Optical-based smoke alarms use light instead. They are slightly better at detecting the large smoke particles created by slow, smouldering fires. When such particles enter a chamber in the device, they scatter light from a small light source, which is then picked up by a photoelectric sensor.
The crew of Apollo 8 would be the first to travel beyond low Earth orbit and enter the gravitational pull of another celestial body.
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Германия — Бундеслига|24-й тур
这套说辞在法律上也许站得住脚，但它同时也揭示了一件事：这家公司从未认为自己做错了什么，只是某些手段不够干净。