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An aqueous biphasic system has been used for selective extraction of U(VI) ions from Th(IV), Sm(III) and Ce(III). Role of different biomolecules like morin, catechin, hesperidin and 4-hydroxycoumarin have been studied. Morin serves as the best reagent when citrate ions are used as a masking agent. Citrate forms stronger complexes with the other metal ions than morin thereby restricting their extractions. Contrarily, U(VI) forms a stronger complex with morin than citrate and is selectively extracted under the same conditions. It was also observed that morin can act as a spectrophotometric reagent for ratiometric detection and analysis of U(VI) ions.

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The transamination reaction of 2,5-diaminobenzoquinonediimine (QDI) with ethylenediamine gave fluorescent 1,2,3,4-tetrahydropyrazino[2,3-g]quinoxaline (1). When the same reaction was carried out with N,N’-bis(aminoethyl)-1,3-propanediamine, a novel cationic quinoxalinium species (2) was isolated, which can be further condensed with p-cyanobenzaldehyde to afford a benzimidazolo-fused quinoxaline dye (3) that is a water-soluble fluorophore in the UV–visible range.  相似文献   
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The chemical functionalization of carbon nanotubes is often a prerequisite prior to their use in various applications. The covalent grafting of 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (BPin) functional groups directly on the surface of multi- and single-walled carbon nanotubes, activated by nucleophilic addition of nBuLi, was carried out. Thermogravimetric analysis (TGA) coupled with mass spectrometry, Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ions mass spectrometry (ToF-SIMS) confirmed the efficiency of this methodology and proved the integrity and covalent grafting of the BPin functional groups. These groups were further reacted with various nucleophiles in the presence of a copper(II) source in the conditions of the aerobic Chan–Lam–Evans coupling. The resulting materials were characterized by TGA, XPS and ToF-SIMS. This route is efficient, reliable and among the scarce reactions that enable the direct grafting of heteroatoms at carbonaceous material surfaces.  相似文献   
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The interaction of Love waves with square array of pillars deposited on a cavity defined in a 2D holey phononic crystal is numerically investigated using Finite Element Method. First, the existence of SH surface modes is demonstrated separately for phononic crystals that consist of square arrayed holes, or rectangular arrayed Ni pillars, respectively in, or on, a SiO2 film deposited on a ST-cut quartz substrate. The coupling between SH modes and torsional mode in pillars induces a transmission dip that occurs at a frequency located in the range of the band-gap of the holey phononic crystal. Second, a cavity is constructed by removing lines of holes in the holey phononic crystal and results in a transmission peak that matches the dip. The optimal geometrical parameters enable us to create a coupling of the cavity mode and the localized pillar mode by introducing lines of pillars into the cavity, which significantly improved the efficiency of the cavity without increasing the crystal size. The obtained results will pave the way to implement advanced designs of high-performance electroacoustic sensors based on coupling modes in phononic crystals.  相似文献   
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A multi-physics simulation combining large-eddy simulation, conjugate heat transfer and radiative heat transfer is used to predict the wall temperature field of a confined premixed swirling flame operating under atmospheric pressure. The combustion model accounts for the effect of enthalpy defect on the flame structure whose stabilization is here sensitive to the wall heat losses. The conjugate heat transfer is accounted for by solving the heat conduction within the combustor walls and with the Hybrid-Cell Neumann-Dirichlet coupling method, enabling to dynamically adapt the coupling period. The latter coupling procedure is enhanced to determine statistics (mean, RMS, \(\ldots \)) in a permanent regime accurately and efficiently thanks to an acceleration technique which is derived and validated. The exact radiative heat transfer equation is solved with an advanced Monte Carlo method with a local control of the statistical error. The coupled simulation is carried out with or without accounting for radiation. Excellent results for the wall temperature are achieved by the fully coupled simulation which are then further analyzed in terms of radiative effects, global energy budget and fluctuations of wall heat flux and temperature.  相似文献   
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Theoretical and Computational Fluid Dynamics - The aerodynamic characteristics of two neighboring airfoils are greatly different from those of a single airfoil, for both attached and detached flow...  相似文献   
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