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基于多声源波速结构成像的岩体异常区域超前辨识方法 被引量:2
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作者 董陇军 裴重伟 +2 位作者 谢鑫 张义涵 闫先航 《Engineering》 SCIE EI CAS CSCD 2023年第3期191-200,共10页
异常区域超前辨识对于预防地下岩土工程灾害具有重要作用。为了满足地下工程高精度探测的需求,本文提出一种层析成像方法以辨识复杂岩体结构中的异常区域,结合了走时层析、阻尼最小二乘和高斯滤波等技术。该方法克服了空洞区域辨识中速... 异常区域超前辨识对于预防地下岩土工程灾害具有重要作用。为了满足地下工程高精度探测的需求,本文提出一种层析成像方法以辨识复杂岩体结构中的异常区域,结合了走时层析、阻尼最小二乘和高斯滤波等技术。该方法克服了空洞区域辨识中速度差限制,减轻了迭代中孤立速度突变所带来的影响。我们开展了数值和室内实验量化评估最短路径法(Shortest-Path Method,SPM)、动态最短路径法(Dynamic Shortest-Path Method,DSPM)和快速扫描法(Fast Sweeping Method,FSM)等正演模拟的识别精度和计算效率。结果表明,在数值和室内实验中DSPM和FSM均能清晰地辨识出异常区域。陕西震奥矿山现场应用结果证明了该方法可利用矿山开采中爆破、微震等多类声源对矿山内部未知结构进行波速场成像。本研究不仅实现了走时层析成像方法在异常区域识别中的应用,而且为地下岩土工程中潜在风险源的探测提供了新的思路。 展开更多
关键词 Underground engineering Traveltime tomography Complex structures Abnormal region identification Ray tracing
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Characterization of Drought and Its Assessment over Sindh,Pakistan During 1951-2010 被引量:3
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作者 Shahzada ADNAN Kalim ULLAH 高守亭 《Journal of Meteorological Research》 SCIE CSCD 2015年第5期837-857,共21页
Drought is one of the complex meteorological disasters affecting water resources, agriculture, livestock, and socioeconomic patterns of a region. Although drought prediction is difficult, it can be monitored based on ... Drought is one of the complex meteorological disasters affecting water resources, agriculture, livestock, and socioeconomic patterns of a region. Although drought prediction is difficult, it can be monitored based on climatological information. In this study, we provide high spatiotemporal resolution drought climatology, using observational, gridded precipitation data (0.5°×0.5°) from the Global Precipitation Climatological Center and soil moisture data from the Climate Prediction Center for the 60-yr period 1951-2010. The standardized precipitation index (SPI) based on a fitted Gamma distribution and Run method has been calculated from the regional drought identification model (ReDIM) for 3, 6, 9, 12, and 24 months. The results show strong temporal correlations among anomalies of precipitation, soil moisture, and SPI. Analysis of long-term precipitation data reveals that the drought vulnerability concentrates on monsoon season (July- September), which contributes 72.4% and 82.1% of the annual precipitation in northern and southern Sindh, respectively. Annual and seasonal analyses show no significant changes in the observed precipitation. The category classification criteria are defined to monitor/forecast drought in the selected area. Further analysis identifies two longest episodes of drought, i.e., 1972 1974 and 2000 2002, while 1969, 1974, 1987, and 2002 are found to be the most severe historical drought years. A drought hazard map of Sindh was developed, in which 10 districts are recognized as highly vulnerable to drought. This study helps to explain the time, duration, intensity, and frequency of meteorological droughts over Sindh as well as its neighboring regions, and provides useful information to disaster management agencies and forecasters for assessing both the regional vulnerabilitv of drought and its seasonal predictability in Pakistan. 展开更多
关键词 CLIMATOLOGY DROUGHT standardized precipitation index (SPI) regional drought identification model (ReDIM) SINDH
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博台线--中国区域发展均衡线的重要功能与建设构想 被引量:2
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作者 方创琳 《Journal of Geographical Sciences》 SCIE CSCD 2021年第6期839-858,共20页
Promoting regional coordinated development strategy is one of the important strategies in the new period of China.Faced with the reality of unbalanced and insufficient regional development in China,it is objectively n... Promoting regional coordinated development strategy is one of the important strategies in the new period of China.Faced with the reality of unbalanced and insufficient regional development in China,it is objectively necessary to construct one or more main axes supporting the coordinated and balanced development of regions to become the identification line representing the pattern of coordinated regional development.The results show that the Bo-Tai line,the northwest-southeast axis connecting Bole of Xinjiang and Taipei of Taiwan,can be built into national development backbone line and regional balanced development line,just perpendicular to Hu Line.In 2016,the area of southwest half and northeast half of Bo-Tai Line accounts for 60%:40%,while the population accounts for 45%:55%,the economic aggregate accounts for 40%:60%,the per capita GDP ratio accounts for 44%:56%,the population density ratio accounts for 38%:62%,the economic density ratio accounts for 32%:68%,and the urbanization level ratio accounts for 48%:52%.The main average indicators are gradually tending to balanced development pattern.Further analysis shows that Bo-Tai Line is a strategic shoulder pole connecting two core zones of"the Belt and Road",and is the peaceful reunification line of China's national tranquility and Taiwan's return.Bo-Tai Line is also a solid line supported and connected by comprehensive transportation channels and a Pipa type symmetrical line for the development of cities and urban agglomerations.It is the backbone of the two-way opening up and the linkage development line between land and sea.It is also an important dividing line that promotes the coordinated development of the eastern,central and western regions,and addresses the imbalance and inadequacy of regional development.Bo-Tai Line plays an irreplaceable strategic role in promoting the coordinated and balanced regional development.It is suggested that the construction of Bo-Tai Line should be included in the national development strategy,and the development strategic plan of Bo-Tai Line should be formulated to fully release the multiple potential functions.We should build three strategic support points:the northwest endpoint,the central strategic node and the southeast endpoint;carry out a comprehensive scientific investigation of the Bo-Tai Line,and strengthen the scientific cognition and publicity;promote China's development in a higherlevel,higher-quality,more coordinated,safer and more civilized direction.Let Chinese know about the Bo-Tai Line,let the world know about the Bo-Tai Line,and let the Bo-Tai Line truly become the backbone of the great rejuvenation of the Chinese nation. 展开更多
关键词 Bo-Tai Line identification line for regional balanced development Hu Huanyong Line important function construction conception
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