• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.7
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• pp.185-197
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• 1996

We have adopted the strain compensated PBH(planar buried heterostructure) - LD in which the MQW active layer consisted of 1.4% compressively strained GainAsP (E$_{g}$ = 0.905eV) wells and 0.7% tensile strained GaInAsP(E$_{g}$ = 1.107eV) barriers grown by metal organic vapor phase epitaxy (MOVPE). We hav einvestigated effects of number of wells and the structure of the separate confinement heterostructure (SCH) layer in the strain-compensated MQW-PBH-LD. The threshold current, the external quantum efficiency, the transparency current density J$_{o}$, and the gain constant .beta. have been evaluated for uncoated MQW-PBH-LD. As the number of wells increases, the internal quantum efficiency and the transparency current density decreases, whereas the gain contant increases. The small width of the SCH layer shows the large internal quantum efficiency. The small internal loss and the large gain constant have been obtained by inserting the large bandgap SCH layer.

• Corrosion Science and Technology
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• v.16 no.3
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• pp.109-114
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• 2017

Monitoring of corrosion is in most cases based on simulation of environmental conditions on a large and complex structure such as a buried pipeline using a small probe, and the measurement of thermodynamics and kinetics of corrosion processes occurring on the probe surface. This paper presents a hybrid corrosion monitoring probe designed for simulating deteriorating conditions wrought by disbonded coatings and for measuring current densities and distribution of such densities on a simulated pipeline surface. The concept of the probe was experimentally evaluated using immersion tests under cathodic protection (CP) in high resistivity aqueous solution. Underneath the disbonded area, anodic currents and cathodic currents were carefully measured. Anodic current densities were used to calculate metal loss according to Faraday's law. Calculated corrosion patterns were compared with corrosion damage observed at the surface of the probe after a series of stringent tests. The capability of the probe to measure anodic current densities under CP, without requiring interruption, was demonstrated in high resistivity aqueous solution. The pattern of calculated metal loss correlated well with corrosion products distribution observed at the array surface. Working principles of the probe are explained in terms of electrochemistry.

• Journal of the Korean Institute of Rural Architecture
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• v.19 no.3
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• pp.17-24
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• 2017

The aim of this study is how to understand of structural and elemental landscape image in suburban village. Nowadays, it is well known fact that suburban villages are most likely to be invaded by urbanization. Therefore, the research is focused on how the image of suburb has been changed, what patterns have been created in residential area, what are the different outcomes from different distance, and what are the changes in types of buildings, at particular village called Doojeong in Pyeongtaek city. When collecting supplemental information, elders in village have been participated in comparison of traditional and foreign. The village shows significant characteristics of such phenomenon. According to the research, there are three results. First, ironically, the structural patterns of the village is concentric as seen on urban garden, yet they do not have central function. Second, traditional homes are transformed into functional shape. The most popular roof design that takes 65 percent of whole is modernized flat roof shape. Hanok (Korean traditional house) style is disappearing. Third, due to the massive barn buildings and their monochrome, the beauty of community and architectural harmony are buried.

• Archives of Plastic Surgery
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• v.33 no.4
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• pp.514-517
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• 2006

Purpose: To report a rare case of concealed penis that was aggravated by circumcision and simple way of treatment using skin flap. The concealed penis is a primarily pediatric disease and is usually treated by urologists. The plastic surgeons tend to see these patients when it become secondary deformation or in conjoinment with other specialties. In such situation, the plastic surgeons do not have many experiences. Methods: A 3-year-old boy was admitted with aggravated concealed penis after circumcision in congenital webbed penis. Patient had been operated with scar revision and skin flap and peri operative antibiotics. Results: The patient recovered well without any complication such as infection, hematoma and necrosis of flap. Patient was discharged POD#7 with remaining sutures. Patient was followed up for 7 months and he has no sign of erectile dysfunction, voiding dysfunction and evidence of inflammation of the urinary system. Conclusion: We experienced a case of concealed penis that was aggravated from aggressive circumcision in congenital webbed penis.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.464-465
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• 2008

Concrete poles(CP) are popular supports for distribution lines. Various types of grounding electrode, such as copper-clad rods, have been used to maintain CP's ground resistance under the required value. The buried part of CP can also have structural grounding effect because of its iron reinforcing rods inside CPs. In this paper, we measured the total ground current injected into CP ground while measuring the ground current splitting to the metal electrode as well as the total injecting current. By this, it was able to measure the ground current splitting to CP structure. Based on the measured results, interrelationship between ground resistance of metal electrodes and current split factor to CP structure was analyzed.

• Geomechanics and Engineering
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• v.14 no.3
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• pp.233-240
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• 2018

Pullout tests are usually employed to determine the ultimate bearing capacity of reinforced soil, and the load-displacement curve can be obtained easily. This paper presents an analytical solution for predicting the full-range mechanical behavior of a buried planar reinforcement subjected to pullout based on a bi-linear bond-slip model. The full-range behavior consists of three consecutive stages: elastic stage, elastic-plastic stage and debonding stage. For each stage, closed-form solutions for the load-displacement relationship, the interfacial slip distribution, the interfacial shear stress distribution and the axial stress distribution along the planar reinforcement were derived. The ultimate load and the effective bond length were also obtained. Then the analytical model was calibrated and validated against three pullout experimental tests. The predicted load-displacement curves as well as the internal displacement distribution are in closed agreement with test results. Moreover, a parametric study on the effect of anchorage length, reinforcement axial stiffness, interfacial shear stiffness and interfacial shear strength is also presented, providing insights into the pullout behaviour of planar reinforcements of MSE structures.

• Geomechanics and Engineering
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• v.23 no.4
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• pp.351-364
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• 2020

This paper numerically investigates the effects of a dip-slip fault (a normal or a reverse fault) movement on a segmental tunnel which transversely crosses either of this kind of faults. After calibration of the numerical model with results from literature of centrifuge physical tests, a parametric study is conducted to evaluate the effects of various parameters such as the granular soil properties, the fault dip angle, the segments thickness, and their connections stiffnesses on the tunnel performance. The results are presented and discussed in terms of the ground surface and tunnel displacements along the longitudinal axis for each case of faulting. The gradient of displacements and deformations of the tunnel cross section are also analyzed. It is shown that when the fault dip angle becomes greater, the tunnel and ground surface displacements are smaller, in the case of reverse faulting. For this type of fault offset, increasing the tunnel buried depth causes tunnel displacements as well as ground surface settlements to enhance which should be considered in the design.

• Archives of Plastic Surgery
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• v.47 no.4
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• pp.354-359
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• 2020

The medial sural artery perforator (MSAP) flap is a versatile fasciocutaneous flap that has been used successfully in the reconstruction of defects across the body. In specific cases, it may prove superior to more commonly used options (e.g., anterolateral thigh flap and radial forearm free flap). Historically, a disadvantage of the MSAP flap is the relatively small surface area it provides for reconstruction. We recently encountered a patient with extensive pelvic injuries from prior trauma resulting in significant scarring and contracture of the groin, tethering of the penis, and loss of the scrotum and one testicle. The patient was unable to achieve erection from tethering and his remaining testicle had been buried in the thigh. In considering the reconstructive options, he was not a suitable candidate for a thigh-based or forearm-based flap. An extended MSAP flap measuring 25 cm×10 cm was used for resurfacing of the groin and pelvis as well as for the formation of a neoscrotum. This report is the first to document an MSAP flap utilized for simultaneous groin resurfacing and scrotoplasty. Additionally, the dimensions of this flap make it the largest recorded MSAP flap to date.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.105-113
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• 2006

The footing of a bridge is a very essential part that support the whole load induced by the bridge itself and the traffic as well. However, once a bridge is built, the footing is buried under soil so the footing is invisible from outside. Therefore, the safety or condition of the footing is very difficult to estimate. Not only the length of the imbedded part of the footings but also the type of footings are unknown once the design record is gone. Some nondestructive techniques can be used to evaluate invisible part of the footings but the results have not been successful yet. Using GPR (Ground Penetrating Radar), which has been used for the nondestructive evaluation in military purposes, the condition assessment of the footings have been successfully conducted in this research. The field evaluation and laboratory tests have been conducted to find effective factors in the condition assessment of the footings. The equipment and basic theory of the GPR has been presented. The field test results show that the GPR can be successfully used for the safety evaluation of the footings. More test results and field data are needed for more precise evaluation of the footings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.2
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• pp.183-189
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• 2012

Most of the domestic residential buildings have used the traditional radiant heating system, circulating hot water through the cross-linked polyethylene(PE-X) pipe buried in the floor panel of the heating space. New type of the heating panel was recently developed using heat pipes with double wicks. Some experiments were carried out in this study to verify the thermal characteristics of this heating system at the unit heating space which surrounded by outer space whose temperature of air be maintained scheduled value with time. Through the various experiments with several parameters, such as flow rate, inlet and outlet temperatures of hot water and the heating duration and so on, we found that the floor heating system with heat pipes was able to reduce the pumping power for hot water circulation by 4~31% compared with the conventional panel heating system using PE-X pipe. These results could be used for optimal design and efficient operation of the heating system as well as improvement of thermal comfort.