It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of pre...It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.展开更多
We study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-onedimensional Bose-Einstein condensate by including an imaginary three-body recombination loss term and an imaginary li...We study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-onedimensional Bose-Einstein condensate by including an imaginary three-body recombination loss term and an imaginary linear feeding one in the Gross Pitaevskii equation, trapped in a shallow optical-lattice potential. Based on the direct approach of perturbation theory for the nonlinear Schroedinger equation, we demonstrate that the height （as well as width） of bright soliton may have little change through selecting experimental parameters.展开更多
Exogenous electrical stimulation plays an important role on endothelial cells and vessels. Study on the effect of electrical stimulation on endothelial cells might be helpful to regulate cell metabolism on a certain e...Exogenous electrical stimulation plays an important role on endothelial cells and vessels. Study on the effect of electrical stimulation on endothelial cells might be helpful to regulate cell metabolism on a certain extent, or provide new ideas for vascular tissue engineering. A bioreactor that can apply electrical stimulation was designed on the basis of parallel-plate chamber. To investigate the possible effect of electrical stimulation on human umbilical vein endothelial cells （HUVECs）, the different levels and duration＇s electrical stimulations were applied to HUVECs in culture. The cell morphology was observed by microscopy and the levels of endothelial nitric oxide synthase （eNOS） gene were measured by RT-PCR. Different levels and durations of electrical stimulation produce different effects on eNOS gene expression. The eNOS gene expressions of the experimental group ceils under the voltage of 50 mV, 100 mV, 150 mV and 200 mV were significantly lower than that of the control group after 3-hour electrical stimulation, while the eNOS gene levels of the experimental group cells in 6-hour electrical stimulation were higher than those of the control group under all tested voltages. After 12-hour stimulation, the eNOS gene levels of HUVECs decreased under 50 mV, and then gradually increased until 200 inV. The low voltage of 6-hour electrical stimulation is more appropriate for HUVECs growth.展开更多
基金Project(51305334)supported by the National Natural Science Foundation of ChinaProject(51335009)supported by the National Natural Science Foundation of China for Key Program+1 种基金Project(CXY1442(4))supported by the Science and Technology Planning Project of Xi’an,ChinaProject supported by Shaanxi Province Postdoctoral Science Research Program of China
文摘It is necessary to use the integrated stainless steel pipe having two fitting bodies without welds while train travelling at high speed. In order to form this type of integrated stainless steel pipe, the method of preforming combined finish forming process is developed. The preforming process is characterized by flaring combined upsetting for left fitting body which is like a flange, and is characterized by tube axial compressive process under die constraint for right fitting body which is like a double-wall pipe. The finite element simulations of the processes are carried out by software package DEFORM, and the results indicate that: 1) left or right fitting body can be formed by a two-step forming process without folding and under-filling defects; 2) by using two-step forming, strain and stress in left fitting body are larger than those in right fitting body, and deformation in right fitting body is more homogenous than the deformation in left fitting body; 3) two or more preforming steps may be needed for left fitting body considering the distributions of strain and stress.
基金Supported by National Natural Science Foundation of China under Grant Nos.10775049 and 10375022the Natural Science Foundation of Hunan Province under Grant No.09JJ6008the Education Ministry of Hunan Province under Grant No.09C637
文摘We study the formation of a dynamically-stabilized dissipation-managed bright soliton in a quasi-onedimensional Bose-Einstein condensate by including an imaginary three-body recombination loss term and an imaginary linear feeding one in the Gross Pitaevskii equation, trapped in a shallow optical-lattice potential. Based on the direct approach of perturbation theory for the nonlinear Schroedinger equation, we demonstrate that the height （as well as width） of bright soliton may have little change through selecting experimental parameters.
文摘Exogenous electrical stimulation plays an important role on endothelial cells and vessels. Study on the effect of electrical stimulation on endothelial cells might be helpful to regulate cell metabolism on a certain extent, or provide new ideas for vascular tissue engineering. A bioreactor that can apply electrical stimulation was designed on the basis of parallel-plate chamber. To investigate the possible effect of electrical stimulation on human umbilical vein endothelial cells （HUVECs）, the different levels and duration＇s electrical stimulations were applied to HUVECs in culture. The cell morphology was observed by microscopy and the levels of endothelial nitric oxide synthase （eNOS） gene were measured by RT-PCR. Different levels and durations of electrical stimulation produce different effects on eNOS gene expression. The eNOS gene expressions of the experimental group ceils under the voltage of 50 mV, 100 mV, 150 mV and 200 mV were significantly lower than that of the control group after 3-hour electrical stimulation, while the eNOS gene levels of the experimental group cells in 6-hour electrical stimulation were higher than those of the control group under all tested voltages. After 12-hour stimulation, the eNOS gene levels of HUVECs decreased under 50 mV, and then gradually increased until 200 inV. The low voltage of 6-hour electrical stimulation is more appropriate for HUVECs growth.
