甲基丙烯酸甲酯悬浮聚合实验教学的改进

选用氢氧化镁为分散剂,甲基丙烯酸甲酯(MMA)为单体,进行悬浮聚合反应,研究了分散剂用量、引发剂用量、水和单体比、搅拌速度、反应温度及反应时间对聚合物珠粒大小、均匀程度和产率的影响。结果表明:与目前高分子实验教材普遍选用的以聚乙烯醇(PVA)为分散剂的悬浮聚合反应相比,以氢氧化镁为分散剂,具有操作简单、聚合时间短、体系稳定性高等优点,可代替原有的悬浮聚合反应实验,作为高分子化学实验的教学课程内容。     

Power grid redundant path contribution in system on chip (SoC) robustness against electromigration

The miniaturisation of integrated circuits leads to reliability issues such as electromigration (EMG). This well-known phenomenon is checked at design level by CAD tools. The conventional EMG check methods are based on electrical parameters. However, the wire physical degradation depends also on the interconnection network structure. In order to improve the EMG check methodologies, we propose an accurate method based on failure mechanism and chip power grid configuration. Indeed, the power grid offers redundant paths in case of void in main power supply path. The principle of our method is to take into account the contribution of these redundant paths in power grid lifetime assessment. These effects are validated by silicon ageing tests on structures designed in 28 nm Full Depleted Silicon on Insulator (FDSOI). These accelerated tests results have confirmed the lifetime gain due to the redundancy. These results provide perspectives for the relaxation of wire current limits and improve the chip design toward EMG.     

浅谈MOSFET产品失效分析及改善措施

阐述了MOSFET产品的应用前景，说明了其封装工艺流程及注意事项，通过对MOSFET电路常见失效现象的分析验证，探讨MOSFET产品的失效机理及其影响，对相应的失效现象制定合理的失效分析方案，确保有效查找失效的具体原因，并对失效原因从设计、工艺和材料选用等方面提出改善措施。     

X波段捷变频磁控管的研究

分析了捷变频磁控管在研制过程中关键零部件对磁控管性能的影响,并在设计方面给出了预防措施。     

Preconcentration of samples in sandwich tanks for continuous thin-layer chromatography

It is demonstrated that horizontai sandwich tank with two cover plates can be used to preconcentrate sample solutions. Narrow sharply-defined starting zones are obtained just outside the smaller cover plate when the series of spots of the sample solution are applied on the thin layer and predeveloped with a volatile solvent. After evaporation of the solvent, the whole area of the TLC-plate is covered with two plates and developed with a suitable solvent.     

诺基亚西门子软交换容灾方案的应用及改进

对诺基亚西门子软交换容灾方案和原理进行了深入研究和分析，并对方案进行了改进。对改进后的实际测试情况进行了总结，从而证明改进方案可以大大缩短倒换所需时长。保证了软交换出现紧急情况下业务能迅速的切换和恢复。     

基于CPLD控制的DDS数字频率合成器设计

介绍了ADI公司新一代DDS芯片AD9952和XILINX公司新一代CPLD产品XC2C128的主要性能，提出了用XC2C128作控制电路，由AD9952构成宽带、低相噪、低功耗数字合成频率源的设计方案，同时对如何提高DDS频谱纯度进行了探讨，给出了超宽带应用电路解决方案。     

Simultaneous estimation of Poisson means

In the simultaneous estimation of means from independent Poisson distributions, an estimator is developed which incorporates a prior mean and variance for each Poisson mean estimated. This estimator possesses substantially smaller risk than the usual estimator in a region of the parameter space and seems superior to other estimators proposed to estimate p Poisson means. It is indicated through two asymptotic results that, unlike the conjugate Bayes estimator, the risk of the estimator does not greatly exceed the risk of the usual estimator outside of the region of risk improvement.     

还原偶氮测定硝基苯方法中样品背景存在的问题及改进

对还原偶氮法测定水中硝基苯分析方法中样品背景等方面存在的问题,以及对分析测定产生的影响进行了较为深入的分析和研究;提出了测定方法的改进意见.并通过硝基苯环境标准样品的实际测定,对改进前后的方法进行了对比和验证,取得了满意的结果.     

印制板图形电镀针孔产生的因素探究

在印制电路板制作电镀过程中,电镀针孔是图形电镀生产过程中产生的不良缺陷之一,此缺陷严重影响了板件的一次合格率.本文通过对针孔产生的原因进行系统分析,识别产生原因,并有效解决问题,为PCB电镀制程改善提供参考.