Observation of discrete gap solitons in one-dimensional waveguide arrays with alternating spacings and saturable defocusing nonlinearity

We consider, both experimentally and theoretically, the existence and stability of localized, symmetric, and antisymmetric gap solitons (GSs) in binary lattices of identical waveguides but with alternating spacings. Furthermore, the properties of surface GSs at the boundary of the lattice are explored.     

Square‐Wave Voltammetry: A Review on the Recent Progress

A review on the recent progress of square‐wave voltammetry is presented, covering the period of the last five years. The review addresses the new theoretical development of the technique as well as its application for mechanistic purposes, electrode kinetic measurements, biochemical and analytical applications. Besides, a few novel methodological modifications are proposed that might expand the scope and application of the technique.     

The virial theorem and ground state energy estimates of nonlinear Schrödinger equations in $$\mathbb {R}^2$$ with square root and saturable nonlinearities in nonlinear optics

The virial theorem is a nice property for the linear Schrödinger equation in atomic and molecular physics as it gives an elegant ratio between the kinetic and potential energies and is useful in assessing the quality of numerically computed eigenvalues. If the governing equation is a nonlinear Schrödinger equation with power-law nonlinearity, then a similar ratio can be obtained but there seems to be no way of getting any eigenvalue estimates. It is surprising as far as we are concerned that when the nonlinearity is either square-root or saturable nonlinearity (not a power-law), one can develop a virial theorem and eigenvalue estimates of nonlinear Schrödinger (NLS) equations in \({{\mathbb {R}}^{2}}\) with square-root and saturable nonlinearity, respectively. Furthermore, we show here that the eigenvalue estimates can be used to obtain the 2nd order term (which is of order \(\ln \Gamma \)) of the lower bound of the ground state energy as the coefficient \(\Gamma \) of the nonlinear term tends to infinity.     

Staircase cyclic voltammetry of electrocatalytic reaction inhibited by the product

A model of electrocatalytic reaction influenced by the potential dependent inhibition is developed. The response of investigated mechanism is anomalous voltammogram consisting of two anodic peaks. The relationship between two peak currents and the parameters of electrode reaction was analysed theoretically.

     

On different aspects of the optical rogue waves nature

Rogue waves are giant nonlinear waves that suddenly appear and disappear in oceans and optics. We discuss the facts and fictions related to their strange nature, dynamic generation, ingrained instability, and potential applications. We present rogue wave solutions to the standard cubic nonlinear Schrödinger equation that models many propagation phenomena in nonlinear optics. We propose the method of mode pruning for suppressing the modulation instability of rogue waves. We demonstrate how to produce stable Talbot carpets—recurrent images of light and plasma waves—by rogue waves, for possible use in nanolithography. We point to instances when rogue waves appear as numerical artefacts, due to an inadequate numerical treatment of modulation instability and homoclinic chaos of rogue waves. Finally, we display how statistical analysis based on different numerical procedures can lead to misleading conclusions on the nature of rogue waves.

     

稀土元素对植物体内细胞分裂素的影响

本文采用生物鉴定法(bioassay)和高效液相色谱法(HPLE)测定施用稀土元素的作物,从植物内源激素的角度来讨论稀土元素对植物的生理作用影响,测定结果表明:施用稀土元素后,细胞分裂素(Cyto-kinin CTC)平均增长25％左右,说明稀土元素促进了细胞分裂、诱导芽的形成。     

Theory of irreversible electrode reactions coupled to ion transfer across the liquid/liquid interface

Kinetically controlled electro-oxidation of a redox probe dissolved in the organic solvent, which is interposed between an electrode surface and an aqueous solution as a thin layer, is analyzed theoretically. It is demonstrated that the electrode reaction rate constant can be measured by the variation of scan rate in linear scan voltammetry both in the absence and in the superfluity of the supporting electrolyte dissolved in the film.Dedicated to Professor Dr. Alan M. Bond on the occasion of his 60th birthday     

Influence of anion-induced adsorption on D.C. polarography of metal ions

Some adsorption isotherms for anion-induced adsorption of metal ions are proposed. The influences of adsorption on d.c polarograms are examined theoretically. The consequences for the determination of stability constants from polarographic data are discussed.     

Goos-Hänchen shift and time delay in dispersive nonlinear media

We present an analysis of the influence of the Goos-Hänchen effect on tunneling times, group delay and dwell time, of electromagnetic waves propagating through an obstacle made of left-handed metamaterial embedded in a dielectric which exhibits saturable type of nonlinearity. The derived equations show that only the group delay, is affected by the Goos-Hänchen shift without any impact on the dwell time. Besides the reduction of the group delay, the most remarkable result is the possibility for total reduction of the Goos-Hänchen shift for finite incident angles. These phenomena are observable in the frequency region for which metamaterial exhibits negative index of refraction.