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61.
Efficient and accurate procedure for selecting ground motions matching target response spectrum 总被引:2,自引:0,他引:2
Linear and nonlinear response history analyses have become popular in seismic design and seismic performance evaluation procedures. The accuracy of analysis results depends not only on the accurate analytic models for structures but also on the proper selection of input ground motions. The purpose of this study is to develop a computationally efficient and accurate procedure for selecting ground motions considering the target response spectrum mean and variance, and the correlations between response spectra of different periods. In this procedure, a number of response spectra are simulated equal to the number of ground motions to be selected, using a Monte Carlo simulation. Subsequently, ground motions are selected from a ground motion library to individually match the simulated response spectra, using the proposed selection procedure. This procedure is computationally efficient and accurate in selecting a ground motion that best matches a simulated response spectrum and in determining a scaling factor for the selected ground motion. In order to further improve the selection result, multiple sets of simulated response spectra are considered. The accuracy and efficiency of the proposed procedure are verified with numerical examples. 相似文献
62.
63.
Youngsoo Ha Chang Ho Kim Yeon Ju Lee Jungho Yoon 《Journal of Mathematical Analysis and Applications》2012,394(2):670-682
In this paper, we introduce an improved version of mapped weighted essentially non-oscillatory (WENO) schemes for solving Hamilton–Jacobi equations. To this end, we first discuss new smoothness indicators for WENO construction. Then the new smoothness indicators are combined with the mapping function developed by Henrick et al. (2005) [31]. The proposed scheme yields fifth-order accuracy in smooth regions and sharply resolve discontinuities in the derivatives. Numerical experiments are provided to demonstrate the performance of the proposed schemes on a variety of one-dimensional and two-dimensional problems. 相似文献
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65.
Eun‐Ju Ha Bong‐Soo Kim Eun‐Kyoung Park Ki‐Won Song Sun‐Gu Lee Seong Soo A. An Hyun‐jong Paik 《先进技术聚合物》2013,24(1):75-80
Ni2+‐complexed poly(2‐acetamidoacrylic acid) (PAAA) hydrogel beads were developed for the site‐specific reversible immobilization and purification of the histidine‐tagged green fluorescent protein (His‐tagged GFP). PAAA hydrogel beads were prepared by photopolymerization, and significantly improved mechanical properties of PAAA hydrogel beads were observed in comparison with PAAA hydrogel from our previous study. Confocal laser scanning microscopy was used to determine the binding of His‐tagged GFP to the hydrogel beads in three‐dimensional space. Photoluminescence spectroscopy revealed 89% of binding efficiency of His‐tagged GFP to the Ni2+‐PAAA hydrogel beads, 51% of yielding recovery. The maximum binding capacity of His‐tagged GFP was estimated to be 0.45 µg/mg of Ni2+‐PAAA hydrogel beads. The recombinant His‐tagged GFP from the soluble fraction of E. coli BL21(DE3) cell lysates was purified with Ni2+‐PAAA hydrogel beads. The major advantage of the Ni2+‐PAAA hydrogel beads system was simple preparation procedures of producing the matrix, because PAAA hydrogel beads had relatively enhanced mechanical strength than soft hydrogels. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
66.
Characterization of Nitro-Substituted Polybenzimidazole Synthesized by the Reaction with Nitric Acid
Abstract Nitro-substituted poly[2,2′-(m-phenylene)-5,5′-bibenzimidazole]s (PBIs) were synthesized by the reaction of PBI with nitric acid in sulfuric acid under various conditions. The number of nitro groups substituted on the aromatic ring of PBI per polymeric unit varied from 1.44 to 3.55 according to the reaction conditions. An increase in reaction temperature and concentration of the nitric acid increased the degree of substitution. The inherent viscosity of the substituted polymer increased as the reaction temperature decreased. When the reaction temperature was 30°C, the inherent viscosity of the polymer increased as the concentration of nitric acid increased. The nitro-substituted PBI exhibited polyelectrolyte behavior in formic acid. The nitro groups substituted on PBI were dissociated when the polymer was heated to 450°C, displaying exothermic behavior, and the decomposition of polymer was proportional to its nitro group content. All nitro-substituted PBIs showed better solubilities in polar aprotic and acidic solvents, such as dimethylacetamide, dimethylsulfoxide, dimethylformamide, N-methylpyrrolidone, formic acid, sulfuric acid, and trifluoromethanesulfonic acid. 相似文献
67.
Abstract The copolymerization system of styrene (ST) and citraconic (α-methymaleic) anhydride (CA) was found to form semi-alternating copolymers when polymerized with a total monomer concentration of 4 mol/L in CCl4 at 50°C, with alternating copolymers being formed only when the CA mole fraction in feed was greater than 0.9. More than 50% of the linkage configurations at the cyclic CA units in the copolymers were found to be in cis configuration. This, together with the following observations, is consistent with a participation of the electron donor-acceptor (EDA) complex formed between ST and CA: (a) the complex participation model fits best, although only marginally, to the experimental triad mole fraction of alternating sequences; (b) the alternating monomer unit sequences and the cis linkage configuration at the cyclic CA units are more efficiently formed in non polar CCl4 solutions than in polar methy ethyl ketone. The equilibrium constant for the EDA complexation of ST and CA in CCl4 at 23°C is determined to be 0.142 ± 0.015 L/mol. 相似文献
68.
Xin Qi Sook Kyung Kim Su Jung Han Li Xu Ah Young Jee Ha Na Kim 《Supramolecular chemistry》2013,25(6):455-464
We report a small library of fluorophore-triazine tripod fluorescent system that can accommodate a combination of three different functional groups, such as fluorophore (BODIPY), ligand (or ligands) and auxiliary group. Syntheses, photophysical properties as well as binding properties towards metal ions of these BODIPY-triazine derivatives are described. 相似文献
69.
Cyclodimerization of norbornadiene (NBD) yielding pentacyclic products of exo-trans(cis)endo-structure in the presence of the model catalytically active complex Ni(H)(η4-NBD) has been studied using the DFT/PBE method. The rate-limiting reaction step is the reductive elimination of the metallacycle, the decomposition of the latter yields the norbornadiene dimer. 相似文献
70.
Sang Doo Kim Soonil Kwon Sung Kyun Lee Minsoo Kook Ha Young Lee Ki-Duk Song Hak-Kyo Lee Suk-Hwan Baek Chan Bae Park Yoe-Sik Bae 《Experimental & molecular medicine》2013,45(9):e40
In this study, we examined the therapeutic effects of an immune-stimulating peptide, WKYMVm, in ulcerative colitis. The administration of WKYMVm to dextran sodium sulfate (DSS)-treated mice reversed decreases in body weight, bleeding score and stool score in addition to reversing DSS-induced mucosa destruction and shortened colon. The WKYMVm-induced therapeutic effect against ulcerative colitis was strongly inhibited by a formyl peptide receptor (FPR) 2 antagonist, WRWWWW, indicating the crucial role of FPR2 in this effect. Mechanistically, WKYMVm effectively decreases intestinal permeability by stimulating colon epithelial cell proliferation. WKYMVm also strongly decreases interleukin-23 and transforming growth factor-β production in the colon of DSS-treated mice. We suggest that the potent immune-modulating peptide WKYMVm and its receptor FPR2 may be useful in the development of efficient therapeutic agents against chronic intestinal inflammatory diseases. 相似文献