针对圆柱壳结构的减振问题, 本文提出一种局域共振型圆柱壳类声子晶体结构, 通过在圆柱壳圆周方向布置弹簧振子实现。该声子晶体的能带结构研究结果表明, 该结构能够形成两条低频带隙, 一条带隙的起始频率低至650 Hz, 带宽为330 Hz, 另一条带隙具有更低的频率范围, 为0~371 Hz, 带隙的形成是由于圆柱壳和弹簧振子振动的耦合。进一步分析了声子晶体的圆柱壳质量与弹簧振子的质量比、弹簧振子的刚度和元胞宽度对带隙的影响。对有限周期圆柱壳结构的传输特性分析, 验证了局域共振型圆柱壳声子晶体在带隙范围内的抑制振动的能力。研究结果为圆柱壳结构的减振问题提供了理论参考。

Laser speckle contrast imaging (LSCI) is an optical imaging method, which can monitor microvascular flow variation directly without addition of any ectogenous dye. All the existing laser speckle contrast analysis (LASCA) methods are a combination of spatial and temporal statistics. In this study, we have proposed a new method, Gaussian kernel laser speckle contrast analysis (gLASCA), which processes the raw images primarily with the Gaussian kernel operator along the spatial direction of blood flow. We explored the properties of gLASCA in the simulation and animal cerebral ischemia perfusion model. Compared with the other existing speckle processing methods based on spatial, temporal, spatial-temporal or anisotropic linear structure; the present gLASCA method has a high spatial-temporal resolution to respond the change of velocity especially in microvasculature. Besides, the gLASCA method obtains approximately 10.2% and 7.1% higher contrast-to-noise ratio (CNR) over the anisotropic linear method (aLASCA) in the simulation and experiment models. For these advantages, gLASCA could be a better method for local microvascular laser speckle imaging in terms of cerebral ischemia reperfusion, spreading depression and brain injury diseases.