FIG.32 (a) Dependence on the gate voltage of the current I through 250 parallel narrow Si inversion layer channels at 1.2 K, showing the electric depopulation of subbands. (b) The effect is seen more clearly in the transconductance dI/dVG. Note the absence of universal conductance fluctuations, which have been averaged out by the large number of channels. Taken from A. C. Warren et al., IEEE Electron Device Lett. EDL-7, 413 (1986).