Owing to the features(high safety,inexpensive and environmental friendliness)of aqueous rechargeable Mg-ion batteries(ARMIBs),they have drawn extensive attention in the future energy storage systems.However,the poor M...Owing to the features(high safety,inexpensive and environmental friendliness)of aqueous rechargeable Mg-ion batteries(ARMIBs),they have drawn extensive attention in the future energy storage systems.However,the poor Mg^(2+)migration kinetics during the Mg^(2+)intercalation/extraction still hinders the progress of developing suitable cathode materials.Herein,a layered buserite Mg-Mn oxide(MMO)material with large interlayer space(~9.70A)and low-crystalline structure is studied as a high-performance cathode in ARMIBs.Compared with the counterpart,the Mg^(2+)migration kinetics of the MMO cathode can be enhanced by its unique structure(bigger interlayer spacing and low-crystalline structure).The layered buserite MMO as a high-performance ARMIBs cathode exhibits high Mg storage capacity(50 mAg^(-1):169.3 mAh g^(-1)),excellent rate capability(1000 mAg^(-1):98.3 mAh g^(-1)),and fast Mg^(2+)migration(an average diffusion coefficient:~4.21×10-^(10)cm^(2)s^(-1))in 0.5 M MgCl_(2)aqueous electrolyte.Moreover,the MMO-1//AC full battery achieved a high discharge capacity(100 mAg^(-1):111 mAh g^(-1)),and an ignored fading over 5000 cycles(1000 mAg^(-1)).Therefore,layered Mg-Mn oxide with large interlayer space may break a new path to develop the promising ARMIBs.展开更多
During the construction of subway tunnels,safety issues should not be ignored,so it is necessary to prevent and resolve the risk in time and accurately.However,there are some shortcomings in the research of risk asses...During the construction of subway tunnels,safety issues should not be ignored,so it is necessary to prevent and resolve the risk in time and accurately.However,there are some shortcomings in the research of risk assessment,such as the subjectivity of initial data or the lack of scientific evaluation model,in order to solve the problem,this paper relies on the Changping section of the Guanhui Intercity Metro,in order to establish a dynamic risk-warn-ing model for the construction process of subway tunnel with the CD-Bench composite method.First,a monitor-ing plan was equationted according to the specification requirements and the actual situation of the project,and based on this,an evaluation index system was established from five aspects:geological and support conditions,crown settlement,clearance convergence,and ground settlement and building settlement.Secondly,according to the established risk evaluation standards,the risk level of the index is determined by introducing extension theory and determining the combined weight of the index based on the distance function.Finally,feedback the corresponding risk-warning signals and take control measures.Through the application analysis shows that the model can alarm the risks during the tunnel construction process directly and timely,so the model is feasible and practical,and it is worthy of popularization and application in similar projects.展开更多
Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials,and thus,the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle...Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials,and thus,the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag+ ratios.Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays,and shifts to both Ag particles and released Ag^+ in 48 hr bioassays.Herein,as a continued study,the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically.The cytotoxicity and mechanisms of nanoAg colloids are dynamic throughout exposure and are derived from both Ag ions and particles.Ag accumulation by E.coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure,and thereafter mainly from intracellular Ag ions.Fe^3+ accelerates the oxidative dissolution of nano-Ag colloids,which results In decreasing amounts of Ag particles and particle-related toxicity.Na^+ stabilizes nano-Ag colloids,thereby decreasing the bioavailability of Ag particles and particle-related toxicity.Humic acid(HA) binds Ag^+ to form Ag^+-HA,decreasing ion-related toxicity and binding to the E.coli surface,decreasing particle-related toxicity.HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na^+ or Fe^3+.The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors,and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments.展开更多
The authors investigate the global existence and semiclassical limit of weak solutions to a sixth-order parabolic system,which is a quantum-corrected macroscopic model derived recently to simulate the quantum effects ...The authors investigate the global existence and semiclassical limit of weak solutions to a sixth-order parabolic system,which is a quantum-corrected macroscopic model derived recently to simulate the quantum effects in miniaturized semiconductor devices.展开更多
基金financially supported by the Fundamental Research Funds for the Central Universities(NO.2021CDJXDJH003)Guangdong National Technology Co.,Ltd.
文摘Owing to the features(high safety,inexpensive and environmental friendliness)of aqueous rechargeable Mg-ion batteries(ARMIBs),they have drawn extensive attention in the future energy storage systems.However,the poor Mg^(2+)migration kinetics during the Mg^(2+)intercalation/extraction still hinders the progress of developing suitable cathode materials.Herein,a layered buserite Mg-Mn oxide(MMO)material with large interlayer space(~9.70A)and low-crystalline structure is studied as a high-performance cathode in ARMIBs.Compared with the counterpart,the Mg^(2+)migration kinetics of the MMO cathode can be enhanced by its unique structure(bigger interlayer spacing and low-crystalline structure).The layered buserite MMO as a high-performance ARMIBs cathode exhibits high Mg storage capacity(50 mAg^(-1):169.3 mAh g^(-1)),excellent rate capability(1000 mAg^(-1):98.3 mAh g^(-1)),and fast Mg^(2+)migration(an average diffusion coefficient:~4.21×10-^(10)cm^(2)s^(-1))in 0.5 M MgCl_(2)aqueous electrolyte.Moreover,the MMO-1//AC full battery achieved a high discharge capacity(100 mAg^(-1):111 mAh g^(-1)),and an ignored fading over 5000 cycles(1000 mAg^(-1)).Therefore,layered Mg-Mn oxide with large interlayer space may break a new path to develop the promising ARMIBs.
基金The work is support by the National Natural Science Foundation of China:51668037.
文摘During the construction of subway tunnels,safety issues should not be ignored,so it is necessary to prevent and resolve the risk in time and accurately.However,there are some shortcomings in the research of risk assessment,such as the subjectivity of initial data or the lack of scientific evaluation model,in order to solve the problem,this paper relies on the Changping section of the Guanhui Intercity Metro,in order to establish a dynamic risk-warn-ing model for the construction process of subway tunnel with the CD-Bench composite method.First,a monitor-ing plan was equationted according to the specification requirements and the actual situation of the project,and based on this,an evaluation index system was established from five aspects:geological and support conditions,crown settlement,clearance convergence,and ground settlement and building settlement.Secondly,according to the established risk evaluation standards,the risk level of the index is determined by introducing extension theory and determining the combined weight of the index based on the distance function.Finally,feedback the corresponding risk-warning signals and take control measures.Through the application analysis shows that the model can alarm the risks during the tunnel construction process directly and timely,so the model is feasible and practical,and it is worthy of popularization and application in similar projects.
基金supported by the Joint Funds of the National Natural Science Foundation of China (No.U1804109)the State Key Laboratory of Motor Vehicle Biofuel Technology (No.KFKT2018006)+3 种基金the Scientific Research and Service Platform Fund of Henan Province (No.2016151)the Key Scientific and Technological Research Projects in Henan Province (No. 192102310305)the Foundation of Henan Educational Committee (No.19A330003)the Foundation of Nanyang Normal University (No.2018ZX023).
文摘Released Ag ions or/and Ag particles are believed to contribute to the cytotoxicity of Ag nanomaterials,and thus,the cytotoxicity and mechanism of Ag nanomaterials should be dynamic in water due to unfixed Ag particle:Ag+ ratios.Our recent research found that the cytotoxicity of PVP-Ag nanoparticles is attributable to Ag particles alone in 3 hr bioassays,and shifts to both Ag particles and released Ag^+ in 48 hr bioassays.Herein,as a continued study,the cytotoxicity and accumulation of 50 and 100 nm Ag colloids in Escherichia coli were determined dynamically.The cytotoxicity and mechanisms of nanoAg colloids are dynamic throughout exposure and are derived from both Ag ions and particles.Ag accumulation by E.coli is derived mainly from extracellular Ag particles during the initial 12 hr of exposure,and thereafter mainly from intracellular Ag ions.Fe^3+ accelerates the oxidative dissolution of nano-Ag colloids,which results In decreasing amounts of Ag particles and particle-related toxicity.Na^+ stabilizes nano-Ag colloids,thereby decreasing the bioavailability of Ag particles and particle-related toxicity.Humic acid(HA) binds Ag^+ to form Ag^+-HA,decreasing ion-related toxicity and binding to the E.coli surface,decreasing particle-related toxicity.HA in complex conditions showed a stronger relative contribution to toxicity and accumulation than Na^+ or Fe^3+.The results highlighted the cytotoxicity and mechanism of nano-Ag colloids are dynamic and affected by environmental factors,and therefore exposure duration and water chemistry should be seriously considered in environmental and health risk assessments.
基金Project supported by the National Natural Science Foundation of China (Nos. 10871112, 10771008)the Research Fund for the Doctoral Program of Higher Education of China (No. 20090005120009)+1 种基金 the Fundamental Research Funds for the Central Universities (No. BUPT2009RC0702)the Talents Scheme Funds of BUPT
文摘The authors investigate the global existence and semiclassical limit of weak solutions to a sixth-order parabolic system,which is a quantum-corrected macroscopic model derived recently to simulate the quantum effects in miniaturized semiconductor devices.