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        검색결과 10

        1.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this work, we deal with the feasibility of structural topology optimization for beam designs using retrofits that optimally allocates the reinforcement to the web under the condition that designers set bolt regions for H-beams of different dimensions. Mean compliance or minimal strain energy is considered for the optimization. Volume fraction is given to the design space to assign appropriate steel material quantities. The purpose of this study is to evaluate optimal shapes of stiffeners with the maximum rigidity that improves the axial and shear performance of the H-beam and to satisfy a given safety design standard of H-beam and stiffeners in case arbitrary load effect and resistances. Finally, the effectiveness of stiffness-based topology optimization on stiffeners is verified with several practical applicable examples.
        4,000원
        2.
        2018.10 서비스 종료(열람 제한)
        Background : Aralia continentalis Kitag. (syn. = A. cordata Thunb., Araliaceae) is a traditional medicinal herb spread widely in northeastern Asia, including Korea, China, and Japan. Many constituents from its root extracts, including diterpene and essential oils, have been isolated as active components for antioxidant, anti-inflammatory, analgesic, sedative, antifungal, anti-thrombotic, and growth inhibition. In this study, we describe the structural determination of the two new compounds. Materials and Results : The roots of A. continentalis were collected in Namwon-si, Jeollabuk-do, Korea, in March 2018 and identified by one of the authors (Dr. S. S. Hong). The roots of A. continentalis were extracted with 70% EtOH two times at room temperature. The concentrated residue was subsequently suspended in H2O and partitioned with n-hexane, CH2Cl2, EtOAc and n-BuOH. The n-hexane, CH2Cl2, and EtOAc layer were subjected to sequential column chromatography over silica-gel, RP-18, MPLC and preparative HPLC to isolated the compounds 1 - 30. Consequently, a new nor-ent-pimaran diterpenoid (11) and a new 8-O-4′ type neolignan (25) along with 28 known compounds that included diterpenoids, phenolic derivates, and polyacetylenes have been isolated from the ethanol extract of the roots of A. continentalis. The structures of the new compounds were established by spectroscopic data interpretation, particularly HRESIMS, 1D and 2D NMR data including HSQC and HMBC. Also, those of the known compounds were identified by spectral comparison with those of the reported values. Conclusion : The structures of two new compounds were determined as 18-nor-ent-pimara-9 (11),15-diene-4β-ol (11) and 8-O-4-dehydrocoumaroyl-ferulic acid (25). To our knowledge, compounds 10, 14, 15, 19, 20, 22 – 24, and 26 were isolated and identified from Aralia genus for the first time.
        3.
        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.
        4.
        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.