• Journal of the Korea Institute of Building Construction
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• v.8 no.5
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• pp.43-51
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• 2008

This study examines shear capacity performance and structural characteristics of reinforced concrete beam using carbon fiber sheet(CFS), g)ass fiber sheet(GFS), glass fiber steel plate(GSP) and carbon fiber bar CB) which are reinforcing materials for reinforced concrete beam in order to produce similar condition to repair and reinforce actual structure and aims to provide data available In designing and constructing reinforced concrete structures under the structural damage. This study obtains the following conclusions. After considering the shear experiment results. it was indicated that the CB reinforced test object was the best in the shear capacity improvement and ductility capacity as it was contained in the concrete and was all operated, Also, GFS reinforced test object indicated the reduced flexural capacity but good shear capacity. GSP reinforced test object had bigger reinforcing strength than other reinforcing test objects. On the other hand, it showed the lowest reinforcement effect as compared section thickness of reinforced material because it showed the bigger relativity a section thickness of reinforced material. If the adherence to the concrete is improved, it will seem to show bigger reinforcement effect.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.221-222
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• 2017

An analysis of the current water leak status of understand structure (underground parking lots, staircases, plumbing systems, water reservoirs, etc.) of multi-family housing in South Korea shows that water leaks are found from cracks in all areas of the underground structure caused by the degradation environment (water pressure by underground water, humidity, temperature, earth pressure, soil behaviour and vibration, etc.), which result in various problems, including mold, malodour, debonding of finishing materials, exfoliation, breakout, water leaks in electrical boxes, efflorescence, sedimentation of calcium hydroxide, decoloration, rusting, damages and pollution among others. Therefore, this study aims to analyse the current status of water leaks in underground structure and use the results as the basic data for developing a standard guideline for water leaks and maintenance by parts of the underground structure of multi-family housing.

• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.3
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• pp.181-189
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• 2001

Recently, the need for strengthening reinforced concrete(R.C.) structure has been increased, particularly when there is an increase in load requirements, a change in use, a degradation problem, or design/construction defects. The use of composite materials for structural repair presents several advantages and has been investigated all over the world. It is well known that the incorporation of carbon fiber sheet(CFS) with concrete is one of the most effective ways to strengthen the R.C. structure. In this papers, experimentally investigated the ductile behavior of the R.C. beams strengthened with CFS, and provided the basic data for design of R.C. beams strengthened with CFS. Tests were carried out with 15 beams ($20cm{\times}30cm{\times}240cm$) reinforced with CFS, and with parameters including and the ratio of tensile reinforcement to that of balanced condition and number of CFS. The results show that strengthened and non-strengthened beams exhibit different ductile behovior. Non-strengthened beams showed increase of ductility as amount of the tensile reinforcement decreased. However, bearing capacity of the CFS-strengthened beams are dictated by the strength of the CFS layers that a very high ductility is indicated for the beams with large number of CFS.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.80-83
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• 2009

Purpose: A triple labral lesion represents a combination of injuries of the anterior, posterior and superior glenoid labrum. The injury mechanism and symptoms is not completely understood. Materials and Methods: We encountered a triple labral injury in a 39-year-old male complaining pain and active abduction difficulty after a motor vehicle accident. Currently, he does not complain any instability symptoms. The labrum was repaired using bio-absorbable suture anchors and a suture hook. Results: Eighteen months following surgery, the active range of motion was restored and he had no difficulty in his daily activities.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.76-79
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• 2009

Purpose: Capsulolabral reconstruction in a traumatic anterior instability of the glenohumeral joint is successful not only for the prevention of recurrent instability but also for the restoration of function. Materials and Methods: However, a capsulolabral procedure alone cannot guarantee a successful result when there is severe bone loss of the glenoid. Results: We report the surgical technique and results of capsulolabral repair and extraarticular bone block with an autogenous iliac crest graft performed on three cases (all male, average age 28 years, minimum follow-up 12 months) with traumatic anterior instability associated with more than 30% glenoid bone loss.

• Restorative Dentistry and Endodontics
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• v.18 no.1
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• pp.95-102
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• 1993

Two functions of root canal medicaments and irrigants are to reduce microorganisms and to encourge the repair of apical tissues. The biocompatibility of endodontic materials has been tested using in vitro cell culture techniques. The purpose of this study Was to evaluate and compare the cytotoxic effects of 2 root canal irrigation solutions and 4 antiseptics on HEp-2 and McCoy cells. Two irrigation solutions were sodium hypochlorite. $H_2O_2$ and 4 antiseptics were povidone, ethanol, glutaraldehyde and benzalkonium chloride. Each solutions were serially diluted to 1:1, 1:10, 1:$10^2$, 1:$10^3$, 1:$10^4$, 1:$10^5$, 1:$10^6$. And each diluted solutions were added to the cells and cytotoxic effects were measured with the absorbance of formazan formed cells by ELISA READER. The results were as follows : 1. Benzalkonium chloride was the most cytotoxic on HEp-2 cell. (P<0.05) 2. $H_2O_2$ was the most cytotoxic on McCoy cell. (P<.05) 3. Povidone and ethanol showed mild cytotoxic effect on HEp-2 and McCoy cell. (P<0.05).

• Tribology and Lubricants
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• v.35 no.5
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• pp.317-322
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• 2019

In spite of progress in tribological research, machine component failure due to friction and wear has been reported frequently. This failure may lead to secondary damage that can cause huge expense for maintenance and repair. To prevent economic loss, it is important to detect and predict the initial failure point. In this sense, various researchers have been tried to develop Condition Monitoring (CM) method using Acoustic Emission (AE) generated while the materials undergo failure. In this study, effect of particles on friction and wear was investigated using the pin-on-plate friction test and AE signal was recorded with a band-width type AE sensor. The experiments were performed in dry and lubricant conditions using steel and glass as specimens. After the experiment, 3D laser microscope image was captured to evaluate the wear behavior quantitatively. The AE signal was analyzed in time-domain and frequency-domain. The amplitude was compared with the frictional results. The results of this study showed that particle generation accelerate wear, generate high magnitude AE signal and change the frequency characteristics of the signal. Also, lubricant condition test results showed low coefficient of friction, low wear rate, and low magnitude of AE signal compared to the dry condition. It is expected that the results of this study will aid in better assessment of wear in CM technology

• Journal of Conservation Science
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• v.35 no.1
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• pp.61-70
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• 2019

In this study, a scientific survey on the material of the mother-of-pearl floor mirror was conducted and conservation treatment processes were introduced. The survey results showed that the mother-of-pearl floor mirror in Daejojeon Hall of Changdeokgung is made of Dalbergia spp., and repair work seems to be done later with shorea spp. FT-IR analysis results showed that the varnishing is similar to the spectrum of lacquer. The metal wheels and metal line decorations set with mother-of-pearl were found to be made of brass based on XRF analysis, and the ingredient ratio showed that these were made in modern times. Foreign materials were stuck on the surface of the mother-of-pearl floor mirror before conservation treatment, which was in a structurally unstable condition owing to some missing submaterials. Conservation treatment was conducted on the damaged area to restore the mirror to its original appearance by using the same species of wood determined from the data obtained through the scientific survey.

• Transactions of Materials Processing
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• v.30 no.3
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• pp.109-118
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• 2021

Recently, there has been an increased interest in the remanufacturing of mechanical parts using metal additive manufacturing processes in regards to resource recycling and carbon neutrality. DED (directed energy deposition) process can create desired metallic shapes on both even and uneven substrate via line-by-line deposition. Hence, DED process is very useful for the repair, retrofit and remanufacturing of mechanical parts with irregular damages. The objective of the current paper is to investigate the effects DED process parameters, including the effects of power and the scan speed of the laser, on deposition and residual stress characteristics for remanufacturing of mechanical parts using experiments and finite element analyses (FEAs). AISI 1045 is used as the substrate material and the feeding powder. The characteristic dimensions of the bead shape and the heat affected zone (HAZ) for different deposition conditions are obtained from the experimental results. Efficiencies of the heat flux model for different deposition conditions are estimated by the comparison of the results of FEAs with those of experiments in terms of the width and the depth of HAZ. In addition, the influence of the process parameters on residual stress distributions in the vicinity of the deposited region is investigated using the results of FEAs. Finally, a suitable deposition condition is predicted in regards to the bead formation and the residual stress.

• Computers and Concrete
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• v.27 no.5
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• pp.395-406
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• 2021

This study experimentally and analytically investigates the shear behavior of corroded reinforced concrete (RC) beams repaired using steel fiber-reinforced concrete (SFRC) in the flexural zone. The experimental parameters are the corrosion degree (0%, 12%, and 17%) and the steel fiber volume in the SFRC (1.0%, 1.5%, and 2.0%). The test results reveal that corrosion degree significantly affects the shear resistance of the beams. The shear capacity of the beam with the corrosion degree of 17% was higher than that of the uncorroded beam, whereas the shear capacity of the beam with the corrosion degree of 12% was lower than that of the uncorroded beam. The shear efficiency of damaged beams can be recovered by repairing them using SFRC that contains a reasonable amount of steel fibers. In addition, two methods to estimate the shear capacity of the repaired beams are developed using the modified truss analogy and strut-and-tie models. The estimated shear capacity of the beam using the modified truss analogy model agrees well with the experimental data.