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        검색결과 586

        181.
        2017.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigated a Leidenfrost effect in the growth of ZnO nanostructures on silicon substrates by ultrasonic-assisted spray pyrolysis deposition(SPD). Structural and optical properties of the ZnO nanostructures grown by varying the growth parameters, such as substrate temperature, source concentration, and suction rate of the mist in the chambers, were investigated using field-emission scanning electron microscopy, X-ray diffraction, and photoluminescence spectrum analysis. Structural investigations of the ZnO nanostructures showed abnormal evolution of the morphologies with variation of the substrate temperatures. The shape of the ZnO nanostructures transformed from nanoplate, nanorod, nanopencil, and nanoprism shapes with increasing of the substrate temperature from 250 to 450 °C; these shapes were significantly different from those seen for the conventional growth mechanisms in SPD. The observed growth behavior showed that a Leidenfrost effect dominantly affected the growth mechanism of the ZnO nanostructures.
        4,000원
        189.
        2017.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The microstructural evolution and modulation of mechanical properties were investigated for a Ti65Fe35 hypereutectic alloy by addition of Bi53In47 eutectic alloys. The microstructure of these alloys changed with the additional Bi- In elements from a typical dendrite-eutectic composite to a bimodal eutectic structure with primary dendrite phases. In particular, the primary dendrite phase changed from a TiFe intermetallic compound into a β-Ti solid solution despite their higher Fe content. Compressive tests at room temperature demonstrated that the yield strength slightly decreased but the plasticity evidently increased with an increasing Bi-In content, which led to the formation of a bimodal eutectic structure (β-Ti/TiFe + β- Ti/BiIn containing phase). Furthermore, the (Ti65Fe35)95(Bi53In47)5 alloy exhibited optimized mechanical properties with high strength (1319MPa) and reasonable plasticity (14.2%). The results of this study indicate that the transition of the eutectic structure, the type of primary phases and the supersaturation in the β-Ti phase are crucial factors for controlling the mechanical properties of the ultrafine dendrite-eutectic composites.
        4,000원
        190.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A dimensionally stable anode based on the RuO2 electrocatalyst is an important electrode for generating chlorine. The RuO2 is well-known as an electrode material with high electrocatalytic performance and stability. In this study, sonoelectrodeposition is proposed to synthesize the RuO2 electrodes. The electrode obtained by this novel process shows better electrocatalytic properties and stability for generating chlorine compared to the conventional one. The high roughness and outer surface area of the RuO2 electrode from a new fabrication process leads to increase in the chlorine generation rate. This enhanced performance is attributed to the accelerated mass transport rate of the chloride ions from electrolyte to electrode surface. In addition, the electrode with sonodeposition method showed higher stability than the conventional one, which might be explained by the mass coverage enhancement. The effect of sonodeposition time was also investigated, and the electrode with longer deposition time showed higher electrocatalytic performance and stability.
        4,200원
        191.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        RuO2 is a common active component of Dimensionally Stable Anodes (DSAs) for chlorine evolution that can be used in wastewater treatment systems. The recent improvement of chlorine evolution using nanostructures of RuO2 electrodes to increase the treatment efficiency and reduce the energy consumption of this process has received much attention. In this study, RuO2 nanorod and nanosheet electrodes were simply fabricated using the sol-gel method with organic surfactants as the templates. The obtained RuO2 nanorod and nanosheet electrodes exhibit enhanced electrocatalytic activities for chlorine evolution possibly due to the active surface areas, especially the outer active surface areas, which are attributed to the increase in mass transfers compared with a conventional nanograin electrode. The electrocatalytic activities for chlorine evolution were increased up to 20 % in the case of the nanorod electrode and 35% in the case of the nanosheet electrode compared with the nanograin electrode. The RuO2 nanorod 80 nm in length and 20-30 nm in width and the RuO2 nanosheet 40-60 nm in length and 40 nm in width are formed on the surface of Ti substrates. These results support that the templated RuO2 nanorod and nanosheet electrodes are promising anode materials for chlorine evolution in future applications.
        4,000원
        192.
        2017.10 구독 인증기관·개인회원 무료
        Trophic associations of lepidopteran larvae have been formed from a long period of evolution. The larva of Oecophoridaecan keep being concealed with several strategies. They may be sheltered within a web or hidden under bark or deadwood, or inside leaves rolled by them. Sometimes they bore stem or trunk or burrow under bark or hide in soil. In addition,they can also be found in very diverse and specialized microhabitats. This study was to assess the ancestral characterstate of microhabitat and larva sheltering strategy within the phylogenetic relationship of Oecophoridae to understand theirevolutionary transition and the adaptation of larva to microhabitats using sheltering strategies. Also, it is to investigatethe historical biogeography and evolution of the family Oecophoridae and related higher taxa for understanding their globalradiation and distribution.
        193.
        2017.10 구독 인증기관·개인회원 무료
        New Zealand split from the rest of Gondwana 65-80 my and is home to approximately 6000 species of beetles, manyof which are undescribed and or poorly studied. Like other iconic groups of New Zealand organisms, the beetle faunais composed of ancient relict lineages and endemic radiations, indicative of an island continental island which never hadopen ecological niches as seen in deep islands such as Hawaii or the Galapagos archipelagos. While more recent volcanismand glaciation as well as the arrival of man within the past 1000 yrs has shaped the population structure and distributionof New Zealand beetles, a new comprehensive model for the evolution of beetles is proposed.
        194.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Science and Religion is a Christian apology that was written in response to the intellectual discourse of the 1920s, when materialistic socialism was rapidly propagated to intellectual youth as scientific discourse. Van Buskirk, a professor at the Severance Medical Research Department, combines the ideology of science, which was a qualification for knowledge, with Christian doctrine. In this way, Buskirk's text constitutes a Christian social evolution theory. Specifically, the narrative frame of Darwinism, which had already been approved by science, is dedicated to selectively combine the doctrine of salvation, soul, love, and sacrifice. With this, it criticized the materialism and the mechanical determinism of materialistic socialism which has emerged as a dominant discourse, and built a discourse that would cope with it. It thus provides an important key to identifying the role of Christianity in the formation of knowledge discourse in the 1920’s.
        5,500원
        196.
        2017.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        복합제품시스템이란 고도의 엔지니어링과 설계 기술이 집약되어 있는 복잡한 시스템 형태의 제품으로 국가 경제 발전 및 에너지, 교통, 통신 등 사회 인프라 구축과 밀접 하게 연계되어 있다. 이에 따라 복합제품시스템의 기술진화를 이해하기 위해서는 기술개발 주체의 기술진보 노력을 넘어서 복합제품시스템을 둘러싼 거시환경요인이 기술진화에 미친 영향을 복합적으로 고찰하는 것이 필요하다. 이에 따라 본 연구에서는 원자력 발전 플랜트 사례를 중심으로 복합제품시스템 기술진화에 대한 정책, 경제, 그리고 사회적 요인의 영향을 종단적으로 서술하였다. 인터뷰에 기반한 1차 자료와 다양한 참고 문헌에 기반한 2차 자료를 복합적으로 활용한 결과, 원전 기술의 진화는 “원자력의 평화적 활용을 위한 응용연구”(1950년대~1960년대), “원자력 발전 시장 확산-1차 르네상스”(1970년대), “원자력 발전 안전성 제고와 후발국의 추격”(1980년대~2000년대 후반), 그리고 “원자력 발전 시장 2차 르네상스 를 위한 안전성의 최우선화와 차세대 원자로 기술 개발”(2010년대 후반~현재)의 4단계에 걸쳐 진행되는 것으로 나타났다. 또한 각 단계별 기술진화에 있어 각국의 에너지 정책과 원자력 발전 연구개발 투자와 같은 정책적 요인, 경기 사이클에 의한 전력 수요의 변화, 전력원 간 경쟁과 같은 경제적 요인, 그리고 안전성에 대한 사회적 수용과 환경오염에 대한 인식 등 의 사회적 요인 등이 중요한 영향을 미쳤음을 확인하였다. 본 사례 연구는 보다 거시적인 관점에서 복합제품시스템의 기술진화를 고찰할 수 있는 이론적 접근방법을 제시하였다는 점에서 그 의의가 있다. 따라서 복합제품시스템을 육성하고자 하는 국가들은 기술개발 투자와 노력뿐 아니라 정책과 경제, 사회적 요인을 통합적으로 고려하여 이를 기술진화에 활용하기 위한 노력을 경주해야 할 것이다.
        8,400원