A rare galaxy type, polar ring galaxies have a substantial population of stars, gas, and dust orbiting in rings nearly perpendicular to the plane of the galactic disk.

极环星系是种稀有的星系类型，它们有着几乎和银盘平面垂直，呈环形公转的大量的恒星、气体和星尘。

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The optimum design of plane quadratic enveloping ring surface worm drive has been realized using the theory and method of optimization.

针对平面二次包络环面蜗杆传动，运用优化理论和方法，对其进行了优化设计。

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Presented the routing method of the packet going to the RPR ring network and its control plane and forwarding plane design.

研究提出了报文上RPR环网的选路表方法，以及控制平面和转发平面的设计实现。

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Other activities for Cassini scientists during the extended mission will include monitoring seasons on Titan and Saturn, observing unique ring events - such as the 2009 equinox when the Sun will be in the plane of the rings - and exploring new places within Saturn's magnetic "envelope" - or magnetosphere.

BBC: Nasa extends Saturn probe mission