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The self-assembly of flexible bolaamphiphilic molecules in a solution is studied by dissipative particle dynamics simulations. In particular, we investigate the effect of the interaction difference, Δa, between the two different hydrophilic end groups on the self-assembly in a bolaamphiphilic solution. Our simulations show that two types of self-assembled structures, spherical vesicles and worm-like micelles, are obtained from a random configuration of bolaamphiphilic molecules in a solution. We find that the worm-like micelles are formed when Δa > 0, whereas spherical vesicles are obtained when Δa ≤ 0. It is also ascertained that the size of the spherical vesicles decreases as Δa decreases.

This study aims to create an interface for visualizing numerical data on a head-mounted display (HMD) and introduce functions to allow control of this visualization via hand gestures. HMDs have the advantage of providing a user with a 360-degree field of view without taking up a lot of space. However, it is difficult to control visualized numerical data intuitively with this type of display because the user cannot see his/her own hand. We therefore introduced functions allowing the user to control the virtual scene with visualized virtual hands. We developed a system in which a virtual menu is presented to the users and they can change the visualization method by pushing virtual panels. The user can move freely in the visualized virtual scene. Moreover, to help users share their thoughts, we have introduced a drawing function that enables users to indicate points and areas of interest in the visualized scene.

The phase behavior of bolaamphiphilic solutions is studied by coarse-grained molecular dynamics simulations of semiflexible bolaamphiphilic molecules with explicit solvent molecules. Our simulations show that six kinds of self-assembled structures (spherical micelles, worm-like micelles, bicontinuous structure, hexagonal structure, plate-like micelles, and lamellar structure) are obtained. It is established that, at low concentrations, a plate-like micelle changes to worm-like micelles, and then to spherical micelles as the hydrophilic interaction increases. Conversely, at intermediate concentrations, a lamellar structure changes to a bicontinuous structure; it then changes to worm-like micelles or a hexagonal structure as the hydrophilic interaction increases. It is also observed that the global orientational order parameter for the end bonds of bolaamphiphilic molecules can be used to clearly distinguish between the randomly-oriented structures (the spherical micelles, the worm-like micelles, and the bicontinuous structure), the lamellar structure, the hexagonal structure, and the plate-like micelles.

Micellar shape change in an amphiphilic solution is investigated by a molecular dynamics simulation of coarse-grained semiflexible amphiphilic molecules with explicit solvent molecules. Our simulations show that a cylindrical micelle is obtained at small molecular rigidity while a disc-shaped micelle appears at large molecular rigidity. We find that most chains are in an extended conformation at large molecular rigidity whereas the fraction of the chains in a bent conformation becomes large at small molecular rigidity. It is also ascertained that the micellar shape starts to change immediately after sudden increase of the molecular rigidity while an induction time is needed to change the micellar shape after sudden decrease of the molecular rigidity. This result can be qualitatively explained by considering the bond-bending potential energy and the conformational entropy of the amphiphilic molecules.

When we design and construct a large-scale device, it is very important to confirm the interference among its parts. We might need to confirm not only the interference among the parts that are designed at the start but also the interference with some parts that are added after construction. However, sometimes even on using 3D CAD, we cannot detect the interference or the collision among parts, particularly when these parts form a complex 3D shape. On the other hand, virtual reality devices have been used in various fields such as design support systems; however, real-time collision detection among complex parts has been difficult to achieve. We constructed a system that can detect collision and interference in real time in a virtual reality system. This engine can detect interference between polygons. This enables to calculate more accurately than voxel-based detection engine. Moreover, we propose a dynamic interference vector for removing interference. This vector is defined as a local minimum vector which removes the interference from the same edge where the contact starts. This method enables to prevent an object moves discontinuously, when the interference is removed. Finally, we introduced an example of using this system for assembling parts.

We study the phase behavior of bolaamphiphilic solution performing the dissipative particle dynamics simulations of coarse-grained bolaamphiphilic molecules with explicit solvent molecules. Our simulations show that there are six kinds of phases: isotropic micellar, micellar, rod-shaped micellar, hexagonal, network-structure and lamellar. The network-structure and the lamellar phases disappear when the restoring potential against the bending of bolaamphiphilic molecules in our simulation model is excluded; and the isotropic micellar and the hexagonal phases disappear when the restoring potential is included. This suggests that the bending potential is important in the formation of the higher-ordered structures by the bolaamphiphilic molecules.

Micelle formation in an amphiphilic solution is investigated by a molecular dynamics simulation of coarse-grained semiflexible amphiphilic molecules with explicit solvent molecules. Our simulations show that the micellar shape changes from a cylinder to a disc as the intensity of the molecular rigidity increases. We find that the radius of gyration of the cylindrical micelle is larger than that of the disc-shaped micelle for small molecular rigidity, although the radius of gyration is almost steady even during the transition between a cylinder and a disc for large molecular rigidity. This indicates that a cylindrical micelle formed at small molecular rigidity is more anisotropic than the one obtained at large molecular rigidity. We also ascertained that a cylindrical micelle and a disc-shaped micelle coexist dynamically over a certain molecular rigidity range.

Thermal display, which is a type of haptic display, is effective in providing intuitive information of temperature. However, in many studies, the user has assumed a sitting position during the use of these devices. In contrast, the user generally watches 3D objects while standing and walking around in large-scale virtual reality system, In addition, in scientific visualization, the response time is very important for observing physical phenomena, especially for dynamic numerical simulation. One solution is to provide two types of thermal information: information about the rate of thermal change and information about the actual temperature. We propose a thermal display with two Peltier elements which can show above two pairs of information and the result (for example energy and temperature, as thermal information) of numerical simulation. Finally, we represent an example of visualizing and haptizing the result of molecular dynamics simulation.