Mid-flight lateral trunk bending increased ipsilateral leg loading during landing: a center of mass analysis

Increased lateral trunk bending to the injured side has been observed when ACL injuries occur. The purpose was to quantify the effect of mid-flight lateral trunk bending on center of mass (COM) positions and subsequent landing mechanics during a jump-landing task. Forty-one recreational athletes performed a jump-landing task with or without mid-flight lateral trunk bending. When the left and right trunk bending conditions were compared with the no trunk bending condition, participants moved the COM of the upper body to the bending direction, while the COM of the pelvis, ipsilateral leg, and contralateral leg moved away from the bending direction relative to the whole body COM. Participants demonstrated increased peak vertical ground reaction forces (VGRF) and knee valgus and internal rotation angles at peak VGRF for the ipsilateral leg, but decreased peak VGRF and knee internal rotation angles at peak VGRF and increased knee varus angles at peak VGRF for the contralateral leg. Mid-flight lateral trunk resulted in an asymmetric landing pattern associated with increased ACL loading for the ipsilateral leg. The findings may help to understand altered trunk motion during ACL injury events and the discrepancy in ACL injuries related to limb dominance in badminton and volleyball.     

Conditioning exercises in ski jumping: biomechanical relationship of squat jumps,imitation jumps,and hill jumps

As hill jumps are very time-consuming, ski jumping athletes often perform various imitation jumps during training. The performed jumps should be similar to hill jumps, but a direct comparison of the kinetic and kinematic parameters has not been performed yet. Therefore, this study aimed to correlate 11 common parameters during hill jumps (Oberstdorf Germany), squat jumps (wearing indoor shoes), and various imitation jumps (rolling 4°, rolling flat, static; jumping equipment or indoor shoes) on a custom-built instrumented vehicle with a catch by the coach. During the performed jumps, force and video data of the take-off of 10 athletes were measured. The imitation and squat jumps were then ranked. The main difference between the hill jumps and the imitation and squat jumps is the higher maximal force loading rate during the hill jumps. Imitation jumps performed on a rolling platform, on flat ground were the most similar to hill jumps in terms of the force–time, and leg joint kinematic properties. Thus, non-hill jumps with a technical focus should be performed from a rolling platform with a flat inrun with normal indoor shoes or jumping equipment, and high normal force loading rates should be the main focus of imitation training.     

水溶性苯胺蓝的热氧降解过程与动力学

用差热分析方法（ＤＴＡ）、热重分析法（ＴＧ）和微分热重分析法（ＤＴＧ）研究水溶性苯胺蓝在空气中流中的热氧降解过程和动力学,发现水溶性苯胺蓝热氧降解过程由３个紧连步骤组成．用ＣｏａｔｓＲｅｄｆｅｒｎ方程进行动力学处理,确定水溶性苯胺蓝热氧降解的表观反应级数分别为１７,２０,０９和活化能为２５４６,３３１５,５９７７ｋＪ／ｍｏｌ．     

化学创新与新型农业

就化学创新及其在农业上的应用方面进行了综述,主要叙述了化学创新与现代农业的关系及发展前景.本文引用了文献19篇.     

影响高校高水平男子三级跳远各阶段速度因素的运动参数分析

通过高速摄影和录像解析等方法对湖北省2008高校高水平男子三级跳远运动员三跳各阶段水平速度变化情况进行相关比较与研究,结果显示,高校高水平男子三级跳远运动员各时相水平速度在助跑、踏板、起跳、单足跳、跨步跳、跳跃等由于诸多因素造成水平速度降低,特别是跨步跳造成的损失成为影响总成绩的关键。     

3-(2-氨基-2-氧乙基)-1-丁基咪唑二氰胺盐对环氧树脂(E-51)的固化工艺

以新型离子液体3-（2-氨基-2-氧乙基）-1-丁基咪唑二氰胺盐（AOBD）作为双酚A型环氧树脂（E-51）的固化剂,深入研究其固化工艺和固化物的性能。结果表明：AOBD可用作E-51的高温固化剂,二者最佳配比为AOBD/E51=10：100,最佳固化温度范围为122~156℃,后固化温度为178℃。固化后E-51浇注体的拉伸强度为30.7 MPa,拉伸模量为3 233.1 MPa,断裂伸长率为1.1%,热分解温度为414.0℃。动态力学分析表明,浇注体的最大损耗因子为0.56,玻璃化转变温度为174.8℃,贮存模量为134.8 MPa,交联密度为3 198.9 mol·m^-3。红外光谱测试表明AOBD的固化反应包括两个阶段,首先-CONH₂在低温下与环氧基团发生开环反应,然后阴离子与环氧基在高温下进一步反应提高交联密度。     

《化学反应工程》教学实践总结

《化学反应工程》是化学工程专业学生的必修课之一,对于培养学生的工程概念、工程分析能力具有十分重要的作用。本文阐述了在课程的实际教学过程中,改进教学方式,精选教材内容,综合能力考核等方面的实践探索与体会。     

基于工作过程的“化工机械设备技术”课程改革与实践

化工机械设备技术是一门理论与实践结合紧密,综合性和实践性很强的专业课程,按照基于工作过程的项目化教学方式组织实施教学,有利于实现教学目标。文章从课程体系、教学内容、教学手段、考核方法等方面对该课程的改革进行了探索,并提出了解决办法。     

国内外大学化学课程设置分析与比较——兼谈高校化学教学改革与创新

目前,我国高等教育正处在一个高速发展的时期,随着高校教学改革的不断深入,高等教育由精英化教育逐步向普及化教育转变,高校也越来越重视应用型、复合型人才的培养。新的转变与发展对我国高校专业课程设置、培养方案等都提出了更高的要求。大学化学课程是高校理工科专业的必修基础课,文章通过对国外大学化学专业课程设置和培养理念的分析,结合国内高校化学课程教学发展现状,提出国内高校化学教学改革与创新的措施。     

改进高职高专《化学工艺学》教学方法的思考

通过对高职高专《化学工艺学》的教学现状进行分析,提出了改进高职高专《化学工艺学》教学方法的几条建议。