随着航天回收系统应用需求越来越广，回收物质量也越来越大，对翼伞面积的要求越来越高，超大型翼伞开始受到广泛的关注，然而目前国内外对超大型翼伞的研究较少。对此，文章以超大型连续翼伞和超大型组合翼伞为研究对象，分别对其进行物理建模。采用计算流体力学（Computational Fluid Dynamics，CFD）的方法，基于k-epsilon湍流模型，分别计算在无下拉、单侧下拉、双侧下拉时超大型连续伞和超大型组合伞的气动特性。研究发现，超大型组合伞在组合处有很明显的气流补充，可以减缓流动分离的情况，增大失速迎角，更适合大攻角的飞行任务，适用范围更广。研究成果可以为以后超大型翼伞的选型提供一定的参考。

基于一种具有串并联混合腿足机构的四足可行走着陆器，为摸清其行走过程中的关节能耗问题，采用牛顿-欧拉方法进行了动力学建模研究。首先，采用D-H法建立串并联混合腿足机构的关节坐标系，进行正向运动学和逆向运动学的推导；然后在运动学模型的基础上，采用牛顿-欧拉方法建立着陆器整机的全状态动力学模型，该模型以足端相对轨迹为输入，获取着陆器在运动过程中各关节受力情况的变化曲线；最后，采用五次样条插值法规划一段运动轨迹，用ADAMS仿真软件进行着陆器虚拟样机仿真。经验证，该动力学模型理论计算数值和虚拟样机仿真数值具有相同的变化趋势，证明了模型的有效性，可以作为后续能耗模型建立和优化的基础。

采用分子动力学方法研究了氦辐照对金属钨传热性能的影响，从原子尺度分析了单晶钨与多晶钨的热导率随氦含量的变化及其微观机理。结果表明：随着氦原子从0增加至500，钨中的缺陷对数目呈先增加后减少的趋势，单晶钨中氦原子为230个时缺陷对数目达到峰值123，多晶钨中氦原子为480个时缺陷对数目达到峰值124；钨金属的晶体结构从bcc转变为bcc、fcc和hcp等多种结构共存。钨的热导率随氦含量增加波动明显，总体呈非线性减小趋势，在氦含量为0.75%时，单晶钨和多晶钨的热导率分别下降1.44%和1.3%。氦辐照下钨金属内缺陷的产生、聚集及晶体结构的变化是其热导率下降的主要原因。

We propose a scheme that utilizes weak-field-induced quantum beats to investigate the electronic coherences of atoms driven by a strong attosecond extreme ultraviolet (XUV) pulse. The technique involves using a strong XUV pump pulse to excite and ionize atoms and a time-delayed weak short pulse to probe the photoelectron signal. Our theoretical analysis demonstrates that the information regarding the bound states, initiated by the strong pump pulse, can be precisely reconstructed from the weak-field-induced quantum beat spectrum. To examine this scheme, we apply it to the attosecond XUV laser-induced ionization of hydrogen atoms by solving a three-dimensional time-dependent Schrödinger equation. This work provides an essential reference for reconstructing the ultrafast dynamics of bound states induced by strong XUV attosecond pulses.

Two-dimensional (2D) van der Waals materials have attracted tremendous attention due to their versatile physical properties and flexible manipulation approaches. Among the various types of van der Waals materials, α-In2Se3 is remarkable for its intrinsic 2D ferroelectricity and high-performance opto-electronic properties. However, the study of the α-In2Se3 system in terahertz (THz) radiation is scarce, although it is promising for electrically controlled THz field manipulation. We investigate the α-In2Se3 in different thicknesses and report that the THz generation efficiency induced by femtosecond laser pulses can be largely improved by reducing the thickness from the bulk. Furthermore, we reveal the surge current in thin film coupled with THz emission exhibits a different Auger recombination mode, which is helpful in understanding the mechanism and provides insights into the design of 2D highly efficient THz devices.