On periodic solutions for even order differential equations

A class of sufficient conditions are obtained for the existence of a unique 2π$2\pi$-periodic solution of even order differential equations, employing an initial value problem.     

基于均匀化理论的多孔板弯曲问题新解

由于密集型分布孔的存在,通常的有限元法不能有效地分析多孔板的弯曲问题.该文基于均匀化理论建立了该类问题的新解法.对含密集型分布的阶梯型圆孔板的分析结果,说明了该文方法是有效的.     

磁流变液组分选择原则及其机理探讨

从关流变液的流变机理及其性能指标出发,探讨了磁流变液组分母液、磁性颗粒、表面活性剂的选择原则及其对磁流变液性能的影响,及磁流变液的分散工艺;并在此基础上,研制成功了一种性能优良的磁流变液,其沉降稳定性较好,长时间（一个月左右）存放基本不沉降。     

斯塔克调制—电旋转激光光谱技术及其应用

采用斯塔克调制电旋转激光光谱技术将由偶然简并能级跃迁产生的电旋转信号从非简并能级跃迁中分离出来，因而简化了转动量子态的跃迁谱线，减少了谱线重叠现象，反映了分子能级受偶然简并斯塔克相互作用以及电四极相互作用的特性，非常适合那些转动谱线密集，微扰严重的多原子分子的光谱测量与分析。本文既给出了这种光谱技术的半经典理论模型，又运用微扰理论解释了用该技术所测的ＮＯ２分子的转动光谱的形成原因和它们的主要特征。     

Homogenization-based method for bending analysis of perforated plate

Owing to the existence of distributed holes, it is difficult to solve the bending problem of perforated plates by the conventional finite element method. A homogenization-based method for this problem is presented in this paper. As an example, the bending analysis of a circular perforated plate with distributed step-wise cylindrical holes is made. The deflection and the fundamental frequency obtained by present method are in good agreement with experimental data, this implies that the method is effective. This project is supported by the National Natural Science Foundation (19602007) and National Outstanding Youth Foundation (19525206).     

New bounds for Perron root of a nonnegative matrix

In this paper, we obtain some new bounds for Perron root of a nonnegative matrix, which are expressed by easily calculated function in element of matrix. These new results generalize and improve the bounds of G. Frobenius [1] and H. Minc [2], and also extend the known results by Liu [6].     

Densely packed overlayer of iron phthalocyanine molecules grown on single-layer graphene

The FePc molecules form a series of order superstructures on single-layer graphene grown on Ru(0001) with increasing molecular coverage.     

铂（铂—铼）与氧化铝相互作用的研究：Ⅰ.氯的作用

采用PASCA、IR、化学分析及微反等技术,研究Pt/Al_2O_3和Pt-Re/Al_2O_3体系中金属与载体之间的相互作用。结果表明:氯在铂、铼与氧化铝之间的相互作用及对催化剂芳构化活性的影响方面起着十分重要的作用。在没有氯存在的情况下,铂(或铂-铼)与氧化铝之间是不存在相互作用的。当浸渍液中存在氯时,铂以[PtCl_6]~(2-)络离子形式取代氧化铝表面上某些活泼OH~-基,生成稳定的金属—载体相互作用复合物(MSIC)。而生成稳定MSIC的合适盐酸浓度为0.4 mol/L。这一结果与文献报导是一致的。 实验结果还表明,在探讨金属与载体之间的相互作用时,非金属元素(如氯等)是一个十分重要而不可忽视的因素。     

Li\''{e}nard 型方程周期边值问题 解的存在唯一性

给出了下列方程 u″(t) ,(u,t)u′(t) g(u,t)=e(t)边值问题周期解的存在唯一性问题的一些新的判定条件.