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48


nanotimes News in Brief


results are consistent with those of recent graphene experiments by other research groups but provide new quantitative data.


Most significantly, the NIST study shows why friction falls with each sheet of graphene added to the stack (fast scanning also has an effect on the friction). With fewer layers, the top layer deflects more, and the friction per unit of AFM contact force rises. The top surface of the stack becomes less yielding and more slippery as graphene layers are added.


12-01 :: January 2012


By contrast, the friction of three-dimensional gra- phite-like material is virtually unaffected by deforma- tion and rolling friction, and is due instead to heat created by the moving tip.


A. Smolyanitsky, J.P. Killgore and V.K. Tewary: Effect of elastic deformation on frictional properties of few-layer graphene, In: Physical Review B, Volume 85(2012), Issue 3, January 09, 2012, Article 035412 [6 pages], DOI:10.1103/ PhysRevB.85.035412:


http://dx.doi.org/10.1103/PhysRevB.85.035412


Crystals // A New Kind of High-Temperature Photonic Crystal


materials called photonic crystals, using metals such as tungsten or tantalum. The new materials can operate at temperatures up to 1200° C (2192° F). NASA has taken an interest in the research because of its potential to provide long-term power for deep- space missions that cannot rely on solar power.


A


Yi Xiang Yenga, Michael Ghebrebrhan, Peter Bermel, Wal- ker R. Chan, John D. Joannopoulos, Marin Soljačić, Ivan Celanovic: Enabling high-temperature nanophotonics for energy applications, In: PNAS Early Edition, January 23, 2012, DOI:10.1073/pnas.1120149109: http://dx.doi.org/10.1073/pnas.1120149109


team of MIT researchers has developed a way of making a high-temperature version of a kind of


Image: A microscope image of the tungsten photonic crystal structure reveals the precise uniform spacing of cavities formed in the material, which are tuned to specific wavelengths of light. © Y.X. Yeng et al.


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