To simulate the atmospheric corrosion of aluminum materials, artificial aluminum rust particles were synthesized by aging the solution containing AlCl₃, Al(NO₃)₃ and Al₂(SO₄)₃. Then, the molar ratio OH⁻ ⁄ 3Al³⁺ of the solution was adjusted to 0–1.5. At OH⁻ ⁄ 3Al³⁺ = 0, no precipitates were obtained from any solutions. At OH⁻ ⁄ 3Al³⁺ = 0.25–0.75, NaAl₃(SO₄)₂(OH)₆ was mainly formed in Al(NO₃)₃-Al₂(SO₄)₃, Al₂(SO₄)₃-AlCl₃ and AlCl₃-Al(NO₃)₃-Al₂(SO₄)₃ systems, while the particles were not yielded in AlCl₃-Al(NO₃)₃ system. The γ-AlOOH particles were generated from each solution at OH⁻ ⁄ 3Al³⁺ = 1.0. In case of OH⁻ ⁄ 3Al³⁺ = 1.5, increasing amount of SO₄²⁻ turned the major product following as Al(OH)₃ → γ-AlOOH → no precipitate. These results indicate that formation and structure of aluminum rust particles depend on the anions and the effect is in the order of SO₄²⁻ > Cl⁻ ≈ NO₃⁻. Consequently, SOx gas remarkably affects the rust formation in atmospheric corrosion of aluminum materials.

Soap-free emulsion polymerizations were carried out in a packed-bed reactor using glass beads with various surface roughness to improve the yield of polymer nanoparticles. The rough surfaces of glass beads prepared by a ball-milling suppressed the convection flows in the reactor, improving the residence time of the raw materials for the polymerization to promote the polymer yield, which was investigated by computational fluid dynamics. Furthermore, the reduction of the collision frequencies between particles due to the flow suppression prevented their growth, resulting in particle sizes below 100 nm without using surfactant.

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.