计及电网停电风险的输电线路动态融冰决策方法

电网发生大面积冰灾情况时,多条输电线路存在覆冰故障隐患,电网稳定运行受到严重威胁,需要提前制定输电线路融冰方案,合理安排融冰顺序。针对此问题,分析输电线路覆冰继续运行给电网带来的停电风险,将与待融冰输电线路相关联的变电站的电气主接线展开,将传统削负荷模型改进后应用于输电网与变电站主接线的组合网络,建立断路器可靠性模型,计算靠后融冰线路因继续运行的电网停电风险;利用计及风速及降雨影响的输电线路覆冰增长预测模型,计算输电线路的覆冰率,根据覆冰率门槛值确定待融冰线路集,基于覆冰严重度模型构建系统全局的覆冰指数指标;综合考虑电网停电风险及系统全局覆冰指数建立输电线路融冰紧迫度指标,动态更新待融冰线路并决策融冰顺序。最后,以IEEE RBTS系统进行算例分析,验证了所提方法的可行性与合理性。     

DOF转录因子AtDof1.7 RNA干扰载体的构建及拟南芥的遗传转化

DOF (DNA binding with one finger)转录因子是植物特有的转录因子家族,含有一个独特的富含Cys残基的单锌指DNA结合区域,在植物生长发育中参与多种生物学过程。本研究根据拟南芥AtDof1.7基因(GenBank登录号为AT1G51700)序列设计含有不同酶切位点的特异性扩增引物,以拟南芥总DNA为模板,扩增AtDof1.7基因片段,将AtDof1.7基因正向反向分别插入表达载体的相应位置,构建成AtDof1.7基因的RNA干扰载体pADOF1。利用改良的floral-dip方法将干扰载体pADOF1成功转入野生型拟南芥,经草甘膦抗性筛选和PCR检测获得5株阳性转基因植株。利用RT-PCR技术和气相色谱法分别分析了AtDof1.7基因的表达和种子脂肪酸组成,结果表明5株转基因植株中AtDof1.7基因的表达量不同程度低于野生型植株,种子油酸含量明显上升,亚麻酸含量明显下降,说明AtDof1.7转录因子与拟南芥种子脂肪酸代谢途径有一定的关系,为进一步研究其在脂肪酸代谢过程中的调控作用以及在油菜中研究该类转录因子的功能奠定了基础。     

基于Adaboost算法的输电线路舞动预警方法

输电线路舞动是目前尚未被全面准确认识的世界性难题,已严重威胁输电系统的安全稳定运行。文章分析影响舞动的外界气象环境因素,并在此基础上提出一种基于Adaboost集成学习算法的输电线舞动预警方法。采用基于Gini指标的决策桩作为弱分类器,通过对多个弱分类器的训练及加权求和,输出舞动预测结果及其置信度,可为电网运维人员提供决策支撑。最后,使用历史数据进行验证性实验,结果证明了所提方法的有效性。     

诱导Paracin1.7生成的刺激因子的分离与纯化

旨在分离纯化枯草芽孢杆菌(Bacillus subtilis)中能够诱导细菌素Paracin1.7分泌的刺激因子,并探明其对副干酪乳杆菌(Lactobacillus paracasei) HD1.7细菌素生成量及群体感应相关基因luxS表达的影响。本研究通过60%硫酸铵沉淀、CM Sepharose Fast Flow弱阳离子交换柱层析中度纯化及Superdex 75凝胶层析精度纯化,将获得的层析分离物与L. paracasei HD1.7共培养,检测共培养发酵液的抑菌活性及luxS基因的转录水平,并用SDS-PAGE与Native-PAGE检测分离物质。结果表明L. paracasei HD1.7抑菌活性为126.68%;luxS基因上调表达,为对照菌株的2.43倍;刺激因子的表观分子量约为30 kDa。本研究利用三步法初步分离纯化出诱导Paracin1.7生成的刺激因子,明确该刺激因子可以启动种间群体感应相关基因luxS,为L. paracasei HD1.7的群体感应研究奠定了理论和技术基础。     

改进粒子群算法的自动阻抗匹配技术

由于无线电能传输距离的改变或谐振线圈之间发生偏移、负载改变等多方面的影响使系统的输入阻抗发生变化,导致输入阻抗与射频源内阻不匹配,使传输效率大幅下降。在射频源和发射线圈之间加入阻抗匹配网络可以提高无线电能的传输效率。为了提高阻抗匹配的精度和速度,提出了一种改进的粒子群算法。重点将改进算法和传统算法进行仿真实验比较,证明了改进算法在匹配精度和速度方面的优越性。最后将该算法嵌入到自动阻抗匹配系统中,提高了无线电能的传输效率,同时证明了所提算法的有效性。     

稻瘟病监测预测方法研究现状及流行风险评估体系构建初探

稻瘟病是水稻生产上最主要的病害之一,对稻瘟病的发生流行状况进行准确的监测预测是有效防治病害的前提和基础。分析了应用菌源信息、气象因子信息和水稻冠层光谱信息3个方面对稻瘟病监测预测的国内外研究现状,总结了现有监测预测方法存在的主要问题和技术难点,从系统研究的角度出发,提出了应用与稻瘟病发生相关多源信息构建病害流行风险评估体系的研究思路。提出的稻瘟病监测预测方法可提高病害的监测预测精度,同时也对其他病害监测预测的理论和方法具有重要的借鉴作用。     

影响宝天高速公路视程障碍的天气现象分布特征

为了做好宝天高速公里的气象保障工作,笔者运用1961-2008年天宝高速公路宝鸡、麦积国家气象站视程障碍天气观测资料,分析视程障碍天气现象对公路正常运行的干扰及天气现象本身的时空分布特征及变化趋势。结果表明,沙尘暴属小概率事件。近年来,沿公路从东向西雾日逐渐减少,浮尘及扬沙日数逐渐增加。10月份,全线路出现雾天的频率较高,为0.56天/年;浮尘及扬沙主要出现在3-5月,全线路出现浮尘频率为1.4天/年,扬沙频率为0.7天/年。雾日宝鸡以0.34天/年线性趋势减少,天水以0.01天/年线性趋势减少;浮尘宝鸡以0.41天/年线性趋势减少,天水以1.37天/年线性趋势减少;宝鸡自2002年以后,已连续7年无扬沙天气出现,天水扬沙线性减少趋势为0.37天/年。应根据视程障碍天气现象变化规律,制定应对措施,做好气象保障服务。     

辽宁省松毛虫发生面积气象预报方法研究

为了利用气象因子预测松毛虫的发生面积,基于辽宁省阜新县1983—2008年气象资料与松毛虫发生面积等资料进行相关分析,将筛选出的气象因子作为预报因子,通过多元回归法和人工神经网络法对松毛虫发生面积进行模拟和预测。结果表明,与松毛虫发生面积显著相关的5个气象因子包括：上一年12月平均最低温度、上一年11月平均相对湿度、上一年9月降水量、本年2月降水量和本年3月降水量;人工神经网络法的模拟和预测精度均优于多元回归法,多元回归法的预测精度58.2%,人工神经网络法的预测精度为83.6%;人工神经网络法更适用于辽宁地区松毛虫发生面积的预报。     

基于GRNN算法的潜在产出与产出缺口估算模型

基于神经网络学习性、非参数估计的优势,建立估算经济潜在产出和产出缺口的广义回归神经网络（GRNN）模型,对中国产出缺口和潜在产出增速的1978—2015年数据进行估算、2016—2020年数据进行多步预测,实证分析较好地克服了生产函数法中由于事先假设确定的函数形式及选择不同函数结果不同的问题,并且所估算的潜在产出增速与经济增速具有较高的契合度。模型分析得出：中国经济增长速度大致维持在潜在产出增长率水平附近,便可实现通货膨胀率维持在合理水平,且较好地实现总体供需平衡的目的。     

副干酪乳杆菌HD1.7遗传转化体系的初步建立

优化副干酪乳杆菌(Lactobacillus paracasei)HD1.7的电转化条件,为构建L .paracasei HD1.7prcR基因敲除突变株奠定基础。通过电转化方法将自杀质粒pUC18-prcR-tet导入L. paracasei HD1.7内,对影响L .paracasei HD1.7电转化的几个主要因素进行了初步研究。当L. paracasei HD1.7生长8 h时,加入青霉素使终浓度为12.5 μg/mL,再培养1 h。经AEB1电转缓冲液(蔗糖浓度为0.3 mol/L)处理后,在1.8?2.0 KV电压下完成电击,并迅速加入MRS培养基中,复苏5 h,成功地将自杀质粒pUC18-prcR-tet转入L. paracasei HD1.7内,并发生了部分同源重组。本研究得到了副干酪乳杆菌（Lactobacillus paracasei）HD1.7较优电转化条件,为继续研究L.paracasei HD1.7的群体感应调控因子prcR奠定了基础。     

Fast modeling of the motor broadband equivalent circuit model

This paper proposes a modeling method of the motor broadband equivalent circuit model. The impedance amplitude-frequency characteristics of the motor terminal through measuring are obtained. The impedance amplitude-frequency characteristics are devided into several regions based on its first resonant point information,and the motor broadband circuit topology is developed with each region equaling a resonance unit. The RLC parameters of resonance unit are extracted through frequency and corresponding impedance of the any non-resonant and resonant point in each unit. This proposed method is used to build DC and AC motor broadband equivalent circuit model. Their impedance amplitude-frequency characteristics are simulated by the Saber software. The measurement results and the simulation result of references are compared. The DC motor simulation results coincide with the measurement results in 0.1~50 MHz,and the AC motor is in 0.1~40 MHz. The results show that the motor broadband circuit model is reliable and feasible.     

The optical isolation method of suppressing electromagnetic interference of automotive ignition system

Electromagnetic radiation, which is caused by the engine ignition system, is the most powerful electromagnetic interference (EMI) source in the vehicles, as well as the main reason of most electronic control unit (ECU) malfunction. In order to reduce interference from ignition noise on ECU, we use optical isolation technology to isolate electrical connections between the interference source and the control circuit. The formation mechanism of the ignition system EMI is analyzed. The possibility of suppressing ignition system EMI with optical isolation technology is discussed. Then, as a result we design an experimental platform of suppressing ignition system EMI. The experimental results show that the effect of suppressing ignition noise, in 20~100 MHz frequency band, is obvious after applying optical isolation circuit. It can address the issue of automotive EMC.     

The study on EMI principle and suppression method of vehicle ignition system

Vehicle ignition system is the main electromagnetic interference source. Electromagnetic radiation produced by ignition system will produce the interference to electromagnetic environment around. It is necessary to study the electromagnetic interference (EMI) principle, noise paths and suppression method. We analyze the electromagnetic interference principle of ignition system, and harness trouble-shooting related to electromagnetic interference is also tested. Results show that the spark discharge between spark plug electrodes is the main interference source in ignition system. Then, the paths of conducted interference and the reason of radiated emission are discussed in detail. Finally, two kinds of power supply cord EMI filters are designed and implemented on the basis of analysis results. Experimental results indicate that the filter can reduce the noise of power-wire in broadband range. Simultaneously, the radiation emission performance from power wire is also reduced observably. The proposed mixing filter has been demonstrated in this paper to perform satisfactorily with excellent effectiveness in suppression of conducted EMI from 10 MHz to 110 MHz, and the object car can also pass the EMC standard tests.     

LCL型CPT系统的参数设计方法及频率特性分析

以金鲳鱼为原料,固定小麦粉与水的质量比为2∶1,食盐添加量2%,微波真空度0.095 MPa,在单因素试验的基础上,通过正交试验对微波真空技术膨化鱼糜饼工艺条件进行优化。结果表明,鱼糜饼制作的最佳工艺条件为:鱼糜含量35%,膨化温度100℃,膨化时间20 min,鱼糜饼厚度2 mm,在该工艺条件下,制得的膨化鱼糜饼色泽金黄、质地酥脆、风味清香,成品膨化率可达到540%。     

The Analysis of Abnormal State for Power Distribution Network Based on MATLAB

Along with the extensive use of power cable lines in power distribution system, the probability of fundamental frequency resonance has greatly increased. It may endanger the security operation and power supply reliability of the power system. On the basis of theoretical analysis and numerical calculations using MATLAB language combined with a real instance, it is indicated that the improper electrical parameter coordination caused by the abundance of power cable lines result in fundamental frequency current resonance, in addition, the countermeasures based on SVC to solve the problem are put forward. Further more, digital simulations have been carried out in detail based on the dynamic simulation model developed by the application of MATLAB/Simulink and its power system simulation software. Simulation results proves the effectiveness and practicability of the scheme presented.     

Composite structure of sterilization and descaling system for circulating cooling water

In order to resolve the hazard of biofouling and scale in circulating cooling water system of power stations, this paper takes the lead in combining high voltage pulses and high frequency pulses for sterilization and descaling process. It analyzes both electromagnetic effects and biochemical effects on sterilizing and descaling process caused by the high voltage pulses and high frequency pulses respectively. The pulse generator is designed according to the requirements of electromagnetic parameters for effective operation. The design and improvement of process chambers are assisted by electromagnetic field simulation technology. Experimental data prove that the system can output high voltage pulse whose maximum peak value reaches 7 kV and high frequency pulse whose maximum peak value reaches 100 V the frequency ranges from 500 kHz to 2 MHz. The rate of sterilization can be as high as 91,and the rate of descaling reaches 71. This system is expected to achieve the standards of industrial water treatment through further research.     

Numerical Prediction of Frequency of Delaminated Advanced Grid Stiffened plate

The paper aims to investigate natural frequency of delaminated advanced grid stiffened composite plates by hump resonance method.The composite laminated plate element and the rib element are adapted to simulate the laminated plate and the ribs.Based on the composite laminated plate and beam element model considering first-order shear effect,a damping model on the basis of Rayleigh damping model in conjunction with Adams' strain energy method(MSE) and a Hertz nonlinear dynamic contact model to avoid the overlap and penetration phenomenon between the upper and lower sub-laminates at the delaminated region.A numerical analysis method of dynamic response for the delaminated composite plates is carried out by precise time-integration method,and then the natural frequencies are achieved when the dynamic deflections reach the hump peak.For the frequency-domain analysis provided in the former research papers,it is a difficult problem to avoid the embedded phenomenon in the mode shapes at the delamination zone,while in the current time-domain analysis,the embedded phenomenon can be successfully overcome by using nonlinear contact model.By vibration excitation test,the specimens were excited by different excited frequency and the amplitude frequency response characteristics obtained are used to extract the frequency.The extracted frequencies of the narrow delaminated composite plates measured,which agrees well with the predicted natural frequencies.     

Novel Power Supply Method and Technology Analysis for Electrified Monorail System

The problems of industry monorail conveying system brought by tradition physical contact such as irregular contact spark, carbon laydown and unsafe, narrow the area which the material handling system can apply to in awful industry environment, e.g. forge, cleaning, lacquering. A novel monorail power supply method based on electromagnetic coupling theory is presented. Discussions are made on several problems such as frequency selection, load control, efficiency elements and harmonic effects at the same time. Moreover, solutions are brought about according to them. The monorail application of this technology provides clean, stable and safe power supply, and immunes to environment interference such as dust, water as well.     

Comparative study of aircraft three-phase power factor corrections

This paper summarizes the requirements of standards for aircraft power supply firstly,and then points out that the input current harmonic and output DC voltage ripple should be considered seriously when designing three-phase power factor correction (PFC)for aircraft under variable line frequency and unbalanced line supply. Based on reviewing the topologies for aircraft three-phase PFC,three typical topologies,i.e. three-phase pulse width modulation (PWM)rectifier,traditional shunt active power filter (APF)and generalized APF,are picked up. A unified single-phase equivalent model is developed for comparing the harmonic suppression performance of the three active PFC schemes. And the switching stress is also calculated for evaluating their efficiency and power density. Three 5 kW PFC are designed by employing each of the three selected schemes. Simulation is carried out to verify the correctness of the theoretical analysis. The theory and simulation results indicate that the generalized APF topology shows the most technical merit for aircraft three-phase PFC. Future research works on generalized APF are also pointed out,which are solving the uncontrollability of its DC output voltage and optimal designing the filter inductors.     

B-SPLINE FINITE ELEMENT METHOD IN GENERAL 2-D FIELD REGIONS

A B-spline finite etement method for solving general 2-D electromagnetic field problems is established. The B-spline bases for a general field region are constructed using the Bspline interpolation functions defined on a rectangle which contains the region. The Dirichlet boundary condition is dealt with by means of the generalized variational principle. Two numerical examples are given that show the characteristics and practical value of the method.