载热体设备的热冲击和配管的热应力

对载热体设备的热冲击应力进行了计算,进而总结出防止夹套破裂的对策;通过对配管热应力的分析,得出设计热配管的要点及应对配管热膨胀的方法.     

热油泵机械密封泄漏原因及对策

冷却系统结垢后,摩擦副端面温度过高,这是导致热油泵机械密封失败的根本原因.采取软化水夹套冷却和新增静环背冷等措施,可降低摩擦副端面温度,从而解决密封泄漏的问题.     

浅析企业内部会计控制制度的完善

完整、规范的内部会计控制制度,有利于明确内部的职能分工,监督各个部门的工作成果,同时为企业所有者提供正确的会计信息,为企业的资金调配提供正确的依据。建立一套符合本企业实际的、规范的内部会计控制制度是有必要的。     

各地情报站

别克 林荫大道 拍到相片的第二天，就在网上看到了这款车的谍照。据说是别克新款凯越，但是我所看到的车型应该是属于B级车，所以请教—下，会是别克的什么车型？     

提升北京城市轨道交通一体化发展策略研究

近年来,北京城市轨道交通建设发展速度加快,对缓解交通拥堵、提升公共交通出行效率、提高交通出行的准时性起到重要作用,但在一体化方面还存在不足。通过对北京城市轨道交通一体化进行专项调查研究,选取110个轨道站点,获取线下调查样本2 400份、线上调查样本约1 000份,系统分析北京市轨道交通一体化和便利性的现状。针对调查分析结论,提出提升轨道交通一体化的对策建议:加强初始统一规划设计,优化交通枢纽布局和运营衔接,深化既有站点服务水平,推动站点接驳功能修补等。     

The Acquisition of Sand Vibration Information in Hinterland of Desert Based on Advanced Remote Sensing System and Network Technologies

The deep understanding on sand and sand dunes scale can be useful to reveal the formation mechanism of the sandstorm for early sandstorm forecast. The current sandstorm observation methods are mainly based on conventional meteorological station and satellites remote sensing, which are difficult to acquire sand scale information. A wireless sensing network is implemented in the hinterland of desert, which includes ad hoc network,sensor, global positioning system(GPS) and system integration technology. The wireless network is a three-layer architecture and daisy chain topology network, which consists of control station, master robots and slave robots.Every three robots including one master robot and its two slave robots forms an ad hoc network. Master robots directly communicate with radio base station. Information will be sent to remote information center. Data sensing system including different kinds of sensors and desert robots is developed. A desert robot is designed and implemented as unmanned probing movable nodes and sensors' carrier. A new optical fiber sensor is exploited to measure vibration of sand in particular. The whole system, which is delivered to the testing field in hinterland of desert(25 km far from base station), has been proved efficient for data acquisition.     

一种基于移动矢径的单信标测距定位算法

针对水下航行器利用移动单信标进行同步式测距定位时受初始位置误差和声速误差影响的问题,给出一种基于移动矢径的单信标同步式测距定位算法。参考移动矢径的概念建立了移动单信标测距定位模型,利用扩展卡尔曼滤波算法实现了定位滤波算法的设计。仿真和试验结果表明:本文算法可以有效减小初始位置误差带来的定位误差,并对未知声速误差进行实时估计,显著提高了水下航行器的定位精度。     

The Analysis of Angle Resolution of Stress Vector Sensor Based on Optical Fiber Sensing Cable for High Speed Railway Traffic

With the development of high speed railway traffic, the structure health monitoring for high-speed rail is necessary due to the safety issue. Optical fiber sensing technology is one of the options to solve it. Stress vector information is the important index to make more reasonable judgments about railway safety. However, information sensed by lots of commercial optical sensors is scalar. According to the stress filed distribution of rail, this paper proposes a new type of stress vector sensor based on optical fiber sensing cable (OFSC) with a symmetrical seven optical fibers structure and analyzes the relations between angle resolution and distance between adjacent of optical fibers through finite-element software (ANSYS) simulation. Through reasonable distance configuration, the angle resolution of the OFSC can be improved, and thus stress vector information, including the stress magnitude and the angle of stress, can be more accurately obtained. The simulation results are helpful to configure OFSC for angle resolution improvement in actual practice, and increase the safety factor in high speed railway structure health monitoring.     

基于虚拟仪器技术的舰船电子装备测试系统设计

现代舰船装备有高度复杂的电子系统,电子装备快速诊断是舰船保障技术的重要环节.虚拟仪表技术是计算机技术在仪器仪表领域内应用所形成的一种新型的、富有生命力的仪器种类,在工业设计与系统测试领域得到了广泛应用.文中介绍了一种基于虚拟仪器技术的舰船装备电子设备测试系统设计方案,给出了测试系统设计的原则和思路,详细论述了该测试系统的模块化软硬件设计方法.应用实践表明,该系统操作简便,分析精度高,具有很好的稳定性和通用性.     

声传播多途效应对目标方位估计影响的仿真研究

传统的目标方位估计方法基于这样一个假定,即假设信号是以平面波方式传播的,阵列的各个阵元接收到同一声源的信号波形完全相同,仅仅只是时延不同.然而在浅海环境中,由于声信号传播的多途效应使得这一假设常常不能满足.文中利用简正波理论模型分析了浅海条件下声信号传播的多途效应,并从理论上推导了浅海声传播的多途效应对传统的基于平面波假设的目标方位估计方法的影响,指出浅海声传播的多途效应会导致传统的基于平面波假设的目标方位估计方法产生方位估计偏差,在有些情况下甚至会产生主瓣的分裂,最后通过仿真试验验证了理论推导结论的正确性.