普通烟草种质资源的SSR标记与指纹图谱分析

利用SSR标记构建了烟草核心种质中80份普通烟草种质的指纹图谱。从286对SSR引物中筛选出8对多态性较好的引物,对这些烟草种质进行分析,共检测到85个多态性位点。研究表明,这8对多态性SSR引物可以将80份烟草种质完全区分开,每份种质都有各自独特的指纹图谱,表明SSR标记完全适用于普通烟草种质鉴定和指纹图谱构建工作。     

Claus尾气加氢催化剂活性衰减的原因分析及改进措施

针对中化泉州石化有限公司硫磺回收装置Claus尾气加氢催化剂活性快速下降的情况,分别从积硫、积炭、水热老化、硫酸盐化、催化剂预硫化不完全或失硫、沟流等方面分析了引起催化剂活性下降的原因,并提出了相应的判断依据及恢复催化剂活性的对策。结果表明,催化剂活性快速下降的主要原因是加氢反应器的气体分布器设计不合理,造成过程气在加氢反应器内未均匀分布,另外,由于加氢反应催化剂堆密度较低,装置在较高负荷下发生了沟流;通过对加氢反应器的气体分布器的开口进行部分封堵及在加氢催化剂上部敷设瓷球防护层等措施,有效抑制了沟流的发生,稳定了催化剂活性,保证了装置高负荷稳定运行。     

RAPD and SSR Polymorphisms in Mutant Lines of Transgenic Wheat Mediated by Low Energy Ion Beam

Two types of markers-random amplified polymorphic DNA （RAPD） and simple sequence repeat DNA （SSR）-have been used to characterize the genetic diversity among nine mutant lines of transgenic wheat intermediated by low energy ion beam and their four receptor cultivars. The objectives of this study were to analyze RAPD-based and SSR-based genetic variance among transgenic wheat lines and with their receptors, and to find specific genetic markers of special traits of transgenic wheat lines. 170 RAPD primers were amplified to 733 fragments in all the experimental materials. There were 121 polymorphic fragments out of the 733 fragments with a ratio of polymorphic fragments of 16.5%. 29 SSR primer pairs were amplified to 83 fragments in all the experiment materials. There were 57 polymorphic fragments out of the 83 fragments with a ratio of polymorphic fragments of 68.7%. The dendrograms were prepared based on a genetic distance matrix using the UPGMA （Unweighted Pair-group Method with Arithmetic averaging） algorithm, which corresponded well to the results of the wheat pedigree analysis and separated the 13 genotypes into four groups. Association analysis between RAPD and SSR markers with the special traits of transgenic wheat mutant lines discovered that three RAPD markers, sl, opt- 16, and f14, were significantly associated with the muticate trait, while three SSR markers, Rht8 （Xgwm261）, Rht-Blb, and Rht-Dlb, highly associated with the dwarf trait. These markers will be useful for marker-assistant breeding and can be used as candidate markers for further gene mapping and cloning.     

Smith-Waterman算法在脉动阵列上的实现及分析

Smith Waterman算法是一种经典的序列比对算法 ,在双序列比对的情况下具有比较好的性能 ,但是在大规模的序列比对时 ,其性能并不能令人满意 .脉动式阵列和Smith Waterman算法有比较好的吻合性 .该文通过在龙芯 1号处理器上附加一个脉动式阵列的协处理器 ,构建了硬件模型 .通过模拟器的验证 ,附加了协处理器的龙芯 1号的性能与没有附加协处理器时的性能之比接近于线性 .该文最后根据硬件模型和模拟器的性能数据 ,具体分析了系统各个方面对性能提高的影响     

大规模双馈风电场次同步谐振的分析与抑制

已有的运行经验表明,风电场接入含有固定串补的系统时,存在诱发次同步谐振(SSR)的风险.因此,有必要对风电场发生SSR现象的机理做深入分析,以便提出相应的抑制措施.文中首先根据国内某地区风电场的实际参数建立了应用于SSR分析的等值模型,通过仿真呈现了该模型发生SSR的情形;然后,利用特征值法分析了风速、并网风力发电机台数以及双馈感应发电机(DFIG)控制参数等对系统SSR频率和阻尼特性的影响;并进一步推导了等值模型用于SSR分析的等效电路,详细分析了风速、发电机台数和DFIG控制参数等影响SSR特性的机理;综合所有的分析指出,风电场的SSR现象与轴系扭振无关,是一种特殊的电气谐振.最后,提出了抑制风电场SSR的方案,并通过仿真和特征值分析进行了验证.     

基于近似熵的次同步谐振检测方法

提出了一种可实时检测次同步谐振（sub-synchronous resonance,SSR）的方法。首先采样电流信号,计算其近似熵（approximate entropy,ApEn）;然后在连续时间区段上,观察近似熵的变化规律判断是否发生次同步谐振,还分析了近似熵的实时性、很好的抗干扰能力以及同时处理随机信号和确定性信...     

典型FACTS元件抑制次同步谐振研究综述

由串联电容补偿引起的电力系统次同步谐振（SSR）是1种恶性事件,必须有效地加以抑制。FACTS技术是1种新型的、重要的抑制SSR的手段。在概要介绍次同步谐振的背景后,分别阐述各种典型FACTS元件抑制SSR的机理及性能,然后探讨FACTS元件用于抑制SSR时控制器的设计方法及相关问题,随后讨论用于分析FACTS元件抑制SSR的方法所具有的特点,最后对本课题的研究前景加以展望。     

TCSC抑制次同步谐振的机理研究及其参数设计

正确地分析TCSC频率阻抗特性是评价TCSC抑制SSR能力的基础。该文给出了考虑导通角变化的三维频率阻抗图,该图清晰地表明:当目标导通角小于临界导通角时,TCSC低频阻抗特性存在一个容性曲面,只有越过临界导通角后低频视在阻抗才表现为感性。基于IEEE第一基准模型的数字仿真分析验证了频率阻抗计算方法和结果的正确性,深入阐明了TCSC抑制SSR的物理机理以及要实现完全抑制SSR需满足的工作条件。在此基础上还讨论了TCSC主电路的参数设计原则,使得TCSC不仅能满足工频基波阻抗调节特性的要求,而且能最大限度地提高对SSR的抑制能力。     

Genetic Diversity and Population Structure of Broomcorn Millet (Panicum miliaceum L.) Cultivars and Landraces in China Based on Microsatellite Markers

Broomcorn millet (Panicum miliaceum L.), one of the first domesticated crops, has been grown in Northern China for at least 10,000 years. The species is presently a minor crop, and evaluation of its genetic diversity has been very limited. In this study, we analyzed the genetic diversity of 88 accessions of broomcorn millet collected from various provinces of China. Amplification with 67 simple sequence repeat (SSR) primers revealed moderate levels of diversity in the investigated accessions. A total of 179 alleles were detected, with an average of 2.7 alleles per locus. Polymorphism information content and expected heterozygosity ranged from 0.043 to 0.729 (mean = 0.376) and 0.045 to 0.771 (mean = 0.445), respectively. Cluster analysis based on the unweighted pair group method of mathematical averages separated the 88 accessions into four groups at a genetic similarity level of 0.633. A genetic structure assay indicated a close correlation between geographical regions and genetic diversity. The uncovered information will be valuable for defining gene pools and developing breeding programs for broomcorn millet. Furthermore, the millet-specific SSR markers developed in this study should serve as useful tools for assessment of genetic diversity and elucidation of population structure in broomcorn millet.     

加热炉自动温度控制系统改造

在分析原加热炉温度控制回路设计缺陷的基础上，介绍了通过引进先进设备和PLC控制技术实现技术改造的过程，并阐述了其硬件电路图和PLC控制程序。