Magnetic properties and microstructures of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023_)_(7.6) sintered magnets were optimized by sintering treatment. Results show that the knee-point magnetic field, Hknee, is twofold up ...Magnetic properties and microstructures of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023_)_(7.6) sintered magnets were optimized by sintering treatment. Results show that the knee-point magnetic field, Hknee, is twofold up and the intrinsic coercivity Hcjincreases by 40%, ranging from 21.64 to 30.39 kOe at the cost of a little decrease of Brfrom 10.84 to 10.31 kGs with sintering temperature decreasing from 1488 to 1473 K. And the average domain width is narrower and more uniform for the specimen sintered at 1473 K than that of the specimen sintered at 1488 K. It is impressive that the density of lamellar phase increases from ~0.050 to ~0.058 nm^(-1) with the sintering temperature decreasing from 1488 to 1473 K. Moreover, the average cellular size is about ~84 nm for the magnets sintered at 1473 K, which is 80% of that of the magnets sintered at 1488 K(~97 nm). And the cell boundary width of the magnets sintered at 1473 K(~7 nm) is only half average width of the magnets sintered at 1488 K(~14 nm). It is found that the Cu content in the cell boundaries is much higher(~17 at%) in the magnets sintered at 1473 K compared to that of the magnets sintered at 1488 K(~10 at%). It can be concluded that smaller cells and narrower cell boundaries together with higher gradient of Cu content are key points for obtaining the optimum Hkneeand Hcj.展开更多
The influence of mass-flow-rate ratio of inner to outer secondary air on gas-particle flow characteristics was determined in the near-burner region of a centrally fuel-rich swirl coal combustion burner, Velocity and p...The influence of mass-flow-rate ratio of inner to outer secondary air on gas-particle flow characteristics was determined in the near-burner region of a centrally fuel-rich swirl coal combustion burner, Velocity and particle volume flux profiles and normalized particle number concentrations were obtained. Peaks in tangential mean velocity and three-dimensional root-mean-square fluctuation velocities were found to decrease as the mass-flow-rate ratio increased. Moreover, the peaks in the mean axial velocities and parti- cle volume flux near the wall increased, whereas those near the chamber axis decreased. Simultaneously, both recirculation zone and swirl number decreased as the mass-flow-rate ratio increased.展开更多
基金Project supported by the National Key Research and Development Program of China(2016YFB0700903)the National Basic Research Program of China(2014CB643701)+1 种基金the National Natural Science Foundation of China(51331003)Natural Science Foundation of Hebei Province(E2017402039)
文摘Magnetic properties and microstructures of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023_)_(7.6) sintered magnets were optimized by sintering treatment. Results show that the knee-point magnetic field, Hknee, is twofold up and the intrinsic coercivity Hcjincreases by 40%, ranging from 21.64 to 30.39 kOe at the cost of a little decrease of Brfrom 10.84 to 10.31 kGs with sintering temperature decreasing from 1488 to 1473 K. And the average domain width is narrower and more uniform for the specimen sintered at 1473 K than that of the specimen sintered at 1488 K. It is impressive that the density of lamellar phase increases from ~0.050 to ~0.058 nm^(-1) with the sintering temperature decreasing from 1488 to 1473 K. Moreover, the average cellular size is about ~84 nm for the magnets sintered at 1473 K, which is 80% of that of the magnets sintered at 1488 K(~97 nm). And the cell boundary width of the magnets sintered at 1473 K(~7 nm) is only half average width of the magnets sintered at 1488 K(~14 nm). It is found that the Cu content in the cell boundaries is much higher(~17 at%) in the magnets sintered at 1473 K compared to that of the magnets sintered at 1488 K(~10 at%). It can be concluded that smaller cells and narrower cell boundaries together with higher gradient of Cu content are key points for obtaining the optimum Hkneeand Hcj.
基金supported by the Hi-Tech Research and Development Program of China(Contract No.2007AA05Z301)the Key Project of the National Eleventh Five-Year Research Program of China(Contract No.2006BAA01B01)
文摘The influence of mass-flow-rate ratio of inner to outer secondary air on gas-particle flow characteristics was determined in the near-burner region of a centrally fuel-rich swirl coal combustion burner, Velocity and particle volume flux profiles and normalized particle number concentrations were obtained. Peaks in tangential mean velocity and three-dimensional root-mean-square fluctuation velocities were found to decrease as the mass-flow-rate ratio increased. Moreover, the peaks in the mean axial velocities and parti- cle volume flux near the wall increased, whereas those near the chamber axis decreased. Simultaneously, both recirculation zone and swirl number decreased as the mass-flow-rate ratio increased.
