共查询到19条相似文献,搜索用时 156 毫秒
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Meso紧空间、Hausdorff空间的映射性质 总被引:2,自引:0,他引:2
完备映射是拓扑映射中一种简单而重要的映射.通过研究完备映射的性质以及Hausdorff 空间、Meso紧空间的结构,证明了完备映射下Hausdorff 空间的性质及 Meso紧空间被完备映射逆象保持,从而完善了这几种拓扑空间的性质刻画. 相似文献
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Hermite-Hadamard不等式是经典的不等式之一,应用比较广泛。关于Hermite-Hadamard不等式的推广、改进和加细等已有很多成果,大多数都是通过两边作差,研究其单调性。而本文用不等式的性质对其进行研究,在有理数域上给出了Hermite-Hadamard不等式的无限加细(定理1.1);进而推广到实数域,得出Her-mite-Hadamard不等式的另一种加细(定理1.2)。 相似文献
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也许是因为它太著名的缘故,人们对外森伯克不等式已经作了好几种形式的加强[1],本文将给出另一种加细形式. 约定 R、r、D分别指△ABC的外接圆半径、内切圆半径、面积、s指△ABC的半周长. 引理1 △ABC中,有 D4coscoscos222ABCRr=. 证明 D22sinsinsinRABC=, r =4sinsinsin222ABCR, 两式相除得 4coscoscos222ABCRrD=, 即 D4coscoscos222ABCRr=.证毕. 引理2 △ABC中,23/9Rr矰. 注意到33coscoscos2228ABC,易得. 引理3 △ABC中,22218abcRr++? 证明 要证原不等式成立,只要证 222184abcabcsD++匙譊. 即证 22292abcab… 相似文献
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通过对拓扑补空间的定义形式进行延拓,得到一些新形式的拓扑补空间,从而进一步完善拓扑补空间的构建。 相似文献
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曾红卫 《上海大学学报(英文版)》2010,14(1):1-5
This paper adopts counterexample guided abstraction refinement scheme to alleviate the state explosion problem of deadlock detection. We extend the classical labeled transition system models by qualifying transitions as certain and uncertain to make deadlock-freedom conservative, i.e. if the abstraction of a system is deadlock-free, then the system is deadlock-free. An abstraction refinement approach to deadlock detection is proposed, and the correctness of the approach is proved. 相似文献
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宣兆成 《天津工程师范学院学报》2005,15(4):1-7,13
给出了偏微分方程的h型有限元分析的双层网格最优精化设计方法。第一层是细化后验误差相对大的单元?后验误差是通过简化计算由单元平均流量为连接的单元Neumann型子问题而得到的误差界。简化计算就是只把由1/2单元尺寸所构成的网格上的泛函作为单元残余误差方程的试探函数,这样计算成本将非常小。某些精化后的网格的几何性质将变得很差,所以第二层又用Laplace光顺算法对网格的质量进行改进,并用两个例题验证了该方法。结果表明,算法达到最优收敛率,并提高了精度。 相似文献
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模糊数学理论在星级公体教师评价中的应用 总被引:1,自引:0,他引:1
龚江泳 《宁波职业技术学院学报》2009,13(2)
对高校公体教师的综合素质制定比较全面、合理、科学的评价方法,应用模糊综合评价理论建立数学模型来科学评价公体教师综合素质,赋予相应星级,从而调动广大教师的积极性和创造性,推动学校体育工作的进步和发展. 相似文献
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针对政府采购最常用的综合评分法评审细则制定中容易出现的问题,详细探讨了评审细则的细化设置方法以及评审执行中应当注意的工作程序和操作规范。 相似文献
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In order to obtain the optimized structure rubber, a novel miktoarm star styrene-butadiene rubber (MS-SBR) was initiated by a multifunctional macromolecular initiator with polydiene arm and Sn-C bond. The properties of MS-SBR were investigated with respect to the morphology, mechanical properties, and dynamic viscoelasticity in comparison with those of the blends, natural rubber (NR)/star styrene-butadiene random rubber(S-SBR) blend rubber and cis-1,4-polybutadiene rubber (cis-BR)/S-SBR blend rubber. The samples were analyzed using transmission electron microscopy (TEM), dynamic mechanical thermal analyzer (DMTA), and mechanical properties test. The analysis results show that MS-SBR possesses the desired combination of low rolling resistance and high antiskid resistance, and is promising for application in high performance tire tread. 相似文献
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介绍了中子星研究简史、中子星结构模型和中子星结构方程,阐述了目前中子星研究的几个层次及所采用的理论工具.对中子星研究的未来作了展望. 相似文献
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Microstructure Refinement of Sn-Sb Peritectic Alloy under High-Intensity Ultrasound Treatment 总被引:2,自引:0,他引:2
In this paper the solidification behavior of Sn-Sb peritectic alloy and the mechanism of grain refinement in solidification process under high-intensity ultrasonic field are investigated. Three different powers of high-intensity ultrasound are introduced into molten Sn-Sb peritectic alloy to study the refining effectiveness. The results show that the application of high-intensity ultrasound during solidification process of Sn-Sb peritectic alloy can refine a phase and β phase and eliminate gravity segregation of the alloy. As acoustic intensity is increased from 400 W to 800 W, not only the homogenous fine structure can be obtained, but also the cubic β phase crystals tend to be spherical. Microstructure of the sample treated by 600 W high-intensity ultrasound demonstrates the best refining effect. 相似文献