酸枝锯末对Cr(VI)的吸附研究

实验研究了酸枝锯末对模拟含铬废水中的Cr（VI）的吸附性能,静态吸附结果表明,酸枝锯末对Cr（VI）具有较好的吸附效果．锯末对Cr（VI）的吸附率随着锯末用量的增加而增大;随着溶液初始pH的增大,吸附效果降低;随着吸附温度的上升,吸附效果升高．酸枝锯末对Cr（VI）的吸附符合拟二级吸附动力学模型（R2〉0．99）,吸附平衡前,颗粒内扩散为吸附速率的主要控制步骤;吸附过程可用Langmuir吸附等温线（砰〉0．99）来描述．吸附热力学研究表明,酸枝锯末对Cr（VI）的吸附为自发的吸热反应过程．     

跳深跳远练习和跳远踏跳的动力学比较研究

采用文献研究及在实验室条件下的动力学测试,对跳深跳远练习与跳远踏跳在形式、内容上的相似程度和差异点进行对比分析。结果显示,跳深跳远练习可以作为发展跳远起跳力量的专门训练手段。     

110m栏运动员摆动动作的运动学特征

运用高速摄影及影片解析法获取了我国优秀男子 110m栏运动员第六栏跨栏步技术摆动动作的相关运动学指标。研究结果表明 :我国优秀男子 110m栏运动员跨栏步摆动动作的时相划分为 :大腿分前摆与下压两个亚时相 ,小腿分折叠、打开与保持三个亚时相。摆动腿下压的时机始于身体重心位于栏上瞬时 ,大约经过 0 .0 31s的时间 ,起跨腿加速向前提拉。整个跨栏步摆动腿前摆时间是下压时间的 1.2 5倍 ,前摆的平均角速度慢于下压的平均角速度 ;小腿打开时间是折叠时间的 4 .5 5倍 ,小腿折叠的平均角速度约为打开的 1.74倍     

江西省相山铀矿田成矿条件探讨

本文主要阐述了相山铀矿田的成矿条件。相山铀矿田是我国最大的火山岩型铀矿田,研究其成矿条件对今后找矿工作有十分重要的意义。本文主要从构造背景、物质条件、断裂构造和保矿条件这几方面进行探讨。     

不稳定结构鞋具的运动生物力学研究进展

不稳定结构鞋具的使用改变了人体运动系统的动力学、运动学和肌肉群的运动强度,使运动系统更加充分的调动。大量的生物力学实验已证实,不稳定结构的鞋具可以对人体下肢运动系统进行改变。本文较完善的总结了近期国内外研究文献对于不稳定鞋具的功能论证,探讨了各种不稳定结构设计的鞋具在加强肌肉力量训练、改善运动稳定和损失预防的不同效果。对于长期穿着稳定结构鞋具的人群,为其运动习惯的变化提供了一种有效途径。     

Optimization of elastolysis conditions and elastolytic kinetic analysis with elastase from Bacillus licheniformis ZJUEL31410

INTRODUCTION Elastases are heterogeneous with differing sub-strate specificities and catalytic mechanisms. In fact, enzymes with elastolytic activity can be found in most of the major proteolytic families, including serine, thiol, aspartic, and metallo-enzymes. Despite the differences in catalytic mechanisms, all of these elastases share a common specificity for cleaving peptide bonds associated with hydrophobic or aro-matic amino acids (Hall and Czerkawaki, 1961). Bacterial elastases b…     

短跑途中跑支撑阶段运动学与动力学特征新研究

采用测力与同步摄像方法,对原始解析坐标数据利用测量到的力的数据计算身体重心的加速度,并采用“积分平滑”的方法研究短跑途中跑支撑阶段身体重心的运动学特征,水平与垂直速度的获得由积分获得。从力的原始数据中分析跑的压心与反作用的方向变化。研究结果显示：短跑途中跑身体重心最低点在整个支撑阶段标准化时刻的30％左右,前支撑阶段运动员有加速用力现象,此加速用力虽影响水平速度,但对提高垂直速度有积极意义,垂直速度在标准化支撑时间的80％处开始下降;途中跑支撑阶段压心从着地时的跖趾骨处急速向踝关节移动后又逐渐向前移动到第二跖关节附近,着地时反作用力的方向有两次向后“突变”。采用的积分平滑运动学数据的技术措施能有效提高计算的精确度。     

水滑石改性氰酸酯纳米复合材料的固化动力学研究

采用动态差示扫描量热法（DSC）对不同含量氰酸酯/水滑石复合体系进行了固化反应动力学研究,通过Kissinger法、Ozawa法和Crane法计算了复合体系的反应活化能及反应级数等固化反应参数.结果表明,水滑石纳米粒子的加入使氰酸酯固化反应放热峰的峰值温度和反应终止温度明显降低,同时降低了固化反应的表观活化能,但反应级数基本不变.这说明纳米水滑石的加入对固化反应有一定的促进作用,但并不改变氰酸酯的固化反应机理.     

The effects of mid-flight whole-body and trunk rotation on landing mechanics: implications for anterior cruciate ligament injuries

ABSTRACT

The purpose was to quantify the effects of mid-flight whole-body and trunk rotation on knee mechanics in a double-leg landing. Eighteen male and 20 female participants completed a jump-landing-jump task in five conditions: no rotation, testing leg ipsilateral or contralateral (WBRC) to the whole-body rotation direction, and testing leg ipsilateral (TRI) or contralateral to the trunk rotation direction. The WBRC and TRI conditions demonstrated decreased knee flexion and increased knee abduction angles at initial contact (2.6 > Cohen’s dz > 0.3) and increased peak vertical ground reaction forces and knee adduction moments during the 100 ms after landing (1.7 > Cohen’s dz > 0.3). The TRI condition also showed the greatest knee internal rotation angles at initial contact and peak knee abduction and internal rotation angles and peak knee extension moments during the 100 ms after landing (2.0 > Cohen’s dz > 0.5). Whole-body rotation increased contralateral knee loading because of its primary role in decelerating medial-lateral velocities. Trunk rotation resulted in the greatest knee loading for the ipsilateral knee due to weight shifting and mechanical coupling between the trunk and lower extremities. These findings may help understand altered trunk motion in anterior cruciate ligament injuries.     

Muscle force characteristics of male and female collegiate cross-country runners during overground running

ABSTRACT

Males and females demonstrate unique running mechanics that may contribute to sex-related differences in common running related injuries. Understanding differences in muscle forces during running may inform intervention approaches, such as gait retraining addressing muscle force distribution. The purpose of this study was to compare muscle force characteristics and inter-trial variability between males and females during running. Twenty female and 14 male collegiate cross-country runners were examined. Three-dimensional kinetic and kinematic data were collected during overground running and used to estimate muscle forces via musculoskeletal modelling. Principle components analysis was used to capture the primary sources of variance from the muscle force waveforms. The magnitude of the forces for the hamstrings, gastrocnemius, and soleus muscles were higher across the majority of stance in male runners regardless of footstrike pattern. Males also demonstrated greater inter-trial variability in the timing of the peak gluteus maximus force and the magnitude of local peaks in the gastrocnemius force waveform. Male and female collegiate cross-country runners appear to employ unique lower extremity muscle force characteristics during overground running.