• 한국운동역학회지
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• 제15권4호
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• pp.153-168
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• 2005

The purposes of this study were to determine the influence of midsole hardness and sole thickness of sports shoes on ball flex angle and position with increment of running velocity. The subjects employed for this study were 10 college students who did not have lower extremity injuries for the last one year and whose running pattern was rearfoot striker of normal foot. The shoes used in this study had 3 different midsole hardness of shore A 40, shore A 50, shore A 60 and 3 different sole thickness of 17cm, 19cm, 21cm. The subjects were asked to run at 3 different speed of 2.0m/sec, 3.5m/sec, 5.0m/sec and their motions were videotaped with 4 S-VHS video cameras and 2 high speed video cameras and simultaneously measured with a force platform. The following results were obtained after analysing and comparing the variables. Minimum angle of each ball flex position were increased with the increment of running velocity and shoe sole thickness(P<0.05), but mid-sole hardness did not affect minimum ball flex angle. The position which minimum angle was shown as smallest was 'D'. Midsole hardness and sole thickness did not affect time to each ball flex minimum angle, total angular displacement of ball flex angle, and total angular displacement of torsion angle(P<0.05). The position which minimum angle was appeared to be earliest was similar at walking velocity, and E and F of midfoot region at running velocity. Total angular displacement of ball flex position tended to increase as shifted to heel. It was found that running velocity had effects on ball flex angle variables, but shoe sole thickness partially affected. It would be considered that running velocity made differences between analysis variables at walking and running when designing shoes. Also, it was regarded that shoes would be developed at separated region, because ball flex angle and position was shown to be different at toe and heel region. It is necessary that midsole hardness and thickness required to functional shoes be analyzed in the further study.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.306-311
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• 2001

Effect of boundary layer thickness on the flow characteristics around a rectangular prism has been investigated by using a PIV(Particle Image Velocimetry) technique. Three different boundary layers(thick, medium and thin)were generated in the Atmospheric Boundary Layer Wind Tunnel at Pusan National University. The thick boundary layer having 670mm thickness was generated by using spires and roughness elements. The medium thickness of boundary layer$(\delta=270mm)$ was the natural turbulent boundary layer at the test section with fully long developing length(18m). The thin boundary layer with 36.5mm thickness was generated by on a smooth panel elevated 70cm from the wind tunnel floor. The Reynolds number based on the free stream velocity and the height of the model was $7.9{\times}10^3$. The mean velocity vector fields and turbulent kinetic energy distribution were measured and compared. The effect of boundary layer thickness is clearly observed not only in the length of separation bubble but also in the reattachment points. The thinner boundary layer thickness, the higher turbulent kinetic energy peak around the model roof. It is strongly recommended that the height ratio between model and approaching boundary layer thickness should be a major parameter.

• 한국임상보건과학회지
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• 제5권4호
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• pp.1021-1025
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• 2017

Purpose: Changes in corneal thickness after wearing hydrogel lens and silicone-hydrogel lens with different oxygen transmission rates wew syudied. Methods: Experiments were performed on 11 subjects(22 eyes). corneal thickness was measured after wearing contact lenses for 8 hours. Corneal thickness was measured using ORB Scan II(ver. 3.14) Results: In the results of the corneal thickness measurement by direction, in the case of the hydrogel-tor lens, the center thickness was $33.63{\mu}m$, the nasal was $34.29{\mu}m$, the temporal was $27.17{\mu}m$, the inferior was $27.17{\mu}m$, the superior was $18.90{\mu}m$, and change rates were 6.28%, 5.71%, 5.40%, 4.75% and 3.09%, respectively. In the results of the corneal thickness measurement by diameter, in the case of the hydrogel-tor lens, the center was $33.63{\mu}m$, the mid-peripheral was $28.19{\mu}m$, the peripheral was $24.18{\mu}m$, and change rates were 6.28%, 4.76%, and 3.79%, respectively. Conclusions: The hydrogel lenses with relatively low oxygen transmission rates resulted in a significant increase in thickness over the entire cornea compared to silicon-hydrogel lenses with high oxygen transmission rates.

• 대한물리의학회지
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• 제8권2호
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• pp.263-269
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• 2013

PURPOSE: The purpose of this study was to examine the effects of breathing retraining on asymmetry of diaphragm thickness in stroke patients. METHODS: This study was nonequivalent control group pre-post test design. Subjects were assigned to two different groups(intervention group=10, control group=12). Intervention group conducted breathing retraining program for six-week. Diaphragm thickness was assessed by ultrasound in B-mode with a 7.5 MHz linea probe. The collected data analyzed by Wilcoxon signed rank test and Mann-Whitney U test. RESULTS: The intervention group significantly increased diaphragm thickness ratio on paretic side but the control group showed no significant difference in diaphragm thickness ratio. The control group significantly increased asymmetry of diaphragm thickness, but intervention group showed no significant difference in asymmetry of diaphragm thickness. CONCLUSION: This study showed that breathing retraining increased diaphragm thickness ratio in stroke patients and prevent the increase of asymmetry in diaphragm thickness with stroke patients.

• Journal of Welding and Joining
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• 제17권1호
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• pp.133-144
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• 1999

To fine seam annealer capacity of through thickness seam annealing in terms of through thickness microstructure change with increased toughness and elongation leaving heat trace on it, high strength steel pipes of ERW with different thickness were tested in different seam annealing temperature measured on the outer surface of pipes. Annealing temperature and microstructure of the weld seam were changed through applied seam annealing condition. Toughness and tensile test with hardness and microstructure analysis were done on the annealed weld seam to fine its characteristics as a primary step and annealing characteristics according to different seam annealing condition. Through a study of annealed ERW weld seam characteristics and seam annealing technology, amount of electric power should apply in decreased manner to arranged inductors of annealer in the order of 1st, 2nd, 3rd, so on for proper seam annealing. For example of 15.4mm thick and 610mm outside diameter pipe, applied power for proper seam annealing is 600 -650kw at 1st inductor, 450 - 500kw at 2nd inductor, 200-250 kw at 3rd inductor of annealer during 10 - 12M/minute moving speed of pipe. Also, the penetration depth of heat trace along the thickness direction of weld during seam annealing can be estimated through the equation 17mm/kv$\times$voltage(kv) with the microstructure and hardness analysis of thick weld seam as well as study of seam annealing and comparison of cooling condition to CCT diagram of low carbon high strength steel. From this result, the difference between the technological applicability of full annealing condition based on phase diagram and full penetration of heat trace based on CCT diagram along the thickness of weld seam is discussed.

• Physical Therapy Rehabilitation Science
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• 제7권2호
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• pp.72-77
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• 2018

Objective: This study aimed to compare the effects of core exercise methods on muscle activation and muscle thickness in healthy young adults and to propose effective core exercise methods. Design: Three-group pretest-posttest design. Methods: A total of 30 healthy young adults (14 males, 16 females) voluntarily participated in the study. Subjects were randomized to the prone plank exercise (n=10), reverse plank exercise (n=10), or bridge exercise (n=10) groups. Muscle activity and thickness of the rectus abdominis (RA), multifidus (MF), external oblique (EO), and internal oblique (IO) muscles were measured using surface electromyography and ultrasound. Subjects from each group participated in the exercises five times a week, with five 20-second sets during week 1. The set time was increased by 10 seconds per week. Results: Muscle activity and thickness in the prone plank, reverse plank, and bridge exercise group were statistically significant different for RA, MF, EO, and IO changes over time, and interaction between time and groups were also significantly different (p<0.05). We analyzed statistically significant differences between groups using a one-way analysis of variance for each period. A significant difference was observed after 4 weeks of exercise (p<0.05). Conclusions: The results suggest that the prone plank exercise is a beneficial method for enhancing muscle activation and thickness of the RA, EO, and IO compared to the reverse plank and bridge exercises. On the other hand, the reverse plank and bridge exercises are effective methods for enhancing the MF compared to the prone plank exercise.

• 대한물리치료과학회지
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• 제29권3호
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• pp.48-55
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• 2022

Background: The purpose of this study is to examine the effect of push-up plus exercise on the changes in the thickness of the trapezius trapezius, serratus anterior and pectoralis major muscles involved in shoulder stability in various support surfaces. Design: Randomized controlled trial. Methods: The thickness change of the shoulder stabilizing muscle was measured using an ultrasound device. Corresponding t-test was performed to confirm the change within the group before the experiment and after 5 weeks. And one-way ANOVA was used to confirm the change between groups after 5 weeks. As a post hoc test, the least significant difference test was performed, and the significance level was set to a=0.05. Results: Changes in the thickness of the trapezius muscle within the group were significantly different between UPEG and SPEG after 5 weeks (p<0.05), and there was a significant difference between groups after 5 weeks (p<0.05). Changes in the thickness of the serratus anterior and pectoralis major muscle within the group were significantly different after 5 weeks in PEG, UPEG and SPEG (p<0.05), and the changes between the groups were significantly different in the serratus anterior muscle after 5 weeks (p<0.05). Conclusion: From the results of this study, it was found that the push-up exercise on an unstable support surface was effective for strengthening the trapezius upper and serratus anterior. This study intends to suggest the possibility of application as basic data for a push-up plus exercise program in clinical practice.

• 한국전문물리치료학회지
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• 제19권3호
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• pp.1-10
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• 2012

The aim of this study is to compare measurements of abdominal muscle thickness using ultrasonography imaging (USI) to those using a special transducer head device, during five different trunk stabilization exercises, ultimately to determine which exercise led to the greatest muscle thickness. Thirty eight healthy subjects participated in this cross-sectional study. The five types of trunk stabilization - i.e., a sit-up on the supine, an upper and lower extremity raise with quadruped on the prone, a leg raise in sitting on the ball, trunk rolling on the ball, and balance using sling on the prone position - were each performed with an abdominal draw. The thickness of the abdominal muscle - including the transverse abdominal (TrA), internal oblique (IO), and external oblique (EO) - was measured by USI with a special transducer head device, at rest and then at contraction in each position. Data were analyzed using one-way repeated ANOVA with the level of significance set at ${\alpha}$=.05. The results were as follows: 1) the TrA thickness was statistically significant (p<.05), whereas the IO and EO thicknesses were not (p>.05); 2) among the five types of trunk stabilization, TrA thickness significantly increased with the balance using a sling in the prone position, (p<.05), whereas no significant difference was noted for the four types of trunk stabilization (p>.05); 3) reliability data showed that there was a high degree of consistency among the measurements taken using the special transducer head device (ICC=.92). In conclusion, the balance using a sling in the prone position was more effective than any of the four other types of trunk stabilization in increasing TrA thickness in healthy subjects.

• 한국가구학회지
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• 제21권6호
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• pp.449-458
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• 2010

본 연구는 중밀도섬유판(MDF)의보드두께에 따른 수평밀도분포(HDD: horizontal density distribution)를 조사하기 위해 수행하였다. 생산공장에서 제조된 보드두께가 다른 5 종류 즉 2 mm, 4.5 mm, 9 mm, 18 mm 및 30 mm의 원판을 두 가지 다른 시편크기 즉 $500{\times}500\;mm$와 $120{\times}120\;mm$로 제작하여 수평밀도분포를 측정하였다. 전체적으로MDF의 밀도는 보드두께가 증가할수록 감소하는 경향을 보였으며, 가장 얇은 보드두께의 MDF가 가장높은 밀도를 나타내었다. 수평밀도분포의 변이는 작은 크기 즉 $120{\times}120\;mm$의 시편에서 큰 차이를 보여 MDF의 보드두께가 수평밀도분포에 큰 영향을 미치는 것으로 나타났으며 보드두께가 클수록 감소하는 경향을 나타내었다. 또 보드두께가 적을수록 수평밀도분포의 밀도분포는 컸으나 보드두께가 클수록 밀도범위가 좁게 나타났다. 수평밀도분포의 변이계수(COV)는 보드두께가 증가함에 따라 감소하는 경향을 보였다. 요약하면 MDF 보드두께는 수평밀도분포에 매우 큰 영향을 미치며시편의 크기 또한 상당한 영향을 미치는 것으로 나타났다.

• The Journal of Korean Physical Therapy
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• 제27권1호
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• pp.50-54
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• 2015

Purpose: The purpose of this study is to investigate differences of cervical flexor muscle thickness (i.e., sternocleidomastoid muscle and deep cervical flexor muscles) depending on levels of pressure bio-feedback unit and eye directions during cranial-cervical flexor exercise in healthy subjects. Methods: A total of 30 subjects (12 males and 18 females) who had no medical history related to musculoskeletal and neurological disorders were enrolled in this study. They were instructed to perform cranial-cervical flexion exercise with adjustment of five different pressures (i.e., 22 mmHg, 24 mmHg, 26 mmHg, 28 mmHg, and 30 mmHg) using a pressure biofeedback unit, according to three different eye directions (i.e., $0^{\circ}$, $20^{\circ}C$, and $40^{\circ}C$). Muscle thickness of sternocleidomastoid muscle and deep cervical flexor muscles was measured according to pressure levels and eye directions using ultrasonography. Results: In results of muscle thickness in sternocleidomastoid muscle and deep cervical flexor muscles, the thickness of those muscles was gradually increased compared to the baseline pressure level (22 mmHg), as levels in the pressure biofeedback unit during cranial-cervical flexion exercise were increasing. In addition, at the same pressure levels, muscle thickness was increased depending on ascending eye direction. Conclusion: Our findings showed that muscle thickness of sternocleidomastoid muscle and deep cervical flexor muscles was generally increased during cranial-cervical flexion exercise, according to increase of eye directions and pressure levels. Therefore, we suggested that lower eye direction could induce more effective muscle activity than the upper eye direction in the same environment during cranial-cervical flexion exercise.