• 한국환경과학회지
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• 제22권9호
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• pp.1199-1211
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• 2013

Mobile sources produce a significant fraction of total anthropogenic emissions in Korea and have harmful effects on air quality. Mobile emissions are intrinsically difficult to estimate due to complicated road networks and variations of traffic volume with location and time. To measure traffic pollutants with high temporal and spatial resolution under real conditions a mobile laboratory was designed. The mobile laboratory provide concentrations of $SO_2$, CO, NO, $NO_2$ and location coordinate value. This approach allowed for pollutant level measurements on many roads within short periods of time. In this study, on-road concentrations of $SO_2$, CO, NO and $NO_2$ were measured using mobile platform measurement along the 25 main roads in Busan to estimate the average air pollution level in short time difference. The measurements were conducted on favorable meteorological days from 2010 to 2012 and the overall concentrations of $SO_2$, CO, NO and $NO_2$ were 0.006, 0.8, 0.182 and 0.055 ppm respectively. The result showed that the concentration of CO, NO and $NO_2$ on road were twice, 18 times and 2.5 times higher than regional air quality monitoring sites mean in same period.

• Journal of the Korean Data and Information Science Society
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• 제25권6호
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• pp.1293-1300
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• 2014

기온의 변화는 국가 정책에 여러 가지 영향을 준다. 본 연구에서는 충청남도 서산시 2003년 ~ 2012년 기온을 주위에서 쉽게 구할 수 있는 기상자료, 온실가스자료, 대기자료를 이용하여 자기회귀오차 (autoregressive error)모형으로 월별과 계절별로 분석하였다. 기온을 위한 기상자료로는, 풍속, 강수량, 일사량, 운량, 습도를 사용했고, 온실가스자료는 이산화탄소 ($CO_2$), 메탄 ($CH_4$), 아산화질소 ($N_2O$), 염화불화탄소 ($CFC_{11}$), 대기자료는 미세먼지 ($PM_{10}$), 이산화황 ($SO_2$), 이산화질소 ($NO_2$), 오존 ($O_3$), 일산화탄소 (CO)를 사용하였다. 분석 결과, 자기회귀오차모형으로 월별 기온을 39%-63% 정도 설명할 수 있다.

• 한국표면공학회지
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• 제55권2호
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• pp.120-132
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• 2022

In the non-cyanide-based electroless Au plating solution using thiomalic acid as a complexing agent and aminoethanethiol as a reducing agent, analysis of each component constituting the plating solution is essential for the analysis of the reaction mechanism. And component analysis in the plating solution is important for monitoring component changes in the plating process and optimizing the management method. Capillary Electrophoresis (CE) method is rapid, sensitive and quantitative and could be readily applied to analysis of Auⁿ⁺ ion, complexing agent and reducing agent in electroless Au plating solution. In this study, the capillary electrophoresis method was used to analyze each component in the electroless Au plating solution in order to elucidate the complex bonding form and the plating mechanism of the non-cyanide-based electroless Au plating bath. The purpose of this study was to establish data for optimizing the monitoring and management method of plating solution components to improve the uniformity of precipitation and stability. As a result, it was confirmed that the analysis of thiomalic acid as a complexing agent and Auⁿ⁺ ions and the analysis of aminoethanethiol as a reducing agent were possible by capillary electrophoresis. In the newly developed non-cyanide-based electroless Au plating solution, it was confirmed that Auⁿ⁺ ions exist in the form of Au⁺ having a charge of +1, and that thiomalic acid and Au⁺ are combined in a molar ratio of 2 : 1. In addition, it was confirmed that aminoethanethiol can form a complex by combining with Au⁺ ions depending on conditions as well as acting as a reducing agent.

• 대한의생명과학회지
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• 제29권2호
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• pp.81-87
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• 2023

Pan-Enterovirus (Pan-EV) infects millions of children and infants worldwide every year. As severe infections have recently been reported, the need for monitoring has consequently intensified. Pan-EV is a categorical name for waterborne enteroviruses belonging to the Picornaviridae family, and includes a wide range of pathogens including Coxsackievirus (CoxV), Echovirus (EcoV) and Enterovirus (EV). In this study, we proposed an optimal RT-nested PCR method for diagnosis of various types of Pan-EV in an aquatic environment and developed a positive control. Considering detection sensitivity, specific reaction, and final identification, one condition capable of amplifying 478 bp among the four candidates in the 1^st round PCR (RT-PCR) and one condition in the 2^nd round PCR (nested PCR) were selected. Through the detection of nucleic acids extracted from 123 groundwater samples and the detection sensitivity test based on artificial spiking in the sample, the methods are optimal for non-disinfected water samples such as groundwater. We developed a positive control for Pan-EV detection that can be amplified to different sizes under the two conditions. Accuracy could be further improved by testing for contamination from the control group. The method proposed in this study and the positive control developed are expected to be used in monitoring Pan-EV in aquatic environments including groundwater through future research using more samples.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1349-1352
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• 2005

This paper is to investigate a defect for thermal barrier coating layers by acoustic emission method in 4-point bending test. The two-layer thermal barrier coating is composed of $150\mu{m}\;CoNiCrAlY\;bond\;coating\;by\;vacuum\;plasma\;spray(VPS)\;process\;and\;250\mu{m}\;ZrO_2-8wt%Y_2O_3$ ceramic coating layer by air plasma spray(APS) process on Inconel-718. The specimen prepared by cyclic thermal test(500, 1000, 2000cycle) at $1050^{\circ}C$ The AE monitoring system is composed of PICO type sensor, a wide band pre-amplifier(40dB), PC and AE DSP(16/32 PAC) board. The AE event, amplitude, Cumulative energy and count of coating specimens is evaluated according to cyclic thermal test.

• 한국가스학회지
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• 제23권5호
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• pp.15-23
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• 2019

최근 5년간 국내 가스 사고 중 약 42.5%가 인적요소에 의해 발생하였고, 38%가 주택에서 발생, 또한 2017년 대비 제품 노후 / 고장으로 발생한 사고가 1년 사이에 2배 이상 급증하여 가정 내 가스시설 노후화에 대한 대비책이 필요하나 현재는 모니터링 수준에서 그치고 있어 가정 내 가스시설에 대한 예측 및 예방이 불가능한 상황이다. 본 연구에서는 LPWA 양방향 통신 방식을 통해 모니터링 및 원격 제어 기능을 구현하여 99.32%의 데이터 송수신 정확도를 확보한 IoT 기반 가정 가스시설 안전 플랫폼 서비스를 구축 및 개발하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권6호
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• pp.18-31
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• 2013

This study was performed to examine use of the pump-and-treat method for remediation of TCE, CF and CT in groundwater contaminated by DNAPL. The Woosan industrial complex is located in Wonju, about 120 km east of Seoul, Korea. Two pumping wells (KDPW7 and KDPW8) and five monitoring wells (KDMW7, KDMW8, KDMW9, KDMW10, and SKW2) were installed for the test. An asphalt laboratory is a main source of the extensive subsurface contamination at this site. To evaluate change in the concentrations of TCE, CF, and CT in groundwater in the study area, three rounds of pump-and-treat pilot tests were performed (6 July to 6 August, 22 August to 6 September, and 19 September to 2 December in 2011). The groundwater levels and the concentrations of TCE, CF, and CT exhibited negative correlations in the wet season but positive correlations in the dry season, which suggests that the TCE concentrations were mainly controlled by dilution through rainfall during the wet season and by residual TCE, CF, and CT in the unsaturated zone during the dry season. These possibilities should be considered in the full-scale remediation plan.

• 한국군사과학기술학회지
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• 제27권2호
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• pp.294-303
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• 2024

The objective of condition-based maintenance plus(CBM+) is to improve the availability and maintenance efficiency of missiles, bolstering national defense capabilities. This study proposes an application of CBM+ to enhance the reliability and the safety of missiles, which are the devices typically stored for long durations. CBM+ CBM+ does not only contribute to defense capabilities, but it also aims to reduce maintenance costs. This study focuses particularly on the dormant stage of the missile life-cycle, in which various failure modes and environmental impacts on failure mechanisms are investigated. The effectiveness of maintenance strategies and the implementation of CBM+ is evaluated using simulation data.

• Nuclear Engineering and Technology
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• 제55권12호
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• pp.4628-4636
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• 2023

Cables are indispensable in nuclear power plants for transmitting data measured by various types of detectors, such as self-powered neutron detectors (SPNDs). These cables will generate disturbing signals that must be accurately distinguished and eliminated. Given that the cable current is not very significant, previous research has focused on SPND, with little attention paid to cable evaluation and validation. This paper specifically focuses on the quantitative analysis of cables and proposes a theoretical model to predict cable noise. In this model, the reaction characteristics between irradiated neutrons and cables were discussed thoroughly. Based on the Monte Carlo method, a comprehensive simulation approach of neutron sensitivity was introduced and long-term irradiation experiments in a heavy water reactor (HWR) were designed to verify this model. The theoretical results of this method agree quite well with the experimental measurements, proving that the model is reliable and exhibits excellent accuracy. The experimental data also show that the cable current accounts for approximately 0.2% of the total current at the initial moment, but as the detector gradually depletes, it will contribute more than 2%, making it a non-negligible proportion of the total signal current.

• Journal of Electrical Engineering and Technology
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• 제13권6호
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• pp.2402-2411
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• 2018

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.