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排序方式: 共有984条查询结果,搜索用时 15 毫秒
921.
922.
We prove that the set of all complex series which are nonabsolutely convergent is c-algebrable. We establish a similar result for the set of all divergent complex series with bounded partial sums. 相似文献
923.
We prove exponential contraction of renormalization along hybrid classes of infinitely renormalizable unimodal maps (with
arbitrary combinatorics), in any even degree d. We then conclude that orbits of renormalization are asymptotic to the full renormalization horseshoe, which we construct.
Our argument for exponential contraction is based on a precompactness property of the renormalization operator (“beau bounds”),
which is leveraged in the abstract analysis of holomorphic iteration. Besides greater generality, it yields a unified approach
to all combinatorics and degrees: there is no need to account for the varied geometric details of the dynamics, which were
the typical source of contraction in previous restricted proofs. 相似文献
924.
Reliability of calculated (1)H and (13)C NMR chemical shifts for various classes of organic compounds obtained with gauge-invariant atomic orbital (GIAO) approach has been studied at the PBE/3ζ level (as implemented in PRIRODA code) using linear regression analysis with experimental data. Empirical corrections for the calculated chemical shifts δ(H,calc) = δ(PBE/3ζ) - 0.08 ppm (RMS 0.18 ppm, MAD 0.66 ppm) and δ(C,calc) = δ(PBE/) (3) (ζ) - 6.35 ppm (RMS 3.09 ppm, MAD 9.42 ppm) have been developed using the sets of 263 and 308 experimental values for (1)H and (13)C chemical shifts, respectively. The confidence intervals of NMR chemical shifts at 95% confidence probability are δ(H,calc) ± 0.35 ppm for (1)H and δC,calc) ± 6.05 ppm for (13)C. 相似文献
925.
Raquel S. G. R. Seixas Artur M. S. Silva Ibon Alkorta José Elguero 《Monatshefte für Chemie / Chemical Monthly》2011,18(5):731-742
Abstract
We report the synthesis and structural study of eight compounds, either quinolin-4(1H)-ones or quinolines. Tautomerism as well as (E) → (Z) and rotational isomerism were studied both experimentally (1H and 13C NMR) and theoretically [B3LYP/6-311++G(d,p)]. 相似文献926.
Pinto SM Lourenço MA Calvete MJ Abreu AR Rosado MT Burrows HD Pereira MM 《Inorganic chemistry》2011,50(17):7916-7918
Zinc and manganese complexes of porphyrin triads have been synthesized and are shown to be efficient as highly sensitive and selective tripod optical sensors for amines at the picomolar level. 相似文献
927.
Garbacz JK Furmaniak S Terzyk AP Grabiec M 《Journal of colloid and interface science》2011,359(2):512-519
Using the thermodynamic idea of complementary systems, and based on fundamental concepts of the theory of volume filling of micropores, we derived a new universal model describing adsorption from solutions with limited and unlimited miscibility of components. The model takes into account the differences in collision diameters of adsorbed molecules as well as the competitive nature of adsorption from solutions. The applicability of this new approach is tested against experimental data. 相似文献
928.
Djamila Hikem‐Oukacha Yahïa Rachedi Maamar Hamdi Artur M.S. Silva 《Journal of heterocyclic chemistry》2011,48(1):31-37
An efficient synthesis of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one by bromination of dehydroacetic acid in glacial acetic acid is described. Novel 4‐hydroxy‐6‐methyl‐3‐(2‐substituted‐thiazol‐4‐yl)‐2H‐pyran‐2‐ones have been prepared from the reaction of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one with thioamides, thiourea, and diphenylthiocarbazone. The condensation reaction of 6‐methyl‐4H‐furo[3,2c]pyran‐3,4‐dione, obtained from the reaction of 3‐bromoacetyl‐4‐hydroxy‐6‐methyl‐2H‐pyran‐2‐one with aliphatic amines, with benzaldehydes and acetophenones led to novel 2‐arylidene‐6‐methyl‐2H‐furo[3,2‐c]pyran‐3,4‐diones and 6‐(2‐arylprop‐1‐enyl)‐2H‐furo[3,2‐c]pyran‐3,4‐diones. The structure of all compounds was established by elemental analysis, IR, NMR, and mass spectra. J. Heterocyclic Chem., 2011. 相似文献
929.
Airoldi C Cardona F Sironi E Colombo L Salmona M Silva A Nicotra F La Ferla B 《Chemical communications (Cambridge, England)》2011,47(37):10266-10268
A small library of glyco-fused benzopyran compounds has been synthesised. Their interaction features with Aβ peptides have been characterised by using STD-NMR and trNOESY experiments. The conformational analysis of the compounds has also been carried out through molecular mechanics (MM) and molecular dynamics (MD) simulations. 相似文献
930.
Cadeddu A Ciesielski A El Malah T Hecht S Samorì P 《Chemical communications (Cambridge, England)》2011,47(38):10578-10580
First generation poly(triazole-phenylene) dendrimers equipped with peripheral alkyl or carboxylic acid groups to engage in van der Waals and hydrogen-bonding interactions, respectively, assemble into distinct two-dimensional nano-structures at the solid-liquid interface as revealed by high resolution STM investigations. 相似文献