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11.
Hamid Ait Abderrahmane Kamran Siddiqui Georgios H. Vatistas 《Experiments in fluids》2011,50(3):677-688
The rotating waves within a hollow vortex core (polygonal patterns) are generated under shallow water conditions inside a
cylindrical tank by a revolving disk at its bottom. We previously reported some basic features of these polygonal patterns
during transition and at the equilibrium states. The present paper includes a more comprehensive investigation into the transition
process of these polygonal patterns and expands the recent partial results that have been previously reported. We show that
the parent wave (or the N-gon pattern) to disk frequencies ratio is around one-third (1/3) regardless of the flow conditions. A detailed insight into the transition process from the parent wave N-gon to daughter wave (N + 1)-gon is provided, which consists of two regimes, quasi-periodic and synchronized. Based on these observations, we explained the
shrinking of the disk speed subintervals over which the N-gon patterns occur, when N increases. 相似文献
12.
Reine-Marie Dia Rim Belaqziz Abderrahmane Romane Elisabet Duñach 《Tetrahedron letters》2010,51(16):2164-5160
A chemoenzymatic access to thiol compounds, including ethyl 3-thiobutanoate, 3-thio-p-menthene and 8-thio-p-menthan-2-one, three compounds of interest in flavour and fragrance chemistry presenting various fruity notes, is proposed. It involves an indium(III)-catalysed hydrothioacetylation of renewable precursors followed by an enzymatic solvolysis of the obtained thioesters by lipases in aqueous or organic solvents. 相似文献
13.
A conjecture of P. Erdös says that the diophantine equationx+y = z has infinitely many solutions with (x,y) = 1 and suchthat if a prime p divides xyz, then p3 divides xyz. In thispaper, we give a proof of this conjecture. 相似文献
14.
Abderrahmane Nitaj Willy Susilo Joseph Tonien 《Journal of Applied Mathematics and Computing》2017,55(1-2):293-312
Boolean functions play an important role in many symmetric cryptosystems and are crucial for their security. It is important to design boolean functions with reliable cryptographic properties such as balancedness and nonlinearity. Most of these properties are based on specific structures such as Möbius transform and Algebraic Normal Form. In this paper, we introduce the notion of Dirichlet product and use it to study the arithmetical properties of boolean functions. We show that, with the Dirichlet product, the set of boolean functions is an Abelian monoid with interesting algebraic structure. In addition, we apply the Dirichlet product to the sub-family of coincident functions and exhibit many properties satisfied by such functions. 相似文献
15.
The main propose of this paper is to study the blow-up of solutions of an initial boundary value problem with a nonlocal boundary condition for a system of nonlinear singular viscoelastic equations. where the blow-up of solutions in finite time with nonpositive initial energy combined with a positive initial energy are shown. 相似文献
16.
Bouzidi Abdelkader Imessaoudene Djillali Ararem Abderrahmane Aissaoui Regadia 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(1):409-418
Four types of undisturbed soils around the Es-Salam reactor (Algeria) were used to evaluate the sorption behavior of strontium. The batch study was carried out under different experimental conditions. The kinetics were well fited by pseudosecond order model. Soils’s activation energies were 12.37, 14.76, 15.5 and 16.17 kJ mol−1, corresponding to ion-exchange-type sorption. Sorption was exothermic (ΔH° < 0), spontaneous (ΔG° < 0) and favorable at low temperature. Competing cations, particularly Ca2+ reduce the Sr adsorption. Desorption reaction showed a higher value of Sr in the easily extractible phase indicating a relative availability of the element.
相似文献17.
Asma Ben Ghnaya Ismail Amri Haifa Ahoues Mohsen Hanana Abderrahmane Romane 《Natural product research》2016,30(18):2058-2064
Allelopathic materials inside a tree can produce positive or negative change in the survival, growth, reproduction and behaviour of other organisms if they escape into the environment. To assess these effects, this work was carried out to evaluate the allelopathic impact of Eucalyptus erythrocorys L. on seed germination and seedling growth of two weeds: Sinapis arvensis L. and Phalaris canariensis L.; on one cultivated crop: Triticum durum L. Aqueous; and on ethanolic leaf extracts of E. erythrocorys L. The study was effected using four concentrations (10, 20, 25 and 30 μL/mL) while distilled water was used as a control. The results showed that the E. erythrocorys L. crude extracts had an inhibitory effect on seed germination and seedling growth of both studied weeds and wheat. The inhibition rate was increased by the increase in extract concentration. Only ethanolic extracts of E. erythrocorys L. induced a significant inhibition of seed germination of durum wheat. The effect of E. erythrocorys L. crude extracts was more severe on weeds than on durum wheat. These results indicate that the seedling growth, especially radicle elongation, was the more sensitive indicator to evaluate the effects of extracts than was the seed germination. 相似文献
18.
We introduce a mathematical model based on a concept of intrinsic mode in order to analyse and synthesise optical wave propagation and radiation occurring in a non-uniform optical waveguide used in integrated optics as optical coupler. The model is based on numerical evaluation of electromagnetic wave by applying an intrinsic field integral to evaluate the field behaviour inside the optical waveguide. To analyse the field distribution inside the non-uniform waveguide and predict the beam propagation of optical energy involved in the propagation process, it is necessary to track the motion of any observation point along the tapered waveguide itself. Physically, the rays of the spectrum undergo reflections on the waveguide boundaries until the cut-off occurs and the phenomena of radiation begin. The numerical results show good agreement with those obtained by classical methods of evaluation used bv other works. 相似文献
19.
Amgoune A Ladeira S Miqueu K Bourissou D 《Journal of the American Chemical Society》2012,134(15):6560-6563
The paucity of boron-containing heteroalkene complexes prompted us to explore the coordination of phosphinoboranes. The complexes {[R(2)PB(C(6)F(5))(2)]Pt(PPh(3))(2)} (R = Cy, t-Bu) were obtained by ethylene displacement. Spectroscopic and crystallographic data indicated symmetric side-on coordination of the phosphinoborane to Pt. Thorough analysis of the bonding situation by computational means revealed important similarities but also significant differences between the phosphinoborane and ethylene complexes. 相似文献
20.
We consider a simple but representative model incorporating the main behavior of the electromagnetic field near the edge of a patch antenna. Recall that this kind of antenna is obtained by a metal patch laying on a dielectric substrate covering a ground metallic plane. The functioning principle of such an electric device is based on the matching of an N-dimensional behavior of the field outside the antenna with an (N-1)-dimensional one inside the zone limited by the patch and the ground plane, N = 3 or 2 according to the considered model. In this study, we make use of the technique of matched asymptotic expansions and computation of singularities to describe this behavior for the two-dimensional case. Proved error estimates enable us to give a rigorous background to the underlying asymptotic analysis. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献