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本文建立了四边挠度为零的矩形扁壳弹性弯曲问题的一般解析解.以四边位移为零的固支矩形扁壳为例求解了对称变形问题。 相似文献
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黄炎 《应用数学和力学(英文版)》1987,(8)
In this paper a general solution of rectangular plates in bending is given.The integralconstants are determined by means of boundary conditions.This method is simpler andeasier than the method of superposition. 相似文献
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Based on the nonlinear geometric relation between strain and displacement for flexible cable, the equilibrium equation under self-weight and influence of temperature was established and an analytical solution of displacement and tension distribution defined in Eulerian coordinate system was accurately obtained. The nonlinear algebraic equations caused by cable structure were solved directly using the modified Powell hybrid algorithm with high precision routine DNEQNE of Fortran. For example, a cable structure consisting of three cables jointly supported by a vertical spring and all the other ends fixed was calculated and compared with various methods by other scholars. 相似文献
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本文采用甲基丙烯酸2-羟乙酯(HEMA)与乙二醇二甲基丙烯酸酯在移液器枪头中共聚制备固相微萃取整体柱,用于直接处理尿液中3种苯二氮卓类药物(BZDs)。实验考察了单体用量、聚合时间及固相微萃取条件对BZDs萃取效率的影响,评价了其吸附性能。当HEMA用量为40 mg,聚合温度60℃时,固相微萃取整体柱对目标物吸附效率达98.9%~100%,且对尿液中杂质的吸附率低于10%。取3 mL尿液样品,无需处理,直接上样至该柱,经4 mL纯净水冲洗,1 mL乙腈洗脱,得到的样品结合高效液相色谱仪分析。方法对3种BZDs在2.5~1 000 ng/mL浓度范围呈现良好线性关系(r=0.999),检出限(S/N=3)和定量限(S/N=10)为0.8~1.5 ng/mL和2.5~5.0 ng/mL,回收率为86.2%~107%。本方法构筑的萃取柱制备简单,能实现对原始尿液的直接、高效萃取,操作便捷。 相似文献