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The growing population of space debris poses significant risks to operational satellites and future space missions, necessitating innovative and efficient tracking solutions. Ground-based radar for space surveillance has been a central area of research since the early Space Age, with recent advancements emphasizing the use of bistatic radar systems that incorporate sensitive radio telescopes as receivers. This approach offers a cost-effective and scalable solution for monitoring space debris. Preliminary observations demonstrated the viability of employing radio telescopes in bistatic configurations for effective debris tracking. This review provides a comprehensive analysis of experiments utilizing radio telescopes as bistatic receivers, highlighting key advancements, challenges, and potential applications in space surveillance systems. By detailing the progress in this field, this study underscores the critical role of bistatic radar systems in mitigating the growing threat of space debris.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC12074451 | PMC |
http://dx.doi.org/10.3390/s25092900 | DOI Listing |
Chem Sci
September 2025
Department of Chemistry, University of Hawai'i at Manoa Honolulu HI 96822 USA
By connecting laboratory dynamics with cosmic observables, this work highlights the critical role of reactions between highly reactive species in shaping the molecular inventory of the interstellar medium and opens new windows into the spectroscopically elusive corners of astrochemical complexity. The gas phase formation of distinct CH isomers is explored through the bimolecular reaction of tricarbon (C, XΣ ) with the vinyl radical (CH, XA') at a collision energy of 44 ± 1 kJ mol employing the crossed molecular beam technique augmented by electronic structure and Rice-Ramsperger-Kassel-Marcus (RRKM) calculations. This barrierless and exoergic reaction follows indirect dynamics and is initiated by the addition of tricarbon to the radical center of the vinyl radical forming a symmetric doublet collisional complex (CCCCHCH).
View Article and Find Full Text PDFSensors (Basel)
August 2025
Dipartimento di Ingegneria dell'Informazione, delle Infrastrutture e dell'Energia Sostenibile (DIIES), Università degli Studi Mediterranea di Reggio Calabria, IT-89123 Reggio Calabria, Italy.
This study presents a convex optimization framework for beam synthesis in Square Kilometre Array low-frequency radio telescope stations configured in a sunflower-like layout. The method minimizes the peak sidelobe level by computing an optimized set of beamforming weights, enabling precise control of the main beam while preserving angular resolution. The framework is validated through full-wave electromagnetic simulations based on detailed physical models of the antenna elements and station geometry.
View Article and Find Full Text PDFWe report on the 2024 September 9 sustained gamma-ray emission (SGRE) event observed by the Large Area Telescope (LAT) on board the Fermi satellite. The hevent was associated with a backside solar eruption observed by multiple spacecraft such as the Solar and Heliospheric Observatory (SOHO), Solar Terrestrial Relations Observatory (STEREO), Parker Solar Probe (PSP), Solar Orbiter (SolO), Solar Dynamics Observatory (SDO), Wind, and GOES, and by ground-based radio telescopes. Fermi/LAT observed the SGRE after the EUV wave from the backside eruption crossed the limb to the frontside of the Sun.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
August 2025
Jiangxi Cardiovascular Research Institute, Jiangxi Provincial People's Hospital, The First Affiliated Hospital of Nanchang Medical College, Nanchang, Jiangxi, China.
Introduction: Dysregulation of glucolipid metabolism is a central pathological mechanism underlying acute decompensated heart failure (ADHF) and significantly impacts its poor prognosis. This study aims to investigate the association between the high-density lipoprotein cholesterol-modified triglyceride-glucose index (defined as TyG/HDL-C) and their interaction with 30-day mortality in patients with ADHF.
Methods: From 2018 to 2024, 2,329 ADHF patients enrolled in the Jiangxi-ADHF II cohort were included.
Active mode mismatch sensing and control can facilitate optimal coupling in optical cavity experiments such as interferometric gravitational wave detectors. In this paper, we demonstrate a radio-frequency (RF) beam wavefront curvature modulation-based mode mismatch sensing scheme inspired by the previously proposed RF beam jitter alignment sensing scheme. The proposed mode mismatch sensing scheme uses an electro-optic lens (EOL) device that is designed to provide the required beam wavefront curvature actuation, as well as a mode converting telescope that rephases the RF second-order modes and generates a non-vanishing mode mismatch sensing signal.
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