The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform

Du Xiu-feng - One of the best experts on this subject based on the ideXlab platform.

  • Qualitative Analysis of Predator-Prey Model with Holling III and Harvesting Rate
    Journal of Harbin University of Science and Technology, 2020
    Co-Authors: Du Xiu-feng
    Abstract:

    In this paper,a predator-prey model with Holling Ⅲ functional response and linear harvesting rate is researched,in which the prey is under density restriction.The paper discusses the properties of every equilibrium under different conditions.By drawing the Path Curve,analyzing the directions of the Curve and,the global equilibrium is verified.At the same time,by constructing Dulac function,the condition of surrounding of equilibrium without close Path Curve is obtained.The boundness of solutions and the sufficient conditions of positive equilibrium which is global are discussed.By using numerical simulation,it analyzes the influence of harvesting rate to the stability of equilibrium.

  • Stability Analysis of a Ratio-Dependent Functional Response Predator-Prey Model
    Mathematics in Practice and Theory, 2020
    Co-Authors: Du Xiu-feng
    Abstract:

    In this paper,a ratio-dependent functional response predator-prey model is researched, the model of qualitative and stable analysis are discussed.The existential condition of unique positive equilibrium and properties of every equilibrium are also discussed.Particularly, the sufficient conditions of globally asymptotic stability of every equilibrium are obtained.By drawing the Path Curve and analyzing the directions of the Curve,the paper gets the condition of globally asymptotic stability of origin.And it proves the condition that the model has no nontrivial positive periodic solution.At the same time,by constructing Lyapunov function,the globally asymptotic stability of the unique positive equilibrium point is obtained.

Yi-sheng Zhang - One of the best experts on this subject based on the ideXlab platform.

  • Compound process of selective laser processed alumina parts densified by cold isostatic pressing and solid state sintering: Experiments, full process simulation and parameter optimization
    Ceramics International, 2015
    Co-Authors: Zijian Wang, Wenting He, Yusheng Shi, Kai Liu, Yi-sheng Zhang
    Abstract:

    Combined cold isostatic pressing (CIP) of alumina selective laser processed (SLP) parts and solid state sintering (SSS) were used to obtain complex shaped and relatively dense alumina ceramic components. Simulation of the compound process was fulfilled, and the simulative results were found to agree well with the experimental ones. A link was built between the microstructure evolution and the macroscopic deformation by implanting the sintering Path Curve into the constitutive model. The relative density distribution and its standard deviation were defined to evaluate the homogeneity of the parts. The effects of structural and process parameters on the densification and deformation during the compound process were studied using experimental and simulation methods. Laser energy density, ratio of the fillet radius to the bag thickness and the sintering acceleration during the selective laser processing, cold isostatic pressing, and solid state sintering, were defined to optimize the whole process.

L.m. Zhao - One of the best experts on this subject based on the ideXlab platform.

  • ICDMA - Computer Simulation Technology of Lapping Process for Polycrystalline Diamond
    2012 Third International Conference on Digital Manufacturing & Automation, 2012
    Co-Authors: Q.j. Zhang, J.y. Li, H. Wang, X.q. Yang, L.m. Zhao
    Abstract:

    To raise the polishing efficiency of polycrystalline diamond (PCD) superhard material, crank rocker arm mechanism has been developed by using computer simulation technology. On the basis of kinematics and geometry principle, the mathematical model for the crank rocker arm mechanism was established. The movement Path and the instantaneous speed of the workpiece center point on the crank rocker arm were derived. The computer dynamic simulation software was developed and the Path Curve and instantaneous speed have been figured. Before the crank rocker arm mechanism was applied in the machining process, the effect of the length of varies arms on the Path Curve and the instantaneous speed has been researched. The optimal parameters combinations which can fulfill the application requirement were found. The optimal mechanism has been applied in the polishing process of polycrystalline diamond. The polishing efficiency is one and a half times higher than conventional method. The application of computer simulation software provides a simple and effective method for designing or optimizing the machine.

  • Computer Simulation Technology of Lapping Process for Polycrystalline Diamond
    2012 Third International Conference on Digital Manufacturing & Automation, 2012
    Co-Authors: Q.j. Zhang, J.y. Li, H. Wang, X.q. Yang, L.m. Zhao
    Abstract:

    To raise the polishing efficiency of polycrystalline diamond (PCD) superhard material, crank rocker arm mechanism has been developed by using computer simulation technology. On the basis of kinematics and geometry principle, the mathematical model for the crank rocker arm mechanism was established. The movement Path and the instantaneous speed of the workpiece center point on the crank rocker arm were derived. The computer dynamic simulation software was developed and the Path Curve and instantaneous speed have been figured. Before the crank rocker arm mechanism was applied in the machining process, the effect of the length of varies arms on the Path Curve and the instantaneous speed has been researched. The optimal parameters combinations which can fulfill the application requirement were found. The optimal mechanism has been applied in the polishing process of polycrystalline diamond. The polishing efficiency is one and a half times higher than conventional method. The application of computer simulation software provides a simple and effective method for designing or optimizing the machine.

Zijian Wang - One of the best experts on this subject based on the ideXlab platform.

  • Compound process of selective laser processed alumina parts densified by cold isostatic pressing and solid state sintering: Experiments, full process simulation and parameter optimization
    Ceramics International, 2015
    Co-Authors: Zijian Wang, Wenting He, Yusheng Shi, Kai Liu, Yi-sheng Zhang
    Abstract:

    Combined cold isostatic pressing (CIP) of alumina selective laser processed (SLP) parts and solid state sintering (SSS) were used to obtain complex shaped and relatively dense alumina ceramic components. Simulation of the compound process was fulfilled, and the simulative results were found to agree well with the experimental ones. A link was built between the microstructure evolution and the macroscopic deformation by implanting the sintering Path Curve into the constitutive model. The relative density distribution and its standard deviation were defined to evaluate the homogeneity of the parts. The effects of structural and process parameters on the densification and deformation during the compound process were studied using experimental and simulation methods. Laser energy density, ratio of the fillet radius to the bag thickness and the sintering acceleration during the selective laser processing, cold isostatic pressing, and solid state sintering, were defined to optimize the whole process.

Meipeng Zhong - One of the best experts on this subject based on the ideXlab platform.

  • kinematics and trajectory of both sides cylindrical lapping process in planetary motion type
    International Journal of Machine Tools & Manufacture, 2015
    Co-Authors: Ju Long Yuan, Zhixiang Chen, Ping Zhao, Meipeng Zhong
    Abstract:

    Abstract The both-sides lapping process in planetary motion type is proposed in this paper to lap and polish the cylindrical surface of bearing roller. The rolling speed of roller is the key kinematical parameter that affects the generation of cylindrical surface of roller. Through analysis of friction forces and pure rolling motion, it was discovered that the rolling speed of roller only depends on the rotation speed of lower plate rather than upper plate. Based on the above result, the geometry and kinematics of workpiece in this method is described, and the functions are proved valid by an experiment in which the rolling speed of roller is observed in video. By theoretical tests under different speed conditions, it is indicated that the roller's rolling speed varies with respect to time along a nonstandard cosine Curve with an offset, its amplitude depends on the speeds of lower plate rotation and carrier circulation, and its offset depends on the speeds of lower plate rotation and carrier rotation. Based on geometry and kinematics, the trajectories on the cylindrical surface of roller and on the flat surface of plate are both described and simulated. The standard deviation and the range of Path Curve length distribution density are applied to numerically evaluate and analyze the trajectory distribution. The effect of speed parameters on the trajectory distribution, and the generation of trajectory with respect to time are investigated.