公共图书馆如何吸引读者参与读者活动

近年来,政府加大了对公共图书馆事业的投入力度,公共图书馆不再仅限于传统的图书借还功能,组织举办读者活动已成为图书馆的重点工作. 分析了公共图书馆举办的读者活动引不起读者兴趣的原因,提出了解决这一问题的对策和建议.     

一个包含Smarandache Ceil函数的对偶函数的方程

利用初等方法研究了一个包含Smarandache Ceil函数Sk(n)的对偶函数-Sk(n),给出了当k=6时方程-S6(1)+-S6(2)+…+-S6(n)=6Ω(n)的具体正整数解。     

金属间化合物(Mg,Zn)_(12)Ce与(Mg,Zn)_(11)Ce的研究

对300℃时Mg-Zn-Ce系富镁侧化合物的成分特征、结构和相平衡关系进行了研究.结果表明,Mg-Zn-Ce富镁角存在一个Mg12Ce的二元置换固溶体(Mg,Zn)12Ce,还存在一个三元线性化合物(Mg,Zn)11Ce(τ相).(Mg,Zn)12Ce中Zn的范围为0~7.3%(原子分数),其晶体结构为体心四方晶格.三元线性化合物τ相含Zn为8.5%~43.5%(原子分数),其晶体结构为C底心正交晶格.(Mg,Zn)12Ce和τ相均与α(Mg)存在稳定的两相平衡,且在Mg-Zn-Ce系富镁角还存在三相平衡Mg+(Mg,Zn)12Ce+τ.     

化学方程式配平的矩阵解法

基于矩阵解方程的理论，定义出了一个化学元素矩阵，从而找到了一种配平化学方程式的新方法，称之为矩阵解法。     

一种特殊递推关系序列的判断及求解

对于特征多项式为C(x) =(x- 1) r的特殊递推序列an,给出了它的通解求法以及判定它的充要条件 :存在整数r≥ 1,对任意的n≥ 0 ,Δran =0成立。其中Δran 为递推序列 {an}的r阶差分。     

Efficient Collocation Schemes for Singular Boundary Value Problems

We discuss an error estimation procedure for the global error of collocation schemes applied to solve singular boundary value problems with a singularity of the first kind. This a posteriori estimate of the global error was proposed by Stetter in 1978 and is based on the idea of Defect Correction, originally due to Zadunaisky. Here, we present a new, carefully designed modification of this error estimate which not only results in less computational work but also appears to perform satisfactorily for singular problems. We give a full analytical justification for the asymptotical correctness of the error estimate when it is applied to a general nonlinear regular problem. For the singular case, we are presently only able to provide computational evidence for the full convergence order, the related analysis is still work in progress. This global estimate is the basis for a grid selection routine in which the grid is modified with the aim to equidistribute the global error. This procedure yields meshes suitable for an efficient numerical solution. Most importantly, we observe that the grid is refined in a way reflecting only the behavior of the solution and remains unaffected by the unsmooth direction field close to the singular point.     

具粘性双曲型方程组解的整体存在性

对于具粘性双曲型方程组Cauchy问题，通过引进Lax熵-熵流对的方法，得到了解的整体存在性，利用补偿紧致的方法证明了L∞逼近解的收敛性.     

A possible counterexample to well posedness of entropy solutions and to Godunov scheme convergence

A particular case of initial data for the two-dimensional Euler equations is studied numerically. The results show that the Godunov method does not always converge to the physical solution, at least not on feasible grids. Moreover, they suggest that entropy solutions (in the weak entropy inequality sense) are not well posed.

     

非负定阵元素的扰动和正定完备化

在保持非负定性不变的前提下,本文对矩阵每一元素容许多大的扰动作了进一步的研究, 将本文的结论和C．R．Johnson提出的部分正定阵的正定完备化进行比较,容易发现对已知的正定矩阵求扰动,本文的结论比用C．R.Johnson的正定完备化计算扰动形式上更简单,同时也给出了不同于C．R．Johnson的部分正定阵的正定完备化表示的另外一个公式,推出了这些正定完备化矩阵应具有的若干性质．     

Banach空间中一类强非线性发展方程的反周期解

本文讨论一类强非线性发展方程的反周期解的存在性。针对一大类既含有单调非线性算子又含有非单调非线性算子的发展方程。我们巧妙地结合单调算子理论与Leray-Schauder不动点理论，证明了其反周期解的存在性。最后，举例说明理论结果在2m阶拟线性抛物型方向的时间反周期问题中的应用。