In-situ observations using high-temperature transmission electron microscopy (TEM) are a promising technique for obtaining new findings and developing phenomenological theory for ceramic materials at high temperatures. Through observations of the grain growth of BaTiO₃, we calculate the grain-boundary diffusion coefficient, which is an important parameter controlling the sinterability of ceramics. Observations of the shrinkage process of Ba₅Nb₄O₁₅, as well as simulations, indicate that high energy and low diffusivity at the grain boundary make grains vanish while maintaining a truncated spherical shape. Finally, observations of the structural changes in layered perovskite BaGd₂Mn₂O₇ reveal a first-order phase transition that has not been previously reported.

Granular flow is a typical phenomenon that arises in slope disasters such as landslides and debris flows, and its runout distance is closely associated with the resulting damage. Therefore, predicting and evaluating the runout distance is essential for disaster prevention and mitigation. In recent years, the discrete element method (DEM), which can reproduce particle-scale behavior, has been widely utilized for such risk assessment. However, the runout distance of granular flow varies depending on many physical parameters and exhibits strong randomness, making its analysis challenging. The authors have previously published a study that investigated combinations of DEM parameters that are critical for efficiently estimating the maximum runout distance of granular flow through a series of DEM simulations. Specifically, dominant DEM parameters were first identified, and the relationship between their combinations and the runout distance was then analyzed. This article provides an explanatory overview of that study.

Cyclodextrin functions as a host molecule that can include external guest molecules in its hydrophobic cavity in water. In our laboratory, we have found that per-O-methylated β-cyclodextrin (TMe-β-CD) forms a stable 2:1 inclu­sion complex with 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS). The inclusion complex has a strong hydrophobic cavity around the porphyrin scaffold, similar to the environment of heme in heme proteins. We have synthesized a per-O-methylated β-CD dimer having pyridine linker (Py3CD) to make a biomimetic model compound of hemoglobin (Hb) and myoglobin (Mb). The inclusion complex of Py3CD with iron complex of TPPS (FeTPPS) is the first biomimetic Hb/Mb model complex in water. The complex, hemoCD, showed a very high CO binding affinity in vivo. When hemoCD was injected to animals (mice and rats) after exposure to CO, hemoCD captured CO during circulation and was excreted in urine without showing any toxic effect. These properties seem appropriate for the use of hemoCD as an inject­able antidote against CO poisoning. We have just started the drug development to implement hemoCD as a CO antidote for clinical use.

The growing demand for lithium-ion batteries requires improved performance and productivity. The formation of electronic conduction paths by carbon nanotubes (CNTs) is an important factor influencing electrode performance. However, only a few methods have been reported to allow direct and quantitative evaluation of CNT dispersion. Conventional ion milling for cross-sectional preparation exposes only CNTs in the interstices of active materials, limiting accurate assessment. In this study, we applied a fracturing method to prepare electrode cross sections, thereby exposing more CNTs in the observation area and enabling clear visualization of CNT networks. Furthermore, low-accelerating-voltage SEM enhanced the contrast between binders and CNTs, facilitating their separation and enabling quantitative evaluation of CNT linear density when combined with machine-learning-based image analysis. This study demonstrates a direct and quantitative method for assessing CNT distribution in lithium-ion battery electrodes.

Active matter often exhibits ordered collective motion, such as in bacterial colonies or swarms of fish and birds. Understanding the mechanisms underlying the complicated collective behaviors is significant to develop innovative chemical systems. We discovered that Pt catalytic particles with simpler structures exhibit a unique collective motion, that is, repetitive cluster formation and disintegration in an aqueous ethanol solution. In this study, the collective behavior of Pt particles is demonstrated in mixtures containing inert particles. Two distinct types of cluster formation were observed by varying the mixing ratio of the Pt and Au particles: Pt/Au mosaic-like clusters and Pt/Au core–shell clusters. In contrast, no Pt/silica cluster formation was observed in the silica particles mixed with Pt particles. In the Pt/Au core–shell clusters observed in this study, the thickness of the Au particle shell could be controlled by adjusting the concentration of the Au particle. This finding suggests that the spatial separation of Pt and Au particles can be realized under controlled conditions.