Ultrafast measurement of transient electroosmotic flow in microfluidics

We present a non-intrusive molecular dye based method, i.e., laser-induced fluorescence photobleaching anemometer (LIFPA), to significantly increase temporal resolution (TR) for velocity measurement of fast transient electrokinetic flows. To our knowledge, the TR has been for the first time achieved to 5–10 μs, about 100 times better than that published from state-of-the-art micro particle image velocimetry (μPIV), which is currently the most widely used velocimetry in the microfluidics community. The new method provides us with new opportunities to study experimentally the fundamental phenomena of unsteady electrokinetics (EK) and to validate relevant theoretical models. One application of the new method is demonstrated by measuring the rise time of DC electroosmotic flows (EOFs) in a microcapillary of 10 μm in diameter.     

基于激光超声表面波检测的瓦斯检测研究

利用SnO2/Pt气敏薄膜对瓦斯气体的选择性吸附作用将引起声表面波在其表面的传播速度发生相应改变的性质,并结合激光超声检测技术,提出了一种新的瓦斯检测方法.采用激光在覆有选择性气体吸附薄膜的抛光铝材表面激发出声表面波,用单芯光纤耦合的反射式光束偏转法对所激发声表面波信息进行采集,进而通过合理的算法可以准确检测出环境中瓦斯气体的体积分数.为瓦斯监测方法提供了一种新途径.     

Dynamically modulated intensity interrogation scheme using waveguide coupled surface plasmon resonance sensors

An electro-optically modulated intensity interrogation method based on tunable waveguide coupled surface plasmon resonance sensors has been proposed. It has been theoretically and experimentally demonstrated that the proposed scheme can enable sensitive measurement of measurand variations. By modulating the refractive index in the waveguide layer, this interrogation method yields modulated signal whose amplitude is related to measurand's refractive index. This amplitude modulated signal offers a higher signal to noise ratio and eliminates additive noise in the sensor system. A preliminary investigation using saline buffers with different NaCl concentrations shows a resolution of 2.3 × 10^?6 refractive index unit by our approach. Resolution can be controlled by the amplitude of the applied modulation voltage and can be further enhanced by optimizing the device structure or improving the electro-optical (E-O) coefficient of the E-O material. This approach is simple, stable, and promising for low-cost or multi-channel SPR biosensor applications.     

基于事件驱动的动态免疫分簇路由算法*

为了降低应用于突发事件监测的无线传感器网络的能量消耗,设计实现了一种基于事件驱动的动态免疫分簇路由算法。将生物免疫系统的工作机制应用到无线传感器网络事件驱动的动态分簇算法中,事件作为抗原,传感器节点作为抗体,抗体对抗原有记忆保存的功能,使得相似的抗原再次出现时对事件及时响应。相似事件再次发生且传感器节点符合能量要求时,可以直接调用抗体中的记忆,对事件进行快速建簇,节省了簇的建立过程所消耗的大量能量,增加了网络的数据传输量,延长了网络的生命周期。仿真结果表明,生物免疫机制的学习记忆特性可以有效提高事件驱动的动态分簇算法的网络性能。     

智能电源系统在信号领域中的应用

随着轨道交通的发展,信号设备要求具备智能化、模块化、自动化、网络化的智能电源系统。针对信号系统的发展对智能电源系统的要求,阐述了智能电源系统在智能化、模块化、自动化三方面的应用。介绍了目前智能电源系统所采用各种不同的技术方案,并论述了方案的优缺点,总结了目前存在的问题和发展方向。     

数据库推理通道的动态控制

数据库推理问题是数据库安全研究的重要组成部分,主要研究推理通道的检测方法和控制策略。该文提出一种动态控制推理通道的方法。该方法为每个推理通道建立一个标识集合,利用集合中元素和推理通道中对象的关联来控制查询的处理,使用户能灵活地访问数据但又得不到足够的信息来推理。与以前提出的方案不同,该方案保证了数据的最大可用性,同时有效地阻止推理并保持了快速的查询处理能力。     

基于VB的INTERBUS OPC通讯应用研究

OPC作为一种有效的设备间信息数据传输方式,在工业控制领域已经得到了广泛的应用。本文提出应用OPC的通信方式,在INTERBUS控制系统中,实现其现场控制站与VB操作员站之间的数据传输,从而实现对整个系统的监控和管理。     

大气污染控制工程立体化教学模式建构

介绍了大气污染控制工程课程教学改革研究的内容,提出了由教学内容、教学形式、教学平台与教学评价等4方面组成的立体化课程教学模式,并讨论了该模式下教学资源平台的建设,给出了大气污染控制工程课程的评价和考核方法.该模式在实践教学中取得了比较好的成效.     

Stress wave propagation in supporting bolts: A test for bolt support quality

A test method for the non-destructive determination of bolt length, anchoring length, and bolt body force is described. This addresses the problems of low accuracy, limited number of data, and untimely warning signs encountered with existing test methods. Numerical simulations of the bolt, resin, and rock system show that the length accuracy when using the velocity wave is lower than when using the acceleration wave. It is accepted practice to use the acceleration wave for length tests because of improved signal to noise ratios of the waveforms. Laboratory and in situ underground tests showed that the precision of the measurements meets field requirements. Using this method the anchor properties of each single bolt and, thus, the safety of the entire roadway support may be evaluated.