thresholdn.门槛；开端；界限；入口threshold of load负载阀值threshold neutron阈能中子threshold schemes门限阈值量threshold howling临界啸声threshold sharing门限共享threshold control阈值控制threshold stimuli[医] 阈刺激物threshold setting阈值调整threshold voltage阈电压,临界电压,门限电压,阈值电压threshold segment阈值分割