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Natural Sciences


Separation, purification and recovery of rare metals by means of electrodialytic ion transfer device

OHIRA Shinichi, Faculty of Advanced Science and Technology

Rare earth elements are defined not only by the trace amounts found in the earth but also by the difficulty of purification and recovery. The need to recycle elements will dramatically grow in the coming decade because of shortened product lifetimes. In this project, the recovery of elements from used Li-batteries is studied. The electrodialytic ion transfer device, which can transfer ions quantitatively between solution phases, is applied for purification, especially for the separation of cobalt and nickel. The study is aimed at developing a highly effective and clean recovery method that is free of toxic chemicals.
 


Are moss chloroplasts surrounded by a wall?

TAKANO Hiroyoshi, Faculty of Advanced Science and Technology

It is now widely accepted that an endosymbiotic cyanobacterium evolved into the plastids of green plants. Although free-living bacteria typically have peptidoglycan in their cell wall, it is believed that the plastids of green plants lost endosymbiotic peptidoglycan during evolution. We isolated a homolog of the bacterial peptidoglycan-synthetic gene encoding D-alanine (D-Ala):D-Ala ligase from the moss Physcomitrella patens. Generated knockout transformants showed disrupted chloroplast division and giant chloroplasts, and the phenotype was recovered by the addition of DA-DA. Using a metabolic labeling method for peptidoglycan with a DA-DA dipeptide probe and click chemistry, we visualized plastid peptidoglycan fully surrounding the chloroplasts of the moss. Our findings suggest that the plastids of basal land plants have a peptidoglycan wall.
 


Processing technology for creation of bio-inspired surface to various materials

NAKANISHI Yoshitaka, Faculty of Advanced Science and Technology

The biomechanisms of the lotus leaf and moth eye have been explored. In particular, the relationship between their structures and their water-repellency effect and reflection suppression have been elucidated. These studies have contributed to the development of innovative industrial products. The microscopic structure seen on a natural surface is generally created by a nanoimprint method based on semiconductor manufacturing technology, so some limitations must be considered in terms of product size, shape, and material. This study aims to explore surface micromachining, a mechanical material removal process that serves as an alternative to a nanoimprinting, in creating a bio-inspired surface on artificial materials.
 


Material design of ammonia combustion catalysts based on mullite type crystal structure

HINOKUMA Satoshi, Faculty of Advanced Science and Technology

This study focuses on the material design of novel catalysts for the combustion of ammonia, which has potential as a renewable and carbon-free energy source. The target catalyst is based on a mullite-type crystal structure with high thermal stability, and enables the low-temperature light-off of ammonia and negligible emissions of nitrogen oxide to realize environmentally friendly catalytic combustors for ammonia fuel. The use of ammonia as potential substitute for fossil fuel resources can be advanced by knowledge gained from this study.
 


Development of Zr- and Hf-based high temperature shape memory alloys by the addition of B and rare earth elements

MATSUDA Mitsuhiro, Faculty of Advanced Science and Technology

Martensitic transformation behavior and microstructure in shape memory alloys and B2-type intermetallic compounds, such as zirconium- and halfnium-based alloys, have been investigated using transmission electron microscopy (TEM) and X-ray diffractometry. We have clarified the microstructural features using synchrotron radiation and TEM analysis in Ti-Pd, Ti-Pt and ZrCobased alloys subjected to high pressure torsion. Their functional properties are based on a martensitic phase transformation that can be strongly affected by disordering, and are grain-size at nanoscale.
 


Science and Engineering of Carbon Nanopot

YOKOI Hiroyuki, Faculty of Advanced Science and Technology

The carbon nanopot (CNPot) is a novel pot-shaped nanomaterial, recently invented using our original submarine-style chemical vapor deposition technique. It is produced in series to form long fibers from which each nanopot is easily separable. Our study has also suggested that CNPot is amphiphilic. These features make CNPot a promising tool for application in drug delivery systems, gas or bio-sensors, functional hybrid materials, electrode materials for high-performance batteries, and more. We also expect that the unique nanostructure of CNPot may offer yet undiscovered novel physical properties. Experimental and theoretical studies of this distinctive nanomaterial are intensively under way.
 


Elucidation of physical properties of optical functional materials in an extremely spatiotemporal reaction field

KOSUMI Daisuke, Institute of Pulsed Power Science

A timescale of femtoseconds (10-15 s) is comparable with the oscillation periods of nuclear motions, such as molecular vibrations and lattice vibrations. Ultrafast spectroscopy enables us to observe the non-equilibrium dynamics of materials that take place at an extremely fast timescale. This project is aimed at elucidating the energy movement of optical functional materials under an extreme reaction field, by combining graphene plasmonics and ultrafast spectroscopic measurements.
 
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