• Journal of The Korean Society of Integrative Medicine
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• v.2 no.1
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• pp.35-49
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• 2014

Purpose : The purpose of this study was to find the effects of the lumbar stabilization exercise and strength exercise on pain, ROM, strength, muscle thickness of low back pain(LBP) patients. Method : The subjects were consisted of twelve patients who had nonspecific LBP. All subjects randomly assigned to lumbar stabilization exercise group(N=6) and strength exercise group(N=6). We measured muscular strength, ROM by using Tergumed-extension, rotation and muscle thickness by using ultrasonography and pain score by using Visual analog scale(VAS). The lumbar stabilization exercise group received TOGU exercise, strength exercise group received Tergumed exercise. The data analyzed by repeated measure of Independent t-test, paired t-test, reliability test. Result : The results were as follows. The result which measured of the change of pain score was a significant decrease. The result which measured of the change of ROM and strength was a significant increase. The result which measured of the change of the Internal abdominal oblique, External abdominal oblique on muscle thickness was a significant increase. Stabilization exercise group and Strength exercise group showed the significant difference in muscle thickness on Transversus abdominis, Multifidus. Stabilization exercise group was more increased in muscle thickness. Conclusion : Therefore, we suggest that stabilization exercise is effective for non-specific low back pain.

• Physical Therapy Rehabilitation Science
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• v.3 no.2
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• pp.93-100
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• 2014

Objective: The purpose of this study was to determine the effect of the abdominal bracing (AB) and abdominal bracing combined with ankle dorsiflexion (ABDF) on abdominal muscle thickness and strength in patients with chronic low back pain (LBP). Design: Two group pretest posttest design. Methods: Sixteen subjects were divided randomly into two group: ABDF group (n=8), and alone AB group (n=8). The ABDF group practiced AB exercise with additional ankle dorsiflexion. AB group practiced only AB exercises. Subjects in both groups received ABDF exercise and AB exercise for 40 min per day, three days per week during a period of three weeks, respectively. All the subjects were evaluated for abdominal muscle thickness and strength before and after intervention using ultrasonography and MedX machine. Results: The external oblique (EO), internal oblique, transverse abdominis (TrA) muscle thickness and the strength produced at $48^{\circ}$, $60^{\circ}$, $72^{\circ}$ showed a significant increase in the ABDF group after intervention, with a more significant improvement in EO and TrA muscle thickness in the ABDF group compared with the AB group (p<0.05). Also, the strength at $48^{\circ}$ strength showed a significant improvement in the ABDF group than the AB group (p<0.05). Conclusions: The study results showed that abdominal muscle contraction exercises with AD in patients with LBP had an influence on abdominal muscle thickness and strength. Therefore, these findings suggest that ABDF may be useful approach for enhancement of abdominal muscle thickness and strength in patients with chronic low back pain.

• Physical Therapy Korea
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• v.26 no.1
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• pp.51-59
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• 2019

Background: Chronic low back pain (CLBP) causes morphological changes in muscles, reduces muscle strength, endurance and flexibility, negatively affects lumbar stability, and limits functional activity. Plank exercise strengthens core muscles, activates abdominal muscles, and improves intra-abdominal pressure to stabilize the trunk in patients with CLBP. Objects: We investigated the effect of plank exercise on abdominal muscle thickness and disability in patients with CLBP. Methods: We classified 33 subjects into 2 groups: An experimental (n1=17) and a control group (n2=16). Patients in the experimental group participated in plank exercise and those in the control group participated in stretching exercise. Patients in both groups attended 20-minute exercise sessions thrice a week for 4 weeks. Abdominal muscle thickness in each subject was evaluated ultrasonographically, and disabilities were assessed using the Oswestry disability index (ODI). Results: Four weeks later, abdominal muscle thickness showed a significant increase over baseline values in both groups (p<.05). Patients in the experimental group reported a more significant increase in the thickness of the external oblique muscle than that in the control group (p<.05). ODI scores in the experimental group were significantly lower after intervention than before intervention (p<.05). Conclusion: Plank exercise increases the thickness of the external oblique muscle and reduces disability secondary to mild CLBP. Therefore, plank exercise is needed to improve lumbar stability and functional activity in patients with mild CLBP.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.15 no.1
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• pp.46-52
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• 2019

This work proposes a noncontact ultrasonic transducer for detecting wall-thinning of containment liner plates of nuclear power plants by measuring their thickness without physical contact. Because the containment liner plate is designed to prevent atmospheric leakage of radioactive substances under severe nuclear accident, its wall-thinning inspection is important for safety of nuclear power plants. Wall-thinning investigation of containment liner plates have been carried out by measuring their thickness with contact-type ultrasonic thickness gauge by inspectors and needs a lot of time and cost. As an alternative, an electromagnetic acoustic transducer measuring precisely thickness of containment liner plates without any physical contact or couplant was suggested in this research. A transducer generating and measuring shear ultrasonic waves in thickness direction was designed and wave field produced by the transducer was analyzed to verify the design. The working performance of the suggested transducer was tested with carbon steel plate specimens with various thicknesses. The test result shows that the proposed transducer can measure thickness of the specimens precisely without any couplant and implies that swift scanning of wall-thinning of containment liner plates will be possible with the proposed transducer.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.755-758
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• 2014

This paper has analyzed the change of threshold voltage for oxide structure of symmetric and asymmetric double gate(DG) MOSFET. The asymmetric DGMOSFET can be fabricated with different top and bottom gate oxide thickness, while the symmetric DGMOSFET has the same top and bottom gate oxide thickness. Therefore optimum threshold voltage is considered for top and bottom gate oxide thickness of asymmetric DGMOSFET, compared with the threshold voltage of symmetric DGMOSFET. To obtain the threshold voltage, the analytical potential distribution is derived from Possion's equation, and Gaussian distribution function is used as doping profile. We investigate for bottom gate voltage, channel length and thickness, and doping concentration how top and bottom gate oxide thickness influences on threshold voltage using this threshold voltage model. As a result, threshold voltage is greatly changed for oxide thickness, and we know the changing trend very differs with bottom gate voltage, channel length and thickness, and doping concentration.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.4
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• pp.183-190
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• 2021

Purpose : The purpose of this study was to investigate the effect of side planks on the muscle thickness of the core muscles, external oblique, internal oblique, and transverse abdominis, and this study was conducted to compare whether side plank exercise according to the application of various unstable support surfaces increases the thickness by activating the action of the muscles. Methods : The subjects of this study were 30 healthy adults and were randomly and equally assigned to three groups by a random number table. All subjects were divided into three groups according to the application of an unstable support surface during the side plank(Group A = stable support, Group B = one unstable support, Group C = two unstable supports). The side plank exercise was performed 30 minutes a day, 3 times a week for a total of 4 weeks. The muscle thickness of the core muscle was measured before the intervention, 2 weeks, 4 weeks, and 3 times in total. All measured data were comparatively analyzed by repeated measures ANOVA and one-way ANOVA. The statistical significance level was set to .05. Results : The results of this study were as follows : 1. All muscles showed an interaction between training period and group. 2. There was a significant difference between the groups at the 2 weeks and 4 weeks of the internal oblique and transverse abdominis muscle measurements. Conclusion : The thickness of the abdominal muscle increased during the side plank exercise according to the support surface, and the thickness of the abdominal muscle increased the most during the side plank exercise on the unstable support surface. Therefore, it is thought that the addition of an unstable support surface will provide a more effective therapeutic effect on the thickness change of the abdominal muscle during side plank exercise.

• Current Photovoltaic Research
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• v.9 no.3
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• pp.84-95
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• 2021

The power conversion efficiency of Cu₂ZnSnSe₄ (CZTSe) solar cells depends on the absorber layer thickness; however, changes in the characteristics of the cells with varying absorber layer thickness are unclear. In this study, we investigated the changes in the characteristics of CZTSe solar cells for varying absorber layer thickness. Five absorber thicknesses were employed: CZTSe1 2.78 ㎛, CZTSe2 1.01 ㎛, CZTSe3 0.55 ㎛, CZTSe4 0.29 ㎛, and CZTSe5 0.15-0.23 ㎛. The efficiency of the CZTSe solar cells decreased as the absorber thickness decreased, resulting in power conversion efficiencies of 10.45% (CZTSe1), 8.67% (CZTSe2), 7.14% (CZTSe3), 3.44% (CZTSe4), and 1.54% (CZTSe5). As the thickness of the CZTSe absorber layer decreased, the electron-hole recombination at the grain boundaries and the absorber-back-contact interface increased. This caused an increase in the current loss, owing to light loss in the long-wavelength region. In addition, as the thickness of the CZTSe absorber layer decreased, more ZnSe was produced, and the resulting defects and defect clusters led to an open-circuit voltage loss.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.1
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• pp.41-51
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• 2018

In case of evaluating the bond stress of a void deck plate using a wire steel, there is no standard formula considering both the influence on the void and the type of the reinforcing bar. Therefore we proposed a model equation considered the bond characteristics of the void deck plate. A total of 46 specimens was carried out a direct pull-out test and the test variables were the presence of a void body, type of reinforcing bar, the inner cover thickness according to the location of reinforcing bars and bond region. As a result of the comparison between the steel bar and steel wire, the bond stress of the steel wire with the relative rib area of 0.071 is 4.5 ~ 28.58% lower than that of the steel bar with 0.092 and the bond stress reduction rate increases when the inner cover thickness is insufficient. In the case of the inner cover thickness of $1.7d_b$ and $2.7d_b$, the bond stress was reduced to 48.7 ~ 68.4%. In the inner cover thickness was $4.9d_b$ and $5.2d_b$, the bond stresses were equivalent to those of the solid specimens. It was confirmed that the average bond stress and strain were affected by the inner cover thickness. Therefore the predicted model for one module of the void deck plate is proposed and verified by considering the bond characteristics of the void deck plate.

• PNF and Movement
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• v.12 no.4
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• pp.243-248
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• 2014

Purpose: The transverse abdominis and themultifidus muscle are located in the core. They surround one's trunk and help in body stabilization. Specifically, they control spine articulation to maintain posture and balance. Therefore, weakened deep muscle in the trunk may cause spinal malalignment. This study aims to compare the correlation between the thickness of the transverse abdominis and the multifidus muscle and the spine alignment among college students in their 20s. Methods: This study measured the thickness of the transverse abdominis and the multifidus muscle of 42 healthy college students in their 20s using ultrasonic waves. The thickness of the muscle was measured for the length of the cross-section except for fascia. The thickness of the left and right muscles was measured, and the mean value was calculated. As the thickness of the transverse abdominis can increase because of pressure during exhalation, it was measured at the last moment of exhalation. Spinal alignment was measured by the kyphosis angle, lordosis angle, pelvic tilt, trunk inclination, lateral deviation, trunk imbalance, and surface rotation using Formetric III, which is a three-dimensional imaging equipment. They were measured for three times, and the mean values were calculated. The general characteristics of the subjects were analyzed using descriptive statistics. The correlations between each factor were analyzed using Pearson's correlation analysis. Results: The transverse abdominis showed asignificant correlation with trunk inclination (p<.05). The multifidus muscle showed a significant positive correlation with pelvic tilt and a negative correlation with surface rotation (p<.05). Conclusion: The thickness of transverse abdominis and the multifidus muscle appears to influence spinal alignment. Specifically, the multifidus muscle, which plays an important role on the sagittal plane, influences surface rotation, thus making it an important muscle for scoliosis patients. Therefore, a strengthening training program for the transverse abdominis and the multifidus muscle is necessary according to specific purposes among adults with spinal malalignment.

• PNF and Movement
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• v.18 no.3
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• pp.333-341
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• 2020

Purpose: The purpose of this study was to investigate the effect of open and closed kinetic chain exercises with a sling on neck flexor thickness during chin-in movement in office workers with forward head posture. Methods: Thirty-one selected subjects randomly performed chin-in movement in open kinetic chain and closed kinetic chain exercises using a sling. All subjects were measured for their neck flexor thickness using ultrasound measurement equipment during the performance of chin-in movement in open and closed kinetic chain exercised. A paired t-test was used to compare the thickness of the total neck flexor, superficial, and deep neck flexor, respectively, between open and closed kinetic chain exercises with chin-in movement. Results: The thickness of the superficial neck flexor diminished in size more greatly during the chin-in movement with the closed kinetic chain than the open kinetic chain, but this was not a statistically significant difference (p > 0.05). On the other hand, the thickness of the total neck flexor and deep neck flexor had more greatly increased during the chin-in movement with the closed kinetic chain than the open kinetic chain, and this was a statistically significant differences (p < 0.05). Conclusion: This study suggested that chin-in movement with a closed kinetic chain is more effective in activating the deep neck flexor than the open kinetic chain. Thus, we believe that the closed kinetic chain exercise using a sling is an effective intervention to correct the postural alignment of individuals with forward head posture.