No abstract

In ground static target detection, polarimetric high-resolution radar can distinguish the target from the strong ground clutter by reducing the clutter power in the range cell and providing additional polarimetric features. Since the energy of a target is split over several range cells, the resulting detection problem is called polarimetric range extended target (RET) detection, where all target scattering centers should be considered. In this paper, we propose a novel polarimetric RET detection method via adaptive range weighted feature extraction. Specifically, polarimetric features of range cells are extracted, and a pretrained attention-mechanism-based module is used to adaptively calculate range cells weights, which are used to accumulate the range cells features as detection statistics. While calculating weights, both amplitude and polarimetric features are considered. This method can make the most of polarization information and improve the accumulation effect, thus increasing the discrimination between targets and clutter. The effectiveness of the proposed method is verified compared to both popular energy-domain detection methods and existing feature-domain detection methods, and the results show that our method exhibits superior detection performance. Moreover, we further analyze our method on different target models and different clutter distributions to prove that our method is suitable for different types of targets and clutter.

Aluminum powder with high explosive sensitivity, strong detonation performance and low price has become the first choice fuel for fuel air explosives. Design three types of exhaust schemes for specific powder operation spaces, and use CFD simulation technology to study the flow field and dust removal characteristics of the three schemes. The results show that the bottom ventilation scheme has the best dust removal effect, the characteristic time of dust removal is 9.4s, and the maximum dust concentration is 85g/m3. And the characteristic flow field range of the bottom exhaust scheme is the smallest (4.12m×3.05m), which indicates bottom scheme has the least disturbance to the spatial flow field, so this scheme should be selected for ventilation and dust removal design. In addition, the function relationship between the wind pressure and the characteristic dust removal time is obtained by setting different wind pressures, which provides a basis for the design of the graded ventilation dust removal side according to the design.