• Proceedings of the KSR Conference
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• 2003.10c
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• pp.493-499
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• 2003

Railroad, a superior mode of public transportation provides safe, efficient, speedy, comfortable and economical service, has fundamentally different characteristics from airplanes, ships and cars. Among the unique characteristics of a railroad is the fact that it operates on fixed track with multiple car trains. The subway system was first selected as the best solution to difficult automobile traffic conditions and environmental problems. Seoul subway no.1line (Jongno line) was opened for service on August 15, 1974. Seoul city has completed and now operates eight subway lines (286.7km) since 1974. At present the subways operate in Busan, Daegu and Incheon city, and are under construction in Gwangju and Daejeon city. The power source for subway trains has been electricity since 1896, and power supply systems are the third rail type and/or the catenary system. The typical catenary system is the rigid bar type. R-bar and T-bar are used in the rigid bar type of catenary system, and the two types of R-bar and T-bar are uesd in Korea also. R-bar is used only for AC 25kV power supply and T-bar for DC 1,500V. From 30 years of subway experience I would like to suggest the most economic catenary system to ensure of safety, reliability and expediency for the railway lines to be constructed and the forthcoming replacement due to the life cycle after studying and analysing the characteristics, advantages and disadvantages of R-bar and T-bar.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.223-231
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• 2011

The purpose of this case report is to introduce new attachment system(milled titanium bar with $Locator^{(R)}$ attachment) for implant supported overdenture in maxillary edentulous patients. A 56-years-old male patient visited the hospital due to the mobility of his maxillary fixed partial dentures(10-unit bridge). Including temporomandibular joint(TMJ), there was no specific PMHs to influence dental treatment. In radiographic and clinical evaluation, there was a severe bone resorption and mobility in maxillary teeth. Accordingly all the remaining maxillary teeth was extracted and fabrication of implant supported overdenture was planned. The milled titanium bar with $Locator^{(R)}$ was designed as an attachment system, considering the stability and retention of denture, masticatory efficiency, oral hygiene care, esthetics, pronunciation, and patient's financial state. The milled titanium bar was manufactured using CAD/CAM technology, and $Locator^{(R)}$ attachment connected to the bar by tap & drill method. For over 1-year, in terms of function and esthetics, satisfactory result was obtained.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.2
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• pp.453-458
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• 2017

R-Bar (Overhead Rigid Conductor system) has been lately used for the speed of over 200km/h in Europe, while it has been developed and used for the max. speed of 120km/h in Korea. Because R-Bar has advantages of reduction of tunnel cross sectional area and maintenance, its development for more high-speed is urgent in Korea having many mountain area. Therefore a sensitivity analysis of design parameters for the speed-up of R-Bar has performed in this study. For the analysis, we have developed a program for the prediction of dynamic characteristics between a pantograph and R-Bar. The program was evaluated with the actual test result and a current collection performance according to the parameters such as a distance between brackets, a stiffness of bracket and of R-Bar rail was predicted with the program.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1589-1590
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• 2015

전기철도차량에 전기를 공급하는 가공 전차선로 시스템은 커티너리(catenary) 방식과 강체가선 방식으로 구분 할 수 있으며 강체가선 방식은 DC 급전구간에서 주로 사용하고 있는 T-bar 시스템과 AC 급전구간에서 주로 사용하는 R-bar 시스템으로 구분 할 수 있다. 최근 국내환경에 적합한 고속용 R-bar 시스템의 개발을 진행하고 있으며 여기에 필요한 브래킷 지지 및 절연용 장간애자와 동상구분을 위한 절연구분장치 개발을 진행하고 있다. 따라서 국내에 수입하여 적용하고 있는 저속, 고속 R-bar 시스템용 장간애자 및 절연구분장치의 성능기준을 확인하고 개발에 필요한 성능기준을 검토 적용하여 고속 R-bar 시스템용 장간애자 및 절연구분장치 개발을 진행할 예정이다.

• The Journal of Advanced Prosthodontics
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• v.4 no.4
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• pp.254-258
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• 2012

Implant-supported overdenture is a reliable treatment option for the patients with edentulous mandible when they have difficulty in using complete dentures. Several options have been used for implant-supported overdenture attachments. Among these, bar attachment system has greater retention and better maintainability than others. SFI-Bar$^{(R)}$ is prefabricated and can be adjustable at chairside. Therefore, laboratory procedures such as soldering and welding are unnecessary, which leads to fewer errors and lower costs. A 67-year-old female patient presented, complaining of mobility of lower anterior teeth with old denture. She had been wearing complete denture in the maxilla and removable partial denture in the mandible with severe bone loss. After extracting the teeth, two implants were placed in front of mental foramen, and SFI-Bar$^{(R)}$ was connected. A tube bar was seated to two adapters through large ball joints and fixation screws, connecting each implant. The length of the tube bar was adjusted according to inter-implant distance. Then, a female part was attached to the bar beneath the new denture. This clinical report describes two-implant-supported overdenture using the SFI-Bar$^{(R)}$ system in a mandibular edentulous patient.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.1
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• pp.41-48
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• 2016

Edentulous patients with severe alveolar bone resorption have trouble with using traditional complete denture. In order to overcome these problems, implant-retained overdenture was developed. SFI-bar$^{(R)}$ system can save time and cost compared to other existing bar systems which need complicated laboratory procedures because it can be adjusted directly in a patient's mouth. A 55-year-old male, who had experienced a fractured lower old implant-retained overdenture, wanted a durable and painless denture. The fractured Locator$^{(R)}$ attachments were removed and edentulous mandible was restored with SFI-bar$^{(R)}$. A 77-year-old female with a medical history of the Parkinson's disease and severely absorbed alveolar bone of mandible, wanted to wear a retentive mandibular denture without pain. After placing two implants in front of mental foramen, two adaptors were connected to two implants and a tube bar was connected to the adaptors. A female part fitted to the bar was attached to the new denture. These clinical reports describe two-implant-retained overdenture using the SFI-bar$^{(R)}$ system in mandibular edentulous patients. Since the patients were satisfied esthetically and functionally during 2 years' observation, we would like to report cases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.458-463
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• 2010

MLCC (multi-layer ceramic capacitor) is usually fabricated by lamination of predetermined number of single layers. Often, the state of MLCC before sintering is called the green state, whose strength comes from the adhesion between the dielectric material and the polymer binder. Therefore the lamination of a single layer before sintering can be easily deformed by environment due to the relatively lower strength. After the compression process, which helps single sheets cohereto with adjacent sheets, the MLCC green bar is preheated to resolve the probable internal stress. Unfortunately, unexpected deformation after preheating resulted in problems during cutting of the MLCC green bar. In this study, one of 2 primary hypotheses which were proposed to resolve the unexpected deformation after preheating was examined by quantitative experiment with GC/MS (gas chromatograpy/mass spectrometer). The proportion of deformation caused by DOP evaporation, which was primarily evaporated componet during preheating, to the total deformation of the MLCC green bar was found to be 53%.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.207-214
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• 2015

Due to the limitations of conventional removable partial denture prostheses to treat a cleft lip & palate patient who shows scar tissue on upper lip, excessive absorption of the maxillary residual alveolar ridge, and class III malocclusion with narrow palate and undergrowth of the maxilla, 4 implants were placed on the maxillary edentulous region and a maxillary removable implant-supported partial denture was planned using a CAD/CAM milled titanium bar. Unlike metal or gold casting technique which has shrinkage after the molding, CAD/CAM milled titanium bar is highly-precise, economical and lightweight. In practice, however, it is very hard to obtain accurate friction-fit from the milled bar and reduction in retention can occur due to repetitive insertion and removal of the denture. Various auxiliary retention systems (e.g. $ERA^{(R)}$, $CEKA^{(R)}$, magnetics, $Locator^{(R)}$ attachment), in order to deal with these problems, can be used to obtain additional retention, cost-effectiveness and ease of replacement. Out of diverse auxiliary attachments, $Locator^{(R)}$ has characteristics that are dual retentive, minimal in vertical height and convenient of attachment replacement. Drill and tapping method is simple and the replacement of the metal female part of $Locator^{(R)}$ attachment is convenient. In this case, the $Locator^{(R)}$ attachment is connected to the milled titanium bar fabricated by CAD/CAM, using the drill and tapping technique. Afterward, screw holes were formed and 3 $Locator^{(R)}$ attachments were secured with 20 Ncm holding force for additional retention. Following this procedure, satisfactory results were obtained in terms of aesthetic facial form, masticatory function and denture retention, and I hereby report this case.

• Journal of the Korean Chemical Society
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• v.39 no.1
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• pp.1-6
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• 1995

The surface of a sapphire substrate used for hetero-epitaxy was chemically polished in a mixture of $H_3PO_4\;and\;H_2SO_4$ solution. The extent of etching for various crystal orientations was found to be dependent on the etching time at $315{\pm}2^{\circ}C$ and at the composition of $H_2SO_4 : H_3PO_4$=3 : 1. In addition, the etching rates of the substrates were investigated in the mixture of $H_2SO_4 : H_3PO_4$=3 : 1 by volume and in the temperature range of 280~320$^{\circ}C$. From the plot of log R against 1/T, the activation penergy ($(E_a)$) was found to be in the order of $({\bar1}012) > (10{\bar1}0) > (11{\bar2}0) > (0001)$ plane. After removing the surface layers of the sapphire with (0001), $({\bar1}012),\;(10{\bar1}0)\;and\;(11{\bar2}0)$ plane by a thickness of 64.6, 46.5, 16.2 and 5.1 ${\mu}m$, respectively, the morphology of the resulting surface was observed by SEM.

• Journal of Dental Rehabilitation and Applied Science
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• v.30 no.1
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• pp.64-70
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• 2014

The purpose of this case report is to introduce milled titanium bar with Locator$^{(R)}$ that made by CAD/CAM for implant supported overdenture in maxillary edentulous patients. For over 2 years, in terms of function and esthetics, satisfactory result was obtained.