TDCS技术在输油生产中的应用

介绍了一种集散控制集中监视输油生产的ＴＤＣＳ系统。该系统由工业控制计算机、可编程序逻辑控制器、现场仪表等组成,能对输油生产过程进行自动控制,并通过通信网将有关生产信息传输到有关部门。     

基于分布式无线网络的水质监控系统设计

为提高对水产养殖水质监控的实时性和测量精度,设计了一种基于无线传感器网络的水产养殖水质参数监控系统。该系统由水质参数采集终端、分布式传感器网络、传输控制中心基站、远程在线监控系统组成。参数采集终端采集水质参数并传输到中心基站,再通过GPRS发送给远程在线监控中心,根据用户向监控中心输入的参数实现水温、pH、溶氧(DO)的调节。参数测量过程中引入数字滤波算法提高测量精度,使用经过改进粒子群优化算法(PSO)整定的PID控制器实现水质参数的调节。结果显示:测量精度达到要求,温度、pH和DO的测量误差分别为2.1%、1.3%和3.6%,系统对温度、pH和溶氧调节的最大误差分别为1.9%、2.6%和3.1%。整个系统工作稳定可靠。     

一类二阶非线性中立型方程的振动定理

利用Φ(t,s,r)型函数和Riecati技巧,建立了一类具有连续分布滞量的二阶非线性中立型微分方程的一些新的振动准则.     

Modeling and simulation of the conducted electromagnetic interference for permanent magnet direct current motors

A simulation model for evaluation of conducted electromagnetic interference(EMI) is developed based on analysis of the mechanism giving rise to conducted EMI. The simulation model includes high frequency effects associated with stray distributed parameter     

Performance analysis and comparison of IEEE 802.11 distributed coordination function and improved schemes

To improve the media access control mechanism and enhance the performance of large scale wireless LANs, the distributed coordination function of IEEE802.11 standard and two typical improved schemes are studied extensively. Compared with the distributed coordination function, the fast collision resolution mechanism greatly enhances the throughput, but deteriorates the delay jitter and fairness of wireless LANs. The new self adaptive distributed coordination function markedly improves the delay jitter and fairness performance, while enhancing the throughput of wireless LANs to a certain degree. Hence, with further improvement, the new self adaptive distributed coordination function is more suitable for large scale wireless LANs for multimedia information transmission.     

Simulation of dissolved nitrogen pollution in Xiaojiang river basin of Three Gorges reservoir

Xiao Jiang River is the largest tributary on the north of the middle part in Three Gorges reservoir area, because of predominant hilly cropland with purple soil, the dissolved nitrogen from surface and subsurface runoff caused by raining accounts for most part of the nitrogen pollution in water. This paper develops the annual pollution models based on the characteristics of topography and soil, etc., of the basin in order to study dissolved nitrogen pollution, and introduces a Semi distributed Land Use based Runoff Processes (SLURP) hydrological model into the surface and subsurface runoff simulation which is an important part of non point source pollution modeling. Integrated with the geography information system technology, the annual temporal spatial distribution of the dissolved nitrogen in the basin is simulated and the load at the watershed outlet is estimated from 2000 to 2007. The results show that the load from cropland is up to 68.3~76.8of the total load, in which over 85 from croplands and then rural settlement is 23.2~31.7.     

环境安全型鸡场无线和短信监控系统的设计

介绍了将无线和短信结合起来对环境安全型鸡场进行监控的方法.系统采用集散控制方法,由无线智能传感器、无线监控通信终端、监控中心和执行节点等4部分组成.监控中心是整个系统的核心,对数据进行集中管理、分析和处理,其它部分负责数据的采集、传输和执行.     

黄土高原典型区雨水资源化潜力模拟与评价

为充分利用雨水资源应对黄土高原水土流失和干旱缺水的问题,引入分布式水文模拟技术,构建具有物理成因机制的分布式雨水资源化潜力评估模型,解决雨水资源利用的核心问题--评价当地的雨水资源化潜力。通过研究黄土高原典型区域黄河河口镇至龙门段(河龙区间)的雨水资源情况,定量评估该区域雨水资源化潜力,结果表明:在气候变化和人类活动的双重背景下,20世纪80年代后,黄河流域河龙区间的地表径流量、土壤有效水增量和雨水资源化潜力呈现上升趋势;河龙区间大部分地区雨水资源呈增长趋势,雨水资源可基本满足现有条件下区域植被恢复的用水需求。气候变化对雨水资源化潜力起正影响作用,贡献率为63.4%,土地利用/覆盖变化则为负影响,贡献率为-36.6%。人类活动对区域雨水资源利用的影响不容忽视,应大力发展干旱半干旱区降雨-径流调控技术,提高雨水资源化利用率,以保障区域生态-经济协同可持续发展。     

大渡河流域分布式水循环模型开发研究

大渡河流域是我国西南水电开发总体布局的重要靶区,也是南水北调西线工程的重要水源区.采用分布式水分能量传输模型(WEP模型),在地理信息技术的支撑下,构建了大渡河流域具有物理机制的分布式水循环模拟模型.模型水平单元为5 km×5 km的网格,采用马赛克法对单元的内的土地利用及植被分异进行处理;在垂直方向上,该模型可有效模拟冠层截流、填洼产流、入渗、植被蒸腾、水面和裸地蒸发垂直水循环要素过程.模型具有较好的模拟精度,在校正和验证期模型模拟误差(泸定站)均小于5%,Nash效率均在0.8以上.该模型可为区域水资源评价、生态影响评价等提供直接支撑,可为流域水电梯级开发调度和西线工程的运行调度提供支撑.     

浙江沿海大型底栖海藻分布区域与资源特征研究

根据对浙江沿海底栖海藻资源调查,研究分析了该区大型底栖海藻的种类数量,计56种,分隶5纲、13目,归入3个门,其中绿藻门15种,褐藻门20种,红藻门21种。该海区岩相潮间带底栖海藻资源丰富,其大型底栖海藻种类资源特征以我国沿海广温广布种（20种）和优势种类（16种）及常见种类（10种）占多数,其次为少见种类（5种）和稀有种类（4种）;平面分布种以暖温性种类（29种）占多数,其次为亚热带种类（22种）,而以冷水性种类（5种）为最少;其种类垂直生态分布特征以低潮带为最多,其次为中潮带,最少的是高潮带。最后提出了对浙江沿海大型底栖海藻资源开展生态保护和实施可持续开发的若干意见。