Oil spill models can effectively simulate the trajectories and fate of oil slicks, which is an essential element in contingency planning and effective response strategies prepared for oil spill accidents. However, whe...Oil spill models can effectively simulate the trajectories and fate of oil slicks, which is an essential element in contingency planning and effective response strategies prepared for oil spill accidents. However, when applied to offshore areas such as the Bohai Sea, the trajectories and fate of oil slicks would be affected by time-varying factors in a regional scale, which are assumed to be constant in most of the present models. In fact, these factors in offshore regions show much more variation over time than in the deep sea, due to offshore bathymetric and climatic characteristics. In this paper, the challenge of parameterizing these offshore factors is tackled. The remote sensing data of the region are used to analyze the modification of wind-induced drift factors, and a well-suited solution is established in parameter correction mechanism for oil spill models. The novelty of the algorithm is the self-adaptive modification mechanism of the drift factors derived from the remote sensing data for the targeted sea region, in respect to empirical constants in the present models. Considering this situation, a new regional oil spill model(i4Oil Spill) for the Bohai Sea is developed, which can simulate oil transformation and fate processes by Eulerian-Lagrangian methodology. The forecasting accuracy of the proposed model is proven by the validation results in the comparison between model simulation and subsequent satellite observations on the Penglai 19-3 oil spill accident. The performance of the model parameter correction mechanism is evaluated by comparing with the real spilled oil position extracted from ASAR images.展开更多
对长江下游稻麦两熟农田生态系统2009—2010年的CH4和N2O排放以及土壤碳固定进行了分析,初步研究了秸秆还田对稻麦两熟高产农田净增温潜势的影响。结果表明,秸秆还田对稻麦两熟高产农田周年CH4和N2O排放总量、土壤碳固定量以及净增温潜...对长江下游稻麦两熟农田生态系统2009—2010年的CH4和N2O排放以及土壤碳固定进行了分析,初步研究了秸秆还田对稻麦两熟高产农田净增温潜势的影响。结果表明,秸秆还田对稻麦两熟高产农田周年CH4和N2O排放总量、土壤碳固定量以及净增温潜势均有显著或极显著影响:秸秆还田条件下周年CH4、N2O排放总量分别为394 kg CH4.hm-2、2.39 kg N2O.hm-2,土壤碳固定量、净增温潜势分别为1.14 t C·hm-2、6383 kg CO2-equivalents·hm-2;较秸秆不还田增加CH4排放总量152%、减少N2O排放总量14%、增加土壤碳固定量531%、增加净增温潜势57%。以上结果表明,秸秆还田使短期内稻麦两熟高产农田的温室效应明显提高,但其长期效果如何还有待观测。展开更多
In recent years,the exponential proliferation of smart devices with their intelligent applications poses severe challenges on conventional cellular networks.Such challenges can be potentially overcome by integrating c...In recent years,the exponential proliferation of smart devices with their intelligent applications poses severe challenges on conventional cellular networks.Such challenges can be potentially overcome by integrating communication,computing,caching,and control(i4C)technologies.In this survey,we first give a snapshot of different aspects of the i4C,comprising background,motivation,leading technological enablers,potential applications,and use cases.Next,we describe different models of communication,computing,caching,and control(4C)to lay the foundation of the integration approach.We review current stateof-the-art research efforts related to the i4C,focusing on recent trends of both conventional and artificial intelligence(AI)-based integration approaches.We also highlight the need for intelligence in resources integration.Then,we discuss the integration of sensing and communication(ISAC)and classify the integration approaches into various classes.Finally,we propose open challenges and present future research directions for beyond 5G networks,such as 6G.展开更多
This note looks at the two similarity solutions of the Navier-Stokes equations in polar coordinates. In the second solution an initial value problem is reduced into generalized stationary KDV and hence integrable.
基金supported by following programs: 1) NSFC-Shandong Joint Fund for Marine Science Research Centers (Grant No. U1406404)The National High Technology Research and Development Program of China (Grant No. 2014AA09A511)+2 种基金The Scientific and Technological Innovation Project of the Qingdao National Laboratory for Marine Science and Technology (Grant No. 2015ASKJ01)International Cooperation and Exchange of the National Natural Science Foundation of China (Grant No. 61361136001)Open Fund of Key Laboratory of Marine Spill Oil Identification and Damage Assessment Technology SOA (Grant No. 201508)
文摘Oil spill models can effectively simulate the trajectories and fate of oil slicks, which is an essential element in contingency planning and effective response strategies prepared for oil spill accidents. However, when applied to offshore areas such as the Bohai Sea, the trajectories and fate of oil slicks would be affected by time-varying factors in a regional scale, which are assumed to be constant in most of the present models. In fact, these factors in offshore regions show much more variation over time than in the deep sea, due to offshore bathymetric and climatic characteristics. In this paper, the challenge of parameterizing these offshore factors is tackled. The remote sensing data of the region are used to analyze the modification of wind-induced drift factors, and a well-suited solution is established in parameter correction mechanism for oil spill models. The novelty of the algorithm is the self-adaptive modification mechanism of the drift factors derived from the remote sensing data for the targeted sea region, in respect to empirical constants in the present models. Considering this situation, a new regional oil spill model(i4Oil Spill) for the Bohai Sea is developed, which can simulate oil transformation and fate processes by Eulerian-Lagrangian methodology. The forecasting accuracy of the proposed model is proven by the validation results in the comparison between model simulation and subsequent satellite observations on the Penglai 19-3 oil spill accident. The performance of the model parameter correction mechanism is evaluated by comparing with the real spilled oil position extracted from ASAR images.
文摘对长江下游稻麦两熟农田生态系统2009—2010年的CH4和N2O排放以及土壤碳固定进行了分析,初步研究了秸秆还田对稻麦两熟高产农田净增温潜势的影响。结果表明,秸秆还田对稻麦两熟高产农田周年CH4和N2O排放总量、土壤碳固定量以及净增温潜势均有显著或极显著影响:秸秆还田条件下周年CH4、N2O排放总量分别为394 kg CH4.hm-2、2.39 kg N2O.hm-2,土壤碳固定量、净增温潜势分别为1.14 t C·hm-2、6383 kg CO2-equivalents·hm-2;较秸秆不还田增加CH4排放总量152%、减少N2O排放总量14%、增加土壤碳固定量531%、增加净增温潜势57%。以上结果表明,秸秆还田使短期内稻麦两熟高产农田的温室效应明显提高,但其长期效果如何还有待观测。
基金supported in part by National Key R&D Program of China(2019YFE0196400)Key Research and Development Program of Shaanxi(2022KWZ09)+4 种基金National Natural Science Foundation of China(61771358,61901317,62071352)Fundamental Research Funds for the Central Universities(JB190104)Joint Education Project between China and Central-Eastern European Countries(202005)the 111 Project(B08038)。
文摘In recent years,the exponential proliferation of smart devices with their intelligent applications poses severe challenges on conventional cellular networks.Such challenges can be potentially overcome by integrating communication,computing,caching,and control(i4C)technologies.In this survey,we first give a snapshot of different aspects of the i4C,comprising background,motivation,leading technological enablers,potential applications,and use cases.Next,we describe different models of communication,computing,caching,and control(4C)to lay the foundation of the integration approach.We review current stateof-the-art research efforts related to the i4C,focusing on recent trends of both conventional and artificial intelligence(AI)-based integration approaches.We also highlight the need for intelligence in resources integration.Then,we discuss the integration of sensing and communication(ISAC)and classify the integration approaches into various classes.Finally,we propose open challenges and present future research directions for beyond 5G networks,such as 6G.
文摘This note looks at the two similarity solutions of the Navier-Stokes equations in polar coordinates. In the second solution an initial value problem is reduced into generalized stationary KDV and hence integrable.
