基于RFID技术的智能小区巡更系统开发与实现

本文针对智能小区安防系统的实际,提出一种基于RFID和GPRS技术的巡更系统。系统由巡更节点、巡更终端机及监控管理上位机构成。巡更节点采用非接触式智能卡,实现电子标签功能;巡更终端机具有节点信息读取、信息处理、无线通信功能;设计采用AT89S52作为控制器,扩展相应的外围电路,并通过GPRS无线接口与监控管理上位机进行通信。监控管理上位机具有无线接口,接收终端机发来的信息,实现远程信息监控。系统采用了最新的物联网技术,经实际运行巡更系统工作稳定,满足了智能小区安防的需要。     

弹性壁舱室噪声振动控制技术

为研究振动噪声控制技术,设计了一只以0.5 m为边长的正方体铝箱和一只以飞机内饰板为振动面的复合材料密闭空间,并采用振动激励器引起壁板振动,在箱体内产生噪声。采用在弹性壁上安装压电陶瓷换能器控制振动的方式来降低空间内的噪声。经过实际测试,大大降低了箱体内的噪声。     

超微弱信号检测在声探测系统中的应用

为了提高超微弱信号的检测能力,对声探测系统的噪声来源和特性进行了分析。根据不同的噪声特性采取了匹配、滤波、频谱累积等抑制噪声的方法,提高了系统的信噪比和探测能力。试验结果表明采取的方法有效可行。     

Effect of the codoping of N—H—O on the growth characteristics and defects of diamonds under high temperature and high pressure

Diamond crystals were synthesized with different doping proportions of N—H—O at 5.5 GPa—7.1 GPa and 1370 °C—1450 °C. With the increase in the N—H—O doping ratio, the crystal growth rate decreased, the temperature and pressure conditions required for diamond nucleation became increasingly stringent, and the diamond crystallization process was affected. [111] became the dominant plane of diamonds; surface morphology became block-like; and growth texture, stacking faults, and etch pits increased. The diamond crystals had a two-dimensional growth habit. Increasing the doping concentration also increased the amount of N that entered the diamond crystals as confirmed via Fourier transform infrared spectroscopy. However, crystal quality gradually deteriorated as verified by the red-shifting of Raman peak positions and the widening of the Raman full width at half maximum. With the increase in the doping ratio, the photoluminescence property of the diamond crystals also drastically changed. The intensity of the N vacancy center of the diamond crystals changed, and several Ni-related defect centers, such as the NE1 and NE3 centers, appeared. Diamond synthesis in N—H—O-bearing fluid provides important information for deepening our understanding of the growth characteristics of diamonds in complex systems and the formation mechanism of natural diamonds, which are almost always N-rich and full of various defect centers. Meanwhile, this study proved that the type of defect centers in diamond crystals could be regulated by controlling the N—H—O impurity contents of the synthesis system.