程控信号发生器的设计

本文介绍了利用直接数字频率合成(DDS)技术构成数字频率合成器的工作原理、电路组成、电路设计并对利用AD9850、单片机和微机来构成信号发生器作了介绍。     

阳极电催化剂在直接甲醇燃料电池的应用

直接甲醇燃料电池以燃料甲醇来源丰富，价格低廉，储存、携带方便而成为近年的研究热点。本文评述了阳极催化剂在直接甲醇燃料电池的研究概况，详细介绍了多种催化剂对甲醇氧化的作用。     

A combined approach to strengthen children’s scientific thinking: direct instruction on scientific reasoning and training of teacher’s verbal support

Inquiry-based lessons have been demonstrated to improve children’s scientific thinking (i.e. reasoning abilities and domain-specific knowledge). Although empirical evidence shows that inquiry-based learning requires instruction, research comes from two approaches that have not been bridged yet: direct instruction of scientific reasoning and teacher training of verbal support. We investigated how these two types of instruction separately or combined strengthened children’s scientific thinking by comparing four conditions: baseline, direct instruction, verbal support, and a combined approach. Effectiveness of an inquiry-based lesson series on scientific reasoning abilities, vocabulary, and domain-specific knowledge (near and far transfer) were studied among 301 fourth graders. Results showed that both approaches strengthened different components of scientific reasoning abilities, and that a combination of instructions was most effective for scientific reasoning abilities, vocabulary, and domain-specific knowledge. Domain-specific knowledge acquisition was strengthened only when both instructions were provided. It can thus be concluded that each type of instruction has unique contributions to children’s science learning and that these instructions complement each other. Our study thus showed that inquiry-based lesson series when preceded by direct instruction of scientific reasoning and scaffolded with verbal support are most effective.     

试论课程三维目标

课程目标是当前基础教育课程改革中涉及的基本问题。课程三维目标的提出是现代社会发展的需要，也是人自身发展的需要。三维目标与双基目标既有区别，又有一定联系。课堂教学改革应围绕三维目标的落实而展开。     

浅析外商在华直接投资的发展与现状

改革开放以来外商在华直接投资取得了长足发展,这对中国民族工业发展、产业结构优化、就业机会及对外贸易增长方面都起到了积极的促进作用.如何扩大利用外商直接投资,本文提出了一定的对策、建议.     

高适诗"悲壮而厚"之成因--从艺术形式方面探析

本文从艺术形式方面探讨高适边塞诗“悲壮而厚”之成因，即从意象的运用，直抒胸臆的表达方式，夹叙夹议的手法朴实而炽热的语言四方面进行分析。     

关于英语专业学生听力学习策略的调查研究

听力是一种主动的、推理性的理解过程,也是基础语言技能之一。然而对于许多学生来说听力也是一种最为费时的任务,因此它需要大量的训练和实践。文章把理论和实践结合起来,对学生在听力理解中的学习策略进行了调查性研究。     

中国吸引外商直接投资的决定因素

2002年中国吸引外商直接投资跨上了新台阶。作者认为中国稳定的政治经济环境,廉价而且不断优化的劳动力结构,逐步成型的巨大市场和不断改善的投资环境是吸引外商投资的重要因素。     

构建《高职数学教育学》之论证

高等职业技术教育在培养目标、专业设置、课程开设等方面都有自身的特点,有必要对其研讨,构建出《高职数学教育学》这门新学科。     

我国中小企业融资与金融支持

中小企业是我国经济发展的重要基础，在扩大就业、保持社会稳定、活跃市场、促进经济发展等方面发挥着重要作用。但是中小企业的融资困难，已成为其进一步发展的瓶颈。这里主要分析中小企业的重要性及其融资特点、制约因素，探讨健全中小企业的间接融资和直接融资机制等金融支持问题。