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        검색결과 8

        2.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The CDI (Capacitive deionization) is one of the desalination technologies that use a carbon material electrode with large surface area and excellent electrical conductivity. Recently, research on a MCDI (Membrane Capacitive deionization) process, which is a combination of an ion-exchange membrane, has been actively conducted. In this study, we tried to find out the water quality of treated water and the concentration characteristics of concentrated water through TDS analysis by MCDI conventional and circulation process. In producing treated water, there was no significant difference in adsorption efficiency between MCDI conventional and circulation process. It was confirmed that both processes adsobed more than 96 %. However, the MCDI conventional process showed a low yield of 50 %, whereas the MCDI circulation process showed a high yield of 97.6 %. It's because, the wasted water was reused at desorption. In the case of the TDS concentration using MCDI circulation process, as the cycle progressed, the TDS concentration was concentrated up to 1,300 mg/L, but the rate gradually decreased. It is believed that this is because the volume of the concentrated water tank is limited, and the amount of soluble ions gradually decreases. As a result of analyzing the wasted water at MCDI circulation process through Ion Chromatography, it was confirmed that the concentration of all ions were concentrated. However, there was no significant difference in the types and proportions of analyzed ions. It is judged that the types and concentration of ions do not have a significant effect on adsorption and desorption in the MCDI circulation process.
        4,000원
        3.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Recently, various researches have been studied, such as water treatment, water reuse, and seawater desalination using CDI (Capacitive deionization) technology. Also, applications like MCDI (Membrane capacitive deionization), FCDI (Flow-capacitive deionization), and hybrid CDI have been actively studied. This study tried to investigate various factors by an experiment on the TDS (Total dissolved solids) removal characteristics using MCDI module in aqueous solution. As a result of the TDS concentration of feed water from 500 to 2,000 mg/L, the MCDI cell broke through faster when the higher TDS concentration. In the case of TDS concentration according to the various flow rate, 100 mL/min was stable. In addition, there was no significant difference in the desorption efficiency according to the TDS concentration and method of backwash water used for desorption. As a result of using concentrated water for desorption, stable adsorption efficiency was shown. In the case of the MCDI module, the ions of the bulk solution which is escaped from the MCDI cell to the spacer during the desorption process are more important than the concentration of ions during desorption. Therefore, the MCDI process can get a larger amount of treated water than the CDI process. Also, prepare a plan that can be operated insensitive to the TDS concentration of backwash water for desorption.
        4,000원
        4.
        2009.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The effects of Quenching and Partitioning (Q&P) and Annealed Martensite (AM) heat treatment on the microstructure and tensile properties were investigated for 0.24C-0.5Si-1.5Mn-1Al steels. The Q&P steels were annealed at a single phase (γ) or a dual phase (γ+α), followed by quenching to a temperature between Ms and Mf. Then, enriching carbon was conducted to stabilize the austenite through the partitioning, followed by water quenching. The AM steels were intercritically annealed at a dual phase (γ+α) temperature and austempered at Ms and Ms±50˚C, followed by cooling in oil quenching. The dual phase Q&P steels showed lower tensile strength and yieldyield strength than those of the single phase Q&P steels, and tThe elongation for the dual phase Q&P steel was partitioning 100s higher than that of that for the single phase Q&P steels as the partitioning time was less than 100s up to partitioning 100s. For AM steels, the tensile/yield strength decreased and the total elongation increased as the austempering temperature increased. The stability of the retained austenite controlled the elongation for Q&P steels and the volume fraction of the retained austenite controlled the elongation for AM steels.
        4,000원
        5.
        2011.12 KCI 등재 서비스 종료(열람 제한)
        Emission reduction program for in-use diesel vehicles(ERPDV) has been enacted since 2004 over the Seoul metropolitan area, and diesel emission reduction is forced to fulfill this regulation. This study was performed to evaluate the ERPDV using PM10 concentrations of both road-side monitoring and national background network during the period of 2004-2010. In order to assess the pure road emission, we first eliminated the long range transport effect by deducting the trend of annual national background concentrations from the road-side PM10 concentrations, and then analyzed the time series of the resultant PM10 concentrations over Seoul metropolitan area. The annual rates of variations of road-side PM10 with the deduction of trend of background level show -3.2, +0.4, and -2.4㎍/㎥/year, in Seoul, Incheon, and Gyonggi province, respectively. There are steadily decreasing trend in Seoul with all of statistic parameters such as mean, mediam, 5%ile, 10%ile, 25%ile, 75%ile, 90%ile, and 95%ile concentrations. Incheon shows some fluctuations with positive with no significant trend, and Gyonggi province shows overall decreasing but not consistent. Student-t test shows 95% significant level of ERPDV effect in Seoul, but there exists no significant level greater than 90% in both Incheon, and Kyonggi province. Total annual averaged trend over the whole Seoul metropolitan area is estimated to lie in approximately -2.9㎍/㎥/year in this study, implying the intimate involvement of ERPDV to a large extent. This is also suggesting that the further research cost-effectiveness of ERPDV with consideration of the long range transport process would be needed over the Seoul metropolitan area.