Synthesis and microwave characterization of Co-SiC core-shell powders by electroless plating

Co-SiC core-shell powders were prepared by electroless plating. Scanning electron microscopy （SEM） revealed that Co-SiC core-shell powders were of nearly sphere-like shape and were about 0.3 pan. X-ray powder diffraction （XRD） patterns showed that the cobalt powder was hexagonal crystallite. The complex dielectric constant and the complex permeability of Co-SiC core-shell powders-paraffin wax composite were measured by the rectangle wavegnide method. It showed that the dielectric loss was less than 0.1 and the magnetic loss was about 0.2 in 8.2-12.4 GHz for prepared Co-SiC core-shell comoosite oowders.     

基于IFCM的共址接地极带电作业安全问题研究

针对共址接地极线路特殊运行工况及过电压分布特点,提出一种基于改进模糊C均值聚类（IFCM）的带电作业安全评估方法。首先通过建模并仿真计算获取共址接地极线路特殊运行工况下的过电压分布,确定了最大操作过电压;然后通过建立共址接地极放电试验模型开展冲击放电试验,利用改进的模糊 C 均值聚类对典型间隙的试验结果进行聚类,以达到获取各间隙放电电压U50的目的;最后通过绝缘配合方法确定共址接地极带电作业安全间隙距离,并结合实际工程进行安全性分析验证。所提出的研究方法和结论可为共址接地极线路带电作业的安全开展提供参考。     

GIL机械故障诊断与预警技术研究

为了有效诊断气体绝缘金属封闭输电线路(GIL)的机械故障,搭建了110 kV GIL试验平台并设计了3种典型机械故障,通过互补集合经验模态分解(CEEMD)模糊熵值与鲸鱼优化极限学习机(WOA-ELM)模型联合方法对GIL机械故障模式进行识别与诊断。首先,利用CEEMD方法对振动信号进行分解,引入正负白噪声组对信号进行处理,得到含有故障信息的模态分量(IMF)。其次,利用模糊熵计算模态分量特征值,得到能表征故障特征的模糊熵值。最后,结合WOA-ELM模型对特征向量集进行模式识别,根据聚类结果与自适应阈值对GIL设备机械故障进行诊断和预警。结果表明,利用CEEMD与模糊熵对GIL振动信号特征进行分析,可以有效避免模态混叠和冗余噪声分量的干扰,得到能够表征故障特征的特征值;利用WOA-ELM模型可以有效实现GIL设备机械故障诊断与预警。     

站用电切换中调相机循泵电机的瞬态分析

特高压（UHV）变电站在站用电切换过程中,调相机循泵电机会出现冲击电流过大导致多级跳闸的情况。为研究切换策略,首先定量分析失电残压的频率和幅值随时间的变化,并进行相关仿真研究。其次对重合闸时的瞬态进行研究,通过仿真模型得到冲击电流随时间的变化规律,发现冲击电流的最大值略滞后于相位相反的点,最小值略滞后于相位相同的点,且该滞后的量取决于失电残压的衰减速率,提出一种基于失电残压和电源电压幅值差的切换方法。针对仿真结果进行分析,为维护人员提供一定的参考依据,尽可能降低投切过程中的冲击电流,避免切换失败。     

Enhanced luminescent performance of 1,8-naphthalic anhydride-loaded bimodal mesoporous silicas modified by europium nitrate

Journal of Porous Materials - Eu(NO3)3 was selected as an enhancer to improve the performance of luminescent hybrid bimodal mesoporous silica (LHMS), and a series of LHMS-EN(x)...     

基于需求响应的用户侧综合能源系统分布式博弈均衡策略

用户侧综合能源系统是未来能源消费方式的重要发展方向,实现用户侧综合能源系统的运行优化可以提高其经济效益和环境效益.为此,建立了由多个分布式能源站和多个能源用户组成的用户侧综合能源系统能源交易模型,提出了基于需求响应的用户侧综合能源系统分布式博弈均衡策略.分布式能源站最大化各自收益,能源用户则以各自效用最大化为目标,首先,通过对偶分解将初始问题分解为多个子系统的需求响应优化问题,然后,对各个子系统的需求响应优化问题进行分布式求解.该方法的主要优点是,能源交易实现分布式博弈均衡,各方不需要中央控制器或者任何第三方,同时各市场成员信息隐私得到了保障.最后,通过算例验证了所提用户侧综合能源系统分布式博弈均衡策略的有效性.     

A multi-objective study on the constructal design of non-uniform heat generating disc cooled by radial- and dendritic-pattern cooling channels

A three-dimensional disc model with non-uniform heat generating is built. A series of cooling channels are inserted to cool this disc which is strewn in a hierarchical pattern. To reveal thermal and flow characteristics, a composite objective function comprised of the maximum temperature difference(MTD) and pumping power is constructed. The deployment pattern of cooling channels contains two cases, i.e., the radial-pattern and dendritic-pattern. By capitalizing on constructal design method together with finite element method, the diameter of radial-pattern cooling channels is optimized in the first place. Next, the diameter, angle coefficient and length coefficient of dendritic-pattern cooling channels are three degrees-of-freedom to be stepwise optimized at different heat generating conditions. Furthermore, NSGA-II algorithm is introduced into the multiobjective problem. Upon obtaining its Pareto optimal solution set, Topsis method is invoked to yield the optimal solutions under given weighted coefficients. The heat generation over the entire body and the volume ratio of cooling channels operate as the primary constraints. Based on these premises, constructal design will be stepwise performed by varying three degrees-offreedom. The obtained results state that more heating components or devices should be installed as close to the cooling water inlet as possible. This can further reduce MTD at the same cost of pumping power, thereby improve thermal and flow performance and prolong the lifespan of devices. As optimized with two degrees-of-freedom, the MTD is reduced by 18.6%compared with the counterpart obtained from single degree-of-freedom optimization, while the pumping power is increased by 59.8%. As optimized with three degrees-of-freedom, the MTD is decreased by 6.2% compared with the counterpart from two degrees-of-freedom optimization, while the pumping power is increased by 3.0%. It is manifest that when two sub-objectives form a composite objective, the performance improvement of one sub-objective will inevitably elicit the vitiation of the alternative.     

航空电励磁双凸极无刷直流起动发电机系统控制关键技术综述

电励磁双凸极电机具有结构简单可靠、容错性能好、控制灵活等优势,可构成一种具有竞争力的新型航空无刷直流起动发电机系统。简述了电励磁双凸极起动发电机系统的构成及其工作原理。针对航空电源这一特殊应用领域的要求,对电励磁双凸极起动发电机高可靠性控制、高效率高功率密度控制、集成化控制等关键技术进行了归纳总结。讨论了电励磁双凸极起动发电机控制关键技术的未来发展趋势。     

考虑储能的工业园区综合能源系统日前优化调度

城市能源互联网系统通过互补和能量梯级利用,实现能源资源的有效整合,在能源生产和消费革命中起着重要作用。城市能源互联网建设的关键之一是建立城市工业园区综合能源系统。因此,围绕一个存在电、热、冷、天然气等多种能流并服务于生产生活负荷统筹的工业园区综合能源系统开展了建模,结合系统储能特性,提出了日前运行优化调度模型。该模型综合考虑了供能管网和储能水罐储能特性及其对经济效益的影响,针对涉及生产生活用能的工业园区进行优化,同时对供能管网储能能力进行量化。这一技术被应用于某实际工业园区,进行冬季供暖工况运行调度优化。储热水罐的出力优化增加了系统设备组合的灵活性,而热网热惯性的考虑稳定了机组出力。优化方案表现出更好的经济性和输出稳定性,单日节省运行成本1 445元。     

基于双向耦合的综合能源系统电热联合潮流计算

本文针对综合能源系统电热联合潮流计算问题,首先基于电热双向耦合建立了含有2个热电联产机组（CHP）耦合节点的电热双向耦合潮流模型;然后分析了电锅炉的耦合状态和系统负荷变化对系统潮流的影响;最后基于牛顿拉夫逊顺序求解算法,选取某一区域综合能源系统进行算例分析,利用MATLAB软件求解出电热混合潮流。结果表明:电热双向耦合网络通过耦合节点CHP1、CHP2交互作用,相互影响达到潮流平衡,验证了所给模 型的有效性;电热耦合潮流随着电锅炉耦合状态和系统负荷变化而变化,显示出多能流系统源-网-荷互动特性。通过对电热耦合网络的潮流研究,可以为电热耦合综合能源系统的规划运行提供指导,并且为进一步多能流耦合潮流研究提供思路。