Water pollution is an increasingly serious environmental problem because many pollutants have carcinogenic effects on humans and aquatic organisms.Metal organic framework(MOF),made up of metal ions and multifunctional...Water pollution is an increasingly serious environmental problem because many pollutants have carcinogenic effects on humans and aquatic organisms.Metal organic framework(MOF),made up of metal ions and multifunctional organic ligands,has been one of the most concerned materials because of its adjustable and regular pore structure.MOFs have always shown attractive advantages in membrane separation and adsorption technologies,among which water-stable MOFs are particularly prominent in wastewater treatment(WWT)applications.This review systematically summarizes the application of MOF membranes in membrane filtration,membrane pervaporation and membrane distillation.Also,the adsorption mechanisms of heavy metals,dyes and antibacterials in wastewater have been concluded.In order to tap the full application potential of pristine MOFs in sustainable wastewater treatment,current challenges are discussed in detail and future research directions are proposed.展开更多
Timely response to earthquake characterization can facilitate earthquake emergency rescue and further scientific investigations.On June 1,2022,M_(W) 5.9 earthquake occurred in the southern area of the Longmenshan faul...Timely response to earthquake characterization can facilitate earthquake emergency rescue and further scientific investigations.On June 1,2022,M_(W) 5.9 earthquake occurred in the southern area of the Longmenshan fault zone.This event also happened at the south end of the Dayi seismic gap and is the largest earthquake that has occurred in this seismic gap since the 1970 M 6.2 event.The slip-distribution model constrained by the seismic waveforms suggests a thrust-dominated faulting mechanism.The main slip occurs at a depth of~14 km,and the cumulative energy is released in the first 6 s.The variations of Coulomb stress caused by the mainshock show a positive change in the southwest area of the Dayi seismic gap,indicating possible activation of future earthquakes.In addition,we emphasize the importance of rapid estimation of deformation for near-field hazard delineation,especially when interferometric radar fails to image coseismic deformation in a high relief terrain.展开更多
The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated th...The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated the grid codes which reinforce technical requirements for wind power plants.In this paper,recent grid codes published in different countries have been carefully reviewed.The basic requirements of active power control and reactive power compensation,both of which have particular influence on wind power plants operation,are focused on.Based on this review,it is understood that with the increasing integration of wind energy,there is a worldwide trend to regulate the performance of wind power plants so that they can contribute to the stability and reliability of power system.展开更多
Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites...Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites have been investigated to overcome the defects of single MOF materials to broaden the avenues for the practical applications of MOFs.Among them,MOF-based hybrid nanofiber membranes fabricated by electrospinning combine the advantages of polymer nanofibers and inorganic porous materials,receiving extensive attention and development in energy storage and environmental protection.This review systematically summarizes the recent progress of MOF-based hybrid nanofiber membranes prepared by electrospinning from the perspectives of preparation and application.Firstly,two main methods for preparing MOF/polymer nanofibrous membranes are discussed.Next,the applications of MOF/polymer nanofibrous membranes in energy storage and environmental protection are summarized at length.Finally,to fully tap the potential of MOF-based nanofiber membranes in more fields,the current challenges are proposed,and future research directions are discussed.展开更多
This paper aims to examine the dynamic characteristics of local government debt in the economic cycle and to explore the reasons.Using the provincial panel data from 2002 to 2014 and system GMM,this paper finds that t...This paper aims to examine the dynamic characteristics of local government debt in the economic cycle and to explore the reasons.Using the provincial panel data from 2002 to 2014 and system GMM,this paper finds that the accumulation rate of local debt is characterized by procyclicality.With each additional percentage of the output gap,the implicit debt growth rate may increase by 5.92%and 3.97%respectively during the boom and recession.Even with controlled the market financing environment,this feature is still evident.Further empirical analysis finds that officials’promotion pressure aggravates the pro-cyclical nature of local debt.Local debt is not only an important financing tool for local governments to ease capital constraints and stimulate economic growth,but also threatens economic stability because of its risk attributes.This paper argues that local governments have different emphasis on their goals at different stages of the economic cycle which may be an important reason for the pro-cyclical characteristics of local debts.展开更多
基金supported by the National Natural Science Foundation of China (NSFC-U1904215)Natural Science Foundation of Jiangsu Province (BK20200044)Changjiang scholars program of the Ministry of Education (Q2018270).
文摘Water pollution is an increasingly serious environmental problem because many pollutants have carcinogenic effects on humans and aquatic organisms.Metal organic framework(MOF),made up of metal ions and multifunctional organic ligands,has been one of the most concerned materials because of its adjustable and regular pore structure.MOFs have always shown attractive advantages in membrane separation and adsorption technologies,among which water-stable MOFs are particularly prominent in wastewater treatment(WWT)applications.This review systematically summarizes the application of MOF membranes in membrane filtration,membrane pervaporation and membrane distillation.Also,the adsorption mechanisms of heavy metals,dyes and antibacterials in wastewater have been concluded.In order to tap the full application potential of pristine MOFs in sustainable wastewater treatment,current challenges are discussed in detail and future research directions are proposed.
基金the National Natural Science Foundation of China(No.42174023)。
文摘Timely response to earthquake characterization can facilitate earthquake emergency rescue and further scientific investigations.On June 1,2022,M_(W) 5.9 earthquake occurred in the southern area of the Longmenshan fault zone.This event also happened at the south end of the Dayi seismic gap and is the largest earthquake that has occurred in this seismic gap since the 1970 M 6.2 event.The slip-distribution model constrained by the seismic waveforms suggests a thrust-dominated faulting mechanism.The main slip occurs at a depth of~14 km,and the cumulative energy is released in the first 6 s.The variations of Coulomb stress caused by the mainshock show a positive change in the southwest area of the Dayi seismic gap,indicating possible activation of future earthquakes.In addition,we emphasize the importance of rapid estimation of deformation for near-field hazard delineation,especially when interferometric radar fails to image coseismic deformation in a high relief terrain.
文摘The installation of wind energy has experienced rapid development during recent years.As a result,the operation of power system can be greatly affected.Therefore,the operators of different countries have formulated the grid codes which reinforce technical requirements for wind power plants.In this paper,recent grid codes published in different countries have been carefully reviewed.The basic requirements of active power control and reactive power compensation,both of which have particular influence on wind power plants operation,are focused on.Based on this review,it is understood that with the increasing integration of wind energy,there is a worldwide trend to regulate the performance of wind power plants so that they can contribute to the stability and reliability of power system.
基金This work was supported by the National Natural Science Foundation of China(NSFC-U1904215)Natural Science Foundation of Jiangsu Province(BK20200044)Changjiang scholars program of the Ministry of Education(Q2018270).
文摘Metal–organic frameworks(MOFs)are attractive in many fields due to their unique advantages.However,the practical applications of single MOF materials are limited.In recent years,a large number of MOF-based composites have been investigated to overcome the defects of single MOF materials to broaden the avenues for the practical applications of MOFs.Among them,MOF-based hybrid nanofiber membranes fabricated by electrospinning combine the advantages of polymer nanofibers and inorganic porous materials,receiving extensive attention and development in energy storage and environmental protection.This review systematically summarizes the recent progress of MOF-based hybrid nanofiber membranes prepared by electrospinning from the perspectives of preparation and application.Firstly,two main methods for preparing MOF/polymer nanofibrous membranes are discussed.Next,the applications of MOF/polymer nanofibrous membranes in energy storage and environmental protection are summarized at length.Finally,to fully tap the potential of MOF-based nanofiber membranes in more fields,the current challenges are proposed,and future research directions are discussed.
基金The 61st Batch of China Postdoctoral Science Fund project“Social Cost and Long-term Impact of China’s Industrial Policy:Theory and Empirical Research”(2017M610667)The authors take sole responsibility for the paper。
文摘This paper aims to examine the dynamic characteristics of local government debt in the economic cycle and to explore the reasons.Using the provincial panel data from 2002 to 2014 and system GMM,this paper finds that the accumulation rate of local debt is characterized by procyclicality.With each additional percentage of the output gap,the implicit debt growth rate may increase by 5.92%and 3.97%respectively during the boom and recession.Even with controlled the market financing environment,this feature is still evident.Further empirical analysis finds that officials’promotion pressure aggravates the pro-cyclical nature of local debt.Local debt is not only an important financing tool for local governments to ease capital constraints and stimulate economic growth,but also threatens economic stability because of its risk attributes.This paper argues that local governments have different emphasis on their goals at different stages of the economic cycle which may be an important reason for the pro-cyclical characteristics of local debts.