In order to improve the seismic performance, deformation ability and ultimate load-carrying capacity of columns with rectangular cross section, engineered cementitious composite （ECC） is introduced to partially subs...In order to improve the seismic performance, deformation ability and ultimate load-carrying capacity of columns with rectangular cross section, engineered cementitious composite （ECC） is introduced to partially substitute concrete in the edge zone of reinforced concrete columns and form reinforced ECC/concrete composite columns. Firstly, based on the assumption of plane remaining plane and the simplified constitutive models, the calculation method of the load-carrying capacity of reinforced ECC/concrete columns is proposed. The stress and strain distribu- tions and crack propagation of the composite columns in different states of eccentric compressive loading are ana- lyzed. Then, nonlinear finite element analysis is conducted to study the mechanical performance of reinforced ECC/concrete composite columns with rectangular cross section. It is found that the simulation results are in good agreement with the theoretical results, indicating that the proposed method for calculating the load-carrying capacity of concrete/ECC composite columns is valid. Finally, based on the proposed method, the effects of ECC thickness, com- pressive strength of concrete and longitudinal reinforcement ratio on the mechanical performance of reinforced ECC/ concrete composite columns are analyzed. Calculation results indicate that increasing the thickness of ECC layer or longitudinal reinforcement ratio can effectively increase the ultimate load-carrying capacity of the composite column with both small and large eccentricity, but increasing the strength of concrete can only increase the ultimate Ioad- carrying capacity of the composite column with small eccentricity.展开更多
Electrochemical oxidation of 4-methyl catechol（1a） is investigated in the presence of 1,3-indandione（3）as nucleophile in phosphate buffer solution（0.2 mol/L,pH 6） mixed with ethanol as organic green solvent（50...Electrochemical oxidation of 4-methyl catechol（1a） is investigated in the presence of 1,3-indandione（3）as nucleophile in phosphate buffer solution（0.2 mol/L,pH 6） mixed with ethanol as organic green solvent（50/50） using cyclic voltammetry and controlled-potential coulometry.The results indicated thatquinones derived from electro-oxidation of 1a,participated in a 1,4-Michael addition reaction with1,3-indandione（3） under ECCE mechanism.In this direction,a new bis-quinone was synthesized in high yield and good purity using a facile and convenient electrochemical pathway by carbon anode electrodes in an undivided cell.展开更多
基金Supported by the National Natural Science Foundation of China(No.51278118)the Program for Special Talent in Six Fields of Jiangsu Province(No.2011JZ010)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK2012756)the Undergraduate Innovation Program(No.T13052007)
文摘In order to improve the seismic performance, deformation ability and ultimate load-carrying capacity of columns with rectangular cross section, engineered cementitious composite （ECC） is introduced to partially substitute concrete in the edge zone of reinforced concrete columns and form reinforced ECC/concrete composite columns. Firstly, based on the assumption of plane remaining plane and the simplified constitutive models, the calculation method of the load-carrying capacity of reinforced ECC/concrete columns is proposed. The stress and strain distribu- tions and crack propagation of the composite columns in different states of eccentric compressive loading are ana- lyzed. Then, nonlinear finite element analysis is conducted to study the mechanical performance of reinforced ECC/concrete composite columns with rectangular cross section. It is found that the simulation results are in good agreement with the theoretical results, indicating that the proposed method for calculating the load-carrying capacity of concrete/ECC composite columns is valid. Finally, based on the proposed method, the effects of ECC thickness, com- pressive strength of concrete and longitudinal reinforcement ratio on the mechanical performance of reinforced ECC/ concrete composite columns are analyzed. Calculation results indicate that increasing the thickness of ECC layer or longitudinal reinforcement ratio can effectively increase the ultimate load-carrying capacity of the composite column with both small and large eccentricity, but increasing the strength of concrete can only increase the ultimate Ioad- carrying capacity of the composite column with small eccentricity.
基金Semnan University Research Council,Semnan,Iran for financial supports to this work
文摘Electrochemical oxidation of 4-methyl catechol（1a） is investigated in the presence of 1,3-indandione（3）as nucleophile in phosphate buffer solution（0.2 mol/L,pH 6） mixed with ethanol as organic green solvent（50/50） using cyclic voltammetry and controlled-potential coulometry.The results indicated thatquinones derived from electro-oxidation of 1a,participated in a 1,4-Michael addition reaction with1,3-indandione（3） under ECCE mechanism.In this direction,a new bis-quinone was synthesized in high yield and good purity using a facile and convenient electrochemical pathway by carbon anode electrodes in an undivided cell.
