The linings of the brake shoes are moved hydraulically against the brake drum to stop its rotation. 加衬里的制动闸被移动对着鼓状闸来使其停止转动。
Plants that lack this brake end up with a hair-trigger response to infection,which helps them to snuff out a smouldering infection before it catches. 缺少这种制动闸的植物最后对感染会有一触即发的反应，这有助于它们在发病前消灭潜伏的感染。
