Now, the development of lead-free solder alloys and soldering technology using them is pushed forward by global scale. Among them, the examination for the Sn-Ag-Cu solder is pushed forward mainly for the reason of being superior in joint reliability although the melting point is higher. And products using this solder are already on the market partly. However, in flow soldering with Sn-Ag-Cu solder, peculiar defects called shrinkage cavity, fillet-lifting and land-lifting occur at solder joints. And these defects become one of a problem toward full-scale practical use. In this study, we investigated the influence that shrinkage cavities occurred on the solder joint surface in flow soldering with Sn-3.5 mass%Ag-0.75 mass%Cu lead-free solder on reliability. Furthermore, we added examination about prevention of shrinkage cavity. As a result, the shrinkage cavity understood not to become a fatal defect and not to largely decrease reliability of solder joints. We understood also, that shrinkage cavities are prevented by water cooling just after soldering or increasing the silver content.

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L-アラビノースは，天然由来の五炭糖の一つで，とうもろこし，甜菜などの植物の細胞壁のヘミセルロースの構成成分として豊富に存在する。食品中には，遊離の状態で，味噌，醤油やウイスキーなどの発酵食品に少量ではあるが，含まれている。L-アラビノースは，糖質でありながら，小腸においてスクラーゼを阻害することで，砂糖摂取に伴う血糖値の上昇を抑制することが知られている。動物やヒトでの試験において，L-アラビノースを砂糖に対して2-3％添加することで，砂糖摂取後の血糖値上昇を約50％抑制することが報告されている。本稿では，L-アラビノースの生理機能について解説する。また，食品用途への応用として，食物繊維との配合による相乗効果について紹介する。

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L-Arabinose is a natural, poorly absorbed pentose that selectively inhibits intestinal sucrase activity. Rats were fed for 4 weeks on a 20% sucrose diet containing 1% L-arabinose. Experiment 1 was carried out to investigate the effects of L-arabinose feeding on the intestinal microflora and weights of the cecum, cecal contents and fat pad. In experiment 1, the cecal contents in 5% glucose containing 3% skim milk were frozen at -80°C until needed for incubation, while the cecal contents in experiment 2 were incubated immediately after dissection.
The body weights of the rats fed on the 1% L-arabinose diet were not significantly different from those fed on the control diet. The weight of the fat pad tended to be less in the L-arabinose group than in the control group, while the weight of the cecum and amount of ammonia in the cecal contents were significantly higher with L-arabinose ingestion. The amount of total organic acids tended to be highest in the cecal contents of the L-arabinose group.
Bifidobacteria were observed in the L-arabinose group in experiments 1 and 2, but not in the control group. The viable count of bifidobacteria was not influenced by preserving the cecal contents at -80°C. The results suggest that L-arabinose feeding influenced the intestinal microflora and induced the production of bifidobacteria.

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Correlation between composition and shrinkage cavity of Sn-Ag-Bi-Cu lead-free solder alloys was investigated. Incidence of surface cracks on solder fillets, caused by shrinkage cavity, was significantly influenced by Ag content of solder alloys (1.0-2.5wt%) ; for solder fillets with less than 2.0wt% of Ag content, surface cracks decreased in accordance with a reduction in Ag content. On the other hand, incidence of surface cracks was independent of Bi content of solder alloys (0-4.0wt%) . Compositional mapping analysis with EDX revealed that less Ag₃Sn phases were formed for solder fillets with less Ag content, suggesting that the formation of the Ag₃Sn/Sn eutectic network band triggers the formation of surface cracks, i.e., shrinkage cavity. Wettability of solder alloys with various Ag contents was also investigated. It was clarified that a decrease in Ag content leaded to degradation of solder wettability, indicating an increase in liquidus temperature of solder.

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L-アラビノースは植物細胞壁の構成糖の1つであるペントースで, L体として多く存在する。植物細胞壁の1つコーンファイバーをシュウ酸で限定分解することで, L-アラビノースを多く含む糖液の調製を行い, 精製, 工業的クロマト分離, 晶析工程等を経て高純度(99%以上)のL-アラビノースを生産する技術開発に成功した。L-アラビノースそれ自体は腸管から3.4%しか吸収されないが, 小腸スクラーゼを阻害することから,ショ糖由来の血糖上昇を抑制する。その阻害はα-グルコシダーゼの中でスクラーゼに対して特異的で, 阻害機構は不拮抗型であった。有効な添加量はショ糖に対し3～4%で, 血糖上昇, インスリン分泌を有意に抑制し, 60分間の血糖曲線下面積を40%低減した。効果の持続性では, in vitroではスクラーゼ付近で4時間以上滞留すると共に, ヒト試験では2時間後に摂取した糖負荷食(市販の羊羹)の血糖上昇を有意に抑制した。その安全性は, 動物やヒトを用いた試験で確認された。ショ糖を含む食品だけでなく, ショ糖を含まなくともショ糖を含む食品と一緒に摂る食品への添加用素材としてL-アラビノースは有用である。

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