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        검색결과 25

        21.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon supported electrocatalysts are commonly used as electrode materials for polymer electrolyte membrane fuel cells(PEMFCs). These kinds of electrocatalysts provide large surface area and sufficient electrical conductivity. The support of typical PEM fuel cell catalysts has been a traditional conductive type of carbon black. However, even though the carbon particles conduct electrons, there is still significant portion of Pt that is isolated from the external circuit and the PEM, resulting in a low Pt utilization. Herein, new types of carbon materials to effectively utilize the Pt catalyst are being evaluated. Carbon nanofiber/activated carbon fiber (CNF/ACF) composite with multifunctional surfaces were prepared through catalytic growth of CNFs on ACFs. Nickel nitrate was used as a precursor of the catalyst to synthesize carbon nanofibers(CNFs). CNFs were synthesized by pyrolysising CH4 using catalysts dispersed in acetone and ACF(activated carbon fiber). The as-prepared samples were characterized with transmission electron microscopy(TEM), scanning electron microscopy(SEM). In TEM image, carbon nanofibers were synthesized on the ACF to form a three-dimensional network. Pt/CNF/ACF was employed as a catalyst for PEMFC. As the ratio of prepared catalyst to commercial catalyst was changed from 0 to 50%, the performance of the mixture of 30 wt% of Pt/CNF/ACF and 70wt% of Pt/C commercial catalyst showed better perfromance than that of 100% commercial catalyst. The unique structure of CNF can supply the significant site for the stabilization of Pt particles. CNF/ACF is expected to be promising support to improve the performance in PEMFC.
        3,000원
        22.
        2009.11 구독 인증기관 무료, 개인회원 유료
        현대의 산업은 점차 분야가 다양해지고 기술이 첨단화되며, 고객의 요구사항이 복잡해지고 있다. 이에 따라 제조업에서는 초정밀, 고신뢰도가 요구되어지고 있는 실정이다. 제조업 분야의 핵심 기술인 SPC기법 중에서 누적합(CUSUM) 관리도는 공정의 작은 변화에 대해서 민감하다는 특징 때문에 첨단 산업인 반도체나 화학공정 등에서 활용도가 높은 관리도 기법이다. 하지만 복잡한 이론 체계로 인하여 사용편리성이 떨어진다는 단점이 있다. 본 논문에서는 누적합 관리도의 이론적 전개에 관한 체계적인 조사연구를 통해 누적합 관리도의 복잡한 이론 체계를 이해하는데 도움이 되고자 한다.
        4,000원
        23.
        2009.04 구독 인증기관 무료, 개인회원 유료
        전 세계적으로 이상 고온, 폭우, 가뭄, 지진, 해일 등이 빈번하게 발생하고 있다. 그 피해 규모도 앞으로 계속 커질 전망이다. 경제활동의 주체인 기업이 이러한 자연 재해로 인하여 지속적이고 안정적으로 운영되지 못하게 된다면 이는 기업자체는 물론 치 열한 글로벌 경쟁체제 속에서 국가경쟁력향상에 상당한 타격을 줄 수 있다. 하지만 우리나라의 기업은 선진국에 비해 상대적으로 자연재해 발생 시 체계적인 방재시스템을 구축하지 못하고 있다. 본 논문에서는 자연재해저감기술 개발의 필요성과 선진국가의 사례들을 통한 우리나라의 자연재해저감기술이 나아갈 방향성을 모색하고자 한다.
        4,000원
        24.
        2008.11 구독 인증기관 무료, 개인회원 유료
        Since korea must get 5.2% reduction of green gas emission and insecurity of economic impact is on the increase due to unstable oil market, the demands of energy saving techniques are increasing. In this paper, we investigate necessity of development of enormous energy used cleanroom energy saving techniques furthermore we also investigate the adoption of dependability management system to develop the energy saving cleanroom development process.
        4,000원
        25.
        2022.12 KCI 등재후보 서비스 종료(열람 제한)
        In this study, probiotic properties such as acid resistance, bile tolerance, intestinal adhesion and fat accumulation inhibition of lactic acid bacteria isolated from kimchi were investigated in order to develop probiotics effective anti-adipogenic effects. Among the 120 types of lactic acid bacteria isolated from kimchi, 42 types of lactic acid bacteria being to acid resistance, 35 types of lactic acid bacteria being to bile resistance, and 24 types of lactic acid bacteria being to both acid resistance and bile resistance were selected. These 24 types were tested for the intestinal adhesion ability which is an essential factor of probiotics’ function and L. rhamnosus GG was used as a positive control in this test. 10 types of lactic acid bacteria having the intestinal adhesion ability were selected. The selected 10 types of lactic acid bacteria were treated in 3T3-L1 cells and intracellular fat was stained with Oil Red O reagent to measure fat accumulation. As a result, in the group treated with lactic acid bacteria OS-15, 48, 102 and 120, fat accumulation was significantly decreased compared with the non-treated group. And the strain OS-48 showed the greatest inhibitory effect on fat accumulation. The lactic acid bacterium OS-48 was identified as Lactiplantibacillus plantarum by analysis based on 16S rRNA sequencing and was named Lactiplantibacillus plantarum OS-48. Therefore, based on the results of this study, L. plantarum OS-48 is expected to be very useful as probiotics with anti-obesity effect in the food industry such as fermented food and functional food.
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