Jordan函数r次方Jrk(n)的误差项的进一步性质

设k，r分别是自然数和非零整数，Jk(n)是Jordan函数。以E(x；k，r)表示和式sum from (n≤x) Jkr(n)的渐近公式中的误差项，本文研究了E(x；k，r)的某种加权平方积分均值。     

High index of refraction via quantum interference in a three-level system of Er^3＋-doped yttrium aluminium garnet crystal

A simple three-level system is proposed to produce high index of refraction with zero absorption in an Er^3＋-doped yttrium aluminium garnet （YAG） crystal, which is achieved for a probe field between the excited state 4I13/2 and ground state 4I15/2 by adjusting a strong coherent driving field between the upper excited state 4I11/2 and 4I15/2. It is found that the changes of the frequency of the coherent driving field and the concentration of Er^3＋ ions in the YAG crystal can maximize the index of refraction accompanied by vanishing absorption. This result could be useful for the dispersion compensation in fibre communication, laser particle acceleration, high precision magnetometry and so on.     

正项二阶等差数列的不等式

文[1]、[2]研究了正项等差数列方幂的不等式，本文研究由递增正项二阶等差数列若干项构成的不等式，为了简便起见，以下约定{an}是递增正项二阶等差数列，bn=a（n＋1）-an，{bn}的公差为d，其前n项和为Sn，m，k，n，p为正整数．     

核子结构对核物质性质的影响

采用带自相互作用的夸克介子耦合模型(QMC)计算了核物质的一些性质, 得到 密度依赖的标量介子与核子的耦合常数, 并把该耦合常数的变化趋势引入到VDD和SDD中, 即把核子结构的信息引入到了QHD中. 数值结果表明核子的内部结构对核物质性质有显著影响.     

光压效应及其应用

 一、光压效应光的本质是电磁波,电磁波不仅具有能量,而且具有动量。设光子速度为c,频率为v,波长为λ,则光子的能量和动量分别为:E=hv.     

Advances in micro-perforated panel absorbers

Theoretical and experimental investigations on the performance of micro-perforated -panel absorbers are reviewed in this paper. By reviewing recent research work, this paper reveals a relationship between the maximum absorption coefficient and the limit of the absorption frequency bandwidth. It has been demonstrated that the absorption frequency bandwidth can be extended up to 3 or 4 octaves as the diameters of the micro-holes decrease. This has become possible with the development of the technologies for manufacturing micro-perforated panels, such as laser drilling, powder metallurgy, welded meshing and electro-etching to form micrometer order holes. In this paper, absorption characteristics of such absorbers in random fields and in high sound intensity are discussed both theoretically and experimentally. A new absorbing structure based on micro-perforated-panel absorbers demonstrate experimentally high sound absorption capability. This review shows that the micro-perforated-panel absorber has potentials to be one of ideal absorbing materials in the 21st century.     

FeS2多晶薄膜电子结构的实验研究

用磁控溅射方法制各纯Fe薄膜,并硫化合成FeS2.采用同步辐射X射线近边吸收谱与X射线光电子能谱研究了薄膜的电子结构.结果表明,合成的FeS2薄膜,在费米能级附近,有较强的Fe 3d态密度存在,同时,在价带谱中2-10eV处有强度较大的S 3p态密度存在;Fe的3d轨道在八面体配位场作用下分别为t2g和eg轨道,实验中由Fe的吸收谱计算得到两分裂能级之差为2.1eV;实验测得FeS2价带结构中导带宽度约为2.4eV,导带上方仍存在第二能隙,其宽度约为2.8eV.     

关联数列的数表问题

近年来“数表问题”如一颗璀璨的“明珠”，频频出现在国际、国内的数学联赛、中、高考试卷上，它与数列知识联手，凑出一曲曲优美的“乐章”，所谓“数表”就是满足一定条件的数，按一定规律排成一个表，这类问题题型灵活、解法巧妙、规律性强、学生乐见，低、中、高档题均可出现，故成为很多出题专家们的“新宠”，下面就关联数列的数表问题进行分类探究．用以抛砖引玉，期望读者从中受益，进而得出解决此类问题的一般方法。     

精心设计问题培养学生能力

记忆特征告诉我们，要加强对某一件事的记忆，加深对某一问题的理解，“错误”与“教训”是最为深刻的．数学教学何尝不是如此．例如，为了加深学生对等差数列的前n项和公式的理解和应用，在教学中可设计如下两个问题：     

ON THE UNIQUENESS OF THE WEAK SOLUTIONS OF A QUASILINEAR HYPERBOLIC SYSTEM WITH A SINGULAR SOURCE TERM

This paper is a continuation of the authors'previous paper[1].In this paper the authorsprove,assuming additional conditions on the initial data,some results about the existence anduniqueness of the entropy weak solutions of the Cauchy problem for the singular hyperbolicsystem a_t+(au)_x_2au/x=0,u_t+1/2(a~2+u~2)_x=0,x>0,t≥0.