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51.
Do collective behaviors of the daily routine of a city's inhabitants form the periodical cycling of human activity at the city level (here termed the “city's diurnal rhythm”)? If the answer is yes, do there exist geographical patterns in the city's diurnal rhythm? Using a nationwide dataset of observed uses of location‐aware services in the largest Chinese social media platform, we first confirm the significant periodicity in city‐level human activity from the perspective of the aggregate degree of social media uses over a day. We then investigate geographical changes in the diurnal rhythm of human activity and its local variations in different parts of the city, and between weekdays and weekend days, over 340 Chinese cities. Our results show that a city's diurnal rhythm across the whole country exhibits both regular, nationally conspicuous shifts along geographical gradients and locally distinct spatiotemporal changes within the city. Our findings could provide insights into the characterization of the daily routine of city‐level human activity and its geographical patterns, and have potential for several issues in terms of planning, management, and decision‐making related to human population dynamics. 相似文献
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一种地震数据多串口采集方法 总被引:1,自引:0,他引:1
地震监测系统常常使用串口异步通讯监测数据、传输命令,但由于核心器件所带的串口数量不足,通常需要扩展串口。提出以TL16C754B为核心器件的多串口数据采集方法,包括具体的系统电路的设计方法和部分驱动的编程源代码。由于该设计具有成本低、稳定性高、低耗、抗干扰能力强、电路简单等优点,已被成功地运用于微动台阵观测仪器中。 相似文献
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AbstractBlast response of submerged pipelines has been a research focus in recent years. In this article, a three-dimensional numerical model is established to investigate dynamic response of pipelines due to underwater explosion. The u–p approximation is integrated into finite element method (FEM) to simulate pore water effect in the seabed. Numerical continuity between hydraulic pressure in the flow field and pore pressure in the marine sediment is guaranteed to realize the blast response of submerged pipelines in ocean environment. Both fluid–structure interaction (FSI) and pipeline–seabed interaction (PSI) have been considered in the proposed model simultaneously. A comprehensive parametric study is carried out after validation of the present model with test data from underground explosion and underwater explosion, respectively. The effect of embedment depth, TNT equivalent, stand-off distance, pipeline diameter, and pipeline thickness to blast response of the submerged pipelines is investigated based on numerical results. Variation of deformation patterns and stress distribution of the pipeline with various installation and structure parameters has been illustrated and discussed to facilitate engineering practice. 相似文献
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Xianrong Zhang Jianming Gong Zhilei Sun Jing Liao Bin Zhai Libo Wang Xilin Zhang Cuiling Xu Wei Geng 《海洋学报(英文版)》2021,40(9):23-32
Cold seeps are pervasive along the continental margin worldwide,and are recognized as hotspots for elemental cycling pathway on Earth.In this study,analyses of pore water geochemical compositions of one-400 cm piston core(S3) and the application of a mass balance model are conducted to assess methane-associated biogeochemical reactions and uncover the relationship of methane in shallow sediment with gas hydrate reservoir at the Makran accretionary wedge off Pakistan.The results revealed that approximately 77% of sulfate is consumed by the predominant biogeochemical process of anaerobic oxidation of methane.However,the estimated sulfate-methane interface depth is-400 cm below sea floor with the methane diffusive flux of 0.039 mol/(m~2·a),suggesting the activity of methane seepage.Based on the δ~(13)C_(DIC) mass balance model combined with the contribution proportion of different dissolved inorganic carbon sources,this study calculated the δ~(13)C of the exogenous methane to be-57.9‰,indicating that the exogenous methane may be a mixture source,including thermogenic and biogenic methane.The study of pore water geochemistry at Makran accretionary wedge off Pakistan may have considerable implications for understanding the specific details on the dynamics of methane in cold seeps and provide important evidence for the potential occurrence of subsurface gas hydrate in this area. 相似文献
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基于第三次国土调查城镇村内部细化调查的工作要求和数据基础,梳理了城镇村调查边界划定、城镇村土地利用框架构建、城镇村土地利用图斑转绘、城镇村土地利用类型判定、外业补充调查等城镇村内部细化调查环节;归纳了1:2000基础地理信息数据、不动产登记数据、基础性地理国情监测数据等已有调查成果在各调查环节的数据转换利用方式,为城镇... 相似文献
59.
区域数字地震台网实时速报系统研究 总被引:8,自引:2,他引:6
根据我国地震监测台网的发展趋势,提出了区域数字地震台网实时速报系统的发展目标,研究了实现这一目标应解决的实时数据流接收、震相自动识别、震相可靠性处理、实时地震定位、震相到时等值线实时绘制、地震震级的实时计算、地震动强度分布图的实时绘制等问题.我们编制了一套实时地震速报软件,实现了上述功能,并用福建数字地震台网记录的地震事件进行软件功能测试.测试结果表明:对于网内地震,软件处理结果基本达到中国地震局地震速报评比满分的要求,速报时间缩短至30~50 s.此外,通过实时仿真技术,系统可给出实际观测到的PGA、PGV、PGD等值线图,可以为应急救灾确定重灾区和有感范围提供帮助. 相似文献
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