Over-Speeding Rotational Transmission of a Carbon Nanotube-Based Bearing

In studying the rotational transmission behavior of a carbon nanotube-based bearing (e.g., (5, 5)/(10, 10)) driven by a CNT motor (e.g., (9, 9)) at finite temperature, one can find that the rotor has different dynamic states from the motor at different environmental condition. In particular, the rotor can be in the overspeeding rotational transmission (ORT) state, in which the rotational speed of the rotor is higher than that of the motor. If we change the rotational frequency of the motor (e.g., >100 GHz) and the curved angle of the rotor, the bearing can reach the ORT state. Besides, in the ORT state, the ratio of the rotor’s rotational speed over that of the motor will be not higher than the ratio of the motor’s radius over that of the rotor. There are two major reasons that result in the bearing to the ORT state. One is that the thermal vibration of atoms between the carbon–hydrogen (C–H) end of the motor and that of the rotor has a drastic collision when the motor is in a high rotational speed. The c...