平直界面一维晶体生长问题的相似解     

刘竞 《石家庄职业技术学院学报》2005,17(6):1-3

对于平直界面下由过冷边界开始的熔体的一维凝固过程，考虑液态中远场温度高于凝固温度，而底板温度低于凝固温度，利用相似性解法分别求解固液态温度，分析其结果，说明由低温区长入高温区的界面总是稳定的，从而更加完善了一维晶体生长理论．  相似文献   

A national sports institute as a learning culture     

Jessica Lee  Nathan Price 《Physical Education & Sport Pedagogy》2016,21(1):10-23

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How does visual manipulation affect obstacle avoidance strategies used by athletes?     

M. P. Bijman  J. J. Fisher 《Journal of sports sciences》2016,34(10):915-922

Research examining our ability to avoid obstacles in our path has stressed the importance of visual input. The aim of this study was to determine if athletes playing varsity-level field sports, who rely on visual input to guide motor behaviour, are more able to guide their foot over obstacles compared to recreational individuals. While wearing kinematic markers, eight varsity athletes and eight age-matched controls (aged 18–25) walked along a walkway and stepped over stationary obstacles (180° motion arc). Visual input was manipulated using PLATO visual goggles three or two steps pre-obstacle crossing and compared to trials where vision was given throughout. A main effect between groups for peak trail toe elevation was shown with greater values generated by the controls for all crossing conditions during full vision trials only. This may be interpreted as athletes not perceiving this obstacle as an increased threat to their postural stability. Collectively, findings suggest the athletic group is able to transfer their abilities to non-specific conditions during full vision trials; however, varsity-level athletes were equally reliant on visual cues for these visually guided stepping tasks as their performance was similar to the controls when vision is removed.  相似文献   

Quality of life perception of basketball master athletes: association with physical activity level and sports injuries     

Natália Boneti Moreira  Oldemar Mazzardo  Gislaine Cristina Vagetti  Valdomiro De Oliveira  Wagner De Campos 《Journal of sports sciences》2016,34(10):988-996

This study aimed to verify the prevalence and characteristics of sports injuries (SI) and determine the association between the physical activity level (PA) and SI with perception of health-related quality of life (HRQoL) in Brazilian basketball master athletes. A cross-sectional study was conducted with 410 male master athletes, between 35 and 85 years of age (mean 52.26, SD ±11.83). The HRQoL was assessed using the Medical Outcomes Study – Short Form-36. The PA was evaluated using the International Physical Activity Questionnaire. Information regarding SI was collected using the Reported Morbidity Survey. Poisson regression, as estimated by the prevalence ratio (PR), was used as a measure of the association of PA and SI with HRQoL. The majority of athletes showed a high SI prevalence (58.3%) and reported one injury (67.8%) that occurred during training (61.1%) and primarily affected a lower limb (74.6%). The adjusted regression models showed a positive association of PA with the Functional Capacity (PR = 1.46, 95% confidence interval [CI] = 1.12–1.90) and Physical Component (PR = 1.32, 95% CI = 1.03–1.70) of HRQoL. Furthermore, the SI were negatively associated with HRQoL in Functional Capacity (PR = 1.85, 95% CI = 1.51–2.27), Physical Aspects (PR = 3.99, 95% CI = 3.08–5.18), Pain (PR = 1.65, 95% CI = 1.26–2.16), Social Functioning (PR = 1.79, 95% CI = 1.41–2.27), Emotional Aspects (PR = 4.40, 95% CI = 3.35–5.78), Mental Health domains (PR = 1.37, 95% CI = 1.06–1.68), Physical Component (PR = 2.35, 95% CI = 1.90–2.90) and Mental Component (PR = 2.65, 95% CI = 2.14–3.29). These results highlighted that master athletes showed a high SI prevalence, primarily in the lower limbs. PA positively correlates with the physical HRQoL domain, whereas SI may decrease the HRQoL levels of both physical and mental domains.  相似文献   

The key to success in elite athletes? Explicit and implicit motor learning in youth elite and non-elite soccer players     

L. Verburgh  E. J. A. Scherder  P. A. M. van Lange  J. Oosterlaan 《Journal of sports sciences》2016,34(18):1782-1790

In sports, fast and accurate execution of movements is required. It has been shown that implicitly learned movements might be less vulnerable than explicitly learned movements to stressful and fast changing circumstances that exist at the elite sports level. The present study provides insight in explicit and implicit motor learning in youth soccer players with different expertise levels. Twenty-seven youth elite soccer players and 25 non-elite soccer players (aged 10–12) performed a serial reaction time task (SRTT). In the SRTT, one of the sequences must be learned explicitly, the other was implicitly learned. No main effect of group was found for implicit and explicit learning on mean reaction time (MRT) and accuracy. However, for MRT, an interaction was found between learning condition, learning phase and group. Analyses showed no group effects for the explicit learning condition, but youth elite soccer players showed better learning in the implicit learning condition. In particular, during implicit motor learning youth elite soccer showed faster MRTs in the early learning phase and earlier reached asymptote performance in terms of MRT. Present findings may be important for sports because children with superior implicit learning abilities in early learning phases may be able to learn more (durable) motor skills in a shorter time period as compared to other children.  相似文献   

运动员感恩的价值及其培养策略分析     

董良山  王斌  叶绿  卜姝 《湖北体育科技》2016,(8):734-737

运动员感恩教育是指运动队的管理者或者教练员根据运动员的个性特点,在训练和比赛的过程中运用一定的方法和手段,创造一定的感恩氛围,激发和引导运动员对知恩、感恩、报恩、施恩的价值认同,并付诸实践的道德教育过程。运动员感恩的价值主要体现在增加运动员的心理应对资源;促进运动员行为的积极变化;建立和维持运动员的人际关系网络。对运动员进行感恩教育的培养策略可以从以下3个方面进行:营造良好的感恩教育环境;创新感恩教育的方式、方法;提升感恩认知和行为。  相似文献   

中国皮划艇国家二队功能动作筛查的应用研究     

李琴  高潼阳  贾昊哲  孔运峰  余银 《湖北体育科技》2016,(11):997-1000

运用文献资料法、测试法、问卷调查法、专家访谈法和数理统计法对国家皮划艇青年队进行功能动作筛查测试,根据测试结果为备战2020年奥运会提供数据及理论的支持。通过研究发现:划艇运动员的总分情况整体优于皮艇运动员;大部分运动员髋、膝、踝三关节在单一的运动平面中具有较好的协调和稳定性,但在两个以上的运动平面中完成动作的稳定和控制能力有待提高;运动员的髋关节、肩关节及股四头肌柔韧性存在不平衡现象,左侧链与右侧链在多运动平面中协调稳定性也存在不平衡现象;运动员的损伤率较高,且损伤的主要部位是肩和腰。  相似文献   

运用Excel解决高校田径运动会秩序册编排中的问题   总被引：1，自引：0，他引：1  

籍建东 《滨州学院学报》2008,24(3)

运用Excel"筛选"、"数据透视表"等功能,解决运动员号码生成、运动项目及各项目运动员人数的统计与整理等问题.通过此方法可以实现秩序册的规范和美观,提高高校田径运动会秩序册编排的效率.  相似文献   

基于Pro/E的直齿锥齿轮Program参数化造型     

Pei Zhiming) Xu Juan) Lv Huiming) 《石家庄铁路工程职业技术学院学报》2007,(3)

介绍Pro/Engineer的Program参数化造型方法及其程序结构,并且以直齿锥齿轮为实例,详细地介绍Program参数化造型的实现过程。为同类产品实现参数化造型,减少重复劳动,提高设计效率提供一种适用、有效的方法。  相似文献   

利用混沌吸引子的不稳定周期轨道的保密通信     

杨凤霞 《沧州师专学报》2003,19(1):46-48

混沌系统的特性可用其混沌吸引子在相空间中的轨迹来表征。大量的研究表明、一个混沌吸引子是由无穷多个不稳定的周期轨道所组成的。通过对不稳定周期轨道的幅度或相位进行调制，则可实现对信息的保密传输。据此，在一个混沌时间序列的每一个不稳定周期轨道中、通过调制不同的信息流，就可以用单一的混沌时间序列来传输多路信息。  相似文献