奇摄动非线性状态调节器问题的渐近解*

我们将寻求最优控制和奇摄动非线性状态调节器问题的相应轨道.在适当的假设下将有可能去完成当ε→0时一致有效的渐近解.     

多组分聚氨酯大孔吸附树脂的结构及形态结构

经缩聚和加聚反应分步聚合制得聚氨酯大孔吸附树脂,通过红外光谱分析等手段证实大孔树脂的骨架结构与原设计一致,在于态下测得的比表面积为120m²/g,且性能稳定、孔径分布窄、机械强度高。利用DSC、SAXS对其骨架结构进行研究的结果表明:聚氨酯大孔树脂具有微相分离的形态结构,且存在两种分散相。     

由偏微支配的系统的最优控制理论中的奇异摄动方法*

本文介绍了由偏微分方程支配的系统的最优控制理论中有关应用奇异摄动方法时出现的各种问题。考虑了渐近分析来自状态方程。或来自性能指标函数,也考虑了状态方程是定义在摄动域内的情形。     

STUDY OF HALOGEN DOPING IN POLYCRYSTALLINE YBa2Cu3O7-δ

This paper presents systematically the doping effects of halogens in YBa₂Cu₃O_7-δ polycrystalline samples, with a series of concentrations of fluorine, chlorine, bromine or iodine. All samples were prepared by chemical method of citrate pyrolysis, which makes the halogen concentration in the samples more uniform. Samples doped with F have T_c as high as 94.5K, Cl, Br and I dopings also raise T_c to a certain extent. In addition, the influence of halogen doping on critical current density, morphology, constitution and so forth is discussed.     

Pt、Pd蜂窝催化剂高温老化对甲醇氧化的影响

考察了Pt、Pd蜂窝催化剂,分别加或不加助化剂铈和钨,经空气高温焙烧后,各催化剂对甲醇氧化的活性、选择性和动力学网络的变化。发现Pt具有比Pd好的低温活性,然而耐温性却较差,在500和700℃焙烧4小时的催化剂上甲醇氧化生成的主要副产物是中间产物HCOOCH₃,经900和1100℃焙烧4小时后,生成的主要副产物是平行产物HCHO。Pt与Ce的相互作用得到验证,并且发现WO₃;能与童青石蜂窝体中的MgO,CaO在高温下发生相互作用生成MgWO₄和CaWO₄。     

Variational methods for the problems of nonconservative force fields in the micropolar elastodynamics

Based on the properties of the convolution and the convolute commutation, some quasi-variational principles for the problems of nonconservative force field in the micropolar elastodynamics are given and verified in this paper. The theorem given in this paper can be applied to the theories of the nonlocal elastic mediums and the nonlocal micropolar elastic mediums.     

Solution of bending of cantilever rectangular plates under uniform surface-load by the method of two-direction trigonometric series

The bending of a cantilever rectangular plate is a very complicated problem in thetheory of plates.For a long time,there have been only approximate solutions for thisproblem by energy methods and numerical methods.since 1979,Prof.F.V.Chang of Tsing Hua University obtained,by the method ofsuperposition,a series of analytic solutions for cantilever rectangular plates under uniformload and concentrated load.In this paper,the two-direction trigonometric series is used to obtain the solution forthe bending of cantilever rectangular plates under uniform load.The obtained results arecompared with the results by the method of superposition.The comparison shows that theresults of these two methods are in good agreement,hence they are mutually confirmed to becorrect.     

三氯化铕四吡啶的晶体结构

稀土有机化合物的研究是当前十分活跃的一个领域。我们首先用X射线单晶衍射的方法,测定了EuCl~3.4Py的晶体结构,揭示了这类配合物的结构特征。     

烃在HZSM-5沸石上的程序升温脱附

本文研究了烃在HZSM-5沸石上的程序升温脱附(TPD).正己烷、环己烷和苯的TPD谱只有一个陡峰,对和间二甲苯的TPD谱均呈现出双峰.实验测得脱附活化能的次序为:正己烷>对二甲苯>苯>环己烷.水汽处理对正己烷的TPD影响不大;但对二甲苯的TPD影响较大.随着吸附量的增大,二甲苯逐渐占据孔道深处的强活性位置.     

自适应滤波器的修正的时域正交性算法及其应用

本文绘出了一个自适应滤波器的修正的时域正交性算法.计算机模拟结果表明,该算法有两个特性:一、相同的收敛因子c可以在比较宽范围的输入信号信噪比内使用。二、应用这种方法的噪声消除器的一个实用特性是,对于相同的期待信号,输入的参考信号的功率变化,不影响收敛因子c值的选择,这就使这种噪声消除器的应用更灵活。文中给出了这种算法用于谱估值时的特性,并与LMS算法进行了比较。