Phys.org August 31, 2023 Thermoresponsive graphene-oxide (GO) nanosheets have been widely employed to develop smart membranes/surfaces, hydrogel actuators, recyclable systems, and biomedical applications. Current synthetic strategies to generate thermoresponsive GO nanosheets have exclusively relied on the covalent or non-covalent modification of their surfaces with thermoresponsive polymers. Researchers in Japan discovered that GO nanosheets with Bu4N+ countercations became thermoresponsive in water without the use of any thermoresponsive polymers, inducing a reversible sol–gel transition via their self-assembly and disassembly processes. The resultant dispersion can be used as a direct writing ink for constructing a three-dimensionally designable gel architecture of the GO nanosheets. […]
Device offers long-distance, low-power underwater communication
MIT News September 6, 2023 Researchers at MIT have designed, evaluated, and implemented Van Atta Acoustic Backscatter (VAB), a technology that enables long-range, ultra-low-power networking in underwater environments. VAB is scalable underwater backscatter architecture that bridges recent advances in RF backscatter (Van Atta architectures) with ultra-low-power underwater acoustic networks. Their design introduces multiple innovations across the networking stack to overcome unique challenges that arise from the electro-mechanical properties of underwater backscatter and the challenging nature of low-power underwater acoustic channels. They implemented and evaluated their design in over 1,500 real-world experimental trials in a river and the ocean. In stationary […]
Growing triple-decker hybrid crystals for lasers
Phys.org August 31, 2023 Although two-dimensional organic semiconductor-incorporated perovskites are a promising family of hybrid materials for optoelectronic applications, tuning their structures and specific properties has remained challenging. By choosing the right solvent a team of researchers in the US (Purdue University, Duke University, Lawrence Berkeley National Laboratory) has developed a general method to tune the dimensionality of phase-pure organic semiconductor-incorporated perovskite single crystals during their synthesis. They showed that the length of the conjugated semiconducting organic cations and the dimensionality of the inorganic layers could be manipulated at the same time. The energy band offsets and exciton dynamics at […]
Linking two solar technologies is a win-win for efficiency and stability
Nanowerk September 5, 2023 Although metal halide perovskites have rapidly enabled a range of high-performance photovoltaic technologies, their catastrophic failure under reverse voltage bias poses a roadblock for their commercialization. An international team of researchers (Princeton University, Saudi Arabia) conducted a series of stress tests to compare the reverse-bias stability of perovskite single-junction, silicon single-junction, and monolithic perovskite/silicon tandem solar cells. They demonstrated that the tested perovskite/silicon tandem devices were considerably more resilient against reverse bias compared with perovskite single-junction devices. The origin of such improved stability stemmed from the low reverse-bias diode current of the silicon subcell. This translated […]
Mapping Australia’s hidden lithium reserves
Phys.org August 31, 2023 Researchers in Australia used a digital soil mapping framework to combine data from recent geochemical surveys and environmental covariates that affect soil formation to predict and map aqua-regia-extractable Li content across the 7.6×106 km2 area of Australia. Catchment outlet sediment samples were collected with both top (0–10 cm depth) and bottom (on average ∼60–80 cm depth). They developed 50 bootstrap models using a cubist regression tree algorithm for each depth. The spatial prediction models were validated on an independent Northern Australia Geochemical Survey dataset, showing a good prediction for the top depth. The model for the bottom depth is […]
Missile Defense Agency Sees Megawatt Anti-ICBM Lasers by 2026
Next Big Future September 5, 2023 The Pentagon has been spending about $1 billion per year researching directed energy weapons like lasers and microwave weapons for decades. They have bought a few demonstration systems for Navy ships and mounted on trucks. In July 2023 Lockheed Martin announced they will scale its laser technology to a new benchmark: a 500 kW-class laser. This is the second phase of the High Energy Laser Scaling Initiative. After spending tens of billions on combat laser research over the past few decades, they are finally seeing some real progress to usable combat lasers in the […]
Novel titanium dioxide catalyst shows promise for electrocatalytic carbon dioxide reduction
Phys.org September 5, 2023 CO2 can be selectively reduced by gold, lead, etc. supported on conductive carbon. However, the high pH in the vicinity of the electrode raises concerns about the catalyst and catalyst support degradation. Researchers in Japan used chemically stable titanium dioxide (TiO2) powder as an alternative to carbon. TiO2 maintained its particle shape and crystalline structure after in-liquid plasma treatment was used to improve its electrochemical properties. When its electrochemical properties were evaluated, they observed the disappearance of Ti4+ and Ti3+ redox peaks derived from TiO2 and a decrease in hydrogen overvoltage. The hydrogen overvoltage relationship suggested […]
Out with the old, in with the new: Agile mentorship to support future scientists
Phys.com August 31, 2023 Existing mentorship models are limited by miscommunication, undefined roles, and mismatched goals. To address these limitations a team of researchers in the US (Mayo Clinic, Indiana University) leveraged insights from agile science and the existing evidence on effective mentorship models to support effective mentoring relationships in healthcare environments. They described the model and shared qualitative findings generated from the independent analysis of 18 months of mentee reflections. In two iterative cycles, reflections (n = 56) were analyzed using exploratory content and relational analysis and identified four main themes – identification of shortcomings, adaptive perspective, managing relationships, and personal […]
Scientists demonstrate new, improved way to make infrared light, with quantum dots
Phys.org September 6, 2023 In the visible spectrum, electroluminescence from colloidal quantum dots is highly efficient, wavelength tunable and cost effective, which motivates using the same approach in the infrared. Despite the promising performances of colloidal quantum dots light-emitting diodes in the near-infrared, mid-infrared devices show quantum efficiencies of about 0.1% due to the much weaker emission. These devices relied exclusively on the interband transition, restricting the possible materials. Researchers at the University of Chicago showed electroluminescence at 5 µm using the intraband transition between 1Se and 1Pe states within the conduction band of core–shell HgSe–CdSe colloidal quantum dots. The 4.5% […]
Scientists develop an energy-efficient wireless power and information transfer system
Science Daily September 5, 2023 A simultaneous wireless information and power transfer (SWIPT)-enabled nonorthogonal multiple access (NOMA) system has been recognized as a promising technology for enabling the Industrial Internet of Things (IIoT), as it extends the lifetime of small battery-driven sensors. However, its energy efficiency significantly decreases with distance from the central controller. Researchers in South Korea proposed a framework for applying SWIPT-aided NOMA system to a distributed antenna system (DAS) to improve the spectral efficiency and energy efficiency of the IIoT. They optimized the power allocation for the NOMA signaling and power splitting for SWIPT in the DAS […]