11-10 :: October 2011

nanotimes News in Brief

a tiny silicon structure within an optomechanical system can effectively store information without the aid of steady power supply – thus serving as a mechanical memory device.

Mahmood Bagheri, Menno Poot, Mo Li, Wolfram P. H. Pernice & Hong X. Tang: Dynamic manipulation of nano- mechanical resonators in the high-amplitude regime and non-volatile mechanical memory operation, In: Nature Nanotechnology AOP, October 23, 2011, DOI:10.1038/ nnano.2011.180:

http://dx.doi.org/10.1038/nnano.2011.180

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ceable was that when CNTs are added to the algae suspension, its color darkens and the algae forms clumps with the nanotubes. Despite this there is no evidence that the nanotubes are absorbed by the plants.

The investigators came to the conclusion, therefore, that the algae grow more slowly because they stick together as a result of the presence of CNTs and therefore receive less light.

F. Schwab, T.D. Bucheli, L.P. Lukhele, A. Magrez, B. No- wack, L. Sigg, K. Knauer: Are Carbon Nanotube Effects on Green Algae Caused by Shading and Agglomeration? In: Environmental Science & Technology, Vol. 45(2011), Issue 14, Pages 6136-6144, DOI:10.1021/es200506b: http://dx.doi.org/10.1021/es200506b

An interdisciplinary team of scientists from Empa (CH) and the Agroscope Reckenholz-Tae- nikon (ART) Research Station have begun investiga- ting the fundamentals of how CNTs behave when they are deposited in waterways and lakes. Now, this Empa study shows that while CNTs do not have toxic effects on green algae they do inhibit its growth by depriving the plant of light and space.

In the course of the project, which is financed by the Swiss National Funds, researchers further developed a standard chemical method in order to measure the growth and photosynthetic activity of green algae exposed to CNTs. They discovered that even in the presence of high concentrations of CNTs the algae retain normal levels of photosynthe- sis, although growth rates are reduced. Also noti-

Scientists at the Advanced Technology Institute of the University of Surrey (U.K.) have demonstrated a new semiconducting phase of graphene formed by the self-organisation of hydrogen atoms on its surface. At high levels of hydrogen adsorption, the British researchers have shown self-assembly and ordering of the hydrogen atoms forming a structure akin to a C4

H polymer. The analysis also shows an

upper limit to the amount of hydrogen which can be stored by chemisorption under the applied con- ditions. Calculation of the electronic bandstructure of this new material reveals a wide-gap semicon- ductor with potential applications for UV photonics.

Danny Haberer, Cristina E. Giusca, Ying Wang, Her- mann Sachdev, Alexander V. Fedorov, Mani Farjam, S.