• 한국압력기기공학회 논문집
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• 제14권1호
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• pp.58-65
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• 2018

The purpose of this study is to develop a Half Nozzle Repair(HNR) process to prevent the leakage from welds on small bore piping in Reactor Coolant System. The Codes & Standards of tempered bead and design requirements of J-Groove welds are reviewed. Automatic machine GTAW welding and machining equipments are developed to perform HNR process. Single pass welding and overlay welding equipments are conducted in order to obtain the optimal temper bead welding process parameters with Alloy 52M filler wire. Coarse grain heat affected zone(CGHAZ) is formed by rapid cooling rate in heat affected zone after welding. Accordingly, a proper temper bead technique is required to reduce CGHAZ in 1-Layer of welds by 2- and 3-Layers. Mock-up tests show that the developed HNR process is possible to meet ASME Code & Standard requirements without any defect.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.80-87
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• 2007

This paper will suggest that the 1 cross orthogonal loop type sensor improves on the orthogonal loop form sensor-head, which is available a calibration of the linear birefringence, when a fiber optic current sensor was composed. An output characteristics of the 1 cross orthogonal loop form, a general closed loop form, the orthogonal loop form are compared by the IEC(International Electrotechnical Commission) 60044-8 standard, and the state of polarization is compared with three forms. As a result, when the closed loop form was changed to the orthogonal loop form, retardation decreased 15.3[%]. When the closed loop form was changed to the 1 cross orthogonal loop type, the retardation decreased 33.8[%]. As a result of the Faraday Effect measurement, the 1 cross orthogonal loop form has the highest output characteristic and the lowest error ratio. It met the 0.5 class of the IEC 60044-8 standard. Thus, in application of the 1cross orthogonal loop form, the possibility to develop high reliability fiber optic current sensors that have a high output and stable error ratio rises is increased.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.115-121
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• 2007

This paper describes experiments of the breakdown characteristics by temperature change of $SF_6$ gas and Imitation Air(I-Air) in model GIS(Gas Insulated Switchgear). From the results of the experiments, the breakdown characteristics classify the vapor stage of $SF_6$ according to Paschen's law, in which the stage of coexistence for gas & liquid of the voltage value increases. This results in large deviation and the breakdown of the voltage(VB) low stage as the interior of the chamber is filled with a mixture of $SF_6$ that is not liquefacted and remaining air that can not be ventilated. The ability of $SF_6$ liquid($LSF_6$) insulation is higher than high-pressurize $SF_6$ gas. The VB of the I-Air decreases as the temperature drops and the VB also drops. It is considered that the results of this paper are fundamental data for the electric insulation design of superconductor and cryogenic equipment that will be studied and developed in the future.

• 터널과지하공간
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• 제17권1호
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• pp.9-16
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• 2007

굴진장이 터널의 안정성 및 시공비에 미치는 영향에 대해서는 많은 연구자와 기술자들이 잘 알고 있지만, 아직 굴진장 결정에 대해서 일관된 절차가 수립되지는 못한 실정이다. 본 연구에서는 굴진장을 고려한 연암터널의 막장과 무지보 구간의 거동형태를 실내모형실험, PFC3D 및 FDM 해석을 통하여 조사하였다. 총 다섯 개의 거동형태를 정의하였고, 막장 안전율과 설계 도표를 통해 거동형태를 정량적으로 판단할 수 있도록 하였다. 비록 본 연구에서 제안한 방법이 몇몇 제한을 갖지만, 굴진장과 굴착의 최적화를 위한 유용한 정보를 제공할 수 있을 것으로 사료된다.

• KIEAE Journal
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• 제9권1호
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• pp.91-97
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• 2009

In this thesis presents the application to the field of Hwangto-used concrete highlighted as an eco-friendly material and performs an experiment in the aspect of construction and quality on the construction for all parts of buildings, rather than for some parts of buildings as shown from existing application and got the conclusion as followings. 1) It was turned out that Hwangto concrete showed lower hydrated heat and arid contraction comparing to those of cement concrete. And this phenomenon is judged to appear high when applied to mass building and huge span structures. 2) The construction of Hwangto concrete is judged to be possible in applying to constructions since the mechanical construction seems to be possible by using pump car and ready-mixed concrete which are used at the practical sites at the moment. 3) The pockmarks appearing on the exposure surface were about 2% of total area. This has great cohesion by Hwangto concrete but is judged that it will be improved through enough vibration stamping. Through the experiments of quality and construction of Hwangto concrete as environment-friendly construction materials, it is possible to judge modernized application of Hwangto concrete. It is in need of more studies about economical efficiency, structural stability, design application, etc. afterwards.

• 한국지리정보학회지
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• 제19권3호
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• pp.16-28
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• 2016

공간정보 웹 서비스 기술과 응용 분야의 발전에 따라 서로 다른 운영 플랫폼과 브라우저 환경들에서의 호환성과 상호운용성을 위한 기술적 고려가 필요한 상황이다. 또한 웹 시스템 구현에 필요한 공통요소 및 지원요소의 중복성 문제가 발생하는 경우도 있다. 이러한 문제에 대하여 국제표준기구인 OGC에서 개발한 공간정보와 관련된 표준들을 이해하고 적용하는 것이 적절한 해결 방안이 될 수 있다. 따라서 현재 공간정보 웹 서비스 설계와 개발에서 서비스 목적과 환경에 적합하도록 OGC 표준들을 적용하는 것은 핵심 고려사항이다. 특히 목표 시스템이 웹상에서의 실제 공간정보 처리기능을 지원하는 경우에는 WPS를 고려해야 한다. 그러나 최근에 발표된 WPS 2.0 표준에 대한 연구는 아직 초기 응용단계이다. 본 연구에서는 WPS 2.0의 주요 특징이라고 할 수 있는 다양한 프로세스의 동시 처리를 가능하게 하는 비동기식 처리기능을 제공하는 기초 운영 환경 구축에 주안점을 두고 웹 기반 공간정보 분석서비스를 위한 시험 시스템을 구현하였다. Binary thresholding 알고리즘을 적용한 사례를 제시하였으며 향후 다중 사용자의 다중 알고리즘 동시 사용요청에 대한 실험을 계속 연구로 수행할 예정이다. 예시 시스템은 jQuery와 OpenLayers를 이용한 클라이언트 시스템과 Spring 프레임워크를 기반으로 ZOO 프로젝트와 Geoserver등의 오픈소스를 적용한 서버 시스템으로 구성하였다. 이번 연구에서 제시된 모델과 처리 결과는 실제 사용자 환경에서 WPS 적용성과 확장성을 위한 참고모델로 이용될 수 있다.

• 한국화예디자인학연구
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• 제42호
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• pp.37-62
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• 2020

흙은 그 자체로 자연치유력을 가진 동시에 친환경적이며, 정서적, 심리적인 안정감을 주는 천연 재료이다. 이 논문에서는 치유공간으로서의 기능을 확대하기 위한 방안의 하나로 한의원인테리어의 건축에 흙의 효과성을 적극적으로 활용한 설계와 시공방식을 구체화하였다. 특히 바이오필릭(Biopillic) 디자인 개념을 치유환경 디자인으로 활용하여 자연을 상징하는 색채, 빛, 식물, 꽃, 자연재료인 흙, 목재 등을 치유공간인 한의원인테리어로 연출하였다. 이 가운데 환자들의 동선에 따른 공간을 구획하고 공간별 특성에 따른 흙건축 공법을 적용하였다. 이때 흙은 첨가재를 넣지 않은 친환경 건축자재 인증등급 HB(Healthy Building)의 최우수 등급에 준하는 재료와 마감재인 흙으로 시공하여 인테리어와 치료개념을 동시에 연출가능 하도록 하였다. 본 연구결과는 향후 치유공간을 구성하는 데 바이오필릭((Biophilic) 디자인을 활용한 치유공간요소의 대입으로 시공의 설계와 흙건축 공법의 활용에 필요한 토대로 작용할 수 있을 것이다. 또한, 미래지향적 대안으로 건축디자인에 흙의 활용 영역을 확장시킬 수 계기가 될 수 있을 것이다.

• 조명전기설비학회논문지
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• 제27권1호
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• pp.85-91
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• 2013

This paper studied surface discharge characteristics by a dielectric constant and diameter of solid dielectrics in $N_2/O_2$ mixture gas. Applied electric field strength at $N_2/O_2$ mixture gas was changed from the dielectric constant and diameter of the solid dielectrics, and insulation performance of the $N_2/O_2$ mixture gas determined surface discharge voltage. In each of the diameter at the solid dielectrics, the surface discharge voltage was increased by lengthening surface distance, whereas increasing rate of the surface discharge voltage was different from gas pressure. Thus, In this paper, main factors of surface discharge are as follows. 1) Insulation performance of $N_2/O_2$ mixture gas, 2) Dielectric constant of solid dielectrics, 3) Surface discharge path. It was clear that the surface discharge voltage depend on the main factors. These results will be applied to useful data for an eco-friendly composite insulation design.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.603-609
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• 2015

Dry air is an excellent alternative to $SF_6$ gas and is used as an insulation gas in Eco-friendly Gas Insulated Switchgears (EGISs), which has gained popularity in industry. Solid insulators in EGIS play an important role in electrical insulation. On the other hand, surface discharge can occur easily when solid insulators are used. This paper explored the surface discharge characteristics on the structure of three-layered laminated solid insulators to elevate the flashover voltage. A laminated solid insulator was inserted after the quasi-uniform electric field was formed in the test chamber. Dry air was then injected to set the internal pressure to 1 ~ 6 atm, and the AC voltage was applied. When identical solid insulators were stacked, the surface discharge characteristics were similar to those of a single solid insulator. On the other hand, the flashover voltage rose when the middle part was thicker and had lower permittivity than the top and bottom parts in the laminated solid insulator. Based on experimental results, when stacking a solid insulator in three layers, the middle part of the solid insulator should be at least four times as thick as the top and bottom parts and have lower permittivity than the others. In addition, the flashover voltage increased with increasing gas pressure on the surface of the laminated solid insulator due to the gas effect. This study may allow insulation design engineers to have useful information when using dry air for the insulation gas where the surface discharge can occur.

• Current Photovoltaic Research
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• 제2권4호
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• pp.168-172
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• 2014

Under concentrated illuminations, the solar cells show higher efficiencies mainly due to an increase of the open circuit voltage. In this study, InGaP/InGaAs/Ge triple-junction solar cells have been grown by a low pressure metalorganic chemical vapor deposition. Photovoltaic characteristics of the fabricated solar cells are investigated with a class A solar simulator under concentrated illuminations from 1 to 100 suns. Ideally, the open circuit voltage should increase with the current level when maintained at the same temperature. However, the fabricated solar cells show degraded open circuit voltages under high concentrations around 100 suns. This means that the heat sink design is not optimized to keep the cell temperature at $25^{\circ}C$. To demonstrate the thermal degradation, changes of the device performance are investigated with different bonding conditions and heat sink materials.