ARM和ZigBee的智能家居监控网络设计

提出了一种智能家居监控网络系统,该系统以ARM微处理器S3C2440为核心,采用浏览器/服务器和客户端/服务器模式,对外通过Internet局域网和无线局域网接入公共网络,在家庭内部通过基于德州仪器C2530无线收发芯片的ZigBee无线网络将家用电器与其他监控设备连接在一起组成无线家庭网络;通过Windows客户端或Web浏览器可以对家庭内部或家用电器进行状态查询和控制,在户内可以使用手持设备,基于Android系统客户端对家用电器进行控制和管理;实际测试结果表明,系统组网方便快捷、运行稳定可靠,能够达到智能家居系统的一般应用要求。     

基于MQTT协议的在线离子色谱仪远程监控系统设计

在线离子色谱仪是可以对样品进行连续自动分析,并以谱图的形式显示样品中离子含量的化学分析仪器。为确保对样品的连续检测,仪器需要不间断的运行。由于设备经常放在工作室或偏远地区,需要对在线离子色谱仪的运行状况进行远程监控。针对此问题设计在线离子色谱仪的远程监控系统。该系统使用轻量级MQTT协议作为通讯协议,通过在线离子色谱仪中集成MQTT客户端,在云服务器中部署MQTT的消息中间件和短信网关,实现了用户在手机应用客户端查看在线离子色谱仪的运行参数、通过手机短信接收紧急报警信息等功能。     

基于RTP/RTCP的塔机远程实时监控系统设计与实现

塔机远程安全监控模型容易受到电缆线或无线电信号的限制,大大降低塔机信号传递距离和质量,导致传统的塔机监控模型信号仅能传递几十米到几百米,无法实现塔机的远程实时监控,设计并实现了一种基于RTP/RTCP的智能塔机远程实时监控系统,采用基于C/S与B/S结合的数据链驱动无缝集成模式,设计了智能塔机远程监控模型,实现了各模块间的网络传递,主要包括嵌入式监控终端、中心服务器以及远程客户端3个模块,对中心服务器和客户端采用RTP/RTCP实现视频传递,设计了基于Ajax的Web交互式人机界面,对大规模网络数据进行实时处理分析,最终完成了塔机远程实时视频传输的过程;实验结果说明,所设计模型能够实现塔机的远程实时智能监控,具有较高的监控效率和精度。     

基于B/S架构的嵌入式远程用电管理系统

针对校园中现有用电管理系统的存在的缺陷与弊端,提出了一种基于B/S架构的嵌入式远程用电管理系统的解决方案。系统以ARM-CORTEX-A8为主控板的核心处理器,Linux操作系统为应用程序的运行环境,同时在Linux系统中搭建了嵌入式BOA服务器。系统中使用html语言完成系统与用户的交互页面,并通过CGI技术实现了浏览器与嵌入式服务器的数据交互。为不改变原有建筑电力布线,系统终端采用zigbee无线网络实现远程的用电监控,从而实现远程用电管理系统。为使系统运行效率高,主进程中使用多线程技术完成系统中各任务,系统中使用数据共享内存的方式完成各进程间的数据通信,使用消息队列实现客户端对系统终端设备的控制,系统中通过sqlite3数据库完成所有历史数据的记载。通过系统实验测试,该系统可以正确响应用户需求以及满足校园内所设置的合理用电申请的远程用电管理要求,在安全、节约用电的同时有最大程度的方便了校园内非常规工作需求。     

基于ZigBee和Android的家用移动监护系统设计与实现

为解决传统家用监护系统成本高、移动性差、布线困难等问题,设计并实现了一种基于ZigBee和Android技术的家用移动监护系统;系统采用分层的体系结构,第一层为检测终端,以STM32微处理器为核心,包含多个生理信息采集节点;第二层为家庭网关,包括ZigBee主节点和计算机服务器,通过ZigBee无线组网技术完成服务器与检测终端的网络通信;第三层为Android移动平台,通过外部网络访问服务器,提供远程交互平台;该系统应用于老年人的家庭健康监护,对体温和血压两项重要生理指标进行测量;实验表明,该系统通信质量良好,能够实现生理信号的采集、传输和波形显示,以及血压值、体温值的分析和高危报警,满足了家用移动监护的要求。     

基于GPRS和ZigBee的节能型LED路灯智能控制系统

针对现有城市路灯控制系统路灯使用寿命短、无法远程操控、不能自动识别故障路灯的问题,提出一种基于GPRS网络技术和ZigBee无线通信技术的节能型LED路灯智能控制系统,使用ZigBee无线网络与LED路灯控制终端通信,并通过GPRS通讯模块接入GPRS网络与远程控制中心相连,实现远程控制LED路灯,此外,通过LED路灯控制终端实时采集路灯电压和电流,实现LED路灯的远程监控。具体阐述了GPRS通讯模块、ZigBee无线网络模块、LED控制终端的硬件设计方案,软件设计流程,系统通信协议和远程控制实现方法。测试结果证明此系统数据传输可靠、响应及时、成本低、易于实现LED路灯的远程控制和远程监控,具有较大的实用性和推广价值。     

基于B/S结构的分布式风电监控系统设计

为解决风力发电系统分布不集中,各品牌的风力发电系统的监控设备不统一的问题,开发了一种基于B/S结构的风力发电监控系统。系统采用三层B/S软件架构思想,由客户端浏览器、Web服务器端以及数据库服务器组成。利用ASP.NET技术实现对风电现场的实时监控和利用小波神经网络实现对风机的故障诊断等功能。该监控系统具备跨平台运行能力,降低了监控系统对客户端的要求,对不同风电现场具有整合监控能力,同时该监控系统诊断功能能提高风机维护针对性,有效的减少维护时间。     

基于ZigBee的公交IC卡实名制系统设计

随着物联网技术的发展,设计一种公交IC卡实名制系统已经成为一种可能;在此基础上提出一种基于ZigBee的公交IC卡实名制系统设计方案;该设计方案采用新一代SOC芯片CC2530作为整个系统ZigBee节点主控芯片,多个ZigBee节点构成拓扑网络收集IC卡信息,每个子网最终通过ZigBee协调器和GPRS构成的网关连接远程数据库,实时更新数据库信息;通过C/S客户端管理IC卡,实现公交IC卡实名制;文章方案也可以进行二次开发,加入公交车位置、公交车传感器数据等信息;测试表明,远程数据库中IC卡信息能够准确更新,具有很强的实用价值。     

基于ZigBee与Android的边境安防系统研究

结合ZigBee技术,设计了一种低成本、易安装的边境安防系统;在以cc2530为核心的ZigBee节点上搭载震动传感器与CMOS传感器提供报警与图像采集功能,通过ZigBee网络、搭载Android系统的ARM控制板将图片信息通过3G网络上传至服务器,由PC端的客户端软件监听、查看图片信息,完成对指定区域的远程监控;介绍了系统各部分的硬件设计与软件实现,最后给出了整套系统的测试效果;实验结果表明,搭载CMOS传感器的ZigBee安防系统能满足边境环境下的安防系统要求。     

基于3G网络和CAN总线的汽车远程控制系统设计

针对传统汽车远程控制系统时延高、安全性差等问题,提出了新的远程控制方案,实现了远程服务器通过车载控制终端对车载网络中各节点设备的远程控制;在远程服务器与车载控制终端通信过程中采用3G网络、TCP协议和AES加密,降低了系统的通信时延,提高了系统的可靠性和安全性;车载控制终端与各节点设备采用CAN总线网络进行通信,实现了对各节点的有效控制;经过测试,系统能很好地满足远程服务器对车门窗、车灯、报警器和发动机等节点设备远程控制时延和安全性的要求,各节点响应快,可靠性高,具有较强的实时性和良好的扩展性。     

基于STM32F的企业楼宇节能控制系统设计

针对企业楼宇耗电量严重的问题,研究设计了基于STM32F的楼宇节能控制系统。该系统采用红外传感模块统计楼宇内人数,使用光控模块采集光照度,通过微处理器实时采集人数和光照强度信号,然后进行数据处理和算法分析,从而实现楼宇照明灯具的自动控制;同时采集用电电器的工作状态信息,若电器长时间处于待机状态,系统将会自动切断其供电电源。实验结果表明：企业楼宇节能控制系统提高了电能利用率,实现了楼宇的低碳节能。     

太阳能无线输电演示仪的研制

应用电磁学理论以及电子技术自制了一套太阳能无线输电演示实验仪。该演示仪由太阳能进行供电,利用电磁耦合共振技术,实现了电能的无线传输。通过增加数码管电压-电流显示电路,可以定量显示电能传输随距离变化的效果,能精确而直观地演示电能无线传输的物理现象。该仪器结构简单、性能稳定、操作方便,可广泛用于课堂演示、课程设计等目的,在实际应用中取得了良好的教学效果。     

低品位热能有机朗肯循环发电技术进展

有机朗肯循环发电技术是基于有机朗肯循环(Organic Rankine Cycle,ORC),利用低沸点有机工质,将低品位的余热资源转换为高品位的电能的先进技术,能够有效提高能源的利用率,减少能源损失.针对工业过程中大量中低温余热受到各种限制难以回收利用难题,全面综述了有机工质朗肯循环低温余热发电技术现状和进展,具体包...     

Electron tunneling through double-electric barriers on HgTe/CdTe heterostructure interface

We investigate theoretically the carrier transport in a two-dimensional topological insulator of (001) HgTe/CdTe quantum-well heterostructure with inverted band, and find distinct switchable features of the transmission spectra in the topological edge states by designing the double-electric modulation potentials. The transmission spectra exhibit the significant Fabry-Pérot resonances for the double-electric transport system. Furthermore, the transmission properties show rich behaviors when the Fermi energy lies in the different locations in the energy spectrum and the double-electric barrier regions. The opacity and transparency of the double-modulated barrier regions can be controlled by tuning the modulated potentials, Fermi energy and the length of modulated regions. This electrical switching behavior can be realized by tuning the voltages applied on the metal gates. The Fabry-Pérot resonances leads to oscillations in the transmission which can be observed in experimentally. This electric modulated-mechanism provides us a realistic way to switch the transmission in edge states which can be constructed in low-power information processing devices.     

异质结界面电荷对突变InP/InGaAs异质结双极晶体管热场发射影响研究

异质结界面电荷的存在改变了异质结的内建势, 这引起了界面势垒尖峰高度和形状的扰动, 从而使异质结界面载流子的输运产生相应的变化, 最终导致异质结双极晶体管 (HBT) 性能的改变. 基于热场发射-扩散模型, 对异质结界面电荷对InP/InGaAs HBT性能的改变做了研究, 得到结论是正极性的界面电荷有利于InP/InGaAs HBT的直流和高频特性的改善, 而负极性的界面电荷则使器件的直流和高频特性变差. 关键词： InP/InGaAs异质结双极晶体管 界面电荷 内建势 热场发射     

Investigating the acoustics of a sample of open plan and enclosed Kindergarten classrooms in Australia

Open plan classrooms, where several class bases share the same space, have recently re-emerged in Australian primary schools. This study compared the acoustics of four different Kindergarten classrooms: an enclosed classroom with 25 students, a double classroom with 44 students, a linear fully open plan triple classroom with 91 students, and a semi-open plan K-6 classroom with 205 students. Ambient noise levels, intrusive noise levels, occupied background noise levels, and teacher’s speech levels were recorded during different activities. Room impulse responses using logarithmic sweeps were also recorded for different teaching scenarios. From these recordings, signal-to-noise ratios, speech transmission index scores, and reverberation times were calculated. The results revealed much higher intrusive noise levels in the two largest open plan classrooms, resulting in signal-to-noise ratios and speech transmission index scores to be well below those recommended in classrooms with students of this age. Additionally, occupied background noise levels in all classrooms were well above recommended levels. These results suggest noise in classrooms needs to be better controlled, and open plan classrooms are unlikely to be appropriate learning environments for young children due to their high intrusive noise levels. The impact of noise on children’s learning and teacher’s vocal health are discussed.     

New device architecture of a thermoelectric energy conversion for recovering low-quality heat

Low-quality heat is generally discarded for economic reasons; a low-cost energy conversion device considering price per watt, $/W, is required to recover this waste heat. Thin-film based thermoelectric devices could be a superior alternative for this purpose, based on their low material consumption; however, power generated in conventional thermoelectric device architecture is negligible due to the small temperature drop across the thin film. To overcome this challenge, we propose new device architecture, and demonstrate approximately 60 Kelvin temperature differences using a thick polymer nanocomposite. The temperature differences were achieved by separating the thermal path from the electrical path; whereas in conventional device architecture, both electrical charges and thermal energy share same path. We also applied this device to harvest body heat and confirmed its usability as an energy conversion device for recovering low-quality heat.     

External and internal noise surveys of London primary schools

Internal and external noise surveys have been carried out around schools in London, UK, to provide information on typical levels and sources to which children are exposed while at school. Noise levels were measured outside 142 schools, in areas away from flight paths into major airports. Here 86% of the schools surveyed were exposed to noise from road traffic, the average external noise level outside a school being 57 dB L(Aeq). Detailed internal noise surveys have been carried out in 140 classrooms in 16 schools, together with classroom observations. It was found that noise levels inside classrooms depend upon the activities in which the children are engaged, with a difference of 20 dB L(Aeq) between the "quietest" and "noisiest" activities. The average background noise level in classrooms exceeds the level recommended in current standards. The number of children in the classroom was found to affect noise levels. External noise influenced internal noise levels only when children were engaged in the quietest classroom activities. The effects of the age of the school buildings and types of window upon internal noise were examined but results were inconclusive.     

Tunable localized surface plasmon resonances in one-dimensional h-BN/graphene/h-BN quantum-well structure

The graphene/hexagonal boron-nitride(h-BN) hybrid structure has emerged to extend the performance of graphenebased devices. Here, we investigate the tunable plasmon in one-dimensional h-BN/graphene/h-BN quantum-well structures.The analysis of optical response and field enhancement demonstrates that these systems exhibit a distinct quantum confinement effect for the collective oscillations. The intensity and frequency of the plasmon can be controlled by the barrier width and electrical doping. Moreover, the electron doping and the hole doping lead to very different results due to the asymmetric energy band. This graphene/h-BN hybrid structure may pave the way for future optoelectronic devices.     

基于DSP的航空电源BIT系统研究与设计

随着航空技术的发展,大量机载设备特别是航空仪器仪表与传动系统采用电能驱动,航空电源在现代飞行器中的作用愈发重要。作为飞机发电机与机载用电设备之间的电力枢纽,飞机二次电源的可靠性对于维持用电设备的稳定运行具有重要的意义。应用BIT技术可以实现对飞机二次电源运行状态的实时监控,然而虚警问题对BIT技术的应用造成了很大的困扰。针对某型飞机二次电源采用合理的硬件设计结合有效的检测算法可以显著改善BIT系统的虚警率,这就使操作人员能够准确掌握飞机二次电源的工作状态,及时的发现问题、减少损失。