Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesi...Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.展开更多
Organic carbon(OC),element carbon(EC)and 8 car-bon fractions(OC1,OC2,OC3,OC4,EC1,EC2,EC3 and py rolytic carbon(OP))in PM2.s samples collected in Tianjin ur-ban area during January to April,2014 were analyzed with ther...Organic carbon(OC),element carbon(EC)and 8 car-bon fractions(OC1,OC2,OC3,OC4,EC1,EC2,EC3 and py rolytic carbon(OP))in PM2.s samples collected in Tianjin ur-ban area during January to April,2014 were analyzed with thermal light reflection method.The result showed that the concentrations of OC and EC in PM2.s were(18.7±9.9),(3.9±2.6)μg/m3,respectively,which accounting for 18.0 of PM2.s mass concentrations.Temporal variability of OC and EC was consistent,they were higher in the spring festival and heating season,and lower in the non heating season.The cor relation of carbon fractions were analyzed by SPSS 20.0,which illustrating the tight relationship between OC1-OC4 and ECI EC3,and suggesting that these constituents were derived from the same primary emission source or they were influenced by similar secondary processes in the atmosphere.The principal component analysis(PCA)showed that coal combus-tion,biomass burning and motor vehicle exhaust were three main sources of OC and EC in PM2.5 in Tianjin urban area.展开更多
基金Project(42076043) supported by the National Natural Science Foundation of ChinaProject(ZR2023ZD31) supported by the Major Basic Research Project of Natural Science Foundation of Shandong Province,ChinaProject(2023VEA0007) supported by the Chinese Academy of Sciences President’s International Fellowship Initiative。
文摘Corrosion caused by sulfate-reducing prokaryotes(SRP)is an important cause of magnesium alloy anode failure in oil pipeline.In this study,the effects of Desulfovibrio sp.HQM3 on the corrosion behavior of AZ31B magnesium alloy anode in organic carbon sources with different contents in simulated tidal flat environment were analyzed using weight loss test,surface analysis and electrochemical analysis technologies.The results showed that the weight loss rate of coupons in low carbon sources contents(0%,1%,10%)was higher than that in 100%carbon sources.Electrochemical analyses showed that the corrosion current density(J_(corr))under low carbon sources contents was larger,while the charge transfer resistance(R_(ct))was lower,leading to a higher corrosion rate compared to those under 100%carbon sources content.Observations from scanning electron microscopy(SEM)and confocal laser scanning microscopy(CLSM)revealed more severe pitting corrosion on the alloy surface in the absence of carbon sources.In addition,a large number of nanowires were observed between bacteria on the alloy surface using SEM.Combined with thermodynamic calculations,it was demonstrated that the corrosion of coupons by Desulfovibrio sp.HQM3 in the absence of carbon sources was achieved through extracellular electron transfer.
文摘Organic carbon(OC),element carbon(EC)and 8 car-bon fractions(OC1,OC2,OC3,OC4,EC1,EC2,EC3 and py rolytic carbon(OP))in PM2.s samples collected in Tianjin ur-ban area during January to April,2014 were analyzed with thermal light reflection method.The result showed that the concentrations of OC and EC in PM2.s were(18.7±9.9),(3.9±2.6)μg/m3,respectively,which accounting for 18.0 of PM2.s mass concentrations.Temporal variability of OC and EC was consistent,they were higher in the spring festival and heating season,and lower in the non heating season.The cor relation of carbon fractions were analyzed by SPSS 20.0,which illustrating the tight relationship between OC1-OC4 and ECI EC3,and suggesting that these constituents were derived from the same primary emission source or they were influenced by similar secondary processes in the atmosphere.The principal component analysis(PCA)showed that coal combus-tion,biomass burning and motor vehicle exhaust were three main sources of OC and EC in PM2.5 in Tianjin urban area.
