The active shielding technique has great potential for radiation protection in space exploration because it has the advantage of a significant mass saving compared with the passive shielding technique. This paper demonstrates a Monte Carlo-based approach to evaluating the shielding effectiveness of the active shielding technique using confined magnetic fields (CMFs). The International Commission on Radiological Protection reference anthropomorphic phantom, as well as the toroidal CMF, was modeled using the Monte Carlo toolkit Geant4. The penetrating primary particle fluence, organ-specific dose equivalent, and male effective dose were calculated for particles in galactic cosmic radiation (GCR) and solar particle events (SPEs). Results show that the SPE protons can be easily shielded against, even almost completely deflected, by the toroidal magnetic field. GCR particles can also be more effectively shielded against by increasing the magnetic field strength. Our results also show that the introduction of a structural Al wall in the CMF did not provide additional shielding for GCR; in fact it can weaken the total shielding effect of the CMF. This study demonstrated the feasibility of accurately determining the radiation field inside the environment and evaluating the organ dose equivalents for astronauts under active shielding using the CMF.
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http://dx.doi.org/10.1088/0952-4746/35/4/777 | DOI Listing |
Nursing
December 2024
Tammy McClung is a nursing instructor of the RN to BSN program at the College of Brockport, State University of New York, in Brockport, N.Y. She also holds a per diem clinical position in urgent care at the University of Rochester.
Magnetic resonance imaging (MRI) is a powerful diagnostic tool that uses strong magnetic fields and radio waves to create detailed images of the body's internal structures. This article examines the challenges associated with MRI, particularly focusing on patient anxiety and claustrophobic reactions that can lead to aborted scans. It discusses the use of anxiolytics, especially benzodiazepines, to manage these issues, while highlighting the potential risks of respiratory depression and other adverse outcomes in select patient populations.
View Article and Find Full Text PDFNanomaterials (Basel)
January 2025
Institute of Information Photonics Technology, School of Physics and Optoelectronics, Faculty of Science, Beijing University of Technology, Beijing 100124, China.
Nonlinear optics, a critical branch of modern optics, presents unique potential in the study of two-dimensional (2D) magnetic materials. These materials, characterized by their ultra-thin geometry, long-range magnetic order, and diverse electronic properties, serve as an exceptional platform for exploring nonlinear optical effects. Under strong light fields, 2D magnetic materials exhibit significant nonlinear optical responses, enabling advancements in novel optoelectronic devices.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín 050010, Colombia.
Using the effective mass approximation and the finite difference method, we examined the linear, non-linear, and total optical absorption coefficients (OAC), as well as the relative refractive index coefficients (RIC) variations for an off-center shallow donor impurity in a 2D-curved electronic nanostructure subjected to external electric and magnetic fields. Our results reveal that the peak positions of the OAC and RIC are susceptible to the geometrical angles, the impurity position, and the strength of the applied electric and magnetic fields. In particular, the positions of the OAC and RIC peaks can be shifted towards blue or red by adjusting the geometric angle.
View Article and Find Full Text PDFAdv Mater
January 2025
School of Materials Science and Engineering, Key Laboratory of Advanced Materials and Devices for Post-Moore Chips, Ministry of Education, University of Science and Technology Beijing, Beijing, 100083, China.
Magnetic antiskyrmions, the anti-quasiparticles of magnetic skyrmions, possess alternating Bloch- and Néel-type spin spirals, rendering them promising for advanced spintronics-based information storage. To date, antiskyrmions are demonstrated in a few bulk materials featuring anisotropic Dzyaloshinskii-Moriya interactions and a limited number of artificial multilayers. Identifying novel film materials capable of hosting isolated antiskyrmions is critical for memory applications in topological spintronics.
View Article and Find Full Text PDFJ Oral Biol Craniofac Res
December 2024
Department of Orthodontics, University of Washington, Seattle, USA.
Objective: To evaluate the pharyngeal airway dimensions and regional pharyngeal adipose distribution in the young adult minipig model.
Materials And Methods: Eight 7-8-months-old Yucatan minipigs, half male and female, were sedated and placed prone to scan the pharyngeal region. Magnetic resonance imaging (MRI) was performed using dynamic turbo-field echo (TFE)-sequence with respiratory gating and adipose-weighted sequence.
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