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INTRODUCTION Since the phenomenon of piezoelectricity in natural crystals was discovered in 1880, it has been applied in many fields, such as smart structure, sensing devices and active control, because of its special properties. Combining electrical behavior with mechanical deformation is the special property which attracted great interest of researchers. Many models have been developed for studying piezoelec- tric effects. Dunn and Wienecke (1996) used Green’s functions for transverse… 相似文献
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伴随教育体制的变革、办学自主权的扩大,教学管理中出现的问题也越来越多,基于问题解决的“问题管理”也就应运而生。近年来,湖南省吉首市第二小学从问题人手,以问题为中心对学校实施管理,我们称它为“问题管理”,收到了良好的效果。问题管理的基本流程是:问题征集、问题整理、问题征解、问题论证、问题管理、问题管理评价。 相似文献
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问题1(数学通报2020年第12期问题2576)2已知x>0,y>0,y3(5-2x3)=3,求P=2/x2+3y2的最小值.解法1:由3元均值不等式可得x2=1·x·x≤1/3(13+x3+x3),即x2≤1/3(1+2x3). 相似文献
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马晨明 《上海大学学报(英文版)》2008,12(5):377-382
Hamiltonian system for the problem on clamped Mindlin plate bending was established by introducing the dual variables for the generalized displacements in this letter. By separation of variables, the transverse eigen-problem was derived based on the sympletic geometry method. With the solved sympletic eigen-values, the generalized sympletic eigen-solution was derived through eigenfunction expansion. An example of plate with all edges clamped was given. The sympletic solution system was worked out directly from the Hamiltonian system. It breaks the limitation of traditional analytic methods which need to select basis functions in advance. The results indicate that the sympletic solution method could find its more extensive applications. 相似文献
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《中学数学教学》2010年第1期有一道问题征解:已知x、y、z〉0且x+y+z=1,求证:1/2≤ln(x^3+y^3+z^3)/ln(x^5+y^5+z^5)〈3/5. 相似文献
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一道美国数学月刊问题的简解 总被引:3,自引:3,他引:0
设x,y,z∈(0,+∞)且x2+y2+z2=1.求函数f=x+y+z-xyz的值域. 此问题最早出现在美国<数学月刊>问题征解中,后又出现在中国不等式研究小组网站上寻求初等的解法,至今无人给出它的初等解法.笔者通过三角及导数的知识给出了此问题的一种简解,现整理出来供参考. 相似文献
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有关不等式的证明题在各类考试,特别是在各级数学竞赛中经常出现,也是很多数学杂志问题征解的一个热点.不等式的证明方法灵活多变,技巧性很强.学习不等式的证明,不仅对提高学生的解题能力有着重要作用,而且对培养学生思维的灵活性和创造性具有较高的价值,构造法在证明不等式中有着突出的作用. 相似文献