Resonant interaction of laser pulses with plasmons is used to identify vibrations associated with isolated spheres and pairs of contacting spheres in a system of gold nanoparticles. The optical pulses generate coherent mechanical oscillations of both monomers and dimers in the 5-150 GHz range, the amplitudes of which exhibit a strong enhancement when the laser central wavelength is tuned to resonate with the corresponding plasmon. Because of the resonant selection in the excitation process, the widths of the acoustic modes are significantly smaller than broadening caused by the spread in radii in the ensemble.
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http://dx.doi.org/10.1021/nl201648e | DOI Listing |
Rev Esc Enferm USP
January 2025
Universidade Federal de Viçosa, Departamento de Medicina e Enfermagem, Viçosa, MG, Brazil.
Objective: To compare the effectiveness of ear acupuncture with laser and needles in the treatment of anxiety in university students in the post-pandemic context of Covid-19, as well as to evaluate the possible symptoms or adverse reactions triggered by the interventions.
Method: Randomized clinical trial carried out with 126 university students, allocated to the "Needle" (control) and "Laser" (experimental) groups. Five ear acupuncture sessions were performed.
J Phys Chem A
January 2025
Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
This study investigates the motion of an electron in a Coulomb potential driven by an intense linearly polarized XUV laser pulse analyzed using Gordon-Volkov wave functions. The wave function is decomposed into spherical partial waves to model the scattered electron wave packet after the recollision with a proton. This interaction triggers high harmonic generation, producing coherent X-ray pulses with frequencies that are integer multiples of the XUV field.
View Article and Find Full Text PDFProg Addit Manuf
July 2024
Empa Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600 Dübendorf, Switzerland.
Fast and accurate representation of heat transfer in laser powder-bed fusion of metals (PBF-LB/M) is essential for thermo-mechanical analyses. As an example, it benefits the detection of thermal hotspots at the design stage. While traditional physics-based numerical approaches such as the finite element (FE) method are applicable to a wide variety of problems, they are computationally too expensive for PBF-LB/M due to the space- and time-discretization requirements.
View Article and Find Full Text PDFACS Phys Chem Au
January 2025
Department of Medical Applied Chemistry, Chung Shan Medical University, Taichung 402, Taiwan.
Novel coumarin-triphenyliminophosphorane (TPIPP) fluorophores, synthesized via a nonhydrolytic Staudinger reaction, exhibit remarkable redox-responsive optical properties. Upon chemical and electrochemical oxidation, these compounds display a hypsochromic shift in absorption from 430 to 350 nm, accompanied by up to 11-fold fluorescence enhancement under 405 nm excitation. The fluorescence switching occurs at an electrochemical oxidation potential of approximately +2.
View Article and Find Full Text PDFSensors (Basel)
January 2025
Soreq NRC, Yavne 81800, Israel.
Fiber Bragg gratings (FBGs) inscribed by UV light and different femtosecond laser techniques (phase mask, point-by-point, and plane-by-plane) were exposed-in several irradiation cycles-to accumulated high doses of gamma rays (up to 124 MGy) and neutron fluence (8.7 × 10/cm) in a research-grade nuclear reactor. The FBG peak wavelengths were measured continuously in order to monitor radiation-induced shifts.
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