Spin fluctuations in the triangular-lattice Heisenberg antiferromagnet NaCrO₂ are investigated by means of quasi-elastic neutron scattering with high energy resolution and a wide energy band. Two components with the following features are captured separately. They are pronounced at intermediate temperatures of 20 to 50 K. One, with quite an extended lifetime corresponding to ∼0.001E_ex (E_ex is the exchange energy), nearly disappears at low temperature (10 K), and the other, with an extended lifetime of ∼0.01E_ex, survives there, identified as the free Z₂ vortex and Z₂-vortex pair, respectively, in agreement with the Z₂-vortex theory. [This article briefly introduces the published paper, K. Tomiyasu et al., Phys. Rev. B 106, 054407 (2022). Please see it for details.]

In recent years, there has been a strong demand for more advanced adhesion technologies. Neutron reflectometry (NR) is a powerful tool to examine the structure of the adhesion interface because of the large penetration depth to materials and the isotope-dependent contrast mechanism. Examining the effects of absorbed water on epoxy adhesives at their interfaces with solid substrates is crucial because of their adhesive applications in various fields. The spatial distribution of absorbed water in epoxy resin thin films under high humidity was investigated by NR. The in situ NR measurement revealed the formation of an ~1 nm-thick condensed water layer at the interface with an adherend in a humid atmosphere at a relative humidity of 85%. Water absorbed by epoxy adhesives from a humid atmosphere considerably influences their structure and properties; therefore, the results of NR indicate that the effect of water at the adhesion interface should be considered to develop the adhesion technology. The recent advances in NR overcome the limitation in the applicable field in the conventional NR measurements and would unveil the further information on the fundamental mechanism of the adhesion phenomena.

To accelerate the spread use of polymer electrolyte fuel cells (PEFCs), it is essential to increase power density and durability, while reducing costs. We have succeeded in developing an innovative gas diffusion layer (GDL) with gas flow channels (GFCs) named “GDLFC⁺” fabricated on a flat separator that enabled both cost reduction and high performance. In this study, neutron radiography was used to observe the distribution of liquid water during power generation at 1–3 A cm^-2 in a cell with a size of 1.0 cm (W) x 9.7 cm (L) large enough to evaluate the actual cell. With using our GDLs and interdigitated (comb-shaped) GFCs, the distributions of liquid water were quantitatively imaged, influenced by the current density, the relative humidity, and the water repellency of the GDL. The increase in linear velocity of the oxidant gases effectively suppressed the retention of liquid water at the cathode. The water-repellent GDL effectively made possible the back-diffusion of water over the entire electrode area, contributing not only to a large reduction in diffusion overvoltage but also in Ohmic overvoltage, resulting in high current density and high stability of a PEFC.

PcyA is an enzyme that biosynthesizes phycocyanobilin, a pigment used in photosynthesis and photosensing from the heme metabolite biliverdin. A single residue mutation of key amino acids within PcyA alters the electronic absorption spectra in the state in complex with biliverdin. The differences in the spectra have been proposed to reflect differences in the protonation states of the biliverdin bound to the PcyA mutants, however, to date, there have been no examples of the protonation states of the biliverdin bound to the PcyA mutants being visualized. In this study, the protonation states near the biliverdin-binding site of the two mutants was successfully visualized and proved the hypothesis by a combination of neutron crystallography and computational chemistry.