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Understanding the interaction between hydrogen and carbon nanotubes is crucial to enhancing the performance of hydrogen storage and nanofluidic carbon-adsorbent systems. Accordingly, this study performs a series of molecular dynamics simulations to investigate the transport properties of hydrogen molecules confined within a flexible narrow carbon nanotube. The tube's diameter is 10.8Å at temperatures in the range of 100∼800 K. The particle loadings inside carbon nanotubes are ranging from 0.01∼1 No/Å. The results show that the hydrogen molecules exhibit three distinct diffusion regimes, namely, single-file, Fickian, and ballistic, depending on the value of the Knudsen number. In addition, it is shown that with the Knudsen number of less than 1, the tube-wall long wavelength acoustic phonons induced Rayleigh traveling wave prompts a longitudinal wave slip and compression-expansion of the hydrogen molecule crowds within the CNT, which leads to a significant increase in the mean square displacement of the molecules.

This study performs molecular dynamics simulations in order to clarify the atomic-scale stick–slip behaviour commonly observed when performing surface measurements using an atomic force microscope (AFM). In investigating the surface effects of adhesion, contact deformation, nanoindentation and fracture which occur when a diamond tip interacts with a copper surface, this study considers that both the substrate and the tip deform. The theoretically predicted dynamic behaviour of the AFM cantilever tip includes tip oscillation and noise induced by adhesion, nanoindentation and fracture effects. Molecular dynamics simulations are performed to clarify the atomic-scale friction mechanisms associated with surface deformation and to investigate the dynamic behaviour of the tip during AFM surface measurement. The relative influences of the adhesion, nanoindentation and fracture effects upon the stick–slip phenomenon are investigated.