Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should b...Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.展开更多
The microstructure evolution and its effects on the mechanical performance of 2000 MPa bridge cable steel wires were investigated by transmission electron microscope(TEM),electron backscatter diffraction(EBSD),X-ray d...The microstructure evolution and its effects on the mechanical performance of 2000 MPa bridge cable steel wires were investigated by transmission electron microscope(TEM),electron backscatter diffraction(EBSD),X-ray diffractometer(XRD)and mechanical tests.Experimental results reveal that,with the increasing strain from 0 to 1.42,a fiber structure and a<110>fiber texture aligned with the wire axis are gradually developed accompanied by cementite decomposition and the formation of sub-grains;the tensile strength increases linearly from 1510 to 2025 MPa,and the reduction of the area is stable with a slight decline from 44%to 36%.After annealing at 450℃for different times,pronounced changes in the microstructure occur.Cementite lamella fragment into coarser globules corresponding to a remarkable spheroidization process,while ferrite domains recover and recrystallize,and this process is associated to modifications in the mechanical properties.Furthermore,based on the observations on dislocation lines crossing through cementite lamellae,a possible mechanism of cementite decomposition is discussed.展开更多
The characteristic of near-surface microstructure and its effects on the torsion performance of cold-drawn pearlitic steel wires for bridge cables were investigated by focused ion beam-scanning electron microscope,tra...The characteristic of near-surface microstructure and its effects on the torsion performance of cold-drawn pearlitic steel wires for bridge cables were investigated by focused ion beam-scanning electron microscope,transmission electron microscopy and differential scanning calorimetry.The samples with similar tensile strength before and after hot-dip galvanizing process are,respectively,characterized as delaminated and non-delaminated in torsion test which indicates that the tensile strength is independent of the toughness value(i e,reduction area and torsion ability).It is interesting to find that there exists submicron granular ferrite on near-surface of the wires,which can be attributed to dislocation rearrangement and sub-grains rotation during cold drawing and hot-dip galvanizing process.And their distribution can suggest homogeneousness of deformation degree to a certain extent:the closer to the surface of their distribution,the more homogeneous deformation of the wires.There is a close relationship between the thermal stability of the cementite layer and distribution of granular ferrite:differential scanning calorimetry(DSC)analysis shows that the sample is accompanied by submicron granular ferrite which is located closer to the surface has higher thermal stability under galvanizing temperature(450°C).A new mechanism of the torsion delamination of pearlitic steel wires is discussed in terms of the thermal stability of the cementite layer and distribution of granular ferrite.展开更多
One new triterpcnoid saponin, quinquenoside L17 （1）, was isolated from the leaves and stems of Panax quinquefolium L., and its structure was elucidated as 20-O-[（β-D-xylopyranosyl-（1-6）-O-β-D-glucopyranosy）]-6...One new triterpcnoid saponin, quinquenoside L17 （1）, was isolated from the leaves and stems of Panax quinquefolium L., and its structure was elucidated as 20-O-[（β-D-xylopyranosyl-（1-6）-O-β-D-glucopyranosy）]-6-O-β-D-glucopyranosy1-dammar-24-ene- 3,6,12,20-tetraol, by the combination analysis of one-dimensional NMR and two-dimensional NMR, mass spectrometry, CD spectrum and chemical evidences.展开更多
A new compound, kudinoside LZ2 （1）, was isolated from the leaves of llex kudincha. Its structure was elucidated by the combination of one- and two-dimensional NMR analysis, HR-ESI-MS, CD spectrum measurement and che...A new compound, kudinoside LZ2 （1）, was isolated from the leaves of llex kudincha. Its structure was elucidated by the combination of one- and two-dimensional NMR analysis, HR-ESI-MS, CD spectrum measurement and chemical evidences.展开更多
Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is stil...Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is still a challenge to figure out the contributions and originating regions for different sources of atmospheric NACs.Here,field observations on fine particulate NACs were conducted at a coastal rural area in Qingdao,China in the winter of 2018 and 2019.The mean total concentrations of fine particulate nitro-aromatic compounds were 125.0±89.5 and 27.7±21.1 ng/m^(3)in the winter of 2018 and 2019,respectively.Among the measured eleven NACs,nitrophenols and nitrocatechols were the most abundant species.Variation characteristics and correlation analysis showed that humidity and anthropogenic primary emissions had significant influences on the NAC abundances.In this study,two tracing methods of the improved spatial concentration weighted trajectory(SCWT)model and the receptor model of positive matrix factorization(PMF)were combined to comprehensively understand the origins of NACs in fine particles at coastal Qingdao.Four major sources were identified,including coal combustion,biomass burning,vehicle exhaust,and secondary formation.Surprisingly,coal combustion was responsible for about half of the observed nitro-aromatic compounds,followed by biomass burning(~30%).The results by SCWT demonstrated that the coal combustion dominated NACs mainly originated from the Shandong peninsula and the areas to the north and southwest,while those dominated by biomass burning primarily came from local Qingdao and the areas to the west.展开更多
快速城市化背景下,城市绿色空间为人与自然的接触提供了宝贵机会。生物多样性作为绿色空间的基本要素,是连接人与自然的重要纽带。关于绿色空间生物多样性感知的既有研究多关注于单一对象或主题,尚缺少系统性梳理,厘清该领域研究脉络,...快速城市化背景下,城市绿色空间为人与自然的接触提供了宝贵机会。生物多样性作为绿色空间的基本要素,是连接人与自然的重要纽带。关于绿色空间生物多样性感知的既有研究多关注于单一对象或主题,尚缺少系统性梳理,厘清该领域研究脉络,将为从生物多样性感知方面开展城市绿色空间设计提供参考。文章以中国知网及Web of Science数据库为基础,对相关文献进行检索和统计分析,结果发现:1)当前研究热点为生物多样性感知偏好与影响因素,基于生物多样性感知的健康恢复效益与生态系统文化服务,以及各尺度生物多样性感知差异等;2)常用研究方法为现场实验、控制实验、模型模拟和网络数据分析4大类。基于研究结果,提出未来研究趋势包括:1)生物多样性感知研究新方向探索,如不同气候的影响、与生物多样性保护协调、感知行为研究等;2)通过综合现有方法、引入新兴技术、结合多感官等,探索感知研究的新方法。3)探索生物多样性感知与城市绿色空间设计结合的新方式。展开更多
China’s urbanization level has reached a new stage.Urban development has changed from incremental expansion to inventory renewal.The demand of residents for a good living environment and compact living space is incre...China’s urbanization level has reached a new stage.Urban development has changed from incremental expansion to inventory renewal.The demand of residents for a good living environment and compact living space is increasing.How to realize the intensive development of land based on human needs has become an urgent problem to be solved in urban development.Based on the planning concepts of inventory planning and life circle,this study made the renewal and transformation of old urban area of Medical Saint Temple in Nanyang City and analyzed the current spatial characteristic elements.Optimize the layout of public space in combination with residents’living needs,improve the functions and quality of urban areas,and build a healthy and sustainable development model to improve the living environment of the community and provide reference for the future urban renewal and transformation.展开更多
基金supported by the National Natural Science Foundation of China (Nos.42022050 and 42277088)the Guangdong Basic and Applied Basic Research Fund Committee (Nos.2021A1515011248 and 2023A1515012010)the Guangdong Foundation for the Program of Science and Technology Research (No.2020B1212060053).
文摘Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.
基金Funded by the National Key R&D Program of China(No.2017YFB0304801)
文摘The microstructure evolution and its effects on the mechanical performance of 2000 MPa bridge cable steel wires were investigated by transmission electron microscope(TEM),electron backscatter diffraction(EBSD),X-ray diffractometer(XRD)and mechanical tests.Experimental results reveal that,with the increasing strain from 0 to 1.42,a fiber structure and a<110>fiber texture aligned with the wire axis are gradually developed accompanied by cementite decomposition and the formation of sub-grains;the tensile strength increases linearly from 1510 to 2025 MPa,and the reduction of the area is stable with a slight decline from 44%to 36%.After annealing at 450℃for different times,pronounced changes in the microstructure occur.Cementite lamella fragment into coarser globules corresponding to a remarkable spheroidization process,while ferrite domains recover and recrystallize,and this process is associated to modifications in the mechanical properties.Furthermore,based on the observations on dislocation lines crossing through cementite lamellae,a possible mechanism of cementite decomposition is discussed.
基金Funded by the National Key R&D Program of China(No.2017YFB0304801)。
文摘The characteristic of near-surface microstructure and its effects on the torsion performance of cold-drawn pearlitic steel wires for bridge cables were investigated by focused ion beam-scanning electron microscope,transmission electron microscopy and differential scanning calorimetry.The samples with similar tensile strength before and after hot-dip galvanizing process are,respectively,characterized as delaminated and non-delaminated in torsion test which indicates that the tensile strength is independent of the toughness value(i e,reduction area and torsion ability).It is interesting to find that there exists submicron granular ferrite on near-surface of the wires,which can be attributed to dislocation rearrangement and sub-grains rotation during cold drawing and hot-dip galvanizing process.And their distribution can suggest homogeneousness of deformation degree to a certain extent:the closer to the surface of their distribution,the more homogeneous deformation of the wires.There is a close relationship between the thermal stability of the cementite layer and distribution of granular ferrite:differential scanning calorimetry(DSC)analysis shows that the sample is accompanied by submicron granular ferrite which is located closer to the surface has higher thermal stability under galvanizing temperature(450°C).A new mechanism of the torsion delamination of pearlitic steel wires is discussed in terms of the thermal stability of the cementite layer and distribution of granular ferrite.
基金supported by 973 Program(No.2006CB708517)Program for New Century Excellent Talents in University of Peoples Republic of China(No.NCET-04-0289)
文摘One new triterpcnoid saponin, quinquenoside L17 （1）, was isolated from the leaves and stems of Panax quinquefolium L., and its structure was elucidated as 20-O-[（β-D-xylopyranosyl-（1-6）-O-β-D-glucopyranosy）]-6-O-β-D-glucopyranosy1-dammar-24-ene- 3,6,12,20-tetraol, by the combination analysis of one-dimensional NMR and two-dimensional NMR, mass spectrometry, CD spectrum and chemical evidences.
基金supported by Program for New Century Excellent Talents in University of People's Republic of China(No.NCET-04-0289)
文摘A new compound, kudinoside LZ2 （1）, was isolated from the leaves of llex kudincha. Its structure was elucidated by the combination of one- and two-dimensional NMR analysis, HR-ESI-MS, CD spectrum measurement and chemical evidences.
基金supported by the Natural Science Foundation of Shandong Province (No.ZR2020YQ30)the National Natural Science Foundation of China (Nos.42005089,41775118)+1 种基金the Youth Innovation Program of Universities in Shandong Province (No.2019KJD007)received financial support from Shandong University (No.2020QNQT012)。
文摘Nitro-aromatic compounds(NACs)are among the major components of brown carbon(BrC)in the atmosphere,causing negative impacts on regional climate,air quality,and ecological health.Due to the extensive origins,it is still a challenge to figure out the contributions and originating regions for different sources of atmospheric NACs.Here,field observations on fine particulate NACs were conducted at a coastal rural area in Qingdao,China in the winter of 2018 and 2019.The mean total concentrations of fine particulate nitro-aromatic compounds were 125.0±89.5 and 27.7±21.1 ng/m^(3)in the winter of 2018 and 2019,respectively.Among the measured eleven NACs,nitrophenols and nitrocatechols were the most abundant species.Variation characteristics and correlation analysis showed that humidity and anthropogenic primary emissions had significant influences on the NAC abundances.In this study,two tracing methods of the improved spatial concentration weighted trajectory(SCWT)model and the receptor model of positive matrix factorization(PMF)were combined to comprehensively understand the origins of NACs in fine particles at coastal Qingdao.Four major sources were identified,including coal combustion,biomass burning,vehicle exhaust,and secondary formation.Surprisingly,coal combustion was responsible for about half of the observed nitro-aromatic compounds,followed by biomass burning(~30%).The results by SCWT demonstrated that the coal combustion dominated NACs mainly originated from the Shandong peninsula and the areas to the north and southwest,while those dominated by biomass burning primarily came from local Qingdao and the areas to the west.
文摘快速城市化背景下,城市绿色空间为人与自然的接触提供了宝贵机会。生物多样性作为绿色空间的基本要素,是连接人与自然的重要纽带。关于绿色空间生物多样性感知的既有研究多关注于单一对象或主题,尚缺少系统性梳理,厘清该领域研究脉络,将为从生物多样性感知方面开展城市绿色空间设计提供参考。文章以中国知网及Web of Science数据库为基础,对相关文献进行检索和统计分析,结果发现:1)当前研究热点为生物多样性感知偏好与影响因素,基于生物多样性感知的健康恢复效益与生态系统文化服务,以及各尺度生物多样性感知差异等;2)常用研究方法为现场实验、控制实验、模型模拟和网络数据分析4大类。基于研究结果,提出未来研究趋势包括:1)生物多样性感知研究新方向探索,如不同气候的影响、与生物多样性保护协调、感知行为研究等;2)通过综合现有方法、引入新兴技术、结合多感官等,探索感知研究的新方法。3)探索生物多样性感知与城市绿色空间设计结合的新方式。
基金Sponsored by Social Science Fund Project of Hebei Province(HB19S039)Training Project of School of Architecture and Art,Hebei University of Engineering(2020-KJZD-001).
文摘China’s urbanization level has reached a new stage.Urban development has changed from incremental expansion to inventory renewal.The demand of residents for a good living environment and compact living space is increasing.How to realize the intensive development of land based on human needs has become an urgent problem to be solved in urban development.Based on the planning concepts of inventory planning and life circle,this study made the renewal and transformation of old urban area of Medical Saint Temple in Nanyang City and analyzed the current spatial characteristic elements.Optimize the layout of public space in combination with residents’living needs,improve the functions and quality of urban areas,and build a healthy and sustainable development model to improve the living environment of the community and provide reference for the future urban renewal and transformation.
