The deflection angle of a river bend plays an important role on behaviours of the flow within it, and a clear understanding of the angle's influence is significant in both theoretical study and engineering applica...The deflection angle of a river bend plays an important role on behaviours of the flow within it, and a clear understanding of the angle's influence is significant in both theoretical study and engineering application. This paper presents a systematic numerical investigation on effects of deflection angles(30°, 60°, 90°, 120°, 150°, and 180°) on flow phenomena and their evolution in open-channel bends using a Re-Normalization Group(RNG) κ-ε model and a volume of fluid(VOF) method. The numerical results indicate that the deflection angle is a key factor for flows in bends. It is shown that the maximum transverse slope of water surface occurs at the middle cross section of a bend, and it increases with the deflection angle. Besides a major vortex, or, the primary circulation cell near the channel bottom, a secondary vortex, or, an outer bank cell, may also appear above the former and near the outer bank when the deflection angle is sufficiently large, and it will gradually migrate towards the inner bank and evolve into an inner bank cell. The strength of the secondary circulations increases with the deflection angle. The simulation demonstrates that there is alow-stress zone on the bed near the outer bank and a high-stress zone on the bed near the inner bank, and both of them increase in size with the deflection angle. The maximum of shear stress on the inner bank increases nonlinearly with the angle, and its maximums on the outer bank and on the bed take place when the deflection angle becomes 120°.展开更多
Teaching theories provide important guidance for language teaching materials development,but there is little research on how textbook writers apply teaching theories in the actual writing process.This study analyzes t...Teaching theories provide important guidance for language teaching materials development,but there is little research on how textbook writers apply teaching theories in the actual writing process.This study analyzes the process of compiling iEnglish,a series of textbooks based on the Production-Oriented Approach(POA)and proposes an Integrated Model of Teaching Theory and Action Research for textbook writing.By elaborating the roles of teaching theory and action research at different stages of textbook writing and the interaction between theory and practice during the process,the study concludes that the Integrated Model can promote both textbook improvement and theory refinement.展开更多
Due to low carrying capacity and short life of current ring reducer,we proposed a new planetary gearing with internal gear ring,which consisted of two stages.One was an involute planetary drive and the other was an N-...Due to low carrying capacity and short life of current ring reducer,we proposed a new planetary gearing with internal gear ring,which consisted of two stages.One was an involute planetary drive and the other was an N-type planetary drive with small teeth difference.The kinematic calculation was conducted based on the analysis of structural composition and working principle.Formulas of backlash calculation for the new planetary gearing were derived by using probabilistic theory and the analytical model was created at the same time.Then,main factors that affect the systematic backlash were introduced and the effects of manufacture error,misaligments and roller bearing parameters on the distribution of backlash were presented.The influence of gear backlash on systematic return difference was performed based on the backlash mathematic model proposed.The results show that the backlash is a little large,of which the backlash of bearing takes a greater part than two gearing stages.So we presented some practical methods to reduce the systematic backlash.展开更多
Nowadays,there are many studies conducted in the field of marine hydrodynamics which focus on two vessels traveling and floating in sufficiently close proximity to experience significant interactions.The hydrodynamic ...Nowadays,there are many studies conducted in the field of marine hydrodynamics which focus on two vessels traveling and floating in sufficiently close proximity to experience significant interactions.The hydrodynamic behavior of parallel moving ships in waves is an interesting and important topic of late.A numerical investigation has been carried out for the prediction of wave exciting forces and motion responses of parallel moving ships in regular waves.The numerical solution was based on 3D distribution technique and using the linear wave theory to determine the exciting forces and ship＇s motion.The speed effects have been considered in the Green function for more realistic results.The numerical computations of wave exciting forces and motion responses were carried out for a Mariner and Series 60 for the purpose of discovering different Froude numbers and different separation distances in head sea conditions.Based on the numerical computations,it was revealed that the sway,roll and yaw have a significant effect due to hydrodynamic interaction.展开更多
A competition model of three species in exchange-driven aggregation growth is proposed. In the model, three distinct aggregates grow by exchange of monomers and in parallel, birth of species A is catalyzed by species ...A competition model of three species in exchange-driven aggregation growth is proposed. In the model, three distinct aggregates grow by exchange of monomers and in parallel, birth of species A is catalyzed by species B and death of species A is catalyzed by species C. The rates for both catalysis processes are proportional to kj^v and ky respectively, where ν（ω） is a parameter reflecting the dependence of the catalysis reaction rate of birth （death） on the catalyst aggregate＇s size. The kinetic evolution behaviors of the three species are investigated by the rate equation approach based on the mean-field theory： The form of the aggregate size distribution of A-species αk（t） is found to be dependent crucially on the two catalysis rate kernel parameters. The results show that （i） in case of ν ≤O, the form of ak （t） mainly depends on the competition between self-exchange of species A and species-C-catalyzed death of species A; （ii） in case of ν 〉 0, the form of αk（t） mainly depends on the competition between species-B-catalyzed birth of species A and species-C-catalyzed death of species A.展开更多
This research seeks to contribute to translation studies by examining the illocutionary force of the speech act theory. It identifies two senses of illocutionary force： The active function of language is defined as l...This research seeks to contribute to translation studies by examining the illocutionary force of the speech act theory. It identifies two senses of illocutionary force： The active function of language is defined as lFl and the varying degrees of the strength of the speech act are defined as IF2. The implications of the two senses ofillocutionary force for translation studies are discussed in a case study of the translation of directives in Chinese versions of Shakespeare＇s play, The Merry Wives of Windsor. Translation shifts in transferring IF2, as manifested in pragmatic duality features of directness/indirectness, tone articles, repetition of verbs, action measure verbs, upgrader ＂,给我＂ and honorific addressing terms and vocatives are discussed. The notion＇s potential as a criterion to evaluate translation quality is also explored.展开更多
In order to minimize the harm caused by the instability of a planing craft, a motion prediction model is essential. This paper analyzed the feasibility of using an MGM（1,N） model in grey system theory to predict pla...In order to minimize the harm caused by the instability of a planing craft, a motion prediction model is essential. This paper analyzed the feasibility of using an MGM（1,N） model in grey system theory to predict planing craft motion and carried out the numerical simulation experiment. According to the characteristics of planing craft motion, a recurrence formula was proposed of the parameter matrix of an MGMfl,N） model. Using this formula, data can be updated in real-time without increasing computational complexity significantly. The results of numerical simulation show that using an MGM（1,N） model to predict planing motion is feasible and useful for prediction. So the method proposed in this study can reflect the planing craft motion mechanism successfully, and has rational and effective functions of forecasting and analyzing trends.展开更多
The system uses B / S mode and ASP as the web-based support and connects with the SQL Server 2005 database, which realizes the automatic and manual assessment of Photoshop course exam management operations. At the sam...The system uses B / S mode and ASP as the web-based support and connects with the SQL Server 2005 database, which realizes the automatic and manual assessment of Photoshop course exam management operations. At the same time, it will be able to generate paper reference to test the difficulty levels of papers.展开更多
To eliminate the perturbation of interceptor detection induced by aerodynamic heating,the head pursuit (HP) guidance law for three-dimensional interception was presented. The guidance law positioned the interceptor ah...To eliminate the perturbation of interceptor detection induced by aerodynamic heating,the head pursuit (HP) guidance law for three-dimensional interception was presented. The guidance law positioned the interceptor ahead of the target on its flight trajectory,and the speed of interceptor was required to be lower than that of the target. On the basis of a novel head pursuit three-dimensional guidance model,a nonlinear guidance law was developed based on smooth sliding mode control theory. At the same time,a special observer was designed to estimate the target acceleration,and a numerical example on maneuvering ballistic target interception verified the effectiveness of the presented guidance law.展开更多
Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled ene...Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled energies below ionization threshold. The results show that with the increase of the scaled energy, the number of the closed orbit increases greatly. Some of the orbits are created by the bifurcation of the perpendicular orbit. This case is quite similar to the Rydberg atom in an electric field. When the scaled energy increases furthermore, chaotic orbits appear. This study provides a different perspective on the dynamical behavior of the Rydberg atom near a metal surface.展开更多
Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level ...Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level and the mechanism level of conceptual design.The principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters.Then on the basis of mentioned above,the heuristic matching propagation principle (HMPP) of kinematic behaviors and its true table serves as a guide to perform mechanism types selection.Finally an application is given to indicate its practicability and effectiveness.展开更多
Despite the expansion of Chinese education and the steady rise in the educational level of urban and rural residents since reform and opening up, the problem of educational inequality has persisted. This study employs...Despite the expansion of Chinese education and the steady rise in the educational level of urban and rural residents since reform and opening up, the problem of educational inequality has persisted. This study employs CGSS2008 data to test the effects of household registration, family socio-economic status, years of parental education, and sibship size on educational opportunity at the three stages of junior middle school, senior middle school and higher education, as well as the changes in these effects over the period 1978-2008. The results show that there is no observable rural-urban disparity in opportunities for continuation to the junior middle school stage, but there is rising inequality in opporUmities for continuation to senior middle school and higher education; the influence of father＇s occupational status on children＇s educational opportunities remains largely the same, indicating that the stratification of educational attainment has not changed markedly since 1978： years of varental education play a marked and increasing role in children＇s educational attainment; and educational inequality due to sibship size also displays a rising tendency. To understand the structure and evolution of inequality in Chinese education since reform and opening up, it is necessary to study the micro-level mechanisms affecting residents＇ educational decision-making.展开更多
In the past twenty years,great achievements have been made by many researchers in the studies of chaotic behavior and local entropy theory of dynamical systems.Most of the results have been generalized to the relative...In the past twenty years,great achievements have been made by many researchers in the studies of chaotic behavior and local entropy theory of dynamical systems.Most of the results have been generalized to the relative case in the sense of a given factor map.In this survey we offer an overview of these developments.展开更多
基金supported by the National Natural Science Foundation of China(Grant No:51579162,51879174 and 51379137)the Open Funds of the State Key Laboratory of Hydraulics and Mountain River Engineering,Sichuan University(SKHL1301,SKHL1509)
文摘The deflection angle of a river bend plays an important role on behaviours of the flow within it, and a clear understanding of the angle's influence is significant in both theoretical study and engineering application. This paper presents a systematic numerical investigation on effects of deflection angles(30°, 60°, 90°, 120°, 150°, and 180°) on flow phenomena and their evolution in open-channel bends using a Re-Normalization Group(RNG) κ-ε model and a volume of fluid(VOF) method. The numerical results indicate that the deflection angle is a key factor for flows in bends. It is shown that the maximum transverse slope of water surface occurs at the middle cross section of a bend, and it increases with the deflection angle. Besides a major vortex, or, the primary circulation cell near the channel bottom, a secondary vortex, or, an outer bank cell, may also appear above the former and near the outer bank when the deflection angle is sufficiently large, and it will gradually migrate towards the inner bank and evolve into an inner bank cell. The strength of the secondary circulations increases with the deflection angle. The simulation demonstrates that there is alow-stress zone on the bed near the outer bank and a high-stress zone on the bed near the inner bank, and both of them increase in size with the deflection angle. The maximum of shear stress on the inner bank increases nonlinearly with the angle, and its maximums on the outer bank and on the bed take place when the deflection angle becomes 120°.
文摘Teaching theories provide important guidance for language teaching materials development,but there is little research on how textbook writers apply teaching theories in the actual writing process.This study analyzes the process of compiling iEnglish,a series of textbooks based on the Production-Oriented Approach(POA)and proposes an Integrated Model of Teaching Theory and Action Research for textbook writing.By elaborating the roles of teaching theory and action research at different stages of textbook writing and the interaction between theory and practice during the process,the study concludes that the Integrated Model can promote both textbook improvement and theory refinement.
基金Funded by Key Technology R&D Program of Chongqing(No. 2008AC3087)Science & Technology Project of Chongqing Education Committee(No. KJ091414)
文摘Due to low carrying capacity and short life of current ring reducer,we proposed a new planetary gearing with internal gear ring,which consisted of two stages.One was an involute planetary drive and the other was an N-type planetary drive with small teeth difference.The kinematic calculation was conducted based on the analysis of structural composition and working principle.Formulas of backlash calculation for the new planetary gearing were derived by using probabilistic theory and the analytical model was created at the same time.Then,main factors that affect the systematic backlash were introduced and the effects of manufacture error,misaligments and roller bearing parameters on the distribution of backlash were presented.The influence of gear backlash on systematic return difference was performed based on the backlash mathematic model proposed.The results show that the backlash is a little large,of which the backlash of bearing takes a greater part than two gearing stages.So we presented some practical methods to reduce the systematic backlash.
基金support of JASSO to conduct this research work during the author’s stay at Japan
文摘Nowadays,there are many studies conducted in the field of marine hydrodynamics which focus on two vessels traveling and floating in sufficiently close proximity to experience significant interactions.The hydrodynamic behavior of parallel moving ships in waves is an interesting and important topic of late.A numerical investigation has been carried out for the prediction of wave exciting forces and motion responses of parallel moving ships in regular waves.The numerical solution was based on 3D distribution technique and using the linear wave theory to determine the exciting forces and ship＇s motion.The speed effects have been considered in the Green function for more realistic results.The numerical computations of wave exciting forces and motion responses were carried out for a Mariner and Series 60 for the purpose of discovering different Froude numbers and different separation distances in head sea conditions.Based on the numerical computations,it was revealed that the sway,roll and yaw have a significant effect due to hydrodynamic interaction.
基金Supported by the National Natural Science Foundation of China under Grant Nos.10275048,10305009,and 10875086by the Zhejiang Provincial Natural Science Foundation of China under Grant No.102067
文摘A competition model of three species in exchange-driven aggregation growth is proposed. In the model, three distinct aggregates grow by exchange of monomers and in parallel, birth of species A is catalyzed by species B and death of species A is catalyzed by species C. The rates for both catalysis processes are proportional to kj^v and ky respectively, where ν（ω） is a parameter reflecting the dependence of the catalysis reaction rate of birth （death） on the catalyst aggregate＇s size. The kinetic evolution behaviors of the three species are investigated by the rate equation approach based on the mean-field theory： The form of the aggregate size distribution of A-species αk（t） is found to be dependent crucially on the two catalysis rate kernel parameters. The results show that （i） in case of ν ≤O, the form of ak （t） mainly depends on the competition between self-exchange of species A and species-C-catalyzed death of species A; （ii） in case of ν 〉 0, the form of αk（t） mainly depends on the competition between species-B-catalyzed birth of species A and species-C-catalyzed death of species A.
文摘This research seeks to contribute to translation studies by examining the illocutionary force of the speech act theory. It identifies two senses of illocutionary force： The active function of language is defined as lFl and the varying degrees of the strength of the speech act are defined as IF2. The implications of the two senses ofillocutionary force for translation studies are discussed in a case study of the translation of directives in Chinese versions of Shakespeare＇s play, The Merry Wives of Windsor. Translation shifts in transferring IF2, as manifested in pragmatic duality features of directness/indirectness, tone articles, repetition of verbs, action measure verbs, upgrader ＂,给我＂ and honorific addressing terms and vocatives are discussed. The notion＇s potential as a criterion to evaluate translation quality is also explored.
基金Supported by the Foundation of State Key Laboratory of Autonomous Underwater Vehicle, Harbin Engineering Universitythe Fundamental Research Funds for the Central Universities (HEUCFL20101113)
文摘In order to minimize the harm caused by the instability of a planing craft, a motion prediction model is essential. This paper analyzed the feasibility of using an MGM（1,N） model in grey system theory to predict planing craft motion and carried out the numerical simulation experiment. According to the characteristics of planing craft motion, a recurrence formula was proposed of the parameter matrix of an MGMfl,N） model. Using this formula, data can be updated in real-time without increasing computational complexity significantly. The results of numerical simulation show that using an MGM（1,N） model to predict planing motion is feasible and useful for prediction. So the method proposed in this study can reflect the planing craft motion mechanism successfully, and has rational and effective functions of forecasting and analyzing trends.
文摘The system uses B / S mode and ASP as the web-based support and connects with the SQL Server 2005 database, which realizes the automatic and manual assessment of Photoshop course exam management operations. At the same time, it will be able to generate paper reference to test the difficulty levels of papers.
文摘To eliminate the perturbation of interceptor detection induced by aerodynamic heating,the head pursuit (HP) guidance law for three-dimensional interception was presented. The guidance law positioned the interceptor ahead of the target on its flight trajectory,and the speed of interceptor was required to be lower than that of the target. On the basis of a novel head pursuit three-dimensional guidance model,a nonlinear guidance law was developed based on smooth sliding mode control theory. At the same time,a special observer was designed to estimate the target acceleration,and a numerical example on maneuvering ballistic target interception verified the effectiveness of the presented guidance law.
基金supported by National Natural Science Foundation of China under Grant No.10604045the Doctoral Scientific Research Startup Foundation of Ludong University under Grant No.202-23000301
文摘Using closed orbit theory, we give a clear physical picture description of the Rydberg hydrogen atom near a metal surface and calculate the Fourier transformed recurrence spectra of this system at different scaled energies below ionization threshold. The results show that with the increase of the scaled energy, the number of the closed orbit increases greatly. Some of the orbits are created by the bifurcation of the perpendicular orbit. This case is quite similar to the Rydberg atom in an electric field. When the scaled energy increases furthermore, chaotic orbits appear. This study provides a different perspective on the dynamical behavior of the Rydberg atom near a metal surface.
基金Sponsored by the Chinese National Foundation of Science Na 59875058.
文摘Firstly data standardization technology and combined classification method have been applied to carry out classification of kinematic behaviors and mechanisms in the mapping field between the kinematic behavior level and the mechanism level of conceptual design.The principle of computer coding and storing have been built to give a fast and broad selection of mechanisms that meets the requirements of basic motion characters.Then on the basis of mentioned above,the heuristic matching propagation principle (HMPP) of kinematic behaviors and its true table serves as a guide to perform mechanism types selection.Finally an application is given to indicate its practicability and effectiveness.
基金is the outcome of "A Study of the Impact of Modern Education on Social Stratification and Mobility"(CFA090096),a topic for young scholars of education under the 11th Five-year Plan of the National Social Science Fund,with support from both the "Program for Supporting Outstanding Talent of the New Century"(2011) of the Ministry of Education and "Research on Educational Equality in China,"a major Shandong University project in the humanities and social sciences
文摘Despite the expansion of Chinese education and the steady rise in the educational level of urban and rural residents since reform and opening up, the problem of educational inequality has persisted. This study employs CGSS2008 data to test the effects of household registration, family socio-economic status, years of parental education, and sibship size on educational opportunity at the three stages of junior middle school, senior middle school and higher education, as well as the changes in these effects over the period 1978-2008. The results show that there is no observable rural-urban disparity in opportunities for continuation to the junior middle school stage, but there is rising inequality in opporUmities for continuation to senior middle school and higher education; the influence of father＇s occupational status on children＇s educational opportunities remains largely the same, indicating that the stratification of educational attainment has not changed markedly since 1978： years of varental education play a marked and increasing role in children＇s educational attainment; and educational inequality due to sibship size also displays a rising tendency. To understand the structure and evolution of inequality in Chinese education since reform and opening up, it is necessary to study the micro-level mechanisms affecting residents＇ educational decision-making.
基金supported by Foundation for the Authors of National Excellent Doctoral Dissertation of China (Grant No.201018)National Natural Science Foundation of China (Grant No. 10801035)Ministry of Education of China (Grant No. 200802461004)
文摘In the past twenty years,great achievements have been made by many researchers in the studies of chaotic behavior and local entropy theory of dynamical systems.Most of the results have been generalized to the relative case in the sense of a given factor map.In this survey we offer an overview of these developments.
