Minoru T. Miyahara

We report grand canonical Monte Carlo simulations for a Lennard-Jones (LJ) fluid modeled on methane in slit-shaped pores of several materials and pore widths. Three types of pore wall were considered: graphitic carbon (strongly attractive walls), “methane’’ walls (wall attractions equal to those in the adsorbate phase), and hard walls. For each system the change from a fluidlike to a solidlike adsorbed phase was observed, and the shift in freezing or melting temperature from that of the bulk ads

We modeled condensation phenomena within cylindrical nanopores as a possible replacement for the Kelvin model that underestimates nanometer order pore sizes. The proposed model follows the simple concept of a continuum assumption similar to that for the Kelvin model. The difference was in the introduction of the contribution of the pore-wall potential and the curvature-dependent surface tension in our model. A molecular dynamics (MD) technique developed by the authors for isotherm determination

We developed a new molecular dynamics (MD) scheme, introducing the concept of the potential buffering field through which an adsorbed phase could interact with an imaginary gas phase. This simulation cell allowed us to conduct a MD simulation that allowed a change in the number of molecules to attain equilibrium with given equilibrium pressure, like a grand canonical Monte Carlo simulation. By taking another choice for the setting of the cell, the number of molecules stayed constant but the equi

We demonstrate that CO2 gate adsorption behaviour of elastic layer-structured metal-organic framework-11 (ELM-11: [Cu(BF4)2(4,4'-bipyridine)2]), which is a family of soft porous crystals (SPCs), can be described by a thermodynamic model by free energy analysis with the aid of an adsorption experiment and a molecular simulation. The structures of ELM-11 (closed structure) at 273 K after its evacuation and CO2-encapsulated ELM-11 (open structure) at 195-298 K were determined by the Rietveld analys

The effect of equilibrium vapor-phase pressure onto freezing of a simple fluid in a nanopore is examined. We employ a molecular dynamics (MD) technique in a unit cell with imaginary gas phase, which has the benefit of easy determination of equilibrium vapor pressure. The method is shown to give consistent results with those by the grand canonical Monte Carlo (GCMC) method, and to have better feature of smaller degree of hysteresis between freezing and melting. The MD simulations showed liquid–so

Gold nanoshells with tunable surface plasmon resonances are a promising material for optical and biomedical applications. They are produced through seed-mediated growth, in which gold nanoparticles (AuNPs) are seeded on the core particle surface followed by growth of the gold seeds into a shell. However, synthetic gold nanoshell production is typically a multistep, time-consuming batch-type process, and a simple and scalable process remains a challenge. In the present study, a continuous flow pr

Adsorption process and order formation of electrostatically stabilized colloidal particles with a radius of 50 nm onto a planar surface with countercharge are examined. We perform Brownian dynamics simulations with a new three-dimensional cell model, in which the particle-particle and particle-substrate interactions are modeled based on the DLVO theory. The simulations yield the following results: (1) a larger bulk concentration would be required for larger kappaa to reach order formation to com