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nanotimes News in Brief

12-03 :: March/April 2012

cal Review B Rapid Communications, Volume 85, Issue 12, March 15, 2012, Article 121406(R), DOI:10.1103/ PhysRevB.85.121406:

http://dx.doi.org/10.1103/PhysRevB.85.121406

Image: Left, an atomic force microscope image of the suspended graphene membrane on the copper mesh. On the right, a scanning tunneling microscope image with atomic resolution taken on the suspended gra- phene membrane. The researchers were able to use the scanning tunneling microscope to control the shape, and therefore the electronic properties, of the graphene membrane. © University of Arkansas

Physicists from the University of Arkansas (US) and other institutions have developed a technique that allows them to control the mechanical property, or strain, on freestanding graphene, sheets of carbon one-atom thick suspended over the tops of tiny squares of copper. By controlling the strain on freestanding graphene, they also can control other properties of this important material.

“If you subject graphene to strain, you change its electronic properties,” said physics professor Salva- dor Barraza-Lopez. Strain on freestanding graphene causes the material to behave as if it is in a magne- tic field, even though no magnets are present, a property that scientists will want to exploit – if they can control the mechanical strain.

P. Xu, Yurong Yang, S. D. Barber, M. L. Ackerman, J. K. Schoelz, D. Qi, Igor A. Kornev, Lifeng Dong, L. Bel- laiche, Salvador Barraza-Lopez, and P. M. Thibado: Ato- mic control of strain in freestanding graphene, In: Physi-

Researchers at the German Fraunhofer Institute for Industrial Mathematics ITWM developed a mechanized ultrasound process that can be used for the non-destructive testing of complex com- ponents. The scientists received support from the GL Group (Germanischer Lloyd) and propeller manufacturer Wärtsilä Propulsion Netherlands.

The mobile scanner can be positioned anywhere on the propeller, and, thanks to its suction feet, it can be attached in a horizontal as well as vertical test position. © ITWM Germany

“With our mobile ultrasound test system, we can inspect copper-nickel-aluminum bronzes up to 450 millimeters thick and detect fissures down to a few millimeters in length. Because we emit the