Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles an...Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles and horizontal distributions of chemical and hydrographic variables. Results show that the coastal upwelling was year-round, but the areas and intensities of the upwelling were quite different in season. The coastal upwelling occurred in all of the coastal areas of the region in spring and summer, but in autumn only in the area off Zhejiang Province, and in winter in the area off Fujian Prov- ince. It was the strongest in summer and the weakest in winter. Geographically, it was the strongest in the area off Zhejiang Province and the weakest in the southmost or northmost parts of the East China Sea. The estimated nutrient fluxes upward into euphotic zone through coastal upwelling were quite large, es- pecially for phosphate, which contributed significantly to primary production and improved the nutrient structure of the coastal ecosystem in the East China Sea.展开更多
The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This proble...The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.展开更多
The influences due to several AVIs （airfoil-vortex interactions） are studied by using a two-dimensional CFD （computational fluid dynamics） method. The primary goal of this effort is to assess the variation of vort...The influences due to several AVIs （airfoil-vortex interactions） are studied by using a two-dimensional CFD （computational fluid dynamics） method. The primary goal of this effort is to assess the variation of vortex center location and vortex circulation associated with sequential AVI toward an improvement of the hybrid method of CFD and prescribed wake model, which closely relates to predicting the BVI （blade-vortex interaction） noise radiated from a helicopter rotor. The representative of sequential AVI is performed by single vortex and two airfoils. Investigations with respect to vortex center location and vortex circulation after AVIs have been made by varying the miss-distance, which is the vertical distance between the airfoil leading edge and the vortex center. Correlations between miss-distance and vorticity field show that there exists complicated vortex wake flow with several vortices newly induced in 1st AVI. The pressure fluctuation amplitude clarifies that the intensity in 2nd AV1 is significantly low compared to the intensity in 1st AVI due to the influence of vortex dissipation. Simulations turned out to modify the vortex center location represented by the hybrid method using an offset value for a streamwise direction and to dissipate the vortex circulation for improving the accuracy of BVI noise prediction.展开更多
The harmonious relationship among East Asian countries has a very long history. However, it has faced serious challenges in the past hundred years. In these eventful years for our nation, Chinese literature, like the ...The harmonious relationship among East Asian countries has a very long history. However, it has faced serious challenges in the past hundred years. In these eventful years for our nation, Chinese literature, like the Chinese people, has endured hardships and pondered ways of extricating the country from its malaise. In addition to being concerned over China＇s enlightenment, salvation, independence and rejuvenation, writers have also paid considerable attention to important international forces that had a strong influence on their country＇s fate. Concern over and understanding of the Korean nation bad a particular emotional charge and relevance to their own fate. Over the course of a century, Chinese literature＇s awareness of Korea went through four stages. In the first, Korea＇s loss of independence served as a mirror of China＇s own dangerous position, menaced on all sides; in the second, the Korean people were seen as comrades-in-arms combating foreign foes; in the third, when the Korean Peninsula was divided, North Koreans continued to be regarded as comrades-in-arms while South Korea was not acknowledged; and in the final stage, amidst the interaction between ＂China style＂ and the ＂Korean wave,＂ Chinese literature＇s awareness of Korea expanded through a penetrating appreciation of Korean history involving deep ties of courage and uprightness.展开更多
基金Supported by the National Basic Research Program of China (973 Pro-gram), No. 2001CB4097
文摘Based on the field data obtained during cruises on the shelf of the East China Sea from 1997 to 1999, seasonal variations of coastal upwelling on the inner shelf are discussed by using cross-shelf transect profiles and horizontal distributions of chemical and hydrographic variables. Results show that the coastal upwelling was year-round, but the areas and intensities of the upwelling were quite different in season. The coastal upwelling occurred in all of the coastal areas of the region in spring and summer, but in autumn only in the area off Zhejiang Province, and in winter in the area off Fujian Prov- ince. It was the strongest in summer and the weakest in winter. Geographically, it was the strongest in the area off Zhejiang Province and the weakest in the southmost or northmost parts of the East China Sea. The estimated nutrient fluxes upward into euphotic zone through coastal upwelling were quite large, es- pecially for phosphate, which contributed significantly to primary production and improved the nutrient structure of the coastal ecosystem in the East China Sea.
文摘The peer-to-peer（P2P） file-sharing network as a vehicle of disseminating files has become very popular. The appearance of dozens of kinds of passive worms on this network has, however, made it unsecured. This problem has been paid attention and a few of models for passive worm propagation has been presented. Unfortunately, the dynamic properties of this network are ignored in these models. Given the fact, the characteristics of both this network and the passive worm are identified, and on this basis a new mathematical model of passive worm propagation on the P2P network is presented in applying epidemiology in this paper. Note that the dynamic properties of this network are considered in the presented model. The model has been validated by large scale simulation experiments, which demonstrates that the presented model may be used for analyzing the behaviors of passive worms and predicting the trend of their propagation.
文摘The influences due to several AVIs （airfoil-vortex interactions） are studied by using a two-dimensional CFD （computational fluid dynamics） method. The primary goal of this effort is to assess the variation of vortex center location and vortex circulation associated with sequential AVI toward an improvement of the hybrid method of CFD and prescribed wake model, which closely relates to predicting the BVI （blade-vortex interaction） noise radiated from a helicopter rotor. The representative of sequential AVI is performed by single vortex and two airfoils. Investigations with respect to vortex center location and vortex circulation after AVIs have been made by varying the miss-distance, which is the vertical distance between the airfoil leading edge and the vortex center. Correlations between miss-distance and vorticity field show that there exists complicated vortex wake flow with several vortices newly induced in 1st AVI. The pressure fluctuation amplitude clarifies that the intensity in 2nd AV1 is significantly low compared to the intensity in 1st AVI due to the influence of vortex dissipation. Simulations turned out to modify the vortex center location represented by the hybrid method using an offset value for a streamwise direction and to dissipate the vortex circulation for improving the accuracy of BVI noise prediction.
文摘The harmonious relationship among East Asian countries has a very long history. However, it has faced serious challenges in the past hundred years. In these eventful years for our nation, Chinese literature, like the Chinese people, has endured hardships and pondered ways of extricating the country from its malaise. In addition to being concerned over China＇s enlightenment, salvation, independence and rejuvenation, writers have also paid considerable attention to important international forces that had a strong influence on their country＇s fate. Concern over and understanding of the Korean nation bad a particular emotional charge and relevance to their own fate. Over the course of a century, Chinese literature＇s awareness of Korea went through four stages. In the first, Korea＇s loss of independence served as a mirror of China＇s own dangerous position, menaced on all sides; in the second, the Korean people were seen as comrades-in-arms combating foreign foes; in the third, when the Korean Peninsula was divided, North Koreans continued to be regarded as comrades-in-arms while South Korea was not acknowledged; and in the final stage, amidst the interaction between ＂China style＂ and the ＂Korean wave,＂ Chinese literature＇s awareness of Korea expanded through a penetrating appreciation of Korean history involving deep ties of courage and uprightness.
