Recent results of the searches for Supersymmetry in final states with one or two leptons at CMS are presented. Many Supersymmetry scenarios, including the Constrained Minimal Supersymmetric extension of the Standard Model (CMSSM), predict a substantial amount of events containing leptons, while the largest fraction of Standard Model background events -which are QCD interactions -gets strongly reduced by requiring isolated leptons. The analyzed data was taken in 2011 and corresponds to an integrated luminosity of approximately L = 1 fb −1 . The center-of-mass energy of the pp collisions was √ s = 7 TeV.

Blends of reduced graphene oxide (RGO) and poly(3-hexylthiophene) (P3HT) are used as the active layer of field-effect transistors (FETs). By using sequential deposition of the two components, the density of RGO sheets can be tuned linearly, thereby modulating their contribution to the charge transport in the transistors, and the onset of charge percolation. The surface potential of RGO, P3HT and source-drain contacts is measured on the nanometric scale with Kelvin Probe Force Microscopy (KPFM), and correlated with the macroscopic performance of the FETs. KPFM is also used to monitor the potential decay along the channel in the working FETs.

Conductive atomic force microscopy (C-AFM) has been used to correlate the detailed structural and electrical characteristics of graphene derived from graphene oxide. Uniform large currents were measured over areas exceeding tens of micrometers in few-layer films, supporting the use of graphene as a transparent electrode material. Moreover, defects such as electrical discontinuities were easily detected. Multilayer films were found to have a higher conductivity per layer than single layers. It is also shown that a local AFM-tip-induced electrochemical reduction process can be used to pattern conductive pathways on otherwise-insulating graphene oxide. Transistors with micrometer-scale tip-reduced graphene channels that featured ambipolar transport and an 8 order of magnitude increase in current density upon reduction were successfully fabricated.

While the unique elastic properties of monolayer graphene have been extensively investigated, less knowledge has been developed so far on folded graphene. Nevertheless, it has been recently suggested that fold-induced curvature (without in-plane strain) could possibly affect the local chemical and electron transport properties of graphene, envisaging a material-by-design approach where tailored membranes are used in enhanced nanoresonators or nanoelectromechanical devices. In this work we propose a novel method combining apparent strain analysis from high-resolution transmission electron microscopy (HREM) images and theoretical modeling based on continuum elasticity theory and tight-binding atomistic simulations to map and measure the nanoscale curvature of graphene folds and wrinkles. If enough contrast and resolution in HREM images are obtained, this method can be successfully applied to provide a complete nanoscale geometrical and physical picture of 3D structure of various wrinkle and fold configurations.

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A new Micro-Opto-Mechanical System (MOMS) technology for the fabrication of optoacoustic probes on optical fiber is presented. The technology is based on the thermoelastic emission of ultrasonic waves from patterned carbon films for generation and on extrinsic polymer Fabry-Perot acousto-optical transducers for detection, both fabricated on miniaturized single-crystal silicon frames used to mount the ultrasonic transducers on the tip of an optical fiber. Thanks to the fabrication process adopted, high miniaturization levels are reached in the MOMS devices, demonstrating fiber-optic emitters and detectors with minimum diameter around 350 and 250 μm respectively. A thorough functional testing of the ultrasound emitters mounted on 200 and 600 μm diameter optical fibers is presented, in which the fiber-optic emitter with a diameter of 200 μm shows generated acoustic pressures with peak-to-peak value up to 2.8 MPa with rather flat emission spectra extended beyond 150 MHz. The possibility to use the presented optoacoustic sources in conjunction with the fiber-optic acousto-optical detectors within a minimally invasive probe is also demonstrated by successfully measuring the ultrasonic echo reflected from a rigid surface immersed in water with various concentration of scatterers. The resulting spectra highlight the possibility to discriminate the effects due to frequency selective attenuation in a very wide range of frequencies within a biological medium using the presented fiber-optic probes.

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In this work, we report on the fabrication and characterization of organic light-emitting transistors (OLETs) within an indium−tin-oxide (ITO)free platform, using graphene-based transparent conductive electrodes in place of ITO as gate electrode. A direct comparison between twin bottom-gate/topcontacts OLETs, where a standard ITO layer is replaced with a film made of a few graphene layers, shows that comparable electrical characteristics can be obtained along with a clear improvement in the electroluminescence generation characteristics. Our experimental findings pave the way to the exploitation of graphene-based transparent conductive electrodes within this class of emerging devices on flexible substrates, further promoting the novel era of flexible organic electronics.