旋转球与非旋转球运动的力学原理

从足球、排球的击球方式和流体动力性能出发，建立力学模型，讨论了旋转球与非旋转球运动的力学原理，得到了弧线球的运动规律及其横向飘移的定量结果。     

WTO与建立政府采购制度的关系

阐述了我国加入WTO后建立政府采购制度的作用与意义，提出建立政府采购制度。可强化企业市场竞争意识，为参与国际竞争打下基础，在符合国际惯例的前提下，最大限度地维护本国利益。     

Are the invariance principles really truly Lorentz-covariant?

It is shown that some sections of the invariance (or symmetry) principles, such as the space reversal symmetry (or parityP) and time reversal symmetryT (of elementary particle and condensed matter physics, etc.), are not really truly Lorentz covariant and hence are dependent on the chosen inertial frame; while the world parity or the proper parityW (i.e., the spacetime reversal symmetryPT) is a truly Lorentz covariant concept, the same for all inertial observers. The basic reason for this is that in theMinkowskian space-time continuum frames of special relativity (in contrast to the space and time frames) one cannot change either space or time keeping the other one fixed and also maintain the causality requirements that all world space mappings should be timelike. Indeed, I find that the Dirac-Wigner and Lee-Yang, etc. sense of Lorentz invarianceis not in full compliance with the Einstein-Minkowskirequirements of the Lorentz covariance (in conjunction with the causality requirements) of all physical laws (i.e., the worldspaceMach principle).     

加强采购管理提高企业经济效益

文章阐述了实施“阳光不购进战略”，从而使企业经营成本下降，提高了企业经济效益。     

一类非线性散度形椭圆方程的最大值原理

文中运用 Hopf最大值原理 ,获得了具有 Dirichlet,Neumann和 Robin边界条件的非线性散度形椭圆方程 ( v( q) u,i) ,i+ w( q) f ( x,u) =0 ( q=| u| 2 ) 的解的函数的最大值原理 ,运用文中获得的最大值原理能够推出某些重要物理量的界的估计 .     

机构构件位移协调原理的研究

通过对过约束机构的静不定次数进行研究，进而对机构构件的位移协调原理进行研究，推导出机构构件位移协调方程。     

谈商务英语应用文写作

商务英语应用在外贸业务和商务活动中使用广泛而频繁。就其体而言，英语应用不同于诗歌、散等学作品，具有特殊的语言风格、惯用格式和专用的词汇与语句。要提高商务英语学习运用英语的能力，我们必须从商务英语的应用性和实践性角度了解商务英语应用的语言特点、写作原则、写作要点和方法。     

瞬态热响应的条元半解析法

由卷积型变分原理出发，针对二维瞬态热响应问题，在空间域采用三角函数加补充项的有限条法，在时间域取解析函数，得到求解瞬态热响应的条元半解析法计算列式．     

Weak convergence of weighted empirical type processes under contiguous and changepoint alternatives

Let X₁, X₂,… be independent random variables. We study asymptotic behaviour of two-time parameter empirical type processes based on observations, ranks and sequential ranks. We introduce weight functions and derive the limiting distributions of these processes under the null hypothesis of X_i being identically distributed, as well as under a class of continguous alternatives which can accommodate the possible occurrence of a changepoint in the series of measurements.     

非线性四阶椭圆型方程的极大值原理

文中考察了一类非线性四阶椭圆型方程,构造了其解的某种泛函,导出了该泛函满足极大值原理的条件。由此可得到该方程解、解的梯度及椭圆算子等的估计。