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931.
932.
浮基多体系统自激运动响应的时域分析方法 总被引:2,自引:2,他引:2
浮基多体系统上部机构作业时不仅存在多体系统内部各物体间的耦合作用 ,还存在浮基与流场间的耦合作用。本文将浮基在流场中引起的辐射势表示为浮基加速度与时域规范化速度势乘积的卷积形式 ,导出流体动压力及静水系泊恢复力与浮基运动的关系。使用多刚体力学的凯恩方法得到系统的动力学方程。最后给出了在时域中数值求解系统运动响应的具体步骤 相似文献
933.
《Limnologica》2021
Monitoring programs are among the first steps to develop robust management strategies, especially in international transboundary waters. Understanding how water quality parameters are impacted by different types of land use promotes a baseline for stakeholders to define the best governance for the management of water resources. Seeking to provide this type of information, we sampled 24 streams – 12 in Brazil and 12 in Paraguay – in February, April, July, September, and November 2019. We determined water quality parameters, grouped into three categories: morphometric, physical and chemical, and nutrients. We explored differences in water quality parameters between countries, and over a one-year sampling. We also tested whether Brazilian and Paraguayan streams are impacted by agriculture, urbanization, and forest cover. Finally, we performed a partial RDA to test the influence of land use on water quality parameters and controlled spatial autocorrelation by including spatial variables (dbMEM) as a condition. Most of the water quality parameters showed significant differences between countries; only turbidity, and pH, presented significant differences between countries and sampling periods, and only water temperature varied significantly along the year. We did not find evidence that different types of land use are causing physical and chemical variance in Brazilian and Paraguayan streams (R² = 0.06, p = 0.68). In conclusion, the results evidenced that the main differences in the water quality parameters occur between countries. Based on the results, transboundary governance can use these data to implement integrated water resources management cooperation. 相似文献
934.
Jianhui Wei Ningpeng Dong Benjamin Fersch Joël Arnault Sven Wagner Patrick Laux Zhenyu Zhang Qianya Yang Chuanguo Yang Shasha Shang Lu Gao Zhongbo Yu Harald Kunstmann 《水文研究》2021,35(8):e14341
The regional terrestrial water cycle is strongly altered by human activities. Among them, reservoir regulation is a way to spatially and temporally allocate water resources in a basin for multi-purposes. However, it is still not sufficiently understood how reservoir regulation modifies the regional terrestrial- and subsequently, the atmospheric water cycle. To address this question, the representation of reservoir regulation into the terrestrial component of fully coupled regional Earth system models is required. In this study, an existing process-based reservoir network module is implemented into NOAH-HMS, that is, the terrestrial component of an atmospheric–hydrologic modelling system, namely, the WRF-HMS. It allows to quantitatively differentiate role of reservoir regulation and of groundwater feedback in a simulated ground-soil-vegetation continuum. Our study focuses on the Poyang Lake basin, where the largest freshwater lake of China and reservoirs of different sizes are located. As compared to streamflow observations, the newly extended NOAH-HMS slightly improves the streamflow and streamflow duration curves simulation for the Poyang Lake basin for the period 1979–1986. The inclusion of reservoir regulation leads to major changes in the simulated groundwater recharges and evaporation from reservoirs at local scale, but has minor effects on the simulated soil moisture and surface runoff at basin scale. The performed groundwater feedback sensitivity analysis shows that the strength of the groundwater feedback is not altered by the consideration of reservoir regulation. Furthermore, both reservoir regulation and groundwater feedback modify the partitioning of the simulated evapotranspiration, thus affecting the atmospheric water cycle in the Poyang Lake region. This finding motivates future research with our extended fully coupled atmospheric–hydrologic modelling system by the community. 相似文献
935.
以地下流体数据跟踪分析产出事件为研究对象,总结数据跟踪分析工作现状,从观测系统故障、自然环境、场地环境、人为干扰、地球物理、不明原因事件6个方面,分析2019年地下流体数据跟踪分析存在的问题,并对典型事件进行总结,为地震台站跟踪分析事件记录提供参考。 相似文献
936.
937.
东营凹陷北部陡坡带稠油成藏机理与油气运聚特征 总被引:6,自引:1,他引:5
东营凹陷北部陡坡带的王庄—宁海地区发现了大量稠油 ,但原油的成因及其成藏机理仍不甚了解 .在以往原油成因与油源调查基础上 ,利用非烃含氮化合物及包裹体均一化温度对该区进行油气运移方向与相对距离、成藏时间与期次的分析 .结果表明 ,东营凹陷北部带原油具有由南而北的运移分馏效应 ,反映北部陡坡带原油来自南部的利津洼陷 ;王庄—宁海地区原油总体具有由东而西的运移分馏效应 ,其东、西两侧各有一主要油气注气点 .王庄—宁海原油烃类与非烃组成与分布特征揭示该区油气具有混合聚集特征 .包裹体测试反映王庄—宁海地区油藏主要为晚期成藏 ,距今小于 5Ma ;而靠近生油中心地带包裹体具有早期成藏的记录 (± 36Ma) . 相似文献
938.
The Classification and Model of Coalbed Methane Reservoirs 总被引:8,自引:0,他引:8
SU Xianbo LIN Xiaoying SONG Yan ZHAO Mengjun Henan University of the Sciences Jiaozuo Henan Research Institute of Petroleum Exploration Development PetroChin Beijing 《《地质学报》英文版》2004,78(3):662-666
Coalbed methane has been explored in many basins worldwide for 30 years, and has been developed commercially in some of the basins. Many researchers have described the characteristics of coalbed methane geology and technology systematically. According to these investigations, a coalbed methane reservoir can be defined: "a coal seam that contains some coalbed methane and is isolated from other fluid units is called a coalbed methane reservoir". On the basis of anatomization, analysis, and comparison of the typical coalbed methane reservoirs, coalbed methane reservoirs can be divided into two classes: the hydrodynamic sealing coalbed methane reservoirs and the self-sealing coalbed methane reservoirs. The former can be further divided into two sub-classes: the hydrodynamic capping coalbed methane reservoirs, which can be divided into five types and the hydrodynamic driving coalbed methane reservoirs, which can be divided into three types. The latter can be divided into three types. Currently, hydrodynamic s 相似文献
939.
Spatially distributed modelling of soil erosion and sediment yield at regional scales in Spain 总被引:4,自引:0,他引:4
Joris de Vente Jean Poesen Gert Verstraeten Anton Van Rompaey Gerard Govers 《Global and Planetary Change》2008,60(3-4):393-415
Initiated by the need to quantify erosion rates and the impacts of global changes on erosion, several attempts have been made to apply erosion models at regional scales. However, these models have often been directed towards on-site soil erosion estimates, emphasising sheet and rill erosion processes, and disregarding gully erosion, channel erosion and sediment transport. These models are therefore of limited use for the assessment of sediment yield, off-site impacts of erosion, and for the development of environmental management to control these impacts at regional scale. This study analyses and compares three spatially distributed models for the prediction of soil erosion and/or sediment yield at regional scales: the WATEM-SEDEM model that is based on the empirical Revised Universal Soil Loss Equation (RUSLE) in combination with a sediment transport equation, the physics-based Pan European Soil Erosion Risk Assessment model (PESERA), and a newly developed Spatially Distributed Scoring model (SPADS). The three models were applied to 61 Spanish drainage basins and model predictions were evaluated against data on measured reservoir sedimentation rates. Global data sets on land use, climate, elevation and soil characteristics were used as model input for WATEM-SEDEM and SPADS, whereas published soil erosion estimates of PESERA at 1 km2 resolution were used directly. SPADS and WATEM-SEDEM provided best results after separate calibration for basins with a Sediment Delivery Ratio (SDR) higher than 5% and those with an SDR lower than 5%. In this way, SPADS explained 67% of variation in sediment yield, while WATEM-SEDEM explained 48% of the variation. PESERA represents a promising alternative to the use of empirical models at the regional scale as it can be applied to very diverse environments with little calibration. However, PESERA provides soil erosion rates and not sediment yield estimates. For most basins PESERA soil erosion rates vary between fifty and close to zero percent of total sediment yield. Two major factors may explain this discrepancy between modelled soil erosion rates and measured sediment yield. First, it may be that PESERA underestimates soil erosion under Mediterranean conditions, although PESERA soil erosion rates are of the same order of magnitude as erosion rates measured in erosion plot studies. Second, gully-, river channel erosion and sediment transport processes may be much more important than sheet- and rill erosion for regional scale sediment yield in these environments. These issues therefore require further attention in future model development. Although spatially lumped models provide better predictions of sediment yield at the basin scale, and while validation of the predicted spatial patterns of sources and sinks of sediment requires further research, spatially distributed models are expected to be of value to support management decisions regarding the assessment of on-site and off-site impacts of erosion at the regional scale. 相似文献
940.
东营凹陷下第三系层序地层研究与隐蔽油气藏预测 总被引:18,自引:3,他引:15
应用层序地层学理论,利用地震、测井、岩心和分析化验资料,建立了东营凹陷下第三系层序界面识别标志,把东营凹陷下第三系划分为 1个超层序组,4个超层序,10个层序,进行体系域划分,建立了东营凹陷下第三系层序地层格架。构造坡折带是指由同沉积构造长期活动引起的沉积斜坡明显突变的地带,对盆地充填的可容纳空间和沉积作用可产生重要影响。通过层序地层格架与构造坡折带的研究,建立东营凹陷层序发育模式。受构造坡折带控制的层序低位域砂体和湖侵体系域砂体,成藏条件良好,最有利于形成隐蔽油气藏。 相似文献