Failure analysis of leakage current in plastic encapsulated packages

Plastic encapsulated packages exhibit high leakage currents after a few hundred hours in the steam pressure pot test (SPP). The present study investigates two possible causes of leakage current. These are: (a) mold compound, (b) the polyimide tape used for co-planarity of lead frame fingers. The results of this study indicate that the leakage cur-rent is independent of the frame and is not caused by the mold compound. The data indicates that it is the ionic content and acrylic-based adhesive layer of the polyimide tape which cause the leakage current. To eliminate the leakage current, polyimide tape with low ionic content and non acrylic-based adhesive should be used. *Permanent address: School of Physics, Universiti Sains Ma-laysia, 11800 USM Penang, Malaysia.     

寒区水工混凝土破坏及防治措施

分析说明水工建筑物混凝土质量恶化的原因及防治措施。     

谈电视节目的制作方式

本文讨论了目前电视节目制作的两种方式,即电视影片和电视录像,井指出它们各自的优势及存在的问题。     

Investigations of nano- and macro-wear of magnetic tape head materials

The nano- and macro-wear characteristics of calcium titanate, single crystal ferrite and polycrystalline ferrite were investigated using nano-scratch testing and wear bar testing. Nano- and micro-indentations were made to determine nano- and micro-hardness, and nano-scratch testing was used to evaluate relative wear rates on the nano-scale. The macro-wear characteristics of the various head materials against metal particle tapes was investigated as a function of tape speed using wear bars mounted in a DLT tape drive. The micro-indentation method was used to investigate wear of the head/tape interface in a linear tape drive. The results from nano- and macro-wear tests were analysed and correlated with the microstructure of the materials.     

热熔压敏胶,用于OPP包装带优先技术

从包装带的历史，成本，生产率，性能（使用温度、对回收纸板粘合性、对非极性基材粘合、涂胶量控制），外观，环境污染问题等方面论证热熔压敏胶作为优先技术，应用于OPP包装带。     

基于高斯扩散模型的催泪弹气溶胶烟雾非致命效能仿真

催泪弹是一种非致命防暴弹。为研究其非致命效能大小,以武警RS97-2型催泪弹为研究对象,应用高斯扩散模型研究了催泪弹气溶胶烟雾的扩散过程。分析了烟雾扩散时西埃斯(CS)催泪剂浓度和烟雾半径的变化规律。用Matlab软件编制的程序进行了仿真计算,得出以催泪弹气溶胶烟雾扩散的有效作用区域作为其非致命效能大小的衡量指标。结果表明,在风速为2m·s~(-1)时,一枚催泪剂装药为20g催泪弹的气溶胶烟雾有效作用区域可达453.7m~2。     

一种新型H级少胶粉云母带的研制

该H级少胶粉云母带采用改性环氧树脂为胶粘剂,无碱玻璃布浸渍树脂后先后分别复合粉云母纸和聚酰亚胺薄膜(耐电晕处理或不耐电晕处理),经烘焙、收卷、分切、包装而成的一种电机主绝缘材料。探讨了该材料的常规电气性能及与不同类型的浸渍树脂配套绝缘性。     

工艺过程中生瓷带收缩问题研究

HTCC/LTCC的工艺过程中经常会出现生瓷带收缩现象,由此现象引起的系列工艺问题众多,尤其对于多层互连结构的产品影响很大,而一些工艺环节会加重生瓷带收缩现象出现的频率、收缩的程度。文章对于生瓷带收缩现象的产生原因进行了较为详细的分析与阐述,同时针对生瓷带收缩问题采用生瓷带预处理工艺,并着重对不同的预处理工艺进行试验对比。不同的生瓷带预处理工艺各有利弊,可以根据产品的各自特点综合考虑,采用合适的工艺方法对生瓷带收缩问题加以解决。     

商用飞机热塑性聚氨酯防潮胶带的研制

探究了国外某产品与军用防腐膜HP8714在关键技术指标水蒸气透过量及12 s垂直燃烧的性能,并以乙酸乙酯EAC为胶黏剂溶剂研究了胶黏剂种类及含量对防潮胶带性能的影响。结果表明,HP8714的热塑性聚氨酯原料A198FR可作为高性能阻燃热塑性聚氨酯防潮胶带的树脂原料,并以A198FR为树脂原料,确定压敏胶YY16为最适宜胶黏剂,优选YY16/EAC配比为75/25,并通过第三方测试验证所有指标。     

纸的断裂韧性及其与纤维长度的关系

介绍了用断裂基功的概念测定纸张断裂韧性的新方法。并用此法研究了纤维长度对断裂韧性的影响，表明纸的断裂韧性与纤维长度几乎成直线关系；断裂韧性对纤维长度的依赖性比撕裂和抗张强度大。