变换法在解微分方程中的应用

变量代换法是解常微分方程的一种辅助方法，它能使问题简化．本文通过联系实例给出了变换在求解微分方程中的具体应用。     

一类四阶非线性常微分方程的两点边值问题解的存在性与唯一性

本文利用Hammerstein型积分算子和上下解方法,研究了一类四阶非线性常微分方程的两点边值问题     

Monte carlo estimates of the distributions of the random polygons of the voronoi tessellation with respect to a poisson process

A large-scale study, in which two million random Voronoi polygons (with respect to a homogeneous Poisson point process) were generated and mensurated, is described. The polygon characteristics recorded are number of sides (or vertices), perimeter, area and interior angles. A feature is the efficient “quantile” method of replicating Poisson-type random structures, which it is hoped may find useful application elsewhere.     

Differential customer racial attitudes toward scandal and patriotism: The Mitchell Report,the Olympics,race, and baseball memorabilia

This paper investigates differential customer racial reaction to negative and positive publicity related to professional athletes. In terms of negative publicity, it analyzes the effect of mention in the Mitchell Report on the price of baseball cards. In regards to positive publicity, it considers the impact of having been identified as a member of the United States Olympic or national team. After controlling for player productivity with performance statistics, the effects of being mentioned in the Mitchell Report are isolated within regression analysis to draw conclusions concerning customer racial attitudes toward the steroids scandal. Similar analysis is conducted to see the impact of being seen as a baseball representative of the United States. Regression results are consistent with the conclusion that negative publicity devalues the cards of nonWhite players but not of White players. Positive publicity, however, increases the value of a player's card regardless of ethnicity.     

国外教师差别行为的研究现状与展望

近年来国外对教师差别行为的研究取得了较大的成就。文章从差别行为的研究范式、结构与测量及研究内容三个方面对该领域的现状进行描述,并在此基础上对该现象的未来发展趋势进行展望,以期人们能更好地把握该领域的发展轮廓,推动该领域的研究与发展。     

场域关联、差序嵌入与信任结构的再生产——基于华北一所科技小院的经验研究

文章试图通过分析外源型农技推广组织与农村社区长达10年互动的社会过程来呈现非先赋性信任再生产的逻辑。分析发现,外源型农技推广组织实现由外而内并不是从“外人”变为“自己人”的线性嵌入,而是在“深嵌则依附”与“浅嵌则独立”之间寻找契洽共存的身份认同与行动空间的过程。虽然外源组织囿于乡土社会中内外有别、关系本位的特性,但是其反以“关系”为策略,基于“利益”与“情感”两个维度在场域关联的空间中差序性嵌入,通过高频的人情交往和利益交换在核心家族和区位格局的次级群体上建立自身的核心圈和亲近层,借助增产增量建立组织声誉来扩散村庄整体的互惠网络,将小院院所开放成半公共空间以生产着“生-熟”的信任格局,采取差序分利和模糊雇工来平衡环境依赖和组织独立,以实现从客人到帮手、从帮手到伙伴的身份转变,最终建立组织的合法性身份与行动的合情性空间,在“能否行动”的基础上推动“行动顺畅”成为可能。这种“伙伴”身份的建立过程也再生产着具有伦理性质的信任关系,此类非先赋性的多主体、多维度、层层推进的信任结构,是外源组织嵌入乡土但是不囿于乡土的切实选择。基于此,文章认为,外源组织由外而内的实现不只是一种嵌入过程,更是一种总体性信任结构的生产过程。     

‘Colour-evasiveness’ and racism without race: the disablement of asylum-seeking children at the edge of fortress Europe

This article explores discriminatory discourses articulated by Italian professionals operating in educational, health and social services for refugees in Rome, in relation to the educational and social inclusion of unaccompanied asylum-seeking and refugee children. It locates such narratives within the historical ‘concealment and invisibilisation of race and racism’ that have characterised Italy particularly since the end of the Second World War, while showing how they legitimate contemporary processes of disablement and over-representation of forced migrant children in the category of Special Educational Needs. A theoretical framework influenced by Dis/ability Critical Race Studies, Italian postcolonial studies, and Judith Butler’s notions of subjectivation and performative politics is used to discuss how a ‘colour-evasive’ racial ideology has seeped into various institutions in Italian society, and importantly into education policies and practices.     

Investigating the differential mobility experiences of Chinese cross-border students

Recent migration studies have adopted the lens of mobility to examine the stratifying effects of border policies, but few investigate the differential mobility of migrant families and children. This paper aims to contribute to the migration literature by considering the interplay between border policies, family configurations, and differential mobility. We apply the lens of differential mobility to the experiences of Chinese cross-border pupils – young child migrants with Hong Kong permanent residency who reside in Shenzhen, China, and cross the border to attend school. We begin by describing shifts in Hong Kong’s border and immigration policies since 1997, which have created a typology of families differentiated by mixed status, citizenship rights, and mobility. We then turn to four case studies of students with unequal border-crossing experiences to elucidate how border control constrains or promotes family mobility and perpetuates inequalities.     

AC/DC电路故障检测仪设计

本文介绍了一种可在被检测设备电路不带电状态下工作的AC/DC电路故障检测仪,并对其电路工作原理、测试方法进行了较详细的分析.     

On cumulative entropies

In analogy with the cumulative residual entropy recently proposed by Wang et al. [2003a. A new and robust information theoretic measure and its application to image alignment. In: Information Processing in Medical Imaging. Lecture Notes in Computer Science, vol. 2732, Springer, Heidelberg, pp. 388–400; 2003b. Cumulative residual entropy, a new measure of information and its application to image alignment. In: Proceedings on the Ninth IEEE International Conference on Computer Vision (ICCV’03), vol. 1, IEEE Computer Society Press, Silver Spring, MD, pp. 548–553], we introduce and study the cumulative entropy, which is a new measure of information alternative to the classical differential entropy. We show that the cumulative entropy of a random lifetime X can be expressed as the expectation of its mean inactivity time evaluated at X. Hence, our measure is particularly suitable to describe the information in problems related to ageing properties of reliability theory based on the past and on the inactivity times. Our results include various bounds to the cumulative entropy, its connection to the proportional reversed hazards model, and the study of its dynamic version that is shown to be increasing if the mean inactivity time is increasing. The empirical cumulative entropy is finally proposed to estimate the new information measure.