Based on the nearest surface function formula, a quantitative formula to measure the overlapping degree between the interfacial transition zone （ITZ） of neighboring aggregate particles was put forward. The formula w...Based on the nearest surface function formula, a quantitative formula to measure the overlapping degree between the interfacial transition zone （ITZ） of neighboring aggregate particles was put forward. The formula was further deduced to quantitatively analyze the influence of the volume fraction of aggregate, ITZ thickness and the maximum aggregate diameter on the overlapping degree between neighboring ITZ. The volume of ITZ was quantitatively calculated in actual concrete by comparing the nearest surface function formula with an approximate method, that is the surface area of the aggregates multiplied by the uniform thickness of the ITZ layers. The results showed that the influencing order of these three factors on the overlapping degree between neighboring ITZ in turn was the interface thickness, aggregate volume fraction and the maximum aggregate diameter; As long as the interface thickness 50 μm and the aggregate volume fraction 50%, the calculated error between two methods mentioned above is about 10 %.展开更多
To solve the problems existing in the flow characteristics of steam turbine unit, the influence of valve overlap degree on nozzle governing steam turbine had been studied. The combined flow characteristics of given va...To solve the problems existing in the flow characteristics of steam turbine unit, the influence of valve overlap degree on nozzle governing steam turbine had been studied. The combined flow characteristics of given valve overlap degree were obtained for a 600MW steam turbine unit by the method of theoretical calculation combined with simulation test, and the influence of valve overlap degree on governing stage efficiency and steam chest pressure had been also analyzed. This paper discussed the selection of rational overlap degree and introduced a new method of building model for governing stage efficiency of steam turbine in constant pressure operation condition, which provided theoretical guidance for optimization research on nozzle governing steam turbine operation.展开更多
Based on the expression of the index of coil interpenetration （i.e., the degree of coil overlap, ξb） of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory...Based on the expression of the index of coil interpenetration （i.e., the degree of coil overlap, ξb） of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory＇s intrinsic viscosity equation at them conditions. The ξb ofpoly （vinyl chloride） （PVC） dense membranes with different molecular weights and cellulose diacetate （CA） dense membranes prepared using different solvents were determined. The permeability, permeation coefficient （P） of nitrogen and permeation flux （J） of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed.展开更多
The “overlapping equilibria” effect observed in the processes of electrolytic dissociation of many weak multibasic organic acids determines the character of these processes. In this communication, the degree of “ov...The “overlapping equilibria” effect observed in the processes of electrolytic dissociation of many weak multibasic organic acids determines the character of these processes. In this communication, the degree of “overlapping equilibria” in case of weak dibasic organic acids is quantitatively characterized by the values of “partial” degree of dissociation for second step and ratio of the concentrations of dianion and monoanion. It has been shown that these dissociation parameters are directly connected with the values of the second dissociation constant. It has been also shown that the contribution of third dissociation step in the “overlapping equilibria” effect is especially appreciable in case of penta and hexabasic weak organic acids causing the double “overlapping” phenomenon.展开更多
An improvement of tolerance relation is proposed in regard to rough set model based on connection degree by which reflexivity of relation can be assured without loss of information. Then, a method to determine optimal...An improvement of tolerance relation is proposed in regard to rough set model based on connection degree by which reflexivity of relation can be assured without loss of information. Then, a method to determine optimal identity degree based on relative positive region is proposed so that the identity degree can be computed in an objective method without any preliminary or additional information about data, which is consistent with the notion of objectivity in rough set theory and data mining theory. Subsequently, an algorithm is proposed, and in two examples, the global optimum identity degree is found out. Finally, in regard to optimum connection degree, the method of rules extraction for connection degree rough set model based on generalization function is presented by which the rules extracted from a decision table are enumerated.展开更多
Teacher identity has emerged as a central topic in educational research since 1990s. Professional identity among university EFL teachers is however understudied, especially those were engaged in in-service PhD study. ...Teacher identity has emerged as a central topic in educational research since 1990s. Professional identity among university EFL teachers is however understudied, especially those were engaged in in-service PhD study. Drawing on the interviews with nine EFL teachers in a Chinese university, this qualitative case research explored the changes of their professional identity with in-service PhD study experience. Positive changes were reported by all nine teachers, although with varied loci. Consistent with prior studies, the nine teachers demonstrated multi-leveled, achievement-oriented and discipline-focused professional identities. This research highlights the powerful influence of policy upon their identity changes. Their professional identities are shaped and reshaped in the process of negotiating and balancing between personal beliefs and rules at different levels. Teachers with non-English PhD academic background displayed conflicting professional identity, with institutional pressure being the important sources of their struggle and dilemma.展开更多
基金Funded by the National Basic Research Program of China (No.2009CB623203)National High-tech R&D Program of China (No.2008AA030794)Postgraduates Research Innovation in University of Jiangsu Province in China (No.CX10B-064Z)
文摘Based on the nearest surface function formula, a quantitative formula to measure the overlapping degree between the interfacial transition zone （ITZ） of neighboring aggregate particles was put forward. The formula was further deduced to quantitatively analyze the influence of the volume fraction of aggregate, ITZ thickness and the maximum aggregate diameter on the overlapping degree between neighboring ITZ. The volume of ITZ was quantitatively calculated in actual concrete by comparing the nearest surface function formula with an approximate method, that is the surface area of the aggregates multiplied by the uniform thickness of the ITZ layers. The results showed that the influencing order of these three factors on the overlapping degree between neighboring ITZ in turn was the interface thickness, aggregate volume fraction and the maximum aggregate diameter; As long as the interface thickness 50 μm and the aggregate volume fraction 50%, the calculated error between two methods mentioned above is about 10 %.
文摘To solve the problems existing in the flow characteristics of steam turbine unit, the influence of valve overlap degree on nozzle governing steam turbine had been studied. The combined flow characteristics of given valve overlap degree were obtained for a 600MW steam turbine unit by the method of theoretical calculation combined with simulation test, and the influence of valve overlap degree on governing stage efficiency and steam chest pressure had been also analyzed. This paper discussed the selection of rational overlap degree and introduced a new method of building model for governing stage efficiency of steam turbine in constant pressure operation condition, which provided theoretical guidance for optimization research on nozzle governing steam turbine operation.
文摘Based on the expression of the index of coil interpenetration （i.e., the degree of coil overlap, ξb） of amorphous polymers in the bulk state proposed by Qian, the ξb was rewritten as ξb = ρb [η]θ/1.66 via Hory＇s intrinsic viscosity equation at them conditions. The ξb ofpoly （vinyl chloride） （PVC） dense membranes with different molecular weights and cellulose diacetate （CA） dense membranes prepared using different solvents were determined. The permeability, permeation coefficient （P） of nitrogen and permeation flux （J） of liquid through both membranes, respectively, was measured. P and J decreased exponentially with increasing ξb for PVC and CA membranes were revealed.
文摘The “overlapping equilibria” effect observed in the processes of electrolytic dissociation of many weak multibasic organic acids determines the character of these processes. In this communication, the degree of “overlapping equilibria” in case of weak dibasic organic acids is quantitatively characterized by the values of “partial” degree of dissociation for second step and ratio of the concentrations of dianion and monoanion. It has been shown that these dissociation parameters are directly connected with the values of the second dissociation constant. It has been also shown that the contribution of third dissociation step in the “overlapping equilibria” effect is especially appreciable in case of penta and hexabasic weak organic acids causing the double “overlapping” phenomenon.
基金supported by the National Natural Science Foundation of China (70571032)
文摘An improvement of tolerance relation is proposed in regard to rough set model based on connection degree by which reflexivity of relation can be assured without loss of information. Then, a method to determine optimal identity degree based on relative positive region is proposed so that the identity degree can be computed in an objective method without any preliminary or additional information about data, which is consistent with the notion of objectivity in rough set theory and data mining theory. Subsequently, an algorithm is proposed, and in two examples, the global optimum identity degree is found out. Finally, in regard to optimum connection degree, the method of rules extraction for connection degree rough set model based on generalization function is presented by which the rules extracted from a decision table are enumerated.
文摘Teacher identity has emerged as a central topic in educational research since 1990s. Professional identity among university EFL teachers is however understudied, especially those were engaged in in-service PhD study. Drawing on the interviews with nine EFL teachers in a Chinese university, this qualitative case research explored the changes of their professional identity with in-service PhD study experience. Positive changes were reported by all nine teachers, although with varied loci. Consistent with prior studies, the nine teachers demonstrated multi-leveled, achievement-oriented and discipline-focused professional identities. This research highlights the powerful influence of policy upon their identity changes. Their professional identities are shaped and reshaped in the process of negotiating and balancing between personal beliefs and rules at different levels. Teachers with non-English PhD academic background displayed conflicting professional identity, with institutional pressure being the important sources of their struggle and dilemma.
