二次方三项式线性齐次微分方程的解法

通过把线性齐次微分方程x2y(n) 2nxy(n-1) n(n-1)y(n-2)=0化为可逐次积分的线性微分方程,找出了它的通解形式,给出了严格的证明,并将其推广,得到x2y(n) (x2 2nx)y(n-1) [2(n-1)x n(n-1)]y(n-2) (n-1)(n-2)y(n-3)=0的通解.     

一类具有分布时滞高阶微分方程的周期解

利用Mawhin重合度理论,研究了一类具有分布时滞的高阶P—Laplacian中立型微分方程,获得了其周期解存在性的一些新结果．     

Changes in the Multi‐Level Effects of Socio‐Economic Status on Reading Achievement in Sweden in 1991 and 2001

This study examines the changes in educational inequality at the school‐ and individual‐levels in 1991 and 2001. Comparisons are made between the IEA Reading Literacy Study 1991 and the so called 10‐Year Trend Study in PIRLS 2001. The between‐school differences in reading achievement variance and the size of the relationship between SES and reading achievement at school‐level are the two main focuses. Applying a two‐level structural equation modeling technique, it was found that the between‐school differences in reading achievement were greater in RLS 2001 than in RLS 1991, and the school SES effect has been strengthened over time. These changes indicate that educational inequality in Sweden has increased over time. Some possible explanations to these changes are discussed with reference to school reforms and demographic changes.     

The Index of Forecasting Efficiency,for the Case of a “True” Criterion

A variety of personal characteristics have been shown to be influential in teacher-student relationships. The sex of the child as well as the appropriateness of his behavior were the factors evaluated in this study. An analysis of the results indicated that sex-inappropriate behavior was viewed less favorably than sex-appropriate behavior. A discussion of the results was presented with regard to support for previous studies and implications for future research.     

非线性2m阶微分方程边值问题解的存在性和多重性

利用强单调映象原理和临界点理论讨论2m阶微分方程边值问题{（-1）^m·u^（2m）（t）=f（t,u（t））,t∈[0.1] u^（2i）（0）=u^（2i）（1）=0 （i=0,1…,m-1）,其中f：[0,1]xR^1→R^1连续,得到其解的存在性和多重性．     

高校课堂教学质量结构方程模型构建与应用——教师评价的视角

将结构方程模型方法用于高校课堂教学质量研究,可以借助观测模型和结构模型来探索潜变量及其相互间的因果关系。基于教师评价视角,对某高等学校课堂教学质量进行调查,对构成课堂教学质量及其因果变量的相互关系进行分析和模型的路径设计,构建了高校课堂教学质量模型,并借助LISREL8.7软件进行了分析,证实模型有较好的拟合度。     

二阶中立型差分方程解的振动性(Ⅱ)

该文对某类二阶非线性中立型差分方程解的振动性进行了讨论,改变了[8]中原有方程的条件,因而完善了此类二阶中立型差分方程解的振动性结果。     

行延拓矩阵的矩阵方程组的最佳逼近解

主要讨论行延拓矩阵的线性约束矩阵方程组的最佳逼近;介绍了延拓矩阵的概念;利用矩阵奇异值分解得到了行延拓矩阵的线性约束矩阵方程组有解的充要条件、通解表达式;最后讨论了相应问题的最佳逼近解的表达式。     

绿色供应链管理视角下港口绿色绩效及竞争力研究——基于沿海港口的问卷数据

伴随港口竞争的加剧,港口的可持续发展越来越受到重视。从全球绿色供应链管理的视角出发,选取沿海三大港口群的中高层管理者为调查对象,运用两阶段的结构方程模型对当前港口供应链管理过程中港口的绿色绩效相关关系进行验证。结果表明:港口的外部绿色合作和内部绿色实践不仅对于港口绿色绩效存在明显的正反馈,还对提升港口竞争力有正向反馈;绿色政策法规的制定与实施对于港口外部绿色合作与内部绿色实践具有正反馈。并基于此给出我国港口在绿色实践过程中提升绿色绩效的相应启示。     

Lyapunov-based design of locally collocated controllers for semi-linear parabolic PDE systems

The design problem of collocated feedback controllers is addressed in this paper for a class of semi-linear distributed parameter systems described by parabolic partial differential equation (PDE), where a finite number of local actuators and sensors are intermittently distributed in space. A Lyapunov direct method for the exponential stability analysis of the resulting closed-loop system is first presented for the system, in which the first mean value theorem for integration and the Wirtinger's inequality are employed. The corresponding stabilization condition is then derived through the analysis result. Finally, the proposed design method is implemented on the feedback control of a fisher equation and its effectiveness is evaluated through simulation results.