化工过程pH值的模糊免疫PID控制

针对化工过程pH值变化的非线性、时滞特点,提出一种模糊免疫PID控制方法;该方法依据生物免疫原理设计免疫反馈PID控制器,并使用模糊控制器来实现免疫反馈的非线性函数,然后优化控制器的参数,最后借助MATLAB工具进行仿真实验;PID控制器比例控制由公式5计算,其参数优化结果为K=4.5,η=2.0,Ki=0.009,Kd=6.0。仿真结果显示,模糊免疫PID控制效果优于自适应模糊PID和普通PID控制的控制效果。     

TRIP steel retained austenite transformation under cyclic V-bending deformation

To investigate the transformation behavior of TRIP steel retained austenite under cyclic load, cyclic V-bending deformation of low carbon Si-Mn TRIP600 was studied by experiment and finite element in this paper. The results showed that, under cyclic V-bending deformation, retained austenite in TRIP steel transformed into martensite gradually with the increasing of bending times, and for the symmetrical characteristic, upper surface and lower surface presented the same transformation tendency. From the first to the fourth V-bending deformatiort, retained austenite volume fraction decreased nearly linearly and then attained saturation step by step. Compressive stress state was helpful for martensite transformation than tension stress state with V-bending deformation, and strain magnitude was the determining factor for retaining anstenite martensitic transformation. With the increasing of bending times effective stress increased and the relationship between maximum effective stress and bending times was nearly linear. Effective stress and effective strain distribution were non-uniform, the maximum effective stress and effective strain were present in the center of the samples. The relationships between retained austenite and V-bending times, and retained austenite with effective strain were set up as Eqs.（1）-（5）. The relationship was typical quadric function, decreased linearly for the initial deformation and attained saturation finally.     

纳米复合永磁材料的交换耦合作用和有效各向异性

以Nd2Fe14B／α-Fe为例，对纳米双相永磁材料软、硬磁性相晶粒间的交换耦合作用和有效各向异性进行了模型化计算，得到软、硬磁性相晶粒间的有效各向异性常数随晶粒尺寸和软磁性相比例的变化关系曲线．结果表明，交换耦合部分采用6种不同函数计算，得到的有效各向异性随晶粒尺寸的变化曲线几乎重合．有效各向异性常数随晶粒尺寸的减小逐渐减小，随软磁性相比例的减小逐渐增大．     

PZT压电陶瓷的应力腐蚀

使用单边缺口拉伸试样对PZT-5压电铁电陶瓷进行恒载荷下的应力腐蚀研究,介质分别为水、甲醇和甲酰胺,结果表明, PzT-5压电陶瓷在这三种介质中均会发生应力腐蚀开裂.归一化应力腐蚀门槛应力强度因子分别为KISCC/KIC=0.66(水),0.73(甲醇)和0.75(甲酰胺).其中断裂韧性:KIC=(1.34±0.25)MPa·m1/2.     

基于序列关联的参差信号分选算法

针对复杂环境下常规直方图信号分选算法对于参差信号分选能力不佳的问题,该文提出一种基于脉冲间隔与单个脉冲关联的直方图算法.该算法根据脉冲间隔与单个脉冲的对应关系建立了脉冲间隔分布矩阵(PIDM),然后通过对PIDM行列的累加计算,得到一种新的直方图,该直方图可避免传统脉冲重复间隔(PRI)变换算法在分选参差信号时对于参差信号帧周期过多抑制的缺陷,且能够通过PIDM对辐射源脉冲串进行序列提取,进而得到参差子序列的周期值.仿真分析结果表明,在不增加计算复杂度的情况下,该算法对存在多部参差辐射源和固定重频辐射源的混合场景仍可保持良好的分选效果.     

OFDM低压电力线通信系统的符号同步及其FPGA实现

为采用FGPA技术可靠实现基于G3-PLC协议的OFDM电力线通信系统的符号同步,推导了符号同步偏差对G3-PLC系统性能的影响。针对传统符号同步算法存在的算法复杂、FPGA实现困难等缺点,根据G3-PLC系统的帧结构,提出了基于训练序列的新的符号同步算法。仿真结果和FGPA实现效果表明,该算法不仅能够有效地实现G3-PLC系统的符号同步,而且运算量小,硬件资源消耗少。     

直接转矩控制中电压矢量对电磁转矩的影响

本文分析了直接转矩控制中电压矢量对电磁转矩的影响,提出了当定子磁链幅值和磁通角(定、转子磁链夹角)变化发生矛盾时,磁通角变化决定转矩变化的传统观点是在一定前提条件下成立的,否则,在某些情况下,转矩的变化与磁通角变化恰恰相反,这导致控制实际效果与开关表设定相反,增大转矩脉动.     

十字形截面钢筋混凝土双向压弯柱正截面承载力的计算方法

通过对8根十字形截面钢筋砼柱在轮向力及双向弯矩共同作用下的反复加载试验研究,揭示了十字形截面钢筋砼双向压弯柱的破坏形态及正找面承载力的一般规律．在此基础上,采用数值达代方法,编制了相应的电算程序,对其受力性能做了进一步的理论分析．最后,提出了十字形截面钢筋砼双向压弯往正截面承载力的计算方法．     

兆瓦级同步风力发电机变桨距控制策略研究

变桨距风力发电机已成为风力发电机组的主要研究和发展方向,结合长星集团同步风力发电机组,对变桨距控制技术进行了研究,在额定风速以下时实行变速运行,控制发电机的励磁电流从而控制发电机的转速,使得风力机转速能够跟随风速变化,保持最佳叶尖速比使系统获得最大的风能利用系数;额定风速以上时,采用PID控制算法控制桨距角,使发电机输出功率恒定,并提出了实现方法;通过仿真工具进行计算机仿真,验证了本方法的有效性。     

Age of Transmission-Optimal Scheduling for State Update of Multi-Antenna Cellular Internet of Things

Timely information updates are critical for real-time monitoring and control applications in the Internet of Things(IoT). In this paper, we consider a multi-antenna cellular IoT for state update where a base station(BS) collects information from randomly distributed IoT nodes through time-varying channel.Specifically, multiple IoT nodes are allowed to transmit their state update simultaneously in a spatial multiplex manner. Inspired by age of information(AoI),we introduce a novel concept of age ...