Year: 2025
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Reliable pathfinding problems for a correlated network: A linear programming problem in a hypergraph
Kenetsu Uchida, Yifan Wang, and Ryuichi Tani
European Journal of Operational Research Volume 326, Issue 2, 16 October 2025, Pages 234-254
Broadband Phase Retardation with Palladium Coated Mirrors for M-edge XMCD in the 40–70 eV Range
Furkan Aksay, and Taro Sekikawa
Substituent Effects on Electrocyclic Reactions: Ultrafast Ring-Opening of α-Phellandrene Stimulated by Impulsively Excited Molecular Vibrations
Zhiyi Zhou, Kenichiro Saita, Yusuke Minegishi, Tetsuya Taketsugu, and Taro Sekikawa*
Superfluid dripping: a new analog for continuous time crystals
The dripping behavior of superfluid helium-4 has been found to be consistently discretized, even when flow rates vary. This unexpected phenomenon suggests that the superfluid dripping system exhibits time crystallinity by spontaneously breaking continuous time translation symmetry. The condition for the emergence of this continuous time crystal is that the edges of the pendant droplets, which hang from the underside of the cup, can move freely—a characteristic specific to superfluid dripping. This free motion leads to volume-independent oscillation periods for the droplets, effectively eliminating the influence of fluctuations in the flow rates.
Shota Takamatsu, Ryota Yamane, Tomoyuki Tani, Yuri Ishimoto, Keito Miyake, Yuki Aoki, and Ryuji Nomura
Collaboration on bulk-edge correspondence in gapless topological > phases
To significantly progress our joint research, we will invite a researcher from the Indian Institute of Technology Bombay to engage in 11 days of in-person discussion focused on bulk-edge correspondence and in gapless topological phase and effects of disorders. We also plan to discuss future application plans aimed at continuing collaborative research.
Hideaki Obuse (researchmap.jp, scholar.google.de), Soumya Bera, Ranjith R. Kumar, and Ishita Modak
JST Sakura Science Program (B course) 2025.8.21～2025.8.31
High-harmonic generation of by topological magnon edge states
Theoretical and experimental research on high harmonic generation originating from topological edge states of magnons is conducted.
Hideaki Obuse (researchmap.jp, scholar.google.de), and Hirori Hideki
Construction of an Energy Forecasting GIS and Development of Design Methods for Power Sharing Networks Utilizing Existing Buildings
Moving forward, Japan’s decarbonization must be driven by efforts that capitalize on the distinct characteristics of each region. Our research aims to develop a tool for predicting energy consumption in large building groups and evaluating the availability of renewable energy. In parallel, by proposing an optimized design methodology for power interchange networks that facilitates efficient electricity use, we will make it easier to formulate the best decarbonization plans tailored to specific regions.
Grant-in-Aid for Early-Career Scientists 2025.4.1～2028.3.31
A study on the application of accelerated carbonation cement paste powder by wet-dry cycle technique to supplementary cementitious material
Carbonated recycled concrete paste can serve as a supplementary cementitious material (SCM) with pozzolanic properties from alumina-silica gel. Additionally, since it contains fine particles of calcium carbonate, it is expected to enhance concrete performance through its filling effect when used as SCM. Previous studies have shown that the wet-dry cycle method promotes CO₂ absorption and increases the porosity of concrete paste. Based on this, the study aims to efficiently absorb CO₂ using waste concrete paste through the wet-dry cycle method and seeks to recycle resources and enhance concrete performance by reusing the carbonation products as SCM.
Dayoung OH (researchmap.jp, researchgate.net, scholar.google.com), and Ryoma KITAGAKI
The Taisei Foundation 2025.4~2026.3
Research and Development of Anomaly Detection Technology for Civil Infrastructures Using Electret Vibrational Energy Harvesting Device and Wireless Power/Data Transfer
We will develop a battery-less anomaly detection device capable of sensing the condition and environment of infrastructure structures, and establish a wireless energy and data communication platform. In particular, a system will be realized that allows monitoring via an IoT network using microwave spatial transmission (WPDT) technology of information related to structural deterioration, damage, environmental conditions, and faults autonomously detected by electret MEMS sensors powered by environmental vibration energy harvesting. This will enable the social implementation of a seamless monitoring platform targeting infrastructure structures and their auxiliary facilities, capable of phase-free response at all times, including both normal and emergency conditions.
Katsufumi Hashimoto (PI), Hiroyuki Mitsuya, and Teruo Fujiwara
Material Behavior and Mechanical Performance Based on Hierarchical Structure Formation of 3D-Printed Concrete
This study investigates the hierarchical structure of 3D-printed concrete (3DP concrete) by analyzing two key aspects: the microscopic heterogeneity caused by material segregation within the filament during deposition, and the macroscopic non-uniformity resulting from interfacial voids formed along the printing path. By clarifying these higher-order structures, we demonstrate that 3DP concrete possesses multiscale material properties and mechanical behavior, making it a hierarchical material. Furthermore, we establish a systematic academic framework for understanding how heterogeneity (material geometry) and non-uniformity (structural geometry) are embedded as geometric parameters in 3D spatial information, providing insights into the mechanical performance and failure modes of 3DP concrete.
Katsufumi Hashimoto, Takafumi Sugiyama, and Shimpei Ono
Grant-in-Aid for Scientific Research(B) 2025.4.1～2028.3.31