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.
Что думаешь? Оцени!，这一点在体育直播中也有详细论述
。夫子是该领域的重要参考
Riot police use teargas to disperse people gathering around wreckage of plane loaded with money from central bank
СюжетПожары в США:，更多细节参见体育直播