两种聚丙烯酰胺凝胶银染方法的比较

比较了两种聚丙烯酰胺凝胶的DNA染色方法。对小麦SSR扩增产物的染色结果显示,改进的Bassam银染法颜色背景浅,灵敏度较高,能够看到副带染色。改进的Sanguinetti方法对条带的鉴别力稍差,但因省时省力,成本较低可用于大规模引物筛选时的染色。     

赤眼蜂SSR反应体系的建立

以松毛虫赤眼蜂为试材,研究了单头赤眼蜂DNA的提取方法以及SSR反应体系的的主要成分对SSR扩增结果的影响。结果表明:在20μL PCR反应体系中,Mg2 的最适浓度为2.0mmol.L-1,dNTP的最适浓度为2.0mmol.L-1,引物的最适浓度为0.8μmol.L-1,Taq聚合酶的最适浓度为1.0U。利用此反应体系,对13个松毛虫赤眼蜂地理品系进行SSR反应,用6%变性聚丙烯酰胺凝胶电泳检测PCR扩增产物,不同品系间DNA谱带多态性丰富。     

几种次同步振荡分析方法和工具的阐述

文章地关于次同步振荡的几种工程实用分析方法,如扫频法、复转矩系数法和特征根法进行了比较,提出了作者的看法,最后还利用仿真工具进行了时域分析检验。     

NGH 次同步谐振阻尼方案的研究及仿真分析

针对串联补偿系统次同步谐振（ＳＳＲ）问题的抑制及防止措施,对ＮＧＨ次同步谐振阻尼方案作了详细的理论分析和仿真研究。在论述了ＮＧＨ次同步谐振阻尼方案基本原理的基础上,通过具体算例的仿真分析说明ＮＧＨ次同步谐振阻尼方案对提高暂态转矩稳定和提高有次同步谐振问题系统的稳定性是非常有效的。仿真分析采用电磁暂态计算程序ＥＭＴＰ。     

Review of sub-synchronous interaction in wind integrated power systems: classification, challenges, and mitigation techniques

Emerging sub-synchronous interactions (SSI) in wind-integrated power systems have added intense attention after numerous incidents in the US and China due to the involvement of series compensated transmission lines and power electronics devices. SSI phenomenon occurs when two power system elements exchange energy below the synchronous frequency. SSI phenomenon related to wind power plants is one of the most significant challenges to maintaining stability, while SSI phenomenon in practical wind farms, which has been observed recently, has not yet been described on the source of conventional SSI literature. This paper first explains the traditional development of SSI and its classification as given by the IEEE, and then it proposes a classification of SSI according to the current research status, reviews several mitigation techniques and challenges, and discusses analysis techniques for SSI. The paper also describes the effect of the active damping controllers, control scheme parameters, degree of series compensation, and various techniques used in wind power plants (WPPs). In particular, a supplementary damping controller with converter controllers in Doubly Fed Induction Generator based WPPs is briefly pronounced. This paper provides a realistic viewpoint and a potential outlook for the readers to properly deal with SSI and its mitigation techniques, which can help power engineers for the planning, economical operation, and future expansion of sustainable development.     

多站询问对邻近二次雷达的影响及其对策

为解决二次雷达站密集区域的相互异步干扰问题,分析了多站询问对邻近二次雷达的干扰因素;提出了异步干扰式窜扰的概念,推导出对应的概率公式;提出了参差改变询问重复频率或自适应改变询问重复频率、应答处理器采用滑窗过滤等解决方案;最后给出了简易二次雷达使用中的对策.对于采用同频率询问/应答机原理工作的装备具有借鉴意义,适用于雷达站架设较密集区域的应用环境.     

On‐off discrete control of series capacitors for power system stability with torsional oscillation countermeasure

Application of controlled series capacitors with antiparallel thyristor combination across the capacitor segment is a new and promising countermeasure for enhancement of power system stability. The line reactance can be directly controlled by the controlled series capacitors; hence, it is very effective to apply the capacitors for damping power system disturbances. However, the segmented series capacitors may cause subsynchronous resonance (SSR) that can lead to turbine‐generator shaft failure and electrical instability at oscillation frequencies lower than normal system frequency as well as the conventional capacitor may cause. In this paper, we describe the following. (1) The response of turbine‐generator shaft torque is analytically discussed when the number of inserted series capacitors in the power system is changed. (2) It is proposed for SSR countermeasure that the control system will be designed to avoid the number of series capacitor segments which may cause SSR in addition to selecting better on‐off timing of series capacitors. (3) The effects of the proposed countermeasures are confirmed by the results of EMTP simulations using both simplified two‐mass shaft model and detailed five‐mass shaft model of turbine‐generator. © 1999 Scripta Technica, Electr Eng Jpn, 128(3): 31–42, 1999     

空调器固体继电器的选用

介绍了空调器固体继电器的基本特性,以及应用选型、布局和在应用中应采取的保护措施,以实现固体继电器在使用中的可靠性。     

380 kt/a硫磺回收装置设计特点及试车总结

380kt/a硫磺回收装置是中化泉州石化有限公司12 000kt/a炼油项目的配套环保装置,采用国内自行研发的先进硫磺回收技术进行设计和试运行。简要介绍了该大型硫磺回收装置的设计特点及工艺流程,并对在开工试运行期间低负荷工况下出现的问题进行了分析总结,可为装置长周期平稳运行提供指导。试车结果表明:硫磺回收装置运行平稳,尾气中SO2的排放量符合国家环保部门的规定,生产的硫磺成品质量达到GB/T 2449-2006《工业硫磺》中规定的优等品级别,具有较好的环保效益和经济效益。     

基于PSCAD/EMTDC的多机系统次同步谐振分析策略

介绍了采用国际著名电磁暂态仿真软件PSCAD/EMTDC对多机系统次同步谐振进行分析时主要用到的两种方法:基于时域仿真实现的复转矩系数法-测试信号法,时域仿真法.对于多机系统应用PSCAD/EMTDC进行SSR分析时,针对同型同负载、同型不同负载多机系统以及不同型多机系统等情况,分别可以采用相应分析方法,以达到预想的效果;将两种分析方法各自的优、缺点进行了分析对比.