足球比赛的负荷量化-结构、方法和特征     

缪律  史国生  黎涌明 《成都体育学院学报》2020,(2):93-99,106

足球比赛负荷是球员在比赛情景下完成各类动作所承受的物理、生理和心理等方面刺激之和。比赛负荷的量化结构分为外部和内部负荷,外部负荷的量化方法包括人工视频分析技术、自动轨迹追踪技术和全球定位设备,通过球员体能或技术表现的负荷量和强度来评定足球比赛中的行为活动特点,外部负荷特征表现为间歇性运动下频繁变向和短距离变速跑,高比例的中低强度无球跑穿插较少的高强度带球跑。内部负荷的量化方法包括耗氧量、心率和血乳酸等指标的测定,通过上述指标的变化幅度来评定足球比赛中的能量代谢水平;内部负荷特征表现为有氧供能为主、无氧磷酸原和糖酵解供能交替进行。现有研究局限为外部负荷低估了变向运动对足球比赛负荷的影响,内部负荷无法概括正式比赛的供能特征等。未来可尝试在优化量化方法基础上结合内外负荷,从而更精准地量化比赛负荷。  相似文献   

Bio-inspired untethered fully soft robots in liquid actuated by induced energy gradients     

Liang Xiong Lyu  Fen Li  Kang Wu  Pan Deng  Seung Hee Jeong  Zhigang Wu  Han Ding 《国家科学评论(英文版)》2019,6(5):970

Soft robotics with new designs, fabrication technologies and control strategies inspired by nature have been totally changing our view on robotics. To fully exploit their potential in practical applications, untethered designs are preferred in implementation. However, hindered by the limited thermal/mechanical performance of soft materials, it has been always challenging for researchers to implement untethered solutions, which generally involve rigid forms of high energy-density power sources or high energy-density processes. A number of insects in nature, such as rove beetles, can gain a burst of kinetic energy from the induced surface-energy gradient on water to return to their familiar habitats, which is generally known as Marangoni propulsion. Inspired by such a behavior, we report the agile untethered mobility of a fully soft robot in liquid based on induced energy gradients and also develop corresponding fabrication and maneuvering strategies. The robot can reach a speed of 5.5 body lengths per second, which is 7-fold more than the best reported, 0.69 (body length per second), in the previous work on untethered soft robots in liquid by far. Further controlling the robots, we demonstrate a soft-robot swarm that can approach a target simultaneously to assure a hit with high accuracy. Without employing any high energy-density power sources or processes, our robot exhibits many attractive merits, such as quietness, no mechanical wear, no thermal fatigue, invisibility and ease of robot fabrication, which may potentially impact many fields in the future.  相似文献   

Leg amputation side determines performance in curve sprinting: a case study on a Paralympic medalist     

Johannes Funken  Kai Heinrich  Steffen Willwacher  Ralf Müller  Jonas Böcker  Hiroaki Hobara 《Sports biomechanics / International Society of Biomechanics in Sports》2019,18(1):75-87

The lower limb kinetics of curve sprinting in amputees are not well described in the literature, particularly with respect to the effect of the side of amputation. This is an issue due to the importance of the knowledge for prosthetic design and classification of athletes. Thus, the aim of this study was to investigate the influence of side of amputation on curve sprinting performance in athletes with a unilateral leg amputation. A three-dimensional motion analysis system (Vicon), four force plates (Kistler) and a modified mathematical human model (ALASKA) were used to compare clockwise and counter clockwise curve sprinting lower limb kinematics and kinetics of a Paralympic medalist with a left-sided knee exarticular amputation. Results reveal that vertical ground reaction force application and total vertical impulse were lower when the affected limb was at the inside of the curve. The unaffected limb showed joint mechanics different to those established for non-amputee athletes and might contribute better to propulsion when being the inside limb. Curve sprinting biomechanics and the ability to attain high radial velocities are directly dependent on the side of amputation relative to the curve direction in a unilateral amputee athlete of highest performance level.  相似文献   

车辆工程专业实践教学系统的改革     

张雨 《中国现代教育装备》2011,(19):46-48,59

讨论了我国汽车产业要求将车辆工程专业内涵定位于新能源汽车的原因;提出了新能源汽车相比于传统内燃机汽车的特点;给出了以新能源汽车为专业内涵的车辆工程专业对其实践教学系统进行改革的思路,介绍了实施改革所做的工作内容。  相似文献   

穆旦:"自我"聚积起新诗的能量     

肖严 《钦州学院学报》2005,20(2):18-21

穆旦诗歌充满了不同的自我的声音,展示了人类心灵最为丰富而神秘的一面.以"带电的肉体"和"丰富而且危险"的写作方式直逼当前中国诗歌中"那一团模糊不清的诗意",颠覆了现代诗歌中残留的古典性和传统性,在此之上建立的是一个独异的穆旦世界多重、分裂的现代自我,苦涩的现代感情,人与世界、人与自身之间更加暧昧而复杂的关系.  相似文献   

普朗克与早期量子论     

王立  张小安  张辉 《咸阳师范学院学报》2002,17(2):40-43

回顾了量子力学发展初期的重要概念之一的能量子产生的背景及过程。探讨了普朗克大胆创新与守旧思想的主客观原因，以及普朗克对量子力学所做出的杰出贡献。  相似文献   

模拟情形下中国能源消费和碳排放的预测分析   总被引：1，自引：0，他引：1  

金婷婷  童霞  刘静娴 《南通职业大学学报》2021,(1):58-62

基于中国能源消费"煤多、油贫、气少"和碳排放逐年递增的现状,选取人口规模、经济发展水平、能源消费强度三个影响因子,构建STIRPAT模型,对碳排放量的影响因素进行了实证分析,并预测分析了在基准、低碳和协同低碳三种情形下中国2025—2050年的能源消费量和碳排放量。研究结果表明:在低碳情形和协同低碳情形下,中国的能源需求将分别在2045年和2035年出现拐点;协同低碳情形是实现碳排放峰值的最佳方式;在不同情形下碳排放强度虽有较大差异,但都呈现明显的上升趋势。据此提出了完善低碳经济立法、加快可再生能源发展、鼓励低碳工业化生产、加大科技创新等政策建议。  相似文献   

山东省乡村旅游动能系统测度与地域类型研究     

卢飞  颜文静  张红 《山东商业职业技术学院学报》2021,(1)

乡村旅游作为多产融合的绿色产业,在推进新旧动能转换重大工程建设中发挥着重要作用。以2018年山东省17地市为研究对象,从需求侧、供给侧和结构转换3个维度构建乡村旅游动能系统指标体系,采用因子分析法对山东省乡村动能系统进行测度,并借助聚类分析方法将乡村旅游动能系统划分为三种地域类型,在此基础上针对不同的地域类型提出相应的动能系统提升策略。  相似文献   

任务驱动教学法下的能源与动力工程基础实验实训探索和改革     

沈妍  刘锐  许啸  何晓崐  姚江 《中国现代教育装备》2021,(3)

分析能源与动力工程基础实验实训现状和存在问题,将任务驱动教学法应用于基础实验实训,突出学生为主、融入新兴理念、培养创新意识、细化实训要求、完善考核机制和扎实能力培养。通过基础实验的自学和检测,锻炼学生操作实验、撰写报告和分析结果的能力。设计实验的任务驱动,给学生充分发展的平台,锻炼其自学、实践、表达和团队协作能力,培养符合未来职业需要的应用型人才。  相似文献   

面向新工科建设的新能源汽车专业方向相关课程教学形成性评价探究     

王亚雄  陈士安  任志英 《中国现代教育装备》2021,(3)

新工科背景下,为了适应新能源汽车产业的蓬勃发展,培养新能源汽车专业人才已成为车辆工程专业教学的重要任务。在探讨面向新工科建设的新能源汽车专业方向相关课程教学形成性评价实施思路的基础上,提出了以增强工程实践能力为目标的形成性评价教学措施,旨在为新能源汽车专业方向相关课程教学中形成性评价的实施与应用提供参考。  相似文献