National Institute of Advanced Industrial Science and Technology

About: National Institute of Advanced Industrial Science and Technology is a government organization based out in Tsukuba, Ibaraki, Japan. It is known for research contribution in the topics: Catalysis & Thin film. The organization has 22114 authors who have published 65856 publications receiving 1669827 citations. The organization is also known as: Sangyō Gijutsu Sōgō Kenkyū-sho.

Photo-Switched Storage and Release of Guest Molecules in the Pore Void of Coumarin-Modified MCM-41

Abstract: A photoresponsive coumarin derivative was grafted on the pore outlet of Si−MCM-41. Irradiation of UV light longer than 310-nm wavelength to this coumarin-modified MCM-41 induced the photodimerization of coumarin to close the pore outlet with cyclobutane dimer. Guest molecules such as phenanthrene neither can enter nor escape from the one-dimensional, isolated, individual pores of MCM-41. On the other hand, the irradiation to the dimerized-coumarin-modified MCM-41 with shorter wavelength UV light around 250 nm regenerates the coumarin monomer derivative by the photocleavage of cyclobutane dimer, and guest molecules included inside are released from the pore void. For the first time, this intermolecular reversible photodimerization−cleavage cycle realized photo-switched storage and release of guest molecules from coumarin-modified MCM-41. Coumarin-modified MCM-41 prepared using tetradecyltrimethylammonium bromide as surfactant was able to store 21.6 wt % of phenanthrene as guest molecule after photodimeriza...

Dynamics of efficient electron-hole separation in TiO2 nanoparticles revealed by femtosecond transient absorption spectroscopy under the weak-excitation condition.

Abstract: The transient absorption of nanocrystalline TiO2 films in the visible and IR wavelength regions was measured under the weak-excitation condition, where the second-order electron–hole recombination process can be ignored. The intrinsic dynamics of the electron–hole pairs in the femtosecond to picosecond time range was elucidated. Surface-trapped electrons and surface-trapped holes were generated within ∼200 fs (time resolution). Surface-trapped electrons, which gave an absorption peak at around 800 nm, and bulk electrons, which absorbed in the IR wavelength region, decayed with a 500-ps time constant due to relaxation into deep bulk trapping sites. It is already known that, after this relaxation, electrons and holes survive for microseconds. We interpreted these long lifetimes in terms of the prompt spatial charge separation of electrons in the bulk and holes at the surface.

A 3-D self-reconfigurable structure

Abstract: A three-dimensional, self-reconfigurable structure is proposed. The structure is a fully distributed system composed of many identical 3-D units. Each unit has functions of changing local connection, information processing, and communication among neighborhood units. Groups of units cooperate to change their connection so that the shape of the whole solid structure transforms into an arbitrary shape. Also, the structure can repair itself by rejecting faulty units, replacing them with spare units. This kind of self-maintainability is essential to structure's longevity in hazardous or remote environments such as space or deep sea where human operators cannot approach. We have designed and built a prototype unit to examine the feasibility of the 3-D self-reconfigurable concept. The design of the unit, method of reconfiguration, hardware implementation, and results of preliminary experiments are shown. In the last part of the paper, distributed software for self-reconfiguration is discussed.