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51.
The volatile compounds obtained by hydrodistillation of the aerial parts of Rosmarinus tournefortii De Noé. growing wild in the occidental region of Algeria were analyzed by GC/MS. Thirty-six compounds were characterized representing 95.6% of the essential oil, with camphor (37.6%), 1,8-cineole (10.0%), p-cymene-7-ol (7.8%), and borneol (5.4%) as the major components. The antimicrobial activity was evaluated against three pathogenic bacteria: Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus). The minimum inhibitory concentration (MIC; mg/mL) was determined by sub-culture on Muller Hinton agar plates. The essential oil exhibited strong antibacterial activity against E. coli and P. aeruginosa, and was also active against Staphylococcus aureus. 相似文献
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Akoa François Hachemi Abdelkader Le Thi Hoai An Mouhtamid Said Pham Dinh Tao 《Journal of Global Optimization》2007,37(4):609-630
Direct methods provide elegant and efficient approaches for the prediction of the long-term behaviour of engineering structures
under arbitrary complex loading independent of the number of loading cycles. The lower bound direct method leads to a constrained
non-linear convex problem in conjunction with finite element methods, which necessitates a very large number of optimization
variables and a large amount of computer memory. To solve this large-scale optimization problem, we first reformulate it in
a simpler equivalent convex program with easily exploitable sparsity structure. The interior point with DC regularization
algorithm (IPDCA) using quasi definite matrix techniques is then used for its solution. The numerical results obtained by
this algorithm will be compared with those obtained by general standard code Lancelot. They show the robustness, the efficiency
of IPDCA and in particular its great superiority with respect to Lancelot. 相似文献
55.
Callé S Remenieras JP Matar OB Hachemi ME Patat F 《The Journal of the Acoustical Society of America》2005,118(5):2829-2840
One of the stress sources that can be used in dynamic elastography imaging methods is the acoustic radiation force. However, displacements of the medium induced by this stress field are generally not fully understood in terms of spatial distribution and temporal evolution. A model has been developed based on the elastodynamic Green's function describing the different acoustic waves generated by focused ultrasound. The function is composed of three terms: two far-field terms, which correspond to a purely longitudinal compression wave and a purely transverse shear wave, and a coupling near-field term which has a longitudinal component and a transverse component. For propagation distances in the shear wavelength range, the predominant term is the near field term. The displacement duration corresponds to the propagation duration of the shear wave between the farthest source point and the observation point. This time therefore depends on the source size and the local shear modulus of the tissue. Evolution of the displacement/time curve profile, which is directly linked to spatial and temporal source profiles, is computed at different radial distances, for different durations of force applications and different shear elastic coefficients. Experimental results performed with an optical interferometric method in a homogeneous tissue-mimicking phantom agreed with the theoretical profiles. 相似文献
56.
Allyl alcohols adsorbed on Al2O3-KF at room temperature reacted with trichloroacetonitrile and gave rearranged trichloroacetamides at room temperature, in one pot reaction. 相似文献
57.
This paper presents an efficient modelling of autonomous flexible airships. These flying objects lighter than air (L.T.A.)
are assumed to undergo large rigid-body motion and small elastic deformation. The formalism used is based on the Euler–Lagrange
approach. The airship considered in this study is represented by a flexible ellipsoid of revolution. The coupling between
the added masses issued from the overall body motion and those issued from the elasticity was determined by means of the velocity
potential flow theory. We develop a fully analytical methodology with some assumptions. This feature distinguishes the current
work from earlier treatments of the coupling, it allows one to minimise the number of degrees of freedom of the dynamical
model, and renders the model suitable for use in the algorithms of stabilisation and trajectory generation. Numerical simulations
are presented at the end of this paper. They underline the interest of the developed theoretical results. 相似文献
58.
Oriol Arteaga Carlos Escudero Dr. Gerard Oncins Dr. Zoubir El‐Hachemi Dr. Joan Llorens Dr. Joaquim Crusats Dr. Adolf Canillas Dr. Josep M. Ribó Prof. 《化学:亚洲杂志》2009,4(11):1687-1696
Nanophases of J‐aggregates of several achiral amphiphilic porphyrins, which have thin long acicular shapes (nanoribbons), show the immediate and reversible formation of a stationary mechano‐chiral state in the solution by vortex stirring, as detected by their circular dichroic signals measured by 2‐modulator generallized ellipsometry. The results suggest that when a macroscopic chiral force creates supramolecular chirality, it also creates an enantiomeric excess of screw distortions, which may be detected by their excitonic absorption. An explanation on the effect of the shear flow gradients is proposed on the basis of the orientation of the rotating particles in the vortex and the size, shape, and mechanical properties of the nanoparticles. 相似文献
59.
Ilhem Djellit Mohamed Lamine Sahari Amel Hachemi 《Journal of Applied Analysis & Computation》2013,3(1):11-20
In this work, we consider some dynamical properties and specific contactbifurcations of a discrete-time predator-prey system having inverseswith vanishing denominator. The dynamics is investigated by usingconcepts of focal points, prefocal curves and bifurcation theory.The system undergoes flip bifurcation and Neimark-Sacker bifurcation.Numerical simulations are presented not only to illustrate our resultswith the theoretical analysis, but also to confirm further the complexityof the dynamical behaviors as extinction, persistence and permanence. 相似文献
60.
Il Nuovo Cimento D - We report on calculations of excitonic properties of weakly one-dimensional quantum wires where the exciton centre of mass is quantized by the harmonic potentials of electron... 相似文献