A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of ...A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of main components of crude lead,separation coefficients and vapor-liquid equilibrium composition of Pb-i（i stands for an impurity） system at different temperatures.The behaviors of impurities in the vacuum distillation refining process were investigated.The results show that the vacuum distillation should be taken to obtain lead from crude lead,in which Zn,As and partial Sb are volatilized at lower temperature of 923-1023 K.Lead is distilled from the residue containing Cu,Sn,Ag and Bi at higher temperature of 1323-1423 K,but the impurity Bi is also volatilized along with lead and cannot be separated from lead.展开更多
Based on the molecular interaction volume model （MIVM）, the activities of components of Pb Sn Sb ternary alloy were predicted. The vapo^liquid phase equilibrium of Pb-Sn-Sb alloy system was calculated using the acti...Based on the molecular interaction volume model （MIVM）, the activities of components of Pb Sn Sb ternary alloy were predicted. The vapo^liquid phase equilibrium of Pb-Sn-Sb alloy system was calculated using the activity coefficients of Pb Sn-Sb alloy system in the process of vacuum distillation. The calculated results show that the content of Sn in vapor phase increases with the increasing distillation temperature and content of Sn in liquid phase. However, the content of Sn in vapor phase is only 0.45% （mass fraction） while 97% in liquid phase at 1100 ℃, which shows that the separating effect is very well. Experimental investigations on the separation of Pb-Sn-Sb ternary alloy were carried out in the distillation temperature range of 1100-1300 ℃ under vacuum condition. It is found that the Sn content in vapor phase is 0.54% while 97% in liquid phase at 1100 ℃. Finally, the predicted data were compared with the experimental results showing good agreement with each other.展开更多
[Objective] The paper was to study the spatial variation characteristics of soil available plumbum （Pb） in vegetable bases of Urumqi City. [Method] With the vegetable base in northern suburb of Urumqi city as a typi...[Objective] The paper was to study the spatial variation characteristics of soil available plumbum （Pb） in vegetable bases of Urumqi City. [Method] With the vegetable base in northern suburb of Urumqi city as a typical area, the structure feature of soil available Pb content in suburb of oasis city in the arid area was ana- lyzed to get the spatial distribution pattern of available Pb, the origin and pollution source of this distribution pattern were also revealed. [Result] The available Pb in vegetable base of northern suburb in Urumqi City belonged to moderate variation. Semivariance model fitting showed that available Pb content could be fit with expo- nential function, which had spatial correlation within a certain range. The spatial dis- tribution pattern of available Pb content was obtained by using optimal Kriging inter- polation, and indicated that soil available Pb content was closely related to industrial activities, sewage irrigation and atmospheric dust. [Conclusion] The study provided the scientific basis for recognition, pollution risk assessment and pollution control of Pb pollution sources in the region, which have great significance on creating safe and clean production environment and selecting reasonable vegetable planting districts.展开更多
[Objective] This study was conducted to investigate soil heavy metal Pb pol ution level and spatial distribution characteristics at two sides of arterial traffic in Yel ow River delta area. [Method] Soil samples were ...[Objective] This study was conducted to investigate soil heavy metal Pb pol ution level and spatial distribution characteristics at two sides of arterial traffic in Yel ow River delta area. [Method] Soil samples were col ected by sample-plot sur-vey method, and soil Pb pol ution condition in road area of Yel ow River delta was determined and analyzed by atomic absorption spectrometry. [Result] Pb pol ution at two sides of national road G205 and provincial road S312 was mainly from auto-mobile exhaust, and Pb content in soil decreased with the distance from road in-creasing. Soil samples col ected at points with distances in the range of 1-50 m from truck road of G205 was 32.46-86.04 mg/kg, which was 1.2-3.3 times of soil Pb background value in this area, and the pol ution was more remarkable. Further study showed that green belt aside road could effectively reduce soil Pb pol ution level. [Conclusion] This study provides theoretical basis and basic information for in-vestigation of soil heavy metal Pb pol ution level and spatial distribution characteris-tics at two sides of arterial traffic in Yel ow River delta area.展开更多
[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead polluti...[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead pollution. [Method] A. philoxeroides in water culture was treated with different concentration of lead,and then,its external injury was observed,its growth and physiological indexes were measured. [Result] A. philoxeroides biomass and chlorophyll content decreased; conductivity and malonaldehyde （MDA ） content were increased; the SOD,POD and CAT activities showed a trend of first increase and then decrease with increase in concentration of lead stress. [Conclusion] With increase in lead concentration,the cell membrane permeability increased and MDA had a higher accumulation,antioxidant enzymes activity decreased,the normal oxidative metabolism of A. philoxeroides was severely affected,leading it to wilt.展开更多
Nonlinear dynamic inversion(NDI)has been applied to the control law design of quad-rotors mainly thanks to its good robustness and simplicity of parameter tuning.However,the weakness of relying on accurate model great...Nonlinear dynamic inversion(NDI)has been applied to the control law design of quad-rotors mainly thanks to its good robustness and simplicity of parameter tuning.However,the weakness of relying on accurate model greatly restrains its application on quad-rotors,especially nano quad-rotors(NQRs).NQRs are easy to be influenced by uncertainties such as model uncertainties(mainly from complicated aerodynamic interferences,strong coupling in roll-pitch-yaw channels and inaccurate aerodynamic prediction of rotors)and external uncertainties(mainly from winds or gusts),particularly persistent ones.Therefore,developing accurate model for altitude and attitude control of NQRs is difficult.To solve this problem,in this paper,an improved nonlinear dynamic inversion(INDI)method is developed,which can reject the above-mentioned uncertainties by estimating them and then counteracting in real time using linear extended state observer(LESO).Comparison with the traditional NDI(TNDI)method was carried out numerically,and the results show that,in coping with persistent uncertainties,the INDI-based method presents significant superiority.展开更多
The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically. The volatilization rates and mass fractions of elements, influenced by distillation temperature, hea...The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically. The volatilization rates and mass fractions of elements, influenced by distillation temperature, heat preservation time and material thickness, were investigated under laboratory conditions. The experimental results indicate that almost all of lead and bismuth can be separated from silver-contained multicomponent alloy at 1 223 K for 45 min when the chamber pressure maintains at 10-25 Pa. Silver can be easily enriched in the residue and its mass fraction increases from 3.6% to 27.8% when the distillation temperature is between 1 133 K and 1 373 K. Due to the forming ofintermetallic compounds Cu2Sb, Cul0Sb3 and Ag3Sb, the antimony could not be evaporated completely during the vacuum distillation. EDS analysis indicates that the condensate has a columnar crystal structure.展开更多
Electric bicycles powered by lead-acid batteries have developed very fast for several years in China. Because the inconvenience caused by the service performance and the inconsistency to the environmental protection p...Electric bicycles powered by lead-acid batteries have developed very fast for several years in China. Because the inconvenience caused by the service performance and the inconsistency to the environmental protection policy of the lead-acid battery, the zinc-air power battery was proposed to solve the problem in this paper. The advantage and the feasibility of developing zinc-air power batteries in China have been illustrated in the paper. And, it is represented that development of electric bicycles powered by the zinc-air power battery also can accelerate this kind of battery's development in other electric vehicles, which is favorable to economic development and environmental protection.展开更多
The main aim of this work is to study numerically the influence of an external magnetic field on the solidification processes of two-component materials. Based on the continuum model of two-phase flow a mathematical m...The main aim of this work is to study numerically the influence of an external magnetic field on the solidification processes of two-component materials. Based on the continuum model of two-phase flow a mathematical model for the directional solidification of a binary alloy in a magnetic field is presented. The model includes mass, momentum, energy and species mass conservation equations written in compressible form and additional relationships describing the temperature-solute coupling. The geometry under study is a cylindrical mold with adiabatic walls and cooled bottom. The macroscale transport in the solidification of alloys is governed by the progress of the two-phase mushy zone, which is treated by means of a porous medium approach. The volume fraction of liquid and solid phases, respectively, is calculated from a 2D approximation of the phase diagram. The results of calculation are compared with experimental data.展开更多
Perovskite solar cells(PSCs)attract widespread research interest due to their exceptional properties.However,the instability of the perovskite layer,especially the moisture instability,and existing defects seriously r...Perovskite solar cells(PSCs)attract widespread research interest due to their exceptional properties.However,the instability of the perovskite layer,especially the moisture instability,and existing defects seriously restrict the performance and limit the development of PSCs towards commercialization.Herein,we fabricate moisture-stable and efficient PSCs by incorporating a thiamine(THM)additive into a lead iodide(PbI_(2))precursor using a two-step spin-coating method.This strategy enables a better interaction between the THM additive and PbI_(2).Then,a higher energy barrier is produced when the material reacts with A-site cations to form perovskite crystals,resulting in larger grains and better-quality perovskite films.Through optimization of the concentration of the THM additive,the optimal perovskite achieves improved moisture stability and decreased trap states;thus,the corresponding unencapsulated devices achieve a remarkable power conversion efficiency(PCE)of 21.40%and maintain>92%of their initial PCE after 180 h in ambient air(~50%humidity).The excellent performance is mainly attributed to the fact that THM promotes crystal growth and passivates defects in perovskite films.展开更多
基金Project (2012CB722803) supported by the National Basic Research Program of ChinaProject (U1202271) supported by the National Natural Science Foundation of China
文摘A novel technique was developed to remove impurities from crude lead by vacuum distillation.The thermodynamics on vacuum distillation refining process of crude lead was studied by means of saturated vapor pressure of main components of crude lead,separation coefficients and vapor-liquid equilibrium composition of Pb-i（i stands for an impurity） system at different temperatures.The behaviors of impurities in the vacuum distillation refining process were investigated.The results show that the vacuum distillation should be taken to obtain lead from crude lead,in which Zn,As and partial Sb are volatilized at lower temperature of 923-1023 K.Lead is distilled from the residue containing Cu,Sn,Ag and Bi at higher temperature of 1323-1423 K,but the impurity Bi is also volatilized along with lead and cannot be separated from lead.
基金Project(2012CB722803) supported by the National Basic Research Program of ChinaProject(2011FA008) supported by the Key Projectof Science and Technology Program of Yunnan Province,China
文摘Based on the molecular interaction volume model （MIVM）, the activities of components of Pb Sn Sb ternary alloy were predicted. The vapo^liquid phase equilibrium of Pb-Sn-Sb alloy system was calculated using the activity coefficients of Pb Sn-Sb alloy system in the process of vacuum distillation. The calculated results show that the content of Sn in vapor phase increases with the increasing distillation temperature and content of Sn in liquid phase. However, the content of Sn in vapor phase is only 0.45% （mass fraction） while 97% in liquid phase at 1100 ℃, which shows that the separating effect is very well. Experimental investigations on the separation of Pb-Sn-Sb ternary alloy were carried out in the distillation temperature range of 1100-1300 ℃ under vacuum condition. It is found that the Sn content in vapor phase is 0.54% while 97% in liquid phase at 1100 ℃. Finally, the predicted data were compared with the experimental results showing good agreement with each other.
基金Supported by Scientific Research Project for Universitie in Xinjiang Uygur Autonomous Region(XJEDU2005I08)China-Italian Cooperation Projects for Environmental Protection~~
文摘[Objective] The paper was to study the spatial variation characteristics of soil available plumbum （Pb） in vegetable bases of Urumqi City. [Method] With the vegetable base in northern suburb of Urumqi city as a typical area, the structure feature of soil available Pb content in suburb of oasis city in the arid area was ana- lyzed to get the spatial distribution pattern of available Pb, the origin and pollution source of this distribution pattern were also revealed. [Result] The available Pb in vegetable base of northern suburb in Urumqi City belonged to moderate variation. Semivariance model fitting showed that available Pb content could be fit with expo- nential function, which had spatial correlation within a certain range. The spatial dis- tribution pattern of available Pb content was obtained by using optimal Kriging inter- polation, and indicated that soil available Pb content was closely related to industrial activities, sewage irrigation and atmospheric dust. [Conclusion] The study provided the scientific basis for recognition, pollution risk assessment and pollution control of Pb pollution sources in the region, which have great significance on creating safe and clean production environment and selecting reasonable vegetable planting districts.
基金Supported by Scientific Research Development Planning Project of Education Department of Shandong Province(J08LD51)~~
文摘[Objective] This study was conducted to investigate soil heavy metal Pb pol ution level and spatial distribution characteristics at two sides of arterial traffic in Yel ow River delta area. [Method] Soil samples were col ected by sample-plot sur-vey method, and soil Pb pol ution condition in road area of Yel ow River delta was determined and analyzed by atomic absorption spectrometry. [Result] Pb pol ution at two sides of national road G205 and provincial road S312 was mainly from auto-mobile exhaust, and Pb content in soil decreased with the distance from road in-creasing. Soil samples col ected at points with distances in the range of 1-50 m from truck road of G205 was 32.46-86.04 mg/kg, which was 1.2-3.3 times of soil Pb background value in this area, and the pol ution was more remarkable. Further study showed that green belt aside road could effectively reduce soil Pb pol ution level. [Conclusion] This study provides theoretical basis and basic information for in-vestigation of soil heavy metal Pb pol ution level and spatial distribution characteris-tics at two sides of arterial traffic in Yel ow River delta area.
基金Supported by National Natural Science Foundation of China(31060031)Youth Foundation of Yunnan University of Nationalities(09QN02)~~
文摘[Objective] The paper aimed to discuss effects of different concentrations of lead stress on Alternanthera philoxeroides growth and physiological indices,to explore phytoremediation methods for removal of lead pollution. [Method] A. philoxeroides in water culture was treated with different concentration of lead,and then,its external injury was observed,its growth and physiological indexes were measured. [Result] A. philoxeroides biomass and chlorophyll content decreased; conductivity and malonaldehyde （MDA ） content were increased; the SOD,POD and CAT activities showed a trend of first increase and then decrease with increase in concentration of lead stress. [Conclusion] With increase in lead concentration,the cell membrane permeability increased and MDA had a higher accumulation,antioxidant enzymes activity decreased,the normal oxidative metabolism of A. philoxeroides was severely affected,leading it to wilt.
基金supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the Advanced Research Project of Army Equipment Development(No.301020803)
文摘Nonlinear dynamic inversion(NDI)has been applied to the control law design of quad-rotors mainly thanks to its good robustness and simplicity of parameter tuning.However,the weakness of relying on accurate model greatly restrains its application on quad-rotors,especially nano quad-rotors(NQRs).NQRs are easy to be influenced by uncertainties such as model uncertainties(mainly from complicated aerodynamic interferences,strong coupling in roll-pitch-yaw channels and inaccurate aerodynamic prediction of rotors)and external uncertainties(mainly from winds or gusts),particularly persistent ones.Therefore,developing accurate model for altitude and attitude control of NQRs is difficult.To solve this problem,in this paper,an improved nonlinear dynamic inversion(INDI)method is developed,which can reject the above-mentioned uncertainties by estimating them and then counteracting in real time using linear extended state observer(LESO).Comparison with the traditional NDI(TNDI)method was carried out numerically,and the results show that,in coping with persistent uncertainties,the INDI-based method presents significant superiority.
基金Project(2010CI009) supported by Science Foundation of Yunnan Province,ChinaProjects(U1202271) supported by the National Natural Science Foundation of China
文摘The feasibility of separation of lead anode slime with low silver by vacuum distillation was analyzed theoretically. The volatilization rates and mass fractions of elements, influenced by distillation temperature, heat preservation time and material thickness, were investigated under laboratory conditions. The experimental results indicate that almost all of lead and bismuth can be separated from silver-contained multicomponent alloy at 1 223 K for 45 min when the chamber pressure maintains at 10-25 Pa. Silver can be easily enriched in the residue and its mass fraction increases from 3.6% to 27.8% when the distillation temperature is between 1 133 K and 1 373 K. Due to the forming ofintermetallic compounds Cu2Sb, Cul0Sb3 and Ag3Sb, the antimony could not be evaporated completely during the vacuum distillation. EDS analysis indicates that the condensate has a columnar crystal structure.
基金Anhui Exploitation Fund of Person with Ability( 2006Z029).
文摘Electric bicycles powered by lead-acid batteries have developed very fast for several years in China. Because the inconvenience caused by the service performance and the inconsistency to the environmental protection policy of the lead-acid battery, the zinc-air power battery was proposed to solve the problem in this paper. The advantage and the feasibility of developing zinc-air power batteries in China have been illustrated in the paper. And, it is represented that development of electric bicycles powered by the zinc-air power battery also can accelerate this kind of battery's development in other electric vehicles, which is favorable to economic development and environmental protection.
文摘The main aim of this work is to study numerically the influence of an external magnetic field on the solidification processes of two-component materials. Based on the continuum model of two-phase flow a mathematical model for the directional solidification of a binary alloy in a magnetic field is presented. The model includes mass, momentum, energy and species mass conservation equations written in compressible form and additional relationships describing the temperature-solute coupling. The geometry under study is a cylindrical mold with adiabatic walls and cooled bottom. The macroscale transport in the solidification of alloys is governed by the progress of the two-phase mushy zone, which is treated by means of a porous medium approach. The volume fraction of liquid and solid phases, respectively, is calculated from a 2D approximation of the phase diagram. The results of calculation are compared with experimental data.
基金financially supported by the National Natural Science Foundation of China(52025028,52072254,and 52002258)the Natural Science Foundation of Jiangsu Province(BK20200877)+1 种基金the"Shuangchuang"Program of Jiangsu Provincethe Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions。
文摘Perovskite solar cells(PSCs)attract widespread research interest due to their exceptional properties.However,the instability of the perovskite layer,especially the moisture instability,and existing defects seriously restrict the performance and limit the development of PSCs towards commercialization.Herein,we fabricate moisture-stable and efficient PSCs by incorporating a thiamine(THM)additive into a lead iodide(PbI_(2))precursor using a two-step spin-coating method.This strategy enables a better interaction between the THM additive and PbI_(2).Then,a higher energy barrier is produced when the material reacts with A-site cations to form perovskite crystals,resulting in larger grains and better-quality perovskite films.Through optimization of the concentration of the THM additive,the optimal perovskite achieves improved moisture stability and decreased trap states;thus,the corresponding unencapsulated devices achieve a remarkable power conversion efficiency(PCE)of 21.40%and maintain>92%of their initial PCE after 180 h in ambient air(~50%humidity).The excellent performance is mainly attributed to the fact that THM promotes crystal growth and passivates defects in perovskite films.
