毽球倒勾技术与训练

介绍了毽球倒勾技术的训练原则、训练步骤、训练方法、有拦网的训练和倒勾技术训练应注意的事项。     

试析散手比赛中的重击

“重击”不但成为有效的得分手段，而且效果显著可直接获优势胜利。散手运动实践表明，灵活、巧妙地运用重拳或横踢腿击头，最易达到“重击”的目的。本文举例说明在主动进攻及防守反击中实施重击的技巧。     

跆拳道540°后旋踢技术成功要素分析

540°后旋踢技术是现今自由品势和击破示范的代表性技术,其动作华丽难度高。本研究运用影像测量方法获取2014年3月韩国击破王大赛成功选手和失败选手的540°后旋踢技术各环节运动的运动学数据,通过运动学的分析探索540°后旋踢技术的成功要素,以期对自由品势选手的教学与训练提供科学依据。     

泰拳拳法及腿法技术学习认识误区研究

泰拳项目,作为在全世界范围内有着很深影响的搏击项目,在中国也越发受到武术爱好者们的欢迎,但是大家对泰拳技术的认识却存在着一定的误区,文章通过对普遍存在于搏击爱好者中的泰拳认识误区进行分析,以期能够对搏击爱好者起到一定的学习帮助作用。     

全自动数字水下地形测量系统在工程水文勘测中的应用

随着GPS技术的不断发展,RTK技术的出现,以及计算机技术的高速发展,使得平面定位技术实现了高精度、自动化、数字化、实时化,而随着测深技术的数字化、自动化,为水下地形测量的数字化、自动化提供了基础,为工程水文勘测提供了先进的手段。本文就全自动数字水下地形测量系统的组成、工作原理、作业方法进行了介绍,并根据工程实际,对其测量精度、误差源进行了分析。     

GAPS超短基线声学水下定位技术及其在海洋调查中的应用

GAPS水下定位系统是法国IXSEA公司开发的一套便携式声学超短基线水下定位系统,具有安装方便,操作简单、精度高等特点。本文分析了水下定位系统的分类和原理,并以GAPS超短基线水下定位系统为例分析了其组成,原理,工作过程及误差分析,并简单介绍了其在海洋地质调查中的应用。     

三亚俱乐部休闲潜水运动初次参与人群的水下适应研究简

以三亚俱乐部休闲潜水运动初次参与人群为研究对象,结合潜水运动的特点进行分析研究,以期为休闲潜水运动提供理论依据。     

Unsteady flow phenomena in human undulatory swimming: a numerical approach

The undulatory underwater sequence is one of the most important phases in competitive swimming. An understanding of the recurrent vortex dynamics around the human body and their generation could therefore be used to improve swimming techniques. In order to produce a dynamic model, we applied human joint kinematics to three-dimensional (3D) body scans of a female swimmer. The flow around this dynamic model was then calculated using computational fluid dynamics with the aid of moving 3D meshes. Evaluation of the numerical results delivered by the various motion cycles identified characteristic vortex structures for each of the cycles, which exhibited increasing intensity and drag influence. At maximum thrust, drag forces appear to be 12 times higher than those of a passive gliding swimmer. As far as we know, this is the first disclosure of vortex rings merging into vortex tubes in the wake after vortex recapturing. All unsteady structures were visualized using a modified Q-criterion also incorporated into our methods. At the very least, our approach is likely to be suited to further studies examining swimmers engaging in undulatory swimming during training or competition.     

Hierarchical self-localization of underwater wireless sensor network nodes

The follow-up application of underwater wireless sensor network is influenced by accuracy of self-localization of nodes. The self-localization of nodes is discussed in this paper. First of all, nodes of underwater wireless sensor network are classified into several levels according to the accuracy of position of nodes and the levels are from the first to the fifth in accordance with accuracy of nodes from high to low respectively. Secondly, the level of anchor nodes can be known by those unknown nodes from the information given by the anchor nodes themselves, At the same time the unknown nodes are able to be located in the area controlled by the first level of anchor nodes that are as the aggregation. Then the positioning algorithm is designed correspondingly in accordance with the accuracy level of nodes. Finally, the positioning algorithm is simulated and analyzed. The result shows that the unknown nodes can be located effectively by hierarchical control.     

影响武术旋风脚720°完成的生物力学探析

转动惯量的大小、分布和转轴的位置是决定720°旋风脚顺利完成的关键。好的身体姿态能促进转动惯量和角速度的调整。腾空高度是影响720°旋风脚空中转体与落地稳定性的重要因素,空中转体的速度能弥补运动员腾空高度的不够。在720°旋风脚踏跳时,身体已经绕纵轴拧转了一定的角度,这是因为偏心力矩存在而产生的,在适当的倾斜角度内产生的偏心力矩对完成720°旋风脚转体非常有利。