排序方式: 共有57条查询结果,搜索用时 15 毫秒
51.
52.
利用自制简易实验探究了水产生的浮力能否大于其所受重力大小的问题,强调了浮力计算公式中V排为物体排开液体的体积,而非排出液体的体积,进一步验证了阿基米德原理的正确性.同时,利用电子天平较为精确地展示出了浮力的反作用力的大小. 相似文献
53.
54.
55.
以丹麦为大本营的Hanss Acoustics,推出的2款模拟唱机分别为T20和T30.两机基本采用相同的构造,主机底盘利用磁性相斥的悬浮原理,通过3根支柱形成了极其稳健的支撑点,相当合理的设计,应对了在重量级转盘中常见的负荷问题.主轴内还装有支轴,支轴的下方与主轴的上方分别安装有磁铁,通过磁铁的反作用力来实现减压. 相似文献
56.
伸缩式皮带机是邮件运输过程中很有用的设备,但由于存在伸缩梁震动的问题,影响了它的使用、因此本文根据力学的原理,分析了该皮带机各种受力的情况及伸缩梁震动的原因,提出了一些解决的办法,以与读者探讨。 相似文献
57.
莫嘉琪 《应用数学和力学(英文版)》2008,29(8):1105-1110
In this paper, a class of nonlinear singularly perturbed initial boundary value problems for reaction diffusion equations with boundary perturbation are considered under suitable conditions. Firstly, by dint of the regular perturbation method, the outer solution of the original problem is obtained. Secondly, by using the stretched variable and the expansion theory of power series the initial layer of the solution is constructed. And then, by using the theory of differential inequalities, the asymptotic behavior of the solution for the initial boundary value problems is studied. Finally, using some relational inequalities the existence and uniqueness of solution for the original problem and the uniformly valid asymptotic estimation are discussed. 相似文献