浅谈平衡力法在物理学中的应用

平衡力是物理学中很重要而且应用又十分广泛的一个知识点,掌握好平衡力,灵活运用平衡力法讲解教学相关内容,解决相关物理题,将会使解题思路清晰,一些不易懂的原理、不好解的题目,会有“柳暗花明又一村”的效果。本文先说明什么是平衡力法,然后解读平衡力这个知识点,最后从教学角度和解题角度说明平衡力法应用的魅力所在,本文开阔视野,拓展思路,将是打开学好物理一扇窗,呈现学好物理一片天地。     

运用Web of Science做好英文科技期刊的自我评价

【目的】 探索我国英文科技期刊如何更好地利用Web of Science(WoS)数据库平台做好期刊的学术影响力指标跟踪及国际化程度评估。【方法】 以Journal of Bionic Engineering及同领域的竞争期刊为例,探讨运用WoS的自动统计分析功能进行科技期刊学术影响力指标跟踪和期刊国际化程度评估的新方法。【结果】 利用WoS的自动统计分析功能可以快速、准确地做好科技期刊的学术影响力指标跟踪及期刊国际化程度评估,帮助期刊编辑部查找不足,从而适时地调整办刊策略。【结论】 高效运用WoS等网络新兴工具可以更好地为我国科技期刊的国际化助力。     

恩格斯“历史合力论”对我国生态文明建设的价值启示

恩格斯的"历史合力论"作为唯物史观的重要组成部分,不仅具有丰富的理论内涵,而且在实践方面,对于社会主义革命运动的开展和社会主义建设的推进有着积极的指导意义。"历史合力论"强调经济因素的决定性,又不忽视经济因素与其他诸多要素的多元互动的观点表明:当前,我国在社会主义初级阶段推进生态文明建设,现代化的工业文明是生态文明建设的基本物质前提,经济建设仍是重中之重,同时经济因素之外的其他非经济因素是实现生态文明的重要辅助条件,其中广大人民群众作为历史的创造者是生态文明建设的主体力量,这几方面因素相互协调补充,缺一不可。     

合理使用与许可使用的异同及适用

版权法自产生之初,就在对版权是保护还是限制这个问题上陷入两难境地。一方面要鼓励和保护优秀作品的创作与传播;另一方面必须出于对社会公共利益的兼顾而对版权人权利加以限制。总的来看,这种限制主要包括合理使用和许可使用两个方面。     

浅论邓小平对青少年成长的关怀

邓小平同志始终以博大的胸怀和深邃的目光,站在党和国家前途命运的高度,十分关怀青少年的成长。多次向青年发出号召要做“四有”新人,要学习,要参加社会实践,并鼓励大量派遣青少年出国留学,培养了大量的青年专家。     

Impact absorption of tennis shoe-surface combinations

The aim of this study was to investigate, for typical shoes and surfaces used in tennis, the relative role of the shoe and surface in providing cushioning during running. Five test surfaces ranging from concrete to artificial turf were selected, together with two shoe models. Impact absorbing ability was assessed mechanically using drop test procedures and biomechanically using peak magnitude and rate of loading of impact force and peak in-shoe pressure data at the lateral heel. Differences in biomechanical variables between shoe-surface combinations were identified using a two-way ANOVA (p < 0.05). Mechanical test results were found to rank the surfaces in the same order regardless of the shoe model, suggesting that the surface is influential in providing cushioning. However, for all mechanical and biomechanical (p < 0.05) variables representing impact absorbing ability, it was found that the difference between shoes was markedly greater than the differences between surfaces. The peak heel pressure data were found to rank the surfaces in the same order as the mechanical tests, while impact force data were not as sensitive to the changes in surface. Correlations between mechanical and biomechanical impact absorption highlighted the importance of testing the shoe-surface combination in mechanical tests, rather than the surface alone. In conclusion, mechanical testing of the shoe-surface combination was found to provide a strong predictor of the impact absorbing ability during running if pressure data were used. In addition, for typical shoe-surface combinations in tennis, the shoe was found to have more potential than the surface to influence impact loading during running. Finally, in-shoe pressure data were found to be more sensitive than force plate data to changes in material cushioning.     

大型集装箱船的总纵强度实用计算方法

以我国１９９６年《钢质海船入级与建造规范》对大型集装箱船的总纵强度的要求为标准,讨论了具体装载状态下船舶总纵强度的校核方法,并着重探讨了在资料不完整的情况下与总纵强度校核有关的船舶资料的计算制作方法。     

400m内外侧弯道跑速度变化之研究

运用生物力学分析法，对400m栏内、外侧弯道跑的栏间跑和左、右腿攻栏的栏上技术进行分析，结果是不论右腿攻栏还是左腿攻栏，外侧跑道弯道跑成绩都好于内侧跑道弯道跑成绩。     

转型时期贵州铜仁少数民族地区劳动力转移现状及对策

受金融危机影响,我国农村劳动力转移出现了一些新特点、新趋势。通过对转型时期铜仁少数民族地区劳动力转移的现状进行分析,从而掌握铜仁地区农村劳动力资源现状,找出存在的问题,提出对策建议。     

Forefoot running requires shorter gastrocnemius fascicle length than rearfoot running

ABSTRACT

This study aimed to investigate the influence of foot strike patterns on the behaviour of the triceps surae muscle-tendon unit, including the Achilles tendon whose length nearly corresponds to force of the triceps surae, and the medial gastrocnemius muscle (MG) during running. Seven male volunteers ran with forefoot and rearfoot strikes at 10, 14 and 18 km h^?1 on a treadmill. The MG fascicle length was measured using ultrasonography. The in vivo length of the curved Achilles tendon was quantified by combining ultrasonography with optical motion capture of reflective markers on the right lower limb and an ultrasound probe. The forefoot strike resulted in a significantly shorter MG fascicle length at the initial contact, at Achilles tendon peak elongation, and at toe-off, than the rearfoot strike. The Achilles tendon length at initial contact was greater during the forefoot strike than during the rearfoot strike at 18 km h^?1, while its peak elongation was not significantly different during forefoot and rearfoot running. These results indicate that the MG, with a shorter length during forefoot running, manages to address demands for a similar peak force of the triceps surae than during rearfoot running.