It is also shown that only when the gratings are cylinder or plane ones, the second order sagittal anastigmatic circular field and meridional non defocus flat field spectral images can be formed.

还指出仅当柱面或平面光栅时，才能形成二阶子午无离焦平场和弧矢无象散圆场谱面。

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In a dusty field in Kitui, eastern Kenya, farmers are being taught how to construct small, semi-circular barriers of earth that control the flow of water, slowing its run-off.

在肯尼亚东部的基图伊，尘土弥漫的田地里，农民们正学着建造小型的环形土坝，以此控制水量、减缓水分流失。

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And finally, the department table has a ADMRDEPT field which is a circular link to itself (identifying departments that manage other departments).

最后，department表有一个ADMRDEPT字段，该字段是到其自身的一个循环链接(标识管理其他部门的部门)。

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Many of the semi-finalists' redesigns are as simple as adding multitouch gestures or bending the traditionally square playing field into a more circular court, but a few ambitious developers mixed it up with 3D playing fields, anthropomorphic paddles or augmented reality multiplayer.

ENGADGET: 15 indie developers re-imagine Pong for iOS, hope to win Atari contract

"We've had our field services team out on the 5km of right of way, the circular route, clearing trees to get it all open, " he said.

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