The spectral properties of the emission of a colloidal suspension of titanium dioxide particles in Rhodamine 640 perchlorate were studied systematically. The particle density rho, the dye concentration c, and the energy of the pump pulse were varied over several orders of magnitude; the dependence of the spectra on these three parameters is discussed. We discovered a strong correlation between the particle density and the dye concentration. The amplification by stimulated emission was found to be strongest when the absorption length l(a) and the mean-free-path length l(*) had approximately the same magnitude. The respective l(*) values were determined by a pulsed transmission experiment.
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http://dx.doi.org/10.1364/ol.22.001427 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
A green facile method was developed to synthesize the carbon quantum dots from barberry, a native plant, as a new carbon source. The synthesis strategy is a simple one-step hydrothermal process without requiring hazardous chemical reagents. The spherical structure of b-CDs with an average particle size of 3.
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January 2025
Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea.
A particle current generated by pumping in the absence of gradients in potential energy, density or temperature is associated with non-trivial dynamics. A representative example is charge pumping that is associated with the quantum Hall effect and the quantum anomalous Hall effect. Spin pumping, the spin equivalent of charge pumping, refers to the emission of a spin current by magnetization dynamics.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Bone Joint, Binzhou Medical University Hospital, No. 661 Huanghe 2nd Road, Binzhou, 256600, China.
This study examines the biocompatibility, osteogenic potential, and effectiveness of polyether ether ketone (PEEK) composites for treating osteonecrosis, seeking to establish a theoretical basis for clinical application. A range of PEEK composite materials, including sulfonated polyether ether ketone (SPEEK), polydopamine-sulfonated polyether ether ketone (SPEEK-PDA), bone-forming peptide-poly-dopamine-sulfonated polyether ether ketone (SPEEK-PDA-BFP), and vascular endothelial growth factor-poly-dopamine-sulfonated polyether ether ketone (SPEEK-PDA-VEGF), were constructed by concentrated sulfuric acid sulfonation, polydopamine modification and grafting of bioactive factors. The experiments involved adult male New Zealand rabbits aged 24-28 weeks and weighing 2.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
National University of Singapore, Department of Physics, Singapore 117551.
We uncover emergent universality arising in the equilibration dynamics of multimode continuous-variable systems. Specifically, we study the ensemble of pure states supported on a small subsystem of a few modes, generated by Gaussian measurements on the remaining modes of a globally pure bosonic Gaussian state. We find that beginning from highly entangled, complex global states, such as random Gaussian states and product squeezed states coupled via a deep array of linear optical elements, the induced ensemble attains a universal form, independent of the choice of measurement basis: it is composed of unsqueezed coherent states whose displacements are distributed normally and isotropically, with variance depending on only the particle-number density of the system.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Key Laboratory for Laser Plasmas and School of Physics and Astronomy, and Collaborative Innovation Center of IFSA, Shanghai Jiao Tong University, Shanghai 200240, China.
Time-dependent density functional theory (TDDFT) is widely used for understanding and predicting properties and behaviors of matter. As one of the fundamental theorems in TDDFT, Van Leeuwen theorem [Phys. Rev.
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