This article brings forward the conception of potential and filed potential in bank's competition under the inspiration of law of electric current in electrodynamics. It discusses the impact of potential shifting ...This article brings forward the conception of potential and filed potential in bank's competition under the inspiration of law of electric current in electrodynamics. It discusses the impact of potential shifting on commercial bank's credit scale and builds up a model for commercial bank to control the scale by credit pricing and risk policy in a dynamic way, and also gives some advice to domestic commercial bank for improving loan business, aiming to settle down the existing credit management problems.展开更多
Continuous glass melting tanks represent thermo-chemical reactors with very complex flow patterns. Controlling the flow patterns within the glass melting tanks with the aim of improving their performance is one of the...Continuous glass melting tanks represent thermo-chemical reactors with very complex flow patterns. Controlling the flow patterns within the glass melting tanks with the aim of improving their performance is one of the glass industry primary challenges. The tank performance is basically determined by the RTD （residence time distribution） of the glass melt, which directly impacts the glass quality and energy distribution. In the present work, numerical simulations are carried out on the electromagnetic flow control to investigate how well the flow can be controlled by externally generated electromagnetic （Lorenz） forces that are added to the glass melt. Furthermore, the melting tanks are equipped with supplementary electric heating systems called ＂electric boosters＂. The desired result would be an improved RTD. The electromagnetic flow control is called ＂electromagnetic boosting＂ and can be realized by exposing the glass bath to an external magnetic field generating Lorentz forces on the glass melt as an additional flow component. The numerical simulations of the present study require coupled calculations of electromagnetic field, flow field, and temperature field, because the material properties of glass melt are strongly temperature-dependent. The computational results show that electromagnetic boosting is an excellent way of improving the RTD in glass melting tanks, ultimately resulting in better glass quality and increased productivity. Of course, the glass industry is highly interested in achieving exactly this result.展开更多
With the formation of the Center for Compact and Efficient Fluid Power （CCEFP） in 2006, there has been a resurgence of academic fluid power research in the USA. The centre’s vision is to make fluid power the techno...With the formation of the Center for Compact and Efficient Fluid Power （CCEFP） in 2006, there has been a resurgence of academic fluid power research in the USA. The centre’s vision is to make fluid power the technology of choice for power generation, transmission, storage, and motion control. To address fluid power’s key technical barriers, the CCEFP research strategy supports and coordinates pre-competitive research in three thrust areas： efficiency, compactness and effectiveness, where effectiveness means making fluid power safer, easier to use, leak free and quiet. This paper reviews some of the most important results from the first decade of CCEFP research.展开更多
Power System Stabilizer (PSS) was proposed during 1960s to solve the low frequency oscillation problem raised by the wide application of the high-gain fast-response exciters. The fundamentals of PSS design lie in the ...Power System Stabilizer (PSS) was proposed during 1960s to solve the low frequency oscillation problem raised by the wide application of the high-gain fast-response exciters. The fundamentals of PSS design lie in the angle compensation to increase the damping torque, which, since then, has become an important principle in designing the various power system dampers, such as SVC, TCSC, UPFC. Although many papers have been dedicated to the application of this principle, it is interesting to note that in the real industry applications PSS parameters have to be carefully tuned on site in spite of its mature design theory. So does the classical PSS design theory really meet the PSS design demand? By combining the frequency domain and the time domain analysis, this paper reinvestigates the basic idea behind the classical PSS design theory. The paper clarifies the con-cepts of the synchronous torque as well as the damping torque and proves that the classical PSS design principles based on these concepts are not theoretically sound. Then the paper discusses the Linear Optimal Controller Design method and ana-lyzes its relations with the conventional PID design. By doing so the paper reveals the real mechanism of the PSS and proposes to use more systematic and advanced control tools to enhance the controller performance.展开更多
文摘This article brings forward the conception of potential and filed potential in bank's competition under the inspiration of law of electric current in electrodynamics. It discusses the impact of potential shifting on commercial bank's credit scale and builds up a model for commercial bank to control the scale by credit pricing and risk policy in a dynamic way, and also gives some advice to domestic commercial bank for improving loan business, aiming to settle down the existing credit management problems.
文摘Continuous glass melting tanks represent thermo-chemical reactors with very complex flow patterns. Controlling the flow patterns within the glass melting tanks with the aim of improving their performance is one of the glass industry primary challenges. The tank performance is basically determined by the RTD （residence time distribution） of the glass melt, which directly impacts the glass quality and energy distribution. In the present work, numerical simulations are carried out on the electromagnetic flow control to investigate how well the flow can be controlled by externally generated electromagnetic （Lorenz） forces that are added to the glass melt. Furthermore, the melting tanks are equipped with supplementary electric heating systems called ＂electric boosters＂. The desired result would be an improved RTD. The electromagnetic flow control is called ＂electromagnetic boosting＂ and can be realized by exposing the glass bath to an external magnetic field generating Lorentz forces on the glass melt as an additional flow component. The numerical simulations of the present study require coupled calculations of electromagnetic field, flow field, and temperature field, because the material properties of glass melt are strongly temperature-dependent. The computational results show that electromagnetic boosting is an excellent way of improving the RTD in glass melting tanks, ultimately resulting in better glass quality and increased productivity. Of course, the glass industry is highly interested in achieving exactly this result.
基金This research in this paper was funded by the Engineering Research Center for Compact and Efficient Fluid Power, supported by the National Science Foundation under Grant No. EEC-0540834.
文摘With the formation of the Center for Compact and Efficient Fluid Power （CCEFP） in 2006, there has been a resurgence of academic fluid power research in the USA. The centre’s vision is to make fluid power the technology of choice for power generation, transmission, storage, and motion control. To address fluid power’s key technical barriers, the CCEFP research strategy supports and coordinates pre-competitive research in three thrust areas： efficiency, compactness and effectiveness, where effectiveness means making fluid power safer, easier to use, leak free and quiet. This paper reviews some of the most important results from the first decade of CCEFP research.
基金supported in part by the National Natural Science Founda-tion of China (Grant Nos. 51077049,50707009)the Beijing Nova Program and in part by "111" Project of China (Grant No. B08013)
文摘Power System Stabilizer (PSS) was proposed during 1960s to solve the low frequency oscillation problem raised by the wide application of the high-gain fast-response exciters. The fundamentals of PSS design lie in the angle compensation to increase the damping torque, which, since then, has become an important principle in designing the various power system dampers, such as SVC, TCSC, UPFC. Although many papers have been dedicated to the application of this principle, it is interesting to note that in the real industry applications PSS parameters have to be carefully tuned on site in spite of its mature design theory. So does the classical PSS design theory really meet the PSS design demand? By combining the frequency domain and the time domain analysis, this paper reinvestigates the basic idea behind the classical PSS design theory. The paper clarifies the con-cepts of the synchronous torque as well as the damping torque and proves that the classical PSS design principles based on these concepts are not theoretically sound. Then the paper discusses the Linear Optimal Controller Design method and ana-lyzes its relations with the conventional PID design. By doing so the paper reveals the real mechanism of the PSS and proposes to use more systematic and advanced control tools to enhance the controller performance.
