Transient absorption spectroscopy measures the changes in the absorbance of short-lived species generated by photo-irradiation, and gives us the information about dynamic processes in materials or chemical compounds. Rate constants are also determined by measuring time-profiles of the concentration of excited molecules.
By using this method, we can investigate molecular dynamics after photo-irradiation.

Developing efficient organic photovoltaic cell devices have been increasingly important in the growing needs for inexpensive renewable energy. The molecular designs for organic photovoltaic materials required delocalized pi-electron systems and utility elements. To develop novel pi-electron systems for organic photovoltaic materials, we synthesized some novel donor/acceptor arrays with aromatic bisimide units, and measured their properties and self-assembly abilities. Recently, we also synthesized some N-atom containing pi-electron systems and revealed their photophysical properties and structures.

We investigate various biological characteristics such as genetics, morphology, physiological reproduction, and nutrition of wild animals, especially small mammals, through breeding and preservation of their breeding stock (e.g., suncus and voles). To elucidate the diverse biosystems in humans and other animals, we aim to create unique animal resources that enable us to obtain knowledge that is difficult to obtain with common laboratory animals (e.g., mice and rats) and to improve their added value.

The final goal of our research is to converse with ants. Ants have long been thought to engage in detailed communication using chemical substances such as pheromones. However, our researchis revealing that acoustic signals are also important toos of communication.We conducte detailed analyses of organs such as “ears” and “sound-producing organs”. It will be able to control the behavior of ants like leaf-cutting ants, which are significant damage against human society.

We have been collaborating with various stakeholders such as the Fukuoka City, Fukuoka Prefecture, and the Ministry of the Environment to control invasive alien ant species such as the red imported fire ant, the yellow crazy ant, and Argentine ant. In Okayama Prefcture, there have been reported of the little fire ant (Wasmannia auropunctata) at Mizushima Port, and we will continue to control and manage these ants.

By using silk produced by silworms, which domesticated in China 6,000 years ago, and the silks spun by black Japanese weaver ant in Okinawa, we conduct research to create new fabric sheets. We hope that as this research progresses, the black Japanese weaver ant can be a symbolic relationship with humans as the fourth demesticated insect.

Japanese quail are the second most reared animal in the world poultry industry (meat and egg production), after chickens. Although suitable environments to improve productivity of domestic quail have been studied, not much is known about their biological characteristics, such as whether they are monogamous or polygamous, how females and males are involved in child rearing, and how they select partners. A better understanding of these issues will contribute to further improvement of quail productivity, and we are conducting behavioral and genetic research by actually raising and observing quail.
We also conduct population genetic and phylogeographic studies to understand how wild animals adapt to and live in their habitats, with focuses on wild animals.

Epithelial cells in spheroids formed through three-dimensional culture exhibit a quiescent state. Our research aims artificial interventions to control cell proliferation and differentiation during spheroid formation. Additionally, aiming for the standardization of cell culture techniques, we are advancing the development of a assessment system utilizing recorded videos.

We found that vagal hyperactivity produced by ventromedial hypothalamic (VMH) lesions stimulated cell proliferation of rat pancreatic islet B through a cholinergic receptor mechanism. Previously, we developed a new technique regarding high-quality RNA extraction from rat pancreas for cDNA microarray analysis, and thereby, we found that VMH lesions may change the expression of cell proliferation-related genes and neuron-related genes in a rat pancreas, using DNA microarray and real-time polymerase chain reaction. We believes that these new gene network analysis will lead to Diabetes MellitusTreatment or Pancreatic Cancer.

Various industrial products are made of solid materials such as metals, polymers, and ceramics. Although all solid materials deform elastically and plastically when forces are applied, their deformation behavior strongly depends on deformation mechanisms. Therefore, it is indispensable to understand their deformation properties to produce useful machines and durable apparatuses. Our laboratory has been working on subjects that aim to apply solid materials for various engineering applications; clarification and evaluation of deformation properties of engineering materials, study on influences of microstructure upon deformation properties of solids, and development of new forming techniques.

There exist three states of matter, i.e. gas, liquid and solid and a flow in which two or three of these states are mixed is called a multi-phase flow. We analyze the flow and heat transfer of multiphase flows using numerical simulations and visualization systems. The thermal flow in the garbage incinerator and the dough mixing in the noodle dough kneader are analyzed as a flow of mixed solids and gases. Bubbles generated in the molten solder bath are analyzed as a flow of mixed liquid and gas. For such problems, we use open source code e.g. OpenFOAM for simulation. In order to visualize heat and flow, PIV, large-diameter Mach-Zehnder interferometer, system schlieren, and infrared thermal image analyzer are utilized.

Mechanisms that allow humans to recognize and understand 2D drawings in 3D have long been actively studied in the fields of artificial intelligence and mechanical engineering. However, there is no real system until now. In our research, its automation methods have developed. Currently, the main themes are: (1) Sketches are often used to draw new ideas such as mechanical parts. We have developed a method to automatically convert them into 3D models. (2) In the civil engineering and construction industry, IT techniques are being promoted, but it is difficult until now. We have developed a system to automatically convert its 2D drawings into 3D models.

Machine elements such as screws, gears, bearings, shafts, and springs are components needed for mechanisms. The performance improvement of machine elements is essential for that of the mechanical device. Therefore, in the machine design laboratory, we work toward the high performance and high strength of machine elements in terms of materials, machining, and surface treatments. Specifically, we are working on the performance evaluation of plastic gears using gear testing machines, the rolling contact fatigue life evaluation of bearings with a ball-on-disk contact tester, the sliding characteristic evaluation of steel using a high temperature tribometer.

Bone histology is the study of internal bone tissues, and provides important clues to physiological and ecological aspects of extinct animals such as the growth rate, longevities, potential metabolism and aquatic adaptation.
I am currently conducting researches on bone histology of large tetrapods (e.g., dinosaur, mammal and amphibians) to understand their gigantism, dwarfism and aquatic adaptations.

The engine is an essential piece of machinery that is used in vehicles, electricity generators, ships, and so on. However, fossil fuels are limited in their amount and engines exhaust carbon dioxide from the burning of hydrocarbon-based fuels, which is treated as a cause of global warming. Therefore, in order to deal with these problems, an alternative fuel is proposed that is comparable to fossil fuel in terms of fuel properties such as ignitability, calorific value, cold flow properties and oxidation, but which is environmentally friendly. In this laboratory, a study is conducted on the production and optimal usage of alternative fuels such as biofuel (e.g., biodiesel), gaseous fuel, and so on. Combustion technology for engine systems for low fuel consumption rate using natural gas and hydrogen is also studied.

In order to improve the performance of various industrial devices and to make effective use of energy, it is important to understand and control the mechanisms of momentum, heat, and mass transport by turbulent flows. Understanding of turbulent transport phenomena is also essential for accurate prediction of meteorological phenomena. Our specific research topics include: experiments and numerical simulations to elucidate the mixing mechanism of scalars in liquid-phase turbulent jets; measurements of momentum, heat, and mass transport across wind-wave air-water interfaces to improve the prediction accuracy of typhoons; experiments to elucidate the behavior of droplets and bubbles in turbulent flows; and the development of novel devices (plasma actuators) to reduce fluid friction drag.

The mechanical and electro-magnetic characteristics of metals are dependent on microstructures such as crystal orientation and grain diameter. In recent years, comprehensive studies have been carried out on thermo-mechanical control processing to improve physical properties of metallic materials without adding rare elements in order to save energy and resources. For example, high performance metals, such as ultrafine grain steel and magnetic steel, are developed by a combination of rolling and heat treatment. These metals exhibit uniform characteristics. However, it is more efficient if suitable characteristics can be generated at required positions. In our research, a new technology to control only material surface microstructure is being studied.

In the case of metal materials are machined, the surface of materials are plastic defomed. Cristal structure of metal surface is strained by plastic deformation. The crystal structure strain changes the chemical property of surface. This phenomenon is called a mechano-chemical reaction. We study the mechano-chemical reaction and the relationship of machining process and material property.

1. Organic light-emitting materials for OLEDs or dyes for OPVs are developed.

2. Novel antiaromatic compounds such as Sondheimer-Wong diynes and diarenopentalenes are developed as new types of organic materials.

3. Organic syntheses using organotin cluster as catalysts are developed.

Numerical and experimental studies on transport phenomena, e.g. chemical reaction in beaker, indoor environment with air conditioner, natural environment, fluid flow and heat transfer in industrial equipment
■ patent number: 4931065
title of the invention: collision micro mixer
objective: increasing the chemical reaction efficiency by the collision of water and organic phases in the micro-channel
■ patent number 5504526
title of the invention: formation of slug flow with micro-reactor
objective: increasing the chemical reaction efficiency with the vortices generated by continuously changing the shapes of water and organic phases inside the micro-channel with zigzag walｌ

The interactions of surfactants with proteins have been widely studied. Recently, an attention has been paid to the effects of surfactants on the secondary structural changes of proteins denatured by another denaturing factor.

Biosensors using enzyme and antibody and biochips for using biosensor have been developed. For example, chemical agent sensor based on inhibition of enzyme activity and the RT-PCR biochip for rapid detection of COVID-19 have been studied.