项日教学法在汽车零部件识图课程中的应用

在高职汽车检测与维修技术专业汽车零部件识图课程中采用项目教学法是一种全新的尝试。在分析项目教学法的特点和意义基础上,结合汽车零部件识图课程教学特点,通过项目选设、项目教学设计、项目实施、项目考核与评价、拓展训练等阶段,重点阐述了项目教学法在汽车零部件识图课程中的具体应用。进而指出了在项目教学法运用中应注意的问题。     

课程内涵之探讨

我们需要对课程的内涵做严密的探讨,这基于如下背景:理论探究的混乱;新课程改革实践的困惑;课程与教学之关系的难于把握;教育学科体系有序化的任务。探讨课程概念的内涵,在逻辑思路上要依次明确内涵探讨的基本任务,把握这个概念所指对象的基本定位,从基本属性、结构属性、生成属性三个层次上做完整的分析,基本属性即为定义,结构属性即为课程要素及其关系,生成属性即为课程构建的三个层次。需要把握课程的相对边界。     

浅谈金属构件失效分析方法

结合实例介绍了金属构件失效分析中较常用的断口形貌分析、扫描电镜分析、金相组织分析、化学成分分析及人工模拟断口分析等方法.在查找产品的失效原因时,要灵活运用这些方法.     

多面体链环的分支数

多面体链环是由多个相互镶嵌成的具有多面体形状的一种拓扑几何结构。我们在3-正则多面体上构筑了更多类的多面体链环。并且计算了3-正则多面体链环的分支数。     

The era of incremental change in the technology innovation life cycle: An analysis of the automotive emission control industry

According to the life cycle model of technological evolution, after the emergence of a dominant design, technological product industries undergo an “era of incremental change.” This era of incremental change is not well understood in the existing literature. Although the period is typically characterized in terms of stability and minimal innovation, we find that the era of incremental change can be actually quite dynamic. Through our research into the period of time following the emergence of a dominant design in automotive emission control systems, we find that the overall product innovation in the industry did not decline immediately following the dominant design, and increased throughout the era of incremental change. Further, we find that firms maintain their attention on the same core components that they innovated upon before the dominant design, but that these components make up less of the overall proportion of total innovation throughout the era of incremental change. Finally, we found that the concentration of innovating firms in the industry increases immediately following the dominant design, and this concentration decreases over time throughout the era of incremental change. Findings imply a pattern of contraction and expansion in the era of incremental change that extends previous work on the technological product life cycles and helps to characterize the era of incremental change in a novel way.     

Measurement in speed skating tournaments

Twenty principal components analyses were performed on the results of 10 European and 10 World male speed skating championships. The first principal component obtained was defined as ‘the ability to skate well at all tournament distances’. Therefore the rank order of the participants’ skating ability could be estimated in an alternative way to allow validation of the scoring method currently in force. This validity coefficient turned out to be so high (r = 0.967) that it does not seem necessary to adopt a more sophisticated method, despite a few demonstrable shortcomings of the one in use. However, there remains a considerable proportion of variance (10–34%) that can not be explained by systematic aspects of skating ability.     

四字格套语结构浅析

四字格套语结构与成语十分相似,但就其在框架性、字面性、生成性等特点方面又与成语有明显的区别。本文对四字格套语结构的特点、嵌入成分的选择及作用等几方面进行了浅略分析,并对其增强修辞效果和丰富语言表达方式的作用给予了充分肯定。     

External Visual Representations in Science Learning: The case of relations among system components

The present paper reports on a study that examined whether practical work can be said to have affective outcomes, and if so in what sense. The term ‘affective’ is used here to refer to the emotions, or feelings, engendered amongst pupils towards school science in general, or one of the sciences in particular. The study is based on 25 multi‐site case studies that employed a condensed fieldwork strategy. Data were collected, using tape‐recorded interviews and observational field notes, in a sample of practical lessons undertaken in English comprehensive (non‐selective) schools during Key Stages 3 and 4 (ages 11–14 years and 15–16 years, respectively). The findings suggest that whilst practical work generates short‐term engagement, it is relatively ineffective in generating motivation to study science post compulsion or longer‐term personal interest in the subject, although it is often claimed to do so. This suggests that those involved with science education need to develop a more realistic understanding of the limitations of practical work in the affective domain.     

A Placement Study in Secondary School Economics

Quite often in data reduction, it is more meaningful and economical to select a subset of variables instead of reducing the dimensionality of the variable space with principal components analysis. The authors present a neglected method for variable selection called the BI-method (R. P. Bhargava &; T. Ishizuka, 1981). It is a direct, simple method that uses the same criterion—trace information—used in ordinary regression analysis. The authors begin by discussing the nature and properties of the BI-method and then show how it is different from other existing variable selection methods. Because the BI-method originally was applied to small datasets that had little or no relevance to psychology or education, the authors apply it to large datasets with relevance to the psychological and educational literature. Of particular interest was the application of the BI-method to select a subset of items from a large item pool. Two practical psychometric examples with 49 and 108 items, respectively, showed that item subsets selected with the BI-method reflected the underlying structure of the whole item pool and that the scales based on those item subsets showed good reliability and predictive validity. The appropriateness of this item selection method within the context of the domain-sampling model is discussed.     

贮藏温度对鱼腥草地下茎保鲜效果的研究

将鱼腥草地下茎置于室温(30±2℃)、19±1℃和4±1℃下贮藏,研究贮藏温度对其外观、营养成分含量变化的影响.室温下,2d后,根变黑,茎变绿色,有的茎尖已腐烂;5d后,已不能食用.19±1℃下,9d后,根、茎尖、茎切口处开始腐烂;22d后,已不能食用.4±1℃下,32d后,茎切口开始腐烂,根干枯;42d后,已不能食用.三个温度下,含水量、脂肪、蛋白质都是随着贮期的延长而缓慢的降低;维生素C的含量都是随着贮期的延长先升高后降低;可溶性糖在室温下随贮藏期延长而升高,其余两个温度下随着贮期的延长先升高后降低.