新三维混沌系统的动力学研究及其仿真

借助一个适当的Lyapunov函数和最优化理论研究了一个新的三维混沌系统的全局指数吸引集,得到了该系统的一族全局指数吸引集表达式。并且通过计算机进行了模拟。     

融合傅里叶描述子和尺度不变特征转换特征的商标检索

针对传统商标检索算法中全局特征容易造成误检,而局部特征SIFT对轮廓描述能力不强及算法复杂度高的问题,提出了一种融合图像全局特征和局部特征的商标检索算法。其中全局特征反应了图像的整体信息,这些信息可用来较快地建立候选图像库,而局部特征则可以更准确地与候选图像进行匹配。首先提取图像的傅里叶描述子进行初步检索,并按相似度排序,然后在此结果集的基础上对候选图像通过提取SIFT特征进行精确匹配。实验结果表明,该方法既保持了SIFT特征较高的查全率和查准率,优于傅里叶描述子单一特征,而且检索速度比SIFT单一特征显著提高,能很好地应用于商标图像检索系统中。     

雨水在山东省景观水系中的利用

山东省是一个资源性缺水大省,解决各类用水的水源是各类用水设计的关键.各类景观水系需要大量的水源来补充,而利用雨水作为景观水系的一种水源是解决水景水源的一种重要方法.本文以雨水在居住区景观水系的利用为例,详细分析、论述了雨水在山东省景观水系中应用的意义、原则、分类、方法,以期对雨水应用于山东省景观水系的设计起到一定的借鉴...     

线性反馈控制在保密通信中的应用

为解决保密通信中信息解密的混沌同步问题,提出一种混沌同步的线性反馈控制方法。证明混沌保密通信中混沌系统的最终有界 性,将该混沌系统的界应用到混沌同步中,用线性反馈控制实现2个混沌系统的完全同步。计算机模拟实验结果验证了该方法的有效性。     

两层镀膜长周期光纤光栅传感器的特性研究

以光纤光栅耦合模理论为基础,提出一种两层镀膜长周期光纤光栅传感器的结构模型,一层是在光纤包层外镀的铜金属薄膜,另一层是在铜薄膜外再镀一层敏感薄膜.对该结构模型的模场特性和透射特性进行分析和模拟,明确了薄膜参数对其透射特性的影响.该结构模型既可以利用敏感膜折射率随外界环境变化而改变的特性,也可以利用金属膜层进行温度和应变...     

锑-溴酸钾-偶氮胭脂红B催化动力学光度法测定痕量锑

锑及其化合物是全球性污染物,易造成环境污染。但是,锑的催化效果差,测定锑的动力学光度法相对较少。在磷酸介质中,痕量锑(III)对溴酸钾氧化偶氮胭脂红B褪色反应有催化作用,据此,建立了动力学光度法测定锑的新方法。在两只比色管中分别加入适量的锑(III)样品溶液(催化反应,吸光度A)和同量的水(非催化反应,吸光度A₀),再分别加入0.7mL 4.0×10^-3 mol/L溴酸钾溶液、1.8mL 1.0mol/L磷酸和2.2mL 0.5g/L偶氮胭脂红B溶液,然后在90℃水浴中加热15min,在波长515nm处测定体系的吸光度A和A₀。实验结果表明,表观活化能Ea=33.6kJ/mol,锑的质量浓度在0.02~0.26μg/mL范围内与lg(A₀ /A)呈良好的线性关系,检出限为8.79×10^-9 g/mL。对复杂样品河泥的测定,先采用萃取的方法,规避了共存离子的干扰,再采用实验方法测定锑,结果的相对标准偏差(RSD,n=6)为3.3%~3.5%;加标回收率为96%~98%;并与原子荧光光谱法测定结果相吻合。     

Facile synthesis and characterization of urchin-like CdSe nanostructures

CdSe nanostructures with urchin-like shape were successfully synthesized in water-in-oil (W/O) microemulsion. The phase structure, morphology, optical property, and specific surface area of the CdSe products were characterized. The X-ray powder diffraction pattern of the product showed that it is pure CdSe in zinc blende structure rather than thermodynamically favored wurtzite structure. It is found that numerous one-dimensional CdSe nanorods radiate from the center of the agglomerate to form urchin-like nanostructures and grow along the (111) crystal planes. The photoluminescence spectrum of the urchin-like nanostructures indicated that there is a blue-shift as compared with that of the bulk CdSe. Additionally, these interesting urchin-like nanostructures showed an increased specific surface area.     

交错转换模式PFC原理与设计

交错转换模式（TM）是一种功率因数校正（PFC）控制方法。交错双相TM-PFC允许升压变换器获得180。的相位移和在TM操作，致使输入和输出电容器上的纹波电流大大地减小。介绍了交错双相TM-PFC的基本原理和基于UCC28060控制器的交错双相TM-PFC变换器的设计。     

Fundamental limitations and intrinsic limits of feedback: An overview in an information age

This paper presents a review on the fundamental performance limitations and design tradeoffs of feedback control systems, ranging from classical performance tradeoff issues to the more recent information-theoretic analysis, and from conventional feedback systems to networked control systems, with an attempt to document some of the key achievements in more than seventy years of intellectual inquiries into control performance limitation studies, as so embodied by the timeless contributions of Bode known as the Bode integral relations.     

Atomic chemisorption on graphene with Stone–Thrower–Wales defects

Using first-principles calculations, we investigate the chemisorption of H, N, and P atoms on a graphene substrate with or without Stone–Thrower–Wales (STW) defects. Energetically, all three atoms are preferred to adsorb onto the defect sites by an energy difference of ∼0.683–2.143 eV. In both the intrinsic and defected graphene, H atom adsorbs on top of a C atom, while N and P atoms adsorb at the bridge site between two C atoms with the N atom breaking the underneath C–C bond in the STW defect. Changes of atomic, electronic and magnetic structures associated with the atomic chemisorption on STW defects in graphene are discussed.