金属丝壁面加热湍流标度律的实验研究

通过在固壁表面的平板湍流边界层沿流向平行放置若干通电加热的金属细丝,在平板表面形成沿展向周期性分布的温度场,利用该温度场引起的空气热对流,在湍流边界层近壁区域产生一组沿湍流边界层展向周期分布的流向涡结构。对壁湍流小尺度结构标度律统计特性的研究表明,金属丝加热后形成的规则流向涡结构将壁湍流各种尺度湍涡结构不规则的脉动有序地组织起来,增强了湍流小尺度结构的层次结构相似性,减小了壁湍流中小尺度结构的间歇性和奇异性,抑制了壁湍流中奇异的湍涡结构。     

自由湍射流边界层标度律的实验测量

用IFA300热线风速仪以低于最小低湍流时间尺度的高分辨率，精细测量了圆自由射流中同一流向断面内不同径向位置的流向速度分量，研究了不同径向位置的非均匀、非各向同性对充分发展湍流速度结构函数自相似标度律及其层次结构模型的影响。     

Microwave-hydrothermal preparation of a graphene/hierarchy structure MnO2 composite for a supercapacitor

Graphene/hierarchy structure manganese dioxide （GN/MnO2） composites were synthesized using a simple microwave-hydrothermal method. The properties of the prepared composites were analyzed using field emission scanning electron microscopy （FE-SEM）, X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and X-ray photoelectron spectroscopy （XPS） measurements. The electrochemical performances of the composites were analyzed using cyclic voltammetry, electrochemical impedance spectrometry （EIS）, and chronopotentiometry. The results showed that GN/MnO2 （10 wt% graphene） displayed a specific capacitance of 244 F/g at a current density of 100 mA/g. An excellent cyclic stability was obtained with a capacity retention of approximately 94.3% after 500 cycles in a 1 mol/L Li2SO4 solution. The improved electrochemical performance is attributed to the hierarchy structure of the manganese dioxide, which can enlarge the interface between the active materials and the electrolyte. The prepa- ration route provides a new approach for hierarchy structure graphene composites; this work could be readily extended to the preparation of other graphene-based composites with different structures for use in energy storage devices.     

不分明拓扑的层次结构

不分明拓扑较之分明拓扑多了一个层次结构.本文讨论了不分明集与其各层截集以及不分明拓扑与其层次拓扑之间的关系,给出了存在不分明集使其各层截集为给定的一族分明集的充要条件,进而给出了存在不分明余拓扑使其层次拓扑为给定的一族分明余拓扑的充要条件.本文还就相关的问题作了一些讨论,得出了一些有趣的结果.     

Exact Solutions for Two Equation Hierarchies

Bilinear forms and double-Wronskian solutions are given for two hierarchies, the （2＋1）-dimensional breaking Ablowitz-Kaup-Newell-Segur （AKNS） hierarchy and the negative order AKNS hierarchy. According to some choices of the coefficient matrix in the Wronskian condition equation set, we obtain some kinds of solutions for these two hierarchies, such as solitons, 3ordan block solutions, rational solutions, complexitons and mixed solutions.     

The Multi-Function Jaulent-Miodek Equation Hierarchy with Self-Consistent Sources

The multi-functions of soliton equation hierarchy with self-consistent sources is constructed. Then, the Jaulent- Miodek （3M） equation hierarchy with self-consistent sources is derived. Furthermore, the multi-function 3M equation hierarchy with self-consistent sources is presented by using the higher-dimensional Lax pairs.     

一类图形问题的求解

从有实际应用背景的问题出发，提出了一种求解一类图形中结点路径长度的方法．该方法利用层次结构的特点，将图的计算递归转换为图的构造递归．用非递归程序来求解．在构造图的同时完成计算，并在PowerBuilder上予以实现．最后对算法作出了分析和评价．