Virtual power plant(VPP)integrates a variety of distributed renewable energy and energy storage to participate in electricity market transactions,promote the consumption of renewable energy,and improve economic effici...Virtual power plant(VPP)integrates a variety of distributed renewable energy and energy storage to participate in electricity market transactions,promote the consumption of renewable energy,and improve economic efficiency.In this paper,aiming at the uncertainty of distributed wind power and photovoltaic output,considering the coupling relationship between power,carbon trading,and green cardmarket,the optimal operationmodel and bidding scheme of VPP in spot market,carbon trading market,and green card market are established.On this basis,through the Shapley value and independent risk contribution theory in cooperative game theory,the quantitative analysis of the total income and risk contribution of various distributed resources in the virtual power plant is realized.Moreover,the scheduling strategies of virtual power plants under different risk preferences are systematically compared,and the feasibility and accuracy of the combination of Shapley value and independent risk contribution theory in ensuring fair income distribution and reasonable risk assessment are emphasized.A comprehensive solution for virtual power plants in the multi-market environment is constructed,which integrates operation strategy,income distribution mechanism,and risk control system into a unified analysis framework.Through the simulation of multi-scenario examples,the CPLEXsolver inMATLAB software is used to optimize themodel.The proposed joint optimization scheme can increase the profit of VPP participating in carbon trading and green certificate market by 29%.The total revenue of distributed resources managed by VPP is 9%higher than that of individual participation.展开更多
Mineral resources in Asia continent and its mining industry play a significant role in the economic growth and industrialization of both Asia and the world.Asia continent boasts the most comprehensive kinds of mineral...Mineral resources in Asia continent and its mining industry play a significant role in the economic growth and industrialization of both Asia and the world.Asia continent boasts the most comprehensive kinds of minerals,with reserves of at least 38 of over 80 widely used minerals worldwide accounting for more than30%of the global total reserves.Asia continent experienced three main tectonic evolution and mineralization stages:The Precambrian,the Paleozoic,and the Mesozoic to Cenozoic.The abundant mineral resources in this continent can be divided into seven first-order metallogenic belts(metallogenic domains),18 second-order metallogenic belts(metallogenic provinces),61 third-order metallogenic belts(metallogenic zones),and nine main minerogenetic series.Asia continent exhibits the most significant metallogenic specialization among all continents.Specifically,granite belts of Asia continent manifest pronounced metallogenic specialization of tin,rare metals,and porphyry Cu-Au-Mo deposits.Its maficultramafic rock belts and ophiolite belts display notable metallogenic specialization of lateritic nickel deposits and magmatic type chromite deposits,while its Mesozoic to Cenozoic basalt belts show remarkable metallogenic specialization of lateritic bauxite deposits.Consequently,many giant metallogenic belts were formed,including the Southeast Asian tin belt,the Qinghai-Xizang Plateau rare metal metallogenic belt,the Tethyan porphyry Cu-Au-Mo metallogenic belt,the circum-Pacific porphyry Cu-Au-Mo metallogenic belt,the Southeast Asian lateritic bauxite metallogenic belt,the Deccan Plateau lateritic bauxite metallogenic belt in India,the Southeast Asian lateritic nickel metallogenic belt,and the Tethyan magmatic type chromite metallogenic belt—all of which are significant metallogenic belts in Asia continent.Future mineral exploration in Asia should focus primarily on the Precambrian mineralization of ancient cratons,the Paleozoic mineralization of the Central Asian-Mongolian orogenic belt,and the Mesozoic to Cenozoic mineralization of the Tethyan and circum-Pacific mobile belts.Asia's mining industry not only underpins its own economic growth but also propels global economic development and industrialization,contributing significantly to the world economy.Asia boasts the highest production value of minerals,the largest annual production of minerals,and the greatest trade value of mineral products among all the continents,having emerged as the trade center of global mineral products and the center of the mining industry economy.China is identified as one of the few countries that possess the most comprehensive kinds of minerals,and its mining industry has supported and driven the economic development and industrialization of Asia and even the world.Standing as the largest mineral producer worldwide,China ranked first in the production of 28 mineral commodities in the world in 2022.Besides,China exhibits the highest annual production value of minerals and the largest trade value of mineral products among all countries.Therefore,China's demand for global mineral products influences the global supply and demand patterns of minerals and the world economic situation.展开更多
The year 2025 marks the 80th anniversary of the victory of the Chinese People's War of Resistance Against Japanese Aggression and the World Anti-Fascist War.They were a decisive battle between justice and evil,bet...The year 2025 marks the 80th anniversary of the victory of the Chinese People's War of Resistance Against Japanese Aggression and the World Anti-Fascist War.They were a decisive battle between justice and evil,between light and darkness,and between progress and reaction.展开更多
The Changjiang River Estuary(CRE) and its offshore plumes host a diverse phytoplankton community;however, the spatiotemporal dynamics of these microorganisms and their environmental drivers remain poorly understood. T...The Changjiang River Estuary(CRE) and its offshore plumes host a diverse phytoplankton community;however, the spatiotemporal dynamics of these microorganisms and their environmental drivers remain poorly understood. This study aims to elucidate the spatiotemporal variations and environmental heterogeneity of phytoplankton communities in the CRE, as well as to understand the factors driving their assemblage. Utilizing ecological survey data collected from the CRE and adjacent waters during spring and summer from 2018 to 2020, we conducted a spatiotemporal analysis of phytoplankton β-diversity in the region. We decomposed β-diversity into species contributions to β-diversity(SCBD)and local contributions to β-diversity(LCBD) to examine spatial differences in phytoplankton diversity and the contributions of individual species within the community. Our findings reveal that spatial differences, primarily driven by water salinity and distance from the coastline, are key factors influencing the heterogeneity of phytoplankton community composition. Key species such as Skeletonema costatum, Melosira granulata, and M. granulata var.angustissima significantly affected β-diversity. Further, β-diversity decomposition reveals that community assembly is driven by interactive biogeochemical forces: salinity gradients shape spatial heterogeneity through runoff-seawater mixing, eutrophic conditions promote the dominance of nutrient-dependent taxa, and silica availability regulates diatom-to-flagellate succession. This study provides a methodological paradigm for analyzing phytoplankton community assembly mechanisms in estuaries, thereby offering scientific support for biogeography-based ecosystem management in the CRE.展开更多
To overcome the limitations of conventional approaches that adopt monolithic architectures and overlook critical dynamic interactions in evaluating combat effectiveness and subsystem contributions within amphibious op...To overcome the limitations of conventional approaches that adopt monolithic architectures and overlook critical dynamic interactions in evaluating combat effectiveness and subsystem contributions within amphibious operations,this paper proposes an integrated framework combining complex system network modeling with dynamic adversarial simulation for evaluating mission-critical system-of-systems(SoS).Specifically,the contribution rate of unmanned aerial vehicles(UAVs)to the amphibious joint landing SoS(AJLSoS)is quantified.Firstly,a standardized network topology model is developed using operation loop theory,systematically characterizing node functionalities and their interdependencies.Secondly,the ideal Lanchester equation is augmented according to the model’s static operational capability,and an amphibious operational simulation model is constructed based on the modified equation,enabling dynamic simulation of force attrition and engagement duration as key performance indicators of AJLSoS.To validate the theoretical framework,a battalion-level amphibious campaign scenario is developed to compute effectiveness metrics across multiple control scenarios and the contribution rate of UAVs to AJLSoS is analyzed.This study not only provides actionable insights for operational mission planning of UAVs in the context of amphibious operations but also demonstrates high adaptability to diverse operational contexts.展开更多
During high-temperature periods in summer,formaldehyde(HCHO)levels increase due to secondary production.However,recent studies have also shown a rise in the HCHO concentration in winter,but the underlying cause remain...During high-temperature periods in summer,formaldehyde(HCHO)levels increase due to secondary production.However,recent studies have also shown a rise in the HCHO concentration in winter,but the underlying cause remains unclear.Here,HCHO observations in urban Beijing were conducted,the impact of meteorological differences between warm and cold seasons to HCHO concentrations was investigated.Additionally,the positive matrix factorization model was applied to the source apportionment of HCHO,with a focus on changes during pollution events.The results indicated that,during warm seasons,the secondary production of HCHO was driven by high temperature influenced by the low-pressure front,with the contribution of secondary production+background peaking at 85.9% in the afternoon,exhibiting a unimodal diurnal variation.Conversely,during cold seasons,the influence of a uniform pressure field,coupled with weak winds,low boundary layers and high humidity,led to HCHO accumulation from primary emissions,resulting in multiday highconcentration pollution.During the most severe pollution periods,anthropogenic primary emissions contributed up to 91.7%.Therefore,while the contribution of volatile organic compounds to HCHO levels through secondary production has been recognized,the significant impact of primary emissions during cold seasons cannot be overlooked.展开更多
China is the world's largest carbon dioxide(CO_(2)) emitter and a major trading country. Both anthropogenic and natural factors play a critical role in its carbon budget. However,previous studies mostly focus on e...China is the world's largest carbon dioxide(CO_(2)) emitter and a major trading country. Both anthropogenic and natural factors play a critical role in its carbon budget. However,previous studies mostly focus on evaluating anthropogenic emissions or the natural carbon cycle separately, and few included trade-related(import and export) CO_(2) emissions and its contribution on global warming. Using the Carbon Tracker CT2019 assimilation dataset and China trade emissions from the Global Carbon Project, we found that the change trend of global CO_(2) flux had obvious spatial heterogeneity, which is mainly affected by anthropogenic CO_(2) flux. From 2000 to 2018, carbon emissions from fossil fuels in the world and in China all showed an obvious increasing trend, but the magnitude of the increase tended to slow down.In 2018, the radiative forcing(RF) caused by China's import and export trade was-0.0038 W m^(-2), and the RF caused by natural carbon budget was-0.0027 W m^(-2), offsetting 1.54% and 1.13% of the RF caused by fossil fuels that year, respectively. From 2000 to 2018, the contribution of China's carbon emission from fossil fuels to global RF was 11.32%. Considering China's import and export trade, the contribution of anthropogenic CO_(2) emission to global RF decreased to 9.50%. Furthermore, taking into account the offset of carbon sink from China's terrestrial ecosystems, the net contribution of China to global RF decreased to 7.63%. This study demonstrates that China's terrestrial ecosystem and import and export trade are all mitigating China's impact on global anthropogenic warming, and also confirms that during the research process on climate change, comprehensively considering the carbon budget from anthropogenic and natural carbon budgets is necessary to systematically understand the impacts of regional or national carbon budgets on global warming.展开更多
The purpose of this paper is to identify the processes with the highest contribution to potential environmental impacts in the life cycle of the masonry of concrete blocks by evaluating their main emissions contributi...The purpose of this paper is to identify the processes with the highest contribution to potential environmental impacts in the life cycle of the masonry of concrete blocks by evaluating their main emissions contributing to impact categories and identifying hotspots for environmental improvements.The research is based on the Life Cycle Assessment(LCA)study of non-load-bearing masonry of concrete blocks performed by the authors.The processes those have demonstrated higher contribution to environmental impacts were identified in the Life Cycle Impact Assessment(LCIA)phase and a detailed analysis was carried out on the main substances derived from these processes.The highest potential impacts in the life cycle of the concrete blocks masonry can be attributed mainly to emissions coming from the production of Portland cement,which explains the peak of impact potential on the blocks production stage,but also the significant impact potential in the use of the blocks for masonry construction,due to the use of cement mortar.The results of this LCA study are part of a major research on the comparative analysis of different typologies of non-load-bearing external walls,which aims to contribute to the creation of a life cycle database of major building systems,to be used by the environmental certification systems of buildings.展开更多
CO_(2) emissions(CEs)pose a growing threat to environmental changes and global warming,attracting extensive attention.Here,we leveraged near-real-time monitoring data spanning 2019 to 2022 to investigate spatiotempora...CO_(2) emissions(CEs)pose a growing threat to environmental changes and global warming,attracting extensive attention.Here,we leveraged near-real-time monitoring data spanning 2019 to 2022 to investigate spatiotemporal heterogeneity,sectoral contributions,provincial spatial correlation,and driving factors influencing CEs at the provincial level in China.Our analysis,integrating Moran’s Index analysis,Spearman correlation analysis,and the Geographically Weighted Regression model,unveiled China’s consistent world-leading CEs,surpassing 10,000 Mt over the study period.Spatially,CEs exhibited a heterogeneous distribution,with markedly higher emissions in eastern and northern regions compared to western and southern areas.Temporally,CEs displayed significant fluctuations,peaking in the fourth quarter before declining in subsequent quarters.Chinese NewYear and COVID-19 had the biggest effects on CEs,with average daily reductions of-20.8%and-18.9%,respectively,compared to the four-year average and the same period in 2019.Sectoral analysis highlighted the power and industry sectors as primary contributors to CEs in China,jointly accounting for 37.9%-40.2%and 43.5%-46.4%of total CEs,respectively.Spatial clustering analysis identified a distinct High-High agglomeration region,predominantly encompassing provinces such as Inner Mongolia,Shandong and Jiangsu.Furthermore,total energy consumption and electricity consumption emerged as significant drivers of CEs,exhibiting correlation coefficients exceeding 0.9,followed by exhaust emissions,population size,and gross domestic product.Moreover,the influence of drivers on provincial CEs exhibited notable spatial heterogeneity,with regression coefficients displaying a decreasing gradient from north to south.These findings provide scientific and technological support to realize the provincial dual-carbon goals in China.展开更多
A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the ...A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.展开更多
The impacts of elevated atmospheric CO2 concentrations (500 靘olmol-1and 700 靘olmol-1) on total soil respiration and the contribution of root respiration of Pinus koraiensis seedlings were investigated from May to Oc...The impacts of elevated atmospheric CO2 concentrations (500 靘olmol-1and 700 靘olmol-1) on total soil respiration and the contribution of root respiration of Pinus koraiensis seedlings were investigated from May to October in 2003 at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, Jilin Province, China. After four growing seasons in top-open chambers exposed to elevated CO2, the total soil respiration and roots respiration of Pinus koraiensis seedlings were measured by a LI-6400-09 soil CO2 flux chamber. Three PVC cylinders in each chamber were inserted about 30 cm into the soil in-stantaneously to terminate the supply of current photosynthates from the tree canopy to roots for separating the root respiration from total soil respiration. Soil respirations both inside and outside of the cylinders were measured on June 16, August 20 and October 8, respectively. The results indicated that: there was a marked diurnal change in air temperature and soil temperature at depth of 5 cm on June 16, the maximum of soil temperature at depth of 5 cm lagged behind that of air temperature, no differences in temperature between treatments were found (P>0.05). The total soil respiration and soil respiration with roots severed showed strong diurnal and seasonal patterns. There was marked difference in total soil respiration and soil respiration with roots severed between treatments (P<0.01); Mean total soil respiration and contribution of root under different treatments were 3.26, 4.78 and 1.47 靘olm 2s-1, 11.5%, 43.1% and 27.9% on June 16, August 20 and October 8, respectively.展开更多
[Objective] The aim was to investigate the contribution of potassium,nitrogen and organic fertilizer to super rice production.[Method] The data about the labor force input,fertilizer input,organic fertilizer input,con...[Objective] The aim was to investigate the contribution of potassium,nitrogen and organic fertilizer to super rice production.[Method] The data about the labor force input,fertilizer input,organic fertilizer input,contents of effective nitrogen and effective potassium in production,obtained through empirical study of 690 rice farmers in eight counties （cities） in Liaoning,Zhejiang and Hunan in 2009,were analyzed by using Cobb-Douglas production function model to study influence of material input （especially the fertilizer input） and labor force input to the yield of super rice,and the correlation between the input and the yield of rice production.[Result] The increase in amount of organic fertilizer has significantly increased the yield of super rice.The amount of chemical fertilizer applied is becoming more reasonable,but increase of yield does not result in increase of value.Different types of fertilizers have significantly different capabilities in increasing yields of super rice.The potassium fertilizer is superior to phosphorous fertilizer,while phosphorous is superior to nitrogenous fertilizer in improving production capacity.[Conclusion] The paper suggests that it should continue to increase the amount of organic fertilizers and potassium fertilizer and meanwhile control the amount of nitrogenous fertilizer in super rice production at present.展开更多
基金funded by the Department of Education of Liaoning Province and was supported by the Basic Scientific Research Project of the Department of Education of Liaoning Province(Grant No.LJ222411632051)and(Grant No.LJKQZ2021085)Natural Science Foundation Project of Liaoning Province(Grant No.2022-BS-222).
文摘Virtual power plant(VPP)integrates a variety of distributed renewable energy and energy storage to participate in electricity market transactions,promote the consumption of renewable energy,and improve economic efficiency.In this paper,aiming at the uncertainty of distributed wind power and photovoltaic output,considering the coupling relationship between power,carbon trading,and green cardmarket,the optimal operationmodel and bidding scheme of VPP in spot market,carbon trading market,and green card market are established.On this basis,through the Shapley value and independent risk contribution theory in cooperative game theory,the quantitative analysis of the total income and risk contribution of various distributed resources in the virtual power plant is realized.Moreover,the scheduling strategies of virtual power plants under different risk preferences are systematically compared,and the feasibility and accuracy of the combination of Shapley value and independent risk contribution theory in ensuring fair income distribution and reasonable risk assessment are emphasized.A comprehensive solution for virtual power plants in the multi-market environment is constructed,which integrates operation strategy,income distribution mechanism,and risk control system into a unified analysis framework.Through the simulation of multi-scenario examples,the CPLEXsolver inMATLAB software is used to optimize themodel.The proposed joint optimization scheme can increase the profit of VPP participating in carbon trading and green certificate market by 29%.The total revenue of distributed resources managed by VPP is 9%higher than that of individual participation.
基金funded by geological survey project of China Geological Survey(DD20211404)。
文摘Mineral resources in Asia continent and its mining industry play a significant role in the economic growth and industrialization of both Asia and the world.Asia continent boasts the most comprehensive kinds of minerals,with reserves of at least 38 of over 80 widely used minerals worldwide accounting for more than30%of the global total reserves.Asia continent experienced three main tectonic evolution and mineralization stages:The Precambrian,the Paleozoic,and the Mesozoic to Cenozoic.The abundant mineral resources in this continent can be divided into seven first-order metallogenic belts(metallogenic domains),18 second-order metallogenic belts(metallogenic provinces),61 third-order metallogenic belts(metallogenic zones),and nine main minerogenetic series.Asia continent exhibits the most significant metallogenic specialization among all continents.Specifically,granite belts of Asia continent manifest pronounced metallogenic specialization of tin,rare metals,and porphyry Cu-Au-Mo deposits.Its maficultramafic rock belts and ophiolite belts display notable metallogenic specialization of lateritic nickel deposits and magmatic type chromite deposits,while its Mesozoic to Cenozoic basalt belts show remarkable metallogenic specialization of lateritic bauxite deposits.Consequently,many giant metallogenic belts were formed,including the Southeast Asian tin belt,the Qinghai-Xizang Plateau rare metal metallogenic belt,the Tethyan porphyry Cu-Au-Mo metallogenic belt,the circum-Pacific porphyry Cu-Au-Mo metallogenic belt,the Southeast Asian lateritic bauxite metallogenic belt,the Deccan Plateau lateritic bauxite metallogenic belt in India,the Southeast Asian lateritic nickel metallogenic belt,and the Tethyan magmatic type chromite metallogenic belt—all of which are significant metallogenic belts in Asia continent.Future mineral exploration in Asia should focus primarily on the Precambrian mineralization of ancient cratons,the Paleozoic mineralization of the Central Asian-Mongolian orogenic belt,and the Mesozoic to Cenozoic mineralization of the Tethyan and circum-Pacific mobile belts.Asia's mining industry not only underpins its own economic growth but also propels global economic development and industrialization,contributing significantly to the world economy.Asia boasts the highest production value of minerals,the largest annual production of minerals,and the greatest trade value of mineral products among all the continents,having emerged as the trade center of global mineral products and the center of the mining industry economy.China is identified as one of the few countries that possess the most comprehensive kinds of minerals,and its mining industry has supported and driven the economic development and industrialization of Asia and even the world.Standing as the largest mineral producer worldwide,China ranked first in the production of 28 mineral commodities in the world in 2022.Besides,China exhibits the highest annual production value of minerals and the largest trade value of mineral products among all countries.Therefore,China's demand for global mineral products influences the global supply and demand patterns of minerals and the world economic situation.
文摘The year 2025 marks the 80th anniversary of the victory of the Chinese People's War of Resistance Against Japanese Aggression and the World Anti-Fascist War.They were a decisive battle between justice and evil,between light and darkness,and between progress and reaction.
基金The program of opening ceremony to select the best candidates of the Key Laboratory of Marine Ecological Monitoring and Restoration Technologies,MNR under contract No. MEMRT2024JBGS01。
文摘The Changjiang River Estuary(CRE) and its offshore plumes host a diverse phytoplankton community;however, the spatiotemporal dynamics of these microorganisms and their environmental drivers remain poorly understood. This study aims to elucidate the spatiotemporal variations and environmental heterogeneity of phytoplankton communities in the CRE, as well as to understand the factors driving their assemblage. Utilizing ecological survey data collected from the CRE and adjacent waters during spring and summer from 2018 to 2020, we conducted a spatiotemporal analysis of phytoplankton β-diversity in the region. We decomposed β-diversity into species contributions to β-diversity(SCBD)and local contributions to β-diversity(LCBD) to examine spatial differences in phytoplankton diversity and the contributions of individual species within the community. Our findings reveal that spatial differences, primarily driven by water salinity and distance from the coastline, are key factors influencing the heterogeneity of phytoplankton community composition. Key species such as Skeletonema costatum, Melosira granulata, and M. granulata var.angustissima significantly affected β-diversity. Further, β-diversity decomposition reveals that community assembly is driven by interactive biogeochemical forces: salinity gradients shape spatial heterogeneity through runoff-seawater mixing, eutrophic conditions promote the dominance of nutrient-dependent taxa, and silica availability regulates diatom-to-flagellate succession. This study provides a methodological paradigm for analyzing phytoplankton community assembly mechanisms in estuaries, thereby offering scientific support for biogeography-based ecosystem management in the CRE.
文摘To overcome the limitations of conventional approaches that adopt monolithic architectures and overlook critical dynamic interactions in evaluating combat effectiveness and subsystem contributions within amphibious operations,this paper proposes an integrated framework combining complex system network modeling with dynamic adversarial simulation for evaluating mission-critical system-of-systems(SoS).Specifically,the contribution rate of unmanned aerial vehicles(UAVs)to the amphibious joint landing SoS(AJLSoS)is quantified.Firstly,a standardized network topology model is developed using operation loop theory,systematically characterizing node functionalities and their interdependencies.Secondly,the ideal Lanchester equation is augmented according to the model’s static operational capability,and an amphibious operational simulation model is constructed based on the modified equation,enabling dynamic simulation of force attrition and engagement duration as key performance indicators of AJLSoS.To validate the theoretical framework,a battalion-level amphibious campaign scenario is developed to compute effectiveness metrics across multiple control scenarios and the contribution rate of UAVs to AJLSoS is analyzed.This study not only provides actionable insights for operational mission planning of UAVs in the context of amphibious operations but also demonstrates high adaptability to diverse operational contexts.
基金supported by the National Natural Science Foundation of China(Nos.42075097 and 42177081)the National Key R&D Program of China(No.2023YFC3706103)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0760200)Beijing Municipal Natural Science Foundation(No.8222075)the Youth Cross Team Scientific Research Project of the Chinese Academy of Sciences(No.JCTD-2021-10)。
文摘During high-temperature periods in summer,formaldehyde(HCHO)levels increase due to secondary production.However,recent studies have also shown a rise in the HCHO concentration in winter,but the underlying cause remains unclear.Here,HCHO observations in urban Beijing were conducted,the impact of meteorological differences between warm and cold seasons to HCHO concentrations was investigated.Additionally,the positive matrix factorization model was applied to the source apportionment of HCHO,with a focus on changes during pollution events.The results indicated that,during warm seasons,the secondary production of HCHO was driven by high temperature influenced by the low-pressure front,with the contribution of secondary production+background peaking at 85.9% in the afternoon,exhibiting a unimodal diurnal variation.Conversely,during cold seasons,the influence of a uniform pressure field,coupled with weak winds,low boundary layers and high humidity,led to HCHO accumulation from primary emissions,resulting in multiday highconcentration pollution.During the most severe pollution periods,anthropogenic primary emissions contributed up to 91.7%.Therefore,while the contribution of volatile organic compounds to HCHO levels through secondary production has been recognized,the significant impact of primary emissions during cold seasons cannot be overlooked.
基金National Natural Science Foundation of China,No.42071415National Key Research and Development Program of China,No.2021YFE0106700Outstanding Youth Foundation of Henan Natural Science Foundation,No.202300410049。
文摘China is the world's largest carbon dioxide(CO_(2)) emitter and a major trading country. Both anthropogenic and natural factors play a critical role in its carbon budget. However,previous studies mostly focus on evaluating anthropogenic emissions or the natural carbon cycle separately, and few included trade-related(import and export) CO_(2) emissions and its contribution on global warming. Using the Carbon Tracker CT2019 assimilation dataset and China trade emissions from the Global Carbon Project, we found that the change trend of global CO_(2) flux had obvious spatial heterogeneity, which is mainly affected by anthropogenic CO_(2) flux. From 2000 to 2018, carbon emissions from fossil fuels in the world and in China all showed an obvious increasing trend, but the magnitude of the increase tended to slow down.In 2018, the radiative forcing(RF) caused by China's import and export trade was-0.0038 W m^(-2), and the RF caused by natural carbon budget was-0.0027 W m^(-2), offsetting 1.54% and 1.13% of the RF caused by fossil fuels that year, respectively. From 2000 to 2018, the contribution of China's carbon emission from fossil fuels to global RF was 11.32%. Considering China's import and export trade, the contribution of anthropogenic CO_(2) emission to global RF decreased to 9.50%. Furthermore, taking into account the offset of carbon sink from China's terrestrial ecosystems, the net contribution of China to global RF decreased to 7.63%. This study demonstrates that China's terrestrial ecosystem and import and export trade are all mitigating China's impact on global anthropogenic warming, and also confirms that during the research process on climate change, comprehensively considering the carbon budget from anthropogenic and natural carbon budgets is necessary to systematically understand the impacts of regional or national carbon budgets on global warming.
基金The authors would like to acknowledge CAPES (Higher Education Personnel Improvement Coordination) for the financial support given to this research.
文摘The purpose of this paper is to identify the processes with the highest contribution to potential environmental impacts in the life cycle of the masonry of concrete blocks by evaluating their main emissions contributing to impact categories and identifying hotspots for environmental improvements.The research is based on the Life Cycle Assessment(LCA)study of non-load-bearing masonry of concrete blocks performed by the authors.The processes those have demonstrated higher contribution to environmental impacts were identified in the Life Cycle Impact Assessment(LCIA)phase and a detailed analysis was carried out on the main substances derived from these processes.The highest potential impacts in the life cycle of the concrete blocks masonry can be attributed mainly to emissions coming from the production of Portland cement,which explains the peak of impact potential on the blocks production stage,but also the significant impact potential in the use of the blocks for masonry construction,due to the use of cement mortar.The results of this LCA study are part of a major research on the comparative analysis of different typologies of non-load-bearing external walls,which aims to contribute to the creation of a life cycle database of major building systems,to be used by the environmental certification systems of buildings.
基金supported by the National Natural Science Foundation of China(No.52200120)the R&D Program of Beijing Municipal Education Commission(No.KM202310011003).
文摘CO_(2) emissions(CEs)pose a growing threat to environmental changes and global warming,attracting extensive attention.Here,we leveraged near-real-time monitoring data spanning 2019 to 2022 to investigate spatiotemporal heterogeneity,sectoral contributions,provincial spatial correlation,and driving factors influencing CEs at the provincial level in China.Our analysis,integrating Moran’s Index analysis,Spearman correlation analysis,and the Geographically Weighted Regression model,unveiled China’s consistent world-leading CEs,surpassing 10,000 Mt over the study period.Spatially,CEs exhibited a heterogeneous distribution,with markedly higher emissions in eastern and northern regions compared to western and southern areas.Temporally,CEs displayed significant fluctuations,peaking in the fourth quarter before declining in subsequent quarters.Chinese NewYear and COVID-19 had the biggest effects on CEs,with average daily reductions of-20.8%and-18.9%,respectively,compared to the four-year average and the same period in 2019.Sectoral analysis highlighted the power and industry sectors as primary contributors to CEs in China,jointly accounting for 37.9%-40.2%and 43.5%-46.4%of total CEs,respectively.Spatial clustering analysis identified a distinct High-High agglomeration region,predominantly encompassing provinces such as Inner Mongolia,Shandong and Jiangsu.Furthermore,total energy consumption and electricity consumption emerged as significant drivers of CEs,exhibiting correlation coefficients exceeding 0.9,followed by exhaust emissions,population size,and gross domestic product.Moreover,the influence of drivers on provincial CEs exhibited notable spatial heterogeneity,with regression coefficients displaying a decreasing gradient from north to south.These findings provide scientific and technological support to realize the provincial dual-carbon goals in China.
文摘A finite element and boundary element model of the 100 m X-BOW polar exploration cruise ship is established. The vibrated velocity-excited force admittance matrix is calculated by frequency response analysis, and the vibrated velocity in the stern plate and main engine foundations is tested during the trial trip. Then, the excited force of the propeller and main engine is derived using the vibrated velocity and admittance matrix.Based on the excited force, the cabin-simulated vibrated velocity is compared with the tested vibrated velocity, and the tolerance is within the allowable scope in engineering. Loading the excited forces on the boundary element model, the distribution characteristics of sound level underwater are analyzed. Then, forces excited by the main engine and propeller are loaded on the model, and the contribution ratio of excitation sources to underwater acoustic radiation is analyzed. The result provides a reference for vibration assessment in the early stage and control in the late stage.
文摘The impacts of elevated atmospheric CO2 concentrations (500 靘olmol-1and 700 靘olmol-1) on total soil respiration and the contribution of root respiration of Pinus koraiensis seedlings were investigated from May to October in 2003 at the Research Station of Changbai Mountain Forest Ecosystems, Chinese Academy of Sciences, Jilin Province, China. After four growing seasons in top-open chambers exposed to elevated CO2, the total soil respiration and roots respiration of Pinus koraiensis seedlings were measured by a LI-6400-09 soil CO2 flux chamber. Three PVC cylinders in each chamber were inserted about 30 cm into the soil in-stantaneously to terminate the supply of current photosynthates from the tree canopy to roots for separating the root respiration from total soil respiration. Soil respirations both inside and outside of the cylinders were measured on June 16, August 20 and October 8, respectively. The results indicated that: there was a marked diurnal change in air temperature and soil temperature at depth of 5 cm on June 16, the maximum of soil temperature at depth of 5 cm lagged behind that of air temperature, no differences in temperature between treatments were found (P>0.05). The total soil respiration and soil respiration with roots severed showed strong diurnal and seasonal patterns. There was marked difference in total soil respiration and soil respiration with roots severed between treatments (P<0.01); Mean total soil respiration and contribution of root under different treatments were 3.26, 4.78 and 1.47 靘olm 2s-1, 11.5%, 43.1% and 27.9% on June 16, August 20 and October 8, respectively.
文摘[Objective] The aim was to investigate the contribution of potassium,nitrogen and organic fertilizer to super rice production.[Method] The data about the labor force input,fertilizer input,organic fertilizer input,contents of effective nitrogen and effective potassium in production,obtained through empirical study of 690 rice farmers in eight counties （cities） in Liaoning,Zhejiang and Hunan in 2009,were analyzed by using Cobb-Douglas production function model to study influence of material input （especially the fertilizer input） and labor force input to the yield of super rice,and the correlation between the input and the yield of rice production.[Result] The increase in amount of organic fertilizer has significantly increased the yield of super rice.The amount of chemical fertilizer applied is becoming more reasonable,but increase of yield does not result in increase of value.Different types of fertilizers have significantly different capabilities in increasing yields of super rice.The potassium fertilizer is superior to phosphorous fertilizer,while phosphorous is superior to nitrogenous fertilizer in improving production capacity.[Conclusion] The paper suggests that it should continue to increase the amount of organic fertilizers and potassium fertilizer and meanwhile control the amount of nitrogenous fertilizer in super rice production at present.
