基于低比特量化神经网络的红外目标识别方法及其FPGA实现

红外目标识别系统成为航空航天、无人驾驶等军事和民用领域中一项至关重要的技术。红外目标识别算法是红外目标检测识别系统中的核心之一。传统红外目标识别技术往往依赖人为的特征选择，无法对复杂困难的红外目标实现高效、准确的识别。本文提出了训练中反量化与通道级量化相结合的量化策略，有效减小量化误差对网络模型性能的影响。实验结果表明:本文提出的低比特量化算法在红外数据集上有着优异的表现。在硬件部署方面，本文提出了更加高效的卷积计算单元，提高了硬件资源的利用率，同时也达到了更高的峰值性能。最终，在PYNQ-Z2嵌入式现场可编程门阵列(FPGA)上进行验证，系统在150 MHz的时钟频率下达到了90.6 GOP/s的峰值吞吐率，其功耗为2.5 W。     

脉冲磁流体发电技术研究进展

本文总结和阐述了现有脉冲磁流体发电机的类型及其国内外研究进展,同时对磁流体发电过程中的关键技术和科学问题(近电极压降、边界层分离、Hartmann效应、发电系统建模、性能分析、高磁雷诺数、强电磁效应、阻抗匹配等)进行了综述总结,以期掌握磁流体动力学行为及能量转化机理,提升发电机性能,并介绍了在航空航天领域的三种主要应用方式：磁流体能量旁路、超燃冲压发动机驱动的磁流体发电及表面磁流体发电。最后，对脉冲磁流体发电技术研究的发展趋势进行了总结和展望,旨在对其实用化进程提供指导和借鉴意义。     

Small-scale solar jet formation and their associated waves and instabilities

Studies on small-scale jets’ formation, propagation, evolution, and role, such as type I and II spicules, mottles, and fibrils in the lower solar atmosphere’s energetic balance, have progressed tremendously thanks to the combination of detailed observations and sophisticated mathematical modelling. This review provides a survey of the current understanding of jets, their formation in the solar lower atmosphere, and their evolution from observational, numerical, and theoretical perspectives. First, we review some results to describe the jet properties, acquired numerically, analytically and through high-spatial and temporal resolution observations. Further on, we discuss the role of hydrodynamic and magnetohydrodynamic instabilities, namely Rayleigh–Taylor and Kelvin–Helmholtz instabilities, in jet evolution and their role in the energy transport through the solar atmosphere in fully and partially ionised plasmas. Finally, we discuss several mechanisms of magnetohydrodynamic wave generation, propagation, and energy transport in the context of small-scale solar jets in detail. This review identifies several gaps in the understanding of small-scale solar jets and some misalignments between the observational studies and knowledge acquired through theoretical studies and numerical modelling. It is to be expected that these gaps will be closed with the advent of high-resolution observational instruments, such as Daniel K. Inouye Solar Telescope, Solar Orbiter, Parker Solar Probe, and Solar CubeSats for Linked Imaging Spectropolarimetry, combined with further theoretical and computational developments.