A research group led by Prof. Li Runwei at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS) have proposed a "slight cross-linking" method that imparts elastic recovery to ferroelectric materials. The study was published in Science.
Ferroelectric materials are very useful for applications such as data storage and processing, sensing, energy conversion, and optoelectronics, etc., making them highly desirable in mobile phones, tablets and other electronic devices for everyday use.
After stress is relieved, however, conventional ferroelectric materials exhibit poor elastic recovery—typically less than 2%, thus tend to be either brittle (ferroelectric ceramics) or plastic (ferroelectric polymers).
The ferroelectric properties of these materials are mainly due to their crystalline regions, which lack intrinsic elasticity.
To solve the dilemma of ferroelectric response and elastic recovery, the researchers developed a precise "slight cross-linking" method.
Obtaining useful work from random fluctuations in a system at thermal equilibrium has long been considered impossible. In fact, in the 1960s eminent American physicist Richard Feynman effectively shut down further inquiry after he argued in a series of lectures that Brownian motion, or the thermal motion of atoms, cannot perform useful work.
Now, a new study published in Physical Review E titled "Charging capacitors from thermal fluctuations using diodes" has proven that Feynman missed something important.
Three of the paper's five authors are from the University of Arkansas Department of Physics. According to first author Paul Thibado, their study rigorously proves that thermal fluctuations of freestanding graphene, when connected to a circuit with diodes having nonlinear resistance and storage capacitors, does produce useful work by charging the storage capacitors.
The authors found that when the storage capacitors have an initial charge of zero, the circuit draws power from the thermal environment to charge them.
The team then showed that the system satisfies both the first and second laws of thermodynamics throughout the charging process. They also found that larger storage capacitors yield more stored charge and that a smaller graphene capacitance provides both a higher initial rate of charging and a longer time to discharge. These characteristics are important because they allow time to disconnect the storage capacitors from the energy harvesting circuit before the net charge is lost.
This latest publication builds on two of the group's previous studies. The first was published in a 2016 Physical Review Letters. In that study, Thibado and his co-authors identified the unique vibrational properties of graphene and its potential for energy harvesting.
A University of Massachusetts Amherst biomedical engineer has used a nanogel-based carrier designed in his lab to deliver a drug exclusively to the liver of obese mice, effectively reversing their diet-induced disease.
"The treated mice completely lost their gained weight, and we did not see any untoward side effects," says S. Thai Thayumanavan, distinguished professor of chemistry and biomedical engineering. "Considering 100 million Americans have obesity and related cardiometabolic disorders, we became pretty excited about this work."
Efforts to translate these findings to humans are being pursued by a start-up company Cyta Therapeutics, which was founded at the UMass Institute for Applied Life Sciences (IALS) based on the nanogel technologies from the Thayumanavan lab. In late July, Cyta Therapeutics won the Judges' Choice Best Startup at the 16th annual Massachusetts Life Sciences Innovation (MALSI) Day in Boston.
Vivid displays, enriched color variations and boosted stability are something everyone can look forward to encountering as advances are made in the electrochromic device (ECD) field
Electrochromic devices (ECDs) are useful in controlling optical properties such as reflection and absorption and are particularly pertinent when it comes to use in smart windows, rearview mirrors and adaptive camouflage. Unfortunately, the widely used electrochromic materials show a lackluster display with minimal color changes and poor cycling stability, often only transforming between transparency and a single color with sluggish switching speeds.
This study demonstrates the use of a more compatible component in the form of a highly porous tin oxide (SnO2) nanosheet scaffold, which provides better cycling, more color variations and a seamless performance than what the current technology has to offer.
Researchers published their work in Nano Research.
A new self-assembling nanosheet could radically accelerate the development of functional and sustainable nanomaterials for electronics, energy storage, health and safety, and more.
Developed by a team led by Lawrence Berkeley National Laboratory (Berkeley Lab), the new self-assembling nanosheet could significantly extend the shelf life of consumer products. And because the new material is recyclable, it could also enable a sustainable manufacturing approach that keeps single-use packaging and electronics out of landfills.
The team is the first to successfully develop a multipurpose, high-performance barrier material from self-assembling nanosheets. The breakthrough was reported in Nature.
"Our work overcomes a longstanding hurdle in nanoscience—scaling up nanomaterial synthesis into useful materials for manufacturing and commercial applications," said Ting Xu, the principal investigator who led the study. "It's really exciting because this has been decades in the making."
Xu is a faculty senior scientist in Berkeley Lab's Materials Sciences Division, and a professor of chemistry and materials science and engineering at UC Berkeley.
One challenge in harvesting nanoscience to create functional materials is that many small pieces need to come together so that the nanomaterial can grow large enough to be useful. While stacking nanosheets is one of the simplest ways to grow nanomaterials into a product, "stacking defects"—gaps between the nanosheets—are unavoidable when working with existing nanosheets or nanoplatelets.
Vanderbilt mechanical engineering professors Deyu Li and Josh Caldwell are part of a team of researchers who have discovered a new heat dissipation channel using phonon polaritons that could have extensive implications for novel cooling technologies in devices like smart phones and other modern electronics.
The research was recently published in Nature under the title "Remarkable Heat Conduction Mediated by Non-equilibrium Phonon Polaritons."
It is well known that electrons and atomic vibrations (phonons) are the major energy carriers in solids. Research teams from Vanderbilt University and Oak Ridge National Laboratory (ORNL) were surprised to find that surface phonon polaritons, hybrid quasi-particles resulting from coupling between infrared light and optically active phonons, could contribute significantly to heat conduction in thin films and nanowires of polar crystals.
An advancement in neutron shielding, a critical aspect of radiation protection, has been achieved. This breakthrough is poised to revolutionize the neutron shielding industry by offering a cost-effective solution applicable to a wide range of materials surfaces.
A research team, led by Professor Soon-Yong Kwon in the Graduate School of Semiconductors Materials and Devices Engineering and the Department of Materials Science and Engineering at UNIST has successfully developed a neutron shielding film capable of blocking neutrons present in radiation. This innovative shield is not only available in large areas but also lightweight and flexible.
The team's paper is published in the journal Nature Communications.
"The developed MXene-Boron carbide composite shielding film is several tens of micrometers thick, over 1,000 times thinner than conventional commercial materials," noted Professor Kwon. "It can be effortlessly applied to various surfaces, resembling the act of painting."
Neutrons, which are integral to nuclear power generation, medical devices, and aerospace industries, possess inherent dangers when leaked. They can trigger unexpected phenomena in electronic devices or living organisms through interactions with other atoms.
When Emiliano Cortés goes hunting for sunlight, he doesn't use gigantic mirrors or sprawling solar farms. Quite the contrary, the professor of experimental physics and energy conversion at LMU dives into the nanocosmos.
"Where the high-energy particles of sunlight, the photons, meet atomic structures is where our research begins," Cortés says. "We are working on material solutions to capture and use solar energy more efficiently."
His findings have great potential as they enable novel solar cells and photocatalysts. The industry has high hopes for the latter because they can make light energy accessible for chemical reactions—bypassing the need to generate electricity. But there is one major challenge to using sunlight, which solar cells also have to contend with, Cortés knows: "Sunlight arrives on Earth 'diluted,' so the energy per area is comparatively low." Solar panels compensate for this by covering large areas.
Researchers at the University of Manchester have made a breakthrough in the transfer of 2D crystals, paving the way for their commercialization in next-generation electronics. This technique, detailed in a recent Nature Electronics article, utilizes a fully inorganic stamp to create the cleanest and most uniform 2D material stacks to date.
The team, led by Professor Roman Gorbachev from the National Graphene Institute, employed the inorganic stamp to precisely "pick and place" 2D crystals into van der Waals heterostructures of up to eight individual layers within an ultra-high vacuum environment. This advancement resulted in atomically clean interfaces over extended areas, a significant leap forward compared to existing techniques and a crucial step towards the commercialization of 2D material-based electronic devices.
Moreover, the rigidity of the new stamp design effectively minimized strain inhomogeneity in assembled stacks. The team observed a remarkable decrease in local variation—over an order of magnitude—at "twisted" interfaces, when compared to current state-of-the-art assemblies.
Ammonia (NH3) is regarded as a promising carbon-free energy carrier, but its energy-intensive production process still challenges global scientists. A research team led by City University of Hong Kong (CityU) recently engineered a bimetallic alloy as an ultrathin nanocatalyst that can deliver greatly improved electrochemical performance for generating ammonia from nitrate (NO3-), offering great potential for obtaining carbon-neutral fuel in the future.
The findings were published in the journal the Proceedings of the National Academy of Sciences (PNAS) under the title "Atomic coordination environment engineering of bimetallic alloy nanostructures for efficient ammonia electrosynthesis from nitrate."
Ammonia, which is commonly used in fertilizer, has recently attracted a lot of attention because it can provide a source of hydrogen for fuel cells, and it is easier to liquefy and transport than hydrogen. Owing to its huge demand, upcycling nitrate (NO3-) from ammonium fertilizer-polluted wastewater has emerged as an alternative for reproducing valuable ammonia and making agriculture more sustainable.
Currently, electrochemical nitrate reduction reaction (NO3RR) is regarded as a promising solution for ammonia synthesis. It comprises mainly deoxygenation and hydrogenation steps (i.e. NO3- + 9H+ + 8e- ➙ NH3 + 3H2O) with metal-based electrocatalysts.
