• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.309-312
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• 2005

Admixture compounds for shortening setting time and accelerating early strength development of EVA polymer powder-modified mortars were made by mixing various quick setting agents. As a result, the quick setting agents contribute to strength development of the mortars in the early curing age of 168h or less. In the viewpoint of early strength development of EVA polymer powder-modified mortars, an quick setting agent content of 20$\%$ is recommended. Early strength of EVA polymer powder-modified mortars expresses the excellent strength with 5$\%$, 10$\%$ of rates of polymer mixing. The rate of polymer mixing was able to be adjusted and flexural strength which is a predeterminded initial strength was also able to satisfy 3MPa(s).

• 한국CDE학회논문집
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• 제4권3호
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• pp.210-223
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• 1999

An efficient management of product information is critical to the enhancement of corporate competitiveness. Product information is often distributed in term of organization, geography, and time. With the rapid increase in the use of Internet or its associated Web and intranets, it has been accelerating to integrate the distributed information. In this research, a Distributed, Open, Intelligent Product data Management system, namely DOI-PDM, is developed. This system deals with product information following the STEP standard, and its operation is controlled by a Web-based workflow management system. CORBA is employed to ensure interoperability among distributed objects. It is intended to achieve openness by using various standards, such s STEP, KQML, SGML, and WfMC specifications. One major difficulty in managing it needs also be properly modified according to the dynamics. It however is very hard to have a prior anticipation to the dynamics. It however is very hard to have a prior anticipation to the modification requirements in practice. We introduce a process adaptation model and a use of intelligent agent technology. An agent is delegated to modify process definitions during run-time. A method of agent implementation and a proper communication scheme among te agents are proposed. Also developed in this research is a STEP-based content search system which can co-work with the agents by providing relevant product information that the agents require.

• 한국미생물·생명공학회지
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• 제39권3호
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• pp.301-307
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• 2011

유류로 오염된 토양을 토양미생물 복원제를 첨가한 후 다양한 조건에서20일 동안의 유류저감효과를 알아보았다. 실험조건은 유류로만 오염된 토양(DS), 토양미생물 복원제를 20%(w/w)가 되도록 첨가한 유류로 오염된 토양(DSP), 토양 미생물 복원제를 넣은 후 pH를 중성으로 보정한 유류로 오염된 토양(DSP-1), 토양미생물 복원제와 촉진제를 넣은 유류로 오염된 토양(DSP-2), 토양미생물 복원제와 촉진제를 넣은 후 pH를 중성으로 보정한 유류로 오염된 토양(DSP-3)을 설정하였다. 실험 결과 pH를 보정한 토양미생물 복원제를 첨가한 유류오염토양은 탈수소 효소 활성과 TPH 저감에서의 효능이 우수하였다. 실험이10일 경과되었을 때 탈수소 효소 활성이 가장 높은 DSP-1 토양이 TPH 역시 가장 활발히 분해했다. 결과적으로 초기 10일의 배양기간 동안 토양미생물 복원제를 첨가한 토양은 대조군에 비해 38% 가량의 TPH 저감상승효과를 볼 수 있다. 토양미생물 복원제의 첨가를 통해 초기 저감속도를 올려줄 수 있으며, 최종적으로도 비 첨가군에 비해 높은 저감효율을 기대할 수 있다. 토양미생물 복원제를 유류오염토양을 복원한다면 초기 오염물질을 빠르게 처리할 수 있지만 미생물 활성은 pH, 온도 등 환경 인자에 많은 영향을 받으므로 토양미생물 복원제의 효율을 최대화하기 위해서는 환경 인자를 분석하여 이를 바탕으로 복원을 진행한다면 오염물질 정화 효율을 향상시킬 수 있을 것이다.

• 한국식품영양과학회지
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• 제27권2호
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• pp.201-206
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• 1998

The antibrowning effcts of cysteine, citric acid and ascorbic acid on the browning reaction of enzymatic garlic hydrolyzate were investigated at 37$^{\circ}C$ for 12 days. Cysteine was the most effective antibrowning agent followed by citric acid. The antibrowning effects of cysteine and citric acid were greater as concentrations increased, and the optimal concentration of both cysteine and citric acid as antibrowning agents was 0.3%. Ascorbic acid itself contributed to the browning reaction and showed an accelerating effect as the concentration increased. The addition of 0.1% ascorbic acid as synergist either to 0.3% cysteine or 0.3% citric acid did not enhance significantly the antibrowning effect of cysteine or citric acid. When stored at 3$0^{\circ}C$, 4$0^{\circ}C$ and 5$0^{\circ}C$, the browning reaction was accelerated as the temperature increased, especially at 5$0^{\circ}C$. Even though the effects of citric acid and cysteine as inhibitors on the browning reaction decreased as temperature increased, cysteine was more effective in decreasing browning reaction than citric acid.

• 한국물환경학회지
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• 제26권4호
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• pp.687-690
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• 2010

The objective of this study is to investigate the effect of aldehyde compounds and ploysulfide as accelerating agents on removal of heavy metals and CN in plating wastewater. As a results of the experiments, the removal efficiency of cyanide using the formaldehyde type of aldehydes was the highest at pH 9. Next types were sodium formaldehyde bisulfite addut> paraldehyde> paraformaldehyde. Also, optimum pH and dosage for treating the residual heavy metals by using polysulfide were pH 9 and 30 mg/L, respectively. The removal efficiencies of cyanide, chromium, zinc and copper were above 96.7% at optimum condition.

• 한국시스템다이내믹스연구
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• 제5권1호
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• pp.5-33
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• 2004

This study explores how agents would make decisions responding to control mechanism in contractual relationship of their firm. Focusing on agent's averse behavior against control, system dynamics model for agent's opportunistic behavior is developed in view of agent theory and control theory. This SD model shows that control mechanism by contracts doesn't always play a positive role on corporate decision-making process and Control, especially in the over-controlled contracts, often makes a paradox accelerating agent's opportunistic behavior unexpectedly. This paradox provides us both theoretical and practical implications for the relationship between control mechanism and autonomous behavior for sustainable corporate management.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.673-676
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• 2006

Steel FibreReinforced Shotcrete(SFRS) is one of the main tunnel support along with the rock bolt during the excavation and after the completion of the tunnel. In the standard qualification of the SFRS defined by Korea Highway Corporation, 28 day core specimen has to meet the compressive strength of 19.6 MPa and over 90 % fibre contents. Furthermore, for the 28 days brick shaped specimen made by shooting, flexural strength should be over 4.4 MPa and flexural toughness ratio which can be calculated from flexural toughness factor has to meet more than 68% of flexural strength. In shotcrete, accelerating agent is added for the rapid strength development. Silicate and aluminate type agents are known to develop shotcrete strength rapidly, however, has such problem to degrade the middle and long term strength. Hence, using poly carboxylic super plasticizer, it was aimed to enhance the quality of the shotcrete with the lower water-cement ratio and the same level of workability. The present paper shows the part of the field test result and its analysis.

• 한국구조물진단유지관리공학회 논문집
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• 제16권4호
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• pp.122-129
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• 2012

이 연구에서는 시멘트계 광물로 제조된 그라우트의 사용에 의해 발생되는 환경문제인 pH의 증가와 중금속오염을 MC계와 킬레이트고분자를 이용하여 평가하고자 하였다. 그라우트 재료로 보통포틀랜드시멘트와 슬래그시멘트를 사용하였고 급결재로 칼슘알루미네이트계 급결성재료의 혼합물을 사용하였으며, 중금속과 pH의 발생을 방지하기 위해 증점제를 사용하였다. 측정결과, 킬레이트고분자를 사용할 경우에 그라우트에 의한 pH의 증가가 최소화되었으며 중금속($Cr^{6+}$)은 용출되지 않았다. 그 이외의 경우에는 pH의 증가와 중금속 용출이 뚜렷이 증가하였다. 또한, 재령에 따른 중금속 발생량은 용출시험 1일에서 전 용출량의 약 97% 이상이 용출되었고 이후는 추가 발생되지 않는 것으로 나타났다. 이 연구의 결과로부터 pH의 증가와 $Cr^{6+}$과 같은 중금속의 용출을 제어하기 위해서 BSC와 킬레이트고분자를 사용하는 것이 아주 유용함을 알 수 있었다.

• Steel and Composite Structures
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• 제21권4호
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• pp.921-947
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• 2016

Concrete Filled Fibre Reinforced Polymer Tube (CFFT) for new columns construction has attracted significant research attention in recent years. The CFFT acts as a formwork for new columns and a barrier to corrosion accelerating agents. It significantly increases both the strength capacity (Strength enhancement ratio) and the ductility (Strain enhancement ratio) of reinforced concrete columns. In this study, based on predefined selection criteria, experimental investigation results of 134 circular CFFT columns under axial compression have been compiled and analysed from 599 CFFT specimens available in the literature. It has been observed that actual confinement ratio (expressed as a function of material properties of fibres, diameter of CFFT and compressive strength of concrete) has significant influence on the strength and ductility of circular CFFT columns. Design oriented models have been proposed to compute the strength and strain enhancement ratios of circular CFFT columns. The proposed strength and strain enhancement ratio models have significantly reduced Average Absolute Error (AAE), Mean Square Error (MSE), Relative Standard Error of Estimate (RSEE) and Standard Deviation (SD) as compared to other available strength and strain enhancement ratios of circular CFFT column models. The predictions of the proposed strength and strain enhancement ratio models match well with the experimental strength and strain enhancement ratios investigation results in the compiled database.

• 한국응용과학기술학회지
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• 제11권2호
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• pp.139-146
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• 1994

MDABM and MDAEW, as a accelerating weight loss agents, were prepared by adding water to myristyldimethylbenzylammonium bromide(MDAB) and myristyldimethylethylammonium ethyl sulfate (MDAE) synthesized. As a result of weight loss finishing of the MDABW and MDAEW with NaOH on PET fiber, the ratio of weight loss of MDABW was very larger than that of MDAEW. This result showed that quaternary ammonium bromide had higher weight loss effect than quaternary ammonium sulfate, and the ratio of weight loss was greatly varied with the kind of quaternary ammonium salts used. In these conditions, proper treatment concentration, treatment time, and treatment bath ratio were about 8g/l, $6O{\sim}90min$, and $40:1{\sim}50:1$, respectively.