An approach of simultaneous strategies with two novel techniques is proposed to improve the solution accuracy of chemical dynamic optimization problems. The first technique is to handle constraints on control vari- ab...An approach of simultaneous strategies with two novel techniques is proposed to improve the solution accuracy of chemical dynamic optimization problems. The first technique is to handle constraints on control vari- ables based on the finite-element collocation so as to control the approximation error for discrete optimal problems, where a set of control constraints at dement knots are integrated with the procedure for optimization leading to a significant gain in the accuracy of the simultaneous strategies. The second technique is to make the mesh refine- ment more feasible and reliable by introducing length constraints and guideline in designing appropriate element length boundaries, so that the proposed approach becomes more efficient in adjusting dements to track optimal control profile breakpoints and ensure accurate state and centrol profiles. Four classic benchmarks of dynamic op- timization problems are used as illustrations, and the proposed approach is compared with literature reports. The research results reveal that the proposed approach is preferz,ble in improving the solution accuracy of chemical dy- namic optimization problem.展开更多
The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by...The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.展开更多
One of the threats to the modem men today is the quick change in seasons and unusual fluctuations in temperature Contemporary life is marked with various conditions that make life comparatively different and for that ...One of the threats to the modem men today is the quick change in seasons and unusual fluctuations in temperature Contemporary life is marked with various conditions that make life comparatively different and for that matter difficult for everyone. Amongst many worldly things, like materialism, struggle to survive in the highly competitive urban settings, people tend to consider the merits of cosmopolitanism more than anything else Curiously enough, Sir Philip Sidney＇s sonnets, though written in the 16th century and become milestones of the sonnet tradition in the English Renaissance which are applicable to today＇s global concern of environmentalism. When considered in the light of ecocriticism, Sidney＇s sonnets provide a suitable ground for the modem readers to reevaluate the current situation of the world we live in and the nature that we inherit from our ancestors. This paper aims to analyze some of Sidney＇s selected sonnets from Astrophil and Stella in the light of ecocritical approach to literary works.展开更多
基金Supported by the Joint Funds of NSFC-CNPC of China(U1162130)the International Cooperation and Exchange Project of Science and Technology Department of Zhejiang Province(2009C34008)+1 种基金the National High Technology Research and Development Program of China(2006AA05Z226)the Zhejiang Provincial Natural Science Foundation for Distinguished Young Scientists(R4100133)
文摘An approach of simultaneous strategies with two novel techniques is proposed to improve the solution accuracy of chemical dynamic optimization problems. The first technique is to handle constraints on control vari- ables based on the finite-element collocation so as to control the approximation error for discrete optimal problems, where a set of control constraints at dement knots are integrated with the procedure for optimization leading to a significant gain in the accuracy of the simultaneous strategies. The second technique is to make the mesh refine- ment more feasible and reliable by introducing length constraints and guideline in designing appropriate element length boundaries, so that the proposed approach becomes more efficient in adjusting dements to track optimal control profile breakpoints and ensure accurate state and centrol profiles. Four classic benchmarks of dynamic op- timization problems are used as illustrations, and the proposed approach is compared with literature reports. The research results reveal that the proposed approach is preferz,ble in improving the solution accuracy of chemical dy- namic optimization problem.
基金Under the auspices of the National Natural Science Foundation of China (No. 30570303)
文摘The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.
文摘One of the threats to the modem men today is the quick change in seasons and unusual fluctuations in temperature Contemporary life is marked with various conditions that make life comparatively different and for that matter difficult for everyone. Amongst many worldly things, like materialism, struggle to survive in the highly competitive urban settings, people tend to consider the merits of cosmopolitanism more than anything else Curiously enough, Sir Philip Sidney＇s sonnets, though written in the 16th century and become milestones of the sonnet tradition in the English Renaissance which are applicable to today＇s global concern of environmentalism. When considered in the light of ecocriticism, Sidney＇s sonnets provide a suitable ground for the modem readers to reevaluate the current situation of the world we live in and the nature that we inherit from our ancestors. This paper aims to analyze some of Sidney＇s selected sonnets from Astrophil and Stella in the light of ecocritical approach to literary works.
