On the role of the Asian monsoon in the angular momentum and kinetic energy balances of the tropics

The balance conditions of relative angular momentum and time-mean kinetic energy and their annual variations are studied for the Northern Hemisphere tropical belt. The belt is divided into two roughly equal size parts, the monsoon and the extramonsoon regions. The data used consist of all available daily rawinsonde reports from the world areological network for the two 5-year periods 1958–63 and 1968–73.In winter, the trade winds in the monsoon and extramonsoon regions are both sources of westerly relative angular momentum for the middle latitude circulation. However, it is found that the angular momentum gained in the extramonsoon region of the Tropics is mostly destroyed by a net southward flow of mass in that region, and becomes regenerated in the monsoon region by a net northward flow of mass there. This excess of angular momentum together with the angular momentum picked up locally in the monsoon region is almost all exported across its northern boundary. It is further found that in winter the Tropics are also an important source of mean kinetic energy for middle latitudes. Again almost all export of kinetic energy was found to take place across the northern boundary of the monsoon sector. Most of this energy must be generated through the pressure gradient term inside the monsoon region itself, the transformation from transient eddy kinetic energy being very small. The proper evaluation of the pressure gradient appears to be the main stumbling block in the present study, preventing us from estimating the generation and thereby, as a residual, the frictional dissipation in the two regions.In summer, the extramonsoon region remains a source of angular momentum, but the monsoon region with its surface westerlies acts as a sink, leading to a sharp reduction (and even a midsummer reversal) of the export into middle latitudes. Also the export of mean kinetic energy almost vanishes in summer, except for a small southward transfer across the equator. The calculations for two 5-year periods give very similar estimates and thereby show the reliability of the results.Parts of this paper were presented at the International Symposium on Monsoons, March 7–12, 1977 in New Delhi, India.     

区域地质调查中对沉积混杂岩的识别与工作方法

介绍了沉积混杂岩的识别方法 , 提出了造山带沉积混杂岩区区调研究的技术路线 , 建议沉积混杂岩的制图单位采用三级划分体制 :一级为沉积混杂岩带、二级为沉积混杂岩层、三级为沉积混杂岩体。以中甸地区为例示范了这些制图单位在地质图上的表示方法。     

沪昆客专沙坡特大桥危岩落石形成机制及防治措施研究

沪昆高铁贵昆段沙坡特大桥线路左侧多处危岩落石对大桥构成一定威胁。本文在对区域地质环境和危岩体结构特征的调查的基础上,利用无人机航拍技术,查明了沙坡双线特大桥左侧山坡坡顶裂缝及围岩体的分布,研究了该处危岩落石体的形成的机制,并提出了采用梯形垛反压、清方、灌浆以及局部支挡的防治措施,取得了良好的经济效益,同时保障了沪昆客专安全、有序运营。     

War,by Conservation

In this paper I argue that there has been a critical shift towards war by conservation in which conservation, security and counter insurgency (COIN) are becoming more closely integrated. In this new phase concerns about global security constitute important underlying drivers, while biodiversity conservation is of secondary importance. This is a significant break from earlier phases of fortress conservation and war for biodiversity. In order to develop a better understanding of these shifts, this paper analyzes the existing conceptual approaches, notably environmental security which seeks to understand how resources cause or shape conflict, and political ecology approaches that focus on the struggles over access to and control over resources. However, this paper indicates the limitations of these existing debates for understanding recent shifts, which require a fresh approach. I chart the rise of the narrative I call poachers-as-terrorists, which relies on the invocation of the idea that ivory is the white gold of Jihad, a phrase which is closely associated with an Elephant Action League (EAL) report in 2012 which claimed Al Shabaab used ivory to fund its operations. This narrative is being extended and deepened by a powerful alliance of states, conservation NGOs, Private Military Companies and international organizations, such that it is shaping policies, especially in areas of US geo-strategic interest in Sub-Saharan Africa. As a result conservation is becoming a core element of a global security project, with significant implications for conceptual debates and for conservation practice on the ground.     

浅析现浇板裂缝产生原因及治理方法

近年来,随着现浇结构使用越来越广泛,但建设物现浇板板角出现裂缝的现象越来越多,笔者就板角裂缝的形成原因,进行了简要分析,并提出了其预防措施.     

多年冻土区路基尺度效应对路面结构力学响应的影响

为了研究不同尺度路基融沉作用对路面结构层力学响应的影响,建立了基于热力耦合理论的有限元模型,系统研究不同路基尺度工况下,融沉作用对不同厚度路面、不同材料基层的力学分布规律影响. 结果表明：相同的融沉条件下,整体式路基较分离式及二级路基,变形分别增大45%、64%,应力增大17.5%、21.7%. 高速公路面层由于路基较宽,地基融沉更容易向上传递,进而导致面层底部应力增大,最终造成面层的破坏. 因此,路面设计过程中保证一定的面层厚度,并采用柔性基层减小模量,可有效以降低层底应力水平,并防止基层裂缝向上反射.     

一年内列车荷载作用下冻土路基的应力分布

冻土路基土体的物理性质与温度有密切关系, 在不同的季节, 路基内的变形场和应力场会相应发生变化. 为了说明路基内变形场和应力场的季节性差异, 以青藏铁路某断面为例, 对冻土路基在有、无列车荷载两种工况下进行了数值模拟, 系统分析了两种工况下路基内的变形场和应力场特点. 结果表明: 路基修筑后, 在自重作用下会产生较大瞬时变形; 由于路基内温度场随时间变化, 路基内各点的位移也随时间发生变化, 且位移时程曲线与温度时程曲线大体呈负相关. 在有、无列车两种工况下路基竖向位移分布都是由道砟中心向路基内部逐渐减小, 但数值明显不同; 由列车荷载引起的最大竖向附加变形发生在路基顶面中心点, 在10月15日、1月15日、4月15日, 变形量分别为-4.94 mm、-3.24 mm、-2.56 mm. 对于路基底面中心点和地基浅层中心点, 由列车荷载引起的附加应力在10月15日最大、1月15日次之、4月15日最小, 附加应力最大达到19.48 kPa; 列车荷载主要影响路基上部土体应力分布, 对下部土体应力分布影响较小.     

高速公路沿线暗浜填土的勘察和评价

目前，线路勘探中对浜填土检测不够重视或缺乏有效的方法，使浜填土的处理缺乏针对性，造成不必要的浪费或工程隐患。该文探讨了在线路勘探中暗浜的勘查技术及相应评价与整治方法。     

三峡工程岩体破坏分析中面连通率研究

介绍了面连通率在岩体破坏研究中的表述方法。连通率的大小可反映破坏概率的大小。选择可能滑动面进行连通率计算方法有：多个结构面组成的折面;单个结构面的扩展面。两种面连通率均反映了在空间平面上结构面的发育程度,揭露更多隐藏的破坏性信息,有利于定量、定位分析岩体稳定性。     

谭庄-沈丘凹陷油气形成条件分析及勘探思路

谭庄-沈丘凹陷位于周口坳陷中部凹陷带,是一个中、新生代两期断陷叠合的次级构造单元,面积近2800km2.勘探证实凹陷内沉积了巨厚的中生代早白垩纪地层(分布面积2000km2),其中暗色泥岩平均厚达1250m,在多口探井中见到级别不同、层数不一、厚度不等的油气显示,并在周参10、周11、12、19等多口井见到油气流,显示了该凹陷良好的勘探前景;但至今仍未取得实质性的突破,表明它具有一定的复杂性.究其原因,除了生油岩类型不太理想外,后期改造强烈导致保存条件较差及所采用的技术方法不过关也是非常重要的因素.如何寻找改造弱、破坏小、保存好的构造,是下一步勘探突破的重点,而先进适用的技术方法是关键因素.