30.若操作頻率5 MHz,Doppler角度45度,Doppler偏移4.6 kHz,則其流速為多少(cm/s)?
(A)50
(B)100
(C)120
(D)150
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統計: A(79), B(731), C(135), D(85), E(0) #3282990
統計: A(79), B(731), C(135), D(85), E(0) #3282990