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We describe the optical trapping application of a simple metallic slab optical waveguide structure, and demonstrate the influence of the excited guided modes on the aggregation behavior of silica particles during the irreversible evaporation process. Periodic horizontal stripes are formed by the highly ordered assemblies of the silica spheres, which is explained via the interference effect between the forward propagating modes and its reflection at the solvent surface. Particularly, several layers consisting of high-density particles are discernible in the stripe zones due to the optical binding, while no particles locate between these stripes. Completely different from the self-assembly patterns in the evaporating solvent without excitation of optical modes, this Letter demonstrates the versatility in the possible patterns of the optical assembly by a coupling waveguide with more complex structures.

An inversion model based on neural network combined with genetic algorithm was established to obtain the material parameters of an unknown wedge. Firstly, a back propagation (BP) neural network was introduced and the genetic algorithm was implied to optimize the initial weights and thresholds of the BP neural network. Wedge wave dispersion curves with different angles, density and young’s modulus were obtained by simulation. Then the phase velocity of first-order mode in the anti-symmetrical flexural mode was chosen as the inputs of our inversion model, the corresponding parameters were taken as the outputs. The first-order mode data measured from samples were used to test the validity. It is found that the inversion models can inverse angle, density and young’s modulus simultaneously. Compared with the single BP neural network, it has the advantages of fast convergence speed and high precision.

This research devotes to investigate the propagation characteristics of the guided wave in two layers porous medium - containing structure, and special emphasis is paid on the dependence of the dispersion relation on the porous media parameters. Three models of two-layer cylindrical half-space containing porous medium are established theoretically. The dispersion curves dependence on the cylinder radius and porous medium parameters are analyzed. The results show that the longitudinal guided wave propagation in the structure is dispersive and mainly influenced by the radius of the rod and porosity of the porous media. It suggests that the dispersion curve of L(0,1) shifts to lower frequency with increasing rod radius; The dispersion is mainly influenced by the properties of internal rod, and little change with the porosity for mode 1, whilst the dispersion curves of guided waves gradually shift to low speed with the increasing porosity for mode 2. Particularly, for the model of liquid-immersed porous cylin...

This paper reports on a study of the propagation characteristics of visco-elastic, Rayleigh-like waves in stratified half-space structures. Beginning with the Kelvin model, the characterization equation and the normal displacement of visco-elastic Rayleigh waves in stratified half-space structures are derived and the influence of the visco-elastic modulus on dispersion and attenuation is discussed. Theoretical calculations show that the attenuation-frequency curves perfectly match the phase-frequency curves. The effect of visco-elasticity on the attenuation of the Rayleigh-like wave is larger than its effect on dispersion. For “weak viscosity,” the attenuation is directly proportional to the viscosity modulus and the shear viscosity has a greater impact on the dispersion curves than does the bulk viscosity. The transient response of a visco-elastic Rayleigh wave is also simulated by means of Laplace and Hankel inversion transforms. The results are in good agreement with the theoretic predictions. It is believed the paper’s results and conclusions will provide insights and guidance for estimating visco-elastic parameters and for assessing adhesive quality.

A wireless mouse based on head control is proposed to control the moving direction of computer cursor by sensing the titling direction of user's head. This kind of operational approach make the non-arm disabled using computers realized. The direction induction module is used to sense the tilting of four directions. With the MCU timer, automatic execution of left-click and double- click is available. The MCU of receiver controls the moving and the time to click of the computer cursor. Data transmission of short distance between mouse and receiver is available by using NRF wireless technology, which can make the non-arm disabled control a computer cursor easily. The system provides the disabled a more comfortable way to control the computer. The design has much potential to be applied to lots of occasions.