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21.
F. Abdous R. Ghaderi A. Ranjbar S. H. Hosseinnia H. Soltani J. Ghasemi 《Journal of Applied Mathematics and Computing》2009,31(1-2):151-163
The main goal of this study is to present a technique to find a state response of multivariable time varying systems. In this paper a novel Homotopy Perturbation based Method (HPM) will be presented to find a dynamic response of time varying system. According to this method, the linear part of the described system is partitioned into two time varying and invariant subsections. Time invariant part analytically constructs the state transition matrix. This matrix is a core of the rest of time varying differential equation without any further changes in a sequence order. The main advantage of this method is only the necessity to solve the time invariant part of the state transition matrix. Simulation results verify the significance of the proposed analytic and asymptotic method. 相似文献
22.
We investigate the decay property of a Timoshenko system of thermoelasticity in the whole space for both Fourier and Cattaneo laws of heat conduction. We point out that although the paradox of infinite propagation speed inherent in the Fourier law is removed by changing to the Cattaneo law, the latter always leads to a solution with the decay property of the regularity‐loss type. The main tool used to prove our results is the energy method in the Fourier space together with some integral estimates. We derive L2 decay estimates of solutions and observe that for the Fourier law the decay structure of solutions is of the regularity‐loss type if the wave speeds of the first and the second equations in the system are different. For the Cattaneo law, decay property of the regularity‐loss type occurs no matter what the wave speeds are. In addition, by restricting the initial data to with a suitably large s and γ ∈ [0,1], we can derive faster decay estimates with the decay rate improvement by a factor of t?γ/2. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
23.
24.
This work, we report a cost effective method to decompose ITO thin layer on polycarbonate as flexible substrate by means of
spin coating technique. Three calcinations techniques were carried out. The coating were deposited by spin and cured by heat,
ultraviolet (UV) irradiation and Nd-YAG pulse laser. The resistivity change on annealing of the amorphous film by thermal,
UV and laser was investigated by X-ray diffraction, scanning electron microscopy, atomic force spectroscopy and UV–Vis spectrometer.
It is shown that the resistance of coated film on polymer decreases dramatically to less than impedance spectroscopy (600 Ω)
when using combination of low heat treatment and laser irradiation with a wavelength of 1,100 nm and energy of 6–25 J. 相似文献
25.
Belkacem Belaabed Jean Luc Wojkiewicz Saad Lamouri Noureddine El Kamchi Nathalie Redon 《先进技术聚合物》2012,23(8):1194-1201
Composites based on conductive organic/inorganic fillers dispersed in insulating matrix have been widely investigated because of their widespread applications such as electromagnetic shielding, electrostatic discharge, and sensors. In this context, novel composite materials based on epoxy resin matrix charged with polyaniline (PANI)‐doped para‐toluene sulfonic acid were elaborated. Fourier transform infrared spectroscopy, X‐ray diffraction and scanning electron microscopy were used to check the structure and the morphology of the samples. Viscoelastic behavior and thermal stability of the composites were explored by dynamic mechanical thermal analysis and thermogravimetric analysis. It was shown that the PANI particles exhibited a partial crystalline structure and were homogeneously dispersed in epoxy matrix. Consequently, this structure affected the thermal stability and viscoelastic properties of the composites. Furthermore, the dielectric and electrical properties were investigated up to 1 MHz. Measurements of dielectric properties revealed that with loading fillers in matrix, the dielectric parameters increased to high values at low frequency then decreased at values around 40 and 32 of real and imaginary parts, respectively, at 1 MHz with 15% of PANI content. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
26.
Belkacem Benmerad Achoura Guehria‐Laïdoudi Grald Bernardinelli Fadila Balegroune 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(3):321-323
The title compound, [La2(C3H2O4)3(H2O)4]·H2O, forms a layer‐type polymeric structure. The layers, which contain infinite puckered four‐membered La—O—La—O rings in a pseudo‐ternary symmetry, are formed by the lanthanum and one independent malonate group. They are interconnected by the second independent malonate group, giving a three‐dimensional framework in which wide channels accommodate one disordered water molecule of crystallization. The La atom lies on a twofold axis and is ten‐coordinated by eight O atoms from carboxylate groups and two water molecules. One malonate group is monodentate and triply bridging chelating, whilst the other is doubly monodentate. The extensive network of hydrogen bonds and bridge bonds observed in this structure enhances the structural stability. Despite some identical subfeatures, this structure is quite different from that observed in [La2(C3H2O4)3(H2O)3]·2H2O. 相似文献
27.
Nouri Parouch Ahmad Koukabi Nadiya Abdous Elham 《Research on Chemical Intermediates》2020,46(7):3295-3310
Research on Chemical Intermediates - In the present study, a magnetically separable potent solid acid nanocatalyst with a facile preparation technique was fabricated via incorporation of fibroin as... 相似文献
28.
Belkacem Bendiffalah 《Comptes Rendus Mathematique》2004,339(6):387-390
We construct a long exact sequence where the extensions modules of a triangular algebra are involved with extension modules of its diagonal algebras. This holds in two cases: either its bimodule is right-projective or it is left-flat. This completes a result of Palmér and Roos about the global dimension of triangular algebras. To cite this article: B. Bendiffalah, C. R. Acad. Sci. Paris, Ser. I 339 (2004). 相似文献
29.
Naziha Ladjal Belkacem Zidelkheir Smail Terchi 《Journal of Thermal Analysis and Calorimetry》2018,133(2):881-891
The thermal degradation of thermally cured vinyl ester resin systems is studied for different heating rates. The kinetic triplets, the activation energy, pre-exponential factor and the reaction model f(α) for the different reaction extent of conversions (α) are estimated using advanced isoconversional methods. Although the thermal degradation curves show the degradation occurs as a single stage, the kinetic parameters suggest the otherwise. The activation energy remains constant for α?=?0.3–0.575 but varies during the initial and final stages of conversion. Similarly, the pre-exponential factor shows considerable variation between the lower and higher reaction extent (α) values. This shows the complexity in the reaction. The probable reaction mechanism that the degradation follows has been explained. The complexity of the thermal degradation and the changes in reaction model f(α) over different reaction extent has been related. The appropriate working temperature for different thermal lifetime of the cured vinyl ester resin system for the failure of conversion α?=?0.2 has been predicted under the nitrogen atmosphere. 相似文献
30.
In this paper, we consider a Timoshenko system with a delay term in the feedback and prove a stability result. The beam is clamped at the endpoints and has, in addition to an internal damping, a feedback with a delay.Under an appropriate assumption on the weights of the two feedbacks, we prove the well-posedness of the system and establish an exponential decay result for the case of equal-speed wave propagation. 相似文献