圆形载流线圈沿一直径折成直角可看作磁偶极子

从磁偶极子的特点出发,用毕奥—萨伐尔定律、安培力公式和力矩的定义,推导出用磁矩表示的圆形载流线圈沿一直径折成直角的远场及其在均匀磁场中所受的磁力和磁力矩,指出此非平面载流线圈可看作磁偶极子.     

马克思主义生产力理论的科学性及其在当代中国的创造性发展

以唯物史观和唯物主义辩证法两大锐利思想武器作为马克思主义生产力理论方法论基础的确立,是马克思主义生产力理论成为科学的理论以及与西方经济学理论相区别的最本质的特征;马克思主义生产力理论方法论基础、所揭示的基本原理(生产力发展规律)与其科学的分析框架之间的内在逻辑一致性,是马克思主义生产力理论科学性的本质体现;邓小平关于“科学技术是第一生产力”的思想,是马克思主义生产力理论在当代中国的创造性发展。     

跨越经济与伦理的鸿沟：公有资本人格化问题的再探究

在全面建设小康社会和构建社会主义和谐社会的进程中,要坚持和完善公有制为主体的基本经济制度,必须使公有资本不断地保值增值,需要充分发挥公有资本人格化的道德力量。如何实现公有资本人格化,这是国有企业摆脱目前困境的根本途径之一,也是我国当前构建社会主义和谐社会的伦理道德基础。     

理性和意志碰撞的体育动力论

在进一步研究体育的本质问题时发现：理性制约意志驱动体育动力来源发生着碰撞,理性不是唯一的,意志也不是唯一的,彼此之间超越一方达到极至,将产生一种失衡状态,客观地存在着控制与反控制的动力平衡点,这个过程被人类社会秩序完整地掌握和调控。表现在：体育意志试图超越理性的界碑,但总是被限制;理性试图超越意志的体育灵魂,也经受到有力的打击;当理性制约意志的体育动力时,也发生着因果关系的转换。     

Kinematic and kinetic analysis of overhand,sidearm and underhand lacrosse shot techniques

Lacrosse requires the coordinated performance of many complex skills. One of these skills is shooting on the opponents’ net using one of three techniques: overhand, sidearm or underhand. The purpose of this study was to (i) determine which technique generated the highest ball velocity and greatest shot accuracy and (ii) identify kinematic and kinetic variables that contribute to a high velocity and high accuracy shot. Twelve elite male lacrosse players participated in this study. Kinematic data were sampled at 250 Hz, while two-dimensional force plates collected ground reaction force data (1000 Hz). Statistical analysis showed significantly greater ball velocity for the sidearm technique than overhand (P < 0.001) and underhand (P < 0.001) techniques. No statistical difference was found for shot accuracy (P > 0.05). Kinematic and kinetic variables were not significantly correlated to shot accuracy or velocity across all shot types; however, when analysed independently, the lead foot horizontal impulse showed a negative correlation with underhand ball velocity (P = 0.042). This study identifies the technique with the highest ball velocity, defines kinematic and kinetic predictors related to ball velocity and provides information to coaches and athletes concerned with improving lacrosse shot performance.     

Assessment of leg muscles mechanical capacities: Which jump,loading, and variable type provide the most reliable outcomes?

This study aimed to explore the strength of the force–velocity (F–V) relationship of lower limb muscles and the reliability of its parameters (maximum force [F₀], slope [a], maximum velocity [V₀], and maximum power [P₀]). Twenty-three men were tested in two different jump types (squat and countermovement jump: SJ and CMJ), performed under two different loading conditions (free weight and Smith machine: Free and Smith) with 0, 17, 30, 45, 60, and 75?kg loads. The maximum and averaged values of F and V were obtained for the F–V relationship modelling. All F–V relationships were strong and linear independently whether observed from the averaged across the participants (r?≥?0.98) or individual data (r?=?0.94–0.98), while their parameters were generally highly reliable (F₀ [CV: 4.85%, ICC: 0.87], V₀ [CV: 6.10%, ICC: 0.82], a [CV: 10.5%, ICC: 0.81], and P₀ [CV: 3.5%, ICC: 0.93]). Both the strength of the F–V relationships and the reliability of their parameters were significantly higher for (1) the CMJ over the SJ, (2) the Free over the Smith loading type, and (3) the maximum over the averaged F and V variables. In conclusion, although the F–V relationships obtained from all the jumps tested were linear and generally highly reliable, the less appropriate choice for testing the F–V relationship could be through the averaged F and V data obtained from the SJ performed either in a Free weight or in a Smith machine. Insubstantial differences exist among the other combinations tested.     

振动力量训练对跳远运动员膝关节肌力变化影响的实验

为了拓宽专项力量训练途径,丰富和创新力量训练方法,通过振动力量训练组(II组)和传统力量训练组(I)对比实验研究来探索振动力量训练对跳远运动员下肢肌肉力量训练效果的影响规律,为进一步振动力量训练发展和应用提供实验依据。实验结果表明:振动力量训练法能在同等的负荷条件下,能更有效地发展运动员膝关节屈肌群的最大力量、快速力量、爆发力,其中伸肌表现不明显;振动力量训练也提高了运动员的膝关节肌群力量耐力水平,同时使膝关节屈伸肌群得到协调发展。     

体校学生田径训练中单足跳发展下肢爆发力的研究

文章对体校学生爆发力训练进行了理论研究,提出了爆发训练的专项性原则及应注意的问题,并确定了体校学生单腿训练的依据及方法,希望借此对体校的教学与训练提供一定参考。     

中国女子排球运动员后备力量相关指标剖析

调研以提高中国女子排球运动竞技水平为目的,以选拔、培养国家女排后备力量为组织核心的数届全国青年女排集训比赛的运动员为主要研究对象,采用文献资料、数理统计等方法,对其身体形态和专项身体素质数据进行分析。研究认为：近三年来全国青年女子排球运动员的年龄征象、身高水平相对稳定;主攻、副攻、二传、接应的体重、指高差异不显著、专位特色不鲜明;助跑摸高、6m×16次移动水平停滞不前;下肢垂直与水平爆发力等专项素质亟待提高;相关指标数据与国家女排运动员、甲A女排运动员有较大差距;身材高大的运动员仍较缺乏。     

简论推动现代排球运动发展的主要动力

本文对排球运动发展的历史过程进行分析、探讨,并从哲学角度运用自然辩证法进行论证,发现以寻求攻防平衡为目的的规则改变不断地改进和完善排球运动,使排球运动更加激烈、精彩;另外不同时期人们对排球各种功能的需求也有效地推动了排球运动的发展。它们是推动排球运动发展的主要因素。更好地把握和利用排球运动发展的动因能更好地促进排球运动的发展。