Benefiting from advances in feature technology for design and manufacture can not be expected before a formal methodology is established. This paper makes attempt to establish a definition formalism of machining featu...Benefiting from advances in feature technology for design and manufacture can not be expected before a formal methodology is established. This paper makes attempt to establish a definition formalism of machining features in design for manufacturability from two aspects: formal definition and manufacturability analysis. Some definitions for machining feature based upon the selection and sequencing of material removal operations for component in accordance with the design geometry are presented and a framework of feature based design for manufacturability is outlined correspondingly. The proposed scheme contributes to several aspects of feature based CAD/CAM integration, especially to encourage potentially a more generic approach to the automation of design.展开更多
A constrained decoupling (generalized predictive control) GPC algorithm is proposed for MIMO (malti-input multi-output) system. This algorithm takes account of all constraints of inputs and their increments. By solvin...A constrained decoupling (generalized predictive control) GPC algorithm is proposed for MIMO (malti-input multi-output) system. This algorithm takes account of all constraints of inputs and their increments. By solving matrix equations, the multi-step predictive decoupling controllers are realized. This algorithm need not solve Diophantine functions, and weakens the cross-coupling of the variables. At last the simulation results demon- strate the effectiveness of this proposed strategy.展开更多
Construction Coercion （CC）, as an important component of Construction Grammar （Cx G） established in 1995 by Goldberg, has aroused much attention of cognitivist and constructionist scholars abroad and at home in th...Construction Coercion （CC）, as an important component of Construction Grammar （Cx G） established in 1995 by Goldberg, has aroused much attention of cognitivist and constructionist scholars abroad and at home in the past two decades. A series of studies have explore its definition, motivation, principle, type, function, explanatory power and etc. As CC is still a quite young field and lots of relevant theoretical studies and experimental studies have been implemented, it is necessary to review previous development of CC which enables us to better understand its current situation and prospect. This paper aims to make a review on CC to give some implications for further studies and finds that studies abroad and at home have some similarities but show different focuses and denote different developmental trends.展开更多
The subject of this research is the policing activities in France during 2004-2005 towards its Muslim population and related public discourses. It will compare the statistics of judiciary police and administrative pol...The subject of this research is the policing activities in France during 2004-2005 towards its Muslim population and related public discourses. It will compare the statistics of judiciary police and administrative police provided by the French authority in order to study the relation between surveillance activities and criminality of the given population. It will point out that the preventative measures taken by the administrative police specifically towards the Muslim population are disproportionately high in comparison to the actual occurences of terrorist actions committed by the group. Using the notion of securitization as an analytical tool, the paper will explain that the cohabitation with the Muslim population had been represented as an existential threat in France justifying severe measures disproportionate to the objective threat. It concludes that the acute vigilance surrounding the Muslims derives significantly from the raised ＂securityness＂ the French authority itself attributed to its Muslim population. The argument presented in this study adds an important perspective to the study of immigration. It shows how an escalation of securitization leads to heightened tension between the immigrants and the host society, actualizing the perceived threat by its own acts.展开更多
Attempts had been made to synthesize Al2O3-2SiO2 nanopowders by sol-gel method with tetraethoxysilane（TEOS） and aluminum nitrate（ANN） as the starting materials.DTS,TEM,SEM and BET were employed to study the effect...Attempts had been made to synthesize Al2O3-2SiO2 nanopowders by sol-gel method with tetraethoxysilane（TEOS） and aluminum nitrate（ANN） as the starting materials.DTS,TEM,SEM and BET were employed to study the effects of process parameters on the size,specific surface area and structure（morphology） of powders.The alkali-activation reactivity of the powders was tested for manufacturing geopolymers and their hydrothermal reactions were performed for fabricating zeolites.The results show that the optimum process parameters and drying method for preparing Al2O3-2SiO2 nanopowders are as follows：the molar ratio of water and ethanol to TEOS are 0：1 and 12：1 respectively at synthetic temperature of 50 ℃ and the drying method is azeotropic distillation with microwave drying.The average particle diameters of the powders were about 70 nm and the largest BET specific surface area was up to 669 m^2·g^-1.The compressive strength of the geopolymer and the calcium exchange capacity（by CaCO3） of NaA zeolite prepared with the powders reached to 29 MPa and 366 m^2·g^-1 respectively.展开更多
文摘Benefiting from advances in feature technology for design and manufacture can not be expected before a formal methodology is established. This paper makes attempt to establish a definition formalism of machining features in design for manufacturability from two aspects: formal definition and manufacturability analysis. Some definitions for machining feature based upon the selection and sequencing of material removal operations for component in accordance with the design geometry are presented and a framework of feature based design for manufacturability is outlined correspondingly. The proposed scheme contributes to several aspects of feature based CAD/CAM integration, especially to encourage potentially a more generic approach to the automation of design.
基金Supported by the National Natural Science Foundation of China (No.60374037, No.60574036), the Program for New Century Excellent Talents in University of China (NCET), and the Specialized Research Fund for the Doctoral Program of Higher Edu-cation of China (No.20050055013).
文摘A constrained decoupling (generalized predictive control) GPC algorithm is proposed for MIMO (malti-input multi-output) system. This algorithm takes account of all constraints of inputs and their increments. By solving matrix equations, the multi-step predictive decoupling controllers are realized. This algorithm need not solve Diophantine functions, and weakens the cross-coupling of the variables. At last the simulation results demon- strate the effectiveness of this proposed strategy.
文摘Construction Coercion （CC）, as an important component of Construction Grammar （Cx G） established in 1995 by Goldberg, has aroused much attention of cognitivist and constructionist scholars abroad and at home in the past two decades. A series of studies have explore its definition, motivation, principle, type, function, explanatory power and etc. As CC is still a quite young field and lots of relevant theoretical studies and experimental studies have been implemented, it is necessary to review previous development of CC which enables us to better understand its current situation and prospect. This paper aims to make a review on CC to give some implications for further studies and finds that studies abroad and at home have some similarities but show different focuses and denote different developmental trends.
文摘The subject of this research is the policing activities in France during 2004-2005 towards its Muslim population and related public discourses. It will compare the statistics of judiciary police and administrative police provided by the French authority in order to study the relation between surveillance activities and criminality of the given population. It will point out that the preventative measures taken by the administrative police specifically towards the Muslim population are disproportionately high in comparison to the actual occurences of terrorist actions committed by the group. Using the notion of securitization as an analytical tool, the paper will explain that the cohabitation with the Muslim population had been represented as an existential threat in France justifying severe measures disproportionate to the objective threat. It concludes that the acute vigilance surrounding the Muslims derives significantly from the raised ＂securityness＂ the French authority itself attributed to its Muslim population. The argument presented in this study adds an important perspective to the study of immigration. It shows how an escalation of securitization leads to heightened tension between the immigrants and the host society, actualizing the perceived threat by its own acts.
基金Supported by the National Natural Science Foundation of China (50962002,50602006)Opening Funds of State Key Laboratory of Chemical Resource Engineering of Beijing University of Chemical Technology (201008)
文摘Attempts had been made to synthesize Al2O3-2SiO2 nanopowders by sol-gel method with tetraethoxysilane（TEOS） and aluminum nitrate（ANN） as the starting materials.DTS,TEM,SEM and BET were employed to study the effects of process parameters on the size,specific surface area and structure（morphology） of powders.The alkali-activation reactivity of the powders was tested for manufacturing geopolymers and their hydrothermal reactions were performed for fabricating zeolites.The results show that the optimum process parameters and drying method for preparing Al2O3-2SiO2 nanopowders are as follows：the molar ratio of water and ethanol to TEOS are 0：1 and 12：1 respectively at synthetic temperature of 50 ℃ and the drying method is azeotropic distillation with microwave drying.The average particle diameters of the powders were about 70 nm and the largest BET specific surface area was up to 669 m^2·g^-1.The compressive strength of the geopolymer and the calcium exchange capacity（by CaCO3） of NaA zeolite prepared with the powders reached to 29 MPa and 366 m^2·g^-1 respectively.
