Exploring the effective and efficient path of agricultural carbon emission reduction in Henan Province is of great significance to optimizing the strategic layout of China's agricultural emission reduction and car...Exploring the effective and efficient path of agricultural carbon emission reduction in Henan Province is of great significance to optimizing the strategic layout of China's agricultural emission reduction and carbon sequestration.Accordingly,the agricultural carbon emissions of each county were measured scientifically and then the spatial measurement model was utilized to clarify the spatial and temporal evolution trend and spatial effect mechanism of agricultural carbon emissions based on the county data of Henan Province from 2010 to 2020.The results showed that:(1)in 2020,the total agricultural carbon emissions were 134.7274 million tons,with the high distribution in the southeast and low distribution in the northwest;(2)the spatial dependence of agricultural carbon emissions showed a four-stage trend of fluctuating down-continuing up-plummeting-fluctuating up again,and the spatial heterogeneity was dominated by low-low agglomeration,followed by high-low agglomeration;(3)there was an inverted U curve relationship between the level of agricultural economic development and agricultural carbon emissions.The increase in the level of agricultural mechanization and urbanization rate significantly reduced agricultural carbon emissions.The opposite was true for the financial support for agriculture,the income level of rural residents and the structure of the agricultural industry;(4)in terms of spatial spillover effects,the increase in the level of agricultural development in neighbor counties first increased and then decreased agricultural carbon emissions in Henan Province.The mechanization level and urbanization rate of neighbor counties reduced agricultural carbon emissions in Henan Province,and the opposite was true for the income level of rural residents and the scale utilization of agricultural land.展开更多
The development of digital villages and the expansion of farmers’consumption are important measures for expanding domestic demand and enhancing rural productive forces.Based on provincial panel data from China spanni...The development of digital villages and the expansion of farmers’consumption are important measures for expanding domestic demand and enhancing rural productive forces.Based on provincial panel data from China spanning 2010 to 2022,this paper establishes an evaluation indicator system for the development of digital villages,and empirically examines the impact of the development of digital villages on farmers’consumption growth,as well as its mechanisms,and spatial spillover effects.The results indicate that digital village development significantly promotes growth in the consumption of farmers,with the effects being more pronounced in the central and western regions.Mechanism analysis reveals that digital village development has a significant income-increasing effect and it improves the convenience of payments,both of which serve as important channels for promoting farmers’consumption growth.Further analysis demonstrates the significant spatial spillover effects of digital village development on farmers’consumption growth.Specifically,farmers’consumption growth is not only directly influenced by local digital village development and the demonstration effect of consumption growth in neighboring regions,but it is also indirectly influenced by the digital village development of nearby areas.Therefore,the promotion of digital village development,tailored to local conditions,the broadening of channels for increasing farmers’income,the strengthening of digital inclusive finance,and the rational leveraging of the spatial spillover effects of digital village development can further unleash the potential of farmers’consumption.展开更多
As a new kind of technology in retaining structures, the characteristics of double-row piles are significantly affected by spatial effects. In this paper, double-row piles as a retaining structure are simulated numeri...As a new kind of technology in retaining structures, the characteristics of double-row piles are significantly affected by spatial effects. In this paper, double-row piles as a retaining structure are simulated numerically in three-dimension by finite element software PLAXIS 3D FOUNDATION. The behavior differences of piles in different positions around the foundation pit are analyzed. By changing the parameters, including the length-width ratio, the excavation depth, the distance between rows and the diameter of piles, the variations of the lateral deformation, the bending moment and the earth pressure around the piles are determined. The reasonable values of parameters and some suggestions with consideration of earth pressure are proposed for the design of double-row piles as a retaining structure. The results show that the lateral deformation and bending moment are the largest in the middle of long side of the foundation pit, which is identified as the most unfavorable position. It is indicated that the earth pressure between rows above pit bottom is close to active earth pressure, while the earth pressure between rows under pit bottom is close to static earth pressure. It is suggested that 1/2-2/3 of pile length, 0.6-1.2 m, 3d-6d, and 2d-2.5d be chosen as embedded depth of piles, diameter of piles, distance between rows, and distance between piles, respectively, where d is the pile diameter.展开更多
In this study,an inventory analysis approach was used to investigate the intensity of agricultural non-point source pollution(ANSP)and its spatial convergence at national and provincial levels in China from 1999 to 20...In this study,an inventory analysis approach was used to investigate the intensity of agricultural non-point source pollution(ANSP)and its spatial convergence at national and provincial levels in China from 1999 to 2017.On this basis,spatial factors affecting ANSP were explored by constructing a spatial econometric model.The results indicate that:1)The intensity of China's ANSP emission showed an overall upward trend and an obvious spatial difference,with the values being high in the eastern and central regions and relatively low in the western region.2)Significant spatial agglomeration was shown in China's ANSP intensity,and the agglomeration effect was increasing gradually.3)In the convergence analysis,a spatial lag model was found applicable for interpretation of the ANSP intensity,with the convergence rate being accelerated after considering the spatial factors but slower than that of regional economic growth.4)The spatial factors affecting the ANSP intensity are shown to be reduced by improving agricultural infrastructure investment,labor-force quality,and crop production ratio,while the expansion of agricultural economy scale and precipitation and runoff have positive impact on ANSP in the study region.However,agricultural research and development(R&D)investment showed no direct significant effect on the ANSP intensity.Meanwhile,improving the quality of the labor force would significantly reduce the ANSP intensity in the surrounding areas,while the precipitation and runoff would significantly increase the pollution of neighboring regions.This research has laid a theoretical basis for formulation and optimization of ANSP prevention strategies in China and related regions.展开更多
Mineral resources exploitation significantly affects the spatial structure and evolutive trend of urbanization in arid areas.In this study,the spatial autocorrelation method and the spatial computation model were used...Mineral resources exploitation significantly affects the spatial structure and evolutive trend of urbanization in arid areas.In this study,the spatial autocorrelation method and the spatial computation model were used to investigate the spatial impacts of mineral resources excavation and processing on comprehensive level of urbanization in the Tarim River Basin,Xinjiang,China for the years of 2000,2006 and 2008.The results are as follows:1)There was a spatial correlation of the development of mineral resources industry and the comprehensive level of urbanization in 2006 and 2008,with the spatial concentration trend rising significantly in 2006 and decreasing in 2008.2)The patterns of local spatial concentration of mineral resources industry and of the comprehensive level of urbanization were relatively stable,and the two patterns showed signs of spatial correlationship.The higher was the degree of the concentration of mineral resources industry,the stronger was its impact on the spatial clustering of urbanization.3)In 2000, mineral resources excavation and processing had a significant positive impact on the comprehensive level of urbanization in the region but not in its adjacent regions.However,in 2008,mineral resources excavation and processing significantly raised the comprehensive level of urbanization not only in the region but also in its neighboring regions.This research demonstrates that the development of mineral resources industry can strongly affect the trends and spatial patterns of urbanization.展开更多
Based on the multi-regional input-output analysis, this paper improves the four traditional input-output formulas about exports resulting in multi-regional carbon emissions spatial effects which include direct effect,...Based on the multi-regional input-output analysis, this paper improves the four traditional input-output formulas about exports resulting in multi-regional carbon emissions spatial effects which include direct effect, indirect effect, spillover effect and feedback effect. And the latter two formulas are to measure the bidirectional influences of carbon emissions induced by regional exports between two regions. The results suggest that the direct effects of Chinese eight regions induced by national exports decreased from 1997 to 2010, and the indirect effects induced by national exports also decreased except the northern coastal region and the northwestern region in China. During this period, most of Chinese coastal regions had strong spillover effects induced by their own exports. The northern coastal region and the eastern coastal region had stronger feedback effects, while the southern coastal region had weaker feedback effects and Beijing-Tianjin region had the weakest feedback effect induced by their exports. All of the inland regions had strong feedback effects, especially for Northwest and Central China, induced by their exports. More attention should be paid to the inter-regional joint efforts in order to effectively achieve Chinese national carbon-reduction target.展开更多
Based on two dimensions of supply and demand,we use six indicators to establish a rural inclusive financial development index and evaluate the development of China's rural inclusive finance. We use spatial panel d...Based on two dimensions of supply and demand,we use six indicators to establish a rural inclusive financial development index and evaluate the development of China's rural inclusive finance. We use spatial panel data model to examine the relationship between financial inclusion and rural poverty. Results show that:( i) both the rural inclusive finance and rural residents' per capita consumption present spatial clustering feature and show significant spatial correlation;( ii) the development of rural inclusive finance has significant spatial effect on poverty alleviation along time and space dimensions. In this study,the paper puts forward policy recommendations on strengthening the rural financial resources flow and constructing diversified rural inclusive financial system.展开更多
Based on Chinese provincial panel data from 2003 to 2014,the spatial dependence between the environment regulation and carbon emissions is tested by spatial autocorrelation analysis. Besides,spatial lag model and spat...Based on Chinese provincial panel data from 2003 to 2014,the spatial dependence between the environment regulation and carbon emissions is tested by spatial autocorrelation analysis. Besides,spatial lag model and spatial error model are built to empirically test the marginal effect of environmental regulation on carbon emissions and its spatial effect. The result shows that the influence trajectory of environmental regulation on carbon emissions performances inverted ＂ U＂ type. It is ＂ green paradox effect＂ before the inflection point and ＂ reversed transmission reduction effect＂ after the inflection point. Moreover,the carbon emissions show significant spatial spillover effect. In order to achieve the desired effect of environmental regulation and promote carbon reduction,we should increase the environmental regulation intensity reasonably,select rational environmental regulation policy tools,and sufficiently consider the spatial spillover effect of carbon emissions.展开更多
Carbon dots(CDs)with room-temperature phosphorescence(RTP)have attracted dramatically growing interest in optical functional materials.However,the photoluminescence mechanism of CDs is still a vital and challenging to...Carbon dots(CDs)with room-temperature phosphorescence(RTP)have attracted dramatically growing interest in optical functional materials.However,the photoluminescence mechanism of CDs is still a vital and challenging topic.In this work,we prepared CD-based RTP materials via melting boric acid with various lengths of alkyl amine compounds as precursors.The spatial effect on the structure and the RTP properties of CDs were systematically investigated.With the increase in carbon chain length,the interplanar spacing of the carbon core expands and crosslink-enhanced emission weakens,resulting in a decrease in the phosphorescence intensity and lifetimes.Meanwhile,based on triplet-to-singlet resonance energy transfer,we employed intense and long-lived phosphorescence CDs as the donor and short-lived fluorescent dyes as the acceptor to achieve long-lived multicolor afterglow.By the triplet-to-singlet resonance energy transfer,the afterglow color can change from green to orange.The afterglow lifetimes are more than 0.9 s.Thanks to the outstanding afterglow properties,the composites were used for timeresolved and multiple-color advanced anticounterfeiting.This work will promote the design of multicolor and long-lived afterglow materials and expand their applications.展开更多
Regarding excavation-damaged zone （EDZ） around underground opening as non-homogeneous rockmass with spatial deterioration effect on stuffiness and strength, a parametric model of EDZ using radius-displacement-depend...Regarding excavation-damaged zone （EDZ） around underground opening as non-homogeneous rockmass with spatial deterioration effect on stuffiness and strength, a parametric model of EDZ using radius-displacement-dependent deformation modulus （RDDM） was proposed. Considering the nonlinearity characteristic of deformation and locality otherness of surrounding rock, deterioration parameter field of deformation modulus of rockmass around opening was quantitatively calculated through a given function. Applicability for multi-cavern condition and parameter sensibility of the model was analyzed by numerical experiments using synthetic data. Furthermore, the model was applied to identify EDZ of underground caverns of Pubugou hydropower station by calculating deterioration parameter field. Based on the parametric analysis of spatial effect and geological investigation, it is recognized that large radial deformation of deep fractured rock at the spandrel position and insufficient supporting bolts mainly result in great deformation pressure to act on the shotcrete and cause partial crack and spalling. It is shown that deterioration parameter field along the longitudinal axis of main powerhouse is evidently non-homogeneous in space and distributes exponentially along the radius from the opening. The model provides a simple and convenient way to identify the EDZ in the working state for rapid construction feedback analysis and support optimization of underground cavem from quantitative point of view and also aids in interpreting monitoring displacements and estimating support requirements.展开更多
This thesis is to study spatial effect of education output on economic growth through the use of spatial measurement technique. According to the study: there’s the presence of spatial spillover effects in human capit...This thesis is to study spatial effect of education output on economic growth through the use of spatial measurement technique. According to the study: there’s the presence of spatial spillover effects in human capital, economic growth, and others;in previous years, human capital depended on mainly the employers with junior school education or below;in recent years, with the reduction of employers with junior school education or below, employers with regular higher education can best promote the economic growth. However, it’s very difficult for human capital with vocational education to promote economic growth, especially in recent years. Therefore, from the perspective of long-term economic growth, China should focus on culturing professional talents and put more resources into the development of vocational education while developing the higher education.展开更多
Based on the 30 provinces(cities,autonomous regions)panel data of China from 2007 to 2016,this paper establishes a Spatial Durbin Model to explore the spatial effects of green tax policies in broad and narrow sense on...Based on the 30 provinces(cities,autonomous regions)panel data of China from 2007 to 2016,this paper establishes a Spatial Durbin Model to explore the spatial effects of green tax policies in broad and narrow sense on energy efficiency.The results show that:(1)China's provincial energy efficiency has significant spatial correlation.(2)the relationship between the intensity of narrow sense green tax policy and the energy efficiency of the surrounding areas is an inverted U-shaped curve.(3)the relationship between the generalized green tax policy intensity and the energy efficiency of the surrounding areas is a U-shaped curve.展开更多
Utilizing provincial panel data from 2014 to 2020,this study employs a fixed effect model,a threshold effect model,and a spatial lag model to empirically examine the correlation between digital economic development an...Utilizing provincial panel data from 2014 to 2020,this study employs a fixed effect model,a threshold effect model,and a spatial lag model to empirically examine the correlation between digital economic development and carbon productivity.The findings indicate that digital economic development significantly contributes to the enhancement of carbon productivity in the long term.Furthermore,through instrumental variable method,replacement of explanatory variables and other methods to test its endogeneity and stability,the results remain robust.In terms of regional heterogeneity,the impact of digital economic development on carbon productivity is less pronounced in the central and western regions compared to the eastern region.Additionally,further investigation reveals that industrial structure upgrading and science and technology investment level exhibit different threshold effects on the influence of digital economy development level on carbon productivity.Moreover,there is a significant spatial spillover effect of digital economy development on carbon productivity with H-H and L-L agglomeration spatial correlation.展开更多
Based on provincial panel data of water footprint and grey water footprint, and with the help of data envelopment analysis model considering and without considering the unde- sirable output, this paper estimates the w...Based on provincial panel data of water footprint and grey water footprint, and with the help of data envelopment analysis model considering and without considering the unde- sirable output, this paper estimates the water resources utilization efficiency in China from 1997 to 2011. The spatial weighting matrix based on economy-spatial distance function is established to discuss spatial autocorrelation of water resources utilization efficiency. With the help of absolute/3-convergence model, this paper concludes that there exists/%convergence in the water resources utilization efficiency. Under the conditions of considering and without considering the undesirable output, it takes about 52.6 and 5.6 years respectively to achieve the extent of half of convergence. By mean of the spatial Durbin econometric model, this paper studies spatial spillover effects of the provincial water resources utilization efficiency in China. The results are as follows. 1） With considering and without considering the undesir- able output, there is significant spatial correlation in provincial water resource efficiency in China. 2） Under the two cases, the spatial autoregressive coefficients （p） are 0.278 and 0.507 respectively, at 1% significance level. There exist the spatial spillover effects of provin- cial water resources utilization efficiency. 3） With considering the undesirable output, these factors of the education funds, the transportation infrastructure, and the industrial and agri- cultural water consumption proportion have positive impacts. These factors of foreign direct investment, the industry value-added water consumption per ten thousand yuan, per capita water consumption, and the total precipitation have negative impacts. 4） Without considering the undesirable output, the factor of GDP per laborer has a greater positive significant influ- ence on the water resources utilization efficiency. However the facts of industry value-added water consumption in ten thousand yuan and the transportation infrastructure have no sig- nificant influence. 5） Regardless of undesirable output of water resources utilization efficiency the assessment of the present real water resources utilization in China will be distorted and policy-making will be misled. The water efficiency measure considering environmental factors （such as gray water footprint） is more reasonable.展开更多
As an organic part of urban functions, industrial land is of great significance to the urban healthy and sustainable development. Although consensus has been reached on the evolutionary characteristics and spatial eff...As an organic part of urban functions, industrial land is of great significance to the urban healthy and sustainable development. Although consensus has been reached on the evolutionary characteristics and spatial effects of industrial land, the influence mechanism of the evolution of industrial land on urban space still needs further exploration. Therefore, the evolution of industrial land in Xi’an from 2003 to 2019 is analyzed by the land use change matrixes, mixed degrees index, and sprawl index according to the multisource data. The results show that the scale change of industrial land is characterized by an inverted U-shaped curve and development zone-oriented spatial aggregation. Suburbanization, the conversion of agricultural land to industrial land in the suburbs, has intensified urban sprawl, resulting in more serious work-living imbalance and traffic congestion.Deindustrialization, the conversion of industrial land to residential, commercial, and business facilities land in the city center, has promoted urban sprawl, generated a large amount of construction waste, and caused a waste of resources. Based on the complex factors such as urban planning, land finance, and development zones, this study contributes to the research of the improvement of the rationality of urban land layout by revealing the influence mechanism of the evolution of industrial land on urban space.展开更多
In recent decades, Urban Heat Island Effects have become more pronounced and more widely examined. Despite great technological advances, our current societies still experience great spatial disparity in urban forest a...In recent decades, Urban Heat Island Effects have become more pronounced and more widely examined. Despite great technological advances, our current societies still experience great spatial disparity in urban forest access. Urban Heat Island Effects are measurable phenomenon that are being experienced by the world’s most urbanized areas, including increased summer high temperatures and lower evapotranspiration from having impervious surfaces instead of vegetation and trees. Tree canopy cover is our natural mitigation tool that absorbs sunlight for photosynthesis, protects humans from incoming radiation, and releases cooling moisture into the air. Unfortunately, urban areas typically have low levels of vegetation. Vulnerable urban communities are lower-income areas of inner cities with less access to heat protection like air conditioners. This study uses mean evapotranspiration levels to assess the variability of urban heat island effects across the state of Tennessee. Results show that increased developed land surface cover in Tennessee creates measurable changes in atmospheric evapotranspiration. As a result, the mean evapotranspiration levels in areas with less tree vegetation are significantly lower than the surrounding forested areas. Central areas of urban cities in Tennessee had lower mean evapotranspiration recordings than surrounding areas with less development. This work demonstrates the need for increased tree canopy coverage.展开更多
Spatial spillover effects,either positive or negative,of transport infrastructure,highways/expressways,etc.,on regional economic growth are proposed.Using the panel data for 11 cities of Zhejiang province from 1994 to...Spatial spillover effects,either positive or negative,of transport infrastructure,highways/expressways,etc.,on regional economic growth are proposed.Using the panel data for 11 cities of Zhejiang province from 1994 to 2003,a spatial production function is applied to examine the spatial spillovers which can be generated as a positive output spillover from the transport infrastructure between neighboring cities.Some spatial weighted matrices are adopted to define different neighboring cities to measure how easily factors or economic activities can migrate between regions.The estimation results show that the output elasticity of the highway infrastructure in 11 cities are all insignificant at a 5% significance level;hence,highway infrastructure in a region cannot explain the same region's economic growth.On the other hand,the highway infrastructure of other contiguous regions has positive spillover effects on a same region's economic growth.展开更多
To explore the influence of substituent groups on thermally induced curing,eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized.The t...To explore the influence of substituent groups on thermally induced curing,eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized.The thermal curing of these bio-based benzoxazines was studied in detail.Combined with the curing reaction kinetics,simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values,the spatial and electronic effects of different substituent groups on the curing of benzoxazine was explored.It was found that when the substituent was located at the position directly connected to the N atom,the steric hindrance effect of the group was dominant.When the substituent group was located on the benzene ring connected to the O atom,both the electronic effect and the spatial effect influenced the curing of benzoxazine.When an electron-withdrawing group was connected ortho position to the O atom,the curing reaction was promoted due to the decreased electron cloud density of O-on the oxazine ring,making the C-O bond easier to break.When an electron-donating group was connected to the meta position of the O atom it also promoted the curing reaction,possibly because it increased the electron cloud density of the+CH2 reaction site and thereby facilitated electrophilic substitution via attack of+CH2 on the cross linking reaction centre.This work provides a deeper understanding of how spatial and electronic effects of substituents affect the curing of benzoxazine.展开更多
The Yangtze River Delta(YRD) is a region in China with a serious contradiction between economic growth and environmental pollution. Exploring the spatiotemporal effects and influencing factors of air pollution in the ...The Yangtze River Delta(YRD) is a region in China with a serious contradiction between economic growth and environmental pollution. Exploring the spatiotemporal effects and influencing factors of air pollution in the region is highly important for formulating policies to promote the high-quality development of urban industries. This study uses the spatial Durbin model(SDM) to analyze the local direct and spatial spillover effects of industrial transformation on air pollution and quantifies the contribution of each factor. From 2008 to 2018, there was a significant spatial agglomeration of industrial sulfur dioxide emissions(ISDE) in the YRD, and every 1% increase in ISDE led to a synchronous increase of 0.603% in the ISDE in adjacent cities. The industrial scale index(ISCI) and industrial structure index(ISTI), as the core factors of industrial transformation, significantly affect the emissions of sulfur dioxide in the YRD, and the elastic coefficients are 0.677 and-0.368, respectively. The order of the direct effect of the explanatory variables on local ISDE is ISCI>ISTI>foreign direct investment(FDI)>enterprise technological innovation(ETI)>environmental regulation(ER)> per capita GDP(PGDP). Similarly, the order of the spatial spillover effect of all variables on ISDE in adjacent cities is ISCI>PGDP>FDI>ETI>ISTI>ER, and the coefficients of the ISCI and ISTI are 1.531 and 0.113, respectively. This study contributes to the existing research that verifies the environmental Kuznets curve in the YRD, denies the pollution heaven hypothesis, indicates the Porter hypothesis, and provides empirical evidence for the formation mechanism of regional environmental pollution from a spatial spillover perspective.展开更多
In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission inten...In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission intensity in 283 Chinese cities from 1992 to 2013. The following results were obtained.(1) Nuclear density estimation shows that the overall average carbon intensity of cities in China has decreased, with differences gradually narrowing.(2) The spatial autocorrelation Moran's I index indicates significant spatial agglomeration of carbon emission intensity is gradually increasing; however, differences between regions have remained stable.(3) Spatial Markov chain analysis shows a Matthew effect in China's urban carbon emission intensity. In addition, low-intensity and high-intensity cities characteristically maintain their initial state during the transition period. Furthermore, there is a clear "Spatial Spillover" effect in urban carbon emission intensity and there is heterogeneity in the spillover effect in different regional contexts; that is, if a city is near a city with low carbon emission intensity, the carbon emission intensity of the first city has a higher probability of upward transfer, and vice versa.(4) Panel quantile results indicate that in cities with low carbon emission intensity, economic growth, technological progress, and appropriate population density play an important role in reducing emissions. In addition, foreign investment intensity and traffic emissions are the main factors that increase carbon emission intensity. In cities with high carbon intensity, population density is an important emission reduction factor, and technological progress has no significant effect. In contrast, industrial emissions, extensive capital investment, and urban land expansion are the main factors driving the increase in carbon intensity.展开更多
基金Supported by the Humanities and Social Sciences Planning Program of the Ministry of Education(23YJA790027)。
文摘Exploring the effective and efficient path of agricultural carbon emission reduction in Henan Province is of great significance to optimizing the strategic layout of China's agricultural emission reduction and carbon sequestration.Accordingly,the agricultural carbon emissions of each county were measured scientifically and then the spatial measurement model was utilized to clarify the spatial and temporal evolution trend and spatial effect mechanism of agricultural carbon emissions based on the county data of Henan Province from 2010 to 2020.The results showed that:(1)in 2020,the total agricultural carbon emissions were 134.7274 million tons,with the high distribution in the southeast and low distribution in the northwest;(2)the spatial dependence of agricultural carbon emissions showed a four-stage trend of fluctuating down-continuing up-plummeting-fluctuating up again,and the spatial heterogeneity was dominated by low-low agglomeration,followed by high-low agglomeration;(3)there was an inverted U curve relationship between the level of agricultural economic development and agricultural carbon emissions.The increase in the level of agricultural mechanization and urbanization rate significantly reduced agricultural carbon emissions.The opposite was true for the financial support for agriculture,the income level of rural residents and the structure of the agricultural industry;(4)in terms of spatial spillover effects,the increase in the level of agricultural development in neighbor counties first increased and then decreased agricultural carbon emissions in Henan Province.The mechanization level and urbanization rate of neighbor counties reduced agricultural carbon emissions in Henan Province,and the opposite was true for the income level of rural residents and the scale utilization of agricultural land.
基金the initial outcome of the Research on Strategies and Paths for Digital Economy Promoting Green Development Transformation of Chengdu-Chongqing Economic Circle(ID:2023ZDSC10)a major project under Chongqing’s Social Science Planning for the construction of the Chengdu-Chongqing Economic Circle,the Research on Paths for Digital Village Development Empowering Western China to Narrow the Urban-Rural Income Gap in the New Development Stage(ID:SWU2209220)a capacity enhancement project supported by Central Government’s Special Fund for the Basic Research Activities of Colleges and Universities,and the Dual Circulation in the National Economy Empowering Rural Revitalization(ID:SWUPilotPlan025)under the 2035 Pilot Plan of Southwest University.
文摘The development of digital villages and the expansion of farmers’consumption are important measures for expanding domestic demand and enhancing rural productive forces.Based on provincial panel data from China spanning 2010 to 2022,this paper establishes an evaluation indicator system for the development of digital villages,and empirically examines the impact of the development of digital villages on farmers’consumption growth,as well as its mechanisms,and spatial spillover effects.The results indicate that digital village development significantly promotes growth in the consumption of farmers,with the effects being more pronounced in the central and western regions.Mechanism analysis reveals that digital village development has a significant income-increasing effect and it improves the convenience of payments,both of which serve as important channels for promoting farmers’consumption growth.Further analysis demonstrates the significant spatial spillover effects of digital village development on farmers’consumption growth.Specifically,farmers’consumption growth is not only directly influenced by local digital village development and the demonstration effect of consumption growth in neighboring regions,but it is also indirectly influenced by the digital village development of nearby areas.Therefore,the promotion of digital village development,tailored to local conditions,the broadening of channels for increasing farmers’income,the strengthening of digital inclusive finance,and the rational leveraging of the spatial spillover effects of digital village development can further unleash the potential of farmers’consumption.
文摘As a new kind of technology in retaining structures, the characteristics of double-row piles are significantly affected by spatial effects. In this paper, double-row piles as a retaining structure are simulated numerically in three-dimension by finite element software PLAXIS 3D FOUNDATION. The behavior differences of piles in different positions around the foundation pit are analyzed. By changing the parameters, including the length-width ratio, the excavation depth, the distance between rows and the diameter of piles, the variations of the lateral deformation, the bending moment and the earth pressure around the piles are determined. The reasonable values of parameters and some suggestions with consideration of earth pressure are proposed for the design of double-row piles as a retaining structure. The results show that the lateral deformation and bending moment are the largest in the middle of long side of the foundation pit, which is identified as the most unfavorable position. It is indicated that the earth pressure between rows above pit bottom is close to active earth pressure, while the earth pressure between rows under pit bottom is close to static earth pressure. It is suggested that 1/2-2/3 of pile length, 0.6-1.2 m, 3d-6d, and 2d-2.5d be chosen as embedded depth of piles, diameter of piles, distance between rows, and distance between piles, respectively, where d is the pile diameter.
基金Under the auspices of Key Program of the National Social Science Fund of China(No.16ASH007)。
文摘In this study,an inventory analysis approach was used to investigate the intensity of agricultural non-point source pollution(ANSP)and its spatial convergence at national and provincial levels in China from 1999 to 2017.On this basis,spatial factors affecting ANSP were explored by constructing a spatial econometric model.The results indicate that:1)The intensity of China's ANSP emission showed an overall upward trend and an obvious spatial difference,with the values being high in the eastern and central regions and relatively low in the western region.2)Significant spatial agglomeration was shown in China's ANSP intensity,and the agglomeration effect was increasing gradually.3)In the convergence analysis,a spatial lag model was found applicable for interpretation of the ANSP intensity,with the convergence rate being accelerated after considering the spatial factors but slower than that of regional economic growth.4)The spatial factors affecting the ANSP intensity are shown to be reduced by improving agricultural infrastructure investment,labor-force quality,and crop production ratio,while the expansion of agricultural economy scale and precipitation and runoff have positive impact on ANSP in the study region.However,agricultural research and development(R&D)investment showed no direct significant effect on the ANSP intensity.Meanwhile,improving the quality of the labor force would significantly reduce the ANSP intensity in the surrounding areas,while the precipitation and runoff would significantly increase the pollution of neighboring regions.This research has laid a theoretical basis for formulation and optimization of ANSP prevention strategies in China and related regions.
基金Under the auspices of Chinese Academy of Sciences Western Doctor Special Financial Aid(No.XBBS200812)National Natural Science Foundation of China(No.40601032)
文摘Mineral resources exploitation significantly affects the spatial structure and evolutive trend of urbanization in arid areas.In this study,the spatial autocorrelation method and the spatial computation model were used to investigate the spatial impacts of mineral resources excavation and processing on comprehensive level of urbanization in the Tarim River Basin,Xinjiang,China for the years of 2000,2006 and 2008.The results are as follows:1)There was a spatial correlation of the development of mineral resources industry and the comprehensive level of urbanization in 2006 and 2008,with the spatial concentration trend rising significantly in 2006 and decreasing in 2008.2)The patterns of local spatial concentration of mineral resources industry and of the comprehensive level of urbanization were relatively stable,and the two patterns showed signs of spatial correlationship.The higher was the degree of the concentration of mineral resources industry,the stronger was its impact on the spatial clustering of urbanization.3)In 2000, mineral resources excavation and processing had a significant positive impact on the comprehensive level of urbanization in the region but not in its adjacent regions.However,in 2008,mineral resources excavation and processing significantly raised the comprehensive level of urbanization not only in the region but also in its neighboring regions.This research demonstrates that the development of mineral resources industry can strongly affect the trends and spatial patterns of urbanization.
基金National Natural Science Foundation of China, No.41201129, No.41125005
文摘Based on the multi-regional input-output analysis, this paper improves the four traditional input-output formulas about exports resulting in multi-regional carbon emissions spatial effects which include direct effect, indirect effect, spillover effect and feedback effect. And the latter two formulas are to measure the bidirectional influences of carbon emissions induced by regional exports between two regions. The results suggest that the direct effects of Chinese eight regions induced by national exports decreased from 1997 to 2010, and the indirect effects induced by national exports also decreased except the northern coastal region and the northwestern region in China. During this period, most of Chinese coastal regions had strong spillover effects induced by their own exports. The northern coastal region and the eastern coastal region had stronger feedback effects, while the southern coastal region had weaker feedback effects and Beijing-Tianjin region had the weakest feedback effect induced by their exports. All of the inland regions had strong feedback effects, especially for Northwest and Central China, induced by their exports. More attention should be paid to the inter-regional joint efforts in order to effectively achieve Chinese national carbon-reduction target.
文摘Based on two dimensions of supply and demand,we use six indicators to establish a rural inclusive financial development index and evaluate the development of China's rural inclusive finance. We use spatial panel data model to examine the relationship between financial inclusion and rural poverty. Results show that:( i) both the rural inclusive finance and rural residents' per capita consumption present spatial clustering feature and show significant spatial correlation;( ii) the development of rural inclusive finance has significant spatial effect on poverty alleviation along time and space dimensions. In this study,the paper puts forward policy recommendations on strengthening the rural financial resources flow and constructing diversified rural inclusive financial system.
基金Supported by Social Science Fund Project of Hunan Province(16YBA155)
文摘Based on Chinese provincial panel data from 2003 to 2014,the spatial dependence between the environment regulation and carbon emissions is tested by spatial autocorrelation analysis. Besides,spatial lag model and spatial error model are built to empirically test the marginal effect of environmental regulation on carbon emissions and its spatial effect. The result shows that the influence trajectory of environmental regulation on carbon emissions performances inverted ＂ U＂ type. It is ＂ green paradox effect＂ before the inflection point and ＂ reversed transmission reduction effect＂ after the inflection point. Moreover,the carbon emissions show significant spatial spillover effect. In order to achieve the desired effect of environmental regulation and promote carbon reduction,we should increase the environmental regulation intensity reasonably,select rational environmental regulation policy tools,and sufficiently consider the spatial spillover effect of carbon emissions.
基金The authors greatly acknowledge the Natural Science Foundation of Jiangsu Province(No.BK20220351)Natural Science Foundation of the Jiangsu Higher Education Institutions of China(No.22KJB150027)for financial support.
文摘Carbon dots(CDs)with room-temperature phosphorescence(RTP)have attracted dramatically growing interest in optical functional materials.However,the photoluminescence mechanism of CDs is still a vital and challenging topic.In this work,we prepared CD-based RTP materials via melting boric acid with various lengths of alkyl amine compounds as precursors.The spatial effect on the structure and the RTP properties of CDs were systematically investigated.With the increase in carbon chain length,the interplanar spacing of the carbon core expands and crosslink-enhanced emission weakens,resulting in a decrease in the phosphorescence intensity and lifetimes.Meanwhile,based on triplet-to-singlet resonance energy transfer,we employed intense and long-lived phosphorescence CDs as the donor and short-lived fluorescent dyes as the acceptor to achieve long-lived multicolor afterglow.By the triplet-to-singlet resonance energy transfer,the afterglow color can change from green to orange.The afterglow lifetimes are more than 0.9 s.Thanks to the outstanding afterglow properties,the composites were used for timeresolved and multiple-color advanced anticounterfeiting.This work will promote the design of multicolor and long-lived afterglow materials and expand their applications.
基金Project(2010CB732005) supported by the National Basic Research Program of ChinaProjects(51279136, 51209164) supported by the National Natural Science Foundation of China
文摘Regarding excavation-damaged zone （EDZ） around underground opening as non-homogeneous rockmass with spatial deterioration effect on stuffiness and strength, a parametric model of EDZ using radius-displacement-dependent deformation modulus （RDDM） was proposed. Considering the nonlinearity characteristic of deformation and locality otherness of surrounding rock, deterioration parameter field of deformation modulus of rockmass around opening was quantitatively calculated through a given function. Applicability for multi-cavern condition and parameter sensibility of the model was analyzed by numerical experiments using synthetic data. Furthermore, the model was applied to identify EDZ of underground caverns of Pubugou hydropower station by calculating deterioration parameter field. Based on the parametric analysis of spatial effect and geological investigation, it is recognized that large radial deformation of deep fractured rock at the spandrel position and insufficient supporting bolts mainly result in great deformation pressure to act on the shotcrete and cause partial crack and spalling. It is shown that deterioration parameter field along the longitudinal axis of main powerhouse is evidently non-homogeneous in space and distributes exponentially along the radius from the opening. The model provides a simple and convenient way to identify the EDZ in the working state for rapid construction feedback analysis and support optimization of underground cavem from quantitative point of view and also aids in interpreting monitoring displacements and estimating support requirements.
文摘This thesis is to study spatial effect of education output on economic growth through the use of spatial measurement technique. According to the study: there’s the presence of spatial spillover effects in human capital, economic growth, and others;in previous years, human capital depended on mainly the employers with junior school education or below;in recent years, with the reduction of employers with junior school education or below, employers with regular higher education can best promote the economic growth. However, it’s very difficult for human capital with vocational education to promote economic growth, especially in recent years. Therefore, from the perspective of long-term economic growth, China should focus on culturing professional talents and put more resources into the development of vocational education while developing the higher education.
文摘Based on the 30 provinces(cities,autonomous regions)panel data of China from 2007 to 2016,this paper establishes a Spatial Durbin Model to explore the spatial effects of green tax policies in broad and narrow sense on energy efficiency.The results show that:(1)China's provincial energy efficiency has significant spatial correlation.(2)the relationship between the intensity of narrow sense green tax policy and the energy efficiency of the surrounding areas is an inverted U-shaped curve.(3)the relationship between the generalized green tax policy intensity and the energy efficiency of the surrounding areas is a U-shaped curve.
文摘Utilizing provincial panel data from 2014 to 2020,this study employs a fixed effect model,a threshold effect model,and a spatial lag model to empirically examine the correlation between digital economic development and carbon productivity.The findings indicate that digital economic development significantly contributes to the enhancement of carbon productivity in the long term.Furthermore,through instrumental variable method,replacement of explanatory variables and other methods to test its endogeneity and stability,the results remain robust.In terms of regional heterogeneity,the impact of digital economic development on carbon productivity is less pronounced in the central and western regions compared to the eastern region.Additionally,further investigation reveals that industrial structure upgrading and science and technology investment level exhibit different threshold effects on the influence of digital economy development level on carbon productivity.Moreover,there is a significant spatial spillover effect of digital economy development on carbon productivity with H-H and L-L agglomeration spatial correlation.
基金National Social Science Foundation of China, No. 11BJY063 Program for New Century Excellent Talents in University, No.NECT-13-0844
文摘Based on provincial panel data of water footprint and grey water footprint, and with the help of data envelopment analysis model considering and without considering the unde- sirable output, this paper estimates the water resources utilization efficiency in China from 1997 to 2011. The spatial weighting matrix based on economy-spatial distance function is established to discuss spatial autocorrelation of water resources utilization efficiency. With the help of absolute/3-convergence model, this paper concludes that there exists/%convergence in the water resources utilization efficiency. Under the conditions of considering and without considering the undesirable output, it takes about 52.6 and 5.6 years respectively to achieve the extent of half of convergence. By mean of the spatial Durbin econometric model, this paper studies spatial spillover effects of the provincial water resources utilization efficiency in China. The results are as follows. 1） With considering and without considering the undesir- able output, there is significant spatial correlation in provincial water resource efficiency in China. 2） Under the two cases, the spatial autoregressive coefficients （p） are 0.278 and 0.507 respectively, at 1% significance level. There exist the spatial spillover effects of provin- cial water resources utilization efficiency. 3） With considering the undesirable output, these factors of the education funds, the transportation infrastructure, and the industrial and agri- cultural water consumption proportion have positive impacts. These factors of foreign direct investment, the industry value-added water consumption per ten thousand yuan, per capita water consumption, and the total precipitation have negative impacts. 4） Without considering the undesirable output, the factor of GDP per laborer has a greater positive significant influ- ence on the water resources utilization efficiency. However the facts of industry value-added water consumption in ten thousand yuan and the transportation infrastructure have no sig- nificant influence. 5） Regardless of undesirable output of water resources utilization efficiency the assessment of the present real water resources utilization in China will be distorted and policy-making will be misled. The water efficiency measure considering environmental factors （such as gray water footprint） is more reasonable.
基金supported by the National Natural Science Foundation of China(No.42071211)。
文摘As an organic part of urban functions, industrial land is of great significance to the urban healthy and sustainable development. Although consensus has been reached on the evolutionary characteristics and spatial effects of industrial land, the influence mechanism of the evolution of industrial land on urban space still needs further exploration. Therefore, the evolution of industrial land in Xi’an from 2003 to 2019 is analyzed by the land use change matrixes, mixed degrees index, and sprawl index according to the multisource data. The results show that the scale change of industrial land is characterized by an inverted U-shaped curve and development zone-oriented spatial aggregation. Suburbanization, the conversion of agricultural land to industrial land in the suburbs, has intensified urban sprawl, resulting in more serious work-living imbalance and traffic congestion.Deindustrialization, the conversion of industrial land to residential, commercial, and business facilities land in the city center, has promoted urban sprawl, generated a large amount of construction waste, and caused a waste of resources. Based on the complex factors such as urban planning, land finance, and development zones, this study contributes to the research of the improvement of the rationality of urban land layout by revealing the influence mechanism of the evolution of industrial land on urban space.
文摘In recent decades, Urban Heat Island Effects have become more pronounced and more widely examined. Despite great technological advances, our current societies still experience great spatial disparity in urban forest access. Urban Heat Island Effects are measurable phenomenon that are being experienced by the world’s most urbanized areas, including increased summer high temperatures and lower evapotranspiration from having impervious surfaces instead of vegetation and trees. Tree canopy cover is our natural mitigation tool that absorbs sunlight for photosynthesis, protects humans from incoming radiation, and releases cooling moisture into the air. Unfortunately, urban areas typically have low levels of vegetation. Vulnerable urban communities are lower-income areas of inner cities with less access to heat protection like air conditioners. This study uses mean evapotranspiration levels to assess the variability of urban heat island effects across the state of Tennessee. Results show that increased developed land surface cover in Tennessee creates measurable changes in atmospheric evapotranspiration. As a result, the mean evapotranspiration levels in areas with less tree vegetation are significantly lower than the surrounding forested areas. Central areas of urban cities in Tennessee had lower mean evapotranspiration recordings than surrounding areas with less development. This work demonstrates the need for increased tree canopy coverage.
基金The National Key Technology R&D Program of China during the 11 th Five-Year Plan Period(No.2006BAH02A06)Program for New Century Excellent Talents in China(No.NCET-05-0529)
文摘Spatial spillover effects,either positive or negative,of transport infrastructure,highways/expressways,etc.,on regional economic growth are proposed.Using the panel data for 11 cities of Zhejiang province from 1994 to 2003,a spatial production function is applied to examine the spatial spillovers which can be generated as a positive output spillover from the transport infrastructure between neighboring cities.Some spatial weighted matrices are adopted to define different neighboring cities to measure how easily factors or economic activities can migrate between regions.The estimation results show that the output elasticity of the highway infrastructure in 11 cities are all insignificant at a 5% significance level;hence,highway infrastructure in a region cannot explain the same region's economic growth.On the other hand,the highway infrastructure of other contiguous regions has positive spillover effects on a same region's economic growth.
基金This work was partially supported by the National Natural Science Foundation of China(51773060,and 52073091)Shanghai Natural Science Foundation(20ZR1414600)+1 种基金Shanghai Aerospace Science and Technology Innovation Fund(SAST2020-087)the Fundamental Research Funds for the Central Universities(50321042017001).
文摘To explore the influence of substituent groups on thermally induced curing,eight new bio-based benzoxazines containing different substituent groups with different electron negativity and volumes were synthesized.The thermal curing of these bio-based benzoxazines was studied in detail.Combined with the curing reaction kinetics,simulation and calculation of Highest Occupied Molecular and Lowest Unoccupied Molecular values,the spatial and electronic effects of different substituent groups on the curing of benzoxazine was explored.It was found that when the substituent was located at the position directly connected to the N atom,the steric hindrance effect of the group was dominant.When the substituent group was located on the benzene ring connected to the O atom,both the electronic effect and the spatial effect influenced the curing of benzoxazine.When an electron-withdrawing group was connected ortho position to the O atom,the curing reaction was promoted due to the decreased electron cloud density of O-on the oxazine ring,making the C-O bond easier to break.When an electron-donating group was connected to the meta position of the O atom it also promoted the curing reaction,possibly because it increased the electron cloud density of the+CH2 reaction site and thereby facilitated electrophilic substitution via attack of+CH2 on the cross linking reaction centre.This work provides a deeper understanding of how spatial and electronic effects of substituents affect the curing of benzoxazine.
基金The Strategic Priority Research Program of the Chinese Academy of Sciences,No.XDA23020101National Natural Science Foundation of China,No.41901181。
文摘The Yangtze River Delta(YRD) is a region in China with a serious contradiction between economic growth and environmental pollution. Exploring the spatiotemporal effects and influencing factors of air pollution in the region is highly important for formulating policies to promote the high-quality development of urban industries. This study uses the spatial Durbin model(SDM) to analyze the local direct and spatial spillover effects of industrial transformation on air pollution and quantifies the contribution of each factor. From 2008 to 2018, there was a significant spatial agglomeration of industrial sulfur dioxide emissions(ISDE) in the YRD, and every 1% increase in ISDE led to a synchronous increase of 0.603% in the ISDE in adjacent cities. The industrial scale index(ISCI) and industrial structure index(ISTI), as the core factors of industrial transformation, significantly affect the emissions of sulfur dioxide in the YRD, and the elastic coefficients are 0.677 and-0.368, respectively. The order of the direct effect of the explanatory variables on local ISDE is ISCI>ISTI>foreign direct investment(FDI)>enterprise technological innovation(ETI)>environmental regulation(ER)> per capita GDP(PGDP). Similarly, the order of the spatial spillover effect of all variables on ISDE in adjacent cities is ISCI>PGDP>FDI>ETI>ISTI>ER, and the coefficients of the ISCI and ISTI are 1.531 and 0.113, respectively. This study contributes to the existing research that verifies the environmental Kuznets curve in the YRD, denies the pollution heaven hypothesis, indicates the Porter hypothesis, and provides empirical evidence for the formation mechanism of regional environmental pollution from a spatial spillover perspective.
基金National Natural Science Foundation of China,No.41601151Natural Science Foundation of Guangdong Province,No.2016A030310149Pearl River S&T Nova Program of Guangzhou(201806010187)
文摘In this study, we adopt kernel density estimation, spatial autocorrelation, spatial Markov chain, and panel quantile regression methods to analyze spatial spillover effects and driving factors of carbon emission intensity in 283 Chinese cities from 1992 to 2013. The following results were obtained.(1) Nuclear density estimation shows that the overall average carbon intensity of cities in China has decreased, with differences gradually narrowing.(2) The spatial autocorrelation Moran's I index indicates significant spatial agglomeration of carbon emission intensity is gradually increasing; however, differences between regions have remained stable.(3) Spatial Markov chain analysis shows a Matthew effect in China's urban carbon emission intensity. In addition, low-intensity and high-intensity cities characteristically maintain their initial state during the transition period. Furthermore, there is a clear "Spatial Spillover" effect in urban carbon emission intensity and there is heterogeneity in the spillover effect in different regional contexts; that is, if a city is near a city with low carbon emission intensity, the carbon emission intensity of the first city has a higher probability of upward transfer, and vice versa.(4) Panel quantile results indicate that in cities with low carbon emission intensity, economic growth, technological progress, and appropriate population density play an important role in reducing emissions. In addition, foreign investment intensity and traffic emissions are the main factors that increase carbon emission intensity. In cities with high carbon intensity, population density is an important emission reduction factor, and technological progress has no significant effect. In contrast, industrial emissions, extensive capital investment, and urban land expansion are the main factors driving the increase in carbon intensity.
