[Objective] This study aimed to conduct correspondence cluster analysis of the trace elements in Chinese wolfberry from Qinghai and Ningxia regions, and to investigate the relationship among the quality of the wolfber...[Objective] This study aimed to conduct correspondence cluster analysis of the trace elements in Chinese wolfberry from Qinghai and Ningxia regions, and to investigate the relationship among the quality of the wolfberry samples, the composition of trace elements and the sample sources. [Method] The determined contents of trace elements and ratios of zinc to copper (Zn/Cu) of wolfberry from 11 different producing areas of Qinghai and Ningxia regions were adopted to construct the raw measurement data matrix, to analyze the distribution characteristics of the trace ele- ments in wolfberry from Qinghai and Ningxia by using the corresponding cluster analysis method. [Result] The quality of wolfberry samples in 7hongning County, Zhongwei City, Pingluo County, Shizuishan City, Heicheng Town of Ningxia Hui Au-tonomous Region and Hehuang Valley, Golmud City of Qinghai Province is mainly related to the contents of Zn and Mn; Zn/Cu greatly affects the quality of Chinese wolfberry in Dulan County of Qinghai Province; Fe has great effect on the quality of Chinese wolfberry in Yinchuan City of Ningxia Hui Autonomous Region; Cu greatly affects the quality of Chinese wolfberry in Nuomuhong Village of Qinghai Province and a wolfberry research institute in Ningxia. [Conclusion] The relationship between the quality of wolfberry from different producing areas and the trace elements was investigated, which provides theoretical and practical basis for the cultivation, har- vesting, processing, and further development and utilization of Chinese wolfberry resources from different producing areas.展开更多
The role of retailing has diminished in the center of cities of Western countries since its heyday in the 1920s. This trend was caused by violent transformations in the economic, social and locational contexts which i...The role of retailing has diminished in the center of cities of Western countries since its heyday in the 1920s. This trend was caused by violent transformations in the economic, social and locational contexts which involve resi- dential suburbanization, as well as new forms of commercial development out of town. As far as transforming China is concerned, the downtown retailing center has also come to turning point of development in the context of suburbaniza- tion. Based on the survey of Beijing residents’ shopping behavior, the present research tends to making clear the actual change and development problem of downtown retailing center. Combining with the macro retailing environment, re- lated influencing factors are further discussed too. Study results show that downtown retailing still plays an important part in resident’s shopping activity. However, with rapid urban sprawl, retailing in urban center has been greatly threatened by booming out-of-town commerce. In the course of such spatial change, the suburbanization of resident, the prevalence of new commercial forms and the change of consumers’ life style all have exerted their own pressure on downtown retailing. But for the special socioeconomic background of development and the support of government policy, it will still keep its vitality of retailing for a long period of time.展开更多
We investigated the effect of tree cover,forest patch and disturbances on tree species richness in a highly diverse conservation area of northeast Bangladesh.A systematic sampling protocol was adopted and 80 sub-plots...We investigated the effect of tree cover,forest patch and disturbances on tree species richness in a highly diverse conservation area of northeast Bangladesh.A systematic sampling protocol was adopted and 80 sub-plots from twenty five 1 ha plots were used for the vegetation survey.Linear regression analysis was performed to understand the effect of patch area,disturbances and tree cover on tree species richness.Ordination using Redundancy analysis(RDA) and Non-metric Multi Dimensional Scaling(NMDS) were also performed to explore the tree species compositional similarities along the stand characteristics gradient and locations of the sample plots.Our study revealed that,forest patch size has greater influence on species richness.Areas with medium level of disturbances have shown greater species richness.In constrained ordination the selected explanatory variables regulated the richness of common species.Our findings can be useful for better forest management and restoration of landscapes of conservation needs using ecologically important species.展开更多
With today's economic globalization,inter-provincial trade plays an important role in a country's economy.This paper is the first to adopt the input-output tables of 30 Chinese provinces and to summarize the e...With today's economic globalization,inter-provincial trade plays an important role in a country's economy.This paper is the first to adopt the input-output tables of 30 Chinese provinces and to summarize the evolution of China's inter-provincial trade from1987 to 2007.This paper reaches the following conclusions.First,China's inter-provincial trade has sustained a period of rapid growth.In 2007,the total volume of inter-provincial trade was twice the amount of international trade,with the eastern region accounting for the majority of the inter-provincial trade volume.GDP may have a greater effect on interprovincial trade than geographic distance does.Second,inter-provincial trade maintains a high level of concentration and overlaps with the high concentration of GDP.Third,the inter-provincial trade dependence of Chinese provinces tends to increase,an indication of the growing domestic market integration.Moreover,the eastern region's dependence on inter-provincial trade is higher than the central and western regions'.Fourth,the share of inter-provincial trade in the overall external trade of Chinese provinces has a declining tendency,which indicates a slower process of China's domestic market integration compared with international market integration.However,in terms of proportion,the external trade of most Chinese provinces is still dominated by inter-provincial trade.Fifth,most provinces with longstanding inter-provincial trade deficits are in the central and western regions.展开更多
Using 12 years of data from the Tropical Rainfall Measuring Mission(TRMM)-based Precipitation Radar(PR),spatial and diurnal variations of deep convective systems(DCSs)over the Asian monsoon region are analyzed.The DCS...Using 12 years of data from the Tropical Rainfall Measuring Mission(TRMM)-based Precipitation Radar(PR),spatial and diurnal variations of deep convective systems(DCSs)over the Asian monsoon region are analyzed.The DCSs are defined by a 20 dBZ echo top extending 14 km.The spatial distribution of DCSs genesis is also discussed,with reference to the National Centers for Environmental Prediction(NCEP)reanalysis data.The results show that DCSs occur mainly over land.They concentrate in south of 20°N during the pre-monsoon season,and then move distinctly to mid-latitude regions,with the most active region on the south slope of the Himalayas during monsoon season.DCSs over the Tibetan Plateau are more frequent than those in central-eastern China,but smaller in horizontal scale and weaker in convective intensity.DCSs in central-eastern China have more robust updrafts and generate more lightning flashes than in other Asian monsoon regions.The horizontal scale of DCSs over the ocean is larger than that over the other regions,and the corresponding minimum infrared(IR)brightness temperature is lower,whereas the convective intensity is weaker.Continental DCSs are more common from noon through midnight,and DCSs over the Tibetan Plateau are more frequently from noon through evening.Oceanic DCSs frequency has a weaker diurnal cycle with dawn maximum,and diurnal variation of DCSs over the tropical maritime continent is consistent with that over the continent.展开更多
Previous studies on modulation instabilities(MIs) in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fib...Previous studies on modulation instabilities(MIs) in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fibers with the emphasis on investigating the effects of ellipticity angle(0? ≤θ≤ 90?). Both symmetric and antisymmetric CW states are considered. In the anomalous dispersion regime, for the symmetric(antisymmetric) CW states, we show that MI gain increases dramatically(reduces first and then enhances greatly) as the increment of θ. In the normal dispersion regime, for the both CW states, the distinctive feature is that the gain of the MI bands reduces first, vanishes at θ = 45?,reappears across this ellipticity angle, and quickly increases after then.展开更多
文摘[Objective] This study aimed to conduct correspondence cluster analysis of the trace elements in Chinese wolfberry from Qinghai and Ningxia regions, and to investigate the relationship among the quality of the wolfberry samples, the composition of trace elements and the sample sources. [Method] The determined contents of trace elements and ratios of zinc to copper (Zn/Cu) of wolfberry from 11 different producing areas of Qinghai and Ningxia regions were adopted to construct the raw measurement data matrix, to analyze the distribution characteristics of the trace ele- ments in wolfberry from Qinghai and Ningxia by using the corresponding cluster analysis method. [Result] The quality of wolfberry samples in 7hongning County, Zhongwei City, Pingluo County, Shizuishan City, Heicheng Town of Ningxia Hui Au-tonomous Region and Hehuang Valley, Golmud City of Qinghai Province is mainly related to the contents of Zn and Mn; Zn/Cu greatly affects the quality of Chinese wolfberry in Dulan County of Qinghai Province; Fe has great effect on the quality of Chinese wolfberry in Yinchuan City of Ningxia Hui Autonomous Region; Cu greatly affects the quality of Chinese wolfberry in Nuomuhong Village of Qinghai Province and a wolfberry research institute in Ningxia. [Conclusion] The relationship between the quality of wolfberry from different producing areas and the trace elements was investigated, which provides theoretical and practical basis for the cultivation, har- vesting, processing, and further development and utilization of Chinese wolfberry resources from different producing areas.
基金Under the auspices of the National Natural Science Foundation of China (No. 40171034)
文摘The role of retailing has diminished in the center of cities of Western countries since its heyday in the 1920s. This trend was caused by violent transformations in the economic, social and locational contexts which involve resi- dential suburbanization, as well as new forms of commercial development out of town. As far as transforming China is concerned, the downtown retailing center has also come to turning point of development in the context of suburbaniza- tion. Based on the survey of Beijing residents’ shopping behavior, the present research tends to making clear the actual change and development problem of downtown retailing center. Combining with the macro retailing environment, re- lated influencing factors are further discussed too. Study results show that downtown retailing still plays an important part in resident’s shopping activity. However, with rapid urban sprawl, retailing in urban center has been greatly threatened by booming out-of-town commerce. In the course of such spatial change, the suburbanization of resident, the prevalence of new commercial forms and the change of consumers’ life style all have exerted their own pressure on downtown retailing. But for the special socioeconomic background of development and the support of government policy, it will still keep its vitality of retailing for a long period of time.
基金supported by the Department of Forestry and Environment Science,Shahjalal University of Science and Technology,Bangladeshsupported by a grant from University Research Center,Shahjalal University of Science and Technology to accomplish the field work for this study
文摘We investigated the effect of tree cover,forest patch and disturbances on tree species richness in a highly diverse conservation area of northeast Bangladesh.A systematic sampling protocol was adopted and 80 sub-plots from twenty five 1 ha plots were used for the vegetation survey.Linear regression analysis was performed to understand the effect of patch area,disturbances and tree cover on tree species richness.Ordination using Redundancy analysis(RDA) and Non-metric Multi Dimensional Scaling(NMDS) were also performed to explore the tree species compositional similarities along the stand characteristics gradient and locations of the sample plots.Our study revealed that,forest patch size has greater influence on species richness.Areas with medium level of disturbances have shown greater species richness.In constrained ordination the selected explanatory variables regulated the richness of common species.Our findings can be useful for better forest management and restoration of landscapes of conservation needs using ecologically important species.
基金National Social Science Foundation for the Youth Scholars of China:The Internal Origins of Chinese External Imbalances(Grant No.12 CJL055)Educational Development Foundation of Department of International Economic and Trade,Xiamen University:Research on the Effect of Outsourcing on China's Economy(Grant No.201112111)Humanities and Social Science Project for the Youth Scholars of the Ministry of Education:Research on China's Current Account Adjustment Mode Under the Public Finance(Grant No.11YJC790281)
文摘With today's economic globalization,inter-provincial trade plays an important role in a country's economy.This paper is the first to adopt the input-output tables of 30 Chinese provinces and to summarize the evolution of China's inter-provincial trade from1987 to 2007.This paper reaches the following conclusions.First,China's inter-provincial trade has sustained a period of rapid growth.In 2007,the total volume of inter-provincial trade was twice the amount of international trade,with the eastern region accounting for the majority of the inter-provincial trade volume.GDP may have a greater effect on interprovincial trade than geographic distance does.Second,inter-provincial trade maintains a high level of concentration and overlaps with the high concentration of GDP.Third,the inter-provincial trade dependence of Chinese provinces tends to increase,an indication of the growing domestic market integration.Moreover,the eastern region's dependence on inter-provincial trade is higher than the central and western regions'.Fourth,the share of inter-provincial trade in the overall external trade of Chinese provinces has a declining tendency,which indicates a slower process of China's domestic market integration compared with international market integration.However,in terms of proportion,the external trade of most Chinese provinces is still dominated by inter-provincial trade.Fifth,most provinces with longstanding inter-provincial trade deficits are in the central and western regions.
基金supported jointly by the National Basic Research Program of China(Grant No.2010CB428601)the National Natural Science Foundation of China(Grant Nos. 40930949&40905008)
文摘Using 12 years of data from the Tropical Rainfall Measuring Mission(TRMM)-based Precipitation Radar(PR),spatial and diurnal variations of deep convective systems(DCSs)over the Asian monsoon region are analyzed.The DCSs are defined by a 20 dBZ echo top extending 14 km.The spatial distribution of DCSs genesis is also discussed,with reference to the National Centers for Environmental Prediction(NCEP)reanalysis data.The results show that DCSs occur mainly over land.They concentrate in south of 20°N during the pre-monsoon season,and then move distinctly to mid-latitude regions,with the most active region on the south slope of the Himalayas during monsoon season.DCSs over the Tibetan Plateau are more frequent than those in central-eastern China,but smaller in horizontal scale and weaker in convective intensity.DCSs in central-eastern China have more robust updrafts and generate more lightning flashes than in other Asian monsoon regions.The horizontal scale of DCSs over the ocean is larger than that over the other regions,and the corresponding minimum infrared(IR)brightness temperature is lower,whereas the convective intensity is weaker.Continental DCSs are more common from noon through midnight,and DCSs over the Tibetan Plateau are more frequently from noon through evening.Oceanic DCSs frequency has a weaker diurnal cycle with dawn maximum,and diurnal variation of DCSs over the tropical maritime continent is consistent with that over the continent.
基金Supported by the National Natural Science Foundation of China under Grant Nos.11447113 and 11305031 Natural Science Foundation of Jiangsu Provincial Universities under Grant No.14KJB140009 the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology under Grant No.2241131301064
文摘Previous studies on modulation instabilities(MIs) in birefringent optical fibers focus on the ordinary linearly and circularly ones. This paper reports an analysis of MIs in the general elliptically birefringent fibers with the emphasis on investigating the effects of ellipticity angle(0? ≤θ≤ 90?). Both symmetric and antisymmetric CW states are considered. In the anomalous dispersion regime, for the symmetric(antisymmetric) CW states, we show that MI gain increases dramatically(reduces first and then enhances greatly) as the increment of θ. In the normal dispersion regime, for the both CW states, the distinctive feature is that the gain of the MI bands reduces first, vanishes at θ = 45?,reappears across this ellipticity angle, and quickly increases after then.