Influence of Mg/Er co‐doping on the principal laser parameters of LiNbO3 crystals

Mg: Er: LiNbO₃ crystals were grown by the Czochralski technique with various concentrations of MgO = 2 mol%, 4 mol%, 6 mol% and the fixed concentration of Er₂O₃= 1 mol% in the melt, and the 8 mol%Mg: 1 mol%Er: LiNbO₃ crystal was fabricated by the Czochralski technique with special technology process. The crystals were treated by polarization, reduction and oxidation. The segregation coefficients of Mg²⁺ and Er³⁺ in Mg: Er: LiNbO₃ crystals were measured by X‐ray fluorescence spectrograph, as well as the crystal's defect structure and optical properties were analyzed by the UV‐Vis, IR and fluorescent spectroscopy. The pump wavelength and the surge wavelength were determined. Using m‐line method tested optical damage resistance of those crystals, the results show that photodamage threshold of Mg: Er: LiNbO₃ crystals are higher than that of Er: LiNbO₃ crystal, and the oxidation treat could enhance the photodamage resistant ability of crystals while the reduction treat could depress the ability. The optical damage resistance of 8 mol%Mg: 1 mol%Er: LiNbO₃ crystal was the strongest among the samples, which was two orders magnitude higher than that of 1 mol%Er: LiNbO₃ crystal. The dependence of the optical properties on defect structure of Mg: Er: LiNbO₃ crystals was discussed. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Local Weighted Composite Quantile Estimating for Varying Coefficient Models

A generalization of classical linear models is varying coefficient models, which offer a flexible approach to modeling nonlinearity between covariates. A method of local weighted composite quantile regression is suggested to estimate the coefficient functions. The local Bahadur representation of the local estimator is derived and the asymptotic normality of the resulting estimator is established. Comparing to the local least squares estimator, the asymptotic relative efficiency is examined for the local weighted composite quantile estimator. Both theoretical analysis and numerical simulations reveal that the local weighted composite quantile estimator can obtain more efficient than the local least squares estimator for various non-normal errors. In the normal error case, the local weighted composite quantile estimator is almost as efficient as the local least squares estimator. Monte Carlo results are consistent with our theoretical findings. An empirical application demonstrates the potential of the proposed method.     

Solutions for a generalized fractional anomalous diffusion equation

In this paper, we investigate the solutions for a generalized fractional diffusion equation that extends some known diffusion equations by taking a spatial time-dependent diffusion coefficient and an external force into account, which subjects to the natural boundaries and the generic initial condition. We obtain explicit analytical expressions for the probability distribution and study the relation between our solutions and those obtained within the maximum entropy principle by using the Tsallis entropy.     

A neural network for solving a convex quadratic bilevel programming problem

A neural network is proposed for solving a convex quadratic bilevel programming problem. Based on Lyapunov and LaSalle theories, we prove strictly an important theoretical result that, for an arbitrary initial point, the trajectory of the proposed network does converge to the equilibrium, which corresponds to the optimal solution of a convex quadratic bilevel programming problem. Numerical simulation results show that the proposed neural network is feasible and efficient for a convex quadratic bilevel programming problem.     

Traveling waves of some integral-differential equations arising from neuronal networks with oscillatory kernels

In this paper, we study the existence, uniqueness and profiles of traveling waves to some integral-differential equations arising from nonlinear nonlocal neuronal networks with oscillatory kernels. Our approach is fundamental ideas in differential equation and function analysis.     

Toeplitz Operators from One Fock Space to Another

In this paper, we study Toeplitz operators T _μ from one Fock space \({F^{p}_{\alpha}}\) to another \({F^{q}_{\alpha}}\) for 1 < p, q < ∞ with positive Borel measures μ as symbols. We characterize the boundedness (and compactness) of \({T_\mu: F^{p}_{\alpha} \to F^{q}_{\alpha}}\) in terms of the averaging function \({\widehat{\mu}_r}\) and the t-Berezin transform \({\widetilde{\mu}_t}\) respectively. Quite differently from the Bergman space case, we show that T _μ is bounded (or compact) from \({F^{p}_{\alpha}}\) to \({F^{q}_{\alpha}}\) for some p ≤ q if and only if T _μ is bounded (or compact) from \({F^{p}_{\alpha}}\) to \({F^{q}_{\alpha}}\) for all p ≤ q. In order to prove our main results on T _μ , we introduce and characterize (vanishing) (p, q)-Fock Carleson measures on C ⁿ .     

Feasibility study on strengthening heating effect of high power short pulse laser on biological tissue by micro/nano metal particles

A new method for enhancing the heating effect of high power short pulse laser on biological tissue by micro/nano metal particles was proposed. Theoretical analysis of the influences of the micro/nano particle kind, the concentration and the microcosmic distribution of micro/nano particles on the temperature response was carried out with a multi-layer hyperbolic heat conduction model with volumetric heat generation. The results indicate that embedding micro/nano particles could improve the surface temperature increase of biological tissue with short duration and reduce the deeper material temperature under the same heating condition, which would help strengthen the heating effects of high power short pulse laser on biological tissue. This study may open a new technical approach for improving laser applications.     

A novel photoalignment film for ferroelectric liquid crystal based on self-assembled monolayer method

A novel strategy based on self-assembly technology was devised for design of photosensitive material as a ferroelectric liquid crystal (FLC) alignment layer. This development offers new tools for the study and control at the molecular level of the interaction of FLCs with solid surfaces. The photoreactive material was self-assembled to the substrate by covalent bond linkage due to a special chemical adsorption reaction. Through ester bond linkage, a cyano group with strong polarity was introduced to be terminus of the film. Under irradiation of linearly polarised ultraviolet light, an optically anisotropic self-assembled film was easily obtained. The irradiated film was demonstrated to result in homogenous alignment of FLC by optical transmittance measurements and polarising optical microscopy images of a FLC cell at different rotation angles. The alignment quality of the FLC on this self-assembled monolayer film is comparable to that of commercial rubbed polyimide film. Furthermore, it was also found that the fine alignment of the FLC may be related to the smoothness of the self-assembled film surface owing to its polar end.