The oxidation behavior of a cast Ni-base superalloy K44 in air at 850-1 000℃for 100 h was studied. The scales on the surface were determined by SEM and EPMA equipped with an EDXS. The results show that oxidation kine...The oxidation behavior of a cast Ni-base superalloy K44 in air at 850-1 000℃for 100 h was studied. The scales on the surface were determined by SEM and EPMA equipped with an EDXS. The results show that oxidation kinetics obey the parabolic law from which the values of activation energy Qp1=221.1 kJ/mol and Qp2=247.6 kJ/mol are estimated. The oxidation scales are composed of loose outer layer of TiO2/TiO-Cr2O3 and a small amount of NiCr2O4 and NiAl2O4, compact intermediate layer Cr2O3, and precipitate of internal oxides Al2O3.展开更多
We study a fourth order curve flow, which is the gradient flow of a functional describing the shapes of human red blood cells. We prove that for any smooth closed initial curve in ?2, the flow has a smooth solution fo...We study a fourth order curve flow, which is the gradient flow of a functional describing the shapes of human red blood cells. We prove that for any smooth closed initial curve in ?2, the flow has a smooth solution for all time and the solution subconverges to a critical point of the functional.展开更多
基金Project(59895152) supported by the National Natural Science Foundation of China
文摘The oxidation behavior of a cast Ni-base superalloy K44 in air at 850-1 000℃for 100 h was studied. The scales on the surface were determined by SEM and EPMA equipped with an EDXS. The results show that oxidation kinetics obey the parabolic law from which the values of activation energy Qp1=221.1 kJ/mol and Qp2=247.6 kJ/mol are estimated. The oxidation scales are composed of loose outer layer of TiO2/TiO-Cr2O3 and a small amount of NiCr2O4 and NiAl2O4, compact intermediate layer Cr2O3, and precipitate of internal oxides Al2O3.
基金supported by Postdoctoral Science Foundation of China, National Natural Science Foundationof China (No. 10631020, 10871061)the Grant for PhD Program of Ministry of Education of China
文摘We study a fourth order curve flow, which is the gradient flow of a functional describing the shapes of human red blood cells. We prove that for any smooth closed initial curve in ?2, the flow has a smooth solution for all time and the solution subconverges to a critical point of the functional.
