Phys.org April 28, 2021 An international team of researchers (USA – Lawrence Berkeley National Laboratory, Finland, Singapore, Germany) has measured depth-resolved photoluminescence of nitrogen-vacancy (NV−) centers formed along the tracks of swift heavy ions (SHIs) in synthetic single crystal diamonds that had been doped with nitrogen during crystal growth. Analysis of the spectra showed that NV− centers are formed preferentially within regions where electronic stopping processes dominate and not at the end of the ion range where elastic collisions lead to the formation of vacancies and defects. Thermal annealing further increased NV yields after irradiation with SHIs preferentially in regions […]
Lightning and subvisible discharges produce molecules that clean the atmosphere
Phy.org April 29, 2021 Lightning increases the atmosphere’s ability to cleanse itself by producing nitric oxide (NO), leading to atmospheric chemistry that forms ozone (O3) and the atmosphere’s primary oxidant, the hydroxyl radical (OH). A team of researchers (Pennsylvania State University, Texas Tech University, NOAA, University of Oklahoma, University of Maryland, University of Alaska, University of Colorado) analyzed data from their 2012 airborne study of deep convection and chemistry which showed that lightning also directly generates the oxidants OH and the hydroperoxyl radical (HO2). Extreme amounts of OH and HO2 were discovered and linked to visible flashes occurring in front […]
A more efficient, safer alternative to sourcing copper via bacteria
Phys.org April 24, 2021 The chemical synthesis of monoatomic metallic copper is unfavorable as it requires inert or reductive conditions and the use of toxic reagents. An international team of researchers (Brazil, USA – University of Houston, Japan) describes how a copper-resistant bacterium isolated from a copper mine in Brazil converts toxic copper ions to stable single-atom copper. They propose a biosynthetic mechanism for production of copper via proteomics analysis. This microbial conversion is carried out naturally under aerobic conditions eliminating toxic solvents. They demonstrated the abundant intracellular synthesis of single-atom zero-valent copper by the bacterium. The finding shows that […]
Nature provides inspiration for breakthrough in self-regulating materials
Phys.org April 27, 2021 To make a series of oscillators to work in unison with each other, a team of researchers (UMass Amherst, Boston University, Harvard University, University of Colorado) has developed a versatile platform of light-driven active particles with interaction geometries that can be reconfigured on demand, enabling the construction of oscillator and spinner networks. The platform relies on the Marangoni effect, which is a phenomenon that describes the movement of solids along the interface between two fluids driven by changes in surface tension. They used hydrogel nanocomposite disks made up of polymer gels and nanoparticles of gold, which […]
New 2D superconductor forms at higher temperatures than ever before
Phys.org April 27, 2021 The distinctive electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. An international team of researchers (USA – Argonne National Laboratory, University of Illinois, China) has discovered superconductivity in electron gases formed at interfaces between (111)-oriented KTaO3 and insulating overlayers of either EuO or LaAlO3. The superconducting transition temperature, as high as 2.2 kelvin, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Similar electron gases at KTaO3 (001) interfaces remain normal down to 25 millikelvin. The critical field and current-voltage measurements indicated that the superconductivity is […]
New two-dimensional material
Science Daily April 27, 2021 An international team of researchers (USA – Carnegie Institution for Science, Howard University, University of Chicago, Argonne National Laboratory, Germany, France, Russia, Sweden, the Netherlands, China) used the laser-heated diamond anvil cell technique with pressures of up to 100 gigapascals, to synthesize a Dirac material beryllonitrene (BeN4). These are beryllium polynitrides, some of which conform to the monoclinic, others to the triclinic crystal system. The triclinic beryllium polynitrides exhibit an unusual characteristic when the pressure drops. They take on a crystal structure made up of layers. Each layer contains zigzag nitrogen chains connected by beryllium […]
Q&A: Are we on the brink of a new age of scientific discovery?
Phys.org April 27, 2021 In 2001 at the Brookhaven National Laboratory in Upton, New York, a facility used for research in nuclear and high-energy physics, scientists experimenting with a subatomic a muon encountered something unexpected. According to relativistic quantum mechanics, the strength of the muon’s magnetic moment should be two in appropriate dimensionless units. The Standard Model states, however, that it is not two, it is a little bit bigger, and that difference is the magnetic anomaly. Brookhaven experiment challenges the Standard Model with increasing levels of precision, it signifies that there is something else. We know that the Standard […]
Researchers complete high-precision time-frequency dissemination
Phys.org April 26, 2021 Microwave-based satellite–ground links cannot fully satisfy the requirements of metrology, navigation, positioning, and very long baseline interferometers. Researchers in China investigated the possibility of an optical-based satellite–ground link, where the transferred carriers are pulsed lasers, resulting in a link with a high time resolution and a large ambiguous range. They analyzed the parameters of satellites in different orbits and concluded that high-orbit links enable more stable time–frequency comparison or dissemination by taking advantage of the long duration, a large common view range, and the lower relativistic effects. They performed a 16 km free-space transfer experiment to […]
Researchers demonstrate fully recyclable printed electronics
EurekAlert April 26, 2021 Developments in transient electronics have focused on increasing the biocompatibility, whereas efforts to develop methods to recapture and reuse materials have focused on conducting materials, while neglecting other electronic materials. Researchers at Duke University have made all-carbon thin-film transistors using crystalline nanocellulose as a dielectric, carbon nanotubes as a semiconductor, graphene as a conductor and paper as a substrate. They developed a crystalline nanocellulose ink that is compatible with nanotube and graphene inks and can be written onto a paper substrate using room-temperature aerosol jet printing. The addition of mobile sodium ions to the dielectric improves […]
Scientists harness molecules into single quantum state
Science Daily April 28, 2021 For molecules to reach the quantum regime usually requires efficient cooling at high densities, which is frequently hindered by fast inelastic collisions that heat and deplete the population of molecules. An international team of researchers (USA- University of Chicago, China) prepared two-dimensional Bose–Einstein condensates of spinning molecules by inducing pairing interactions in an atomic condensate near a g-wave Feshbach resonance. The trap geometry and the low temperature of the molecules help to reduce inelastic loss, ensuring thermal equilibrium. They investigated the unpairing dynamics in the strong coupling regime and found that near the Feshbach resonance […]