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Interface Evolution and Long-Term Performance of Negative Carbon Fiber Structural Electrodes
No full textLaminated structural batteries present a transformativesolution to reducing weight constraints in electric vehicles. Thesestructural batteries are based on a multifunctional material thatincorporates an energy storage function within a carbon fiberreinforced polymer. Despite the potential of this technology, theintricate morphology of fiber−matrix or electrode−electrolyteinterfaces and the impact of long-term cycling at low current rates(C-rates) on these interfaces remain insufficiently understood. Thisstudy addresses these critical knowledge gaps by examining theinfluence of matrix composition on the long-term electrochemicalperformance of structural battery electrodes and exploring advancedtechniques to investigate carbon fiber−matrix interfaces. Localizedimaging and X-ray scattering techniques were used to characterizemorphological changes at the electrode−electrolyte interfaces by analyzing negative structural electrodes. The findings revealed thatthe matrix composition influences long-term electrochemical behavior and fiber−matrix interface formation. While the intrinsicproperties of carbon fibers largely remain unaffected by long-term cycling, cycling promotes debonding at fiber−matrix interfaces.Nonetheless, residual regions of adhesion persist, underscoring the potential for preserving multifunctionality even under prolongedcycling conditions. These insights advance the understanding of interface dynamics, which is critical for optimizing structural batterytechnologies
In Situ X-ray Phase Contrast Imaging of Humping Formation During Laser Beam Welding of 1.4404 Stainless Steel
No full textContinuous development of laser beam sources and process technologies allows higher welding speeds, partly due to the high focus ability and brilliance of fiber laser sources. However, the increasing interest in cost-efficient production of bipolar plates for fuel cells, for example, poses a challenge due to imperfections, which occur during high-speed welding of metals. A particular defect – referred to as humping in the welding sector – manifests itself in the form of periodical accumulation of solidified melt on the weld bead surface. The main objective of this paper is to establish a basic under- standing of humping, which could allow a shift of the effect to higher welding speeds for stainless steel 316L. This is done through tests using in-situ X-ray videographic images. Factors of capillary dynamics and capillary behavior that cause humping are analyzed. Furthermore, attempts to shift the humping limit are investigated using an Adjustable Ring Mode (ARM) laser. With the flexible power control of the core to ring beam, the capillary dynamics and the occurrence of humping are closely examined. Finally, new findings with regards to the indicators for the occurrence of humping and anssessment of the use of an ARM laser to avoid humping are deduced.Keywords: laser welding, stainless steel, humping, welding speed, keyhole dynamics, vapor capillary, X-ray imagin
X-ray transition radiation by high-energy electrons in a thin solid target placed in an external magnetic field
No full textX-ray transition radiation emitted by high-energy electrons in a thin foil placed in a strong external magnetic field is considered. The modification of the radiation properties resulting from the bending of the particle’s trajectory in the magnetic field is investigated. It is shown that, due to the interference between transition and synchrotron radiation, the total radiation spectrum can significantly differ from the simple sum of the conventional spectra of these two types of emission. Both constructive and destructive interference can occur in this case. The dependence of the magnitude of this interference on the electron energy and the acceptance angle of the radiation detector is analyzed
Non-Standard Neutrino Interactions at a Muon Collider Neutrino Detector
No full textIn addition to their broad physics reach enabled by their high energies and precision, future multi-TeV muon colliders will also be the world's most intense sources of neutrinos. This offers the opportunity to search for new non-standard neutrino interactions, possible by installing a dedicated forward neutrino detector in the straight sections of the collision ring, which is then used to measure reactions initiated by neutrinos from the decaying beam muons. In this paper, we show that these searches can exceed current and upcoming bounds on non-standard neutrino interactions from low-energy precision experiments and the LHC. This is achieved by the large flux of high-energetic neutrinos, the precise knowledge of the neutrino flavor composition on each side of the interaction point and the chirality of the neutrinos. We further discuss the technical requirements of the proposed forward neutrino detector, \FASERmuC, to maximally exploit this physics potential
Efficient optical coating design using an autoencoder-based neural network model
No full textOptical thin-film coatings are integral to modern photonics and in particular to ultrafastlasers, providing precise control of dispersion and reflectivity, thus enabling tailored pulseshaping. Designing these coatings represents an inverse problem, requiring the mapping ofdesired optical properties to physical designs, a task that poses major challenges fortraditional heuristic methods, which are time-consuming and often sub-optimal. Here, wepresent an artificial intelligence (AI) framework for optical thin-film coating design thataccelerates the design process, achieving excellent performance characteristics withoutexpert intervention. We discuss our AI approach and demonstrate the capabilities of ouralgorithm by designing a complex broadband high-reflectivity mirror with state-of-the-artperformance characteristics including a −200 fs2 group delay dispersion covering a spectralrange of 940 nm to 1120 nm
Room-temperature X-ray fragment screening with serial crystallography
No full textStructural insights into protein-ligand interactions are essential for advancing drug development, with macromolecular X-ray crystallography being a cornerstone technique. Commonly X-ray data collection is conducted at cryogenic temperatures to mitigate radiation damage effects. However, this can introduce artifacts not only in the protein conformation but also in protein-ligand interactions. Recent studies highlight the advantages of room-temperature (RT) crystallography in capturing relevant states much closer to physiological temperatures. We have advanced fixed-target serial crystallography to enable high-throughput fragment screening at RT. Here we systematically compare RT fragment screening with conventional single crystal data collection at cryogenic temperature (cryo) of the Fosfomycin-resistance protein A from Klebsiella pneumoniae (FosAKP), an enzyme involved in antibiotic resistance. With RT serial crystallography we achieve resolutions comparable to cryogenic methods and identify a previously unobserved conformational state of the active site, offering additional starting points for drug design. For ligands identified in both screens, temperature did not have an influence on the binding mode of the ligand. But overall, we observed more binders at cryo, both at physiologically relevant and non-relevant sites. With the potential for further automation, RT screening with serial crystallography can advance drug development pipelines by making new conformations of proteins accessible
Suppressed Degradation Process of PBDB-TF-T1:BTP-4F-12-Based Organic Solar Cells with Solid Additive Atums Green
No full textSolid additives have garnered significant attention due to their numerous advantages over liquid additives. This study explores the potential of the green-fluorescent conjugated polymer denoted Atums Green as a solid additive in green-solvent-based PBDB-TF-T1:BTP-4F-12 solar cells. Even tiny amounts of Atums Green doping significantly improve the device performance. For the reference solar cell without any additive, we find that device degradation is not caused by chemical redox reactions but by changes in crystallinity and microstructure evolution during aging in air under illumination. Operando GIWAXS and GISAXS are used to investigate the structure evolution. We discover a four-stage degradation process for the reference cell. In general, the lattice spacing and crystallite coherence length decrease, while the domain sizes increase, which causes the loss of shirt-circuit current J and fill factor FF. Furthermore, a decomposition component is detected in GIWAXS and GISAXS, corresponding to the loss of the open-circuit voltage V. Atums Green doping effectively suppresses the evolution of crystallinity and domain sizes as well as the continuous decomposition, thereby enhancing the device stability under illumination in air. This finding reveals the kinetic degradation process of organic solar cells, establishes a correlation between the morphological properties and device performance, and further demonstrates the promising potential of Atums Green doping in organic solar cells
MagStREXS, a crystallographic software to study magnetic structures through Resonant Elastic X-ray Scattering data: 1. Fundamental equations
No full textResonant elastic X-ray scattering (REXS) is an experimental technique that can be highly valuable for studying magnetic structures in certain scenarios. In this paper, we introduce MagStREXS, a crystallographic program designed to determine magnetic structures from REXS data. This software makes use of the key concepts and computational tools already established in the field of magnetic crystallography. Here, we present the fundamental equations implemented in MagStREXS, derived for the two methods used to describe magnetic models: the representation analysis and the symmetry-based approach. We illustrate the capabilities of MagStREXS with a case study. The software is under active development, with the aim of benefiting both specialists and non-specialists in the field.Keywords: resonant X-ray magnetic scattering; REXS; magnetic structures; computer programs
Search for dark matter production in association with a single top quark in proton-proton collisions at = 13 TeV
No full textA search for the production of a single top quark in association with invisible particles is performed using proton-proton collision data collected with the CMS detector at the LHC at TeV, corresponding to an integrated luminosity of 138 fb. In this search, a flavor-changing neutral current produces a single top quark or antiquark and an invisible state nonresonantly. The invisible state consists of a hypothetical spin-1 particle acting as a new mediator and decaying to two spin-1/2 dark matter candidates. The analysis searches for events in which the top quark or antiquark decays hadronically. No significant excess of events compatible with that signature is observed. Exclusion limits at 95% confidence level are placed on the masses of the spin-1 mediator and the dark matter candidates, and are compared to constraints from the dark matter relic density measurements. In a vector (axial-vector) coupling scenario, masses of the spin-1 mediator are excluded up to 1.85 (1.85) TeV with an expectation of 2.0 (2.0) TeV, whereas masses of the dark matter candidates are excluded up to 0.75 (0.55) TeV with an expectation of 0.85 (0.65) TeV.[graphic not available: see fulltext
Simplistic Software for Analyzing Mass Spectra and a Mixed Experimental‐Theoretical Database for Identifying Poisonous and Explosive Substances
No full textA recent increase in targeted attacks using chemical warfare agents by dictators and authoritarian regimes against politicians,journalists, and other civilians is a major concern. To aid the civil investigators in identifying poisonous substances in such cases,we developed an algorithm and a lightweight and simple-to-use software, , with a database of 400 electronionization mass spectra entries, which include many poisonous and explosive agents. The identification relies on a window-basedreduction of the experimental spectra and four statistical metrics that are combined into a single metametric. The software alsofeatures automatic spectral background removal. Furthermore, we provide the workflow for increasing the size of this databaseby performing theoretical calculations of mass spectra with a molecular dynamics-based approach. The accuracy of both thetheoretical prediction workflow and is validated on the experimental spectra. Our results demonstrate thatthe proposed software package can aid in the preliminary identification of traces of poisonous and explosive substances