传统电磁式扭矩传感器通过电磁感应测量轴两端扭转角度实现测量扭矩的作用,为此本文建立适合的线圈结构模型,针对传统单线圈结构感应电动势微弱的现象,分析影响磁场聚焦参数,对激励线圈结构进行优化设计。通过Ansys Maxwell仿真分析,得...传统电磁式扭矩传感器通过电磁感应测量轴两端扭转角度实现测量扭矩的作用,为此本文建立适合的线圈结构模型,针对传统单线圈结构感应电动势微弱的现象,分析影响磁场聚焦参数,对激励线圈结构进行优化设计。通过Ansys Maxwell仿真分析,得到不同组线圈磁场强度竖直分量的三维磁场云图,利用算法优化得到最佳导磁体结构,改进线圈结构得出最佳线圈结构模型。通过对仿真结果分析,得到改进后的线圈是传统单线圈结构磁场强度的26.9倍,与理论推导值近似一致,磁场能量峰值集中在2.4 mm 2左右的区域上。作用在该磁场中的接收线圈随轴转动时,感应电动势是传统单线圈结构的17.63倍,呈现与旋转周期相同的周期变化,效果得到明显改善。展开更多
A concave two-dimensional （2D） photonic crystal waveguide （PCW） with corrugated surface is theoret- ically used as a focusing structure. To design this structure, a genetic algorithm is combined with the finite-di...A concave two-dimensional （2D） photonic crystal waveguide （PCW） with corrugated surface is theoret- ically used as a focusing structure. To design this structure, a genetic algorithm is combined with the finite-difference time-domain method. For PCWs with different degrees of concaveness, the power reaches about 80% at different focusing points when the morphology of the concave surface is optimized. More importantly, the focusing location is easily controlled by changing the location of the detector placed in the outout field.展开更多
Symmetric tapered dielectric structures in metal have demonstrated applications such as the nanofocusing of surface plasmon polaritons, as well as the waveguiding of V-channel polaritons. Yet the fabrication of smooth...Symmetric tapered dielectric structures in metal have demonstrated applications such as the nanofocusing of surface plasmon polaritons, as well as the waveguiding of V-channel polaritons. Yet the fabrication of smooth-surfaced tapered structure remains an obstacle to most researchers. We have successfully developed a handy method to fabricate metal-sandwiched tapered nanostructures simply with electron beam lithography. Though these structures are slightly different from conventional symmetric V-shaped structures, systematic simulations show that similar functionality of surface plasmon polariton nanofocusing can still be achieved. When parameters are properly selected, wavelength- selective nanofocusing of surface plasmon polaritons can be obtained.展开更多
Superconducting linear accelerators(SCL)have a high acceleration gradient and are capable of operating in a high-duty factor mode.For high-power and high-intensity SCL,the design of beam dynamics generally follows the...Superconducting linear accelerators(SCL)have a high acceleration gradient and are capable of operating in a high-duty factor mode.For high-power and high-intensity SCL,the design of beam dynamics generally follows the principle that the zero-current periodic phase advance(σ0)of each degree of freedom is less than 90°to avoid envelope instability caused by space charge.However,this principle is obtained under the condition of a completely periodic focusing channel,and it is ambiguous for pseudoperiodic structures,such as linear accelerators.Although transverse beam dynamics without acceleration have been studied by other researchers,it appears that there are some connections between pure 2D and 3D beam dynamics.Based on these two points,five focusing schemes for the solenoid and quadrupole doublet channels were designed to simulate the beam behavior with non-constantσ0.Among them,the four schemes follow the characteristics of variation in the zero-current longitudinal phase advance(σ0l)under a constant acceleration gradient and synchronous phase.The zero-current transverse phase advance(σ0t)is consistent withσ0l,based on the equipartition requirement.The initialσ0twas set to 120°,110°,100°,and 90°,and was then gradually decreased to approximately 40°at the end of the channel.The last scheme maintains the maximumσ0tof88°by reducing the acceleration gradient of the corresponding cavities,until the point at whichσ0tequals88°with a normal gradient.Using the stopbands obtained from the linearized envelope equations and multiparticle particle-in-cell(PIC)simulations,the transport properties of both continuous and 3D-bunched beams with the acceleration of the five focusing schemes were studied.It was found that for a CW beam,when tune depression>0.7,σ0tcan break through 90°when the beams were transported in both solenoid and quadrupole doublet periodic focusing channels.When tune depression<0.7,the conclusions were different.For the solenoid focusing system,σ0tcan partially break through 90°,and the b展开更多
文摘传统电磁式扭矩传感器通过电磁感应测量轴两端扭转角度实现测量扭矩的作用,为此本文建立适合的线圈结构模型,针对传统单线圈结构感应电动势微弱的现象,分析影响磁场聚焦参数,对激励线圈结构进行优化设计。通过Ansys Maxwell仿真分析,得到不同组线圈磁场强度竖直分量的三维磁场云图,利用算法优化得到最佳导磁体结构,改进线圈结构得出最佳线圈结构模型。通过对仿真结果分析,得到改进后的线圈是传统单线圈结构磁场强度的26.9倍,与理论推导值近似一致,磁场能量峰值集中在2.4 mm 2左右的区域上。作用在该磁场中的接收线圈随轴转动时,感应电动势是传统单线圈结构的17.63倍,呈现与旋转周期相同的周期变化,效果得到明显改善。
基金supported by research funding fromthe Nanjing University of Science and Technology (Nos.2010ZYTS059 and AE88030)the Natural Science Foundation of Jiangsu Province (No.BK2010483)
文摘A concave two-dimensional （2D） photonic crystal waveguide （PCW） with corrugated surface is theoret- ically used as a focusing structure. To design this structure, a genetic algorithm is combined with the finite-difference time-domain method. For PCWs with different degrees of concaveness, the power reaches about 80% at different focusing points when the morphology of the concave surface is optimized. More importantly, the focusing location is easily controlled by changing the location of the detector placed in the outout field.
基金Project supported by the National Natural Science Foundation of China (Grant Nos 90606023, 10574003 and 20731160012)a National 973 Project (Grant No 2007CB936202 and 2009CB623703)MOST from China's Ministry of Science and Technology and Hong Kong's NSFC/RGC Joint Research Scheme (Project No N HKUST615/06)
文摘Symmetric tapered dielectric structures in metal have demonstrated applications such as the nanofocusing of surface plasmon polaritons, as well as the waveguiding of V-channel polaritons. Yet the fabrication of smooth-surfaced tapered structure remains an obstacle to most researchers. We have successfully developed a handy method to fabricate metal-sandwiched tapered nanostructures simply with electron beam lithography. Though these structures are slightly different from conventional symmetric V-shaped structures, systematic simulations show that similar functionality of surface plasmon polariton nanofocusing can still be achieved. When parameters are properly selected, wavelength- selective nanofocusing of surface plasmon polaritons can be obtained.
基金the National Natural Science Foundation of China(Nos.11375122 and 11875197).
文摘Superconducting linear accelerators(SCL)have a high acceleration gradient and are capable of operating in a high-duty factor mode.For high-power and high-intensity SCL,the design of beam dynamics generally follows the principle that the zero-current periodic phase advance(σ0)of each degree of freedom is less than 90°to avoid envelope instability caused by space charge.However,this principle is obtained under the condition of a completely periodic focusing channel,and it is ambiguous for pseudoperiodic structures,such as linear accelerators.Although transverse beam dynamics without acceleration have been studied by other researchers,it appears that there are some connections between pure 2D and 3D beam dynamics.Based on these two points,five focusing schemes for the solenoid and quadrupole doublet channels were designed to simulate the beam behavior with non-constantσ0.Among them,the four schemes follow the characteristics of variation in the zero-current longitudinal phase advance(σ0l)under a constant acceleration gradient and synchronous phase.The zero-current transverse phase advance(σ0t)is consistent withσ0l,based on the equipartition requirement.The initialσ0twas set to 120°,110°,100°,and 90°,and was then gradually decreased to approximately 40°at the end of the channel.The last scheme maintains the maximumσ0tof88°by reducing the acceleration gradient of the corresponding cavities,until the point at whichσ0tequals88°with a normal gradient.Using the stopbands obtained from the linearized envelope equations and multiparticle particle-in-cell(PIC)simulations,the transport properties of both continuous and 3D-bunched beams with the acceleration of the five focusing schemes were studied.It was found that for a CW beam,when tune depression>0.7,σ0tcan break through 90°when the beams were transported in both solenoid and quadrupole doublet periodic focusing channels.When tune depression<0.7,the conclusions were different.For the solenoid focusing system,σ0tcan partially break through 90°,and the b
