An optical design study of a beamline proposed for the new 6 GeV synchrotron, the High Energy Photon Source (HEPS), to be built in Beijing, China, is described. The beamline is designed to cover an energy range from 0.5 to 11 keV with two experimental stations, one for X-ray photoelectron spectroscopy (PES) experiments and the other for photoelectron emission microscopy (XPEEM) experiments. A 5 m APPLE II-type undulator with a relatively long magnetic period (55 mm) is used as the only radiation source. To optimize the optical efficiency for the full energy range, the beamline is split into a soft X-ray branch that is based on a variable-line-spacing plane-grating monochromator and a tender X-ray branch that uses a four-bounce monochromator with three Si channel-cut pairs. To allow both PES and XPEEM to be performed over the entire energy range, two toroidal mirrors and a bendable KB mirror pair are employed to deliver the soft and tender beams, respectively, to either of two experimental stations.
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http://dx.doi.org/10.1107/S1600577519000523 | DOI Listing |
Angew Chem Int Ed Engl
December 2024
University of Chicago Division of the Physical Sciences, Chemistry, 929 E 57th St, Gordon Center for Integrative Science, 60637, Chicago, UNITED STATES OF AMERICA.
Intrinsic structural and oxidic defects activate graphitic carbon electrodes towards electrochemical reactions underpinning energy conversion and storage technologies. Yet, these defects can also disrupt the long-range and periodic arrangement of carbon atoms, and thus the characterization of graphitic carbon electrodes necessitate in-situ atomistic differentiation of graphitic regions from mesoscopic bulk disorder. Here, we leverage the combined techniques of in-situ attenuated total reflectance infrared spectroscopy and first-principles calculations to reveal that graphitic carbon electrodes exhibit electric-field dependent infrared activity that is sensitive to the bulk mesoscopic intrinsic disorder.
View Article and Find Full Text PDFJACS Au
December 2024
SUNCAT Center for Interface Science and Catalysis, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, United States.
Establishing energy correlations among different metals can accelerate the discovery of efficient and cost-effective catalysts for complex reactions. Using a recently introduced coordination-based model, we can predict site-specific metal binding energies (Δ ) that can be used as a descriptor for chemical reactions. In this study, we have examined a range of metals including Ag, Au, Co, Cu, Ir, Ni, Os, Pd, Pt, Rh, and Ru and found linear correlations between predicted Δ and adsorption energies of CH and O (Δ and Δ ) at various coordination environments for all the considered metals.
View Article and Find Full Text PDFJACS Au
December 2024
Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269-3060, United States.
Red-light absorbing photoredox catalysts offer potential advantages for large-scale reactions, expanding the range of usable substrates and facilitating bio-orthogonal applications. While many red-light absorbing/emitting fluorophores have been developed recently, functional red-light absorbing photoredox catalysts are scarce. Many photoredox catalysts rely on long-lived triplet excited states (triplets), which can efficiently engage in single electron transfer (SET) reactions with substrates.
View Article and Find Full Text PDFChem Biomed Imaging
December 2024
Department of Chemistry "G.Ciamician", University of Bologna, UE4, Via. P. Gobetti 85, 40129 Bologna, Italy.
Electrochemiluminescence (ECL) is nowadays a powerful technique widely used in biosensing and imaging, offering high sensitivity and specificity for detecting and mapping biomolecules. Screen-printed electrodes (SPEs) offer a versatile and cost-effective platform for ECL applications due to their ease of fabrication, disposability, and suitability for large-scale production. This research introduces a novel method for improving the ECL characteristics of screen-printed carbon electrodes (SPCEs) through the application of CO laser treatment following fabrication.
View Article and Find Full Text PDFJ Med Imaging (Bellingham)
December 2024
University of Chicago, Department of Radiology, Chicago, Illinois, United States.
Purpose: High soft-tissue contrast imaging is essential for effective radiotherapy treatment. This could potentially be realized using both megavoltage and kilovoltage x-ray sources available on some therapy treatment systems to perform "MV-kV" dual-energy (DE) computed tomography (CT). However, noisy megavoltage images obtained with existing energy-integrating detectors (EIDs) are a limiting factor for clinical translation.
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