Power spectra of cortical potentials at frequencies of 1-60 Hz were assessed in subjects in the state of resting with the eyes open, after listening to instructions, and during the prestimulus periods at the stages of forming and testing a cognitive set to a facial expression. Comparative assessment of power spectra in five frequency ranges (2-7, 8-13, 14-20, 21-40, and 41-60 Hz) showed significant decreases in the power of potentials in the 1-20 Hz frequency band in most subjects, along with a parallel increase in power in the 21-60 Hz band in all states, as compared with the resting state. Interregional differences in power were maximal in the 2-7 and 41-60 Hz bands and minimal in the 14-20 Hz band. In terms of power dynamics in the states being compared, intergroup differences were seen only at the test stage. Thus, a larger proportion of subjects with the plastic type of set had greater power in the gamma frequency range than was the case in subjects with the rigid type of set.
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http://dx.doi.org/10.1007/s11055-010-9327-z | DOI Listing |
Phys Rev Lett
December 2024
Duke University, Department of Physics, Durham, North Carolina 27708, USA.
The emergence of a quantum spin liquid (QSL), a state of matter that can result when electron spins are highly correlated but do not become ordered, has been the subject of a considerable body of research in condensed matter physics [1,2]. Spin liquid states have been proposed as hosts for high-temperature superconductivity [3] and can host topological properties with potential applications in quantum information science [4]. The excitations of most quantum spin liquids are not conventional spin waves but rather quasiparticles known as spinons, whose existence is well established experimentally only in one-dimensional systems; the unambiguous experimental realization of QSL behavior in higher dimensions remains challenging.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
Department of Physics and Astronomy & Wright Center for Photovoltaic Innovation and Commercialization, The University of Toledo, Toledo, Ohio 43606, United States.
Wide band gap FACsPb(IBr) perovskite photovoltaic (PV) devices are measured by spectroscopic ellipsometry in the through-the-glass configuration and analyzed to determine the complex optical property spectra of the perovskite absorber as well as the structural properties of all constituent layers. This information is used to simulate external quantum efficiency (EQE) spectra, to calculate PV device performance parameters such as short circuit current density, open circuit voltage, fill factor, and power conversion efficiency, and to develop strategies for increasing the accuracy of predictions. Simulations and calculations tend to overestimate PV device performance parameters, undermining the accuracy and usefulness of those simulations.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Science and Technology on Aerospace Chemical Power Laboratory, Laboratory of Emergency Safety and Rescue Technology, Hubei Institute of Aerospace Chemotechnology, Xiangyang 441003, China.
A comprehensive analysis of BiOBr has been carried out using first-principles density-functional theory (DFT) to explore the electronic structure, energy band structure, and essential properties related to its photocatalytic performance. DFT calculations reveal that BiOBr, BiOBr, BiOBr, BiOBr, BiOBr, and BiOBr have different indirect bandgap values of 2.46 eV, 2.
View Article and Find Full Text PDFWe report the radiation-induced darkening (RD) effect caused by X-ray radiation and the bleaching effect caused by D/H/N loading in self-developed Yb-doped large mode-area photonic crystal fibers (LMA PCFs). The decrease in the slope efficiency caused by irradiation decays exponentially with an increase in the X-ray radiation doses, and the radiation-induced gain variation (RIGV) showed a linear decay trend with increasing irradiation doses. The slope efficiency of Yb-doped LMA PCF, which significantly degraded from 71.
View Article and Find Full Text PDFNonlinear emission phenomena observed in transition metal dichalcogenides (TMDCs) have significantly advanced the development of robust nonlinear optical sources within two-dimensional materials. However, the intrinsic emission characteristics of TMDCs are inherently dependent on the specific material, which constrains their tunability for practical applications. In this study, we propose a strategy for the selective enhancement and modification of second-harmonic generation (SHG) emission in a multilayer WS flake through the implementation of a silicon (Si)-based circular Bragg grating (CBG) structure positioned on an Au/SiO substrate.
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