液黏软起动装置控制油压调节特性的分析

通过对软启动装置控制油路原理的分析,得出液压泵输出的流量一部分通过节流阀流回油箱,另一部分进入液黏软起动装置后通过内部泄漏流回油箱。进一步推导出通过变频器调节定量泵转速调节液压系统时系统油压与电源频率的关系并建立了动力学模型。并使用MATLAB软件对系统控制油压的可控性进行了分析。     

鞍钢高炉冲渣水溢流问题的分析与控制

鞍钢股份有限公司炼铁总厂高炉冲渣工艺多样、复杂,针对不同的高炉冲渣工艺特点,分析了影响高炉冲渣水溢流的问题,提出了改进措施,实现了高炉冲渣水内部动态平衡,逐步实现高炉冲渣水的零排放。     

退火温度对CuGa_(0.8)Ge_(0.2)Se_2薄膜结构及光学特性的影响

采用脉冲激光沉积法在SiO2衬底上制备了CuGa0.8Ge0.2Se2薄膜。采用X射线衍射和X射线能谱仪研究了退火温度对薄膜晶体结构和成分的影响,利用扫描电子显微镜表征了薄膜的表面形貌,采用紫外—可见分光光度计分析了薄膜的光学特性。结果表明,在CuGaSe2中掺杂Ⅳ族元素Ge,光子吸收能量分别为0.65和0.92 e V,禁带宽度为1.57 e V,能够形成中间带。并随着退火温度的升高,CuGa0.8Ge0.2Se2薄膜的光学带隙逐渐减小。     

近零能耗建筑中相变建筑材料的研究进展

近零能耗建筑是采用被动式建筑设计和主动式节能技术、以最低的能源设备功耗获得舒适室内环境的建筑。相变建筑材料的使用可以提高建筑围护结构的热惰性,减少室内温度的波动,降低供暖、空调设备的容量,同时能与太阳能、空气能等可再生能源相结合,降低建筑设备能耗。从不同围护结构的角度介绍了相变建筑材料的分类与特点,综述了国内外相变围护结构的研究进展,列举了相变建筑材料在近零能耗建筑中的被动式设计案例。分析了相变建筑材料的研究方向,以及相变建筑材料在被动式设计和主动式节能技术上的发展趋势,为近零能耗建筑的研究和设计提供参考和依据。     

零能耗建筑实现的能耗分配控制策略设计研究

本文针对国家机关办公建筑和大型公共建筑日益突出的高能耗问题,以中新天津生态城公屋展示中心"零能耗建筑"实现的能耗分配控制策略设计为例,研究从"零能耗建筑"能耗的相关问题出发,以能耗采集和数据分析方法、能耗分配和节能控制策略作为研究对象,设计预期达到设计能耗和运行能耗相吻合的结果,实现真正意义上的"零能耗建筑"。     

一类四元零相关区非周期互补序列集构造法

零相关区非周期互补序列集在多载波码分多址通信系统中有着重要应用.已有的四元零相关区非周期互补序列集构造方法都是基于二元或四元零相关区互补序列集,得到的序列集参数受到初始互补序列集参数的限制.该文给出了一种构造法,利用四元正交序列集来构造四元非周期互补序列集.本文方法得到的序列集参数达到理论界限,并且零相关区长度可以灵活设定以满足不同的应用场合.另外给出了两类基于二元正交矩阵的四元正交序列集的构造方法,得到的四元正交序列集可以用于构造四元零相关区非周期互补序列集.二元正交矩阵存在数目很多,因此本文方法可以为多载波码分多址系统提供大量四元非周期互补序列集.     

An efficient algorithm for low-order direct discrete-time implementation of fractional order transfer functions

Fractional order systems become increasingly popular due to their versatility in modelling and control applications across various disciplines. However, the bottleneck in deploying these tools in practice is related to their implementation on real-life systems. Numerical approximations are employed but their complexity no longer match the attractive simplicity of the original fractional order systems. This paper proposes a low-order, computationally stable and efficient method for direct approximation of general order (fractional order) systems in the form of discrete-time rational transfer functions, e.g. processes, controllers. A fair comparison to other direct discretization methods is presented, demonstrating its added value with respect to the state of art.     

Analytical fractional PID controller design based on Bode’s ideal transfer function plus time delay

In this paper, a fractional order PID controller cascaded with a fractional filter is proposed for higher order processes. In this analytical design methodology, one or two reduced fractional orders plus time delay models are used to represent higher order system transfer functions. The controller parameters are determined so as to meet certain frequency domain specifications. A unity feedback reference model is employed where Bode’s ideal loop transfer function plus time delay of the fractional order model is placed in the forward path. The addition of this time delay provides the exact determination of frequency domain specifications if the system either intrinsically owns a time delay or a time delay is injected by its reduced order model. The proposed methodology is compared with two other related methodologies and it has been observed that the proposed controller performs much better than the others. Moreover, some empirical formulas for time domain characteristics of the reference model are numerically derived in terms of certain frequency domain specifications and time delay of the fractional reduced order model. The accuracy of these formulas is tested by simulations. The iso-damping, noise attenuation and load disturbance suppression performances of the proposed controller are also considered and compared with those of other related controllers.     

中高温烟气干燥脱硫废水过程研究

脱硫废水零排放(ZLD)已成为现阶段环境治理的趋势,传统的治理方法具有高成本、难维护等缺点,因此提出一种利用中高温烟气干燥电厂脱硫废水的新技术。通过将选择性催化还原(SCR)脱硝后的热烟气引入喷雾干燥器,雾化废水使其与烟气充分接触,经干燥进入空气预热器后的原烟道。结果表明:抽取锅炉烟气量的7%左右可干燥脱硫废水2.5 t,使锅炉热效率降低0.68%左右,影响较小。干燥后烟气酸露点温度从93.20℃提高到96.72℃,不会腐蚀空气预热器等后续工艺设备,同时该技术有利于静电除尘器(ESP)、湿法烟气脱硫(WFGD)系统的运行,利用中高温烟气干燥脱硫废水是可行且有效的技术方法。     

钼冶炼厂生活污水和工业废水零排放实践

介绍了某钼冶炼厂废水处理系统的改造实践情况。通过采用AO脱氮技术的地埋式一体化装置代替原有的两级生化曝气池等改造,处理后的生活污水出水COD在50 mg/L以下,氨氮质量浓度在15 mg/L以下,可全部回用于厂区作为绿化及道路清扫等用水;通过增加两级曝气池、pH调节池和溢流水槽对工业废水进行处理后,生产废水出水清澈透明,无杂色,满足GB 8978—1996《污水综合排放标准》一级标准要求,可达标排放或回用,实现了废水的循环利用和零排放,节约了水资源。