Testing results analysis of contact materials＇ electrical contact performance     

WANG Jing-qin WANG Hai-tao WEN Ming ZHU Yan-cai 《浙江大学学报(A卷英文版)》2007,8(3):459-463

Because of the different ways in which contact materials work, the basic requirements for silver metal oxide contact materials are different. They are anti-welded and anti-erosion when closed, anti-erosion when broken, and arc easily moved and have smaller contact resistance. In this paper, La2O3 is used as a stable oxide in contact material to replace CdO. A new type of Ag/SnO2-La2O3-Bi2O3 contact material is first obtained through using powder metallurgical method. Then electrical contact material parameter tester is used to test the electrical contact performance of the contact material. Through experiments, the arcing voltage and current curves, arcing energy curves, fusion power curves while broken and contact resistance while closed were obtained. Analysis of the results showed that the addition of La2O3 makes the contact material have the following advantages： smaller electrical wear, smaller arc energy, smaller contact resistance and arc is more easily extinguished.  相似文献   

试析幽默的语用合作原则   总被引：6，自引：0，他引：6  

刘乃实 《清华大学教育研究》2002,(Z1)

本文从语用学的合作原则角度对幽默作了探讨。首先讨论了幽默与合作原则的关系。一方面幽默是成功的交际形式 ,另一方面它又违反了约束成功交际的格赖斯合作原则的某一 (几 )项准则。进而介绍了两种比较有代表性的能够解释这一矛盾的理论。一个是日本语言学家山口的“提及理论” ,另一个是拉斯金的真诚交际与非真诚交际模式的理论以及一套适合于笑话的合作原则。经过分析比较 ,笔者认为后者更具有普遍意义和实用性 ,但仍需进一步完善。  相似文献   

圆钢矫直机轧辊曲面的设计     

魏伟  孙爽 《天津工程师范学院学报》2001,11(3):17-19

以轧辊曲面为研究对象,分别运用图解法和解析法求解轧辊曲面的接触线和曲面轮廓线,并可用计算机计算出结果或输出图形,以满足实际生产需要.  相似文献   

Gardnerella vaginalis infection and sexual contact in female children     

David L. Ingram  Susanne T. White  Pauline R. Lyna  Kimberly F. Crews  J.E. Schmid  V.Denise Everett  G.G. Koch 《Child abuse & neglect》1992,16(6):847-853

Gardnerella vaginalis (GV) infection has been reported as being acquired via sexual contact in adults and as an indicator of sexual contact in female children (DeJong, 1985). The purpose of this study was to determine if GV infection was more commonly found in 191 female children who gave a history of sexual contact and/or were infected with Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT) (Group 1), compared with 144 female children evaluated for possible sexual abuse and found to have no such history or infection with GC or CT (Group 2), or 31 female children (friends of the authors) without such a history or GC or CT infection (Group 3). Vaginal GV was found in 5.3% of Group 1, 4.9% of Group 2 and 6.4% of Group 3 (p > .05). Also, vaginal GV infection was not related to the type of sexual contact or race, but did increase with age in white female children. Because vaginal GV infection is not more commonly found in children with a history of sexual contact than those without such a history, the finding of GV in a vaginal culture in an individual case would not be a reliable marker of sexual contact. Routine culturing for GV is not recommended as part of a sexual abuse workup.  相似文献   

四元数空间形式中混合型全拟脐QR-子流形     

赵培标 《周口师范学院学报》2005,22(5):1-7

考查四元数空间形式中混合型全拟脐QR-子流形并研究了四元数空间形式中具有某种条件下的混合型伪脐QR-子流形.进而研究了四元数K(a)ehler流形的QR-子流形,给出了一些有趣的结果.  相似文献   

Integrating Northern Ireland: Cross‐group friendships in integrated and mixed schools          下载免费PDF全文

Danielle Blaylock  Joanne Hughes  Ralf Wölfer  Caitlin Donnelly 《British Educational Research Journal》2018,44(4):643-662

While Northern Ireland strives to build a shared society, the current reality is that everyday experiences are still shaped by division along ethno‐religious lines. This is particularly pronounced in the education system, where more than 92% of pupils attend separate schools. Within the predominantly separate education system, however, exists a small collection of schools which cater to a more heterogeneous pupil body and offer the opportunity for young people from both communities to meet and interact, and potentially develop cross‐group friendships. The present study compares the network‐based cross‐group friendships within two such school types; an integrated and a separate post‐primary school. These schools boast a distinct ethos yet they similarly enrol students from Catholic and Protestant backgrounds. Findings reveal that both schools show a high level of interconnection between pupils; however, the integrated school, with an ethos that openly supports social cohesion, shows a greater tendency towards cross‐group interactions and best friendships than those found within the separate school. In line with contact theory, these findings suggest that it may not be enough to simply create opportunities for intergroup contact but that optimal conditions, such as institutional support, may be a prerequisite for positive relationships to flourish. Implications for educational policies designed to promote greater cross‐community contact are discussed.  相似文献   

社会交往的精神生产力意义     

宋文献 《河北北方学院学报(社会科学版)》2001,(2)

长期以来,学术界往往把人与人之间的社会交往仅仅归之于生产关系,而很少有人重视其生产力功能。实际上,交往作为一种社会实践活动不论从物质层面还是从精神层面上说都具有生产力功能。文章运用马克思主义的社会交往理论,主要从精神交往这个层面上就社会交往在语言传播、文明成果延续共享、促进人类社会发展等方面论述了社会交往的精神生产力功能,并从若干方面加以具体展开;进而突出了现代社会交往所具有的空前重要的生产力意义。  相似文献   

青海多元文化交融下的语言接触现象     

马梦玲 《青海师范大学学报(哲学社会科学版)》2007,(6):120-122

青海地区多民族聚居，族群的互动促进了语言的接触和交融，使这一地区的各种语言呈现出不同于本来系属语言的特点。本文从青海境内各语言在语音、词汇、语法方面的接触入手，分析论述了青海地区多元文化交融下语言接触后产生的复杂现象。  相似文献   

对数学课程中有关数学文化的思考   总被引：7，自引：1，他引：7  

傅赢芳  张维忠 《数学教育学报》2005,14(3):24-26

数学文化呈现的是开放、多元和动态的数学内部及其与外部的联系.数学文化价值体现在如下4个方面:数学自身价值、科学价值、社会价值与精神价值.基于这样的数学文化观念,有关数学文化课程的设置就应充分重视与学生的文化背景及数学现实的联系,注重数学与其它学科的联系,注重数学内部知识结构之间的联系.  相似文献   

企业多元化战略中的技术转型——新日铁与首钢"造芯"案例研究     

周程  刘渤 《科学学与科学技术管理》2007,28(7):126-133

企业在推进多元化战略、实施技术转型时,存在很多风险。以新日铁和首钢涉足半导体事业为案例,从技术选择、技术学习、文化锁定三个视角探讨了传统企业转换技术轨道的创新管理问题,对钢铁企业“造芯”均遭挫折一事进行了解释。  相似文献