The Experts below are selected from a list of 150246 Experts worldwide ranked by ideXlab platform
Jacob Klein - One of the best experts on this subject based on the ideXlab platform.
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viscosity of ultra thin water films confined between hydrophobic or hydrophilic surfaces
Journal of Physics: Condensed Matter, 2002Co-Authors: Uri Raviv, Joseph Frey, Jacob Klein, Suzanne GiassonAbstract:A surface force balance has been used to investigate the viscosity of salt-free (conductivity) water confined between hydrophilic and between hydrophobic surfaces. We examine the process of jump-in, across the last few Nanometres of thin water films, to adhesive contact between the surfaces. We analyse the flow of water out of the gap under slip and no-slip boundary conditions at the confining surfaces. In both cases we find that the effective viscosity of water remains comparable to its bulk value even when it is confined to sub-Nanometre thin films.
Maureen J Lagos - One of the best experts on this subject based on the ideXlab platform.
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vibrational spectroscopy in the electron microscope
Nature, 2014Co-Authors: Ondrej L Krivanek, T C Lovejoy, N Dellby, Toshihiro Aoki, R W Carpenter, Peter Rez, Emmanuel Soignard, Jiangtao Zhu, P E Batson, Maureen J LagosAbstract:Vibrational spectroscopies using infrared radiation, Raman scattering, neutrons, low-energy electrons and inelastic electron tunnelling are powerful techniques that can analyse bonding arrangements, identify chemical compounds and probe many other important properties of materials. The spatial resolution of these spectroscopies is typically one micrometre or more, although it can reach a few tens of Nanometres or even a few angstroms when enhanced by the presence of a sharp metallic tip. If vibrational spectroscopy could be combined with the spatial resolution and flexibility of the transmission electron microscope, it would open up the study of vibrational modes in many different types of nanostructures. Unfortunately, the energy resolution of electron energy loss spectroscopy performed in the electron microscope has until now been too poor to allow such a combination. Recent developments that have improved the attainable energy resolution of electron energy loss spectroscopy in a scanning transmission electron microscope to around ten millielectronvolts now allow vibrational spectroscopy to be carried out in the electron microscope. Here we describe the innovations responsible for the progress, and present examples of applications in inorganic and organic materials, including the detection of hydrogen. We also demonstrate that the vibrational signal has both high- and low-spatial-resolution components, that the first component can be used to map vibrational features at Nanometre-level resolution, and that the second component can be used for analysis carried out with the beam positioned just outside the sample--that is, for 'aloof' spectroscopy that largely avoids radiation damage.
Amal Chabli - One of the best experts on this subject based on the ideXlab platform.
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Drying nano particles solution on an oscillating tip at an air liquid interface: what we can learn, what we can do
Nanoscale Research Letters, 2007Co-Authors: Charlotte Bernard, Cattien Nguyen, Sophie Marsaudon, Anne-marie Bonnot, François Bertin, Jean-pierre Aimé, Raphaël Lévy, Denis Mariolle, Amal ChabliAbstract:Evaporation of fluid at micro and nanometer scale may be used to self-assemble Nanometre-sized particles in suspension. Evaporating process can be used to gently control flow in micro and nanofluidics, thus providing a potential mean to design a fine pattern onto a surface or to functionalize a nanoprobe tip. In this paper, we present an original experimental approach to explore this open and rather virgin domain. We use an oscillating tip at an air liquid interface with a controlled dipping depth of the tip within the range of the micrometer. Also, very small dipping depths of a few ten nanometers were achieved with multi walls carbon nanotubes glued at the tip apex. The liquid is an aqueous solution of functionalized nanoparticles diluted in water. Evaporation of water is the driving force determining the arrangement of nanoparticles on the tip. The results show various nanoparticles deposition patterns, from which the deposits can be classified in two categories. The type of deposit is shown to be strongly dependent on whether or not the triple line is pinned and of the peptide coating of the gold nanoparticle. In order to assess the classification, companion dynamical studies of nanomeniscus and related dissipation processes involved with thinning effects are presented.
Leela Edwin - One of the best experts on this subject based on the ideXlab platform.
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Development of graphene–Nanometre-sized cerium oxide-incorporated aluminium and its electrochemical evaluation
Applied Nanoscience, 2016Co-Authors: P. Muhamed Ashraf, Saly N. Thomas, Leela EdwinAbstract:Graphene–Nanometre-sized cerium oxide-incorporated aluminium was prepared and its electrochemical and surface morphological characteristics were studied. The atomic force micrographs and scanning electron micrographs evaluation highlighted that the graphene and Nanometre-sized cerium oxide in aluminium had decreased the surface roughness and improved the surface morphological characteristics. The graphene: Nanometre-sized cerium oxide (ratios 1:2 or 2:1) with lesser amounts of particle in the matrix showed excellent corrosion resistance in the marine environment as evidenced by linear polarization, electrochemical impedance and weight loss studies. Introduction of graphene in the aluminium matrix showed a barrier separation between the outermost layer and inner layer, increased roughness and increased corrosion. The material is found to be a potential candidate for use in marine environment.
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Corrosion behaviour of Nanometre sized cerium oxide and titanium oxide incorporated aluminium in NaCl solution
Journal of Alloys and Compounds, 2013Co-Authors: P. Muhamed Ashraf, Leela EdwinAbstract:Abstract The study highlights the development of an aluminium matrix composite by incorporating mixture of Nanometre sized cerium oxide and titanium oxide in pure aluminium and its corrosion resistance in marine environment. The mixed Nanometre sized oxides incorporated aluminium exhibited improved microstructure and excellent corrosion resistance. Corrosion resistance depends on the concentration of Nanometre sized titanium oxide. Electrochemical characteristics improved several folds in Nanometre sized mixed oxides incorporated aluminium than micrometre sized oxides incorporated aluminium.
Pierre Fauchais - One of the best experts on this subject based on the ideXlab platform.
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Engineering a new class of thermal spray nano-based microstructures from agglomerated nanostructured particles, suspensions and solutions : an invited review
Journal of Physics D: Applied Physics, 2011Co-Authors: Pierre Fauchais, G. Montavon, B. R. MarpleAbstract:From the pioneering works of McPherson in 1973 who identified Nanometre-sized features in thermal spray conventional alumina coatings (using sprayed particles in the tens of micrometres size range) to the most recent and most advanced work aimed at manufacturing nanostructured coatings from Nanometre-sized feedstock particles, the thermal spray community has been involved with Nanometre-sized features and feedstock for more than 30 years. Both the development of feedstock (especially through cryo-milling, and processes able to manufacture coatings structured at the sub-micrometre or Nanometre sizes, such as micrometre-sized agglomerates made of Nanometre-sized particles for feedstock) and the emergence of thermal spray processes such as suspension and liquid precursor thermal spray techniques have been driven by the need to manufacture coatings with enhanced properties. These techniques result in two different types of coatings: on the one hand, those with a so-called bimodal structure having Nanometre-sized zones embedded within micrometre ones, for which the spray process is similar to that of conventional coatings and on the other hand, sub-micrometre or nanostructured coatings achieved by suspension or solution spraying. Compared with suspension spraying, solution precursor spraying uses molecularly mixed precursors as liquids, avoiding a separate processing route for the preparation of powders and enabling the synthesis of a wide range of oxide powders and coatings. Such coatings are intended for use in various applications ranging from improved thermal barrier layers and wear-resistant surfaces to thin solid electrolytes for solid oxide fuel cell systems, among other numerous applications. Meanwhile these processes are more complex to operate since they are more sensitive to parameter variations compared with conventional thermal spray processes. Progress in this area has resulted from the unique combination of modelling activities, the evolution of diagnostic tools and strategies, and experimental advances that have enabled the development of a wide range of coating structures exhibiting in numerous cases unique properties. Several examples are detailed.
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Innovative and emerging processes in plasma spraying : from micro- to nano-structured coatings
Journal of Physics D: Applied Physics, 2011Co-Authors: Pierre Fauchais, Armelle VardelleAbstract:In the context of Nanometre-sized structured materials and the perspectives of their technological applications, plasma spray technology is developing to master the coating microstructure at a Nanometre scale level. This paper is an attempt to describe (i) the latest advances in the control of the conventional plasma spray process that requires the monitoring of both the plasma jet fluctuation level and particle processing and (ii) the innovative plasma spray processes that have recently emerged. The latter can be ranked in two classes: the processes that use a liquid feedstock where coatings are essentially formed by the impact of molten particles and droplets; and the processes that generally use a powder feedstock where coatings are generated by the condensation of a vapour with possible inclusion of Nanometre-sized particles. Their potential applications are briefly presented and it is concluded that they should develop into viable technologies in the near future.
