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1.
地籍空间实体及其时空拓扑关系   总被引:10,自引:1,他引:9  
从地籍实体及其静态空间关系的推导出发,讨论了地籍变更的几种类型,创造性地应用地籍实体变更事件驱动地籍空间实体及其拓扑关系的变更,并把地籍变更情况下时空发生的变化归结为碎分和复合进行处理。  相似文献   
2.
Foreword     
Destructive earthquakes have caused great damage in China and the United States and collapsing buildings havecaused many deaths and injuries. The field of earthquake engineering studies earthquake hazards, the occurrence ofearthquakes of various magnitudes, the nature of the ground shaking during an earthquake, the vibration of structuresduring earthquakes, the strengthening of existing structures and the design of new structures to be earthquake resistant,and finally, how to cope with earthquake damage and restore a city to normal functioning. Such efforts are in progressin both countries, but unfortunately, the language barrier interferes with the free flow of information between China andthe Untied States. It would be mutually beneficial if some means could be developed to promote the exchangeof information across the Pacific Ocean. This new journal has been established for this purpose and its success willbe an important step in promoting earthquake engineering in China and the United States.  相似文献   
3.
区域生态环境脆弱性评价——以西藏"一江两河"地区为例   总被引:8,自引:2,他引:8  
陶和平  高攀  钟祥浩 《山地学报》2006,24(6):761-768
区域生态环境脆弱性评价是当前人类日益关心的问题之一。以西藏“一江两河”地区为例探讨区域生态环境脆弱性评价的方法和指标体系,建立了基于逆向指标测度的评价模型;同时选取1990年和2004年两个时段的数据进行分形,通过比较两个年份脆弱性评价结果可以看出自1990年“一江两河”开发区建立以来,随着区域经济活动的日益加强,区域生态环境脆弱性不断加剧,经济发展对环境的压力不断加大,区域未来持续发展受到威胁;从影响区域生态环境脆弱性因子看,1990年主要是自然因子,2004年人为因子占比重加大;从县域生态环境脆弱类型来看,自1990年以来“一江两河”地区高脆弱型县由4个增加到10个,县域经济发展越迅速,生态环境脆弱性变化越快,经济发展对区域生态环境脆弱性的影响显著。  相似文献   
4.
5.
主要讨论高斯平稳过程增量的一个结果.综合考虑高斯过程在区间[0,h]上一个线性组合后,重新改写了尾概率不等式,推广了现有结果.  相似文献   
6.
当前国内主要用钻井资料建立高频层序地层格架,地震资料应用偏少,只是选一些典型的基干剖面进行分析,这样不可避免的导致一些穿层现象。以松辽盆地南部四方坨子地区上白垩统青山口组—姚家组为解剖对象,在钻井层序划分的基础上,充分应用地震资料,通过制作合成地震记录,建立了地震与钻井相互统一的3~4级层序地层格架,共划分出四个三级层序(其中青山口组三个,姚家组一个)和20个四级层序。  相似文献   
7.
Cluster models for earthquakes: Regional comparisons   总被引:2,自引:0,他引:2  
Four clustering models are fitted by means of a spectral-likelihoodmethod to series of earthquakes in each of 14 seismic regions. It is concluded that from these models only the Neymann—Scott process, containing both short- and long-term components, is satisfactory for all regions. By inspecting the parameters of this model the consistency of results between regions of similar geological type is studied and the characteristics of different types of region are compared.  相似文献   
8.
《Sedimentology》2018,65(4):1354-1377
The widespread distribution of tidal creeks and channels that undertake meandering behaviour in modern coasts contrasts with their limited documentation in the fossil record, where point‐bar elements arising from the interaction between a mix of both fluvial and tidal currents are mainly documented. The sedimentary products of tidal channel‐bend evolution are relatively poorly known, and few studies have focused previously on specific facies models for tidal point bars present in modern settings. This study improves understanding of tidal channel meander bends through a multi‐disciplinary approach that combines analyses of historical aerial photographs, measurements of in‐channel flow velocity, high‐resolution facies analyses of sedimentary cores and three‐dimensional architectural modelling. The studied channel bend (12 to 15 m wide and 2 to 3 m deep) drains a salt marsh area located in the north‐eastern sector of the microtidal Venice Lagoon, Italy. Historical photographs show that, during the past 77 years, the bend has translated seaward ca 15 m. Results show that the channel bend formed on a non‐vegetated mud flat that was progressively colonized by vegetation. Seaward translation occurred under aggradational conditions, with an overall migration rate of 0·2 to 0·3 m year−1, and was promoted by the occurrence of cohesive, poorly erodible outer bank deposits. Ebb currents are dominant, and translation of the channel bend promotes erosion and deposition along the landward and seaward side of the bar, respectively. Tidal currents show a clear asymmetry in terms of velocity distribution, and their offset pattern provides a peculiar grain‐size distribution within the bar. During the flood stage, sand sedimentation occurs in the upper part of the bar, where the maximum flow velocity occurs. During the ebb stage, the bar experiences the secondary helical flow that accumulates sand at the toe of the bar. Lateral stacking of flood and ebb deposits has caused the formation of localized coarsening‐upward and fining‐upward sedimentary packages, respectively.  相似文献   
9.
在陆相煤系地层地震勘查中,由于地层的岩石类型不稳定,给采集和解释工作带来很大不便,大大的影响了勘查效果,为取得良好的勘查效果,提高采集效果和地震解释人员的综合解释能力是非常重要的。在此,就合理的施工设计、最佳的采集方法、高精度的资料处理和资料的综合解释等进行了分析,并较好地解决了上述问题。  相似文献   
10.
通过分析珠江三角洲与澳门经济合作的现状,从长远、整体利益出发,针对两地经济发展中的结构性弱点,认为澳门回归后,珠江三角洲与澳门应合理调整经济结构,如提高基础设施建设的配合与协调,促进工业结构的转型和升级,深化和加强第三产业合作的层次等。通过合作建立新的经济优势,进一步提高彼此在国际市场上的竞争能力,促进两地经济的新发展。  相似文献   
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