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70 nanotimes News in Brief
"Dr. Koratkar is conducting pioneering, high-impact work in graphene that is helping solidify the international reputation of Rensselaer in the field of nanomaterials. Nikhil is also an outstanding educator, adviser, and mentor who cares deeply about the success of his students," said David Rosowsky, dean of the School of Engineering at Rensselaer. "The entire School of Engineering joins me in congratulating him on his appointment as the Clark and Crossan Professor of Engineering."
http://homepages.rpi.edu/~koratn/
IMAGE: Maxi Bellmann, researcher at the Institute for Print and Media Technology of Chemnitz University of Technology, shows the printed loudspeaker area. The bottom side of the paper loudspeaker can be printed with advertising messages – in this case you can see the logos of the project partners. © Hendrik Schmidt
The Institute for Print and Media Technology at Chemnitz University of Technology, Germany, presents printed loudspeakers on paper substrate. The printed paper loudspeaker is connected to an audio amplifier like a conventional loudspeaker. "Frequency response and hence sound quality are very good and the paper is surprisingly loud. Just the bass of the paper-based loudspeaker is a bit weak," explains Dr. Georg Schmidt, senior researcher at pmTUC. The thin loudspeakers, which are printed in the laboratories of pmTUC, contain several layers of a conductive organic polymer and a piezoactive layer.
Researchers from the Institute of Physical Chemistry of the Polish Academy of Sciences in Warsaw, and the Interdisciplinary Research Institute in Lille developed a low cost method for manufacturing multilayered graphene sheets. The new method does not require any specialized equipment and can be implemented in any laboratory.
The new process for producing graphene sheets starts with graphite, one of carbon allotrope, on the molecular level resembling a sandwich composed of many graphene planes. These sheets are hardly separable. To weaken interactions between them, graphite must be oxidized, which is usually accomplished with the Hummers method. A powder obtained in that way – graphite oxide – is subsequently suspended in water and placed in an ultrasonic cleaner. The ultrasounds exfoliate oxidized graphene sheets from each other and the resulting colloid contains single graphene oxide flakes with diameter of about 300nm.