基于状态反馈精确线性化变结构控制的SSSC控制器设计

提出一种基于状态反馈精确线性化变结构控制的静止同步串联补偿器(SSSC)控制器设计方法.考虑到SSSC交流侧电压幅值和相角以及直流侧电容电压的动态调节过程,建立了SSSC在同步旋转dq坐标系下的非线性数学模型,在此模型的基础上,采用状态反馈精确线性化方法将原非线性系统转化为线性系统.然后,应用变结构控制原理设计SSSC控制器,同时通过PI控制稳定直流侧电容电压.最后,利用MATLAB仿真软件搭建了装设有SSSC的110kV输电系统的仿真模型,仿真结果表明了所设计的控制器能够很好地根据需求来改善电网输电能力,具有良好的暂态控制性能.     

基于不同故障情况的特高压变压器差动保护仿真研究

介绍了当前中国在建的特高压变压器的结构和参数,并建立了相应的动态仿真模型。根据特高压变压器的结构和运行特性,提出了针对特高压容量大,分体式结构的差动保护配置。通过模拟不同故障情况下差动保护的反应,对各种差动保护的灵敏性进行分析比较。仿真结果表明单独对调压绕组和补偿绕组分别配置差动保护能提高其匝间故障的灵敏性,故障分量差动保护可以提高重负荷情况下变压器内部发生轻微故障的灵敏性,分侧差动保护则可以避免励磁涌流和过励磁的影响,零序差动保护可以提高单相接地故障保护的灵敏性,尤其是接地点离中性点很近的轻微接地故障。     

Antiviral Effects of ABMA and DABMA against Influenza Virus In Vitro and In Vivo via Regulating the Endolysosomal Pathway and Autophagy

Influenza virus is an acute and highly contagious respiratory pathogen that causes great concern to public health and for which there is a need for extensive drug discovery. The small chemical compound ABMA and its analog DABMA, containing an adamantane or a dimethyl-adamantane group, respectively, have been demonstrated to inhibit multiple toxins (diphtheria toxin, Clostridium difficile toxin B, Clostridium sordellii lethal toxin) and viruses (Ebola, rabies virus, HSV-2) by acting on the host’s vesicle trafficking. Here, we showed that ABMA and DABMA have antiviral effects against both amantadine-sensitive influenza virus subtypes (H1N1 and H3N2), amantadine-resistant subtypes (H3N2), and influenza B virus with EC₅₀ values ranging from 2.83 to 7.36 µM (ABMA) and 1.82 to 6.73 µM (DABMA), respectively. ABMA and DABMA inhibited the replication of influenza virus genomic RNA and protein synthesis by interfering with the entry stage of the virus. Molecular docking evaluation together with activity against amantadine-resistant influenza virus strains suggested that ABMA and DABMA were not acting as M2 ion channel blockers. Subsequently, we found that early internalized H1N1 virions were retained in accumulated late endosome compartments after ABMA treatment. Additionally, ABMA disrupted the early stages of the H1N1 life cycle or viral RNA synthesis by interfering with autophagy. ABMA and DABMA protected mice from an intranasal H1N1 challenge with an improved survival rate of 67%. The present study suggests that ABMA and DABMA are potential antiviral leads for the development of a host-directed treatment against influenza virus infection.     

Online combinatorial based mechanism for MEC network resource allocation

In this paper, the resource allocation problem for mobile edge computing (MEC) network is discussed. We focus on the design of online resource allocation strategy by considering the time‐varying demands of the combinatorial resources for the mobile users. To handle this issue, at first, a time splitting‐based online allocation mechanism is introduced. Then, for a given resource allocation period of the time splitting, a combinatorial auction mechanism for the combination resources allocation is proposed. We further prove that the proposed combinatorial auction is both individual rational and incentive‐compatible, and which can bring a higher revenue to the service provider. In order to verify the performance of the proposed mechanism, a variable‐relaxed‐based performance‐bound algorithm and a greedy optimization‐based suboptimal algorithm are presented for comparison purpose. Finally, the performance of these proposed algorithms are testified by numerical simulations, which confirm the analysis results.     

一种基于维度加权盲K近邻算法的数字预失真技术

传统的数字预失真(DPD)模型通常在所有的输入信号功率上采用单一多项式模型和单一记忆深度对功率放大器(PA)进行线性化矫正。然而,功率放大器在不同的功率水平下会呈现出不同的非线性特性,并产生不同的记忆效应。针对这一问题,该文提出一种基于维度加权盲K近邻(KNN)算法的数字预失真模型,所提模型根据功放当前输入信号以及记忆输入信号的幅度进行维度加权的KNN分类,组成维度加权盲KNN记忆多项式(WKMP)模型,并为每一类输入信号序列建立子模型。所提方法用Doherty功率放大器进行实验验证,使用带宽为30 MHz、频点为2.2 GHz的3载波长期演进(LTE)信号作为输入,反馈端使用122.88 MHz的采样率进行采样。实验结果表明,所提维度加权盲KNN分类方法与记忆多项式(MP)模型结合时,功放正向建模效果和数字预失真效果均超过了广义记忆多项式(GMP)模型,并远超记忆多项式模型的效果,实验结果验证了所提模型的优良性能。     

关于变频涡旋压缩机动盘运转稳定性探究

在涡旋压缩机设计过程中,确保动盘稳定运转是设计中核心技术点之一.为更准确的计算动盘运转稳定性,以某型号的涡旋压缩机为研究对象,结合压缩机实际运转过程,分析动盘受力特性;推导出动盘运转稳定性计算的理论数学模型,将复杂的动盘运转稳定性问题转化为止推反力作用点的求解问题.通过试验掌握了背压与转速之间的线性关系,进一步完善全频...     

A Rapid and Sensitive Method for Semicarbazide Screening in Foodstuffs by HPLC with Fluorescence Detection

Food Analytical Methods - Semicarbazide (SEM) has been proven to extensively exist in foodstuffs due to anthropogenic factor in food processing and possesses various toxic effects on human health....     

在任意位置激振时周期简支梁的功率流

本文进一步研究周期简支梁在力激振时的振动功率流,分析激振位置对振源向梁输入功率流和沿梁传播功率流的特点。在不同传播域中可适当调整振源位置从而减少输入功率流,但是不管在何点激振,沿梁正向和沿梁反向传播的功率流相等,且等于输入功率流的一半。文中还讨论结构阻尼对减少输入功率流和传播功率流的作用,阻尼在奇数传播域界频率处有效地控制输入功率流,而在传播域中有效地损耗传播功率流。     

120路簇射计数器读出电子学系统

120路簇射计数读出电子学系统,主要由采样保持电路、多路模拟数字转换器及模拟总线组成。为了提高整个系统的装配密度和可靠性并减小环境温度变化的影响,专门设计了一种薄膜混合集成采样保持电路。采用了计算机在线校正方法,解决了放大器增益变化、积分非线性、模拟开关台阶和传输电缆干扰等引起的测量误差问题。系统的主要指标为:线性优于0.2％,σ噪音约为1.3BADC道,串扰优于1％,Z向位置分辨优于0.6％(SQS簇射计数器模型)。