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31.
One-dimensional analysis of electron acceleration by a nonlinear chirped Gaussian laser pulse was investigated numerically. Two main nonlinear chirped pulses, polynomial and periodical were used. The maximum energy of electron in nonlinear chirped is approximately three times more than that of linear chirped. In the case of first order nonlinear polynomial chirp, Ω(ξ) = 1 + aξ + bξ 2, the electron can be accelerated up to 5.3 GeV. Indeed, the analysis of the electron trajectory in x-z plane showed that the electron in the field of the nonlinear chirped pulse has a much smaller divergence than that of linear chirped pulse. 相似文献
32.
Hassan Karami Mohammad Ramandi-Ghamooshi Saeedeh Moeini Fatemeh Salehi 《Journal of Cluster Science》2010,21(1):21-34
MnO2 nanoclusters were synthesized by a low temperature hydrothermal method. In the presented procedure, MnO2 was precipitated by oxidation of manganese sulfate solution upon addition of ammonium persulfate solution. The synthesized
sample was characterized by SEM and XRD. Optimized nanoclusters with needle diameters of 30 nm were synthesized by mixing
of manganese sulfate solution (0.8 M) with ammonium persulfate solution (0.7 M) in sulfuric acid media (0.8 M) at constant
temperature of 80 °C. Effect of solid state lithium sulfate treatment on the phase composition, particle size and morphology
of the obtained MnO2 nanoclusters was studied at different temperatures. The obtained results showed that lithium salt can changes MnO2 nanoclusters morphology without any intercalation. Discharge capacity and cycle life of the synthesized MnO2 nanoclusters as positive materials of RAM battery (Zn–MnO2 battery), before and after treatment with lithium sulfate were studied. MnO2 nanopowder showed average discharge capacity of 190 mA.h/g (with respect to MnO2 weight) during 3 first discharges. Lithium sulfate-treated powder showed higher discharge capacity (160 mA.h/g) and shorter
cycle life than the untreated powder. 相似文献
33.
The hybridizations of a graphene layer by a thymine and a uracil nucleobase have been investigated by performing density functional theory (DFT) calculations. The isolated and hybrid structures have been firstly stabilized to reach the minimum energy and the electronic properties have been subsequently evaluated for the optimized structures. The structural and atomic scale parameters indicated that the tip of graphene is important in determining the properties of new hybrids. Moreover, different effects of thymine and uracil nucleobases have been identified in the hybrid structures. Quadrupole coupling constants have been evaluated to characterize the atomic scale properties, in which the most notable effects of hybridizations have been observed for the atoms close to the linking regions whereas negligible effects have been seen for other atoms. 相似文献
34.
Ali Ahmadi Peyghan Mohammad T. Baei Saeedeh Hashemian 《Journal of Cluster Science》2013,24(1):341-347
Adsorption of hydrogen sulfide (H2S) on the external and internal surface of Zn12O12 nanocluster was studied by using density functional calculations. The results indicate that the H2S molecule is physically adsorbed or chemically dissociated by the nanocluster. It was found that the H2S molecule can dissociate into –H and–SH fragments, suggesting that the nanocluster might be a potential catalyst for dissociation of the H2S molecule. Also, dissociation of H2S to S species in internal surface of the Zn12O12 nanocluster is energetically impossible. The HOMO–LUMO energy gap of H2S dissociation configuration is changed about 27.68 %, indicating that the electronic properties of the nanocluster by dissociation process have strongly changed. 相似文献
35.
Saeedeh Sepehrikia Donya Arefi Alireza Shams 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2014,88(13):2462-2465
Fluorescence quantum yield of two novel compounds—dibenzo[c,k]-1,2-dithia-6,9-diazacyclododecane-5,10-dione (1) and dibenzo[c,k]-1,2-dithia-6,9-diaza-7-methylcyclododecane-5,10-dione (2) was studied by Williams method using anthracene as a reference. 相似文献
36.
Ali Ahmadi Peyghan Mohammad T. Baei Parviz Torabi Saeedeh Hashemian 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1172-1177
Abstract Thiophene adsorption on pristine (6,0) aluminum nitride nanotubes was studied by using density functional theory calculations, by means of B3LYP and M06-L functionals. We present the nature of the thiophene interaction in different sites of the nanotube. Adsorption energies corresponding to adsorption of thiophene are calculated to be in the range ?18.90 to ?21.06 kJ mol? 1 . It has been shown that the thiophene molecule has a weak physical adsorption on the pristine models due to weak Van der Waals interaction between the nanotubes and thiophene molecule. The charge transfer between thiophene and the AlNNT is minimal and the electronic properties of the nanotubes are not affected by the thiophene adsorption. Also, with change of tube type, more efficient binding could not be achieved. The results indicate that transition metal nanoclusters are more suitable catalyst with respect to nontransition metal nanotubes in the petroleum industry. 相似文献
37.
Negin S Daschbach MM Kulikov OV Rath N Gokel GW 《Journal of the American Chemical Society》2011,133(10):3234-3237
Pyrogallolarenes are tetrameric macrocycles that form from 1,2,3-trihydroxybenzene and aldehydes under acidic conditions. When 2-ethylbutanal or 2-propylpentanal was so treated, the branched-chain pyrogallolarenes crystallized as nanotubes or bilayers, respectively. When the behavior of each compound was assessed by using the planar bilayer conductance method, pore formation was observed. The properties of the pores were significantly different from each other, probably reflecting different types of pore organization within the membrane. 相似文献
38.
39.
The governing equations for a free dynamic response of a symmetrically laminated composite shell are used to analyze a nonlinear
differential panel. The FEM and the Lindstedt–Poincare perturbation technique are invoked to construct a uniform asymptotic
expansion of the solution to a nonlinear differential equation ofmotion. A comparison between numerical and finite-element
methods for analyzing a symmetrically laminated graphite/epoxy shell panel is performed to show that the nonlinearities are
of hardening type and are more repeated for smaller opening angles. It is also shown that large-amplitude motions are dominated
by lower modes. 相似文献
40.
Saeedeh Tashakor Mohammad R. Noorbala Mansoor Namazian 《International journal of quantum chemistry》2016,116(20):1477-1485
A computational study on the intermolecular potential energy of 44 different orientations of F2 dimers is presented. Basis set superposition error (BSSE) corrected potential energy surface is calculated using the supermolecular approach at CCSD(T) and QCISD(T) levels of theory. The interaction energies obtained using the aug‐cc‐pVDZ and aug‐cc‐pVTZ basis sets are extrapolated to the complete basis set limit using the latest extrapolation scheme. The basis set effect is checked and it is found that the extrapolated intermolecular energies provide the best compromise between the accuracy and computational cost. Among 1320 energy points of F2–F2 system covering more relative orientations, the most stable structure of the dimers was obtained with a well depth of ?146.62 cm?1 that related to cross configuration, and the most unstable structure is related to linear orientation with a well depth of ?52.63 cm?1. The calculated second virial coefficients are in good agreement with experimental data. The latest extrapolation scheme of the complete basis set limit at the CCSD(T) level of theory is used to determine the intermolecular potential energy surface of the F2 dimer. Comparing the results obtained by the latest scheme with those by older schemes show that the new approach provides the best compromise between accuracy and computational cost. 相似文献