简介:给出张量积Said-Ball曲面降多阶逼近的一种方法.该方法根据原张量积Said-Ball曲面Pn,m(u,v)与降多阶张量积Said-Ball曲面Qn1,m1(u,v)(n1≤n-1,m1≤m-1)在最小二乘范数下的距离函数在单位正方形[0,1]×[0,1]上取最小值,从而得到了用矩阵表示的降多阶张量积Said-Ball曲面Qn1,m1(u,v)的控制顶点{qij}i^n1=0,^、m}=0的显示表示式.在降多阶过程中,分别考虑了带角点高阶插值条件和不带角点插值条件的情形.文末附有数值例子,并将本文方法与参考文献(9)的方法做了比较.
简介:ThegeneralizedBallcurvesofWang-SaidtypewithapositionparameterLnotonlyunifytheWang-BallcurvesandtheSaid-Ballcurves,butalsoincludeseveralusefulintermediatecurves.ThispaperpresentsthedualfunctionalsforthegeneralizedBallbasisofWang-Saidtype.Therelevantbasistransformationformulaearealsoworkedout.
简介:提出了带形状参数的n次Wang-Ball调配函数,它是n次Wang-Ball基函数的扩展,它具有与n次Wang-Ball基函数相似的性质。基于给出的调配函数,构造了带形状参数的多项式曲线。参数λ具有明确的几何意义,当λ增大时,曲线将逼近于控制多边形,当λ=0时,即退化为n次Wang-Ball调配函数,它为曲线设计提供了一种有效的方法。
简介:增强氧化钇的铜矩阵composites被干燥的球milling(DBM)准备,分别地,湿球milling(WBM)由火花血浆sintering(SPS)列在后面。它是为制作Cu-Y2O3composites。它被发现那Cu-Y2O3composites由DBM综合了展出更好的densification,机械、电的性质比那些由WBM。在由DBM的体积composites的加强的更少的凝块为更好的表演负责。为了推进,理解Y2在由DBM的体积的O3,准备粉末的形态学被调查并且分析。更高的球冲击能和矩阵表面上的铜氧化物的形成在DBM过程期间贡献小矩阵粒子,它为更少的凝块是有益的。
简介:Nowadays,withthedevelopmentofspinningprocesses,moreandmoresystematicresearchaboutspinningparametershasbeenpublished.Basedontheseresults,aroutingabouthowtoselectspinningparametershasbeengraduallyformed.However,ballspinning,duetoitsownfeaturesplusresearchlack,isstillunclearaboutitsparameterselections.Inaddition,somemanufacture-enterprisesonlynoticetheuseofthistechniquewhereasignorethetheorycreation.Theoptimalparametersabouttheballspinningalthoughhavebeenreleasedfromtheseenterprisesbutinfactnotahelpfultheoryforotherresearchersandproducers.Focusonselectingtheparametersbasedonthetrial-and-error,thisarticlehascarriedaseriesofexperimentstostudytheinfluenceonthespinningworkingcoursefromthoseparameters,especiallythepeelingphenomena,andthetubediameterbulging.Anoptimalgraphoftheworkingangle,theaxialfeedingrate,andtheacceptableworkingcourseisputforward.Additionally,basedonthetheoryoftheminimalreductionrate,theselectionoftheballdiameterisfinallydescribed.Thus,ithasgiventherulestogettheproperparametersinballspinning.