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951.
W. Mahmoud A. F. Ghaleb E. K. Rawy H. A. Z. Hassan A. A. Mosharafa 《Archive of Applied Mechanics (Ingenieur Archiv)》2014,84(9-11):1501-1515
A numerical solution is presented for a nonlinear, one-dimensional boundary-value problem of thermoelasticity with variable volume force and heat supply in a half-space. The surface of the body is subjected to a given periodic displacement. The volume force and bulk heating simulate the effect of a beam of particles infiltrating the medium. No phase transition is considered and the domain of the solution excludes any shock wave formation. The basic equations are formulated in material coordinates, making them adequate for dealing with moving boundaries. The used numerical scheme reproduces correctly the process of coupled thermomechanical wave propagation. The presented figures display the process of propagation of the coupled nonlinear thermoelastic waves. They also show the effects of volume force and heat supply on the distributions of the mechanical displacements and temperature inside the medium. Moreover, the interplay between these two factors and the applied boundary disturbance is outlined. The presented solutions, however, is not meant to capture the expected process of shock formation at the breaking distance. 相似文献
952.
M. El-Azab Farid K. O. Behairy Z. M. M. Mahmoud Kasem Omar Hussein 《Brazilian Journal of Physics》2014,44(1):73-90
The elastic and inelastic scattering of 6Li on 12C, 58Ni, 90Zr, and 208Pb targets at 600 MeV are analyzed via double-folding optical model potentials based on the S1Y effective nucleon–nucleon (NN) interaction and tρρ approximation. Information is provided, by single- and coupled-channel calculations, on the effect of breakup and its feedback on the elastic scattering of 6Li ions. Experimental results are successfully reproduced. The in-medium NN cross-section and second-order (double-scattering) correction to the tρρ potential are taken into account. Reaction cross-sections are computed from exact and approximate solutions. 相似文献
953.
Damping in a Squeezed Bath and Its Time Evolution through the Complete Class of Gaussian Quasi-Distributions 下载免费PDF全文
By virtue of the thermo-entangled states representation of the density operator and using the dissipative interaction picture, we solve the master equation of a driven damped harmonic oscillator in a squeezed bath. We show that the essential part of the dynamics can be expressed by the convolution of the initial Wigner function with a special kind of normalized Gaussian in the phase space and relate the dynamics with the change of Gaussian ordering of the density operator. 相似文献
954.
Lorenzo Maschio Raffaella Demichelis Roberto Orlando Marco De La Pierre Agnes Mahmoud Roberto Dovesi 《Journal of Raman spectroscopy : JRS》2014,45(8):710-715
Raman spectroscopy is a standard and powerful investigation technique for minerals, and garnet is one of the most observed and visible minerals, undoubtfully important both as a witness of our planet's evolution and as a main component in many high‐tech applications. This paper presents the Raman spectrum of grossular, the calcium–aluminium end‐member of garnets (Ca 3Al 2Si 3O12), as computed by using an ab initio quantum‐mechanical approach, an all‐electron Gaussian‐type basis set and the hybrid B3LYP functional. The wavenumbers of the 25 Raman active modes are in excellent agreement with the available experimental measurements, with the mean absolute difference being between 5 and 8 cm − 1. The apparent disagreement between a few experimental vs calculated data can be easily justified through the analysis of the corresponding calculated peak intensities, which is very low in all of these cases. The intensities of the Raman active modes of grossular were calculated here for the first time, thanks to a recent implementation by some of the present authors that allow for accurate predictions of the Raman spectra of minerals. To the authors’ knowledge, there are no tabulated data sets for Raman intensities of grossular, although qualitative information can be extracted from the published spectra. This study can then be considered as an accurate reference data set for grossular, other than a clear evidence that quantum‐mechanical simulation is an actual tool to predict spectroscopic properties of minerals. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
955.
Tobias König Rajesh Kodiyath Zachary A. Combs Mahmoud. A. Mahmoud Mostafa A. El‐Sayed Vladimir V. Tsukruk 《Particle & Particle Systems Characterization》2014,31(2):274-283
We report on silver nanocubes (AgNCs) infiltrated into cylindrical nanopores of porous alumina membranes (PAM) with an outstanding chemical sensitivity based on refractive index sensing (RIS) measurements. Numerical simulations performed using the finite‐difference time‐domain (FDTD) method suggested that the enhanced sensitivity is based mainly on the inter‐pore coupling plasmonic effect. This effect is related to plasmonic amplification based on localized surface plasmon resonance (LSPR) coupling between AgNCs located at the pore walls of neighboring cylindrical pores and separated by a nanoscale wall. Results are discussed for different aggregation scenarios ranging from individual nanocubes through pentamers on a flat glass surface, a flat alumina surface, and a concave local shape representing the experimental conditions. An experimental RIS sensitivity of about 770 nm per refractive index unit was found to be more than an order of magnitude higher for silver nanocube aggregates within cylindrical pores than that observed for ordinary planar substrates. 相似文献
956.
Mostafa A. A. Mahmoud 《国际流体数值方法杂志》2011,67(11):1692-1701
The influence of thermal radiation on the flow and heat transfer within Newtonian liquid film over an unsteady stretching sheet with and without thermocapillarity is examined. The governing non‐linear partial differential equations describing the problem are reduced to a system of nonlinear ordinary differential equations using similarity transformation, which is solved numerically for different values of the thermal radiation parameter and the thermocapillarity parameter. The results show that the dimensionless velocity, the film thickness and the local Nusselt number increase as the thermocapillarity parameter increases, while the free surface temperature decreases with increasing the thermocapillarity parameter. Also, both the dimensionless temperature and the free surface temperature increase and the local Nusselt number decreases as the thermal radiation parameter increases. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
957.
Fariman Fathi Mahmoud Tabrizchi Hossein Farrokhpour 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(3):226-231
In this work, the time domain of optogalvanic signal is considered as an extra dimension for the analysis of the optogalvanic spectra. A time window was used to integrate over the different time regions of the temporal OG signals for each wavelength. The method enhanced the resolution of spectra considerably so that two closed transitions, which differ only by 4 pm, were precisely separated. In addition a new transition of Neon around 640 nm masked by a transition at 640.229 nm was observed and assigned using the new method. 相似文献
958.
Mahmoud F. Farhat Mansour A. Makhlouf Ahmed M. El-Saghier Aysha B.A. Mezoughi Salma M. Awhida Amal A.M. El-mehdi 《Arabian Journal of Chemistry》2011,4(3):307-311
2-Ylidene and 2,5-diylidene-4-thiazolidinones 2a–d were synthesized and converted into pyrazole derivatives 4a–d by reaction with hydrazine hydrate. A mechanism of this novel conversion is suggested. 相似文献
959.
Achraf Lahyani Manef Chtourou Mohamed Hédi Frikha Mahmoud Trabelsi 《Ultrasonics sonochemistry》2013,20(5):1296-1301
This paper presents an improved synthesis of trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones under ultrasound irradiation in the presence of commercial acid-resins as catalysts in solvent free conditions. Several trans-chalcones and α,α′-bis(arylmethylidene) cycloalkanones were synthesized in good yields and excellent selectivity in a short reaction time. 相似文献
960.
Synthesis,characterization and anticancer studies of ferrocenyl complexes containing thiazole moiety
Mokhles M. Abd‐Elzaher Samia A. Moustafa Ammar A. Labib Hanan A. Mousa Mamdouh M. Ali Abeer E. Mahmoud 《应用有机金属化学》2012,26(5):230-236
A ferrocenyl ligand was prepared from condensation of l,l′‐diacetylferrocene with 2‐amino‐5‐methylthiazole, to give the ligand. This ligand forms 1:1 complexes with lead(II), cobalt(II), nickel(II), copper(II) and zinc(II) in good yield. Characterization of the ligand and complexes was carried out using IR, NMR, electronic absorption, magnetic susceptibility, molar conductivity and elemental analysis. Anticancer activity of the prepared ligand and its complexes against breast cancer cell line MCF‐7 was determined. The anticancer activity of the new complexes was accompanied by significant increase in the activity of superoxide dismutase, with a parallel decrease in the activities of catalase and glutathione peroxidase and reduced glutathione level. Accordingly, the overproduction of free radicals allowed reactive oxygen species‐mediated cancer cell death. The results suggest that the complexes possess significant anticancer activity comparable to cisplatin. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献