In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatograp...In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatography （IGC） in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption （TPD） technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.展开更多
The chaotic scale-up approach by matching the Kolmogorov entropy(E_K) proposed by Schouten et al.(1996) was assessed in two geometrically similar gas–solid fluidized bed columns of 0.14 and 0.44 m diameter.We used fo...The chaotic scale-up approach by matching the Kolmogorov entropy(E_K) proposed by Schouten et al.(1996) was assessed in two geometrically similar gas–solid fluidized bed columns of 0.14 and 0.44 m diameter.We used four conditions of our validated new mechanistic scale-up method based on matching the radial profiles of gas holdup where the local dimensionless hydrodynamic parameters were similar as measured by advanced measurement techniques.These experimental conditions were used to evaluate the validity of the chaotic scale-up method,which were selected based on our new mechanistic scale-up methodology.Pressure gauge transducer measurements at the wall and inside the bed at various local radial locations and at three axial heights were used to estimate KE.It was found that the experimental conditions with similar or close radial profiles of the Kolmogorov entropy and with similar or close radial profiles of the gas holdup achieve the similarity in local dimensionless hydrodynamic parameters,and vice versa.展开更多
Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsi...Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined. In the experiments, in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe203 to Fe3O4, the reaction temperatures were set between 440 ℃ and 490 ℃. However, in order to distinguish the reduction of Fe304 to FeO from that of FeO to Fe, the reaction temperature in the experiment was set to be greater than 570 ℃. Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.展开更多
Interaction of Aristolochic acid （AA） and guanine （G） was studied by electrochemical techniques in this paper. When AA was added into the guanine solution, the oxidation peak currents of mixture solution decreased...Interaction of Aristolochic acid （AA） and guanine （G） was studied by electrochemical techniques in this paper. When AA was added into the guanine solution, the oxidation peak currents of mixture solution decreased, while the peak potential and the electrochemical kinetic parameters remained the same as when AA was absent, except that the electrode process of guanine that involved two protons and two electrons changed from adsorption controlled to diffusion controlled. It is suggested that an electrochemical inactive supramolecular adduct AA-Gua （1：1） was formed in the system. The adduct cannot be oxidized on the glassy carbon electrode, which indirectly results in the decrease of the free concentration of guanine in the reaction solution and the decrease of peak currents. The binding constant （13） of this adduct is calculated as 7.14× 10^3 mol/L. The possible mechanism for the interaction of Aristolochic acid and DNA was proposed, that may provide a possible pathway for the nosogenesis research of aristolochic acid.展开更多
Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various tempera...Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various temperatures.Electrochemical reaction kinetic parameters were also studied with proper electrochemical techniques.The influence of the secondary corrosion reaction on the anodic linear polarization measurement was also analyzed by theoretical simulation.The results show that,proper ball-milling with nickel powders is beneficial to electrochemical performance.The theoretical simulation proves that,the existence of the side reaction can disturb the measurement of electrochemical reaction kinetic parameters.展开更多
文摘In this work, the thermodynamic parameters for the adsorption of water vapor on untreated silica gel and silica gel treated with hygroscopic salts and silane coupling agent were determined by lnverse Gas Chromatography （IGC） in the infinite dilution region. The desorption activation energies of the water vapor on virgin and modified silica gels were estimated by using the Temperature Programmed Desorption （TPD） technique. The interactions between the water and the virgin and modified silica gels were discussed. Results showed that the thermodynamic parameters and desorption activation energy of water vapour on the silica gels increase with decreasing pore size and increasing the surface hydrophilic properties. The desorption activation energy of virgin and modified silica gels was found to increase with increasing the thermodynamic parameters. The larger the adsorption parameters and the desorption activation energy were, the interactions between water and virgin and modified silica gels were.
基金the Multiphase Reactors Engineering and Applications Laboratory(mReal) for funding and support
文摘The chaotic scale-up approach by matching the Kolmogorov entropy(E_K) proposed by Schouten et al.(1996) was assessed in two geometrically similar gas–solid fluidized bed columns of 0.14 and 0.44 m diameter.We used four conditions of our validated new mechanistic scale-up method based on matching the radial profiles of gas holdup where the local dimensionless hydrodynamic parameters were similar as measured by advanced measurement techniques.These experimental conditions were used to evaluate the validity of the chaotic scale-up method,which were selected based on our new mechanistic scale-up methodology.Pressure gauge transducer measurements at the wall and inside the bed at various local radial locations and at three axial heights were used to estimate KE.It was found that the experimental conditions with similar or close radial profiles of the Kolmogorov entropy and with similar or close radial profiles of the gas holdup achieve the similarity in local dimensionless hydrodynamic parameters,and vice versa.
基金Supported by the National Natural Science Foundation of China (20736004)the State Key Development Program for Basic Research of China (2007CB613502)
文摘Kinetics parameters of iron oxide reduction by hydrogen were evaluated by the isothermal method in a differential micro-packed bed. Influence of external diffusion, internal diffusion and heat transfer on the intrinsic reaction rate was investigated and the conditions free of internal and external diffusion resistance have been determined. In the experiments, in order to correctly evaluate the intrinsic kinetics parameters for reducing Fe203 to Fe3O4, the reaction temperatures were set between 440 ℃ and 490 ℃. However, in order to distinguish the reduction of Fe304 to FeO from that of FeO to Fe, the reaction temperature in the experiment was set to be greater than 570 ℃. Intrinsic kinetics of iron oxide reduction by hydrogen was established and the newly established kinetic models were validated by the experimental data.
基金Acknowledgements： Financial support from the National Natural Science Foundation of China （No. 20305004）, Program for New Century Excellent Talents in University （No, NCET-05-0572） of China, the Key Science and Technology project of Fujian Province （No. 2005Y015） and the National Natural Science Foundation of Fujian Province （No. D0510006）.
文摘Interaction of Aristolochic acid （AA） and guanine （G） was studied by electrochemical techniques in this paper. When AA was added into the guanine solution, the oxidation peak currents of mixture solution decreased, while the peak potential and the electrochemical kinetic parameters remained the same as when AA was absent, except that the electrode process of guanine that involved two protons and two electrons changed from adsorption controlled to diffusion controlled. It is suggested that an electrochemical inactive supramolecular adduct AA-Gua （1：1） was formed in the system. The adduct cannot be oxidized on the glassy carbon electrode, which indirectly results in the decrease of the free concentration of guanine in the reaction solution and the decrease of peak currents. The binding constant （13） of this adduct is calculated as 7.14× 10^3 mol/L. The possible mechanism for the interaction of Aristolochic acid and DNA was proposed, that may provide a possible pathway for the nosogenesis research of aristolochic acid.
文摘Ti0.5Al0.25Ni0.25 alloy prepared by vacuum induction melting was studied.The phase composition was analyzed with X-ray technique and EDS analysis,and its electrochemical properties were investigated at various temperatures.Electrochemical reaction kinetic parameters were also studied with proper electrochemical techniques.The influence of the secondary corrosion reaction on the anodic linear polarization measurement was also analyzed by theoretical simulation.The results show that,proper ball-milling with nickel powders is beneficial to electrochemical performance.The theoretical simulation proves that,the existence of the side reaction can disturb the measurement of electrochemical reaction kinetic parameters.
