The reasons for error cut-in grinding of cage spherical outside surface of ball basket constant velocity joint is analyzed, and the solution for the problem is put forward.

分析了球笼式等速万向节保持架外球面切入磨削误差产生的原因，并提出解决和调整方法，从而进一步推导出调整计算式。

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Based on the models and the free-form surface formula, the moving envelope surface of ball-end mill is obtained by means of matrix calculating, the topography is modeled and simulated.

基于自由曲面方程，由矩阵运算得出刃线运动包络面，对球头铣刀加工的表面形貌进行了建模和仿真。

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In the ball analogy, the radius of the ball grows as the universe expands, but all points on the surface of the ball (the universe) recede from each other in an identical fashion.

和球类似，随着球的半径增长(正如宇宙膨胀)，球(宇宙)表面的任意点都以同样方式与其他点远离。

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Puffs of dust were evidence of the ball breaking the surface of the pitch as it landed - and batting last should be awkward.

BBC: Jonathan Agnew column

Then there's the vertical bounce of the ball which is affected by the stiffness of the surface.

BBC: SPORT | Tennis | Rules and Equipment | On the rebound

Then, on a smooth. flour-free surface, roll the ball under the palm of your hand until the dough is smooth and firm -- about 1 minute.

CNN: Pizza Dough