Age-related changes in the viscoelasticity of rabbit lens characterised by surface wave dispersion analysis

2022 ◽  
Vol 52 (1) ◽  
pp. 42-47
Author(s):  
H Zhang ◽  
M Singh ◽  
F Zvietcovich ◽  
K V Larin ◽  
S R Aglyamov
Keyword(s):  
Surface Wave ◽  
Young’S Modulus ◽  
Shear Viscosity ◽  
Young's Modulus ◽  
Viscosity Coefficient ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Optical Coherence ◽  
Surface Wave Dispersion

Abstract The viscoelastic properties of the young and mature rabbit lenses in situ are evaluated using wave-based optical coherence elastography (OCE). Surface waves in the crystalline lens are generated using acoustic radiation force (ARF) focused inside the eyeball. Surface-wave dispersion is measured with a phase-stabilised optical coherence tomography (OCT) system. The Young's modulus and shear viscosity coefficient are quantified based on a Scholte wave model. The results show that both elasticity and viscosity are significantly different between the young and mature lenses. The Young's modulus of the lenses increased with age from 7.74 ± 1.56 kPa (young) to 15.15 ± 4.52 kPa (mature), and the shear viscosity coefficient increased from 0.55 ± 0.04 Pa s (young) and 0.86 ± 0.13 Pa s (mature). It is shown that the combination of ARF excitation, OCE imaging, and dispersion analysis enables nondestructive quantification of lenticular viscoelasticity in situ and shows promise for in vivo applications.

Surface Wave Dispersion Imaging Using Improved τ-p Transform Approach

2013 ◽  
Vol 353-356 ◽  
pp. 1196-1202 ◽  
Author(s):  
Jian Qi Lu ◽  
Shan You Li ◽  
Wei Li
Keyword(s):  
Surface Wave ◽  
Phase Shift ◽  
Dispersion Curve ◽  
Wave Dispersion ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Narrow Frequency Range ◽  
Channel Analysis ◽  
Rayleigh Wave Dispersion

Surface wave dispersion imaging approach is crucial for multi-channel analysis of surface wave (MASW). Because the resolution of inversed S-wave velocity and thickness of a layer are directly subjected to the resolution of imaged dispersion curve. The τ-p transform approach is an efficient and commonly used approach for Rayleigh wave dispersion curve imaging. However, the conventional τ-p transform approach was severely affected by waves amplitude. So, the energy peaks of f-v spectrum were mainly gathered in a narrow frequency range. In order to remedy this shortage, an improved τ-p transform approach was proposed by this paper. Comparison has been made between phase shift and improved τ-p transform approaches using both synthetic and in situ tested data. Result shows that the dispersion image transformed from proposed approach is superior to that either from conventionally τ-p transform or from phase shift approaches.

Crustal structure of northern and southern Tibet from surface wave dispersion analysis

2003 ◽  
Vol 108 (B2) ◽  
Author(s):  
Richard Rapine ◽  
Frederik Tilmann ◽  
Michael West ◽  
James Ni ◽  
Arthur Rodgers
Keyword(s):  
Surface Wave ◽  
Crustal Structure ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Surface Wave Dispersion ◽  
Southern Tibet

scholarly journals Skeletonized inversion of surface wave: Active source versus controlled noise comparison

2016 ◽  
Vol 4 (3) ◽  
pp. SH11-SH19 ◽  
Author(s):  
Jing Li ◽  
Sherif Hanafy
Keyword(s):  
Surface Wave ◽  
Wave Velocity ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Inversion Method ◽  
S Wave ◽  
Surface Wave Dispersion ◽  
Velocity Models ◽  
Western Side ◽  
Geologic Setting

We have developed a skeletonized inversion method that inverts the S-wave velocity distribution from surface-wave dispersion curves. Instead of attempting to fit every wiggle in the surface waves with predicted data, it only inverts the picked dispersion curve, thereby mitigating the problem of getting stuck in a local minimum. We have applied this method to a synthetic model and seismic field data from Qademah fault, located at the western side of Saudi Arabia. For comparison, we have performed dispersion analysis for an active and controlled noise source seismic data that had some receivers in common with the passive array. The active and passive data show good agreement in the dispersive characteristics. Our results demonstrated that skeletonized inversion can obtain reliable 1D and 2D S-wave velocity models for our geologic setting. A limitation is that we need to build layered initial model to calculate the Jacobian matrix, which is time consuming.

An error analysis of frequency-time analysis

1983 ◽  
Vol 73 (1) ◽  
pp. 143-155
Author(s):  
Chi-Chin Feng ◽  
Ta-liang Teng
Keyword(s):  
Surface Wave ◽  
Matched Filter ◽  
Data Extraction ◽  
Wave Dispersion ◽  
Dispersion Analysis ◽  
Time Analysis ◽  
Surface Wave Dispersion ◽  
Period Range ◽  
Dispersion Measurement ◽  
Short Period

abstract The temporal resolution and accuracy of frequency-time analysis (FTAN) as applied to surface-wave dispersion analysis are examined for a period range from 10 to 200 sec. The constant relative bandwidth filter (Dziewonski et al., 1969), optimum bandwidth filter (Inston et al., 1971), and display-equalized filter (Nyman and Landisman, 1977) are carefully examined with respect to their adequacy of application over a broad period range. Among these Gaussian filters, the optimum bandwidth filter gives a better performance for relatively short-period (less than 50 sec) dispersion measurement. To measure surface-wave dispersion for a broad period range, a “matched-filter FTAN” technique is introduced by modifying the “residual dispersion measurement” technique (Dziewonski et al., 1972). A detailed numerical analysis is made on this new technique; the result demonstrates a significant improvement on both the resolution and the accuracy of surface-wave dispersion data extraction over a broad period range up to at least 200 sec.

Improved Surface Wave Dispersion Models, Amplitude Measurements and Azimuth Estimates

2005 ◽  
Author(s):  
Jeffry L. Stevens ◽  
David A. Adams ◽  
G. E. Baker ◽  
Mariana G. Eneva ◽  
Heming Xu
Keyword(s):  
Surface Wave ◽  
Wave Dispersion ◽  
Dispersion Models ◽  
Surface Wave Dispersion
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