基于ARM的列车运行控制算法仿真测试系统

介绍了列车运行控制系统的基本组成和原理,采用通用ARM芯片S3C2440设计了列车运行控制仿真硬件系统以及包含列车模型的PC端仿真软件.使用串口UART实现下位机控制系统硬件和上位机列车仿真模型软件之间的数据通信.最后,设计了基于滑动模态状态观测器的列车控制算法,并在仿真测试系统中进行了测试.     

高功率光纤激光焊金属蒸气图像辐射亮度的三维重建

以光纤传像束为基础搭建激光焊金属蒸气的多角度同步成像平台,从平台的3个方向获取金属蒸气的二维投影图像,并以二维投影图像为基础,采用基于中心投影模型的代数迭代法进行金属蒸气图像的三维重建,以获得金属蒸气图像辐射亮度的三维分布.结果表明:对于高功率激光焊接而言,金属蒸气图像的辐射亮度呈现出由内到外而逐渐降低的变化趋势,其中心部分的辐射亮度分布并不连续,且存在相对孤立的离散区域;当匙孔的开口与激光入射点重合时,金属蒸气的尺寸较小且贴近于工件表面;当熔池波动而造成匙孔失稳时,金属蒸气图像出现了形态异常和较为显著的尺寸变化.     

基于阈值故障子空间提取算法的多重故障重构

在统一框架下考虑了多重传感器故障的故障检测与故障重构问题.传感器的多种失效模式给过程监控和故障重构带来了一定的挑战.首先,提出一种可以同时表示加性和乘性传感器故障的故障模型.从数据驱动的角度出发,多重故障可检测性的必要条件和充分条件通过RayleighRitz引理被推导出来.进一步,提出了一种基于阈值故障子空间提取算法的多重故障重构方法.数值仿真表明,所提出的故障重构方法在重构误差指标方面明显优于传统的故障重构方法,验证了文中给出的主要结果.     

原位叶绿素a光纤荧光传感器研制

运用荧光检测技术,设计了一款用于海水中叶绿素a含量检测的在线式光纤传感器。该传感器基于光纤传输与荧光分析法,通过对激发荧光信号的捕捉、传输以及解析达到在线快速检测叶绿素a的目的。实验结果表明,该传感器的响应值与叶绿素a的浓度具有良好的线性关系,检测性能稳定,且具有体积小、传输速度快等特点,初步具备了海水中叶绿素a含量的现场检测能力。     

一种基于可靠预约ALOHA的智能车多车协作通信协议

针对典型交通场景下智能车多车协作的实时性、可靠性及分布式协作的要求,提出了基于可靠预约ALOHA的介质访问层信道接入协议,通过使用动态时分复用信道而提高车间通信的实时性,用预约时隙和广播机制而提高通信的可靠性与分布式特性,并设计了针对车队和超车的多车协作算法.同时,通过实验验证了通信协议及系统的可行性与可靠性.     

Highly specialized mammalian skulls from the Late Cretaceous of South America

Dryolestoids are an extinct mammalian group belonging to the lineage leading to modern marsupials and placentals. Dryolestoids are known by teeth and jaws from the Jurassic period of North America and Europe, but they thrived in South America up to the end of the Mesozoic era and survived to the beginnings of the Cenozoic. Isolated teeth and jaws from the latest Cretaceous of South America provide mounting evidence that, at least in western Gondwana, dryolestoids developed into strongly endemic groups by the Late Cretaceous. However, the lack of pre-Late Cretaceous dryolestoid remains made study of their origin and early diversification intractable. Here we describe the first mammalian remains from the early Late Cretaceous of South America, including two partial skulls and jaws of a derived dryolestoid showing dental and cranial features unknown among any other group of Mesozoic mammals, such as single-rooted molars preceded by double-rooted premolars, combined with a very long muzzle, exceedingly long canines and evidence of highly specialized masticatory musculature. On one hand, the new mammal shares derived features of dryolestoids with forms from the Jurassic of Laurasia, whereas on the other hand, it is very specialized and highlights the endemic, diverse dryolestoid fauna from the Cretaceous of South America. Our specimens include only the second mammalian skull known for the Cretaceous of Gondwana, bridging a previous 60-million-year gap in the fossil record, and document the whole cranial morphology of a dryolestoid, revealing an unsuspected morphological and ecological diversity for non-tribosphenic mammals.     

宽带接入技术的选择

对Cable Modem、xDSL、以太网、无线局域网(WLAN)等宽带接入技术进行了分析和对比。提出了宽带接入技术的选择原则，论述了网络运营商如何结合自身特点和目标客户群的特性来选择适合自己的宽带接入技术。     

Numerical Value Results OF Guassian Beam Focussing

1Lens is placed in beam waist We consider the case of a Gaussian beam that is incident at its waist on a thin lens of focal length f.To find the location of the waist of the output beam and the beam radius at that point,we start with the ABCD law.