1,721,228 research outputs found
Exploiting optothermal conversion for nanofabrication: site-selective generation of Au/TiO2 inverse opals
No full textPlasmonic Heating-Assisted Transformation of SiO2/Au Core/Shell Nanospheres (Au Nanoshells): Caveats and Opportunities for SERS and Direct Laser Writing
No full textThe selective modification of silica/gold nanospheres (gold nanoshells) driven by plasmonic heating is demonstrated. Direct laser writing and reshaping of nanoshell assemblies can be easily controlled and exploited for nanofabrication purposes. The modified nanoshells exhibit improved surface enhanced Raman scattering, allowing to settle most of the issues related to nanoshell stability under working condition
Towards a performance-aware power capping orchestrator for the Xen hypervisor
No full textIn the last few years, multi-core processors entered into the domain of embedded systems: this, together with virtualization techniques, allows multiple applications to easily run on the same System-on-Chip (SoC). As power consumption remains one of the most impacting costs on any digital system, several approaches have been explored in literature to cope with power caps, trying to maximize the performance of the hosted applications. In this paper, we present some preliminary results and opportunities towards a performanceaware power capping orchestrator for the Xen hypervisor. The proposed solution, called XeMPUPiL, uses the Intel Running Average Power Limit (RAPL) hardware interface to set a strict limit on the processor's power consumption, while a software-level Observe-Decide-Act (ODA) loop performs an exploration of the available resource allocations to find the most power efficient one for the running workload. We show how XeMPUPiL is able to achieve higher performance under different power caps for almost all the different classes of benchmarks analyzed (e.g., CPU-, memory-and IO-bound)
TiO2 : Mo, MoO3 : Ti, TiO+WO3 and TiO : W layer for landfill produced gases sensing
No full textNowadays, monitoring landfill produced gases (LFGs) is a major task for environmental safety of the areas neighboring garbage dumps. The authors have explored a novel approach to this problem. We have tested solid-state chemoresistive gas sensors to detect typical complex organic gases produced by landfill, i.e., carbon sulfide, methyl sulfide and xylene. We have prepared TiO2:Mo, MoO3:Ti, TiO + WO3 and TiO:W mixed-oxides thin films deposited by reactive sputtering and then processed through the selective sublimation technique. The layers gave remarkable response towards carbon disulfide and xylene below the attention level for these gases. (C) 2004 Elsevier B.V. All rights reserved
Gas sensing properties of zinc oxide nanostructures prepared by thermal evaporation
No full textProgress has been achieved in the synthesis, structural characterization and physical properties investigation of nanostructures. We have focused our attention on zinc oxide nanostructures. We report on the growth of ZnO nanostructures using vapour phase technique. We have synthesized, depending on the growth conditions, different nanostructures such as wires and combs of zinc oxide. ZnO nanowires electrical properties have been characterised in presence of different gases, the results highlight remarkable response to acetone and ethanol with detection limits lower than 1 ppm
Synthesis of Cu2O bi-pyramids by reduction of Cu(OH)2 in solution
No full textIn this paper we describe the synthesis of Cu2O bi-pyramids by reduction of Cu(OH)(2) using hydrazine as reducing agent. Copper chloride is used as a precursor to produce copper hydroxide in aqueous solution and the precipitation of the product is controlled by a slow addition of the reducing agent. All the reactions have been carried out at room temperature and atmospheric pressure with high repeatability. The purification process does not require expensive methods since a solid product is obtained from a reaction in liquid phase. Scanning and Transmission electron microscopy characterization showed interesting bi-pyramidal structures of several microns of edge and different sizes. (C) 2009 Elsevier B.V. All rights reserved
Unexpected Resilience of NiFe Catalysts for the Alkaline Oxygen Evolution Reaction
No full textNiFe catalysts have emerged as promising low-cost alternatives to Ir- or Ru-based anodes for water splitting. Despite their potential, their widespread adoption in commercial alkaline electrolyzers is currently hindered by instability and rapid deactivation under real operating conditions. In this study, we investigate the behavior of NiFe (90/10% at.) thin film (similar to 35 nm) electrodes fabricated by supersonic cluster beam deposition as electrocatalysts for the oxygen evolution reaction in alkaline media during prolonged electrochemical activity. In particular, we observed that an exfoliation process occurred, leading to the detachment and dissolution of most (similar to 99%) of the catalyst nanoparticles (NPs) from the electrode surface into the electrolyte. However, upon multiple potential sweeps, a partial NP redeposition occurred. Importantly, we demonstrate the establishment of an equilibrium between the dissolution and readsorption of catalyst NPs from/to the electrode surface, thereby sustaining significant residual catalytic activity
High-precision neural preprocessing for signal analysis of a sensor array
No full textAn array of semiconducting thin-film sensors is used for high-accuracy determination of gas concentrations in a binary mixture of H2S and NO2. For this purpose we developed a newly conceived pre-processing method for data feeding of a standard neural network. Pre-processing exploits dimension compaction of the vectorial signal of the sensor array. This operation is being accomplished by an auxiliary auto-associative network, separately trained from the main one. Our results present unprecedented accuracy even when applied to a validation-data set and appear to be of widespread application
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