Molecular dynamics simulation of single-walled silicon carbide nanotubes immersed in water.

The structure and dynamics of water confined in single-walled silicon carbon nanotubes (SWSiCNTs) are investigated using molecular dynamics (MD) simulations. The density of water inside SWSiCNTs is reported, and an equation is suggested to predict the density of water inside SWSiCNTs. Interestingly, the water diffusion coefficients (D) here are larger compared with those in SWCNTs and single-walled boron-nitride nanotubes (SWBNNTs).

Phase transition study of confined water molecules inside carbon nanotubes: hierarchical multiscale method from molecular dynamics simulation to ab initio calculation.

In this study, the mechanism of the temperature-dependent phase transition of confined water inside a (9,9) single-walled carbon nanotube (SWCNT) was studied using the hierarchical multi-scale modeling techniques of molecular dynamics (MD) and density functional theory (DFT). The MD calculations verify the formation of hexagonal ice nanotubes at the phase transition temperature T(c)=275K by a sharp change in the location of the oxygen atoms inside the SWCNT. Natural bond orbital (NBO) analysis provides evidence of considerable intermolecular charge transfer during the phase transition and verifies that the ice nanotube contains two different forms of hydrogen bonding due to confinement.

Application of ab initio theory to QSAR study of 1,4-dihydropyridine-based calcium channel blockers using GA-MLR and PC-GA-ANN procedures.

The usefulness of the quantum chemical descriptors, calculated at the level of the RHF theory using 6-31G basis set for QSAR study of 1,4-dihydropyridine-based calcium channel antagonist was examined. A data set containing 45 dihydropyridine derivatives with known activity was used. Multiple linear regressions combined with genetic algorithm for variable selection and an artificial neural network model combined with principal component analysis for dimension reduction and genetic algorithm for factor selection (PC-GA-ANN) were employed.