高密度印制板组件离心清洗工艺技术研究

针对低架空高度、高密度封装BGA和CSP底部难以清洗干净的难题,将离心清洗工艺技术应用于PCBA的清洗中.探讨清洗溶剂选择原则,研究离心清洗工艺原理,设计和优化了离心清洗工艺流程,设置了离心清洗工艺参数,分析以上因素对高密度印制板组件清洗效果的影响规律.清洁度检测结果表明:清洗溶剂选择正确,清洗工艺流程合理,离心清洗工...     

集成电路组装后的清洗与免清洗技术

从超声波清洗用清洗溶剂,特别是替代消耗臭氧层物质的氯化氟代碳（CFC）清洗溶剂等方面介绍了集成电路的清洗技术;还介绍了集成电路的免清洗工艺技术, 使用免清洗工艺技术对各道关键工序的控制及采用免清洗技术的主要优势。     

PCBA全自动清洗设备的选型

主要论述了PCBA清洗设备的种类,着重论述了全自动水清洗设备的结构、功能(喷淋技术和清洗方式)及性能(清洁度监测、清洗温度及时间、漂洗水量及次数、喷淋压力和溶剂回流延时),并对市场上各类型的水清洗设备进行了关键指标的比较,为研究院所小批量多品种PCBA的高标准清洗选择合适的清洗机提供一个参考.     

电子工业中的免清洗技术

在电子工业替代ＣＦＣ清洗的技术有：．溶剂清洗；利用非ＣＦＣ溶剂清洗．水清洗：利用去离子水或水中加皂化剂清洗．半水清洗：利用溶剂和水共同清洗．免清洗：利用免洗助焊剂，焊后不清洗免清洗具有节约费用，节约清洗设备，无污染等优点，引起普遍重视。免清洗工艺的核心是选择好的免洗助焊剂和合适的涂布方式，一种好的助焊剂应具有下面的性能：．焊后无残留物．焊后无残留物．焊后板面干燥．不腐蚀；．具有在线测试能力．不形成     

论半水清洗

清洗是表面贴装技术中的一个重要环节。但是目前发现清洗工艺中广泛使用的CFC对大气臭氧层具有破坏作用,所以人们正大力开发CFC的替代物。在替代物的开发中,一种新型的清洗方法——半水清洗脱颖而出。本文着重论述了半水清洗中所采用的溶剂、工艺和设备,并对其可行性、优缺点进行了分析,最后还就半水清洗与其他替代方法进行了比较。     

IF2005系列免清洗助焊剂在无铅工艺中的应用

IF2005系列免清洗助焊剂是北京晶英免清洗助焊剂有限公司(INTERFLux)的主导产品。它是一种低固体含量的免清洗助焊剂，在焊接过程中焊剂中的固体成分能完全挥发，极大地保证了高尖端电子产品的可靠性。这种不含卤素的助焊剂符合．Bellcore和IPC标准，且通过美国军标(MIL—F-14256F)的认证，一直受到广大使用客户的好评.     

无铅焊料用免清洗助焊剂的研究

用润湿力试验和铺展试验来确定活性组分和溶剂,研制了一种以醇作为溶剂的免清洗助焊剂.结果表明:该助焊剂选用复合有机酸和有机胺作为主要活性成分,有机酸的配比为1:2时有很好的助焊效果,选择醇类作为溶剂对有机酸的溶解性好;该免清洗助焊剂助焊性能良好,腐蚀性小,焊后可以免于清洗.     

溶剂清洗设备缺陷的改进

本文根据使用经验对溶剂清洗设备的安全、环保等方面存在的缺欠提出了可行的改进方案，使溶剂清洗设备的结构趋于完善，并提供了安全、环保等方面的保障，既保护了操作人员的身体健康，又避免了对环境的破坏。     

激光清洗技术在雷达T/R组件制造中的运用

要提高雷达T/R组件的可靠性,清洗工艺是非常重要的工艺步骤。但是,超声波清洗和汽相清洗等很多清洗工艺都有很多的缺点,使用的溶剂污染环境,破坏大气层,对人体有害,而且还会对组件中的电路或芯片造成损伤。激光清洗工艺有环保和无损伤的优点,而且能有效地清除组件中的氧化物、有机污染物和各种细小的颗粒等。可以预测,激光清洗必将在雷达T/R组件的制造中发挥越来越重要的作用。     

变电站二次设备带电清洗关键点及溶剂性能分析

变电站二次设备带电溶剂清洗是近几年发展起来的清洁维护技术,比传统的清洁方法存在的优点是:设备不停电、高效,解决了停电维护造成供电紧张的问题。带电工作的关键点是冲洗溶剂的性能及冲洗方法,笔者根据多年二次设备冲洗的经验,总结出二次设备清洗的注意事项及影响溶剂性能的成分配比。     

新风量对室内VOCs浓度分布影响的模拟分析

本文分析了影响室内空气品质的污染物VOCs(挥发性有机化合物)的来源及危害，介绍了对其进行控制的几种方法，并用数值模拟的方法研究了新风量对室内VOCs浓度的影响。     

非接触光镊法研究混合液体黏滞系数的组分关系

利用光镊技术对一组质量百分比含量不同的乙醇水溶液在30oC下的黏度进行了测量,其结果与理论估算的一致,二者之间的偏差为10%左右;此外,得到的黏度随乙醇含量的变化规律与20oC、40oC时的相同。验证了基于光镊非接触操控方法在易挥发液体及其混合溶液黏度测量的实用价值。     

Composition of pulsed-laser-deposited Y-Ba-Cu-0 and Ba-K-Bi-O thin films

The composition of pulsed-laser-deposited Y-Ba-Cu-O and Ba-K-Bi-O thin films is shown to be strongly affected by target conditioning, gas pressure, and target-substrate distance. For both compounds, ablation from a freshly sanded target surface results in films with an excess of the more volatile elements. The concentration of these volatile elements in the films decreases until the system reaches a steady state after sufficient ablation from the target. Y-Ba-Cu-O film composition is also affected by oxygen pressure and target-substrate distance. Increasing pressure or distance results in relative copper and barium depletion in the central region of deposition, presumably due to differences in the efficacy of oxygen in scattering the different elements. This relationship between pressure, distance, and composition is shown to be significant for the growth of optimal superconducting Y-Ba-Cu-O thin films. The composition of Ba-K-Bi-O is also affected strongly by background gas pressure. Ba-K-Bi-O deposited in vacuum is potassium deficient in the film center. A background argon pressure of 1 Torr, however, increases the potassium concentration and results in films with uniform composition over a broad area. We argue that this effect is significant in explaining a successful growth method for superconducting Ba-K-Bi-O films.     

Solvent-free microwave extraction : an innovative tool for rapid extraction of essential oil from aromatic herbs and spices.

A relatively simple apparatus is described for extracting essential oils from aromatic plant material by atmospheric solvent-free microwave extraction (SFME) without the addition of any solvent or water. Isolation and concentration of volatile compounds were performed by a single stage. The product solutions of volatile compounds were directly analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The essential oils fiom aromatic herbs (basil, crispate mint, thyme) and spices (ajowan, cumin, star anise) extracted by SFME for 30 minutes and I hour, were similar to those obtained by conventional hydro-distillation (HD)for (respectively) 4 and 8 hours. Substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes hydrocarbons are present in the essential oils of the aromatic plants extracted by SFME in comparison with HD. Solvent-free microwave extraction is clearly advantageous to conventional distillation in terms of rapidity, efficiency, cleanliness, substantial saving of energy, and is environmentally friendly.     

一种光离子化检测系统的设计与实验研究

开发了基于高灵敏度电离室检测技术的通用型光离子化检测器.对光离子化检测器的核心部分进行了分析与设计,着重阐述了系统设计的原则、结构及特性.利用配制的标准气体和PID检测仪进行联测优化和线性度测量,并给出了仪器实验性能的实例.证明了该光离子化检测系统的确能够检测特定极低浓度的有机化合物,并且可以区分不同梯度的同种样品.     

光电离/离子迁移谱技术研究

为了实现仪器的实时在线监测,利用能量为10.6 eV的紫外光灯取代传统础Ni放射性电离源,自主研发出便携、快速、高灵敏的光电离/离子迁移谱仪.紫外光灯为直流供电,避免了放射性物质严格的操作规程,并且实现了易制毒化学品有机物分子的软电离.最近的实验结果表明,在列出的23种违禁物品中,13种以上可以得到快速有效的鉴别,检测时间在几秒以内,检测下限可以达到PPb量级,其中挥发性成分的检测结果尤为显著.     

On Using the Volatile Mem-Capacitive Effect of TiO<Subscript>2</Subscript> Resistive Random Access Memory to Mimic the Synaptic Forgetting Process

In this work, we report on mimicking the synaptic forgetting process using the volatile mem-capacitive effect of a resistive random access memory (RRAM). TiO₂ dielectric, which is known to show volatile memory operations due to migration of inherent oxygen vacancies, was used to achieve the volatile mem-capacitive effect. By placing the volatile RRAM candidate along with SiO₂ at the gate of a MOS capacitor, a volatile capacitance change resembling the forgetting nature of a human brain is demonstrated. Furthermore, the memory operation in the MOS capacitor does not require a current flow through the gate dielectric indicating the feasibility of obtaining low power memory operations. Thus, the mem-capacitive effect of volatile RRAM candidates can be attractive to the future neuromorphic systems for implementing the forgetting process of a human brain.     

Modeling and closed-loop control of hypnosis by means of bispectral index (BIS) with isoflurane

A model-based closed-loop control system is presented to regulate hypnosis with the volatile anesthetic isoflurane. Hypnosis is assessed by means of the bispectral index (BIS), a processed parameter derived from the electroencephalogram. Isoflurane is administered through a closed-circuit respiratory system. The model for control was identified on a population of 20 healthy volunteers. It consists of three parts: a model for the respiratory system, a pharmacokinetic model and a pharmacodynamic model to predict BIS at the effect compartment. A cascaded internal model controller is employed. The master controller compares the actual BIS and the reference value set by the anesthesiologist and provides expired isoflurane concentration references to the slave controller. The slave controller maneuvers the fresh gas anesthetic concentration entering the respiratory system. The controller is designed to adapt to different respiratory conditions. Anti-windup measures protect against performance degradation in the event of saturation of the input signal. Fault detection schemes in the controller cope with BIS and expired concentration measurement artifacts. The results of clinical studies on humans are presented.     

Solventless Polymerization to Grow Thin Films on Solid Substrates

We report on the formation of polymeric thin films on a solid surface using gaseous monomers. The process consists of adding catalysts on the surface of a solid substrate and polymerizing volatile monomers at the gas/solid interface, or directly using the vapors of the catalyst and the monomers to selectively form polymers inside the microchannels. The morphology and properties of these thin films depend on the concentration of catalysts, the time of exposure to the monomers, and the type of the monomers, which can be easily controlled at the molecular level. This solventless process can be used for a range of applications.     

NH3 对二甲苯光氧化形成二次有机气溶胶的影响

二甲苯是一种重要的人为源 VOC, 也是城市地区 SOA 的重要前体物。二甲苯光氧化形成的 SOA 受多种环 境因素影响, 而 NH3 对该反应形成的 SOA 生成产率及反应机制的影响尚不清楚。基于室内烟雾箱模拟系统, 探讨了 NH3 对二甲苯光氧化形成 SOA 质量浓度、物理特性及化学组成的影响。研究表明, 在低浓度条件下, NH3 对二甲苯 光氧化生成 SOA 具有明显的促进作用, 结合气溶胶质谱结果发现 NH3 促进醛酮类物质进入颗粒相以及含氮有机物的 生成是导致 SOA 质量浓度增加的主要原因。此外, NH3 能够提高邻二甲苯生成 SOA 的吸光度, 但是对对二甲苯无明 显影响。分析表明, 相较于对二甲苯, 邻二甲苯光氧化会生成大量醛类物质, NH3 与醛类发生美拉德反应是导致 SOA 吸光性增加的主要原因。