Memory Effect in Ceramic Superconductors

We measured the time decay of the magnetic moment of high T_c superconductors YBa₂Cu₃O_7-δ ceramic samples and found the memory effect which has hitherto been reported only in single crystals. The temperature and field ranges, especially the memory phenomenon in ceramic samples at liquid nitrogen temperature can only be understood in a combined picture of both flux creep and glass behaviour     

电热原子吸收光谱法中原子形成机理的热力学和动力学研究

本文对电热原子吸收光谱法（ＥＴＡＡＳ）中气态原子形成机理的热力学和动力学研究状况进行了评述，引用文献６２篇。     

碱金属掺杂富勒烯超导体的临界温度和约化能隙研究

碱金属掺杂富勒烯与传统的超导体情况不同，它有一个很宽区域的声子谱，其最高频率和最低频率分别与费密能Ｅ_F和零温超导能隙△₀为同一数量级，这必将导致对原来强耦合超导电性理论的修正。本文在此情况下求解Ｅｌｉａｓｈｂｅｒｇ方程，得到Ｔ_c和△₀的表达式。结果表明，分子间的低频振动模和分子上的高频振动模同样参与电声耦合，Ｔ_c主要取决于声子谱中高频成份的贡献，而△₀的增加主要取决于声子谱中 关键词：     

反散射理论导出极低能量下的e-He相互作用势

以入射能量为２ｅｙ的ｅ－Ｈｅ弹性散射微分截面的实验数据为基础，运用反散射方法，理论上导出了ｅ－Ｈｅ的相互作用势。用这样的相互作用势计算能量为２和５ｅｖ时的弹性微分截面。所得结果表明，ＷＫＢ反散射方法对极低能情况是失效的，但量子反散射方法仍然非常成功。在极低能情况下，量子反散射方法得到的ｅ－Ｈｅ相互作用势是实数和定域的，呈现出强Vａｎ ｄｅｒ Ｗａａｌｓ势的特征，能给出符合实验数据的结果。     

变系数波动方程所决定的控制系统的最小能量控制和快速控制问题

本文研究变系数波动方程所决定的控制系统的最小能量控制和快速控制问题 .在所讨论的系统精确可控的前提下 ,得到了系统的最小能量控制和快速控制的解析表达式     

关于可达矩阵的求法探讨

在《离散数学》、《图论》课程中 ,用矩阵表示图时 ,涉及到一类重要的矩阵——可达矩阵 ,它是判别图中任意两点是否有通路的重要手段 ,也是求强分图的重要方法 ,但是可达矩阵的求法比较复杂 .本文针对这一问题 ,对可达矩阵的求法进行了改进 ,提出了一种简单可行的算法 .     

椭球约束下误差方差非负二次估计的可容许性

本文给出了线性模型中椭球约束下，误差方差非负二次估计可容许的一个必要条件，并且，对于线性模型中设计阵X＝1nj=(1,1,…，1）′的特殊情形，本文给出了一个充要条件。     

关于5-正则图的强协调性

构造了若干个 5 -正则图的强协调值 ,从而证明它们都是强协调的     

Lie Symmetrical Hojman Conserved Quantity of Relativistic Mechanical System

In this paper, we study the Lie symmetrical Hojman conserved quantity of a relativistic mechanical system under general infinitesimal transformations of groups in which the time parameter is variable. The determining equation of Lie symmetry of the system is established. The theorem of the Lie symmetrical Hojman conserved quantity of the system is presented. The above results are generalization to Hojman's conclusions, in which the time parameter is not variable and the system is non-relativistic. An example is given to illustrate the application of the results in the last.     

Hard X-ray one dimensional nano-focusing at the SSRF using a WSi2 /Si multilayer Laue lens

The multilayer Laue lens (MLL) is a novel diffraction optics which can realize nanometer focusing of hard X-rays with high efficiency. In this paper, a 7.9 μm-thick MLL with the outmost layer thickness of 15 nm is designed based on dynamical diffraction theory. The MLL is fabricated by first depositing the depth-graded multilayer using direct current (DC) magnetron sputtering technology. Then, the multilayer sample is sliced, and both cross-sections are thinned and polished to a depth of 35-41 μm. The focusing property of the MLL is measured at the Shanghai Synchrotron Facility (SSRF). One-dimensional (1D) focusing resolutions of 205 nm and 221 nm are obtained at E=14 keV and 18 keV, respectively. It demonstrates that the fabricated MLL can focus hard X-rays into nanometer scale.