An aligned double-walled carbon nanotube bulk structure composed of plural aligned double-walled carbon nanotubes and having a height of 0. Specular and scattered light returned from the surface onto the parabolic mirror is divided into appropriate fields and directed onto detectors. Active users in the set of human users authoring a number of textual messages regarding the particular topic more than a threshold number of textual messages are selected. Thus, an increase of both bandwidth and voltage gain is achieved. The AC signal, which drives an AC load, is applied to the anti-series devices.