基于速度阻尼力位切换DSP算法的引线键合机邦头设计

引线键合是半导体后道封装中重要环节,实现芯片与外部框架的电气信号连接。其中,键合邦头的力位控制是引线键合的关键。从应用角度出发,分析切换过程与影响力位切换的相关因素,设计了一种基于速度阻尼力位切换DSP算法的引线键合机邦头控制器。实验数据表明：在整个力位切换过程中,加力平稳,键合邦头在力位切换过程中的振动得到了很好的抑制,具有较高的应用价值。     

钌粉在不同温度下双向真空热压后的显微结构和晶体学演变

在温度为1050°C至1450°C、时间为2 h的条件下对钌粉进行了双向真空热压烧结。采用扫描电子显微镜(SEM)和X射线衍射(XRD)对烧结样品进行了分析。在1250°C烧结时,真空热压样品的相对密度达到理论密度的99.7%;当温度进一步升高,密度出现下降。在不同的烧结温度可以看到不同的晶粒和孔洞形貌。XRD数据表明在烧结过程中获得了(002)择优取向。随着烧结温度的增加残余应力有所减小。     

Study of nonionic surfactants on HVOCs removal from coacervate solutions using cocurrent vacuum stripping in a packed column

ABSTRACT

Cloud point extraction has been shown to be an effective technique to remove hydrophobic volatile organic compounds (HVOCs) from aqueous solution using nonionic surfactant. A cocurrent vacuum stripper is used to recover the surfactant in coacervate phase from extraction for economic viability. The solutions containing two series of aromatic and chlorinated HVOCs. Surfactants studied were alkyl phenol ethoxylates, secondary alcohol ethoxylates (AEs), and branched secondary AEs. From equilibrium measurements, the apparent Henry’s law constant (volatility) of the HVOCs in surfactant solution decreased with increasing HVOCs hydrophobicity due to solubilization of the HVOCs in micelles. The results showed that the mass transfer of HVOC decreases due to the solubilization enhancement of the HVOCs.     

Vacuum Technology Considerations For Mass Metrology

Vacuum weighing of mass artifacts eliminates the necessity of air buoyancy correction and its contribution to the measurement uncertainty. Vacuum weighing is also an important process in the experiments currently underway for the redefinition of the SI mass unit, the kilogram. Creating the optimum vacuum environment for mass metrology requires careful design and selection of construction materials, plumbing components, pumping, and pressure gauging technologies. We review the vacuum technology¹ required for mass metrology and suggest procedures and hardware for successful and reproducible operation.     

论商品商标翻译的原则与方法

从商标翻译的原则和方法两方面探讨了在商品包装设计中商标翻译的运用策略,以期达到正确、忠实、准确地翻译商标,增强商品竞争力,帮助企业取得良好经济效益。     

冷却速度对真空电弧熔炼CuCr25合金组织及性能的影响

采用真空电弧熔炼法制备CuCr25合金,随合金凝固时的冷却速度不同,合金的组织将发生很大变化,而不同组织对合金的性能特别是电击穿性能将产生不同的影响,必须选用一种最合适的冷却方式对熔炼后的合金进行冷却凝固.通过对不同冷却方式下合金的组织变化及其对耐电压强度影响的研究,确定水冷凝固法作为真空电弧熔炼CuCr25合金的主要冷却方式.     

无菌包装微生物安全性

讨论了在无菌包装中如何避免、监控及判定不良微生物的污染。     

A frequency domain technique for maintaining resonance condition during sine dwell vibration testing of packages

When a package undergoes progressive damage during a sine dwell vertical vibration test, its dynamic characteristics, such as stiffness and damping, will change. This will result in variation of its resonance frequency during a test. This paper demonstrates that tracking the resonance by feedback control of the excitation frequency during resonance dwell tests is essential. Furthermore, this paper shows the differences in the results obtained from dwell tests with uncontrolled and controlled excitation frequencies. A computer‐based resonance tracking system was developed and used together with a commercial vibration table to experimentally verify the benefits of such a technique. Copyright © 2000 John Wiley & Sons, Ltd.     

引进CBE模式 探索化工职业能力培养

ＣＢＥ模式是近年来广泛被北美国家采用的一种职业技术教育模式，贵州省化工学校于１９９８年引进该模式，对工业分析专业的相关课程进行教改。本文从ＣＢＥ模式的内涵到ＣＢＥ模式的引进实践阐述了化工职业能力培养的新途径。     

20万t/a PET装置真空系统的故障排查及处理

简单介绍了本装置三级真空喷射泵的工艺流程,对PET装置乙二醇蒸发器和三级喷射泵组成的真空系统出现故障的原因进行了分析、排查,通过加厚装置的保温系统和适当提高伴热系统的温度,避免了由于真空量不足造成的一次非计划停车的事故。