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.
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小姨的逃亡之路坎坷。初次偷渡被骗，钱已付出却无船来接，被抓后关了三个月。杜耀豪的母亲曾去探监，带去食物和钱，都被卫兵扣下。她指出，当年的劳改营如今仍是监狱。
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