In this study, dissolution and melting phenomenon of the Al₂Cu was studied for the high-strength Al-Si-Cu aluminum alloy in automobile component. The Solution heat treatment was performed at 480℃ and 510℃ for 4hours. Microstructure analysis of the specimen was performed using the optical micrograph and scanning electron microscope for qualitative and quantitative analysis of various phases, the chemical composition of secondary phases was achieved by energy dispersive spectroscopy (EDS) and electron probe micro analysis (EPMA). As a result of the electron probe micro analysis, a plate like Al₂Cu phase was observed, and eutectic Si phase was observed of a coarsen plate shape. At a temperature of 510, necking phenomenon occurs in a specific part of plate like Al₂Cu, and it is segmented and dissolved in the Al matrix. When the temperature of the alloy exceeds the melting point of Al₂Cu, incipient melting occurs at the grain boundary of undissolved Cu particles

The metallic implant materials are widely used in biomedical industries due to their specific mechanical strenth, corrosion registance, and superior biocompatability. These metallic materials, however, suffer from the stress-shielding effect and the generation of artifacts in the magnetic resonance imaging exam. In the present study, we develope a Zr-based alloys for the biomedical implant materials with low elastic modulus and low magnetic susceptibility. The Zr-7Si-xSn alloys were fabricated by an arc melting process. The elastic modulus was 24~31 GPa of the zirconium-based alloy. The average magnetic susceptibility value of the Zr-7Si-xSn alloy was 1.25 × 10^-8cm³g^-1. The average I_corr value of the Zr-7Si-xSn alloy was 0.2 ㎂/cm². The Sn added zirconium alloy, Zr-7Si-xSn, is very interested and attractive as a biomaterial that reduces the stress-shielding effect caused by the difference of elastic modulus between human bone and metallic implant.

This paper was designed to prevent intervertebral disc escape and treatment. we produced downsized lumbar traction bed at home and automated system depending on weight and muscle mass by using 3D print and Arduino to confirm the possibility of prototyping. Hence, we checked muscle mass 10 males in their 20s with different exercise conditions, and it shows that average muscle mass of group who exercised was 56.63kg, and non-exercise group was 50.8 kg. this is shows lumbar repetitive exercise can show the traction therapy effect can be seen traction therapy effect. In addition, we installed wooden doll substitute people with spring and test changing of length. Traction bed has the steps ranging from 1 to 4, in which the motor with torque and rpm, ranging from 4.7 to 5.5 kgf and from 4.5 to 5.3 rpm, respectively. The motor controlled with the voltage of Arduino was operated for the length of the spine to be stretched to 4-5 mm. As increasing the weight of the wooden doll by 10g, it was confirmed that the spring increased by 4-5 mm from the first step to the fourth step.

Microbubble technology has been widely applied in various industrial fields. Recently, research on many types of microbubble application technology has been conducted experimentally, but there is a limit in deriving the optimal design and operating conditions. Therefore, if the computational fluid dynamics (CFD) analysis of multiphase flow is used to supplement these experimental studies, it is expected that the time and cost required for prototype production and evaluation tests will be minimized and optimal results will be derived. However, few studies have been conducted on multiphase flow CFD analysis to interpret fluid flow in microbubble generators using swirl flow. In this study, CFD simulation of multiphase flow was performed to analyze the air-water mixing process and fluid flow characteristics in a microbubble generator with a dual-chamber structure. Based on the simulation results, it was confirmed that a negative pressure was formed on the central axis of rotation due to the strong swirling flow. And it could be seen that the air inside the suction tube was introduced into the inner chamber of the microbubble generator. In addition, as the high-speed mixed fluid collided with external water sucked by the negative pressure near the outlet, a large amount of microbubbles was ejected due to the shear force between the two flows flowing in opposite directions.