Double Integrable Couplings and Their Constructing Method

To extend the study scopes of integrable couplings, the notion of double integrable couplings is proposed in the paper. The zero curvature equation appearing in the constructing method built in the paper consists of the elements of a new loop algebra which is obtained by using perturbation method. Therefore, the approach given in the paper has extensive applicable values, that is, it applies to investigate a lot of double integrable couplings of the known integrable hierarchies of evolution equations. As for explicit applications of the method proposed in the paper, the double integrable couplings of the AKNS hierarchy and the KN hierarchy are worked out, respectively.

Double Covalency Factors and DoubleξModel in Study on Optical and Magnetic Properties of Diluted Magnetic Semiconductors ZnX∶Co~ 2+

The optical absorption spectra of the covalent crystals ZnX(X=S,Se) doped with Co 2+ are studied using the double covalency factors,which considers the anisotropic distortion of e g and t 2g orbits for d electron.When the paramagnetic g factor is calculated,the contributions of the spin orbit coupling from the ligand ions are taken into account besides that from the central ion,which is the double ξ model.The calculated results indicate that the theoretical values coincide with the experimental values very well.This suggests that the method presented in this paper could be more valid to some strongly covalent crystals.

Phase Control of Transient Optical Properties of Double Coupled Quantum-Dot Nanostructure via Gaussian Laser Beams

We theoretically analyze the transient properties of a probe field absorption and dispersion in a coupled semiconductor double-quantum-dot nanostructure.We show that in the presence of the Gaussian laser beams,absorption and dispersion of the probe field can be dramatically influenced by the relative phase between applied fields and intensity of the Gaussian laser beams.Transient and steady-state behaviors of the probe field absorption and dispersion are discussed to estimate the required switching time.The estimated range is between 5-8 ps for subluminal to superluminal light propagation.

Double coupled fixed point for multi-valued mixed increasing operators in ordered Banach spaces

In this paper, a new concept of double coupled fixed point for multi-valued mixed increasing operators is given and some new double coupled fixed point theorems for multi-valued mixed increasing operators in ordered Banach spaces are also given. These results extend and generalize some results of Huang and Fang.

Approximate Controllability of the System Governed by Double Coupled Semilinear Degenerate Parabolic Equations

This paper concerns the approximate controllability of the initialboundary problem of double coupled semilinear degenerate parabolic equations.The equations are degenerate at the boundary,and the control function acts in the interior of the spacial domain and acts only on one equation.We overcome the difficulty of the degeneracy of the equations to show that the problem is approximately controllable in L2 by means of a fixed point theorem and some compact estimates.That is to say,for any initial and desired data in L2,one can find a control function in L2 such that the weak solution to the problem approximately reaches the desired data in L2 at the terminal time.

Theoretical Investigations of the Local Structure Distortion and EPR Parameter for Ni2＋-doped Perovskite Fluorides

By analyzing the optical spectra and electron paramagnetic resonance parameter D, the local structure distortion of （NiF6）4- clusters in AMF3 （A=K, Rb; M=Zn, Cd, Ca） and K2ZnF4 series are studied using the complete energy matrix based on the double spin-orbit coupling parameter model for configuration ions in a tetragonal ligand field. The results indicate that the contribution of ligand to spin-orbit coupling interaction should be considered for our studied systems. Moreover, the relationships between D and the spin-obit coupling coefficients as well as the average parameter and the divergent parameter are discussed.

Strain effects on performance of electroabsorption optical modulators

This paper reports a detailed theoretical investigation of strain effects on the performance of electroabsorption optical modulators based on the asym- metric intra-step-barrier coupled double strained quantum wells （AICD-SQWs） active layer. For this purpose, the electroabsorption coefficient was calculated over a range of AICD-SQWs strain from compressive to tensile strain. Then, the extinction ratio （ER） and insertion loss parameters were evaluated from calculated electroabsorp- tion coefficient for transverse electric （TE） input light polarization. The results of the simulation suggest that the tensile strain from 0.05% to 0.2% strain in the wide quantum well has a significant impact on the ER and insertion loss as compared with compressive strain, whereas the compressive strain of the narrow quantum well from -0.5% to -0.7% strain has a more pronounced impact on the improvement of the ER and insertion loss as compared with tensile strain.