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81.
Mirzaei M Saeed J 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):351-354
A selective and sensitive chemosensor, based on the 2(4-hydroxy pent-3-en-2-ylideneamine) phenol (HPYAP) as chromophore, has been developed for colorimetric and visual detection of Ag(I) ions. HPYAP shows a considerable chromogenic behavior toward Ag(I) ions by changing the color of the solution from pale-yellow to very chromatic-yellow, which can be easily detected with the naked-eye. The chemosensor exhibited selective absorbance enhancement to Ag(I) ions in water samples over other metal ions at 438 nm, with a linear range of 0.4–500 μM (r2 = 0.999) and a limit of detection 0.07 μM of Ag(I) ions with UV–vis spectrophotometer detection. The relative standard deviation (RSD) for 100 μM Ag(I) ions was 2.05% (n = 7). The proposed method was applied for the determination Ag(I) ions in water and waste water samples. 相似文献
82.
Numerical results of two-dimensional elastic phase-field simulations of martensitic phase transformations (fcc-bcc) in polycystals are presented. The stresses and strains in the diffuse interface domain are described by following Khachaturyan's approach of microelasticity. A fixed-point iteration algorithm in Fourier space is used to solve the mechanical equilibrium condition for the microscopic, inhomogeneous strain field and apply mechanical loadings to the system. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
83.
The tungstic acid-catalyzed reaction of ketals with hydrogen peroxide provides a convenient and efficient method for preparing gem-dihydroperoxides. 相似文献
84.
Recoverable salen-based macrocyclic chiral complexes; catalysts for enantioselective Henry reactions
Farah Ibrahim Nada Jaber Vincent Guérineau Ali Hachem Ghassan Ibrahim Mohamed Mellah Emmanuelle Schulz 《Tetrahedron: Asymmetry》2013,24(21-22):1395-1401
Cobalt and chromium complexes have been prepared from chiral calix–salen cyclic ligands. The corresponding tetrahydrosalen reduced forms have been used for copper salt complexation. These new chiral catalysts have been tested for their ability to promote asymmetric Henry reactions between various aldehydes and nitromethane under heterogeneous conditions. The best results were obtained by using tetrahydrosalen-based copper macrocycles, in terms of activity, selectivity, and stability during the recycling process. Ten consecutive runs could indeed be performed with the same catalyst batch to produce the target 1-(2-methoxy-phenyl)-2-nitro-ethanol with highly stable values in terms of yield and enantioselectivity (up to 94% ee). 相似文献
85.
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87.
Eduardo Abi Jaber Bruno Bouchard Camille Illand 《Stochastic Processes and their Applications》2019,129(5):1726-1748
This paper provides a new characterization of the stochastic invariance of a closed subset of with respect to a diffusion. We extend the well-known inward pointing Stratonovich drift condition to the case where the diffusion matrix can fail to be differentiable: we only assume that the covariance matrix is. In particular, our result can be applied to construct affine and polynomial diffusions on any arbitrary closed set. 相似文献
88.
Walid Al-Maksoud Julien Mesnager Farouk Jaber Catherine Pinel Laurent Djakovitch 《Journal of organometallic chemistry》2009,694(20):3222-3231
Pd-catalysed procedures for the direct Heck arylation of diethyl vinylphosphonate with various aryl or heteroaryl halides toward the synthesis of diethyl 2-(aryl)vinylphosphonates are reported. Several homogeneous catalytic systems (i.e. Herrmann palladacycle, Nolan (NHC)-palladium catalyst, Pd(OAc)2/PPh3) were used and compared within the study. High conversions and selectivities were achieved under optimised conditions (2 mol% [Pd], NMP, K2CO3, 140 °C) whatever the homogeneous catalyst used. 相似文献
89.
Mohamad Jaber Al-Jeboori Hasan Ahmad Hasan Worood A. Jaafer Al-Sa’idy 《Transition Metal Chemistry》2009,34(6):593-598
The new multidentate Schiff-base (E)-6,6′-((1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(methan-1-yl-ylidene))bis(4-methyl-2-((E)(pyridine-2-ylmethylimino)methyl)phenol) H2L and its polymeric binuclear metal complexes with Cr(III), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)
are reported. The reaction of 2,6-diformyl-4-methyl-phenol with ethylenediamine in mole ratios of 2:1 gave the precursor 3,3′-(1E,1′E)-(ethane-1,2-diylbis(azan-1-yl-1ylidene))bis(methan-1-yl-1-ylidene)bis(2-hydroxy-5-methylbenzaldehyde) W. Condensation of the precursor with 2-(amino-methyl)pyridine in mole ratios of 1:2 gave
the new N6O2 multidentate Schiff-base ligand H2L. Upon complex formation, the ligand behaves as a dibasic octadentate species with the involvement of the nitrogen atoms
of the pyridine groups in coordination for all complexes. The mode of bonding and overall geometry of the complexes were determined
through physico-chemical and spectroscopic methods. These studies revealed octahedral geometries for Cr(III), Mn(II), Fe(II),
Co(II), Ni(II), Cu(II), Cd(II) and Hg(II) complexes of general formulae [Cr2III(L)Cl2]Cl2, [Ni2II(L)(H2O)2]Cl2 and [M2(L)Cl2] and five co-ordinate Zn(II) complex of general formula [Zn2II(L)]Cl2. 相似文献
90.
This paper presents a new predictive model of droplet flow and heat transfer from molten salt droplets in a direct contact heat exchanger. The process is designed to recover heat from molten CuCl in a thermochemical copper–chlorine (Cu–Cl) cycle of hydrogen production. This heat recovery occurs through the physical interaction between high temperature CuCl droplets and air. Convective heat transfer between droplets and air is analyzed in a counter-current spray flow heat exchanger. Numerical results for the variations of temperature, velocity and heat transfer rate are presented for two cases of CuCl flow. The optimal dimensions of the heat exchanger are found to be a diameter of 0.13 m, with a height of 0.6 and 0.8 m, for 1 and 0.5 mm droplet diameters, respectively. Additional results are presented and discussed for the heat transfer effectiveness and droplet solidification during heat recovery from the molten CuCl droplets. 相似文献