人体重心动摇指标评价心理负荷强度的可能性

使用G - 550 0型测力台解析系统 ,分别在通常条件、竞争条件、观众条件的实验模拟环境下 ,对人体站立闭眼时的重心动摇进行测试 ,获得重心动摇距离、面积、速度等参数 ,探讨心理负荷强度与各参数之间的关系 ,筛选评定指标。发现心理负荷强度对人体的重心动摇产生影响 ,两者之间存在着线性相关 ,而且每个人的重心动摇还具有相对的常恒性。     

Reliability of power and velocity variables collected during the traditional and ballistic bench press exercise

This study aimed to examine the reliability of different power and velocity variables during the Smith machine bench press (BP) and bench press throw (BPT) exercises. Twenty-two healthy men conducted four testing sessions after a preliminary BP one-repetition maximum (1RM) test. In a counterbalanced order, participants performed two sessions of BP in one week and two sessions of BPT in another week. Mean propulsive power, peak power, mean propulsive velocity, and peak velocity at each tenth percentile (20–70% of 1RM) were recorded by a linear transducer. The within-participants coefficient of variation (CV) was higher for the load–power relationship compared to the load–velocity relationship in both the BP (5.3% vs. 4.1%; CV ratio = 1.29) and BPT (4.7% vs. 3.4%; CV ratio = 1.38). Mean propulsive variables showed lower reliability than peak variables in both the BP (5.4% vs. 4.0%, CV ratio = 1.35) and BPT (4.8% vs. 3.3%, CV ratio = 1.45). All variables were deemed reliable, with the peak velocity demonstrating the lowest within-participants CV. Based upon these findings, the peak velocity should be chosen for the accurate assessment of BP and BPT performance.     

列车荷载对下穿盾构隧道影响的模型试验

为研究地面线路运营对下穿盾构隧道结构的影响规律,基于相似比理论建立室内大型试验模型,模拟上部列车荷载作用下土层及其内部盾构隧道结构的受力变形过程,总结变形规律。结果表明,模型试验能够较好地反映外部荷载影响下土层以及内部盾构隧道结构的受力和变形特性;地表列车荷载在土层传递过程中,同一层面上沿地面线路方向的土压力大于两侧土压力,远离线路的地层受列车荷载影响相对较小,同一竖向截面土压力变化量由上至下逐渐减小,即外部荷载对浅层土的影响明显大于深层土;盾构隧道在地表列车行驶过程中,环向出现背车面受拉迎车面受压的受力特性,呈斜向压扁,纵向应变从中间交叉点向盾构隧道两侧逐渐减小,呈下凹压弯;盾构隧道埋深越小,受地表荷载影响越显著,增大一倍埋深对应纵向应变最大值减小约44.5%。     

文克尔地基薄板的瞬态响应分析

利用级数展开法和Laplace--Fourier变换推导了文克尔地基上无限长板在半波正弦瞬态荷载作用下位移和应力的解析解。计算和分析了板的位移响应情况,并和弹性地基静荷载情况的位移进行了比较,讨论了荷载作用时间、地基参数及板参数等对位移响应的影响。对路面设计、品质评价及破坏机理分析有重要意义。     

基于EUCALYPTUS的虚拟云改进研究

本文基于以往的研究,提出了通过虚拟相互通讯的进程,减少相互通讯的两个或多个任务的通讯时间。通过虚拟化通讯进程到一个工作站中,减少了进程间通讯开销和降低网络繁忙程度,从而降低网络通讯负载。由于虚拟化,增加了虚拟集团中的被虚拟化的硬件软件系统的资源的利用率,更加充分的利用这些结点的CPU的空闲计算能力,增加了系统中资源的利用率,并使系统的健壮性得到了提高。     

外语教学体验中心路由器的选购

为了合理选购路由器,介绍了对路由器的种类、硬件配置、功能、参数、协议、品牌、稳定性等诸多方面进行的系统研究。     

主应力轴旋转情况下土的各向异性理论研究进展

从理论方面,对国内外主应力轴旋转情况下土的各向异性研究进行了对比和总结,并提出了一些研究建议。指出在理论方面,应当对屈服面方程采用应力分量表示的模型在三维空间里进行屈服面性状的描述,同时考虑不同加载方向下屈服面的变化特性以及旋转硬化的问题,并应开展对加载方向变化时土体屈服面变化特性的实验研究及理论验证。     

电气化铁路接触网绝缘性能的实践研究

结合同煤集团四台沟电气化铁路110 kv牵引变电所及接触网供电设备故障跳闸率对煤矿电气化铁路定量装车点的接触网设备结构及污染情况进行了系统分析,研究出了提高重污区接触网设备绝缘性能的技改方法,并附注实践取得了良好的效果。     

Cognitive load and knowledge sharing in Learning Networks

Learning Networks (LNs) are online social networks designed to support nonformal learning; they are therefore particularly suitable for self-directed learners. In LNs, learners need to construct knowledge through knowledge sharing with other participants. However, without support, learners have to organize knowledge sharing themselves and this could induce extraneous cognitive load. When working on complex learning tasks, this organizing process could have a detrimental effect on knowledge construction. To optimize cognitive load, we propose using a peer support system that applies the mechanisms of peer tutoring to support knowledge sharing. Its mechanisms reduce, we argue, the extraneous load imposed by having to organize knowledge sharing as well as induce germane load by directing the freed-up cognitive capacity to processes that contribute to knowledge construction.