Volume 1, 2025
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Development of radiation technology to clarify the microstructure of concrete, which is becoming more diverse in a decarbonized society
Concrete, the main construction material, is the second most widely used substance after water. As concrete has a large environmental impact on a global scale, we are conducting research at the ultrafine level of its internal structure of concrete using advanced radiation technology to develop a new type of concrete that reduces the emissions of carbon dioxide and other gases that accompany its manufacture, without compromising its strength or durability. In this way, we can achieve a decarbonized society.
Takafumi Sugiyama, Katsufumi Hashimoto, and Michael Angelo B. Promentilla,
Grant-in-Aid for Scientific Research(B) 2025.4.1～2028.3.31
Imaging valley-vortex edge modes in a phononic crystal at ultrahigh frequencies
We perform optical measurements and numerical simulations of guided phonon propagation in novel topological phononic crystal structures at ultrahigh frequencies. The structures support valley-polarized states that exhibit an energy vortex nature and propagate with high efficiency at domain boundaries because backscattering is suppressed due to conservation of time reversal symmetry. We extract frequency- and time-resolved spatial mode patterns and -space images, together with dispersion relations. We investigate the conditions required for robust propagation along interfaces and thereby observe very high efficiency waveguiding.
Paul H. Otsuka, Motonobu Tomoda, Daiki Hatanaka, Hiroshi Yamaguchi, Kenji Tsuruta, and Osamu Matsuda
Development of dimension reduction scheme for data assimilation using criticality experiments
The nuclear cross section uncertainty given as a covariance matrix will be used to evaluate the realistic range of important parameters in the safety analysis of nuclear reactors. In recent discussions, the application of data assimilation is considered important to incorporate criticality experiment findings. However, there is a practical issue to treat the covariance matrix after applying data assimilation because the covariance matrix becomes much denser one by causing complex correlated components and the computational cost becomes increased. This research project develops a dimension reduction scheme to solve this practical issue.
Principal investigator: Tatsuya Fujita, and Collaborator: Go Chiba
Grant-in-Aid for Scientific Research(C) 2025.4.1～2029.3.31
Study of Quantum Plasticity and Supersolidity of solid 4He by Observing Motion of Sinking Object
Solid helium is often referred to as quantum solid and known to deform easily and rapidly even under tiny force, strongly subjected to quantum effect. A number of research have been conducted to study its elasticity, or reversible deformation, but its plasticity, or irreversible deformation, is scarcely understood. In the proposed experiment, we are going to precisely measure the motion of objects sinking in solid helium to elucidate the quantum effects on the plasticity of solid helium. Especially, the local superflow expected to exist in cores of dislocations and grain boundaries are to be examined, in the context of supersolidity.
Grant-in-Aid for Early-Career Scientists 2025.4.1～2028.3.31
Pore properties and CO₂ adsorption performance of activated carbon prepared from various carbonaceous materials
The production of activated carbon using biomass and coal as carbon sources, melamine as a nitrogen source, and K₂CO₃ as a chemical activator revealed that the lower carbon content and lower ash content of the carbon source resulted in better pore development, and that the surface area and micropore volume of activated carbon affected the CO₂ adsorption capacity. It was also shown that the optimal micropore size for CO₂ adsorption is 0.5 to 1.2 nm. These results are expected to lead to the establishment of production guidelines for activated carbon with high CO₂ adsorption capacity.
Yuuki Mochizuki, Javzandolgor Bud, Enkhsaruul Byambajav, and Naoto Tsubouchi
Mechanisms underlying the dynamic strength of cancellous bone based on the impact strength of individual trabeculae and microarchitecture
Osteoporotic fractures occur in cancellous bone due to even minor impacts. In addition to bone mass, the impact strength of individual trabeculae and the microarchitecture are hypothesized to determine the dynamic strength of cancellous bone. This study aims to experimentally clarify these mechanisms and apply the findings to further improve the control of dynamic fracture risk.
Satoshi Yamada, Tomohiro Shimizu and Kazuhiro Fujisaki
Grant-in-Aid for Scientific Research(B) 2025.4.1～2028.3.31
Development of a 3D-printable head protection material with superior impact absorption and durability using biomimetic porous structures
We are developing a novel 3D-printable head protection material using a biomimetic structure inspired by cancellous bone architecture. This offers excellent multi-impact absorption capabilities. Its high three-dimensional isotropy enables it to absorb impacts from any direction. The porous design can be freely tailored to meet specific shape and performance requirements. In addition to head protection, the material shows strong potential for applications in body protection gear and cushioning materials for transporting precision equipment.
Satoshi Yamada, Yuelin Zhang, and Keita Kawashima
Adaptable and Seamless Technology transfer Program through Target-driven R&D (A-STEP) 2024.12.1～2027.3.31
Selective separation of Li, Ni, Co and Mn from model spent Li ion battery cathode materials by dry processing using the combination of chlorination and oxidation
The present group has recently developed a technology to selectively recover valuable metals (Li, Ni, Co and Mn) from used lithium-ion battery cathode materials (LiNiO₂, LiCoO₂, LiMn₂O₄, and their composite composition). Specifically, we found that Li, Ni, Co and Mn can be selectively separated from LiNiO₂, LiCoO₂, and LiMn₂O₄ by chlorination up to 600℃ followed by air oxidation up to 1300℃. This research paper was selected as a Key Scientific Article by the selection committee of Advances in Engineering, Canada, and is highly evaluated.
Novel continuous-time crystallinity observed in a superfluid dripping system
While the dripping period of a classical viscous fluid is widely distributed due to the influence of chaos, the dripping period of a superfluid 4He liquid is discretized to a constant value specified by integers even if the inflow rate changes. We clarify that this robust discretization is the realization of a continuous-time crystal from the viewpoints of inflow rate phase diagram, temperature phase diagram, wall shape and dimensionality, and time-domain phonon excitation.
Ryuji Nomura, Tomoyuki Tani, and Yuki Aoki
Grant-in-Aid for Scientific Research(B) 2025.4.1～2028.3.31
One-Pass Synthesis of BTX from CO₂ Enabled by Precisely Controlled Catalysts
CO₂ utilization is essential for achieving carbon neutrality, and among potential target products, BTX (benzene, toluene, and xylene) are key basic chemicals in a post-fossil society. In this study, we build on previous collaborative research between the University of Tokyo, Hokkaido University, and Idemitsu Kosan Co., Ltd. We aim to precisely control the catalyst structure at the atomic level, enabling one-pass synthesis of BTX from CO₂. Through this approach, we seek to establish a catalyst process that is robust and scalable, suitable for industrial application, and capable of supporting a sustainable future without reliance on fossil resources.
Shohei Tada, Kotaro Takeyasu, Ryota Osuga, Kenta Iyoki, Yuichiro Kanematsu, and Idemitsu Kosan Co., Ltd.
NEDO Feasibility Study Program (2025~)