一种平面四连杆机构轨迹综合的新方法     

楼进 《上海海事大学学报》1994,(4)

根据平面闭合曲线切线象理论，定义了切线全旋转角的概念，提出并论证了一种用曲线的曲率关于切线全旋转角的函数和进行平面四连杆机构轨迹综合的新方法。这是一种可应用于工程设计的几何系统分析法。  相似文献   

Knots in the Fourth Dimension     

《Cultural and Social History》2013,10(1):31-49

ABSTRACT

The article analyses a debate that preoccupied the Russian press in the winter of 1878/9. Writers, journalists and scientists discussed whether mathematics could explain spiritualist séance phenomena. At its core, this was an assessment of social change and a debate about the ambiguity of modern life. While spiritualists hoped to bridge the divide between science and religion, subjectivity and objectivity, their opponents feared that séance phenomena and modern mathematics undermined a rationalist world-view that was endowed with reliability and universal truth. That no agreement could be reached indicates that the post-reform public sphere had become truly pluralist and modern.  相似文献   

A descriptive study of step alignment and foot positioning relative to the tee by professional rugby union goal-kickers     

John Cockcroft 《Journal of sports sciences》2016,34(4):321-329

This study describes foot positioning during the final two steps of the approach to the ball amongst professional rugby goal-kickers. A 3D optical motion capture system was used to test 15 goal-kickers performing 10 goal-kicks. The distance and direction of each step, as well as individual foot contact positions relative to the tee, were measured. The intra- and inter-subject variability was calculated as well as the correlation (Pearson) between the measurements and participant anthropometrics. Inter-subject variability for the final foot position was lowest (placed 0.03 ± 0.07 m behind and 0.33 ± 0.03 m lateral to the tee) and highest for the penultimate step distance (0.666 ± 0.149 m), performed at an angle of 36.1 ± 8.5° external to the final step. The final step length was 1.523 ± 0.124 m, executed at an external angle of 35.5 ± 7.4° to the target line. The intra-subject variability was very low; distances and angles for the 10 kicks varied per participant by 1.6–3.1 cm and 0.7–1.6°, respectively. The results show that even though the participants had variability in their run-up to the tee, final foot position next to the tee was very similar and consistent. Furthermore, the inter- and intra-subject variability could not be attributed to differences in anthropometry. These findings may be useful as normative reference data for coaching, although further work is required to understand the role of other factors such as approach speed and body alignment.  相似文献   

从彩陶纹样看几何化装饰风格的发展变化     

张洁玉 《泰州职业技术学院学报》2007,7(3):44-47

阐述彩陶文化的不同类型的装饰纹样特点，从中探索几何化装饰风格的发展趋向和规律，探索几何化装饰风格发展的社会因素和技术因素。  相似文献   

高中几何课程标准之我见   总被引：5，自引：1，他引：5  

王建明  张思明  王鹏远  赵大悌  刘美伦 《数学教育学报》2001,10(4):55-58

高中几何课程设计应该使学生在现实的和未来的学习经验（知识的经验和实际的经验）中，提升他们对几何价值的认识，高中几何课程标准的过程标准应该包括推理与证明、问题解决、多重表示和交流与合作，过程标准贯穿于教学内容标准之中。  相似文献   

标准配极对应和代数对偶原理     

彭群钦 《邵阳学院学报(社会科学版)》1995,(2)

本文首先建立了标准配极对应,从而为代数对偶原理提出了理论依据。并进一步在欧氏平面上提出了一系列对偶命题和阐述标准配极对应的应用。  相似文献   

“初等几何研究”课程改革与实践   总被引：4，自引：0，他引：4  

李文铭 《数学教育学报》2002,11(1):72-74

随着数学教育的深入发展，高师数学教育课程的势在必行。“初等几何研究”课程的教学大纲需要重新制订，其课程体系和教学内容也需要大幅度调整，特别是将原来的“初等几何研究”课程和“高等几何”课程合并成为一门课程，并将该课程的教学目的从初等几何“研究”转到初等几何教学素质的培养上来。与此同时，编写中的教材《初等几何教学基础》也必须突出与数学教育改革思路相适应的特色。  相似文献   

面向制造的板级电子电路产品多信息模型研究     

李春泉  周德俭  俞涛 《上海大学学报(英文版)》2004,8(Z1)

Most electronics products use PCB to carry electronic circuits. This paper classifies information contained in PCB-based electronic circuits into several models: geometry model, physics model, performance model and function model. Based on this classification, a multi-information model of product is established. A composite model of product is also created based on object-orientation and characteristics of the product. The model includes a 3D geometry model, a physics model with integrated information that can be divided into microscopic and macroscopic information, a generalized performance model and a function model that are from top to bottom. Finally, a multi-unit analysis is briefly discussed.  相似文献   

苯甲酸分子的简正振动与拉曼光谱   总被引：1，自引：1，他引：0  

韩礼刚  陶亚萍 《洛阳师范学院学报》2011,30(11):20-22

利用量子化学软件计算得出了苯甲酸分子的平衡构形,基于这个构形,理论上计算出了苯甲酸分子的简正振动光谱,并与实验测得的结果进行了比较,最后对其简正振动模式进行了全面归属.  相似文献   

Web 2.0 Tools in High School in Portugal： Creating Screencasts and Vodcasts for Learning     

Aurora Maria  Moreira Rocha  Clara Pereira  Coutinho 《美中教育评论》2011,(1):54-62

  相似文献