基于可移动角点的航空和地面LiDAR数据配准

针对航空和地面LiDAR数据配准中点云数据的共轭特征较少且精度差异较大的问题,提出了一种基于可移动角点的航空和地面LiDAR数据配准方法:从航空和地面LiDAR数据中分别提取相应的建筑物角点,采用6参数模型对角点进行初始配准;以地面角点为参照,利用迭代移动方法对误差较大的航空角点进行修正;最后根据移动后的航空和地面角点计算获得点云配准关系。实验结果表明,该文方法可取得较好的点云配准效果,角点修正后能有效提升点云配准精度,适合于含有角点特征的航空和地面LiDAR数据配准。     

Analytical formulas for the geometric and inertia quantities of the largest removable blocks around tunnels

This paper presents algorithms for determining the vertices of the maximum removable block (MB) created by a joint pyramid (JP) around a tunnel when discontinuities are fully persistent. It is shown that an MB cannot be formed by more than 4 discontinuities and this drastically limits the proliferation of rock blocks that need to be analysed. The non‐convex block obtained after the MB is tunnelled through (real maximum block, RMB) is partitioned into a set of tetrahedra, and procedures are given for determining the vertices of these tetrahedra. Geometric and inertia quantities needed for stability analysis and support/reinforcement design are determined as functions of the calculated vertices' co‐ordinates. These quantities are: RMB's volume, face areas, perimeter of the excavated surface, centroid and inertia tensor. The algorithms for their calculation are at least two times faster than other algorithms previously proposed in other applications. It is shown that the formulations presented by Goodman and Shi for translational analysis and by Tonon for rotatability analysis can be used to analyse the RMBs using the geometric quantities presented. A numerical example is presented among those used to verify these analytical procedures and their implementation. Copyright © 2006 John Wiley & Sons, Ltd.     

野外组装可移动式防直击雷装置的研究

通过对9m×9m的实际接地网进行计算,对于二类和三类防雷建筑物,可以应用当环形接地网的等效面积大于78.5m2后,采取不计接地网接地电阻的设计方法来实现野外可移动式接地网设计,并将避雷针和避雷线组合的接闪器设计成标构件,方便组装,实现野外组装可移动式防直击雷装置.     

Dual high‐strength steel eccentrically braced frames with removable links

Structural damage in buildings designed according to the dissipative design philosophy can be significant, even under moderate earthquakes. Repair of damaged members is an expensive operation and may affect building use, which in turn increases the overall economic loss. If damage can be isolated to certain dissipative members realized to be removable following an earthquake, the repair costs and time of interruption of building use can be reduced. Dual structural configurations, composed of a rigid subsystem with removable ductile elements and a flexible subsystem, are shown to be appropriate for the application of removable dissipative element concept. Eccentrically braced frames with removable links connected to the beams using flush end‐plate bolted connections are investigated as a practical way of implementing this design concept. High‐strength steel is used for members outside links in order to enhance global seismic performance of the structure by constraining plastic deformations to removable links and reducing permanent drifts of the structure. Copyright © 2008 John Wiley & Sons, Ltd.     

基坑支护可拆型锚杆技术研究及应用

为了避免给周围后续工程造成施工障碍和引起法律上的纠纷,基坑支护中的临时锚杆在失去作用后应将其拆除。通过对锚杆荷载传递特性的分析和在现场原型试验研究的基础上,提出了一种仅拆除拉杆材料的可拆型锚杆技术。该技术通过在拉杆材料和注浆体之间设置隔离措施来拆卸锚杆,并通过带传力杆的承载体将锚拉力分散传递于注浆体中。工程实例表明该技术方法简单可行,且由于受力合理,可拆型锚杆的技术性能也较普通锚杆明显有所提高。     

水产用微生态制剂耐药性评估及耐药相关遗传元件检测

以市场上购买的9种水产用微生态制剂为研究对象,采用琼脂稀释法筛选其中的耐药菌株,运用微量肉汤稀释法检测分离菌株对庆大霉素、恩诺沙星、诺氟沙星、氟苯尼考、磺胺嘧啶、磺胺甲基嘧啶、四环素、土霉素、万古霉素9种抗生素的耐药性,结合聚合酶链式反应分析耐药菌株携带的耐药基因和可移动遗传元件(接合性质粒遗传标记、转座子、整合子和插入序列),为微生态制剂的安全生产与监测提供参考。结果显示,9种微生态制剂中都存在耐药菌株,100株分离菌株对除恩诺沙星以外的8种抗生素都存在不同程度的耐药, 46%的株菌同时携带氟喹诺酮类、酰胺醇类、磺胺类、四环素类、氨基糖苷类和糖肽类耐药基因,且有15株菌同时携带整合子-基因盒、质粒、转座子和插入序列,携带两种及两种以上可移动遗传原件的比例为95%。微生态制剂产品可能存在一定的安全隐患,应加强质量监测和市场监管。     

可回收式锚索试验研究

在城市建筑基坑支护中．常规锚索由于不回收而侵犯到临近地下空间的产权．其应用将会逐步得到限制,可回收式锚索将是解决这一问题的有效手段．在其使用功能完成后可以将锚索体顺利地从钻孔内全部回收,在今后的城市建设中将会有着广阔的应用前景。在综合国内外相关研究成果的基础上,开发出压力分散型回收式锚索和压力型回收式锚杆,并通过现场试验对其结构型式的合理性、承载力以及回收性能进行了验证。     

YXW-2000型液压铣轮机的研制

针对国内山地信号塔基桩孔单纯依靠人工通过水磨钻结合风镐破碎,耗时久,而且危险系数大,所以市场急需一种能够减轻人工劳动强度,安全系数高,开孔破碎速度快,适合人工搬运、可拆卸的设备。目前常用的平地基桩开孔设备主要有：竖井钻机、反井钻机和竖井掘进机等,这些设备质量及外形尺寸大,搬运困难,对复杂地形和山地条件适应性差。根据以上现状,研发了一款YXW-2000型液压铣轮机,该设备结构布置合理,功能齐全,它能有效地改善山地基桩孔施工的机械化程度,降低工人劳动强度,提高设备运行的安全性。本文主要介绍液压铣轮机的主要技术参数、结构布局特点及液压系统。经试验表明,YXW-2000型液压铣轮机能满足钻孔施工的机械化需求,可解体性好,搬运方便,具有良好的应用前景。     

SH波在浅埋可移动圆柱形刚性夹杂处的散射与地震动

采用复函数、多极坐标法研究了含有可移动圆柱形刚性夹杂的弹性半空间对SH波的散射问题。构造一个能自动满足含可移动刚性圆柱的弹性半空间自由表面上应力为零的边界条件的散射波,应用可移动圆柱形刚性夹杂的运动条件来确定该散射波。最终则可将求解问题归结为求解一个无穷代数方程组,采用截断有限项的方法对其进行求解。给出了地表位移幅值的数值结果,并讨论了各种参数对它的影响。