Reliabilities of leg and vertical stiffness during treadmill running

The aim of this study was to determine the intra-participant variabilities (i.e. intra-day and inter-day reliabilities) in leg and vertical stiffness, as well as related kinematic parameters, during treadmill running using the sine-wave method. Twenty-two healthy men ran on a treadmill at 4.44 m/s, and the flight and contact times were measured with a high-speed video camera. Three 30-s running bouts with 2-min inter-bout rests were performed to examine the intra-day reliability, and single 30-s running bouts on three separate days with 24- to 48-h inter-bout intervals were performed to examine the inter-day reliability. The reliability statistics included repeated-measure analyses of variance, average inter-trial correlations, intra-class correlation coefficients (ICCs), Cronbach's α reliability coefficient, and the coefficient of variation. Both leg and vertical stiffness produced high ICCs within 0.972 and 0.982, respectively, and between 0.922 and 0.873 days, respectively. High values were also observed for all of the reliability coefficients. Similar results were found regarding contact time, flight time, step length, and step rate. It was concluded that the measurements of leg and vertical stiffness, as well as related kinematic parameters, obtained using the sine-wave method during treadmill running at 4.44 m/s, were highly reliable, both within and across days.     

理想第二类超导体的临界场

借助Ｇｉｎｚｂｕｒｇ－Ｌａｕｄａｕ理论，阐述了理想第二类超导体处于混合态的临界场，并得出下临界场Ｈｃ１与穿透深度λ、相干长度ξ有关，上临界场Ｈｃ２与参量α有关的结论。     

步长步频及其派生指标在短跑训练实践中的运用

恰当地运用步长、步频及其派生指标对不同的个体进行合理、科学的比较,是对运动员的速度能力作出客观、准确的判断和进行有针对的、卓有成效的速度训练的前提和保证。本文结合运动训练实例,对不同指标的运用差别进行了分析,并提出了应注意的问题。     

大同市地裂缝分布及防灾对策

地裂缝是地下断裂构造在地表土层形成的痕迹,地裂缝灾害造成严重经济损失和社会影响。本文对大同市地裂缝的现状、危害情况、基本特征及成因进行了分析,并提出防灾对策。     

电沉积法修复混凝土裂缝的初步进展

电沉积法是通过电解作用把某些物质沉积在电极的表面，利用这一方法可以愈合混凝土的裂缝，它具有独特的优势，特别适用于传统的修复技术难以奏效的海工混凝土结构。本文对国内外利用电沉积法修复混凝土裂缝的研究进行了评述，并介绍了近年来在国家自然科学基金资助下我们在这一领域取得的最新研究成果。     

泰国留学生三组普通话辅音的实验研究

以两名汉语普通话水平为初、中级的泰国留学生作为研究对象,以声学实验为手段,通过对比分析泰国学生普通话三组塞擦音、擦音与中国发音人之间的差异,寻找泰国学生二语习得过程中语音方面的偏误和障碍,最后针对这些偏误和障碍提出教学对策。经过实验分析发现,泰国留学生在汉语普通话的音节时长、声母时长方面与中国发音人存在差异;另外,泰国学生在发这三组音时,舌位均较前。     

孔隙分布不均匀性对渗透率影响的MRTLBM法研究

孔隙率与渗透率是多孔介质非常重要的属性参数,采用MRT LBM研究孔隙率损失与渗透率损失相关性以及同孔隙率异构孔隙对渗透率特性的影响。结果表明：当存在使孔隙率均匀变小的沉积、沉降或结焦等因素时,渗透率损失率是孔隙率损失率的2倍左右;同孔隙率异构多孔体中,渗透率有巨大差异;同孔隙率异构多孔体中最大孔喉最小孔喉比越大渗透率越小;同孔隙率多孔体中迂曲度越大渗透率越小。     

潜艇远航中艇员疲劳状况研究

通过对艇员疲劳自觉症状的调查,研究分析了远航中艇员疲劳状况的发生及其影响因素。阐述了艇员疲劳对潜艇航行安全的影响,并提出了改进措施与应对手段。     

基于摄动法的裂纹梁振动模态研究

为评估裂纹损伤发生的位置及损伤程度,基于改进的裂纹损伤模型,应用摄动法研究裂纹梁的振动模态变化特性.建立由一阶和二阶摄动量表示的EulerBernoulli裂纹梁振动特征方程,推导出裂纹梁振动特征值和模态振型的一阶和二阶摄动解析表达式,并通过与损伤悬臂梁实验结果对比,验证该方法的可靠性.     

论文被引的文本因素分析：多学科视角

文献长度、参考文献数量是否影响论文被引频次,不同学科有不同的检验结果。网络环境下,题名字数、关键词个数是否对论文被引具有显著影响,尚未见文献报道。通过对来自6个学科的455篇论文被引的文本因素进行分析,发现：①关键词个数对文献被引存在明显的影响;②参考文献数量对英文语种文献的被引确实存在显著影响,但对中文语种文献被引的影响却不能通过显著性检验;③多学科背景下,文献篇幅长短及题名字数多少对文献被引没有显著影响;④存在“中国学者所发表的英文论文,篇幅越长越有可能不被引用”的现象。