Testing results analysis of contact materials＇ electrical contact performance

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.     

Teacher educators as curriculum developers: exploration of a professional role

Teacher educators arguably fulfil several roles in their professional context: they can be seen as role models or teachers of teachers, and have additionally been characterised as researchers, mentors, gatekeepers, brokers, and curriculum developers. To address a perceived gap in the literature on the latter role, a quantitative and qualitative exploratory study into educators’ own perceptions of their role as curriculum developers was conducted at a large teacher education department in the Netherlands. Seventy-five educators completed a digital questionnaire. Their responses reveal that the participants generally consider themselves to be curriculum developers, are aware of the responsibilities this professional role entails, and can pinpoint concrete practices in which the role becomes visible. The findings furthermore suggest that educators have been prepared for and develop professionally in this role in a variety of ways, mostly through informal learning with their colleagues at the workplace. Based on these findings, recommendations are made to inform educational practice, policy, and research.     

改性PbTiO3压电陶瓷的研究与发展

本文简要地述了PbTiO3压电陶瓷的掺杂改性研究现状,着重于PbTiO3压电陶瓷的掺杂改性的实用意义,介绍了一些具有典型优良压电特性的掺杂配方及其陶瓷材料的机电性能.     

国内教师学科教学知识（PCK）研究：现状审视与未来展望——基于2005-2019年CNKI文献计量分析

国内关于教师学科教学知识(PCK)的研究自2005年起便倍受关注,经历了萌芽、飞速发展和滞缓瓶颈三个阶段。通过对教师PCK相关研究文献进行计量可视化分析发现,研究主题聚焦于PCK理论分析框架的内涵阐释和对各学科教师PCK的迁移与专业化发展的推动,研究群体的学科、学段、教学职业阶段分布较为广泛多样等,但其中也存在本土化引介进程中与教师教学实践脱节、学科分布和研究地区分布不均衡、研究方法较为单一、评价体系不够完善等问题。关注教师PCK与教学实践的交互作用、发挥优势地区、研究机构和学科的引领与支援作用以及强化PCK信息技术时代体系更新与完善是新时期PCK研究深化与拓展的关键所在。     

综合性和创新性实验的设计与实践——Biginelli反应

在室温离子液体作催化剂的条件下,利用苯甲醛、尿素和乙酰乙酸乙酯3组分缩合反应,一锅煮的方法制备3,4-二氢嘧啶-2-酮衍生物。本实验是学生基础实验延伸,并且在学生实验结果统计分析的基础上,分析了本科学生综合创新能力。     

The Development and Psychometric Properties of the Teacher Social Stress Scale-Student Related (TSS-Sr)

Teacher burnout is a growing phenomenon that may dramatically reduce the quality of life of both teachers and students. Many studies have conceptualized teaching as a high-contact profession and, focusing on the emotional exhaustion dimension of burnout, they have highlighted the relation with students as a key dimension of teachers’ stress. This paper presents an original instrument (TSS-Sr) to measure teachers’ stress related to the interaction with their pupils. It provides the psychometric characteristic of this scale. Results support a model of measurement of teacher social stress based on four dimensions: verbal aggression, dislike students, awkward reactions, demanding requests. Implications about the use and the applications of this instrument are discussed.     

Krankenanstalten; Arbeits- und Sozialrecht; Gesetzgebungskompetenz

Der Landesgesetzgeber vermag seine Gesetzgebungskompetenz betreffend die angefochtene Bestimmung arbeits- und dienstrechtlichen Inhalts angesichts dieser Komplexit?t weder auf den Kompetenztatbestand des Art 12 Abs 1 Z 1 B-VG "Heil- und Pflegeanstalten", noch auf die Kompetenznorm des Art 21 Abs 1 B-VG zu stützen.     

基于CATIA数字编辑器实现逆向工程的数据处理

介绍了基于CATIA数字编辑器的逆向工程数据处理方法.以产品为例,对工业造型领域中从实体零件三维扫描测量输出点位数据,利用软件对数据处理过滤,最后建立曲面曲线以供CAD软件调用建模等一整套方法进行了探讨.     

TiO2前驱物对水热合成超细BaTiO3产物的影响

TiO_2前驱物在整个水热合成超细BaTiO_3的反应过程中起着重要的作用。通过对不同晶粒尺寸、不同晶型结构的TiO_2作为水热合成超细BaTiO_3的反应前驱物进行实验研究,发现了在其它反应条件,如反应温度、时间、PH值、Ba/Ti摩尔比等,完全相同的情况下,BaTiO_3产物的晶粒尺寸和四方度有明显差别。     

Professional controversies between teachers about their summative assessment practices: a tool for building assessment capacity

Abstract

This article describes two collaborative research projects whose common goal was to explore the potential role of professional controversies in building teachers’ summative assessment capacity. In the first project, upper primary teachers were encouraged to compare their practices through a form of social moderation, without prior instructor input or theoretical preparation. In the second project, lower secondary school teachers were encouraged to compare their summative assessment practices with reference to a theoretical model of curriculum alignment, under the guidance of an instructor. The findings support the potentially constructive role of professional controversies in supporting teachers’ professional development for summative assessment. They highlight the status of references called upon in discussion of controversies, and their contribution to the construction of the subjects under discussion.