Excess greenhouse gas emissions,primarily carbon dioxide(CO_(2)),have caused major environmental concerns worldwide.The electroreduction of CO_(2)into valuable chemicals using renewable energy is an ecofriendly approa...Excess greenhouse gas emissions,primarily carbon dioxide(CO_(2)),have caused major environmental concerns worldwide.The electroreduction of CO_(2)into valuable chemicals using renewable energy is an ecofriendly approach to achieve carbon neutrality.In this regard,copper(Cu)has attracted considerable attention as the only known metallic catalyst available for converting CO_(2)to high-value multicarbon(C_(2+))products.The production of C_(2+)involves complicated C-C coupling steps and thus imposes high demands on intermediate regulation.In this review,we discuss multiple strategies for modulating intermediates to facilitate C_(2+)formation on Cu-based catalysts.Furthermore,several sophisticated in situ characterization techniques are outlined for elucidating the mechanism of C-C coupling.Lastly,the challenges and future directions of CO_(2)electroreduction to C_(2+)are envisioned.展开更多
I.THEORY The Hamiltonian of rare earth ions can be written as where （?）<sub>Coul</sub> is the Coulomb interaction, （?）<sub>s·o</sub>, the spin-orbit interaction, （?）<sub>Ca<...I.THEORY The Hamiltonian of rare earth ions can be written as where （?）<sub>Coul</sub> is the Coulomb interaction, （?）<sub>s·o</sub>, the spin-orbit interaction, （?）<sub>Ca</sub>, Casimir operator interaction in the interaction of different configurations in Coulomb interaction, and （?）<sub>cf</sub> is ligand field interaction. A method to treat the rare earth ions is to diagonalize （?）<sub>Coul</sub>, （?）<sub>s.o</sub> and （?）<sub>Ca</sub>, in （1） simultaneously and then to determine the eigenfunction of "展开更多
Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of ...Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of car body structure damage and train derailment will increase.Herein,a four-stage rigid-flexible coupling finite element model of the coupler is established considering the coupler buckling load.The influence of the coupler buckling load on the train longitudinal-vertical-hori-zontal buckling behavior was studied,and the mechanism of the train horizontal buckling instability in train collisions was revealed.Analysis results show that an intermediate coupler should be designed to ensure that the actual buckling load is less than the compressive load when the car body structure begins to deform plastically.The actual buckling load of the coupler and the asymmetry of the structural strength of the car body in the lateral direction are two important influencing factors for the lateral buckling of a train collision.If the strength of the two sides of the car body structure in the lateral direction is asymmetrical,the deformation on the weaker side will be larger,and the end of the car body will begin to deflect under the action of the coupler force,which in turn causes the train to undergo sawtooth buckling.展开更多
To obtain new functional aromatic polymer materiul. 3,3＇-biacenaphthene, which is used as macromolecule intermediate of,funcrion aromatic polymer material, was synthesized through the coupling reaction of acenaphthen...To obtain new functional aromatic polymer materiul. 3,3＇-biacenaphthene, which is used as macromolecule intermediate of,funcrion aromatic polymer material, was synthesized through the coupling reaction of acenaphthene catalyzing by ionic liquid （[bmim]CI/FeCl3） at mild reaction condition. Pure 3,3＇-biacenaphthene was obtained hy recrystalling and column chromatography from the reaction mixture and was determined by GC/MS, SHNMR arid FTIR analysis. The influence of various reaction conditions on the yield of 3,3＇-biacenaphthene were studied by GC analysis. The result shows that the optimun synthesis conditions of the coupling reaction are, as following： the molar ratio of FeCl3 to [BmimlCl being 3, the mole ratio of FeCl3 in [Bmim]Cl/FeCl3 to acenaphthene being 4. the reaction temperamre being 20 ℃ the reaction time being 4h and the solvent of the reaction system being PhNO2 Under those conditions, the yield of the 3.3＇-biacenaphthene will be 48.71% and selectivity, of that will be 78.56 %. Farther more, [bmim]Cl/FeCl3 has no pollution to environments and can be reused.展开更多
基金support of the National Natural Science Foundation of China(Nos.51972223,51932005 and 22109116)the Natural Science Foundation of Tianjin(No.20JCYBJC01550)+1 种基金the Fundamental Research Funds for the Cen-tral Universitiesthe Haihe Laboratory of Sustainable Chemical Transformations.
文摘Excess greenhouse gas emissions,primarily carbon dioxide(CO_(2)),have caused major environmental concerns worldwide.The electroreduction of CO_(2)into valuable chemicals using renewable energy is an ecofriendly approach to achieve carbon neutrality.In this regard,copper(Cu)has attracted considerable attention as the only known metallic catalyst available for converting CO_(2)to high-value multicarbon(C_(2+))products.The production of C_(2+)involves complicated C-C coupling steps and thus imposes high demands on intermediate regulation.In this review,we discuss multiple strategies for modulating intermediates to facilitate C_(2+)formation on Cu-based catalysts.Furthermore,several sophisticated in situ characterization techniques are outlined for elucidating the mechanism of C-C coupling.Lastly,the challenges and future directions of CO_(2)electroreduction to C_(2+)are envisioned.
文摘I.THEORY The Hamiltonian of rare earth ions can be written as where （?）<sub>Coul</sub> is the Coulomb interaction, （?）<sub>s·o</sub>, the spin-orbit interaction, （?）<sub>Ca</sub>, Casimir operator interaction in the interaction of different configurations in Coulomb interaction, and （?）<sub>cf</sub> is ligand field interaction. A method to treat the rare earth ions is to diagonalize （?）<sub>Coul</sub>, （?）<sub>s.o</sub> and （?）<sub>Ca</sub>, in （1） simultaneously and then to determine the eigenfunction of "
基金This work was supported by the National Natural Science Foundation of China(No.52172409)Sichuan Outstanding Youth Fund(No.2022JDJQ0025).
文摘Rail vehicles generate huge longitudinal impact loads in collisions.If unreasonable matching exists between the compressive strength of the intermediate coupler and the structural strength of the car body,the risk of car body structure damage and train derailment will increase.Herein,a four-stage rigid-flexible coupling finite element model of the coupler is established considering the coupler buckling load.The influence of the coupler buckling load on the train longitudinal-vertical-hori-zontal buckling behavior was studied,and the mechanism of the train horizontal buckling instability in train collisions was revealed.Analysis results show that an intermediate coupler should be designed to ensure that the actual buckling load is less than the compressive load when the car body structure begins to deform plastically.The actual buckling load of the coupler and the asymmetry of the structural strength of the car body in the lateral direction are two important influencing factors for the lateral buckling of a train collision.If the strength of the two sides of the car body structure in the lateral direction is asymmetrical,the deformation on the weaker side will be larger,and the end of the car body will begin to deflect under the action of the coupler force,which in turn causes the train to undergo sawtooth buckling.
基金National Natural Science Foundation of China (No. 20207003)
文摘To obtain new functional aromatic polymer materiul. 3,3＇-biacenaphthene, which is used as macromolecule intermediate of,funcrion aromatic polymer material, was synthesized through the coupling reaction of acenaphthene catalyzing by ionic liquid （[bmim]CI/FeCl3） at mild reaction condition. Pure 3,3＇-biacenaphthene was obtained hy recrystalling and column chromatography from the reaction mixture and was determined by GC/MS, SHNMR arid FTIR analysis. The influence of various reaction conditions on the yield of 3,3＇-biacenaphthene were studied by GC analysis. The result shows that the optimun synthesis conditions of the coupling reaction are, as following： the molar ratio of FeCl3 to [BmimlCl being 3, the mole ratio of FeCl3 in [Bmim]Cl/FeCl3 to acenaphthene being 4. the reaction temperamre being 20 ℃ the reaction time being 4h and the solvent of the reaction system being PhNO2 Under those conditions, the yield of the 3.3＇-biacenaphthene will be 48.71% and selectivity, of that will be 78.56 %. Farther more, [bmim]Cl/FeCl3 has no pollution to environments and can be reused.
