Volcanic glass microballoons (so-called Shirasu balloons) are produced via the expansion of hot volcano ash sand. This work assessed the application of a biocompatible hydroxyapatite (HAp) coating to this material, which both floats in most solvents and has extremely thin outer shells. A two-step process consisting of homogeneous precipitation followed by conversion of the crystal phase using static liquid immersion was found to be effective for this purpose. A uniform HAp coating was obtained by converting the initial calcium phosphate layer to HAp by immersing the microballoons in an optimized solution under static conditions.

For the purpose of developing an actuator for wearable-assistive devices, we have devised and produced a weft yarn-type shape memory alloy (SMA) actuator using the resistance feedback control method. This actuator consists of a polyethylene terephthalate (PET) plate and SMA wire woven into the weft pattern. Since the PET plate and SMA wire are constrained in the lateral direction, this actuator can do the bending operation by the actuation of the SMA wire. In this research, the effects of constraint conditions of the PET plate and SMA wire (i.e. the distance between PET plate and SMA wire (D)), and the number of constraining points (N) were investigated with respect to the bending operating characteristics (bending deflection and operating velocity) of the weft yarn-type SMA actuator. The bending deflection of the actuator was seen to increases with the increase of N. However, the bending deflection of the actuator was seen to decreases with the increase of N beyond the maximum value. The variation of deflection is caused by the variation of frictional force due to the variation of N. Furthermore, the bending deflection of the actuator and operating velocity decrease as D increases. This tendency is caused by the increase of the curvature radius of actuator with the increase of D.

  Si nanoparticles were synthesised by the Mg reduction process of SiO₂ powder extracted from rice husks and their optical properties and crystal structures were studied. Room temperature luminescence was observed from the Si nanoparticles formed by Mg reduction of the SiO₂ powder with reduction temperatures of 550 ℃ and 700 ℃. Transmission electron microscopy observation of the SiO₂ powder extracted from rice husks revealed that an aggregate consisting of numerous SiO₂ nanoparticles was formed. The formation of crystalline Si nanoparticles and the aggregate by Mg reduction of the SiO₂ nanoparticles was confirmed. Mg reduction of SiO₂ powder extracted from rice husks is an effective method for the simple and large-scale preparation of luminescent Si nanocrystals by using the nano-bio structure of live rice plants.

The relationship between the potassium content in rice hull charcoal and strontium ion adsorption was investigated. Potassium elution treatment was performed on rice hull charcoal, wherein the rice hull charcoal was stirred with distilled water. The pore distribution and specific surface area of the processed rice hull charcoal were measured. Significant change was not observed in the mesopore volumes of rice hull charcoal subjected to elution treatment for 1 h. The specific surface area increased as the elution time became longer. Based on the result of the pore distribution, it was assumed that the macropores increased. Potassium was eluted at 56.0 mg/L from rice hull charcoal subjected to elution treatment for 3 h. This eluted approximately 83% of potassium content. In the strontium ion adsorption experiment, the adsorption amount of the eluted rice hull charcoal was approximately 40% lower than that of untreated rice hull charcoal. High correlation was observed between the potassium content and the strontium ion adsorption amount. Thus, this paper confirmed that it is possible to show a higher adsorption ability by using rice hull charcoal with high potassium content.

  Codimerization of ethylene with styrene takes place in the presence of the RuCl₂(MeCN)₂(cod)/MAO catalyst at room temperature to yield 3-phenyl-1-butene accompanied by formation of 1,3-diphenyl-1-butene as a by-product. The reaction with molar ratio of [styrene]/[Ru]/[Al] = 10000/1/300 resulted in 83% conversion of styrene and 93% selectivity of 3-phenyl-1-butene after 2 h. RuCl₂(MeCN)₂(cod)/Et₂AlCl also catalyzes the hydrovinylation of styrene, and the reaction produces 3-phenyl-1-butene and 1,3-diphenyl-1-butene in 71:29 ratio after 30 min. ¹H NMR spectroscopy of the reaction mixture for a longer period revealed that 1,3-diphenyl-1-butene, the byproduct, was converted to 3-phenyl-1-butene, probably via Ru-catalyzed metathesis reaction of 1,3-diphenyl-1-butene with ethylene. RuCl₂(MeCN)₂(cod)/MAO also promotes hydrovinylation of norbornene and 1-phenyl-1,3-butadiene to give exo-2-vinylnorbornane and (E)-5-phenyl-3-methyl-1,4-pentadiene, respectively.

Three-dimensional (3D) X-ray topography was used to characterize diamond anvil crystals before and after application of ultra-high pressure at 50, 70 and 99.4 GPa. The diffraction planes examined and the wavelength of the monochromatic X-rays were (004), (333), {224}, {440} and 0.0521 nm, respectively. Images of lattice defects in the diamond crystals were reconstructed by stacking approximately 500 X-ray limited projection topographs using the image processing software Image J. The 3D structures and nature of the lattice defects were identified from the reconstructed topographs. A pyramidal shape of four parts of stacking faults was identified using the visibility or invisibility of defect images with each diffraction plane. No significant changes of the lattice defects in the diamond crystals were observed under pressurization at 70 GPa. However, one of the anvil crystals shaped from the same rough crystal was broken into pieces at 99.4 GPa. The fracture stress is very low value rather than the calculated one based on (111) [110] slip system mechanism. In the broken crystal, the center line of plurality of the pyramidal shape of stacking faults differed in the location from the culet area. The breaking of diamond crystal was dependent on the distribution of plane defects in the crystal.

  We examine the formation of long-period stacking ordered (LPSO) structure for Mg-RE-Zn (RE = La, Tb, Dy, Ho, Er) ternary alloys based on the short-range order (SRO) tendency of energetically competitive disordered phases. While we see that SRO does not show effective correlation with atomic radius, we find that anisotropic SRO tendencies for structures with stacking faults cannot be simply interpreted by arithmetic average of SRO for constituent fcc and hcp stackings, indicating that the SRO should be significantly affected by periodically-introduced stacking faults. We also find that SRO for neighboring RE-Zn pair, which should have positive sign to form specific L1₂ type cluster found in LPSO, is strongly affected by the distance between stacking faults: e.g., five atomic layer distance does not prefer in-plane RE-Zn pair, while seven atomic layer distance prefer both in- and inter-plane RE-Zn pair. These facts strongly indicate that ordering tendency for the Mg-RE-Zn alloy is significantly dominated by the stacking faults as well as their periodicity, precursor to form L1₂ cluster in LPSO structure.

We previously reported that 2-aminotryptanthrin (T2NH₂) and 2-(N,N-dimethylamino)tryptanthrin (T2NMe₂) possess excellent photophysical properties such as wide-wavelength absorption and emission in the visible region and a high fluorescence quantum yield. These compounds also exhibit large positive fluorescent solvatochromism. In this study, the new derivative 2-(N,N-diphenylamino)tryptanthrin (T2NPh₂) is synthesized, and its photophysical properties are investigated. In contrast to T2NH₂ and T2NMe₂, T2NPhe₂ shows weak fluorescence only in nonpolar toluene and 1,4-dioxane among the 13 solvents of different polarity tested, which is considered to be due to thermal deactivation resulting from the promotion of internal conversion by the rotation of the phenyl groups. Although T2NPhe₂ is nonfluorescent in tetrahydrofuran (THF), fluorescence is observed in water/THF solutions with more than 80 vol% water content as a result of aggregation-induced emission.

The adsorption and separation behaviors of CO₂ and CH₄ gases on nanoporous carbon (NPC) fabricated from rice husk were investigated for possible applications in industrial carbon dioxide capture and storage (CCS). The NPC was fabricated from carbonized rice husks by alkaline activation with potassium hydrate (KOH), and it had pore sizes of 1.0, 1.2, and 1.7 nm and a specific surface area of 1520–3379 m²/g. The adsorption and separation behaviors of CO₂ and CH₄ on it were measured by gas chromatography (GC). The adsorption and separation behaviors on NPCs was depended on it’s pore structures. The single-gas storage capacities were 3.7–19.3 mmol/g for CO₂ and 3.8–9.5 mmol/g for CH₄ at temperatures of 278–333 K. Furthermore, the separation coefficient for selective adsorption of CH₄ from a mixture of CO₂ and CH₄ gases was measured to range from 1.36–2.38. These results indicate that this NPC produced using agricultural sustainable material is a good candidate for industrial CCS techniques.