Two aspects of a new method,which can be used for seismic zoning,are introduced in this paper.On the one hand,the approach to estimate b value and annual activity rate proposed by Kijko and Sellevoll needs to use the ...Two aspects of a new method,which can be used for seismic zoning,are introduced in this paper.On the one hand,the approach to estimate b value and annual activity rate proposed by Kijko and Sellevoll needs to use the earthquake catalogue.The existing earthquake catalogue contains both historical and recent instrumental data sets and it is inadequate to use only one part.Combining the large number of historical events with recent complete records and taking the magnitude uncertainty into account,Kijko’s method gives the maximum likelihood estimation of b value and annual activity rate,which might be more realistic.On the other hand,this method considers the source zone boundary uncertainty in seismic hazard analysis,which means the earthquake activity rate across a boundary of a source zone changes smoothly instead of abruptly and avoids too large a gradient in the calculated results.展开更多
To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three a...To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three approaches to interpolate meteorological variables during the growing season(i.e.,May-September) were compared in Heilongjiang Province,China.Optimized meteorological variable interpolation results were then combined with stand and individual tree variables,based on data from 56 sample plots and 2886 sample trees from Korean pine plantations in two regions of the province to develop an individualtree diameter growth model(Model I) and an individualtree diameter growth model with meteorological variables(Model Ⅱ) using a stepwise regression method.Moreover,an individual-tree diameter growth model with regional effects(Model Ⅲ) was developed using dummy variables in the regression,and the significance of introducing these dummy variables was verified with an F-test statistical analysis.The models were validated using an independent data set,and the predictive performance of the three models was assessed via the adjusted coefficient of determination(R_(a)^(2)) and root mean square error(RMSE).The results suggest that the growth increment in tree diameter of Korean pine plantations was significantly correlated with the natural logarithm of initial diameter(ln D),stand basal area(BAS),logarithmic deformation of the stand density index(ln SDI),ratio of basal area of trees larger than the subject tree to their initial diameter at breast height(DBH)(BAL/D),and the maximum growingseason precipitation(Pgmax).The individual-tree diameter growth models of Korean pine plantations developed in this study will provide a good basis for estimating and predicting growth increments of Korean pine forests over larger areas.展开更多
A total of 128 Simao pine trees (Pinus kesiya var. langbianensis) from three regions of Pu'er City, Yunnan Province, People's Republic of China, were destructively sampled to obtain tree aboveground biomass (AGB...A total of 128 Simao pine trees (Pinus kesiya var. langbianensis) from three regions of Pu'er City, Yunnan Province, People's Republic of China, were destructively sampled to obtain tree aboveground biomass (AGB). Tree variables such as diameter at breast height and total height, and topographical factors such as altitude, aspect of slope, and degree of slope were recorded. We considered the region and site quality classes as the ran- dom-effects, and the topographic variables as the fixed- effects. We fitted a total of eight models as follows: least- squares nonlinear models (BM), least-squares nonlinear models with the topographic factors (BMT), nonlinear mixed-effects models with region as single random-effects (NLME-RE), nonlinear mixed-effects models with site as single random-effects (NLME-SE), nonlinear mixed-ef- fects models with the two-level nested region and site random-effects (TLNLME), NLME-RE with the fixed-ef- fects of topographic factors (NLMET-RE), NLME-SE with the fixed-effects of topographic factors (NLMET-SE), and TLNLME with the fixed-effects of topographic factors (TLNLMET). The eight models were compared by modelfitting and prediction statistics. The results showed: model fitting was improved by considering random-effects of region or site, or both. The models with the fixed-effects of topographic factors had better model fitting. According to AIC and BIC, the model fitting was ranked as TLNLME 〉 NLMET-RE 〉 NLME-RE.〉 NLMET-SE 〉 TLNLMET 〉 NLME-SE 〉 BMT 〉 BM. The differences among these models for model prediction were small. The model pre- diction was ranked as TLNLME 〉 NLME-RE 〉 NLME- SE 〉 NLMET-RE 〉 NLMET-SE 〉 TLNLMET 〉 BMT 〉 BM. However, all eight models had relatively high prediction precision (〉90 %). Thus, the best model should be chosen based on the available data when using the model to predict individual tree AGB.展开更多
This paper summarizes the negative effects on geological environment caused by groundwater exploitation and its distribution. There are seven main types of the geological environment negative effects, which are genera...This paper summarizes the negative effects on geological environment caused by groundwater exploitation and its distribution. There are seven main types of the geological environment negative effects, which are generally as follows:(1) Constant decrease of groundwater level is mainly distributed in China(East Asia), India(South Asia), Tajikistan(Central Asia) and Saudi Arabia(West Asia);(2) land subsidence occurs mainly in eastern plains of East Asia and west Siberian Plain of North Asia;(3) seawater intrusion occurs mainly in China, Japan and South Korea in East Asia, Philippines and Indonesia in Southeast Asia, the Indian coastal areas in South Asia;(4) groundwater level decline caused by groundwater exploitation in oil fields;(5) mining collapse is mainly in 50° to 70° north latitude band;(6) the total area of karst collapse in China of East Asia is as much as 197.05 km^2; and(7) ground fracture is mainly distributed in the North China Plain, Fenwei Plain and the Yangtze River Delta. Asia can be divided into 6 zones in terms of the geological environment negative effect caused by groundwater exploitation. According to analysis, with the increasing intensity of human activities, geological environment issues become more and more serious, therefore it is vital to control the human activities within the scope of 5× 10~5 people/km^2 to 9.9× 10~5 people/km^2 for the effective control of the size of the affected area by geological environment problems.展开更多
<p> <a name="OLE_LINK14"></a><a name="OLE_LINK13"></a><span style="font-family:Verdana;"><span style="font-family:Verdana;">Based on th...<p> <a name="OLE_LINK14"></a><a name="OLE_LINK13"></a><span style="font-family:Verdana;"><span style="font-family:Verdana;">Based on the panel vector autoregressive model (PVAR) and the panel data of China’s 31 provinces from 2010 to 2019, this paper conducts a quantitative analysis on the dynamic balance relationship between China’s express business volume and economic development status in recent 10 years. The results show that: Firstly, there is a long-term equilibrium relationship between the development level of express industry and the economic development level;Secondly, the relationship between them presents regional heterogeneity (that is, the East, Centre and the West show different characteristics);Finally, in the short term, the development of express delivery industry and economic development can well drive each other, but in the long term, this trend is not obvious, and the economic impact of express delivery industry has a certain lag.展开更多
Administrative divisions are the important foundation of national governance and social development,and the adjustment of administrative divisions is a critical way to promote regional coordinated development.Under th...Administrative divisions are the important foundation of national governance and social development,and the adjustment of administrative divisions is a critical way to promote regional coordinated development.Under the background of globalization and regionalization,timely adjustment of administrative divisions is a major step to reconstruct the regional development pattern.In the perspective of regional coordinated development,this paper constructs an Administrative Rank Potential Energy(ARPE)model to explore the mechanisms of administrative division adjustment(ADA)under coordinated regional development based on the theory of regional interaction,spatial field energy model and power exponential function.The results show that:(1)The development potential and influence of an administrative region are closely related to the administrative jurisdiction,administrative resources,and the potential of regional coordinated development.(2)The growth rate of ARPE in the study area from 2010 to 2015 was 20.7% compared to the period 2005 to 2010,and the potential for coordinated development increased to 3.05% from 0.21% before the"cancelling"the prefecture-level city of Chaohu.(3)The measurement results of the usefulness of ADA can not only distinguish the complex impacts brought about by social development,but also accord with real social and economic development conditions.The ARPE focuses on the both regional integrated development and individual development,thereby serving as a reference for explaining and evaluating adjustments to administrative divisions at the macro-and micro-scales.展开更多
As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility ...As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility as energy absorbers is still in question, particularly when compression is in the direction perpendicular to the axial orientation of cylindrical pores. In this work, the energy absorption of lotus-type porous coppers in the perpendicular direction is investigated at strain rates from 0.001 s^(-1) to^2400 s^(-1). The energy absorption capacity and the energy absorption efficiency are calculated to be4–16 k J/kg and 0.32–0.7, respectively, slightly inferior to metal foams and the same porous solid compressed in the parallel direction due to the shortened extent of the plateau stress region. The deformation mechanism is examined experimentally in conjunction with finite element modeling. Both suggest that gradual squeeze and collapse of pores are the mechanisms accommodating the energy absorption. The deformation is generally evenly distributed over pore ligaments and independent of strain rate.展开更多
基金This project was sponsored by the State Seismological Bureau (85070102), China
文摘Two aspects of a new method,which can be used for seismic zoning,are introduced in this paper.On the one hand,the approach to estimate b value and annual activity rate proposed by Kijko and Sellevoll needs to use the earthquake catalogue.The existing earthquake catalogue contains both historical and recent instrumental data sets and it is inadequate to use only one part.Combining the large number of historical events with recent complete records and taking the magnitude uncertainty into account,Kijko’s method gives the maximum likelihood estimation of b value and annual activity rate,which might be more realistic.On the other hand,this method considers the source zone boundary uncertainty in seismic hazard analysis,which means the earthquake activity rate across a boundary of a source zone changes smoothly instead of abruptly and avoids too large a gradient in the calculated results.
基金funded partly by the National Key Research and Development Program of China (Project No.2017YFD0600601-01-04)the Fundamental Research Funds for the Central Universities (2572019CP15)。
文摘To explore the influence of meteorological variables on the growth of Korean pine(Pinus koraiensis Sieb.et Zucc.) plantations and provide a scientific reference for the production and management of Korean pine,three approaches to interpolate meteorological variables during the growing season(i.e.,May-September) were compared in Heilongjiang Province,China.Optimized meteorological variable interpolation results were then combined with stand and individual tree variables,based on data from 56 sample plots and 2886 sample trees from Korean pine plantations in two regions of the province to develop an individualtree diameter growth model(Model I) and an individualtree diameter growth model with meteorological variables(Model Ⅱ) using a stepwise regression method.Moreover,an individual-tree diameter growth model with regional effects(Model Ⅲ) was developed using dummy variables in the regression,and the significance of introducing these dummy variables was verified with an F-test statistical analysis.The models were validated using an independent data set,and the predictive performance of the three models was assessed via the adjusted coefficient of determination(R_(a)^(2)) and root mean square error(RMSE).The results suggest that the growth increment in tree diameter of Korean pine plantations was significantly correlated with the natural logarithm of initial diameter(ln D),stand basal area(BAS),logarithmic deformation of the stand density index(ln SDI),ratio of basal area of trees larger than the subject tree to their initial diameter at breast height(DBH)(BAL/D),and the maximum growingseason precipitation(Pgmax).The individual-tree diameter growth models of Korean pine plantations developed in this study will provide a good basis for estimating and predicting growth increments of Korean pine forests over larger areas.
基金supported by National Natural Science Foundation of China(Grant No.3116015731560209)Application Fundamental Research Plan Project of Yunnan Province,China(Grant No.2012FD027)
文摘A total of 128 Simao pine trees (Pinus kesiya var. langbianensis) from three regions of Pu'er City, Yunnan Province, People's Republic of China, were destructively sampled to obtain tree aboveground biomass (AGB). Tree variables such as diameter at breast height and total height, and topographical factors such as altitude, aspect of slope, and degree of slope were recorded. We considered the region and site quality classes as the ran- dom-effects, and the topographic variables as the fixed- effects. We fitted a total of eight models as follows: least- squares nonlinear models (BM), least-squares nonlinear models with the topographic factors (BMT), nonlinear mixed-effects models with region as single random-effects (NLME-RE), nonlinear mixed-effects models with site as single random-effects (NLME-SE), nonlinear mixed-ef- fects models with the two-level nested region and site random-effects (TLNLME), NLME-RE with the fixed-ef- fects of topographic factors (NLMET-RE), NLME-SE with the fixed-effects of topographic factors (NLMET-SE), and TLNLME with the fixed-effects of topographic factors (TLNLMET). The eight models were compared by modelfitting and prediction statistics. The results showed: model fitting was improved by considering random-effects of region or site, or both. The models with the fixed-effects of topographic factors had better model fitting. According to AIC and BIC, the model fitting was ranked as TLNLME 〉 NLMET-RE 〉 NLME-RE.〉 NLMET-SE 〉 TLNLMET 〉 NLME-SE 〉 BMT 〉 BM. The differences among these models for model prediction were small. The model pre- diction was ranked as TLNLME 〉 NLME-RE 〉 NLME- SE 〉 NLMET-RE 〉 NLMET-SE 〉 TLNLMET 〉 BMT 〉 BM. However, all eight models had relatively high prediction precision (〉90 %). Thus, the best model should be chosen based on the available data when using the model to predict individual tree AGB.
基金supported by Geological Map of Groundwater Resources and Environment of China and Surrounding Areas(12120113014200)Series Maps of Karst Environment Geology of China and South East Asia(12120114006401,12120114006301)
文摘This paper summarizes the negative effects on geological environment caused by groundwater exploitation and its distribution. There are seven main types of the geological environment negative effects, which are generally as follows:(1) Constant decrease of groundwater level is mainly distributed in China(East Asia), India(South Asia), Tajikistan(Central Asia) and Saudi Arabia(West Asia);(2) land subsidence occurs mainly in eastern plains of East Asia and west Siberian Plain of North Asia;(3) seawater intrusion occurs mainly in China, Japan and South Korea in East Asia, Philippines and Indonesia in Southeast Asia, the Indian coastal areas in South Asia;(4) groundwater level decline caused by groundwater exploitation in oil fields;(5) mining collapse is mainly in 50° to 70° north latitude band;(6) the total area of karst collapse in China of East Asia is as much as 197.05 km^2; and(7) ground fracture is mainly distributed in the North China Plain, Fenwei Plain and the Yangtze River Delta. Asia can be divided into 6 zones in terms of the geological environment negative effect caused by groundwater exploitation. According to analysis, with the increasing intensity of human activities, geological environment issues become more and more serious, therefore it is vital to control the human activities within the scope of 5× 10~5 people/km^2 to 9.9× 10~5 people/km^2 for the effective control of the size of the affected area by geological environment problems.
文摘<p> <a name="OLE_LINK14"></a><a name="OLE_LINK13"></a><span style="font-family:Verdana;"><span style="font-family:Verdana;">Based on the panel vector autoregressive model (PVAR) and the panel data of China’s 31 provinces from 2010 to 2019, this paper conducts a quantitative analysis on the dynamic balance relationship between China’s express business volume and economic development status in recent 10 years. The results show that: Firstly, there is a long-term equilibrium relationship between the development level of express industry and the economic development level;Secondly, the relationship between them presents regional heterogeneity (that is, the East, Centre and the West show different characteristics);Finally, in the short term, the development of express delivery industry and economic development can well drive each other, but in the long term, this trend is not obvious, and the economic impact of express delivery industry has a certain lag.
基金National Natural Science Foundation of China,No.41871151。
文摘Administrative divisions are the important foundation of national governance and social development,and the adjustment of administrative divisions is a critical way to promote regional coordinated development.Under the background of globalization and regionalization,timely adjustment of administrative divisions is a major step to reconstruct the regional development pattern.In the perspective of regional coordinated development,this paper constructs an Administrative Rank Potential Energy(ARPE)model to explore the mechanisms of administrative division adjustment(ADA)under coordinated regional development based on the theory of regional interaction,spatial field energy model and power exponential function.The results show that:(1)The development potential and influence of an administrative region are closely related to the administrative jurisdiction,administrative resources,and the potential of regional coordinated development.(2)The growth rate of ARPE in the study area from 2010 to 2015 was 20.7% compared to the period 2005 to 2010,and the potential for coordinated development increased to 3.05% from 0.21% before the"cancelling"the prefecture-level city of Chaohu.(3)The measurement results of the usefulness of ADA can not only distinguish the complex impacts brought about by social development,but also accord with real social and economic development conditions.The ARPE focuses on the both regional integrated development and individual development,thereby serving as a reference for explaining and evaluating adjustments to administrative divisions at the macro-and micro-scales.
基金financial support from the National Natural Science Foundation of China (Grant No. 50904004)
文摘As metallic foams used for energy absorption in the automotive and aerospace industries, recently invented lotus-type porous metals are viewed as potential energy absorbers. Yet, solid conclusion on their eligibility as energy absorbers is still in question, particularly when compression is in the direction perpendicular to the axial orientation of cylindrical pores. In this work, the energy absorption of lotus-type porous coppers in the perpendicular direction is investigated at strain rates from 0.001 s^(-1) to^2400 s^(-1). The energy absorption capacity and the energy absorption efficiency are calculated to be4–16 k J/kg and 0.32–0.7, respectively, slightly inferior to metal foams and the same porous solid compressed in the parallel direction due to the shortened extent of the plateau stress region. The deformation mechanism is examined experimentally in conjunction with finite element modeling. Both suggest that gradual squeeze and collapse of pores are the mechanisms accommodating the energy absorption. The deformation is generally evenly distributed over pore ligaments and independent of strain rate.