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        검색결과 2,514

        428.
        2019.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        There are several manufacturing techniques for developing thermionic cathodes for vacuum ultraviolet(VUV) ionizers. The triple alkaline earth metal emitters(Ca-Sr-Ba) are formulated as efficient and reliable thermo-electron sources with a great many different compositions for the ionizing devices. We prepare two basic suspensions with different compositions: calcium, strontium and barium. After evaluating the electron-emitting performance for europium, gadolinium, and yttrium-based cathodes mixed with these suspensions, we selected the yttrium for its better performance. Next, another transition metal indium and a lanthanide metal neodymium salt is introduced to two base emitters. These final composite metal emitters are coated on the tungsten filament and then activated to the oxide cathodes by an intentionally programmed calcination process under an ultra-high vacuum(~10-6 torr). The performance of electron emission of the cathodes is characterized by their anode currents with respect to the addition of each element, In and Nd, and their concentration of cathodes. Compared to both the base cathodes, the electron emission performance of the cathodes containing indium and neodymium decreases. The anode current of the Nd cathode is more markedly degraded than that with In.
        4,200원
        429.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to establish a strategy for selling kimchi to satisfy the needs and wants of European consumers through survey, FGI, and IDI. All survey participants were Europeans and were selected on the basis of their kimchi awareness. For the quantitative survey, 246 participants 15 years or older were selected; for FGI, 33 participants aged between 20 and 49 were selected; and for IDI, eight chefs were selected. The survey included four steps of ‘Awareness-First try-Needs-Future consumption’. The participants got to know kimchi through the Internet; for example, by visiting Korea and Hallyu, and suggested positive comments, including ‘fancy’ and ‘exotic.’ While satisfaction with kimchi sharply decreased due to taste and appearance in the first try of kimchi, it is important to provide the best first-try experience. It also showed that important needs for kimchi are ‘hot sensation’ , ‘crunchiness’ and ‘presentation’. They gave a negative answer to combination with traditional cuisines of their own country, but provided positive comments for benchmarking the use of traditional pickled foods. This study suggests that it may be necessary to implement a two-track strategy by the traditional kimchi as a ‘strategic product’ and localized kimchi as a ‘key product’.
        5,100원
        430.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        백두산에서는 밀레니엄 대분화 이후로도 수차례의 화산활동이 계속되어 마그마 거동 감시 연구의 필요성이 지속적으로 제기되고 있다. 마그마방의 깊이 및 규모를 파악하기 위해서는 다양한 지구물리학적 접근이 필요하며, 본 연구에서는 전기비저항 탐사의 적용성을 검토하고자 한다. 국경으로 인해 공간적 제한이 있는 백두산에서 심부에 위치한 마그마를 탐사하기 위해서는 측선의 길이가 수십 킬로미터 이상이 되는 대규모 전기탐사가 이루어져야 하며, 이를 위해 서는 분산계측 시스템의 도입과 이에 최적화된 탐사 설계가 필수적으로 요구된다. 따라서 자체 개발된 분산계측 시스템을 활용하는 탐사설계안을 제시하고 전산실험을 통해 적용 가능성을 분석하였다. 단일 측선과 비동일선상 송신원 배열을 사용한 탐사설계안을 이용하여 다수의 측선 설치가 필요한 일반적인 3차원 탐사에 준하는 역산 해석 결과를 얻을 수 있음을 확인하였으며, 이 탐사설계안이 백두산 심부 물리탐사에 유용하게 적용될 수 있을 것으로 기대된다.
        4,200원
        431.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 실험은 물냉이 수경재배 시 양액 내 발생 시킨 마이크로버블이 물냉이의 생육과 glucosinolate 축적에 미치는 영향을 알아보기 위해 수행되었다. 본엽 4매의 물냉이 유묘(파종 2주 후)를 마이크로 버블과 비-마이크로버블을 발생시킨 오오츠카 배양액을 이용하여 환경조절룸에서 3주간 재배하였다. 물냉이 초장은 대조구처리가 마이크로버 블처리보다 41% 증가하였으며, 유의적으로 높게 나타났다. 그러나, 지상부 생체중과 건물중, 근장, 엽장, 엽폭, SPAD, 량자수율값은 두처리간 유의적 차이는 나타나지 않았다. Glucosinolate 함량을 분석 결과 4-methoxygluco-brassicin을 제외한 glucoiberin, glucobrassicin, gluconapin, gluconasturtiin의 경우 마이크로버블 처리구가 대조구보다 유의적으로 높게 나타났으며, 물냉이 한주 당 총 glucosinolate 함량은 마이크로버블 처리구가 대조구 보다 85%(μmol/g DW)와 65%(μmol/plant) 더 높게 나타났다. 본 연구 결과는 담액재배시 양액 내 마이크로버블 이 물냉이의 glucosinolate 함량을 증가시킬 수 있을 것으로 나타났다.
        4,000원
        432.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Total organic carbon(TOC) was introduced as the water quality index of the rivers and lakes in 2013. This paper evaluated factors affecting effluent TOC concentrations and treated and discharged loads of existing publicly owned treatment works(POTWs). For selected POTWs with greater treatment capacity than 500㎥/day, factorial analysis was used to consider effects of kinds of biological treatment processes, inflow of other types of wastewater(industrial, livestock, landfill leachate wastewater, etc.) with domestic wastewater, sewer separation rate, and effluent discharging zones in which different effluent criteria applied. As a result, those factors did not show significant effect on effluent TOC concentration of POTWs in effluent discharging zone Ⅰ and Ⅱ. However, In effluent discharging zone Ⅲ and Ⅳ, kinds of biological treatment processes, the inclusion of other waste in influent of domestic wastewater, and the sewer separation rate were significant factors. The treated TOC load in POTWs was also not affected significantly by the variables set in this study. On the other hand, those three factors influenced significantly on the TOC load discharged to water bodies. The sum of factorial effects and the contribution rate of three factors to the discharged TOC load was 60.23 and 41%, 59.57 and 41%, and 42.04 and 18%, respectively.
        4,000원
        433.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tungsten carbide (WC) hard materials are used in various industries and possess a superior hardness compared to other hard materials. They have particularly high melting points, high strength, and abrasion resistance. Accordingly, tungsten carbide hard materials are used for wear-resistant tools, cutting tools, machining tools, and other tooling materials. In this study, the WC-5wt.%Co, Fe, Ni hard materials are densified using the horizontal ball milled WC-Co, WC-Fe, and WC-Ni powders by a spark plasma sintering process. The WC-5Co, WC-5Fe, and WC-5Ni hard materials are almost completely densified with a relative density of up to 99.6% after simultaneous application of a pressure of 60 MPa and an electric current for about 15 min without any significant change in the grain size. The average grain size of WC-5Co, WC-5Fe, and WC-5Ni that was produced through SPS was about 0.421, 0.779, and 0.429 μm, respectively. The hardness and fracture toughness of the dense WC-5Co, WC-5Fe, WC-5Ni hard materials were also investigated.
        4,000원