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        검색결과 21

        3.
        2017.05 구독 인증기관·개인회원 무료
        Graphene-based derivatives such as graphene oxide(GO) have great potential as membrane material due to their controllable d-spacing, extremely large surface area and tunability of multifunctional groups. GO, highly oxidized graphene, has especially good affinity to CO2 arose from its oxide functional groups(e.g. carboxylic acid, hydroxyl groups) on 2-D nanosheet plane. Here, we synthesized GO/polymer composite materials and fabricated large-area thin film composite(TFC) membrane for CO2 separation using polymeric porous support. Further, we have produced flat-sheet membrane modules with the TFC membranes and tested the performance of the module under CO2/N2 mixed gas and flue gas conditions. The membrane module exhibited high CO2 separation performance as 74% of purity and 22% of recovery under flue gas condition including CO2, O2 and N2.
        4.
        2016.11 구독 인증기관·개인회원 무료
        Graphene oxide (GO) has received a lot of attention in membrane science for its CO2-philic nature, which can facilitate CO2 separation performance. In addition, GO has attractive properties for gas separation membrane material due to thin-film membrane formation and tunable transport channel. GO membrane can be generally prepared by coating GO nanosheets on microporous polymer supports for mechanical stability. However, the substrates for in thin GO layer should be carefully chosen for good adhesion between GO layer and support surface with maintaining good separation performance. In this study, we tried to modify the surface properties of high permeable support membranes by using gutter layer as an intermediate layer, and measured the gas transport properties of these GO thin-film composite membranes.
        5.
        2016.11 구독 인증기관·개인회원 무료
        Graphene oxide (GO) can be used as a membrane material itself or a nanofiller to enhance gas separation performance of polymer membranes. Since GO has high CO2 affinity due to some polar groups, particularly GO membranes or GO/polymer membranes have been extensively studied for CO2 separation. Although ultrathin GO membranes show outstanding CO2 separation properties, the gas permeance through GO membranes is still low owing to high tortuosity caused by high aspect ratio of GO sheets. In this study, mixed-matrix membranes consisting of modified GO (as a dispersed phase) and high permeable polymer were prepared by combining each advantage of GO and high permeable polymer for improving gas separation performance. Both single-gas and mixed-gas permeation experiments were conducted with or without humidified feeds for post-combustion CO2 capture.
        6.
        2016.11 구독 인증기관·개인회원 무료
        Carbon nanomaterials such as graphene and its derivatives can be used for membrane applications due to its scalable area and one-atom-thickness, if pores or channels can be well-engineered. Particularly, graphene oxide (GO), a highly oxidized graphene sheet, shows promising membrane building block for gas separation as well as liquid separation. Due to its various polar groups, GO-based membranes also show good candidate for CO2 separation. In this regard, we tried to prepare large-scale GO-based, thin-film composite membrane for post-combustion CO2 capture, and also fabricated membrane modules (e.g., spiral wound membrane or plate-and-frame modules) to apply for real flue gas separation. In this study, the separation performance of two kinds of membrane modules will be compared in terms of gas permeance, selectivity, and pressure drop.
        7.
        2016.05 구독 인증기관·개인회원 무료
        Flat sheet membranes consisting of a selective layer and a porous support usually require gutter layer to reduce the bulk pores of the substrates. The gutter layer mitigates the geometric restrictions of support, which enables selective layer to have defect-free morphology with thin thickness (< 100 nm). For this reason, the gutter layer has been introduced to many industrial membranes, and the systematical studies of the effects of the gutter layer properties on membrane performance should be needed. Herein, we introduced several gutter layers with different thicknesses into graphene oxide intercalated polymer TFC membranes to determine the relationship between gutter layer properties and total membrane performances. This study provides more practical insight to determine the optimum gutter layer properties in designing TFC membranes.
        8.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to observe street fashion, to determine preferred design of jean and to analyze preferred jean styling based on types of jean pants design, toward 20s to 30s women. We observed outfits of jean styles on the street using photography method and conducted a survey to 400 females to get information of consumers. Four hundred questionnaires were analyzed using SPSS. As a result of street research, the majority of people were wearing jean pants with T-shirts, sandal/high heel shoes and totes. The results of market research showed that preferred jean styles were significantly associated with age and marital status. Preferred color of jean pants was also significantly associated with age variable. Current popular jean style was a skinny style. We evaluated results of styling with different jean pants, creating five different images. There was a significant relationship between age/marital status and styling image in different jean styles. In a bootcut style, age variable was significantly associated with different styling images. Generally, most of people responded cute/casual image styling was the best for the bootcut style. In skinny pants, there was a significant association between a residence area and a styling image. Modern/chic image styling with skinny pants was the most favored one. In cropped jean pants, marital status was significantly associated with styling image created. We realized that we can create different images through a styling.
        4,300원
        10.
        1995.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the removal of ammonium nitrogen by biological nitrification in raw water containing LAS using BAC. At batch teats, LAS removal by ozone followed the first order reaction, and the rate constants(k) by ozone dose 1, 3mg/min.L were $0.040min^{-1}$, $0.062min^{-1}$ respectively. Therefore, the more ozone was dosed, the higher LAS was removed The reaction between ozone and ammonium nitrogen also followed the first order, and rate constants(k) at pH7,8 and 9 were $8.9{\times}10^{-4}min-1$, $3.8{\times}10^{-3}min^{-1}$, and $2.9{\times}10^{-2}min^{-1}$ respectively at ozone dose of 3mg/min.L . Therefore, ammonium nitrogen was little removed by ozone under neutral pH of 7. The continuous flow apparatus had four sets composed of a ozone contacter and a GAC column. Through continuous filtration test for 50days, the following conclusions were derived; (1) LAS was removed 23%, 30% respectively by ozone dose 1, 3mg/L, and was not detected in all column effluents during the period of experiment. Therefore, it appeared that adsorption capacities of each column still remained. (2) Ammonium nitrogen concentration after ozone contact varied little in raw Water because pH of raw water was from 6 to 7, and was transfered to nitrite and nitrate within GAC columns as the result of staged nitrification. After 30days, nitrite was not detected in all column effluents due to biological equilbrium between nitro semonas and nitrobacter Average removals of ammonium nitrogen in each column after the lapse of 30days were the following; ${\cdot}$ column A (ozone dose 3mg/L, EBCT 9.5min): about 100% ${\cdot}$ column B (ozone dose 1mg/L, EBCT 9.5min): 91% ${\cdot}$ column C (ozone dose 3mg/L, EBCT 14.2min): about 100% ${\cdot}$ column D (ozone dose 0mg/L, EBCT 9.5min): 53% Though column A and C reached nitrification of about 100%, column C (longer EBCT than column A) was more stable than column A. (3) After backwash, nitrification reached steady state within 5 to 8 hours. Therefore, nitrification was not greatly affected by backwash. (4) According to the nitrification capacity in depth of column A, C, where 100% nitrification occured. LAS was removed within 20cm, while ammonium nitrogen required more depth to be removed by nitrification.
        4,200원
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