Dynamic Power Supply Current Testing of CMOS SRAMs

We describe the design and implementation of a dynamic power supply current sensor which is used to detect SRAM faults such as disturb faults as well as logic cell faults. A formal study is presented to assess the parameters that influence the sensor design. The sensor detects faults by detecting abnormal levels of the power supply current. The sensor is embedded in the SRAM and offers on-chip detectability of faults. The sensor detects abnormal dynamic current levels that result from circuit defects. If two or more memory cells erroneously switch as a result of a write or read operation, the level of the dynamic power supply current is elevated. The sensor can detect this elevated value of the dynamic current. The dynamic power supply current sensor can supplement the observability associated with any test algorithm by using the sensor as a substitute for the read operations. This significantly reduces the test length and the additional observability enhances defect coverages.     

乙酰化香蕉淀粉的特性

通过与玉米淀粉比较,乙酰化香蕉淀粉的灰分、蛋白质、脂肪含量均比乙酰化玉米淀粉高.乙酰化香蕉淀粉糊的透明率在低温下出现较小的退化趋势,但常温下淀粉糊的透明率较高且有较好的稳定性.在较高温度下,乙酰化香蕉淀粉的持水能力比原淀粉高.乙酰化作用增加淀粉的溶解度和膨胀率.乙酰化作用也增加了香蕉淀粉糊的粘度值.     

C NMR study of the heterogeneity of the carrageenan from Rissoella verruculosa (Bert.) J.Ag. (Rhodophtya)

The co-existence of ω and -type polymers in the carrageenan system of Rissoella verruculosa led us to investigate the possible precursors for these structures. No highly sulphated carrageenan similar to what has been reported as precursor of most carrageenan was found. Isolation of a third component, β-carrageenan, is reported. Fractionation by DEAE chromatography shows that this latter polymer always coexists with ω but is never found in the fractions containing . The significance of this co-existence, as a preliminary approach to establish biosynthetic relationships between these different carrageenans, is discussed.     

Testing of static random access memories by monitoring dynamic power supply current

This article presents a correlation between dynamic power supply current and pattern sensitive faults in SRAMs. It is shown that the dynamic power supply current provides a window for observing the internal switching behavior of the memory cells. Switching of the logic state of a memory cell results in a transient current pulse in the power supply rails. A new current-testable SRAM structure is presented which can be used to isolate normal current transients from those resulting from pattern sensitivity. The new structure differs from traditional SRAM structures only in the way that power is distributed to the cells. The new structure allows for very high coverages of disturb-type pattern sensitivity using a simple algorithm of length 5n where n is the number of cells.     

香蕉葡萄糖浆的制备

研究用香蕉提取淀粉来制备葡萄糖浆。香蕉淀粉在抗高温α-淀粉酶的水解下可得麦芽糊精。香蕉麦芽糊精在淀粉葡萄糖苷酶和支链淀粉酶的作用下,经60℃,24h糖化后可制得葡萄糖浆。结果表明:香蕉葡萄糖浆和一般商用葡萄糖浆的化学和物理特性基本相同,但前者的颜色更清晰,适宜于食品工业的应用。     

Speed control of automotive diesel engines

This paper deals with Diesel engine control. More precisely, a model-based approach is considered to stabilise engine speed around a defined value. The model taken into account is nonlinear and contains explicitly the expression of fuel conversion efficiency. In general in the literature, this experimentally obtained quantity is modelled with either a polynomial or an exponential form (see for instance Younes, R. (1993). Elaboration d’un modèle de connaissance du moteur diesel avec turbocompresseur à géométrie variable en vue de l’optimisation de ses émissions. Ecole Centrale de Lyon; Omran, R., Younes, R., Champoussin, J., & Outbib, R. (2011). New indicated mean effective pressure (IMEP) model for predicting crankshaft movement. Energy Conversion and Management, 52, 3376–3382). This paper focuses on engine speed feedback stabilisation when fuel conversion efficiency is modelled with an exponential form, which is more suitable for automative applications. Simulation results are proposed to highlight the closed-loop control performances.     

从胡萝卜中提取淀粉的试验

尝试从秘鲁胡萝卜中提取淀粉,并将其理化性质与木薯淀粉进行了比较。结果显示,胡萝卜淀粉含量较高,与木薯淀粉的理化特性相似;其形态为球形和破鸡蛋壳颗粒状,其直径大小为4～26μm。     

Neural networks for real‐time nonlinear control of a variable geometry turbocharged diesel engine

New engines are submitted to emission standards that are becoming more and more restrictive. Diesel engines are typically equipped with variable geometry turbo‐compressor, exhaust gas recirculation system, high‐pressure common rail system and post‐treatment devices in order to meet these legislative requirements. Consequently, the control of diesel engines becomes a very difficult task involving five to 10 control variables that interact with each other and that are highly nonlinear. Until the present day, the control schemes integrated in the engine's controller are all based on static maps identified by steady‐state engine mapping. Afterward, these schemes are adjusted and calibrated in the vehicle using various control techniques in order to assure a better dynamic response of the engine under dynamic load. In this paper, we are interested in developing a mathematical optimization process that searches for the optimal control scheme under static and dynamic operating conditions. Firstly, we suggest modeling the engine and its emissions using mean value models which require limited experiments and are in good agreement with the experimental data. These models are then used in a dynamic optimization process based on the Broyden–Fletcher–Goldfarb–Shanno algorithm in order to find the optimal control scheme of the engine. The results show a reduction of the engine emissions without deteriorating its performance. Finally, we propose a practical control technique based on neural networks in order to apply these control schemes online to the engine. The results are promising. Copyright © 2007 John Wiley & Sons, Ltd.     

Optimal weaving for 2.5D interlocks

This paper deals with optimizing the representative volume element (RVE) of 2.5D interlock composites for enhanced damage resistance and elastic stiffness. The elastic moduli of the composite are determined as a volume average of the moduli of the matrix and fiber, while the overall resistance to failure is obtained through incremental use of the 3D Tsai-Wu failure criterion. The variables considered for the optimization problem are the volume fractions of the fibers, their proportions in each direction and the weaving step of the vertical reinforcement. The optimization is carried out using a sequential quadratic programming approach (SQP) and the results are validated against experimental data obtained for 2.5D interlocks with carbon reinforcements.     

Scaling of i DDT Test Methods for Random Logic Circuits

We present a scaling methodology to improve i_DDT fault coverage in random logic circuits. The study targets two i_DDT test methods: Double Threshold i_DDT and Delayed i_DDT. The effectiveness of the scaling methodology is assessed through physical test measurements, and studied relative to process variation and impact on circuit performance. The scaling is made possible using a clustering methodology that can significantly improve fault coverage. The results show that without clustering, the effectiveness of the i_DDT testing methods considered is greatly reduced as the circuit size increases. Editor: Z Li Ali Chehab received his Bachelor degree in EE from the American University of Beirut (AUB) in 1987, the Master’s degree in EE from Syracuse University, and the PhD degree in ECE from the University of North Carolina at Charlotte, in 2002. From 1989 to 1998, he was a lecturer in the ECE Department at AUB. He rejoined the ECE Department at AUB as an assistant professor in 2002. His research interests are VLSI design and test, mobile agents, and wireless security. Rafic Makki is currently serving as Dean of the College of Information Technology at UAE University. Rafic began his career with the University of North Carolina at Charlotte in 1984, serving the university for a period of 19 years. Rafic is the recipient of several awards including the 2005 IBM Faculty Research Award (first in the Middle-East), the 2002 First Citizen Research Scholar Medal, and the ALCOA Outstanding Graduate Faculty Award. Rafic received a PhD in Electrical Engineering in 1983 from Tennessee Tech University. His research interests include design for testability and defect-based testing.