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Free transverse vibrations of single-walled carbon nanocones (SWCNCs) are investigated through beam model and molecular dynamics (MD) simulations. The fundamental frequencies of transverse vibrations of cantilevered SWCNCs with different apex angles, top radii and lengths are obtained from the MD simulations. The Timoshenko beam model provides a better prediction of the frequencies than the Euler–Bernoulli...
A carbon nanospring is formed by coiling a single-walled carbon nanotube (n,m) surrounding a cylinder surface with a uniform pitch length and spring rising angle. Both armchair and zigzag carbon nanosprings are studied. Due to the limitations of hexagonal carbon-atom rings and the bond length of carbon–carbon atoms, a maximum rising angle exists for each type of nanospring (n,m), and zigzag nanosprings...
Flake graphite has been found to transform into spherical graphite in liquid nickel. Graphite spheres with diameters ranging from 300 to 1μm have been extracted by acid erosion of the nickel, and have been characterized using various techniques. The surface of graphite spheres shows disordered atomic stacking and defects. This is in agreement with the Raman spectrum result which shows that the structure...
The structural stability of a coaxial carbon nanotube inside a boron–nitride nanotube (C@BNNT) is investigated by molecular dynamics simulation. The geometric structures of armchair C(5,5)@BN(n,n) and zigzag C(9,0)@BN(m,0) nanotubes (n=8–15; m=15–22) are optimized by the density functional theory method using the DMol3 code. A comparison of the variation in the tube radius and analyses of the bind...
Molecular dynamics combined with continuum mechanics is utilized to predict the compressive mechanical properties of carbon nanotubes encapsulating helical copper nanowire (NW@CNTs). The helical structures of the copper nanowires are obtained using the “simulated annealing” method. The compressive behaviors of this kind of composites are studied. The strain energy curves are shown to predict the interaction...
Fourier transform infrared spectroscopy, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy were applied in this study to demonstrate that multi-walled carbon nanotubes synthesized from ethanol flames (F-MWCNTs) inherently have functional groups on their surfaces. This finding clearly indicates that the covalent functionalization of carbon nanotubes can be achieved...
Molecular dynamics simulation is used to study the transport behavior of water molecules along an open-ended single-walled carbon nanotube (SWCNT) under the driving force of methane molecules. The methane molecules pull the water molecules from the inside of a SWCNT along the axial direction. The transport velocity of water molecules increases with increasing number of methane molecules, but decreases...
A molecular mechanics computation is used here to study the mechanical properties of carbon nanorings (5, 5) formed by bending a single-walled armchair carbon nanotube. The critical tension displacements are reported through the calculation of the strain energy for a carbon nanoring subjected to uniform tension on its two symmetrical sides. The buckling shapes of nanorings with odd numbers of units...
Molecular dynamics (MD) simulation is adopted to study the stability of carbon nanorings, where the force-field function describes the interactions of the carbon atoms. A nanoring is formed by bending a straight nanotube (n, m) and connecting its two ends together. Both armchair and zigzag nanorings are investigated, and the critical diameters for stable nanorings are obtained. It is found that zigzag...
Taking typical armchair (5,5) and (10,10) single-walled carbon nanotubes (SWCNTs) as its study subjects, this study adopts the molecular dynamics method to investigate the vacancy defect reconstruction and elastic properties of these SWCNTs with different defect ratios. The results show that single vacancies and di-vacancies in SWCNTs have different reconstructions. A single vacancy reconstructs into...
The molecular dynamics method is used to investigate the effect of amine grafts on the elastic properties of armchair (5,5) (10,10) and zigzag (9,0) (18,0) single-walled carbon nanotubes (SWCNTs). The results show that Young’s moduli of armchair (5,5) (10,10) and zigzag (9,0) (18,0) SWCNTs with no grafts are 948GPa, 901GPa and 804GPa, 860GPa, respectively. When the SWCNTs are grafted with 2–8-amine...
A hybrid continuum mechanics and molecular mechanics model is developed to predict the compressive buckling strain and load for the inelastic buckling of armchair and zigzag carbon nanotubes. The effectiveness of the hybrid model is demonstrated by comparisons of buckling results from the model, molecular dynamics simulations, and continuum models by other workers. The existence of an optimum diameter...
The fracture of carbon nanotubes (CNTs) is studied in this paper. Molecular mechanics models that incorporate the modified Morse potential and reactive empirical bond-order potential are developed to envisage the fracture behavior of perfect CNTs. The tensile strength, fracture strain, and fracture angle under tension are discussed, and special attention is paid to the effects of tube chirality. Explicit...
The combination of PM3 semi-empirical method for geometry optimization, and ab initio DFT (density functional theory) for energy calculation, is used to study the configurations of hydrogen molecules at 0K within the vacuum of C 60 fullerene and carbon nanocapsules. The obtained structural information including the molecular arrangement and structural state of the clusters of H 2 are...
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