In this paper, we study the propagation and its failure to propagate (pinning) of a travelling wave in a Nagumo type equation, an equation that describes impulse propagation in nerve axons that also models population ...In this paper, we study the propagation and its failure to propagate (pinning) of a travelling wave in a Nagumo type equation, an equation that describes impulse propagation in nerve axons that also models population growth with Allee effect. An analytical solution is derived for the traveling wave and the work is extended to a discrete formulation with a piecewise linear reaction function. We propose an operator splitting numerical scheme to solve the equation and demonstrate that the wave either propagates or gets pinned based on how the spatial mesh is chosen.展开更多
In this work,a novel friction stir diffusion bonding(FSDB)method was proposed to eliminate hook when joining thin sheets.Three tools,with several convex-vortex pins were innovatively designed to improve the diffusion ...In this work,a novel friction stir diffusion bonding(FSDB)method was proposed to eliminate hook when joining thin sheets.Three tools,with several convex-vortex pins were innovatively designed to improve the diffusion bonding effect of the lap interface.Results showed that sound joints,excellently bonded at the lap interface and without hook,were obtained.The lap interfaces on the joints welded using the T-tool and F-tool almost remained intact,thereby indicating that they were formed by diffusion bonding.The material flow behavior was also simulated by FLUENT software and the results showed that the material flow along thickness was significantly enhanced by increasing the pin number.The joint welded by the T-tool showed shear fracture mode.Sound bonding was formed at the lap interface when using the F-tool and thus the joint showed tensile fracture.展开更多
文摘In this paper, we study the propagation and its failure to propagate (pinning) of a travelling wave in a Nagumo type equation, an equation that describes impulse propagation in nerve axons that also models population growth with Allee effect. An analytical solution is derived for the traveling wave and the work is extended to a discrete formulation with a piecewise linear reaction function. We propose an operator splitting numerical scheme to solve the equation and demonstrate that the wave either propagates or gets pinned based on how the spatial mesh is chosen.
基金supported by the National Natural Science Foundation of China(No.51874201)。
文摘In this work,a novel friction stir diffusion bonding(FSDB)method was proposed to eliminate hook when joining thin sheets.Three tools,with several convex-vortex pins were innovatively designed to improve the diffusion bonding effect of the lap interface.Results showed that sound joints,excellently bonded at the lap interface and without hook,were obtained.The lap interfaces on the joints welded using the T-tool and F-tool almost remained intact,thereby indicating that they were formed by diffusion bonding.The material flow behavior was also simulated by FLUENT software and the results showed that the material flow along thickness was significantly enhanced by increasing the pin number.The joint welded by the T-tool showed shear fracture mode.Sound bonding was formed at the lap interface when using the F-tool and thus the joint showed tensile fracture.