The software AnyCasting was used to simulate the thixotropic die-casting process of semi-solid Al-Cu-Mn-Ti alloy slurry to form the parts of a particular shape, especially on how the in-gate size of die and injection ...The software AnyCasting was used to simulate the thixotropic die-casting process of semi-solid Al-Cu-Mn-Ti alloy slurry to form the parts of a particular shape, especially on how the in-gate size of die and injection speed affect the process. The results showed that the die cavity can be filled well with the semi-solid slurry in form of laminar flow under conditions that the temperature of the semi-solid slurry is 640℃ and that of die 200-240℃, thickness of in-gate is 11 mm and, more important, the injection speed should be changed from 0.1 to 1.0 m/s when 60% of die cavity has been filled. The simulation result is highly proved in conformity to the actual die-casting specimens in accordance to the filling process as simulated. Moreover, the hardness of the specimens is up to 116.6 HV after the treatment of solid solution plus underaging, i.e. 45.7% higher than that in conventional ones.展开更多
In this paper, several preimage entropies for semi-flows on compact metric spaces are introduced and studied. We prove that most of these entropies are invariant in a certain sense under conjugacy when the semi-flows ...In this paper, several preimage entropies for semi-flows on compact metric spaces are introduced and studied. We prove that most of these entropies are invariant in a certain sense under conjugacy when the semi-flows under consideration are free of fixed points. The relation between these entropies is studied and an inequality relating them is given. It is also shown that most of these entropies for semi-flow are consistent with that for the time-1 mapping.展开更多
基金the National Natural Science Foundation of China （No. 50374031）the Natural Science Foundation of Liaoning Province （No. 20054003） the Postdoctoral Science Poundation of China （No. 2005038591）.
文摘The software AnyCasting was used to simulate the thixotropic die-casting process of semi-solid Al-Cu-Mn-Ti alloy slurry to form the parts of a particular shape, especially on how the in-gate size of die and injection speed affect the process. The results showed that the die cavity can be filled well with the semi-solid slurry in form of laminar flow under conditions that the temperature of the semi-solid slurry is 640℃ and that of die 200-240℃, thickness of in-gate is 11 mm and, more important, the injection speed should be changed from 0.1 to 1.0 m/s when 60% of die cavity has been filled. The simulation result is highly proved in conformity to the actual die-casting specimens in accordance to the filling process as simulated. Moreover, the hardness of the specimens is up to 116.6 HV after the treatment of solid solution plus underaging, i.e. 45.7% higher than that in conventional ones.
基金the Tianyuan-Mathematics Foundation of China(10426012)the Doctoral Foundation of Hebei Normal University(L2005B02).
文摘In this paper, several preimage entropies for semi-flows on compact metric spaces are introduced and studied. We prove that most of these entropies are invariant in a certain sense under conjugacy when the semi-flows under consideration are free of fixed points. The relation between these entropies is studied and an inequality relating them is given. It is also shown that most of these entropies for semi-flow are consistent with that for the time-1 mapping.
