• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.538-545
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• 2019

The purpose of this study was to analyze the change of body temperature and pain by application of Gaussian magnetic for the elderly delayed muscle pain. For the purpose, we selected 15 elderly women(age;$69.47{\pm}1.60$) and conducted repeated experiments. The Gaussian magnetic field area was divided into three areas (1000G, 1500G, 2000G). The applying arbitrarily manufactured magnetic field wristbands changes of body heat and pain before and after wearing Gaussian magnetic were measured and collected data were analyzed using SPSS 19.0. To examine the pre-and post-treatment differences by treatment areas, we conducted paired t-test. Group differences and interaction effects were analyzed using two-way ANOVA and Duncan post hoc tests. The significance level was set to ${\alpha}=.05$. The results are as follows. The change of body heat by the Gaussian magnetic field area showed significant differences in all three groups(P<.05). There were also significant differences in the results of group interactions and in the delayed muscle pain scale between groups(P<.05). The area with the largest difference appeared in the area of 1500G field. The 1000G-1500G Gauss field is considered to be the most ideal magnetic field for body heat and muscle pain changes. In conclusion, the Gaussian magnetic field of 1000G-1500G may affect body temperature and muscle pain in the elderly, and may have a significant impact on the quality of life in old age.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.2
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• pp.175-181
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• 2018

Electric pump system is new technology for next generation propulsion unit. The system has simple structure which dose not need gas generator, injector and turbine and might better pump for low cost and low payload rocket. Therefore, this paper suggests conceptual design of electric-pump Permanent-Magnet Synchronous Motor (PMSM) which has 50 kW & 50,000 RPM for rocket. To satisfy the system's requirement, electromagnetic analysis is conducted for suitable inner and outer diameter of stator and rotor which uses 4000 Gauss cylinder magnet and Inconel 718 can to fix whole rotor. Futhermore, to confirm rotational vibration, rotordynamics analysis is conducted. By this analysis, Campbell diagram is printed. From the diagram, natural frequency could be determined for the only motor and dynamo meter test bench.