Monolayer films composed of ordered particle arrays exhibit unique optical properties, which lead to various potential applications like sensors and antireflective coatings. In this study, we investigated particle deposition processes by using a drag coating technique based on convective self-assembly. Unlike micron-sized particles, 300-nm particles formed submonolayers instead of monolayers. Hence, we modified the technique and demonstrated that reversed dragging, introduction of a film blade, and periodic change in deposition speed dramatically improved the particle deposition process to cover the entire substrate surface uniformly with a monolayer of ordered particle arrays. Furthermore, our modified drag coating process produced monolayers of particles with different sizes of 570, 120, 45, and 27 nm. Thus, our technique is simple and versatile, and is applicable to a wide particle size ranging from microns to tens of nanometers.

Wet granules are applied for various fields due to their high workability and cost performance. However, it is difficult to observe the water distribution of wet granules directly because of the extremely small amount of water. In this study, the water distribution of wet granules was investigated by confocal laser microscope and quantitatively analyzed by using autocorrelation function. Furthermore, the correlation length of wet granules estimated from autocorrelation function was compared with their shear properties. Consequently, it was elucidated that angle of internal friction of wet granules decreased with increasing water volume between particles. These results indicated that water of wet granules works as drag reduction agent under shear conditions.

A chemical solution deposition method (CSD method) is suitable for preparing fine particles by low temperature annealing. Here the method was utilized for preparing 12CaO·7Al₂O₃ (C12A7) fine particles, which was composed of nanosize cage structure clathrating oxygen radicals (O⁻) and had a high potential for application of strong oxidizing catalysis. The particles prepared by CSD method showed higher specific surface area than those prepared by solid state reaction even though after subsequent ball milling. Another method, solution plasma processing, of preparation of C12A7 particles from precursor solution was also introduced. The products obtained by the solution plasma processing were fine particles and they included new phase of C12A7 with ca. 5% large lattice parameter.

The multistage adsorption test was carried out to remove lead from a closed mine wastewater using moss protonemata. The test was operated at a flow rate of 260 mL h⁻¹, at a space velocity of 0.5. The initial concentration of lead was 1.9 mg L⁻¹, the target concentrations of lead in the final outlet solutions were set against the Japanese uniform national effluent standards. The results showed that four stages are needed to obtain the targeted limit of 0.1 mg L⁻¹ for lead set by the effluent standards, and the estimated bed volume was twenty. The maximum adsorption capacity was about 3% in its dry weight. The trial calculation of real scale was simply made. Hydraulic conductivity was measured, and the value after the test was slightly higher than that before the test. It means to be sufficient for the solid-liquid separation process in industry.