Nanowerk August 24, 2022 As it is difficult to determine whether the currently used polymeric coatings applied to the surfaces of automobiles, ships, etc. to protect them from the external environment are already damaged or not, these non-reusable coatings must be regularly replaced, leading to a large amount of waste generation and high disposal costs. Researchers in South Korea have demonstrated mechanochromic and thermally reprocessable thermosets that can be used for autonomic damage reporting and self-healing coatings. A mechanochromic molecule, spiropyran (SP), was covalently incorporated into thermoreversible Diels–Alder (DA) cross-linking networks. Mechanical activation of SPs in DA networks was confirmed […]
Engineers fabricate a chip-free, wireless electronic ‘skin’
MIT News August 18, 2022 Flexible electronic materials (e-skins) can be limited by the need to include rigid components. A range of techniques have emerged to bypass this problem, including approaches for wireless communication and charging based on silicon, carbon nanotubes, or conducting polymers. An international team of researchers (USA – MIT, University of Virginia, South Korea) has developed a chip-less wireless e-skin based on surface acoustic wave sensors made of freestanding ultrathin single-crystalline piezoelectric gallium nitride membranes. It offers highly sensitive, low-power, and long-term sensing of strain, ultraviolet light, and ion concentrations in sweat. They demonstrated weeklong monitoring of […]
Exploring quantum electron highways with laser light
Nanowerk August 18, 2022 The phase transition between non-trivial and trivial topological states is important for next-generation technology, such as dissipation-free electronics. A team of researchers in the US (SLAC National Accelerator Laboratory, Stanford University, Harvard University, the State University of New Jersey) has demonstrated that circularly polarized laser-field-driven high-harmonic generation is distinctly sensitive to the non-trivial and trivial topological phases in the prototypical three-dimensional topological insulator bismuth selenide. The phase transition is chemically initiated by reducing the spin–orbit interaction strength through the substitution of bismuth with indium atoms. The phase transition is chemically initiated by reducing the spin–orbit interaction […]
Harvesting energy – drop by drop
Nanowerk August 25, 2022 In this review article researchers in China summarized the recent developments in droplets-driven nanogenerators for effective energy scavenging. They included an extensive discussion about the device structures from the material selection and output performance aspects. They gave a brief discussion on the applications of droplet-based nanogenerators and outline the future possibilities via the current improvement in designs and fabrication strategies that have been introduced by the field. According to the authors water droplet harvesting as a sustainable energy resource has become a forward-looking step to meet the future demand for green energy. The emerging potential of […]
Lack of grants from funding agencies biggest barrier to OA publishing in physical sciences, study finds
Phys.org August 22, 2022 AIP Publishing, the American Physical Society (APS), IOP Publishing (IOPP) and Optica Publishing Group (formerly OSA) conducted a study on Open Access (OA). Over 3,000 physical science researchers from across the globe participated in the OA in physics. According to the study over half (53%) of physical science researchers want to publish OA but 62% say a lack of monies from funding agencies prevents them from doing so. Over the past 5 years, 14% of respondents have not published OA at all, and over 50% have only published one article per year OA over that period. […]
New evidence that water separates into two different liquids at low temperatures
Phys.org August 19, 2022 The first-order phase transition between two tetrahedral networks of different density has received strong support from a growing body of work in recent years. An international team of researchers (UK, Italy) showed that this liquid–liquid phase transition in tetrahedral networks can be described as a transition between an unentangled, low-density liquid and an entangled, high-density liquid, the latter containing an ensemble of topologically complex motifs. They first revealed this distinction in a rationally designed colloidal analogue of water. They showed that this colloidal water model displays the well-known water thermodynamic anomalies as well as a liquid–liquid […]
New stable quantum batteries can reliably store energy into electromagnetic fields
Phys.org August 24, 2022 An international team of researchers (Italy, South Korea) revisited micromaser, a quantum mechanical system, that has been studied heavily in the past. They showed that micromasers have features that allow them to serve as excellent models of quantum batteries. However, one of the main concerns was that using electromagnetic field to store energy is that in principle, the electromagnetic field could absorb an enormous amount of energy. But their numerical results showed that this cannot happen in micromasers, the electromagnetic field reaches a steady state, and its energy can be determined and decided a priori when […]
Novel smart material enables high-performance and reliable light control of droplets
Nanowerk August 24, 2022 Light control of droplets enables remote and contactless control with remarkable spatial and temporal accuracy. However, their performance, and reliability are challenging. Researchers in China have developed a new smart material with photo-induced charge regeneration capability, enabling light control of droplets with superior performance and reliability. The smart material contains three core components: micro-size liquid metal particles with superior photothermal and thermally conductive properties; polyvinylidene fluoride trifluoroethylene copolymer with excellent ferroelectric and mechanical behaviors; and micro-pyramidal structures and low-surface-energy coatings of fluorinated SiO2 nanoparticles for enhancing the superamphiphobicity. The photo-induced charged surfaces (PICSs) possess a superior […]
A quantum pump without a crank
Phys.org August 22, 2022 The pumping process can have topological origins, when considering the motion of quantum particles in spatially and temporally periodic potentials. However, the periodic evolution that drives these pumps has always been assumed to be imparted from outside. Researchers in Switzerland found an emergent mechanism for pumping in a quantum gas coupled to an optical resonator, where they observed a particle current without applying a periodic drive. The pumping potential experienced by the atoms is formed by the self-consistent cavity field interfering with the static laser field driving the atoms. The cavity field evolves between its two […]
Researchers discover a material that can learn like the brain
Nanowerk August 22, 2022 MOS junctions can provide a variety of functionalities, from memory to computing. The technology, however, faces constraints in terms of further miniaturization and compatibility with post–von Neumann computing architectures. Manipulation of structural—rather than electronic—states could provide a path to ultrascaled low-power functional devices, but the electrical control of such states is challenging. An international team of researchers (Switzerland, South Korea) report electronically accessible long-lived structural states in vanadium dioxide that can provide a scheme for data storage and processing. The states can be arbitrarily manipulated on short timescales and tracked beyond 10,000 s after excitation, exhibiting features […]