基于Matlab的单闭环直流调速系统仿真实验设计

分析Matlab/Simulink仿真技术在转速单闭环直流调速系统中的应用.考虑了转速有静差和无静差两种情况,采用面向电气原理结构图的仿真方法建立仿真模型;给出主电路和控制电路的参数设置方法,同时改变转速调节器的参数设置,对单闭环直流调速系统的调速性能进行仿真实验分析,并给出直流电动机的转速和电枢电流仿真波形.实验结果表明,单闭环直流调速系统的调速性能仿真结果与理论推导的调速性能一致,对实验教学有一定的指导意义.     

动作技能学习中的个体差异研究综述

以个体差异的研究现状为基础,归纳总结了个体差异在动作技能学习中所涉及到的主要因素变量,旨在为未来动作技能教学和学习提供借鉴。     

任务性质、观察学习和身体练习比例对运动技能学习的影响

观察使用计算机追踪任务探讨任务性质、观察学习和身体练习比例对运动技能学习的影响。72名受试划分为开放性任务学习组和封闭性任务学习组,然后再根据观察学习+身体练习比例将受试随机分为25%观察学习+75%身体练习组、50%观察学习+50%身体练习组、以及75%观察学习+25%身体练习组,进行为期3 d的计算机追踪任务学习。第3 d学习结束后,对所有受试进行即刻测试2、4 h后保持测试和迁移测试。结果显示:对于封闭性任务技能学习而言,50%观察学习+50%身体练习的比例所获得的学习效果好于25%观察学习+75%身体练习的比例和75%观察学习+25%身体练习的比例;对于开放性任务技能学习而言,25%观察学习+75%身体练习的比例所获得的学习效果好于75%观察学习+25%身体练习的比例;使用相同比例条件下,封闭性任务技能的学习效果好于开放性任务技能。     

基于磁共振成像的优秀排球运动员大脑结构可塑性研究

目的:采用磁共振成像技术(MRI),对优秀排球运动员和普通大学生的大脑结构进行研究,探讨多年的动作技能学习和运动训练对优秀排球运动员大脑结构产生的可塑性变化.方法:采用Siemens Magnetom Tri0 3.0T磁共振成像系统,对20名优秀排球运动员和20名普通大学生安静状态下进行全脑MRI扫描.数据通过头动校正、空间标准化、高斯平滑等预处理后,采用SPM 8分析组间全脑灰质和白质体积的差异,采用最优化的VBM获取高分辨率的全脑图像.将Freesurfer测量出来的皮层厚度数据进行组间方差分析,找出组间皮层厚度存在显著差异的区域.结果:运动员在大脑右半球枕叶外侧上的灰质体积要显著高于普通大学生;大脑右半球枕叶外侧上的皮层厚度要显著厚于普通大学生.出现显著性差异的主要脑区部位是负责视觉加工的脑区.结论:优秀排球运动员多年的动作技能学习和运动训练能够对其大脑右半球负责视觉信息加工的枕叶脑区结构产生可塑性变化.     

浅析篮球胯下变向运球技术的动作技巧及身体用力特点

运用文献资料法、动作技术分析法,从脚步移动、控制支配球和手、脚、身体的协调配合三个方面对胯下变向运球技术进行分析,并提出胯下变向运球技术在以上三个方面练习时需要掌握的技巧和身体的用力方法。     

Beam-stabilized optical switch using a voice-coil motor actuator

This paper presents the design, analysis, and implementation of a beam-stabilized optical switch using a voice-coil motor actuator. A closed-loop control system using a proportional-integral-derivative (PID) controller is developed to stabilize the beam at the desired angle to maximize the optical power detected by a photodiode. Experimental results show a good performance with 17 ms switching speed and a maximum overshoot of only 3%.     

步进电机加减速控制

应用 8 0C5 1单片机控制步进电机的加速、减速 ,并指出其不足之处。     

The improvement in mental rotation performance in primary school-aged children after a two-week motor-training

The present study investigated the influence of motor training on mental rotation performance in children aged between 8 and 10 years Two groups of 42 children each solved a psychometric mental rotation task with three-dimensional block figures. After the initial test, one group received two weeks of specific coordinative motor training every school day for 20?min, while the other group did not receive any additional training. At the end of the training period, all children solved the mental rotation task again. The results show that both groups improved their performance from the pre- to the post-test; however, the improvement for the training group was higher than for the non-training group. This study shows the influence of motor training on mental rotation performance.     

基于Ackermann模型的轮毂电机四轮独立驱动电动汽车电子差速转向控制研究

对四轮独立驱动、四轮独立转向的电动车进行了电子差速控制转向研究,以电控方式控制各个车轮的转速,使车轮以不同速度转动,满足Ackermann转向模型条件,使电动车实现差速转向控制．针对左右前轮转向由各轮转向电机独立控制、左前轮转向不控制、右前轮转向不控制、左右前轮转向都不控制4种转向电机控制方案,进行整车蛇形行驶试验对比,旨在探索是否能够简化转向机构而实现电动汽车转向控制的可行性．     

The validity of computerized visual motor integration assessment using Chinese basic strokes

ABSTRACT

The purpose of this study is to explore the validity of the assessment tool. The purposive sampling method is applied in this research on a total of 551 preschool children between 4 and 6 years old. Their ages range from 46 to 81 months, with an average age of 63.9 months (SD?=?7.58). The assessment tool used in this research is the “Computerized Visual Motor Integration Assessment Tool Using Chinese Basic Strokes”. The multivariate logistic regression analysis was used to automatically determine children’s writing classification. The findings suggest that the assessment tool developed has good validity in terms of sensitivity, specificity and the accuracy. This tool is recommended for use in the diagnosis of Chinese visual motor integration issues for preschoolers, so that their potential writing difficulties may be detected early, and the goal of early intervention may be achieved.