空回 空回是指不至引起反向可测量输出的最大输入量，轴向预紧不够或者传动链元件的啮合不好导致空回。 空回会影响传动精度和系统稳定性。
导出摆动活齿传动空回行程不自锁条件，并给出克服自锁的方案。
Self-locking conditions of return stroke of swing movable teeth are deduced and methods to overcome self-locking are obtained.
此外，确定你希望改变的让你不舒服或痛苦的东西是一回事，而坐下来空抱怨却是另一回事。
It is one thing to identify something uncomfortable or painful you wish to change, and another to sit and complain about it and do nothing.
如果服务器端组件上的方法具有非空返回值，该值就会作为其惟一的实参传递进此回调函数。
If the method on the server-side component has a non-void return value, that value is passed into the callback function as its only argument.
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