Three representative oxides of the La(2/3)(-)(x)()Li(3)(x)()TiO(3) system have been studied by selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM), and powder synchrotron X-ray diffraction. HRTEM showed that the materials have a complex microstructure. The SAED and HRTEM results have allowed us to propose a model to refine the crystal structure of these oxides that also accounts for their microstructure. The materials have a perovskite-related structure with a diagonal unit cell ( radical 2a(p) x radical 2a(p) x 2a(p)) as a consequence of the tilting of the TiO(6) octahedra. Ordering of lanthanum and lithium ions and vacancies along the 2a(p)-axis, as well as displacements of titanium ions from the center of the octahedra, have been determined. The size and shape of the domains have been obtained from the synchrotron X-ray diffraction data; in addition, other extended defects such as strains and compositional fluctuations have been detected.
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http://dx.doi.org/10.1021/ja038410l | DOI Listing |
Synchrotron X-ray microtomography (S-µCT) is a highly valuable technique for investigating organ function and pathologies. However, its application is often limited by high radiation doses and the occurrence of ring artifacts. While S-µCT utilizing sparse-view projections can effectively decrease radiation doses, the reconstructed images frequently exhibit severe streaking artifacts, which are exacerbated by ring artifacts, ultimately compromising reconstruction accuracy, image quality, and resolution.
View Article and Find Full Text PDFFourth-generation synchrotron sources promise an enormous increase in the spatial coherence of X-ray radiation. In the EUV to soft X-ray range, the spatial coherence could reach almost 100% in both the horizontal and vertical directions. Identifying and understanding potential sources of degradation in the spatial coherence of X-rays transported along the beamline is critical to enable optimal performance for the experiments at the beamlines.
View Article and Find Full Text PDFMed Phys
January 2025
Department of Physics and Astronomy, University of California - Irvine, Irvine, California, USA.
Background: K-edge subtraction (KES) imaging is a dual-energy imaging technique that enhances contrast by subtracting images taken with x-rays that are above and below the K-edge energy of a specified contrast agent. The resulting reconstruction spatially identifies where the contrast agent accumulates, even when obscured by complex and heterogeneous distributions of human tissue. This method is most successful when x-ray sources are quasimonoenergetic and tunable, conditions that have traditionally only been met at synchrotrons.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
State Key Laboratory of Physical Chemistry of Solid Surface, Fujian Key Laboratory of Surface and Interface Engineering for High Performance Materials, College of Materials, Xiamen University, Xiamen 361005, China.
Sluggish redox kinetics and dendrite growth perplex the fulfillment of efficient electrochemistry in lithium-sulfur (Li-S) batteries. The complicated sulfur phase transformation and sulfur/lithium diversity kinetics necessitate an all-inclusive approach in catalyst design. Herein, a compatible mediator with nanoscale-asymmetric-size configuration by integrating Co single atoms and defective CoTe (Co-CoTe@NHCF) is elaborately developed for regulating sulfur/lithium electrochemistry synchronously.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
Department of Physics, Lund University, BOX 118, Lund, 221 00, SWEDEN.
In recent years, studies of surfaces at more realistic conditions has advanced significantly, leading to an increased understanding of surface dynamics under reaction conditions. The development has mainly been due to the development of new experimental techniques or new experimental approaches. Techniques such as High Pressure Scanning Tunneling/Force Microscopy (HPSTM/HPAFM), Ambient Pressure X-ray Photo emission Spectroscopy (APXPS), Surface X-Ray Diffraction (SXRD), Polarization-Modulation InfraRed Reflection Absorption Spectroscopy (PMIRRAS) and Planar Laser Induced Fluorescence (PLIF) at semi-realistic conditions has been used to study planar model catalysts or industrial materials under operating conditions.
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