Interconnection reliability and interfacial structure between Au alloy bump and Al pad using ultrasonic bonding*

Flip chip technology with Au bumps on a substrace has been widely applied to electronic equipment such as smart phones. The purposes of this study are to examine the effect of Al pad thickness on the bondability of flip chip using ultrasonic bonding and to clarify interfacial structures between Au alloy bumps and Al pads by ultrasonic bonding compared before and after a thermal cycle test. Suitable Al thickness for excellent initial Au/Al bonding without chip cracking are 0.8 μm because a thin Al layer could not reduce stress to a chip under an Al pad during the ultrasonic bonding process. Intermetallic compounds between the Au alloy bump and chip after reflows consisted of five Au-Al layers, and a pure Al layer remained. On the other hand, after the temperature cycle test at 218/423 K, intermetallic compounds between the Au alloy bump and chip were changed into two kinds of Au-Al layers, so a pure Al layer did not exist. In addition, if thick intermetallic compound layers existed around the bonding region, bondability deteriorated easily by thermal stress due to a thermal cycle test, therefore the open failure rate was rising when the Au thickness was 1.2 μm.     

Degradation of cyanuric acid in soil by Pseudomonas sp. NRRL B-12227 using bioremediation with self-immobilization system

The rates of degradation of cyanuric acid, a key intermediate in a metabolic pathway of s-triazine herbicides, were measured for Pseudomonas sp. NRRL B-12227. The rate of degradation was affected by the rate of cyanuric acid transport through cell membranes and the activity of cyanuric acid amidohydrolase inside the cells. At low concentrations of cyanuric acid, the acclimation of cells to cyanuric acid and/or added nutrients effectively enhanced the degradation rate. The strain was also applied to bioremediation using a Bioremediation with Self-Immobilization System (BSIS), in which Pseudomonas sp. NRRL B-12227 cells were co-immobilized with Bacillus subtilis, the latter of which secretes a viscous polymer, in a shallow layer of soil packed in a column. More than 70% of the Pseudomonas sp. NRRL B-12227 cells were co-immobilized with the B. subtilis in a 7.5 cm layer of the packed soil by self-aggregation. More than 60% of the 1 mM cyanuric acid supplied to the packed soil was degraded in this layer during a 72 h period.     

Investigation of the Aroma Profile of Green Tea Leaves Using Organic Synthesis and Conventional Analytical Techniques

Although many aroma components have been identified in green tea leaves, the aroma compounds contributing to green tea＇s characteristic odor have not yet been reported. The authors recently reported that aroma components with a matcha-like odor are present in both green tea and black tea prepared from the Sayamakaori tea cuttivar. This matcha-like odor is similar to the odor of commercial available matcha （high-quality powdered green tea）, and is a specific odor feature of green tea leaves. At present, the green-tea odor is thought to arise from the combination of a large number of constituents. Recent reports indicate that a complex interaction between olfactory receptors and odorants is important for the evaluation of the odors. Taking into consideration these findings, the authors investigated the aroma profile of green tea, focusing on the characteristic molecular structures of the constituents that give matcha-like odor. Using a combination of organic synthesis and gas chromatography-mass spectrometry plus gas chromatography-olfactometry, the authors identified aroma components with matcha-like odors in five other tea cultivars. This investigation also revealed that several compounds with a formyl group were important constituents of the aroma of green tea leaves, although the odor of each constituent was not individually similar to the tea＇s overall aroma. The authors found for the first time a group of key components that have the matcha-like odor.     

Purification and characterization of a strong fibrinolytic enzyme (nattokinase) in the vegetable cheese natto, a popular soybean fermented food in Japan

A strong fibrinolytic enzyme (nattokinase) was purified from the vegetable cheese natto. Nattokinase was extracted from natto with saline and isolated by sequential use of hydrophobic chromatography on Butyl-Toyopearl, ion-exchange chromatography on CM-Toyopearl, and gel-filtration on Sephadex G-50. The isolated protein gave a single sharp band on SDS-PAGE either before or after reduction. The sequence, as determined by automated Edman degradation of the uncleaved molecule and its enzymatically derived peptide, consisted of a total 275 amino acid residues (M.W = 27,728) and exhibited a high homology with the subtilisins. The purified nattokinase digested not only fibrin but also several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was Suc-Ala-Ala-Pro-Phe-pNA for subtilisin. PMSF inhibited both the fibrinolytic activity and the amidolytic activity. The results indicate that nattokinase is a subtilisin-like serine protease.     

How do tufted capuchin monkeys (Cebus apella) understand causality involved in tool use?

Four tufted capuchin monkeys (Cebus apella) were trained to choose from 2 hook-like tools, 1 of which successfully led to collecting food, whereas the other did not because of inappropriate spatial arrangement of the tool and the food. In Experiment 1, all of the monkeys successfully learned the basic task. The monkeys performed successfully with tools of novel colors and shapes in Experiments 2-5. These results demonstrate that the monkeys used the spatial arrangement of the tool and the food as a cue. However, they failed when there were obstacles (Experiment 6) or traps (Experiment 7) on the path along which she monkeys dragged tools. These results may suggest that capuchin monkeys understand the spatial relationship between 2 items, namely, food and. the tool, but do not understand the spatial relationship among 3 items, namely, food, tool, and the environmental condition. The possible role of stimulus generalization is also considered. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of Spray‐Drying Parameters on In Vitro Functional Properties of Camu‐Camu (Myrciaria dubia Mc. Vaugh): A Typical Amazonian Fruit

Camu‐camu (Myrciaria dubia) fruit is a rich source of bioactive compounds but its shelf life is rather short. Therefore, this study was aimed to evaluate the effect of inlet air temperature (T) and concentration (C) of maltodextrin and arabic gum on the spray‐drying process of commercial camu‐camu pulps (São Paulo and Manaus). Moisture, solubility, total phenolics (TP), ascorbic acid (AA), and proanthocyanidins (PAC) contents, and in vitro antioxidant capacity of the powders (FRAP, DPPH, Folin–Ciocalteu's reducing capacity were measured). Arabic gum resulted in better yields (22% to 30%), powder solubility (84% to 90%), and lower losses of analyzed compounds than the powders manufactured with maltodextrin. Overall, inlet air temperature had a lower impact on the responses studied than the concentration of carrier agents. Polynomial equations were generated for AA (R² = 0.993), TP (R² = 0.735), PAC (R² = 0.946), and for the antioxidant capacity assays (0.867 ≤ R² ≤ 0.963). In addition, principal component analysis showed that the lowest concentration of carrier agents (6%) in spray drying resulted in the lowest losses of bioactive compounds and, consequently, the highest antioxidant capacity.     

μ-synthesis of an electromagnetic suspension system

This paper deals with μ-synthesis of an electromagnetic suspension system. First, an issue of modeling a real physical electromagnetic suspension system is discussed. We derive a nominal model as well as a set of models in which the real system is assumed to reside. Different model structures and possible model parameter values are fully employed to determine unstructured additive plant perturbations, which directly yield uncertainty frequency weighting function. Second, based on the set of plant models, we setup robust performance control objectives. Third, we make use of the D-K iteration approach for the controller design. Finally, implementing the controller with a digital signal processor, experiments are carried out. With these experimental results, we show robust performance of the designed control system     

Effectiveness of spatial representation in the formation of network communities: experimental study on community organizer

In this paper, we present and discuss Community Organizer, a system designed to support network communities. The main characteristic of Community Organizer is the use of spatial representations for the relationships among community members including the communications exchanged among these members. These spatial representations reflect the degree of closeness of interests and concerns among the members, and are intended to provide users with clues on how to form network communities. In order to investigate the effectiveness of the proposed spatial representations, we conducted experiments with two different versions of the software. One version offered meaningful spatial representations while the other version did not. The subjects who used the former software version felt a greater sense of ‘community’, enjoyed using the software more, and actively used it longer than the subjects using the latter software version (control condition). These results indicated that the proposed spatial representations are effective in supporting network community formation.     

Preparation of High-Performance Co3O4 Catalyst for Hydrocarbon Combustion from Co-Containing Hydrogarnet

Supported Co₃O₄ catalysts were prepared via the calcination of Co-containing hydrogarnet, (Ca_3-x Co _x )Al₂(SiO₄)_{3- y} (OH)_4y , at 400 °C. Such precursors with various extents of substitution were synthesized from the hydrothermal reaction of a stoichiometric mixture of calcium oxide, amorphous silica, alumina sol, and cobalt hydroxide at 200 °C. It was found that the catalyst consisted of Co₃O₄, CaO, and mayenite and exhibited a high activity for the combustion of propylene, benzene, and toluene at temperatures below 300 °C.     

Synthesis of terpene alcohols from isoprene oligomers

Various terpene alcohols were prepared from isoprene oligomers via two steps: epoxidation with peracetic acid and isomerisation with aluminium triisopropoxide. For example, 2-methylene-6-methyl-7-octene-1-o1 was prepared from 2,6-dimethyl-1,7-octadiene. From 2,6-dimethyl-2,7-octadiene, 3,3,6-trimethyl-1,5-heptadiene, 2,7-dimethyl-2,6-octadiene, 2,6-dimethyl-1,3,6-octatriene, 1-methyl-4-isopropenyl-1-cyclohexene, and 1,5-dimethyl-1,5-cyclooctadiene, the corresponding alcohols were obtained, respectively.