蒸发因素对高密度焦平面铟凸点制备影响研究

高一致性、高深宽比凸点制备是高密度红外焦平面制造的关键技术之一。以10 μm间距铟凸点阵列为研究对象,通过提取铟凸点高度、顶部直径、生长速率纵横比和铟膜粗糙度等参数,结合薄膜形核生长理论,深入分析热蒸发过程中关键因素对铟凸点生长的影响,为更小间距铟凸点制备提供理论与技术参考。实验结果表明,沉积速率和基底温度对铟凸点生长的影响具有两面性：一方面,高沉积速率和低基底温度会细化铟膜晶粒,有利于沉积高均匀性铟凸点阵列。基底温度下降了45 K,铟凸点高度非均匀性从15.4%降低到6.6%,铟凸点顶部直径范围差下降了0.9 μm。沉积速率增加了21 Å/s后,铟凸点高度非均匀性从11.8%降低到6.6%,铟凸点顶部直径范围差下降了0.4 μm。另一方面,高沉积速率下的动理学粗糙化影响比重增加,铟薄膜粗糙度随沉积速率变化趋缓。同时高沉积速率和低基底温度下的光刻孔缘铟向四周扩散的能力减弱,继续降温后铟层横向生长速率从3.4 Å/s升至4.1 Å/s,光刻孔加速闭合不利于高密度、高深宽比、高均匀性铟凸点的生长制备。

     

Application of the adjoint multi-point and the robust optimization of shock control bump for transonic aerofoils and wings

A shock control bump (SCB) is a flow control method which uses a local small deformation in a flexible wing surface to considerably reduce the strength of shock waves and the resulting wave drag in transonic flows. Most of the reported research is devoted to optimization in a single flow condition. Here, both equally and variably weighted multi-point optimization and a robust adjoint optimization scheme are used to optimize the SCB. The numerical simulation of the turbulent viscous flow and a gradient-based adjoint algorithm are used to find the optimum location and shape of the SCB for two benchmark aerofoils. A multi-point optimization method under a constant-lift-coefficient constraint is implemented to find the optimum design of a two-dimensional (2D) SCB and it is observed that the general results are similar to other optimization algorithms. To show that these results are extendable to real three-dimensional (3D) cases, a 3D bump model with 11 parameters is introduced, and it is optimized using both single- and multi-point optimization procedures. Although the 3D flow structure involves much more complexity, the overall results are shown to be similar to the 2D case.     

抗冲击车路能量收集减速带设计与自供能交通管控

车辆滚压道路会产生大量机械能,将这些能量收集为交通环境中小型机电系统供电,实现自供能交通状况监测和交通管控等,使交通系统更加安全、有序、高效地运行;并且绿色环保,有益于我国“双碳”目标的实现。提出一种用于单向车道的抗冲击车路能量收集减速带(Anti-impact vehicle-road energy harvesting bump,AVEHB)。通过“顺势运动”吸纳车辆滚压能量,可以减少对器件和路基的冲击损伤,使更多滚压激励用于做功。抗冲击对比试验验证了该设计的优点。基于AVEHB工作原理,建立机电耦合动力学模型并进行试验验证。试验结果还显示,在车速50 km/h时,AVEHB最大输出电压和功率分别为146.7 V和143.47 W。探索了自供能车速监测及行人主动安全警示等应用,验证了AVEHB具有为交通环境中机电系统供电的潜力。根据供电需求合理设置AVEHB阵列,可以为智慧交通系统提供便捷、可持续、绿色环保的零碳电力。     

凸点下金属层湿法刻蚀与凸点底切的控制

介绍了电镀凸点封装工艺流程和其中有关金属层湿化学刻蚀的问题.通过槽式批量和单片机刻蚀相应的UBM(凸点下金属层)的均匀度、刻蚀速率和凸点底切的对比,结果显示单片湿法刻蚀机刻蚀均匀度小于5%且片与片之间刻蚀速率差异小于2%,以及凸点底切小于2μm.槽式刻蚀均匀度较差,一般会大于20%,同时同一批次片与片之间刻蚀速率差异也较大,实验显示超过10%,且刻蚀后凸点底切较深.因此采用单片机进行UBM金属刻蚀可以较好的控制刻蚀过程和提高产品的良率.     

基于田口法的高密度倒装微铜柱凸点热失效分析

采用有限元模拟法,分析在热循环载荷条件下高密度倒装芯片封装微铜柱凸点的失效行为,并以微铜柱凸点的最大累积塑性应变能密度作为响应,采用3因素3水平的田口正交试验法分析倒装芯片封装的主要结构参数和材料属性对其热失效行为的影响.结果表明,距离封装中心最远处的微铜柱凸点是封装体中的关键微凸点,热疲劳导致的裂纹易在该微铜柱凸点的基板侧焊料外侧形成.底部填充胶的线膨胀系数对微铜柱凸点热失效的影响最大,影响适中的是底部填充胶的弹性模量,最弱的是芯片厚度.     

Strength of titanium fillet welded joints

To improve the quality of a joint composed of metallic microstructural parts, a novel resistance brazing method called the ‘two-step resistance brazing method’ has been developed. In this method, filler metals plated on the surface of base metals are butted and alloyed due to the Joule's heat by performing two-step energizing. In this study, the numerical simulation of the joining process for the two-step resistance brazing method has been carried out. A mathematical formulation and corresponding calculation scheme, which is derived from using the control-volume method, are developed for a model based on contact resistance between the filler metals plated on the surface of the base metals, and transient two-dimensional heat conduction with the Joule's heat generation. The calculated result, based on a base metal of type 304 stainless steel and plated filler metals of gold and copper, is discussed and compared with experimental data.     

逆断层不同倾角对采场冲击地压的诱导分析

归纳了易造成冲击地压发生的主控参量,分析了断层倾角对冲击效应的力学机理,建立了逆断层简化模型,研究了不同断层倾角条件下的应力场、能量场、顶板下沉量等诱冲因素对冲击地压的基本作用规律。研究表明:上盘开采时,断层倾角小于45°的工作面超前支承压力峰值、弹性能峰值及顶板下沉量随断层倾角的增大而增大,大于45°时随断层倾角的增大而减小;下盘开采时,工作面超前支承压力峰值随断层倾角的增大而减小,且断层倾角为60°及75°时,工作面超前支承压力峰值前移,增加了冲击危险性;断层倾角大于45°的工作面前方弹性能峰值及顶板下沉量随断层倾角的增大而减小,小于45°的随断层倾角的增大而增大。无论上盘或下盘开采,断层区域弹性能及垂直应力都随着断层倾角的增加而增加。总体而言,断层倾角对下盘开采影响比上盘大。     

巨厚煤层应力集中诱发冲击矿压的作用机理

针对千秋煤矿21201工作面高地应力、巨厚、易燃复杂地质条件下冲击矿压频发的现状,采用FLAC3D软件模拟了工作面超前支承应力与相邻工作面采空区侧向支承应力叠加后形成动态应力场的变化规律.结果表明,在工作面前方局部区域产生3.3倍于原岩应力的垂直集中应力,在较高的动态集中应力作用下,煤体聚集了大量的弹性能,且该区域附近形成变化较大的错动剪应力,一定程度上加剧煤体破坏而引发冲击矿压.     

综放面过上分层终采线冲击地压危险性分析

综放工作面过上分层终采线时容易发生冲击地压现象,综放面接近上分层终采线时,前方煤体可看成是煤柱,可作为煤柱型,中击地压来分析,煤柱型冲击的主要影响因素有煤层的刚度和顶板岩层的刚度,具体反映在煤层的强度和冲击倾向性、顶板的来压和加速运动等。采用改变煤体物理力学性质的办法,可以防治煤柱型冲击地压的发生。东滩煤矿两个综放面过上分层终采线工作面的监测结果、治理效果说明了此冲击地压现象。