吸湿性是大气颗粒物最重要的物理化学性质之一，直接影响着实际大气条件下气溶胶的粒径、形貌、成分、化学反应活性和光学性质，从而最终影响着气溶胶的环境与气候效应。现有的吸湿性测量技术大多需要假设颗粒物为球形，且灵敏度较低，无法准确测定非球形颗粒物或吸湿性较低颗粒物的吸湿性。蒸汽吸附分析仪通过测量颗粒物的质量随相对湿度的变化来研究其吸湿性，这种新方法不仅对颗粒物的形貌没有要求，而且具有卓越的灵敏度。本文首先介绍了这种气溶胶吸湿性测量新方法的工作原理和技术特点，然后重点介绍了这种新方法在大气科学、地球与行星科学、医用气溶胶等多个领域中的应用。最后，在简要总结蒸汽吸附分析仪在大气颗粒物吸湿性研究上的优越性和局限性的基础上，对未来可开展的吸湿性研究工作提出了一些设想。

Optical bound states in the continuum (BICs) have recently stimulated a research boom, accompanied by demonstrations of abundant exotic phenomena and applications. With ultrahigh quality (Q) factors, optical BICs have powerful abilities to trap light in optical structures from the continuum of propagation waves in free space. Besides the high Q factors enabled by the confined properties, many hidden topological characteristics were discovered in optical BICs. Especially in periodic structures with well-defined wave vectors, optical BICs were discovered to carry topological charges in momentum space, underlying many unique physical properties. Both high Q factors and topological vortex configurations in momentum space enabled by BICs bring new degrees of freedom to modulate light. BICs have enabled many novel discoveries in light–matter interactions and spin–orbit interactions of light, and BIC applications in lasing and sensing have also been well explored with many advantages. In this paper, we review recent developments of optical BICs in periodic structures, including the physical mechanisms of BICs, explored effects enabled by BICs, and applications of BICs. In the outlook part, we provide a perspective on future developments for BICs.

基于多球能谱仪开展了广州、兰州和拉萨等地区的大气中子能谱和通量测量，获取了大气中子能谱的典型特征。测量结果表明：不同地区的大气中子通量受海拔高度的影响明显，地面大气中子通量随着海拔的增加而增加。此外，基于蒙特卡罗仿真工具也可以模拟初级宇宙射线粒子在地球大气层中的核反应过程，从而计算获取大气中子能谱。大气中子能谱测量数据与仿真数据吻合良好。

Manipulating radiation is important for a variety of optoelectronic applications, such as on-chip lasers, energy-efficient grating couplers, and antennas for light detection and ranging. Although designing and optimizing those optoelectronic devices are usually believed to be an engineering-oriented task, recent research reveals that the principles underlying radiation manipulation are closely connected to the concept of topology—the study of properties that are invariant under continuous deformations. In this review, we summarize a series of advances of the physics, phenomena, and applications related to radiation manipulation, in which topological concepts were adopted. Radiation could carry energy escaping from the system, breaking the energy conservation. The non-Hermiticity of such systems brings quite different physical consequences when comparing with the Hermitian counterparts and, hence, also results in the emergence of many interesting and extraordinary phenomena. In particular, it is found that the perfect trapping of light can still be realized in such non-Hermitian systems because of the photonic realization of bound states in the continuum. The fundamental nature of bound states in the continuum has been identified to be topological: they are essentially topological defects of the polarization vector field in momentum space, depicted by a kind of topological invariant named topological charges. Therefore, manipulation of radiation channels can be realized by controlling the topological charge evolution in momentum space. It is also demonstrated that the photonic states accompanied with different topological charges generate vortex beams with unique far-field radiation patterns, and ultra-fast switching of such vortex beams is demonstrated according to this principle. The progresses of topological photonics upon light radiation show that the topology is not just mathematical convenience for depicting photonic systems, but has brought realistic consequences in manipulating light and will boost the applications of photonics and optoelectronics in many aspects.