Error estimate of eigenvalues of perturbed second-order discrete Sturm–Liouville problems

This paper is concerned with eigenvalues of perturbed second-order vector discrete Sturm–Liouville problems. By some variational properties of eigenvalues of discrete Sturm–Liouville problems, error estimates of eigenvalues of perturbed problems, sufficiently close to a given Sturm–Liouville problem, are given under a certain non-singularity condition. Perturbations of the coefficient functions of the difference equation, the weight function, and the coefficients of the boundary condition are all considered. This, together with higher-dimension involved, results in a certain complexity of the problem and difficulty of study. As a direct consequence, continuous dependence of eigenvalues on problems is obtained under the non-singularity condition. In addition, an example is presented to illustrate the necessity of the non-singularity condition.     

A novel pentaazadentate bismacrocycle cadmium complex

A novel pentaazadentate bismacrocycle was synthesized through an improved procedure of 1:1 Schiff base condensation of diformyltripyrrane with 3,4,3′,4′‐tetraamino‐biphenyl hydrochloride using Pb²⁺ as template ion, in which the condensed byproduct water was removed efficiently to make the yield over 90%. Then the bismacrocycle legend reacted with cadmium chloride to yield the title metal complex with molecular weight being 1200.4 by TOF MS and the λ_max being 766 nm.     

Approximate colored range and point enclosure queries

In this paper, we formulate two classes of problems, the colored range query problems and the colored point enclosure query problems to model multi-dimensional range and point enclosure queries in the presence of categorical information. Many of these problems are difficult to solve using traditional data structural techniques. Based on a new framework of combining sketching techniques and traditional data structures, we obtain two sets of results in solving the problems approximately and efficiently. In addition, the framework can be employed to attack other related problems by finding the appropriate summary structures.     

分光路二维剪切干涉强激光腔镜变形检测系统

介绍一种分光路二维剪切干涉光电检测系统。该系统实现了两正交方向(二维)同时进行检测与计算机自动化数据处理;采用了一系列消噪声措施和两图像相减等技术,使得波前重构中能较好地采用简单的数值积分方法;并得到了在士10μm的测量范围内,方差不超过0. 257μm和0. 05μm的灵敏度。利用该系统成功地对强激光腔镜变形过程实现了动态检测。     

Windows95环境中转速测量和直流电机转速控制方法

介绍在Windows95环境中用Visual Basic5.0编写转速测量和直流电机转速控制方法的过程。     

Banach空间中渐近非扩张映象具误差的强收敛定理

设E是一实的Banach空间,其范数是一致Gteaux可微的;D是E的一非空闭凸子集,设T:D→D是具有序列{k_n}[1,∞),lim_(n→∞) k_n=1的渐近非扩张映象.本文证明了,在一定条件下,由(1.3)和(1.5)式定义的具误差的迭代序列{x_n}强收敛于T的不动点.本文结果也推广和改进了最近一些人的最新结果.     

基于磁开关的全固态、高功率、长脉冲发生器的初步研究

大多数电容储能型脉冲功率装置的共同特点是采用了气体开关,由于气体绝缘恢复的限制和电极的烧蚀,使得其重复频率都不太高,而且寿命有限.而目前广泛研究的磁脉冲压缩技术在脉冲功率系统的长寿命、高平均功率和高重复频率运行方面具有很大的应用前景.通过对BOOST电路、LC谐振电路和磁脉冲压缩电路详细的理论分析和计算机模拟,设计了由B00ST电路,C谐振电路,脉冲变压器,磁压缩系统,负载五大部分组成的脉冲发生器电路系统模型,使用Pspice软件对系统进行了模拟、优化,得到了电压幅值为55kV,脉宽为500ns的输出脉冲.     

Tadpole‐shaped amphiphilic copolymers prepared via RAFT polymerization and click reaction

The tadpole‐shaped amphiphilic copolymers with cyclic polystyrene as the head and a linear poly(N‐isopropylacrylamide) as the tail have been successfully synthesized by combination of reversible addition‐fragmentation chain transfer (RAFT) polymerization and “click” reaction. The synthesis involves two main steps: (1) preparation of a linear acetylene‐terminated PNIPAAM‐b‐PS with a side azido group anchored at the junction between two blocks; (2) intramolecular cyclization reaction to produce the cyclic PS block using “click” chemistry under high dilution. The structures, molecular weights, and molecular weight distributions of the resulted intermediates and the target polymers were characterized by their ¹H NMR, FTIR, and gel permeation chromatography. The difference of surface property between tadpole‐shaped polymer and its linear precursor was observed, and the water contact angles on the former surface are larger than that of the latter surface. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2390–2401, 2008     

An X‐shaped π‐conjugated polymer comprising of fluorene units and anthracene units with high efficiency. Synthesis and optical and electrochemical properties

A new X‐shaped π‐conjugated monomer comprising of fluorene units and anthracene units was synthesized, and it was used to fabricate the new X‐shaped π‐conjugated polymers and investigate the properties of the new polymers. Using different molar ratios between such monomer and a fluorene monomer gave three polymers that showed higher absolute PL quantum yields than the linear polyfluorene (PF) in the solid state. After thermal annealing at 200 °C for 4 h, the linear PF showed an additional bathochromic emission at about 550 nm, whereas such red‐shifted emission was fully eliminated for the X‐shaped polymers. The electroluminescent devices based on the X‐shaped polymers with a configuration of ITO/PEDOT:PSS/polymer/LiF/Ca/Al displayed blue emission with low turn‐on voltage and high brightness. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5616–5625, 2008