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991.
Kinetic equations describing nucleation on active centers are solved numerically to determine the number of supercritical nuclei, nucleation rate, and the number density of nuclei for formation both of droplets from vapor and also crystalline phase from vapor, solution, and melt. Our approach follows standard nucleation model, when the exhaustion of active centers is taken into account via the boundary condition, and thus no additional equation (expressing exhaustion of active centers) is needed. Moreover, we have included into our model lowering of supersaturation of a mother phase as a consequence of the phase transition process within a confined volume. It is shown that the standard model of nucleation on active centers (Avrami approach) gives faster exhaustion of active centers as compared with our model in all systems under consideration. Nucleation rate (in difference to standard approach based on Avrami model) is equal to the time derivative of the total number of nuclei and reaches some maximum with time. At lower nucleation barrier (corresponding to higher initial supersaturation or lower wetting angle of nucleus on the surface of active center) the exhaustion of active centers is faster. Decrease in supersaturation of the mother phase is faster at higher number of active centers. 相似文献
992.
Strict β-controlled glucuronylations without classical neighboring-group participation were achieved by the assistance of a 2,4-O-di-tert-butylsilylene group. Comparison of activation conditions and conformational analysis indicated that the strict β-selectivity was achieved by steric hindrance of the 2,4-O-di-tert-butylsilylene group and not by complex glycosyl intermediates. 相似文献
993.
Masamichi Nakayama Naoko Yamada Yoshikazu Kumashiro Hideko Kanazawa Masayuki Yamato Teruo Okano 《Macromolecular bioscience》2012,12(6):751-760
Thermoresponsive surfaces are prepared via a spin‐coating method with a block copolymer consisting of poly(N‐isopropylacrylamide) (PIPAAm) and poly(butyl methacrylate) (PBMA) on polystyrene surfaces. The PBMA block suppresses the removal of deposited PIPAAm‐based polymers from the surface. The polymer coating affects the temperature‐dependent cellular behavior of the surfaces with respect to protein adsorption. By adjusting layer thicknesses, PBMA‐b‐PIPAAm‐coated surfaces are optimized to regulate the adhesion/detachment of cells by temperature changes. Thus, thermoresponsive polymer‐coated surfaces are able to harvest contiguous cell sheets with their basal extracellular matrix proteins.
994.
995.
Garcia-Martin F Hinou H Matsushita T Hayakawa S Nishimura S 《Organic & biomolecular chemistry》2012,10(8):1612-1617
A standardized and smooth protocol for solid-phase glycopeptides synthesis under microwave irradiation was developed. Double activation system was proved to allow for highly efficient coupling of Tn-Ser/Thr and bulky core 2-Ser/Thr derivatives. Versatility and robustness of the present strategy was demonstrated by constructing a Mucine-1 (MUC1) fragment and glycosylated fragments of tau protein. The success of this approach relies on the combination of microwave energy, a resin consisting totally of polyethylene glycol, a low excess of sugar amino acid and the "double activation" method. 相似文献
996.
Asymmetric addition of arylboronic acids to α,β-unsaturated sulfonyl compounds proceeded in the presence of a rhodium catalyst coordinated with a chiral diene ligand to give high yields of the addition products with high enantioselectivity (96->99.5% ee). The diene ligand was proved to be essential for the formation of the addition products, while the use of a bisphosphine ligand mainly gave the cine-substitution product. 相似文献
997.
Kousuke Nishimura Ikuya Yamada Kengo Oka Yuichi Shimakawa Masaki Azuma 《Journal of Physics and Chemistry of Solids》2014
A new cubic perovskite BaVO3 was synthesized by high-pressure synthesis at 15 GPa, and 1350 °C. Contrary to our expectations that lattice expansion by Ba substitution for Sr would lead to non-centrosymmetric tetragonal distortion, BaVO3 preserved its cubic crystal structure with a=3.94288(3) Å at room temperature and had Fermi-liquid characteristics as SrVO3 down to the lowest temperature. 相似文献
998.
S. Momota M. Mihara D. Nishimura M. Fukuda Y. Kamisho M. Wakabayashi K. Matsuta S. Suzuki M. Nagashima Shengyun Zhu Daqing Yuan Yongnan Zheng Zuo Yi Ping Fan T. Izumikawa A. Kitagawa S. Sato M. Kanazawa M. Torikoshi T. Minamisono Y. Nakamura K. Tashiro A. Honma N. Yoshida H. Shirai T. Ohtsubo T. Nagatomo H. Uenishi K. Iwamoto M. Yaguchi T. Ogura T. Ito K. Yamamura Y. Ichikawa Y. Nojiri J. R. Alonso T. J. M. Symons 《Hyperfine Interactions》2013,218(1-3):53-58
Hyperfine interactions were studied in the intermetallic compound GdRh2Si2 by perturbed angular correlation (PAC) technique using 181Hf(181Ta) probe nuclei. The measurements were performed in the temperature range 15–285 K. The PAC spectra above the antiferromagnetic ordering temperature of the GdRh2Si2 compound (T N ~ 106 K), were analyzed using a model that included only electric quadrupole interactions. The observed major fraction was assigned to the 181Hf(181Ta) probe substituting the Gd atoms. The PAC spectra below Néel temperature were analyzed using combined electric quadrupole and magnetic dipole interactions. The Bhf value at Gd, measured at 15 K was found to be 1.4(1) T which, is smaller, when compared with the values obtained in this compound using other nuclear probes, 155Gd (Bhf ~ 30 T) and 140Ce (Bhf ~ 26 T). The present result using 181Hf(181Ta) probe is quite interesting since it shows that the contribution to Bhf at Gd due the host is smaller than other components which contribute to the hyperfine field. The temperature dependence of Bhf shows an anomalous behavior. 相似文献
999.
Shinji Inagaki Dr. Osamu Ohtani Dr. Yasutomo Goto Dr. Kentaro Okamoto Dr. Masamichi Ikai Dr. Ken‐ichi Yamanaka Takao Tani Dr. Tadashi Okada Dr. 《Angewandte Chemie (International ed. in English)》2009,48(22):4042-4046
Light aqueduct: Periodic mesoporous organosilica exhibits strong light absorption due to densely packed organic chromophores within the pore walls. Light energy absorbed by 125 biphenyl groups in the pore walls is funneled into a single coumarin 1 molecule in the mesochannels with almost 100 % quantum efficiency, and results in significant enhancement of emission from the coumarin 1 dye.
1000.