A heat-resistant dispersion-strengthening nano-Al_2O_3/Cu composite with highstrength and high electric conductivity was fabricated in a multiplex medium. The internaloxidation product, microstructures and properties ...A heat-resistant dispersion-strengthening nano-Al_2O_3/Cu composite with highstrength and high electric conductivity was fabricated in a multiplex medium. The internaloxidation product, microstructures and properties of the composite, and the process flow weresystematically studied. It is confirmed that this new technique simplifies the process and improvesthe properties of the composite. X-ray analysis indicates that the alumina particles formed duringinternal oxidation consist of a large mount of gamma-Al_2O_3 and a certain amount of theta-Al_2O_3and alpha-Al_2O_3. TEM observation shows that the obtained gamma-Al_2O_3 nano-particles areuniformly distributed in the copper grains; their mean size and space between particles are 7 runand 30 nm, respectively. The main properties of the composite with 50 percent cold deformation areas follows: the electric conductivity is 51 MS/m (87 percent IACS), sigma_b = 628 MPa, and thehardness is HRB86. After annealing at 1273 K, all or most of the above properties remain, and themicrostructures are still dependent on elongated fiber-form grains.展开更多
On the hypothesis that telomerase reverse transcriptase (TERT) of cardiac myocytes (CMs) is consistent with cell cycle distribution as well as tumour cells, we plan to investigate the expression of TERT in CMs and how...On the hypothesis that telomerase reverse transcriptase (TERT) of cardiac myocytes (CMs) is consistent with cell cycle distribution as well as tumour cells, we plan to investigate the expression of TERT in CMs and how TERT is in keeping with CMs cycle distribution after birth and under hypoxia, and roughly understand how hypoxia affects activity of TERT promoter.展开更多
文摘A heat-resistant dispersion-strengthening nano-Al_2O_3/Cu composite with highstrength and high electric conductivity was fabricated in a multiplex medium. The internaloxidation product, microstructures and properties of the composite, and the process flow weresystematically studied. It is confirmed that this new technique simplifies the process and improvesthe properties of the composite. X-ray analysis indicates that the alumina particles formed duringinternal oxidation consist of a large mount of gamma-Al_2O_3 and a certain amount of theta-Al_2O_3and alpha-Al_2O_3. TEM observation shows that the obtained gamma-Al_2O_3 nano-particles areuniformly distributed in the copper grains; their mean size and space between particles are 7 runand 30 nm, respectively. The main properties of the composite with 50 percent cold deformation areas follows: the electric conductivity is 51 MS/m (87 percent IACS), sigma_b = 628 MPa, and thehardness is HRB86. After annealing at 1273 K, all or most of the above properties remain, and themicrostructures are still dependent on elongated fiber-form grains.
文摘On the hypothesis that telomerase reverse transcriptase (TERT) of cardiac myocytes (CMs) is consistent with cell cycle distribution as well as tumour cells, we plan to investigate the expression of TERT in CMs and how TERT is in keeping with CMs cycle distribution after birth and under hypoxia, and roughly understand how hypoxia affects activity of TERT promoter.
