题目内容

由动量矩方程可知,没有水流对转轮动量矩的改变,转轮就不可能获得水流能量而做功。()

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机组台数越大,单机容量越小,安装运输方便,耗费材料少,造价低。因此一般选用较小容量的机组,增加机组台数。()

由转轮翼型引起的气蚀,通常发生在叶片出水边的背面。()

水轮机基础环位于座环下环与蜗壳之间,主要用于传递力矩。()

Section A
How to Grow Old
By Bertrand Russell
Some old people ale oppressed by the fear of death. In the young there is a justification for this feeling. (81) Young men who have reason to fear that they will be killed in battle may justifiably feel bitter in the thought that they have been cheated of the best things that life has to offer. (82) But in an old man who has known human joys and sorrows, and has achieved whatever work it was in him to do, the fear of death is somewhat abject and ignoble. (83) The best way to overcome it— so at least it seems to me—is to make your interests gradually wider and more impersonal, until bit by bit the walls of ego recede, and your life becomes increasingly merged in the universal life. An individual human existence should be like a river—small at first, narrowly contained within its banks, and rushing passionately past boulders and over waterfalls. Gradually the fiver grows wider, the banks recede, the waters flow more quietly, and in the end, without any visible break, they become merged in the sea, and painlessly lose their individual being. (84) The man who, in old age, can see his life in this way, will not suffer from the fear of death, since the things he cares for will continue. And if, with the decay of vitality, weariness increases, the thought of rest will not be unwelcome. (85) I should wish to die while still at work, knowing that others will carry on what I can no longer do and content in the thought that what was possible has been done.
(51)

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