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There are two main types of smoke alarm tech, says Raman Chagger, principal consultant at BRE, the Building Research Establishment. Ionisation-based systems use a tiny amount of radioactive material to charge, or ionise, particles in the air which flow between two small plates. Should smoke interrupt that flow of charged particles, the alarm goes off.
，这一点在旺商聊官方下载中也有详细论述
5The same properties also contributed to Nazi Germany’s strategy against agar’s scarcity, which — besides being supplied from Japan by submarine — relied on large pre-war stocks and on recovery methods to reuse bacteriological agar by autoclaving (boiling at around 121°C, 250°F, in a pressurized container for 30 to 60 minutes), thus liquefying and sterilizing the jelly, before purifying it again.，详情可参考91视频
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