Dynamical analysis,circuit realization,and application in pseudorandom number generators of a fractional-order laser chaotic system

A new five-dimensional fractional-order laser chaotic system (FOLCS) is constructed by incorporating complex variables and fractional calculus into a Lorentz-Haken-type laser system. Dynamical behavior of the system, circuit realization and application in pseudorandom number generators are studied. Many types of multi-stable states are discovered in the system. Interestingly, there are two types of state transition phenomena in the system, one is the chaotic state degenerates to a periodical state, and the other is the intermittent chaotic oscillation. In addition, the complexity of the system when two parameters change simultaneously is measured by the spectral entropy algorithm. Moreover, a digital circuit is design and the chaotic oscillation behaviors of the system are verified on this circuit. Finally, a pseudo-random sequence generator is designed using the FOLCS, and the statistical characteristics of the generated pseudo-random sequence are tested with the NIST-800-22. This study enriches the research on the dynamics and applications of FOLCS.     

基于多金属氧酸盐和贵金属的纳米复合材料的研究进展

基于多金属氧酸盐和贵金属纳米粒子的纳米复合材料,既具有多金属氧酸盐(POMs)可调控的多样结构、丰富的组成、高的电荷密度及可逆的氧化还原性,又具有贵金属纳米材料良好的生物相容性、高的光学活性和催化活性等特性,这些性质使基于POMs和贵金属纳米的复合材料能够应用于催化、生物医药、生物传感等领域.本文作者主要论述近年来基于多金属氧酸盐和贵金属的纳米复合材料的合成、性质及应用的研究现状,并对其前景进行展望.     

贵金属杂化纳米材料的合成及性能研究进展

近年来,杂化纳米材料的出现极大地拓展了纳米材料的应用范围,其特殊的结构、性能、尺寸和形貌使其不仅保持了各组分材料的特性及功能,更涌现了不同于各组分材料所不具备的新颖的、多样化的特殊性能和应用潜能,因此其制备方法和性能应用已经成为了研究热点.运用纳米技术将贵金属纳米粒子与其他性能优异的物质结合形成的贵金属杂化纳米材料被广泛运用到电化学、光催化、免疫传感、生物催化和医药化学等领域.本文综述了贵金属杂化纳米材料的制备方法、结构组成、性能特点、应用前景以及最新的发展趋势,重点介绍了贵金属杂化纳米材料的合成及应用.