求幂级数收敛半径的方法

指出了文 [1 ]中一个考研题的错误解法 ,并给出求幂级数收敛半径的几种方法     

油价波动对国民经济影响模型构建与应用

为了科学构建原油价格波动与国民经济发展的关系,在借鉴国内外专家学者相关模型基础上,考虑不同国民经济指标对油价波动的时滞反馈等因素,构建油价波动对国民经济影响模型.利用原油价格波动对国民经济发展的动态模型,对模型的各部分关系系数进行确定,最后根据所得到的模型对国民经济影响进行实际分析与预测,并得出规避油价波动影响风险的措施.     

Monitoring the Aggregation of Dansyl Chloride in Acetone through Fluorescence Measurements

The aggregation of dansyl chloride (DNS-Cl) in acetone has been studied in detail by steady-state fluorescence techniques.It has been demonstrated that DNS-Cl is stable in acetone during purification and aggregation study processes.The aggregates are not solvolyzed in acetone,and do not take part n any chemical reactions either.It has been found that DNS-Cl tends to aggregate even when its concentration is much lower than its solubility in acetone.The aggregation is reversible,and both the aggregation and the deaggregation are very slow processes.Introduction of SDS has a positive effect upon the formation and stabilization of the aggregates.     

自组装有机分子薄膜的可逆超高密度信息存储

信息技术的迅速发展对信息存储密度提出了越来越高的要求，采用自组装方法研究了有机分子4’-氰基-2，6-二甲基-4-羟基偶氮苯（4’cyano-2，6-dimethyl-4-hydroxy azobenzene）的成膜特性．通过在扫描隧道显微镜的针尖和基底之间加脉冲电压在薄膜上进行信息点的写入，得到了直径为1．8nm的信息点，并分析了信息点形成的机理．     

催化动力学光度法测定痕量钴(Ⅱ)

本法基于钴 (Ⅱ )对高碘酸钾氧化孔雀绿的催化作用 ,提出一种灵敏地测定痕量钴 (Ⅱ )的新方法。该方法线性范围在 0～ 0 8μg·2 5mL- 1 ,检测限为 2 1× 10 - 1 0 g·mL- 1 。测定出反应表现活化能Ea=37 94kJ·mol- 1 。此法用于茶叶、维生素B1 2 中钴的测定 ,结果满意     

应用LiNbO_3声表面波驱动的全光纤声光频移器

介绍一种工作在10.7MHz的全光纤声光频移器.它由在LiNbO_3基片上制作的叉指电极换能器产生的声表面波驱动.当驱动电功率1.5W时,频移光转换效率达35％.     

Surface modifications of ITO electrodes for polymer light-emitting devices

Surface modifications were performed on the indium tin oxide (ITO) substrates for polymer light-emitting devices, using the different treatment methods including solvent cleaning, hydrochloric acid treatment and oxygen plasma. The influence of modifications on the surface properties of ITO electrodes were investigated by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), contact angle, and four-point probe. The surface energies of the ITO substrates were also calculated from the measured contact angles. Experimental results demonstrate that the surface properties of the ITO substrates strongly depend on the modification methods, and oxygen plasma more effectively improves the ITO surface properties compared with the other treatments. Furthermore, the polymer light-emitting electrochemical cells (LECs) with the differently treated ITO substrates as device electrodes were fabricated and characterized. It is observed that the surface modifications on ITO electrodes have a certain degree of influence upon the injection current, luminance and efficiency, but hardly upon the turn-on voltages of current injection and light emission which are close to the measured energy gap of electroluminescent polymer. Oxygen plasma treatment on the ITO electrode yields the better performance of the LECs, due to the improvement of interface formation and electrical contact of the ITO electrode with the polymer blend in the LECs.     

解可分离约束双凹规划问题的一种外逼近方法[英文]

在本文中，我们提出了双凹规划问题和更一般的广义凹规划问题。我们给出了双凹规划问题的整体最优性条件，并构造了一个有限终止外逼近算法。     

半群K(n,r)中的幂等生成元

设Singn是由一个n元集上的所有奇异变换所构成的奇异变换半群，I是由Singn中一些亏数为1的幂等元组成的集合，Howie利用有向图证明了：I是Singn的一个生成集当且仅当与其相应的有向图D（I）是强连通的完全图，本文利用多重有向图将这一结果推广到Singn的每个理想K（,r)上。