• Physical Therapy Rehabilitation Science
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• 제11권3호
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• pp.329-334
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• 2022

Objective: Low back pain (LBP) is a symptom that accounts for a large proportion of musculoskeletal pain. Among them, non-specific LBP (NSLBP) means that the pathological cause is unknown, and belongs to the most common LBP. Studies on the mechanism of muscle control in LBP are insufficient, and quantitative studies are needed. Design: Observational cross-sectional study design Methods: A Thirty participants with NSLBP symptoms were enrolled, and their pressure pain thresholds (PPT) and muscle and fat thickness were measured. Participants measured the paraspinal muscles (PM) of the thoracic and lumbar spine and medial hamstring (semitendinosus) on the dominant and non-dominant sides in the prone position. Results: Among the variables that were significant in the correlation analysis, PM of the thoracic and lumbar spine showed a significant relationship in the PPT ([thoracic spine PM]=1.141+0.912 [lumbar spine PM]). Also, there was a significant relationship between the lumbar spine PM in the PPT and the thoracic spine PM in the muscle thickness ([lumbar spine PM of PPT]=4.057+0.117 [thoracic spine PM of muscle thickness]) Conclusions: Although there was no muscle imbalance according to the dominant and non-dominant side, there is a correlation between the pressure pain threshold and the muscle thickness between the paraspinal muscles of the thoracic spine and the lumbar spine.

• The Korean Journal of Physiology
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• 제9권1호
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• pp.63-68
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• 1975

Total body fat measurement by means of skinfold thickness was performed in 295 middle school girls in Suwon, Korea. Skinfold thicknesses on 4 sites, namely, arm, back, abdomen, and waist were obtained and fat was calculated using mean skinfold thickness (MSF) and the following formulas. % Fat=0.747$\times$MSF (mm)+l6.21 Fat (kg) =0.619$\times$MSF (mm) +3.31. The following results were obtained. 1. In 85 (age. 13 yr) of the first year class girls skinfold thickness was: arm 6.9mm; back 8.2; abdomen 8.3; waist 10.7mm, mean thickness was 8.5mm. Fat was 22.6$\pm$1.56% body weight or 8.20±2.68kg. Lean body weight was 31.93$\pm$3.16kg. 2. In 107 (age : 14.2 yr) of the second year class girls skinfold thickness was : arm 7.6mm; back 9.7; abdomen 9.7; waist 12.4mm; and mean thickness was 9.8mm. Fat was 23.0$\pm$5.09% body weight or 9.36$\pm$1.87kg. Lean body weight was 34.29$\pm$1.76 kg. 3. In 103 (age : 15.1 yr) of the third year class girls skinfold thickness was : arm 7.6mm; back 10.3; abdomen 9.4; waist 11.9mm; and mean thickness was 9.8mm. Fat was 23.2$\pm$4.35% body weight or 9.36$\pm$1.18 kg. Lean body weight was 37.10$\pm$5.08 kg. 4. The ratio of mean skinfold thickness (mm) to body weight (kg) was 0.213 in 13 year old girls, 0.225 in 14 year, and 0.213 in 15 year old girls.

• 농업과학연구
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• 제39권2호
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• pp.203-209
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• 2012

The objective of this study was to examine the effect of plasma leptin and insulin concentrations on fat traits in Hanwoo. If a biological indicator such as plasma leptin and insulin was identified, it would be a useful biological marker that can be predicted marbling score in young animal. The relationship between plasma hormone (leptin and insulin) and fat traits (marbling score, back fat thickness and P8 fat thickness) was investigated. The experiment studies 100 Hanwoo that were randomly sampled from Hanwoo Experimental Station Herd. The concentration of plasma insulin was significantly associated with marbling score (P=0.02) but was not significantly with back fat thickness (P=0.07) and P8 fat thickness (P=0.09). Statistical model determinant that plasma insulin concentration account for phenotypes was moderate on marbling score (5%), back fat thickness (3%) and P8 fat thickness (9%). On the other hand, plasma leptin concentration was significantly associated with marbling score (P=0.03) and back fat thickness (P=0.02), but was not significant on P8 fat thickness (0.07). Statistical model determinant that plasma leptin concentration accounting for phenotypes was moderate effect on marbling score (3%) and back fat thickness (2%), but it has a slightly bigger effect on P8 fat thickness (7%). In conclusion, the plasma leptin and insulin seems to have an effect on fat traits (marbling score, backfat thickness and P8 fat thickness) in Hanwoo.

• Design & Manufacturing
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• 제16권1호
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• pp.27-35
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• 2022

Thermoforming is a plastic manufacturing process that applies a force to stretch a film of heated thermoplastic material over an engineered mold to create a 3-dimensional shape. After forming, the shaped part can then be trimmed and finished to specification to meet an end-user's requirements. The process and thermoplastic materials are extremely versatile and can be utilized to manufacture parts for a very wide range of applications. In this study, based on K-BKZ nonlinear viscoelastic model, thermoforming process analysis was performed for an interior room-lamp. The predicted thickness was minimum at the corner of a molded film, and maximum at the center of the bottom. By using the Taguchi method of design of experiments, the effects of process conditions on residual stresses were investigated. The dominant factors were the liner thickness and the film heating time. As the thickness of the liner increased, the residual stress decreased. And it was found that the residual stress decreased significantly when the film heating temperature was higher than the glass transition temperature. A thermoforming mold and a trimming mold were manufactured, and the spring back was investigated through experiments. The dominant factors were film heating time, liner thickness, and lower mold temperature. As the film heating time and liner thickness increased, the spring back decreased. In addition, it was found that the spring back decreased as the lower mold temperature increased.

• 대한정형도수물리치료학회지
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• 제29권1호
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• pp.53-67
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• 2023

Background: This study comparatively evaluated the effects of equipment-based pilates exercises (EPE) and lumbar stability exercises (LSE) in patients with chronic low back pain in terms of their Visual Analogue Scale(VAS), Oswestry Disability Index(ODI), and abdominal muscle thickness. Methods: A total of 30 participants were recruited and randomly assigned to either the EPE or the LSE. The VAS, ODI, and abdominal muscle thicknesses of the participants were measured before and after the intervention. Results: The EPE were more effective in terms of the duration of a sustained reduction in VAS scores. post hoc test revealed that EPE were more efficacious in terms of a sustained improvement in ODI scores. With respect to changes in abdominal muscle thickness, there was a significant difference in the thickness of internal oblique muscles(IO) and the external oblique muscles(EO) between the two groups. Conclusion: In this study, both types of exercise interventions resulted in improvements in the VAS, ODI scores, and abdominal muscle thickness in patients with chronic low back pain. However, EPE were found to be more effective than LPE in terms of longer sustained improvements in VAS and ODI scores. Also, with respect to abdominal muscle thickness, the thickness of EO and IO improved only in the EPE group.

• 한국정밀공학회지
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• 제25권9호
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• pp.38-44
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• 2008

Light guide plate is one of most important components which are composed of back light unit, affecting the quality and performance of LCD. Average brightness and uniformity are especially key factors for designing the light guide unit. These qualities are affected and controlled by the pattern being attached to the back of light guide unit. In order to obtain high brightness and uniformity the optimized pattern design is adopted for LGP. In this study, optimized molding condition for LGP with 0.4 mm thickness was obtained by using the Moldflow simulation software and the optimized pattern for better brightness uniformity was designed for the thickness of the 0.4 mm by trial and error method. The brightness was measured for the different LGP thicknesses and the residual stress analysis was performed for 0.4 mmthickness by the photoelasticity and the results are compared with 0.5 mm, 0.6 mm thickness.

• 한국정밀공학회지
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• 제24권6호
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• pp.58-65
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• 2007

The arbitrarily-bended pipe is widely used in a heat exchanger system. Thus, the pipe bending process has important role in performance and productivity of heat exchanger system. The purpose of this study is to investigate the bending process for manufacturing of sound pipe. And, the spring-back effect and the variation of pipe thickness should be controlled effectively. The change of spring-back ratio and the thickness variation of pipe according to the change of bending radius, bending angle and pipe thickness are analyzed by FEM analysis. The analytic results are compared with the experimental data, accordingly the results show good agreement. The method of the analysis can be applied for manufacturing of precision bended pipe.

• 농업과학연구
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• 제50권4호
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• pp.595-602
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• 2023

Feed processing methods can substantially enhance the nutrient value of feed. The aim of our study was to compare the effects of mash or crumble feed on growth performance, nutrient digestibility, back-fat thickness, and carcass quality of growing-finishing pigs. In total, 50 ([Landrace × Yorkshire] × Duroc) growing pigs with initial body weight of 46.24 ± 3.57 kg were randomly assigned to two dietary treatment groups. The two dietary treatments were: 1) mash and 2) crumble feed forms for 14 weeks of trials. Five replication pens per treatment, comprised five pigs (2 males and 3 females) each. Growth performance, nutrient digestibility, back-fat thickness, and carcass quality were observed at different weeks. There were no significant differences in growth performance, nutrient digestibility, back-fat thickness, and carcass quality throughout the experimental trial. Further study is required to understand the effects of mash and crumble feed on growing-finishing pigs.

• 대한물리치료과학회지
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• 제26권3호
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• pp.23-36
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• 2019

Background: The purpose of this study was to investigate the effect of Plank exercise on unstable support surfaces on flexibility, abdominal muscle thickness and pain in patients with chronic back pain. Design: Randomized controlled trial. Methods: This study was performed on 16 patients with chronic back pain of ◯◯ military unit. Sixteen subjects were randomly assigned into two groups, an upper extremity trainer group (group I, n=8) and a lower extremity trainer group (group II, n=8). The subjects in group I carried out Flank exercise applying the stability trainer to their upper extremities and ones in group II carried out the same exercise applying the stability trainer to their lower extremities for 4 weeks. In order to ascertain the difference between two groups, flexibility, abdominal muscle thickness and pain were measured before and after the exercise. The flexibility was measured by sit and reach test, the thickness of the abdominal muscle was measured by using ultrasonic imaging equipment, and the pain was measured by the visual analogue scale. A paired t-test was utilized to compare changes in pain, abdominal muscle thickness and flexibility before and after flank exercise on unstable support surfaces. Analysis of Covariance (ANCOVA) was performed for ascertaining the significant differences between groups. The significance level was set by α=.05. Results: 1) The flexibilities of two groups were increased after the exercise (p<0.05). 2) In both groups, the thicknesses of rectus abdominis, external oblique abdominis, internal oblique abdominis, and transverse abdominis were all increased after the exercise (p<0.05). 3) The pains in both groups were decreased after the exercise (p<0.05). 4) In the comparisons of two groups, there were no differences in the flexibility, thickness of external oblique abdominis, internal oblique abdominis and transverse abdominis and pain (p>0.05). Whereas only thickness of Rectus abdominis was larger in the group I than in the group II (p<0.05). Conclusion: Plank exercise on the unstable support surface for 4 weeks resulted in increased flexibility, abdominal muscle thickness and pain reduction in patients with chronic back pain. Therefore, it is considered that performing flank exercise on the unstable supporting surface is suitable for the reduction of the pain in patients with chronic back pain. However, in this study, it is considered that continuous and diverse studies are needed because there was not a large difference between the groups when the upper or lower limbs are provided unstable support surfaces.

• 한국재료학회지
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• 제23권9호
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• pp.495-500
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• 2013

Mo-based thin films are frequently used as back electrode materials because of their low resistivity and high crystallinity in CIGS chalcopyrite solar cells. Mo:Na/Mo bilayer thin films with $1{\mu}m$ thickness were deposited on soda lime glass by varying the thickness of each layer using dc-magnetron sputtering. The effects of the Mo:Na layer on morphology and electrical property in terms of resistivity were systematically investigated. The resistivity increased from $159{\mu}{\Omega}cm$ to $944{\mu}{\Omega}cm$; this seemed to be caused by increased surface defects and low crystallinity as the thickness of Mo:Na layer increased from 100 nm to 500 nm. The surface morphologies of the Mo thin films changed from a somewhat coarse fibrous structures to irregular and fine celled structures with increased surface cracks along the cell boundaries as the thickness of Mo:Na layer increased. Na contents varied drastically from 0.03 % to 0.52 % according to the variation of Mo:Na layer thickness. The change in Na content may be ascribed to changes in surface morphology and crystallinity of the thin films.