Flock finishes for exhibition displays, which are prepared to custom-made specifications, are difficult to create in an existing mass production line so a hand-held portable flocking machine is used. In order to perform high quality flocking with this machine it is important to determine the optimum flocking distance between the machine and the flocked object. However, the know-how of a skilled worker is needed to realize this at the field site. In the present study, as the flocked objects for exhibition displays, a sphere, a cylinder and a cone were selected. In order to be able to carry out high quality flocking with a handheld portable machine even if the worker skill and know-how is poor, a 3D-capable electrostatic field simulation was utilized to determine the optimum flocking distance of the above objects. To confirm the validity of the simulation result, flock finishing was carried out using analysis values obtained by the electrostatic field simulation.
Melanin plays an important role in structural colors in nature. Recently, we have focused on the use of polydopamine as a mimic of melanin to produce structural color materials. Here we outline our recent work on structural color materials based on artificial melanin particles. We have shown the preparation of biomimetic structural color materials inspired by a color of peacock feathers. Since artificial melanin particles act as a component of a structural color material and as a scattering absorber, high visibility structural color materials can be produced with a single component. This simple and novel process of using artificial melanin particles will be used in basic research on structural colors in nature and ink applications.
About 30 years have passed since the lithium ion batteries (LIBs) were put to practical use as a power source for portable electronic devices. Nowadays, LIBs are expected to be widely used and deployed in electric vehicle applications, and has become an essential power source technology for realizing a low carbon society. An important component for battery technology is the positive electrode, and lithium cobalt oxide, which was first used, is still an important positive electrode active material today. We will review the history of historical material development from the basic physical properties of positive electrode materials.
Conductive inks and pastes consisting metal particles dispersed in an organic solvent have attracted extensive attentions for manufacturing electronic devices. Thus, development of metal particles that are stably dispersed in ink and can be sintered at a low temperature is indispensable to realize printed electronics technology. To prepare such metal particles, it is essential to synthesize monodispersed particles with the adequate surface design. Pulverization prior to ink formation becomes also important for imparting long-term stability. Copper is a promising material due to its low cost and electro-migration resistance. We have developed low-temperature sintering copper fine particle inks with long term stability by surface protection and unform dispersion of copper fine particles.