The characteristics of high-temperature oxide fuel cells and high-temperature steam electrolysis cells under millimeter-wave irradiation were evaluated and compared with those evaluated under conventional electric furnace heating. A reversible high-temperature electrochemical cell was fabricated using alumina-dispersed zirconia as the electrolyte, lanthanum strontium manganate as the air electrode, and nickel-ziconia based cermet as the fuel one. The power generation characteristic of the fuel cell under millimeter wave irradiation was 32% higher than that of a conventional electric furnace temperature heating, and the steam electrolysis efficiency was also 120% higher under millimeter-wave irradiation than that under conventional one. Impedance measurements using an air electrode-electrolyte half-cell showed that the millimeter wave irradiation facilitated the dissociation of oxygen molecule and/or diffusion of oxygen atoms on the surface of the air electrode as well as the oxide ion conduction in the electrolyte.

Long-lasting phosphors, SrAl₂O₄: Eu, Dy and CaAl₂O₄: Eu, Nd, have been prepared by a short process using the spark plasma sintering method. The raw oxide powders were mixed for 5 min using a high-energy mill. Subsequently, solid-state reaction and sintering were simultaneously performed for approximately 20 min using a spark plasma sintering apparatus. The sintering temperatures were set to 1150–1500°C for SrAl₂O₄: Eu, Dy and 1100–1400°C for CaAl₂O₄: Eu, Nd. The X-ray diffraction patterns showed that a sintering temperature of 1400°C or higher was required for single-phase synthesis of SrAl₂O₄: Eu, Dy, while a sintering temperature of 1200°C was suitable for synthesis of CaAl₂O₄: Eu, Nd. The sintered SrAl₂O₄: Eu, Dy and CaAl₂O₄: Eu, Nd phosphors exhibited bright green and blue emission by ultraviolet irradiation, respectively, and they showed afterglow properties. In particular, SrAl₂O₄: Eu, Dy prepared at 1500°C and CaAl₂O₄: Eu, Nd prepared at 1200°C showed good performance in terms of both the initial emission intensity and afterglow properties. Thus, sintered long-lasting SrAl₂O₄: Eu, Dy and CaAl₂O₄: Eu, Nd phosphors can be prepared by a short process using spark plasma sintering if the sintering temperatures are properly selected.

Barium ferrite particles were synthesized from acicular α-Fe₂O₃ particles grown in the c-axis direction. The synthesis was carried out by the flux method, in which acicular α-Fe₂O₃ particles reacted with BaCO₃ in NaCO₃ flux. The acicular-shaped BaFe₁₂O₁₉ particles grown in the c-axis direction were obtained. The acicular shape consisted of aggregates of plate-like particles stacked along the c-axis. The platelet-shaped BaFe₁₂O₁₉ particles prepared from spherical α-Fe₂O₃ under the same synthesis conditions exhibited a smaller coercivity than the acicular BaFe₁₂O₁₉ particles synthesized in this study. Therefore, it can be inferred that the shape anisotropy has an effect on the magnetic properties of the acicular particles.