一种测量风传种子沉降速度系统的设计与实现     

王学进  李鑫  戴梅 《常熟理工学院学报》2014,(4):95-99

介绍了一种测量风传种子沉降速度系统的设计.系统采用MC9S12XS128单片机为主控芯片,利用两个线性CCD传感器分别采集种子下落过程中的视频信号,通过图像边缘检测算法精确捕捉种子下落过程中的始末两个时刻,利用加权算术平均法计算出种子沉降速度值,同时拟合出沉降高度与速度的曲线.实际测试表明,本系统具有测量精度高、抗干扰能力强、检测效率高、操作简单等优点.  相似文献   

自动扶梯控制柜检测台的设计与实现     

陈洁 《常熟理工学院学报》2014,(2):79-83

根据GB16899-2011《自动扶梯和自动人行道的制造与安装安全规范》的要求,分析了扶梯控制系统的组成结构,提出了一种检测自动扶梯控制柜功能的方案,给出了电路原理、产生速度脉冲的方法,并列出了材料清单。  相似文献   

Relative Age Effect,Biological Maturation,and Coaches’ Efficacy Expectations in Young Male Soccer Players     

Iván Peña-González  Jaime Fernández-Fernández  Manuel Moya-Ramón  Eduardo Cervelló 《Research quarterly for exercise and sport》2018,89(3):373-379

Purpose: The talent identification and selection process in young male soccer players is mainly focused on anthropometrics and physical performance, but social factors are also considered in this process. The purpose of this study was to test the existence of the relative age effect and its possible influence on anthropometrics and physical performance and to analyze coaches’ efficacy expectations. Method: Data for 564 young male soccer players (M_age = 13.7 ± 1.5 years; M_weight = 53.7 ± 11.6 kg; M_height = 160.2 ± 11.6 cm) included their birth quartile, maturity status, anthropometrics, a physical test battery, and coaches’ efficacy expectations. Results: Early-born players were overrepresented (p < .05). Early-born players were not statistically taller, heavier, or better at physical performance (p > .05) when maturation and chronological age were controlled as confounding factors. However, coaches expected more from early-born players (p < .05), and the inferential analysis showed likely to very likely worthwhile differences between the coaches’ expectations for players born in the first quartile of the year and those born in the fourth quartile of the year. Conclusions: Anthropometrical and physical performance variables were not affected by birth quartile, and coaches’ efficacy expectations were related to the relative age effect.  相似文献   

煤气洗涤水的治理研究   总被引：1，自引：0，他引：1  

陶静 《鞍山师范学院学报》1999,(3)

采用氧化 絮凝方法对煤气洗涤水进行了研究 .通过实验选择二氧化氯为氧化剂 ,聚丙烯酰胺和石灰为混凝剂 ,并综合考虑处理效果和药剂费用等各方面因素 ,通过正交实验确定了主要技术参数 .  相似文献   

棒球投手投球动作的运动生物力学研究综述     

马秀杰  韩志磊  梁占锁 《中国体育科技》2010,46(2)

通过对近20多年来国内、外学者对棒球投手的运动生物力学研究成果进行整理分析研究,研究认为,目前对棒球投手的生物力学研究主要运用高速摄影、等速肌力测试、肌电图、三维测力台等科研手段,从运动学、动力学、肌电学方面对影响棒球投球动作质量及投球速度的关键部位和因素进行了深入研究,并在此基础上对优化投球动作以减少运动损伤等方面进行了探讨.  相似文献   

短跑支撑阶段运动生物力学分析          下载免费PDF全文

施宝兴 《体育科研》2010,31(6):40-43

采用测力、高速录像及特殊的数据平滑处理方法研究短跑运动员途中跑技术的运动学和动力学特征,进行田径技术原理的探索。结果表明,支撑时期可以分为着地阶段和蹬伸阶段,蹬伸阶段可分前蹬,后蹬前段,后蹬后段。途中跑前蹬段是人体重心垂直方向向上加速的重要时刻,前蹬时下肢一定程度的垂直加速用力虽影响水平速度,但对提高垂直速度有积极意义,前蹬和后蹬前段是身体重心垂直向上加速运动的阶段。着地缓冲后的前蹬用力也是实现良好成绩的技术之一。途中跑着地和前蹬阶段失去的水平速度损失完全可以从后蹬中得到补充。着地点过近对前支撑阶段获得重要的垂直速度不利,支撑阶段离地前的20ms身体重心速度已经开始下降。  相似文献