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.
（六）放射性同位素，是指化学元素中具有相同原子序数，但质量不同且能发生放射性衰变的核素。
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fills up, so we can eventually append most new tasks to the slice
此外，姚雄杰身边始终聚集着一批投行精英。有着长城证券、西南证券等背景的人才相继被招致麾下，为盛屯系的资本运作保驾护航。借助这些专业人士的力量，姚雄杰从早年那个“草莽英雄”蜕变为长袖善舞的“资本大玩家”。