Science Daily July 27, 2021 A transmitter traditionally must first detect a device presence and position to be able to send energy in its direction. Researchers in Finland have designed a proof-of-concept device which creates power transfer channels in all directions, automatically tuning channels when receiving devices are in motion. Because of self-tuning, the device does not need complex electronics to connect with receivers embedded in devices and it can be moved freely within a wide charging range. By winding the coils in a specific way, they created two kinds of electromagnetic fields: one going outwards and the other around. […]
Top 10 Science and Technology Inventions for the Week of July 23, 2021
01. Low-cost, sustainable, readily available plasma technology could replace one of the world’s 02. The paradox of a free-electron laser without the laser 03. Achilles heel of graphene exposed 04. Future information technologies: Topological materials for ultrafast spintronics 05. Microbially produced fibers: Stronger than steel, tougher than Kevlar 06. Making clean hydrogen is hard, but researchers just solved a major hurdle 07. Nanostructures enable record high-harmonic generation 08. New material could mean lightweight armor, protective coatings 09. Scientists create rechargeable swimming microrobots using oil and water 10. The era of single-spin color centers in silicon carbide is approaching And others… […]
Achilles heel of graphene exposed
Nanowerk July 19, 2021 The quantum Hall effect is the seminal example of topological protection as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. In conventional Hall bar geometries, topological protection of graphene edge channels is found less robust than in high mobility semi-conductors. An international team of researchers (Belgium, Germany, Japan) exploring graphene quantum Hall regime at the local scale revealed that the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels triggering topological breakdown. The finding is a major step forward in the understanding of the quantum Hall effect […]
The era of single-spin color centers in silicon carbide is approaching
Phys.org July 19, 2021 The spin color centers in silicon carbide, including silicon vacancies and divacancies have excellent optical and spin properties. Researchers in China have presented the coherent manipulation of single divacancy spins in 4H-SiC with a high readout contrast (−30%) and a high photon count rate under ambient conditions, which are competitive with the nitrogen-vacancy centres in diamond. Coupling between a single defect spin and a nearby nuclear spin is also observed. They provided a theoretical explanation for the high readout contrast by analysing the defect levels and decay paths. Since the high readout contrast is important in […]
Future information technologies: Topological materials for ultrafast spintronics
Phys.org July 16, 2021 To understand how fast excited electrons in the bulk and on the surface of Sb react to the external energy input, and to explore the mechanisms governing their response an international team of researchers (Germany, Russia, Ireland) used time-, spin- and angle-resolved photoemission to femtosecond-laser excitation. The data showed a ‘kink’ structure in transiently occupied energy-momentum dispersion of surface states, which can be interpreted as an increase in effective electron mass. They were able to show that this mass enhancement plays a decisive role in determining the complex interplay in the dynamical behaviors of electrons from […]
Global satellite data shows clouds will amplify global heating
Phys.org July 19, 2021 Researchers in the UK used data from Earth observations and climate model simulations to develop a statistical learning analysis of how clouds respond to changes in the environment. They showed that global cloud feedback is dominated by the sensitivity of clouds to surface temperature and tropospheric stability. Considering changes in just these two factors, they were able to constrain global cloud feedback to 0.43 ± 0.35 W⋅m−2⋅K−1 (90% confidence), implying a robustly amplifying effect of clouds on global warming and only a 0.5% chance of Equilibrium Climate Sensitivity below 2 K. The “cloud feedback” is the […]
Low-cost, sustainable, readily available plasma technology could replace one of the world’s rarest materials
Nanowerk July 19, 2021 An international team of researchers (Australia, China) has developed a plasma-generated, hybrid nanocomposite material which is free of indium. They used high power impulse magnetron sputtering (HiPIMS) technology to deposit the internal WO3 layer and the external Ag/WO3 nanocomposite. High rates of silver ionization in the HiPIMS process and energetic arrival of silver ions on the negatively biased dielectric/metal/dielectric structure enabled their penetration into the external tungsten oxide layer, forming a nanocomposite structure in a single-step process. This nanotechnology-enabled approach allows electrochromic devices to change colour efficiently and rapidly upon a user’s request and offers a […]
Making clean hydrogen is hard, but researchers just solved a major hurdle
Phys.org July 19, 2021 To create electrically conductive paths through a thick silicon dioxide researchers at UT Austin used a technique first deployed in the manufacturing of semiconductor electronic chips. By coating the silicon dioxide layer with a thin film of aluminum and heating the entire structure, arrays of nanoscale “spikes” of aluminum that completely bridge the silicon dioxide layer were created. These can be replaced by nickel or other materials that help catalyze the water-splitting reactions. When illuminated by sunlight, the devices efficiently oxidized water to form oxygen molecules while also generating hydrogen at a separate electrode and exhibited […]
Microbially produced fibers: Stronger than steel, tougher than Kevlar
Phys.org July 21, 2021 A problem associated with recombinant spider silk fiber is the need to create β-nanocrystals, a main component of natural spider silk, which contributes to its strength. Researchers at Washington University redesigned the silk sequence by introducing amyloid sequences that have high tendency to form β-nanocrystals. They created different polymeric amyloid proteins using three well-studied amyloid sequences as representatives. The resulting proteins had less repetitive amino acid sequences than spider silk, making them easier to be produced by engineered bacteria. The longer the protein, the stronger and tougher the resulting fiber. The 128-repeat proteins resulted in a […]
Nanostructures enable record high-harmonic generation
Phys.org July 21, 2021 Resonantly enhanced High harmonic generation (HHG) from hot spots in nanostructures is an attractive route to overcoming the well-known limitations of gases and bulk solids. An international team of researchers (USA – Cornell University, Ohio State University, Singapore) demonstrated an ultra-thin resonant gallium phosphide platform for highly efficient HHG driven by intense mid-infrared laser pulses. The gallium-phosphide material permits harmonics of all orders without reabsorbing them, and the specialized structure can interact with the laser pulse’s entire light spectrum. The enhanced conversion efficiency facilitates single-shot measurements that avoid material damage and pave the way to study […]