Octacalcium phosphate (OCP) has a layered structure and can accommodate various carboxylate ions, resulting in different interplanar spacings of its (100) plane. An example of the continuous expansion of the interplanar spacing of OCP has been demonstrated using mercaptosuccinic acid (MSA). The mercapto groups of carboxylic acid likely exhibit important roles in the continuous interplanar spacing expansion of the OCP with incorporated carboxylate ions. However, the origin of the continuous interplanar spacing expansion of the OCP incorporating carboxylate ions with mercapto groups is still unclear. In this study, we investigated the incorporation of meso-2,3-dimercaptosuccinic acid (MDSA) with two mercapto groups into the OCP interlayers and investigated whether continuous expansion of the interplanar spacing occurred. We synthesized OCP in aqueous solutions of various MDSA concentrations and characterized it by X-ray diffraction. OCP was formed at low MDSA concentrations, whereas at higher MDSA concentrations, MDSA inhibited the formation of OCP. The interplanar spacing of the OCP formed at low MDSA concentrations increased with increasing MDSA concentration. In other words, MDSA was incorporated into the OCP and caused its continuous interplanar spacing expansion. Hence, we successfully obtained compelling evidence indicating the importance of mercapto groups of carboxylic acid on the continuous interplanar spacing expansion of OCP. Our findings will contribute to the advancements in the chemistry of OCPs with incorporated carboxylate ions.

Chemical modification of metal alkoxides is crucial for controlling hydrolysis and polycondensation, as variations in electronegativity can cause uneven chelation and polymerization, leading to solution uniformity issues, molecular segregation, and undesired phases. This study highlights the importance of precise modulation to prevent phases like tetragonal LLZO or pyrochlore, preserving the desired cubic garnet structure of Al-doped Li₇La₃Zr₂O₁₂ (LLZAO) at lower temperatures. Synthesis of Al-substituted LLZAO fine powders via the metal alkoxide method aims for molecular-level homogeneity. Controlling rapid hydrolysis of both Zr and Al alkoxides is crucial for stabilizing monophasic cubic LLZAO and achieving lower calcination temperatures of 750 °C within 3 h, resulting in a sintered pellet with significant bulk ionic conductivity of 1.14 × 10⁻⁴ S cm⁻¹ at room temperature, underscoring the potential of chemically modified LLZAO as an efficient solid electrolyte for next-generation lithium-ion batteries.

We report a new sodium-ion conducting fluorides, NaTaF₆, Na₂TaF₇, and Na₃TaF₈ as the possible candidates for a solid electrolyte in composite positive electrode for all-solid-state sodium batteries with high operating voltage. The mechanochemically prepared Na₂TaF₇ sample shows the ionic conductivity of 1.1 × 10⁻⁶ S cm⁻¹ at 100 °C and the activation energy of 0.67 eV. The Na₂TaF₇ sample has the electrochemically stability between 1.6 and 4.2 V vs. Na₂Sn. This report pioneeringly develops the sodium-ion conducting fluorides with high electrochemical stability for all-solid-state batteries.

Fining of soda-lime glass by Na₂SO₄ in a water vapor atmosphere was evaluated via direct observation and viscosity measurement of the melt. Direct observation of the melt was performed using the hot-thermocouple method, which can capture the behavior of bubbles in the melt in a water vapor atmosphere. When the moisture concentration in the atmosphere was high, a reduction in the bubble generation temperature and an increase in the number of generated bubbles were observed. In addition, the viscosity of the sample melt was measured using the rotation cylinder method. The viscosity at a water vapor partial pressure of 98 kPa was 14–16 % lower than that at 2 kPa at 1400–1600 °C. To evaluate fining, the bubble floating velocity was calculated using direct observation of the melt and the viscosity measurement results. At 1400 °C, the bubble emergence rate at P_H2O = 98 kPa was approximately six times faster than that at P_H2O = 2 kPa. These findings suggest that an increase in the moisture concentration in the atmosphere reduces the temperature at which bubbles are generated by Na₂SO₄, thereby promoting fining at a lower level than in air.

In this study, Mg²⁺-containing hydroxyapatite (MgHAp) and chitosan (CS) composite particles (MgHAp/CS) with different CS contents were synthesized, and the relationship between CS content and adsorption of negatively charged protein (bovine serum albumin), was investigated. The CS content in the particles ranged from 18–42 wt %. Specific surface area results indicated that higher CS content could lead to CS aggregation on and between MgHAp particles. The saturation adsorption of bovine serum albumin on the MgHAp/CS particles ranged from 1.48 to 3.64 mg/m². The particles with 42 wt % CS content exhibited the highest saturation adsorption amount among the particles. Additionally, protein adsorption tended to increase with higher CS content, probably because more positively charged CS (–NH₃⁺) on the particle surface facilitates electrostatic interactions with negatively charged proteins. This suggests that positively charged CS in the particles can regulate the amount of protein adsorbed.

We investigated the effects of adding classified small-sized AlN whiskers during the fabrication of low-temperature-sintered AlN ceramics on the densification and mechanical properties. The samples without the whiskers had low mechanical strength due to low-temperature sintering, but the addition of the whiskers increased the mechanical strength. Adding unclassified whiskers decreased the relative density and created voids among the particles. In contrast, the addition of classified small-sized whiskers resulted in a higher relative density and a clear increase in mechanical strength.

Y₃Al₅O₁₂:Ce (YAG:Ce) is used as a yellow phosphor in combination with blue light emitting diodes (LEDs) in white LEDs. YAG crystals with a super-high content of Ce (SHYAGCe) and anomalous redshifts can be prepared using a polymerized complex method by employing low-temperature annealing prior to sintering. Low-temperature annealing at approximately 650–750 °C is essential for doping a high content of Ce in YAG. However, the effect of the sintering temperature on the formation of the crystal structure has not been investigated. In this paper, we study the effect of the sintering temperature on the crystal structure and luminescence property. A single phase of YAG crystals is formed only when sintering is performed at 1030–1080 °C. This implies that the sintering temperature affects the formation of SHYAGCe.