时滞BAM神经网络周期解的存在性和全局指数稳定性

本文利用迭合度理论,通过构造适当的Lyapunov泛函并结合Yang不等式分析技巧,获得了具周期系数的时滞BAM神经网络周期解的存在性和全局指数稳定性的充分条件,这些结果对设计全局指数稳定的BAM神经网络与周期振荡的BAM神经网络具有重要的指导意义.     

Defect chemistry and VUV optical properties of the BaMgAl10O17:Eu-Ba0.75Al11O17.25:Eu solid solution

The optical properties of the BaMgAl₁₀O₁₇:Eu²⁺ (BAM)-Ba_0.75Al₁₁O_17.25:Eu²⁺ (BAL) solid solution have been studied using VUV excitation, emission and reflectance spectroscopy. Three unique Eu²⁺ emission centers are observed in a ratio that depends on the composition of the host and the dopant concentration. Two of the emission centers are assigned to Eu on normal Beevers-Ross sites and Eu on anti Beevers-Ross sites. The defect chemistry of this system is modeled based on the known behavior of the spinel (MgO·nAl₂O₃) system. Based on this model, the third Eu center can be assigned either to Eu near Al vacancies or to Eu associated with O atoms in the cation layer. In undoped materials exciton emission is observed, peaking at 263 nm in BAM and 285 nm in BAL. This emission may be the mechanism of host-to-activator energy transfer in these phosphors.     

BAM人工神经网络的几个性质

ＢＡＭ双向联想式神经网络是一种重要的反馈式神经网络，它具有较好的分析映射能力．详细论述了ＢＡＭ的等价性；ＢＡＭ网络的双向稳定性以及网络的动态搜索，匹配过程．笔者将其用于地层损害的识别及分析，收到了良好的效果．     

Low-temperature synthesis of fine BaMgAl10O17:Eu phosphor based on the solubility isotherms

A homogeneous and stoichiometric BaMgAl₁₀O₁₇:Eu²⁺ (BAM) phosphor powder has been prepared by the citrate route. Solubility isotherms have been calculated for metal-citric acid-water system at 25 °C to predict the optimum pH condition, which was found to be pH=7 for preparing pure and stable metal citrate complexes. Well crystallized and sub-micrometer-sized BAM particles could be obtained by thermal decomposition of the optimally prepared citrate precursor at a temperature as low as 1150 °C. Though the luminescent properties of the present samples under UV excitation well reflect the bulk properties, VUV excitation has exhibited the luminescent properties greatly influenced by the surface, which might be due to the fine particle. The maximum luminance of the samples heat treated at 1350 °C was 105% in comparison with that of the commercial BAM under VUV excitation.     

Synchronization of memristor‐based delayed BAM neural networks with fractional‐order derivatives

This article deals with the problem of synchronization of fractional‐order memristor‐based BAM neural networks (FMBNNs) with time‐delay. We investigate the sufficient conditions for adaptive synchronization of FMBNNs with fractional‐order 0 < α < 1. The analysis is based on suitable Lyapunov functional, differential inclusions theory, and master‐slave synchronization setup. We extend the analysis to provide some useful criteria to ensure the finite‐time synchronization of FMBNNs with fractional‐order 1 < α < 2, using Mittag‐Leffler functions, Laplace transform, and linear feedback control techniques. Numerical simulations with two numerical examples are given to validate our theoretical results. Presence of time‐delay and fractional‐order in the model shows interesting dynamics. © 2016 Wiley Periodicals, Inc. Complexity 21: 412–426, 2016     

含时延和扰动的连续BAM神经网络的稳定性和指数收敛速度估计

采用不等式技巧和Lyapunov函数，分析了含时延和扰动的连续BAM神经网络平衡点的存在前提，平衡点渐近稳定的充分条件以及平衡点的指数收敛速度．     

PDP用纳米BaMgAl10O17:Eu荧光粉的燃烧合成及发光性能

采用溶液燃烧合成法直接合成了PDP用纳米BaMgAl10O17∶Eu(BAM)荧光粉, 并对产物进行了XRD、TEM分析和发光性能测试. 结果表明, 合成产物由单一的BAM组成, 且结晶完好, 不存在位错、孪晶等缺陷；BAM颗粒近似球形, 平均粒径约为20 nm；在334 nm UV光激发下, 样品的发射峰值波长为450 nm, 归属于Eu2+离子的4f 65d→ 4f 7(8S7/2)宽带允许跃迁, 与稀土三基色荧光材料中的蓝色组分发光完全一致. 与高温固相法相比, 燃烧合成法具有合成温度低, 反应时间短, 所得产物纯净且颗粒细小, 发光强度高等优点.     

Exponential Stability of Positive Conformable BAM Neural Networks with Communication Delays

In this paper, we consider a class of nonlinear differential equations with delays described by conformable fractional derivative. This type of differential equations can be used to describe dynamics of various practical models including biological and artificial neural networks with heterogeneous time-varying delays. By novel comparison techniques via fractional differential and integral inequalities, we prove under assumptions involving the order-preserving property of nonlinear vector fields that, with nonnegative initial states and inputs, the system state trajectories are always nonnegative for all time. This feature, called positivity, induces a special character, namely the monotonicity of the system. We then derive tractable conditions in terms of linear programming and prove, by utilizing the Brouwer''s fixed point theorem and comparisons induced by the monotonicity, that the system possesses a unique positive equilibrium point which attracts exponentially all state trajectories. An application to the exponential stability of fractional linear time-delay systems is also discussed. Numerical examples with simulations are given to illustrate the theoretical results.     

变时滞脉冲BAM神经网络的稳定性(英文)

本文研究了当脉冲不太频繁易受大的脉冲影响下的时滞BAM神经网络具有唯一的指数稳定的平衡点.分析采用一个推广的比较原理和M-矩阵理论,得到一些关于唯一平衡点的收敛性的简单可行的充分条件.所得结果推广和改进了已有文献的结果.     

BAM神经网络周期解的存在性及全局稳定性

讨论了具有分布时滞的双向联想记忆(BAM)神经网络的动力学行为。利用迭合度理论的延拓定理和分析技巧,得到了周期解的存在性和全局稳定性的充分条件,对设计这种类型的神经网络具有重要意义。