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.
本报北京2月26日电 （记者彭波）全国人大常委会委员长赵乐际26日下午主持十四届全国人大常委会第二十一次会议闭幕会。在会议完成有关表决事项后，赵乐际作了讲话。
，这一点在体育直播中也有详细论述
Согласно данным иранского агентства Tasnim, в Тегеране прогремело как минимум два взрыва, очевидцы сообщают о густом дыме в небе.
据新浪科技消息，阶跃星辰据悉计划在港股 IPO。