Mars is the terrestrial planet in the solar system that is closest to the Earth.Studying the atmospheric parameters of Mars and studying the evolutionary history of the Martian environment on this basis is helpful for...Mars is the terrestrial planet in the solar system that is closest to the Earth.Studying the atmospheric parameters of Mars and studying the evolutionary history of the Martian environment on this basis is helpful for people to discover signs of extraterrestrial life and to study the trend of climate change on Earth.Mie–Rayleigh scattering lidar is an important technology for detecting parameters from the surface to the middle and upper atmosphere.Because of the different aerosol distributions,Mie scattering and Rayleigh scattering have their own optimal detection ranges.Given the long period and high cost of any deep space exploration program,it is important to conduct sufficient feasibility studies and parameter simulations before the payload is launched.In this study,a parameterized lidar mathematical model and Earth’s atmospheric mode are used to compare with the measured signals of ground-based Mie–Rayleigh scattering lidar,and the correctness of the lidar mathematical model is verified.Using the model,we select the landing area of Tianwen-1 and substitute it into the Martian atmospheric mode,and then the Mie–Rayleigh lidar backscattering signal and the key parameters of the lidar system are systematically analyzed under the conditions of a clean Martian atmosphere and a global sandstorm.In addition,the optimal detection altitude ranges of Mie scattering and Rayleigh scattering on Mars under different atmospheric conditions are obtained,which provides a reference for the practical design and development of the subsequent lidar system for the Martian atmospheric environment.展开更多
Transient Rayleigh wave detection is a high-precision nondestructive detection method.At present,it has been widely used in shallow exploration,but rarely used in tunnel lining quality detection.Through the tunnel lin...Transient Rayleigh wave detection is a high-precision nondestructive detection method.At present,it has been widely used in shallow exploration,but rarely used in tunnel lining quality detection.Through the tunnel lining physical model experiment,the layout defects of the double-layer reinforcement lining area were detected and the Rayleigh wave velocity profile and dispersion curve were analyzed after data process-ing,which finally verified the feasibility and accuracy of Rayleigh wave method in detecting the tunnel lining void area.The results show that the method is not affected by the reinforcement inside the lining,the shallow detection is less disturbed and the accuracy is higher,and the data will fluctuate slightly with the deepening of the detection depth.At the same time,this method responds quite accurately to the thickness of the concrete,allowing for the assessment of the tunnel lining’s lack of compactness.This method has high efficiency,good reliability,and simple data processing,and is suitable for nondestructive detection of internal defects of tun-nel lining structure.展开更多
The Laguerre polynomial method has been successfully used to investigate the dynamic responses of a half-space.However,it fails to obtain the correct stress at the interfaces in a layered half-space,especially when th...The Laguerre polynomial method has been successfully used to investigate the dynamic responses of a half-space.However,it fails to obtain the correct stress at the interfaces in a layered half-space,especially when there are significant differences in material properties.Therefore,a coupled Legendre-Laguerre polynomial method with analytical integration is proposed.The Rayleigh waves in a one-dimensional(1D)hexagonal quasicrystal(QC)layered half-space with an imperfect interface are investigated.The correctness is validated by comparison with available results.Its computation efficiency is analyzed.The dispersion curves of the phase velocity,displacement distributions,and stress distributions are illustrated.The effects of the phonon-phason coupling and imperfect interface coefficients on the wave characteristics are investigated.Some novel findings reveal that the proposed method is highly efficient for addressing the Rayleigh waves in a QC layered half-space.It can save over 99%of the computation time.This method can be expanded to investigate waves in various layered half-spaces,including earth-layered media and surface acoustic wave(SAW)devices.展开更多
基金financial support from the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB41030000)the National Natural Science Foundation of China (Grant Nos. 42125402, 42188101, 42304165, and 42374182)+2 种基金the Key-Area Research and Development Program of Guangdong Province (Grant No. 2020B0303020001)the Shanghai Municipal Science and Technology Major Project (Grant No. 2019SHZDZX01)the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0300302)
文摘Mars is the terrestrial planet in the solar system that is closest to the Earth.Studying the atmospheric parameters of Mars and studying the evolutionary history of the Martian environment on this basis is helpful for people to discover signs of extraterrestrial life and to study the trend of climate change on Earth.Mie–Rayleigh scattering lidar is an important technology for detecting parameters from the surface to the middle and upper atmosphere.Because of the different aerosol distributions,Mie scattering and Rayleigh scattering have their own optimal detection ranges.Given the long period and high cost of any deep space exploration program,it is important to conduct sufficient feasibility studies and parameter simulations before the payload is launched.In this study,a parameterized lidar mathematical model and Earth’s atmospheric mode are used to compare with the measured signals of ground-based Mie–Rayleigh scattering lidar,and the correctness of the lidar mathematical model is verified.Using the model,we select the landing area of Tianwen-1 and substitute it into the Martian atmospheric mode,and then the Mie–Rayleigh lidar backscattering signal and the key parameters of the lidar system are systematically analyzed under the conditions of a clean Martian atmosphere and a global sandstorm.In addition,the optimal detection altitude ranges of Mie scattering and Rayleigh scattering on Mars under different atmospheric conditions are obtained,which provides a reference for the practical design and development of the subsequent lidar system for the Martian atmospheric environment.
基金Supported by Project of Natural Science Foundation of Jilin Province(No.20220101172JC).
文摘Transient Rayleigh wave detection is a high-precision nondestructive detection method.At present,it has been widely used in shallow exploration,but rarely used in tunnel lining quality detection.Through the tunnel lining physical model experiment,the layout defects of the double-layer reinforcement lining area were detected and the Rayleigh wave velocity profile and dispersion curve were analyzed after data process-ing,which finally verified the feasibility and accuracy of Rayleigh wave method in detecting the tunnel lining void area.The results show that the method is not affected by the reinforcement inside the lining,the shallow detection is less disturbed and the accuracy is higher,and the data will fluctuate slightly with the deepening of the detection depth.At the same time,this method responds quite accurately to the thickness of the concrete,allowing for the assessment of the tunnel lining’s lack of compactness.This method has high efficiency,good reliability,and simple data processing,and is suitable for nondestructive detection of internal defects of tun-nel lining structure.
基金Project supported by the National Natural Science Foundation of China(No.12102131)the Natural Science Foundation of Henan Province of China(No.242300420248)the International Science and Technology Cooperation Project of Henan Province of China(No.242102521010)。
文摘The Laguerre polynomial method has been successfully used to investigate the dynamic responses of a half-space.However,it fails to obtain the correct stress at the interfaces in a layered half-space,especially when there are significant differences in material properties.Therefore,a coupled Legendre-Laguerre polynomial method with analytical integration is proposed.The Rayleigh waves in a one-dimensional(1D)hexagonal quasicrystal(QC)layered half-space with an imperfect interface are investigated.The correctness is validated by comparison with available results.Its computation efficiency is analyzed.The dispersion curves of the phase velocity,displacement distributions,and stress distributions are illustrated.The effects of the phonon-phason coupling and imperfect interface coefficients on the wave characteristics are investigated.Some novel findings reveal that the proposed method is highly efficient for addressing the Rayleigh waves in a QC layered half-space.It can save over 99%of the computation time.This method can be expanded to investigate waves in various layered half-spaces,including earth-layered media and surface acoustic wave(SAW)devices.
