表面肌电图在人体运动研究中的应用

肌肉运动时会有微小的生物电变化，表面肌电图作为一种无创的检测方法来检测这种生物电变化。运动时肌电图的振幅、频率等指标均会产生相应的变化，而且这些变化与运动方式、运动状态、肌肉疲劳密切相关。     

咖啡与运动

1995年6月,国务院颁布《全民健身计划纲要》,随着此纲要的颁布,当今人们对体育运动是越来越重视。然而运动必将产生疲劳,随着自由基理论引入运动医学领域之后,运动与自由基已成为人们关注的课题。最近一些科学研究也恰巧证明了咖啡有利于清除自由基。同时为竞技运动员的疲劳恢复开辟了新的出路。本文就咖啡与运动性疲劳和机体细胞的损伤这一问题进行简要综述。     

体育运动训练竞赛中疲劳类型及其解决途径

近年来,体育运动愈来愈受到人们的关注和青睐,在体育运动训练与竞赛中产生运动疲劳是身体运动到一定程度从而引起组织器官机能下降的一种正常生理现象,然而当运动负荷超过人体的机能承载能力时,就会让人呼吸变得急促、肌肉酸痛、反应迟钝,必须经过一段时间恢复才能继续运动,所以如何消除疲劳感是体育训练中需要重点解决的问题。基于此,该文对体育运动训练中常见的疲劳类型和判断方法进行了分析,并提出了相应的解决措施,帮助消除疲劳感和提高身体素质。     

The relationship between inertial measurement unit-derived ‘force signatures’ and ground reaction forces during cricket pace bowling

Abstract

This study assessed the reliability and validity of segment measured accelerations in comparison to front foot contact (FFC) ground reaction force (GRF) during the delivery stride for cricket pace bowlers. Eleven recreational bowlers completed a 30-delivery bowling spell. Trunk- and tibia-mounted inertial measurement units (IMUs) were used to measure accelerations, converted to force, for comparisons to force plate GRF discrete measures. These measures included peak force, impulse and the continuous force–time curve in the vertical and braking (horizontal) planes. Reliability and validity was determined by intra-class correlation coefficients (ICC), coefficient of variation (CV), Bland–Altman plots, paired sample t-tests, Pearson’s correlation and one-dimensional (1D) statistical parametrical mapping (SPM). All ICC (0.90–0.98) and CV (4.23–7.41%) were acceptable, except for tibia-mounted IMU braking peak force (CV = 12.44%) and impulse (CV = 18.17%) and trunk vertical impulse (CV = 17.93%). Bland–Altman plots revealed wide limits of agreement between discrete IMU force signatures and force plate GRF. The 1D SPM outlined numerous significant (p < 0.01) differences between trunk- and tibia-located IMU-derived measures and force plate GRF traces in vertical and braking (horizontal) planes. The trunk- and tibia-mounted IMUs appeared to not represent the GRF experienced during pace bowling FFC when compared to a gold-standard force plate.     

Numerical Simulation of Dynamic Response of an Existing Subway Station Subjected to Internal Blast Loading

In order to design and retrofit a subway station to resist an internal blast,the distribution of blast loading and its effects on structures should be investigated firstly.In this paper,the behavior of a typical subway station subjected to different internal blast Ioadings was analyzed.It briefly introduced the geometric characteristics and material constitutive model of an existing two-layer and three-span frame subway station.Then three cases of different explosive charges were considered to analyze the dynamic responses of the structure.Finally,the maximum principal stress,displacement and velocity of the columns in the three cases were obtained and discussed.It concluded that the responses of the columns are sensitive to the charge of explosive and the distance from the detonation.It's also found that the stairs between the two layers have significant effects on the distribution of the maximum principal stress of the columns in the upper layer.The explicit dynamic nonlinear finite element software-ANSYS/LS-DYNA was used in this study.     

非稳态蠕变二维裂纹尖端场强近似分析

从幂律蠕变材料静态裂纹体在时间相关比例加载条件下的应力应变场分析出发，建立了弹性—幂律蠕变材料裂纹体在时间相关比例加载条件下的瞬态Ｊ（ｔ）积分和Ｃ（ｔ）积分的估算公式，并给出了载荷恒定和加载点位移恒定这两种特殊情况下的Ｊ（ｔ）积分和Ｃ（ｔ）积分的解析表达式．作为实例，计算分析了紧凑拉伸试样等几种典型裂纹构形在加载点位移恒定情况下的Ｊ（ｔ）积分和Ｃ（ｔ）积分，并与有限元解进行了比较．     

零散货物装载的一种快速算法

研究了零散货物的装载问题。根据待装货物体积、重量与货车客积、载重的相对关系，将货物分为两类。对于不同货物类型的单车装载问题，优先考虑其主要约束目标，而对其他目标则适时调整。对于货物足够多的多车装载问题，关键是按照货物的类型确定不同的装车顺序。对于货车足够多的多车装载问题，则利用上次循环得到的解，对下一次的装车次序进行调整，使解不断趋于优化。     

Optimal sizing of piezo-actuators for minimum-deflection design of frames under uncertain loads

Optimal piezo-actuator sizes and locations for a frame structure under bending load uncertainty are determined with the objective of minimizing the deflection under worst case of loading. The bending moments generated by the piezo-actuators are used for deflection control, i.e., to minimize the maximum deflection. The frame is subjected to a tip load which lies in an uncertainty domain with regard to its magnitude and direction. The specific uncertain loading studied in the present paper involves a load of given magnitude but of unknown direction, which should be determined to produce the highest deflection. The worst case of loading depends on the size and location of the actuators leading to a nested problem of optimization (design) and anti-optimization (uncertainty problem). Results are given for deterministic and uncertain loading conditions.     

涡河亳州境内水污染状况分析

在涡河亳州境内水质实测资料的基础上,分析区域内的亳州、涡阳、蒙城的四个水质监测断面水污染现状,并将三市县各排污口污染物总排放量采用等标污染负荷法进行评价,分析了涡河水污染特征,确定其主要污染物和主要污染源。在此分析基础上,结合分析区域的社会经济和自然环境条件,对污染原因进行探讨分析,并相应的提出有针对的防治措施和具体要求。     

狗骨式刚性连接的滞回性能试验研究

通过对循环荷载作用下的狗骨式刚性连接节点的试验研究，分析了狗骨式刚性连接的滞回性能．试验结果表明：狗骨式刚性连接具有良好的延性和耗能能力，节点的转角都超过了0．03rad；焊缝强度和梁翼缘的削弱程度是影响节点滞回性能和极限承载力的决定因素．最后，根据试验结果提出了此类连接的设计和施工建议．