大城市医疗健康资源空间交互及其网络演化——以郑州中心城区为例     

冉钊  高尚  杨捷  高建华  张佰发 《地理研究》2022,41(2):494-508

认知资源要素在地表人文活动中的空间交互性对地理学研究具有重要意义。本文基于人文-经济地理学相关理论,从“单资源-复合资源-资源网络”多尺度视角出发,初步构建了医疗健康资源空间交互研究的基本理论框架,利用2012年和2020年百度地图POI数据,综合运用Ripley's K函数、格网熵指数、协同区位商以及社会网络分析等定量方法,从集聚交互、功能交互和网络交互3个方面研究郑州市医疗健康资源空间交互及其网络演化特征。结果表明：① 从集聚交互上看,各类医疗健康资源在数量和增速上扩张明显,同时呈现出显著集聚特征且集聚程度逐步增强,相对而言,更具综合性的医院健康资源的集聚程度最高;多距离下各类医疗健康资源集聚规模差异在不断缩小,集聚交互向良性方向发展。② 从功能交互上看,医疗健康资源的功能主导类型逐渐复杂,交互复合性逐步增强。医疗健康资源功能交互空间格局经历了主导类型由“单功能为主、多功能兼容”向“多功能为主、单功能为辅”转变,由点状格局到连片发展的蔓延模式与空间跳跃的飞地模式并存的转变特征。③ 从网络交互上看,医疗健康资源网络密度基本保持稳定,网络联系性质演化特征明显。诊疗与医药健康资源始终处于强联系的地位,存在集聚促进机制;理疗健康资源在关联网络中联系强度逐步提高,网络地位有所上升;而医院健康资源以其独有的规模大、高品质和综合性等特征在网络体系中具有较强独立性。  相似文献   

Extraction of Gravity–Magnetic Anomalies Associated with Pb–Zn–Fe Polymetallic Mineralization in Luziyuan Ore Field,Yunnan Province,Southwestern China     

Shang  Zhi  Chen  Yongqing  Xu  Xiaoting  Zhao  Binbin 《Natural Resources Research》2022,31(4):1963-1979

The method of bi-dimensional empirical mode decomposition (BEMD) and the combined methods of entropy weight–Technique for Order of Preference by Similarity to an Ideal Solution (TOPSIS) were used to decompose gravity–magnetic data and evaluate targets in the Luziyuan Pb–Zn–Fe polymetallic ore field and surrounding areas. Three meaningful bi-dimensional intrinsic mode function (BIMF) images were obtained by BEMD at different wavelengths, depicting different layers of geological architectures in the study area. The results are as follows. (1) The BIMF2 images depict the shallow local geological architecture and show positive gravity–magnetic anomalies of the skarn alteration and Pb–Zn–Fe mineralization distributed around concealed granites. (2) The BIMF3 images depict the medium-depth geological architecture, indicating that concealed granitic stocks, which are shallow extensions of a deeply concealed pluton, intruded along the NE-trending fault. (3) The BIMF4 images depict gravity–magnetic anomalies at greater depth, which likely reflect regional geological architectures, indicating the potential presence of a large, concealed intermediate-acid pluton in the negative anomaly zone. Three potential targets (A, B, and C) were delineated based on BEMD results of the original gravity–magnetic data. The entropy weight–TOPSIS evaluation results show that the ranking of the metallogenic potential of the delineated targets in the study area is B, A, and C, with relative proximity values of 0.4576, 0.3925, and 0.1499, respectively. The results of this study can be used to guide future exploration.

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基于快速鲁棒性主成分分析的日冕喷流自动检测方法     

耿成杰  李润鑫  刘辉  尚振宏 《天文研究与技术》2022,(1)

使用快速鲁棒性主成分分析(Fast Robust Principal Component Analysis,Fast RPCA)方法对日冕序列图像中的日冕喷流活动进行检测。检测的基本思路是利用快速鲁棒性主成分分析方法中低秩和稀疏分解的思想与日冕序列图像中有着变化尺度稍小且占比较大的随机变化背景成分、变化尺度较大且占比较小的日冕喷流的特点相结合,实现随机复杂多变的动态背景和稀疏运动目标之间的分离,从而检出作为前景变化的日冕喷流。采用太阳动力学天文台(Solar Dynamics Observatory,SDO)卫星的大气成像仪(Atmospheric Imaging Assembly,AIA)两组不同时间段、不同波段、不同观测位置的日冕序列图像作为研究对象。研究内容主要包括日冕序列图像的预处理、日冕喷流检测、快速鲁棒性主成分分析方法与帧间差分法的检测结果对比分析。实验结果表明,与帧间差分法相比,快速鲁棒性主成分分析方法能够检出强度较弱的日冕喷流,且提高了日冕喷流检测的准确度。  相似文献   

Research Status and Application Prospect of Shelf-Edge Trajectory Analysis     

Cong Fuyun  Xu Shang 《地球科学进展》2017,32(9):937-948

Trajectory analysis is the hotspot and research frontier of sedimentology and sequence stratigraphy. Compared with conventional analytical methods, trajectory analysis is aiming at identifying sedimentary systems and predicting sandstone reservoirs more directly. The definition of trajectory analysis has been made by Helland-Hansen as “The study of the lateral and vertical migration of geomorphological features and associated sedimentary environments, with emphasis on the paths and directions of migration”. Based on current research progress, the basic concepts and methods of trajectory analysis, types of basinward-migrating trajectories (ascending, flat and descending), quantitative parameters and the application in predicting deep-water sandstone reservoirs were introduced. Trajectory analysis mainly centers on two scales: Shoreline trajectories and shelf-edge trajectories. The formation of basin-floor fans has close relation with shelf-edge trajectories, and multiple case studies have confirmed that large-scale basin floor fan usually form under flat or descending shelf-edge trajectories. As research advances, trajectory analysis theory, which developed in continental margins, is believed to have been influenced by multiple factors. Thus, the accurate prediction of sandstone reservoirs requires the comprehensive consideration of the influence of sediment supply, accommodation spaces, past climate and so on. In addition, the problems and extensions of trajectory analysis were also introduced, including ①the along-strike lateral differential evolution; ② trajectory analysis theory in hydrological-closed sedimentary basins; ③the application of trajectory analysis in carbonate settings. As a developing theory, the terminology of trajectory analysis still needs standardization, and the coupling between shelf-edge trajectories and the development and distribution of deep-water sandstones also needs further understanding. The next research focus could be placed on interpreting the evolution of three-dimensional sedimentary systems, and the extension of shelf-edge trajectory theory to hydrologically-closed basin and carbonate sedimentary environments. The research methods of trajectory analysis should also follow the newest trends to allow researchers to better study the evolution of shelf-edge trajectories, for instance, integrating high-resolution seismic data and logging data, core samples, outcrops and high-resolution dating techniques to describe ancient sedimentary environment and geomorphology, combining satellite imaging, ground penetrating radar to portray the modern morphology of continental margins, and utilizing remote sensing to construct more precise three-dimensional models for outcrops.  相似文献   

The 102 Landslide: human–slope interaction in SE Tibet over a 20-year period     

Yanjun Shang  Chang-Uk Hyun  Hyeong-Dong Park  Zhifa Yang  Guangxiang Yuan 《Environmental Earth Sciences》2017,76(1):47

The evolution of large-scale landslides should be studied because, over long periods of time, primary remediation measures may suffer reduced efficiency or have to be adjusted many times. The 102 Landslide in southeast Tibet, which originally formed in 1991 with a volume of 5.1 million m³ and still exhibits post-failure activity, provides a distinctive case study. The landslide evolved from earthquake destruction and unloading, rainfall-triggered sliding, and debris flow to sands sliding slopes. The NE ringed scarp receded by 38.96 m during a five-year period (2003–2008). The total recession was 160 m with a total area of 2500 m² during a 17-year period (1991–2008). Although several types of remediation measures were applied and were temporarily effective, the normal function of the Sichuan–Tibet Highway was affected by landslide reactivation from time to time. Actual effects of the engineering measures such as retaining walls, prestressed anchor cables, and drainage ditches confirm that hasty governance of this type of large-scale landslide is generally unfeasible over long time periods. Finally, an approach involving a tunnel running backward from the front face has been adopted as a permanent solution to large-scale moraine slope failures: This engineering practice has been in progress since April 2012. This paper describes the evolution of the 102 Landslide, the engineering interventions to mitigate the effects of the landslide on the Sichuan–Tibet Highway, and the choice of tunneling as a final mitigation measure. The present study concludes that approaches that allow escape from developing geo-hazards should always be the initial choice.  相似文献   

Comparison of buried sand ridges and regressive sand ridges on the outer shelf of the East China Sea   总被引：4，自引：0，他引：4  

Ziyin Wu  Xianglong Jin  Jieqiong Zhou  Dineng Zhao  Jihong Shang  Shoujun Li  Zhenyi Cao  Yuyang Liang 《Marine Geophysical Researches》2017,38(1-2):187-198

Based on multi-beam echo soundings and high-resolution single-channel seismic profiles, linear sand ridges in U14 and U2 on the East China Sea (ECS) shelf are identified and compared in detail. Linear sand ridges in U14 are buried sand ridges, which are 90 m below the seafloor. It is presumed that these buried sand ridges belong to the transgressive systems tract (TST) formed 320–200 ka ago and that their top interface is the maximal flooding surface (MFS). Linear sand ridges in U2 are regressive sand ridges. It is presumed that these buried sand ridges belong to the TST of the last glacial maximum (LGM) and that their top interface is the MFS of the LGM. Four sub-stage sand ridges of U2 are discerned from the high-resolution single-channel seismic profile and four strikes of regressive sand ridges are distinguished from the submarine topographic map based on the multi-beam echo soundings. These multi-stage and multi-strike linear sand ridges are the response of, and evidence for, the evolution of submarine topography with respect to sea-level fluctuations since the LGM. Although the difference in the age of formation between U14 and U2 is 200 ka and their sequences are 90 m apart, the general strikes of the sand ridges are similar. This indicates that the basic configuration of tidal waves on the ECS shelf has been stable for the last 200 ka. A basic evolutionary model of the strata of the ECS shelf is proposed, in which sea-level change is the controlling factor. During the sea-level change of about 100 ka, five to six strata are developed and the sand ridges develop in the TST. A similar story of the evolution of paleo-topography on the ECS shelf has been repeated during the last 300 ka.  相似文献   

城市地下孤石的地震波场响应特征及其在地震层析成像中的应用研究     

朱智清  王道坤  汪伟民  吴殿伟  施卫力  张赛 《地质与勘探》2022,58(2):391-398

城市浅层地质条件复杂,地下孤石是常见的地质灾害体.为降低城市地下空间开发过程中孤石造成的安全隐患,本文通过构建城市地下孤石的数值模型,分析地震波在含孤石介质中的传播特征,根据地震波的传播特征利用层析成像技术对孤石进行速度成像,并通过工程实例进行验证.研究表明:(1)地震波场的数值模拟是研究地球物理勘探的有效方法,能高效...  相似文献   

世界大海洋生态系研究及其国际计划     

陈尚  朱明远  马艳 《海洋科学进展》1999,(4)

本文讨论了大海洋生态系概念和内涵的变化,介绍了全球主要大海洋生态系的分布,展示目前正在开展的大海洋生态系研究计划,重点介绍了黄海大海洋生态系的特征及其研究计划的最新动态。  相似文献   

紫彩血蛤的生物扰动对沉积物颗粒垂直分布的影响   总被引：3，自引：3，他引：0  

于子山  王诗红  张志南  周宇 《中国海洋大学学报(自然科学版)》1999,(2)

以玻璃珠作为示踪颗粒,研究底栖双壳类软体动物紫彩血蛤对沉积物的扰动。室内实验的结果表明,在整个实验周期１０ｄ内,沉积物表层的示踪颗粒有４７％向下迁移,最大迁移深度１２ｃｍ,垂直迁移率为１．８０×１０－５·ｇ－１·ｃｍ－２·ｄ－１。沉积物１０ｃｍ深处的示踪颗粒分别有４５％和１５％向上和向下迁移,向上及向下迁移率分别为１．８９×１０－５·ｇ－１·ｃｍ－２·ｄ－１和０．６３×１０－５·ｇ－１·ｃｍ－２·ｄ－１  相似文献   

钱塘江涌潮区护岸工程的设计及研究     

宣传丽  罗苑 《海洋学研究》1998,16(3):56-63

丁坝在江道整治及护岸工程中已有比较广泛的应用。丁坝的平面布置、结构型式与丁坝自身的稳定性及护岸效果密切相关。本文在对钱塘江涌潮区护岸丁坝的设计作了初步总结的基础上,指出了在丁坝结构上存在的一些问题,提出了相应的改进方案,并结合抢险修复工程,进行了现场原型试验。试验结果表明,本文提出的改进方案是切实可行的。  相似文献