运用表面肌电信号对山西省射箭运动员技术特征分析初探

表面肌电图是从肌肉表面通过电极引导、记录下来的神经肌肉系统活动时的生物电信号。文章测定了山西省12名射箭运动员在日常训练时6块肌肉的肌电信号,并与国家队队员肌电信号进行对比分析和探索山西省射箭运动员技术特征。     

机械加工表面形貌的分形特性表征

为了表征机械加工表面形貌分形特征,介绍了用结构函数计算加工表面分形维数的方法.以车削加工和镗削加工作为算例,分别给出了粗糙度Ra为1.6μm和3.2μm的四种表面形貌图片和形貌曲线,应用结构函数法表征了表面形貌的分形维数.计算结果表明,同种加工方法的不同粗糙度下表面形貌具有较强相似性.     

Pinless Friction Stir Welding of AA2024-T3 Joint and Its Failure Modes

The joining of aluminum alloy sheets with thickness less than 2.0 mm is difficult via conventional frictionstir welding owing to the defects in the joint, such as root flaw, keyhole and lazy S. In the present research, a newlydesigned pinless tool with involute grooves on its shoulder surface was applied to weld 1.5 mm thick AA2024-T3. Theeffects of the rotating speed and welding speed on the microstructure and mechanical properties of the joints were analyzed.The experimental results showed that the root flaw and keyhole were successfully eliminated. The lazy S wasalso eliminated under the optimized welding parameters. The maximum tensile strength of the joints was 326 MPa,which is about 74.1% that of the base material. Moreover, all the tensile samples fractured from the retreating side.Two fracture modes were observed during the tensile tests, which are related with the lazy S.     

Pedagogy to empower Chinese Learners to adapt to western learning circumstances: a longitudinal case-study

Deficit theorisations of Chinese Learners studying in western countries are criticised for dichotomising learning attributes into Surface- or Deep-learning approaches. Subsequent context-dependent, small culture studies of students transiting between cultures theorise learning as a dynamic journey of adapting to a range/continuum of learning attributes. Here we employ the transformative learning theory to examine whether pedagogical interventions could facilitate adaptation to deeper learning strategies by couching discipline-specific detail/facts within the discipline’s theoretical structure. Our longitudinal case-study of Chinese Learners in an Australian tertiary institution revealed that (1) Achievement-motivated CLs were more likely to harness the benefits of this discipline-specific pedagogical intervention and move towards independent, student-centred learning than Surface-motivated CLs; (2) Achievement-motivated CLs were less likely to normalise teacher-centredness than Surface-motivated CLs despite being exposed to examination tips early in their enrolment; and (3) fluency in the host language is instrumental to adapting successfully to deeper learning.     

沥青路面除冰雪技术研究(英文)

为降低路面和冰雪之间的黏结力,用有机硅憎水材料作为道路表面涂层.有机硅憎水涂层技术的除冰效果用接触角实验和剪切实验来表征,其耐久性用加速加载磨耗实验来评价,而其抗滑性能则用摆式摩擦法和铺砂法来评价.接触角实验结果表明,有机硅憎水涂层材料与水的接触角为100.2°,具有很好的憎水性能.其次,通过剪切实验可以得出:在涂有有机硅憎水材料的情况下,冰层与试件表面的最大剪切应力仅为0.06 MPa,低于没有进行表面涂层处理的最大剪切力3.5 MPa;剪切之后,冰层能够很完整地从试件表面脱落.加速加载磨耗实验表明,在经过一定时间的磨耗之后,残留在沥青路面构造深度里的有机硅涂层材料仍然具有除冰雪的效果.表面涂层后的道路表面的BPN值和构造深度值均有所降低,但是其仍然远远大于规范的要求,确保了安全性.研究表明,沥青道路表面涂层技术能有效地降低沥青路面与冰层的黏结,从而解决冬季道路结冰影响行车安全的问题.     

基于反向萤火虫算法的多阈值缺陷图像分割(英文)

为了分割QFN表面的缺陷,提出一种基于反向萤火虫算法的大津多阈值分割法.首先,将大津阈值分割扩展为大津多阈值分割.其次,提出了一种基于反向学习的萤火虫算法.在该算法中,生成的反向萤火虫用于增加萤火虫的多样性和全局搜索能力.然后,将基于反向学习的萤火虫算法应用于多阈值分割.最后,使用所提出的方法对QFN缺陷图像进行阈值分割实验,并将结果与穷举法、基于粒子群算法的大津多阈值分割法、基于萤火虫算法的大津多阈值分割法进行比较.实验结果表明,所提方法能更有效地分割QFN表面缺陷,且分割速度快.     

基于边界摩擦的碟簧隔振器力学性能(英文)

为研究边界摩擦对碟簧隔振器力学性能的影响,基于能量守恒定律推导了在考虑边界摩擦时碟簧隔振器的载荷位移迟滞曲线公式.通过有限元分析与静载试验验证了该公式的正确性.在此基础上研究了边界摩擦对碟簧隔振器承载能力的影响,并通过动载试验研究了边界摩擦对碟簧隔振器的动态性能的影响.试验结果表明:边界摩擦可提供较大的阻尼,使得碟簧隔振器具有良好的阻尼特性,其阻尼比可达0.23;隔振器的耗能、动刚度和阻尼特性对加载幅值更为敏感,而对加载频率敏感度较小.该研究成果对碟簧隔振器设计具有重要的指导意义.     

Constructive,collaborative, contextual,and self‐directed learning in surface anatomy education

Anatomy education often consists of a combination of lectures and laboratory sessions, the latter frequently including surface anatomy. Studying surface anatomy enables students to elaborate on their knowledge of the cadaver's static anatomy by enabling the visualization of structures, especially those of the musculoskeletal system, move and function in a living human being. A recent development in teaching methods for surface anatomy is body painting, which several studies suggest increases both student motivation and knowledge acquisition. This article focuses on a teaching approach and is a translational contribution to existing literature. In line with best evidence medical education, the aim of this article is twofold: to briefly inform teachers about constructivist learning theory and elaborate on the principles of constructive, collaborative, contextual, and self‐directed learning; and to provide teachers with an example of how to implement these learning principles to change the approach to teaching surface anatomy. Student evaluations of this new approach demonstrate that the application of these learning principles leads to higher student satisfaction. However, research suggests that even better results could be achieved by further adjustments in the application of contextual and self‐directed learning principles. Successful implementation and guidance of peer physical examination is crucial for the described approach, but research shows that other options, like using life models, seem to work equally well. Future research on surface anatomy should focus on increasing the students' ability to apply anatomical knowledge and defining the setting in which certain teaching methods and approaches have a positive effect. Anat Sci Educ 6: 114–124. © 2012 American Association of Anatomists.     

Expanding Talent Search Procedures by Including Measures of Spatial Ability: CTY's Spatial Test Battery

The importance of spatial ability for success in a variety of domains, particularly in science, technology, engineering, and mathematics (STEM), is widely acknowledged. Yet, students with high spatial ability are rarely identified, as Talent Searches for academically talented students focus on identifying high mathematical and verbal abilities. Consequently, students with high spatial abilities who do not also have high math or verbal abilities may not qualify. In an effort to identify students with spatial talent, the Center for Talented Youth developed a Spatial Test Battery to supplement its mathematical and verbal Talent Searches. This article traces the development of the battery; describes its components, important psychometric properties, and continuing development; and encourages its use by researchers and educators interested in developing spatial talent.     

大学本科集成电路实验教学改革设想

集成电路实验是电子科学与技术专业的重要专业实验课,以往教学中存在着教学方法陈旧、实验课程联系松散和实验软件落后等问题。难以适应新时期人才培养的需要。教学改革势在必行。从高等院校集成电路实验课程的教学目标入手,应用“点”与“面”相结合的教学手段和形式多样的教学方法对课程进行改革创新,突出学生的主体作用,因材施教。可以有效提高教学效果。提升学生的创新能力。