The manual design of addendum surfaces on common CAD platforms is very tedious which requires many trialscorrections,which will certainly a ect the construction e ciency and quality of addendum surfaces,and then a ect...The manual design of addendum surfaces on common CAD platforms is very tedious which requires many trialscorrections,which will certainly a ect the construction e ciency and quality of addendum surfaces,and then a ect the formability and quality of the workpiece in the process of sheet forming.In this paper,an automatic procedure based on parametric design method is proposed for the rapid construction of the addendum surfaces.The kernel of the parametric method is constructing boundary curves based on the shape of surfaces of workpiece and designing guide curves based on Hermite curve interpolation.By some simple parameters,the shape of the addendum surfaces could be controlled and adjusted easily.In addition,a minimum energy optimization method is employed to further optimize the constructed addendum surface.A finite element analysis for the sheet forming process is performed to evaluate the forming quality of constructed addendum surfaces.The instance illustrates that the addendum surface constructed by the proposed method could ensure both the overall smoothing of surfaces and the final forming quality,and it has a good e ect on springback after forming.This research proposes a smoothing parametric design method for addendum surfaces construction which could construct and optimize addendum surfaces rapidly.展开更多
CCl_3SO_2Br used as a 'telogen' reacts with CH_2=CF_2 to give mainly the 'mono- adduct' CCl_3CH_2CF_2Br, together with very small amouats of CCl_3CF_2CH_2Br, CCl_2BrCH_2CF_2Br and the 'di-adduct...CCl_3SO_2Br used as a 'telogen' reacts with CH_2=CF_2 to give mainly the 'mono- adduct' CCl_3CH_2CF_2Br, together with very small amouats of CCl_3CF_2CH_2Br, CCl_2BrCH_2CF_2Br and the 'di-adduct' CCl_3(CH_2CF_2)_2Br. The result indicates that CCl_3SO_2Br can be used as an addendum in trichloromethyl-bromo-addition reactions to olefins.展开更多
The phase Pw（x） defined by Eq. （3） in the paper as- sociated with the generalized U1b symmetry should be corrected and completely specified as follows：
With a focus on the design of tooth profiles of non-circular gears with addendum modifications that conform to the given complex transmission ratio curves and based on a series of discrete point sets on the pitch curv...With a focus on the design of tooth profiles of non-circular gears with addendum modifications that conform to the given complex transmission ratio curves and based on a series of discrete point sets on the pitch curves,the criteria for tooth profile distortion and undercut in non-circular gears were proposed.With the constraint of no tooth profile distortion and undercut,the addendum modification coefficient was introduced into the calculation of the distorted and undercut segments of the tooth profile of a non-circular gear,and the addendum modification coefficient of each contact point of the non-circular gear was obtained.Based on the generating principle for gear shaping with gear cutters,a theoretical model for calculating the tooth profile of non-circular gears with addendum modification was derived.The cutting and radial feeding motions of the pinion cutter were ignored,and only the meshing motion was considered.The involute tooth profiles of the pinion cutter enveloped the tooth profile of the non-circular gear.3D automatic non-circular gear model generation software was developed,which was a secondary development product of the software UG.A non-circular gear in a rice potted seedling transplanting mechanism was designed,and the transplanter was developed and tested.The test results showed that the designed tooth profile of non-circular gear achieved the variable transmission ratios required by the transplanting mechanism.When the transplanting efficiencies were 140 plants/min,160 plants/min and 180 plants/min,the transplanter completed the rice potted seedling transplanting operation with high quality.展开更多
The force between a gigantic sphere with baryon galaxies exerted on an idealized point-like supernova is given by Fcbf = F1 in Eq. （40） of the original paper. We can generalized the point-like supernova to a sphere ...The force between a gigantic sphere with baryon galaxies exerted on an idealized point-like supernova is given by Fcbf = F1 in Eq. （40） of the original paper. We can generalized the point-like supernova to a sphere with a radius Rs and a constant mass density Ps.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.61471024)National Natural Science Foundation for Young Scientists of China(Grant No.51705469).
文摘The manual design of addendum surfaces on common CAD platforms is very tedious which requires many trialscorrections,which will certainly a ect the construction e ciency and quality of addendum surfaces,and then a ect the formability and quality of the workpiece in the process of sheet forming.In this paper,an automatic procedure based on parametric design method is proposed for the rapid construction of the addendum surfaces.The kernel of the parametric method is constructing boundary curves based on the shape of surfaces of workpiece and designing guide curves based on Hermite curve interpolation.By some simple parameters,the shape of the addendum surfaces could be controlled and adjusted easily.In addition,a minimum energy optimization method is employed to further optimize the constructed addendum surface.A finite element analysis for the sheet forming process is performed to evaluate the forming quality of constructed addendum surfaces.The instance illustrates that the addendum surface constructed by the proposed method could ensure both the overall smoothing of surfaces and the final forming quality,and it has a good e ect on springback after forming.This research proposes a smoothing parametric design method for addendum surfaces construction which could construct and optimize addendum surfaces rapidly.
文摘CCl_3SO_2Br used as a 'telogen' reacts with CH_2=CF_2 to give mainly the 'mono- adduct' CCl_3CH_2CF_2Br, together with very small amouats of CCl_3CF_2CH_2Br, CCl_2BrCH_2CF_2Br and the 'di-adduct' CCl_3(CH_2CF_2)_2Br. The result indicates that CCl_3SO_2Br can be used as an addendum in trichloromethyl-bromo-addition reactions to olefins.
文摘The phase Pw（x） defined by Eq. （3） in the paper as- sociated with the generalized U1b symmetry should be corrected and completely specified as follows：
基金This research was financially supported by the National Key Research and Development Program of China(Grant No.2017YFD070800)the Key Research and Development Program of Jiangsu Province(Grant No.BE2018324)and the Opening of Key Laboratory of Modern Agricultural Equipment Technology in Northern Cold Region(Grant No.KF18-04).
文摘With a focus on the design of tooth profiles of non-circular gears with addendum modifications that conform to the given complex transmission ratio curves and based on a series of discrete point sets on the pitch curves,the criteria for tooth profile distortion and undercut in non-circular gears were proposed.With the constraint of no tooth profile distortion and undercut,the addendum modification coefficient was introduced into the calculation of the distorted and undercut segments of the tooth profile of a non-circular gear,and the addendum modification coefficient of each contact point of the non-circular gear was obtained.Based on the generating principle for gear shaping with gear cutters,a theoretical model for calculating the tooth profile of non-circular gears with addendum modification was derived.The cutting and radial feeding motions of the pinion cutter were ignored,and only the meshing motion was considered.The involute tooth profiles of the pinion cutter enveloped the tooth profile of the non-circular gear.3D automatic non-circular gear model generation software was developed,which was a secondary development product of the software UG.A non-circular gear in a rice potted seedling transplanting mechanism was designed,and the transplanter was developed and tested.The test results showed that the designed tooth profile of non-circular gear achieved the variable transmission ratios required by the transplanting mechanism.When the transplanting efficiencies were 140 plants/min,160 plants/min and 180 plants/min,the transplanter completed the rice potted seedling transplanting operation with high quality.
文摘The force between a gigantic sphere with baryon galaxies exerted on an idealized point-like supernova is given by Fcbf = F1 in Eq. （40） of the original paper. We can generalized the point-like supernova to a sphere with a radius Rs and a constant mass density Ps.
