Effectiveness of a hardware-based approach to detect resistive-open defects in SRAM cells under process variations

Resistive-open defects in Static Random Access Memories (SRAMs) represent an important challenge for manufacturing test in submicron technologies as they may be masked by process variations, which in turn increases the number of test escapes. This paper evaluates the effectiveness of a hardware-based test approach that compares the current consumption of neighboring SRAM cells to detect resistive-open defects. The proposed approach is validated and its fault detection capabilities are analyzed for different defect sizes and taking into account process variations effects. Finally, the paper provides an evaluation of the minimum detectable resistive-open defect size for the proposed hardware-based approach under process variations effects.     

Development and Properties of High Density Polyethylene (HDPE) and Ethylene‐Vinyl Acetate Copolymer (EVA) Blend Antioxidant Active Packaging Films Containing Quercetin

The antioxidant quercetin was incorporated into high density polyethylene (HDPE) and ethylene‐vinyl acetate copolymer (EVA) films by flat compression. The mass ratio of HDPE : EVA was 65 : 35, and the amount of quercetin in the films was 0.74% (wt%) and 1.23%, respectively. The method of manufacturing the films achieved a high quercetin retention rate. The addition of quercetin did not significantly modify the thermal stability or the oxygen barrier of the films, while the water vapour barrier was weakened to some extent. Release of quercetin from the active antioxidant films into 50% ethanol (simulant for high alcohol containing products and milk as well as some dairy products) and 95% ethanol (simulant for fatty foods) at 37°C was periodically measured by HPLC over 45 days. The diffusion of antioxidant followed Fick's law. In 50 and 95% ethanol, the release content of quercetin was 70 and 10%, respectively, the diffusion coefficient (D) was 10^?13 and 10^?15 m²/s, and the partition coefficient (K) was 44 and 5863, respectively. The films showed a good release profile and could be used for the protection of foods. Copyright © 2014 John Wiley & Sons, Ltd.     

On the impact of anemometer size on the velocity field in a closed wind tunnel

In the present paper, experimental and numerical investigations of the flow around different types and sizes of anemometers are presented and discussed.The measurements of the flow field at different distances upstream of the anemometer are performed with a laser Doppler Anemometer. The computational results are in good agreement with the experimental ones since the observed deviations are of the same order of magnitude. These results show that anemometers may induce a strong distortion of the velocity field, even far upstream of the anemometer. This distortion has to be taken into account in the anemometer calibration field to yield reliable and consistent measurements.     

An improved empirical wavelet transform method for rolling bearing fault diagnosis

Empirical wavelet transform (EWT) based on the scale space method has been widely used in rolling bearing fault diagnosis. However, using the scale space method to divide the frequency band, the redundant components can easily be separated, causing the band to rupture and making it difficult to extract rolling bearing fault characteristic frequency effectively. This paper develops a method for optimizing the frequency band region based on the frequency domain feature parameter set. The frequency domain feature parameter set includes two characteristic parameters: mean and variance. After adaptively dividing the frequency band by the scale space method, the mean and variance of each band are calculated. Sub-bands with mean and variance less than the main frequency band are combined with surrounding bands for subsequent analysis. An adaptive empirical wavelet filter on each frequency band is established to obtain the corresponding empirical mode. The margin factor sensitive to the shock pulse signal is introduced into the screening of empirical modes. The empirical mode with the largest margin factor is selected to envelope spectrum analysis. Simulation and experiment data show this method avoids over-segmentation and redundancy and can extract the fault characteristic frequency easier compared with only scale space methods.

     

聚（甲基）硅氧烷/聚羟基丁酸酯/聚己内酯复合膜的制备及性能表征

将2 %（质量分数,下同）聚（甲基）硅氧烷（PMSQ）添加到不同比例的聚羟基丁酸酯（PHB）/聚己内酯（PCL）体系（25∶75、50∶50、75∶25）中,并以溶液浇铸法制备薄膜,研究PMSQ对PHB/PCL薄膜力学及理化性能的影响。结果表明,PMSQ对PHB25/PCL75的改善效果最好,其断裂伸长率从22.45 %提升至70.83 %,提升了3.15倍;FTIR光谱显示PMSQ的甲基（—CH₃）吸收峰消失,PHB/PCL体系中C＝O吸收峰增强,表明PHB和PCL接枝到PMSQ微球上;PMSQ的加入降低了PHB和PCL颗粒的粒径尺寸,同时PHB和PCL相分离现象得到改善,相容性提高;PMSQ的加入限制了PHB和PCL分子链的运动,破坏了PHB和PCL在空间上的规整性,结晶度降低;PMSQ的加入提高了所有比例的PHB/PCL体系的起始降解温度,同时提高了PHB和PCL的热稳定性,改善程度与两种组分比例相关。     

TFT-LCD产业中GOA单元不良的研究

通过对TFT-LCD制造过程中GOA单元不良原因的研究,提出了改善GOA单元不良的方法。分析表明静电放电(ESD)的发生在于电容瞬间释放的电流过大,导致过细的金属线熔化;沟道桥接和开裂的发生在于显影效应,显影方向以及图案密度,导致局部区域沟道光刻胶厚度偏厚和偏薄。采用静电分散释放的连线设计,ESD的发生率从5.4%降低到0.04%以下。GOA单元两侧增加测试图样(Dummy Pattern)的设计防止沟道桥接的发生,减压干燥(VCD)抽气曲线的调整和软烘(Soft Bake)底部温度的优化措施防止沟道开裂的发生,沟道桥接和开裂的发生率从13.4%降低到1.22%以下。     

基于非线性预测滤波算法的疲劳裂纹扩展预测

针对传统Paris疲劳裂纹扩展模型预测精度低、无法考虑裂纹扩展过程中各种不确定因素影响的问题,提出一种基于非线性预测滤波算法的疲劳裂纹扩展预测方法。使用基于Paris公式的状态空间方程表征裂纹扩展过程,采用基于Lamb波的监测技术构建观测空间方程,利用实时观测信息修正模型预测值。最后通过Q235钢试件的单边疲劳裂纹扩展实验验证了该预测方法的有效性。实验结果表明,非线性预测滤波算法在疲劳裂纹扩展预测中可以有效地修正Paris公式的预测误差,其预测精度高于扩展卡尔曼滤波和粒子滤波算法的预测精度,同时算法效率较粒子滤波算法有明显提高。     

基于改进卷积神经网络的燃气调压器故障识别研究

针对传统故障识别方法不仅过分依赖专家经验对故障特征进行提取且识别准确率不高的问题,在深度学习理论基础上,提出了一种将一维卷积神经网络与SVM分类器相结合的改进深度卷积神经网络,实现调压器“端到端”的故障识别。首先,介绍了传统卷积神经网络结构;其次,将改进后的一维卷积神经网络与SVM相结合,提出了基于1-MsCNN-SVM算法的调压器故障识别模型,并对模型的组成部分进行了介绍;然后,通过对比实验确定了模型的卷积核长度和卷积层组数;最后,为验证模型的有效性,基于燃气调压器故障数据集,开展了燃气调压器故障识别研究。研究结果表明,改进后的1-MsCNN-SVM算法故障识别准确率高达99.20%,模型具有较好的分类准确率。     

力传感器关键性能参数自动标定系统

针对力传感器的线性度、重复性、迟滞等关键性能参数的标定要求,提出了将虚拟仪器技术与数据采集技术运用于力传感器自动连续标定的方案,系统由力传感器、信号调理器、数据采集卡、力加载装置、上位计算机、系统软件6部分组成.开发的系统软件能够实现连续的数据采集、数据分析、数据显示.力传感器自动连续标定按照JJG144-2007《标准测力仪》计量校准,结果表明本装置的测力精度为1级.本项目的成功实施为力传感器的动态连续标定提供了新的技术手段.     

电梯导轨校准机器人力位控制研究

针对电梯导轨校准机器人校准电梯导轨时,校准精度低和校准力不可控等问题,提出一种基于改进的粒子群-模糊PD(PsoFuzzyPD)的电梯导轨校准机器人力位控制方法。首先,根据力位控制需求设计了电梯导轨校准机器人的整体控制框架;其次,设计了基于改进的粒子群-模糊PD控制器作为机器人力位控制器的内环控制器;最后,根据机器人的力控制需求设计了阻抗控制器、sigmoid函数的阻抗控制判别模块和期望力控制模块。仿真结果表明,所提方法的力控响应超调更小,震荡更少,笛卡尔空间的轨迹跟踪偏差也更小,可以有效控制导轨校准力和导轨校准精度,在电梯导轨安装领域拥有很好的推广应用价值。