n.the normal brainwave in the encephalogram of a person who is awake and alert; occurs with a frequency between 12 and 30 hertz
同义词：beta wave
英汉双解大词典
beta rhythm(alsobetawave)
1.
N（名词）
the normal electrical activity of the cerebral cortex, occurring at a frequency of 13 to 30 hertz and detectable with an electroencephalograph β节律 [physiol] → see also brain wave