• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.615-617
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• 2005

대기중에 위치한 뇌운안에 전하가 떠다니는 상태에서는 구름안과 주변에 높은 전계의 전위가 발생한다. 이 전하가 축적되면 대지 방전이 발생하고 송전선로 등에 뇌격이 침입하게 된다. 뇌 방전은 수 km에 달하는 대기중에 발생하는 거대한 전기현상이지만 이 낙뢰가 전기의 흐름이라는 것은 벤자민 프랭클린의 현장 시험에 대해 최초로 증명되었다. 이러한 대기중에 발생하는 거대한 전기현상인 낙뢰가 송전선로에 침입하여 송선선로 애자련을 섬락시키는 과정은 대단히 복잡한 전자기적인 현상이다. 그것은 가스 방전 현상, 감속에 중요한 역할을 하는 전자계의 빠른 변화, 도체와 철탑에 나타나는 코로 나와 관련된 비선형 효과 및 주파수 및 전류와 관련된 대지의 임피던스 통 다양한 현상이 종합적으로 관련된다. 따라서 가공 송전선로의 낙뢰에 대한 동작특성의 평가시 낙뢰 현상의 불규칙한 특성 및 신뢰할만한 데이터의 부족에 따른 많은 불확실성이 존재한다. 이 때문에 가공 송전선로에서 낙뢰에 의한 트립(Trip) 사고수의 계산을 위해 단순화된 방법이 아주 유용하며 효과적일 수 있다. 본 논문에서는 EGM (Electrogeometric Model) 모델을 사용하여 대지경사자의 크기에 따른 차폐실패 트립 사고율의 영향을 검토하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.191-192
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• 2010

This study is a field application of high density concrete for a radiation shield at Korea Atomic Energy Research Institute. There are each process of investigation of using materials, producing arrangements, and field application products to satisfy presented specifications.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.9
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• pp.782-789
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• 2018

Multi-Function Display (MFD) of Korean Utility Helicopter (KUH) displays image information(navigation, flight, topographical and maintenance information) delivered from Mission Computer (MC) during flight operation. The abnormal display of MFD such as flickering phenomenon was identified in the system development. It was solved by improving the shielding performance of the DVI cable and changing the DVI cable installation path at the first mass production. However, it was occurred again when the aircraft was operated for one or two years after delivery. It was also identified in the evaluation process of the derivative helicopters. Therefore, a comprehensive review of the aircraft system level has been performed to solve the problem of MFD malfunction at first and then a design improvement plan was derived by improving the DVI cable. In this paper, the causes of MFD anomalies are analyzed and also the process of design improvement are summarized. The validity of the improvement has been verified through the DVI cable assembly comparison test, SIL/ground/flight test.

• Resources Recycling
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• v.33 no.4
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• pp.29-35
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• 2024

The recycling of waste resources, such as spent catalysts, primarily involves leaching and extracting metal components via smelting. These metal components are then recovered as salts, such as sulfates and nitrates. When crystallization occurs during the calcination of the recovered salts, the salts are converted into oxides, which are then reduced to form metals or ceramic materials. Common reducing agents used in oxide reduction include hydrogen and carbon, and metal powders are obtained upon reduction. Carbide synthesis can occur if the recycled element is a transition metal and carbon is used as the reducing agent. Despite being ceramic materials, transition metal carbides exhibit excellent conductivity owing to their metallic bonding. Recently, MXene, a two-dimensional transition metal carbide, has gained attention for electromagnetic wave shielding, secondary battery electrodes, and water purification owing to its electrical conductivity and large surface area. This study developed a process for synthesizing high-value MXene materials from waste resources. The properties of these MXenes were evaluated to confirm the potential of using waste resources as raw materials for MXenes.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.2043_2044
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• 2009

한국전력은 765kV 송전선(2,000A/single phase)에 ball sensor를 설치할 계획이다. 우리의 이전연구에서는 다중 Mu-metal 케이스를 설치한 후 여러 조건하에서 센서의 정상동작여부와 차폐효율을 연구하였다. 이번연구에서는 Mu-metal 케이스의 겹 수와 형상에 따른 차폐효율을 연구할 것이다. 차폐효율은 전류가 커짐에 따라 감소하는 것을 보이며, Mu-metal 케이스의 자속경로가 길어짐에 따라 감소하는 것을 알 수 있었다. Ball sensor의 형상에 따른 차이를 고찰하기 위하여 실제 실험 전에 실제 실험과 동일한 조건으로 시뮬레이션툴을 사용하여 모의 하였으며 그에 따른 실험을 수행하였다. 이런 방식으로 실제 실험 전에 관련 실험의 결과를 예측 가능하였다. 이러한 일련의 과정을 통해 이상적인 Mu-metal 케이스의 형상과 겹 수를 찾을 수 있었다.

• Explosives and Blasting
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• v.23 no.2
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• pp.23-35
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• 2005

Excavation of an opening in a saturated porous rock may lead to the development of pore pressure around the opening due to the redistribution of initial rock stresses. The built-up of pore pressure, in turn, may affect the mechanical behavior of rock mass and give the different pattern of stress distribution around the opening from that of the case where the coupling is neglected. In this study, the short time response of an opening excavated in saturated ground under anisotropic initial stress conditions was investigated numerically. Not on the wall of opening but at a short distance from the wall, the tangential stresses were peak during the short period after excavation when the hydro-mechanical coupling is considered.

• Journal of Radiation Protection and Research
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• v.11 no.1
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• pp.29-36
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• 1986

GESS-a computer code for simulation of energy spectra for gamma-ray in NaI(T1) scintillator has been developed. The Monte Carlo method was employed to simulate physical behaviours of particle transport in a medium. In the processes of simulation, all the interaction processes such as Rayleigh and Compton scattering, photoelectric effect and pair production were considered. The resulting electron slowing down spectrum was also considered with the CSDA model. For the purpose of verification of the code, a measurement gamma spectrum for incident gamma energy of 1.33 MeV was performed. The measured values appeared to be slightly higher than the theoretically calculated values.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.186-187
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• 2008

Electrical resistivity in hydrate-bearing sediments is sensitive to porosity, gas hydrate saturation, gas content, pore fluid composition, and temperature, so electrical measurements such as well logs and electromagnetic surveys have been used to explore gas hydrate-bearing formation. The high pressure tomography cell is designed considering the effect of electrode configuration and electrical shielding on tomography measurements and the safety. The evolution of electrical conductivity during $CO_2$ hydrate formation and dissociation reflects the combined effects of concurrent changes that include ionization of dissolved $CO_2$, temperature-dependent ionic mobility, changes in the degree of saturation, ion exclusion, surface conduction, and porosity changes. Measurements during hydrate formation and dissociation require careful analysis to properly interpret signatures, in particular when out-of plane conductivity anomalies prevail.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.707-719
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• 2003

The D&D work requires worker's safety and high reliability of operation because it has been processing in high radioactive environment. Therefore, it is necessary to select the dismantling items and applicable dismantling technologies and analyze the scenarios for selected items. In this paper, the main dismantling items were selected by the consideration of several factors, their 3D CAD models were constructed as well. The applicable dismantling technologies for each dismantling items were selected and their dismantling scenarios were setup. Finally the 3D graphic simulations for the shielding concrete, the RSR, and the core are performed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.12 no.1
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• pp.77-83
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• 2001

We analyzed the mechanism of EM emission in telecommunication system and extracted the dominant parameter in EMC design. The I/O cable, ventilation hole and shield design of chassis are important EMC design Issues in telecommunication systems. Because telecommunication systems have much more I/O cables than other electronic products, EMC design of I/O cable is very important in telecommunication systems. Therefore by the method of experimentation and simulation, EM coupling mechanism of I/O cable was analyzed and the design rule for low emission was extracted. On the base of these EMC design rules, EMC design of telecommunication system was executed without complex redesign or debug. The result obtained by these methods was shown in this paper.