校园位置服务(Location Based Service,LBS)平台已成为信息交流测试和位置获取实验性能评价的重要手段。作者在移动互联网下建立校园LBS模型,引入系统级设计方法,采用精确定位技术,设计并实现了用于移动互联网下的校园位置服务(Campus L...校园位置服务(Location Based Service,LBS)平台已成为信息交流测试和位置获取实验性能评价的重要手段。作者在移动互联网下建立校园LBS模型,引入系统级设计方法,采用精确定位技术,设计并实现了用于移动互联网下的校园位置服务(Campus Location Based Service Platform,CLBSP);该平台实现了输入、输出排队、联合交叉排队等的高度集成;最后给出了基于该平台不同LBS模型下的性能测试结果,与输入、输出排队信息交流测试进行比较,显示了良好的性能,验证了校园LBS平台的合理性。展开更多
We study here effects of nozzle layout on the droplet ejection of a micro atomizer, which was fabricated with the arrayed nozzles by the MEMS technology and actuated by a piezoelectric disc. A theoretical model was fi...We study here effects of nozzle layout on the droplet ejection of a micro atomizer, which was fabricated with the arrayed nozzles by the MEMS technology and actuated by a piezoelectric disc. A theoretical model was first built for this piezoelectric-liquid-structure coupling system to characterize the acoustic wave propagation in the liquid chamber, which determined the droplet formation out of nozzles. The modal analysis was carried out numerically to predict resonant frequencies and simulate the corresponding pressure wave field. By comparing the amplitude contours of pressure wave on the liquid-solid interface at nozzle inlets with the designed nozzle layout, behaviors of the device under different vibration modes can be predicted. Experimentally, an impedance analyzer was used to measure the resonant frequencies of the system. Three types of atomizers with different nozzle layouts were fabricated for measuring the effect of nozzle distribution on the ejection performance. The visualization experiment of droplet generation was carried out and volume flow rates of these devices were measured. The good agreement between the experiment and the prediction proved that only the increase of nozzles may not enhance the droplet generation and a design of nozzle distribution from a view-point of frequency is necessary for a resonant related atomizer.展开更多
文摘校园位置服务(Location Based Service,LBS)平台已成为信息交流测试和位置获取实验性能评价的重要手段。作者在移动互联网下建立校园LBS模型,引入系统级设计方法,采用精确定位技术,设计并实现了用于移动互联网下的校园位置服务(Campus Location Based Service Platform,CLBSP);该平台实现了输入、输出排队、联合交叉排队等的高度集成;最后给出了基于该平台不同LBS模型下的性能测试结果,与输入、输出排队信息交流测试进行比较,显示了良好的性能,验证了校园LBS平台的合理性。
基金the National Natural Science Foundation of China(50405001).
文摘We study here effects of nozzle layout on the droplet ejection of a micro atomizer, which was fabricated with the arrayed nozzles by the MEMS technology and actuated by a piezoelectric disc. A theoretical model was first built for this piezoelectric-liquid-structure coupling system to characterize the acoustic wave propagation in the liquid chamber, which determined the droplet formation out of nozzles. The modal analysis was carried out numerically to predict resonant frequencies and simulate the corresponding pressure wave field. By comparing the amplitude contours of pressure wave on the liquid-solid interface at nozzle inlets with the designed nozzle layout, behaviors of the device under different vibration modes can be predicted. Experimentally, an impedance analyzer was used to measure the resonant frequencies of the system. Three types of atomizers with different nozzle layouts were fabricated for measuring the effect of nozzle distribution on the ejection performance. The visualization experiment of droplet generation was carried out and volume flow rates of these devices were measured. The good agreement between the experiment and the prediction proved that only the increase of nozzles may not enhance the droplet generation and a design of nozzle distribution from a view-point of frequency is necessary for a resonant related atomizer.
