Using high-speed oil-filled spinning method,high quality micro copper tube with straight grooves（MCTSG） with an outer diameter of 6 mm was obtained.Then,MCTSG with an outer diameter of 3-6 mm was fabricated successf...Using high-speed oil-filled spinning method,high quality micro copper tube with straight grooves（MCTSG） with an outer diameter of 6 mm was obtained.Then,MCTSG with an outer diameter of 3-6 mm was fabricated successfully by multi-pass drawing processing method.The influence of drawing parameters on the forming of micro straight grooves was investigated based on the forming mechanism.The results show that the values of groove depth and width decrease,while the wall thickness increases as the drawing diameter decreases.At the same time,the groove depth and width increase,while the wall thickness decreases as the die angle increases.The drawing force increases as the reduction increases.Excessive copper tube reduction may results in groove folding and segmental teeth.The drawing force decreases firstly and then increases with the increases in die angle.When the die angle α is 16°,the drawing force is the smallest,indicating 16° is the optimal angle.展开更多
The numerical simulation on drawing process of automotive B-pillar was carried out on AutoForm software,and dangerous forming areas were discovered.The processing parameters,such as the layout of drawbeads,blank holdi...The numerical simulation on drawing process of automotive B-pillar was carried out on AutoForm software,and dangerous forming areas were discovered.The processing parameters,such as the layout of drawbeads,blank holding force and the shape of blank,were adjusted and optimized according to the simulation results.Results indicate that the quality defects can be forecast and removed,which improves the stability of forming process.The cost of design is decreased and the research cycle is shortened.It is proved that the drawing process and die design of B-pillar forming are feasible in actual production.展开更多
According to the requirements of designing V-groove pulley transmission, an application development based on AutoCAD environment and using AutoLISP language is presented. As an example of effective solution for CAD ap...According to the requirements of designing V-groove pulley transmission, an application development based on AutoCAD environment and using AutoLISP language is presented. As an example of effective solution for CAD application, the CAD system for V-groove pulley transmission is established.展开更多
We analyze a common feature of p-Kemeny AGGregation（p-KAGG） and p-One-Sided Crossing Minimization（p-OSCM） to provide new insights and findings of interest to both the graph drawing community and the social choice ...We analyze a common feature of p-Kemeny AGGregation（p-KAGG） and p-One-Sided Crossing Minimization（p-OSCM） to provide new insights and findings of interest to both the graph drawing community and the social choice community. We obtain parameterized subexponential-time algorithms for p-KAGG—a problem in social choice theory—and for p-OSCM—a problem in graph drawing. These algorithms run in time O＊（2O（√k log k））,where k is the parameter, and significantly improve the previous best algorithms with running times O.1.403k/and O.1.4656k/, respectively. We also study natural ＂above-guarantee＂ versions of these problems and show them to be fixed parameter tractable. In fact, we show that the above-guarantee versions of these problems are equivalent to a weighted variant of p-directed feedback arc set. Our results for the above-guarantee version of p-KAGG reveal an interesting contrast. We show that when the number of ＂votes＂ in the input to p-KAGG is odd the above guarantee version can still be solved in time O＊（2O（√k log k））, while if it is even then the problem cannot have a subexponential time algorithm unless the exponential time hypothesis fails（equivalently, unless FPT D M[1]）.展开更多
基金Project(U0834002)supported by the Joint Funds of NSFC-Guangdong of ChinaProject(2009ZM0121)supported by the Fundamental Research Funds for the Central Universities,ChinaProjects(LYM09024)supported by Training Program for Excellent Young Teachers with Innovation of Guangdong University,China
文摘Using high-speed oil-filled spinning method,high quality micro copper tube with straight grooves（MCTSG） with an outer diameter of 6 mm was obtained.Then,MCTSG with an outer diameter of 3-6 mm was fabricated successfully by multi-pass drawing processing method.The influence of drawing parameters on the forming of micro straight grooves was investigated based on the forming mechanism.The results show that the values of groove depth and width decrease,while the wall thickness increases as the drawing diameter decreases.At the same time,the groove depth and width increase,while the wall thickness decreases as the die angle increases.The drawing force increases as the reduction increases.Excessive copper tube reduction may results in groove folding and segmental teeth.The drawing force decreases firstly and then increases with the increases in die angle.When the die angle α is 16°,the drawing force is the smallest,indicating 16° is the optimal angle.
文摘The numerical simulation on drawing process of automotive B-pillar was carried out on AutoForm software,and dangerous forming areas were discovered.The processing parameters,such as the layout of drawbeads,blank holding force and the shape of blank,were adjusted and optimized according to the simulation results.Results indicate that the quality defects can be forecast and removed,which improves the stability of forming process.The cost of design is decreased and the research cycle is shortened.It is proved that the drawing process and die design of B-pillar forming are feasible in actual production.
文摘According to the requirements of designing V-groove pulley transmission, an application development based on AutoCAD environment and using AutoLISP language is presented. As an example of effective solution for CAD application, the CAD system for V-groove pulley transmission is established.
基金supported by a GermanNorwegian PPP grantsupported by the Indo-German Max Planck Center for Computer Science (IMPECS)
文摘We analyze a common feature of p-Kemeny AGGregation（p-KAGG） and p-One-Sided Crossing Minimization（p-OSCM） to provide new insights and findings of interest to both the graph drawing community and the social choice community. We obtain parameterized subexponential-time algorithms for p-KAGG—a problem in social choice theory—and for p-OSCM—a problem in graph drawing. These algorithms run in time O＊（2O（√k log k））,where k is the parameter, and significantly improve the previous best algorithms with running times O.1.403k/and O.1.4656k/, respectively. We also study natural ＂above-guarantee＂ versions of these problems and show them to be fixed parameter tractable. In fact, we show that the above-guarantee versions of these problems are equivalent to a weighted variant of p-directed feedback arc set. Our results for the above-guarantee version of p-KAGG reveal an interesting contrast. We show that when the number of ＂votes＂ in the input to p-KAGG is odd the above guarantee version can still be solved in time O＊（2O（√k log k））, while if it is even then the problem cannot have a subexponential time algorithm unless the exponential time hypothesis fails（equivalently, unless FPT D M[1]）.
