中外优秀标枪运动员投掷步技术的运动学比较

通过对我国优秀标枪运动员和世界优秀标枪运动员投掷技术的运动学比较研究.结果表明,现阶段我国标枪运动员投掷步技术存在的一些问题,是阻碍我国标枪运动水平进一步提高的主要原因.并针对这些问题,提出相应的训练方法和技术改进措施,使训练更具有针对性与目的性.     

几种碱改性ACF电极材料对电容性吸附处理RO浓水氨氮及其动力学研究

实验选用Na OH、KOH及氨水为电容性吸附电极材料活性碳纤维ACF的改性剂,通过比较原材料与几种改性材料去除盐分和氨氮效果,研究其电容性吸附氨氮动力学过程,实验结果表明:改性ACF相比未改性活性碳纤维电容性吸附污染物质发生变化,其中氨氮改性后ACF在盐分和氨氮去除上都表现出优越性,ACF-NH3除盐平均去除率达到9.69%,高于ACF-unmodified5.29%,氨氮平均去除率达到41.80%,高于改性前的27.33%;Na OH和KOH改性ACF在氨氮去除上均低于改性前,但其平均除盐率分别为6.53%、6.64%高于改性前;准一级、二级和Elovich经典动力学模拟其氨氮吸附动力学表明准一级和二级动力学具有更高的R2但其qe值误差较大,相比Elovich则能反应出其吸附趋势;另外,通过高斯多项式模拟结果和趋势均较经典动力学符合其吸附过程,R2均大于0.9557,一定程度上可以借鉴使用。     

4-一溴联苯醚的紫外光降解反应研究

以汞灯为光源研究了4-一溴联苯醚在有机溶剂中的光化学反应特性,探讨了初始浓度、紫外光源和溶剂介质对其光解速率的影响。结果表明,4-一溴联苯醚在有机溶剂中的紫外光降解均符合准一级动力学规律;300 W汞灯下,4-一溴联苯醚在不同有机溶剂中的光解速率存在明显差异,其在正己烷中的降解速率与甲醇接近,分别为1.22 min-1和1.20 min-1,而在丙酮中光解速率显著降低,仅为0.0082 min-1;光源强度越高,4-一溴联苯醚降解速率越快;因竞争吸光作用,溶液初始浓度也对4-一溴联苯醚的光解反应有影响,初始浓度增高其降解速率减慢。     

Musculoskeletal stiffness during hopping and running does not change following downhill backwards walking

Eccentric contractions that provide spring energy can also cause muscle damage. The aim of this study was to explore leg and vertical stiffness following muscle damage induced by an eccentric exercise protocol. Twenty active males completed 60 minutes of backward-walking on a treadmill at 0.67 m/s and a gradient of ? 8.5° to induce muscle damage. Tests were performed immediately before; immediately post; and 24, 48, and 168 hours post eccentric exercise. Tests included running at 3.35 m/s and hopping at 2.2 Hz using single- and double-legged actions. Leg and vertical stiffness were measured from kinetic and kinematic data, and electromyography (EMG) of five muscles of the preferred limb were recorded during hopping. Increases in pain scores (over 37%) occurred post-exercise and 24 and 48 hours later (p < 0.001). A 7% decrease in maximal voluntary contraction occurred immediately post-exercise (p = 0.019). Changes in knee kinematics during single-legged hopping were observed 168 hours post (p < 0.05). No significant changes were observed in EMG, creatine kinase activity, leg, or vertical stiffness. Results indicate that knee mechanics may be altered to maintain consistent levels of leg and vertical stiffness when eccentric exercise-induced muscle damage is present in the lower legs.     

Skating mechanics of change-of-direction manoeuvres in ice hockey players

Ice hockey requires rapid transitions between skating trajectories to effectively navigate about the ice surface. Player performance relates in large part to effective change-of-direction manoeuvres, but little is known about how those skills are performed mechanically and the effect of equipment design on them. The purpose of this study was to observe the kinetics involved in those manoeuvres as well as to compare whether kinetic differences may result between two skate models of varying ankle mobility. Eight subjects with competitive ice hockey playing experience performed rapid lateral (90°) left and right change-of-direction manoeuvres. Kinetic data were collected using force strain gauge transducers on the blade holders of the skates. Significantly greater forces were applied by the outside skate (50–70% body weight, %BW) in comparison to the inside skate (12–24%BW, p < 0.05). Skate model and turn direction had no main effect, though significant mixed interactions between leg side (inside/outside) with skate model or turn direction (p < 0.05) were observed, with a trend for left-turn dominance. This study demonstrates the asymmetric dynamic behaviour inherent in skating change-of-direction tasks.     

Effects of small-volume soccer and vibration training on body composition,aerobic fitness,and muscular PCr kinetics for inactive women aged 20–45

PurposeThe present study investigated the effects of 16 weeks of small-volume, small-sided soccer training soccer group (SG, n = 13) and oscillating whole-body vibration training vibration group (VG, n = 17) on body composition, aerobic fitness, and muscle PCr kinetics in healthy inactive premenopausal women in comparison with an inactive control group (CO, n = 14).MethodsTraining for SG and VG consisted of twice-weekly 15-min sessions with average heart rates (HRs) of ∼155 and 90 bpm respectively. Pre- and post-measurements of body composition (DXA), phosphocreatine (PCr) on- and off-kinetics, and HR measurements during standardised submaximal exercise were performed.ResultsAfter 16 weeks of training in SG, fat percentage was lowered (p = 0.03) by 1.7% ± 2.4% from 37.5% ± 6.9% to 35.8% ± 6.2% and the PCr decrease in the quadriceps during knee-extension ramp exercise was attenuated (4% ± 8%, p = 0.04), with no changes in VG or CO (time-group effect: p = 0.03 and p = 0.03). Submaximal exercise HR was also reduced in SG after 16 weeks of training (6% ± 5% of HR_max, p = 0.01).ConclusionShort duration soccer training for 16 weeks appears to be sufficient to induce favourable changes in body composition and indicators of aerobic fitness and muscle oxidative capacity in untrained premenopausal women.     

TiN薄膜常压化学气相沉积及动力学研究

在玻璃基片温度400℃和650℃之间，讨论了TiCl4-NH3-N2体系TiN常压化学气相沉积（APCVD）及动力学。在500－650℃温度范围内。TiN在高温玻璃表面沉积为反应物扩散控制，低于400℃为表面反应控制，其沉积速度明显受玻璃温度，反应物浓度和气体流速影响。     

梁富亮单杠团身后空翻一周半越杠再握动作的运动学分析

通过运动学分析揭示了我国优秀运动员完成的单杠团身后空翻一周半越杠再握动作的运动学规律与技术特点,对于进一步发展此类动作有积极的作用.     

脂肪酸合成酶缩合中心的羧负离子结合部位

本文对六个修饰巯基的试剂失活脂肪酸合成酶(FAS)的动力学进行了系统研究,发现它们与FAS的作用是否属于亲和标记,修饰巯基时的专一性,以及盐和NADPH有无保护,均只与该试剂分子中有无羧基负离子有关,提出在FAS的缩合中心存在一个对羧负离子有特异亲和力的结合部位.该部位可能是丙二酰基在缩合中心的结合部位,为缩合反应所必需,它使携带了丙二酰基的活臂向缩合中心运动,并结合于此进行缩合反应.     

火山岩型铀矿中基性岩与铀成矿作用研究

传统地球化学理论认为火山岩型铀矿的热液铀矿床中的铀都是通过氧化溶液搬运的,并由六价还原成四价而沉淀成矿;或者是是碱交代作用形成的。但大量的文献表明,铀的成矿不仅与火山岩和次火山岩有关,还与深源的中基性岩有关。