Stabilizing in-transition phases of superlattices through shape control of silver nanocrystals - Science | AAAS

In optical fibers, chips and other light-guiding devices, minor defects can scatter photons and disrupt their path. A new study demonstrates a way to reveal properties which, in certain systems, help light wave behavior withstand such flaws. The method could help speed up the search for new kinds of electronics and optical technologies, and contribute to more reliable quantum devices.

We’re sharing this article early to provide faster access to peer-reviewed, accepted research. It is citable and carries a permanent DOI. This version is subject to further edits and will be replaced automatically by the final Version of Record. All legal disclaimers apply. AbstractThis study presents the development of high-sensitivity real-time X-ray dosimeters based on room-temperature-vulcanized (RTV-2) silicone nanocomposites incorporating 0–60 wt% Bi2O3 nanoparticles, fabricated via solution casting. Structural and morphological characterization using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) with elemental mapping, and elemental analysis confirmed the uniform dispersion of monoclinic Bi2O3 nanorods within the amorphous RTV-2 matrix. Complementary Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and thermogravimetric analysis (TGA) validated the chemical integrity, thermal stability, and mechanical robustness of the resulting nanocomposites. Dosimetric performance was investigated under diagnostic-range X-ray exposure using a COMET MXR 320/26 source (dose rates: 2.8–12 mGy/min).

Antarctica’s towering ice cliffs may be more resilient than scientists once feared. New satellite observations reveal surprising natural mechanisms that could reshape predictions of future sea level rise. Credit: ShutterstockSatellite observations show Antarctic ice cliffs stabilizing after unexpectedly rapid collapse, challenging assumptions about runaway ice loss and its contribution to rising seas. Antarctica’s ice shelves help hold back the ice sheet behind them, but rising temperatures are causing these supports to melt and break apart at record rates. As sheer ice cliffs are left exposed, scientists have worried that a collapse could reveal a taller cliff farther inland, setting off a chain of failures that eats into the ice sheet and raises seas worldwide. In a four-year satellite survey of more than 15,000 Antarctic ice cliffs, researchers at MIT and the Woods Hole Oceanographic Institution (WHOI) found that the tallest cliffs they examined closely did collapse, and the ice sheet in those regions retreated faster than models predicted. “But that retreat was short-lived,” says Caroline Needell, a graduate student in the MIT-WHOI Joint Program.