• 한국응용과학기술학회지
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• 제7권2호
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• pp.11-18
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• 1990

N-alkyl carboxy pyridinium chlorides such as N-lauryl carboxy-pyridinium chloride, N-myristyl carboxy pyridinium chloride, N-cetyl carboxy pyridinium chloride and N-stearyl carboxy pyridinium chloride were synthesized by the reaction of nicotinic acid and isonicotinic acid with long chain alkyl chlorides, and N-alkyl pyrinium carboxylates such as N-lauryl pyridinium carboxylate, N-myristyl pyridinium carboxylate. N-cetyl pyridinium carboxylate and N-stearyl pyridinium carboxylate were prepared from N-alkyl carboxy pyridinium chlorides. These reaction products could be separated by both column chromatogrphy, and paper chromatography, and there dissociation constants of N-alkyl pyridinium carboxylates were found to pKa $1.0{\times}10^{13}{\sim}6,31{\times}10^{14}$.

• 한국표면공학회지
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• 제40권1호
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• pp.16-22
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• 2007

Recently, mesoporous metallic materials are becoming more and more important in various applications like catalysts, electrochemical detectors, batteries, and fuel cells because of their high surface area. Among the various methods for manufacturing mesoporous structure, surfactant templating method followed by electroplating has been tried in this study. A mesoporous metallic film was prepared by electrodeposition from electroplating solution mixed with surfactant template. Nonionic type lyotropic liquid crystalline surfactant, Brij56, and nickel acetate based solution were selected as a template material and electroplating solution, respectively. To determine the content of surfactant forming a hexagonal column structure, the phase diagram of electroplating solution and surfactant mixture has been exploited by polarized optical microscopy equipped with heating and cooling stage. Nickel films were electroplated on Cu foil by stepwise potential input method to alleviate the concentration polarization occurred during the electroplating process. TEM and XRD analyses were performed to characterize the size and shape of mesostructures in manufactured nickel films, and electrochemical characterization was also carried out using cyclic voltammetry.

• 대한안전경영과학회지
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• 제13권4호
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• pp.213-223
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• 2011

Recent cross-country competition and Chinese steel industry because of the emerging steel industry in Korea is a very difficult situation. Therefore, the steel industry in order to overcome this difficult market environment, the quality, cost competitiveness, enhance customer service levels and enhance international competitiveness through is needed. In this study, the purpose of strengthening the competitiveness of steel companies in order and hit the recovery of raw materials have been developed to optimize the model, developed before and after the results were analyzed. In addition, when applied to other products in order to minimize risk and optimize cutting trial stage of development details of the model is presented in detail. Therefore, the developed model was applied to order the recovery of raw materials hits and significantly improved production planning time has been shortened dramatically. In the present study the contents of other products when properly applied and the competitiveness of companies to improve customer service levels are expected to be helpful.

• 한국구조물진단유지관리공학회 논문집
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• 제25권4호
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• pp.12-19
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• 2021

최근 전 세계적으로 지진이 빈번하게 발생하면서 지진으로부터 철근콘크리트 시설물의 내진설계 및 내진보강에 대한 연구가 활발히 진행되고 있다. 특히 철근콘크리트 구조물의 압축부재인 기둥은 지진에 의한 횡력에 취약하여, 적절한 내진보강공법이 필요하다. 따라서 본 연구에서는 시공이 빠르고 간편한 벨크로 내진보강재를 개발하고자 하였다. 벨크로 내진보강재 개발을 위해 기존 공업용 벨크로의 부착성능과 인장력을 증가시켰으며, 공업용 벨크로와 개발된 벨크로 내진보강재의 인장성능을 비교하기 위해 직접인장실험을 수행하였다. 또한 공업용 벨크로와 벨크로 보강재로 보강된 RC 기둥의 내진성능을 예측하기 위한 해석연구를 수행하였다. 해석결과를 바탕으로 비내진 RC 기둥의 벨크로 보강재의 보강에 따른 강도와 연성능력에 대하여 검토하였다. 해석결과 공업용 벨크로와 벨크로 보강재로 보강된 비내진 RC기둥의 강도와 연성능력이 모두 증가함을 확인하였으며, 개발된 벨크로 내진보강재의 내진 성능이 공업용 벨크로 보다 크게 나타남을 확인하였다.

• 산업기술연구
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• 제20권A호
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• pp.269-278
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• 2000

The pressure-time profile of the explosion gases can controlled for the use of cartridge explosive with two techniques known as Decoupling and spacing of the charges. Decoupling consists of a space between the explosive column and wall of the blast hole. Four different decoupling index 1.4, 1.8, 2.34, 3.0 are selected in this field study. The level of ground vibrations with each decoupling index was measured and the empirical particle velocity equation from these data was obtained. The condition of new cracks at blast hole are also examined. As the decoupling index is increased, the level of the blast vibration is decreased. But the cracks in rock masses are efficiently formed to remove the broken rock. The vibration constant associated with test sites is given as $K=1564.5(D.L)^{-1.3233}$ in terms of D.I.(decoupling index).

• 산업기술연구
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• 제10권
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• pp.83-88
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• 1990

The samples used for this work were low grade c1ay($Fe_2O_3$ : 2.90%, $TiO_2$ : 1.65%) produced from Youngsan-po district, and for the iron-bearing impurities removal having a bad influence on Kaoline sample was carried out column floatatoin using Oleic acid, Potassium oleat, Aero 840 promotor, Aero 870 promotor and Keroseneas collectors. For removal of the iron-vearing impurities from the kaoline, investigated first chemical composition size distribution of Kaoline sample, also performanced a basic study on pulp density, collector and pH change on a sort of frother. The flotation separation of impurities from kaoline can be achieved by using both oleic acid and Aero 840 promotor as collectors within narrow acid limits(pH 2-3). Pine oil was more effective frother than MIBC with olelic acid as aa collector.

• 산업기술연구
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• 제17권
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• pp.305-312
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• 1997

Shear connections in steel structures should satisfy dual criteria of shear strength and rotational flexibility and ductility. The connection should be strong enough to transfer the shear reaction of the beam, and should have sufficient rotational flexibility and ductility to rotate easily and supply the end rotation demand of the beam. This paper is concerned with the behavior of double-angle shear connections where the parameters are numbers of high strength bolts, bolt pitch, the length of angle leg, and connection method. An experimental investigation of shear connection was conducted by testing 12 beam-to-column joint specimens. Based on experimental and analytical study, the failure modes are developed and proposed design formulas.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4930-4935
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• 2015

180MPa급 초고성능 콘크리트는 높은 압축강도로 인해 압축 부재에 대한 연구 결과가 부족한 실정이다. 본 연구에서는 UHPC의 적용성 향상을 위해 트윈 샤프트 믹서 배치 플랜트에서 생산성을 평가하였다. 또한 설계 방안을 제시하기 위한 기초 자료를 획득하기 위해 사각 기둥과 원형 기둥에 대한 중심축하중 실험을 수행하여 파괴 형태와 거동을 평가하였다.

• 한국환경과학회지
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• 제15권3호
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• pp.229-236
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• 2006

Organophosphorus pesticides (OPPs) contents in the sewage sludge derived from the residential and industrial areas were determined in order to characterize contemporary organic contamination levels as a part of the ongoing development of the environmentally sound sewage sludge management strategy in Korea. OPPs were extracted from freeze-dried sludges in a ultrasonic extractor. The extracts were cleaned-up by florisil column and subsequently fed into gas chromatograph/nitrogen phosphorus detector (GC/NPD) for determining OPP contents. Diazinon, dimethoate, disulfoton, EPN, malathion, methyl parathion, parathion, phorate and sulfotep were present in the appreciable amount in the domestic sewage sludges. The sum of the 9 OPPs in the sewage sludge varied from 534.8 to 15552.1 ${\mu}g/kg$, dry wt..

• 한국산학기술학회논문지
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• 제12권5호
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• pp.2445-2450
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• 2011

화학공정 모사 소프트웨어인 HYSYS를 사용하여 Reformate 분리 공정을 열복합 증류탑으로 설계하였다. 열복합 증류탑 설계 방법을 자세히 하였고, 모사 결과를 일반 증류탑과 비교한 결과 제시된 열복합 증류탑 설계 방법이 간단하고 효율적이라는 것을 알 수 있었다. 같은 tray 단수하에서 열복합 증류탑은 일반 증류탑 대비 약 12.2% 에너지가 절약됨을 알 수 있었다.