鸭河口水库浮游动物群落及其水质评价

为了掌握鸭河口水库水体的营养现状,为南阳市饮用水源的水质管理及供水处理提供理论指导,于2013年11月对鸭河口水库浮游动物和水质理化指标进行监测.按浮游动物水样采集标准方法采样,采用污水生物系统法和营养状态指数法对水源区进行富营养化程度评价.浮游动物有27种(隶属19科21属),其中枝角类和轮虫最多,均为9种,桡足类6种,原生动物3种,仅检测到1种β-中污(βm)指示种;浮游动物平均密度为2324 ind./L;水质理化监测指标中总氮超标,其他符合地表水Ⅰ类标准;库体水质营养状态指数为48.13.结合浮游动物群落与水质指标综合分析,鸭河口水库处于中营养状态.     

Kinematic analysis of the shot-put: A method of assessing the mechanical work of the hand action force

The aims of this study were to (1) propose a method for evaluating shot-putters mechanical power, (2) investigate the relationship between mechanical work of hand action force (W_HAF), peak power output (PPO) of different limbs and shot-put performance and (3) show which of these two parameters (W_HAF, PPO) were the most appropriate to characterize the explosive abilities of the shot-putter. Twelve junior right-handed shot-putters, practised glide technique shot-put throwers (personal best?=?13.57 ± 1.72 m), participated in this study. Arm and leg force-velocity tests were performed to measure PPO. Kinematic analysis was conducted during a shot-putting event in regular conditions to quantify the W_HAF at the release moment and shot-put performance. Significant correlations were found between absolute arm and leg PPO with upper and lower muscle volumes (r?=?.67; p?=?.03; r?=?.76; p?=?.01; r?=?.74, p?=?.01; r?=?.65, p?=?.04). Positive relationships were recorded between absolute arm and leg PPO and shot-put performance (r?=?.67, p?=?.02; r?=?.81, p?=?.004, respectively). Shot-put performance was also closely related to the W_HAF (r?=?.93, p?=?.0001) and release velocity parameter (r?=?.86, p?=?.001). The present results confirm that force-velocity test and W_HAF constitute useful tools for assessing mechanical power in throwing. The W_HAF could be considered as more suitable than force-velocity test.     

铁磁性材料磁性参数检测装置设计与实现北大核心

针对铁磁性材料无损检测实验平台建设需求,设计了基于磁滞回线法的铁磁性材料磁性参数检测实验装置。装置为嵌入式硬件平台,包括主控及信号发生、功放、感应信号调理等7个模块,并开发了磁性参数检测应用软件,实现了数据通信、界面显示、数据管理等多种功能,根据CR12MOV钢板磁性参数检测实验结果表明,装置可绘制磁滞回线并获得矫顽力和剩磁参数数值。该装置融合多学科特性,为无损检测专业实验室建设提供了一种有效的综合实验及实践平台。     

男子百米一级与二级运动员起跑和 前3步加速三维技术分析

目的:探讨男子百米一二级运动员起跑加速技术差异及影响短跑起跑加速效果的主要因素。方法:采用三维高速红外摄像解析法对男子百米一级运动员(6名)和二级运动员(7名)的起跑和前3步加速技术动作进行分析。结果:①起跑器上阶段一二级运动员摆动腿屈髋角速度峰值具有显著性差异(P<0.05),摆动腿屈髋角速度峰值与平均水平速度呈正相关(P<0.05),与支撑时间呈负相关(P<0.05);②第1步水平速度与支撑时间、支撑距离呈正相关(P<0.05),第2步水平速度与支撑时间、支撑距离呈正相关(P<0.05),与腾空时间呈负相关(P<0.05);③起跑和前3步加速一二级运动员平均步频与平均水平速度之间呈正相关(P<0.05)。结论:起跑和前3步加速不同阶段的技术特点是不同的,起跑器上阶段是为了获得较大起动速度,因此要求较大的摆动腿屈髋角速度峰值、更短的支撑时间,而第1步和第2步加速阶段提高水平速度则需要更长的支撑时间、支撑距离和更短的腾空时间,起跑和前3步加速较快的步频有利于水平速度的提高。