Modified white-light Mach-Zehnder interferometer for direct group-delay measurements

A modified white-light Mach-Zehnder interferometer based on a single beam splitter is described for direct group-delay measurements. The arms of the interferometer are folded in such a manner that a single beam splitter can be used to split the incoming beam and combine the outgoing beams. This method offers a twofold advantage: The measuring range of the interferometer is twice as large as that of the Michelson interferometer, and the systematic error that is associated with the beam splitter is minimized because of the configuration. We report the results of measurements on various optical components performed in the 555-630-nm spectral region and propose a scheme for the processing of the experimental data. We present a comparison of the data analyzed by the proposed processing scheme along with the theoretical calculations.     

Study of the diffusion of Al–Li alloys subjected to an electric field

An experimental investigation of the homogenization treatment of 2091 Al–Li alloy in the presence of an electric field, has revealed the phenomena of reduced volume fraction, small size, spherical shape and random distribution of second-phase particles, which bring about an increase in ductility. The results show that the dissolution of second-phase particles is promoted by means of the vacancy mechanism, because of the larger diffusion coefficient of solute atoms than the vacancy–solute complexes at the beginning of the homogenization treatment. By increasing the homogenization time and applying an electric field, the diffusion coefficient of vacancy-solute complexes is raised, whereas that of solute atoms is reduced, because of the decreased potential energy of the second phase at grain boundaries. Therefore, the non-equilibrium segregation of magnesium and copper elements is generated near the surface of the ingot by a complex mechanism. An experimental study of the solution treatment under an electric field, revealed that the lithium non-equilibrium segregation is induced at grain boundaries responsible for the precipitates. © 1998 Chapman & Hall     

Experimental study on fitness of one-piece casting osseointegrated implant frameworks with relation to fixture abutment positions

An experiment on fitness of one-piece casting osseointegrated implant frameworks was performed among three fixture abument positions where other conditions were controlled. The result revealed that there was statistically significant differences in dimensional change among the three fixture abument positions. In terms of the relation between abument position and fitness, the more backward the abument position was, the worse the osseointegrated framework fitness was. The frameworks showed deformations in "arch form" and "warp" in three dimensions.     

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.     

环境在线监测系统在大型煤炭企业中的应用

以开滦集团建设的环境在线监测系统为例,详细介绍了该系统的结构、工作原理及功能。实际应用表明,该系统可对各排污口的污染物排放情况进行实时在线监测、预警,提高了大型矿区的环境质量。     

矿用变频器功率器件选型及其驱动保护设计

分析了煤矿井下设备对变频器功率器件IGBT的需求和在IGBT选型时需要考虑的电气参数,介绍了基于2SD315模块的IGBT驱动保护电路的设计。实际应用表明,采用文中介绍的方法选用的IGBT和设计的驱动保护电路后,变频器运行稳定,IGBT驱动有效,保护完善。     

综采工作面全自动联合采煤机组的设计

为提高综采工作面的自动化水平和生产效率,提出了一种综采工作面全自动联合采煤机组的设计方案。该机组采用可视化计算机监控系统通过CAN总线控制组合开关、电牵引采煤机、液压支架、输送机、工作面沿线扩音电话及智能乳化液泵站等成套设备。实际应用表明,该机组实现了全套综采设备的远程、集中监控和管理功能。     

新一代液晶显示系统设计与实现

随着时代的演进和科技的进步,液晶显示已经在现代科技产品中得到广泛应用,为了提高液晶显示系统在带有电容触摸技术的现代电子产品中开发与应用,文章中采用新一代8位STM8S208系列MCU和ET-12864F液晶显示模块,设计了一种新型的液晶显示系统;同时介绍了STM8S208单片机的优越性和ET-12864F液晶显示模块的具体操作方法,并给出了单片机STM8S208与液晶显示模块ET-12864F构建的硬件接口电路和程序设计;经实践应用,该液晶显示系统应用开发成本低,效率高具有较好的项目应用参考价值。     

基于ZigBee技术的建筑能耗监测系统设计

随着我国建筑总量不断攀升,建筑能耗也逐年增加,更加有效地实施建筑能耗统计及建筑节能管理具有重要的意义;通过对建筑能耗监测系统的分析,在研究ZigBee技术的基础上,提出了基于ZigBee无线传感器网络的建筑能耗监测系统总体结构,对其网络拓扑控制和路由协议进行了研究,并介绍了系统周期性工作过程;网络测试表明,该系统可靠性好,能够实现建筑能耗数据的采集和无线传输;通过对能耗数据的统计分析,为降低建筑能耗和提高建筑能效,提供了决策依据和参考.     

基于FPGA的某雷达多功能数字替换板设计

为了提高高技术战争条件下电子装备战场抢修的快捷性、时效性,减少备件携带数量,以某雷达火控计算机中4块数字电路板为背景设计了一种多功能替换版;该替换版以一块FPGA芯片为控制核心,并配以海绵电路区和跳线插座的设计,使得在战场紧急情况下只需更换EPROM存储芯片,并在海绵电路区上焊接相应的集成电路器件以及调整跳线插座来控制信号走向,就可以在短时间内方便快捷地对损坏电路板实施替换;结果证实,该技术可作为一种备用的维修手段,可以在很大程度上提高部队装备战场维修率.