共找到 20 条结果
The decay of common radioactive gases, such as radon, produces stable isotopes by a sequence of daughter particles with varied half-lives. These daughter particles are a significant source of gamma, neutron, and alpha particle backgrounds that can mimic desired signals in dark matter and neutrinoless double beta decay experiments. In the LUMINA Laboratory at Southern Methodist University (SMU), studies of radon plate-out onto copper samples are conducted using one of XIA's first five UltraLo 1800 alpha counters. We present results from investigations into various mitigation approaches. A custom-built copper holder (in either plastic or metal) has been designed and produced to maximize the copper's exposure to 220Rn. The 220Rn source is a collection of camping lantern mantles. We present the current status of control and experimental methods for addressing radon exposure levels.
We apply the generalized Lomb-Scargle periodogram to the $\rm{^{123}I}$ and $\rm{^{99m}Tc}$ decay rate measurements based on data taken at the Bronson Methodist Hospital. The aim of this exercise was to carry out an independent search for sinusoidal modulation for these radionuclei (to complement the analysis in Borrello et al) at frequencies for which other radionuclei have shown periodicities. We do not find evidence for such a modulation at any frequencies, including annual modulation or at frequencies associated with solar rotation. Our analysis codes and datasets have been made publicly available.
We develop an operator splitting approach to solve diffeomorphic matching problems for sequences of surfaces in three-dimensional space. The goal is to smoothly match, at a very fast rate, finite sequences of observed 3D-snapshots extracted from movies recording the smooth dynamic deformations of "soft" surfaces. We have implemented our algorithms in a proprietary software installed at The Methodist Hospital (Cardiology) to monitor mitral valve strain through computer analysis of noninvasive patients' echocardiographies.
A groundbreaking superconducting X-ray spectrometer has begun operation at BESSY II, giving Europe its first TES-based system and boosting photon detection efficiency by up to 1,000 times。 The advance enables scientists to explore atomically thin materials, nanostructures, and ultra-dilute samples with remarkable speed and sensitivity
The global cobalt supply chain is more interconnected—and more vulnerable—than previously thought, with disruptions capable of triggering far-reaching cascades across multiple countries and industries。 Researchers warn that protecting battery supply chains will require system-wide coordination because critical bottlenecks can turn local shocks into
Order warns of national security risks if post-quantum cryptography isn't adopted in time
SETI scientists searched the interstellar object 3I/ATLAS for radio signals that could indicate extraterrestrial technology but found nothing beyond human-made interference。 Even so, the rapid-response observations helped confirm the object's natural origin and showcased how future interstellar visitors can be investigated for signs of intelligent
Physicists have solved a long-standing problem involving systems that appear to violate Newton’s third law, such as bird flocks and bacterial swarms。 By adding carefully designed “imaginary partners” to their models, they can now simulate these complex systems with unprecedented accuracy
Deep beneath the ground in China, the massive JUNO neutrino observatory has delivered its first major scientific breakthrough, achieving one of the most precise measurements yet of how elusive neutrinos change as they travel。 Using just 59 days of data, researchers sharply improved measurements of key neutrino properties, boosting confidence that J
Scientists found that transfer learning can make the search for new physics in the universe much faster, slashing the need for expensive simulations。 Yet the approach can backfire when AI relies too heavily on familiar patterns, potentially missing evidence of something truly new
What if some black holes aren’t black holes at all。 A new theoretical study suggests that when a massive star collapses, it might not form a singularity hidden behind an event horizon。 Instead, the collapse could trigger the birth of a tiny new universe inside the dying star
A new catalyst design could significantly improve the conversion of CO2 into methanol, an important fuel and chemical feedstock。 Researchers separated key reaction steps across different catalyst sites, avoiding a long-standing trade-off between speed and efficiency。 The result was about three times more methanol production than standard commercial
A bold claim that the universe’s accelerating expansion was an illusion has been put to the test—and failed。 Researchers found that the study behind the controversy made key mistakes when analyzing supernova data。 After revisiting the evidence, astronomers concluded that cosmic acceleration remains as strong as ever
Scientists have developed an artificial photosynthesis system that essentially regulates itself, eliminating the need for batteries used in many current designs。 The key innovation is an electrolyzer that automatically adapts to changing sunlight by altering its electrical properties as it heats up。 This keeps solar fuel production more stable whil
Researchers found that a Chinese sodium-ion battery performs far better than expected, with production quality and design features comparable to Tesla’s batteries。 If engineers can improve cold-weather charging and energy density, sodium could become a cheaper and more abundant alternative to lithium for EVs and large-scale energy storage
NASA has selected the Artemis III crew for a high-stakes 2027 mission designed to test the future of lunar exploration。 Astronauts will launch aboard Orion and perform unprecedented docking operations with lunar landers being developed by both Blue Origin and SpaceX。 The mission will require a remarkable sequence of heavy-lift rocket launches and c
Researchers gave top AI models a classic attention test used in psychology and found a major flaw。 While the models could correctly name colors in short lists, their performance deteriorated sharply as the task became longer and more complex。 Some leading systems fell from over 90% accuracy to nearly complete failure