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This paper constructs three types of bioprosthetic valve leaflets’ parametric model via computer aided design, a series of accurate parameters of the bioproshtetic heart valve, such as radius of the sutural ring, height of the supporting stent and inclination of the supporting stent, are determined. Numerical simulation is used to determine the effect of different shape designs on the mechanical performance of the bioprosthetic valve leaflet. The dynamic behavior of the valve during diastolic phase is analyzed. The finite element analysis results show the stress distribution of the ellipsoidal and spherical valve leaflets are comparatively reasonable. The ellipsoidal and spherical valve leaflets have the following advantages over the cylindrical leaflet valve, lower peak von-Mises stress, smaller stress concentration area, and relatively uniform stress distribution. The ellipsoidal and spherical valve leaflets may contribute to the long term durability of the valve. This work is very helpful to manufacture valvular leaflets with reasonable shapes and to prolong the lifetime of the bioprosthetic heart valve.

We address the existence of surface solitons at an interface in a defocusing cubic medium with an imprinted one-dimensional (1D) composite Bessel optical lattice. This setting is composed of two Bessel lattices with different orders and different modulation depths, separated beside both sides of an interface. Stability analysis and numerical propagation simulations prove that solitons supported by the model are dynamically stable in the entire domain of their existence. The order of lattice determines the shape of soliton, and the amplitude of soliton depends on the lattice modulation depth. The experimental realization of the scheme is also proposed. Our results may provide another effective way of controlling the shapes of surface solitons and thus their evolutions by introducing a new freedom degree.

Dynamics of (1+1)D spatial solitons in a Kerr medium with a transversely symmetrical refractive index profile is investigated. Propagation of solitons is analysed theoretically by using an effective-particle approach. Analytical results show that the soliton oscillates periodically with a variable acceleration. The expression of oscillatory period is derived by introducing a concept of 'average acceleration'. Both acceleration and oscillatory period are determined by the parameters of the input soliton and the waveguide. Propagations of solitons are simulated numerically and good agreement is obtained between the theoretical and numerical results.

Two-dimensional vector vortex solitons in harmonic optical lattices are investigated. The stability properties of such solitons are closely connected to the lattice depth V0. For small V0, vector vortex solitons with the total zero-angular momentum are more stable than those with the total nonzero-angular momentum, while for large V0, this case is inversed. If V0 is large enough, both the types of such solitons are stable.

We investigate the existence and stability of different families of spatial solitons in optical waveguide arrays whose amplitudes obey a disordered distribution. The competition between focusing nonlinearity and linearly disordered refractive index modulation results in the formation of spatial localized nonlinear states. Solitons originating from Anderson modes with few nodes are robust during propagation. While multi-peaked solitons with in-phase neighboring components are completely unstable, multipole-mode solitons whose neighboring components are out-of-phase can propagate stably in wide parameter regions provided that their power exceeds a critical value. Our findings, thus, provide the first example of stable higher-order nonlinear states in disordered systems.

We address the existence, stability and propagation dynamics of solitons supported by large-scale defects surrounded by the harmonic photonic lattices imprinted in the defocusing saturable nonlinear medium. Several families of soliton solutions, including ∞at-topped, dipole-like, and multipole-like solitons, can be supported by the defected lattices with difierent heights of defects. The width of existence domain of solitons is determined solely by the saturable parameter. The existence domains of various types of solitons can be shifted by the variations of defect size, lattice depth and soliton order. Solitons in the model are stable in a wide parameter window, provided that the propagation constant exceeds a critical value, which is in sharp contrast to the case where the soliton trains is supported by periodic lattices imprinted in defocusing saturable nonlinear medium. We also flnd stable solitons in the semi-inflnite gap which rarely occur in the defocusing media.

We elucidate the existence, stability and propagation dynamics of multi-spot soliton packets in focusing saturable media. Such solitons are supported by an interface beside which two harmonically photonic lattices with different modulation depths are imprinted. We show that the surface model can support stable higher-order structures in the form of asymmetrical surface soliton trains, which is in sharp contrast to homogeneous media or uniform harmonic lattice modulations where stable asymmetrical multi-peaked solitons do not exist. Surface trains can be viewed as higher-order soliton states bound together by several different lowest order solitons with appropriate relative phases. Their existence as stable objects enriches the concept of compact manipulation of several different solitons as a single entity and offers additional freedom to control the shape of solitons by adjusting the modulation depths beside the interface.

We demonstrate that a new class of stable composite soliton exists in a two-dimensional lattice. It can be produced by the evolution of a stationary solution of nonlinear Schrdinger equation with a periodic potential modulation. We emphasize that this new kind of composite soliton is different from the dipole soliton reported before though they seem alike. The components of the soliton exchange energy during the propagations and the total energy of soliton conserves.

The interaction between two optical vortices in a linear medium is investigated numerically. An instability resembling the symmetrybreaking instability occurs when the vortices carry opposite topological charges. The screw dislocations wi ll evolve into another type of dislocationedge dislocation with the propagatin g of optical field. The sum of the topological charges conserves in the whole pr ocess.