非线性系统两变量控制下的分枝特性

采用分枝理论推导非线性系统两变量P和PI控制下的分枝特性,所导得的几个定理阐明了简单分枝点和Hopf分枝点的位置和性质。一个简化精馏塔模型用于演示这一过程,展示出精馏塔系统在闭环时,可能出现多态和极限环。     

矿区铁路专用线下综采放顶煤开采的试验研究

介绍了国内第一个综采放顶煤开采矿区铁路线下压煤试验面的成功经验，总结了试采中对铁路所采取的各种分析和维护措施，分析了该采煤方法下的地在移动和变形特点，为我国“三下”采煤领域提供了具有特色的成功实例。     

Electrochemical studies of glutathione monolayer assembled on a polycrystalline gold electrode

The glutathione (GSH) monolayer and complex monolayer of GSH-metallic ion on polycrystalline gold electrode were studied by using K₃Fe(CN)₆ as the redox probe. As for the GSH monolayer, it was found that the metallic ions could open the ion-gate in the monolayer dramatically in the order La³⁺> Pb²⁺>>Ba²⁺>Ca²⁺ whereas Zn²⁺ ion closed the ion-gate. The complexes of GSH-metallic ions were capable of self-assembling the different kind of monolayer. All the differences were related to the structural configuration of the anchored GSH molecule, which changed with different metallic ions or pH. Biography:Fang Cheng (1971-) male, Ph. D, research direction: electroanlysis.     

The neuronal sortilin-related receptor SORL1 is genetically associated with Alzheimer disease

The recycling of the amyloid precursor protein (APP) from the cell surface via the endocytic pathways plays a key role in the generation of amyloid beta peptide (Abeta) in Alzheimer disease. We report here that inherited variants in the SORL1 neuronal sorting receptor are associated with late-onset Alzheimer disease. These variants, which occur in at least two different clusters of intronic sequences within the SORL1 gene (also known as LR11 or SORLA) may regulate tissue-specific expression of SORL1. We also show that SORL1 directs trafficking of APP into recycling pathways and that when SORL1 is underexpressed, APP is sorted into Abeta-generating compartments. These data suggest that inherited or acquired changes in SORL1 expression or function are mechanistically involved in causing Alzheimer disease.     

海图改正实验的探索

本文介绍了英版航海通告的内容和使用方法,以及如何从网络上下载航海通告及相关查询,阐述了航海通告的处理和海图改正方法.     

水平滑模水泥混凝土无侧限压缩力学特性试验

对不同配比、不同加载速率和不同放置时间下新拌滑模水泥混凝土无侧限压缩下的力学特性进行了试验 ,并从理论上对试验结果作了进一步分析 ,揭示了新拌滑模水泥混凝土的力学特性与材料配比、加载速率、放置时间的变化规律 ,为水平滑模摊铺施工和摊铺机相应工作装置的开发研究提供了试验研究依据。     

关于W变换性质的进一步讨论

根据W变换和Delta函数的定义，讨论了函数f(x)的线性函数af(x) b的W变换和函数Ⅱi-1^n，(x)的W变换问题，并推广了W变换的线性性质，得到了几个进一步的结果．     

“情报门”还是“情报丑闻”?

近日报刊、电视等媒体上常出现"情报门"、"凯利门"等词.前者指伊拉克武器情报事件,后者指武器专家凯利自杀事件.     

基于3S技术的土地利用动态变化研究

3S技术是进行资源环境研究的重要技术手段,在土地利用动态变化研究中,应用3S技术能够快速地获取动态变化信息,并进行空间叠加分析,具有传统方法无可比拟的优越性。该文以北京市密云县为例,探讨了基于3S技术的土地利用动态变化研究方法;并在3S技术支持下,对密云县1991年到2001年的土地利用状况进行了定量的变化分析。结果表明:从1991年到2001年,密云县土地利用变化呈现出下列特点——林地面积持续增加,耕地面积不断减少,密云水库面积明显减少,形势比较严峻。     

短正合列的弱可裂

把短正合列的可裂推广到短正合列的弱可裂，并对弱可裂进行了等价刻画，最后还运用左弱可列证明了平坦模的一个充要条件。