By assuming the weak lens focal length expression to be the first term in a power series a simple and accurate formula can be derived for the objective focal length of a magnetic electron lens.

用假设弱透镜焦距表达式是一个幂级数中的第一项的方法，可以导出相当准确且便于实用的电磁电子透镜物镜焦距公式。

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Once unleashed, the power channels through a positively charged continuous energy lens at the center of the handle.

一旦被释放，能量会通过剑柄中部带正电荷的能量透镜。

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It will be used in the illumination system of high power semiconductor laser over a long infrared distance of 100 meters through adjusting an additional geometric optical lens.

然后通过调节外加的几何光学透镜，在长达100米的红外远距离大功率半导体激光器照明系统中将得到利用。

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The power of a large and heavy size super-telephoto lens is available on the compact body of the SP-720UZ, fitting in the palm of your hand, and making it the perfect companion for keeping baggage light on a trip.

ENGADGET: Olympus introduces Stylus SP-820UZ, SP-720UZ cameras and SZ-14 binocular bundle

The compact body of this camera is crammed with the power of a high-performance SLR 600 mm telephoto lens.

ENGADGET: Olympus introduces Stylus SP-820UZ, SP-720UZ cameras and SZ-14 binocular bundle

The power of the lens can be altered progressively by flooding these compartments one at a time.

ECONOMIST: Cataracts