据新疆地震台网测定,2019年10月27日13时29分,新疆阿克苏地区乌什县发生MS5.0地震(以下简称乌什MS5.0地震),震中为41.21°N,78.82°E,震源深度11 km,当天18时52分再次发生MS4.5地震,地震类型为多震型。地震震源机制的确定,对于...据新疆地震台网测定,2019年10月27日13时29分,新疆阿克苏地区乌什县发生MS5.0地震(以下简称乌什MS5.0地震),震中为41.21°N,78.82°E,震源深度11 km,当天18时52分再次发生MS4.5地震,地震类型为多震型。地震震源机制的确定,对于研究地震的发震机制,孕震机理以及震后应力的分布,具有非常重要的意义[1-5]。早期的地震矩张量大都是由P波初动符号确定,如高国英等(1998)采用P波初动的方法计算1997年伽师强震群6级以上地震的震源机制解,确定了伽师震群的破裂面[6]。利用宽频带地震波形记录来反演地震矩张量可以避开P波初动求解震源机制的苛刻条件,可以得到整个地震破裂过程的信息。本文中利用目前较流行的CAP(Cut and Paste)方法快速计算了乌什MS5.0和MS4.5地震震源机制解,对于判定未来地震活动趋势具有重要意义,为震源区及其邻区的构造应力场积累了基础资料。展开更多
The effects of Ag on the microstructure and corrosion behavior of pre-soldering Sn-xAg lead-free solders,and on the formation of intermetallic layer of the solders with Cu substrate were investigated.The Ag contents(x...The effects of Ag on the microstructure and corrosion behavior of pre-soldering Sn-xAg lead-free solders,and on the formation of intermetallic layer of the solders with Cu substrate were investigated.The Ag contents(x)were 0,3.0,3.5,4.0,and5.0 wt.%.The Ag content played a role in the morphology of Ag3 Sn phase in the solders.The microstructure analysis showed that theβ-Sn phase was surrounded by eutectic networks in the 3.0 Ag and 3.5 Ag solders and large plate-like Ag3 Sn formed in the 4.0 Ag and5.0 Ag solders.Nonetheless,the Ag content slightly impacted the corrosion behavior of the as-cast solders as characterized using potentiodynamic polarization test.After soldering,only a single layer of a Cu6 Sn5 intermetallic compound formed at the Sn-xAg/Cu interface.By comparison,the Cu6 Sn5 intermetallic layer of the Ag-doped solders was thinner than that of the 0Ag solder.The fine Ag3 Sn particles in the eutectic networks precipitating in the 3.0 Ag and 3.5 Ag solders effectively hindered the growth of Cu6 Sn5 grains compared to large plate-like Ag3 Sn in the 4.0 and 5.0Ag solders.展开更多
Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium bat...Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium batteries,the evolution of anode materials has significantly promoted the development of lithium batteries.However,since conventional lithium batteries with graphite anodes cannot meet the ever-increasing demands in different application scenarios(such as electric vehicles and large-scale power supplies)which require high energy/power density and long cycle life,various improvement strategies and alternative anode materials have been exploited for better electrochemical performance.In this review,we detailedly introduced the characteristics and challenges of four representative anode materials for rechargeable lithium batteries,including graphite,Li_(4)Ti_(5)O_(12),silicon,and lithium metal.And some of the latest advances are summarized,which mainly contain the modification strategies of anode materials and partially involve the optimization of electrode/electrolyte interface.Finally,we make the conclusive comments and perspectives,and draw a development timeline on the four anode materials.This review aims to offer a good primer for newcomers in the lithium battery field and benefit the structure and material design of anodes for advanced rechargeable lithium batteries in the future.展开更多
The photocatalytic properties of CeO2-Nb2O5 photocatalysts in heterogeneous photocatalysis(under ultraviolet and visible radiation)and in Fenton-like process were reported.Methylene blue dye(MB)and phenol(Ph)were used...The photocatalytic properties of CeO2-Nb2O5 photocatalysts in heterogeneous photocatalysis(under ultraviolet and visible radiation)and in Fenton-like process were reported.Methylene blue dye(MB)and phenol(Ph)were used as models of pollutant molecules for these reactions,and the photocatalysts were characterized by X-ray diffraction(XRD),diffuse reflectance spectroscopy(DRS),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and thermally stimulated luminescence(TL).The results indicated that the addition of CeO2(0.3 wt%,1.0 wt%and 2.0 wt%)to Nb2O5 sensitized the resultant materials,increasing light absorption in the visible region.However,there is a suitable formulation of CeO2-Nb2O5 photocatalysts to improve each photocatalytic process.In heterogeneous photocatalysis,the addition of small CeO2 quantities to Nb2O5 was enough to improve the photocatalytic activity of CeO2-Nb2O5 photocatalysts(The best composition reported was CeO20.3 wt%.).The effectiveness of the catalyst was explained by the decrease in the number of trapping and luminescence centers in the conduction band of the material after the addition of CeO2 to Nb2O5,but a large amount of CeO2 decreased the number of trapping,luminescent and active centers to a large extent.Contrarily,in a Fenton-like process,the addition of CeO2 to Nb2O5 was favorable in all the proportions studied.(The best composition was 2.0 wt%CeO2.)In this case,the effectiveness was explained by the influence of the adsorption process(adsorption-triggered process),and the interactions between H2 O2 and Ce3+of the CeO2 in each photocatalyst thus formed surface peroxide species O22-,which induced the removal of the organic molecules under visible light.展开更多
文摘据新疆地震台网测定,2019年10月27日13时29分,新疆阿克苏地区乌什县发生MS5.0地震(以下简称乌什MS5.0地震),震中为41.21°N,78.82°E,震源深度11 km,当天18时52分再次发生MS4.5地震,地震类型为多震型。地震震源机制的确定,对于研究地震的发震机制,孕震机理以及震后应力的分布,具有非常重要的意义[1-5]。早期的地震矩张量大都是由P波初动符号确定,如高国英等(1998)采用P波初动的方法计算1997年伽师强震群6级以上地震的震源机制解,确定了伽师震群的破裂面[6]。利用宽频带地震波形记录来反演地震矩张量可以避开P波初动求解震源机制的苛刻条件,可以得到整个地震破裂过程的信息。本文中利用目前较流行的CAP(Cut and Paste)方法快速计算了乌什MS5.0和MS4.5地震震源机制解,对于判定未来地震活动趋势具有重要意义,为震源区及其邻区的构造应力场积累了基础资料。
文摘The effects of Ag on the microstructure and corrosion behavior of pre-soldering Sn-xAg lead-free solders,and on the formation of intermetallic layer of the solders with Cu substrate were investigated.The Ag contents(x)were 0,3.0,3.5,4.0,and5.0 wt.%.The Ag content played a role in the morphology of Ag3 Sn phase in the solders.The microstructure analysis showed that theβ-Sn phase was surrounded by eutectic networks in the 3.0 Ag and 3.5 Ag solders and large plate-like Ag3 Sn formed in the 4.0 Ag and5.0 Ag solders.Nonetheless,the Ag content slightly impacted the corrosion behavior of the as-cast solders as characterized using potentiodynamic polarization test.After soldering,only a single layer of a Cu6 Sn5 intermetallic compound formed at the Sn-xAg/Cu interface.By comparison,the Cu6 Sn5 intermetallic layer of the Ag-doped solders was thinner than that of the 0Ag solder.The fine Ag3 Sn particles in the eutectic networks precipitating in the 3.0 Ag and 3.5 Ag solders effectively hindered the growth of Cu6 Sn5 grains compared to large plate-like Ag3 Sn in the 4.0 and 5.0Ag solders.
基金supported by grants from the Natural Science Foundation of Jiangsu Province(BK20180098)the Open Research Fund of National Laboratory of Solid State Microstructures of Nanjing University(M32045&M33042)。
文摘Rechargeable lithium batteries have been widely regarded as a revolutionary technology to store renewable energy sources and extensively researched in the recent several decades.As an indispensable part of lithium batteries,the evolution of anode materials has significantly promoted the development of lithium batteries.However,since conventional lithium batteries with graphite anodes cannot meet the ever-increasing demands in different application scenarios(such as electric vehicles and large-scale power supplies)which require high energy/power density and long cycle life,various improvement strategies and alternative anode materials have been exploited for better electrochemical performance.In this review,we detailedly introduced the characteristics and challenges of four representative anode materials for rechargeable lithium batteries,including graphite,Li_(4)Ti_(5)O_(12),silicon,and lithium metal.And some of the latest advances are summarized,which mainly contain the modification strategies of anode materials and partially involve the optimization of electrode/electrolyte interface.Finally,we make the conclusive comments and perspectives,and draw a development timeline on the four anode materials.This review aims to offer a good primer for newcomers in the lithium battery field and benefit the structure and material design of anodes for advanced rechargeable lithium batteries in the future.
基金the Sao Paulo Research Foundation(FAPESP)(for the financial support,Grant numbers 2014/24940-5,and 2017/01462-9)the Brazilian National Council for Scientific Development(CNPq)for the fellowship given to Nathalia P.Ferraz,and to the Brazilian Metals and Mining Company(CBMM).
文摘The photocatalytic properties of CeO2-Nb2O5 photocatalysts in heterogeneous photocatalysis(under ultraviolet and visible radiation)and in Fenton-like process were reported.Methylene blue dye(MB)and phenol(Ph)were used as models of pollutant molecules for these reactions,and the photocatalysts were characterized by X-ray diffraction(XRD),diffuse reflectance spectroscopy(DRS),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and thermally stimulated luminescence(TL).The results indicated that the addition of CeO2(0.3 wt%,1.0 wt%and 2.0 wt%)to Nb2O5 sensitized the resultant materials,increasing light absorption in the visible region.However,there is a suitable formulation of CeO2-Nb2O5 photocatalysts to improve each photocatalytic process.In heterogeneous photocatalysis,the addition of small CeO2 quantities to Nb2O5 was enough to improve the photocatalytic activity of CeO2-Nb2O5 photocatalysts(The best composition reported was CeO20.3 wt%.).The effectiveness of the catalyst was explained by the decrease in the number of trapping and luminescence centers in the conduction band of the material after the addition of CeO2 to Nb2O5,but a large amount of CeO2 decreased the number of trapping,luminescent and active centers to a large extent.Contrarily,in a Fenton-like process,the addition of CeO2 to Nb2O5 was favorable in all the proportions studied.(The best composition was 2.0 wt%CeO2.)In this case,the effectiveness was explained by the influence of the adsorption process(adsorption-triggered process),and the interactions between H2 O2 and Ce3+of the CeO2 in each photocatalyst thus formed surface peroxide species O22-,which induced the removal of the organic molecules under visible light.
