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31.
Let k be an integer (k?1) and G=(V,E) a graph with more than k vertices, a graph G′=(V,E′) is a k-reconstruction of G if, for any subset W of V with k elements, the subgraphs G(W) and G′(W) induced by W are isomorphic. The graph G is k-reconstructible when each k-reconstruction of G is isomorphic to G. Lopez (Z. Math. Logik Grundlag. Math. 24 (1978) 303–317) proved that any graph is 6-reconstructible. For k=3,4 and 5, the k-reconstructible graphs were studied in Boudabbous and Lopez (Eur. J. Combin. 23 (2002) 507–522; C. R. Acad. Sci. Paris, Sér. I 329 (1999) 845–848). In this Note, we introduce a permutations group allowing for the interpretation of the 2-reconstructibility and we characterize the graphs which are embedded in a 2-reconstructible graph. To cite this article: A. Boussairi, A. Chaichaa, C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
32.
Abdelhak Kaci Nadia Ouari Guillaume Racineux Mohend Chaouche 《European Journal of Mechanics - B/Fluids》2011,30(1):129-134
Studying the flow of highly concentrated granular suspensions represents a great challenge since they are characterized by a rather complex rheological behavior. In addition, macroscopic heterogeneities may be induced by the flow during rheological measurements due to the eventual relative motion between the liquid and the granular phases that may take place under certain conditions. Solid–liquid separation may ultimately lead to flow blockage. In the present investigation we consider experimentally the influence of the rheological properties of the suspending fluid on the transition between the flow and blockage of a concentrated suspension in a squeeze set-up geometry. The suspending fluid consists of an aqueous Xanthan solution for which rheological properties can be tuned by changing the polymer concentration. For each polymer concentration, it is shown that there exist flow parameters (squeeze velocity and gap thickness) for which one has a transition between homogeneous flow of the suspension and its blockage. Blockage diagrams, delimiting flowability and blockage zones, are then determined. Physical arguments are given to relate the evolution of the blockage diagrams to the flow parameters and rheological properties of suspending fluid. 相似文献
33.
Abdelhak Fahsi Mohamed Belhaq 《Communications in Nonlinear Science & Numerical Simulation》2009,14(1):244-253
We study the effect of high-frequency harmonic excitation on the entrainment area of the main resonance in a van der Pol–Mathieu–Duffing oscillator. An averaging technique is used to derive a self- and parametrically driven equation governing the slow dynamic of the oscillator. The multiple scales method is then performed on the slow dynamic near the main resonance to obtain a reduced autonomous slow flow equations governing the modulation of amplitude and phase of the slow dynamic. These equations are used to determine the steady state response, bifurcation and frequency–response curves. A second multiple scales expansion is used for each of the dependent variables of the slow flow to obtain slow slow flow modulation equations. Analysis of non-trivial equilibrium of this slow slow flow provides approximation of the slow flow limit cycle corresponding to quasi-periodic motion of the slow dynamic of the original system. Results show that fast harmonic excitation can change the nonlinear characteristic spring behavior and affect significantly the entrainment region. Numerical simulations are used to confirm the analytical results. 相似文献
34.
Abdelhak Abouqateb 《manuscripta mathematica》1999,98(3):349-362
The purpose of this paper is to characterise the invariant sections-distributions by a proper action. More precisely, we show
that if G is a connected Lie group acting on a differentiable vector bundle E→V such that the induced action on V is proper, then the topological vector space of the G-invariant linear functionals (on the space of C
∞ sections with compact support) equipped with the induced weak-topology (resp. the strong-topology), is isomorphic to the
weak (resp. strong) topological dual of the space (of all G-invariant sections σ with compact quotient supp(σ)/G) equipped with a suitable topology; this coincides with the
usual C
∞-topology if the orbit space is compact, and with the Schwartz-topology if the group G is compact.
Received: 8 June 1998 / Revised version: 22 September 1998 相似文献
35.
Effect of pressure and space between electrodes on the deposition of SiN_xH_y films in a capacitively coupled plasma reactor
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The fluid model, also called the macroscopic model, is commonly used to simulate low temperature and low pressure radiofrequency plasma discharges. By varying the parameters of the model, numerical simulation allows us to study several cases, providing us the physico-chemical information that is often difficult to obtain experimentally. In this work, using the fluid model, we employ numerical simulation to show the effect of pressure and space between the reactor electrodes on the fundamental properties of silicon plasma diluted with ammonia and hydrogen. The results show the evolution of the fundamental characteristics of the plasma discharge as a function of the variation of the pressure and the distance between the electrodes. By examining the pressure-distance product in a range between 0.3 Torr 2.7 cm and 0.7 Torr 4 cm, we have determined the optimal pressure-distance product that allows better deposition of hydrogenated silicon nitride(Si N_x H_y)films which is 0.7 Torr 2.7 cm. 相似文献
36.
El Gaidoumi Abdelali Doña-Rodríguez José Miguel Pulido Melián Elisenda González-Díaz Oscar Manuel El Bali Brahim Navío José Antonio Kherbeche Abdelhak 《Research on Chemical Intermediates》2019,45(2):333-353
Research on Chemical Intermediates - Pyrophyllite–TiO2 nanocomposite PTi750 was successfully synthesized using a sol–gel method at ambient temperature based on exfoliation of the... 相似文献
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38.
The European Physical Journal C - Now that the Higgs particle has been observed by the ATLAS and CMS experiments at the LHC, the next endeavor would be to probe its fundamental properties and to... 相似文献
39.
Abdelhak Belaidi Thomas Dittrich David Kieven Julian Tornow Klaus Schwarzburg Martha Lux‐Steiner 《固体物理学:研究快报》2008,2(4):172-174
The local absorber layer thickness (dlocal) of solar cells with extremely thin absorber was changed between 10 nm and 70 nm. As a model system, ZnO nanorod arrays (electron conductor) with fixed internal surface area coated with In2S3 (absorber) and impregnated with CuSCN (transparent hole conductor) were applied. The performance of the small area solar cells depended critically on dlocal. The highest short circuit current density was reached for the lowest dlocal. In contrast, the highest open circuit voltage was obtained for the highest dlocal. A maximum energy conversion efficiency of 3.4% at AM1.5 was achieved. Limiting factors are discussed.(© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
40.
Abdelhak Djouadi 《Pramana》2004,62(2):191-206
I review the physics of the Higgs sector in the standard model and its minimal supersymmetric extension, the MSSM. I will
discuss the prospects for discovering the Higgs particles at the upgraded Tevatron, at the large hadron collider, and at a
future high-energye
+
e
− linear collider with centre-of-mass energy in the 350–800 GeV range, as well as the possibilities for studying their fundamental
properties. Some emphasis will be put on the theoretical developments which occurred in the last two years. 相似文献