排序方式: 共有122条查询结果,搜索用时 93 毫秒
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Toufik Hadjersi 《Applied Surface Science》2007,253(9):4156-4160
The mechanism of metal-assisted electroless etching of silicon in HF-oxidizing agent-H2O etching system as a function of oxidizing agent concentration was studied. Three types of oxidizing agent were experimented namely Na2S2O8, K2Cr2O7 and KMnO4. Their concentrations were varied from 0.05 M to 0.3 M. The layers formed on silicon were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray (EDX). It is shown that an insoluble solid-phase film (K2SiF6) form on silicon surface when concentration of K2Cr2O7 or KMnO4 increases in chemical solutions. On other hand, when Na2S2O8 concentration increases, the surface roughness decreases without any chemical complex formation. 相似文献
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Johannes Hatzl Toufik Mansour Mark Shattuck 《Journal of Mathematical Modelling and Algorithms》2011,10(2):193-203
Consider the set S of points in the plane consisting of the ordered pairs (i, j ), where
1 \leqslant i \leqslant m1 \leqslant i \leqslant m and
1 \leqslant j \leqslant n1 \leqslant j \leqslant n. A problem related to the study of segmentation evaluation of visual images concerns finding a permutation σ of the points of S for which the sum
?s ? Sd(s, s(s)) \sum\limits_{s \in S}d(s, \sigma(s)) 相似文献
4.
In this paper, the approximate controllability of neutral stochastic fractional differential equations involving nonlocal initial conditions is studied. By using Sadovskii’s fixed point theorem with stochastic analysis theory, we derive a new set of sufficient conditions for the approximate controllability of semilinear fractional stochastic differential equations with nonlocal conditions under the assumption that the corresponding linear system is approximately controllable. Finally, an application to a fractional partial stochastic differential equation with nonlocal initial condition is provided to illustrate the obtained theory. 相似文献
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Experiments on two-dimensional fluidized beds of glass beads are presented for two fluids of typical Reynolds numbers of about 1 and a few hundred. The presence of inertial effects leads to the formation of wakes behind the particles and consequently to an anisotropy of the microstructure. The microstructures, studied by video imaging, are characterized by pair probability distribution functions and structure factors. 相似文献
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Toufik Mansour 《Letters in Mathematical Physics》2009,87(1-2):1-18
A q-analogue of the polylogarithm function is introduced via a consideration of the spectral zeta-function of the quantum group SU q (2). We derive certain identities for linear and non-linear combinations of the q-analogue of polylogarithm functions with negative exponents. 相似文献
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We generalize the kernel method to equation systems in which the number of unknowns is allowed to exceed the number of equations. With this generalization, we derive the generating functions for several kinds of sequences and generating trees whose recursions are dependent on the parity of the indices. 相似文献
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Toufik Kanit Samuel ForestDominique Jeulin Franck N’GuyenScott Singleton 《Mechanics Research Communications》2011,38(2):136-140
Optimal shape design of microstructured materials has recently attracted a great deal of attention in materials science. The shape and the topology of the microstructure have a significant impact on the macroscopic properties. This paper presents different computational models of random microstructures, to virtually improve the physical properties of ice cream. Several sensory properties of this heterogeneous material issued from food industry are directly controlled by the elastic and thermal conducting ones. The material effective elastic and thermal conducting properties are obtained through direct large scale numerical simulations. The different formulations address the problem of finding the shape of the representative microstructural element for random heterogeneous media that increase the elastic moduli and thermal conductivity compared to existing products. The computational models are established using finite element method and images of virtual microstructures. In this paper we propose a new model of microstructures. This model is constructed with hexagonal prismatic rods and plates with volume fractions around 0.7 for the hard phase represented by hexagons of ice. A comparison between three two-phase elastic heterogeneous microstructures models is drawn. This illustrates the concept of design of microstructures using computational homogenization tools. 相似文献
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Toufik Mansour 《Discrete Mathematics》2011,311(16):1778
The chromatic polynomial of a simple graph G with n>0 vertices is a polynomial of degree n, where αk(G) is the number of k-independent partitions of G for all k. The adjoint polynomial of G is defined to be , where is the complement of G. We find explicit formulas for the adjoint polynomials of the bridge–path and bridge–cycle graphs. Consequence, we find the zeros of the adjoint polynomials of several families of graphs. 相似文献
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Let x and y be two variables satisfying the commutation relation xy=qyx+hf(y), where f(y) is a polynomial. In this paper, using Young diagrams and generating functions techniques, we study the binomial formula
(x+y)
n
and we present an identity for x
m
y. The connection to Operator Calculus is discussed and several special cases are treated explicitly. 相似文献
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