The intelligent optimization of a multi-objective evolutionary algorithm is combined with a gradient algorithm. The hybrid multi-objective gradient algorithm is framed by the real number. Test functions are used to an...The intelligent optimization of a multi-objective evolutionary algorithm is combined with a gradient algorithm. The hybrid multi-objective gradient algorithm is framed by the real number. Test functions are used to analyze the efficiency of the algorithm. In the simulation case of the water phantom, the algorithm is applied to an inverse planning process of intensity modulated radiation treatment （IMRT）. The objective functions of planning target volume （PTV） and normal tissue （NT） are based on the average dose distribution. The obtained intensity profile shows that the hybrid multi-objective gradient algorithm saves the computational time and has good accuracy, thus meeting the requirements of practical applications.展开更多
This paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow discharged from a convergent-divergent nozzle.The noise phenomenon of flow is generated by an emission of 't...This paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow discharged from a convergent-divergent nozzle.The noise phenomenon of flow is generated by an emission of 'transonic tones'.The results obtained show that the frequency of a transonic tone,that differs from the frequency of a screech tone due to the shock-cell structures in a jet and originates in the shock wave in the nozzle,increases in proportion to the nozzle pressure ratio.The high-order transonic tone has the directivity in the direction of the flow.As for the transonic tone's frequency,the separated zone was calculated by using a simple flow model considering the propagating perturbation.The results of the model corresponded to the results of this experiment well.展开更多
基金Supported by the National Basic Research Program of China ("973" Program)the National Natural Science Foundation of China (60872112, 10805012)+1 种基金the Natural Science Foundation of Zhejiang Province(Z207588)the College Science Research Project of Anhui Province (KJ2008B268)~~
文摘The intelligent optimization of a multi-objective evolutionary algorithm is combined with a gradient algorithm. The hybrid multi-objective gradient algorithm is framed by the real number. Test functions are used to analyze the efficiency of the algorithm. In the simulation case of the water phantom, the algorithm is applied to an inverse planning process of intensity modulated radiation treatment （IMRT）. The objective functions of planning target volume （PTV） and normal tissue （NT） are based on the average dose distribution. The obtained intensity profile shows that the hybrid multi-objective gradient algorithm saves the computational time and has good accuracy, thus meeting the requirements of practical applications.
文摘This paper describes experimental and numerical works to investigate noise phenomenon in supersonic flow discharged from a convergent-divergent nozzle.The noise phenomenon of flow is generated by an emission of 'transonic tones'.The results obtained show that the frequency of a transonic tone,that differs from the frequency of a screech tone due to the shock-cell structures in a jet and originates in the shock wave in the nozzle,increases in proportion to the nozzle pressure ratio.The high-order transonic tone has the directivity in the direction of the flow.As for the transonic tone's frequency,the separated zone was calculated by using a simple flow model considering the propagating perturbation.The results of the model corresponded to the results of this experiment well.
