高速剪切轴向间隙的研究     

李耀辉  许春龙 《苏州市职业大学学报》2003,14(1):47-49

本针对剪切下料问题中存在的不足，从裂纹扩展的角度出发，结合断裂力学及塑性力学关于裂纹技术的相关理论，对剪切过程中影响断面质量的一个重要参数一轴向间隙进行分析，得出了高速剪切下合理轴向间隙的表这式。  相似文献   

体育院校乒乓球运动等级量化标准的探讨     

陈小华  黄莉芹 《武汉体育学院学报》2001,35(4):75-77,66

省市运动员通过参加大型比赛，在创造了优异的成绩后可批准相应的运动技术等级，体院大部分学生无此机会如何定运动等级?过去体院学生只要在学院比赛中取得相应的成绩即可(指二、三级)，而仅有的比赛并不能客观反映学生的实际水平。采取综合评定的方法．能更有效地促进学生自觉刻苦地训练，努力提高运动水平。在已达二、三级水平的学生中抽样测试，从8项指标中确定出技术和身体素质的达标基准线，具有较强的针对性和操作性，为今后综合评定运动员等级提供依据。  相似文献   

基于HHD测试的男子羽毛球运动员肩关节旋转特征分析     

王聪  秦学林 《福建体育科技》2017,36(1)

目的:通过观察男子羽毛球运动员肩关节旋转活动度及肌力的特征,为羽毛球运动员肩关节损伤的预防和康复提供参考。方法:以16名专业羽毛球男子运动员为受试对象,同时以9名普通男子为对照,使用手持式测力计(HHD)测定优势侧及非优势侧肩关节的旋内、旋外肌力;同时,测量其旋转被动活动度。结果:(1)男子羽毛球运动员肩关节旋外被动活动度大于旋内被动活动度。(2)男子羽毛球运动员肩关节优势侧旋内、旋外肌力均大于非优势侧,但旋外/旋内比例不存在双侧差异。结论:(1)男子羽毛球运动员肩关节旋转活动度存在双侧差异。(2)男子羽毛球运动员优势侧肩关节旋内、旋外肌力均大于非优势侧。  相似文献   

Guiding Low Spatial Ability Individuals through Visual Cueing: The Dual Importance of Where and When to Look     

Victoria A. Roach  Graham M. Fraser  James H. Kryklywy  Derek G.V. Mitchell  Timothy D. Wilson 《Anatomical sciences education》2019,12(1):32-42

Research suggests that spatial ability may predict success in complex disciplines including anatomy, where mastery requires a firm understanding of the intricate relationships occurring along the course of veins, arteries, and nerves, as they traverse through and around bones, muscles, and organs. Debate exists on the malleability of spatial ability, and some suggest that spatial ability can be enhanced through training. It is hypothesized that spatial ability can be trained in low-performing individuals through visual guidance. To address this, training was completed through a visual guidance protocol. This protocol was based on eye-movement patterns of high-performing individuals, collected via eye-tracking as they completed an Electronic Mental Rotations Test (EMRT). The effects of guidance were evaluated using 33 individuals with low mental rotation ability, in a counterbalanced crossover design. Individuals were placed in one of two treatment groups (late or early guidance) and completed both a guided, and an unguided EMRT. A third group (no guidance/control) completed two unguided EMRTs. All groups demonstrated an increase in EMRT scores on their second test (P < 0.001); however, an interaction was observed between treatment and test iteration (P = 0.024). The effect of guidance on scores was contingent on when the guidance was applied. When guidance was applied early, scores were significantly greater than expected (P = 0.028). These findings suggest that by guiding individuals with low mental rotation ability “where” to look early in training, better search approaches may be adopted, yielding improvements in spatial reasoning scores. It is proposed that visual guidance may be applied in spatial fields, such as STEMM (science, technology, engineering, mathematics and medicine), surgery, and anatomy to improve student's interpretation of visual content. Anat Sci Educ. © 2018 American Association of Anatomists.  相似文献   

Kinematic and kinetic analysis of overhand,sidearm and underhand lacrosse shot techniques     

Charles A. J. Macaulay  Pro Stergiou  Darren Stefanyshyn  Luciano Tomaghelli 《Journal of sports sciences》2017,35(23):2350-2356

Lacrosse requires the coordinated performance of many complex skills. One of these skills is shooting on the opponents’ net using one of three techniques: overhand, sidearm or underhand. The purpose of this study was to (i) determine which technique generated the highest ball velocity and greatest shot accuracy and (ii) identify kinematic and kinetic variables that contribute to a high velocity and high accuracy shot. Twelve elite male lacrosse players participated in this study. Kinematic data were sampled at 250 Hz, while two-dimensional force plates collected ground reaction force data (1000 Hz). Statistical analysis showed significantly greater ball velocity for the sidearm technique than overhand (P < 0.001) and underhand (P < 0.001) techniques. No statistical difference was found for shot accuracy (P > 0.05). Kinematic and kinetic variables were not significantly correlated to shot accuracy or velocity across all shot types; however, when analysed independently, the lead foot horizontal impulse showed a negative correlation with underhand ball velocity (P = 0.042). This study identifies the technique with the highest ball velocity, defines kinematic and kinetic predictors related to ball velocity and provides information to coaches and athletes concerned with improving lacrosse shot performance.  相似文献   

产教融合视阈下高职会计专业“会计工厂”的构建     

王广立 《广西职业技术学院学报》2019,(2):94-97

基于产教融合的视角,针对高职会计专业学生实习实践中存在的问题,以人工智能、大数据及财经职业教育的转型等对财务人员知识体系与能力发展提出的要求为导向,构建了“会计工厂”这一产教融合新模式。其构建路径包括:明晰构建目标,搭建“互联网+”会计学徒平台,将会计工作流程化,引入人工智能技术、影像识别技术、财经机器人等技术,实现工作智能化。“会计工厂”实行“每月轮行”“每周轮岗”的运作模式,具有职业场景真实,学习资源丰富,多行业、多岗位、多模式训练学生实操能力等特点,可以让学生们体验做“真账”、做“准员工”的感觉。  相似文献   

球坐标系中速度与加速度的转动参考系求法     

罗兴垅  罗颖 《赣南师范学院学报》2002,(3):28-30

应用转动参考系 ,给出了一种求解球坐标系中速度和加速度的简捷方法。该方法不仅图像清晰 ,简明直观 ,而且可应用到矢量力学教学中去  相似文献   

适用于数据分类的极限学习机优化算法     

吴亚榕  王欢  李键红 《教育技术导刊》2019,18(6):10-13

针对极限学习机参数优化问题,提出量子遗传算法优化极限学习机的方法（QGA-ELM）。在该方法中,对ELM的输入权值和隐含层阈值采用量子比特编码,并将其映射为QGA的染色体,QGA的适应度函数为对应ELM的分类精度;通过QGA的量子旋转门优化出输入权值与隐含层阈值,以此训练出分类精度更高的ELM,从而改善ELM的泛化性能。通过ELM和QGA-ELM对数据集的仿真结果对比表明,QGA-ELM有效地提升了ELM网络的分类精度。  相似文献   

矩阵乘法的来源和意义     

李长明 《贵州教育学院学报》2002,13(4):13-15

本文依据矩阵的乘法规则探寻出它的实际意义 ,再联系理论上的价值 ,揭示了矩阵乘法的必要性  相似文献   

直螺线管对称轴上的磁场     

王福谦 《长治学院学报》2003,20(5):26-28

文章以矩形螺线管轴线上的磁场分布特点为基础 ,将螺线管的对称截面按矩形进行分割 ,分析得出螺线管对称轴上磁场分布的一般规律。  相似文献