Switchable vortex beam polarization state terahertz multi-layer metasurface

We propose a switchable vortex beam polarization state terahertz multi-layer metasurface, which consists of three-layer elliptical metal crosses, four-layer dielectrics, and two-layer hollow metal circles, which are alternately superimposed. Under the normal incidence of left-handed circularly polarized (LCP) wave and the right-handed circularly polarized (RCP) waves, the proposed structure realizes three independent control functions, i.e., focused and vortex beam, vortex beam with different topological charges, and polarization states switching, and azimuth switching of two vortex beams with different polarization states. The results show that the proposed metasurface provides a new idea for investigating the multifunctional terahertz wave modulation devices.     

Multi-function terahertz wave manipulation utilizing Fourier convolution operation metasurface

We propose a novel metasurface based on a combined pattern of outer C-shaped ring and inner rectangular ring. By Fourier convolution operation to generating different predesigned sequences of metasurfaces, we realize various functionalities to flexible manipulate terahertz waves including vortex terahertz beam splitting, anomalous vortex terahertz wave deflection, vortex terahertz wave splitting and deflection simultaneously. The incident terahertz wave can be flexibly controlled in a single metasurface. The designed metasurface has an extensive application prospect in the field of future terahertz communication and sensing.     

北京市居民垃圾分类情况调查浅析

采用调查问卷的形式,对北京市泰和小区、贵园南、北小区的居民和亦庄中心小学的家长进行垃圾分类知识的掌握情况,垃圾分类的态度意识,以及其对垃圾分类的处理方式等相关方面的了解.本文通过Pearson卡方检验来分析三个小区垃圾分类问题上的差异性;通过logistic回归,建立垃圾分类问题中居民的垃圾分类行为、居民的垃圾分类态度与垃圾分类知识的掌握情况之间的关系;同时,通过调查问卷来分析民众是否正确进行垃圾分类,并且分析民众将垃圾错误分类的原因何在,并提出合理有效措施以确保民众能够更好地进行垃圾分类.