• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.3
• /
• pp.12-18
• /
• 2014

This paper describes about the development of new concept's rear wheel guards for the reduction of Road Noise in the passenger vehicle using test. The new wheel guards are proposed by various frequency chamber concept and different textile layers concept. Two wheel guards were verified by small cabin resonance test and vehicle test. Through new developing process without vehicle test, Result of road noise will be expected when new concepts and materials of wheel guard is applied into automotive vehicle. As a result of the application of Aimed Helmholtz and Multi-layers concept, this paper classifies the road noise, cost and weight are reduced by new concepts and the solutions are adopted into the 2 cars.

• Economic and Environmental Geology
• /
• v.50 no.6
• /
• pp.487-495
• /
• 2017

A granite rock body, called 'Bukbawi', located on a mountaineering trail at Mt. Palgong Provincial Park is popular among the public because it resembles a percussion instrument. If someone hits the specific surface area of this rock body, people can hear drum-like sound. Such phenomenon may be geologically associated with exfoliation process of the granite body or miarolitic cavity developed after gasses escaped during formation of granite. To understand better the inner structure causing drum-like sound, we carried out a non-destructive ground-penetrating radar survey. In this study, as our primary target is very close to the surface, we utilized 1 GHz antennas to produce high-resolution near-surface images. In order to construct 3-D internal images, the measurements were conducted along a pre-defined grid. The processed radargrams revealed that the locations associated with 'drum' sound coincide with strong reflections. In addition, both reflection patterns of fracture and cavity were observed. To further quantify the observed reflections, we simulated GPR scans from a synthetic fracture in a granite body, filled with different materials. The simulated results suggest that both exfoliation process and miarolitic cavity may have contributed to the 'drum' phenomena. Furthermore, the radargrams showed a well-developed cavity signature where two major reflection planes were crossed. Thus, our study is an example of non-destructive geophysical studies that can promote Earth Science in the broader community by examining geological structures attracting the public.

• Journal of the Korean Orthopaedic Association
• /
• v.55 no.4
• /
• pp.318-323
• /
• 2020

Purpose: To examine the relationship between total fat infiltration (TFI) rate, which quantifies the reduction of muscles around the spine and is an important factor for sarcopenia, and the factors affecting osteoporotic vertebral compression fracture. Materials and Methods: Patients treated for osteoporotic compression fractures of the lumber spine from January 2012 to December 2016 were analyzed retrospectively. Among them, this study included ninety-eight patients who were 1) diagnosed with osteoporosis with a bone mineral density (BMD) T score of less than 2.5 g/cm², 2) received vertebroplasty or kyphoplasty for lumbar fractures, 3) involved one segment of the lumbar spine, and 4) were followed-up for more than one year. The TFI rate confirmed by analyzing magnetic resonance imagings with the Image J program was studied. Based on this, the relationship between the TFI of the multifidus and erector spinae muscles and the factors of osteoporosis were analyzed. Results: The mean TFI of the multifidus and erector spinae was 14.66±10.16. The spine BMD showed a positive correlation with the hip BMD, but a negative correlation with the TFI. A positive correlation was observed between the hip BMD and body mass index. In addition, vitamin D was positively correlated with both the hip and spine BMD but negatively correlated with the TFI rate. Conclusion: Muscle growth helps treat osteoporosis, and can prevent fractures that occur frequently in osteoporosis patients. Increasing the vitamin intake can also slow the progression of muscle atrophy.