In order to form an emergency control policy table quickly, this paper proposes a fast algorithm of emergency control named ＂micro-step discrete method＂, which is based on the physical meaning of the gradient and th...In order to form an emergency control policy table quickly, this paper proposes a fast algorithm of emergency control named ＂micro-step discrete method＂, which is based on the physical meaning of the gradient and the discrete characteristics of emergency control. Then it is improved through the stability criterion, integral step, and micro-step factor. This paper takes generator-shedding as the emergency control measures. As the optimal generator-shedding control is essentially an optimal control problem and the generator-shedding variables are always constant, it is convenient to use the control parameter algorithm to solve the problem, which can calculate the gradient of the transient stability function to control variables.展开更多
Ultra-precision machining has been well known as a very precise and effective way to prototype and fabricate different types of components with microstructures.In this paper,an ultra-precision micro-milling method has...Ultra-precision machining has been well known as a very precise and effective way to prototype and fabricate different types of components with microstructures.In this paper,an ultra-precision micro-milling method has been presented to produce a micro-step pillar array as an embossing mold for semiconductor application.Theoretical analysis on machining mechanics indicates that work material property,machining strategy,and cutting tool geometry largely afFect machining distortion on the machined microstructure.Experimental investigation has been conducted on micromachining of the micro-step pillar array using different types of cutting tools and work materials.Experimental results demonstrate that the material property,cutting tool edge radius,and cutting force play a significant role in the machined micro-structure accuracy and surface finish,while grain boundary of brass has no significant effect on the micro-milling performance.The best outcome among the tests done is achieved when using brass as work material and cutting with a straight-edge single crystalline diamond tool.The main reasons to achieve this outcome are based on:the brass material having a higher elastic modulus and the diamond tool having a smaller cutting edge radius,which contributes to better machinability of brass.One micro-step pillar array has been successfully obtained with very precise feature and dimensional accuracy using brass work material and single-crystal diamond tool.It is believed that the outcomes of this study would largely benefit the research community and end-users.展开更多
文摘In order to form an emergency control policy table quickly, this paper proposes a fast algorithm of emergency control named ＂micro-step discrete method＂, which is based on the physical meaning of the gradient and the discrete characteristics of emergency control. Then it is improved through the stability criterion, integral step, and micro-step factor. This paper takes generator-shedding as the emergency control measures. As the optimal generator-shedding control is essentially an optimal control problem and the generator-shedding variables are always constant, it is convenient to use the control parameter algorithm to solve the problem, which can calculate the gradient of the transient stability function to control variables.
文摘Ultra-precision machining has been well known as a very precise and effective way to prototype and fabricate different types of components with microstructures.In this paper,an ultra-precision micro-milling method has been presented to produce a micro-step pillar array as an embossing mold for semiconductor application.Theoretical analysis on machining mechanics indicates that work material property,machining strategy,and cutting tool geometry largely afFect machining distortion on the machined microstructure.Experimental investigation has been conducted on micromachining of the micro-step pillar array using different types of cutting tools and work materials.Experimental results demonstrate that the material property,cutting tool edge radius,and cutting force play a significant role in the machined micro-structure accuracy and surface finish,while grain boundary of brass has no significant effect on the micro-milling performance.The best outcome among the tests done is achieved when using brass as work material and cutting with a straight-edge single crystalline diamond tool.The main reasons to achieve this outcome are based on:the brass material having a higher elastic modulus and the diamond tool having a smaller cutting edge radius,which contributes to better machinability of brass.One micro-step pillar array has been successfully obtained with very precise feature and dimensional accuracy using brass work material and single-crystal diamond tool.It is believed that the outcomes of this study would largely benefit the research community and end-users.
