• 수산해양기술연구
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• 제59권1호
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• pp.19-27
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• 2023

The interest in greenhouse gases (GHG) emitted from all industries is emerging as a very important issue worldwide. This is affecting not only the global warming, but also the environmentally friendly competitiveness of the industry. The fisheries sector is increasingly interested in greenhouse gas emissions also due to the Paris Climate Agreement in 2015. Korean industry and government are also making a number of effort to reduce greenhouse gas emissions so far, but the effort to reduce GHG in the fishery sector is insufficient compared to other fields. Especially, the investigation on the GHG emissions from Korean fisheries did not carry out extensively. The studies on GHG emissions from Korean fishery are most likely dealt with the GHG emissions by fishery classification so far. However, the forthcoming research related to GHG emissions from fisheries is needed to evaluate the GHG emission level by species to prepare the adoption of Environmental labels and declarations (ISO 14020). The purpose of this research is to investigate which degree of GHG emitted to produce the species (swimming crab and snow crab) from various fisheries. Here, we calculated the GHG emission to produce the species from the fisheries using the life cycle assessment (LCA) method. The system boundary and input parameters for each process level are defined for LCA analysis. The fuel use coefficients of the fisheries for the species are also calculated according to the fuel type. The GHG emissions from sea activities by the fisheries will be dealt with. Furthermore, the GHG emissions for producing the unit weight species and annual production are calculated by fishery classification. The results will be helpful to establish the carbon footprint of seafood in Korea.

• 한국터널지하공간학회 논문집
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• 제24권1호
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• pp.39-55
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• 2022

본 연구는 경주 중·저준위 지하 처분환경에서의 사일로 콘크리트의 음향방출(AE) 신호 감쇠계수(α)를 결정하기 위해 신호감쇠 실험을 수행하였다. 활용된 시료들은 경주 중·저준위 처분장 사일로에 사용된 콘크리트 배합비로 제작하였으며 28일간 수중 양생 후 처분환경에 맞도록 온도 및 포화유무에 따라 추가적으로 노출시켰다. 처분조건 별 각 3개씩의 공시체에 대하여 신호전달거리에 따른 AE 신호를 측정한 결과, 초기구간에서는 포화콘크리트의 AE 진폭과 절대에너지가 건조콘크리트의 경우보다 더 높게 나타났지만, α는 포화콘크리트의 경우가 더 높게 산정되었다. 또한, 포화유무와 상관없이 온도가 증가함에 따라 α는 감소하는 경향을 보였다. α는 온도조건보다는 포화유무에 따른 영향이 큰 것으로 분석되었으며, 이는 콘크리트 처분구조물의 감쇠신호 측정 시 포화여부를 고려한 판단이 중요하다는 것을 의미한다. 처분환경에서의 콘크리트 α는 균열이 발생한 위치에서의 실제 AE 특성 파라미터 값을 추정함으로써 경주 중·저준위 처분환경에서 사일로 콘크리트의 건전성을 예측하고 센서의 최적 배치를 결정하는 데 도움이 될 것으로 기대한다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.407-408
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• 2002

This paper presents a split cooling system for a new inline 4-cylinder automotive engine. The split cooling system circulates coolant to the cylinder head and cylinder block separately. The coolant flow in the cylinder block is controlled by a $2^{nd}$ Thermostat installed at the outlet of cylinder block. The $2^{nd}$ thermostat closes when the coolant temperature is low. And this makes the coolant flow in cylinder block nearly stagnant, thereby reducing the coolant-side heat transfer coefficient and raising cylinder bore temperature. The $2^{nd}$ thermostat starts to open when the coolant temperature reaches a specified temperature. The test results on engine dynamometer show improved fuel economy and lower exhaust emission which result from the decrease in friction works and cooling loss. Also, several vehicle tests, with application of the new engine have been performed. Fuel economy improvement of 0.5{\sim}2.0%$ yields from different test modes and details are discussed in this paper.

• 한국생산제조학회지
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• 제21권4호
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• pp.601-607
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• 2012

The magnetic abrasive polishing (MAP), for online monitoring with AE sensor attachment, was performed in this study. To predict the surface roughness after the magnetic abrasive polishing of NAK80, the signal data acquired from the AE sensor were analyzed. A dimensionless coefficient, which consisted of average of AErms and standard deviation of AE signal, was defined as a characteristic of the MAP and a prediction model was obtained using least square method. A neural network, which had multiple input parameters from AE signals and polishing conditions, was applied for predicting the surface roughness. As a result of this study, it was seen that there was very close correlation between the AE signal and the surface roughness in the MAP. And then on-line prediction of the surface roughness after the MAP of the NAK80 was possible by the developed prediction model.

• 한국수산과학회지
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• 제44권4호
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• pp.383-389
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• 2011

The negative fishery factors from an environmental perspective are greenhouse gas emissions due to high fossil fuel use, destruction of underwater ecosystems by bottom trawls, a reduction in resources by fishing, and damage to ecosystem diversity. In particular, the greenhouse gas emissions from fisheries is an important issue based on the Cancun meeting in Mexico in 1992 and the Kyoto protocol in 2005. However, no investigations on the GHG emissions from Korean fisheries have been conducted. Therefore, a quantitative analysis of GHG emissions from the Korean fishery industry is needed as a first step to identify a method to reduce GHG emissions from fisheries. The purpose of this study was to investigate the degree of GHG emitted from fisheries. Here, we calculated the GHG emissions from four main Korean fisheries(i.e., large trawls, large purse seines, Danish seines, and bottom pair trawls) using the life cycle assessment(LCA) method. The system boundary and input parameters for each process level were defined for LCA analysis. The fuel use coefficient of each fishery was also calculated. The GHG emissions from edible seafood were calculated considering different consuming areas. The results will be helpful to understand GHG emissions from Korean fisheries.

• Transactions on Electrical and Electronic Materials
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• 제15권6호
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• pp.320-323
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• 2014

Ga-doped $LiFePO_4$ cathode materials were synthesized using a hydrothermal method. The microstructural characteristics and electrochemical performances were systematically investigated using field emission scanning electron microscopy, high-resolution X-ray diffraction, energy dispersive X-ray spectroscopy, charge-discharge cycling, cyclic voltammetry, and electrochemical impedance spectroscopy. Among the as-prepared samples, $LiFe_{0.96}Ga_{0.04}PO_4$ demonstrates the best electrochemical properties in terms of discharge capacity, electrochemical reversibility, and cycling performance with an initial discharge capacity of $125mAh\;g^{-1}$ and high lithium ion diffusion coefficient of $1.38{\times}10^{-14}cm^2s^{-1}$ (whereas for $LiFePO_4$, these were $113mAh\;g^{-1}$ and $8.09{\times}10^{-15}cm^2\;s^{-1}$, respectively). The improved electrochemical performance can be attributed to the facilitation of Li+ ion effective diffusion induced by $Ga^{3+}$ substitution.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전기물성,응용부문
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• pp.128-130
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• 2003

As toughness-investigation to improve brittleness of existing epoxy resin, elastic-factor of elastic epoxy using TMA (Thermomechanical Analysis), DMTA (Dynamic Mechanical Thermal Analysis) and FESEM (Field Emission Scanning Electron Microsope) for structure-images analysis were investigated. A range of measurement temperature of the TMA, DMTA was changed from -20[$^{\circ}C$] to 200[$^{\circ}C$]. When modifier was ratio of 0[phr], 20[phr], 35[phr], glass transition temperature (Tg) of elastic epoxy was measured through thermal analysis devices. Also, it was investigated thermal expansion coefficient ($\alpha$), modulus and loss factor through DMTA. In addition, it was analyzed structure through FSSEM and made sure elastic-factor of elastic epoxy visually. As thermal analysis results, 20[phr] was superior than 30[phr] thermally and mechanically. Specially, thermal expansion coefficient, modulus, damping properties were excellent. By structure-images analysis through FESEM, we found elastic-factor of elastic epoxy that is not existing epoxy, and proved high impact.

• Environmental Engineering Research
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• 제22권3호
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• pp.302-311
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• 2017

Nowadays, with the burgeoning development of economy, $CO_2$ emissions increase rapidly in China. It has become a common concern to seek effective methods to forecast $CO_2$ emissions and put forward the targeted reduction measures. This paper proposes a novel hybrid model combined principal component analysis (PCA) with regularized extreme learning machine (RELM) to make $CO_2$ emissions prediction based on the data from 1978 to 2014 in China. First eleven variables are selected on the basis of Pearson coefficient test. Partial autocorrelation function (PACF) is utilized to determine the lag phases of historical $CO_2$ emissions so as to improve the rationality of input selection. Then PCA is employed to reduce the dimensionality of the influential factors. Finally RELM is applied to forecast $CO_2$ emissions. According to the modeling results, the proposed model outperforms a single RELM model, extreme learning machine (ELM), back propagation neural network (BPNN), GM(1,1) and Logistic model in terms of errors. Moreover, it can be clearly seen that ELM-based approaches save more computing time than BPNN. Therefore the developed model is a promising technique in terms of forecasting accuracy and computing efficiency for $CO_2$ emission prediction.

• 한국수산과학회지
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• 제48권2호
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• pp.200-206
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• 2015

The fishing industry has a negative effect on the environment due to greenhouse gas (GHG) emissions with the high use of fossil fuels, the destruction of underwater ecosystems by bottom trawls, reduction in resources by fishing, and altered ecosystem diversity. GHG emissions from fisheries were discussed at the Canc$\acute{u}$n meeting in Mexico in 1992 and are part of the Kyoto protocol in 2005. However, few studies have investigated the GHG emissions from Korean fisheries. To find a way to reduce GHG emissions from fisheries, quantitative analysis of GHG emissions from the Korean fishery industry is needed. Therefore, this study investigated the GHG emissions from the Korean Danish seine fishery using the life cycle assessment (LCA) method. The system boundary and input parameters for each process level are defined for the LCA analysis. The fuel-use coefficient of the fishery is also calculated. The GHG emissions from the representative fish caught by the Danish seine fishery are considered and the GHG emissions for the edible weight of fishes are calculated, considering consumption in different areas and different slaughtering processes. The results will help to understand the GHG emissions from Korean fisheries.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
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• pp.296-301
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• 1999

Different papers such as toilet and towel tissue, newsprint and copy paper made from reclaimed fibres were characterized using UV-VIS reflectance and fluorescence spectroscopy. The emission properties of the extracts of the papers were also evaluated. Photochemical irradiation at ambient temperatures, and thermal aging of the copy papers at 105$^{\circ}C$ and 150$^{\circ}C$ were performed. Post-colour numbers (PC) were calculated from the reflectance values measured from the corresponding UV-VIS reflectance spectra. Light absorption coefficient spectra were calculated before and after irradiation, and the changes in absorption coefficient were related to the content of chromophores in the papers. Photochemical and thermal discolouration of the copy papers, similar to that of virgin fibres, was readily observed. The influence of changes in the concentrations of fluorescent brightening agents and dyes on the spectral properties was also assessed. Photostabilization studies of the copy papers were performed with the use of polymer additives polyethylene glycol (PEG) and polytetrahydrofuran (PTHF).