关于曲率积分不等式的注记

本文主要研究平面卵形线的曲率积分不等式.利用积分几何中凸集的支持函数以及外平行集的性质,得到了Gage等周不等式与曲率的熵不等式的一个积分几何的简化证明;进一步地,我们得到了一个新的关于曲率积分的不等式.     

子流形的具有位置向量方向外力场的平均曲率流

考虑欧氏空间R~(n+p)中n(≥2)维闭子流形沿平均曲率向量场加上一个位置向量方向外力场的流的发展.设子流形任意一点处平均曲率向量非零和第二基本形式的模长以平均曲率向量长度的常数倍(仅与n有关)为界,我们证明了若外力场很小时,拼挤子流形要么在有限时间内收缩为一点,要么子流形在任意时刻都存在;若外力场足够大时,子流形发散到无穷大;同时,当流发展到极限位置时,规范化子流形都光滑收敛到R~(n+p)中的一个n+1维子空间中的标准球面.     

径向截面曲率有下界黎曼流形的微分同胚定理

研究了径向截面曲率以一类旋转模曲面的Gauss曲率为下界的非紧完备黎曼流形的拓扑,得到了该类黎曼流形与欧氏空间微分同胚的一个合理的充分条件,推广了径向截面曲率有常数下界完备黎曼流形的微分同胚定理.     

向量值优化问题的适定性

将向量值优化问题的适定性理论推广到具有W-距离的拟度量空间中,给出B-适定性及DH-适定性的概念,并得到相应的判别准则．定义一类非线性标量化函数,利用这类标量化函数的性质将向量值优化问题转化为标量值优化问题,得到原问题与标量化问题的适定性之间的等价关系．     

Para-CR Structures of Codimension 2 on Tangent Bundles in Riemann–Finsler Geometry

We determine a 2-codimensional para-CR structure on the slit tangent bundle T0 M of a Finsler manifold（M,F） by imposing a condition regarding the almost paracomplex structure P associated to F when restricted to the structural distribution of a framed para-f-structure.This condition is satisfied when（M,F） is of scalar flag curvature（particularly constant） or if the Riemannian manifold（M,g） is of constant curvature.     

Asymptotic Estimates on the Time Derivative of Φ-entropy on Riemannian Manifolds

In this note,we obtain an asymptotic estimate for the time derivative of the Φ-entropy in terms of the lower bound of the Bakry–Emery Γ2 curvature.In the cases of hyperbolic space and the Heisenberg group(more generally,the nilpotent Lie group of rank two),we show that the time derivative of the Φ-entropy is non-increasing and concave in time t,also we get a sharp asymptotic bound for the time derivative of the entropy in these cases.     

Laguerre isoparametric hypersurfaces in ℝ n with two distinct non-zero principal curvatures

An umbilical free oriented hypersurfacex：M→Rnwith non-zero principal curvatures is called a Laguerre isoparametric hypersurface if its Laguerre form C=i Ciωi=iρ1（Ei（logρ）（r ri）Ei（r））ωi vanishes and Laguerre shape operator S=ρ1（S 1 rid）has constant eigenvalues.Hereρ=i（r ri）2,r=r1＋r2＋···＋rn 1n 1is the mean curvature radius andSis the shape operator ofx.{Ei}is a local basis for Laguerre metric g=ρ2III with dual basis{ωi}and III is the third fundamental form ofx.In this paper,we classify all Laguerre isoparametric hypersurfaces in Rn（n〉3）with two distinct non-zero principal curvatures up to Laguerre transformations.     

非线性再生散度模型的几何结构及其渐近推断

本文基于唐年胜等(1999)对非线性再生散度模型在欧氏空间建立的微分几何结构导出了与估计有关的随机展开以及与统计曲率有关的若干渐近推断,推广了韦博成等人关于非线性回归模型和指数族非线性模型的相应结果.     

灰色相关性分析在结构静力损伤识别中的应用

基于灰色理论的相关性分析方法，首次提出了灰色曲率关联系数的概念并将其应用到结构的静力损伤识别中，提出了对局部损伤十分敏感的静态位移曲率置信因子SDCACi，通过该因子的大小对各节点所连接的单元是否会发生损伤进行精确的判断，然后运用最小二乘法对损伤区域的损伤程度进行识别．并将该方法应用于两端固支梁的损伤识别中，由识别结果可以证明：不论测量数据(用有限元仿真计算并考虑了测量误差)的多少，该方法对结构中的单损伤和多损伤都能进行准确的定位，因此该方法在大型结构及复杂结构的损伤识别中具有广阔的应用前景．     

Effect of rail corrugation on vertical dynamics of railway vehicle coupled with a track

The effect of rail corrugation on the vertical dynamics of railway vehicle coupled with a curved track is investigated in detail with a numerical method when a wheelset is steadily curving. In the calculation of rail corrugation we consider the combination of Kalker‘s rolling contact theory modified, a model of material loss on rail running surface, and a dynamics model of railway vehicle coupled with a curved track. In the establishment of the dynamic model, for simplicity, one fourth of the freight car without lateral motions,namely a wheelset and the equivalent one fourth freight car body above it, is considered. The Euler beam is used to model the rails and the track structure under the rails is replaced with equivalent springs, dampers and mass bodies. The numerical results show the great influence of the rail corrugation on the vibration of the parts of the vehicle and the track, and the some characters of rail corrugation in development.