Effects of power variation on cycle performance during simulated hilly time-trials     

Marc S. Wells 《European Journal of Sport Science》2016,16(8):912-918

It has previously been shown that cyclists are unable to maintain a constant power output during cycle time-trials on hilly courses. The purpose of the present study is therefore to quantify these effects of power variation using a mathematical model of cycling performance. A hypothetical cyclist (body mass: 70?kg, bicycle mass: 10?kg) was studied using a mathematical model of cycling, which included the effects of acceleration. Performance was modelled over three hypothetical 40-km courses, comprising repeated 2.5-km sections of uphill and downhill with gradients of 1%, 3%, and 6%, respectively. Amplitude (5–15%) and distance (0.31–20.00?km) of variation were modelled over a range of mean power outputs (200–600?W) and compared to sustaining a constant power. Power variation was typically detrimental to performance; these effects were augmented as the amplitude of variation and severity of gradient increased. Varying power every 1.25?km was most detrimental to performance; at a mean power of 200?W, performance was impaired by 43.90?s (±15% variation, 6% gradient). However at the steepest gradients, the effect of power variation was relatively independent of the distance of variation. In contrast, varying power in parallel with changes in gradient improved performance by 188.89?s (±15% variation, 6% gradient) at 200?W. The present data demonstrate that during hilly time-trials, power variation that does not occur in parallel with changes in gradient is detrimental to performance, especially at steeper gradients. These adverse effects are substantially larger than those previously observed during flat, windless time-trials.  相似文献   

基于等级制的清代古建筑大式大木作模式化结构设计方法     

龚清宇 《天津大学学报(英文版)》2002,8(1):16-21

采用数学表达式 ,为了解清代建筑等级制度以及大式大木作设计和构造提供了科学框架 .清代大式大木作采用预制构件 ,便于组装 ,依据严格的等级制度 ,具有高度标准化和模式化特点 .其设计过程是首先按等级确定基本模度 (斗口 ) ;再确定其平面开间、进深以及横剖面的攒数、跨度及檩数 ;最后选定屋顶形式 ,确定纵剖面与立面 .文中导出描述平面布局、屋面曲线、庑殿顶推山和歇山顶收山的数学表达式  相似文献   

注重过程教学，培养数学能力     

樊卫平 《雁北师范学院学报》2001,17(5):90-91

数学教学应改变的单纯注重结论的教学方式，而应注重整个教学过程，诸如某一知识产生的历史背景，知识间的相互联系，数学知识的实际应用以及数学思想的启发等，这样才能引起学生学习的兴趣，进而提高数学能力。  相似文献   

Mathematical Modeling in the Primary School: Children's Construction of a Consumer Guide     

Lyn D. English 《Educational Studies in Mathematics》2006,63(3):303-323

This paper examines 6th grade children's local conceptual development and mathematization processes as they worked a comprehensive mathematical modeling problem (creating a consumer guide for deciding the best snack chip) over several class periods. The children and their teachers were participating in a 3-year longitudinal teaching experiment in which sequences of mathematical modeling problems were implemented from the 5th grade (10 years of age) though to the 7th grade. In contrast to traditional problem solving, mathematical modeling requires children to generate and develop their own mathematical ideas and processes, and to form systems of relationships that are generalizable and reusable. Reported here is a detailed analysis of the iterative cycles of development of one group of children as they worked the problem, followed by a summary of the mathematization processes displayed by all groups. Children's critical reflections on their models are also reported. The results show how children can independently develop constructs and processes through meaningful problem solving. Children's development included creating systems for operationally defining constructs; selecting, categorizing, and ranking factors; quantifying quantitative and qualitative data; and transforming quantities.  相似文献   

城市交通外部成本量化方法研究     

高婷婷  闫光辉  童敏勇 《天津工程师范学院学报》2007,17(3):52-54

通过对城市中几种常见的出行方式,主要包括:步行、自行车、摩托车、公共汽车、小汽车和出租车等在外部成本方面的数量化研究,提出计算城市交通外部成本的数学模型,并通过案例进行了分析。旨在为交通政策的制定及交通资源的合理利用提供科学依据,以促进城市交通的可持续发展。  相似文献   

雷电损坏电视机的机理分析     

廖北文 《衡阳师范学院学报》1990,(3)

本文运用电磁感应原理分析了雷电的电磁效应及产生原理,阐明了雷电感应具有大电流、高电压的特点和雷电所产生的电磁场具有高频电磁波的性质,论述了雷电损坏电视机的机理和避雷防雷措施。  相似文献   

概率论诞生的思想历程   总被引：1，自引：0，他引：1  

徐伯华 《咸阳师范学院学报》2006,21(4):16-19

从随机现象的经验探索到概率论学科的形成,经过了千余年的时间。数学家从骰子赌博的问题讨论中发展出概率思想是人类认识史上光彩篇章,值得后人学习和体会。  相似文献   

对<数学课程标准>的几点认识与思考     

张绍康 《昭通师范高等专科学校学报》2003,25(5):61-64

阐述了对《数学课程标准》的认识以及贯彻《数学课程标准》应注意的一些问题．  相似文献   

感性设备同名端的判断     

万学斌 《孝感职业技术学院学报》2002,5(1):76-79

本文介绍了一些常见感性设备同名端判断的方法,对其正确使用和维护有重要的实际意义。  相似文献   

新技术下的中专教学教材探索     

王辉 《渭南师范学院学报》2002,17(2):72-75

新技术（计算机、计算器、网络）使学生更接近数学概念和拥有数学经验，使数学探索、数学实验以及提高概念的学习效果成为可能。  相似文献