• 대한건축학회논문집:구조계
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• 제34권4호
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• pp.15-23
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• 2018

The purpose of this study is to evaluate the anchorage capacity of longitudinal bars for reinforced concrete exterior beam - column joints with steel fiber volume fractions. For this purpose, the steel fiber volume fraction was set to 0, 1, 2%, and the performance was compared with that of each other specimens. According to the test results, the maximum strength of EX-HK-NJR-0 decreased by 13% compared with the control specimen and EX-HK-NJR-1 decreased by 3% compared to the control specimen. However, when 2% of steel fiber was mixed, the maximum strength increased about 56% compared to the control specimen. The energy dissipation capacity of EX-HK-NJR-0 (when no transverse steel bars are placed) decreased by 61% compared to the control specimen. In addition, the energy dissipation capacity of the specimens with a steel fiber content of 1% decreased by 5% and 2% increased by 94% compared to control specimen. EX-HK-NJR-1,2 and the control specimen EX-HK-JR-0 experienced yielding of the reinforcing bars at the column interface before maximum strength development. However, when the EX-HK-NJR-0, the reinforcing bars at the column interface experienced yielding after maximum strength development. Therefore, reinforcement of steel fiber is considered to reduce the required development length for yielding of steel bars.

• Computers and Concrete
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• 제29권2호
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• pp.81-92
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• 2022

The influence of normal stress perpendicular to the potential shear plane was always neglected in existing researches, which may lead to a serious deviation of the shear strength of concrete members in practice designs and numerical analyses. In this study, a series of experimental studies are carried out in this paper, which serves to investigate the shear behavior of concrete under compression shear loading. Based on the test results, a three-phase shear failure model for cohesive elements are developed, which is able to take into consideration the influence of normal stress on the shear strength of concrete. To identify the accuracy and applicability of the proposed model, numerical models of a double-noted concrete plate are developed and compared with experimental results. Results show that the proposed constitutive model is able to take into consideration the influence of normal stress on the shear strength of concrete materials, and is effective and accurate for describing the complex fracture of concrete, especially the failure modes under compression shear loadings.

• The Journal of Korean Physical Therapy
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• 제29권4호
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• pp.187-193
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• 2017

Purpose: The purpose of this study was to confirm the immediate effect of wrist joint mobilization with taping on the range of motion, grip strength, and spasticity. Methods: Thirty stroke patients were randomly divided into two groups: the joint mobilization with taping group (n=15) and a taping group (n=15). For measurement of spasticity and joint range of motion, the modified Tardieu scale, active and passive range of motion of wrist flexion, as well as extension were measured by the Rapael smart glove, and for grip strength measurement, grip dynamometer was performed. Results: The experimental group showed a significant improvement in the range of motion, grip strength, and spasticity after 10 minutes of taping (p<0.05), no significant difference was found in the control group (p>0.05). However, there was no significant difference between the two groups (p>0.05). Conclusion: The study found that wrist joint mobilization with taping has an immediate effect on wrist range of motion, grip strength, and spasticity in stroke patients, whereas it was not effective in the control group with just taping. The long-term change still needs to be evaluated, when taking into consideration of the carryover effect.

• 한국농공학회논문집
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• 제58권2호
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• pp.83-90
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• 2016

This study was performed to evaluate the effective analysis of flexural performance for polypropylene fiber (PF) reinforced EVA concrete that can be used in marine bridge, tunnel and agricultural structures under flexural load. The control design was applied in ready mixed concrete using 10 % fly ash of total binder weight used in batch plant. On the basis of the control mix design, there was designed mix types that contained PF ranged from 0 % to 0.5 % by volume ratio into two mix types of using 0 % and 5.0 % EVA contents of total binder weight. Before evaluating the flexural performance, we tested compressive strength and flexural strength to evaluate whether polypropylene fiber reinforced concrete could be used or not in site. The method of flexural performance evaluation was applied by ASTM C 1609. These results showed the maximum compressive strength and flexural strength was measured at each E5P1 and E5P2. Concrete reinforced with PF exhibited deflection-softening behavior. In the concrete reinforced with 0.4 % PF contents and containing 5.0 % EVA, the flexural performance was the best.

• 대한정형도수물리치료학회지
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• 제14권1호
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• pp.31-38
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• 2008

Purpose : The purpose of this study was to compare the effectiveness of both neuromuscular electrical stimulation(NMES) and isometrical exercise(IE) to strengthen the quadriceps femoris muscle. The relationships between the strength changes and the relative force and duration of training contractions were also studied. Methods : The subjects were divided into three group. The control group(n=6) received no exercise and/or stimulation. The isometric exercise (IE) group(n=6) performed maximum isometric contractions, and the neuromuscular electrical stimulation(NMES)(n=6) engaged electrically stimulated isometric contractions, three days a week for four weeks. Results : Results showed that both IE group and NMES group were found to have an increase in strength significantly greater(p<0.05) than the control group at 4 week. But between IE group and NMES group were not found to have an difference in strength significantly. Conclusion : The relative increase in isometric strength, using IE and NMES, may be determined by the ability of the subjects to tolerate longer and more forceful contractions. Suggestions for further research and implications for the clinical of IE and NMES for strength-training are discussed.

• 한방재활의학과학회지
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• 제21권4호
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• pp.219-226
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• 2011

Objectives: The aim of this pilot study is to investigate qigong as a trailing method to treat diseases and improve the quality of life. Methods: We used a controlled clinical study in this research qigong group(n=34) practiced the zhan zhuang gong for 2 minutes. Control group(n=33) did low intensity walking for 2 minutes. Changes of grip strength, heat rate and rating of perceieved exertion were measured before and after treatment. Paired t-tests and independent t-tests were applied for statistical analysis. Results: Qigong group showed significant improvement in grip strength(p<0.05), whereas the control group showed insignificant changes(p<0.05). Both groups demonstrate significant changes in heart rate(p<0.05). In rating of perceieved exertion, significant difference showed between groups(p<0.05). Conclusions: The zhan zhuang gong, a kind of qigong improved grip strength by 2 minutes of practice. We may conclude that zhan zhuang gong could be a method of improving physical strength.

• Physical Therapy Rehabilitation Science
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• 제10권3호
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• pp.263-269
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• 2021

Objective: The purpose of this study was to examine the effects lumbar stabilization exercise with kinesio taping on pain, muscle strength, and oswestry disability index (ODI) in patients with chronic low back pain. Design: Two groups pre-post randomized controlled design Methods: Thirty-two subjects were randomly divided in two groups; 1) lumbar stabilization exercise with kinesio taping group (Experimental group, n=16), 2) lumbar stabilization exercise with sham kinesio taping group (Control group, n=16). The intervention was conducted in each group for thirty minutes a day, 5 times a week, for 4 weeks. Both group did 30 minutes of lumbar stabilization application. Evaluations were performed before the commencement of training and again 4 weeks after training was initiated. Visual analog scale (VAS) was used to evaluate pain level of patients with chronic low back pain. Distal muscle test was used to evaluate muscle strength of trunk extension. In addition, ODI was used to evaluate activity daily life of low back pain. Results: After training, the VAS, muscle strength of trunk extension and ODI were significantly more improvement in Experimental group than in the control group (p<0.05). Conclusions: We confirmed that the effects of lumbar stabilization exercise with kinesio taping group on pain, muscle strength, and ODI in patients with chronic low back pain.

• Physical Therapy Rehabilitation Science
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• 제10권4호
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• pp.414-420
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• 2021

Objective: The purpose of this study was to investigate the effects of coordinative locomotor training(CLT) using elastic bands on dynamic balance and grip strength for Elementary school baseball players and to provide correct posture guidance and reference on the prevention and rehabilitation program of sports damage and injury in the future. Design: Two groups pre-post randomized controlled design. Methods: Forty-six subjects were randomly divided in two groups;1) CLT using Elastic Band group(Experimental group, n=23), 2) Routine baseball training group(Control group, n=23). The intervention was conducted total 16 times for sixty minutes a day, 2 times a week, for 8 weeks. Evaluations of dynamic balance ability and grip strength were performed with all subjects before the commencement of training and 8 weeks after training. Results: Compared to the control group after training, the dynamic balance ability and dominant handgrip strength of the experimental group were significantly more improved(p<0.05). Conclusions: We confirmed that the effects of CLT using elastic bands on dynamic balance ability and grip strength in Elementary school baseball player. This study should be used for improving the quality of the Elementary school baseball player's training and would be contributed prevention and rehabilitation program of sports damage and injury.

• Journal of Welding and Joining
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• 제34권6호
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• pp.69-74
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• 2016

Because the pure titanium has superior corrosion resistance and formability compared with different material, it is widely used as material of welded heat exchanger. When the welding of heat exchanger is carried out, certain area in which welding start and end are overlapped occurs. The humping of back bead is formed in the overlap area due to partial penetration. Thus in this study, the experiments were carried out by changing the length and wave shape of overlap area, and then the weldabiliay was evaluated through the observation of microstructure, the measurement of hardness and tensile-shear strength test in the overlap area. When overlap length was 9.8mm, humping bead was suppressed. The microstructure of overlap area coarsened and its hardness increased due to remelting. As a result of tensile-shear strength test in the overlap area according to applying the wave shape control, it was confirmed that the overlap area applied wave shape control had more excellent yield strength and ductility.

• 치위생과학회지
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• 제23권4호
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• pp.389-395
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• 2023

Background: Dental caries prevention is a key research focus in dentistry, requiring advancements in the formulation of dental sealants. This study investigated the physical and antibacterial attributes of dental sealant enriched with phytoncide. Methods: Phytoncide was mixed with a commercially available dental sealant (Clinpro) at concentrations of 0 (control), 1.5%, 3%, and 4.5% by weight (wt%). The flexural strength, curing depth, and wettability of the dental sealant were measured. Antibacterial properties against Streptococcus mutans were evaluated through the enumeration of colony-forming units. Statistical analyses employed one-way variance analysis followed by Tukey's test (p<0.05). Results: The dental sealant containing 3% phytoncide showed no significant difference in flexural strength and curing depth compared with that in the control group (p>0.05). The flexural strength and curing depth decreased with increasing phytoncide content and significantly differed in sealant containing 4.5 wt% phytoncide (p<0.05). Wettability did not differ between the experimental and control groups (p>0.05). The antibacterial properties of the sealant containing 1.5% phytoncide were the same as those of the control group (p>0.05). The bacterial viability was significantly reduced in groups containing 3% and 4.5% phytoncide compared with that in the control group (p<0.05). Conclusion: Dental sealants incorporating phytoncide have a promising potential as antibacterial dental materials.