关于女子撑竿跳高的探讨

本文对女子撑竿跳高运动的可行性进行了讨论,并提出在我国开展女子撑竿运动的初步设想和教学训练提纲。     

On pole assignment of distributed parameter systems with unbounded input elements

In this paper, the pole assignment problem is considered for a class of distributed parameter systems with unbounded input element and with multiple spectral structure. A formula on the spectrum of the closed loop operator is proved and a formula of pole assignment is obtained. Finally, an example concerning a beam vibration is given. This work is supported by the National Natural Sciences Foundation of China and the National Key Project of China, and partly by the Post Doctoral Science Foundation of China and the Youth Science Foundation of Shanxi.     

考虑刚度折减的多棱锥型套接钢管杆挠度及附加弯矩研究

多棱锥型钢管杆广泛应用于城市周边输电线路,管与管之间通常采用法兰连接,套接连接应用不大。鉴于目前对于多棱锥型套接钢管杆挠度的计算方法研究相对较少,本文根据梁的挠曲线微分方程理论,结合套接节点刚度折减,推导出在常见荷载(弯矩M、水平力P和均布力q)作用下多棱锥型套接钢管杆挠度和附加弯矩的计算方法。最后,选取典型套接钢管杆进行对比分析,得出了一些重要结论。本文对套接钢管杆挠度计算进行细致的研究,可作为输电线路钢管杆套接连接设计的参考     

|m| Partial wave treatment for two-dimensional Coulomb-scattering and Regge pole

1 Introduction Though one-dimensional (1D) systems may clearly exhibit many features of quan-tum mechanics, systems with many degrees of freedom provide more opportunities tostudy many other important features, e.g. the degeneracy of energy eigenstates, whichneed a complete set of commuting observables to characterize an energy eigenstate. Inparticular, two-dimensional (2D) systems with two spatial degrees of freedom may ex-hibit symmetries not present in 1D systems, e.g. the rotational symme…     

世界撑竿跳高的发展和对我国赶超先进的初步设想

撑竿跳高是一项历史悠久而又发展较快的田径项目.从1817年世界上出现第一 个撑竿跳高纪录( 2.92 米)到现在已有一百六十余年的厉史.现在的世界纪录已达 5.94 米,这是撑竿跳高史上的第58个世界纪录.目前正在向 6 米大关进军     

线性微分多项式的零点与极点

对Frank-Weissenborn不等式中导数f~((k))能否被替换成一般的线性微分多项式a_0f+a_1f′+…+a_kf~((k))进行了研究,并彻底解决了这一问题.作为此结果的应用,Hayman-Yang不等式等几个已有的定理也得到了推广.例子表明,本文所得到的几个不等式的条件是基本的.     

Partial pole placement with time delay in structures using the receptance and the system matrices

Datta et al. solved the partial pole placement problem for the symmetric definite quadratic eigenvalue problem where part of the spectrum is relocated to predetermined locations and the rest of the spectrum remains unchanged. In this paper, the problem is solved by a hybrid combination of this result and the method of receptances. This allows for the partial assignment of desired poles with no spillover when there is time delay between the measured or estimated state and actuation of the control.     

碳化硅凸非球面反射镜的加工与检测

为了满足凸非球面反射镜加工中的全频段质量控制及光学参数的高精度检验,提出了应用双摆轴极坐标快速非球面加工技术及测杆法控制Hindle法检测光学参数。首先,描述了双摆轴极坐标快速非球面加工技术及设备;然后,介绍了应用测杆法控制Hindle检测法中标准球面镜顶点分别与被检非球面镜顶点及其焦点的光学间隔,并对其控制精度进行了分析;最后,针对Φ158mm的凸非球面,给出了双摆轴加工的检验结果,并对检测精度进行了分析。实验结果表明：应用双摆轴加工工艺在使低频误差快速收敛的同时,可以有效抑制中频误差,其低频误差的控制精度可以稳定地达到λ/30（λ=633 nm）;应用测杆装调Hindle检测光路的控制极限误差为±0.065 mm,两个光学间隔参数的公差分别为±0.22 mm和±0.30 mm。应用双摆轴加工技术实现了凸非球面的快速加工与全频段质量控制,采用Hindle检测凸非球面得到面形精度为0.022λ（RMS,@633 nm）,满足光学设计技术指标要求。     

On the q-Bernstein polynomials of rational functions with real poles

The paper aims to investigate the convergence of the q  -Bernstein polynomials _Bn,q(f;x)$B_{n,q}(f;x)$ attached to rational functions in the case q>1$q>1$. The problem reduces to that for the partial fractions (x−α)^−j${(x-\alpha )}^{-j}$, j∈N$j\in \mathbb{N}$. The already available results deal with cases, where either the pole α   is simple or α≠q^−m$\alpha \ne q^{-m}$, m∈_N0$m\in {\mathbb{N}}_0$. Consequently, the present work is focused on the polynomials _Bn,q(f;x)$B_{n,q}(f;x)$ for the functions of the form f(x)=(x−q^−m)^−j$f(x)={(x-q^{-m})}^{-j}$ with j?2$j?2$. For such functions, it is proved that the interval of convergence of {_Bn,q(f;x)}$\{B_{n,q}(f;x)\}$ depends not only on the location, but also on the multiplicity of the pole – a phenomenon which has not been considered previously.