Abstract: A method produces tantalum powder. The method includes: (1) uniformly mixing a tantalum powder raw material, metal magnesium and at least one alkali metal and/or alkaline earth metal halide, loading the mixture into a container, and putting the container in a furnace; (2) raising the temperature of the furnace to 600-1200° C. in the presence of inert gas, and soaking; (3) at the end of soaking, lowering the temperature of the furnace to 600-800° C., vacuumizing the interior of the furnace to 10 Pa or less, soaking under the negative pressure so that the excessive metal is separated; (4) thereafter, raising the temperature of the furnace to 750-1200° C. in the presence of inert gas, and soaking so that the tantalum powder is sintered in the molten salt after oxygen reduction; (5) then cooling to room temperature and passivating to obtain a mixed material containing halide and tantalum powder; and (6) separating the tantalum powder from the resulting mixture.

Abstract: A motor includes a bus bar assembly including a resin holder and a wire integrally provided in the resin holder. The wire is connected to an external power supply and a coil leading-out wire of the motor, the resin holder is provided with a positioning hole penetrating in an axial direction, and at least a portion of the wire is exposed from the positioning hole. The wire is integrally provided in the resin holder simply through the positioning hole, and thus the resulting bus bar assembly is low in cost and light in weight.

Abstract: A positioning method using height-constraint-based extended Kalman filter, suitable for a GNSS navigation and positioning system, comprises: obtaining an estimated state value of a current epoch by using an extended Kalman filter algorithm and according to an estimated state value of a previous epoch; constraining a positioning height of the current epoch by establishing a height constraint condition, so as to obtain an optimum estimated value of the current epoch and a corresponding mean square error, wherein the optimum estimated value satisfies the height constraint condition; further correcting the estimated state value by using a pseudorange obtained from the mean square error and a measured Doppler shift residual to obtain a final estimated state value of the current epoch, thus more accurately obtaining positioning information of a target to be positioned in the current epoch and enhancing the accuracy of GNSS navigation and positioning.

Abstract: A positioning method using height-constraint-based extended Kalman filter, suitable for a GNSS navigation and positioning system, comprises: obtaining an estimated state value of a current epoch by using an extended Kalman filter algorithm and according to an estimated state value of a previous epoch; constraining a positioning height of the current epoch by establishing a height constraint condition, so as to obtain an optimum estimated value of the current epoch and a corresponding mean square error, wherein the optimum estimated value satisfies the height constraint condition; further correcting the estimated state value by using a pseudorange obtained from the mean square error and a measured. Doppler shift residual to obtain a final estimated state value of the current epoch, thus more accurately obtaining positioning information of a target to be positioned in the current epoch and enhancing the accuracy of GNSS navigation and positioning.