In the current article, the spectral properties and electron collision (total and magnetic) excitation cross sections of ions taking placed in quantum plasmas are investigated. These cross sections are further used to study the polarization and angular distribution characteristics of the de-excitation radiation X-ray spectra, which play an important role in basic theoretical research, the diagnosis of the plasma environment, and the design of optical devices. To do so, a distorted wave method within the relativistic Dirac-Coulomb atomic structure scheme is suggested. The effective interaction potential between electrons and particles in hot quantum plasmas in the method is determined using a quantum approach that incorporates the influence of effective plasma screening effects caused by collective plasma oscillations. This potential replaces the traditional Coulomb interaction potential and is used in solving the modified Dirac equation to obtain the bound and continuum electron wave functions. Higher-order relativistic effects, such as the Breit interaction and the dominant quantum electrodynamics corrections, are added to enhance the accuracy of the method. Detailed calculations for the relativistic atomic structure and collision excitation dynamics process are carried out, taking the highly stripped H-like O ion of astrophysical importance as an illustrative example. Detailed investigations are also conducted on the variation of energies, collision cross sections, and fluorescence polarizations as functions of the plasma parameters. Our results suggest that the joint effects of shielding and plasma coupling lead the energies, cross sections and fluorescence polarizations decrease (compared with the isolated case). The angular distribution of the X-ray fluorescence emission shows large change, suggesting their sensitivity to these effects. This study not only offers a valuable approach to investigating the plasma shielding and plasmon coupling effects in quantum plasmas but also holds significant relevance for applications in controlled nuclear fusion, astrophysical plasmas and so on.
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http://dx.doi.org/10.1016/j.apradiso.2024.111420 | DOI Listing |
BMC Public Health
January 2025
Biomedical Science Programme, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia.
Background: After two years of the COVID-19 pandemic, Malaysia began the transition to the endemic phase. students at higher education institutes are among those who were affected by the COVID-19 outbreak and deserve further attention. Hence, this study aimed to assess the knowledge, attitude, and practice (KAP) associated with COVID-19 among public university undergraduate students in Malaysia during the endemic phase.
View Article and Find Full Text PDFSci Rep
January 2025
Yunnan Key Laboratory of Plateau Emission of Internal Combustion Engines, Kunming Yunnei Power CO., LTD., Kunming City, 650200, People's Republic of China.
Traditional aluminum-silicon alloy pistons are gradually replaced by steel pistons, which has become the trend of future diesel engine development. However, the efficient design and broad application of steel pistons are limited by the higher density of steel. For this reason, a new lightweight design method for steel pistons in diesel engines was proposed in this paper.
View Article and Find Full Text PDFAnal Chem
January 2025
School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian, Liaoning 116024, China.
A linear spot-type multipass cell-enhanced fiber-optic photoacoustic gas microprobe is proposed. To further reduce the volume of the gas chamber and enhance the photoacoustic signal, we designed the cross section of the photoacoustic tube as a slit with a height of 10 mm and a width of 1.5 mm.
View Article and Find Full Text PDFNeuroimage
January 2025
Department of Diagnostic Radiology, City of Hope National Medical Center, 1500 E Duarte, CA 91010, USA.
Background: The aim of this study was to establish an iron overload rat model to simulate the elevated iron levels in patients with thalassemia and to investigate the potential association between hippocampal iron deposition and cognition.
Methods: Two groups of iron overloaded rats and one group of control rats were used for this study. The Morris water maze (MWM) was used to test spatial reference memory indicated by escape latency time and number of MWM platform crossings.
Knee
January 2025
Department of Orthopaedics and Traumatology, Haseki Training and Research Hospital, University of Health Sciences, Istanbul, Turkey.
Background: The aim of this study was to predict intraoperative graft diameter with our new method by evaluating the cross-sectional areas (CSAs) of the hamstrings in axial sections of MRI.
Methods: This study included 78 patients who underwent single-bundle ACLR between 2022 and 2023. MRIs of the patients were evaulated preoperatively and four CSAs of the hamstring tendons were measured in two different regions by two participants.
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