移动从动件盘形凸轮压力角的分析

通过对移动从动件凸轮轮廓曲线的几何分析,运用三心定理得出凸轮压力角的计算公式,用Excel准确计算出凸轮轮廓曲线上各点的压力角后运用图表分析不同运动规律、不同升程及不同偏心距的情况下凸轮轮廓曲线上各点压力角的变化规律。     

Understanding aims and values of science: developments in the junior cycle specifications on nature of science and pre-service science teachers’ views in Ireland

Irish science education is aiming to develop post-primary students’ knowledge of and about science through the introduction of ‘nature of science’ (NOS) in the new junior cycle science specification. This study aimed to investigate pre-service science teachers’ views about a particular aspect of NOS, namely the aims and values of science. Aims and values in relation to science can be considered from epistemic, cognitive, cultural, social, political, moral and ethical perspectives. In this paper, we focus on the epistemic, cognitive and social aims and values of science to provide a broad overview and investigate pre-service science teachers’ understanding of them. Qualitative methods are used to highlight two case studies that provide an in-depth record of how pre-service science teachers interpret aims and values of science. Although the sample is limited in terms of its generalisability to pre-service teacher education at large, the study provides a framework for (a) what to target and investigate about NOS in science education, particularly about aims and values of science, and (b) how pre-service science teachers are likely to make sense of such relatively new curricular goals. Implications for pre-service science teacher education are discussed.     

Acute effects of different warm-up protocols on highly skilled golfers’ drive performance

Previous research has highlighted the positive effect that different warm-up protocols have on golf performance (e.g. Sorbie et al., 2016; Tilley & Macfarlane, 2012) with the design of warm-ups and programmes targeting and improving golf performance through the activation and development of specific muscle groups. This study aimed to examine the acute effects of two warm-up protocols on golf drive performance in comparison to a control condition. Using a randomised counterbalanced design over three testing sessions, twenty-three highly skilled golfers completed the control, dynamic and resistance-band warm-up conditions. Following each condition, a GC2 launch monitor was used to record ball velocity and other launch parameters of ten shots hit with the participants’ own driver. A repeated-measures ANOVA found significant increases in ball velocity (η_p² = .217) between the control and both the dynamic and resistance-band warm-up conditions but no difference between these latter two, and a reduction in launch angle between control and dynamic conditions. The use of either a dynamic stretching or resistance-band warm-up can have acute benefits on ball velocity but golfers should liaise with a PGA Professional golf coach to effectively integrate this into their golf driving performance.     

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

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.     

三维资本视阈下的高校毕业生初次就业满意度实证分析

通过社会资本、人力资本和心理资本等三维资本,利用回归方法对高校毕业生初次就业满意度进行实证分析。人力资本对高校毕业生初次就业起着核心的配置性作用,实习经历显著影响着初次就业满意度;心理资本对初次就业满意度有着重要影响,乐观、自信可以显著提升初次就业满意度;社会资本广度对初次就业有着显著作用。高校毕业生利用资本的生产收益性,树立三维资本的投资理念,提升初次就业满意度;政府完善就业政策,限制社会资本的不公平逐利性,防止社会资本在市场竞争中滥用;高校加大就业帮扶,减少三维资本缺失带来的个体就业障碍。     

我国男子高水平三级跳远运动员专项力量训练安排研究

摘要：男子三级跳远是我国参加奥运会田径比赛的潜优势项目,专项力量是影响三级跳远比赛成绩和技术水平提升的关键因素,运用文献资料法、专家访谈法、实地调查等研究方法,分析研究我国最优秀的6名男子三级跳远运动员专项力量训练安排。结论：1）我国男子高水平三级跳远运动员的力量训练内容、方法手段、计划与负荷基本符合世界潮流,但训练中缺少单腿支撑进行的蹲、拉、提、举等练习,不够贴近专项需要;2）专项力量训练器材与世界发达国家相比科技化含量不高;3）专项力量负荷调整控制主要依赖教练员经验与身体素质指标推算。     

竞技武术套路中腾空摆莲B 和C 级跳跃落地稳定性的研究 杨乃

竞技武术套路中腾空摆莲B和C级跳跃落地接马步是长拳、南拳武术项目的两个难度动作.通过对该组动作落地技术的动力学及相关稳定性因素的分析,提出合理的落地技术和训练中需解决的问题.采用录像观察与试验分析相结合的方法,针对男女运动员的腾空与落地的特点,提出相应的解决办法和训练理论.     

摆动腿在跳远起跳技术中的运动力学分析

本文以参加2005年5月全国田径大奖赛宜兴站暨亚洲田径锦标赛的16名女子跳远运动员为研究样本,对我国优秀女子跳远运动员摆动腿摆动技术的运动学特征进行研究,揭示其在运动学方面的变化特征、范围及相互关系,评价其技术特点。以期对提高我国跳远的技术水平带来一定的实际意义。     

对中国古典舞动作“紫金冠跳”的生物力学研究

运用运动生物力学三维录像解析与三雏测力的方法,对中国古典舞动作“紫金冠跳”在蹉步、起跳、空中舞姿成形及落地缓冲四个阶段进行运动学与动力学的量化研究,旨在为舞蹈训练科学化进程起到抛砖引玉的作用。     

动作协调与"爆发力"表现田径跳跃动作协调能力测量与评价方法研究

通过专家访谈与问卷调查,确定了6组12项动作指标作为协调能力测试行为样本。运用生物力学方法与人体运动的动力学方法,以相同动作冗余自由度的控制与不控制作为刺激变量,以动作爆发力表现水平的差值为因变量,通过对两组不同水平被试测验成绩的比较,对跳跃专项动作协调能力进行了定性与定量评价。