关于极矢量与轴矢量的探讨     

赵云辉 《邵阳学院学报(社会科学版)》2003,2(5):37-39

论述了极矢量与轴矢量一个重要方面的差异，介绍极矢量与轴矢量的判别方法，证明极矢量与轴矢量的一些矢量乘法规则．  相似文献   

静压轴承在内燃机车上的应用     

许克维  董谟禹 《河北软件职业技术学院学报》1999,(2)

介绍了静压轴承在内燃机车技术改造中的应用情况。受原有机构和空间的限制,静压轴承采用了一种新颖的结构──剖分式结构。通过此项技术改造,取得了良好的社会效益和经济效益。  相似文献   

浅谈单腿前翻身的基本技术分析与训练     

贾利 《福建体育科技》1999,(1)

通过对９６’麦克杯全国武术锦标赛中的难度动作单腿前翻身的技术动作分析,提出了具体的辅助性训练及建议,为武术教学提供参考依据。  相似文献   

利用CAXA电子图板分析正等轴测图     

杨三序  贾廷见  吕广申 《商丘职业技术学院学报》2010,9(5):25-27

用CAXA电子图板软件,由物体的正等轴测图的形成原理入手,绘制出视图并直接测量出精度为1×10-7mm的轴向伸缩系数的大小以及轴测轴对于投影面的倾斜角.此法简单易懂,对于学生来说,比复杂的数学推导过程更容易接受.  相似文献   

Effects of leg dominance on performance of ballet turns (pirouettes) by experienced and novice dancers     

Chia-Wei Lin  Fong-Chin Su  Hong-Wen Wu 《Journal of sports sciences》2013,31(16):1781-1788

Turns (pirouettes) are an important movement in ballet and may be affected by “lateral bias”. This study investigated physiological differences exhibited by experienced and novice dancers, respectively, when performing pirouette with dominant and non-dominant leg supports, respectively. Thirteen novice and 13 experienced dancers performed turns on dominant or non-dominant legs. The maximum ankle plantarflexion, knee extension and hip extension were measured during the single-leg support phase. The inclination angle of rotation axis is the angle between instantaneous rotation axis and global vertical axis in the early single-leg support phase. Both groups exhibited a greater hip extension, knee extension, and ankle plantarflexion when performing a turn on the non-dominant leg. For experienced dancers, the inclination angle of rotation axis during the pre-swing phase was generally smaller for dominant leg support than non-dominant leg. However, no significant difference was found in inclination angle of rotation axis of novice dancers. For experienced dancers, an improved performance is obtained when using the dominant leg for support. By contrast, for novice dancers, the performance is independent of choice of support leg. The significant lateral bias in experienced dancers indicates the possible influence of training. That is, repetitive rehearsal on the preferred leg strengthens the impact of side dominance in experienced dancers.  相似文献   

Skiing‐Skating     

Dustin Bruening  James G. Richards 《Sports biomechanics / International Society of Biomechanics in Sports》2013,12(2):215-225

An articulated boot design is commonly used in skiing and skating sports because it allows sagittal plane ankle mobility while still providing critical frontal plane stability. Although articulated boots have been in use for several decades, current manufacturers of these boots differ in their articulation placement. In this study we determined an optimal position of the ankle articulation axis. We also calculated the amount of anterior skin movement that a boot tongue must account for during a full range of ankle motion. Three‐dimensional kinematic data were collected and analyzed from 40 participants moving their right foot through a full range of sagittal plane motion. The calculated horizontal position of the articulation axis was found to be highly predictable from foot length (r = 0.87, standard error of estimate = 3.44 mm), while its vertical component displayed less predictability (r = 0.49, standard error of estimate = 7.46 mm). The expansion required by the boot tongue had a moderate association with foot length and low variability (r = 0.58, standard error of estimate = 0.07 mm). An accurate axis placement will minimize relative motion between the boot cuff and the ankle, reducing friction and motion resistance. An expandable tongue will accommodate full plantar flexion and reduce pressure on the anterior ankle during dorsiflexion, eliminating common pressure‐related injuries.  相似文献   

球面和圆柱面相等对应关系的研究     

杨道富  彭明 《商丘师范学院学报》2005,21(5):61-63

建立轴射圆柱面投影方法，研究轴射圆柱面投影下球面向圆柱面投影的理论，解决正投影无法解决的复杂的旋转体投影问题．用轴射圆柱面投影法的投影理论，建立球面和圆柱面的一一对应关系，找出二者之间的某些几何规律，该投影下任意形状的球面投影到圆柱面上是相等的，建立球面的轴射圆柱面投影定理，解决球面不规则计算问题．  相似文献   

人字齿轮传动轴系轴承选择     

张翠生 《河北能源职业技术学院学报》2003,3(1):71-72

通过对人字齿轮传动轴系分析研究发现，由于人字齿轮制做加工的误差，而导致轴系产生轴向移动，在设计、使用都不能忽视这个轴向移动。  相似文献   

标枪纵轴用力技术教学探讨     

郑贵忠 《天津体育学院学报》1996,11(3):46-48

采用文献研究，数理统计，比较研究等方法，对天津体院本科７个班约１４０人次标枪技术教学的纵轴用力技术问题及教学方法进行了探讨。实践证明，采用适当的教学方法，掌握正确的纵轴用力技术，是提高运动成绩的有效途径。  相似文献   

历史文献学归属小议     

钱高丽 《哈尔滨学院学报》2013,34(2):77-80

由于历史文献学的学科属性和研究对象在当前学术界仍然存在很大的争议。在此,文章在总结前辈们对于文献学,尤其是历史文献学的学科属性和研究对象等问题观点的基础上,通过应用文理交叉的交叉学科的研究方法,将历史文献学从大文献学中分出来并区别于其他专科文献学,进而阐述关于历史文献学的学科属性及其研究对象的一些看法。  相似文献