We theoretically investigate the effect of symmetry breaking on the ultrafast plasmon responses of Au nanodisk(ND)dimers by varying the diameter of one of the constituent nanodisks.In the case of a single ultrafast la...We theoretically investigate the effect of symmetry breaking on the ultrafast plasmon responses of Au nanodisk(ND)dimers by varying the diameter of one of the constituent nanodisks.In the case of a single ultrafast laser pulse,we demonstrate that the ultrafast responses of Au ND homodimer can be significantly modified due to the effect of symmetry breaking.The symmetric dimer shows a single broad spectral peak,whereas the size-asymmetric dimer shows three spectral peaks.The first system displays at most one temporal maximum and no beats in ultrafast temporal,whereas the second system may have three temporal maxima and two beats due to a combination of broken symmetry and the coherent superposition between various plasmon modes induced by the ultra-short laser pulse.Moreover,the shape of temporal dynamics of the size-asymmetric dimer is significantly deformed due to the excitation of local plasmon modes with different wavelength components.Furthermore,the decay time of the amplitude of the local field is longer and oscillates with a high frequency due to the narrower linewidth and red-shifted spectral peaks.We show that the ultrafast plasmon responses of both dimers can be controlled by varying the relative phase and time delays between a pair of two pulses.Our results will open new paths to understanding ultrafast plasmon responses in asymmetric heterodimers with suitable properties for different applications.展开更多
Until now,seismic-isolation structures have not yet been applied in the railway field.The reason is that though a seismic-isolation structure can reduce the inertial force to the structure,the energy absorption causes...Until now,seismic-isolation structures have not yet been applied in the railway field.The reason is that though a seismic-isolation structure can reduce the inertial force to the structure,the energy absorption causes big response displacement on the structure,which adversely effects the running safety of the trains supported by the structure.In this paper,a methodology for seismic running safety assessment is introduced,and a new type of seismic-isolation foundation is proposed,which can convert the seismic response displacement in the lateral direction of track to the longitudinal direction that has a less adverse effect on the running safety of the train.The isolation foundation is composed of FPS(Friction Pendulum System)slider,concave plate and guide ditch.Moreover,through model experiments and 3D numerical simulation,it is verified that the proposed foundation can keep both the effects of the seismic isolation and the running safety of the train during an earthquake.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.91850109 and 61775021)“111”Project of China(Grant No.D17017)Key Laboratory of Ultrafast and Extreme Ultraviolet Optics of Jilin Province,and Ministry of Education Key Laboratory for Cross-Scale Micro and Nano Manufacturing,Changchun University of Science and Technology。
文摘We theoretically investigate the effect of symmetry breaking on the ultrafast plasmon responses of Au nanodisk(ND)dimers by varying the diameter of one of the constituent nanodisks.In the case of a single ultrafast laser pulse,we demonstrate that the ultrafast responses of Au ND homodimer can be significantly modified due to the effect of symmetry breaking.The symmetric dimer shows a single broad spectral peak,whereas the size-asymmetric dimer shows three spectral peaks.The first system displays at most one temporal maximum and no beats in ultrafast temporal,whereas the second system may have three temporal maxima and two beats due to a combination of broken symmetry and the coherent superposition between various plasmon modes induced by the ultra-short laser pulse.Moreover,the shape of temporal dynamics of the size-asymmetric dimer is significantly deformed due to the excitation of local plasmon modes with different wavelength components.Furthermore,the decay time of the amplitude of the local field is longer and oscillates with a high frequency due to the narrower linewidth and red-shifted spectral peaks.We show that the ultrafast plasmon responses of both dimers can be controlled by varying the relative phase and time delays between a pair of two pulses.Our results will open new paths to understanding ultrafast plasmon responses in asymmetric heterodimers with suitable properties for different applications.
文摘Until now,seismic-isolation structures have not yet been applied in the railway field.The reason is that though a seismic-isolation structure can reduce the inertial force to the structure,the energy absorption causes big response displacement on the structure,which adversely effects the running safety of the trains supported by the structure.In this paper,a methodology for seismic running safety assessment is introduced,and a new type of seismic-isolation foundation is proposed,which can convert the seismic response displacement in the lateral direction of track to the longitudinal direction that has a less adverse effect on the running safety of the train.The isolation foundation is composed of FPS(Friction Pendulum System)slider,concave plate and guide ditch.Moreover,through model experiments and 3D numerical simulation,it is verified that the proposed foundation can keep both the effects of the seismic isolation and the running safety of the train during an earthquake.
