一类数列的收斂性及其极限计算式

本文研究一类线性递归数列的收敛性,并给出其极限的简单计算式。     

非线性映射在有界区域的零点数目的若干结果

本文利用连续同伦方法讨论非线性映射在有界区域内零点的存在性和零点数目，以及推广若干经典定理。     

MASS ATTENUATION COEFFICIENTS FOR ELEMENTS MEASURED WITH CHARACTERISTIC X-RAYS FROM TARGETS EXCITED BY ENERGETIC PROTON

The characteristic X-rays from elemental or compound targets excited by energetic proton are quasi-monochromatic X-ray sources. The advantages of high line/ background ratio, controllable intensity as well as many available energies, make them suitable for applications in many important fields. The total mass attenuation cross sections of yttrium have been systematically measured by using this kind of X-ray source. The accuracy of experimental data has been improved to ±1%, which is much better than that of earlier results. The contributions of the coherent and incoherent scattering crees sections have been calcu-lated in accordance with the present experimental condition. And the total photoelectric cross sections have been obtained by subtracting the scattering cross section from the measured total cross sections. The com-parisons of our experimental results with the available data of earlier investigations as well as with the theo-retical calculations have been presented and discussed.     

喹啉基对二氧四胺大环铜配合物结构和性质的影响

喹啉基对二氧四胺大环铜配合物结构和性质的影响卜显和，安道利，朱志昂，张智慧，陈荣悌（南开大学化学系，天津３００００７１）二氧四胺大环（ｍａｃｒｏｃｙｃｌｉｃｄｉｏｘｏｔｅｔｍａｍｉｎｅ）配体因其独特的结构特点和功能而受到广泛的重视和关注［１］。通过在...     

从《尚书》中看我国上古时期的民族关系

《尚书》亦称为《书》或《书经》,是我国一部上古时代的书。所谓上古时期包括尧舜禹和夏商周两个阶段。即从公元前2297年到前2140年为原始社会;公元前2140年到前627年为奴隶制并逐步过渡到封建社会。本文只是从历史的角度来看我国上古时代(尧舜禹)民族关系的发展。这一部分历史,正是《尚书》的重要贡献,而不是其他文献资料可以代替的。有人说:上古时期原始社会阶段还没有民族而是氏族、部落,至多也不过是部落联盟,不能有民族关系。这种论点是机械地理解民族的概念。应知道民族既是概念,又是     

平面简单闭曲线旋转指标定理的另一证明

在目前可见的资料如[1]、[2]、[3]中,平面简单闭曲线的旋转指标定理都采用H.Hopf在1935年所给出的一种证法,这个证明比较繁难,有些细节不易讲清.本文试图利用简单多边形的性质,给出此定理另一较简易的证明.