• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1998.05a
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• pp.221-228
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• 1998

2차원 노심핵설계 코드 HELIOS를 이용하여 $^{7}$ LiF-BeF$_2$-ThF$_4$-$^{233}$ UF$_4$ 용융염 핵연료와 흑연(Graphite) 감속재로 구성된 AMBIDEXTER(Advanced Molten-salt Break-even Inherently-safe Dual-mission EXperimental and TEst Reactor) 원자로의 육각주형 로심격자에 대해 핵적 자활성 요건의 설계해석을 수행하였다. AMBIDEXTER 원자로는 액체 핵연료의 유동성을 이용한 온라인 핵연료 정화ㆍ처리ㆍ재생의 연속공정을 도입하여 노내의 잔류 핵분열 생성물질의 포화양을 최소로 유지시키고 중성자 경제성을 극대화하므로 높은 전환율을 얻는 설계이다. 핵연료 내에 잔류하는 핵분열생성물질의 포화농도에 대응하는 연소도를 등가연소도로 정의할 때, 열출력 250MW$_{th}$ AMBIDEXTER 원자로의 등가연소도 374MWD/TeH.E.의 평형 로심 모델에 대해 핵적 자활성을 지배하는 주요 핵설계 인자로서 용융염 핵연료의 $^{233}$ U Mole 분율, 흑연-대-용융염의 체적비, 노심격자 간격 및 출력 밀도의 변화에 따른 임계도 및 전환율을 평가하였다. 그 결과, $^{233}$ U Mole 분율과 혹연-대-용융염 체적비를 좌표축으로 하는 2차원상공간에서 핵적 자활성 요건 상태함수는 각 노심격자간격에 대해 완만한 선형 함수로 표현할 수 있음을 확인하였다.

• Nuclear Engineering and Technology
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• v.12 no.2
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• pp.99-105
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• 1980

The distribution of $^{55}$ Mn and $^{38}$ Cl recoil species following radiative neutron capture in permanganates, chlorates and perchlorates has been investigated by using ion-exchange chromatography method. The whole of the $^{55}$ Mn radioactivity in permanganates appeared in two valence states, the $^{38}$ Cl radioactivity in chlorates in two valence states and also the $^{38}$ Cl radioactivity in perchlorates in three valence states. Recoil energy was calculated. The internal conversion of $^{38}$ Cl isomer transition affects the retention value. The greater the radii of the cation, the higher is the probability of the recoil atom breaking through the secondary cage. In ammonium salt, the ammonium ion behaves as a reducing agent. Crystal structures with their greater free space have shown low retention.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.31-31
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• 2011

Lanasol dyes containing ${\alpha}$-bromoacrylamide or ${\alpha},{\beta}$-dibromopropionylamide group are used for wool dyeing. They are normally applied to wool under pH 4.5 to 6.5 at $100^{\circ}C$. Although wool fabric can be dyed to obtain deep colour, high light and wet fastness, the dyeing processes need long dyeing time at high temperature, with salt addition, which inevitably causes environmental problems. Grafting is a modification method for textile where monomers are covalently bonded onto the polymer chain. It can be initiated by ozone, ${\gamma}$ rays, electron beams, plasma, corona discharge and UV irradiation. Coloration by UV-induced photografting exhibits several advantages such as fast reaction rate, energy saving, simple equipment, easy exploitation and environmentally friendliness. Also it requires much lower energy compared to the conventional dyeing and less damage to the substrate. In this study, a direct sequential UV-induced photografting onto wool fabrics was discussed. To understand the graft polymerization mechanism further, several characterization methods were used. Moreover, the effects of several principal factors on the graft photopolymerization were investigated. Furthermore, the colorfastness results were compared with conventional dyeing methods.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.2
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• pp.35-40
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• 2002

By the introduction of cleaning and drying processes, thermal extrusion system for the volume reduction of used polystyrene buoys was developed. It was tested in the costal area for the determination of operational reliability. By the removal of oyster shells and cleaning of salt, waste polystyrene buoys was changed to the raw material of plastics. The lower cost of one-tenth compared with that of the outer request treatment is promising the practical use of waste buoys' volume reduction system.

• Journal of Korean Society on Water Environment
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• v.30 no.3
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• pp.304-310
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• 2014

The conventional methods for total residual chlorine such as iodometry and DPD colorimetric can cause secondary pollution due to additional agents, also have a wide error range. As for alternative, electrochemical method can measure TRC(Total residual chlorine), and is not required as additional agents, also very suitable for using the fields of ballast water because test time is relatively fast. Therefore, this study was investigated for changing charge by agitation, salt concentration, and temperature change. Charge showed differences based on changes of reduction peak with or without agitation. In contrast, TRC and charge were well correlated in constant agitation speed. As TRC and charge were analyzed with high correlations in constant salinity and temperature of ocean, thereby conductivity was firstly measured, and charge had high correlation for TRC in spite of changing salinity and temperature Pt electrode revealed high reliability ($r^2=0.960$) because it was rarely effected by TRC, On the other hand, Au electrode appeared inadequate ($r^2=0.767$) to use sensor in less than 1.0 ppm of TRC. For high accuracy and detection of TRC, Pt and Au electrodes for test time were, respectively, 14 and 22 seconds. As a result, Pt electrode was more valuable than Au electrode in terms of response time.

• Atmosphere
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• v.30 no.1
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• pp.59-73
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• 2020

The characteristics of solar resources in South Korea were analyzed by comparing the solar irradiance derived from COMS (Communication, Ocean and Meteorological Satellite) with in-situ ground observation data (Pyranometer). Satellite-derived solar irradiance and in-situ observation showed general coincidence with correlation coefficient higher than 0.9, but the satellite observations tended to overestimate the radiation amount compared to the ground observations. Analysis of hourly and monthly irradiance showed that relatively large discrepancies between the satellite and ground observations exist after sunrise and during July~August period which were mainly attributed to uncertainties in the satellite retrieval such as large atmospheric optical thickness and cloud amount. But differences between the two observations did not show distinct diurnal or seasonal cycles. Analysis of regional characteristics of solar irradiance showed that differences between satellite and in-situ observations are relatively large in metrocity such as Seoul and coastal regions due to air pollution and sea salt aerosols which act to increase the uncertainty in the satellite retrieval. It was concluded that the satellite irradiance data can be used for assessment and prediction of solar energy resources overcoming the limitation of ground observations, although it still has various sources of uncertainty.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.55.1-55.1
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• 2011

Dye-sensitized solar cell(DSSC) have been considered one of the promising alternatives to conventional solar cells, because of their low cost, easy fabrication and relatively high energy conversion efficiency. However, although the cell offers reasonable efficiency at least 11%, the use of a liquid electrolyte placed technological challenges for achieving the desired durability and operational stability of the cell. In order to prevent or reduce electrolyte leakage considerable efforts have been made, such as p-type semiconductor or organic hole-transport material that better mechanical properties and simple fabrication processes. In this work, we synthesized solid-state electrolyte containing LiI and KI metal salt with starting materials of poly ethylene oxide to substitute liquid electrolyte enhance the ionic conductivity and solar conversion efficiency. Li+ leads to faster diffusion and higher efficiency and K+ leading to higher ionic conductivity. The efficiency of poly ethylene oxide/LiI system electrolyte is 1.47% and poly ethylene oxide/potassium electrolyte is 1.21%. An efficiency of 3.24% is achieved using solid-state electrolyte containing LiI and KI concentrations. The increased solar conversion efficiency is attributed to decreased crystallinity in the polymer that leads to enhanced charge transfer.

• Nuclear Engineering and Technology
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• v.30 no.3
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• pp.245-261
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• 1998

In order to validate the variable aperture channel model that can deal with the non-uniform How rate in flow domain, migration experiments of conservative tracer were performed in two artificial fractures, a parallel and a wedge-shaped fracture. These different fracture shapes were designed to give different flow pattern. The fractures were made from a transparent acrylic plastic plate and a granite slab with dimensions of 10 $\times$ 61 $\times$ 61 cm. Uranine (Fluorescein sodium salt) was used as a conservative tracer. The volumetric flow rates of uranine feed solution were 30 mL/ hr, giving a mean residence time in the fracture of approximately 24 hours for the parallel fracture and 34 hours for the wedge-shaped fracture. The migration plumes of uranine were photographed to obtain profiles in space and time for movement of a tracer in fractures. The photographed migration plume was greatly affected by the geometric shape of fractures. The variable aperture channel model could have predicted the experimental results for the parallel fracture with a large accuracy. It is expected that the variable aperture channel model would be effective to predict the transport of the contaminant, especially, with the flow rate variation in a fracture.

• Journal of Korean Society of Water and Wastewater
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• v.31 no.4
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• pp.339-346
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• 2017

In this study, thermal performance test of VMD module was performed, prior to the construction of the demonstration plant using the vacuum membrane distillation (VMD) module of the capacity of $400m^3/day$ and to the commercialization of the VMD module. For the thermal performance test, the experimental equipment of capacity of $2m^3/day$ was constructed. The permeate flux test and thermal performance test according to feed water conditions such as temperature and flow rate were conducted. The VMD module used in the study was manufactured by ECONITY Co., LTD with PVDF hollow fiber membrane. As a result, the Performance Ratio (PR) of the VMD module showed the maximum value of 0.904 under the condition of feed water temperature of $75^{\circ}C$ and flow rate of $8m^3/h$. PR value of the VMD module using PVDF hollow fiber membrane showed linearly increasing relationship with feed water temperature and flow rate. Also, The permeate flux of the VMD module was analyzed to have maximum value of 18.25 LMH and the salt rejection was 99.99%.

• Membrane Journal
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• v.30 no.2
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• pp.111-123
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• 2020

Growing industrialization and climate change lead to the huge demand for clean drinking water. Desalination of sea water by membrane separation process is one of the alternative and economically viable methods to fulfil the demand for water. In the membrane separation process, the presence of 2D materials enhances the performance of membrane by facilitating the water permeation, salt rejection, flux rate, and selectivity compared to the traditional reverse osmosis thin-film-composite membranes. In this review, composite membranes with different kinds of 2D materials are discussed on the basis of materials synthesis, characterization and desalination process.