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991.
S. El Helali K. Daoudi A. Fouzri M. Oumezzine M. Oueslati T. Tsuchiya 《Applied Physics A: Materials Science & Processing》2012,108(2):379-384
We have studied the structural and electrical properties of epitaxial La0.7Ca0.3MnO3 (LCMO) thin films prepared by metal organic deposition under different types and degrees of substrate-induced strain. 40-nm-thick films have been epitaxially grown on single-crystalline (LaAlO3)0.3?C(SrAlTaO6)0.7 (negligible tensile strain), SrTiO3 (tensile strain) and LaAlO3 (compressive strain) substrates. High-resolution X-ray diffraction and reciprocal space maps demonstrate a direct correlation between the crystalline quality and the substrate-induced strain. The electrical properties were found to be strongly dependent on the substrate used. The temperature dependence of resistivity curves was fitted using various approaches in different phases (below and above the ferromagnetic transition temperature T P). In the ferromagnetic metallic phase, ??(T) follows a T ?? power law. The obtained values of the coefficient ???(3.5?C4) indicate that the electrical transport in our films is a combination of spin wave scattering processes and electron?Cmagnon or two-magnon scattering phenomena. In the paramagnetic insulator phase, the activation energy E A and the variable range hopping characteristics (characteristic temperature T 0) were found to be strongly dependent on the strain-induced lattice mismatch between the LCMO and the substrate used. 相似文献
992.
Ahmed El Kharroubi Abdelhak Yaacoubi Abdelghani Ben Tahar Kawtar Bichard 《Queueing Systems》2012,70(4):299-337
In this paper we consider the variational problem in the non-negative orthant of ℝ3. The solution of this problem gives the large deviation rate function for the stationary distribution of an SRBM (Semimartingal
Reflecting Brownian Motion). Avram, Dai and Hasenbein (Queueing Syst. 37, 259–289, 2001) provided an explicit solution of this problem in the non-negative quadrant. Building on this work, we characterize reflective
faces of the non-negative orthant of ℝ
d
, we construct boundary influence cones and we provide an explicit solution of several constrained variational problems in ℝ3. Moreover, we give conditions under which certain spiraling paths to a point on an axis have a cost which is strictly less
than the cost of every direct path and path with two pieces. 相似文献
993.
Kissi Benaissa Parron Vera Miguel Angel Rubio Cintas Maria Dlolores Dubujet Philippe Khamlichi Abdellatif Bezzazi Mohammed El Bakkali Larbi 《Applied Mathematical Modelling》2012
CFD simulation with enhanced modeling of turbulence and near-wall treatment is used to model water–clay mixtures flowing through a cylindrical pipe domain. Effects on the wall-shear stress resulting from varying water clay content and applied hydraulic gradient are analyzed. Various parametric studies were performed and had shown that the two-dimensional modelling introduced in the present study does not yield a uniform wall-shear stress along the pipe wall and that clay concentration affects significantly the wall-shear stress value. This is in contrast with the common hypothesis used in one-dimensional modeling approaches where this stress is assumed constant and which gives rise to uniform erosion along the pipe wall. The obtained results had enabled predicting more realistically erosion amount and had allowed for understanding the irregular eroded hole wall shape as observed experimentally after performing the standard hole erosion test. 相似文献
994.
Kheira Diaf Zineb El Bahri Nafa Chafi Lahcen Belarbi Abderrezzak Mesli 《Chemical Papers》2012,66(8):779-786
The present paper provides details of the preparation of polymeric tablets and microspheres based on piroxicam as a therapeutic active agent and the drug release study from these formulations. Tablets composed of ethylcellulose, Eudragit? or mixtures of Eudragit? and synthesised poly(oxepan-2-one) were prepared and tested. The effect of the matrix on the drug release at 37°C was studied. The drug-loaded microparticles were prepared using solvent evaporation microencapsulation. These systems were characterised by SEM and FTIR spectroscopy and the size and size distribution were also determined. The results demonstrated that the drug release could be modified by means of these formulations. Finally, piroxicam dissolution rate constants were calculated from Higuchi??s release model. 相似文献
995.
Azab HA Duerkop A Mogahed EM Awad FK Abd El Aal RM Kamel RM 《Journal of fluorescence》2012,22(2):659-676
This work describes the application of time resolved fluorescence in microtiterplates and electrochemical methods on glassy
carbon electrode for investigating the interactions of europium-3-carboxycoumarin with pesticides aldicarb, methomyl and prometryne.
Stern-volmer studies at different temperatures indicate that static quenching dominates for methomyl, aldicarb and prometryne.
By using Lineweaver-Burk equation binding constants were determined at 303 K, 308 K and 313 K. A thermodynamic analysis showed
that the reaction is spontaneous with ΔG being negative. The enthalpy ΔH and the entropy ΔS of reactions were all determined.
A time-resolved (gated) luminescence-based method for determination of pesticides in microtiterplate format using the long-lived
europium-3-carboxycoumarin has been developed. The limit of detection is 4.80, 5.06 and 8.01 μmol L−1 for methomyl, prometryne and aldicarb, respectively. This is the lowest limit of detection achieved so far for luminescent
lanthanide-based probes for pesticides. The interaction of the probe with the pesticides has been investigated using cyclic
voltammetry (CV), differential pulse polarography (DPP), square wave voltammetry (SWV) and linear sweep voltammetry (LSV)
on a glassy carbon electrode in I = 0.1 mol L−1 p-toluenesulfonate at 25 °C. The diffusion coefficients of the reduced species are calculated. The main properties of the
electrode reaction occurring in a finite diffusion space are the quasireversible maximum and the splitting of the net SWV
peak for Eu(III) ions in the ternary complex formed . It was observed that the increase of the cathodic peak currents using
LSV is linear with the increase of pesticides concentration in the range 5 × 10−7 to 1 × 10−5 mol L−1. The detection limit (DL) were about 1.01, 2.23 and 1.89 μmolL−1 for aldicarb, methomyl and prometryne, respectively. In order to assess the analytical applicability of the method, the influence
of various potentially interfering species was examined. Influence of interfering species on the recovery of 10 μmol L−1 pesticides has been investigated. 相似文献
996.
997.
Fomin N Arrington J Asaturyan R Benmokhtar F Boeglin W Bosted P Bruell A Bukhari MH Christy ME Chudakov E Clasie B Connell SH Dalton MM Daniel A Day DB Dutta D Ent R El Fassi L Fenker H Filippone BW Garrow K Gaskell D Hill C Holt RJ Horn T Jones MK Jourdan J Kalantarians N Keppel CE Kiselev D Kotulla M Lindgren R Lung AF Malace S Markowitz P McKee P Meekins DG Mkrtchyan H Navasardyan T Niculescu G Opper AK Perdrisat C Potterveld DH Punjabi V Qian X Reimer PE Roche J Rodriguez VM Rondon O 《Physical review letters》2012,108(9):092502
We present new measurements of electron scattering from high-momentum nucleons in nuclei. These data allow an improved determination of the strength of two-nucleon correlations for several nuclei, including light nuclei where clustering effects can, for the first time, be examined. The data also include the kinematic region where three-nucleon correlations are expected to dominate. 相似文献
998.
999.
Fida El Chami 《印度理论与应用数学杂志》2012,43(1):71-86
In this paper, we give a branching law from the group Sp(n) to the subgroup Sp(q) × Sp(n-q). We propose an application of this result to compute the Laplace spectrum on the forms of the manifold Sp(n)/Sp(q)×Sp(n-q), using the “identification” of the Laplace operator with the Casimir operator in symmetric spaces. 相似文献
1000.
Hamacek J Poggiali D Zebret S El Aroussi B Schneider MW Mastalerz M 《Chemical communications (Cambridge, England)》2012,48(9):1281-1283
A new tripodal ligand has been designed by connecting pyridine-based coordination units to a rigid triptycene moiety. Its reaction with europium(III) provides three-dimensional tetranuclear edifices, whose structural and photophysical characteristics as well as host-guest interactions are discussed in this contribution. 相似文献