Experimental study on bubble pulse features under the combined action of horizontal and vertical walls

The pulse features of a bubble have a close connection with the boundary condition. When a bubble moves near a rigid wall, it will be attracted by the Bjerknes force of the wall, and a jet pointing at the wall will be generated. In real application, the bubble may move under the combined action of walls in different directions when it forms at the corner of a pipe or at the bottom of a dam. The motion of the bubble shows complex and nonlinear characteristics under these conditions. In order to investigate the bubble pulse features near complex walls, a horizontal wall and a vertical wall are put into the experimental water tank synchronously, and an electric circuit with 200 voltages is designed to generate discharge bubbles, and then experimental study on the bubble pulse features under the combined action of horizontal and vertical walls is carried out. The influences of the combined action of two walls on the bubble shape, pulse period, moving trace and inside jet are obtained by changing the distances from bubble center to the two walls. It aims at providing references for the relevant theoretical and numerical research.     

美国阿拉斯加金矿资源特征及远景区预测

阿拉斯加位于北美洲西北部,是美国最大的州,经历了约2亿年的地质构造演化,具有丰富的矿产资源,尤其是以岩金为主的黄金资源。中国对阿拉斯加地区研究较少,中文资料匮乏。通过研究,为保护中国黄金资源和推动中国企业在阿拉斯加“走出去”走出去提供了基础资料。收集资料发现,阿拉斯加金矿资源主要分布在东南部、西南部、中南部、中部和西部地区。金矿类型分为造山型、深成岩体型、侵入相关型、石英脉型、砂金型。通过分析阿拉斯加地质资料确定了4个远景区,由2个 Ⅰ 级远景区、1个 Ⅱ 级远景区和1个 Ⅲ 级远景区组成。建议中国企业关注 Ⅰ 级远景区。阿拉斯加金矿资源可利用性评价良好,值得中国企业关注。     

新型压电摩擦阻尼器的有限元分析及试验研究

利用压电陶瓷的压电效应,研发出一种基于半主动控制的新型压电摩擦阻尼器,介绍其构造和工作原理。建立新型压电摩擦阻尼器的ABAQUS有限元模型,得出阻尼器在不同工况下的滞回曲线,并进行其滞回性能试验,用试验值验证阻尼器有限元模型的相似性,两者得到的阻尼器摩擦力变化趋势相近;采用ANSYS建立安装有新型压电摩擦阻尼器的输变电塔模型,利用MATLAB计算输变电塔模型各层的加速度响应,验证新型压电摩擦阻尼器在实际结构中的摩擦耗能性能,为其工程应用提供理论依据。     

Seismoelectric and electroseismic responses to a point source in a marine stratified model

We investigate the seismoelectric/electroseismic wavefields excited by a point source in an air/seawater/three-layered porous medium configuration containing a hydrocarbon layer. The results show that if an explosive source for excitation is used, receivers at seafloor can record the coseismic electromagnetic fields accompanying the P, S, fluid acoustic waves and the interface responses converted from the acoustic waves at seafloor interface and from the seismic waves at the interfaces beneath the seafloor. Employing a vertical electric dipole source shows that, with the exception of the interface responses converted from electromagnetic waves at seafloor, the interface responses converted from transmitted electromagnetic waves at the interfaces beneath the seafloor can also be identified. Given that the strength of the explosive source is within excitation capability of industry air guns, the generated interface responses from the hydrocarbon layer can be detected by current electromagnetic sensors considering the low ambient noise at the seafloor. Our results demonstrate the feasibility of the seismoelectric method applied to marine hydrocarbon exploration. Electroseismic modelling results suggest that it is not practical to employ this method to prospect marine hydrocarbon layer due to the weak interface response signal, unless a much larger current is injected into seafloor.     

Ⅱ类水体光学特性的剖面测量方法

剖面测量方法是国际上推荐测量水体表观光学参数的首选方法，文章在简要介绍剖面测量原理的基础上，根据Ⅱ类水体特点对应用算法进行改进，并给出其应用效果。     

麻阳陆相盆地东缘侏罗纪地层研究

本文对麻阳陆相盆地东缘侏罗纪地层的岩石特征、微体化石、地层层序、生物组合特征以及沉积环境进行了较系统的研究,提高了湖南西部侏罗纪地层的研究程度。     

苏北东部海域辐射沙洲研究的新思路

苏北东部海域辐射沙洲以往仅侧重于外动力方面的研究，这里提出开展内动力与外动力同步研究的新思路，指出两者的结合点是旋扭运动，要在以往外动力研究的基础上，加强地震震中研究、地形变监测、地应力实测等方面内容，以确定该区不同层圈、不同介质条件下是否存在同一的旋扭运动。上述思路的实施，有利于地理学与地质学研究的沟通和溶合，同时提出地震往往伴随旋扭现象的事实，丰富了地震学的研究内容，其研究成果将为多方面的开发辐射沙洲提供基础资料。     

Remediation and monitoring of a highway across an active landslide at Trevor, North Wales

In March 1989, a moderately steep slope forming sidelong ground below the B5434 Trevor to Froncysyllte Road failed after a period of exceptionally heavy rainfall and severed the highway. A long history of ground movements together with river erosion at the toe and a change in the groundwater regime within the slope created the preconditions for landslide. Site investigations characterised the ground conditions and identified the active slip surface within the compound landslide terrain. The permanent remedial measures adopted proved to be of considerable practical interest involving a bored pile anchored wall with foundations socketed into a deep sandstone foundation stratum. The anchored wall was designed to safeguard the highway and it was anticipated that deloading the slope would reduce the capacity for further movement. The wall achieved the design objective but progressive downslope movements resumed about one year after construction. They continue spasmodically to the present time with rates approaching 9 mm per year both laterally and vertically and although they affect the neighbouring areas, the highway corridor remains intact. The response of load cells attached to the ground anchors reveal two unusual patterns of increasing loads. At the eastern end of the wall, moderate load gains clearly relate to landsliding with reactivation along the existing slip surface and consequent removal of support to the wall as the ground progressively fails in a downslope direction. However, anomalous increases in loads recorded at the western end of the wall have proved more difficult to explain. They may be due either to a build up of water pressure behind the downhill portion of the wall or to localised weak ground conditions or swelling of degraded mudstones behind the wall. Monitoring of the load cells will continue in order to ensure the ongoing integrity of the highway.     

西方经济地理学关系范式与演化范式比较研究

伴随着国际经济组织形式的多样化和社会科学理论的多元化,近20 多年来西方经济地理学出现了多种理论转向,为解释新的经济活动空间现象提供了多维视角.其中,关系转向和演化转向的研究近来显得格外活跃,都试图建立自己的理论框架,并形成了关系经济地理学和演化经济地理学两种理论范式.两种范式在一些理论假设上有很多相似之处,但对二者的比较研究却十分少见.为了更加透彻地了解两种范式的理论内涵,在对两种理论范式的产生背景、主要观点和核心概念介绍的基础上,从理论假设、核心问题、核心概念和理论构建等方面对两种范式进行了对比,进而分析了西方经济地理的走向及对中国经济地理发展的启示.     

光纤布拉格光栅用于海水盐度监测初探

海水入侵问题已波及中国沿海的9个省份,其中海水入侵最为严重的山东、辽宁两省入侵面积超过2000 km2。在气 候变化和人类活动等作用因素的加剧影响下,海水入侵问题不可避免,因此,海水入侵的监测和防治是解决问题的关键, 具有十分重要的意义。本文针对目前海水入侵监测技术存在的问题,提出了一种可大范围实时原位监测海水盐度的光纤布 拉格光栅（FBG） 方法,并设计试验对三种FBG盐度测试方案的可行性进行了对比研究。试验结果表明：FBG技术应用于 海水盐度监测具有一定可行性;利用能量补偿技术的两点串FBG测试效果最佳,灵敏度及稳定性在三种方案中均最好。基 于FBG的海水盐度监测方法可以弥补目前常用的水化学法和物探法存在的不足,为海水入侵的监测和预防提供了一种先 进、高效的手段。