This paper investigates the chemical reaction and thermal radiation effects on unsteady MHD free convective flow past a vertical porous plate in the presence of heat absorption/generation.The novelty of present invest...This paper investigates the chemical reaction and thermal radiation effects on unsteady MHD free convective flow past a vertical porous plate in the presence of heat absorption/generation.The novelty of present investigation is that the temperature and concentration of the plate are span wise cosinusoidally unsteady with time.The second order perturbation technique is employed to study the non-linear partial differential equations which govern the fluid flow.The effects of magnetic parameter,radiation,Eckert number,Schmidt number and chemical reaction parameters on velocity,temperature and concentration distributions as well as skin friction coefficients,the rate of heat transfer and the rate of mass transfer are discussed through figures and tables.It is noticed that the Nusselt number declines with rising values of Prandtl and Eckert numbers.展开更多
This paper focuses on the jamming problem of bistatic synthetic aperture radar (BiSAR), and a jamming method against BiSAR based on modulation theory is proposed. The proposed jamming method modulates the BiSAR signal...This paper focuses on the jamming problem of bistatic synthetic aperture radar (BiSAR), and a jamming method against BiSAR based on modulation theory is proposed. The proposed jamming method modulates the BiSAR signal with the cosinusoidal phase to generate multi-false targets in range, and further rotates the jammer to generate multi-false targets in azimuth. The range multi-false targets and azimuth multi-false targets form the two-dimensional cover jamming or deception jamming, which can protect the important targets efficiently. The number of false targets, the interval of false targets, and the jamming square can be adjusted flexibly by setting different range jamming parameters and azimuth jamming parameters. The jamming performance and the choosing criteria of jamming parameters are also discussed. Finally, the simulated data verify the effectiveness of the jamming method.展开更多
文摘This paper investigates the chemical reaction and thermal radiation effects on unsteady MHD free convective flow past a vertical porous plate in the presence of heat absorption/generation.The novelty of present investigation is that the temperature and concentration of the plate are span wise cosinusoidally unsteady with time.The second order perturbation technique is employed to study the non-linear partial differential equations which govern the fluid flow.The effects of magnetic parameter,radiation,Eckert number,Schmidt number and chemical reaction parameters on velocity,temperature and concentration distributions as well as skin friction coefficients,the rate of heat transfer and the rate of mass transfer are discussed through figures and tables.It is noticed that the Nusselt number declines with rising values of Prandtl and Eckert numbers.
基金supported by the National Defense Pre-research Program during the 13th Five-Year Plan(30603050303 301020302)
文摘This paper focuses on the jamming problem of bistatic synthetic aperture radar (BiSAR), and a jamming method against BiSAR based on modulation theory is proposed. The proposed jamming method modulates the BiSAR signal with the cosinusoidal phase to generate multi-false targets in range, and further rotates the jammer to generate multi-false targets in azimuth. The range multi-false targets and azimuth multi-false targets form the two-dimensional cover jamming or deception jamming, which can protect the important targets efficiently. The number of false targets, the interval of false targets, and the jamming square can be adjusted flexibly by setting different range jamming parameters and azimuth jamming parameters. The jamming performance and the choosing criteria of jamming parameters are also discussed. Finally, the simulated data verify the effectiveness of the jamming method.
