为了解决没有移动网络信号覆盖地区的荒野工作人员遇险救援不便的问题,设计了一种基于GPS(Global Position System)/北斗卫星导航系统的野外遇险人员报警定位终端;该报警定位终端以ARM(Acorn RSIC Machine)Cortex-M4为控制核心,搭配两...为了解决没有移动网络信号覆盖地区的荒野工作人员遇险救援不便的问题,设计了一种基于GPS(Global Position System)/北斗卫星导航系统的野外遇险人员报警定位终端;该报警定位终端以ARM(Acorn RSIC Machine)Cortex-M4为控制核心,搭配两种不同颜色的LED报警闪烁灯和液晶显示屏幕,并在报警终端上设计了功率放大器电路,工作时报警终端上的GPS/北斗双模芯片精确定位人员位置信息,采用LoRa(Long Range)无线传输模块将荒野工作人员的安全信息发送至附近的固定基站或者基站车上,其一旦接收到报警信息,便可迅速作出响应,及时对遇险人员进行救援;同时,在基站上使用增益为15.5dBi的定向接收天线,并设置LoRa无线传输模块的空中速率为0.3kbps,可以使荒野工作人员的报警信息传输距离达到最远;实验结果表明,该报警终端具有实用性强、定位精度高、便于携带、工作稳定可靠,传输距离长等优点。展开更多
measurement system was designed and established to test the piezoresistive properties of resonant tunneling diodes(RTDs).The current-voltage characteristic shifts of RTD at different stress states were detected.The ex...measurement system was designed and established to test the piezoresistive properties of resonant tunneling diodes(RTDs).The current-voltage characteristic shifts of RTD at different stress states were detected.The experimental results demonstrate that the piezoresistive sensitivity of RTD is larger than 1x10−8 Pa−1.To accurately represent the piezoresistive properties of RTD,the current-voltage characteristic coherence of the same RTD was tested.According to the experimental results,the largest relative resistance shift of an RTD in the same measurement environment is less than 3%,of which 1%is caused by the testing apparatuses.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.50405025 and 50375050)the Fork Ying Tung Education Foundation(No.101052).
文摘measurement system was designed and established to test the piezoresistive properties of resonant tunneling diodes(RTDs).The current-voltage characteristic shifts of RTD at different stress states were detected.The experimental results demonstrate that the piezoresistive sensitivity of RTD is larger than 1x10−8 Pa−1.To accurately represent the piezoresistive properties of RTD,the current-voltage characteristic coherence of the same RTD was tested.According to the experimental results,the largest relative resistance shift of an RTD in the same measurement environment is less than 3%,of which 1%is caused by the testing apparatuses.
