“…(23) is a good approximation with relatively high accuracy, but this model is a solution to the phonon Boltzmann equation with Gray model (single mean free path), and the localized atomic vibrations and hopping are not considered. Therefore, more accurate solutions to the backbone thermal conductivity can be obtained by the nanoscale numerical methods, such as the Molecular Dynamics simulation [126e128], Monte Carlo method [129e133] and solving the phonon Boltzmann equation[133,134]. In addition, such numerical solutions can also be employed to improve the prediction accuracy of the numerical model described in Section 3.2.4, i.e., act as the thermal conductivity of solid phase in Eq (62)…”