基于EPON技术的配、用电网通信系统建设的研究

从配用电网通信系统的现状、技术体系以及配用电网通信系统建设的关键技术和存在的问题等方面,阐述了配用电网通信系统建设的技术可行性,为未来配用电网通信系统的建设提供借鉴,满足智能化电网的发展要求。     

斜线PWM及其派生电流跟踪方法

对用于电压型脉宽调制（pulsewidthmodulation,PWM）变换器的滞环法进行分析。首先提出抛物线PWM电流跟踪方法,该方法将抛物线状的电流环与纹波电流（误差电流）比较产生开关频率基本恒定的PWM信号,并进而提出开关频率更稳定的改进抛物线法,最后提出斜线法,该方法将纹波电流斜率与斜线状的电流环比较,产生开关频率基本恒定的PWM信号,且能在一个开关周期内使变换器电流精确跟踪电流指令值。以半桥电压型PWM变换器为例,仿真验证了上述方法的有效性。     

基于光纤光栅应变传感器的架空输电线弧垂实时监测

利用光纤的应变与Bragg波长的对应关系,分别得出了架空输电线悬点等高以及不等高条件下的输电线弧垂计算方法;提出了一种基于光纤布拉格光栅（fiber Bragg grating,FBG）应变传感器的架空输电线弧垂实时监测方案,通过监测线路的应变值,可以获得线路的实时弧垂值。仿真计算结果表明,本方案可实时监测10 m以上的弧垂变化,且能够支持16 mm的弧垂测量精度,具有较高的工程应用价值。     

基于人工鱼群算法的PSS参数优化

基于电力系统分析综合程序PSASP的小干扰线性化平台,提取系统的增广矩阵;根据电力系统稳定器(PSS)的线性化微分方程,找到PSS对应增广矩阵的子阵位置.在优化过程中得到PSS参数后更新增广矩阵中的相关元素,生成新的增广矩阵,为PSS参数优化提供数据处理对象.使用带有变异因子的人工鱼群优化算法对PSS进行参数优化,通过各人工鱼个体的局部寻优最终找到群体中全局最优值.优化的目标函数为多种运行方式下所有机电振荡模态中的最小阻尼比最大化.新英格兰系统的算例表明使用人工鱼群算法配置的PSS能够有效增强系统的小干扰稳定性.     

Preparation and electrochemical properties of La<Subscript>1.0</Subscript>Sr<Subscript>1.0</Subscript>FeO<Subscript>4+δ</Subscript> as cathode material for intermediate temperature solid oxide fuel cells

Cathodic material La_1.0Sr_1.0FeO_4+δ for an intermediate temperature solid oxide fuel cell (IT-SOFC) was prepared via the glycine-nitrate process and characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). XRD results showed that no reaction occurred between the La_1.0Sr_1.0FeO_4+δ electrode and Sm_0.2Ce_0.8O_1.9 (SDC) electrolyte at 1000 °C. SEM results showed that the electrode formed good contact with the SDC electrolyte after sintering at 1000 °C for 2 h. The electrochemical properties of La_1.0Sr_1.0FeO_4+δ were measured using electrochemical impedance spectroscopy (EIS) and steady state polarization measurement. At 700 °C, the polarization resistance was about 3.90 Ωcm², and the lowest polarization overpotential was 57 mV at a current density of 55 mA cm⁻².     

自适应预测法在去噪声中的应用

在信号检测中,突变点和脉冲点的检测尤为重要,本文首先用多项式预测法找出输入信号的突变点和脉冲点。并证明了预测因子之和为１．文中将时装城的一维信号看成有产品,,上突变点信号按谱系分成多类,然后对每一类用多项式预测法,即左预测和右预测去除脉冲噪声和白噪声,该方法能有效的保护信号的突变现象。     

Achieving Rich and Active Alkaline Hydrogen Evolution Heterostructures via Interface Engineering on 2D 1T‐MoS2 Quantum Sheets

Large‐scale production of hydrogen from water‐alkali electrolyzers is impeded by the sluggish kinetics of hydrogen evolution reaction (HER) electrocatalysts. The hybridization of an acid‐active HER catalyst with a cocatalyst at the nanoscale helps boost HER kinetics in alkaline media. Here, it is demonstrated that 1T–MoS₂ nanosheet edges (instead of basal planes) decorated by metal hydroxides form highly active ${\text{edge}}_{{\text{1T‐MoS}}_{\text{2}}}$/ ${\text{edge}}_{\text{Ni}{(\text{OH})}_{\text{2}}}$ heterostructures, which significantly enhance HER performance in alkaline media. Featured with rich ${\text{edge}}_{{\text{1T‐MoS}}_{\text{2}}}$/ ${\text{edge}}_{\text{Ni}{(\text{OH})}_{\text{2}}}$ sites, the fabricated 1T–MoS₂ QS/Ni(OH)₂ hybrid (quantum sized 1T–MoS₂ sheets decorated with Ni(OH)₂ via interface engineering) only requires overpotentials of 57 and 112 mV to drive HER current densities of 10 and 100 mA cm^?2, respectively, and has a low Tafel slope of 30 mV dec^?1 in 1 m KOH. So far, this is the best performance for MoS₂‐based electrocatalysts and the 1T–MoS₂ QS/Ni(OH)₂ hybrid is among the best‐performing non‐Pt alkaline HER electrocatalysts known. The HER process is durable for 100 h at current densities up to 500 mA cm^?2. This work not only provides an active, cost‐effective, and robust alkaline HER electrocatalyst, but also demonstrates a design strategy for preparing high‐performance catalysts based on edge‐rich 2D quantum sheets for other catalytic reactions.     

基于电容的手势识别系统

传统手势识别装置一般依赖于复杂计算设备,在简单场合配置手势识别装置成本过高。针对这一问题,提出了基于电容数字转换器的手势识别系统。具体实施过程中,电容数字转换器采集静态手势特征,滑动窗口滤波加工特征数值,再结合K邻近分类算法判别静态手势。该系统具有对硬件要求低、功耗小、对环境光强不敏感等优点。经过50次试验,系统对于常用的数字零到五手势识别正确率为98%,判别时间小于0.6 s。     

同步光分组交换网核心节点光分组长度分析

研究了同步光分组交换网中光分组长度的设计及其对一些网络性能参数的影响,分别推导了光分组中开销所占比率、时延及光纤延时线长度与光分组长度的关系,并给出各自相应的理论分析和数值解析,为光分组中分组长度的设计做了基础工作。     

回波功率筛选与数字地表分类数据辅助的低空风切变风速估计方法

针对非均匀杂波环境下,低空风切变风速估计不准的问题,该文提出一种回波功率筛选与数字地表分类数据(DLCD)辅助的低空风切变风速估计方法.该方法首先利用样本回波功率对训练样本进行初选,然后利用DLCD计算各样本间的相似度,并从功率较大的训练样本中选取样本相似度较高的训练样本估计待测距离单元的杂波协方差矩阵,最后利用广义相邻多波束(GMB)-局域联合处理(JDL)的方法实现低空风切变风速的有效估计.