Often touted as a wonder material, graphene is a one-atom thick layer of carbon with remarkable, record breaking properties. Until now its ability to absorb electromagnetic radiation – energy from across the radio frequency spectrum – was not known.
Publishing in the journal Scientific Reports, the scientists demonstrated that the transparent material increased the absorption of electromagnetic energy by 90 per cent at a wide bandwidth.
"The technological potential of graphene is well-known. This paper demonstrates one example of how that potential can translate into a practical application," said Yang Hao, co-author of the study and Professor of Antennas and Electromagnetics at Queen Mary's School of Electronic Engineering and Computer Science.
"The transparent material could be added as a coating to car windows or buildings to stop radio waves from travelling through the structure. This, in turn, could be used to improve secure wireless network environments, for example."
The researchers placed a stack of layers of graphene supported by a metal plate and the mineral quartz to absorb the signals from a millimetre wave source, which allows the efficient control of wave propagation in complex environments.
Co-author Bian Wu, who is at Queen Mary from Xidian University in China on a scholarship from China Scholarship Council, added: "The stacking configuration gives us better control of the interaction between radio waves and the graphene."
The group is now developing prototypes like wireless networks, which are aimed to take the graphene from lab-based research to engineering applications.
Sian Halkyard | EurekAlert!
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Controlling electronic current is essential to modern electronics, as data and signals are transferred by streams of electrons which are controlled at high speed. Demands on transmission speeds are also increasing as technology develops. Scientists from the Chair of Laser Physics and the Chair of Applied Physics at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have succeeded in switching on a current with a desired direction in graphene using a single laser pulse within a femtosecond ¬¬ – a femtosecond corresponds to the millionth part of a billionth of a second. This is more than a thousand times faster compared to the most efficient transistors today.
Graphene is up to the job
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
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Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
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Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
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