The effects of homogenization parameters on the microstructure evolution and tensile behavior of a balanced Al−Mg−Si alloy were investigated using the optical microscope,scanning electron microscope,X-ray diffraction,...The effects of homogenization parameters on the microstructure evolution and tensile behavior of a balanced Al−Mg−Si alloy were investigated using the optical microscope,scanning electron microscope,X-ray diffraction,electron probe microanalyzer,differential scanning calorimetry,electrical conductivity test,and tensile test.The results show that Mg_(2)Si andβ-AlFeSi are the main intermetallic compounds in the as-cast structure,and Mg solute microsegregation is predominant inside the dendrite cell.The prediction of the full dissolution time of Mg_(2)Si by a kinetic model is consistent with the experiment.Theβ-AlFeSi in the alloy exhibits high thermal stability and mainly undergoes dissolution and coarsening during homogenization at 560℃,and only a small portion is converted toα-AlFeSi.The optimal homogenization parameters are determined as 560℃and 360 min,when considering the evolution of microstructure and resource savings.Both the strength and ductility of the alloy increased after homogenization.展开更多
An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the ...An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the population are also studied. We find that the effect of the maximum recovery per unit of time and the recruitment rate of the popula- tion over some level are two factors which lead to the backward bifurcation, and in some cases, the model may undergo the saddle-node bifurcation or Bogdanov-Takens bifurca- tion. It is shown that the disease-free equilibrium is globally asymptotically stable under some conditions, Numerical simulations are consistent with our obtained results in the- orems, which show that improving the efficiency and capacity of treatment is important for control of disease.展开更多
基金financially supported by State Grid Corporation of China (No.5500-202128250A-0-0-00)。
文摘The effects of homogenization parameters on the microstructure evolution and tensile behavior of a balanced Al−Mg−Si alloy were investigated using the optical microscope,scanning electron microscope,X-ray diffraction,electron probe microanalyzer,differential scanning calorimetry,electrical conductivity test,and tensile test.The results show that Mg_(2)Si andβ-AlFeSi are the main intermetallic compounds in the as-cast structure,and Mg solute microsegregation is predominant inside the dendrite cell.The prediction of the full dissolution time of Mg_(2)Si by a kinetic model is consistent with the experiment.Theβ-AlFeSi in the alloy exhibits high thermal stability and mainly undergoes dissolution and coarsening during homogenization at 560℃,and only a small portion is converted toα-AlFeSi.The optimal homogenization parameters are determined as 560℃and 360 min,when considering the evolution of microstructure and resource savings.Both the strength and ductility of the alloy increased after homogenization.
文摘An SIS epidemic model with the standard incidence rate and saturated treatment func- tion is proposed. The dynamics of the system are discussed, and the effect of the capacity for treatment and the recruitment of the population are also studied. We find that the effect of the maximum recovery per unit of time and the recruitment rate of the popula- tion over some level are two factors which lead to the backward bifurcation, and in some cases, the model may undergo the saddle-node bifurcation or Bogdanov-Takens bifurca- tion. It is shown that the disease-free equilibrium is globally asymptotically stable under some conditions, Numerical simulations are consistent with our obtained results in the- orems, which show that improving the efficiency and capacity of treatment is important for control of disease.
