Mechanisms of extensive spatiotemporal chaos in Rayleigh-Benard convection

Spatially extended dynamical systems exhibit complex behaviour in both space and time--spatiotemporal chaos. Analysis of dynamical quantities (such as fractal dimensions and Lyapunov exponents) has provided insights into low-dimensional systems; but it has proven more difficult to understand spatiotemporal chaos in high-dimensional systems, despite abundant data describing its statistical properties. Initial attempts have been made to extend the dynamical approach to higher-dimensional systems, demonstrating numerically that the spatiotemporal chaos in several simple models is extensive (the number of dynamical degrees of freedom scales with the system volume). Here we report a computational investigation of a phenomenon found in nature, 'spiral defect' chaos in Rayleigh-Benard convection, in which we find that the spatiotemporal chaos in this state is extensive and characterized by about a hundred dynamical degrees of freedom. By studying the detailed space-time evolution of the dynamical degrees of freedom, we find that the mechanism for the generation of chaotic disorder is spatially and temporally localized to events associated with the creation and annihilation of defects.     

苯酚-硫酸法测定藏木香中多糖含量

采用传统的水煮醇沉法从藏木香中提取可溶性多糖,通过Sevag法脱蛋白后,以葡萄糖为对照品,使用苯酚-硫酸法测定多糖含量.结果表明,在波长486nm处测定吸光度,10-100μg/mL范围内吸光度与被测含量之间具有良好的线性关系,藏木香中多糖的含量为64.37%.     

钢管相贯口变参数变结构建库与数据提取方法研究

零件的批处理和零件库的建立是计算机辅助设计的重要内容之一，以钢管相贯口为例应用UG的几种建库方法，通过分析电子表格、零件族、GRIP编程在变参变结构的复杂零件建库时存在的问题，提出了一种将零件族和GRIP编程相结合的建库方法来建立变参变结构的复杂零件的零件库。     

甘青青兰挥发性成分GC/MS分析

目的：分离鉴定出甘青青兰（Dracocephalum tanguticum Maxim.）挥发油的化学成分.方法：用气相色谱-质谱（GC/MS）联用技术及峰面积归一化法测定各组分的相对含量.结果：共鉴定出23种化合物,占总色谱峰总面积的87.46%.结论：甘青青兰挥发油中的化学成分主要为[-]-反-松香芹乙酯和桉油精,两者分别占总挥发油中化学成分的60.30%和9.31%.     

带有时变时滞的中立型随机系统的鲁棒镇定和H_∞控制

研究了带有时变时滞的中立型随机系统的鲁棒镇定和H∞控制问题.利用Lyapunov泛函方法和It o^公式,基于状态反馈控制器,以线性矩阵不等式(LMI)形式给出了闭环系统鲁棒镇定及H∞控制的新方法.最后,数值算例说明了该方法的有效性.     

论竞技健美操技术创新的概念与分类

该研究以竞技健美操技术创新为研究对象,采用文献资料法、案例分析法,对查阅的文献和案例进行综合的归纳分析,在研究竞技健美操技术创新发展现状基础上,结合其他项目技术创新的特点,对竞技健美操技术创新的概念进行了阐述;对竞技健美操技术创新进行了系统的分类.