硅藻检验中应注意的新问题

处理溺死案件时,对死者脏器组织、牙齿和骨髓等进行硅藻检验是判断是否为溺死的重要手段：硅藻的检验方法多种多样,通过简要介绍几种常用方法的不同之处,针对硅藻检验中易出现的问题展开探讨,特别就易干扰检验结果的各种因素如在不同条件下同一水源的硅藻变化、潮汐和汇流的影响以及外界污染等问题展开讨论,以期引起检验者的重视。     

Impact of small-world topologies on broadcasting for wireless sensor networks

Broadcasting is an important operation and been widely used in wireless sensor networks (WSNs). These networks are power constrained as nodes operate with limited battery power. Wireless sensor networks are spatial graphs that have much more clustered and much high path-length characteristics. After considering energy-efficient broadcasting in such networks, by combining the small-world characteristic of WSNs and the properties of ant algorithm to quickly identify an optimal path, small-world power-aware broadcast algorithm is introduced and evaluated. Given different densities of network, simulation results show that our algorithm significantly improves life of networks and also reduces communication distances and power consumption.     

基于ESPRIT方法的近场源参数估计

提出了一种基于ESPRIT的近场窄带信源到达角及距离联合估计新方法。该方法选择特定序号阵元输出计算的四阶累积量构造高维矩阵,利用其特征值分解结果构造2个新的矩阵,再借助新构造矩阵的特征值联合估计信源参数。该方法无须参数配对,无须谱峰搜索;有效利用了阵列孔径,从而具有较高的估计精度。仿真结果表明算法是有效的。     

基于OpenGL索引顶点数组的大尺度海面LOD算法

分析了大尺度海面与地形数据的区别,提出一种基于OpenGL索引顶点数组的细节层次(LOD)算法.采用视点相关技术,建立了一种网格模板,将每级网格划分为8个矩形区域和4个T型裂缝缝补区域,使用索引顶点数组高效绘制所有区域.根据视点进行可见性判断,对可见点使用P-M海浪谱实时反演海面数据,逼真地实现了大尺度海面的漫游.     

迪斯尼跨文化管理的启示

伴随着世界经济一体化进程的不断发展,世界范围内跨文化的经济合作日益频繁,由文化差异给企业带来的碰撞和冲突日益彰显突出。本文通过对迪斯尼在日本和法国的跨国经营成败的分析,指出文化差异对跨国经营的一系列影响,同时对跨国企业应怎样做好市场调研、进行跨文化管理以及如何利用文化差异获得竞争优势进行了阐述。     

农村顶岗支教：培养科学教师的有效模式

农村顶岗支教是指让学生到农村中小学的教育教学岗位上,进行为期一个学期的教育教学实践,以锻炼与提高他们的教育教学能力与水平,培养合格师资的人才培养模式.该模式培养科学课师资具有四大优越性:一是有利于培养科学教育专业学生的职业素质,二是有利于培养科学教育专业学生的综合素质,三是有利于解决科学教育专业学生的毕业实习,四是有利于解决农村科学课师资匮乏的现实.目前,顺利实施该培养模式急需解决政策疲软、经费欠缺、舆论不足等三大问题.     

蝴蝶翅膀表面超微结构与浸润性机理分析

用热场发射扫描电子显微镜和接触角测量仪观测迁粉蝶、密纱眉眼蝶、素饰蛱蝶、绿带翠凤蝶和黑绢斑蝶翅膀表面的超微结构,测量其静态接触角和滚动角,测量分析表明: 蝴蝶翅膀表面覆盖着重叠排列的瓦片状鳞片,鳞片上分布有纵隆脊和肋,相邻脊脉与肋间形成了凹坑;鳞片的排间距、脊和肋按蝴蝶种类的不同而具有不同的尺寸.有鳞片翅膀表面的接触角在 139.7°～158.9°之间,明显大于无鳞片翅膀表面的接触角(88°～144°),正向、逆向和垂直翅脉发散方向的滚动角不同,翅膀表面的超微结构导致其具有各向异性的浸润性.     

基于输水隧洞泵送混凝土管道的冲蚀机理

采用数值模拟方法对龙开口水电站1号输水隧洞混凝土泵送过程中管道冲蚀磨损问题进行研究。利用DPM离散相模型分析泵送管道的冲蚀磨损机理,结合1号隧洞实际泵送混凝土的情况来验证数值模型是否正确。通过模拟结果从整个管道固相体积分数分布与弯管出口处的压强变化等特征理解其内在的多相流动规律。模拟得到的弯管最大冲蚀磨损部位,与实际泵送过程中的磨损部位吻合较好。说明DPM冲蚀模型能准确预测泵送管道的磨损特性,可为类似的泵送混凝土施工提供有益参考。     

n-Pentylamine-intercalated layered perovskite-type oxide

A novel n-pentylamine-intercalated layered perovskite-type oxide, C5H11NH3-Sr2Nb3O10, was prepared and characterized by using XRD, FT-IR, Raman spec-trascopy, and elemental analysis. It was shown that the intercalated n-pentylamine adopted a bilayer formation with some overlap and tilt, and the lattice of the perovskite layer was distorted due to the intercalation of n-pentylamine. The as-prepared sample gave clear electric hysteresis loop and did not show fatigue after 1011 switching circles, and therefore, could be considered as a new kind of fatigue-free ferroelectric materials.     

Contemporary crustal movement of continental China obtained by global positioning system (GPS) measurements

We obtain a unified horizontal velocity field of continental China and vicinity through measurements at 81 GPS stations provided by the National Key Infrastructure Project, Crustal Movement Observation Network of China. The velocity field delineates patterns of movements and deformation of active crustal blocks in continental China under the Eurasia-fixed reference frame. The space-based geodesy also clearly shows for the first time the horizontal movement and deformation of continental China induced by indentation of the Indian plate. The data provide kinematic constraints for simulating dynamic process of continental lithospheric deformation.