基于LPC2294的无线监控系统设计

设计了一种基于ARM/GPRS的远程无线监控系统,该系统采用ARM7TDMI-S处理器,嵌入式实时操作系统μC/OS-Ⅱ作为系统运行平台,通过485总线将现场数据采集至监控终端,使用GPRS模块实现了数据监控终端与上位监控终端的远程实时通讯.     

嵌入式安防远程监控系统的设计

针对家居安全环境的重要性,介绍了基于嵌入式的无线远程安防监控系统的硬件结构和软件程序设计。系统以ARM11为开发平台,在嵌入式Linux的开发环境中嵌入了Web服务器、SQL数据库,以及WiFi模块驱动程序;引入了GPRS和WiFi两种无线监控方法,实时传送系统监控信息。用户通过手机短信或远程PC机登录嵌入式Web服务器的监控界面,就能实现对家居环境的监测和控制。     

基于STM32微控制器的无线水塔远程监控系统

针对目前农村集中供水实时监控自动化水平低下、人力成本较高和施工布线繁重的问题,提出基于STM32微控制器的无线水塔远程监控解决方案。根据方案进行了系统硬件和软件设计。系统以STM32F103RC微控制器作为下位机控制核心,通过Keil u Vision3集成开发环境,采用C语言设计了智能数据采集终端和智能网关MCU应用软件,实现了现场多个水塔水位信息的实时采集和水泵实时控制。整个系统采用PC机作为上位机监控中心,基于Lab VIEW 2012开发环境进行上位机监控中心数据管理软件开发,实现向下位机发送监控命令,同时对现场多个数据采集终端的采样数据进行存储、处理、显示及统计等功能。     

基于LabVIEW与PLC的水源地无线远程监控系统设计

提出了一种基于LabVIEW的无线远程监控系统的设计,来满足水源地需要人工现场控制及分散管理的需求.采用Modbus协议,通过RS485总线实现现场设备通信,然后经过串口服务器,通过无线局域网实现现场设备与上位PC机的通信.实践证明:系统实现简单、通信可靠,并且具有很好的扩展性,基本满足了水源地远程监控的需求,提高了水...     

基于SIP协议的电力监控终端综合控管方法

本文针对在实际工作环境中对电力监控终端控管不当的问题,基于SIP协议设计了一种新的电力监控终端综合控管方法.该方法从会话协议、电力控管硬件、功能模块、通信协议以及任务实现几个角度展开研究,搭建高效率的终端控管平台.经实验验证可知,本文设计的会话协议平台能够高效地完成控管工作,从而提高电力监控工作的质量.     

基于GPRS的通用无线监控终端设计

本文介绍了基于GPRS模块的无线监控系统的工作原理,并设计实现了一种基于GPRS模块GR47和嵌入式微处理器PXA255的通用无线监控终端。     

基于双MCU结构的路灯远程监控终端设计

设计一种双MCU结构的路灯远程监控终端。该终端利用GPRS和电力载波通信技术,实现路灯监控的远程通信连接;并采用复合控制策略实现路灯精准控制。现场应用测试表明该监控终端性能稳定,实现了路灯监控的动态化远程管理。     

一种含铬电镀废水智能处理系统设计

p H调节、氧化还原电位(ORP)控制和比色测定是含铬废水还原-沉淀处理的典型方法。为实现远程监控和智能处理,配置处理终端RTU、Sink节点和上位机系统,利用Zig Bee网络建立了面向电镀废水处理的无线监测网。该系统通信可靠,能实现废水处理过程的远程监控,且大幅提高了精细化管理水平。     

基于GPRS的远程监控系统的研究与实现

设计了一种以单片机Atmega128A为控制核心,结合GPRS/GSM无线传输模块MC37I开发的无线数据终端,配合服务器及客户端软件构建了一种基于GPRS的远程监控方案。借助于无线数据终端和Internet,客户端能够对现场设备进行远程监视和控制。阐述了系统的总体方案,从硬件和软件两个方面具体介绍了无线数据终端的实现方法。     

基于B/S结构的空气源热泵热水机组的远程监控系统设计

设计基于B/S结构的空气源热泵热水机组的远程实时监控系统,介绍系统的体系结构、实现技术和软件功能.实际运行结果表明,该系统具有良好的稳定性、灵活性、扩展性和可维护性.     

Compact Swelling in Bi1.4Pb0.6Sr2Ca2Cu3.6Oy During the Formation of High-Tc Superconducting Phase

Compact swelling in Pb-doped Bi-Sr-Ca-Cu-O superconductor has been studied by observing the effects of the size of calcined powders, volatilization of materials, and sintering of high- T _c (2223) powders. The bulk density increases at the early stage of sintering, for about 20 h, and then decreases. Densification occurs when the low- T _c (2212) phase and a liquid phase exist, whereas dedensification occurs with the formation of the 2223 phase regardless of the presence of the liquid. Gas evolution from specimens does not appear to be responsible for compact swelling. Compact swelling is explained by anisotropic growth of thin, platelike 2223 grains in random orientation. When 2223 grains grow in a preferred direction, compact swelling is suppressed.     

Synthetic routes to nanoscale BxCyNz architectures

B_xC_yN_z nanoscale materials, hybrids of h-BN and graphite, have been recently synthesised using various techniques. Here, we present the latest advances in the synthesis and characterisation of B-C-N nanotubes and nanofibres. In particular, we focus on layered BC₂N, BN, BC and CN_x systems, reviewing their production methods as well as their structural and electronic properties. These materials may find important applications in the fabrication of nanotransistors, robust nanocomposites, conducting polymers, storage components and field emission sources.     

(Bi1/2Na1/2)TiO3–Ba(Cu1/2W1/2)O3 Lead-Free Piezoelectric Ceramics

(Bi_1/2Na_1/2)TiO₃ with 0–6 mol% Ba(Cu_1/2W_1/2)O₃ (BNT-BCW), a new member of the BNT-based group, has been prepared following the conventional mixed oxide route. The compacted bodies were sintered at 1130°C for 2 h to get dense ceramics. The addition of BCW into BNT ceramics facilitated the poling process because of a reduction in leakage current. 0.995BNT·0.005BCW ceramics exhibit a relatively high piezoelectric constant ( d ₃₃= 80 × 10⁻¹² C/N) and a relatively low dielectric loss (tan δ= 1.5%). Increased amount of BCW was found to increase the dielectric constant and loss of BNT-BCW ceramics and to suppress the grain growth. During sintering, some BCW diffuses into the lattice of BNT to form a solid solution and some remains on the grain boundaries.     

Structure Evolution from Pb(Mg1/3Nb2/3)O3 to La(Mg2/3Nb1/3)O3

The crystal structure of lanthanum-modified lead magnesium niobates having composition (Pb_{1− x} La _x ) (Mg_{(1+ x )/3}-Nb_{(2− x )/3})O₃ with X = 0 to 1 was investigated by X-ray powder diffraction. It was found that the fundamental reflections from perovskite structure remain in the whole range of composition. The superlattice reflections from the A(B'_1/2-B"_1/2)O₃ ordered structure are also well preserved for La content greater than 50 at.%; however, a series of extra peaks of mixing indices appears, with intensities gradually enhanced with the increase of La content. For the complete substitution of Pb by La, a splitting of some reflections can be observed in the diffraction pattern. The results indicate that the crystal structure evolves continuously with the La content, from disordered cubic perovskite of space group Pm 3 m for X = 0, to ordered cubic perovskite of space group Fm 3 m for X = 0.5, distorted cubic perovskite of space group Pa 3 for 0.5 < X < 0.9, and finally to a rhombohedral perovskite, possibly belonging to the space group R 3 , for X ≥ 0.9. In the evolution of structure, a linear reduction of the lattice constant of the perovskite cell from 4.048 to 3.964 Å was observed.     

炭黑/煤矸石/碳纳米管复合填料体系对天然橡胶性能的影响研究*

利用硝酸氧化法对碳纳米管(CNTs)进行纯化,并用环氧天然橡胶(ENR)进行改性处理。结合胶质量分数测定结果表明, ENR用量15%(质量)时效果最佳。采用胶乳凝聚法制备CNTs/天然橡胶(NR)母料。煤矸石粉(CG)经高温煅烧和表面改性处理。 将CNTs/天然橡胶(NR)母料、CG和炭黑(CB)通过机械混炼法与天然橡胶及配合剂混合,制备CB/CG/CNTs/NR复合材料,并对复合材料进行硫化特性及物理机械性能。结果表明： CNTs延迟硫化效应明显;相比炭黑,CG对硫化具有促进作用。硫化特性和甲苯溶胀法测定结果表明,在填料份数相同的条件下,单独由CB填充的NR有最大的交联密度,CNTs对交联密度影响不明显。物理机械性能测试结果表明,当CG：CB：CNTs=17.5:16.5:1(Phr)时,NR硫化胶的300%定伸应力和扯断伸长率明显高于单独由CB填充NR,而拉伸强度与之接近,复合填料样填充NR具有较好的综合性能。扫描电镜测试结果表明,复合填料在NR基体中分布均匀。     

Dielectric-State Analysis in Solid-Solution Pb(Yb1/2Ta1/2)O3–Pb(Lu1/2Nb1/2)O3

The structure and temperature dependence of complex lead perovskite dielectrics were investigated for the system (1 − x )Pb(Yb_1/2Ta_1/2)O₃– x Pb(Lu_1/2Nb_1/2)O₃. Superlattice reflections for the compositions 0.8 < x < 1.0 were observed by X-ray diffractometry, and the temperature-composition dielectric-state diagram was determined. In the present study, the disordered middle composition, with 0.2 < x < 0.8, showed a diffuse paraelectric–ferroelectric phase transition, whereas the ordered end compositions, with 0 ≤ x < 0.2 and 0.8 < x ≤ 1.0, revealed successive sharp paraelectric–antiferroelectric and weak antiferroelectric–ferroelectric phase transitions. The dielectric state was confirmed by examining the variation of polarization ( P ) with electric field ( E ).