风暴潮作用下黄河水下三角洲斜坡稳定性研究

斜坡失稳是河口海岸环境中典型的灾害地质现象之一,其对采油平台、海底管线和电缆的危害性是巨大的。本文以黄河三角洲地区埕岛油田典型海域为研究对象,通过地球物理探测和工程地质钻探获取了10m深度范围内海底土体的分层情况和各土层的物理力学特征,利用GEO-SLOPE/W软件对其水下斜坡的稳定性进行了定量计算。结果显示,极端海况下,水下斜坡表层土体存在产生滑移破坏的可能。另外,对该区海底斜坡失稳的机理进行了探讨,认为风暴潮引起的巨浪是其主要诱因。     

Modulation and enhancement of photonic spin Hall effect with graphene in broadband regions

The photonic spin Hall effect(SHE)holds great potential applications in manipulating spin-polarized photons.However,the SHE is generally very weak,and previous studies of amplifying photonic SHE were limited to the incident light in a specific wavelength range.In this paper,we propose a four-layered nanostructure of prism-graphene-air-substrate,and the enhanced photonic SHE of reflected light in broadband range of 0 THz–500 THz is investigated theoretically.The spin shift can be dynamically modulated by adjusting the thickness of air gap,Fermi energy of graphene,and also the incident angle.By optimizing the structural parameter of this structure,the giant spin shift(almost equal to its upper limit,half of the incident beam waist)in broadband range is achieved,covering the terahertz,infrared,and visible range.The difference is that in the terahertz region,the Brewster angle corresponding to the giant spin shift is larger than that of infrared range and visible range.These findings provide us with a convenient and effective way to tune the photonic SHE,and may offer an opportunity for developing new tunable photonic devices in broadband range.