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535 results on '"Németh, K."'

2. Li3BN2 as a Transition Metal Free, High Capacity Cathode for Li-ion Batteries

Author

Emani, S, Liu, C, Ashuri, M, Sahni, K, Wu, J, Yang, W, Németh, K, and Shaw, LL

Subjects
Li3BN2, Cathodes, Transition metal free electrodes, Li-ion batteries, Other Chemical Sciences, Analytical Chemistry, Physical Chemistry, Physical Chemistry (incl. Structural)
Abstract

Li3BN2 is investigated for the first time as a transition metal free, high capacity cathode material for Li-ion batteries. It is shown that α-Li3BN2 can exhibit a specific capacity of 890 mA h g−1 with the charge storage mechanism associated with the valence state change of N ions in the BN2 anion. The specific capacity demonstrated in this study is the highest one ever reported in literature for an intercalation-type cathode material. Further, using the valence state change of N ions as a charge storage mechanism opens the door for designing additional high performance, transition metal free electrodes in the future.

Published
2019

4. Pressure-induced transition from the dynamic to static Jahn-Teller effect in (Ph$_{4}$P)$_{2}$IC$_{60}$

Author

Francis, E. A., Scharinger, S., Németh, K., Kamarás, K., and Kuntscher, C. A.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

High-pressure infrared transmission measurements on \PhC60 were performed up to 9 GPa over a broad frequency range (200 - 20000 cm$^{-1}$) to monitor the vibrational and electronic/vibronic excitations under pressure. The four fundamental T$_{1u}$ modes of \C60a\ are split into doublets already at the lowest applied pressure and harden with increasing pressure. Several cation modes and fullerene-related modes split into doublets at around 2 GPa, the most prominent one being the G$_{1u}$ mode. The splitting of the vibrational modes can be attributed to the transition from the dynamic to static Jahn-Teller effect, caused by steric crowding at high pressure. Four absorption bands are observed in the NIR-VIS frequency range. They are discussed in terms of transitions between LUMO electronic states in \C60a, which are split because of the Jahn-Teller distortion and can be coupled with vibrational modes. Various distortions and the corresponding symmetry lowering are discussed. The observed redshift of the absorption bands indicates that the splitting of the LUMO electronic states is reduced upon pressure application., Comment: 10 pages, 17 figures

Published
2012
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9. Tectonically-determined distribution of monogenetic volcanoes in a compressive tectonic regime: An example from the Pannonian continental back-arc system (Central Europe)

Author

Hencz, M., Biró, T., Németh, K., Porkoláb, K., Kovács, I.J., Spránitz, T., Cloetingh, S., Szabó, C., Berkesi, M., Hencz, M., Biró, T., Németh, K., Porkoláb, K., Kovács, I.J., Spránitz, T., Cloetingh, S., Szabó, C., and Berkesi, M.

Abstract

This paper presents the results from a geographic information systems (GIS) workflow, which was used to analyze the spatial distribution and temporal evolution of volcanoes in the Mio-Pleistocene monogenetic Bakony-Balaton Highland Volcanic Field (BBHVF), located in the Pannonian Basin, Hungary. Volcanism occurred during the tectonic inversion in a back-arc setting and a compressive/transpressive tectonic regime on the hottest and thinnest lithosphere of continental Europe. The main goal of this study is to clarify the effect of the pre-existing structure of the upper lithosphere in the distribution of the volcanic centers across the volcanic field using an innovative GIS methodology. Orientation of the volcanic field was compared to the orientation of the faults in the BBHVF, and in its larger vicinity, which resulted in correspondence, suggesting the dominance of the SW-NE direction. The directions of the volcanic lineaments fit well to the two main fault directions. The fault-volcano proximity analysis suggests that the fault plane of a thrust fault was an important structural feature during the lifespan of the volcanism. All results suggest that the fault plane of a regionally significant Cretaceous thrust fault (Litér Fault) might have served as a temporary pathway for the ascending magma, whereby (similarly to other, smaller faults) redirecting the magmas causing clustering of the volcanoes. This highlights the importance of major upper crustal structural heterogeneities for magma transport in a compressive tectonic system, especially in the case of active, monogenetic volcanic fields from a volcanic hazard perspective. The present GIS workflow can be effective in analyzing the spatial patterns of the volcanism and its connection with crustal structures at monogenetic volcanic fields worldwide.

Published
2023

21. Jahn-Teller Distorted Excited States of C60

Author

Surján, P. R., Németh, K., Udvardi, L., Cardona, Manuel, editor, Fulde, Peter, editor, von Klitzing, Klaus, editor, Queisser, Hans-Joachim, editor, Lotsch, Helmut K. V., editor, Kuzmany, Hans, editor, Fink, Jörg, editor, Mehring, Michael, editor, and Roth, Siegmar, editor

Published
1993
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32. The relationship between cognitive control and lexical conflict resolution in developmental dyslexia.

Author

Dobó, D., Ladányi, E., Szőllősi, Á., Lukics, K.S., Németh, K., and Lukács, Á.

Subjects
EXECUTIVE function, COGNITION, LANGUAGE acquisition, T-test (Statistics), DYSLEXIA, DESCRIPTIVE statistics, DATA analysis software
Abstract

Previous studies have revealed that cognitive control functions contribute to the resolution of lexical interference. Both cognitive control (CC) deficits and reduced speed of lexical retrieval in Rapid Automatized Naming (RAN) tasks are characteristics of Developmental Dyslexia (DD), but it is still not fully understood how these deficits relate to each other and to reading problems. To examine this question, we tested adolescents with DD (n = 38), poor readers (PR; n = 25) and typical readers (TR; n = 33) matched on age and IQ, on CC functions with Stroop, Stop Signal, Simon, Backward Digit Span and n-back tasks and on lexical retrieval and lexical conflict resolution with RAN of pictures in semantically homogeneous vs. mixed trials. As expected, in the blocked RAN Task DD individuals showed longer naming times and a greater effect of lexical conflict resolution (indexed by difference scores of naming times in the homogeneous and mixed conditions) than TR participants. We also found significant group differences (TR = PR > DD) in CC measures. Naming time was associated with CC, while the lexical interference effect did not show any association with this set of abilities. These findings suggest that DD individuals show impairments in multiple cognitive functions, such as cognitive control, lexical retrieval and lexical conflict resolution. Our results also suggest that CC functions are involved in lexical retrieval, but we have not found evidence for their involvement in lexical conflict resolution processes. [ABSTRACT FROM AUTHOR]

Published
2022
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36. Li3 BN2 as a Transition Metal Free, High Capacity Cathode for Li-ion Batteries

Author

Emani, S, Liu, C, Ashuri, M, Sahni, K, Wu, J, Yang, W, Németh, K, and Shaw, LL

Subjects
Cathodes, Transition metal free electrodes, Li-ion batteries, Other Chemical Sciences, Physical Chemistry, Li3BN2, Analytical Chemistry, Physical Chemistry (incl. Structural)
Abstract

© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Li 3 BN 2 is investigated for the first time as a transition metal free, high capacity cathode material for Li-ion batteries. It is shown that α-Li 3 BN 2 can exhibit a specific capacity of 890 mA h g −1 with the charge storage mechanism associated with the valence state change of N ions in the BN 2 anion. The specific capacity demonstrated in this study is the highest one ever reported in literature for an intercalation-type cathode material. Further, using the valence state change of N ions as a charge storage mechanism opens the door for designing additional high performance, transition metal free electrodes in the future.

Published
2019
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47. Deception Island, Antarctica: eruptive dynamics and volcanic hazards in a post-caldera monogenetic volcanic field

Author

Pedrazzi, Dario, Németh, K., Geyer, Adelina, Álvarez-Valero, A. M., Aguirre-Díaz, Gerardo, Bartolini, Stefania, Geyer, Adelina, Pedrazzi, Dario, Bartolini, Stefania, Geyer, Adelina [0000-0002-8803-6504], Pedrazzi, Dario [0000-0002-6869-1325], and Bartolini, Stefania [0000-0002-0454-4561]

Subjects
South Shetland Islands, Crimson Hill, Kroner Lake
Abstract

Deception Island (DI) is an active Quaternary volcanic caldera of the South Shetlands Archipelago (Antarctica) (Fig. 1a, b).Post-caldera volcanism includes over 30 eruptions during the Holocene (e.g. Orheim 1972) with more than 20 volcanic episodes registered over the past two centuries (Orheim 1972; Roobol 1982; Smellie et al. 2002) including the eruptions of 1967, 1969, and 1970 (Fig. 1c). These eruptions, together with the 1992, 1999 (Ibáñez et al. 2003), and 2014–2015 (Almendros et al. 2015) unrest episodes, demonstrate that the volcanic system under DIis still very active and that the occurrence of a new eruption is likely. Recent post-caldera volcanism is dominated by hydromagmatic eruptions, with the water source being from Port Foster Bay seawater, from the underground aquifer and water from the glaciers (Baker et al. 1975; Smellie 2002; Pedrazzi et al. 2014). Even small-volume eruptions become highly explosive when located on waterlogged shorelines, or beneath ice caps (Baker et al. 1975; Smellie 2002; Pedrazzi et al. 2014). A detailed field revision of the historical (1829–1970) hydrovolcanic post-caldera volcanism at DI was carried out, with the aim of understanding how the location of a potential new eruptive vent can control magma-water interactions, and the related hazards to be expected during a new eruption on the island.

Published
2018

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