The internal ground resistor limits the reverse battery ground current.

内部接地电阻限制了电池反向接地电流。

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The laser, aimed from the ground at photovoltaic cells mounted on the Pelican's underside, charged the chopper's battery, keeping her aloft for an unprecedented 12 hours and 27 minutes.

激光器从地面上瞄准位于“鹈鹕”下侧的太阳能电池为这架直升机充电，使它开历史之先河，在空中足足盘旋了12小时27分。

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Think of the ionosphere and the ground as the terminals on the battery and you put a wire between those two terminals and current flows, and literally you get a spark.

把电离层和地面想象成电池的两极。 用一根导线连接这两极的话，电流就会流动，然后就会产生火花。

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It remains to be seen how that Motorola performs in real life, but it seems certain Apple has not staked out new ground on battery life here.

FORBES: iPhone Haters are "Right," Nothing to See Here

Meanwhile, the time it is likely to take to thoroughly investigate and fix the battery problem alone ought to ground the 787 for months.

FORBES: Why 787 Dreamliner Battery Woes Are the Tip of Boeing's Iceberg

It also uses a tether and can stay aloft for 12-hours on a single ground-station battery, letting it spy from afar with on-board HD, night-vision and thermal cameras.

ENGADGET: CyPhy Works reveals tethered flying bots that can spy on you indefinitely (video)