21,935 research outputs found
Optimizing the flight route of UAV using biology migration algorithm
Funding Information: This work is supported by the National Natural Science Foundation of China under Grants 62006103 and 61872168, in part by the Jiangsu national science research of high education under Grand 20KJB110021.Peer reviewedPublisher PD
Suppressing longitudinal double-layer oscillations by using elliptically polarized laser pulses in the hole-boring radiation pressure acceleration regime
It is shown that well collimated mono-energetic ion beams with a large
particle number can be generated in the hole-boring radiation pressure
acceleration regime by using an elliptically polarized laser pulse with
appropriate theoretically determined laser polarization ratio. Due to the
effect, the double-layer charge separation region is
imbued with hot electrons that prevent ion pileup, thus suppressing the
double-layer oscillations. The proposed mechanism is well confirmed by
Particle-in-Cell simulations, and after suppressing the longitudinal
double-layer oscillations, the ion beams driven by the elliptically polarized
lasers own much better energy spectrum than those by circularly polarized
lasers.Comment: 6 pages, 5 figures, Phys. Plasmas (2013) accepte
Flexible constant force grinding of rare earth metal ingot
The rare earth metal ingots obtained by molten salt electrolysis method have oxide layers, salt layers, and other impurities on the surface, which require polishing processing. However, currently, manual polishing processing has problems such as low processing efficiency and resource waste. By designing a flexible end effector and adopting a parallel fuzzy Proportion Integration Differentiation (PID) control strategy for constant force control of the end effector, automation and high efficiency of rare earth metal ingot grinding are achieved
Flexible constant force grinding of rare earth metal ingot
The rare earth metal ingots obtained by molten salt electrolysis method have oxide layers, salt layers, and other impurities on the surface, which require polishing processing. However, currently, manual polishing processing has problems such as low processing efficiency and resource waste. By designing a flexible end effector and adopting a parallel fuzzy Proportion Integration Differentiation (PID) control strategy for constant force control of the end effector, automation and high efficiency of rare earth metal ingot grinding are achieved
2-D DOA Estimation for L-Shaped Array With Array Aperture and Snapshots Extension Techniques
A two-dimensional (2-D) direction of arrival estimation method for L-shaped array with automatic pairing is proposed. It exploits the conjugate symmetry property of the array manifold matrix to increase the effective array aperture and the number of virtual snapshots simultaneously, and then applies the principle of MUSIC to construct an angle cost function and transforms the conventional 2-D search into 1-D via a Rayleigh quotient, which can greatly reduce the computation complexity. Finally, the azimuth and elevation angles are estimated without pair matching. Simulation results show that the proposed method has a better performance and can resolve more sources than some existing computationally efficient methods
Surface phase separation in nanosized charge-ordered manganites
Recent experiments showed that the robust charge-ordering in manganites can
be weakened by reducing the grain size down to nanoscale. Weak ferromagnetism
was evidenced in both nanoparticles and nanowires of charge-ordered manganites.
To explain these observations, a phenomenological model based on surface phase
separation is proposed. The relaxation of superexchange interaction on the
surface layer allows formation of a ferromagnetic shell, whose thickness
increases with decreasing grain size. Possible exchange bias and softening of
the ferromagnetic transition in nanosized charge-ordered manganites are
predicted.Comment: 4 pages, 3 figure
Incompressible SPH simulation of wave interaction with porous structure
In this paper an incompressible Smoothed Particle Hydrodynamics (ISPH) method is applied to investigate the flow motion in and around the porous structure. In order to describe in a simple and effective way the flow through the interface between the porous region and pure fluid region within the SPH framework, a heuristic boundary treatment method has been proposed. The ISPH model is first verified against a theoretical model of wave propagation over a porous bed and then further validated by comparing the predicted wave surface profiles and flow velocity fields with the experiment data for a typical case of flow motion around and inside a submerged porous structure. The good agreement has demonstrated that the improved ISPH model developed in this work is capable of modelling wave interaction with porous structures
- …