Coordination pattern of baseball pitching among young pitchers of various ages and velocity levels

This study compared the whole-body movement coordination of pitching among 72 baseball players of various ages and velocity levels. Participants were classified as senior, junior, and little according to their age, with each group comprising 24 players. The velocity levels of the high-velocity (the top eight) and low-velocity (the lowest eight) groups were classified according to their pitching velocity. During pitching, the coordinates of 15 markers attached to the major joints of the whole-body movement system were collected for analysis. Sixteen kinematic parameters were calculated to compare the groups and velocity levels. Principal component analysis (PCA) was conducted to quantify the coordination pattern of pitching movement. The results were as follows: (1) five position and two velocity parameters significantly differed among the age groups, and two position and one velocity parameters significantly differed between the high- and low-velocity groups. (2) The coordination patterns of pitching movement could be described using three components, of which the eigenvalues and contents varied according to age and velocity level. In conclusion, the senior and junior players showed greater elbow angular velocity, whereas the little players exhibited a wider shoulder angle only at the beginning of pitching. The players with high velocity exhibited higher trunk and shoulder rotation velocity. The variations among groups found using PCA and kinematics parameter analyses were consistent.     

安徽R&D投入产出水平的实证分析

在国内外的研究基础上,结合安徽特有的基本情况,建立了一套评价安徽省各市R&D投入产出综合水平指 标体系,运用主成分分析和聚类分析,客观的评价了安徽省各地市R&D投入产出水平。评价结果表明,“合芜蚌”试验 区引领带动着全省R&D投入产出水平,“皖江带”城市R&D投入产出水平两极分化严重,而“皖北”地区则有崛起的势 头,从而为各市提升R&D投入产出水平提供参考依据。     

现代西方思潮臆评

对待西方现代思潮应注意三条原则:第一,从人类认识发展和具体的社会历史背景考察其产生和发展的理由与根据,目的在于认识其现实性与非现实性;第二,既要"钻进去"又要"跳出来",将揭露其总体性的谬误和改造吸收其部分的合理性辩证统一起来,防止全盘否定论和全盘肯定论两种片面性;第三,具体问题具体分析,对西方思潮予以辩证的扬弃,批判的改造,以便为我所用。     

具有多连通分支的超越整函数的增长性

Let g and h be two transcendental entire functions. Suppose that the Fatou set F（goh） contains multiply connected components. In this article, we will consider the growth of the functions g and h.     

High-extensible scene graph framework based on component techniques

INTRODUCTION With the tremendous growth of the digital en- tertainment industry in the past decades, the scale of game scene is becoming more gigantic. To effectively manage and organize the massive data, game engine usually uses hierarchical scene graph. Many popular 3D modelling tools, such as Maya, 3D Studio Max, use scene graph to manage the scene content (Sowizral, 2000). 3D modelling software—Houdini directly edits scene graph to create and modify the virtual environment. Most v…     

B/S架构中基于HTML组件的WEB打印技术

一直以来B/S架构下的打印问题都是B/S系统开发中的难题,本文逐一对现有B/S架构打印方法进行了分析,针对它们的缺陷,提出丁一种基于HTML组件的更有效和更精确的打印方法,详细介绍了其原理,并给出了具体的实现方法,实践表明该方法使用效果良好.     

缓凝混凝土在轨道交通工程HPE桩基中的应用研究

在HPE桩基中施工时,必须保证钢柱能够顺利且准确的插入到混凝土桩基中,混凝土的缓凝时间能否符合要求关系到整个HPE工法能否顺利实施。利用特配的大流动超缓凝混凝土作为桩基材料,并应用于石家庄新客站地铁站紧邻石家庄新客站东侧的2号线车站,既保证了混凝土早期有较长的凝结时间,又保证了足够的后期强度,提高了整个HPE桩的施工质量。     

弧形混凝土结构温度应力计算研究

对弧形混凝土结构温度应力的计算研究表明，弧形结构的环向应力沿高度方向基本一致，可以简化为拱单元计算，拱单元的支座约束可以用“等效暗柱”来计算；结构两侧温差对弧形结构的环向应力的影响较轴线温差变化的影响更大，控制温度裂缝主要是控制结构物两侧的温差．通过设置滑动层，减小结构的抗侧移刚度。则弧形混凝土结构可以作无缝设计．     

古文英译的历程和前景

古文英译是翻译事业的组成部分。回顾古文英译的历程、总结经验、展望未来 ,以期有助于中西文化的交流和中西外事的交往。     

混凝土小型空心砌块建筑的应用

以粘土砖作为主要材料的建筑退出市场的日子日益临近。使用新型材料的新型建筑的推广与应用十分紧迫。虽然混凝土小型空心砌块建筑在建筑施工中也有使用,但由于种种原因应用并并不普及。天津“龙滨园住宅小区工程四号楼”通过设计、施工方案的不断改善,解决了小型空心砌块建筑的一般通病,达到了设计要求,使用状况良好。