基于ANSYS的Au-Al引线键合热可靠性研究

采用ANSYS有限元分析软件建立Au-Al引线键合模型考察键合区在热循环加载下的应力应变情况;并采用Coffin-Manson方程计算了在热循环加载下焊点的疲劳寿命。结果表明：随着热加载循环次数的增加,模型的应力应变将增大;施加约束后,模型的应力将减小,引线键合的寿命延长。此方法可以比较各种不同情形下Au-Al引线键合热可靠性。     

地下金属管线探测传感器的改良和灵敏度的优化

以地下金属管线探测仪为背景,基于感应式磁传感器设计原理,通过对传感器线圈灵敏度进行深入分析,采用非晶态合金磁芯对现有的传感器线圈进行改进并实际设计了一款磁传感器线圈,理论计算了基于非晶态合金磁芯线圈的灵敏度,通过实验验证了新设计的磁传感器线圈达到灵敏度最优。     

普通高校声乐教学中歌唱技巧的有效探索

结合相关声乐理论知识和实际教学经验,探讨普通高校声乐教学中大多数同学困惑的,比如正确的腹式呼吸要领、外形漂亮的内外制约与协调作用以及突破高音技巧等三个方面的问题,探讨解决这些问题行之有效的方法,使学生能够正确、快速、有效地解决这些问题,从而不断提高自身的演唱水平。     

Perform kicking with or without jumping: joint coordination and kinetic differences between Taekwondo back kicks and jumping back kicks

We investigated joint coordination differences between Taekwondo back kicks and jumping back kicks, and how jumping (in performing the latter) would alter engaging ground reaction forces (GRF) in executing kicking. Ten skilful athletes volunteered to perform both kinds of kicking within the shortest time for three successful trials. Three high-speed cameras and two force platforms were used for data collection, and the trial with the shortest execution time was selected for analysis. Movements were divided into the rotation and attack phases. With comparable execution time and maximum joint linear/angular speeds, back kicks and jumping back kicks differ mainly in larger GRF in the latter, and in greater target acceleration in the former probably because the support leg prevented athletes’ rebounding after impact. In addition, more prominent antiphase and in-phase coordination between the shoulder segment and knee joint, and elongated rotation phase were found in jumping back kicks. Larger GRF values in jumping back kicks were generated for jump take-off rather than for a more powerful attack. In back kicks although the support leg remained ground contact, greatly decreased GRF in the attack phase suggested that the support leg mainly served as a rotation axis.     

Validation of two accelerometers to determine mechanical loading of physical activities in children

The purpose of this study was to assess the validity of accelerometers using force plates (i.e., ground reaction force (GRF)) during the performance of different tasks of daily physical activity in children. Thirteen children (10.1 (range 5.4–15.7) years, 3 girls) wore two accelerometers (ActiGraph GT3X+ (ACT), GENEA (GEN)) at the hip that provide raw acceleration signals at 100 Hz. Participants completed different tasks (walking, jogging, running, landings from boxes of different height, rope skipping, dancing) on a force plate. GRF was collected for one step per trial (10 trials) for ambulatory movements and for all landings (10 trials), rope skips and dance procedures. Accelerometer outputs as peak loading (g) per activity were averaged. ANOVA, correlation analyses and Bland–Altman plots were computed to determine validity of accelerometers using GRF. There was a main effect of task with increasing acceleration values in tasks with increasing locomotion speed and landing height (P < 0.001). Data from ACT and GEN correlated with GRF (r = 0.90 and 0.89, respectively) and between each other (r = 0.98), but both accelerometers consistently overestimated GRF. The new generation of accelerometer models that allow raw signal detection are reasonably accurate to measure impact loading of bone in children, although they systematically overestimate GRF.     

南通市普通高中体育隐性课程资源开发现状调查

运用文献资料、问卷调查和数理统计等研究方法对南通市普通高中体育隐性课程开发现状从物质和精神两个方面进行调研分析。结果显示,南通市普通高中学生对场地器材使用和体育课的安排满意度较低;课外活动管理松散;体育教师课堂管理中奖惩运用不合理、学生主体地位体现不足;学校体育信息资源匮乏等。根据调查结果提出了推进隐性课程资源开发的对策。     

一阶线性偏微分方程求解的教学方法新探

通过常微分方程与偏微分方程之间的关系我们寻找到一种特殊的规范变换,通过此变换将复杂的偏微分方程的求解转化为可积分的偏微分方程(含参数的常微分方程)的求解.     

二本院校本科毕业生社会归属感预期的实证分析

二本院校本科毕业生就业后是否被社会接受和认可是衡量二本院校高等教育成功与否的关键。对二本综合型院校K大学的本科毕业生进行随机采样,调查学生对社会归属感的预期情况,用多元回归分析方法对影响二本院校本科毕业生的归属感预期的主要因素进行了实证分析。研究发现二本院校毕业生所在学校的社会认可度、所学专业和就业意向的契合度、所学专业的社会认可度等因素对其社会归属感预期感存在显著影响。     

浅析《水浒传》与《侠盗罗宾汉》中的“劫法场”

《水浒传》与《侠盗罗宾汉》中都安排了"劫法场"这一情境。受刑人物的气质差异反映出中西方对于死亡的理解不同。从救人好汉的描写看,虽然两位作者都以限知视角突出了个人,但《水浒传》在群像描写上略胜一筹。两位作家对小人物的简单着墨,使作品中的人物类型丰富有过渡性。而在奸险小人的不同处置上,显示出中国封建社会仍是以暴制暴,而英国较为注重法治程序。     

西南地区农村家庭普通高中教育选择影响因素分析——基于四川省三台县的调查

本文以教育与经济发展理论为基础,通过对四川省三台县农村地区的家庭及其子女成员的数据资料的调查,对西南地区农村家庭普通高中教育选择的影响因素进行了分析和总结。