The map-based sequence of the rice genome

Rice, one of the world's most important food plants, has important syntenic relationships with the other cereal species and is a model plant for the grasses. Here we present a map-based, finished quality sequence that covers 95% of the 389 Mb genome, including virtually all of the euchromatin and two complete centromeres. A total of 37,544 non-transposable-element-related protein-coding genes were identified, of which 71% had a putative homologue in Arabidopsis. In a reciprocal analysis, 90% of the Arabidopsis proteins had a putative homologue in the predicted rice proteome. Twenty-nine per cent of the 37,544 predicted genes appear in clustered gene families. The number and classes of transposable elements found in the rice genome are consistent with the expansion of syntenic regions in the maize and sorghum genomes. We find evidence for widespread and recurrent gene transfer from the organelles to the nuclear chromosomes. The map-based sequence has proven useful for the identification of genes underlying agronomic traits. The additional single-nucleotide polymorphisms and simple sequence repeats identified in our study should accelerate improvements in rice production.     

管式固定床反应器中振荡操作研究

在单管固定床反应器中,研究了V_2O_5颗粒催化剂上邻二甲苯催化氧化反应过程振荡操作的特性。在反应器熔盐温度为362—366℃,空速为2000—3500h~(-1)范围内,以浓度、空速的方波形式,进行了周期操作特性的研究。结果表明,反应过程收率与振荡周期有关,在周期为40—100s时的振荡操作与同样条件的定态操作相比,可以提高反应过程收率3%,并能改善反应器操作特性。     

基于UDDI服务订阅的Web服务推荐机制

针对基于Web服务的分布式系统提出的一种“推”模式的信息传播机制 ,并由此提出了一种利用UDDI服务订阅功能实现Web服务推荐的方案 .文章通过对 3种具体应用场景的分析 ,讨论了该服务推荐机制的可行性及实用性     

答“问难‘族群’”——兼谈“马克思主义族群理论”说

最近读到《问难“族群”》一文 ,其中多处针对笔者的几篇文章提出了评议和“指正”,应该算是对笔者几篇文章的一个回应 ,这是令人高兴的。然而 ,仔细读后 ,又颇为失望 ,“问难”一文所质疑的着眼点并未涉及笔者文章的实质内容 ,除了一些“大而化之”的评论外 ,但凡触及具体问题不是对笔者原文的“误读”(或“未读”)就是“误批”。惟一令人感到需要回应的问题 ,是“问难”作者针对笔者文章中质疑“马克思主义族群理论”说而提出的新论断。为此 ,笔者决定就“问难”一文进行回应     

“朱颜”不等于“美女”——李煜词《虞美人》的一处误注

李煜《虞美人》是脍炙人口的文学作品,其中“雕栏玉砌应犹在,只是朱颜改”中“朱颜”一向被众多选家注为“美人”,本文作者根据考证认为“朱颜”应理解为词人自伤之词,指后主昔日红润的容颜变得憔悴,用以泛指人事的巨大变迁。     

EFFECT OF OPENING OPERATING PARAMETERS ON YARN QUALITY IN FINE AND MEDIUM COUNT FRICTION SPINNING

In this paper, a quantitative analysis of the opening quality in friction spinning and its main ef-fecting factors is first made. Upon this basis the Box-Hunter's experimental design method is usedto establish the quadratic regressional equations in terms of primary opening technologicalparameters and yarn quality for medium and fine count friction spinning. The results of analysisand discussion show that the proper choice of opening roller speed and its reasonable match withthe yarn count is singificant for ensuring the spinning quality index as well as reducing unevenness,thin and thick places of the yarn.     

机器人双臂操作中防碰的一个实用数学模型及计算

本文以实用为目的,给出了用计算机预测双臂机器人操作过程中互相碰撞的时间的可行算法,以达到避免碰撞的目的,使用LISP语言在VAX—8350机上实现了本文设计算法的仿真过程,完全达到了预期的效果。     

方解石的辐照效应和ESR测年法的研究

本文研究了人工合成方解石和天然石笋样品的ESR谱及在α、β、γ射线辐照下的效应。由实验测出的TD和D值,计算出周口店第四地点石笋平均年龄为(6.0±0.8)×10~4年,此值与轴系法测得的平均年龄(6.5±0.4)×10~4年一致。     

2101船用Al-Mg合金的显微组织

2101 Al-Mg合金是我国根据船舶工业需要创制的一种新型合金,该合金具有中等强度,良好的耐蚀性和优良的焊接性。各种性能试验和电子显微镜观察表明,综合性能的改善与变形度和稳定化处理工艺密切相关,这种关系是通过控制位错结构来实现的。本研究采用大于30%变形度和240～270℃/0.5～4h低温稳定化处理控制位错分布状态,从而使β相在晶内外均匀析出,并借助位错管道模型阐明β相的析出过程。