内圆柱与外圆筒间相对滑动对圆柱套筒沿斜面向下滚动时间的影响

从经典力学定律出发,求出了圆柱套筒从斜面顶端由静止开始沿斜面向下滚动到底端的过程中所需时间的解析式,并给出了外圆筒与内圆柱体有相对滑动时比无相对滑动时所需时间更短的理论依据,从而证明了实验结果的正确性.     

一种特殊的英语从句

名词性关系从句的深层结构与其表层结构不一致。正因为如此,这种从句即是一种特殊的关系从句又是一种特殊的名词性从句。     

经济指数三种形式的几个问题

从指数的历史来阐明综合指数、平均数指数和平均指标指数名称的来源,分析这三种指数应用条件上的不同,和它们之间的互相关系。     

复函数芽截断的相对S-C~0-充分性的判定

研究复函数芽截断的相对S-C0-充分性,将原有的复函数芽截断的C0-充分性推广到复函数芽截断的相对S-C0-充分性,并得出相对S-C0-充分性的判别方法。     

论定罪与量刑的关系模式

定罪与量刑的关系模式是我国量刑程序改革理论上的争点与实践中的难点。探寻一种适合我国国情的定罪与量刑关系模式,对推动我国量刑程序改革的深入进行有着非常重大的意义。对于被告人认罪案件,各界普遍认为应适用相对独立的量刑程序,目前专家学者们的分歧在于对被告人不认罪的案件应适用相对独立的量刑程序还是独立的量刑程序。各地方法院量刑程序改革试点的实践证明,对于被告人不认罪案件的审理,独立的量刑程序更具科学性与合理性。     

Relative Age Effects are a developmental problem in tennis: but not necessarily when you’re left‐handed!

Relative Age Effects (RAEs), describing attainment inequalities as a result of interactions between biological age and age‐grouping procedures, have been demonstrated across many sports contexts. This study examined whether an additional individual characteristic (i.e., handedness) mediated RAEs in tennis. Relative age and handedness distributions of 1027 male professional tennis players ranked in the year‐end ATP Top 500 for 2000–2006 were analyzed. Relatively older players, born in the first two quartiles, were over‐represented for right‐handed players (86.56%), whereas no RAEs were found for left‐handers (13.44%). Findings seem to suggest that left‐handers in tennis gain advantages that circumvent the RAE problem.     

置换法测金属原子量实验的微型化

对置换法测金属原子量实验进行了微型化研究,改进了实验装置,实现了药品的微量化．与常量制备的方法相比较,具有节约药品、省时、装置简便、操作安全快速等优点．     

相对论效应对含碘复合物非键作用的影响研究

本文通过几个简单含碘复合物的相对论密度泛函计算,考察了相对论效应对碘键作用的影响。最后结果表明相对论效应对碘键作用影响较小,一般计算时可以忽略,采用pbeO／6—311G^＊或pvDZ、pvTZ基组可以很好地描述含碘复合物,而选择好的相关能方法则是成功计算相对论效应的关键。     

Influence of birth quarter on the rate of physical activities and sports participation

Abstract

The purpose of this study was to assess the potential influence of birth quarter on the frequency of physical activity and participation in specific activities during adulthood. We used data from one national and one provincial survey, the 2005 Canadian Community Health Survey and the 1998 Quebec Social and Health Survey (Enquête sociale et de santé du Québec) respectively. We analysed the distribution of participants at each level of practice of a given leisure activity and work-related physical activity. In the Canadian Community Health Survey, a relative age effect was found for participation in soccer in the 25- to 60-year-old population. However, for volleyball, a significant relative age effect was also observed but with over-representation of the last quarters of the year for the whole population and for men aged 12–60 years. In the Quebec Social and Health Survey, significant differences in the frequency of distribution without a relative age effect were revealed for participation in women's ice hockey, work-related physical activity level, and stage of change for physical activity. Overall, the data indicate that the systematic relative age effect reported in other studies for some competitive sports, such as ice hockey and soccer, is not as prevalent in leisure physical activities during adulthood. This may reflect lower competitive selection and attrition in population physical activity compared with competitive sports in younger athletes.