ZigBee无线通信技术在智能家居组网中具有重要的应用。为了探究其使用场景和方法,文章首先分析了基于ZigBee的智能家居网络组网方式,其次介绍了接收信号强度指示(Received Signal Strength Indicator,RSSI)算法的测距原理和DV-Hop算法...ZigBee无线通信技术在智能家居组网中具有重要的应用。为了探究其使用场景和方法,文章首先分析了基于ZigBee的智能家居网络组网方式,其次介绍了接收信号强度指示(Received Signal Strength Indicator,RSSI)算法的测距原理和DV-Hop算法的测点原理,最后针对两种算法的局限性,提出基于阈值的改进定位算法。展开更多
目的:基于Zigbee网络的接收信号强度指示(received signal strength indicator,RSSI)测距算法和环境传感器,设计一种能够保障工业区内工人安全的工业安全监测系统。系统功能主要包括对误入违禁区域的工人进行即时的警告、火灾险情警报...目的:基于Zigbee网络的接收信号强度指示(received signal strength indicator,RSSI)测距算法和环境传感器,设计一种能够保障工业区内工人安全的工业安全监测系统。系统功能主要包括对误入违禁区域的工人进行即时的警告、火灾险情警报、工人身体状况监测以及云平台控制系统。方法:本系统通过多节点组合获取信道模型中的环境干扰参数,采用混合滤波算法和RSSI测距算法来获取工人位置,使用传感器监测工业区内的险情和工人身体状况,运用4G DTU模块完成云平台和系统之间的控制功能。结果:实现测距功能50 m内误差低于10%,可以满足系统危险距离警报的需求,对火灾和工人身体状况实现实时监测。结论:系统可准确地对发生的灾情和进入违禁区域的工人进行实时警告同时在云平台显示,可通过手机移动端查询系统的状态和控制系统,具有方便快捷的功能。展开更多
The self-healing solid polymer electrolytes(SHSPEs)can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries(LIBs),significantly improving cycli...The self-healing solid polymer electrolytes(SHSPEs)can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries(LIBs),significantly improving cycling performance and extending service life of LIBs.Here,we report a novel cross-linked network SHSPE(PDDP)containing hydrogen bonds and dynamic disulfide bonds with excellent self-healing properties and nonflammability.The combination of hydrogen bonding between urea groups and the metathesis reaction of dynamic disulfide bonds endows PDDP with rapid self-healing capacity at 28°C without external stimulation.Furthermore,the addition of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMIMTFSI)improves the ionic conductivity(1.13×10^(−4)S cm^(−1)at 28°C)and non-flammability of PDDP.The assembled Li/PDDP/LiFePO_(4)cell exhibits excellent cycling performance with a discharge capacity of 137 mA h g^(−1)after 300 cycles at 0.2 C.More importantly,the self-healed PDDP can recover almost the same ionic conductivity and cycling performance as the original PDDP.展开更多
文摘ZigBee无线通信技术在智能家居组网中具有重要的应用。为了探究其使用场景和方法,文章首先分析了基于ZigBee的智能家居网络组网方式,其次介绍了接收信号强度指示(Received Signal Strength Indicator,RSSI)算法的测距原理和DV-Hop算法的测点原理,最后针对两种算法的局限性,提出基于阈值的改进定位算法。
基金supported by R&D Program of Power Batteries with Low Temperature and High Energy,Science and Technology Bureau of Changchun(19SS013)Key Subject Construction of Physical Chemistry of Northeast Normal University+1 种基金the Fundamental Research Funds for the Central Universities(2412020FZ007,2412020FZ008)National Natural Science Foundation of China(22102020)
文摘The self-healing solid polymer electrolytes(SHSPEs)can spontaneously eliminate mechanical damages or micro-cracks generated during the assembly or operation of lithium-ion batteries(LIBs),significantly improving cycling performance and extending service life of LIBs.Here,we report a novel cross-linked network SHSPE(PDDP)containing hydrogen bonds and dynamic disulfide bonds with excellent self-healing properties and nonflammability.The combination of hydrogen bonding between urea groups and the metathesis reaction of dynamic disulfide bonds endows PDDP with rapid self-healing capacity at 28°C without external stimulation.Furthermore,the addition of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide(EMIMTFSI)improves the ionic conductivity(1.13×10^(−4)S cm^(−1)at 28°C)and non-flammability of PDDP.The assembled Li/PDDP/LiFePO_(4)cell exhibits excellent cycling performance with a discharge capacity of 137 mA h g^(−1)after 300 cycles at 0.2 C.More importantly,the self-healed PDDP can recover almost the same ionic conductivity and cycling performance as the original PDDP.