With an elastic negative pole being driven by ultra so nic vibration and being moved along the surface of work-piece compliantly by ro bot, a new kind of effective EDM, the compliant EDM, cuts the electrically condu c...With an elastic negative pole being driven by ultra so nic vibration and being moved along the surface of work-piece compliantly by ro bot, a new kind of effective EDM, the compliant EDM, cuts the electrically condu ctive materials away and polishes work-piece of free-form surface. The study o f the contact force between the end of polishing tool and the surface of work-p iece is the key for the compliant EDM to study its cutting mechanism and to make better use of it. This paper makes a model for the contact force and verifies i t by experiments and simulation based on the theory of elastic body kinetics and dynamic stress concentration. The research work shows that this contact force i s caused by both the electrical impulsion of EDM and the mechanical force of ult rasonic vibration, the discharge frequency of compliant EDM has a much more clos er connection with the vibration frequency of polishing tool rather than the fre quency of ultrasonic vibration.展开更多
In Shakespeare' s Merchant of Venice,Portia is portrayed as a legal expert.Considerable scholarly work has been devoted to the discussion of the play,and Portia' s ruling appears to be supported by a majority ...In Shakespeare' s Merchant of Venice,Portia is portrayed as a legal expert.Considerable scholarly work has been devoted to the discussion of the play,and Portia' s ruling appears to be supported by a majority of scholarly commentary.However,a number of important legal issues regarding the contract represented in the play require immediate attention.This article attempts to re-evaluate Portia' s ruling and the conventional views on Portia as a legal expert by considering the issues in question within a recent framework of law,and will argue that Portia' s role as a legal expert is questionable.Antonio,Bassanio,and Shylock can all ' walk free'.展开更多
文摘With an elastic negative pole being driven by ultra so nic vibration and being moved along the surface of work-piece compliantly by ro bot, a new kind of effective EDM, the compliant EDM, cuts the electrically condu ctive materials away and polishes work-piece of free-form surface. The study o f the contact force between the end of polishing tool and the surface of work-p iece is the key for the compliant EDM to study its cutting mechanism and to make better use of it. This paper makes a model for the contact force and verifies i t by experiments and simulation based on the theory of elastic body kinetics and dynamic stress concentration. The research work shows that this contact force i s caused by both the electrical impulsion of EDM and the mechanical force of ult rasonic vibration, the discharge frequency of compliant EDM has a much more clos er connection with the vibration frequency of polishing tool rather than the fre quency of ultrasonic vibration.
文摘In Shakespeare' s Merchant of Venice,Portia is portrayed as a legal expert.Considerable scholarly work has been devoted to the discussion of the play,and Portia' s ruling appears to be supported by a majority of scholarly commentary.However,a number of important legal issues regarding the contract represented in the play require immediate attention.This article attempts to re-evaluate Portia' s ruling and the conventional views on Portia as a legal expert by considering the issues in question within a recent framework of law,and will argue that Portia' s role as a legal expert is questionable.Antonio,Bassanio,and Shylock can all ' walk free'.
基金National Natural Science Foundation of China(Nos.U2037601,51821001)Key Basic Research Project of the National Basic Strengthening Plan,China(No.2022-xxxx-ZD-093-xx)。
