Design of Control Scheme for Variable Air Volume Air- conditioning System

The air quantity of variable air volume system for the rooms and the total air quantity of the system changes with the change of room load. Combined with the system composition in the laboratory, the paper determines the control scheme of the variable air volume system, that is, indoor temperature-control, indoor positive pressure control, air distribution static pressure control, air-supply temperature control and new air volume control. The dotted lines with arrows mean the output signals from the control unit to actuator, and the solid lines with arrows represent the input signals from the actuator to the control unit.

CMOS芯片键合失效分析与研究

通过对CMOS芯片引线键合过程中发生铝焊盘剥落和出现"弹坑"两种现象进行分析,明确了该类故障现象的发生是由于键合焊盘受到了不同程度的机械作用而产生的不同程度的损伤。对可能造成该类故障现象的因素进行分析,主要因素有:芯片自身存在结构薄弱或原始缺陷,键合材料、键合参数等匹配不佳,操作中引入的不当因素等。对引线键合的方式和原材料进行优化,选定自动金球键合工艺,并采用单一变量法和正交优化法对自动金球键合的工艺参数进行优化,给出了自动金球键合工艺参数优选范围。通过环境试验对CMOS芯片自动金球键合工艺进行了可靠性评价。