Detecting hidden nanostructures by converting light into sound

Nanowerk  July 8, 2020 Using laser-induced, extremely high-frequency ultrasound researchers in the Netherlands detected diffraction gratings buried below a stack of tens of 18-nm-thick SiO2 and Si3N4 layers and an optically opaque metal layer. The shape and amplitude of a buried metal grating were encoded on the spatial phase of the reflected acoustic wave. They showed that the complex shape of the diffracted signal as a function of time can be reproduced using a comprehensive numerical model that includes the generation, propagation, and optical detection of the acoustic waves. The results show that laser-induced ultrasound is a promising technique for […]

Engineers design a reusable, silicone rubber face mask

MIT News  July 9, 2020 A team of researchers in US (MIT, Brigham and Women’s Hospital) has designed a new face mask made of durable silicone rubber. Liquid silicone rubber can be easily molded into any shape using injection molding. It can be manufactured using injection molding, which is widely used in factories around the world. The mask includes an N95 filter, but it requires much less N95 material than a traditional N95 mask. Th filters are designed to be replaced after every use, while the rest of the mask can be sterilized and reused. They tested several different sterilization […]

Generator developed for harvesting energy from droplets

Phys.org  July 8, 2020 An international team of researchers (the Netherlands, China) has designed a charge trapping‐based electricity generator (CTEG) for passive energy harvesting from water droplets with high efficiency. The hydrophobic fluoropolymer films utilized in CTEG are pre‐charged by a homogeneous electrowetting‐assisted charge injection method, allowing an ultrahigh negative charge density. By connecting the bottom electrode and top electrode of a Pt wire, instantaneous current is generated from continuously falling water droplets. CTEG devices have shown robustness without appreciable degradation for intermittent testing during 100 days. The approach is applicable for energy harvesting from wave‐like oscillatory fluid motion. it […]

Harvesting hydrogen from nanogardens

Nanowerk  July 3, 2020 By manipulating (electro)chemical gradients using a combined hydrothermal and electrodeposition strategy, an international team of researchers (China, the Netherlands) has shown the controlled growth of Co(OH)2 nanostructures, mimicking the process of garden cultivation. The resulting “nano-garden” can selectively contain different patterns, all of which can be fully phosphidated into CoP without losing the structural integrity. Under pH-universal conditions, the CoP “soil + flower-with-stem” structure shows a much more “effective” surface area for gas-evolving reactions with lower activation and concentration overpotentials. This provides superior bifunctional catalytic activity for both reactions, outperforming noble metal counterparts…read more. Open Access […]

The Locust Plague in East Africa Is Sending Us a Message, And It’s Not Good News

Science Alert  July 3, 2020 Swarming in the trillions, voracious insects are destroying precious pastures and crops in what is considered the worst regional locust plague in decades, from Kenya through Ethiopia and Yemen, reaching as far as parts of northern India. According to researchers in Kenya and Germany the first major swarms emerged late last year, after unusually warm and wet weather, and they numbered in the hundreds of billions. Come April, the next generation hit the skies, this time in the trillions. The third generation is expected to take off this July in even larger numbers. Treating huge […]

Magnetic memory states go exponential

EurekAlert  July 9, 2020 When spintronic devices are used for storing data, the number of stable states sets an upper limit on memory capacity. Researchers in Israel have shown that relatively simple structures can support exponential number of magnetic states – much greater than previously thought. They studied structures that are magnetic thin films patterned in the form of N crossing ellipses which have two to the power of 2N magnetization states. The researchers demonstrated switching between the states by generating spin currents. The finding may pave the way to multi-level magnetic memory with extremely large number of states per […]

New biomaterial could shield against harmful radiation

Phys.org  July 8, 2020 Melanins are a family of heterogeneous biopolymers found ubiquitously across plant, animal, bacterial, and fungal kingdoms where they act variously as pigments and as radiation protection agents. An international team of researchers (USA – Northwestern, UC San Diego, University of Akron, Belgium) synthesized ” selenomelanin” enriching melanin with selenium instead of sulfur to provide better protection against X-rays as selenium is an essential micronutrient that plays an important role in cancer prevention. Results demonstrated that selenomelanin offers superior protection from radiation, it is easy to synthesize. Selenomelanin can be biosynthesized, with appropriate nutrients can produce selenomelanin […]

New process enables lithium mining in Germany

Tech Xplore  July 7, 2020 Considerable quantities of the element lithium are deeply hidden in rock formations below the Upper Rhine Trench: dissolved in salty thermal water reservoirs. Chile, Argentina, and Australia account for more than 80 percent of global production. Researchers in Germany have developed an environmentally friendly process to extract lithium from the existing infrastructure of geothermal plants, through which up to two billion liters of thermal water flow every year. There can be up to 200 milligrams per liter. The process involves filtering out the lithium ions from the thermal water and concentrated until lithium can be […]

Physics team observes extremely fast electronic changes in real time in a special material class

Phys.org  July 7, 2020 Topologically protected Weyl semimetal phase in the transition metal dichalcogenide Td-WTe2 can be controlled and, ultimately, destroyed upon the coherent excitation of an interlayer shear mode. An international team of researchers (Germany, China) provide direct experimental evidence that the shear mode acts on the electronic states near the phase-defining Weyl points. They observed a periodic reduction in the spin splitting of bands. Comparison with higher-frequency coherent phonon modes finally proved the shear mode-selectivity of the observed changes in the electronic structure. findings reveal direct experimental insights into electronic processes that are of vital importance for a […]

Porous graphene ribbons doped with nitrogen for electronics and quantum computing

Science Daily  July 8, 2020 High concentration of nitrogen atoms in the crystal lattice causes graphene ribbons to magnetize when subjected to a magnetic field. An international team of researchers (Switzerland, UK) expect these porous, nitrogen-doped graphene ribbons to display extraordinary magnetic properties. They have produced porous graphene ribbons in which specific carbon atoms in the crystal lattice are replaced with nitrogen atoms. They demonstrated that these new graphene ribbons were no longer electrical conductors, like pure graphene, but behaved as semiconductors. According to the researchers the doped graphene ribbons could be of interest for applications in quantum computing…read more. […]