漾濞6.4级地震外廊式教学楼震害调查与分析

外廊式教学楼是中小学校典型的建筑形式。汶川地震后,外廊式教学楼震害引起大量研究人员重视。2021年5月21日21时48分,云南大理州漾濞县发生6.4级地震,本文作者详细调查了位于漾濞县的4所典型框架结构外廊式教学楼,以震害较为严重的漾濞一中和花椒园小学为例,分析了结构各部位发生破坏的原因。以震害现象为佐证,得出以下结论:由于横墙的约束,楼板沿纵向平动,各轴构件的本构关系可在同一坐标系下进行对比分析,结构破坏取决于构件沿纵向的极限位移。并在此基础上,从新的角度探讨了多层建筑的抗震能力。     

Flow directions of stream-groundwater exchange in a headwater catchment during the hydrologic year

Understanding near-stream groundwater dynamics and flow directions is important for predicting hillslope-stream connectivity, streamflow generation, and hydrologic controls of streamwater quality. To determine the drivers of groundwater flow in the stream corridor (i.e., the stream channel and the adjacent groundwater in footslopes and riparian areas), we observed the water levels of 36 wells and 7 piezometers along a headwater stream section over a period of 18 months. Groundwater dynamics during events were controlled by the initial position of the groundwater table relative to the subsurface structure. The near-stream groundwater table displayed a fast and pronounced response to precipitation events when lying in fractured bedrock with low storage capacity, and responded less frequently and in a less pronounced way when lying in upper layers with high storage capacity. Precipitation depth, intensity, regolith thickness above the fractured bedrock, and proximity to and elevation above the stream channel also had an effect on the groundwater dynamics, which varied with hydrologic conditions. Our high-frequency and spatially dense measurements highlight the competing influence of groundwater inflow from upslope locations, streamwater level and bedrock properties on the spatiotemporal dynamics of flowpaths in the stream corridor. Near-stream groundwater pointed uniformly towards the stream channel when the stream corridor was hydrologically connected to upslope groundwater. However, local interruptions of the water inflow from upslope locations caused flow reversals towards the footslopes. The direction of near-stream groundwater followed the local fractured bedrock topography during dry hydrologic conditions on a few occasions after events. The outcomes of this research contribute to a better understanding of the drivers controlling spatiotemporal changes in near-stream groundwater dynamics and flow directions in multiple wetness states of the stream corridor.     

景观连通性理论在城市土地适宜性评价与优化方法中的应用

针对传统的土地适宜性分析方法忽略景观水平生态过程的问题,本文将景观连通性理论应用于土地适宜性评价方法的不同阶段,以达到优化城市生态系统的目标。首先选择影响生物水平流动的主要要素作为评价因子,应用于长沙市望城区滨江片区,确定案例区的土地适宜性评价结果,建构城市土地景观过程阻力评价体系。通过水文连通性分析方法及分布式水文模型确定案例区的潜在雨水生态廊道,将之与土地适宜性评价结果进行加权叠加,根据评估结果,提出案例城市土地适宜性评价的优化方案。结果表明:景观连通性方法适用于传统城市土地适宜性评价方法的改进以及评价结果的优化。     

Identifying transit corridors for elephant using a long time-series

The role of corridors in mitigating the effects of landscape fragmentation on biodiversity is controversial. Recent studies have highlighted the need for new approaches in corridor design using long-term datasets. We present a method to identify transit corridors for elephant at a population scale over a large area and an extended period of time using long-term aerial surveys. We investigated environmental and anthropogenic factors directly and indirectly related to the wet versus dry season distribution of elephant and its transit corridors. Four environmental variables predicted the presence of elephant at the landscape scale in both seasons: distance from permanent water, protected areas and settlements and vegetation structure. Path analysis revealed that altitude and monthly average NDVI, and distance from temporary water had a significant indirect effect on elephant distribution at local scale in dry and wet seasons respectively. Five transit corridors connecting Tarangire National Park and the northern as well as south-eastern wet season dispersal areas were identified and matched the wildlife migration routes described in the 1960s. The corridors are stable over the decades, providing landscape connectivity for elephant. Our approach yielded insights how advanced spatial analysis can be integrated with biological data available from long-term datasets to identify actual transit corridors and predictors of species distribution.     

中哈边境地区旅游廊道空间布局与发展系统

在国家“一带一路”倡议以及国务院关于支持沿边重点地区开发开放的大背景下,新疆丰富多样的边境旅游资源迫切需要寻找可行的路径加以释放。如何围绕边境旅游主题构建旅游产业要素线性空间,将是边境旅游发展需要从空间上思考和突破的关键问题。以“点-轴”理论为基础,运用中心职能指数和引力模型的定量方法分析中哈边境地区旅游节点、旅游廊道及其旅游地发展系统,对促进边疆地区旅游产业要素自由流动,形成布局合理、功能完善、特色鲜明的目的地形象具有重要的参考价值。研究表明：中哈边疆地区一级旅游节点有5个,二级旅游节点有7个;一级廊道节点段5个,二级廊道节点段11个;四大旅游地发展系统为哈吉民族风情边境旅游系统、塔城生态休闲边境旅游系统、博温康养度假边境旅游系统和霍霍察昭文化古迹边境旅游系统。     

深港西部通道平面及高程控制网联合测量

横过后海湾的深港西部通道,是一条连接香港和深圳两地的策略性跨境道路大桥,由香港特别行政区政府和深圳市人民政府共同投资兴建。兴建大桥用的平面及高程控制网的联合测量由香港路政署和深圳市深港西部通道工程筹建办公室联合策划和完成。论文讲述两地的坐标和高程系统转换关系,汇报了建立大桥专用的独立坐标系统及连接两地高程系统的工作和成果。     

河西走廊地质记录中的新仙女木事件及其前后古地理环境演变

新仙女木事件在河西走廊地区开始于 12 5 8ka·B·P ,结束于 9 4ka·B·P ,极盛期为11 0ka·B·P左右。新仙女木事件使河西走廊地区晚更新世末转温暖湿润的气候在 12 0～ 10 0ka·B·P之间发生间断。降温期间 ,突发性洪水、干旱、风暴、沙暴、尘暴极端事件和突发性火灾频繁发生。降水减少 ,湖泊干涸 ,生态环境恶劣 ,沙漠化日益严重。古地理环境的演变 ,影响和限制了动物群的繁衍和人类文化的发展。     

河西走廊城镇地貌特征分析与开发评价

本文阐述了河西走廊城镇的地貌特征,从建设开发的角度分析评价城镇地貌特征并提出了今后合理发展的方向与对策。     

河西地区水、土资源的合理开发利用

通过调查计算,评述了河西地区水、土资源状况及开发利用过程中引起的环境变化和存在的主要问题,提出合理开发利用水、土资源的建议和意见:1.以流域为单元进行水、土资源合理利用布局,2.以水定地、搞好水土平衡,3.提高单位面积产量,适当扩大灌溉面积,4.合理利用和改良草场,5.种草种树,保护植被,6.提高水资源利用率。     

珠江三角洲经济区东部新兴的惠淡澳经济走廊

本文分析惠淡澳经济走廊的区域条件、历史背景及其形成、发展和前景，探讨其对实施建设珠江三角洲经济区战略决策的意义。