正态分布点集的凸包加速算法及加速因子分析

研究了怎样对于服从正态分布的平面点集进行的凸包算法加速,理论上计算了最适合的加速因子,同时通过相应的加速因子得到正态点集分布的凸包算法最优复杂度O(n)。     

单层网壳结构整体稳定性分析

整体稳定性是单层网壳结构设计中的一个关键问题。文章通过对单层网壳结构稳定性理论进行研究,综合现有的网壳稳定性分析方法,按照钢结构设计规范和网壳结构规程的要求,对单层网壳结构进行整体稳定性设计分析。     

对学生求球壳、球体转动惯量计算中的错解分析

分别介绍了学生求球壳、球体对直径转动惯量的两种计算方法,对两种方法对比分析,指出错误解法的原因,得出运用微元法求旋转曲面,旋转体转动惯量时的正确方法。     

私募股权投资基金退出机制研究

本文从资本流动,收益实现,风险规避和提振经济等四个方面,阐述了退出对私募股权投资的重要性。国际私募股权投资市场三种主要退出方式为首次公开上市、产权出售和资产清算,这三种退出方式各有优缺点。在我国私募股权投资退出中,政府应大力发展产权交易市场,并建立健全法律法规,投资公司应重视退出策略制定,在退出方式上采用借壳上市,买壳上市,APO和混合退出模式等。     

从VP壳理论看汉语容纳句式的生成

容纳句式是汉语中一种特殊的句式。在生成语言学的框架内,各种类型的容纳句式可以统一用VP壳理论来分析其生成,即各容纳句中均具有一个轻动词,该轻动词的强语素特征会促发下层结构的移位,从而形成这一特殊句式。     

周期系相邻元素电离势的相关性

作者旨在研究(不同种类)相邻元素相同亚层的电子相关性质,而不像以往仅仅限于同一种元素原子内电子的相互作用.从总结现代原子电离势实验数据的规律性出发,发现了周期系相邻元素电子间的相关性方程 I_n〔X〕-2I_(n-1)〔Y〕+I(n-2)〔Z〕=K 文中运用“相对论效应”、“原子轨道能量变化图”解释了一些元素的部分电离势国际实验值在本文相关性中表现出的客观反常因素,并发现11种元素的15个电子国际电离势实验数据有测量误区,本文对其真值作了相应的理论预测.文章认为演化至今的不同种类元素,都是某种普遍相关联系和不断发展的产物.     

108 m×90 m柱面网壳整体提升施工方法

本文介绍河南省鸭河口电厂干煤棚柱面网壳的施工方法———"折叠展开式"整体提升施工技术.文中详细阐述了这项施工技术的基本思想、关键技术、施工过程和效益分析.这项新技术在国内尚属首次采用,应用于亚洲最大跨柱面网壳的施工中并取得了圆满的成功,证明了这项新技术的正确性和实用性.     

Maria Goeppert Mayer

This is a brief biography of Maria Goeppert Mayer. We have tried to emphasise that even outstanding women like her had to suffer (and still suffer) great discrimination. In spite of the handicaps she achieved the highest scientific distinction. B Banerjee, after his retirement from Tata Institute of Fundamental Research, has been teaching in the Physics Department, University of Mumbai. He is mainly interested in the application of nuclear physics to astrophysics and cosmology.     

Jason Lezak again and again - linear mixed modelling analysis of change–over times in relay swimming races

The aim of this study was to examine the importance of the change-over time in swimming relay races. Top-class international 4 x 100 m freestyle races were analysed across a 10-year period including three Olympic Games and five European and World Championships. A total of 220 swimmers (116 female, 104 male) were included in this study with an average participation of 1.7 ± 1.2 races. To consider such repeated measurements and other factors (e.g., ranking in the relay race, position in the relay team) linear mixed models for longitudinal data were used for the statistical evaluation. Our results showed significantly longer change-over times for male medallists (0.23 ± 0.08 s) than non-medallists (0.20 ± 0.09 s) which reflects a very likely effect (94.2%). Furthermore, there were significant differences in change-over times between female and male swimmers depending on the current race positions. In total, the influence of change-over time on the final performance in 4 x 100-m freestyle relay appears to be overrated in previous studies.     

Learning relay start strategies in swimming: What feedback is best?

In the past, studies and book recommendations on relay starts in swimming have been predominantly focused on the change-over time (COT) as a performance criterion. Aside from the circular backswing start with parallel foot placement, few studies have analysed differences in the take-off movement including step approaches as well. Although trends could be identified, the results remained still somewhat inconclusive. In contrast, no study has examined as has examined whether a reduction of COT in between wall contact of the income swimmer and the take-off of the outgoing swimmer is an optimal relay start strategy, as advocated by various swimming experts. Therefore, the purpose of this study was to compare two different relay start strategies: offensive strategy minimizing COT and conservative strategy to maximize horizontal peak force (HPF). In this regard, a learning intervention with 24 elite-level swimmers (12 females, 12 male) was conducted to compare both strategies regarding relay start time, HPF and COT. Subjects were randomly assigned to two feedback groups: COT versus HPF at take-off. The results of this study showed a clear advantage for HPF feedback for relay start performance measured by wall contact of the incoming swimmer and head passage at 7.5?m of the outgoing swimmer. In addition, similar reductions in COTs were found in both training groups. In conclusion, swimmers should focus on force production rather than minimizing COT. For the latter, deteriorating consequences for force production must be considered.