Hierarchical VLSI Fault Tracing by Successive Circuit Extraction from CAD Layout Data in the CAD-Linked EB Test System

A hierarchical VLSI fault tracing method is proposed which isapplicable to the case where only CAD layout data is available in theCAD-linked electron beam test system. The CAD layout data is assumedto be hierarchically structured. The method uses the expansion of apreviously proposed integrated algorithm which combines atransistor-level fault tracing algorithm and a successive circuitextraction from a non-hierarchically or a flat structured CAD layoutdata. The method allows us to trace a fault hierarchically from thetop level cell to the lowest primitive cell and from the primitivecell to the transistor-level circuit in a consistent mannerindependent of circuit functions even when the cell data and thetransistor-level circuit data exist in a level as a mixture. Anapplication of the method to a hierarchically structured CMOS modellayout with about 600 transistors shows its validity.     

The gelatinization and retrogradation of cornstarch gels in the presence of citric acid

The effects of citric acid on the gelatinization and retrogradation for 20 wt% cornstarch gels were studied by differential scanning calorimetry (DSC) measurements, uniaxial compression tests and dynamic viscoelastic measurements. The pH value of cornstarch dispersion was adjusted to between 5.0 and 3.0 by adding citric acid. The pH of gels without citric acid (control) was 6.3. The cornstarch gels with pH value adjusted to 3.0 were brittle, while the values of Young’s modulus and dynamic viscoelasticity were higher than those of other samples. It is thought that hydrolysis of amylose and amylopectin chains by adding citric acid occurred and the length of elastically active chains decreased, also leading to the formation of new networks. It was found that when cornstarch gels with added citric acid were stored, they became brittle, but became hard to deform against small deformation. However, when cornstarch gels with or without citric acid were stored for longer time at 5 °C, the retrogradation ratio estimated by thermal analysis was not affected by the presence of citric acid.     

Quantitative evaluation of initial galvanic corrosion behavior of CNTs reinforced Mg–Al alloy

The macroscopic corrosion phenomenon of the CNTs reinforced Mg composites remarkably occurred in the moist environment, due to a large potential of the galvanic cells formed between α-Mg matrix and CNTs. Therefore, it is necessary to reduce the potential difference at their interfaces in order to obstruct the galvanic corrosion phenomenon. In this study, AZ61B alloy composites reinforced with CNTs (CNT/AZ61B) were fabricated by powder metallurgy method, and their potential differences between CNTs and the α-Mg matrix were reduced by concentration of Al atoms around CNTs via heat treatment. The potential distribution around CNTs was measured by using scanning Kelvin probe force microscopy (SKPFM). Heat treatment of CNT/AZ61B composites at 823 K for 10 h caused the obvious concentration of Al atoms around CNTs, and resulted in the remarkable decrease of the potential difference at the interface between the α-Mg matrix and CNTs. Additionally, the salt water immersion test results indicated that the corrosion rate of CNTs/AZ61B composite materials after heat treatment was obviously reduced to less than about 30% of the non-treated composite material. Thus, the changes of α-Mg matrix potential by concentrating Al atoms around CNTs was effective to improve initial galvanic corrosion resistance of CNTs reinforced Mg composites.     

Viscoelastic and fragmentation characters of model bolus from polysaccharide gels after instrumental mastication

Model bolus from polysaccharide gels was investigated by the stress-relaxation tests and particulate size analyses. Using two gelling agents, gellan gum and a composite of gellan/psyllium seed gums, gels with different physical properties (i.e., elastic gellan single gels and plastic composite gels) and gel hardness were prepared. Gels were masticated instrumentally in the presence or absence of artificial saliva to prepare model bolus. Data from the stress-relaxation tests analyzed by 5-element mechanical model showed that difference between two Maxwell-bodies in the elasticity for the composite gels was generally smaller than that for gellan single gels when compared at equivalent gel hardness and was less influenced by the addition level of saliva. For each gel sample, cumulative particulate size distribution of model bolus was reduced logarithmically with a normal curve regardless of the addition level of saliva. Mean particulate size of model bolus from the composite gels was generally larger than that for gellan single gels when compared at equivalent gel hardness and was less influenced by the addition level of saliva. Based on the particulate size distribution of model bolus, coefficients of skewness and kurtosis calculated for the composite gels tended to be larger than those for gellan single gels when compared at equivalent gel hardness. Results indicated higher structural homogeneity of model bolus from the composite gels, which is related to higher miscibility with saliva. Structural homogeneity should be the key for texture design of nursing-care foods, particularly for dysphagia.     

Effect of heating–cooling on rheological properties of tapioca starch paste with and without xanthan gum

The effect of xanthan gum (Xan) on pasting and gelatinization behavior of tapioca starch (TS) was investigated. Rheological measurements of TS/Xan mixtures with 5% w/w total polysaccharide concentration at different mixing ratios (10/0, 9.5/0.5, 9/1 and 8.5/1.5) were performed to understand the pasting and gelatinization behavior of TS with and without Xan on heating–cooling cycle using a Rapid Visco Analyzer (RVA) and conventional rheometers. Xan increased storage modulus (G′) and loss modulus (G″) of TS dispersions during gelatinization process. Pastes of TS/Xan tended to be more solid-like, i.e., G′ larger than G″, with increasing Xan. The G′ of TS/Xan paste increased when kept at 10 °C indicating the network formation. Pasting temperatures, peak viscosity, final viscosity and breakdown values of TS increased with increasing Xan content but the opposite result was observed in setback value from RVA measurement. Temperature dependence of steady shear viscosity became less pronounced with increasing Xan content on both cooling and reheating indicating that Xan made the mixture more thermally stable. All the results suggest that the sample preparation and measuring conditions influence the rheological properties of TS/Xan mixtures, which should be taken into account in food application.     

Photoinduced phenomena in group VIb glasses

Two aspects of photoinduced phenomena in oxide and chalcogenide glasses have been studied. One is a comparison of irreversible, reversible, and transitory changes in As₂S₃, which gives insights into universal features of the photoinduced phenomenon. The other is composition dependence of structures and photodarkening in GeO₂–GeS₂ glasses. The dependence suggests that percolating GeS₂ structures are required for the photodarkening.