Molecular level understanding of the contact line is important for phase change heat transfer such as evaporation and condensation. We have performed molecular dynamics studies of liquid droplet on the solid surface. In the case of Lennard-Jones droplet, the strength of interaction between solid and liquid directly affect on the contact angle. In the simulation of the water droplet on the platinum surface, a stable droplet structure on a monolayer film was obtained. And the apparent contact angle of the droplet was varied drastically according to the density and the structure of this monolayer. The structure of water droplet on graphite surface resembled that of Lennard-Jones droplet, but layered structure near the solid surface was decreased. The difference between advancing contact angle and receding contact angle was not observed.

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Effects of nano-scale roughness upon a moving droplet on a solid surface are investigated through molecular dynamics simulation. Droplet of argon liquid with 12-6 Lennard-Jones potential is driven by gravitational force applied to a direction parallel to the solid surface. Difference of contact angle between the droplet with and without the gravity is discussed. Droplet behavior in traveling on the solid with a single and double lines of solid molecule perpendicular to the direction of the gravity is examined.

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In thermocapillary convection of a half-zone liquid bridge, a phenomenon called "Spiral Loop-PAS (SL-PAS)" is observed, in which particles gather along a three-dimensional closed single loop. In this paper, the three dimensional numerical simulation of the thermocapillary convection in a half zone liquid bridge is performed to reconstruct the SL-PAS through the finite difference method with employing the Eulerian method for fluid flow and the Lagrangian method for particle motion. In particular, a series of numerical simulation has been conducted for n-Decane (Pr=15 at 25 deg C) with the heat loss to the ambient air being taken into account. An influence of the heat loss to the ambient air on emergence of the SL-PAS is examined. The SL-PAS has been successfully reconstructed in consideration of the heat loss to the ambient air.

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Oscillation and rotation of an electro-statically levitated liquid droplet are studied experimentally and numerically. It is shown that the oscillation frequency decreases as the oscillation amplitude increases while it increases as the rotation number increases.

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We develop a Stochastic Rotation Dynamics (SRD) model of amphiphilic molecules to study its spontaneous aggregation into micelles, vesicles and lamellar. In our talk, 1) we introduce a color method to take into account molecular interactions in SRD scale; 2) we discuss how we should determine parameters of SRD; 3) we show a simulation result of self-assembling forms of amphiphilic molecules. Concluding remarks are given in the last.

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To understand interactions between protein molecules and inorganic substrates, we succeeded in observing individual fluorescence labeled lysozyme (F-lysozyme) molecules diffusing in the vicinity of the surfaces of SiO_2 and glass substrates, in real time, by a single molecule visualization technique. Our results indicated that diffusion coefficients of F-lysozyme molecules on SiO_2 and glass substrates are 3-4 orders of magnitude smaller than those in solution. In addition, number of F-lysozyme molecules observed per μm^2 for one second on a SiO_2 substrate is about 20 times smaller than that on a glass substrate. These results show that the activation energy of diffusion of F-lysozyme molecules on a SiO_2 substrate is almost same as that on a glass substrate, in contrast, the activation energy of desorption of F-lysozyme molecules from a SiO_2 substrate is smaller than that from a glass substrate. These experimental findings were compared and examined with those of molecular dynamics simulations to establish computer simulation technologies.

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By investigating the interactions between luciferase and Si substrates using molecular dynamics (MD) simulation, we got the following results. Luciferase adsorbs directly on the hydrophobic Si substrate, and via water molecules on the hydrophilic one. Luciferase adsorbs more strongly on the hydrophobic Si substrate than on the hydrophilic one. Flexibility of luciferase is reduced when luciferase adsorbs on the Si substrate.

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We numerically investigate migration of biological polymers through a microchannel with periodically spaced electrodes. The numerical model is based on Brownian dynamics simulation of bead-spring chain. Electric potential inside the channel is determined by solving the linearized Poisson-Boltzrnann equation using the boundary element method. In this study, we mainly discuss mobility of biological polymers which would depend on the chain length of the model and on voltage of the electrodes. The present numerical technique would provide useful suggestions for future researches and basic design tools for practical μ-TAS devises.

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Wafer interface and wafer processes based on interactions between incident particles from plasma and the surface will be one of the practical issues in the era of nano-scale device fabrications. The prediction will be performed through a series of multi-scale modeling over nm-m in space and over ps-ms in time. Examples of the present status will be discussed based on a continuum model and hybrid (fluid+particle) model.

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Low temperature plasmas have been widely used in materials processing such as etching, sputtering, and ashing. The use of a low gas pressure is a recent trend in materials processing. Since the low gas pressure results in a large translational noneqilibrium, the particle modeling of processing plasmas has more sense. Here is given the state-of-art of the particle modeling.

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A computational fluid dynamics (CFD) model considering plasma and radiation was proposed to simulate three-dimensional (3D) ICP equipment consisting of multi-turn spiral coil antenna, coupling an rf (13.56MHz) field through a quartz window into plasma chamber. Since the gas temperature in the chamber can become a few times higher than room temperature for a largescale wafer processing and it has significant effect on the gas density, considering gas temperature is more important at a low gas pressure.

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A frame structural model is presented to study the elastic properties of carbon nanotubes (CNTs) under hydrostatic pressure. Simple formulae are given for the bulk modulus of CNTs under hydrostatic pressure as a function of chiral structures. The double-walled nanotubes are coupled together through the van der Waals force between the inner and outer nanotubes. According to this model, the effects of the CNT structures with the armchair and zigzag on the pressure behavior are investigated based on closed-form elastic solution. The computational result indicates that the bulk modulus is less sensitive to the nanotube structures except for very small tube diameter.

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