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.

(Summary of our study)
The central goal of our group is to develop the new synthesis method of inorganic materials using water-soluble complexes and to search a new functional inorganic materials such as phosphors and transparent conducting materials, superconducting materials and so on.

(Main topics: Development of new phosphors)
Main topics of our study is development of new phosphors activated by blue and near-UV lights. Recently, we have reported new deep red-emitting oxide phosphors activated by blue light. We also investigate high functionalization of new host-excited phosphors based on functional oxides contained metal ions with s⁰ electron configuration.

Our research theme is development of new photoreaction using photoinduced electron transfer and its application to syntheses of functional materials. In present, we are working on (1) investigation of photochemical syntheses of indole derivatives which are considered to the important alkaloids widely found in nature, and (2) development of efficient photochemical synthetic methods for quinone imine dyes and their application. Because these target compounds indicate characteristic redox behavior, we also consider applying them to functional materials such as an OLED material while adopting their expected physical properties evaluated by quantum chemical calculation.

The kinds of polymers are relatively a few, which are used as plastics, rubber, and gels for daily life, since they exhibit versatile properties by hierarchical structure control ranging from nano- to micro-meter scales. In our laboratory, we focus to develop new polymeric materials by the hierarchical structure control and reveal the relationship between the mechanism and structure by microscope, scattering, and spectroscopy methods.

I’m working on migration behavior of elements in hydrosphere from a chemical view.

【Elucidation of mechanism of solid-liquid interfacial reaction】
One of the factors affecting migration behavior of elements in environment (especially in hydrosphere) is “adsorption of dissolved species on soil”. In recent years, it has been reported that various reactions to the adsorbed species occur. I’m trying to elucidate the mechanism of the reaction.

【Elucidation of nature of dissolved species in hydrosphere】
The dissolved species in hydrosphere is complex because several dissolved species coexists. I’m trying to elucidate the nature of the complicated dissolved species with theoretical calculation.

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.

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.

Hepatocyte growth factor (HGF) was originally identified as an hepatotrophic factor. During the past 30 years, we provided evidence to show that HGF plays an essential role for regeneration of several types of organs, including kidney, lung, hearts and neural tisses, using animal models of intractable disorders. HGF elicits unique biological activities, such as mitogen, motogen and morphgen via activating c-Met/HGF-receptor tyrosine kinase as shown below. Of note, a loss in HGF production is responsible for manifestation of acute and chronic organdiseases. This is the reason why HGF supplemental therapy produces benefit effects against the progression of acute and chronic organ diseases.

The coypu (Myocastor coypus) is a large-sized rodent introduced from South America, and has been designated as a specific alian species since 2005 by Japanese government. However, the knowledge of its biological charateristics necessary for pest control is scanty. Thus, we are coducting related research on the coypu from various angles. We have revealed that the coypu has a high level of learning capability. It also has a high physical potential, such as climbing over a fence about 70 centimeters tall. In the historical aspect, we have also revealed that the background for the spread of the species in Japan has not been as has been told before. There was a nationwide campaign for promotion of the propagation of the coypu for meat production increase in the WWII postwar food shortage period.

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.

Primates (precisely non-human primates), are the animal group that shares the most similarities with humans. They show high levels of intelligence and social skills. Additionally, many primate species live in tropical and subtropical regions and are considered keystone species that play a fundamental role in maintaining tropical ecosystems. Researching the society and ecology of primates can provide us with valuable insights into the evolution and nature of humans. This knowledge can help us better understand ourselves, as well as contribute to the conservation of biodiversity and the resolution of global environmental issues. My work involves studying the society and ecology of primates and other large and medium-sized mammals, mainly through field observations. I also examine human society from a zoological perspective and its evolution. Currently, my team and I are conducting long-term field research and conservation activities to protect wild gorillas in the tropical forests of Central Africa. We also conduct educational and animal welbeing activities in zoos and perform behavior observation research on Japanese macaques in Japan.

We focus on the ecology of wild animals, including endangerd species, and their function in the ecosystem using direct observation or research tools such as camera trap. We explore better conservation methods and way for a sustainable coexistence with people.

Mammanlian reproductive status changes during postnatal development and aging. It can also be altered by environmental cues, stress or dysfunction of related organs. My research aims to clarify the factors and the mechanism which affect reproductive functions by using histological analysis on hypothalamic-pituitary-gonadal axis and measuring reproductive hormones. I am also working to establish methods to monitor reproductive status of wild animals by measuring steroid hormones in hair.

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.

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.

Examination of production conditions for soft magnetic amorphous ribbons by liquid rapidsolidification method using precipitation hardening Cu alloy rolls. In this paper, we investigated that production conditions for amorphous ribbons by liquid rapid solidification method.

In recent years, composite and polymeric materials have been increasingly replacing conventional metallic materials in aerospace, civil, marine, rail and automotive industries. Some applications of composite and polymeric materials involve dynamically loaded components and structures. Therefore, there is a need to fully understand the dynamic behavior of composite materials for the analysis and design of composite and polymeric structures subjected to impact loadings. However, the mechanical properties of composite and polymeric materials under dynamic loading conditions are not well understood, because there are no standard impact test techniques.
Consequently, we experimentally and numerically examine the effects of strain rate on the compressive and tensile characteristics of composite and polymeric materials. High strain-rate stress-strain curves are obtained on the standard or modified split Hopkinson pressure bar (SHPB). Low and intermediate strain-rate ones are measured in an Instron testing machine.

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.

Studies on Control Strategy for Multi-body Systems
We can take each of the machines as a system that is composed of many parts including adjacent parts that are connected by a joint so that they can move relative to each other. We can typically assume that each part is rigid enough that it will never bend or twist while in motion. Such a part is called a rigid body. We can consider industrial robotic arms and even automobiles as systems with rigid bodies. When the rigid bodies in the system move, various forces are applied to the system from the inside. Then, we must ask, what is the relationship between the forces and the motions of the rigid bodies? In the control engineering laboratory, we study such problems for mechanical systems and try to control or measure the mechanical values of the system in order to obtain effective control methods.
Studies on Dynamic Mass Measurement
We also try to obtain effective estimation methods for some mechanical values of the system (including total mass) based on dynamics. Solving the problem of measuring the weights of heavy in-motion vehicles with high precision belongs to the field of dynamic mass measurement.

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.