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Jonathan P. Norris Jamie Highton Stephen F. Hughes Craig Twist 《Journal of sports sciences》2016,34(19):1859-1866
The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HRpeak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance. 相似文献
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内蒙古商都县大石沟黑云母钾长花岗岩主要由钾长石（40～60%）、更长石（10～15%）、石英（25～32%）及黑云母（5～7%）组成.主元素SiO2含量68.25%～69.64%,K2O含量5.03%～8.03%,K2O＞Na2O;A/CNK为0.77～1.1,稀土元素分馏较强,REE配分型式具中等铕负异常,岩石地球化学特征与碰撞花岗岩类似;本文对大石沟黑云母钾长花岗岩进行高精度锆石SHRIMP U-Pb定年研究.其形成时间为342±5Ma,可能代表华北板块与西伯利亚板块碰撞阶段的岩浆热事件.区域最新研究资料表明,侵入图林凯蛇绿岩带的埃达克岩的年龄为467～429Ma,代表洋壳俯冲的消减时间;390～310Ma花岗岩侵位的SHRIMP U-Pb锆石年龄以及383Ma蓝片岩Ar-Ar年龄代表华北板块与西伯利亚板块的碰撞事件;390～342Ma和324～310Ma花岗岩可能代表碰撞阶段两期岩浆热事件产物. 相似文献
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经济的持续发展促进了我国汽车工业进入了高速发展的新阶段,随着汽车作为代步工具的逐步普及,由此引发的交通事故也层出不穷,车辆碰撞具有致死率高、破坏性强的特点,给人民群众生命安全带来了很大的威胁.文章基于车辆的防碰撞技术,对目前正在广为应用的防撞预警系统的工作原理、结构组成及特性进行了分析,并对未来发展进行了展望. 相似文献
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传感网络经常采用Flooding协议作为路由管理,但碰撞和重传会导致大量重复的数据包,造成有限资源的浪费.讨论了隐藏节点及邻居节点对碰撞的影响,并进行了仿真.结果表明当发射半径达到一定区域时,隐藏节点引起的碰撞数量达到一个峰值,从而可以通过合适的设计避免高碰撞概率的网络分布区域.另外,还可以通过增加传输延迟来减少节点碰撞. 相似文献
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汽车主动避撞系统相关技术 总被引：1，自引：0，他引：1
朱金光 《四川职业技术学院学报》2007,17(4):112-113
汽车主动避撞系统能够明显地提高交通的安全性,是智能交通系统研究的一个重要方面.文中对汽车主动避撞系统及相关技术进行介绍. 相似文献
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孙晓波 《鞍山师范学院学报》2005,7(1):93-94
20世纪工业化社会中存在的所谓的文明和人类的自然本性的冲突，揭露了资本主义社会所带来的工业化摧毁了人的本性这一事实。赞美了自然的力量，鼓舞人们追求生命的自由。 相似文献
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技术引进与技术创新的冲突和协同 总被引：3，自引：1，他引：2
本文系统地分析了在市场环境下技术引进与技术创新的冲突,论证了市场对单个企业激励引进,对行业或国家激励创新。由此引发了引进与创新的冲突。在一定条件下,企业放弃创新是行业内竞争的纳什均衡。本文提出创新机制与制度建设的必要性和对策 相似文献
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通过介绍欧洲数字图书馆的背号及发展．从中国数字图书馆的现状出发,对由此产生的文化撞击进行思考。使图书馆员意识到在文化竞争中面临的挑战和机遇,承担起历史赋予图书馆人的责任与使命。 相似文献
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Yahia Tachwali 《Journal of The Franklin Institute》2009,346(5):488-499
This paper presents research results regarding a vehicle collision avoidance system that uses a wireless sensor platform and communication based on 802.15.4 standard. The system is comprised of two components: monitoring stationary nodes mounted on the road and mobile nodes installed in vehicles. Signal strength and link quality indicators are evaluated to assist in the sequence identification of vehicles as they approach each other at an intersection. The study shows the feasibility of implementing 802.15.4 standard in wireless sensor network communication to act as a time-critical vehicle warning system that can be used for safety application. 相似文献