检索结果-南通市图书馆

Journal of Applied Mathematics and Physics 2019年第11期7卷 2818-2835页

作者： A.Adomou Jonas Edou Siaka Massou Department of Theoretical Physics and Mathematics University of Abomey-CalaviAbomey-CalaviBenin National Superior Institute of Industrial Technology INSTI-LokossaNational University of SciencesTechnologyEngineering and Mathematics of AbomeyAbomeyBenin

The present research work is considered as part II of the previous work entitled [Plane Symmetric Solutions to the Nonlinear Spinor Field Equations in General Relativity Theory, jmp, 2019, 10, 1222-1234]. Here, we opt for the static spherical symmetric metric. In this metric, we have obtained spherical symmetric soliton-like solutions to the spinor field equations with nonlinear terms, which are arbitrary functions of , taking into account the proper gravitational field of elementary particles. Equations with power and polynomial nonlinearities are investigated in detail. It is shown that the initial set of the Einstein and spinor field equations with a power-law nonlinearity possess regular solutions with a localized energy density of the spinor field only if we consider massless particle without losing the generality (m = 0). In this case, a soliton-like configuration has negative energy. In order to define the role of the nonlinearity and the own gravitational field of the elementary particles in this model, we have obtained exact static symmetric solutions to the above spinor field equations in the linear case by considering Dirac’s equations and in flat space-time. It is proved that soliton-like solutions are absent in the linear case. But in flat space-time soliton-like configurations exist and have positive total energy.

关键词： Lagrangian Spherical Symmetric Metric soliton-like Solution

Nonlinear Spinor Field Equations in Gravitational Theory: Spherical Symmetric soliton-like Solutions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Physics 2012年第9期3卷 935-942页

作者： V. Adanhounme A. Adomou F. P. Codo M. N. Hounkonnou University of Abomey-Calavi Mathematical Physics and Applications (ICMPA-UNESCO) Cotonou Republic of Benin

This paper deals with an extension of a previous work [Gravitation & Cosmology, Vol. 4, 1998, pp 107-113] to exact spherical symmetric solutions to the spinor field equations with nonlinear terms which are arbitrary functions of S=ψψ, taking into account their own gravitational field. Equations with power and polynomial nonlinearities are studied in detail. It is shown that the initial set of the Einstein and spinor field equations with a power nonlinearity has regular solutions with spinor field localized energy and charge densities. The total energy and charge are finite. Besides, exact solutions, including soliton-like solutions, to the spinor field equations are also obtained in flat space-time.

关键词： Lagrangian Static Spherical Symmetric Metric Field Equations Einstein Equations Dirac Equation Energy-Momentum Tensor Charge Density Current Vector soliton-like Solution

Revisiting coherent structures in low-speed turbulent boundary layers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2019年第2期40卷 261-272页

作者： Xianyang JIANG State Key Laboratory for Turbulence and Complex Systems Peking University Department of Aeronautics and Astronautics College of EngineeringPeking University

Coherent structures are essential for the momentum exchange and turbulence production in wall-bounded turbulent flows. Diversified coherent structures have been observed in turbulent boundary layers, and hairpin-based vortices dominate most of the relevant literature. However, there is no consensus yet on the origin and forming mechanism of hairpin vortices. Herein, five cornerstones pertaining to the framework of hairpin-based coherent structures are reviewed, and three different hairpin generation mechanisms are clarified. Next, the time-resolved tomographic particle image velocimetry(Tomo-PIV) is used in an early turbulent boundary layer(Re_θ= 420) to investigate the origin of hairpin vortices. The timelines reveal a triangular bulge in the low-speed streak(LSS), and the initial roll-up occurs at two sides of it. Meanwhile, the material surfaces manifest as a three-dimensional(3D) wave structure in the LSS, which may support the model of a soliton-like coherent structure(SCS). Subsequently, the method of Lagrangian-averaged vorticity deviation is used to detect early vortices. We find that the 3D wave structure is flanked by two vortices, thus confirming the roll-up of timelines and demonstrating the advantage of the Lagrangian criteria in capturing structures in complex flows. These results suggest that various coherent structures may evolve from the metamorphosis of 3D wave structures and their later interaction. Finally, the limitations of traditional experimental and post-processing tools are discussed.

关键词： coherent structure hairpin vortex soliton-like coherent structure(SCS)

Plane Symmetric Solutions to the Nonlinear Spinor Field Equations in General Relativity Theory

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Physics 2019年第10期10卷 1222-1234页

作者： A. Adomou Jonas Edou Siaka Massou Department of Theoretical Physics and Mathematics University of Abomey-Calavi Abomey-Calavi Benin National Superior Institute of Industrial Technology INSTI-Lokossa National University of Sciences Technology Engineer-ing and Mathematics of Abomey Abomey Benin

We have obtained exact static plane-symmetric solutions to the spinor field equations with nonlinear terms which are arbitrary functions of invariant , taking into account their own gravitational field. It is shown that the initial set of the Einstein and spinor field equations with a power-law nonlinearity have regular solutions with a localized energy density of the spinor field only if m=0 (m is the mass parameter in the spinor field equations). Equations with power and polynomial nonlinearities are studied in detail. In this case, a soliton-like configuration has negative energy. We have also obtained exact static plane-symmetric solutions to the above spinor field equations in flat space-time. It is proved that in this case soliton-like solutions are absent.

关键词： Lagrangian Static Plane-Symmetric Metric Field Equations Energy-Momentum Tensor Charge Density Current Vector soliton-like Solution

Regularities of Nanofocusing of the Electromagnetic Field of a Fractal Rough Surface

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electromagnetic Analysis and Applications 2019年第8期11卷 117-133页

作者： Nikolay N. Grinchik Galina M. Zayats Olga V. Boiprav Kirill V. Dobrego Volha A. Prykhodzka A.V. Luikov Heat and Mass Transfer Institute of the National Academy of Sciences of Belarus Minsk Belarus Institute of Mathematics of the National Academy of Sciences of Belarus Minsk Belarus Belarusian State University of Informatics and Radioelectronics Minsk Belarus Belarusian National Technical University Minsk Belarus Belarusian State University Minsk Belarus

A consistent physical and mathematical model of the propagation of electromagnetic waves in an inhomogeneous medium with strong discontinuities of the electromagnetic field at the interface of two media, which is a rough surface, was developed. Mathematical modeling of rough surfaces and their profiles was carried out using fractal geometry, which allows us to display the topology of the object as close as possible to reality. For real heterogeneous rough structures, we have developed a through-counting method that takes into account the continuity of the total current at the interfaces of adjacent media, the effect of induced surface charge and surface current. This approach lets one avoid the necessity to set surface impedances depending on the structure of the field being determined and on the material properties.

关键词： Nonstationary Broadening of the Spectral Line Fractal Roughness Surface Charge Surface Current Electromagnetic Wave soliton-like Electromagnetic Pulse

Non-Monochromatic Electromagnetic Radiation of Inhomogeneous Media

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Electromagnetic Analysis and Applications 2018年第2期10卷 13-33页

作者： Nicolay N. Grinchik Vladimir G. Andrejev Galina M. Zayats Yury N. Grinchik A. V. Luikov Heat and Mass Transfer Institute of the National Academy of Sciences of Belarus Minsk Belarus Ryazan State Radio Engineering University Ryazan Russia Institute of Mathematics of the National Academy of Sciences of Belarus Minsk Belarus Minsk Belarus

A coordinated physicomathematical model for the propagation of a soliton-like electromagnetic pulse in a heterogeneous medium is developed in the presence of strong discontinuities in the electromagnetic field. The model is based on the reduction of Maxwell’s equations to the well-studied wave equation. When the electromagnetic pulse was specified, its amplitude modulation was taken into account, as was the nonstationary broadening of the spectral line. Conditions for matching the momentum for the first initial boundary-value problem are obtained. The time dispersion of the electrical induction is taken into account in terms of the function of signal conditioning which takes account of the broadening of its spectral line and integration over the continuous spectrum. With this approach, it is not necessary to neglect spatial derivatives, and also to use spatial nonlocal relations to take account of the effect of surface charge, surface current, and spatial dispersion of electrical induction at the interfaces of adjacent media.

关键词： Strong Discontinuities in the Electromagnetic Field Nonstationary Broadening of the Spectral Line Surface Charge Surface Current Electromagnetic Wave Heterogeneous Medium soliton-like Electromagnetic Pulse Induced Surface Charge