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Mechanics of Composite Materials - The main purpose of this study is investigation of the effect of CFRP strengthening on the behavior of defective vertical curved steel beams with a square hollow... 相似文献
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Modarresi-Alam AR Najafi P Rostamizadeh M Keykha H Bijanzadeh HR Kleinpeter E 《The Journal of organic chemistry》2007,72(6):2208-2211
The dynamic 1H NMR study of some primary carbamates in the solvents CDCl3 and CD3COCD3 between 183 and 298 K is reported. The free energies of activation, thus obtained (12.4 to 14.3 kcal mol-1), were attributed to the conformational isomerization about the N-C bond. These barriers to rotation show solvent dependence in contrast to the tertiary analogues and are lower in free energy by ca. 2-3 kcal mol-1. 相似文献
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Dynamic 1H NMR (500 MHz) investigation of 4-methylphenoxyimidoyl azides (4-CH3-C6H4-O-CN-Y)-N3, Y=4-CH3-C6H4-SO2-, 4-Br-C6H4-SO2-, C6H5SO2-, CH3-SO2-, -CN in acetone-d6 at temperature range of 195-280 K is reported. The observed free energy barrier (almost 12 kcal mol−1) is attributed to conformational isomerisation about the N-S bond for Y=4-CH3-C6H4-SO2-, 4-Br-C6H4-SO2-, C6H5SO2-, CH3-SO2- and (almost 14 kcal mol−1) to configurational isomerisation (E/Z) about CN bond for Y=-CN. 相似文献
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