• Journal of the Korean Electrochemical Society
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• v.23 no.1
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• pp.1-10
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• 2020

DSA (Dimensionally Stable Anode) electrodes are physically, thermally and electrochemically stable and are mainly Ti electrodes coated by Ru, Ir and Ta. DSA electrodes have been used in many industrial fields such as chlor-alkali, electrochemical water treatment, water electrolysis, etc. This review paper summarizes the study on the applications using DSA electrodes published in the recent 5 years. It suggests that the researches are intensively required on effective screening of electrodes materials, optimal designing of electrode structures and economical manufacturing of large area electrodes. It is expected that these studies will contribute to the further research and development on advanced DSA electrodes. In addition, the enhancement of DSA electrodes significantly leads to expand the type of the application using electrochemical processes in industry.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.11
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• pp.905-911
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• 2015

In this study, to examine the effect of a hole size change(smaller hole diameter) in the outer region of the lower-support-structure-bottom plate(LSSBP) on the reactor core-inlet flow-distribution, simulations were conducted with the commercial CFD software, ANSYS CFX R.15. The predicted results were compared with those of the original LSSBP. Through these comparisons, it was concluded that a more uniform distribution of the mass flow rate at the core-inlet plane could be obtained by reducing the hole size in the outer region of the LSSBP. Therefore, from the nuclear regulatory perspective, design change of the hole pattern in the outer region of the LSSBP may be desirable in terms of improving both the mechanical integrity of the fuel assembly and the core thermal margin.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.11
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• pp.26-34
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• 2006

The thermo-mechanical analysis and test were performed for plate structure under mechanical and thermal loading conditions. Infrared heating system and hydraulic loading system were used to simulate mechanical and thermal environment for the plate structure which is similar to the fin of the airframe. Also, FEM analysis using plastic option was added to evaluate thermo-mechanical behavior. Thermo-mechanical tests were conducted at elevated temperature and rapid heating(10℃/sec) condition with external loading together. To investigate the effect of heating environment, the strength at room temperature was compared with that of elevated temperature and rapid heating condition. A methodology for test and analysis for supersonic vehicle subjected to aerodynamic loading and heating was generated through the study. These experimental and analysis results can be used for designing thermal resistance structures of the supersonic vehicle.

• CRM연구
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• v.1 no.1
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• pp.49-69
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• 2006

Previous studies, Technology Acceptance Model (TAM) and Post Acceptance Model (PAM) have a little limitation in time series analysis. To solve this limitation, we used system dynamics as research methodology and designed simulation model based on TAM and PAM. Moreover, we designed new simulation model which can analyize time series data in customers' demand change from initial acceptance to post acceptance. This study targeted domestic mobile phone market. The simulation results showed that diffusion graph was similar to real data. That means we validated our simulation model. Since the simulation model offers the graph of customer's demand change by time, so it can be useful as a leaning tool. Therefore, we think this study helps IT companies use the model for forecasting of market demand.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.86-88
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• 1997

The detection of the normal zones in the coil winding and the initiation of the proper dump sequence have been one of the most important areas in the superconducting magnet technology. In this paper, the process to derive optimal dump sequence has been investigated through quench simulation and analysis of magnetically coupled superconducting magnet system. The magnet terminal voltage and maximum temperature rise in the quench initiated point are calculated with respect to various input variables such as operation current, dump resistance, etc. The experimental system is comprised of sc solenoidal coil, data aquisition device, external circuit breakers and dump resistor. The quench behavior of the magnet(e.g., temperature profile and the voltage signal) was measured. From this results, theoretical predictions were found to coincide with the experimental observations.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.91-92
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• 2013

산업이 고도화, 다원화, 세계화되고 있는 현대사회는 다기능성, 고물성, 극한 내구성을 가지며 환경 친화적이면서 에너지 효율을 극대화시킬 수 있는 다기능 소재의 개발을 요구하고 있다. 이러한 시점에서 다양한 물성을 동시에 발현이 가능한 코팅 소재는 향후 미래에 중요한 원천 소재로서 주목되고 있다. 특히, 환경에 의해 쉽게 물성 및 구조의 변화가 쉬운 종래의 코팅소재와는 달리, 다양한 외부환경에서도 미세 구조 및 물성을 안정적으로 유지할 수 있는 신개념의 코팅 소재의 개발이 절실히 요구되고 있다. 이를 위해서는 코팅소재의 다 성분화가 필수적이다. 최근의 코팅 기술은 2가지 이상의 물성, 특히 서로 상반되는 물성을 동시에 구현할 수 있는 소재의 개발을 요구하고 있다. 이러한 물성의 구현을 위하여 더 많은 성분으로 구성되며 더욱 복잡한 조직으로 구성된 코팅층에 대한 개발이 필요하다. 본 연구에서 목표로 하는 신 개념의 원천소재기술은 4성분계 이상의 원료 물질을 단일 타겟으로 제조하여, 단순한 코팅공정으로서 단일 코팅층 내에 다양한 성분상이 10 nm 미만 크기의 나노 결정립/나노 비정질로 구성된 나노 복합 구조로 형성되도록 하는 기술을 개발하고자 하는 것이다. 이는 복합기능 3 이상의 다기능성 부여는 물론, 그림 1에 명시되어 있는 극한 기능성(광대역 윤활성, 전자 이동 제어에 의한 온도 저항 계수 및 전기 저항 조절, 고온 열적 안정성, 내산화성, 고열전도율, 초저마찰/내구성/초고경도성 등)이 구현되도록 하는 소재 개발과 원하는 물성을 구현할 수 있는 나노 복합 코팅층의 형성 공정으로 구성된다. 다성분계 모물질의 개발이 중요한 이유는 다수의 성분 원소를 합금 상태로 형성시킴으로서, 단일 소스에 의해 다양한 원소를 동시에 스퍼터링 및 증착이 가능하도록 할 수 있다는 장점을 가지기 때문이다. 특히, 타겟의 미세구조를 나노구조화 하는것을 통해, 스퍼터링 yield의 차이가 큰 원소일지라도 균일하게 증착시킬 수 있는 방법을 제시하고자한다. 이러한 연구는 다수의 성분 타겟을 사용함으로서 장비의 복잡성, 코팅의 재현성, 대형화 등의 문제점을 본질적으로 갖고 있는 기존 PVD 공정의 문제점을 해결하기 위한 최적의 대안이라할 수 있다. 본 발표에서는 3가지 이상의 다기능성 구현을 위한 가장 중요한 원천기술이라 할 수 있는 다성분계 타겟 모물질 제조 기술과 제조된 모물질을 이용하여 제조된 저마찰 코팅층과 그 물성에 대해 소개하고자 한다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.31-38
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• 2005

This paper is focused on the research of environmental and human factors for a design of PMVbased air conditioning system in the ship. In the results from environmental factor research, it is possible to dissatisfy thermally in the wheel house and communication room of 25 ton and engine room of 100 ton. The clothing and activity in the ship is modified using inland indoor characteristics. Thermal resistance of clothing may be more sensitive to PMV(predicted mean vote) than metabolic rate because of large deviation among maritime polices. The distribution of human factor is right long-tailed than standard normal distribution.

• Journal of the Korea Convergence Society
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• v.10 no.12
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• pp.17-22
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• 2019

Network attack analysis and visualization methods using network traffic session data detect network anomalies by visualizing the sender's and receiver's IP addresses and the relationship between them. The traffic flow is a critical feature in detecting anomalies, but simply visualizing the source and destination IP addresses symmetrically from up-down or left-right would become a problematic factor for the analysis. Also, there is a risk of losing timely security situation when designing a visualization interface without considering the temporal characteristics of time-series traffic sessions. In this paper, we propose a visualization interface and analysis method that visualizes time-series traffic data by using the radial axis, divide IP addresses into network and host portions which then projects on the cylindrical coordinate system that could effectively monitor network attacks. The proposed method has the advantage of intuitively recognizing network attacks and identifying attack activity over time.

• Journal of the Korean Recycled Construction Resources Institute
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• v.5 no.4
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• pp.414-420
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• 2017

The thermal characteristics of concrete fabricated with blast furnace slag were investigated in this paper. Test parameters included water-binder ratio and the content of furnace slag. Experimental program were performed to measure mechanical properties including compressive strength and split tensile strength under high-temperature thermal cycling, and to measure thermal properties including thermal conductivity and specific heat. Test results showed that the residual compressive strength of mixtures with blast furnace slag was greater than that of mixture without blast furnace slag. In addition, thermal conductivity of mixtures with blast furnace slag was greater than that of mixtures without blast furnace slag. It indicates that blast furnace slag was favorable for charging and discharging in thermal energy storage system. Test results of this study would be used to design concrete module system of thermal energy storage.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.5
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• pp.45-50
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• 2010

Thermal analyses have been performed to study the effect of location of fuel ring and thermal barrier coatings in regenerative cooling channels in a full-scale combustor. For the effective cooling, the fuel ring has better be installed near axial location of the low expansion ratio and low heat flux, and branching of cooling channels is preferable. Also, the radiative cooled nozzle extension is thought to be reasonable for the cooling of combustor walls. Among the possible coatings, $Y_2O_3$ stabilized $ZrO_2$ coating and Ni/Cr coating have been adopted. Compared with Ni/Cr coating which has high oxidation resistance, $Y_2O_3$ stabilized $ZrO_2$ coating, one of ceramic coatings is found to be much effective to sustain the thermal survivability of combustion walls.