三相异步电动机Y-△降压起动的PLC控制线路设计

针对三相交流异步电动机在额定电压下直接起动时存在的弊端,通过PLC中的定时器及互锁、连锁等保护手段对电动机Y-△降压起动加以控制,从而避免操作不当或误操作而引起事故。这里主要讨论改进后的继电器接触控制电气原理图,对应的I/O配置接线图,PLC梯形图,部分程序,并对改进后的原理进行分析,从而得出采用PLC控制的Y-△降压起动的优越性。     

浅谈高校交往空间设计

文章首先对我国高校交往空间的基本状况做了简要的介绍,探讨了从空间形态的整体性、多样性、可生长性等方面塑造高等学校交往空间的可能性。     

Bringing together acculturation theory and intergroup contact theory: Predictors of Flemings’ expectations of Turks’ acculturation behavior

The present paper explores Flemish majority members’ expectations concerning the acculturation of Turkish minorities. We studied two kinds of antecedents: majority members’ perceptions of Turkish minorities’ acculturation behavior and their experiences of intergroup contact. The possible mediating role of outgroup affect was also investigated. 247 Flemish high school students completed a survey. Data were analyzed using path analyses. Results show that positive contact experiences and perceiving that Turkish immigrants make efforts to engage in contact with the host group and/or to adopt the host culture are associated with less negative affective reactions towards Turkish migrants. Perceiving that Turkish immigrants maintain their heritage culture is associated with more negative affective reactions. Our results further revealed that increased negative affective reactions are associated with less support for culture maintenance and for contact with the host group but with a higher demand for host culture adoption. The present results also show that expectations of contact engagement and expectations of host culture adoption cannot be considered as equivalent. This implies that results from studies using Berry's conceptualization of acculturation expectations (Berry, 2001) and results from studies using Bourhis’ conceptualization of acculturation expectations (Bourhis, Moïse, Perreault, & Senécal, 1997) are not directly comparable. Our data also clearly disconfirm the orthogonal structure of the fourfold acculturation model for majority members’ acculturation expectations, suggesting that relying on the specific dimensions defining acculturation expectations may constitute a more valid approach to understand ongoing acculturation processes.     

高速铁路运营过程中的关键问题：轮轨磨耗等

随着高速铁路运营里程和列车运营速度的不断增长,出现了一些和列车轨道耦合大系统密切相关的关键科学和技术问题。这些问题不仅影响到列车的运行品质,甚至威胁到安全运行,是当前高速铁路运用和发展中急需解决的问题。本文系统描述了高速铁路在运营过程中所出现的一些关键科学和技术问题,并述评了全世界有关这些问题的研究进展、现状和不足之处,提出了今后有利于认识和解决这些问题的发展方向。在长期高速运营的铁路大系统环境中,这些问题的形成的机理、发生、发展过程和预防措施的研究,需要从列车／轨道耦合大系统运营环境（速度、路况、气候和运用维修）、系统的自身参数匹配、材料选用和运营成本等全面系统考虑,并从理论、技术、工艺、监控和维修等方面解决。     

一类拟线性薛定谔方程的正解

考虑一类拟线性薛定谔方程的正解,由于该类方程所对应泛函不能定义在常用空间H1（RN）上并且嵌入是非紧的,这也导致了很难直接求解.因此利用变量变换在H1（RN）的径向空间上考虑方程的解,从而可以利用山路引理和极值原理证明所研究方程存在正解.     

母语迁移对二语习得的影响——以语音迁移为例

语言迁移是外语学习中的一种普遍现象,在二语习得理论研究中占有重要的位置,也是第二语言习得整个过程中的一个重要的因素,它分为正迁移和负迁移。正迁移能促进外语学习,而负迁移增加了外语学习的难度。分析母语迁移对外语学习具有深远的意义。     

Exploring the Relations between In-service Training,Prior Contacts and Teachers’ Attitudes towards Persons with Intellectual Disability

This study investigates the relations between teachers’ attitudes towards persons with intellectual disability (ID), in-service training on ID, and prior contacts with persons with ID. A sample of Canadian elementary school teachers (N?=?118) completed the Attitudes Toward Intellectual Disability Questionnaire, which measures cognitive, affective and behavioural components of attitudes towards persons with ID. Correlational and multivariate regression analyses were performed. Frequent contacts with persons with ID and experience of including a child with ID increased the likelihood of reporting prior positive contacts with persons with ID. In turn, this was associated with less discomfort towards persons with ID and more willingness towards interactions. In-service training on ID was related to better knowledge of rights and capabilities of persons with ID. Experience of including a child with ID in general education classrooms increased the likelihood to report feeling competent in teaching children with ID, which predicted more willingness to include children with ID.     

The Significance of Positive Chinese Transfer in English Learning for Art Students and Its Pedagogical Implications

The phenomenon of language transfer has always been a central issue in the field of second language acquisition. Meanwhile,the role and status of mother tongue in the process of foreign language learning has been a controversial topic for both linguists and scholars as well. Normally divided into positive transfer and negative transfer, language transfer can be widely observed in the language teaching process during which the negative sides hinder the learning of new language while the positive sides facilitate the acquisition of new knowledge. In the specific context of China, language transfer mainly focuses on the transfer of learners' mother tongue-Chinese in English learning process. In this paper, the author mainly discusses the positive transfer of Chinese to those art students whose English competence is relatively poor taking its aim at figuring out a proper strategy for English teaching.     

职业教育中学生的能力培养研究

当代大学生的能力包括认知能力、操作能力和社交能力三种,我们通过分析教学过程中知识、技能和能力之间的关系,提出了通过知识传授培养学生认知能力和社交能力、通过技能训练培养学生实践操作能力的方法和途径,提高了学生适应各种不同工作岗位的综合素质,增强了学生从容面对新岗位、新问题挑战的自信。     

斜拉桥主梁施工底板局部承压安全验算方法

混凝土斜拉桥采用挂篮施工主梁时,挂篮底部行走轮对主梁底板产生巨大的竖向反力.混凝土底板、肋板可能在此反力作用下发生局部承压开裂破坏,需进行安全验算.行走轮与底板的接触区域是未知的,混凝土的受力变形均由接触区域决定.为寻求简单适用的计算方法,采用弹性接触Hertz理论,求解行走轮与混凝土板接触区域大小及应力分布,在此基础上应用规范推荐公式进行底板及肋板的抗裂安全验算.算例表明,该方法是可行的,可以简便地进行主梁底板的局部承压安全验算.