Hiroki Matsubara

Using the simple point charge/extended water model, we performed molecular dynamics simulations of homogeneous vapor-liquid nucleation at various values of temperature T and supersaturation S, from which the nucleation rate J, critical nucleus size n(*), and the cluster formation free energy DeltaG were derived. As well as providing lots of simulation data, the results were compared with theories on homogeneous nucleation, including the classical, semi-phenomenological, and scaled models, but no

With the aid of molecular dynamics simulation, we consider why the diffusivity of liquid becomes slower as the liquid is confined to a narrower space. The diffusion coefficient of octamethylcyclotetrasiloxane liquid confined between two mica surfaces was calculated for a range of surface separations from 64 to 23 Å. The resulting separation dependence of the diffusion coefficient can be explained by considering that the molecular diffusion is an activated process. In particular, we find that the

Thermal conductivity of a material can be comprehended as being composed of microscopic building blocks relevant to the energy transfer due to a specific microscopic process or structure. The building block is called the partial thermal conductivity (PTC). The concept of PTC is essential to evaluate the contributions of various molecular mechanisms to heat conduction and has been providing detailed knowledge of the contribution. The PTC can be evaluated by equilibrium molecular dynamics (EMD) an

In this paper, we discuss the molecular mechanism of the heat conduction in a liquid, based on nonequilibrium molecular dynamics simulations of a systematic series of linear- and branched alkane liquids, as a continuation of our previous study on linear alkane [T. Ohara et al., J. Chem. Phys. 135, 034507 (2011)]. The thermal conductivities for these alkanes in a saturated liquid state at the same reduced temperature (0.7Tc) obtained from the simulations are compared in relation to the structural

Water and ammonia are both associated liquids with high thermal conductivity, but their degrees of molecular association are characterized differently by strong and weak hydrogen bonds, respectively. Here, we employed non-equilibrium molecular dynamics simulation to clarify and compare the molecular mechanisms of high thermal conductivity of water and ammonia. The molecular-scale heat transfer was analyzed in relation to molecular configuration using the atomistic heat path analysis [J. Heat Mas

Surfactants have attracted attention as a means of enhancing thermal transport across solid–liquid interfaces. In the present study, non-equilibrium molecular dynamics simulation was used to study the effect of surfactants on interfacial thermal transport at solid–liquid interfaces, from the viewpoint of vibration-mode matching. The solid atom, surfactant molecule, and solvent molecule were all represented by a single atom. The vibrational characteristics of surfactant molecules were altered by

Enhancement of polymer thermal conductivity using nanographene fillers and clarification of its molecular-scale mechanisms are of great concern in the development of advanced thermal management materials. In the present study, molecular dynamics simulation was employed to theoretically show that the in-plane aspect ratio of a graphene filler can have a significant impact on the effective thermal conductivity of paraffin/graphene composites. Our simulation included multiple graphene fillers aggre

We conducted a molecular dynamics simulation of the binary nucleation in the vapor mixture consisting of water and a small amount of sulfuric acid and investigated the microscopic process in relation to the structure of the hydrate (binary cluster composed of sulfuric acid and water). It was observed that the nucleation rate increased with the concentration of sulfuric acid. It was found that the formation of the hydrate is stable as long as its size is small enough, and the hydrate growth by co

The sugar-binding specificities of C-type lectins isolated from marine invertebrates were investigated by frontal affinity chromatography (FAC) using 100 oligosaccharides. The lectins included BRA-2 and BRA-3, multiple lectins from the hemolymph of the acorn barnacle, Megabalanus rosa, and BRL from the acorn barnacle, Balanus rostatus. The diverse sugar-binding specificities of the C-type lectins were determined by FAC analysis. BRA-2 recognized alpha2-6 sialylation but not alpha2-3 sialylation