3D stability analysis method of concave slope based on the Bishop method

In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop method was employed. The sliding body was divided into strips in a three-dimensional model, and the lateral earth pressure was put into mechanical analysis and the three-dimensional stability analysis methods applicable for circular sliding in concave slope were deduced. Based on geometric structure and the geological parameters of a concave slope, the influence rule of curvature radius and the top and bottom arch height on the concave slope stability were analyzed. The results show that the stability coefficient decreases after growth, first in the transition stage of slope shape from flat to concave, and it has been confirmed that there is a best size to make the slope stability factor reach a maximum. By contrast with average slope, the stability of a concave slope features a smaller range of ascension with slope height increase, which indicates that the enhancing effect of a concave slope is apparent only with lower slope heights.

Three‑Dimensional Ordered Mesoporous Carbon Spheres Modified with Ultrafine Zinc Oxide Nanoparticles for Enhanced Microwave Absorption Properties

Currently,electromagnetic radiation and interference have a significant effect on the operation of electronic devices and human health systems.Thus,developing excellent microwave absorbers have a huge significance in the material research field.Herein,a kind of ultrafine zinc oxide(ZnO)nanoparticles(NPs)supported on three-dimensional(3D)ordered mesoporous carbon spheres(ZnO/OMCS)is prepared from silica inverse opal by using phenolic resol precursor as carbon source.The prepared lightweight ZnO/OMCS nanocomposites exhibit 3D ordered carbon sphere array and highly dispersed ultrafine ZnO NPs on the mesoporous cell walls of carbon spheres.ZnO/OMCS-30 shows microwave absorbing ability with a strong absorption(−39.3 dB at 10.4 GHz with a small thickness of 2 mm)and a broad effective absorption bandwidth(9.1 GHz).The outstanding microwave absorbing ability benefits to the well-dispersed ultrafine ZnO NPs and the 3D ordered mesoporous carbon spheres structure.This work opened up a unique way for developing lightweight and high-efficient carbon-based microwave absorbing materials.

GaN基LED表面三维凹球结构的制备及其发光增强

以紫外曝光技术为基础,得到了欠曝光条件下的三维凹球结构,结合菲涅尔衍射效应和邻近效应开发了一种制备密排三维周期性凹球结构的方法,并重点研究了掩膜版类型和光刻胶厚度对曝光图形的影响。实验结果表明,采用六方密排结构的明场掩膜图案,当光刻胶厚度为1.3~1.5μm时,可以得到周期为3~5μm、占空比接近100%的三维凹球结构阵列。该三维凹球结构阵列在LED发光增强及微透镜阵列等方面有广阔的应用前景,并在实验中实现了GaN基LED发光增强163.4%,通过角分辨分析得到LED发光在法线方向的30°~65°和115°~150°增强最为明显,扩大了LED光出射的角度,对LED作为显示器件增大可视角度具有重要意义。