-Recently, in the field of renewable energy such as solar cells including the semiconductor and display industries, thin film deposition process is being diversified. Furthermore, to deal with trend of making high-quality and fast, the high-capacity and output plasma power supply which can control high density plasma is required. The biggest problem is arc discharge caused by using high voltage power supply. Thus, the key function of plasma power supply is to prevent arc discharge and there is a need to maintain the possible minimum arc energy. In DC sputtering power supply, on a periodic basis (-)voltage powering up is able to significantly reduce arcing, as well as arc discharge prevention, and maintaining uniform charge density. This conventional method for powering up (-)voltage requires heavy mutual inductance of the transformer to avoid distortion problem of the output voltage. This study is about energy recovery circuit for arc discharge prevention in sputtering plasma power supply. By using energy recovery circuit, it is possible to reduce the mutual inductance and size of the transformer dramatically, prevent distortion of the output voltage and has a stable output waveform. This work was proved through simulation and experimental study.

The purpose of this study was to identify changes in the center of pressure during stair ascending in subjects with chronic ankle instability while different angles of foot are applied. The subjects of this study were 20 male and female adults with chronic ankle instability were selected from among the employees of D Hospital in Daegu Metropolitan City. The criteria for selection of subjects with chronic ankle instability were those who felt wobbling in the ankle joint and scored not higher than 24 points in a test using the Cumberland Ankle Instability Tool (CAIT). The subjects carried out stair ascending in neutral, toe-in and toe-out postures, respectively, and changes in the center of pressure (COP) were compared and analyzed. The results of this study, no statistically significant difference appeared in the comparison between the toe-in posture and neutral posture or between the neutral posture and the toe-out posture but medial/lateral movements of the center of pressure showed significant differences between the toe-in and toe-out postures. In addition, the total travel range and the moving range of the center of pressure, the average velocity, and the anterior/posterior movements of the center of pressure showed no statistically significant difference among all three postures. As a result, it could be seen that when adults with chronic ankle instability climb the stairs, the toe-in posture reduce the medial/lateral movements of the center of pressure thereby increasing the stability of the ankle and effectively preventing re-injuries.

In subjects with functional ankle instability, lumbopelvic instability causes instability of the hip and lower extremities. The purpose of this study is to determine whether an ankle exercise program with hip strengthening exercise and lumbopelvic stabilization exercise affects spine and ankle stability through muscle activity in adults with functional ankle instability. Thirty adults with functional ankle instability were randomly assigned to a hip joint strengthening exercise group and a lumbopelvic stabilization exercise group. The subjects participated in the designated program three times a week for 40 minutes a day. In the hip joint strengthening exercise group, a general hip joint strengthening exercise was used, and in the lumbopelvic stabilization exercise group, a lumbopelvic stabilization exercise using a sling was added. The intervention lasted 4 weeks, and both groups were instructed to refrain from other exercise during the 4-week intervention period. The muscle activity of the tibialis anterior, gluteus maximus, external oblique and contralateral latissimus dorsi was measured. Data were collected from the 30 patients. The results showed that the muscle activity of the tibialis anterior, gluteus maximus, lateral oblique muscle, and contralateral latissimus dorsi was significantly increased in both groups. This suggests that the existing hip joint strengthening exercise and lumbopelvic stabilization exercise are effective approaches which not only help reduce hip joint pain and improve function, but also reduce functional ankle instability. Therefore, if an appropriate exercise program is provided for subjects with functional ankle instability, it is expected that it will help improve pain and function by reducing ankle instability and the frequency of re-injury.