In this study, to clarify the mechanism of the permeation and collection through a filter, a direct numerical simulation model for multi-phase flows was newly developed. We extend this model to apply air filter and coalescer. To represent a realistic microporous structure inside the filters during simulation, a numerical method that coordinates the filter structure obtained by X-ray CT imaging with computational fluid dynamics is developed. The predictions of filter pressure drop from our numerical method were quantitatively in good agreement with the experimental measurements and the empirical equations previously reported. Finally, we demonstrated that the present method can be easily extended to multiphase flow simulations.

Microstructure of the air-electrode for metal air battery was controlled by dispersion control between catalyst and carbon particles in the ink. The dispersion of each particles was controlled by the electrostatic repulsion force in the ink. The surface area of catalyst particles in the air-electrode was improved by the hetero coagulation between catalyst and carbon particles in the case of nano-particle catalyst. On the other hand, the relatively large surface area of catalyst in the air-electrode was attained at the well dispersed condition in the case of the catalyst particle with sub-micron diameter. As a result, the catalytic activity for oxygen evolution reaction increased with increasing the surface area of catalyst in the air-electrode.

A core–shell anode consisting of nickel–gadolinium-doped-ceria (Ni–GDC) nanocubes was directly fabricated by a chemical process in a solution containing a nickel source and GDC nanocubes covered with highly reactive {001} facets. The cermet anode effectively generated a Ni metal framework even at 500°C with the growth of the Ni spheres. Anode fabrication at such a low temperature without any sintering could insert a finely nanostructured layer close to the interface between the electrolyte and the anode. The maximum power density of the attractive anode was 97 mW·cm^–2, which is higher than that of a conventional NiO–GDC anode prepared by an aerosol process at 55 mW·cm^–2 and 600°C, followed by sintering at 1300°C. Furthermore, the macro- and microstructure of the Ni–GDC-nanocube anode were preserved before and after the power-generation test at 700°C. Especially, the reactive {001} facets were stabled even after generation test, which served to reduce the activation energy for fuel oxidation successfully.

This research demonstrated a simple, facile means for the production of monodisperse fine metal particles with high levels of crystallinity and purity using a rapid spray heating process. Fine particles of colloidal Ag (geometric mean diameter d_p = 1.01 μm, geometric standard deviation σ_g = 1.22 and crystal size d_c = 22 nm) prepared by a liquid phase method were used as a test material to evaluate the proposed technique, and the effects of drying temperature (200–900°C) on particle characteristics were investigated in detail. The particles obtained after spray heating at 500°C exhibited high crystallinity (d_c = 40 nm) and high purity while keeping their initial morphology and size distribution (d_p = 0.92 μm, σ_g = 1.24). The volume resistivity of the fine Ag particles after spray heating was 3.6 × 10^–5 Ω·cm, which was considerably lower than that of fine Ag particles before spray heating (6.4 × 10^–3 Ω·cm) by a factor of 180. The simple method proposed in this paper has the potential to produce high-quality fine particles of various metals suitable for real-world applications.

The mechanochemical polymerization method uses active center of the powder fracture surface to produce by grinding operation, and it is method to approximately completely carry out a polymer coating in crushed inorganic surface. We focused the attention on the waste glass of the car which had low recycling percentage achievement, and we thought about reusing this as silica filler by mechanochemical polymerization processing now. We found what a polymer generated in the water recently by carrying out mechanochemical polymerization reaction with the high ability mill for grinding such as the planetary mill. Therefore, a preparation of the polymer coating silica filler by the wet grinding using the water was investigated. As a result, we succeeded in a preparation of the silica filler that surface of the waste glass was coated with a polymer. Hence progress of the mechanochemical polymerization reaction was confirmed by grinding of the waste glass in the water. In addition, the particle diameter of the product was around 200 nm without depending on the particle diameter of raw materials.

Emulsions stabilized by adsorbing fine particles are called Pickering emulsions, and are attracting attention as a technique for stabilizing emulsions without using a surfactant. The stabilization of the oil-water interface by the fine particles should follow a change in the interfacial tension, but it is not systematically understood. The purpose of this study is to clarify the effect of particle adsorption on the interfacial tension at the oil-water interface. Monodisperse and spherical particles were used to make it easier to analyze the effects of the particles. In the measurement of the interfacial tension, a quasi-elastic light scattering method was employed to avoid the effect of the probe contacting the interface. The interfacial tension at the decane/water interface was measured as a function of the number of adsorbed particles; the interfacial tension decreased with the amount of dispersed particles. The decrease in interfacial tension was much larger than the stabilization free energy due to the adsorption of the particles, or the repulsive interaction between the adsorbed particles, suggesting that the decrease is due to synergetic effects of structural change of the interface.

Using red blood cells (RBCs), we have fabricated functional soft particles, which exhibit not only several kinds of shapes but also biologically functional sugar chains of ABO blood group on the RBC membrane even after chemical fixation. It was found that chemical fixation of RBCs with paraformaldehyde significantly reduces the adsorption amount of bovine serum albumin on an RBC, but hardly affects that of lectins (i.e., proteins that recognize blood type sugar chains).

The surface of the particles was identified using the Hansen solubility parameter (HSP). From a comparison of the HSP of the unmodified and modified silica, an NH₂ group is suitable for entrapment of the silica by cellulose acetate as the polymer. However, with an increase in number of the silica particles, entrapment of the silica in the polymer was prevented. Control of the phase separation rate by the lowering temperature leaded to entrapment of silica particles in the polymer network. The proposed technique is effective not only for spherical oxide particles, but also for non-oxides, various shapes and structures. Depending on particle characteristics, functional films and bulk materials for thermal insulation, light diffusion, and electro conductivity can be obtained.

Recently, many insoluble drugs were produced with progressing the search method of novel drug, such as the combinatorial chemistry and high through-put screening studies. Therefore, it is important to develop a technic to enhance the bioavailability of insoluble drugs. In this study, we prepared the nanocrystal based on crystal polymorph of cilostazol (CLZ), and found that the crystal polymorph affected the solubility, stability and bioavailability in the CLZ nanocrystal. In addition, we designed the oral formulation containing CLZ nanocrystal (CLZ/R-NPs tablet) by the combination of recrystallization and ball milling. The areas under the concentration-time curve (AUC) in rats orally administered CLZ/R-NPs tablet were significantly higher than that in OD tablets with CLZ powder (CLZ/R-MPs tablet), and the AUC levels of CLZ/R-NPs tablet was approximately 2-fold of CLZ/R-MPs tablet. In addition, the oral administration of CLZ/R-NPs tablets attenuated the neurological deficits caused by ischemic stroke in a cerebral ischemia/reperfusion-induced injury model (MCAO/reperfusion mice). It is possible that the oral formulation based on CLZ nanocrystal will be useful for the treatment of patients with ischemic stroke and that these findings will provide significant information that can be used to improve the drug with low bioavailability.

The human society has abundant and various environmental vibrations caused by working factories and running vehicles. Most of the vibrations are lost as thermal energy and are regarded as pollutions in our life. Recently, the technologies utilizing these environmental vibrations is developing.

When a powder layer undergoes vertical vibration, the unique characteristic patterns appear depending on the frequency and amplitude of the vibration. Regarding theses pattern formations, the behaviors and the properties of the pattern formations have been investigated to understand the mechanisms. On the other hand, motion of objects on vibrating powder layer that may be applied for their transport remains less studied.

In our research, objects with various structures on the powder layer with various particle size under the vertical vibration were observed. Moreover, the kinetic mechanism of the motion of the objects were considered from the relations between the behaviors of the powder and the objects.

Amorphous nanoparticle composed of poorly water soluble glibenclamide (GLB) and stabilizer hypromellose (HPMC) was prepared by two antisolvent methods. In method A, DMSO solution containing GLB was poured into water containing HPMC to prepare nano-A suspension. In method B, a DMSO solution containing both GLB and HPMC was poured into water to obtain nano-B suspension. The morphology of nano-A and nano-B was spherical hollow and deformed non-hollow particles, respectively. The GLB amorphous was more stable in nano-A than in nano-B during heating process, because GLB and HPMC in nano-B was more miscible than in nano-A. The stability of the amorphous GLB in nanoparticles was strongly affected by GLB/HPMC miscibility, depending on their methods of preparation.

Nanomaterials, including carbon nanotubes (CNTs), are coated by proteins in early stages of their uptake into biological systems. The protein layers around the nanomaterial surfaces are called protein corona, which determines the fate pathways and biological impacts of the nanomaterials. However, little is known about interactions of proteins with the nanomaterials during protein corona formation. In this work, we discovered that CNTs form thick and dense protein layers on their surfaces and induce oxidative stress on the proteins. The proposed protein oxidation mechanism will advance the fundamental understanding of the biological safety and toxicity of nanomaterials.

By calculating trajectories of aerosol particles by Langevin dynamics method, in which random motion of aerosol particles are represented by pseudo random number, coagulation coefficient of aerosol was calculated. Both interval times between collision of one particle with other particles, and concentration distribution of particles were calculated in MTBC method: it was utilized to investigate the coagulation coefficient in transition regime. Coagulation coefficient obtained by the MTBC method corrected by concentration of particle at infinity are smaller than that obtained by flux matching method by Fuchs (1964). This suggests that the assumption made in the flux matching method does not hold completely. Then, in order to develop numerical model of change in particle size distribution by coagulation, GPGPU was employed to calculate the coagulation coefficient by parallel computing of motion of large number of particles.

We have been developing a new coating method for structural color film caused by colloidal crystal. Three-dimensional objects treated with hydrophilic surfaces were immersed in polystyrene colloidal suspension. Liquid film of colloidal suspension wetted for the objects’ surface and furthermore the liquid surface was covered with a silicone oil liquid. The objects pull out from the colloidal suspension at 60 μm/min rate and coated with colloidal crystal film showing with structural color. The color from blue to red has controlled with the size of the colloidal particle, interspacing of the particles and the refractive index of colloidal crystal film. In addition, our new coating method enables us to coat of high-quality colloidal crystal film on a three-dimensional surface having irregularities or curvature. At the lab level, a polystyrene suspension equivalent to 80 L was prepared and an A3 scale size coating was demonstrated. From a different viewpoint, the suspension can be recycled and a colloidal crystal can be formed at around room temperature. We believe this coating method environmental friendly process with low energy consumption. However, since the deposition rate of the colloidal crystal thin film is very slow, a practical coating process needs improvement.

In this study, the magnetic orientation behavior of K₂NiF₄ type layered Ni-based perovskite compound Ln₂NiO₄ (Ln = La, Pr and Nd), which has attracted much attention as a cathode material for low-temperature solid oxide fuel cells, was investigated. The final goal of this study is to develop effective process to fabricate oriented cathodes on electrolytes in a low magnetic field. According to our previous study, La₂NiO₄ can be oriented in a strong magnetic field of 12 T, but no orientation is made under a low magnetic field of 1 T or less. On the other hand, as a result of this study, it was found that, for example, PrNdNiO₄ shown below was oriented in a low magnetic field of 0.9 T, leading to materials design for high performance electrode particles. In addition, the easy magnetization axis for PrNdNiO₄ was the c-axis. Higher conductivity was obtained on the ab plane in conductivity measurements. From these results, it is shown that high performance oriented electrode of PrNdNiO₄ can be fabricated by applying a low magnetic field parallel to the surface of electrolyte.

In the present study, we have studied the impact on a granular bed by a hydrogel sphere. The impact of an object will lead to the formation of a crater. The diameter of the crater is proportional to the 1/4 power of the kinetic energy of the object for low speed impact of a solid sphere. For a liquid drop impact cratering, some scaling factors (from 1/6 to 2/5) have been reported due to the complexity of a liquid drop impact phenomenon such as deformation, splashing, and penetrating granular bed. Considering only the effect of the deformation on the scaling relation, we investigated the impact cratering of a hydrogel sphere which deforms without splashing and penetrating. For spheres with high Young’s modulus, the relation of the 1/4 power law, which is reported for a solid sphere impact cratering, is observed. On the other hand, the power is smaller than 1/4 for the impact of the sphere with small Young’s modulus.

Filtration is widely used to separate or concentrate deformable particulate suspensions in various industrial processes. In the filtration process, particulate fouling, which causes a decrease in permeation flux, is generally inevitable. To design the filtration process for effective suppression of fouling, we must understand the fouling phenomena essentially. A numerical simulation is an effective approach to understand the fouling mechanism of deformable materials. In this study, a novel simulation model was developed, which enables to independently evaluate various factors influencing on membrane fouling and visualize the particle motion. The simulation of the cross-flow filtration of a deformable particle was conducted to investigate the effect of the particle deformability on membrane fouling. The simulation results demonstrate that the present model can reproduce the dynamics of deformable particle in the filtration process.

Liesegang phenomenon has been extensively studied experimentally and theoretically in the field of nonlinear science. However, there are few studies for its applications due to the high nonlinearity. The particles produced with the Liesegang phenomenon have been limited to microparticles of sparingly soluble salt for many years. In this study, in anticipation of more engineering application of this phenomenon, metal nanoparticles are synthesized by diffusing metal ions into a gel containing a reductant. At that time, we investigate the influence of diffusion conditions on particle formation. As a result, we found that the size of resultant particles depends on the gel position. Furthermore, we construct mathematical model expressing ion diffusion and particle growth based on Ostwald ripening to discuss the particle formation mechanism.

First-principles calculations were conducted to study the possibility of the formation of SnTiO₃. Nanocluster models were used, and BaTiO₃ and SnTiO₃ were studied. SnTiO₃ was stabilized with Sn rich surface similar to the BaTiO₃. Also, SnTiO₃ has smaller surface energy than that of BaTiO₃, suggesting the possibility of the formation of nanoparticles of SnTiO3 and stabilization of the unstable structure with nanometer-size. As a result of nanoparticle synthesis of BaTiO₃, Ba deficient structure was elucidated. Under the condition, the synthesis of Sn-Ti composite oxide was studied.

Ceramic-based fiber reinforced composites based on silicon carbide (SiC) and alumina (Al₂O₃) have been expected to be applied in the aerospace, environment and energy fields as next-generation highly reliable heat-resistant materials. The fiber/matrix interface in ceramic-based fiber reinforced composites plays an important role to develop excellent mechanical properties, and it is important to form optimal interface layers in the composites and to control the interface. The aim of this study is to develop the novel formation process of nano-scale coating layer (interfacial layer) with the thickness of several tens to several hundreds of nanometers on the surface of ceramic fibers (micro-scale substrate) by electrophoretic deposition (EPD) method, and the formation process of carbon coating layer and hexagonal boron nitride coating layer on the conductive and low-conductive SiC fibers by EPD was studied.

The present study focused on the self-assembly of porous metal-organic framework (MOF) particles into spherical superstructures and characterization of structural and adsorption properties of fabricated superstructures, aiming at practical applications of MOFs in separation processes. Self-assembly was conducted by mixing MOF particles dispersed in MeOH-water mixture with fluorinated oil to make suspension droplets, followed by the drying. Spherical superstructures formed at a MeOH-water mixture volume ratio of 1 : 1 possibly because both the droplet and dispersion stabilities are enhanced. Porosity of superstructures was approximately 0.3, indicating that the structure is close to the close-packed one. Adsorbed amount in superstructures was less than in MOF power, although the adsorption rate is larger for a superstructure-packed bed than powder-packed one because gaps between superstructures act as meso/macro pores to promote mass transfer.

Perovskite nanocrystals (PeNCs) have superior optical properties like narrow half width and a high quantum yield and are expected as a photonic source for a wide color gamut display. However, precise controlling of the PeNC sizes which is capable to demonstrate the PL peaks in wide range has not been developed. From the above background, we have been proposing a down-sizing protocol preparing for the PeNCs using Ostwald ripening, and we elucidate the PL behavior from the down-sized PeNCs in this report.