排序方式: 共有126条查询结果,搜索用时 15 毫秒
91.
Saikat Sarkar Susobhan Biswas Meng-Sheng Liao Tapas Kar Yildirim Aydogdu Fethi Dagdelen Golam Mostafa Asoke Prasun Chattopadhyay Glenn P.A. Yap Rui-Hua Xie Abu T. Khan Kamalendu Dey 《Polyhedron》2008
To explore the influence of non-covalent weak force interactions, mainly exerted by carboxylic groups, on the formation of supramolecular architectures of transition metal complexes and their electrical conduction processes, a new symmetrical [N4O2] hexadentate Schiff base ligand, 1,8-N-bis(3-carboxy)disalicylidene-3,6-diazaoctane-1,8-diamine, abbreviated to H4fsatrien, and its complexes of Ni(II), Cd(II) and Mn(II) have been synthesized using in situ condensation of the ligand components in the presence of metal ions. The complexes were structurally characterized by elemental analyses, IR, UV–Vis, NMR, ESR, molar conductivity and magnetic measurements. The crystal structures of all the complexes have been determined by a single crystal X-ray diffraction study. The 1-D, 2-D and 3-D networks of the complexes are formed by π–π stacking, C–H?π interactions and mono or bifurcated H-bonding. The electronic structures of the complexes have been examined using the DFT method. Solid-state properties (e.g. electrical conductivity at different temperatures and optical properties) of the Ni(II) and Mn(II) complexes have also been studied and, depending on the temperature, the conductivity of the complexes is found to be insulating and semiconducting (intrinsic and extrinsic) in nature. The optical band gap (Egd) of complexes (1) and (3) is found to be 2.57 and 2.30 eV, respectively. 相似文献
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93.
Fethi Kamışlı 《Transport in Porous Media》2009,80(2):345-371
The flow of an incompressible Newtonian fluid confined in a planar geometry with different wall temperatures filled with a
homogenous and isotropic porous medium is analyzed in terms of determining the unsteady state and steady state velocities,
the temperature and the entropy generation rate as function of the pressure drop, the Darcy number, and the Brinkman number.
The one-dimensional approximate equation in the rectangular Cartesian coordinates governing the flow of a Newtonian fluid
through porous medium is derived by accounting for the order of magnitude of terms as well as accompanying approximations
to the full-blown three-dimensional equations by using scaling arguments. The one-dimensional approximate energy and the entropy
equations with the viscous dissipation consisting of the velocity gradient and the square of velocity are derived by following
the same procedure used in the derivation of velocity expressions. The one-dimensional approximate equations for the velocity,
the temperature, and the entropy generation rate are analytically solved to determine the velocity, the temperature, and the
entropy distributions in the saturated porous medium as functions of the effective process parameters. It is found that the
pressure drop, the Darcy number, and the Brinkman number affect the temperature distribution in the similar way, and besides
the above parameters, the irreversibility distribution ratio also affects the entropy generation rate in the similar way. 相似文献
94.
Amandine Calmet Abdelilah Amar Sophie Griveau Virginie Lair Eliane Sutter Francisco Javier Recio Philippe Brunswick Fethi Bedioui Michel Cassir 《Electroanalysis》2016,28(2):380-384
A non‐invasive device based on measurements of electrochemical skin conductance can detect small fiber neuropathy, a sweat gland dysfunction implicated in several diseases. The measurement is related to sweat composition and notably to chloride concentration. To optimize the electrode material, in vitro experiments are performed in mimetic sweat solutions. This work reports on the resistance to pitting corrosion of biocompatible stainless steels (AISI 304L, AISI 430, AISI 430T, D2205) in sweat mimicking electrolyte at pH 7 with variable chloride concentration, to determine the most sensitive material to sweat composition. AISI 430 is promising due to its high sensitivity to chloride concentration variations. 相似文献
95.
Journal of Thermal Analysis and Calorimetry - In this study, some thermal, mechanical, and magnetic properties of Co86Al14 and Co82Al14Cr4 (at.%) alloys have been investigated. The alloys were... 相似文献
96.
In this study, the numerical models for swirling flows developed by Li et al and Zhou for lattice Boltzmann method (LBM) are chosen. These models were firstly validated using the Couette-Taylor flow between two concentric cylinders simulations. Numerical results showed the efficiency of the Zhou's model. Numerical simulation results using LBM are in good agreement for the steady and unsteady regimes compared to the literature review. In a second step, the Zhou model was then adopted to our study to determine the Couette-Taylor instabilities with an axial flow. Two protocols are tested. The first one (direct protocol) starts with an azimuthal flow without any axial flow (Re = 0). Once the regime is established, an axial flow is then superposed to the Couette-Taylor flow (with a sudden or a progressive manner). The second protocol (inverse protocol) starts with an axial flow at a given Reynolds number (Poiseuille flow). Once the regime is established, an azimuthal flow is the executed (with a sudden or a progressive manner). The effect of various parameters controlling the physical situation is also discussed. The increase of the azimuthal velocity mainly led to the emergence and development of Taylor vortices. Its influence decreases when the axial Reynolds number increases. The relevant result for this study is the change of the critical axial Reynolds number Rec (total disappearance of instabilities) with both protocols and both manners. 相似文献
97.
Fethi Soltani 《Acta Mathematica Hungarica》2014,142(2):433-443
We use the Fourier analysis associated to a singular second-order differential operator Δ, and prove a continuous-time principle for the L p theory. 相似文献
98.
In this paper we critically review detection limits of electrochemical DNA biosensors enabling DNA detection without target labelling. The review includes transduction principles and latest breakthroughs. To compare the efficiency of each type of electrochemical DNA biosensor, a simple DNA biosensors classification is established on the basis of the nature of the bio-electrochemical transduction. 相似文献
99.
Nabil Dakhli Fethi Choubani Jacques David 《Applied Physics A: Materials Science & Processing》2011,103(3):525-527
A novel resonant metamaterial antenna based on the Composite Right/Left-Handed (CRLH) transmission line (TL) model is presented.
The proposed small antenna is designed to operate simultaneously over multiple wireless services (UMTS-WLAN-WIMAX) 相似文献
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