In order to provide a reference for the correct forecasting of short-term heavy rainfall and better disaster prevention and mitigation services in Shanxi Province, China, it is very important to carry out systematic r...In order to provide a reference for the correct forecasting of short-term heavy rainfall and better disaster prevention and mitigation services in Shanxi Province, China, it is very important to carry out systematic research on short-term heavy precipitation events in Shanxi Province. Based on hourly precipitation data during the flood season (May to September) from 109 meteorological stations in Shanxi, China in 1980-2015, the temporal and spatial variation characteristics of short-time heavy rainfall during the flood season are analyzed by using wavelet analysis and Mann-Kendall test. The results show that the short-time heavy rainfall in the flood season in Shanxi Province is mainly at the grade of 20 - 30 mm/h, with an average of 97 stations having short-time heavy rainfall each year, accounting for 89% of the total stations. The short-time heavy rainfall mainly concentrated in July and August, and the maximal rain intensity in history appeared at 23 - 24 on June 17, 1991 in Yongji, Shanxi is 91.7 mm/h. During the flood season, the short-time heavy rainfalls always occur at 16 - 18 pm, and have slightly different concentrated time in different months. The main peaks of June, July and August are at 16, 17 and 18 respectively, postponed for one hour. Short-time heavy rainfall overall has the distribution that the south is more than the north and the east less than the west in Shanxi area. In the last 36 years, short-time heavy rainfall has a slight increasing trend in Shanxi, but not significant. There is a clear 4-year period of oscillation and inter-decadal variation. It has a good correlation between the total precipitation and times of short-time heavy rainfall during the flood season.展开更多
Recently,metal-organic framework(MOF)-based multienzyme systems integrating different functional natural enzymes and/or nanomaterial-basedartificial enzymes are attracting increasing attention due to their high cataly...Recently,metal-organic framework(MOF)-based multienzyme systems integrating different functional natural enzymes and/or nanomaterial-basedartificial enzymes are attracting increasing attention due to their high catalytic efficiency and promising application in sensing.Simpleand controllable integration of enzymes or nanozymes within MOFs is crucial for achieving efficient cascade catalysis and high stability.Here,we report a facile electrochemical assisted biomimetic mineralization strategy to prepare an artificial multienzyme system for efficient electrochemicaldetection of biomolecules.By using the G0x@Cu-MOF/copper foam(G0x@Cu-MOF/CF)architecture as a proof of concept,efficientenzyme immobilization and cascade catalysis were achieved by in situ encapsulation of glucose oxidase(GOx)within MOFs layer grown onthree-dimensional(3D)porous conducting CF via a facile one-step electrochemical assisted biomimetic mineralization strategy.Due to thebio-electrocatalytic cascade reaction mechanism,this well-designed GOx@Cu-MOF modified electrode exhibited superior catalytic activityand thermal stability for glucose sensing.Notably,the activity of GOx@Cu-MOF/CF still remained at ca.80%after being incubated at 80℃.In sharp contrast,the activity of the unprotected electrode was reduced to the original 10%after the same treatment.The design strategypresented here may be useful in fabricating highly stable enzyme@MOF composites applied for efficient photothermal therapy and otherplatform under high temperature.展开更多
Three imidazole-modified Ag-polyoxovanadates frameworks(APFs)with a controllable molar ratio of Ag+to polyoxovanadates(POVs)[Ag(IM)_(2)]_(2)V_(4)O_(12)·2Ag(IM)_(2)(APF-1),[Ag_(2)(1-eIM)_(4)]_(2)[Ag(1-eIM)_(2)]_(3...Three imidazole-modified Ag-polyoxovanadates frameworks(APFs)with a controllable molar ratio of Ag+to polyoxovanadates(POVs)[Ag(IM)_(2)]_(2)V_(4)O_(12)·2Ag(IM)_(2)(APF-1),[Ag_(2)(1-eIM)_(4)]_(2)[Ag(1-eIM)_(2)]_(3)·2Ag(1-eIM)_(2)·3(1-HeIM)[V_(10)O_(28)]_(2)(APF-2)and[Ag(1-pIM)_(2)]_(3)[HV_(10)O_(28)]·2Ag(1-pIM)_(2)·2H_(2)O(APF-3)(IM=imida-zole;1-eIM=1-ethylimidazole and 1-pIM=1-propylimidazole)have been successfully achieved by self-assembly of POVs,Ag+cations,and three different imidazole derivatives.Interestingly,the molar ratios of Ag+to POVs vary from 4:1,4.5:1 to 5:1 by changing the vanadium resources and imidazole deriva-tives.Notably,the coordination environment of Ag+cations and the structure of POVs in the APFs are also different.Specifically,for APF-1,the four Ag atoms adopt three-coordinated and four-coordinated geometries,respectively,and Ag-imidazole complexes and[V_(4)O 1_(2)]_(4)−cluster form the one-dimensional polymeric chains.While Ag atoms in APF-2 and APF-3 exhibit two-,four-and five-coordinated geome-tries for APF-2,four-,five-and six-coordinated geometries for APF-3,respectively.These Ag+cations and decavanadate clusters are assembled into the 2D supramolecular structure through the Ag-O bonds and Ag…Ag argentophilic interaction.Remarkably,thus-obtained APF-2 can serve as powerful efficient hetero-geneous catalyst for construction of C–N bond and detoxification of simulant sulfur mustard(yields up to 99%),which enable successful recycling for three cycles with remained catalytic activities and structure stability.展开更多
文摘In order to provide a reference for the correct forecasting of short-term heavy rainfall and better disaster prevention and mitigation services in Shanxi Province, China, it is very important to carry out systematic research on short-term heavy precipitation events in Shanxi Province. Based on hourly precipitation data during the flood season (May to September) from 109 meteorological stations in Shanxi, China in 1980-2015, the temporal and spatial variation characteristics of short-time heavy rainfall during the flood season are analyzed by using wavelet analysis and Mann-Kendall test. The results show that the short-time heavy rainfall in the flood season in Shanxi Province is mainly at the grade of 20 - 30 mm/h, with an average of 97 stations having short-time heavy rainfall each year, accounting for 89% of the total stations. The short-time heavy rainfall mainly concentrated in July and August, and the maximal rain intensity in history appeared at 23 - 24 on June 17, 1991 in Yongji, Shanxi is 91.7 mm/h. During the flood season, the short-time heavy rainfalls always occur at 16 - 18 pm, and have slightly different concentrated time in different months. The main peaks of June, July and August are at 16, 17 and 18 respectively, postponed for one hour. Short-time heavy rainfall overall has the distribution that the south is more than the north and the east less than the west in Shanxi area. In the last 36 years, short-time heavy rainfall has a slight increasing trend in Shanxi, but not significant. There is a clear 4-year period of oscillation and inter-decadal variation. It has a good correlation between the total precipitation and times of short-time heavy rainfall during the flood season.
基金This work was supported by the National Key Research and Development Program of China(Nos.2017YFA0206500 and 2017YFA0206801)the National Basic Research Program of China(No.2015CB932301)the National Natural Science Foundation of China(Nos.21671163,21721001,and J1310024).
文摘Recently,metal-organic framework(MOF)-based multienzyme systems integrating different functional natural enzymes and/or nanomaterial-basedartificial enzymes are attracting increasing attention due to their high catalytic efficiency and promising application in sensing.Simpleand controllable integration of enzymes or nanozymes within MOFs is crucial for achieving efficient cascade catalysis and high stability.Here,we report a facile electrochemical assisted biomimetic mineralization strategy to prepare an artificial multienzyme system for efficient electrochemicaldetection of biomolecules.By using the G0x@Cu-MOF/copper foam(G0x@Cu-MOF/CF)architecture as a proof of concept,efficientenzyme immobilization and cascade catalysis were achieved by in situ encapsulation of glucose oxidase(GOx)within MOFs layer grown onthree-dimensional(3D)porous conducting CF via a facile one-step electrochemical assisted biomimetic mineralization strategy.Due to thebio-electrocatalytic cascade reaction mechanism,this well-designed GOx@Cu-MOF modified electrode exhibited superior catalytic activityand thermal stability for glucose sensing.Notably,the activity of GOx@Cu-MOF/CF still remained at ca.80%after being incubated at 80℃.In sharp contrast,the activity of the unprotected electrode was reduced to the original 10%after the same treatment.The design strategypresented here may be useful in fabricating highly stable enzyme@MOF composites applied for efficient photothermal therapy and otherplatform under high temperature.
基金supported by the National Natu-ral Science Foundation of China(Nos.21871125,21871026 and 22001034)the Natural Science Foundation of Shandong Province,China(Nos.ZR2019MB043 and ZR2019QB022)the Construction Project of Quality Curriculum for Postgraduate Education of Shandong Province(No.SDYKC19057).
文摘Three imidazole-modified Ag-polyoxovanadates frameworks(APFs)with a controllable molar ratio of Ag+to polyoxovanadates(POVs)[Ag(IM)_(2)]_(2)V_(4)O_(12)·2Ag(IM)_(2)(APF-1),[Ag_(2)(1-eIM)_(4)]_(2)[Ag(1-eIM)_(2)]_(3)·2Ag(1-eIM)_(2)·3(1-HeIM)[V_(10)O_(28)]_(2)(APF-2)and[Ag(1-pIM)_(2)]_(3)[HV_(10)O_(28)]·2Ag(1-pIM)_(2)·2H_(2)O(APF-3)(IM=imida-zole;1-eIM=1-ethylimidazole and 1-pIM=1-propylimidazole)have been successfully achieved by self-assembly of POVs,Ag+cations,and three different imidazole derivatives.Interestingly,the molar ratios of Ag+to POVs vary from 4:1,4.5:1 to 5:1 by changing the vanadium resources and imidazole deriva-tives.Notably,the coordination environment of Ag+cations and the structure of POVs in the APFs are also different.Specifically,for APF-1,the four Ag atoms adopt three-coordinated and four-coordinated geometries,respectively,and Ag-imidazole complexes and[V_(4)O 1_(2)]_(4)−cluster form the one-dimensional polymeric chains.While Ag atoms in APF-2 and APF-3 exhibit two-,four-and five-coordinated geome-tries for APF-2,four-,five-and six-coordinated geometries for APF-3,respectively.These Ag+cations and decavanadate clusters are assembled into the 2D supramolecular structure through the Ag-O bonds and Ag…Ag argentophilic interaction.Remarkably,thus-obtained APF-2 can serve as powerful efficient hetero-geneous catalyst for construction of C–N bond and detoxification of simulant sulfur mustard(yields up to 99%),which enable successful recycling for three cycles with remained catalytic activities and structure stability.
