High-speed and high-resolution imaging of surface profiles is critical for the investigation of various structures and mechanical dynamics of micro-and nano-scale devices.In particular,recent emergence of various nonl...High-speed and high-resolution imaging of surface profiles is critical for the investigation of various structures and mechanical dynamics of micro-and nano-scale devices.In particular,recent emergence of various nonlinear,transient and complex mechanical dynamics,such as anharmonic vibrations in mechanical resonators,has necessitated real-time surface deformation imaging with higher axial and lateral resolutions,speed,and dynamic range.However,real-time capturing of fast and complex mechanical dynamics has been challenging,and direct time-domain imaging of displacements and mechanical motions has been a missing element in studying full-field structural and dynamic behaviours.Here,by exploiting the electro-optic sampling with a frequency comb,we demonstrate a line-scan time-of-flight(TOF)camera that can simultaneously measure the TOF changes of more than 1000 spatial coordinates with hundreds megapixels/s pixel-rate and sub-nanometre axial resolution over several millimetres field-of-view.This unique combination of performances enables fast and precise imaging of both complex structures and dynamics in three-dimensional devices and mechanical resonators.展开更多
In this study,a three-dimensional thermo-elastic model that considers the interaction of mechanical and thermal deformation is developed using a semi-analytic method for steady-state rolling contact.Creepage types in ...In this study,a three-dimensional thermo-elastic model that considers the interaction of mechanical and thermal deformation is developed using a semi-analytic method for steady-state rolling contact.Creepage types in all directions are considered in this model.For verification,the numerical analysis results of shear traction and temperature increase are compared separately with existing numerical results,and the consistency is confirmed.The analysis results include heat flux,temperature increase,contact pressure,and shear traction.Under severe rolling conditions,the thermal effect changes the behavior of the contact interface significantly.Furthermore,the effects of creepage,rolling speed,and conformity under different rolling and creep conditions are investigated.展开更多
基金This research was supported by the National Research Foundation of Korea(Grants 2021R1A2B5B03001407 and 2021R1A5A1032937 for J.K,2021R1A4A1031660 for H.Y,2020R1A2C3004885 for J.L.)。
文摘High-speed and high-resolution imaging of surface profiles is critical for the investigation of various structures and mechanical dynamics of micro-and nano-scale devices.In particular,recent emergence of various nonlinear,transient and complex mechanical dynamics,such as anharmonic vibrations in mechanical resonators,has necessitated real-time surface deformation imaging with higher axial and lateral resolutions,speed,and dynamic range.However,real-time capturing of fast and complex mechanical dynamics has been challenging,and direct time-domain imaging of displacements and mechanical motions has been a missing element in studying full-field structural and dynamic behaviours.Here,by exploiting the electro-optic sampling with a frequency comb,we demonstrate a line-scan time-of-flight(TOF)camera that can simultaneously measure the TOF changes of more than 1000 spatial coordinates with hundreds megapixels/s pixel-rate and sub-nanometre axial resolution over several millimetres field-of-view.This unique combination of performances enables fast and precise imaging of both complex structures and dynamics in three-dimensional devices and mechanical resonators.
基金This research was supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology of the Korean government(Grant No.NRF-2019R1A6A3A01097117).
文摘In this study,a three-dimensional thermo-elastic model that considers the interaction of mechanical and thermal deformation is developed using a semi-analytic method for steady-state rolling contact.Creepage types in all directions are considered in this model.For verification,the numerical analysis results of shear traction and temperature increase are compared separately with existing numerical results,and the consistency is confirmed.The analysis results include heat flux,temperature increase,contact pressure,and shear traction.Under severe rolling conditions,the thermal effect changes the behavior of the contact interface significantly.Furthermore,the effects of creepage,rolling speed,and conformity under different rolling and creep conditions are investigated.
