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폴리카보네이트 용융중합 초기의 촉매기반 에스터 교환반응 동력학
정주연(Ju Yeon Jung),이지목(Ji Mok Lee),홍성권(Sung Kwon Hong),이진국(Jin Kuk Lee),정현민(Hyun Min Jung),김용석(Yong Seok Kim) 한국고분자학회 2015 폴리머 Vol.39 No.2
본 연구에서는 디올 단량체로서 바이오 유래 isosorbide 및 bisphenol A가 적용된 폴리카보네이트의 단일 및 공중합체를 얻기 위한 촉매로서 LiOH, Cu(acac)2 및 n-butyltin hydroxide oxide hydrate를 각각 적용하여 용융중합 초기 단계에서 에스터 교환반응의 동력학 분석을 실시하여 촉매활성도를 비교하였다. 단일 중합의 경우, Cu(acac)2가 가장 큰 촉매활성도를 나타내었으나, 서로 다른 두 가지 디올 단량체가 적용된 용융 공중합의 경우에는 촉매의 적용 메커니즘 및 단량체의 화학구조에 의존하여 LiOH의 촉매활성이 가장 큼을 확인하였다. 이러한 연구결과는 최근 관심이 집중된 바이오 유래 친환경 폴리카보네이트용 촉매선정에 활용 가능함을 제시한다. In this work, we evaluated catalytic activity of LiOH, Cu(acac)2 and n-butyltin hydroxide oxide hydrate in the early stage of the melt transesterification of isosorbide and bisphenol A as diol monomers and diphenylcarbonate for the melt polymerizaiton of polycarbonate. Cu(acac)2 proved to be the most active catalyst for homopolymerization process, while the catalytic activity of LiOH was higher than the others in case of melt copolymerization depending on the catalytic mechanism and chemical structure of catalyst. We suggested that evaluation of catalytic activity can be used for selection of catalyst system in bio-based copolymerization of polycarbonate.
한.미 FTA 정부조달 협정에 대한 국내 건설업체의 인식에 관한 연구
성주호,이진국,강중철,Sung, Joo-Ho,Lee, Jin-Kuk,Kang, Jung-Chul 한국데이터정보과학회 2009 한국데이터정보과학회지 Vol.20 No.6
본 연구는 2007년 체결된 한 미 자유무역협정 체결내용 중 정부조달협정이 건설회사에 미치는 일반적인 영향에 대한 조사와 함께, 그 영향력의 정도가 건설회사의 조직문화, 경영체제, 경영자의 리더십스타일, 경영전략 변수에 따라 달라지는지를 살펴보고자 하였다. 이러한 연구목적을 수행하고자 문헌연구와 설문조사를 통한 실증분석연구를 함께 병행하였다. 그 결과, 회사의 조직문화와 경영체제에 따라 한 미 자유무역협정에 대한 인식의 차이를 보였다. 특히 혁신 지향적 조직일수록 그리고 소유경영이 강할수록 한 미 자유무역협정에 적극적으로 대비하고 있는 것으로 나타났다. The purpose of this study is to diagnose the level of perception of domestic construction companies about the US & Korea FTA completed in 2007. According to the survey results, the more innovative the construction company is and the stronger ownership the construction company has, the more actively preparing for FTA. Altogether, our construction companies have well recognised the inevitable impacts on the domestic construction industry. On the other hand, most of them are more or less negative about whether or not the FTA gives us a good chance to switch from domestic companies into global companies.
조용숙,이진국,jung hur 대한결핵및호흡기학회 2022 Tuberculosis and Respiratory Diseases Vol.85 No.3
Background: We evaluated the effect of particulate matter (PM) and cigarette smoke extract (CSE) on bronchial epithelial cell survival, as well as oxidative stress and autophagy levels. Moreover, we aimed to assess the effect of the antioxidant N-acetylcysteine (NAC) on the adverse effects of PM and CSE exposure.Methods: Normal human bronchial epithelial cells (BEAS-2B cells) were exposed to urban PM with or without CSE, after which cytotoxic effects, including oxidative stress and autophagy levels, were measured. After identifying the toxic effects of urban PM and CSE exposure, the effects of NAC treatment on cell damage were evaluated.Results: Urban PM significantly decreased cell viability in a concentration-dependent manner, which was further aggravated by simultaneous treatment with CSE. Notably, pretreatment with NAC at 10 mM for 1 hour reversed the cytotoxic effects of PM and CSE co-exposure. Treatment with 1, 5, and 10 mM NAC was shown to decrease reactive oxygen species levels induced by exposure to both PM and CSE. Additionally, the autophagy response assessed via LC3B expression was increased by PM and CSE exposure, and this also attenuated by NAC treatment.Conclusion: The toxic effects of PM and CSE co-exposure on human bronchial epithelial cells, including decreased cell viability and increased oxidative stress and autophagy levels, could be partly prevented by NAC treatment.
CO2 와 Epoxide 의 반응에 의해 합성된 Cyclic Carbonate 의 응용 Ⅰ . Hydroxy - terminated Linear Polycarbonate 의 합성
정성미,문정열,박대원,이진국 ( S . M . Jung,J . Y . Moon,D . W . Park,J . K . Lee ) 한국공업화학회 1997 응용화학 Vol.1 No.1
In this paper, the synthesis of hydroxy-terminated linear polycarbonate was studied to understand the effect of mole ratio of initiators, kind of catalyst and structure of initiator. Mixed catalyst of potassium tert-butoxide and 18-crown-6 showed higher yield than potassium tent-butoxide alone. We also investigated the characteristics of hydroxy-terminated linear polycarbonate by DSC, TGA, GPC.
김병근 ( Byung-keun Kim ),이진국 ( Chin Kook Rhee ),정지예 ( Ji Ye Jung ),강혜련 ( Hye-ryun Kang ),조상헌 ( Sang-heon Cho ) 대한천식알레르기학회 2016 Allergy Asthma & Respiratory Disease Vol.4 No.5
Asthma and chronic obstructive pulmonary disease (COPD) are characterized by chronic airway inflammation resulting in airflow limitation. They include various phenotypes and endotypes in their disease entities. For that reason, they lack proper biomarkers and epoch-making progresses in treatment nowadays. Healthy airway has been believed to be sterile traditionally. However, with the help of nonculture sequencing techniques, researchers discovered that it is full of the commensal and symbiotic microbial flora. Therefore, microbiome has emerged as a possible biomarker and a clue to understand the pathogenesis of airway disease. Microbiome research in asthma has focused on the association between characteristics of microbiome, such as composition and diversity. However, now it refers to the role of microbiome, including Proteobacteria, in the development and pathogenesis of asthma and allergic diseases. Microbiome research in COPD has revealed its different composition according to the existence and severity of the disease. Also, differences in microbiome composition according to exacerbation state or specific treatment of COPD are reported. Therefore, many researchers pay attention to the possible role of microbiome as a biomarker or a treatment target in asthma and COPD. Herein, we review recent studies on microbiome research in asthma and COPD. (Allergy Asthma Respir Dis 2016:4:321-327)
4급 암모늄염 촉매에 의한 Glycidyl Methacrylate 와 이산화탄소의 부가반응
양정규,문정열,정성미,박대원,이진국 ( J . G . Yang,J . Y . Moon,S . M . Jung,D . W . Park,J . K . Lee ) 한국공업화학회 1996 공업화학 Vol.7 No.6
본 연구는 이산화탄소와 glycidyl methacrylate(GMA)의 부가반응에 의한(2-oxo-1,3-dioxolane-4-yl) methacrylate(DOMA)의 합성에 4급 암모늄염 촉매의 특성을 고찰한 것이다. 4급 암모늄염 상이동 촉매의 알킬기의 크기가 크고 짝음이온의 친핵성이 강할수록 촉매활성이 높았다. 폴리에틸렌글리콜이나 NaI, 18-crown-6를 단독으로 사용한 경우에는 반응활성이 전혀 없었으나 NaI와 18-crown-6의 혼합물을 촉매로 사용한 결과 비교적 좋은 DOMA 수율을 얻었다. 또한 극성이 낮은 용매를 사용한 경우에는 단량체 형태의 DOMA를 얻을 수 있었고, 극성이 높은 비양성자성 용매를 사용한 결과 DOMA의 고분자를 직접 합성할 수 있었다. 한편 고압 회분반응기에서 이산화탄소의 압력변화를 통한 속도론적 고찰 결과 반응속도는 GMA와 이산화탄소의 농도에 대하여 각각 1차 반응이었고, 이때 반응속도 상수 k는 0.56L/mol·hr이었으며 diglyme 용매에 대한 80℃에서 CO₂의 Henry 상수 H`는 6.5×10^(-4)mol/L·kPa로 나타났다. This study is related to the investigation of the characteristics of quaternary ammonium salt catalyst on the addition reaction of carbon dioxide and glycidyl methacrylate(GMA) to form(2-oxo-l,3-dioxolane-4-yl) methacrylate(DOMA). Among the salts tested, the ones with higher alkyl chain length and with more nucleophilic counter anion showed a higher catalytic activity. Mixed catalysts of NaI and 18-crown-6 showed a good yield of DOMA, but when they are used alone, they showed no catalytic activity. The DOMA monomer was obtained in low polar solvents, while poly(DOMA) could be directly synthesized in aprotic dipolar solvents. Kinetic studies carried out by measuring CO₂ pressure in a high pressure batch reactor showed that the reaction rate was first order to the concentration of GMA and CO₂ respectively. The rate constant(k) was 0.56L/mol·hr and Henry`s constant(H`) of CO₂in diglyme at 80℃ was 6.5×10^(-4)mol/L·kPa.