We present a development of the beam-tracking approach that allows its implementation in computed tomography. One absorbing mask placed before the sample and a high resolution detector are used to track variations in the beam intensity distribution caused by the sample. Absorption, refraction, and dark-field are retrieved through a multi-Gaussian interpolation of the beam. Standard filtered back projection is used to reconstruct three dimensional maps of the real and imaginary part of the refractive index, and of the dark-field signal. While the method is here demonstrated using synchrotron radiation, its low coherence requirements suggest a possible implementation with laboratory sources.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4635357 | PMC |
http://dx.doi.org/10.1038/srep16318 | DOI Listing |
Chemistry
January 2025
University of Windsor Faculty of Science, Chemistry & Biochemsitry, 401 Sunset Avenue, N9B 3P4, Windsor, CANADA.
Attachment of three different heterocycles with electron donor or acceptor character to a central 1,3,5-triazine core generates readily soluble side-chain free dyes with two displaying soft crystalline mesomorphism and one displaying a nematic liquid crystal phase as confirmed by polarized optical microscopy, calorimetry, gravimetric analysis, and powder X-ray diffraction. Equally intriguing is the dyes' relatively strong electronic communication between donor and acceptor subchromophores that are meta-conjugated to one another, which is experimentally observed as a broad intramolecular charge-transfer absorption that can extend over 100 nm past the most intense absorption event and is computationally confirmed through density functional theory (DFT) evaluations of the molecular ground- and excited-state properties. This molecular design permits the preparation of dyes with panchromatic absorption not just based on the additive absorption of individual subchromophores.
View Article and Find Full Text PDFChemistry
January 2025
Indian Institute of Technology Delhi, Department of Chemistry, Hauz Khas, 110016, New Delhi, INDIA.
A mononuclear CoIII complex (1) of a bisamide-bisalkoxide donor ligand was synthesized and thoroughly characterized. The reaction of 1 with 0.5 equiv.
View Article and Find Full Text PDFJ Phys Chem C Nanomater Interfaces
January 2025
Technical University of Munich, TUM School of Natural Sciences, Physics Department E20, Garching 85748, Germany.
Metalloporphyrins on interfaces offer a rich playground for functional materials and hence have been subjected to intense scrutiny over the past decades. As the same porphyrin macrocycle on the same surface may exhibit vastly different physicochemical properties depending on the metal center and its substituents, it is vital to have a thorough structural and chemical characterization of such systems. Here, we explore the distinctions arising from coverage and macrocycle substituents on the closely related ruthenium octaethyl porphyrin and ruthenium tetrabenzo porphyrin on Ag(111).
View Article and Find Full Text PDFHeliyon
January 2025
Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 51452, Saudi Arabia.
Purpose: Due to the extensive use of radiation in various fields, such as food safety, sterilizing surgical materials, and medical diagnostics, it is essential to minimize radiation exposure for both patients and healthcare professionals, even at low doses. To meet this requirement, a composite film has been developed using polyvinyl alcohol (PVA) polymer and nitro blue tetrazolium (NBT) dye to measure low radiation doses effectively.
Methods: Various concentrations of NBT dye (ranging from 0.
J Phys Chem A
January 2025
Institute of high energy physics, Chinese academy of sciences, Beijing 100049, China.
The determination of three-dimensional structures (3D structures) is crucial for understanding the correlation between the structural attributes of materials and their functional performance. X-ray absorption near edge structure (XANES) is an indispensable tool to characterize the atomic-scale local 3D structure of the system. Here, we present an approach to simulate XANES based on a customized 3D graph neural network (3DGNN) model, XAS3Dabs, which takes directly the 3D structure of the system as input, and the inherent relation between the fine structure of spectrum and local geometry is considered during the model construction.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!