Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

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43795 Publications

A novel approach towards robust construction of physical colors on lithium niobate crystal

Yang, Q.; Yu, M.; Chen, Z.; Ai, S.; Kentsch, U.; Zhou, S.; Jia, Y.; Chen, F.; Liu, H.

Abstract

Controlling the construction of physical colors on the surfaces of transparent dielectric crystals is crucial for surface coloration and anti-counterfeiting applications. In this study, we present a novel approach to creating stable physical colors on the surface of lithium niobate crystals by combining gold ion implantation with laser direct writing technologies. The interaction between the laser, the implanted gold nanoparticles, and the crystal lattice induces permanent, localized modifications on the crystal surface. By fine-tuning the laser direct writing parameters, we reshaped the gold nanoparticles into spheres of varying sizes on the crystal surface, resulting in the display of red, green, blue, and pale-yellow colors. We investigated the influence of the implanted Au nanoparticles—particularly their localized surface plasmon resonances—on the modifications of the lithium niobate crystal lattice during the laser writing process using confocal Raman spectroscopy and high-resolution transmission electron microscopy. Our findings reveal that the embedded Au nanoparticles play a pivotal role in altering the conventional light-matter interaction between the crystal lattice and the laser, thereby facilitating the generation of surface colors. This work opens new avenues for the development of vibrant surface colors on transparent dielectric crystals.

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Permalink: https://www.hzdr.de/publications/Publ-41232


Kompetenzvermittlung bei der Entwicklung von Daten-strukturen durch intuitive Bearbeitung von RDF-Graphdaten

Steinmeier, L.

Abstract

Das Management von Forschungsdaten (FDM) ist ein wichtiger Aspekt moderner wissenschaftlicher Forschung, und das Resource Description Framework (RDF) hat sich als Standard für die Modellierung und -integration von Graphdaten etabliert. Die Komplexität von RDF und den damit verbundenen Ontologien kann jedoch ein Hindernis für die Akzeptanz darstellen, insbesondere für diejenigen, die keine umfassende Ausbildung in semantischen Webtechnologien haben. Um diese Herausforderung zu bewältigen, entwickeln wir Graduate, ein Software-Tool, mit dem Benutzer:innen RDF-Graphdaten in einer benutzerfreundlichen, grafischen Oberfläche erstellen können.

Graduate bietet eine intuitive visuelle Darstellung von RDF-Graphdaten als editierbares Diagramm, mit dem Benutzer:innen RDF-Tripel mit minimalem Schulungsaufwand erstellen und ändern können. Die Software unterstützt die Verwendung von Begriffen aus Ontologien und ermöglicht es den Benutzer:innen, reichhaltige, strukturierte Daten zu erstellen, die den etablierten Standards entsprechen.

Graduate hat ein erhebliches Potenzial für die Kompetenzvermittlung in Lehre und Forschung. Die visuelle Darstellung von RDF-Graphdaten bietet eine greifbare, intuitive Möglichkeit, komplexe Datenstrukturen zu verstehen und sich damit auseinanderzusetzen, und senkt die Einstiegshürden für Forschende und Studierende, die mit dem Konzept von Graphdaten und Ontologien nicht vertraut sind. Die Software kann auch als Lehrmittel dienen, das es Lehrkräften ermöglicht, die Prinzipien der ontologiebasierten Datenmodellierung auf praktische und interaktive Weise zu demonstrieren.

Darüber hinaus unterstützt Graduate über GitLab die Versionierung, gemeinsame Nutzung und kollaborative Arbeit an Graphendatensätzen. Dies kann die interdisziplinäre Forschung und Zusammenarbeit erleichtern und ermöglicht es Forschenden, gemeinsam an Datensätzen zu arbeiten und ihre Ergebnisse mit einem größeren Publikum zu teilen. Die Integration der Software in GitLab ermöglicht es Forschenden außerdem, Änderungen über die Versionskontrolle zu verfolgen und so die Reproduzierbarkeit und Transparenz ihrer Forschung zu verbessern.

Zusammenfassend lässt sich sagen, dass Graduate einen bedeutenden Fortschritt in der RDM-Technologie darstellt und eine benutzerfreundliche Schnittstelle für die Erstellung und Verwaltung von RDF-Graphdaten bietet. Die visuelle Darstellung von RDF-Daten in der Software bietet eine intuitive Möglichkeit, komplexe Datenstrukturen zu verstehen und sich mit ihnen auseinanderzusetzen, was den Kompetenztransfer in Lehre und Forschung unterstützt.

  • Open Access Logo Poster
    5. SaxFDM-Tagung, 17.09.2024, Freiberg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-41225


Graduate - An intuitive user interface for modeling semantic graph data

Steinmeier, L.

Abstract

Research data management (RDM) is an important aspect of modern scientific research, which is heavily relying on interconnected data sets and corresponding metadata. For modeling and integrating these interconnections and metadata, the Resource Description Framework (RDF) has often been proposed as a standard, since it has been in use by search engines and knowledge management systems for decades by now.

The RDF provides a graph data structure for enriched vocabularies, so-called ontologies, and therein expressed information. However, the complexity of RDF and ontologies can be a barrier to adoption, especially for those without extensive training. To overcome this challenge, we are developing Graduate, a software tool that allows users to create RDF graph data in a user-friendly, graphical interface.

Graduate provides an intuitive visual representation of RDF graph data as an editable diagram, allowing users to create and modify RDF triples with minimal training. The software supports the use of terms from ontologies and enables users to create rich, structured data that conforms to established standards.

In addition it allows for versioning, sharing and collaborative work on graph datasets via GitLab. This can facilitate interdisciplinary research and collaboration, allowing researchers to work together on datasets and share their findings with a wider audience. The software's integration with GitLab also allows researchers to track changes via version control, improving the reproducibility and transparency of their research.

In summary, Graduate represents a significant advance in RDM technology and provides a user-friendly interface for the creation and management of RDF graph data. The visual representation of RDF data in the software provides an intuitive way to understand and engage with complex data structures, supporting knowledge transfer in teaching and research.

Keywords: semantic; graph data; RDF; user interface

  • Open Access Logo Poster (Online presentation)
    Helmholtz Metadata Collaboration Conference 2024, 04.-06.11.2024, online, online

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Permalink: https://www.hzdr.de/publications/Publ-41224


Exploring Cluster Formation in Uranium Oxidation using High Resolution X-ray Spectroscopy at Elevated Temperatures

Bazarkina, E. F.; Bauters, S.; Watier, Y.; Weiss, S.; Butorin, S. M.; Kvashnina, K.

Abstract

Uranium dioxide (UO2) is a complex material with significant relevance to nuclear energy, materials science, and fundamental research. Understanding its high-temperature behavior is crucial for developing new uranium-based materials and improving nuclear fuel efficiency in nuclear reactors. Here we study the evolution of uranium state during the oxidation of UO2 in air at temperatures up to 550°C using the in-situ X-ray absorption spectroscopy in high energy resolution fluorescence detection mode at the U M4 edge, combined with electronic structure calculations. Our data reveal a complex sequence of events occurring over minutes and hours at elevated temperatures, including changes in the electronic and local structure, 5f electron occupancy, the formation of U cuboctahedral clusters, and the creation of U4O9 and U3O7 mixed U oxide phases. These findings highlight the fundamental role of clustering processes and pentavalent uranium in both the oxidation process and the stabilization of uranium materials

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Permalink: https://www.hzdr.de/publications/Publ-41219


Local structure modification around Si atoms in Si-implanted monocrystalline β-Ga₂O₃ (100) under heated substrate conditions

Demchenko, I. N.; Syryanyy, Y.; Shokri, A.; Melikhov, Y.; Domagała, J.; Minikayev, R.; Derkachova, A.; Munnik, F.; Kentsch, U.; Zając, M.; Reck, A.; Haufe, N.; Galazka, Z.

Abstract

Doping of β-Ga2O3 (100) with Si by ion implantation onto heated substrates is investigated. The study reveals complex ion beam-induced defect processes in β-Ga2O3, characterized by the formation of various defect types and their temperature-dependent transformation. By employing X-Ray Diffraction, Rutherford Backscattering Spectrometry, Particle-Induced X-Ray Emission, X-ray Absorption Near Edge Structure Spectroscopy, Transmission Electron Microscopy, and Density Functional Theory analyses, we examine lattice deformation, identify the local environment of dopants, assess electronic structure modifications, and verify the presence of extended defects induced by ion implantation. Our findings highlight the predominant contribution of substitutional and interstitial Si ions incorporated into complexes that act as donors manifesting n-type conductivity, while some fraction of the defects form complexes that act as traps for charge carriers. Notably, no monoclinic phase transformations were observed during implantation despite substrate temperature variations from 300 to 800°C.

Keywords: β-Ga2O3; WBG; implantation; XRD; RBS/PIXE/c; XANES; TEM; DFT; FMS

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Permalink: https://www.hzdr.de/publications/Publ-41216


Data publication: Beam arrival time data and LLRF performace data measured during Carrier-Suppression-Interferometer (CSI) test

Zenker, K.; Kuntzsch, M.; Hoffmann, M.; Schmidt, C.; Szczepanski, B.

Abstract

This data was collected during ELBE AP #25103679: Continue Application Tests of the Carrier-Suppression-Interferometer (CSI) in CW-mode at ELBE to improve the Low-Level RF System Performance

Keywords: LLRF; BAM

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Permalink: https://www.hzdr.de/publications/Publ-41215


Data publication: Simple THz phase retarder based on Mach-Zehnder interferometer for polarization control

Ueda, H.; Pashkin, O.; Uykur, E.; Helm, M.; Winnerl, S.

Abstract

Origin file with the original plots of the THz polarization state and FEL spectra

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Permalink: https://www.hzdr.de/publications/Publ-41214


Simple THz phase retarder based on Mach-Zehnder interferometer for polarization control

Ueda, H.; Pashkin, O.; Uykur, E.; Helm, M.; Winnerl, S.

Abstract

On-demand polarization control of electromagnetic waves is the fundamental element of modern optics. Its interest has recently been expanded in the terahertz (THz) range for coherent excitation of collective quasiparticles in matters, triggering a wide variety of non-trivial intriguing physics, e.g., anharmonicity, nonlinear coupling, and metastability. Wavelength tunability in THz polarization control is fundamentally important for the resonant excitation of collective modes. Here, we propose and demonstrate a simple and convenient THz phase retarder based on the Mach-Zehnder interferometer to obtain circular polarization. The efficiency of THz polarization conversion is demonstrated by the achieved high polarization degree of more than 99.9% and a large transmission of ~76%. The simple setup allows us to adapt the phase retarder to existing setups readily and will contribute to further exploration of ultrafast science, e.g., chiral phononics.

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Permalink: https://www.hzdr.de/publications/Publ-41213


Magnetoelectronics for magnetically aware soft-bodied robots

Makarov, D.

Abstract

Motion sensing is the primary task in numerous disciplines including industrial and soft robotics, prosthetics, virtual and augmented reality appliances. In rigid electronics, rotations, displacements and vibrations are typically monitored using magnetic field sensors. Here, we will discuss on the fabrication of flexible, stretchable and printable magnetoelectronic devices. The technology platform relies on high-performance magnetoresistive and Hall effect sensors either deposited or printed on polymeric foils. These skin conformal flexible and printable magnetosensitive elements enable touchless interactivity with surroundings based on the interaction with magnetic fields. This is relevant for soft robotics [1] and human-machine interfaces based on smart skins [2-4] and smart wearables [5]. In particular, reconfigurable magnetic origami actuators [1] can be equipped with ultrathin and lightweight magnetosensitive e-skins [6], 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 [7]. Magnetic soft robots can be designed to perform complex collaborative tasks being driven using magnetic far fields [1] and near fields [8]. The use of magnetic near fields of on-board electromagnetic coils to drive embedded permanent magnets can provide the demanded tuneability to the mechanical strength of grippers working with objects of different stiffness including biological tissues [9]. Furthermore, we will introduce printed magnetic field sensors that can be flexible [10], stretchable [4], and capable of detection in a broad range of magnetic fields. By an appropriate choice of the polymeric binder, these solution processable magnetoelectronics can self-heal upon mechanical damage [11]. This research motivates further explorations towards the realisation of eco-sustainable magnetoelectronics. To this end, we will discuss biocompatible and biodegradable magnetosensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants and health monitoring.

[1] M. Ha et al., Reconfigurable magnetic origami actuators with on-board sensing for guided assembly. Adv. Mater. 33, 2008751 (2021).
[2] G. Canon et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoreception and interactive electronics. Nature Electr. 1, 589 (2018).
[3] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Comm. 10, 4405 (2019).
[4] M. Ha et al., Printable and stretchable giant magnetoresistive sensors for highly compliant and skin-conformal electronics. Adv. Mater. 33, 2005521 (2021).
[5] P. Makushko et al., Flexible magnetoreceptor with tunable Intrinsic logic for on-skin touchless human-machine interfaces. Adv. Funct. Mat. 31, 2101089 (2021).
[6] G. Canon et al., Magnetosensitive e-skins for interactive devices. Adv. Funct. Mater. (Review) 31, 2007788 (2021).
[7] 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).
[8] M. Richter et al., Locally addressable energy efficient actuation of magnetic soft actuator array systems. Adv. Sci. 2302077 (2023).
[9] L. Masjosthusmann et al., Miniaturized Variable Stiffness Gripper Locally Actuated by Magnetic Fields. Adv. Intel. Syst. 2400037 (2024).
[10] 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).
[11] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Comm. 13, 6587 (2022).

Keywords: magnetic composites; flexible magnetic field sensors; printed magnetic field sensors

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  • Invited lecture (Conferences)
    Materials Research Society (MRS) Spring Meeting 2025, 07.-11.04.2025, Seattle, USA

Permalink: https://www.hzdr.de/publications/Publ-41211


µCT data of Opalinus Clay samples (argillaceous and sandy facies) from Mont Terri, Switzerland

Kulenkampff, J.
Project Leader: Fischer, Cornelius; Researcher: Bollermann, Till

Abstract

9 Opalinus Clay samples, both from the argillaceous and from the sandy facies, scanned with the microfocus CT-scanner (µCT) Nikon XT H 225 at HZDR FWOT, including drill cores and cuttings (preparation remnants).

The voxel size (ca. resolution) is between 10 µm and 100 µm.

All tomograms were stored as 3D-blocks with unsigned 16-bit integers of uncalibrated gray levels. The voxel size and dimensions are given in the file name.

See data description in pdf-document OPA_uCT.pdf

Raw data availability on request:

CT-projections (\\gssnas\bigdata\FWOT_Img\CT_raw)

CT-reconstructions (\\lpzfiler01\geopet\GeoCT)

Avizo projects (HZDR archive)

Keywords: X-ray computed tomography; argillaceous rock; Opalinus Clay; drill core

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Permalink: https://www.hzdr.de/publications/Publ-41207


Coupled dissolution and clogging processes alter the fluid flow field in sandstones beyond the pore scale - PET and µCT data

Kulenkampff, J.; Schabernack, J.; Fischer, C.
DataCollector: Lösel, Dagmar; DataCollector: Schößler, Claudia; Researcher: Raj, Abhishek

Abstract

Data on a tomographic study of leaching processes on a Berea sandstone as supplemental information of the publication "Coupled dissolution and clogging processes alter the fluid flow field in sandstones beyond the pore scale" by Jonas Schabernack, Johannes Kulenkampff, and Cornelius Fischer, to be submitted to Earth and Planetary Science Letters (https://www.sciencedirect.com/journal/earth-and-planetary-science-letters).

The data consists of 

  1. BA6_312h_Concentration_65x65x66x40_double.raw: Time dependent activity concentrations (MBq/voxel) derived from 40 PET frames with frame length = 300 s, voxel size = 1.15 mm, measurement after a leaching period of 312h. Format: 4D-array of double, x=1:65, y=1:65, z=1:66, t:1:40.
  2. BA6_1320h_Concentration_65x65x61x40_double.raw: Time dependent activity concentrations (MBq/voxel) derived from 40 PET frames with frame length = 300 s, voxel size = 1.15 mm, measurement after a leaching period of 1320h. Format: 4D-array of double, x=1:65, y=1:65, z=1:61, t:1:40.
  3. BA6_312h_Flow Rate_65x65x66x1_double.raw: Magnitude of flow rate (mm3/s) from flowfield reconstruction of 1. Format: 3D-array of double, x=1:65, y=1:65, z=1:66.
  4. BA6_1320h_Flow Rate_65x65x61x1_double.raw: Magnitude of flow rate (mm3/s) from flowfield reconstruction of 2. Format: 3D-array of double, x=1:65, y=1:65, z=1:61.
  5. BA6_mag_1_01.raw.corrected.view.raw: µCT of the inlet section before leaching as normalized graylevel data, voxel size = 10.032 µm. Format: 3D-array of UInt16, x=1:2446, y=1:2450, z=1:1852. 
  6. BA6_mag_1_after_10u_01_to_befor.diff.view.raw: difference image of matched graylevels after-before leaching, voxel size = 10.032 µm. Format: 3D-array of (signed) Int16, x=1:2446, y=1:2450, z=1:1852. 

Keywords: positron emission tomography; computed tomography; microCT; reactive transport; secondary porosity; formation damage; sandstone diagenesis; leaching

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Permalink: https://www.hzdr.de/publications/Publ-41206


Highly Open Phosphorized PtNi Nanohexapod/N-doped Graphene Aerogel for High-Performance Alkaline Hydrogen Evolution

Yang, J.; Wang, J.; Hübner, R.; Tao, X.; Ren, Y.; Zheng, Z.; Liu, W.

Abstract

Developing cost-effective, high-efficiency, and stable electrocatalysts for the hydrogen evolution reaction (HER) in alkaline electrolytes is of critical importance for realizing renewable hydrogen technologies. However, the sluggish HER kinetics and unsatisfied stability remain critical challenges for their practical applications. Herein, a hierarchically porous phosphorized Pt-Ni nanohexapod/N-doped graphene aerogel (P-PtNiNH/NGA) constructed by an oxidation-phosphorization-controlled reconfiguration strategy is presented. It enables fast water dissociation kinetics for an abundant supply of hydrogen ions, strong electron interaction for optimal intermediate adsorption, and an excellent anchoring effect of the NGA to avoid the aggregation and Ostwald ripening of the PtNiNHs, thus exhibiting superior activity and exceptional stability toward alkaline HER. The P-Pt1Ni2NH/NGA exhibits an ultralow overpotential of 15 mV at a current density of 10 mA cm-2, a low Tafel slope of 37 mV dec-1, and long-term stability, which are superior to commercial Pt/C. Moreover, the P-Pt1Ni2NH/NGA shows a high mass activity of 13.4 mA μg-1 and a large TOF value of 13.5 s-1 at an overpotential of 100 mV, which are 8.8 times and 9.0 times higher than commercial Pt/C (under the same Pt loading of ≈9.1 μg cm-2). This work is of high inspiration for catalyst design to obtain ideal alkaline HER performance.

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Permalink: https://www.hzdr.de/publications/Publ-41205


Erstellung einer wiederverwendbaren Messinfrastruktur an der HAMSTER-Forschungsanlage

Gorgis, J.

Abstract

Die moderne Forschungslandschaft stellt hohe Anforderungen an Messsysteme – sie müssen präzise, flexibel und weitgehend automatisiert arbeiten, um komplexe Versuchsreihen effizient zu unterstützen. In der Forschungsanlage HAMSTER (Helmholtz Accelerator Mass Spectrometer Tracing Environmental Radionuclides) wird das etablierte EPICS-Kontrollsystem als einheitliche Schnittstelle zur Hardware eingesetzt, was eine verlässliche Basis für die Umsetzung höherer Automatisierungsmaßnahmen bildet.
Das Projekt ROCK-IT (Remote, Operando Controlled, Knowledge-driven, and IT-based) soll eine Softwarelösung schaffen, die den Messbetrieb einer Anlage mit einem hohen Automatisierungsgrad ermöglicht. Neben der Integration moderner Technologien wie Containerisierung, bestehenden Anwendungen und Services aus dem Bluesky-Ökosystem sowie Continuous Integration Pipelines wurde auch eine benutzerfreundliche Web-Oberfläche realisiert, um die Bedienprozesse zu vereinfachen. Durch die systematische Verknüpfung von Hardware, Software und IT-Methoden soll das System zudem flexibel an zukünftige Anforderungen angepasst werden.

Keywords: HAMSTER; ROCK-IT; Bluesky; EPICS

Involved research facilities

  • HAMSTER
  • Lecture (Conference)
    SEI-Tagung 2025, 24.-26.03.2025, Dresden, Deutschland

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Permalink: https://www.hzdr.de/publications/Publ-41193


Data publication: Citric and malic acids influence uranium(VI) uptake into Brassica napus in hydroponic culture by affecting solubility and speciation

John, W. A.; Steudtner, R.; Jessat, J.; Hübner, R.; Bok, F.; Sachs, S.

Abstract

The stored data sets represent the analytical, spectroscopic, and microscopic data that were used for the publication about the influence of citric and malic acids on the uranium(VI) uptake into Brassica napus plants in hydroponic culture by affecting solubility and speciation of uranium(VI).

Keywords: Uranium; Plants; Bioavailability; Citric acid; Malic acid; Solubility

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Permalink: https://www.hzdr.de/publications/Publ-41186


Magnetization process of a quasi-two-dimensional quantum magnet: Two-step symmetry restoration and dimensional reduction

Reinold, A.; Berger, L.; Raczkowski, M.; Zhao, Z.; Kohama, Y.; Gen, M.; Gorbunov, D.; Skourski, Y.; Zherlitsyn, S.; Assaad, F. F.

Abstract

We report on a comprehensive thermodynamic study of a quasi-two-dimensional (quasi-2D) quantum magnet Cu2(OH)3Br which in the 2D layer can be viewed as strongly coupled alternating antiferromagnetic and ferromagnetic chains. In an applied magnetic field transverse to the ordered spins below TN = 9.3 K, a field-induced phase transition from the 3D ordered to a disordered phase occurs at Bc = 16.3 T for the lowest temperature, which is featured by an onset of a one-half plateaulike magnetization. By performing quantum Monte Carlo simulations of the relevant 2D model, we find that the plateaulike magnetization corresponds to a partial symmetry restoration and the full polarization in the ferromagnetic chains. Our numerical simulations also show that the magnetization saturation occurs with full symmetry restoration at a much higher field of Bs ≃ 95 T, corresponding to a 1D quantum phase transition in the antiferromagnetic chains. We argue that the experimentally observed field-induced phase transition at Bc follows from the partial symmetry restoration and the concomitant dimensional reduction.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

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Permalink: https://www.hzdr.de/publications/Publ-41184


Magnetism in the Jeff = 1/2 kagome antiferromagnet Nd3BWO9: Thermodynamics, nuclear magnetic resonance, muon spin resonance, and inelastic neutron scattering studies

Yadav, A.; Elghandour, A.; Arh, T.; Adroja, D. T.; Le, M. D.; Stenning, G. B. G.; Aouane, M.; Luther, S.; Hotz, F.; Hicken, T. J.; Luetkens, H.; Zorko, A.; Klingeler, R.; Khuntia, P.

Abstract

The intertwining of competing degrees of freedom, anisotropy, and frustration induced strong quantum fluctuations offers an ideal ground for realizing exotic quantum phenomena in the rare-earth based kagome lattice. Herein, we report the synthesis, structure, thermodynamic, muon spin relaxation (μSR), nuclear magnetic resonance (NMR), and inelastic neutron scattering (INS) studies of a frustrated quantum magnet Nd3BWO9 (NBWO), wherein Nd3+ ions constitute a distorted kagome lattice. The INS experiments on NBWO allow us to establish a detailed crystal electric field (CEF) spectrum. The magnetic susceptibility reveals the presence of two energy scales in agreement with the INS results, wherein the higher-energy state is dominated by the thermal population of CEF excitations. The lowest Kramers ground-state doublet is well separated from the excited state, suggesting that the compound realizes a low-energy Jeff = 1/2 state at low temperatures. The low-energy state is witnessed via thermodynamic results that reveal an anomaly at 0.3 K typical of a phase transition, which is attributed to the presence of complex magnetic ordering phenomena. The broad maximum in the specific heat well above 0.3 K indicates the presence of short-range spin correlations. The isothermal magnetization reveals a field-induced 1/3 magnetization plateau at low temperatures. μSR relaxation rate experiments, on the other hand, neither show the signature of a phase transition nor spin freezing down to 34 mK. The zero-field μSR relaxation rate is governed by an Orbach process and reveals the presence of fluctuating moments owing to the depopulation of crystal field levels, reflected as a constant value of the relaxation rate in the temperature range 0.04 ⩽ T ⩽10 K. NMR results indicate the presence of fluctuating Nd3+ moments down to 1.8 K, consistent with μSR experiments. Our comprehensive results reveal that a field-induced quantum phenomenon is at play, exemplifying the proximity effect of competing magnetic states and the coexistence of static and fluctuating moments along with short-range spin correlations in this frustrated kagome magnet. The broad rare-earth RE3BWO9 family of frustrated kagome magnets is a promising candidate for hosting exotic quantum states driven by spin-orbit coupling and frustration.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-41183


Role of point defects on the superconducting transition temperature in NbTIN thin films with positron annihilation spectroscopy

Klug, S.; Lakki Reddy Venkata, B. R.; Zubtsovskii, A.; Butterling, M.; Liedke, M. O.; Hirschmann, E.; Wagner, A.; Jiang, X.

Abstract

Positron annihilation spectroscopy (PAS) is a non-destructive method for studying point defects in materials with high sensitivity. It can sense defect densities in the range of 10^15 to 10^19 cm^−3. The time for positrons to annihilate with electrons depends on the local electron density. Therefore, positrons can be trapped in neutral and negatively charged open-volume defects. Positrons are implanted into the studied material with a defined implantation energy. Changing of this energy allows for depth-resolved characterization. The user facility ELBE of HZDR provides the two main PAS techniques Doppler broadening spectroscopy (DBS) and positron annihilation lifetime spectroscopy (PALS) which allows for evaluation of the atomic environment of defects as well as defect size and density. In this contribution the most recent results of magnetron sputtered NbTiN thin films as promising candidate for improving the characteristics of superconducting radio-frequency cavities (SRF cavities) will be discussed. The correlation between defect size and their concentration and the superconducting transition temperature will be highlighted.

Keywords: Superconductivity; Magnetron sputtering; Thin films; Positron annihilation spectroscopy; Point defects

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Related publications

  • Lecture (Conference)
    DPG Spring Meetings 2025, 16.-21.03.2025, Regensburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-41182


Netto-Null-2050 Reality-Check Report

Köhnke, F.; Rhoden, I.; Prats Salvado, E.; Pregger, T.; Kronshage, S.; König, R.; Fogel, S.; Klassen, T.; Sachs, T.; Schätzler, K.; Jacob, D.; El Zohbi, J.; Brinkmann, T.; Dittmeyer, R.; Hampel, U.; Mayer, M.; Monnerie, N.; Rau, B.; Schill, E.; Steuri, B.

Abstract

Die globale Forderung nach CO2-Neutralität, wie sie im Pariser Klimaabkommen
(UNFCCC, 2015) und in Folgearbeiten wie dem Sechsten Sachstandsbericht des
Intergovernmental Panel on Climate Change (IPCC, 2021) formuliert wurde,
unterstreicht die Notwendigkeit von Strategien zur Adressierung von fossilen
Restemissionen, die nicht oder nur mit sehr hohen Kosten vermeidbar sind. Vor
diesem Hintergrund wurde das interdisziplinäre Projekt Netto-Null-2050 ins Leben
gerufen, das Wissenschaftler:innen aus acht Helmholtz-Forschungszentren
zusammenbringt. Ziel des Projekts war es, die umfangreiche wissenschaftliche
Expertise der Helmholtz-Zentren zu bündeln, um Optionen zur CO2-Vermeidung und
-Entnahme umfassend zu bewerten und Lösungsansätze zur Erreichung der
Klimaneutralität in Deutschland zu entwickeln.
In der ersten Projektphase entstand mit dem Netto-Null-2050 Wegweiser (Jacob et
al., 2023) ein Katalog wissenschaftlich fundierter Handlungsempfehlungen, der
Strategien für den Übergang Deutschlands zur CO2-Neutralität bis zur Mitte des
Jahrhunderts aufzeigt. Dabei wurde betont, dass der Zeitraum bis 2030
entscheidend ist: Ansätze zur Kohlenstoffentnahme müssen intensiv erforscht und
erprobt sowie die notwendigen politischen und rechtlichen Rahmenbedingungen
geschaffen werden.
Dieser in der zweiten Projektphase erstellte Bericht zum Reality-Check baut auf
diesen Empfehlungen auf und dient der Validierung und Weiterentwicklung der
vorgeschlagenen Maßnahmen. Die Überprüfung erfolgte in einem dreistufigen
Prozess: (1) Identifikation relevanter Akteur:innen wie z. B. Praxisexpert:innen aus
der Industrie für ausgewählte Maßnahmen, (2) Sammlung ihrer Positionen durch
Interviews beziehungsweise die Analyse öffentlicher Stellungnahmen und (3)
Synthese und Interpretation des Feedbacks. Für die Diskussion von Empfehlungen
zum Energiesystem wurden auch aktuelle Bewertungen und Positionierungen von
relevanten Wissenschaftler:innen herangezogen und Transformationspfade in
Szenarien mit der realen Entwicklung verglichen. Die Fragen, wie Machbarkeit und
Zielerreichung bewertet werden und welche Implikationen aus den Aussagen und
Positionierungen für die Umsetzung der Netto-Null-2050-Empfehlungen gezogen
werden können, stehen im Mittelpunkt des Reality-Checks.
Obwohl der Reality-Check aufgrund der begrenzten Anzahl an Maßnahmen und
Einbeziehung von Akteur:innen nicht alle Aspekte abdecken konnte, stellt er einen
wichtigen ersten Schritt dar, um die Handlungsempfehlungen iterativ zu bewerten
und an die praktischen Herausforderungen anzupassen.
Darüber hinaus hat der Reality-Check versucht, Verbindungen zwischen
Akteur:innen zu fördern, die traditionell nicht gut miteinander verbunden waren,
deren Zusammenarbeit aber immer wichtiger geworden ist. So wurde beispielsweise
das kritische Dreieck zwischen Forschungseinrichtungen, der etablierten Industrie
und aufstrebenden Start-ups hervorgehoben, deren Vernetzung den
Technologietransfer erleichtert.
Der vorliegende Bericht stellt die Ergebnisse dieses Prozesses vor, indem er das
Feedback von Interessengruppen außerhalb der unmittelbaren wissenschaftlichen
Gemeinschaft zusammenfasst und dessen Auswirkungen auf die ursprünglichen
Empfehlungen analysiert. Durch die Integration dieser verschiedenen Perspektiven
wird versucht, die Praktikabilität und Effektivität der vorgeschlagenen Maßnahmen
zu verbessern und so zu dem gemeinsamen Ziel beizutragen, eine CO2-neutrale
Zukunft zu erreichen.

Involved research facilities

  • TOPFLOW Facility
  • Other report
    Hamburg: Eigenverlag, 2025
    63 Seiten

Permalink: https://www.hzdr.de/publications/Publ-41179


Dataset for "Time-resolved nanospectroscopy of III–V semiconductor nanowires"

Luferau, A.; Pashkin, O.; Winnerl, S.; Obst, M.; Kehr, S. C.; Dimakis, E.; de Oliveira, T.; Eng, L. M.; Helm, M.

Abstract

Raw data, processed data in Origin files and Python scripts for modeling and fitting

Downloads

Permalink: https://www.hzdr.de/publications/Publ-41177


mTeSS-X Deliverable D1: Requirements analysis based on the two TeSS instances from ELIXIR and PaNOSC

Reed, P.; Bacall, F.; Andrabi, M.; Goble, C.; Knodel, O.; Voigt, M.; Rioja, K.

Abstract

This document describes the mTeSS-X project requirements analysis, following the first two meetings of the focus group. In these meetings, the use cases of two TeSS instances from ELIXIR and PaNOSC were considered, with further input from project supporters. The user personas, user stories and requirements are described, followed by the metadata schema development plan.

Keywords: TeSS; mTeSS-X; OSCARS; PaN-Training; education; training catalogue; PANOSC; ELIXIR; EOSC

Permalink: https://www.hzdr.de/publications/Publ-41176


Gamma-ray strength functions at low energy

Schwengner, R.

Abstract

The excitation and deexcitation of the nucleus by electromagnetic radiation at high excitation energy and high level density are described by means of γ-ray strength functions (γSF) which represent average transition strengths in a certain energy range. The experimental determination and the
theoretical understanding of the properties of γSF has attracted increasing interest because of their importance for the accurate description of photonuclear reactions and the inverse radiative-capture reactions, which play a central role in in the synthesis of the elements in various stellar environments. The standard electric dipole (E1) strength functions used in statistical reaction-model calculations are Lorentz functions adjusted to (g,n) reaction data that represent the isovector giant dipole resonance (GDR). To test the low-energy region of γSF below the neutron-separation energy, experiments using photon scattering or light-ion induced reactions are performed, in which nuclear levels below the particle-separation energies are excited. Photon-scattering experiments using broad-band bremsstrahlung at theγELBE facility of the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) as well as using quasi-monoenergetic, polarized photon beams produced at the High-Intensity γ-Ray Source (HIγS), of the Triangle Universities
Nuclear Laboratory (TUNL) in Durham, NC, reveal extra E1 strength on top of the tail of a Lorentz function considered as a pygmy dipole resonance (PDR). The analysis including the quasicontinuum in the γ-ray spectra and results are presented. Recently, a strong upbend of the γSF toward zero transition energy has been observed in light-ion induced reactions. This low-energy upbend can be described on the basis of large-scale shell-model
calculations as caused by a large number of magnetic dipole (M1) transitions linking excited states with configurations dominated by protons and neutrons in high-j orbitals. A study of a series of isotopes from shell closures to open shells is presented that shows a correlation between the low-energy upbend and the scissors mode, a fundamental M1 excitation occurring in deformed nuclei.

Keywords: Nuclear structure; Photon scattering; Electromagnetic transitions; gamma-ray strength functions; Cross sections; shell-model calculations

Involved research facilities

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  • Invited lecture (Conferences)
    Institutsseminar des IKTP der TU Dresden, 23.01.2025, Dresden, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-41174


SRF Gun Cavity Development Progress Report

Hallilingaiah, G.

Abstract

Reported the current status of the SRF gun cavity design.

Involved research facilities

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  • Lecture (Conference)
    SRF Gun Cluster Meeting, 18.03.2025, PITZ, Berlin, Germany

Permalink: https://www.hzdr.de/publications/Publ-41171


Development of Degradable Electrodes for Transient Electrochemical Biosensors

Janićijević, Ž.

Abstract

This is a pitch talk about the opportunity to develop degradable electrodes for transient electrochemical sensors based on the composite of polycaprolactone and molybdenum. There is no official abstract.

  • Lecture (others)
    Clinicum Digitale 2025, 24.03.-02.04.2025, Dresden, Germany

Permalink: https://www.hzdr.de/publications/Publ-41168


Effective time-dependent temperature for fermionic master equations beyond the Markov and the secular approximations

Litzba, L.; Kleinherbers, E.; König, J.; Schützhold, R.; Szpak, N.

Abstract

We consider a fermionic quantum system exchanging particles with an environment at a fixed temperature and study its reduced evolution by means of a Redfield-I equation with time-dependent (non-Markovian) coefficients. We find that the description can be efficiently reduced to a standard-form Redfield-II equation, however, with a time-dependent effective bath temperature obeying a universal law. At early times, after the system and environment start in a product state, the effective temperature appears to be very high, yet eventually it settles down towards the true environment value. In this way, we obtain a time-local master equation, offering high accuracy at all times and preserving the crucial properties of the density matrix. It includes non-Markovian relaxation processes beyond the secular approximation and time-averaging methods and can be further applied to various types of Gorini-Kossakowski-Sudarshan-Lindblad equations.We derive the theory from first principles and discuss its application using a simple example of a single quantum dot.

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Permalink: https://www.hzdr.de/publications/Publ-41167


Immobilization of Chromium by Iron Oxides in Nickel–Cobalt Laterite Mine Tailings

Esther Delina, R.; Perez, J. P. H.; Roddatis, V. V.; Stammeier, J. A.; Prieur, D.; Scheinost, A. C.; Tan, M. M.; Garcia, J. J. L.; Arcilla, C. A.; Benning, L. G.

Abstract

Mine tailings generated from hydrometallurgicalprocessing of nickel−cobalt laterite deposits contain high levels ofchromium (Cr), with the hexavalent species being a toxic pollutantand carcinogen. However, the partitioning, speciation, and localbonding environment of Cr in the mine tailings remain largelyunknown, hindering our ability to predict its toxicity and long-termbehavior. Coupling detailed mineralogical, spectroscopic, andgeochemical characterization with sequential extraction of tailingsfrom active and rehabilitated dams, we show that Cr is present in itsleast toxic form, Cr(III), and largely immobilized by recalcitrantminerals. This immobilization also regulates dissolved Crconcentrations in the interacting waters to levels up to five timeslower than the global regulatory limit (50 μg L−1). Solid-phase Crconcentrations were ≤1.5 wt % with 39−61% of Cr incorporated into hematite, and to a lesser extent, alunite, both of which formedearly in the hydrometallurgical extraction process of mined laterite ores. The remaining Cr was present as recalcitrant chromiteresidues from the primary source laterites. We highlight that, although hydrometallurgical extractions liberate Cr from laterite oresduring processing, they also provide ideal chemical pathways for the formation of highly stable, crystalline hematite that successfullysequesters Cr, while restricting its environmental mobility.

Keywords: mine waste; high pressure acid leaching; coprecipitation; hematite; chromite; sequential extraction

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Permalink: https://www.hzdr.de/publications/Publ-41166


Symmetrische Motoranschlussleitungen Betrachtung zum Störverhalten und zur elektrischen Sicherheit von Kabeln mit gedrittelten Schutzleitern

Sorge, W.

Abstract

Symmetrische Motoranschlussleitungen
--- Betrachtung zu Störeinkopplungen und zur elektrischen Sicherheit von Anschlusskabeln mit Drillingsschutzleitern ---

Elektromotoren werden häufig über ihre Versorgungsströme gesteuert.
Das Steuern der Motorströme und damit der zugeführten Leistung verändert deren mechanisches Verhalten.
Jedoch werden diurch das Verändern der Motorströme auch Störströme erzeugt, die sich nicht vollständig vermeiden lassen.

Um die Störwirkung zu mindern, werden Anschlusskabel so gestaltet, dass Störströme weniger auf angeschlossene Systeme einwirken:

Hersteller bieten Motoranschlusskabel an, bei denen eine dreigeteilte Anordnung der Schutzleiter die Symmetrie der Kabel verbessern.
Im Vortrag werden Erkenntnisse über die Feldverteilung in diesen Kabeln vorgestellt, verursacht durch Nutz- wie auch durch Störströme.
Hieraus werden mögliche Wirkungen abgeleitet.

Im Vortrag wird auch der Einfluss der Teilung des Schutzleiters auf die elektrische Sicherheit betrachtet.
Angaben der Anbieter hierzu werden untersucht.

Keywords: elektrische Sicherheit; elektromagnetische Störfestigkeit; Übertragung von Elektroenergie

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  • Open Access Logo Lecture (Conference)
    SEI Tagung, 24.-26.03.2025, Dresden-Rossendorf, Deutschland

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Permalink: https://www.hzdr.de/publications/Publ-41165


Enhanced Mixing in Microflow Systems Using Magnetic Fields - Experimental and Numerical Analyses

Wojnicki, M.; Yang, X.; Zabinski, P.; Mutschke, G.

Abstract

This study presents both numerical and experimental analyses of enhanced mixing
in a microflow system under the influence of a magnetic field. The research employed
COMSOL Multiphysics for numerical simulations and Particle Image Velocimetry (PIV) for
experimental validation. In the experimental microfluidic setup, permanent neodymium
magnets were used to influence a laminar flow of water partially enriched with Ho(III)
ions using the magnetic field. The findings confirmed that the strong interaction between
Ho(III) ions and the magnetic field significantly affected the flow and may have resulted in
vortex shedding downstream of the region with the highest magnetic field intensity. The
numerical simulations demonstrated good agreement with the PIV experimental results.
These findings suggest that it is possible to significantly enhance mixing in microflow systems
without mechanical components, solely by exploiting the differences in the magnetic
properties between the mixing substances. Traditionally, microreactors have been limited
by mixing speeds governed by diffusion. These new results indicate the practical possibility
of increasing mixing intensity in a cost-effective and safe manner.

Keywords: microflow systems; mixing; magnetic field; magnetic gradient force

Permalink: https://www.hzdr.de/publications/Publ-41164


Improved lattice elongation for Fe8Nx (x > 1) thin films prepared via nitrogen ion implantation

d’Andrea, G.; Zhou, S.; Kentsch, U.; Major, M.; Rani, P.; Gkouzia, G.; Zhao, B.; Ablets, Y.; Dirba, I.; Zhang, H.; Alff, L.

Abstract

Iron nitrides α″-Fe16N2 and α′-Fe8N have attracted significant interest due to their potential as a rare-earth-free semi-hard magnetic materials. In this work, a systematic investigation of nitrogen ion implantation fluences on iron thin films was performed to increase tetragonality beyond what is currently possible, thereby enhancing the magnetic performance. A structural characterization of samples with a different nitrogen concentration highlighted that α′-Fe8N can be formed within a fluence range from 4 to 7 × 1016 N+ ions cm−2. For increasing doses, at first crystalline Fe8Nx (x > 1) was obtained; afterward, the material went through amorphization. After annealing samples at 150 °C, the elongation of their lattice constant reached values higher than that of stoichiometric Fe8Nx (x = 1), with a largest value of 3.158(3) Å at 11.6(1) N at. % versus 3.1455 Å at 11.1 N at. %. Characterization of the magnetic properties revealed that samples with the highest magnetization also exhibit an increase in magnetic hardness.

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Permalink: https://www.hzdr.de/publications/Publ-41160


Giant berry curvature in amorphous ferromagnet Co2MnGa

Zhao, W.; Zhang, Y.; Yin, Y.; Xing, K.; Zhou, S.; Bake, A.; Akhgar, G.; Cortie, D.; Chen, L.; Wang, X.; Rule, K. C.; Medkehar, N. V.; Granville, S.; Karel, J.

Abstract

In amorphous materials, long-range translational order breaks down, and k is no longer a good quantum number; however, some of the phenomena, for instance ferromagnetic interactions and a mechanism similar to the Berry curvature, can be preserved. Here, we demonstrate a giant Berry-curvature-induced anomalous Hall effect and anomalous Hall angle in amorphous Co2MnGa (a-CMG) thin films. Remarkably, the effect presents the same magnitude as high-quality crystalline CMG with the L21 structure. The elastic neutron scattering peak in a-CMG is centered close to the crystalline phase, indicating that the amorphous material presents similar local atomic environments and magnetic interactions. First-principles density functional theory calculations further show that the anomalous Hall conductivity arises only when the local environments in the amorphous structure are similar to the L21 phase. Our work strongly points to the application of low-cost, industry-compatible, and thermally stable amorphous topological materials in emerging electronic and spintronic applications.

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  • Secondary publication expected from 10.02.2026

Permalink: https://www.hzdr.de/publications/Publ-41150


Association between dose to cardiac structures and overall survival: A multivariable analysis in a large, multi-institutional database of stage III NSCLC patients with external validation

Garrett Fernandes, M.; Bussink, J.; Wijsman, R.; Gouw, Z.; Weiß, A.; Sijtsema, N. M.; Canters, R.; Hope, A.; de Ruysscher, D.; Troost, E. G. C.; Sonke, J.-J.; Stam, B.; Monshouwer, R.

Abstract

Background and Purpose: Inconsistencies in identifying dose-limiting cardiovascular substructures for treating stage III non-small cell lung cancer (NSCLC) have hindered the implementation of cardiac sparing treatment planning guidelines. This study aims to address these inconsistencies by performing a multivariable survival analysis with overall survival as the endpoint using a large, multinational database, followed by external validation.
Materials and Methods: Clinical and dosimetric parameters from 1587 stage III NSCLC patients treated at five institutes were analyzed. The whole heart, four cardiac chambers, great vessels and their combinations were considered. The dataset was divided into a training set (four institutes) and a test set (one institute). The optimal parameter set was identified through cross-validation, and the resulting multivariable Cox regression model was externally validated using the test set. Adjusted hazard ratios (aHRs) for all cardiovascular parameters were evaluated.
Results: The strongest associations were found for low Dx% parameters. However, their incremental contribution to model performance, compared to clinical and lung dosimetric parameters only, was low, with small effect sizes. Specifically, the cardiovascular parameter identified by parameter selection was Left Side D5% (aHR: 1.007 Gy−1, 95 % CI: 1.004 – 1.010 Gy−1, p < 0.0001), which provided a slight improvement in model concordance index of 0.0062 (95 % CI: 0.0000–0.0127) in the training set and 0.0037 (95 % CI: −0.0200–0.0280) in the test set.
Conclusions: Although significant associations between cardiovascular parameters and survival were found, their small effect sizes should be considered when prioritizing cardiac sparing in stage III NSCLC treatment.

Keywords: Non-Small-Cell Lung Carcinoma; Radiotherapy; Cardiotoxicity; Survival; Survival Analysis

Permalink: https://www.hzdr.de/publications/Publ-41149


Versatile Green Transfer of Magnetoelectronics with Loss-free Performance and High Adhesion for Interactive Electronics

Bezsmertna, O.; Xu, R.; Oliveros Mata, E. S.; Avdoshenko, S.; Voigt, C.; Mosch, S.; Vinnichenko, M.; Makarov, D.

Abstract

A stringent quality requirement for a nm-thick multi-stack heterostructures and delicate antiferromagnetic interlayer couplings inherent to giant magnetoresistive (GMR) sensors limits their seamless integration on objects with non-planar surfaces and/or biological structures. Here, we demonstrate a green transfer method of high performance and mechanically robust GMR sensors to a wide range of biological, organic and inorganic substrates. Importantly, our transfer technique relies on water and biocompatible polyvinyl alcohol (PVA) polymer and requires no complex treatments that involve harsh chemicals and conditions, allowing for transferring sensors causing no harm to the environment. A high surface tension of water employed in our transfer process ensures a smooth spreading of the sensor film reinforced by the hydrophilic PVA layer, mitigating stress concentrations in the GMR film and preserving its structural integrity. Transferred sensors maintain their performance, low noise and reveal excellent mechanical stability even after 3000 bending cycles. This green transfer technique of GMR sensors fosters various applications, e.g., to function as a human-machine interface in wearable and interactive electronics.

Keywords: magnetoelectronics; transfer printing; sustainable electronics; flexible electronics; human- machine interface

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Permalink: https://www.hzdr.de/publications/Publ-41148


Experimental and numerical investigation of the hydrodynamics in a three-phase bubble column

Sommer, A.-E.; Draw, M.; Eckert, K.; Rzehak, R.

Abstract

Three-phase bubble columns are widely used in process engineering. E.g. in froth flotation they serve the separation of valuable mineral particles from worthless gangue material. The counter-current flow of particles and bubbles provides good mixing in combination with low energy consumption and costs. Still, the complex gas-solid-liquid flow is not very well understood. Therefore, the present study experimentally investigates the hydrodynamics in a three-phase bubble column to improve the understanding of the effects of the solid particles on the bubble-driven flow and to provide a high-quality database for comparison with computational fluid dynamics simulations. This extends a previous study of two-phase flows in the same system.

In the experiments, air bubbles are injected by needles, while for the solid phase, nearly neutrally buoyant PMMA particles are suspended in deionized water. To allow simultaneous measurements of bubble size, disperse phase fractions, and velocity field of all three phases, a combined system of planar shadow imaging and PIV is applied. The conducted experiments cover a range of measurement positions, gas volume fluxes, bubble diameters and solid concentrations. The time-averaged liquid velocity field is obtained and critically discussed for these measurement configurations. Subsequently, the locally resolved liquid velocity is combined with the simultaneously measured dispersed phase fraction and velocity, to provide a complete description of the hydrodynamics.

The simulations are performed using the Eulerian framework in which only phenomena occurring on large scales comparable to the column size are revolved, while small-scale phenomena on the scale of individual bubbles or particles are modeled instead. A combination of previously applied models for gas-liquid and solid-liquid two-phase flows is tested in the present work. These models comprise bubble and particle forces, in particular drag, virtual mass, (shear-) lift, wall (-lift) and turbulent dispersion forces, as well as bubble- and particle-induced turbulence. A reasonable agreement is obtained between these simulations and the experimental data for three-phase flows.

Keywords: bubble-column; three-phase flow; PIV; shadowgraphy; Euler-Euler simulation

  • Poster
    Jahrestreffen der DECHEMA/VDI-Fachgruppen Mischvorgänge, Hochdruckverfahrenstechnik und Mehrphasenstörmungen, 19.-21.03.2025, Hamburg, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-41144


A contribution to the multidimensional characterisation and separation of ultrafine particles (Dissertation data)

Sygusch, J.

Abstract

The repository contains data of the dissertation:

Title: A contribution to the multidimensional characterisation and separation of ultrafine particles

Author: M.Sc. Johanna Sygusch

Faculty: Faculty of Mechanical, Process and Energy Engineering of the Technische Universität Bergakademie Freiberg

Year: 2025

It contains Excel sheets with the summarized data, as well as two zip files containing the flow cytometry measurements and the MLA images.

Keywords: Flotation; Wettability; Ultrafine particles; Multidimensional; Separation; Fine particle characterisation

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Permalink: https://www.hzdr.de/publications/Publ-41143


Sensitivity Analysis Comparisons on Geologic Case Studies: An International Collaboration, Volume 2

Swiler, L. P.; Becker, D.-A.; Brooks, D.; Koskinen, L.; Kupiainen, P.; Plischke, E.; Röhlig, K.-J.; Samper, J.; Spiessl, S. M.

Abstract

Over the past six years, an informal working group has developed to investigate existing sensitivity analysis methods, examine new methods, and identify best practices. The focus is on the use of sensitivity analysis in case studies involving geologic disposal of spent nuclear fuel or nuclear waste. To examine ideas and have applicable test cases for comparison purposes, we have developed multiple case studies. Four of these case studies were presented in a first Volume, Volume 1 titled “Sensitivity Analysis Comparisons on Geologic Case Studies: An International Collaboration”, SAND2021-11053. Three additional case studies are presented in this report: the GRS LILW (low and intermediate level waste) case in a salt repository, the SNL generic crystalline case, and the UDC reactive transport case. The three case studies discussed and analyzed in Volume 2 are more complicated than those in Volume 1, due to more nonlinear behavior, outputs which exhibit bifurcation, regime changes, and nested sampling. We present the different sensitivity analysis methods investigated by various groups, the results obtained by different groups and different implementations, and summarize our findings.

  • Other report
    Albuquerque, New Mexico: Sandia National Laboratories, 2025

Permalink: https://www.hzdr.de/publications/Publ-41142


Global sensitivity analyses for test planning with black-box models for Mars Sample Return

Cataldo, G.; Borgonovo, E.; Siddens, A.; Carpenter, K.; Nado, M.; Plischke, E.

Abstract

This work describes sensitivity analyses performed on complex black-box models used to support experimental test planning under limited resources in the context of the Mars Sample Return program, which aims at bringing to Earth rock, regolith, and atmospheric samples from Mars. We develop a systematic workflow that allows the analysts to simultaneously obtain quantitative insights on key drivers of uncertainty, the direction of impact, and the presence of interactions. We apply optimal transport-based global sensitivity measures to tackle the multivariate nature of the output and we rely on sensitivity measures that do not require independence between the model inputs for the univariate output case. On the modeling side, we apply multifidelity techniques that leverage low-fidelity models to speed up the calculations and make up for the limited amount of high-fidelity samples, while keeping the latter in the loop for accuracy guarantees. The sensitivity analysis reveals insights useful to understand the model's behavior and identify the factors to focus on during testing, in order to maximize the informational value extracted from these tests and ensure mission success even with limited resources.

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Permalink: https://www.hzdr.de/publications/Publ-41141


Direction of impact for explainable risk assessment modeling

Borgonovo, E.; Baucells, M.; de Rosa, A.; Plischke, E.; Barr, J.; Rabitz, H.

Abstract

Several graphical indicators have been recently introduced to help analysts visualize the marginal effects of inputs in complex models. The insights derived from such tools may help decision-makers and risk analysts in designing interventions. However, we know little about the adequacy and consistency of different indicators. This work investigates popular marginal effect indicators to understand whether they yield indications consistent with the properties of the quantitative model under inspection. Specifically, we examine the notions of monotonicity, Lipschitz, and concavity consistency. Surprisingly, only PD functions satisfy all these notions of consistency. However, when selecting the indicators, in addition to consistency, analysts need to consider the risk of model extrapolation. For situations where such risk is under control, we utilize individual conditional expectations together with PD plots. Two applications, on a NASA space risk assessment model and a susceptible exposed infected recovered (SEIR) model for the COVID-19 pandemic illustrate the insights obtained from these indicators.

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Permalink: https://www.hzdr.de/publications/Publ-41140


Global sensitivity analysis of integrated assessment models with multivariate outputs

Chiani, L.; Borgonovo, E.; Plischke, E.; Tavoni, M.

Abstract

Risk assessments of complex systems are often supported by quantitative models. The sophistication of these models and the presence of various uncertainties call for systematic robustness and sensitivity analyses. The multivariate nature of their response challenges the use of traditional approaches. We propose a structured methodology to perform uncertainty quantification and global sensitivity analysis for risk assessment models with multivariate outputs. At the core of the approach are novel sensitivity measures based on the theory of optimal transport. We apply the approach to the uncertainty quantification and global sensitivity analysis of emissions pathways estimated via an eminent open-source climate–economy model (RICE50+). The model has many correlated inputs and multivariate outputs. We use up-to-date input distributions and long-term projections of key demographic and socioeconomic drivers. The sensitivity of the model is explored under alternative policy architectures: a cost-benefit analysis with and without international cooperation and a cost-effective analysis consistent with the Paris Agreement objective of keeping temperature increase below 2°C. In the cost-benefit scenarios, the key drivers of uncertainty are the emission intensity of the economy and the emission reduction costs. In the Paris Agreement scenario, the main driver is the sensitivity of the climate system, followed by the projected carbon intensity. We present insights at the multivariate model output level and discuss how the importance of inputs changes across regions and over time.

Permalink: https://www.hzdr.de/publications/Publ-41139


In Situ X‑ray Diffraction Study of MXene Synthesis by the Reaction of Ti3AlC2 with Molten Zinc and Tin Chlorides

Iakunkov, A.; Boulanger, N.; Gurzeda, B.; Li, G.; Hennig, C.; Svitlyk, V.; Ry Vogel Jørgensen, M.; Kantor, I.; Baburin, I. A.; Max Hamedi, M.; Talyzin, A. V.

Abstract

Using molten salts for etching aluminum (Al) away from the MAX
phase for MXene synthesis is an attractive alternative method that allows one to
avoid the use of toxic hydrofluoric acid (HF) solutions. However, the mechanism
of the MAX phase reaction with molten salts remains to date unclear due to the
lack of in situ data. Here, we present a detailed in situ time-resolved synchrotron
radiation X-ray diffraction study of the MAX phase annealing in molten ZnCl2 and
SnCl2. The reaction of salts with the MAX phase is found to occur in two stages.
The initial period of annealing results in the delamination of two-dimensional
(2D) Ti3C2 layers, vigorous evolution of AlCl3 bubbles, and dissolution of Zn in a
ZnCl2 melt. The chlorine-terminated Ti3C2 sheets formed in the delaminated state
are restacked into a relatively well-ordered MXene structure (P63/mmc, a = 3.071 Å and c = 18.577 Å) during the prolonged
annealing in molten salts. Surprisingly, the data recorded directly in molten salts at temperatures up to 873 K demonstrate that
Ti3C2Clx MXene shows no swelling in both liquid ZnCl2 and SnCl2. The structure of MXene studied directly in the molten salts is
found to be the same as in ex situ experiments performed after cooling and water washing under ambient conditions. The absence of
the “pristine” melt-swollen phase indicates a rather different mechanism of MXene formation compared to HF-based solution
methods. Formation of MXene by gradually removing Al from the MAX phase starting at the edges of flakes and propagating into
the deeper parts of interlayers is not possible, since the molten salt is not capable of penetrating between Cl-terminated Ti3C2 layers.

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Permalink: https://www.hzdr.de/publications/Publ-41138


Advancing Carriers Mobility in MnSb2Te4 Thermoelectrics via Tailored Textures and Vacancy Modification

Xu, X.; Mao, D.; Liedke, M. O.; Butterling, M.; Cui, J.; Wang, J.; Luo, Y.; Ge, Z.; Hirschmann, E.; Wagner, A.; He, J.; Nielsch, K.; He, R.

Abstract

Enhancing carrier mobility plays a crucial role in significantly improving thermoelectric performance. However, due to the lack of a systematic strategy, achieving high mobility remains an elusive goal for most compounds. In this study, we applied the hot-forging method to polycrystalline MnSb₂Te₄, achieving a remarkable 300% improvement in carrier mobility. Through electron backscattering diffraction microstructural analysis, we demonstrated how optimizing textures can accelerate carrier movement in MnSb₂Te₄ bulk materials. Moreover, theoretical calculations, combined with experimental positron annihilation spectroscopy, revealed that Te vacancies help counteract intrinsic cation defects, leading to a simultaneous increase in carrier mobility. As a result, the hot-forged MnSb₂Te₄ specimen, with a diameter of 15 mm, reached a record-high maximum ZT value of 1.3 at 773 K and an impressive average ZT of 0.7 between 323 K and 773 K. The experimental output efficiency of 4.6%, observed at 773 K on our MnSb₂Te₄-based single-leg module, further confirms that the improved transport properties are due to the enhanced carrier mobility. This comprehensive study offers valuable insights into mobility enhancement in MnSb₂Te₄ and provides a promising direction for exploring similar improvements in other thermoelectric materials.

Keywords: thermoelectrics; electron mobility; positron annihilation spectroscopy; MnSb2Te; polycrystalline

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Permalink: https://www.hzdr.de/publications/Publ-41136


Influence of support pore size and porosity on epoxide-based TFC membranes

Lenaerts, N.; Verbeke, R.; Davenport, D. M.; Caspers, S.; Eyley, S.; Kantre, K.-A.; Volodine, A.; Helm, R.; Butterling, M.; Liedke, M. O.; Wagner, A.; Thielemans, W.; Meersschaut, J.; Dickmann, M.; Vankelecom, I. F. J.

Abstract

The drive to expand the implementation of membrane separation technology towards harsher environments prompted the development of chemically robust epoxide-based TFC membranes. This work seeks to better understand the influence of the support on epoxide-based TFC membrane performance and properties. More specifically, it investigates the impact of porous PAN support layers of different porosities and pore sizes on the formation of poly(epoxyether) (PEE) thin films via interfacial initiation of polymerization (IIP), and their more cross-linked and more charged PEE counterparts (XL-PEE) arising from a subsequent post-treatment step. A systematic study was conducted using a series of supports with pore sizes varying from 20 nm to 90 nm and porosities in the range of 4% to 10%, while maintaining identical synthesis conditions for the selective layer. The physicochemical properties of the selective layer were characterized in-depth with X-ray photoelectron spectroscopy (XPS), elastic recoil detection (ERD), transmission electron microscopy (TEM), positron annihilation lifetime spectroscopy (PALS), and atomic force microscopy (AFM) to elucidate the synthesis-structure-performance relationship. PEE TFC membranes comprising these supports had a broad range in water permeances of 5 – 30 L m−2 h−1 bar−1 with consistent methyl orange (327.33 g mol−1) rejections of ca. 90%. The densified XL-PEE TFC membranes all achieved ca. 65% NaCl rejections, again independent of the support properties. In contrast, more porous supports resulted in more permeable TFC membranes, which can be attributed to the so-called funnel effect. Additionally, the solvent used to prepare the support layers through non-solvent induced phase separation also impacted the selective layer by affecting the interfacial properties during IIP. This work thus demonstrates that the support can serve as an easy tool to fine-tune the performance of the next-generation of high-performance epoxide-based TFC membranes.

Keywords: nanofiltration; TFC membranes; Epoxide-based membranes; PAN support; Interfacial initiation of polymerization

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  • Secondary publication expected from 23.02.2026

Permalink: https://www.hzdr.de/publications/Publ-41135


Downscaling magnetic field gradients for structured copper magnetoelectrodeposition on the micrometer scale

Sgarbi Stabellini, F.; Singh, A.; Soldatov, I.; Schäfer, R.; Huang, M.; Mutschke, G.; Neu, V.; Gebert, A.; Leistner, K.

Abstract

Electrochemical deposition in magnetic field gradients is a promising method to synthesize structured deposits by exploiting the magnetic field gradient force. Typically, magnetic field gradient templates with dimensions in the millimeter range are used, but a downscaling is desirable from fundamental and application points of view. In the present study, pulse reverse plating of copper is performed in combination with four successively downscaled magnetic field gradient templates, which consist of three iron wires with diameters of 1 mm, 500 μm, 250 μm, and 125 μm. Structuring is demonstrated for all four templates, upon downscaling the Fe diameter within the templates. The deposited copper structures closely resemble the calculated profile of the magnetic field gradient term BgradB. The application of more negative deposition potentials leads to improved structuring. Based on the analysis of the current transients, this effect is explained by the action of the curl of the magnetic field gradient
force, which profits from the faster development of a steep Cu2+ concentration gradient due to the earlier transfer from a charge-transfer-controlled to a diffusion-limited deposition mode. Significant differences in morphology, ranging from needle-like growth to smooth deposits, are obtained, which vary with the magnetic field gradient profile and the deposition voltage. The results demonstrate that the combination of tailored magnetic field gradient templates and optimized electrochemical parameters offers an advanced route to control the shape and morphology of structured Cu deposits at the micrometer scale, with potential applications in microelectronics and catalysis.

Keywords: electrodeposition; magnetic field; magnetic forces; structured surfaces

Permalink: https://www.hzdr.de/publications/Publ-41131


Advances in Diclofenac Derivatives: Exploring Carborane-Substituted N-Methyl and Nitrile Analogs for Anti-Cancer Therapy

Selg, C.; Schuster, R.; Kazimir, A.; Lönnecke, P.; Wolniewicz, M.; Schädlich, J.; Laube, M.; Pietzsch, J.; Gordić, V.; Krajnović, T.; Mijatović, S.; Maksimović-Ivanić, D.; Hey-Hawkins, E.

Abstract

This study explores the anti-cancer potential of N-methylated open-ring derivatives of carborane-substituted diclofenac analogs. By N-methylation, the open-chain form could be trapped and cyclization back to lactam or amidine derivatives was inhibited. A small library of carborane- and phenyl-based secondary and tertiary arylamines bearing carboxylic acid or nitrile groups was synthesized and analyzed for their COX-affinity in vitro and in silico. The compounds were further evaluated against mouse adenocarcinoma (MC38), human colorectal carcinoma (HCT116) and human colorectal adenocarcinoma (HT29) cell lines and showed potent cytotoxicity. Additional biological assessments of the mode of action were performed using flow cytometric techniques and fluorescence microscopy. The data obtained revealed a common antiproliferative effect coupled with the induction of caspase-independent apoptosis and the specific effects of the compound on the phenotype of MC38 cells, resulting in impaired cell viability of MC38 cells and satisfactory selectivity exceeding the antitumor activity of diclofenac.

Permalink: https://www.hzdr.de/publications/Publ-41128


Stability of fluid layers carrying a normal electric current revisited

Priede, J.; Weber, N.
ContactPerson: Weber, Norbert

Abstract

In this report we revisit the basic model of electromagnetic interfacial instability originally due to Sneyd (1985). The model consists of horizontally unbounded fluid layers carrying a uniform normal current in the presence of a co-planar vertically invariant magnetic field. The absence of lateral boundaries in this model leaves the self-magnetic field determined up to a gradient of the scalar magnetic potential. This was deemed a major deficiency of the model in our first report. In particular, it was not obvious that the perturbation of magnetic field, which is postulated by Sneyd in terms of the electric potential perturbation satisfies not only Ampère’s law but also the continuity of tangential electric field across the interface. On the other hand, Sneyd’s solution is rather specific and limited by several assumptions typical for aluminium reduction cells and electric-arc furnaces. Therefore it may be worthwhile to revisit Sneyd’s model in a more general set-up and using alternative more transparent approach.

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Permalink: https://www.hzdr.de/publications/Publ-41127


Data publication: Short wavelength limit of the dynamic Matsubara local field correction

Dornheim, T.; Tolias, P.; Moldabekov, Z.; Vorberger, J.

Abstract

This repository contains all PIMC data presented in the publication "Short wavelength limit of the dynamic Matsubara local field correction", with the same units and conventions as in the figures.

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Permalink: https://www.hzdr.de/publications/Publ-41125


Electronic Supplementary Data of the Doctoral Thesis of Nils Reinhardt entitled "Mineral systems analysis of magmatic-hydrothermal skarn mineralization in the Schwarzenberg District, Germany"

Reinhardt, N.; Gutzmer, J.

Abstract

Electronic supplementary material related to the dissertation entitled “Mineral systems analysis of magmatic-hydrothermal skarn mineralization in the Schwarzenberg District, Germany” authored by Nils Reinhardt. The data contains the electronic supplementary material for chapters 3, 4, and 5, respectively, as noted in the respective file names.

Keywords: Schwarzenberg District; magmatic-hydrothermal skarn mineralization; Mineral systems

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Permalink: https://www.hzdr.de/publications/Publ-41124


Pion Boer–Mulders function using a contact interaction

Cheng, D.-D.; Cui, Z.-F.; Ding, M.; Roberts, C. D.; Schmidt, S. M.

Abstract

A symmetry preserving treatment of a vector ⊗ vector contact interaction (SCI) is used as the basis for calculations of the two pion transverse momentum dependent parton distribution functions (TMDs); namely, that for unpolarised valence degrees-of-freedom and the analogous Boer–Mulders (BM) function. Amongst other things, the analysis enables the following themes to be addressed: the quark current mass dependence of pion TMDs; the impact of the gauge link model on the positivity constraint that bounds the BM function relative to the unpolarised TMD; the equivalence of direct diagrammatic and light-front wave function TMD calculations; and the size of the BM shift. Interpreted astutely, these SCI results enable one to draw insightful pictures of pion TMDs.

Permalink: https://www.hzdr.de/publications/Publ-41123


Flow instability caused by temperature boundary conditions in a model of Czochralski crystal growth

Grants, I.; Pal, J.; Tsiapkinis, I.; Eckert, S.; Gerbeth, G.; Räbiger, D.; Dadzis, K.

Abstract

A weakly turbulent buoyancy-driven flow is studied experimentally and numerically in a liquid metal cylinder with small height-to-diameter
ratio. The cell represents a model of the Czochralski crystal growth process and includes heating at the bottom and non-uniform cooling at
the top. Transition to a non-axisymmetric roll-like flow structure (wind) is observed experimentally under conditions, which still produce a
nearly axisymmetric flow in the computations. It is shown that the contradiction can be explained by the flow sensitivity to temperature
boundary conditions at the cell bottom. It is made of a massive copper disk to approximate isothermal temperature conditions. Due to a finite
heat conductivity, the bottom is unable to sufficiently equalize the temperature over large distances. This deviation from isothermal conditions
is amplified in a separate experiment by a thin heat barrier at the cell’s bottom. In this case, the transition to wind is observed at a nearly
ten times lower heat flux both in numerics and experiment. The transition then produces a very long-period flow oscillation as the wind
erratically changes flow direction.

Keywords: flow instability; Czochralski process; crystal growth; Rayleigh–Benard

Permalink: https://www.hzdr.de/publications/Publ-41119


Growth history of garnet from the Dulong Sn-Zn-In polymetallic deposit: Geochemical and U–Pb age constraints and their metallogenic significance

Liu, S.; Ye, L.; Liu, Y.; Long, H.; Wei, C.; Xiang, Z.

Abstract

The Dulong skarn-type tin zinc indium (Sn-Zn-In) polymetallic deposit contains 5.5 million tonnes (Mt) Zn, 0.4 Mt. Sn, and 7 kt In. It is the third-largest cassiterite-sulfide deposit in China, and is located in the Laojunshan W–Sn polymetallic orefield on the southern margin of the Youjiang basin. While it is widely accepted that the Sn–Zn polymetallic mineralization is closely linked to the Yanshanian granites, the precise timing of skarn formation and its relationship to the granite magmatism has remained unclear due to a lack of reliable geochronological data. This has also hindered a comprehensive understanding of the ore-forming processes at Dulong. Garnet is a widely distributed major skarn mineral at Dulong. Field and laboratory studies have revealed two distinct garnet types (Grt I and II): Grt I is located near the main ore-controlling fault (FM), while Grt II is found near a shallow granite porphyry in eastern Dulong. Both types of garnet exhibit a core-mantle-rim structure, indicating that they were formed by multistage fluid metasomatism. In this study, in situ LA-ICP-MS U–Pb dating was carried out on both types of garnet. Additionally, major and trace element analyses of the garnet and its coexisting pyroxene were conducted to examine the formation and evolution of the skarn. The results show that Grt I has generally higher ΣREE, Y, HFSE, and U concentrations, suggesting that it was formed under low W/R ratios in a relatively reducing environment. The garnet contains a grossular core (Grt Ia), andradite mantle (Grt Ib), and a grossular-andradite solid solution rim (Grt Ic), reflecting an initial increase and then decrease in the W/R ratio of the magmatic-hydrothermal system. During this process, the fluid pH was neutral-acidic, and the oxygen fugacity (fO2) first decreased and then increased. In contrast, Grt II has lower ΣREE, Y, HFSE, and U concentrations, indicating its formation under higher W/R ratios in a more oxidizing environment. This garnet has also a grossular core (Grt IIa), andradite mantle (Grt IIb), and a grossular-andradite solid solution rim (Grt IIc). This reflects a system where the W/R ratio first increased and then decreased. The fluid pH shifted from neutral-acidic to acidic, and the fO2 increased gradually. LA-ICP-MS U–Pb dating yielded 93 ± 2.4 Ma to 90.9 ± 0.7 Ma for Grt I and 80.4 ± 6.6 Ma for Grt II. Comparing these results with published data on the Cretaceous regional magmatism and Sn-polymetallic mineralization, we conclude that the magmatichydrothermal activity that formed Grt I and Grt II was associated with the concealed phase-II and phase-III Laojunshan granite, respectively. This study highlights the opportunities offered by garnet U–Pb dating for elucidating the formation age and ore genesis of Sn–Zn skarn systems.

Keywords: U–Pb geochronology; Garnet chemistry; Pyroxene chemistry; Sn–Zn skarn; Dulong Sn–Zn polymetallic deposit

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  • Secondary publication expected from 01.04.2026

Permalink: https://www.hzdr.de/publications/Publ-41116


Anomalous current-electric field characteristics in transport through a nanoelectromechanical systems

Wu, C.; Ding, Y.; Yan, Y.; Su, Y.; Omollo Ayieta, E.; Radošević, S.; Engelhardt, G.; Schaller, G.; Luo, J.

Abstract

A deep understanding of the correlation between electronic and mechanical degrees of freedom is crucial to the development of quantum devices in a nanoelectromechanical system (NEMS). In this work, we first establish a fully quantum mechanical approach for transport through a NEMS device, which is valid for arbitrary bias voltages, temperatures, and electro-mechanical couplings. We find an anomalous current-electric field characteristics at a low bias, where the current decreases with a rising electric field, associated with the backward tunneling of electrons for a weak mechanical damping. We reveal that this intriguing behavior arises from a combined effect of mechanical motion and Coulomb blockade, where the rapid increase of backward tunneling events at a large oscillation amplitude suppresses the forward current due to prohibition of double occupation. In the opposite limit of strong damping, the oscillator dissipates its energy to the environment and relaxes to the ground state rapidly. Electrons then transport via the lowest vibrational state such that the net current and its corresponding noise have a vanishing dependence on the electric field.

Keywords: nano-electro-mechanical systems; open quantum systems; full counting statistics; electron shuttle

Permalink: https://www.hzdr.de/publications/Publ-41115


Data publication: Model-free Rayleigh weight from x-ray Thomson scattering measurements

Dornheim, T.; Bellenbaum, H.; Bethkenhagen, M.; Hansen, S.; Böhme, M.; Döppner, T.; Fletcher, L.; Gawne, T. D.; Gericke, D.; Hamel, S.; Kraus, D.; MacDonald, M.; Moldabekov, Z.; Preston, T.; Redmer, R.; Schörner, M.; Schwalbe, S.; Tolias, P.; Vorberger, J.

Abstract

This repository contains the raw data shown in the main text of the publication "Model-free Rayleigh weight from x-ray Thomson scattering measurements"

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Permalink: https://www.hzdr.de/publications/Publ-41114


Single atom counting of live interstellar radionuclides in natural archives

Lachner, J.

Abstract

Recent nearby supernovae and other cosmic explosions produce also long-lived radionuclides that penetrate into the solar system and are collected in terrestrial and lunar archives. Accelerator Mass Spectrometry (AMS) is used to identify minute amounts of these live radionuclides in environmental samples. Such signatures provide insight into the location and frequency of recent nearby Supernova activity and r-process events.

However, only in a few cases the proper combination of environmental archive and long-lived radionuclide allows to identify a clear fingerprint of such a rare input. Measurements of Supernova-produced 60Fe (T1/2=2.6 Myr) in deep-sea sediments and FeMn crusts as well as in lunar soil point to multiple Supernovae occurring in our solar vicinity within the past 10 Myr. Besides 60Fe, recently also the pure r-process nuclide 244Pu (T1/2=81 Myr) was detected in deep-sea archives demonstrating that r-process indeed occurred within the past few 100 Myr.

In this presentation, I will also discuss present technical constraints in the detection of such radionuclides by AMS and ongoing work increasing the capabilities for the analysis of additional interstellar radionuclides, e.g. 182Hf and 247Cm.

Keywords: radionuclides; Accelerator Mass Spectrometry

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  • Invited lecture (Conferences)
    DPG-Frühjahrstagung, Symposium Mass Matters: Prospects of Bridging Nuclear Physics, Mass Spectrometry, and Astrophysics, 10.-14.03.2025, Köln, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-41113


A consistent workflow for CFD simulations of gassed stirred tanks

Draw, M.; Greenshields, C.; Hänsch, S.; Krull, B.; Lehnigk, R.; Lucas, D.; Meller, R.; Schlegel, F.

Abstract

CFD simulations of gassed stirred tanks remain challenging for engineering practices due to complex geometries, rotating
components, and multifaceted interfacial phenomena. Effective case setups that serve engineering purposes require more than
the mere aggregation of existing CFD code functionalities, demanding substantial time and effort for development. This study
presents a consistent workflow for the simulation of stirred tanks, taking advantage of the recent developments in the open-
source CFD software distributed by OpenFOAM Foundation. A generic case demonstrates the workflow providing a foundational
setup for engineers and researchers to extend towards more complex scenarios. The work emphasizes the importance of
exemplary setups with varying degrees of complexity as an essential collection of knowledge.

Keywords: CFD; OpenFOAM; gas-liquid; stirred-tank; Euler-Euler; MultiMorph

  • Poster
    Jahrestreffen DECHEMA/VDI-Fachgruppen Mischvorgänge, Hochdruckverfahrenstechnik und Mehrphasenströmungen, 19.-21.03.2025, Hamburg, Germany

Permalink: https://www.hzdr.de/publications/Publ-41111


Temperature effects on the reduction of Se(VI) by natural pyrite

Wujian, J.; Mingliang, K.; Danwen, Q.; Jingye, S.; Huang, Z.; Lewen, S.; Qiaoya, L.; Hanyu, W.; Scheinost, A.; Prieur, D.

Abstract

79Se is a key radionuclide concerned in the geological disposal of high-level radioactive waste. Unlike lower valent Se(IV), previous studies have reported that the reduction of aqueous Se(VI) into insoluble Se0 or FeSe2 by pyrite is challenging under ambient temperatures. Considering the thermal environment of radioactive waste repositories and the widespread presence of pyrite in the host rocks, this study investigated Se(VI) reduction by natural arsenic-scarce and arsenic-rich pyrites, namely Py@TL and Py@LY, respectively, under conditions of pH ~2.0 to ~9.0 and temperatures ranging from 25 to 85 C. The results reveal that elevated temperatures and acidic conditions significantly enhance Se(VI) reduction to insoluble Se0, adhering to a pseudo-zero-order kinetic model. The apparent activation energy (Ea) values were determined to be 40.5  2.4 and 59.1  3.0 kJmol-1 for Se(VI) reduction by the arsenic-scarce Py@TL, and 51.0  1.8 and 63.2  12.6 kJmol-1 for the arsenic-rich Py@LY, at pH ~2.0 and ~2.5, respectively. These Ea values highlight surface chemical reactions as the rate-determining step, elucidating the inertness of Se(VI) on pyrite surfaces at ambient temperatures. Notably, arsenic impurities in Py@LY appear to enhance the reactivity by modifying the local structure of pyrite, but excessive Fe2+, As3+ competition, and solid layers of As0 and S0 impede the reduction process and elevate the apparent Ea. These findings provide novel insights into Se(VI) reduction mechanisms under complex geochemical conditions.

Keywords: Temperatures; Kinetics; Natural pyrite; Selenate reduction; Arsenic impurity

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Permalink: https://www.hzdr.de/publications/Publ-41110


Ferrous iron oxidation in the presence of antimonate at neutral pH: Mutual effects on iron mineral products and antimony sequestration

Wegner, L.; Burton, E. D.; McCammon, C.; Scheinost, A.; Planer-Friedrich, B.; Peiffer, S.; Hockmann, K.

Abstract

Antimony is a priority pollutant, whose mobility in redox-dynamic environments may be controlled by interactions with Fe(III) hydroxide minerals that form via Fe(II) oxidation. In this study, we examined the Fe(III) hydroxide precipitates and associated mechanisms of Sb(V) sequestration that result from Fe(II) oxidation in the presence of Sb(V) under neutral pH conditions. To achieve this aim, oxidation experiments were carried out in O2-saturated, Fe(II)-bearing solutions (buffered at pH 7) over a range of environmentally relevant Sb(V) concentrations (equivalent to Sb(V):Fe(II) molar ratios of 0, 0.01, 0.04, 0.1 and 0.25). Under these experimental conditions, Fe(II) oxidation occurred rapidly (within 20 minutes) causing associated removal of Sb(V) from solution via coprecipitation with the resulting Fe(III) hydroxides. At low Sb(V):Fe(II) ratios (< 0.1), lepidocrocite was the only Fe(III) mineral product of Fe(II) oxidation, whereas higher ratios resulted in formation of feroxyhyte. Both lepidocrocite and feroxyhyte retained Sb(V) within their crystal structure via Sb(V)-for-Fe(III) substitution. This mechanism of Sb(V) retention largely protected the solid-phase Sb(V) from release processes. Collectively, these results highlight the coupled role that interactions between Sb geochemistry and the Earth's near-surface Fe cycle can play in controlling both Fe(III) hydroxide mineralogy and Sb mobility.

Keywords: EXAFS; Feroxyhyte; Lepidocrocite; Mössbauer spectroscopy; Sb

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Permalink: https://www.hzdr.de/publications/Publ-41105


Experience with field emission at ELBE

Hallilingaiah, G.; Arnold, A.

Abstract

Field emission of electrons (unwanted emission of electrons from the surface) in SRF cavities is one of the critical issues faced during the operation of the cavities whcih limits its performance. We share our more than 2 decades of experience with field emission in the LINAC and gun cavity.

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  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    CM01 Field Emission Topical Meeting, 28.-29.01.2025, California, USA

Permalink: https://www.hzdr.de/publications/Publ-41104


Defect-induced magnetic symmetry breaking in oxide materials

Brand, E.; Rosendal, V.; Wu, Y.; Tran, T.; Palliotto, A.; Maznichenko, I. V.; Ostanin, S.; Esposito, V.; Ernst, A.; Zhou, S.; Park, D.-S.; Pryds, N.

Abstract

Magnetic properties of crystalline solids are fundamental to a wide range of applications, capturing the attention of a vast scientific community. Thus, engineering magnetic order in materials such as ferromagnetism and antiferromagnetism holds great scientific and technological interest. Defects such as vacancies, interstitials, and dopants induce local perturbations within the crystal lattice. These perturbations locally disturb the entire symmetry of crystals, resulting in symmetry breaking. Oxides, in particular, exhibit intriguing properties when subjected to defects, which can lead to significant modifications in their structural, electronic, and magnetic properties. Such defects in non-magnetic oxides can induce magnetic symmetry breaking, leading to the formation of emergent magnetic domains and orderings. In this review, we focus on the recent progress in magnetic breaking symmetries in materials via defect engineering and present our perspectives on how these may lead to new understanding and applications.

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Permalink: https://www.hzdr.de/publications/Publ-41103


Cerebral Perfusion Differences in the Visual Cortex and Fusiform Subregions Across the Psychosis Spectrum

Sritharan, J.; Zeng, V.; Petr, J.; Mutsaerts, H.-J.; Hoang, D.; Bolo, N.; Ivleva, E.; Dai, W.; Gershon, E.; Keedy, S.; Parker, D.; Trotti, R.; McDowell, J. E.; Clementz, B. A.; Tamminga, C. A.; Pearlson, G.; Keshavan, M. S.; Lizano, P.

Abstract

Background: Approximately 50% of individuals with psychosis spectrum disorders (PSD)
experience visual hallucinations and deficits in visual processing. Cerebral blood flow (CBF)
alterations have been identified in the occipital lobe (OL) and fusiform gyrus (FG) in PSD.
However, prior studies neither report on cytoarchitectonic subregions of the OL or FG, nor their
correlations with cognition. Moreover, perfusion differences across neurobiologically defined
psychosis Biotypes in these regions are not investigated yet.
Methods: ExploreASL and FreeSurfer were used to extract perfusion measures from pseudo-
continuous arterial spin labeling scans of visual (hOc1-hOc3v, middle temporal area (MT)) and
fusiform (FG2-FG4) subregions in 122 bipolar disorder with psychosis (BP), 179
schizoaffective disorder (SAD), 203 schizophrenia (SZ), and 350 healthy controls (NC), as well
as psychosis Biotypes (BT1-3). The data was adjusted for scanner effects using ComBat.
Analyses were co-varied for total gray matter CBF. We used R to perform statistical
comparisons across PSD and NC and across Biotypes. Partial Spearman correlation was
performed between CBF and cognitive measures. Benjamini & Hochberg correction was used
to correct for multiple comparisons.
Results: PSD exhibited greater perfusion in MT and FG2 compared to NC. Perfusion
significantly differed across psychosis Biotypes in hOc1 but not across diagnostic groups.
Higher MT and FG4 perfusion in PSD were associated with worse overall cognitive
performance.
Conclusions: Visual and fusiform subregions demonstrate significant perfusion
alterations which may indicate neurovascular deficits in PSD. Moreover, these perfusion
alterations may contribute to cognitive impairments and visual abnormalities in psychosis.

Involved research facilities

  • PET-Center

Permalink: https://www.hzdr.de/publications/Publ-41098


P2206 - Functionalized bisaminothiol derivatives, complexes with these bisaminothiol derivativesand use of said complexes as diagnostics and therapeutics

Fischer, S.; Ludwig, F.-A.; Ullrich, M.; Sihver, W.

Abstract

The invention relates to a compound of general formula I
(formula I)
wherein
A is a chelator selected from the group consisting of
k is independently at each occurrence 0, 1, or 2;
m is independently at each occurrence 1, 2, 3, 4 or 5;
n is independently at each occurrence 0, 1, 2 or 3;
p is independently at each occurrence 1, 2 or 3;
q is independently at each occurrence 1, 2 or 3;
u is independently at each occurrence 0 or 1;
X and Y are substituted or unsubstituted amino acids;
M 22 4 262 Application Text.docx
L is a bifunctional linker selected from group, consisting of
wherein v, x, and y are independently of each other 0, 1, 2, or 3 and z is 0, 1, 2 ,3, 4 or
5; and
R is H, methyl or ethyl.

  • Patent
    EP4282438 - Offenlegung 29.11.2023, Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-41096


Data publication: Synthesis of nonadentate ligand diethylene glycol-bis(3-aminopropyl ether)-N,N,N′,N′-tetraacetic acid DEGTA and its complexation behavior towards trivalent lanthanides and actinides

Friedrich, S.; Näder, A.; Drobot, B.; Kretzschmar, J.; Stumpf, T.; Barkleit, A.

Abstract

NMR-spectra of the pure title compound and its complexes with La(III), Sm(III), and Eu(III) at different metal-to-ligand ratios as well as pD values. TRLFS spectra of the title compound with Eu(III) as well as Cm(III). Measured and calculated IR spectra of the title compound and EDTA and EGTA with Eu(III). DFT calculations of the ligand with La(III), Eu(III), and Cm(III) as well as EDTA and EGTA comparisons.

Keywords: TRLFS; NMR; DFT; molecular structure; complex stability; f-element

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Permalink: https://www.hzdr.de/publications/Publ-41095


P2309 - Verfahren zur verbesserten, magnetisch unterstützten Abtrennung von Seltenen Erden

Lei, Z.; Ortmann, K.; Eckert, K.; Jähnigen, P.

Abstract

Die Erfindung betrifft ein Verfahren zur Abtrennung Seltener Erden aus einer festen oder einer wässrigen Phase mittels Lösungsmittelextraktion. Das Verfahren umfasst die Schritte: a) Kontaktieren einer wässrigen Phase (1) mit einer zweiten Phase (2), ausgewählt aus fester oder einer organischen flüssigen Phase, so dass aufgrund des Übergangs der Seltene Erden in Form von Seltenen-Erden-Ionen (3) von der zweiten oder in die zweite Phase ein Konzentrationsgradient innerhalb der wässrigen Phase entsteht, und b) Anlegen eines Magnetfelds (4) mittels eines Magneten (5) während des Kontaktierens an der Kontaktfläche, wobei das Magnetfeld so ausgerichtet wird, dass der Magnetfeldgradient antiparallel zum Konzentrationsgradienten der Seltenen Erden-Ionen in der wässrigen Phase ist und wobei das Produkt der Seltenen-Erden-abhängigen magnetischen Suszeptibilität χ und des Magnetfeldgradienten größer als 0,002 T2/m ist.

  • Patent
    DE102023122650 - Offenlegung 27.02.2025, Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-41093


Data publication: Chemical potential of the warm dense electron gas from ab initio path integral Monte Carlo simulations

Dornheim, T.; Bonitz, M.; Moldabekov, Z.; Schwalbe, S.; Tolias, P.; Vorberger, J.

Abstract

This repository contains the PIMC results from the publication "Chemical potential of the warm dense electron gas from ab initio path integral Monte Carlo simulations" as they are presented in the corresponding figures.

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Permalink: https://www.hzdr.de/publications/Publ-41090


A perspective on rhamnolipid metal complexation for application in bioionflotation

Chakankar, M. V.; Pawliszak, P.; Pollmann, K.; Krasowska, M.; Rudolph, M.

Abstract

Abstract
Objective: Many industrial wastewater streams contain various base and critical metals, which have to be removed, from the point of view of both environmental and economic reasons. Ion flotation is a simple physicochemical separation process for such streams. The process requires addition of surface active chemicals such as frothers that generate foam and collectors that collect metal ions. The separation efficiency of ion flotation process is controlled by the collector surfactants. As a way towards green processes, ion flotation is being assessed for the use of environmentally friendly alternatives. In this context, there has been a recent surge of research on use of biosurfactants as flotation reagents. The primary interest of this research is to scrutinize the useability of biosurfactants as ecofriendly ionflotation reagents and provide an insight into metal complexation and selectivity. This work is a part of our research aiming to develop a fundamental understanding of biosurfactants metal interactions.
Rhamnolipids are a group of glycolipid type of biosurfactants containing one or two rhamnose sugars attached to two beta hydroxyl fatty acid chains and produced by various strains of Pseudomonas species. The properties of rhamnolipid as ion collectors, like surface and interfacial activity and metal complexation ability for various base and critical metals are investigated with dynamic surface tension studies and isothermal titration calorimetry (ITC), in order to advance their application in bioionflotation process.
Results: The influence of various metals ions (Ga, As, Al, Mn, Ni, Co and Li) on surface activity of rhamnolipid revealed significant impact. Presence of metals ions shifted the surface activity curve of rhamnolipid. This change in trend can be attributed to the complexation of rhamnolipid with metal ions that lead to longer diffusion at the sub-surface and then to interface resulting in higher surface ages. Further, the shifting of surface tension curves of rhamnolipid is different for various tested metals, with Al being farthest followed by Ga and other metals. However, the surface tension curve for rhamnolipid in presence of As and Li alone does not show this behavior suggesting no complexing interaction of rhamnolipid with these metal ions. The difference in shifting of the curves with different metals shows that such surface tension studies in presence and absence of ions could provide an indirect suggestion on the possible selectivity or preference for complexation between different metal ions by surface active agent. Additionally, the rhamnolipid-metal complexation was evaluated using ITC to determine the thermodynamic characterization of the interaction of rhamnolipid with metal ions. The results show high binding affinity for metals as Ga>Mn>Ni>Co, suggesting the complexation. Moreover, ITC data also showed that rhamnolipid did not interact with Li and As, thus supporting the surface tension results. We will also discuss experimental findings of recent interaction studies at the Synchrotron in Melbourne, Australia.
Conclusion: The role of rhamnolipid as ion collector in the ion flotation process was assessed in the current study. In particular, our results revealed that the rhamnolipid showed the high affinity towards Al and Ga followed by other base metals, whereas no interaction was observed with As and Li. Further, the binding affinity results from ITC supported the surface activity results. Overall, the proposed approach of studying the effect of metal ions on surface activity and determining the binding affinity using ITC enables a better description of the possible selectivity of metals in mixed metal solutions and can be used during the design of flotation experiments.

Keywords: Rhamnolipid; Metal complexation; Biosurfactants; Environmentally-friendly

  • Lecture (Conference)
    Jahrestreffen der DECHEMA/VDI-Fachgruppen Gasreinigung, Mechanische Flüssigkeitsabtrennung, Grenzflächenbestimmte Systeme und Prozesse 2025, 06.-07.03.2025, Frankfurt, Germany

Permalink: https://www.hzdr.de/publications/Publ-41088


P2310 - Wärmespeicher

Unger, S.; Hampel, U.

Abstract

Die Erfindung betrifft einen Wärmespeicher zum Speichern thermischer Energie, wobei der Wärmespeicher eine Speicherelement-Anordnung mit einem oder mehreren Kombinations-Wärmespeicherelementen aufweist, wobei jedes der Kombinations-Wärmespeicherelemente ein aus einem Festkörpermaterial bestehendes Festkörper-Wärmespeicherelement aufweist, in
dem ein oder mehrere mit einem Phasenwechselmaterial befüllte Hohlräume ausgebildet sind.

  • Patent
    DE102023123958 - Offenlegung 06.03.2025, Nachanmeldungen: WO

Permalink: https://www.hzdr.de/publications/Publ-41085


Data publication: Electrolyte spraying within H2 bubbles during water electrolysis

Bashkatov, A.; Bürkle, F.; Demirkır, Ç.; Ding, W.; Sanjay, V.; Babich, A.; Yang, X.; Mutschke, G.; Czarske, J.; Lohse, D.; Krug, D.; Büttner, L.; Eckert, K.

Abstract

Description of Data availability.zip:

The archive contains raw data necessary for reproducing all figures presented in the manuscript submitted as Electrolyte spraying within H2 bubbles during water electrolysis (also available as a pre-print at https://doi.org/10.48550/arXiv.2409.00515). Each folder within the archive includes a readme file detailing data included (e.g. images, electrochemical data, or velocity fields).

Keywords: raw data; electrolysis; bubble dynamics; hydrogen; Worthington jet; droplets injection; end-pinching; Marangoni effect; internal flow; electrolyte spraying; hydrogen evolution reaction

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Permalink: https://www.hzdr.de/publications/Publ-41084


Data publication: Measurement of liquid foam flow through a diverging nozzle

Skrypnik, A.; Lappan, T.; Knüpfer, L.; Ziauddin, M.; Arnal Tribaldos, I.; Shevchenko, N.; Heitkam, S.

Abstract

The hydrodynamic theory of pneumatic foam analytically predicts the advective transport of liquid by foam rising continuously in a vertical column or pipe, relying on cross-sectional averaging of the foam velocity and liquid fraction. This experimental study accumulates a database for assessing the pneumatic foam theory in a vertically aligned diverging nozzle, i.e. at increasing cross-sectional area in nominal flow direction. The velocity distribution of the flowing foam and its liquid fraction distribution were measured by means of X-ray, optical and electrical techniques in three different nozzles distinguished by their half angle θ = 5°, 10°, 20°. The experimental setup and the measurements are described in detail in Skrypnik et al. (https://www.hzdr.de/publications/Publ-41024).

  • X-ray radiography (XR) has measured the distribution of the liquid fraction (εXR) inside the nozzle as a two-dimensional projection, i.e. integrated in the X-ray beam direction.
  • X-ray particle tracking (XPTV) has measured the local velocity uT inside the nozzle, along the motion path of each tracer particle described by the radial (r) and vertical position (z) in consecutive frames. The velocity uT was normalised by the superficial gas velocity jg(z) = Qg / (π * R(z)2), with Qg denoting the gas flow rate of compressed air applied for foam generation, and R(z) denoting the radius of the cross-sectional area depending on the vertical position z. To compare different nozzles, the vertical position z was normalised by the total length L = 25 mm / tan(θ) of the nozzle depending on its half angle θ = 5°, 10°, 20°.
  • Optical PIV adapted to foam (FoamPIV) has measured the time-averaged velocity uW through the transparent wall of the nozzle, i.e. at the nozzle radius r = R(z) depending on the vertical position z. As described above, the velocity uW was normalised by the superficial gas velocity jg(z), and the vertical position z was normalised by the total length L of the nozzle.
  • Electrode pairs (EP) have measured the cross-sectional average values of the liquid fraction (εEP) upstream and downstream the nozzle, simultaneously to the X-ray radiographic measurement of the liquid fraction distribution (εXR) inside the nozzle.

The experimental data in this repository is structured into different folders and files as follows.

  • FoamNozzle_Overview.CSV gives an overview of all measurements runs, nozzles, and techniques.
  • Level 1 are folders classified by the measurement technique: 01_XR: X-ray radiography, 02_XPTV: X-ray particles tracking velocimetry, 03_FoamPIV: Optical PIV adapted to foam, 04_EP: Electrode pairs.
  • Level 2 are folders classified by the different nozzles, distinguished by the nozzle half angle θ = 5°, 10°, 20°, and divided into bottom and top part in the case of θ = 5°, 10°.
  • Level 3 are TIF and CSV files of measurement results.
    • 01_XR: Each TIF image shows the time-averaged distribution of the liquid fraction inside the nozzle; the liquid fraction (0 < εXR < 1) is indicated by the value of each pixel.
    • 02_XPTV: Each CSV file consists of three columns, namely the radial position (r, in mm), the normalised vertical position (z / L), and the normalised velocity (uT / jg(z)).
    • 03_FoamPIV: Each CSV file consists of two columns, namely the normalised vertical position (z / L), and the normalised velocity (uW / jg(z)).
    • 04_EP: Each CSV file consists of three columns, namely the cross-sectional average of the liquid fraction (0 < εEP < 1) downstream as well as upstream the nozzle, and the time (in s).

Keywords: Drainage; Liquid fraction; Particle tracking velocimetry; Particle image velocimetry; Pneumatic foam theory; X-ray radiography

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Permalink: https://www.hzdr.de/publications/Publ-41083


Data publication: Non-van der Waals Heterostructures

Nihei, A.; Barnowsky, T.; Friedrich, R.
Researcher: Nihei, Anastasiia; Project Member: Barnowsky, Tom; Project Leader: Friedrich, Rico

Abstract

This dataset includes the primary research data for the publication "Non-van der Waals Heterostructures".

Keywords: 2D materials; non-van der Waals compounds; heterostructures; interface design; magnetism; data-driven research; computational materials science; high-throughput computing

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-41082


Dataset for ESFR-SIMPLE Task 3.3 (D3.3)

Fridman, E.

Abstract

This dataset contains the complimentary data for the deliverable D3.3:

  • Region- and batch-wise burnup data at EOEC in MWd/kg
  • DH data in Watts: up to 1.0E+07 sec for all 36 burnable materials described in Section ‎3.2
  • 3D power maps in Watts: SA-wise data subdivided into 19 axial layers
  • Detailed nuclide compositions of all burnable materials (number densities) at EOEC in #/barn‧cm.

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Permalink: https://www.hzdr.de/publications/Publ-41081


Extending and applying automated HERMES software publication workflows

Kernchen, S.; Meinel, M.; Druskat, S.; Fritzsche, M.; Pape, D.; Bertuch, O.

Abstract

Research software is an important output of research and must be published according to the FAIR Principles for Research Software. This can be achieved by publishing software with metadata under a persistent identifier. HERMES is a tool that leverages continuous integration to automate the publication of software with rich metadata. In this work, we describe the HERMES workflow itself, and how to extend it to meet the needs of specific research software metadata or infrastructure. We introduce the HERMES plugin architecture and provide the example of creating a new HERMES plugin that harvests metadata from a metadata source in source code repositories. We show how to use HERMES as an end user, both via the command line interface, and as a step in a continuous integration pipeline. Finally, we report three informal case studies whose results provide a preliminary evaluation of the feasibility and applicability of HERMES workflows, and the extensibility of the hermes software package.

Keywords: research software; software publication; software metadata; automation

Permalink: https://www.hzdr.de/publications/Publ-41080


Compared Experiences from Teaching Full-Semester Research Software Engineering Courses at Four German Universities

Bertrand, N.; Devkate, A.; Juckeland, G.; Linxweiler, J.; Peters, S.; Remus, S.; Schöning-Stierand, K.; Lamprecht, A.-L.

Abstract

Research Software Engineering has emerged as a critical discipline atthe intersection of software development and research with the aim of enhancingthe quality, reliability, and reproducibility of scientific software. In this paper wepresent a comparative analysis of the experiences gained from teaching full-semesterResearch Software Engineering (RSE) courses at four different universities in Ger-many. Despite its growing importance, there is limited literature on the pedagogicalapproaches and challenges encountered in teaching RSE courses, particularly at theuniversity level. This paper investigates and contrasts the contexts, designs, andexperiences of RSE courses offered at the TU Braunschweig, TU Dresden, Uni-versity of Hamburg and University of Potsdam. By synthesizing the experiencesand insights gleaned from these four universities, this study aims to provide valu-able guidance and best practices for educators seeking to develop or enhance RSEeducation initiatives.

Keywords: Research Software Engineering; Scientific Software Engineering; RSE Education; RSE Teaching

Permalink: https://www.hzdr.de/publications/Publ-41079


Enhanced triplet superconductivity in next-generation ultraclean UTe2

Wu, Z.; Weinberger, T. I.; Chen, J.; Cabala, A.; Chichinadze, D. V.; Shaffe, D.; Pospisil, J.; Prokleska, J.; Haidamak, T.; Bastien, G.; Sechovsky, V.; Hickey, A. J.; Mancera-Ugarte, M. J.; Benjamin, S.; Graf, D. E.; Skourski, Y.; Lonzarich, G. G.; Valiska, M.; Grosche, F. M.; Eaton, A. G.

Abstract

The unconventional superconductor UTe2 exhibits numerous signatures of spin-triplet superconductivity—a rare state of matter which could enable quantum computation protected against decoherence. UTe2 possesses a complex phase landscape comprising two magnetic field-induced superconducting phases, a metamagnetic transition to a field-polarized state, along with pair- and charge-density wave orders. However, contradictory reports between studies performed on UTe2 specimens of varying quality have severely impeded theoretical efforts to understand the microscopic origins of the exotic superconductivity. Here, we report a comprehensive suite of high magnetic field measurements on a generation of pristine quality UTe2 crystals. Our experiments reveal a significantly revised high magnetic field superconducting phase diagram in the ultraclean limit, showing a pronounced sensitivity of field-induced superconductivity to the presence of crystalline disorder. We employ a Ginzburg–Landau model that excellently captures this acute dependence on sample quality. Our results suggest that in close proximity to a field–induced metamagnetic transition the enhanced role of magnetic fluctuations—that are strongly suppressed by disorder—is likely responsible for tuning UTe2 between two distinct spin-triplet superconducting phases.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

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Permalink: https://www.hzdr.de/publications/Publ-41078


Recovering Knowledge from old Code

Erxleben, F.

Abstract

Imagine: A 30 year old Fortran code. 10K lines of three-letter variables, almost no commentary of varying correctness and no one left to remember how it works. Amazingly it is still in use - even though it is unclear how exactly it calculates what it calculates…

Somewhere buried in these dusty bits and bytes supposedly lies an algorithm that promises to be better than the tools that a research group have available, faster and more precise.

The HIFIS RSE-consulting team was approached to help with investigating this software, unlocking its hidden secrets and coming up with a way to deal with this kind of "inherited software", because we can be sure: There is a lot more where that came from.

In this talk we will present how we approach this problem, the plan, the steps already taken, the challenges encountered, what worked (or at least looks promising) and what didn't.

Keywords: RSE; Legacy Software; FORTRAN 77; HIFIS

Permalink: https://www.hzdr.de/publications/Publ-41077


Anomalous Quasielastic Scattering Contribution in the Centrosymmetric Multi-q Helimagnet SrFeO3

Andriushin, N. D.; Grumbach, J.; Kulbakov, A. A.; Tymoshenko, Y. V.; Onykiienko, Y. A.; Firouzmandi, R.; Cheng, E.; Granovsky, S.; Skourski, Y.; Ollivier, J.; Walker, H. C.; Kocsis, V.; Büchner, B.; Keimer, B.; Doerr, M.; Inosov, D. S.; Peets, D. C.

Abstract

Centrosymmetric compounds which host three-dimensional topological spin structures comprise a distinct subclass of materials in which multiple-q magnetic order is stabilized by anisotropy and bond frustration in contrast to the more common path of antisymmetric exchange interactions. Here we investigate static and dynamic magnetic properties of the cubic perovskite SrFeO3—a rare example of a centrosymmetric material hosting two types of topological spin textures: skyrmionlike and hedgehoglattice phases. Our detailed magnetization and dilatometry measurements describe the domain selection processes and phase transitions in SrFeO3. Spin excitations are investigated using inelastic neutron scattering for all three zero-field phases. In the higher-temperature ordered phases, high-energy magnons increasingly lose coherence, so that spin fluctuations are dominated by a distinct quasielastic component at low energies. We anticipate that this could be generic to symmetric helimagnets in which the chiral symmetry is spontaneously broken by the magnetic order.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)

Permalink: https://www.hzdr.de/publications/Publ-41076


Giant quantum oscillations in thermal transport in low-density metals via electron absorption of phonons

Bermond, B.; Wawrzynczak, R.; Zherlitsyn, S.; Kotte, T.; Helm, T.; Gorbunov, D.; Gu, G.; Li, Q.; Janasz, F.; Meng, T.; Menges, F.; Felser, C.; Wosnitza, J.; Grushin, A.; Carpentier, D.; Gooth, J.; Galeski, S.

Abstract

Oscillations of conductance observed in strong magnetic fields are a striking manifestation of the quantum dynamics of charge carriers in solids. The large charge carrier density in typical metals sets the scale of oscillations in both electrical and thermal conductivity, which characterize the Fermi surface. In semimetals, thermal transport at low-charge carrier density is expected to be phonon dominated, yet several experiments observe giant quantum oscillations in thermal transport. This raises the question of whether there is an overarching mechanism leading to sizable oscillations that survives in phonon-dominated semimetals. In this work, we show that such a mechanism exists. It relies on the peculiar phase-space allowed for phonon scattering by electrons when only a few Landau levels are filled. Our measurements on the Dirac semimetal ZrTe5 support this counterintuitive mechanism through observation of pronounced thermal quantum oscillations, since they occur in similar magnitude and phase in directions parallel and transverse to the magnetic field. Our phase-space argument applies to all low-density semimetals, topological or not, including graphene and bismuth. Our work illustrates that phonon absorption can be leveraged to reveal degrees of freedom through their imprint on longitudinal thermal transport.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Open Access Logo Proceedings of the National Academy of Sciences of the United States of America 122(2025)10, 2408546122
    DOI: 10.1073/pnas.2408546122
    arXiv: https://arxiv.org/abs/2402.17022

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Permalink: https://www.hzdr.de/publications/Publ-41074


Superconducting critical temperature elevated by intense magnetic fields

Wu, Z.; Chen, H.; Weinberger, T. I.; Cabala, A.; Graf, D. E.; Skourski, Y.; Xie, W.; Ling, Y.; Zhu, Z.; Sechovsky, V.; Valiska, M.; Grosche, F. M.; Eaton, A. G.

Abstract

Below a critical temperature Tc, superconductors transport electrical charge without dissipative energy losses. The application of a magnetic field B generally acts to suppress Tc, up to some critical field strength at which Tc -> 0 K. Here, we investigate magnetic field–induced superconductivity in high-quality specimens of the triplet superconductor candidate UTe2 in pulsed magnetic fields up to B = 70 T. Strikingly, we find that this material has a higher Tc when B > 40 T (Tc ≈ 2.4 K) than it does for B = 0 T (Tc = 2.1 K). This observation points to a fundamentally distinct mechanism for the formation of superconductivity at high B in Ute2 compared to the case of B = 0 T.

Involved research facilities

  • High Magnetic Field Laboratory (HLD)
  • Open Access Logo Proceedings of the National Academy of Sciences of the United States of America 122(2025)2, 2422156122
    DOI: 10.1073/pnas.2422156122

Permalink: https://www.hzdr.de/publications/Publ-41073


Host–guest chemistry on living cells enabling recyclable photobiocatalytic cascade

Zhang, J.; Batista, V. F.; Hübner, R.; Karring, H.; Wu, C.

Abstract

Combining chemical and whole-cell catalysts enables sustainable chemoenzymatic cascade reactions. However, their traditional combination faces challenges in catalyst recycling and maintaining cell viability. Here, we introduce a supramolecular host–guest strategy that efficiently attaches photocatalysts to bacterial cells, facilitating recyclable photobiocatalysis. This method involves attaching a cationic polyethylenimine (PEI) polymer, functionalized with beta-cyclodextrin (beta-CD), to E. coli cells. The polymer attachment is biocompatible and protective, safeguarding the cells from harsh conditions such as UV radiation and organic solvents, without causing cell death. Additionally, the presence of beta-CD imparts a plug-and-play capability to the cells, enabling the straightforward integration of guest photocatalysts – specifically anthraquinone – onto the cell surface through host–guest interactions. This effective combination of cellular and chemical catalysts promotes efficient photobiocatalytic cascades and supports the photocatalyst's recycling and reuse. This supramolecular system thus represents a promising platform for advancing photobiocatalysis in cascade synthesis.

Involved research facilities

Related publications

Permalink: https://www.hzdr.de/publications/Publ-41072


Protein Modifications and Ionic Strength Show the Difference in Protein-Mediated and Solvent-Mediated Regulation of Biomolecular Condensation

Czajkowski, A.; Udayabanu, A.; Raj, M.; Pulibandla, L. C. P.; Tursunovic, M.; Jahnel, M.; Adams, E.

Abstract

Biomolecular condensation is an important mechanism of cellular compartmentalization without membranes. Formation of liquid-like condensates of biomolecules involves protein-protein interactions working in tandem with protein-water interactions. The balance of these interactions in condensate-forming proteins is impacted by multiple factors inside of a living organism. This work investigates the effects of post-translational modifications (PTMs) and salt concentration as two such perturbing factors on the protein Fused in Sarcoma (FUS), an RNA binding protein. The protein was obtained from two expression systems differing by their capability to add PTMs to the protein, bacterial and insect cell. Attenuated total reflection Terahertz spectroscopy is used to probe the solvation behavior in condensates formed from FUS protein with and without PTMs at 100 mM and 2.5 M KCl. The results show that while PTMs impact the phase-separating propensity, they do not alter protein solvation in the condensate. On the other hand, salt concentration was found to alter the stiffness of the water hydrogen bond network. These findings have implications for biomolecular condensates chemistry, showing that condensate molecular organization is perturbed by fluctuations in solvent properties.

Keywords: biomolecular condensates; protein solvation

Permalink: https://www.hzdr.de/publications/Publ-41071


How to find and evaluate good research software - a field report

Konrad, U.; Bruch, C.

Abstract

The Helmholtz Association strongly promotes the field of research software engineering. Among other activities, the Helmholtz Research Software Directory (RSD) was developed and the Helmholtz Software Award was launched. But these great initiatives have raised questions:

How exactly do you find the great software?
How do you encourage the development teams to publish it and describe it in such a way that not only insiders understand what it's all about?
How can international reviewers be recruited and how can they evaluate software applications in areas they are not specialized on?
How do you compare and evaluate software that differs greatly not only in terms of technical aspects, but also in terms of maturity, user community and target groups?

The Helmholtz RSD has developed into a successful repositoiry and is increasingly bringing added value to software developers and scientists. The first Helmholtz Software Prize 2023 was awarded in three categories and the applications for the second call 2024 have been received and are being reviewed. At the same time the topic of evaluating research results, including data and software, has recently become increasingly important. Here too, the evaluation of research software is playing an important role.

In this presentation, the experiences and results of these processes will be presented in detail. The topics mentioned and still in flux are of growing importance for universities, research institutions and also the NFDI consortia! These experiences in this still relatively new field are therefore valuable information and a basis for discussions in the RSE community!

Keywords: Research Software Engineering; RSE; Research Software Repository; Software Award; Evaluation

Involved research facilities

  • Data Center

Permalink: https://www.hzdr.de/publications/Publ-41070


Tungsten oxide thin films probed by depth-resolved positron annihilation spectroscopy

Burwitz, V. V.; Kärcher, A.; Mathes, L.; Book, A.; Paul, N.; Schwarz-Selinger, T.; Butterling, M.; Hirschmann, E.; Liedke, M. O.; Wagner, A.; Unsal, E.; Cuniberti, G.; Hugenschmidt, C.

Abstract

Tungsten oxide (WOx) films grown on tungsten (W) are characterized by depth-resolved Doppler-broadening spectroscopy (DBS) and positron-annihilation lifetime spectroscopy (PALS) as primary analytical methods. The WOx films are prepared on W(111) monocrystals using either exposure to air, electrochemical, or thermal oxidation procedures, chosen according to the desired thickness. We calculate the lifetime of positrons in the bulk of WOx and in different types of vacancies using the atomic superposition (AtSup) method. These give the size required for a multivacancy in WOx needed for it to be identifiable by PALS. In our experiments, we identified a distinct positron lifetime of 325 p⁢s in the thin oxide layer on W exposed to air. This value overlaps with that of multivacancy sites in W and, hence, should be taken into account in future PALS studies of radiation-induced defects in W.

Keywords: Defects; Radiation damage; Vacancies; Oxides; Thin films; Transition metal oxides; Doppler broadening spectroscopy; Positron annihilation spectroscopy; X-ray diffraction

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-41069


Data publication: Free volume and nonlinear viscoelasticity in supercrystalline nanocomposites: A nanoindentation driven modelling analysis

Yan, C.; Hirschmann, E.; Geers, G. D. M.; Giuntini, D.

Abstract

This data set consists of positron annihilation lifetime measurements generated at a conventional measuring station with a Na-22 source.

Keywords: Supercrystals; Creep; Nonlinear viscoelasticity; Free volume; Positron annihilation lifetime spectroscop

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Permalink: https://www.hzdr.de/publications/Publ-41068


Free volume and nonlinear viscoelasticity in supercrystalline nanocomposites: A nanoindentation driven modelling analysis

Yan, C.; Hirschmann, E.; Geers, G. D. M.; Giuntini, D.

Abstract

Supercrystalline nanocomposites (SCNCs) are a new class of hybrid materials consisting of organically functionalized nanoparticles that are arranged into periodic architectures, featuring multi-functional properties. While their mechanical behavior is starting to be assessed, the time-dependent aspects thereof, and especially creep, remain unexplored. This lack of understanding is an obstacle towards future implementation of SCNCs into devices. It is therefore imperative not only to capture experimentally the creep behavior of SCNCs, but also to develop models that accurately predict its evolution. Here, a model is proposed to capture the nanoindentation creep behavior of SCNCs, using both rheological models and free volume theory. The creep compliance derived from the rheological model shows a stress-dependent trend, indicating nonlinear viscoelasticity. The presence of free volume is experimentally detected in SCNCs via positron annihilation lifetime spectroscopy. It decreases in size with increasing degrees of crosslinking of the organic phase, a phenomenon attributed to the shrinkage of superlattices. The creep compliance is predicted by introducing a shift factor to account for the evolution of the relaxation time caused by the change in free volume. A free volume-based creep model is proposed to predict the creep behavior of SCNCs, and its applicability is validated through new nanoindentation creep tests at varying loads.

Keywords: Supercrystals; Creep; Nonlinear viscoelasticity; Free volume; Positron annihilation lifetime spectroscop

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Permalink: https://www.hzdr.de/publications/Publ-41067


Defect Analysis of Gamma Gallium Oxide

Bektas, U.; Liedke, M. O.; Liu, H.; Ganss, F.; Butterling, M.; Klingner, N.; Hübner, R.; Makkonen, I.; Wagner, A.; Hlawacek, G.
Researcher: Chekhonin, Paul; Researcher: Worbs, Andreas; Project Member: Hlawacek, Gregor; Project Member: Wagner, Andreas

Abstract

In this study, we investigate the ion-induced phase transition in gallium oxide (Ga2O3) from beta- to the gamma- phase and the role of defects in the transformation and the quality of the resulting crystal structure. This upload contains XRD, TEM, RBS, PALS, DB-VEPAS and simulations.

Keywords: Gallium Oxide; Defects in Gallium Oxide; Positron Annihilation Lifetime Spectroscopy; Doppler broadening spectroscopy; X-ray diffraction; Transmission Electron Microscopy

Involved research facilities

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Permalink: https://www.hzdr.de/publications/Publ-41066


Technetium - The Unknown Center of the Periodic Table

Strub, E.; Badea, D.; Bruns, J.; Frontera, A.; Mayordomo, N.; Sakhonenkova, A.; Roca Jungfer, M.; Wickleder, M.; Yong, C.; Zegke, M.

Abstract

It took 78 years from Mendeleev’s proposal of an existence of “eka-manganese” (1869) until it was finally named as technetium (Tc) in 1937. Another 78 years have passed since then. This provides a good occasion to pinpoint what we know and what we still do not know of this radioelement. Technetium is placed near the center of the Periodic Table, in the center of the groups 6, 7, and 8. Some chemical properties of the elements surrounding technetium show trends within the columns or along the rows of the Periodic Table, but a consistent interpretation of these trends is lacking as long as the knowledge on technetium remains incomplete. This is especially remarkable as, on the other hand, the isotope 99mTc is applied on a daily basis in nuclear medicine. The aim of this paper is to review the fundamental understanding of technetium chemistry, mostly focusing on the research of the last decade,
its implications, and its future perspectives. These developments show a picture of growing connections between physicochemical data, fundamental inorganic chemistry, organometallic and coordination chemistry, computational chemistry, and geochemistry

Keywords: Technetium; Perspectives; geochemistry; coordination chemistry; organometallic chemistry; inorganic chemistry; computational chemistry

Permalink: https://www.hzdr.de/publications/Publ-41065


Helmholtz Quality Indicators for Software– & Data Products

Meistring, M.; Juckeland, G.

Abstract

The Helmholtz Association is adding a new indicator for research data and research software publications to its reporting. A working group with members from all Helmholtz centers has been working on defining this new indicator and the Helmholtz general assembly has approved their suggestion in its fall meeting of 2024. In this talk the indicator as well as the ideas behind it and the methods to collect the information are introduced. The indicator is based on a maturity model looking at various aspects of a research software publication, thus also providing value to the authors of the software and research software researchers as it makes multiple aspects of research software as a scientific publication itself visible.

  • Open Access Logo Invited lecture (Conferences)
    6. Helmholtz Research Software Forum, 12.-13.02.2025, Jülich, Deutschland
  • Open Access Logo Invited lecture (Conferences) (Online presentation)
    39th HIRSE Seminar, 21.02.2025, Jülich, Deutschland
  • Open Access Logo Lecture (Conference)
    deRSEcon25, 25.-27.02.2025, Karlsruhe, Deutschland

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Permalink: https://www.hzdr.de/publications/Publ-41064


Verification of nTRACER/COBRA-TF with Serpent2/SUBCHANFLOW for full core high fidelity high-resolution analysis of VVERs

Papadionysiou, M.; Bilodid, Y.; Fridman, E.; Pautz, A.; Hursin, M.

Abstract

This work illustrates the verification of the nTF/CTF multi-physics core solver for full core VVER-1000 analysis and more specifically the X2 benchmark. The coupled code system is compared with a solver of similar capabilities, Serpent2/SCF. The differences in the models and in the methods employed by the multi-physics core solvers are discussed in detail. Their impact is studied by comparing nTF/CTF with Serpent2/SCF for single VVER assembly calculations with different modeling options. Then, the two code systems are compared for the Hot Full Power (HFP) state of the X2 benchmark, which includes two phases, one with default modeling options for all codes, and one with consistent modeling options. Overall, nTF/CTF presents good agreement with Serpent2/SCF, in terms of power, temperature and boron concentration. The existing discrepancies can be partly attributed to the different methods and correlations used by the codes involved in the coupled code systems.

Keywords: High-resolution; Multi-physics; nTRACER; COBRA-TF; VVER

Involved research facilities

  • Data Center

Permalink: https://www.hzdr.de/publications/Publ-41062


Integration Strategies and Formats in Field-Effect Transistor Chemo- and Biosensors: A Critical Review

Janićijević, Ž.; Baraban, L.

Abstract

The continuous advances in micro- and nanofabrication technologies have inevitably led to major improvements in field-effect transistor (FET) design and architecture, significantly reducing component footprint and enabling highly efficient integration into many electronic devices. Combined efforts in the areas of materials science, life sciences, and electronic engineering have unlocked opportunities to create ultrasensitive FET chemo-and biosensor devices that are coupled with more diverse and complex integration requirements in terms of hardware interfacing, reproducible functionality, and handling of analyte samples. Integration of FET chemo- and biosensors remains one of the major bottlenecks in bridging the gap between fundamental research concepts and commercial sensing devices. In this review, we critically discuss different strategies and formats of integration in the context of key requirements, fabrication scalability, and device complexity. The intentions of this review are: 1) to provide a practical overview of successful FET sensor integration approaches, 2) to identify crucial challenges and factors limiting the extent of FET sensor integration, and 3) to highlight promising perspectives for future developments of FET sensor integration. We believe that our structured insights will be helpful for scientists and engineers of various profiles focusing on the design and development of FET-based chemo- and biosensor devices.

Keywords: field-effect transistor (FET); integration; multiplexing; sensor arrays; chemical sensors; biosensors; electronics; microfluidics; multisensor systems

Permalink: https://www.hzdr.de/publications/Publ-41061


Fully Degradable Impedimetric Sensor Based on Polycaprolactone/Molybdenum Composite Electrodes for α-Amylase Detection

Janićijević, Ž.; Davydiuk, N.; Makarov, D.; Besford, Q. A.; Baraban, L.

Abstract

Transient electronic sensing devices are essential for temporary healthcare monitoring, enabling timely diagnostics and eliminating risks associated with implant removal. With the growing emphasis on the circular economy, designing fully biodegradable or bioresorbable sensors has also emerged as a key strategy to mitigate electronic waste in healthcare applications. Electrochemical biosensors offer significant advantages for healthcare monitoring, combining simple construction and cost-efficiency with high sensitivity, fast response times, and straightforward data readout. These sensors are typically built with metal film electrodes patterned on an insulating substrate. However, when constructed from degradable materials and exposed to biofluids, electrochemical biosensors face challenges such as electromechanical instability, rapid or uneven dissolution, and ineffective surface functionalization which can compromise detection specificity. To address these limitations, we develop composite electrodes made from polycaprolactone (PCL) and molybdenum (Mo), materials chosen for their slow degradation rates under physiological conditions. The Mo/PCL composite provides stable, slow degradation in physiological conditions, creating a dependable interface for short-term electrochemical sensing when layered on an insulating PCL substrate. Based on this sensing interface concept, we fabricate a fully degradable impedimetric sensor using a scalable and cost-effective process that includes solution-based techniques (solvent casting, doctor blade coating, and immersion precipitation), laser cutting, and facile bonding methods such as hot press lamination and gluing. The sensor is optimized for detecting α-amylase, a biomarker relevant to pancreatic health, stress response, and certain metabolic disorders. Monitoring α-amylase levels is crucial both in vitro in extracted biofluids and in vivo near the resection and anastomosis sites following pancreatic surgery. Detection specificity is achieved by functionalizing the interdigitated Mo/PCL electrodes with an α-amylase-sensitive hydrogel coating made of modified phytoglycogen particles. This hydrogel forms a three-dimensional network that degrades in response to α-amylase in a controlled, concentration-dependent manner, and swells as crosslinking density decreases, causing measurable changes in impedance spectra. This measurement mechanism allows for the quantification of α-amylase across a wide range of concentrations (10¹–10⁵ U/L), covering levels relevant to various diagnostic scenarios, including potentially harmful enzyme leakage caused by pancreatic surgery. The distinct degradation time scales and profiles of Mo and PCL also allow residual PCL layers to be effectively upcycled for additional sensor fabrication without compromising functionality. We foresee opportunities to develop a variety of electrochemical sensors using similar strategies, adaptable to diverse measurement settings and environments.

  • Lecture (Conference)
    10th International Winter School on Bioelectronics (BioEl 2025), 14.-21.03.2025, Kirchberg in Tirol, Austria

Permalink: https://www.hzdr.de/publications/Publ-41059


Enhancing froth flotation of PEMEL catalyst particles for recycling by adding sodium hexametaphosphate

Ahn, S.; Rudolph, M.

Abstract

This study investigates the effect of dispersant on the froth flotation of representative polymer electrolyte membrane water electrolyzer (PEMEL) catalyst particles, specifically TiO2 and carbon black. Since the used material showed significant difference in their (de) wetting behavior, mechanical processes such as froth flotation can achieve selective separation of the particles. In the previous research on liquid-liquid particle separation, SHMP significantly improved the dispersion ability of TiO2, alleviating stabilization at the interface and enhancing its recovery. Hence, sodium hexametaphosphate (SHMP) is proposed to address the challenge of hydrophilic TiO2 entrainment in the froth phase.
Both pristine particles and ionomer-containing particles were prepared for the test. The behaviour of the synthesized particles represents that of real particles from the cell in the system. The amphiphilic structure of ionomer significantly influenced particle separation based on wettability differences. Moreover, to overcome the limitation of ultrafine particles in froth flotation, a hydrophobic double emulsion was used to selectively agglomerate carbon black particles.
SHMP improved the recovery and grade of both particles effectively by stabilizing TiO2 in the particle dispersion and preventing its undesired recovery in the froth phase.
While many studies focus on chemical processes for PGMs recovery, the approach with mechanical separation methods present a more sustainable recycling strategy for PEM water electrolyzers.

  • Lecture (Conference)
    Jahrestreffen der DECHEMA/VDI-Fachgruppen Gasreinigung, Mechanische Flüssigkeitsabtrennung, Grenzflächenbestimmte Systeme und Prozesse, 06.-07.03.2025, Frankfurt am Main, Germany

Permalink: https://www.hzdr.de/publications/Publ-41057


hMtMrFoam - Heat and Mass Transport Multiregion Solver

Personnettaz, P.; Weber, N.

Abstract

The software repository contains a solver to model heat and mass transfer in several regions with OpenFOAM. Heat transport is modelled in the full domain, while fluid dynamics is solved in each layer separately. Mass transfer is simulated only in the bottom layer. The dataset further contains a testcase of a Li-Bi liquid metal battery.

Related publications

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Permalink: https://www.hzdr.de/publications/Publ-41056


NAPMIX - Nuclear, Astroparticle, and Particle Physics Metadata Integration for eXperiments

Knodel, O.; Mistry, A. K.

Abstract

The NAPMIX project aims to create a cross-domain metadata schema tailored for the Nuclear, Astro, and Particle Physics communities. By leveraging local and international connections, including Open Science initiatives like EOSC, EURO-LABS, and the ESCAPE Cluster, NAPMIX will foster synergies with related fields, enhancing cross-domain interoperability. The schema will facilitate the sharing and long-term findability of datasets, representing a breakthrough in Open Science within experimental physics. Community feedback will be integral to refining the schema, ensuring its relevance and sustainability.

Keywords: Metadata; ESCAPE; NAPMIX; Nuclear Physics; Astroparticle Physics; Particle Physics; Ontology

Involved research facilities

  • Felsenkeller
  • Open Access Logo Invited lecture (Conferences)
    1st OSCARS Annual General Meeting, 03.-04.03.2025, Rome, Italy

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Permalink: https://www.hzdr.de/publications/Publ-41055


Data publication: Development of [99mTc]TcO-ABX474: Design, Synthesis and biological Evaluation of PSMA-binding Technetium-99m radioligands for SPECT Imaging of Prostate Cancer

Lis, C.; Ludwig, F.-A.; Fischer, S.; Ullrich, M.; Lankau, H.-J.; Sihver, W.; Gündel, D.; Joseph, D.; Meyer, C.; Kopka, K.; Pietzsch, J.; Brust, P.; Hoepping, A.

Abstract

Daten zur Radiosynthese der Tracer, einschließlich analytische Daten Daten zu Stabilitätsprüfungen der Tracer Daten zur biologischen Evaluierung (Autoradiographie)

Related publications

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Permalink: https://www.hzdr.de/publications/Publ-41054


Data publication: OECD/NEA AI/ML Benchmark on Critical Heat Flux—HZDR Results

Nikitin, E.

Abstract

Results obtained in the framework of OECD/NEA Benchmark on Artificial Intelligence and Machine Learning for Scientific Computing in Nuclear Engineering—Phase 1: Critical Heat Flux

Keywords: Critical Heat Flux; CHF; OECD/NEA Benchmark; Artificial Intelligence; Look-up Table

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Permalink: https://www.hzdr.de/publications/Publ-41051


Elucidation of Vanadium Recovery from Linz-Donawitz Converter Slag through Acid Leaching and Solvent Extraction

Viswamsetty, L. K.; Kelly, N.; Fischer, U.; Väisänen, A. O.; Patil, A. B.

Abstract

Vanadium plays a pivotal role in various cutting-edge applications, from strengthening steel to enabling renewable energy storage through vanadium redox flow batteries, among others. Among all sources, vanadium recovery from LD converter slags has proven to be one of the best secondary resources. However, recovery from low-grade (approximately 2-3% vanadium) LD converter slags remains challenging due to their complex composition and low vanadium content. In contrast, high-grade slags (10-12% vanadium) are processed through energy-intensive pyrometallurgical routes. Therefore, conventional methods for vanadium recovery from low-grade LD converter slags are neither economically viable nor environmentally friendly, highlighting the need for sustainable hydrometallurgical alternatives2,3.

The present study investigates a hydrometallurgical approach involving acidic leaching and solvent extraction to efficiently recover vanadium from low-grade slags, examining the influence of various parameters, such as acid concentration, pulp density, particle size, and leaching time. The study shows that the exothermic reaction positively influences leaching efficiency, achieving about 80-95% vanadium recovery under specific conditions. Following leaching, solvent extraction using the acidic extractant diethylhexyl phosphate (D2EHPA) achieves over 80% vanadium recovery with negligible iron co-extraction. In the subsequent stripping stage, controlled acid concentrations are applied to successfully remove iron, yielding a vanadium-enriched solution of 98% purity suitable for vanadium pentoxide synthesis.

This work highlights the feasibility of hydrometallurgical methods in bridging the vanadium supply gap, offering both economic and environmental benefits while contributing to a sustainable future for the steel industry.

Keywords: Vanadium; Steel Slag; LD Slag; Hydrometallury; Acid Leaching; Solvent Extraction

Involved research facilities

  • Metallurgy Technical Centre
  • Poster
    Annual Meeting of the DECHEMA /VDI Group Extraction 2025, 19.-20.02.2025, Aachen, Germany

Permalink: https://www.hzdr.de/publications/Publ-41048


Impact of DTPA and 3,4,3-LI(1,2-HOPO) on EuIII interactions with renal cells in vitro

Senwitz, C.; Vogel, M.; Drobot, B.; Stumpf, T.; Heller, A.

Abstract

This study represents a first comprehensive investigation on how the decorporation agents CaNa3-DTPA (DTPA) and 3,4,3-LI(1,2-HOPO) (LIHOPO) affect EuIII interactions with human and rat kidney cells in vitro. Cell biological investigations were complemented with physicochemical measurements to correlate cytotoxic impairments with intracellular metal uptake and EuIII speciation.
Upon exposure to sole DTPA or LIHOPO, cell viability and morphology are affected in a time- and concentration-dependent manner. For both decorporation agents, detailed EC50 values for renal cells in vitro are reported. Simultaneous application of EuIII + DTPA in the medium leads to formation of the soluble and largely cell impermeable EuDTPA2− complex. At ligand excess, this significantly reduces intracellular EuIII uptake. However, EuDTPA2− was spectroscopically detected also inside cells indicating that small fractions of this complex are able to pass the plasma membrane. When EuIII + LIHOPO is applied to the medium, the soluble EuLIHOPO− complex is formed. In contrast to DTPA, this drastically enhances intracellular EuIII uptake even at ligand deficit demonstrating that EuLIHOPO− is highly cell permeable. Concomitantly, this complex was spectroscopically detected inside cells confirming its plasma membrane passage and intracellular stability. Nevertheless, due to stable EuIII binding, the cell viability is not influenced by the increased intracellular EuIII content. In fact, the applied ligand concentration is much more critical in this regard, emphasizing the need for cytotoxic investigations.
Our results improve the knowledge of the cellular interactions of lanthanides ± decorporation agents and demonstrate the combination of in vitro cell culture and spectroscopy being a sophisticated toolbox for this.

Keywords: Lanthanides; Decorporation agents; Kidney cells; Cytotoxicity; Intracellular uptake; Heavy metal speciation

Permalink: https://www.hzdr.de/publications/Publ-41047


Data publication: Generating structured foam via flowing through a wire array

Skrypnik, A.; Knüpfer, L.; Trtik, P.; Lappan, T.; Ziauddin, M.; Heitkam, S.

Abstract

The structure of liquid foam is generally considered random and isotropic. However, when foam flows past a set of wires, an inhomogeneous liquid fraction distribution, or layering, can be observed within the bulk. This dataset presents neutron radiography data of foam flowing past a set of thin metal wires. During the experiments, the gas flow rate and bubble size were varied. Additionally, a dataset for foam flow past a single wire is included for reference.


The folder includes initial data for the manuscript "Generating structured foam via flowing through a wire array".

Folder includes:

01_scripts scripts used for the data processing
02_rawdata Initial neutron imaging data (.tif images)
03_evaluation folder with MATLAB scripts used for data analysis

LABBOOK Experimental labbook explaining the experimental sequence.
Protocol The Neutron imaging protocol with the data of neutron source and image resolution

The data processing is shown for the O1 bubble generator. It includes:
1. MASK_... script used to define the cell walls and determine the mask, used further for the liquid fraction calculation.
2. N13_INIT... scritps to define normalised image, which further used to determine liquid fraction distribution
3. POST_BOT... scripts used to postprocess the data: define Liquid fraction distribution and DFT of those distributions.

Note: 

1. The data were analysed at two positions: bottom (0) and top (100), meaining at the wire grid and 100 mm downstream the grid. To this end, mask should be calculated also for the top part of the nozzle, if needed, as shown in the presented examples.

2. The data for the empty cell were calculated for the foam flow through the cell with a single thin wire. Teh data were extracted
in the ROI before the wire (run 553-557).

3. Data processing was performed as suggested in https://doi.org/10.1371/journal.pone.0210300

Keywords: Foam; Neutron imaging; Radiography

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Permalink: https://www.hzdr.de/publications/Publ-41043


The Data Management Evolution in the Photon and Neutron Community (PaNOSC)

Knodel, O.

Abstract

The presentation refers to the advances in research data management developed for the photon and neutron communities (PaN) in the context of the two EU projects PaNOSC and ExPaNDS. Both projects played a crucial role in advancing open science within the European research landscape.

Keywords: PaNOSC; ExPANDS; PaN; Photon and Neutron; Data Management

  • Open Access Logo Invited lecture (Conferences)
    Love Data Week at OSL, 14.02.2025, Open Science Lab, SLUB Dresden, Germany
    DOI: 10.5281/zenodo.14887431

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Permalink: https://www.hzdr.de/publications/Publ-41041


Data and code publication: Exact expression for the propagating front velocity in nonlinear discrete systems under nonreciprocal coupling

Pinto Ramos, D. I.

Abstract

Data used to generate the figures of the paper.

.- Data_Fronts_1

.- FK_run_1

.- LC_run_1

Code for the numerical simulations that produce the data analyzed.

.- Integrator.py (module containing functions)

.- Integra_General_paralelo_1.py (runnable script to generate data Figs. 2-4)

.- Integra_FK_paralelo_1.py (runnable script to generate data Fig. 5)

.- Integra_LC_paralelo_1.py (runnable script to generate data Fig. 6)

Code for the data analysis and creation of the figures.

.- velocities_General_1.py (runnable script to generate Figs. 2-4 from data)

.- velocities_FK_1.py (runnable script to generate Fig. 5 from data)

.- velocities_LC_1.py (runnable script to generate Fig. 6 from data)

Related publications

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Permalink: https://www.hzdr.de/publications/Publ-41035


Accessing neodymium in end-of-life magnet materials using innovative leaching and selective solvent extraction

Kelottijärvi, L.; Kelly, N.; Ebert, D.; Väisänen, A. O.; Patil, A. B.

Abstract

Rare earth elements (REEs) have become necessary in a wide range of high-technology applications due to their unique magnetic, electronic and optical properties. The materials are used in consumer electronics, and they play a big role in the renewable energy technologies. Although REEs are relatively abundant in the Earth’s crust, low concentrations of single elements in minerals makes economically viable extraction challenging. With the growth of green technologies, global demand for REEs can be expected to rise significantly, increasing the need for efficient recycling and recovery of these materials.
NdFeB permanent magnets contain notable amount of REEs like neodymium, praseodymium, dysprosium and gadolinium, therefore making end-of-life magnets a valuable waste stream. The development of effective recycling processes optimizes the return of valuable metals, minimizes the need for primary mining of REE and reduces Europe's dependence on imports of critical raw materials. In this study, we investigate the leaching of waste magnet powders with mineral and organic acids in dependence on typical parameters like leaching time and acid concentration. Since the pregnant leaching solution (PLS) contains a significant amount of Fe(III), an innovative solvent extraction route for the selective separation of Fe(III) is developed. It is important to mention that, Fe(III) removal is universal and critical issue in primary and secondary processing of rare earth metals.
Optimization of the relevant process parameters contact time, pH, A/O ratio and anion system for single element and mixed solutions of Nd(III) and Fe(III) in the extraction system NdX3–FeX3–acid/amine–kerosene is carried out. Extraction yields of 80–95 % for Fe(III) and 10–30 % for Nd(III) in pHeq. of 1.8 indicate a possible separation of Fe(III) from a PLS. As a result of further investigations such like the development of extraction isotherms, process conditions for continuous experiments with laboratory mixer-settler system are set. In addition, the method is tested for solution containing organic acid.

Involved research facilities

  • Metallurgy Technical Centre
  • Lecture (Conference)
    Jahrestreffen der DECHEMA-Fachgruppe Extraktion, 19.-20.02.2025, Aachen, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-41032


Unraveling warm dense matter: from ab initio simulations to X-ray Thomson scattering (XRTS)

Dornheim, T.

Abstract

Warm dense matter (WDM) is an extreme state that abounds in a host of astrophysical objects such
as giant planet interiors, brown dwarfs, and the outer layer of neutron stars. On Earth, WDM plays
an important role for technological applications such as material science, synthesis and discovery. A
particularly important application is given by inertial confinement fusion, where both the fuel
capsule and the ablator have to traverse the WDM regime in a controlled way to reach ignition.
From a physical perspective, WDM is characterized by the intriguing though highly nontrivial
interplay of effects such as Coulomb coupling, strong thermal excitations, quantum degeneracy and
partial ionization, making its rigorous theoretical description notoriously difficult [1]. A second
challenging aspect of studying WDM is the reliable diagnostics of corresponding experiments.
Here, X-ray Thomson scattering (XRTS) has emerged as a widely used tool that is, in principle,
capable of giving one microscopic insights into the probed sample [2]. In practice, however, the
interpretation of XRTS measurements requires an accurate theoretical description of its electronic
properties, which were usually treated based on a number of de-facto uncontrolled model
assumptions such as the decomposition into effectively bound and free electrons within chemical
models.
Here, I give an overview of a number of recent developments that open up new avenues for the
future study of warm dense matter without previous models and approximations. First, I will show
how we can extract a wealth of information such as the temperature [3] or the absolute intensity [4]
directly from the XRTS measurement by switching to the so-called imaginary-time domain---a well
known concept that naturally emerges in Feynman’s path integral formulation of statistical
mechanics and that involves a simple Laplace transform of the experimental signal. Second, I will
show new ab initio path integral Monte Carlo (PIMC) simulation capabilities [5] that allow us to
simulate light elements without any empirical input such as the usual exchange—correlation
functional in DFT or the nodal structure in restricted PIMC. Taken together, these advances allow
for a true first-principles interpretation of the measured XRTS intensity. As a practical example, we
re-examine an XRTS measurement on warm dense beryllium that was collected at the National
Ignition Facility (NIF) in California. Interestingly, we find that using either PIMC or DFT [6]
simulations leads to a substantially reduced mass density compared to the much simpler chemical
models used in the original work [7], which has important implications for the interpretation of
future XRTS experiments, and which calls into question the accuracy of radiation hydrodynamics
models in the WDM regime.
The talk is concluded by outlining remaining limitations and ongoing efforts to extend current
capabilities [8].
[1] T. Dornheim et al., Physics of Plasmas 30, 032705 (2023)
[2] S. Glenzer and R. Redmer, Reviews of Modern Physics 81, 1625 (2009)
[3] T. Dornheim et al., Nature Communications 13, 7911 (2022)
[4] T. Dornheim et al., Scientific Reports 14, 14377 (2024)
[5] T. Dornheim et al., arXiv:2402.19113 (submitted)
[6] T. Dornheim et al., arXiv.2409.08591 (submitted)
[7] T. Döppner et al., Nature 618, 270-275 (2023)
[8] Th. Gawne et al., Physical Review B 109, L241112 (2024)

  • Lecture (others)
    Physics seminar at LuLi / Ecole Polytechnique, 24.02.2025, Palaiseau, France

Permalink: https://www.hzdr.de/publications/Publ-41029


From ab initio simulations to x-ray Thomson scattering (XRTS)

Dornheim, T.; Kraus, D.; Preston, T.; Boehme, M.; Doeppner, T.; Moldabekov, Z.; Baczewski, A.; Fletcher, L.; Vorberger, J.

Abstract

We summarize a number of recent developments that allow for the model-free interpretation of x-ray Thomson scattering (XRTS) measurements taken on warm dense matter combined with state-of-the-art ab initio path integral Monte Carlo (PIMC) simulations. As a practical example, we consider a an XRTS dataset taken at the National Ignition Facility (NIF) on strongly compressed beryllium. Interestingly, our new approach gives us a substantially lower density compared to previously used chemical models, which has potentially important implications for the integrated radiation hydrodynamics modelling of inertial fusion energy applications.

  • Poster
    Nif Usergroup Meeting (NUG), 11.-13.02.2025, Livermore, USA

Permalink: https://www.hzdr.de/publications/Publ-41028


Targeted bismuth-based materials for cancer

Batool, A.; Kopp, I.; Kubeil, M.; Bachmann, M.; Andrews, P.; Stephan, H.

Abstract

The use of bismuth and its compounds in biomedicine has developed rapidly in recent years. Due to their unique properties, there are great opportunities for the development of new non-invasive strategies for the early diagnosis and effective treatment of cancers. This perspective highlights key fabrication methods to generate well-defined and clinically relevant bismuth materials of varying characteristics. On the one hand, this opens up a wide range of possibilities for unimodal and multimodal imaging. On the other hand, for effective treatment strategies, which are increasingly based on combinatorial therapies, are given a great deal of attention. One of the biggest challenges remains the selective tumour targeting, whether active or passive. Here we present an overview on new developments of bismuth based materials moving forward from a simple enrichment at the tumour site via uptake by the mononuclear phagocytic system (MPS) to a more active tumour specific targeting via covalent modification with tumour-seeking molecules based on either small or antibody-derived molecules.

Permalink: https://www.hzdr.de/publications/Publ-41023


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