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        검색결과 70

        21.
        2016.10 서비스 종료(열람 제한)
        Background : The objective of this study was to Amomum tsao-ko Crevost et Lemarié, (Zingiberaceae) is widely distributed among several countries in South Asia and Southeast Asia. It is a well known spice in Asia, produces a nice refreshing effect in the mouth. Additionally, it's dried fruit is used in Traditional Chinese Medicine (TCM) for cardiac diseases, edema, eye trouble, skin, itch and impotence. The objective of this study was evaluated the inhibitory activity on adipogenesis in 3T3-L1 cells from A. tsao-ko. Methods and Results : The fruits of A. tsao-ko were extracted with 80% EtOH two times at room temperature. The EtOH extract was suspended in distilled water and partitioned with solvent to give CH2Cl2, EtOAc and n-BuOH. The CH2Cl2 was suspended in n-hexane and partitioned with solvent to give 50%, 70% and 90% MeOH. The purification of each fraction by column chromatography separation and HPLC analysis. Consequently, several constituents were isolated five known compounds. The identification and structural elucidation of compounds were established by using NMR (1D and 2D) and mass spectrometry. Conclusion : These compounds were identified as fluorenone (1), phenanthrene (2), anthracene (3), methyl linolenate (4), 1,2-benzenediol (5). All isolates were tested for their inhibitory activities on adipogenesis in 3T3-L1 cells.
        22.
        2016.10 서비스 종료(열람 제한)
        Background : Amomum tsao-ko (Zingiberaceae) is widely distributed among several countries in Asia. It’s dried fruit is widely used in Korea for medical plant, China and Japan for the treatment of dyspepsia, eliminates, vomiting, abdominal pain, phlegm, warms the spleen, and malaria. In this study, we describe the structural determination of the new compounds and the inhibitory activities of isolated compounds against LPS-induced NO production in RAW264.7 cells. Methods and Results : The fruits of A. tsao-ko were extracted with 80% EtOH two times at room temperature. The EtOH extract was suspended in distilled water and partitioned with solvent to give CH2Cl2, EtOAc and n-BuOH. The CH2Cl2 was suspended in n-hexane and partitioned with solvent to give 50%, 70% and 90% MeOH. The purification of each fraction by column chromatography separation and HPLC analysis. Consequently, one new benzaldehyde (1) and two new cycloterpenals (2 and 3) along with five known compounds (4 –8) have been isolated from the fruits of A. tsao-ko. The structure and relative stereochemistry were determined from HRMS, 1D and extensive 2D NMR techniques as well as by comparison of their data with the published values. Conclusion : These compounds were identified as Amotsaokonal A (1), Amotsaokonal B (2), Amotsaokonal C (3), methyl linolenate (4), trans-nerolidol (5), (2E)-dodecenyl acetate (6), (2E)-dodecenyl acetate (7), and pyrrole-2-carboxylic acid (8). All isolates were tested for their inhibitory activities on LPS-induced nitric oxide production in RAW264.7 cells.
        23.
        2016.10 서비스 종료(열람 제한)
        Based on the experiment, characteristic of local stresses and deformation in the anchorhead and wedges with prestressing of PSC slab was investigated in this study. As a result, local stresses exceeded yeild stress in the contacts of anchorhead and wedges and in the lower sides of anchorhead
        24.
        2016.05 서비스 종료(열람 제한)
        Background : Phenolic compounds were isolated from the twig of Broussoneita Kazinoki. Their structures were established on the basis of extensive spectroscopic (MS, 1D , and 2D NMR) data analysis and by comparison with the spectroscopic data reported in the literature. Methods and Results : The twig of B. Kazinoki were extracted 60% aqueous ethanol for 3 days at room temperature. The extract was filtered and concentrated by vacuum evaporator. And then, extract was partitioned using hexane, methylene chloride (MC), ethyl acetate (EtOAc), n-butyl alcohol (BuOH) and H2O, successively. The extraction was separated by using prep-HPLC, and the structure was analyzed by Mass spectrometry (MS) and 1H-, 13C-, 1H-1H COSY, HSQC, HMBC NMR data. Conclusion : These compounds were identified as chlorogenic acid (1), ferulic acid (2), p-coumaric acid (3), taxifolin (4), marmesin (5), 5-methoxy marmesin (6), pinoresinol (7), syringaresinol (8), quercetin (9), broussonin A (10), broussonin B (11), broussoflavonol A (12), broussoflavonol B (13), kazinol A (14), and 5,7,3',4'-tetrahydroxy-3-methoxy-8,5'-diprenylflavone (15).
        25.
        2015.04 서비스 종료(열람 제한)
        The thermal load must be considered to design cable supported bridges as a variable load. The thermal load recommended by Korean design code might be different to real temperature distribution in the bridges because the thermal load proposed by Korean design code is referred to Eurocode, etc. Therefore this study proposes the temperature distribution of cable supported bridges In Korea based on measurements.
        26.
        2015.02 서비스 종료(열람 제한)
        최근 다양한 공간정보 활용에 대한 인식이 높아지면서 공간정보산업은 상당 수준 발전하고 있으며, 이에 따른 지리정보와 관련된 다양한 웹서비스가 제공되고 웹을 통한 정보 활용이 가능한 환경으로 발전하였다(2007, 장윤섭). 이러한 웹을 통한 정보 유통의 수요가 증가함에 따라 자료 제공측면에서 표준화의 중요성이 갈수록 강조되고 있다. 웹서비스 표준화 관련 분야는 ISO (International Organizatio n for Standard), OASIS (Organization for the Advancement of Structured Information Standards ), WS-I (Web Services Interoperability Organization) 등 국제 표준화 기구에서 연구가 진행되고 있으며, 특히 2014년 현재 총 505개의 기관이 참여하고 있는 OGC (Open Geospatial Consortium)에서는 Web GIS Service와 관련하여 표준화가 진행되고 있다(http://www.opengeospatial.org). 그러나 우리나라의 경우 공간정보 분야에서 그 필요성에 비하여 아직까지는 표준에 대한 관심과 개발 및 적용을 위한 노력이 다소 미흡한 실정이다(2010, 이기원). 하천공간정보의 표준화 및 웹서비스에 대한 효율적인 제공 체계 구축을 위해서는 공간정보 제공에 적합한 표준 선정과 적용이 필요하다. 국제 표준 중 OGC 표준 기반의 WMS (Web Map Service)는 분산환경에서 지리적으로 등록된 Map Image를 요청하는 표준 프로토콜이며, 별도의 프로그램 없이 웹으로 지리정보를 제공하기 때문에 하천공간정보 웹서비스 표준화에 대하여 WMS 준용을 고려할 필요가 있다. 따라서 OGC 표준 기반의 WMS를 활용하여 하천공간정보에 대하여 효율적인 데이터 처리 및 공간 분석 등을 적용하기 위한 추진 방안을 제시하였다. 이를 통해 표준화된 웹 기반 API(Application Programming interface)를 활용하여 효율적이고 체계적인 하천공간정보를 제공할 수 있는 기틀 마련이 가능할 것으로 사료된다.
        27.
        2015.02 서비스 종료(열람 제한)
        2009년 OECD (Organization for Economic Co-operation and Development])는 열린 정부의 실현을 위해 시민 참여를 통한 정책 평가 향상, 신기술과 참여형 웹의 적극적 활용을 통합 지침으로 제시하였다. 공공데이터와 민간데이터의 조합으로 경제 활성화에 기여할 다양한 정책들이 추진되고 있다. 특히 미국, 영국 등은 새로운 웹 기술을 적극적으로 활용하여 정부의 공공데이터를 공개하고 있다. 아울러, 하천 관련 정보의 종류와 양이 다양해지고 있으며, 하천 정보의 중요성 확대로 인해 수요가 증가하면서 한계점으로 지적되고 있는 정보 공유와 관리의 실효성을 향상시키기 위해서는 무엇보다 자료표준화가 선행되어야 하고, 하천 관련 정보 항목의 정의 및 자료 생성기준의 표준화와 더불어 정보공유 프로토콜 등 자료 공유의 표준화된 기법 도입이 필요하다. 본 연구에서는 오픈데이터 기반의 효율적인 하천공간정보의 관리 및 공유를 위한 관련기관 및 대민서비스 정보 제공, 공간분석을 위한 정보 분류 체계 구성, 메타데이터 구축, 네트워크상에서 쉽게 접근이 가능하고 원하는 데이터를 얻을 수 있는 서비스 시스템 등에 대한 국내외 표준현황을 조사하고 분석하여 표준을 준수한 하천공간정보 제공 시스템을 개발하였다.
        31.
        2014.10 서비스 종료(열람 제한)
        The wind load characteristics are represented by wind speed, wind direction, turbulence intensity, roughness index of terrain, spectral density and so on. In this paper, the wind load characteristics of long span bridges in general national roads are evaluated based on measured data of wind speed and direction.
        32.
        2014.10 서비스 종료(열람 제한)
        This paper developed analysis model with measured data and geometric nonlinearity for more precise evaluation of structure behavior of suspension bridge. This analysis model helps to make plan and evaluate of structure behavior for accidents such as traffic, typhoon and earthquake. Also, this helps to make maintenance and management plan for structure.
        35.
        2014.04 서비스 종료(열람 제한)
        The static aerodynamic forces are composed of six components. Three components of them such as drag force, lift force and pitching moment are the biggest influence on the structure. These aerodynamic forces are generally evaluated from wind tunnel test or CFD. In this study, drag and lift force coefficients are estimated using relation of actual and analytical displacements. The actual displacements are measured by monitoring system when the bridges were under the typhoon. The analytical displacements due to uniform load are calculated by FEM. Also, the adequacy of estimation method was conformed by comparing the result of this study with that from the wind tunnel test of the similar bridge section.
        36.
        2013.10 서비스 종료(열람 제한)
        The corrosion is a main cause of degradation damage in the steel bridges. The evaluation whether the repair or reconstruction would be need or not for the corroded steel member, is based on cross section and quantity of corroded portion. It is considered reasonable that the evaluation will be base on the endurance of the corroded member. In this study, the bending endurance of the I-shaped steel girder with the local corrosion on the lower flange is discussed by using elastic-plastic finite element analyses. That simple way of estimating it is also proposed.
        40.
        2013.10 서비스 종료(열람 제한)
        Structural damping includes material damping, friction effects at bearing and expansion joints, friction at bolted joints and mechanical damping by damper. There is not analytical basis for estimating the damping ratios. Structural damping ratios can be estimated by measuring forced vibration amplitude of a certain mode but it is almost impossible to vibrate the actual bridges to a certain mode by force. Therefore, RD technique utilizing a lot of ambient vibration data can be a practical method to estimate damping ratio. In this study, the damping ratio is estimated by analyzing the ambient vibration data of three steel cable stayed bridges.
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