This paper presents an explicit difference scheme with accuracy and branching stability for solving onedimensional parabolic type equation by the method of undetermined parameters and its truncation error is O(△t4+△...This paper presents an explicit difference scheme with accuracy and branching stability for solving onedimensional parabolic type equation by the method of undetermined parameters and its truncation error is O(△t4+△x4). The stability condition is r=a△t/△x2<1/2.展开更多
The hot deformation behaviors of 35%SiCp/2024 aluminum alloy composites were studied by hot compression tests using Gleeble-1500D thermo-mechanical simulator at temperatures ranging from 350 to 500 °C under strai...The hot deformation behaviors of 35%SiCp/2024 aluminum alloy composites were studied by hot compression tests using Gleeble-1500D thermo-mechanical simulator at temperatures ranging from 350 to 500 °C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 225.4 kJ/mol. To demonstrate the potential workability, the stable zones and the instability zones in the processing map were identified and verified through micrographs. Considering processing map and microstructure, the hot deformation should be carried out at the temperature of 500 °C and the strain rate of 0.1-1 s-1.展开更多
Now the image display techniques have made great progress. The planar display and a fully new true 3-D volumetric display technique are rapidly researched and come into the application. A method based on the voxel mak...Now the image display techniques have made great progress. The planar display and a fully new true 3-D volumetric display technique are rapidly researched and come into the application. A method based on the voxel makes the observer able to get a true 3-D effect freely without any additional facilities. This paper introduces the basic form of the swept-volume display technique and discusses its voxelization process. By the translational motion prototype, this paper emphasizes how to get the voxel mapping matrix. The translated image data are the data of the beam source deflections. Finally the voxel ordering and the optimizing are also discussed.展开更多
A family of high_order accuracy explicit difference schemes for solving 2_dimension parabolic P.D.E. are constructed. Th e stability condition is r=Δt/Δx 2=Δt/Δy 2【1/2 and the truncation err or is O(Δt 3+Δx...A family of high_order accuracy explicit difference schemes for solving 2_dimension parabolic P.D.E. are constructed. Th e stability condition is r=Δt/Δx 2=Δt/Δy 2【1/2 and the truncation err or is O(Δt 3+Δx 4).展开更多
Influence of thermomechanical processing on the microstructure, texture evolution and mechanical properties of A1-Mg-Si-Cu alloy sheets was studied systematically. The quite weak mechanical properties anisotropy was o...Influence of thermomechanical processing on the microstructure, texture evolution and mechanical properties of A1-Mg-Si-Cu alloy sheets was studied systematically. The quite weak mechanical properties anisotropy was obtained in the alloy sheet through thermomechanical processing optimizing. The highly elongated microstmcture is the main structure for the hot or cold-rolled alloy sheets. H {001 } （110） and E { 111 } （110） are the main texture components in the surface layer of hot-rolled sheet, while ]/-fibre is dominant in quarter and center layers. Compared with the hot-rolled sheet, the intensities offl-fibre components are higher after the first cold rolling, but H {001 }（110） component in the surface layer decreases greatly. Almost no deformation texatre can be observed after intermediate annealing. And fl-fibre becomes the main texture again after the final cold rolling. With the reduction of the thickness, the through-thickness texture gradients become much weaker. The through-thickness recrystallization texture in the solution treated sample only has cubeyD {001 }（310） component. The relationship among thermomechanical processing, microstructure, texture and mechanical orouerties was analyzed.展开更多
文摘This paper presents an explicit difference scheme with accuracy and branching stability for solving onedimensional parabolic type equation by the method of undetermined parameters and its truncation error is O(△t4+△x4). The stability condition is r=a△t/△x2<1/2.
基金Project(51371077)supported by the National Natural Science Foundation of China
文摘The hot deformation behaviors of 35%SiCp/2024 aluminum alloy composites were studied by hot compression tests using Gleeble-1500D thermo-mechanical simulator at temperatures ranging from 350 to 500 °C under strain rates of 0.01-10 s-1. The true stress-true strain curves were obtained in the tests. Constitutive equation and processing map were established. The results show that the flow stress decreases with the increase of deformation temperature at a constant strain rate, and increases with the increase of strain rate at constant temperature, indicating that composite is a positive strain rate sensitive material. The flow stress behavior of composite during hot compression deformation can be represented by a Zener-Hollomon parameter in the hyperbolic sine form. Its activation energy for hot deformation Q is 225.4 kJ/mol. To demonstrate the potential workability, the stable zones and the instability zones in the processing map were identified and verified through micrographs. Considering processing map and microstructure, the hot deformation should be carried out at the temperature of 500 °C and the strain rate of 0.1-1 s-1.
文摘Now the image display techniques have made great progress. The planar display and a fully new true 3-D volumetric display technique are rapidly researched and come into the application. A method based on the voxel makes the observer able to get a true 3-D effect freely without any additional facilities. This paper introduces the basic form of the swept-volume display technique and discusses its voxelization process. By the translational motion prototype, this paper emphasizes how to get the voxel mapping matrix. The translated image data are the data of the beam source deflections. Finally the voxel ordering and the optimizing are also discussed.
文摘A family of high_order accuracy explicit difference schemes for solving 2_dimension parabolic P.D.E. are constructed. Th e stability condition is r=Δt/Δx 2=Δt/Δy 2【1/2 and the truncation err or is O(Δt 3+Δx 4).
基金Project(2013AA032403) supported by the National High-Tech Research and Development Program of ChinaProject(YETP0409) supported by the Beijing Higher Education Young Elite Teacher Project in 2013,ChinaProject(51301016) supported by the National Natural Science Foundation of China
文摘Influence of thermomechanical processing on the microstructure, texture evolution and mechanical properties of A1-Mg-Si-Cu alloy sheets was studied systematically. The quite weak mechanical properties anisotropy was obtained in the alloy sheet through thermomechanical processing optimizing. The highly elongated microstmcture is the main structure for the hot or cold-rolled alloy sheets. H {001 } （110） and E { 111 } （110） are the main texture components in the surface layer of hot-rolled sheet, while ]/-fibre is dominant in quarter and center layers. Compared with the hot-rolled sheet, the intensities offl-fibre components are higher after the first cold rolling, but H {001 }（110） component in the surface layer decreases greatly. Almost no deformation texatre can be observed after intermediate annealing. And fl-fibre becomes the main texture again after the final cold rolling. With the reduction of the thickness, the through-thickness texture gradients become much weaker. The through-thickness recrystallization texture in the solution treated sample only has cubeyD {001 }（310） component. The relationship among thermomechanical processing, microstructure, texture and mechanical orouerties was analyzed.
