A reduced mechanism for propane/air combustion and its flame inhibition by phosphorus-containing compounds (PCCs) is constructed with the level of importance (LOI) method. The analysis is performed on solutions of fre...A reduced mechanism for propane/air combustion and its flame inhibition by phosphorus-containing compounds (PCCs) is constructed with the level of importance (LOI) method. The analysis is performed on solutions of freely propagating premixed flames with detailed chemical kinetics involving 121 species and 682 reactions proposed by Jayaweera et al. For the non-homogeneous reaction-diffusion system, the chemical lifetime of each species is weighted by its diffusion timescale, and the characteristic flame timescale is used to normalize the chemical lifetime. The definition of sensitivity in LOI is extended so that multi-parameters can be used as sensitivity targets. Propane, oxygen, dimethyl methylphosphonate (DMMP), and flame speed are selected to be perturbed for sensitivity analysis, the species with low LOI index are removed, and reactions involving the redundant species are excluded from the mechanism. A skeletal mechanism is obtained, which consists of 57 species and 268 elementary reactions. Calculations for laminar flame speeds, key flame radicals and catalytic cycles using the skeletal mechanism are in good agreement with those by using the detailed mechanism over a wide range of equivalence ratio undoped and doped with DMMP.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
基金Supported by the National Natural Science Foundation of China （50876097） the Program for New Century Excellent Talents in University of China （NCET-06-0546）
文摘A reduced mechanism for propane/air combustion and its flame inhibition by phosphorus-containing compounds (PCCs) is constructed with the level of importance (LOI) method. The analysis is performed on solutions of freely propagating premixed flames with detailed chemical kinetics involving 121 species and 682 reactions proposed by Jayaweera et al. For the non-homogeneous reaction-diffusion system, the chemical lifetime of each species is weighted by its diffusion timescale, and the characteristic flame timescale is used to normalize the chemical lifetime. The definition of sensitivity in LOI is extended so that multi-parameters can be used as sensitivity targets. Propane, oxygen, dimethyl methylphosphonate (DMMP), and flame speed are selected to be perturbed for sensitivity analysis, the species with low LOI index are removed, and reactions involving the redundant species are excluded from the mechanism. A skeletal mechanism is obtained, which consists of 57 species and 268 elementary reactions. Calculations for laminar flame speeds, key flame radicals and catalytic cycles using the skeletal mechanism are in good agreement with those by using the detailed mechanism over a wide range of equivalence ratio undoped and doped with DMMP.
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.
