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        검색결과 19

        3.
        2016.11 구독 인증기관·개인회원 무료
        The hollow fiber membranes were prepared via hybrid process of the thermally induced phase separation(TIPS) and the non-solvent induced phase separation(NIPS). The spinning dope solution consisted of poly(vinylidene fluoride) (PVDF) / dibutyl phthalate (DBP) / 1-methyl-2-pyrrolidone (NMP), where DBP was used as a diluent and NMP as a solvent for PVDF. Various bore fluids were tested different ratio solvent/diluent mixture. Depending on the miscibility of dope solution and internal coagulant the samples underwent the different phase separation mechanisms and rates. Phase separation mechanism study for various combinations were performed to support the interpretation of the membrane structure. Membrane characterizations were performed such as water flux, porosity, pore size, and mechanical strength.
        4.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sense of place (SOP) has recently been considered an effective strategy through which to pursue sustainable place development. However, many urban spaces have not usually considered the contribution of built-environment factors to SOP and SOP’s contribution to people’s willingness to revisit for sustainable place. Therefore, this research aims to understand the internal structure of SOP at Daehak-ro, one of the most famous cultural district and tourism sites in Seoul, Korea. Through this study, the sociocultural factor was found to make the greatest contribution to Daehak-ro’s SOP, and SOP was itself found to be highly related to willingness to revisit. These results suggest that non-physical factors could be most important to developing an SOP in urban environments. This study will eventually lead to better understanding of developing SOP, and will contribute to Daehak-ro becoming more sustainable than at present.
        4,500원
        5.
        2016.05 구독 인증기관·개인회원 무료
        The hollow fiber membranes were prepared via hybrid process of the thermally induced phase separation(TIPS) and the non-solvent induced phase separation(NIPS). The spinning dope solution consisted of poly(vinylidene fluoride) (PVDF) / dibutyl phthalate (DBP) / 1-methyl-2-pyrrolidone (NMP), where DBP was used as a diluent and NMP as a solvent for PVDF. Bore fluids were tested different ratio solvent/ethanol and diluent/ethanol mixture. The membrane structure was analyzed by SEM and FT-IR to confirm phase separation mechanisms. Various structures were obtained due to the different phase separation mechanism. Membrane characterizations were performed such as water flux, pore size, rejection efficiencies and mechanical strength.
        6.
        2015.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigate physical properties of the nearby (∼ 7.5 pc) astrometric binary μ Cas in the context of standard evolutionary theory. Based on the spectroscopically determined relative abundances ([ /Fe] & +0.4 dex, [Fe/H] ∼ −0.7 dex), all physical inputs such as opacities and equation of state are consistently generated. By combining recent spectroscopic analyses with the astrometric observations from the HIPPARCOS parallaxes and the CHARA array, the evolutionary model grids have been constructed. Through the statistical evaluation of the 2-minimization among alternative models, we find a reliable evolutionary solution (MA, MB, tage) = (0.74 M⊙, 0.19 M⊙, 11 Gyr) which excellently satisfies observational constraints. In particular, we find that the helium abundance of μ Cas is comparable with the primordial helium contents (Yp ∼ 0.245). On the basis of the well-defined stellar parameters of the primary star, the internal structure and the p-mode frequencies have been estimated. From our seismic computation, μ Cas is expected to have a first order spacing  ∼ 169 μHz. The ultimate goal of this study is to describe physical processes inside a low-mass star through a complete modelling from the spectroscopic observation to the evolutionary computation.
        4,200원
        7.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ohmic heating uses electric resistance heat which occurs equally and rapidly inside food when the electrical current is transmitted into. Prior to the study, we have researched the potato starch’s thermal property changes during ohmic heating. Comparing with conventional heating, the gelatinization temperature and the range of potato starch treated by ohmic heating are increased and narrowed respectively. This result is appeared equally at wheat, corn and sweet potato starch. At this study, we treated potato, wheat, corn and sweet potato starch by ohmic/conventional method and observed change of external structure by microscope and internal structure by X-ray diffractometer. Conventional heated at 55℃ potato starch was not external structural changes. But ohmic heated potato starch is showed largely change. Some small size starch particle were broken or small particles are made of larger particle together or small particles caught up in the large particle. Changes in ohmic heated potato starch at 60℃ was greater. The inner matter came to an external particle burst inside and only the husk has been observed. The same change was observed in the rest of the starch. The change of internal structure of potato starch was measured using X-ray diffraction patterns. There was no significant difference between ohmic and conventional heating at 55℃. But almost every peak has disappeared ohmic at 60℃. Especially 5.4° peak to represent the type B was completely gone. When viewed from the above results, external changes with change in the internal crystal structure of the starch particles were largely unknown to appear. In conclusion, during ohmic heating changes of starch due to the electric field with a change in temperature by the heating was found to have progressed at the same time.
        4,000원
        12.
        1999.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        직경이 각각 4,6,8,12 및 15mm인 순Al 또는 Al-(1,2,3wt%) Cu합금 내부냉금이 95mm ø×200mm H 크기의 흑연주형 중심부에 설치되었다. 이 내부냉금과 같은 조성의 용융금속이 750˚C의 주입온도에서 주형에 주입되었고, 냉각속도, 응고조직 및 성분편석이 분석되었다. 주괴직경/내부냉금직경의 비가 8까지 증가될수록 결정립도, 2차수지상간격 및 성분편석이 현저하게 감소됨이 확인되었다. 그러나 이 비가 8이상이 되면, 미용해 내부냉금이 발생되고, 내부냉금의 효과는 급속히 감소되었다. 순Al 및 Al-(1,2,3wt%)Cu 합금에서 최대 내부냉금 효과를 얻을 수 있는 적정 주괴직경/내부냉금직경의 비는 750˚C주입온도에서는 8이었다.
        4,000원
        13.
        2019.10 서비스 종료(열람 제한)
        원전격납구조물, LNG 저장탱크와 같은 프리스트레스트 콘크리트 (Prestressed Concrete, PSC) 사회기반시설물의 경우 테러, 폭발, 충돌 사고로 인해 대량의 경제적, 인적 피해가 발생할 수 있으나 폭발, 충돌 등의 극한하중에 따른 방호 및 방재개념의 구조설계가 적용되지 않은 실정이다. 특히, 구조물 내부에서 발생하는 폭발하중은 압력이 외부폭발하중에 비해 월등히 크기 때문에 내부폭발하중에 대한 특성 및 내부폭발하중에 따른 PSC 구조물의 저항성능의 검토는 필수적이다. 따라서, 본 연구에서는 PSC 관형 구조물의 내부폭발저항성능을 검토하기 위해 이방향 PSC 축소모형을 제작하여 실험적으로 검토하였으며 실험 데이터를 기반으로 해석적 모델을 개발 및 검증하였다.
        14.
        2017.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this study, the internal structure of a Heumgyeonggak-nu (欽敬閣漏) was designed, and the power transmission mechanism was analyzed. Heumgyeonggak-nu is an automated water clock from the Joseon Dynasty that was installed within Heumgyeonggak (欽敬閣), and it was manufactured in the 20th year of the reign of King Sejong (1438). As descriptions of Heumgyeonggak-nu in ancient literature have mostly focused on its external shape, the study of its internal mechanism has been difficult. A detailed analysis of the literature record on Heumgyeonggak-nu (e.g., The Annals of the Joseon Dynasty) indicates that Heumgyeonggaknu had a three-stage water clock, included a waterfall or tilting vessel (欹器) using the overflowed water, and displayed the time using a ball. In this study, the Cheonhyeong apparatus, water wheel, scoop, and various mechanism wheels were designed so that 16 fixed-type scoops could operate at a constant speed for the water wheel with a diameter of 100 cm. As the scoop can contain 1.25 l of water and the water wheel rotates 61 times a day, a total of 1,220 l of water is required. Also, the power gear wheel was designed as a 366-tooth gear, which supported the operation of the time signal gear wheel. To implement the movement of stars on the celestial sphere, the rotation ratio of the celestial gear wheel to the diurnal motion gear ring was set to 366:365. In addition, to operate the sun movement apparatus on the ecliptic, a gear device was installed on the South Pole axis. It is expected that the results of this study can be used for the manufacture and restoration of the operation model of Heumgyeonggak-nu.
        15.
        2013.10 서비스 종료(열람 제한)
        The structural deformed shape is important information to structural analysis. SFSM-LS algorithm, the economic and effective estimation method for the structural deformation shapes with limited displacement measuring points is developed(Choi, 2003). In this study, structure internal forces are estimated by using structural deformed shape.
        16.
        2013.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Heumgyeonggaknu is a water-hammering type automatic water clock which was made by Jang Yeong-Sil in 1438. The water clock that is located in Heumgyeonggaknu consists of Suho which is equipped with 2-stage overflow. Constant water wheel power is generated by supplying a fixed amount of water of Suho to Sususang, and this power is transferred to each floor at the same time. The 1st floor rotation wheel of Gasan consists of the operation structure which has the shape of umbrella ribs. The 2nd floor rotation wheel is made so that the 12 hour signal, Gyeong-Jeom signal, and Jujeon constitute a systematic configuration. The 3rd floor rotation wheel is made so that the signal and rotation of Ongnyeo and four gods can be accomplished. Based on the above conceptual design, this paper analyzed the internal signal generation and power transmission of Heumgyeonggaknu.
        17.
        2006.10 KCI 등재 서비스 종료(열람 제한)
        옥수수의 종자발육에 ethylene이 미치는 영향을 알기 위하여 마치종, 단옥수수, 초당옥수의 배와 배유의 발육과 ethylene 발생을 조사하였다. 그리고 초당옥수수에 ethylene 발생과 작용을 조절하는 aminoethoxyvinyl glycine(AVG), silver thiosulfate(STS), ethephon(2-chloroethylphosphonic acid, CEPA)를 출사 후 9 및 21일에 전 식물체와 포엽에 처리하여 ethylene 발생양상과 배와 배유의 발육을 조사하여 채종 시 종자발달을 촉진할 수 있는 방법을 찾고자 하였으며, 그 결과를 요약하면 다음과 같다. 1. 마치종은 배와 배유 모두 출사 후 56일까지 건물중이 증가하였다. 그러나 단옥수수와 초당옥수수의 배는 출사 후 각각 56일 및 49일까지, 배유는 출사 후 35일 및 28일까지 증가하였다. 2. 종자의 ethylene 발생량은 초당옥수수가 단옥수수나 마치종보다 많았다. 3. 배유조직의 변화는 출사 후 21일부터 배의 끝 부분에서 동공이 생기기 시작하여 마치종은 동공이 유지되나 단옥수수는 출수 후 42일에는 동공이 붕괴되었고, 초당옥수수는 배 위쪽 및 옆쪽까지 동공이 생겼다가 수축되었다. 4. 초당옥수수 품종 Xtrasweet 82에서 AVG와 STS는 ethylene 발생량을 감소시키고 100립중을 다소 증가시켰으나, CEPA는 ethylene 발생량을 증가시키고 100립중을 감소 시키는 경향이었다. 5. CEPA 처리는 배유에 동공이 발생하는 시기가 다소 빨랐으나 AVG와 STS 처리는 큰 효과가 없었다.
        19.
        2000.09 KCI 등재 서비스 종료(열람 제한)
        RAPD 분석을 통한 marker선별과 건조약재의 비교, 그리고 내부형태 특징을 통해 당귀3종(種)을 구별할 수 있는 결과를 요약하면 다음과 같다. 1. 50개의 primer중 5개의 primer에서 당귀류 3품종을 모두 구별할 수 있는 특이적인 band가 나타났다. 2. 유연관계 분석에서 중국당귀와 일당귀가 참당귀보다 더 근연관계임을 알 수 있었다. 3. 신선한 잎과 건조된 약재에서 RAPD 재현성이 확인되어 RAPD 분석법을 통해 당귀감별에 응용할 수 있을 것으로 사료된다. 4. 뿌리 내부구조에서 중국당귀는 정상적인 2기사부와 2기목부에 덧붙여 일부 이상비대생장을 보였고, 일당귀나 참당귀의 도관절에 비하여 더 넓고 짧아 계통학적으로 훨씬 더 진화된 것으로 여겨진다. 5. 일당귀는 현저하게 두꺼운 코르크층이 발달한 반면 참당귀의 코르크층 아래에 5~7층의 후각세포층이 환상으로 발달하여 뚜렷한 대조를 이루었다.