Superconductivity at 36 K in gadolinium-arsenide oxides GdO<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>F<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>FeAs

In this paper we report the fabrication and superconducting properties of GdO_1−x F _x FeAs. It was found that when x is equal to 0.17, GdO_0.83F_0.17FeAs is a superconductor with the onset transition temperature T _c^on ≈ 36.6 K. Resistivity anomaly near 130 K was observed for all samples up to x = 0.17, and such a phenomenon is similar to that of LaO_1−x F _x FeAs. Hall coefficient indicates that GdO_1−x F _x FeAs is conducted by electron-like charge carriers. Recommended by Prof. Nie Yuxin, Executive Editor of Science in China Series G-Physics, Mechanics & Astronomy Supported by the National Natural Science Foundation of China (Grant Nos. 10221002/A0402 and 10774170/A0402), the National Basic Research Program of China (973 Program) (Grant Nos. 2006CB601000, 2006CB921107 and 2006CB921802), and the Chinese Academy of Sciences (ITSNEM)     

对物理实验课程兴趣的分析和研究

讨论了在校大学生对物理实验课程学习的现状,以及应采取什么方法去引导和激发学生的学习兴趣。     

波前功率谱密度函数评价方法探讨

 波前功率谱密度PSD（Power Spectral Density）能定量给出波前畸变的空间频率分布、限定波纹度和粗糙度指标，全面反映ICF驱动器对高功率激光光学元件加工质量的特殊要求。给出了波前功率谱密度PSD的定义及计算方法，并使用大口径相移干涉仪作为波前检测仪器，对光学磷酸盐钕玻璃透射波前进行了测试实验，获得波前一维PSD分布，证实功率谱密度为高功率激光光学元件波前参数的一种有效表征方式。同时，还对PSD与均方根RMS之间的关系进行了初步的讨论。     

Synthesis of autophotosensitive hyperbranched polyimides based on 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 1,3,5‐tris(4‐aminophenoxy)benzene via end capping of the terminal anhydride groups by ortho‐alkyl aniline

Benzophenone‐containing, anhydride‐terminated hyperbranched poly(amic acid)s were end‐capped by ortho‐alkyl aniline in situ and then chemically imidized, yielding autophotosensitive hyperbranched polyimides. The polyimides were soluble in strong polar solvents, such as N‐methyl‐2‐pyrrolidone, N‐dimethylformamide, dimethylacetamide, and dimethyl sulfoxide. Thermogravimetric analysis revealed their excellent thermal stability, with a 5 wt % thermal loss temperature in the range of 527–548 °C and a10 wt % thermal loss temperature in the range of 562–583 °C. The strong absorption of the polyimide films in ultraviolet–visible spectra at 365 nm indicated that the hyperbranched polyimides were patternable. Highly resolved images with a line width of 6 μm were developed by ultraviolet exposure of the polymer films. A well‐defined image with lines as thin as 3 μm was also patterned, but the lines were rounded at the edges. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 2026–2035, 2003     

树枝状醚酰胺多官能团(甲基)丙烯酸酯低聚物的合成及其紫外光固化性能的研究

合成了树枝状(甲基)丙烯酸化醚酰胺低聚物,采用拉曼光谱、光-差热分析和动态力学热分析方法对其紫外光固化动力学和固化膜热机械性能进行了研究.结果表明,这种树枝状低聚物在紫外光照下双键转化率可达80%以上,且其最大反应速率、固化膜的软化温度和玻璃化转变温度随双键浓度的增大而提高.     

Airy函数的零点分布

作为二阶微分方程 f″-zf=0的解 ,Airy函数有可列个零点且均为负数 ,本文借助 Macdonal函数 ,证明了这一重要结论 .其证明过程不涉及整函数阶的问题 ,是一种较为初等的证明方法 .     

平面Laplace外边值问题

证明平面调和函数的Dirichlet外问题解存在唯一的充要条件,在此基础上,确立外问题的等价边界积分方程,首次给出外域上的极值原理,对第一类Fredholm边界的积分方程的可解性进行了讨论。     

实验研究具有周向抽吸轴对称射流的拟序结构

基于实验研究具有周向抽吸轴对称射流拟序结构的动力学行为,定义了临界出口主速度以及超临界工况（低速工况）和亚临界工况。提出了超临界工况下,拟序结构的空间演化特征。基于功率谱确定了超、亚临界工况流动系统发生自激励振荡的速度比范围。