Robust Flexible Textile Tribovoltaic Nanogenerator via a 2D 2H-MoS2/Ta4C3 Dynamic Heterojunction

The tribovoltaic effect can convert semiconductor interfacial frictional mechanical energy into direct current (DC) electricity, but the flexibility and durability of semiconductor materials limit its application in wearable electronic. Herein, a robust flexible textile tribovoltaic nanogenerator is presented based on a 2D dynamic heterojunction of 2H-MoS₂/Ta₄C₃ (MTNG). During the friction process, a built-in electric field (E_b) and an additional interfacial electric field (E_CE) are generated in a continuous dynamic contact of 2H-MoS₂/Ta₄C₃, and through the 2H-MoS₂/Ta₄C₃ dynamic heterojunction, a significant number of electron-hole pairs are excited and move directionally to generate a DC. The influences of mechanical pressure and sliding speed on output performance of MTNGs are systematically investigated. The MTNGs deliver excellent output power density (39.15 mW m²) and outstanding robustness (43 000 cycles). Ten MTNGs can be connected in series to obtain a DC voltage of 3.3 V and in parallel to obtain a DC current of 75 µA. Furthermore, the MTNGs can effectively power a variety of commercial electronic watches and calculators by harvesting human kinetic energy. A 2D dynamic heterojunction 2H-MoS₂/Ta₄C₃ DC nanogenerator is described and offers a workable option for the creation of flexible DC power sources and self-powered wearable electronics.     

基于分簇的无线传感器网络安全路由协议研究

无线传感器网络（Wireless Sensor Networks,简称WSNs）作为一种新的获取信息的方式和处理模式,已成为通信领域的研究重点。而路由协议则是无线传感器网络当前的热点研究之一。目前,针对较为典型的分簇式路由协议LEACH路由协议的研究,是无线传感器网络目前研究的一个热点。介绍了无线传感器网络路由协议常见的攻击类型,并从路由安全的角度建议性的提出了一种对LEACH路由协议针对安全性的改进方案,并应用NS2仿真平台,对改进协议做了仿真并进行了性能分析。     

支持移动多媒体通信中间件的WAP网关

WAP协议是WAP论坛提出的一个开放通信协议;WAP网关进行协议的转换,是移动终端无线接入Internet的枢纽。在简要介绍了无线应用协议后,提出了一个在Linux操作系统平台下运行的WAP网关(数据通信网关)的设计与实现方案,该WAP网关由承载层模块、WAP模块和SMS模块组成,其中详细介绍承载层模块和WAP模块的工作原理,并在实验室环境下对网关进行测试,给出了测试结果。     

相干光通信中的光学桥接器

相干光通信技术是提高接收机灵敏度,发展大容量高码率激光通信系统的重要技术手段,光学桥接器将信号激光和本振激光链接到光电探测器进行相干探测处理,是相干光通信系统的关键器件之一.对近20多年来发展的光学桥接器进行了总结和分类,介绍了不同光学桥接器的原理、构造和性能,分析了光学桥接器的关键技术.     

Depth video spatial and temporal correlation enhancement algorithm based on just noticeable rendering distortion model

Spatial and temporal inconsistency of depth video deteriorates encoding efficiency in three dimensional video systems. A depth video processing algorithm based on human perception is presented. Firstly, a just noticeable rendering distortion (JNRD) model is formulated by combining the analyses of the influence of depth distortion on virtual view rendering with human visual perception characteristics. Then, depth video is processed based on the JNRD model from two aspects, spatial and temporal correlation enhancement. During the process of spatial correlation enhancement, depth video is segmented into edge, foreground, and background regions, and smoothened by Gaussian and mean filters. The operations of the temporal correlation enhancement include temporal–spatial transpose (TST), temporal smoothing filter and inverse TST. Finally, encoding and virtual view rendering experiments are conducted to evaluate the proposed algorithm. Experimental results show that the proposed algorithm can greatly reduce the bit rate while it maintains the quality of virtual view.     

基于最大流的无线mesh网络负载均衡信道分配算法

针对无线mesh网络中各信道间的干扰情况及流量负载均衡问题,定义了负载均衡的目标优化函数,设计一种基于最大流的负载均衡信道分配算法。该算法优先考虑为负载量比较大的链路分配更多的带宽,使得一些关键链路能够承受较大的流量负载,实现各信道的负载均衡,减少网络拥塞,降低分组丢失率和延迟。实验结果表明,该算法较好地平衡了网络负载,在网络业务较重的情况下还能获得较好的网络性能。     

Optimal energy efficiency routing strategy based on community in mobile social network

An optimal energy efficiency routing strategy based on community was proposed,which minimized the network energy consumption under the given delay constraint.Firstly the expected energy consumption and delay of message delivery in the connected network were obtained through Markov chain.Then the comprehensive cost function for delivering message from source node to destination node was designed,which was combined with energy consumption and delay.Thus,the optimization function to comprehensive cost of relay node delivering message was obtained,and further the reward function of relay node was gotten.Finally the optimal expected reward of optimal relay node was achieved using the optimal stopping theory,so as to realize the optimal energy efficiency routing strategy.In simulations,the average energy consumption,the average delay and the average delivery ratio of routing optimization strategy were compared with those of other routing strategies in related literatures.The results show that the strategy proposed has smaller average energy consumption,shorter average delay and higher average delivery ratio,gaining better energy consumption optimization effect.     

智能电视信号监测报警器的设计

基于高性能的MEGA2560单片机,设计了一款智能电视信号监测报警记录器.该报警器采用TA7666P和延时电路实现音频信号监测,采用MAX7452实现视频信号监测,采用检波器和A/D转换器相结合的形式完成电视发射机功率信号的监测.该系统的电路结构简单,性能可靠,能满足广播电视系统的信号监测需要.     

TMWSNs中一种确保数据完整性的高能效时空Top-k查询协议

时空Top-k查询是TMWSNs（双层移动无线传感网）中的一类重要查询.在敌对环境中,攻击者易通过捕获TMWSNs中的关键节点来破坏时空Top-k查询的数据完整性.提出一种确保数据完整性的时空Top-k查询处理协议VIP-TQ.该协议利用虚拟化节点技术与绑定加密技术通过构建传感器节点的数据预处理方法、数据存储节点的时空Top-k查询处理方法以及Sink端的数据完整性验证方法来实现TMWSNs中时空Top-k查询的数据完整性保护.理论分析和实验结果显示,VIP-TQ能够以100%的概率侦测出不完整的时空Top-k查询结果,并具有相对已有方案更高的能效性.     

Low voltage and time constant organic synapse-transistor

We report on an artificial synapse, an organic synapse-transistor (synapstor) working at 1 V and with a typical response time in the range 100–200 ms. This device (also called NOMFET, Nanoparticle Organic Memory Field Effect Transistor) combines a memory and a transistor effect in a single device. We demonstrate that short-term plasticity (STP), a typical synaptic behavior, is observed when stimulating the device with input spikes of 1 V. Both significant facilitating and depressing behaviors of this artificial synapse are observed with a relative amplitude of about 50% and a dynamic response <200 ms. From a series of in-situ experiments, i.e. measuring the current–voltage characteristic curves in-situ and in real time, during the growth of the pentacene over a network of gold nanoparticles, we elucidate these results by analyzing the relationship between the organic film morphology and the transport properties. This synapstor works at a low energy of about 2 nJ/spike. We discuss the implications of these results for the development of neuro-inspired computing architectures and interfacing with biological neurons.