由于地球的球面形状，在至日突出的表面阻挡了阳光照射照远端的半球；同样是球面的原因，在至日阳光可以照射两极的更多地方。
The bulge of our spherical Earth blocks sunlight from the far hemisphere at the solstices; that same curvature allows the sun's rays to spread over more area near the top and bottom of the globe.
目的研究凹球面超声换能器的声焦域在高声强和媒质有较大衰减情况下，其形状和几何位置的变化。
Objective the variations of the site and shape of focal region for a concave spherical ultrasound transducer in the case of high sound intensity and stronger attenuation were studied.
本文讨论球面范成法成形的一般原理，分析和计算范成表面的形状偏差，给出若干数据和结果。
The general principle of the precise spherical generation is discussed. The deviation of the resulting surface shape is analysed and calculated. Some data and results are given.
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