In this study, we design a highly efficient plasma source using a magnetic mirror trap with two opposing permanent magnets for a miniature high-efficiency ion pump. First, we simulated the distribution of the magnetic field line formed by the proposed magnetic mirror configuration. By optimizing the distance between two opposing permanent magnets and size of these magnets, a magnetic mirror ratio value of 27 could be obtained, which is an electron confinement efficiency of over 90%. We also conducted an experiment on a high-efficiency discharge plasma source for a miniature ion pump using an optimized magnetic circuit. As a result, we revealed that the proposed magnetic circuit has a pronounced effect on plasma generation, particularly in the high-vacuum region.
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http://dx.doi.org/10.3390/s23021040 | DOI Listing |
Rev Sci Instrum
January 2025
State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, China.
Atom interferometry shows high sensitivity for inertial measurements in the laboratory, but it faces difficulties in field applications because of a trade-off between sensitivity and size. Therefore, there is an urgent need to develop a small sensor with high resolution for measuring acceleration and rotation in inertial navigation applications. Presented here is a miniaturized inertial sensor capable of measuring acceleration and rotation simultaneously based on high-resolution dual atom interferometers.
View Article and Find Full Text PDFNMR Biomed
March 2025
Department of Radiology, Clínica Universidad de Navarra, Pamplona, Spain.
Hemodynamic measurements such as cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) can provide useful information for the diagnosis and characterization of brain tumors. Previous work showed that arterial spin labeling (ASL) in combination with vasoactive stimulation enabled simultaneous non-invasive evaluation of both parameters, however this approach had not been previously tested in tumors. The aim of this work was to investigate the application of this technique, using a pseudo-continuous ASL (PCASL) sequence combined with breath-holding at 3 T, to measure CBF and CVR in high-grade gliomas and metastatic lesions, and to explore differences across tumoral-peritumoral regions and tumor types.
View Article and Find Full Text PDFQuant Imaging Med Surg
January 2025
Department of Imaging and Interventional Radiology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.
Fatty acid can potentially serve as biomarker for evaluating metabolic disorder and inflammation condition, and quantifying the double bonds is the key for revealing fatty acid information. This study presents an assessment of a deep learning approach utilizing deep image prior (DIP) for the quantification of double bonds and methylene-interrupted double bonds of triglyceride derived from chemical-shift encoded multi-echo gradient echo images, all achieved without the necessity for network training. The methodology implemented a cost function grounded in signal constraints to continually refine the neural network's parameters on a single slice of images through iterative processes.
View Article and Find Full Text PDFFront Neurosci
January 2025
Beijing Tongren Eye Center, Beijing Tongren Hospital, Beijing Key Laboratory of Ophthalmology & Visual Sciences, Capital Medical University, Beijing, China.
Purpose: To investigate the changes in cerebral hemispheric functional connections in patients with acute acquired concomitant esotropia (AACE) and their relationship with clinical manifestations, utilizing voxel-mirrored homotopic connectivity (VMHC).
Methods: A prospective, observational study was conducted involving 32 AACE patients and 31 age-, sex-, and education-matched healthy controls (HC). The resting-state functional magnetic resonance imaging (rs-fMRI) signals, binocular vision function, and psychometric scale scores were collected rs-fMRI data and structural image data were analyzed for VMHC, and a two-sample -test was used to analyze the differences in VMHC between groups.
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