@entity2459 in a thermally driven rotary motor made from double-walled XXXX nanotubes.

@entity505 @entity2459 @entity28309
UNASSIGNED: In a thermally driven rotary motor made from double-walled @entity505 nanotubes, the @entity28309 (inner tube) can be actuated to rotate within the stator (outer tube) when the environmental temperature is high enough. A sudden stoppage of the @entity28309 can occur when the inner tube has been actuated to rotate at a stable high speed. To find the mechanisms of such sudden stoppages, eight motor models with the same @entity28309 but different stators are built and simulated in the canonical NVT ensembles. Numerical results demonstrate that the sudden stoppage of the @entity28309 occurs when the difference between radii is near 0.34 nm at a high environmental temperature. A smaller difference between radii does not imply easier activation of the @entity2459 . During rotation, the positions and electron density distribution of atoms at the ends of the motor show that a sp(1) bonded atom on the @entity28309 is attracted by the sp(1) atom with the biggest deviation of radial position on the stator, after which they become two sp(2) atoms. The strong bond interaction between the two atoms leads to the loss of rotational speed of the @entity28309 within 1 ps. Hence, the sudden stoppage is attributed to two factors: the deviation of radial position of atoms at the stator's ends and the drastic thermal vibration of atoms on the @entity28309 in rotation. For a stable motor, sudden stoppage could be avoided by reducing deviation of the radial position of atoms at the stator's ends. A nanobrake can be, thus, achieved by adjusting a sp(1) atom at the ends of stator to stop the rotation of @entity28309 quickly.
