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二泡沫与木制骨架结构的对比
上期通过小模型试验机的制作,基本解决了超轻型模型的布局问题。但试验机的机翼是以泡沫材料为主,不带副翼等操纵舵面,与笔者最终的目标还有很大差距。因此,接下来需解决的问题是:制作一架带副翼的木制骨架结构模型飞机,它可否比相同尺寸的泡沫材料模型飞机更轻? 相似文献
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泡沫材料有质轻质软、浮力大等特点,在垂钓中有广泛的应用。作钓饵使用在野外很容易找到经长时间风吹日晒后已龟裂的泡沫材料,这种老化的泡沫材料中易抠出泡沫小球,用这种泡沫小球作钓饵采取动态钓法易钓获餐鲦和翘嘴鱼白等鱼。作浮子使用在用海竿做窝钓时,利用对岸固定参照物可以确定钓点的左右距离,但远近距离不好把握。这是可以用小筏把诱饵投下后,再投下两支泡沫材料浮子,用细绳或废旧钓线系紧浮子,其长度略大于水深,另一端系一石头,将两只浮子投放在窝点两边1 ̄2米处,让窝点位于两浮子中间,这样投竿时不会出现大的偏差。作绕线板使用将… 相似文献
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泡沫垫是一种由国际环保组织认证,PE材料发泡而成的新型家装材料,它具有环保、轻便、安全、经济等优点。跳跃类内容教学中通常采用小垫子进行教学,通过把小垫子折叠、展开、竖立等方法,解决跳跃时远度和高度的层次递进问题,也可以利用泡沫垫弥补教学器材不足的问题。 相似文献
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<正>在我们日常生活中,随处可见包装水果用的白色泡沫网,其实,这种所谓一次性的泡沫网有很多"剩余价值",前一段时间,中央电视台生活栏目曾介绍了一些有关泡沫网的另类用途,如清洁卫生、保护水杯……另外,在体育教学中合理利用这种泡沫网也能发挥很 相似文献
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This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue. 相似文献
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Roy J. Shephard 《Journal of sports sciences》2013,31(7):603-620
The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae. 相似文献
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重新认识体育的社会关联 总被引:3,自引:1,他引:2
体育与政治之间存在一个悖论,体育的发展与经济实力之间没有直线相关,体育与教育部分重叠,体育与宗教最为近缘,体育可借用科学手段,体育的艺术禀性日益明显,体育与养生反映着两种人生观。 相似文献
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本文在专家访谈、问卷调查、数理统计和文献资料分析的基础上,探析了上海社区体育竞赛参与者的特点、参与者对社区体育赛事运作管理的看法等问题。在此基础上从引进社区体育赛事的志愿者、整合社区体育赛事的各种资源、开发社区体育竞赛的无形资产、组建非营利性的专业团队、规范社区体育赛事的服务管理等方面提出了进一步满足上海社区居民日益增长的体育竞赛参赛需求的对策与措施。 相似文献
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对全面把握游泳训练环节的探讨 总被引:4,自引:0,他引:4
从系统观点出发,结合训练实践,对全面把握游泳训练环节进行探讨。认为应强化非智力因素在运动员多年训练中的作用,在育材全过程中不断选材,从整体上把握动态训练的全过程,把培养高水平运动员的整个过程置于一个严格的科学控制之下。 相似文献
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影响和限制耐力性运动项目的成绩的生理因素是复杂的和多方面的,取决于训练的强度和运动成绩.大强度持续性运动可导致呼吸肌疲劳.运动性呼吸疲劳可能在决定运动耐量方面起到关键的作用:一方面通过直接影响运动肌力量的生成(外周疲劳),另一方面,通过肢体用力自感不安反馈引起工作肌运动单位输出功率下降(中枢疲劳).对呼吸肌进行训练,可能有助于提高耐力性项目的运动成绩. 相似文献
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结合欧洲足球技战术的发展特点,就鲁能泰山足球队的体能训练、技术训练、防守阵型、进攻方式、定位球、职业态度、球星培养等诸方面所存在的不足进行了分析,提出相应的改进意见。 相似文献
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朱新新 《体育科技文献通报》2010,18(3):52-53,57
本文运用文献资料法,逻辑分析法,在遵循逻辑学、哲学、心理学原理的前提下,对竞技健美操技术的概念进行了界定,对竞技健美操技术进行了分类研究,在此基础上分析了竞技健美操技术的结构,为系统、科学的组织竞技健美操的教学和训练提供理论上的参考,为促进竞技健美操理论体系的完善和协调发展做出一定的贡献。 相似文献