220V／250W恒功率高压钠灯电子镇流器的研究

根据高压钠灯的工作特性及电子镇流器的技术要求,研制成功基于L6574集成芯片的220V/250W恒功率高压钠灯高频电子镇流器。实验表明该电子镇流器工作稳定,无声谐振现象,输入电流谐波、灯电流波峰因数等均符合相关标准。本文分析了其高压点火电路,功率因数校正(PFC)电路,逆变及控制电路,此方案具有性能稳定、高功率因数、恒功率输出特性。     

基于SoC FPGA的CNC齿轮测量中心控制器设计

设计了一种基于Altera SoC的CNC齿轮测量中心控制器。该控制器通过以太网与计算机通信,内部的HPS与FPGA通过AXI总线通信。利用Qsys工具设计HPS与FPGA通信的命令解析组件,实现HPS与A/D控制模块、光栅计数模块、电机驱动模块通讯。设计HPS测试程序并进行测试,结果表明:基于SoC的控制器采样速度约为CAMAC控制器的10倍。     

基于电荷泵功率因数校正技术的小功率高压钠灯用电子镇流器

本文研究了输入电流连续型电荷泵功率因数校正(CIC-CPPFC)技术在电子镇流器中的应用,采用CIC-CPPEC技术实现的电子镇流器,与传统的双功率级电子镇流器相比,结构简单、电压应力低、功率密度高、成本低。本文成功设计出了一台适合50W高压钠灯用电子镇流器。实验表明,这种单功率级电子镇流器不仅能实现高压钠灯变频软启动,而且能保证在输入电网电压大范围变化时实现恒功率运行。它具有完善的多重保护功能,功率因数大于0.98,THD值小于15%。     

Luminogenic polymers with aggregation-induced emission characteristics

Aggregation-induced emission (AIE) is a newly developed phenomenon that is exactly opposite to the aggregation-caused emission quenching effect observed with some conventional luminophores. The AIE phenomenon was first realized in propeller-like small molecules and now has extended to polymeric systems. In this review, we summarize the recent progress on the preparation of luminogenic polymers with AIE or aggregation-enhanced emission (AEE) characteristics, which are generally prepared by attaching AIE-active luminogens, such as tetraphenylethene and silole, as pendants to the polymer backbones or utilizing them as skeletons for main chain polymers. An AIE phenomenon was observed in succinic anhydride-containing nonconjugated polymers bearing no luminogens, presumably due to the agglomeration of carbonyl groups. The AIE/AEE-active polymers show unique properties, such as emission superquenching, high and tunable light refractivity, and aggregation-enhanced two-photon excited fluorescence, and have found potential applications as fluorescent sensors, biological probes, and active layers for the fabrication of light-emitting diodes.     

新型耐候桥梁钢A709M—HPS485W的开发

通过舞钢新型跨海大桥用钢HPS485W的研发生产,介绍了HPS钢的概况,对生产关键工艺、焊接试验等进行了详细阐述,对舞铜供旧金山新海湾大桥项目用HPS485W的实物性能进行了简要介绍。     

Dynamic modeling of a hybrid wind/solar/hydro microgrid in EMTP/ATP

Microgrids are LV or MV electric networks which utilize various distributed generators (DG) to serve local loads. In this paper, dynamic models of the main distributed generators including photovoltaic (PV) cell, wind turbine, hydro turbine as well as the equivalent power electronic interfaces, battery unit of PV and excitation system of hydro turbine have been made in ElectroMagnetic Transient Program/Alternative Transient Program (EMTP/ATP) software package. Control strategies based on active power/frequency and reactive power/voltage droops for the power control of the inverters have been also developed. Case studies have been carried out in a distribution network to investigate the dynamic behavior of the micro-sources in both steady state and fault scenarios. Simulation results verify the feasibility of the proposed models.     

Starting of HPS lamps driven by electronic ballast

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具有软启动功能的高压钠灯电子镇流器研究

高压钠灯配接传统电感镇流器启动时灯电流对阴极冲击过大,缩短了高压钠灯的实际使用寿命。而且路灯群点亮时只能采用分批分段的控制方式,造成管理上的困难。为此提出了一种高性能电子镇流器的设计方案。通过控制电子镇流器功率逆变级的工作频率来降低高压钠灯启动时的电流,从而实现软启动。试验结果表明,所设计的电子镇流器具有近似为1的功率因数,并能有效地降低启动电流对灯的冲击,从而延长灯的使用寿命,克服了传统电感镇流器的弊病。     

高性能钢桥在北美的研究及应用简介

美国进行了大量的研究工作来研发强度、可焊性、韧性、耐候性和制造性更优良的高性能钢(HPS),并已成功研制了HPS50W、HPS70W和HPS100W三种高性能钢。同时,美国在40多个州的桥梁中采用HPS,这些桥梁体现了良好的结构性能和经济性。在此基础上,为了使HPS更加有效的应用于桥梁,美国对公路桥梁设计规范(AASHTO)做了很大的改进,允许工程师采用HPS。加拿大着重于HPS疲劳性能的研究,Alberta大学率先开展了这方面的研究工作,目前正深入研究HPS焊接细节的疲劳性能。为了获得HPS的使用经验,加拿大计划建造一座采用HPS485W的试验桥梁。     

Evaluation and Enhanced Use of Light Emitting Diodes for Hydroponics

Hydroponic farming is a viable and economical farming method,which can produce safe and healthy greens and vegetables conveniently and at a relatively low cost....