Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf
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Year | 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | <=2018 | |
Type of publication | Articles ref. in Journals | Conference abstracts in ref. journals | Books | Proceedings | Wissenschaftlich-Technische Berichte/ HZDR-Reports | Lectures | Posters | Patents | Research data | Software | RODARE publications | |
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Only approved publications
42247 Publications
Nuclear magnetic resonance spectroscopy in pulsed magnetic fields
Kühne, H.; Ihara, Y.
Abstract
This article provides an introduction to nuclear magnetic resonance spectroscopy in pulsed magnetic fields (PFNMR), focussing on its capabilities, applications, and future developments in research involving high magnetic fields. It highlights the significance of PFNMR in enhancing the understanding of solid-state materials, with particular emphasis on those exhibiting complex interactions and strong electronic correlations. Several technical aspects are discussed, including the challenges associated with high-frequency NMR experiments. The power of PFNMR is showcased through several examples, including studies on the topical materials LiCuVO4, SrCu2(BO3)2, and CeIn3, offering insights into their magnetic and electronic properties at high magnetic fields. The article also discusses possible future directions for the technique, including improvements in PFNMR instrumentation and the exploration of materials under extreme conditions. This exposition underscores the role of PFNMR in advancing the frontiers of materials-science research.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Contemporary Physics 65(2024), 40-61
DOI: 10.1080/00107514.2024.2393009
Downloads
- Secondary publication expected from 05.09.2025
Permalink: https://www.hzdr.de/publications/Publ-39827
Data publication: Curvature-induced parity loss and hybridization of magnons: Exploring the connection of flat and tubular magnetic shells
Brevis, F.; Landeros, P.; Lindner, J.; Kakay, A.; Körber, L.
Abstract
This archive contains the raw data as well as the Tetrax (www.tetrax.software) Jupyter notebooks to produce the data that has been analyzed and used for the manuscript: Curvature-induced parity loss and hybridization of magnons: Exploring the connection of flat and tubular magnetic shells, Physical Review B 110, 134428 (2024), published on 17 October, 2024.
Keywords: curvature-induced; spin waves; mignons; hybridization; parity
Related publications
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Curvature-induced parity loss and hybridization of magnons: Exploring the …
ROBIS: 39818 has used this (Id 39826) publication of HZDR-primary research data
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Software in the HZDR data repository RODARE
Publication date: 2024-10-17 Open access
DOI: 10.14278/rodare.3232
Versions: 10.14278/rodare.3233
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39826
Unusual metallic state in superconducting A15-type La4H23
Guo, J.; Semenok, D.; Shutov, G.; Zhou, D.; Chen, S.; Wang, Y.; Zhang, K.; Wu, W.; Luther, S.; Helm, T.; Huang, X.; Cui, T.
Abstract
Hydride superconductors continue to fascinate the communities of condensed matter physics and material scientists because they host the promising near room-temperature superconductivity. Current research has concentrated on the new hydride superconductors with the enhancement of the superconducting transition temperature (Tc). The multiple extreme conditions (high pressure/temperature and magnetic field) will introduce new insights into hydride superconductors. The study of transport properties under very high magnetic fields facilitates the understanding of superconductivity in conventional hydride superconductors. In the present work, we report experimental evidence of an unusual metal state in a newly synthesized cubic A15-type La4H23 that exhibits superconductivity with a Tc reaching 105 K at 118 GPa. A large negative magnetoresistance is observed in strong pulsed magnetic fields in the non-superconducting state of this compound below 40 K. Moreover, we construct the full magnetic phase diagram of La4H23 up to 68 T at high pressure. The present work reveals anomalous electronic structural properties of A15-La4H23 under high magnetic fields, and therefore has great importance with regard to advancing the understanding of quantum transport behaviors in hydride superconductors.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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National Science Review 11(2024), nwae149
DOI: 10.1093/nsr/nwae149
Permalink: https://www.hzdr.de/publications/Publ-39825
Possible realization of a randomness-driven quantum disordered state in the S = 1/2 antiferromagnet Sr3CuTa2O9
Sana, B.; Barik, M.; Lee, S.; Jena, U.; Baenitz, M.; Sichelschmidt, J.; Luther, S.; Kühne, H.; Sethupathi, K.; Ramachandra Rao, M. S.; Choi, K. Y.; Khuntia, P.
Abstract
Collective behavior of spins, frustration-induced strong quantum fluctuations, and subtle interplay between competing degrees of freedom in quantum materials can lead to correlated quantum states with exotic excitations that are essential ingredients for establishing paradigmatic models and have immense potential for quantum technologies. Disorder is ubiquitous in real materials, and the detailed insights into the role of disorder on the intriguing ground state borne out of quenched randomness provide a route towards the design and discovery of functional quantum materials. Herein we report magnetization, specific heat, electron spin resonance, and muon spin resonance studies on a 3d-electron-based antiferromagnet Sr3CuTa2O9. The negative value of Curie-Weiss temperature, obtained from the Curie-Weiss fit of high-temperature magnetic susceptibility data indicates the presence of antiferromagnetic interaction between Cu2+ moments. Specific heat data show the absence of long-range magnetic ordering down to 64 mK despite a reasonably strong exchange interaction between Cu2+ (S = 1/2) spins as reflected from a Curie-Weiss temperature of −27 ± 1 K. The power-law behavior and the data collapse of specific heat and magnetization data evince the emergence of a random-singlet state in Sr3CuTa2O9. The power-law-like spin autocorrelation function and the data collapse of muon polarization asymmetry with longitudinal field dependence of t/(μ0H)γ further support credence to the presence of a randomness-induced quantum disordered state. Our results suggest that randomness induced by disorder is an alternate route to realize quantum spin disordered state in this antiferromagnet.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review B 110(2024), 134412
DOI: 10.1103/PhysRevB.110.134412
arXiv: https://arxiv.org/abs/2304.13116
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Permalink: https://www.hzdr.de/publications/Publ-39824
Quasistatic magnetism in the breathing pyrochlore antiferromagnets LiGa1−xInxCr4O8 (x = 0.2, 0.5)
Lee, W.; Yoon, S.; Choi, Y.-S.; Do, S.-H.; Ponomaryov, O.; Zvyagin, S.; Gorbunov, D.; Wosnitza, J.; Koda, A.; Chen, W.-T.; Lee, S.
Abstract
We report magnetic susceptibility, high-field magnetization, muon spin relaxation, and electron spin resonance measurements of the breathing pyrochlore antiferromagnets LiGa1−xInxCr4O8 (x = 0.2, 0.5). Unlike the previously proposed spin-glass-like phase for 0.1 < x < 0.75, we find no signature for spin glassiness and phase segregation in both the x = 0.2 and 0.5 compounds. Instead, we identify a two-step magnetic transition with a partial spin freezing at T∗ = 12 K (x = 0.2) and 9 K (x = 0.5) followed by quasistatic order at Tm = 6 K (x = 0.2) and 3 K for (x = 0.5). In addition, for Tm < T < T∗, we observe evidence of a competition between fast and slow spin dynamics, suggesting a thermal and temporal distribution of spin correlations. Our findings underscore the possibility of realizing novel magnetic phases by tuning bond alternation and introducing bond disorder through chemical substitution.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review B 110(2024), 144435
DOI: 10.1103/PhysRevB.110.144435
Permalink: https://www.hzdr.de/publications/Publ-39823
Giant magnetocaloric effect of Ni-Co-Mn-Ti all-d Heusler alloys in high magnetic fields
Beckmann, B.; Taubel, A.; Gottschall, T.; Pfeuffer, L.; Koch, D.; Staab, F.; Bruder, E.; Scheibel, F.; Skokov, K. P.; Gutfleisch, O.
Abstract
Ni-Co-Mn-Ti all-d Heusler alloys are attracting considerable attention for solid-state caloric cooling applications due to their promising combination of excellent caloric and mechanical properties. Here, we report on the maximum attainable magnetocaloric effect in Ni37Co13Mn34.5Ti15.5, which shows a first-order magnetostructural martensitic transformation around room temperature. Heat capacity measurements reveal a giant transition entropy change of 43.5 J(kgK)−1 and are utilized to estimate the magnetocaloric effect as well as the magnetic fields required to saturate it in isothermal and adiabatic conditions. Confirming the results based on this approach, we achieve maximum isothermal entropy changes and directly measured adiabatic temperature changes of 37.8 J(kgK)−1 and −20.2 K, respectively. Thus, the herein reported maximum attainable magnetocaloric effect outperforms classical Ni-Mn-based Heusler alloys, such as Ni(-Co)-Mn-In. Especially the saturated adiabatic temperature change surpasses all previously published values of magnetic field-induced first-order phase transitions measured around room temperature in pulsed magnetic fields in recent years. Thereby, we demonstrate that Ni(-Co)-Mn-Ti Heusler alloys are particularly suitable for the application of sufficiently large external stimuli to fully induce the phase transition and exploit their intrinsically large caloric effect.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Acta Materialia 282(2024), 120460
DOI: 10.1016/j.actamat.2024.120460
Permalink: https://www.hzdr.de/publications/Publ-39822
Absence of Fermi surface reconstruction in pressure-driven overdoped YBCO
Tozer, S. W.; Coniglio, W. A.; Förster, T.; Bonn, D. A.; Hardy, W. N.; Liang, R.; Kampert, W. A. G.; Grockowiak, A. D.
Abstract
The evolution of the critical superconducting temperature and field, quantum oscillation frequencies, and effective mass m∗ in underdoped YBa2Cu3O7−δ (YBCO) crystals (p = 0.11, with p the hole concentration per Cu atom) points to a partial suppression of the charge orders with increasing pressure up to 7 GPa, mimicking doping. Application of pressures up to 25 GPa pushes the sample to the overdoped side of the superconducting dome. In contrast to other cuprates, or to doping studies on YBCO, the frequencies of the quantum oscillations measured in that pressure range do not support the picture of a Fermi-surface reconstruction in the overdoped regime, but possibly point to the existence of a new charge order.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review B 110(2024), 144508
DOI: 10.1103/PhysRevB.110.144508
arXiv: https://arxiv.org/abs/2312.01439
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Permalink: https://www.hzdr.de/publications/Publ-39821
Curvature-induced parity loss and hybridization of magnons: Exploring the connection of flat and tubular magnetic shells
Brevis, F.; Landeros, P.; Lindner, J.; Kakay, A.; Körber, L.
Abstract
This paper delves into the connection between flat and curvilinear magnetization dynamics. For this, we numerically study the evolution of the magnon spectrum of rectangular waveguides upon rolling its cross section up to a full tube. Magnon spectra are calculated over a wide range of magnetization states using a finite-element dynamic-matrix method, which allows us to trace the evolution of the magnon frequencies and several critical magnetic fields with increasing curvature. By analyzing the parity of the higher-order magnon modes, we find a curvature-induced mode heterosymmetry that originates from a chiral contribution to the exchange interaction and is related to the Berry phase of magnons in closed loops. Importantly, this curvature-induced parity loss has profound consequences for the linear coupling between different propagating magnons, allowing for hybridization between initially orthogonal modes. In this context, we demonstrate the integral role of edge modes in forming the magnon spectrum in full tubes. Our findings provide theoretical insights into curvilinear magnetization dynamics and are relevant for interpreting and designing experiments in the field.
Keywords: Curvature-induced; parity; hybridization; spin waves
Related publications
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Data publication: Curvature-induced parity loss and hybridization of magnons …
ROBIS: 39826 HZDR-primary research data are used by this (Id 39818) publication -
Data publication: Curvature-induced parity loss and hybridization of magnons …
RODARE: 3233 HZDR-primary research data are used by this (Id 39818) publication
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Physical Review B 110(2024), 134428
DOI: 10.1103/PhysRevB.110.134428
Downloads
- Secondary publication expected from 17.10.2025
Permalink: https://www.hzdr.de/publications/Publ-39818
Focused electron beam induced deposition of magnetic tips for improved magnetic force microscopy
Escalante-Quiceno, A. T.; Fernández, V. V.; Martín, J. I.; Hierro-Rodriguez, A.; Hlawacek, G.; Jaafar, M.; Asenjo, A.; Magén, C.; de Teresa, J. M.
Abstract
The combination of focused electron beam induced deposition (FEBID) and magnetic force microscopy (MFM) has opened up new possibilities in nanoscale magnetic imaging. FEBID offers precise control over the dimensions and magnetic properties of the MFM probes, enabling the development of high-performance magnetic tips with enhanced capabilities compared to conventional ones. These improved tips offer superior resolution, sensitivity, and versatility in nanoscale magnetic surface characterization. Here, we compare the performance of a commercial MFM tip and a FEBID-grown Fe tip in a Ni80Fe20/NdCo5 film. The FEBID tip exhibited superior lateral resolution for topography imaging, likely due to its sharper and well-defined geometry, with a tip diameter of approximately 20 nm. MFM measurements further confirmed this advantage, revealing better-defined magnetic domains and higher magnetic contrast with the FEBID-functionalized probes compared to the commercial tip. This improvement can be attributed to the possibility to optimize the tip-sample magnetic interaction for the FEBID tip. By reducing the lift height of the second pass, we were able to bring the tip closer to the sample, enhancing the magnetic signal without introducing significant topographic artifacts. Overall, these findings highlight the potential of FEBID for creating high-resolution and high-sensitivity MFM tips.
Keywords: Magnetic anisotropy; Magnetic materials; Image processing; Electron beam-induced deposition; Alloys
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39804) publication
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Low Temperature Physics 50(2024), 919-927
DOI: 10.1063/10.0028622
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Permalink: https://www.hzdr.de/publications/Publ-39804
Principal Component Analysis for Distributions Observed by Samples in Bayes Spaces
Pavlú, I.; Machalová, J.; Tolosana Delgado, R.; Hron, K.; Bachmann, K.; van den Boogaart, K. G.
Abstract
Particle or grain size distributions often play an important role in understanding processes in geosciences. Functional data analysis allows applying multivariate methods like principal component analysis directly to such distributions. These are however often observed in the form of samples, and thus with a sampling error. This additional sampling error changes the properties of the multivariate variance and thus the number of relevant principal components and their direction. The result of the principal component analysis becomes an artefact of the sampling error and can negatively affect the following data analysis. This work presents a way of estimating this sampling error and how to confront it in the context of principal component analysis. The effect of the sampling error and the effectiveness of the correction is demonstrated with a series of simulations. It is shown how the interpretability and reproducibility of the principal components improve and become independent of the selection of the basis. The proposed method is then applied on a dataset of grain size distributions in a geometallurgical dataset from Thaba mine in the Bushveld complex.
Keywords: Principal component analysis; Errors in Observations; ZB-splines; Orthogonal ZB-Splines
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Mathematical Geosciences (2025)
Online First (2024) DOI: 10.1007/s11004-024-10142-9
Cited 1 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39800
Development and Application of Scalable Density Functional Theory Machine Learning Models
Abstract
Electronic structure simulations allow researchers to compute fundamental properties of materials without the need for experimentation. As such, they routinely aid in propelling scientific advancements across materials science and chemical applications. Over the past decades, density functional theory (DFT) has emerged as the most popular technique for electronic structure simulations, due to its excellent balance between accuracy and computational cost. Yet, pressing societal and technological questions demand solutions for problems of ever-increasing complexity. Even the most efficient DFT implementations are no longer capable of providing answers in an adequate amount of time and with available computational resources. Thus, there is a growing interest in machine learning (ML) based approaches within the electronic structure community, aimed at providing models that replicate the predictive power of DFT at negligible cost. Within this work it will be shown that such ML-DFT approaches, up until now, do not succeed in fully encapsulating the level of electronic structure predictions DFT provides. Based on this assessment, a novel approach to ML-DFT models is presented within this thesis. An exhaustive framework for training ML-DFT models based on a local representation of the electronic structure is developed, including minute treatment of technical issues such as data generation techniques and hyperparameter optimization strategies. Models found via this framework recover the wide array of predictive capabilities of DFT simulations at drastically reduced cost, while retaining DFT levels of accuracy. It is further demonstrated how such models can be used across differently sized atomic systems, phase boundaries and temperature ranges, underlining the general usefulness of this approach.
Keywords: Density Functional Theory; Machine Learning; Surrogate Model
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LDOS/SNAP data for MALA: Beryllium at 298K
ROBIS: 35016 HZDR-primary research data are used by this (Id 39797) publication -
Scripts and models for "Machine learning the electronic structure of matter …
ROBIS: 36845 HZDR-primary research data are used by this (Id 39797) publication -
Data and Scripts for "Accelerating Equilibration in First-Principles Molecular …
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LDOS/SNAP data for MALA: Aluminium at 298K and 933K
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LDOS/SNAP data for MALA: Beryllium at high temperatures
ROBIS: 36846 HZDR-primary research data are used by this (Id 39797) publication -
Scripts and Models for "Predicting electronic structures at any length scale …
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Retrained Models and Scripts for Aluminum at 298K and 933K
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Dataset and scripts for A Deep Dive into Machine Learning Density Functional …
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Scripts and Models for "Predicting electronic structures at any length scale …
RODARE: 1851 HZDR-primary research data are used by this (Id 39797) publication -
LDOS/SNAP data for MALA: Beryllium at 298K
RODARE: 1834 HZDR-primary research data are used by this (Id 39797) publication -
Retrained Models and Scripts for Aluminum at 298K and 933K
RODARE: 2725 HZDR-primary research data are used by this (Id 39797) publication -
Data and Scripts for "Accelerating Equilibration in First-Principles Molecular …
RODARE: 1856 HZDR-primary research data are used by this (Id 39797) publication -
LDOS/SNAP data for MALA: Aluminium at 298K and 933K
RODARE: 2485 HZDR-primary research data are used by this (Id 39797) publication -
LDOS/SNAP data for MALA: Beryllium at high temperatures
RODARE: 2268 HZDR-primary research data are used by this (Id 39797) publication -
Scripts and models for "Machine learning the electronic structure of matter …
RODARE: 2266 HZDR-primary research data are used by this (Id 39797) publication -
Dataset and scripts for A Deep Dive into Machine Learning Density Functional …
RODARE: 1294 HZDR-primary research data are used by this (Id 39797) publication
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Doctoral thesis
TU Dresden, 2024
Mentor: Prof. Dr. Thomas Cowan, Dr. Attila Cangi
199 Seiten
Permalink: https://www.hzdr.de/publications/Publ-39797
Ionization potential depression and charge state of warm dense hydrogen from ab initio path integral Monte Carlo simulations
Bellenbaum, H.; Schwalbe, S.; Gawne, T. D.; Vorberger, J.; Fletcher, L.; Böhme, M.; Moldabekov, Z.; Chapman, D.; Doeppner, T.; Bonitz, M.; Dornheim, T.
Abstract
Research into Warm Dense Matter (WDM) has become more important with recent advances in inertial confinement fusion and astrophysics. The interplay between quantum degeneracy and Coulomb interactions, and the transition of condensed and plasma phases occurring under these conditions, however, make WDM extremely difficult to describe theoretically. Several methods exist to describe matter at these conditions, with recent extensions to Path Integral Monte Carlo (PIMC) allowing the calculation of the Laplace transform of the dynamic structure factor, i.e. the imaginary time correlation function (ITCF), of warm dense hydrogen [1]. While PIMC is quasi-exact, it does not give access to other important physical quantities describing a plasma state, like the ionisation and ionisation potential depression (IPD). Moreover, both are difficult to measure experimentally. To remedy this, we instead compare the ITCF from PIMC simulations with synthetic X-Ray Thomson Scattering spectra [2], computed from a Chihara decomposition [3], to obtain a best estimate for the ionisation state. The IPD is then directly calculated using the Saha equation and compared against other commonly used models. We expect this work to be relevant for future inertial confinement energy developments, particularly in validating equation of state models, and for the refinement of astrophysical models.
[1] T. Dornheim et.al., arXiv preprint arXiv:2403.08570 (2024)
[2] T. Dornheim et.al., Phys. Plasmas 30, 042707 (2023)
[3] G. Gregori et.al., Phys. Rev. E 67, 026412 (2003)
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Lecture (Conference)
66th Annual Meeting of the APS Division of Plasma Physics, 07.-11.10.2024, Atlanta, USA
Permalink: https://www.hzdr.de/publications/Publ-39790
Data publication: Real-time 3D Particle Tracking using Ultrafast Electron Beam X-ray Computed Tomography
Windisch, D.; Barthel, F.; Bieberle, A.; Hampel, U.
Abstract
This dataset includes all raw data used in the linked publication "Real-time 3D Particle Tracking using Ultrafast Electron Beam X-ray Computed Tomography".
Keywords: Particle tracking; ultrafast X-ray imaging; real-time control
Involved research facilities
- ROFEX
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-22 Open access
DOI: 10.14278/rodare.3219
Versions: 10.14278/rodare.3220
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39785
Integration of Python WebApps into the Draco Laser Shot Tracking Pipeline, and Provision of Data and Metadata in the HZDR Data Patchwork
Tippey, K. E.; Knodel, O.; Schlenvoigt, H.; Kluge, T.; Pape, D.; Gruber, T.; Müller, S.; Juckeland, G.
Abstract
The HZDR team has harnessed the power of Python, Flask, Dash, ZeroMQ and Kafka in tandem with MongoDB, to create a suite of web-based applications that simplify the extraction of laser shot data and metadata from various distinct, heterogeneous, semi-automated data acquisition systems.
The Shotsheet apps play a central role in manual logging, especially in a facility with highly flexible but manual operation modes. These apps also connect to other data sources like the Mediawiki ELN system. To enable further automation, we’ve developed the Experimental Shot Counter and enrichment app (escape), which handles incoming ZeroMQ messages from the Draco Laser system (experiment driver) and provides tailored ZeroMQ and Kafka messages within the Lab intranet. These messages can automate the readout and processing of measurements, as well as trigger mechanical actions.
In the subsequent landscape of data management, navigating the diverse array of metadata catalogs – such as SciCat, data publications on Invenio derivatives, and internal archives – presents a formidable challenge. However, with the right strategies, this mosaic of data can be effectively combined and represented to unlock its full potential. In the HZDR data management ecosystem , we delve into the intricacies of data fusion, exploring innovative approaches to seamlessly harmonize metadata catalogs, data publications, and archives.
Keywords: Python; Flask; HZDR
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Contribution to proceedings
DAPHNE Annual Meeting 2024, 11.-13.03.2024, Dresden, Germany
Proceedings of DAPHNE Annual Meeting 2024
Permalink: https://www.hzdr.de/publications/Publ-39784
Relaxation to persistent currents in a Hubbard trimer coupled to fermionic baths
Szpak, N.; Schaller, G.; Schützhold, R.; König, J.
Abstract
We consider a ring of fermionic quantum sites, modeled by the Fermi-Hubbard Hamiltonian, in which electrons can move and interact strongly via the Coulomb repulsion. The system is coupled to fermionic cold baths, which by the exchange of particles and energy induce relaxation in the system. We eliminate the
environment and describe the system effectively by Lindblad master equations in various versions valid for different coupling parameter regimes. The early relaxation phase proceeds in a universal way, irrespective of the relative couplings and approximations. The system settles down to its low-energy sector and is consecutively well approximated by the Heisenberg model. We compare different Lindblad approaches, which, in the late relaxation, push the system towards different final states with opposite, extreme spin orders, from ferromagenetic to antiferromagnetic. Due to spin frustration in the trimer (a three site ring), degenerate ground states are formed by spin waves (magnons). The system described by the global coherent version of the Lindblad operators relaxes
towards the final states carrying directed persistent spin currents. We numerically confirm these predictions.
Keywords: Lindblad equation; Fermi-Hubbard Hamiltonian; relaxation dynamics; Heisenberg model; coherent approximation
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Physical Review B 110(2024), 115131
DOI: 10.1103/PhysRevB.110.115131
Downloads
- Open Access Version from arxiv.org
- Secondary publication expected from 17.09.2025
Permalink: https://www.hzdr.de/publications/Publ-39778
Julia in high-energy physics: A paradigm shift or just another tool?
Abstract
The Julia programming language was designed for scientific computing and with its claimed usability („walks like Python“) and speed („runs like C“), it seems to be a scientists‘ software dream come true. Julia appears to be particularly well-suited for high-energy physics (HEP), where reliable software tools and rapid development cycles are crucial for everyday work. Whether it’s data processing, or the simulation of the whole experiment, or the final data analysis and interactive visualization, the Julia ecosystem — with over ten thousand packages — might be a modern and high-performance software solution and the right set of tools to easily build any missing pieces.
In this talk, we will discuss, if the Julia programming language meets these requirements and can withstand testing on the workbenches of HEP. Additionally, we give an overview of current contributions in Julia to the HEP-related software stack and its potential trajectory. Moreover, we explore how the software development process itself can benefit from Julia, as it strikes an ideal balance between high-performance technology and student-friendly training — an especially valuable combination for the rapidly moving high-energy physics community.
Keywords: Julia Programming Language; High-Energy Physics; HPC
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Invited lecture (Conferences)
JuliaHEP 2024 Workshop, 30.09.-04.10.2024, CERN, Switzerland
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39776
CT image sequences of sandwich packings: B1-250 plus B1-750 at constant liquid rate of 50 m³/(m²h) and various gas rates
Sohr, J.; Barthel, F.; Sprewitz, U.; Schubert, M.
Producer: Barthel, Frank; DataManager: Sprewitz, Uwe; Researcher: Sohr, Johanna; Project Leader: Schubert, Markus; DataCurator: Bieberle, André
Abstract
This repository contains sequences of CT images of the two-phase flow in sandwich packings that are alternately arranged in a packing stack using B1-250 (specific geometric surface area is 250 m² /m³) for de-entrainment layer and B1-750 (specific geometric surface area is 750 m² /m³) for holdup layer. As measurement system the ultrafast electron beam X-ray computed tomography scanner was applied in dual plane scanning mode with a dual-imaging frequency of 1000 Hz. Operating parameters, the scanning plane as well as the tags "AB" for de-entrainment layer, "AN" for hold-up layer and "DRIVE" for an axial scan are encoded in the name of the data files.
Keywords: sandwich packings; two-phase flow; ultrafast electron-beam X-ray CT
Involved research facilities
- TOPFLOW Facility
- ROFEX
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-18 Restricted access
DOI: 10.14278/rodare.3207
Versions: 10.14278/rodare.3208
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39769
CT image sequences of sandwich packings: B1-250 plus B1-750 at constant liquid rate of 20 m³/(m²h) and various gas rates
Sohr, J.; Barthel, F.; Sprewitz, U.; Schubert, M.
Producer: Barthel, Frank; DataManager: Sprewitz, Uwe; Researcher: Sohr, Johanna; Project Leader: Schubert, Markus; DataCurator: Bieberle, André
Abstract
This repository contains sequences of CT images of the two-phase flow in sandwich packings that are alternately arranged in a packing stack using B1-250 (specific geometric surface area is 250 m² /m³) for de-entrainment layer and B1-750 (specific geometric surface area is 750 m² /m³) for holdup layer. As measurement system the ultrafast electron beam X-ray computed tomography scanner was applied in dual plane scanning mode with a dual-imaging frequency of 1000 Hz. Operating parameters, the scanning plane as well as the tags "AB" for de-entrainment layer, "AN" for hold-up layer and "DRIVE" for an axial scan are encoded in the name of the data files.
Keywords: sandwich packings; two-phase flow; ultrafast electron-beam X-ray CT
Involved research facilities
- TOPFLOW Facility
- ROFEX
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-18 Restricted access
DOI: 10.14278/rodare.3205
Versions: 10.14278/rodare.3206
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Permalink: https://www.hzdr.de/publications/Publ-39768
Structural and Compositional Optimization of Bimetallic NiCo Nanoalloys for Promotion of Alkaline Hydrogen Evolution Reaction
Mohanty, B.; Pradhan, L.; Satpati, B.; Rajput, P.; Ghorbani Asl, M.; Wei, Y.; Menezes, P. W.; Krasheninnikov, A.; Kumar Jenaa., B.
Abstract
Alkaline hydrogen evolution reaction (HER) is highly desired due to its economic utility as well as its basic significance in the study of all electrocatalytic processes taking place on cathode electrodes. Herein, we report the nickel and cobalt-based bimetallic alloy nanoparticles embedded in nitrogen-doped carbon (NiₓCo₁₋ₓ@NC) starting from novel metal-organic complexes. Among the synthesized alloy nanoparticle catalysts, Ni₁Co₃@NC exhibits the best performance for HER, reaching a current density of 10 mA/cm² merely at an overpotential of 28 mV, outperforming state-of-the-art noble Pt-based, as well as non-noble metal-based catalysts. Remarkably, this catalyst displays a high turnover frequency (TOF) of 32.44 s⁻¹ and even long-term durability at higher current density (50 mA/cm²) up to 175 hours with negligible decay. A series of advanced characterizations reveal that Ni₁Co₃@NC undergoes minimal near-surface restructuring, majorly retaining its structure during longer operations. In order to comprehend the interaction between the inherent HER activity and the metal center, we conducted further experiments for several bimetallic alloy nanoparticles by alloying Co nanoparticles with Mn, Fe, and Zn. This work sheds important light on the structure-function link for bimetallic alloy nanoparticles made of non-noble metals that exhibit electrocatalytic HER activity in an alkaline medium.
Keywords: Bimetallic alloy nanoparticles; NiCo; Alkaline solutions; Hydrogen evolution reaction; Improved hydrogen adsorption
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39767) publication
- Journal of Power Sources (2024)
Permalink: https://www.hzdr.de/publications/Publ-39767
CT image sequences of sandwich packings: B1-250 plus B1-750 at constant liquid rate of 10 m³/(m²h) and various gas rates
Sohr, J.; Barthel, F.; Sprewitz, U.; Schubert, M.
Producer: Barthel, Frank; DataManager: Sprewitz, Uwe; Researcher: Sohr, Johanna; Project Leader: Schubert, Markus; DataCurator: Bieberle, André
Abstract
This repository contains sequences of CT images of the two-phase flow in sandwich packings that are alternately arranged in a packing stack using B1-250 (specific geometric surface area is 250 m² /m³) for de-entrainment layer and B1-750 (specific geometric surface area is 750 m² /m³) for holdup layer. As measurement system the ultrafast electron beam X-ray computed tomography scanner was applied in dual plane scanning mode with a dual-imaging frequency of 1000 Hz. Operating parameters, the scanning plane as well as the tags "AB" for de-entrainment layer, "AN" for hold-up layer and "DRIVE" for an axial scan are encoded in the name of the data files.
Keywords: sandwich packings; two-phase flow; ultrafast electron-beam X-ray CT
Involved research facilities
- TOPFLOW Facility
- ROFEX
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-21 Restricted access
DOI: 10.14278/rodare.3203
Versions: 10.14278/rodare.3204
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39766
Setting reaction of a olivine-based Mg-phosphate cement
Bernasconi, D.; Viani, A.; Zárybnická, L.; Bordignon, S.; da Assuncao Godinho, J. R.; Maximenko, A.; Celikutku, C.; Jafri, S. F.; Borfecchia, E.; Wehrung, Q.; Gobetto, R.; Pavese, A.
Abstract
The cementitious properties of natural Mg-rich olivine when reacted with a phosphoric acid solution are investigated, as a function of acid concentration and liquid/solid mass ratio. The obtained cements are composed of residual olivine crystals and amorphous silica nanoparticles dispersed in a dense and compact newberyite (MgHPO4∙3H2O) matrix. The latter was mostly formed by packed micrometric tabular crystals, although evidence of the presence of a fraction of amorphous MgHPO4 was also found. Water content in the raw mix was observed to play a pivotal role on the reaction pathway, either promoting porosity or hindering the crystallization of the products. Up to 57 % of olivine reactivity, whose dissolution was promoted by the curing temperature (60 °C) and low pH, was achieved. All in all, these results indicate that the industrial mineral olivine may serve a viable source of Mg for the production of phosphate cements.
Keywords: Phosphate cement; Magnesium cement; Olivine; Alternative binders
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Cement and Concrete Research 186(2024), 107694
DOI: 10.1016/j.cemconres.2024.107694
Permalink: https://www.hzdr.de/publications/Publ-39763
Comprehensive Synthesis and Structural Trends in Tetramethyl Diglycolamide (TMDGA) Nitrate Complexes with Lanthanides and Americium
Rotermund, B. M.; Beck, N. B.; Sperling, J. M.; Horne, G. P.; Huffman, Z. K.; Grödler, D.; Albrecht, T. E.
Abstract
Complexes of N,N,N′,N′-tetramethyl diglycolamide (TMDGA), a hydrophilic diglycolamide (DGA) proposed as an aqueous phase holdback reagent, have been crystallizedfor the majority of the lanthanide series (excluding promethium), yttrium, and americium to deepen our structural understanding of trivalent metal ion (M³⁺) DGA coordination compounds in the presence of nitrate counter-anions. The presented collection of 16 complexes with accompanying single-crystal structures, taking formulas M(TMDGA)₃][M(NO₃)₆] (M = La, Ce, Pr, Nd, Sm, Am), [M(TMDGA)₃][M(NO₃)₅(H₂O)]₁₋ₓ[M(NO₃)₄(H₂O)₂]ₓ(NO₃)₁₊ₓ (M = Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb), [M(TMDGA)₃]₂[M(NO₃)₄(H₂O)₂]₀.₇₅[M(NO₃)₅(H₂O)]₁.₂₅(NO₃)₂.₇₅·H₂O (M = Lu), and [M(TMDGA)₃][M(NO₃)₅(H₂O); whereas the remaining smaller lanthanides did not possess sufficiently large ionic radii to coordinate six bidentate nitrate anions, instead, one or two nitrate anions are situated in the outer sphere. The systematic progression of changes in the anionic environments of these complexes outlines the changing coordination habits afforded by the lanthanide contraction.
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Crystal Growth & Design (2024)
DOI: 10.1021/acs.cgd.4c00869
Permalink: https://www.hzdr.de/publications/Publ-39761
Dynamic convergent shock compression initiated by return current in high-intensity laser–solid interactions
Yang, L.; Rehwald, M.; Kluge, T.; Laso García, A.; Toncian, T.; Zeil, K.; Schramm, U.; Cowan, T.; Huang, L.
Abstract
We investigate the dynamics of convergent shock compression in solid cylindrical targets irradiated by an ultrafast relativistic laser pulse. Our particle-in-cell simulations and coupled hydrodynamic simulations reveal that the compression process is initiated by both magnetic pressure and surface ablation associated with a strong transient surface return current with density of the order of 1017 A/m2 and lifetime of 100 fs. The results show that the dominant compression mechanism is governed by the plasma β, i.e., the ratio of thermal pressure to magnetic pressure. For targets with small radius and low atomic number Z, the magnetic pressure is the dominant shock compression mechanism. According to a scaling law, as the target radius and Z increase, the surface ablation pressure becomes the main mechanism generating convergent shocks. Furthermore, an indirect experimental indication of shocked hydrogen compression is provided by optical shadowgraphy measurements of the evolution of the plasma expansion diameter. The results presented here provide a novel basis for the generation of extremely high pressures exceeding Gbar (100 TPa) to enable the investigation of high-pressure physics using femtosecond J-level laser pulses, offering an alternative to nanosecond kJ-laser pulse-driven and pulsed power Z-pinch compression methods.
Involved research facilities
- HIBEF
- Draco
-
Matter and Radiation at Extremes 9(2024), 047204
DOI: 10.1063/5.0181321
Cited 1 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39759
Calculations and Measurements of the Neutron Fluence outside the RPV for the Decommissioning of a PWR
Rachamin, R.; Konheiser, J.; Barkleit, A.; Nikitin, E.; Seidl, M.
Abstract
Determining the neutron activation in the single components is an important task in the
decommissioning process of NPPs. Therefore, neutron fluences are the most fundamental and important
parameter on which every decommissioning planning is based. The aim of this study is to estimate this
accurately using Monte Carlo simulations. A detailed 3D model of a PWR was developed, and the
neutron fluence was calculated and validated based on metal foil-activation measurements.
Keywords: PWR; Decommissioning; Neutron fluence; Monte Carlo; Activation foils
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Contribution to proceedings
GLOBAL 2024 International Conference on Nuclear Fuel Cycle, 06.10.2024, Tokyo, Japan -
Poster
GLOBAL 2024 International Conference on Nuclear Fuel Cycle, 07.10.2024, Tokyo, Japan
Permalink: https://www.hzdr.de/publications/Publ-39752
Development and application of Serpent/DYN3D/ATHLET code system for SFR safety analysis
Ponomarev, A.; Nikitin, E.; Fridman, E.
Abstract
The paper presents the current status and recent applications of the Serpent/DYN3D/ATHLET code system to various Sodium-cooled Fast Reactor (SFR) designs. It emphasizes the system’s capability for coupled DYN3D and ATHLET transient simulations that account for all significant reactivity effects inherent to SFR, in particular those related to thermal expansion of core and primary system structural elements. Recent applications to transient analysis across SFRs of various sizes and power outputs demonstrates robustness of the implemented approaches and provides a solid validation basis for the developed methodology.
Keywords: SFR; safety analysis; Unprotected-Loss-Of-Flow; coupled neutronic/thermal hydraulic simulation; spatial kinetics; core thermal expansion
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Contribution to proceedings
GLOBAL 2024 International Conference on Nuclear Fuel Cycle, 06.10.2024, Tokyo, Japan -
Lecture (Conference)
GLOBAL 2024 International Conference on Nuclear Fuel Cycle, 08.10.2024, Tokyo, Japan
Permalink: https://www.hzdr.de/publications/Publ-39750
Growth of Ba2CoWO6 single crystals and their magnetic, thermodynamic and electronic properties
Hanna, A. R. N.; Islam, A. T. M. N.; Ritter, C.; Luther, S.; Feyerherm, R.; Lake, B.
Abstract
This study explores the bulk crystal growth, structural characterization, and physical property measurements of the cubic double perovskite Ba2CoWO6 (BCWO). In BCWO, Co2+ ions form a face-centred cubic lattice with non-distorted cobalt octahedra. The compound exhibits long-range antiferromagnetic order below TN = 14 K. Magnetization data indicated a slight anisotropy along with a spin-flop transition at 10 kOe, a saturation field of 310 kOe and an ordered moment of 2.17 μB at T = 1.6 K. Heat capacity measurements indicate an effective j = 1/2 ground state configuration, resulting from the combined effects of the crystal electric field and spin-orbit interaction. Surface photovoltage analysis reveals two optical gaps in the UV–Visible region, suggesting potential applications in photocatalysis and photovoltaics. The magnetic and optical properties highlight the significant role of orbital contributions within BCWO, indicating various other potential applications.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Journal of Physics: Condensed Matter 36(2024), 505801
DOI: 10.1088/1361-648X/ad7770
Permalink: https://www.hzdr.de/publications/Publ-39748
Dramatic elastic response at the critical end point in UTe2
Valiska, M.; Haidamak, T.; Cabala, A.; Pospisil, J.; Bastien, G.; Sechovsky, V.; Prokleska, J.; Yanagisawa, T.; Opletal, P.; Sakai, H.; Haga, Y.; Miyata, A.; Gorbunov, D.; Zherlitsyn, S.
Abstract
The first-order transition line in the H-T phase diagram of itinerant electron metamagnets terminates at the critical end point—analogous to the critical point on the gas-liquid condensation line in the p-T phase diagram. To unravel the impact of critical magnetic fluctuations on the crystal lattice of a metamagnet at the critical end point, we performed an ultrasonic study of the itinerant electron metamagnet UTe2 across varying temperatures and magnetic fields. At temperatures exceeding 9 K, a distinct V-shaped anomaly emerges, precisely centered at the critical field of the metamagnetic transition in the isothermal field dependence of elastic constants. This anomaly arises from lattice instability, triggered by critical magnetic fluctuations via strong magnetoelastic interactions. Remarkably, this effect is maximized precisely at the critical-end-point temperature. Comparative measurements of another itinerant metamagnet, UCoAl, reveal intriguing commonalities. Despite significant differences in the paramagnetic ground state, lattice symmetry, and the expected metamagnetic transition process between UTe2 and UCoAl, both exhibit similar anomalies in elastic properties near the critical end point.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review Materials 8(2024), 094415
DOI: 10.1103/PhysRevMaterials.8.094415
Permalink: https://www.hzdr.de/publications/Publ-39747
Giant magnetocaloric effect in a rare-earth-free layered coordination polymer at liquid hydrogen temperatures
Levinsky, J. J. B.; Beckmann, B.; Gottschall, T.; Koch, D.; Ahmadi, M.; Gutfleisch, O.; Blacke, G. R.
Abstract
Magnetic refrigeration, which utilizes the magnetocaloric effect, can provide a viable alternative to the ubiquitous vapor compression or Joule-Thompson expansion methods of refrigeration. For applications such as hydrogen gas liquefaction, the development of magnetocaloric materials that perform well in moderate magnetic fields without using rare-earth elements is highly desirable. Here we present a thorough investigation of the structural and magnetocaloric properties of a novel layered organic-inorganic hybrid coordination polymer Co4(OH)6(SO4)2[enH2] (enH2 = ethylenediammonium). Heat capacity, magnetometry and direct adiabatic temperature change measurements using pulsed magnetic fields reveal a field-dependent ferromagnetic second-order phase transition at 10 K < TC < 15 K. Near the hydrogen liquefaction temperature and in a magnetic field change of 1 T, a large maximum value of the magnetic entropy change, ΔSPk
M = − 6.31 J kg−1 K−1, and an adiabatic temperature change, ΔTad = 1.98K, areobserved. These values are exceptional for rare-earth-free materials and competitive with many rare-earth-containing alloys that have been proposed for magnetic cooling around the hydrogen liquefaction range.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
-
Nature Communications 15(2024), 8559
DOI: 10.1038/s41467-024-52837-x
Permalink: https://www.hzdr.de/publications/Publ-39746
Interface Dependent Coexistence of Two-Dimensional Electron and Hole Gases in Mn-doped InAs/GaSb
Riney, L.; Bac, S.-K.; Zhukovskyi, M.; Orlova, T.; Fields, S. S.; Wang, J.; Kotte, T.; Graf, D.; Bennett, S. P.; Liu, X.; Assaf, B. A.
Abstract
The interface of common III-V semiconductors InAs and GaSb can be utilized to realize a two-dimensional (2D) topological insulator state. The 2D electronic gas at this interface can yield Hall quantization from coexisting electrons and holes. This anomaly is a determining factor in the fundamental origin of the topological state in InAs/GaSb. Here, the coexistence of electrons and holes in InAs/GaSb is tied to the chemical sharpness of the interface. Magnetotransport, in samples of Mn-doped InAs/GaSb cleaved from wafers grown at a spatially inhomogeneous substrate temperature, is studied. It is reported that the observation of quantum oscillations and a quantized Hall effect whose behavior, exhibiting coexisting electrons and holes, is tuned by this spatial nonuniformity. Through transmission electron microscopy measurements, it is additionally found that samples that host this co-existence exhibit a chemical intermixing between group III and group V atoms that extends over a larger thickness about the interface. The issue of intermixing at the interface is systematically overlooked in electronic transport studies of topological InAs/GaSb. These findings address this gap in knowledge and shed important light on the origin of the anomalous behavior of quantum oscillations seen in this 2D topological insulator.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Advanced Materials Interfaces (2024)2024, 2400630
DOI: 10.1002/admi.202400630
Permalink: https://www.hzdr.de/publications/Publ-39745
Structural Regulation of Au-Pt Bimetallic Aerogels for Catalyzing the Glucose Cascade Reaction
Wang, C.; Wang, L.; Nallathambi, V.; Liu, Y.; Kresse, J.; Hübner, R.; Reichenberger, S.; Gault, B.; Zhan, J.; Eychmüller, A.; Cai, B.
Abstract
Bimetallic nanostructures are promising candidates for the development of enzyme-mimics, yet the deciphering of the structural impact on their catalytic properties poses significant challenges. By leveraging the structural versatility of nanocrystal aerogels, this study reports a precise control of Au-Pt bimetallic structures in three representative structural configurations, including segregated, alloy, and core-shell structures. Benefiting from a synergistic effect, these bimetallic aerogels demonstrate improved peroxidase- and glucose oxidase-like catalytic performances compared to their monometallic counterparts, unleashing tremendous potential in catalyzing the glucose cascade reaction. Notably, the segregated Au-Pt aerogel shows optimal catalytic activity, which is 2.80 and 3.35 times higher than that of the alloy and core-shell variants, respectively. This enhanced activity is attributed to the high-density Au-Pt interface boundaries within the segregated structure, which foster greater substrate affinity and superior catalytic efficiency. This work not only sheds light on the structure-property relationship of bimetallic catalysts but also broadens the application scope of aerogels in biosensing and biological detections.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39744) publication
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Advanced Materials 36(2024), 2405200
DOI: 10.1002/adma.202405200
Permalink: https://www.hzdr.de/publications/Publ-39744
Data publication: Simulation results on Aminophenyl Viologen
Mitrofanov, A.; Dreimann, O.; Zakirova, K.; Waentig, A. L.; Wrzesińska-Lashkova, A.; Kuc, A. B.; Ruck, M.; Vaynzof, Y.; Feng, X.; Voit, B.
Abstract
Structural and electronic properties simulated using DFT/PBE level of theory with TS dispersion correction as implemented in FHI-Aims code.
Related publications
- DOI: 10.1021/acs.inorgchem.4c01711 references this (Id 39743) publication
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Narrow Bandgap 1D Lead Iodide Perovskite with Aminophenyl Viologen
ROBIS: 39027 has used this (Id 39743) publication of HZDR-primary research data
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-07-26 Open access
DOI: 10.14278/rodare.3197
Versions: 10.14278/rodare.3198
License: CC-BY-4.0
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39743
Paratellurite Nanowires as a Versatile Material for THz Phonon Polaritons
Mayer, R. A.; Wehmeier, L.; Torquato, M.; Chen, X.; Feres, F. H.; Maia, F. C. B.; Obst, M.; Kaps, F. G.; Luferau, A.; Klopf, J. M.; Gilbert Corder, S. N.; Bechtel, H. A.; González, J. C.; Viana, E. R.; Eng, L. M.; Kehr, S. C.; Freitas, R. O.; Barcelos, I. D.
Abstract
Polaritons, i.e., hybrid quasi-particles of light and matter resonances, have been extensively investigated due to their potential to enhance light–matter interactions. Although polaritonic applications thrive in the mid-infrared range, their extension to the terahertz (THz) range remains limited. Here, we present paratellurite (α-TeO2) nanowires, a versatile material acting as a platform for different types of phonon polaritons. Utilizing synchrotron infrared nanospectroscopy from 10 to 24 THz, we uncover the polaritonic properties of α-TeO2 nanowires, showcasing their dual functionality as both a Fabry–Pérot cavity and a waveguide for surface phonon polaritons. Furthermore, near-field measurements with a free-electron laser as a THz source reveal a localized optical contrast down to 5.5 THz, an indication of hyperbolic bands. Our findings complement the repertoire of polaritonic materials, with significant implications for advancing THz technologies.
Keywords: s-SNOM; FEL; THz; near-field; polariton; nanoscopy; phonons
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- F-ELBE
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 39742) publication
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ACS Photonics 11(2024)10, 4323-4333
DOI: 10.1021/acsphotonics.4c01249
Downloads
- Secondary publication expected from 20.09.2025
Permalink: https://www.hzdr.de/publications/Publ-39742
Ultrafast switching of trions in 2D materials by terahertz photons
Venanzi., T.; Cuccu, M.; Perea-Causin, R.; Sun, X.; Samuel, B.; Erkensten, D.; Taniguchi., T.; Watanabe., K.; Malic., E.; Helm, M.; Winnerl, S.; Chernikovon, A.
Abstract
External control of optical excitations is key for manipulating light–matter coupling and is highly desirable for photonic technologies. Excitons in monolayer semiconductors emerged as a unique nanoscale platform in this context, offering strong light–matter coupling, spin–valley locking and exceptional tunability. Crucially, they allow electrical switching of their
optical response due to efficient interactions of excitonic emitters with free charge carriers, forming new quasiparticles known as trions and Fermi polarons. However, there are major limitations to how fast the light emission of these states can be tuned, restricting the majority of applications to an essentially static regime. Here we demonstrate switching of excitonic light
emitters in monolayer semiconductors on ultrafast picosecond time scales by applying short pulses in the terahertz spectral range following optical injection. The process is based on a rapid conversion of trions to excitons by absorption of terahertz photons inducing photo detachment. Monitoring time-resolved emission dynamics in optical-pump/terahertz-push
experiments, we achieve the required resonance conditions as well as demonstrate tunability of the process with delay time and terahertz pulse power. Our results introduce a versatile experimental tool for fundamental research of light-emitting excitations of composite Bose–Fermi mixtures and open up pathways towards technological developments of new types of nanophotonic device based on atomically thin materials.
Involved research facilities
- F-ELBE
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Nature Photonics (2024)
DOI: 10.1038/s41566-024-01512-0
Downloads
- Secondary publication expected from 23.09.2025
Permalink: https://www.hzdr.de/publications/Publ-39741
Curvilinear magnetism: fundamentals and applications
Abstract
Curvilinear magnetism is a framework, which helps understanding the impact of geometric curvature on complex magnetic responses of curved 1D wires and 2D shells [1-3]. This approach provides means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape of magnetic thin films and nanowires [3]. In this talk, we will address fundamentals of curvature-induced effects in magnetism and review the envisioned application scenarios. In particular, we will demonstrate that curvature allows tailoring fundamental anisotropic and chiral magnetic interactions and enables fundamentally new nonlocal chiral symmetry breaking effect [4]. The topology of the geometry of 3D shaped magnetic objects allows stabilizing multiple solitons within a confined nanoarchitecture [5]. Those are relevant for numerous research and technology fields ranging from non-conventional computing and spin-wave splitters for low-energy magnonics. The application potential of geometrically curved magnetic architectures is being explored as mechanically reshapeable magnetic field sensors for automotive applications, spin-wave filters, high-speed racetrack memory devices, magnetic soft robots [6] as well as on-skin interactive electronics relying on thin films [7-9] as well as printed magnetic composites [10,11] with appealing self-healing performance [12]. This opens perspectives for magnetoelectronics in smart wearables, interactive printed electronics and motivates further explorations towards the realization of eco-sustainable magnetic field sensing relying on biocompatible and biodegradable materials [13-15].
[1] P. Gentile et al., Electronic materials with nanoscale curved geometries. Nature Electronics (Review) 5, 551 (2022).
[2] P. Makushko et al., A tunable room-temperature nonlinear Hall effect in elemental bismuth thin films. Nature Electronics 7, 207 (2024).
[3] D. Makarov et al., New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. Advanced Materials (Review) 34, 2101758 (2022).
[4] O. M. Volkov et al., Chirality coupling in topological magnetic textures with multiple magnetochiral parameters. Nature Communications 14, 1491 (2023).
[5] O. Volkov et al., Three-dimensional magnetic nanotextures with high-order vorticity in soft magnetic wireframes. Nature Communications 15, 2193 (2024).
[6] M. Ha et al., Reconfigurable Magnetic Origami Actuators with On-Board Sensing for Guided Assembly. Advanced Materials 33, 2008751 (2021).
[7] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Advanced Functional Materials (Review) 31, 2007788 (2021).
[8] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[9] G. S. Canon Bermudez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoception and interactive electronics. Nature Electronics 1, 589 (2018).
[10] M. Ha et al., Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-Conformal Electronics. Advanced Materials 33, 2005521 (2021).
[11] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Advanced Materials Technologies 7, 2200227 (2022).
[12] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).
[13] X. Wang et al., Printed magnetoresistive sensors for recyclable magnetoelectronics. J. Mater. Chem. A 12, 24906 (2024).
[14] E. S. Oliveros Mata et al., Magnetically aware actuating composites: Sensing features as inspiration for the next step in advanced magnetic soft robotics. Phys. Rev. Appl. (Review) 20, 060501 (2023).
[15] L. Guo et al., Printable magnetoresistive sensors: A crucial step toward unconventional magnetoelectronics. Chinese Journal of Structural Chemistry (Review) 100428 (2024).
Keywords: curvilinear magnetism; shapeable magnetoelectronics; printed magnetoelectronics; magnetic composites
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39740) publication
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Lecture (others)
Seminar of the Department of Materials Science, 17.10.2024, Shanghai, China
Permalink: https://www.hzdr.de/publications/Publ-39740
Probing CLFV with the Mu2e Experiment at Fermilab
Abstract
Presentation at "International Workshop on Baryon and Lepton Number Violation", Karlsruhe (Germany), Ovtober 8-11, 2024
Keywords: Mu2e; CLFV; FNAL
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Invited lecture (Conferences)
International Workshop on Baryon and Lepton Number Violation, 08.-11.10.2024, Karlsruhe, Germany
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39739
Predicting the electronic structure of matter at scale with machine learning
Abstract
In this presentation, I will discuss our recent advancements in utilizing machine learning to significantly enhance the efficiency of electronic structure calculations [1]. Specifically, I will focus on our efforts to accelerate Kohn-Sham density functional theory calculations by incorporating deep neural networks within the Materials Learning Algorithms framework [2,3]. Our results demonstrate substantial gains in calculation speed for metals across their melting point. Additionally, our implementation of automated machine learning has resulted in significant savings in computational resources when identifying optimal neural network architectures, laying the foundation for large-scale investigations [4]. Furthermore, I will present our most recent breakthrough, which enables neural-network-driven electronic structure calculations for systems containing over 100,000 atoms [5]. This achievement opens up new avenues for studying complex materials systems that were previously computationally intractable.
[1] L. Fiedler, K. Shah, M. Bussmann, A. Cangi, Phys. Rev. Materials, 6, 040301 (2022)
[2] A. Cangi, J. A. Ellis, L. Fiedler, D. Kotik, N. A. Modine, V. Oles, G. A. Popoola, S. Rajamanickam, S. Schmerler, J. A. Stephens, A. P. Thompson, Phys. Rev. B 104, 035120 (2021).
[3] J. Ellis, L. Fiedler, G. Popoola, N. Modine, J. Stephens, A. Thompson, A. Cangi, S. Rajamanickam, Phys. Rev. B, 104, 035120 (2021)
[4] L. Fiedler, N. Hoffmann, P. Mohammed, G. Popoola, T. Yovell, V. Oles, J. Austin Ellis, S. Rajamanickam, A. Cangi, Mach. Learn.: Sci. Technol., 3, 045008 (2022)
[5] L. Fiedler, N. Modine, S. Schmerler, D. Vogel, G. Popoola, A. Thompson, S. Rajamanickam, A. Cangi, npj. Comput. Mater., 9, 115 (2023)
Keywords: Artificial intelligence; Machine learning; Neural networks; Deep learning; Electronic structure theory; Density functional theory; Materials science
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Invited lecture (Conferences)
Nano-Seminar, 17.10.2024, Dresden, Deutschland
PURL: https://nano.tu-dresden.de/seminar/2024_10_17_attila-cangi
Permalink: https://www.hzdr.de/publications/Publ-39737
Data Publication: Boron isotopic and mineral chemical composition in greisen-related Li-Fe micas at the Sadisdorf Li-Sn-(W-Cu) prospect, Erzgebirge, Germany: Pathways and mechanisms for hydrothermal lithium enrichment
Leopardi, D.; Gerdes, A.; Albert, R.; Krause, J.; Gutzmer, J.; Lehmann, B.; Burisch, M.
Abstract
Data set composed of sample descriptions, major and trace element compositions of micas, in-situ B isotopic analyses of micas and whole-rock B isotopic compositions of major lithologies at the Sadisdorf prospect.
Keywords: Li-Fe mica; Mineral geochemistry; B isotopes
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-11 Restricted access
DOI: 10.14278/rodare.3193
Versions: 10.14278/rodare.3194
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Permalink: https://www.hzdr.de/publications/Publ-39734
Pathway to industrial application of heterotrophic organisms in critical metals recycling from e-waste
Golzar-Ahmadi, M.; Bahaloo-Horeh, N.; Pourhossein, F.; Norouzi, F.; Schönberger, N.; Hintersatz, C.; Chakankar, M. V.; Holuszko, M.; Anna, H. K.
Abstract
The transition to renewable energies and electric vehicles has triggered an unprecedented demand for metals.
Sustainable development of these technologies relies on effectively managing the lifecycle of critical raw materials, including their responsible sourcing, efficient use, and recycling. Metal recycling from electronic waste
(e-waste) is of paramount importance owing to ore-exceeding amounts of critical elements and high toxicity of
heavy metals and organic pollutants in e-waste to the natural ecosystem and human body. Heterotrophic microbes secrete numerous metal-binding biomolecules such as organic acids, amino acids, cyanide, siderophores,
peptides, and biosurfactants which can be utilized for eco-friendly and profitable metal recycling. In this review
paper, we presented a critical review of heterotrophic organisms in biomining, and current barriers hampering
the industrial application of organic acid bioleaching and biocyanide leaching. We also discussed how these
challenges can be surmounted with simple methods (e.g., culture media optimization, separation of microbial
growth and metal extraction process) and state-of-the-art biological approaches (e.g., artificial microbial community, synthetic biology, metabolic engineering, advanced fermentation strategies, and biofilm engineering).
Lastly, we showcased emerging technologies (e.g., artificially synthesized peptides, siderophores, and biosurfactants) derived from heterotrophs with the potential for inexpensive, low-impact, selective and advanced
metal recovery from bioleaching solutions
Keywords: Critical metals; Recycling; Bioleaching; E-waste; Circular economy; Resource recovery
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Biotechnology Advances 77(2024), 108438
DOI: 10.1016/j.biotechadv.2024.108438
Permalink: https://www.hzdr.de/publications/Publ-39732
Trace element analysis and luminescence behavior of quartz in pegmatites of the Tørdal Region, Norway
Sittner, J.; Götze, J.; Müller, A.; Renno, A.; Ziegenrücker, R.; Pan, Y.
Abstract
This publication presents a study on the mineral chemistry and luminescence properties of quartz samples from pegmatites of the Tørdal region in Norway. A total of 12 samples were analyzed using Secondary Ion Mass Spectrometry (SIMS), Electron Paramagnetic Resonance Spectroscopy (EPR), and Cathodoluminescence (CL) to gain insights into their trace element concentration and distribution as well as their luminescence behavior. The samples are characterized by different Cl emissions at 450 nm, 500 nm 650 nm and an additional shoulder at 390 nm, which is only partially visible due to the absorption of the glass optics. Of these luminescence bands, the 500 nm band is the most dominant in most samples and it is characterized by an initial blue-green luminescence, which is not stable under electron irradiation. Moreover, it is characterized by a heterogeneous distribution within the samples. This luminescence can be mostly assigned to [AlO4/M+]0 defects, with charge compensation mostly achieved by Li+. Analyses by EPR spectroscopy prove the dominance of structurally bound Al, Li, and Ti ions in the investigated samples. Further analyses using SIMS mapping demonstrate that Na and K are mainly bound to micro fractures or inclusions, suggesting a limited role in the compensation of the luminescence centers. Additionally, the SIMS mappings show that some samples contain Al-rich clusters of 10 to 20 μm in diameter, whereas other trace elements are characterized by a homogeneous distribution. These clusters correspond to bright luminescence areas in size and shape and could potentially indicate H+ compensated [AlO4/M+]0 defects.
Keywords: Quartz; Trace elements; Cathodoluminescence; SIMS; EPR; Tørdal; Pegmatite
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Chemical Geology 670(2024), 122427
DOI: 10.1016/j.chemgeo.2024.122427
Permalink: https://www.hzdr.de/publications/Publ-39731
Immune modulatory microRNAs in tumors, their clinical relevance in diagnosis and therapy
Vaxevanis, C.; Bachmann, M.; Seliger, B.
Abstract
The importance of the immune system in regulating tumor growth by inducing immune cell-mediated cytotoxicity associated with patients’ outcomes has been highlighted in patients with cancer on treatment with different immunotherapeutics. However, tumors often escape immune surveillance, which is accomplished by different mechanisms. Recent studies demonstrated an essential role of small non-coding RNAs, such as microRNAs (miRNAs), in the post-transcriptional control of immune modulatory molecules. Multiple methods have been used to identify miRNAs targeting genes involved in escaping immune recognition including miRNAs targeting CTLA-4, PD-L1, HLA-G, components of the major histocompatibility class I antigen processing machinery (APM) as well as other immune response-relevant genes in tumors. Due to their function, these immune modulatory miRNAs can be used as (1) diagnostic and prognostic biomarkers allowing to discriminate between tumor stages and to predict the patients’ outcome as well as response and resistance to (immuno) therapies and as (2) therapeutic targets for the treatment of tumor patients. This review summarizes the role of miRNAs in tumor-mediated immune escape, discuss their potential as diagnostic, prognostic and predictive tools as well as their use as therapeutics including alternative application methods, such as chimeric antigen receptor T cells.
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Journal for ImmunoTherapy of Cancer 12(2024), e009774
DOI: 10.1136/jitc-2024-009774
Permalink: https://www.hzdr.de/publications/Publ-39729
Bridging the gap in electronic structure calculations via machine learning
Abstract
A highly efficient reconstruction method has been developed for the direct computation of Hamiltonian matrices in the atomic orbital basis from density functional theory calculations originally performed in the plane wave basis. This enables machine learning calculations of electronic structures on a large scale, which are otherwise not feasible with standard methods, and thus fills a methodological gap in terms of accessible length scales.
Keywords: Electronic structure structure; Density functional theory; Machine learning; Neural networks; Deep learning; Basis sets
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Nature Computational Science 4(2024), 729-730
DOI: 10.1038/s43588-024-00707-3
Permalink: https://www.hzdr.de/publications/Publ-39727
Characterizing Laser Transmission in the Relativistically Induced Transparency Regime for PW Laser-Driven Proton Acceleration
Umlandt, M. E. P.; Bernert, C.; Casati, G.; Cowan, T.; Dover, N. P.; Göthel, I.; Kiriyama, H.; Kluge, T.; Kon, A.; Kondo, K.; Kroll, F.; Liu, C.; Metzkes-Ng, J.; Najmudin, Z.; Nishiuchi, M.; Paschke-Brühl, F.-L.; Pausch, R.; Püschel, T.; Rana, V.; Rehwald, M.; Sakaki, H.; Vescovi Pinochet, M. A.; Wang, P.; Zeil, K.; Ziegler, T.; Schramm, U.
Abstract
Ion acceleration through compact laser-plasma sources holds great potential for diverse applications, from medical treatments to fusion experiments. Achieving the required beam quality parameters demands a deep understanding and precise control of the laser-plasma interaction process. Our ongoing collaborative research at DRACO PW (HZDR) and J-KAREN-P (KPSI) laser systems focuses on exploring the promising regime of Relativistically Induced Transparency (RIT).
In previous studies [1], we observed high-performance proton beams (>60 MeV) in an expanded foil case, showcasing an optimum at the onset of target transparency. Subsequent experiments revealed even higher proton energies beyond 100 MeV [2], emphasizing the important role of the transparency onset time in optimizing beam parameters and enhancing process robustness. We employ a combination of particle and laser diagnostics to explore the correlation between transparency onset and acceleration performance.
This contribution highlights our recent investigations into spectral and spatial components of transmission and emission arising from the laser-plasma interaction. Building upon established methodologies [3,4], our approach involves spectral interferometry, using the unperturbed laser beam as a reference, and correlating findings with proton acceleration performance. Our results suggest a promising avenue for a focused analysis of spectral and spatial distribution, offering additional insights into the complexities of the laser-plasma interaction process. By emphasizing these aspects, we aim to deepen our understanding of factors influencing ion acceleration, contributing to the optimization of beam quality parameters.
[1] Dover, N.P. et al.: Light Sci. Appl. 12, 71 (2023).
[2] Ziegler, T. et al.: Nat. Phys. accepted (2024).
[3] Bagnoud, V. et al.: Phys. Rev. Lett. 118, 255003 (2017).
[4] Williamson, S.D.R. et al.: Phys. Rev. Appl. 14, 034018 (2020).
Keywords: laser plasma; laser proton acceleration; high power laser; laser ion acceleration; laser solid interaction
Involved research facilities
- Draco
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Lecture (Conference)
EPS Conference on Plasma Physics 2024, 08.-12.07.2024, Salamanca, España -
Lecture (Conference)
Advanced Accelerator Concepts Workshop 2024, 21.-26.07.2024, Naperville, United States of America
Permalink: https://www.hzdr.de/publications/Publ-39725
Investigating Recurrent Matere Bonds in Pertechnetate Compounds
Grödler, D.; Burguera, S.; Frontera, A.; Strub, E.
Abstract
In this manuscript we evaluate the X-ray structure of five new pertechnetate derivatives of general formula [M(H₂O)₄(TcO₄)₂], M=Mg, Co, Ni, Cu, Zn (compounds 1–5) and one perrhenate compound Zn(H₂O)₄(ReO₄)₂ (6). In these complexes the metal center exhibits an octahedral coordination with the pertechnetate units as axial ligands. All compounds exhibit the formation of directional Tc⋅⋅⋅O Matere bonds (MaBs) that propagate the [M(H₂O)₄(TcO₄)₂], into 1D supramolecular polymers in the solid state. Such 1D polymers are linked, generating 2D layers, by combining additional MaBs and hydrogen bonds (HBs). Such concurrent motifs have been analyzed theoretically, suggesting the noncovalent σ-hole nature of the MaBs. The interaction energies range from weak (~ −2 kcal/mol) for the MaBs to strong (~ −30 kcal/mol) for the MaB+HB assemblies, where HB dominates. In case of M=Zn, the corresponding perrhenate Zn(H₂O)₄(ReO₄)₂ complex, has been also synthesized for comparison purposes, resulting in the formation of an isostructural X-ray structure, corroborating the structure-directing role of Matere bonds.
Keywords: Pertechnetate; Perrhenate; matere bonds; supramolecular chemistry
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Chemistry - A European Journal 30(2024)22
DOI: 10.1002/chem.202400100
Cited 3 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39722
Trace-scale extraction of carrier-free tungsten radioisotope as a homolog of Sg using ionic liquid from acid solutions: Kinetic study
Attallah, M. F.; Elchine, D.; Grödler, D.; Margreiter, R.; Maslo, M.; Michel, M.; Petter Omtvedt, J.; Strub, E.; von Döllen, S.
Abstract
This study aimed to find a rapid extraction system for the preparation of a Seaborgium (Sg) aqueous chemistry experiment in the future. A new approach for extraction of ¹⁸¹W tracer as a lighter homolog of (Sg) by ionic liquids is explored. A natural tantalum target was activated by a beam of 9 MeV proton at Cologne University to produce carrier-free ¹⁸¹W. The preliminary batch extraction experiments of the carrier-free ¹⁸¹W from HCl and H₂SO₄ solutions have been evaluated. Different batch extraction parameters such as feed acidity, diluent type, ionic strength (KCl feed) and reducing agent as a function of time were explored. The obtained results demonstrated that the highest distribution of carrier-free ¹⁸¹W from 0.001 M acidic solutions using the used ionic liquid is observed. A significant rapid kinetic for the extraction of trace-scale using the used ionic liquid is achieved within 5 sec. The preliminary results are necessary to design the upcoming aqueous experiments of Sg. The next goal will be on-line experiments with the centrifuge system SISAK to develop the aqueous chemistry extraction of Sg using the most promising and adequate experimental setup.
Keywords: Chemistry of superheavy elements; Seaborgium; Separation of radioisotopes; Ionic liquid
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Separation and Purification Technology 331(2024)
DOI: 10.1016/j.seppur.2023.125418
Cited 2 times in Scopus
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Pertechnetates – A Structural Study Across the Periodic Table
Strub, E.; Grödler, D.; Zaratti, D.; Yong, C.; Dünnebier, L.; Bazhenova, S.; Roca Jungfer, M.; Breugst, M.; Zegke, M.
Abstract
The number of crystal structures of pertechnetates derived from aqueous solutions has been expanded from seven to over 30. We report the conversion of NH₄TcO₄ to aqueous HTcO₄ via acidic cation exchange. This is followed by the synthesis and structural elucidation of pertechnetate salts of alkaline earth (AE), transition metal I and lanthanoids (Ln) elements. Various degrees of hydration and coordination are discussed. Where possible, a comparison with the perrhenate homologues is made. The described syntheses and materials may be used as novel starting materials for extended technetium research.
Keywords: Technetium; Pertechnetates; Pertechnetic Acid; Crystallography
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Chemistry - A European Journal 30(2024)26
DOI: 10.1002/chem.202400131
Cited 1 times in Scopus
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Permalink: https://www.hzdr.de/publications/Publ-39719
Electronic Lieb Lattice Signatures Embedded in 2D Polymers with Square Pore
Zhang, Y.
Abstract
Exotic band features, such as Dirac cones and flat bands, arise directly from the lattice symmetry of materials. The Lieb lattice is one of the most intriguing topologies, because it possesses both Dirac cones and flat bands which intersect at the Fermi level. However, the synthesis of Lieb lattice materials remains a challenging task. Here, we explore two-dimensional polymers (2DPs) derived from zinc-phthalocyanine (ZnPc) building blocks with a square lattice (sql) as potential electronic Lieb lattice materials. By systematically varying the linker length (ZnPc-xP), we found that some ZnPc-xP exhibit a characteristic Lieb lattice band structure. Interestingly though, fes bands are also observed in ZnPc-xP. The coexistence of fes and Lieb in sql 2DPs challenges the conventional perception of the structure–electronic structure relationship. In addition, we show that manipulation of the Fermi level, achieved by electron removal or atom substitution, effectively preserves the unique characteristics of Lieb bands. The Lieb Dirac bands of ZnPc-4P shows a non-zero Chern number. Our discoveries provide a fresh perspective on 2DPs and redefine the search for Lieb lattice materials into a well-defined chemical synthesis task.
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Poster
Saxony Meets Lower Silesia: Science Across Borders, 17.06.2024, Dresden, Germany
Permalink: https://www.hzdr.de/publications/Publ-39716
Prospects for free-electron lasers powered by plasma-wakefield-accelerated beams
Galletti, M.; Assmann, R.; Couprie, M.-E.; Ferrario, M.; Giannessi, L.; Irman, A.; Pompili, R.; Wang, W.
Abstract
Plasma-wakefield-based acceleration technology has the potential to revolutionize the field of particle accelerators. By providing acceleration gradients orders of magnitude larger than conventional radiofrequency particle accelerators, this technology allows accelerators to be reduced to the centimetre length scale. It also provides a new compact approach for driving free-electron lasers, a valuable source of high-brilliance ultrashort coherent radiation within the infrared to X-ray spectral range for the study of subatomic matter, ultrafast dynamics of complex systems and X-ray nonlinear optics, among other applications. Several laboratories around the world are working on the realization of these new light sources, exploring different configurations for the plasma wakefield driver beam, plasma stage design and operational regime. This Review describes the operating principles of plasma accelerators, an overview of recent experimental milestones for plasma-driven free-electron lasers in self-amplified spontaneous emission and seeded configurations, and highlights the remaining major challenges in the field.
Keywords: plasma driven free electron laser
Involved research facilities
- Draco
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Nature Photonics 18(2024), 780-791
DOI: 10.1038/s41566-024-01474-3
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Data publication: Application of Phage Surface Display for the Identification of Eu3+-binding Peptides
Techert, G.; Drobot, B.; Braun, R.; Bloß, C.; Schönberger, N.; Matys, S.; Pollmann, K.; Lederer, F.
Abstract
1. Sequenzierdaten als Excel-File zu Europiumion-bindenden Peptiden
2. TRLFS-Rohdaten zu Bindungsstudien von potenziell Europiumion-bindenden Peptiden mit Europiumionen
3. TRLFS-Diagramme zu Bindungsstudien von potenziell Europiumion-bindenden Peptiden mit Europiumionen
Keywords: europium; REE recovery; phage surface display; peptides; next generation sequencing
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-02 Open access
DOI: 10.14278/rodare.3182
Versions: 10.14278/rodare.3183
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39712
Wettability-dependent dissolution dynamics of oxygen bubbles on Ti64 substrates
Dai, H.; Yang, X.; Schwarzenberger, K.; Heinrich, J.; Eckert, K.
Abstract
In this study, the dissolution of a single oxygen bubble on a solid surface, here Titanium alloy Ti64, in ultrapure water with different oxygen undersaturation levels is investigated. For that purpose, a combination of shadowgraph technique and planar laser-induced fluorescence is used to measure simultaneously the changes in bubble geometry and in the dissolved oxygen concentration around the bubble. Two different wettabilities of the Ti64 surface are adjusted by using plasma-enhanced chemical vapor deposition. The dissolution process on the solid surface involves two distinct phases, namely bouncing of the oxygen bubble at the Ti64 surface and the subsequent dissolution of the bubble, primarily by diffusion. By investigating the features of oxygen bubbles bouncing, it was found that the boundary layer of dissolved oxygen surrounding the bubble surface is redistributed by the vortices emerging during bouncing. This establishes the initial conditions for the subsequent second dissolution phase of the oxygen bubbles on the Ti64 surfaces. In this phase, the mass transfer of O2 proceeds non-homogeneously across the bubble surface, leading to an oxygen accumulation close to the Ti64 surface. We further show that the main factor influencing the differences in the dynamics of O2 bubble dissolution is the variation in the surface area of the bubbles available for mass transfer, which is determined by the substrate wettability. As a result, dissolution proceeds faster at the hydrophilic Ti64 surface due to the smaller contact angle, which provokes a larger surface area.
Keywords: Uncoated and coated Ti64 substrate; PLIF; Shadowgraph measurement; Concentration gradient; Bubble shape
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International Journal of Heat and Mass Transfer 236(2025), 126240
Online First (2024) DOI: 10.1016/j.ijheatmasstransfer.2024.126240
Permalink: https://www.hzdr.de/publications/Publ-39708
An SRF gun driving the ELBE IR-FEL with up to 1mA in CW
Abstract
At the electron accelerator for beams with high brilliance and low emittance (ELBE), the second version of a superconducting radio-frequency (SRF) photoinjector was brought into operation in 2014. After a period of commissioning, a gradual transfer to routine operation took place in 2017, so that now more than 1800h of user beam are generated every year. In addition to this routine operation with a few tens of microamperes, another important goal, the generation of an average current of 1 mA, which is high for electron linear accelerators, could now be demonstrated with our SRF gun. At the same time, this beam was already accelerated to almost 30 MeV by the ELBE LINAC and irradiated in one of the IR-FELs. This is particularly important with regard to the successor of the ELBE accelerator called DALI, which will be also fed by an SRF gun with a high average current. The contribution presents the most important steps for achieving the full beam current and summarizes related measurement results and findings. No fundamental difficulties were identified.
Keywords: SRF gun; photocathode; superconducting electron source; injector; ELBE; high current; mA; IR FEL
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- Superconducting Electron Linear Accelerator
- SRF Gun
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 39705) publication
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Invited lecture (Conferences)
10th Matter and Technologies annual meeting, 17.-20.09.2024, Berlin, Deutschland
PURL: https://indico.desy.de/event/45079/contributions/174026/ -
Invited lecture (Conferences)
69th ICFA Advanced Beam Dynamics Workshop on Energy Recovery Linacs (ERL2024), 24.-27.09.2024, Tsukuba, Japan -
Lecture (others)
Annual Gun Cluster Meeting 2024, 20.06.2024, Berlin, Deutschland
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Permalink: https://www.hzdr.de/publications/Publ-39705
Differential pressure measurements in bubble columns of different diameter, operated with various physical systems
Marchini, S.; Kipping, R.; Tim Dalu, K.
Abstract
The dataset was acquired over several measurement campaigns and contains differential pressure measurements in bubble columns of several diameters (100, 150, 330 mm) operated with gas in continuum (dry air) and liquid in batch. The fact that no humidification was provided was shown to have negligible influence. Liquid temperature was between 20-22°C. Pressure was atmospheric (column open to the environment).
For additional details, refer to the READ_ME and DETAILS_Setup files included in the dataset.
Keywords: bubble column; gas holdup; differential pressure; flow map
Related publications
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Gas Hold-up Estimation in Bubble Columns using Wall Pressure Fluctuations and …
ROBIS: 39567 has used this (Id 39704) publication of HZDR-primary research data
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-07-17 Restricted access
DOI: 10.14278/rodare.3057
Versions: 10.14278/rodare.3058
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Permalink: https://www.hzdr.de/publications/Publ-39704
Graphene bilayer as a template for manufacturing novel encapsulated 2D materials
Krasheninnikov, A.; Lin, Y.-C.; Suenaga, K.
Abstract
Bilayer graphene (BLG) has recently been used as a tool to stabilize the encapsulated single sheets of various layered materials and tune their properties. It was also discovered that the protecting action of graphene sheets makes it possible to synthesize completely new two-dimensional materials (2DMs) inside BLG by intercalating
various atoms and molecules. In comparison to the bulk graphite, BLG allows for easier intercalation and much larger increase in the inter-layer separation of the sheets. Moreover, it enables studying the atomic structure of the intercalated 2DM using high-resolution transmission electron microscopy. In this review, we summarize the recent
progress in this area, with a special focus on new materials created inside BLG. We compare the experimental findings with the theoretical predictions, pay special attention to the discrepancies and outline the challenges in the field. Finally, we discuss unique opportunities offered by the intercalation into 2DMs beyond graphene and their
heterostructures.
Keywords: 2D materials; intercalation; First-principles calculations
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39703) publication
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Nano Letters 24(2024)41, 12733-12740
DOI: 10.1021/acs.nanolett.4c03654
Permalink: https://www.hzdr.de/publications/Publ-39703
Data publication: Effects of mosaic crystal instrument functions on x-ray Thomson scattering diagnostics
Gawne, T. D.; Bellenbaum, H.; Fletcher, L. B.; Appel, K.; Bähtz, C.; Bouffetier, V.; Brambrink, E.; Brown, D.; Cangi, A.; Descamps, A.; Goede, S.; Hartley, N. J.; Herbert, M.-L.; Hesselbach, P.; Höppner, H.; Humphries, O. S.; Konôpková, Z.; Laso García, A.; Lindqvist, B.; Lütgert, J.; MacDonald, M. J.; Makita, M.; Martin, W.; Mishchenko, M.; Moldabekov, Z.; Nakatsutsumi, M.; Naedler, J.-P.; Neumayer, P.; Pelka, A.; Qu, C.; Randolph, L.; Rips, J.; Toncian, T.; Vorberger, J.; Wollenweber, L.; Zastrau, U.; Kraus, D.; Preston, T. R.; Dornheim, T.
Abstract
Datasets of various model source and instrument functions, simulations of dynamic structure factors, and experimental data from the publications, as well as figures.
Involved research facilities
- HIBEF
Related publications
- DOI: 10.1063/5.0222072 references this (Id 39702) publication
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-01 Open access
DOI: 10.14278/rodare.3179
Versions: 10.14278/rodare.3180
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39702
Investigation of the interactions of microorganisms with uranium in anthropogenic contaminated waters as basis for the development of a bioremediation technology. (Investigación de las interacciones de los microorganismos con el uranio en aguas contaminadas de origen antropogénico como base para el desarrollo de una tecnología de biorremediación)
Abstract
Uranium (U) mining has left a legacy of environmental contamination in the Federal States of Saxony and Thuringia (Germany). High concentrations of U and other heavy metals pose a potential threat to both the environment and human health, through contamination of soil and water. Additionally, it is well documented that other human activities, such as agronomic practices and military conflicts, have contributed to increasing the concentration of these contaminants. However, U has become one of the world's most important elements in the last 60 years due to its potential use in nuclear energy production. Therefore, it is essential to develop environmental rehabilitation programs in affected areas, along with adopting waste management practices that promote sustainability, including the possibility of recovering U from waste for reuse within the concept of circular economy.
Traditionally, physicochemical based conventional technologies have been used to remediate environments contaminated with U. However, these approaches tend to be costly, complex to apply, and ineffective for low concentrations of U. Hence, a promising alternative, less expensive, easy to implement, and effective for low U concentrations is bioremediation, based on the interaction mechanisms of biological systems with U. Based on extensive available literature, the main suggested strategies for U bioremediation include two approaches: biomineralization of U(VI) phosphates under oxic conditions and enzymatic reduction under anoxic conditions from soluble, highly mobile, and bioavailable U(VI) to insoluble, less mobile, and thus less bioavailable U(IV).
The aim of this PhD thesis was to characterize, through a multidisciplinary approach, two former German mine waters contaminated with U, Schlema-Alberoda and Pöhla (Wismut GmbH), in order to design a future U bioremediation strategy based on biostimulation of the native U-reducing microbial community.
The bioremediation of contaminated waters with low U concentrations shows a significant challenge, which can be addressed by stimulating U-reducing bacterial activity, as described in this PhD thesis. Moreover, this study not only provides new insights on the reduction of U(VI) to U(IV) but also emphasizes that the resulting product, U(V), is more stable than uraninite, thus increasing the potential of this strategy, considering the risk of U reoxidation.
Keywords: Uranium; Mine Water; Bioremediation
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 39701) publication
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Doctoral thesis
University of Granada, Granada, Spain, 2024
Mentor: Raff, J.; Merroun, M. L.; Krawczyk-Bärsch, E
372 Seiten
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Investigation of the interactions of microorganisms with uranium in anthropogenic contaminated waters as basis for the development of a bioremediation technology
Newman Portela, A.; Kvashnina, K.; Bazarkina, E.; Roßberg, A.; Bok, F.; Kassahun, A.; Raff, J.; Merroun, M. L.; Krawczyk-Bärsch, E.
Abstract
At the technical colloquium on September 5th, Antonio Newman will present the findings of his PhD thesis. This project was developed in collaboration between the University of Granada (Spain) and the Helmholtz-Zentrum Dresden-Rossendorf (Germany), in collaboration with Wismut GmbH.
The project first geochemically characterized the mine water from Schlema-Alberoda and Pöhla using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and High Pressure Ion Chromatography (HPIC). Simultaneously, it analysed the microbial community through sequencing of bacterial 16S rRNA and fungal ITS genes. Additionally, this work explored key metabolic pathways involved in the biogeochemical cycles of sulphur, nitrogen, and carbon using metatranscriptomic analysis to understand the differences in U concentrations between the two mine waters. The study also involved isolating, identifying, and biochemically characterizing fungi from these waters, searching for strains with U immobilization potential. Finally, a complementary bioremediation strategy was designed and optimized to reduce U in the Schlema-Alberoda mine water, using the native bacterial community and glycerol as an electron donor, while characterizing the reduced U products with spectroscopic (e.g., High-Energy-Resolution Fluorescence Detected X-Ray Absorption Near Edge Structure (HERFD-XANES) and (Extended X-Ray Absorption Fine Structure (EXAFS)) and microscopic techniques (e.g., HRTEM).
The most notable findings of this PhD thesis include the effectiveness of using glycerol as an electron donor to stimulate the native microbial community involved in reducing soluble U in the Schlema-Alberoda mine water as a bioremediation strategy. Additionally, the study reports not only the reduction of U(IV) but also surprisingly high proportions of biogenic stable U(V), which had not been previously documented in the literature.
Keywords: Uranium; Mine Water; Bioremediation
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 39698) publication
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Lecture (others)
Wismut GmbH - Technisches Kolloquium, 05.09.2024, Chemnitz, Germany
Permalink: https://www.hzdr.de/publications/Publ-39698
Heat flow data from the fungus Schizophyllum commune: example file for the software tool METABOLATOR
Fahmy, K.; Günther, A.; Bertheau, R.; Pape, D.
Abstract
The Excel file contains heat flow data from Schizophyllum commune cultures grown at 30 °C at different glucose concentrations. Measurements were carried out with a TAMIII instrument (TA-Waters) using 4 mL ampoules filled with 2 mL of growth medium.The heat flow curves show an oxidative phase followed by a fermentative phase at high glucose concentration. The two corresponding peaks can be evaluated indepndently by chosing the appropriate heat range. (The publication DOI:10.14278/rodare.3152 contains these data with the according analysis results). The Excel file serves also as a template for users to paste in their raw data. The format must not be changed for successful upload in METABOLATOR (DOI: 10.14278/rodare.3150). METABOLATOR is still being developed. Comments, reports on errors, suggestions can be sent to metabolator@hzdr.de
Keywords: metabolator; microcalorimetry; microbes; bacteria; growth; kinetics
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-09-30 Open access
DOI: 10.14278/rodare.3175
Versions: 10.14278/rodare.3176
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39694
Data publication: Gallium recovery from red mud: Integration of solvent extraction and siderophore assisted technologies
Dhiman, S.; Fuloria, N.; Ghosh, A.; Chaudhary, S.; Ziauddin Ahammad, S.; Tsushima, S.; Kelly, N.; Jain, R.
Abstract
The raw data that was used in the study.
Keywords: Leaching; GaLIophore; Cyphos IL 104; Desferrioxamine B; Density functional theory
Related publications
- DOI: 10.1016/j.jenvman.2024.122374 references this (Id 39691) publication
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-10-09 Open access
DOI: 10.14278/rodare.3187
Versions: 10.14278/rodare.3192 | 3188
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39691
Einstein–Stokes relation for small bubbles at the nanoscale
Zhou, Y.; Huang, M.; Tian, F.; Shi, X.; Zhang, X.
Abstract
As the physicochemical properties of ultrafine bubble systems are governed by their size, it is crucial to determine the size and distribution of such bubble systems. At present, the size or size distribution of nanometer-sized bubbles in suspension is often measured by either dynamic light scattering or the nanoparticle tracking analysis. Both techniques determine the bubble size via the Einstein–Stokes equation based on the theory of the Brownian motion. However, it is not yet clear to which extent the Einstein–Stokes equation is applicable for such ultrafine bubbles. In this work, using atomic molecular dynamics simulation, we evaluate the applicability of the Einstein–Stokes equation for gas nanobubbles with a diameter less than 10 nm, and for a comparative analysis, both vacuum nanobubbles and copper nanoparticles are also considered. The simulation results demonstrate that the diffusion coefficient for rigid nanoparticles in water is found to be highly consistent with the Einstein–Stokes equation, with slight deviation only found for nanoparticle with a radius less than 1 nm. For nanobubbles, including both methane and vacuum nanobubbles, however, large deviation from the Einstein–Stokes equation is found for the bubble radius larger than 3 nm. The deviation is attributed to the deformability of large nanobubbles that leads to a cushioning effect for collision-induced bubble diffusion.
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Journal of Chemical Physics 160(2024), 054109
DOI: 10.1063/5.0189490
Permalink: https://www.hzdr.de/publications/Publ-39688
SU(2) gauge theory with one and two adjoint fermions towards the continuum limit
Athenodorou, A.; Bennett, E.; Bergner, G.; Butti, P.; Lenz, J.; Lucini, B.
Abstract
We provide an extended lattice study of the SU(2) gauge theory coupled to one Dirac fermion flavour (Nf=1Nf=1) transforming in the adjoint representation as the continuum limit is approached. This investigation is supplemented by numerical results obtained for the SU(2) gauge theory with two Dirac fermion flavours (Nf=2Nf=2) transforming in the adjoint representation, for which we perform numerical investigations at a single lattice spacing value, which is analysed together with earlier calculations. The purpose of our study is to advance the characterisation of the infrared properties of both theories, which previous investigations have concluded to be in the conformal window. For both, we determine the mass spectrum and the anomalous dimension of the fermion condensate using finite-size hyperscaling of the spectrum, mode number analysis of the Dirac operator (for which we improve on our previous proposal) and the ratio of masses of the lightest spin-2 particle over the lightest scalar. All methods provide a consistent picture, with the anomalous dimension of the condensate γ∗γ∗ decreasing significantly as one approaches the continuum limit for the Nf=1Nf=1 theory towards a value consistent with γ∗=0.174(6)γ∗=0.174(6), while for Nf=2Nf=2 the anomalous dimension decreases more slowly with ββ. A chiral perturbation theory analysis show that the infrared behaviour of both theories is incompatible with the breaking of chiral symmetry.
Keywords: High Energy Physics
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Contribution to WWW
https://arxiv.org/abs/2408.00171
DOI: 10.48550/arXiv.2408.00171
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Permalink: https://www.hzdr.de/publications/Publ-39686
DRACO-HELIPORT integration for metadata enhanced data-acquisition
Lokamani, M.; Pape, D.; Knodel, O.; Bock, S.; Schramm, U.; Kelling, J.; Juckeland, G.
Abstract
The Dresden laser acceleration source (DRACO) is a state-of-the-art high-power ultra-short pulse laser system[1,2],
that uses an Amplitude Technologies Pulsar architecture to form main and diagnostics beams at different focal lengths and target density conditions.
The setup can deliver from 6J to 45J of pulse energy at a typical pulse duration of 30fs and a typical frequency of 1Hz.
During the diagnostic phase, the beam characteristics are recorded in the form of images and several instrument parameters,
that shape the beam to desired characteristics.
In this talk, we present our approach of implementing FAIR principles to DRACO
operations and monitoring using our in-house guidance system HELIPORT[3],
with the goal of making them reusable irrespective of the downstream experiment.
We employ FAIR workflows[4] to post-process data collected by DRACO's built-in data
acquisition system and enrich it with metadata for subsequent utilization in
machine-learning and optimization algorithms for accurate control of the beam characteristics.
The intergration of DRACO and HELIPORT demonstrates the first step towards establishing
a digital twin for the laser source facility at HZDR.
[1] First results with the novel Petawatt laser acceleration facility in Dresden, U. Schramm et al, J. Phys. Conf. Ser. 874 012028 (2017)
[2] High dynamic, high resolution and wide range single shot temporal pulse contrast measurement, T. Oksenhendler et. al., Opt. Express 25, 12588-12600 (2017)
[3] HELIPORT: A Portable Platform for FAIR {Workflow | Metadata | Scientific Project Lifecycle} Management and Everything, O. Knodel et. al., P-RECS (2021)
[4] FAIR Computational workflows, C. Goble et. al., Data Intelligence (2020) 2, 108 (2020)
Keywords: Research Software Engineering; DRACO; HELIPPOT; Data mangement
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- Draco
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 39685) publication
-
Lecture (Conference)
Nobugs 2024, 23.-27.09.2024, Grenoble, France
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Permalink: https://www.hzdr.de/publications/Publ-39685
Nitrosyl and Thionitrosyl Complexes of Technetium and Rhenium and Their Reactions with Hydrotris(pyrazolyl)borates
Sawallisch, T. E.; Abdulkader, A.; Nowak, D.; Hagenbach, A.; Abram, U.
Abstract
The very limited number of structurally known thionitrosyl complexes of technetium was increased by the synthesis of [Tcᴵᴵ(NS)Cl₃(PPh₃)₂] (3) and [Tcᴵᴵ(NS)Cl₃(PPh₃)(OPPh₃)] (4) and their reaction products with hydrotris(pyrazolyl)borates, {HB(pzᴿ)₃}⁻. Similar reactions were conducted with [Tcᴵ(NO)Cl₂(PPh₃)₂(CH₃CN)] and related rhenium thionitrosyls. Remarkably, most such reactions result in a rapid cleavage of the boron–nitrogen bonds of the ligands and the formation of pyrazole complexes of the two group 7 metals. Only one compound with an intact {HB(pzᴿ)₃}⁻ ligand could be isolated: the technetium(I) complex [Tcᴵ(NO)Cl(PPh₃){HB(pz)₃}] (2). Other products show the coordination of one or four neutral pyrazole ligand(s) in the coordination spheres of technetium generated by thermal decomposition of the pyrazolylborates [Tcᴵ(NO)Cl₂(PPh₃)₂(pzᴴ)] (1) and [Tcᴵ(NS)Cl(pzᴴᴹᵉ²)₄]⁺ (5). Reactions with the corresponding thionitrosylrhenium complex [Reᴵᴵ(NS)Cl₃(PPh₃)₂] require higher temperatures and only compounds with one pyrazole ligand, [Reᴵ(NS)Cl₂(PPh₃)(pzᴴᴿ)] (6a–6c), were isolated. The products were studied spectroscopically and by X-ray diffraction.
Keywords: technetium; rhenium; nitrosyl complexes; thionitrosyl complexes; pyrazolylborates
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Molecules 29(2024)16, 3865
DOI: 10.3390/molecules29163865
Permalink: https://www.hzdr.de/publications/Publ-39684
UniCAR T-Cell Potency—A Matter of Affinity between Adaptor Molecules and Adaptor CAR T-Cells?
Boutier, H.; Rodrigues Loureiro, L. R.; Hoffmann, L.; Arndt, C.; Feldmann, A.; Bartsch, T.; Bachmann, M.
Abstract
Manuscript published in IJMS + figures
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-09-30 Open access
DOI: 10.14278/rodare.3167
Versions: 10.14278/rodare.3168
License: CC-BY-4.0
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Permalink: https://www.hzdr.de/publications/Publ-39682
Substrate deformability and applied normal force are coupled to change nanoscale friction
Abstract
Amonton's law of friction states that the friction force is proportional to the normal force in magnitude, and the slope gives a constant friction coefficient. In this work, with molecular dynamics simulation, we study how the kinetic friction at the nanoscale deviates qualitatively from the relation. Our simulation demonstrates that the friction behavior between a nanoscale AFM tip and an elastic graphene surface is regulated by the coupling of the applied normal force and the substrate deformability. First, it is found that the normal load-induced substrate deformation could lower friction at low load while increasing it at high load. In addition, when the applied force exceeds a certain threshold another abrupt change in friction behavior is observed, i.e., the stick–slip friction changes to the paired stick–slip friction. The unexpected change in friction behavior is then ascribed to the change of the microscopic contact states between the two surfaces: the increase in normal force and the substrate deformability together lead to a change in the energy landscape experienced by the tip. Finally, the Prandtl–Tomlinson model also validates that the change in friction behavior can be interpreted in terms of the energy landscape.
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Nanoscale Advances 6(2024), 4922-4937
DOI: 10.1039/D4NA00252K
Permalink: https://www.hzdr.de/publications/Publ-39680
Transition from ferromagnetic to noncollinear to paramagnetic state with increasing Ru concentration in FeRu films
Lisik, J.; Rojas, M.; Myrtle, S.; Ryan, D. H.; Hübner, R.; Omelchenko, P.; Abert, C.; Ducevic, A.; Suess, D.; Soldatov, I.; Schaefer, R.; Seyd, J.; Albrecht, M.; Girt, E.
Abstract
The structural and magnetic properties of sputter-deposited Fe100−xRux films were studied for x < 50. The crystal structure of Fe100−xRux is shown to be predominantly body-centered cubic for x < 13 and to undergo a gradual transition to hexagonal close-packed in the Ru concentration range 13 < x < 20. Magnetic measurements indicate that the addition of Ru to Fe gives rise to a noncollinear magnetic alignment between Fe atoms in the body-centered cubic FeRu alloys, while the hexagonal close-packed FeRu alloys exhibit paramagnetic behavior. A simple atomistic model was used to show that the competition between ferromagnetic coupling of neighboring Fe atoms and antiferromagnetic coupling of Fe atoms across Ru atoms in cubic FeRu structures can induce noncollinear magnetic order. Magnetic multilayer structures used in thin-film magnetic devices make extensive use of both Fe and Ru layers. Our results reveal that the presence of even a small amount of Ru in Fe influences the magnetic order of Fe, which could impact the performance of these devices.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39679) publication
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Physical Review B 110(2024), 104429
DOI: 10.1103/PhysRevB.110.104429
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Permalink: https://www.hzdr.de/publications/Publ-39679
Magnetic nanomembranes: from soft robotics to eco-sustainable magnetoelectronics
Abstract
Composites consisting of magnetic fillers in polymers and elastomers enable new types of applications in soft robotics, reconfigurable actuation and sensorics. In particular, soft-bodied robots emerge as the closest synthetic system analogous to living organisms mimicking their mechanical behavior and going beyond in performance. We will introduce lightweight, durable, untethered and ultrafast soft-bodied robots that can walk, swim, levitate, transport cargo, and perform collaborative tasks being driven using magnetic far fields [1,2] and near fields [3,4]. Reconfigurable magnetic origami actuators [2] can be equipped with ultrathin magnetosensitive e-skins [5], which help to assess the magnetic state of the actuator (magnetized vs. non-magnetized), decide on its actuation pattern and control sequentiality and quality of the folding process. The on-board sensing adds awareness to soft-bodied magnetic actuators enabling them to act and be controlled similar to conventional robotic devices [6].
Magnetic composites can be readily used to realise not only actuators but also magnetic field sensors [7]. We demonstrate that printed magnetoelectronics can be stretchable, skin-conformal, capable of detection in low magnetic fields and withstand extreme mechanical deformations [8,9]. We feature the potential of our skin-conformal sensors in augmented reality settings [10,11], where a sensor-functionalized finger conducts remote and touchless control of virtual objects manageable for scrolling electronic documents and zooming maps under tiny permanent magnet [8].
Furthermore, we put forth technology to realise magnetic field sensors, which can be printed and self-heal upon mechanical damage [12]. This opens exciting perspectives for magnetoelectronics in smart wearables, interactive printed electronics and motivates further explorations towards the realisation of recyclable magnetoelectronics [13]. For the latter, we will discuss eco-sustainable, namely biocompatible and biodegradable magneto sensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants and health monitoring [6].
[1] X. Wang et al., Untethered and ultrafast soft-bodied robots. Commun. Mater. 1, 67 (2020).
[2] M. Ha et al., Reconfigurable magnetic origami actuators with on-board sensing for guided assembly. Adv. Mater. 33, 2008751 (2021).
[3] M. Richter et al., Locally addressable energy efficient actuation of magnetic soft actuator array systems. Advanced Science 2302077 (2023).
[4] L. Masjosthusmann et al., Miniaturized variable stiffness gripper locally actuated by magnetic fields. Advanced Intelligent Systems 6, 2400037 (2024).
[5] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Adv. Funct. Mater. (Review) 31, 2007788 (2021).
[6] E. S. Oliveros Mata et al., Magnetically aware actuating composites: Sensing features as inspiration for the next step in advanced magnetic soft robotics. Phys. Rev. Appl. (Review) 20, 060501 (2023).
[7] L. Guo et al., Printable magnetoresistive sensors: A crucial step toward unconventional magnetoelectronics. Chinese Journal of Structural Chemistry (Review) 100428 (2024).
[8] M. Ha et al., Printable and stretchable giant magnetoresistive sensors for highly compliant and skin-conformal electronics. Adv. Mater. 33, 2005521 (2021).
[9] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[10] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[11] P. Makushko et al., Flexible magnetoreceptor with tunable intrinsic logic for on-skin touchless human-machine interfaces. Adv. Funct. Mater. 31, 2101089 (2021).
[12] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).
[13] X. Wang et al., Printed magnetoresistive sensors for recyclable magnetoelectronics. J. Mater. Chem. A 12, 24906 (2024).
Keywords: flexible magnetic field sensors; shapeable magnetoelectronics; printed magnetoelectronics; soft magnetic composites; magnetic soft robots
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39678) publication
-
Invited lecture (Conferences)
The 5th China New Materials Industry Development Conference, 16.-18.10.2024, Wuhan, China
Permalink: https://www.hzdr.de/publications/Publ-39678
Flow optimized membraneless alkaline water electrolysis
Rox, H.; Schoppmann, K.; Gatter, J.; Frense, E.; Yang, X.; Rüdiger, F.; Fröhlich, J.; Eckert, K.
Abstract
Highly simplified electrolyzer designs in the form of a membraneless alkaline electrolyzer (MAEL) allow higher current densities compared to conventional designs and result as well in lower capital expenditures. In addition, MAELs provide very good access to the electrodes, making them ideal for research to better understand bubble formation and detachment. Since there is no membrane or diaphragm to separate the products, H2 and O2, the cell design to direct the electrolyte flow is critical.
Using CFD and current simulations, an optimized cell geometry was developed to ensure constant conditions for the water splitting reaction over the entire electrode. Particle Image Velocimetry and Shadowgraphy were used to systematically study the influence of the electrolyte flow as driving force for an effective H2 and O2 separation. It is shown that below a critical Recrit the evolving bubbles are stuck on the porous electrodes and lead to a blockage of electrochemical active sites as well as to an increase of the cell potential. On the other hand, high gas purity and overall efficiency were observed at the optimal flow rate to current density ratio. Thus, the present study proves the concept of the newly developed membraneless electrolyzer.
Keywords: Alkaline electrolysis; Membraneless electrolyzer; Flow-through electrode; Shadowgraphy; Particle image velocimetry
Involved research facilities
- Data Center
-
Lecture (Conference)
16th International Conference on Gas–Liquid and Gas–Liquid–Solid Reactor Engineering, 02.-05.09.2024, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-39676
Mineral chemistry of the Geyer SW tin skarn deposit: understanding variable fluid/rock ratios and metal fluxes
Gutzmer, J.; Meyer, N.; Burisch, M.; Krause, J.; Scheibert, H.; Markl, G.
Abstract
The Geyer tin skarn in the Erzgebirge, Germany, comprises an early skarnoid stage (stage I, ~ 320 Ma) and a younger
metasomatic stage (stage II, ~ 305 Ma), but yet, the source and distribution of Sn and the physicochemical conditions
of skarn alteration were not constrained. Our results illustrate that contact metamorphic skarnoids of stage I contain
only little Sn. REE patterns and elevated concentrations of HFSE indicate that garnet, titanite and vesuvianite of stage I
formed under rock-buffered conditions (low fluid/rock ratios). Prograde assemblages of stage II, in contrast, contain two
generations of stanniferous garnet, titanite-malayaite and vesuvianite. Oscillation between rock-buffered and fluid-buffered
conditions are marked by variable concentrations of HFSE, W, In, and Sn in metasomatic garnet. Trace and REE element
signatures of minerals formed under high fluid/rock ratios appear to mimic the signature of the magmatic-hydrothermal
fluid which gave rise to metasomatic skarn alteration. Concomitantly with lower fluid-rock ratio, tin was remobilized
from Sn-rich silicates and re-precipitated as malayaite. Ingress of meteoric water and decreasing temperatures towards
the end of stage II led to the formation of cassiterite, low-Sn amphibole, chlorite, and sulfide minerals. Minor and trace
element compositions of cassiterite do not show much variation, even if host rock and gangue minerals vary significantly,
suggesting a predominance of a magmatic-hydrothermal fluid and high fluid/rock ratios. The mineral chemistry of major
skarn-forming minerals, hence, records the change in the fluid/rock ratio, and the arrival, distribution, and remobilization
of tin by magmatic fluids in polyphase tin skarn systems.
Keywords: Erzgebirge; Tin skarn; Garnet; Cassiterite; Mineral chemistry
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Mineralium Deposita (2024)
DOI: 10.1007/s00126-024-01297-w
Permalink: https://www.hzdr.de/publications/Publ-39675
Data publication: Strong transient magnetic fields induced by THz-driven plasmons in graphene disks
Han, J. W.; Sai, P.; But, D.; Uykur, E.; Winnerl, S.; Kumar, G.; Chin, M. L.; Myers-Ward, R. L.; Dejarld, M. T.; Daniels, K. M.; Murphy, T. E.; Knap, W.; Mittendorff, M.
Abstract
In the zip file all metadata and raw data of experiements and simulations are collected and sorted into different folders
Keywords: Transient magnetic fields; Faraday rotation; Graphene; Plasmonics
Involved research facilities
- F-ELBE
Related publications
- DOI: 10.1038/s41467-023-43412-x references this (Id 39665) publication
-
Strong transient magnetic fields induced by THz-driven plasmons in graphene …
ROBIS: 37544 has used this (Id 39665) publication of HZDR-primary research data
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-09-26 Restricted access
DOI: 10.14278/rodare.3160
Versions: 10.14278/rodare.3161
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Permalink: https://www.hzdr.de/publications/Publ-39665
Electronic-Structure Interpretation: How Much Do We Understand Ce L3 XANES?
Abstract
Historically, cerium has been attractive for pharmaceutical and
industrial applications. The cerium atom has the unique ability
to cycle between two chemical states (Ce(III) and Ce(IV)) and
drastically adjust its electronic configuration: [Xe] 4f15d16s2 in
response to a chemical reaction. Understanding how electrons
drive chemical reactions is an important topic. The most direct
way of probing the chemical and electronic structure of
materials is by X-ray absorption spectroscopy (XAS) or X-ray
absorption near-edge structure (XANES) in high energy reso-
lution fluorescence detection (HERFD) mode. Such measure-
ments at the Ce L3 edge have the advantage of a high
penetration depth, enabling in-situ reaction studies in a time-
resolved manner and investigation of material production or
material performance under specific conditions. But how much
do we understand Ce L3 XANES? This article provides an
overview of the information that can be extracted from
experimental Ce L3 XAS/XANES/HERFD data. A collection of
XANES data recorded on various cerium systems in HERFD
mode is presented here together with detailed discussions on
data analysis and the current status of spectral interpretation,
including electronic structure calculations.
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 39658) publication
-
Chemistry - A European Journal 30(2024)46, e202400755
DOI: 10.1002/chem.202400755
Cited 1 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39658
Hydrothermal synthesis of (Zr,U)SiO4 : an efficient pathway to incorporate uranium into zircon
Estevenon, P.; Barral, T.; Avallone, A.; Jeffredo, M.; de la Hos, A.; Strzelecki, A.; Le Goff, X.; Szenknect, S.; Kvashnina, K.; Moisy, P.; Podor, R.; Guo, X.; Dacheux, N.
Abstract
he preparation of synthetic (Zr,U)SiO4 solid solution is challenging, as the conventional high-temperature
solid-state method limits the solubility of uranium (4 ± 1 mol%) in the orthosilicate phase due to its
thermodynamic instability. However, these compounds are of great interest as a result of (Zr,U)SiO4 solid
solutions, with uranium contents exceeding this concentration, being observed as corium phases formed
during nuclear accidents. It has been identified that hydrothermal synthesis pathways can be used for the
formation of the metastable phase, such as USiO4 . The investigation carried out in this study has indeed
led to the confirmation of metastable (Zr,U)SiO4 compounds with high uranium contents being formed. It
was found that (Zr,U)SiO4 forms a close-to-ideal solid solution with uranium loading of up to 60 mol% by
means of hydrothermal treatment for 7 days at 250 °C, at pH = 3 and starting from an equimolar reactant
concentration equal to 0.2 mol L−1 . A purification procedure was developed to obtain pure silicate com-
pounds. After purification, these compounds were found to be stable up to 1000 °C under an inert atmo-
sphere (argon). The characterisation methods used to explore the synthesis and thermal stability included
powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and Raman spectroscopies, scanning
electron microscopy (SEM) and thermogravimetric analysis (TGA).
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 39657) publication
-
Dalton Transactions 53(2024), 13782-13794
DOI: 10.1039/d4dt01604a
Permalink: https://www.hzdr.de/publications/Publ-39657
Efficient removal of succinic acid by continuous hydrodynamic cavitation combined with ozone and side influent injection
Huaccallo Aguilar, Y.; Kumar, A.; Meier, M.; Paul Lerch, A.; Reinecke, S.
Abstract
Micropollutants (MPs) encompass a range of human-made pollutants present in trace amounts in environmental systems. MPs include pharmaceuticals, personal care products, pesticides, persistent organic pollutants, micro- and nano-plastics, and artificial sweeteners, all posing ecological risks. Conventional municipal wastewater treatment methods often face challenges in completely removing MPs due to their chemical characteristics, stability, and resistance to biodegradation. In this research, a novel Advanced Oxidation Process, combining hydrodynamic cavitation (HC) with dissolved ozone (O3), was employed to effectively degrade succinic acid (SA), a representative ozone-resistant compound. The HC/O3 process was run to treat different synthetic effluents, focusing on evaluating the influence of O3-to-total organic carbon (TOC) ratio, cavitation number (Cv) and O3 dosage. Notably, the results from a series of 14 experiments highlighted the critical significance of a low O3-to-TOC ratio value of 0.08 mg/mg and Cv value of 0.056 in HC for achieving efficient SA removal of 41.2% from an initial SA solution (106.3 mg/L). Regarding a series of four proof-of-concept experiments and their replications, the average TOC removal reached 62% when treating wastewater treatment plant effluent spiked with SA. This significant removal rate was achieved under initial conditions: Cv of 0.02, O3-to-TOC ratio set at 0.77 mg/mg, TOC concentration of 47.7 mg/L, 106 mg/L of SA, and a temperature of 25ºC. Notably, the electrical energy per order required for the 62% reduction in TOC was a modest 12.5 kWh/m3/order, indicating the potential of the continuous HC/O3 process as a promising approach for degrading a wide range of MPs.
Keywords: Cavitation number; ozone-resistant substances; energy consumption; wastewater; AOP; mineralization
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Journal of Environmental Management 370(2024), 122795
DOI: 10.1016/j.jenvman.2024.122795
Permalink: https://www.hzdr.de/publications/Publ-39656
Electrical Conductivity of Warm Dense Hydrogen from Ohm's Law and Time-Dependent Density Functional Theory
Ramakrishna, K.; Lokamani, M.; Cangi, A.
Abstract
Understanding the electrical conductivity of warm dense hydrogen is critical for both fundamental physics and applications in planetary science and inertial confinement fusion. We demonstrate how to calculate the electrical conductivity using the continuum form of Ohm's law, with the current density obtained from real-time time-dependent density functional theory. This approach simulates the dynamic response of hydrogen under warm dense matter conditions, with temperatures around 30,000 K and mass densities ranging from 0.02 to 0.98 g/cc. We systematically address finite-size errors in real-time time-dependent density functional theory, demonstrating that our calculations are both numerically feasible and reliable. Our results show good agreement with other approaches, highlighting the effectiveness of this method for modeling electronic transport properties from ambient to extreme conditions.
Keywords: Electronic structure; Density functional theory; Time-dependent density functional theory; Electrical conductivity; Warm dense matter; Hydrogen
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Contribution to WWW
https://doi.org/10.48550/arXiv.2409.15160
DOI: 10.48550/arXiv.2409.15160
Permalink: https://www.hzdr.de/publications/Publ-39653
Advances in drop and bubble profile analysis tensiometry
Javadi, A.; Liggieri, L.; Aksenenko, E. V.; Gochev, G. G.; Miller, R.
Abstract
Profile analysis tensiometry (PAT) with drops and bubbles is a successful methodology to characterize liquid–fluid interfaces. Questions about the most suitable size of drops and bubbles have been solved now on the basis of dimensionless numbers. The consideration of the standard deviation between measured and calculated liquid profiles as a sensitive measure for the applicability of PAT provides a tool for its correct use. For solutions of highly surface-active compounds, bulk depletion effects can cause systematic errors in the analysis of adsorption kinetics, equations of state, and the visco-elastic interfacial behavior of liquid adsorption layers. Great progress has been made in measurements of interfacial dilational rheology with large amplitude perturbations providing additional information about structure and dynamics of complex adsorption layers. Also, first attempts are successfully made to use artificial intelligence (AI) to enhance the efficiency of PAT applications. Thus, PAT has established a solid position in surface science.
Keywords: Dilational interfacial visco-elasticity; Drop profile analysis tensiometry; Gauss-Laplace equation
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Current Opinion in Colloid & Interface Science 73(2024), 101846
DOI: 10.1016/j.cocis.2024.101846
Permalink: https://www.hzdr.de/publications/Publ-39651
Antiferromagnetic nanoscale bit arrays of magnetoelectric Cr2O3 thin films
Rickhaus, P.; Pylypovskyi, O.; Seniutinas, G.; Borras, V.; Lehmann, P.; Wagner, K.; Zaper, L.; Prusik, P.; Makushko, P.; Veremchuk, I.; Kosub, T.; Hübner, R.; Sheka, D. D.; Maletinsky, P.; Makarov, D.
Abstract
Magnetism of oxide antiferromagnets (AFMs) has been studied in single crystals and extended thin films. The properties of AFM nanostructures still remain underexplored. Here, we report on the fabrication and magnetic imaging of granular 100-nm-thick magnetoelectric \ch{Cr2O3} films patterned in circular bits with diameters ranging from 500 down to 100\,nm. With the change of the lateral size, the domain structure evolves from a multidomain state for larger bits to a single domain state for the smallest bits. Based on spin-lattice simulations, we show that the physics of the domain pattern formation in granular AFM bits is primarily determined by the energy dissipation upon cooling, which results in motion and expelling of AFM domain walls of the bit. Our results provide a way towards the fabrication of single domain AFM-bit-patterned memory devices and the exploration of the interplay between AFM nanostructures and their geometric shape.
Keywords: Cr2O3; bit memory
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Nano Letters 24(2024)42, 13172-13178
DOI: 10.1021/acs.nanolett.4c03044
Permalink: https://www.hzdr.de/publications/Publ-39649
GMP-compatible production of adapter CAR T cells using a CliniMACS Prodigy®
Jutrzenka-Trzebiatowski, A.; Daglar, C.; Arndt, C.; Rodrigues Loureiro, L. R.; Bachmann, M.; Feldmann, A.
Abstract
Over the last decade chimeric antigen receptor (CAR) T cell immunotherapy demonstrated great success in hematological malignancies. On the downside, however, these therapies are also accompanied by various adverse events, such as cytokine release syndrome or on-target off-tumor effects. To overcome these hurdles, we have developed switchable adapter CAR systems, namely the UniCAR and RevCAR technology. T cells modified to express such adapter CARs can be not only directed against a certain tumor specific target but also reversibly switched ON and OFF allowing a steerable therapy. So far, adapter CAR T cells potently eradicated tumor cells of various entities both in vitro and in vivo. For an application in patients, adapter CAR T cells need to be produced according to GMP requirements. In that regard, the CliniMACS Prodigy® represents a powerful closed-system manufacturing instrument enabling an automated production process with reduced risk for contamination and hands-on time. Here, we present successful generation of adapter CAR T cells using a CliniMACS Prodigy® which yielded in high transduction rates and cell numbers. Moreover, CliniMACS Prodigy® produced adapter CAR T cells potently killed tumor cells in a steerable manner demonstrating their high potential for a clinical application.
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Poster
2024 Annual Meeting - Study Group Tumor Immunology, 08.10.2024, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-39647
Turning immunosuppression into T cell activation: Using RevCAR system to target immune checkpoints
Crespo, E.; Rodrigues Loureiro, L. R.; Stammberger, A.; Rupp, L.; Hoffmann, L.; Ball, C.; Bachmann, M.; Schmitz, M.; Feldmann, A.
Abstract
Chimeric Antigen Receptor (CAR) T cells are effective at targeting tumor cells, particularly in hematological malignancies. A safer, switchable modular system called RevCAR has been developed to address dangerous side-effects. This system includes RevCAR T cells, which cannot bind to targets on their own, and a bispecific target module (RevTM). The functionality of this system depends on the presence of RevTM, which acts as a safety switch. Additionally, different RevTMs can be used with the same T cells to target various antigens, providing greater flexibility. To effectively treat solid tumors, however, it is necessary to overcome the immunosuppressive tumor microenvironment. To address this, new RevTMs were created to target immune checkpoint PD-L1, which cancer cells often upregulate to evade the immune system. Our research demonstrated that these new RevTMs enable RevCAR T cells to specifically target and kill a wide range of PD-L1-expressing cells in both monolayer and 3D models. The RevCAR T cells also released pro-inflammatory cytokines and expressed activation markers after co-culture. Furthermore, we validated an AND-gated targeting approach that simultaneously targets a tumor-associated antigen (TAA) and an immune checkpoint. These findings suggest a promising new strategy for applying the RevCAR platform to the treatment of solid tumors.
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Lecture (Conference)
2024 Annual Meeting - Study Group Tumor Immunology, 07.10.2024, Dresden, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-39646
An experimental quantification analysis of aerosol inhalation of real people in dynamic scenarios
Cavagnola, M. A.; Aldnifat, A.; Kryk, H.; Hampel, U.; Lecrivain, G.
Abstract
The establishment of inhaled aerosols plays a significant role in risk assessment regarding air pollution and spreading of diseases. It is also of importance for evaluating lung deposition of particles and hence, the effectiveness of inhaled drug delivery systems. When it comes to air pollution or airborne diseases, there is a broad discussion whether ventilation by frequent window opening is sufficient for providing a sufficient amount of fresh air or if technical air purification devices based on e.g. HEPA filters are page better solutions for public spaces. Furthermore, there is another discussion ongoing, whether a well-guided laminar flow or a high degree of mixing within a room is more beneficial. The latter, on the one hand distributes the potentially virus-laden aerosols in the whole room, but on the other hand reduces the peak concentrations of these aerosols clouds by magnitudes.
The objective of this study is to answer to these queries by performing aerosol propagation experiments in order to estimate the potential aerosol inhalation of people in dynamic situations. To achieve this, an aerosol generator is used for aerosolizing a solution of water/MgCl2, which is collected in removible filters located in breathing masks used by the people during the experiment. The quantification of the inhaled aerosol is carried out by extracting the Mg from the mask and measuring it using inductively coupled plasma mass spectromestry technique (ICP-MS). Experiments will be performed in a demonstrator room under different flow conditions. The data from different scenarios will be processed in order to obtain a transference function that can relate the aerosol source with the aerosol receivers.
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Lecture (Conference)
1st European Fluid Dynamics Conference, 16.09.2024, Aachen, Deutschland
Permalink: https://www.hzdr.de/publications/Publ-39644
Transcriptomic and epigenetic landscape of nimorazole-enhanced radiochemotherapy in head and neck cancer
Besso, M. J.; Bitto, V.; Koi, L.; Hadiwikarta, W. W.; Conde-Lopez, C.; Euler-Lange, R.; Bonrouhi, M.; Schneider, K.; Linge, A.; Krause, M.; Baumann, M.; Kurth, I.
Abstract
Background: Hypoxia remains a challenge for the therapeutic management of head and neck squamous cell carcinoma (HNSCC). The combination of radiotherapy with nimorazole has shown treatment benefit in HNSCC, but the precise underlying molecular mechanisms remain unclear. Purpose: To assess and to characterize the transcriptomic/epigenetic landscape of HNSCC tumor models showing differential therapeutic response to fractionated radiochemotherapy (RCTx) combined with nimorazole. Materials/methods: Bulk RNA-sequencing and DNA methylation experiments were conducted using untreated and treated HNSCC xenografts after 10 fractions of RCTx with and without nimorazole. These tumor models (FaDu, SAS, Cal33, SAT and UT-SCC-45) previously showed a heterogeneous response to RCTx with nimorazole. The prognostic impact of candidate genes was assessed using clinical and gene expression data from HNSCC patients treated with primary RCTx within the DKTK-ROG. Results: Nimorazole responder and non-responder tumor models showed no differences in hypoxia gene signatures However, non-responder models showed upregulation of metabolic pathways. From that, a subset of 15 differentially expressed genes stratified HNSCC patients into low and high-risk groups with distinct outcome. Conclusion: In the present study, we found that nimorazole non-responder models were characterized by upregulation of genes involved in Retinol metabolism and xenobiotic metabolic process pathways, which might contribute to identify mechanisms of resistance to nitroimidazole compounds and potentially expand the repertoire of therapeutic options to treat HNSCC.
Keywords: Hypoxia; Head and neck squamous cell carcinoma; Radiochemotherapy; Nimorazole; Biomarkers
Involved research facilities
- OncoRay
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Radiotherapy and Oncology 199(2024), 110348
DOI: 10.1016/j.radonc.2024.110348
Cited 1 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39642
Data publication: Cavity-mediated thermal control of metal-to-insulator transition in 1T-TaS2
Jarc, G.; Mathengattil, S. Y.; Montanaro, A.; Giusti, F.; Rigoni, E. M.; Sergo, R.; Fassioli, F.; Winnerl, S.; Zilio, S. D.; Mihailovic, D.; Prelovšek, P.; Eckstein, M.; Fausti, D.
Abstract
Original datasets corresponding to the publication.
Keywords: metal-to-insulator transition; strong light-matter coupling; terahertz Fabry-Pérot cavity; phase transition
Related publications
- DOI: 10.1038/s41586-023-06596-2 references this (Id 39641) publication
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Cavity-mediated thermal control of metal-to-insulator transition in 1T-TaS2
ROBIS: 37545 has used this (Id 39641) publication of HZDR-primary research data
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-09-24 Open access
DOI: 10.14278/rodare.3153
Versions: 10.14278/rodare.3154
License: CC-BY-4.0
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39641
Ab initio path integral Monte Carlo simulation of warm dense matter
Abstract
I present an overview of current ab initio path integral Monte Carlo (PIMC) capabilities to simulate warm dense matter and related extreme states. In the first part, I introduce the PIMC method and summarize recent developments for the uniform electron gas. In the second part, I show how emerging PIMC simulations of real systems such as warm dense hydrogen and beryllium allow for novel ways to interpret x-ray Thomson scattering (XRTS) measurements. This is demonstrated for an experimental dataset for strongly compressed beryllium measured at the National Ignition Facility (NIF).
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Invited lecture (Conferences)
Physics of nonideal plasmas (PNP), 16.-19.09.2024, Oxford, United Kingdom
Permalink: https://www.hzdr.de/publications/Publ-39640
Transient density-driven granular segregation dynamics in a rotating drum
Papapetrou, T. N.; Bieberle, M.; Barthel, F.; Hampel, U.; Lecrivain, G.
Abstract
The shearing of a particle bed composed of two or more species results in spontaneous
segregation. This poses problems in many industries, where the mixing of granules and powders
is a common process and a homogeneous product is desired. In this work, the segregation
dynamics occurring in a horizontal rotating drum filled with two granular species that only
differ in density is investigated. In this system, radial segregation is relatively fast and occurs
over the course of a few drum rotations. State-of-the art techniques allow the study of
segregation dynamics at the end walls of a drum, as well as the observation of slow axial
dynamics and the steady state of radial mixing inside the drum bulk. They do not allow,
however, continuous observation of the transient radial mixing in the bulk. Using the ultrafast
X-ray computer tomography it is possible to take cross-sectional images through the opaque
granular systems at 1000 frames per second. The high-speed image sequences from intermediate
planes of the drum can reveal the segregation dynamics in the bulk. Here we present
experimental results from the transient state of radial mixing for a binary granular system with
density difference (density ratio 2.8) and equal size (4 mm) spherical beads in a half-filled drum.
Using a dimensionless mixing index (M), we compare the dynamics of radial mixing and
segregation in transverse planes in the bulk of the drum, captured with UFXCT, with the
dynamics from the circular end caps to highlight wall effects. We also compare two dynamic
models for radial mixing and consider the effect of flow on mixing dynamics. We find that
second-order dynamics fit better the data than the commonly used first-order, since it accounts
for the overshooting mixing dynamics occurring at higher drum speeds. We also find that,
compared to the end cap, the dense particle segregation core is larger in the bulk plane and the
overshooting in the mixing index is smaller, suggesting a correlation between mixing and flow
characteristics, such as the dynamic angle of repose. Our results, because of better describing
overmixing, are highly relevant to the pharmaceutical, food and cement industrie
Involved research facilities
- ROFEX
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Lecture (Conference)
(Online presentation)
1st European Fluid Dynamics Conference, 16.-20.09.2024, Aachen, Germany
Permalink: https://www.hzdr.de/publications/Publ-39638
Investigating binary granular mixing in a rotating drum using ultrafast X-ray computed tomography
Papapetrou, T. N.; Bieberle, M.; Barthel, F.; Hampel, U.; Lecrivain, G.
Abstract
The transient mixing dynamics of an initially segregated binary granular system in a half-filled rotating drum are investigated. The granular system consists of spherical beads having identical size. The density ratio between the two granular phases is 2.8. With its ability to scan three-dimensional opaque systems with a high frequency, the ultrafast X-ray computed tomography is used to capture the transient and steady-state segregation dynamics in the bulk. The segregation dynamics are also compared to those at the circular end-wall caps, which have been captured with a camera. The results show an axial migration of the denser particles towards the bulk and, more importantly, second-order overshooting dynamics in the radial mixing index, which tend to increase with the Froude number. The results will find application in industrial systems, where rapid mixing occurs. We also believe the presented data can serve as validation for future three-dimensional simulations focusing on the transient formation of segregation patterns in the bulk.
Involved research facilities
- ROFEX
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Lecture (Conference)
16th International Conference on Gas–Liquid and Gas–Liquid–Solid Reactor Engineering, 02.-05.09.2024, Dresden, Germany
Permalink: https://www.hzdr.de/publications/Publ-39637
Terahertz magneto-optical sampling in quartz glass
Kovalev, S.; Ilyakov, I.; Reinold, A.; Pilch, P.; Zhu, C.; Ghalgaoui, A.; Salikhov, R.; Lindner, J.; Wang, Z.
Abstract
In this Letter, we demonstrate terahertz (THz) magnetic field detection in fused silica with sensitivity that can be easily controlled by sample tilting (for both amplitude and polarization). The proposed technique remains in the linear regime at magnetic fields exceeding 0.3 T (0.9 MV/cm of equivalent electric field) and allows the use of low-cost amorphous materials. Furthermore, the demonstrated effects should be present in a wide variety of materials used as substrates in different THz-pump laser–probe experiments and need to be considered in order to disentangle different contributions to the measured signals.
Keywords: Laser beams; Nonlinear optical crystals; Optical activity; Phase matching; Phase velocity; Sum frequency generation
Involved research facilities
- T-ELBE
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Optics Letters 49(2024)16, 4749-4752
DOI: 10.1364/OL.534475
Downloads
- Secondary publication expected from 15.08.2025
Permalink: https://www.hzdr.de/publications/Publ-39636
Origin of the metamagnetic transitions in Y0.9Tb0.1Fe2D4.3
Paul-Boncour, V.; Shtender, V.; Provost, K.; Phejar, M.; Cuevas, F.; Skourski, Y.; Isnard, O.
Abstract
Deuterium insertion was used to tune the magnetic properties of Y0.9Tb0.1Fe2 Laves phase towards an itinerant electron metamagnetic (IEM) behavior. The latter is highly sensitive to chemical changes and external parameters. The structural and magnetic properties of Y0.9Tb0.1Fe2D4.3 were investigated using various neutron powder diffraction experiments in addition to magnetic measurements under steady and pulsed high magnetic fields up to 60 T. The deuteride crystallizes in a monoclinic structure (Pc space group) with 4.3 D atoms located in 18 tetrahedral interstitial sites. At zero field, it undergoes a ferrimagnetic-antiferromagnetic (FiM-AFM) transition at TM0 = 90 K, accompanied by an anisotropic magnetostriction and a negative cell volume expansion of 0.6 %. A second AFM-PM transition is observed at 146 K. Under pulsed magnetic field at 4.2 K, the deuteride displays a multistep magnetic behavior from ferrimagnetic to a ferromagnetic state, which can be attributed to a stepwise rotation of the Tb moments. The ZFC-FC magnetization curves at low fields exhibit an irreversibility below 90 K, followed by a sharp decrease in magnetization at the FM-AFM transition. Between 90 K and 130 K, the magnetization curves display an IEM behavior, with the transition field increasing linearly with temperature.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Journal of Solid State Chemistry 338(2024), 124898
DOI: 10.1016/j.jssc.2024.124898
Permalink: https://www.hzdr.de/publications/Publ-39631
Role of competing magnetic anisotropies in deriving topologically nontrivial spin textures in oxide heterostructures
Sahoo, J.; Vagadia, M.; Hübner, R.; Bhatt, N.; Kumar, A.; Sahastrabuddhe, G.; Janay Choudhary, R.; Shankar Singh, R.; Rana, D. S.
Abstract
In spatially inverted systems, the complex entanglement of Dzyaloshinskii-Moriya interaction (DMI) and other magnetic anisotropies, mediated by spin-orbit coupling (SOC), influences the emergence and dynamics of the chiral spin textures such as skyrmion. The competing and unified effect of these anisotropies - which is expected to amplify the skyrmionics response in the quantum transport phenomena - is not yet known. Here, we investigate this template and engineer the topological Hall effect (THE) arising from chiral spin texture in a range of La0.7Sr0.3MnO3/CaIrO3 superlattices. The strength of SOC and interfacial DMI are controlled via the architectural design and charge transfer across the interface. All the superlattices display anomalous Hall effect, accompanied by the hump like feature. In (L3Iy)4 (y = 4, 6, and 8) superlattices, the humplike feature that is deemed as the THE is intrinsic in nature and stems from the chiral spin texture. For the intermediate strength of SOC, unique eightfold anisotropic magnetoresistance oscillations manifest owing to the modulation of the magnetic easy axis in the presence of competing anisotropies. For this superlattice, THE shows remarkable enhancement of the order such that it takes complete precedence over anomalous contribution. The thicker superlattice with higher fraction of charge transfer augments ferromagnetic interactions, and the artificial THE appears as a consequence of a dual-channel anomalous Hall effect. This manipulation of the THE is intricately connected to the concurrent presence of magnetic anisotropies, altering the dynamics of chiral spin texture. These findings expand the understanding of the corroborative contributions of competing anisotropies and yield a comprehensive control of chiral properties - a dimension for the utility in next-generation spintronics technologies.
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39630) publication
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Physical Review B 110(2024), 104422
DOI: 10.1103/PhysRevB.110.104422
Permalink: https://www.hzdr.de/publications/Publ-39630
Contrastive Self-Supervised Learning for Globally Distributed Landslide Detection
Ghorbanzadeh, O.; Shahabi, H.; Tavakkoli Piralilou, S.; Crivellari, A.; EC La Rosa, L.; Atzberger, C.; Li, J.; Ghamisi, P.
Abstract
The Remote Sensing (RS) field continuously grapples with the challenge of transforming satellite data into actionable information. This ongoing issue results in an ever-growing accumulation of unlabeled data, complicating interpretation efforts. The situation becomes even more challenging when satellite data must be used immediately to identify the effects of a natural hazard. Self-supervised learning (SSL) offers a promising approach for learning image representations without labeled data. Once trained, an SSL model can address various tasks with significantly reduced requirements for labeled data. Despite advancements in SSL models, particularly those using contrastive learning methods like MoCo, SimCLR, and SwAV, their potential remains largely unexplored in the context of instance segmentation and semantic segmentation of satellite imagery. This study integrates SwAV within an auto-encoder framework to detect landslides using deca-metric resolution multi-spectral images from the globally-distributed large-scale landslide4sense (L4S) 2022 benchmark dataset, employing only 1% and 10% of the labeled data. Our proposed SSL auto-encoder model features two modules: SwAV, which assigns features to prototype vectors to generate encoder codes, and ResNets, serving as the decoder for the downstream task. With just 1% of labeled data, our SSL model performs comparably to ten state-of-the-art deep learning segmentation models that utilize 100% of the labeled data in a fully supervised manner. With 10% of labeled data, our SSL model outperforms all ten fully supervised counterparts trained with 100% of the labeled data.
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IEEE Access 12(2024), 118453-118466
DOI: 10.1109/ACCESS.2024.3449447
Permalink: https://www.hzdr.de/publications/Publ-39626
Policies and Good Practice in Research Software Development at Helmholtz-Zentrum Dresden - Rossendorf e.V. (HZDR)
Hüser, C.; Huste, T.; Juckeland, G.; Konrad, U.
Abstract
Research software is a central pillar in the scientific work in general, in the Helmholtz Association and in particular at the Helmholtz-Zentrum Dresden - Rossendorf e.V. (HZDR). The software policy at the HZDR supports researchers in their independence and ability to act and is a framework that provides orientation. It gives advice and makes recommendations for the whole software lifecycle from development and documentation to publication and distribution as well as maintenance of the research software.
The HZDR software policy is derived from a model policy provided by the Task Group Research Software of the Helmholtz Open Science Office. Adaptations were made, for example, regarding the recommended software quality ensurance measures based on the software application classes suggested by the German Aerospace Center (DLR) as well as the choice of Open-Source Software (OSS) licenses. A selection process and decision tree were defined to recommend the preferred use a specific set of OSS licenses at the HZDR.
The introduction of a policy at HZDR and for each of the research centres in the Helmholtz Association involves not only behavioural but also cultural change in the whole research association and all related research groups. The overall objectives are to achieve better sustainability and higher quality in research software engineering leading to better verifiability, traceability and reproducibility of scientific results.
Keywords: SaxFDM Tagung 2024; Helmholtz Association; Software Policy
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Lecture (Conference)
5. SaxFDM-Tagung 2024 - Forschungsdatenmanagement in Sachsen (SaxFDM), 17.09.2024, TU Bergakademie Freiberg (TUBAF), Deutschland
DOI: 10.5281/zenodo.13808029
Permalink: https://www.hzdr.de/publications/Publ-39620
Quantum oscillation signatures of the Bloch-Grüneisen temperature in the Dirac semimetal ZrTe5
Galeski, S.; Araki, K.; Forslund, O. K.; Wawrzynczak, R.; Legg, H. F.; Sivakumar, P. K.; Miniotaite, U.; Elson, F.; Mansson, M.; Witteveen, C.; von Rohr, F. O.; Baron, A. Q. R.; Ishikawa, D.; Li, Q.; Gu, G.; Zhao, L. X.; Zhu, W. L.; Chen, G. F.; Wang, Y.; Parkin, S. S. P.; Gorbunov, D.; Zherlitsyn, S.; Vlaar, B.; Nguyen, D. H.; Paschen, S.; Narang, P.; Felser, C.; Wosnitza, J.; Meng, T.; Sassa, Y.; Hartnoll, S. A.; Gooth, J.
Abstract
The electron-phonon interaction is in many ways a solid state equivalent of quantum electrodynamics. Being always present, the e-p coupling is responsible for the intrinsic resistance of metals at finite temperatures, making it one of the most fundamental interactions present in solids. In typical metals, different regimes of e-p scattering are separated by a characteristic phonon energy scale—the Debye temperature. However, in metals harboring very small Fermi surfaces a new scale emerges—the Bloch-Grüneisen temperature. This is a temperature at which the average phonon momentum becomes comparable to the Fermi momentum of the electrons. Here we report sub-Kelvin transport and sound propagation experiments on the Dirac semimetal ZrTe5. The combination of the simple band structure with only a single small Fermi surface sheet allowed us to directly observe the Bloch-Grüneisen temperature and its consequences on electronic transport of a 3D metal in the limit where the small size of the Fermi surface leads to effective restoration of translational invariance of free space. Our results indicate that on entering this hydrodynamic transport regime, the viscosity of the Dirac electronic liquid undergoes an anomalous increase beyond the theoretically predicted T5 temperature dependence. Extension of our measurements to strong magnetic fields reveal that, despite the dimensional reduction of the electronic band structure, the electronic liquid retains characteristics of the zero-field hydrodynamic regime up to the quantum limit. This is vividly reflected by an anomalous suppression of the amplitude of quantum oscillations seen in the Shubnikov-de Haas effect.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review B 110(2024), L121103
DOI: 10.1103/PhysRevB.110.L121103
arXiv: https://arxiv.org/html/2309.10480v2
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39619
Magnon-phonon interactions in the spinel compound MnSc2Se4
Sourd, J.; Skourski, Y.; Prodan, L.; Tsurkan, V.; Miyata, A.; Wosnitza, J.; Zherlitsyn, S.
Abstract
We investigated the magnetic and magnetoelastic properties of MnSc2Se4 single crystals at low temperature under a magnetic field directed along the crystallographic [111] axis. The magnetization data at low temperature show a linear increase with magnetic field, until saturation is reached above 15 T. In ultrasound, a longitudinal acoustic mode shows a softening in field, which is absent for a transverse acoustic mode.We discuss these results using a microscopic model based on the framework of linear spin-wave theory. The magnetic and magnetoelastic data are qualitatively reproduced by considering magnon-phonon interactions arising from exchange-striction coupling between the crystal lattice and spin-wave fluctuations in the zero-temperature limit.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review B 110(2024), 094414
DOI: 10.1103/PhysRevB.110.094414
Downloads
- Secondary publication expected from 09.09.2025
Permalink: https://www.hzdr.de/publications/Publ-39617
Magnetic phase diagram of rouaite Cu2(OH)3NO3
Chakkingal, A. M.; Kulbakov, A. A.; Grumbach, J.; Pavlovskii, N. S.; Stockert, U.; Parui, K. K.; Avdeev, M.; Kumar, R.; Niwata, I.; Häußler, E.; Gumeniuk, R.; Stewart, J. R.; Tellam, J. P.; Pomjakushin, V.; Granovsky, S.; Doerr, M.; Hassinger, E.; Zherlitsyn, S.; Ihara, Y.; Inosov, D. S.; Peets, D. C.
Abstract
Spinon-magnon mixing was recently reported in botallackite Cu2(OH)3Br with a uniaxially compressed triangular lattice of Cu2+ quantum spins [H. Zhang et al., Phys. Rev. Lett. 125, 037204 (2020)]. Its nitrate counterpart rouaite, Cu2(OH)3NO3, has a highly analogous structure and might be expected to exhibit similar physics. To lay a foundation for research on this material, we clarify rouaite’s magnetic phase diagram and identify both low-field phases. The low-temperature magnetic state consists of alternating ferromagnetic and antiferromagnetic chains, as in botallackite, but with additional canting, leading to net moments on all chains which rotate from one chain to another to form a 90° cycloidal pattern. The higher-temperature phase is a helical modulation of this order, wherein the spins rotate from one Cu plane to the next. This extends to zero temperature for fields perpendicular to the chains, leading to a set of low-temperature field-induced phase transitions. Rouaite may offer another platform for spinon-magnon mixing, while our results suggest a delicate balance of interactions and high tunability of the magnetism.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review B 110(2024), 054442
DOI: 10.1103/PhysRevB.110.054442
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Permalink: https://www.hzdr.de/publications/Publ-39616
Excitation spectrum and spin Hamiltonian of the frustrated quantum Ising magnet Pr3BWO9
Nagl, J.; Flavián, D.; Hayashida, S.; Povarov, K.; Yan, M.; Murai, N.; Ohira-Kawamura, S.; Simutis, G.; Hicken, T. J.; Luetkens, H.; Baines, C.; Hauspurg, A.; Schwarze, B. V.; Husstedt, F.; Pomjakushin, V.; Fenell, T.; Yan, Z.; Gvasaliya, S.; Zheludev, A.
Abstract
We present a thorough experimental investigation on single crystals of the rare-earth based frustrated quantum antiferromagnet Pr3BWO9, a purported spin-liquid candidate on the breathing kagome lattice. This material possesses a disordered ground state with an unusual excitation spectrum involving a coexistence of sharp spin waves and broad continuum excitations. Nevertheless, we show through a combination of thermodynamic, magnetometric, and spectroscopic probes with detailed theoretical modeling that it should be understood in a completely different framework. The crystal field splits the lowest quasidoublet states into two singlets moderately coupled through frustrated superexchange, resulting in a simple effective Hamiltonian of an Ising model in a transverse magnetic field. While our neutron spectroscopy data do point to significant correlations within the kagome planes, the dominant interactions are out-of-plane, forming frustrated triangular spin-tubes through two competing ferro-antiferromagnetic bonds. The resulting ground state is a simple quantum paramagnet, where the presence of strongly hyperfine-coupled nuclear moments and weak structural disorder causes significant modifications to both thermodynamic and dynamic properties.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Physical Review Research 6(2024), 023267
DOI: 10.1103/PhysRevResearch.6.023267
Permalink: https://www.hzdr.de/publications/Publ-39615
Large-scale modeling of high-energy-density plasmas from first principles: Dynamic Density Response Properties
Abstract
Recent promising results from inertial fusion energy (IFE) facilities, such as the National Ignition Facility in the USA, have sparked a strong interest in IFE technologies. Because it is a multiscaled problem from a simulation standpoint, significant effort is required to accurately model the dense plasmas on various length and time scales, which is crucial for developing IFE technology. One of the main challenges in modeling is creating reliable simulation tools to study the dynamic dielectric and transport properties of dense plasmas across different temperature and density ranges. Quantum many-body theory is crucial in developing a dependable method for computing these properties, provided the density response function of plasmas is known. This presentation discusses the advanced simulation methods being used and developed at the Center of Advanced Systems Understanding [1-4] for this property and the associated computational and work expenses.
[1] Tobias Dornheim, Zhandos A. Moldabekov, Kushal Ramakrishna, Panagiotis Tolias, Andrew D. Baczewski, Dominik Kraus, Thomas R. Preston, David A. Chapman, Maximilian P. Böhme, Tilo Döppner, Frank Graziani, Michael Bonitz, Attila Cangi, Jan Vorberger, Electronic density response of warm dense matter, Phys. Plasmas 30, 032705 (2023).
[2] Zhandos Moldabekov, Jan Vorberger, Tobias Dornheim, Density Functional Theory Perspective on the Nonlinear Response of Correlated Electrons across Temperature Regimes, J. Chem. Theory Comput. 2022, 18, 5, 2900–2912
[3] Zhandos A. Moldabekov, Michele Pavanello, Maximilian P. Böhme, Jan Vorberger, and Tobias Dornheim, Linear-response time-dependent density functional theory approach to warm dense matter with adiabatic exchange-correlation kernels, Phys. Rev. Research 5, 023089 (2023)
[4] Maximilian Böhme, Zhandos A. Moldabekov, Jan Vorberger, and Tobias Dornheim, Static Electronic Density Response of Warm Dense Hydrogen: Ab Initio Path Integral Monte Carlo Simulations, Phys. Rev. Lett. 129, 066402 (2022)
Keywords: warm dense matter; dynamic dielectric and transport properties
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Invited lecture (Conferences)
The 10th annual meeting of the Matter and Technologies, 18.-20.09.2024, the Humboldt University of Berlin, Germany
Permalink: https://www.hzdr.de/publications/Publ-39612
Thermal boundary layer dynamics in low-Prandtl-number Rayleigh–Bénard convection
Kim, N.; Schindler, F.; Vogt, T.; Eckert, S.
Abstract
In this experimental study, we explore the dynamics of the thermal boundary layer in liquid metal Rayleigh–Bénard convection, covering the parameter ranges of 0.026 ≤ Prandtl numbers (Pr) ≤0.033 and Rayleigh numbers (Ra) up to 2.9×10^9. Our research focuses on characterising the thermal boundary layer near the top plate of a cylindrical convection cell with an aspect ratio of 0.5, distinguishing between two distinct regions: the shear-dominated region around the centre of the top plate and a location near the side wall where the boundary layer is expected to be affected by the impact or ejection of thermal plumes. The dependencies of the boundary layer thickness on Ra at these positions reveal deviating scaling exponents with the difference diminishing as Ra increases. We find stronger fluctuations in the boundary layer and increasing deviation from the Prandtl–Blasius–Pohlhausen profile with increasing Ra, as well as in the measurements outside the centre region. Our data illustrate the complex interplay between flow dynamics and thermal transport in low-Pr convection.
Keywords: Bénard convection; plumes/thermals; boundary layer structure
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Journal of Fluid Mechanics 994(2024), A4
DOI: 10.1017/jfm.2024.629
Permalink: https://www.hzdr.de/publications/Publ-39611
Enhanced Cryogenic Magnetocaloric Effect from 4f-3d Exchange Interaction in B-Site Ordered Gd2CuTiO6 Double Perovskite Oxide
Zhang, Y.; Na, Y.; Hao, W.; Gottschall, T.; Li, L.
Abstract
Magnetic refrigeration based on the principle of the magnetocaloric effect (MCE) in magnetic solids has been considered as a prospective cooling technology. Exploring suitable magnetocaloric materials (MCMs) is a vital prerequisite for practical applications. Herein, an excellent cryogenic MCM—the B-site-ordered Gd2CuTiO6 double perovskite (DP) oxide—which exhibits the largest MCE among known Gd-based DP oxides, is identified. Such enhanced cryogenic MCE in the Gd2CuTiO6 DP oxide likely stems from the exchange interaction effect between Gd-4f and Cu-3d magnetic sublattices. Under a magnetic field change of 0–7 T, the maximum magnetic entropy change (−ΔST
max) of the Gd2CuTiO6 DP oxide reaches 51.4 J kg−1 K−1 (378.2 mJ cm−3 K−1), which is much larger than that of the commercialized magnetic refrigerant Gd3Ga5O12, which is 38.3 J kg−1 K−1 (271.2 mJ cm−3 K−1), and it is also superior to most of the recently reported benchmarked cryogenic MCMs, indicating the possibility for practical applications. This work also provides a productive route for future cryogenic MCM design by harnessing 4f–3d exchange interactions.
Involved research facilities
- High Magnetic Field Laboratory (HLD)
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Advanced Functional Materials (2024), 2409061
DOI: 10.1002/adfm.202409061
Cited 11 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39609
Heat flow data from the fungus Schizophyllum commune
Fahmy, K.; Günther, A.; Bertheau, R.; Pape, D.
Abstract
The data set contains three typical heat flow curves recorded from the fungus Schizophyllum commune and exemplifies the evaluation of such data by the software tool metabolator (https://doi.org/10.14278/rodare.3049).
Keywords: microcalorimetry; Monod; metabolism; fermentation; glycolysis; aerobic; anaerobic; metabolator
Related publications
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METABOLATOR: Analysis of Microcalorimetric Metabolic Data Using Monod's Equation
RODARE: 3049 is supplemented by this (Id 39608) publication
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-09-19 Open access
DOI: 10.14278/rodare.3151
Versions: 10.14278/rodare.3152
License: CC-BY-4.0
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39608
Cascading ion acceleration in the relativistic transparency regime driven by ultra-intense PW lasers
Ziegler, T.; Göthel, I.; Dover, N. P.; Kluge, T.; Kroll, F.; Metzkes-Ng, J.; Nishiuchi, M.; Püschel, T.; Reimold, M.; Umlandt, M. E. P.; Vescovi Pinochet, M. A.; Schramm, U.; Zeil, K.
Abstract
Laser-driven ion accelerators can produce pulsed multi-MeV beams with high-peak currents, which can be used for multidisciplinary applications, including radiotherapy, injectors for advanced accelerator concepts, neutron production and fast ignition in inertial confinement fusion. However, the evolution from complex physics experiments to turnkey particle sources for applications requires breakthroughs in the generated beam parameters, their robustness and scalability to higher repetition rates and efficiencies.
Previous research has shown enhanced acceleration performance when the laser main pulse arrival coincides with the onset of relativistically induced transparency (RIT) of the target. In a series of experiments, using the DRACO-PW and the J-KAREN-P laser system, we scanned laser and target parameters to identify optimal interaction conditions for ion acceleration in the RIT regime [1]. Our results demonstrate the immense potential of this regime by accelerating protons to a record energy of 150MeV using only 22J laser energy [2]. The proton beam featured a high-energy component with low divergence, which is spectrally and spatially separated. Target transparency was identified as a simple control parameter for determining the high-performance domain owing to its sensitivity to subtle changes in the initial laser–target conditions. Start-to-end simulations validate these results and elucidate the role of preceding laser light in pre-expanding the target along with the detailed acceleration dynamics during the main pulse interaction. The insights into the role of the ultrashort pulse duration and the temporal contrast of the laser represent a significant step forward in understanding and controlling ion acceleration in the RIT regime.
Involved research facilities
- Draco
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Invited lecture (Conferences)
ICUIL 2024, 09.-13.09.2024, Cozumel, Mexiko
Permalink: https://www.hzdr.de/publications/Publ-39607
A disposal-MOX concept for plutonium disposition
Cole, M. R.; Blackburn, L. R.; Haigh, L. T.; Bailey, D. J.; Townsend, L. T.; Kvashnina, K.; Hyatt, N. C.; Corkhill, C. L.
Abstract
In case it is desirable to dispose of inventories of separated civil PuO2 that have no further use, a
suitable immobilisation matrix is required, prior to disposition in a geological disposal facility. Conversion
of Pu into a mixed oxide (MOX)-type material with characteristics suitable for disposal has previously
been suggested, but not yet demonstrated at laboratory or industrial scale. We here demonstrate the
feasibility of different synthesis routes for simulant ‘‘disposal-MOX’’, using Th 4+ as a Pu4+ surrogate and
containing Gd3+ in a suitable quantity to ensure criticality control. Compositions of (U(1(x+y))ThxGdy)O2d,
where x = 0.1, 0.2 and x : y = 10 : 1 or 100 : 1, were synthesised by a solid state route mimicking the industrial
MIMAS MOX fuel fabrication process, or through an oxalic wet co-precipitation
method. Both synthesis routes gave a single phase fluorite structure upon heat-treatment at 1700 1C, with a
grain size similar to (Pu,U)O2 MOX fuel. The relative density of the sintered pellets was 490% but was
highest in co-precipitated materials, with Th4+ and Gd3+ additions more homogenously distributed. Though
no unincorporated ThO2 or Gd2O3 was observed in any sample, Th and Gd-rich regions were more
prevalent in materials produced through solid state synthesis, in accordance with MIMAS MOX fuel
microstructures. The incorporation of Gd3+ within the fluorite lattice, which is favourable from a criticality
control perspective in a Pu wasteform, was found to be charge balanced via the generation of oxygen
vacancy defects, but not U5+. These results demonstrate feasible synthesis routes for a disposal-MOX
wasteform product via both solid state and wet co-precipitation fabrication routes.
Involved research facilities
- Rossendorf Beamline at ESRF DOI: 10.1107/S1600577520014265
Related publications
- DOI: 10.1107/S1600577520014265 is cited by this (Id 39606) publication
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Materials Advances 5(2024), 6416
DOI: 10.1039/d4ma00420e
Permalink: https://www.hzdr.de/publications/Publ-39606
Data publication: Formation of martensitic microstructure in epitaxial Ni-Mn-Ga films after fast cooling
Ge, Y.; Ganss, F.; Lünser, K.; Kar, S.; Hübner, R.; Zhou, S.; Rebohle, L.; Fähler, S.
Abstract
Raw data for the publication titled 'Formation of martensitic microstructure in epitaxial Ni-Mn-Ga films after fast cooling' done by Yuru Ge (FWIN-HZDR) and the colleagues. The order of the figures follows the latest manuscript version before submission, labeled "v13".
Keywords: Ni-Mn-Ga thin film; epitaxial growth; martensitic transformation; microstructure; flash lamp annealing
Involved research facilities
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
Related publications
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39605) publication
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Reseach data in the HZDR data repository RODARE
Publication date: 2024-09-18 Open access
DOI: 10.14278/rodare.3134
Versions: 10.14278/rodare.3135
License: CC-BY-4.0
Downloads
Permalink: https://www.hzdr.de/publications/Publ-39605
Positron annihilation spectroscopy as a probe of defect microstructure in heavily doped semiconductors
Liedke, M. O.; Prucnal, S.; Butterling, M.; Shaikh, M. S.; Steuer, O.; Maffei, R. M.; Zhou, S.; Wagner, A.
Abstract
Positron annihilation spectroscopy (PAS) is a precise probe of point defects in bulk and nanomaterials, such as semiconductors. Positrons localize in the neutral and negatively charged open volume defects, i.e. vacancies and their agglomerations, extended defects or pores. The time to the inevitable annihilation of the positron with the electron depends on the local electron density and scales with the open volume size. Positrons pre-accelerated to a given kinetic energy are implanted into solids, allowing depth profiling. In a defect, their lifetime increases and the energetics of the annihilation photons changes. These characteristics are measured using two main measurement techniques, namely positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler broadening spectroscopy (cDBS or cDB-PAS), respectively. Both techniques are available at the large-scale user facility ELBE at HZDR, Germany. PALS allows the evaluation of defect size and concentration, while cDBS provides sensitivity to positron annihilation with valence and core electrons, the latter a fingerprint of the nearest neighbor atoms.
This contribution discusses the role of open volume defects and defect chemistry in the context of heavily doped semiconductors, such as sulfur- and telluride-doped GaAs [1] and Si [2], Al doped ZnO (AZO) [3], or pulsed laser and flash lamp annealed GeSn [4]. We will show that incomplete recrystallization processes resulting from intense pulsed laser melting (PLM) and flash lamp annealing (FLA) are related to defect distribution and electrical activation efficiency in chalcogenide-implanted GaAs. Similarly, in thermally treated chalcogenide-implanted Si, vacancy accumulation processes correlate with variations in carrier concentration and electron mobility. A combination of PAS measurements and DFT calculations allows to translate the experimental results into defect types/sizes and highlights the role of vacancy-dopant complexes for electrical deactivation. On the other hand, the relationship between the crystal quality of AZO films, i.e. single, polycrystalline or amorphous structures, and deposition parameters, such as growth pressure and thickness, can be related to the concomitant increase in vacancy agglomeration size and density. We will discuss the role of dislocations and Sn-decorated germanium vacancies, resulting from Sn diffusion and clustering due to PLM, on the electrical properties of GeSn. The change in defect microstructure depending on the Sn content will be highlighted, too. Finally, a new perspective for PAS is given, where the simultaneous light illumination together with positron measurements will allow new insights into sub-bandgap defect levels in semiconductors, e.g. in GaN.
[1] J. Duan et al., J. Appl. Phys., 134 (2023) 95102
[2] M.S. Shaikh et al., Appl. Surf. Sci., 567 (2021) 150755
[3] R.M. Maffei et al., Appl. Surf. Sci., 665 (2024) 160240
[4] O. Steuer et al., J. Phys. Condens. Matter, 36 (2024) 085701
Keywords: positron annihilation spectroscopy; hyperdoped semiconductors; GaAs; Si; GeSn
Involved research facilities
- Radiation Source ELBE DOI: 10.17815/jlsrf-2-58
- Ion Beam Center DOI: 10.17815/jlsrf-3-159
- P-ELBE
Related publications
- DOI: 10.17815/jlsrf-2-58 is cited by this (Id 39604) publication
- DOI: 10.17815/jlsrf-3-159 is cited by this (Id 39604) publication
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Invited lecture (Conferences)
Fall Meeting of the European Materials Research Society (E-MRS), 16.-19.09.2024, Warsaw, Poland
Permalink: https://www.hzdr.de/publications/Publ-39604
Thionitrosyl Complexes of Rhenium and Technetium with PPh₃ and Chelating Ligands—Synthesis and Reactivity
Nowak, D.; Hagenbach, A.; Sawallisch, T. E.; Abram, U.
Abstract
In contrast to corresponding nitrosyl compounds, thionitrosyl complexes of rhenium and technetium are rare. Synthetic access to the thionitrosyl core is possible by two main approaches: (i) the treatment of corresponding nitrido complexes with S₂C₂ and (ii) by reaction of halide complexes with trithiazyl chloride. The first synthetic route was applied for the synthesis of novel rhenium and technetium thionitrosyls with the metals in their oxidation states “+1” and “+2”. [MᵛNCl₂(PPh₃)₂], [MᵛNCl(PPh₃)(LOMe)] and [MᵛᶦNCl₂(LOMe)] (M = Re, Tc; {LOMe}⁻ = (η⁵-cyclopentadienyl)tris(dimethyl phosphito-P)cobaltate(III)) complexes have been used as starting materials for the synthesis of [Reᴵᴵ(NS)Cl₃(PPh₃)₂] (1), [Reᴵᴵ(NS)Cl₃(PPh₃)(OPPh₃)] (2), [Reᴵᴵ(NS)Cl(PPh₃)(LOMe)]⁺ (4a), [Reᴵᴵ(NS)Cl₂(LOMe)] (5a), [Tcᴵᴵ(NS)Cl(PPh₃)(LOMe)]⁺ (4b) and [Tcᴵᴵ(NS)Cl₂(LOMe)] (5b). The triphenylphosphine complex 1 is partially suitable as a precursor for ongoing ligand exchange reactions and has been used for the synthesis of [Reᴵ(NS)(PPh₃)(Et₂btu)₂] (3a) (HEt₂btu = N,N-diethyl-N′-benzoyl thiourea) containing two chelating benzoyl thioureato ligands. The novel compounds have been isolated in crystalline form and studied by X-ray diffraction and spectroscopic methods including IR, NMR and EPR spectroscopy and (where possible) mass spectrometry. A comparison of structurally related rhenium and technetium complexes allows for conclusions about similarities and differences in stability, reaction kinetics and redox behavior between these 4d and 5d transition metals.
Keywords: rhenium; technetium; thionitrosyl complexes; synthesis; X-ray diffraction; EPR; NMR
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Inorganics 12(2024)8, 210
DOI: 10.3390/inorganics12080210
Cited 1 times in Scopus
Permalink: https://www.hzdr.de/publications/Publ-39603
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