Antenna array is one of the methods which can generate Orbital Angular Momentum(OAM)waves.However,OAM waves generated by different antenna arrays have different characteristics of Electric-field(E-field)com-ponents...Antenna array is one of the methods which can generate Orbital Angular Momentum(OAM)waves.However,OAM waves generated by different antenna arrays have different characteristics of Electric-field(E-field)com-ponents'distribution and radiation patterns.In order to solve this problem,we derive E-feld formulas of OAM waves generated by different kinds of dipole antenna array in this paper.The dipole antenna arrays are arranged by three methods:1)antenna elements are in the same direction of y axis,2)antenna elements are in the radial direction and 3)antenna elements are in the azimuthal direction.Results show that x components,y components and z components carry different OAM modes under the three conditions.Simulation results show that the same direction antenna array produces the best OAM waves because the y component is dominated by OAM mode l and RHCP/LHCP waves are negligible in energy,while the pure OAM waves carried by the z components generated by the other two antenna arrays have little energy.In addition,only the radiation pattern ofl=0 produced by the same direction antenna array does not have a null zone in the propagation direction.Radiation patterns of l=±1 do not have null zones in the propagation direction generated by other two antenna arrays.展开更多
High machining precision and machining efficiency can be obtained in grinding WC-Co coating by cup wheel. The conventional model of the grinding force is not suitable for the grinding of the cup wheel due to the diffe...High machining precision and machining efficiency can be obtained in grinding WC-Co coating by cup wheel. The conventional model of the grinding force is not suitable for the grinding of the cup wheel due to the difference in grinding style between the cup wheel and the conventional external wheel. So the grit grinding process of the cup wheel is studied, and a new concept of the effective grinding width of the cup wheel is presented. Then the grinding force in grinding WC-Co coating materials by cup wheel is analyzed and a theoretical formula is deduced. Finally, experimental results of the grinding force verify the correctness and the precision of the theoretical formula.展开更多
基金This study was supported by the National Natural Science Foundation of China(NSFC 61771213)Shanghai Aerospace Science and Technology Innovation Fund(SAST2017-113)the Fundamental Research Funds for the Central Universities(HUST2016JCTD203,2018KFYYXJJ140).
文摘Antenna array is one of the methods which can generate Orbital Angular Momentum(OAM)waves.However,OAM waves generated by different antenna arrays have different characteristics of Electric-field(E-field)com-ponents'distribution and radiation patterns.In order to solve this problem,we derive E-feld formulas of OAM waves generated by different kinds of dipole antenna array in this paper.The dipole antenna arrays are arranged by three methods:1)antenna elements are in the same direction of y axis,2)antenna elements are in the radial direction and 3)antenna elements are in the azimuthal direction.Results show that x components,y components and z components carry different OAM modes under the three conditions.Simulation results show that the same direction antenna array produces the best OAM waves because the y component is dominated by OAM mode l and RHCP/LHCP waves are negligible in energy,while the pure OAM waves carried by the z components generated by the other two antenna arrays have little energy.In addition,only the radiation pattern ofl=0 produced by the same direction antenna array does not have a null zone in the propagation direction.Radiation patterns of l=±1 do not have null zones in the propagation direction generated by other two antenna arrays.
文摘High machining precision and machining efficiency can be obtained in grinding WC-Co coating by cup wheel. The conventional model of the grinding force is not suitable for the grinding of the cup wheel due to the difference in grinding style between the cup wheel and the conventional external wheel. So the grit grinding process of the cup wheel is studied, and a new concept of the effective grinding width of the cup wheel is presented. Then the grinding force in grinding WC-Co coating materials by cup wheel is analyzed and a theoretical formula is deduced. Finally, experimental results of the grinding force verify the correctness and the precision of the theoretical formula.
