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Simulation research of bionic image intensifier based on the retina structure of elephant-nose fish

Zhang Hongxia, Jin Qingwen, Li Peng, Jia Dagong, Liu Tiegen

Optica Applicata

2020

Vol. 50, nr 4

551--566

Enhancing image brightness under low light conditions is crucial. The traditional night vision technology depends on the development of photoelectric materials and accurate image processing algorithms. Inspired by the structure of elephant-nose fish, we construct a bionic image intensifier (BII) model. The BII is a planar array based on the concentrating principle of the compound parabolic concentrator (CPC). This solution is based on pure optical design and independent. Through light tracing, the simulation results show that the brightness of the image is improved and good image uniformity is obtained. Quantitative analysis of the geometric concentration ratio (GCR) and the image uniformity is used to optimize CPC structure parameters. At the same time, we also discuss the influence of CPC structural parameters on image continuity, uniformity and geometric concentration ratio. The optimization results are as follows: the input port diameter is 50 μm, the output port diameter is 10 μm, the height is 90 μm, the GCR is 5.61, and the image uniformity is 95.30%. The comprehensive performance of the BII achieves the best.

Aerodynamic performance of a new double-flap wing sail

Li Dongqin, Zhang Yili, Li Peng, Dai Jingjing, Li Guohuan

Polish Maritime Research

2019

nr 4

61--68

As a type of natural energy resource, wind power is used in the modern implementation of wind-assisted technologies as a method for reducing the fuel consumption and environmental pollution of ocean-going ships. In order to promote the full usage of ocean wind energy for cargo ships, an innovative type of ship propulsion-assisted wing sail is proposed in this paper. The propulsion efficiency of this new wing sail can be increased by enlarging its area in both the transverse and vertical directions in good weather conditions, and it can be folded up automatically in poor weather conditions, improving the sailing safety of the ship. The sail parameters relating to the gaps and rotation angles between different parts of the wing sail are compared, and the values giving the best aerodynamic performance are identified using CFD simulation technology. The results for the lift and drag coefficients for the new wing sail at different attack angles are also compared with those of traditional aerofoil sails, including an arc-shaped rigid sail and a variable-camber sail proposed in 2015. From the viewpoint of the sailing performance of the vessel, our results demonstrate that this new type of wing sail has good aerodynamic performance and can reduce fuel costs for commercial vessels.