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基于nRF905和GPRS的智能家居用电监测系统
设计并实现了一种智能家居无线用电监测系统.该系统由具有无线射频信号收发功能的智能无线电参数测量插座、带有nRF905和GPRS模块的互动监测终端和家居远程监控中心组成.该用电监测系统既能测量电能参数以及电能消耗,同时又能根据现行家用电器运行状态给出科学合理的运行策略来控制家居中每个电器.系统可以在很大程度上提高家居中的电能利用率,并可以延长家用电器的使用寿命.董宇,杨强,颜文俊 - 电子技术应用文章来源: 万方数据 -
Now the optimization strategies for power distribution are researched widely,and most of them are aiming to the optimal fuel economy and the driving cycle must be preknown.Thus if the actual driving condition deviates from the scheduled driving cycle,the effect of optimal results will be declined greatly.Therefore,the instantaneous optimization strategy carried out on-line is studied in this paper.The power split path and the transmission efficiency are analyzed based on a special power-split scheme and the efficiency models of the power transmitting components are established.The synthetical efficiency optimization model is established for enhancing the transmission efficiency and the fuel economy.The identification of the synthetical efficiency as the optimization objective and the constrain group are discussed emphatically.The optimization is calculated by the adaptive simulated annealing(ASA)algorithm and realized on-line by the radial basis function(RBF)-based similar models.The optimization for power distribution of the hybrid vehicle in an actual driving condition is carried out and the road test results are presented.The test results indicate that the synthetical efficiency optimization method can enhance the transmission efficiency and the fuel economy of the power-split hybrid electric vehicle(HEV)observably.Compared to the rules-based strategy the optimization strategy is optimal and achieves the approximate global optimization solution for the power distribution.The synthetical efficiency optimization solved by ASA algorithm can give attentions to both optimization quality and calculation efficiency,thus it has good application foreground for the power distribution of power-split HEV.- 中国机械工程学报文章来源: 万方数据
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The existing research of the acceleration control mainly focuses on an optimization of the velocity trajectory with respect to a criterion formulation that weights acceleration time and fuel consumption. The minimum-fuel acceleration problem in conventional vehicle has been solved by Pontryagin's maximum principle and dynamic programming algorithm, respectively. The acceleration control with minimum energy consumption for battery electric vehicle(EV) has not been reported. In this paper, the permanent magnet synchronous motor(PMSM) is controlled by the field oriented control(FOC) method and the electric drive system for the EV(including the PMSM, the inverter and the battery) is modeled to favor over a detailed consumption map. The analytical algorithm is proposed to analyze the optimal acceleration control and the optimal torque versus speed curve in the acceleration process is obtained. Considering the acceleration time, a penalty function is introduced to realize a fast vehicle speed tracking. The optimal acceleration control is also addressed with dynamic programming(DP). This method can solve the optimal acceleration problem with precise time constraint, but it consumes a large amount of computation time. The EV used in simulation and experiment is a four-wheel hub motor drive electric vehicle. The simulation and experimental results show that the required battery energy has little difference between the acceleration control solved by analytical algorithm and that solved by DP, and is greatly reduced comparing with the constant pedal opening acceleration. The proposed analytical and DP algorithms can minimize the energy consumption in EV's acceleration process and the analytical algorithm is easy to be implemented in real-time control.- 中国机械工程学报文章来源: 万方数据
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Three dimensional(3D)displacements,which can be translated further into 3D strain,are key parameters for design,manufacturing and quality control.Using different optical setups,phase-shift methods,and algorithms,several different 3D electronic speckle pattern interferometry(ESPI)systems for displacement and strain measurements have been achieved and commercialized.This paper provides a review of the recent developments in ESPI systems for 3D displacement and strain measurement.After an overview of the fundamentals of ESPI theory,temporal phase-shift,and spatial phase-shift techniques,3D deformation measurements by the temporal phase-shift ESPI system,which is suited well for static measurement,and by the spatial phase-shift ESPI system,which is particularly useful for dynamic measurement,are discussed.For each method,the basic theory,a brief derivation and different optical layouts are presented.The state of art application,potential and limitation of the ESPI systems are shown and demonstrated.- 中国机械工程学报文章来源: 万方数据
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The accurate measurement on the compressibility and thermal expansion coefficients of density standard liquid at 2329kg/m3(DSL-2329) plays an important role in the quality control for silicon single crystal manufacturing. A new method is developed based on hydrostatic suspension principle in order to determine the two coefficients with high measurement accuracy. Two silicon single crystal samples with known density are immersed into a sealed vessel full of DSL-2329. The density of liquid is adjusted with varying liquid temperature and static pressure, so that the hydrostatic suspension of two silicon single crystal samples is achieved. The compression and thermal expansion coefficients are then calculated by using the data of temperature and static pressure at the suspension state. One silicon single crystal sample can be suspended at different state, as long as the liquid temperature and static pressure function linearly according to a certain mathematical relationship. A hydrostatic suspension experimental system is devised with the maximal temperature control error ±50 μK; Silicon single crystal samples can be suspended by adapting the pressure following the PID method. By using the method based on hydrostatic suspension principle, the two key coefficients can be measured at the same time, and measurement precision can be improved due to avoiding the influence of liquid surface tension. This method was further validated experimentally, where the mixture of 1, 2, 3-tribromopropane and 1,2-dibromoethane is used as DSL-2329. The compressibility and thermal expansion coefficients were measured, as 8.5′10–4 K–1 and 5.4′10–10 Pa–1, respectively.- 中国机械工程学报文章来源: 万方数据
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商务网站信息生态位测度方法研究
分析商务网站信息生态位的内涵,构造以能力维度、资源维度、关系维度、时间维度和空间维度为主的商务网站信息生态位5维模型,并设计出各生态位维度的指标体系,最后以此指标体系为基础设计出商务网站信息生态位的测度方法.张向先,霍明奎,孟楠 - 图书情报工作文章来源: 万方数据 -
无定型聚合物熔体的PVT特性
采用带有PVT口模的流变仪测定无定型聚合物熔体在压力0~50 MPa,温度453~563 K时的PVT(压力-体积-温度)特性曲线,分别用基团贡献修正胞腔模型(GCMCM)和胞腔模型对实测的PVT数据进行预测.结果表明:在实验中用基团贡献修正胞腔模型的比容平均预测误差较胞腔模型要大得多,其预测精度要略差于胞腔模型,这说明基团贡献修正胞腔模型的应用具有一定的局限性.同时还计算出了2种模型所对应的特征值,并分析了其特征值存在的共同点和差异的原因.王敏杰,陈灿波,刘莹 - 塑料文章来源: 万方数据 -
Differential Evolution with Adaptive Mutation and Parameter Control Using Levy Probability Distribution
贺仁杰,杨振宇 - 计算机科学技术学报(英文版)文章来源: 万方数据 -
声学多普勒水流剖面仪流量比测实验
声学多普勒水流剖面仪是目前较先进的河道测流设备.按《规范》要求,利用该仪器前,需要对该仪器与流速仪测流的实测流量进行对比实验,计算其换算系数.在分析ADCP测流原理的基础上,利用引黄干渠张二庄水文站实测流量资料,对两种测流方法测量结果进行对比分析.根据最小二乘法原理,建立回归直线,并对其进行检验.对回归直线进行拟合优度检验,拟合优度系数为0.982;对回归直线用F检验法进行截距检验,回归效果显著.在该断面用ADCP测流时,流量换算系数为0.9911.冯智学 - 南水北调与水利科技文章来源: 万方数据

