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자동차 배기계용 POS AL409L 스테인리스강의 개발과 부품성능평가
김영호(Yeongho Kim),조성준(Seongjun Cho),박찬하(Chanha Park),박종환(Jonghwan Park),장민(Min Jang),박종휘(Jonghwi Park) 한국자동차공학회 2011 한국자동차공학회 부문종합 학술대회 Vol.2011 No.5
Al-coated stainless steel has been developed for the materials of automotive exhaust systems. This new materials, POS AL409L, showed excellent corrosion resistance in the condensed water environment of muffler and also in the deicing salt environments because aluminum can prevent the corrosion of stainless steel by acting as a sacrificial anode. Mechanical strength and ductility are also satisfied with the specification as exhaust materials. The corrosion resistance of automotive exhaust system with POS AL409L was superior to those of STS439 and STS409L. It showed that aluminum coating was not deteriorated in manufacturing process and the lifetime of vehicle exhaust system can be prolonged.
EPDM/Bottom Ash 복합재료의 형태학 및 물리적 특성
김영호(Yeongho Kim),심현석(Hyunseok Shim),이민호(Minho Lee),민병훈(Byong Hun Min),김정호(Jeong Ho Kim) 한국청정기술학회 2013 청정기술 Vol.19 No.3
EPDM 고무는 여러 가지 용도에 많이 사용되고 있는 소재이다. 화력발전소의 소각로에서 부산물로 발생하는 버텀애쉬(bottom ash)는 플라이애쉬(fly ash)와는 달리 재활용이 거의 되지 않고 있는데, 본 연구에서는 버텀애쉬 및 탈크를 포함하는 EPDM 복합소재를 roll-mill을 이용하여 제조한 후, 기계적, 열적, 전기적 및 경화 특성 등을 분석하였다. 또한 주사전자현미경(scanning electron microscopy, SEM)을 이용하여 복합재료의 모폴로지를 관찰하였다. 일부의 버텀애쉬는 계면활성제를 이용하여 개질한 후 EPDM 복합재료를 제조하여 개질의 효과를 조사하였다. 결과로 개질된 버텀애쉬 및 탈크를 포함하는 EPDM 복합재료는 우수한 인장 강도 및 인장 탄성률을 나타내었다. EPDM 복합재료의 체적 저항은 10<SUP>14</SUP> Ωcm 이상으로 전기 절연체로서 저항 임계치를 만족하였고, 열적 물성 결과 버텀애쉬 및 탈크가 EPDM의 열적 안정성을 높여 주는 것으로 확인되었다. Ethylene propylene diene terpolymer (EPDM) has been usually used for various applications. Bottom ash generated in thermoelectric power plant is hardly recycled. In this study, EPDM/bottom ash/talc composites were prepared by using roll-mill. Bottom ashes obtained from thermoelectric power plant were modified using surfactant. The processing materials used in this study were antioxidant, processing oil, cross-linking co-agent and softening agent. Morphology and physical properties of EPDM composites are investigated by using SEM, TGA, UTM and Rheometer. As a result, when modified ash and talc are added to EPDM composites, the tensile strength and modulus of EPDM composites were remarkably enhanced.
비수계 분산중합으로 제조된 환경친화성 아크릴수지/나노클레이 복합재료의 특성 연구
김영호 ( Yeongho Kim ),이민호 ( Minho Lee ),전현열 ( Hyeonyeol Jeon ),이영철 ( Young Chul Lee ),민병훈 ( Byong Hun Min ),김정호 ( Jeong Ho Kim ) 한국화학공학회 2016 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.54 No.1
본 연구에서는 아크릴과 소량의 스티렌 모노머에 나노클레이인 순수한 몬모릴로나이트(Pristine monmorillonite: PM) 또는 개질된 몬모릴로나이트(30B 또는 25A)를 첨가한 후 비수계 분산(NAD) 중합에 의해 환경친화성 아크릴/나노클레이 NAD수지 복합재료를 제조하고 나노클레이가 이 NAD 수지의 중합물성 및 복합재료의 물리적 물성에 주는 영향에 대해 연구하였다. 중합 후의 NAD 수지의 입자 균일성 측면에서 나노클레이는 초기에 안정제와 함께 투입하는 것이 유리하였고 중합된 NAD수지의 고형분, 산가, 점도 결과에서는 유기화제로 개질된 25A를 첨가할 경우가 다른 나노클레이를 첨가할 경우보다 좋은 물성을 주는 것으로 나타났다. 25A첨가 NAD수지는GPC 측정시 분자량의 증가와 다분산지수의 감소로도 좋은 물성이 확인되었다. 나노클레이25A가 수지내에 잘 분산된 것은XRD결과에서 나노클레이의 층간거리 증가로 확인 되었고 열적 물성 측정 결과와 동적 기계적 물성 측정에서도 나노클레이25A를 포함한 NAD수지의 유리전이온도가 가장 높게 나타났으며 저장 탄성율 또한 25A경우가 가장 우수한 것으로 관찰되었다. 따라서 비수계 분산중합에 의해 아크릴/나노클레이 NAD수지를 제조할 경우에는 나노클레이로 25A를 첨가하는 것이 가장 좋은 물성을 얻을 수 있음을 확인할 수 있었다. Eco-friendly acrylic resin/clay nanocomposites containing pristine montmorillonite (PM) or modified clays (30B and 25A) were prepared from acrylic and styrenic monomers using non-aqueous dispersion (NAD) polymerization. Effect of nanoclays on physical properties of polymerization product and resulting nanocomposites was investigated. In view of NAD particle stability, addition of nanoclay at the beginning of polymerization is proved to be good. Results of gel fraction, acid value and viscosity of the NAD product showed that nanocomposites containing clay 25A showed better physical properties than the ones with other clays. GPC results exhibit the increase in molecular weight and decrease in polydispersity index for the 25A nanocomposite. Increase in layer distance confirmed from XRD analysis showed good dispersion of 25A in the nanocomposite. Thermal and dynamic mechanical analysis showed that highest glass transition temperature and storage modulus for 25A nanocomposites. These results indicate that 25A nanoclay gives the best properties in the process of non-aqueous dispersion polymerization of acrylic resin/nanoclay nanocomposites.
한국 초,중,고등학생 알레르기비염의 전국 유병률과 위험 인자에 대한 분석
김영호 ( Yeongho Kim ),서주희 ( Ju Hee Seo ),권지원 ( Ji Won Kwon ),이은 ( Eun Lee ),양송이 ( Song I Yang ),조현주 ( Hyun Ju Cho ),하미나 ( Mina Ha ),범은애 ( Eunae Burm ),이기재 ( Kee Jae Lee ),김환철 ( Hwan Cheol Kim ),임신예 ( Si 대한천식알레르기학회 2015 Allergy Asthma & Respiratory Disease Vol.3 No.4
Purpose: We investigated the prevalence and risk factors of allergic rhinitis (AR), nationwide in random children and adolescents of Korea. Methods: A modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire survey was done in 1,820 children from elementary, middle, and high school nationwide in Korea. The subjects were selected by the stratifying sampling method by school grade and five regions. Current AR was defined as having AR symptoms during the last 12 months with a history of physician-diagnosed AR. Skin prick tests for 18 common allergens were performed. Results: The number of males was 945, and that of females was 875. The mean age of the patients was 12.61±3.40 years. The prevalence of current AR and atopic current AR were 29.0% and 18.7%, respectively. Risk factors for current AR were male (adjusted odds ratio [aOR], 1.486; 95% confidence interval [CI], 1.189.1.856), family history of paternal AR (aOR, 3.208; 95% CI, 2.460.4.182), family history of maternal AR (aOR, 3.138; 95% CI, 2.446.4.025), antibiotic use in infancy (aOR, 1.547; 95% CI, 1.228.1.949), mold exposure during infancy (aOR, 1.416; 95% CI, 1.103.1.819), mold exposure during the last 12 months (aOR, 1.285; 95% CI, 1.012.1.630), and sensitization on skin prick tests (aOR, 2.596; 95% CI, 2.055.3.279). Risk factors for atopic current AR were the same as those of current AR, whereas breast-milk feeding (aOR, 0.720; 95% CI, 0.530.0.976) was a protective factor. Sensitized allergens as risk factors for current AR were Dermatophagoides pteronyssinus, Dermatophagoides farina, ragweed, mugwort, oak, alder, birch, Japanese hop, cat, and dog. Conclusion: The prevalences of current AR and atopic current AR were 29.0% and 18.7%, respectively. Male, sex parental AR, antibiotic use in infancy, mold exposure during the last 12 months, mold exposure during infancy, and atopic sensitization were risk factors for current AR. Breast-milk feeding was a protective factor for atopic current AR. Aeroallergen sensitization was an important risk factor for AR. (Allergy Asthma Respir Dis 2015;3:272-280)