A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structu...A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structure,optical,and photocatalytic properties of the composite were characterized.The results showed that the composite had a sheet flower-like structure with a large specific surface area.Ultraviolet-visible diffuse reflection spectra and photoluminescence spectra showed that the composite had an excellent visible-light response and a low recombination rate of photoinduced electron hole pairs.The photocatalytic property of the composite was evaluated by the removal efficiency of rhodamine B and ciprofloxacin under visible-light illumination.The composite’s reaction rate constant of removing rhodamine B(/ciprofloxacin)was approximately 8.14(/4.94),42.63(/11.91)and 64.66(/36.07)times that of Bi12O17Cl2,P25,and BiOCl,respectively.Furthermore,the composite showed a wide applicable pH range and excellent reusability.Mechanism analysis showed that photogenerated holes played a dominant role and·O2–also contributed to photocatalytic degradation.In summary,this study presents a high-efficiency photocatalyst for wastewater treatment.展开更多
Reasonable income distribution and eradication of rural poverty are vital for building a moderately prosperous society in all respects in China.This paper primarily examines the income distribution and poverty reducti...Reasonable income distribution and eradication of rural poverty are vital for building a moderately prosperous society in all respects in China.This paper primarily examines the income distribution and poverty reduction effects of social security spending.Market income and redistribution policies are two determinants of income gaps.Based on CHIP2018 household survey data,we find that inadequate income redistribution policies have contributed to yawning income gaps,and that social security spending is more redistributive than personal income tax and social security contributions.After estimating the redistribution effects of social security spending and itemized incomes,we find that pension payments have contributed the most to household income gaps,and that subsistence protection and rural pension payments help improve income distribution.With respect to the poverty reduction effects of social security spending,we have estimated China’s current poverty incidence and the poverty reduction effects of pension payments,healthcare,and educational allowances with CHIP2018 data,and discover that an increase in social security spending may effectively reduce rural poverty.In building a moderately prosperous society in all respects,China should increase social security spending,focusing on specific target groups,and promote the role of social security spending in regulating income distribution and offering social protection to rural residents.展开更多
The time period between 2020 and 2035 is vital for China to achieve its second centennial goal.During this period,China must avoid the middle-income trap and achieve socialist modernization.To accomplish this goal,Chi...The time period between 2020 and 2035 is vital for China to achieve its second centennial goal.During this period,China must avoid the middle-income trap and achieve socialist modernization.To accomplish this goal,China must maintain a certain pace of economic growth and strive to double its real GDP per capita by 2035.However,by the current growth trajectory,China’s average economic growth rate is expected to stay at approximately 3.8%over the period between 2020-2035.This makes the GDP per capita growth target hard to achieve.Even when in a high-quality development stage,China should speed up economic growth while enhancing growth quality.Speed and quality are interdependent rather than contradictory with each other.To ramp up economic growth potentials,China must proceed with market-oriented reforms and shift economic growth drivers.To improve economic growth quality,household consumption should be increased to unleash China’s full potential,not only as the factory floor of the world but also one of world’s biggest markets,i.e.“dual circulations.”With appropriate policy response,China’s economy will be poised to achieve the goal of doubling real GDP per capita by 2035,marking a large stride in its economic aggregate and urban and rural household per capita incomes.展开更多
In 70 years since the founding of the People’s Republic of China,China has successfully transitioned from a closed economy to an open economy with the watershed year of reform and opening up in 1978 and modernized it...In 70 years since the founding of the People’s Republic of China,China has successfully transitioned from a closed economy to an open economy with the watershed year of reform and opening up in 1978 and modernized its social security system accordingly.This paper divides the transition of China’s social security system into seven stages before and after 1978.The traditional social security system was predicated on the dominant public ownership,a highly centralized economy,and“full employment.”It was congruous with the ownership structure,income distribution,and labor systems under the closed economy.The modern social security system is developed to meet the needs of an open economy and promotes economic development by giving play to consumption and investment,facilitating labor flow,and boosting productivity.The modern social security system requires further supply-side structural reforms to promote the high-quality development of the open economy.展开更多
Alkali and alkaline‐earth metals from fly ash have a significant deactivation effect on catalysts used for selective catalytic reduction of NOx by NH3(NH3‐SCR).Bromides are considered effective additives to improve ...Alkali and alkaline‐earth metals from fly ash have a significant deactivation effect on catalysts used for selective catalytic reduction of NOx by NH3(NH3‐SCR).Bromides are considered effective additives to improve Hg0 oxidation on SCR catalysts.In this work,the effects of different bromides(NH4Br,NaBr,KBr,and CaBr2)on a commercial V2O5‐WO3/TiO2 catalyst were studied.NOx conversion decreased significantly over the KBr‐poisoned catalyst(denoted as L‐KBr),while that over NaBr‐and CaBr2‐poisoned catalysts(denoted as L‐NaBr and L‐CaBr,respectivity)decreased to a lesser extent compared with the fresh sample.Poor N2 selectivity was observed over L‐NaBr,L‐KBr and L‐CaBr catalysts.The decrease in the ratio of chemisorbed oxygen to total surface oxygen(Oα/(Oα+Oβ+Ow)),reducibility and surface acidity might contribute to the poor activity and N2 selectivity over L‐KBr catalyst.The increased Oαratio was conducive to the enhanced reducibility of L‐CaBr.Combined with enhanced surface acidity,this might offset the negative effect of the loss of active sites by CaBr2 covering.The overoxidation of NH3 and poor N2 selectivity in NH3 oxidation should retard the SCR activity at high temperatures over L‐CaBr catalyst.The increased basicity might contribute to increased NOx adsorption on L‐KBr and L‐CaBr catalysts.A correlation between the acid‐basic and redox properties of bromide‐poisoned catalysts and their catalytic properties is established.展开更多
Water oxidation is significant in both natural and artificial photosynthesis.In nature,water oxidation occurs at the oxygen‐evolving center of photosystem II,and leads to the generation of oxygen,protons,and electron...Water oxidation is significant in both natural and artificial photosynthesis.In nature,water oxidation occurs at the oxygen‐evolving center of photosystem II,and leads to the generation of oxygen,protons,and electrons.The last two are used for fixation of carbon dioxide to give carbohydrates.In artificial processes,the coupling of water oxidation to evolve O2and water reduction to evolve H2is known as water splitting,which is an attractive method for solar energy conversion and storage.Because water oxidation is a thermodynamically uphill reaction and is kinetically slow,this reaction causes a bottleneck in large‐scale water splitting.As a consequence,the development of new and efficient water oxidation catalysts(WOCs)has attracted extensive attention.Recent efforts have identified a variety of mononuclear earth‐abundant transition‐metal complexes as active and stable molecular WOCs.This review article summarizes recent progress in research on mononuclear catalysts that are based on first‐row transition‐metal elements,namely manganese,iron,cobalt,nickel,and copper.Particular attention is paid to catalytic mechanisms and the key O?O bond formation steps.This information is critical for designing new catalysts that are highly efficient and stable.展开更多
Set at the interface between second language acquisition and second language writing,this study examines how different types of written corrective feedback(WCF)influence the writing accuracy of Chinese college student...Set at the interface between second language acquisition and second language writing,this study examines how different types of written corrective feedback(WCF)influence the writing accuracy of Chinese college students learning English as a Foreign Language(EFL)and whether WCF facilitates the students’grasp of the focused linguistic knowledge.The participants(n=60)were divided into direct correction group(n=20),indirect error-coding group(n=20)and metalinguistic explanation group(n=20).The three groups wrote four essays in two months and received WCF for the first three essays on the five targeted error types,namely tense errors,confusion of different forms of a word,word(articles,prepositions,etc.)missing,errors in subjectverb agreement and inappropriate verb-noun collocations.The results show that all three types of WCF improved students’writing accuracy but none of them had any statistical advantage,and the metalinguistic WCF was more effective than the other two forms in facilitating the acquisition of the targeted linguistic features.These results shed some light on teaching and consolidation of language points through writing in EFL contexts.展开更多
Ice Silk Road contains abundant oil and gas sources.The total amount of oil and gas resources found alongside the Arctic region covered by Russia totalled 290 billion barrels of oil equivalent,which takes up 88.2%of t...Ice Silk Road contains abundant oil and gas sources.The total amount of oil and gas resources found alongside the Arctic region covered by Russia totalled 290 billion barrels of oil equivalent,which takes up 88.2%of the total volume discovered in the Arctic region.Eleven large oil and gas fields containing more than 5 billion barrels of oil equivalent have been discovered alongside the ice silk road,10 of which are in the West Siberian Basin;54 large oil and gas fields containing 0.5-5 billion barrels of oil equivalent have been discovered,43 of which are in Russia.展开更多
A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silve...A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silver catalyst.The Lewis acidity of the silver catalyst affected the different types of substrate diastereoselectivities;It also led to the formation of amine‐exchange side products.展开更多
Guided by the“Belt and Road”Initiative,China strengthens the in-depth cooperation in energy sectors with all regions around the world for purpose of energy security under an open context.In the past two years,China ...Guided by the“Belt and Road”Initiative,China strengthens the in-depth cooperation in energy sectors with all regions around the world for purpose of energy security under an open context.In the past two years,China made outstanding energy cooperation achievements in four aspects.展开更多
基金supported by National Water Pollution Control and Treatment Science and Technology Major Project(2018ZX07110003)Key Research and Development Project of Shandong Province(2018CXGC1007)~~
文摘A BiOCl-Bi12O17Cl2 nanocomposite with a high visible-light response and a low photoinduced electron-hole pair recombination rate was successfully synthesized using an ultrasonic-hydrothermal method.The texture,structure,optical,and photocatalytic properties of the composite were characterized.The results showed that the composite had a sheet flower-like structure with a large specific surface area.Ultraviolet-visible diffuse reflection spectra and photoluminescence spectra showed that the composite had an excellent visible-light response and a low recombination rate of photoinduced electron hole pairs.The photocatalytic property of the composite was evaluated by the removal efficiency of rhodamine B and ciprofloxacin under visible-light illumination.The composite’s reaction rate constant of removing rhodamine B(/ciprofloxacin)was approximately 8.14(/4.94),42.63(/11.91)and 64.66(/36.07)times that of Bi12O17Cl2,P25,and BiOCl,respectively.Furthermore,the composite showed a wide applicable pH range and excellent reusability.Mechanism analysis showed that photogenerated holes played a dominant role and·O2–also contributed to photocatalytic degradation.In summary,this study presents a high-efficiency photocatalyst for wastewater treatment.
文摘Reasonable income distribution and eradication of rural poverty are vital for building a moderately prosperous society in all respects in China.This paper primarily examines the income distribution and poverty reduction effects of social security spending.Market income and redistribution policies are two determinants of income gaps.Based on CHIP2018 household survey data,we find that inadequate income redistribution policies have contributed to yawning income gaps,and that social security spending is more redistributive than personal income tax and social security contributions.After estimating the redistribution effects of social security spending and itemized incomes,we find that pension payments have contributed the most to household income gaps,and that subsistence protection and rural pension payments help improve income distribution.With respect to the poverty reduction effects of social security spending,we have estimated China’s current poverty incidence and the poverty reduction effects of pension payments,healthcare,and educational allowances with CHIP2018 data,and discover that an increase in social security spending may effectively reduce rural poverty.In building a moderately prosperous society in all respects,China should increase social security spending,focusing on specific target groups,and promote the role of social security spending in regulating income distribution and offering social protection to rural residents.
文摘The time period between 2020 and 2035 is vital for China to achieve its second centennial goal.During this period,China must avoid the middle-income trap and achieve socialist modernization.To accomplish this goal,China must maintain a certain pace of economic growth and strive to double its real GDP per capita by 2035.However,by the current growth trajectory,China’s average economic growth rate is expected to stay at approximately 3.8%over the period between 2020-2035.This makes the GDP per capita growth target hard to achieve.Even when in a high-quality development stage,China should speed up economic growth while enhancing growth quality.Speed and quality are interdependent rather than contradictory with each other.To ramp up economic growth potentials,China must proceed with market-oriented reforms and shift economic growth drivers.To improve economic growth quality,household consumption should be increased to unleash China’s full potential,not only as the factory floor of the world but also one of world’s biggest markets,i.e.“dual circulations.”With appropriate policy response,China’s economy will be poised to achieve the goal of doubling real GDP per capita by 2035,marking a large stride in its economic aggregate and urban and rural household per capita incomes.
文摘In 70 years since the founding of the People’s Republic of China,China has successfully transitioned from a closed economy to an open economy with the watershed year of reform and opening up in 1978 and modernized its social security system accordingly.This paper divides the transition of China’s social security system into seven stages before and after 1978.The traditional social security system was predicated on the dominant public ownership,a highly centralized economy,and“full employment.”It was congruous with the ownership structure,income distribution,and labor systems under the closed economy.The modern social security system is developed to meet the needs of an open economy and promotes economic development by giving play to consumption and investment,facilitating labor flow,and boosting productivity.The modern social security system requires further supply-side structural reforms to promote the high-quality development of the open economy.
基金supported by the National Key R&D Program of China(2016YFC0203900,2016YFC0203901)National Natural Science Foundation of China(51778619,21577173)~~
文摘Alkali and alkaline‐earth metals from fly ash have a significant deactivation effect on catalysts used for selective catalytic reduction of NOx by NH3(NH3‐SCR).Bromides are considered effective additives to improve Hg0 oxidation on SCR catalysts.In this work,the effects of different bromides(NH4Br,NaBr,KBr,and CaBr2)on a commercial V2O5‐WO3/TiO2 catalyst were studied.NOx conversion decreased significantly over the KBr‐poisoned catalyst(denoted as L‐KBr),while that over NaBr‐and CaBr2‐poisoned catalysts(denoted as L‐NaBr and L‐CaBr,respectivity)decreased to a lesser extent compared with the fresh sample.Poor N2 selectivity was observed over L‐NaBr,L‐KBr and L‐CaBr catalysts.The decrease in the ratio of chemisorbed oxygen to total surface oxygen(Oα/(Oα+Oβ+Ow)),reducibility and surface acidity might contribute to the poor activity and N2 selectivity over L‐KBr catalyst.The increased Oαratio was conducive to the enhanced reducibility of L‐CaBr.Combined with enhanced surface acidity,this might offset the negative effect of the loss of active sites by CaBr2 covering.The overoxidation of NH3 and poor N2 selectivity in NH3 oxidation should retard the SCR activity at high temperatures over L‐CaBr catalyst.The increased basicity might contribute to increased NOx adsorption on L‐KBr and L‐CaBr catalysts.A correlation between the acid‐basic and redox properties of bromide‐poisoned catalysts and their catalytic properties is established.
基金supported by Thousand Talents Program of Chinathe National Natural Science Foundation of China (21101170,21573139,and 21773146)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Shaanxi Normal University
文摘Water oxidation is significant in both natural and artificial photosynthesis.In nature,water oxidation occurs at the oxygen‐evolving center of photosystem II,and leads to the generation of oxygen,protons,and electrons.The last two are used for fixation of carbon dioxide to give carbohydrates.In artificial processes,the coupling of water oxidation to evolve O2and water reduction to evolve H2is known as water splitting,which is an attractive method for solar energy conversion and storage.Because water oxidation is a thermodynamically uphill reaction and is kinetically slow,this reaction causes a bottleneck in large‐scale water splitting.As a consequence,the development of new and efficient water oxidation catalysts(WOCs)has attracted extensive attention.Recent efforts have identified a variety of mononuclear earth‐abundant transition‐metal complexes as active and stable molecular WOCs.This review article summarizes recent progress in research on mononuclear catalysts that are based on first‐row transition‐metal elements,namely manganese,iron,cobalt,nickel,and copper.Particular attention is paid to catalytic mechanisms and the key O?O bond formation steps.This information is critical for designing new catalysts that are highly efficient and stable.
文摘Set at the interface between second language acquisition and second language writing,this study examines how different types of written corrective feedback(WCF)influence the writing accuracy of Chinese college students learning English as a Foreign Language(EFL)and whether WCF facilitates the students’grasp of the focused linguistic knowledge.The participants(n=60)were divided into direct correction group(n=20),indirect error-coding group(n=20)and metalinguistic explanation group(n=20).The three groups wrote four essays in two months and received WCF for the first three essays on the five targeted error types,namely tense errors,confusion of different forms of a word,word(articles,prepositions,etc.)missing,errors in subjectverb agreement and inappropriate verb-noun collocations.The results show that all three types of WCF improved students’writing accuracy but none of them had any statistical advantage,and the metalinguistic WCF was more effective than the other two forms in facilitating the acquisition of the targeted linguistic features.These results shed some light on teaching and consolidation of language points through writing in EFL contexts.
文摘Ice Silk Road contains abundant oil and gas sources.The total amount of oil and gas resources found alongside the Arctic region covered by Russia totalled 290 billion barrels of oil equivalent,which takes up 88.2%of the total volume discovered in the Arctic region.Eleven large oil and gas fields containing more than 5 billion barrels of oil equivalent have been discovered alongside the ice silk road,10 of which are in the West Siberian Basin;54 large oil and gas fields containing 0.5-5 billion barrels of oil equivalent have been discovered,43 of which are in Russia.
基金the National Natural Science Foundation of China(21472237)~~
文摘A new method was developed to diastereoselectively synthesize polysubstituted 1,2‐diamine compounds from the reaction of diazoesters with arylamines and diaryl imines by using the dioxazoline ligand L2‐ligated silver catalyst.The Lewis acidity of the silver catalyst affected the different types of substrate diastereoselectivities;It also led to the formation of amine‐exchange side products.
文摘Guided by the“Belt and Road”Initiative,China strengthens the in-depth cooperation in energy sectors with all regions around the world for purpose of energy security under an open context.In the past two years,China made outstanding energy cooperation achievements in four aspects.