The striation plasmas are usually generated within a positive column of glow discharge,where rich and complex physical interactions are involved,especially,in the medium or high pressures.Along these lines,our work ai...The striation plasmas are usually generated within a positive column of glow discharge,where rich and complex physical interactions are involved,especially,in the medium or high pressures.Along these lines,our work aims to thoroughly investigate the formation and destruction of helium striation plasmas at kPa level pressures.The characteristics of the helium striation plasmas,and especially the optical emission properties are explored.The emission lines of 706.52 nm and391.44 nm related to the energetic electrons and the high-energy metastable helium atoms respectively,were focused on in this work.The formation of striation plasmas in a helium glow discharge,is mainly associated with the instability originating from the stepwise ionization of high-energy metastable state atoms,Maxwellization of the electron distribution functions and gas heating.Additionally,the destruction effect of helium striation plasmas is of great significance when a small amount of nitrogen or oxygen is mixed into the discharge plasmas.The reduction of the mean electron energy and the consumption of the high-energy metastable helium atoms are considered as the underlying reasons for the destruction of striation plasmas.展开更多
Eradicating extreme poverty is one of the UN’s primary sustainable development goals(SDG).Arable land is related to eradicating poverty(SDG1)and hunger(SDG2).However,the linkage between arable land use and poverty re...Eradicating extreme poverty is one of the UN’s primary sustainable development goals(SDG).Arable land is related to eradicating poverty(SDG1)and hunger(SDG2).However,the linkage between arable land use and poverty reduction is ambiguous and has seldom been investigated globally.Six indicators of agricultural inputs,crop intensification and extensification were used to explore the relationship between arable land use and poverty.Non-parametric machine learning methods were used to analyze the linkage between agriculture and poverty at the global scale,including the classification and regression tree(CART)and random forest models.We found that the yield gap,fertilizer consumption and potential cropland ratio in protected areas correlated with poverty.Developing countries usually had a ratio of actual to potential yield less than 0.33 and fertilizer consumption less than 7.31 kg/ha.Overall,crop extensification,intensification and agricultural inputs were related to poverty at the global level.展开更多
Urban-rural integration (URI) is a global challenge that is highly related to inequalities, poverty, economic growth, and other Sustainable Development Goals (SDGs). Existing research has evaluated the extent of URI a...Urban-rural integration (URI) is a global challenge that is highly related to inequalities, poverty, economic growth, and other Sustainable Development Goals (SDGs). Existing research has evaluated the extent of URI and explored its influencing factors, but urban-rural linkages are seldom incorporated in evaluation systems, and geographical factors are rarely recognized as the influencing factors. We construct a URI framework including regional economy, rural development, urban-rural linkage, and urban-rural gap. Based on a dataset consisting of 1,669 counties in China in 2020, we reveal the spatial pattern of URI and find a high correlation between the spatial pattern of URI and the relief degree of land surface (RDLS). Using structural equation modeling, we discover that topography has direct ( − 0.18, p < 0.001) and indirect ( − 0.17, p < 0.001) effects on URI. The indirect negative effects are mediated through the infrastructure, and the combination of localized advantages and modern technical conditions could mitigate the negative impact of topography. Finally, we identify 742 counties as lagging regions in URI, which can be clustered into eight types. Our findings could facilitate policy designing for those countries striving for integrated and sustainable development of urban and rural areas.展开更多
Grazing exclusion using fences is a key policy being applied by the Chinese government to rehabilitate degraded grasslands on the Tibetan Plateau(TP)and elsewhere.However,there is a limited understanding of the effect...Grazing exclusion using fences is a key policy being applied by the Chinese government to rehabilitate degraded grasslands on the Tibetan Plateau(TP)and elsewhere.However,there is a limited understanding of the effects of grazing exclusion on alpine ecosystem functions and services and its impacts on herders’livelihoods.Our meta-analyses and questionnaire-based surveys revealed that grazing exclusion with fences was effective in promoting aboveground vegetation growth for up to four years in degraded alpine meadows and for up to eight years in the alpine steppes of the TP.Longer-term fencing did not bring any ecological and economic benefits.We also found that fencing hindered wildlife movement,increased grazing pressure in unfenced areas,lowered the satisfaction of herders,and rendered substantial financial costs to both regional and national governments.We recommend that traditional free grazing should be encouraged if applicable,short-term fencing(for 4-8 years)should be adopted in severely degraded grasslands,and fencing should be avoided in key wildlife habitat areas,especially the protected large mammal species.展开更多
The interactions among industrial development,land use/cover change (LUCC), and environmentaleffects in Changshu in the eastern coastal China wereanalyzed using high-resolution Landsat TM data in 1990,1995, 2000, and ...The interactions among industrial development,land use/cover change (LUCC), and environmentaleffects in Changshu in the eastern coastal China wereanalyzed using high-resolution Landsat TM data in 1990,1995, 2000, and 2006, socio-economic data and waterenvironmental quality monitoring data from researchinstitutes and governmental departments. Three phases ofindustrial development in Changshu were examined (i.e.,the three periods of 1990 to 1995, 1995 to 2000, and 2000to 2006). Besides industrial development and rapidurbanization, land use/cover in Changshu had changeddrastically from 1990 to 2006. This change was characterizedby major replacements of farmland by urban and ruralsettlements, artificial ponds, forested and constructed land.Industrialization, urbanization, agricultural structureadjustment, and rural housing construction were themajor socio-economic driving forces of LUCC inChangshu. In addition, the annual value of ecosystemservices in Changshu decreased slightly during 1990-2000, but increased significantly during 2000-2006.Nevertheless, the local environmental quality in Changshu,especially in rural areas, has not yet been improvedsignificantly. Thus, this paper suggests an increasedattention to fully realize the role of land supply inadjustment of environment-friendly industrial structureand urban-rural spatial restructuring, and translating theland management and environmental protection policiesinto an optimized industrial distribution and land-use pattern.展开更多
基金supported by National Natural Science Foundation of China(No.11875039)。
文摘The striation plasmas are usually generated within a positive column of glow discharge,where rich and complex physical interactions are involved,especially,in the medium or high pressures.Along these lines,our work aims to thoroughly investigate the formation and destruction of helium striation plasmas at kPa level pressures.The characteristics of the helium striation plasmas,and especially the optical emission properties are explored.The emission lines of 706.52 nm and391.44 nm related to the energetic electrons and the high-energy metastable helium atoms respectively,were focused on in this work.The formation of striation plasmas in a helium glow discharge,is mainly associated with the instability originating from the stepwise ionization of high-energy metastable state atoms,Maxwellization of the electron distribution functions and gas heating.Additionally,the destruction effect of helium striation plasmas is of great significance when a small amount of nitrogen or oxygen is mixed into the discharge plasmas.The reduction of the mean electron energy and the consumption of the high-energy metastable helium atoms are considered as the underlying reasons for the destruction of striation plasmas.
基金supported financially by the National Key Research and Development Program(Grant No.2016YFA0600304)the National Natural Science Foundation of China(Grant No.41861144019)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA19030201).
文摘Eradicating extreme poverty is one of the UN’s primary sustainable development goals(SDG).Arable land is related to eradicating poverty(SDG1)and hunger(SDG2).However,the linkage between arable land use and poverty reduction is ambiguous and has seldom been investigated globally.Six indicators of agricultural inputs,crop intensification and extensification were used to explore the relationship between arable land use and poverty.Non-parametric machine learning methods were used to analyze the linkage between agriculture and poverty at the global scale,including the classification and regression tree(CART)and random forest models.We found that the yield gap,fertilizer consumption and potential cropland ratio in protected areas correlated with poverty.Developing countries usually had a ratio of actual to potential yield less than 0.33 and fertilizer consumption less than 7.31 kg/ha.Overall,crop extensification,intensification and agricultural inputs were related to poverty at the global level.
基金the National Natural Science Foundation of China(Grants No.T2261129477 and 41971220)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA23070300).
文摘Urban-rural integration (URI) is a global challenge that is highly related to inequalities, poverty, economic growth, and other Sustainable Development Goals (SDGs). Existing research has evaluated the extent of URI and explored its influencing factors, but urban-rural linkages are seldom incorporated in evaluation systems, and geographical factors are rarely recognized as the influencing factors. We construct a URI framework including regional economy, rural development, urban-rural linkage, and urban-rural gap. Based on a dataset consisting of 1,669 counties in China in 2020, we reveal the spatial pattern of URI and find a high correlation between the spatial pattern of URI and the relief degree of land surface (RDLS). Using structural equation modeling, we discover that topography has direct ( − 0.18, p < 0.001) and indirect ( − 0.17, p < 0.001) effects on URI. The indirect negative effects are mediated through the infrastructure, and the combination of localized advantages and modern technical conditions could mitigate the negative impact of topography. Finally, we identify 742 counties as lagging regions in URI, which can be clustered into eight types. Our findings could facilitate policy designing for those countries striving for integrated and sustainable development of urban and rural areas.
基金supported by the Major Program of the National Natural Science Foundation of China(42293271)the Key Program of the National Natural Science Foundation of China(41931293)the Funded Project of China Postdoctoral Science Foundation(2022M713116).
基金the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0405)the Science and Technology Service Network Initiative(KFJ-STS-QYZD060)+3 种基金the State Key Research Development Program of China(2016YFC0501802,2016YFC0501803 and 2016YFC0502002)the National Natural Science Foundation of China(41871040 and 41501057)the Innovative Research Team of the Ministry of Education of China(IRT_17R59)the Fundamental Research Funds for the Central Universities。
文摘Grazing exclusion using fences is a key policy being applied by the Chinese government to rehabilitate degraded grasslands on the Tibetan Plateau(TP)and elsewhere.However,there is a limited understanding of the effects of grazing exclusion on alpine ecosystem functions and services and its impacts on herders’livelihoods.Our meta-analyses and questionnaire-based surveys revealed that grazing exclusion with fences was effective in promoting aboveground vegetation growth for up to four years in degraded alpine meadows and for up to eight years in the alpine steppes of the TP.Longer-term fencing did not bring any ecological and economic benefits.We also found that fencing hindered wildlife movement,increased grazing pressure in unfenced areas,lowered the satisfaction of herders,and rendered substantial financial costs to both regional and national governments.We recommend that traditional free grazing should be encouraged if applicable,short-term fencing(for 4-8 years)should be adopted in severely degraded grasslands,and fencing should be avoided in key wildlife habitat areas,especially the protected large mammal species.
基金This work was supported by the Knowledge Innovation Program of the Chinese Academy of Sciences(No.KZCX2-YWQN304)the National Natural Science Foundation of China(Grant Nos.40771014 and 40635029)the Ministry of Science and Technology of China(No.2007BAC03A11-01).
文摘The interactions among industrial development,land use/cover change (LUCC), and environmentaleffects in Changshu in the eastern coastal China wereanalyzed using high-resolution Landsat TM data in 1990,1995, 2000, and 2006, socio-economic data and waterenvironmental quality monitoring data from researchinstitutes and governmental departments. Three phases ofindustrial development in Changshu were examined (i.e.,the three periods of 1990 to 1995, 1995 to 2000, and 2000to 2006). Besides industrial development and rapidurbanization, land use/cover in Changshu had changeddrastically from 1990 to 2006. This change was characterizedby major replacements of farmland by urban and ruralsettlements, artificial ponds, forested and constructed land.Industrialization, urbanization, agricultural structureadjustment, and rural housing construction were themajor socio-economic driving forces of LUCC inChangshu. In addition, the annual value of ecosystemservices in Changshu decreased slightly during 1990-2000, but increased significantly during 2000-2006.Nevertheless, the local environmental quality in Changshu,especially in rural areas, has not yet been improvedsignificantly. Thus, this paper suggests an increasedattention to fully realize the role of land supply inadjustment of environment-friendly industrial structureand urban-rural spatial restructuring, and translating theland management and environmental protection policiesinto an optimized industrial distribution and land-use pattern.
