排序方式: 共有38条查询结果,搜索用时 15 毫秒
1.
采用DEFORM有限元分析软件模拟中阶梯光栅刻划刀具在光栅刻划过程中的应力分布,并结合金刚石晶体解理特征设计了抗磨损刀具刃口取向。当光栅刻划刀具刃尖点受最大摩擦力方向平行于金刚石晶体周期键连(PBC)方向,且刀具Z向载荷垂直于(111)晶面时,定向面与(111)晶面夹角为27°,非定向面与(111)晶面夹角为63°;光栅刻划刀具在72 g负载条件下,刻程超过17 km时,刀具刃口无崩口等缺陷。采用该方法设计的光栅刻划刀具使用寿命大大超出了传统刀具的使用寿命(刻程约0.8 km),证明了中阶梯光栅刻划刀具抗磨损设计方法的合理性和有效性。 相似文献
2.
传统网络DEA方法是将传统DEA方法评价过程中的"黑箱"打开,考虑输入到输出的中间环节,对生产过程中的各个环节分别评价。传统网络DEA方法获得的是相对于有效决策单元评价的结果,但有时可能要相对于非有效决策单元或者非决策单元进行评价,传统网络DEA方法无法解决该类问题。为此给出相对于非有效决策单元或者非决策单元进行评价的基于C~2R模型的广义链式网络DEA模型,并探讨相关性质. 相似文献
3.
给定有向图D(V,E),如果存在一个单射f:V(D)→{0,1,…,|E|}使得对于每条有向边(u,v),诱导函数f′:E(D)→{1,2,…,|E|}是一个双射函数,其中,f′(u,v)=[f(v)-f(u)](mod(|E|+1)),则f称为有向图D(V,E)的优美标号,f′称为有向图D(V,E)的诱导的边的优美标号.本文讨论了有向图n.■m的优美性,并且证明了当m=23且n为偶数时,n.■m是优美有向图. 相似文献
4.
5.
1. IntroductionHypergraphs are most general structure in discrete mathematics. Computer scientistsintroduced the concept of acyclic hypergraphs and proved that acyc1ic hypergraphs are veryuseful in database theory['--']. In [l], a new system of axioms fOr paths, connectivity andcycles of hypergraphs was introduced. In this paper, we wiIl introduce the concepts ofbipartite hypergraphs and Hamiltonian paths and cycles of a hypergraph.Let V be a finite set. n = (V e) is called a hypergraph on … 相似文献
6.
The Breit interaction contains singular terms which may lead to an instability in quark-antiquark bound state calculations. We regularize the Breit interaction by multiplying the singular terms in momentum space by the form factor μ^2/(q^2+μ^2) such that the interaction is not singular at the origin and the intermediate-and long-range parts of the interaction remain unchanged. The singular terms in the Breit potential find their stable contributions in the calculations after being multiplied by the form factor with different powers. Such a regularized Breit potential with a linear and a relativistically corrected confining potential are applied to the study of qq^- bound states. The spectra for most familiar mesons are consistently obtained and agree well with the experimental data. 相似文献
7.
8.
研究自旋和轨道量子数不同的介子之间的质量劈裂对检验夸克势模型非常重要。 在以往的夸克势模型计算中,ηc-J/ψ的质量劈裂都很难达到实验的值。 用正规化形状因子μ2/(q2+μ2), 在对完整的动量空间中的Breit夸克势实施一次正规化下研究了ηc-J/ψ和新介子ηb与Υ(1s)之间的质量劈裂。 结果表明, 正规化形状因子中的屏蔽质量μ应与介子折合质量有关, 当将其展开为介子折合质量的三阶多项式时, 上述介子质量劈裂可以精确重现实验的结果。另外, 由于完整的Breit势包含有自旋-轨道耦合相互作用的项,因而还可以研究χc0,χc1和χc2之间的质量劈裂。 The study of the splittings between the masses of mesons with different spin and orbit quantum numbers is important for checking the quark potential model. In the previous calculations with quark potential models, the splitting between ηc and J/ψ is however too small to the experimental result. In this paper the mass splitting of ηc J/ψ and the splitting between the new meson ηb and Υ(1s) are investigated with the complete Breit quark potential regularized by applying the form factor μ2/(q2+μ2) one time in momentum space. In addition, because the complete Breit potential includes the spin orbit interaction, it can be used to investigate the splittings among χc0, χc1 and χc2. The investigated results indicate that the screen mass μ in the form factor of regularization is related to the reduced mass of meson. The splittings of ηc-J/ψ, ηb Υ, and χc0 χc1 χc2 can reproduce the experimental results with high accuracy when the screen mass is expanded to the third order polynomial of meson reduced mass. 相似文献
9.
给定有向图D(V,E),如果存在一个单射f:V(D)→{0,1,…,|E|}使得对于每条有向边(u,v),诱导函数f':E(D)→{1,2,…,|E|}是一个双射函数,其中,f'(u,v)=[f(v)-f(u)](mod(|E|+1)),则f称为有向图D(V,E)的优美标号,f'称为有向图D(V,E)的诱导的边的优美标号.本文讨论了有向图n·Cm的优美性,并且证明了当m=23且n为偶数时,n·Cm是优美有向图. 相似文献
10.
研究了有向图m→C n 的优美性,利用搜索图的标号的算法与数学证明相结合的方法,证明了有向图4→ Cn 为优美图,其中n为任意正整数。 相似文献