密封容器中后处理制备Tl2Ba2CaCu2Oy高温超导薄膜及其性能研究

以铝酸镧（001）单晶为基片，采用两步法制备Tl2Ba2CaCu2Oy（Tl 2212）高 温超导薄膜.首先，利用脉冲激光沉积（PLD）工艺沉积Ba2CaCu2Ox非晶前驱体薄膜；然后，前驱体薄膜在高温（720—850℃）下密封钢容器里铊化结晶形成Tl 2212薄膜.XRD结果表明Tl2212 薄膜是沿c轴方向生长的，其相组成为Tl 2212，摇摆曲线（0012）的半高宽为0.72° ，SEM图像显示其表面光滑平整，其零电阻温度为106.2K. 关键词： Tl 2212超导薄膜 脉冲激光沉积     

Kirchhoff方程的相对常值特解及其Lyapunov稳定性

对于超细长弹性杆静力学的Kirchhoff方程，用动力学的概念和方法研究其常值特解 和稳定性问题.计算了Kirchhoff方程相对固定坐标系、截面主轴坐标系以及中心线Frenet 坐标系的常值特解，进行了Kirchhoff动力学比拟，用一次近似理论分别讨论了它们的Lyapu nov稳定性，导出了若干稳定性判据，并在参数平面上绘出了稳定域. 关键词： 超细长弹性杆 Kirchhoff方程 常值特解 Lyapunov稳定性     

AGSM光束在自由空间中的传输

 用矩阵方法研究了有扭曲的各向异性高斯-尔模型（AGSM）光束通过自由空间的传输。给出了光束参数的解析传输公式和详细数值计算结果，说明AGSM光束的传输特性以及扭曲因子和空间相关长度的影响。     

匹配问题实例空间和解空间结构

本文通过研究匹配问题的实例空间，匈牙利算法和解空间三者之间的关系，指出S实例空间的数目与问题复杂度之间的关系既不是充分也不是必要的，而如何对问题的解空间进行合理的分解才能是问题的关键。     

有界对称域上的Dp乘子

设Ω是Cn中包含原点的有界对称域.本文在Ω上得到了关于Dp空间的两个乘子定理.     

拟议中的21世纪光学望远镜

 不论天文爱好者还是职业天文学家都渴望有一台大的反射镜或透镜,因为它能聚集更多的光,具有显示天体细节的潜能。特别是专业工作者,大仪器是研究宇宙中的暗星系和现代天文学中许多重要问题不可或缺的。可以说望远镜越大越好。现在,大地基望远镜主要是口径8～10米的反射镜,它们代表了自伽利略将望远镜用于夜空研究400年以来光学望远镜发展的巅峰。其中有建在智利的欧洲空间局的甚大望远镜(由4台8米望远镜构成),位于夏威夷的两台10米凯克望远镜和8.3米昴星望远镜,双子望远镜(两台望远镜分别装在南半球和北半球),以及德克萨斯州麦克唐纳天文台的9米大型拼镶镜面望远镜。     

Additive Maps Preserving Nilpotent Operators or Spectral Radius

Let X be a （real or complex） Banach space with dimension greater than 2 and let B0（X） be the subspace of B（X） spanned by all nilpotent operators on X. We get a complete classification of surjective additive maps Ф on B0（X） which preserve nilpotent operators in both directions. In particular, if X is infinite-dimensional, we prove that Ф has the form either Ф（T） = cATA^-1 or Ф（T） = cAT＇A^-1, where A is an invertible bounded linear or conjugate linear operator, c is a scalar, T＇ denotes the adjoint of T. As an application of these results, we show that every additive surjective map on B（X） preserving spectral radius has a similar form to the above with ｜c｜ = 1.     

NECESSARY CONDITIONS FOR OPTIMAL CONTROLS OF SEMILINEAR ELLIPTIC VARIATIONAL INEQUALITIES INVOLVING STATE CONSTRAINT

This paper deals with maximum principle for some optimal control problem governed by some elliptic variational inequalities. Some state constraints are discussed. The basic techniques used here are based on those in [1] and a new penalty functional defined in this paper.     

Boundedness of Multilinear Operators on Herz Type Spaces： Extreme Cases

In this paper, two classes of closely related multilinear singular and fractional integrals,which include the commutators as special cases, are studied and their boundedness on Herz type spaces is discussed. In fact, it is proved that these operators are actually not bounded in certain extreme cases.     

Local Prediction of Chaotic Time Series Based on Support Vector Machine

Based on phase space delay-coordinate reconstruction of a chaotic dynamics system, we propose a local prediction of chaotic time series using a support vector machine （SVM） to overcome the shortcomings of traditional local prediction methods. The simulation results show that the performance of this proposed predictor for making onestep and multi-step prediction is superior to that of the traditional local linear prediction method and global SVM method. In addition, it is significant that its prediction performance is insensitive to the selection of embedding dimension and the number of nearest neighbours, so the satisfying results can be achieved even if we do not know the optimal embedding dimension and how to select the number of nearest neighbours.