Pressure injury is the most important issue facing paralysis patients and the elderly, especially in long-term care or nursing. A new interfacial pressure sensing system combined with a flexible textile-based pressure sensor array and a real-time readout system improved by the Kalman filter is proposed to monitor interfacial pressure progress in the cardiac operation. With the design of the Kalman filter and parameter optimization, noise immunity can be improved by approximately 72%. Additionally, cardiac operation patients were selected to test this developed system for the direct correlation between pressure injury and interfacial pressure for the first time. The pressure progress of the operation time was recorded and presented with the visible data by time- and 2-dimension-dependent characteristics. In the data for 47 cardiac operation patients, an extreme body mass index (BMI) and significantly increased pressure after 2 h are the top 2 factors associated with the occurrence of pressure injury. This methodology can be used to prevent high interfacial pressure in high-risk patients before and during operation. It can be suggested that this system, integrated with air mattresses, can improve the quality of care and reduce the burden of the workforce and medical cost, especially for pressure injury.

Effect of solidification cooling rate on Ag 3 Sn formation and its morphological appearance in Sn-Ag based lead-free solder was investigated. Depends on cooling rate, three types of Ag 3 Sn compound with different morphologies may form by solidification. They are particle-like, needle-like, and platelike respectively. Small particle-like Ag3Sn in large amount was occurred by rapid cooling, where plate liked Ag 3 Sn was formed by slow cooling condition. Extremely slow cooling such as furnace cooling results large plate-like or pillar-like Ag 3 Sn to form, particularly in solder matrix adjacent to the solder/Cu interface. The enrichment of Sn in Cu 6 Sn 5 IMC layer formation at interface causes Sn depletion at the adjacent area near the interface. As a result, Ag atoms were enriched relatively which favored formation and growth of primary Ag3Sn in liquid phase.

The relation between cooling rate and morphology of Ag 3 Sn IMCs was investigated in this study. The morphology of Ag 3 Sn intermetallic compounds of eutectic Sn-3.5Ag solder was investigated after solidification at different cooling rates. As the nucleation time of Ag 3 Sn depended on cooling rate, the morphology and size of Ag 3 Sn compounds were affected by cooling rate. The three types of Ag 3 Sn compound during different cooling rate solidification were found to be particle-like, needle-like, and plate-like in Sn-3.5Ag solder. The results show that as the cooling rate decreases, the morphology of Ag 3 Sn formed in Sn-3.5Ag solder transforms progressively from particle-like to plate-like.

The goal of this research is to evaluate the effects of La addition on the microstructure and microhardness of Sn-Ag based solders. Sn-3.5Ag-xLa ternary alloy solder were prepared by adding 0-1.0wt% La into a Sn-3.5Ag alloy. Copper substrates were then dipped into these solders and aged at 150°C for up to 625 hours. The microstructure and microhardness of the as solidified solder and the aged solder/copper couples were investigated.Experimental results show that Sn-3.5Ag-xLa solders are composed of~-Sn, Ag 3 Sn and LaSn3 phases, and their microstructure is refined with La addition. After isothermal aging, Ag 3 Sn and IMC layer can be effectively depressed by adding a small amount of La element, and the size and amount of LaSn3 compounds did not change perceptibly with storage time. The addition of La increased the microhardness of the Sn-Ag solder due to the refining effect of Ag 3 Sn particles in eutectic and increased formation of LaSn3 compound. After isothermal storage, the microhardness of solders was decreased with the increasing coarsening of Ag 3 Sn compounds as aging time was increased. However, coarsening of Ag 3 Sn compounds was retarded by La addition as revealed in this study. Therefore, La addition helped to improve the microhardness and thermal resistance of the solder joints.

The goal of this research is to evaluate the effects of La addition on the microstructure and microhardness of Sn-Ag based solders. Sn-3.5Ag-xLa ternary alloy solders were prepared by adding 0-1.0wt% La into a Sn-3.5Ag alloy. Copper substrates were then dipped into these solders and aged at 150°C for up to 625 hours. The microstructure and microhardness of the as solidified solder and the aged solder/copper couples were investigated. Experimental results show that Sn-3.5Ag-xLa solders are composed of β-Sn, Ag 3 Sn, and LaSn 3 phases, and that their microstructure is refined with La addition. After isothermal storage, the Ag 3 Sn and IMC layer can be effectively depressed by adding a small amount of La element, and the size and amount of LaSn 3 compounds does not change perceptibly with storage time. For as-cast solder, the addition of La increased the microhardness of the Sn-Ag solder due to the refining effect of Ag 3 Sn particles in the eutectic zone and increased formation of LaSn 3 compound. After isothermal storage, the microhardness of solders was decreased with the increasing coarsening of Ag 3 Sn compounds as aging time was increased. However, coarsening of Ag 3 Sn compounds was retarded by La addition. Therefore, La addition helped to improve the microhardness and thermal resistance of the solder joints.