课堂:研究性学习的主阵地

研究性学习是以培养学生自主探索精神为特征的一种教学方式,其主阵地在课堂。只有课堂的学习方式发生变革,才能有效地促进学生研究能力的发展。     

An overview of cricket ball swing

The aerodynamic properties of a cricket ball have intrigued cricket players and spectators for years, arguably since the advent of the game itself. The main interest is in the fact that the ball can follow a curved flight path that may not always be under the control of the bowler. The basic aerodynamic principles responsible for the nonlinear flight or ‘swing’ of a cricket ball were identified decades ago and many papers have been published on the subject. Over the last 25 years or so, several empirical investigations have also been conducted on cricket ball swing, which revealed the amount of attainable swing and identified the parameters that affect it. Those findings are reviewed here with emphasis on phenomena such as late swing and the effects of humidity on swing. The relatively new concept of ‘reverse swing’, how it can be achieved in practice, and the role in it of ‘ball tampering’, are also discussed in detail. In particular, the ability of some bowlers to effectively swing an old ball in the conventional, reverse and the newly termed ‘contrast’ swing mode is addressed. A discussion of the ‘white” cricket ball used in the 1999 and 2003 World Cup tournaments, which supposedly possesses different swing properties compared to a conventional red ball, is also included. This is a current overview of cricket ball swing rather than a detailed review of all research work performed on the topic. The emphasis is on presenting scientific explanations for the various aerodynamic phenomena that affect cricket ball swing on a cricket ground.     

基于Rankine理论的挡土墙卸荷台合理位置的研究

利用朗肯土压力理论,通过对最小倾覆力矩和最小土压力的求解,得出了挡土墙卸荷台的合理位置:在距填土表面的垂直距离为墙高的1/3～1/2范围内。     

服务产业创新的"逆向产品周期"模型

有形产品创新中的“A-U模型”已成为描述制造业技术创新演变规律的一般模型,而对服务业的创新演变规律学者们至今没有形成统一的认识,也不存在一个获得普遍认可的理论模型。本文介绍Barras提出的“逆向产品周期(RReverse Product Cycle:RPC)”模型,并对模型的局限性和意义进行探讨。     

后发企业逆向创新类型与策略组合研究

摘要：近年来,在新兴市场国家,回溯创新的案例不断被发现和总结,日益要求对回溯创新的类型进行理论提炼。首先,基于企业在“创意/概念”环节与“研究开发”环节的主导深度,归纳了“弱创意、弱研发”、“强创意、弱研发”、“弱创意、强研发”、“强创意、强研发”四种典型类型。接下来,总结了同以上类型相对应的创新策略（分别谓之为“市场竞速”策略、“利基市场”策略、“开发领先”策略和“全面领先”策略）,并且指出采用这些策略企业所需要具有的能力支撑。最后,通过对相关企业不同阶段回溯创新的分析,归纳出本研究中回溯创新可以遵循的演化路径。     

闽南语“逆序词”探析

通过对闽南语"逆序词"的界定、类型、特点等方面进行的分析,预测了它的发展趋势,希望人们理性地看待它存在的问题。     

论汉代功曹、功曹史是否同职异称

史学界一般认为功曹即功曹史。宋一夫认为功曹、功曹史是两个职位,在详细推敲其各个论点论据后发现存在问题,汉代功曹、功曹史实为同职异称。     

高效课堂 环环相扣

语文教学的成败关键是课堂效率的高低。要想提高课堂教学效率,课堂教学就要环环相扣。     

藏文翻译在传播佛教文化过程中的地位和作用

藏文翻译在传播外来知识,尤其是佛教文化,以及构建具有高原特色的藏族文化方面,发挥了桥梁和纽带作用.藏文翻译为祖国文化增加了许多新元素,丰富了语言和词汇,推动了语法及文体的变化,促进了文学发展.     

核心稳定性研究历史与现状

核心稳定性是一个广泛应用于包括健康和医学领域在内的多领域的常见术语,科学文献中有关核心稳定性定义的表述各不相同。通过对“核心”的位置、核心稳定性中的稳定性的定义、核心稳定性的构成的分析,确定人体“核心”的位置,探讨“核心稳定性”中的“稳定性”的内涵,分析核心稳定性的生物力学原理。