• The Journal of Korean Physical Therapy
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• v.22 no.6
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• pp.7-12
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• 2010

Purpose: This study investigated changes in the thickness of the transversus abdominis (TrA), internal abdominal oblique (IO), and external abdominal oblique (EO) muscles between crook lying and wall support standing positions during abdominal hollowing (AH), using ultrasound imaging. Methods: Experiments were conducted on 20 healthy male adults (mean age=$22.45{\pm}4.08$ years) who voluntarily agreed to participate in the experiments. The changes in the thickness of the subjects' abdominal muscles were measured during AH in crook lying and wall support standing positions. Results: The difference in the thickness of TrA between the two positions during AH was statistically significant, but the differences in the thicknesses of IO and EO were not significant. Conclusion: Activity of the TrA, which is a deep muscle, was stimulated in the standing position, which is, therefore, more functional than the crook position, but the activities of IO and EO muscles did not decrease. Therefore, various methods to induce the activity of TrA while decreasing the activities of IO and EO, in the functional standing position that can stimulate deep muscles, need to be designed.

• The Journal of Korean Physical Therapy
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• v.30 no.2
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• pp.41-46
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• 2018

Purpose: This study examined the effects of knee extension exercise using blood flow restriction on the changes in the thickness and static balance ability of the tendon of the rectus femoris muscle and achilles tendon. Methods: A total of 30 subjects was were divided into two groups of 15 subjects each. The changes in the thickness and balance of their tendons were measured by ultrasonography and balance equipment. The measurements were taken three times: before the experiment, 4 weeks after, and 8 weeks after. The results were analyzed by repeated measure ANOVA, one-way ANOVA was conducted in cases where there were time-to-group interactions in the intra-individual effects test. Results: Significant differences in the thickness of the tendon of the rectus femoris muscle and Achilles tendon were found between the groups, over time, and in the time-to-group interactions (p<0.05). The changes in balance in both feet when the supporting positions between eye-open and eye-closed states were significantly different in the time-to-group interactions (p<0.05), but were not different between the groups (p>0.05). Conclusion: Knee extension exercise using blood flow restriction leads to significant differences in the increase in tendon thickness and changes in balance, indicating that the results of this study can be utilized as basic data for future studies and for rehabilitation treatment at clinics.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.14 no.1
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• pp.51-59
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• 1984

The aim of this study was to investigate the thickness of angular cortex and bone density of mandible in normal person. Age changes and sex differences of those were comprised in this study. Material included 456 pantomographic views and 309 intraoral films taken by paralleling technic. 1. Conclusions from this study were as follows. The thickness of mandibular angular cortex increased with age in both sexes before 15 to 19-year-old group. And those were relatively constant in the age range from 20 to 49 years in male and in the age range from 20 to 39 years in female, but decreased after that age. 2. The thickness of mandibular angular cortex were larger in male than in female. And no significant differences between sexes were noted before 40 to 49-year-old group. 3. Changes of bone density with age were analogous to changes of thickness of mandibular angular cortex. Correlation coefficients between changes of bone density and age were arranged, and male group underwent comparatively low correlation while insignificant statistically in female gruop. And no significant differences between sexes were found in all age groups except 50 to 59-year-old group.

• The Journal of Korean Physical Therapy
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• v.28 no.2
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• pp.112-118
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• 2016

Purpose: This study examined thickness changes in abdominal muscles according to difficulty level of core stabilization exercise in healthy subjects. Methods: Thirty healthy subjects (age range: 21-30 years) volunteered under three conditions. In the first condition, the subjects performed an abdominal draw-in maneuver (ADIM). In the second condition, they performed the ADIM during quadruped exercise using a suspension device without extending their lower limbs. In the third condition, the subjects performed the ADIM during quadruped exercise using a suspension device while extending both lower limbs. The changes in thickness of transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) muscles were measured by ultrasonography (US) imaging during the three experimental conditions, and US was used to measure the improvement ratio of muscle thickness at rest. The interventions were conducted over three trials in each condition, and measurements were performed on each subject by one examiner. Results: Our results showed a significantly greater increase in the muscle thickness of TrA and IO muscles after performance of quadruped exercise using a suspension device without knee extension (p<0.05) compared to the other conditions. The results also showed a significantly greater increase in the thickness changes of EO muscle in those who performed the ADIM during quadruped exercise using a suspension device with knee extension (p<0.05) compared with the ADIM only. Conclusion: These findings demonstrated positive evidence that a low-level core stabilization exercise could improve thickness of abdominal muscles.

• Journal of the Korean Society of Physical Medicine
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• v.10 no.1
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• pp.71-82
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• 2015

PURPOSE: The aim of this study is to compare changes in the thickness of the gluteus medius muscle fiber between chronic low back pain(clbp) with gluteus medius weakness and healthy subject. METHODS: Ultrasound imaging was used to measure in the thickness of each fiber of the gluteus medius muscle based on maximal muscle contraction during abduction motion of the hip joint in a healthy group (11 subjects) and a chronic CLBP group (21 subjects). An independent t-test was performed to analyze the difference of thickness in each fiber of the gluteus medius muscle and the rate of changes in the fibers in the two groups. RESULTS: The fiber thickness changes in the gluteus medius muscle were significantly lower for the posterior fiber in the CLBP group compared to the healthy group (p<0.01). The changes in rate of difference of thickness the posterior part of the gluteus medius muscle was significantly lower in the CLBP group than in the healthy group (p<0.05). CONCLUSION: The findings of this study CLBP patients with weakness of the gluteus medius muscle that lower for the posterior fiber's difference of thickness and rate of change in the CLBP group compared to the healthy group. Indicate that rehabilitation of CLBP patients with weakness of the gluteus medius muscle should consider the functions of posterior fiber of the gluteus medius muscle.

• Journal of Magnetics
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• v.6 no.1
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• pp.19-22
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• 2001

Change of magnetic properties in CoCrPt/Ti perpendicular media with varying CoCrPt film thickness has been studied. As the CoCrPt film thickness increases from 25 nm, the Ms (saturation magnetization) increases rapidly at first and then more gradually. This Ms behavior is associated primarily with the formation of an "amorphous-like"reacted layer created by intermixing of CoCrPt and Ti at the CoCrPt/Ti interface and secondarily with a change of the Cr segregation mode with varying CoCrPt film thickness. Magnetic domain structure distinctively changes with increasing CsCrPt magnetic layer (ML) thickness. Also the strength of exchange coupling measured from the slope in the demagnetizing region of the M-H loop changes with ML thickness. The expansion of lattice parameters a and c at smaller film thickness suggests that the Cr segregation mode may be connected with the residual stress of the films. Finally, the negative nucleation field (Hn) shows a unique behavior with the change of strength of the exchange interaction.teraction.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.218-226
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• 1996

This study was performed to evaluate the possibility of pulpal damage by measuring temperature change occured in dentin according to the thickness of dentin, the time of irradiation and the output of laser energy when the dentin surfaces were irradiated with Nd-YAG laser under water coolant and no water coolant. Sound upper and lower molar teeth were sectioned with 1mm, 1.5mm and 2mm thickness of dentin discs and divided into 4 groups by dentin thiness. 0.5 watt, 1 watt, 1.5 watt and 2 watt-energied beam of pulsed 10 p.p.s of Nd : YAG laser was applied respectively to dentin surfaces for 8 secs and 16 secs when water coolant is used or not.Ant then the temperature changes occurd in dentin were measured at opposite surfaces of laser-irradiated dentin surfaces with digital thermometer. The results were as follow. 1. When the amount of irradiated energy was same, the temperatue changes of dentin were higher as the thickness of dentin discs was thinner(p<0.01). 2. When the amount of irradiated energy and the thickness of dentins were same, The temperature changes of dentin were lower under water coolant than under no water coolant in all groups(p<0.01). 3. With the increase of time of irradiation, the temperature changes of Dentin became higher in all groups and were steeply increased at initial period of irradiation of laser. 4. Under the same thickness of dentin, the temperature changes of dentin became higher as irradiated energy was increased. These results suggest that when the beam of Nd : YAG Laser is irradiated to dential hard tissue, amount of irradiating energy, thickness of dentin, using water coolant must be considered in order to minimize thermal damage of the pulp.

• Nuclear Engineering and Technology
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• v.54 no.9
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• pp.3272-3282
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• 2022

To improve the safety and life extension qualities of nuclear fuel rods which is currently made of zirconium (Zr) alloy, research on the application of chromium (Cr) coating was conducted. Cr coating has advantages such as increased corrosion resistance and reduced oxidation rate, but non-destructive thickness evaluation studies are needed to ensure the reliability of the steps taken to provide uniform coating thickness. Eddy current testing (ECT) is a representative non-destructive technique for such as thickness evaluation and surface defect inspection. To inspect changes in thickness at micron scale, the Swept Frequency Eddy Current Testing (SFECT) method was applied to select a frequency range sensitive to changes in thickness. The coating thickness was evaluated using changes in signals, such as that for impedance. In this study, basic research was performed to evaluate the thickness of the Cr coating on a rod using an encircling sensor and the SFECT technique. The sensor design parameters were determined through simulation, after which the new sensor was manufactured. A sensor capable of measuring the thickness of a non-uniformly Cr-coating rod was selected through an experiment evaluating the performance of the manufactured sensor. This was done using the impedance-difference of a Cr-coating rod and a Zr alloy rod. The possibility of evaluation of the Cr coating thickness was confirmed by comparing the experimental results with the selected sensor and the signals of the measured Cr-coating rod. All simulation results were verified experimentally.

• Journal of the Korean Society of Physical Medicine
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• v.6 no.3
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• pp.287-292
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• 2011

Purpose :The present study invesigated the effect of changes in transversus abdominis thickness using ultrasonography during a hip adductor contraction. Methods : This study was carred out in a volunteer sample of adults (N=30) without a history of low back pain or injury. In standing position, muscle thickness measurements of transversus abdominis(TrA) were measured using ultrasonography at rest and during a hip adducor contraction. Results : TrA thickness were influenced a hip adductor during a voluntary contraction in people without LBP. TrA showed significantly greater thickness changes on a hip adductor contraction.(p=0.000) Conclusion : The results from this study showed that the hip adductor contraction improves the ability to increase change in TrA thickness. These results can be a good evidence to prevent low back pain due to hip adductor weakness or genu varum deformity of knee osteoarthritis.

• Journal of Biomedical Engineering Research
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• v.34 no.2
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• pp.80-90
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• 2013

Recently, functional insoles of wedge-type it is for the young to raise their height inserted between insole and heel cause foot pain and disease. Additionally, these have a problem with stability and excessively load-bearing during gait like high-heel shoes. In this study, we compared the changes in biomechanical characteristics of foot with different insole thickness then we will utilize for the development of the insole with the purpose of relieving the pain and disease. Subjects(male, n = 6) measured COP(center of pressure) and PCP(peak contact pressure) on the treadmill(140cm/s) using F-scan system and different insole thickness(0~50 mm) between sole and plantar surface during gait. Also, we computed changes of stresses at the foot using finite element model with various insole thickness during toe-off phase. COP moved anterior and medial direction and, PCP was increased at medial forefoot surface, $1^{st}$ and $2^{nd}$ metatarsophalangeal, ($9%{\uparrow}$) with thicker insoles and it was show sensitive increment as the insole thickness was increased from 40 mm to 50 mm. Change of the stress at the soft-tissue of plantar surface, $1^{st}$ metatarsal head represents rapid growth($36%{\uparrow}$). Also, lateral moments were increased over the 100% near the $1^{st}$ metatarsal as the insole thickness was increased from 0 mm to 30 mm. And it is show sensitive increment as the insole thickness changed 10 mm to 20 mm. As a result, it was expected that use of excessively thick insoles might cause unwanted foot pain at the forefoot region. Therefore, insole thickness under 30 mm was selected.