Multiaxial neutron/x-ray imaging and three-dimensional (3D) reconstruction techniques play a crucial role in gaining valuable insights into the generation and evolution mechanisms of pulsed radiation sources. Owing to the short emission time (∼200 ns) and drastic changes of the pulsed radiation source, it is necessary to acquire projection data within a few nanoseconds in order to achieve clear computed tomography 3D imaging. As a consequence, projection data that can be used for computed tomography image reconstruction at a certain moment are often available for only a few angles. Traditional algorithms employed in the process of reconstructing 3D images with extremely incomplete data may introduce significant distortions and artifacts into the final image. In this paper, we propose an iterative image reconstruction method using cylindrical harmonic decomposition and a self-supervised denoising network algorithm based on the deep image prior method. We augment the prior information with a 2D total variation prior and a 3D deep image prior. Single-wire Z-pinch imaging experiments have been carried out at Qin-1 facility in five views and four frames, with a time resolution of 3 ns for each frame and a time interval of 40 ns between adjacent frames. Both numerical simulations and experiments verify that our proposed algorithm can achieve high-quality reconstruction results and obtain the 3D intensity distribution and evolution of extreme ultraviolet and soft x-ray emission from plasma.

快速反射镜（Fast Steering Mirror，FSM）是高精密光学系统中的关键仪器，基于音圈电机（Voice Coil Actuator，VCA）驱动的柔性支撑FSM存在复杂耦合特性，导致系统模型复杂并严重影响系统的控制性能，对于该问题，本文提出了一种基于系统辨识与模型降阶的双轴积分增广滑模控制方法。首先，采用基于脉冲响应的Hankel矩阵系统辨识方法建立VCA-FSM的精确耦合模型；随后，基于平衡实现与平衡截断，在保证模型精度的前提下对所建立的高阶模型进行降阶；其次，基于降阶模型，采用现代控制理论方法设计积分增广滑模控制器，通过设计状态观测器构造滑模切换函数与控制律，并在控制设计中改进符号函数以消除滑模抖振；最后，基于VCA-FSM伺服控制系统实验平台，开展频域与时域性能测试实验。实验结果表明：本文所提控制方法相较于单轴滑模、PID控制方法，系统的闭环跟踪带宽分别提高了约50.3%，251.3%，扰动抑制带宽分别提高了约39.9%，451.9%，阶跃响应调节时间分别缩短了约29.7%，97.7%，螺旋线跟踪精度分别提高了约48.5%，97.8%，且实现了对存在强耦合特性VCA-FSM的解耦控制。本文所提控制方法充分提高了VCA-FSM的控制性能。

In an acousto-optic modulator, the electrode shape plays an important role in performance, since it affects the distribution of the acoustic field. The acousto-optic modulator based on the conventional rectangular electrode has the problems of low energy efficiency and small modulation bandwidth due to an imperfect acoustic field. In this paper, a new serrated periodic electrode has been proposed for using acousto-optic modulator transducers. The proposed electrode has the following advantages. By using serrated periodic electrodes to suppress the sidelobes, the collimation of the acoustic field in the direction perpendicular to the light incidence is improved. This makes the acousto-optic modulator have a stable diffraction efficiency fluctuation and high energy efficiency. In addition, the electrode has a large divergence angle in the direction of light incidence, so a large bandwidth can be obtained. The simulations and experiments demonstrate that the serrated periodic electrode has an increased bandwidth and high energy efficiency.