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Measurement of B meson production fraction ratios in proton-proton collisions at = 13 TeV using open-charm and charmonium decays
No full textProduction fraction ratios of B, B, and B mesons are measured in proton-proton collisions at = 13 TeV using a special data set recorded in 2018 with high-rate triggers designed to collect an unbiased sample of b hadrons with the CMS experiment at the LHC. These data allow the use of the open-charm decays of B mesons (BD) where the D meson decays into fully hadronic final states. Production fraction ratios as functions of B meson transverse momentum () and rapidity () are measured using the open-charm decays in the kinematic range of 8 60 GeV and 2.25. In addition, the same data are used to measure the relative production fraction ratios with the charmonium decay channels (B XJ/ with X indicating a K, K(892), or (1020) meson) with the J/ meson decaying into a pair of muons. By utilizing known branching fractions, precision theoretical calculations, and the open-charm results, the production fraction ratios in the charmonium samples are determined with an absolute normalization for the first time. These results also improve several world-average values of the ratios of branching fractions of B meson decays to charmonium and open-charm states. Finally, we test isospin invariance in B meson production in proton-proton collisions and observe that it holds within the experimental precision
Shaping low-iridium IrRuO electrocatalysts with structural and electronic modulation for proton exchange membrane electrolyzers
No full textReducing iridium (Ir) loading without compromising the stability of the oxygen evolution reaction (OER) activity is essential for the sustainable deployment of proton exchange membrane (PEM) electrolyzers. One promising approach is the development of Ir-based mixed oxides, such as Ir–Ru systems, which harness synergistic effects to enhance activity and durability beyond that of IrO benchmarks. Here, we report a unique high-performance IrRuO catalyst synthesized via a straightforward solid-state molten-salt method. Structural characterization employing both synchrotron and in-house XRD revealed lattice contraction in IrRuO relative to IrO/i>, which hinted a solid-solution formation. X-ray photoelectron spectroscopy confirmed higher oxidation states of Ru in IrRuO compared to RuO, which is correlated with its enhanced electrochemical performance. Electron microscopy studies showed the formation of 2D nanosheets rich in grain boundaries (GBs), which facilitate charge transport and stabilize active sites. Pair distribution function (PDF) analysis revealed the coexistence of rutile and hollandite phases, with hollandite content decreasing at higher synthesis temperatures and with increasing Ru content. As an anode in a proton exchange membrane electrolyzer, IrRuO demonstrated superior performance and delivered 1 A cm at 1.69 V with only ∼0.3 mg cm—outperforming commercial IrO (1.75 V) and IrRuO(1.77 V) under similar conditions
Nanoelectrospray ionization coupled to a linear charge detection array ion trap spectrometer for single viral particle analysis
No full textThis work presents the implementation of a new charge detection mass spectrometer (CDMS) design that operates in stand-alone mode, enabled by integration with nanoelectrospray ionization. More specifically, this innovative CDMS consists of a linear charge detection array ion trap spectrometer that combines an eight-tube detector array with conical electrodes. This configuration allows recording data in both transmission mode (linear array) and ion trapping mode (ConeArrayTrap) and measuring the time-of-flight (related to the mass-to-charge ratio) along with the charge of individual ions. Thus, this design supports the high-throughput metrology of viruses at the single-particle level. The devices and geometry of the instrument have been developed based on ion optics simulations. The performance of the current instrument is demonstrated using human norovirus-like particles (hNoVLP) and Adenovirus Ad(5) (hAdV5)
Response of InGaN/GaN multiple quantum well structure to UV-C and vacuum UV optical excitation
No full textWe report on the behavior of InGaN/GaN multiple quantum well structure during excitation in UV-C and vacuum UV spectral region. Photoluminescence excitationspectra show peaks with positions different to the peaks in absorption spectra. The very high absorption coefficient in order of 107 cm− 1 at energies above 6.9 eVcauses the excitation in the surface region which enhances the non-radiative surface recombination. The mechanism explains the differences between absorption andexcitation spectra measured in a studied range of energies between 5.8 and 40 eV
Numerical calculation and experimental validation of gas-accelerated flat sheet jet
No full textThis study presents the experimentally validated numerical simulation of a gas-accelerated flat sheetjet, providing valuable insights into its behaviour. The numerical calculation, based on the finite volumemethod (FVM) and volume of fluid (VOF) model, simulates a sheet jet with a gas Reynolds number of351, liquid Reynolds number of 332, Weber number of 51 and Capillary number of 0.15. A gridconvergence study confirmed that realistic behavior requires at least three computational non-adaptivecells (1.5 μm) across the radius of the sheet’s thinnest region (~5 μm), supplemented by at least twoadaptive mesh refinement (AMR) levels of the interface, giving a minimum cell size of 375 nm. Acomparison of various numerical cases for the analyzed multiphase, compressible, and unsteady flowrevealed that accuracy depends on grid resolution but is not sensitive to numerical schemes or settings.The developed numerical model demonstrates high accuracy, with the link area of the primary sheet(11,000 μm2) overestimated by 6%, the width (49.2 μm) by 6%, and the length (215 μm) underpredictedby 2%, all within the measurement uncertainty of 7%. The flow within the sheet jet was found to belaminar, without any recirculation zones.The analysis of the sheet jet dynamics identified four distinctflow regions governed by sheath gas pressure, surface tension and inertial forces, explaining theevolution of gas-accelerated flat sheet jets through successive orthogonal links forming a liquid chain
In situ GISAXS Study of Permalloy Thin Film Growth Dynamics on Self-organized Nanorippled Si Templates
No full textReal-time growth investigation of permalloy (Py) thin film deposition on ion beam sculptured nanoripple Si template has been performed using in situ grazing incidence small angle X-ray scattering (GISAXS) technique. During film deposition, four growth regimes are observed- Template-guided conformal growth transitions into strain-induced roughening, followed by structural reordering, and finally bulk-like rough film growth. The growth behavior of the film, including its shape and spatial arrangements, has been obtained using simulation and models. Anisotropic magnetoresistance (AMR) has been performed to study the magneto transport properties of the thickness dependence of Py films on nanorippled templates. As the film thickness increases, the effect of surface ripples on its magnetic behavior weakens, which reduces the AMR response
The biomechanical dilemma of phasmid eggs – how do stick insects hatch?
No full textDuring their development, phasmid eggs with their long developmental periods face numerous biotic and abiotic challenges. These insect eggs are unique for their thick egg capsule and a specialised escape structure called the operculum/lid. This operculum needs to be easy to open from the inside, yet must not be a ‘weak spot’ for potential predators. One possible solution to this biomechanical dilemma could be a change in the operculum's mechanical properties over time. To investigate this hypothesis, we analysed the effect of age and storage conditions on the biomechanical properties of the egg and the operculum. We also performed high-resolution X-ray microscopy (XRM) and synchrotron studies to analyse the ultrastructure of the eggshell and operculum. Our results show that the eggs of Carausius morosus were able to resist a compressive force of up to 2 N. During maturation, the force required to open the operculum was significantly reduced from 0.14 N to 0.09 N. The properties of the eggshell itself, however, were not affected by humidity and did not change during maturation. Interestingly, the egg properties were affected by the mother's age. Our results thus indicate that the operculum is not a primary fracture site for externally applied stress; however, structural changes in the operculum during the developmental process of the embryo facilitate the hatching process
KCl-Mediated Defect Passivation in Vapor-Deposited Perovskites
No full textPerovskite-based solar cells (PSCs) have reached efficiencies comparable to those of commonly used silicon solar panels. Despite the promise of PSCs, their efficiency and commercial viability are currently restricted by three main factors: nonradiative charge recombinations on defects occurring within the light-absorbing layer and at its boundaries, limited reproducibility, and upscaling due to widely employed wet deposition methods. To address these issues, we investigated the defect passivation strategy by introducing potassium salt (KCl) during perovskite vapor deposition. We observed effective passivation of the defects upon KCl addition, manifested as an immediate and significant enhancement of the real-time photoluminescence (PL) intensity. The efficiency of passivation is related to the ionic nature of the potassium salt and its flux density. On the other hand, the perovskite’s crystallographic structure and texture, as observed from the grazing-incidence wide/small-angle X-ray scattering measurements, showed no significant changes due to KCl doping. Our work provides valuable insight into the possible passivation routes for the vapor-deposited perovskite layers, with implications for various chemical compositions or architectures
Constraining the Extragalactic Magnetic Field: Auger Data Meet UHECR Propagation Modeling
No full textRecent analyses from the Pierre Auger Collaboration suggest correlations between the arrival directions of Ultra-High-Energy Cosmic Rays (UHECRs) and catalogs of starburst galaxies (SGBs) and jetted active galactic nuclei (AGNs). We revisit these analyses using the same methodology as \auger , but explicitly incorporating UHECR deflections in turbulent extragalactic magnetic fields (EGMFs). We demonstrate that while for SBGs the same sources as for the generic \auger\ analysis dominate the catalog correlations, jetted AGNs are dominated by Centaurus~A when accounting for source distances and deflections. Using our framework, we derive 90\% confidence level upper limits on the local EGMF strength of 4.4~nG~Mpc for SBGs and 6.7~nG~Mpc for jetted AGNs. Assuming instead that the UHECR deflections predominantly arise from the Galactic magnetic field (GMF), we obtain a GMF upper limit of G~kpc for a Galactic halo size of 30~kpc