• Our research group investigates creation of functional oxides and their functionalities. We synthesize thin films by pulsed laser deposition and sputtering methods and bulk specimens, and develop their novel synthetic routes. Recently, we are studying electrically conducting rare earth oxides, transparent room temperature ferromagnetic semiconductors, and layered superconductors with monatomic Bi layer. We will develop our materials design by extending materials range and performing oxide heteroepitaxy.

Collaborative research in fields of oxide electronics with novel electric conducting oxides and oxide spintronics with ferromagnetic semiconductors and novel ferromagnetic oxides.

• One of the important challenges in the development of carbon nanotubes (CNTs) reinforced ceramic composites is uniform dispersion of CNTs in the matrix. The mechanical properties of CNT/ceramics composites have been limited to date due to the formation of CNT agglomerates in the composite. We have successfully produced CNT/alumina composites with world top class strength and toughness, by employing a newly developed CNTs dispersion technique based on a flocculation method. The processing method developed in this study enables us to prepare high performance CNT materials using a pressureless sintering method.

The possible applications of the CNT/alumina composites developed in this study include tribological materials (ball bearing), biomaterials (artificial hip joint), micro-actuator materials utilizing electrostrictive effects, electromagnetic wave absorber, particularly in the frequency range of several GHz and several ten GHz.

• Hybrid materials that show multi-functions of polymer and nanoparticles are expected to be used in future industries, and thus many research and development have been actively conducted. However, since the affinity of polymer and inorganic nanoparticles is very low, in most of the cases, properties of different materials are incompatible in the hybrid materials. To create the hybrid materials with incompatible multi-functions has been considered a difficult task.
• However, by using supercritical fluid technology, we have succeeded in making hybrid materials with incompatible multi-functions.

Now, variety of hybrid materials are being developed, including
・Transparent, flexible, high reflective index, and high fabricability,
・Flexible, high heat conductivity, low electric resistivity, and high fabricability.

• Our research aims at developing methods, including instrumentation, for characterizing surface (or interface) at the nano-meter level. Most of our research subjects are related to the surface forces measurement, which can directly monitor the interaction between two surfaces. We study phenomena occurring at the solid-liquid interface such as adsorption and structuring of liquids. We have developed the resonance shear measurement which is a sensitive method for evaluating properties of confined liquid for nano-rheology and tribology. Twin-path surface forces apparatus we developed enabled us to study wide variety of samples such as metals, ceramics and plastics.

These methods are applicable for characterizing lubricants, nano-materials, paints, sealants, and cosmetics. We hope to conduct collaborative research with a willing company for a practical application of this technology in industry.

• We developed both pH and Cl- imaging plates, which can visualize the pH and Cl- concentration on metal surfaces in acidic environments. The pH range is from 3.0 to 0.5, and Cl- concentration up to 4 M can be measured. Fluorescent dyes are successively used for pH and Cl- imaging in the field of biology, but their sensitivity tends to be insufficient in acidic and/or highly concentrated chloride solutions. A glass plate with a sol-gel sensing layer, which contains a pH indicator or a Cl- sensitive florescent dye was fabricated and validated using the solutions with various pH values and Cl- concentrations. Changes in the pH and Cl- distribution on stainless surface in an acidic environment were measured quantitatively.

The newly developed imaging plates can be used to investigate the mechanism of various chemical reactions, such as corrosion, which occurs in an acidic environment. Micro-flow imaging using our sensing technique will be a promising approach to understand the catalytic chemistry of metal surfaces.
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