Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

The cementitious properties of natural Mg-rich olivine when reacted with a phosphoric acid solution are investigated, as a function of acid concentration and liquid/solid mass ratio. The obtained cements are composed of residual olivine crystals and amorphous silica nanoparticles dispersed in a dense and compact newberyite (MgHPO4∙3H2O) matrix. The latter was mostly formed by packed micrometric tabular crystals, although evidence of the presence of a fraction of amorphous MgHPO4 was also found. Water content in the raw mix was observed to play a pivotal role on the reaction pathway, either promoting porosity or hindering the crystallization of the products. Up to 57 % of olivine reactivity, whose dissolution was promoted by the curing temperature (60 °C) and low pH, was achieved. All in all, these results indicate that the industrial mineral olivine may serve a viable source of Mg for the production of phosphate cements.

This study explores the bulk crystal growth, structural characterization, and physical property measurements of the cubic double perovskite Ba₂CoWO₆ (BCWO). In BCWO, Co²⁺ ions form a face-centred cubic lattice with non-distorted cobalt octahedra. The compound exhibits long-range antiferromagnetic order below T_N = 14 K. Magnetization data indicated a slight anisotropy along with a spin-flop transition at 10 kOe, a saturation field of 310 kOe and an ordered moment of 2.17 μ_B at T = 1.6 K. Heat capacity measurements indicate an effective j = 1/2 ground state configuration, resulting from the combined effects of the crystal electric field and spin-orbit interaction. Surface photovoltage analysis reveals two optical gaps in the UV–Visible region, suggesting potential applications in photocatalysis and photovoltaics. The magnetic and optical properties highlight the significant role of orbital contributions within BCWO, indicating various other potential applications.

The first-order transition line in the H-T phase diagram of itinerant electron metamagnets terminates at the critical end point—analogous to the critical point on the gas-liquid condensation line in the p-T phase diagram. To unravel the impact of critical magnetic fluctuations on the crystal lattice of a metamagnet at the critical end point, we performed an ultrasonic study of the itinerant electron metamagnet UTe₂ across varying temperatures and magnetic fields. At temperatures exceeding 9 K, a distinct V-shaped anomaly emerges, precisely centered at the critical field of the metamagnetic transition in the isothermal field dependence of elastic constants. This anomaly arises from lattice instability, triggered by critical magnetic fluctuations via strong magnetoelastic interactions. Remarkably, this effect is maximized precisely at the critical-end-point temperature. Comparative measurements of another itinerant metamagnet, UCoAl, reveal intriguing commonalities. Despite significant differences in the paramagnetic ground state, lattice symmetry, and the expected metamagnetic transition process between UTe₂ and UCoAl, both exhibit similar anomalies in elastic properties near the critical end point.

Magnetic refrigeration, which utilizes the magnetocaloric effect, can provide a viable alternative to the ubiquitous vapor compression or Joule-Thompson expansion methods of refrigeration. For applications such as hydrogen gas liquefaction, the development of magnetocaloric materials that perform well in moderate magnetic fields without using rare-earth elements is highly desirable. Here we present a thorough investigation of the structural and magnetocaloric properties of a novel layered organic-inorganic hybrid coordination polymer Co₄(OH)₆(SO₄)₂[enH₂] (enH₂ = ethylenediammonium). Heat capacity, magnetometry and direct adiabatic temperature change measurements using pulsed magnetic fields reveal a field-dependent ferromagnetic second-order phase transition at 10 K < T_C < 15 K. Near the hydrogen liquefaction temperature and in a magnetic field change of 1 T, a large maximum value of the magnetic entropy change, ΔS^Pk _M = − 6.31 J kg⁻¹ K⁻¹, and an adiabatic temperature change, ΔT_ad = 1.98K, areobserved. These values are exceptional for rare-earth-free materials and competitive with many rare-earth-containing alloys that have been proposed for magnetic cooling around the hydrogen liquefaction range.

The interface of common III-V semiconductors InAs and GaSb can be utilized to realize a two-dimensional (2D) topological insulator state. The 2D electronic gas at this interface can yield Hall quantization from coexisting electrons and holes. This anomaly is a determining factor in the fundamental origin of the topological state in InAs/GaSb. Here, the coexistence of electrons and holes in InAs/GaSb is tied to the chemical sharpness of the interface. Magnetotransport, in samples of Mn-doped InAs/GaSb cleaved from wafers grown at a spatially inhomogeneous substrate temperature, is studied. It is reported that the observation of quantum oscillations and a quantized Hall effect whose behavior, exhibiting coexisting electrons and holes, is tuned by this spatial nonuniformity. Through transmission electron microscopy measurements, it is additionally found that samples that host this co-existence exhibit a chemical intermixing between group III and group V atoms that extends over a larger thickness about the interface. The issue of intermixing at the interface is systematically overlooked in electronic transport studies of topological InAs/GaSb. These findings address this gap in knowledge and shed important light on the origin of the anomalous behavior of quantum oscillations seen in this 2D topological insulator.

Bimetallic nanostructures are promising candidates for the development of enzyme-mimics, yet the deciphering of the structural impact on their catalytic properties poses significant challenges. By leveraging the structural versatility of nanocrystal aerogels, this study reports a precise control of Au-Pt bimetallic structures in three representative structural configurations, including segregated, alloy, and core-shell structures. Benefiting from a synergistic effect, these bimetallic aerogels demonstrate improved peroxidase- and glucose oxidase-like catalytic performances compared to their monometallic counterparts, unleashing tremendous potential in catalyzing the glucose cascade reaction. Notably, the segregated Au-Pt aerogel shows optimal catalytic activity, which is 2.80 and 3.35 times higher than that of the alloy and core-shell variants, respectively. This enhanced activity is attributed to the high-density Au-Pt interface boundaries within the segregated structure, which foster greater substrate affinity and superior catalytic efficiency. This work not only sheds light on the structure-property relationship of bimetallic catalysts but also broadens the application scope of aerogels in biosensing and biological detections.

Polaritons, i.e., hybrid quasi-particles of light and matter resonances, have been extensively investigated due to their potential to enhance light–matter interactions. Although polaritonic applications thrive in the mid-infrared range, their extension to the terahertz (THz) range remains limited. Here, we present paratellurite (α-TeO2) nanowires, a versatile material acting as a platform for different types of phonon polaritons. Utilizing synchrotron infrared nanospectroscopy from 10 to 24 THz, we uncover the polaritonic properties of α-TeO2 nanowires, showcasing their dual functionality as both a Fabry–Pérot cavity and a waveguide for surface phonon polaritons. Furthermore, near-field measurements with a free-electron laser as a THz source reveal a localized optical contrast down to 5.5 THz, an indication of hyperbolic bands. Our findings complement the repertoire of polaritonic materials, with significant implications for advancing THz technologies.

External control of optical excitations is key for manipulating light–matter coupling and is highly desirable for photonic technologies. Excitons in monolayer semiconductors emerged as a unique nanoscale platform in this context, offering strong light–matter coupling, spin–valley locking and exceptional tunability. Crucially, they allow electrical switching of their
optical response due to efficient interactions of excitonic emitters with free charge carriers, forming new quasiparticles known as trions and Fermi polarons. However, there are major limitations to how fast the light emission of these states can be tuned, restricting the majority of applications to an essentially static regime. Here we demonstrate switching of excitonic light
emitters in monolayer semiconductors on ultrafast picosecond time scales by applying short pulses in the terahertz spectral range following optical injection. The process is based on a rapid conversion of trions to excitons by absorption of terahertz photons inducing photo detachment. Monitoring time-resolved emission dynamics in optical-pump/terahertz-push
experiments, we achieve the required resonance conditions as well as demonstrate tunability of the process with delay time and terahertz pulse power. Our results introduce a versatile experimental tool for fundamental research of light-emitting excitations of composite Bose–Fermi mixtures and open up pathways towards technological developments of new types of nanophotonic device based on atomically thin materials.

Curvilinear magnetism is a framework, which helps understanding the impact of geometric curvature on complex magnetic responses of curved 1D wires and 2D shells [1-3]. This approach provides means to modify conventional or to launch novel functionalities by tailoring curvature and 3D shape of magnetic thin films and nanowires [3]. In this talk, we will address fundamentals of curvature-induced effects in magnetism and review the envisioned application scenarios. In particular, we will demonstrate that curvature allows tailoring fundamental anisotropic and chiral magnetic interactions and enables fundamentally new nonlocal chiral symmetry breaking effect [4]. The topology of the geometry of 3D shaped magnetic objects allows stabilizing multiple solitons within a confined nanoarchitecture [5]. Those are relevant for numerous research and technology fields ranging from non-conventional computing and spin-wave splitters for low-energy magnonics. The application potential of geometrically curved magnetic architectures is being explored as mechanically reshapeable magnetic field sensors for automotive applications, spin-wave filters, high-speed racetrack memory devices, magnetic soft robots [6] as well as on-skin interactive electronics relying on thin films [7-9] as well as printed magnetic composites [10,11] with appealing self-healing performance [12]. This opens perspectives for magnetoelectronics in smart wearables, interactive printed electronics and motivates further explorations towards the realization of eco-sustainable magnetic field sensing relying on biocompatible and biodegradable materials [13-15].

[1] P. Gentile et al., Electronic materials with nanoscale curved geometries. Nature Electronics (Review) 5, 551 (2022).
[2] P. Makushko et al., A tunable room-temperature nonlinear Hall effect in elemental bismuth thin films. Nature Electronics 7, 207 (2024).
[3] D. Makarov et al., New Dimension in Magnetism and Superconductivity: 3D and Curvilinear Nanoarchitectures. Advanced Materials (Review) 34, 2101758 (2022).
[4] O. M. Volkov et al., Chirality coupling in topological magnetic textures with multiple magnetochiral parameters. Nature Communications 14, 1491 (2023).
[5] O. Volkov et al., Three-dimensional magnetic nanotextures with high-order vorticity in soft magnetic wireframes. Nature Communications 15, 2193 (2024).
[6] M. Ha et al., Reconfigurable Magnetic Origami Actuators with On-Board Sensing for Guided Assembly. Advanced Materials 33, 2008751 (2021).
[7] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Advanced Functional Materials (Review) 31, 2007788 (2021).
[8] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[9] G. S. Canon Bermudez et al., Electronic-skin compasses for geomagnetic field driven artificial magnetoception and interactive electronics. Nature Electronics 1, 589 (2018).
[10] M. Ha et al., Printable and Stretchable Giant Magnetoresistive Sensors for Highly Compliant and Skin-Conformal Electronics. Advanced Materials 33, 2005521 (2021).
[11] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Advanced Materials Technologies 7, 2200227 (2022).
[12] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).
[13] X. Wang et al., Printed magnetoresistive sensors for recyclable magnetoelectronics. J. Mater. Chem. A 12, 24906 (2024).
[14] E. S. Oliveros Mata et al., Magnetically aware actuating composites: Sensing features as inspiration for the next step in advanced magnetic soft robotics. Phys. Rev. Appl. (Review) 20, 060501 (2023).
[15] L. Guo et al., Printable magnetoresistive sensors: A crucial step toward unconventional magnetoelectronics. Chinese Journal of Structural Chemistry (Review) 100428 (2024).

Presentation at "International Workshop on Baryon and Lepton Number Violation", Karlsruhe (Germany), Ovtober 8-11, 2024

In this presentation, I will discuss our recent advancements in utilizing machine learning to significantly enhance the efficiency of electronic structure calculations [1]. Specifically, I will focus on our efforts to accelerate Kohn-Sham density functional theory calculations by incorporating deep neural networks within the Materials Learning Algorithms framework [2,3]. Our results demonstrate substantial gains in calculation speed for metals across their melting point. Additionally, our implementation of automated machine learning has resulted in significant savings in computational resources when identifying optimal neural network architectures, laying the foundation for large-scale investigations [4]. Furthermore, I will present our most recent breakthrough, which enables neural-network-driven electronic structure calculations for systems containing over 100,000 atoms [5]. This achievement opens up new avenues for studying complex materials systems that were previously computationally intractable.

[1] L. Fiedler, K. Shah, M. Bussmann, A. Cangi, Phys. Rev. Materials, 6, 040301 (2022)
[2] A. Cangi, J. A. Ellis, L. Fiedler, D. Kotik, N. A. Modine, V. Oles, G. A. Popoola, S. Rajamanickam, S. Schmerler, J. A. Stephens, A. P. Thompson, Phys. Rev. B 104, 035120 (2021).
[3] J. Ellis, L. Fiedler, G. Popoola, N. Modine, J. Stephens, A. Thompson, A. Cangi, S. Rajamanickam, Phys. Rev. B, 104, 035120 (2021)
[4] L. Fiedler, N. Hoffmann, P. Mohammed, G. Popoola, T. Yovell, V. Oles, J. Austin Ellis, S. Rajamanickam, A. Cangi, Mach. Learn.: Sci. Technol., 3, 045008 (2022)
[5] L. Fiedler, N. Modine, S. Schmerler, D. Vogel, G. Popoola, A. Thompson, S. Rajamanickam, A. Cangi, npj. Comput. Mater., 9, 115 (2023)

The transition to renewable energies and electric vehicles has triggered an unprecedented demand for metals.
Sustainable development of these technologies relies on effectively managing the lifecycle of critical raw materials, including their responsible sourcing, efficient use, and recycling. Metal recycling from electronic waste
(e-waste) is of paramount importance owing to ore-exceeding amounts of critical elements and high toxicity of
heavy metals and organic pollutants in e-waste to the natural ecosystem and human body. Heterotrophic microbes secrete numerous metal-binding biomolecules such as organic acids, amino acids, cyanide, siderophores,
peptides, and biosurfactants which can be utilized for eco-friendly and profitable metal recycling. In this review
paper, we presented a critical review of heterotrophic organisms in biomining, and current barriers hampering
the industrial application of organic acid bioleaching and biocyanide leaching. We also discussed how these
challenges can be surmounted with simple methods (e.g., culture media optimization, separation of microbial
growth and metal extraction process) and state-of-the-art biological approaches (e.g., artificial microbial community, synthetic biology, metabolic engineering, advanced fermentation strategies, and biofilm engineering).
Lastly, we showcased emerging technologies (e.g., artificially synthesized peptides, siderophores, and biosurfactants) derived from heterotrophs with the potential for inexpensive, low-impact, selective and advanced
metal recovery from bioleaching solutions

This publication presents a study on the mineral chemistry and luminescence properties of quartz samples from pegmatites of the Tørdal region in Norway. A total of 12 samples were analyzed using Secondary Ion Mass Spectrometry (SIMS), Electron Paramagnetic Resonance Spectroscopy (EPR), and Cathodoluminescence (CL) to gain insights into their trace element concentration and distribution as well as their luminescence behavior. The samples are characterized by different Cl emissions at 450 nm, 500 nm 650 nm and an additional shoulder at 390 nm, which is only partially visible due to the absorption of the glass optics. Of these luminescence bands, the 500 nm band is the most dominant in most samples and it is characterized by an initial blue-green luminescence, which is not stable under electron irradiation. Moreover, it is characterized by a heterogeneous distribution within the samples. This luminescence can be mostly assigned to [AlO4/M+]0 defects, with charge compensation mostly achieved by Li+. Analyses by EPR spectroscopy prove the dominance of structurally bound Al, Li, and Ti ions in the investigated samples. Further analyses using SIMS mapping demonstrate that Na and K are mainly bound to micro fractures or inclusions, suggesting a limited role in the compensation of the luminescence centers. Additionally, the SIMS mappings show that some samples contain Al-rich clusters of 10 to 20 μm in diameter, whereas other trace elements are characterized by a homogeneous distribution. These clusters correspond to bright luminescence areas in size and shape and could potentially indicate H+ compensated [AlO4/M+]0 defects.

A highly efficient reconstruction method has been developed for the direct computation of Hamiltonian matrices in the atomic orbital basis from density functional theory calculations originally performed in the plane wave basis. This enables machine learning calculations of electronic structures on a large scale, which are otherwise not feasible with standard methods, and thus fills a methodological gap in terms of accessible length scales.

In this manuscript we evaluate the X-ray structure of five new pertechnetate derivatives of general formula [M(H₂O)₄(TcO₄)₂], M=Mg, Co, Ni, Cu, Zn (compounds 1–5) and one perrhenate compound Zn(H₂O)₄(ReO₄)₂ (6). In these complexes the metal center exhibits an octahedral coordination with the pertechnetate units as axial ligands. All compounds exhibit the formation of directional Tc⋅⋅⋅O Matere bonds (MaBs) that propagate the [M(H₂O)₄(TcO₄)₂], into 1D supramolecular polymers in the solid state. Such 1D polymers are linked, generating 2D layers, by combining additional MaBs and hydrogen bonds (HBs). Such concurrent motifs have been analyzed theoretically, suggesting the noncovalent σ-hole nature of the MaBs. The interaction energies range from weak (~ −2 kcal/mol) for the MaBs to strong (~ −30 kcal/mol) for the MaB+HB assemblies, where HB dominates. In case of M=Zn, the corresponding perrhenate Zn(H₂O)₄(ReO₄)₂ complex, has been also synthesized for comparison purposes, resulting in the formation of an isostructural X-ray structure, corroborating the structure-directing role of Matere bonds.

This study aimed to find a rapid extraction system for the preparation of a Seaborgium (Sg) aqueous chemistry experiment in the future. A new approach for extraction of ¹⁸¹W tracer as a lighter homolog of (Sg) by ionic liquids is explored. A natural tantalum target was activated by a beam of 9 MeV proton at Cologne University to produce carrier-free ¹⁸¹W. The preliminary batch extraction experiments of the carrier-free ¹⁸¹W from HCl and H₂SO₄ solutions have been evaluated. Different batch extraction parameters such as feed acidity, diluent type, ionic strength (KCl feed) and reducing agent as a function of time were explored. The obtained results demonstrated that the highest distribution of carrier-free ¹⁸¹W from 0.001 M acidic solutions using the used ionic liquid is observed. A significant rapid kinetic for the extraction of trace-scale using the used ionic liquid is achieved within 5 sec. The preliminary results are necessary to design the upcoming aqueous experiments of Sg. The next goal will be on-line experiments with the centrifuge system SISAK to develop the aqueous chemistry extraction of Sg using the most promising and adequate experimental setup.

The number of crystal structures of pertechnetates derived from aqueous solutions has been expanded from seven to over 30. We report the conversion of NH₄TcO₄ to aqueous HTcO₄ via acidic cation exchange. This is followed by the synthesis and structural elucidation of pertechnetate salts of alkaline earth (AE), transition metal I and lanthanoids (Ln) elements. Various degrees of hydration and coordination are discussed. Where possible, a comparison with the perrhenate homologues is made. The described syntheses and materials may be used as novel starting materials for extended technetium research.

Exotic band features, such as Dirac cones and flat bands, arise directly from the lattice symmetry of materials. The Lieb lattice is one of the most intriguing topologies, because it possesses both Dirac cones and flat bands which intersect at the Fermi level. However, the synthesis of Lieb lattice materials remains a challenging task. Here, we explore two-dimensional polymers (2DPs) derived from zinc-phthalocyanine (ZnPc) building blocks with a square lattice (sql) as potential electronic Lieb lattice materials. By systematically varying the linker length (ZnPc-xP), we found that some ZnPc-xP exhibit a characteristic Lieb lattice band structure. Interestingly though, fes bands are also observed in ZnPc-xP. The coexistence of fes and Lieb in sql 2DPs challenges the conventional perception of the structure–electronic structure relationship. In addition, we show that manipulation of the Fermi level, achieved by electron removal or atom substitution, effectively preserves the unique characteristics of Lieb bands. The Lieb Dirac bands of ZnPc-4P shows a non-zero Chern number. Our discoveries provide a fresh perspective on 2DPs and redefine the search for Lieb lattice materials into a well-defined chemical synthesis task.

In this study, the dissolution of a single oxygen bubble on a solid surface, here Titanium alloy Ti64, in ultrapure water with different oxygen undersaturation levels is investigated. For that purpose, a combination of shadowgraph technique and planar laser-induced fluorescence is used to measure simultaneously the changes in bubble geometry and in the dissolved oxygen concentration around the bubble. Two different wettabilities of the Ti64 surface are adjusted by using plasma-enhanced chemical vapor deposition. The dissolution process on the solid surface involves two distinct phases, namely bouncing of the oxygen bubble at the Ti64 surface and the subsequent dissolution of the bubble, primarily by diffusion. By investigating the features of oxygen bubbles bouncing, it was found that the boundary layer of dissolved oxygen surrounding the bubble surface is redistributed by the vortices emerging during bouncing. This establishes the initial conditions for the subsequent second dissolution phase of the oxygen bubbles on the Ti64 surfaces. In this phase, the mass transfer of O2 proceeds non-homogeneously across the bubble surface, leading to an oxygen accumulation close to the Ti64 surface. We further show that the main factor influencing the differences in the dynamics of O2 bubble dissolution is the variation in the surface area of the bubbles available for mass transfer, which is determined by the substrate wettability. As a result, dissolution proceeds faster at the hydrophilic Ti64 surface due to the smaller contact angle, which provokes a larger surface area.

At the electron accelerator for beams with high brilliance and low emittance (ELBE), the second version of a superconducting radio-frequency (SRF) photoinjector was brought into operation in 2014. After a period of commissioning, a gradual transfer to routine operation took place in 2017, so that now more than 1800h of user beam are generated every year. In addition to this routine operation with a few tens of microamperes, another important goal, the generation of an average current of 1 mA, which is high for electron linear accelerators, could now be demonstrated with our SRF gun. At the same time, this beam was already accelerated to almost 30 MeV by the ELBE LINAC and irradiated in one of the IR-FELs. This is particularly important with regard to the successor of the ELBE accelerator called DALI, which will be also fed by an SRF gun with a high average current. The contribution presents the most important steps for achieving the full beam current and summarizes related measurement results and findings. No fundamental difficulties were identified.

Bilayer graphene (BLG) has recently been used as a tool to stabilize the encapsulated single sheets of various layered materials and tune their properties. It was also discovered that the protecting action of graphene sheets makes it possible to synthesize completely new two-dimensional materials (2DMs) inside BLG by intercalating
various atoms and molecules. In comparison to the bulk graphite, BLG allows for easier intercalation and much larger increase in the inter-layer separation of the sheets. Moreover, it enables studying the atomic structure of the intercalated 2DM using high-resolution transmission electron microscopy. In this review, we summarize the recent
progress in this area, with a special focus on new materials created inside BLG. We compare the experimental findings with the theoretical predictions, pay special attention to the discrepancies and outline the challenges in the field. Finally, we discuss unique opportunities offered by the intercalation into 2DMs beyond graphene and their
heterostructures.

Uranium (U) mining has left a legacy of environmental contamination in the Federal States of Saxony and Thuringia (Germany). High concentrations of U and other heavy metals pose a potential threat to both the environment and human health, through contamination of soil and water. Additionally, it is well documented that other human activities, such as agronomic practices and military conflicts, have contributed to increasing the concentration of these contaminants. However, U has become one of the world's most important elements in the last 60 years due to its potential use in nuclear energy production. Therefore, it is essential to develop environmental rehabilitation programs in affected areas, along with adopting waste management practices that promote sustainability, including the possibility of recovering U from waste for reuse within the concept of circular economy.

Traditionally, physicochemical based conventional technologies have been used to remediate environments contaminated with U. However, these approaches tend to be costly, complex to apply, and ineffective for low concentrations of U. Hence, a promising alternative, less expensive, easy to implement, and effective for low U concentrations is bioremediation, based on the interaction mechanisms of biological systems with U. Based on extensive available literature, the main suggested strategies for U bioremediation include two approaches: biomineralization of U(VI) phosphates under oxic conditions and enzymatic reduction under anoxic conditions from soluble, highly mobile, and bioavailable U(VI) to insoluble, less mobile, and thus less bioavailable U(IV).

The aim of this PhD thesis was to characterize, through a multidisciplinary approach, two former German mine waters contaminated with U, Schlema-Alberoda and Pöhla (Wismut GmbH), in order to design a future U bioremediation strategy based on biostimulation of the native U-reducing microbial community.

The bioremediation of contaminated waters with low U concentrations shows a significant challenge, which can be addressed by stimulating U-reducing bacterial activity, as described in this PhD thesis. Moreover, this study not only provides new insights on the reduction of U(VI) to U(IV) but also emphasizes that the resulting product, U(V), is more stable than uraninite, thus increasing the potential of this strategy, considering the risk of U reoxidation.

At the technical colloquium on September 5th, Antonio Newman will present the findings of his PhD thesis. This project was developed in collaboration between the University of Granada (Spain) and the Helmholtz-Zentrum Dresden-Rossendorf (Germany), in collaboration with Wismut GmbH.
The project first geochemically characterized the mine water from Schlema-Alberoda and Pöhla using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and High Pressure Ion Chromatography (HPIC). Simultaneously, it analysed the microbial community through sequencing of bacterial 16S rRNA and fungal ITS genes. Additionally, this work explored key metabolic pathways involved in the biogeochemical cycles of sulphur, nitrogen, and carbon using metatranscriptomic analysis to understand the differences in U concentrations between the two mine waters. The study also involved isolating, identifying, and biochemically characterizing fungi from these waters, searching for strains with U immobilization potential. Finally, a complementary bioremediation strategy was designed and optimized to reduce U in the Schlema-Alberoda mine water, using the native bacterial community and glycerol as an electron donor, while characterizing the reduced U products with spectroscopic (e.g., High-Energy-Resolution Fluorescence Detected X-Ray Absorption Near Edge Structure (HERFD-XANES) and (Extended X-Ray Absorption Fine Structure (EXAFS)) and microscopic techniques (e.g., HRTEM).
The most notable findings of this PhD thesis include the effectiveness of using glycerol as an electron donor to stimulate the native microbial community involved in reducing soluble U in the Schlema-Alberoda mine water as a bioremediation strategy. Additionally, the study reports not only the reduction of U(IV) but also surprisingly high proportions of biogenic stable U(V), which had not been previously documented in the literature.

As the physicochemical properties of ultrafine bubble systems are governed by their size, it is crucial to determine the size and distribution of such bubble systems. At present, the size or size distribution of nanometer-sized bubbles in suspension is often measured by either dynamic light scattering or the nanoparticle tracking analysis. Both techniques determine the bubble size via the Einstein–Stokes equation based on the theory of the Brownian motion. However, it is not yet clear to which extent the Einstein–Stokes equation is applicable for such ultrafine bubbles. In this work, using atomic molecular dynamics simulation, we evaluate the applicability of the Einstein–Stokes equation for gas nanobubbles with a diameter less than 10 nm, and for a comparative analysis, both vacuum nanobubbles and copper nanoparticles are also considered. The simulation results demonstrate that the diffusion coefficient for rigid nanoparticles in water is found to be highly consistent with the Einstein–Stokes equation, with slight deviation only found for nanoparticle with a radius less than 1 nm. For nanobubbles, including both methane and vacuum nanobubbles, however, large deviation from the Einstein–Stokes equation is found for the bubble radius larger than 3 nm. The deviation is attributed to the deformability of large nanobubbles that leads to a cushioning effect for collision-induced bubble diffusion.

We provide an extended lattice study of the SU(2) gauge theory coupled to one Dirac fermion flavour (Nf=1Nf​=1) transforming in the adjoint representation as the continuum limit is approached. This investigation is supplemented by numerical results obtained for the SU(2) gauge theory with two Dirac fermion flavours (Nf=2Nf​=2) transforming in the adjoint representation, for which we perform numerical investigations at a single lattice spacing value, which is analysed together with earlier calculations. The purpose of our study is to advance the characterisation of the infrared properties of both theories, which previous investigations have concluded to be in the conformal window. For both, we determine the mass spectrum and the anomalous dimension of the fermion condensate using finite-size hyperscaling of the spectrum, mode number analysis of the Dirac operator (for which we improve on our previous proposal) and the ratio of masses of the lightest spin-2 particle over the lightest scalar. All methods provide a consistent picture, with the anomalous dimension of the condensate γ∗γ∗​ decreasing significantly as one approaches the continuum limit for the Nf=1Nf​=1 theory towards a value consistent with γ∗=0.174(6)γ∗​=0.174(6), while for Nf=2Nf​=2 the anomalous dimension decreases more slowly with ββ. A chiral perturbation theory analysis show that the infrared behaviour of both theories is incompatible with the breaking of chiral symmetry.

The Dresden laser acceleration source (DRACO) is a state-of-the-art high-power ultra-short pulse laser system[1,2],
that uses an Amplitude Technologies Pulsar architecture to form main and diagnostics beams at different focal lengths and target density conditions.
The setup can deliver from 6J to 45J of pulse energy at a typical pulse duration of 30fs and a typical frequency of 1Hz.
During the diagnostic phase, the beam characteristics are recorded in the form of images and several instrument parameters,
that shape the beam to desired characteristics.

In this talk, we present our approach of implementing FAIR principles to DRACO
operations and monitoring using our in-house guidance system HELIPORT[3],
with the goal of making them reusable irrespective of the downstream experiment.
We employ FAIR workflows[4] to post-process data collected by DRACO's built-in data
acquisition system and enrich it with metadata for subsequent utilization in
machine-learning and optimization algorithms for accurate control of the beam characteristics.
The intergration of DRACO and HELIPORT demonstrates the first step towards establishing
a digital twin for the laser source facility at HZDR.

[1] First results with the novel Petawatt laser acceleration facility in Dresden, U. Schramm et al, J. Phys. Conf. Ser. 874 012028 (2017)
[2] High dynamic, high resolution and wide range single shot temporal pulse contrast measurement, T. Oksenhendler et. al., Opt. Express 25, 12588-12600 (2017)
[3] HELIPORT: A Portable Platform for FAIR {Workflow | Metadata | Scientific Project Lifecycle} Management and Everything, O. Knodel et. al., P-RECS (2021)
[4] FAIR Computational workflows, C. Goble et. al., Data Intelligence (2020) 2, 108 (2020)

The very limited number of structurally known thionitrosyl complexes of technetium was increased by the synthesis of [Tcᴵᴵ(NS)Cl₃(PPh₃)₂] (3) and [Tcᴵᴵ(NS)Cl₃(PPh₃)(OPPh₃)] (4) and their reaction products with hydrotris(pyrazolyl)borates, {HB(pzᴿ)₃}⁻. Similar reactions were conducted with [Tcᴵ(NO)Cl₂(PPh₃)₂(CH₃CN)] and related rhenium thionitrosyls. Remarkably, most such reactions result in a rapid cleavage of the boron–nitrogen bonds of the ligands and the formation of pyrazole complexes of the two group 7 metals. Only one compound with an intact {HB(pzᴿ)₃}⁻ ligand could be isolated: the technetium(I) complex [Tcᴵ(NO)Cl(PPh₃){HB(pz)₃}] (2). Other products show the coordination of one or four neutral pyrazole ligand(s) in the coordination spheres of technetium generated by thermal decomposition of the pyrazolylborates [Tcᴵ(NO)Cl₂(PPh₃)₂(pzᴴ)] (1) and [Tcᴵ(NS)Cl(pzᴴᴹᵉ²)₄]⁺ (5). Reactions with the corresponding thionitrosylrhenium complex [Reᴵᴵ(NS)Cl₃(PPh₃)₂] require higher temperatures and only compounds with one pyrazole ligand, [Reᴵ(NS)Cl₂(PPh₃)(pzᴴᴿ)] (6a–6c), were isolated. The products were studied spectroscopically and by X-ray diffraction.

Amonton's law of friction states that the friction force is proportional to the normal force in magnitude, and the slope gives a constant friction coefficient. In this work, with molecular dynamics simulation, we study how the kinetic friction at the nanoscale deviates qualitatively from the relation. Our simulation demonstrates that the friction behavior between a nanoscale AFM tip and an elastic graphene surface is regulated by the coupling of the applied normal force and the substrate deformability. First, it is found that the normal load-induced substrate deformation could lower friction at low load while increasing it at high load. In addition, when the applied force exceeds a certain threshold another abrupt change in friction behavior is observed, i.e., the stick–slip friction changes to the paired stick–slip friction. The unexpected change in friction behavior is then ascribed to the change of the microscopic contact states between the two surfaces: the increase in normal force and the substrate deformability together lead to a change in the energy landscape experienced by the tip. Finally, the Prandtl–Tomlinson model also validates that the change in friction behavior can be interpreted in terms of the energy landscape.

The structural and magnetic properties of sputter-deposited Fe_100−xRu_x films were studied for x < 50. The crystal structure of Fe_100−xRu_x is shown to be predominantly body-centered cubic for x < 13 and to undergo a gradual transition to hexagonal close-packed in the Ru concentration range 13 < x < 20. Magnetic measurements indicate that the addition of Ru to Fe gives rise to a noncollinear magnetic alignment between Fe atoms in the body-centered cubic FeRu alloys, while the hexagonal close-packed FeRu alloys exhibit paramagnetic behavior. A simple atomistic model was used to show that the competition between ferromagnetic coupling of neighboring Fe atoms and antiferromagnetic coupling of Fe atoms across Ru atoms in cubic FeRu structures can induce noncollinear magnetic order. Magnetic multilayer structures used in thin-film magnetic devices make extensive use of both Fe and Ru layers. Our results reveal that the presence of even a small amount of Ru in Fe influences the magnetic order of Fe, which could impact the performance of these devices.

Composites consisting of magnetic fillers in polymers and elastomers enable new types of applications in soft robotics, reconfigurable actuation and sensorics. In particular, soft-bodied robots emerge as the closest synthetic system analogous to living organisms mimicking their mechanical behavior and going beyond in performance. We will introduce lightweight, durable, untethered and ultrafast soft-bodied robots that can walk, swim, levitate, transport cargo, and perform collaborative tasks being driven using magnetic far fields [1,2] and near fields [3,4]. Reconfigurable magnetic origami actuators [2] can be equipped with ultrathin magnetosensitive e-skins [5], which help to assess the magnetic state of the actuator (magnetized vs. non-magnetized), decide on its actuation pattern and control sequentiality and quality of the folding process. The on-board sensing adds awareness to soft-bodied magnetic actuators enabling them to act and be controlled similar to conventional robotic devices [6].
Magnetic composites can be readily used to realise not only actuators but also magnetic field sensors [7]. We demonstrate that printed magnetoelectronics can be stretchable, skin-conformal, capable of detection in low magnetic fields and withstand extreme mechanical deformations [8,9]. We feature the potential of our skin-conformal sensors in augmented reality settings [10,11], where a sensor-functionalized finger conducts remote and touchless control of virtual objects manageable for scrolling electronic documents and zooming maps under tiny permanent magnet [8].
Furthermore, we put forth technology to realise magnetic field sensors, which can be printed and self-heal upon mechanical damage [12]. This opens exciting perspectives for magnetoelectronics in smart wearables, interactive printed electronics and motivates further explorations towards the realisation of recyclable magnetoelectronics [13]. For the latter, we will discuss eco-sustainable, namely biocompatible and biodegradable magneto sensitive devices, which can help to minimise electronic waste and bring magnetoelectronics to new application fields in medical implants and health monitoring [6].

[1] X. Wang et al., Untethered and ultrafast soft-bodied robots. Commun. Mater. 1, 67 (2020).
[2] M. Ha et al., Reconfigurable magnetic origami actuators with on-board sensing for guided assembly. Adv. Mater. 33, 2008751 (2021).
[3] M. Richter et al., Locally addressable energy efficient actuation of magnetic soft actuator array systems. Advanced Science 2302077 (2023).
[4] L. Masjosthusmann et al., Miniaturized variable stiffness gripper locally actuated by magnetic fields. Advanced Intelligent Systems 6, 2400037 (2024).
[5] G. S. Canon Bermudez et al., Magnetosensitive e-skins for interactive devices. Adv. Funct. Mater. (Review) 31, 2007788 (2021).
[6] E. S. Oliveros Mata et al., Magnetically aware actuating composites: Sensing features as inspiration for the next step in advanced magnetic soft robotics. Phys. Rev. Appl. (Review) 20, 060501 (2023).
[7] L. Guo et al., Printable magnetoresistive sensors: A crucial step toward unconventional magnetoelectronics. Chinese Journal of Structural Chemistry (Review) 100428 (2024).
[8] M. Ha et al., Printable and stretchable giant magnetoresistive sensors for highly compliant and skin-conformal electronics. Adv. Mater. 33, 2005521 (2021).
[9] E. S. Oliveros Mata et al., Dispenser printed bismuth-based magnetic field sensors with non-saturating large magnetoresistance for touchless interactive surfaces. Adv. Mater. Technol. 7, 2200227 (2022).
[10] J. Ge et al., A bimodal soft electronic skin for tactile and touchless interaction in real time. Nature Communications 10, 4405 (2019).
[11] P. Makushko et al., Flexible magnetoreceptor with tunable intrinsic logic for on-skin touchless human-machine interfaces. Adv. Funct. Mater. 31, 2101089 (2021).
[12] R. Xu et al., Self-healable printed magnetic field sensors using alternating magnetic fields. Nature Communications 13, 6587 (2022).
[13] X. Wang et al., Printed magnetoresistive sensors for recyclable magnetoelectronics. J. Mater. Chem. A 12, 24906 (2024).

Highly simplified electrolyzer designs in the form of a membraneless alkaline electrolyzer (MAEL) allow higher current densities compared to conventional designs and result as well in lower capital expenditures. In addition, MAELs provide very good access to the electrodes, making them ideal for research to better understand bubble formation and detachment. Since there is no membrane or diaphragm to separate the products, H2 and O2, the cell design to direct the electrolyte flow is critical.

Using CFD and current simulations, an optimized cell geometry was developed to ensure constant conditions for the water splitting reaction over the entire electrode. Particle Image Velocimetry and Shadowgraphy were used to systematically study the influence of the electrolyte flow as driving force for an effective H2 and O2 separation. It is shown that below a critical Recrit the evolving bubbles are stuck on the porous electrodes and lead to a blockage of electrochemical active sites as well as to an increase of the cell potential. On the other hand, high gas purity and overall efficiency were observed at the optimal flow rate to current density ratio. Thus, the present study proves the concept of the newly developed membraneless electrolyzer.

The Geyer tin skarn in the Erzgebirge, Germany, comprises an early skarnoid stage (stage I, ~ 320 Ma) and a younger
metasomatic stage (stage II, ~ 305 Ma), but yet, the source and distribution of Sn and the physicochemical conditions
of skarn alteration were not constrained. Our results illustrate that contact metamorphic skarnoids of stage I contain
only little Sn. REE patterns and elevated concentrations of HFSE indicate that garnet, titanite and vesuvianite of stage I
formed under rock-buffered conditions (low fluid/rock ratios). Prograde assemblages of stage II, in contrast, contain two
generations of stanniferous garnet, titanite-malayaite and vesuvianite. Oscillation between rock-buffered and fluid-buffered
conditions are marked by variable concentrations of HFSE, W, In, and Sn in metasomatic garnet. Trace and REE element
signatures of minerals formed under high fluid/rock ratios appear to mimic the signature of the magmatic-hydrothermal
fluid which gave rise to metasomatic skarn alteration. Concomitantly with lower fluid-rock ratio, tin was remobilized
from Sn-rich silicates and re-precipitated as malayaite. Ingress of meteoric water and decreasing temperatures towards
the end of stage II led to the formation of cassiterite, low-Sn amphibole, chlorite, and sulfide minerals. Minor and trace
element compositions of cassiterite do not show much variation, even if host rock and gangue minerals vary significantly,
suggesting a predominance of a magmatic-hydrothermal fluid and high fluid/rock ratios. The mineral chemistry of major
skarn-forming minerals, hence, records the change in the fluid/rock ratio, and the arrival, distribution, and remobilization
of tin by magmatic fluids in polyphase tin skarn systems.

Historically, cerium has been attractive for pharmaceutical and
industrial applications. The cerium atom has the unique ability
to cycle between two chemical states (Ce(III) and Ce(IV)) and
drastically adjust its electronic configuration: [Xe] 4f15d16s2 in
response to a chemical reaction. Understanding how electrons
drive chemical reactions is an important topic. The most direct
way of probing the chemical and electronic structure of
materials is by X-ray absorption spectroscopy (XAS) or X-ray
absorption near-edge structure (XANES) in high energy reso-
lution fluorescence detection (HERFD) mode. Such measure-
ments at the Ce L3 edge have the advantage of a high
penetration depth, enabling in-situ reaction studies in a time-
resolved manner and investigation of material production or
material performance under specific conditions. But how much
do we understand Ce L3 XANES? This article provides an
overview of the information that can be extracted from
experimental Ce L3 XAS/XANES/HERFD data. A collection of
XANES data recorded on various cerium systems in HERFD
mode is presented here together with detailed discussions on
data analysis and the current status of spectral interpretation,
including electronic structure calculations.

he preparation of synthetic (Zr,U)SiO4 solid solution is challenging, as the conventional high-temperature
solid-state method limits the solubility of uranium (4 ± 1 mol%) in the orthosilicate phase due to its
thermodynamic instability. However, these compounds are of great interest as a result of (Zr,U)SiO4 solid
solutions, with uranium contents exceeding this concentration, being observed as corium phases formed
during nuclear accidents. It has been identified that hydrothermal synthesis pathways can be used for the
formation of the metastable phase, such as USiO4 . The investigation carried out in this study has indeed
led to the confirmation of metastable (Zr,U)SiO4 compounds with high uranium contents being formed. It
was found that (Zr,U)SiO4 forms a close-to-ideal solid solution with uranium loading of up to 60 mol% by
means of hydrothermal treatment for 7 days at 250 °C, at pH = 3 and starting from an equimolar reactant
concentration equal to 0.2 mol L−1 . A purification procedure was developed to obtain pure silicate com-
pounds. After purification, these compounds were found to be stable up to 1000 °C under an inert atmo-
sphere (argon). The characterisation methods used to explore the synthesis and thermal stability included
powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) and Raman spectroscopies, scanning
electron microscopy (SEM) and thermogravimetric analysis (TGA).

Micropollutants (MPs) encompass a range of human-made pollutants present in trace amounts in environmental systems. MPs include pharmaceuticals, personal care products, pesticides, persistent organic pollutants, micro- and nano-plastics, and artificial sweeteners, all posing ecological risks. Conventional municipal wastewater treatment methods often face challenges in completely removing MPs due to their chemical characteristics, stability, and resistance to biodegradation. In this research, a novel Advanced Oxidation Process, combining hydrodynamic cavitation (HC) with dissolved ozone (O3), was employed to effectively degrade succinic acid (SA), a representative ozone-resistant compound. The HC/O3 process was run to treat different synthetic effluents, focusing on evaluating the influence of O3-to-total organic carbon (TOC) ratio, cavitation number (Cv) and O3 dosage. Notably, the results from a series of 14 experiments highlighted the critical significance of a low O3-to-TOC ratio value of 0.08 mg/mg and Cv value of 0.056 in HC for achieving efficient SA removal of 41.2% from an initial SA solution (106.3 mg/L). Regarding a series of four proof-of-concept experiments and their replications, the average TOC removal reached 62% when treating wastewater treatment plant effluent spiked with SA. This significant removal rate was achieved under initial conditions: Cv of 0.02, O3-to-TOC ratio set at 0.77 mg/mg, TOC concentration of 47.7 mg/L, 106 mg/L of SA, and a temperature of 25ºC. Notably, the electrical energy per order required for the 62% reduction in TOC was a modest 12.5 kWh/m3/order, indicating the potential of the continuous HC/O3 process as a promising approach for degrading a wide range of MPs.

Understanding the electrical conductivity of warm dense hydrogen is critical for both fundamental physics and applications in planetary science and inertial confinement fusion. We demonstrate how to calculate the electrical conductivity using the continuum form of Ohm's law, with the current density obtained from real-time time-dependent density functional theory. This approach simulates the dynamic response of hydrogen under warm dense matter conditions, with temperatures around 30,000 K and mass densities ranging from 0.02 to 0.98 g/cc. We systematically address finite-size errors in real-time time-dependent density functional theory, demonstrating that our calculations are both numerically feasible and reliable. Our results show good agreement with other approaches, highlighting the effectiveness of this method for modeling electronic transport properties from ambient to extreme conditions.

Profile analysis tensiometry (PAT) with drops and bubbles is a successful methodology to characterize liquid–fluid interfaces. Questions about the most suitable size of drops and bubbles have been solved now on the basis of dimensionless numbers. The consideration of the standard deviation between measured and calculated liquid profiles as a sensitive measure for the applicability of PAT provides a tool for its correct use. For solutions of highly surface-active compounds, bulk depletion effects can cause systematic errors in the analysis of adsorption kinetics, equations of state, and the visco-elastic interfacial behavior of liquid adsorption layers. Great progress has been made in measurements of interfacial dilational rheology with large amplitude perturbations providing additional information about structure and dynamics of complex adsorption layers. Also, first attempts are successfully made to use artificial intelligence (AI) to enhance the efficiency of PAT applications. Thus, PAT has established a solid position in surface science.

The establishment of inhaled aerosols plays a significant role in risk assessment regarding air pollution and spreading of diseases. It is also of importance for evaluating lung deposition of particles and hence, the effectiveness of inhaled drug delivery systems. When it comes to air pollution or airborne diseases, there is a broad discussion whether ventilation by frequent window opening is sufficient for providing a sufficient amount of fresh air or if technical air purification devices based on e.g. HEPA filters are page better solutions for public spaces. Furthermore, there is another discussion ongoing, whether a well-guided laminar flow or a high degree of mixing within a room is more beneficial. The latter, on the one hand distributes the potentially virus-laden aerosols in the whole room, but on the other hand reduces the peak concentrations of these aerosols clouds by magnitudes.

The objective of this study is to answer to these queries by performing aerosol propagation experiments in order to estimate the potential aerosol inhalation of people in dynamic situations. To achieve this, an aerosol generator is used for aerosolizing a solution of water/MgCl2, which is collected in removible filters located in breathing masks used by the people during the experiment. The quantification of the inhaled aerosol is carried out by extracting the Mg from the mask and measuring it using inductively coupled plasma mass spectromestry technique (ICP-MS). Experiments will be performed in a demonstrator room under different flow conditions. The data from different scenarios will be processed in order to obtain a transference function that can relate the aerosol source with the aerosol receivers.

Background: Hypoxia remains a challenge for the therapeutic management of head and neck squamous cell carcinoma (HNSCC). The combination of radiotherapy with nimorazole has shown treatment benefit in HNSCC, but the precise underlying molecular mechanisms remain unclear. Purpose: To assess and to characterize the transcriptomic/epigenetic landscape of HNSCC tumor models showing differential therapeutic response to fractionated radiochemotherapy (RCTx) combined with nimorazole. Materials/methods: Bulk RNA-sequencing and DNA methylation experiments were conducted using untreated and treated HNSCC xenografts after 10 fractions of RCTx with and without nimorazole. These tumor models (FaDu, SAS, Cal33, SAT and UT-SCC-45) previously showed a heterogeneous response to RCTx with nimorazole. The prognostic impact of candidate genes was assessed using clinical and gene expression data from HNSCC patients treated with primary RCTx within the DKTK-ROG. Results: Nimorazole responder and non-responder tumor models showed no differences in hypoxia gene signatures However, non-responder models showed upregulation of metabolic pathways. From that, a subset of 15 differentially expressed genes stratified HNSCC patients into low and high-risk groups with distinct outcome. Conclusion: In the present study, we found that nimorazole non-responder models were characterized by upregulation of genes involved in Retinol metabolism and xenobiotic metabolic process pathways, which might contribute to identify mechanisms of resistance to nitroimidazole compounds and potentially expand the repertoire of therapeutic options to treat HNSCC.

I present an overview of current ab initio path integral Monte Carlo (PIMC) capabilities to simulate warm dense matter and related extreme states. In the first part, I introduce the PIMC method and summarize recent developments for the uniform electron gas. In the second part, I show how emerging PIMC simulations of real systems such as warm dense hydrogen and beryllium allow for novel ways to interpret x-ray Thomson scattering (XRTS) measurements. This is demonstrated for an experimental dataset for strongly compressed beryllium measured at the National Ignition Facility (NIF).

The shearing of a particle bed composed of two or more species results in spontaneous
segregation. This poses problems in many industries, where the mixing of granules and powders
is a common process and a homogeneous product is desired. In this work, the segregation
dynamics occurring in a horizontal rotating drum filled with two granular species that only
differ in density is investigated. In this system, radial segregation is relatively fast and occurs
over the course of a few drum rotations. State-of-the art techniques allow the study of
segregation dynamics at the end walls of a drum, as well as the observation of slow axial
dynamics and the steady state of radial mixing inside the drum bulk. They do not allow,
however, continuous observation of the transient radial mixing in the bulk. Using the ultrafast
X-ray computer tomography it is possible to take cross-sectional images through the opaque
granular systems at 1000 frames per second. The high-speed image sequences from intermediate
planes of the drum can reveal the segregation dynamics in the bulk. Here we present
experimental results from the transient state of radial mixing for a binary granular system with
density difference (density ratio 2.8) and equal size (4 mm) spherical beads in a half-filled drum.
Using a dimensionless mixing index (M), we compare the dynamics of radial mixing and
segregation in transverse planes in the bulk of the drum, captured with UFXCT, with the
dynamics from the circular end caps to highlight wall effects. We also compare two dynamic
models for radial mixing and consider the effect of flow on mixing dynamics. We find that
second-order dynamics fit better the data than the commonly used first-order, since it accounts
for the overshooting mixing dynamics occurring at higher drum speeds. We also find that,
compared to the end cap, the dense particle segregation core is larger in the bulk plane and the
overshooting in the mixing index is smaller, suggesting a correlation between mixing and flow
characteristics, such as the dynamic angle of repose. Our results, because of better describing
overmixing, are highly relevant to the pharmaceutical, food and cement industrie

The transient mixing dynamics of an initially segregated binary granular system in a half-filled rotating drum are investigated. The granular system consists of spherical beads having identical size. The density ratio between the two granular phases is 2.8. With its ability to scan three-dimensional opaque systems with a high frequency, the ultrafast X-ray computed tomography is used to capture the transient and steady-state segregation dynamics in the bulk. The segregation dynamics are also compared to those at the circular end-wall caps, which have been captured with a camera. The results show an axial migration of the denser particles towards the bulk and, more importantly, second-order overshooting dynamics in the radial mixing index, which tend to increase with the Froude number. The results will find application in industrial systems, where rapid mixing occurs. We also believe the presented data can serve as validation for future three-dimensional simulations focusing on the transient formation of segregation patterns in the bulk.

Deuterium insertion was used to tune the magnetic properties of Y_0.9Tb_0.1Fe₂ Laves phase towards an itinerant electron metamagnetic (IEM) behavior. The latter is highly sensitive to chemical changes and external parameters. The structural and magnetic properties of Y_0.9Tb_0.1Fe₂D_4.3 were investigated using various neutron powder diffraction experiments in addition to magnetic measurements under steady and pulsed high magnetic fields up to 60 T. The deuteride crystallizes in a monoclinic structure (P_c space group) with 4.3 D atoms located in 18 tetrahedral interstitial sites. At zero field, it undergoes a ferrimagnetic-antiferromagnetic (FiM-AFM) transition at T_M0 = 90 K, accompanied by an anisotropic magnetostriction and a negative cell volume expansion of 0.6 %. A second AFM-PM transition is observed at 146 K. Under pulsed magnetic field at 4.2 K, the deuteride displays a multistep magnetic behavior from ferrimagnetic to a ferromagnetic state, which can be attributed to a stepwise rotation of the Tb moments. The ZFC-FC magnetization curves at low fields exhibit an irreversibility below 90 K, followed by a sharp decrease in magnetization at the FM-AFM transition. Between 90 K and 130 K, the magnetization curves display an IEM behavior, with the transition field increasing linearly with temperature.

In spatially inverted systems, the complex entanglement of Dzyaloshinskii-Moriya interaction (DMI) and other magnetic anisotropies, mediated by spin-orbit coupling (SOC), influences the emergence and dynamics of the chiral spin textures such as skyrmion. The competing and unified effect of these anisotropies - which is expected to amplify the skyrmionics response in the quantum transport phenomena - is not yet known. Here, we investigate this template and engineer the topological Hall effect (THE) arising from chiral spin texture in a range of La_0.7Sr_0.3MnO₃/CaIrO₃ superlattices. The strength of SOC and interfacial DMI are controlled via the architectural design and charge transfer across the interface. All the superlattices display anomalous Hall effect, accompanied by the hump like feature. In (L₃I_y)₄ (y = 4, 6, and 8) superlattices, the humplike feature that is deemed as the THE is intrinsic in nature and stems from the chiral spin texture. For the intermediate strength of SOC, unique eightfold anisotropic magnetoresistance oscillations manifest owing to the modulation of the magnetic easy axis in the presence of competing anisotropies. For this superlattice, THE shows remarkable enhancement of the order such that it takes complete precedence over anomalous contribution. The thicker superlattice with higher fraction of charge transfer augments ferromagnetic interactions, and the artificial THE appears as a consequence of a dual-channel anomalous Hall effect. This manipulation of the THE is intricately connected to the concurrent presence of magnetic anisotropies, altering the dynamics of chiral spin texture. These findings expand the understanding of the corroborative contributions of competing anisotropies and yield a comprehensive control of chiral properties - a dimension for the utility in next-generation spintronics technologies.

The Remote Sensing (RS) field continuously grapples with the challenge of transforming satellite data into actionable information. This ongoing issue results in an ever-growing accumulation of unlabeled data, complicating interpretation efforts. The situation becomes even more challenging when satellite data must be used immediately to identify the effects of a natural hazard. Self-supervised learning (SSL) offers a promising approach for learning image representations without labeled data. Once trained, an SSL model can address various tasks with significantly reduced requirements for labeled data. Despite advancements in SSL models, particularly those using contrastive learning methods like MoCo, SimCLR, and SwAV, their potential remains largely unexplored in the context of instance segmentation and semantic segmentation of satellite imagery. This study integrates SwAV within an auto-encoder framework to detect landslides using deca-metric resolution multi-spectral images from the globally-distributed large-scale landslide4sense (L4S) 2022 benchmark dataset, employing only 1% and 10% of the labeled data. Our proposed SSL auto-encoder model features two modules: SwAV, which assigns features to prototype vectors to generate encoder codes, and ResNets, serving as the decoder for the downstream task. With just 1% of labeled data, our SSL model performs comparably to ten state-of-the-art deep learning segmentation models that utilize 100% of the labeled data in a fully supervised manner. With 10% of labeled data, our SSL model outperforms all ten fully supervised counterparts trained with 100% of the labeled data.

Research software is a central pillar in the scientific work in general, in the Helmholtz Association and in particular at the Helmholtz-Zentrum Dresden - Rossendorf e.V. (HZDR). The software policy at the HZDR supports researchers in their independence and ability to act and is a framework that provides orientation. It gives advice and makes recommendations for the whole software lifecycle from development and documentation to publication and distribution as well as maintenance of the research software.

The HZDR software policy is derived from a model policy provided by the Task Group Research Software of the Helmholtz Open Science Office. Adaptations were made, for example, regarding the recommended software quality ensurance measures based on the software application classes suggested by the German Aerospace Center (DLR) as well as the choice of Open-Source Software (OSS) licenses. A selection process and decision tree were defined to recommend the preferred use a specific set of OSS licenses at the HZDR.

The introduction of a policy at HZDR and for each of the research centres in the Helmholtz Association involves not only behavioural but also cultural change in the whole research association and all related research groups. The overall objectives are to achieve better sustainability and higher quality in research software engineering leading to better verifiability, traceability and reproducibility of scientific results.

The electron-phonon interaction is in many ways a solid state equivalent of quantum electrodynamics. Being always present, the e-p coupling is responsible for the intrinsic resistance of metals at finite temperatures, making it one of the most fundamental interactions present in solids. In typical metals, different regimes of e-p scattering are separated by a characteristic phonon energy scale—the Debye temperature. However, in metals harboring very small Fermi surfaces a new scale emerges—the Bloch-Grüneisen temperature. This is a temperature at which the average phonon momentum becomes comparable to the Fermi momentum of the electrons. Here we report sub-Kelvin transport and sound propagation experiments on the Dirac semimetal ZrTe₅. The combination of the simple band structure with only a single small Fermi surface sheet allowed us to directly observe the Bloch-Grüneisen temperature and its consequences on electronic transport of a 3D metal in the limit where the small size of the Fermi surface leads to effective restoration of translational invariance of free space. Our results indicate that on entering this hydrodynamic transport regime, the viscosity of the Dirac electronic liquid undergoes an anomalous increase beyond the theoretically predicted T⁵ temperature dependence. Extension of our measurements to strong magnetic fields reveal that, despite the dimensional reduction of the electronic band structure, the electronic liquid retains characteristics of the zero-field hydrodynamic regime up to the quantum limit. This is vividly reflected by an anomalous suppression of the amplitude of quantum oscillations seen in the Shubnikov-de Haas effect.

We investigated the magnetic and magnetoelastic properties of MnSc₂Se₄ single crystals at low temperature under a magnetic field directed along the crystallographic [111] axis. The magnetization data at low temperature show a linear increase with magnetic field, until saturation is reached above 15 T. In ultrasound, a longitudinal acoustic mode shows a softening in field, which is absent for a transverse acoustic mode.We discuss these results using a microscopic model based on the framework of linear spin-wave theory. The magnetic and magnetoelastic data are qualitatively reproduced by considering magnon-phonon interactions arising from exchange-striction coupling between the crystal lattice and spin-wave fluctuations in the zero-temperature limit.

Spinon-magnon mixing was recently reported in botallackite Cu₂(OH)₃Br with a uniaxially compressed triangular lattice of Cu²⁺ quantum spins [H. Zhang et al., Phys. Rev. Lett. 125, 037204 (2020)]. Its nitrate counterpart rouaite, Cu₂(OH)₃NO₃, has a highly analogous structure and might be expected to exhibit similar physics. To lay a foundation for research on this material, we clarify rouaite’s magnetic phase diagram and identify both low-field phases. The low-temperature magnetic state consists of alternating ferromagnetic and antiferromagnetic chains, as in botallackite, but with additional canting, leading to net moments on all chains which rotate from one chain to another to form a 90° cycloidal pattern. The higher-temperature phase is a helical modulation of this order, wherein the spins rotate from one Cu plane to the next. This extends to zero temperature for fields perpendicular to the chains, leading to a set of low-temperature field-induced phase transitions. Rouaite may offer another platform for spinon-magnon mixing, while our results suggest a delicate balance of interactions and high tunability of the magnetism.

We present a thorough experimental investigation on single crystals of the rare-earth based frustrated quantum antiferromagnet Pr₃BWO₉, a purported spin-liquid candidate on the breathing kagome lattice. This material possesses a disordered ground state with an unusual excitation spectrum involving a coexistence of sharp spin waves and broad continuum excitations. Nevertheless, we show through a combination of thermodynamic, magnetometric, and spectroscopic probes with detailed theoretical modeling that it should be understood in a completely different framework. The crystal field splits the lowest quasidoublet states into two singlets moderately coupled through frustrated superexchange, resulting in a simple effective Hamiltonian of an Ising model in a transverse magnetic field. While our neutron spectroscopy data do point to significant correlations within the kagome planes, the dominant interactions are out-of-plane, forming frustrated triangular spin-tubes through two competing ferro-antiferromagnetic bonds. The resulting ground state is a simple quantum paramagnet, where the presence of strongly hyperfine-coupled nuclear moments and weak structural disorder causes significant modifications to both thermodynamic and dynamic properties.

Recent promising results from inertial fusion energy (IFE) facilities, such as the National Ignition Facility in the USA, have sparked a strong interest in IFE technologies. Because it is a multiscaled problem from a simulation standpoint, significant effort is required to accurately model the dense plasmas on various length and time scales, which is crucial for developing IFE technology. One of the main challenges in modeling is creating reliable simulation tools to study the dynamic dielectric and transport properties of dense plasmas across different temperature and density ranges. Quantum many-body theory is crucial in developing a dependable method for computing these properties, provided the density response function of plasmas is known. This presentation discusses the advanced simulation methods being used and developed at the Center of Advanced Systems Understanding [1-4] for this property and the associated computational and work expenses.

[1] Tobias Dornheim, Zhandos A. Moldabekov, Kushal Ramakrishna, Panagiotis Tolias, Andrew D. Baczewski, Dominik Kraus, Thomas R. Preston, David A. Chapman, Maximilian P. Böhme, Tilo Döppner, Frank Graziani, Michael Bonitz, Attila Cangi, Jan Vorberger, Electronic density response of warm dense matter, Phys. Plasmas 30, 032705 (2023).
[2] Zhandos Moldabekov, Jan Vorberger, Tobias Dornheim, Density Functional Theory Perspective on the Nonlinear Response of Correlated Electrons across Temperature Regimes, J. Chem. Theory Comput. 2022, 18, 5, 2900–2912
[3] Zhandos A. Moldabekov, Michele Pavanello, Maximilian P. Böhme, Jan Vorberger, and Tobias Dornheim, Linear-response time-dependent density functional theory approach to warm dense matter with adiabatic exchange-correlation kernels, Phys. Rev. Research 5, 023089 (2023)
[4] Maximilian Böhme, Zhandos A. Moldabekov, Jan Vorberger, and Tobias Dornheim, Static Electronic Density Response of Warm Dense Hydrogen: Ab Initio Path Integral Monte Carlo Simulations, Phys. Rev. Lett. 129, 066402 (2022)

In this experimental study, we explore the dynamics of the thermal boundary layer in liquid metal Rayleigh–Bénard convection, covering the parameter ranges of 0.026 ≤ Prandtl numbers (Pr) ≤0.033 and Rayleigh numbers (Ra) up to 2.9×10^9. Our research focuses on characterising the thermal boundary layer near the top plate of a cylindrical convection cell with an aspect ratio of 0.5, distinguishing between two distinct regions: the shear-dominated region around the centre of the top plate and a location near the side wall where the boundary layer is expected to be affected by the impact or ejection of thermal plumes. The dependencies of the boundary layer thickness on Ra at these positions reveal deviating scaling exponents with the difference diminishing as Ra increases. We find stronger fluctuations in the boundary layer and increasing deviation from the Prandtl–Blasius–Pohlhausen profile with increasing Ra, as well as in the measurements outside the centre region. Our data illustrate the complex interplay between flow dynamics and thermal transport in low-Pr convection.

Magnetic refrigeration based on the principle of the magnetocaloric effect (MCE) in magnetic solids has been considered as a prospective cooling technology. Exploring suitable magnetocaloric materials (MCMs) is a vital prerequisite for practical applications. Herein, an excellent cryogenic MCM—the B-site-ordered Gd₂CuTiO₆ double perovskite (DP) oxide—which exhibits the largest MCE among known Gd-based DP oxides, is identified. Such enhanced cryogenic MCE in the Gd₂CuTiO₆ DP oxide likely stems from the exchange interaction effect between Gd-4f and Cu-3d magnetic sublattices. Under a magnetic field change of 0–7 T, the maximum magnetic entropy change (−ΔS_T ^max) of the Gd₂CuTiO₆ DP oxide reaches 51.4 J kg⁻¹ K⁻¹ (378.2 mJ cm⁻³ K⁻¹), which is much larger than that of the commercialized magnetic refrigerant Gd₃Ga₅O₁₂, which is 38.3 J kg⁻¹ K⁻¹ (271.2 mJ cm⁻³ K⁻¹), and it is also superior to most of the recently reported benchmarked cryogenic MCMs, indicating the possibility for practical applications. This work also provides a productive route for future cryogenic MCM design by harnessing 4f–3d exchange interactions.

In case it is desirable to dispose of inventories of separated civil PuO2 that have no further use, a
suitable immobilisation matrix is required, prior to disposition in a geological disposal facility. Conversion
of Pu into a mixed oxide (MOX)-type material with characteristics suitable for disposal has previously
been suggested, but not yet demonstrated at laboratory or industrial scale. We here demonstrate the
feasibility of different synthesis routes for simulant ‘‘disposal-MOX’’, using Th 4+ as a Pu4+ surrogate and
containing Gd3+ in a suitable quantity to ensure criticality control. Compositions of (U(1(x+y))ThxGdy)O2d,
where x = 0.1, 0.2 and x : y = 10 : 1 or 100 : 1, were synthesised by a solid state route mimicking the industrial
MIMAS MOX fuel fabrication process, or through an oxalic wet co-precipitation
method. Both synthesis routes gave a single phase fluorite structure upon heat-treatment at 1700 1C, with a
grain size similar to (Pu,U)O2 MOX fuel. The relative density of the sintered pellets was 490% but was
highest in co-precipitated materials, with Th4+ and Gd3+ additions more homogenously distributed. Though
no unincorporated ThO2 or Gd2O3 was observed in any sample, Th and Gd-rich regions were more
prevalent in materials produced through solid state synthesis, in accordance with MIMAS MOX fuel
microstructures. The incorporation of Gd3+ within the fluorite lattice, which is favourable from a criticality
control perspective in a Pu wasteform, was found to be charge balanced via the generation of oxygen
vacancy defects, but not U5+. These results demonstrate feasible synthesis routes for a disposal-MOX
wasteform product via both solid state and wet co-precipitation fabrication routes.

Positron annihilation spectroscopy (PAS) is a precise probe of point defects in bulk and nanomaterials, such as semiconductors. Positrons localize in the neutral and negatively charged open volume defects, i.e. vacancies and their agglomerations, extended defects or pores. The time to the inevitable annihilation of the positron with the electron depends on the local electron density and scales with the open volume size. Positrons pre-accelerated to a given kinetic energy are implanted into solids, allowing depth profiling. In a defect, their lifetime increases and the energetics of the annihilation photons changes. These characteristics are measured using two main measurement techniques, namely positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler broadening spectroscopy (cDBS or cDB-PAS), respectively. Both techniques are available at the large-scale user facility ELBE at HZDR, Germany. PALS allows the evaluation of defect size and concentration, while cDBS provides sensitivity to positron annihilation with valence and core electrons, the latter a fingerprint of the nearest neighbor atoms.
This contribution discusses the role of open volume defects and defect chemistry in the context of heavily doped semiconductors, such as sulfur- and telluride-doped GaAs [1] and Si [2], Al doped ZnO (AZO) [3], or pulsed laser and flash lamp annealed GeSn [4]. We will show that incomplete recrystallization processes resulting from intense pulsed laser melting (PLM) and flash lamp annealing (FLA) are related to defect distribution and electrical activation efficiency in chalcogenide-implanted GaAs. Similarly, in thermally treated chalcogenide-implanted Si, vacancy accumulation processes correlate with variations in carrier concentration and electron mobility. A combination of PAS measurements and DFT calculations allows to translate the experimental results into defect types/sizes and highlights the role of vacancy-dopant complexes for electrical deactivation. On the other hand, the relationship between the crystal quality of AZO films, i.e. single, polycrystalline or amorphous structures, and deposition parameters, such as growth pressure and thickness, can be related to the concomitant increase in vacancy agglomeration size and density. We will discuss the role of dislocations and Sn-decorated germanium vacancies, resulting from Sn diffusion and clustering due to PLM, on the electrical properties of GeSn. The change in defect microstructure depending on the Sn content will be highlighted, too. Finally, a new perspective for PAS is given, where the simultaneous light illumination together with positron measurements will allow new insights into sub-bandgap defect levels in semiconductors, e.g. in GaN.
[1] J. Duan et al., J. Appl. Phys., 134 (2023) 95102
[2] M.S. Shaikh et al., Appl. Surf. Sci., 567 (2021) 150755
[3] R.M. Maffei et al., Appl. Surf. Sci., 665 (2024) 160240
[4] O. Steuer et al., J. Phys. Condens. Matter, 36 (2024) 085701

In contrast to corresponding nitrosyl compounds, thionitrosyl complexes of rhenium and technetium are rare. Synthetic access to the thionitrosyl core is possible by two main approaches: (i) the treatment of corresponding nitrido complexes with S₂C₂ and (ii) by reaction of halide complexes with trithiazyl chloride. The first synthetic route was applied for the synthesis of novel rhenium and technetium thionitrosyls with the metals in their oxidation states “+1” and “+2”. [MᵛNCl₂(PPh₃)₂], [MᵛNCl(PPh₃)(LOMe)] and [MᵛᶦNCl₂(LOMe)] (M = Re, Tc; {LOMe}⁻ = (η⁵-cyclopentadienyl)tris(dimethyl phosphito-P)cobaltate(III)) complexes have been used as starting materials for the synthesis of [Reᴵᴵ(NS)Cl₃(PPh₃)₂] (1), [Reᴵᴵ(NS)Cl₃(PPh₃)(OPPh₃)] (2), [Reᴵᴵ(NS)Cl(PPh₃)(LOMe)]⁺ (4a), [Reᴵᴵ(NS)Cl₂(LOMe)] (5a), [Tcᴵᴵ(NS)Cl(PPh₃)(LOMe)]⁺ (4b) and [Tcᴵᴵ(NS)Cl₂(LOMe)] (5b). The triphenylphosphine complex 1 is partially suitable as a precursor for ongoing ligand exchange reactions and has been used for the synthesis of [Reᴵ(NS)(PPh₃)(Et₂btu)₂] (3a) (HEt₂btu = N,N-diethyl-N′-benzoyl thiourea) containing two chelating benzoyl thioureato ligands. The novel compounds have been isolated in crystalline form and studied by X-ray diffraction and spectroscopic methods including IR, NMR and EPR spectroscopy and (where possible) mass spectrometry. A comparison of structurally related rhenium and technetium complexes allows for conclusions about similarities and differences in stability, reaction kinetics and redox behavior between these 4d and 5d transition metals.

Die Protonentherapie zeichnet sich durch steile Dosisgradienten und damit einen gut lokalisierbaren Energieübertrag aus. Um dieses Potential voll ausschöpfen zu können, werden weltweit Möglichkeiten erforscht, die Dosisdeposition und insbesondere die Reichweite der Protonen im Patienten zu verifizieren. Eine vielversprechende, erst im letzten Jahrzehnt entdeckte Methode ist das Prompt Gamma-Ray Timing (PGT), das auf der Abhängigkeit der detektierten Flugzeitverteilung prompter Gammastrahlung von der Transitzeit der Protonen im Patienten beruht. In dieser Arbeit wird eine Geant4-Simulation zur Vorhersage der PGT-Spektren bei Bestrahlung eines PMMA-Phantoms entwickelt und durch den Vergleich mit experimentellen Daten validiert. Sowohl die Emissionsausbeute prompter Gammastrahlung im Phantom als auch die Detektionsrate werden abhängig von der Protonenenergie analysiert. Zur Vergleichbarkeit mit den gemessenen Spektren wird eine mehrschrittige Prozessierung der Simulationsergebnisse vorgestellt. Schließlich wird die Simulation genutzt, um die Sensitivität der PGT-Methode auf Reichweitenänderungen zu demonstrieren. Dafür können in das Phantom Cavitäten unterschiedlicher Dicke und verschiedenen Materials eingefügt werden. Für geeignet gewählte Verteilungsparameter der simulierten PGT-Spektren wird deren detektierte Änderung mit der bekannten induzierten Reichweitenänderung ins Verhältnis gesetzt. Die so bestimmte Sensitivität ist mit früheren Ergebnissen für gemessene Spektren im Rahmen der Unsicherheiten in Übereinstimmung.

The mixed state transport properties of type-II superconductors are strongly influenced by the dynamic behavior of quantized magnetic fluxoids around the critical temperature (Tc), where a combination of normal and superconducting properties is exhibited. To understand the mixed state transport properties of type-II superconducting NbN ultrathin films (2D) we measured sheet resistance (RxxM) and Hall resistance (RxyM) of a 5-nm-thick NbN film around Tc (10.75 K) at temperatures 10.40, 10.68, and 10.77 K. Hall resistance (HR) was measured in external out-of-plane and in-plane magnetic fields up to 6 T, using 100 μA and 1 mA driving current in Van der Pauw geometry. The electric field of applied bias and Lorentz force of applied external magnetic field causes a movement of the normal conducting electrons within each fluxoid. The moving fluxoids cause dissipation and generation of Hall voltage. We developed a macroscopic analysis of the Hall resistance arising from fluxoids, to advance the differentiation between dissipating current and superconducting currents in type-II superconductors at Tc. We have extracted the number of normal conducting carriers per fluxoid and areal density and mobility of the fluxoids in dependence on the external magnetic field. This differentiation provides valuable insights into the dissipation mechanisms observed during transport measurements, e.g., after localized heating due to single photon absorption in nanostructured type-II superconductors. Furthermore, the developed macroscopic analysis of Hall resistance of fluxoids shows promising potential for investigating the fundamental aspects of fluxoid-defect interactions in type-II superconductors. © 2024 authors. Published by the American Physical Society.

Semiconductor spin qubits combine excellent quantum performance with the prospect of manufacturing quantum devices using industry-standard metal-oxide-semiconductor (MOS) processes. This applies also to ion-implanted donor spins, which further afford exceptional coherence times and large Hilbert space dimension in their nuclear spin. Here multiple strategies are demonstrated and integrated to manufacture scale-up donor-based quantum computers. 31PF_2 molecule implants are used to triple the placement certainty compared to 31P ions, while attaining 99.99% confidence in detecting the implant. Similar confidence is retained by implanting heavier atoms such as 123Sb and 209Bi, which represent high-dimensional qudits for quantum information processing, while Sb_2 molecules enable deterministic formation of closely-spaced qudits. The deterministic formation of regular arrays of donor atoms with 300 nm spacing is demonstrated, using step-and-repeat implantation through a nano aperture. These methods cover the full gamut of technological requirements for the construction of donor-based quantum computers in silicon.

A data-driven framework is presented for building spin-aware machine-learning interatomic potentials (ML-IAPs) for large-scale spin-lattice dynamics simulations. The ML-IAPs are constructed by coupling a collective atomic spin model with an ML-IAP. Together, they represent a potential energy surface from which the mechanical forces on the atoms and the precession dynamics of the atomic spins are computed. Both the atomic spin model and the ML-IAP are parametrized on data from first-principles methods - Density Functional Theory (DFT) using Spectral Neighbor Analysis Potential (SNAP) descriptors. The generated spin-aware ML-IAP can be directly used in the LAMMPS package to perform coupled spin-molecular dynamics simulations. Leveraging the framework enables performing simulations to study magnetic materials at large lengthscales and longer timescales with first-principles accuracy.

Despite its broad potential applications, substitution of carbon by transition metal atoms in graphene has so far been explored only to a limited extent. We report the realization of substitutional Mn doping of graphene to a record high atomic concentration of 0.5%, which was achieved using ultralow-energy ion implantation. By correlating the experimental data with the results of ab initio Born−Oppenheimer molecular dynamics calculations, we infer that direct substitution is the dominant mechanism of impurity incorporation. Thermal annealing in ultrahigh vacuum provides efficient removal of surface contaminants and additional implantation-induced disorder, resulting in Mn-doped graphene that, aside from the substitutional Mn impurities, is essentially as clean and defect-free as the as-grown layer. We further show that the Dirac character of graphene is preserved upon substitutional Mn doping, even in this high concentration regime, making this system ideal for studying the interaction between Dirac conduction electrons and localized magnetic moments. More generally, these results show that ultralow energy ion implantation can be used for controlled functionalization of graphene with substitutional transition-metal atoms, of relevance for a wide range of applications, from magnetism and spintronics to single-atom catalysis.

This study assesses the impact of Treated Distillate Aromatic Extract (TDAE) oil, at concentrations of 0–20 parts
per hundred rubber (phr), on the glass transition temperature (Tg) of High Vinyl/Low Styrene Styrene-Butadiene
Rubber (HVLSS-SBR), polybutadiene rubber (BR), and their blends with weight ratios of 70/30 and 50/50. Using
Dynamic Mechanical Analysis, Broadband Dielectric Spectroscopy, and Positron Annihilation Lifetime Spectroscopy,
we found that TDAE modifies Tg and fractional free volume (Fv) differently across materials. In HVLSSSBR,
TDAE reduced Tg by approximately 10 ◦C and increased Fv by 0.8 %. In BR, TDAE raised Tg by 5–7 ◦C
without altering Fv. The 70/30 blend showed no Tg change but a 0.6 % Fv increase. For the 50/50 blend, one
Havriliak-Negami equation indicated a Tg rise of 2–3 ◦C and a 0.4 % Fv increase. A two-equation analysis
revealed a 6 ◦C Tg increase and 0.9 % Fv boost in the BR-rich phase, versus a 2 ◦C rise and 0.3 % Fv uptick in the
HVLSS-SBR-rich phase. The sequence of compatibility, influenced by TDAE, is crystalline BR > amorphous BR >
HVLSS-SBR >70/30 blend >50/50 blend. This study provides valuable insights into the behavior of TDAE oil in
rubber blends and can serve as a basis for further research in this field.

The design of novel materials for various scientific and technological purposes such
as in electronics and the energy sector has in recent years benefitted from the
introduction of data-driven design strategies. Here, the power of this approach is
leveraged for two exemplary materials classes.
The recent surprising experimental realization of non-van der Waals 2D compounds
obtained from non-layered crystals [1] foreshadows a new direction in 2D systems
research. We present several dozens of candidates of this novel materials class
derived from applying data-driven research methodologies in conjunction with
autonomous ab initio calculations [2,3,4]. The candidates exhibit a wide range of
appealing electronic, optical, and magnetic properties making them an attractive
platform for fundamental and applied nanoscience.
Also high-entropy materials have recently attracted significant interest due to their
favorable properties within mechanically and thermally demanding environments.
For their actual design, predictive synthesizability descriptors such as the disordered
enthalpy-entropy descriptor (DEED) [5] are crucial prerequisites. We present an
extensive validation of the predictive power of this approach and its prospective
combination with enthalpy corrections for ionic materials [6] for the efficient
computational design of high-entropy compounds for extreme conditions.
[1] A. Puthirath Balan et al., Nat. Nanotechnol. 13, 602 (2018).
[2] R. Friedrich et al., Nano Lett. 22, 989 (2022).
[3] T. Barnowsky et al., Adv. Electron. Mater. 9, 2201112 (2023).
[4] T. Barnowsky et al., Nano Lett. 24, 3874 (2024).
[5] S. Divilov et al., Nature 625, 66 (2024).
[6] R. Friedrich et al., npj Comput. Mater. 5, 59 (2019).

The computational design of ionic materials such as ceramics relies on accurate
enthalpies. While standard electronic structure approaches based on density functional
theory can provide quantitatively accurate results for intermetallic compounds, they fail
to yield a proper description of the thermodynamics of ionic materials such as oxides as
the mean absolute errors for formation enthalpies are on the order of several hundred
meV/atom [1]. This hinders the materials design of for instance high-entropy ceramics
or lower dimensional systems such as 2D oxides.
To address this pressing issue, we have recently developed the coordination corrected
enthalpies (CCE) method based on the number of cation-anion bonds and the cation
oxidation states. This correction scheme founded on the bonding topology decreases
the prediction errors by almost an order of magnitude down to the room temperature
thermal energy scale of ~25 meV/atom for oxides, halides, and nitrides [1,2]. It is also
capable of correcting the relative stability of crystal polymorphs. The efficient
implementation of this scheme into the AFLOW framework for materials design in the
form of the AFLOW-CCE module [3] enables now the correction of enthalpies in large
materials databases as well as for the construction of convex hull phase diagrams.
These computational advances are an important enabler for the design of novel highentropy
materials. The reliable computational modelling of such systems can be
realized by the partial occupation algorithm [4] by expanding the disordered system into
a large set of ordered structures. For the actual design of these compositionally
complex disordered high-entropy systems, predictive synthesizability descriptors such
as the disordered enthalpy-entropy descriptor (DEED) [5] are crucial prerequisites. It
critically relies on the accuracy of the enthalpies of all competing phases within the
chemical space of interest as provided by the CCE method.
Literature:
[1] R. Friedrich et al., npj Comput. Mater. 2019, 5, 59. [2] R. Friedrich & S. Curtarolo, J.
Chem. Phys. 2024, 160, 042501. [3] R. Friedrich et al., Phys. Rev. Mater. 2021, 5,
043803. [4] K. Yang et al., Chem. Mater. 2016, 28, 6484. [5] S. Divilov et al., Nature
2024, 625, 66 (2024).

While 2D materials are traditionally derived from bulk layered crystals bonded by weak van
der Waals (vdW) forces, the recent surprising experimental realization of non-vdW 2D compounds
obtained from non-layered transition metal oxides [1] foreshadows a new direction in
2D systems research.
As outlined by our recent data-driven investigations [2, 3], these materials exhibit in particular
unique magnetic properties owing to the magnetic cations at the surface of the sheets. Based on
screening the AFLOW materials database first by a structural criterion for representatives similar
to the experimentally realized systems and focusing then on magnetic compounds, we obtain
12 magnetic candidates (Fig. 1a). Despite of a few ferromagnetic systems, even for the
antiferromagnetic representatives, the surface spin polarizations are diverse ranging from moderate
to large values modulated in addition by ferromagnetic and antiferromagnetic in-plane
coupling (Fig. 1b). At the same time, chemical tuning by surface passivation provides a valuable
handle to further control the magnetic properties of these novel 2D compounds and eventually
to even induce ferromagnetism as demonstrated by hydrogenation of 2D CdTiO3 [4] (Fig. 1c).
These features thus make these compounds an attractive platform for fundamental as well as
applied nanoscience and in particular spintronics.
[1] A. Puthirath Balan et al., Nat. Nanotechnol. 13, 602 (2018).
[2] R. Friedrich et al., Nano Lett. 22, 989 (2022).
[3] T. Barnowsky et al., Adv. Electron. Mater. 9, 2201112 (2023).
[4] T. Barnowsky et al., Nano Lett. 24, 3974 (2024).

Raw data and metadata related to the publication

Emitters based on photoconductive materials excited by ultrafast lasers are well-
established and popular devices for THz generation. However, so far, these emitters – both
photoconductive antennas and large area emitters - were mostly explored using driving lasers
with moderate average powers (either fiber lasers with up to hundreds of milliwatts or Ti:Sapphire
systems up to few watts). In this paper, we explore the use of high-power, MHz repetition
rate Ytterbium (Yb) based oscillator for THz emission using a microstructured large-area
photoconductive emitter, consist of semi-insulating GaAs with a 10 × 10 mm2 active area. As a
driving source, we use a frequency-doubled home-built high average power ultrafast Yb-oscillator,
delivering 22 W of average power, 115 fs pulses with 91 MHz repetition rate at a central
wavelength of 516 nm. When applying 9 W of average power (after an optical chopper with
a duty cycle of 50%) on the structure without optimized heatsinking, we obtain 65 μW THz
average power, 4 THz bandwidth; furthermore, we safely apply up to 18 W of power on the
structure without observing damage. We investigate the impact of excitation power, bias voltage,
optical fluence, and their interplay on the emitter performance and explore in detail the sources
of thermal load originating from electrical and optical power. Optical power is found to have
a more critical impact on large area photoconductive emitter saturation than electrical power,
thus optimized heatsinking will allow us to improve the conversion efficiency in the near future
towards much higher emitter power. This work paves the way towards achieving hundreds of
MHz or even GHz repetition rates, high-power THz sources based on photoconductive emitters,
that are of great interest for example for future THz imaging applications.

Analysis, optimization and uncertainty quantification of the aerodynamic behaviour of turbomachinery components is a fundamental part of the current industrial design process and requires the extensive use of compute-intensive CFD simulations. In this paper we investigate whether graph neural networks can be useful as surrogate models to accelerate the design process, for example in a multi-fidelity framework. Graph neural networks promise to provide good estimates of flow quantities while maintaining the geometric accuracy at a fraction of the computational effort of classical CFD. An application to industrially relevant turbomachinery flows is performed to gain a good understanding of the capabilities and limitations of such methods. We therefore apply a state-of-the-art graph neural network to a turbomachinery setup of industry-relevant mesh size. In particular, a multiscale graph neural network is used to overcome the problems of large information distances when applying message-passing based graph-net blocks to large meshes. The database used to train the network consists of a space-filling DoE of 100 CFD solutions with different geometries. The first use case encompasses the prediction of the flow quantities of the complete fluid domain with 2.5e6 mesh points. The second use case focuses on predicting a single scalar (e.g. pressure or temperature) on surface meshes with up to 30e3 mesh points. In both cases, the networks are employed to predict time-averaged and unsteady flow fields on unstructured meshes of variable point sizes for new geometries not present in the training set. The results demonstrate the proficiency of the approach in predicting time-averaged and unsteady flow quantities on surfaces as well as for full fluid domains for new geometries.

Microfluidic technology, especially the droplet-based format, redefined biochemical methods, enhancing detection efficiency, reducing material consumption, and enabling real-time tracking of reactors, with applications spanning biology, biotechnology, and clinical diagnosis. Gaining insight into the dynamic fluctuations of biomarker levels in patients over time holds significant value for health tracking and postoperative diagnostics, as biomarkers serve as measurable indicators providing information within an organism. For instance, α-amylase levels in drainage fluid diagnose complications, but current methods delay adjustments due to only testing on the first and third day after the operation. Our strategy employs a portable device merging droplet-based microfluidic reactors and an optical biosensor for continuous α-amylase monitoring. This enables real-time detection, notably enhances sensitivity, minimizes fluid and reagent usage, and conserves resources.
The device's adjustability allows the detection of other enzymes and metabolism products, such as lipase, lactate, etc. For example, we used our portable device to monitor the lactate concentration in animal trials, with promising results correlating well with clinical blood measurements. In our lab, we also gelation the droplet reactors as 3D cancer cell models for T cell therapy. We expect to use our innovative droplet-based reactors in broader applications in clinical diagnosis for enabling personalized clinical treatment.

Biomarkers play an important role in early detection and prognosis; evaluating and monitoring their levels can indicate various clinical conditions of diseases (e.g., cancer and metabolic disorders).1 However, the traditional diagnostic methods often involve time-consuming laboratory assays, delaying clinical decisions. In recent years, there has been a growing interest in developing portable point-of-care diagnostic tools for rapid and accurate detecting of biomarkers.2 However, these biomolecular tests mainly focus on detecting biomolecules intermittently, lacking real-time and continuous monitoring. In our group, we present a novel portable droplet-based microfluidic system, combined with optical sensors, for the real-time continuous and long-term monitoring of biomarker (amylase or lactate) levels. Based on encapsulating samples within discrete droplets, our platform integrates sample acquisition, enzymatic assays, and optical detection, enabling real-time monitoring of biomarker concentrations with minimal sample volumes, reagent dose, and processing time. Moreover, our approach can analyze diverse clinical samples, including blood, interstitial fluids, and drain liquid with high sensitivity, selectivity, and accuracy. In previous work, we have achieved real-time sensing of drain α-amylase activity of patients undergoing pancreatic surgery with a bedside portable droplet-based millifluidic device.3 This strategy significantly improves the determination time (3 min), the detection limit of 7 nmol/s·L, and minimal material requirement (ca. 10 μL) and wastes. In the latest work, the portable droplet-based strategy performed well in accurately tracking lactate levels in the blood and interstitial liquid during animal trials, which aims to locally monitor lactate levels to indicate tissue blood perfusions during skin graft surgery. In summary, the droplet-based platform used in biomarkers monitoring brings a big potential in medical diagnosis, disease monitoring, peri-, and postoperative monitoring, and metabolism tracking during exercise.
1 S. Qiuet al, Signal Transduction and Targeted Therapy 8.1 (2023): 132.
2. A. Natalia et al., Nature Reviews Bioengineering 1.7 (2023): 481-498.
3. X. Zhao et al., Biosensors and Bioelectronics 251 (2024): 116034.

Copper nanowires (Cu NWs) are popular potential building blocks of various interconnecting components, microscale circuits, and nanoelectronics. Making interconnects at the nanoscale is still an open problem, and various methods have been explored during the past decades. While ion beam joining has been known for quite some time, the beam parameter-dependent processes leading to joining is yet to be understood in detail. A low-energy (5 keV) and broad argon ion beam is unable to induce joining among the Cu NW mesh, at the low ion currents (<400 nA). However, when the ion current was elevated to 1 µA at the same energy, a large-scale joining was observed. We developed a 3D finite volume model for heat transfer and Joule heating-based melting, which successfully explains the ion current-induced joining. When the current is increased to a significantly high level, the network fragments into smaller copper nanoparticles due to the heat produced. On the other hand, at higher argon ion energy (200 keV) a large-scale joining is observed even at small (<400 nA) beam current. A state-of-the-art, Monte Carlo-based TRI3DYN simulation predicted the role of recoils, redeposition, and ion beam mixing in such joining process at high ion energy, which is mostly due to elastic collisional consequences. Such ion current-induced nanowelded copper mesh-coated PET substrate shows good transmission in the optical range of wavelengths and a notable decrease in the sheet resistance is observed.

Online monitoring of the froth phase in flotation processes has considerable potential for optimization because its properties, such as froth height, are closely related to product quality. Since the insertion of a probe is often not feasible, measuring the froth height from above could be a simple, contactless possibility to capture the height over a large area of the froth surface. To evaluate the applicability of laser-based techniques for height measurements in foam and froth experiments, we tested a lidar sensor and laser triangulation using an industrial laser line scanner. Both techniques proved to be generally suitable for foam and froth height measurement. Investigating the measurement uncertainties, we found that the height of rising and overflowing foam is systematically underestimated. Additionally, the experiments revealed that the sensors can be used to detect changes in foam properties such as the liquid fraction or foam stability.

The new generation of satellite hyperspectral (HS) sensors provides remarkable potential  for  regional-scale  mineralogical  mapping.  However,  as  with  any  satellite  sensor,  mapping  results  are  dependent  on  a  typically  complex  correction  procedure  needed  to  remove  atmospheric,  topographic  and  geometric  distortions  before  accurate  reflectance  spectra  can  be  retrieved.  These  are  typically applied by the satellite operators but use different approaches that can yield different results. In this study, we conduct a comparative analysis of PRISMA, EnMAP, and EMIT hyperspectral  satellite  data,  alongside  airborne  data  acquired  by  the  HyMap  sensor,  to  investigate  the  consistency between these datasets and their suitability for geological mapping. Two sites in Namibia  were selected for this comparison, the Marinkas-Quellen and Epembe carbonatite complexes, based  on their geological significance, relatively good exposure, arid climate and data availability. We conducted qualitative and three different quantitative comparisons of the hyperspectral data from these  sites.  These  included  correlative  comparisons  of  (1)  the  reflectance  values  across  the  visible-near  infrared (VNIR) to shortwave infrared (SWIR) spectral ranges, (2) established spectral indices sensitive to minerals we expect in each of the scenes, and (3) spectral abundances estimated using linear  unmixing. The results highlighted a notable shift in inter-sensor consistency between the VNIR and  SWIR spectral ranges, with the VNIR range being more similar between the compared sensors than  the SWIR. Our qualitative comparisons suggest that the SWIR spectra from the EnMAP and EMIT  sensors are the most interpretable (show the most distinct absorption features) but that latent features (i.e., endmember abundances) from the HyMap and PRISMA sensors are consistent with geological  variations.  We conclude  that  our  results  reinforce  the  need  for  accurate  radiometric  and  topographic  corrections,  especially  for  the  SWIR  range  most  commonly  used  for  geological  mapping.

Plant growth on mine wastes is restricted by the lack of water, nutrients, phytotoxic responses and
the absence of a seedbank. In a mesocosm study, we addressed the establishment of vegetation
on metalliferous mine wastes from two seed mixtures. Besides the composition of the vegetation
and the increase in plant cover and biomass over time, we studied concentrations of heavy metals
in the shoot and analyzed the quantity of throughflow, its pH and EC to follow pollutant discharge.
We hypothesized that the types of mine wastes and sown grasslands will affect species composition
and the formation of a protective plant cover. Our platform was well-suited to study build-up and
succession of a vegetation layer and its potential to stabilize mine wastes. However, the establishing
community was less diverse than expected. The dilution of wastes increased species number and
biomass, and we found a reduction of material discharge with increasing vegetation cover. Over
time, drainage was reduced, while pH of the throughflow did not change. However, it was higher
under the addition of greywater. Interestingly, the use of greywater led to a higher biomass in one
mixture and slight changes in the chemistry of the throughflow and the plant matter.

Two series of Th1-xZrxSiO4 phases were synthesized hydrothermally under weakly basic (pH = 8) and strongly acidic (pH = 1) conditions. Changes in pH were found to have a significant effect on experimental phase diagrams. Synthesis at pH = 8 favors the formation of Th-rich phases with resulting Th1-xZrxSiO4 solid solution for x = 0 – 0.5. Contrary, synthesis at pH = 1 results in the formation of pure end-members of the ThSiO4-ZrSiO4 pseudo-binary system separated by multiple miscibility gaps. Phases formed both under basic and acidic conditions were found to retain water, which can be discharged from the structure upon heating. A different high-pressure (HP) behaviour was found for Th-rich and Zr-rich solid solutions. While Th-rich Th0.9Zr0.1SiO4 and Th0.6Zr0.4SiO4 phases retain their stoichiometry and crystal structure upon compression at HP, a significant reduction of the Th occupancy related to a decrease of the Th-O distances is observed for the Th-poor Th0.26Zr0.74SiO4 phase at P > 8 GPa, with the subsequent formation of a Th-rich amorphous phase. The Th diffusion between the crystalline and amorphous phases was found to be fully reversible. This unique self-healing property makes these phases promising candidates for nuclear applications under extreme pressure and temperature conditions, in particular those found in underground repositories.

The dataset consists of Infrared photodissociation (IRPD) spectra of Cu+(H2O)(H2)n (with n ≤ 3) and its isotopologue measured on the Leipzig 5 K ring-electrode ion-trap triple mass spectrometer. Besides, it contains the Energy Decomposition Analysis (EDA), the benchmark results, the harmonic and the anharmonic VPT2 frequencies results as well as the script used to get the predicted separation factor for the adsorbed dihydrogen isotopologue.

Little is known about the strong mediating effect of the ligand sphere and the coordination geometry on the strength and isotopologue selectivity of hydrogen adsorption on the undercoordinated copper(I) site. Here, we explore this effect using gas-phase complexes Cu+(H2O)(H2)n (with n ≤ 3) as model systems. Cu+(H2O) attracts dihydrogen (82 kJ mol−1) more strongly than bare Cu+ (64 kJ mol−1) does. Combining experimental and computational methods, we demonstrate a high isotopologue selectivity in dihydrogen binding to Cu+(H2O), which results from a large difference in the adsorption zero-point energies (2.8 kJ mol−1 between D2 and H2, including an anharmonic contribution of 0.4 kJ mol−1). We investigate its origins and the bond strengthening between Cu+ and H2 upon addition of a single H2O ligand. We discuss the role of the environment and the coordination geometry of the adsorption site in achieving a high selectivity and the ramifications for identifying and designing future materials for adsorptive dihydrogen isotopologue separation.

Langevin dynamics simulations are used to analyze the static and dynamic properties of an XY model adapted to dimers forming on Si(001) surfaces. The numerics utilise high-performance parallel computation methods on GPUs. The static exponent ν of the symmetry-broken XY model is determined to ν=1.04. The dynamic critical exponent z is determined to z=2.13 and, together with ν, shows the behavior of the Ising universality class. For time-dependent temperatures, we observe frozen domains and compare their size distribution with predictions from Kibble-Zurek theory. We determine a significantly larger quench exponent that shows little dependence on the damping or the symmetry-breaking field.

The Helmholtz project FINEST addresses challenges in the fields of circular economy, recycling and sustainable resources. Part of this work involves the mixing of fine particles to recycle those materials, which cannot be separated further. The work includes Modelling of Powder Mixing and Segregation. Additionally, the process is studied using Microfocus X-Ray CT (μCT).
Industrial processes are inevitably associated with generating fine-grained particulate matter. Such fine-grained residues rarely find re-entry into industrial value chains; typically, they are disposed and become an environmental burden. Prominent examples are dusts from mineral processing, degraded end-
of-life fibers, or micro plastic entering the natural environment. FINEST will process different residues in an optimized manner to generate value and to minimize hazards. Economic and ecological assessment of waste management concepts provides opportunities to create value by decreased disposal costs. Associated institutions provide the capability to transfer FINEST results to the relevant industrial sectors and potential consumers. The appendant Research School educates a next generation of experts for leadership positions in industry and academia.
In powder mixing, segregation is caused by differences in particle properties. In the context of FINEST, it is by their different density, because the particles range from plastics to metals. We choose a noninvasive technique to investigate the process. Particles from 150 – 250 μm with densities between 0.5 – 5 g/cm³ are mixed in a cylindrical bladed mixer. The μCT scans of powder mixtures are acquired with voxel size of 100 μm. Using a 3D analysis method, the quality of mixture is described by a variance measure. We present the method on a few sample measurements. It describes the evolution of mixing quality over time.
Continuum modelling is chosen to simulate the mixing studied experimentally before. Discrete methods would reach their computational limits. Continuum models of powder mixing in a bladed mixer were given e.g. by Yang et al. (2022). They include size-segregation. Density driven segregation was covered in a continuum model of an annular shear cell (Tirapelle et al, 2021). We combine those approaches. First step was to implement our Finite Volume Model in OpenFOAM. It is an Eulerian model, featuring a transport equation with advection, diffusion and segregation term. Flow behavior of powders is described by μ(I)-rheology.

The recycling of fine-grained residues from various industrial sources poses challenges in terms of their processing. One processing step is the mixing of fine particles. When mixing powders, segregation can occur due to differences in particle properties. As part of a national consortium project, we are investigating the behaviour of powders with different densities, which is relevant when e.g. plastics and metals from shredding are processed together. For our study we used a non-invasive technique to investigate the mixing process: Microfocus X-ray Computed Tomography (μCT).
Particles from 150 - 250 μm with densities between 0.5 - 5 g/cm³ are mixed in a cylindrical bladed mixer. The μCT scans of the powder mixtures are taken with a voxel size of 100 μm. Using a 3D analysis method, the quality of the mixture is described by a variance measure. We discuss the method for selected experiments. It can be used to describe the evolution of mixture quality over time. When applied to a variety of mixtures, the method can be used to investigate the effects of different parameters such as mixing speed, density ratio and mixing time. This will reveal their contribution to segregation and the dependence of the variance measure (representing mixing quality).

The connection between metadata, data, and software and the integration in an overall lifecycle is crucial for effective data management in research. The generic data management lifecycle, developed at HZDR, bridges these critical components, ensuring seamless data discovery, accessibility, and reproducibility. The approach emphasises the planning of experiments, the role of metadata, data storage, as well as software versioning, and the final publication of digital research artefacts, which enables comprehensive traceability from data creation to long-term archiving. By aligning these elements in a unified procedure, we recommend a uniform lifecycle that can be adapted to different research areas, with a particular focus on photon science and community services such as SciCat that improve data integrity and promote collaborative research.

The textures of the β- and α-phases of the metastable β-titanium alloy Ti5321 after hot
deformation were investigated by neutron diffraction. A hot-rolled bar was solutionized in the
β-phase field and then hot compressed above and below the β-transus temperature. The initial texture
after full recrystallization and grain growth in the β-phase field exhibits a weak cube component
{001}<100> and minor {112}<110> and {111}<110> components. After hot compression, a <100> fiber
texture is observed, increasing in intensity with compression temperature. Below the β-transus
temperature, dynamic recrystallization of the β-phase and dynamic spheroidization of the α-phase
interact strongly. The texture of the α-phase is a <11–20> fiber texture, increasing in intensity with
decreasing compression temperature. The mechanisms of texture formation during hot compression
are discussed.

Ziel dieser Masterarbeit ist es, neue Chelatliganden für radiometallische Alphastrahler und deren diagnostischen Pendants zu synthetisieren und zu charakterisieren. Diese sollen anschließend auf ihre Fähigkeit zur Radiomarkierung mit unterschiedlichen Radionukliden untersucht und erste Aussagen zur Komplexstabilität getroffen werden. Von besonderem Interesse für die therapeutische Anwendung sind dabei die Radionuklide 223/224Ra, 225Ac (Alphastrahler) und 212Pb (Betastrahler mit Alphaanteil in der Zerfallsreihe). Aufgrund des theranostischen Konzepts sind die diagnostischen Radiometallnuklide 131Ba, 133La, und 203Pb ebenfalls von Interesse.
Als Ausgangsverbindung dient der literaturbekannte Makrozyklus Tetraaza-18-krone-6. Dieser soll mit Polyethylenglycolen überbrückt und mit Picolinaten als Seitenarmen funktionalisiert werden. Es soll eine eigene Syntheseroute, ausgehend von der Startverbindung 2,2'-Oxybis(ethylamin) entwickelt werden, um eine regioselektive Synthese und unterschiedliche Funktionalisierung der Zielverbindungen zu ermöglichen. Die Funktionalisierung sollte mit
unterschiedlich langen Überbrückungen realisiert werden und auch in den alternierenden Positionen der Funktionalisierungen. Die Synthesen der in Abbildung 6 gezeigten Zielverbindungen werden angestrebt.

Macropa-PSMA-ligand conjugates used for targeted alpha-therapy (TAT) with actinium-225 were furnished with an albumin binder to improve their pharmacological behaviour in vivo. [1,2] Additionally, the introduction of an iodine-containing albumin binder provides the basis for the development of a novel theranostic radioconjugate pair using the radiohybrid approach. This involves the complexation of the alpha emitter actinium-225 (half-life: 9.9 d) and the introduction of the easily accessible SPECT-compatible radiohalogen iodine-123 into the same molecule. Advantageously, its ideal physical half-life of 13.2 h and mild radioiodination conditions allows the imaging of longer circulating radioconjugates. The PSMA-binding motif based on the PSMA-617 structure was prepared by a multi-step peptide synthesis followed by subsequent conjugation with the macropa chelator by Cu-catalysed azide-alkyne (CuAAC) click chemistry. The labelling precursor for the introduction of iodine-123 was synthesized by replacing the 4-(p-iodophenyl)butyrate by a trimethylstannyl group to enable labelling by electrophilic aromatic substitution reaction. To determine the binding affinity, LNCaP cells were incubated with the nonradioactive conjugates (with and without nonradioactive lanthanum (La) as congener for actinium-225) in a competition assay and spiked with the radioconjugate [133La]La-PSMA-617. The influence of the complexing agent and the metal ion loading on the binding affinity was evaluated. Two radioconjugates were developed: [123I]I-mcp-M-alb-PSMA with one PSMA-binding motif was prepared from the stannyl precursor (DMSO, Iodogen, 20 min, rt, RCY: 49%) and [123I]I-mcp-D-alb-PSMA with two PSMA-binding motifs was labelled under the same conditions with the exception of adding nonradioactive iodine after completion of radiolabelling to iodinate the second stannyl group (RCY: 20%). Both radioconjugates were purified by HPLC. Beneficially, no influence of chelator loading on cell binding was observed in vitro. The cell binding is comparable across the analogues (mcp-M-alb-PSMA: Ki = 8.46 nM (7.05 - 10.14), La-mcp-M-alb-PSMA: Ki = 8.46 nM (6.72 - 10.66) / mcp-D-alb-PSMA: Ki = 2.35 nM (2.03 - 2.71), La-mcp-D-alb-PSMA: Ki = 2.21 nM (1.64 - 2.96)). Preliminary small animal SPECT imaging with tumor-bearing mice was executed pointing out a biodistribution of [123I]I-mcp-M-alb-PSMA which is comparable to [225Ac]Ac-mcp-M-alb-PSMA. The synthesis of the tin precursors and subsequent radiolabelling with iodine-123 provided two new radioconjugates which act as diagnostic counterparts to the corresponding actinium-225 radioconjugates. The introduction of iodine-123, with or without metal ion loading of the macropa chelator, did not alter the PSMA binding affinity in vitro. The addition of the albumin binding domain opens up a new approach to use iodine-123 in combination with actinium-225 as new radiohybrid pair for the development of hybrid radiopharmaceuticals within the theranostic concept.