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We have investigated the interaction of obliquely propagating ion acoustic solitary waves in a magnetoplasma with relativistically degenerate electrons. Using the quantum hydrodynamics model and by employing the extended Poincaré–Lighthill–Kuo technique, we have derived a set of Korteweg de Vries equations for two solitons. We have observed that the system under consideration allows the formation of only compressive solitons and their velocities remain in the sub-acoustic limit. Furthermore, phase shifts of solitons as a result of their interaction have been calculated. The phase shifts have been observed to be dependent on the obliqueness and the physical parameters of plasma. It has also been noticed that phase shifts remain negative for the whole range of parameters generally found in white dwarf stars. We have observed that the phase shifts enhance with the enhancement in number density, however, the converse happens when the magnetic field is enhanced. It has also been observed that the phase shift is slightly greater for the solitons that are less oblique as compared to their more oblique counterparts. Furthermore, we have estimated the spatial scales of interaction of solitons using the parameters found in white dwarf stars. 相似文献
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Exact analytical solutions for a class of unsteady unidirectional flows of an incompressible second-order fluid are constructed. The flows are generated impulsively from rest by motion of a plate or two plates or by sudden application of a pressure gradient. Expressions for velocity, flux and skin friction are obtained for both large and small times. It is found that large and small times solutions are dependent on the coefficient of viscoelasticity. The solutions corresponding to Newtonian fluids can be easily obtained from those for fluids of second order by letting the viscoelastic parameter to be zero. 相似文献
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Ali Haider Zareen Akhter Humaira Masood Siddiqi Edward R. T. Tiekink 《Journal of chemical crystallography》2010,40(5):397-401
Abstract
The molecule of 4-aminobenzohydrazide is essentially planar and geometric parameters conform to literature precedents. Supramolecular N–H···O and N–H···N interactions combine to link molecules of 4-aminobenzohydrazide into a three-dimensional network. Weaker N–H···N and N–H···π interactions consolidate the structure. The compound crystallizes in the monoclinic space group P21/n with a = 5.411(2) ?, b = 14.000(6) ?, c = 9.894(4) ?, β = 103.917(7)o, and Z = 4. 相似文献28.
Efficient visible-light-induced photocatalytic degradation of MO on the Cr-nanocrystalline titania-S
Masood Hamadanian Ali Sadeghi SarabiAli Mihammadi Mehra Vahid Jabbari 《Applied Surface Science》2011,257(24):10639-10644
In order to improve visible light photocatalytic activities of the nanometer TiO2, a novel and efficient Cr,S-codoped TiO2 (Cr-TiO2-S) photocatalyst was prepared by precipitation-doping method. The crystalline structure, morphology, particle size, and chemical structure of Cr-TiO2-S were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Fourier transform infrared (FT-IR) techniques, respectively. Results indicate that the doping of Cr and S, cause absorption edge shifts to the visible light region (λ > 420 nm) compare to the pure TiO2, reduces average size of the TiO2 crystallites, enhances desired lattice distortion of Ti, promotes separation of photo-induced electron and hole pair, and thus improves pollutant decomposition under visible light irradiation. The photocatalytic activities of Cr-TiO2-S nanoparticles were evaluated using the photodegradation of methyl orange (MO) as probe reaction under the irradiation of UV and visible light and it was observed that the Cr-TiO2-S photocatalyst shows higher visible photocatalytic activity than the pure TiO2. The optimal Cr-TiO2-S concentration to obtain the highest photocatalytic activity was 5 mol% for both of Cr and S. 相似文献
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In this paper we discuss the integrability of the generalized Lane–Emden equations of the first and second kinds. We carry
out their Noether symmetry classification. Various cases for the arbitrary functions in the equations are obtained for which
the equations have Noether point symmetries. First integrals of such cases are obtained and also reduction to quadrature of
the corresponding Lane–Emden equations are presented. New cases are found. 相似文献
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A mathematical two-phase model is used to numerically investigate physical and rheological effects on small, individual bubbles in high-viscosity liquids under pressure impact. It is found out that bubbles remain stable over time at high viscosity and surface tension. The steady case is considered and connected to the stability behavior of the bubble. An upper bound for the bubble radius is derived and the new equilibrium state of the bubble can be predicted by means of stability theorems of differential equations. Finally, the interaction of a limited number of well separated bubbles in an Hele-Shaw flow is mathematically analyzed to visualize and physically interpret their trajectories. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献