In the molten hydroxide method using potassium hydroxide as a flux, Nd/Ba substitution was suppressed by reducing the oxygen concentration in the solution, enabling low-temperature synthesis of Nd123 epitaxial films with high T_c. When using several Cu raw materials with different oxygen contents, employing metal Cu with lowest oxygen content resulted in Nd123 films with higher T_c. However, compared to conventional bulk Nd123 without Nd/Ba substitution, the T_c was still lower. Using metal Cu as the Cu raw material and employing a solution with an even lower oxygen concentration by bubbling with N₂ gas, an Nd123 film with a T_c of 93 K, comparable to the bulk T_c value, was obtained at a low synthesis temperature of 550ºC. Furthermore, the reduction in synthesis temperature and deposition time also minimized elemental diffusion from the substrate and improved film homogeneity.

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This paper proposes the "Parallel cell cluster method" as a PV module-level solution to the problem of output power decrease caused by partial shading of the PV array in a PV power generation system. This method is new method previously proposed by the authors to reduce hot spot heating caused by crystal defects in PV cells. This paper investigates the effectiveness of this method in suppressing output power decrease during partial shading. The results of the study revealed that this method is effective in suppressing output power decrease during partial shading.

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In this study, the influence of catalyst microstructure on carbon nanotube (CNT) growth by thermal chemical vapor deposition (Thermal CVD) was investigated. Particular emphasis was placed on clarifying the role of aluminum as a promoter in iron/aluminum (Fe/Al) bilayer catalysts. For comparison, Fe films deposited on silicon (Si) substrates and Fe films deposited on alumina (Al₂O₃) substrates were also prepared. The density and particle size distribution of catalyst nanoparticles during both catalyst activation and CNT growth in Thermal CVD, as well as the microstructure of the synthesized CNTs, were systematically examined. The results revealed that the Fe/Al bilayer catalyst exhibited the highest catalyst particle density and the smallest average particle size during both stages. These findings indicate that the Al promoter effectively suppresses agglomeration and grain growth of Fe catalyst particles during CNT synthesis, resulting in enhanced CNT growth and the formation of high-density CNT films.

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This study investigates the influence of surface materials of a curved axis roller on web behavior using finite element analysis. Stress distribution and friction force vectors were analyzed for rubber and steel curved axis rollers under different wrap angle conditions. The results indicate that both surface material and wrap angle affect the contact state between the web and the roller. As the wrap angle increases, changes in contact length may alter frictional behavior, particularly in the machine direction and cross-machine direction. The rubber roller shows relatively moderated stress distributions, whereas the steel roller tends to exhibit friction behavior dominated by slip. These tendencies suggest that surface deformation and wrap angle may play important roles in web spreading behavior, although further experimental validation is required. In particular, changes in friction force vectors in the cross-machine direction may influence the persistence of spreading-related shear forces. The present numerical results provide qualitative insight into the interaction mechanisms between the web and curved axis rollers under transport conditions.

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Aluminum is used as a primary material in various industries due to its light weight, excellent formability, corrosion resistance, and thermal and electrical conductivity. Among these applications, heat exchangers, which constitute a core market within the aluminum industry, utilize brazing. In aluminum brazing, flux is used to remove the strong oxide layer. However, using flux has drawbacks: it pollutes the work environment, requires cleaning flux residues after brazing, is economically and time inefficient, and the flux itself is expensive. Furthermore, while brazing with non-corrosive flux has the advantage of eliminating the need to clean off the flux, it has the disadvantage that flux residues make it unsuitable for precision components and food-related applications. Consequently, flux-free brazing is sought. Recent reports describe flux-free brazing techniques utilizing either fracture caused by the thermal expansion coefficient difference between the base metal and oxide layer during rapid heating, or the reduction reaction of Mg in Al alloys by the oxide layer. This study aimed to evaluate the effect of heating rate on flux-free brazing using tensile tests and X-ray CT inspection, seeking brazing conditions yielding high tensile strength. The results revealed that tensile strength correlates with the area where interfacial reactions occur, confirmed an increase in tensile strength due to rapid heating, and clarified that achieving a larger area of interfacial reaction requires high precision in the joint surface, specimen placement, and brazing atmosphere.

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This study focuses on the electrochemical detection of loxoprofen, a non-steroidal anti-inflammatory drug (NSAID), and evaluates the influence of an external magnetic field on the measurement response, with particular attention to static conditions, namely the open-circuit potential. When an external magnetic field of 0.5 T was applied, the current response associated with the oxidation of loxoprofen was significantly enhanced compared with that obtained without a magnetic field. Moreover, open-circuit potential measurements under equilibrium conditions, without applying an external current, revealed a statistically significant difference in the measured potential depending on the presence or absence of the magnetic field (p < 0.05). These results indicate that the external magnetic field affects the physicochemical environment near the electrode even under current-free conditions. The observed effects are attributed to microscopic convection induced by magnetohydrodynamic effects in the electrolyte, which enhances mass transport under diffusion-controlled conditions and alters the concentration distribution of reactants and products at the electrode interface, leading to modulation of the mixed potential. This simple approach, requiring only the application of an external magnetic field, offers a promising strategy for sensitive and non-invasive electrochemical sensing in drug analysis and biosensing.

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Upconversion phosphors are materials capable of emitting visible light with higher energy than excitation light. In this study, trace amounts of Eu³⁺ were doped into LaGdO₃:Tm³⁺, Yb³⁺ upconversion phosphors to investigate the resulting effects on luminescence intensity. Structural analysis confirmed that all samples maintained the LaGdO₃ crystal structure with seven-fold coordination sites, regardless of Eu³⁺ addition. The upconversion luminescence intensity decreased when the Eu³⁺ concentration exceeded 10^-3 mol%, whereas an enhancement was observed in the range of 10^-3 to 10^-7 mol%. Notably, the luminescence intensity at the shorter wavelength end—which requires three-photon excitation—showed a more pronounced increase compared to the two-photon-excited luminescence. These results suggest that the luminescence of upconversion phosphors can be enhanced by optimizing intermediate relaxation during the multiphoton excitation process through appropriate trace doping.

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Particle accelerators are essential for particle physics experiments, accelerating particles to high energies. Conventional accelerators exhibit large energy disspation, limiting their continuous operation. Therefore, superconducting accelerators that suppress heat generation and enable continuous operation are attracting attention. A composite metal consisting of three layers of Nb, bronze, and OFC is used for the cavity materialin bronze-processed Nb₃Sn superconducting accelerators. Nb exhibits excellent superconducting properties and reacts with Sn upon heating to form Nb₃Sn. Bronze reacts with Sn upon heating to form Cu₃Sn. OFC possesses high thermal conductivity and workability, serving as cladding and reinforcement material. To join these dissimilar materials into a three-layer structure, a highly reliable joining technique is required. Therefore, soldering and the bronze method were adopted. In the atmosphere, wetting is inhibited by the oxide film formed on the base metal surface, so flux is used. However, flux residues and gases generated by heating can cause joint degradation and furnace contamination. Therefore, this study adopted non-flux soldering, with the ultimate goal of achieving continuous Nb₃Sn formation through non-flux soldering. Focusing on the soldering stage as a precursor to this, we investigated the optimization of joint conditions for achieving continuous Cu₃Sn formation.

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Thermal conduction in solids is governed by phonon transport, which is strongly influenced by phonon mean free paths (phonon MFPs). This study quantitatively evaluates the anisotropic thermal transport of freestanding single-walled carbon nanotube (SWCNT) films using an approach based solely on experimentally obtained parameters from the same specimen. Conventional methods often require substituting undetermined elastic parameters with external data, whereas the present method integrates a resonance-based analysis of global vibrational modes to derive three-dimensional sound velocities, thermal conductivities, and phonon MFPs entirely from direct measurements. The results reveal pronounced anisotropy in thermal conductivity, with substantially lower values through the thickness than in the plane [in-plane 8.8 W /(m･K), cross-plane 0.3 W /(m･K)], and the corresponding phonon MFPs exhibit similar directional dependence[in-plane 43 W /(m･K), cross-plane 0.4 W /(m･K)], indicating long-range phonon transport in the in-plane direction. These trends suggest that the continuous CNT network within the plane supports long-wavelength phonons, while inter-bundle interfaces along the thickness direction act as dominant scattering sites that significantly shorten the phonon MFP, providing a new framework for evaluating thermal properties in anisotropic materials with nanoscale architectures.

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