According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe...According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe0.5Zr0.1O3-δ oxide-based membranes were systematically compared in terms of oxygen permeability and chemical stability,and their differences were elucidated by means of the theoretical calculation.For the oxygen permeability,the asymmetric membrane was greater than the symmetric membrane due to the significant decrease of bulk diffusion resistance in the thin dense layer of the asymmetric membrane.In regard to the chemical stability,the increase of oxygen partial pressure on the asymmetric membrane surface at CH4 side produced the stable time of over 1032h in partial oxidation of methane at 1123K,while the symmetric membrane was only of 528h.This study demonstrated that the asymmetric membrane was a promising geometrical configuration for the practical application.展开更多
The authors consider the homogenization of a class of nonlinear variational inequalities,which include rapid oscillations with respect to a parameter.The homogenization of the corresponding class of differential equat...The authors consider the homogenization of a class of nonlinear variational inequalities,which include rapid oscillations with respect to a parameter.The homogenization of the corresponding class of differential equations is also studied.The results are applied to some models for the pressure in a thin fluid film fluid between two surfaces which are in relative motion.This is an important problem in the lubrication theory.In particular,the analysis includes the effects of surface roughness on both faces and the phenomenon of cavitation.Moreover,the fluid can be modeled as Newtonian or non-Newtonian by using a Rabinowitsch fluid model.展开更多
基金Supported by the National Basic Research Program of China （2009CB623406）, the National Natural Science Foundation of China （20636020）, the National High Technology Research and Development Program of China （2006AA030204） and the Specialized Research Fund for the Doctoral Program of Higher Education of China （20060291003）.
文摘According to the configuration,mixed-conducting membranes are classified as symmetric membranes and asymmetric membranes consisting of a thin dense layer and a porous support.In this study,these two kinds of SrCo0.4Fe0.5Zr0.1O3-δ oxide-based membranes were systematically compared in terms of oxygen permeability and chemical stability,and their differences were elucidated by means of the theoretical calculation.For the oxygen permeability,the asymmetric membrane was greater than the symmetric membrane due to the significant decrease of bulk diffusion resistance in the thin dense layer of the asymmetric membrane.In regard to the chemical stability,the increase of oxygen partial pressure on the asymmetric membrane surface at CH4 side produced the stable time of over 1032h in partial oxidation of methane at 1123K,while the symmetric membrane was only of 528h.This study demonstrated that the asymmetric membrane was a promising geometrical configuration for the practical application.
文摘The authors consider the homogenization of a class of nonlinear variational inequalities,which include rapid oscillations with respect to a parameter.The homogenization of the corresponding class of differential equations is also studied.The results are applied to some models for the pressure in a thin fluid film fluid between two surfaces which are in relative motion.This is an important problem in the lubrication theory.In particular,the analysis includes the effects of surface roughness on both faces and the phenomenon of cavitation.Moreover,the fluid can be modeled as Newtonian or non-Newtonian by using a Rabinowitsch fluid model.
