• Steel and Composite Structures
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• v.30 no.2
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• pp.109-121
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• 2019

This paper presents the second part of the modeling for the strap combined footings, this part shows a mathematical model for design of strap combined footings subject to axial load and moments in two directions to each column considering the soil real pressure acting on the contact surface of the footing for one and/or two property lines of sides opposite restricted, the pressure is presented in terms of an axial load, moment around the axis "X" and moment around the axis "Y" to each column, and the methodology is developed using the principle that the derived of the moment is the shear force. The first part shows the optimal contact surface for the strap combined footings to obtain the most economical dimensioning on the soil (optimal area). The classic model considers an axial load and a moment around the axis "X" (transverse axis) applied to each column, i.e., the resultant force from the applied loads is located on the axis "Y" (longitudinal axis), and its position must match with the geometric center of the footing, and when the axial load and moments in two directions are presented, the maximum pressure and uniform applied throughout the contact surface of the footing is considered the same. A numerical example is presented to obtain the design of strap combined footings subject to an axial load and moments in two directions applied to each column. The mathematical approach suggested in this paper produces results that have a tangible accuracy for all problems and it can also be used for rectangular and T-shaped combined footings.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.711-717
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• 2017

The railway is a public transportation system that provides large-scale passenger transportation and service, whose reliability and safety is the top priority. The wiring of railway vehicles is classified into train control lines (train lines) and communication lines. The train lines are used for input / output signals related to vehicle driving and safety functions, and the communication lines are used for the input / output signals for passenger services such as broadcasting. In order to measure the reliability of railway vehicles, a train line is applied to the input / output interface of the control signals between the electric control devices in the vehicle, and there are many electromechanical devices such as relays and contactors for the control logic. In fact, since the vehicle control circuit is composed of several thousand contacts, it is difficult to check for errors such as contact failure, and it is impossible to check the real-time status, so a lot of manpower and time is required for regular maintenance. Therefore, we analyze the current state of the train line design of the electric equipment used for driving and services in domestic railway cars and propose three wiring reduction methods to improve it. Based on the analysis of domestic electric vehicles, it was confirmed that the wiring reduction effect is 35% or more.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.41-57
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• 2001

It is well known that the apposition of bone at implant surface would be influenced by the microstructure of titanium implants. The purpose of this study was to compare bone healing around the screw-shaped titanium implant with three different surface topographies in the canine mandibles by histological and biomechanical evaluation. All mandibular premolars of six mongrel dogs were extracted and implants were placed one month later. The pure titanium implants had different surface topographies: smooth and machined ($Steri-OSS^{(R)}$: Group II); sandblasted and acid-etched ($ITI^{(R)}$, SLA: Group III) surface. The fluorescent dyes were injected on the 2nd (calcein), 4th (oxytetracycline HCI) and 12th (alizarin red) weeks of healing. Dogs were sacrificed at 4 and 12 weeks after implantation. The decalcified and undecalcified specimens were prepared for histological and histo-metrical evaluation of implant-bone contact. Some specimens at 12 weeks after implantation were used for removal torque testing. Histologically, direct bone apposition to implant surface was found in all of the treated groups. More mature and dense bone was observed at the implant-bone interface at 12 weeks than that at 4 weeks after implantation. Under the fluorescent microscope, thick regular green fluorescent lines which mean early bone apposition were observed at the implant-bone interface in Group III, while yellow and red fluorescent areas were found at the implant-bone interface in Group I and II. The average implant-bone contact ratios at 4 weeks of healing were 54.3% in Group I, 57.7% in Group II and 66.2% in Group III. In Group I, implant-bone contact ratio was significantly lower than Group II and III(p<0.05). The average implant-to-bone contact ratios at 12 weeks after implantation were 64.3% in Group I, 66.7% in Group II and 71.2% in Group III. There was no significant difference among the three groups. In Group I and II, the implant-bone contact ratio at 12 weeks increased significantly in comparison to ratio at 4 weeks(p<0.05). The removal torque values at 12 weeks after implantation were 90.9 Ncm in Group I, 81.6 Ncm in Group II and 77.1 Ncm in Group III, which were significantly different(p<0.05). These results suggest that bone healing begin earlier and be better around the surface-treated implants compared to the smooth surface implants. The sandblasted and acid-etched implants showed the most favorable bone response among the three groups during the early healing stage and could reduce the waiting period prior to implant loading.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.05a
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• pp.155-159
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• 2007

We conduct intelligent simulation of three-dimensional forging processes in this paper. A new remeshing technique is employed for this purpose. Not only the state variables including strain and strain-rate but also the geometrical features including die-material contact conditions and the characteristic lines or surfaces are taken into account during remeshing. The presented approach is applied to the Baden-Baden benchmark test example and its influence on the simulated results is discussed particularly in terms of the deformed shape with emphasis on the characteristic line.

• IMMUNE NETWORK
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• v.12 no.5
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• pp.217-221
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• 2012

Fibroblast-like synoviocytes (FLS) colocalize with leukocyte infiltrates in rheumatoid synovia. Proinflammatory leukocytes are known to amplify inflammation by signaling to FLS, but crosstalk between FLS and regulatory T cells (Tregs) remains uncharacterized. To address this possibility, we cocultured FLS lines derived from arthritic mice with Tregs. FLS that expressed the ligand for glucocorticoid-induced TNF receptor family-related gene (GITR) decreased expression of Foxp3 and GITR in Tregs in a contact-dependent manner. This effect was abolished by blocking antibody to GITR. On the other hand, the Tregs caused the FLS to increase IL-6 production. These results demonstrate that inflamed FLS license Tregs to downregulate Foxp3 expression via the GITRL/GITR interaction while the Tregs induce the FLS to increase their production of IL-6. Our findings suggest that the interaction between FLS and Tregs dampens the anti-inflammatory activity of Tregs and amplifies the proinflammatory activity of FLS, thereby exacerbating inflammatory arthritis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1525_1526
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• 2009

In this paper, we have studied the bulging phenomenon of ink-jet printed silver lines. The used silver inks are DGP-40LT-15C and DGH-55HTG of Advanced Nano Product (ANP) Company. We investigated the behavior of bulging by changing the polarity of the inks, the surface energy of substrate and droplet spacing in printing. The contact angle of the polar inks increased much more sensitively than the nonpolar ink as the surface energy of the substrate increases. In the case of the nonpolar ink, the bulging phenomenon occurred seriously as the droplet spacing decreased at the constant surface energy.

• Structural Engineering and Mechanics
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• v.53 no.3
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• pp.429-442
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• 2015

The measurement from the indentation process depends on the amount of pile-up or sink-in around the contact impressions. In this paper, finite element concept is utilized to study the pile-up and sink-in behaviour for the wide range of materials with different young's modulus, yield stresses, strain-hardening exponents and coefficient of friction values. The exact indentation model is created by using the two dimensional axisymmetrical model for simulating the spherical indentation process on the lines of Taljat and Pharr (2004) work. The result shows that during spherical indentation process the amount of pile-up is greatly influenced by the strain hardening exponents in addition to other material properties and depth of penetration. The numerical results from the finite element analysis are also validated using the exact multilinear material properties obtained from the tensile testing for the materials like mild steel, brass and aluminium.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.481-484
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• 2008

In order to reduce IR drop through common electrode in AMOLED, we propose a novel method to form electrical contact between highly-conductive bus lines and common electrode by using a plasma-assisted patterning of OLED layers and double deposition of the common electrode. Plasma-assisted patterning effects on OLED performance and degradation have been investigated. This patterning method caused turn-on voltage decrease, current flow increase at the same applied OLED voltages, quantum efficiency decrease, and rapid degradation at early stage during the lifetime test. However, comparable 70% luminance lifetime were obtained for both patterned and non-patterned OLEDs.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.447-450
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• 2002

Recently polymeric insulators and arresters are being used for outdoor high voltage applications. Polymeric insulators for transmission line have significant advantages over porcelain and glass insulators, especially for ultra-high voltage(UHV) transmission lines. Their advantages are light weight, vandalism resistance and hydrophobicity. Polymeric insulator kind are a relatively new technology, but their expected life is still unknown. In this paper, the material property for polymeric insulating material such as silicone rubber and EPBM is investigated by cross-link time and the relation between tracking resistance and W resistance is analyzed by IEC 60587 and W aging experiment.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.139.1-146
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• 2001

Contact lines are necessary to supply electric locomotives with electric power. As most railways are gradually electrified with modernized electric cars, the demand for catenary wires and their facilities are also increased. Catenary wires made by metallic materials are generally used in the open air. They are exposed to the marine area with air-borne salt or severely polluted industrial area with much corrosive emission gases depending on the railway locations. In urban area, acid rain may cause a degradation of catenary wire system. Corrosion of catenary wires can make their actual lifetime shorter than that originally designed. Thus, the messenger wires, a kind of catenary wire system, were investigated with respect to corrosion, which include new and the used one collected at the field. They are also vibrated with some amplitude everytime the train passes through the railway. The frequent cyclic load on the wire any result in a fatigue damage, Surface damage by corrosion can make fatigue crack initiate with ease. In the present study, the fatigue life of the used wire was measured 40 to 50% shorter than that of new one in average.