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Analytical study of the reflection and transmission coefficient of the submarine interface

Zhang G., Hao C., Yao C.

Acta Geophysica

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2018

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Vol. 66, no. 4

449--460

EN

The analytical study of the reflection and transmission coefficient of the seafloor interface is essential for the characterization of the ocean bottom in marine seismic exploration. Based on the boundary conditions of the seafloor interface, the analytical expression of the reflection and transmission coefficient at the submarine interface is derived in this study by using the steady-state wave solution of the elastic wave in a homogeneous, isotropic medium. With this analytical expression, the characteristics of the reflection and transmission coefficient at the submarine interface are analysed and discussed using critical angles. The results show that the change in the reflection and transmission coefficient with the incidence angle presents a ‘‘segmented’’ characteristic, in which the critical angle is the dividing point. The amplitude value and phase angle of the coefficient at the submarine interface change dramatically at the critical angle, which is related to the P- and S-wave velocities in the seabed layer. Compared with the stiff seabed, the soft seabed has a larger P-wave critical angle and an absence of the converted S-wave critical angle, owing to the low P- and S-wave velocities in the solid seabed layer. By analysing and discussing the special changes that occur in the coefficient values at the critical angle, the reflection and transmission characteristics of the different incident angles are obtained. Synthetic models of both stiff and soft seafloors are provided in this study to verify the analytical results. Finally, we compared our synthetic results with real data from the Gulf of Mexico, which enabled the validation of our conclusions.

2

Surface plasmon resonance sensor based on photonic crystal fiber filled with silver nanowires

Fu X., Lu Y., Huang X., Hao C., Wu B., Yao J.

Optica Applicata

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2011

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Vol. 41, nr 4

941--951

EN

Silver nanowire filled photonic crystal fibers are proposed in this paper to achieve surface plasmon resonance sensors and overcome the complicacy and difficulty of coating the holes in the photonic crystal fiber. Optical field distributions of these fibers at different wavelengths are calculated and simulated using the finite element method (FEM), and the sensing properties are discussed in both areas of resonant wavelength and intensity detection. Numerical simulation results show that carefully designed structure of the sensor brings about an excellent effect, with both spectral and intensity sensitivity in the range of 4×10-5-5×10-5 RIU, better than in the case of similar structures coated with metal film, and the fabrication is expected to be simplified.

3

On some local and global geometry of Orlicz sequence spaces endowed with the Orlicz norm

Hao C., Li Y., Wang T.

Annales Societatis Mathematicae Polonae. Seria 1: Commentationes Mathematicae

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2000

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[Z] 40

69-91

EN

A critetion of URWC point in Orlicz sequence spaces endowed with the Orlicz norm is given. As a corollary, we get a criterion in order that a space has LURWC property.