A Novel Diversity-Controlled Genetic Algorithm for Rapid Optimization of Bandpass FRM FIR Digital Filters Over CSD Multiplier Coefficient Space

The conventional frequency response masking (FRM) approach is one of the most well-known techniques for the design of sharp transition band finite impulse response (FIR) digital filters. The resulting FRM digital filters permit efficient hardware implementations due to an inherently large number of zero-valued multiplier coefficients. The hardware complexity of these digital filters can further be reduced by representing the remaining (non-zero) multiplier coefficient values by using their canonical signed-digit (CSD) representations. This paper presents a novel diversity-controlled (DC) genetic algorithm (GA) for the discrete optimization of bandpass FRM FIR digital filters over the CSD multiplier coefficient space. The resulting bandpass FIR digital filters are permitted to have equal or unequal lower and upper transition bandwidths. The proposed DCGA is based on an indexed look-up table of permissible CSD multiplier coefficients such that their indices form a closed set under the genetic operations of crossover and mutation. The salient advantage of DCGA over the conventional GA lies in the external control over population diversity and parent selection, giving rise to a rapid convergence to an optimal solution. The external control is achieved through the judicious choice of a pair of DCGA optimization parameters. An empirical investigation is undertaken for choosing appropriate values for these control parameters. The convergence speed advantages of the DCGA are demonstrated through its application to the design and optimization of a pair of bandpass FRM FIR digital filters with equal or arbitrary lower and upper transition bandwidths. In both cases, an increase of about an order of magnitude in the speed of convergence is achieved as compared to the conventional GAs.     

莱钢2~#高炉改善渣铁流动性操作实践

针对莱钢2#高炉烧结矿中TiO2的含量增加,导致渣铁粘稠的情况进行分析,采取了低硅冶炼等一系列措施改善铁水流动性,保证高炉稳定顺行。     

高炉炉缸区钒氧化物的还原试验

炉缸区钒氧化物的还原对钒的收得率具有重要影响。通过研究炉渣成分和温度对钒氧化物还原的影响,结果表明:二元碱度对钒氧化物还原影响显著,钒氧化物的还原率随着二元碱度的增加而增加;MgO、Al_2O_3含量增加,钒氧化物的还原率先升高后降低;TiO_2含量增加,钒氧化物的还原率降低,且TiO_2含量超过11%时钒氧化物的还原率大幅降低;钒氧化物的还原率随着温度的增加而升高。当承钢高炉渣的二元碱度1.2、Al_2O_3含量14%、MgO含量10%、TiO_2含量9%、炉渣温度控制1 500℃时,钒氧化物的还原达到最佳,还原率达到90%左右。     

Equilibrium piezoelectric potential distribution in a deformed ZnO nanowire

The equilibrium piezoelectric potential distribution in a deformed ZnO semiconductive nanowire has been systematically investigated in order to reveal its dependence on the donor concentration, applied force, and geometric parameters. In particular, the donor concentration markedly affects the magnitude and distribution of the electric potential. At a donor concentration of N _D>10¹⁸ cm⁻³, the piezopotential is almost entirely screened. Among the other parameters, a variation in the length of the nanowire does not significantly affect the potential distribution.      

型式试验对挤塑绝缘高压直流电缆老化状态的影响研究

通过对国内自行研制的200 k V挤塑绝缘交联聚乙烯电缆的空间电荷、松弛电流和热性能进行测试,分析了型式试验对电缆绝缘的影响。型式试验前后,主绝缘中部切片试样在表面区域均存在明显的异极性空间电荷分布,且电荷积累量变化不大,状态因子、熔融热焓、结晶热焓和交联度变化亦不明显,表明型式试验对电缆中部绝缘的老化程度影响较小。切片脱气处理后,试样表面区域的异极性空间电荷积累和短路时空间电荷平均单位体积密度显著降低,表明空间电荷行为受制造过程中残留的交联副产物影响很大。空间电荷、等温松弛电流和差示扫描量热的测试结果的关联性较好,均能有效反映老化状态的变化,可用于挤塑绝缘直流电缆的绝缘状态评估。     

谐波电流相位对滤波电容器噪声的影响

电力电容器在交流谐波电压作用下会产生显著的噪声。目前国内外已经研究总结了电容器噪声频率与谐波电压间的关系以及谐波电压幅值对噪声的影响,但并没有对谐波电压的相位对噪声的作用进行研究。本文从电容器振动噪声激励出发,分析了谐波电压相位对电容器极板间电场力关系,进而得到相位对噪声的影响规律。并通过电容器单元的噪声试验,验证了电容器单元加载相位对噪声的影响。试验结果与理论分析相一致,并且发现,对于全奇次谐波的作用,当谐波初相位为0°时,电容器单元声功率最大;当频率相差100Hz谐波的初相位相差180°时,电容器单元声功率最小。     

带电水冲洗水柱打击力特性

带电水冲洗采用高电阻率水清洗绝缘子表面污秽,水柱打击力过大不利于绝缘子安全,水柱打击力过小又不利于污秽的彻底清除。建立了带电水冲洗水柱冲洗打击力实验系统,测试了中、大水冲洗三种典型喷嘴在不同冲洗角度、不同出口压强以及不同水柱长度下的水柱打击力,得到了水柱打击力与出口压强、水柱长度间的定量关系及三种喷嘴在典型带电水冲洗工况下打击力的变化范围,对进一步认识带电水冲洗水柱压力特性、带电水冲洗污秽清洗机理以及安全高效地开展带电水冲洗作业控制具有重要的理论和实践意义。     

工业数据空间（IDS）技术概述及其测试床部署实践

全球主要国家积极开展工业数据空间研究的背景下,本文首先介绍了工业数据空间的概念内涵和4个典型应用场景,其次基于应用和需求,介绍了工业数据空间的整体架构,然后从业务、数据与服务、软件及安全等技术层面阐述了工业数据空间的参考架构模型,最后基于东方电气集团内部数据模型传输的场景,搭建了测试床,验证了系统部署的可行性。     

光学电压传感器分压结构的缺陷及改进方法

现有的光学电压传感器多基于光功率检测模式,其测量范围与测量灵敏度受到电光晶体半波电压的限制。纵向调制的多片晶体叠层结构可以解决半波电压限制的问题,但仅适用于1 000 kV电压等级。此外,仿真结果表明这一结构中晶体内的电场分布极不均匀,受震动与热胀冷缩等因素的影响,光路或晶体的相互位置易产生偏移而引入积分电压误差。文中以110 kV电压等级为例,对多片晶体叠层结构进行了改进,简化了传感系统的结构,并将MgTiO₃陶瓷按照一定的要求安装在锗酸铋(BGO)晶体的外部以改善晶体的内电场分布,可以把积分电压误差从0.275%降低至0.01%以下。改进后的结构可用于各种电压等级。最后,通过实验验证了新方法的有效性。     

基于图形处理器加速的电网全网拓扑分析算法

随着电网规模的扩大以及电力系统互联水平的提高,电网分析计算的计算量显著上升.图形处理器(GPU)等并行计算设备能够提高大电网分析的计算效率,但电网分析计算中的串行电网拓扑分析已经成为影响并行算法计算效率的重要因素,亟待得到加速.作为电网拓扑分析加速问题的难点,全网拓扑分析可采用并行算法进行加速.为此,提出了一种基于GP...