Enhanced frequency response estimator to guarantee pre-specified phase angle and static disturbance rejection with all harmonics removed

We propose a new frequency response estimation method in order to guarantee a pre-specified phase angle of the estimated model under static disturbance circumstances with rejecting harmonics completely. The proposed method uses one cycle of the conventional relay feedback signal followed by a sinusoidal signal. The sinusoidal signal in a cyclic steady state has no harmonics, resulting in exact frequency response estimates. Also, it guarantees the pre-specified phase angle and removes the effects of static disturbances by adjusting the reference value of the sinusoidal signal.     

Studies on the treatment of brilliant green solution by combination microwave induced oxidation with CoFe2O4

In this work the synergistic effects of microwave (MW) irradiation induced oxidation processes and CoFe₂O₄ were studied for the degradation of brilliant green (BG) from aqueous solutions. Under the optimum condition, the ratio of solid to liquid was 1:167 (0.3 g CoFe₂O₄ mixed with 50 mL of 20 mg L⁻¹ BG solution), MW power 600 W, and the time of the irradiation 2 min. And the decolorization rate could reach up to 100%. Further investigation showed that BG was degraded by MW-induced oxidation combined with CoFe₂O₄ surface adsorption. The CoFe₂O₄ could increase the efficiencies of MW degradation and be used repeatedly. The experimental results indicated that the method of MW degradation BG in the presence of CoFe₂O₄ could reduce reaction time and increase product yield.     

煤气、油双燃料系统在炉法炭黑中的应用

原料油短缺和高价位一直是制约炭黑行业健康发展的老问题,多年来炭黑界致力于研究或试用新的原材料来解决这个问题。目前有很多企业已经用天然气或焦炉煤气取代了炉法炭黑所使用的燃料油,并积累了丰富的应用经验,对缓解炭黑原料油供应紧张起到了一定的作用。天然气与焦炉煤气相比,具有热值高、供应稳定、操作使用简便等特点,非常适合作炉法炭黑生产燃料,     

Study of the performance of Mo2C for iso-octane steam reforming

In the present work, the performance of commercial molybdenum carbide (Mo₂C) for isooctane steam reforming has been investigated in order to determine the effects of major operating parameters (temperature, space velocity, and steam to carbon ratio) on the catalytic activity. While the results obtained indicate an onset reforming temperature of 850 °C, high concentrations of H₂ in the reforming environment were found to reduce the onset temperature to 750 °C. The catalytic activity at 850 °C was sufficient to produce hydrogen yields greater than 90% and carbon conversions close to 100%, with a low selectivity to CH₄ and CO₂. In addition, and consistent with thermodynamic predictions, a steam to carbon ratio of 1 appeared to optimize the reforming rates. Finally, based on experimental observations, a reaction mechanism was formulated and used to interpret the results obtained during catalytic activity measurements. This mechanism involves continuous oxidation and reduction of Mo metal, which can provide activity and stability to the catalyst when occurring at similar rates.     

钛酸钡添加量对埋容用环氧-钛酸钡-玻璃布板材性能的影响

采用热固化层压方法制备了环氧-钛酸钡-玻璃布(EBG)板材,并分析钛酸钡(BTO)添加量对埋容用EBG板材各项性能的影响。结果表明:随着BTO填料添加量的增大,EBG板材的实际密度先接近后偏离理论密度,孔隙率先减小后增大,耐浸焊时间、剥离强度先增大后减小,5%热分解温度和介电常数增大;当BTO的质量分数为80%左右时,埋容用EBG板材具有较好的综合性能;EBG板材为一种混联模型。     

用于空调器检测的带工况消声室优化设计

根据GB/T6882-2008,GB/T 7725相关要求,设计建造一套用于空调器噪声测试的带工况消声室。文章优化了消声室气流组织,采用对侧上送下回,变截面微孔送风的方式来满足室内工况,同时最大限度降低消声室背景噪声,有利于消声室内噪声测量的准确测定。     

基于PSpice软件的单相Boost变换器的仿真研究

随着计算机性能的提高,使用计算机仿真方法帮助掌握电气工程领域的基本知识并解决设计问题成为通用的方法。PSpice是一款功能强大的专用于电力电子电路的仿真软件,可对各种模拟电路及数字电路进行仿真,它的仿真波形与试验电路的测试结果十分相近。本文应用PSpice对Boost变换器的全部工作过程进行了仿真与分析,并对电路中储能元件的各种工作状态进行了分析,给出了大量直观的仿真波形,可以帮助加深对Boost变换器的理解。     

基于BACnet的智能小区监控系统的设计

针对智能小区内各机电设备通信协议不统一而使系统不能集成的问题,提出了采用BACnet协议进行集成的方法,BACnet是楼宇自动化和控制网络的开放标准,也是唯一的国际标准;本文通过对BACnet通信协议研究,用Vc＋＋软件设计了BACnet的对象类型、协议栈和应用层服务程序,并用BACnet测试实验室的测试软件VTS进行了测试;设计了智能小区监控系统的集成模型,将供配电子系统、给排水子系统和电梯子系统等集成在同一平台;系统功能测试结果表明,该系统运行可靠,可能很好的实现集中管理,减少用户后期的维护,为用户提供更多的方便。     

基于DDS的信号模拟器设计

通过对DDS的信号模拟器设计的研究,不仅设计出能够实现普通射频合成信号源的功能,正如能够在幅度、频率等方面对所需生成的信号加以控制,也能够实现定频、扫频以及跳频等输出方式上的选择。同时,该系统增加了叠加噪声和灵敏度设置,以便能够更好地实现对各种条件下雷达回波信号的模拟。     

博物馆照明现状分析及改进设计研究

博物馆承担文物保护和藏品展示两大功能,对室内环境有一定要求。其中光环境不仅对陈列展示的效果起重要作用,还可能引起光化学反应对文物造成伤害。本文通过对上海及其周边地区10余家博物馆进行实地调查和测量分析,发现当前博物馆照明方面普遍存在照度值超标、照度不均匀、观众对舒适度不满意等问题。文章针对这些问题进行了探讨,提出了可行的解决方法,并用照明软件DIALUX进行设计和仿真,有效地改善了这些问题,使得各项指标均达到现行国家标准,同时照度均匀、并且照明效果很好。