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本報では，車載電装部品において疲労信頼性が最も重要視されるチップ部品の実装プロセスが及ぼすはんだ接合部の形状への影響を調べるため，実験結果との一致性の高い鉛フリーはんだのリフロープロセスのシミュレーション手法を提案する。その解析手法を用いて，実装プロセスの各要因によるはんだ接合部の形状への影響を評価し，実験的アプローチでは発見が困難である各要因間の交互作用の存在を検証できることを示した。そして，実装プロセスの各要因のばらつきを考慮した形状予測のシミュレーションの後に疲労寿命解析をすると，各要因のばらつきがどのような信頼性問題を引き起こすか評価できることを示唆した。

岡山県南西部に位置する地方都市である、倉敷市在往、成人の栄養および生活活動の実態調査を行った。対象は年齢20才代から60才代の男子227名女子253名であった。栄養摂取量は簡易半定量食物摂取頻度調査法により調査を行った。各栄養素と食品群別摂取量は第5次改定の日本人の栄養所要量とそれに基づく望ましい食品群別摂取量と比較した。40才代以上の年代の栄養素摂取量と運動習慣は20才代や30才代のそれらに比べ良い結果が得られた。特に30才代の男子で運動習慣の低さや全般的な栄養素の不足、食物繊維やカルシウムの摂取不足が認められた。これらの結果をみると、20才代や30才代の男子は将来の生活習慣病のリスク集団の可能性があり、この年代に焦点を当てた対策が必要と思われる。

In this paper, authors proposed an original sensor which can measure thermal fatigue life of electronic equipment. The measurement principle of the sensor is that the joint was damaged by the stress due to a mismatch of thermal expansion between two materials. Finally, the joint was ruptured by the repeated stress. The priority subject was the feasibility of measurement accuracy of the sensor. Generally, a high level control of failure in joint is very difficult. To solve this problem, authors conceived the original design of the sensor. Then, the availability study of the original sensor for fracture control in joint was carried out using the crack propagation analysis. In the result, a high level control method for failure in joint of the sensor was achieved.

This paper proposes the high reliable design method for lead-free solder joint on metal substrate on chip component. First, the crack propagation analysis method for estimating rupture life of solder joint was constructed. And then, the effect of material properties of insulating layer on metal substrate and solder joint shape for rupture life of solder joint was evaluated using crack propagation analysis. As the result, the relation between young’s modulus of insulating layer and rupture life was indicated quantitatively. Also, the relation of filet length for rupture life of solder joint was evaluated. Secondary, evaluation method of heat dissipation for metal substrate was proposed. Because thermal conductivity of insulating layer affects temperature rise of heating device. And, the relation between thermal conductivity of insulating layer and temperature rise of heating device was indicated.Copyright © 2011 by ASME

This paper presents the high reliability design method for lead-free solder joints on chip components, and that is able to evaluate effect of soldering process for solder joint shape. Coupled analysis of structure analysis and flow analysis was proposed for replication of solder wetting and behavior of electric components at the same time. The analysis methods enable to evaluate complex mechanism of solder joint shape formation caused by soldering process fluctuation including the interaction between factors. Then, the estimated model of solder joint was evaluated the fatigue life using crack propagation analysis based on finite element method. The crack propagation method was provided the improvement for the complex behavior elucidation of crack propagation mode. Also, this paper indicated the importance of the analysis method for reliability design of solder joint in products required small-size and high reliability like automotive electronic components.

The miniaturization and high reliability for automotive electronic components has been strongly requested. Generally, electronic component and printed wiring board are connected using solder joint. The reliability of solder joint has widely dispersion. For the dispersion reduction of solder joint reliability, not only design factors but manufacturing factors should be optimized. The evaluation of manufacturing factors for solder joint reliability was very difficult by experimental evaluation alone. Therefore, the reflow process simulation was established. The simulation was reenacted soldering process on chip component, which was the most severe reliability in automotive electronic components. The novelty of simulation was the coupled analysis of flow and rigid for simulating self-alignment of chip component. In this simulation, contact angle and surface tension was very important factor. So, these characteristics were measured based on Spread test and Wetting balance tests using the specimens. In the result, the solder joint shape of analysis was agree with the one of specimens using the measured contact angle and surface tension. Next, the effect of manufacturing process dispersion for solder joint shape was evaluated. The factors were mount offset and length unbalance of electrodes on chip component. As a result, the mount offset was not affected solder joint shape of chip component until a certain level. Also, the unbalance of electrode of chip component was not almost affected for solder joint shape of chip component because a part was moved to the center of part by surface tension of solder joint. Finally, the relation between the estimated solder joint shape and fatigue life of solder joints is evaluated using crack propagation analysis based on Manson-Coffin’s law and Miner’s rule. When the value of mount offset was large, the crack propagation mode was changed and the fatigue life of solder joint was decreased. As mentioned above, it was able to evaluate the relation between manufacturing factors and solder joint reliability. Accordingly, this simulation was very useful for consideration on the miniaturization, high reliability and appropriate margin for design of electronic components.

This paper describes transient cooling technology for electronic equipment using Phase Change Materials (PCMs) and a heat sink with pin fins. We designed an electronic module including paraffin as the PCM and measured its transient temperature rise. The effects of the diameter of pin fins and heat dissipation values were investigated as design parameters. The results show that the temperature rise values were controlled by the thermal absorption effect due to the latent heat of the PCM. It is also confirmed that the proposed thermal network method with an equivalent specific heat model has strong potential for use in the analysis of electronic modules using PCMs.Copyright © 2009 by ASME

An outbreak of Yersinia pseudotuberculosis in Kurashiki, Japan is described. This is the first conclusive report of a community outbreak of this microorganism. A total of 535 pupils, five teachers, and one food attendant contracted the organism. Causative organisms were detected in 19 out of 30 patients. All isolated strains belonged to serotype VA. Out of 653 sera of the pupils, 488 showed elevated agglutinin titers ranging from 1: 80 to 1: 1,280 or more within a period of 3 months.