Rediscovery of Hall-Petch strengthening in bulk ultrafine grained pure Mg at cryogenic temperature; A Combined neutron diffraction and electron microscopy study

Zheng, R.*; Gong, W.; Du, J.-P.*; Gao, S.*; Liu, M.*; Li, G.*; Kawasaki, Takuro; Harjo, S.; Ma, C.*; Ogata, Shigenobu*; et al.

Acta Materialia, 238, p.118243_1 - 118243_15, 2022/10

https://doi.org/10.1016/j.actamat.2022.118243

Phase transition and chemical reactivity of 1H-tetrazole under high pressure up to 100 GPa

Gao, D.*; Tang, X.*; Wang, X.*; Yang, X.*; Zhang, P.*; Che, G.*; Han, J.*; Hattori, Takanori; Wang, Y.*; Dong, X.*; et al.

Physical Chemistry Chemical Physics, 23(35), p.19503 - 19510, 2021/09

https://doi.org/10.1039/D1CP02913D

Pressure-induced phase transition and polymerization of nitrogen-rich molecules are widely focused due to its extreme importance for the development of green high energy density materials. Here, we present a study of the phase transition and chemical reaction of 1H-tetrazole up to 100 GPa by using Raman, IR, X-ray diffraction, neutron diffraction techniques and theoretical calculation. A phase transition above 2.6 GPa was identified and the high-pressure structure was determined with one molecule in a unit cell. The 1H-tetrazole polymerizes reversibly below 100 GPa, probably through a carbon-nitrogen bonding instead of nitrogen-nitrogen bonding. Our studies updated the structure model of the high pressure phase of 1H-tetrazole, and presented the possible intermolecular bonding route for the first time, which gives new insights to understand the phase transition and chemical reaction of nitrogen-rich compounds, and benefit for designing new high energy density materials.

Coordination number regulation of molybdenum single-atom nanozyme peroxidase-like specificity

Wang, Y.*; Jia, G.*; Cui, X.*; Zhao, X.*; Zhang, Q.*; Gu, L.*; Zheng, L.*; Li, L. H.*; Wu, Q.*; Singh, D. J.*; et al.

Chem, 7(2), p.436 - 449, 2021/02

https://doi.org/10.1016/j.chempr.2020.10.023

Pressure-induced Diels-Alder reactions in CH - CF cocrystal towards graphane structure

Wang, Y.*; Dong, X.*; Tang, X.*; Zheng, H.*; Li, K.*; Lin, X.*; Fang, L.*; Sun, G.*; Chen, X.*; Xie, L.*; et al.

Angewandte Chemie; International Edition, 58(5), p.1468 - 1473, 2019/01

https://doi.org/10.1002/anie.201813120

Pressure-induced polymerization (PIP) of aromatics is a novel method to construct sp-carbon frameworks, and nanothreads with diamond-like structures were synthesized by compressing benzene and its derivatives. Here by compressing benzene-hexafluorobenzene cocrystal(CHCF), we identified H-F-substituted graphane with a layered structure in the PIP product. Based on the crystal structure determined from the in situ neutron diffraction and the intermediate products identified by the gas chromatography-mass spectrum, we found that at 20 GPa CHCF forms tilted columns with benzene and hexafluorobenzene stacked alternatively, which leads to a [4+2] polymer, and then transfers to short-range ordered hydrogenated-fluorinated graphane. The reaction process contains [4+2] Diels-Alder, retro-Diels-Alder, and 1-1' coupling, and the former is the key reaction in the PIP. Our studies confirmed the elemental reactions of the CHCF for the first time, which provides a novel insight into the PIP of aromatics.

High-j proton alignments in Pd

Zhou, H. B.*; Zhou, X. H.*; Zhang, Y. H.*; Zheng, Y.*; Liu, M. L.*; Zhang, N. T.*; Chen, L.*; Wang, S. T.*; Li, G. S.*; Wang, H. X.*; et al.

European Physical Journal A, 47(9), p.107_1 - 107_7, 2011/09

https://doi.org/10.1140/epja/i2011-11107-3

High-spin states in Pd have been investigated by means of in-beam -ray spectroscopic techniques. The previously known and 1/2[550] bands were extended to higher spins. The band crossings observed experimentally are explained by the alignment of protons. The band properties in Pd are compared with those in the neighboring nuclei and are discussed within the framework of the cranked shell model.

Abundances of rare earth elements in crude oils and their partitions in water

Nakada, Ryoichi*; Takahashi, Yoshio*; Zheng, G.*; Yamamoto, Yuhei; Shimizu, Hiroshi*

Geochemical Journal, 44(5), p.411 - 418, 2010/10

https://doi.org/10.2343/geochemj.1.0083

Patterns of the entire range of REE in crude oils and coexisting water, collected from mud volcanoes in Xinjiang Province of China, are reported here for the first time. Crude oils show light REE enriched patterns with flat or depleted patterns in heavy REE, when normalized to chondrite. The REE concentrations in crude oils are larger than those in coexisting water by a factor of more than one hundred. Considering the hydrophobicity of oil and the high ionic characteristics of REE, it is strongly suggested that REE form complexes with ligands present in the crude oils. Based on the C NMR spectroscopy, it is found that small amounts of phenol and carboxyl groups are contained in the crude oil samples, which could possibly provide complexing sites for REE. REE patterns of crude oils are similar to those of coexisting mud samples collected from the same mud volcanoes, which suggests that the REE in crude oils are derived from rocks and sediments where crude oils were generated.

Progress of understanding negative triangular tokamak configuration

Kikuchi, Mitsuru; Fasoli, A.*; Takizuka, Tomonori*; Diamond, P.*; Medvedev, S.*; Duan, X.*; Zushi, Hideki*; Furukawa, Masaru*; Kishimoto, Yasuaki*; Wu, Y.*; et al.

no journal, , 

Power and particle control is challenging for standard D-shaped H-mode scenario in tokamak. Possibility of negative triangularity as innovative tokamak concept is discussed by Kikuchi et al. Experimental and numerical studies of negative triangular plasma at CRPP-EPFL success-fully demonstrated improved connement and the weakening of the SOL flow acceleration is implied for the negative triangularity. Recent studies on mechanism of type II and grassy ELM show importance of closure of second stability access to achieve small ELM regimes and also kinetic effects. Medvedev showed that closure of second stability also occurs for negative triangularity. But the MHD stability in negative triangularity is a bit more complicated so that closure of second stability does not imply easy access to small ELM regimes. We discuss critical elements behind.