沈阳市某深基坑支护工程的设计与施工

本文以开挖深度为11m的沈阳市某深基坑支护工程为例,对其所在区域的场地条件、周边环境及工程地质条件进行了具体的分析,提出采用钻进过程中遇障碍可以返回的水泥土地锚结构体复合支护方案。克服了传统锚杆工艺施工时遇障碍就得浪费钻杆的缺点,遇到障碍时返回,也保证了相邻建筑物的安全。     

On extending the concept of double negativity to acoustic waves

INTRODUCTION At this moment, novel concepts of “negative” media, having negative refraction and/or “double negativity” and their physical consequences and plausible applications are drawing considerable at- tention from the science and engineering community. In the past few years, considerable progress has been made in electromagnetic (EM) waves. It is our wish to generalize such concepts to acoustic waves. Since the concept of negative refraction, negative constitutive relationships…