Effect of ultrasonic power and bonding force on the bonding strength of copper ball bonds

Copper wire, serving as a cost-saving alternative to gold wire, has been used in many high-end thermosonic ball bonding applications. In this paper, the bond shear force, bond shear strength, and the ball bond diameter are adopted to evaluate the bonding quality. It is concluded that the ef/~cient ultrasonic power is needed to soften the ball to form the copper bonds with high bonding strength. However, excessive ultrasonic power would serve as a fatigue loading to weaken the bonding. Excessive or less bonding force would cause cratering in the silicon.     

冷热饮水机分流阀注射模设计

根据分流阀的结构特点,介绍了分流阀注射模的主要结构,该结构解决了外螺纹侧向抽芯与塑件上小孔的4个方向抽芯问题,并就模具浇注系统的偏心问题的解决方法进行了说明     

再谈高速走丝线切割机断丝原因的分析及对策

针对高速走丝电火花线切割加工的断丝问题，从各个方面补充分析了线切割加工中的断丝原因及解决方法，这些方法能切实有效地减少断丝的发生。     

我国型钢生产技术进步20年及展望

按小型材、棒线材、中型材、轨梁和大型材分类 ,对 2 0年来我国在型钢生产领域的主要技术进步进行了总结 ,对其生产现状进行了分析 ,对其发展前景进行了展望     

Effects of CeF3 on properties of self-shielded flux cored wire

0 IntroductionSelf-shielded flux cored wire is a newly developedwelding material used without gas protection. Use of suchcored wires has grown rapidly in developed countriesbecause of the following advantages: simple use, goodwind resistance ability, lower cost resulted from highproductivity and strong desulfurization ability[1]. Self-shielded flux cored wires are preferred for on-site weldingsuch as ship and barge building, storage tank, bridge,offshore oil platform buildings and so on[2 -3].…     

高性能纤维的弯曲疲劳断裂研究

在自制弯曲疲劳装置上 ,对 3种高强对位芳纶及超高相对分子质量聚乙烯纤维 (Dyneema SK65 )进行双面弯曲疲劳试验。结果表明 ,Twaron 2 0 0 0弯曲疲劳寿命的自然对数与预加应力、弯曲角度呈线性关系 ,Dyneema SK65弯曲疲劳寿命明显长于对位芳纶 ,Twaron 2 0 0 0 ,Kevlar 12 9相近 ,都比Kevlar 2 9略长 ;高强型对位芳纶的弯曲疲劳断裂断口芯层呈现出“毛笔头”或“拔丝形”原纤化分裂形态 ,超高相对分子质量聚乙烯纤维弯曲疲劳断裂断口有明显的脆性折断形态 ,无原纤出现。     

望远镜专用PVC外装饰皮的开发应用

从生产用原材料、配方、生产工艺及影响因素等方面介绍了软质PVC在望远镜用外装饰皮中的应用,并进行了分析、探讨,提出了软质PVC在望远镜用外装饰皮中研制开发的看法与建议。     

Tasting green leaf volatiles by larvae and adults of Colorado potato beetle,Leptinotarsa decemlineata

Larvae and adults of the Colorado potato beetle,Leptinotarsa decemlineata (Say), are shown to have galeal gustatory cells that are highly sensitive to distillate of potato leaf extracts, (E)-2-hexen-1-ol, (E)-2-hexenal, and other saturated and unsaturated six-carbon alcohols. In larvae and adults, the sensory response patterns elicited by leaf homogenate, leaf distillate and a mixture of these two extracts differ in subtle ways. Beetle larvae feed most readily on Millipore disks treated with leaf homogenate and the mixture, but they did not feed on disks treated with leaf distillate. The differences in behavioral response and sensory input are used to derive a potential gustatory code that may stimulate different levels of feeding. This code may be disrupted by compounds present in nonhost leaves, thus leading to reduced feeding. Possible interactions of sapid leaf volatiles, amino acids, sugars, and potentially deterrent plant compounds are discussed.     

Different feeding and gustatory responses to ecdysone and 20-hydroxyecdysone by larvae of the silkworm,Bombyx mori

The feeding and gustatory responses to ecdysone and 20-hydroxyecdysone were investigated in the silkworm,Bombyx mori. 20-Hydroxyecdysone reduced feeding response strongly in fourth- and fifth-instar larvae, whereas ecdysone had no effect on feeding response. 20-Hydroxyecdysone stimulated the R receptor, the receptor to feeding deterrents, to a great degree. By contrast, ecdysone was much less effective for stimulating the R receptor. These results indicate that ecdysone and 20-hydroxyecdysone have different effects on feeding response due to different interactions with mouthpart chemoreceptors.     

用弯曲模型推导二组元复合材料杨氏模量新公式

用弯曲模型推导了适用于悬丝耦合弯曲共振法检测金属第二组元的杨氏模量的理论公式。通过实验数据计算。结果表明在两组元h2/h1≈1时与文献[2]的计算结果几乎接近，为用悬丝耦合弯曲共振法检测各种减振材料，陶瓷材料杨氏模量提供了理论公式；同时用改进后的弯曲模型推导出了适用于纤维复合材料横向杨氏模量的预测公式。