Effects of strain rate on the microstructure evolution and thermal stability of1050commercial pure aluminum processed by means of split Hopkinson pressure bar(SHPB)and Instron?3369mechanical testing machine were inves...Effects of strain rate on the microstructure evolution and thermal stability of1050commercial pure aluminum processed by means of split Hopkinson pressure bar(SHPB)and Instron?3369mechanical testing machine were investigated.Samples in the deformed state and after various annealing treatments at423?523K(150?250°C)for1h were characterized by TEM and hardness test.The result reveals that the samples in the deformed state were mainly composed of elongated subgrains/cells with high density of dislocations.Microstructures of the quasi-static compressed aluminum were quite stable throughout the temperature range studied,and no significant grain growth was observed.However,for the dynamic impacted one,recrystallized grains with an average grain size of4.7μm were evolved after annealing at523K(250°C)for1h.It is suggested that the annealing behavior of this dynamic deformed aluminum is a continuous process of grain coarsening,rather than the traditional discontinuous recrystallization for the quasi-static compressed aluminum.展开更多
Photo-induced electron transfer versus molecular structure of acceptors is investigated using ultrafast time-resolved transient grating spectroscopy. Typical laser dyes Rhodamine 101 (Rh101) and Rhodamine 6G (Rh6G) in...Photo-induced electron transfer versus molecular structure of acceptors is investigated using ultrafast time-resolved transient grating spectroscopy. Typical laser dyes Rhodamine 101 (Rh101) and Rhodamine 6G (Rh6G) in electron donor solvent-aniline are adopted as the objects. The forward electron transfer time constant from aniline to the excited singlet state of two Rhodamine dyes and subsequent back electron transfer from two dyes to aniline are measured. The experimental results denote that Rh6G presents faster electron transfer rates with aniline in both forward electron transfer and back electron transfer processes. With chemical calculation and qualitative analysis, it is found that the flexible molecular geometry of Rh6G leads to stronger electron coupling with donor solvent and further gives rise to larger electron transfer rates.展开更多
基金Projects(51274245,51574290,U1330126) supported by the National Natural Science Foundation of ChinaProject supported by the Opening Fund of State Key Laboratory of Nonlinear Mechanics,China
文摘Effects of strain rate on the microstructure evolution and thermal stability of1050commercial pure aluminum processed by means of split Hopkinson pressure bar(SHPB)and Instron?3369mechanical testing machine were investigated.Samples in the deformed state and after various annealing treatments at423?523K(150?250°C)for1h were characterized by TEM and hardness test.The result reveals that the samples in the deformed state were mainly composed of elongated subgrains/cells with high density of dislocations.Microstructures of the quasi-static compressed aluminum were quite stable throughout the temperature range studied,and no significant grain growth was observed.However,for the dynamic impacted one,recrystallized grains with an average grain size of4.7μm were evolved after annealing at523K(250°C)for1h.It is suggested that the annealing behavior of this dynamic deformed aluminum is a continuous process of grain coarsening,rather than the traditional discontinuous recrystallization for the quasi-static compressed aluminum.
基金supported by the Science Challenge Project(No.TZ2016001)the National Natural Science Foundation of China(No.21673211)
文摘Photo-induced electron transfer versus molecular structure of acceptors is investigated using ultrafast time-resolved transient grating spectroscopy. Typical laser dyes Rhodamine 101 (Rh101) and Rhodamine 6G (Rh6G) in electron donor solvent-aniline are adopted as the objects. The forward electron transfer time constant from aniline to the excited singlet state of two Rhodamine dyes and subsequent back electron transfer from two dyes to aniline are measured. The experimental results denote that Rh6G presents faster electron transfer rates with aniline in both forward electron transfer and back electron transfer processes. With chemical calculation and qualitative analysis, it is found that the flexible molecular geometry of Rh6G leads to stronger electron coupling with donor solvent and further gives rise to larger electron transfer rates.
