Aging treatment and various heat input conditions and mechanical properties of TIG welded 606I-T6 alloy joints were adopted to investigate the microstructural evolution by microstructural observations, microhardness t...Aging treatment and various heat input conditions and mechanical properties of TIG welded 606I-T6 alloy joints were adopted to investigate the microstructural evolution by microstructural observations, microhardness tests, and tensile tests. With an increase in heat input, the width of the heat-affected zone （HAZ） increases and grains in the fusion zone （FZ） coarsen. Moreover, the hardness of the HAZ decreases, whereas that of the FZ decreases initially and then increases with an increase in heat input. Low heat input results in the low ultimate tensile strength of the welded joints due to the presence of partial penetrations and pores in the welded joints. After a simple artificial aging treatment at 175℃ for 8 h, the microstructure of the welded joints changes slightly. The mechanical properties of the welded joints enhance significantly after the aging process as few precipitates distribute in the welded seam.展开更多
SnO_(2) is considered to be a promising candidate as anode material for lithium ion batteries,due to its high theoretical specific capacity(1494 mAh·g^(-1)).Nevertheless,SnO_(2)-based anodes suffer from poor elec...SnO_(2) is considered to be a promising candidate as anode material for lithium ion batteries,due to its high theoretical specific capacity(1494 mAh·g^(-1)).Nevertheless,SnO_(2)-based anodes suffer from poor electronic conductivity and serious volume variation(300%)during lithiation/delithiation process,leading to fast capacity fading.To solve these problems,SnO_(2) quantum dots modified N-doped carbon spheres(SnO_(2) QDs@N-C)are fabricated by facile hydrolysis process of SnCl2,accompanied with the polymerization of polypyrrole(PPy),followed by a calcination method.When used as anodes for lithium ion batteries,SnO_(2) QDs@N-C exhibits high discharge capacity,superior rate properties as well as good cyclability.The carbon matrix completely encapsulates the SnO_(2) quantum dots,preventing the aggregation and volume change during cycling.Furthermore,the high N content produces abundant defects in carbon matrix.It is worth noting that SnO_(2) QDs@N-C shows excellent capacitive contribution properties,which may be due to the ultra-small size of SnO_(2) and high conductivity of the carbon matrix.展开更多
Transition metal-rare earth oxide catalysts had the ability to catalyze ammonia decomposition according to recent years'scientific reports.However,most of those catalysts had their own limitations:the catalytic ac...Transition metal-rare earth oxide catalysts had the ability to catalyze ammonia decomposition according to recent years'scientific reports.However,most of those catalysts had their own limitations:the catalytic activity was poor,and/or the active species could not clearly be iden tified.Here we report the Co_(a)Sm_(b)O_(x) catalysts with good dispersi on,con trollable content,and excelle nt catalytic performs nee for amm onia decomposition.The various content catalysts were syn thesized by aerosol-assisted self-assembly approach.These catalysts had high dispersion and great morphology according to the images of the transmission electron microscope(TEM)and the seanning electron microscope(SEM).The temperature-programmed reduction by hydrogen(Hq-TPR)and in-situ X-ray diffraction(XRD)results indicated that the interaction between cobalt oxide and samarium oxide influenced the redox properties of cobalt oxide.Combined with in-situ Raman,we found that Co0 was an active species of the Co_(a)Sm_(b)O_(x) catalysts in ammonia decomposition.Moreover,the temperature-programmed desorption of NH_(3)(NH_(3)-TPD)data illustrated that the addition of Sm was beneficial to the adsorption of NH3.In general,we successfully obtained the Co_(a)Sm_(b)O_(x) catalyst with high activity and good stability.More im-porta ntly,we have identified the structure-function relation ship of catalysts by exploring the active species in the reaction process.展开更多
基金financially supported by the Natural Science Foundation Project of Chongqing City (No.cstc2012jjA50002)
文摘Aging treatment and various heat input conditions and mechanical properties of TIG welded 606I-T6 alloy joints were adopted to investigate the microstructural evolution by microstructural observations, microhardness tests, and tensile tests. With an increase in heat input, the width of the heat-affected zone （HAZ） increases and grains in the fusion zone （FZ） coarsen. Moreover, the hardness of the HAZ decreases, whereas that of the FZ decreases initially and then increases with an increase in heat input. Low heat input results in the low ultimate tensile strength of the welded joints due to the presence of partial penetrations and pores in the welded joints. After a simple artificial aging treatment at 175℃ for 8 h, the microstructure of the welded joints changes slightly. The mechanical properties of the welded joints enhance significantly after the aging process as few precipitates distribute in the welded seam.
基金financially supported by the National Natural Science Foundation of China(Nos.51702138 and 21817056)the Natural Science Foundation of Jiangsu Province(Nos.BK20160213 and BK20170239)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(No.KYCX202358)。
文摘SnO_(2) is considered to be a promising candidate as anode material for lithium ion batteries,due to its high theoretical specific capacity(1494 mAh·g^(-1)).Nevertheless,SnO_(2)-based anodes suffer from poor electronic conductivity and serious volume variation(300%)during lithiation/delithiation process,leading to fast capacity fading.To solve these problems,SnO_(2) quantum dots modified N-doped carbon spheres(SnO_(2) QDs@N-C)are fabricated by facile hydrolysis process of SnCl2,accompanied with the polymerization of polypyrrole(PPy),followed by a calcination method.When used as anodes for lithium ion batteries,SnO_(2) QDs@N-C exhibits high discharge capacity,superior rate properties as well as good cyclability.The carbon matrix completely encapsulates the SnO_(2) quantum dots,preventing the aggregation and volume change during cycling.Furthermore,the high N content produces abundant defects in carbon matrix.It is worth noting that SnO_(2) QDs@N-C shows excellent capacitive contribution properties,which may be due to the ultra-small size of SnO_(2) and high conductivity of the carbon matrix.
基金supported from the National Natural Science Foundation of China(Nos.21771117,21805167 and 22075166)the Taishan Scholar Project of Shandong Province of China and the Young Scholars Program of Shandong University(No.11190089964158)。
文摘Transition metal-rare earth oxide catalysts had the ability to catalyze ammonia decomposition according to recent years'scientific reports.However,most of those catalysts had their own limitations:the catalytic activity was poor,and/or the active species could not clearly be iden tified.Here we report the Co_(a)Sm_(b)O_(x) catalysts with good dispersi on,con trollable content,and excelle nt catalytic performs nee for amm onia decomposition.The various content catalysts were syn thesized by aerosol-assisted self-assembly approach.These catalysts had high dispersion and great morphology according to the images of the transmission electron microscope(TEM)and the seanning electron microscope(SEM).The temperature-programmed reduction by hydrogen(Hq-TPR)and in-situ X-ray diffraction(XRD)results indicated that the interaction between cobalt oxide and samarium oxide influenced the redox properties of cobalt oxide.Combined with in-situ Raman,we found that Co0 was an active species of the Co_(a)Sm_(b)O_(x) catalysts in ammonia decomposition.Moreover,the temperature-programmed desorption of NH_(3)(NH_(3)-TPD)data illustrated that the addition of Sm was beneficial to the adsorption of NH3.In general,we successfully obtained the Co_(a)Sm_(b)O_(x) catalyst with high activity and good stability.More im-porta ntly,we have identified the structure-function relation ship of catalysts by exploring the active species in the reaction process.
