Based on the third-generation oceanic wave prediction model (WAVEWATCH Ⅲ) ,the third-generation nearshore wave calculation model (SWAN) and the mathematical tide, tidal current and cyclone current model, which have been improved, interconnected and expanded, a coupled model of offshore wave, tide and sea current under tropical cyclone surges in the South China Sea has been established. The coupled model is driven by the tropical cyclone field containing the background wind field. In order to test the hindcasting effect of the mathematical model, a comparison has been made between the calculated results and the observational results of waves of 15 cyclone cases, water levels and current velocities of the of 7 cyclones. The results of verification indicate that the calculated and observed results are basically identical. 相似文献
The Ningqiang meteorite is a fall carbonaceous chondrite, containing various Ca-, Al-rich inclusions that usually escaped from secondary events such as high-temperature heating and low- temperature alteration. However, it has not yet been classified into any known chemical group. In order to address this issue, 41 elements of the bulk Ningqiang meteorite were analyzed using inductively coupled plasma mass spectrometry （ICP-MS） and inductively coupled plasma atom emission spectrometry （ICP-AES） in this study. The Allende （CV3） carbonaceous chondrite and the Jilin （H5） ordinary chondrite were also measured as references, and our analyses are consistent with the previous results. Rare earth and other refractory lithophile elements are depleted in Ningqiang relative to both Allende and mean CK chondrites. In addition, the REE pattern of Ningqiang is nearly flat, while that of Allende shows slight enrichment of LREE relative to HREE. Siderophile elements of Ningqiang are close to those of mean CK chondrites, but lower than those of Allende. Our new analyses indicate that Ningqiang cannot be classified into any known group of carbonaceous chondrites, consistent with previous reports. 相似文献
On the basis of a one-by-one latitude-longitude grid three-dimensional seismic velocity model, the crustal P-wave velocity structure in eastern China (105-125°E and 18-41°N) is obtained, and a set of geotherms for each grid is established for P-T correction on P-wave velocities. The average depths of sub-crustal layers and their average P-wave velocities of 18 tectonic units in eastern China are exhibited. Our result presents a 32-34 km thick crust beneath eastern China, which is thinner than previous studies, with an average velocity of 6.54 km/s, corresponding to a 5 kg/m3 variation in crustal mean density. The thicker upper but thinner middle and lower crust results in a lower average seismic velocity of eastern China. An intermediate crustal composition with a SiO2 content of 59.7 wt% has been estimated. However, there exists a significant lateral variation in the crustal structures among the tectonic units of eastern China. The structure and composition features of some regions in eastern China in 相似文献
Urban agglomerations in China have become the strategic core of national economic development and the main component of the new type of urbanization. However, they are threatened by a series of eco-environmental problems and challenges, including the severe overexploitation of natural resources. Eco-efficiency, which is defined as accomplishing the greatest possible economic benefit with the least possible resource input and damage to the environment, is used as an indicator to quantify the sustainability of urban agglomerations. In this work, a traditional data envelopment analysis (DEA) model with a slack-based measurement (SBM) model of undesirable outputs, was used to assess and compare the economic efficiency and eco-efficiency of four major urban agglomerations in eastern China (UAECs) in 2005, 2011, and 2014. The spatio-temporal characteristics of the evolution of urban agglomerations were analyzed. Based on the results of a slack analysis, suggestions for improving the eco-efficiency of the four UAECs are provided. The overall economic efficiency of urban agglomerations located in the Shandong Peninsula, Yangtze River Delta, and Pearl River Delta displayed a V-shaped pattern (decreased and then increased). In contrast, the overall economic efficiency of the Beijing-Tianjin-Hebei urban agglomeration declined during the study period. The Beijing-Tianjin-Hebei urban agglomeration had a considerable loss of economic efficiency due to pollution, whereas the Shandong Peninsula urban agglomeration was less impacted. Overall, the eco-environmental efficiency of the four UAECs declined from 2005 to 2011 and then increased from 2011 to 2014. In addition, the urban eco-efficiency in the four coastal UAECs was characterized by different evolution patterns. The eco-efficiency was higher in the peri-urban areas of the core cities, riverside areas, and seaside areas and lower in the inland cities. The core cities of the Beijing-Tianjin-Hebei, Yangtze River Delta, and Pearl River Delta urban agglomerations were characterized by high resource consumption, economic benefit output, and eco-efficiency. In most of cities in the urban agglomerations, the emission of pollutants declined, leading to a reduction of pollutants and mitigation of environmental problems. In addition, a differential analysis, from the perspective of urban agglomeration, was performed, and concrete suggestions for improvement are proposed.
