DJL

Publication date: June 2015
Source:Tribology International, Volume 86
Author(s): Carlos M.C.G. Fernandes , Pedro M.T. Marques , Ramiro C. Martins , Jorge H.O. Seabra
The film thickness and the traction curves of four fully formulated wind turbine gear oils were measured on a ball-on-disc device. All oils have the same viscosity grade (ISO VG 320) and different formulations: ester, mineral, PAO and mineral+PAMA. Film thickness and traction coefficient results will be presented. The film thickness measurements were compared with predictions using film thickness equations from the literature.

Publication date: 1 April 2015
Source:Journal of Crystal Growth, Volume 415
Author(s): Punarja Kevin , David J. Lewis , James Raftery , M. Azad Malik , Paul O’Brien
The synthesis of the asymmetric dithiocarbamates of tin(II) with the formula [Sn(S2CNRR׳)2] (where R=Et, R׳=n-Bu (1); R=Me, R׳=n-Bu (2); R=R׳=Et (3)) and their use for the deposition of SnS thin films by aerosol-assisted chemical vapour deposition (AACVD) is described. The effects of temperature and the concentration of the precursors on deposition were investigated. The stoichiometry of SnS was best at higher concentrations of precursors (250mM) and at 450°C. The direct electronic band gap of the SnS produced by this method was estimated from optical absorbance measurements as 1.2eV. The composition of films was confirmed by powder X-ray diffraction (p-XRD) and energy dispersive analysis of X-rays (EDAX) spectroscopy.

Nature Nanotechnology. doi:10.1038/nnano.2015.10

Author: Guy Le Lay

Artificially synthesized silicene — an atomically thin layer of silicon — is set to rival natural layered materials in the development of field-effect transistors.

Nature Nanotechnology. doi:10.1038/nnano.2014.325

Authors: Li Tao, Eugenio Cinquanta, Daniele Chiappe, Carlo Grazianetti, Marco Fanciulli, Madan Dubey, Alessandro Molle & Deji Akinwande

Free-standing silicene, a silicon analogue of graphene, has a buckled honeycomb lattice and, because of its Dirac bandstructure combined with its sensitive surface, offers the potential for a widely tunable two-dimensional monolayer, where external fields and interface interactions can be exploited to influence fundamental properties such as bandgap and band character for future nanoelectronic devices. The quantum spin Hall effect, chiral superconductivity, giant magnetoresistance and various exotic field-dependent states have been predicted in monolayer silicene. Despite recent progress regarding the epitaxial synthesis of silicene and investigation of its electronic properties, to date there has been no report of experimental silicene devices because of its air stability issue. Here, we report a silicene field-effect transistor, corroborating theoretical expectations regarding its ambipolar Dirac charge transport, with a measured room-temperature mobility of ∼100 cm2 V–1 s–1 attributed to acoustic phonon-limited transport and grain boundary scattering. These results are enabled by a growth–transfer–fabrication process that we have devised—silicene encapsulated delamination with native electrodes. This approach addresses a major challenge for material preservation of silicene during transfer and device fabrication and is applicable to other air-sensitive two-dimensional materials such as germanene and phosphorene. Silicene's allotropic affinity with bulk silicon and its low-temperature synthesis compared with graphene or alternative two-dimensional semiconductors suggest a more direct integration with ubiquitous semiconductor technology.

Article

Nanobubbles in liquid phase are puzzling, because their internal pressure is estimated to be unphysically large. Here, Shin et al . visualize the dynamics of nanobubbles in water encapsulated by graphene membrane and show fast gas diffusion through ultrathin water layer between two coalescing bubbles.

Nature Communications doi: 10.1038/ncomms7068

Authors: Dongha Shin, Jong Bo Park, Yong-Jin Kim, Sang Jin Kim, Jin Hyoun Kang, Bora Lee, Sung-Pyo Cho, Byung Hee Hong, Konstantin S Novoselov

Nature Nanotechnology. doi:10.1038/nnano.2014.323

Authors: Yijun Yu, Fangyuan Yang, Xiu Fang Lu, Ya Jun Yan, Yong-Heum Cho, Liguo Ma, Xiaohai Niu, Sejoong Kim, Young-Woo Son, Donglai Feng, Shiyan Li, Sang-Wook Cheong, Xian Hui Chen & Yuanbo Zhang

Abstract