Effect of bismuth on the growth kinetics of intermetallic compounds in Sn-3.5Ag solder joints: A growth kinetic model

The effect on the growth kinetics of the intermetallic compounds (IMCs) in solder/Cu joints, caused by adding Bi to eutectic Sn-3.5Ag solder alloy, was examined at the aging temperatures of 150°C and 180°C. The Cu₆Sn₅ layer growth was significantly enhanced, but the Cu₃Sn layer growth was slightly retarded by the addition of Bi, resulting in significant growth enhancement of the total (Cu₆Sn₅+Cu₃Sn) IMC layer with increasing Bi addition. The IMC layer growth in the Bi-containing solder joints was accompanied by the accumulation of Bi ahead of the Cu₆Sn₅ layer that resulted in the formation of a liquid layer at the Cu₆Sn₅/solder interface. A kinetic model was developed for the planar growth of the Cu₆Sn₅ and Cu₃Sn layers in the solder joints, accounting for the existence of interfacial reaction barriers. Predictions from the kinetic model showed that the experimental results could be well explained by the hypothesis that the formation of a Bi-rich liquid layer at the Cu₆Sn₅/solder interface reduces the interfacial reaction barrier at the interface.     

The fabrication of functional biosurface composed of iron storage protein, ferritin

A functional biosurface applicable to a biomemory device was fabricated using ferritin, which is one of the globular protein complexes consisting of 24 protein subunits, which can be classified as metalloproteins. For the fabrication of uniform ferritin layer, 11-MUA(11-mercaptoundecanoic acid) was used as a linker material. The formation of the ferritin layer was confirmed by surface plasmon resonance (SPR) spectroscopy, and the morphology of the immobilized ferritin was analyzed by scanning tunneling microscopy (STM). The electrochemical redox property investigation was accomplished by the cyclic voltammetry (CV) technique. These results of adsorbed ferritin on the modified electrode can be used for the fabrication of bioelectronics.     

Water removal characteristics of proton exchange membrane fuel cells using a dry gas purging method

Water removal from proton exchange membrane fuel cells (PEMFC) is of great importance to improve start-up ability and mitigate cell degradation when the fuel cell operates at subfreezing temperatures. In this study, we report water removal characteristics under various shut down conditions including a dry gas-purging step. In order to estimate the dehydration level of the electrolyte membrane, the high frequency resistance of the fuel cell stack was observed. Also, a novel method for measuring the amount of residual water in the fuel cell was developed to determine the amount of water removal. The method used the phase change of liquid water and was successfully applied to examine the water removal characteristics. Based on these works, the effects of several parameters such as purging time, flow rate of purging gas, operation current, and stack temperature on the amount of residual water were investigated.     

Face recognition using face-ARG matching

In this paper, we propose a novel line feature-based face recognition algorithm. A face is represented by the face-ARG model, where all the geometric quantities and the structural information are encoded in an attributed relational graph (ARG) structure, then the partial ARG matching is done for matching face-ARG's. Experimental results demonstrate that the proposed algorithm is quite robust to various facial expression changes, varying illumination conditions and occlusion, even when a single sample per person is given.     

Biomemory device composed of mutant azurin thin films modified by site-directed mutagenesis

A bioelectronic device composed of self-assembled mutant azurin thin films with memory function has been developed for molecular electronics. Azurin was recombined with a cysteine residue to enhance the stability of self-assembled protein on gold surface. The thin films of protein on gold substrate were investigated by surface plasmon resonance spectroscopy, scanning tunneling microscopy and Raman spectroscopy, respectively. The memory characteristics, including the “read”, “write” and “erase” functions of self-assembled azurin layer, were obtained with three distinct electrical states of azurin layers by cyclic voltammetry. These results show the proposed biomemory device as a step towards the protein based nanobiochip.     

Physiological Assessment and Path Coefficient Analysis to Improve Evaluation of Alfalfa Autotoxicity

Reseeding of alfalfa is affected until autotoxic chemicals break down or are dispersed, often requiring a year or more. Bioassays of seed germination and early seedling growth, on agar medium in petri dishes, were conducted to evaluate autotoxic responses of 20 alfalfa germplasms to water-soluble extracts of alfalfa leaf tissue. Root length, 120 hr after placing imbibed seed on agar, was more sensitive to the autotoxin(s) than was hypocotyl length, germination speed, and final germination percentage. Path coefficient analyses showed variation in root length had 7–17 times more effect than variation in hypocotyl length in determining autotoxic effects on total seedling length. Although variations in seed size and germination rate were negatively associated (P < 0.05) with final root length, the autotoxin had little effect on these factors relative to that on root length. Germplasms in the control differed (P < 0.05) in root length, requiring tolerance to be evaluated as percent of control. Germplasms, as percent of control, differed significantly (P<0.05) at extract concentrations of 1.0 and 4.0 g l^–1, but the range and LSD were more favorable for selection at 1.0 g l^–1. Root length is appropriate for genetic assessments of tolerance to the autotoxin when expressed as percent of control.     

Developing platform specific model for MPSoC architecture from UML-based embedded software models

In this paper, we describe a technique to design UML-based software models for MPSoC architecture, which focuses on the development of the platform specific model of embedded software. To develop the platform specific model, we define a process for the design of UML-based software model and suggest an algorithm with precise actions to map the model to MPSoC architecture. In order to support our design process, we implemented our approach in an integrated tool. Using the tool, we applied our design technique to a target system. We believe that our technique provides several benefits such as improving parallelism of tasks and fast-and-valid mapping of software models to hardware architecture.     

Measuring behavioral dependency for improving change-proneness prediction in UML-based design models

Several studies have explored the relationship between the metrics of the object-oriented software and the change-proneness of the classes. This knowledge can be used to help decision-making among design alternatives or assess software quality such as maintainability. Despite the increasing use of complex inheritance relationships and polymorphism in object-oriented software, there has been less emphasis on developing metrics that capture the aspect of dynamic behavior. Considering dynamic behavior metrics in conjunction with existing metrics may go a long way toward obtaining more accurate predictions of change-proneness. To address this need, we provide the behavioral dependency measure using structural and behavioral information taken from UML 2.0 design models. Model-based change-proneness prediction helps to make high-quality software by exploiting design models from the earlier phase of the software development process. The behavioral dependency measure has been evaluated on a multi-version medium size open-source project called JFlex. The results obtained show that the proposed measure is a useful indicator and can be complementary to existing object-oriented metrics for improving the accuracy of change-proneness prediction when the system contains high degree of inheritance relationships and polymorphism.     

Multiscale Representation and Compression of 3-D Point Data

A compact representation scheme is presented for 3-D point data. To describe underlying surface from raw point samples, we dyadically divide a 3-D domain enclosing whole points. Then, local points in each cube are approximated by a plane patch, yielding a multiscale representation of 3-D surface. To reduce the redundancy between different scale models, the geometry innovation is evaluated between different scale planes, which reveals the Euclidian distance between planes. Finally, the geometry innovation coefficients are compressed by a zerotree-based encoder. Based on the multiscale plane representation of 3-D geometry and the efficient plane decomposition method, the proposed scheme provides a desirable framework for 3-D point geometry processing.     

Nanoscaled redox active protein adsorption on Au-dot arrays: An electrochemical scanning probe microscopic investigation for application in nano-biodevices

Highly dense and uniform protein dot arrays on Au-nanodots using size controllable method were fabricated on indium tin oxide (ITO) substrate in order to develop an electrochemical nanobiochip. Cysteine modified azurin was directly immobilized on the fabricated Au-nanodots without any linker materials. Atomic force microscopy was used for characterizing Au-dots formed on ITO substrate. Electrochemical scanning tunneling microscopy (ECSTM) revealed the monolayer formation with an in situ cyclic voltammetry to observe redox behaviour of both bare Au-dots and protein immobilized Au-dots. I–V characteristics were obtained on both bare Au-dots and protein immobilized Au-dots structured on ITO conductive electrodes.