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Dense WC-x vol% cobalt (5 ≤ x ≤ 20) composites, with WC grain size of ∼1 µm, were synthesized by field-activated and pressureassisted combustion synthesis (FAPACS) within several minutes from elemental powders. Simultaneous synthesis and densification were accomplished under the combined effects of an electric field and mechanical pressure. The effect of cobalt content on the hardness, fracture toughness, and relative density of dense WC-x vol% cobalt composites was investigated. The relative density of the WC-cobalt composites increased with increased cobalt content. Under the application of a 60 MPa pressure and a 3000 A current, the final products had relatively high densities, 99.4%, for WC-20 vol% cobalt. The hardness of the WC-cobalt composites decreased with increased cobalt content, while the fracture toughness increased. The maximum fracture toughness and hardness values obtained were 9.4 MPa·m[sup ½] for the WC-20lvol % cobalt composition and 2014 kg·mm[sup -2] for the WC-5 vol% cobalt composition. [ABSTRACT FROM AUTHOR]

The article reports on the scannable lens that is capable of an improved resolution developed by Allard Mosk and his colleagues in Amsterdam as of June 2011. The exploitation of the random scattering behavior of a strongly disordered surface rather than a polished surface of a lens is described to be responsible for the improved resolution. The lens and imaging process used by Mosk and his team is detailed. The author suggests extending the scan range and simplifying the sample placement and modulator tuning for the lens' future success.

Raman spectra of large graphene bubbles showed size-dependent oscillations in spectral intensity and frequency, which originate from optical standing waves formed in the vicinity of the graphene surface. At a high laser power, local heating can lead to oscillations in the Raman frequency and also create a temperature gradient in the bubble. Based on Raman data, the temperature distribution within the graphene bubble was calculated, and it is shown that the heating effect of the laser is reduced when moving from the center of a bubble to its edge. By studying graphene bubbles, both the thermal conductivity and chemical reactivity of graphene were assessed. When exposed to hydrogen plasma, areas with bubbles are found to be more reactive than flat graphene. [ABSTRACT FROM AUTHOR]

Few-layer graphenes, supported on Si with a superficial oxide layer, were subjected to a Birch-type reduction using Li and H 2 O as the electron and proton donors, respectively. The extent of hydrogenation for bilayer graphene was estimated at 1.6-24.1% according to Raman and X-ray photoelectron spectroscopic data. While single-layer graphene reacts uniformly, few-layer graphenes were hydrogenated inward from the edges and/or defects. The role of these reactive sites was reflected in the inertness of pristine few-layer graphenes whose edges were sealed. Hydrogenation of labeled bilayer ( 12 C/ 13 C) and trilayer ( 12 C/ 13 C/ 12 C) graphenes afforded products whose sheets were hydrogenated to the same extent, implicating passage of reagents between the graphene layers and equal decoration of each graphene face. The reduction of few-layer graphenes introduces strain, allows tuning of optical transmission and fluorescence, and opens synthetic routes to long sought-after films containing sp 3 -hybridized carbon.