• Title/Summary/Keyword: 화제화

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A Fundamental Study on the Superplasticized Concrete (유동화(流動化)콘크리트에 관한 기초연구(基礎研究))

  • Moon, Han Young
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.2 no.2
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    • pp.47-59
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    • 1982
  • It is well practised in the field of concrete engineering that the effort of improving the low slumped concrete and uplifting the quality of the soft concrete by adopting the superplasticizer. In this paper, an attempt is made to find out the optimum mix design of the superplasticized concrete with an unit weight of cement 400 kg and the range of $19{\pm}1cm$ of slump by variatlng the sand percentage, unit water content and the dosage of superplasticizer. As a result, the author obtained the basic idea on the optimum mix design and strength of superplasticized concrete. On the other hand, it is also considered during the research the method of preventing the slump loss of the superplasticized concrete due to the delayed time after concrete mixing.

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Fabrication of lightweight geopolymer based on the IGCC slag (IGCC 용융 슬래그를 이용한 경량 지오폴리머 제조)

  • Park, Soo-bin;Kim, Kang-duk;Kang, Seung-gu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.27 no.6
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    • pp.319-326
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    • 2017
  • In this study, a lightweight geopolymer was prepared using by slag discharged from IGCC (Integrated Gasification Combined Cycle) power plant and its physical properties, the density and compressive strength, were analyzed as a function of the concentration of alkali activators, W/S ratio and aging times. Also the possibility of applying it to lightweight materials by adding Si sludge as a foaming agent to the geopolymerg was investigated. In particular, a complex composition of alkali activator and a pre-curing process were applied to improve the strength properties of lightweight geopolymers. While the compressive strength of the lightweight geopolymer using a single activator was 9.5 MPa, the specimen made with a complex composition of alkali activator had compressive strength of 2~5 times higher. In addition, the lightweight geopolymer with pre-curing process showed a compressive strength value of 18~48 % higher than that of specimen made with no precuring process. In this study, by using a complex activator and a pre-curing process. the maximum compressive strength of lightweight geopolymer was obtained as 40 MPa (The specimen was aged for 3 days and had density of $1.83g/cm^3$), which is comparable to cement concrete. By analyzing the crystal phase and microstructure of geopolymers obtained in this study using by XRD and SEM, respectively, it was confirmed that the flower-bud-like zeolite crystal was homogeneously distributed on the surface of the C-S-H gel (sodium silicate hydrate gel) in the geopolymer.

Immobilization of Pb-contaminated Soils using Phosphate (인산염을 이용한 납오염 토양의 고정화)

  • 박준형;곽문용;신원식
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2004.09a
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    • pp.252-257
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    • 2004
  • 본 연구에서는 인산염을 이용여 납으로 오염된 Clay 사격장과 인위적으로 오염시킨 자연토양의 중금속의 고정화 실험을 수행하였다. 인산염 고정화제로는 DAP (diammonium phosphate)를 사용하였다. DAP를 투입한 중금속 오염토양을 고정화 실험과 TCLP로 용출 하였을 때, 99% 정도 고정화되었다. 인산염 투여양이 증가할수록 고정화 효율은 증가하는 것으로 나타났으며, 최적 인투입량은 128 mmol as P/kg인 것으로 나타났다. DAP 투입양이 증가할수록 토양의 pH는 증가하는 것으로 나타났으며, 토양의 초기 pH 변화에 따라 고정화 효율은 크게 변하지 않은 것으로 나타났으나, pH가 높을수록 고정화 효율은 작은폭으로 증가하는 것으로 나타났다.

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Photochemical Synthesis of Aspartylphenylalanyl Methyl Ester (광 알킬화 반응에 의한 Aspartylphenylalanyl Methyl Ester의 합성)

  • Sang Chul Shim;Kyu Ho Chae
    • Journal of the Korean Chemical Society
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    • v.19 no.5
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    • pp.367-374
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    • 1975
  • Glycine residue in N-X-glycylphenylalanine methyl ester(X = trifluoroacetyl or acetyl) was converted into aspartic acid derivative by a photoalkylation reaction. The reaction was induced with 350 nm lamp using a combination of diacetyl/di-t-butyl peroxide (DBP) as the photoinitiator, and acetic anhydride as the alkylating agent. In the thermal reaction with DBP and acetic anhydride, the same alkylation reaction of the dipeptide was observed. From this thermal alkylation reaction the photoalkylation reaction is also thought to undergo via free radical mechanism.

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Preparation of Sulfonated Polysulfone Membranes (Sulfonated Polysulfone막의 제조 및 투과특성)

  • 김윤조;전종영;구성회;탁태문
    • Membrane Journal
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    • v.6 no.1
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    • pp.10-21
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    • 1996
  • This study is undertaken to investigate the major factor which causes a fouling phenomenon in membrane separation system and effect of hydrophilic treatment on fouling repression of hydrophobic polymer (polysulfone, PSf). Chlorosulfonic acid (CSA) and sulfuric acid as a sulfonating agents are used to produce sulfonated PSf (SPSf). SPSf membrane is prepared under several conditions to investigate it's separation process. The extent of fouling-repression is measured by membrane filtration index (MFI) value. With increasing the ion exchange capacity (I.E.C), the flux of SPSf membrane is decreased but the rejection is increased and the flux is less reduced. According to the MFI value, the SPSf membrane has a fouling-retardant effect.

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Effects of Compatibilizer and Graphene Oxide on the Impact Strength of PC/ABS Blend (PC/ABS의 충격강도에 미치는 상용화제와 그래핀 옥사이드의 영향)

  • Park, Ju Young;Lee, Bom Yi;Cha, Hye Jin;Kim, Youn Cheol
    • Applied Chemistry for Engineering
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    • v.26 no.2
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    • pp.173-177
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    • 2015
  • In this study, effects of both the grafted ABS-g-MAH and the added graphene oxide (GO) on the impact strength of polycarbonate (PC)/poly(acrylonitrile-butadiene-styrene) (ABS) blends were discussed. The PC/ABS blends and PC/ABS/GO composites were fabricated by using twin screw extruder with ABS-g-MAH as a compatibilizer. The ABS-g-MAH was prepared by melting extrusion of ABS and maleic anhydride (MAH) with DCP (dicumyl peroxide) as an initiator using twin screw extruder and the synthesis of ABS-g-MAH was confirmed by the presence of carbonyl group (C=O) peak at $1780cm^{-1}$ of FT-IR spectrum. According to the thermal, rheological, and impact properties of PC/ABS blends, 5 phr (parts per hundred resin) of compatibilizer was chosen as an optimum content for the PC/ABS/GO composites. It was observed that the thermal decomposition of ABS/PC/GO composites increased with GO contents, but there was no significant changes or a decrease in the impact strength. Also the composite fabricated by ABS/GO showed small increase in the impact strength. From the result of the dynamic rheometer to observe the processing properties, the complex viscosities of PC/ABS blend including the compatibilizer increased, but the complex viscosities of composites added GO were not changed.

Effect of Phase Stabilizers on the Phase Formation and Sintering Density of $Na^+$-Beta-Alumina Solid Electrolyte (상 안정화제가 $Na^+$-Beta-Alumina 고체 전해질의 상 형성 및 소결밀도에 미치는 영향)

  • Lee, Ki-Moon;Lee, Sung-Tae;Lee, Dae-Han;Lee, Sang-Min;Lim, Sung-Ki
    • Applied Chemistry for Engineering
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    • v.23 no.6
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    • pp.534-538
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    • 2012
  • $Na^+$-beta-alumina solid electrolyte was synthesized by solid state reaction using $Li_2O$ and MgO as a phase stabilizer, and the effect of stabilizers on the phase formation and sintering density was investigated. In order to determine the phase fraction according to the synthesizing temperature, the molar ratio of [$Na_2O$] : [$Al_2O_3$] was fixed at 1 : 5, and calcination was conducted at temperatures between $1200{\sim}1500^{\circ}C$ for 2 h. In the $Li_2O$-$Na_2O$-$Al_2O_3$ ternary system, ${\beta}^{{\prime}{\prime}}$-alumina phase fraction considerably increased by the secondary phase transition at $1500^{\circ}C$, whereas it maintained similarly in the MgO-$Na_2O$-$Al_2O_3$ system. Additionally, the disc-type specimens of $Na^+$-beta-alumina were sintered at the temperature between $1550{\sim}1650^{\circ}C$ for 30 min, and relative sintering densities, phase changes, and microstructures were analyzed. In case of $Li_2O$-stabilized $Na^+$-beta-alumina, ${\beta}^{{\prime}{\prime}}$-phase fraction and relative density of specimen sintered at $1600^{\circ}C$ were 94.7% and 98%, respectively. Relative density of MgO-stabilized $Na^+$-beta-alumina increased with a rise in sintering temperature.

A Study on the Development of Eco-friendly Materials Using EPDM Scrap : Functionalization of EPDM and PP (에틸렌-프로필렌 고무 스크랩을 이용한 친환경소재 개발에 관한 연구 : EPDM과 PP의 기능화)

  • Kim, Sub;Chung, Kyung-Ho
    • Clean Technology
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    • v.15 no.3
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    • pp.180-185
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    • 2009
  • The ethylene-propylene rubber (EPDM) scrap generated from automobile weatherstrip manufacturing process was used to make a thermoplastic elastomer through blending with polypropylene. The surface activated EPDM powder was obtained by the high temperature and shear pulverizer. The addition of surfactant resulted in more surface activated EPDM powder and the optimum loading amounts of surfactant was 1.5 phr. Maleic anhydride was grafted onto polypropylene by reactive blending to give functionalized polypropylene. The wetting property between EPDM scrap and polypropylene was improved by the addition of poly (ethylene-co-acrylic acid) as a compatibilizing agent. Poly(ethylene-co-acrylic acid) decreased the surface tension of polypropylene and thus would contribute to the wettability with EPDM powder.

Properties of non-cement mortars with small addition of alkali activator using fly ash and fused waste slag (석탄회 및 용융폐기물 슬래그에 소량의 알칼리 활성화제를 첨가한 무시멘트 모르타르의 특성)

  • Kim, Yootaek;Lee, Kyongwoo
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.25 no.6
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    • pp.257-262
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    • 2015
  • Recently the world wide efforts reduce occurrence of $CO_2$; global warming main reason. The aim of this study is to improve recycling rate of the fly ash (FA) and fused waste slag (FWS) from the power plant and to carbonate under supercritical condition ($40^{\circ}C$, $80kgf/cm^2$ pressure, 60 min) for $CO_2$ fixation. Specimens of mortar with various mixing ratios of FA, FWS (from 100:0 to 20:80 in 5 steps of 20 % reduction each time), distilled water and 3 M NaOH alkali activators were prepared. As a result, the proportion of weight change ratio increases with CaO content, to 12 % after carbonation under the supercritical condition. There is difference of compressive strength between the carbonated and the alkali activator mortar specimens. The stabilization of $CO_2$ fixation through carbonation which could confirm the applicability of the eco-friendly materials without loss of compressive strength.

신규항암제 DA-125의 액상 안정화

  • 박양환;박광신;권종원;차봉진;정비환;정기화
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1994.04a
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    • pp.309-309
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    • 1994
  • DA-125에 당류로서 Inositol, Dextrose, Iactose, Mannitol 및 Sorbitol을 첨가하여 DA-125 단독으로 용해한 시료와 비교 평가하였을 때 DA-125의 안정성에 큰 영향이 없었으며, 아미노산 중 L-lysine첨가시 안정성이 향상되는 컷으로 나타났다. 염류를 사용하였을 때는 NaCl, MgSO$_4$첨가시 안정성이 크게 증가하였으며, NaCl의 첨가 농도에 따른 안정성을 시험한 결과 NaCl의 농도 증가에 따라 DA-125의 안정성이 증가하는 것으로 나타났다. 또한 기타 안정화제로 Sodium Bisulfite 첨가시 안정성이 증가되었다. 안정성 시험 중 pH및 용액상태는 변화하지 않았다.

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