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121.
Various system reduction methods have been proposed to calculate eigenvalues and eigenvectors with computational efficiency. In the case of system condensation, the method of selecting proper primary degrees of freedom (PDOFs) is crucial because they are closely related to the accuracy and reliability of eigensystem prediction in a reduced system. Although reasonable selection methods for PDOFs have been proposed for undamped systems, these methods cannot be directly extended to damped systems. We propose a PDOF selection method for a damped system. The proposed method is based on the ratio of DOF-wise energy distributions. In order to estimate the energy distribution of the structure, Ritz vectors are obtained using a two-sided Lanczos algorithm. Energy distribution matrices are calculated from the obtained Ritz vectors. Then, degrees of freedom (DOFs) corresponding to the lowest Rayleigh quotients are selected as the PDOFs. The efficiency and reliability of the proposed method are demonstrated using numerical examples. 相似文献
122.
He Seung Lee Seung-Sock Choi Kyung-Youl Baek Soon Man Hong Eung Chan Lee Jong-Chan Lee Seung Sang Hwang 《European Polymer Journal》2012,48(6):1073-1081
The stereo cyclic siloxane compounds having tetra hydroxyl and tetra methyl group were synthesized by hydrolysis of tetrahydrido tetramethyl cyclosiloxane consisting of four stereoisomers. Among the stereo cyclic isomers, cis-trans-cis tetrahydroxyl tetramethyl cyclosiloxane (2) was separated by recrystallization and was used as a monomer species for preparation of ladder-like polymethylsilsesquioxane (PMSQ). The isolated isomer was directly polymerized in THF with potassium carbonate (K2CO3) by systematic ring condensation. The hydrolyzed stereoisomers were characterized by 1H and 29Si NMR, and HPLC. The structure of the synthesized PMSQs were characterized by size exclusion chromatography (SEC), MALDI-TOF mass, 29Si NMR, and small angle X-ray scattering (SAXS). 相似文献
123.
An HH Lee SJ Baek SH Han WB Kim YH Yoon CS Suh SH 《Journal of colloid and interface science》2012,368(1):257-262
The photoluminescence characteristic of the SnO(x)/Sn nanoparticles deposited on a solid supported liquid-crystalline phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine) membrane was probed after plasma etching the nanoparticle monolayer. It was shown that the plasma etching of the nanoparticle surface greatly altered the particle morphology and enhanced the PL effect, especially when the particle size was below 10 nm in spite of strong presence of surrounding carbon. The enhancement mainly stemmed from the growth of a new PL peak due to the additional defect states produced on the nanoparticle surface by the plasma etching. It was also shown that hydrating the SnO(x)/Sn nanoparticles similarly improved the PL response of the nanoparticles as the hydration produced an additional oxygen-rich oxide layer on the particle surface. 相似文献
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Qian Wu Myun-Ho Bang Dae-Young Lee Jin-Gyeong Cho Rak-Hun Jeong Sabina Shrestha Kyung-Tae Lee Hae-Gon Chung Eun-Mi Ahn Nam-In Baek 《Chemistry of Natural Compounds》2012,48(2):281-284
Two new indoles, 2-C-β-D-glucopyranosyl-1-methoxyindole-3-acetonitrile (1) and 6-hydroxy-1-methylindole3-acetonitrile (2), along with two known indoles [caulilexin C (3) and arvelexin (4)], were isolated from turnip roots (Brassica rapa ssp. campestris L.). The structures of the compounds were established on the basis of NMR, FAB-MS, and IR spectroscopic data. 相似文献
126.
Young Baek Kim Young‐A. Kim Kyung‐Sup Yoon 《Macromolecular rapid communications》2006,27(15):1247-1253
Summary: Network polysilsesquioxane spheres made solely of poly(vinylsilsesquioxane) (PVSQ) and poly(3‐mercaptopropylsilsesquioxane) (PMPSQ) were prepared from heterogeneous mixtures of triethylamine (TEA), water, and either vinyltrimethoxysilane (VTMS), or 3‐mercaptopropyltrimethoxysilane (MPTMS). The microscopic, macroscopic observations, and the relationship between the diameters of spheres and the amount of each ingredient in the reaction system, showed that spheres formed via a mechanism similar to emulsion polymerization and suspension polymerization, depending on the reaction conditions. Diameters of spheres could be controlled from tens of nanometers to a few micrometers by adjusting the amounts of TEA, water, and a surfactant. Heating aqueous solutions of metal ions with these spheres produced polysilsesquioxanes (PSQ)‐metal nanoparticle composite spheres. The spheres prepared in this study were characterized by scanning electron microscopy, transmission electron microscopy, solid state NMR spectroscopy, IR spectroscopy, elemental analysis, and differential thermal analysis. These spheres would be useful in recovering metals from their ionic solutions and probes after chemical modifications.
127.
Jin‐Baek Kim Ramakrishnan Ganesan So Young Yoo Jae‐Hak Choi Sang Yup Lee 《Macromolecular rapid communications》2006,27(17):1442-1445
Summary: A simple lithographic process in conjunction with a novel biocompatible nonchemically amplified photoresist material was successfully used for cell patterning. UV light irradiation on selected regions of the nonchemically amplified resist film renders the exposed regions hydrophilic by the formation of carboxylic groups. Mouse fibroblast cells were found to be preferentially aligned and proliferated on the UV light exposed regions of the nonchemically amplified resist film where carboxylic groups were present.
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