We study the travelling wave solutions for a system of coupled KdV equations derived by Lou et al [11]. In that paper, they found 5 types of Painlevé integrable systems for the coupled KdV system. We show that each of them can be reduced to a partially or completely uncoupled system, through which the dynamical behavior of travelling wave solutions can be determined. In some parameter regions, ...

We propose a model for transport of solutes in a porous medium participating in a dissolu-tion/precipitation reaction, in general not in equilibrium. For an unbounded spatial domain, travelling wave solutions exist, if and only if the charge distribution is constant and we deal with a dissolution situation. The travelling wave in fact exhibits a sharp dissolution front. The wave is given in a n...

This paper is devoted to the travelling wave analysis of the Euler-Poisson model for a plasma consisting of electrons and ions. When the Debye length tends to 0, this system leads to a nonlinear hyperbolic system in a nonconservative form called quasineutral Euler system. Our aim is to determine the admissible jump relations and shock solutions for the quasineutral Euler system as limits of tra...

We show data from a working 45-stage analog VLSI cochlea, built on a 2.2” x 2.2“ tiny chip. The novel architectural features in this cochlea are: 1. The use of a wide-linear-range low-noise subthreshold transconductance amplifier, 2. The use of “fuse-like” nonlinear positive-feedback amplification in the second-order cochlear fJter. Several new circuit techniques used in the design are describe...

Wave mixing inside optical resonators, while experiencing a large enhancement of the nonlinear interaction efficiency, suffers from strong bandwidth constraints, preventing its practical exploitation for processing broad-band signals. Here we show that such limits are overcome by the new concept of travelling-wave resonant four-wave mixing (FWM). This approach combines the efficiency enhancemen...

The study of travelling waves or fronts has become an essential part of the mathematical analysis of nonlinear diffusion-convection-reaction processes. Whether or not a nonlinear second-order scalar reaction-convection-diffusion equation admits a travelling-wave solution can be determined by the study of a singular nonlinear integral equation. This article is devoted to demonstrating how this c...

Travelling waves are the physical basis of frequency discrimination in many vertebrate and invertebrate taxa, including mammals, birds, and some insects. In bushcrickets (Tettigoniidae), the crista acustica is the hearing organ that has been shown to use sound-induced travelling waves. Up to now, data on mechanical characteristics of sound-induced travelling waves were only available along the ...

We investigate the spectrum of the linear operator coming from the sine-Gordon equation linearized about a travelling kink-wave solution. Using various geometric techniques as well as some elementary methods from ODE theory, we find that the point spectrum of such an operator is purely imaginary provided the wave speed c of the travelling wave is not ±1. We then compute the essential spectrum o...