We investigate the beam focusing technology of shear-vertical(SV) waves for a contact-type linear phased array to overcome the shortcomings of conventional wedge transducer arrays. The numerical simulation reveals the...We investigate the beam focusing technology of shear-vertical(SV) waves for a contact-type linear phased array to overcome the shortcomings of conventional wedge transducer arrays. The numerical simulation reveals the transient excitation and propagation characteristics of SV waves. It is found that the element size plays an important role in determining the transient radiation directivity of SV waves. The transient beam focusing characteristics of SV waves for various array parameters are deeply studied. It is particularly interesting to see that smaller element width will provide the focused beam of SV waves with higher quality, while larger element width may result in erratic fluctuation of focusing energy around the focal point. There exists a specific range of inter-element spacing for optimum focusing performance. Moreover, good beam focusing performance of SV waves can be achieved only at high steering angles.展开更多
供电设备集中监控告警系统要采用消息队列的方法处理监控数据,数据存储较为杂乱,导致系统性能较差。因此,提出分布式接触网供电设备集中监控告警系统设计。在系统的硬件设计上,以DSP控制芯片为核心,结合基站收发信台与供电设备进行通信...供电设备集中监控告警系统要采用消息队列的方法处理监控数据,数据存储较为杂乱,导致系统性能较差。因此,提出分布式接触网供电设备集中监控告警系统设计。在系统的硬件设计上,以DSP控制芯片为核心,结合基站收发信台与供电设备进行通信连接。在系统的软件设计上,基于供电设备数据流字段,采用拓扑数据库的形式进行数据存储,分析拓扑关系建立数据监控拓扑布局,建立告警索引表实现供电设备集中监控告警的系统功能。测试该系统进行性能,结果表明系统通信损耗均比较低,损耗均值仅为0.35 d B,可以有效集中监控和告警供电设备。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11774377 and 11574343)。
文摘We investigate the beam focusing technology of shear-vertical(SV) waves for a contact-type linear phased array to overcome the shortcomings of conventional wedge transducer arrays. The numerical simulation reveals the transient excitation and propagation characteristics of SV waves. It is found that the element size plays an important role in determining the transient radiation directivity of SV waves. The transient beam focusing characteristics of SV waves for various array parameters are deeply studied. It is particularly interesting to see that smaller element width will provide the focused beam of SV waves with higher quality, while larger element width may result in erratic fluctuation of focusing energy around the focal point. There exists a specific range of inter-element spacing for optimum focusing performance. Moreover, good beam focusing performance of SV waves can be achieved only at high steering angles.
文摘供电设备集中监控告警系统要采用消息队列的方法处理监控数据,数据存储较为杂乱,导致系统性能较差。因此,提出分布式接触网供电设备集中监控告警系统设计。在系统的硬件设计上,以DSP控制芯片为核心,结合基站收发信台与供电设备进行通信连接。在系统的软件设计上,基于供电设备数据流字段,采用拓扑数据库的形式进行数据存储,分析拓扑关系建立数据监控拓扑布局,建立告警索引表实现供电设备集中监控告警的系统功能。测试该系统进行性能,结果表明系统通信损耗均比较低,损耗均值仅为0.35 d B,可以有效集中监控和告警供电设备。
