The evolution of bismuth crystal structure upon excitation of its A phonon has been intensely studied with short pulse optical lasers. Here we present the first-time observation of a hard x-ray induced ultrafast phase transition in a bismuth single crystal at high intensities (~10 W/cm). The lattice evolution was followed using a recently demonstrated x-ray single-shot probing setup. The time evolution of the (111) Bragg peak intensity showed strong dependence on the excitation fluence. After exposure to a sufficiently intense x-ray pulse, the peak intensity dropped to zero within 300 fs, i.e. faster than one oscillation period of the A mode at room temperature. Our analysis indicates a nonthermal origin of a lattice disordering process, and excludes interpretations based on electron-ion equilibration process, or on thermodynamic heating process leading to plasma formation.
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http://dx.doi.org/10.1038/s41598-018-36216-3 | DOI Listing |
Radiographics
February 2025
From the Department of Radiology, Nihon University School of Dentistry at Matsudo, 2-870-1 Sakaecho-Nishi, Matsudo, Chiba 271-8587, Japan (K.I., K.O., T.K.); Department of Diagnostic Radiology, National Cancer Center Hospital East, Chiba, Japan (H.K.); Department of Radiology, VA Boston Health Care System, Boston, Mass (V.C.A.A.); and Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Mass (O.S.).
Various new dental treatment methods have been introduced in dental clinics, and many new materials have been used in recent years for dental treatments. Dentistry is divided into several specialties, each offering unique treatments, such as endodontics, implantology, oral surgery, and orthodontics. CT and MR images after dental treatment reveal a variety of hard- and soft-tissue changes and dental materials, which often cause image artifacts.
View Article and Find Full Text PDFPurpose: To compare remineralisation efficacy between silver diamine fluoride (SDF) combined with potassium iodide (KI) and sodium fluoride (NaF) varnish using hydroxyapatite (HAP) artificial white spot lesions (AWSLs) demineralisation model.
Materials And Methods: A total of 25 HAP disks was randomly divided into five groups (n = 5): baseline, AWSLs, deionized water (DW), SDF-KI or F-varnish. After AWSLs were developed, the specimen was treated with either deionized water, SDF-KI or F-varnish.
Adv Mater
January 2025
MOE Key Laboratory for UV Light-Emitting Materials and Technology, Department of Physics, Northeast Normal University, Changchun, 130024, P. R. China.
Avoiding severe structural distortion, irreversible phase transition, and realizing the stabilized multielectron redox are vital for promoting the development of high-performance NASICON-type cathode materials for sodium-ion batteries (SIBs). Herein, a high-entropy NaVFeTiMnCr(PO) (HE-NaTMP) cathode material is prepared by ultrafast high-temperature shock, which inhibits the possibility of phase separation and achieves reversible and stable multielectron transfer of 2.4/2.
View Article and Find Full Text PDFAdv Mater
January 2025
Max Planck Institute for Solid State Research, Heisenbergstr. 1, 70569, Stuttgart, Germany.
The rapid advancement of covalent organic frameworks (COFs) in recent years has firmly established them as a new class of molecularly precise and highly tuneable porous materials. However, compared to other porous materials, such as zeolites and metal-organic frameworks, the successful integration of hierarchical porosity into COFs remains largely unexplored. The challenge lies in identifying appropriate synthetic methods to introduce secondary pores without compromising the intrinsic structural porosity of COFs.
View Article and Find Full Text PDFSci Rep
January 2025
Division of Mechanical and Biomedical Engineering, Ewha Womans University, Seoul, 03760, Republic of Korea.
This contribution details a new high-fidelity finite element analysis (FEA) methodology for the investigation of the effect of the graft size on the pressure distribution developing at the calcaneocuboid joint after the Evans osteotomy procedure. The FEA model includes all 28 bones of the foot up to the distal end of fibula and tibia as well as soft tissues, tendons, and muscles. The developed FEA model was validated by comparing the in-vivo pressure distribution on the foot plantar with the in-silico results, resulting in a low deviation equal to 7.
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