图书馆网站Web页面增长规律研究——基于美国三种类型图书馆网站的典型调查分析

以美国公共、专业和高校三种类型图书馆网站的代表为典型调查对象,利用Alltheweb搜索引擎检索它们每年新出现的网页数量及建立网页数据的时间序列.然后运用统计学中的时间序列分析方法和SPSS软件对数据进行统计分析.得出结论:在图书馆网站的初始发展阶段,网页增长经历三个时期、符合普赖斯科学文献指数定律、增长指数与平均发展速度正相关.图1.表3.参考文献8.     

一类mKdV方程的孤波解

对双曲函数法进行扩展,然后利用一种基于符号计算的代数方法,结合Maple环境中的Epsilon软件包,求解mKdV方程,获得了若干其它方法不曾给出的形式更为丰富的新的显式行波解,其中包括孤波解、三角函数解、双曲函数解和Weierstrass椭圆函数周期解．并用扩展了的双曲函数法求得mKdV方程的新周期波解和孤波解．     

Using diagrams as tools for the solution of non-routine mathematical problems

The Mathematics education community has long recognized the importance of diagrams in the solution of mathematical problems. Particularly, it is stated that diagrams facilitate the solution of mathematical problems because they represent problems’ structure and information (Novick & Hurley, 2001; Diezmann, 2005). Novick and Hurley were the first to introduce three well-defined types of diagrams, that is, network, hierarchy, and matrix, which represent different problematic situations. In the present study, we investigated the effects of these types of diagrams in non-routine mathematical problem solving by contrasting students’ abilities to solve problems with and without the presence of diagrams. Structural equation modeling affirmed the existence of two first-order factors indicating the differential effects of the problems’ representation, i.e., text with diagrams and without diagrams, and a second-order factor representing general non-routine problem solving ability in mathematics. Implicative analysis showed the influence of the presence of diagrams in the problems’ hierarchical ordering. Furthermore, results provided support for other studies (e.g. Diezman & English, 2001) which documented some students’ difficulties to use diagrams efficiently for the solution of problems. We discuss the findings and provide suggestions for the efficient use of diagrams in the problem solving situation.     

Self‐efficacy,school resources,job stressors and burnout among Spanish primary and secondary school teachers: a structural equation approach

This study examines the relationship between school resources, teacher self‐efficacy, potential multi‐level stressors and teacher burnout using structural equation modelling. The causal structure for primary and secondary school teachers was also examined. The sample was composed of 724 primary and secondary Spanish school teachers. The changes occurring in the Spanish teacher role in the last decade were taken into account to select job stressors. The results obtained revealed that external (school support resources) and internal (management classroom self‐efficacy and instructional self‐efficacy) coping resources have a negative and significant effect on job stressors. In turn, job stressors have a positive and significant effect on teachers’ burnout considering it as both a unidimensional and multidimensional construct. Furthermore, the hypothesised structure of burnout dimensions revealed that emotional exhaustion plays a key role in explaining Spanish school teachers’ burnout. Practical implications of these findings are discussed.     

Effects of Exposure to Part-time Faculty on Community College Transfer

Over the past several decades, one of the most significant changes in the delivery of postsecondary education involves the dramatic increase in the use of contingent or part-time faculty. Although the increased use of part-time faculty within higher education makes sense from an administrative point of view, its use does not come without criticism. With community colleges representing a more convenient, affordable, and flexible educational option for a number of students, particularly those from disadvantaged backgrounds, examining how exposure to part-time faculty relates to students’ academic goals represents an important area of inquiry. This study draws from social and human capital frameworks and uses hierarchical generalized linear modeling (HGLM) to examine how exposure to part-time faculty relates to community college students’ likelihood of transferring to a four-year college or university. Findings suggest that students tend to be significantly less likely to transfer as their exposure to part-time faculty increases.     

一类奇异摄动延迟积分微分方程的指数稳定性

奇异摄动延迟微分方程广泛出现于科学与工程应用领域。本文讨论了一类单参数奇异摄动积分微分方程的指数稳定性质,并应用Halanay不等式得到了稳定性成立的判定条件。     

多项式向量场空间的维数与基

本文借助于数域P上的n次多项式的齐次分解,证明了线性空间P[X1,X2,…Xn]m的维数等于Cn＋m^n并给出了该空间的一组基;进而得到R^n上次数不超过m的多项式向量场的全体构成的线性空间V的维数等于n·Cn＋m^n。     

辐射带电粒子在电磁场中的运动方程

带电粒子和电磁场相互作用时,带电粒子激发电磁场的同时电磁场又对粒子有反作用,要求解带电粒子与电磁场系统的动力学问题,必须把两者之间的相互作用同时考虑,才能得出完整的粒子运动方程以及电磁场.在经典电动力学的基础上,讨论了辐射阻尼力影响下非相对论性带电粒子在复合场中的运动,导出了辐射带电粒子的完整地运动方程,模拟了带电粒子对外辐射的电磁能量.     

基于线阵CCD的迈克尔逊干涉仪测量金属丝的弹性模量

对现有迈克尔逊干涉仪予以简单改造,通过在金属丝上持续而均匀加力的变化引起金属丝细微伸长进而带动移动镜移动,从而引起光屏上干涉圆环数目的变化;通过对干涉圆环的自动精确记录就可以实现对金属丝微小伸长量的测量,提出了一种用线阵CCD作为光电传感器件捕捉干涉圆环的光强信号,再将电信号进行模数转换。采取USB接口与微机接口,用C++语言编写程序设计了一种新型的干涉圆环自动计数软件。将这种计数方法与金属丝弹性模量的测量结合起来,可以自动得出金属丝的弹性模量,且提供了一种交互性强的友好图形界面。     

一维无限深势阱的教学思考与应用

本文尝试按照递进的思维主线找到各类一维无限深势阱问题解法的联系与关联,并将最后结果用到一个实际例子中去,得到一个自洽的结果。