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51.
Clément Ghiazza Moussa Ndiaye Anfal Hamdi Anis Tlili Thierry Billard 《Tetrahedron》2018,74(45):6521-6526
Herein, the direct C-5 fluoroalkylselenolation of 8-aminoquinolines is described. The Pd-catalyzed reaction is performed with the in situ generated fluoroalkylselenyl chloride and various 8-aminoquinoline amides or sulfonamides. The desired products were formed in moderate to excellent yields. 相似文献
52.
Hamdi Ben Halima Abdelhamid Errachid Nicole Jaffrezic-Renault 《Electroanalysis》2023,35(1):e202100451
The review presents advances and main challenges of the affinity sensors based on field- effect transistors published during the last five years. The different nanomaterial-based field-effect transistors are classified according to the nature of the nanomaterials, beginning by silicon, the “gold-standard” semiconductor, the gallium nitride semiconductor, the organic semiconductors, the silicon nanowires, the inorganic nanomaterials, the carbon nanotubes and the graphene. Due to its exceptional electrical properties, the main works are devoted to graphene. The obtained analytical performances for the detection of biomarkers, of DNA sequences and of miRNA are listed. The relation between the operational conditions - nature of the nanomaterials, procedure of preparation, choice of the receptor molecule, method of immobilization – and the analytical performance are discussed. The perspective of industrialization of these affinity sensors based on field-effect transistors is discussed. 相似文献
53.
Abdelwaheb Hamdi Young Hoon Lee Dewi K.A. Kusumahastuti Rym Abidi 《Tetrahedron letters》2009,50(5):540-551
The synthesis and complexation properties of a novel type of calix[4]azacrown, in which two cone calix[4]arenes are linked via a spiro C-atom incorporated into polyaminoalkylene chains are presented. 相似文献
54.
Hamdi Raïssi 《Comptes Rendus Mathematique》2011,349(21-22):1203-1206
This Note is devoted to the test of instantaneous linear Granger causality when the errors are dependent but uncorrelated. The assumptions are weak and include a large set of dynamics as for instance the GARCH processes. We show that the standard Wald test for testing instantaneous linear Granger causality is not valid in our framework. As a consequence Wald tests which are valid in our framework are proposed. 相似文献
55.
56.
This Note deals with the boundary null-controllability of linear diffusion–reaction equations in a 2D bounded domain. We transform the determination of the sought HUM boundary control into the minimization of a continuous and strictly convex functional. In the case of a rectangular domain where the diffusion tensor is represented by a diagonal matrix, we establish a procedure based on the inner product method that uses a complete orthonormal family of Sturm–Liouville's eigenfunctions to express explicitly the sought control. 相似文献
57.
This paper investigates quasi-periodic vibration-based energy harvesting in a delayed nonlinear MEMS device consisting of a delayed Mathieu–van der Pol–Duffing type oscillator coupled to a delayed piezoelectric coupling mechanism. We use the multiple scales method to approximate the quasi-periodic response and the related power output near the principal parametric resonance. The effect of time delay on the energy harvesting performance is studied. It is shown that for appropriate combination of time delay parameters, there exists an optimum range of excitation frequency beyond the resonance where quasi-periodic vibration-based energy harvesting is maximum. Numerical simulations are performed to confirm the analytical predictions. 相似文献
58.
Patrick Jenny Hamdi A. Tchelepi Seong H. Lee 《Journal of computational physics》2009,228(20):7497-7512
This paper addresses the convergence properties of implicit numerical solution algorithms for nonlinear hyperbolic transport problems. It is shown that the Newton–Raphson (NR) method converges for any time step size, if the flux function is convex, concave, or linear, which is, in general, the case for CFD problems. In some problems, e.g., multiphase flow in porous media, the nonlinear flux function is S-shaped (not uniformly convex or concave); as a result, a standard NR iteration can diverge for large time steps, even if an implicit discretization scheme is used to solve the nonlinear system of equations. In practice, when such convergence difficulties are encountered, the current time step is cut, previous iterations are discarded, a smaller time step size is tried, and the NR process is repeated. The criteria for time step cutting and selection are usually based on heuristics that limit the allowable change in the solution over a time step and/or NR iteration. Here, we propose a simple modification to the NR iteration scheme for conservation laws with S-shaped flux functions that converges for any time step size. The new scheme allows one to choose the time step size based on accuracy consideration only without worrying about the convergence behavior of the nonlinear solver. The proposed method can be implemented in an existing simulator, e.g., for CO2 sequestration or reservoir flow modeling, quite easily. The numerical analysis is confirmed with simulation studies using various test cases of nonlinear multiphase transport in porous media. The analysis and numerical experiments demonstrate that the modified scheme allows for the use of arbitrarily large time steps for this class of problems. 相似文献
59.
Jacques Darriet Hamdi Ben Yahia Etienne Gaudin 《Acta Crystallographica. Section C, Structural Chemistry》2005,61(7):i79-i80
Single crystals of sodium tetracalcium trivanadium dodecaoxide were prepared by melting a powder sample of NaCa4(VO4)3 at 1673 K, followed by slow cooling to room temperature. The compound crystallizes in the Pnma space group and is isostructural with the mineral silicocarnotite, Ca5(PO4)2SiO4. The structure is composed of isolated VO4 tetrahedra linked by sodium and calcium cations disordered over eight‐ and seven‐coordinated sites. 相似文献
60.
A new fluorogenic calix[4]tetraaza-crown-6 (4) bearing two pyrene amide groups has been prepared. It was shown to be selective for Mg2+. When Mg2+ is bound to 4, the pyrene monomer emission increased while the excimer emission declined in a ratiometric manner. It is shown by 1H NMR that this ratiometric change is due to the conformational changes of the pyrenes during the chelation of Mg2+ by the amide functions to form a 1:1 complex. 相似文献