压水堆燃料组件流致振动关键技术研发及应用

燃料棒包壳磨损是燃料组件设计中最关注的现象,流致振动引起的燃料棒与格架间的微动磨损是造成燃料棒失效的一个重要原因.采用理论分析、数值模拟与程序开发相结合的方式,完成了压水堆燃料组件流致振动及其诱发的微动磨损的分析评价方法与关键技术研发.首先,基于有限元方法建立燃料棒—格架支撑相互作用的振动分析模型,获得了燃料棒的动态特性,并为专用分析程序提供关键输入参数;其次,利用随机振动理论,从经受湍流作用的薄圆柱体振动响应的理论分析出发,针对湍流激励、流弹失稳和漩涡脱落3种流致振动机理,建立了燃料棒振动响应的理论模型,基于振动分析得到的响应和ARCHARD公式,建立了燃料棒的微动磨损分析模型,并开发了专用程序;最后,完成了燃料棒流致振动及微动磨损的工程应用,形成了一套评价压水堆燃料棒流致振动与微动磨损行为的分析方法与分析工具.     

关于一类矩阵的平方根公式

从性质C1/2C1/2=C出发,在不求过渡矩阵的前提下,利用Sherman-Morrison公式得到了非负定矩阵A=aaT+bbT的平方根表示,进而解决了一类特殊矩阵方程X2=A的求解问题.其中a,b是Rn中的n维非零列向量.     

试题库系统的设计

主要讨论运用Structs架构,数据库用SQLServer2005,其之间数据以XML传递。通过此方法,能很好的实现程序、试卷数据库和样式分离,同时,具有十分友善的界面。可以灵活的输出各种格式的试卷,利于学生们的学习,同时,方便教师的教学。     

Complete genome sequence of Salmonella enterica serovar Typhimurium LT2.

Salmonella enterica subspecies I, serovar Typhimurium (S. typhimurium), is a leading cause of human gastroenteritis, and is used as a mouse model of human typhoid fever. The incidence of non-typhoid salmonellosis is increasing worldwide, causing millions of infections and many deaths in the human population each year. Here we sequenced the 4,857-kilobase (kb) chromosome and 94-kb virulence plasmid of S. typhimurium strain LT2. The distribution of close homologues of S. typhimurium LT2 genes in eight related enterobacteria was determined using previously completed genomes of three related bacteria, sample sequencing of both S. enterica serovar Paratyphi A (S. paratyphi A) and Klebsiella pneumoniae, and hybridization of three unsequenced genomes to a microarray of S. typhimurium LT2 genes. Lateral transfer of genes is frequent, with 11% of the S. typhimurium LT2 genes missing from S. enterica serovar Typhi (S. typhi), and 29% missing from Escherichia coli K12. The 352 gene homologues of S. typhimurium LT2 confined to subspecies I of S. enterica-containing most mammalian and bird pathogens-are useful for studies of epidemiology, host specificity and pathogenesis. Most of these homologues were previously unknown, and 50 may be exported to the periplasm or outer membrane, rendering them accessible as therapeutic or vaccine targets.     

京沪高速铁路北京至沧州段桥梁工程施工与创新

针对京沪高速铁路北京至沧州段桥梁工程特点，重点介绍了代表性特殊结构桥梁的施工方法、区域性地面沉降地区桥梁工后沉降的控制措施，以及保证350 km/h无砟轨道高平顺性的施工技术创新措施。     

论数字控制系统中采样频率的选定

合理选择采样频率是设计实时数字控制系统遇到的实际问题。而采样频率的选定是实现高精度，良好指标和具备较强抗扰力控制的关键所在，根据实际经验讨论了选定采样频率的主要参量和方法。     

The Pile Static Loading Test of Jinfeng Bridge in Shantou City

通过对金凤大桥31#墩桩基静荷载试验,查明桩基的安全储备,推求其计算参数,测定其钻孔灌注桩各土层的桩侧极限摩阻力及桩尖反力,为最终确定桩基承载力提供依据.     

基于在场价值提升的高校课堂吸引力重构研究

大学课堂是高校教育的前沿阵地,因此大学课堂缺乏吸引力势必会影响课堂实践、师生和谐和教育的良性循环。针对部分教师、学生的不作为及高等教育机制和体制的弊端,应从提升师生的在场价值出发,重构大学课堂吸引力。一是从根本上扭转教学为辅的高等教育体制;二是打破教师主导课堂的传统模式,创新教师—学生的互动模式,构筑"多联、互动、发展"的课堂和"教师—学生—高校—社会"四位一体的育人环境,培养良好的育人机制。     

方以智《东西均·反因》思想发微

明末清初思想家方以智阐言天地间之至理乃相因者皆极相反,现象世界的万事万物皆相待而生,因缘而起,由此以显现象事物之空性,泯除视现象之物为实有的执持.同时,为了破除对道体的执定,进而阐明了反因即正因、用中一贯、不落两边的精微义理,方以智融贯儒释道三教归一的思想大旨由此得以确立.     

Product Family Hierarchical Associated Design and Its Hierarchical Optimization

After reviewing the literature and methodology-related issues within the field of product family design, a deficiency in the current design and development of product family is pointed out. The concept of hierarchical associated design is proposed in this article, according to the deficiency~ and the methods and models for realizing the notion above are described. A two-dimensional analytical model is constructed based on the composing levels and developing processes of product family. The optimization models to hierarchical associated design problems are grouped into two categories： overall-local and key-subordinate. The algorithms of the models are discussed in this paper