Search results for "D.N.A."
showing 10 items of 6568 documents
Mechanical characterisation of pentagonal gold nanowires in three different test configurations: A comparative study.
2019
Abstract Mechanical characterisation of individual nanostructures is a challenging task and can greatly benefit from the utilisation of several alternative approaches to increase the reliability of results. In the present work, we have measured and compared the elastic modulus of five-fold twinned gold nanowires (NWs) with atomic force microscopy (AFM) indentation in three different test configurations: three-point bending with fixed ends, three-point bending with free ends and cantilevered-beam bending. The free-ends condition was realized by introducing a novel approach where the NW is placed diagonally inside an inverted pyramid chemically etched in a silicon wafer. In addition, all thre…
Determination of refractive index of submicron-thick films using resonance shift in a four-layer slab waveguide
2017
The measurement of refractive index of very thin films at the order of ten to hundred nanometers is cumbersome and usually requires employing sophisticated techniques such as the spectral ellipsometry. In this paper we describe a simple contact method for measuring the refractive index of thin films. Here we have used the prism-coupling technique for characterizing samples prepared as four-layer slab waveguides. The waveguide resonance condition can be calculated by solving simple analytic transcendental equations for the slab waveguide. Then the captured mode position as a function of cladding thickness is used for probing the refractive index of cladding layer. We used indium-tin-oxide la…
Depth profiles of damage creation and hardening in MgO irradiated with GeV heavy ions
2019
This work has been performed within the framework of the EUROfusion Enabling Research project: ENR-MFE19.ISSP-UL-02 “Advanced experimental and theoretical analysis of defect evolution and structural disordering in optical and dielectric materials for fusion applications”. The views and opinions expressed herein do not necessarily reflect those of the European Commission.
Strain detection in non-magnetic steel by Kerr-microscopy of magnetic tracer layers
2018
Abstract For many applications of steel, e.g. for the evaluation of the fatigue state of components or structures, the characterization of the microscopic strain distribution in the material is important. We present a proof-of-principle for the visualization of such strain distributions by Kerr-microscopy of ferromagnetic tracer layers on nonmagnetic steel sheets. The influence of indentation induced strain on the magnetic domain pattern of 20 nm Galfenol and Permalloy tracer layers on austenitic AISI 904L steel sheets was investigated. The obtained Kerr-microscopy images show a characteristic domain pattern in the strained regions of the steel sheets, which is consistent with a dominant ma…
Determination of elastoplastic properties of TiO2 thin films deposited on dual phase stainless steel using nanoindentation tests
2010
International audience; In recent years, the extraction of mechanical behaviour of thin films by nanoindentation using sharp indenter geometry has been extensively studied. This work investigates the mechanical properties of TiO2 thin film (1 µm thickness) deposited by spin coating on dual phase Duplex stainless steel and glass substrates. Experiments are carried out with different sharp triangular pyramids (a Cube corner and a Berkovich indenter) using a commercial Nano Indenter® XP apparatus. The substrate effect has been counteracted and an inverse method proposed in literature for bulk material has been adapted to assess the elastoplastic parameters of the tested thin film directly from…
Atomic layer deposition of aluminum oxide on modified steel substrates
2016
Abstract Al 2 O 3 thin films were grown by atomic layer deposition to thicknesses ranging from 10 to 90 nm on flexible steel substrates at 300 °C using Al(CH 3 ) 3 and H 2 O as precursors. The films grown to thicknesses 9–90 nm covered the rough steel surfaces uniformly, allowing reliable evaluation of their dielectric permittivity and electrical current densities with appreciable contact yield. Mechanical behavior of the coatings was evaluated by nanoindentation. The maximum hardness values of the Al 2 O 3 films on steel reached 12 GPa and the elastic modulus exceeded 280 GPa.
Catalytic epoxidation using dioxidomolybdenum(VI) complexes with tridentate aminoalcohol phenol ligands
2019
Reaction of the tridentate aminoalcohol phenol ligands 2,4-di-tert-butyl-6-(((2 hydroxyethyl)(methyl)amino)methyl)phenol (H2L1) and 2,4-di-tert-butyl-6-(((1-hydroxybutan-2-yl)amino)methyl)phenol (H2L2) with [MoO2(acac)2] in methanol solutions resulted in the formation of [MoO2(L1)(MeOH)] (1) and [MoO2(L2)(MeOH)] (3), respectively. In contrast, the analogous reactions in acetonitrile afforded the dinuclear complexes [Mo2O2(μ-O)2(L1)2] (2) and [Mo2O2(μ-O)2(L2)2] (4). The corresponding reactions with the potentially tetradentate ligand 3-((3,5-di-tert-butyl-2-hydroxybenzyl)(methyl)amino)propane-1,2-diol (H3L3) led to the formation of the mononuclear complex [MoO2(L3)(MeOH)] (5) in methanol whi…
Encapsulation and solid state sequestration of gases by calix[6]arene-based molecular containers
2017
Two calix[6]arene-based molecular containers were synthesized in high yields. These containers can encapsulate small guests through a unique "rotating door" complexation process. The sequestration of greenhouse gases is clearly demonstrated. They can be stored in the solid state for long periods and released via dissolution of the inclusion complex.
Acceptorless dehydrogenative condensation: synthesis of indoles and quinolines from diols and anilines.
2021
The use of diols and anilines as reagents for the preparation of indoles represents a challenge in organic synthesis. By means of acceptorless dehydrogenative condensation, heterocycles, such as indoles, can be obtained. Herein we present an experimental and theoretical study for this purpose employing heterogeneous catalysts Pt/Al2O3 and ZnO in combination with an acid catalyst (p-TSA) and NMP as solvent. Under our optimized conditions, the diol excess has been reduced down to 2 equivalents. This represents a major advance, and allows the use of other diols. 2,3-Butanediol or 1,2-cyclohexanediol has been employed affording 2,3-dimethyl indoles and tetrahydrocarbazoles. In addition, 1,3-pro…
A new chiral dimanganese(iii) complex: synthesis, crystal structure, spectroscopic, magnetic, and catalytic properties
2016
Two enantiomeric complexes of formula [MnIII2(μ-OCH3)2(R-valBINAM)2]·1.75DMF (1) and [MnIII2(μ-OCH3)2(S-valBINAM)2]·2DMF (2) [valBINAM = 1,1′-binaphthalene-2,2′-bis(3-methoxysalicylideneiminate)] have been synthesized using as a ligand the chiral Schiff bases resulting from the condensation reactions between o-vanillin and the chiral 1,1′-binaphthyl-2,2′-diamine. The structures of 1 and 2 which have been solved by single crystal X-ray diffraction consist of neutral dimers, the manganese(III) ions being bridged by two methoxido anions, arising from the solvent, and by two valBINAM2− ligands. Their circular dichroism spectra at room temperature emphasize the occurrence of the exciton coupling…