Massive Dirac magnons in the three-dimensional honeycomb magnetic oxide FeTiO

Chung, J.-H.*; Kwangwoo, S.*; Yokoo, Tetsuya R.; Ueta, Daichi*; Imai, Masaki; Kim, H.-S.; Kiem, D. H.; Han, M. J.*; Shamoto, Shinichi

Scientific Reports (Internet), 15, p.5978_1 - 5978_10, 2025/02

https://doi.org/10.1038/s41598-025-90478-2

Brightening triplet excitons enable high-performance white-light emission in organic small molecules via integrating n-- transitions

Yang, Q.*; Yang, X.*; Wang, Y.*; Fei, Y.*; Li, F.*; Zheng, H.*; Li, K.*; Han, Y.*; Hattori, Takanori; Zhu, P.*; et al.

Nature Communications (Internet), 15, p.7778_1 - 7778_9, 2024/09

https://doi.org/10.1038/s41467-024-52196-7

Luminescent materials that simultaneously embody bright singlet and triplet excitons hold great potential in optoelectronics, signage, and information encryption. However, achieving high-performance white-light emission is severely hampered by their inherent unbalanced contribution of fluorescence and phosphorescence. Herein, we address this challenge by pressure treatment engineering via hydrogen bonding cooperativity effect to realize the mixture of n-- transitions, where the triplet state emission was boosted from 7% to 40% in isophthalic acid (IPA). A superior white-light emission based on hybrid fluorescence and phosphorescence was harvested in pressure-treated IPA, and the photoluminescence quantum yield was increased to 75% from the initial 19% (blue-light emission). In-situ high-pressure IR spectra, X ray diffraction, and neutron diffraction reveal continuous strengthening of the hydrogen bonds with the increase of pressure. Furthermore, this enhanced hydrogen bond is retained down to the ambient conditions after pressure treatment, awarding the targeted IPA efficient intersystem crossing for balanced singlet/triplet excitons population and resulting in efficient white-light emission. This work not only proposes a route for brightening triplet states in organic small molecule, but also regulates the ratio of singlet and triplet excitons to construct high-performance white-light emission.

Spectral evidence for Dirac spinons in a kagome lattice antiferromagnet

Zeng, Z.*; Zhou, C.*; Zhou, H.*; Han, L.*; Chi, R.*; Li, K.*; Kofu, Maiko; Nakajima, Kenji; Wei, Y.*; Zhang, W.*; et al.

Nature Physics, 20(7), p.1097 - 1102, 2024/07

https://doi.org/10.1038/s41567-024-02495-z

Characteristics of temporal variability of long-duration bursts of high-energy radiation associated with thunderclouds on the Tibetan plateau

Tsuchiya, Harufumi; Hibino, Kinya*; Kawata, Kazumasa*; Onishi, Munehiro*; Takita, Masato*; Munakata, Kazuoki*; Kato, Chihiro*; Shimoda, Susumu*; Shi, Q.*; Wang, S.*; et al.

Progress of Earth and Planetary Science (Internet), 11, p.26_1 - 26_14, 2024/05

https://doi.org/10.1186/s40645-024-00625-y

Intrinsic factors responsible for brittle versus ductile nature of refractory high-entropy alloys

Tsuru, Tomohito; Han, S.*; Matsuura, Shutaro*; Chen, Z.*; Kishida, Kyosuke*; Lobzenko, I.; Rao, S.*; Woodward, C.*; George, E.*; Inui, Haruyuki*

Nature Communications (Internet), 15, p.1706_1 - 1706_10, 2024/02

https://doi.org/10.1038/s41467-024-45639-8

Refractory high-entropy alloys (RHEAs) have attracted attention because of their potential for use in ultrahigh-temperature applications. Unfortunately, their body-centered-cubic (BCC) crystal structures make them more brittle than the ductile and fracture-resistant face-centered-cubic (FCC) HEAs. RHEAs also display significantly lower creep strengths than a leading Ni-base superalloy and its FCC matrix. To overcome these drawbacks and develop RHEAs into viable structural materials, improved fundamental understanding is needed of factors that control strength and ductility. Here we investigate two model RHEAs, TiZrHfNbTa and VNbMoTaW, and show that the former is plastically compressible down to 77 K, whereas the latter is not below 298 K. We find that hexagonal close-packed (HCP) elements in TiZrHfNbTa lower its dislocation core energy, increase its lattice distortion, and lower its shear modulus relative to VNbMoTaW whose elements are all BCC, leading to the formers higher ductility and modulus-normalized yield strength. Consistent with our yield strength models, primarily screw dislocations are present in TiZrHfNbTa after deformation, but equal numbers of edge and screw segments in VNbTaMoW. Dislocation cores are compact in VNbTaMoW and extended in TiZrHfNbTa, and different macroscopic slip planes are activated in the two RHEAs, which we attribute to the concentration of HCP elements. Our findings demonstrate how electronic structure changes related to the ratio of HCP to BCC elements can be used to control strength, ductility, and slip behavior to develop the next generation of high-temperature materials for more efficient power plants and transportation.

PANDORA Project for the study of photonuclear reactions below

Tamii, Atsushi*; Pellegri, L.*; Sderstrm, P.-A.*; Allard, D.*; Goriely, S.*; Inakura, Tsunenori*; Khan, E.*; Kido, Eiji*; Kimura, Masaaki*; Litvinova, E.*; et al.

European Physical Journal A, 59(9), p.208_1 - 208_21, 2023/09

https://doi.org/10.1140/epja/s10050-023-01081-w

no abstracts in English

Mechanical surface treatment studies by Bragg edge neutron imaging

Ramadhan, R. S.*; Glaser, D.*; Soyama, Hitoshi*; Kockelmann, W.*; Shinohara, Takenao; Pirling, T.*; Fitzpatrick, M. E.*; Tremsin, A. S.*

Acta Materialia, 239, p.118259_1 - 118259_12, 2022/10

https://doi.org/10.1016/j.actamat.2022.118259

Assessment of radioactive contamination and effectiveness of remedial measures in urban environments, Report of Working Group 2, Modelling and Data for Radiological Impact Assessments (MODARIA) Programme

Boznar, M. Z.*; Charnock, T. W.*; Chouhan, S. L.*; Grsic, Z.*; Halsall, C.*; Heinrich, G.*; Helebrant, J.*; Hettrich, S.*; Kua, P.*; Mancini, F.*; et al.

IAEA-TECDOC-2001, 226 Pages, 2022/06

https://www.iaea.org/publications/15122/assessment-of-radioactive-contamination-and-effectiveness-of-remedial-measures-in-urban-environments

The IAEA organized a programme from 2012 to 2015 entitled Modelling and Data for Radiological Impact Assessments (MODARIA), which aimed to improve capabilities in the field of environmental radiation dose assessment by acquiring improved data, model testing and comparison of model inputs, assumptions and outputs, reaching a consensus on modelling philosophies, aligning approaches and parameter values, developing improved methods and exchanging information. This publication describes the activities of Working Group 2, Exposures in Contaminated Urban Environments and Effect of Remedial Measures.

The Fe(n,)Fe cross section from the surrogate ratio method and its effect on the Fe nucleosynthesis

Yan, S. Q.*; Li, X. Y.*; Nishio, Katsuhisa; Lugaro, M.*; Li, Z. H.*; Makii, Hiroyuki; Pignatari, M.*; Wang, Y. B.*; Orlandi, R.; Hirose, Kentaro; et al.

Astrophysical Journal, 919(2), p.84_1 - 84_7, 2021/10

https://doi.org/10.3847/1538-4357/ac12ce

Evaluation report of Task 9B based on comparisons and analyses of modelling results for the sp HRL LTDE-SD experiments

Soler, J. M.*; Meng, S.*; Moreno, L.*; Neretnieks, I.*; Liu, L.*; Keklinen, P.*; Hokr, M.*; ha, J.*; Vetenk, A.*; Reimitz, D.*; et al.

SKB TR-20-17, 71 Pages, 2021/07

Task 9B of the SKB Task Force on Modelling of Groundwater Flow and Transport of Solutes in fractured rock focused on the modelling of experimental results from the LTDE-SD in situ tracer test performed at the sp Hard Rock Laboratory in Sweden. Ten different modelling teams provided results for this exercise, using different concepts and codes. Three main types of modelling approaches were used: (1) analytical solutions to the transport-retention equations, (2) continuum-porous-medium numerical models, and (3) microstructure-based models accounting for small-scale heterogeneity (i.e. mineral grains and microfracture distributions). The modelling by the different teams allowed the comparison of many different model concepts, especially in terms of potential zonations of rock properties (porosity, diffusion, sorption), such as the presence of a disturbed zone at the rock and fracture surface, the potential effects of micro- and cm-scale fractures.