基于PLC的交通绿波带系统设计

本文以避免城市内交通拥挤和车辆堵塞为目的，提出了基于PLC的交通绿菠带设计思想，阐述了交通绿菠带的设计原理，论述了应用PLC实现交通绿菠带的可行性和优越性。并以邢台市中兴大街为例，采用网络PLC的控制方式，从PLC的选型、硬件设计、软件设计三个方面进行了交通绿菠带的系统设计。可供市内交通管理部门和对PLC应用感兴趣的读者参考。     

Experimental Investigation into Magnetortheological Damper Subjected to Impact Loads

A good mechanical model of magnetorheological damper (MRD) is essential to predict the shock isolation performance of MRD in numerical simulation.But at present,the mechanical models of MRD were all derived from the experiment subjected to harmonic vibration loads.In this paper,a commercial MRD (type RD-1005-3) manufactured by Lord Corporation was studied experimentally in order to investigate its isolation performance under the impact loads.A new mechanical model of MRD was proposed according to the data obtained by impact test.A good agreement between the numerical results and test data was observed,which showed that the model was good to simulate the dynamic properties of MRD under impact loads.It is also demonstrated that MRD can improve the acceleration and displacement response of the structure obviously under impact loads.     

体育教学中运动负荷规律的科学运用

在体育教学中,学生生理和心理方面在不同程度上受到刺激,承受一定的负荷,校长时间的刺激和负荷,容易引起学生生理和心理两个方面产生疲劳,而疲劳的产生和积累．又会直接影响学生的学习效果。所以如何掌握和运用好运动负荷,是上好一堂体育课的关键。研究体育课的负荷,对于保证体育课的顺利,促进学生命身心健康发展,提高教学质量等．都具有重要意义。笔者在长期的中学体育教学中．根据多年教学实践,就“运动贞行规律的科学运用”进行探讨研究．以促进体育教学质量的进一步提高。     

Biomechanical analysis of the “waiter’s serve” on upper limb loads in young elite tennis players

Waiter’s serve (WS) is a specific tennis serve posture frequently observed in young players, and commonly considered as a technical error by tennis coaches. However, biomechanical impact of WS is unknown. The aims of this study were to identify the potential consequences of WS in young elite players relating to performance and injury risk, and to explain the kinematic causes of WS. Serve of 18 male junior elite players (Top 10 national French ranking, aged 12–15 years) was captured with a 20 camera, 200?Hz VICON MX motion analysis system. Depending on their serve technique, the players were divided into two groups (WS versus Normal Serve [NS]) by experienced coaches. Injury data were collected for each player during a 12-month-period following the motion capture. Normalized peak kinetic values of the dominant arm were calculated using inverse dynamics. In order to explain WS posture, upper limb kinematics were calculated during the cocking and the acceleration phases of the serve. Shoulder internal rotation torque, wrist proximal and anterior forces (P?P?P?相似文献   

广东女子曲棍球队运动员赛前机能水平监控的研究

对广东女子曲棍球运动员在2005年全国冠军杯赛前进行机能评定和疲劳监控,结果显示：在赛前训练期间,运动员的机能状况总体较好,但个别运动员的体质状况和运动负荷适应情况及恢复情况波动较大,有待随时进行调整,以适应更大负荷的训练。     

不同负荷负重游泳训练对大鼠整体机能和血清T、C、IGF-1的影响

以强度训练为特点,力图建立符合实际训练负荷的训练模型,探讨负重游泳训练对大鼠机体整体机能表现和合成分解代谢平衡的关系.训练前后所有大鼠进行负重爬杆测试.结果发现:1) 15%G组大鼠负荷过大,明显不能适应训练.2) 负重游泳训练使大鼠力量素质提高,而且在适宜的范围内,训练负荷越大,力量素质增长越明显,而15%G组大鼠造成力量素质的相对下降.3) 在适宜范围内,大鼠合成激素水平(血睾酮和血清IGF-Ⅰ)的提升随着训练负荷的增大而变得更明显,但15%G组大鼠合成激素水平的相对下降.而大鼠血清皮质酮的升高随着训练负荷的增大而变得更明显,使15%G组大鼠合成激素与分解代谢激素比值较其它运动各组为低.表明:适宜的负重游泳训练使机体代谢状态以合成代谢为主,整体机能提高;过度的负重游泳训练使机体代谢状态以合成代谢为主,整体机能下降.     

国家助学贷款面临的问题及其应对策略

国家助学贷款是党中央、国务院为实施科教兴国战略,加速人才培养,特别是使经济较困难的优秀青年得以深造的重大决策,作为高等教育经费补偿的重要形式,受到了全社会的关注,但在实施中并未达到顶期的效果。本文就发展国家助学贷款中出现的问题进行了初步探讨,对其成因做了深入的分析,最后提出了对高校学生加强诚信教育、建立全国个人信用信息征信系统、制订相关的法律和法规等对策来推动国家助学贷款良性发展。     

现代竞技运动阶段性训练计划的多元性特点的比较

阶段训练计划联结年度训练计划和多年训练计划,下联结周的训练计划和课的训练计划,起着桥梁作用,主要从阶段训练计划的4项特点比较,总结一些共性特点,提高训练的科学性、计划性,为提高我国竞技水平服务.     

馆藏录音磁带的数字化及网络下载服务器的架设

在传统方式下,馆藏录音磁带的保存、使用和流通在技术及管理方面存在着许多困难.本文主要从数字技术和计算机网络技术着手,探讨如何运用数字音频技术解决馆藏磁带的保存问题,以及利用计算机网络技术向读者提供数字化音频文件的流通服务.     

高温超导带材及线圈的交流损耗（英文）

本文将描述超导体各向异性的有效质量理论,即各向异性Ginzburg—Landau 理论（G—L理论）,与临界态模型(CS模型)相结合,建立了高温超导带材的交流损耗与临界电流的各向异性理论模型; 利用不可逆应变的定义,给出了临界电流与应变的关系,并利用临界电流与应变的关系及Norris方程,导出了高温超导带材的交流损耗与应变的关系; 利用所建立的交流损耗与临界电流的各向异性理论公式,建立了依据超导短样带材的特性(临界电流,交流损耗）,计算高温超导线圈交流损耗的数值计算模型.