, Conslrictivity

Variation of singularity of earthquake-size distribution with respect to tectonic regime

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Geoscience Frontiers 2018年第2期9卷 453-458页

作者： Qiu-Ming Cheng Hong-yun sun State Key Lab of Geological Processes and Mineral Resources China University of Geosciences State Key Lab of Geological Processes and Mineral Resources China University of GeosciencesWuhan

Frequency-size relation of earthquakes in a region can be approximated by the Gutenberg-Richter law(GR). This power-law model involves two parameters: a-value measuring seismic activity or earthquake productivity, and b-value describing the relation between frequencies of small and large *** spatial and temporal variations of these two parameters, especially the b-value, have been substantially investigated. For example, it has been shown that b-value depends inversely on differential stress. The b-value has also been utilized as earthquake precursor in large earthquake ***, the physical meaning and properties of b-value including its value range still remain as an open fundamental question. We explore the property of b-value from frequency-size GR model in a new form which relates average energy release and probability of large earthquakes. Based on this new form of GR relation the b-value can be related to the singularity index(1-2/3 b) of fractal energy-probability power-law model. This model as applied to the global database of earthquakes with size M ≥ 5 from 1964 to 2015 indicates a systematic increase of singularity from earthquakes occurring on mid-ocean ridges, to those in subduction zones and in collision zones.

关键词： Fractals Singularity Power-law distribution Plate tectonics Mathematical model Spatial distribution

A gram-scale synthesis of multi-substituted arenes via palladium catalyzed C–H halogenation

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Chinese Chemical Letters 2014年第5期25卷 667-669页

作者： Xiu-yun sun Yong-Hui sun Yu Rao MOE Key Laboratory of Protein Sciences Department of Pharmacology and Pharmaceutical SciencesSchool of Medicine and School of Life SciencesTsinghua University

（6-Amino-2-chloro-3-fluorophenyl）methanol is prepared through both traditional methods and palladium catalyzed iterative C–H halogenation *** comparison to traditional approach,the C–H functionalization strategy demonstrated a few advantages including milder reaction conditions higher yields,better selectivity and practicality,and high chemical diversity.

关键词： Palladium catalysis C–H halogenation Substituted arenes

Thermodynamic Properties of Sodium:A First-Principles Study

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Chinese Physics Letters 2001年第7期18卷 864-867页

作者： WANG Yi sun yun-Feng Department of Physics National Mesoscopic Physics LaboratoryPeking UniversityBeijing 100871 National Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsP.O.Box 8009 Beijing 100088

The Thermal expansion,Hugoniot state and 300 K isotherm of sodium have been calculated on the basis of:(i)the accurate calculations of 0 K total energies with the full-potential linearized augmented plane wave method within the generalized gradient approximation to exchange-correlational functional and(ii)the newly developed classical mean-field statistics where both the cold and thermal parts of the Helmholtz free-energy are entirely derived from the 0 K total energy.A quite satisfactory agreement between calculation and experiment has been *** approach does not invoke any empirical parameter,which has long been a desirability on the field of material science.

关键词： energy. isotherm entirely

A Fusion Based Particle Filter TBD Algorithm for Dim Targets

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Chinese Journal of Electronics 2015年第3期24卷 590-595页

作者： YU Hongbo WANG Guohong CAO Qian sun yun Institute of Information Fusion Naval Aeronautical and Astronautical University Library Naval Aeronautical and Astronautical University

A Fusion based particle filter track-beforedetect algorithm(FPF-TBD) is proposed for dealing with dim targets, in which the importance density function of the Particle filter(PF) is generated by means of a fusion algorithm. In order to construct an accurate approximation to the true proposal distribution, the state at each time scan is predicted according to the Extended Kalman filter algorithm(EKF) and the Unscented Kalman filter(UKF) simultaneously. The information, based on the recursion of the weights, is gathered over multiple scans, and the detection decision is made based on tracking results at the end of the processing chain. By making best use of the recent measurements, this new proposed method can obtain an accurate approximation to the system and as a result, improve the track accuracy and detection performance. Simulation results illustrate the effectiveness of this approach.

关键词： Particle filter Track-before-detect Dim targets Importance density function Fusion algorithm